diff options
Diffstat (limited to 'net')
33 files changed, 3863 insertions, 2801 deletions
diff --git a/net/dccp/Kconfig b/net/dccp/Kconfig index 7aa2a7acc7ec..206c16ad9c3c 100644 --- a/net/dccp/Kconfig +++ b/net/dccp/Kconfig @@ -25,9 +25,6 @@ config INET_DCCP_DIAG def_tristate y if (IP_DCCP = y && INET_DIAG = y) def_tristate m -config IP_DCCP_ACKVEC - bool - source "net/dccp/ccids/Kconfig" menu "DCCP Kernel Hacking" diff --git a/net/dccp/Makefile b/net/dccp/Makefile index f4f8793aafff..0c1c9af2bf7e 100644 --- a/net/dccp/Makefile +++ b/net/dccp/Makefile @@ -1,6 +1,7 @@ obj-$(CONFIG_IP_DCCP) += dccp.o dccp_ipv4.o -dccp-y := ccid.o feat.o input.o minisocks.o options.o output.o proto.o timer.o +dccp-y := ccid.o feat.o input.o minisocks.o options.o \ + qpolicy.o output.o proto.o timer.o ackvec.o dccp_ipv4-y := ipv4.o @@ -8,8 +9,6 @@ dccp_ipv4-y := ipv4.o obj-$(subst y,$(CONFIG_IP_DCCP),$(CONFIG_IPV6)) += dccp_ipv6.o dccp_ipv6-y := ipv6.o -dccp-$(CONFIG_IP_DCCP_ACKVEC) += ackvec.o - obj-$(CONFIG_INET_DCCP_DIAG) += dccp_diag.o obj-$(CONFIG_NET_DCCPPROBE) += dccp_probe.o diff --git a/net/dccp/ackvec.c b/net/dccp/ackvec.c index 1e8be246ad15..41819848bdda 100644 --- a/net/dccp/ackvec.c +++ b/net/dccp/ackvec.c @@ -1,445 +1,375 @@ /* * net/dccp/ackvec.c * - * An implementation of the DCCP protocol + * An implementation of Ack Vectors for the DCCP protocol + * Copyright (c) 2007 University of Aberdeen, Scotland, UK * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; version 2 of the License; */ - -#include "ackvec.h" #include "dccp.h" - -#include <linux/dccp.h> -#include <linux/init.h> -#include <linux/errno.h> #include <linux/kernel.h> -#include <linux/skbuff.h> #include <linux/slab.h> -#include <net/sock.h> - static struct kmem_cache *dccp_ackvec_slab; static struct kmem_cache *dccp_ackvec_record_slab; -static struct dccp_ackvec_record *dccp_ackvec_record_new(void) +struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority) { - struct dccp_ackvec_record *avr = - kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC); + struct dccp_ackvec *av = kmem_cache_zalloc(dccp_ackvec_slab, priority); - if (avr != NULL) - INIT_LIST_HEAD(&avr->avr_node); - - return avr; + if (av != NULL) { + av->av_buf_head = av->av_buf_tail = DCCPAV_MAX_ACKVEC_LEN - 1; + INIT_LIST_HEAD(&av->av_records); + } + return av; } -static void dccp_ackvec_record_delete(struct dccp_ackvec_record *avr) +static void dccp_ackvec_purge_records(struct dccp_ackvec *av) { - if (unlikely(avr == NULL)) - return; - /* Check if deleting a linked record */ - WARN_ON(!list_empty(&avr->avr_node)); - kmem_cache_free(dccp_ackvec_record_slab, avr); + struct dccp_ackvec_record *cur, *next; + + list_for_each_entry_safe(cur, next, &av->av_records, avr_node) + kmem_cache_free(dccp_ackvec_record_slab, cur); + INIT_LIST_HEAD(&av->av_records); } -static void dccp_ackvec_insert_avr(struct dccp_ackvec *av, - struct dccp_ackvec_record *avr) +void dccp_ackvec_free(struct dccp_ackvec *av) { - /* - * AVRs are sorted by seqno. Since we are sending them in order, we - * just add the AVR at the head of the list. - * -sorbo. - */ - if (!list_empty(&av->av_records)) { - const struct dccp_ackvec_record *head = - list_entry(av->av_records.next, - struct dccp_ackvec_record, - avr_node); - BUG_ON(before48(avr->avr_ack_seqno, head->avr_ack_seqno)); + if (likely(av != NULL)) { + dccp_ackvec_purge_records(av); + kmem_cache_free(dccp_ackvec_slab, av); } - - list_add(&avr->avr_node, &av->av_records); } -int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb) +/** + * dccp_ackvec_update_records - Record information about sent Ack Vectors + * @av: Ack Vector records to update + * @seqno: Sequence number of the packet carrying the Ack Vector just sent + * @nonce_sum: The sum of all buffer nonces contained in the Ack Vector + */ +int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seqno, u8 nonce_sum) { - struct dccp_sock *dp = dccp_sk(sk); - struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec; - /* Figure out how many options do we need to represent the ackvec */ - const u16 nr_opts = DIV_ROUND_UP(av->av_vec_len, DCCP_MAX_ACKVEC_OPT_LEN); - u16 len = av->av_vec_len + 2 * nr_opts, i; - u32 elapsed_time; - const unsigned char *tail, *from; - unsigned char *to; struct dccp_ackvec_record *avr; - suseconds_t delta; - - if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) - return -1; - - delta = ktime_us_delta(ktime_get_real(), av->av_time); - elapsed_time = delta / 10; - if (elapsed_time != 0 && - dccp_insert_option_elapsed_time(sk, skb, elapsed_time)) - return -1; - - avr = dccp_ackvec_record_new(); + avr = kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC); if (avr == NULL) - return -1; - - DCCP_SKB_CB(skb)->dccpd_opt_len += len; - - to = skb_push(skb, len); - len = av->av_vec_len; - from = av->av_buf + av->av_buf_head; - tail = av->av_buf + DCCP_MAX_ACKVEC_LEN; - - for (i = 0; i < nr_opts; ++i) { - int copylen = len; - - if (len > DCCP_MAX_ACKVEC_OPT_LEN) - copylen = DCCP_MAX_ACKVEC_OPT_LEN; - - *to++ = DCCPO_ACK_VECTOR_0; - *to++ = copylen + 2; - - /* Check if buf_head wraps */ - if (from + copylen > tail) { - const u16 tailsize = tail - from; - - memcpy(to, from, tailsize); - to += tailsize; - len -= tailsize; - copylen -= tailsize; - from = av->av_buf; - } - - memcpy(to, from, copylen); - from += copylen; - to += copylen; - len -= copylen; - } + return -ENOBUFS; + avr->avr_ack_seqno = seqno; + avr->avr_ack_ptr = av->av_buf_head; + avr->avr_ack_ackno = av->av_buf_ackno; + avr->avr_ack_nonce = nonce_sum; + avr->avr_ack_runlen = dccp_ackvec_runlen(av->av_buf + av->av_buf_head); /* - * From RFC 4340, A.2: - * - * For each acknowledgement it sends, the HC-Receiver will add an - * acknowledgement record. ack_seqno will equal the HC-Receiver - * sequence number it used for the ack packet; ack_ptr will equal - * buf_head; ack_ackno will equal buf_ackno; and ack_nonce will - * equal buf_nonce. + * When the buffer overflows, we keep no more than one record. This is + * the simplest way of disambiguating sender-Acks dating from before the + * overflow from sender-Acks which refer to after the overflow; a simple + * solution is preferable here since we are handling an exception. */ - avr->avr_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq; - avr->avr_ack_ptr = av->av_buf_head; - avr->avr_ack_ackno = av->av_buf_ackno; - avr->avr_ack_nonce = av->av_buf_nonce; - avr->avr_sent_len = av->av_vec_len; - - dccp_ackvec_insert_avr(av, avr); + if (av->av_overflow) + dccp_ackvec_purge_records(av); + /* + * Since GSS is incremented for each packet, the list is automatically + * arranged in descending order of @ack_seqno. + */ + list_add(&avr->avr_node, &av->av_records); - dccp_pr_debug("%s ACK Vector 0, len=%d, ack_seqno=%llu, " - "ack_ackno=%llu\n", - dccp_role(sk), avr->avr_sent_len, + dccp_pr_debug("Added Vector, ack_seqno=%llu, ack_ackno=%llu (rl=%u)\n", (unsigned long long)avr->avr_ack_seqno, - (unsigned long long)avr->avr_ack_ackno); + (unsigned long long)avr->avr_ack_ackno, + avr->avr_ack_runlen); return 0; } -struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority) +static struct dccp_ackvec_record *dccp_ackvec_lookup(struct list_head *av_list, + const u64 ackno) { - struct dccp_ackvec *av = kmem_cache_alloc(dccp_ackvec_slab, priority); - - if (av != NULL) { - av->av_buf_head = DCCP_MAX_ACKVEC_LEN - 1; - av->av_buf_ackno = UINT48_MAX + 1; - av->av_buf_nonce = 0; - av->av_time = ktime_set(0, 0); - av->av_vec_len = 0; - INIT_LIST_HEAD(&av->av_records); + struct dccp_ackvec_record *avr; + /* + * Exploit that records are inserted in descending order of sequence + * number, start with the oldest record first. If @ackno is `before' + * the earliest ack_ackno, the packet is too old to be considered. + */ + list_for_each_entry_reverse(avr, av_list, avr_node) { + if (avr->avr_ack_seqno == ackno) + return avr; + if (before48(ackno, avr->avr_ack_seqno)) + break; } - - return av; + return NULL; } -void dccp_ackvec_free(struct dccp_ackvec *av) +/* + * Buffer index and length computation using modulo-buffersize arithmetic. + * Note that, as pointers move from right to left, head is `before' tail. + */ +static inline u16 __ackvec_idx_add(const u16 a, const u16 b) { - if (unlikely(av == NULL)) - return; - - if (!list_empty(&av->av_records)) { - struct dccp_ackvec_record *avr, *next; - - list_for_each_entry_safe(avr, next, &av->av_records, avr_node) { - list_del_init(&avr->avr_node); - dccp_ackvec_record_delete(avr); - } - } - - kmem_cache_free(dccp_ackvec_slab, av); + return (a + b) % DCCPAV_MAX_ACKVEC_LEN; } -static inline u8 dccp_ackvec_state(const struct dccp_ackvec *av, - const u32 index) +static inline u16 __ackvec_idx_sub(const u16 a, const u16 b) { - return av->av_buf[index] & DCCP_ACKVEC_STATE_MASK; + return __ackvec_idx_add(a, DCCPAV_MAX_ACKVEC_LEN - b); } -static inline u8 dccp_ackvec_len(const struct dccp_ackvec *av, - const u32 index) +u16 dccp_ackvec_buflen(const struct dccp_ackvec *av) { - return av->av_buf[index] & DCCP_ACKVEC_LEN_MASK; + if (unlikely(av->av_overflow)) + return DCCPAV_MAX_ACKVEC_LEN; + return __ackvec_idx_sub(av->av_buf_tail, av->av_buf_head); } -/* - * If several packets are missing, the HC-Receiver may prefer to enter multiple - * bytes with run length 0, rather than a single byte with a larger run length; - * this simplifies table updates if one of the missing packets arrives. +/** + * dccp_ackvec_update_old - Update previous state as per RFC 4340, 11.4.1 + * @av: non-empty buffer to update + * @distance: negative or zero distance of @seqno from buf_ackno downward + * @seqno: the (old) sequence number whose record is to be updated + * @state: state in which packet carrying @seqno was received */ -static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av, - const unsigned int packets, - const unsigned char state) +static void dccp_ackvec_update_old(struct dccp_ackvec *av, s64 distance, + u64 seqno, enum dccp_ackvec_states state) { - unsigned int gap; - long new_head; + u16 ptr = av->av_buf_head; - if (av->av_vec_len + packets > DCCP_MAX_ACKVEC_LEN) - return -ENOBUFS; + BUG_ON(distance > 0); + if (unlikely(dccp_ackvec_is_empty(av))) + return; - gap = packets - 1; - new_head = av->av_buf_head - packets; + do { + u8 runlen = dccp_ackvec_runlen(av->av_buf + ptr); - if (new_head < 0) { - if (gap > 0) { - memset(av->av_buf, DCCP_ACKVEC_STATE_NOT_RECEIVED, - gap + new_head + 1); - gap = -new_head; + if (distance + runlen >= 0) { + /* + * Only update the state if packet has not been received + * yet. This is OK as per the second table in RFC 4340, + * 11.4.1; i.e. here we are using the following table: + * RECEIVED + * 0 1 3 + * S +---+---+---+ + * T 0 | 0 | 0 | 0 | + * O +---+---+---+ + * R 1 | 1 | 1 | 1 | + * E +---+---+---+ + * D 3 | 0 | 1 | 3 | + * +---+---+---+ + * The "Not Received" state was set by reserve_seats(). + */ + if (av->av_buf[ptr] == DCCPAV_NOT_RECEIVED) + av->av_buf[ptr] = state; + else + dccp_pr_debug("Not changing %llu state to %u\n", + (unsigned long long)seqno, state); + break; } - new_head += DCCP_MAX_ACKVEC_LEN; - } - av->av_buf_head = new_head; + distance += runlen + 1; + ptr = __ackvec_idx_add(ptr, 1); - if (gap > 0) - memset(av->av_buf + av->av_buf_head + 1, - DCCP_ACKVEC_STATE_NOT_RECEIVED, gap); + } while (ptr != av->av_buf_tail); +} - av->av_buf[av->av_buf_head] = state; - av->av_vec_len += packets; - return 0; +/* Mark @num entries after buf_head as "Not yet received". */ +static void dccp_ackvec_reserve_seats(struct dccp_ackvec *av, u16 num) +{ + u16 start = __ackvec_idx_add(av->av_buf_head, 1), + len = DCCPAV_MAX_ACKVEC_LEN - start; + + /* check for buffer wrap-around */ + if (num > len) { + memset(av->av_buf + start, DCCPAV_NOT_RECEIVED, len); + start = 0; + num -= len; + } + if (num) + memset(av->av_buf + start, DCCPAV_NOT_RECEIVED, num); } -/* - * Implements the RFC 4340, Appendix A +/** + * dccp_ackvec_add_new - Record one or more new entries in Ack Vector buffer + * @av: container of buffer to update (can be empty or non-empty) + * @num_packets: number of packets to register (must be >= 1) + * @seqno: sequence number of the first packet in @num_packets + * @state: state in which packet carrying @seqno was received */ -int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, - const u64 ackno, const u8 state) +static void dccp_ackvec_add_new(struct dccp_ackvec *av, u32 num_packets, + u64 seqno, enum dccp_ackvec_states state) { - /* - * Check at the right places if the buffer is full, if it is, tell the - * caller to start dropping packets till the HC-Sender acks our ACK - * vectors, when we will free up space in av_buf. - * - * We may well decide to do buffer compression, etc, but for now lets - * just drop. - * - * From Appendix A.1.1 (`New Packets'): - * - * Of course, the circular buffer may overflow, either when the - * HC-Sender is sending data at a very high rate, when the - * HC-Receiver's acknowledgements are not reaching the HC-Sender, - * or when the HC-Sender is forgetting to acknowledge those acks - * (so the HC-Receiver is unable to clean up old state). In this - * case, the HC-Receiver should either compress the buffer (by - * increasing run lengths when possible), transfer its state to - * a larger buffer, or, as a last resort, drop all received - * packets, without processing them whatsoever, until its buffer - * shrinks again. - */ + u32 num_cells = num_packets; - /* See if this is the first ackno being inserted */ - if (av->av_vec_len == 0) { - av->av_buf[av->av_buf_head] = state; - av->av_vec_len = 1; - } else if (after48(ackno, av->av_buf_ackno)) { - const u64 delta = dccp_delta_seqno(av->av_buf_ackno, ackno); + if (num_packets > DCCPAV_BURST_THRESH) { + u32 lost_packets = num_packets - 1; + DCCP_WARN("Warning: large burst loss (%u)\n", lost_packets); /* - * Look if the state of this packet is the same as the - * previous ackno and if so if we can bump the head len. + * We received 1 packet and have a loss of size "num_packets-1" + * which we squeeze into num_cells-1 rather than reserving an + * entire byte for each lost packet. + * The reason is that the vector grows in O(burst_length); when + * it grows too large there will no room left for the payload. + * This is a trade-off: if a few packets out of the burst show + * up later, their state will not be changed; it is simply too + * costly to reshuffle/reallocate/copy the buffer each time. + * Should such problems persist, we will need to switch to a + * different underlying data structure. */ - if (delta == 1 && - dccp_ackvec_state(av, av->av_buf_head) == state && - dccp_ackvec_len(av, av->av_buf_head) < DCCP_ACKVEC_LEN_MASK) - av->av_buf[av->av_buf_head]++; - else if (dccp_ackvec_set_buf_head_state(av, delta, state)) - return -ENOBUFS; - } else { - /* - * A.1.2. Old Packets - * - * When a packet with Sequence Number S <= buf_ackno - * arrives, the HC-Receiver will scan the table for - * the byte corresponding to S. (Indexing structures - * could reduce the complexity of this scan.) - */ - u64 delta = dccp_delta_seqno(ackno, av->av_buf_ackno); - u32 index = av->av_buf_head; + for (num_packets = num_cells = 1; lost_packets; ++num_cells) { + u8 len = min(lost_packets, (u32)DCCPAV_MAX_RUNLEN); - while (1) { - const u8 len = dccp_ackvec_len(av, index); - const u8 av_state = dccp_ackvec_state(av, index); - /* - * valid packets not yet in av_buf have a reserved - * entry, with a len equal to 0. - */ - if (av_state == DCCP_ACKVEC_STATE_NOT_RECEIVED && - len == 0 && delta == 0) { /* Found our - reserved seat! */ - dccp_pr_debug("Found %llu reserved seat!\n", - (unsigned long long)ackno); - av->av_buf[index] = state; - goto out; - } - /* len == 0 means one packet */ - if (delta < len + 1) - goto out_duplicate; - - delta -= len + 1; - if (++index == DCCP_MAX_ACKVEC_LEN) - index = 0; + av->av_buf_head = __ackvec_idx_sub(av->av_buf_head, 1); + av->av_buf[av->av_buf_head] = DCCPAV_NOT_RECEIVED | len; + + lost_packets -= len; } } - av->av_buf_ackno = ackno; - av->av_time = ktime_get_real(); -out: - return 0; + if (num_cells + dccp_ackvec_buflen(av) >= DCCPAV_MAX_ACKVEC_LEN) { + DCCP_CRIT("Ack Vector buffer overflow: dropping old entries\n"); + av->av_overflow = true; + } + + av->av_buf_head = __ackvec_idx_sub(av->av_buf_head, num_packets); + if (av->av_overflow) + av->av_buf_tail = av->av_buf_head; -out_duplicate: - /* Duplicate packet */ - dccp_pr_debug("Received a dup or already considered lost " - "packet: %llu\n", (unsigned long long)ackno); - return -EILSEQ; + av->av_buf[av->av_buf_head] = state; + av->av_buf_ackno = seqno; + + if (num_packets > 1) + dccp_ackvec_reserve_seats(av, num_packets - 1); } -static void dccp_ackvec_throw_record(struct dccp_ackvec *av, - struct dccp_ackvec_record *avr) +/** + * dccp_ackvec_input - Register incoming packet in the buffer + */ +void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb) { - struct dccp_ackvec_record *next; + u64 seqno = DCCP_SKB_CB(skb)->dccpd_seq; + enum dccp_ackvec_states state = DCCPAV_RECEIVED; - /* sort out vector length */ - if (av->av_buf_head <= avr->avr_ack_ptr) - av->av_vec_len = avr->avr_ack_ptr - av->av_buf_head; - else - av->av_vec_len = DCCP_MAX_ACKVEC_LEN - 1 - - av->av_buf_head + avr->avr_ack_ptr; + if (dccp_ackvec_is_empty(av)) { + dccp_ackvec_add_new(av, 1, seqno, state); + av->av_tail_ackno = seqno; - /* free records */ - list_for_each_entry_safe_from(avr, next, &av->av_records, avr_node) { - list_del_init(&avr->avr_node); - dccp_ackvec_record_delete(avr); - } -} + } else { + s64 num_packets = dccp_delta_seqno(av->av_buf_ackno, seqno); + u8 *current_head = av->av_buf + av->av_buf_head; -void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk, - const u64 ackno) -{ - struct dccp_ackvec_record *avr; + if (num_packets == 1 && + dccp_ackvec_state(current_head) == state && + dccp_ackvec_runlen(current_head) < DCCPAV_MAX_RUNLEN) { - /* - * If we traverse backwards, it should be faster when we have large - * windows. We will be receiving ACKs for stuff we sent a while back - * -sorbo. - */ - list_for_each_entry_reverse(avr, &av->av_records, avr_node) { - if (ackno == avr->avr_ack_seqno) { - dccp_pr_debug("%s ACK packet 0, len=%d, ack_seqno=%llu, " - "ack_ackno=%llu, ACKED!\n", - dccp_role(sk), 1, - (unsigned long long)avr->avr_ack_seqno, - (unsigned long long)avr->avr_ack_ackno); - dccp_ackvec_throw_record(av, avr); - break; - } else if (avr->avr_ack_seqno > ackno) - break; /* old news */ + *current_head += 1; + av->av_buf_ackno = seqno; + + } else if (num_packets > 0) { + dccp_ackvec_add_new(av, num_packets, seqno, state); + } else { + dccp_ackvec_update_old(av, num_packets, seqno, state); + } } } -static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av, - struct sock *sk, u64 *ackno, - const unsigned char len, - const unsigned char *vector) -{ - unsigned char i; - struct dccp_ackvec_record *avr; +/** + * dccp_ackvec_clear_state - Perform house-keeping / garbage-collection + * This routine is called when the peer acknowledges the receipt of Ack Vectors + * up to and including @ackno. While based on on section A.3 of RFC 4340, here + * are additional precautions to prevent corrupted buffer state. In particular, + * we use tail_ackno to identify outdated records; it always marks the earliest + * packet of group (2) in 11.4.2. + */ +void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno) + { + struct dccp_ackvec_record *avr, *next; + u8 runlen_now, eff_runlen; + s64 delta; - /* Check if we actually sent an ACK vector */ - if (list_empty(&av->av_records)) + avr = dccp_ackvec_lookup(&av->av_records, ackno); + if (avr == NULL) return; + /* + * Deal with outdated acknowledgments: this arises when e.g. there are + * several old records and the acks from the peer come in slowly. In + * that case we may still have records that pre-date tail_ackno. + */ + delta = dccp_delta_seqno(av->av_tail_ackno, avr->avr_ack_ackno); + if (delta < 0) + goto free_records; + /* + * Deal with overlapping Ack Vectors: don't subtract more than the + * number of packets between tail_ackno and ack_ackno. + */ + eff_runlen = delta < avr->avr_ack_runlen ? delta : avr->avr_ack_runlen; - i = len; + runlen_now = dccp_ackvec_runlen(av->av_buf + avr->avr_ack_ptr); /* - * XXX - * I think it might be more efficient to work backwards. See comment on - * rcv_ackno. -sorbo. + * The run length of Ack Vector cells does not decrease over time. If + * the run length is the same as at the time the Ack Vector was sent, we + * free the ack_ptr cell. That cell can however not be freed if the run + * length has increased: in this case we need to move the tail pointer + * backwards (towards higher indices), to its next-oldest neighbour. */ - avr = list_entry(av->av_records.next, struct dccp_ackvec_record, avr_node); - while (i--) { - const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; - u64 ackno_end_rl; + if (runlen_now > eff_runlen) { - dccp_set_seqno(&ackno_end_rl, *ackno - rl); + av->av_buf[avr->avr_ack_ptr] -= eff_runlen + 1; + av->av_buf_tail = __ackvec_idx_add(avr->avr_ack_ptr, 1); + /* This move may not have cleared the overflow flag. */ + if (av->av_overflow) + av->av_overflow = (av->av_buf_head == av->av_buf_tail); + } else { + av->av_buf_tail = avr->avr_ack_ptr; /* - * If our AVR sequence number is greater than the ack, go - * forward in the AVR list until it is not so. + * We have made sure that avr points to a valid cell within the + * buffer. This cell is either older than head, or equals head + * (empty buffer): in both cases we no longer have any overflow. */ - list_for_each_entry_from(avr, &av->av_records, avr_node) { - if (!after48(avr->avr_ack_seqno, *ackno)) - goto found; - } - /* End of the av_records list, not found, exit */ - break; -found: - if (between48(avr->avr_ack_seqno, ackno_end_rl, *ackno)) { - const u8 state = *vector & DCCP_ACKVEC_STATE_MASK; - if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) { - dccp_pr_debug("%s ACK vector 0, len=%d, " - "ack_seqno=%llu, ack_ackno=%llu, " - "ACKED!\n", - dccp_role(sk), len, - (unsigned long long) - avr->avr_ack_seqno, - (unsigned long long) - avr->avr_ack_ackno); - dccp_ackvec_throw_record(av, avr); - break; - } - /* - * If it wasn't received, continue scanning... we might - * find another one. - */ - } + av->av_overflow = 0; + } - dccp_set_seqno(ackno, ackno_end_rl - 1); - ++vector; + /* + * The peer has acknowledged up to and including ack_ackno. Hence the + * first packet in group (2) of 11.4.2 is the successor of ack_ackno. + */ + av->av_tail_ackno = ADD48(avr->avr_ack_ackno, 1); + +free_records: + list_for_each_entry_safe_from(avr, next, &av->av_records, avr_node) { + list_del(&avr->avr_node); + kmem_cache_free(dccp_ackvec_record_slab, avr); } } -int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, - u64 *ackno, const u8 opt, const u8 *value, const u8 len) +/* + * Routines to keep track of Ack Vectors received in an skb + */ +int dccp_ackvec_parsed_add(struct list_head *head, u8 *vec, u8 len, u8 nonce) { - if (len > DCCP_MAX_ACKVEC_OPT_LEN) - return -1; + struct dccp_ackvec_parsed *new = kmalloc(sizeof(*new), GFP_ATOMIC); + + if (new == NULL) + return -ENOBUFS; + new->vec = vec; + new->len = len; + new->nonce = nonce; - /* dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq, value, len); */ - dccp_ackvec_check_rcv_ackvector(dccp_sk(sk)->dccps_hc_rx_ackvec, sk, - ackno, len, value); + list_add_tail(&new->node, head); return 0; } +EXPORT_SYMBOL_GPL(dccp_ackvec_parsed_add); + +void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks) +{ + struct dccp_ackvec_parsed *cur, *next; + + list_for_each_entry_safe(cur, next, parsed_chunks, node) + kfree(cur); + INIT_LIST_HEAD(parsed_chunks); +} +EXPORT_SYMBOL_GPL(dccp_ackvec_parsed_cleanup); int __init dccp_ackvec_init(void) { @@ -449,10 +379,9 @@ int __init dccp_ackvec_init(void) if (dccp_ackvec_slab == NULL) goto out_err; - dccp_ackvec_record_slab = - kmem_cache_create("dccp_ackvec_record", - sizeof(struct dccp_ackvec_record), - 0, SLAB_HWCACHE_ALIGN, NULL); + dccp_ackvec_record_slab = kmem_cache_create("dccp_ackvec_record", + sizeof(struct dccp_ackvec_record), + 0, SLAB_HWCACHE_ALIGN, NULL); if (dccp_ackvec_record_slab == NULL) goto out_destroy_slab; diff --git a/net/dccp/ackvec.h b/net/dccp/ackvec.h index bcb64fb4acef..6cdca79a99f7 100644 --- a/net/dccp/ackvec.h +++ b/net/dccp/ackvec.h @@ -3,156 +3,134 @@ /* * net/dccp/ackvec.h * - * An implementation of the DCCP protocol + * An implementation of Ack Vectors for the DCCP protocol + * Copyright (c) 2007 University of Aberdeen, Scotland, UK * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com> - * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ +#include <linux/dccp.h> #include <linux/compiler.h> -#include <linux/ktime.h> #include <linux/list.h> #include <linux/types.h> -/* Read about the ECN nonce to see why it is 253 */ -#define DCCP_MAX_ACKVEC_OPT_LEN 253 -/* We can spread an ack vector across multiple options */ -#define DCCP_MAX_ACKVEC_LEN (DCCP_MAX_ACKVEC_OPT_LEN * 2) +/* + * Ack Vector buffer space is static, in multiples of %DCCP_SINGLE_OPT_MAXLEN, + * the maximum size of a single Ack Vector. Setting %DCCPAV_NUM_ACKVECS to 1 + * will be sufficient for most cases of low Ack Ratios, using a value of 2 gives + * more headroom if Ack Ratio is higher or when the sender acknowledges slowly. + * The maximum value is bounded by the u16 types for indices and functions. + */ +#define DCCPAV_NUM_ACKVECS 2 +#define DCCPAV_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * DCCPAV_NUM_ACKVECS) -#define DCCP_ACKVEC_STATE_RECEIVED 0 -#define DCCP_ACKVEC_STATE_ECN_MARKED (1 << 6) -#define DCCP_ACKVEC_STATE_NOT_RECEIVED (3 << 6) +/* Estimated minimum average Ack Vector length - used for updating MPS */ +#define DCCPAV_MIN_OPTLEN 16 -#define DCCP_ACKVEC_STATE_MASK 0xC0 /* 11000000 */ -#define DCCP_ACKVEC_LEN_MASK 0x3F /* 00111111 */ +/* Threshold for coping with large bursts of losses */ +#define DCCPAV_BURST_THRESH (DCCPAV_MAX_ACKVEC_LEN / 8) -/** struct dccp_ackvec - ack vector - * - * This data structure is the one defined in RFC 4340, Appendix A. - * - * @av_buf_head - circular buffer head - * @av_buf_tail - circular buffer tail - * @av_buf_ackno - ack # of the most recent packet acknowledgeable in the - * buffer (i.e. %av_buf_head) - * @av_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked - * by the buffer with State 0 - * - * Additionally, the HC-Receiver must keep some information about the - * Ack Vectors it has recently sent. For each packet sent carrying an - * Ack Vector, it remembers four variables: +enum dccp_ackvec_states { + DCCPAV_RECEIVED = 0x00, + DCCPAV_ECN_MARKED = 0x40, + DCCPAV_RESERVED = 0x80, + DCCPAV_NOT_RECEIVED = 0xC0 +}; +#define DCCPAV_MAX_RUNLEN 0x3F + +static inline u8 dccp_ackvec_runlen(const u8 *cell) +{ + return *cell & DCCPAV_MAX_RUNLEN; +} + +static inline u8 dccp_ackvec_state(const u8 *cell) +{ + return *cell & ~DCCPAV_MAX_RUNLEN; +} + +/** struct dccp_ackvec - Ack Vector main data structure * - * @av_records - list of dccp_ackvec_record - * @av_ack_nonce - the one-bit sum of the ECN Nonces for all State 0. + * This implements a fixed-size circular buffer within an array and is largely + * based on Appendix A of RFC 4340. * - * @av_time - the time in usecs - * @av_buf - circular buffer of acknowledgeable packets + * @av_buf: circular buffer storage area + * @av_buf_head: head index; begin of live portion in @av_buf + * @av_buf_tail: tail index; first index _after_ the live portion in @av_buf + * @av_buf_ackno: highest seqno of acknowledgeable packet recorded in @av_buf + * @av_tail_ackno: lowest seqno of acknowledgeable packet recorded in @av_buf + * @av_buf_nonce: ECN nonce sums, each covering subsequent segments of up to + * %DCCP_SINGLE_OPT_MAXLEN cells in the live portion of @av_buf + * @av_overflow: if 1 then buf_head == buf_tail indicates buffer wraparound + * @av_records: list of %dccp_ackvec_record (Ack Vectors sent previously) */ struct dccp_ackvec { - u64 av_buf_ackno; - struct list_head av_records; - ktime_t av_time; + u8 av_buf[DCCPAV_MAX_ACKVEC_LEN]; u16 av_buf_head; - u16 av_vec_len; - u8 av_buf_nonce; - u8 av_ack_nonce; - u8 av_buf[DCCP_MAX_ACKVEC_LEN]; + u16 av_buf_tail; + u64 av_buf_ackno:48; + u64 av_tail_ackno:48; + bool av_buf_nonce[DCCPAV_NUM_ACKVECS]; + u8 av_overflow:1; + struct list_head av_records; }; -/** struct dccp_ackvec_record - ack vector record +/** struct dccp_ackvec_record - Records information about sent Ack Vectors * - * ACK vector record as defined in Appendix A of spec. + * These list entries define the additional information which the HC-Receiver + * keeps about recently-sent Ack Vectors; again refer to RFC 4340, Appendix A. * - * The list is sorted by avr_ack_seqno + * @avr_node: the list node in @av_records + * @avr_ack_seqno: sequence number of the packet the Ack Vector was sent on + * @avr_ack_ackno: the Ack number that this record/Ack Vector refers to + * @avr_ack_ptr: pointer into @av_buf where this record starts + * @avr_ack_runlen: run length of @avr_ack_ptr at the time of sending + * @avr_ack_nonce: the sum of @av_buf_nonce's at the time this record was sent * - * @avr_node - node in av_records - * @avr_ack_seqno - sequence number of the packet this record was sent on - * @avr_ack_ackno - sequence number being acknowledged - * @avr_ack_ptr - pointer into av_buf where this record starts - * @avr_ack_nonce - av_ack_nonce at the time this record was sent - * @avr_sent_len - lenght of the record in av_buf + * The list as a whole is sorted in descending order by @avr_ack_seqno. */ struct dccp_ackvec_record { struct list_head avr_node; - u64 avr_ack_seqno; - u64 avr_ack_ackno; + u64 avr_ack_seqno:48; + u64 avr_ack_ackno:48; u16 avr_ack_ptr; - u16 avr_sent_len; - u8 avr_ack_nonce; + u8 avr_ack_runlen; + u8 avr_ack_nonce:1; }; -struct sock; -struct sk_buff; - -#ifdef CONFIG_IP_DCCP_ACKVEC -extern int dccp_ackvec_init(void); +extern int dccp_ackvec_init(void); extern void dccp_ackvec_exit(void); extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority); extern void dccp_ackvec_free(struct dccp_ackvec *av); -extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, - const u64 ackno, const u8 state); - -extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, - struct sock *sk, const u64 ackno); -extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, - u64 *ackno, const u8 opt, - const u8 *value, const u8 len); +extern void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb); +extern int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum); +extern void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno); +extern u16 dccp_ackvec_buflen(const struct dccp_ackvec *av); -extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb); - -static inline int dccp_ackvec_pending(const struct dccp_ackvec *av) -{ - return av->av_vec_len; -} -#else /* CONFIG_IP_DCCP_ACKVEC */ -static inline int dccp_ackvec_init(void) +static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av) { - return 0; + return av->av_overflow == 0 && av->av_buf_head == av->av_buf_tail; } -static inline void dccp_ackvec_exit(void) -{ -} - -static inline struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority) -{ - return NULL; -} - -static inline void dccp_ackvec_free(struct dccp_ackvec *av) -{ -} - -static inline int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, - const u64 ackno, const u8 state) -{ - return -1; -} - -static inline void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, - struct sock *sk, const u64 ackno) -{ -} - -static inline int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, - const u64 *ackno, const u8 opt, - const u8 *value, const u8 len) -{ - return -1; -} - -static inline int dccp_insert_option_ackvec(const struct sock *sk, - const struct sk_buff *skb) -{ - return -1; -} +/** + * struct dccp_ackvec_parsed - Record offsets of Ack Vectors in skb + * @vec: start of vector (offset into skb) + * @len: length of @vec + * @nonce: whether @vec had an ECN nonce of 0 or 1 + * @node: FIFO - arranged in descending order of ack_ackno + * This structure is used by CCIDs to access Ack Vectors in a received skb. + */ +struct dccp_ackvec_parsed { + u8 *vec, + len, + nonce:1; + struct list_head node; +}; -static inline int dccp_ackvec_pending(const struct dccp_ackvec *av) -{ - return 0; -} -#endif /* CONFIG_IP_DCCP_ACKVEC */ +extern int dccp_ackvec_parsed_add(struct list_head *head, + u8 *vec, u8 len, u8 nonce); +extern void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks); #endif /* _ACKVEC_H */ diff --git a/net/dccp/ccid.c b/net/dccp/ccid.c index 4809753d12ae..e3fb52b4f5c6 100644 --- a/net/dccp/ccid.c +++ b/net/dccp/ccid.c @@ -13,6 +13,13 @@ #include "ccid.h" +static u8 builtin_ccids[] = { + DCCPC_CCID2, /* CCID2 is supported by default */ +#if defined(CONFIG_IP_DCCP_CCID3) || defined(CONFIG_IP_DCCP_CCID3_MODULE) + DCCPC_CCID3, +#endif +}; + static struct ccid_operations *ccids[CCID_MAX]; #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) static atomic_t ccids_lockct = ATOMIC_INIT(0); @@ -86,6 +93,47 @@ static void ccid_kmem_cache_destroy(struct kmem_cache *slab) } } +/* check that up to @array_len members in @ccid_array are supported */ +bool ccid_support_check(u8 const *ccid_array, u8 array_len) +{ + u8 i, j, found; + + for (i = 0, found = 0; i < array_len; i++, found = 0) { + for (j = 0; !found && j < ARRAY_SIZE(builtin_ccids); j++) + found = (ccid_array[i] == builtin_ccids[j]); + if (!found) + return false; + } + return true; +} + +/** + * ccid_get_builtin_ccids - Provide copy of `builtin' CCID array + * @ccid_array: pointer to copy into + * @array_len: value to return length into + * This function allocates memory - caller must see that it is freed after use. + */ +int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len) +{ + *ccid_array = kmemdup(builtin_ccids, sizeof(builtin_ccids), gfp_any()); + if (*ccid_array == NULL) + return -ENOBUFS; + *array_len = ARRAY_SIZE(builtin_ccids); + return 0; +} + +int ccid_getsockopt_builtin_ccids(struct sock *sk, int len, + char __user *optval, int __user *optlen) +{ + if (len < sizeof(builtin_ccids)) + return -EINVAL; + + if (put_user(sizeof(builtin_ccids), optlen) || + copy_to_user(optval, builtin_ccids, sizeof(builtin_ccids))) + return -EFAULT; + return 0; +} + int ccid_register(struct ccid_operations *ccid_ops) { int err = -ENOBUFS; @@ -148,22 +196,41 @@ int ccid_unregister(struct ccid_operations *ccid_ops) EXPORT_SYMBOL_GPL(ccid_unregister); +/** + * ccid_request_module - Pre-load CCID module for later use + * This should be called only from process context (e.g. during connection + * setup) and is necessary for later calls to ccid_new (typically in software + * interrupt), so that it has the modules available when they are needed. + */ +static int ccid_request_module(u8 id) +{ + if (!in_atomic()) { + ccids_read_lock(); + if (ccids[id] == NULL) { + ccids_read_unlock(); + return request_module("net-dccp-ccid-%d", id); + } + ccids_read_unlock(); + } + return 0; +} + +int ccid_request_modules(u8 const *ccid_array, u8 array_len) +{ +#ifdef CONFIG_KMOD + while (array_len--) + if (ccid_request_module(ccid_array[array_len])) + return -1; +#endif + return 0; +} + struct ccid *ccid_new(unsigned char id, struct sock *sk, int rx, gfp_t gfp) { struct ccid_operations *ccid_ops; struct ccid *ccid = NULL; ccids_read_lock(); -#ifdef CONFIG_KMOD - if (ccids[id] == NULL) { - /* We only try to load if in process context */ - ccids_read_unlock(); - if (gfp & GFP_ATOMIC) - goto out; - request_module("net-dccp-ccid-%d", id); - ccids_read_lock(); - } -#endif ccid_ops = ccids[id]; if (ccid_ops == NULL) goto out_unlock; @@ -205,20 +272,6 @@ out_module_put: EXPORT_SYMBOL_GPL(ccid_new); -struct ccid *ccid_hc_rx_new(unsigned char id, struct sock *sk, gfp_t gfp) -{ - return ccid_new(id, sk, 1, gfp); -} - -EXPORT_SYMBOL_GPL(ccid_hc_rx_new); - -struct ccid *ccid_hc_tx_new(unsigned char id,struct sock *sk, gfp_t gfp) -{ - return ccid_new(id, sk, 0, gfp); -} - -EXPORT_SYMBOL_GPL(ccid_hc_tx_new); - static void ccid_delete(struct ccid *ccid, struct sock *sk, int rx) { struct ccid_operations *ccid_ops; diff --git a/net/dccp/ccid.h b/net/dccp/ccid.h index fdeae7b57319..d27054ba2159 100644 --- a/net/dccp/ccid.h +++ b/net/dccp/ccid.h @@ -60,22 +60,18 @@ struct ccid_operations { void (*ccid_hc_tx_exit)(struct sock *sk); void (*ccid_hc_rx_packet_recv)(struct sock *sk, struct sk_buff *skb); - int (*ccid_hc_rx_parse_options)(struct sock *sk, - unsigned char option, - unsigned char len, u16 idx, - unsigned char* value); + int (*ccid_hc_rx_parse_options)(struct sock *sk, u8 pkt, + u8 opt, u8 *val, u8 len); int (*ccid_hc_rx_insert_options)(struct sock *sk, struct sk_buff *skb); void (*ccid_hc_tx_packet_recv)(struct sock *sk, struct sk_buff *skb); - int (*ccid_hc_tx_parse_options)(struct sock *sk, - unsigned char option, - unsigned char len, u16 idx, - unsigned char* value); + int (*ccid_hc_tx_parse_options)(struct sock *sk, u8 pkt, + u8 opt, u8 *val, u8 len); int (*ccid_hc_tx_send_packet)(struct sock *sk, struct sk_buff *skb); void (*ccid_hc_tx_packet_sent)(struct sock *sk, - int more, unsigned int len); + unsigned int len); void (*ccid_hc_rx_get_info)(struct sock *sk, struct tcp_info *info); void (*ccid_hc_tx_get_info)(struct sock *sk, @@ -103,31 +99,78 @@ static inline void *ccid_priv(const struct ccid *ccid) return (void *)ccid->ccid_priv; } +extern bool ccid_support_check(u8 const *ccid_array, u8 array_len); +extern int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len); +extern int ccid_getsockopt_builtin_ccids(struct sock *sk, int len, + char __user *, int __user *); + +extern int ccid_request_modules(u8 const *ccid_array, u8 array_len); extern struct ccid *ccid_new(unsigned char id, struct sock *sk, int rx, gfp_t gfp); -extern struct ccid *ccid_hc_rx_new(unsigned char id, struct sock *sk, - gfp_t gfp); -extern struct ccid *ccid_hc_tx_new(unsigned char id, struct sock *sk, - gfp_t gfp); +static inline int ccid_get_current_rx_ccid(struct dccp_sock *dp) +{ + struct ccid *ccid = dp->dccps_hc_rx_ccid; + + if (ccid == NULL || ccid->ccid_ops == NULL) + return -1; + return ccid->ccid_ops->ccid_id; +} + +static inline int ccid_get_current_tx_ccid(struct dccp_sock *dp) +{ + struct ccid *ccid = dp->dccps_hc_tx_ccid; + + if (ccid == NULL || ccid->ccid_ops == NULL) + return -1; + return ccid->ccid_ops->ccid_id; +} extern void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk); extern void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk); +/* + * Congestion control of queued data packets via CCID decision. + * + * The TX CCID performs its congestion-control by indicating whether and when a + * queued packet may be sent, using the return code of ccid_hc_tx_send_packet(). + * The following modes are supported via the symbolic constants below: + * - timer-based pacing (CCID returns a delay value in milliseconds); + * - autonomous dequeueing (CCID internally schedules dccps_xmitlet). + */ + +enum ccid_dequeueing_decision { + CCID_PACKET_SEND_AT_ONCE = 0x00000, /* "green light": no delay */ + CCID_PACKET_DELAY_MAX = 0x0FFFF, /* maximum delay in msecs */ + CCID_PACKET_DELAY = 0x10000, /* CCID msec-delay mode */ + CCID_PACKET_WILL_DEQUEUE_LATER = 0x20000, /* CCID autonomous mode */ + CCID_PACKET_ERR = 0xF0000, /* error condition */ +}; + +static inline int ccid_packet_dequeue_eval(const int return_code) +{ + if (return_code < 0) + return CCID_PACKET_ERR; + if (return_code == 0) + return CCID_PACKET_SEND_AT_ONCE; + if (return_code <= CCID_PACKET_DELAY_MAX) + return CCID_PACKET_DELAY; + return return_code; +} + static inline int ccid_hc_tx_send_packet(struct ccid *ccid, struct sock *sk, struct sk_buff *skb) { - int rc = 0; if (ccid->ccid_ops->ccid_hc_tx_send_packet != NULL) - rc = ccid->ccid_ops->ccid_hc_tx_send_packet(sk, skb); - return rc; + return ccid->ccid_ops->ccid_hc_tx_send_packet(sk, skb); + return CCID_PACKET_SEND_AT_ONCE; } static inline void ccid_hc_tx_packet_sent(struct ccid *ccid, struct sock *sk, - int more, unsigned int len) + unsigned int len) { if (ccid->ccid_ops->ccid_hc_tx_packet_sent != NULL) - ccid->ccid_ops->ccid_hc_tx_packet_sent(sk, more, len); + ccid->ccid_ops->ccid_hc_tx_packet_sent(sk, len); } static inline void ccid_hc_rx_packet_recv(struct ccid *ccid, struct sock *sk, @@ -144,27 +187,31 @@ static inline void ccid_hc_tx_packet_recv(struct ccid *ccid, struct sock *sk, ccid->ccid_ops->ccid_hc_tx_packet_recv(sk, skb); } +/** + * ccid_hc_tx_parse_options - Parse CCID-specific options sent by the receiver + * @pkt: type of packet that @opt appears on (RFC 4340, 5.1) + * @opt: the CCID-specific option type (RFC 4340, 5.8 and 10.3) + * @val: value of @opt + * @len: length of @val in bytes + */ static inline int ccid_hc_tx_parse_options(struct ccid *ccid, struct sock *sk, - unsigned char option, - unsigned char len, u16 idx, - unsigned char* value) + u8 pkt, u8 opt, u8 *val, u8 len) { - int rc = 0; - if (ccid->ccid_ops->ccid_hc_tx_parse_options != NULL) - rc = ccid->ccid_ops->ccid_hc_tx_parse_options(sk, option, len, idx, - value); - return rc; + if (ccid->ccid_ops->ccid_hc_tx_parse_options == NULL) + return 0; + return ccid->ccid_ops->ccid_hc_tx_parse_options(sk, pkt, opt, val, len); } +/** + * ccid_hc_rx_parse_options - Parse CCID-specific options sent by the sender + * Arguments are analogous to ccid_hc_tx_parse_options() + */ static inline int ccid_hc_rx_parse_options(struct ccid *ccid, struct sock *sk, - unsigned char option, - unsigned char len, u16 idx, - unsigned char* value) + u8 pkt, u8 opt, u8 *val, u8 len) { - int rc = 0; - if (ccid->ccid_ops->ccid_hc_rx_parse_options != NULL) - rc = ccid->ccid_ops->ccid_hc_rx_parse_options(sk, option, len, idx, value); - return rc; + if (ccid->ccid_ops->ccid_hc_rx_parse_options == NULL) + return 0; + return ccid->ccid_ops->ccid_hc_rx_parse_options(sk, pkt, opt, val, len); } static inline int ccid_hc_rx_insert_options(struct ccid *ccid, struct sock *sk, diff --git a/net/dccp/ccids/Kconfig b/net/dccp/ccids/Kconfig index 12275943eab8..fb168be2cb43 100644 --- a/net/dccp/ccids/Kconfig +++ b/net/dccp/ccids/Kconfig @@ -1,10 +1,8 @@ menu "DCCP CCIDs Configuration (EXPERIMENTAL)" - depends on EXPERIMENTAL config IP_DCCP_CCID2 - tristate "CCID2 (TCP-Like) (EXPERIMENTAL)" + tristate "CCID2 (TCP-Like)" def_tristate IP_DCCP - select IP_DCCP_ACKVEC ---help--- CCID 2, TCP-like Congestion Control, denotes Additive Increase, Multiplicative Decrease (AIMD) congestion control with behavior @@ -36,7 +34,7 @@ config IP_DCCP_CCID2_DEBUG If in doubt, say N. config IP_DCCP_CCID3 - tristate "CCID3 (TCP-Friendly) (EXPERIMENTAL)" + tristate "CCID3 (TCP-Friendly)" def_tristate IP_DCCP select IP_DCCP_TFRC_LIB ---help--- @@ -64,9 +62,9 @@ config IP_DCCP_CCID3 If in doubt, say M. +if IP_DCCP_CCID3 config IP_DCCP_CCID3_DEBUG bool "CCID3 debugging messages" - depends on IP_DCCP_CCID3 ---help--- Enable CCID3-specific debugging messages. @@ -76,10 +74,29 @@ config IP_DCCP_CCID3_DEBUG If in doubt, say N. +choice + prompt "Select method for measuring the packet size s" + default IP_DCCP_CCID3_MEASURE_S_AS_MPS + +config IP_DCCP_CCID3_MEASURE_S_AS_MPS + bool "Always use MPS in place of s" + ---help--- + This use is recommended as it is consistent with the initialisation + of X and suggested when s varies (rfc3448bis, (1) in section 4.1). +config IP_DCCP_CCID3_MEASURE_S_AS_AVG + bool "Use moving average" + ---help--- + An alternative way of tracking s, also supported by rfc3448bis. + This used to be the default for CCID-3 in previous kernels. +config IP_DCCP_CCID3_MEASURE_S_AS_MAX + bool "Track the maximum payload length" + ---help--- + An experimental method based on tracking the maximum packet size. +endchoice + config IP_DCCP_CCID3_RTO int "Use higher bound for nofeedback timer" default 100 - depends on IP_DCCP_CCID3 && EXPERIMENTAL ---help--- Use higher lower bound for nofeedback timer expiration. @@ -106,6 +123,7 @@ config IP_DCCP_CCID3_RTO The purpose of the nofeedback timer is to slow DCCP down when there is serious network congestion: experimenting with larger values should therefore not be performed on WANs. +endif # IP_DCCP_CCID3 config IP_DCCP_TFRC_LIB tristate diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c index 9a430734530c..fa713227c66f 100644 --- a/net/dccp/ccids/ccid2.c +++ b/net/dccp/ccids/ccid2.c @@ -25,7 +25,7 @@ /* * This implementation should follow RFC 4341 */ - +#include "../feat.h" #include "../ccid.h" #include "../dccp.h" #include "ccid2.h" @@ -34,51 +34,8 @@ #ifdef CONFIG_IP_DCCP_CCID2_DEBUG static int ccid2_debug; #define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a) - -static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx) -{ - int len = 0; - int pipe = 0; - struct ccid2_seq *seqp = hctx->ccid2hctx_seqh; - - /* there is data in the chain */ - if (seqp != hctx->ccid2hctx_seqt) { - seqp = seqp->ccid2s_prev; - len++; - if (!seqp->ccid2s_acked) - pipe++; - - while (seqp != hctx->ccid2hctx_seqt) { - struct ccid2_seq *prev = seqp->ccid2s_prev; - - len++; - if (!prev->ccid2s_acked) - pipe++; - - /* packets are sent sequentially */ - BUG_ON(dccp_delta_seqno(seqp->ccid2s_seq, - prev->ccid2s_seq ) >= 0); - BUG_ON(time_before(seqp->ccid2s_sent, - prev->ccid2s_sent)); - - seqp = prev; - } - } - - BUG_ON(pipe != hctx->ccid2hctx_pipe); - ccid2_pr_debug("len of chain=%d\n", len); - - do { - seqp = seqp->ccid2s_prev; - len++; - } while (seqp != hctx->ccid2hctx_seqh); - - ccid2_pr_debug("total len=%d\n", len); - BUG_ON(len != hctx->ccid2hctx_seqbufc * CCID2_SEQBUF_LEN); -} #else #define ccid2_pr_debug(format, a...) -#define ccid2_hc_tx_check_sanity(hctx) #endif static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx) @@ -87,8 +44,7 @@ static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx) int i; /* check if we have space to preserve the pointer to the buffer */ - if (hctx->ccid2hctx_seqbufc >= (sizeof(hctx->ccid2hctx_seqbuf) / - sizeof(struct ccid2_seq*))) + if (hctx->seqbufc >= sizeof(hctx->seqbuf) / sizeof(struct ccid2_seq *)) return -ENOMEM; /* allocate buffer and initialize linked list */ @@ -104,38 +60,35 @@ static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx) seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1]; /* This is the first allocation. Initiate the head and tail. */ - if (hctx->ccid2hctx_seqbufc == 0) - hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqt = seqp; + if (hctx->seqbufc == 0) + hctx->seqh = hctx->seqt = seqp; else { /* link the existing list with the one we just created */ - hctx->ccid2hctx_seqh->ccid2s_next = seqp; - seqp->ccid2s_prev = hctx->ccid2hctx_seqh; + hctx->seqh->ccid2s_next = seqp; + seqp->ccid2s_prev = hctx->seqh; - hctx->ccid2hctx_seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1]; - seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hctx->ccid2hctx_seqt; + hctx->seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1]; + seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hctx->seqt; } /* store the original pointer to the buffer so we can free it */ - hctx->ccid2hctx_seqbuf[hctx->ccid2hctx_seqbufc] = seqp; - hctx->ccid2hctx_seqbufc++; + hctx->seqbuf[hctx->seqbufc] = seqp; + hctx->seqbufc++; return 0; } static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) { - struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); - - if (hctx->ccid2hctx_pipe < hctx->ccid2hctx_cwnd) - return 0; - - return 1; /* XXX CCID should dequeue when ready instead of polling */ + if (ccid2_cwnd_network_limited(ccid2_hc_tx_sk(sk))) + return CCID_PACKET_WILL_DEQUEUE_LATER; + return CCID_PACKET_SEND_AT_ONCE; } static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val) { struct dccp_sock *dp = dccp_sk(sk); - u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->ccid2hctx_cwnd, 2); + u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->cwnd, 2); /* * Ensure that Ack Ratio does not exceed ceil(cwnd/2), which is (2) from @@ -147,8 +100,8 @@ static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val) DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio); val = max_ratio; } - if (val > 0xFFFF) /* RFC 4340, 11.3 */ - val = 0xFFFF; + if (val > DCCPF_ACK_RATIO_MAX) + val = DCCPF_ACK_RATIO_MAX; if (val == dp->dccps_l_ack_ratio) return; @@ -157,99 +110,77 @@ static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val) dp->dccps_l_ack_ratio = val; } -static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hctx, long val) -{ - ccid2_pr_debug("change SRTT to %ld\n", val); - hctx->ccid2hctx_srtt = val; -} - -static void ccid2_start_rto_timer(struct sock *sk); - static void ccid2_hc_tx_rto_expire(unsigned long data) { struct sock *sk = (struct sock *)data; struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); - long s; + const bool sender_was_blocked = ccid2_cwnd_network_limited(hctx); bh_lock_sock(sk); if (sock_owned_by_user(sk)) { - sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer, - jiffies + HZ / 5); + sk_reset_timer(sk, &hctx->rtotimer, jiffies + HZ / 5); goto out; } ccid2_pr_debug("RTO_EXPIRE\n"); - ccid2_hc_tx_check_sanity(hctx); - /* back-off timer */ - hctx->ccid2hctx_rto <<= 1; - - s = hctx->ccid2hctx_rto / HZ; - if (s > 60) - hctx->ccid2hctx_rto = 60 * HZ; - - ccid2_start_rto_timer(sk); + hctx->rto <<= 1; + if (hctx->rto > DCCP_RTO_MAX) + hctx->rto = DCCP_RTO_MAX; /* adjust pipe, cwnd etc */ - hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd / 2; - if (hctx->ccid2hctx_ssthresh < 2) - hctx->ccid2hctx_ssthresh = 2; - hctx->ccid2hctx_cwnd = 1; - hctx->ccid2hctx_pipe = 0; + hctx->ssthresh = hctx->cwnd / 2; + if (hctx->ssthresh < 2) + hctx->ssthresh = 2; + hctx->cwnd = 1; + hctx->pipe = 0; /* clear state about stuff we sent */ - hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh; - hctx->ccid2hctx_packets_acked = 0; + hctx->seqt = hctx->seqh; + hctx->packets_acked = 0; /* clear ack ratio state. */ - hctx->ccid2hctx_rpseq = 0; - hctx->ccid2hctx_rpdupack = -1; + hctx->rpseq = 0; + hctx->rpdupack = -1; ccid2_change_l_ack_ratio(sk, 1); - ccid2_hc_tx_check_sanity(hctx); + + /* if we were blocked before, we may now send cwnd=1 packet */ + if (sender_was_blocked) + tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet); + /* restart backed-off timer */ + sk_reset_timer(sk, &hctx->rtotimer, jiffies + hctx->rto); out: bh_unlock_sock(sk); sock_put(sk); } -static void ccid2_start_rto_timer(struct sock *sk) -{ - struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); - - ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto); - - BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer)); - sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer, - jiffies + hctx->ccid2hctx_rto); -} - -static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len) +static void ccid2_hc_tx_packet_sent(struct sock *sk, unsigned int len) { struct dccp_sock *dp = dccp_sk(sk); struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); struct ccid2_seq *next; - hctx->ccid2hctx_pipe++; + hctx->pipe++; - hctx->ccid2hctx_seqh->ccid2s_seq = dp->dccps_gss; - hctx->ccid2hctx_seqh->ccid2s_acked = 0; - hctx->ccid2hctx_seqh->ccid2s_sent = jiffies; + hctx->seqh->ccid2s_seq = dp->dccps_gss; + hctx->seqh->ccid2s_acked = 0; + hctx->seqh->ccid2s_sent = jiffies; - next = hctx->ccid2hctx_seqh->ccid2s_next; + next = hctx->seqh->ccid2s_next; /* check if we need to alloc more space */ - if (next == hctx->ccid2hctx_seqt) { + if (next == hctx->seqt) { if (ccid2_hc_tx_alloc_seq(hctx)) { DCCP_CRIT("packet history - out of memory!"); /* FIXME: find a more graceful way to bail out */ return; } - next = hctx->ccid2hctx_seqh->ccid2s_next; - BUG_ON(next == hctx->ccid2hctx_seqt); + next = hctx->seqh->ccid2s_next; + BUG_ON(next == hctx->seqt); } - hctx->ccid2hctx_seqh = next; + hctx->seqh = next; - ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd, - hctx->ccid2hctx_pipe); + ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->cwnd, hctx->pipe); /* * FIXME: The code below is broken and the variables have been removed @@ -272,12 +203,12 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len) */ #if 0 /* Ack Ratio. Need to maintain a concept of how many windows we sent */ - hctx->ccid2hctx_arsent++; + hctx->arsent++; /* We had an ack loss in this window... */ - if (hctx->ccid2hctx_ackloss) { - if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) { - hctx->ccid2hctx_arsent = 0; - hctx->ccid2hctx_ackloss = 0; + if (hctx->ackloss) { + if (hctx->arsent >= hctx->cwnd) { + hctx->arsent = 0; + hctx->ackloss = 0; } } else { /* No acks lost up to now... */ @@ -287,28 +218,28 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len) int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio - dp->dccps_l_ack_ratio; - denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom; + denom = hctx->cwnd * hctx->cwnd / denom; - if (hctx->ccid2hctx_arsent >= denom) { + if (hctx->arsent >= denom) { ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1); - hctx->ccid2hctx_arsent = 0; + hctx->arsent = 0; } } else { /* we can't increase ack ratio further [1] */ - hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/ + hctx->arsent = 0; /* or maybe set it to cwnd*/ } } #endif /* setup RTO timer */ - if (!timer_pending(&hctx->ccid2hctx_rtotimer)) - ccid2_start_rto_timer(sk); + if (!timer_pending(&hctx->rtotimer)) + sk_reset_timer(sk, &hctx->rtotimer, jiffies + hctx->rto); #ifdef CONFIG_IP_DCCP_CCID2_DEBUG do { - struct ccid2_seq *seqp = hctx->ccid2hctx_seqt; + struct ccid2_seq *seqp = hctx->seqt; - while (seqp != hctx->ccid2hctx_seqh) { + while (seqp != hctx->seqh) { ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n", (unsigned long long)seqp->ccid2s_seq, seqp->ccid2s_acked, seqp->ccid2s_sent); @@ -316,205 +247,158 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len) } } while (0); ccid2_pr_debug("=========\n"); - ccid2_hc_tx_check_sanity(hctx); #endif } -/* XXX Lame code duplication! - * returns -1 if none was found. - * else returns the next offset to use in the function call. +/** + * ccid2_rtt_estimator - Sample RTT and compute RTO using RFC2988 algorithm + * This code is almost identical with TCP's tcp_rtt_estimator(), since + * - it has a higher sampling frequency (recommended by RFC 1323), + * - the RTO does not collapse into RTT due to RTTVAR going towards zero, + * - it is simple (cf. more complex proposals such as Eifel timer or research + * which suggests that the gain should be set according to window size), + * - in tests it was found to work well with CCID2 [gerrit]. */ -static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset, - unsigned char **vec, unsigned char *veclen) +static void ccid2_rtt_estimator(struct sock *sk, const long mrtt) { - const struct dccp_hdr *dh = dccp_hdr(skb); - unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); - unsigned char *opt_ptr; - const unsigned char *opt_end = (unsigned char *)dh + - (dh->dccph_doff * 4); - unsigned char opt, len; - unsigned char *value; - - BUG_ON(offset < 0); - options += offset; - opt_ptr = options; - if (opt_ptr >= opt_end) - return -1; - - while (opt_ptr != opt_end) { - opt = *opt_ptr++; - len = 0; - value = NULL; - - /* Check if this isn't a single byte option */ - if (opt > DCCPO_MAX_RESERVED) { - if (opt_ptr == opt_end) - goto out_invalid_option; - - len = *opt_ptr++; - if (len < 3) - goto out_invalid_option; + struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); + long m = mrtt ? : 1; + + if (hctx->srtt == 0) { + /* First measurement m */ + hctx->srtt = m << 3; + hctx->mdev = m << 1; + + hctx->mdev_max = max(TCP_RTO_MIN, hctx->mdev); + hctx->rttvar = hctx->mdev_max; + hctx->rtt_seq = dccp_sk(sk)->dccps_gss; + } else { + /* Update scaled SRTT as SRTT += 1/8 * (m - SRTT) */ + m -= (hctx->srtt >> 3); + hctx->srtt += m; + + /* Similarly, update scaled mdev with regard to |m| */ + if (m < 0) { + m = -m; + m -= (hctx->mdev >> 2); /* - * Remove the type and len fields, leaving - * just the value size + * This neutralises RTO increase when RTT < SRTT - mdev + * (see P. Sarolahti, A. Kuznetsov,"Congestion Control + * in Linux TCP", USENIX 2002, pp. 49-62). */ - len -= 2; - value = opt_ptr; - opt_ptr += len; + if (m > 0) + m >>= 3; + } else { + m -= (hctx->mdev >> 2); + } + hctx->mdev += m; - if (opt_ptr > opt_end) - goto out_invalid_option; + if (hctx->mdev > hctx->mdev_max) { + hctx->mdev_max = hctx->mdev; + if (hctx->mdev_max > hctx->rttvar) + hctx->rttvar = hctx->mdev_max; } - switch (opt) { - case DCCPO_ACK_VECTOR_0: - case DCCPO_ACK_VECTOR_1: - *vec = value; - *veclen = len; - return offset + (opt_ptr - options); + /* + * Decay RTTVAR at most once per flight, exploiting that + * 1) pipe <= cwnd <= Sequence_Window = W (RFC 4340, 7.5.2) + * 2) AWL = GSS-W+1 <= GAR <= GSS (RFC 4340, 7.5.1) + * GAR is a useful bound for FlightSize = pipe, AWL is probably + * too low as it over-estimates pipe. + */ + if (after48(dccp_sk(sk)->dccps_gar, hctx->rtt_seq)) { + if (hctx->mdev_max < hctx->rttvar) + hctx->rttvar -= (hctx->rttvar - + hctx->mdev_max) >> 2; + hctx->rtt_seq = dccp_sk(sk)->dccps_gss; + hctx->mdev_max = TCP_RTO_MIN; } } - return -1; - -out_invalid_option: - DCCP_BUG("Invalid option - this should not happen (previous parsing)!"); - return -1; -} - -static void ccid2_hc_tx_kill_rto_timer(struct sock *sk) -{ - struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); + /* + * Set RTO from SRTT and RTTVAR + * Clock granularity is ignored since the minimum error for RTTVAR is + * clamped to 50msec (corresponding to HZ=20). This leads to a minimum + * RTO of 200msec. This agrees with TCP and RFC 4341, 5.: "Because DCCP + * does not retransmit data, DCCP does not require TCP's recommended + * minimum timeout of one second". + */ + hctx->rto = (hctx->srtt >> 3) + hctx->rttvar; - sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer); - ccid2_pr_debug("deleted RTO timer\n"); + if (hctx->rto > DCCP_RTO_MAX) + hctx->rto = DCCP_RTO_MAX; } -static inline void ccid2_new_ack(struct sock *sk, - struct ccid2_seq *seqp, - unsigned int *maxincr) +static void ccid2_new_ack(struct sock *sk, struct ccid2_seq *seqp, + unsigned int *maxincr) { struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); - if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) { - if (*maxincr > 0 && ++hctx->ccid2hctx_packets_acked == 2) { - hctx->ccid2hctx_cwnd += 1; - *maxincr -= 1; - hctx->ccid2hctx_packets_acked = 0; + if (hctx->cwnd < hctx->ssthresh) { + if (*maxincr > 0 && ++hctx->packets_acked == 2) { + hctx->cwnd += 1; + *maxincr -= 1; + hctx->packets_acked = 0; } - } else if (++hctx->ccid2hctx_packets_acked >= hctx->ccid2hctx_cwnd) { - hctx->ccid2hctx_cwnd += 1; - hctx->ccid2hctx_packets_acked = 0; + } else if (++hctx->packets_acked >= hctx->cwnd) { + hctx->cwnd += 1; + hctx->packets_acked = 0; } - - /* update RTO */ - if (hctx->ccid2hctx_srtt == -1 || - time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) { - unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent; - int s; - - /* first measurement */ - if (hctx->ccid2hctx_srtt == -1) { - ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n", - r, jiffies, - (unsigned long long)seqp->ccid2s_seq); - ccid2_change_srtt(hctx, r); - hctx->ccid2hctx_rttvar = r >> 1; - } else { - /* RTTVAR */ - long tmp = hctx->ccid2hctx_srtt - r; - long srtt; - - if (tmp < 0) - tmp *= -1; - - tmp >>= 2; - hctx->ccid2hctx_rttvar *= 3; - hctx->ccid2hctx_rttvar >>= 2; - hctx->ccid2hctx_rttvar += tmp; - - /* SRTT */ - srtt = hctx->ccid2hctx_srtt; - srtt *= 7; - srtt >>= 3; - tmp = r >> 3; - srtt += tmp; - ccid2_change_srtt(hctx, srtt); - } - s = hctx->ccid2hctx_rttvar << 2; - /* clock granularity is 1 when based on jiffies */ - if (!s) - s = 1; - hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s; - - /* must be at least a second */ - s = hctx->ccid2hctx_rto / HZ; - /* DCCP doesn't require this [but I like it cuz my code sux] */ -#if 1 - if (s < 1) - hctx->ccid2hctx_rto = HZ; -#endif - /* max 60 seconds */ - if (s > 60) - hctx->ccid2hctx_rto = HZ * 60; - - hctx->ccid2hctx_lastrtt = jiffies; - - ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n", - hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar, - hctx->ccid2hctx_rto, HZ, r); - } - - /* we got a new ack, so re-start RTO timer */ - ccid2_hc_tx_kill_rto_timer(sk); - ccid2_start_rto_timer(sk); -} - -static void ccid2_hc_tx_dec_pipe(struct sock *sk) -{ - struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); - - if (hctx->ccid2hctx_pipe == 0) - DCCP_BUG("pipe == 0"); - else - hctx->ccid2hctx_pipe--; - - if (hctx->ccid2hctx_pipe == 0) - ccid2_hc_tx_kill_rto_timer(sk); + /* + * FIXME: RTT is sampled several times per acknowledgment (for each + * entry in the Ack Vector), instead of once per Ack (as in TCP SACK). + * This causes the RTT to be over-estimated, since the older entries + * in the Ack Vector have earlier sending times. + * The cleanest solution is to not use the ccid2s_sent field at all + * and instead use DCCP timestamps - need to be resolved at some time. + */ + ccid2_rtt_estimator(sk, jiffies - seqp->ccid2s_sent); } static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp) { struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); - if (time_before(seqp->ccid2s_sent, hctx->ccid2hctx_last_cong)) { + if (time_before(seqp->ccid2s_sent, hctx->last_cong)) { ccid2_pr_debug("Multiple losses in an RTT---treating as one\n"); return; } - hctx->ccid2hctx_last_cong = jiffies; + hctx->last_cong = jiffies; - hctx->ccid2hctx_cwnd = hctx->ccid2hctx_cwnd / 2 ? : 1U; - hctx->ccid2hctx_ssthresh = max(hctx->ccid2hctx_cwnd, 2U); + hctx->cwnd = hctx->cwnd / 2 ? : 1U; + hctx->ssthresh = max(hctx->cwnd, 2U); /* Avoid spurious timeouts resulting from Ack Ratio > cwnd */ - if (dccp_sk(sk)->dccps_l_ack_ratio > hctx->ccid2hctx_cwnd) - ccid2_change_l_ack_ratio(sk, hctx->ccid2hctx_cwnd); + if (dccp_sk(sk)->dccps_l_ack_ratio > hctx->cwnd) + ccid2_change_l_ack_ratio(sk, hctx->cwnd); +} + +static int ccid2_hc_tx_parse_options(struct sock *sk, u8 packet_type, + u8 option, u8 *optval, u8 optlen) +{ + struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); + + switch (option) { + case DCCPO_ACK_VECTOR_0: + case DCCPO_ACK_VECTOR_1: + return dccp_ackvec_parsed_add(&hctx->av_chunks, optval, optlen, + option - DCCPO_ACK_VECTOR_0); + } + return 0; } static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) { struct dccp_sock *dp = dccp_sk(sk); struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); + const bool sender_was_blocked = ccid2_cwnd_network_limited(hctx); + struct dccp_ackvec_parsed *avp; u64 ackno, seqno; struct ccid2_seq *seqp; - unsigned char *vector; - unsigned char veclen; - int offset = 0; int done = 0; unsigned int maxincr = 0; - ccid2_hc_tx_check_sanity(hctx); /* check reverse path congestion */ seqno = DCCP_SKB_CB(skb)->dccpd_seq; @@ -523,21 +407,21 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) * -sorbo. */ /* need to bootstrap */ - if (hctx->ccid2hctx_rpdupack == -1) { - hctx->ccid2hctx_rpdupack = 0; - hctx->ccid2hctx_rpseq = seqno; + if (hctx->rpdupack == -1) { + hctx->rpdupack = 0; + hctx->rpseq = seqno; } else { /* check if packet is consecutive */ - if (dccp_delta_seqno(hctx->ccid2hctx_rpseq, seqno) == 1) - hctx->ccid2hctx_rpseq = seqno; + if (dccp_delta_seqno(hctx->rpseq, seqno) == 1) + hctx->rpseq = seqno; /* it's a later packet */ - else if (after48(seqno, hctx->ccid2hctx_rpseq)) { - hctx->ccid2hctx_rpdupack++; + else if (after48(seqno, hctx->rpseq)) { + hctx->rpdupack++; /* check if we got enough dupacks */ - if (hctx->ccid2hctx_rpdupack >= NUMDUPACK) { - hctx->ccid2hctx_rpdupack = -1; /* XXX lame */ - hctx->ccid2hctx_rpseq = 0; + if (hctx->rpdupack >= NUMDUPACK) { + hctx->rpdupack = -1; /* XXX lame */ + hctx->rpseq = 0; ccid2_change_l_ack_ratio(sk, 2 * dp->dccps_l_ack_ratio); } @@ -545,27 +429,22 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) } /* check forward path congestion */ - /* still didn't send out new data packets */ - if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt) + if (dccp_packet_without_ack(skb)) return; - switch (DCCP_SKB_CB(skb)->dccpd_type) { - case DCCP_PKT_ACK: - case DCCP_PKT_DATAACK: - break; - default: - return; - } + /* still didn't send out new data packets */ + if (hctx->seqh == hctx->seqt) + goto done; ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; - if (after48(ackno, hctx->ccid2hctx_high_ack)) - hctx->ccid2hctx_high_ack = ackno; + if (after48(ackno, hctx->high_ack)) + hctx->high_ack = ackno; - seqp = hctx->ccid2hctx_seqt; + seqp = hctx->seqt; while (before48(seqp->ccid2s_seq, ackno)) { seqp = seqp->ccid2s_next; - if (seqp == hctx->ccid2hctx_seqh) { - seqp = hctx->ccid2hctx_seqh->ccid2s_prev; + if (seqp == hctx->seqh) { + seqp = hctx->seqh->ccid2s_prev; break; } } @@ -575,26 +454,26 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) * packets per acknowledgement. Rounding up avoids that cwnd is not * advanced when Ack Ratio is 1 and gives a slight edge otherwise. */ - if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) + if (hctx->cwnd < hctx->ssthresh) maxincr = DIV_ROUND_UP(dp->dccps_l_ack_ratio, 2); /* go through all ack vectors */ - while ((offset = ccid2_ackvector(sk, skb, offset, - &vector, &veclen)) != -1) { + list_for_each_entry(avp, &hctx->av_chunks, node) { /* go through this ack vector */ - while (veclen--) { - const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; - u64 ackno_end_rl = SUB48(ackno, rl); + for (; avp->len--; avp->vec++) { + u64 ackno_end_rl = SUB48(ackno, + dccp_ackvec_runlen(avp->vec)); - ccid2_pr_debug("ackvec start:%llu end:%llu\n", + ccid2_pr_debug("ackvec %llu |%u,%u|\n", (unsigned long long)ackno, - (unsigned long long)ackno_end_rl); + dccp_ackvec_state(avp->vec) >> 6, + dccp_ackvec_runlen(avp->vec)); /* if the seqno we are analyzing is larger than the * current ackno, then move towards the tail of our * seqnos. */ while (after48(seqp->ccid2s_seq, ackno)) { - if (seqp == hctx->ccid2hctx_seqt) { + if (seqp == hctx->seqt) { done = 1; break; } @@ -607,26 +486,24 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) * run length */ while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) { - const u8 state = *vector & - DCCP_ACKVEC_STATE_MASK; + const u8 state = dccp_ackvec_state(avp->vec); /* new packet received or marked */ - if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED && + if (state != DCCPAV_NOT_RECEIVED && !seqp->ccid2s_acked) { - if (state == - DCCP_ACKVEC_STATE_ECN_MARKED) { + if (state == DCCPAV_ECN_MARKED) ccid2_congestion_event(sk, seqp); - } else + else ccid2_new_ack(sk, seqp, &maxincr); seqp->ccid2s_acked = 1; ccid2_pr_debug("Got ack for %llu\n", (unsigned long long)seqp->ccid2s_seq); - ccid2_hc_tx_dec_pipe(sk); + hctx->pipe--; } - if (seqp == hctx->ccid2hctx_seqt) { + if (seqp == hctx->seqt) { done = 1; break; } @@ -636,7 +513,6 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) break; ackno = SUB48(ackno_end_rl, 1); - vector++; } if (done) break; @@ -645,11 +521,11 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) /* The state about what is acked should be correct now * Check for NUMDUPACK */ - seqp = hctx->ccid2hctx_seqt; - while (before48(seqp->ccid2s_seq, hctx->ccid2hctx_high_ack)) { + seqp = hctx->seqt; + while (before48(seqp->ccid2s_seq, hctx->high_ack)) { seqp = seqp->ccid2s_next; - if (seqp == hctx->ccid2hctx_seqh) { - seqp = hctx->ccid2hctx_seqh->ccid2s_prev; + if (seqp == hctx->seqh) { + seqp = hctx->seqh->ccid2s_prev; break; } } @@ -660,7 +536,7 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) if (done == NUMDUPACK) break; } - if (seqp == hctx->ccid2hctx_seqt) + if (seqp == hctx->seqt) break; seqp = seqp->ccid2s_prev; } @@ -681,25 +557,34 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) * one ack vector. */ ccid2_congestion_event(sk, seqp); - ccid2_hc_tx_dec_pipe(sk); + hctx->pipe--; } - if (seqp == hctx->ccid2hctx_seqt) + if (seqp == hctx->seqt) break; seqp = seqp->ccid2s_prev; } - hctx->ccid2hctx_seqt = last_acked; + hctx->seqt = last_acked; } /* trim acked packets in tail */ - while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) { - if (!hctx->ccid2hctx_seqt->ccid2s_acked) + while (hctx->seqt != hctx->seqh) { + if (!hctx->seqt->ccid2s_acked) break; - hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next; + hctx->seqt = hctx->seqt->ccid2s_next; } - ccid2_hc_tx_check_sanity(hctx); + /* restart RTO timer if not all outstanding data has been acked */ + if (hctx->pipe == 0) + sk_stop_timer(sk, &hctx->rtotimer); + else + sk_reset_timer(sk, &hctx->rtotimer, jiffies + hctx->rto); +done: + /* check if incoming Acks allow pending packets to be sent */ + if (sender_was_blocked && !ccid2_cwnd_network_limited(hctx)) + tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet); + dccp_ackvec_parsed_cleanup(&hctx->av_chunks); } static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) @@ -709,17 +594,13 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) u32 max_ratio; /* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */ - hctx->ccid2hctx_ssthresh = ~0U; + hctx->ssthresh = ~0U; - /* - * RFC 4341, 5: "The cwnd parameter is initialized to at most four - * packets for new connections, following the rules from [RFC3390]". - * We need to convert the bytes of RFC3390 into the packets of RFC 4341. - */ - hctx->ccid2hctx_cwnd = clamp(4380U / dp->dccps_mss_cache, 2U, 4U); + /* Use larger initial windows (RFC 3390, rfc2581bis) */ + hctx->cwnd = rfc3390_bytes_to_packets(dp->dccps_mss_cache); /* Make sure that Ack Ratio is enabled and within bounds. */ - max_ratio = DIV_ROUND_UP(hctx->ccid2hctx_cwnd, 2); + max_ratio = DIV_ROUND_UP(hctx->cwnd, 2); if (dp->dccps_l_ack_ratio == 0 || dp->dccps_l_ack_ratio > max_ratio) dp->dccps_l_ack_ratio = max_ratio; @@ -727,15 +608,11 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) if (ccid2_hc_tx_alloc_seq(hctx)) return -ENOMEM; - hctx->ccid2hctx_rto = 3 * HZ; - ccid2_change_srtt(hctx, -1); - hctx->ccid2hctx_rttvar = -1; - hctx->ccid2hctx_rpdupack = -1; - hctx->ccid2hctx_last_cong = jiffies; - setup_timer(&hctx->ccid2hctx_rtotimer, ccid2_hc_tx_rto_expire, - (unsigned long)sk); - - ccid2_hc_tx_check_sanity(hctx); + hctx->rto = DCCP_TIMEOUT_INIT; + hctx->rpdupack = -1; + hctx->last_cong = jiffies; + setup_timer(&hctx->rtotimer, ccid2_hc_tx_rto_expire, (unsigned long)sk); + INIT_LIST_HEAD(&hctx->av_chunks); return 0; } @@ -744,11 +621,11 @@ static void ccid2_hc_tx_exit(struct sock *sk) struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); int i; - ccid2_hc_tx_kill_rto_timer(sk); + sk_stop_timer(sk, &hctx->rtotimer); - for (i = 0; i < hctx->ccid2hctx_seqbufc; i++) - kfree(hctx->ccid2hctx_seqbuf[i]); - hctx->ccid2hctx_seqbufc = 0; + for (i = 0; i < hctx->seqbufc; i++) + kfree(hctx->seqbuf[i]); + hctx->seqbufc = 0; } static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) @@ -759,27 +636,28 @@ static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) switch (DCCP_SKB_CB(skb)->dccpd_type) { case DCCP_PKT_DATA: case DCCP_PKT_DATAACK: - hcrx->ccid2hcrx_data++; - if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) { + hcrx->data++; + if (hcrx->data >= dp->dccps_r_ack_ratio) { dccp_send_ack(sk); - hcrx->ccid2hcrx_data = 0; + hcrx->data = 0; } break; } } static struct ccid_operations ccid2 = { - .ccid_id = DCCPC_CCID2, - .ccid_name = "TCP-like", - .ccid_owner = THIS_MODULE, - .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock), - .ccid_hc_tx_init = ccid2_hc_tx_init, - .ccid_hc_tx_exit = ccid2_hc_tx_exit, - .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet, - .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent, - .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv, - .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock), - .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv, + .ccid_id = DCCPC_CCID2, + .ccid_name = "TCP-like", + .ccid_owner = THIS_MODULE, + .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock), + .ccid_hc_tx_init = ccid2_hc_tx_init, + .ccid_hc_tx_exit = ccid2_hc_tx_exit, + .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet, + .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent, + .ccid_hc_tx_parse_options = ccid2_hc_tx_parse_options, + .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv, + .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock), + .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv, }; #ifdef CONFIG_IP_DCCP_CCID2_DEBUG diff --git a/net/dccp/ccids/ccid2.h b/net/dccp/ccids/ccid2.h index 2c94ca029010..8b7a2dee2f6d 100644 --- a/net/dccp/ccids/ccid2.h +++ b/net/dccp/ccids/ccid2.h @@ -42,34 +42,49 @@ struct ccid2_seq { /** struct ccid2_hc_tx_sock - CCID2 TX half connection * - * @ccid2hctx_{cwnd,ssthresh,pipe}: as per RFC 4341, section 5 - * @ccid2hctx_packets_acked - Ack counter for deriving cwnd growth (RFC 3465) - * @ccid2hctx_lastrtt -time RTT was last measured - * @ccid2hctx_rpseq - last consecutive seqno - * @ccid2hctx_rpdupack - dupacks since rpseq -*/ + * @{cwnd,ssthresh,pipe}: as per RFC 4341, section 5 + * @packets_acked: Ack counter for deriving cwnd growth (RFC 3465) + * @srtt: smoothed RTT estimate, scaled by 2^3 + * @mdev: smoothed RTT variation, scaled by 2^2 + * @mdev_max: maximum of @mdev during one flight + * @rttvar: moving average/maximum of @mdev_max + * @rto: RTO value deriving from SRTT and RTTVAR (RFC 2988) + * @rtt_seq: to decay RTTVAR at most once per flight + * @rpseq: last consecutive seqno + * @rpdupack: dupacks since rpseq + * @av_chunks: list of Ack Vectors received on current skb + */ struct ccid2_hc_tx_sock { - u32 ccid2hctx_cwnd; - u32 ccid2hctx_ssthresh; - u32 ccid2hctx_pipe; - u32 ccid2hctx_packets_acked; - struct ccid2_seq *ccid2hctx_seqbuf[CCID2_SEQBUF_MAX]; - int ccid2hctx_seqbufc; - struct ccid2_seq *ccid2hctx_seqh; - struct ccid2_seq *ccid2hctx_seqt; - long ccid2hctx_rto; - long ccid2hctx_srtt; - long ccid2hctx_rttvar; - unsigned long ccid2hctx_lastrtt; - struct timer_list ccid2hctx_rtotimer; - u64 ccid2hctx_rpseq; - int ccid2hctx_rpdupack; - unsigned long ccid2hctx_last_cong; - u64 ccid2hctx_high_ack; + u32 cwnd; + u32 ssthresh; + u32 pipe; + u32 packets_acked; + struct ccid2_seq *seqbuf[CCID2_SEQBUF_MAX]; + int seqbufc; + struct ccid2_seq *seqh; + struct ccid2_seq *seqt; + /* RTT measurement: variables/principles are the same as in TCP */ + u32 srtt, + mdev, + mdev_max, + rttvar, + rto; + u64 rtt_seq:48; + struct timer_list rtotimer; + u64 rpseq; + int rpdupack; + unsigned long last_cong; + u64 high_ack; + struct list_head av_chunks; }; +static inline bool ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock *hctx) +{ + return (hctx->pipe >= hctx->cwnd); +} + struct ccid2_hc_rx_sock { - int ccid2hcrx_data; + int data; }; static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk) diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c index 3b8bd7ca6761..06cfdad84a6a 100644 --- a/net/dccp/ccids/ccid3.c +++ b/net/dccp/ccids/ccid3.c @@ -49,75 +49,41 @@ static int ccid3_debug; /* * Transmitter Half-Connection Routines */ -#ifdef CONFIG_IP_DCCP_CCID3_DEBUG -static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state) -{ - static char *ccid3_state_names[] = { - [TFRC_SSTATE_NO_SENT] = "NO_SENT", - [TFRC_SSTATE_NO_FBACK] = "NO_FBACK", - [TFRC_SSTATE_FBACK] = "FBACK", - [TFRC_SSTATE_TERM] = "TERM", - }; - - return ccid3_state_names[state]; -} -#endif - -static void ccid3_hc_tx_set_state(struct sock *sk, - enum ccid3_hc_tx_states state) -{ - struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); - enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_state; - - ccid3_pr_debug("%s(%p) %-8.8s -> %s\n", - dccp_role(sk), sk, ccid3_tx_state_name(oldstate), - ccid3_tx_state_name(state)); - WARN_ON(state == oldstate); - hctx->ccid3hctx_state = state; -} +/* Oscillation Prevention/Reduction: recommended by rfc3448bis, on by default */ +static int do_osc_prev = true; /* * Compute the initial sending rate X_init in the manner of RFC 3390: * - * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT + * X_init = min(4 * MPS, max(2 * MPS, 4380 bytes)) / RTT * - * Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis - * (rev-02) clarifies the use of RFC 3390 with regard to the above formula. * For consistency with other parts of the code, X_init is scaled by 2^6. */ static inline u64 rfc3390_initial_rate(struct sock *sk) { - const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); - const __u32 w_init = clamp_t(__u32, 4380U, - 2 * hctx->ccid3hctx_s, 4 * hctx->ccid3hctx_s); + const u32 mps = dccp_sk(sk)->dccps_mss_cache, + w_init = clamp(4380U, 2 * mps, 4 * mps); - return scaled_div(w_init << 6, hctx->ccid3hctx_rtt); + return scaled_div(w_init << 6, ccid3_hc_tx_sk(sk)->rtt); } -/* - * Recalculate t_ipi and delta (should be called whenever X changes) +/** + * ccid3_update_send_interval - Calculate new t_ipi = s / X + * This respects the granularity of X (64 * bytes/second) and enforces the + * scaled minimum of s * 64 / t_mbi = `s' bytes/second as per RFC 3448/4342. */ static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hctx) { - /* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */ - hctx->ccid3hctx_t_ipi = scaled_div32(((u64)hctx->ccid3hctx_s) << 6, - hctx->ccid3hctx_x); - - /* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */ - hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2, - TFRC_OPSYS_HALF_TIME_GRAN); - - ccid3_pr_debug("t_ipi=%u, delta=%u, s=%u, X=%u\n", - hctx->ccid3hctx_t_ipi, hctx->ccid3hctx_delta, - hctx->ccid3hctx_s, (unsigned)(hctx->ccid3hctx_x >> 6)); - + if (unlikely(hctx->x <= hctx->s)) + hctx->x = hctx->s; + hctx->t_ipi = scaled_div32(((u64)hctx->s) << 6, hctx->x); } static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hctx, ktime_t now) { - u32 delta = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count); + u32 delta = ktime_us_delta(now, hctx->t_last_win_count); - return delta / hctx->ccid3hctx_rtt; + return delta / hctx->rtt; } /** @@ -133,8 +99,8 @@ static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hctx, ktime_t now) static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp) { struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); - __u64 min_rate = 2 * hctx->ccid3hctx_x_recv; - const __u64 old_x = hctx->ccid3hctx_x; + u64 min_rate = 2 * hctx->x_recv; + const u64 old_x = hctx->x; ktime_t now = stamp ? *stamp : ktime_get_real(); /* @@ -145,50 +111,44 @@ static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp) */ if (ccid3_hc_tx_idle_rtt(hctx, now) >= 2) { min_rate = rfc3390_initial_rate(sk); - min_rate = max(min_rate, 2 * hctx->ccid3hctx_x_recv); + min_rate = max(min_rate, 2 * hctx->x_recv); } - if (hctx->ccid3hctx_p > 0) { + if (hctx->p > 0) { - hctx->ccid3hctx_x = min(((__u64)hctx->ccid3hctx_x_calc) << 6, - min_rate); - hctx->ccid3hctx_x = max(hctx->ccid3hctx_x, - (((__u64)hctx->ccid3hctx_s) << 6) / - TFRC_T_MBI); + hctx->x = min(((u64)hctx->x_calc) << 6, min_rate); - } else if (ktime_us_delta(now, hctx->ccid3hctx_t_ld) - - (s64)hctx->ccid3hctx_rtt >= 0) { + } else if (ktime_us_delta(now, hctx->t_ld) - (s64)hctx->rtt >= 0) { - hctx->ccid3hctx_x = min(2 * hctx->ccid3hctx_x, min_rate); - hctx->ccid3hctx_x = max(hctx->ccid3hctx_x, - scaled_div(((__u64)hctx->ccid3hctx_s) << 6, - hctx->ccid3hctx_rtt)); - hctx->ccid3hctx_t_ld = now; + hctx->x = min(2 * hctx->x, min_rate); + hctx->x = max(hctx->x, + scaled_div(((u64)hctx->s) << 6, hctx->rtt)); + hctx->t_ld = now; } - if (hctx->ccid3hctx_x != old_x) { + if (hctx->x != old_x) { ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, " "X_recv=%u\n", (unsigned)(old_x >> 6), - (unsigned)(hctx->ccid3hctx_x >> 6), - hctx->ccid3hctx_x_calc, - (unsigned)(hctx->ccid3hctx_x_recv >> 6)); + (unsigned)(hctx->x >> 6), hctx->x_calc, + (unsigned)(hctx->x_recv >> 6)); ccid3_update_send_interval(hctx); } } /* - * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1) - * @len: DCCP packet payload size in bytes + * ccid3_hc_tx_measure_packet_size - Measuring the packet size `s' (sec 4.1) + * @new_len: DCCP payload size in bytes (not used by all methods) */ -static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len) +static u32 ccid3_hc_tx_measure_packet_size(struct sock *sk, const u16 new_len) { - const u16 old_s = hctx->ccid3hctx_s; - - hctx->ccid3hctx_s = tfrc_ewma(hctx->ccid3hctx_s, len, 9); - - if (hctx->ccid3hctx_s != old_s) - ccid3_update_send_interval(hctx); +#if defined(CONFIG_IP_DCCP_CCID3_MEASURE_S_AS_AVG) + return tfrc_ewma(ccid3_hc_tx_sk(sk)->s, new_len, 9); +#elif defined(CONFIG_IP_DCCP_CCID3_MEASURE_S_AS_MAX) + return max(ccid3_hc_tx_sk(sk)->s, new_len); +#else /* CONFIG_IP_DCCP_CCID3_MEASURE_S_AS_MPS */ + return dccp_sk(sk)->dccps_mss_cache; +#endif } /* @@ -198,13 +158,13 @@ static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len) static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx, ktime_t now) { - u32 delta = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count), - quarter_rtts = (4 * delta) / hctx->ccid3hctx_rtt; + u32 delta = ktime_us_delta(now, hctx->t_last_win_count), + quarter_rtts = (4 * delta) / hctx->rtt; if (quarter_rtts > 0) { - hctx->ccid3hctx_t_last_win_count = now; - hctx->ccid3hctx_last_win_count += min(quarter_rtts, 5U); - hctx->ccid3hctx_last_win_count &= 0xF; /* mod 16 */ + hctx->t_last_win_count = now; + hctx->last_win_count += min(quarter_rtts, 5U); + hctx->last_win_count &= 0xF; /* mod 16 */ } } @@ -221,25 +181,26 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data) goto restart_timer; } - ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk, - ccid3_tx_state_name(hctx->ccid3hctx_state)); + ccid3_pr_debug("%s(%p) entry with%s feedback\n", dccp_role(sk), sk, + hctx->feedback ? "" : "out"); - if (hctx->ccid3hctx_state == TFRC_SSTATE_FBACK) - ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); - else if (hctx->ccid3hctx_state != TFRC_SSTATE_NO_FBACK) + /* Ignore and do not restart after leaving the established state */ + if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN)) goto out; + /* Reset feedback state to "no feedback received" */ + hctx->feedback = false; + /* * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4 + * RTO is 0 if and only if no feedback has been received yet. */ - if (hctx->ccid3hctx_t_rto == 0 || /* no feedback received yet */ - hctx->ccid3hctx_p == 0) { + if (hctx->t_rto == 0 || hctx->p == 0) { /* halve send rate directly */ - hctx->ccid3hctx_x = max(hctx->ccid3hctx_x / 2, - (((__u64)hctx->ccid3hctx_s) << 6) / - TFRC_T_MBI); + hctx->x /= 2; ccid3_update_send_interval(hctx); + } else { /* * Modify the cached value of X_recv @@ -251,44 +212,41 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data) * * Note that X_recv is scaled by 2^6 while X_calc is not */ - BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc); + BUG_ON(hctx->p && !hctx->x_calc); - if (hctx->ccid3hctx_x_calc > (hctx->ccid3hctx_x_recv >> 5)) - hctx->ccid3hctx_x_recv = - max(hctx->ccid3hctx_x_recv / 2, - (((__u64)hctx->ccid3hctx_s) << 6) / - (2 * TFRC_T_MBI)); + if (hctx->x_calc > (hctx->x_recv >> 5)) + hctx->x_recv /= 2; else { - hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc; - hctx->ccid3hctx_x_recv <<= 4; + hctx->x_recv = hctx->x_calc; + hctx->x_recv <<= 4; } ccid3_hc_tx_update_x(sk, NULL); } ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n", - (unsigned long long)hctx->ccid3hctx_x); + (unsigned long long)hctx->x); /* * Set new timeout for the nofeedback timer. * See comments in packet_recv() regarding the value of t_RTO. */ - if (unlikely(hctx->ccid3hctx_t_rto == 0)) /* no feedback yet */ + if (unlikely(hctx->t_rto == 0)) /* no feedback received yet */ t_nfb = TFRC_INITIAL_TIMEOUT; else - t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi); + t_nfb = max(hctx->t_rto, 2 * hctx->t_ipi); restart_timer: - sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer, + sk_reset_timer(sk, &hctx->no_feedback_timer, jiffies + usecs_to_jiffies(t_nfb)); out: bh_unlock_sock(sk); sock_put(sk); } -/* - * returns - * > 0: delay (in msecs) that should pass before actually sending - * = 0: can send immediately - * < 0: error condition; do not send packet +/** + * ccid3_hc_tx_send_packet - Delay-based dequeueing of TX packets + * @skb: next packet candidate to send on @sk + * This function uses the convention of ccid_packet_dequeue_eval() and + * returns a millisecond-delay value between 0 and t_mbi = 64000 msec. */ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) { @@ -305,18 +263,14 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) if (unlikely(skb->len == 0)) return -EBADMSG; - switch (hctx->ccid3hctx_state) { - case TFRC_SSTATE_NO_SENT: - sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer, - (jiffies + + if (hctx->s == 0) { + sk_reset_timer(sk, &hctx->no_feedback_timer, (jiffies + usecs_to_jiffies(TFRC_INITIAL_TIMEOUT))); - hctx->ccid3hctx_last_win_count = 0; - hctx->ccid3hctx_t_last_win_count = now; + hctx->last_win_count = 0; + hctx->t_last_win_count = now; /* Set t_0 for initial packet */ - hctx->ccid3hctx_t_nom = now; - - hctx->ccid3hctx_s = skb->len; + hctx->t_nom = now; /* * Use initial RTT sample when available: recommended by erratum @@ -325,9 +279,9 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) */ if (dp->dccps_syn_rtt) { ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt); - hctx->ccid3hctx_rtt = dp->dccps_syn_rtt; - hctx->ccid3hctx_x = rfc3390_initial_rate(sk); - hctx->ccid3hctx_t_ld = now; + hctx->rtt = dp->dccps_syn_rtt; + hctx->x = rfc3390_initial_rate(sk); + hctx->t_ld = now; } else { /* * Sender does not have RTT sample: @@ -335,17 +289,20 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) * is needed in several parts (e.g. window counter); * - set sending rate X_pps = 1pps as per RFC 3448, 4.2. */ - hctx->ccid3hctx_rtt = DCCP_FALLBACK_RTT; - hctx->ccid3hctx_x = hctx->ccid3hctx_s; - hctx->ccid3hctx_x <<= 6; + hctx->rtt = DCCP_FALLBACK_RTT; + hctx->x = dp->dccps_mss_cache; + hctx->x <<= 6; } + + /* Compute t_ipi = s / X */ + hctx->s = ccid3_hc_tx_measure_packet_size(sk, skb->len); ccid3_update_send_interval(hctx); - ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); - break; - case TFRC_SSTATE_NO_FBACK: - case TFRC_SSTATE_FBACK: - delay = ktime_us_delta(hctx->ccid3hctx_t_nom, now); + /* Seed value for Oscillation Prevention (sec. 4.5) */ + hctx->r_sqmean = tfrc_scaled_sqrt(hctx->rtt); + + } else { + delay = ktime_us_delta(hctx->t_nom, now); ccid3_pr_debug("delay=%ld\n", (long)delay); /* * Scheduling of packet transmissions [RFC 3448, 4.6] @@ -355,99 +312,80 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) * else * // send the packet in (t_nom - t_now) milliseconds. */ - if (delay - (s64)hctx->ccid3hctx_delta >= 1000) - return (u32)delay / 1000L; + if (delay >= TFRC_T_DELTA) + return (u32)delay / USEC_PER_MSEC; ccid3_hc_tx_update_win_count(hctx, now); - break; - case TFRC_SSTATE_TERM: - DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk); - return -EINVAL; } /* prepare to send now (add options etc.) */ dp->dccps_hc_tx_insert_options = 1; - DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count; + DCCP_SKB_CB(skb)->dccpd_ccval = hctx->last_win_count; /* set the nominal send time for the next following packet */ - hctx->ccid3hctx_t_nom = ktime_add_us(hctx->ccid3hctx_t_nom, - hctx->ccid3hctx_t_ipi); - return 0; + hctx->t_nom = ktime_add_us(hctx->t_nom, hctx->t_ipi); + return CCID_PACKET_SEND_AT_ONCE; } -static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, - unsigned int len) +static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len) { struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); - ccid3_hc_tx_update_s(hctx, len); + /* Changes to s will become effective the next time X is computed */ + hctx->s = ccid3_hc_tx_measure_packet_size(sk, len); - if (tfrc_tx_hist_add(&hctx->ccid3hctx_hist, dccp_sk(sk)->dccps_gss)) + if (tfrc_tx_hist_add(&hctx->hist, dccp_sk(sk)->dccps_gss)) DCCP_CRIT("packet history - out of memory!"); } static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) { struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); - struct ccid3_options_received *opt_recv; + struct tfrc_tx_hist_entry *acked; ktime_t now; unsigned long t_nfb; - u32 pinv, r_sample; + u32 r_sample; /* we are only interested in ACKs */ if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK || DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK)) return; - /* ... and only in the established state */ - if (hctx->ccid3hctx_state != TFRC_SSTATE_FBACK && - hctx->ccid3hctx_state != TFRC_SSTATE_NO_FBACK) - return; - - opt_recv = &hctx->ccid3hctx_options_received; - now = ktime_get_real(); - - /* Estimate RTT from history if ACK number is valid */ - r_sample = tfrc_tx_hist_rtt(hctx->ccid3hctx_hist, - DCCP_SKB_CB(skb)->dccpd_ack_seq, now); - if (r_sample == 0) { - DCCP_WARN("%s(%p): %s with bogus ACK-%llu\n", dccp_role(sk), sk, - dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type), - (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq); + /* + * Locate the acknowledged packet in the TX history. + * + * Returning "entry not found" here can for instance happen when + * - the host has not sent out anything (e.g. a passive server), + * - the Ack is outdated (packet with higher Ack number was received), + * - it is a bogus Ack (for a packet not sent on this connection). + */ + acked = tfrc_tx_hist_find_entry(hctx->hist, dccp_hdr_ack_seq(skb)); + if (acked == NULL) return; - } + /* For the sake of RTT sampling, ignore/remove all older entries */ + tfrc_tx_hist_purge(&acked->next); - /* Update receive rate in units of 64 * bytes/second */ - hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate; - hctx->ccid3hctx_x_recv <<= 6; + /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */ + now = ktime_get_real(); + r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp)); + hctx->rtt = tfrc_ewma(hctx->rtt, r_sample, 9); - /* Update loss event rate (which is scaled by 1e6) */ - pinv = opt_recv->ccid3or_loss_event_rate; - if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */ - hctx->ccid3hctx_p = 0; - else /* can not exceed 100% */ - hctx->ccid3hctx_p = scaled_div(1, pinv); - /* - * Validate new RTT sample and update moving average - */ - r_sample = dccp_sample_rtt(sk, r_sample); - hctx->ccid3hctx_rtt = tfrc_ewma(hctx->ccid3hctx_rtt, r_sample, 9); /* * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3 */ - if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) { - ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK); + if (!hctx->feedback) { + hctx->feedback = true; - if (hctx->ccid3hctx_t_rto == 0) { + if (hctx->t_rto == 0) { /* * Initial feedback packet: Larger Initial Windows (4.2) */ - hctx->ccid3hctx_x = rfc3390_initial_rate(sk); - hctx->ccid3hctx_t_ld = now; + hctx->x = rfc3390_initial_rate(sk); + hctx->t_ld = now; ccid3_update_send_interval(hctx); goto done_computing_x; - } else if (hctx->ccid3hctx_p == 0) { + } else if (hctx->p == 0) { /* * First feedback after nofeedback timer expiry (4.3) */ @@ -456,25 +394,52 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) } /* Update sending rate (step 4 of [RFC 3448, 4.3]) */ - if (hctx->ccid3hctx_p > 0) - hctx->ccid3hctx_x_calc = - tfrc_calc_x(hctx->ccid3hctx_s, - hctx->ccid3hctx_rtt, - hctx->ccid3hctx_p); + if (hctx->p > 0) + hctx->x_calc = tfrc_calc_x(hctx->s, hctx->rtt, hctx->p); ccid3_hc_tx_update_x(sk, &now); done_computing_x: ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, " "p=%u, X_calc=%u, X_recv=%u, X=%u\n", - dccp_role(sk), - sk, hctx->ccid3hctx_rtt, r_sample, - hctx->ccid3hctx_s, hctx->ccid3hctx_p, - hctx->ccid3hctx_x_calc, - (unsigned)(hctx->ccid3hctx_x_recv >> 6), - (unsigned)(hctx->ccid3hctx_x >> 6)); + dccp_role(sk), sk, hctx->rtt, r_sample, + hctx->s, hctx->p, hctx->x_calc, + (unsigned)(hctx->x_recv >> 6), + (unsigned)(hctx->x >> 6)); + /* + * Oscillation Reduction (RFC 3448, 4.5) - modifying t_ipi according to + * RTT changes, multiplying by X/X_inst = sqrt(R_sample)/R_sqmean. This + * can be useful if few connections share a link, avoiding that buffer + * fill levels (RTT) oscillate as a result of frequent adjustments to X. + * A useful presentation with background information is in + * Joerg Widmer, "Equation-Based Congestion Control", + * MSc Thesis, University of Mannheim, Germany, 2000 + * (sec. 3.6.4), who calls this ISM ("Inter-packet Space Modulation"). + */ + if (do_osc_prev) { + r_sample = tfrc_scaled_sqrt(r_sample); + /* + * The modulation can work in both ways: increase/decrease t_ipi + * according to long-term increases/decreases of the RTT. The + * former is a useful measure, since it works against queue + * build-up. The latter temporarily increases the sending rate, + * so that buffers fill up more quickly. This in turn causes + * the RTT to increase, so that either later reduction becomes + * necessary or the RTT stays at a very high level. Decreasing + * t_ipi is therefore not supported. + * Furthermore, during the initial slow-start phase the RTT + * naturally increases, where using the algorithm would cause + * delays. Hence it is disabled during the initial slow-start. + */ + if (r_sample > hctx->r_sqmean && hctx->p > 0) + hctx->t_ipi = div_u64((u64)hctx->t_ipi * (u64)r_sample, + hctx->r_sqmean); + hctx->t_ipi = min_t(u32, hctx->t_ipi, TFRC_T_MBI); + /* update R_sqmean _after_ computing the modulation factor */ + hctx->r_sqmean = tfrc_ewma(hctx->r_sqmean, r_sample, 9); + } /* unschedule no feedback timer */ - sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer); + sk_stop_timer(sk, &hctx->no_feedback_timer); /* * As we have calculated new ipi, delta, t_nom it is possible @@ -488,95 +453,66 @@ done_computing_x: * This can help avoid triggering the nofeedback timer too * often ('spinning') on LANs with small RTTs. */ - hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt, - (CONFIG_IP_DCCP_CCID3_RTO * - (USEC_PER_SEC / 1000))); + hctx->t_rto = max_t(u32, 4 * hctx->rtt, (CONFIG_IP_DCCP_CCID3_RTO * + (USEC_PER_SEC / 1000))); /* * Schedule no feedback timer to expire in * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi) */ - t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi); + t_nfb = max(hctx->t_rto, 2 * hctx->t_ipi); ccid3_pr_debug("%s(%p), Scheduled no feedback timer to " "expire in %lu jiffies (%luus)\n", - dccp_role(sk), - sk, usecs_to_jiffies(t_nfb), t_nfb); + dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb); - sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer, + sk_reset_timer(sk, &hctx->no_feedback_timer, jiffies + usecs_to_jiffies(t_nfb)); } -static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option, - unsigned char len, u16 idx, - unsigned char *value) +static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type, + u8 option, u8 *optval, u8 optlen) { - int rc = 0; - const struct dccp_sock *dp = dccp_sk(sk); struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); - struct ccid3_options_received *opt_recv; __be32 opt_val; - opt_recv = &hctx->ccid3hctx_options_received; - - if (opt_recv->ccid3or_seqno != dp->dccps_gsr) { - opt_recv->ccid3or_seqno = dp->dccps_gsr; - opt_recv->ccid3or_loss_event_rate = ~0; - opt_recv->ccid3or_loss_intervals_idx = 0; - opt_recv->ccid3or_loss_intervals_len = 0; - opt_recv->ccid3or_receive_rate = 0; - } - switch (option) { + case TFRC_OPT_RECEIVE_RATE: case TFRC_OPT_LOSS_EVENT_RATE: - if (unlikely(len != 4)) { - DCCP_WARN("%s(%p), invalid len %d " - "for TFRC_OPT_LOSS_EVENT_RATE\n", - dccp_role(sk), sk, len); - rc = -EINVAL; - } else { - opt_val = get_unaligned((__be32 *)value); - opt_recv->ccid3or_loss_event_rate = ntohl(opt_val); - ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n", - dccp_role(sk), sk, - opt_recv->ccid3or_loss_event_rate); + /* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */ + if (packet_type == DCCP_PKT_DATA) + break; + if (unlikely(optlen != 4)) { + DCCP_WARN("%s(%p), invalid len %d for %u\n", + dccp_role(sk), sk, optlen, option); + return -EINVAL; } - break; - case TFRC_OPT_LOSS_INTERVALS: - opt_recv->ccid3or_loss_intervals_idx = idx; - opt_recv->ccid3or_loss_intervals_len = len; - ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n", - dccp_role(sk), sk, - opt_recv->ccid3or_loss_intervals_idx, - opt_recv->ccid3or_loss_intervals_len); - break; - case TFRC_OPT_RECEIVE_RATE: - if (unlikely(len != 4)) { - DCCP_WARN("%s(%p), invalid len %d " - "for TFRC_OPT_RECEIVE_RATE\n", - dccp_role(sk), sk, len); - rc = -EINVAL; - } else { - opt_val = get_unaligned((__be32 *)value); - opt_recv->ccid3or_receive_rate = ntohl(opt_val); + opt_val = ntohl(get_unaligned((__be32 *)optval)); + + if (option == TFRC_OPT_RECEIVE_RATE) { + /* Receive Rate is kept in units of 64 bytes/second */ + hctx->x_recv = opt_val; + hctx->x_recv <<= 6; + ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n", - dccp_role(sk), sk, - opt_recv->ccid3or_receive_rate); + dccp_role(sk), sk, opt_val); + } else { + /* Update the fixpoint Loss Event Rate fraction */ + hctx->p = tfrc_invert_loss_event_rate(opt_val); + + ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n", + dccp_role(sk), sk, opt_val); } - break; } - - return rc; + return 0; } static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk) { struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid); - hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT; - hctx->ccid3hctx_hist = NULL; - setup_timer(&hctx->ccid3hctx_no_feedback_timer, - ccid3_hc_tx_no_feedback_timer, (unsigned long)sk); - + hctx->hist = NULL; + setup_timer(&hctx->no_feedback_timer, + ccid3_hc_tx_no_feedback_timer, (unsigned long)sk); return 0; } @@ -584,42 +520,36 @@ static void ccid3_hc_tx_exit(struct sock *sk) { struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); - ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM); - sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer); - - tfrc_tx_hist_purge(&hctx->ccid3hctx_hist); + sk_stop_timer(sk, &hctx->no_feedback_timer); + tfrc_tx_hist_purge(&hctx->hist); } static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info) { - struct ccid3_hc_tx_sock *hctx; - - /* Listen socks doesn't have a private CCID block */ - if (sk->sk_state == DCCP_LISTEN) - return; - - hctx = ccid3_hc_tx_sk(sk); - info->tcpi_rto = hctx->ccid3hctx_t_rto; - info->tcpi_rtt = hctx->ccid3hctx_rtt; + info->tcpi_rto = ccid3_hc_tx_sk(sk)->t_rto; + info->tcpi_rtt = ccid3_hc_tx_sk(sk)->rtt; } static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len, u32 __user *optval, int __user *optlen) { - const struct ccid3_hc_tx_sock *hctx; + const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); + struct tfrc_tx_info tfrc; const void *val; - /* Listen socks doesn't have a private CCID block */ - if (sk->sk_state == DCCP_LISTEN) - return -EINVAL; - - hctx = ccid3_hc_tx_sk(sk); switch (optname) { case DCCP_SOCKOPT_CCID_TX_INFO: - if (len < sizeof(hctx->ccid3hctx_tfrc)) + if (len < sizeof(tfrc)) return -EINVAL; - len = sizeof(hctx->ccid3hctx_tfrc); - val = &hctx->ccid3hctx_tfrc; + tfrc.tfrctx_x = hctx->x; + tfrc.tfrctx_x_recv = hctx->x_recv; + tfrc.tfrctx_x_calc = hctx->x_calc; + tfrc.tfrctx_rtt = hctx->rtt; + tfrc.tfrctx_p = hctx->p; + tfrc.tfrctx_rto = hctx->t_rto; + tfrc.tfrctx_ipi = hctx->t_ipi; + len = sizeof(tfrc); + val = &tfrc; break; default: return -ENOPROTOOPT; @@ -634,112 +564,82 @@ static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len, /* * Receiver Half-Connection Routines */ - -/* CCID3 feedback types */ -enum ccid3_fback_type { - CCID3_FBACK_NONE = 0, - CCID3_FBACK_INITIAL, - CCID3_FBACK_PERIODIC, - CCID3_FBACK_PARAM_CHANGE -}; - -#ifdef CONFIG_IP_DCCP_CCID3_DEBUG -static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state) -{ - static char *ccid3_rx_state_names[] = { - [TFRC_RSTATE_NO_DATA] = "NO_DATA", - [TFRC_RSTATE_DATA] = "DATA", - [TFRC_RSTATE_TERM] = "TERM", - }; - - return ccid3_rx_state_names[state]; -} -#endif - -static void ccid3_hc_rx_set_state(struct sock *sk, - enum ccid3_hc_rx_states state) -{ - struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); - enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state; - - ccid3_pr_debug("%s(%p) %-8.8s -> %s\n", - dccp_role(sk), sk, ccid3_rx_state_name(oldstate), - ccid3_rx_state_name(state)); - WARN_ON(state == oldstate); - hcrx->ccid3hcrx_state = state; -} - static void ccid3_hc_rx_send_feedback(struct sock *sk, const struct sk_buff *skb, enum ccid3_fback_type fbtype) { struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); - struct dccp_sock *dp = dccp_sk(sk); - ktime_t now; - s64 delta = 0; - - if (unlikely(hcrx->ccid3hcrx_state == TFRC_RSTATE_TERM)) - return; - - now = ktime_get_real(); switch (fbtype) { case CCID3_FBACK_INITIAL: - hcrx->ccid3hcrx_x_recv = 0; - hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */ + hcrx->x_recv = 0; + hcrx->p_inverse = ~0U; /* see RFC 4342, 8.5 */ break; case CCID3_FBACK_PARAM_CHANGE: + if (unlikely(hcrx->feedback == CCID3_FBACK_NONE)) { + /* + * rfc3448bis-06, 6.3.1: First packet(s) lost or marked + * FIXME: in rfc3448bis the receiver returns X_recv=0 + * here as it normally would in the first feedback packet. + * However this is not possible yet, since the code still + * uses RFC 3448, i.e. + * If (p > 0) + * Calculate X_calc using the TCP throughput equation. + * X = max(min(X_calc, 2*X_recv), s/t_mbi); + * would bring X down to s/t_mbi. That is why we return + * X_recv according to rfc3448bis-06 for the moment. + */ + u32 s = tfrc_rx_hist_packet_size(&hcrx->hist), + rtt = tfrc_rx_hist_rtt(&hcrx->hist); + + hcrx->x_recv = scaled_div32(s, 2 * rtt); + break; + } /* * When parameters change (new loss or p > p_prev), we do not * have a reliable estimate for R_m of [RFC 3448, 6.2] and so - * need to reuse the previous value of X_recv. However, when - * X_recv was 0 (due to early loss), this would kill X down to - * s/t_mbi (i.e. one packet in 64 seconds). - * To avoid such drastic reduction, we approximate X_recv as - * the number of bytes since last feedback. - * This is a safe fallback, since X is bounded above by X_calc. + * always check whether at least RTT time units were covered. */ - if (hcrx->ccid3hcrx_x_recv > 0) - break; - /* fall through */ + hcrx->x_recv = tfrc_rx_hist_x_recv(&hcrx->hist, hcrx->x_recv); + break; case CCID3_FBACK_PERIODIC: - delta = ktime_us_delta(now, hcrx->ccid3hcrx_tstamp_last_feedback); - if (delta <= 0) - DCCP_BUG("delta (%ld) <= 0", (long)delta); - else - hcrx->ccid3hcrx_x_recv = - scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta); + /* + * Step (2) of rfc3448bis-06, 6.2: + * - if no data packets have been received, just restart timer + * - if data packets have been received, re-compute X_recv + */ + if (hcrx->hist.bytes_recvd == 0) + goto prepare_for_next_time; + hcrx->x_recv = tfrc_rx_hist_x_recv(&hcrx->hist, hcrx->x_recv); break; default: return; } - ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", (long)delta, - hcrx->ccid3hcrx_x_recv, hcrx->ccid3hcrx_pinv); - - hcrx->ccid3hcrx_tstamp_last_feedback = now; - hcrx->ccid3hcrx_last_counter = dccp_hdr(skb)->dccph_ccval; - hcrx->ccid3hcrx_bytes_recv = 0; + ccid3_pr_debug("X_recv=%u, 1/p=%u\n", hcrx->x_recv, hcrx->p_inverse); - dp->dccps_hc_rx_insert_options = 1; + dccp_sk(sk)->dccps_hc_rx_insert_options = 1; dccp_send_ack(sk); + +prepare_for_next_time: + tfrc_rx_hist_restart_byte_counter(&hcrx->hist); + hcrx->last_counter = dccp_hdr(skb)->dccph_ccval; + hcrx->feedback = fbtype; } static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb) { - const struct ccid3_hc_rx_sock *hcrx; + const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); __be32 x_recv, pinv; if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)) return 0; - hcrx = ccid3_hc_rx_sk(sk); - if (dccp_packet_without_ack(skb)) return 0; - x_recv = htonl(hcrx->ccid3hcrx_x_recv); - pinv = htonl(hcrx->ccid3hcrx_pinv); + x_recv = htonl(hcrx->x_recv); + pinv = htonl(hcrx->p_inverse); if (dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE, &pinv, sizeof(pinv)) || @@ -762,171 +662,95 @@ static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb) static u32 ccid3_first_li(struct sock *sk) { struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); - u32 x_recv, p, delta; + u32 s = tfrc_rx_hist_packet_size(&hcrx->hist), + rtt = tfrc_rx_hist_rtt(&hcrx->hist), x_recv, p; u64 fval; - if (hcrx->ccid3hcrx_rtt == 0) { - DCCP_WARN("No RTT estimate available, using fallback RTT\n"); - hcrx->ccid3hcrx_rtt = DCCP_FALLBACK_RTT; - } + /* + * rfc3448bis-06, 6.3.1: First data packet(s) are marked or lost. Set p + * to give the equivalent of X_target = s/(2*R). Thus fval = 2 and so p + * is about 20.64%. This yields an interval length of 4.84 (rounded up). + */ + if (unlikely(hcrx->feedback == CCID3_FBACK_NONE)) + return 5; - delta = ktime_to_us(net_timedelta(hcrx->ccid3hcrx_tstamp_last_feedback)); - x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta); - if (x_recv == 0) { /* would also trigger divide-by-zero */ - DCCP_WARN("X_recv==0\n"); - if ((x_recv = hcrx->ccid3hcrx_x_recv) == 0) { - DCCP_BUG("stored value of X_recv is zero"); - return ~0U; - } - } + x_recv = tfrc_rx_hist_x_recv(&hcrx->hist, hcrx->x_recv); + if (x_recv == 0) + goto failed; - fval = scaled_div(hcrx->ccid3hcrx_s, hcrx->ccid3hcrx_rtt); - fval = scaled_div32(fval, x_recv); + fval = scaled_div32(scaled_div(s, rtt), x_recv); p = tfrc_calc_x_reverse_lookup(fval); ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied " "loss rate=%u\n", dccp_role(sk), sk, x_recv, p); - return p == 0 ? ~0U : scaled_div(1, p); + if (p > 0) + return scaled_div(1, p); +failed: + return UINT_MAX; } static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) { struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); - enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE; const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp; const bool is_data_packet = dccp_data_packet(skb); - if (unlikely(hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)) { - if (is_data_packet) { - const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; - do_feedback = CCID3_FBACK_INITIAL; - ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA); - hcrx->ccid3hcrx_s = payload; - /* - * Not necessary to update ccid3hcrx_bytes_recv here, - * since X_recv = 0 for the first feedback packet (cf. - * RFC 3448, 6.3) -- gerrit - */ - } - goto update_records; - } - - if (tfrc_rx_hist_duplicate(&hcrx->ccid3hcrx_hist, skb)) - return; /* done receiving */ - - if (is_data_packet) { - const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; - /* - * Update moving-average of s and the sum of received payload bytes - */ - hcrx->ccid3hcrx_s = tfrc_ewma(hcrx->ccid3hcrx_s, payload, 9); - hcrx->ccid3hcrx_bytes_recv += payload; - } - /* * Perform loss detection and handle pending losses */ - if (tfrc_rx_handle_loss(&hcrx->ccid3hcrx_hist, &hcrx->ccid3hcrx_li_hist, - skb, ndp, ccid3_first_li, sk)) { - do_feedback = CCID3_FBACK_PARAM_CHANGE; - goto done_receiving; - } - - if (tfrc_rx_hist_loss_pending(&hcrx->ccid3hcrx_hist)) - return; /* done receiving */ - + if (tfrc_rx_congestion_event(&hcrx->hist, &hcrx->li_hist, + skb, ndp, ccid3_first_li, sk)) + ccid3_hc_rx_send_feedback(sk, skb, CCID3_FBACK_PARAM_CHANGE); /* - * Handle data packets: RTT sampling and monitoring p + * Feedback for first non-empty data packet (RFC 3448, 6.3) */ - if (unlikely(!is_data_packet)) - goto update_records; - - if (!tfrc_lh_is_initialised(&hcrx->ccid3hcrx_li_hist)) { - const u32 sample = tfrc_rx_hist_sample_rtt(&hcrx->ccid3hcrx_hist, skb); - /* - * Empty loss history: no loss so far, hence p stays 0. - * Sample RTT values, since an RTT estimate is required for the - * computation of p when the first loss occurs; RFC 3448, 6.3.1. - */ - if (sample != 0) - hcrx->ccid3hcrx_rtt = tfrc_ewma(hcrx->ccid3hcrx_rtt, sample, 9); - - } else if (tfrc_lh_update_i_mean(&hcrx->ccid3hcrx_li_hist, skb)) { - /* - * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean - * has decreased (resp. p has increased), send feedback now. - */ - do_feedback = CCID3_FBACK_PARAM_CHANGE; - } - + else if (unlikely(hcrx->feedback == CCID3_FBACK_NONE && is_data_packet)) + ccid3_hc_rx_send_feedback(sk, skb, CCID3_FBACK_INITIAL); /* * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3 */ - if (SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->ccid3hcrx_last_counter) > 3) - do_feedback = CCID3_FBACK_PERIODIC; - -update_records: - tfrc_rx_hist_add_packet(&hcrx->ccid3hcrx_hist, skb, ndp); - -done_receiving: - if (do_feedback) - ccid3_hc_rx_send_feedback(sk, skb, do_feedback); + else if (!tfrc_rx_hist_loss_pending(&hcrx->hist) && is_data_packet && + SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->last_counter) > 3) + ccid3_hc_rx_send_feedback(sk, skb, CCID3_FBACK_PERIODIC); } static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk) { struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid); - hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA; - tfrc_lh_init(&hcrx->ccid3hcrx_li_hist); - return tfrc_rx_hist_alloc(&hcrx->ccid3hcrx_hist); + tfrc_lh_init(&hcrx->li_hist); + return tfrc_rx_hist_init(&hcrx->hist, sk); } static void ccid3_hc_rx_exit(struct sock *sk) { struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); - ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM); - - tfrc_rx_hist_purge(&hcrx->ccid3hcrx_hist); - tfrc_lh_cleanup(&hcrx->ccid3hcrx_li_hist); + tfrc_rx_hist_purge(&hcrx->hist); + tfrc_lh_cleanup(&hcrx->li_hist); } static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info) { - const struct ccid3_hc_rx_sock *hcrx; - - /* Listen socks doesn't have a private CCID block */ - if (sk->sk_state == DCCP_LISTEN) - return; - - hcrx = ccid3_hc_rx_sk(sk); - info->tcpi_ca_state = hcrx->ccid3hcrx_state; info->tcpi_options |= TCPI_OPT_TIMESTAMPS; - info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt; + info->tcpi_rcv_rtt = tfrc_rx_hist_rtt(&ccid3_hc_rx_sk(sk)->hist); } static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len, u32 __user *optval, int __user *optlen) { - const struct ccid3_hc_rx_sock *hcrx; + const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); struct tfrc_rx_info rx_info; const void *val; - /* Listen socks doesn't have a private CCID block */ - if (sk->sk_state == DCCP_LISTEN) - return -EINVAL; - - hcrx = ccid3_hc_rx_sk(sk); switch (optname) { case DCCP_SOCKOPT_CCID_RX_INFO: if (len < sizeof(rx_info)) return -EINVAL; - rx_info.tfrcrx_x_recv = hcrx->ccid3hcrx_x_recv; - rx_info.tfrcrx_rtt = hcrx->ccid3hcrx_rtt; - rx_info.tfrcrx_p = hcrx->ccid3hcrx_pinv == 0 ? ~0U : - scaled_div(1, hcrx->ccid3hcrx_pinv); + rx_info.tfrcrx_x_recv = hcrx->x_recv; + rx_info.tfrcrx_rtt = tfrc_rx_hist_rtt(&hcrx->hist); + rx_info.tfrcrx_p = tfrc_invert_loss_event_rate(hcrx->p_inverse); len = sizeof(rx_info); val = &rx_info; break; @@ -962,6 +786,9 @@ static struct ccid_operations ccid3 = { .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt, }; +module_param(do_osc_prev, bool, 0644); +MODULE_PARM_DESC(do_osc_prev, "Use Oscillation Prevention (RFC 3448, 4.5)"); + #ifdef CONFIG_IP_DCCP_CCID3_DEBUG module_param(ccid3_debug, bool, 0644); MODULE_PARM_DESC(ccid3_debug, "Enable debug messages"); @@ -969,6 +796,19 @@ MODULE_PARM_DESC(ccid3_debug, "Enable debug messages"); static __init int ccid3_module_init(void) { + struct timespec tp; + + /* + * Without a fine-grained clock resolution, RTTs/X_recv are not sampled + * correctly and feedback is sent either too early or too late. + */ + hrtimer_get_res(CLOCK_MONOTONIC, &tp); + if (tp.tv_sec || tp.tv_nsec > DCCP_TIME_RESOLUTION * NSEC_PER_USEC) { + printk(KERN_ERR "%s: Timer too coarse (%ld usec), need %u-usec" + " resolution - check your clocksource.\n", __func__, + tp.tv_nsec/NSEC_PER_USEC, DCCP_TIME_RESOLUTION); + return -ESOCKTNOSUPPORT; + } return ccid_register(&ccid3); } module_init(ccid3_module_init); diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h index 49ca32bd7e79..af6e1bf937d9 100644 --- a/net/dccp/ccids/ccid3.h +++ b/net/dccp/ccids/ccid3.h @@ -47,11 +47,22 @@ /* Two seconds as per RFC 3448 4.2 */ #define TFRC_INITIAL_TIMEOUT (2 * USEC_PER_SEC) -/* In usecs - half the scheduling granularity as per RFC3448 4.6 */ -#define TFRC_OPSYS_HALF_TIME_GRAN (USEC_PER_SEC / (2 * HZ)) +/* Maximum backoff interval t_mbi (RFC 3448, 4.3) */ +#define TFRC_T_MBI (64 * USEC_PER_SEC) -/* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */ -#define TFRC_T_MBI 64 +/* + * The t_delta parameter (RFC 3448, 4.6): delays of less than %USEC_PER_MSEC are + * rounded down to 0, since sk_reset_timer() here uses millisecond granularity. + * Hence we can use a constant t_delta = %USEC_PER_MSEC when HZ >= 500. A coarse + * resolution of HZ < 500 means that the error is below one timer tick (t_gran) + * when using the constant t_delta = t_gran / 2 = %USEC_PER_SEC / (2 * HZ). + */ +#if (HZ >= 500) +# define TFRC_T_DELTA USEC_PER_MSEC +#else +# define TFRC_T_DELTA (USEC_PER_SEC / (2 * HZ)) +#warning Coarse CONFIG_HZ resolution -- higher value recommended for TFRC. +#endif enum ccid3_options { TFRC_OPT_LOSS_EVENT_RATE = 192, @@ -59,62 +70,43 @@ enum ccid3_options { TFRC_OPT_RECEIVE_RATE = 194, }; -struct ccid3_options_received { - u64 ccid3or_seqno:48, - ccid3or_loss_intervals_idx:16; - u16 ccid3or_loss_intervals_len; - u32 ccid3or_loss_event_rate; - u32 ccid3or_receive_rate; -}; - -/* TFRC sender states */ -enum ccid3_hc_tx_states { - TFRC_SSTATE_NO_SENT = 1, - TFRC_SSTATE_NO_FBACK, - TFRC_SSTATE_FBACK, - TFRC_SSTATE_TERM, -}; - /** struct ccid3_hc_tx_sock - CCID3 sender half-connection socket * - * @ccid3hctx_x - Current sending rate in 64 * bytes per second - * @ccid3hctx_x_recv - Receive rate in 64 * bytes per second - * @ccid3hctx_x_calc - Calculated rate in bytes per second - * @ccid3hctx_rtt - Estimate of current round trip time in usecs - * @ccid3hctx_p - Current loss event rate (0-1) scaled by 1000000 - * @ccid3hctx_s - Packet size in bytes - * @ccid3hctx_t_rto - Nofeedback Timer setting in usecs - * @ccid3hctx_t_ipi - Interpacket (send) interval (RFC 3448, 4.6) in usecs - * @ccid3hctx_state - Sender state, one of %ccid3_hc_tx_states - * @ccid3hctx_last_win_count - Last window counter sent - * @ccid3hctx_t_last_win_count - Timestamp of earliest packet - * with last_win_count value sent - * @ccid3hctx_no_feedback_timer - Handle to no feedback timer - * @ccid3hctx_t_ld - Time last doubled during slow start - * @ccid3hctx_t_nom - Nominal send time of next packet - * @ccid3hctx_delta - Send timer delta (RFC 3448, 4.6) in usecs - * @ccid3hctx_hist - Packet history - * @ccid3hctx_options_received - Parsed set of retrieved options + * @x - Current sending rate in 64 * bytes per second + * @x_recv - Receive rate in 64 * bytes per second + * @x_calc - Calculated rate in bytes per second + * @rtt - Estimate of current round trip time in usecs + * @r_sqmean - Estimate of long-term RTT (RFC 3448, 4.5) + * @p - Current loss event rate (0-1) scaled by 1000000 + * @s - Packet size in bytes + * @t_rto - Nofeedback Timer setting in usecs + * @t_ipi - Interpacket (send) interval (RFC 3448, 4.6) in usecs + * @feedback - Whether feedback has been received or not + * @last_win_count - Last window counter sent + * @t_last_win_count - Timestamp of earliest packet with + * last_win_count value sent + * @no_feedback_timer - Handle to no feedback timer + * @t_ld - Time last doubled during slow start + * @t_nom - Nominal send time of next packet + * @hist - Packet history */ struct ccid3_hc_tx_sock { - struct tfrc_tx_info ccid3hctx_tfrc; -#define ccid3hctx_x ccid3hctx_tfrc.tfrctx_x -#define ccid3hctx_x_recv ccid3hctx_tfrc.tfrctx_x_recv -#define ccid3hctx_x_calc ccid3hctx_tfrc.tfrctx_x_calc -#define ccid3hctx_rtt ccid3hctx_tfrc.tfrctx_rtt -#define ccid3hctx_p ccid3hctx_tfrc.tfrctx_p -#define ccid3hctx_t_rto ccid3hctx_tfrc.tfrctx_rto -#define ccid3hctx_t_ipi ccid3hctx_tfrc.tfrctx_ipi - u16 ccid3hctx_s; - enum ccid3_hc_tx_states ccid3hctx_state:8; - u8 ccid3hctx_last_win_count; - ktime_t ccid3hctx_t_last_win_count; - struct timer_list ccid3hctx_no_feedback_timer; - ktime_t ccid3hctx_t_ld; - ktime_t ccid3hctx_t_nom; - u32 ccid3hctx_delta; - struct tfrc_tx_hist_entry *ccid3hctx_hist; - struct ccid3_options_received ccid3hctx_options_received; + u64 x; + u64 x_recv; + u32 x_calc; + u32 rtt; + u16 r_sqmean; + u32 p; + u32 t_rto; + u32 t_ipi; + u16 s; + bool feedback:1; + u8 last_win_count; + ktime_t t_last_win_count; + struct timer_list no_feedback_timer; + ktime_t t_ld; + ktime_t t_nom; + struct tfrc_tx_hist_entry *hist; }; static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk) @@ -124,41 +116,32 @@ static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk) return hctx; } -/* TFRC receiver states */ -enum ccid3_hc_rx_states { - TFRC_RSTATE_NO_DATA = 1, - TFRC_RSTATE_DATA, - TFRC_RSTATE_TERM = 127, + +enum ccid3_fback_type { + CCID3_FBACK_NONE = 0, + CCID3_FBACK_INITIAL, + CCID3_FBACK_PERIODIC, + CCID3_FBACK_PARAM_CHANGE }; /** struct ccid3_hc_rx_sock - CCID3 receiver half-connection socket * - * @ccid3hcrx_x_recv - Receiver estimate of send rate (RFC 3448 4.3) - * @ccid3hcrx_rtt - Receiver estimate of rtt (non-standard) - * @ccid3hcrx_p - Current loss event rate (RFC 3448 5.4) - * @ccid3hcrx_last_counter - Tracks window counter (RFC 4342, 8.1) - * @ccid3hcrx_state - Receiver state, one of %ccid3_hc_rx_states - * @ccid3hcrx_bytes_recv - Total sum of DCCP payload bytes - * @ccid3hcrx_x_recv - Receiver estimate of send rate (RFC 3448, sec. 4.3) - * @ccid3hcrx_rtt - Receiver estimate of RTT - * @ccid3hcrx_tstamp_last_feedback - Time at which last feedback was sent - * @ccid3hcrx_tstamp_last_ack - Time at which last feedback was sent - * @ccid3hcrx_hist - Packet history (loss detection + RTT sampling) - * @ccid3hcrx_li_hist - Loss Interval database - * @ccid3hcrx_s - Received packet size in bytes - * @ccid3hcrx_pinv - Inverse of Loss Event Rate (RFC 4342, sec. 8.5) + * @last_counter - Tracks window counter (RFC 4342, 8.1) + * @feedback - The type of the feedback last sent + * @x_recv - Receiver estimate of send rate (RFC 3448, sec. 4.3) + * @tstamp_last_feedback - Time at which last feedback was sent + * @hist - Packet history (loss detection + RTT sampling) + * @li_hist - Loss Interval database + * @p_inverse - Inverse of Loss Event Rate (RFC 4342, sec. 8.5) */ struct ccid3_hc_rx_sock { - u8 ccid3hcrx_last_counter:4; - enum ccid3_hc_rx_states ccid3hcrx_state:8; - u32 ccid3hcrx_bytes_recv; - u32 ccid3hcrx_x_recv; - u32 ccid3hcrx_rtt; - ktime_t ccid3hcrx_tstamp_last_feedback; - struct tfrc_rx_hist ccid3hcrx_hist; - struct tfrc_loss_hist ccid3hcrx_li_hist; - u16 ccid3hcrx_s; -#define ccid3hcrx_pinv ccid3hcrx_li_hist.i_mean + u8 last_counter:4; + enum ccid3_fback_type feedback:4; + u32 x_recv; + ktime_t tstamp_last_feedback; + struct tfrc_rx_hist hist; + struct tfrc_loss_hist li_hist; +#define p_inverse li_hist.i_mean }; static inline struct ccid3_hc_rx_sock *ccid3_hc_rx_sk(const struct sock *sk) diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c index 5b3ce0688c5c..b1ae8f8259e5 100644 --- a/net/dccp/ccids/lib/loss_interval.c +++ b/net/dccp/ccids/lib/loss_interval.c @@ -86,21 +86,26 @@ static void tfrc_lh_calc_i_mean(struct tfrc_loss_hist *lh) /** * tfrc_lh_update_i_mean - Update the `open' loss interval I_0 - * For recomputing p: returns `true' if p > p_prev <=> 1/p < 1/p_prev + * This updates I_mean as the sequence numbers increase. As a consequence, the + * open loss interval I_0 increases, hence p = W_tot/max(I_tot0, I_tot1) + * decreases, and thus there is no need to send renewed feedback. */ -u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb) +void tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb) { struct tfrc_loss_interval *cur = tfrc_lh_peek(lh); - u32 old_i_mean = lh->i_mean; s64 len; if (cur == NULL) /* not initialised */ - return 0; + return; + + /* FIXME: should probably also count non-data packets (RFC 4342, 6.1) */ + if (!dccp_data_packet(skb)) + return; len = dccp_delta_seqno(cur->li_seqno, DCCP_SKB_CB(skb)->dccpd_seq) + 1; if (len - (s64)cur->li_length <= 0) /* duplicate or reordered */ - return 0; + return; if (SUB16(dccp_hdr(skb)->dccph_ccval, cur->li_ccval) > 4) /* @@ -114,14 +119,11 @@ u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb) cur->li_is_closed = 1; if (tfrc_lh_length(lh) == 1) /* due to RFC 3448, 6.3.1 */ - return 0; + return; cur->li_length = len; tfrc_lh_calc_i_mean(lh); - - return (lh->i_mean < old_i_mean); } -EXPORT_SYMBOL_GPL(tfrc_lh_update_i_mean); /* Determine if `new_loss' does begin a new loss interval [RFC 4342, 10.2] */ static inline u8 tfrc_lh_is_new_loss(struct tfrc_loss_interval *cur, @@ -138,18 +140,18 @@ static inline u8 tfrc_lh_is_new_loss(struct tfrc_loss_interval *cur, * @sk: Used by @calc_first_li in caller-specific way (subtyping) * Updates I_mean and returns 1 if a new interval has in fact been added to @lh. */ -int tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh, - u32 (*calc_first_li)(struct sock *), struct sock *sk) +bool tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh, + u32 (*calc_first_li)(struct sock *), struct sock *sk) { struct tfrc_loss_interval *cur = tfrc_lh_peek(lh), *new; if (cur != NULL && !tfrc_lh_is_new_loss(cur, tfrc_rx_hist_loss_prev(rh))) - return 0; + return false; new = tfrc_lh_demand_next(lh); if (unlikely(new == NULL)) { DCCP_CRIT("Cannot allocate/add loss record."); - return 0; + return false; } new->li_seqno = tfrc_rx_hist_loss_prev(rh)->tfrchrx_seqno; @@ -167,7 +169,7 @@ int tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh, tfrc_lh_calc_i_mean(lh); } - return 1; + return true; } EXPORT_SYMBOL_GPL(tfrc_lh_interval_add); diff --git a/net/dccp/ccids/lib/loss_interval.h b/net/dccp/ccids/lib/loss_interval.h index 246018a3b269..d08a226db43e 100644 --- a/net/dccp/ccids/lib/loss_interval.h +++ b/net/dccp/ccids/lib/loss_interval.h @@ -67,9 +67,9 @@ static inline u8 tfrc_lh_length(struct tfrc_loss_hist *lh) struct tfrc_rx_hist; -extern int tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *, +extern bool tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *, u32 (*first_li)(struct sock *), struct sock *); -extern u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *); +extern void tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *); extern void tfrc_lh_cleanup(struct tfrc_loss_hist *lh); #endif /* _DCCP_LI_HIST_ */ diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c index 6cc108afdc3b..cce9f03bda3e 100644 --- a/net/dccp/ccids/lib/packet_history.c +++ b/net/dccp/ccids/lib/packet_history.c @@ -40,18 +40,6 @@ #include "packet_history.h" #include "../../dccp.h" -/** - * tfrc_tx_hist_entry - Simple singly-linked TX history list - * @next: next oldest entry (LIFO order) - * @seqno: sequence number of this entry - * @stamp: send time of packet with sequence number @seqno - */ -struct tfrc_tx_hist_entry { - struct tfrc_tx_hist_entry *next; - u64 seqno; - ktime_t stamp; -}; - /* * Transmitter History Routines */ @@ -73,15 +61,6 @@ void tfrc_tx_packet_history_exit(void) } } -static struct tfrc_tx_hist_entry * - tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno) -{ - while (head != NULL && head->seqno != seqno) - head = head->next; - - return head; -} - int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno) { struct tfrc_tx_hist_entry *entry = kmem_cache_alloc(tfrc_tx_hist_slab, gfp_any()); @@ -111,25 +90,6 @@ void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp) } EXPORT_SYMBOL_GPL(tfrc_tx_hist_purge); -u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head, const u64 seqno, - const ktime_t now) -{ - u32 rtt = 0; - struct tfrc_tx_hist_entry *packet = tfrc_tx_hist_find_entry(head, seqno); - - if (packet != NULL) { - rtt = ktime_us_delta(now, packet->stamp); - /* - * Garbage-collect older (irrelevant) entries: - */ - tfrc_tx_hist_purge(&packet->next); - } - - return rtt; -} -EXPORT_SYMBOL_GPL(tfrc_tx_hist_rtt); - - /* * Receiver History Routines */ @@ -191,14 +151,31 @@ int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb) } EXPORT_SYMBOL_GPL(tfrc_rx_hist_duplicate); + +static void __tfrc_rx_hist_swap(struct tfrc_rx_hist *h, const u8 a, const u8 b) +{ + struct tfrc_rx_hist_entry *tmp = h->ring[a]; + + h->ring[a] = h->ring[b]; + h->ring[b] = tmp; +} + static void tfrc_rx_hist_swap(struct tfrc_rx_hist *h, const u8 a, const u8 b) { - const u8 idx_a = tfrc_rx_hist_index(h, a), - idx_b = tfrc_rx_hist_index(h, b); - struct tfrc_rx_hist_entry *tmp = h->ring[idx_a]; + __tfrc_rx_hist_swap(h, tfrc_rx_hist_index(h, a), + tfrc_rx_hist_index(h, b)); +} - h->ring[idx_a] = h->ring[idx_b]; - h->ring[idx_b] = tmp; +/** + * tfrc_rx_hist_resume_rtt_sampling - Prepare RX history for RTT sampling + * This is called after loss detection has finished, when the history entry + * with the index of `loss_count' holds the highest-received sequence number. + * RTT sampling requires this information at ring[0] (tfrc_rx_hist_sample_rtt). + */ +static inline void tfrc_rx_hist_resume_rtt_sampling(struct tfrc_rx_hist *h) +{ + __tfrc_rx_hist_swap(h, 0, tfrc_rx_hist_index(h, h->loss_count)); + h->loss_count = h->loss_start = 0; } /* @@ -215,10 +192,8 @@ static void __do_track_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u64 n1) u64 s0 = tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno, s1 = DCCP_SKB_CB(skb)->dccpd_seq; - if (!dccp_loss_free(s0, s1, n1)) { /* gap between S0 and S1 */ + if (!dccp_loss_free(s0, s1, n1)) /* gap between S0 and S1 */ h->loss_count = 1; - tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 1), skb, n1); - } } static void __one_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n2) @@ -240,8 +215,7 @@ static void __one_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n2 if (dccp_loss_free(s2, s1, n1)) { /* hole is filled: S0, S2, and S1 are consecutive */ - h->loss_count = 0; - h->loss_start = tfrc_rx_hist_index(h, 1); + tfrc_rx_hist_resume_rtt_sampling(h); } else /* gap between S2 and S1: just update loss_prev */ tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_loss_prev(h), skb, n2); @@ -294,8 +268,7 @@ static int __two_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n3) if (dccp_loss_free(s1, s2, n2)) { /* entire hole filled by S0, S3, S1, S2 */ - h->loss_start = tfrc_rx_hist_index(h, 2); - h->loss_count = 0; + tfrc_rx_hist_resume_rtt_sampling(h); } else { /* gap remains between S1 and S2 */ h->loss_start = tfrc_rx_hist_index(h, 1); @@ -339,8 +312,7 @@ static void __three_after_loss(struct tfrc_rx_hist *h) if (dccp_loss_free(s2, s3, n3)) { /* no gap between S2 and S3: entire hole is filled */ - h->loss_start = tfrc_rx_hist_index(h, 3); - h->loss_count = 0; + tfrc_rx_hist_resume_rtt_sampling(h); } else { /* gap between S2 and S3 */ h->loss_start = tfrc_rx_hist_index(h, 2); @@ -354,13 +326,13 @@ static void __three_after_loss(struct tfrc_rx_hist *h) } /** - * tfrc_rx_handle_loss - Loss detection and further processing - * @h: The non-empty RX history object - * @lh: Loss Intervals database to update - * @skb: Currently received packet - * @ndp: The NDP count belonging to @skb - * @calc_first_li: Caller-dependent computation of first loss interval in @lh - * @sk: Used by @calc_first_li (see tfrc_lh_interval_add) + * tfrc_rx_congestion_event - Loss detection and further processing + * @h: The non-empty RX history object + * @lh: Loss Intervals database to update + * @skb: Currently received packet + * @ndp: The NDP count belonging to @skb + * @first_li: Caller-dependent computation of first loss interval in @lh + * @sk: Used by @calc_first_li (see tfrc_lh_interval_add) * Chooses action according to pending loss, updates LI database when a new * loss was detected, and does required post-processing. Returns 1 when caller * should send feedback, 0 otherwise. @@ -368,15 +340,20 @@ static void __three_after_loss(struct tfrc_rx_hist *h) * records accordingly, the caller should not perform any more RX history * operations when loss_count is greater than 0 after calling this function. */ -int tfrc_rx_handle_loss(struct tfrc_rx_hist *h, - struct tfrc_loss_hist *lh, - struct sk_buff *skb, const u64 ndp, - u32 (*calc_first_li)(struct sock *), struct sock *sk) +bool tfrc_rx_congestion_event(struct tfrc_rx_hist *h, + struct tfrc_loss_hist *lh, + struct sk_buff *skb, const u64 ndp, + u32 (*first_li)(struct sock *), struct sock *sk) { - int is_new_loss = 0; + bool new_event = false; + + if (tfrc_rx_hist_duplicate(h, skb)) + return 0; if (h->loss_count == 0) { __do_track_loss(h, skb, ndp); + tfrc_rx_hist_sample_rtt(h, skb); + tfrc_rx_hist_add_packet(h, skb, ndp); } else if (h->loss_count == 1) { __one_after_loss(h, skb, ndp); } else if (h->loss_count != 2) { @@ -385,34 +362,57 @@ int tfrc_rx_handle_loss(struct tfrc_rx_hist *h, /* * Update Loss Interval database and recycle RX records */ - is_new_loss = tfrc_lh_interval_add(lh, h, calc_first_li, sk); + new_event = tfrc_lh_interval_add(lh, h, first_li, sk); __three_after_loss(h); } - return is_new_loss; + + /* + * Update moving-average of `s' and the sum of received payload bytes. + */ + if (dccp_data_packet(skb)) { + const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; + + h->packet_size = tfrc_ewma(h->packet_size, payload, 9); + h->bytes_recvd += payload; + } + + /* RFC 3448, 6.1: update I_0, whose growth implies p <= p_prev */ + if (!new_event) + tfrc_lh_update_i_mean(lh, skb); + + return new_event; } -EXPORT_SYMBOL_GPL(tfrc_rx_handle_loss); +EXPORT_SYMBOL_GPL(tfrc_rx_congestion_event); -int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h) +/* Compute the sending rate X_recv measured between feedback intervals */ +u32 tfrc_rx_hist_x_recv(struct tfrc_rx_hist *h, const u32 last_x_recv) { - int i; + u64 bytes = h->bytes_recvd, last_rtt = h->rtt_estimate; + s64 delta = ktime_to_us(net_timedelta(h->bytes_start)); - for (i = 0; i <= TFRC_NDUPACK; i++) { - h->ring[i] = kmem_cache_alloc(tfrc_rx_hist_slab, GFP_ATOMIC); - if (h->ring[i] == NULL) - goto out_free; - } + WARN_ON(delta <= 0); + /* + * Ensure that the sampling interval for X_recv is at least one RTT, + * by extending the sampling interval backwards in time, over the last + * R_(m-1) seconds, as per rfc3448bis-06, 6.2. + * To reduce noise (e.g. when the RTT changes often), this is only + * done when delta is smaller than RTT/2. + */ + if (last_x_recv > 0 && delta < last_rtt/2) { + tfrc_pr_debug("delta < RTT ==> %ld us < %u us\n", + (long)delta, (unsigned)last_rtt); - h->loss_count = h->loss_start = 0; - return 0; + delta = (bytes ? delta : 0) + last_rtt; + bytes += div_u64((u64)last_x_recv * last_rtt, USEC_PER_SEC); + } -out_free: - while (i-- != 0) { - kmem_cache_free(tfrc_rx_hist_slab, h->ring[i]); - h->ring[i] = NULL; + if (unlikely(bytes == 0)) { + DCCP_WARN("X_recv == 0, using old value of %u\n", last_x_recv); + return last_x_recv; } - return -ENOBUFS; + return scaled_div32(bytes, delta); } -EXPORT_SYMBOL_GPL(tfrc_rx_hist_alloc); +EXPORT_SYMBOL_GPL(tfrc_rx_hist_x_recv); void tfrc_rx_hist_purge(struct tfrc_rx_hist *h) { @@ -426,73 +426,81 @@ void tfrc_rx_hist_purge(struct tfrc_rx_hist *h) } EXPORT_SYMBOL_GPL(tfrc_rx_hist_purge); -/** - * tfrc_rx_hist_rtt_last_s - reference entry to compute RTT samples against - */ -static inline struct tfrc_rx_hist_entry * - tfrc_rx_hist_rtt_last_s(const struct tfrc_rx_hist *h) +static int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h) { - return h->ring[0]; + int i; + + memset(h, 0, sizeof(*h)); + + for (i = 0; i <= TFRC_NDUPACK; i++) { + h->ring[i] = kmem_cache_alloc(tfrc_rx_hist_slab, GFP_ATOMIC); + if (h->ring[i] == NULL) { + tfrc_rx_hist_purge(h); + return -ENOBUFS; + } + } + return 0; } -/** - * tfrc_rx_hist_rtt_prev_s: previously suitable (wrt rtt_last_s) RTT-sampling entry - */ -static inline struct tfrc_rx_hist_entry * - tfrc_rx_hist_rtt_prev_s(const struct tfrc_rx_hist *h) +int tfrc_rx_hist_init(struct tfrc_rx_hist *h, struct sock *sk) { - return h->ring[h->rtt_sample_prev]; + if (tfrc_rx_hist_alloc(h)) + return -ENOBUFS; + /* + * Initialise first entry with GSR to start loss detection as early as + * possible. Code using this must not use any other fields. The entry + * will be overwritten once the CCID updates its received packets. + */ + tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno = dccp_sk(sk)->dccps_gsr; + return 0; } +EXPORT_SYMBOL_GPL(tfrc_rx_hist_init); /** * tfrc_rx_hist_sample_rtt - Sample RTT from timestamp / CCVal - * Based on ideas presented in RFC 4342, 8.1. Returns 0 if it was not able - * to compute a sample with given data - calling function should check this. + * Based on ideas presented in RFC 4342, 8.1. This function expects that no loss + * is pending and uses the following history entries (via rtt_sample_prev): + * - h->ring[0] contains the most recent history entry prior to @skb; + * - h->ring[1] is an unused `dummy' entry when the current difference is 0; */ -u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, const struct sk_buff *skb) +void tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, const struct sk_buff *skb) { - u32 sample = 0, - delta_v = SUB16(dccp_hdr(skb)->dccph_ccval, - tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval); - - if (delta_v < 1 || delta_v > 4) { /* unsuitable CCVal delta */ - if (h->rtt_sample_prev == 2) { /* previous candidate stored */ - sample = SUB16(tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_ccval, - tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval); - if (sample) - sample = 4 / sample * - ktime_us_delta(tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_tstamp, - tfrc_rx_hist_rtt_last_s(h)->tfrchrx_tstamp); - else /* - * FIXME: This condition is in principle not - * possible but occurs when CCID is used for - * two-way data traffic. I have tried to trace - * it, but the cause does not seem to be here. - */ - DCCP_BUG("please report to dccp@vger.kernel.org" - " => prev = %u, last = %u", - tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_ccval, - tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval); - } else if (delta_v < 1) { - h->rtt_sample_prev = 1; - goto keep_ref_for_next_time; - } + struct tfrc_rx_hist_entry *last = h->ring[0]; + u32 sample, delta_v; - } else if (delta_v == 4) /* optimal match */ - sample = ktime_to_us(net_timedelta(tfrc_rx_hist_rtt_last_s(h)->tfrchrx_tstamp)); - else { /* suboptimal match */ - h->rtt_sample_prev = 2; - goto keep_ref_for_next_time; - } + /* + * When not to sample: + * - on non-data packets + * (RFC 4342, 8.1: CCVal only fully defined for data packets); + * - when no data packets have been received yet + * (FIXME: using sampled packet size as indicator here); + * - as long as there are gaps in the sequence space (pending loss). + */ + if (!dccp_data_packet(skb) || h->packet_size == 0 || + tfrc_rx_hist_loss_pending(h)) + return; - if (unlikely(sample > DCCP_SANE_RTT_MAX)) { - DCCP_WARN("RTT sample %u too large, using max\n", sample); - sample = DCCP_SANE_RTT_MAX; + h->rtt_sample_prev = 0; /* reset previous candidate */ + + delta_v = SUB16(dccp_hdr(skb)->dccph_ccval, last->tfrchrx_ccval); + if (delta_v == 0) { /* less than RTT/4 difference */ + h->rtt_sample_prev = 1; + return; } + sample = dccp_sane_rtt(ktime_to_us(net_timedelta(last->tfrchrx_tstamp))); - h->rtt_sample_prev = 0; /* use current entry as next reference */ -keep_ref_for_next_time: + if (delta_v <= 4) /* between RTT/4 and RTT */ + sample *= 4 / delta_v; + else if (!(sample < h->rtt_estimate && sample > h->rtt_estimate/2)) + /* + * Optimisation: CCVal difference is greater than 1 RTT, yet the + * sample is less than the local RTT estimate; which means that + * the RTT estimate is too high. + * To avoid noise, it is not done if the sample is below RTT/2. + */ + return; - return sample; + /* Use a lower weight than usual to increase responsiveness */ + h->rtt_estimate = tfrc_ewma(h->rtt_estimate, sample, 5); } EXPORT_SYMBOL_GPL(tfrc_rx_hist_sample_rtt); diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h index 461cc91cce88..555e65cd73a0 100644 --- a/net/dccp/ccids/lib/packet_history.h +++ b/net/dccp/ccids/lib/packet_history.h @@ -40,12 +40,28 @@ #include <linux/slab.h> #include "tfrc.h" -struct tfrc_tx_hist_entry; +/** + * tfrc_tx_hist_entry - Simple singly-linked TX history list + * @next: next oldest entry (LIFO order) + * @seqno: sequence number of this entry + * @stamp: send time of packet with sequence number @seqno + */ +struct tfrc_tx_hist_entry { + struct tfrc_tx_hist_entry *next; + u64 seqno; + ktime_t stamp; +}; + +static inline struct tfrc_tx_hist_entry * + tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno) +{ + while (head != NULL && head->seqno != seqno) + head = head->next; + return head; +} extern int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno); extern void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp); -extern u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head, - const u64 seqno, const ktime_t now); /* Subtraction a-b modulo-16, respects circular wrap-around */ #define SUB16(a, b) (((a) + 16 - (b)) & 0xF) @@ -75,12 +91,22 @@ struct tfrc_rx_hist_entry { * @loss_count: Number of entries in circular history * @loss_start: Movable index (for loss detection) * @rtt_sample_prev: Used during RTT sampling, points to candidate entry + * @rtt_estimate: Receiver RTT estimate + * @packet_size: Packet size in bytes (as per RFC 3448, 3.1) + * @bytes_recvd: Number of bytes received since @bytes_start + * @bytes_start: Start time for counting @bytes_recvd */ struct tfrc_rx_hist { struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1]; u8 loss_count:2, loss_start:2; + /* Receiver RTT sampling */ #define rtt_sample_prev loss_start + u32 rtt_estimate; + /* Receiver sampling of application payload lengths */ + u32 packet_size, + bytes_recvd; + ktime_t bytes_start; }; /** @@ -124,20 +150,50 @@ static inline bool tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h) return h->loss_count > 0; } +/* + * Accessor functions to retrieve parameters sampled by the RX history + */ +static inline u32 tfrc_rx_hist_packet_size(const struct tfrc_rx_hist *h) +{ + if (h->packet_size == 0) { + DCCP_WARN("No sample for s, using fallback\n"); + return TCP_MIN_RCVMSS; + } + return h->packet_size; + +} +static inline u32 tfrc_rx_hist_rtt(const struct tfrc_rx_hist *h) +{ + if (h->rtt_estimate == 0) { + DCCP_WARN("No RTT estimate available, using fallback RTT\n"); + return DCCP_FALLBACK_RTT; + } + return h->rtt_estimate; +} + +static inline void tfrc_rx_hist_restart_byte_counter(struct tfrc_rx_hist *h) +{ + h->bytes_recvd = 0; + h->bytes_start = ktime_get_real(); +} + +extern u32 tfrc_rx_hist_x_recv(struct tfrc_rx_hist *h, const u32 last_x_recv); + + extern void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h, const struct sk_buff *skb, const u64 ndp); extern int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb); struct tfrc_loss_hist; -extern int tfrc_rx_handle_loss(struct tfrc_rx_hist *h, - struct tfrc_loss_hist *lh, - struct sk_buff *skb, const u64 ndp, - u32 (*first_li)(struct sock *sk), - struct sock *sk); -extern u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, - const struct sk_buff *skb); -extern int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h); +extern bool tfrc_rx_congestion_event(struct tfrc_rx_hist *h, + struct tfrc_loss_hist *lh, + struct sk_buff *skb, const u64 ndp, + u32 (*first_li)(struct sock *sk), + struct sock *sk); +extern void tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, + const struct sk_buff *skb); +extern int tfrc_rx_hist_init(struct tfrc_rx_hist *h, struct sock *sk); extern void tfrc_rx_hist_purge(struct tfrc_rx_hist *h); #endif /* _DCCP_PKT_HIST_ */ diff --git a/net/dccp/ccids/lib/tfrc.h b/net/dccp/ccids/lib/tfrc.h index ed9857527acf..ede12f53de5a 100644 --- a/net/dccp/ccids/lib/tfrc.h +++ b/net/dccp/ccids/lib/tfrc.h @@ -48,6 +48,21 @@ static inline u32 scaled_div32(u64 a, u64 b) } /** + * tfrc_scaled_sqrt - Compute scaled integer sqrt(x) for 0 < x < 2^22-1 + * Uses scaling to improve accuracy of the integer approximation of sqrt(). The + * scaling factor of 2^10 limits the maximum @sample to 4e6; this is okay for + * clamped RTT samples (dccp_sample_rtt). + * Should best be used for expressions of type sqrt(x)/sqrt(y), since then the + * scaling factor is neutralised. For this purpose, it avoids returning zero. + */ +static inline u16 tfrc_scaled_sqrt(const u32 sample) +{ + const unsigned long non_zero_sample = sample ? : 1; + + return int_sqrt(non_zero_sample << 10); +} + +/** * tfrc_ewma - Exponentially weighted moving average * @weight: Weight to be used as damping factor, in units of 1/10 */ @@ -58,6 +73,7 @@ static inline u32 tfrc_ewma(const u32 avg, const u32 newval, const u8 weight) extern u32 tfrc_calc_x(u16 s, u32 R, u32 p); extern u32 tfrc_calc_x_reverse_lookup(u32 fvalue); +extern u32 tfrc_invert_loss_event_rate(u32 loss_event_rate); extern int tfrc_tx_packet_history_init(void); extern void tfrc_tx_packet_history_exit(void); diff --git a/net/dccp/ccids/lib/tfrc_equation.c b/net/dccp/ccids/lib/tfrc_equation.c index 2f20a29cffe4..38239c4d5e14 100644 --- a/net/dccp/ccids/lib/tfrc_equation.c +++ b/net/dccp/ccids/lib/tfrc_equation.c @@ -632,8 +632,16 @@ u32 tfrc_calc_x(u16 s, u32 R, u32 p) if (p <= TFRC_CALC_X_SPLIT) { /* 0.0000 < p <= 0.05 */ if (p < TFRC_SMALLEST_P) { /* 0.0000 < p < 0.0001 */ - DCCP_WARN("Value of p (%d) below resolution. " - "Substituting %d\n", p, TFRC_SMALLEST_P); + /* + * In the congestion-avoidance phase p decays towards 0 + * when there are no further losses, so this case is + * natural. Truncating to p_min = 0.01% means that the + * maximum achievable throughput is limited to about + * X_calc_max = 122.4 * s/RTT (see RFC 3448, 3.1); e.g. + * with s=1500 bytes, RTT=0.01 s: X_calc_max = 147 Mbps. + */ + tfrc_pr_debug("Value of p (%d) below resolution. " + "Substituting %d\n", p, TFRC_SMALLEST_P); index = 0; } else /* 0.0001 <= p <= 0.05 */ index = p/TFRC_SMALLEST_P - 1; @@ -658,7 +666,6 @@ u32 tfrc_calc_x(u16 s, u32 R, u32 p) result = scaled_div(s, R); return scaled_div32(result, f); } - EXPORT_SYMBOL_GPL(tfrc_calc_x); /** @@ -693,5 +700,19 @@ u32 tfrc_calc_x_reverse_lookup(u32 fvalue) index = tfrc_binsearch(fvalue, 0); return (index + 1) * 1000000 / TFRC_CALC_X_ARRSIZE; } - EXPORT_SYMBOL_GPL(tfrc_calc_x_reverse_lookup); + +/** + * tfrc_invert_loss_event_rate - Compute p so that 10^6 corresponds to 100% + * When @loss_event_rate is large, there is a chance that p is truncated to 0. + * To avoid re-entering slow-start in that case, we set p = TFRC_SMALLEST_P > 0. + */ +u32 tfrc_invert_loss_event_rate(u32 loss_event_rate) +{ + if (loss_event_rate == UINT_MAX) /* see RFC 4342, 8.5 */ + return 0; + if (unlikely(loss_event_rate == 0)) /* map 1/0 into 100% */ + return 1000000; + return max_t(u32, scaled_div(1, loss_event_rate), TFRC_SMALLEST_P); +} +EXPORT_SYMBOL_GPL(tfrc_invert_loss_event_rate); diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h index b4bc6e095a0e..5281190aa19c 100644 --- a/net/dccp/dccp.h +++ b/net/dccp/dccp.h @@ -42,9 +42,11 @@ extern int dccp_debug; #define dccp_pr_debug(format, a...) DCCP_PR_DEBUG(dccp_debug, format, ##a) #define dccp_pr_debug_cat(format, a...) DCCP_PRINTK(dccp_debug, format, ##a) +#define dccp_debug(fmt, a...) dccp_pr_debug_cat(KERN_DEBUG fmt, ##a) #else #define dccp_pr_debug(format, a...) #define dccp_pr_debug_cat(format, a...) +#define dccp_debug(format, a...) #endif extern struct inet_hashinfo dccp_hashinfo; @@ -61,11 +63,14 @@ extern void dccp_time_wait(struct sock *sk, int state, int timeo); * - DCCP-Reset with ACK Subheader and 4 bytes of Reset Code fields * Hence a safe upper bound for the maximum option length is 1020-28 = 992 */ -#define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(int)) +#define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(uint32_t)) #define DCCP_MAX_PACKET_HDR 28 #define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR) #define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER) +/* Upper bound for initial feature-negotiation overhead (padded to 32 bits) */ +#define DCCP_FEATNEG_OVERHEAD (32 * sizeof(uint32_t)) + #define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT * state, about 60 seconds */ @@ -81,10 +86,13 @@ extern void dccp_time_wait(struct sock *sk, int state, int timeo); */ #define DCCP_RTO_MAX ((unsigned)(64 * HZ)) +/* DCCP base time resolution - 10 microseconds (RFC 4340, 13.1 ... 13.3) */ +#define DCCP_TIME_RESOLUTION 10 + /* * RTT sampling: sanity bounds and fallback RTT value from RFC 4340, section 3.4 */ -#define DCCP_SANE_RTT_MIN 100 +#define DCCP_SANE_RTT_MIN (10 * DCCP_TIME_RESOLUTION) #define DCCP_FALLBACK_RTT (USEC_PER_SEC / 5) #define DCCP_SANE_RTT_MAX (3 * USEC_PER_SEC) @@ -95,12 +103,6 @@ extern void dccp_time_wait(struct sock *sk, int state, int timeo); extern int sysctl_dccp_request_retries; extern int sysctl_dccp_retries1; extern int sysctl_dccp_retries2; -extern int sysctl_dccp_feat_sequence_window; -extern int sysctl_dccp_feat_rx_ccid; -extern int sysctl_dccp_feat_tx_ccid; -extern int sysctl_dccp_feat_ack_ratio; -extern int sysctl_dccp_feat_send_ack_vector; -extern int sysctl_dccp_feat_send_ndp_count; extern int sysctl_dccp_tx_qlen; extern int sysctl_dccp_sync_ratelimit; @@ -235,8 +237,22 @@ extern void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, extern void dccp_send_sync(struct sock *sk, const u64 seq, const enum dccp_pkt_type pkt_type); -extern void dccp_write_xmit(struct sock *sk, int block); +/* + * TX Packet Dequeueing Interface + */ +extern void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb); +extern bool dccp_qpolicy_full(struct sock *sk); +extern void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb); +extern struct sk_buff *dccp_qpolicy_top(struct sock *sk); +extern struct sk_buff *dccp_qpolicy_pop(struct sock *sk); +extern bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param); + +/* + * TX Packet Output and TX Timers + */ +extern void dccp_write_xmit(struct sock *sk); extern void dccp_write_space(struct sock *sk); +extern void dccp_flush_write_queue(struct sock *sk, long *time_budget); extern void dccp_init_xmit_timers(struct sock *sk); static inline void dccp_clear_xmit_timers(struct sock *sk) @@ -252,7 +268,8 @@ extern const char *dccp_state_name(const int state); extern void dccp_set_state(struct sock *sk, const int state); extern void dccp_done(struct sock *sk); -extern void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb); +extern int dccp_reqsk_init(struct request_sock *rq, struct dccp_sock const *dp, + struct sk_buff const *skb); extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb); @@ -317,7 +334,14 @@ extern struct sk_buff *dccp_ctl_make_reset(struct sock *sk, extern int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code); extern void dccp_send_close(struct sock *sk, const int active); extern int dccp_invalid_packet(struct sk_buff *skb); -extern u32 dccp_sample_rtt(struct sock *sk, long delta); + +static inline u32 dccp_sane_rtt(long usec_sample) +{ + if (unlikely(usec_sample <= 0 || usec_sample > DCCP_SANE_RTT_MAX)) + DCCP_WARN("RTT sample %ld out of bounds!\n", usec_sample); + return clamp_val(usec_sample, DCCP_SANE_RTT_MIN, DCCP_SANE_RTT_MAX); +} +extern u32 dccp_sample_rtt(struct sock *sk, long delta); static inline int dccp_bad_service_code(const struct sock *sk, const __be32 service) @@ -411,36 +435,62 @@ static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack, static inline void dccp_update_gsr(struct sock *sk, u64 seq) { struct dccp_sock *dp = dccp_sk(sk); - const struct dccp_minisock *dmsk = dccp_msk(sk); dp->dccps_gsr = seq; - dccp_set_seqno(&dp->dccps_swl, - dp->dccps_gsr + 1 - (dmsk->dccpms_sequence_window / 4)); - dccp_set_seqno(&dp->dccps_swh, - dp->dccps_gsr + (3 * dmsk->dccpms_sequence_window) / 4); + /* Sequence validity window depends on remote Sequence Window (7.5.1) */ + dp->dccps_swl = SUB48(ADD48(dp->dccps_gsr, 1), dp->dccps_r_seq_win / 4); + /* + * Adjust SWL so that it is not below ISR. In contrast to RFC 4340, + * 7.5.1 we perform this check beyond the initial handshake: W/W' are + * always > 32, so for the first W/W' packets in the lifetime of a + * connection we always have to adjust SWL. + * A second reason why we are doing this is that the window depends on + * the feature-remote value of Sequence Window: nothing stops the peer + * from updating this value while we are busy adjusting SWL for the + * first W packets (we would have to count from scratch again then). + * Therefore it is safer to always make sure that the Sequence Window + * is not artificially extended by a peer who grows SWL downwards by + * continually updating the feature-remote Sequence-Window. + * If sequence numbers wrap it is bad luck. But that will take a while + * (48 bit), and this measure prevents Sequence-number attacks. + */ + if (before48(dp->dccps_swl, dp->dccps_isr)) + dp->dccps_swl = dp->dccps_isr; + dp->dccps_swh = ADD48(dp->dccps_gsr, (3 * dp->dccps_r_seq_win) / 4); } static inline void dccp_update_gss(struct sock *sk, u64 seq) { struct dccp_sock *dp = dccp_sk(sk); - dp->dccps_awh = dp->dccps_gss = seq; - dccp_set_seqno(&dp->dccps_awl, - (dp->dccps_gss - - dccp_msk(sk)->dccpms_sequence_window + 1)); + dp->dccps_gss = seq; + /* Ack validity window depends on local Sequence Window value (7.5.1) */ + dp->dccps_awl = SUB48(ADD48(dp->dccps_gss, 1), dp->dccps_l_seq_win); + /* Adjust AWL so that it is not below ISS - see comment above for SWL */ + if (before48(dp->dccps_awl, dp->dccps_iss)) + dp->dccps_awl = dp->dccps_iss; + dp->dccps_awh = dp->dccps_gss; +} + +static inline int dccp_ackvec_pending(const struct sock *sk) +{ + return dccp_sk(sk)->dccps_hc_rx_ackvec != NULL && + !dccp_ackvec_is_empty(dccp_sk(sk)->dccps_hc_rx_ackvec); } static inline int dccp_ack_pending(const struct sock *sk) { - const struct dccp_sock *dp = dccp_sk(sk); - return dp->dccps_timestamp_echo != 0 || -#ifdef CONFIG_IP_DCCP_ACKVEC - (dccp_msk(sk)->dccpms_send_ack_vector && - dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) || -#endif - inet_csk_ack_scheduled(sk); + return dccp_ackvec_pending(sk) || inet_csk_ack_scheduled(sk); } +extern int dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val); +extern int dccp_feat_finalise_settings(struct dccp_sock *dp); +extern int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq); +extern int dccp_feat_insert_opts(struct dccp_sock*, struct dccp_request_sock*, + struct sk_buff *skb); +extern int dccp_feat_activate_values(struct sock *sk, struct list_head *fn); +extern void dccp_feat_list_purge(struct list_head *fn_list); + extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb); extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*); extern int dccp_insert_option_elapsed_time(struct sock *sk, diff --git a/net/dccp/diag.c b/net/dccp/diag.c index d8a3509b26f6..93aae7c95550 100644 --- a/net/dccp/diag.c +++ b/net/dccp/diag.c @@ -29,7 +29,7 @@ static void dccp_get_info(struct sock *sk, struct tcp_info *info) info->tcpi_backoff = icsk->icsk_backoff; info->tcpi_pmtu = icsk->icsk_pmtu_cookie; - if (dccp_msk(sk)->dccpms_send_ack_vector) + if (dp->dccps_hc_rx_ackvec != NULL) info->tcpi_options |= TCPI_OPT_SACK; ccid_hc_rx_get_info(dp->dccps_hc_rx_ccid, sk, info); diff --git a/net/dccp/feat.c b/net/dccp/feat.c index 933a0ecf8d46..f94c7c9d1a7f 100644 --- a/net/dccp/feat.c +++ b/net/dccp/feat.c @@ -1,11 +1,19 @@ /* * net/dccp/feat.c * - * An implementation of the DCCP protocol - * Andrea Bittau <a.bittau@cs.ucl.ac.uk> + * Feature negotiation for the DCCP protocol (RFC 4340, section 6) + * + * Copyright (c) 2008 The University of Aberdeen, Scotland, UK + * Copyright (c) 2008 Gerrit Renker <gerrit@erg.abdn.ac.uk> + * Rewrote from scratch, some bits from earlier code by + * Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk> + * * * ASSUMPTIONS * ----------- + * o Feature negotiation is coordinated with connection setup (as in TCP), wild + * changes of parameters of an established connection are not supported. + * o Changing NN values (Ack Ratio only) is supported in state OPEN/PARTOPEN. * o All currently known SP features have 1-byte quantities. If in the future * extensions of RFCs 4340..42 define features with item lengths larger than * one byte, a feature-specific extension of the code will be required. @@ -15,635 +23,1510 @@ * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ - #include <linux/module.h> - #include "ccid.h" #include "feat.h" -#define DCCP_FEAT_SP_NOAGREE (-123) - -int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature, - u8 *val, u8 len, gfp_t gfp) -{ - struct dccp_opt_pend *opt; - - dccp_feat_debug(type, feature, *val); - - if (len > 3) { - DCCP_WARN("invalid length %d\n", len); - return -EINVAL; - } - /* XXX add further sanity checks */ - - /* check if that feature is already being negotiated */ - list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { - /* ok we found a negotiation for this option already */ - if (opt->dccpop_feat == feature && opt->dccpop_type == type) { - dccp_pr_debug("Replacing old\n"); - /* replace */ - BUG_ON(opt->dccpop_val == NULL); - kfree(opt->dccpop_val); - opt->dccpop_val = val; - opt->dccpop_len = len; - opt->dccpop_conf = 0; - return 0; - } - } - - /* negotiation for a new feature */ - opt = kmalloc(sizeof(*opt), gfp); - if (opt == NULL) - return -ENOMEM; - - opt->dccpop_type = type; - opt->dccpop_feat = feature; - opt->dccpop_len = len; - opt->dccpop_val = val; - opt->dccpop_conf = 0; - opt->dccpop_sc = NULL; - - BUG_ON(opt->dccpop_val == NULL); - - list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending); - return 0; -} +/* feature-specific sysctls - initialised to the defaults from RFC 4340, 6.4 */ +unsigned long sysctl_dccp_sequence_window __read_mostly = 100; +int sysctl_dccp_rx_ccid __read_mostly = 2, + sysctl_dccp_tx_ccid __read_mostly = 2; -EXPORT_SYMBOL_GPL(dccp_feat_change); - -static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr) +/* + * Feature activation handlers. + * + * These all use an u64 argument, to provide enough room for NN/SP features. At + * this stage the negotiated values have been checked to be within their range. + */ +static int dccp_hdlr_ccid(struct sock *sk, u64 ccid, bool rx) { struct dccp_sock *dp = dccp_sk(sk); - struct dccp_minisock *dmsk = dccp_msk(sk); - /* figure out if we are changing our CCID or the peer's */ - const int rx = type == DCCPO_CHANGE_R; - const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid; - struct ccid *new_ccid; - - /* Check if nothing is being changed. */ - if (ccid_nr == new_ccid_nr) - return 0; + struct ccid *new_ccid = ccid_new(ccid, sk, rx, gfp_any()); - new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC); if (new_ccid == NULL) return -ENOMEM; if (rx) { ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk); dp->dccps_hc_rx_ccid = new_ccid; - dmsk->dccpms_rx_ccid = new_ccid_nr; } else { ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk); dp->dccps_hc_tx_ccid = new_ccid; - dmsk->dccpms_tx_ccid = new_ccid_nr; } - return 0; } -static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val) +static int dccp_hdlr_seq_win(struct sock *sk, u64 seq_win, bool rx) { - dccp_feat_debug(type, feat, val); + struct dccp_sock *dp = dccp_sk(sk); - switch (feat) { - case DCCPF_CCID: - return dccp_feat_update_ccid(sk, type, val); - default: - dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n", - dccp_feat_typename(type), feat); - break; + if (rx) { + dp->dccps_r_seq_win = seq_win; + /* propagate changes to update SWL/SWH */ + dccp_update_gsr(sk, dp->dccps_gsr); + } else { + dp->dccps_l_seq_win = seq_win; + /* propagate changes to update AWL */ + dccp_update_gss(sk, dp->dccps_gss); } return 0; } -static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt, - u8 *rpref, u8 rlen) +static int dccp_hdlr_ack_ratio(struct sock *sk, u64 ratio, bool rx) +{ +#ifndef __CCID2_COPES_GRACEFULLY_WITH_DYNAMIC_ACK_RATIO_UPDATES__ + /* + * FIXME: This is required until several problems in the CCID-2 code are + * resolved. The CCID-2 code currently does not cope well; using dynamic + * Ack Ratios greater than 1 caused instabilities. These were manifest + * in hangups and long RTO timeouts (1...3 seconds). Until this has been + * stabilised, it is safer not to activate dynamic Ack Ratio changes. + */ + dccp_pr_debug("Not changing %s Ack Ratio from 1 to %u\n", + rx ? "RX" : "TX", (u16)ratio); + ratio = 1; +#endif + if (rx) + dccp_sk(sk)->dccps_r_ack_ratio = ratio; + else + dccp_sk(sk)->dccps_l_ack_ratio = ratio; + return 0; +} + +static int dccp_hdlr_ackvec(struct sock *sk, u64 enable, bool rx) { struct dccp_sock *dp = dccp_sk(sk); - u8 *spref, slen, *res = NULL; - int i, j, rc, agree = 1; - BUG_ON(rpref == NULL); + if (rx) { + if (enable && dp->dccps_hc_rx_ackvec == NULL) { + dp->dccps_hc_rx_ackvec = dccp_ackvec_alloc(gfp_any()); + if (dp->dccps_hc_rx_ackvec == NULL) + return -ENOMEM; + } else if (!enable) { + dccp_ackvec_free(dp->dccps_hc_rx_ackvec); + dp->dccps_hc_rx_ackvec = NULL; + } + } + return 0; +} - /* check if we are the black sheep */ - if (dp->dccps_role == DCCP_ROLE_CLIENT) { - spref = rpref; - slen = rlen; - rpref = opt->dccpop_val; - rlen = opt->dccpop_len; - } else { - spref = opt->dccpop_val; - slen = opt->dccpop_len; +static int dccp_hdlr_ndp(struct sock *sk, u64 enable, bool rx) +{ + if (!rx) + dccp_sk(sk)->dccps_send_ndp_count = (enable > 0); + return 0; +} + +/* + * Minimum Checksum Coverage is located at the RX side (9.2.1). This means that + * `rx' holds when the sending peer informs about his partial coverage via a + * ChangeR() option. In the other case, we are the sender and the receiver + * announces its coverage via ChangeL() options. The policy here is to honour + * such communication by enabling the corresponding partial coverage - but only + * if it has not been set manually before; the warning here means that all + * packets will be dropped. + */ +static int dccp_hdlr_min_cscov(struct sock *sk, u64 cscov, bool rx) +{ + struct dccp_sock *dp = dccp_sk(sk); + + if (rx) + dp->dccps_pcrlen = cscov; + else { + if (dp->dccps_pcslen == 0) + dp->dccps_pcslen = cscov; + else if (cscov > dp->dccps_pcslen) + DCCP_WARN("CsCov %u too small, peer requires >= %u\n", + dp->dccps_pcslen, (u8)cscov); } + return 0; +} + +static const struct { + u8 feat_num; /* DCCPF_xxx */ + enum dccp_feat_type rxtx; /* RX or TX */ + enum dccp_feat_type reconciliation; /* SP or NN */ + u8 default_value; /* as in 6.4 */ + int (*activation_hdlr)(struct sock *sk, u64 val, bool rx); +/* + * Lookup table for location and type of features (from RFC 4340/4342) + * +--------------------------+----+-----+----+----+---------+-----------+ + * | Feature | Location | Reconc. | Initial | Section | + * | | RX | TX | SP | NN | Value | Reference | + * +--------------------------+----+-----+----+----+---------+-----------+ + * | DCCPF_CCID | | X | X | | 2 | 10 | + * | DCCPF_SHORT_SEQNOS | | X | X | | 0 | 7.6.1 | + * | DCCPF_SEQUENCE_WINDOW | | X | | X | 100 | 7.5.2 | + * | DCCPF_ECN_INCAPABLE | X | | X | | 0 | 12.1 | + * | DCCPF_ACK_RATIO | | X | | X | 2 | 11.3 | + * | DCCPF_SEND_ACK_VECTOR | X | | X | | 0 | 11.5 | + * | DCCPF_SEND_NDP_COUNT | | X | X | | 0 | 7.7.2 | + * | DCCPF_MIN_CSUM_COVER | X | | X | | 0 | 9.2.1 | + * | DCCPF_DATA_CHECKSUM | X | | X | | 0 | 9.3.1 | + * | DCCPF_SEND_LEV_RATE | X | | X | | 0 | 4342/8.4 | + * +--------------------------+----+-----+----+----+---------+-----------+ + */ +} dccp_feat_table[] = { + { DCCPF_CCID, FEAT_AT_TX, FEAT_SP, 2, dccp_hdlr_ccid }, + { DCCPF_SHORT_SEQNOS, FEAT_AT_TX, FEAT_SP, 0, NULL }, + { DCCPF_SEQUENCE_WINDOW, FEAT_AT_TX, FEAT_NN, 100, dccp_hdlr_seq_win }, + { DCCPF_ECN_INCAPABLE, FEAT_AT_RX, FEAT_SP, 0, NULL }, + { DCCPF_ACK_RATIO, FEAT_AT_TX, FEAT_NN, 2, dccp_hdlr_ack_ratio}, + { DCCPF_SEND_ACK_VECTOR, FEAT_AT_RX, FEAT_SP, 0, dccp_hdlr_ackvec }, + { DCCPF_SEND_NDP_COUNT, FEAT_AT_TX, FEAT_SP, 0, dccp_hdlr_ndp }, + { DCCPF_MIN_CSUM_COVER, FEAT_AT_RX, FEAT_SP, 0, dccp_hdlr_min_cscov}, + { DCCPF_DATA_CHECKSUM, FEAT_AT_RX, FEAT_SP, 0, NULL }, + { DCCPF_SEND_LEV_RATE, FEAT_AT_RX, FEAT_SP, 0, NULL }, +}; +#define DCCP_FEAT_SUPPORTED_MAX ARRAY_SIZE(dccp_feat_table) + +/** + * dccp_feat_index - Hash function to map feature number into array position + * Returns consecutive array index or -1 if the feature is not understood. + */ +static int dccp_feat_index(u8 feat_num) +{ + /* The first 9 entries are occupied by the types from RFC 4340, 6.4 */ + if (feat_num > DCCPF_RESERVED && feat_num <= DCCPF_DATA_CHECKSUM) + return feat_num - 1; + /* - * Now we have server preference list in spref and client preference in - * rpref + * Other features: add cases for new feature types here after adding + * them to the above table. */ - BUG_ON(spref == NULL); - BUG_ON(rpref == NULL); + switch (feat_num) { + case DCCPF_SEND_LEV_RATE: + return DCCP_FEAT_SUPPORTED_MAX - 1; + } + return -1; +} - /* FIXME sanity check vals */ +static u8 dccp_feat_type(u8 feat_num) +{ + int idx = dccp_feat_index(feat_num); - /* Are values in any order? XXX Lame "algorithm" here */ - for (i = 0; i < slen; i++) { - for (j = 0; j < rlen; j++) { - if (spref[i] == rpref[j]) { - res = &spref[i]; - break; - } - } - if (res) - break; - } + if (idx < 0) + return FEAT_UNKNOWN; + return dccp_feat_table[idx].reconciliation; +} - /* we didn't agree on anything */ - if (res == NULL) { - /* confirm previous value */ - switch (opt->dccpop_feat) { - case DCCPF_CCID: - /* XXX did i get this right? =P */ - if (opt->dccpop_type == DCCPO_CHANGE_L) - res = &dccp_msk(sk)->dccpms_tx_ccid; - else - res = &dccp_msk(sk)->dccpms_rx_ccid; - break; +static int dccp_feat_default_value(u8 feat_num) +{ + int idx = dccp_feat_index(feat_num); - default: - DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat); - /* XXX implement res */ - return -EFAULT; - } + return idx < 0 ? : dccp_feat_table[idx].default_value; +} - dccp_pr_debug("Don't agree... reconfirming %d\n", *res); - agree = 0; /* this is used for mandatory options... */ +/* + * Debugging and verbose-printing section + */ +static const char *dccp_feat_fname(const u8 feat) +{ + static const char *feature_names[] = { + [DCCPF_RESERVED] = "Reserved", + [DCCPF_CCID] = "CCID", + [DCCPF_SHORT_SEQNOS] = "Allow Short Seqnos", + [DCCPF_SEQUENCE_WINDOW] = "Sequence Window", + [DCCPF_ECN_INCAPABLE] = "ECN Incapable", + [DCCPF_ACK_RATIO] = "Ack Ratio", + [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector", + [DCCPF_SEND_NDP_COUNT] = "Send NDP Count", + [DCCPF_MIN_CSUM_COVER] = "Min. Csum Coverage", + [DCCPF_DATA_CHECKSUM] = "Send Data Checksum", + }; + if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC) + return feature_names[DCCPF_RESERVED]; + + if (feat == DCCPF_SEND_LEV_RATE) + return "Send Loss Event Rate"; + if (feat >= DCCPF_MIN_CCID_SPECIFIC) + return "CCID-specific"; + + return feature_names[feat]; +} + +static const char *dccp_feat_sname[] = { "DEFAULT", "INITIALISING", "CHANGING", + "UNSTABLE", "STABLE" }; + +#ifdef CONFIG_IP_DCCP_DEBUG +static const char *dccp_feat_oname(const u8 opt) +{ + switch (opt) { + case DCCPO_CHANGE_L: return "Change_L"; + case DCCPO_CONFIRM_L: return "Confirm_L"; + case DCCPO_CHANGE_R: return "Change_R"; + case DCCPO_CONFIRM_R: return "Confirm_R"; } + return NULL; +} - /* need to put result and our preference list */ - rlen = 1 + opt->dccpop_len; - rpref = kmalloc(rlen, GFP_ATOMIC); - if (rpref == NULL) - return -ENOMEM; +static void dccp_feat_printval(u8 feat_num, dccp_feat_val const *val) +{ + u8 i, type = dccp_feat_type(feat_num); + + if (val == NULL || (type == FEAT_SP && val->sp.vec == NULL)) + dccp_pr_debug_cat("(NULL)"); + else if (type == FEAT_SP) + for (i = 0; i < val->sp.len; i++) + dccp_pr_debug_cat("%s%u", i ? " " : "", val->sp.vec[i]); + else if (type == FEAT_NN) + dccp_pr_debug_cat("%llu", (unsigned long long)val->nn); + else + dccp_pr_debug_cat("unknown type %u", type); +} + +static void dccp_feat_printvals(u8 feat_num, u8 *list, u8 len) +{ + u8 type = dccp_feat_type(feat_num); + dccp_feat_val fval = { .sp.vec = list, .sp.len = len }; + + if (type == FEAT_NN) + fval.nn = dccp_decode_value_var(list, len); + dccp_feat_printval(feat_num, &fval); +} + +static void dccp_feat_print_entry(struct dccp_feat_entry const *entry) +{ + dccp_debug(" * %s %s = ", entry->is_local ? "local" : "remote", + dccp_feat_fname(entry->feat_num)); + dccp_feat_printval(entry->feat_num, &entry->val); + dccp_pr_debug_cat(", state=%s %s\n", dccp_feat_sname[entry->state], + entry->needs_confirm ? "(Confirm pending)" : ""); +} + +#define dccp_feat_print_opt(opt, feat, val, len, mandatory) do { \ + dccp_pr_debug("%s(%s, ", dccp_feat_oname(opt), dccp_feat_fname(feat));\ + dccp_feat_printvals(feat, val, len); \ + dccp_pr_debug_cat(") %s\n", mandatory ? "!" : ""); } while (0) + +#define dccp_feat_print_fnlist(fn_list) { \ + const struct dccp_feat_entry *___entry; \ + \ + dccp_pr_debug("List Dump:\n"); \ + list_for_each_entry(___entry, fn_list, node) \ + dccp_feat_print_entry(___entry); \ +} +#else /* ! CONFIG_IP_DCCP_DEBUG */ +#define dccp_feat_print_opt(opt, feat, val, len, mandatory) +#define dccp_feat_print_fnlist(fn_list) +#endif - *rpref = *res; - memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len); +static int __dccp_feat_activate(struct sock *sk, const int idx, + const bool is_local, dccp_feat_val const *fval) +{ + bool rx; + u64 val; + + if (idx < 0 || idx >= DCCP_FEAT_SUPPORTED_MAX) + return -1; + if (dccp_feat_table[idx].activation_hdlr == NULL) + return 0; - /* put it in the "confirm queue" */ - if (opt->dccpop_sc == NULL) { - opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC); - if (opt->dccpop_sc == NULL) { - kfree(rpref); - return -ENOMEM; + if (fval == NULL) { + val = dccp_feat_table[idx].default_value; + } else if (dccp_feat_table[idx].reconciliation == FEAT_SP) { + if (fval->sp.vec == NULL) { + /* + * This can happen when an empty Confirm is sent + * for an SP (i.e. known) feature. In this case + * we would be using the default anyway. + */ + DCCP_CRIT("Feature #%d undefined: using default", idx); + val = dccp_feat_table[idx].default_value; + } else { + val = fval->sp.vec[0]; } } else { - /* recycle the confirm slot */ - BUG_ON(opt->dccpop_sc->dccpoc_val == NULL); - kfree(opt->dccpop_sc->dccpoc_val); - dccp_pr_debug("recycling confirm slot\n"); - } - memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc)); - - opt->dccpop_sc->dccpoc_val = rpref; - opt->dccpop_sc->dccpoc_len = rlen; - - /* update the option on our side [we are about to send the confirm] */ - rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res); - if (rc) { - kfree(opt->dccpop_sc->dccpoc_val); - kfree(opt->dccpop_sc); - opt->dccpop_sc = NULL; - return rc; + val = fval->nn; } - dccp_pr_debug("Will confirm %d\n", *rpref); + /* Location is RX if this is a local-RX or remote-TX feature */ + rx = (is_local == (dccp_feat_table[idx].rxtx == FEAT_AT_RX)); - /* say we want to change to X but we just got a confirm X, suppress our - * change - */ - if (!opt->dccpop_conf) { - if (*opt->dccpop_val == *res) - opt->dccpop_conf = 1; - dccp_pr_debug("won't ask for change of same feature\n"); + dccp_debug(" -> activating %s %s, %sval=%llu\n", rx ? "RX" : "TX", + dccp_feat_fname(dccp_feat_table[idx].feat_num), + fval ? "" : "default ", (unsigned long long)val); + + return dccp_feat_table[idx].activation_hdlr(sk, val, rx); +} + +/** + * dccp_feat_activate - Activate feature value on socket + * @sk: fully connected DCCP socket (after handshake is complete) + * @feat_num: feature to activate, one of %dccp_feature_numbers + * @local: whether local (1) or remote (0) @feat_num is meant + * @fval: the value (SP or NN) to activate, or NULL to use the default value + * For general use this function is preferable over __dccp_feat_activate(). + */ +static int dccp_feat_activate(struct sock *sk, u8 feat_num, bool local, + dccp_feat_val const *fval) +{ + return __dccp_feat_activate(sk, dccp_feat_index(feat_num), local, fval); +} + +/* Test for "Req'd" feature (RFC 4340, 6.4) */ +static inline int dccp_feat_must_be_understood(u8 feat_num) +{ + return feat_num == DCCPF_CCID || feat_num == DCCPF_SHORT_SEQNOS || + feat_num == DCCPF_SEQUENCE_WINDOW; +} + +/* copy constructor, fval must not already contain allocated memory */ +static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len) +{ + fval->sp.len = len; + if (fval->sp.len > 0) { + fval->sp.vec = kmemdup(val, len, gfp_any()); + if (fval->sp.vec == NULL) { + fval->sp.len = 0; + return -ENOBUFS; + } } + return 0; +} - return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */ +static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val) +{ + if (unlikely(val == NULL)) + return; + if (dccp_feat_type(feat_num) == FEAT_SP) + kfree(val->sp.vec); + memset(val, 0, sizeof(*val)); } -static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) +static struct dccp_feat_entry * + dccp_feat_clone_entry(struct dccp_feat_entry const *original) { - struct dccp_minisock *dmsk = dccp_msk(sk); - struct dccp_opt_pend *opt; - int rc = 1; - u8 t; + struct dccp_feat_entry *new; + u8 type = dccp_feat_type(original->feat_num); - /* - * We received a CHANGE. We gotta match it against our own preference - * list. If we got a CHANGE_R it means it's a change for us, so we need - * to compare our CHANGE_L list. - */ - if (type == DCCPO_CHANGE_L) - t = DCCPO_CHANGE_R; - else - t = DCCPO_CHANGE_L; + if (type == FEAT_UNKNOWN) + return NULL; - /* find our preference list for this feature */ - list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { - if (opt->dccpop_type != t || opt->dccpop_feat != feature) - continue; + new = kmemdup(original, sizeof(struct dccp_feat_entry), gfp_any()); + if (new == NULL) + return NULL; - /* find the winner from the two preference lists */ - rc = dccp_feat_reconcile(sk, opt, val, len); - break; + if (type == FEAT_SP && dccp_feat_clone_sp_val(&new->val, + original->val.sp.vec, + original->val.sp.len)) { + kfree(new); + return NULL; } + return new; +} - /* We didn't deal with the change. This can happen if we have no - * preference list for the feature. In fact, it just shouldn't - * happen---if we understand a feature, we should have a preference list - * with at least the default value. - */ - BUG_ON(rc == 1); +static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry) +{ + if (entry != NULL) { + dccp_feat_val_destructor(entry->feat_num, &entry->val); + kfree(entry); + } +} - return rc; +/* + * List management functions + * + * Feature negotiation lists rely on and maintain the following invariants: + * - each feat_num in the list is known, i.e. we know its type and default value + * - each feat_num/is_local combination is unique (old entries are overwritten) + * - SP values are always freshly allocated + * - list is sorted in increasing order of feature number (faster lookup) + */ +static struct dccp_feat_entry *dccp_feat_list_lookup(struct list_head *fn_list, + u8 feat_num, bool is_local) +{ + struct dccp_feat_entry *entry; + + list_for_each_entry(entry, fn_list, node) + if (entry->feat_num == feat_num && entry->is_local == is_local) + return entry; + else if (entry->feat_num > feat_num) + break; + return NULL; } -static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) +/** + * dccp_feat_entry_new - Central list update routine (called by all others) + * @head: list to add to + * @feat: feature number + * @local: whether the local (1) or remote feature with number @feat is meant + * This is the only constructor and serves to ensure the above invariants. + */ +static struct dccp_feat_entry * + dccp_feat_entry_new(struct list_head *head, u8 feat, bool local) { - struct dccp_opt_pend *opt; - struct dccp_minisock *dmsk = dccp_msk(sk); - u8 *copy; - int rc; + struct dccp_feat_entry *entry; + + list_for_each_entry(entry, head, node) + if (entry->feat_num == feat && entry->is_local == local) { + dccp_feat_val_destructor(entry->feat_num, &entry->val); + return entry; + } else if (entry->feat_num > feat) { + head = &entry->node; + break; + } - /* NN features must be Change L (sec. 6.3.2) */ - if (type != DCCPO_CHANGE_L) { - dccp_pr_debug("received %s for NN feature %d\n", - dccp_feat_typename(type), feature); - return -EFAULT; + entry = kmalloc(sizeof(*entry), gfp_any()); + if (entry != NULL) { + entry->feat_num = feat; + entry->is_local = local; + list_add_tail(&entry->node, head); } + return entry; +} - /* XXX sanity check opt val */ +/** + * dccp_feat_push_change - Add/overwrite a Change option in the list + * @fn_list: feature-negotiation list to update + * @feat: one of %dccp_feature_numbers + * @local: whether local (1) or remote (0) @feat_num is meant + * @needs_mandatory: whether to use Mandatory feature negotiation options + * @fval: pointer to NN/SP value to be inserted (will be copied) + */ +static int dccp_feat_push_change(struct list_head *fn_list, u8 feat, u8 local, + u8 mandatory, dccp_feat_val *fval) +{ + struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local); - /* copy option so we can confirm it */ - opt = kzalloc(sizeof(*opt), GFP_ATOMIC); - if (opt == NULL) + if (new == NULL) return -ENOMEM; - copy = kmemdup(val, len, GFP_ATOMIC); - if (copy == NULL) { - kfree(opt); - return -ENOMEM; - } + new->feat_num = feat; + new->is_local = local; + new->state = FEAT_INITIALISING; + new->needs_confirm = 0; + new->empty_confirm = 0; + new->val = *fval; + new->needs_mandatory = mandatory; - opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */ - opt->dccpop_feat = feature; - opt->dccpop_val = copy; - opt->dccpop_len = len; + return 0; +} - /* change feature */ - rc = dccp_feat_update(sk, type, feature, *val); - if (rc) { - kfree(opt->dccpop_val); - kfree(opt); - return rc; - } +/** + * dccp_feat_push_confirm - Add a Confirm entry to the FN list + * @fn_list: feature-negotiation list to add to + * @feat: one of %dccp_feature_numbers + * @local: whether local (1) or remote (0) @feat_num is being confirmed + * @fval: pointer to NN/SP value to be inserted or NULL + * Returns 0 on success, a Reset code for further processing otherwise. + */ +static int dccp_feat_push_confirm(struct list_head *fn_list, u8 feat, u8 local, + dccp_feat_val *fval) +{ + struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local); - dccp_feat_debug(type, feature, *copy); + if (new == NULL) + return DCCP_RESET_CODE_TOO_BUSY; - list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf); + new->feat_num = feat; + new->is_local = local; + new->state = FEAT_STABLE; /* transition in 6.6.2 */ + new->needs_confirm = 1; + new->empty_confirm = (fval == NULL); + new->val.nn = 0; /* zeroes the whole structure */ + if (!new->empty_confirm) + new->val = *fval; + new->needs_mandatory = 0; return 0; } -static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk, - u8 type, u8 feature) +static int dccp_push_empty_confirm(struct list_head *fn_list, u8 feat, u8 local) { - /* XXX check if other confirms for that are queued and recycle slot */ - struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC); + return dccp_feat_push_confirm(fn_list, feat, local, NULL); +} - if (opt == NULL) { - /* XXX what do we do? Ignoring should be fine. It's a change - * after all =P - */ - return; - } +static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry) +{ + list_del(&entry->node); + dccp_feat_entry_destructor(entry); +} - switch (type) { - case DCCPO_CHANGE_L: - opt->dccpop_type = DCCPO_CONFIRM_R; - break; - case DCCPO_CHANGE_R: - opt->dccpop_type = DCCPO_CONFIRM_L; - break; - default: - DCCP_WARN("invalid type %d\n", type); - kfree(opt); - return; +void dccp_feat_list_purge(struct list_head *fn_list) +{ + struct dccp_feat_entry *entry, *next; + + list_for_each_entry_safe(entry, next, fn_list, node) + dccp_feat_entry_destructor(entry); + INIT_LIST_HEAD(fn_list); +} +EXPORT_SYMBOL_GPL(dccp_feat_list_purge); + +/* generate @to as full clone of @from - @to must not contain any nodes */ +int dccp_feat_clone_list(struct list_head const *from, struct list_head *to) +{ + struct dccp_feat_entry *entry, *new; + + INIT_LIST_HEAD(to); + list_for_each_entry(entry, from, node) { + new = dccp_feat_clone_entry(entry); + if (new == NULL) + goto cloning_failed; + list_add_tail(&new->node, to); } - opt->dccpop_feat = feature; - opt->dccpop_val = NULL; - opt->dccpop_len = 0; + return 0; - /* change feature */ - dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature); +cloning_failed: + dccp_feat_list_purge(to); + return -ENOMEM; +} - list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf); +/** + * dccp_feat_valid_nn_length - Enforce length constraints on NN options + * Length is between 0 and %DCCP_OPTVAL_MAXLEN. Used for outgoing packets only, + * incoming options are accepted as long as their values are valid. + */ +static u8 dccp_feat_valid_nn_length(u8 feat_num) +{ + if (feat_num == DCCPF_ACK_RATIO) /* RFC 4340, 11.3 and 6.6.8 */ + return 2; + if (feat_num == DCCPF_SEQUENCE_WINDOW) /* RFC 4340, 7.5.2 and 6.5 */ + return 6; + return 0; } -static void dccp_feat_flush_confirm(struct sock *sk) +static u8 dccp_feat_is_valid_nn_val(u8 feat_num, u64 val) { - struct dccp_minisock *dmsk = dccp_msk(sk); - /* Check if there is anything to confirm in the first place */ - int yes = !list_empty(&dmsk->dccpms_conf); + switch (feat_num) { + case DCCPF_ACK_RATIO: + return val <= DCCPF_ACK_RATIO_MAX; + case DCCPF_SEQUENCE_WINDOW: + return val >= DCCPF_SEQ_WMIN && val <= DCCPF_SEQ_WMAX; + } + return 0; /* feature unknown - so we can't tell */ +} - if (!yes) { - struct dccp_opt_pend *opt; +/* check that SP values are within the ranges defined in RFC 4340 */ +static u8 dccp_feat_is_valid_sp_val(u8 feat_num, u8 val) +{ + switch (feat_num) { + case DCCPF_CCID: + return val == DCCPC_CCID2 || val == DCCPC_CCID3; + /* Type-check Boolean feature values: */ + case DCCPF_SHORT_SEQNOS: + case DCCPF_ECN_INCAPABLE: + case DCCPF_SEND_ACK_VECTOR: + case DCCPF_SEND_NDP_COUNT: + case DCCPF_DATA_CHECKSUM: + case DCCPF_SEND_LEV_RATE: + return val < 2; + case DCCPF_MIN_CSUM_COVER: + return val < 16; + } + return 0; /* feature unknown */ +} + +static u8 dccp_feat_sp_list_ok(u8 feat_num, u8 const *sp_list, u8 sp_len) +{ + if (sp_list == NULL || sp_len < 1) + return 0; + while (sp_len--) + if (!dccp_feat_is_valid_sp_val(feat_num, *sp_list++)) + return 0; + return 1; +} - list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { - if (opt->dccpop_conf) { - yes = 1; - break; +/** + * dccp_feat_insert_opts - Generate FN options from current list state + * @skb: next sk_buff to be sent to the peer + * @dp: for client during handshake and general negotiation + * @dreq: used by the server only (all Changes/Confirms in LISTEN/RESPOND) + */ +int dccp_feat_insert_opts(struct dccp_sock *dp, struct dccp_request_sock *dreq, + struct sk_buff *skb) +{ + struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg; + struct dccp_feat_entry *pos, *next; + u8 opt, type, len, *ptr, nn_in_nbo[DCCP_OPTVAL_MAXLEN]; + bool rpt; + + /* put entries into @skb in the order they appear in the list */ + list_for_each_entry_safe_reverse(pos, next, fn, node) { + opt = dccp_feat_genopt(pos); + type = dccp_feat_type(pos->feat_num); + rpt = false; + + if (pos->empty_confirm) { + len = 0; + ptr = NULL; + } else { + if (type == FEAT_SP) { + len = pos->val.sp.len; + ptr = pos->val.sp.vec; + rpt = pos->needs_confirm; + } else if (type == FEAT_NN) { + len = dccp_feat_valid_nn_length(pos->feat_num); + ptr = nn_in_nbo; + dccp_encode_value_var(pos->val.nn, ptr, len); + } else { + DCCP_BUG("unknown feature %u", pos->feat_num); + return -1; } } + dccp_feat_print_opt(opt, pos->feat_num, ptr, len, 0); + + if (dccp_insert_fn_opt(skb, opt, pos->feat_num, ptr, len, rpt)) + return -1; + if (pos->needs_mandatory && dccp_insert_option_mandatory(skb)) + return -1; + /* + * Enter CHANGING after transmitting the Change option (6.6.2). + */ + if (pos->state == FEAT_INITIALISING) + pos->state = FEAT_CHANGING; } + return 0; +} - if (!yes) - return; +/** + * __feat_register_nn - Register new NN value on socket + * @fn: feature-negotiation list to register with + * @feat: an NN feature from %dccp_feature_numbers + * @mandatory: use Mandatory option if 1 + * @nn_val: value to register (restricted to 4 bytes) + * Note that NN features are local by definition (RFC 4340, 6.3.2). + */ +static int __feat_register_nn(struct list_head *fn, u8 feat, + u8 mandatory, u64 nn_val) +{ + dccp_feat_val fval = { .nn = nn_val }; - /* OK there is something to confirm... */ - /* XXX check if packet is in flight? Send delayed ack?? */ - if (sk->sk_state == DCCP_OPEN) - dccp_send_ack(sk); + if (dccp_feat_type(feat) != FEAT_NN || + !dccp_feat_is_valid_nn_val(feat, nn_val)) + return -EINVAL; + + /* Don't bother with default values, they will be activated anyway. */ + if (nn_val - (u64)dccp_feat_default_value(feat) == 0) + return 0; + + return dccp_feat_push_change(fn, feat, 1, mandatory, &fval); } -int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) +/** + * __feat_register_sp - Register new SP value/list on socket + * @fn: feature-negotiation list to register with + * @feat: an SP feature from %dccp_feature_numbers + * @is_local: whether the local (1) or the remote (0) @feat is meant + * @mandatory: use Mandatory option if 1 + * @sp_val: SP value followed by optional preference list + * @sp_len: length of @sp_val in bytes + */ +static int __feat_register_sp(struct list_head *fn, u8 feat, u8 is_local, + u8 mandatory, u8 const *sp_val, u8 sp_len) { - int rc; + dccp_feat_val fval; - dccp_feat_debug(type, feature, *val); + if (dccp_feat_type(feat) != FEAT_SP || + !dccp_feat_sp_list_ok(feat, sp_val, sp_len)) + return -EINVAL; - /* figure out if it's SP or NN feature */ - switch (feature) { - /* deal with SP features */ - case DCCPF_CCID: - rc = dccp_feat_sp(sk, type, feature, val, len); - break; + /* Avoid negotiating alien CCIDs by only advertising supported ones */ + if (feat == DCCPF_CCID && !ccid_support_check(sp_val, sp_len)) + return -EOPNOTSUPP; - /* deal with NN features */ - case DCCPF_ACK_RATIO: - rc = dccp_feat_nn(sk, type, feature, val, len); - break; + if (dccp_feat_clone_sp_val(&fval, sp_val, sp_len)) + return -ENOMEM; - /* XXX implement other features */ - default: - dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n", - dccp_feat_typename(type), feature); - rc = -EFAULT; - break; + return dccp_feat_push_change(fn, feat, is_local, mandatory, &fval); +} + +/** + * dccp_feat_register_sp - Register requests to change SP feature values + * @sk: client or listening socket + * @feat: one of %dccp_feature_numbers + * @is_local: whether the local (1) or remote (0) @feat is meant + * @list: array of preferred values, in descending order of preference + * @len: length of @list in bytes + */ +int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local, + u8 const *list, u8 len) +{ /* any changes must be registered before establishing the connection */ + if (sk->sk_state != DCCP_CLOSED) + return -EISCONN; + if (dccp_feat_type(feat) != FEAT_SP) + return -EINVAL; + return __feat_register_sp(&dccp_sk(sk)->dccps_featneg, feat, is_local, + 0, list, len); +} + +/* Analogous to dccp_feat_register_sp(), but for non-negotiable values */ +int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val) +{ + /* any changes must be registered before establishing the connection */ + if (sk->sk_state != DCCP_CLOSED) + return -EISCONN; + if (dccp_feat_type(feat) != FEAT_NN) + return -EINVAL; + return __feat_register_nn(&dccp_sk(sk)->dccps_featneg, feat, 0, val); +} + +/** + * dccp_feat_signal_nn_change - Update NN values for an established connection + * @sk: DCCP socket of an established connection + * @feat: NN feature number from %dccp_feature_numbers + * @nn_val: the new value to use + * This function is used to communicate NN updates out-of-band. The difference + * to feature negotiation during connection setup is that values are activated + * immediately after validation, i.e. we don't wait for the Confirm: either the + * value is accepted by the peer (and then the waiting is futile), or it is not + * (Reset or empty Confirm). We don't accept empty Confirms - transmitted values + * are validated, and the peer "MUST accept any valid value" (RFC 4340, 6.3.2). + */ +int dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val) +{ + struct list_head *fn = &dccp_sk(sk)->dccps_featneg; + dccp_feat_val fval = { .nn = nn_val }; + struct dccp_feat_entry *entry; + + if (sk->sk_state != DCCP_OPEN && sk->sk_state != DCCP_PARTOPEN) + return 0; + + if (dccp_feat_type(feat) != FEAT_NN || + !dccp_feat_is_valid_nn_val(feat, nn_val)) + return -EINVAL; + + entry = dccp_feat_list_lookup(fn, feat, 1); + if (entry != NULL) { + dccp_pr_debug("Ignoring %llu, entry %llu exists in state %s\n", + (unsigned long long)nn_val, + (unsigned long long)entry->val.nn, + dccp_feat_sname[entry->state]); + return 0; } - /* check if there were problems changing features */ - if (rc) { - /* If we don't agree on SP, we sent a confirm for old value. - * However we propagate rc to caller in case option was - * mandatory + if (dccp_feat_activate(sk, feat, 1, &fval)) + return -EADV; + + inet_csk_schedule_ack(sk); + return dccp_feat_push_change(fn, feat, 1, 0, &fval); +} +EXPORT_SYMBOL_GPL(dccp_feat_signal_nn_change); + +/* + * Tracking features whose value depend on the choice of CCID + * + * This is designed with an extension in mind so that a list walk could be done + * before activating any features. However, the existing framework was found to + * work satisfactorily up until now, the automatic verification is left open. + * When adding new CCIDs, add a corresponding dependency table here. + */ +static const struct ccid_dependency *dccp_feat_ccid_deps(u8 ccid, bool is_local) +{ + static const struct ccid_dependency ccid2_dependencies[2][2] = { + /* + * CCID2 mandates Ack Vectors (RFC 4341, 4.): as CCID is a TX + * feature and Send Ack Vector is an RX feature, `is_local' + * needs to be reversed. */ - if (rc != DCCP_FEAT_SP_NOAGREE) - dccp_feat_empty_confirm(dccp_msk(sk), type, feature); + { /* Dependencies of the receiver-side (remote) CCID2 */ + { + .dependent_feat = DCCPF_SEND_ACK_VECTOR, + .is_local = true, + .is_mandatory = true, + .val = 1 + }, + { 0, 0, 0, 0 } + }, + { /* Dependencies of the sender-side (local) CCID2 */ + { + .dependent_feat = DCCPF_SEND_ACK_VECTOR, + .is_local = false, + .is_mandatory = true, + .val = 1 + }, + { 0, 0, 0, 0 } + } + }; + static const struct ccid_dependency ccid3_dependencies[2][5] = { + { /* + * Dependencies of the receiver-side CCID3 + */ + { /* locally disable Ack Vectors */ + .dependent_feat = DCCPF_SEND_ACK_VECTOR, + .is_local = true, + .is_mandatory = false, + .val = 0 + }, + { /* see below why Send Loss Event Rate is on */ + .dependent_feat = DCCPF_SEND_LEV_RATE, + .is_local = true, + .is_mandatory = true, + .val = 1 + }, + { /* NDP Count is needed as per RFC 4342, 6.1.1 */ + .dependent_feat = DCCPF_SEND_NDP_COUNT, + .is_local = false, + .is_mandatory = true, + .val = 1 + }, + { 0, 0, 0, 0 }, + }, + { /* + * CCID3 at the TX side: we request that the HC-receiver + * will not send Ack Vectors (they will be ignored, so + * Mandatory is not set); we enable Send Loss Event Rate + * (Mandatory since the implementation does not support + * the Loss Intervals option of RFC 4342, 8.6). + * The last two options are for peer's information only. + */ + { + .dependent_feat = DCCPF_SEND_ACK_VECTOR, + .is_local = false, + .is_mandatory = false, + .val = 0 + }, + { + .dependent_feat = DCCPF_SEND_LEV_RATE, + .is_local = false, + .is_mandatory = true, + .val = 1 + }, + { /* this CCID does not support Ack Ratio */ + .dependent_feat = DCCPF_ACK_RATIO, + .is_local = true, + .is_mandatory = false, + .val = 0 + }, + { /* tell receiver we are sending NDP counts */ + .dependent_feat = DCCPF_SEND_NDP_COUNT, + .is_local = true, + .is_mandatory = false, + .val = 1 + }, + { 0, 0, 0, 0 } + } + }; + switch (ccid) { + case DCCPC_CCID2: + return ccid2_dependencies[is_local]; + case DCCPC_CCID3: + return ccid3_dependencies[is_local]; + default: + return NULL; } +} - /* generate the confirm [if required] */ - dccp_feat_flush_confirm(sk); - +/** + * dccp_feat_propagate_ccid - Resolve dependencies of features on choice of CCID + * @fn: feature-negotiation list to update + * @id: CCID number to track + * @is_local: whether TX CCID (1) or RX CCID (0) is meant + * This function needs to be called after registering all other features. + */ +static int dccp_feat_propagate_ccid(struct list_head *fn, u8 id, bool is_local) +{ + const struct ccid_dependency *table = dccp_feat_ccid_deps(id, is_local); + int i, rc = (table == NULL); + + for (i = 0; rc == 0 && table[i].dependent_feat != DCCPF_RESERVED; i++) + if (dccp_feat_type(table[i].dependent_feat) == FEAT_SP) + rc = __feat_register_sp(fn, table[i].dependent_feat, + table[i].is_local, + table[i].is_mandatory, + &table[i].val, 1); + else + rc = __feat_register_nn(fn, table[i].dependent_feat, + table[i].is_mandatory, + table[i].val); return rc; } -EXPORT_SYMBOL_GPL(dccp_feat_change_recv); +/** + * dccp_feat_finalise_settings - Finalise settings before starting negotiation + * @dp: client or listening socket (settings will be inherited) + * This is called after all registrations (socket initialisation, sysctls, and + * sockopt calls), and before sending the first packet containing Change options + * (ie. client-Request or server-Response), to ensure internal consistency. + */ +int dccp_feat_finalise_settings(struct dccp_sock *dp) +{ + struct list_head *fn = &dp->dccps_featneg; + struct dccp_feat_entry *entry; + int i = 2, ccids[2] = { -1, -1 }; + + /* + * Propagating CCIDs: + * 1) not useful to propagate CCID settings if this host advertises more + * than one CCID: the choice of CCID may still change - if this is + * the client, or if this is the server and the client sends + * singleton CCID values. + * 2) since is that propagate_ccid changes the list, we defer changing + * the sorted list until after the traversal. + */ + list_for_each_entry(entry, fn, node) + if (entry->feat_num == DCCPF_CCID && entry->val.sp.len == 1) + ccids[entry->is_local] = entry->val.sp.vec[0]; + while (i--) + if (ccids[i] > 0 && dccp_feat_propagate_ccid(fn, ccids[i], i)) + return -1; + dccp_feat_print_fnlist(fn); + return 0; +} -int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, - u8 *val, u8 len) +/** + * dccp_feat_server_ccid_dependencies - Resolve CCID-dependent features + * It is the server which resolves the dependencies once the CCID has been + * fully negotiated. If no CCID has been negotiated, it uses the default CCID. + */ +int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq) { - u8 t; - struct dccp_opt_pend *opt; - struct dccp_minisock *dmsk = dccp_msk(sk); - int found = 0; - int all_confirmed = 1; + struct list_head *fn = &dreq->dreq_featneg; + struct dccp_feat_entry *entry; + u8 is_local, ccid; - dccp_feat_debug(type, feature, *val); + for (is_local = 0; is_local <= 1; is_local++) { + entry = dccp_feat_list_lookup(fn, DCCPF_CCID, is_local); - /* locate our change request */ - switch (type) { - case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break; - case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break; - default: DCCP_WARN("invalid type %d\n", type); - return 1; + if (entry != NULL && !entry->empty_confirm) + ccid = entry->val.sp.vec[0]; + else + ccid = dccp_feat_default_value(DCCPF_CCID); + if (dccp_feat_propagate_ccid(fn, ccid, is_local)) + return -1; } - /* XXX sanity check feature value */ + return 0; +} - list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { - if (!opt->dccpop_conf && opt->dccpop_type == t && - opt->dccpop_feat == feature) { - found = 1; - dccp_pr_debug("feature %d found\n", opt->dccpop_feat); +/* Select the first entry in @servlist that also occurs in @clilist (6.3.1) */ +static int dccp_feat_preflist_match(u8 *servlist, u8 slen, u8 *clilist, u8 clen) +{ + u8 c, s; - /* XXX do sanity check */ + for (s = 0; s < slen; s++) + for (c = 0; c < clen; c++) + if (servlist[s] == clilist[c]) + return servlist[s]; + return -1; +} - opt->dccpop_conf = 1; +/** + * dccp_feat_prefer - Move preferred entry to the start of array + * Reorder the @array_len elements in @array so that @preferred_value comes + * first. Returns >0 to indicate that @preferred_value does occur in @array. + */ +static u8 dccp_feat_prefer(u8 preferred_value, u8 *array, u8 array_len) +{ + u8 i, does_occur = 0; - /* We got a confirmation---change the option */ - dccp_feat_update(sk, opt->dccpop_type, - opt->dccpop_feat, *val); + if (array != NULL) { + for (i = 0; i < array_len; i++) + if (array[i] == preferred_value) { + array[i] = array[0]; + does_occur++; + } + if (does_occur) + array[0] = preferred_value; + } + return does_occur; +} - /* XXX check the return value of dccp_feat_update */ - break; - } +/** + * dccp_feat_reconcile - Reconcile SP preference lists + * @fval: SP list to reconcile into + * @arr: received SP preference list + * @len: length of @arr in bytes + * @is_server: whether this side is the server (and @fv is the server's list) + * @reorder: whether to reorder the list in @fv after reconciling with @arr + * When successful, > 0 is returned and the reconciled list is in @fval. + * A value of 0 means that negotiation failed (no shared entry). + */ +static int dccp_feat_reconcile(dccp_feat_val *fv, u8 *arr, u8 len, + bool is_server, bool reorder) +{ + int rc; - if (!opt->dccpop_conf) - all_confirmed = 0; + if (!fv->sp.vec || !arr) { + DCCP_CRIT("NULL feature value or array"); + return 0; } - /* fix re-transmit timer */ - /* XXX gotta make sure that no option negotiation occurs during - * connection shutdown. Consider that the CLOSEREQ is sent and timer is - * on. if all options are confirmed it might kill timer which should - * remain alive until close is received. - */ - if (all_confirmed) { - dccp_pr_debug("clear feat negotiation timer %p\n", sk); - inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); - } + if (is_server) + rc = dccp_feat_preflist_match(fv->sp.vec, fv->sp.len, arr, len); + else + rc = dccp_feat_preflist_match(arr, len, fv->sp.vec, fv->sp.len); - if (!found) - dccp_pr_debug("%s(%d, ...) never requested\n", - dccp_feat_typename(type), feature); - return 0; -} + if (!reorder) + return rc; + if (rc < 0) + return 0; -EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv); + /* + * Reorder list: used for activating features and in dccp_insert_fn_opt. + */ + return dccp_feat_prefer(rc, fv->sp.vec, fv->sp.len); +} -void dccp_feat_clean(struct dccp_minisock *dmsk) +/** + * dccp_feat_change_recv - Process incoming ChangeL/R options + * @fn: feature-negotiation list to update + * @is_mandatory: whether the Change was preceded by a Mandatory option + * @opt: %DCCPO_CHANGE_L or %DCCPO_CHANGE_R + * @feat: one of %dccp_feature_numbers + * @val: NN value or SP value/preference list + * @len: length of @val in bytes + * @server: whether this node is the server (1) or the client (0) + */ +static u8 dccp_feat_change_recv(struct list_head *fn, u8 is_mandatory, u8 opt, + u8 feat, u8 *val, u8 len, const bool server) { - struct dccp_opt_pend *opt, *next; + u8 defval, type = dccp_feat_type(feat); + const bool local = (opt == DCCPO_CHANGE_R); + struct dccp_feat_entry *entry; + dccp_feat_val fval; + + if (len == 0 || type == FEAT_UNKNOWN) /* 6.1 and 6.6.8 */ + goto unknown_feature_or_value; + + dccp_feat_print_opt(opt, feat, val, len, is_mandatory); + + /* + * Negotiation of NN features: Change R is invalid, so there is no + * simultaneous negotiation; hence we do not look up in the list. + */ + if (type == FEAT_NN) { + if (local || len > sizeof(fval.nn)) + goto unknown_feature_or_value; - list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending, - dccpop_node) { - BUG_ON(opt->dccpop_val == NULL); - kfree(opt->dccpop_val); + /* 6.3.2: "The feature remote MUST accept any valid value..." */ + fval.nn = dccp_decode_value_var(val, len); + if (!dccp_feat_is_valid_nn_val(feat, fval.nn)) + goto unknown_feature_or_value; - if (opt->dccpop_sc != NULL) { - BUG_ON(opt->dccpop_sc->dccpoc_val == NULL); - kfree(opt->dccpop_sc->dccpoc_val); - kfree(opt->dccpop_sc); + return dccp_feat_push_confirm(fn, feat, local, &fval); + } + + /* + * Unidirectional/simultaneous negotiation of SP features (6.3.1) + */ + entry = dccp_feat_list_lookup(fn, feat, local); + if (entry == NULL) { + /* + * No particular preferences have been registered. We deal with + * this situation by assuming that all valid values are equally + * acceptable, and apply the following checks: + * - if the peer's list is a singleton, we accept a valid value; + * - if we are the server, we first try to see if the peer (the + * client) advertises the default value. If yes, we use it, + * otherwise we accept the preferred value; + * - else if we are the client, we use the first list element. + */ + if (dccp_feat_clone_sp_val(&fval, val, 1)) + return DCCP_RESET_CODE_TOO_BUSY; + + if (len > 1 && server) { + defval = dccp_feat_default_value(feat); + if (dccp_feat_preflist_match(&defval, 1, val, len) > -1) + fval.sp.vec[0] = defval; + } else if (!dccp_feat_is_valid_sp_val(feat, fval.sp.vec[0])) { + kfree(fval.sp.vec); + goto unknown_feature_or_value; + } + + /* Treat unsupported CCIDs like invalid values */ + if (feat == DCCPF_CCID && !ccid_support_check(fval.sp.vec, 1)) { + kfree(fval.sp.vec); + goto not_valid_or_not_known; } - kfree(opt); + return dccp_feat_push_confirm(fn, feat, local, &fval); + + } else if (entry->state == FEAT_UNSTABLE) { /* 6.6.2 */ + return 0; } - INIT_LIST_HEAD(&dmsk->dccpms_pending); - list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) { - BUG_ON(opt == NULL); - if (opt->dccpop_val != NULL) - kfree(opt->dccpop_val); - kfree(opt); + if (dccp_feat_reconcile(&entry->val, val, len, server, true)) { + entry->empty_confirm = 0; + } else if (is_mandatory) { + return DCCP_RESET_CODE_MANDATORY_ERROR; + } else if (entry->state == FEAT_INITIALISING) { + /* + * Failed simultaneous negotiation (server only): try to `save' + * the connection by checking whether entry contains the default + * value for @feat. If yes, send an empty Confirm to signal that + * the received Change was not understood - which implies using + * the default value. + * If this also fails, we use Reset as the last resort. + */ + WARN_ON(!server); + defval = dccp_feat_default_value(feat); + if (!dccp_feat_reconcile(&entry->val, &defval, 1, server, true)) + return DCCP_RESET_CODE_OPTION_ERROR; + entry->empty_confirm = 1; } - INIT_LIST_HEAD(&dmsk->dccpms_conf); -} + entry->needs_confirm = 1; + entry->needs_mandatory = 0; + entry->state = FEAT_STABLE; + return 0; -EXPORT_SYMBOL_GPL(dccp_feat_clean); +unknown_feature_or_value: + if (!is_mandatory) + return dccp_push_empty_confirm(fn, feat, local); -/* this is to be called only when a listening sock creates its child. It is - * assumed by the function---the confirm is not duplicated, but rather it is - * "passed on". +not_valid_or_not_known: + return is_mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR + : DCCP_RESET_CODE_OPTION_ERROR; +} + +/** + * dccp_feat_confirm_recv - Process received Confirm options + * @fn: feature-negotiation list to update + * @is_mandatory: whether @opt was preceded by a Mandatory option + * @opt: %DCCPO_CONFIRM_L or %DCCPO_CONFIRM_R + * @feat: one of %dccp_feature_numbers + * @val: NN value or SP value/preference list + * @len: length of @val in bytes + * @server: whether this node is server (1) or client (0) */ -int dccp_feat_clone(struct sock *oldsk, struct sock *newsk) +static u8 dccp_feat_confirm_recv(struct list_head *fn, u8 is_mandatory, u8 opt, + u8 feat, u8 *val, u8 len, const bool server) { - struct dccp_minisock *olddmsk = dccp_msk(oldsk); - struct dccp_minisock *newdmsk = dccp_msk(newsk); - struct dccp_opt_pend *opt; - int rc = 0; + u8 *plist, plen, type = dccp_feat_type(feat); + const bool local = (opt == DCCPO_CONFIRM_R); + struct dccp_feat_entry *entry = dccp_feat_list_lookup(fn, feat, local); - INIT_LIST_HEAD(&newdmsk->dccpms_pending); - INIT_LIST_HEAD(&newdmsk->dccpms_conf); + dccp_feat_print_opt(opt, feat, val, len, is_mandatory); - list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) { - struct dccp_opt_pend *newopt; - /* copy the value of the option */ - u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC); + if (entry == NULL) { /* nothing queued: ignore or handle error */ + if (is_mandatory && type == FEAT_UNKNOWN) + return DCCP_RESET_CODE_MANDATORY_ERROR; - if (val == NULL) - goto out_clean; - - newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC); - if (newopt == NULL) { - kfree(val); - goto out_clean; - } + if (!local && type == FEAT_NN) /* 6.3.2 */ + goto confirmation_failed; + return 0; + } - /* insert the option */ - newopt->dccpop_val = val; - list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending); + if (entry->state != FEAT_CHANGING) /* 6.6.2 */ + return 0; - /* XXX what happens with backlogs and multiple connections at - * once... + if (len == 0) { + if (dccp_feat_must_be_understood(feat)) /* 6.6.7 */ + goto confirmation_failed; + /* + * Empty Confirm during connection setup: this means reverting + * to the `old' value, which in this case is the default. Since + * we handle default values automatically when no other values + * have been set, we revert to the old value by removing this + * entry from the list. */ - /* the master socket no longer needs to worry about confirms */ - opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */ + dccp_feat_list_pop(entry); + return 0; + } + + if (type == FEAT_NN) { + if (len > sizeof(entry->val.nn)) + goto confirmation_failed; + + if (entry->val.nn == dccp_decode_value_var(val, len)) + goto confirmation_succeeded; + + DCCP_WARN("Bogus Confirm for non-existing value\n"); + goto confirmation_failed; + } - /* reset state for a new socket */ - opt->dccpop_conf = 0; + /* + * Parsing SP Confirms: the first element of @val is the preferred + * SP value which the peer confirms, the remainder depends on @len. + * Note that only the confirmed value need to be a valid SP value. + */ + if (!dccp_feat_is_valid_sp_val(feat, *val)) + goto confirmation_failed; + + if (len == 1) { /* peer didn't supply a preference list */ + plist = val; + plen = len; + } else { /* preferred value + preference list */ + plist = val + 1; + plen = len - 1; } - /* XXX not doing anything about the conf queue */ + /* Check whether the peer got the reconciliation right (6.6.8) */ + if (dccp_feat_reconcile(&entry->val, plist, plen, server, 0) != *val) { + DCCP_WARN("Confirm selected the wrong value %u\n", *val); + return DCCP_RESET_CODE_OPTION_ERROR; + } + entry->val.sp.vec[0] = *val; -out: - return rc; +confirmation_succeeded: + entry->state = FEAT_STABLE; + return 0; -out_clean: - dccp_feat_clean(newdmsk); - rc = -ENOMEM; - goto out; +confirmation_failed: + DCCP_WARN("Confirmation failed\n"); + return is_mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR + : DCCP_RESET_CODE_OPTION_ERROR; } -EXPORT_SYMBOL_GPL(dccp_feat_clone); +/** + * dccp_feat_handle_nn_established - Fast-path reception of NN options + * @sk: socket of an established DCCP connection + * @mandatory: whether @opt was preceded by a Mandatory option + * @opt: %DCCPO_CHANGE_L | %DCCPO_CONFIRM_R (NN only) + * @feat: NN number, one of %dccp_feature_numbers + * @val: NN value + * @len: length of @val in bytes + * This function combines the functionality of change_recv/confirm_recv, with + * the following differences (reset codes are the same): + * - cleanup after receiving the Confirm; + * - values are directly activated after successful parsing; + * - deliberately restricted to NN features. + * The restriction to NN features is essential since SP features can have non- + * predictable outcomes (depending on the remote configuration), and are inter- + * dependent (CCIDs for instance cause further dependencies). + */ +static u8 dccp_feat_handle_nn_established(struct sock *sk, u8 mandatory, u8 opt, + u8 feat, u8 *val, u8 len) +{ + struct list_head *fn = &dccp_sk(sk)->dccps_featneg; + const bool local = (opt == DCCPO_CONFIRM_R); + struct dccp_feat_entry *entry; + u8 type = dccp_feat_type(feat); + dccp_feat_val fval; + + dccp_feat_print_opt(opt, feat, val, len, mandatory); + + /* Ignore non-mandatory unknown and non-NN features */ + if (type == FEAT_UNKNOWN) { + if (local && !mandatory) + return 0; + goto fast_path_unknown; + } else if (type != FEAT_NN) { + return 0; + } + + /* + * We don't accept empty Confirms, since in fast-path feature + * negotiation the values are enabled immediately after sending + * the Change option. + * Empty Changes on the other hand are invalid (RFC 4340, 6.1). + */ + if (len == 0 || len > sizeof(fval.nn)) + goto fast_path_unknown; + + if (opt == DCCPO_CHANGE_L) { + fval.nn = dccp_decode_value_var(val, len); + if (!dccp_feat_is_valid_nn_val(feat, fval.nn)) + goto fast_path_unknown; + + if (dccp_feat_push_confirm(fn, feat, local, &fval) || + dccp_feat_activate(sk, feat, local, &fval)) + return DCCP_RESET_CODE_TOO_BUSY; + + /* set the `Ack Pending' flag to piggyback a Confirm */ + inet_csk_schedule_ack(sk); + + } else if (opt == DCCPO_CONFIRM_R) { + entry = dccp_feat_list_lookup(fn, feat, local); + if (entry == NULL || entry->state != FEAT_CHANGING) + return 0; + + fval.nn = dccp_decode_value_var(val, len); + if (fval.nn != entry->val.nn) { + DCCP_WARN("Bogus Confirm for non-existing value\n"); + goto fast_path_failed; + } + + /* It has been confirmed - so remove the entry */ + dccp_feat_list_pop(entry); + + } else { + DCCP_WARN("Received illegal option %u\n", opt); + goto fast_path_failed; + } + return 0; + +fast_path_unknown: + if (!mandatory) + return dccp_push_empty_confirm(fn, feat, local); + +fast_path_failed: + return mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR + : DCCP_RESET_CODE_OPTION_ERROR; +} -static int __dccp_feat_init(struct dccp_minisock *dmsk, u8 type, u8 feat, - u8 *val, u8 len) +/** + * dccp_feat_parse_options - Process Feature-Negotiation Options + * @sk: for general use and used by the client during connection setup + * @dreq: used by the server during connection setup + * @mandatory: whether @opt was preceded by a Mandatory option + * @opt: %DCCPO_CHANGE_L | %DCCPO_CHANGE_R | %DCCPO_CONFIRM_L | %DCCPO_CONFIRM_R + * @feat: one of %dccp_feature_numbers + * @val: value contents of @opt + * @len: length of @val in bytes + * Returns 0 on success, a Reset code for ending the connection otherwise. + */ +int dccp_feat_parse_options(struct sock *sk, struct dccp_request_sock *dreq, + u8 mandatory, u8 opt, u8 feat, u8 *val, u8 len) { - int rc = -ENOMEM; - u8 *copy = kmemdup(val, len, GFP_KERNEL); + struct dccp_sock *dp = dccp_sk(sk); + struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg; + bool server = false; - if (copy != NULL) { - rc = dccp_feat_change(dmsk, type, feat, copy, len, GFP_KERNEL); - if (rc) - kfree(copy); + switch (sk->sk_state) { + /* + * Negotiation during connection setup + */ + case DCCP_LISTEN: + server = true; /* fall through */ + case DCCP_REQUESTING: + switch (opt) { + case DCCPO_CHANGE_L: + case DCCPO_CHANGE_R: + return dccp_feat_change_recv(fn, mandatory, opt, feat, + val, len, server); + case DCCPO_CONFIRM_R: + case DCCPO_CONFIRM_L: + return dccp_feat_confirm_recv(fn, mandatory, opt, feat, + val, len, server); + } + break; + /* + * Support for exchanging NN options on an established connection + * This is currently restricted to Ack Ratio (RFC 4341, 6.1.2) + */ + case DCCP_OPEN: + case DCCP_PARTOPEN: + return dccp_feat_handle_nn_established(sk, mandatory, opt, feat, + val, len); } - return rc; + return 0; /* ignore FN options in all other states */ } -int dccp_feat_init(struct dccp_minisock *dmsk) +/** + * dccp_feat_init - Seed feature negotiation with host-specific defaults + * This initialises global defaults, depending on the value of the sysctls. + * These can later be overridden by registering changes via setsockopt calls. + * The last link in the chain is finalise_settings, to make sure that between + * here and the start of actual feature negotiation no inconsistencies enter. + * + * All features not appearing below use either defaults or are otherwise + * later adjusted through dccp_feat_finalise_settings(). + */ +int dccp_feat_init(struct sock *sk) { + struct list_head *fn = &dccp_sk(sk)->dccps_featneg; + u8 on = 1, off = 0; int rc; + struct { + u8 *val; + u8 len; + } tx, rx; + + /* Non-negotiable (NN) features */ + rc = __feat_register_nn(fn, DCCPF_SEQUENCE_WINDOW, 0, + sysctl_dccp_sequence_window); + if (rc) + return rc; - INIT_LIST_HEAD(&dmsk->dccpms_pending); - INIT_LIST_HEAD(&dmsk->dccpms_conf); + /* Server-priority (SP) features */ + + /* Advertise that short seqnos are not supported (7.6.1) */ + rc = __feat_register_sp(fn, DCCPF_SHORT_SEQNOS, true, true, &off, 1); + if (rc) + return rc; - /* CCID L */ - rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID, - &dmsk->dccpms_tx_ccid, 1); + /* RFC 4340 12.1: "If a DCCP is not ECN capable, ..." */ + rc = __feat_register_sp(fn, DCCPF_ECN_INCAPABLE, true, true, &on, 1); if (rc) - goto out; + return rc; + + /* + * We advertise the available list of CCIDs and reorder according to + * preferences, to avoid failure resulting from negotiating different + * singleton values (which always leads to failure). + * These settings can still (later) be overridden via sockopts. + */ + if (ccid_get_builtin_ccids(&tx.val, &tx.len) || + ccid_get_builtin_ccids(&rx.val, &rx.len)) + return -ENOBUFS; + + /* Pre-load all CCID modules that are going to be advertised */ + rc = -EUNATCH; + if (ccid_request_modules(tx.val, tx.len)) + goto free_ccid_lists; + + if (!dccp_feat_prefer(sysctl_dccp_tx_ccid, tx.val, tx.len) || + !dccp_feat_prefer(sysctl_dccp_rx_ccid, rx.val, rx.len)) + goto free_ccid_lists; - /* CCID R */ - rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_R, DCCPF_CCID, - &dmsk->dccpms_rx_ccid, 1); + rc = __feat_register_sp(fn, DCCPF_CCID, true, false, tx.val, tx.len); if (rc) - goto out; + goto free_ccid_lists; - /* Ack ratio */ - rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO, - &dmsk->dccpms_ack_ratio, 1); -out: + rc = __feat_register_sp(fn, DCCPF_CCID, false, false, rx.val, rx.len); + +free_ccid_lists: + kfree(tx.val); + kfree(rx.val); return rc; } -EXPORT_SYMBOL_GPL(dccp_feat_init); - -#ifdef CONFIG_IP_DCCP_DEBUG -const char *dccp_feat_typename(const u8 type) +int dccp_feat_activate_values(struct sock *sk, struct list_head *fn_list) { - switch(type) { - case DCCPO_CHANGE_L: return("ChangeL"); - case DCCPO_CONFIRM_L: return("ConfirmL"); - case DCCPO_CHANGE_R: return("ChangeR"); - case DCCPO_CONFIRM_R: return("ConfirmR"); - /* the following case must not appear in feature negotation */ - default: dccp_pr_debug("unknown type %d [BUG!]\n", type); + struct dccp_sock *dp = dccp_sk(sk); + struct dccp_feat_entry *cur, *next; + int idx; + dccp_feat_val *fvals[DCCP_FEAT_SUPPORTED_MAX][2] = { + [0 ... DCCP_FEAT_SUPPORTED_MAX-1] = { NULL, NULL } + }; + + list_for_each_entry(cur, fn_list, node) { + /* + * An empty Confirm means that either an unknown feature type + * or an invalid value was present. In the first case there is + * nothing to activate, in the other the default value is used. + */ + if (cur->empty_confirm) + continue; + + idx = dccp_feat_index(cur->feat_num); + if (idx < 0) { + DCCP_BUG("Unknown feature %u", cur->feat_num); + goto activation_failed; + } + if (cur->state != FEAT_STABLE) { + DCCP_CRIT("Negotiation of %s %s failed in state %s", + cur->is_local ? "local" : "remote", + dccp_feat_fname(cur->feat_num), + dccp_feat_sname[cur->state]); + goto activation_failed; + } + fvals[idx][cur->is_local] = &cur->val; } - return NULL; -} -EXPORT_SYMBOL_GPL(dccp_feat_typename); + /* + * Activate in decreasing order of index, so that the CCIDs are always + * activated as the last feature. This avoids the case where a CCID + * relies on the initialisation of one or more features that it depends + * on (e.g. Send NDP Count, Send Ack Vector, and Ack Ratio features). + */ + for (idx = DCCP_FEAT_SUPPORTED_MAX; --idx >= 0;) + if (__dccp_feat_activate(sk, idx, 0, fvals[idx][0]) || + __dccp_feat_activate(sk, idx, 1, fvals[idx][1])) { + DCCP_CRIT("Could not activate %d", idx); + goto activation_failed; + } -const char *dccp_feat_name(const u8 feat) -{ - static const char *feature_names[] = { - [DCCPF_RESERVED] = "Reserved", - [DCCPF_CCID] = "CCID", - [DCCPF_SHORT_SEQNOS] = "Allow Short Seqnos", - [DCCPF_SEQUENCE_WINDOW] = "Sequence Window", - [DCCPF_ECN_INCAPABLE] = "ECN Incapable", - [DCCPF_ACK_RATIO] = "Ack Ratio", - [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector", - [DCCPF_SEND_NDP_COUNT] = "Send NDP Count", - [DCCPF_MIN_CSUM_COVER] = "Min. Csum Coverage", - [DCCPF_DATA_CHECKSUM] = "Send Data Checksum", - }; - if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC) - return feature_names[DCCPF_RESERVED]; + /* Clean up Change options which have been confirmed already */ + list_for_each_entry_safe(cur, next, fn_list, node) + if (!cur->needs_confirm) + dccp_feat_list_pop(cur); - if (feat >= DCCPF_MIN_CCID_SPECIFIC) - return "CCID-specific"; + dccp_pr_debug("Activation OK\n"); + return 0; - return feature_names[feat]; +activation_failed: + /* + * We clean up everything that may have been allocated, since + * it is difficult to track at which stage negotiation failed. + * This is ok, since all allocation functions below are robust + * against NULL arguments. + */ + ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk); + ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk); + dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL; + dccp_ackvec_free(dp->dccps_hc_rx_ackvec); + dp->dccps_hc_rx_ackvec = NULL; + return -1; } - -EXPORT_SYMBOL_GPL(dccp_feat_name); -#endif /* CONFIG_IP_DCCP_DEBUG */ diff --git a/net/dccp/feat.h b/net/dccp/feat.h index e272222c7ace..2217066e22d7 100644 --- a/net/dccp/feat.h +++ b/net/dccp/feat.h @@ -3,38 +3,134 @@ /* * net/dccp/feat.h * - * An implementation of the DCCP protocol + * Feature negotiation for the DCCP protocol (RFC 4340, section 6) + * Copyright (c) 2008 Gerrit Renker <gerrit@erg.abdn.ac.uk> * Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk> * - * This program is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. */ - #include <linux/types.h> #include "dccp.h" -#ifdef CONFIG_IP_DCCP_DEBUG -extern const char *dccp_feat_typename(const u8 type); -extern const char *dccp_feat_name(const u8 feat); +/* + * Known limit values + */ +/* Ack Ratio takes 2-byte integer values (11.3) */ +#define DCCPF_ACK_RATIO_MAX 0xFFFF +/* Wmin=32 and Wmax=2^46-1 from 7.5.2 */ +#define DCCPF_SEQ_WMIN 32 +#define DCCPF_SEQ_WMAX 0x3FFFFFFFFFFFull +/* Maximum number of SP values that fit in a single (Confirm) option */ +#define DCCP_FEAT_MAX_SP_VALS (DCCP_SINGLE_OPT_MAXLEN - 2) + +enum dccp_feat_type { + FEAT_AT_RX = 1, /* located at RX side of half-connection */ + FEAT_AT_TX = 2, /* located at TX side of half-connection */ + FEAT_SP = 4, /* server-priority reconciliation (6.3.1) */ + FEAT_NN = 8, /* non-negotiable reconciliation (6.3.2) */ + FEAT_UNKNOWN = 0xFF /* not understood or invalid feature */ +}; + +enum dccp_feat_state { + FEAT_DEFAULT = 0, /* using default values from 6.4 */ + FEAT_INITIALISING, /* feature is being initialised */ + FEAT_CHANGING, /* Change sent but not confirmed yet */ + FEAT_UNSTABLE, /* local modification in state CHANGING */ + FEAT_STABLE /* both ends (think they) agree */ +}; -static inline void dccp_feat_debug(const u8 type, const u8 feat, const u8 val) +/** + * dccp_feat_val - Container for SP or NN feature values + * @nn: single NN value + * @sp.vec: single SP value plus optional preference list + * @sp.len: length of @sp.vec in bytes + */ +typedef union { + u64 nn; + struct { + u8 *vec; + u8 len; + } sp; +} dccp_feat_val; + +/** + * struct feat_entry - Data structure to perform feature negotiation + * @feat_num: one of %dccp_feature_numbers + * @val: feature's current value (SP features may have preference list) + * @state: feature's current state + * @needs_mandatory: whether Mandatory options should be sent + * @needs_confirm: whether to send a Confirm instead of a Change + * @empty_confirm: whether to send an empty Confirm (depends on @needs_confirm) + * @is_local: feature location (1) or feature-remote (0) + * @node: list pointers, entries arranged in FIFO order + */ +struct dccp_feat_entry { + u8 feat_num; + dccp_feat_val val; + enum dccp_feat_state state:8; + bool needs_mandatory:1, + needs_confirm:1, + empty_confirm:1, + is_local:1; + + struct list_head node; +}; + +static inline u8 dccp_feat_genopt(struct dccp_feat_entry *entry) { - dccp_pr_debug("%s(%s (%d), %d)\n", dccp_feat_typename(type), - dccp_feat_name(feat), feat, val); + if (entry->needs_confirm) + return entry->is_local ? DCCPO_CONFIRM_L : DCCPO_CONFIRM_R; + return entry->is_local ? DCCPO_CHANGE_L : DCCPO_CHANGE_R; } -#else -#define dccp_feat_debug(type, feat, val) -#endif /* CONFIG_IP_DCCP_DEBUG */ - -extern int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature, - u8 *val, u8 len, gfp_t gfp); -extern int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, - u8 *val, u8 len); -extern int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, - u8 *val, u8 len); -extern void dccp_feat_clean(struct dccp_minisock *dmsk); -extern int dccp_feat_clone(struct sock *oldsk, struct sock *newsk); -extern int dccp_feat_init(struct dccp_minisock *dmsk); +/** + * struct ccid_dependency - Track changes resulting from choosing a CCID + * @dependent_feat: one of %dccp_feature_numbers + * @is_local: local (1) or remote (0) @dependent_feat + * @is_mandatory: whether presence of @dependent_feat is mission-critical or not + * @val: corresponding default value for @dependent_feat (u8 is sufficient here) + */ +struct ccid_dependency { + u8 dependent_feat; + bool is_local:1, + is_mandatory:1; + u8 val; +}; + +/* + * Sysctls to seed defaults for feature negotiation + */ +extern unsigned long sysctl_dccp_sequence_window; +extern int sysctl_dccp_rx_ccid; +extern int sysctl_dccp_tx_ccid; + +extern int dccp_feat_init(struct sock *sk); +extern void dccp_feat_initialise_sysctls(void); +extern int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local, + u8 const *list, u8 len); +extern int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val); +extern int dccp_feat_parse_options(struct sock *, struct dccp_request_sock *, + u8 mand, u8 opt, u8 feat, u8 *val, u8 len); +extern int dccp_feat_clone_list(struct list_head const *, struct list_head *); + +/* + * Encoding variable-length options and their maximum length. + * + * This affects NN options (SP options are all u8) and other variable-length + * options (see table 3 in RFC 4340). The limit is currently given the Sequence + * Window NN value (sec. 7.5.2) and the NDP count (sec. 7.7) option, all other + * options consume less than 6 bytes (timestamps are 4 bytes). + * When updating this constant (e.g. due to new internet drafts / RFCs), make + * sure that you also update all code which refers to it. + */ +#define DCCP_OPTVAL_MAXLEN 6 + +extern void dccp_encode_value_var(const u64 value, u8 *to, const u8 len); +extern u64 dccp_decode_value_var(const u8 *bf, const u8 len); + +extern int dccp_insert_option_mandatory(struct sk_buff *skb); +extern int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat, + u8 *val, u8 len, bool repeat_first); #endif /* _DCCP_FEAT_H */ diff --git a/net/dccp/input.c b/net/dccp/input.c index 779d0ed9ae94..df0e6714aa11 100644 --- a/net/dccp/input.c +++ b/net/dccp/input.c @@ -159,13 +159,15 @@ static void dccp_rcv_reset(struct sock *sk, struct sk_buff *skb) dccp_time_wait(sk, DCCP_TIME_WAIT, 0); } -static void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb) +static void dccp_handle_ackvec_processing(struct sock *sk, struct sk_buff *skb) { - struct dccp_sock *dp = dccp_sk(sk); + struct dccp_ackvec *av = dccp_sk(sk)->dccps_hc_rx_ackvec; - if (dccp_msk(sk)->dccpms_send_ack_vector) - dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk, - DCCP_SKB_CB(skb)->dccpd_ack_seq); + if (av == NULL) + return; + if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) + dccp_ackvec_clear_state(av, DCCP_SKB_CB(skb)->dccpd_ack_seq); + dccp_ackvec_input(av, skb); } static void dccp_deliver_input_to_ccids(struct sock *sk, struct sk_buff *skb) @@ -364,22 +366,13 @@ discard: int dccp_rcv_established(struct sock *sk, struct sk_buff *skb, const struct dccp_hdr *dh, const unsigned len) { - struct dccp_sock *dp = dccp_sk(sk); - if (dccp_check_seqno(sk, skb)) goto discard; if (dccp_parse_options(sk, NULL, skb)) return 1; - if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) - dccp_event_ack_recv(sk, skb); - - if (dccp_msk(sk)->dccpms_send_ack_vector && - dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, - DCCP_SKB_CB(skb)->dccpd_seq, - DCCP_ACKVEC_STATE_RECEIVED)) - goto discard; + dccp_handle_ackvec_processing(sk, skb); dccp_deliver_input_to_ccids(sk, skb); return __dccp_rcv_established(sk, skb, dh, len); @@ -421,40 +414,33 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk, goto out_invalid_packet; } + /* + * If option processing (Step 8) failed, return 1 here so that + * dccp_v4_do_rcv() sends a Reset. The Reset code depends on + * the option type and is set in dccp_parse_options(). + */ if (dccp_parse_options(sk, NULL, skb)) - goto out_invalid_packet; + return 1; /* Obtain usec RTT sample from SYN exchange (used by CCID 3) */ if (likely(dp->dccps_options_received.dccpor_timestamp_echo)) dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp - dp->dccps_options_received.dccpor_timestamp_echo)); - if (dccp_msk(sk)->dccpms_send_ack_vector && - dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, - DCCP_SKB_CB(skb)->dccpd_seq, - DCCP_ACKVEC_STATE_RECEIVED)) - goto out_invalid_packet; /* FIXME: change error code */ - /* Stop the REQUEST timer */ inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); WARN_ON(sk->sk_send_head == NULL); kfree_skb(sk->sk_send_head); sk->sk_send_head = NULL; - dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq; - dccp_update_gsr(sk, dp->dccps_isr); /* - * SWL and AWL are initially adjusted so that they are not less than - * the initial Sequence Numbers received and sent, respectively: - * SWL := max(GSR + 1 - floor(W/4), ISR), - * AWL := max(GSS - W' + 1, ISS). - * These adjustments MUST be applied only at the beginning of the - * connection. - * - * AWL was adjusted in dccp_v4_connect -acme + * Set ISR, GSR from packet. ISS was set in dccp_v{4,6}_connect + * and GSS in dccp_transmit_skb(). Setting AWL/AWH and SWL/SWH + * is done as part of activating the feature values below, since + * these settings depend on the local/remote Sequence Window + * features, which were undefined or not confirmed until now. */ - dccp_set_seqno(&dp->dccps_swl, - max48(dp->dccps_swl, dp->dccps_isr)); + dp->dccps_gsr = dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq; dccp_sync_mss(sk, icsk->icsk_pmtu_cookie); @@ -475,6 +461,15 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk, */ dccp_set_state(sk, DCCP_PARTOPEN); + /* + * If feature negotiation was successful, activate features now; + * an activation failure means that this host could not activate + * one ore more features (e.g. insufficient memory), which would + * leave at least one feature in an undefined state. + */ + if (dccp_feat_activate_values(sk, &dp->dccps_featneg)) + goto unable_to_proceed; + /* Make sure socket is routed, for correct metrics. */ icsk->icsk_af_ops->rebuild_header(sk); @@ -509,6 +504,16 @@ out_invalid_packet: /* dccp_v4_do_rcv will send a reset */ DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; return 1; + +unable_to_proceed: + DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_ABORTED; + /* + * We mark this socket as no longer usable, so that the loop in + * dccp_sendmsg() terminates and the application gets notified. + */ + dccp_set_state(sk, DCCP_CLOSED); + sk->sk_err = ECOMM; + return 1; } static int dccp_rcv_respond_partopen_state_process(struct sock *sk, @@ -590,8 +595,6 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, if (inet_csk(sk)->icsk_af_ops->conn_request(sk, skb) < 0) return 1; - - /* FIXME: do congestion control initialization */ goto discard; } if (dh->dccph_type == DCCP_PKT_RESET) @@ -600,30 +603,36 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, /* Caller (dccp_v4_do_rcv) will send Reset */ dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; return 1; + } else if (sk->sk_state == DCCP_CLOSED) { + dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; + return 1; } - if (sk->sk_state != DCCP_REQUESTING) { - if (dccp_check_seqno(sk, skb)) - goto discard; - - /* - * Step 8: Process options and mark acknowledgeable - */ - if (dccp_parse_options(sk, NULL, skb)) - return 1; - - if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) - dccp_event_ack_recv(sk, skb); - - if (dccp_msk(sk)->dccpms_send_ack_vector && - dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, - DCCP_SKB_CB(skb)->dccpd_seq, - DCCP_ACKVEC_STATE_RECEIVED)) - goto discard; + /* Step 6: Check sequence numbers (omitted in LISTEN/REQUEST state) */ + if (sk->sk_state != DCCP_REQUESTING && dccp_check_seqno(sk, skb)) + goto discard; - dccp_deliver_input_to_ccids(sk, skb); + /* + * Step 7: Check for unexpected packet types + * If (S.is_server and P.type == Response) + * or (S.is_client and P.type == Request) + * or (S.state == RESPOND and P.type == Data), + * Send Sync packet acknowledging P.seqno + * Drop packet and return + */ + if ((dp->dccps_role != DCCP_ROLE_CLIENT && + dh->dccph_type == DCCP_PKT_RESPONSE) || + (dp->dccps_role == DCCP_ROLE_CLIENT && + dh->dccph_type == DCCP_PKT_REQUEST) || + (sk->sk_state == DCCP_RESPOND && dh->dccph_type == DCCP_PKT_DATA)) { + dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC); + goto discard; } + /* Step 8: Process options */ + if (dccp_parse_options(sk, NULL, skb)) + return 1; + /* * Step 9: Process Reset * If P.type == Reset, @@ -631,44 +640,22 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, * S.state := TIMEWAIT * Set TIMEWAIT timer * Drop packet and return - */ + */ if (dh->dccph_type == DCCP_PKT_RESET) { dccp_rcv_reset(sk, skb); return 0; - /* - * Step 7: Check for unexpected packet types - * If (S.is_server and P.type == Response) - * or (S.is_client and P.type == Request) - * or (S.state == RESPOND and P.type == Data), - * Send Sync packet acknowledging P.seqno - * Drop packet and return - */ - } else if ((dp->dccps_role != DCCP_ROLE_CLIENT && - dh->dccph_type == DCCP_PKT_RESPONSE) || - (dp->dccps_role == DCCP_ROLE_CLIENT && - dh->dccph_type == DCCP_PKT_REQUEST) || - (sk->sk_state == DCCP_RESPOND && - dh->dccph_type == DCCP_PKT_DATA)) { - dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC); - goto discard; - } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) { + } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) { /* Step 13 */ if (dccp_rcv_closereq(sk, skb)) return 0; goto discard; - } else if (dh->dccph_type == DCCP_PKT_CLOSE) { + } else if (dh->dccph_type == DCCP_PKT_CLOSE) { /* Step 14 */ if (dccp_rcv_close(sk, skb)) return 0; goto discard; } switch (sk->sk_state) { - case DCCP_CLOSED: - dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; - return 1; - case DCCP_REQUESTING: - /* FIXME: do congestion control initialization */ - queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len); if (queued >= 0) return queued; @@ -676,8 +663,12 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, __kfree_skb(skb); return 0; - case DCCP_RESPOND: case DCCP_PARTOPEN: + /* Step 8: if using Ack Vectors, mark packet acknowledgeable */ + dccp_handle_ackvec_processing(sk, skb); + dccp_deliver_input_to_ccids(sk, skb); + /* fall through */ + case DCCP_RESPOND: queued = dccp_rcv_respond_partopen_state_process(sk, skb, dh, len); break; @@ -716,16 +707,7 @@ u32 dccp_sample_rtt(struct sock *sk, long delta) /* dccpor_elapsed_time is either zeroed out or set and > 0 */ delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10; - if (unlikely(delta <= 0)) { - DCCP_WARN("unusable RTT sample %ld, using min\n", delta); - return DCCP_SANE_RTT_MIN; - } - if (unlikely(delta > DCCP_SANE_RTT_MAX)) { - DCCP_WARN("RTT sample %ld too large, using max\n", delta); - return DCCP_SANE_RTT_MAX; - } - - return delta; + return dccp_sane_rtt(delta); } EXPORT_SYMBOL_GPL(dccp_sample_rtt); diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index 882c5c4de69e..b623f6b25482 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -545,6 +545,7 @@ out: static void dccp_v4_reqsk_destructor(struct request_sock *req) { + dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg); kfree(inet_rsk(req)->opt); } @@ -595,7 +596,8 @@ int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb) if (req == NULL) goto drop; - dccp_reqsk_init(req, skb); + if (dccp_reqsk_init(req, dccp_sk(sk), skb)) + goto drop_and_free; dreq = dccp_rsk(req); if (dccp_parse_options(sk, dreq, skb)) diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c index 5e1ee0da2c40..ad6212e00435 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -302,6 +302,7 @@ done: static void dccp_v6_reqsk_destructor(struct request_sock *req) { + dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg); if (inet6_rsk(req)->pktopts != NULL) kfree_skb(inet6_rsk(req)->pktopts); } @@ -424,7 +425,8 @@ static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb) if (req == NULL) goto drop; - dccp_reqsk_init(req, skb); + if (dccp_reqsk_init(req, dccp_sk(sk), skb)) + goto drop_and_free; dreq = dccp_rsk(req); if (dccp_parse_options(sk, dreq, skb)) diff --git a/net/dccp/minisocks.c b/net/dccp/minisocks.c index b2804e2d1b8c..f4d9c8f60ede 100644 --- a/net/dccp/minisocks.c +++ b/net/dccp/minisocks.c @@ -42,16 +42,6 @@ struct inet_timewait_death_row dccp_death_row = { EXPORT_SYMBOL_GPL(dccp_death_row); -void dccp_minisock_init(struct dccp_minisock *dmsk) -{ - dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window; - dmsk->dccpms_rx_ccid = sysctl_dccp_feat_rx_ccid; - dmsk->dccpms_tx_ccid = sysctl_dccp_feat_tx_ccid; - dmsk->dccpms_ack_ratio = sysctl_dccp_feat_ack_ratio; - dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector; - dmsk->dccpms_send_ndp_count = sysctl_dccp_feat_send_ndp_count; -} - void dccp_time_wait(struct sock *sk, int state, int timeo) { struct inet_timewait_sock *tw = NULL; @@ -112,10 +102,9 @@ struct sock *dccp_create_openreq_child(struct sock *sk, struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC); if (newsk != NULL) { - const struct dccp_request_sock *dreq = dccp_rsk(req); + struct dccp_request_sock *dreq = dccp_rsk(req); struct inet_connection_sock *newicsk = inet_csk(newsk); struct dccp_sock *newdp = dccp_sk(newsk); - struct dccp_minisock *newdmsk = dccp_msk(newsk); newdp->dccps_role = DCCP_ROLE_SERVER; newdp->dccps_hc_rx_ackvec = NULL; @@ -125,65 +114,32 @@ struct sock *dccp_create_openreq_child(struct sock *sk, newdp->dccps_timestamp_time = dreq->dreq_timestamp_time; newicsk->icsk_rto = DCCP_TIMEOUT_INIT; - if (dccp_feat_clone(sk, newsk)) - goto out_free; - - if (newdmsk->dccpms_send_ack_vector) { - newdp->dccps_hc_rx_ackvec = - dccp_ackvec_alloc(GFP_ATOMIC); - if (unlikely(newdp->dccps_hc_rx_ackvec == NULL)) - goto out_free; - } - - newdp->dccps_hc_rx_ccid = - ccid_hc_rx_new(newdmsk->dccpms_rx_ccid, - newsk, GFP_ATOMIC); - newdp->dccps_hc_tx_ccid = - ccid_hc_tx_new(newdmsk->dccpms_tx_ccid, - newsk, GFP_ATOMIC); - if (unlikely(newdp->dccps_hc_rx_ccid == NULL || - newdp->dccps_hc_tx_ccid == NULL)) { - dccp_ackvec_free(newdp->dccps_hc_rx_ackvec); - ccid_hc_rx_delete(newdp->dccps_hc_rx_ccid, newsk); - ccid_hc_tx_delete(newdp->dccps_hc_tx_ccid, newsk); -out_free: - /* It is still raw copy of parent, so invalidate - * destructor and make plain sk_free() */ - newsk->sk_destruct = NULL; - sk_free(newsk); - return NULL; - } - + INIT_LIST_HEAD(&newdp->dccps_featneg); /* * Step 3: Process LISTEN state * * Choose S.ISS (initial seqno) or set from Init Cookies * Initialize S.GAR := S.ISS - * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies + * Set S.ISR, S.GSR from packet (or Init Cookies) + * + * Setting AWL/AWH and SWL/SWH happens as part of the feature + * activation below, as these windows all depend on the local + * and remote Sequence Window feature values (7.5.2). */ - - /* See dccp_v4_conn_request */ - newdmsk->dccpms_sequence_window = req->rcv_wnd; - - newdp->dccps_gar = newdp->dccps_iss = dreq->dreq_iss; - dccp_update_gss(newsk, dreq->dreq_iss); - - newdp->dccps_isr = dreq->dreq_isr; - dccp_update_gsr(newsk, dreq->dreq_isr); + newdp->dccps_gss = newdp->dccps_iss = dreq->dreq_iss; + newdp->dccps_gar = newdp->dccps_iss; + newdp->dccps_gsr = newdp->dccps_isr = dreq->dreq_isr; /* - * SWL and AWL are initially adjusted so that they are not less than - * the initial Sequence Numbers received and sent, respectively: - * SWL := max(GSR + 1 - floor(W/4), ISR), - * AWL := max(GSS - W' + 1, ISS). - * These adjustments MUST be applied only at the beginning of the - * connection. + * Activate features: initialise CCIDs, sequence windows etc. */ - dccp_set_seqno(&newdp->dccps_swl, - max48(newdp->dccps_swl, newdp->dccps_isr)); - dccp_set_seqno(&newdp->dccps_awl, - max48(newdp->dccps_awl, newdp->dccps_iss)); - + if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) { + /* It is still raw copy of parent, so invalidate + * destructor and make plain sk_free() */ + newsk->sk_destruct = NULL; + sk_free(newsk); + return NULL; + } dccp_init_xmit_timers(newsk); DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS); @@ -304,14 +260,17 @@ void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack); -void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb) +int dccp_reqsk_init(struct request_sock *req, + struct dccp_sock const *dp, struct sk_buff const *skb) { struct dccp_request_sock *dreq = dccp_rsk(req); inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport; inet_rsk(req)->acked = 0; - req->rcv_wnd = sysctl_dccp_feat_sequence_window; dreq->dreq_timestamp_echo = 0; + + /* inherit feature negotiation options from listening socket */ + return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg); } EXPORT_SYMBOL_GPL(dccp_reqsk_init); diff --git a/net/dccp/options.c b/net/dccp/options.c index 0809b63cb055..e5a32979d7d7 100644 --- a/net/dccp/options.c +++ b/net/dccp/options.c @@ -23,23 +23,20 @@ #include "dccp.h" #include "feat.h" -int sysctl_dccp_feat_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW; -int sysctl_dccp_feat_rx_ccid = DCCPF_INITIAL_CCID; -int sysctl_dccp_feat_tx_ccid = DCCPF_INITIAL_CCID; -int sysctl_dccp_feat_ack_ratio = DCCPF_INITIAL_ACK_RATIO; -int sysctl_dccp_feat_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR; -int sysctl_dccp_feat_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT; - -static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len) +u64 dccp_decode_value_var(const u8 *bf, const u8 len) { - u32 value = 0; + u64 value = 0; + if (len >= DCCP_OPTVAL_MAXLEN) + value += ((u64)*bf++) << 40; + if (len > 4) + value += ((u64)*bf++) << 32; if (len > 3) - value += *bf++ << 24; + value += ((u64)*bf++) << 24; if (len > 2) - value += *bf++ << 16; + value += ((u64)*bf++) << 16; if (len > 1) - value += *bf++ << 8; + value += ((u64)*bf++) << 8; if (len > 0) value += *bf; @@ -57,7 +54,6 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq, struct dccp_sock *dp = dccp_sk(sk); const struct dccp_hdr *dh = dccp_hdr(skb); const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type; - u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); unsigned char *opt_ptr = options; const unsigned char *opt_end = (unsigned char *)dh + @@ -99,18 +95,11 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq, } /* - * CCID-Specific Options (from RFC 4340, sec. 10.3): - * - * Option numbers 128 through 191 are for options sent from the - * HC-Sender to the HC-Receiver; option numbers 192 through 255 - * are for options sent from the HC-Receiver to the HC-Sender. - * * CCID-specific options are ignored during connection setup, as * negotiation may still be in progress (see RFC 4340, 10.3). * The same applies to Ack Vectors, as these depend on the CCID. - * */ - if (dreq != NULL && (opt >= 128 || + if (dreq != NULL && (opt >= DCCPO_MIN_RX_CCID_SPECIFIC || opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1)) goto ignore_option; @@ -131,43 +120,13 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq, dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk), (unsigned long long)opt_recv->dccpor_ndp); break; - case DCCPO_CHANGE_L: - /* fall through */ - case DCCPO_CHANGE_R: - if (pkt_type == DCCP_PKT_DATA) + case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R: + if (pkt_type == DCCP_PKT_DATA) /* RFC 4340, 6 */ break; - if (len < 2) - goto out_invalid_option; - rc = dccp_feat_change_recv(sk, opt, *value, value + 1, - len - 1); - /* - * When there is a change error, change_recv is - * responsible for dealing with it. i.e. reply with an - * empty confirm. - * If the change was mandatory, then we need to die. - */ - if (rc && mandatory) - goto out_invalid_option; - break; - case DCCPO_CONFIRM_L: - /* fall through */ - case DCCPO_CONFIRM_R: - if (pkt_type == DCCP_PKT_DATA) - break; - if (len < 2) /* FIXME this disallows empty confirm */ - goto out_invalid_option; - if (dccp_feat_confirm_recv(sk, opt, *value, - value + 1, len - 1)) - goto out_invalid_option; - break; - case DCCPO_ACK_VECTOR_0: - case DCCPO_ACK_VECTOR_1: - if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */ - break; - - if (dccp_msk(sk)->dccpms_send_ack_vector && - dccp_ackvec_parse(sk, skb, &ackno, opt, value, len)) - goto out_invalid_option; + rc = dccp_feat_parse_options(sk, dreq, mandatory, opt, + *value, value + 1, len - 1); + if (rc) + goto out_featneg_failed; break; case DCCPO_TIMESTAMP: if (len != 4) @@ -195,6 +154,8 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq, dccp_role(sk), ntohl(opt_val), (unsigned long long) DCCP_SKB_CB(skb)->dccpd_ack_seq); + /* schedule an Ack in case this sender is quiescent */ + inet_csk_schedule_ack(sk); break; case DCCPO_TIMESTAMP_ECHO: if (len != 4 && len != 6 && len != 8) @@ -251,23 +212,25 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq, dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n", dccp_role(sk), elapsed_time); break; - case 128 ... 191: { - const u16 idx = value - options; - + case DCCPO_MIN_RX_CCID_SPECIFIC ... DCCPO_MAX_RX_CCID_SPECIFIC: if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk, - opt, len, idx, - value) != 0) + pkt_type, opt, value, len)) goto out_invalid_option; - } break; - case 192 ... 255: { - const u16 idx = value - options; - + case DCCPO_ACK_VECTOR_0: + case DCCPO_ACK_VECTOR_1: + if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */ + break; + /* + * Ack vectors are processed by the TX CCID if it is + * interested. The RX CCID need not parse Ack Vectors, + * since it is only interested in clearing old state. + * Fall through. + */ + case DCCPO_MIN_TX_CCID_SPECIFIC ... DCCPO_MAX_TX_CCID_SPECIFIC: if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk, - opt, len, idx, - value) != 0) + pkt_type, opt, value, len)) goto out_invalid_option; - } break; default: DCCP_CRIT("DCCP(%p): option %d(len=%d) not " @@ -289,8 +252,10 @@ out_nonsensical_length: out_invalid_option: DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT); - DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR; - DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len); + rc = DCCP_RESET_CODE_OPTION_ERROR; +out_featneg_failed: + DCCP_WARN("DCCP(%p): Option %d (len=%d) error=%u\n", sk, opt, len, rc); + DCCP_SKB_CB(skb)->dccpd_reset_code = rc; DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt; DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0; DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0; @@ -299,9 +264,12 @@ out_invalid_option: EXPORT_SYMBOL_GPL(dccp_parse_options); -static void dccp_encode_value_var(const u32 value, unsigned char *to, - const unsigned int len) +void dccp_encode_value_var(const u64 value, u8 *to, const u8 len) { + if (len >= DCCP_OPTVAL_MAXLEN) + *to++ = (value & 0xFF0000000000ull) >> 40; + if (len > 4) + *to++ = (value & 0xFF00000000ull) >> 32; if (len > 3) *to++ = (value & 0xFF000000) >> 24; if (len > 2) @@ -461,92 +429,140 @@ static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp, return 0; } -static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat, - u8 *val, u8 len) +static int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb) { - u8 *to; + struct dccp_sock *dp = dccp_sk(sk); + struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec; + struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); + const u16 buflen = dccp_ackvec_buflen(av); + /* Figure out how many options do we need to represent the ackvec */ + const u8 nr_opts = DIV_ROUND_UP(buflen, DCCP_SINGLE_OPT_MAXLEN); + u16 len = buflen + 2 * nr_opts; + u8 i, nonce = 0; + const unsigned char *tail, *from; + unsigned char *to; - if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) { - DCCP_WARN("packet too small for feature %d option!\n", feat); + if (dcb->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) { + DCCP_WARN("Lacking space for %u bytes on %s packet\n", len, + dccp_packet_name(dcb->dccpd_type)); return -1; } + /* + * Since Ack Vectors are variable-length, we can not always predict + * their size. To catch exception cases where the space is running out + * on the skb, a separate Sync is scheduled to carry the Ack Vector. + */ + if (len > DCCPAV_MIN_OPTLEN && + len + dcb->dccpd_opt_len + skb->len > dp->dccps_mss_cache) { + DCCP_WARN("No space left for Ack Vector (%u) on skb (%u+%u), " + "MPS=%u ==> reduce payload size?\n", len, skb->len, + dcb->dccpd_opt_len, dp->dccps_mss_cache); + dp->dccps_sync_scheduled = 1; + return 0; + } + dcb->dccpd_opt_len += len; - DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3; + to = skb_push(skb, len); + len = buflen; + from = av->av_buf + av->av_buf_head; + tail = av->av_buf + DCCPAV_MAX_ACKVEC_LEN; - to = skb_push(skb, len + 3); - *to++ = type; - *to++ = len + 3; - *to++ = feat; + for (i = 0; i < nr_opts; ++i) { + int copylen = len; - if (len) - memcpy(to, val, len); + if (len > DCCP_SINGLE_OPT_MAXLEN) + copylen = DCCP_SINGLE_OPT_MAXLEN; + + /* + * RFC 4340, 12.2: Encode the Nonce Echo for this Ack Vector via + * its type; ack_nonce is the sum of all individual buf_nonce's. + */ + nonce ^= av->av_buf_nonce[i]; + + *to++ = DCCPO_ACK_VECTOR_0 + av->av_buf_nonce[i]; + *to++ = copylen + 2; - dccp_pr_debug("%s(%s (%d), ...), length %d\n", - dccp_feat_typename(type), - dccp_feat_name(feat), feat, len); + /* Check if buf_head wraps */ + if (from + copylen > tail) { + const u16 tailsize = tail - from; + + memcpy(to, from, tailsize); + to += tailsize; + len -= tailsize; + copylen -= tailsize; + from = av->av_buf; + } + + memcpy(to, from, copylen); + from += copylen; + to += copylen; + len -= copylen; + } + /* + * Each sent Ack Vector is recorded in the list, as per A.2 of RFC 4340. + */ + if (dccp_ackvec_update_records(av, dcb->dccpd_seq, nonce)) + return -ENOBUFS; return 0; } -static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb) +/** + * dccp_insert_option_mandatory - Mandatory option (5.8.2) + * Note that since we are using skb_push, this function needs to be called + * _after_ inserting the option it is supposed to influence (stack order). + */ +int dccp_insert_option_mandatory(struct sk_buff *skb) { - struct dccp_sock *dp = dccp_sk(sk); - struct dccp_minisock *dmsk = dccp_msk(sk); - struct dccp_opt_pend *opt, *next; - int change = 0; - - /* confirm any options [NN opts] */ - list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) { - dccp_insert_feat_opt(skb, opt->dccpop_type, - opt->dccpop_feat, opt->dccpop_val, - opt->dccpop_len); - /* fear empty confirms */ - if (opt->dccpop_val) - kfree(opt->dccpop_val); - kfree(opt); - } - INIT_LIST_HEAD(&dmsk->dccpms_conf); - - /* see which features we need to send */ - list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { - /* see if we need to send any confirm */ - if (opt->dccpop_sc) { - dccp_insert_feat_opt(skb, opt->dccpop_type + 1, - opt->dccpop_feat, - opt->dccpop_sc->dccpoc_val, - opt->dccpop_sc->dccpoc_len); - - BUG_ON(!opt->dccpop_sc->dccpoc_val); - kfree(opt->dccpop_sc->dccpoc_val); - kfree(opt->dccpop_sc); - opt->dccpop_sc = NULL; - } + if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN) + return -1; - /* any option not confirmed, re-send it */ - if (!opt->dccpop_conf) { - dccp_insert_feat_opt(skb, opt->dccpop_type, - opt->dccpop_feat, opt->dccpop_val, - opt->dccpop_len); - change++; - } + DCCP_SKB_CB(skb)->dccpd_opt_len++; + *skb_push(skb, 1) = DCCPO_MANDATORY; + return 0; +} + +/** + * dccp_insert_fn_opt - Insert single Feature-Negotiation option into @skb + * @type: %DCCPO_CHANGE_L, %DCCPO_CHANGE_R, %DCCPO_CONFIRM_L, %DCCPO_CONFIRM_R + * @feat: one out of %dccp_feature_numbers + * @val: NN value or SP array (preferred element first) to copy + * @len: true length of @val in bytes (excluding first element repetition) + * @repeat_first: whether to copy the first element of @val twice + * The last argument is used to construct Confirm options, where the preferred + * value and the preference list appear separately (RFC 4340, 6.3.1). Preference + * lists are kept such that the preferred entry is always first, so we only need + * to copy twice, and avoid the overhead of cloning into a bigger array. + */ +int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat, + u8 *val, u8 len, bool repeat_first) +{ + u8 tot_len, *to; + + /* take the `Feature' field and possible repetition into account */ + if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) { + DCCP_WARN("length %u for feature %u too large\n", len, feat); + return -1; } - /* Retransmit timer. - * If this is the master listening sock, we don't set a timer on it. It - * should be fine because if the dude doesn't receive our RESPONSE - * [which will contain the CHANGE] he will send another REQUEST which - * will "retrnasmit" the change. - */ - if (change && dp->dccps_role != DCCP_ROLE_LISTEN) { - dccp_pr_debug("reset feat negotiation timer %p\n", sk); + if (unlikely(val == NULL || len == 0)) + len = repeat_first = 0; + tot_len = 3 + repeat_first + len; - /* XXX don't reset the timer on re-transmissions. I.e. reset it - * only when sending new stuff i guess. Currently the timer - * never backs off because on re-transmission it just resets it! - */ - inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, - inet_csk(sk)->icsk_rto, DCCP_RTO_MAX); + if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) { + DCCP_WARN("packet too small for feature %d option!\n", feat); + return -1; } + DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len; + + to = skb_push(skb, tot_len); + *to++ = type; + *to++ = tot_len; + *to++ = feat; + if (repeat_first) + *to++ = *val; + if (len) + memcpy(to, val, len); return 0; } @@ -565,19 +581,30 @@ static void dccp_insert_option_padding(struct sk_buff *skb) int dccp_insert_options(struct sock *sk, struct sk_buff *skb) { struct dccp_sock *dp = dccp_sk(sk); - struct dccp_minisock *dmsk = dccp_msk(sk); DCCP_SKB_CB(skb)->dccpd_opt_len = 0; - if (dmsk->dccpms_send_ndp_count && - dccp_insert_option_ndp(sk, skb)) + if (dp->dccps_send_ndp_count && dccp_insert_option_ndp(sk, skb)) return -1; - if (!dccp_packet_without_ack(skb)) { - if (dmsk->dccpms_send_ack_vector && - dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) && - dccp_insert_option_ackvec(sk, skb)) + if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) { + + /* Feature Negotiation */ + if (dccp_feat_insert_opts(dp, NULL, skb)) return -1; + + if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) { + /* + * Obtain RTT sample from Request/Response exchange. + * This is currently used in CCID 3 initialisation. + */ + if (dccp_insert_option_timestamp(sk, skb)) + return -1; + + } else if (dccp_ackvec_pending(sk) && + dccp_insert_option_ackvec(sk, skb)) { + return -1; + } } if (dp->dccps_hc_rx_insert_options) { @@ -586,21 +613,6 @@ int dccp_insert_options(struct sock *sk, struct sk_buff *skb) dp->dccps_hc_rx_insert_options = 0; } - /* Feature negotiation */ - /* Data packets can't do feat negotiation */ - if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA && - DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK && - dccp_insert_options_feat(sk, skb)) - return -1; - - /* - * Obtain RTT sample from Request/Response exchange. - * This is currently used in CCID 3 initialisation. - */ - if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST && - dccp_insert_option_timestamp(sk, skb)) - return -1; - if (dp->dccps_timestamp_echo != 0 && dccp_insert_option_timestamp_echo(dp, NULL, skb)) return -1; @@ -613,6 +625,9 @@ int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb) { DCCP_SKB_CB(skb)->dccpd_opt_len = 0; + if (dccp_feat_insert_opts(NULL, dreq, skb)) + return -1; + if (dreq->dreq_timestamp_echo != 0 && dccp_insert_option_timestamp_echo(NULL, dreq, skb)) return -1; diff --git a/net/dccp/output.c b/net/dccp/output.c index d06945c7d3df..2532797a8009 100644 --- a/net/dccp/output.c +++ b/net/dccp/output.c @@ -26,11 +26,13 @@ static inline void dccp_event_ack_sent(struct sock *sk) inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); } -static void dccp_skb_entail(struct sock *sk, struct sk_buff *skb) +/* enqueue @skb on sk_send_head for retransmission, return clone to send now */ +static struct sk_buff *dccp_skb_entail(struct sock *sk, struct sk_buff *skb) { skb_set_owner_w(skb, sk); WARN_ON(sk->sk_send_head); sk->sk_send_head = skb; + return skb_clone(sk->sk_send_head, gfp_any()); } /* @@ -161,21 +163,27 @@ unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu) struct inet_connection_sock *icsk = inet_csk(sk); struct dccp_sock *dp = dccp_sk(sk); u32 ccmps = dccp_determine_ccmps(dp); - int cur_mps = ccmps ? min(pmtu, ccmps) : pmtu; + u32 cur_mps = ccmps ? min(pmtu, ccmps) : pmtu; /* Account for header lengths and IPv4/v6 option overhead */ cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len + sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext)); /* - * FIXME: this should come from the CCID infrastructure, where, say, - * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets - * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED - * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to - * make it a multiple of 4 + * Leave enough headroom for common DCCP header options. + * This only considers options which may appear on DCCP-Data packets, as + * per table 3 in RFC 4340, 5.8. When running out of space for other + * options (eg. Ack Vector which can take up to 255 bytes), it is better + * to schedule a separate Ack. Thus we leave headroom for the following: + * - 1 byte for Slow Receiver (11.6) + * - 6 bytes for Timestamp (13.1) + * - 10 bytes for Timestamp Echo (13.3) + * - 8 bytes for NDP count (7.7, when activated) + * - 6 bytes for Data Checksum (9.3) + * - %DCCPAV_MIN_OPTLEN bytes for Ack Vector size (11.4, when enabled) */ - - cur_mps -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4; + cur_mps -= roundup(1 + 6 + 10 + dp->dccps_send_ndp_count * 8 + 6 + + (dp->dccps_hc_rx_ackvec ? DCCPAV_MIN_OPTLEN : 0), 4); /* And store cached results */ icsk->icsk_pmtu_cookie = pmtu; @@ -200,95 +208,158 @@ void dccp_write_space(struct sock *sk) } /** - * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet + * dccp_wait_for_ccid - Await CCID send permission * @sk: socket to wait for - * @skb: current skb to pass on for waiting - * @delay: sleep timeout in milliseconds (> 0) - * This function is called by default when the socket is closed, and - * when a non-zero linger time is set on the socket. For consistency + * @delay: timeout in jiffies + * This is used by CCIDs which need to delay the send time in process context. */ -static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay) +static int dccp_wait_for_ccid(struct sock *sk, unsigned long delay) { - struct dccp_sock *dp = dccp_sk(sk); DEFINE_WAIT(wait); - unsigned long jiffdelay; - int rc; + long remaining; - do { - dccp_pr_debug("delayed send by %d msec\n", delay); - jiffdelay = msecs_to_jiffies(delay); + prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE); + sk->sk_write_pending++; + release_sock(sk); - prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE); + remaining = schedule_timeout(delay); - sk->sk_write_pending++; - release_sock(sk); - schedule_timeout(jiffdelay); - lock_sock(sk); - sk->sk_write_pending--; + lock_sock(sk); + sk->sk_write_pending--; + finish_wait(sk->sk_sleep, &wait); - if (sk->sk_err) - goto do_error; - if (signal_pending(current)) - goto do_interrupted; + if (signal_pending(current) || sk->sk_err) + return -1; + return remaining; +} - rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); - } while ((delay = rc) > 0); -out: - finish_wait(sk->sk_sleep, &wait); - return rc; - -do_error: - rc = -EPIPE; - goto out; -do_interrupted: - rc = -EINTR; - goto out; +/** + * dccp_xmit_packet - Send data packet under control of CCID + * Transmits next-queued payload and informs CCID to account for the packet. + */ +static void dccp_xmit_packet(struct sock *sk) +{ + int err, len; + struct dccp_sock *dp = dccp_sk(sk); + struct sk_buff *skb = dccp_qpolicy_pop(sk); + + if (unlikely(skb == NULL)) + return; + len = skb->len; + + if (sk->sk_state == DCCP_PARTOPEN) { + const u32 cur_mps = dp->dccps_mss_cache - DCCP_FEATNEG_OVERHEAD; + /* + * See 8.1.5 - Handshake Completion. + * + * For robustness we resend Confirm options until the client has + * entered OPEN. During the initial feature negotiation, the MPS + * is smaller than usual, reduced by the Change/Confirm options. + */ + if (!list_empty(&dp->dccps_featneg) && len > cur_mps) { + DCCP_WARN("Payload too large (%d) for featneg.\n", len); + dccp_send_ack(sk); + dccp_feat_list_purge(&dp->dccps_featneg); + } + + inet_csk_schedule_ack(sk); + inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, + inet_csk(sk)->icsk_rto, + DCCP_RTO_MAX); + DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATAACK; + } else if (dccp_ack_pending(sk)) { + DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATAACK; + } else { + DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATA; + } + + err = dccp_transmit_skb(sk, skb); + if (err) + dccp_pr_debug("transmit_skb() returned err=%d\n", err); + /* + * Register this one as sent even if an error occurred. To the remote + * end a local packet drop is indistinguishable from network loss, i.e. + * any local drop will eventually be reported via receiver feedback. + */ + ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, len); + + /* + * If the CCID needs to transfer additional header options out-of-band + * (e.g. Ack Vectors or feature-negotiation options), it activates this + * flag to schedule a Sync. The Sync will automatically incorporate all + * currently pending header options, thus clearing the backlog. + */ + if (dp->dccps_sync_scheduled) + dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC); } -void dccp_write_xmit(struct sock *sk, int block) +/** + * dccp_flush_write_queue - Drain queue at end of connection + * Since dccp_sendmsg queues packets without waiting for them to be sent, it may + * happen that the TX queue is not empty at the end of a connection. We give the + * HC-sender CCID a grace period of up to @time_budget jiffies. If this function + * returns with a non-empty write queue, it will be purged later. + */ +void dccp_flush_write_queue(struct sock *sk, long *time_budget) { struct dccp_sock *dp = dccp_sk(sk); struct sk_buff *skb; + long delay, rc; + + while (*time_budget > 0 && (skb = skb_peek(&sk->sk_write_queue))) { + rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); - while ((skb = skb_peek(&sk->sk_write_queue))) { - int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); - - if (err > 0) { - if (!block) { - sk_reset_timer(sk, &dp->dccps_xmit_timer, - msecs_to_jiffies(err)+jiffies); - break; - } else - err = dccp_wait_for_ccid(sk, skb, err); - if (err && err != -EINTR) - DCCP_BUG("err=%d after dccp_wait_for_ccid", err); + switch (ccid_packet_dequeue_eval(rc)) { + case CCID_PACKET_WILL_DEQUEUE_LATER: + /* + * If the CCID determines when to send, the next sending + * time is unknown or the CCID may not even send again + * (e.g. remote host crashes or lost Ack packets). + */ + DCCP_WARN("CCID did not manage to send all packets\n"); + return; + case CCID_PACKET_DELAY: + delay = msecs_to_jiffies(rc); + if (delay > *time_budget) + return; + rc = dccp_wait_for_ccid(sk, delay); + if (rc < 0) + return; + *time_budget -= (delay - rc); + /* check again if we can send now */ + break; + case CCID_PACKET_SEND_AT_ONCE: + dccp_xmit_packet(sk); + break; + case CCID_PACKET_ERR: + skb_dequeue(&sk->sk_write_queue); + kfree_skb(skb); + dccp_pr_debug("packet discarded due to err=%ld\n", rc); } + } +} - skb_dequeue(&sk->sk_write_queue); - if (err == 0) { - struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); - const int len = skb->len; +void dccp_write_xmit(struct sock *sk) +{ + struct dccp_sock *dp = dccp_sk(sk); + struct sk_buff *skb; - if (sk->sk_state == DCCP_PARTOPEN) { - /* See 8.1.5. Handshake Completion */ - inet_csk_schedule_ack(sk); - inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, - inet_csk(sk)->icsk_rto, - DCCP_RTO_MAX); - dcb->dccpd_type = DCCP_PKT_DATAACK; - } else if (dccp_ack_pending(sk)) - dcb->dccpd_type = DCCP_PKT_DATAACK; - else - dcb->dccpd_type = DCCP_PKT_DATA; - - err = dccp_transmit_skb(sk, skb); - ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len); - if (err) - DCCP_BUG("err=%d after ccid_hc_tx_packet_sent", - err); - } else { - dccp_pr_debug("packet discarded due to err=%d\n", err); - kfree_skb(skb); + while ((skb = dccp_qpolicy_top(sk))) { + int rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); + + switch (ccid_packet_dequeue_eval(rc)) { + case CCID_PACKET_WILL_DEQUEUE_LATER: + return; + case CCID_PACKET_DELAY: + sk_reset_timer(sk, &dp->dccps_xmit_timer, + jiffies + msecs_to_jiffies(rc)); + return; + case CCID_PACKET_SEND_AT_ONCE: + dccp_xmit_packet(sk); + break; + case CCID_PACKET_ERR: + dccp_qpolicy_drop(sk, skb); + dccp_pr_debug("packet discarded due to err=%d\n", rc); } } } @@ -339,10 +410,12 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE; DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss; - if (dccp_insert_options_rsk(dreq, skb)) { - kfree_skb(skb); - return NULL; - } + /* Resolve feature dependencies resulting from choice of CCID */ + if (dccp_feat_server_ccid_dependencies(dreq)) + goto response_failed; + + if (dccp_insert_options_rsk(dreq, skb)) + goto response_failed; /* Build and checksum header */ dh = dccp_zeroed_hdr(skb, dccp_header_size); @@ -363,6 +436,9 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, inet_rsk(req)->acked = 1; DCCP_INC_STATS(DCCP_MIB_OUTSEGS); return skb; +response_failed: + kfree_skb(skb); + return NULL; } EXPORT_SYMBOL_GPL(dccp_make_response); @@ -447,8 +523,9 @@ int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code) /* * Do all connect socket setups that can be done AF independent. */ -static inline void dccp_connect_init(struct sock *sk) +int dccp_connect(struct sock *sk) { + struct sk_buff *skb; struct dccp_sock *dp = dccp_sk(sk); struct dst_entry *dst = __sk_dst_get(sk); struct inet_connection_sock *icsk = inet_csk(sk); @@ -458,19 +535,13 @@ static inline void dccp_connect_init(struct sock *sk) dccp_sync_mss(sk, dst_mtu(dst)); + /* do not connect if feature negotiation setup fails */ + if (dccp_feat_finalise_settings(dccp_sk(sk))) + return -EPROTO; + /* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */ dp->dccps_gar = dp->dccps_iss; - icsk->icsk_retransmits = 0; -} - -int dccp_connect(struct sock *sk) -{ - struct sk_buff *skb; - struct inet_connection_sock *icsk = inet_csk(sk); - - dccp_connect_init(sk); - skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation); if (unlikely(skb == NULL)) return -ENOBUFS; @@ -480,11 +551,11 @@ int dccp_connect(struct sock *sk) DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST; - dccp_skb_entail(sk, skb); - dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL)); + dccp_transmit_skb(sk, dccp_skb_entail(sk, skb)); DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS); /* Timer for repeating the REQUEST until an answer. */ + icsk->icsk_retransmits = 0; inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, DCCP_RTO_MAX); return 0; @@ -571,6 +642,12 @@ void dccp_send_sync(struct sock *sk, const u64 ackno, DCCP_SKB_CB(skb)->dccpd_type = pkt_type; DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno; + /* + * Clear the flag in case the Sync was scheduled for out-of-band data, + * such as carrying a long Ack Vector. + */ + dccp_sk(sk)->dccps_sync_scheduled = 0; + dccp_transmit_skb(sk, skb); } @@ -599,9 +676,7 @@ void dccp_send_close(struct sock *sk, const int active) DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE; if (active) { - dccp_write_xmit(sk, 1); - dccp_skb_entail(sk, skb); - dccp_transmit_skb(sk, skb_clone(skb, prio)); + skb = dccp_skb_entail(sk, skb); /* * Retransmission timer for active-close: RFC 4340, 8.3 requires * to retransmit the Close/CloseReq until the CLOSING/CLOSEREQ @@ -614,6 +689,6 @@ void dccp_send_close(struct sock *sk, const int active) */ inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, DCCP_TIMEOUT_INIT, DCCP_RTO_MAX); - } else - dccp_transmit_skb(sk, skb); + } + dccp_transmit_skb(sk, skb); } diff --git a/net/dccp/probe.c b/net/dccp/probe.c index 81368a7f5379..eaa59d82ab0f 100644 --- a/net/dccp/probe.c +++ b/net/dccp/probe.c @@ -46,75 +46,54 @@ static struct { struct kfifo *fifo; spinlock_t lock; wait_queue_head_t wait; - struct timespec tstart; + ktime_t start; } dccpw; -static void printl(const char *fmt, ...) +static void jdccp_write_xmit(struct sock *sk) { - va_list args; - int len; - struct timespec now; - char tbuf[256]; - - va_start(args, fmt); - getnstimeofday(&now); - - now = timespec_sub(now, dccpw.tstart); - - len = sprintf(tbuf, "%lu.%06lu ", - (unsigned long) now.tv_sec, - (unsigned long) now.tv_nsec / NSEC_PER_USEC); - len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args); - va_end(args); - - kfifo_put(dccpw.fifo, tbuf, len); - wake_up(&dccpw.wait); -} - -static int jdccp_sendmsg(struct kiocb *iocb, struct sock *sk, - struct msghdr *msg, size_t size) -{ - const struct dccp_minisock *dmsk = dccp_msk(sk); const struct inet_sock *inet = inet_sk(sk); - const struct ccid3_hc_tx_sock *hctx; + struct ccid3_hc_tx_sock *hctx = NULL; + struct timespec tv; + char buf[256]; + int len, ccid = ccid_get_current_tx_ccid(dccp_sk(sk)); - if (dmsk->dccpms_tx_ccid == DCCPC_CCID3) + if (ccid == DCCPC_CCID3) hctx = ccid3_hc_tx_sk(sk); - else - hctx = NULL; - if (port == 0 || ntohs(inet->dport) == port || - ntohs(inet->sport) == port) { - if (hctx) - printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %d %d %d %u " - "%llu %llu %d\n", - NIPQUAD(inet->saddr), ntohs(inet->sport), - NIPQUAD(inet->daddr), ntohs(inet->dport), size, - hctx->ccid3hctx_s, hctx->ccid3hctx_rtt, - hctx->ccid3hctx_p, hctx->ccid3hctx_x_calc, - hctx->ccid3hctx_x_recv >> 6, - hctx->ccid3hctx_x >> 6, hctx->ccid3hctx_t_ipi); - else - printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d\n", + if (!port || ntohs(inet->dport) == port || ntohs(inet->sport) == port) { + + tv = ktime_to_timespec(ktime_sub(ktime_get(), dccpw.start)); + len = sprintf(buf, "%lu.%09lu %d.%d.%d.%d:%u %d.%d.%d.%d:%u %d", + (unsigned long)tv.tv_sec, + (unsigned long)tv.tv_nsec, NIPQUAD(inet->saddr), ntohs(inet->sport), - NIPQUAD(inet->daddr), ntohs(inet->dport), size); + NIPQUAD(inet->daddr), ntohs(inet->dport), ccid); + + if (hctx) + len += sprintf(buf + len, " %d %d %d %u %u %u %d", + hctx->s, hctx->rtt, hctx->p, hctx->x_calc, + (unsigned)(hctx->x_recv >> 6), + (unsigned)(hctx->x >> 6), hctx->t_ipi); + + len += sprintf(buf + len, "\n"); + kfifo_put(dccpw.fifo, buf, len); + wake_up(&dccpw.wait); } jprobe_return(); - return 0; } static struct jprobe dccp_send_probe = { .kp = { - .symbol_name = "dccp_sendmsg", + .symbol_name = "dccp_write_xmit", }, - .entry = jdccp_sendmsg, + .entry = jdccp_write_xmit, }; static int dccpprobe_open(struct inode *inode, struct file *file) { kfifo_reset(dccpw.fifo); - getnstimeofday(&dccpw.tstart); + dccpw.start = ktime_get(); return 0; } diff --git a/net/dccp/proto.c b/net/dccp/proto.c index d0bd34819761..ecf3be961e11 100644 --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -67,6 +67,9 @@ void dccp_set_state(struct sock *sk, const int state) case DCCP_OPEN: if (oldstate != DCCP_OPEN) DCCP_INC_STATS(DCCP_MIB_CURRESTAB); + /* Client retransmits all Confirm options until entering OPEN */ + if (oldstate == DCCP_PARTOPEN) + dccp_feat_list_purge(&dccp_sk(sk)->dccps_featneg); break; case DCCP_CLOSED: @@ -175,63 +178,25 @@ EXPORT_SYMBOL_GPL(dccp_state_name); int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized) { struct dccp_sock *dp = dccp_sk(sk); - struct dccp_minisock *dmsk = dccp_msk(sk); struct inet_connection_sock *icsk = inet_csk(sk); - dccp_minisock_init(&dp->dccps_minisock); - icsk->icsk_rto = DCCP_TIMEOUT_INIT; icsk->icsk_syn_retries = sysctl_dccp_request_retries; sk->sk_state = DCCP_CLOSED; sk->sk_write_space = dccp_write_space; icsk->icsk_sync_mss = dccp_sync_mss; - dp->dccps_mss_cache = 536; + dp->dccps_mss_cache = TCP_MIN_RCVMSS; dp->dccps_rate_last = jiffies; dp->dccps_role = DCCP_ROLE_UNDEFINED; dp->dccps_service = DCCP_SERVICE_CODE_IS_ABSENT; - dp->dccps_l_ack_ratio = dp->dccps_r_ack_ratio = 1; + dp->dccps_tx_qlen = sysctl_dccp_tx_qlen; dccp_init_xmit_timers(sk); - /* - * FIXME: We're hardcoding the CCID, and doing this at this point makes - * the listening (master) sock get CCID control blocks, which is not - * necessary, but for now, to not mess with the test userspace apps, - * lets leave it here, later the real solution is to do this in a - * setsockopt(CCIDs-I-want/accept). -acme - */ - if (likely(ctl_sock_initialized)) { - int rc = dccp_feat_init(dmsk); - - if (rc) - return rc; - - if (dmsk->dccpms_send_ack_vector) { - dp->dccps_hc_rx_ackvec = dccp_ackvec_alloc(GFP_KERNEL); - if (dp->dccps_hc_rx_ackvec == NULL) - return -ENOMEM; - } - dp->dccps_hc_rx_ccid = ccid_hc_rx_new(dmsk->dccpms_rx_ccid, - sk, GFP_KERNEL); - dp->dccps_hc_tx_ccid = ccid_hc_tx_new(dmsk->dccpms_tx_ccid, - sk, GFP_KERNEL); - if (unlikely(dp->dccps_hc_rx_ccid == NULL || - dp->dccps_hc_tx_ccid == NULL)) { - ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk); - ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk); - if (dmsk->dccpms_send_ack_vector) { - dccp_ackvec_free(dp->dccps_hc_rx_ackvec); - dp->dccps_hc_rx_ackvec = NULL; - } - dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL; - return -ENOMEM; - } - } else { - /* control socket doesn't need feat nego */ - INIT_LIST_HEAD(&dmsk->dccpms_pending); - INIT_LIST_HEAD(&dmsk->dccpms_conf); - } - + INIT_LIST_HEAD(&dp->dccps_featneg); + /* control socket doesn't need feat nego */ + if (likely(ctl_sock_initialized)) + return dccp_feat_init(sk); return 0; } @@ -240,7 +205,6 @@ EXPORT_SYMBOL_GPL(dccp_init_sock); void dccp_destroy_sock(struct sock *sk) { struct dccp_sock *dp = dccp_sk(sk); - struct dccp_minisock *dmsk = dccp_msk(sk); /* * DCCP doesn't use sk_write_queue, just sk_send_head @@ -258,7 +222,7 @@ void dccp_destroy_sock(struct sock *sk) kfree(dp->dccps_service_list); dp->dccps_service_list = NULL; - if (dmsk->dccpms_send_ack_vector) { + if (dp->dccps_hc_rx_ackvec != NULL) { dccp_ackvec_free(dp->dccps_hc_rx_ackvec); dp->dccps_hc_rx_ackvec = NULL; } @@ -267,7 +231,7 @@ void dccp_destroy_sock(struct sock *sk) dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL; /* clean up feature negotiation state */ - dccp_feat_clean(dmsk); + dccp_feat_list_purge(&dp->dccps_featneg); } EXPORT_SYMBOL_GPL(dccp_destroy_sock); @@ -277,6 +241,9 @@ static inline int dccp_listen_start(struct sock *sk, int backlog) struct dccp_sock *dp = dccp_sk(sk); dp->dccps_role = DCCP_ROLE_LISTEN; + /* do not start to listen if feature negotiation setup fails */ + if (dccp_feat_finalise_settings(dp)) + return -EPROTO; return inet_csk_listen_start(sk, backlog); } @@ -466,42 +433,70 @@ static int dccp_setsockopt_service(struct sock *sk, const __be32 service, return 0; } -/* byte 1 is feature. the rest is the preference list */ -static int dccp_setsockopt_change(struct sock *sk, int type, - struct dccp_so_feat __user *optval) +static int dccp_setsockopt_cscov(struct sock *sk, int cscov, bool rx) { - struct dccp_so_feat opt; - u8 *val; - int rc; + u8 *list, len; + int i, rc; - if (copy_from_user(&opt, optval, sizeof(opt))) - return -EFAULT; + if (cscov < 0 || cscov > 15) + return -EINVAL; /* - * rfc4340: 6.1. Change Options + * Populate a list of permissible values, in the range cscov...15. This + * is necessary since feature negotiation of single values only works if + * both sides incidentally choose the same value. Since the list starts + * lowest-value first, negotiation will pick the smallest shared value. */ - if (opt.dccpsf_len < 1) + if (cscov == 0) + return 0; + len = 16 - cscov; + + list = kmalloc(len, GFP_KERNEL); + if (list == NULL) + return -ENOBUFS; + + for (i = 0; i < len; i++) + list[i] = cscov++; + + rc = dccp_feat_register_sp(sk, DCCPF_MIN_CSUM_COVER, rx, list, len); + + if (rc == 0) { + if (rx) + dccp_sk(sk)->dccps_pcrlen = cscov; + else + dccp_sk(sk)->dccps_pcslen = cscov; + } + kfree(list); + return rc; +} + +static int dccp_setsockopt_ccid(struct sock *sk, int type, + char __user *optval, int optlen) +{ + u8 *val; + int rc = 0; + + if (optlen < 1 || optlen > DCCP_FEAT_MAX_SP_VALS) return -EINVAL; - val = kmalloc(opt.dccpsf_len, GFP_KERNEL); - if (!val) + val = kmalloc(optlen, GFP_KERNEL); + if (val == NULL) return -ENOMEM; - if (copy_from_user(val, opt.dccpsf_val, opt.dccpsf_len)) { - rc = -EFAULT; - goto out_free_val; + if (copy_from_user(val, optval, optlen)) { + kfree(val); + return -EFAULT; } - rc = dccp_feat_change(dccp_msk(sk), type, opt.dccpsf_feat, - val, opt.dccpsf_len, GFP_KERNEL); - if (rc) - goto out_free_val; + lock_sock(sk); + if (type == DCCP_SOCKOPT_TX_CCID || type == DCCP_SOCKOPT_CCID) + rc = dccp_feat_register_sp(sk, DCCPF_CCID, 1, val, optlen); -out: - return rc; + if (!rc && (type == DCCP_SOCKOPT_RX_CCID || type == DCCP_SOCKOPT_CCID)) + rc = dccp_feat_register_sp(sk, DCCPF_CCID, 0, val, optlen); + release_sock(sk); -out_free_val: kfree(val); - goto out; + return rc; } static int do_dccp_setsockopt(struct sock *sk, int level, int optname, @@ -510,7 +505,21 @@ static int do_dccp_setsockopt(struct sock *sk, int level, int optname, struct dccp_sock *dp = dccp_sk(sk); int val, err = 0; - if (optlen < sizeof(int)) + switch (optname) { + case DCCP_SOCKOPT_PACKET_SIZE: + DCCP_WARN("sockopt(PACKET_SIZE) is deprecated: fix your app\n"); + return 0; + case DCCP_SOCKOPT_CHANGE_L: + case DCCP_SOCKOPT_CHANGE_R: + DCCP_WARN("sockopt(CHANGE_L/R) is deprecated: fix your app\n"); + return 0; + case DCCP_SOCKOPT_CCID: + case DCCP_SOCKOPT_RX_CCID: + case DCCP_SOCKOPT_TX_CCID: + return dccp_setsockopt_ccid(sk, optname, optval, optlen); + } + + if (optlen < (int)sizeof(int)) return -EINVAL; if (get_user(val, (int __user *)optval)) @@ -521,53 +530,38 @@ static int do_dccp_setsockopt(struct sock *sk, int level, int optname, lock_sock(sk); switch (optname) { - case DCCP_SOCKOPT_PACKET_SIZE: - DCCP_WARN("sockopt(PACKET_SIZE) is deprecated: fix your app\n"); - err = 0; - break; - case DCCP_SOCKOPT_CHANGE_L: - if (optlen != sizeof(struct dccp_so_feat)) - err = -EINVAL; - else - err = dccp_setsockopt_change(sk, DCCPO_CHANGE_L, - (struct dccp_so_feat __user *) - optval); - break; - case DCCP_SOCKOPT_CHANGE_R: - if (optlen != sizeof(struct dccp_so_feat)) - err = -EINVAL; - else - err = dccp_setsockopt_change(sk, DCCPO_CHANGE_R, - (struct dccp_so_feat __user *) - optval); - break; case DCCP_SOCKOPT_SERVER_TIMEWAIT: if (dp->dccps_role != DCCP_ROLE_SERVER) err = -EOPNOTSUPP; else dp->dccps_server_timewait = (val != 0); break; - case DCCP_SOCKOPT_SEND_CSCOV: /* sender side, RFC 4340, sec. 9.2 */ - if (val < 0 || val > 15) + case DCCP_SOCKOPT_SEND_CSCOV: + err = dccp_setsockopt_cscov(sk, val, false); + break; + case DCCP_SOCKOPT_RECV_CSCOV: + err = dccp_setsockopt_cscov(sk, val, true); + break; + case DCCP_SOCKOPT_QPOLICY_ID: + if (sk->sk_state != DCCP_CLOSED) + err = -EISCONN; + else if (val < 0 || val >= DCCPQ_POLICY_MAX) err = -EINVAL; else - dp->dccps_pcslen = val; + dp->dccps_qpolicy = val; break; - case DCCP_SOCKOPT_RECV_CSCOV: /* receiver side, RFC 4340 sec. 9.2.1 */ - if (val < 0 || val > 15) + case DCCP_SOCKOPT_QPOLICY_TXQLEN: + if (val < 0) err = -EINVAL; - else { - dp->dccps_pcrlen = val; - /* FIXME: add feature negotiation, - * ChangeL(MinimumChecksumCoverage, val) */ - } + else + dp->dccps_tx_qlen = val; break; default: err = -ENOPROTOOPT; break; } - release_sock(sk); + return err; } @@ -648,6 +642,18 @@ static int do_dccp_getsockopt(struct sock *sk, int level, int optname, case DCCP_SOCKOPT_GET_CUR_MPS: val = dp->dccps_mss_cache; break; + case DCCP_SOCKOPT_AVAILABLE_CCIDS: + return ccid_getsockopt_builtin_ccids(sk, len, optval, optlen); + case DCCP_SOCKOPT_TX_CCID: + val = ccid_get_current_tx_ccid(dp); + if (val < 0) + return -ENOPROTOOPT; + break; + case DCCP_SOCKOPT_RX_CCID: + val = ccid_get_current_rx_ccid(dp); + if (val < 0) + return -ENOPROTOOPT; + break; case DCCP_SOCKOPT_SERVER_TIMEWAIT: val = dp->dccps_server_timewait; break; @@ -657,6 +663,12 @@ static int do_dccp_getsockopt(struct sock *sk, int level, int optname, case DCCP_SOCKOPT_RECV_CSCOV: val = dp->dccps_pcrlen; break; + case DCCP_SOCKOPT_QPOLICY_ID: + val = dp->dccps_qpolicy; + break; + case DCCP_SOCKOPT_QPOLICY_TXQLEN: + val = dp->dccps_tx_qlen; + break; case 128 ... 191: return ccid_hc_rx_getsockopt(dp->dccps_hc_rx_ccid, sk, optname, len, (u32 __user *)optval, optlen); @@ -699,6 +711,47 @@ int compat_dccp_getsockopt(struct sock *sk, int level, int optname, EXPORT_SYMBOL_GPL(compat_dccp_getsockopt); #endif +static int dccp_msghdr_parse(struct msghdr *msg, struct sk_buff *skb) +{ + struct cmsghdr *cmsg = CMSG_FIRSTHDR(msg); + + /* + * Assign an (opaque) qpolicy priority value to skb->priority. + * + * We are overloading this skb field for use with the qpolicy subystem. + * The skb->priority is normally used for the SO_PRIORITY option, which + * is initialised from sk_priority. Since the assignment of sk_priority + * to skb->priority happens later (on layer 3), we overload this field + * for use with queueing priorities as long as the skb is on layer 4. + * The default priority value (if nothing is set) is 0. + */ + skb->priority = 0; + + for (; cmsg != NULL; cmsg = CMSG_NXTHDR(msg, cmsg)) { + + if (!CMSG_OK(msg, cmsg)) + return -EINVAL; + + if (cmsg->cmsg_level != SOL_DCCP) + continue; + + if (cmsg->cmsg_type <= DCCP_SCM_QPOLICY_MAX && + !dccp_qpolicy_param_ok(skb->sk, cmsg->cmsg_type)) + return -EINVAL; + + switch (cmsg->cmsg_type) { + case DCCP_SCM_PRIORITY: + if (cmsg->cmsg_len != CMSG_LEN(sizeof(__u32))) + return -EINVAL; + skb->priority = *(__u32 *)CMSG_DATA(cmsg); + break; + default: + return -EINVAL; + } + } + return 0; +} + int dccp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len) { @@ -714,8 +767,7 @@ int dccp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, lock_sock(sk); - if (sysctl_dccp_tx_qlen && - (sk->sk_write_queue.qlen >= sysctl_dccp_tx_qlen)) { + if (dccp_qpolicy_full(sk)) { rc = -EAGAIN; goto out_release; } @@ -743,8 +795,12 @@ int dccp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, if (rc != 0) goto out_discard; - skb_queue_tail(&sk->sk_write_queue, skb); - dccp_write_xmit(sk,0); + rc = dccp_msghdr_parse(msg, skb); + if (rc != 0) + goto out_discard; + + dccp_qpolicy_push(sk, skb); + dccp_write_xmit(sk); out_release: release_sock(sk); return rc ? : len; @@ -967,9 +1023,22 @@ void dccp_close(struct sock *sk, long timeout) /* Check zero linger _after_ checking for unread data. */ sk->sk_prot->disconnect(sk, 0); } else if (sk->sk_state != DCCP_CLOSED) { + /* + * Normal connection termination. May need to wait if there are + * still packets in the TX queue that are delayed by the CCID. + */ + dccp_flush_write_queue(sk, &timeout); dccp_terminate_connection(sk); } + /* + * Flush write queue. This may be necessary in several cases: + * - we have been closed by the peer but still have application data; + * - abortive termination (unread data or zero linger time), + * - normal termination but queue could not be flushed within time limit + */ + __skb_queue_purge(&sk->sk_write_queue); + sk_stream_wait_close(sk, timeout); adjudge_to_death: diff --git a/net/dccp/qpolicy.c b/net/dccp/qpolicy.c new file mode 100644 index 000000000000..27383f88c75f --- /dev/null +++ b/net/dccp/qpolicy.c @@ -0,0 +1,137 @@ +/* + * net/dccp/qpolicy.c + * + * Policy-based packet dequeueing interface for DCCP. + * + * Copyright (c) 2008 Tomasz Grobelny <tomasz@grobelny.oswiecenia.net> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License v2 + * as published by the Free Software Foundation. + */ +#include "dccp.h" + +/* + * Simple Dequeueing Policy: + * If tx_qlen is different from 0, enqueue up to tx_qlen elements. + */ +static void qpolicy_simple_push(struct sock *sk, struct sk_buff *skb) +{ + skb_queue_tail(&sk->sk_write_queue, skb); +} + +static bool qpolicy_simple_full(struct sock *sk) +{ + return dccp_sk(sk)->dccps_tx_qlen && + sk->sk_write_queue.qlen >= dccp_sk(sk)->dccps_tx_qlen; +} + +static struct sk_buff *qpolicy_simple_top(struct sock *sk) +{ + return skb_peek(&sk->sk_write_queue); +} + +/* + * Priority-based Dequeueing Policy: + * If tx_qlen is different from 0 and the queue has reached its upper bound + * of tx_qlen elements, replace older packets lowest-priority-first. + */ +static struct sk_buff *qpolicy_prio_best_skb(struct sock *sk) +{ + struct sk_buff *skb, *best = NULL; + + skb_queue_walk(&sk->sk_write_queue, skb) + if (best == NULL || skb->priority > best->priority) + best = skb; + return best; +} + +static struct sk_buff *qpolicy_prio_worst_skb(struct sock *sk) +{ + struct sk_buff *skb, *worst = NULL; + + skb_queue_walk(&sk->sk_write_queue, skb) + if (worst == NULL || skb->priority < worst->priority) + worst = skb; + return worst; +} + +static bool qpolicy_prio_full(struct sock *sk) +{ + if (qpolicy_simple_full(sk)) + dccp_qpolicy_drop(sk, qpolicy_prio_worst_skb(sk)); + return false; +} + +/** + * struct dccp_qpolicy_operations - TX Packet Dequeueing Interface + * @push: add a new @skb to the write queue + * @full: indicates that no more packets will be admitted + * @top: peeks at whatever the queueing policy defines as its `top' + */ +static struct dccp_qpolicy_operations { + void (*push) (struct sock *sk, struct sk_buff *skb); + bool (*full) (struct sock *sk); + struct sk_buff* (*top) (struct sock *sk); + __be32 params; + +} qpol_table[DCCPQ_POLICY_MAX] = { + [DCCPQ_POLICY_SIMPLE] = { + .push = qpolicy_simple_push, + .full = qpolicy_simple_full, + .top = qpolicy_simple_top, + .params = 0, + }, + [DCCPQ_POLICY_PRIO] = { + .push = qpolicy_simple_push, + .full = qpolicy_prio_full, + .top = qpolicy_prio_best_skb, + .params = DCCP_SCM_PRIORITY, + }, +}; + +/* + * Externally visible interface + */ +void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb) +{ + qpol_table[dccp_sk(sk)->dccps_qpolicy].push(sk, skb); +} + +bool dccp_qpolicy_full(struct sock *sk) +{ + return qpol_table[dccp_sk(sk)->dccps_qpolicy].full(sk); +} + +void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb) +{ + if (skb != NULL) { + skb_unlink(skb, &sk->sk_write_queue); + kfree_skb(skb); + } +} + +struct sk_buff *dccp_qpolicy_top(struct sock *sk) +{ + return qpol_table[dccp_sk(sk)->dccps_qpolicy].top(sk); +} + +struct sk_buff *dccp_qpolicy_pop(struct sock *sk) +{ + struct sk_buff *skb = dccp_qpolicy_top(sk); + + /* Clear any skb fields that we used internally */ + skb->priority = 0; + + if (skb) + skb_unlink(skb, &sk->sk_write_queue); + return skb; +} + +bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param) +{ + /* check if exactly one bit is set */ + if (!param || (param & (param - 1))) + return false; + return (qpol_table[dccp_sk(sk)->dccps_qpolicy].params & param) == param; +} diff --git a/net/dccp/sysctl.c b/net/dccp/sysctl.c index 21295993fdb8..a5a1856234e7 100644 --- a/net/dccp/sysctl.c +++ b/net/dccp/sysctl.c @@ -18,76 +18,72 @@ #error This file should not be compiled without CONFIG_SYSCTL defined #endif +/* Boundary values */ +static int zero = 0, + u8_max = 0xFF; +static unsigned long seqw_min = 32; + static struct ctl_table dccp_default_table[] = { { .procname = "seq_window", - .data = &sysctl_dccp_feat_sequence_window, - .maxlen = sizeof(sysctl_dccp_feat_sequence_window), + .data = &sysctl_dccp_sequence_window, + .maxlen = sizeof(sysctl_dccp_sequence_window), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_doulongvec_minmax, + .extra1 = &seqw_min, /* RFC 4340, 7.5.2 */ }, { .procname = "rx_ccid", - .data = &sysctl_dccp_feat_rx_ccid, - .maxlen = sizeof(sysctl_dccp_feat_rx_ccid), + .data = &sysctl_dccp_rx_ccid, + .maxlen = sizeof(sysctl_dccp_rx_ccid), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &u8_max, /* RFC 4340, 10. */ }, { .procname = "tx_ccid", - .data = &sysctl_dccp_feat_tx_ccid, - .maxlen = sizeof(sysctl_dccp_feat_tx_ccid), - .mode = 0644, - .proc_handler = proc_dointvec, - }, - { - .procname = "ack_ratio", - .data = &sysctl_dccp_feat_ack_ratio, - .maxlen = sizeof(sysctl_dccp_feat_ack_ratio), - .mode = 0644, - .proc_handler = proc_dointvec, - }, - { - .procname = "send_ackvec", - .data = &sysctl_dccp_feat_send_ack_vector, - .maxlen = sizeof(sysctl_dccp_feat_send_ack_vector), - .mode = 0644, - .proc_handler = proc_dointvec, - }, - { - .procname = "send_ndp", - .data = &sysctl_dccp_feat_send_ndp_count, - .maxlen = sizeof(sysctl_dccp_feat_send_ndp_count), + .data = &sysctl_dccp_tx_ccid, + .maxlen = sizeof(sysctl_dccp_tx_ccid), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &u8_max, /* RFC 4340, 10. */ }, { .procname = "request_retries", .data = &sysctl_dccp_request_retries, .maxlen = sizeof(sysctl_dccp_request_retries), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &u8_max, }, { .procname = "retries1", .data = &sysctl_dccp_retries1, .maxlen = sizeof(sysctl_dccp_retries1), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &u8_max, }, { .procname = "retries2", .data = &sysctl_dccp_retries2, .maxlen = sizeof(sysctl_dccp_retries2), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &u8_max, }, { .procname = "tx_qlen", .data = &sysctl_dccp_tx_qlen, .maxlen = sizeof(sysctl_dccp_tx_qlen), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, }, { .procname = "sync_ratelimit", diff --git a/net/dccp/timer.c b/net/dccp/timer.c index 54b3c7e9e016..16359e29e7f5 100644 --- a/net/dccp/timer.c +++ b/net/dccp/timer.c @@ -87,17 +87,6 @@ static void dccp_retransmit_timer(struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); - /* retransmit timer is used for feature negotiation throughout - * connection. In this case, no packet is re-transmitted, but rather an - * ack is generated and pending changes are placed into its options. - */ - if (sk->sk_send_head == NULL) { - dccp_pr_debug("feat negotiation retransmit timeout %p\n", sk); - if (sk->sk_state == DCCP_OPEN) - dccp_send_ack(sk); - goto backoff; - } - /* * More than than 4MSL (8 minutes) has passed, a RESET(aborted) was * sent, no need to retransmit, this sock is dead. @@ -126,7 +115,6 @@ static void dccp_retransmit_timer(struct sock *sk) return; } -backoff: icsk->icsk_backoff++; icsk->icsk_rto = min(icsk->icsk_rto << 1, DCCP_RTO_MAX); @@ -249,32 +237,35 @@ out: sock_put(sk); } -/* Transmit-delay timer: used by the CCIDs to delay actual send time */ -static void dccp_write_xmit_timer(unsigned long data) +/** + * dccp_write_xmitlet - Workhorse for CCID packet dequeueing interface + * See the comments above %ccid_dequeueing_decision for supported modes. + */ +static void dccp_write_xmitlet(unsigned long data) { struct sock *sk = (struct sock *)data; - struct dccp_sock *dp = dccp_sk(sk); bh_lock_sock(sk); if (sock_owned_by_user(sk)) - sk_reset_timer(sk, &dp->dccps_xmit_timer, jiffies+1); + sk_reset_timer(sk, &dccp_sk(sk)->dccps_xmit_timer, jiffies + 1); else - dccp_write_xmit(sk, 0); + dccp_write_xmit(sk); bh_unlock_sock(sk); - sock_put(sk); } -static void dccp_init_write_xmit_timer(struct sock *sk) +static void dccp_write_xmit_timer(unsigned long data) { - struct dccp_sock *dp = dccp_sk(sk); - - setup_timer(&dp->dccps_xmit_timer, dccp_write_xmit_timer, - (unsigned long)sk); + dccp_write_xmitlet(data); + sock_put((struct sock *)data); } void dccp_init_xmit_timers(struct sock *sk) { - dccp_init_write_xmit_timer(sk); + struct dccp_sock *dp = dccp_sk(sk); + + tasklet_init(&dp->dccps_xmitlet, dccp_write_xmitlet, (unsigned long)sk); + setup_timer(&dp->dccps_xmit_timer, dccp_write_xmit_timer, + (unsigned long)sk); inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer, &dccp_keepalive_timer); } @@ -290,8 +281,7 @@ u32 dccp_timestamp(void) { s64 delta = ktime_us_delta(ktime_get_real(), dccp_timestamp_seed); - do_div(delta, 10); - return delta; + return div_u64(delta, DCCP_TIME_RESOLUTION); } EXPORT_SYMBOL_GPL(dccp_timestamp); diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index f79a51607292..9da9f19ece8a 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -811,25 +811,12 @@ void tcp_update_metrics(struct sock *sk) } } -/* Numbers are taken from RFC3390. - * - * John Heffner states: - * - * The RFC specifies a window of no more than 4380 bytes - * unless 2*MSS > 4380. Reading the pseudocode in the RFC - * is a bit misleading because they use a clamp at 4380 bytes - * rather than use a multiplier in the relevant range. - */ __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst) { __u32 cwnd = (dst ? dst_metric(dst, RTAX_INITCWND) : 0); - if (!cwnd) { - if (tp->mss_cache > 1460) - cwnd = 2; - else - cwnd = (tp->mss_cache > 1095) ? 3 : 4; - } + if (!cwnd) + cwnd = rfc3390_bytes_to_packets(tp->mss_cache); return min_t(__u32, cwnd, tp->snd_cwnd_clamp); } |