/* Copyright (C) 2012-2016 B.A.T.M.A.N. contributors: * * Edo Monticelli, Antonio Quartulli * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . */ #include "tp_meter.h" #include "main.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "hard-interface.h" #include "log.h" #include "netlink.h" #include "originator.h" #include "packet.h" #include "send.h" /** * BATADV_TP_DEF_TEST_LENGTH - Default test length if not specified by the user * in milliseconds */ #define BATADV_TP_DEF_TEST_LENGTH 10000 /** * BATADV_TP_AWND - Advertised window by the receiver (in bytes) */ #define BATADV_TP_AWND 0x20000000 /** * BATADV_TP_RECV_TIMEOUT - Receiver activity timeout. If the receiver does not * get anything for such amount of milliseconds, the connection is killed */ #define BATADV_TP_RECV_TIMEOUT 1000 /** * BATADV_TP_MAX_RTO - Maximum sender timeout. If the sender RTO gets beyond * such amound of milliseconds, the receiver is considered unreachable and the * connection is killed */ #define BATADV_TP_MAX_RTO 30000 /** * BATADV_TP_FIRST_SEQ - First seqno of each session. The number is rather high * in order to immediately trigger a wrap around (test purposes) */ #define BATADV_TP_FIRST_SEQ ((u32)-1 - 2000) /** * BATADV_TP_PLEN - length of the payload (data after the batadv_unicast header) * to simulate */ #define BATADV_TP_PLEN (BATADV_TP_PACKET_LEN - ETH_HLEN - \ sizeof(struct batadv_unicast_packet)) static u8 batadv_tp_prerandom[4096] __read_mostly; /** * batadv_tp_session_cookie - generate session cookie based on session ids * @session: TP session identifier * @icmp_uid: icmp pseudo uid of the tp session * * Return: 32 bit tp_meter session cookie */ static u32 batadv_tp_session_cookie(const u8 session[2], u8 icmp_uid) { u32 cookie; cookie = icmp_uid << 16; cookie |= session[0] << 8; cookie |= session[1]; return cookie; } /** * batadv_tp_cwnd - compute the new cwnd size * @base: base cwnd size value * @increment: the value to add to base to get the new size * @min: minumim cwnd value (usually MSS) * * Return the new cwnd size and ensures it does not exceed the Advertised * Receiver Window size. It is wrap around safe. * For details refer to Section 3.1 of RFC5681 * * Return: new congestion window size in bytes */ static u32 batadv_tp_cwnd(u32 base, u32 increment, u32 min) { u32 new_size = base + increment; /* check for wrap-around */ if (new_size < base) new_size = (u32)ULONG_MAX; new_size = min_t(u32, new_size, BATADV_TP_AWND); return max_t(u32, new_size, min); } /** * batadv_tp_updated_cwnd - update the Congestion Windows * @tp_vars: the private data of the current TP meter session * @mss: maximum segment size of transmission * * 1) if the session is in Slow Start, the CWND has to be increased by 1 * MSS every unique received ACK * 2) if the session is in Congestion Avoidance, the CWND has to be * increased by MSS * MSS / CWND for every unique received ACK */ static void batadv_tp_update_cwnd(struct batadv_tp_vars *tp_vars, u32 mss) { spin_lock_bh(&tp_vars->cwnd_lock); /* slow start... */ if (tp_vars->cwnd <= tp_vars->ss_threshold) { tp_vars->dec_cwnd = 0; tp_vars->cwnd = batadv_tp_cwnd(tp_vars->cwnd, mss, mss); spin_unlock_bh(&tp_vars->cwnd_lock); return; } /* increment CWND at least of 1 (section 3.1 of RFC5681) */ tp_vars->dec_cwnd += max_t(u32, 1U << 3, ((mss * mss) << 6) / (tp_vars->cwnd << 3)); if (tp_vars->dec_cwnd < (mss << 3)) { spin_unlock_bh(&tp_vars->cwnd_lock); return; } tp_vars->cwnd = batadv_tp_cwnd(tp_vars->cwnd, mss, mss); tp_vars->dec_cwnd = 0; spin_unlock_bh(&tp_vars->cwnd_lock); } /** * batadv_tp_update_rto - calculate new retransmission timeout * @tp_vars: the private data of the current TP meter session * @new_rtt: new roundtrip time in msec */ static void batadv_tp_update_rto(struct batadv_tp_vars *tp_vars, u32 new_rtt) { long m = new_rtt; /* RTT update * Details in Section 2.2 and 2.3 of RFC6298 * * It's tricky to understand. Don't lose hair please. * Inspired by tcp_rtt_estimator() tcp_input.c */ if (tp_vars->srtt != 0) { m -= (tp_vars->srtt >> 3); /* m is now error in rtt est */ tp_vars->srtt += m; /* rtt = 7/8 srtt + 1/8 new */ if (m < 0) m = -m; m -= (tp_vars->rttvar >> 2); tp_vars->rttvar += m; /* mdev ~= 3/4 rttvar + 1/4 new */ } else { /* first measure getting in */ tp_vars->srtt = m << 3; /* take the measured time to be srtt */ tp_vars->rttvar = m << 1; /* new_rtt / 2 */ } /* rto = srtt + 4 * rttvar. * rttvar is scaled by 4, therefore doesn't need to be multiplied */ tp_vars->rto = (tp_vars->srtt >> 3) + tp_vars->rttvar; } /** * batadv_tp_batctl_notify - send client status result to client * @reason: reason for tp meter session stop * @dst: destination of tp_meter session * @bat_priv: the bat priv with all the soft interface information * @start_time: start of transmission in jiffies * @total_sent: bytes acked to the receiver * @cookie: cookie of tp_meter session */ static void batadv_tp_batctl_notify(enum batadv_tp_meter_reason reason, const u8 *dst, struct batadv_priv *bat_priv, unsigned long start_time, u64 total_sent, u32 cookie) { u32 test_time; u8 result; u32 total_bytes; if (!batadv_tp_is_error(reason)) { result = BATADV_TP_REASON_COMPLETE; test_time = jiffies_to_msecs(jiffies - start_time); total_bytes = total_sent; } else { result = reason; test_time = 0; total_bytes = 0; } batadv_netlink_tpmeter_notify(bat_priv, dst, result, test_time, total_bytes, cookie); } /** * batadv_tp_batctl_error_notify - send client error result to client * @reason: reason for tp meter session stop * @dst: destination of tp_meter session * @bat_priv: the bat priv with all the soft interface information * @cookie: cookie of tp_meter session */ static void batadv_tp_batctl_error_notify(enum batadv_tp_meter_reason reason, const u8 *dst, struct batadv_priv *bat_priv, u32 cookie) { batadv_tp_batctl_notify(reason, dst, bat_priv, 0, 0, cookie); } /** * batadv_tp_list_find - find a tp_vars object in the global list * @bat_priv: the bat priv with all the soft interface information * @dst: the other endpoint MAC address to look for * * Look for a tp_vars object matching dst as end_point and return it after * having incremented the refcounter. Return NULL is not found * * Return: matching tp_vars or NULL when no tp_vars with @dst was found */ static struct batadv_tp_vars *batadv_tp_list_find(struct batadv_priv *bat_priv, const u8 *dst) { struct batadv_tp_vars *pos, *tp_vars = NULL; rcu_read_lock(); hlist_for_each_entry_rcu(pos, &bat_priv->tp_list, list) { if (!batadv_compare_eth(pos->other_end, dst)) continue; /* most of the time this function is invoked during the normal * process..it makes sens to pay more when the session is * finished and to speed the process up during the measurement */ if (unlikely(!kref_get_unless_zero(&pos->refcount))) continue; tp_vars = pos; break; } rcu_read_unlock(); return tp_vars; } /** * batadv_tp_list_find_session - find tp_vars session object in the global list * @bat_priv: the bat priv with all the soft interface information * @dst: the other endpoint MAC address to look for * @session: session identifier * * Look for a tp_vars object matching dst as end_point, session as tp meter * session and return it after having incremented the refcounter. Return NULL * is not found * * Return: matching tp_vars or NULL when no tp_vars was found */ static struct batadv_tp_vars * batadv_tp_list_find_session(struct batadv_priv *bat_priv, const u8 *dst, const u8 *session) { struct batadv_tp_vars *pos, *tp_vars = NULL; rcu_read_lock(); hlist_for_each_entry_rcu(pos, &bat_priv->tp_list, list) { if (!batadv_compare_eth(pos->other_end, dst)) continue; if (memcmp(pos->session, session, sizeof(pos->session)) != 0) continue; /* most of the time this function is invoked during the normal * process..it makes sense to pay more when the session is * finished and to speed the process up during the measurement */ if (unlikely(!kref_get_unless_zero(&pos->refcount))) continue; tp_vars = pos; break; } rcu_read_unlock(); return tp_vars; } /** * batadv_tp_vars_release - release batadv_tp_vars from lists and queue for * free after rcu grace period * @ref: kref pointer of the batadv_tp_vars */ static void batadv_tp_vars_release(struct kref *ref) { struct batadv_tp_vars *tp_vars; struct batadv_tp_unacked *un, *safe; tp_vars = container_of(ref, struct batadv_tp_vars, refcount); /* lock should not be needed because this object is now out of any * context! */ spin_lock_bh(&tp_vars->unacked_lock); list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) { list_del(&un->list); kfree(un); } spin_unlock_bh(&tp_vars->unacked_lock); kfree_rcu(tp_vars, rcu); } /** * batadv_tp_vars_put - decrement the batadv_tp_vars refcounter and possibly * release it * @tp_vars: the private data of the current TP meter session to be free'd */ static void batadv_tp_vars_put(struct batadv_tp_vars *tp_vars) { kref_put(&tp_vars->refcount, batadv_tp_vars_release); } /** * batadv_tp_sender_cleanup - cleanup sender data and drop and timer * @bat_priv: the bat priv with all the soft interface information * @tp_vars: the private data of the current TP meter session to cleanup */ static void batadv_tp_sender_cleanup(struct batadv_priv *bat_priv, struct batadv_tp_vars *tp_vars) { cancel_delayed_work(&tp_vars->finish_work); spin_lock_bh(&tp_vars->bat_priv->tp_list_lock); hlist_del_rcu(&tp_vars->list); spin_unlock_bh(&tp_vars->bat_priv->tp_list_lock); /* drop list reference */ batadv_tp_vars_put(tp_vars); atomic_dec(&tp_vars->bat_priv->tp_num); /* kill the timer and remove its reference */ del_timer_sync(&tp_vars->timer); /* the worker might have rearmed itself therefore we kill it again. Note * that if the worker should run again before invoking the following * del_timer(), it would not re-arm itself once again because the status * is OFF now */ del_timer(&tp_vars->timer); batadv_tp_vars_put(tp_vars); } /** * batadv_tp_sender_end - print info about ended session and inform client * @bat_priv: the bat priv with all the soft interface information * @tp_vars: the private data of the current TP meter session */ static void batadv_tp_sender_end(struct batadv_priv *bat_priv, struct batadv_tp_vars *tp_vars) { u32 session_cookie; batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Test towards %pM finished..shutting down (reason=%d)\n", tp_vars->other_end, tp_vars->reason); batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Last timing stats: SRTT=%ums RTTVAR=%ums RTO=%ums\n", tp_vars->srtt >> 3, tp_vars->rttvar >> 2, tp_vars->rto); batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Final values: cwnd=%u ss_threshold=%u\n", tp_vars->cwnd, tp_vars->ss_threshold); session_cookie = batadv_tp_session_cookie(tp_vars->session, tp_vars->icmp_uid); batadv_tp_batctl_notify(tp_vars->reason, tp_vars->other_end, bat_priv, tp_vars->start_time, atomic64_read(&tp_vars->tot_sent), session_cookie); } /** * batadv_tp_sender_shutdown - let sender thread/timer stop gracefully * @tp_vars: the private data of the current TP meter session * @reason: reason for tp meter session stop */ static void batadv_tp_sender_shutdown(struct batadv_tp_vars *tp_vars, enum batadv_tp_meter_reason reason) { if (!atomic_dec_and_test(&tp_vars->sending)) return; tp_vars->reason = reason; } /** * batadv_tp_sender_finish - stop sender session after test_length was reached * @work: delayed work reference of the related tp_vars */ static void batadv_tp_sender_finish(struct work_struct *work) { struct delayed_work *delayed_work; struct batadv_tp_vars *tp_vars; delayed_work = to_delayed_work(work); tp_vars = container_of(delayed_work, struct batadv_tp_vars, finish_work); batadv_tp_sender_shutdown(tp_vars, BATADV_TP_REASON_COMPLETE); } /** * batadv_tp_reset_sender_timer - reschedule the sender timer * @tp_vars: the private TP meter data for this session * * Reschedule the timer using tp_vars->rto as delay */ static void batadv_tp_reset_sender_timer(struct batadv_tp_vars *tp_vars) { /* most of the time this function is invoked while normal packet * reception... */ if (unlikely(atomic_read(&tp_vars->sending) == 0)) /* timer ref will be dropped in batadv_tp_sender_cleanup */ return; mod_timer(&tp_vars->timer, jiffies + msecs_to_jiffies(tp_vars->rto)); } /** * batadv_tp_sender_timeout - timer that fires in case of packet loss * @arg: address of the related tp_vars * * If fired it means that there was packet loss. * Switch to Slow Start, set the ss_threshold to half of the current cwnd and * reset the cwnd to 3*MSS */ static void batadv_tp_sender_timeout(unsigned long arg) { struct batadv_tp_vars *tp_vars = (struct batadv_tp_vars *)arg; struct batadv_priv *bat_priv = tp_vars->bat_priv; if (atomic_read(&tp_vars->sending) == 0) return; /* if the user waited long enough...shutdown the test */ if (unlikely(tp_vars->rto >= BATADV_TP_MAX_RTO)) { batadv_tp_sender_shutdown(tp_vars, BATADV_TP_REASON_DST_UNREACHABLE); return; } /* RTO exponential backoff * Details in Section 5.5 of RFC6298 */ tp_vars->rto <<= 1; spin_lock_bh(&tp_vars->cwnd_lock); tp_vars->ss_threshold = tp_vars->cwnd >> 1; if (tp_vars->ss_threshold < BATADV_TP_PLEN * 2) tp_vars->ss_threshold = BATADV_TP_PLEN * 2; batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Meter: RTO fired during test towards %pM! cwnd=%u new ss_thr=%u, resetting last_sent to %u\n", tp_vars->other_end, tp_vars->cwnd, tp_vars->ss_threshold, atomic_read(&tp_vars->last_acked)); tp_vars->cwnd = BATADV_TP_PLEN * 3; spin_unlock_bh(&tp_vars->cwnd_lock); /* resend the non-ACKed packets.. */ tp_vars->last_sent = atomic_read(&tp_vars->last_acked); wake_up(&tp_vars->more_bytes); batadv_tp_reset_sender_timer(tp_vars); } /** * batadv_tp_fill_prerandom - Fill buffer with prefetched random bytes * @tp_vars: the private TP meter data for this session * @buf: Buffer to fill with bytes * @nbytes: amount of pseudorandom bytes */ static void batadv_tp_fill_prerandom(struct batadv_tp_vars *tp_vars, u8 *buf, size_t nbytes) { u32 local_offset; size_t bytes_inbuf; size_t to_copy; size_t pos = 0; spin_lock_bh(&tp_vars->prerandom_lock); local_offset = tp_vars->prerandom_offset; tp_vars->prerandom_offset += nbytes; tp_vars->prerandom_offset %= sizeof(batadv_tp_prerandom); spin_unlock_bh(&tp_vars->prerandom_lock); while (nbytes) { local_offset %= sizeof(batadv_tp_prerandom); bytes_inbuf = sizeof(batadv_tp_prerandom) - local_offset; to_copy = min(nbytes, bytes_inbuf); memcpy(&buf[pos], &batadv_tp_prerandom[local_offset], to_copy); pos += to_copy; nbytes -= to_copy; local_offset = 0; } } /** * batadv_tp_send_msg - send a single message * @tp_vars: the private TP meter data for this session * @src: source mac address * @orig_node: the originator of the destination * @seqno: sequence number of this packet * @len: length of the entire packet * @session: session identifier * @uid: local ICMP "socket" index * @timestamp: timestamp in jiffies which is replied in ack * * Create and send a single TP Meter message. * * Return: 0 on success, BATADV_TP_REASON_DST_UNREACHABLE if the destination is * not reachable, BATADV_TP_REASON_MEMORY_ERROR if the packet couldn't be * allocated */ static int batadv_tp_send_msg(struct batadv_tp_vars *tp_vars, const u8 *src, struct batadv_orig_node *orig_node, u32 seqno, size_t len, const u8 *session, int uid, u32 timestamp) { struct batadv_icmp_tp_packet *icmp; struct sk_buff *skb; int r; u8 *data; size_t data_len; skb = netdev_alloc_skb_ip_align(NULL, len + ETH_HLEN); if (unlikely(!skb)) return BATADV_TP_REASON_MEMORY_ERROR; skb_reserve(skb, ETH_HLEN); icmp = (struct batadv_icmp_tp_packet *)skb_put(skb, sizeof(*icmp)); /* fill the icmp header */ ether_addr_copy(icmp->dst, orig_node->orig); ether_addr_copy(icmp->orig, src); icmp->version = BATADV_COMPAT_VERSION; icmp->packet_type = BATADV_ICMP; icmp->ttl = BATADV_TTL; icmp->msg_type = BATADV_TP; icmp->uid = uid; icmp->subtype = BATADV_TP_MSG; memcpy(icmp->session, session, sizeof(icmp->session)); icmp->seqno = htonl(seqno); icmp->timestamp = htonl(timestamp); data_len = len - sizeof(*icmp); data = (u8 *)skb_put(skb, data_len); batadv_tp_fill_prerandom(tp_vars, data, data_len); r = batadv_send_skb_to_orig(skb, orig_node, NULL); if (r == NET_XMIT_SUCCESS) return 0; return BATADV_TP_REASON_CANT_SEND; } /** * batadv_tp_recv_ack - ACK receiving function * @bat_priv: the bat priv with all the soft interface information * @skb: the buffer containing the received packet * * Process a received TP ACK packet */ static void batadv_tp_recv_ack(struct batadv_priv *bat_priv, const struct sk_buff *skb) { struct batadv_hard_iface *primary_if = NULL; struct batadv_orig_node *orig_node = NULL; const struct batadv_icmp_tp_packet *icmp; struct batadv_tp_vars *tp_vars; size_t packet_len, mss; u32 rtt, recv_ack, cwnd; unsigned char *dev_addr; packet_len = BATADV_TP_PLEN; mss = BATADV_TP_PLEN; packet_len += sizeof(struct batadv_unicast_packet); icmp = (struct batadv_icmp_tp_packet *)skb->data; /* find the tp_vars */ tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig, icmp->session); if (unlikely(!tp_vars)) return; if (unlikely(atomic_read(&tp_vars->sending) == 0)) goto out; /* old ACK? silently drop it.. */ if (batadv_seq_before(ntohl(icmp->seqno), (u32)atomic_read(&tp_vars->last_acked))) goto out; primary_if = batadv_primary_if_get_selected(bat_priv); if (unlikely(!primary_if)) goto out; orig_node = batadv_orig_hash_find(bat_priv, icmp->orig); if (unlikely(!orig_node)) goto out; /* update RTO with the new sampled RTT, if any */ rtt = jiffies_to_msecs(jiffies) - ntohl(icmp->timestamp); if (icmp->timestamp && rtt) batadv_tp_update_rto(tp_vars, rtt); /* ACK for new data... reset the timer */ batadv_tp_reset_sender_timer(tp_vars); recv_ack = ntohl(icmp->seqno); /* check if this ACK is a duplicate */ if (atomic_read(&tp_vars->last_acked) == recv_ack) { atomic_inc(&tp_vars->dup_acks); if (atomic_read(&tp_vars->dup_acks) != 3) goto out; if (recv_ack >= tp_vars->recover) goto out; /* if this is the third duplicate ACK do Fast Retransmit */ batadv_tp_send_msg(tp_vars, primary_if->net_dev->dev_addr, orig_node, recv_ack, packet_len, icmp->session, icmp->uid, jiffies_to_msecs(jiffies)); spin_lock_bh(&tp_vars->cwnd_lock); /* Fast Recovery */ tp_vars->fast_recovery = true; /* Set recover to the last outstanding seqno when Fast Recovery * is entered. RFC6582, Section 3.2, step 1 */ tp_vars->recover = tp_vars->last_sent; tp_vars->ss_threshold = tp_vars->cwnd >> 1; batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Meter: Fast Recovery, (cur cwnd=%u) ss_thr=%u last_sent=%u recv_ack=%u\n", tp_vars->cwnd, tp_vars->ss_threshold, tp_vars->last_sent, recv_ack); tp_vars->cwnd = batadv_tp_cwnd(tp_vars->ss_threshold, 3 * mss, mss); tp_vars->dec_cwnd = 0; tp_vars->last_sent = recv_ack; spin_unlock_bh(&tp_vars->cwnd_lock); } else { /* count the acked data */ atomic64_add(recv_ack - atomic_read(&tp_vars->last_acked), &tp_vars->tot_sent); /* reset the duplicate ACKs counter */ atomic_set(&tp_vars->dup_acks, 0); if (tp_vars->fast_recovery) { /* partial ACK */ if (batadv_seq_before(recv_ack, tp_vars->recover)) { /* this is another hole in the window. React * immediately as specified by NewReno (see * Section 3.2 of RFC6582 for details) */ dev_addr = primary_if->net_dev->dev_addr; batadv_tp_send_msg(tp_vars, dev_addr, orig_node, recv_ack, packet_len, icmp->session, icmp->uid, jiffies_to_msecs(jiffies)); tp_vars->cwnd = batadv_tp_cwnd(tp_vars->cwnd, mss, mss); } else { tp_vars->fast_recovery = false; /* set cwnd to the value of ss_threshold at the * moment that Fast Recovery was entered. * RFC6582, Section 3.2, step 3 */ cwnd = batadv_tp_cwnd(tp_vars->ss_threshold, 0, mss); tp_vars->cwnd = cwnd; } goto move_twnd; } if (recv_ack - atomic_read(&tp_vars->last_acked) >= mss) batadv_tp_update_cwnd(tp_vars, mss); move_twnd: /* move the Transmit Window */ atomic_set(&tp_vars->last_acked, recv_ack); } wake_up(&tp_vars->more_bytes); out: if (likely(primary_if)) batadv_hardif_put(primary_if); if (likely(orig_node)) batadv_orig_node_put(orig_node); if (likely(tp_vars)) batadv_tp_vars_put(tp_vars); } /** * batadv_tp_avail - check if congestion window is not full * @tp_vars: the private data of the current TP meter session * @payload_len: size of the payload of a single message * * Return: true when congestion window is not full, false otherwise */ static bool batadv_tp_avail(struct batadv_tp_vars *tp_vars, size_t payload_len) { u32 win_left, win_limit; win_limit = atomic_read(&tp_vars->last_acked) + tp_vars->cwnd; win_left = win_limit - tp_vars->last_sent; return win_left >= payload_len; } /** * batadv_tp_wait_available - wait until congestion window becomes free or * timeout is reached * @tp_vars: the private data of the current TP meter session * @plen: size of the payload of a single message * * Return: 0 if the condition evaluated to false after the timeout elapsed, * 1 if the condition evaluated to true after the timeout elapsed, the * remaining jiffies (at least 1) if the condition evaluated to true before * the timeout elapsed, or -ERESTARTSYS if it was interrupted by a signal. */ static int batadv_tp_wait_available(struct batadv_tp_vars *tp_vars, size_t plen) { int ret; ret = wait_event_interruptible_timeout(tp_vars->more_bytes, batadv_tp_avail(tp_vars, plen), HZ / 10); return ret; } /** * batadv_tp_send - main sending thread of a tp meter session * @arg: address of the related tp_vars * * Return: nothing, this function never returns */ static int batadv_tp_send(void *arg) { struct batadv_tp_vars *tp_vars = arg; struct batadv_priv *bat_priv = tp_vars->bat_priv; struct batadv_hard_iface *primary_if = NULL; struct batadv_orig_node *orig_node = NULL; size_t payload_len, packet_len; int err = 0; if (unlikely(tp_vars->role != BATADV_TP_SENDER)) { err = BATADV_TP_REASON_DST_UNREACHABLE; tp_vars->reason = err; goto out; } orig_node = batadv_orig_hash_find(bat_priv, tp_vars->other_end); if (unlikely(!orig_node)) { err = BATADV_TP_REASON_DST_UNREACHABLE; tp_vars->reason = err; goto out; } primary_if = batadv_primary_if_get_selected(bat_priv); if (unlikely(!primary_if)) { err = BATADV_TP_REASON_DST_UNREACHABLE; goto out; } /* assume that all the hard_interfaces have a correctly * configured MTU, so use the soft_iface MTU as MSS. * This might not be true and in that case the fragmentation * should be used. * Now, try to send the packet as it is */ payload_len = BATADV_TP_PLEN; BUILD_BUG_ON(sizeof(struct batadv_icmp_tp_packet) > BATADV_TP_PLEN); batadv_tp_reset_sender_timer(tp_vars); /* queue the worker in charge of terminating the test */ queue_delayed_work(batadv_event_workqueue, &tp_vars->finish_work, msecs_to_jiffies(tp_vars->test_length)); while (atomic_read(&tp_vars->sending) != 0) { if (unlikely(!batadv_tp_avail(tp_vars, payload_len))) { batadv_tp_wait_available(tp_vars, payload_len); continue; } /* to emulate normal unicast traffic, add to the payload len * the size of the unicast header */ packet_len = payload_len + sizeof(struct batadv_unicast_packet); err = batadv_tp_send_msg(tp_vars, primary_if->net_dev->dev_addr, orig_node, tp_vars->last_sent, packet_len, tp_vars->session, tp_vars->icmp_uid, jiffies_to_msecs(jiffies)); /* something went wrong during the preparation/transmission */ if (unlikely(err && err != BATADV_TP_REASON_CANT_SEND)) { batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Meter: batadv_tp_send() cannot send packets (%d)\n", err); /* ensure nobody else tries to stop the thread now */ if (atomic_dec_and_test(&tp_vars->sending)) tp_vars->reason = err; break; } /* right-shift the TWND */ if (!err) tp_vars->last_sent += payload_len; cond_resched(); } out: if (likely(primary_if)) batadv_hardif_put(primary_if); if (likely(orig_node)) batadv_orig_node_put(orig_node); batadv_tp_sender_end(bat_priv, tp_vars); batadv_tp_sender_cleanup(bat_priv, tp_vars); batadv_tp_vars_put(tp_vars); do_exit(0); } /** * batadv_tp_start_kthread - start new thread which manages the tp meter sender * @tp_vars: the private data of the current TP meter session */ static void batadv_tp_start_kthread(struct batadv_tp_vars *tp_vars) { struct task_struct *kthread; struct batadv_priv *bat_priv = tp_vars->bat_priv; u32 session_cookie; kref_get(&tp_vars->refcount); kthread = kthread_create(batadv_tp_send, tp_vars, "kbatadv_tp_meter"); if (IS_ERR(kthread)) { session_cookie = batadv_tp_session_cookie(tp_vars->session, tp_vars->icmp_uid); pr_err("batadv: cannot create tp meter kthread\n"); batadv_tp_batctl_error_notify(BATADV_TP_REASON_MEMORY_ERROR, tp_vars->other_end, bat_priv, session_cookie); /* drop reserved reference for kthread */ batadv_tp_vars_put(tp_vars); /* cleanup of failed tp meter variables */ batadv_tp_sender_cleanup(bat_priv, tp_vars); return; } wake_up_process(kthread); } /** * batadv_tp_start - start a new tp meter session * @bat_priv: the bat priv with all the soft interface information * @dst: the receiver MAC address * @test_length: test length in milliseconds * @cookie: session cookie */ void batadv_tp_start(struct batadv_priv *bat_priv, const u8 *dst, u32 test_length, u32 *cookie) { struct batadv_tp_vars *tp_vars; u8 session_id[2]; u8 icmp_uid; u32 session_cookie; get_random_bytes(session_id, sizeof(session_id)); get_random_bytes(&icmp_uid, 1); session_cookie = batadv_tp_session_cookie(session_id, icmp_uid); *cookie = session_cookie; /* look for an already existing test towards this node */ spin_lock_bh(&bat_priv->tp_list_lock); tp_vars = batadv_tp_list_find(bat_priv, dst); if (tp_vars) { spin_unlock_bh(&bat_priv->tp_list_lock); batadv_tp_vars_put(tp_vars); batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Meter: test to or from the same node already ongoing, aborting\n"); batadv_tp_batctl_error_notify(BATADV_TP_REASON_ALREADY_ONGOING, dst, bat_priv, session_cookie); return; } if (!atomic_add_unless(&bat_priv->tp_num, 1, BATADV_TP_MAX_NUM)) { spin_unlock_bh(&bat_priv->tp_list_lock); batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Meter: too many ongoing sessions, aborting (SEND)\n"); batadv_tp_batctl_error_notify(BATADV_TP_REASON_TOO_MANY, dst, bat_priv, session_cookie); return; } tp_vars = kmalloc(sizeof(*tp_vars), GFP_ATOMIC); if (!tp_vars) { spin_unlock_bh(&bat_priv->tp_list_lock); batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Meter: batadv_tp_start cannot allocate list elements\n"); batadv_tp_batctl_error_notify(BATADV_TP_REASON_MEMORY_ERROR, dst, bat_priv, session_cookie); return; } /* initialize tp_vars */ ether_addr_copy(tp_vars->other_end, dst); kref_init(&tp_vars->refcount); tp_vars->role = BATADV_TP_SENDER; atomic_set(&tp_vars->sending, 1); memcpy(tp_vars->session, session_id, sizeof(session_id)); tp_vars->icmp_uid = icmp_uid; tp_vars->last_sent = BATADV_TP_FIRST_SEQ; atomic_set(&tp_vars->last_acked, BATADV_TP_FIRST_SEQ); tp_vars->fast_recovery = false; tp_vars->recover = BATADV_TP_FIRST_SEQ; /* initialise the CWND to 3*MSS (Section 3.1 in RFC5681). * For batman-adv the MSS is the size of the payload received by the * soft_interface, hence its MTU */ tp_vars->cwnd = BATADV_TP_PLEN * 3; /* at the beginning initialise the SS threshold to the biggest possible * window size, hence the AWND size */ tp_vars->ss_threshold = BATADV_TP_AWND; /* RTO initial value is 3 seconds. * Details in Section 2.1 of RFC6298 */ tp_vars->rto = 1000; tp_vars->srtt = 0; tp_vars->rttvar = 0; atomic64_set(&tp_vars->tot_sent, 0); kref_get(&tp_vars->refcount); setup_timer(&tp_vars->timer, batadv_tp_sender_timeout, (unsigned long)tp_vars); tp_vars->bat_priv = bat_priv; tp_vars->start_time = jiffies; init_waitqueue_head(&tp_vars->more_bytes); spin_lock_init(&tp_vars->unacked_lock); INIT_LIST_HEAD(&tp_vars->unacked_list); spin_lock_init(&tp_vars->cwnd_lock); tp_vars->prerandom_offset = 0; spin_lock_init(&tp_vars->prerandom_lock); kref_get(&tp_vars->refcount); hlist_add_head_rcu(&tp_vars->list, &bat_priv->tp_list); spin_unlock_bh(&bat_priv->tp_list_lock); tp_vars->test_length = test_length; if (!tp_vars->test_length) tp_vars->test_length = BATADV_TP_DEF_TEST_LENGTH; batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Meter: starting throughput meter towards %pM (length=%ums)\n", dst, test_length); /* init work item for finished tp tests */ INIT_DELAYED_WORK(&tp_vars->finish_work, batadv_tp_sender_finish); /* start tp kthread. This way the write() call issued from userspace can * happily return and avoid to block */ batadv_tp_start_kthread(tp_vars); /* don't return reference to new tp_vars */ batadv_tp_vars_put(tp_vars); } /** * batadv_tp_stop - stop currently running tp meter session * @bat_priv: the bat priv with all the soft interface information * @dst: the receiver MAC address * @return_value: reason for tp meter session stop */ void batadv_tp_stop(struct batadv_priv *bat_priv, const u8 *dst, u8 return_value) { struct batadv_orig_node *orig_node; struct batadv_tp_vars *tp_vars; batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Meter: stopping test towards %pM\n", dst); orig_node = batadv_orig_hash_find(bat_priv, dst); if (!orig_node) return; tp_vars = batadv_tp_list_find(bat_priv, orig_node->orig); if (!tp_vars) { batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Meter: trying to interrupt an already over connection\n"); goto out; } batadv_tp_sender_shutdown(tp_vars, return_value); batadv_tp_vars_put(tp_vars); out: batadv_orig_node_put(orig_node); } /** * batadv_tp_reset_receiver_timer - reset the receiver shutdown timer * @tp_vars: the private data of the current TP meter session * * start the receiver shutdown timer or reset it if already started */ static void batadv_tp_reset_receiver_timer(struct batadv_tp_vars *tp_vars) { mod_timer(&tp_vars->timer, jiffies + msecs_to_jiffies(BATADV_TP_RECV_TIMEOUT)); } /** * batadv_tp_receiver_shutdown - stop a tp meter receiver when timeout is * reached without received ack * @arg: address of the related tp_vars */ static void batadv_tp_receiver_shutdown(unsigned long arg) { struct batadv_tp_vars *tp_vars = (struct batadv_tp_vars *)arg; struct batadv_tp_unacked *un, *safe; struct batadv_priv *bat_priv; bat_priv = tp_vars->bat_priv; /* if there is recent activity rearm the timer */ if (!batadv_has_timed_out(tp_vars->last_recv_time, BATADV_TP_RECV_TIMEOUT)) { /* reset the receiver shutdown timer */ batadv_tp_reset_receiver_timer(tp_vars); return; } batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Shutting down for inactivity (more than %dms) from %pM\n", BATADV_TP_RECV_TIMEOUT, tp_vars->other_end); spin_lock_bh(&tp_vars->bat_priv->tp_list_lock); hlist_del_rcu(&tp_vars->list); spin_unlock_bh(&tp_vars->bat_priv->tp_list_lock); /* drop list reference */ batadv_tp_vars_put(tp_vars); atomic_dec(&bat_priv->tp_num); spin_lock_bh(&tp_vars->unacked_lock); list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) { list_del(&un->list); kfree(un); } spin_unlock_bh(&tp_vars->unacked_lock); /* drop reference of timer */ batadv_tp_vars_put(tp_vars); } /** * batadv_tp_send_ack - send an ACK packet * @bat_priv: the bat priv with all the soft interface information * @dst: the mac address of the destination originator * @seq: the sequence number to ACK * @timestamp: the timestamp to echo back in the ACK * @session: session identifier * @socket_index: local ICMP socket identifier * * Return: 0 on success, a positive integer representing the reason of the * failure otherwise */ static int batadv_tp_send_ack(struct batadv_priv *bat_priv, const u8 *dst, u32 seq, __be32 timestamp, const u8 *session, int socket_index) { struct batadv_hard_iface *primary_if = NULL; struct batadv_orig_node *orig_node; struct batadv_icmp_tp_packet *icmp; struct sk_buff *skb; int r, ret; orig_node = batadv_orig_hash_find(bat_priv, dst); if (unlikely(!orig_node)) { ret = BATADV_TP_REASON_DST_UNREACHABLE; goto out; } primary_if = batadv_primary_if_get_selected(bat_priv); if (unlikely(!primary_if)) { ret = BATADV_TP_REASON_DST_UNREACHABLE; goto out; } skb = netdev_alloc_skb_ip_align(NULL, sizeof(*icmp) + ETH_HLEN); if (unlikely(!skb)) { ret = BATADV_TP_REASON_MEMORY_ERROR; goto out; } skb_reserve(skb, ETH_HLEN); icmp = (struct batadv_icmp_tp_packet *)skb_put(skb, sizeof(*icmp)); icmp->packet_type = BATADV_ICMP; icmp->version = BATADV_COMPAT_VERSION; icmp->ttl = BATADV_TTL; icmp->msg_type = BATADV_TP; ether_addr_copy(icmp->dst, orig_node->orig); ether_addr_copy(icmp->orig, primary_if->net_dev->dev_addr); icmp->uid = socket_index; icmp->subtype = BATADV_TP_ACK; memcpy(icmp->session, session, sizeof(icmp->session)); icmp->seqno = htonl(seq); icmp->timestamp = timestamp; /* send the ack */ r = batadv_send_skb_to_orig(skb, orig_node, NULL); if (unlikely(r < 0) || (r == NET_XMIT_DROP)) { ret = BATADV_TP_REASON_DST_UNREACHABLE; goto out; } ret = 0; out: if (likely(orig_node)) batadv_orig_node_put(orig_node); if (likely(primary_if)) batadv_hardif_put(primary_if); return ret; } /** * batadv_tp_handle_out_of_order - store an out of order packet * @tp_vars: the private data of the current TP meter session * @skb: the buffer containing the received packet * * Store the out of order packet in the unacked list for late processing. This * packets are kept in this list so that they can be ACKed at once as soon as * all the previous packets have been received * * Return: true if the packed has been successfully processed, false otherwise */ static bool batadv_tp_handle_out_of_order(struct batadv_tp_vars *tp_vars, const struct sk_buff *skb) { const struct batadv_icmp_tp_packet *icmp; struct batadv_tp_unacked *un, *new; u32 payload_len; bool added = false; new = kmalloc(sizeof(*new), GFP_ATOMIC); if (unlikely(!new)) return false; icmp = (struct batadv_icmp_tp_packet *)skb->data; new->seqno = ntohl(icmp->seqno); payload_len = skb->len - sizeof(struct batadv_unicast_packet); new->len = payload_len; spin_lock_bh(&tp_vars->unacked_lock); /* if the list is empty immediately attach this new object */ if (list_empty(&tp_vars->unacked_list)) { list_add(&new->list, &tp_vars->unacked_list); goto out; } /* otherwise loop over the list and either drop the packet because this * is a duplicate or store it at the right position. * * The iteration is done in the reverse way because it is likely that * the last received packet (the one being processed now) has a bigger * seqno than all the others already stored. */ list_for_each_entry_reverse(un, &tp_vars->unacked_list, list) { /* check for duplicates */ if (new->seqno == un->seqno) { if (new->len > un->len) un->len = new->len; kfree(new); added = true; break; } /* look for the right position */ if (batadv_seq_before(new->seqno, un->seqno)) continue; /* as soon as an entry having a bigger seqno is found, the new * one is attached _after_ it. In this way the list is kept in * ascending order */ list_add_tail(&new->list, &un->list); added = true; break; } /* received packet with smallest seqno out of order; add it to front */ if (!added) list_add(&new->list, &tp_vars->unacked_list); out: spin_unlock_bh(&tp_vars->unacked_lock); return true; } /** * batadv_tp_ack_unordered - update number received bytes in current stream * without gaps * @tp_vars: the private data of the current TP meter session */ static void batadv_tp_ack_unordered(struct batadv_tp_vars *tp_vars) { struct batadv_tp_unacked *un, *safe; u32 to_ack; /* go through the unacked packet list and possibly ACK them as * well */ spin_lock_bh(&tp_vars->unacked_lock); list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) { /* the list is ordered, therefore it is possible to stop as soon * there is a gap between the last acked seqno and the seqno of * the packet under inspection */ if (batadv_seq_before(tp_vars->last_recv, un->seqno)) break; to_ack = un->seqno + un->len - tp_vars->last_recv; if (batadv_seq_before(tp_vars->last_recv, un->seqno + un->len)) tp_vars->last_recv += to_ack; list_del(&un->list); kfree(un); } spin_unlock_bh(&tp_vars->unacked_lock); } /** * batadv_tp_init_recv - return matching or create new receiver tp_vars * @bat_priv: the bat priv with all the soft interface information * @icmp: received icmp tp msg * * Return: corresponding tp_vars or NULL on errors */ static struct batadv_tp_vars * batadv_tp_init_recv(struct batadv_priv *bat_priv, const struct batadv_icmp_tp_packet *icmp) { struct batadv_tp_vars *tp_vars; spin_lock_bh(&bat_priv->tp_list_lock); tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig, icmp->session); if (tp_vars) goto out_unlock; if (!atomic_add_unless(&bat_priv->tp_num, 1, BATADV_TP_MAX_NUM)) { batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Meter: too many ongoing sessions, aborting (RECV)\n"); goto out_unlock; } tp_vars = kmalloc(sizeof(*tp_vars), GFP_ATOMIC); if (!tp_vars) goto out_unlock; ether_addr_copy(tp_vars->other_end, icmp->orig); tp_vars->role = BATADV_TP_RECEIVER; memcpy(tp_vars->session, icmp->session, sizeof(tp_vars->session)); tp_vars->last_recv = BATADV_TP_FIRST_SEQ; tp_vars->bat_priv = bat_priv; kref_init(&tp_vars->refcount); spin_lock_init(&tp_vars->unacked_lock); INIT_LIST_HEAD(&tp_vars->unacked_list); kref_get(&tp_vars->refcount); hlist_add_head_rcu(&tp_vars->list, &bat_priv->tp_list); kref_get(&tp_vars->refcount); setup_timer(&tp_vars->timer, batadv_tp_receiver_shutdown, (unsigned long)tp_vars); batadv_tp_reset_receiver_timer(tp_vars); out_unlock: spin_unlock_bh(&bat_priv->tp_list_lock); return tp_vars; } /** * batadv_tp_recv_msg - process a single data message * @bat_priv: the bat priv with all the soft interface information * @skb: the buffer containing the received packet * * Process a received TP MSG packet */ static void batadv_tp_recv_msg(struct batadv_priv *bat_priv, const struct sk_buff *skb) { const struct batadv_icmp_tp_packet *icmp; struct batadv_tp_vars *tp_vars; size_t packet_size; u32 seqno; icmp = (struct batadv_icmp_tp_packet *)skb->data; seqno = ntohl(icmp->seqno); /* check if this is the first seqno. This means that if the * first packet is lost, the tp meter does not work anymore! */ if (seqno == BATADV_TP_FIRST_SEQ) { tp_vars = batadv_tp_init_recv(bat_priv, icmp); if (!tp_vars) { batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Meter: seqno != BATADV_TP_FIRST_SEQ cannot initiate connection\n"); goto out; } } else { tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig, icmp->session); if (!tp_vars) { batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Unexpected packet from %pM!\n", icmp->orig); goto out; } } if (unlikely(tp_vars->role != BATADV_TP_RECEIVER)) { batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Meter: dropping packet: not expected (role=%u)\n", tp_vars->role); goto out; } tp_vars->last_recv_time = jiffies; /* if the packet is a duplicate, it may be the case that an ACK has been * lost. Resend the ACK */ if (batadv_seq_before(seqno, tp_vars->last_recv)) goto send_ack; /* if the packet is out of order enqueue it */ if (ntohl(icmp->seqno) != tp_vars->last_recv) { /* exit immediately (and do not send any ACK) if the packet has * not been enqueued correctly */ if (!batadv_tp_handle_out_of_order(tp_vars, skb)) goto out; /* send a duplicate ACK */ goto send_ack; } /* if everything was fine count the ACKed bytes */ packet_size = skb->len - sizeof(struct batadv_unicast_packet); tp_vars->last_recv += packet_size; /* check if this ordered message filled a gap.... */ batadv_tp_ack_unordered(tp_vars); send_ack: /* send the ACK. If the received packet was out of order, the ACK that * is going to be sent is a duplicate (the sender will count them and * possibly enter Fast Retransmit as soon as it has reached 3) */ batadv_tp_send_ack(bat_priv, icmp->orig, tp_vars->last_recv, icmp->timestamp, icmp->session, icmp->uid); out: if (likely(tp_vars)) batadv_tp_vars_put(tp_vars); } /** * batadv_tp_meter_recv - main TP Meter receiving function * @bat_priv: the bat priv with all the soft interface information * @skb: the buffer containing the received packet */ void batadv_tp_meter_recv(struct batadv_priv *bat_priv, struct sk_buff *skb) { struct batadv_icmp_tp_packet *icmp; icmp = (struct batadv_icmp_tp_packet *)skb->data; switch (icmp->subtype) { case BATADV_TP_MSG: batadv_tp_recv_msg(bat_priv, skb); break; case BATADV_TP_ACK: batadv_tp_recv_ack(bat_priv, skb); break; default: batadv_dbg(BATADV_DBG_TP_METER, bat_priv, "Received unknown TP Metric packet type %u\n", icmp->subtype); } consume_skb(skb); } /** * batadv_tp_meter_init - initialize global tp_meter structures */ void batadv_tp_meter_init(void) { get_random_bytes(batadv_tp_prerandom, sizeof(batadv_tp_prerandom)); }