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Diffstat (limited to 'net/ipv4/tcp_output.c')
-rw-r--r--net/ipv4/tcp_output.c177
1 files changed, 122 insertions, 55 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 1db253e36045..8c8d7e06b72f 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -518,17 +518,26 @@ static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp,
if (unlikely(OPTION_FAST_OPEN_COOKIE & options)) {
struct tcp_fastopen_cookie *foc = opts->fastopen_cookie;
+ u8 *p = (u8 *)ptr;
+ u32 len; /* Fast Open option length */
+
+ if (foc->exp) {
+ len = TCPOLEN_EXP_FASTOPEN_BASE + foc->len;
+ *ptr = htonl((TCPOPT_EXP << 24) | (len << 16) |
+ TCPOPT_FASTOPEN_MAGIC);
+ p += TCPOLEN_EXP_FASTOPEN_BASE;
+ } else {
+ len = TCPOLEN_FASTOPEN_BASE + foc->len;
+ *p++ = TCPOPT_FASTOPEN;
+ *p++ = len;
+ }
- *ptr++ = htonl((TCPOPT_EXP << 24) |
- ((TCPOLEN_EXP_FASTOPEN_BASE + foc->len) << 16) |
- TCPOPT_FASTOPEN_MAGIC);
-
- memcpy(ptr, foc->val, foc->len);
- if ((foc->len & 3) == 2) {
- u8 *align = ((u8 *)ptr) + foc->len;
- align[0] = align[1] = TCPOPT_NOP;
+ memcpy(p, foc->val, foc->len);
+ if ((len & 3) == 2) {
+ p[foc->len] = TCPOPT_NOP;
+ p[foc->len + 1] = TCPOPT_NOP;
}
- ptr += (foc->len + 3) >> 2;
+ ptr += (len + 3) >> 2;
}
}
@@ -565,7 +574,7 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
opts->mss = tcp_advertise_mss(sk);
remaining -= TCPOLEN_MSS_ALIGNED;
- if (likely(sysctl_tcp_timestamps && *md5 == NULL)) {
+ if (likely(sysctl_tcp_timestamps && !*md5)) {
opts->options |= OPTION_TS;
opts->tsval = tcp_skb_timestamp(skb) + tp->tsoffset;
opts->tsecr = tp->rx_opt.ts_recent;
@@ -583,13 +592,17 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
}
if (fastopen && fastopen->cookie.len >= 0) {
- u32 need = TCPOLEN_EXP_FASTOPEN_BASE + fastopen->cookie.len;
+ u32 need = fastopen->cookie.len;
+
+ need += fastopen->cookie.exp ? TCPOLEN_EXP_FASTOPEN_BASE :
+ TCPOLEN_FASTOPEN_BASE;
need = (need + 3) & ~3U; /* Align to 32 bits */
if (remaining >= need) {
opts->options |= OPTION_FAST_OPEN_COOKIE;
opts->fastopen_cookie = &fastopen->cookie;
remaining -= need;
tp->syn_fastopen = 1;
+ tp->syn_fastopen_exp = fastopen->cookie.exp ? 1 : 0;
}
}
@@ -601,15 +614,14 @@ static unsigned int tcp_synack_options(struct sock *sk,
struct request_sock *req,
unsigned int mss, struct sk_buff *skb,
struct tcp_out_options *opts,
- struct tcp_md5sig_key **md5,
+ const struct tcp_md5sig_key *md5,
struct tcp_fastopen_cookie *foc)
{
struct inet_request_sock *ireq = inet_rsk(req);
unsigned int remaining = MAX_TCP_OPTION_SPACE;
#ifdef CONFIG_TCP_MD5SIG
- *md5 = tcp_rsk(req)->af_specific->md5_lookup(sk, req);
- if (*md5) {
+ if (md5) {
opts->options |= OPTION_MD5;
remaining -= TCPOLEN_MD5SIG_ALIGNED;
@@ -620,8 +632,6 @@ static unsigned int tcp_synack_options(struct sock *sk,
*/
ireq->tstamp_ok &= !ireq->sack_ok;
}
-#else
- *md5 = NULL;
#endif
/* We always send an MSS option. */
@@ -645,7 +655,10 @@ static unsigned int tcp_synack_options(struct sock *sk,
remaining -= TCPOLEN_SACKPERM_ALIGNED;
}
if (foc != NULL && foc->len >= 0) {
- u32 need = TCPOLEN_EXP_FASTOPEN_BASE + foc->len;
+ u32 need = foc->len;
+
+ need += foc->exp ? TCPOLEN_EXP_FASTOPEN_BASE :
+ TCPOLEN_FASTOPEN_BASE;
need = (need + 3) & ~3U; /* Align to 32 bits */
if (remaining >= need) {
opts->options |= OPTION_FAST_OPEN_COOKIE;
@@ -989,7 +1002,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
if (md5) {
sk_nocaps_add(sk, NETIF_F_GSO_MASK);
tp->af_specific->calc_md5_hash(opts.hash_location,
- md5, sk, NULL, skb);
+ md5, sk, skb);
}
#endif
@@ -1151,7 +1164,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
/* Get a new skb... force flag on. */
buff = sk_stream_alloc_skb(sk, nsize, gfp);
- if (buff == NULL)
+ if (!buff)
return -ENOMEM; /* We'll just try again later. */
sk->sk_wmem_queued += buff->truesize;
@@ -1354,6 +1367,8 @@ void tcp_mtup_init(struct sock *sk)
icsk->icsk_af_ops->net_header_len;
icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, net->ipv4.sysctl_tcp_base_mss);
icsk->icsk_mtup.probe_size = 0;
+ if (icsk->icsk_mtup.enabled)
+ icsk->icsk_mtup.probe_timestamp = tcp_time_stamp;
}
EXPORT_SYMBOL(tcp_mtup_init);
@@ -1708,7 +1723,7 @@ static int tso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len,
return tcp_fragment(sk, skb, len, mss_now, gfp);
buff = sk_stream_alloc_skb(sk, 0, gfp);
- if (unlikely(buff == NULL))
+ if (unlikely(!buff))
return -ENOMEM;
sk->sk_wmem_queued += buff->truesize;
@@ -1752,20 +1767,23 @@ static int tso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len,
static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
bool *is_cwnd_limited, u32 max_segs)
{
- struct tcp_sock *tp = tcp_sk(sk);
const struct inet_connection_sock *icsk = inet_csk(sk);
- u32 send_win, cong_win, limit, in_flight;
+ u32 age, send_win, cong_win, limit, in_flight;
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct skb_mstamp now;
+ struct sk_buff *head;
int win_divisor;
if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
goto send_now;
- if (icsk->icsk_ca_state != TCP_CA_Open)
+ if (!((1 << icsk->icsk_ca_state) & (TCPF_CA_Open | TCPF_CA_CWR)))
goto send_now;
- /* Defer for less than two clock ticks. */
- if (tp->tso_deferred &&
- (((u32)jiffies << 1) >> 1) - (tp->tso_deferred >> 1) > 1)
+ /* Avoid bursty behavior by allowing defer
+ * only if the last write was recent.
+ */
+ if ((s32)(tcp_time_stamp - tp->lsndtime) > 0)
goto send_now;
in_flight = tcp_packets_in_flight(tp);
@@ -1807,11 +1825,14 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
goto send_now;
}
- /* Ok, it looks like it is advisable to defer.
- * Do not rearm the timer if already set to not break TCP ACK clocking.
- */
- if (!tp->tso_deferred)
- tp->tso_deferred = 1 | (jiffies << 1);
+ head = tcp_write_queue_head(sk);
+ skb_mstamp_get(&now);
+ age = skb_mstamp_us_delta(&now, &head->skb_mstamp);
+ /* If next ACK is likely to come too late (half srtt), do not defer */
+ if (age < (tp->srtt_us >> 4))
+ goto send_now;
+
+ /* Ok, it looks like it is advisable to defer. */
if (cong_win < send_win && cong_win < skb->len)
*is_cwnd_limited = true;
@@ -1819,10 +1840,34 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
return true;
send_now:
- tp->tso_deferred = 0;
return false;
}
+static inline void tcp_mtu_check_reprobe(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct net *net = sock_net(sk);
+ u32 interval;
+ s32 delta;
+
+ interval = net->ipv4.sysctl_tcp_probe_interval;
+ delta = tcp_time_stamp - icsk->icsk_mtup.probe_timestamp;
+ if (unlikely(delta >= interval * HZ)) {
+ int mss = tcp_current_mss(sk);
+
+ /* Update current search range */
+ icsk->icsk_mtup.probe_size = 0;
+ icsk->icsk_mtup.search_high = tp->rx_opt.mss_clamp +
+ sizeof(struct tcphdr) +
+ icsk->icsk_af_ops->net_header_len;
+ icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss);
+
+ /* Update probe time stamp */
+ icsk->icsk_mtup.probe_timestamp = tcp_time_stamp;
+ }
+}
+
/* Create a new MTU probe if we are ready.
* MTU probe is regularly attempting to increase the path MTU by
* deliberately sending larger packets. This discovers routing
@@ -1837,11 +1882,13 @@ static int tcp_mtu_probe(struct sock *sk)
struct tcp_sock *tp = tcp_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
struct sk_buff *skb, *nskb, *next;
+ struct net *net = sock_net(sk);
int len;
int probe_size;
int size_needed;
int copy;
int mss_now;
+ int interval;
/* Not currently probing/verifying,
* not in recovery,
@@ -1854,12 +1901,25 @@ static int tcp_mtu_probe(struct sock *sk)
tp->rx_opt.num_sacks || tp->rx_opt.dsack)
return -1;
- /* Very simple search strategy: just double the MSS. */
+ /* Use binary search for probe_size between tcp_mss_base,
+ * and current mss_clamp. if (search_high - search_low)
+ * smaller than a threshold, backoff from probing.
+ */
mss_now = tcp_current_mss(sk);
- probe_size = 2 * tp->mss_cache;
+ probe_size = tcp_mtu_to_mss(sk, (icsk->icsk_mtup.search_high +
+ icsk->icsk_mtup.search_low) >> 1);
size_needed = probe_size + (tp->reordering + 1) * tp->mss_cache;
- if (probe_size > tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_high)) {
- /* TODO: set timer for probe_converge_event */
+ interval = icsk->icsk_mtup.search_high - icsk->icsk_mtup.search_low;
+ /* When misfortune happens, we are reprobing actively,
+ * and then reprobe timer has expired. We stick with current
+ * probing process by not resetting search range to its orignal.
+ */
+ if (probe_size > tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_high) ||
+ interval < net->ipv4.sysctl_tcp_probe_threshold) {
+ /* Check whether enough time has elaplased for
+ * another round of probing.
+ */
+ tcp_mtu_check_reprobe(sk);
return -1;
}
@@ -1881,7 +1941,8 @@ static int tcp_mtu_probe(struct sock *sk)
}
/* We're allowed to probe. Build it now. */
- if ((nskb = sk_stream_alloc_skb(sk, probe_size, GFP_ATOMIC)) == NULL)
+ nskb = sk_stream_alloc_skb(sk, probe_size, GFP_ATOMIC);
+ if (!nskb)
return -1;
sk->sk_wmem_queued += nskb->truesize;
sk_mem_charge(sk, nskb->truesize);
@@ -2179,7 +2240,7 @@ void tcp_send_loss_probe(struct sock *sk)
int mss = tcp_current_mss(sk);
int err = -1;
- if (tcp_send_head(sk) != NULL) {
+ if (tcp_send_head(sk)) {
err = tcp_write_xmit(sk, mss, TCP_NAGLE_OFF, 2, GFP_ATOMIC);
goto rearm_timer;
}
@@ -2689,7 +2750,7 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
if (skb == tcp_send_head(sk))
break;
/* we could do better than to assign each time */
- if (hole == NULL)
+ if (!hole)
tp->retransmit_skb_hint = skb;
/* Assume this retransmit will generate
@@ -2713,7 +2774,7 @@ begin_fwd:
if (!tcp_can_forward_retransmit(sk))
break;
/* Backtrack if necessary to non-L'ed skb */
- if (hole != NULL) {
+ if (hole) {
skb = hole;
hole = NULL;
}
@@ -2721,7 +2782,7 @@ begin_fwd:
goto begin_fwd;
} else if (!(sacked & TCPCB_LOST)) {
- if (hole == NULL && !(sacked & (TCPCB_SACKED_RETRANS|TCPCB_SACKED_ACKED)))
+ if (!hole && !(sacked & (TCPCB_SACKED_RETRANS|TCPCB_SACKED_ACKED)))
hole = skb;
continue;
@@ -2766,7 +2827,7 @@ void tcp_send_fin(struct sock *sk)
*/
mss_now = tcp_current_mss(sk);
- if (tcp_send_head(sk) != NULL) {
+ if (tcp_send_head(sk)) {
TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_FIN;
TCP_SKB_CB(skb)->end_seq++;
tp->write_seq++;
@@ -2824,14 +2885,14 @@ int tcp_send_synack(struct sock *sk)
struct sk_buff *skb;
skb = tcp_write_queue_head(sk);
- if (skb == NULL || !(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
+ if (!skb || !(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
pr_debug("%s: wrong queue state\n", __func__);
return -EFAULT;
}
if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK)) {
if (skb_cloned(skb)) {
struct sk_buff *nskb = skb_copy(skb, GFP_ATOMIC);
- if (nskb == NULL)
+ if (!nskb)
return -ENOMEM;
tcp_unlink_write_queue(skb, sk);
__skb_header_release(nskb);
@@ -2866,7 +2927,7 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
struct tcp_sock *tp = tcp_sk(sk);
struct tcphdr *th;
struct sk_buff *skb;
- struct tcp_md5sig_key *md5;
+ struct tcp_md5sig_key *md5 = NULL;
int tcp_header_size;
int mss;
@@ -2879,7 +2940,6 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
skb_reserve(skb, MAX_TCP_HEADER);
skb_dst_set(skb, dst);
- security_skb_owned_by(skb, sk);
mss = dst_metric_advmss(dst);
if (tp->rx_opt.user_mss && tp->rx_opt.user_mss < mss)
@@ -2892,7 +2952,12 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
else
#endif
skb_mstamp_get(&skb->skb_mstamp);
- tcp_header_size = tcp_synack_options(sk, req, mss, skb, &opts, &md5,
+
+#ifdef CONFIG_TCP_MD5SIG
+ rcu_read_lock();
+ md5 = tcp_rsk(req)->af_specific->req_md5_lookup(sk, req_to_sk(req));
+#endif
+ tcp_header_size = tcp_synack_options(sk, req, mss, skb, &opts, md5,
foc) + sizeof(*th);
skb_push(skb, tcp_header_size);
@@ -2923,12 +2988,14 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
#ifdef CONFIG_TCP_MD5SIG
/* Okay, we have all we need - do the md5 hash if needed */
- if (md5) {
+ if (md5)
tcp_rsk(req)->af_specific->calc_md5_hash(opts.hash_location,
- md5, NULL, req, skb);
- }
+ md5, req_to_sk(req), skb);
+ rcu_read_unlock();
#endif
+ /* Do not fool tcpdump (if any), clean our debris */
+ skb->tstamp.tv64 = 0;
return skb;
}
EXPORT_SYMBOL(tcp_make_synack);
@@ -2966,7 +3033,7 @@ static void tcp_connect_init(struct sock *sk)
(sysctl_tcp_timestamps ? TCPOLEN_TSTAMP_ALIGNED : 0);
#ifdef CONFIG_TCP_MD5SIG
- if (tp->af_specific->md5_lookup(sk, sk) != NULL)
+ if (tp->af_specific->md5_lookup(sk, sk))
tp->tcp_header_len += TCPOLEN_MD5SIG_ALIGNED;
#endif
@@ -3252,7 +3319,7 @@ void tcp_send_ack(struct sock *sk)
* sock.
*/
buff = alloc_skb(MAX_TCP_HEADER, sk_gfp_atomic(sk, GFP_ATOMIC));
- if (buff == NULL) {
+ if (!buff) {
inet_csk_schedule_ack(sk);
inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
@@ -3296,7 +3363,7 @@ static int tcp_xmit_probe_skb(struct sock *sk, int urgent)
/* We don't queue it, tcp_transmit_skb() sets ownership. */
skb = alloc_skb(MAX_TCP_HEADER, sk_gfp_atomic(sk, GFP_ATOMIC));
- if (skb == NULL)
+ if (!skb)
return -1;
/* Reserve space for headers and set control bits. */
@@ -3327,8 +3394,8 @@ int tcp_write_wakeup(struct sock *sk)
if (sk->sk_state == TCP_CLOSE)
return -1;
- if ((skb = tcp_send_head(sk)) != NULL &&
- before(TCP_SKB_CB(skb)->seq, tcp_wnd_end(tp))) {
+ skb = tcp_send_head(sk);
+ if (skb && before(TCP_SKB_CB(skb)->seq, tcp_wnd_end(tp))) {
int err;
unsigned int mss = tcp_current_mss(sk);
unsigned int seg_size = tcp_wnd_end(tp) - TCP_SKB_CB(skb)->seq;