diff options
Diffstat (limited to 'net/ipv4/tcp_input.c')
| -rw-r--r-- | net/ipv4/tcp_input.c | 701 |
1 files changed, 319 insertions, 382 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index b224eb8bce8..432c36649db 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -88,12 +88,14 @@ int sysctl_tcp_app_win __read_mostly = 31; int sysctl_tcp_adv_win_scale __read_mostly = 1; EXPORT_SYMBOL(sysctl_tcp_adv_win_scale); +/* rfc5961 challenge ack rate limiting */ +int sysctl_tcp_challenge_ack_limit = 100; + int sysctl_tcp_stdurg __read_mostly; int sysctl_tcp_rfc1337 __read_mostly; int sysctl_tcp_max_orphans __read_mostly = NR_FILE; int sysctl_tcp_frto __read_mostly = 2; int sysctl_tcp_frto_response __read_mostly; -int sysctl_tcp_nometrics_save __read_mostly; int sysctl_tcp_thin_dupack __read_mostly; @@ -235,7 +237,11 @@ static inline void TCP_ECN_check_ce(struct tcp_sock *tp, const struct sk_buff *s tcp_enter_quickack_mode((struct sock *)tp); break; case INET_ECN_CE: - tp->ecn_flags |= TCP_ECN_DEMAND_CWR; + if (!(tp->ecn_flags & TCP_ECN_DEMAND_CWR)) { + /* Better not delay acks, sender can have a very low cwnd */ + tcp_enter_quickack_mode((struct sock *)tp); + tp->ecn_flags |= TCP_ECN_DEMAND_CWR; + } /* fallinto */ default: tp->ecn_flags |= TCP_ECN_SEEN; @@ -372,7 +378,7 @@ static void tcp_fixup_rcvbuf(struct sock *sk) /* 4. Try to fixup all. It is made immediately after connection enters * established state. */ -static void tcp_init_buffer_space(struct sock *sk) +void tcp_init_buffer_space(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); int maxwin; @@ -701,7 +707,7 @@ static void tcp_rtt_estimator(struct sock *sk, const __u32 mrtt) /* Calculate rto without backoff. This is the second half of Van Jacobson's * routine referred to above. */ -static inline void tcp_set_rto(struct sock *sk) +void tcp_set_rto(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); /* Old crap is replaced with new one. 8) @@ -728,109 +734,6 @@ static inline void tcp_set_rto(struct sock *sk) tcp_bound_rto(sk); } -/* Save metrics learned by this TCP session. - This function is called only, when TCP finishes successfully - i.e. when it enters TIME-WAIT or goes from LAST-ACK to CLOSE. - */ -void tcp_update_metrics(struct sock *sk) -{ - struct tcp_sock *tp = tcp_sk(sk); - struct dst_entry *dst = __sk_dst_get(sk); - - if (sysctl_tcp_nometrics_save) - return; - - dst_confirm(dst); - - if (dst && (dst->flags & DST_HOST)) { - const struct inet_connection_sock *icsk = inet_csk(sk); - int m; - unsigned long rtt; - - if (icsk->icsk_backoff || !tp->srtt) { - /* This session failed to estimate rtt. Why? - * Probably, no packets returned in time. - * Reset our results. - */ - if (!(dst_metric_locked(dst, RTAX_RTT))) - dst_metric_set(dst, RTAX_RTT, 0); - return; - } - - rtt = dst_metric_rtt(dst, RTAX_RTT); - m = rtt - tp->srtt; - - /* If newly calculated rtt larger than stored one, - * store new one. Otherwise, use EWMA. Remember, - * rtt overestimation is always better than underestimation. - */ - if (!(dst_metric_locked(dst, RTAX_RTT))) { - if (m <= 0) - set_dst_metric_rtt(dst, RTAX_RTT, tp->srtt); - else - set_dst_metric_rtt(dst, RTAX_RTT, rtt - (m >> 3)); - } - - if (!(dst_metric_locked(dst, RTAX_RTTVAR))) { - unsigned long var; - if (m < 0) - m = -m; - - /* Scale deviation to rttvar fixed point */ - m >>= 1; - if (m < tp->mdev) - m = tp->mdev; - - var = dst_metric_rtt(dst, RTAX_RTTVAR); - if (m >= var) - var = m; - else - var -= (var - m) >> 2; - - set_dst_metric_rtt(dst, RTAX_RTTVAR, var); - } - - if (tcp_in_initial_slowstart(tp)) { - /* Slow start still did not finish. */ - if (dst_metric(dst, RTAX_SSTHRESH) && - !dst_metric_locked(dst, RTAX_SSTHRESH) && - (tp->snd_cwnd >> 1) > dst_metric(dst, RTAX_SSTHRESH)) - dst_metric_set(dst, RTAX_SSTHRESH, tp->snd_cwnd >> 1); - if (!dst_metric_locked(dst, RTAX_CWND) && - tp->snd_cwnd > dst_metric(dst, RTAX_CWND)) - dst_metric_set(dst, RTAX_CWND, tp->snd_cwnd); - } else if (tp->snd_cwnd > tp->snd_ssthresh && - icsk->icsk_ca_state == TCP_CA_Open) { - /* Cong. avoidance phase, cwnd is reliable. */ - if (!dst_metric_locked(dst, RTAX_SSTHRESH)) - dst_metric_set(dst, RTAX_SSTHRESH, - max(tp->snd_cwnd >> 1, tp->snd_ssthresh)); - if (!dst_metric_locked(dst, RTAX_CWND)) - dst_metric_set(dst, RTAX_CWND, - (dst_metric(dst, RTAX_CWND) + - tp->snd_cwnd) >> 1); - } else { - /* Else slow start did not finish, cwnd is non-sense, - ssthresh may be also invalid. - */ - if (!dst_metric_locked(dst, RTAX_CWND)) - dst_metric_set(dst, RTAX_CWND, - (dst_metric(dst, RTAX_CWND) + - tp->snd_ssthresh) >> 1); - if (dst_metric(dst, RTAX_SSTHRESH) && - !dst_metric_locked(dst, RTAX_SSTHRESH) && - tp->snd_ssthresh > dst_metric(dst, RTAX_SSTHRESH)) - dst_metric_set(dst, RTAX_SSTHRESH, tp->snd_ssthresh); - } - - if (!dst_metric_locked(dst, RTAX_REORDERING)) { - if (dst_metric(dst, RTAX_REORDERING) < tp->reordering && - tp->reordering != sysctl_tcp_reordering) - dst_metric_set(dst, RTAX_REORDERING, tp->reordering); - } - } -} - __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst) { __u32 cwnd = (dst ? dst_metric(dst, RTAX_INITCWND) : 0); @@ -840,34 +743,11 @@ __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst) return min_t(__u32, cwnd, tp->snd_cwnd_clamp); } -/* Set slow start threshold and cwnd not falling to slow start */ -void tcp_enter_cwr(struct sock *sk, const int set_ssthresh) -{ - struct tcp_sock *tp = tcp_sk(sk); - const struct inet_connection_sock *icsk = inet_csk(sk); - - tp->prior_ssthresh = 0; - tp->bytes_acked = 0; - if (icsk->icsk_ca_state < TCP_CA_CWR) { - tp->undo_marker = 0; - if (set_ssthresh) - tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk); - tp->snd_cwnd = min(tp->snd_cwnd, - tcp_packets_in_flight(tp) + 1U); - tp->snd_cwnd_cnt = 0; - tp->high_seq = tp->snd_nxt; - tp->snd_cwnd_stamp = tcp_time_stamp; - TCP_ECN_queue_cwr(tp); - - tcp_set_ca_state(sk, TCP_CA_CWR); - } -} - /* * Packet counting of FACK is based on in-order assumptions, therefore TCP * disables it when reordering is detected */ -static void tcp_disable_fack(struct tcp_sock *tp) +void tcp_disable_fack(struct tcp_sock *tp) { /* RFC3517 uses different metric in lost marker => reset on change */ if (tcp_is_fack(tp)) @@ -881,86 +761,6 @@ static void tcp_dsack_seen(struct tcp_sock *tp) tp->rx_opt.sack_ok |= TCP_DSACK_SEEN; } -/* Initialize metrics on socket. */ - -static void tcp_init_metrics(struct sock *sk) -{ - struct tcp_sock *tp = tcp_sk(sk); - struct dst_entry *dst = __sk_dst_get(sk); - - if (dst == NULL) - goto reset; - - dst_confirm(dst); - - if (dst_metric_locked(dst, RTAX_CWND)) - tp->snd_cwnd_clamp = dst_metric(dst, RTAX_CWND); - if (dst_metric(dst, RTAX_SSTHRESH)) { - tp->snd_ssthresh = dst_metric(dst, RTAX_SSTHRESH); - if (tp->snd_ssthresh > tp->snd_cwnd_clamp) - tp->snd_ssthresh = tp->snd_cwnd_clamp; - } else { - /* ssthresh may have been reduced unnecessarily during. - * 3WHS. Restore it back to its initial default. - */ - tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; - } - if (dst_metric(dst, RTAX_REORDERING) && - tp->reordering != dst_metric(dst, RTAX_REORDERING)) { - tcp_disable_fack(tp); - tcp_disable_early_retrans(tp); - tp->reordering = dst_metric(dst, RTAX_REORDERING); - } - - if (dst_metric(dst, RTAX_RTT) == 0 || tp->srtt == 0) - goto reset; - - /* Initial rtt is determined from SYN,SYN-ACK. - * The segment is small and rtt may appear much - * less than real one. Use per-dst memory - * to make it more realistic. - * - * A bit of theory. RTT is time passed after "normal" sized packet - * is sent until it is ACKed. In normal circumstances sending small - * packets force peer to delay ACKs and calculation is correct too. - * The algorithm is adaptive and, provided we follow specs, it - * NEVER underestimate RTT. BUT! If peer tries to make some clever - * tricks sort of "quick acks" for time long enough to decrease RTT - * to low value, and then abruptly stops to do it and starts to delay - * ACKs, wait for troubles. - */ - if (dst_metric_rtt(dst, RTAX_RTT) > tp->srtt) { - tp->srtt = dst_metric_rtt(dst, RTAX_RTT); - tp->rtt_seq = tp->snd_nxt; - } - if (dst_metric_rtt(dst, RTAX_RTTVAR) > tp->mdev) { - tp->mdev = dst_metric_rtt(dst, RTAX_RTTVAR); - tp->mdev_max = tp->rttvar = max(tp->mdev, tcp_rto_min(sk)); - } - tcp_set_rto(sk); -reset: - if (tp->srtt == 0) { - /* RFC6298: 5.7 We've failed to get a valid RTT sample from - * 3WHS. This is most likely due to retransmission, - * including spurious one. Reset the RTO back to 3secs - * from the more aggressive 1sec to avoid more spurious - * retransmission. - */ - tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_FALLBACK; - inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK; - } - /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been - * retransmitted. In light of RFC6298 more aggressive 1sec - * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK - * retransmission has occurred. - */ - if (tp->total_retrans > 1) - tp->snd_cwnd = 1; - else - tp->snd_cwnd = tcp_init_cwnd(tp, dst); - tp->snd_cwnd_stamp = tcp_time_stamp; -} - static void tcp_update_reordering(struct sock *sk, const int metric, const int ts) { @@ -2670,39 +2470,10 @@ static inline void tcp_moderate_cwnd(struct tcp_sock *tp) tp->snd_cwnd_stamp = tcp_time_stamp; } -/* Lower bound on congestion window is slow start threshold - * unless congestion avoidance choice decides to overide it. - */ -static inline u32 tcp_cwnd_min(const struct sock *sk) -{ - const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; - - return ca_ops->min_cwnd ? ca_ops->min_cwnd(sk) : tcp_sk(sk)->snd_ssthresh; -} - -/* Decrease cwnd each second ack. */ -static void tcp_cwnd_down(struct sock *sk, int flag) -{ - struct tcp_sock *tp = tcp_sk(sk); - int decr = tp->snd_cwnd_cnt + 1; - - if ((flag & (FLAG_ANY_PROGRESS | FLAG_DSACKING_ACK)) || - (tcp_is_reno(tp) && !(flag & FLAG_NOT_DUP))) { - tp->snd_cwnd_cnt = decr & 1; - decr >>= 1; - - if (decr && tp->snd_cwnd > tcp_cwnd_min(sk)) - tp->snd_cwnd -= decr; - - tp->snd_cwnd = min(tp->snd_cwnd, tcp_packets_in_flight(tp) + 1); - tp->snd_cwnd_stamp = tcp_time_stamp; - } -} - /* Nothing was retransmitted or returned timestamp is less * than timestamp of the first retransmission. */ -static inline int tcp_packet_delayed(const struct tcp_sock *tp) +static inline bool tcp_packet_delayed(const struct tcp_sock *tp) { return !tp->retrans_stamp || (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr && @@ -2763,7 +2534,7 @@ static void tcp_undo_cwr(struct sock *sk, const bool undo_ssthresh) tp->snd_cwnd_stamp = tcp_time_stamp; } -static inline int tcp_may_undo(const struct tcp_sock *tp) +static inline bool tcp_may_undo(const struct tcp_sock *tp) { return tp->undo_marker && (!tp->undo_retrans || tcp_packet_delayed(tp)); } @@ -2900,24 +2671,80 @@ static bool tcp_try_undo_loss(struct sock *sk) return false; } -static inline void tcp_complete_cwr(struct sock *sk) +/* The cwnd reduction in CWR and Recovery use the PRR algorithm + * https://datatracker.ietf.org/doc/draft-ietf-tcpm-proportional-rate-reduction/ + * It computes the number of packets to send (sndcnt) based on packets newly + * delivered: + * 1) If the packets in flight is larger than ssthresh, PRR spreads the + * cwnd reductions across a full RTT. + * 2) If packets in flight is lower than ssthresh (such as due to excess + * losses and/or application stalls), do not perform any further cwnd + * reductions, but instead slow start up to ssthresh. + */ +static void tcp_init_cwnd_reduction(struct sock *sk, const bool set_ssthresh) +{ + struct tcp_sock *tp = tcp_sk(sk); + + tp->high_seq = tp->snd_nxt; + tp->bytes_acked = 0; + tp->snd_cwnd_cnt = 0; + tp->prior_cwnd = tp->snd_cwnd; + tp->prr_delivered = 0; + tp->prr_out = 0; + if (set_ssthresh) + tp->snd_ssthresh = inet_csk(sk)->icsk_ca_ops->ssthresh(sk); + TCP_ECN_queue_cwr(tp); +} + +static void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, + int fast_rexmit) { struct tcp_sock *tp = tcp_sk(sk); + int sndcnt = 0; + int delta = tp->snd_ssthresh - tcp_packets_in_flight(tp); - /* Do not moderate cwnd if it's already undone in cwr or recovery. */ - if (tp->undo_marker) { - if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR) { - tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh); - tp->snd_cwnd_stamp = tcp_time_stamp; - } else if (tp->snd_ssthresh < TCP_INFINITE_SSTHRESH) { - /* PRR algorithm. */ - tp->snd_cwnd = tp->snd_ssthresh; - tp->snd_cwnd_stamp = tcp_time_stamp; - } + tp->prr_delivered += newly_acked_sacked; + if (tcp_packets_in_flight(tp) > tp->snd_ssthresh) { + u64 dividend = (u64)tp->snd_ssthresh * tp->prr_delivered + + tp->prior_cwnd - 1; + sndcnt = div_u64(dividend, tp->prior_cwnd) - tp->prr_out; + } else { + sndcnt = min_t(int, delta, + max_t(int, tp->prr_delivered - tp->prr_out, + newly_acked_sacked) + 1); + } + + sndcnt = max(sndcnt, (fast_rexmit ? 1 : 0)); + tp->snd_cwnd = tcp_packets_in_flight(tp) + sndcnt; +} + +static inline void tcp_end_cwnd_reduction(struct sock *sk) +{ + struct tcp_sock *tp = tcp_sk(sk); + + /* Reset cwnd to ssthresh in CWR or Recovery (unless it's undone) */ + if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR || + (tp->undo_marker && tp->snd_ssthresh < TCP_INFINITE_SSTHRESH)) { + tp->snd_cwnd = tp->snd_ssthresh; + tp->snd_cwnd_stamp = tcp_time_stamp; } tcp_ca_event(sk, CA_EVENT_COMPLETE_CWR); } +/* Enter CWR state. Disable cwnd undo since congestion is proven with ECN */ +void tcp_enter_cwr(struct sock *sk, const int set_ssthresh) +{ + struct tcp_sock *tp = tcp_sk(sk); + + tp->prior_ssthresh = 0; + tp->bytes_acked = 0; + if (inet_csk(sk)->icsk_ca_state < TCP_CA_CWR) { + tp->undo_marker = 0; + tcp_init_cwnd_reduction(sk, set_ssthresh); + tcp_set_ca_state(sk, TCP_CA_CWR); + } +} + static void tcp_try_keep_open(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); @@ -2932,7 +2759,7 @@ static void tcp_try_keep_open(struct sock *sk) } } -static void tcp_try_to_open(struct sock *sk, int flag) +static void tcp_try_to_open(struct sock *sk, int flag, int newly_acked_sacked) { struct tcp_sock *tp = tcp_sk(sk); @@ -2949,7 +2776,7 @@ static void tcp_try_to_open(struct sock *sk, int flag) if (inet_csk(sk)->icsk_ca_state != TCP_CA_Open) tcp_moderate_cwnd(tp); } else { - tcp_cwnd_down(sk, flag); + tcp_cwnd_reduction(sk, newly_acked_sacked, 0); } } @@ -3031,38 +2858,6 @@ void tcp_simple_retransmit(struct sock *sk) } EXPORT_SYMBOL(tcp_simple_retransmit); -/* This function implements the PRR algorithm, specifcally the PRR-SSRB - * (proportional rate reduction with slow start reduction bound) as described in - * http://www.ietf.org/id/draft-mathis-tcpm-proportional-rate-reduction-01.txt. - * It computes the number of packets to send (sndcnt) based on packets newly - * delivered: - * 1) If the packets in flight is larger than ssthresh, PRR spreads the - * cwnd reductions across a full RTT. - * 2) If packets in flight is lower than ssthresh (such as due to excess - * losses and/or application stalls), do not perform any further cwnd - * reductions, but instead slow start up to ssthresh. - */ -static void tcp_update_cwnd_in_recovery(struct sock *sk, int newly_acked_sacked, - int fast_rexmit, int flag) -{ - struct tcp_sock *tp = tcp_sk(sk); - int sndcnt = 0; - int delta = tp->snd_ssthresh - tcp_packets_in_flight(tp); - - if (tcp_packets_in_flight(tp) > tp->snd_ssthresh) { - u64 dividend = (u64)tp->snd_ssthresh * tp->prr_delivered + - tp->prior_cwnd - 1; - sndcnt = div_u64(dividend, tp->prior_cwnd) - tp->prr_out; - } else { - sndcnt = min_t(int, delta, - max_t(int, tp->prr_delivered - tp->prr_out, - newly_acked_sacked) + 1); - } - - sndcnt = max(sndcnt, (fast_rexmit ? 1 : 0)); - tp->snd_cwnd = tcp_packets_in_flight(tp) + sndcnt; -} - static void tcp_enter_recovery(struct sock *sk, bool ece_ack) { struct tcp_sock *tp = tcp_sk(sk); @@ -3075,7 +2870,6 @@ static void tcp_enter_recovery(struct sock *sk, bool ece_ack) NET_INC_STATS_BH(sock_net(sk), mib_idx); - tp->high_seq = tp->snd_nxt; tp->prior_ssthresh = 0; tp->undo_marker = tp->snd_una; tp->undo_retrans = tp->retrans_out; @@ -3083,15 +2877,8 @@ static void tcp_enter_recovery(struct sock *sk, bool ece_ack) if (inet_csk(sk)->icsk_ca_state < TCP_CA_CWR) { if (!ece_ack) tp->prior_ssthresh = tcp_current_ssthresh(sk); - tp->snd_ssthresh = inet_csk(sk)->icsk_ca_ops->ssthresh(sk); - TCP_ECN_queue_cwr(tp); + tcp_init_cwnd_reduction(sk, true); } - - tp->bytes_acked = 0; - tp->snd_cwnd_cnt = 0; - tp->prior_cwnd = tp->snd_cwnd; - tp->prr_delivered = 0; - tp->prr_out = 0; tcp_set_ca_state(sk, TCP_CA_Recovery); } @@ -3107,13 +2894,14 @@ static void tcp_enter_recovery(struct sock *sk, bool ece_ack) * tcp_xmit_retransmit_queue(). */ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, - int newly_acked_sacked, bool is_dupack, + int prior_sacked, bool is_dupack, int flag) { struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); int do_lost = is_dupack || ((flag & FLAG_DATA_SACKED) && (tcp_fackets_out(tp) > tp->reordering)); + int newly_acked_sacked = 0; int fast_rexmit = 0; if (WARN_ON(!tp->packets_out && tp->sacked_out)) @@ -3150,7 +2938,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, /* CWR is to be held something *above* high_seq * is ACKed for CWR bit to reach receiver. */ if (tp->snd_una != tp->high_seq) { - tcp_complete_cwr(sk); + tcp_end_cwnd_reduction(sk); tcp_set_ca_state(sk, TCP_CA_Open); } break; @@ -3160,7 +2948,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, tcp_reset_reno_sack(tp); if (tcp_try_undo_recovery(sk)) return; - tcp_complete_cwr(sk); + tcp_end_cwnd_reduction(sk); break; } } @@ -3173,6 +2961,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, tcp_add_reno_sack(sk); } else do_lost = tcp_try_undo_partial(sk, pkts_acked); + newly_acked_sacked = pkts_acked + tp->sacked_out - prior_sacked; break; case TCP_CA_Loss: if (flag & FLAG_DATA_ACKED) @@ -3194,12 +2983,13 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, if (is_dupack) tcp_add_reno_sack(sk); } + newly_acked_sacked = pkts_acked + tp->sacked_out - prior_sacked; if (icsk->icsk_ca_state <= TCP_CA_Disorder) tcp_try_undo_dsack(sk); if (!tcp_time_to_recover(sk, flag)) { - tcp_try_to_open(sk, flag); + tcp_try_to_open(sk, flag, newly_acked_sacked); return; } @@ -3221,8 +3011,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, if (do_lost || (tcp_is_fack(tp) && tcp_head_timedout(sk))) tcp_update_scoreboard(sk, fast_rexmit); - tp->prr_delivered += newly_acked_sacked; - tcp_update_cwnd_in_recovery(sk, newly_acked_sacked, fast_rexmit, flag); + tcp_cwnd_reduction(sk, newly_acked_sacked, fast_rexmit); tcp_xmit_retransmit_queue(sk); } @@ -3301,6 +3090,12 @@ void tcp_rearm_rto(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); + /* If the retrans timer is currently being used by Fast Open + * for SYN-ACK retrans purpose, stay put. + */ + if (tp->fastopen_rsk) + return; + if (!tp->packets_out) { inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); } else { @@ -3552,23 +3347,23 @@ static void tcp_ack_probe(struct sock *sk) } } -static inline int tcp_ack_is_dubious(const struct sock *sk, const int flag) +static inline bool tcp_ack_is_dubious(const struct sock *sk, const int flag) { return !(flag & FLAG_NOT_DUP) || (flag & FLAG_CA_ALERT) || inet_csk(sk)->icsk_ca_state != TCP_CA_Open; } -static inline int tcp_may_raise_cwnd(const struct sock *sk, const int flag) +static inline bool tcp_may_raise_cwnd(const struct sock *sk, const int flag) { const struct tcp_sock *tp = tcp_sk(sk); return (!(flag & FLAG_ECE) || tp->snd_cwnd < tp->snd_ssthresh) && - !((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_Recovery | TCPF_CA_CWR)); + !tcp_in_cwnd_reduction(sk); } /* Check that window update is acceptable. * The function assumes that snd_una<=ack<=snd_next. */ -static inline int tcp_may_update_window(const struct tcp_sock *tp, +static inline bool tcp_may_update_window(const struct tcp_sock *tp, const u32 ack, const u32 ack_seq, const u32 nwin) { @@ -3630,9 +3425,9 @@ static void tcp_conservative_spur_to_response(struct tcp_sock *tp) } /* A conservative spurious RTO response algorithm: reduce cwnd using - * rate halving and continue in congestion avoidance. + * PRR and continue in congestion avoidance. */ -static void tcp_ratehalving_spur_to_response(struct sock *sk) +static void tcp_cwr_spur_to_response(struct sock *sk) { tcp_enter_cwr(sk, 0); } @@ -3640,7 +3435,7 @@ static void tcp_ratehalving_spur_to_response(struct sock *sk) static void tcp_undo_spur_to_response(struct sock *sk, int flag) { if (flag & FLAG_ECE) - tcp_ratehalving_spur_to_response(sk); + tcp_cwr_spur_to_response(sk); else tcp_undo_cwr(sk, true); } @@ -3747,7 +3542,7 @@ static bool tcp_process_frto(struct sock *sk, int flag) tcp_conservative_spur_to_response(tp); break; default: - tcp_ratehalving_spur_to_response(sk); + tcp_cwr_spur_to_response(sk); break; } tp->frto_counter = 0; @@ -3771,7 +3566,6 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) int prior_packets; int prior_sacked = tp->sacked_out; int pkts_acked = 0; - int newly_acked_sacked = 0; bool frto_cwnd = false; /* If the ack is older than previous acks @@ -3847,8 +3641,6 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) flag |= tcp_clean_rtx_queue(sk, prior_fackets, prior_snd_una); pkts_acked = prior_packets - tp->packets_out; - newly_acked_sacked = (prior_packets - prior_sacked) - - (tp->packets_out - tp->sacked_out); if (tp->frto_counter) frto_cwnd = tcp_process_frto(sk, flag); @@ -3862,22 +3654,24 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) tcp_may_raise_cwnd(sk, flag)) tcp_cong_avoid(sk, ack, prior_in_flight); is_dupack = !(flag & (FLAG_SND_UNA_ADVANCED | FLAG_NOT_DUP)); - tcp_fastretrans_alert(sk, pkts_acked, newly_acked_sacked, + tcp_fastretrans_alert(sk, pkts_acked, prior_sacked, is_dupack, flag); } else { if ((flag & FLAG_DATA_ACKED) && !frto_cwnd) tcp_cong_avoid(sk, ack, prior_in_flight); } - if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP)) - dst_confirm(__sk_dst_get(sk)); - + if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP)) { + struct dst_entry *dst = __sk_dst_get(sk); + if (dst) + dst_confirm(dst); + } return 1; no_queue: /* If data was DSACKed, see if we can undo a cwnd reduction. */ if (flag & FLAG_DSACKING_ACK) - tcp_fastretrans_alert(sk, pkts_acked, newly_acked_sacked, + tcp_fastretrans_alert(sk, pkts_acked, prior_sacked, is_dupack, flag); /* If this ack opens up a zero window, clear backoff. It was * being used to time the probes, and is probably far higher than @@ -3897,8 +3691,7 @@ old_ack: */ if (TCP_SKB_CB(skb)->sacked) { flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una); - newly_acked_sacked = tp->sacked_out - prior_sacked; - tcp_fastretrans_alert(sk, pkts_acked, newly_acked_sacked, + tcp_fastretrans_alert(sk, pkts_acked, prior_sacked, is_dupack, flag); } @@ -3911,7 +3704,8 @@ old_ack: * the fast version below fails. */ void tcp_parse_options(const struct sk_buff *skb, struct tcp_options_received *opt_rx, - const u8 **hvpp, int estab) + const u8 **hvpp, int estab, + struct tcp_fastopen_cookie *foc) { const unsigned char *ptr; const struct tcphdr *th = tcp_hdr(skb); @@ -4018,8 +3812,25 @@ void tcp_parse_options(const struct sk_buff *skb, struct tcp_options_received *o break; } break; - } + case TCPOPT_EXP: + /* Fast Open option shares code 254 using a + * 16 bits magic number. It's valid only in + * SYN or SYN-ACK with an even size. + */ + if (opsize < TCPOLEN_EXP_FASTOPEN_BASE || + get_unaligned_be16(ptr) != TCPOPT_FASTOPEN_MAGIC || + foc == NULL || !th->syn || (opsize & 1)) + break; + foc->len = opsize - TCPOLEN_EXP_FASTOPEN_BASE; + if (foc->len >= TCP_FASTOPEN_COOKIE_MIN && + foc->len <= TCP_FASTOPEN_COOKIE_MAX) + memcpy(foc->val, ptr + 2, foc->len); + else if (foc->len != 0) + foc->len = -1; + break; + + } ptr += opsize-2; length -= opsize; } @@ -4061,7 +3872,7 @@ static bool tcp_fast_parse_options(const struct sk_buff *skb, if (tcp_parse_aligned_timestamp(tp, th)) return true; } - tcp_parse_options(skb, &tp->rx_opt, hvpp, 1); + tcp_parse_options(skb, &tp->rx_opt, hvpp, 1, NULL); return true; } @@ -4167,7 +3978,7 @@ static int tcp_disordered_ack(const struct sock *sk, const struct sk_buff *skb) (s32)(tp->rx_opt.ts_recent - tp->rx_opt.rcv_tsval) <= (inet_csk(sk)->icsk_rto * 1024) / HZ); } -static inline int tcp_paws_discard(const struct sock *sk, +static inline bool tcp_paws_discard(const struct sock *sk, const struct sk_buff *skb) { const struct tcp_sock *tp = tcp_sk(sk); @@ -4189,14 +4000,14 @@ static inline int tcp_paws_discard(const struct sock *sk, * (borrowed from freebsd) */ -static inline int tcp_sequence(const struct tcp_sock *tp, u32 seq, u32 end_seq) +static inline bool tcp_sequence(const struct tcp_sock *tp, u32 seq, u32 end_seq) { return !before(end_seq, tp->rcv_wup) && !after(seq, tp->rcv_nxt + tcp_receive_window(tp)); } /* When we get a reset we do this. */ -static void tcp_reset(struct sock *sk) +void tcp_reset(struct sock *sk) { /* We want the right error as BSD sees it (and indeed as we do). */ switch (sk->sk_state) { @@ -4512,19 +4323,20 @@ static void tcp_ofo_queue(struct sock *sk) static bool tcp_prune_ofo_queue(struct sock *sk); static int tcp_prune_queue(struct sock *sk); -static int tcp_try_rmem_schedule(struct sock *sk, unsigned int size) +static int tcp_try_rmem_schedule(struct sock *sk, struct sk_buff *skb, + unsigned int size) { if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || - !sk_rmem_schedule(sk, size)) { + !sk_rmem_schedule(sk, skb, size)) { if (tcp_prune_queue(sk) < 0) return -1; - if (!sk_rmem_schedule(sk, size)) { + if (!sk_rmem_schedule(sk, skb, size)) { if (!tcp_prune_ofo_queue(sk)) return -1; - if (!sk_rmem_schedule(sk, size)) + if (!sk_rmem_schedule(sk, skb, size)) return -1; } } @@ -4579,8 +4391,8 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) TCP_ECN_check_ce(tp, skb); - if (tcp_try_rmem_schedule(sk, skb->truesize)) { - /* TODO: should increment a counter */ + if (unlikely(tcp_try_rmem_schedule(sk, skb, skb->truesize))) { + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPOFODROP); __kfree_skb(skb); return; } @@ -4589,6 +4401,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) tp->pred_flags = 0; inet_csk_schedule_ack(sk); + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPOFOQUEUE); SOCK_DEBUG(sk, "out of order segment: rcv_next %X seq %X - %X\n", tp->rcv_nxt, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq); @@ -4642,6 +4455,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) if (skb1 && before(seq, TCP_SKB_CB(skb1)->end_seq)) { if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq)) { /* All the bits are present. Drop. */ + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPOFOMERGE); __kfree_skb(skb); skb = NULL; tcp_dsack_set(sk, seq, end_seq); @@ -4680,6 +4494,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) __skb_unlink(skb1, &tp->out_of_order_queue); tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq, TCP_SKB_CB(skb1)->end_seq); + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPOFOMERGE); __kfree_skb(skb1); } @@ -4710,17 +4525,17 @@ static int __must_check tcp_queue_rcv(struct sock *sk, struct sk_buff *skb, int int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size) { - struct sk_buff *skb; + struct sk_buff *skb = NULL; struct tcphdr *th; bool fragstolen; - if (tcp_try_rmem_schedule(sk, size + sizeof(*th))) - goto err; - skb = alloc_skb(size + sizeof(*th), sk->sk_allocation); if (!skb) goto err; + if (tcp_try_rmem_schedule(sk, skb, size + sizeof(*th))) + goto err_free; + th = (struct tcphdr *)skb_put(skb, sizeof(*th)); skb_reset_transport_header(skb); memset(th, 0, sizeof(*th)); @@ -4791,7 +4606,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) if (eaten <= 0) { queue_and_out: if (eaten < 0 && - tcp_try_rmem_schedule(sk, skb->truesize)) + tcp_try_rmem_schedule(sk, skb, skb->truesize)) goto drop; eaten = tcp_queue_rcv(sk, skb, 0, &fragstolen); @@ -4819,7 +4634,7 @@ queue_and_out: if (eaten > 0) kfree_skb_partial(skb, fragstolen); - else if (!sock_flag(sk, SOCK_DEAD)) + if (!sock_flag(sk, SOCK_DEAD)) sk->sk_data_ready(sk, 0); return; } @@ -5372,7 +5187,7 @@ static __sum16 __tcp_checksum_complete_user(struct sock *sk, return result; } -static inline int tcp_checksum_complete_user(struct sock *sk, +static inline bool tcp_checksum_complete_user(struct sock *sk, struct sk_buff *skb) { return !skb_csum_unnecessary(skb) && @@ -5426,11 +5241,28 @@ out: } #endif /* CONFIG_NET_DMA */ +static void tcp_send_challenge_ack(struct sock *sk) +{ + /* unprotected vars, we dont care of overwrites */ + static u32 challenge_timestamp; + static unsigned int challenge_count; + u32 now = jiffies / HZ; + + if (now != challenge_timestamp) { + challenge_timestamp = now; + challenge_count = 0; + } + if (++challenge_count <= sysctl_tcp_challenge_ack_limit) { + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPCHALLENGEACK); + tcp_send_ack(sk); + } +} + /* Does PAWS and seqno based validation of an incoming segment, flags will * play significant role here. */ -static int tcp_validate_incoming(struct sock *sk, struct sk_buff *skb, - const struct tcphdr *th, int syn_inerr) +static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb, + const struct tcphdr *th, int syn_inerr) { const u8 *hash_location; struct tcp_sock *tp = tcp_sk(sk); @@ -5455,14 +5287,26 @@ static int tcp_validate_incoming(struct sock *sk, struct sk_buff *skb, * an acknowledgment should be sent in reply (unless the RST * bit is set, if so drop the segment and return)". */ - if (!th->rst) + if (!th->rst) { + if (th->syn) + goto syn_challenge; tcp_send_dupack(sk, skb); + } goto discard; } /* Step 2: check RST bit */ if (th->rst) { - tcp_reset(sk); + /* RFC 5961 3.2 : + * If sequence number exactly matches RCV.NXT, then + * RESET the connection + * else + * Send a challenge ACK + */ + if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt) + tcp_reset(sk); + else + tcp_send_challenge_ack(sk); goto discard; } @@ -5473,20 +5317,23 @@ static int tcp_validate_incoming(struct sock *sk, struct sk_buff *skb, /* step 3: check security and precedence [ignored] */ - /* step 4: Check for a SYN in window. */ - if (th->syn && !before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) { + /* step 4: Check for a SYN + * RFC 5691 4.2 : Send a challenge ack + */ + if (th->syn) { +syn_challenge: if (syn_inerr) TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS); - NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONSYN); - tcp_reset(sk); - return -1; + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSYNCHALLENGE); + tcp_send_challenge_ack(sk); + goto discard; } - return 1; + return true; discard: __kfree_skb(skb); - return 0; + return false; } /* @@ -5516,8 +5363,9 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb, const struct tcphdr *th, unsigned int len) { struct tcp_sock *tp = tcp_sk(sk); - int res; + if (unlikely(sk->sk_rx_dst == NULL)) + inet_csk(sk)->icsk_af_ops->sk_rx_dst_set(sk, skb); /* * Header prediction. * The code loosely follows the one in the famous @@ -5602,7 +5450,9 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb, if (tp->copied_seq == tp->rcv_nxt && len - tcp_header_len <= tp->ucopy.len) { #ifdef CONFIG_NET_DMA - if (tcp_dma_try_early_copy(sk, skb, tcp_header_len)) { + if (tp->ucopy.task == current && + sock_owned_by_user(sk) && + tcp_dma_try_early_copy(sk, skb, tcp_header_len)) { copied_early = 1; eaten = 1; } @@ -5679,8 +5529,7 @@ no_ack: #endif if (eaten) kfree_skb_partial(skb, fragstolen); - else - sk->sk_data_ready(sk, 0); + sk->sk_data_ready(sk, 0); return 0; } } @@ -5693,9 +5542,8 @@ slow_path: * Standard slow path. */ - res = tcp_validate_incoming(sk, skb, th, 1); - if (res <= 0) - return -res; + if (!tcp_validate_incoming(sk, skb, th, 1)) + return 0; step5: if (th->ack && tcp_ack(sk, skb, FLAG_SLOWPATH) < 0) @@ -5729,8 +5577,10 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb) tcp_set_state(sk, TCP_ESTABLISHED); - if (skb != NULL) + if (skb != NULL) { + icsk->icsk_af_ops->sk_rx_dst_set(sk, skb); security_inet_conn_established(sk, skb); + } /* Make sure socket is routed, for correct metrics. */ icsk->icsk_af_ops->rebuild_header(sk); @@ -5760,6 +5610,45 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb) } } +static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack, + struct tcp_fastopen_cookie *cookie) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct sk_buff *data = tp->syn_data ? tcp_write_queue_head(sk) : NULL; + u16 mss = tp->rx_opt.mss_clamp; + bool syn_drop; + + if (mss == tp->rx_opt.user_mss) { + struct tcp_options_received opt; + const u8 *hash_location; + + /* Get original SYNACK MSS value if user MSS sets mss_clamp */ + tcp_clear_options(&opt); + opt.user_mss = opt.mss_clamp = 0; + tcp_parse_options(synack, &opt, &hash_location, 0, NULL); + mss = opt.mss_clamp; + } + + if (!tp->syn_fastopen) /* Ignore an unsolicited cookie */ + cookie->len = -1; + + /* The SYN-ACK neither has cookie nor acknowledges the data. Presumably + * the remote receives only the retransmitted (regular) SYNs: either + * the original SYN-data or the corresponding SYN-ACK is lost. + */ + syn_drop = (cookie->len <= 0 && data && + inet_csk(sk)->icsk_retransmits); + + tcp_fastopen_cache_set(sk, mss, cookie, syn_drop); + + if (data) { /* Retransmit unacked data in SYN */ + tcp_retransmit_skb(sk, data); + tcp_rearm_rto(sk); + return true; + } + return false; +} + static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, const struct tcphdr *th, unsigned int len) { @@ -5767,9 +5656,10 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); struct tcp_cookie_values *cvp = tp->cookie_values; + struct tcp_fastopen_cookie foc = { .len = -1 }; int saved_clamp = tp->rx_opt.mss_clamp; - tcp_parse_options(skb, &tp->rx_opt, &hash_location, 0); + tcp_parse_options(skb, &tp->rx_opt, &hash_location, 0, &foc); if (th->ack) { /* rfc793: @@ -5779,11 +5669,9 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, * If SEG.ACK =< ISS, or SEG.ACK > SND.NXT, send * a reset (unless the RST bit is set, if so drop * the segment and return)" - * - * We do not send data with SYN, so that RFC-correct - * test reduces to: */ - if (TCP_SKB_CB(skb)->ack_seq != tp->snd_nxt) + if (!after(TCP_SKB_CB(skb)->ack_seq, tp->snd_una) || + after(TCP_SKB_CB(skb)->ack_seq, tp->snd_nxt)) goto reset_and_undo; if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr && @@ -5825,7 +5713,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, TCP_ECN_rcv_synack(tp, th); - tp->snd_wl1 = TCP_SKB_CB(skb)->seq; + tcp_init_wl(tp, TCP_SKB_CB(skb)->seq); tcp_ack(sk, skb, FLAG_SLOWPATH); /* Ok.. it's good. Set up sequence numbers and @@ -5838,7 +5726,6 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, * never scaled. */ tp->snd_wnd = ntohs(th->window); - tcp_init_wl(tp, TCP_SKB_CB(skb)->seq); if (!tp->rx_opt.wscale_ok) { tp->rx_opt.snd_wscale = tp->rx_opt.rcv_wscale = 0; @@ -5895,6 +5782,10 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, tcp_finish_connect(sk, skb); + if ((tp->syn_fastopen || tp->syn_data) && + tcp_rcv_fastopen_synack(sk, skb, &foc)) + return -1; + if (sk->sk_write_pending || icsk->icsk_accept_queue.rskq_defer_accept || icsk->icsk_ack.pingpong) { @@ -5972,7 +5863,9 @@ discard: tcp_send_synack(sk); #if 0 /* Note, we could accept data and URG from this segment. - * There are no obstacles to make this. + * There are no obstacles to make this (except that we must + * either change tcp_recvmsg() to prevent it from returning data + * before 3WHS completes per RFC793, or employ TCP Fast Open). * * However, if we ignore data in ACKless segments sometimes, * we have no reasons to accept it sometimes. @@ -6012,8 +5905,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, { struct tcp_sock *tp = tcp_sk(sk); struct inet_connection_sock *icsk = inet_csk(sk); + struct request_sock *req; int queued = 0; - int res; tp->rx_opt.saw_tstamp = 0; @@ -6068,9 +5961,16 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, return 0; } - res = tcp_validate_incoming(sk, skb, th, 0); - if (res <= 0) - return -res; + req = tp->fastopen_rsk; + if (req != NULL) { + BUG_ON(sk->sk_state != TCP_SYN_RECV && + sk->sk_state != TCP_FIN_WAIT1); + + if (tcp_check_req(sk, skb, req, NULL, true) == NULL) + goto discard; + } + if (!tcp_validate_incoming(sk, skb, th, 0)) + return 0; /* step 5: check the ACK field */ if (th->ack) { @@ -6079,7 +5979,25 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, switch (sk->sk_state) { case TCP_SYN_RECV: if (acceptable) { - tp->copied_seq = tp->rcv_nxt; + /* Once we leave TCP_SYN_RECV, we no longer + * need req so release it. + */ + if (req) { + tcp_synack_rtt_meas(sk, req); + tp->total_retrans = req->retrans; + + reqsk_fastopen_remove(sk, req, false); + } else { + /* Make sure socket is routed, for + * correct metrics. + */ + icsk->icsk_af_ops->rebuild_header(sk); + tcp_init_congestion_control(sk); + + tcp_mtup_init(sk); + tcp_init_buffer_space(sk); + tp->copied_seq = tp->rcv_nxt; + } smp_mb(); tcp_set_state(sk, TCP_ESTABLISHED); sk->sk_state_change(sk); @@ -6101,23 +6019,27 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, if (tp->rx_opt.tstamp_ok) tp->advmss -= TCPOLEN_TSTAMP_ALIGNED; - /* Make sure socket is routed, for - * correct metrics. - */ - icsk->icsk_af_ops->rebuild_header(sk); - - tcp_init_metrics(sk); - - tcp_init_congestion_control(sk); + if (req) { + /* Re-arm the timer because data may + * have been sent out. This is similar + * to the regular data transmission case + * when new data has just been ack'ed. + * + * (TFO) - we could try to be more + * aggressive and retranmitting any data + * sooner based on when they were sent + * out. + */ + tcp_rearm_rto(sk); + } else + tcp_init_metrics(sk); /* Prevent spurious tcp_cwnd_restart() on * first data packet. */ tp->lsndtime = tcp_time_stamp; - tcp_mtup_init(sk); tcp_initialize_rcv_mss(sk); - tcp_init_buffer_space(sk); tcp_fast_path_on(tp); } else { return 1; @@ -6125,10 +6047,25 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, break; case TCP_FIN_WAIT1: + /* If we enter the TCP_FIN_WAIT1 state and we are a + * Fast Open socket and this is the first acceptable + * ACK we have received, this would have acknowledged + * our SYNACK so stop the SYNACK timer. + */ + if (acceptable && req != NULL) { + /* We no longer need the request sock. */ + reqsk_fastopen_remove(sk, req, false); + tcp_rearm_rto(sk); + } if (tp->snd_una == tp->write_seq) { + struct dst_entry *dst; + tcp_set_state(sk, TCP_FIN_WAIT2); sk->sk_shutdown |= SEND_SHUTDOWN; - dst_confirm(__sk_dst_get(sk)); + + dst = __sk_dst_get(sk); + if (dst) + dst_confirm(dst); if (!sock_flag(sk, SOCK_DEAD)) /* Wake up lingering close() */ |