diff options
Diffstat (limited to 'net/ipv4/tcp_input.c')
| -rw-r--r-- | net/ipv4/tcp_input.c | 517 |
1 files changed, 224 insertions, 293 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 9c6225780bd5..28af45abe062 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -347,24 +347,13 @@ static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb) } /* 3. Tuning rcvbuf, when connection enters established state. */ - static void tcp_fixup_rcvbuf(struct sock *sk) { u32 mss = tcp_sk(sk)->advmss; - u32 icwnd = TCP_DEFAULT_INIT_RCVWND; int rcvmem; - /* Limit to 10 segments if mss <= 1460, - * or 14600/mss segments, with a minimum of two segments. - */ - if (mss > 1460) - icwnd = max_t(u32, (1460 * TCP_DEFAULT_INIT_RCVWND) / mss, 2); - - rcvmem = SKB_TRUESIZE(mss + MAX_TCP_HEADER); - while (tcp_win_from_space(rcvmem) < mss) - rcvmem += 128; - - rcvmem *= icwnd; + rcvmem = 2 * SKB_TRUESIZE(mss + MAX_TCP_HEADER) * + tcp_default_init_rwnd(mss); if (sk->sk_rcvbuf < rcvmem) sk->sk_rcvbuf = min(rcvmem, sysctl_tcp_rmem[2]); @@ -1257,8 +1246,6 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb, if (skb == tp->retransmit_skb_hint) tp->retransmit_skb_hint = prev; - if (skb == tp->scoreboard_skb_hint) - tp->scoreboard_skb_hint = prev; if (skb == tp->lost_skb_hint) { tp->lost_skb_hint = prev; tp->lost_cnt_hint -= tcp_skb_pcount(prev); @@ -1966,20 +1953,6 @@ static bool tcp_pause_early_retransmit(struct sock *sk, int flag) return true; } -static inline int tcp_skb_timedout(const struct sock *sk, - const struct sk_buff *skb) -{ - return tcp_time_stamp - TCP_SKB_CB(skb)->when > inet_csk(sk)->icsk_rto; -} - -static inline int tcp_head_timedout(const struct sock *sk) -{ - const struct tcp_sock *tp = tcp_sk(sk); - - return tp->packets_out && - tcp_skb_timedout(sk, tcp_write_queue_head(sk)); -} - /* Linux NewReno/SACK/FACK/ECN state machine. * -------------------------------------- * @@ -2086,12 +2059,6 @@ static bool tcp_time_to_recover(struct sock *sk, int flag) if (tcp_dupack_heuristics(tp) > tp->reordering) return true; - /* Trick#3 : when we use RFC2988 timer restart, fast - * retransmit can be triggered by timeout of queue head. - */ - if (tcp_is_fack(tp) && tcp_head_timedout(sk)) - return true; - /* Trick#4: It is still not OK... But will it be useful to delay * recovery more? */ @@ -2128,44 +2095,6 @@ static bool tcp_time_to_recover(struct sock *sk, int flag) return false; } -/* New heuristics: it is possible only after we switched to restart timer - * each time when something is ACKed. Hence, we can detect timed out packets - * during fast retransmit without falling to slow start. - * - * Usefulness of this as is very questionable, since we should know which of - * the segments is the next to timeout which is relatively expensive to find - * in general case unless we add some data structure just for that. The - * current approach certainly won't find the right one too often and when it - * finally does find _something_ it usually marks large part of the window - * right away (because a retransmission with a larger timestamp blocks the - * loop from advancing). -ij - */ -static void tcp_timeout_skbs(struct sock *sk) -{ - struct tcp_sock *tp = tcp_sk(sk); - struct sk_buff *skb; - - if (!tcp_is_fack(tp) || !tcp_head_timedout(sk)) - return; - - skb = tp->scoreboard_skb_hint; - if (tp->scoreboard_skb_hint == NULL) - skb = tcp_write_queue_head(sk); - - tcp_for_write_queue_from(skb, sk) { - if (skb == tcp_send_head(sk)) - break; - if (!tcp_skb_timedout(sk, skb)) - break; - - tcp_skb_mark_lost(tp, skb); - } - - tp->scoreboard_skb_hint = skb; - - tcp_verify_left_out(tp); -} - /* Detect loss in event "A" above by marking head of queue up as lost. * For FACK or non-SACK(Reno) senders, the first "packets" number of segments * are considered lost. For RFC3517 SACK, a segment is considered lost if it @@ -2251,8 +2180,6 @@ static void tcp_update_scoreboard(struct sock *sk, int fast_rexmit) else if (fast_rexmit) tcp_mark_head_lost(sk, 1, 1); } - - tcp_timeout_skbs(sk); } /* CWND moderation, preventing bursts due to too big ACKs @@ -2307,10 +2234,22 @@ static void DBGUNDO(struct sock *sk, const char *msg) #define DBGUNDO(x...) do { } while (0) #endif -static void tcp_undo_cwr(struct sock *sk, const bool undo_ssthresh) +static void tcp_undo_cwnd_reduction(struct sock *sk, bool unmark_loss) { struct tcp_sock *tp = tcp_sk(sk); + if (unmark_loss) { + struct sk_buff *skb; + + tcp_for_write_queue(skb, sk) { + if (skb == tcp_send_head(sk)) + break; + TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST; + } + tp->lost_out = 0; + tcp_clear_all_retrans_hints(tp); + } + if (tp->prior_ssthresh) { const struct inet_connection_sock *icsk = inet_csk(sk); @@ -2319,7 +2258,7 @@ static void tcp_undo_cwr(struct sock *sk, const bool undo_ssthresh) else tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh << 1); - if (undo_ssthresh && tp->prior_ssthresh > tp->snd_ssthresh) { + if (tp->prior_ssthresh > tp->snd_ssthresh) { tp->snd_ssthresh = tp->prior_ssthresh; TCP_ECN_withdraw_cwr(tp); } @@ -2327,6 +2266,7 @@ static void tcp_undo_cwr(struct sock *sk, const bool undo_ssthresh) tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh); } tp->snd_cwnd_stamp = tcp_time_stamp; + tp->undo_marker = 0; } static inline bool tcp_may_undo(const struct tcp_sock *tp) @@ -2346,14 +2286,13 @@ static bool tcp_try_undo_recovery(struct sock *sk) * or our original transmission succeeded. */ DBGUNDO(sk, inet_csk(sk)->icsk_ca_state == TCP_CA_Loss ? "loss" : "retrans"); - tcp_undo_cwr(sk, true); + tcp_undo_cwnd_reduction(sk, false); if (inet_csk(sk)->icsk_ca_state == TCP_CA_Loss) mib_idx = LINUX_MIB_TCPLOSSUNDO; else mib_idx = LINUX_MIB_TCPFULLUNDO; NET_INC_STATS_BH(sock_net(sk), mib_idx); - tp->undo_marker = 0; } if (tp->snd_una == tp->high_seq && tcp_is_reno(tp)) { /* Hold old state until something *above* high_seq @@ -2367,16 +2306,17 @@ static bool tcp_try_undo_recovery(struct sock *sk) } /* Try to undo cwnd reduction, because D-SACKs acked all retransmitted data */ -static void tcp_try_undo_dsack(struct sock *sk) +static bool tcp_try_undo_dsack(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); if (tp->undo_marker && !tp->undo_retrans) { DBGUNDO(sk, "D-SACK"); - tcp_undo_cwr(sk, true); - tp->undo_marker = 0; + tcp_undo_cwnd_reduction(sk, false); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPDSACKUNDO); + return true; } + return false; } /* We can clear retrans_stamp when there are no retransmissions in the @@ -2408,60 +2348,20 @@ static bool tcp_any_retrans_done(const struct sock *sk) return false; } -/* Undo during fast recovery after partial ACK. */ - -static int tcp_try_undo_partial(struct sock *sk, int acked) -{ - struct tcp_sock *tp = tcp_sk(sk); - /* Partial ACK arrived. Force Hoe's retransmit. */ - int failed = tcp_is_reno(tp) || (tcp_fackets_out(tp) > tp->reordering); - - if (tcp_may_undo(tp)) { - /* Plain luck! Hole if filled with delayed - * packet, rather than with a retransmit. - */ - if (!tcp_any_retrans_done(sk)) - tp->retrans_stamp = 0; - - tcp_update_reordering(sk, tcp_fackets_out(tp) + acked, 1); - - DBGUNDO(sk, "Hoe"); - tcp_undo_cwr(sk, false); - NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPPARTIALUNDO); - - /* So... Do not make Hoe's retransmit yet. - * If the first packet was delayed, the rest - * ones are most probably delayed as well. - */ - failed = 0; - } - return failed; -} - /* Undo during loss recovery after partial ACK or using F-RTO. */ static bool tcp_try_undo_loss(struct sock *sk, bool frto_undo) { struct tcp_sock *tp = tcp_sk(sk); if (frto_undo || tcp_may_undo(tp)) { - struct sk_buff *skb; - tcp_for_write_queue(skb, sk) { - if (skb == tcp_send_head(sk)) - break; - TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST; - } - - tcp_clear_all_retrans_hints(tp); + tcp_undo_cwnd_reduction(sk, true); DBGUNDO(sk, "partial loss"); - tp->lost_out = 0; - tcp_undo_cwr(sk, true); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPLOSSUNDO); if (frto_undo) NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSPURIOUSRTOS); inet_csk(sk)->icsk_retransmits = 0; - tp->undo_marker = 0; if (frto_undo || tcp_is_sack(tp)) tcp_set_ca_state(sk, TCP_CA_Open); return true; @@ -2494,12 +2394,14 @@ static void tcp_init_cwnd_reduction(struct sock *sk, const bool set_ssthresh) TCP_ECN_queue_cwr(tp); } -static void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, +static void tcp_cwnd_reduction(struct sock *sk, const int prior_unsacked, int fast_rexmit) { struct tcp_sock *tp = tcp_sk(sk); int sndcnt = 0; int delta = tp->snd_ssthresh - tcp_packets_in_flight(tp); + int newly_acked_sacked = prior_unsacked - + (tp->packets_out - tp->sacked_out); tp->prr_delivered += newly_acked_sacked; if (tcp_packets_in_flight(tp) > tp->snd_ssthresh) { @@ -2556,7 +2458,7 @@ static void tcp_try_keep_open(struct sock *sk) } } -static void tcp_try_to_open(struct sock *sk, int flag, int newly_acked_sacked) +static void tcp_try_to_open(struct sock *sk, int flag, const int prior_unsacked) { struct tcp_sock *tp = tcp_sk(sk); @@ -2573,7 +2475,7 @@ static void tcp_try_to_open(struct sock *sk, int flag, int newly_acked_sacked) if (inet_csk(sk)->icsk_ca_state != TCP_CA_Open) tcp_moderate_cwnd(tp); } else { - tcp_cwnd_reduction(sk, newly_acked_sacked, 0); + tcp_cwnd_reduction(sk, prior_unsacked, 0); } } @@ -2731,6 +2633,40 @@ static void tcp_process_loss(struct sock *sk, int flag, bool is_dupack) tcp_xmit_retransmit_queue(sk); } +/* Undo during fast recovery after partial ACK. */ +static bool tcp_try_undo_partial(struct sock *sk, const int acked, + const int prior_unsacked) +{ + struct tcp_sock *tp = tcp_sk(sk); + + if (tp->undo_marker && tcp_packet_delayed(tp)) { + /* Plain luck! Hole if filled with delayed + * packet, rather than with a retransmit. + */ + tcp_update_reordering(sk, tcp_fackets_out(tp) + acked, 1); + + /* We are getting evidence that the reordering degree is higher + * than we realized. If there are no retransmits out then we + * can undo. Otherwise we clock out new packets but do not + * mark more packets lost or retransmit more. + */ + if (tp->retrans_out) { + tcp_cwnd_reduction(sk, prior_unsacked, 0); + return true; + } + + if (!tcp_any_retrans_done(sk)) + tp->retrans_stamp = 0; + + DBGUNDO(sk, "partial recovery"); + tcp_undo_cwnd_reduction(sk, true); + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPPARTIALUNDO); + tcp_try_keep_open(sk); + return true; + } + return false; +} + /* Process an event, which can update packets-in-flight not trivially. * Main goal of this function is to calculate new estimate for left_out, * taking into account both packets sitting in receiver's buffer and @@ -2742,15 +2678,14 @@ static void tcp_process_loss(struct sock *sk, int flag, bool is_dupack) * It does _not_ decide what to send, it is made in function * tcp_xmit_retransmit_queue(). */ -static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, - int prior_sacked, int prior_packets, +static void tcp_fastretrans_alert(struct sock *sk, const int acked, + const int prior_unsacked, 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) && + bool 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)) @@ -2802,10 +2737,17 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, if (!(flag & FLAG_SND_UNA_ADVANCED)) { if (tcp_is_reno(tp) && is_dupack) tcp_add_reno_sack(sk); - } else - do_lost = tcp_try_undo_partial(sk, pkts_acked); - newly_acked_sacked = prior_packets - tp->packets_out + - tp->sacked_out - prior_sacked; + } else { + if (tcp_try_undo_partial(sk, acked, prior_unsacked)) + return; + /* Partial ACK arrived. Force fast retransmit. */ + do_lost = tcp_is_reno(tp) || + tcp_fackets_out(tp) > tp->reordering; + } + if (tcp_try_undo_dsack(sk)) { + tcp_try_keep_open(sk); + return; + } break; case TCP_CA_Loss: tcp_process_loss(sk, flag, is_dupack); @@ -2819,14 +2761,12 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, if (is_dupack) tcp_add_reno_sack(sk); } - newly_acked_sacked = prior_packets - tp->packets_out + - 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, newly_acked_sacked); + tcp_try_to_open(sk, flag, prior_unsacked); return; } @@ -2846,9 +2786,9 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, fast_rexmit = 1; } - if (do_lost || (tcp_is_fack(tp) && tcp_head_timedout(sk))) + if (do_lost) tcp_update_scoreboard(sk, fast_rexmit); - tcp_cwnd_reduction(sk, newly_acked_sacked, fast_rexmit); + tcp_cwnd_reduction(sk, prior_unsacked, fast_rexmit); tcp_xmit_retransmit_queue(sk); } @@ -3079,7 +3019,6 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets, tcp_unlink_write_queue(skb, sk); sk_wmem_free_skb(sk, skb); - tp->scoreboard_skb_hint = NULL; if (skb == tp->retransmit_skb_hint) tp->retransmit_skb_hint = NULL; if (skb == tp->lost_skb_hint) @@ -3333,9 +3272,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) u32 prior_in_flight; u32 prior_fackets; int prior_packets = tp->packets_out; - int prior_sacked = tp->sacked_out; - int pkts_acked = 0; - int previous_packets_out = 0; + const int prior_unsacked = tp->packets_out - tp->sacked_out; + int acked = 0; /* Number of packets newly acked */ /* If the ack is older than previous acks * then we can probably ignore it. @@ -3410,18 +3348,17 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) goto no_queue; /* See if we can take anything off of the retransmit queue. */ - previous_packets_out = tp->packets_out; + acked = tp->packets_out; flag |= tcp_clean_rtx_queue(sk, prior_fackets, prior_snd_una); - - pkts_acked = previous_packets_out - tp->packets_out; + acked -= tp->packets_out; if (tcp_ack_is_dubious(sk, flag)) { /* Advance CWND, if state allows this. */ if ((flag & FLAG_DATA_ACKED) && 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, prior_sacked, - prior_packets, is_dupack, flag); + tcp_fastretrans_alert(sk, acked, prior_unsacked, + is_dupack, flag); } else { if (flag & FLAG_DATA_ACKED) tcp_cong_avoid(sk, ack, prior_in_flight); @@ -3443,8 +3380,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) 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, prior_sacked, - prior_packets, is_dupack, flag); + tcp_fastretrans_alert(sk, acked, prior_unsacked, + 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 * it needs to be for normal retransmission. @@ -3466,8 +3403,8 @@ old_ack: */ if (TCP_SKB_CB(skb)->sacked) { flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una); - tcp_fastretrans_alert(sk, pkts_acked, prior_sacked, - prior_packets, is_dupack, flag); + tcp_fastretrans_alert(sk, acked, prior_unsacked, + is_dupack, flag); } SOCK_DEBUG(sk, "Ack %u before %u:%u\n", ack, tp->snd_una, tp->snd_nxt); @@ -3780,6 +3717,7 @@ void tcp_reset(struct sock *sk) static void tcp_fin(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); + const struct dst_entry *dst; inet_csk_schedule_ack(sk); @@ -3791,7 +3729,9 @@ static void tcp_fin(struct sock *sk) case TCP_ESTABLISHED: /* Move to CLOSE_WAIT */ tcp_set_state(sk, TCP_CLOSE_WAIT); - inet_csk(sk)->icsk_ack.pingpong = 1; + dst = __sk_dst_get(sk); + if (!dst || !dst_metric(dst, RTAX_QUICKACK)) + inet_csk(sk)->icsk_ack.pingpong = 1; break; case TCP_CLOSE_WAIT: @@ -5601,6 +5541,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, struct inet_connection_sock *icsk = inet_csk(sk); struct request_sock *req; int queued = 0; + bool acceptable; tp->rx_opt.saw_tstamp = 0; @@ -5671,157 +5612,147 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, return 0; /* step 5: check the ACK field */ - if (true) { - int acceptable = tcp_ack(sk, skb, FLAG_SLOWPATH | - FLAG_UPDATE_TS_RECENT) > 0; - - switch (sk->sk_state) { - case TCP_SYN_RECV: - if (acceptable) { - /* 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->num_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); + acceptable = tcp_ack(sk, skb, FLAG_SLOWPATH | + FLAG_UPDATE_TS_RECENT) > 0; - 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); - - /* Note, that this wakeup is only for marginal - * crossed SYN case. Passively open sockets - * are not waked up, because sk->sk_sleep == - * NULL and sk->sk_socket == NULL. - */ - if (sk->sk_socket) - sk_wake_async(sk, - SOCK_WAKE_IO, POLL_OUT); - - tp->snd_una = TCP_SKB_CB(skb)->ack_seq; - tp->snd_wnd = ntohs(th->window) << - tp->rx_opt.snd_wscale; - tcp_init_wl(tp, TCP_SKB_CB(skb)->seq); - - if (tp->rx_opt.tstamp_ok) - tp->advmss -= TCPOLEN_TSTAMP_ALIGNED; - - 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); + switch (sk->sk_state) { + case TCP_SYN_RECV: + if (!acceptable) + return 1; - /* Prevent spurious tcp_cwnd_restart() on - * first data packet. - */ - tp->lsndtime = tcp_time_stamp; + /* 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->num_retrans; - tcp_initialize_rcv_mss(sk); - tcp_fast_path_on(tp); - } else { - return 1; - } - break; + 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); + + /* Note, that this wakeup is only for marginal crossed SYN case. + * Passively open sockets are not waked up, because + * sk->sk_sleep == NULL and sk->sk_socket == NULL. + */ + if (sk->sk_socket) + sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); + + tp->snd_una = TCP_SKB_CB(skb)->ack_seq; + tp->snd_wnd = ntohs(th->window) << tp->rx_opt.snd_wscale; + tcp_init_wl(tp, TCP_SKB_CB(skb)->seq); - 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 (tp->rx_opt.tstamp_ok) + tp->advmss -= TCPOLEN_TSTAMP_ALIGNED; + + 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 + * retransmitting any data sooner based on when they + * are sent out. */ - if (req != NULL) { - /* Return RST if ack_seq is invalid. - * Note that RFC793 only says to generate a - * DUPACK for it but for TCP Fast Open it seems - * better to treat this case like TCP_SYN_RECV - * above. - */ - if (!acceptable) - return 1; - /* 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 = __sk_dst_get(sk); - if (dst) - dst_confirm(dst); - - if (!sock_flag(sk, SOCK_DEAD)) - /* Wake up lingering close() */ - sk->sk_state_change(sk); - else { - int tmo; - - if (tp->linger2 < 0 || - (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq && - after(TCP_SKB_CB(skb)->end_seq - th->fin, tp->rcv_nxt))) { - tcp_done(sk); - NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONDATA); - return 1; - } + tcp_rearm_rto(sk); + } else + tcp_init_metrics(sk); - tmo = tcp_fin_time(sk); - if (tmo > TCP_TIMEWAIT_LEN) { - inet_csk_reset_keepalive_timer(sk, tmo - TCP_TIMEWAIT_LEN); - } else if (th->fin || sock_owned_by_user(sk)) { - /* Bad case. We could lose such FIN otherwise. - * It is not a big problem, but it looks confusing - * and not so rare event. We still can lose it now, - * if it spins in bh_lock_sock(), but it is really - * marginal case. - */ - inet_csk_reset_keepalive_timer(sk, tmo); - } else { - tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); - goto discard; - } - } - } - break; + /* Prevent spurious tcp_cwnd_restart() on first data packet */ + tp->lsndtime = tcp_time_stamp; - case TCP_CLOSING: - if (tp->snd_una == tp->write_seq) { - tcp_time_wait(sk, TCP_TIME_WAIT, 0); - goto discard; - } + tcp_initialize_rcv_mss(sk); + tcp_fast_path_on(tp); + break; + + case TCP_FIN_WAIT1: { + struct dst_entry *dst; + int tmo; + + /* 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 (req != NULL) { + /* Return RST if ack_seq is invalid. + * Note that RFC793 only says to generate a + * DUPACK for it but for TCP Fast Open it seems + * better to treat this case like TCP_SYN_RECV + * above. + */ + if (!acceptable) + return 1; + /* We no longer need the request sock. */ + reqsk_fastopen_remove(sk, req, false); + tcp_rearm_rto(sk); + } + if (tp->snd_una != tp->write_seq) break; - case TCP_LAST_ACK: - if (tp->snd_una == tp->write_seq) { - tcp_update_metrics(sk); - tcp_done(sk); - goto discard; - } + tcp_set_state(sk, TCP_FIN_WAIT2); + sk->sk_shutdown |= SEND_SHUTDOWN; + + dst = __sk_dst_get(sk); + if (dst) + dst_confirm(dst); + + if (!sock_flag(sk, SOCK_DEAD)) { + /* Wake up lingering close() */ + sk->sk_state_change(sk); break; } + + if (tp->linger2 < 0 || + (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq && + after(TCP_SKB_CB(skb)->end_seq - th->fin, tp->rcv_nxt))) { + tcp_done(sk); + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONDATA); + return 1; + } + + tmo = tcp_fin_time(sk); + if (tmo > TCP_TIMEWAIT_LEN) { + inet_csk_reset_keepalive_timer(sk, tmo - TCP_TIMEWAIT_LEN); + } else if (th->fin || sock_owned_by_user(sk)) { + /* Bad case. We could lose such FIN otherwise. + * It is not a big problem, but it looks confusing + * and not so rare event. We still can lose it now, + * if it spins in bh_lock_sock(), but it is really + * marginal case. + */ + inet_csk_reset_keepalive_timer(sk, tmo); + } else { + tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); + goto discard; + } + break; + } + + case TCP_CLOSING: + if (tp->snd_una == tp->write_seq) { + tcp_time_wait(sk, TCP_TIME_WAIT, 0); + goto discard; + } + break; + + case TCP_LAST_ACK: + if (tp->snd_una == tp->write_seq) { + tcp_update_metrics(sk); + tcp_done(sk); + goto discard; + } + break; } /* step 6: check the URG bit */ |