diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 8230cd6243aa83e819c8b59cd4fc58cb0754aae7..40614257d2c5d2246e175596661169ae941e1a0d 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5536,6 +5536,7 @@ 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; @@ -5606,157 +5607,153 @@ 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); + 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; - /* 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. + reqsk_fastopen_remove(sk, req, false); + } else { + /* Make sure socket is routed, for + * correct metrics. */ - 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); + icsk->icsk_af_ops->rebuild_header(sk); + tcp_init_congestion_control(sk); - /* Prevent spurious tcp_cwnd_restart() on - * first data packet. + 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 retransmitting any data sooner based + * on when they are sent out. */ - tp->lsndtime = tcp_time_stamp; + tcp_rearm_rto(sk); + } else + tcp_init_metrics(sk); - tcp_initialize_rcv_mss(sk); - tcp_fast_path_on(tp); - } else { - return 1; - } - break; + /* Prevent spurious tcp_cwnd_restart() on + * first data packet. + */ + tp->lsndtime = tcp_time_stamp; - 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. + tcp_initialize_rcv_mss(sk); + tcp_fast_path_on(tp); + } else { + return 1; + } + 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 (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 (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) + 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; - /* 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; - } + } - 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; - } + 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; + } + break; - case TCP_CLOSING: - if (tp->snd_una == tp->write_seq) { - tcp_time_wait(sk, TCP_TIME_WAIT, 0); - 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; + 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 */