diff options
| -rw-r--r-- | net/ipv4/tcp_input.c | 35 |
1 files changed, 32 insertions, 3 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 57ae96a04220..12cab7d74dba 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2717,6 +2717,35 @@ static void tcp_try_undo_dsack(struct sock *sk) } } +/* We can clear retrans_stamp when there are no retransmissions in the + * window. It would seem that it is trivially available for us in + * tp->retrans_out, however, that kind of assumptions doesn't consider + * what will happen if errors occur when sending retransmission for the + * second time. ...It could the that such segment has only + * TCPCB_EVER_RETRANS set at the present time. It seems that checking + * the head skb is enough except for some reneging corner cases that + * are not worth the effort. + * + * Main reason for all this complexity is the fact that connection dying + * time now depends on the validity of the retrans_stamp, in particular, + * that successive retransmissions of a segment must not advance + * retrans_stamp under any conditions. + */ +static int tcp_any_retrans_done(struct sock *sk) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct sk_buff *skb; + + if (tp->retrans_out) + return 1; + + skb = tcp_write_queue_head(sk); + if (unlikely(skb && TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS)) + return 1; + + return 0; +} + /* Undo during fast recovery after partial ACK. */ static int tcp_try_undo_partial(struct sock *sk, int acked) @@ -2729,7 +2758,7 @@ static int tcp_try_undo_partial(struct sock *sk, int acked) /* Plain luck! Hole if filled with delayed * packet, rather than with a retransmit. */ - if (tp->retrans_out == 0) + if (!tcp_any_retrans_done(sk)) tp->retrans_stamp = 0; tcp_update_reordering(sk, tcp_fackets_out(tp) + acked, 1); @@ -2788,7 +2817,7 @@ static void tcp_try_keep_open(struct sock *sk) struct tcp_sock *tp = tcp_sk(sk); int state = TCP_CA_Open; - if (tcp_left_out(tp) || tp->retrans_out || tp->undo_marker) + if (tcp_left_out(tp) || tcp_any_retrans_done(sk) || tp->undo_marker) state = TCP_CA_Disorder; if (inet_csk(sk)->icsk_ca_state != state) { @@ -2803,7 +2832,7 @@ static void tcp_try_to_open(struct sock *sk, int flag) tcp_verify_left_out(tp); - if (!tp->frto_counter && tp->retrans_out == 0) + if (!tp->frto_counter && !tcp_any_retrans_done(sk)) tp->retrans_stamp = 0; if (flag & FLAG_ECE) |