diff options
Diffstat (limited to 'net/ipv4/tcp_input.c')
| -rw-r--r-- | net/ipv4/tcp_input.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 6b669898b197..7641b2761a14 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2637,7 +2637,9 @@ static void tcp_undo_spur_to_response(struct sock *sk, int flag) * algorithm is not part of the F-RTO detection algorithm * given in RFC4138 but can be selected separately). * Otherwise (basically on duplicate ACK), RTO was (likely) caused by a loss - * and TCP falls back to conventional RTO recovery. + * and TCP falls back to conventional RTO recovery. F-RTO allows overriding + * of Nagle, this is done using frto_counter states 2 and 3, when a new data + * segment of any size sent during F-RTO, state 2 is upgraded to 3. * * Rationale: if the RTO was spurious, new ACKs should arrive from the * original window even after we transmit two new data segments. @@ -2666,7 +2668,7 @@ static int tcp_process_frto(struct sock *sk, u32 prior_snd_una, int flag) inet_csk(sk)->icsk_retransmits = 0; if (!before(tp->snd_una, tp->frto_highmark)) { - tcp_enter_frto_loss(sk, tp->frto_counter + 1, flag); + tcp_enter_frto_loss(sk, (tp->frto_counter == 1 ? 2 : 3), flag); return 1; } @@ -2692,7 +2694,7 @@ static int tcp_process_frto(struct sock *sk, u32 prior_snd_una, int flag) return 1; } - if ((tp->frto_counter == 2) && + if ((tp->frto_counter >= 2) && (!(flag&FLAG_FORWARD_PROGRESS) || ((flag&FLAG_DATA_SACKED) && !(flag&FLAG_ONLY_ORIG_SACKED)))) { /* RFC4138 shortcoming (see comment above) */ @@ -2709,14 +2711,15 @@ static int tcp_process_frto(struct sock *sk, u32 prior_snd_una, int flag) if (!tcp_send_head(sk) || after(TCP_SKB_CB(tcp_send_head(sk))->end_seq, tp->snd_una + tp->snd_wnd)) { - tcp_enter_frto_loss(sk, tp->frto_counter + 1, flag); + tcp_enter_frto_loss(sk, (tp->frto_counter == 1 ? 2 : 3), + flag); return 1; } tp->snd_cwnd = tcp_packets_in_flight(tp) + 2; tp->frto_counter = 2; return 1; - } else /* frto_counter == 2 */ { + } else { switch (sysctl_tcp_frto_response) { case 2: tcp_undo_spur_to_response(sk, flag); |