From 7c9a4a5b67926dd186d427bc5b9fce6ccbde154c Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Wed, 21 Feb 2007 23:08:34 -0800 Subject: [PATCH] [TCP]: Prevent unrelated cwnd adjustment while using FRTO MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit FRTO controls cwnd when it still processes the ACK input or it has just reverted back to conventional RTO recovery; the normal rules apply when FRTO has reverted to standard congestion control. Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 9dc5754141e..723cee63791 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2522,7 +2522,7 @@ static void tcp_conservative_spur_to_response(struct tcp_sock *tp) * to prove that the RTO is indeed spurious. It transfers the control * from F-RTO to the conventional RTO recovery */ -static void tcp_process_frto(struct sock *sk, u32 prior_snd_una, int flag) +static int tcp_process_frto(struct sock *sk, u32 prior_snd_una, int flag) { struct tcp_sock *tp = tcp_sk(sk); @@ -2534,7 +2534,7 @@ static void tcp_process_frto(struct sock *sk, u32 prior_snd_una, int flag) if (!before(tp->snd_una, tp->frto_highmark)) { tcp_enter_frto_loss(sk, tp->frto_counter + 1); - return; + return 1; } /* RFC4138 shortcoming in step 2; should also have case c): ACK isn't @@ -2542,20 +2542,22 @@ static void tcp_process_frto(struct sock *sk, u32 prior_snd_una, int flag) */ if ((tp->snd_una == prior_snd_una) && (flag&FLAG_NOT_DUP) && !(flag&FLAG_FORWARD_PROGRESS)) - return; + return 1; if (!(flag&FLAG_DATA_ACKED)) { tcp_enter_frto_loss(sk, (tp->frto_counter == 1 ? 0 : 3)); - return; + return 1; } if (tp->frto_counter == 1) { tp->snd_cwnd = tcp_packets_in_flight(tp) + 2; tp->frto_counter = 2; + return 1; } else /* frto_counter == 2 */ { tcp_conservative_spur_to_response(tp); tp->frto_counter = 0; } + return 0; } /* This routine deals with incoming acks, but not outgoing ones. */ @@ -2569,6 +2571,7 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag) u32 prior_in_flight; s32 seq_rtt; int prior_packets; + int frto_cwnd = 0; /* If the ack is newer than sent or older than previous acks * then we can probably ignore it. @@ -2631,15 +2634,16 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag) flag |= tcp_clean_rtx_queue(sk, &seq_rtt); if (tp->frto_counter) - tcp_process_frto(sk, prior_snd_una, flag); + frto_cwnd = tcp_process_frto(sk, prior_snd_una, flag); if (tcp_ack_is_dubious(sk, flag)) { /* Advance CWND, if state allows this. */ - if ((flag & FLAG_DATA_ACKED) && tcp_may_raise_cwnd(sk, flag)) + if ((flag & FLAG_DATA_ACKED) && !frto_cwnd && + tcp_may_raise_cwnd(sk, flag)) tcp_cong_avoid(sk, ack, seq_rtt, prior_in_flight, 0); tcp_fastretrans_alert(sk, prior_snd_una, prior_packets, flag); } else { - if ((flag & FLAG_DATA_ACKED)) + if ((flag & FLAG_DATA_ACKED) && !frto_cwnd) tcp_cong_avoid(sk, ack, seq_rtt, prior_in_flight, 1); } -- 2.46.0