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[TCP] FRTO: Separated response from FRTO detection algorithm

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FRTO spurious RTO detection algorithm (RFC4138) does not include response
to a detected spurious RTO but can use different response algorithms.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ilpo Järvinen 2007-02-21 22:56:19 -08:00 • committed by David S. Miller
parent 522e7548a9
commit 9ead9a1d38
1 changed files with 10 additions and 6 deletions
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16
net/ipv4/tcp_input.c
View file

@ -2467,6 +2467,15 @@ static int tcp_ack_update_window(struct sock *sk, struct tcp_sock *tp,
return flag; return flag;
} }
/* A very conservative spurious RTO response algorithm: reduce cwnd and
* continue in congestion avoidance.
*/
static void tcp_conservative_spur_to_response(struct tcp_sock *tp)
{
tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);
tcp_moderate_cwnd(tp);
}
static void tcp_process_frto(struct sock *sk, u32 prior_snd_una) static void tcp_process_frto(struct sock *sk, u32 prior_snd_una)
{ {
struct tcp_sock *tp = tcp_sk(sk); struct tcp_sock *tp = tcp_sk(sk);
@ -2488,12 +2497,7 @@ static void tcp_process_frto(struct sock *sk, u32 prior_snd_una)
*/ */
tp->snd_cwnd = tcp_packets_in_flight(tp) + 2; tp->snd_cwnd = tcp_packets_in_flight(tp) + 2;
} else { } else {
/* Also the second ACK after RTO advances the window. tcp_conservative_spur_to_response(tp);
* The RTO was likely spurious. Reduce cwnd and continue
* in congestion avoidance
*/
tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);
tcp_moderate_cwnd(tp);
} }
/* F-RTO affects on two new ACKs following RTO. /* F-RTO affects on two new ACKs following RTO.