tcp: Perform simple fast retransmit when SACK Blocks are missing on SACK session

MFC after: 2 weeks
Reviewed By: #transport, rrs
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D28634
This commit is contained in:
Richard Scheffenegger 2021-03-25 23:18:06 +01:00
parent 653a437c04
commit 0533fab89e

View File

@ -2564,6 +2564,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
*/
if (th->th_ack != tp->snd_una ||
((tp->t_flags & TF_SACK_PERMIT) &&
(to.to_flags & TOF_SACK) &&
!sack_changed))
break;
else if (!tcp_timer_active(tp, TT_REXMT))
@ -2617,6 +2618,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
tp->snd_cwnd = imax(maxseg, tp->snd_nxt - tp->snd_recover +
tp->sackhint.sack_bytes_rexmit + (snd_cnt * maxseg));
} else if ((tp->t_flags & TF_SACK_PERMIT) &&
(to.to_flags & TOF_SACK) &&
IN_FASTRECOVERY(tp->t_flags)) {
int awnd;
@ -2694,7 +2696,8 @@ enter_recovery:
tp->sackhint.recover_fs = max(1,
tp->snd_nxt - tp->snd_una);
}
if (tp->t_flags & TF_SACK_PERMIT) {
if ((tp->t_flags & TF_SACK_PERMIT) &&
(to.to_flags & TOF_SACK)) {
TCPSTAT_INC(
tcps_sack_recovery_episode);
tp->snd_recover = tp->snd_nxt;