From d76eb0da7283f83b09d5491d81e25485d87298ab Mon Sep 17 00:00:00 2001 From: Richard Scheffenegger Date: Sun, 18 Apr 2021 22:14:14 +0200 Subject: tcp: keep SACK scoreboard sorted when doing rescue retransmission Reviewed By: tuexen, kbowling, #transport MFC after: 3 days Sponsored by: NetApp, Inc. Differential Revision: https://reviews.freebsd.org/D29825 (cherry picked from commit b87cf2bc841b2a336b7f0c6cd89573610412a84f) --- sys/netinet/tcp_sack.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/sys/netinet/tcp_sack.c b/sys/netinet/tcp_sack.c index f8d983da723b..08ce2a0882b1 100644 --- a/sys/netinet/tcp_sack.c +++ b/sys/netinet/tcp_sack.c @@ -491,7 +491,7 @@ static struct sackhole * tcp_sackhole_insert(struct tcpcb *tp, tcp_seq start, tcp_seq end, struct sackhole *after) { - struct sackhole *hole; + struct sackhole *hole, *tail; /* Allocate a new SACK hole. */ hole = tcp_sackhole_alloc(tp, start, end); @@ -502,7 +502,15 @@ tcp_sackhole_insert(struct tcpcb *tp, tcp_seq start, tcp_seq end, if (after != NULL) TAILQ_INSERT_AFTER(&tp->snd_holes, after, hole, scblink); else - TAILQ_INSERT_TAIL(&tp->snd_holes, hole, scblink); + /* + * With Rescue Retransmission, new holes may need to + * be inserted just before the tail. + */ + if (((tail = TAILQ_LAST_FAST(&tp->snd_holes, sackhole, + scblink)) != NULL) && SEQ_LEQ(end, tail->start)) + TAILQ_INSERT_BEFORE(tail, hole, scblink); + else + TAILQ_INSERT_TAIL(&tp->snd_holes, hole, scblink); /* Update SACK hint. */ if (tp->sackhint.nexthole == NULL) -- cgit v1.2.3