The branch main has been updated by rscheff:
URL:
https://cgit.FreeBSD.org/src/commit/?id=65d4a83399843cb4c6dd44061599390843c162db
commit 65d4a83399843cb4c6dd44061599390843c162db
Author: Richard Scheffenegger <rsch...@freebsd.org>
AuthorDate: 2025-08-06 20:25:30 +0000
Commit: Richard Scheffenegger <rsch...@freebsd.org>
CommitDate: 2025-08-06 21:47:05 +0000
tcp: ensure SACK rxmit never ends up left of its hole
When a RTO happens during SACK loss recovery, snd_recover can possibly
pulled left.
With Lost Retransmission Detection (LRD) this can lead to rxmit of a hole
to end up
pointing to the left of the hole, which is unexpected and leads to
complications.
Reviewed By: tuexen, #transport
Sponsored by: NetApp, Inc.
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D51725
---
sys/netinet/tcp_output.c | 2 +-
sys/netinet/tcp_sack.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
index bc5b42ee6f2c..2dfb7faf56e3 100644
--- a/sys/netinet/tcp_output.c
+++ b/sys/netinet/tcp_output.c
@@ -1250,7 +1250,7 @@ send:
* fack acks recoverypoint.
*/
if ((tp->t_flags & TF_LRD) && SEQ_GEQ(p->rxmit, p->end))
- p->rxmit = tp->snd_recover;
+ p->rxmit = SEQ_MAX(p->rxmit, tp->snd_recover);
tp->sackhint.sack_bytes_rexmit += len;
}
if (IN_RECOVERY(tp->t_flags)) {
diff --git a/sys/netinet/tcp_sack.c b/sys/netinet/tcp_sack.c
index 66275cb04bdd..b6c55fac50b3 100644
--- a/sys/netinet/tcp_sack.c
+++ b/sys/netinet/tcp_sack.c
@@ -816,7 +816,7 @@ tcp_sack_doack(struct tcpcb *tp, struct tcpopt *to, tcp_seq
th_ack)
cur->end = sblkp->start;
cur->rxmit = SEQ_MIN(cur->rxmit, cur->end);
if ((tp->t_flags & TF_LRD) &&
SEQ_GEQ(cur->rxmit, cur->end))
- cur->rxmit = tp->snd_recover;
+ cur->rxmit = SEQ_MAX(cur->rxmit,
tp->snd_recover);
} else {
/*
* ACKs some data in middle of a hole; need
@@ -843,7 +843,7 @@ tcp_sack_doack(struct tcpcb *tp, struct tcpopt *to, tcp_seq
th_ack)
cur->rxmit = SEQ_MIN(cur->rxmit,
cur->end);
if ((tp->t_flags & TF_LRD) &&
SEQ_GEQ(cur->rxmit, cur->end))
- cur->rxmit = tp->snd_recover;
+ cur->rxmit =
SEQ_MAX(cur->rxmit, tp->snd_recover);
delivered_data += (sblkp->end -
sblkp->start);
}
}
