Date: Sun, 25 Sep 2022 10:05:21 GMT From: Richard Scheffenegger <rscheff@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: c1f9a81e7bfe - stable/13 - tcp: fix cwnd restricted SACK retransmission loop Message-ID: <202209251005.28PA5L5k047531@gitrepo.freebsd.org>
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The branch stable/13 has been updated by rscheff: URL: https://cgit.FreeBSD.org/src/commit/?id=c1f9a81e7bfe354dfa4f191d5180426f76bc514b commit c1f9a81e7bfe354dfa4f191d5180426f76bc514b Author: Richard Scheffenegger <rscheff@FreeBSD.org> AuthorDate: 2022-09-22 10:55:25 +0000 Commit: Richard Scheffenegger <rscheff@FreeBSD.org> CommitDate: 2022-09-25 08:56:28 +0000 tcp: fix cwnd restricted SACK retransmission loop While doing the initial SACK retransmission segment while heavily cwnd constrained, tcp_ouput can erroneously send out the entire sendbuffer again. This may happen after an retransmission timeout, which resets snd_nxt to snd_una while the SACK scoreboard is still populated. Reviewed By: tuexen, #transport PR: 264257 PR: 263445 PR: 260393 MFC after: 3 days Sponsored by: NetApp, Inc. Differential Revision: https://reviews.freebsd.org/D36637 (cherry picked from commit a743fc8826fa348b09d219632594c537f8e5690e) --- sys/netinet/tcp_output.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c index 01dca2ba3ea1..a30f8eab389d 100644 --- a/sys/netinet/tcp_output.c +++ b/sys/netinet/tcp_output.c @@ -411,7 +411,7 @@ after_sack_rexmit: else { int32_t cwin; - /* + /* * We are inside of a SACK recovery episode and are * sending new data, having retransmitted all the * data possible in the scoreboard. @@ -427,8 +427,8 @@ after_sack_rexmit: * of len is bungled by the optimizer. */ if (len > 0) { - cwin = tp->snd_cwnd - - (tp->snd_nxt - tp->snd_recover) - + cwin = tp->snd_cwnd - imax(0, (int32_t) + (tp->snd_nxt - tp->snd_recover)) - sack_bytes_rxmt; if (cwin < 0) cwin = 0;
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