Date: Mon, 13 Jan 2025 18:15:23 GMT From: Gleb Smirnoff <glebius@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 1043b36b2054 - main - tcp: don't send beyond receivers advertised window Message-ID: <202501131815.50DIFNIt008136@gitrepo.freebsd.org>
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The branch main has been updated by glebius: URL: https://cgit.FreeBSD.org/src/commit/?id=1043b36b2054ffb32aadfe1c276684bf463db59a commit 1043b36b2054ffb32aadfe1c276684bf463db59a Author: Gleb Smirnoff <glebius@FreeBSD.org> AuthorDate: 2025-01-13 18:13:54 +0000 Commit: Gleb Smirnoff <glebius@FreeBSD.org> CommitDate: 2025-01-13 18:13:54 +0000 tcp: don't send beyond receivers advertised window When calculating length of data to be sent, we may do some congestion calculations, but we shall never send a byte beyond (snd_una + snd_wnd). In 7dc78150c730e we started to use tcp_compute_pipe() instead of (snd_wnd - off). This function makes an estimate of how much data is in flight. It can return a value smaller and larger than (snd_nxt - snd_una). It will return a value larger when we have retransmitted some data from SACK holes, and smaller once those retransmitted SACK holes are acked. We may use tcp_compute_pipe() for length calculation, but always capped by the send offset 'off', which (snd_nxt - snd_una). PR: 283649 Reviewed by: rscheff Differential Revision: https://reviews.freebsd.org/D48237 Fixes: 7dc78150c730e90fa2afdaba3aa645932b30c429 --- sys/netinet/tcp_output.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c index 74a229012508..135e7d8493e2 100644 --- a/sys/netinet/tcp_output.c +++ b/sys/netinet/tcp_output.c @@ -421,8 +421,9 @@ after_sack_rexmit: * sending new data, having retransmitted all the * data possible in the scoreboard. */ - len = imin(sbavail(&so->so_snd) - off, - sendwin - tcp_compute_pipe(tp)); + len = imax( + imin(sbavail(&so->so_snd), sendwin) - + imax(tcp_compute_pipe(tp), off), 0); } }
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