Date: Fri, 13 May 2016 10:36:33 -0700 From: hiren panchasara <hiren@strugglingcoder.info> To: transport@FreeBSD.org Subject: Abrupt reset sent instead of retransmitting a lost packet Message-ID: <20160513173633.GG44085@strugglingcoder.info>
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--64j1qyTOoGvYcHb1 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable https://people.freebsd.org/~hiren/pcaps/tcp_weird_reset.txt Something we saw in the wild on 10.2ish systems (server and client both). The most interesting thing can be seen at the end of the file. 3298737767:3298739215 gets lost, client tells us about it via a bunch of dupacks with SACK info. It SACKs all the outstanding data but this one missing packet. We (server) never retransmits that missing packet but rather decide to send a Reset after 0.312582ms. Which somehow causes client to pause for 75secs. (which might be another issue and not particularly important for this discussion.) What could cause this behavior of sending a reset instead of retransmitting a lost packet?=20 Cheers, Hiren --64j1qyTOoGvYcHb1 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQF8BAABCgBmBQJXNhCZXxSAAAAAAC4AKGlzc3Vlci1mcHJAbm90YXRpb25zLm9w ZW5wZ3AuZmlmdGhob3JzZW1hbi5uZXRBNEUyMEZBMUQ4Nzg4RjNGMTdFNjZGMDI4 QjkyNTBFMTU2M0VERkU1AAoJEIuSUOFWPt/ll9wH/jMku5AsfNer9G+owLpgIbIy +8z+A2csNJELmOd497IQfkkTvCtRO3xnzxFeV8uMer7ju+KiGX1xhVzEsEoQcyI1 y0qNel0zzhnnuUWisivBCnxA+rNhKRVd/tW7Vd3sX83Xjz9PaJZEvZqfwU8dTjsW fHN8ORU2b9eo5JL7SN/D5vknspFbkPdIOnDtKbQ0hODHuOW/Z1/D69R63h4aGikC Fm0eQRux41aQQ//eBQncm1BIQ4hJGb/1bzC8TgQxl7Xhd15WPv8WpMNGizUPVIj0 DI7JEuJnYYcs2bBvz+UFZ5tw+L7Zx+tOpvFg7dtJJEfkbx/P6aEdiTGj18cpZlQ= =lH+D -----END PGP SIGNATURE----- --64j1qyTOoGvYcHb1--
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