Date: Thu, 17 Dec 2009 11:28:36 -0800 From: "Li, Qing" <qing.li@bluecoat.com> To: =?gb2312?B?zfW0urfn?= <fengdreamer@126.com>, "freebsd-net" <freebsd-net@freebsd.org> Subject: RE: Bug discussion:Tcp snd_nxt will not be increased. Message-ID: <B583FBF374231F4A89607B4D08578A4306236179@bcs-mail03.internal.cacheflow.com> In-Reply-To: <31264189.456321261063444556.JavaMail.coremail@bj126app49.126.com> References: <31264189.456321261063444556.JavaMail.coremail@bj126app49.126.com>
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Hi, Could you please tell us what version you are running? > > If the tcp_output just have some error, for example: when alloc mbuf, > it returns NULL, and then the snd_nxt number will not be return to > normal. > If just in this time, SYN Ack arrives, freeBSD can't handle this > situdition. > I have seen a related issue in older versions that I fixed, but it's = from=20 the SYN+ACK perspective. If my memory serves me right, local listener = receives a SYN packet, transmits the SYN+ACK, but memory allocation fails, so the SYN+ACK packet was never transmitted onto the wire, however, the SEQ = advanced by 1. As a result of SEQ update, the retransmitted SYN packet from the = other=20 end were discard as duplicates, eventually the connection times out. -- Qing
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