Date: Wed, 18 Jul 2007 12:12:15 -0700 From: Julian Elischer <julian@ironport.com> To: Eygene Ryabinkin <rea-fbsd@codelabs.ru> Cc: FreeBSD Net <freebsd-net@freebsd.org>, Julian Elischer <julian@elischer.org> Subject: Re: Wierd networking. Message-ID: <469E660F.8000109@ironport.com> In-Reply-To: <20070718055228.GA4053@void.codelabs.ru> References: <469D4C9D.7090302@ironport.com> <469D4FB6.9040609@elischer.org> <3DBBD4E3-ABEA-451A-8E6A-02E9CBAD6A37@mac.com> <20070718055228.GA4053@void.codelabs.ru>
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This is a multi-part message in MIME format. --------------070601040006030604020807 Content-Type: text/plain; charset=KOI8-R; format=flowed Content-Transfer-Encoding: 7bit Eygene Ryabinkin wrote: > Chuck, Julian, good day. > > Tue, Jul 17, 2007 at 04:47:30PM -0700, Chuck Swiger wrote: > >> % tcpdump -nS -r IE7.pcap >> reading from file IE7.pcap, link-type EN10MB (Ethernet) >> 18:24:41.313890 IP 172.28.15.82.3128 > 10.251.22.29.1121: . ack 1573162290 win >> 32120 >> 18:24:41.313995 IP 10.251.22.29.1121 > 172.28.15.82.3128: P >> 1573162290:1573162378(88) ack 3799409121 win 65535 >> 18:24:41.314015 IP 172.28.15.82.3128 > 10.251.22.29.1121: . ack 1573162378 win >> 33492 >> 18:24:41.314072 IP 172.28.15.82.3128 > 10.251.22.29.1121: . >> 3799409121:3799410581(1460) ack 1573162378 win 33580 >> 18:24:41.314080 IP 172.28.15.82.3128 > 10.251.22.29.1121: P >> 3799410581:3799410861(280) ack 1573162378 win 33580 >> 18:24:41.314118 IP 172.28.15.82.3128 > 10.251.22.29.1121: F >> 3799410861:3799410861(0) ack 1573162378 win 33580 >> >> ...at this point, the client should have received the above packets and ACK for >> 3799410862 to include the FIN. >> >> 18:24:41.314744 IP 10.251.22.29.1121 > 172.28.15.82.3128: P >> 1573162378:1573162380(2) ack 3799409121 win 65535 >> >> ...instead it sends an ACK for earlier traffic. The Squid box should be in >> FIN-WAIT-1 and simply ignore this as a dup ACK, rather than sending an RST: >> > > Seems like it is the effect of the SS_NOFDREF check in the > netinet/tcp_input.c, at least it is present in the rev. 1.281.2.5. > > See the post > http://lists.freebsd.org/pipermail/freebsd-current/2007-July/074837.html > That makes perfect sense.. thankyou. I will check this avenue of inquiry. possibly we should do a shutdown() and let the file descriptor exist for a few seconds. > I believe it discuisses the same problem, but for -CURRENT. In > short, Squid child closes the descriptor, so connection is present > in the TCP/IP stack only. And SS_NOFDREF check provokes RST and > invokes tcp_close(). > --------------070601040006030604020807--
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