Date: Wed, 28 Jul 2004 22:48:28 +0400 (MSD) From: Maxim Konovalov <maxim@macomnet.ru> To: othermark <atkin901@yahoo.com> Cc: freebsd-current@freebsd.org Subject: Re: fixing out of order first fragment processing? Message-ID: <20040728221230.O99844@mp2.macomnet.net> In-Reply-To: <cdpbts$om0$1@sea.gmane.org> References: <cdpbts$om0$1@sea.gmane.org>
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Hello, On Thu, 22 Jul 2004, 14:34-0700, othermark wrote: > Hi, > > This is one of those obscure, yet well known issues in FreeBSD, > some network stacks, like Linux, send the udp/icmp fragment > first (if multiple frags -- in reverse order), then the orginal > packet with the header. > > In -current, we still cannot process this simple fragged icmp-echo > request from a Linux host. For example, 'ping -c 1 -s 1500 <freebsd ip>'. > > FreeBSD discards the frag(s) and when it sees the initial packet with > header waits for the frags. > > So two questions: > > 1. is there a gnats pr? I tried various searches with no success. AFAIK no. > 2. are there workarounds/patches? First of all, I can't reproduce this behaviour. "ping -c 1 -s 4500 freebsd" from the linux produces a pseudo tcpdump liek below: linux > freebsd: icmp (frag 64465:68@4440) linux > freebsd: icmp (frag 64465:1480@2960+) linux > freebsd: icmp (frag 64465:1480@1480+) linux > freebsd: icmp: echo request (frag 64465:1480@0+) freebsd > linux: icmp: echo reply (frag 6529:1480@0+) freebsd > linux: icmp (frag 6529:1480@1480+) freebsd > linux: icmp (frag 6529:1480@2960+) freebsd > linux: icmp (frag 6529:68@4440) Linux kernel is 2.4.20-ac2, FreeBSD is 5.2.1-RELEASE. What are yours? Could you provide netstat -sp ip | grep frag snippet from the FreeBSD box? Clear the stats (netstat -zs) before experiments is a good idea as well. -- Maxim Konovalov
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