Date: Thu, 16 May 2002 17:26:32 +1000 (EST) From: Cristan Szmajda <cls@cse.unsw.edu.au> To: Giorgos Keramidas <keramida@FreeBSD.ORG> Cc: current@FreeBSD.ORG Subject: Re: bad tcp cksum fffe! Message-ID: <Pine.GSO.4.44.0205161719480.15479-100000@mozart.orchestra.cse.unsw.EDU.AU> In-Reply-To: <20020514173036.GF5715@hades.hell.gr>
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Dear Giorgos, Thanks for your suggestion! The problem has gone away by backing off to -O1 in kernel and -O2 in userland. Strange, because I have been using -O3 -fomit-frame-pointer for a while now (/usr/share/examples/etc/make.conf notwithstanding) with ill effects. My bad. Sorry, but I can't be more specific on which particular flag or which particular CVS update caused the problem. CPU too slow. Thanks again, -- Chris On Tuesday, Giorgos Keramidas said: > On 2002-05-14 17:39, Cristan Szmajda wrote: > > Dear freebsd-current, > > > > Any suggestions you have regarding this problem would be > > much appreciated. > > > > My laptop running -CURRENT is suddenly generating bad TCP > > checksums when talking to some IPs but not others. For > > example, 129.94.209.220 is a problem, > > > > 17:08:47.026823 129.94.233.200.1032 > 129.94.209.220.22: S > > [bad tcp cksum fffe!] 3868790363:3868790363(0) win 65535 > > <mss 1460,nop,wscale 1,nop,nop,timestamp 542813 0,nop,nop,ccnew 10> > > (DF) (ttl 64, id 347, len 68) > > I've seen this only twice. The first time I was using too funky > optimizations to the CFLAGS of my kernel, and GCC was obviously doing > something wrong with the checksum generation code. If this is the > case, then rebuild your kernel and userland with the suggested > optimizations from /usr/share/examples/etc/make.conf and see if this > fixes things for you. > > The second one was when my tcpdump (and the rest of the userland) was > really VERY out of sync with the running kernel (I had managed to > upgrade only the kernel and tcpdump was probably reading random data > from bpf). But there were other more important things wrong with this > case. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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