Date: Wed, 25 Aug 2004 18:59:39 -0400 From: Brian Fundakowski Feldman <green@FreeBSD.org> To: "David E. O'Brien" <obrien@FreeBSD.org> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/i386/include in_cksum.h Message-ID: <20040825225939.GM77326@green.homeunix.org> In-Reply-To: <200408251828.i7PISFtH078796@repoman.freebsd.org> References: <200408251828.i7PISFtH078796@repoman.freebsd.org>
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On Wed, Aug 25, 2004 at 06:28:15PM +0000, David E. O'Brien wrote: > obrien 2004-08-25 18:28:15 UTC > > FreeBSD src repository > > Modified files: > sys/i386/include in_cksum.h > Log: > Fix a bug in in_cksum_hdr w/o -O. > > The C code assumes that the carry bit is always kept from the previous > operation. However, the pointer indexing requires another add operation. > Thus, the carry bit from the first operation is tromped over by the > "addl" operation that ends up following it, so the "adcl" that follows > that has no effect because the carry bit is cleared before it. > The result is checksum failure on received packets. Good job! Did you see any similar bugs in other in-line asm you might have glanced at? -- Brian Fundakowski Feldman \'[ FreeBSD ]''''''''''\ <> green@FreeBSD.org \ The Power to Serve! \ Opinions expressed are my own. \,,,,,,,,,,,,,,,,,,,,,,\
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