On Sat, Apr 25, 2015 at 08:54:13PM +0100, Chris Boot wrote: > The problem happens because BIRD doesn’t verify the checksum by running > Fletcher against the received packet and testing for zero; rather it: > - sets the checksum in the packet to 0 > - runs the checksum calculation on the LSA data > - updates the checksum in the packet (and comes up with a different result) > - complains when the result is not the same as what was in the packet > > I believe the correct way to verify the checksum would be to run the > algorithm against the unchanged packet (with the checksum intact) and verify > that the result is zero. > > Would a patch that changes this behaviour be welcome? I’ve written something > up against the current git master, but haven’t yet tested it.
Hello You are most likley right. As i understand it, these checksums are modulo 255; therefore, in some cases they are not unique. Therefore simple computing new value and comparing it with received does not work. A patch would be definitely welcome. -- Elen sila lumenn' omentielvo Ondrej 'Santiago' Zajicek (email: santi...@crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."
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