Date: Thu, 06 Dec 2001 08:27:37 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Yung-Sheng Tang <freebsd@hoolan.org> Cc: freebsd-hackers@freebsd.org Subject: Re: UDP checksum error after encapsulating multicast packet Message-ID: <3C0F9C79.F0B32682@mindspring.com> References: <Pine.BSF.4.05.10112062353370.89778-100000@hoolan.org>
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Yung-Sheng Tang wrote: > I am sorry that I don't get what you mean well. The multicast-sending > AP, mrouted and tcpdump all run on the same machine. From tcpdump > result, the multicast AP gives the right checksum, whereas > encapsulating module(?) gives the wrong checksum, right? So, What next > I should examine for? Ah. I thought you might have a bad source host. See Mark Tinguely's post: he found the problem; it's a byte-order at the tme of calculation problem. I think you would have to HTONS(), do the checksum recalculation, and then HTONS() it back (or delay the recalculation untul after it was naturally HTONS()'ed, if possible). -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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