Date: Thu, 20 Sep 2001 22:40:26 -0500 From: Matt Finlay <matt@ipperformance.com> To: Les Biffle <les@safety.net>, davep@afterswish.com, Alfred Perlstein <bright@mu.org>, hackers@FreeBSD.ORG Subject: Re: sendto not sending what I asked... Message-ID: <3BAAB6AA.9D7EDD99@ipperformance.com> References: <200109210250.f8L2oO615274@ns3.safety.net> <3BAAB547.C065FF97@ipperformance.com>
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come to think of it... perhaps you are not calculating the tcp checksum correctly because of the tcp/ip pseudo header. i no longer have the code that was posted, but thinking back i believe this might be the case. Matt Finlay wrote: > Les Biffle wrote: > > > > pkt.ipbit.ip_sum=in_cksum((unsigned short*)(void*)&pkt,20); > > > pkt.tcpbit.th_sum=tcpsum(&pkt.ipbit); > > > > You need to do the TCP checksum first. It changes the payload (the TCP > > checksum). The IP checksum includes all data, so must be done after the > > payload changes are done. > > i think this is incorrect. the IP checksum only includes the IP header and > any IP options. therefore order should not matter. > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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