From owner-freebsd-net Tue Aug 6 11:57: 8 2002 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 17F4D37B400 for ; Tue, 6 Aug 2002 11:57:05 -0700 (PDT) Received: from hotmail.com (f79.law9.hotmail.com [64.4.9.79]) by mx1.FreeBSD.org (Postfix) with ESMTP id C965543E77 for ; Tue, 6 Aug 2002 11:57:04 -0700 (PDT) (envelope-from soheil_h_y@hotmail.com) Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Tue, 6 Aug 2002 11:57:04 -0700 Received: from 80.78.135.8 by lw9fd.law9.hotmail.msn.com with HTTP; Tue, 06 Aug 2002 18:57:04 GMT X-Originating-IP: [80.78.135.8] From: "soheil h" To: freebsd-net@FreeBSD.ORG Subject: Re: TCP HEADER Date: Tue, 06 Aug 2002 23:27:04 +0430 Mime-Version: 1.0 Content-Type: text/plain; format=flowed Message-ID: X-OriginalArrivalTime: 06 Aug 2002 18:57:04.0651 (UTC) FILETIME=[0E17D5B0:01C23D7B] Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Hi list In any tcp/ip packet pass through my FreeBSD gateway i duplicate the tcp window by changing /usr/src/sys/netinet/ip_input.c . The clients just stay at SYN-SENT state ( the ACK of their SYN ) is not recieved . when i run tcpdump on the gateway it show something like this: time x.x.x.x.p > y.y.y.y.80 : S seq1:seq1(0) win x < options > /in time x.x.x.x.p > y.y.y.y.80 : S seq1:seq1(0) win 2*x /out (no SYN|ACK recieved ) !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! (just for test when the y.y.y.y is a site that i can access and no packet from x.x.x.x recieved showed by the tcpdump at y.y.y.y;) it shows when the tcp/ip packet pass through me the window size is duplicated . ( no change in any other members ). as stated in Stevens' TCP/IP Illustrated the window size is just for date transition not for the connection stablishment. i think some host between drop my packet but i correct the cksums : in my code ,after the change, the checksums are treated as ip->ip_sum = in_cksum(m, hlen); th stands for the TCP header : len = ip->ip_len; th->th_sum = in_cksum(m, len); but i don't know what is the problem with my algorithm ? Please verify me if the cksum calculation is not true , or any other errors might be occured this is so emergency for me; Please help me! S.H.Y _________________________________________________________________ MSN Photos is the easiest way to share and print your photos: http://photos.msn.com/support/worldwide.aspx To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message