From owner-freebsd-hackers Sat Apr 6 23:06:30 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id XAA20248 for hackers-outgoing; Sat, 6 Apr 1996 23:06:30 -0800 (PST) Received: from time.cdrom.com (time.cdrom.com [204.216.27.226]) by freefall.freebsd.org (8.7.3/8.7.3) with ESMTP id XAA20243 for ; Sat, 6 Apr 1996 23:06:28 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by time.cdrom.com (8.7.5/8.6.9) with SMTP id XAA10021 for ; Sat, 6 Apr 1996 23:05:51 -0800 (PST) Prev-Resent: Sat, 06 Apr 1996 23:05:50 -0800 Prev-Resent: "hackers@freebsd.org " Received: from doorstep.unety.net (root@usi-00-10.Naperville.unety.net [204.70.107.30]) by time.cdrom.com (8.7.5/8.6.9) with SMTP id WAA09961 for ; Sat, 6 Apr 1996 22:31:05 -0800 (PST) Received: from webster.unety.net (webster.unety.net [206.31.202.8]) by doorstep.unety.net (8.6.9/8.6.9) with SMTP id AAA02011 for ; Sun, 7 Apr 1996 00:26:25 -0600 Received: by webster.unety.net with Microsoft Mail id <01BB2419.36344C40@webster.unety.net>; Sun, 7 Apr 1996 00:28:58 -0600 Message-ID: <01BB2419.36344C40@webster.unety.net> From: Jim Fleming To: "'Jordan K. Hubbard'" Subject: Check IP Version Date: Sun, 7 Apr 1996 00:28:56 -0600 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Resent-To: hackers@freebsd.org Resent-Date: Sat, 06 Apr 1996 23:05:51 -0800 Resent-Message-ID: <10019.828860751@time.cdrom.com> Resent-From: "Jordan K. Hubbard" Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Jordan, I am starting to develop a substantialliy modified version of the IP protocol. As specified in the IP protocol the ip_v (IP Version) field of the IP header should be set to 4. (see /usr/src/sys/netinet/ip.h) It is not desirable for new versions of IP to "break" existing code. I have not provide this but in studying the SLIP code I see that there is never really a check done to see of the IP header is of version 4. The TCP header is checked as follows... Line 557 of /usr/src/sys/net/if_sl.c if ((ip = mtod(m, struct ip *))->ip_p == IPPROTO_TCP) { I suggest that you might want to change this to... if ((ip = mtod(m, struct ip *))->ip_v == IPVERSION) && (ip->ip_p == IPPROTO_TCP)) { ...just to make sure... By the way...I think PPP is OK...I will keep looking... -- Jim Fleming UNETY Systems, Inc. Naperville, IL 60563 e-mail: JimFleming@unety.net