From owner-freebsd-ipfw Fri Jan 17 14:25:29 2003 Delivered-To: freebsd-ipfw@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 52E3137B401 for ; Fri, 17 Jan 2003 14:25:28 -0800 (PST) Received: from shell.nominum.com (shell.nominum.com [128.177.192.160]) by mx1.FreeBSD.org (Postfix) with ESMTP id 00DFC43F13 for ; Fri, 17 Jan 2003 14:25:28 -0800 (PST) (envelope-from Jian.Song@nominum.com) Received: from nominum.com (yomiko.engr.nominum.com [128.177.194.45]) by shell.nominum.com (Postfix) with ESMTP id B7F0C137F06 for ; Fri, 17 Jan 2003 14:25:27 -0800 (PST) Message-ID: <3E280776.3060502@nominum.com> Date: Fri, 17 Jan 2003 13:39:02 +0000 From: Jian Song User-Agent: Mozilla/5.0 (X11; U; NetBSD i386; en-US; rv:1.0.1) Gecko/20030107 X-Accept-Language: en-us, en, zh, zh-cn, zh-tw MIME-Version: 1.0 To: freebsd-ipfw@FreeBSD.ORG Subject: How to do tcp payload validation Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-freebsd-ipfw@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Hi: I need to do tcp payload validation. Specifically, the tcp stream I am looking at contains multiple messages. Each message has a two byte length header and immediately follow by the body. I would like to monitor the tcp traffic and intercept each message. If there is an error, I will send RSTs to both ends of the connection. While I can do a BPF tap and do ip reassembly and tcp processing myself, I was wondering whether this can be achieved through ipfw or ipfilter. I would like a TCP tap which pass tcp payload data to a user process for further validation. This way, I don't have to worry about matching ACKs and do TCP stream reassembly. Thanks, Jian Song To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-ipfw" in the body of the message