From owner-freebsd-hackers Sat Dec 15 9:48:23 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from cu518.adelaide.adsl.on.net (cu518.adelaide.adsl.on.net [150.101.236.10]) by hub.freebsd.org (Postfix) with ESMTP id 7BC5B37B416 for ; Sat, 15 Dec 2001 09:48:18 -0800 (PST) Received: from ns.aus.com (cu518.adsl.adelaide.on.net [127.0.0.1]) by cu518.adelaide.adsl.on.net (8.11.0/8.11.0) with ESMTP id fBFJut713917 for ; Sun, 16 Dec 2001 06:26:55 +1030 Message-ID: <3C1B96A9.5060804@ns.aus.com> Date: Sun, 16 Dec 2001 05:00:01 +1030 From: Richard Sharpe Reply-To: rsharpe@ns.aus.com User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.4) Gecko/20010917 X-Accept-Language: en-us MIME-Version: 1.0 To: freebsd-hackers@freebsd.org Subject: Re: Does anyone know if the Broadcom BCM5700 has problems with HW csum? References: <3C1AEA9E.6010502@ns.aus.com> <20011215010457.B84861@nexus.root.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG David Greenman wrote: >>I am playing with a driver for the Broadcom 5700/5701. >> >>It recognizes the 5700 in my 3Com cards OK, but seems to screw up the >>TCP checksum. >> >>Switching off hardware checksum capability fixes it. >> >>Does anyone know the details of which stepping this stuff worked on? >> > > I haven't nailed down the problem that I've seen with them to a specific >chipset, but I can confirm that they incorrectly calculate the checksum on >input packets in some cases. It seems to be related to both packet size and >certain TCP options (or lack of them). I've only seen the problem occur with >very small (0-4 byte payload) packets. > In any case, after discussing this problem with Bill Paul, I disabled >input checksum in the -current driver and intend to merge that to -stable in >a few days. > OK, that makes sense, because I wasn't getting past first base. SYN ACK segments werre being rejected with bad checksum. The driver I modified is actually for the 5701, which works fine with all checksum offloading enabled. I will try to disable just receive TCP checksum and see what happens. -- Richard Sharpe, rsharpe@ns.aus.com, LPIC-1 www.samba.org, www.ethereal.com, SAMS Teach Yourself Samba in 24 Hours, Special Edition, Using Samba To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message