From owner-freebsd-net Fri Nov 30 13:34:27 2001 Delivered-To: freebsd-net@freebsd.org Received: from herbelot.dyndns.org (d211.dhcp212-26.cybercable.fr [212.198.26.211]) by hub.freebsd.org (Postfix) with ESMTP id 9227537B417 for ; Fri, 30 Nov 2001 13:34:24 -0800 (PST) Received: from herbelot.com (multi.herbelot.nom [192.168.1.2]) by herbelot.dyndns.org (8.9.3/8.9.3) with ESMTP id XAA75067; Fri, 30 Nov 2001 23:11:21 +0100 (CET) (envelope-from thierry@herbelot.com) Message-ID: <3C07FB4B.E7D10D4E@herbelot.com> Date: Fri, 30 Nov 2001 22:34:03 +0100 From: Thierry Herbelot X-Mailer: Mozilla 4.79 [en] (X11; U; Linux 2.4.2 i386) X-Accept-Language: en MIME-Version: 1.0 To: Ryan Mooney Cc: freebsd-net@FreeBSD.ORG Subject: Re: Capturing packets w/ bad CRC's? References: <20011130110412.D2514@pcslink.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit 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 Ryan Mooney wrote: > > Hello, > > I'm trying to write an ethernet level network tester to test a wireless > gigabit product the company I'm working for has developed. I need > to be able to get packets off a Gig-E interface that have bad CRC > checksums so I can see how badly mangled they are. I've tried using > pcap and ng_ether int: lowerboth of which are giving me just the "good" > packets. > > Right now they are being discarded somewhere below the bpf interface. > I'm not sure where, I've read through a bunch of the *if* code, but they are discarded by the Ethernet chipset itself, and this the reason why you don't see any source code for managing bad frames. [SNIP] > > If anyone knows how I can get the bad packets to examine them, I'd much > appreciate it. typically by tweaking the chipset, if at all possible, in order to see also bea frames -- Thierry Herbelot To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message