From owner-freebsd-questions Thu Oct 26 17:12:50 2000 Delivered-To: freebsd-questions@freebsd.org Received: from ihemail1.firewall.lucent.com (ihemail1.lucent.com [192.11.222.161]) by hub.freebsd.org (Postfix) with ESMTP id 52A9337B479; Thu, 26 Oct 2000 17:12:45 -0700 (PDT) Received: from ihemail1.firewall.lucent.com (localhost [127.0.0.1]) by ihemail1.firewall.lucent.com (Pro-8.9.3/8.9.3) with ESMTP id UAA00783; Thu, 26 Oct 2000 20:12:44 -0400 (EDT) Received: from mhmail.mh.lucent.com (h135-3-115-8.lucent.com [135.3.115.8]) by ihemail1.firewall.lucent.com (Pro-8.9.3/8.9.3) with ESMTP id UAA00777; Thu, 26 Oct 2000 20:12:44 -0400 (EDT) Received: from lucent.com (positron.micro.lucent.com [192.19.56.129]) by mhmail.mh.lucent.com (8.8.8+Sun/EMS-1.5 sol2) id UAA28869; Thu, 26 Oct 2000 20:12:42 -0400 (EDT) Message-ID: <39F8C82E.2C61CF55@lucent.com> Date: Thu, 26 Oct 2000 20:11:26 -0400 From: "Gary T. Corcoran" Reply-To: gcorcoran@lucent.com Organization: Lucent Microelectronics - Client Access Broadband Systems X-Mailer: Mozilla 4.73 [en] (Win95; U) X-Accept-Language: en MIME-Version: 1.0 To: Aaron Hill Cc: julian@elischer.org, freebsd-questions@FreeBSD.ORG, freebsd-net@FreeBSD.ORG Subject: Re: More on PPPoE & ADSL (Telstra Bigpond) References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Aaron Hill wrote: ... > I agree, I think it's tcpdump trying, incorrectly, to interpret the tag > contents. In case you'd like to see what the Host-Uniq tags actually > contained here's some hex of the Windows PADI frame... > > 0:10:5a:0:d3:de Broadcast 8863 60: PPPoE PADI [Host-Uniq UTF8] [Service-Name > "bigpond"] > 0x0000 1109 0000 0015 0103 0006 0010 5a00 d3de ............Z... > 0x0010 0101 0007 6269 6770 6f6e 6400 0000 0000 ....bigpond..... > 0x0020 0000 0000 0000 0000 0000 0000 0000 .............. > > ... and the FreeBSD PADI frame... > > 0:e0:29:73:81:dd Broadcast 8863 60: PPPoE PADI [Service-Name "bigpond"] > [Host-Uniq UTF8] > 0x0000 1109 0000 0013 0101 0007 6269 6770 6f6e ..........bigpon > 0x0010 6401 0300 0480 7067 c300 0000 0000 0000 d.....pg........ > 0x0020 0000 0000 0000 0000 0000 0000 0000 .............. This would be a bug in the head-end and not the FreeBSD implementation, but what if... The Windows PADI frame accidentally has the Service-Name terminated with a NULL. It is NOT required by the standard, but what if the head-end is scanning for the Service-Name string that way? The way the FreeBSD frame is constructed, with the Host-Uniq tag immediately after the Service-Name, it is not (pseudo) NULL-terminated, and never will be for this format. Just to make it clear, it is not _supposed_ to be Null-terminated, but if the head-end has this bug, both the Windows and Linux implementations would happen to satisfy it. Just a thought... Gary To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message