From owner-freebsd-net@FreeBSD.ORG Thu Apr 5 15:25:51 2007 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id EE63816A401 for ; Thu, 5 Apr 2007 15:25:51 +0000 (UTC) (envelope-from andrew@mcdonald.org.uk) Received: from widget.mcdonald.org.uk (widget.mcdonald.org.uk [81.187.72.227]) by mx1.freebsd.org (Postfix) with ESMTP id A738013C448 for ; Thu, 5 Apr 2007 15:25:51 +0000 (UTC) (envelope-from andrew@mcdonald.org.uk) Received: from admcd by widget.mcdonald.org.uk with local (Exim 4.63) (envelope-from ) id 1HZTqN-0003vj-Go; Thu, 05 Apr 2007 16:25:47 +0100 Date: Thu, 5 Apr 2007 16:25:47 +0100 From: Andrew McDonald To: "JINMEI Tatuya / ?$B?@L@C#:H" Message-ID: <20070405152547.GC6798@mcdonald.org.uk> References: <20070404211815.GA6798@mcdonald.org.uk> <20070405081639.GB6798@mcdonald.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.13 (2006-08-11) Cc: freebsd-net@freebsd.org Subject: Re: IPv6 Router Alert breaks forwarding X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 05 Apr 2007 15:25:52 -0000 On Thu, Apr 05, 2007 at 11:02:42PM +0900, JINMEI Tatuya / ?$B?@L@C#:H wrote: > > The behavior looks reasonable, but I'd code it more explicitly with > some comments so that the intent is clear and others can correctly > modify it for future extensions. A possible patch to implement it is > pasted below. One thing I'm not really sure is whether someone is > using (or has used) other predefined alert values: > > 1 Datagram contains RSVP message. > 2 Datagram contains an Active Networks message. > > (I guess you're now going to use values 3-35 per RFC3175). > > If there is a user, we need to be careful not to break compatibility. That patch looks good to me. I think RSVP is the only other potential current user (and most likely without RFC3175 support). There appears to be some basic support for IPv6 in the ISI RSVPd implementation (untouched since 1999), but from a quick look at the code it is not clear whether they actually use the IPv6 router alert anyway. It predates RFC3175. If you want to be very conservative in changing behaviour you might want to include RSVP, but it seems unlikely that anyone is using it. The only reference I know of for the Active Networks use is a published paper (and the reference in RFC2711). I don't know of any running code. I'm mainly interested in new allocations (i.e. values above 35). Thanks. -- Andrew McDonald E-mail: andrew@mcdonald.org.uk http://www.mcdonald.org.uk/andrew/