From owner-freebsd-net@FreeBSD.ORG Thu Dec 10 19:26:58 2009 Return-Path: Delivered-To: freebsd-net@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id AAEC41065670 for ; Thu, 10 Dec 2009 19:26:58 +0000 (UTC) (envelope-from ras@gerbil.cluepon.net) Received: from gerbil.cluepon.net (e-gerbil.net [69.31.1.2]) by mx1.freebsd.org (Postfix) with ESMTP id 705958FC14 for ; Thu, 10 Dec 2009 19:26:57 +0000 (UTC) Received: from gerbil.cluepon.net (ras@localhost [127.0.0.1]) by gerbil.cluepon.net (8.14.3/8.14.3) with ESMTP id nBAJ357J085044 for ; Thu, 10 Dec 2009 13:03:05 -0600 (CST) (envelope-from ras@gerbil.cluepon.net) Received: (from ras@localhost) by gerbil.cluepon.net (8.14.3/8.14.3/Submit) id nBAJ35CT085043 for freebsd-net@FreeBSD.org; Thu, 10 Dec 2009 13:03:05 -0600 (CST) (envelope-from ras) Date: Thu, 10 Dec 2009 13:03:05 -0600 From: Richard A Steenbergen To: freebsd-net@FreeBSD.org Message-ID: <20091210190305.GT45152@gerbil.cluepon.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.13 (2006-08-11) Cc: Subject: ping6 and a do-not-fragment option 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, 10 Dec 2009 19:26:58 -0000 Hi, I just noticed, while trying to do a little debugging, that ping6 doesn't seem to have a way to specify "do not fragment" like ping does for IPv4. Obviously the way this is implemented has been changed, since there is no longer a DF-bit in IPv6, but it looks like there is already an IPV6_DONTFRAG setsockopt() available for exactly this purpose. It looks like IPV6_DONTFRAG got added at a later date (from RFC3542), perhaps after ping6 was initially written. It seems like the correct fix would be to add a cli option to ping6 (perhaps 'D', since it's available and matches the command in ping) to call this setsockopt() and implement a "do not fragment" option. -- Richard A Steenbergen http://www.e-gerbil.net/ras GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)