From owner-freebsd-net@FreeBSD.ORG Tue Jul 31 22:25:22 2007 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 5F8CA16A417; Tue, 31 Jul 2007 22:25:22 +0000 (UTC) (envelope-from bms@incunabulum.net) Received: from out2.smtp.messagingengine.com (out2.smtp.messagingengine.com [66.111.4.26]) by mx1.freebsd.org (Postfix) with ESMTP id 330AF13C45D; Tue, 31 Jul 2007 22:25:22 +0000 (UTC) (envelope-from bms@incunabulum.net) Received: from compute1.internal (compute1.internal [10.202.2.41]) by out1.messagingengine.com (Postfix) with ESMTP id 23376B43A; Tue, 31 Jul 2007 18:25:20 -0400 (EDT) Received: from heartbeat1.messagingengine.com ([10.202.2.160]) by compute1.internal (MEProxy); Tue, 31 Jul 2007 18:25:21 -0400 X-Sasl-enc: pyYwRSnSE09O/8joa2sjtAyJvQVDBt0glvGezQeicvR8 1185920720 Received: from [192.168.123.18] (82-35-112-254.cable.ubr07.dals.blueyonder.co.uk [82.35.112.254]) by mail.messagingengine.com (Postfix) with ESMTP id 942B2511B; Tue, 31 Jul 2007 18:25:19 -0400 (EDT) Message-ID: <46AFB6C9.20401@incunabulum.net> Date: Tue, 31 Jul 2007 23:25:13 +0100 From: "Bruce M. Simpson" User-Agent: Thunderbird 1.5.0.12 (Windows/20070509) MIME-Version: 1.0 To: "Christian S.J. Peron" References: <20070731162515.GA3684@sub> <46AF7E57.5020209@incunabulum.net> <20070731204156.GA7614@sub> In-Reply-To: <20070731204156.GA7614@sub> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-net@freebsd.org, rwatson@freebsd.org Subject: Re: divert and deadlock issues 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: Tue, 31 Jul 2007 22:25:22 -0000 Christian S.J. Peron wrote: >> I can't think of a reason why a user would wish to supply any multicast >> socket options to a divert socket, other than the 'small' ones, i.e. >> IP_MULTICAST_TTL/IF/LOOP/VIF. >> > > Why would these options ever be set on the divert socket itself though? > To me it would make sense if these options were set on the network > socket that originally sent the multicast packet itself. > They shouldn't be necessary, however I can foresee situations where someone might well want to redirect multicast datagrams traversing an IPPROTO_DIVERT socket, by using these socket options. [Recall that FreeBSD's IPv4 stack currently uses the destination address as the sole primary key for lookups in the forwarding information base's radix trie.] This is however very unlikely, so my last suggestion, that multicast options be deprecated or forbidden for IPPROTO_DIVERT sockets, stands. Kind regards BMS