From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felix von Leitner Subject: Re: IPv6 has trouble assigning an interface Date: Tue, 26 Apr 2005 08:10:11 +0200 Message-ID: <20050426061011.GA8527@codeblau.de> References: <20050311202122.GA13205@fefe.de> <20050311173308.7a076e8f.akpm@osdl.org> <20050324.205902.119922975.yoshfuji@linux-ipv6.org> <20050425195736.GB3123@codeblau.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "YOSHIFUJI Hideaki / ?$B5HF#1QL@" , linux-kernel@vger.kernel.org, netdev@oss.sgi.com Return-path: To: Pekka Savola Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Thus spake Pekka Savola (pekkas@netcore.fi): > >Here is an strace of some piece of code of mine: > > > >socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP) = 3 > >setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [12884901889], 4) = 0 > >bind(3, {sa_family=AF_INET6, sin6_port=htons(8002), inet_pton(AF_INET6, > >"::", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = 0 > >setsockopt(3, SOL_IPV6, IPV6_MULTICAST_LOOP, "\1", 1) = 0 > >[...] > >sendto(3, "ncp-lowfat-1.2.2", 16, 0, {sa_family=AF_INET6, > >sin6_port=htons(8002), inet_pton(AF_INET6, "ff02::6e63:7030", &sin6_addr), > >sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1 EADDRNOTAVAIL (Cannot assign > >requested address) > > > >ff02 is a link-local multicast address. I've bound to ::. How can this > >fail? link-local should always work, even if no routes are set and no > >router has been found. > Umm.. link-local unicast and multicast both require that you specify > the interface, because otherwise it's ambiguous -- how could the > kernel know which interface should be used to send the packet? OK for unicast. But multicast? I expected link-local multicast to send on _all_ interfaces if I don't specify one. Felix