From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: IPV6_PKTINFO seems not to be honored correctly by RAW-sockets Date: Tue, 30 Oct 2012 11:42:48 +0100 Message-ID: <1351593768.12280.779.camel@edumazet-glaptop> References: <508F969C.9080300@midlink.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Steven Barth Return-path: Received: from mail-bk0-f46.google.com ([209.85.214.46]:51534 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758201Ab2J3Kmw (ORCPT ); Tue, 30 Oct 2012 06:42:52 -0400 Received: by mail-bk0-f46.google.com with SMTP id jk13so71779bkc.19 for ; Tue, 30 Oct 2012 03:42:50 -0700 (PDT) In-Reply-To: <508F969C.9080300@midlink.org> Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Dumazet On Tue, 2012-10-30 at 09:58 +0100, Steven Barth wrote: > Hi, > > I recently noticed that there might be an unexpected behavior in the > handling of IPV6_PKTINFO for RAW-sockets. It seems that the given > destination interface is ignored. > > I just reproduced this on 3.7.0-rc3 vanilla but some quick tests with > 2.6.32 and 3.5 distro-kernels on different machines showed the same. > > I've noticed this first in my own software but I could also reproduce it > easily with standard tools like ping6 from iputils: > > Have 2 network interfaces with (global) IPv6-addresses assigned (e.g. > eth0 with fd00::1/64 and eth1 with fd01::1/64) and do a ping6 -I eth1 > fd00::1 (ping6 from iputils uses IPV6_PKTINFO internally). > > For me the result was that even though I set the interface to eth1 the > ECHO was still send to eth0. > > Also (although probably unrelated) forwarding for IPv6 was disabled. > > If I try something similar with IPv4 and ping -I ... the ECHO doesn't go > out on eth0 but - as expected - on eth1. > > However if I use traceroute(6) with -I (ICMP-traceroute) and the -i > option to determine the interface, packages seem to be sent through the > expected interface. Internally it seems that traceroute(6) uses > SO_BINDTODEVICE instead of IP(V6)_PKTINFO which seems to work. > > So it seems there might be something wrong with IPV6_PKTINFO or is this > expected behavior? > I believe its not expected behavior. Is the following patch fixing it ? Thanks [PATCH] ipv6: raw: honor IPV6_PKTINFO Let ping6 -I interface works correctly. If socket was not bound to a given interface, check if IPV6_PKTINFO was issued on this socket. Reported-by: Steven Barth Signed-off-by: Eric Dumazet --- diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c index d8e95c7..363ee65 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -814,8 +814,8 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk, fl6.flowlabel = np->flow_label; } - if (fl6.flowi6_oif == 0) - fl6.flowi6_oif = sk->sk_bound_dev_if; + if (!fl6.flowi6_oif) + fl6.flowi6_oif = sk->sk_bound_dev_if ?: np->sticky_pktinfo.ipi6_ifindex; if (msg->msg_controllen) { opt = &opt_space;