Am 24.01.2011 18:02, schrieb Mario 'BitKoenig' Holbe: > On Mon, Jan 24, 2011 at 05:10:50PM +0100, Patrick McHardy wrote: >>> Yes, disabling the ip6_route_me_harder() call in ip6t_mangle_out() >>> results in the advertisements being transmitted on the correct >>> interfaces >> Thanks. The problem appears to be that ip6_route_me_harder() >> only uses the socket's oif for the route lookup when the >> socket is bound to an interface, but radvd uses IPV6_PKTINFO >> to specify the outgoing interface. >> >> I guess netfilter shouldn't be overriding IPV6_PKTINFO, but >> we unfortunately have neither an indication of this nor the >> original route lookup keys available at the time the packet >> is rerouted. > > Mh, I'm not sure, but I guess an indication of netfilter not overriding > IPV6_PKTINFO could be the fact that the source address does not > change... No, ip6_route_me_harder() only attaches a new route to the packet, the packets contents are not changed. > From my 1st mail: > | # ip6tables -t mangle -A OUTPUT -o eth0 -j MARK --set-mark 1 > | # /etc/init.d/radvd start > | -> eth0: <no traffic> > | -> eth1: fe80::2a0:c9ff:fee6:90ce > ff02::1: prefix 2001:6f8:90c:10::/64 > | -> eth1: fe80::2d0:b7ff:fe06:6b36 > ff02::1: prefix 2001:6f8:90c:12::/64 > > fe80::2d0:b7ff:fe06:6b36 is the link-local address of eth0 set by radvd > in IPV6_PKTINFO as well. This, of course, is no guarantee for > ipi6_ifindex not being changed, but I believe if something would have > changed it, it would also have changed ipi6_addr. No, what is happening is that radvd sends the packet with a specified ifindex using IPV6_PKTINFO. The mangle table notices that the mark changes and calls ip6_route_me_harder(), which performs a new route lookup without taking the specified oif into account. It therefore chooses the first of your two routes and sends the packet out eth1. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
