Commit b673d6cc authored Aug 23, 2017 by Jakub Sitnicki Committed by David S. Miller Aug 24, 2017

ipv6: Use multipath hash from flow info if available



Allow our callers to influence the choice of ECMP link by honoring the
hash passed together with the flow info. This allows for special
treatment of ICMP errors which we would like to route over the same path
as the IPv6 datagram that triggered the error.

Also go through rt6_multipath_hash(), in the usual case when we aren't
dealing with an ICMP error, so that there is one central place where
multipath hash is computed.

Signed-off-by: Jakub Sitnicki <jkbs@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 956b4531

net/ipv6/route.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -452,7 +452,13 @@ static struct rt6_info rt6_multipath_select(struct rt6_info match,
		struct rt6_info sibling, next_sibling;
		int route_choosen;

		route_choosen = get_hash_from_flowi6(fl6) % (match->rt6i_nsiblings + 1);
		/* We might have already computed the hash for ICMPv6 errors. In such
		* case it will always be non-zero. Otherwise now is the time to do it.
		*/
		if (!fl6->mp_hash)
		fl6->mp_hash = rt6_multipath_hash(fl6, NULL);

		route_choosen = fl6->mp_hash % (match->rt6i_nsiblings + 1);
		/* Don't change the route, if route_choosen == 0
		* (siblings does not include ourself)
		*/