From b673d6cceae2b3e106addd27b79d321cc739bd43 Mon Sep 17 00:00:00 2001 From: Jakub Sitnicki Date: Wed, 23 Aug 2017 09:58:31 +0200 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- net/ipv6/route.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 246e7d7d30a4..4d0273459d49 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -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) */ -- 2.20.1