[PATCH net-next v3 4/4] ipv6: Use multipath hash from flow info if available
From: Jakub Sitnicki <hidden>
Date: 2017-08-23 07:58:42
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
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 <redacted> --- 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 246e7d7..4d02734 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) */
--
2.9.4