From 95eac9e6ab5f2c7a78ce43b502058d129053acdf Mon Sep 17 00:00:00 2001 From: Benjamin Poirier Date: Wed, 12 Feb 2020 10:41:06 +0900 Subject: [PATCH] ipv6: Fix route replacement with dev-only route [ Upstream commit e404b8c7cfb31654c9024d497cec58a501501692 ] After commit 27596472473a ("ipv6: fix ECMP route replacement") it is no longer possible to replace an ECMP-able route by a non ECMP-able route. For example, ip route add 2001:db8::1/128 via fe80::1 dev dummy0 ip route replace 2001:db8::1/128 dev dummy0 does not work as expected. Tweak the replacement logic so that point 3 in the log of the above commit becomes: 3. If the new route is not ECMP-able, and no matching non-ECMP-able route exists, replace matching ECMP-able route (if any) or add the new route. We can now summarize the entire replace semantics to: When doing a replace, prefer replacing a matching route of the same "ECMP-able-ness" as the replace argument. If there is no such candidate, fallback to the first route found. Fixes: 27596472473a ("ipv6: fix ECMP route replacement") Signed-off-by: Benjamin Poirier Reviewed-by: Michal Kubecek Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ip6_fib.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index c23e02a7ccb0..30eb8bdcdbda 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -780,8 +780,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, found++; break; } - if (rt_can_ecmp) - fallback_ins = fallback_ins ?: ins; + fallback_ins = fallback_ins ?: ins; goto next_iter; } @@ -821,7 +820,9 @@ next_iter: } if (fallback_ins && !found) { - /* No ECMP-able route found, replace first non-ECMP one */ + /* No matching route with same ecmp-able-ness found, replace + * first matching route + */ ins = fallback_ins; iter = *ins; found++;