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authorSabrina Dubroca <sd@queasysnail.net>2017-03-13 13:28:09 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-03-22 12:04:17 +0100
commit5f8bc3856e285cc12597879039c17f7397f4b37d (patch)
tree9ea8cf4f9de0eada9f331e336c98d45b2392746a /net/ipv6
parentb57955ea30e13aa37e5955bf20617f839f32c560 (diff)
ipv6: make ECMP route replacement less greedy
[ Upstream commit 67e194007be08d071294456274dd53e0a04fdf90 ] Commit 27596472473a ("ipv6: fix ECMP route replacement") introduced a loop that removes all siblings of an ECMP route that is being replaced. However, this loop doesn't stop when it has replaced siblings, and keeps removing other routes with a higher metric. We also end up triggering the WARN_ON after the loop, because after this nsiblings < 0. Instead, stop the loop when we have taken care of all routes with the same metric as the route being replaced. Reproducer: =========== #!/bin/sh ip netns add ns1 ip netns add ns2 ip -net ns1 link set lo up for x in 0 1 2 ; do ip link add veth$x netns ns2 type veth peer name eth$x netns ns1 ip -net ns1 link set eth$x up ip -net ns2 link set veth$x up done ip -net ns1 -6 r a 2000::/64 nexthop via fe80::0 dev eth0 \ nexthop via fe80::1 dev eth1 nexthop via fe80::2 dev eth2 ip -net ns1 -6 r a 2000::/64 via fe80::42 dev eth0 metric 256 ip -net ns1 -6 r a 2000::/64 via fe80::43 dev eth0 metric 2048 echo "before replace, 3 routes" ip -net ns1 -6 r | grep -v '^fe80\|^ff00' echo ip -net ns1 -6 r c 2000::/64 nexthop via fe80::4 dev eth0 \ nexthop via fe80::5 dev eth1 nexthop via fe80::6 dev eth2 echo "after replace, only 2 routes, metric 2048 is gone" ip -net ns1 -6 r | grep -v '^fe80\|^ff00' Fixes: 27596472473a ("ipv6: fix ECMP route replacement") Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Reviewed-by: Xin Long <lucien.xin@gmail.com> Reviewed-by: Michal Kubecek <mkubecek@suse.cz> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/ip6_fib.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 34cf46d74554..85bf86458706 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -903,6 +903,8 @@ add:
ins = &rt->dst.rt6_next;
iter = *ins;
while (iter) {
+ if (iter->rt6i_metric > rt->rt6i_metric)
+ break;
if (rt6_qualify_for_ecmp(iter)) {
*ins = iter->dst.rt6_next;
fib6_purge_rt(iter, fn, info->nl_net);