From 6ab8a5a3a0029232430acead78a5719ad5cf1917 Mon Sep 17 00:00:00 2001 From: Benjamin Poirier Date: Wed, 12 Feb 2020 10:41:07 +0900 Subject: [PATCH] ipv6: Fix nlmsg_flags when splitting a multipath route [ Upstream commit afecdb376bd81d7e16578f0cfe82a1aec7ae18f3 ] When splitting an RTA_MULTIPATH request into multiple routes and adding the second and later components, we must not simply remove NLM_F_REPLACE but instead replace it by NLM_F_CREATE. Otherwise, it may look like the netlink message was malformed. For example, ip route add 2001:db8::1/128 dev dummy0 ip route change 2001:db8::1/128 nexthop via fe80::30:1 dev dummy0 \ nexthop via fe80::30:2 dev dummy0 results in the following warnings: [ 1035.057019] IPv6: RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE [ 1035.057517] IPv6: NLM_F_CREATE should be set when creating new route This patch makes the nlmsg sequence look equivalent for __ip6_ins_rt() to what it would get if the multipath route had been added in multiple netlink operations: ip route add 2001:db8::1/128 dev dummy0 ip route change 2001:db8::1/128 nexthop via fe80::30:1 dev dummy0 ip route append 2001:db8::1/128 nexthop via fe80::30:2 dev dummy0 Fixes: 27596472473a ("ipv6: fix ECMP route replacement") Signed-off-by: Benjamin Poirier Reviewed-by: Michal Kubecek Reviewed-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/route.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index f8fe4c9..9c36a74 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -4514,6 +4514,7 @@ static int ip6_route_multipath_add(struct fib6_config *cfg, */ cfg->fc_nlinfo.nlh->nlmsg_flags &= ~(NLM_F_EXCL | NLM_F_REPLACE); + cfg->fc_nlinfo.nlh->nlmsg_flags |= NLM_F_CREATE; nhn++; } -- 2.7.4