From a1a22c12060e4b9c52f45d4b3460f614e00162a2 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Wed, 18 Jan 2017 07:40:36 -0800 Subject: [PATCH] net: ipv6: Keep nexthop of multipath route on admin down IPv6 deletes route entries associated with multipath routes on an admin down where IPv4 does not. For example: $ ip ro ls vrf red unreachable default metric 8192 1.1.1.0/24 metric 64 nexthop via 10.100.1.254 dev eth1 weight 1 nexthop via 10.100.2.254 dev eth2 weight 1 10.100.1.0/24 dev eth1 proto kernel scope link src 10.100.1.4 10.100.2.0/24 dev eth2 proto kernel scope link src 10.100.2.4 $ ip -6 ro ls vrf red 2001:db8:1::/120 dev eth1 proto kernel metric 256 pref medium 2001:db8:2:: dev red proto none metric 0 pref medium 2001:db8:2::/120 dev eth2 proto kernel metric 256 pref medium 2001:db8:11::/120 via 2001:db8:1::16 dev eth1 metric 1024 pref medium 2001:db8:11::/120 via 2001:db8:2::17 dev eth2 metric 1024 pref medium ... Set link down: $ ip li set eth1 down IPv4 retains the multihop route but flags eth1 route as dead: $ ip ro ls vrf red unreachable default metric 8192 1.1.1.0/24 nexthop via 10.100.1.16 dev eth1 weight 1 dead linkdown nexthop via 10.100.2.16 dev eth2 weight 1 10.100.2.0/24 dev eth2 proto kernel scope link src 10.100.2.4 and IPv6 deletes the route as part of flushing all routes for the device: $ ip -6 ro ls vrf red 2001:db8:2:: dev red proto none metric 0 pref medium 2001:db8:2::/120 dev eth2 proto kernel metric 256 pref medium 2001:db8:11::/120 via 2001:db8:2::17 dev eth2 metric 1024 pref medium ... Worse, on admin up of the device the multipath route has to be deleted to get this leg of the route re-added. This patch keeps routes that are part of a multipath route if ignore_routes_with_linkdown is set with the dead and linkdown flags enabling consistency between IPv4 and IPv6: $ ip -6 ro ls vrf red 2001:db8:2:: dev red proto none metric 0 pref medium 2001:db8:2::/120 dev eth2 proto kernel metric 256 pref medium 2001:db8:11::/120 via 2001:db8:1::16 dev eth1 metric 1024 dead linkdown pref medium 2001:db8:11::/120 via 2001:db8:2::17 dev eth2 metric 1024 pref medium ... Signed-off-by: David Ahern Signed-off-by: David S. Miller --- net/ipv6/route.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 5585c501a540..4b1f0f98a0e9 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2711,13 +2711,16 @@ struct arg_dev_net { struct net *net; }; +/* called with write lock held for table with rt */ static int fib6_ifdown(struct rt6_info *rt, void *arg) { const struct arg_dev_net *adn = arg; const struct net_device *dev = adn->dev; if ((rt->dst.dev == dev || !dev) && - rt != adn->net->ipv6.ip6_null_entry) + rt != adn->net->ipv6.ip6_null_entry && + (rt->rt6i_nsiblings == 0 || + !rt->rt6i_idev->cnf.ignore_routes_with_linkdown)) return -1; return 0; @@ -3216,7 +3219,7 @@ static int rt6_fill_node(struct net *net, else rtm->rtm_type = RTN_UNICAST; rtm->rtm_flags = 0; - if (!netif_carrier_ok(rt->dst.dev)) { + if (!netif_running(rt->dst.dev) || !netif_carrier_ok(rt->dst.dev)) { rtm->rtm_flags |= RTNH_F_LINKDOWN; if (rt->rt6i_idev->cnf.ignore_routes_with_linkdown) rtm->rtm_flags |= RTNH_F_DEAD;