Re: [PATCH net] ipv6: Do not consider linkdown nexthops during multipath
From: Andy Gospodarek <andy@greyhouse.net>
Date: 2017-11-21 19:12:03
On Tue, Nov 21, 2017 at 09:50:12AM +0200, Ido Schimmel wrote:
When the 'ignore_routes_with_linkdown' sysctl is set, we should not
consider linkdown nexthops during route lookup.
While the code correctly verifies that the initially selected route
('match') has a carrier, it does not perform the same check in the
subsequent multipath selection, resulting in a potential packet loss.
In case the chosen route does not have a carrier and the sysctl is set,
choose the initially selected route.
Fixes: 35103d11173b ("net: ipv6 sysctl option to ignore routes when nexthop link is down")
Signed-off-by: Ido Schimmel <redacted>Nice find. Looks good to me, as well. Acked-by: Andy Gospodarek <andy@greyhouse.net>
quoted hunk ↗ jump to hunk
--- net/ipv6/route.c | 5 +++++ 1 file changed, 5 insertions(+)diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 05eb7bc36156..0363db914c7a 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c@@ -472,6 +472,11 @@ static struct rt6_info *rt6_multipath_select(struct rt6_info *match, &match->rt6i_siblings, rt6i_siblings) { route_choosen--; if (route_choosen == 0) { + struct inet6_dev *idev = sibling->rt6i_idev; + + if (!netif_carrier_ok(sibling->dst.dev) && + idev->cnf.ignore_routes_with_linkdown) + break; if (rt6_score_route(sibling, oif, strict) < 0) break; match = sibling;-- 2.14.3