Commit 35f1b4e9 authored May 18, 2015 by Michal Kubeček Committed by David S. Miller May 20, 2015

ipv6: do not delete previously existing ECMP routes if add fails



If adding a nexthop of an IPv6 multipath route fails, comment in
ip6_route_multipath() says we are going to delete all nexthops already
added. However, current implementation deletes even the routes it
hasn't even tried to add yet. For example, running

  ip route add 1234:5678::/64 \
      nexthop via fe80::aa dev dummy1 \
      nexthop via fe80::bb dev dummy1 \
      nexthop via fe80::cc dev dummy1

twice results in removing all routes first command added.

Limit the second (delete) run to nexthops that succeeded in the first
(add) run.

Fixes: 51ebd318 ("ipv6: add support of equal cost multipath (ECMP)")
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 892bd629

net/ipv6/route.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -2504,9 +2504,9 @@ static int ip6_route_multipath(struct fib6_config *cfg, int add)
		int attrlen;
		int err = 0, last_err = 0;

		remaining = cfg->fc_mp_len;
		beginning:
		rtnh = (struct rtnexthop *)cfg->fc_mp;
		remaining = cfg->fc_mp_len;

		/* Parse a Multipath Entry */
		while (rtnh_ok(rtnh, remaining)) {
		@@ -2536,6 +2536,7 @@ beginning:
		* next hops that have been already added.
		*/
		add = 0;
		remaining = cfg->fc_mp_len - remaining;
		goto beginning;
		}
		}

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