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[net,v3,1/2] ipv6: do not delete previously existing ECMP routes if add fails

Message ID 424c88b76fd2470d5e8c8f74b8ea6a72b6640fab.1431974706.git.mkubecek@suse.cz
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Michal Kubecek May 18, 2015, 6:53 p.m. UTC
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: 51ebd3181572 ("ipv6: add support of equal cost multipath (ECMP)")
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
---
 net/ipv6/route.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
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Patch

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index d3588885f097..3821a3517478 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -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;
 			}
 		}