diff options
author | Stephen Suryaputra Lin <stephen.suryaputra.lin@gmail.com> | 2016-11-10 11:16:15 -0500 |
---|---|---|
committer | Willy Tarreau <w@1wt.eu> | 2017-02-10 11:03:55 +0100 |
commit | 3816ef445e2b4762c6242b672b5bf72ec2bed7a9 (patch) | |
tree | d1cd580c0e6b8e49825ff6cc6436c59c98e79b06 | |
parent | 4d4c1fc6258af913f0a9a9595f2385e58f9f1d9a (diff) | |
download | linux-stable-3816ef445e2b4762c6242b672b5bf72ec2bed7a9.tar.gz linux-stable-3816ef445e2b4762c6242b672b5bf72ec2bed7a9.tar.bz2 linux-stable-3816ef445e2b4762c6242b672b5bf72ec2bed7a9.zip |
ipv4: use new_gw for redirect neigh lookup
commit 969447f226b451c453ddc83cac6144eaeac6f2e3 upstream.
In v2.6, ip_rt_redirect() calls arp_bind_neighbour() which returns 0
and then the state of the neigh for the new_gw is checked. If the state
isn't valid then the redirected route is deleted. This behavior is
maintained up to v3.5.7 by check_peer_redirect() because rt->rt_gateway
is assigned to peer->redirect_learned.a4 before calling
ipv4_neigh_lookup().
After commit 5943634fc559 ("ipv4: Maintain redirect and PMTU info in
struct rtable again."), ipv4_neigh_lookup() is performed without the
rt_gateway assigned to the new_gw. In the case when rt_gateway (old_gw)
isn't zero, the function uses it as the key. The neigh is most likely
valid since the old_gw is the one that sends the ICMP redirect message.
Then the new_gw is assigned to fib_nh_exception. The problem is: the
new_gw ARP may never gets resolved and the traffic is blackholed.
So, use the new_gw for neigh lookup.
Changes from v1:
- use __ipv4_neigh_lookup instead (per Eric Dumazet).
Fixes: 5943634fc559 ("ipv4: Maintain redirect and PMTU info in struct rtable again.")
Signed-off-by: Stephen Suryaputra Lin <ssurya@ieee.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
-rw-r--r-- | net/ipv4/route.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index cbad9b896c75..e59d6332458b 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -713,7 +713,9 @@ static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flow goto reject_redirect; } - n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw); + n = __ipv4_neigh_lookup(rt->dst.dev, new_gw); + if (!n) + n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); if (!IS_ERR(n)) { if (!(n->nud_state & NUD_VALID)) { neigh_event_send(n, NULL); |