diff options
author | Stephen Suryaputra Lin <stephen.suryaputra.lin@gmail.com> | 2016-11-10 19:16:15 +0300 |
---|---|---|
committer | Jiri Slaby <jslaby@suse.cz> | 2016-11-29 00:22:40 +0300 |
commit | 75ed3f35930e79bcb1a5e61d0520953fea3e30a2 (patch) | |
tree | 345c243186f489afa40651df1606b93ab86cba3a /include/net | |
parent | 34a6fca3d0eb6b8bdedd38ac463dc161ca6979f6 (diff) | |
download | linux-75ed3f35930e79bcb1a5e61d0520953fea3e30a2.tar.xz |
ipv4: use new_gw for redirect neigh lookup
[ Upstream commit 969447f226b451c453ddc83cac6144eaeac6f2e3 ]
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: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'include/net')
0 files changed, 0 insertions, 0 deletions