ipv6: If neigh lookup fails during icmp6 dst allocation, propagate error.

Don't just succeed with a route that has a NULL neighbour attached.
This follows the behavior of addrconf_dst_alloc().

Allowing this kind of route to end up with a NULL neigh attached will
result in packet drops on output until the route is somehow
invalidated, since nothing will meanwhile try to lookup the neigh
again.

A statistic is bumped for the case where we see a neigh-less route on
output, but the resulting packet drop is otherwise silent in nature,
and frankly it's a hard error for this to happen and ipv6 should do
what ipv4 does which is say something in the kernel logs.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2011-12-13 16:48:21 -05:00
parent 5c3ddec73d
commit b43faac690

View File

@ -1089,8 +1089,10 @@ struct dst_entry *icmp6_dst_alloc(struct net_device *dev,
neigh_hold(neigh);
else {
neigh = __neigh_lookup_errno(&nd_tbl, &fl6->daddr, dev);
if (IS_ERR(neigh))
neigh = NULL;
if (IS_ERR(neigh)) {
dst_free(&rt->dst);
return ERR_CAST(neigh);
}
}
rt->dst.flags |= DST_HOST;