[NETNS]: Lookup in FIB semantic hashes taking into account the namespace.

The namespace is not available in the fib_sync_down_addr, add it as a
parameter.

Looking up a device by the pointer to it is OK. Looking up using a
result from fib_trie/fib_hash table lookup is also safe. No need to
fix that at all.  So, just fix lookup by address and insertion to the
hash table path.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip_fib.h

@@ -220,7 +220,7 @@ extern void fib_select_default(struct net *net, const struct flowi *flp,
 /* Exported by fib_semantics.c */
 extern int ip_fib_check_default(__be32 gw, struct net_device *dev);
 extern int fib_sync_down_dev(struct net_device *dev, int force);
-extern int fib_sync_down_addr(__be32 local);
+extern int fib_sync_down_addr(struct net *net, __be32 local);
 extern int fib_sync_up(struct net_device *dev);
 extern __be32  __fib_res_prefsrc(struct fib_result *res);
 extern void fib_select_multipath(const struct flowi *flp, struct fib_result *res);

net/ipv4/fib_frontend.c

@@ -808,7 +808,7 @@ static void fib_del_ifaddr(struct in_ifaddr *ifa)
 			   First of all, we scan fib_info list searching
 			   for stray nexthop entries, then ignite fib_flush.
 			*/
-			if (fib_sync_down_addr(ifa->ifa_local))
+			if (fib_sync_down_addr(dev->nd_net, ifa->ifa_local))
 				fib_flush(dev->nd_net);
 		}
 	}

net/ipv4/fib_semantics.c

@@ -229,6 +229,8 @@ static struct fib_info *fib_find_info(const struct fib_info *nfi)
 	head = &fib_info_hash[hash];
 
 	hlist_for_each_entry(fi, node, head, fib_hash) {
+		if (fi->fib_net != nfi->fib_net)
+			continue;
 		if (fi->fib_nhs != nfi->fib_nhs)
 			continue;
 		if (nfi->fib_protocol == fi->fib_protocol &&
@@ -1031,7 +1033,7 @@ nla_put_failure:
      referring to it.
    - device went down -> we must shutdown all nexthops going via it.
  */
-int fib_sync_down_addr(__be32 local)
+int fib_sync_down_addr(struct net *net, __be32 local)
 {
 	int ret = 0;
 	unsigned int hash = fib_laddr_hashfn(local);
@@ -1043,6 +1045,8 @@ int fib_sync_down_addr(__be32 local)
 		return 0;
 
 	hlist_for_each_entry(fi, node, head, fib_lhash) {
+		if (fi->fib_net != net)
+			continue;
 		if (fi->fib_prefsrc == local) {
 			fi->fib_flags |= RTNH_F_DEAD;
 			ret++;