[DECNET]: Only use local routers

The attached patch makes DECnet routing only use routers from the same
area - rather than the highest rated router seen.

In theory there should not be an out-of-area router on a local network
but some networks are bridged rather than properly routed. VMS seems
to behave similarly: if I bring up a VMS node with no router then it
can't see anything else on the global network.

Signed-off-by: Patrick Caulfield <patrick@tykepenguin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/decnet/dn_neigh.c b/net/decnet/dn_neigh.c
index 8d0cc3c..33ab256 100644 (file)
--- a/net/decnet/dn_neigh.c
+++ b/net/decnet/dn_neigh.c
@@ -408,11 +408,14 @@ int dn_neigh_router_hello(struct sk_buff *skb)
                        }
                }
 
-               if (!dn_db->router) {
-                       dn_db->router = neigh_clone(neigh);
-               } else {
-                       if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
-                               neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
+               /* Only use routers in our area */
+               if ((dn_ntohs(src)>>10) == dn_ntohs((decnet_address)>>10)) {
+                       if (!dn_db->router) {
+                               dn_db->router = neigh_clone(neigh);
+                       } else {
+                               if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
+                                       neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
+                       }
                }
                write_unlock(&neigh->lock);
                neigh_release(neigh);