Send requests when we lose a route.

When we lose a route and have no feasible alternate, we should send requests
straight away rather than waiting for a periodic update.  If we have an
unfeasible route, send according to that route and resend, otherwise do
a multicast.

message.c

@@ -2032,21 +2032,27 @@ send_unicast_multihop_request(struct neighbour *neigh,
     }
 }
 
+/* Send a request to a well-chosen neighbour and resend.  If there is no
+   good neighbour, send over multicast but only once. */
 void
-send_request_resend(struct neighbour *neigh,
-                    const unsigned char *prefix, unsigned char plen,
+send_request_resend(const unsigned char *prefix, unsigned char plen,
                     const unsigned char *src_prefix, unsigned char src_plen,
                     unsigned short seqno, unsigned char *id)
 {
-    if(neigh)
+    struct babel_route *route;
+
+    route = find_best_route(prefix, plen, src_prefix, src_plen, 0, NULL);
+
+    if(route) {
+        struct neighbour *neigh = route->neigh;
         send_unicast_multihop_request(neigh, prefix, plen, src_prefix, src_plen,
                                       seqno, id, 127);
-    else
+        record_resend(RESEND_REQUEST, prefix, plen, src_prefix, src_plen, seqno,
+                      id, neigh->ifp, resend_delay);
+    } else {
         send_multihop_request(NULL, prefix, plen, src_prefix, src_plen,
                               seqno, id, 127);
-
-    record_resend(RESEND_REQUEST, prefix, plen, src_prefix, src_plen, seqno, id,
-                  neigh ? neigh->ifp : NULL, resend_delay);
+    }
 }
 
 void

message.h

@@ -99,8 +99,7 @@ send_unicast_multihop_request(struct neighbour *neigh,
                               unsigned char src_plen,
                               unsigned short seqno, const unsigned char *id,
                               unsigned short hop_count);
-void send_request_resend(struct neighbour *neigh,
-                         const unsigned char *prefix, unsigned char plen,
+void send_request_resend(const unsigned char *prefix, unsigned char plen,
                          const unsigned char *src_prefix,
                          unsigned char src_plen,
                          unsigned short seqno, unsigned char *id);

route.c

@@ -882,9 +882,10 @@ update_route(const unsigned char *id,
 
     if(route) {
         struct source *oldsrc;
-        unsigned short oldmetric;
+        unsigned short oldmetric, oldinstalled;
         int lost = 0;
 
+        oldinstalled = route->installed;
         oldsrc = route->src;
         oldmetric = route_metric(route);
 
@@ -935,12 +936,14 @@ update_route(const unsigned char *id,
         route->hold_time = hold_time;
 
         route_changed(route, oldsrc, oldmetric);
+        if(!lost) {
+            lost = oldinstalled &&
+                find_installed_route(prefix, plen, src_prefix, src_plen) == NULL;
+        }
         if(lost)
             route_lost(oldsrc, oldmetric);
-
-        if(!feasible)
-            send_unfeasible_request(neigh, route->installed && route_old(route),
-                                    seqno, metric, src);
+        else if(!feasible)
+            send_unfeasible_request(neigh, route_old(route), seqno, metric, src);
         release_source(oldsrc);
     } else {
         struct babel_route *new_route;