Remember forwarded requests, satisfy them later.

destination.c

@@ -58,6 +58,8 @@ find_destination(const unsigned char *d, int create, unsigned char seqno)
     dests[i].seqno = seqno;
     dests[i].metric = INFINITY;
     dests[i].time = now.tv_sec;
+    dests[i].requested_seqno = -1;
+    dests[i].requested_net = NULL;
     return &dests[i];
 }
 
@@ -73,3 +75,47 @@ update_destination(struct destination *dest,
     dest->time = now.tv_sec;
 }
 
+void
+notice_request(struct destination *dest, unsigned char seqno,
+               struct network *net)
+{
+    if(dest->requested_seqno < 0) {
+        dest->requested_seqno = seqno;
+        dest->requested_net = net;
+    } else {
+        if(seqno_compare(dest->requested_seqno, seqno) < 0)
+            dest->requested_seqno = seqno;
+        if(net == NULL || net != dest->requested_net)
+            dest->requested_net = NULL;
+    }
+}
+
+int
+request_requested(struct destination *dest, unsigned char seqno,
+                  struct network *net)
+{
+    if(dest->requested_seqno < 0)
+        return 0;
+
+    if(seqno_compare(dest->requested_seqno, seqno) < 0)
+        return 0;
+
+    if(net == NULL || net != dest->requested_net)
+        return 0;
+
+    return 1;
+}
+
+void
+satisfy_request(struct destination *dest, unsigned char seqno,
+                struct network *net)
+{
+    if(dest->requested_seqno >= 0) {
+        if(net == NULL || net == dest->requested_net) {
+            if(seqno_compare(seqno, dest->requested_seqno) >= 0) {
+                dest->requested_seqno = -1;
+                dest->requested_net = NULL;
+            }
+        }
+    }
+}

destination.h

@@ -25,9 +25,17 @@ struct destination {
     unsigned char seqno;
     unsigned short metric;
     int time;
+    int requested_seqno;
+    struct network *requested_net;
 };
 
 struct destination *find_destination(const unsigned char *d,
                                      int create, unsigned char seqno);
 void update_destination(struct destination *dest,
                         unsigned char seqno, unsigned short metric);
+void notice_request(struct destination *dest, unsigned char seqno,
+                    struct network *net);
+int request_requested(struct destination *dest, unsigned char seqno,
+                      struct network *net);
+void satisfy_request(struct destination *dest, unsigned char seqno,
+                     struct network *net);

message.c

@@ -144,14 +144,16 @@ parse_packet(const unsigned char *from, struct network *net,
                                 if(seqno_compare(installed->seqno,
                                                  theirseqno) >= 0)
                                     send_update(dest, neigh->network);
-                                else if(hopcount >= 2) {
-                                    send_unicast_request(installed->nexthop,
-                                                         dest,
-                                                         hopcount - 1,
-                                                         theirseqno);
-                                    /* For now, let's hope the new seqno
-                                       arrives before the update is flushed. */
-                                    send_update(dest, neigh->network);
+                                else if(!request_requested(dest,
+                                                           theirseqno,
+                                                           neigh->network)) {
+                                    if(hopcount >= 2)
+                                        send_unicast_request(installed->nexthop,
+                                                             dest,
+                                                             hopcount - 1,
+                                                             theirseqno);
+                                    notice_request(dest, theirseqno,
+                                                   neigh->network);
                                 }
                             }
                         }
@@ -530,6 +532,7 @@ flushupdates(void)
                 accumulate_byte(net, seqno);
                 accumulate_short(net, metric);
                 accumulate_data(net, buffered_updates[i]->address, 16);
+                satisfy_request(buffered_updates[i], seqno, net);
             }
         }
         schedule_flush_now(net);
@@ -578,6 +581,12 @@ send_update(struct destination *dest, struct network *net)
     if(net == NULL) {
         for(i = 0; i < numnets; i++)
             send_update(dest, &nets[i]);
+        if(dest != NULL) {
+            /* This case is not handled by flushupdates. */
+            struct route *installed = find_installed_route(dest);
+            satisfy_request(dest, installed ? installed->seqno : dest->seqno,
+                            NULL);
+        }
         return;
     }
 

route.c

@@ -428,6 +428,9 @@ send_triggered_update(struct route *route, int oldmetric)
     if((route->metric >= INFINITY && oldmetric < INFINITY) ||
        (route->metric - oldmetric >= 256 || oldmetric - route->metric >= 256))
         send_update(route->dest, NULL);
+    else if(route->dest->requested_seqno >= 0 &&
+            seqno_compare(route->dest->requested_seqno, route->seqno) <= 0)
+        send_update(route->dest, route->dest->requested_net);
 
     if(oldmetric < INFINITY) {
         if(route->metric >= INFINITY) {