routing: Add tracking of eviction for broadcasts

We should never be evicting channel_announcements because a) they were
deeply buried and should not change the short_channel_id/tag, b) they
are static.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

gossipd/broadcast.c

@@ -21,13 +21,14 @@ static struct queued_message *new_queued_message(tal_t *ctx,
 	return msg;
 }
 
-void queue_broadcast(struct broadcast_state *bstate,
+bool queue_broadcast(struct broadcast_state *bstate,
 		     const int type,
 		     const u8 *tag,
 		     const u8 *payload)
 {
 	struct queued_message *msg;
 	u64 index;
+	bool evicted = false;
 
 	/* Remove any tag&type collisions */
 	for (msg = uintmap_first(&bstate->broadcasts, &index);
@@ -36,6 +37,8 @@ void queue_broadcast(struct broadcast_state *bstate,
 		if (msg->type == type && memcmp(msg->tag, tag, tal_count(tag)) == 0) {
 			uintmap_del(&bstate->broadcasts, index);
 			tal_free(msg);
+			evicted = true;
+			break;
 		}
 	}
 
@@ -43,6 +46,7 @@ void queue_broadcast(struct broadcast_state *bstate,
 	msg = new_queued_message(bstate, type, tag, payload);
 	uintmap_add(&bstate->broadcasts, bstate->next_index, msg);
 	bstate->next_index += 1;
+	return evicted;
 }
 
 struct queued_message *next_broadcast_message(struct broadcast_state *bstate, u64 last_index)

gossipd/broadcast.h

@@ -29,8 +29,9 @@ struct broadcast_state *new_broadcast_state(tal_t *ctx);
 /* Queue a new message to be broadcast and replace any outdated
  * broadcast. Replacement is done by comparing the `type` and the
  * `tag`, if both match the old message is dropped from the queue. The
- * new message is added to the top of the broadcast queue. */
-void queue_broadcast(struct broadcast_state *bstate,
+ * new message is added to the top of the broadcast queue. Returns
+ * true if a previous entry with the same tag has been evicted. */
+bool queue_broadcast(struct broadcast_state *bstate,
 			     const int type,
 			     const u8 *tag,
 			     const u8 *payload);

gossipd/routing.c

@@ -580,8 +580,8 @@ bool handle_channel_announcement(
 
 	u8 *tag = tal_arr(tmpctx, u8, 0);
 	towire_short_channel_id(&tag, &short_channel_id);
-	queue_broadcast(rstate->broadcasts, WIRE_CHANNEL_ANNOUNCEMENT,
-			tag, serialized);
+	assert(!queue_broadcast(rstate->broadcasts, WIRE_CHANNEL_ANNOUNCEMENT,
+				tag, serialized));
 
 	tal_free(tmpctx);
 	return local;

gossipd/test/run-bench-find_route.c

@@ -64,7 +64,7 @@ u8 fromwire_u8(const u8 **cursor UNNEEDED, size_t *max UNNEEDED)
 bool fromwire_wireaddr(const u8 **cursor UNNEEDED, size_t *max UNNEEDED, struct wireaddr *addr UNNEEDED)
 { fprintf(stderr, "fromwire_wireaddr called!\n"); abort(); }
 /* Generated stub for queue_broadcast */
-void queue_broadcast(struct broadcast_state *bstate UNNEEDED,
+bool queue_broadcast(struct broadcast_state *bstate UNNEEDED,
 			     const int type UNNEEDED,
 			     const u8 *tag UNNEEDED,
 			     const u8 *payload UNNEEDED)

gossipd/test/run-find_route-specific.c

@@ -35,7 +35,7 @@ u8 fromwire_u8(const u8 **cursor UNNEEDED, size_t *max UNNEEDED)
 bool fromwire_wireaddr(const u8 **cursor UNNEEDED, size_t *max UNNEEDED, struct wireaddr *addr UNNEEDED)
 { fprintf(stderr, "fromwire_wireaddr called!\n"); abort(); }
 /* Generated stub for queue_broadcast */
-void queue_broadcast(struct broadcast_state *bstate UNNEEDED,
+bool queue_broadcast(struct broadcast_state *bstate UNNEEDED,
 			     const int type UNNEEDED,
 			     const u8 *tag UNNEEDED,
 			     const u8 *payload UNNEEDED)

gossipd/test/run-find_route.c

@@ -28,7 +28,7 @@ u8 fromwire_u8(const u8 **cursor UNNEEDED, size_t *max UNNEEDED)
 bool fromwire_wireaddr(const u8 **cursor UNNEEDED, size_t *max UNNEEDED, struct wireaddr *addr UNNEEDED)
 { fprintf(stderr, "fromwire_wireaddr called!\n"); abort(); }
 /* Generated stub for queue_broadcast */
-void queue_broadcast(struct broadcast_state *bstate UNNEEDED,
+bool queue_broadcast(struct broadcast_state *bstate UNNEEDED,
 			     const int type UNNEEDED,
 			     const u8 *tag UNNEEDED,
 			     const u8 *payload UNNEEDED)