seeker: handle non-synced state internally.

We weren't supposed to do any gossiping until we were synced (and thus
knew blockheight), but our seeker_check() didn't wait for it!  Move the
waiting all into seeker.c, so it can handle it all consistently.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

gossipd/gossipd.c

@@ -577,8 +577,7 @@ static struct io_plan *connectd_new_peer(struct io_conn *conn,
 	/* Free peer if conn closed (destroy_peer closes conn if peer freed) */
 	tal_steal(peer->dc, peer);
 
-	/* This sends the initial timestamp filter (wait until we're synced!). */
+	/* This sends the initial timestamp filter. */
-	if (daemon->current_blockheight)
 	seeker_setup_peer_gossip(daemon->seeker, peer);
 
 	/* BOLT #7:
@@ -1241,8 +1240,6 @@ static struct io_plan *new_blockheight(struct io_conn *conn,
 				       struct daemon *daemon,
 				       const u8 *msg)
 {
-	bool was_unknown = (daemon->current_blockheight == 0);
-
 	if (!fromwire_gossip_new_blockheight(msg, &daemon->current_blockheight))
 		master_badmsg(WIRE_GOSSIP_NEW_BLOCKHEIGHT, msg);
 
@@ -1263,14 +1260,6 @@ static struct io_plan *new_blockheight(struct io_conn *conn,
 		i--;
 	}
 
-	/* Do we need to start gossip filtering now? */
-	if (was_unknown) {
-		struct peer *peer;
-
-		list_for_each(&daemon->peers, peer, list)
-			seeker_setup_peer_gossip(daemon->seeker, peer);
-	}
-
 	return daemon_conn_read_next(conn, daemon->master);
 }
 

gossipd/seeker.c

@@ -902,9 +902,13 @@ static void seeker_check(struct seeker *seeker)
 {
 #if DEVELOPER
 	if (dev_suppress_gossip)
-		return;
+		goto out;
 #endif
 
+	/* We don't do anything until we're synced. */
+	if (seeker->daemon->current_blockheight == 0)
+		goto out;
+
 	switch (seeker->state) {
 	case STARTING_UP:
 		check_firstpeer(seeker);
@@ -929,6 +933,7 @@ static void seeker_check(struct seeker *seeker)
 		break;
 	}
 
+out:
 	begin_check_timer(seeker);
 }
 
@@ -943,6 +948,9 @@ void seeker_setup_peer_gossip(struct seeker *seeker, struct peer *peer)
 	if (dev_suppress_gossip)
 		return;
 #endif
+	/* Don't start gossiping until we're synced. */
+	if (seeker->daemon->current_blockheight == 0)
+		return;
 
 	switch (seeker->state) {
 	case STARTING_UP: