peer_control: always keep gossip_client_fd.

This is simpler than passing back and forth, for the moment at least.  That
means we don't need to ask for a new one on reconnect.

This partially reverts the gossip handling in openingd, since it no longer
passes the gossip fd back.  We also close it when peer is freed, so it
needs initializing to -1.

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

lightningd/opening/opening.c

@@ -738,11 +738,10 @@ int main(int argc, char *argv[])
 				   minimum_depth, min_feerate, max_feerate,
 				   peer_msg);
 
-	/* Write message and hand back the peer fd ang gossip fd. */
+	/* Write message and hand back the fd. */
 	wire_sync_write(REQ_FD, msg);
 	fdpass_send(REQ_FD, PEER_FD);
-	fdpass_send(REQ_FD, GOSSIP_FD);
-	status_trace("Sent %s with 2 fds",
+	status_trace("Sent %s with fd",
 		     opening_wire_type_name(fromwire_peektype(msg)));
 	tal_free(state);
 	return 0;

lightningd/peer_control.c

@@ -49,6 +49,8 @@ static void destroy_peer(struct peer *peer)
 	list_del_from(&peer->ld->peers, &peer->list);
 	if (peer->fd >= 0)
 		close(peer->fd);
+	if (peer->gossip_client_fd >= 0)
+		close(peer->gossip_client_fd);
 }
 
 static struct peer *peer_by_pubkey(struct lightningd *ld, const struct pubkey *id)
@@ -168,6 +170,9 @@ static bool peer_reconnected(struct lightningd *ld,
 	tal_free(peer->cs);
 	peer->cs = tal_dup(peer, struct crypto_state, cs);
 
+	/* FIXME: We should close peer->gossip_client_fd when we're not
+	 * connected, and get a new one from gossipd when we reconnect. */
+
 	switch (peer->state) {
 	/* This can't happen. */
 	case UNINITIALIZED:
@@ -284,6 +289,7 @@ void add_peer(struct lightningd *ld, u64 unique_id,
 	peer->scid = NULL;
 	peer->id = tal_dup(peer, struct pubkey, id);
 	peer->fd = fd;
+	peer->gossip_client_fd = -1;
 	peer->cs = tal_dup(peer, struct crypto_state, cs);
 	peer->funding_txid = NULL;
 	peer->seed = NULL;
@@ -1503,7 +1509,7 @@ static bool peer_start_channeld_hsmfd(struct subd *hsm, const u8 *resp,
 			       channel_msg,
 			       peer_owner_finished,
 			       take(&peer->fd),
-			       take(&peer->gossip_client_fd),
+			       &peer->gossip_client_fd,
 			       take(&fds[0]), NULL);
 	if (!peer->owner) {
 		log_unusual(peer->log, "Could not subdaemon channel: %s",
@@ -1579,9 +1585,8 @@ static bool opening_funder_finished(struct subd *opening, const u8 *resp,
 	struct pubkey changekey;
 	struct pubkey local_fundingkey;
 
-	assert(tal_count(fds) == 2);
+	assert(tal_count(fds) == 1);
 	fc->peer->fd = fds[0];
-	fc->peer->gossip_client_fd = fds[1];
 	fc->peer->cs = tal(fc->peer, struct crypto_state);
 
 	/* At this point, we care about peer */
@@ -1664,9 +1669,8 @@ static bool opening_fundee_finished(struct subd *opening,
 	struct channel_info *channel_info;
 
 	log_debug(peer->log, "Got opening_fundee_finish_response");
-	assert(tal_count(fds) == 2);
+	assert(tal_count(fds) == 1);
 	peer->fd = fds[0];
-	peer->gossip_client_fd = fds[1];
 	peer->cs = tal(peer, struct crypto_state);
 
 	/* At this point, we care about peer */
@@ -1778,7 +1782,7 @@ void peer_fundee_open(struct peer *peer, const u8 *from_peer)
 	peer->owner = new_subd(ld, ld, "lightningd_opening", peer,
 			       opening_wire_type_name,
 			       NULL, peer_owner_finished,
-			       take(&peer->fd), take(&peer->gossip_client_fd),
+			       take(&peer->fd), &peer->gossip_client_fd,
 			       NULL);
 	if (!peer->owner) {
 		peer_fail(peer, "Failed to subdaemon opening: %s",
@@ -1817,7 +1821,7 @@ void peer_fundee_open(struct peer *peer, const u8 *from_peer)
 		peer_fail(peer, "Unacceptably long open_channel");
 		return;
 	}
-	subd_req(peer, peer->owner, take(msg), -1, 2,
+	subd_req(peer, peer->owner, take(msg), -1, 1,
 		 opening_fundee_finished, peer);
 }
 
@@ -1861,7 +1865,7 @@ static bool gossip_peer_released(struct subd *gossip,
 			   opening_wire_type_name,
 			   NULL, peer_owner_finished,
 			   take(&fc->peer->fd),
-			   take(&fc->peer->gossip_client_fd), NULL);
+			   &fc->peer->gossip_client_fd, NULL);
 	if (!opening) {
 		peer_fail(fc->peer, "Failed to subdaemon opening: %s",
 			  strerror(errno));
@@ -1899,7 +1903,7 @@ static bool gossip_peer_released(struct subd *gossip,
 				    15000, max_minimum_depth,
 				    fc->change, fc->change_keyindex,
 				    utxos, bip32_base);
-	subd_req(fc, opening, take(msg), -1, 2, opening_funder_finished, fc);
+	subd_req(fc, opening, take(msg), -1, 1, opening_funder_finished, fc);
 	return true;
 }