subd: handle status_peer_billboard messages from subdaemons.

We use a callback which updates the appropriate slot.

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

common/status_wire.csv

@@ -15,4 +15,7 @@ status_fail,,desc,wirestring
 
 status_peer_connection_lost,0xFFF3
 
+status_peer_billboard,0xFFF5
+status_peer_billboard,,perm,bool
+status_peer_billboard,,happenings,wirestring
 # Note: 0xFFFF is reserved for MSG_PASS_FD!

lightningd/channel_control.c

@@ -238,6 +238,7 @@ bool peer_start_channeld(struct channel *channel,
 					   channel_wire_type_name,
 					   channel_msg,
 					   channel_errmsg,
+					   channel_set_billboard,
 					   take(&peer_fd),
 					   take(&gossip_fd),
 					   take(&hsmfd), NULL));

lightningd/closing_control.c

@@ -163,6 +163,7 @@ void peer_start_closingd(struct channel *channel,
 					   channel, channel->log,
 					   closing_wire_type_name, closing_msg,
 					   channel_errmsg,
+					   channel_set_billboard,
 					   take(&peer_fd), take(&gossip_fd),
 					   NULL));
 	if (!channel->owner) {

lightningd/onchain_control.c

@@ -372,6 +372,7 @@ enum watch_result funding_spent(struct channel *channel,
 						    onchain_wire_type_name,
 						    onchain_msg,
 						    onchain_error,
+						    channel_set_billboard,
 						    NULL));
 
 	if (!channel->owner) {

lightningd/opening_control.c

@@ -485,6 +485,15 @@ static void opening_channel_errmsg(struct uncommitted_channel *uc,
 	tal_free(uc);
 }
 
+/* There's nothing permanent in an unconfirmed transaction */
+static void opening_channel_set_billboard(struct uncommitted_channel *uc,
+					  bool perm UNUSED,
+					  const char *happenings TAKES)
+{
+	tal_free(uc->transient_billboard);
+	uc->transient_billboard = tal_strdup(uc, happenings);
+}
+
 static void destroy_uncommitted_channel(struct uncommitted_channel *uc)
 {
 	uc->peer->uncommitted_channel = NULL;
@@ -607,6 +616,7 @@ u8 *peer_accept_channel(struct lightningd *ld,
 	uc->openingd = new_channel_subd(ld, "lightning_openingd", uc, uc->log,
 					opening_wire_type_name,	NULL,
 					opening_channel_errmsg,
+					opening_channel_set_billboard,
 					take(&peer_fd), take(&gossip_fd),
 					NULL);
 	if (!uc->openingd) {
@@ -692,6 +702,7 @@ static void peer_offer_channel(struct lightningd *ld,
 				    "lightning_openingd", fc->uc, fc->uc->log,
 				    opening_wire_type_name, NULL,
 				    opening_channel_errmsg,
+				    opening_channel_set_billboard,
 				    take(&peer_fd), take(&gossip_fd),
 				    NULL);
 	if (!fc->uc->openingd) {

lightningd/subd.c

@@ -413,6 +413,18 @@ static bool handle_peer_error(struct subd *sd, const u8 *msg, int fds[2])
 	return true;
 }
 
+static bool handle_set_billboard(struct subd *sd, const u8 *msg)
+{
+	bool perm;
+	char *happenings;
+
+	if (!fromwire_status_peer_billboard(msg, msg, &perm, &happenings))
+		return false;
+
+	sd->billboardcb(sd->channel, perm, happenings);
+	return true;
+}
+
 static struct io_plan *sd_msg_read(struct io_conn *conn, struct subd *sd)
 {
 	int type = fromwire_peektype(sd->msg_in);
@@ -460,6 +472,12 @@ static struct io_plan *sd_msg_read(struct io_conn *conn, struct subd *sd)
 			goto malformed;
 		log_info(sd->log, "Peer connection lost");
 		goto close;
+	case WIRE_STATUS_PEER_BILLBOARD:
+		if (!sd->channel)
+			goto malformed;
+		if (!handle_set_billboard(sd, sd->msg_in))
+			goto malformed;
+		goto next;
 	}
 
 	if (sd->channel) {
@@ -629,6 +647,9 @@ static struct subd *new_subd(struct lightningd *ld,
 					   const struct channel_id *channel_id,
 					   const char *desc,
 					   const u8 *err_for_them),
+			     void (*billboardcb)(void *channel,
+						 bool perm,
+						 const char *happenings),
 			     va_list *ap)
 {
 	struct subd *sd = tal(ld, struct subd);
@@ -661,6 +682,7 @@ static struct subd *new_subd(struct lightningd *ld,
 	sd->msgname = msgname;
 	sd->msgcb = msgcb;
 	sd->errcb = errcb;
+	sd->billboardcb = billboardcb;
 	sd->fds_in = NULL;
 	msg_queue_init(&sd->outq, sd);
 	tal_add_destructor(sd, destroy_subd);
@@ -687,7 +709,7 @@ struct subd *new_global_subd(struct lightningd *ld,
 	struct subd *sd;
 
 	va_start(ap, msgcb);
-	sd = new_subd(ld, name, NULL, NULL, msgname, msgcb, NULL, &ap);
+	sd = new_subd(ld, name, NULL, NULL, msgname, msgcb, NULL, NULL, &ap);
 	va_end(ap);
 
 	sd->must_not_exit = true;
@@ -708,13 +730,16 @@ struct subd *new_channel_subd_(struct lightningd *ld,
 					     const struct channel_id *channel_id,
 					     const char *desc,
 					     const u8 *err_for_them),
+			       void (*billboardcb)(void *channel, bool perm,
+						   const char *happenings),
 			       ...)
 {
 	va_list ap;
 	struct subd *sd;
 
-	va_start(ap, errcb);
-	sd = new_subd(ld, name, channel, base_log, msgname, msgcb, errcb, &ap);
+	va_start(ap, billboardcb);
+	sd = new_subd(ld, name, channel, base_log, msgname,
+		      msgcb, errcb, billboardcb, &ap);
 	va_end(ap);
 	return sd;
 }

lightningd/subd.h

@@ -48,6 +48,9 @@ struct subd {
 		      const char *desc,
 		      const u8 *err_for_them);
 
+	/* Callback to display information for listpeers RPC */
+	void (*billboardcb)(void *channel, bool perm, const char *happenings);
+
 	/* Buffer for input. */
 	u8 *msg_in;
 
@@ -93,6 +96,8 @@ struct subd *new_global_subd(struct lightningd *ld,
  * @base_log: log to use (actually makes a copy so it has name in prefix)
  * @msgname: function to get name from messages
  * @msgcb: function to call (inside db transaction) when non-fatal message received (or NULL)
+ * @errcb: function to call on errors.
+ * @billboardcb: function to call for billboard updates.
  * @...: NULL-terminated list of pointers to  fds to hand as fd 3, 4...
  *	(can be take, if so, set to -1)
  *
@@ -114,9 +119,12 @@ struct subd *new_channel_subd_(struct lightningd *ld,
 					     const struct channel_id *channel_id,
 					     const char *desc,
 					     const u8 *err_for_them),
+			       void (*billboardcb)(void *channel, bool perm,
+						   const char *happenings),
 			       ...);
 
-#define new_channel_subd(ld, name, channel, log, msgname, msgcb, errcb, ...) \
+#define new_channel_subd(ld, name, channel, log, msgname, \
+			 msgcb, errcb, billboardcb, ...)		\
 	new_channel_subd_((ld), (name), (channel), (log), (msgname), (msgcb), \
 			  typesafe_cb_postargs(void, void *, (errcb),	\
 					       (channel), int, int,	\
@@ -124,6 +132,9 @@ struct subd *new_channel_subd_(struct lightningd *ld,
 					       u64,			\
 					       const struct channel_id *, \
 					       const char *, const u8 *), \
+			  typesafe_cb_postargs(void, void *, (billboardcb), \
+					       (channel), bool,		\
+					       const char *),		\
 			  __VA_ARGS__)
 /**
  * subd_raw - raw interface to get a subdaemon on an fd (for HSM)