peer_failed: hand fds back to master when we fail.

master now hands it back to gossipd.

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

common/peer_failed.c

@@ -33,7 +33,7 @@ void peer_failed_(int peer_fd, int gossip_fd,
 	msg = towire_status_peer_error(NULL, channel_id,
 				       desc, cs, gossip_index, msg);
 	tal_free(desc);
-	status_send_fatal(take(msg));
+	status_send_fatal(take(msg), peer_fd, gossip_fd);
 }
 
 /* We're failing because peer sent us an error message */
@@ -44,10 +44,11 @@ void peer_failed_received_errmsg(int peer_fd, int gossip_fd,
 {
 	u8 *msg = towire_status_peer_error(NULL, channel_id,
 					   desc, cs, gossip_index, NULL);
-	status_send_fatal(take(msg));
+	status_send_fatal(take(msg), peer_fd, gossip_fd);
 }
 
 void peer_failed_connection_lost(void)
 {
-	status_send_fatal(take(towire_status_peer_connection_lost(NULL)));
+	status_send_fatal(take(towire_status_peer_connection_lost(NULL)),
+			  -1, -1);
 }

common/status.c

@@ -122,12 +122,19 @@ static NORETURN void flush_and_exit(int reason)
 	exit(0x80 | (reason & 0xFF));
 }
 
-void status_send_fatal(const u8 *msg TAKES)
+void status_send_fatal(const u8 *msg TAKES, int fd1, int fd2)
 {
 	int reason = fromwire_peektype(msg);
 	breakpoint();
 	status_send(msg);
 
+	/* We don't support async fd passing here. */
+	if (fd1 != -1) {
+		assert(!status_conn);
+		fdpass_send(status_fd, fd1);
+		fdpass_send(status_fd, fd2);
+	}
+
 	flush_and_exit(reason);
 }
 
@@ -141,7 +148,8 @@ void status_failed(enum status_failreason reason, const char *fmt, ...)
 	str = tal_vfmt(NULL, fmt, ap);
 	va_end(ap);
 
-	status_send_fatal(take(towire_status_fail(NULL, reason, str)));
+	status_send_fatal(take(towire_status_fail(NULL, reason, str)),
+			  -1, -1);
 }
 
 void master_badmsg(u32 type_expected, const u8 *msg)

common/status.h

@@ -51,5 +51,5 @@ void status_failed(enum status_failreason code,
  * msg NULL == read failure. */
 void master_badmsg(u32 type_expected, const u8 *msg) NORETURN;
 
-void status_send_fatal(const u8 *msg TAKES) NORETURN;
+void status_send_fatal(const u8 *msg TAKES, int fd1, int fd2) NORETURN;
 #endif /* LIGHTNING_COMMON_STATUS_H */

lightningd/peer_control.c

@@ -364,28 +364,60 @@ static void channel_config(struct lightningd *ld,
 };
 
 static void channel_errmsg(struct channel *channel,
-			   enum side sender,
-			   const struct channel_id *channel_id,
-			   const char *desc,
-			   const u8 *errmsg)
-{
-	if (sender == LOCAL) {
-		/* If this is NULL, it means subd died. */
-		if (!errmsg) {
-			channel_fail_transient(channel, "%s: %s",
-					       channel->owner->name, desc);
-			return;
-		}
+		      int peer_fd, int gossip_fd,
+		      const struct crypto_state *cs,
+		      u64 gossip_index,
+		      const struct channel_id *channel_id,
+		      const char *desc,
+		      const u8 *err_for_them)
+{
+	struct lightningd *ld = channel->peer->ld;
+	u8 *msg;
 
-		/* Otherwise overwrite any error we have */
-		if (!channel->error)
-			channel->error = tal_dup_arr(channel, u8,
-						     errmsg, tal_len(errmsg), 0);
+	/* No peer fd means a subd crash or disconnection. */
+	if (peer_fd == -1) {
+		channel_fail_transient(channel, "%s: %s",
+				       channel->owner->name, desc);
+		return;
 	}
 
+	/* Do we have an error to send? */
+	if (err_for_them && !channel->error)
+		channel->error = tal_dup_arr(channel, u8,
+					     err_for_them,
+					     tal_len(err_for_them), 0);
+
+	/* BOLT #1:
+	 *
+	 * A sending node:
+	 *...
+	 *   - when `channel_id` is 0:
+	 *    - MUST fail all channels.
+	 *    - MUST close the connection.
+	 */
+	/* FIXME: Gossipd closes connection, but doesn't fail channels. */
+
+	/* BOLT #1:
+	 *
+	 * A sending node:
+	 *  - when sending `error`:
+	 *    - MUST fail the channel referred to by the error message.
+	 *...
+	 * The receiving node:
+	 *  - upon receiving `error`:
+	 *    - MUST fail the channel referred to by the error message.
+	 */
 	channel_fail_permanent(channel, "%s: %s ERROR %s",
 			       channel->owner->name,
-			       sender == LOCAL ? "sent" : "received", desc);
+			       err_for_them ? "sent" : "received", desc);
+
+	/* Hand back to gossipd, with any error packet. */
+	msg = towire_gossipctl_hand_back_peer(NULL, &channel->peer->id,
+					      cs, gossip_index,
+					      err_for_them);
+	subd_send_msg(ld->gossip, take(msg));
+	subd_send_fd(ld->gossip, peer_fd);
+	subd_send_fd(ld->gossip, gossip_fd);
 }
 
 /* Gossipd tells us a peer has connected */
@@ -1340,10 +1372,12 @@ static bool tell_if_missing(const struct channel *channel,
 
 /* Only error onchaind can get is if it dies. */
 static void onchain_error(struct channel *channel,
-			  enum side sender,
+			  int peer_fd, int gossip_fd,
+			  const struct crypto_state *cs,
+			  u64 gossip_index,
 			  const struct channel_id *channel_id,
 			  const char *desc,
-			  const u8 *errmsg)
+			  const u8 *err_for_them)
 {
 	/* FIXME: re-launch? */
 	log_broken(channel->log, "%s", desc);
@@ -2472,21 +2506,23 @@ static unsigned int opening_negotiation_failed(struct subd *openingd,
 	return 0;
 }
 
-/* errmsg == NULL for local if daemon died */
+/* peer_fd == -1 for local if daemon died */
 static void opening_channel_errmsg(struct uncommitted_channel *uc,
-				   enum side sender,
+				   int peer_fd, int gossip_fd,
+				   const struct crypto_state *cs,
+				   u64 gossip_index,
 				   const struct channel_id *channel_id,
 				   const char *desc,
-				   const u8 *errmsg)
+				   const u8 *err_for_them)
 {
 	if (uc->fc)
 		command_fail(uc->fc->cmd, "%sERROR %s",
-			     sender == LOCAL ? (errmsg ? "sent " : "")
-			     : "received ",
+			     peer_fd == -1 ? ""
+			     : (err_for_them ? "sent " : "received "),
 			     desc);
 
 	log_info(uc->log, "%sERROR %s",
-		 sender == LOCAL ? (errmsg ? "sent " : "") : "received ",
+		 peer_fd == -1 ? "" : (err_for_them ? "sent " : "received "),
 		 desc);
 	tal_free(uc);
 }

lightningd/subd.c

@@ -388,7 +388,7 @@ static bool log_status_fail(struct subd *sd, const u8 *msg)
 	return true;
 }
 
-static bool handle_peer_error(struct subd *sd, const u8 *msg)
+static bool handle_peer_error(struct subd *sd, const u8 *msg, int fds[2])
 {
 	void *channel = sd->channel;
 	struct channel_id channel_id;
@@ -402,11 +402,9 @@ static bool handle_peer_error(struct subd *sd, const u8 *msg)
 					&cs, &gossip_index, &err_for_them))
 		return false;
 
-	/* FIXME: hand back to gossipd! */
-
 	/* Don't free sd; we're may be about to free channel. */
 	sd->channel = NULL;
-	sd->errcb(channel, err_for_them ? LOCAL : REMOTE,
+	sd->errcb(channel, fds[0], fds[1], &cs, gossip_index,
 		  &channel_id, desc, err_for_them);
 	return true;
 }
@@ -463,7 +461,15 @@ static struct io_plan *sd_msg_read(struct io_conn *conn, struct subd *sd)
 	if (sd->channel) {
 		switch ((enum peer_status)type) {
 		case WIRE_STATUS_PEER_ERROR:
-			if (!handle_peer_error(sd, sd->msg_in))
+			/* We expect 2 fds after this */
+			if (!sd->fds_in) {
+				/* Don't free msg_in: we go around again. */
+				tal_steal(sd, sd->msg_in);
+				tal_free(tmpctx);
+				plan = sd_collect_fds(conn, sd, 2);
+				goto out;
+			}
+			if (!handle_peer_error(sd, sd->msg_in, sd->fds_in))
 				goto malformed;
 			goto close;
 		}
@@ -564,7 +570,7 @@ static void destroy_subd(struct subd *sd)
 		if (!outer_transaction)
 			db_begin_transaction(db);
 		if (sd->errcb)
-			sd->errcb(channel, LOCAL, NULL,
+			sd->errcb(channel, -1, -1, NULL, 0, NULL,
 				  tal_fmt(sd, "Owning subdaemon %s died (%i)",
 					  sd->name, status),
 				  NULL);
@@ -613,10 +619,12 @@ static struct subd *new_subd(struct lightningd *ld,
 			     unsigned int (*msgcb)(struct subd *,
 						   const u8 *, const int *fds),
 			     void (*errcb)(void *channel,
-					   enum side sender,
+					   int peer_fd, int gossip_fd,
+					   const struct crypto_state *cs,
+					   u64 gossip_index,
 					   const struct channel_id *channel_id,
 					   const char *desc,
-					   const u8 *errmsg),
+					   const u8 *err_for_them),
 			     va_list *ap)
 {
 	struct subd *sd = tal(ld, struct subd);
@@ -690,10 +698,12 @@ struct subd *new_channel_subd_(struct lightningd *ld,
 			       unsigned int (*msgcb)(struct subd *, const u8 *,
 						     const int *fds),
 			       void (*errcb)(void *channel,
-					     enum side sender,
+					     int peer_fd, int gossip_fd,
+					     const struct crypto_state *cs,
+					     u64 gossip_index,
 					     const struct channel_id *channel_id,
 					     const char *desc,
-					     const u8 *errmsg),
+					     const u8 *err_for_them),
 			       ...)
 {
 	va_list ap;

lightningd/subd.h

@@ -8,6 +8,7 @@
 #include <ccan/typesafe_cb/typesafe_cb.h>
 #include <common/msg_queue.h>
 
+struct crypto_state;
 struct io_conn;
 
 /* By convention, replies are requests + 100 */
@@ -36,12 +37,16 @@ struct subd {
 	unsigned (*msgcb)(struct subd *, const u8 *, const int *);
 	const char *(*msgname)(int msgtype);
 
-	/* Callback when an errormsg sent/received, or subd died. */
+	/* If peer_fd == -1, it was a disconnect/crash.  Otherwise,
+	 * sufficient information to hand back to gossipd, including the
+	 * error message we sent them if any. */
 	void (*errcb)(void *channel,
-		      enum side sender,
+		      int peer_fd, int gossip_fd,
+		      const struct crypto_state *cs,
+		      u64 gossip_index,
 		      const struct channel_id *channel_id,
 		      const char *desc,
-		      const u8 *errmsg);
+		      const u8 *err_for_them);
 
 	/* Buffer for input. */
 	u8 *msg_in;
@@ -103,16 +108,20 @@ struct subd *new_channel_subd_(struct lightningd *ld,
 			       unsigned int (*msgcb)(struct subd *, const u8 *,
 						     const int *fds),
 			       void (*errcb)(void *channel,
-					     enum side sender,
+					     int peer_fd, int gossip_fd,
+					     const struct crypto_state *cs,
+					     u64 gossip_index,
 					     const struct channel_id *channel_id,
 					     const char *desc,
-					     const u8 *errmsg),
+					     const u8 *err_for_them),
 			       ...);
 
 #define new_channel_subd(ld, name, channel, log, msgname, msgcb, errcb, ...) \
 	new_channel_subd_((ld), (name), (channel), (log), (msgname), (msgcb), \
 			  typesafe_cb_postargs(void, void *, (errcb),	\
-					       (channel), enum side,	\
+					       (channel), int, int,	\
+					       const struct crypto_state *, \
+					       u64,			\
 					       const struct channel_id *, \
 					       const char *, const u8 *), \
 			  __VA_ARGS__)

wallet/test/run-wallet.c

@@ -334,10 +334,12 @@ struct subd *new_channel_subd_(struct lightningd *ld UNNEEDED,
 			       unsigned int (*msgcb)(struct subd * UNNEEDED, const u8 * UNNEEDED,
 						     const int *fds) UNNEEDED,
 			       void (*errcb)(void *channel UNNEEDED,
-					     enum side sender UNNEEDED,
+					     int peer_fd UNNEEDED, int gossip_fd UNNEEDED,
+					     const struct crypto_state *cs UNNEEDED,
+					     u64 gossip_index UNNEEDED,
 					     const struct channel_id *channel_id UNNEEDED,
 					     const char *desc UNNEEDED,
-					     const u8 *errmsg) UNNEEDED,
+					     const u8 *err_for_them) UNNEEDED,
 			       ...)
 { fprintf(stderr, "new_channel_subd_ called!\n"); abort(); }
 /* Generated stub for new_json_result */