connectd: add own err codes instead of generic -1

Make it possible for connectd to send an error code to lightningd in
addition to the error message. Introduce two new error codes, replacing
the catch-all -1.

This change, together with
ElementsProject#3395
will implement ElementsProject#3366

Changelog-Changed: The `connect` command now returns its own error codes instead of a generic -1.

common/jsonrpc_errors.h

@@ -42,6 +42,10 @@
 #define FUNDING_BROADCAST_FAIL          303
 #define FUNDING_STILL_SYNCING_BITCOIN   304
 
+/* `connect` errors */
+#define CONNECT_NO_KNOWN_ADDRESS	400
+#define CONNECT_ALL_ADDRESSES_FAILED	401
+
 /* Errors from `invoice` command */
 #define INVOICE_LABEL_ALREADY_EXISTS	900
 #define INVOICE_PREIMAGE_ALREADY_EXISTS	901

connectd/connect_wire.csv

@@ -44,6 +44,7 @@ msgdata,connectctl_connect_to_peer,addrhint,?wireaddr_internal,
 # Connectd->master: connect failed.
 msgtype,connectctl_connect_failed,2020
 msgdata,connectctl_connect_failed,id,node_id,
+msgdata,connectctl_connect_failed,failcode,u32,
 msgdata,connectctl_connect_failed,failreason,wirestring,
 msgdata,connectctl_connect_failed,seconds_to_delay,u32,
 msgdata,connectctl_connect_failed,addrhint,?wireaddr_internal,

connectd/connectd.c

@@ -30,6 +30,7 @@
 #include <common/daemon_conn.h>
 #include <common/decode_array.h>
 #include <common/features.h>
+#include <common/jsonrpc_errors.h>
 #include <common/memleak.h>
 #include <common/ping.h>
 #include <common/pseudorand.h>
@@ -565,22 +566,24 @@ static void connect_failed(struct daemon *daemon,
 			   const struct node_id *id,
 			   u32 seconds_waited,
 			   const struct wireaddr_internal *addrhint,
+			   u32 errcode,
 			   const char *errfmt, ...)
-	PRINTF_FMT(5,6);
+	PRINTF_FMT(6,7);
 
 static void connect_failed(struct daemon *daemon,
 			   const struct node_id *id,
 			   u32 seconds_waited,
 			   const struct wireaddr_internal *addrhint,
+			   u32 errcode,
 			   const char *errfmt, ...)
 {
 	u8 *msg;
 	va_list ap;
-	char *err;
+	char *errmsg;
 	u32 wait_seconds;
 
 	va_start(ap, errfmt);
-	err = tal_vfmt(tmpctx, errfmt, ap);
+	errmsg = tal_vfmt(tmpctx, errfmt, ap);
 	va_end(ap);
 
 	/* Wait twice as long to reconnect, between min and max. */
@@ -594,11 +597,11 @@ static void connect_failed(struct daemon *daemon,
 	 * happened.  We leave it to lightningd to decide if it wants to try
 	 * again, with the wait_seconds as a hint of how long before
 	 * asking. */
-	msg = towire_connectctl_connect_failed(NULL, id, err, wait_seconds,
-					       addrhint);
+	msg = towire_connectctl_connect_failed(NULL, id, errcode, errmsg,
+					       wait_seconds, addrhint);
 	daemon_conn_send(daemon->master, take(msg));
 
-	status_peer_debug(id, "Failed connected out: %s", err);
+	status_peer_debug(id, "Failed connected out: %s", errmsg);
 }
 
 /*~ This is the destructor for the (unsuccessful) connection.  We accumulate
@@ -717,7 +720,8 @@ static void try_connect_one_addr(struct connecting *connect)
 	if (connect->addrnum == tal_count(connect->addrs)) {
 		connect_failed(connect->daemon, &connect->id,
 			       connect->seconds_waited,
-			       connect->addrhint, "%s", connect->errors);
+			       connect->addrhint, CONNECT_ALL_ADDRESSES_FAILED,
+			       "%s", connect->errors);
 		tal_free(connect);
 		return;
 	}
@@ -1428,6 +1432,7 @@ static void try_connect_peer(struct daemon *daemon,
 	* to retry; an address may get gossiped or appear on the DNS seed. */
 	if (tal_count(addrs) == 0) {
 		connect_failed(daemon, id, seconds_waited, addrhint,
+			       CONNECT_NO_KNOWN_ADDRESS,
 			       "Unable to connect, no address known for peer");
 		return;
 	}

doc/lightning-connect.7.md

@@ -37,10 +37,21 @@ RETURN VALUE
 
 On success the peer *id* is returned.
 
-The following error codes may occur:
--   -1: Catchall nonspecific error. This may occur if the host is not
-    valid or there are problems communicating with the peer. **connect**
-    will make up to 10 attempts to connect to the peer before giving up.
+ERRORS
+------
+
+On failure, one of the following errors will be returned:
+
+    { "code" : 400, "message" : "Unable to connect, no address known for peer" }
+
+If some addresses are known but connecting to all of them failed, the message
+will contain details about the failures:
+
+    { "code" : 401, "message" : "..." }
+
+If the given parameters are wrong:
+
+    { "code" : -32602, "message" : "..." }
 
 AUTHOR
 ------

lightningd/connect_control.c

@@ -16,6 +16,7 @@
 #include <errno.h>
 #include <hsmd/capabilities.h>
 #include <hsmd/gen_hsm_wire.h>
+#include <inttypes.h>
 #include <lightningd/channel.h>
 #include <lightningd/connect_control.h>
 #include <lightningd/hsm_control.h>
@@ -231,21 +232,23 @@ void delay_then_reconnect(struct channel *channel, u32 seconds_delay,
 static void connect_failed(struct lightningd *ld, const u8 *msg)
 {
 	struct node_id id;
-	char *err;
+	u32 errcode;
+	char *errmsg;
 	struct connect *c;
 	u32 seconds_to_delay;
 	struct wireaddr_internal *addrhint;
 	struct channel *channel;
 
-	if (!fromwire_connectctl_connect_failed(tmpctx, msg, &id, &err,
-						&seconds_to_delay, &addrhint))
+	if (!fromwire_connectctl_connect_failed(tmpctx, msg, &id, &errcode, &errmsg,
+						&seconds_to_delay, &addrhint) ||
+	    errcode > INT_MAX)
 		fatal("Connect gave bad CONNECTCTL_CONNECT_FAILED message %s",
 		      tal_hex(msg, msg));
 
 	/* We can have multiple connect commands: fail them all */
 	while ((c = find_connect(ld, &id)) != NULL) {
 		/* They delete themselves from list */
-		was_pending(command_fail(c->cmd, LIGHTNINGD, "%s", err));
+		was_pending(command_fail(c->cmd, (int)errcode, "%s", errmsg));
 	}
 
 	/* If we have an active channel, then reconnect. */