lightningd: control onion messages by `experimental-onion-messages` option.

Note that this also changes so the feature is not represented in channels,
reflecting the recent drafts.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: `experimental-onion-messages` enables send, receive and relay of onion messages.

common/features.c

@@ -68,17 +68,16 @@ static const struct feature_style feature_styles[] = {
 	  .copy_style = { [INIT_FEATURE] = FEATURE_REPRESENT,
 			  [NODE_ANNOUNCE_FEATURE] = FEATURE_REPRESENT,
 			  [CHANNEL_FEATURE] = FEATURE_DONT_REPRESENT } },
+	{ OPT_ONION_MESSAGES,
+	  .copy_style = { [INIT_FEATURE] = FEATURE_REPRESENT,
+			  [NODE_ANNOUNCE_FEATURE] = FEATURE_REPRESENT,
+			  [BOLT11_FEATURE] = FEATURE_REPRESENT,
+			  [CHANNEL_FEATURE] = FEATURE_DONT_REPRESENT} },
 #if EXPERIMENTAL_FEATURES
 	{ OPT_ANCHOR_OUTPUTS,
 	  .copy_style = { [INIT_FEATURE] = FEATURE_REPRESENT,
 			  [NODE_ANNOUNCE_FEATURE] = FEATURE_REPRESENT,
 			  [CHANNEL_FEATURE] = FEATURE_DONT_REPRESENT } },
-	{ OPT_ONION_MESSAGES,
-	  .copy_style = { [INIT_FEATURE] = FEATURE_REPRESENT,
-			  [NODE_ANNOUNCE_FEATURE] = FEATURE_REPRESENT,
-			  [BOLT11_FEATURE] = FEATURE_REPRESENT,
-			  [CHANNEL_FEATURE] = FEATURE_REPRESENT_AS_OPTIONAL} },
-
 	{ OPT_DUAL_FUND,
 	  .copy_style = { [INIT_FEATURE] = FEATURE_REPRESENT,
 			  [NODE_ANNOUNCE_FEATURE] = FEATURE_REPRESENT,

common/features.h

@@ -122,7 +122,5 @@ u8 *featurebits_or(const tal_t *ctx, const u8 *f1 TAKES, const u8 *f2 TAKES);
  *
  * | 102/103 | `option_onion_messages` |... INC+ ...
  */
-#if EXPERIMENTAL_FEATURES
 #define OPT_ONION_MESSAGES			102
-#endif
 #endif /* LIGHTNING_COMMON_FEATURES_H */

gossipd/gossipd.c

@@ -435,7 +435,6 @@ static bool handle_local_channel_announcement(struct daemon *daemon,
 	return true;
 }
 
-#if EXPERIMENTAL_FEATURES
 /* Peer sends onion msg. */
 static u8 *handle_onion_message(struct peer *peer, const u8 *msg)
 {
@@ -450,6 +449,11 @@ static u8 *handle_onion_message(struct peer *peer, const u8 *msg)
 	struct tlv_onionmsg_payload *om;
 	struct tlv_onion_message_tlvs *tlvs = tlv_onion_message_tlvs_new(msg);
 
+	/* Ignore unless explicitly turned on. */
+	if (!feature_offered(peer->daemon->our_features->bits[NODE_ANNOUNCE_FEATURE],
+			     OPT_ONION_MESSAGES))
+		return NULL;
+
 	/* FIXME: ratelimit! */
 	if (!fromwire_onion_message(msg, msg, &onion, tlvs))
 		return towire_errorfmt(peer, NULL, "Bad onion_message");
@@ -690,7 +694,6 @@ static struct io_plan *onionmsg_req(struct io_conn *conn, struct daemon *daemon,
 	}
 	return daemon_conn_read_next(conn, daemon->master);
 }
-#endif /* EXPERIMENTAL_FEATURES */
 
 /*~ This is where the per-peer daemons send us messages.  It's either forwarded
  * gossip, or a request for information.  We deliberately use non-overlapping
@@ -731,11 +734,9 @@ static struct io_plan *peer_msg_in(struct io_conn *conn,
 	case WIRE_PONG:
 		err = handle_pong(peer, msg);
 		goto handled_relay;
-#if EXPERIMENTAL_FEATURES
 	case WIRE_ONION_MESSAGE:
 		err = handle_onion_message(peer, msg);
 		goto handled_relay;
-#endif
 
 	/* These are non-gossip messages (!is_msg_for_gossipd()) */
 	case WIRE_INIT:
@@ -757,9 +758,6 @@ static struct io_plan *peer_msg_in(struct io_conn *conn,
 	case WIRE_CHANNEL_REESTABLISH:
 	case WIRE_ANNOUNCEMENT_SIGNATURES:
 	case WIRE_GOSSIP_TIMESTAMP_FILTER:
-#if !EXPERIMENTAL_FEATURES
-	case WIRE_ONION_MESSAGE:
-#endif
 #if EXPERIMENTAL_FEATURES
 	case WIRE_TX_ADD_INPUT:
 	case WIRE_TX_REMOVE_INPUT:
@@ -1934,9 +1932,7 @@ static struct io_plan *recv_req(struct io_conn *conn,
 #endif /* !DEVELOPER */
 
 	case WIRE_GOSSIPD_SEND_ONIONMSG:
-#if EXPERIMENTAL_FEATURES
 		return onionmsg_req(conn, daemon, msg);
-#endif
 	/* We send these, we don't receive them */
 	case WIRE_GOSSIPD_GETNODES_REPLY:
 	case WIRE_GOSSIPD_GETROUTE_REPLY:

lightningd/gossip_control.c

@@ -161,18 +161,12 @@ static unsigned gossip_msg(struct subd *gossip, const u8 *msg, const int *fds)
 	case WIRE_GOSSIPD_GET_STRIPPED_CUPDATE_REPLY:
 		break;
 
-#if EXPERIMENTAL_FEATURES
 	case WIRE_GOSSIPD_GOT_ONIONMSG_TO_US:
 		handle_onionmsg_to_us(gossip->ld, msg);
 		break;
 	case WIRE_GOSSIPD_GOT_ONIONMSG_FORWARD:
 		handle_onionmsg_forward(gossip->ld, msg);
 		break;
-#else
-	case WIRE_GOSSIPD_GOT_ONIONMSG_TO_US:
-	case WIRE_GOSSIPD_GOT_ONIONMSG_FORWARD:
-		break;
-#endif
 	case WIRE_GOSSIPD_PING_REPLY:
 		ping_reply(gossip, msg);
 		break;

lightningd/onion_message.c

@@ -6,7 +6,6 @@
 #include <lightningd/plugin_hook.h>
 #include <lightningd/subd.h>
 
-#if EXPERIMENTAL_FEATURES
 struct onion_message_hook_payload {
 	/* Optional */
 	struct pubkey *blinding_in;
@@ -406,6 +405,11 @@ static struct command_result *json_send_onion_message(struct command *cmd,
 		   NULL))
 		return command_param_failed();
 
+	if (!feature_offered(cmd->ld->our_features->bits[NODE_ANNOUNCE_FEATURE],
+			     OPT_ONION_MESSAGES))
+		return command_fail(cmd, LIGHTNINGD,
+				    "experimental-onion-messages not enabled");
+
 	node_id_from_pubkey(&first_id, &hops[0].id);
 
 	/* Sanity check first; gossipd doesn't bother telling us if peer
@@ -461,4 +465,3 @@ static const struct json_command send_onion_message_command = {
 	"Send message over {hops} (id, [short_channel_id], [blinding], [enctlv], [invoice], [invoice_request], [invoice_error], [rawtlv]) with optional {reply_path} (blinding, path[id, enctlv])"
 };
 AUTODATA(json_command, &send_onion_message_command);
-#endif /* EXPERIMENTAL_FEATURES */

lightningd/options.c

@@ -799,6 +799,14 @@ static char *opt_set_dual_fund(struct lightningd *ld)
 	return NULL;
 }
 
+static char *opt_set_onion_messages(struct lightningd *ld)
+{
+	feature_set_or(ld->our_features,
+		       take(feature_set_for_feature(NULL,
+						    OPTIONAL_FEATURE(OPT_ONION_MESSAGES))));
+	return NULL;
+}
+
 static void register_opts(struct lightningd *ld)
 {
 	/* This happens before plugins started */
@@ -846,6 +854,11 @@ static void register_opts(struct lightningd *ld)
 				 " and allow peers to establish channels"
 				 " via v2 channel open protocol");
 
+	/* This affects our features, so set early. */
+	opt_register_early_noarg("--experimental-onion-messages",
+				 opt_set_onion_messages, ld,
+				 "EXPERIMENTAL: enable send, receive and relay"
+				 " of onion messages");
 
 	opt_register_noarg("--help|-h", opt_lightningd_usage, ld,
 				 "Print this message.");
@@ -1262,6 +1275,11 @@ static void add_config(struct lightningd *ld,
 				      feature_offered(ld->our_features
 						      ->bits[INIT_FEATURE],
 						      OPT_DUAL_FUND));
+		} else if (opt->cb == (void *)opt_set_onion_messages) {
+			json_add_bool(response, name0,
+				      feature_offered(ld->our_features
+						      ->bits[INIT_FEATURE],
+						      OPT_ONION_MESSAGES));
 		} else if (opt->cb == (void *)plugin_opt_flag_set) {
 			/* Noop, they will get added below along with the
 			 * OPT_HASARG options. */

tests/test_misc.py

@@ -2297,9 +2297,8 @@ def test_sendcustommsg(node_factory):
             serialized=serialized, peer_id=l2.info['id']))
 
 
-@unittest.skipIf(not EXPERIMENTAL_FEATURES, "Needs sendonionmessage")
 def test_sendonionmessage(node_factory):
-    l1, l2, l3 = node_factory.line_graph(3)
+    l1, l2, l3 = node_factory.line_graph(3, opts={'experimental-onion-messages': None})
 
     blindedpathtool = os.path.join(os.path.dirname(__file__), "..", "devtools", "blindedpath")
 

tests/utils.py

@@ -49,9 +49,6 @@ def expected_node_features(wumbo_channels=False, extra=[]):
 def expected_channel_features(wumbo_channels=False, extra=[]):
     """Return the expected channel features hexstring for this configuration"""
     features = []
-    if EXPERIMENTAL_FEATURES:
-        # OPT_ONION_MESSAGES
-        features += [103]
     return hex_bits(features + extra)