Implement (experimental!) fetch of bolt11 invoices from (simple) offers

.msggen.json

@@ -1979,6 +1979,7 @@
         "FetchinvoiceRequest": {
             "FetchInvoice.amount_msat": 2,
             "FetchInvoice.bip353": 10,
+            "FetchInvoice.bolt11": 11,
             "FetchInvoice.offer": 1,
             "FetchInvoice.payer_metadata": 9,
             "FetchInvoice.payer_note": 8,
@@ -8108,6 +8109,10 @@
             "added": "v25.02",
             "deprecated": null
         },
+        "FetchInvoice.bolt11": {
+            "added": "v26.09",
+            "deprecated": null
+        },
         "FetchInvoice.changes": {
             "added": "pre-v0.10.1",
             "deprecated": null
@@ -15904,6 +15909,10 @@
             "added": "pre-v0.10.1",
             "deprecated": null
         },
+        "onion_message_recv.onion_message.bolt11_invoice": {
+            "added": "v26.09",
+            "deprecated": null
+        },
         "onion_message_recv.onion_message.invoice": {
             "added": "pre-v0.10.1",
             "deprecated": null
@@ -15972,6 +15981,10 @@
             "added": "pre-v0.10.1",
             "deprecated": null
         },
+        "onion_message_recv_secret.onion_message.bolt11_invoice": {
+            "added": "v26.09",
+            "deprecated": null
+        },
         "onion_message_recv_secret.onion_message.invoice": {
             "added": "pre-v0.10.1",
             "deprecated": null

cln-rpc/src/hooks.rs

@@ -353,6 +353,8 @@ pub mod events{
 
     #[derive(Clone, Debug, Deserialize, Serialize)]
     pub struct OnionMessageRecvOnionMessage {
+        #[serde(skip_serializing_if = "Option::is_none")]
+        pub bolt11_invoice: Option<String>,
         #[serde(skip_serializing_if = "Option::is_none")]
         pub invoice: Option<String>,
         #[serde(skip_serializing_if = "Option::is_none")]
@@ -398,6 +400,8 @@ pub mod events{
 
     #[derive(Clone, Debug, Deserialize, Serialize)]
     pub struct OnionMessageRecvSecretOnionMessage {
+        #[serde(skip_serializing_if = "Option::is_none")]
+        pub bolt11_invoice: Option<String>,
         #[serde(skip_serializing_if = "Option::is_none")]
         pub invoice: Option<String>,
         #[serde(skip_serializing_if = "Option::is_none")]

common/features.c

@@ -144,6 +144,8 @@ static const struct feature_style feature_styles[] = {
 	  .copy_style = { [INIT_FEATURE] = FEATURE_REPRESENT,
 			  [NODE_ANNOUNCE_FEATURE] = FEATURE_REPRESENT,
 			  [CHANNEL_FEATURE] = FEATURE_DONT_REPRESENT} },
+	{ OPT_BOLT11_REQUEST,
+	  .copy_style = { [BOLT12_OFFER_FEATURE] = FEATURE_REPRESENT } },
 };
 
 struct dependency {

common/features.h

@@ -157,4 +157,9 @@ struct feature_set *feature_set_dup(const tal_t *ctx,
 
 #define OPT_SHUTDOWN_WRONG_FUNDING		104
 
+/* BOLT-fetch-bolt11 #9:
+ * | 2/3 | `option_bolt11_request` | Invoice request for a bolt11 invoice | 2 | | [BOLT #12][bolt12-bolt11-req] |
+ */
+#define OPT_BOLT11_REQUEST			2
+
 #endif /* LIGHTNING_COMMON_FEATURES_H */

contrib/msggen/msggen/schema.json

@@ -13907,6 +13907,13 @@
             ],
             "added": "v25.02"
           },
+          "bolt11": {
+            "type": "boolean",
+            "description": [
+              "Indicates we should fetch a bolt11 invoice instead (EXPERIMENTAL)"
+            ],
+            "added": "v26.09"
+          },
           "dev_reply_path": {
             "hidden": true
           },
@@ -13925,7 +13932,7 @@
           "invoice": {
             "type": "string",
             "description": [
-              "The BOLT12 invoice we fetched."
+              "The BOLT12 invoice we fetched (or BOLT11 if `bolt11` parameter was set)."
             ]
           },
           "changes": {
@@ -41747,6 +41754,13 @@
                   "BOLT #12 `invoice` payload."
                 ]
               },
+              "bolt11_invoice": {
+                "type": "string",
+                "added": "v26.09",
+                "description": [
+                  "BOLT #11 invoice payload."
+                ]
+              },
               "invoice_error": {
                 "type": "hex",
                 "description": [
@@ -41932,6 +41946,13 @@
                   "BOLT #12 `invoice` payload."
                 ]
               },
+              "bolt11_invoice": {
+                "type": "string",
+                "added": "v26.09",
+                "description": [
+                  "BOLT #11 invoice payload."
+                ]
+              },
               "invoice_error": {
                 "type": "hex",
                 "description": [

contrib/pyln-client/pyln/client/lightning.py

@@ -752,7 +752,7 @@ def feerates(self, style, urgent=None, normal=None, slow=None):
 
     def fetchinvoice(self, offer, amount_msat=None, quantity=None, recurrence_counter=None,
                      recurrence_start=None, recurrence_label=None, timeout=None, payer_note=None,
-                     payer_metadata=None, bip353=None):
+                     payer_metadata=None, bip353=None, bolt11=None):
         """
         Fetch an invoice for an offer.
         """
@@ -767,6 +767,7 @@ def fetchinvoice(self, offer, amount_msat=None, quantity=None, recurrence_counte
             "payer_note": payer_note,
             "payer_metadata": payer_metadata,
             "bip353": bip353,
+            "bolt11": bolt11,
         }
         return self.call("fetchinvoice", payload)
 

doc/schemas/fetchinvoice.json

@@ -76,6 +76,13 @@
         ],
         "added": "v25.02"
       },
+      "bolt11": {
+        "type": "boolean",
+        "description": [
+          "Indicates we should fetch a bolt11 invoice instead (EXPERIMENTAL)"
+        ],
+        "added": "v26.09"
+      },
       "dev_reply_path": {
         "hidden": true
       },
@@ -94,7 +101,7 @@
       "invoice": {
         "type": "string",
         "description": [
-          "The BOLT12 invoice we fetched."
+          "The BOLT12 invoice we fetched (or BOLT11 if `bolt11` parameter was set)."
         ]
       },
       "changes": {

doc/schemas/hook/onion_message_recv.json

@@ -113,6 +113,13 @@
               "BOLT #12 `invoice` payload."
             ]
           },
+          "bolt11_invoice": {
+            "type": "string",
+            "added": "v26.09",
+            "description": [
+              "BOLT #11 invoice payload."
+            ]
+          },
           "invoice_error": {
             "type": "hex",
             "description": [

doc/schemas/hook/onion_message_recv_secret.json

@@ -127,6 +127,13 @@
               "BOLT #12 `invoice` payload."
             ]
           },
+          "bolt11_invoice": {
+            "type": "string",
+            "added": "v26.09",
+            "description": [
+              "BOLT #11 invoice payload."
+            ]
+          },
           "invoice_error": {
             "type": "hex",
             "description": [

lightningd/invoice.c

@@ -1125,7 +1125,6 @@ static struct command_result *json_invoice(struct command *cmd,
 	struct jsonrpc_request *req;
 	struct plugin *plugin;
 	bool *hashonly;
-	const size_t inv_max_label_len = 128;
 	const jsmntok_t *dev_routes;
 
 	info = tal(cmd, struct invoice_info);
@@ -1151,11 +1150,6 @@ static struct command_result *json_invoice(struct command *cmd,
 		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
 				    "dev-routes requires --developer");
 
-	if (strlen(info->label->s) > inv_max_label_len) {
-		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
-				    "Label '%s' over %zu bytes", info->label->s, inv_max_label_len);
-	}
-
 	if (strlen(desc_val) > BOLT11_FIELD_BYTE_LIMIT && !*hashonly) {
 		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
 				    "Description greater than %d bytes "

lightningd/onion_message.c

@@ -59,6 +59,11 @@ static void onion_message_serialize(struct onion_message_hook_payload *payload,
 	if (payload->om->invoice)
 		json_add_hex_talarr(stream, "invoice", payload->om->invoice);
 
+	if (payload->om->bolt11_invoice)
+		json_add_stringn(stream, "bolt11_invoice",
+				 payload->om->bolt11_invoice,
+				 tal_bytelen(payload->om->bolt11_invoice));
+
 	if (payload->om->invoice_error)
 		json_add_hex_talarr(stream, "invoice_error",
 				    payload->om->invoice_error);

plugins/fetchinvoice.c

@@ -171,20 +171,45 @@ static struct command_result *handle_invreq_response(struct command *cmd,
 	u64 *expected_amount;
 	const struct recurrence *recurrence;
 
-	invtok = json_get_member(buf, om, "invoice");
+	/* Handle bolt11 case separately */
+	const char *invfield = sent->invreq->invreq_bolt11 ? "bolt11_invoice" : "invoice";
+	invtok = json_get_member(buf, om, invfield);
 	if (!invtok) {
 		plugin_log(cmd->plugin, LOG_UNUSUAL,
-			   "Neither invoice nor invoice_request_failed in reply %.*s",
+			   "Neither %s nor invoice_request_failed in reply %.*s",
+			   invfield,
 			   json_tok_full_len(om),
 			   json_tok_full(buf, om));
 		discard_result(command_fail(sent->cmd,
 					    OFFER_BAD_INVREQ_REPLY,
-					    "Neither invoice nor invoice_request_failed in reply %.*s",
+					    "Neither %s nor invoice_request_failed in reply %.*s",
+					    invfield,
 					    json_tok_full_len(om),
 					    json_tok_full(buf, om)));
 		return command_hook_success(cmd);
 	}
 
+	if (sent->invreq->invreq_bolt11) {
+		const char *bolt11, *err;
+
+		/* Sanity check that they sent us a valid reply */
+		bolt11 = json_strdup(tmpctx, buf, invtok);
+		if (!bolt11_decode(tmpctx, bolt11,
+				   plugin_feature_set(cmd->plugin),
+				   NULL,
+				   chainparams,
+				   &err)) {
+			badfield = tal_fmt(tmpctx, "invoice: %s", err);
+			goto badinv;
+		}
+		out = jsonrpc_stream_success(sent->cmd);
+		json_add_string(out, "invoice", bolt11);
+		json_object_start(out, "changes");
+		json_object_end(out);
+		discard_result(command_finished(sent->cmd, out));
+		return command_hook_success(cmd);
+	}
+
 	invbin = json_tok_bin_from_hex(cmd, buf, invtok);
 	cursor = invbin;
 	len = tal_bytelen(invbin);
@@ -929,6 +954,7 @@ struct command_result *json_fetchinvoice(struct command *cmd,
 	u32 *timeout;
 	u64 *quantity;
 	u32 *recurrence_counter, *recurrence_start;
+	bool *bolt11;
 
 	if (!param_check(cmd, buffer, params,
 			 p_req("offer", param_offer, &sent->offer),
@@ -941,6 +967,7 @@ struct command_result *json_fetchinvoice(struct command *cmd,
 			 p_opt("payer_note", param_string, &payer_note),
 			 p_opt("payer_metadata", param_bin_from_hex, &payer_metadata),
 			 p_opt("bip353", param_bip353, &bip353),
+			 p_opt_def("bolt11", param_bool, &bolt11, false),
 			 p_opt("dev_path_use_scidd", param_dev_scidd, &sent->dev_path_use_scidd),
 			 p_opt("dev_reply_path", param_dev_reply_path, &sent->dev_reply_path),
 		   NULL))
@@ -1148,6 +1175,13 @@ struct command_result *json_fetchinvoice(struct command *cmd,
 							strlen(payer_note),
 							0);
 
+	if (*bolt11) {
+		if (!feature_offered(invreq->offer_features, OPT_BOLT11_REQUEST))
+			return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+					    "Cannot request bolt11: offer does not implement it");
+		invreq->invreq_bolt11 = tal(invreq, struct tlv_invoice_request_invreq_bolt11);
+	}
+
 	/* If only checking, we're done now */
 	if (command_check_only(cmd))
 		return command_check_done(cmd);