plugins/pay: send payment_metadata if provided in invoice.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: Protocol: `pay` (and decode, etc) supports bolt11 payment_metadata a-la lightning/bolts#912

plugins/keysend.c

@@ -186,6 +186,7 @@ static struct command_result *json_keysend(struct command *cmd, const char *buf,
 	p->destination = tal_steal(p, destination);
 	p->destination_has_tlv = true;
 	p->payment_secret = NULL;
+	p->payment_metadata = NULL;
 	p->amount = *msat;
 	p->routes = tal_steal(p, hints);
 	// 22 is the Rust-Lightning default and the highest minimum we know of.

plugins/libplugin-pay.c

@@ -1596,7 +1596,7 @@ static struct command_result *payment_createonion_success(struct command *cmd,
 /* Temporary serialization method for the tlv_payload.data until we rework the
  * API that is generated from the specs to use the setter/getter interface. */
 static void tlvstream_set_tlv_payload_data(struct tlv_field **stream,
-					   struct secret *payment_secret,
+					   const struct secret *payment_secret,
 					   u64 total_msat)
 {
 	u8 *ser = tal_arr(NULL, u8, 0);
@@ -1612,7 +1612,8 @@ static void payment_add_hop_onion_payload(struct payment *p,
 					  struct route_hop *next,
 					  bool final,
 					  bool force_tlv,
-					  struct secret *payment_secret)
+					  const struct secret *payment_secret,
+					  const u8 *payment_metadata)
 {
 	struct createonion_request *cr = p->createonion_request;
 	u32 cltv = p->start_block + next->delay + 1;
@@ -1660,6 +1661,11 @@ static void payment_add_hop_onion_payload(struct payment *p,
 			    fields, payment_secret,
 			    root->amount.millisatoshis); /* Raw: TLV payload generation*/
 		}
+		if (payment_metadata != NULL) {
+			assert(final);
+			tlvstream_set_raw(fields, TLV_TLV_PAYLOAD_PAYMENT_METADATA,
+					  payment_metadata, tal_bytelen(payment_metadata));
+		}
 		break;
 	}
 }
@@ -1700,7 +1706,7 @@ static void payment_compute_onion_payloads(struct payment *p)
 		 * i+1 */
 		payment_add_hop_onion_payload(p, &cr->hops[i], &p->route[i],
 					      &p->route[i + 1], false, false,
-					      NULL);
+					      NULL, NULL);
 		tal_append_fmt(&routetxt, "%s -> ",
 			       type_to_string(tmpctx, struct short_channel_id,
 					      &p->route[i].scid));
@@ -1710,7 +1716,7 @@ static void payment_compute_onion_payloads(struct payment *p)
 	payment_add_hop_onion_payload(
 	    p, &cr->hops[hopcount - 1], &p->route[hopcount - 1],
 	    &p->route[hopcount - 1], true, root->destination_has_tlv,
-	    root->payment_secret);
+	    root->payment_secret, root->payment_metadata);
 	tal_append_fmt(&routetxt, "%s",
 		       type_to_string(tmpctx, struct short_channel_id,
 				      &p->route[hopcount - 1].scid));

plugins/libplugin-pay.h

@@ -185,6 +185,9 @@ struct payment {
 	/* Payment secret, from the invoice if any. */
 	struct secret *payment_secret;
 
+	/* Payment metadata, from the invoice if any. */
+	u8 *payment_metadata;
+
 	u64 groupid;
 	u32 partid;
 	u32 next_partid;

plugins/pay.c

@@ -108,6 +108,9 @@ struct pay_command {
 	/* Payment secret, if specified by invoice. */
 	const char *payment_secret;
 
+	/* Payment metadata, if specified by invoice. */
+	const char *payment_metadata;
+
 	/* Description, if any. */
 	const char *label;
 
@@ -849,6 +852,8 @@ static struct command_result *getroute_done(struct command *cmd,
 		json_add_string(req->js, "label", pc->label);
 	if (pc->payment_secret)
 		json_add_string(req->js, "payment_secret", pc->payment_secret);
+	if (pc->payment_metadata)
+		json_add_string(req->js, "payment_metadata", pc->payment_metadata);
 
 	return send_outreq(cmd->plugin, req);
 }
@@ -1368,6 +1373,11 @@ static struct command_result *json_pay(struct command *cmd,
 						sizeof(*b11->payment_secret));
 	else
 		pc->payment_secret = NULL;
+	if (b11->metadata)
+		pc->payment_metadata = tal_hex(pc, b11->metadata);
+	else
+		pc->payment_metadata = NULL;
+
 	/* We try first without using routehint */
 	pc->current_routehint = NULL;
 	pc->routehints = filter_routehints(pc, b11->routes);
@@ -2376,6 +2386,10 @@ static struct command_result *json_paymod(struct command *cmd,
 		p->payment_hash = tal_dup(p, struct sha256, &b11->payment_hash);
 		p->payment_secret =
 			tal_dup_or_null(p, struct secret, b11->payment_secret);
+		if (b11->metadata)
+			p->payment_metadata = tal_dup_talarr(p, u8, b11->metadata);
+		else
+			p->payment_metadata = NULL;
 		/* FIXME: libplugin-pay plays with this array, and there are many FIXMEs
 		 * about it.  But it looks like a leak, so we suppress it here. */
 		p->routes = notleak_with_children(tal_steal(p, b11->routes));

tests/test_pay.py

@@ -5043,6 +5043,21 @@ def test_pay_manual_exclude(node_factory, bitcoind):
 
 
 def test_pay_bolt11_metadata(node_factory, bitcoind):
-    l1 = node_factory.get_node()
-
-    b11 = l1.rpc.decode('lnbcrt10m1pvjluezpp5qqqsyqcyq5rqwzqfqqqsyqcyq5rqwzqfqqqsyqcyq5rqwzqfqypqdp9wpshjmt9de6zqmt9w3skgct5vysxjmnnd9jx2mq8q8a04uqcqpjsp5zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zygs9q2gqqqqqqsgqrk6hdutpaetmm3afjn0vfczgeyv0cy739rr939kwd4h5j3khxcskhgf59eaqy8wyq82tsnaqc5y32ed4jg34jw7rmeva9u6kfhymawgptmy5f6')
+    l1, l2 = node_factory.line_graph(2)
+
+    # BOLT #11:
+    # > ### Please send 0.01 BTC with payment metadata 0x01fafaf0
+    # > lnbc10m1pvjluezpp5qqqsyqcyq5rqwzqfqqqsyqcyq5rqwzqfqqqsyqcyq5rqwzqfqypqdp9wpshjmt9de6zqmt9w3skgct5vysxjmnnd9jx2mq8q8a04uqsp5zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zygs9q2gqqqqqqsgq7hf8he7ecf7n4ffphs6awl9t6676rrclv9ckg3d3ncn7fct63p6s365duk5wrk202cfy3aj5xnnp5gs3vrdvruverwwq7yzhkf5a3xqpd05wjc
+
+    b11 = l1.rpc.decode('lnbc10m1pvjluezpp5qqqsyqcyq5rqwzqfqqqsyqcyq5rqwzqfqqqsyqcyq5rqwzqfqypqdp9wpshjmt9de6zqmt9w3skgct5vysxjmnnd9jx2mq8q8a04uqsp5zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zyg3zygs9q2gqqqqqqsgq7hf8he7ecf7n4ffphs6awl9t6676rrclv9ckg3d3ncn7fct63p6s365duk5wrk202cfy3aj5xnnp5gs3vrdvruverwwq7yzhkf5a3xqpd05wjc')
+    assert b11['payment_metadata'] == '01fafaf0'
+
+    # I previously hacked lightningd to add "this is metadata" to metadata.
+    inv = "lnbcrt1230n1p3z4n67pp5ve584t0cv27hwmy0cx9ca8uwyqyfw9y9dm3r8vus9fv36r2l9yjsdq8v3jhxccxqyjw5qmq6w35xjueqd9ejqmt9w3skgct5vycqp9sp5q8g040f9rl9mu2unkjuj0vn262s6nyrhz5hythk3ueu2lfzahmzs9q2sqqqqqyssqadkaju3n7we0f5d3yudur5jneff8d3z7hspnewa6e47g3uktzdt43stlkk9h9k9lma7rmpsjvmgqastdwyhd5ctln76l0nf0kymzvvsquqc580"
+    # Make l2 "know" about this invoice.
+    l2.rpc.invoice(msatoshi='123000', label='label1', description='desc', preimage='00' * 32)
+
+    with pytest.raises(RpcError, match=r'WIRE_INVALID_ONION_PAYLOAD'):
+        l1.rpc.pay(inv)
+
+    l2.daemon.wait_for_log("Unexpected payment_metadata {}".format(b'this is metadata'.hex()))