API: txprepare now support mutiple outputs

common/json_helpers.c

@@ -60,6 +60,16 @@ bool json_to_sat(const char *buffer, const jsmntok_t *tok,
 	return parse_amount_sat(sat, buffer + tok->start, tok->end - tok->start);
 }
 
+bool json_to_sat_or_all(const char *buffer, const jsmntok_t *tok,
+			struct amount_sat *sat)
+{
+	if (json_tok_streq(buffer, tok, "all")) {
+		*sat = AMOUNT_SAT(-1ULL);
+		return true;
+	}
+	return json_to_sat(buffer, tok, sat);
+}
+
 bool json_to_short_channel_id(const char *buffer, const jsmntok_t *tok,
 			      struct short_channel_id *scid,
 			      bool may_be_deprecated_form)

common/json_helpers.h

@@ -32,6 +32,11 @@ bool json_to_short_channel_id(const char *buffer, const jsmntok_t *tok,
 bool json_to_sat(const char *buffer, const jsmntok_t *tok,
 		 struct amount_sat *sat);
 
+/* Extract a satoshis amount from this */
+/* If the string is "all", set amonut as AMOUNT_SAT(-1ULL). */
+bool json_to_sat_or_all(const char *buffer, const jsmntok_t *tok,
+			struct amount_sat *sat);
+
 /* Extract a millisatoshis amount from this */
 bool json_to_msat(const char *buffer, const jsmntok_t *tok,
 		  struct amount_msat *msat);

common/json_tok.c

@@ -183,7 +183,19 @@ struct command_result *param_sat(struct command *cmd, const char *name,
 		return NULL;
 
 	return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
-			    "'%s' should be a satoshi amount, not '%.*s'",
+			    "%s should be a satoshi amount, not '%.*s'",
-			    name, tok->end - tok->start, buffer + tok->start);
+			    name ? name : "amount field",
+			    tok->end - tok->start, buffer + tok->start);
 }
 
+struct command_result *param_sat_or_all(struct command *cmd, const char *name,
+					const char *buffer, const jsmntok_t *tok,
+					struct amount_sat **sat)
+{
+	if (json_tok_streq(buffer, tok, "all")) {
+		*sat = tal(cmd, struct amount_sat);
+		**sat = AMOUNT_SAT(-1ULL);
+		return NULL;
+	}
+	return param_sat(cmd, name, buffer, tok, sat);
+}

common/json_tok.h

@@ -74,6 +74,12 @@ struct command_result *param_sat(struct command *cmd, const char *name,
 				 const char *buffer, const jsmntok_t *tok,
 				 struct amount_sat **sat);
 
+/* Extract satoshi amount from this string. */
+/* If the string is "all", set amonut as AMOUNT_SAT(-1ULL). */
+struct command_result *param_sat_or_all(struct command *cmd, const char *name,
+					const char *buffer, const jsmntok_t *tok,
+					struct amount_sat **sat);
+
 /*
  * Set the address of @out to @tok.  Used as a callback by handlers that
  * want to unmarshal @tok themselves.

contrib/pylightning/lightning/lightning.py

@@ -878,18 +878,18 @@ class LightningRpc(UnixDomainSocketRpc):
         }
         return self.call("withdraw", payload)
 
-    def txprepare(self, destination, satoshi, feerate=None, minconf=None):
+    def txprepare(self, outputs, feerate=None, minconf=None):
         """
-        Prepare a bitcoin transaction which sends to {destination} address
+        Prepare a bitcoin transaction which sends to [outputs].
-        {satoshi} (or "all") amount via Bitcoin transaction. Only select outputs
+        The format of output is like [{address1: amount1},
-        with {minconf} confirmations.
+        {address2: amount2}], or [{address: "all"}]).
+        Only select outputs with {minconf} confirmations.
 
         Outputs will be reserved until you call txdiscard or txsend, or
         lightningd restarts.
         """
         payload = {
-            "destination": destination,
+            "outputs": outputs,
-            "satoshi": satoshi,
             "feerate": feerate,
             "minconf": minconf,
         }

hsmd/hsm_wire.csv

@@ -69,8 +69,8 @@ msgtype,hsm_sign_withdrawal,7
 msgdata,hsm_sign_withdrawal,satoshi_out,amount_sat,
 msgdata,hsm_sign_withdrawal,change_out,amount_sat,
 msgdata,hsm_sign_withdrawal,change_keyindex,u32,
-msgdata,hsm_sign_withdrawal,scriptpubkey_len,u16,
+msgdata,hsm_sign_withdrawal,num_outputs,u16,
-msgdata,hsm_sign_withdrawal,scriptpubkey,u8,scriptpubkey_len
+msgdata,hsm_sign_withdrawal,outputs,bitcoin_tx_output,num_outputs
 msgdata,hsm_sign_withdrawal,num_inputs,u16,
 msgdata,hsm_sign_withdrawal,inputs,utxo,num_inputs
 

hsmd/hsmd.c

@@ -1514,24 +1514,17 @@ static struct io_plan *handle_sign_withdrawal_tx(struct io_conn *conn,
 	struct utxo **utxos;
 	struct bitcoin_tx *tx;
 	struct pubkey changekey;
-	u8 *scriptpubkey;
 	struct bitcoin_tx_output **outputs;
 
-	outputs = tal_arr(tmpctx, struct bitcoin_tx_output *, 0);
 	if (!fromwire_hsm_sign_withdrawal(tmpctx, msg_in, &satoshi_out,
 					  &change_out, &change_keyindex,
-					  &scriptpubkey, &utxos))
+					  &outputs, &utxos))
 		return bad_req(conn, c, msg_in);
 
 	if (!bip32_pubkey(&secretstuff.bip32, &changekey, change_keyindex))
 		return bad_req_fmt(conn, c, msg_in,
 				   "Failed to get key %u", change_keyindex);
 
-	struct bitcoin_tx_output *output = tal(outputs,
-					       struct bitcoin_tx_output);
-	output->script = tal_steal(output, scriptpubkey);
-	output->amount = satoshi_out;
-	tal_arr_expand(&outputs, output);
 	tx = withdraw_tx(tmpctx, c->chainparams,
 			 cast_const2(const struct utxo **, utxos), outputs,
 			 &changekey, change_out, NULL, NULL);

tests/test_wallet.py

@@ -207,8 +207,7 @@ def test_txprepare(node_factory, bitcoind):
     bitcoind.generate_block(1)
     wait_for(lambda: len(l1.rpc.listfunds()['outputs']) == 10)
 
-    prep = l1.rpc.txprepare('bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg',
+    prep = l1.rpc.txprepare([{'bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg': Millisatoshi(amount * 3 * 1000)}])
-                            Millisatoshi(amount * 3 * 1000))
     decode = bitcoind.rpc.decoderawtransaction(prep['unsigned_tx'])
     assert decode['txid'] == prep['txid']
     # 4 inputs, 2 outputs.
@@ -231,8 +230,7 @@ def test_txprepare(node_factory, bitcoind):
     assert decode['vout'][changenum]['scriptPubKey']['type'] == 'witness_v0_keyhash'
 
     # Now prepare one with no change.
-    prep2 = l1.rpc.txprepare('bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg',
+    prep2 = l1.rpc.txprepare([{'bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg': 'all'}])
-                             'all')
     decode = bitcoind.rpc.decoderawtransaction(prep2['unsigned_tx'])
     assert decode['txid'] == prep2['txid']
     # 6 inputs, 1 outputs.
@@ -250,8 +248,7 @@ def test_txprepare(node_factory, bitcoind):
     assert discard['txid'] == prep['txid']
     assert discard['unsigned_tx'] == prep['unsigned_tx']
 
-    prep3 = l1.rpc.txprepare('bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg',
+    prep3 = l1.rpc.txprepare([{'bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg': 'all'}])
-                             'all')
     decode = bitcoind.rpc.decoderawtransaction(prep3['unsigned_tx'])
     assert decode['txid'] == prep3['txid']
     # 4 inputs, 1 outputs.
@@ -271,8 +268,7 @@ def test_txprepare(node_factory, bitcoind):
     # Discard everything, we should now spend all inputs.
     l1.rpc.txdiscard(prep2['txid'])
     l1.rpc.txdiscard(prep3['txid'])
-    prep4 = l1.rpc.txprepare('bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg',
+    prep4 = l1.rpc.txprepare([{'bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg': 'all'}])
-                             'all')
     decode = bitcoind.rpc.decoderawtransaction(prep4['unsigned_tx'])
     assert decode['txid'] == prep4['txid']
     # 10 inputs, 1 outputs.
@@ -299,8 +295,7 @@ def test_txsend(node_factory, bitcoind):
     bitcoind.generate_block(1)
     wait_for(lambda: len(l1.rpc.listfunds()['outputs']) == 10)
 
-    prep = l1.rpc.txprepare('bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg',
+    prep = l1.rpc.txprepare([{'bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg': Millisatoshi(amount * 3 * 1000)}])
-                            Millisatoshi(amount * 3 * 1000))
     out = l1.rpc.txsend(prep['txid'])
 
     # Cannot discard after send!
@@ -343,8 +338,7 @@ def test_txprepare_restart(node_factory, bitcoind):
     bitcoind.generate_block(1)
     wait_for(lambda: [o['status'] for o in l1.rpc.listfunds()['outputs']] == ['confirmed'] * 10)
 
-    prep = l1.rpc.txprepare('bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg',
+    prep = l1.rpc.txprepare([{'bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg': 'all'}])
-                            'all')
     decode = bitcoind.rpc.decoderawtransaction(prep['unsigned_tx'])
     assert decode['txid'] == prep['txid']
     # All 10 inputs
@@ -359,8 +353,7 @@ def test_txprepare_restart(node_factory, bitcoind):
     with pytest.raises(RpcError, match=r'not an unreleased txid'):
         l1.rpc.txdiscard(prep['txid'])
 
-    prep = l1.rpc.txprepare('bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg',
+    prep = l1.rpc.txprepare([{'bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg': 'all'}])
-                            'all')
 
     decode = bitcoind.rpc.decoderawtransaction(prep['unsigned_tx'])
     assert decode['txid'] == prep['txid']
@@ -377,8 +370,7 @@ def test_txprepare_restart(node_factory, bitcoind):
     for i in decode['vin']:
         assert l1.daemon.is_in_log('wallet: reserved output {}/{} reset to available'.format(i['txid'], i['vout']))
 
-    prep = l1.rpc.txprepare('bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg',
+    prep = l1.rpc.txprepare([{'bcrt1qeyyk6sl5pr49ycpqyckvmttus5ttj25pd0zpvg': 'all'}])
-                            'all')
     decode = bitcoind.rpc.decoderawtransaction(prep['unsigned_tx'])
     assert decode['txid'] == prep['txid']
     # All 10 inputs

tools/generate-wire.py

@@ -216,6 +216,7 @@ class Type(FieldSet):
         'bitcoin_tx',
         'wirestring',
         'per_peer_state',
+        'bitcoin_tx_output',
     ]
 
     # Some BOLT types are re-typed based on their field name

wallet/wallet.h

@@ -58,8 +58,8 @@ struct unreleased_tx {
 	struct list_node list;
 	/* All the utxos. */
 	struct wallet_tx *wtx;
-	/* Scriptpubkey this pays to. */
+	/* Outputs(scriptpubkey and satoshi) this pays to. */
-	const u8 *destination;
+	struct bitcoin_tx_output **outputs;
 	/* The tx itself (unsigned initially) */
 	struct bitcoin_tx *tx;
 	struct bitcoin_txid txid;

wallet/walletrpc.c

@@ -93,7 +93,9 @@ static struct command_result *param_bitcoin_address(struct command *cmd,
 					      scriptpubkey)) {
 	case ADDRESS_PARSE_UNRECOGNIZED:
 		return command_fail(cmd, LIGHTNINGD,
-				    "Could not parse destination address");
+				    "Could not parse destination address, "
+				    "%s should be a valid address",
+				    name ? name : "address field");
 	case ADDRESS_PARSE_WRONG_NETWORK:
 		return command_fail(cmd, LIGHTNINGD,
 				    "Destination address is not on network %s",
@@ -117,7 +119,8 @@ static struct command_result *broadcast_and_wait(struct command *cmd,
 					     utx->wtx->amount,
 					     utx->wtx->change,
 					     utx->wtx->change_key_index,
-					     utx->destination,
+					     cast_const2(const struct bitcoin_tx_output **,
+							 utx->outputs),
 					     utx->wtx->utxos);
 
 	if (!wire_sync_write(cmd->ld->hsm_fd, take(msg)))
@@ -152,36 +155,65 @@ static struct command_result *broadcast_and_wait(struct command *cmd,
 
 /* Common code for withdraw and txprepare.
  *
- * Returns NULL on success, and fills in wtx, destination and
+ * Returns NULL on success, and fills in wtx, output and
  * maybe changekey (owned by cmd).  Otherwise, cmd has failed, so don't
  * access it! (It's been freed). */
 static struct command_result *json_prepare_tx(struct command *cmd,
 					      const char *buffer,
 					      const jsmntok_t *params,
-					      struct unreleased_tx **utx)
+					      struct unreleased_tx **utx,
+					      bool for_withdraw)
 {
 	u32 *feerate_per_kw;
 	struct command_result *res;
 	u32 *minconf, maxheight;
 	struct pubkey *changekey;
 	struct bitcoin_tx_output **outputs;
+	const jsmntok_t *outputstok, *t;
+	const u8 *destination = NULL;
+	size_t out_len, i;
 
 	*utx = tal(cmd, struct unreleased_tx);
 	(*utx)->wtx = tal(*utx, struct wallet_tx);
 	wtx_init(cmd, (*utx)->wtx, AMOUNT_SAT(-1ULL));
-	outputs = tal_arr(tmpctx, struct bitcoin_tx_output *, 0);
 
+	if (!for_withdraw) {
+		/* From v0.7.3, the new style for *txprepare* use array of outputs
+		 * to replace original 'destination' and 'satoshi' parameters.*/
+		if (!param(cmd, buffer, params,
+			   p_req("outputs", param_array, &outputstok),
+			   p_opt("feerate", param_feerate, &feerate_per_kw),
+			   p_opt_def("minconf", param_number, &minconf, 1),
+			   NULL)) {
+
+			/* For generating help, give new-style. */
+			if (!params || !deprecated_apis)
+				return command_param_failed();
+
+			/* For the old style:
+			 * *txprepare* 'destination' 'satoshi' ['feerate'] ['minconf'] */
 			if (!param(cmd, buffer, params,
 				   p_req("destination", param_bitcoin_address,
-			 &(*utx)->destination),
+					 &destination),
+				   p_req("satoshi", param_wtx, (*utx)->wtx),
+				   p_opt("feerate", param_feerate, &feerate_per_kw),
+				   p_opt_def("minconf", param_number, &minconf, 1),
+				   NULL))
+				/* If the parameters mixed the new style and the old style,
+				 * fail it. */
+				return command_param_failed();
+		}
+	} else {
+		/* *withdraw* command still use 'destination' and 'satoshi' as parameters. */
+		if (!param(cmd, buffer, params,
+			   p_req("destination", param_bitcoin_address,
+				 &destination),
 			   p_req("satoshi", param_wtx, (*utx)->wtx),
 			   p_opt("feerate", param_feerate, &feerate_per_kw),
 			   p_opt_def("minconf", param_number, &minconf, 1),
 			   NULL))
 		return command_param_failed();
-
+	}
-	/* Destination is owned by cmd: change that to be owned by utx. */
-	tal_steal(*utx, (*utx)->destination);
 
 	if (!feerate_per_kw) {
 		res = param_feerate_estimate(cmd, &feerate_per_kw,
@@ -191,11 +223,97 @@ static struct command_result *json_prepare_tx(struct command *cmd,
 	}
 
 	maxheight = minconf_to_maxheight(*minconf, cmd->ld);
+
+	/* *withdraw* command or old *txprepare* command.
+	 * Support only one output. */
+	if (destination) {
+		outputs = tal_arr(tmpctx, struct bitcoin_tx_output *, 1);
+		outputs[0] = tal(outputs, struct bitcoin_tx_output);
+		outputs[0]->script = tal_steal(outputs[0],
+					       cast_const(u8 *, destination));
+		outputs[0]->amount = (*utx)->wtx->amount;
+		out_len = tal_count(outputs[0]->script);
+
+		goto create_tx;
+	}
+
+	if (outputstok->size == 0)
+		return command_fail(cmd, JSONRPC2_INVALID_PARAMS, "Empty outputs");
+
+	outputs = tal_arr(tmpctx, struct bitcoin_tx_output *, outputstok->size);
+	out_len = 0;
+	(*utx)->wtx->all_funds = false;
+	(*utx)->wtx->amount = AMOUNT_SAT(0);
+	json_for_each_arr(i, t, outputstok) {
+		struct amount_sat *amount;
+		const u8 *destination;
+		enum address_parse_result res;
+
+		/* output format: {destination: amount} */
+		if (t->type != JSMN_OBJECT)
+			return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+					    "The output format must be "
+					    "{destination: amount}");;
+
+		res = json_tok_address_scriptpubkey(cmd,
+						    get_chainparams(cmd->ld),
+						    buffer, &t[1],
+						    &destination);
+		if (res == ADDRESS_PARSE_UNRECOGNIZED)
+			return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+					    "Could not parse destination address");
+		else if (res == ADDRESS_PARSE_WRONG_NETWORK)
+			return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+					    "Destination address is not on network %s",
+					    get_chainparams(cmd->ld)->network_name);
+
+		amount = tal(tmpctx, struct amount_sat);
+		if (!json_to_sat_or_all(buffer, &t[2], amount))
+			return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+					    "'%.*s' is a invalid satoshi amount",
+					    t[2].end - t[2].start, buffer + t[2].start);
+
+		out_len += tal_count(destination);
+		outputs[i] = tal(outputs, struct bitcoin_tx_output);
+		outputs[i]->amount = *amount;
+		outputs[i]->script = tal_steal(outputs[i],
+					       cast_const(u8 *, destination));
+
+		/* In fact, the maximum amount of bitcoin satoshi is 2.1e15.
+		 * It can't be equal to/bigger than 2^64.
+		 * On the hand, the maximum amount of litoshi is 8.4e15,
+		 * which also can't overflow. */
+		/* This means this destination need "all" satoshi we have. */
+		if (amount_sat_eq(*amount, AMOUNT_SAT(-1ULL))) {
+			if (outputstok->size > 1)
+				return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+						    "outputs[%zi]: this destination wants"
+						    " all satoshi. The count of outputs"
+						    " can't be more than 1. ", i);
+			(*utx)->wtx->all_funds = true;
+			/* `AMOUNT_SAT(-1ULL)` is the max permissible for `wallet_select_all`. */
+			(*utx)->wtx->amount = *amount;
+			break;
+		}
+
+		if (!amount_sat_add(&(*utx)->wtx->amount, (*utx)->wtx->amount, *amount))
+			return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+					    "outputs: The sum of first %zi outputs"
+					    " overflow. ", i);
+	}
+
+create_tx:
+	(*utx)->outputs = tal_steal(*utx, outputs);
 	res = wtx_select_utxos((*utx)->wtx, *feerate_per_kw,
-			       tal_count((*utx)->destination), maxheight);
+			       out_len, maxheight);
 	if (res)
 		return res;
 
+	/* Because of the max limit of AMOUNT_SAT(-1ULL),
+	 * `(*utx)->wtx->all_funds` won't change in `wtx_select_utxos()` */
+	if ((*utx)->wtx->all_funds)
+		outputs[0]->amount = (*utx)->wtx->amount;
+
 	if (!amount_sat_eq((*utx)->wtx->change, AMOUNT_SAT(0))) {
 		changekey = tal(tmpctx, struct pubkey);
 		if (!bip32_pubkey(cmd->ld->wallet->bip32_base, changekey,
@@ -203,15 +321,8 @@ static struct command_result *json_prepare_tx(struct command *cmd,
 			return command_fail(cmd, LIGHTNINGD, "Keys generation failure");
 	} else
 		changekey = NULL;
-
-	struct bitcoin_tx_output *output = tal(outputs,
-					       struct bitcoin_tx_output);
-	output->script = tal_dup_arr(output, u8, (*utx)->destination,
-				     tal_count((*utx)->destination), 0);
-	output->amount = (*utx)->wtx->amount;
-	tal_arr_expand(&outputs, output);
 	(*utx)->tx = withdraw_tx(*utx, get_chainparams(cmd->ld),
-				 (*utx)->wtx->utxos, outputs,
+				 (*utx)->wtx->utxos, (*utx)->outputs,
 				 changekey, (*utx)->wtx->change,
 				 cmd->ld->wallet->bip32_base,
 				 &(*utx)->change_outnum);
@@ -229,7 +340,7 @@ static struct command_result *json_txprepare(struct command *cmd,
 	struct command_result *res;
 	struct json_stream *response;
 
-	res = json_prepare_tx(cmd, buffer, params, &utx);
+	res = json_prepare_tx(cmd, buffer, params, &utx, false);
 	if (res)
 		return res;
 
@@ -352,7 +463,7 @@ static struct command_result *json_withdraw(struct command *cmd,
 	struct command_result *res;
 	struct bitcoin_txid txid;
 
-	res = json_prepare_tx(cmd, buffer, params, &utx);
+	res = json_prepare_tx(cmd, buffer, params, &utx, true);
 	if (res)
 		return res;
 

wire/fromwire.c

@@ -378,3 +378,14 @@ void fromwire_bip32_key_version(const u8** cursor, size_t *max,
 	version->bip32_pubkey_version = fromwire_u32(cursor, max);
 	version->bip32_privkey_version = fromwire_u32(cursor, max);
 }
+
+struct bitcoin_tx_output *fromwire_bitcoin_tx_output(const tal_t *ctx,
+						     const u8 **cursor, size_t *max)
+{
+	struct bitcoin_tx_output *output = tal(ctx, struct bitcoin_tx_output);
+	output->amount = fromwire_amount_sat(cursor, max);
+	u16 script_len = fromwire_u16(cursor, max);
+	output->script = tal_arr(output, u8, script_len);
+	fromwire_u8_array(cursor, max, output->script, script_len);
+	return output;
+}

wire/towire.c

@@ -249,3 +249,10 @@ void towire_bip32_key_version(u8 **pptr, const struct bip32_key_version *version
 	towire_u32(pptr, version->bip32_pubkey_version);
 	towire_u32(pptr, version->bip32_privkey_version);
 }
+
+void towire_bitcoin_tx_output(u8 **pptr, const struct bitcoin_tx_output *output)
+{
+	towire_amount_sat(pptr, output->amount);
+	towire_u16(pptr, tal_count(output->script));
+	towire_u8_array(pptr, output->script, tal_count(output->script));
+}

wire/wire.h

@@ -88,6 +88,7 @@ void towire_wirestring(u8 **pptr, const char *str);
 void towire_siphash_seed(u8 **cursor, const struct siphash_seed *seed);
 
 void towire_bip32_key_version(u8 **cursor, const struct bip32_key_version *version);
+void towire_bitcoin_tx_output(u8 **pptr, const struct bitcoin_tx_output *output);
 
 const u8 *fromwire(const u8 **cursor, size_t *max, void *copy, size_t n);
 u8 fromwire_u8(const u8 **cursor, size_t *max);
@@ -138,4 +139,6 @@ void fromwire_siphash_seed(const u8 **cursor, size_t *max,
 			   struct siphash_seed *seed);
 void fromwire_bip32_key_version(const u8 **cursor, size_t *max,
 				struct bip32_key_version *version);
+struct bitcoin_tx_output *fromwire_bitcoin_tx_output(const tal_t *ctx,
+						     const u8 **cursor, size_t *max);
 #endif /* LIGHTNING_WIRE_WIRE_H */