fundchannel: add txout field to RPC/API

We'll need the outpoint for the funding output.

contrib/pylightning/lightning/lightning.py

@@ -499,13 +499,14 @@ class LightningRpc(UnixDomainSocketRpc):
         }
         return self.call("fundchannel_start", payload)
 
-    def fundchannel_continue(self, node_id, funding_txid):
+    def fundchannel_continue(self, node_id, funding_txid, funding_txout):
         """
-        Complete channel establishment with {id}, using {funding_txid}
+        Complete channel establishment with {id}, using {funding_txid} at {funding_txout}
         """
         payload = {
             "id": node_id,
             "txid": funding_txid,
+            "txout": funding_txout,
         }
         return self.call("fundchannel_continue", payload)
 

lightningd/opening_control.c

@@ -364,6 +364,7 @@ static void opening_funder_finished(struct subd *openingd, const u8 *resp,
 					   &fc->uc->minimum_depth,
 					   &channel_info.remote_fundingkey,
 					   &expected_txid,
+					   &funding_outnum,
 					   &feerate,
 					   &fc->uc->our_config.channel_reserve,
 					   &remote_upfront_shutdown_script)) {
@@ -1056,13 +1057,22 @@ static struct command_result *json_fund_channel_continue(struct command *cmd,
 	struct bitcoin_txid *funding_txid;
 	struct peer *peer;
 	struct channel *channel;
+	u32 *funding_txout_num;
+	u16 funding_txout;
 
 	if (!param(cmd, buffer, params,
 		   p_req("id", param_node_id, &id),
 		   p_req("txid", param_txid, &funding_txid),
+		   p_req("txout", param_number, &funding_txout_num),
 		   NULL))
 		return command_param_failed();
 
+	if (*funding_txout_num > UINT16_MAX)
+		return command_fail(cmd, LIGHTNINGD,
+				    "Invalid parameter: funding tx vout too large %u",
+				    *funding_txout_num);
+
+	funding_txout = *funding_txout_num;
 	peer = peer_by_id(cmd->ld, id);
 	if (!peer) {
 		return command_fail(cmd, LIGHTNINGD, "Unknown peer");
@@ -1079,7 +1089,9 @@ static struct command_result *json_fund_channel_continue(struct command *cmd,
 	if (!peer->uncommitted_channel->fc)
 		return command_fail(cmd, LIGHTNINGD, "No channel funding in progress.");
 
-	msg = towire_opening_funder_continue(NULL, funding_txid);
+	msg = towire_opening_funder_continue(NULL,
+					     funding_txid,
+					     funding_txout);
 	subd_send_msg(peer->uncommitted_channel->openingd, take(msg));
 	return command_still_pending(cmd);
 }

openingd/opening_wire.csv

@@ -72,6 +72,7 @@ opening_funder_reply,,their_per_commit_point,struct pubkey
 opening_funder_reply,,minimum_depth,u32
 opening_funder_reply,,remote_fundingkey,struct pubkey
 opening_funder_reply,,funding_txid,struct bitcoin_txid
+opening_funder_reply,,funding_txout,u16
 opening_funder_reply,,feerate_per_kw,u32
 opening_funder_reply,,our_channel_reserve_satoshis,struct amount_sat
 opening_funder_reply,,shutdown_len,u16
@@ -90,11 +91,12 @@ opening_funder_start_reply,6102
 opening_funder_start_reply,,script_len,u8
 opening_funder_start_reply,,scriptpubkey,script_len*u8
 
-# master->openingd: continue channel establsihment for a funding
+# master->openingd: continue channel establishment for a funding
 # tx that will be paid for by an external wallet
 # response to this is a normal `opening_funder_reply` ??
 opening_funder_continue,6012
 opening_funder_continue,,funding_txid,struct bitcoin_txid
+opening_funder_continue,,funding_txout,u16
 
 # Openingd->master: we failed to negotiation channel
 opening_funder_failed,6004

openingd/openingd.c

@@ -1038,6 +1038,7 @@ static u8 *funder_channel(struct state *state,
 					   minimum_depth,
 					   &their_funding_pubkey,
 					   &state->funding_txid,
+					   state->funding_txout,
 					   state->feerate_per_kw,
 					   state->localconf.channel_reserve,
 					   state->remote_upfront_shutdown_script);
@@ -1573,6 +1574,7 @@ static u8 *handle_master_in(struct state *state)
 	u32 change_keyindex;
 	u8 channel_flags;
 	struct bitcoin_txid funding_txid;
+	u16 funding_txout;
 	struct utxo **utxos;
 	struct ext_key bip32_base;
 
@@ -1606,7 +1608,8 @@ static u8 *handle_master_in(struct state *state)
 		return NULL;
 	case WIRE_OPENING_FUNDER_CONTINUE:
 		if (!fromwire_opening_funder_continue(msg,
-						      &funding_txid))
+						      &funding_txid,
+						      &funding_txout))
 			master_badmsg(WIRE_OPENING_FUNDER_CONTINUE, msg);
 		return funder_channel_continue(state, &funding_txid);
 	case WIRE_OPENING_DEV_MEMLEAK:

tests/test_connection.py

@@ -831,17 +831,18 @@ def test_funding_external_wallet_corners(node_factory, bitcoind):
 
     amount = amount - 1
     fake_txid = '929764844a8f9938b669a60a1d51a11c9e2613c7eb4776e4126f1f20c0a685c3'
+    fake_txout = 0
 
     with pytest.raises(RpcError, match=r'Unknown peer'):
         l1.rpc.fundchannel_start(l2.info['id'], amount)
 
     with pytest.raises(RpcError, match=r'Unknown peer'):
-        l1.rpc.fundchannel_continue(l2.info['id'], fake_txid)
+        l1.rpc.fundchannel_continue(l2.info['id'], fake_txid, fake_txout)
 
     # Should not be able to continue without being in progress.
     l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
     with pytest.raises(RpcError, match=r'No channel funding in progress.'):
-        l1.rpc.fundchannel_continue(l2.info['id'], fake_txid)
+        l1.rpc.fundchannel_continue(l2.info['id'], fake_txid, fake_txout)
 
 
 def test_funding_external_wallet(node_factory, bitcoind):