dualfund: add test to make sure that tx-sigs sent before commitment

results in an error.

common/dev_disconnect.c

@@ -70,7 +70,8 @@ enum dev_disconnect dev_disconnect(const struct node_id *id, int pkt_type)
 		err(1, "lseek failure");
 	}
 
-	status_peer_debug(id, "dev_disconnect: %s (%s)", dev_disconnect_line,
+	status_peer_debug(id, "dev_disconnect: %s (%s)",
+			  dev_disconnect_line,
 			  peer_wire_name(pkt_type));
 	return dev_disconnect_line[0];
 }

common/dev_disconnect.h

@@ -12,6 +12,8 @@ enum dev_disconnect {
 	DEV_DISCONNECT_BEFORE = '-',
 	/* Close connection after sending packet. */
 	DEV_DISCONNECT_AFTER = '+',
+	/* Drop message (don't send to peer) */
+	DEV_DISCONNECT_DROP = '$',
 	/* Swallow all writes from now on, and do no more reads. */
 	DEV_DISCONNECT_BLACKHOLE = '0',
 	/* Don't use connection after sending packet, but don't close. */

connectd/multiplex.c

@@ -446,6 +446,14 @@ static struct io_plan *encrypt_and_send(struct peer *peer,
 		break;
 	case DEV_DISCONNECT_NORMAL:
 		break;
+	case DEV_DISCONNECT_DROP:
+		/* Drop this message and continue */
+		if (taken(msg))
+			tal_free(msg);
+		/* Tell them to read again, */
+		io_wake(&peer->subds);
+		return msg_queue_wait(peer->to_peer, peer->peer_outq,
+				      next, peer);
 	case DEV_DISCONNECT_DISABLE_AFTER:
 		peer->dev_read_enabled = false;
 		peer->dev_writes_enabled = tal(peer, u32);

connectd/peer_exchange_initmsg.c

@@ -288,6 +288,7 @@ struct io_plan *peer_exchange_initmsg(struct io_conn *conn,
 			      "Blackhole not supported during handshake");
 		break;
 	case DEV_DISCONNECT_NORMAL:
+	case DEV_DISCONNECT_DROP:
 		break;
 	case DEV_DISCONNECT_DISABLE_AFTER:
 		next = dev_peer_write_post_sabotage;

openingd/dualopend.c

@@ -1628,7 +1628,6 @@ static u8 *opening_negotiate_msg(const tal_t *ctx, struct state *state)
 		case WIRE_TX_SIGNATURES:
 			/* We can get these when we restart and immediately
 			 * startup an RBF */
-
 			handle_tx_sigs(state, msg);
 			continue;
 		case WIRE_CHANNEL_READY:

tests/test_opening.py

@@ -216,6 +216,38 @@ def test_v2_open_sigs_reconnect_1(node_factory, bitcoind):
     l2.daemon.wait_for_log(r'to CHANNELD_NORMAL')
 
 
+@unittest.skipIf(TEST_NETWORK != 'regtest', 'elementsd doesnt yet support PSBT features we need')
+@pytest.mark.xfail
+@pytest.mark.openchannel('v2')
+def test_v2_open_sigs_out_of_order(node_factory, bitcoind):
+    """ Test what happens if the tx-sigs get sent "before" commitment signed """
+    disconnects = ['$WIRE_COMMITMENT_SIGNED']
+
+    l1, l2 = node_factory.get_nodes(2,
+                                    opts=[{},
+                                          {'disconnect': disconnects}])
+
+    l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
+    amount = 2**24
+    chan_amount = 100000
+    bitcoind.rpc.sendtoaddress(l1.rpc.newaddr()['bech32'], amount / 10**8 + 0.01)
+    bitcoind.generate_block(1)
+    # Wait for it to arrive.
+    wait_for(lambda: len(l1.rpc.listfunds()['outputs']) > 0)
+
+    # Fund the channel, should error because L2 doesn't see our commitment-signed
+    # so they think we've sent things out of order
+    with pytest.raises(RpcError, match='tx_signatures sent before commitment sigs'):
+        l1.rpc.fundchannel(l2.info['id'], chan_amount)
+
+    # L1 should remove the in-progress channel
+    wait_for(lambda: l1.rpc.listpeerchannels()['channels'] == [])
+    # L2 should fail it to chain
+    l2.daemon.wait_for_logs([r'to AWAITING_UNILATERAL',
+                             # We can't broadcast this, we don't have sigs for funding
+                             'sendrawtx exit 25'])
+
+
 @pytest.mark.openchannel('v2')
 def test_v2_fail_second(node_factory, bitcoind):
     """ Open a channel succeeds; opening a second channel