lightningd: convert the PSBTs dual-open commands and hooks take to version 2

lightningd/dual_open_control.c

@@ -447,7 +447,8 @@ hook_extract_psbt(const tal_t *ctx, struct subd *dualopend, const char *buffer,
 	}
 
 	*out = json_to_psbt(ctx, buffer, psbt_tok);
-	if (!*out)
+	/* We only deal in v2 */
+	if (!*out || !psbt_set_version(*out, 2))
 		fatal("Plugin must return a valid 'psbt' to a 'continue'd"
 		      "%s %.*s", hook_name,
 		      toks[0].end - toks[0].start,
@@ -2759,6 +2760,10 @@ json_openchannel_bump(struct command *cmd,
 			 NULL))
 		return command_param_failed();
 
+	/* We only deal in v2 */
+	if (!psbt_set_version(info->psbt, 2))
+		return command_fail(cmd, LIGHTNINGD, "Could not set PSBT version.");
+
 	psbt_val = AMOUNT_SAT(0);
 	for (size_t i = 0; i < info->psbt->num_inputs; i++) {
 		struct amount_sat in_amt = psbt_input_get_amount(info->psbt, i);
@@ -2931,6 +2936,10 @@ json_openchannel_signed(struct command *cmd,
 			 NULL))
 		return command_param_failed();
 
+	/* We only deal in v2 */
+	if (!psbt_set_version(psbt, 2))
+		return command_fail(cmd, LIGHTNINGD, "Could not set PSBT version.");
+
 	channel = channel_by_cid(cmd->ld, cid);
 	if (!channel)
 		return command_fail(cmd, FUNDING_UNKNOWN_CHANNEL,
@@ -3189,6 +3198,10 @@ static struct command_result *json_openchannel_update(struct command *cmd,
 			 NULL))
 		return command_param_failed();
 
+	/* We only deal in v2 */
+	if (!psbt_set_version(psbt, 2))
+		return command_fail(cmd, LIGHTNINGD, "Could not set PSBT version.");
+
 	channel = channel_by_cid(cmd->ld, cid);
 	if (!channel)
 		return command_fail(cmd, FUNDING_UNKNOWN_CHANNEL,

tests/plugins/df_accept_psbt_v0.py

@@ -0,0 +1,32 @@
+#!/usr/bin/env python3
+"""Accepts a dual-funded open with an input of our own, returning version 0
+PSBTs from the hooks, as an external wallet may."""
+
+from pyln.client import Plugin
+
+plugin = Plugin()
+
+
+@plugin.hook('openchannel2')
+def on_openchannel2(openchannel2, plugin, **kwargs):
+    psbt = plugin.rpc.call('fundpsbt', {
+        'satoshi': 100000,
+        'feerate': '{}perkw'.format(openchannel2['funding_feerate_per_kw']),
+        'startweight': 0,
+        'min_witness_weight': 110,
+        'excess_as_change': True,
+        'locktime': openchannel2['locktime'],
+        'nonwrapped': True})['psbt']
+    return {'result': 'continue',
+            'psbt': plugin.rpc.setpsbtversion(psbt, 0)['psbt'],
+            'our_funding_msat': 100000 * 1000}
+
+
+@plugin.hook('openchannel2_sign')
+def on_openchannel2_sign(openchannel2_sign, plugin, **kwargs):
+    signed = plugin.rpc.signpsbt(openchannel2_sign['psbt'])['signed_psbt']
+    return {'result': 'continue',
+            'psbt': plugin.rpc.setpsbtversion(signed, 0)['psbt']}
+
+
+plugin.run()

tests/test_opening.py

@@ -4403,3 +4403,68 @@ def test_duplicate_channel_id_in_db(node_factory, bitcoind):
     # And we can still start with both in the db.
     l2.restart()
     assert [c['channel_id'] for c in l2.rpc.listclosedchannels()['closedchannels']] == [cid, cid]
+
+
+@unittest.skipIf(TEST_NETWORK != 'regtest', 'elementsd doesnt yet support PSBT features we need')
+@pytest.mark.openchannel('v2')
+def test_v2_open_psbt_version_0(node_factory, bitcoind):
+    """openchannel_update and openchannel_signed, and the accepter's hooks,
+    take version 0 PSBTs, as openchannel_init already does."""
+    plugin = os.path.join(os.getcwd(), 'tests/plugins/df_accept_psbt_v0.py')
+    l1, l2 = node_factory.get_nodes(2, opts=[{},
+                                             {'plugin': plugin,
+                                              'disable-plugin': 'funder'}])
+    l1.fundwallet(2000000)
+    l2.fundwallet(2000000)
+    l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
+
+    def v0(psbt):
+        return l1.rpc.setpsbtversion(psbt, 0)['psbt']
+
+    psbt = l1.rpc.fundpsbt(500000, '7500perkw', 250, excess_as_change=True)['psbt']
+    start = l1.rpc.openchannel_init(l2.info['id'], 500000, v0(psbt))
+    chan_id = start['channel_id']
+    update = l1.rpc.openchannel_update(chan_id, v0(start['psbt']))
+    while not update['commitments_secured']:
+        update = l1.rpc.openchannel_update(chan_id, v0(update['psbt']))
+    l1.rpc.openchannel_signed(chan_id, v0(l1.rpc.signpsbt(update['psbt'])['signed_psbt']))
+    l1.daemon.wait_for_log(' to DUALOPEND_AWAITING_LOCKIN')
+
+    bitcoind.generate_block(6, wait_for_mempool=1)
+    for n in (l1, l2):
+        n.daemon.wait_for_log(' to CHANNELD_NORMAL')
+    funding = only_one(l1.rpc.listpeerchannels()['channels'])['funding']
+    assert funding['remote_funds_msat'] == Millisatoshi(100000 * 1000)
+
+
+@unittest.skipIf(TEST_NETWORK != 'regtest', 'elementsd doesnt yet support PSBT features we need')
+@pytest.mark.openchannel('v2')
+def test_v2_rbf_psbt_version_0(node_factory, bitcoind):
+    """openchannel_bump takes a version 0 PSBT."""
+    l1, l2 = node_factory.get_nodes(2)
+    l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
+    chan_amount = 100000
+    l1.fundwallet(2**24)
+
+    def v0(psbt):
+        return l1.rpc.setpsbtversion(psbt, 0)['psbt']
+
+    res = l1.rpc.fundchannel(l2.info['id'], chan_amount)
+    chan_id = res['channel_id']
+    vin = only_one(bitcoind.rpc.decoderawtransaction(res['tx'])['vin'])
+    l1.daemon.wait_for_log(' to DUALOPEND_AWAITING_LOCKIN')
+
+    startweight = 42 + 172  # base weight, funding output
+    initpsbt = l1.rpc.utxopsbt(chan_amount, find_next_feerate(l1, l2), startweight,
+                               ["{}:{}".format(vin['txid'], vin['vout'])],
+                               reservedok=True, excess_as_change=True)['psbt']
+    bump = l1.rpc.openchannel_bump(chan_id, chan_amount, v0(initpsbt))
+    update = l1.rpc.openchannel_update(chan_id, v0(bump['psbt']))
+    assert update['commitments_secured']
+    l1.rpc.openchannel_signed(chan_id, v0(l1.rpc.signpsbt(update['psbt'])['signed_psbt']))
+
+    bitcoind.generate_block(6, wait_for_mempool=1)
+    for n in (l1, l2):
+        n.daemon.wait_for_log(' to CHANNELD_NORMAL')
+    # The bump is what confirmed.
+    assert only_one(l1.rpc.listpeerchannels()['channels'])['funding_txid'] != res['txid']