dual-fund: test (turned off) and plugin for executing an openchannel

Proof that v2 openchannel works, plus a plugin for sewing all the
requisite bits together

tests/plugins/df_opener.py

@@ -0,0 +1,87 @@
+#!/usr/bin/env python3
+"""Test plugin for executing the opener v2 protocol
+"""
+from pyln.client import Plugin, Millisatoshi
+from pyln.proto import bech32_decode
+from typing import Iterable, List, Optional
+from wallycore import psbt_add_output_at, psbt_from_base64, psbt_to_base64, tx_output_init
+
+
+plugin = Plugin()
+
+
+def convertbits(data: Iterable[int], frombits: int, tobits: int, pad: bool = True) -> Optional[List[int]]:
+    """General power-of-2 base conversion."""
+    acc = 0
+    bits = 0
+    ret = []
+    maxv = (1 << tobits) - 1
+    max_acc = (1 << (frombits + tobits - 1)) - 1
+    for value in data:
+        if value < 0 or (value >> frombits):
+            return None
+        acc = ((acc << frombits) | value) & max_acc
+        bits += frombits
+        while bits >= tobits:
+            bits -= tobits
+            ret.append((acc >> bits) & maxv)
+    if pad:
+        if bits:
+            ret.append((acc << (tobits - bits)) & maxv)
+    elif bits >= frombits or ((acc << (tobits - bits)) & maxv):
+        return None
+    return ret
+
+
+def get_script(bech_addr):
+    hrp, data = bech32_decode(bech_addr)
+    # FIXME: verify hrp matches expected network
+    wprog = convertbits(data[1:], 5, 8, False)
+    wit_ver = data[0]
+    if wit_ver > 16:
+        raise ValueError("Invalid witness version {}".format(wit_ver[0]))
+    return bytes([wit_ver + 0x50 if wit_ver > 0 else wit_ver, len(wprog)] + wprog)
+
+
+@plugin.method('openchannelv2')
+def openchannel_v2(plugin, node_id, amount):
+    change_output_weight = (9 + 22) * 4
+    funding_output_weight = (9 + 34) * 4
+    core_weight = 44
+    feerate_val = 2000
+    feerate = '{}perkw'.format(feerate_val)
+
+    funding = plugin.rpc.fundpsbt(amount, feerate, funding_output_weight + core_weight)
+    psbt_obj = psbt_from_base64(funding['psbt'])
+
+    excess = Millisatoshi(funding['excess_msat'])
+    # FIXME: convert feerate ?!
+    change_cost = Millisatoshi(change_output_weight * feerate_val // 1000 * 1000)
+    dust_limit = Millisatoshi(feerate_val * 1000)
+    if excess > (dust_limit + change_cost):
+        addr = plugin.rpc.newaddr()['bech32']
+        change = excess - change_cost
+        output = tx_output_init(int(change.to_satoshi()), get_script(addr))
+        psbt_add_output_at(psbt_obj, 0, 0, output)
+
+    resp = plugin.rpc.openchannel_init(node_id, amount,
+                                       psbt_to_base64(psbt_obj, 0),
+                                       commitment_feerate=feerate,
+                                       funding_feerate=feerate)
+
+    # We don't have an updates, so we send update until our peer is also
+    # finished
+    while not resp['commitments_secured']:
+        resp = plugin.rpc.openchannel_update(node_id, resp['psbt'])
+
+    # fixme: pass in array of our input indexes to signonly
+    signed = plugin.rpc.signpsbt(resp['psbt'])
+    return plugin.rpc.openchannel_signed(node_id, signed['signed_psbt'])
+
+
+@plugin.init()
+def init(options, configuration, plugin):
+    plugin.log("df_opener.py initializing")
+
+
+plugin.run()

tests/test_connection.py

@@ -819,6 +819,27 @@ def test_funding_toolarge(node_factory, bitcoind):
     l1.rpc.fundchannel(l2.info['id'], amount)
 
 
+@unittest.skipIf(not EXPERIMENTAL_FEATURES, "dual-funding is experimental only")
+@unittest.skipIf(True, "df_opener.py requires wallycore")
+def test_v2_open(node_factory, bitcoind, chainparams):
+    l1 = node_factory.get_node(options={'plugin': os.path.join(os.getcwd(),
+                                        'tests/plugins/df_opener.py')})
+    l2 = node_factory.get_node()
+
+    l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
+    amount = 2**24
+    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)
+
+    l1.rpc.openchannelv2(l2.info['id'], 100000)
+
+    bitcoind.generate_block(1)
+    sync_blockheight(bitcoind, [l1])
+    l1.daemon.wait_for_log(' to CHANNELD_NORMAL')
+
+
 def test_funding_push(node_factory, bitcoind, chainparams):
     """ Try to push peer some sats """
     # We track balances, to verify that accounting is ok.