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#!/usr/bin/env python3
#
# Copyright (C) 2018 The Electrum developers
# Distributed under the MIT software license, see the accompanying
# file LICENCE or http://www.opensource.org/licenses/mit-license.php
import zlib
from collections import OrderedDict, defaultdict
import json
import asyncio
import os
import time
from functools import partial
from typing import List, Tuple, Dict, TYPE_CHECKING, Optional, Callable, Union
import traceback
import sys
from datetime import datetime
import aiorpcx
from .crypto import sha256, sha256d
from . import bitcoin
from . import ecc
from .ecc import sig_string_from_r_and_s, get_r_and_s_from_sig_string, der_sig_from_sig_string
from . import constants
from .util import bh2u, bfh, log_exceptions, list_enabled_bits, ignore_exceptions, chunks, SilentTaskGroup
from .transaction import Transaction, TxOutput, PartialTxOutput
from .logging import Logger
from .lnonion import (new_onion_packet, decode_onion_error, OnionFailureCode, calc_hops_data_for_payment,
process_onion_packet, OnionPacket, construct_onion_error, OnionRoutingFailureMessage,
ProcessedOnionPacket)
from .lnchannel import Channel, RevokeAndAck, htlcsum, RemoteCtnTooFarInFuture, channel_states, peer_states
from . import lnutil
from .lnutil import (Outpoint, LocalConfig, RECEIVED, UpdateAddHtlc,
RemoteConfig, OnlyPubkeyKeypair, ChannelConstraints, RevocationStore,
funding_output_script, get_per_commitment_secret_from_seed,
secret_to_pubkey, PaymentFailure, LnLocalFeatures,
LOCAL, REMOTE, HTLCOwner, generate_keypair, LnKeyFamily,
get_ln_flag_pair_of_bit, privkey_to_pubkey, UnknownPaymentHash, MIN_FINAL_CLTV_EXPIRY_ACCEPTED,
LightningPeerConnectionClosed, HandshakeFailed, NotFoundChanAnnouncementForUpdate,
MINIMUM_MAX_HTLC_VALUE_IN_FLIGHT_ACCEPTED, MAXIMUM_HTLC_MINIMUM_MSAT_ACCEPTED,
MAXIMUM_REMOTE_TO_SELF_DELAY_ACCEPTED, RemoteMisbehaving, DEFAULT_TO_SELF_DELAY,
NBLOCK_OUR_CLTV_EXPIRY_DELTA, format_short_channel_id, ShortChannelID)
from .lnutil import FeeUpdate
from .lntransport import LNTransport, LNTransportBase
from .lnmsg import encode_msg, decode_msg
from .interface import GracefulDisconnect, NetworkException
from .lnrouter import fee_for_edge_msat
from .lnutil import ln_dummy_address
if TYPE_CHECKING:
from .lnworker import LNWorker, LNGossip, LNWallet
from .lnrouter import RouteEdge, LNPaymentRoute
from .transaction import PartialTransaction
LN_P2P_NETWORK_TIMEOUT = 20
def channel_id_from_funding_tx(funding_txid: str, funding_index: int) -> Tuple[bytes, bytes]:
funding_txid_bytes = bytes.fromhex(funding_txid)[::-1]
i = int.from_bytes(funding_txid_bytes, 'big') ^ funding_index
return i.to_bytes(32, 'big'), funding_txid_bytes
class Peer(Logger):
def __init__(self, lnworker: Union['LNGossip', 'LNWallet'], pubkey:bytes, transport: LNTransportBase):
self._sent_init = False # type: bool
self._received_init = False # type: bool
self.initialized = asyncio.Event()
self.querying = asyncio.Event()
self.transport = transport
self.pubkey = pubkey # remote pubkey
self.lnworker = lnworker
self.privkey = lnworker.node_keypair.privkey # local privkey
self.localfeatures = self.lnworker.localfeatures
self.node_ids = [self.pubkey, privkey_to_pubkey(self.privkey)]
self.network = lnworker.network
self.channel_db = lnworker.network.channel_db
self.ping_time = 0
self.reply_channel_range = asyncio.Queue()
# gossip uses a single queue to preserve message order
self.gossip_queue = asyncio.Queue()
# channel messsage queues
self.shutdown_received = defaultdict(asyncio.Future)
self.channel_accepted = defaultdict(asyncio.Queue)
self.channel_reestablished = defaultdict(asyncio.Queue)
self.funding_signed = defaultdict(asyncio.Queue)
self.funding_created = defaultdict(asyncio.Queue)
self.announcement_signatures = defaultdict(asyncio.Queue)
self.closing_signed = defaultdict(asyncio.Queue)
#
self.orphan_channel_updates = OrderedDict()
self._local_changed_events = defaultdict(asyncio.Event)
self._remote_changed_events = defaultdict(asyncio.Event)
Logger.__init__(self)
self.group = SilentTaskGroup()
def send_message(self, message_name: str, **kwargs):
assert type(message_name) is str
self.logger.debug(f"Sending {message_name.upper()}")
if message_name.upper() != "INIT" and not self.initialized.is_set():
raise Exception("tried to send message before we are initialized")
raw_msg = encode_msg(message_name, **kwargs)
self._store_raw_msg_if_local_update(raw_msg, message_name=message_name, channel_id=kwargs.get("channel_id"))
self.transport.send_bytes(raw_msg)
def _store_raw_msg_if_local_update(self, raw_msg: bytes, *, message_name: str, channel_id: Optional[bytes]):
is_commitment_signed = message_name == "commitment_signed"
if not (message_name.startswith("update_") or is_commitment_signed):
return
assert channel_id
chan = self.lnworker.channels[channel_id] # type: Channel
chan.hm.store_local_update_raw_msg(raw_msg, is_commitment_signed=is_commitment_signed)
if is_commitment_signed:
# saving now, to ensure replaying updates works (in case of channel reestablishment)
self.lnworker.save_channel(chan)
async def initialize(self):
if isinstance(self.transport, LNTransport):
await self.transport.handshake()
self.send_message("init", gflen=0, lflen=1, localfeatures=self.localfeatures)
self._sent_init = True
@property
def channels(self) -> Dict[bytes, Channel]:
return self.lnworker.channels_for_peer(self.pubkey)
def diagnostic_name(self):
return self.transport.name()
def ping_if_required(self):
if time.time() - self.ping_time > 120:
self.send_message('ping', num_pong_bytes=4, byteslen=4)
self.ping_time = time.time()
def process_message(self, message):
message_type, payload = decode_msg(message)
try:
f = getattr(self, 'on_' + message_type)
except AttributeError:
#self.logger.info("Received '%s'" % message_type.upper(), payload)
return
# raw message is needed to check signature
if message_type in ['node_announcement', 'channel_announcement', 'channel_update']:
payload['raw'] = message
execution_result = f(payload)
if asyncio.iscoroutinefunction(f):
asyncio.ensure_future(execution_result)
def on_error(self, payload):
self.logger.info(f"on_error: {payload['data'].decode('ascii')}")
chan_id = payload.get("channel_id")
for d in [ self.channel_accepted, self.funding_signed,
self.funding_created, self.channel_reestablished,
self.announcement_signatures, self.closing_signed ]:
if chan_id in d:
d[chan_id].put_nowait({'error':payload['data']})
def on_ping(self, payload):
l = int.from_bytes(payload['num_pong_bytes'], 'big')
self.send_message('pong', byteslen=l)
def on_pong(self, payload):
pass
def on_accept_channel(self, payload):
temp_chan_id = payload["temporary_channel_id"]
if temp_chan_id not in self.channel_accepted:
raise Exception("Got unknown accept_channel")
self.channel_accepted[temp_chan_id].put_nowait(payload)
def on_funding_signed(self, payload):
channel_id = payload['channel_id']
if channel_id not in self.funding_signed: raise Exception("Got unknown funding_signed")
self.funding_signed[channel_id].put_nowait(payload)
def on_funding_created(self, payload):
channel_id = payload['temporary_channel_id']
if channel_id not in self.funding_created: raise Exception("Got unknown funding_created")
self.funding_created[channel_id].put_nowait(payload)
def on_init(self, payload):
if self._received_init:
self.logger.info("ALREADY INITIALIZED BUT RECEIVED INIT")
return
# if they required some even flag we don't have, they will close themselves
# but if we require an even flag they don't have, we close
their_localfeatures = int.from_bytes(payload['localfeatures'], byteorder="big")
our_flags = set(list_enabled_bits(self.localfeatures))
their_flags = set(list_enabled_bits(their_localfeatures))
for flag in our_flags:
if flag not in their_flags and get_ln_flag_pair_of_bit(flag) not in their_flags:
# they don't have this feature we wanted :(
if flag % 2 == 0: # even flags are compulsory
raise GracefulDisconnect("remote does not have even flag {}"
.format(str(LnLocalFeatures(1 << flag))))
self.localfeatures ^= 1 << flag # disable flag
else:
# They too have this flag.
# For easier feature-bit-testing, if this is an even flag, we also
# set the corresponding odd flag now.
if flag % 2 == 0 and self.localfeatures & (1 << flag):
self.localfeatures |= 1 << get_ln_flag_pair_of_bit(flag)
if isinstance(self.transport, LNTransport):
self.channel_db.add_recent_peer(self.transport.peer_addr)
self._received_init = True
if self._sent_init and self._received_init:
self.initialized.set()
def on_node_announcement(self, payload):
self.gossip_queue.put_nowait(('node_announcement', payload))
def on_channel_announcement(self, payload):
self.gossip_queue.put_nowait(('channel_announcement', payload))
def on_channel_update(self, payload):
self.maybe_save_remote_update(payload)
self.gossip_queue.put_nowait(('channel_update', payload))
def maybe_save_remote_update(self, payload):
for chan in self.channels.values():
if chan.short_channel_id == payload['short_channel_id']:
chan.remote_update = payload['raw']
self.logger.info("saved remote_update")
def on_announcement_signatures(self, payload):
channel_id = payload['channel_id']
chan = self.channels[payload['channel_id']]
if chan.config[LOCAL].was_announced:
h, local_node_sig, local_bitcoin_sig = self.send_announcement_signatures(chan)
else:
self.announcement_signatures[channel_id].put_nowait(payload)
def handle_disconnect(func):
async def wrapper_func(self, *args, **kwargs):
try:
return await func(self, *args, **kwargs)
except GracefulDisconnect as e:
self.logger.log(e.log_level, f"Disconnecting: {repr(e)}")
except LightningPeerConnectionClosed as e:
self.logger.info(f"Disconnecting: {repr(e)}")
finally:
self.close_and_cleanup()
return wrapper_func
@ignore_exceptions # do not kill main_taskgroup
@log_exceptions
@handle_disconnect
async def main_loop(self):
async with self.group as group:
await group.spawn(self._message_loop())
await group.spawn(self.query_gossip())
await group.spawn(self.process_gossip())
async def process_gossip(self):
await self.channel_db.data_loaded.wait()
# verify in peer's TaskGroup so that we fail the connection
while True:
await asyncio.sleep(5)
chan_anns = []
chan_upds = []
node_anns = []
while True:
name, payload = await self.gossip_queue.get()
if name == 'channel_announcement':
chan_anns.append(payload)
elif name == 'channel_update':
chan_upds.append(payload)
elif name == 'node_announcement':
node_anns.append(payload)
else:
raise Exception('unknown message')
if self.gossip_queue.empty():
break
self.logger.debug(f'process_gossip {len(chan_anns)} {len(node_anns)} {len(chan_upds)}')
# note: data processed in chunks to avoid taking sql lock for too long
# channel announcements
for chan_anns_chunk in chunks(chan_anns, 300):
self.verify_channel_announcements(chan_anns_chunk)
self.channel_db.add_channel_announcement(chan_anns_chunk)
# node announcements
for node_anns_chunk in chunks(node_anns, 100):
self.verify_node_announcements(node_anns_chunk)
self.channel_db.add_node_announcement(node_anns_chunk)
# channel updates
for chan_upds_chunk in chunks(chan_upds, 1000):
categorized_chan_upds = self.channel_db.add_channel_updates(
chan_upds_chunk, max_age=self.network.lngossip.max_age)
orphaned = categorized_chan_upds.orphaned
if orphaned:
self.logger.info(f'adding {len(orphaned)} unknown channel ids')
orphaned_ids = [c['short_channel_id'] for c in orphaned]
await self.network.lngossip.add_new_ids(orphaned_ids)
# Save (some bounded number of) orphan channel updates for later
# as it might be for our own direct channel with this peer
# (and we might not yet know the short channel id for that)
for chan_upd_payload in orphaned:
short_channel_id = ShortChannelID(chan_upd_payload['short_channel_id'])
self.orphan_channel_updates[short_channel_id] = chan_upd_payload
while len(self.orphan_channel_updates) > 25:
self.orphan_channel_updates.popitem(last=False)
if categorized_chan_upds.good:
self.logger.debug(f'on_channel_update: {len(categorized_chan_upds.good)}/{len(chan_upds_chunk)}')
def verify_channel_announcements(self, chan_anns):
for payload in chan_anns:
h = sha256d(payload['raw'][2+256:])
pubkeys = [payload['node_id_1'], payload['node_id_2'], payload['bitcoin_key_1'], payload['bitcoin_key_2']]
sigs = [payload['node_signature_1'], payload['node_signature_2'], payload['bitcoin_signature_1'], payload['bitcoin_signature_2']]
for pubkey, sig in zip(pubkeys, sigs):
if not ecc.verify_signature(pubkey, sig, h):
raise Exception('signature failed')
def verify_node_announcements(self, node_anns):
for payload in node_anns:
pubkey = payload['node_id']
signature = payload['signature']
h = sha256d(payload['raw'][66:])
if not ecc.verify_signature(pubkey, signature, h):
raise Exception('signature failed')
async def query_gossip(self):
try:
await asyncio.wait_for(self.initialized.wait(), LN_P2P_NETWORK_TIMEOUT)
except asyncio.TimeoutError as e:
raise GracefulDisconnect("initialize timed out") from e
if self.lnworker == self.lnworker.network.lngossip:
try:
ids, complete = await asyncio.wait_for(self.get_channel_range(), LN_P2P_NETWORK_TIMEOUT)
except asyncio.TimeoutError as e:
raise GracefulDisconnect("query_channel_range timed out") from e
self.logger.info('Received {} channel ids. (complete: {})'.format(len(ids), complete))
await self.lnworker.add_new_ids(ids)
while True:
todo = self.lnworker.get_ids_to_query()
if not todo:
await asyncio.sleep(1)
continue
await self.get_short_channel_ids(todo)
async def get_channel_range(self):
first_block = constants.net.BLOCK_HEIGHT_FIRST_LIGHTNING_CHANNELS
num_blocks = self.lnworker.network.get_local_height() - first_block
self.query_channel_range(first_block, num_blocks)
intervals = []
ids = set()
# note: implementations behave differently...
# "sane implementation that follows BOLT-07" example:
# query_channel_range. <<< first_block 497000, num_blocks 79038
# on_reply_channel_range. >>> first_block 497000, num_blocks 39516, num_ids 4648, complete True
# on_reply_channel_range. >>> first_block 536516, num_blocks 19758, num_ids 5734, complete True
# on_reply_channel_range. >>> first_block 556274, num_blocks 9879, num_ids 13712, complete True
# on_reply_channel_range. >>> first_block 566153, num_blocks 9885, num_ids 18114, complete True
# lnd example:
# query_channel_range. <<< first_block 497000, num_blocks 79038
# on_reply_channel_range. >>> first_block 497000, num_blocks 79038, num_ids 8000, complete False
# on_reply_channel_range. >>> first_block 497000, num_blocks 79038, num_ids 8000, complete False
# on_reply_channel_range. >>> first_block 497000, num_blocks 79038, num_ids 8000, complete False
# on_reply_channel_range. >>> first_block 497000, num_blocks 79038, num_ids 8000, complete False
# on_reply_channel_range. >>> first_block 497000, num_blocks 79038, num_ids 5344, complete True
while True:
index, num, complete, _ids = await self.reply_channel_range.get()
ids.update(_ids)
intervals.append((index, index+num))
intervals.sort()
while len(intervals) > 1:
a,b = intervals[0]
c,d = intervals[1]
if not (a <= c and a <= b and c <= d):
raise Exception(f"insane reply_channel_range intervals {(a,b,c,d)}")
if b >= c:
intervals = [(a,d)] + intervals[2:]
else:
break
if len(intervals) == 1 and complete:
a, b = intervals[0]
if a <= first_block and b >= first_block + num_blocks:
break
return ids, complete
def request_gossip(self, timestamp=0):
if timestamp == 0:
self.logger.info('requesting whole channel graph')
else:
self.logger.info(f'requesting channel graph since {datetime.fromtimestamp(timestamp).ctime()}')
self.send_message(
'gossip_timestamp_filter',
chain_hash=constants.net.rev_genesis_bytes(),
first_timestamp=timestamp,
timestamp_range=b'\xff'*4)
def query_channel_range(self, first_block, num_blocks):
self.logger.info(f'query channel range {first_block} {num_blocks}')
self.send_message(
'query_channel_range',
chain_hash=constants.net.rev_genesis_bytes(),
first_blocknum=first_block,
number_of_blocks=num_blocks)
def encode_short_ids(self, ids):
return chr(1) + zlib.compress(bfh(''.join(ids)))
def decode_short_ids(self, encoded):
if encoded[0] == 0:
decoded = encoded[1:]
elif encoded[0] == 1:
decoded = zlib.decompress(encoded[1:])
else:
raise Exception(f'decode_short_ids: unexpected first byte: {encoded[0]}')
ids = [decoded[i:i+8] for i in range(0, len(decoded), 8)]
return ids
def on_reply_channel_range(self, payload):
first = int.from_bytes(payload['first_blocknum'], 'big')
num = int.from_bytes(payload['number_of_blocks'], 'big')
complete = bool(int.from_bytes(payload['complete'], 'big'))
encoded = payload['encoded_short_ids']
ids = self.decode_short_ids(encoded)
#self.logger.info(f"on_reply_channel_range. >>> first_block {first}, num_blocks {num}, num_ids {len(ids)}, complete {repr(payload['complete'])}")
self.reply_channel_range.put_nowait((first, num, complete, ids))
async def get_short_channel_ids(self, ids):
self.logger.info(f'Querying {len(ids)} short_channel_ids')
assert not self.querying.is_set()
self.query_short_channel_ids(ids)
await self.querying.wait()
self.querying.clear()
def query_short_channel_ids(self, ids, compressed=True):
ids = sorted(ids)
s = b''.join(ids)
encoded = zlib.compress(s) if compressed else s
prefix = b'\x01' if compressed else b'\x00'
self.send_message(
'query_short_channel_ids',
chain_hash=constants.net.rev_genesis_bytes(),
len=1+len(encoded),
encoded_short_ids=prefix+encoded)
async def _message_loop(self):
try:
await asyncio.wait_for(self.initialize(), LN_P2P_NETWORK_TIMEOUT)
except (OSError, asyncio.TimeoutError, HandshakeFailed) as e:
raise GracefulDisconnect(f'initialize failed: {repr(e)}') from e
if self._sent_init and self._received_init:
self.initialized.set()
async for msg in self.transport.read_messages():
self.process_message(msg)
await asyncio.sleep(.01)
self.ping_if_required()
def on_reply_short_channel_ids_end(self, payload):
self.querying.set()
def close_and_cleanup(self):
try:
if self.transport:
self.transport.close()
except:
pass
self.lnworker.peer_closed(self)
def make_local_config(self, funding_sat: int, push_msat: int, initiator: HTLCOwner) -> LocalConfig:
# key derivation
channel_counter = self.lnworker.get_and_inc_counter_for_channel_keys()
keypair_generator = lambda family: generate_keypair(self.lnworker.ln_keystore, family, channel_counter)
if initiator == LOCAL:
initial_msat = funding_sat * 1000 - push_msat
else:
initial_msat = push_msat
local_config=LocalConfig(
payment_basepoint=keypair_generator(LnKeyFamily.PAYMENT_BASE),
multisig_key=keypair_generator(LnKeyFamily.MULTISIG),
htlc_basepoint=keypair_generator(LnKeyFamily.HTLC_BASE),
delayed_basepoint=keypair_generator(LnKeyFamily.DELAY_BASE),
revocation_basepoint=keypair_generator(LnKeyFamily.REVOCATION_BASE),
to_self_delay=DEFAULT_TO_SELF_DELAY,
dust_limit_sat=546,
max_htlc_value_in_flight_msat=funding_sat * 1000,
max_accepted_htlcs=5,
initial_msat=initial_msat,
reserve_sat=546,
per_commitment_secret_seed=keypair_generator(LnKeyFamily.REVOCATION_ROOT).privkey,
funding_locked_received=False,
was_announced=False,
current_commitment_signature=None,
current_htlc_signatures=b'',
)
return local_config
@log_exceptions
async def channel_establishment_flow(self, password: Optional[str], funding_tx: 'PartialTransaction', funding_sat: int,
push_msat: int, temp_channel_id: bytes) -> Tuple[Channel, 'PartialTransaction']:
await asyncio.wait_for(self.initialized.wait(), LN_P2P_NETWORK_TIMEOUT)
feerate = self.lnworker.current_feerate_per_kw()
local_config = self.make_local_config(funding_sat, push_msat, LOCAL)
# for the first commitment transaction
per_commitment_secret_first = get_per_commitment_secret_from_seed(local_config.per_commitment_secret_seed,
RevocationStore.START_INDEX)
per_commitment_point_first = secret_to_pubkey(int.from_bytes(per_commitment_secret_first, 'big'))
self.send_message(
"open_channel",
temporary_channel_id=temp_channel_id,
chain_hash=constants.net.rev_genesis_bytes(),
funding_satoshis=funding_sat,
push_msat=push_msat,
dust_limit_satoshis=local_config.dust_limit_sat,
feerate_per_kw=feerate,
max_accepted_htlcs=local_config.max_accepted_htlcs,
funding_pubkey=local_config.multisig_key.pubkey,
revocation_basepoint=local_config.revocation_basepoint.pubkey,
htlc_basepoint=local_config.htlc_basepoint.pubkey,
payment_basepoint=local_config.payment_basepoint.pubkey,
delayed_payment_basepoint=local_config.delayed_basepoint.pubkey,
first_per_commitment_point=per_commitment_point_first,
to_self_delay=local_config.to_self_delay,
max_htlc_value_in_flight_msat=local_config.max_htlc_value_in_flight_msat,
channel_flags=0x00, # not willing to announce channel
channel_reserve_satoshis=local_config.reserve_sat,
htlc_minimum_msat=1,
)
payload = await asyncio.wait_for(self.channel_accepted[temp_channel_id].get(), LN_P2P_NETWORK_TIMEOUT)
if payload.get('error'):
raise Exception('Remote Lightning peer reported error: ' + repr(payload.get('error')))
remote_per_commitment_point = payload['first_per_commitment_point']
funding_txn_minimum_depth = int.from_bytes(payload['minimum_depth'], 'big')
if funding_txn_minimum_depth <= 0:
raise Exception(f"minimum depth too low, {funding_txn_minimum_depth}")
if funding_txn_minimum_depth > 30:
raise Exception(f"minimum depth too high, {funding_txn_minimum_depth}")
remote_dust_limit_sat = int.from_bytes(payload['dust_limit_satoshis'], byteorder='big')
remote_reserve_sat = self.validate_remote_reserve(payload["channel_reserve_satoshis"], remote_dust_limit_sat, funding_sat)
if remote_dust_limit_sat > remote_reserve_sat:
raise Exception(f"Remote Lightning peer reports dust_limit_sat > reserve_sat which is a BOLT-02 protocol violation.")
htlc_min = int.from_bytes(payload['htlc_minimum_msat'], 'big')
if htlc_min > MAXIMUM_HTLC_MINIMUM_MSAT_ACCEPTED:
raise Exception(f"Remote Lightning peer reports htlc_minimum_msat={htlc_min} mSAT," +
f" which is above Electrums required maximum limit of that parameter ({MAXIMUM_HTLC_MINIMUM_MSAT_ACCEPTED} mSAT).")
remote_max = int.from_bytes(payload['max_htlc_value_in_flight_msat'], 'big')
if remote_max < MINIMUM_MAX_HTLC_VALUE_IN_FLIGHT_ACCEPTED:
raise Exception(f"Remote Lightning peer reports max_htlc_value_in_flight_msat at only {remote_max} mSAT" +
f" which is below Electrums required minimum ({MINIMUM_MAX_HTLC_VALUE_IN_FLIGHT_ACCEPTED} mSAT).")
max_accepted_htlcs = int.from_bytes(payload["max_accepted_htlcs"], 'big')
if max_accepted_htlcs > 483:
raise Exception("Remote Lightning peer reports max_accepted_htlcs > 483, which is a BOLT-02 protocol violation.")
remote_to_self_delay = int.from_bytes(payload['to_self_delay'], byteorder='big')
if remote_to_self_delay > MAXIMUM_REMOTE_TO_SELF_DELAY_ACCEPTED:
raise Exception(f"Remote Lightning peer reports to_self_delay={remote_to_self_delay}," +
f" which is above Electrums required maximum ({MAXIMUM_REMOTE_TO_SELF_DELAY_ACCEPTED})")
remote_config = RemoteConfig(
payment_basepoint=OnlyPubkeyKeypair(payload['payment_basepoint']),
multisig_key=OnlyPubkeyKeypair(payload["funding_pubkey"]),
htlc_basepoint=OnlyPubkeyKeypair(payload['htlc_basepoint']),
delayed_basepoint=OnlyPubkeyKeypair(payload['delayed_payment_basepoint']),
revocation_basepoint=OnlyPubkeyKeypair(payload['revocation_basepoint']),
to_self_delay=remote_to_self_delay,
dust_limit_sat=remote_dust_limit_sat,
max_htlc_value_in_flight_msat=remote_max,
max_accepted_htlcs=max_accepted_htlcs,
initial_msat=push_msat,
reserve_sat = remote_reserve_sat,
htlc_minimum_msat = htlc_min,
next_per_commitment_point=remote_per_commitment_point,
current_per_commitment_point=None,
)
# replace dummy output in funding tx
redeem_script = funding_output_script(local_config, remote_config)
funding_address = bitcoin.redeem_script_to_address('p2wsh', redeem_script)
funding_output = PartialTxOutput.from_address_and_value(funding_address, funding_sat)
dummy_output = PartialTxOutput.from_address_and_value(ln_dummy_address(), funding_sat)
funding_tx.outputs().remove(dummy_output)
funding_tx.add_outputs([funding_output])
funding_tx.set_rbf(False)
self.lnworker.wallet.sign_transaction(funding_tx, password)
if not funding_tx.is_complete() and not funding_tx.is_segwit():
raise Exception('Funding transaction is not complete')
funding_txid = funding_tx.txid()
assert funding_txid
funding_index = funding_tx.outputs().index(funding_output)
# remote commitment transaction
channel_id, funding_txid_bytes = channel_id_from_funding_tx(funding_txid, funding_index)
outpoint = Outpoint(funding_txid, funding_index)
constraints = ChannelConstraints(capacity=funding_sat, is_initiator=True, funding_txn_minimum_depth=funding_txn_minimum_depth)
chan_dict = self.create_channel_storage(channel_id, outpoint, local_config, remote_config, constraints)
chan = Channel(chan_dict,
sweep_address=self.lnworker.sweep_address,
lnworker=self.lnworker,
initial_feerate=feerate)
sig_64, _ = chan.sign_next_commitment()
self.send_message("funding_created",
temporary_channel_id=temp_channel_id,
funding_txid=funding_txid_bytes,
funding_output_index=funding_index,
signature=sig_64)
payload = await asyncio.wait_for(self.funding_signed[channel_id].get(), LN_P2P_NETWORK_TIMEOUT)
self.logger.info('received funding_signed')
remote_sig = payload['signature']
chan.receive_new_commitment(remote_sig, [])
chan.open_with_first_pcp(remote_per_commitment_point, remote_sig)
return chan, funding_tx
def create_channel_storage(self, channel_id, outpoint, local_config, remote_config, constraints):
chan_dict = {
"node_id": self.pubkey.hex(),
"channel_id": channel_id.hex(),
"short_channel_id": None,
"funding_outpoint": outpoint,
"remote_config": remote_config,
"local_config": local_config,
"constraints": constraints,
"remote_update": None,
"state": channel_states.PREOPENING.name,
"revocation_store": {},
}
return chan_dict
async def on_open_channel(self, payload):
# payload['channel_flags']
if payload['chain_hash'] != constants.net.rev_genesis_bytes():
raise Exception('wrong chain_hash')
funding_sat = int.from_bytes(payload['funding_satoshis'], 'big')
push_msat = int.from_bytes(payload['push_msat'], 'big')
feerate = int.from_bytes(payload['feerate_per_kw'], 'big')
temp_chan_id = payload['temporary_channel_id']
local_config = self.make_local_config(funding_sat, push_msat, REMOTE)
# for the first commitment transaction
per_commitment_secret_first = get_per_commitment_secret_from_seed(local_config.per_commitment_secret_seed,
RevocationStore.START_INDEX)
per_commitment_point_first = secret_to_pubkey(int.from_bytes(per_commitment_secret_first, 'big'))
min_depth = 3
self.send_message('accept_channel',
temporary_channel_id=temp_chan_id,
dust_limit_satoshis=local_config.dust_limit_sat,
max_htlc_value_in_flight_msat=local_config.max_htlc_value_in_flight_msat,
channel_reserve_satoshis=local_config.reserve_sat,
htlc_minimum_msat=1000,
minimum_depth=min_depth,
to_self_delay=local_config.to_self_delay,
max_accepted_htlcs=local_config.max_accepted_htlcs,
funding_pubkey=local_config.multisig_key.pubkey,
revocation_basepoint=local_config.revocation_basepoint.pubkey,
payment_basepoint=local_config.payment_basepoint.pubkey,
delayed_payment_basepoint=local_config.delayed_basepoint.pubkey,
htlc_basepoint=local_config.htlc_basepoint.pubkey,
first_per_commitment_point=per_commitment_point_first,
)
funding_created = await self.funding_created[temp_chan_id].get()
funding_idx = int.from_bytes(funding_created['funding_output_index'], 'big')
funding_txid = bh2u(funding_created['funding_txid'][::-1])
channel_id, funding_txid_bytes = channel_id_from_funding_tx(funding_txid, funding_idx)
remote_balance_sat = funding_sat * 1000 - push_msat
remote_dust_limit_sat = int.from_bytes(payload['dust_limit_satoshis'], byteorder='big') # TODO validate
remote_reserve_sat = self.validate_remote_reserve(payload['channel_reserve_satoshis'], remote_dust_limit_sat, funding_sat)
remote_config = RemoteConfig(
payment_basepoint=OnlyPubkeyKeypair(payload['payment_basepoint']),
multisig_key=OnlyPubkeyKeypair(payload['funding_pubkey']),
htlc_basepoint=OnlyPubkeyKeypair(payload['htlc_basepoint']),
delayed_basepoint=OnlyPubkeyKeypair(payload['delayed_payment_basepoint']),
revocation_basepoint=OnlyPubkeyKeypair(payload['revocation_basepoint']),
to_self_delay=int.from_bytes(payload['to_self_delay'], 'big'),
dust_limit_sat=remote_dust_limit_sat,
max_htlc_value_in_flight_msat=int.from_bytes(payload['max_htlc_value_in_flight_msat'], 'big'), # TODO validate
max_accepted_htlcs=int.from_bytes(payload['max_accepted_htlcs'], 'big'), # TODO validate
initial_msat=remote_balance_sat,
reserve_sat = remote_reserve_sat,
htlc_minimum_msat=int.from_bytes(payload['htlc_minimum_msat'], 'big'), # TODO validate
next_per_commitment_point=payload['first_per_commitment_point'],
current_per_commitment_point=None,
)
constraints = ChannelConstraints(capacity=funding_sat, is_initiator=False, funding_txn_minimum_depth=min_depth)
outpoint = Outpoint(funding_txid, funding_idx)
chan_dict = self.create_channel_storage(channel_id, outpoint, local_config, remote_config, constraints)
chan = Channel(chan_dict,
sweep_address=self.lnworker.sweep_address,
lnworker=self.lnworker,
initial_feerate=feerate)
remote_sig = funding_created['signature']
chan.receive_new_commitment(remote_sig, [])
sig_64, _ = chan.sign_next_commitment()
self.send_message('funding_signed',
channel_id=channel_id,
signature=sig_64,
)
chan.open_with_first_pcp(payload['first_per_commitment_point'], remote_sig)
self.lnworker.save_channel(chan)
self.lnworker.lnwatcher.add_channel(chan.funding_outpoint.to_str(), chan.get_funding_address())
def validate_remote_reserve(self, payload_field: bytes, dust_limit: int, funding_sat: int) -> int:
remote_reserve_sat = int.from_bytes(payload_field, 'big')
if remote_reserve_sat < dust_limit:
raise Exception('protocol violation: reserve < dust_limit')
if remote_reserve_sat > funding_sat/100:
raise Exception(f'reserve too high: {remote_reserve_sat}, funding_sat: {funding_sat}')
return remote_reserve_sat
def on_channel_reestablish(self, payload):
chan_id = payload["channel_id"]
chan = self.channels.get(chan_id)
if not chan:
self.logger.info(f"Received unknown channel_reestablish {bh2u(chan_id)} {payload}")
raise Exception('Unknown channel_reestablish')
self.channel_reestablished[chan_id].put_nowait(payload)
def try_to_get_remote_to_force_close_with_their_latest(self, chan_id):
self.logger.info(f"trying to get remote to force close {bh2u(chan_id)}")
self.send_message(
"channel_reestablish",
channel_id=chan_id,
next_local_commitment_number=0,
next_remote_revocation_number=0)
@log_exceptions
async def reestablish_channel(self, chan: Channel):
await self.initialized.wait()
chan_id = chan.channel_id
if chan.peer_state != peer_states.DISCONNECTED:
self.logger.info('reestablish_channel was called but channel {} already in state {}'
.format(chan_id, chan.get_state()))
return
chan.peer_state = peer_states.REESTABLISHING
self.network.trigger_callback('channel', chan)
# BOLT-02: "A node [...] upon disconnection [...] MUST reverse any uncommitted updates sent by the other side"
chan.hm.discard_unsigned_remote_updates()
# ctns
oldest_unrevoked_local_ctn = chan.get_oldest_unrevoked_ctn(LOCAL)
latest_local_ctn = chan.get_latest_ctn(LOCAL)
next_local_ctn = chan.get_next_ctn(LOCAL)
oldest_unrevoked_remote_ctn = chan.get_oldest_unrevoked_ctn(REMOTE)
latest_remote_ctn = chan.get_latest_ctn(REMOTE)
next_remote_ctn = chan.get_next_ctn(REMOTE)
# send message
dlp_enabled = self.localfeatures & LnLocalFeatures.OPTION_DATA_LOSS_PROTECT_OPT
if dlp_enabled:
if oldest_unrevoked_remote_ctn == 0:
last_rev_secret = 0
else:
last_rev_index = oldest_unrevoked_remote_ctn - 1
last_rev_secret = chan.revocation_store.retrieve_secret(RevocationStore.START_INDEX - last_rev_index)
latest_secret, latest_point = chan.get_secret_and_point(LOCAL, latest_local_ctn)
self.send_message(
"channel_reestablish",
channel_id=chan_id,
next_local_commitment_number=next_local_ctn,
next_remote_revocation_number=oldest_unrevoked_remote_ctn,
your_last_per_commitment_secret=last_rev_secret,
my_current_per_commitment_point=latest_point)
else:
self.send_message(
"channel_reestablish",
channel_id=chan_id,
next_local_commitment_number=next_local_ctn,
next_remote_revocation_number=oldest_unrevoked_remote_ctn)
self.logger.info(f'channel_reestablish: sent channel_reestablish with '
f'(next_local_ctn={next_local_ctn}, '
f'oldest_unrevoked_remote_ctn={oldest_unrevoked_remote_ctn})')
channel_reestablish_msg = await self.channel_reestablished[chan_id].get()
their_next_local_ctn = int.from_bytes(channel_reestablish_msg["next_local_commitment_number"], 'big')
their_oldest_unrevoked_remote_ctn = int.from_bytes(channel_reestablish_msg["next_remote_revocation_number"], 'big')
self.logger.info(f'channel_reestablish: received channel_reestablish with '
f'(their_next_local_ctn={their_next_local_ctn}, '
f'their_oldest_unrevoked_remote_ctn={their_oldest_unrevoked_remote_ctn})')
their_local_pcp = channel_reestablish_msg.get("my_current_per_commitment_point")
their_claim_of_our_last_per_commitment_secret = channel_reestablish_msg.get("your_last_per_commitment_secret")
# sanity checks of received values
if their_next_local_ctn < 0:
raise RemoteMisbehaving(f"channel reestablish: their_next_local_ctn < 0")
if their_oldest_unrevoked_remote_ctn < 0:
raise RemoteMisbehaving(f"channel reestablish: their_oldest_unrevoked_remote_ctn < 0")
# Replay un-acked local updates (including commitment_signed) byte-for-byte.
# If we have sent them a commitment signature that they "lost" (due to disconnect),
# we need to make sure we replay the same local updates, as otherwise they could
# end up with two (or more) signed valid commitment transactions at the same ctn.
# Multiple valid ctxs at the same ctn is a major headache for pre-signing spending txns,
# e.g. for watchtowers, hence we must ensure these ctxs coincide.
# We replay the local updates even if they were not yet committed.
unacked = chan.hm.get_unacked_local_updates()
n_replayed_msgs = 0
for ctn, messages in unacked.items():
if ctn < their_next_local_ctn:
# They claim to have received these messages and the corresponding
# commitment_signed, hence we must not replay them.
continue
for raw_upd_msg in messages:
self.transport.send_bytes(raw_upd_msg)
n_replayed_msgs += 1
self.logger.info(f'channel_reestablish: replayed {n_replayed_msgs} unacked messages')
should_close_we_are_ahead = False
should_close_they_are_ahead = False
# compare remote ctns
if next_remote_ctn != their_next_local_ctn:
if their_next_local_ctn == latest_remote_ctn and chan.hm.is_revack_pending(REMOTE):
# We replayed the local updates (see above), which should have contained a commitment_signed
# (due to is_revack_pending being true), and this should have remedied this situation.
pass
else:
self.logger.warning(f"channel_reestablish: expected remote ctn {next_remote_ctn}, got {their_next_local_ctn}")
if their_next_local_ctn < next_remote_ctn:
should_close_we_are_ahead = True
else:
should_close_they_are_ahead = True
# compare local ctns
if oldest_unrevoked_local_ctn != their_oldest_unrevoked_remote_ctn:
if oldest_unrevoked_local_ctn - 1 == their_oldest_unrevoked_remote_ctn:
# A node:
# if next_remote_revocation_number is equal to the commitment number of the last revoke_and_ack
# the receiving node sent, AND the receiving node hasn't already received a closing_signed:
# MUST re-send the revoke_and_ack.
last_secret, last_point = chan.get_secret_and_point(LOCAL, oldest_unrevoked_local_ctn - 1)
next_secret, next_point = chan.get_secret_and_point(LOCAL, oldest_unrevoked_local_ctn + 1)
self.send_message(
"revoke_and_ack",
channel_id=chan.channel_id,
per_commitment_secret=last_secret,
next_per_commitment_point=next_point)
else:
self.logger.warning(f"channel_reestablish: expected local ctn {oldest_unrevoked_local_ctn}, got {their_oldest_unrevoked_remote_ctn}")
if their_oldest_unrevoked_remote_ctn < oldest_unrevoked_local_ctn:
should_close_we_are_ahead = True
else:
should_close_they_are_ahead = True
# option_data_loss_protect
def are_datalossprotect_fields_valid() -> bool:
if their_local_pcp is None or their_claim_of_our_last_per_commitment_secret is None:
# if DLP was enabled, absence of fields is not OK
return not dlp_enabled
if their_oldest_unrevoked_remote_ctn > 0:
our_pcs, __ = chan.get_secret_and_point(LOCAL, their_oldest_unrevoked_remote_ctn - 1)
else:
assert their_oldest_unrevoked_remote_ctn == 0
our_pcs = bytes(32)
if our_pcs != their_claim_of_our_last_per_commitment_secret:
self.logger.error(f"channel_reestablish: (DLP) local PCS mismatch: {bh2u(our_pcs)} != {bh2u(their_claim_of_our_last_per_commitment_secret)}")
return False
try:
__, our_remote_pcp = chan.get_secret_and_point(REMOTE, their_next_local_ctn - 1)
except RemoteCtnTooFarInFuture:
pass
else:
if our_remote_pcp != their_local_pcp:
self.logger.error(f"channel_reestablish: (DLP) remote PCP mismatch: {bh2u(our_remote_pcp)} != {bh2u(their_local_pcp)}")
return False
return True
if not are_datalossprotect_fields_valid():
raise RemoteMisbehaving("channel_reestablish: data loss protect fields invalid")
else:
if dlp_enabled and should_close_they_are_ahead:
self.logger.warning(f"channel_reestablish: remote is ahead of us! luckily DLP is enabled. remote PCP: {bh2u(their_local_pcp)}")
chan.data_loss_protect_remote_pcp[their_next_local_ctn - 1] = their_local_pcp
self.lnworker.save_channel(chan)
if should_close_they_are_ahead:
self.logger.warning(f"channel_reestablish: remote is ahead of us! trying to get them to force-close.")
self.try_to_get_remote_to_force_close_with_their_latest(chan_id)
return
elif should_close_we_are_ahead:
self.logger.warning(f"channel_reestablish: we are ahead of remote! trying to force-close.")
await self.lnworker.force_close_channel(chan_id)
return
chan.peer_state = peer_states.GOOD
# note: chan.short_channel_id being set implies the funding txn is already at sufficient depth
if their_next_local_ctn == next_local_ctn == 1 and chan.short_channel_id:
self.send_funding_locked(chan)
# checks done
if chan.config[LOCAL].funding_locked_received and chan.short_channel_id:
self.mark_open(chan)
self.network.trigger_callback('channel', chan)
def send_funding_locked(self, chan: Channel):
channel_id = chan.channel_id
per_commitment_secret_index = RevocationStore.START_INDEX - 1
per_commitment_point_second = secret_to_pubkey(int.from_bytes(
get_per_commitment_secret_from_seed(chan.config[LOCAL].per_commitment_secret_seed, per_commitment_secret_index), 'big'))
# note: if funding_locked was not yet received, we might send it multiple times
self.send_message("funding_locked", channel_id=channel_id, next_per_commitment_point=per_commitment_point_second)
if chan.config[LOCAL].funding_locked_received and chan.short_channel_id:
self.mark_open(chan)
def on_funding_locked(self, payload):
channel_id = payload['channel_id']
self.logger.info(f"on_funding_locked. channel: {bh2u(channel_id)}")
chan = self.channels.get(channel_id)
if not chan:
print(self.channels)
raise Exception("Got unknown funding_locked", channel_id)
if not chan.config[LOCAL].funding_locked_received:
our_next_point = chan.config[REMOTE].next_per_commitment_point
their_next_point = payload["next_per_commitment_point"]
chan.config[REMOTE].next_per_commitment_point = their_next_point
chan.config[LOCAL].funding_locked_received = True
self.lnworker.save_channel(chan)
if chan.short_channel_id:
self.mark_open(chan)
def on_network_update(self, chan: Channel, funding_tx_depth: int):
"""
Only called when the channel is OPEN.
Runs on the Network thread.
"""
if not chan.config[LOCAL].was_announced and funding_tx_depth >= 6:
# don't announce our channels
# FIXME should this be a field in chan.local_state maybe?
return
chan.config[LOCAL].was_announced = True
self.lnworker.save_channel(chan)
coro = self.handle_announcements(chan)
asyncio.run_coroutine_threadsafe(coro, self.network.asyncio_loop)
@log_exceptions
async def handle_announcements(self, chan):
h, local_node_sig, local_bitcoin_sig = self.send_announcement_signatures(chan)
announcement_signatures_msg = await self.announcement_signatures[chan.channel_id].get()
remote_node_sig = announcement_signatures_msg["node_signature"]
remote_bitcoin_sig = announcement_signatures_msg["bitcoin_signature"]
if not ecc.verify_signature(chan.config[REMOTE].multisig_key.pubkey, remote_bitcoin_sig, h):
raise Exception("bitcoin_sig invalid in announcement_signatures")
if not ecc.verify_signature(self.pubkey, remote_node_sig, h):
raise Exception("node_sig invalid in announcement_signatures")
node_sigs = [remote_node_sig, local_node_sig]
bitcoin_sigs = [remote_bitcoin_sig, local_bitcoin_sig]
bitcoin_keys = [chan.config[REMOTE].multisig_key.pubkey, chan.config[LOCAL].multisig_key.pubkey]
if self.node_ids[0] > self.node_ids[1]:
node_sigs.reverse()
bitcoin_sigs.reverse()
node_ids = list(reversed(self.node_ids))
bitcoin_keys.reverse()
else:
node_ids = self.node_ids
self.send_message("channel_announcement",
node_signatures_1=node_sigs[0],
node_signatures_2=node_sigs[1],
bitcoin_signature_1=bitcoin_sigs[0],
bitcoin_signature_2=bitcoin_sigs[1],
len=0,
#features not set (defaults to zeros)
chain_hash=constants.net.rev_genesis_bytes(),
short_channel_id=chan.short_channel_id,
node_id_1=node_ids[0],
node_id_2=node_ids[1],
bitcoin_key_1=bitcoin_keys[0],
bitcoin_key_2=bitcoin_keys[1]
)
def mark_open(self, chan: Channel):
assert chan.short_channel_id is not None
scid = chan.short_channel_id
# only allow state transition from "FUNDED" to "OPEN"
old_state = chan.get_state()
if old_state == channel_states.OPEN:
return
if old_state != channel_states.FUNDED:
self.logger.info(f"cannot mark open, current state: {repr(old_state)}")
return
assert chan.config[LOCAL].funding_locked_received
chan.set_state(channel_states.OPEN)
self.network.trigger_callback('channel', chan)
self.add_own_channel(chan)
self.logger.info(f"CHANNEL OPENING COMPLETED for {scid}")
forwarding_enabled = self.network.config.get('lightning_forward_payments', False)
if forwarding_enabled:
# send channel_update of outgoing edge to peer,
# so that channel can be used to to receive payments
self.logger.info(f"sending channel update for outgoing edge of {scid}")
chan_upd = self.get_outgoing_gossip_channel_update_for_chan(chan)
self.transport.send_bytes(chan_upd)
def add_own_channel(self, chan):
# add channel to database
bitcoin_keys = [chan.config[LOCAL].multisig_key.pubkey, chan.config[REMOTE].multisig_key.pubkey]
sorted_node_ids = list(sorted(self.node_ids))
if sorted_node_ids != self.node_ids:
bitcoin_keys.reverse()
# note: we inject a channel announcement, and a channel update (for outgoing direction)
# This is atm needed for
# - finding routes
# - the ChanAnn is needed so that we can anchor to it a future ChanUpd
# that the remote sends, even if the channel was not announced
# (from BOLT-07: "MAY create a channel_update to communicate the channel
# parameters to the final node, even though the channel has not yet been announced")
self.channel_db.add_channel_announcement(
{
"short_channel_id": chan.short_channel_id,
"node_id_1": sorted_node_ids[0],
"node_id_2": sorted_node_ids[1],
'chain_hash': constants.net.rev_genesis_bytes(),
'len': b'\x00\x00',
'features': b'',
'bitcoin_key_1': bitcoin_keys[0],
'bitcoin_key_2': bitcoin_keys[1]
},
trusted=True)
# only inject outgoing direction:
chan_upd_bytes = self.get_outgoing_gossip_channel_update_for_chan(chan)
chan_upd_payload = decode_msg(chan_upd_bytes)[1]
self.channel_db.add_channel_update(chan_upd_payload)
# peer may have sent us a channel update for the incoming direction previously
pending_channel_update = self.orphan_channel_updates.get(chan.short_channel_id)
if pending_channel_update:
chan.remote_update = pending_channel_update['raw']
# add remote update with a fresh timestamp
if chan.remote_update:
now = int(time.time())
remote_update_decoded = decode_msg(chan.remote_update)[1]
remote_update_decoded['timestamp'] = now.to_bytes(4, byteorder="big")
self.channel_db.add_channel_update(remote_update_decoded)
def get_outgoing_gossip_channel_update_for_chan(self, chan: Channel) -> bytes:
if chan._outgoing_channel_update is not None:
return chan._outgoing_channel_update
sorted_node_ids = list(sorted(self.node_ids))
channel_flags = b'\x00' if sorted_node_ids[0] == privkey_to_pubkey(self.privkey) else b'\x01'
now = int(time.time())
htlc_maximum_msat = min(chan.config[REMOTE].max_htlc_value_in_flight_msat, 1000 * chan.constraints.capacity)
chan_upd = encode_msg(
"channel_update",
short_channel_id=chan.short_channel_id,
channel_flags=channel_flags,
message_flags=b'\x01',
cltv_expiry_delta=lnutil.NBLOCK_OUR_CLTV_EXPIRY_DELTA.to_bytes(2, byteorder="big"),
htlc_minimum_msat=chan.config[REMOTE].htlc_minimum_msat.to_bytes(8, byteorder="big"),
htlc_maximum_msat=htlc_maximum_msat.to_bytes(8, byteorder="big"),
fee_base_msat=lnutil.OUR_FEE_BASE_MSAT.to_bytes(4, byteorder="big"),
fee_proportional_millionths=lnutil.OUR_FEE_PROPORTIONAL_MILLIONTHS.to_bytes(4, byteorder="big"),
chain_hash=constants.net.rev_genesis_bytes(),
timestamp=now.to_bytes(4, byteorder="big"),
)
sighash = sha256d(chan_upd[2 + 64:])
sig = ecc.ECPrivkey(self.privkey).sign(sighash, sig_string_from_r_and_s, get_r_and_s_from_sig_string)
message_type, payload = decode_msg(chan_upd)
payload['signature'] = sig
chan_upd = encode_msg(message_type, **payload)
chan._outgoing_channel_update = chan_upd
return chan_upd
def send_announcement_signatures(self, chan: Channel):
bitcoin_keys = [chan.config[REMOTE].multisig_key.pubkey,
chan.config[LOCAL].multisig_key.pubkey]
sorted_node_ids = list(sorted(self.node_ids))
if sorted_node_ids != self.node_ids:
node_ids = sorted_node_ids
bitcoin_keys.reverse()
else:
node_ids = self.node_ids
chan_ann = encode_msg("channel_announcement",
len=0,
#features not set (defaults to zeros)
chain_hash=constants.net.rev_genesis_bytes(),
short_channel_id=chan.short_channel_id,
node_id_1=node_ids[0],
node_id_2=node_ids[1],
bitcoin_key_1=bitcoin_keys[0],
bitcoin_key_2=bitcoin_keys[1]
)
to_hash = chan_ann[256+2:]
h = sha256d(to_hash)
bitcoin_signature = ecc.ECPrivkey(chan.config[LOCAL].multisig_key.privkey).sign(h, sig_string_from_r_and_s, get_r_and_s_from_sig_string)
node_signature = ecc.ECPrivkey(self.privkey).sign(h, sig_string_from_r_and_s, get_r_and_s_from_sig_string)
self.send_message("announcement_signatures",
channel_id=chan.channel_id,
short_channel_id=chan.short_channel_id,
node_signature=node_signature,
bitcoin_signature=bitcoin_signature
)
return h, node_signature, bitcoin_signature
def on_update_fail_htlc(self, payload):
channel_id = payload["channel_id"]
htlc_id = int.from_bytes(payload["id"], "big")
reason = payload["reason"]
chan = self.channels[channel_id]
self.logger.info(f"on_update_fail_htlc. chan {chan.short_channel_id}. htlc_id {htlc_id}")
chan.receive_fail_htlc(htlc_id)
local_ctn = chan.get_latest_ctn(LOCAL)
asyncio.ensure_future(self._on_update_fail_htlc(channel_id, htlc_id, local_ctn, reason))
@log_exceptions
async def _on_update_fail_htlc(self, channel_id, htlc_id, local_ctn, reason):
chan = self.channels[channel_id]
await self.await_local(chan, local_ctn)
payment_hash = chan.get_payment_hash(htlc_id)
self.lnworker.payment_failed(payment_hash, reason)
def maybe_send_commitment(self, chan: Channel):
# REMOTE should revoke first before we can sign a new ctx
if chan.hm.is_revack_pending(REMOTE):
return
# if there are no changes, we will not (and must not) send a new commitment
next_htlcs, latest_htlcs = chan.hm.get_htlcs_in_next_ctx(REMOTE), chan.hm.get_htlcs_in_latest_ctx(REMOTE)
if next_htlcs == latest_htlcs and chan.get_next_feerate(REMOTE) == chan.get_latest_feerate(REMOTE):
return
self.logger.info(f'send_commitment. chan {chan.short_channel_id}. ctn: {chan.get_next_ctn(REMOTE)}. '
f'old number htlcs: {len(latest_htlcs)}, new number htlcs: {len(next_htlcs)}')
sig_64, htlc_sigs = chan.sign_next_commitment()
self.send_message("commitment_signed", channel_id=chan.channel_id, signature=sig_64, num_htlcs=len(htlc_sigs), htlc_signature=b"".join(htlc_sigs))
async def await_remote(self, chan: Channel, ctn: int):
self.maybe_send_commitment(chan)
# TODO review this. I suspect some callers want updates irrevocably committed,
# so comparision should use chan.get_oldest_unrevoked_ctn(REMOTE)
while chan.get_latest_ctn(REMOTE) <= ctn:
await self._remote_changed_events[chan.channel_id].wait()
async def await_local(self, chan: Channel, ctn: int):
self.maybe_send_commitment(chan)
while chan.get_latest_ctn(LOCAL) <= ctn:
await self._local_changed_events[chan.channel_id].wait()
async def pay(self, route: 'LNPaymentRoute', chan: Channel, amount_msat: int,
payment_hash: bytes, min_final_cltv_expiry: int) -> UpdateAddHtlc:
if chan.get_state() != channel_states.OPEN:
raise PaymentFailure('Channel not open')
assert amount_msat > 0, "amount_msat is not greater zero"
await asyncio.wait_for(self.initialized.wait(), LN_P2P_NETWORK_TIMEOUT)
# create onion packet
final_cltv = self.network.get_local_height() + min_final_cltv_expiry
hops_data, amount_msat, cltv = calc_hops_data_for_payment(route, amount_msat, final_cltv)
assert final_cltv <= cltv, (final_cltv, cltv)
secret_key = os.urandom(32)
onion = new_onion_packet([x.node_id for x in route], secret_key, hops_data, associated_data=payment_hash)
# create htlc
htlc = UpdateAddHtlc(amount_msat=amount_msat, payment_hash=payment_hash, cltv_expiry=cltv, timestamp=int(time.time()))
htlc = chan.add_htlc(htlc)
remote_ctn = chan.get_latest_ctn(REMOTE)
chan.onion_keys[htlc.htlc_id] = secret_key
self.logger.info(f"starting payment. len(route)={len(route)}. route: {route}. htlc: {htlc}")
self.send_message("update_add_htlc",
channel_id=chan.channel_id,
id=htlc.htlc_id,
cltv_expiry=htlc.cltv_expiry,
amount_msat=htlc.amount_msat,
payment_hash=htlc.payment_hash,
onion_routing_packet=onion.to_bytes())
await self.await_remote(chan, remote_ctn)
return htlc
def send_revoke_and_ack(self, chan: Channel):
self.logger.info(f'send_revoke_and_ack. chan {chan.short_channel_id}. ctn: {chan.get_oldest_unrevoked_ctn(LOCAL)}')
rev, _ = chan.revoke_current_commitment()
self.lnworker.save_channel(chan)
self._local_changed_events[chan.channel_id].set()
self._local_changed_events[chan.channel_id].clear()
self.send_message("revoke_and_ack",
channel_id=chan.channel_id,
per_commitment_secret=rev.per_commitment_secret,
next_per_commitment_point=rev.next_per_commitment_point)
self.maybe_send_commitment(chan)
def on_commitment_signed(self, payload):
channel_id = payload['channel_id']
chan = self.channels[channel_id]
# make sure there were changes to the ctx, otherwise the remote peer is misbehaving
next_htlcs, latest_htlcs = chan.hm.get_htlcs_in_next_ctx(LOCAL), chan.hm.get_htlcs_in_latest_ctx(LOCAL)
self.logger.info(f'on_commitment_signed. chan {chan.short_channel_id}. ctn: {chan.get_next_ctn(LOCAL)}. '
f'old number htlcs: {len(latest_htlcs)}, new number htlcs: {len(next_htlcs)}')
if (next_htlcs == latest_htlcs
and chan.get_next_feerate(LOCAL) == chan.get_latest_feerate(LOCAL)):
# TODO if feerate changed A->B->A; so there were updates but the value is identical,
# then it might be legal to send a commitment_signature
# see https://github.com/lightningnetwork/lightning-rfc/pull/618
raise RemoteMisbehaving('received commitment_signed without pending changes')
# REMOTE should wait until we have revoked
if chan.hm.is_revack_pending(LOCAL):
raise RemoteMisbehaving('received commitment_signed before we revoked previous ctx')
data = payload["htlc_signature"]
htlc_sigs = [data[i:i+64] for i in range(0, len(data), 64)]
chan.receive_new_commitment(payload["signature"], htlc_sigs)
self.send_revoke_and_ack(chan)
def on_update_fulfill_htlc(self, update_fulfill_htlc_msg):
chan = self.channels[update_fulfill_htlc_msg["channel_id"]]
preimage = update_fulfill_htlc_msg["payment_preimage"]
payment_hash = sha256(preimage)
htlc_id = int.from_bytes(update_fulfill_htlc_msg["id"], "big")
self.logger.info(f"on_update_fulfill_htlc. chan {chan.short_channel_id}. htlc_id {htlc_id}")
chan.receive_htlc_settle(preimage, htlc_id)
self.lnworker.save_preimage(payment_hash, preimage)
local_ctn = chan.get_latest_ctn(LOCAL)
asyncio.ensure_future(self._on_update_fulfill_htlc(chan, local_ctn, payment_hash))
@log_exceptions
async def _on_update_fulfill_htlc(self, chan, local_ctn, payment_hash):
await self.await_local(chan, local_ctn)
self.lnworker.payment_sent(payment_hash)
def on_update_fail_malformed_htlc(self, payload):
self.logger.info(f"on_update_fail_malformed_htlc. error {payload['data'].decode('ascii')}")
def on_update_add_htlc(self, payload):
payment_hash = payload["payment_hash"]
channel_id = payload['channel_id']
chan = self.channels[channel_id]
htlc_id = int.from_bytes(payload["id"], 'big')
self.logger.info(f"on_update_add_htlc. chan {chan.short_channel_id}. htlc_id {htlc_id}")
cltv_expiry = int.from_bytes(payload["cltv_expiry"], 'big')
amount_msat_htlc = int.from_bytes(payload["amount_msat"], 'big')
onion_packet = OnionPacket.from_bytes(payload["onion_routing_packet"])
processed_onion = process_onion_packet(onion_packet, associated_data=payment_hash, our_onion_private_key=self.privkey)
if chan.get_state() != channel_states.OPEN:
raise RemoteMisbehaving(f"received update_add_htlc while chan.get_state() != OPEN. state was {chan.get_state()}")
if cltv_expiry >= 500_000_000:
asyncio.ensure_future(self.lnworker.force_close_channel(channel_id))
raise RemoteMisbehaving(f"received update_add_htlc with cltv_expiry >= 500_000_000. value was {cltv_expiry}")
# add htlc
htlc = UpdateAddHtlc(amount_msat=amount_msat_htlc,
payment_hash=payment_hash,
cltv_expiry=cltv_expiry,
timestamp=int(time.time()),
htlc_id=htlc_id)
htlc = chan.receive_htlc(htlc)
local_ctn = chan.get_latest_ctn(LOCAL)
remote_ctn = chan.get_latest_ctn(REMOTE)
if processed_onion.are_we_final:
asyncio.ensure_future(self._maybe_fulfill_htlc(chan=chan,
htlc=htlc,
local_ctn=local_ctn,
remote_ctn=remote_ctn,
onion_packet=onion_packet,
processed_onion=processed_onion))
else:
asyncio.ensure_future(self._maybe_forward_htlc(chan=chan,
htlc=htlc,
local_ctn=local_ctn,
remote_ctn=remote_ctn,
onion_packet=onion_packet,
processed_onion=processed_onion))
@log_exceptions
async def _maybe_forward_htlc(self, chan: Channel, htlc: UpdateAddHtlc, *, local_ctn: int, remote_ctn: int,
onion_packet: OnionPacket, processed_onion: ProcessedOnionPacket):
await self.await_local(chan, local_ctn)
await self.await_remote(chan, remote_ctn)
# Forward HTLC
# FIXME: this is not robust to us going offline before payment is fulfilled
# FIXME: there are critical safety checks MISSING here
forwarding_enabled = self.network.config.get('lightning_forward_payments', False)
if not forwarding_enabled:
self.logger.info(f"forwarding is disabled. failing htlc.")
reason = OnionRoutingFailureMessage(code=OnionFailureCode.PERMANENT_CHANNEL_FAILURE, data=b'')
await self.fail_htlc(chan, htlc.htlc_id, onion_packet, reason)
return
dph = processed_onion.hop_data.per_hop
next_chan = self.lnworker.get_channel_by_short_id(dph.short_channel_id)
next_chan_scid = dph.short_channel_id
next_peer = self.lnworker.peers[next_chan.node_id]
local_height = self.network.get_local_height()
if next_chan is None:
self.logger.info(f"cannot forward htlc. cannot find next_chan {next_chan_scid}")
reason = OnionRoutingFailureMessage(code=OnionFailureCode.UNKNOWN_NEXT_PEER, data=b'')
await self.fail_htlc(chan, htlc.htlc_id, onion_packet, reason)
return
outgoing_chan_upd = self.get_outgoing_gossip_channel_update_for_chan(next_chan)[2:]
outgoing_chan_upd_len = len(outgoing_chan_upd).to_bytes(2, byteorder="big")
if next_chan.get_state() != channel_states.OPEN:
self.logger.info(f"cannot forward htlc. next_chan not OPEN: {next_chan_scid} in state {next_chan.get_state()}")
reason = OnionRoutingFailureMessage(code=OnionFailureCode.TEMPORARY_CHANNEL_FAILURE,
data=outgoing_chan_upd_len+outgoing_chan_upd)
await self.fail_htlc(chan, htlc.htlc_id, onion_packet, reason)
return
next_cltv_expiry = int.from_bytes(dph.outgoing_cltv_value, 'big')
if htlc.cltv_expiry - next_cltv_expiry < NBLOCK_OUR_CLTV_EXPIRY_DELTA:
reason = OnionRoutingFailureMessage(code=OnionFailureCode.INCORRECT_CLTV_EXPIRY,
data=(htlc.cltv_expiry.to_bytes(4, byteorder="big")
+ outgoing_chan_upd_len + outgoing_chan_upd))
await self.fail_htlc(chan, htlc.htlc_id, onion_packet, reason)
return
if htlc.cltv_expiry - lnutil.NBLOCK_DEADLINE_BEFORE_EXPIRY_FOR_RECEIVED_HTLCS <= local_height \
or next_cltv_expiry <= local_height:
reason = OnionRoutingFailureMessage(code=OnionFailureCode.EXPIRY_TOO_SOON,
data=outgoing_chan_upd_len+outgoing_chan_upd)
await self.fail_htlc(chan, htlc.htlc_id, onion_packet, reason)
return
if max(htlc.cltv_expiry, next_cltv_expiry) > local_height + lnutil.NBLOCK_CLTV_EXPIRY_TOO_FAR_INTO_FUTURE:
reason = OnionRoutingFailureMessage(code=OnionFailureCode.EXPIRY_TOO_FAR, data=b'')
await self.fail_htlc(chan, htlc.htlc_id, onion_packet, reason)
return
next_amount_msat_htlc = int.from_bytes(dph.amt_to_forward, 'big')
forwarding_fees = fee_for_edge_msat(forwarded_amount_msat=next_amount_msat_htlc,
fee_base_msat=lnutil.OUR_FEE_BASE_MSAT,
fee_proportional_millionths=lnutil.OUR_FEE_PROPORTIONAL_MILLIONTHS)
if htlc.amount_msat - next_amount_msat_htlc < forwarding_fees:
reason = OnionRoutingFailureMessage(code=OnionFailureCode.FEE_INSUFFICIENT,
data=(next_amount_msat_htlc.to_bytes(8, byteorder="big")
+ outgoing_chan_upd_len + outgoing_chan_upd))
await self.fail_htlc(chan, htlc.htlc_id, onion_packet, reason)
return
self.logger.info(f'forwarding htlc to {next_chan.node_id}')
next_htlc = UpdateAddHtlc(amount_msat=next_amount_msat_htlc, payment_hash=htlc.payment_hash, cltv_expiry=next_cltv_expiry, timestamp=int(time.time()))
next_htlc = next_chan.add_htlc(next_htlc)
next_remote_ctn = next_chan.get_latest_ctn(REMOTE)
next_peer.send_message(
"update_add_htlc",
channel_id=next_chan.channel_id,
id=next_htlc.htlc_id,
cltv_expiry=dph.outgoing_cltv_value,
amount_msat=dph.amt_to_forward,
payment_hash=next_htlc.payment_hash,
onion_routing_packet=processed_onion.next_packet.to_bytes()
)
await next_peer.await_remote(next_chan, next_remote_ctn)
success, preimage, reason = await self.lnworker.await_payment(next_htlc.payment_hash)
if success:
await self._fulfill_htlc(chan, htlc.htlc_id, preimage)
self.logger.info("htlc forwarded successfully")
else:
# TODO: test this
self.logger.info(f"forwarded htlc has failed, {reason}")
await self.fail_htlc(chan, htlc.htlc_id, onion_packet, reason)
@log_exceptions
async def _maybe_fulfill_htlc(self, chan: Channel, htlc: UpdateAddHtlc, *, local_ctn: int, remote_ctn: int,
onion_packet: OnionPacket, processed_onion: ProcessedOnionPacket):
await self.await_local(chan, local_ctn)
await self.await_remote(chan, remote_ctn)
try:
info = self.lnworker.get_payment_info(htlc.payment_hash)
preimage = self.lnworker.get_preimage(htlc.payment_hash)
except UnknownPaymentHash:
reason = OnionRoutingFailureMessage(code=OnionFailureCode.INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS, data=b'')
await self.fail_htlc(chan, htlc.htlc_id, onion_packet, reason)
return
expected_received_msat = int(info.amount * 1000) if info.amount is not None else None
if expected_received_msat is not None and \
not (expected_received_msat <= htlc.amount_msat <= 2 * expected_received_msat):
reason = OnionRoutingFailureMessage(code=OnionFailureCode.INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS, data=b'')
await self.fail_htlc(chan, htlc.htlc_id, onion_packet, reason)
return
local_height = self.network.get_local_height()
if local_height + MIN_FINAL_CLTV_EXPIRY_ACCEPTED > htlc.cltv_expiry:
reason = OnionRoutingFailureMessage(code=OnionFailureCode.FINAL_EXPIRY_TOO_SOON, data=b'')
await self.fail_htlc(chan, htlc.htlc_id, onion_packet, reason)
return
cltv_from_onion = int.from_bytes(processed_onion.hop_data.per_hop.outgoing_cltv_value, byteorder="big")
if cltv_from_onion != htlc.cltv_expiry:
reason = OnionRoutingFailureMessage(code=OnionFailureCode.FINAL_INCORRECT_CLTV_EXPIRY,
data=htlc.cltv_expiry.to_bytes(4, byteorder="big"))
await self.fail_htlc(chan, htlc.htlc_id, onion_packet, reason)
return
amount_from_onion = int.from_bytes(processed_onion.hop_data.per_hop.amt_to_forward, byteorder="big")
if amount_from_onion > htlc.amount_msat:
reason = OnionRoutingFailureMessage(code=OnionFailureCode.FINAL_INCORRECT_HTLC_AMOUNT,
data=htlc.amount_msat.to_bytes(8, byteorder="big"))
await self.fail_htlc(chan, htlc.htlc_id, onion_packet, reason)
return
#self.network.trigger_callback('htlc_added', htlc, invoice, RECEIVED)
await asyncio.sleep(self.network.config.lightning_settle_delay)
await self._fulfill_htlc(chan, htlc.htlc_id, preimage)
async def _fulfill_htlc(self, chan: Channel, htlc_id: int, preimage: bytes):
self.logger.info(f"_fulfill_htlc. chan {chan.short_channel_id}. htlc_id {htlc_id}")
chan.settle_htlc(preimage, htlc_id)
payment_hash = sha256(preimage)
self.lnworker.payment_received(payment_hash)
remote_ctn = chan.get_latest_ctn(REMOTE)
self.send_message("update_fulfill_htlc",
channel_id=chan.channel_id,
id=htlc_id,
payment_preimage=preimage)
await self.await_remote(chan, remote_ctn)
async def fail_htlc(self, chan: Channel, htlc_id: int, onion_packet: OnionPacket,
reason: OnionRoutingFailureMessage):
self.logger.info(f"fail_htlc. chan {chan.short_channel_id}. htlc_id {htlc_id}. reason: {reason}")
chan.fail_htlc(htlc_id)
remote_ctn = chan.get_latest_ctn(REMOTE)
error_packet = construct_onion_error(reason, onion_packet, our_onion_private_key=self.privkey)
self.send_message("update_fail_htlc",
channel_id=chan.channel_id,
id=htlc_id,
len=len(error_packet),
reason=error_packet)
await self.await_remote(chan, remote_ctn)
def on_revoke_and_ack(self, payload):
channel_id = payload["channel_id"]
chan = self.channels[channel_id]
self.logger.info(f'on_revoke_and_ack. chan {chan.short_channel_id}. ctn: {chan.get_oldest_unrevoked_ctn(REMOTE)}')
rev = RevokeAndAck(payload["per_commitment_secret"], payload["next_per_commitment_point"])
chan.receive_revocation(rev)
self._remote_changed_events[chan.channel_id].set()
self._remote_changed_events[chan.channel_id].clear()
self.lnworker.save_channel(chan)
self.maybe_send_commitment(chan)
def on_update_fee(self, payload):
channel_id = payload["channel_id"]
feerate =int.from_bytes(payload["feerate_per_kw"], "big")
chan = self.channels[channel_id]
chan.update_fee(feerate, False)
async def bitcoin_fee_update(self, chan: Channel):
"""
called when our fee estimates change
"""
if not chan.constraints.is_initiator:
# TODO force close if initiator does not update_fee enough
return
feerate_per_kw = self.lnworker.current_feerate_per_kw()
chan_fee = chan.get_next_feerate(REMOTE)
self.logger.info(f"current pending feerate {chan_fee}")
self.logger.info(f"new feerate {feerate_per_kw}")
if feerate_per_kw < chan_fee / 2:
self.logger.info("FEES HAVE FALLEN")
elif feerate_per_kw > chan_fee * 2:
self.logger.info("FEES HAVE RISEN")
else:
return
chan.update_fee(feerate_per_kw, True)
remote_ctn = chan.get_latest_ctn(REMOTE)
self.send_message("update_fee",
channel_id=chan.channel_id,
feerate_per_kw=feerate_per_kw)
await self.await_remote(chan, remote_ctn)
def on_closing_signed(self, payload):
chan_id = payload["channel_id"]
if chan_id not in self.closing_signed: raise Exception("Got unknown closing_signed")
self.closing_signed[chan_id].put_nowait(payload)
@log_exceptions
async def close_channel(self, chan_id: bytes):
chan = self.channels[chan_id]
self.shutdown_received[chan_id] = asyncio.Future()
self.send_shutdown(chan)
payload = await self.shutdown_received[chan_id]
txid = await self._shutdown(chan, payload, True)
self.logger.info(f'Channel closed {txid}')
return txid
@log_exceptions
async def on_shutdown(self, payload):
# length of scripts allowed in BOLT-02
if int.from_bytes(payload['len'], 'big') not in (3+20+2, 2+20+1, 2+20, 2+32):
raise Exception('scriptpubkey length in received shutdown message invalid: ' + str(payload['len']))
chan_id = payload['channel_id']
if chan_id in self.shutdown_received:
self.shutdown_received[chan_id].set_result(payload)
else:
chan = self.channels[chan_id]
self.send_shutdown(chan)
txid = await self._shutdown(chan, payload, False)
self.logger.info(f'Channel closed by remote peer {txid}')
def send_shutdown(self, chan: Channel):
scriptpubkey = bfh(bitcoin.address_to_script(chan.sweep_address))
self.send_message('shutdown', channel_id=chan.channel_id, len=len(scriptpubkey), scriptpubkey=scriptpubkey)
@log_exceptions
async def _shutdown(self, chan: Channel, payload, is_local):
# set state so that we stop accepting HTLCs
chan.set_state(channel_states.CLOSING)
# wait until no HTLCs remain in either commitment transaction
while len(chan.hm.htlcs(LOCAL)) + len(chan.hm.htlcs(REMOTE)) > 0:
self.logger.info('waiting for htlcs to settle...')
await asyncio.sleep(1)
our_fee = chan.pending_local_fee()
scriptpubkey = bfh(bitcoin.address_to_script(chan.sweep_address))
# negotiate fee
while True:
our_sig, closing_tx = chan.make_closing_tx(scriptpubkey, payload['scriptpubkey'], fee_sat=our_fee)
self.send_message('closing_signed', channel_id=chan.channel_id, fee_satoshis=our_fee, signature=our_sig)
cs_payload = await asyncio.wait_for(self.closing_signed[chan.channel_id].get(), LN_P2P_NETWORK_TIMEOUT)
their_fee = int.from_bytes(cs_payload['fee_satoshis'], 'big')
their_sig = cs_payload['signature']
if our_fee == their_fee:
break
# TODO: negotiate better
our_fee = their_fee
# add signatures
closing_tx.add_signature_to_txin(txin_idx=0,
signing_pubkey=chan.config[LOCAL].multisig_key.pubkey.hex(),
sig=bh2u(der_sig_from_sig_string(our_sig) + b'\x01'))
closing_tx.add_signature_to_txin(txin_idx=0,
signing_pubkey=chan.config[REMOTE].multisig_key.pubkey.hex(),
sig=bh2u(der_sig_from_sig_string(their_sig) + b'\x01'))
# broadcast
await self.network.broadcast_transaction(closing_tx)
return closing_tx.txid()