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# 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 threading
from typing import NamedTuple, Iterable, TYPE_CHECKING
import os
from collections import defaultdict
import asyncio
from enum import IntEnum, auto
import jsonrpclib
from .util import PrintError, bh2u, bfh, log_exceptions, ignore_exceptions
from .lnutil import EncumberedTransaction
from . import wallet
from .storage import WalletStorage
from .address_synchronizer import AddressSynchronizer, TX_HEIGHT_LOCAL, TX_HEIGHT_UNCONF_PARENT, TX_HEIGHT_UNCONFIRMED
if TYPE_CHECKING:
from .network import Network
class TxMinedDepth(IntEnum):
""" IntEnum because we call min() in get_deepest_tx_mined_depth_for_txids """
DEEP = auto()
SHALLOW = auto()
MEMPOOL = auto()
FREE = auto()
class LNWatcher(PrintError):
# TODO if verifier gets an incorrect merkle proof, that tx will never verify!!
# similarly, what if server ignores request for merkle proof?
# maybe we should disconnect from server in these cases
verbosity_filter = 'W'
def __init__(self, network: 'Network'):
self.network = network
self.config = network.config
path = os.path.join(network.config.path, "watcher_db")
storage = WalletStorage(path)
self.addr_sync = AddressSynchronizer(storage)
self.addr_sync.diagnostic_name = lambda: 'LnWatcherAS'
self.addr_sync.start_network(network)
self.lock = threading.RLock()
self.watched_addresses = set()
self.channel_info = storage.get('channel_info', {}) # access with 'lock'
# [funding_outpoint_str][prev_txid] -> set of EncumberedTransaction
# prev_txid is the txid of a tx that is watched for confirmations
# access with 'lock'
self.sweepstore = defaultdict(lambda: defaultdict(set))
for funding_outpoint, ctxs in storage.get('sweepstore', {}).items():
for txid, set_of_txns in ctxs.items():
for e_tx in set_of_txns:
e_tx2 = EncumberedTransaction.from_json(e_tx)
self.sweepstore[funding_outpoint][txid].add(e_tx2)
self.network.register_callback(self.on_network_update,
['network_updated', 'blockchain_updated', 'verified', 'wallet_updated'])
# remote watchtower
watchtower_url = self.config.get('watchtower_url')
self.watchtower = jsonrpclib.Server(watchtower_url) if watchtower_url else None
self.watchtower_queue = asyncio.Queue()
def with_watchtower(func):
def wrapper(self, *args, **kwargs):
if self.watchtower:
self.watchtower_queue.put_nowait((func.__name__, args, kwargs))
return func(self, *args, **kwargs)
return wrapper
@ignore_exceptions
@log_exceptions
async def watchtower_task(self):
self.print_error('watchtower task started')
while True:
name, args, kwargs = await self.watchtower_queue.get()
if self.watchtower is None:
continue
func = getattr(self.watchtower, name)
try:
r = func(*args, **kwargs)
self.print_error("watchtower answer", r)
except:
self.print_error('could not reach watchtower, will retry in 5s', name, args)
await asyncio.sleep(5)
await self.watchtower_queue.put((name, args, kwargs))
def write_to_disk(self):
# FIXME: json => every update takes linear instead of constant disk write
with self.lock:
storage = self.addr_sync.storage
storage.put('channel_info', self.channel_info)
# self.sweepstore
sweepstore = {}
for funding_outpoint, ctxs in self.sweepstore.items():
sweepstore[funding_outpoint] = {}
for prev_txid, set_of_txns in ctxs.items():
sweepstore[funding_outpoint][prev_txid] = [e_tx.to_json() for e_tx in set_of_txns]
storage.put('sweepstore', sweepstore)
storage.write()
@with_watchtower
def watch_channel(self, address, outpoint):
self.watch_address(address)
with self.lock:
if address not in self.channel_info:
self.channel_info[address] = outpoint
self.write_to_disk()
@log_exceptions
async def on_network_update(self, event, *args):
if event in ('verified', 'wallet_updated'):
wallet = args[0]
if wallet != self.addr_sync:
return
if not self.addr_sync.synchronizer:
self.print_error("synchronizer not set yet")
return
if not self.addr_sync.synchronizer.is_up_to_date():
return
with self.lock:
channel_info_items = list(self.channel_info.items())
for address, outpoint in channel_info_items:
await self.check_onchain_situation(outpoint)
def watch_address(self, addr):
with self.lock:
self.watched_addresses.add(addr)
self.addr_sync.add_address(addr)
async def check_onchain_situation(self, funding_outpoint):
txid, index = funding_outpoint.split(':')
ctx_candidate_txid = self.addr_sync.spent_outpoints[txid].get(int(index))
is_spent = ctx_candidate_txid is not None
self.network.trigger_callback('channel_txo', funding_outpoint, is_spent)
if not is_spent:
return
ctx_candidate = self.addr_sync.transactions.get(ctx_candidate_txid)
if ctx_candidate is None:
return
#self.print_error("funding outpoint {} is spent by {}"
# .format(funding_outpoint, ctx_candidate_txid))
conf = self.addr_sync.get_tx_height(ctx_candidate_txid).conf
# only care about confirmed and verified ctxs. TODO is this necessary?
if conf == 0:
return
keep_watching_this = await self.inspect_tx_candidate(funding_outpoint, ctx_candidate)
if not keep_watching_this:
self.stop_and_delete(funding_outpoint)
def stop_and_delete(self, funding_outpoint):
# TODO delete channel from watcher_db
pass
async def inspect_tx_candidate(self, funding_outpoint, prev_tx):
"""Returns True iff found any not-deeply-spent outputs that we could
potentially sweep at some point."""
# make sure we are subscribed to all outputs of tx
not_yet_watching = False
for o in prev_tx.outputs():
if o.address not in self.watched_addresses:
self.watch_address(o.address)
not_yet_watching = True
if not_yet_watching:
return True
# get all possible responses we have
prev_txid = prev_tx.txid()
with self.lock:
encumbered_sweep_txns = self.sweepstore[funding_outpoint][prev_txid]
if len(encumbered_sweep_txns) == 0:
if self.get_tx_mined_depth(prev_txid) == TxMinedDepth.DEEP:
return False
# check if any response applies
keep_watching_this = False
local_height = self.network.get_local_height()
for e_tx in list(encumbered_sweep_txns):
conflicts = self.addr_sync.get_conflicting_transactions(e_tx.tx.txid(), e_tx.tx, include_self=True)
conflict_mined_depth = self.get_deepest_tx_mined_depth_for_txids(conflicts)
if conflict_mined_depth != TxMinedDepth.DEEP:
keep_watching_this = True
if conflict_mined_depth == TxMinedDepth.FREE:
tx_height = self.addr_sync.get_tx_height(prev_txid).height
if tx_height == TX_HEIGHT_LOCAL:
continue
num_conf = local_height - tx_height + 1
broadcast = True
if e_tx.cltv_expiry:
if local_height > e_tx.cltv_expiry:
self.print_error('CLTV ({} > {}) fulfilled'.format(local_height, e_tx.cltv_expiry))
else:
self.print_error('waiting for {}: CLTV ({} > {}), funding outpoint {} and tx {}'
.format(e_tx.name, local_height, e_tx.cltv_expiry, funding_outpoint[:8], prev_tx.txid()[:8]))
broadcast = False
if e_tx.csv_delay:
if num_conf < e_tx.csv_delay:
self.print_error('waiting for {}: CSV ({} >= {}), funding outpoint {} and tx {}'
.format(e_tx.name, num_conf, e_tx.csv_delay, funding_outpoint[:8], prev_tx.txid()[:8]))
broadcast = False
if broadcast:
if not await self.broadcast_or_log(e_tx):
self.print_error(f'encumbered tx: {str(e_tx)}, prev_txid: {prev_txid}')
else:
# not mined or in mempool
keep_watching_this |= await self.inspect_tx_candidate(funding_outpoint, e_tx.tx)
return keep_watching_this
async def broadcast_or_log(self, e_tx):
try:
txid = await self.network.broadcast_transaction(e_tx.tx)
except Exception as e:
self.print_error(f'broadcast: {e_tx.name}: failure: {repr(e)}')
else:
self.print_error(f'broadcast: {e_tx.name}: success. txid: {txid}')
@with_watchtower
def add_sweep_tx(self, funding_outpoint: str, prev_txid: str, sweeptx):
encumbered_sweeptx = EncumberedTransaction.from_json(sweeptx)
with self.lock:
self.sweepstore[funding_outpoint][prev_txid].add(encumbered_sweeptx)
self.write_to_disk()
def get_tx_mined_depth(self, txid: str):
if not txid:
return TxMinedStatus.FREE
tx_mined_depth = self.addr_sync.get_tx_height(txid)
height, conf = tx_mined_depth.height, tx_mined_depth.conf
if conf > 100:
return TxMinedDepth.DEEP
elif conf > 0:
return TxMinedDepth.SHALLOW
elif height in (TX_HEIGHT_UNCONFIRMED, TX_HEIGHT_UNCONF_PARENT):
return TxMinedDepth.MEMPOOL
elif height == TX_HEIGHT_LOCAL:
return TxMinedDepth.FREE
elif height > 0 and conf == 0:
# unverified but claimed to be mined
return TxMinedDepth.MEMPOOL
else:
raise NotImplementedError()
def get_deepest_tx_mined_depth_for_txids(self, set_of_txids: Iterable[str]):
if not set_of_txids:
return TxMinedDepth.FREE
# note: using "min" as lower status values are deeper
return min(map(self.get_tx_mined_depth, set_of_txids))