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       tlnwatcher.py - electrum - Electrum Bitcoin wallet
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       ---
       tlnwatcher.py (18166B)
       ---
            1 # Copyright (C) 2018 The Electrum developers
            2 # Distributed under the MIT software license, see the accompanying
            3 # file LICENCE or http://www.opensource.org/licenses/mit-license.php
            4 
            5 from typing import NamedTuple, Iterable, TYPE_CHECKING
            6 import os
            7 import asyncio
            8 from enum import IntEnum, auto
            9 from typing import NamedTuple, Dict
           10 
           11 from . import util
           12 from .sql_db import SqlDB, sql
           13 from .wallet_db import WalletDB
           14 from .util import bh2u, bfh, log_exceptions, ignore_exceptions, TxMinedInfo, random_shuffled_copy
           15 from .address_synchronizer import AddressSynchronizer, TX_HEIGHT_LOCAL, TX_HEIGHT_UNCONF_PARENT, TX_HEIGHT_UNCONFIRMED
           16 from .transaction import Transaction, TxOutpoint
           17 
           18 if TYPE_CHECKING:
           19     from .network import Network
           20     from .lnsweep import SweepInfo
           21     from .lnworker import LNWallet
           22 
           23 class ListenerItem(NamedTuple):
           24     # this is triggered when the lnwatcher is all done with the outpoint used as index in LNWatcher.tx_progress
           25     all_done : asyncio.Event
           26     # txs we broadcast are put on this queue so that the test can wait for them to get mined
           27     tx_queue : asyncio.Queue
           28 
           29 class TxMinedDepth(IntEnum):
           30     """ IntEnum because we call min() in get_deepest_tx_mined_depth_for_txids """
           31     DEEP = auto()
           32     SHALLOW = auto()
           33     MEMPOOL = auto()
           34     FREE = auto()
           35 
           36 
           37 create_sweep_txs="""
           38 CREATE TABLE IF NOT EXISTS sweep_txs (
           39 funding_outpoint VARCHAR(34) NOT NULL,
           40 ctn INTEGER NOT NULL,
           41 prevout VARCHAR(34),
           42 tx VARCHAR
           43 )"""
           44 
           45 create_channel_info="""
           46 CREATE TABLE IF NOT EXISTS channel_info (
           47 outpoint VARCHAR(34) NOT NULL,
           48 address VARCHAR(32),
           49 PRIMARY KEY(outpoint)
           50 )"""
           51 
           52 
           53 class SweepStore(SqlDB):
           54 
           55     def __init__(self, path, network):
           56         super().__init__(network.asyncio_loop, path)
           57 
           58     def create_database(self):
           59         c = self.conn.cursor()
           60         c.execute(create_channel_info)
           61         c.execute(create_sweep_txs)
           62         self.conn.commit()
           63 
           64     @sql
           65     def get_sweep_tx(self, funding_outpoint, prevout):
           66         c = self.conn.cursor()
           67         c.execute("SELECT tx FROM sweep_txs WHERE funding_outpoint=? AND prevout=?", (funding_outpoint, prevout))
           68         return [Transaction(bh2u(r[0])) for r in c.fetchall()]
           69 
           70     @sql
           71     def list_sweep_tx(self):
           72         c = self.conn.cursor()
           73         c.execute("SELECT funding_outpoint FROM sweep_txs")
           74         return set([r[0] for r in c.fetchall()])
           75 
           76     @sql
           77     def add_sweep_tx(self, funding_outpoint, ctn, prevout, raw_tx):
           78         c = self.conn.cursor()
           79         assert Transaction(raw_tx).is_complete()
           80         c.execute("""INSERT INTO sweep_txs (funding_outpoint, ctn, prevout, tx) VALUES (?,?,?,?)""", (funding_outpoint, ctn, prevout, bfh(raw_tx)))
           81         self.conn.commit()
           82 
           83     @sql
           84     def get_num_tx(self, funding_outpoint):
           85         c = self.conn.cursor()
           86         c.execute("SELECT count(*) FROM sweep_txs WHERE funding_outpoint=?", (funding_outpoint,))
           87         return int(c.fetchone()[0])
           88 
           89     @sql
           90     def get_ctn(self, outpoint, addr):
           91         if not self._has_channel(outpoint):
           92             self._add_channel(outpoint, addr)
           93         c = self.conn.cursor()
           94         c.execute("SELECT max(ctn) FROM sweep_txs WHERE funding_outpoint=?", (outpoint,))
           95         return int(c.fetchone()[0] or 0)
           96 
           97     @sql
           98     def remove_sweep_tx(self, funding_outpoint):
           99         c = self.conn.cursor()
          100         c.execute("DELETE FROM sweep_txs WHERE funding_outpoint=?", (funding_outpoint,))
          101         self.conn.commit()
          102 
          103     def _add_channel(self, outpoint, address):
          104         c = self.conn.cursor()
          105         c.execute("INSERT INTO channel_info (address, outpoint) VALUES (?,?)", (address, outpoint))
          106         self.conn.commit()
          107 
          108     @sql
          109     def remove_channel(self, outpoint):
          110         c = self.conn.cursor()
          111         c.execute("DELETE FROM channel_info WHERE outpoint=?", (outpoint,))
          112         self.conn.commit()
          113 
          114     def _has_channel(self, outpoint):
          115         c = self.conn.cursor()
          116         c.execute("SELECT * FROM channel_info WHERE outpoint=?", (outpoint,))
          117         r = c.fetchone()
          118         return r is not None
          119 
          120     @sql
          121     def get_address(self, outpoint):
          122         c = self.conn.cursor()
          123         c.execute("SELECT address FROM channel_info WHERE outpoint=?", (outpoint,))
          124         r = c.fetchone()
          125         return r[0] if r else None
          126 
          127     @sql
          128     def list_channels(self):
          129         c = self.conn.cursor()
          130         c.execute("SELECT outpoint, address FROM channel_info")
          131         return [(r[0], r[1]) for r in c.fetchall()]
          132 
          133 
          134 
          135 class LNWatcher(AddressSynchronizer):
          136     LOGGING_SHORTCUT = 'W'
          137 
          138     def __init__(self, network: 'Network'):
          139         AddressSynchronizer.__init__(self, WalletDB({}, manual_upgrades=False))
          140         self.config = network.config
          141         self.callbacks = {} # address -> lambda: coroutine
          142         self.network = network
          143         util.register_callback(
          144             self.on_network_update,
          145             ['network_updated', 'blockchain_updated', 'verified', 'wallet_updated', 'fee'])
          146 
          147         # status gets populated when we run
          148         self.channel_status = {}
          149 
          150     async def stop(self):
          151         await super().stop()
          152         util.unregister_callback(self.on_network_update)
          153 
          154     def get_channel_status(self, outpoint):
          155         return self.channel_status.get(outpoint, 'unknown')
          156 
          157     def add_channel(self, outpoint: str, address: str) -> None:
          158         assert isinstance(outpoint, str)
          159         assert isinstance(address, str)
          160         cb = lambda: self.check_onchain_situation(address, outpoint)
          161         self.add_callback(address, cb)
          162 
          163     async def unwatch_channel(self, address, funding_outpoint):
          164         self.logger.info(f'unwatching {funding_outpoint}')
          165         self.remove_callback(address)
          166 
          167     def remove_callback(self, address):
          168         self.callbacks.pop(address, None)
          169 
          170     def add_callback(self, address, callback):
          171         self.add_address(address)
          172         self.callbacks[address] = callback
          173 
          174     @log_exceptions
          175     async def on_network_update(self, event, *args):
          176         if event in ('verified', 'wallet_updated'):
          177             if args[0] != self:
          178                 return
          179         if not self.synchronizer:
          180             self.logger.info("synchronizer not set yet")
          181             return
          182         for address, callback in list(self.callbacks.items()):
          183             await callback()
          184 
          185     async def check_onchain_situation(self, address, funding_outpoint):
          186         # early return if address has not been added yet
          187         if not self.is_mine(address):
          188             return
          189         spenders = self.inspect_tx_candidate(funding_outpoint, 0)
          190         # inspect_tx_candidate might have added new addresses, in which case we return ealy
          191         if not self.is_up_to_date():
          192             return
          193         funding_txid = funding_outpoint.split(':')[0]
          194         funding_height = self.get_tx_height(funding_txid)
          195         closing_txid = spenders.get(funding_outpoint)
          196         closing_height = self.get_tx_height(closing_txid)
          197         if closing_txid:
          198             closing_tx = self.db.get_transaction(closing_txid)
          199             if closing_tx:
          200                 keep_watching = await self.do_breach_remedy(funding_outpoint, closing_tx, spenders)
          201             else:
          202                 self.logger.info(f"channel {funding_outpoint} closed by {closing_txid}. still waiting for tx itself...")
          203                 keep_watching = True
          204         else:
          205             keep_watching = True
          206         await self.update_channel_state(
          207             funding_outpoint=funding_outpoint,
          208             funding_txid=funding_txid,
          209             funding_height=funding_height,
          210             closing_txid=closing_txid,
          211             closing_height=closing_height,
          212             keep_watching=keep_watching)
          213         if not keep_watching:
          214             await self.unwatch_channel(address, funding_outpoint)
          215 
          216     async def do_breach_remedy(self, funding_outpoint, closing_tx, spenders) -> bool:
          217         raise NotImplementedError()  # implemented by subclasses
          218 
          219     async def update_channel_state(self, *, funding_outpoint: str, funding_txid: str,
          220                                    funding_height: TxMinedInfo, closing_txid: str,
          221                                    closing_height: TxMinedInfo, keep_watching: bool) -> None:
          222         raise NotImplementedError()  # implemented by subclasses
          223 
          224     def inspect_tx_candidate(self, outpoint, n):
          225         prev_txid, index = outpoint.split(':')
          226         txid = self.db.get_spent_outpoint(prev_txid, int(index))
          227         result = {outpoint:txid}
          228         if txid is None:
          229             self.channel_status[outpoint] = 'open'
          230             return result
          231         if n == 0 and not self.is_deeply_mined(txid):
          232             self.channel_status[outpoint] = 'closed (%d)' % self.get_tx_height(txid).conf
          233         else:
          234             self.channel_status[outpoint] = 'closed (deep)'
          235         tx = self.db.get_transaction(txid)
          236         for i, o in enumerate(tx.outputs()):
          237             if not self.is_mine(o.address):
          238                 self.add_address(o.address)
          239             elif n < 2:
          240                 r = self.inspect_tx_candidate(txid+':%d'%i, n+1)
          241                 result.update(r)
          242         return result
          243 
          244     def get_tx_mined_depth(self, txid: str):
          245         if not txid:
          246             return TxMinedDepth.FREE
          247         tx_mined_depth = self.get_tx_height(txid)
          248         height, conf = tx_mined_depth.height, tx_mined_depth.conf
          249         if conf > 100:
          250             return TxMinedDepth.DEEP
          251         elif conf > 0:
          252             return TxMinedDepth.SHALLOW
          253         elif height in (TX_HEIGHT_UNCONFIRMED, TX_HEIGHT_UNCONF_PARENT):
          254             return TxMinedDepth.MEMPOOL
          255         elif height == TX_HEIGHT_LOCAL:
          256             return TxMinedDepth.FREE
          257         elif height > 0 and conf == 0:
          258             # unverified but claimed to be mined
          259             return TxMinedDepth.MEMPOOL
          260         else:
          261             raise NotImplementedError()
          262 
          263     def is_deeply_mined(self, txid):
          264         return self.get_tx_mined_depth(txid) == TxMinedDepth.DEEP
          265 
          266 
          267 class WatchTower(LNWatcher):
          268 
          269     LOGGING_SHORTCUT = 'W'
          270 
          271     def __init__(self, network):
          272         LNWatcher.__init__(self, network)
          273         self.network = network
          274         self.sweepstore = SweepStore(os.path.join(self.network.config.path, "watchtower_db"), network)
          275         # this maps funding_outpoints to ListenerItems, which have an event for when the watcher is done,
          276         # and a queue for seeing which txs are being published
          277         self.tx_progress = {} # type: Dict[str, ListenerItem]
          278 
          279     def diagnostic_name(self):
          280         return "local_tower"
          281 
          282     async def start_watching(self):
          283         # I need to watch the addresses from sweepstore
          284         lst = await self.sweepstore.list_channels()
          285         for outpoint, address in random_shuffled_copy(lst):
          286             self.add_channel(outpoint, address)
          287 
          288     async def do_breach_remedy(self, funding_outpoint, closing_tx, spenders):
          289         keep_watching = False
          290         for prevout, spender in spenders.items():
          291             if spender is not None:
          292                 keep_watching |= not self.is_deeply_mined(spender)
          293                 continue
          294             sweep_txns = await self.sweepstore.get_sweep_tx(funding_outpoint, prevout)
          295             for tx in sweep_txns:
          296                 await self.broadcast_or_log(funding_outpoint, tx)
          297                 keep_watching = True
          298         return keep_watching
          299 
          300     async def broadcast_or_log(self, funding_outpoint: str, tx: Transaction):
          301         height = self.get_tx_height(tx.txid()).height
          302         if height != TX_HEIGHT_LOCAL:
          303             return
          304         try:
          305             txid = await self.network.broadcast_transaction(tx)
          306         except Exception as e:
          307             self.logger.info(f'broadcast failure: txid={tx.txid()}, funding_outpoint={funding_outpoint}: {repr(e)}')
          308         else:
          309             self.logger.info(f'broadcast success: txid={tx.txid()}, funding_outpoint={funding_outpoint}')
          310             if funding_outpoint in self.tx_progress:
          311                 await self.tx_progress[funding_outpoint].tx_queue.put(tx)
          312             return txid
          313 
          314     def get_ctn(self, outpoint, addr):
          315         async def f():
          316             return await self.sweepstore.get_ctn(outpoint, addr)
          317         return self.network.run_from_another_thread(f())
          318 
          319     def get_num_tx(self, outpoint):
          320         async def f():
          321             return await self.sweepstore.get_num_tx(outpoint)
          322         return self.network.run_from_another_thread(f())
          323 
          324     def list_sweep_tx(self):
          325         async def f():
          326             return await self.sweepstore.list_sweep_tx()
          327         return self.network.run_from_another_thread(f())
          328 
          329     def list_channels(self):
          330         async def f():
          331             return await self.sweepstore.list_channels()
          332         return self.network.run_from_another_thread(f())
          333 
          334     async def unwatch_channel(self, address, funding_outpoint):
          335         await super().unwatch_channel(address, funding_outpoint)
          336         await self.sweepstore.remove_sweep_tx(funding_outpoint)
          337         await self.sweepstore.remove_channel(funding_outpoint)
          338         if funding_outpoint in self.tx_progress:
          339             self.tx_progress[funding_outpoint].all_done.set()
          340 
          341     async def update_channel_state(self, *args, **kwargs):
          342         pass
          343 
          344 
          345 
          346 
          347 class LNWalletWatcher(LNWatcher):
          348 
          349     def __init__(self, lnworker: 'LNWallet', network: 'Network'):
          350         self.network = network
          351         self.lnworker = lnworker
          352         LNWatcher.__init__(self, network)
          353 
          354     def diagnostic_name(self):
          355         return f"{self.lnworker.wallet.diagnostic_name()}-LNW"
          356 
          357     @ignore_exceptions
          358     @log_exceptions
          359     async def update_channel_state(self, *, funding_outpoint: str, funding_txid: str,
          360                                    funding_height: TxMinedInfo, closing_txid: str,
          361                                    closing_height: TxMinedInfo, keep_watching: bool) -> None:
          362         chan = self.lnworker.channel_by_txo(funding_outpoint)
          363         if not chan:
          364             return
          365         chan.update_onchain_state(funding_txid=funding_txid,
          366                                   funding_height=funding_height,
          367                                   closing_txid=closing_txid,
          368                                   closing_height=closing_height,
          369                                   keep_watching=keep_watching)
          370         await self.lnworker.on_channel_update(chan)
          371 
          372     async def do_breach_remedy(self, funding_outpoint, closing_tx, spenders):
          373         chan = self.lnworker.channel_by_txo(funding_outpoint)
          374         if not chan:
          375             return False
          376         # detect who closed and set sweep_info
          377         sweep_info_dict = chan.sweep_ctx(closing_tx)
          378         keep_watching = False if sweep_info_dict else not self.is_deeply_mined(closing_tx.txid())
          379         self.logger.info(f'(chan {chan.get_id_for_log()}) sweep_info_dict {[x.name for x in sweep_info_dict.values()]}')
          380         # create and broadcast transaction
          381         for prevout, sweep_info in sweep_info_dict.items():
          382             name = sweep_info.name + ' ' + chan.get_id_for_log()
          383             spender_txid = spenders.get(prevout)
          384             if spender_txid is not None:
          385                 spender_tx = self.db.get_transaction(spender_txid)
          386                 if not spender_tx:
          387                     keep_watching = True
          388                     continue
          389                 e_htlc_tx = chan.maybe_sweep_revoked_htlc(closing_tx, spender_tx)
          390                 if e_htlc_tx:
          391                     spender2 = spenders.get(spender_txid+':0')
          392                     if spender2:
          393                         self.logger.info(f'(chan {chan.get_id_for_log()}) htlc is already spent {name}: {prevout}')
          394                         keep_watching |= not self.is_deeply_mined(spender2)
          395                     else:
          396                         self.logger.info(f'(chan {chan.get_id_for_log()}) trying to redeem htlc {name}: {prevout}')
          397                         await self.try_redeem(spender_txid+':0', e_htlc_tx, name)
          398                         keep_watching = True
          399                 else:
          400                     self.logger.info(f'(chan {chan.get_id_for_log()}) outpoint already spent {name}: {prevout}')
          401                     keep_watching |= not self.is_deeply_mined(spender_txid)
          402                     txin_idx = spender_tx.get_input_idx_that_spent_prevout(TxOutpoint.from_str(prevout))
          403                     assert txin_idx is not None
          404                     spender_txin = spender_tx.inputs()[txin_idx]
          405                     chan.extract_preimage_from_htlc_txin(spender_txin)
          406             else:
          407                 self.logger.info(f'(chan {chan.get_id_for_log()}) trying to redeem {name}: {prevout}')
          408                 await self.try_redeem(prevout, sweep_info, name)
          409                 keep_watching = True
          410         return keep_watching
          411 
          412     @log_exceptions
          413     async def try_redeem(self, prevout: str, sweep_info: 'SweepInfo', name: str) -> None:
          414         prev_txid, prev_index = prevout.split(':')
          415         broadcast = True
          416         if sweep_info.cltv_expiry:
          417             local_height = self.network.get_local_height()
          418             remaining = sweep_info.cltv_expiry - local_height
          419             if remaining > 0:
          420                 self.logger.info('waiting for {}: CLTV ({} > {}), prevout {}'
          421                                  .format(name, local_height, sweep_info.cltv_expiry, prevout))
          422                 broadcast = False
          423         if sweep_info.csv_delay:
          424             prev_height = self.get_tx_height(prev_txid)
          425             remaining = sweep_info.csv_delay - prev_height.conf
          426             if remaining > 0:
          427                 self.logger.info('waiting for {}: CSV ({} >= {}), prevout: {}'
          428                                  .format(name, prev_height.conf, sweep_info.csv_delay, prevout))
          429                 broadcast = False
          430         tx = sweep_info.gen_tx()
          431         if tx is None:
          432             self.logger.info(f'{name} could not claim output: {prevout}, dust')
          433         self.lnworker.wallet.set_label(tx.txid(), name)
          434         if broadcast:
          435             await self.network.try_broadcasting(tx, name)
          436         else:
          437             # it's OK to add local transaction, the fee will be recomputed
          438             try:
          439                 tx_was_added = self.lnworker.wallet.add_future_tx(tx, remaining)
          440             except Exception as e:
          441                 self.logger.info(f'could not add future tx: {name}. prevout: {prevout} {str(e)}')
          442                 tx_was_added = False
          443             if tx_was_added:
          444                 self.logger.info(f'added future tx: {name}. prevout: {prevout}')
          445                 util.trigger_callback('wallet_updated', self.lnworker.wallet)