import asyncio import os from decimal import Decimal import random import time from typing import Optional, Sequence import dns.resolver import dns.exception from . import constants from .bitcoin import sha256, COIN from .util import bh2u, bfh, PrintError, InvoiceError, resolve_dns_srv from .lnbase import Peer, privkey_to_pubkey, aiosafe from .lnaddr import lnencode, LnAddr, lndecode from .ecc import der_sig_from_sig_string from .lnhtlc import HTLCStateMachine from .lnutil import Outpoint, calc_short_channel_id, LNPeerAddr, get_compressed_pubkey_from_bech32 from .lnwatcher import LNChanCloseHandler from .i18n import _ NUM_PEERS_TARGET = 4 PEER_RETRY_INTERVAL = 600 # seconds FALLBACK_NODE_LIST = ( LNPeerAddr('ecdsa.net', 9735, bfh('038370f0e7a03eded3e1d41dc081084a87f0afa1c5b22090b4f3abb391eb15d8ff')), ) class LNWorker(PrintError): def __init__(self, wallet, network): self.wallet = wallet self.network = network self.channel_db = self.network.channel_db pk = wallet.storage.get('lightning_privkey') if pk is None: pk = bh2u(os.urandom(32)) wallet.storage.put('lightning_privkey', pk) wallet.storage.write() self.privkey = bfh(pk) self.pubkey = privkey_to_pubkey(self.privkey) self.config = network.config self.peers = {} self.channels = {x.channel_id: x for x in map(HTLCStateMachine, wallet.storage.get("channels", []))} self.invoices = wallet.storage.get('lightning_invoices', {}) for chan_id, chan in self.channels.items(): self.network.lnwatcher.watch_channel(chan, self.on_channel_utxos) self._last_tried_peer = {} # LNPeerAddr -> unix timestamp # TODO peers that we have channels with should also be added now # but we don't store their IP/port yet.. also what if it changes? # need to listen for node_announcements and save the new IP/port self._add_peers_from_config() # wait until we see confirmations self.network.register_callback(self.on_network_update, ['updated', 'verified', 'fee_histogram']) # thread safe self.on_network_update('updated') # shortcut (don't block) if funding tx locked and verified self.network.futures.append(asyncio.run_coroutine_threadsafe(self.main_loop(), asyncio.get_event_loop())) def _add_peers_from_config(self): peer_list = self.config.get('lightning_peers', []) for host, port, pubkey in peer_list: self.add_peer(host, int(port), bfh(pubkey)) def suggest_peer(self): for node_id, peer in self.peers.items(): if len(peer.channels) > 0: continue if not(peer.initialized.done()): continue return node_id def channels_for_peer(self, node_id): assert type(node_id) is bytes return {x: y for (x, y) in self.channels.items() if y.node_id == node_id} def add_peer(self, host, port, node_id): port = int(port) peer = Peer(self, host, port, node_id, request_initial_sync=self.config.get("request_initial_sync", True)) self.network.futures.append(asyncio.run_coroutine_threadsafe(peer.main_loop(), asyncio.get_event_loop())) self.peers[node_id] = peer self.network.trigger_callback('ln_status') def save_channel(self, openchannel): assert type(openchannel) is HTLCStateMachine self.channels[openchannel.channel_id] = openchannel if openchannel.remote_state.next_per_commitment_point == openchannel.remote_state.current_per_commitment_point: raise Exception("Tried to save channel with next_point == current_point, this should not happen") dumped = [x.serialize() for x in self.channels.values()] self.wallet.storage.put("channels", dumped) self.wallet.storage.write() self.network.trigger_callback('channel', openchannel) def save_short_chan_id(self, chan): """ Checks if the Funding TX has been mined. If it has save the short channel ID to disk and return the new OpenChannel. If the Funding TX has not been mined, return None """ assert chan.state in ["OPEN", "OPENING"] peer = self.peers[chan.node_id] conf = self.wallet.get_tx_height(chan.funding_outpoint.txid)[1] if conf >= chan.constraints.funding_txn_minimum_depth: block_height, tx_pos = self.wallet.get_txpos(chan.funding_outpoint.txid) if tx_pos == -1: self.print_error('funding tx is not yet SPV verified.. but there are ' 'already enough confirmations (currently {})'.format(conf)) return False chan.short_channel_id = calc_short_channel_id(block_height, tx_pos, chan.funding_outpoint.output_index) self.save_channel(chan) return True return False def on_channel_utxos(self, chan, utxos): outpoints = [Outpoint(x["tx_hash"], x["tx_pos"]) for x in utxos] if chan.funding_outpoint not in outpoints: chan.state = "CLOSED" # FIXME is this properly GC-ed? (or too soon?) LNChanCloseHandler(self.network, self.wallet, chan) elif chan.state == 'DISCONNECTED': if chan.node_id not in self.peers: self.print_error("received channel_utxos for channel which does not have peer (errored?)") return peer = self.peers[chan.node_id] coro = peer.reestablish_channel(chan) asyncio.run_coroutine_threadsafe(coro, self.network.asyncio_loop) self.network.trigger_callback('channel', chan) def on_network_update(self, event, *args): """ called from network thread """ # Race discovered in save_channel (assertion failing): # since short_channel_id could be changed while saving. # Mitigated by posting to loop: async def network_jobs(): for chan in self.channels.values(): if chan.state == "OPENING": res = self.save_short_chan_id(chan) if not res: self.print_error("network update but funding tx is still not at sufficient depth") continue # this results in the channel being marked OPEN peer = self.peers[chan.node_id] peer.funding_locked(chan) elif chan.state == "OPEN": peer = self.peers.get(chan.node_id) if peer is None: self.print_error("peer not found for {}".format(bh2u(chan.node_id))) return if event == 'fee_histogram': peer.on_bitcoin_fee_update(chan) conf = self.wallet.get_tx_height(chan.funding_outpoint.txid)[1] peer.on_network_update(chan, conf) asyncio.run_coroutine_threadsafe(network_jobs(), self.network.asyncio_loop).result() async def _open_channel_coroutine(self, node_id, local_amount_sat, push_sat, password): peer = self.peers[node_id] openingchannel = await peer.channel_establishment_flow(self.wallet, self.config, password, local_amount_sat + push_sat, push_sat * 1000, temp_channel_id=os.urandom(32)) if not openingchannel: self.print_error("Channel_establishment_flow returned None") return self.save_channel(openingchannel) self.network.lnwatcher.watch_channel(openingchannel, self.on_channel_utxos) self.on_channels_updated() def on_channels_updated(self): self.network.trigger_callback('channels') def open_channel(self, node_id, local_amt_sat, push_amt_sat, pw): coro = self._open_channel_coroutine(node_id, local_amt_sat, push_amt_sat, None if pw == "" else pw) return asyncio.run_coroutine_threadsafe(coro, self.network.asyncio_loop) def pay(self, invoice, amount_sat=None): addr = lndecode(invoice, expected_hrp=constants.net.SEGWIT_HRP) payment_hash = addr.paymenthash invoice_pubkey = addr.pubkey.serialize() amount_sat = (addr.amount * COIN) if addr.amount else amount_sat if amount_sat is None: raise InvoiceError(_("Missing amount")) amount_msat = int(amount_sat * 1000) path = self.network.path_finder.find_path_for_payment(self.pubkey, invoice_pubkey, amount_msat) if path is None: raise Exception("No path found") node_id, short_channel_id = path[0] peer = self.peers[node_id] for chan in self.channels.values(): if chan.short_channel_id == short_channel_id: break else: raise Exception("ChannelDB returned path with short_channel_id that is not in channel list") coro = peer.pay(path, chan, amount_msat, payment_hash, invoice_pubkey, addr.min_final_cltv_expiry) return asyncio.run_coroutine_threadsafe(coro, self.network.asyncio_loop) def add_invoice(self, amount_sat, message): payment_preimage = os.urandom(32) RHASH = sha256(payment_preimage) amount_btc = amount_sat/Decimal(COIN) if amount_sat else None pay_req = lnencode(LnAddr(RHASH, amount_btc, tags=[('d', message)]), self.privkey) self.invoices[bh2u(payment_preimage)] = pay_req self.wallet.storage.put('lightning_invoices', self.invoices) self.wallet.storage.write() return pay_req def delete_invoice(self, payreq_key): try: del self.invoices[payreq_key] except KeyError: return self.wallet.storage.put('lightning_invoices', self.invoices) self.wallet.storage.write() def list_channels(self): return [str(x) for x in self.channels] def close_channel(self, chan_id): chan = self.channels[chan_id] # local_commitment always gives back the next expected local_commitment, # but in this case, we want the current one. So substract one ctn number old_local_state = chan.local_state chan.local_state=chan.local_state._replace(ctn=chan.local_state.ctn - 1) tx = chan.pending_local_commitment chan.local_state = old_local_state tx.sign({bh2u(chan.local_config.multisig_key.pubkey): (chan.local_config.multisig_key.privkey, True)}) remote_sig = chan.local_state.current_commitment_signature remote_sig = der_sig_from_sig_string(remote_sig) + b"\x01" none_idx = tx._inputs[0]["signatures"].index(None) tx.add_signature_to_txin(0, none_idx, bh2u(remote_sig)) assert tx.is_complete() return self.network.broadcast_transaction(tx) def _get_next_peers_to_try(self) -> Sequence[LNPeerAddr]: now = time.time() recent_peers = self.channel_db.get_recent_peers() # maintenance for last tried times for peer in list(self._last_tried_peer): if now >= self._last_tried_peer[peer] + PEER_RETRY_INTERVAL: del self._last_tried_peer[peer] # first try from recent peers for peer in recent_peers: if peer in self.peers: continue if peer in self._last_tried_peer: # due to maintenance above, this means we tried recently continue return [peer] # try random peer from graph all_nodes = self.channel_db.nodes if all_nodes: self.print_error('trying to get ln peers from channel db') node_ids = list(all_nodes) max_tries = min(200, len(all_nodes)) for i in range(max_tries): node_id = random.choice(node_ids) node = all_nodes.get(node_id) if node is None: continue addresses = node.addresses if not addresses: continue host, port = addresses[0] peer = LNPeerAddr(host, port, node_id) if peer in self._last_tried_peer: continue self.print_error('taking random ln peer from our channel db') return [peer] # TODO remove this. For some reason the dns seeds seem to ignore the realm byte # and only return mainnet nodes. so for the time being dns seeding is disabled: if constants.net in (constants.BitcoinTestnet, ): return [random.choice(FALLBACK_NODE_LIST)] else: return [] # try peers from dns seed. # return several peers to reduce the number of dns queries. if not constants.net.LN_DNS_SEEDS: return [] dns_seed = random.choice(constants.net.LN_DNS_SEEDS) self.print_error('asking dns seed "{}" for ln peers'.format(dns_seed)) try: # note: this might block for several seconds # this will include bech32-encoded-pubkeys and ports srv_answers = resolve_dns_srv('r{}.{}'.format( constants.net.LN_REALM_BYTE, dns_seed)) except dns.exception.DNSException as e: return [] random.shuffle(srv_answers) num_peers = 2 * NUM_PEERS_TARGET srv_answers = srv_answers[:num_peers] # we now have pubkeys and ports but host is still needed peers = [] for srv_ans in srv_answers: try: # note: this might block for several seconds answers = dns.resolver.query(srv_ans['host']) except dns.exception.DNSException: continue else: ln_host = str(answers[0]) port = int(srv_ans['port']) bech32_pubkey = srv_ans['host'].split('.')[0] pubkey = get_compressed_pubkey_from_bech32(bech32_pubkey) peers.append(LNPeerAddr(ln_host, port, pubkey)) self.print_error('got {} ln peers from dns seed'.format(len(peers))) return peers @aiosafe async def main_loop(self): while True: await asyncio.sleep(1) for k, peer in list(self.peers.items()): if peer.exception: self.print_error("removing peer", peer.host) self.peers.pop(k) if len(self.peers) >= NUM_PEERS_TARGET: continue peers = self._get_next_peers_to_try() for peer in peers: self._last_tried_peer[peer] = time.time() self.print_error("trying node", peer) self.add_peer(peer.host, peer.port, peer.pubkey)