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# -*- coding: utf-8 -*-
#
# Electrum - lightweight Bitcoin client
# Copyright (C) 2018 The Electrum developers
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
from datetime import datetime
import time
import random
import queue
import os
import json
import threading
import concurrent
from collections import defaultdict
from typing import Sequence, List, Tuple, Optional, Dict, NamedTuple, TYPE_CHECKING, Set
import binascii
import base64
from sqlalchemy import Column, ForeignKey, Integer, String, Boolean
from sqlalchemy.orm.query import Query
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.sql import not_, or_
from .sql_db import SqlDB, sql
from . import constants
from .util import bh2u, profiler, get_headers_dir, bfh, is_ip_address, list_enabled_bits, print_msg
from .logging import Logger
from .storage import JsonDB
from .lnverifier import LNChannelVerifier, verify_sig_for_channel_update
from .crypto import sha256d
from . import ecc
from .lnutil import (LN_GLOBAL_FEATURES_KNOWN_SET, LNPeerAddr, NUM_MAX_EDGES_IN_PAYMENT_PATH,
NotFoundChanAnnouncementForUpdate)
from .lnmsg import encode_msg
if TYPE_CHECKING:
from .lnchannel import Channel
from .network import Network
class UnknownEvenFeatureBits(Exception): pass
class NoChannelPolicy(Exception):
def __init__(self, short_channel_id: bytes):
super().__init__(f'cannot find channel policy for short_channel_id: {bh2u(short_channel_id)}')
def validate_features(features : int):
enabled_features = list_enabled_bits(features)
for fbit in enabled_features:
if (1 << fbit) not in LN_GLOBAL_FEATURES_KNOWN_SET and fbit % 2 == 0:
raise UnknownEvenFeatureBits()
Base = declarative_base()
FLAG_DISABLE = 1 << 1
FLAG_DIRECTION = 1 << 0
class ChannelInfo(Base):
__tablename__ = 'channel_info'
short_channel_id = Column(String(64), primary_key=True)
node1_id = Column(String(66), ForeignKey('node_info.node_id'), nullable=False)
node2_id = Column(String(66), ForeignKey('node_info.node_id'), nullable=False)
capacity_sat = Column(Integer)
msg_payload_hex = Column(String(1024), nullable=False)
trusted = Column(Boolean, nullable=False)
@staticmethod
def from_msg(payload):
features = int.from_bytes(payload['features'], 'big')
validate_features(features)
channel_id = payload['short_channel_id'].hex()
node_id_1 = payload['node_id_1'].hex()
node_id_2 = payload['node_id_2'].hex()
assert list(sorted([node_id_1, node_id_2])) == [node_id_1, node_id_2]
msg_payload_hex = encode_msg('channel_announcement', **payload).hex()
capacity_sat = None
return ChannelInfo(short_channel_id = channel_id, node1_id = node_id_1,
node2_id = node_id_2, capacity_sat = capacity_sat, msg_payload_hex = msg_payload_hex,
trusted = False)
@property
def msg_payload(self):
return bytes.fromhex(self.msg_payload_hex)
class Policy(Base):
__tablename__ = 'policy'
start_node = Column(String(66), ForeignKey('node_info.node_id'), primary_key=True)
short_channel_id = Column(String(64), ForeignKey('channel_info.short_channel_id'), primary_key=True)
cltv_expiry_delta = Column(Integer, nullable=False)
htlc_minimum_msat = Column(Integer, nullable=False)
htlc_maximum_msat = Column(Integer)
fee_base_msat = Column(Integer, nullable=False)
fee_proportional_millionths = Column(Integer, nullable=False)
channel_flags = Column(Integer, nullable=False)
timestamp = Column(Integer, nullable=False)
@staticmethod
def from_msg(payload, start_node, short_channel_id):
cltv_expiry_delta = payload['cltv_expiry_delta']
htlc_minimum_msat = payload['htlc_minimum_msat']
fee_base_msat = payload['fee_base_msat']
fee_proportional_millionths = payload['fee_proportional_millionths']
channel_flags = payload['channel_flags']
timestamp = payload['timestamp']
htlc_maximum_msat = payload.get('htlc_maximum_msat') # optional
cltv_expiry_delta = int.from_bytes(cltv_expiry_delta, "big")
htlc_minimum_msat = int.from_bytes(htlc_minimum_msat, "big")
htlc_maximum_msat = int.from_bytes(htlc_maximum_msat, "big") if htlc_maximum_msat else None
fee_base_msat = int.from_bytes(fee_base_msat, "big")
fee_proportional_millionths = int.from_bytes(fee_proportional_millionths, "big")
channel_flags = int.from_bytes(channel_flags, "big")
timestamp = int.from_bytes(timestamp, "big")
return Policy(start_node=start_node,
short_channel_id=short_channel_id,
cltv_expiry_delta=cltv_expiry_delta,
htlc_minimum_msat=htlc_minimum_msat,
fee_base_msat=fee_base_msat,
fee_proportional_millionths=fee_proportional_millionths,
channel_flags=channel_flags,
timestamp=timestamp,
htlc_maximum_msat=htlc_maximum_msat)
def is_disabled(self):
return self.channel_flags & FLAG_DISABLE
class NodeInfo(Base):
__tablename__ = 'node_info'
node_id = Column(String(66), primary_key=True, sqlite_on_conflict_primary_key='REPLACE')
features = Column(Integer, nullable=False)
timestamp = Column(Integer, nullable=False)
alias = Column(String(64), nullable=False)
@staticmethod
def from_msg(payload):
node_id = payload['node_id'].hex()
features = int.from_bytes(payload['features'], "big")
validate_features(features)
addresses = NodeInfo.parse_addresses_field(payload['addresses'])
alias = payload['alias'].rstrip(b'\x00').hex()
timestamp = int.from_bytes(payload['timestamp'], "big")
return NodeInfo(node_id=node_id, features=features, timestamp=timestamp, alias=alias), [
Address(host=host, port=port, node_id=node_id, last_connected_date=None) for host, port in addresses]
@staticmethod
def parse_addresses_field(addresses_field):
buf = addresses_field
def read(n):
nonlocal buf
data, buf = buf[0:n], buf[n:]
return data
addresses = []
while buf:
atype = ord(read(1))
if atype == 0:
pass
elif atype == 1: # IPv4
ipv4_addr = '.'.join(map(lambda x: '%d' % x, read(4)))
port = int.from_bytes(read(2), 'big')
if is_ip_address(ipv4_addr) and port != 0:
addresses.append((ipv4_addr, port))
elif atype == 2: # IPv6
ipv6_addr = b':'.join([binascii.hexlify(read(2)) for i in range(8)])
ipv6_addr = ipv6_addr.decode('ascii')
port = int.from_bytes(read(2), 'big')
if is_ip_address(ipv6_addr) and port != 0:
addresses.append((ipv6_addr, port))
elif atype == 3: # onion v2
host = base64.b32encode(read(10)) + b'.onion'
host = host.decode('ascii').lower()
port = int.from_bytes(read(2), 'big')
addresses.append((host, port))
elif atype == 4: # onion v3
host = base64.b32encode(read(35)) + b'.onion'
host = host.decode('ascii').lower()
port = int.from_bytes(read(2), 'big')
addresses.append((host, port))
else:
# unknown address type
# we don't know how long it is -> have to escape
# if there are other addresses we could have parsed later, they are lost.
break
return addresses
class Address(Base):
__tablename__ = 'address'
node_id = Column(String(66), ForeignKey('node_info.node_id'), primary_key=True)
host = Column(String(256), primary_key=True)
port = Column(Integer, primary_key=True)
last_connected_date = Column(Integer(), nullable=True)
class ChannelDB(SqlDB):
NUM_MAX_RECENT_PEERS = 20
def __init__(self, network: 'Network'):
path = os.path.join(get_headers_dir(network.config), 'channel_db')
super().__init__(network, path, Base)
self.num_nodes = 0
self.num_channels = 0
self._channel_updates_for_private_channels = {} # type: Dict[Tuple[bytes, bytes], dict]
self.ca_verifier = LNChannelVerifier(network, self)
self.update_counts()
@sql
def update_counts(self):
self._update_counts()
def _update_counts(self):
self.num_channels = self.DBSession.query(ChannelInfo).count()
self.num_policies = self.DBSession.query(Policy).count()
self.num_nodes = self.DBSession.query(NodeInfo).count()
self.logger.info(f'update counts {self.num_channels} {self.num_policies}')
@sql
def add_recent_peer(self, peer: LNPeerAddr):
now = int(time.time())
node_id = peer.pubkey.hex()
addr = self.DBSession.query(Address).filter_by(node_id=node_id, host=peer.host, port=peer.port).one_or_none()
if addr:
addr.last_connected_date = now
else:
addr = Address(node_id=node_id, host=peer.host, port=peer.port, last_connected_date=now)
self.DBSession.add(addr)
self.DBSession.commit()
@sql
def get_200_randomly_sorted_nodes_not_in(self, node_ids_bytes):
unshuffled = self.DBSession \
.query(NodeInfo) \
.filter(not_(NodeInfo.node_id.in_(x.hex() for x in node_ids_bytes))) \
.limit(200) \
.all()
return random.sample(unshuffled, len(unshuffled))
@sql
def nodes_get(self, node_id):
return self.DBSession \
.query(NodeInfo) \
.filter_by(node_id = node_id.hex()) \
.one_or_none()
@sql
def get_last_good_address(self, node_id) -> Optional[LNPeerAddr]:
r = self.DBSession.query(Address).filter_by(node_id=node_id.hex()).order_by(Address.last_connected_date.desc()).all()
if not r:
return None
addr = r[0]
return LNPeerAddr(addr.host, addr.port, bytes.fromhex(addr.node_id))
@sql
def get_recent_peers(self):
r = self.DBSession.query(Address).filter(Address.last_connected_date.isnot(None)).order_by(Address.last_connected_date.desc()).limit(self.NUM_MAX_RECENT_PEERS).all()
return [LNPeerAddr(x.host, x.port, bytes.fromhex(x.node_id)) for x in r]
@sql
def missing_short_chan_ids(self) -> Set[int]:
expr = not_(Policy.short_channel_id.in_(self.DBSession.query(ChannelInfo.short_channel_id)))
chan_ids_from_policy = set(x[0] for x in self.DBSession.query(Policy.short_channel_id).filter(expr).all())
if chan_ids_from_policy:
return chan_ids_from_policy
return set()
@sql
def add_verified_channel_info(self, short_id, capacity):
# called from lnchannelverifier
channel_info = self.DBSession.query(ChannelInfo).filter_by(short_channel_id = short_id.hex()).one_or_none()
channel_info.trusted = True
channel_info.capacity = capacity
self.DBSession.commit()
@sql
#@profiler
def on_channel_announcement(self, msg_payloads, trusted=False):
if type(msg_payloads) is dict:
msg_payloads = [msg_payloads]
new_channels = {}
for msg in msg_payloads:
short_channel_id = bh2u(msg['short_channel_id'])
if self.DBSession.query(ChannelInfo).filter_by(short_channel_id=short_channel_id).count():
continue
if constants.net.rev_genesis_bytes() != msg['chain_hash']:
self.logger.info("ChanAnn has unexpected chain_hash {}".format(bh2u(msg['chain_hash'])))
continue
try:
channel_info = ChannelInfo.from_msg(msg)
except UnknownEvenFeatureBits:
self.logger.info("unknown feature bits")
continue
channel_info.trusted = trusted
new_channels[short_channel_id] = channel_info
if not trusted:
self.ca_verifier.add_new_channel_info(channel_info.short_channel_id, channel_info.msg_payload)
for channel_info in new_channels.values():
self.DBSession.add(channel_info)
self.DBSession.commit()
#self.logger.info('on_channel_announcement: %d/%d'%(len(new_channels), len(msg_payloads)))
self._update_counts()
self.network.trigger_callback('ln_status')
@sql
def get_last_timestamp(self):
return self._get_last_timestamp()
def _get_last_timestamp(self):
from sqlalchemy.sql import func
r = self.DBSession.query(func.max(Policy.timestamp).label('max_timestamp')).one()
return r.max_timestamp or 0
@sql
#@profiler
def on_channel_update(self, msg_payloads, trusted=False):
if type(msg_payloads) is dict:
msg_payloads = [msg_payloads]
short_channel_ids = [msg_payload['short_channel_id'].hex() for msg_payload in msg_payloads]
channel_infos_list = self.DBSession.query(ChannelInfo).filter(ChannelInfo.short_channel_id.in_(short_channel_ids)).all()
channel_infos = {bfh(x.short_channel_id): x for x in channel_infos_list}
new_policies = {}
for msg_payload in msg_payloads:
short_channel_id = msg_payload['short_channel_id']
if constants.net.rev_genesis_bytes() != msg_payload['chain_hash']:
continue
channel_info = channel_infos.get(short_channel_id)
if not channel_info:
continue
flags = int.from_bytes(msg_payload['channel_flags'], 'big')
direction = flags & FLAG_DIRECTION
node_id = channel_info.node1_id if direction == 0 else channel_info.node2_id
if not trusted and not verify_sig_for_channel_update(msg_payload, bytes.fromhex(node_id)):
continue
short_channel_id = channel_info.short_channel_id
new_policy = Policy.from_msg(msg_payload, node_id, short_channel_id)
#self.logger.info(f'on_channel_update {datetime.fromtimestamp(new_policy.timestamp).ctime()}')
old_policy = self.DBSession.query(Policy).filter_by(short_channel_id=short_channel_id, start_node=node_id).one_or_none()
if old_policy:
if old_policy.timestamp >= new_policy.timestamp:
continue
self.DBSession.delete(old_policy)
p = new_policies.get((short_channel_id, node_id))
if p and p.timestamp >= new_policy.timestamp:
continue
new_policies[(short_channel_id, node_id)] = new_policy
# commit pending removals
self.DBSession.commit()
# add and commit new policies
for new_policy in new_policies.values():
self.DBSession.add(new_policy)
self.DBSession.commit()
if new_policies:
self.logger.info(f'on_channel_update: {len(new_policies)}/{len(msg_payloads)}')
self.logger.info(f'last timestamp: {datetime.fromtimestamp(self._get_last_timestamp()).ctime()}')
self._update_counts()
@sql
#@profiler
def on_node_announcement(self, msg_payloads):
if type(msg_payloads) is dict:
msg_payloads = [msg_payloads]
old_addr = None
new_nodes = {}
new_addresses = {}
for msg_payload in msg_payloads:
pubkey = msg_payload['node_id']
signature = msg_payload['signature']
h = sha256d(msg_payload['raw'][66:])
if not ecc.verify_signature(pubkey, signature, h):
continue
try:
node_info, node_addresses = NodeInfo.from_msg(msg_payload)
except UnknownEvenFeatureBits:
continue
#self.logger.info(f'received node announcement from {datetime.fromtimestamp(node_info.timestamp).ctime()}')
node_id = node_info.node_id
# Ignore node if it has no associated channel (DoS protection)
expr = or_(ChannelInfo.node1_id==node_id, ChannelInfo.node2_id==node_id)
if self.DBSession.query(ChannelInfo.short_channel_id).filter(expr).count() == 0:
#self.logger.info('ignoring orphan node_announcement')
continue
node = self.DBSession.query(NodeInfo).filter_by(node_id=node_id).one_or_none()
if node and node.timestamp >= node_info.timestamp:
continue
node = new_nodes.get(node_id)
if node and node.timestamp >= node_info.timestamp:
continue
new_nodes[node_id] = node_info
for addr in node_addresses:
new_addresses[(addr.node_id,addr.host,addr.port)] = addr
#self.logger.info("on_node_announcement: %d/%d"%(len(new_nodes), len(msg_payloads)))
for node_info in new_nodes.values():
self.DBSession.add(node_info)
for new_addr in new_addresses.values():
old_addr = self.DBSession.query(Address).filter_by(node_id=new_addr.node_id, host=new_addr.host, port=new_addr.port).one_or_none()
if not old_addr:
self.DBSession.add(new_addr)
self.DBSession.commit()
self._update_counts()
self.network.trigger_callback('ln_status')
def get_routing_policy_for_channel(self, start_node_id: bytes,
short_channel_id: bytes) -> Optional[bytes]:
if not start_node_id or not short_channel_id: return None
channel_info = self.get_channel_info(short_channel_id)
if channel_info is not None:
return self.get_policy_for_node(short_channel_id, start_node_id)
msg = self._channel_updates_for_private_channels.get((start_node_id, short_channel_id))
if not msg:
return None
return Policy.from_msg(msg, None, short_channel_id) # won't actually be written to DB
def add_channel_update_for_private_channel(self, msg_payload: dict, start_node_id: bytes):
if not verify_sig_for_channel_update(msg_payload, start_node_id):
return # ignore
short_channel_id = msg_payload['short_channel_id']
self._channel_updates_for_private_channels[(start_node_id, short_channel_id)] = msg_payload
@sql
def remove_channel(self, short_channel_id):
r = self.DBSession.query(ChannelInfo).filter_by(short_channel_id = short_channel_id.hex()).one_or_none()
if not r:
return
self.DBSession.delete(r)
self.DBSession.commit()
def print_graph(self, full_ids=False):
# used for debugging.
# FIXME there is a race here - iterables could change size from another thread
def other_node_id(node_id, channel_id):
channel_info = self.get_channel_info(channel_id)
if node_id == channel_info.node1_id:
other = channel_info.node2_id
else:
other = channel_info.node1_id
return other if full_ids else other[-4:]
print_msg('nodes')
for node in self.DBSession.query(NodeInfo).all():
print_msg(node)
print_msg('channels')
for channel_info in self.DBSession.query(ChannelInfo).all():
short_channel_id = channel_info.short_channel_id
node1 = channel_info.node1_id
node2 = channel_info.node2_id
direction1 = self.get_policy_for_node(channel_info, node1) is not None
direction2 = self.get_policy_for_node(channel_info, node2) is not None
if direction1 and direction2:
direction = 'both'
elif direction1:
direction = 'forward'
elif direction2:
direction = 'backward'
else:
direction = 'none'
print_msg('{}: {}, {}, {}'
.format(bh2u(short_channel_id),
bh2u(node1) if full_ids else bh2u(node1[-4:]),
bh2u(node2) if full_ids else bh2u(node2[-4:]),
direction))
@sql
def get_node_addresses(self, node_info):
return self.DBSession.query(Address).join(NodeInfo).filter_by(node_id = node_info.node_id).all()
@sql
@profiler
def load_data(self):
r = self.DBSession.query(ChannelInfo).all()
self._channels = dict([(bfh(x.short_channel_id), x) for x in r])
r = self.DBSession.query(Policy).filter_by().all()
self._policies = dict([((bfh(x.start_node), bfh(x.short_channel_id)), x) for x in r])
self._channels_for_node = defaultdict(set)
for channel_info in self._channels.values():
self._channels_for_node[bfh(channel_info.node1_id)].add(bfh(channel_info.short_channel_id))
self._channels_for_node[bfh(channel_info.node2_id)].add(bfh(channel_info.short_channel_id))
self.logger.info(f'load data {len(self._channels)} {len(self._policies)} {len(self._channels_for_node)}')
def get_policy_for_node(self, short_channel_id: bytes, node_id: bytes) -> Optional['Policy']:
return self._policies.get((node_id, short_channel_id))
def get_channel_info(self, channel_id: bytes):
return self._channels.get(channel_id)
def get_channels_for_node(self, node_id):
"""Returns the set of channels that have node_id as one of the endpoints."""
return self._channels_for_node.get(node_id)
class RouteEdge(NamedTuple("RouteEdge", [('node_id', bytes),
('short_channel_id', bytes),
('fee_base_msat', int),
('fee_proportional_millionths', int),
('cltv_expiry_delta', int)])):
"""if you travel through short_channel_id, you will reach node_id"""
def fee_for_edge(self, amount_msat: int) -> int:
return self.fee_base_msat \
+ (amount_msat * self.fee_proportional_millionths // 1_000_000)
@classmethod
def from_channel_policy(cls, channel_policy: 'Policy',
short_channel_id: bytes, end_node: bytes) -> 'RouteEdge':
assert type(short_channel_id) is bytes
assert type(end_node) is bytes
return RouteEdge(end_node,
short_channel_id,
channel_policy.fee_base_msat,
channel_policy.fee_proportional_millionths,
channel_policy.cltv_expiry_delta)
def is_sane_to_use(self, amount_msat: int) -> bool:
# TODO revise ad-hoc heuristics
# cltv cannot be more than 2 weeks
if self.cltv_expiry_delta > 14 * 144: return False
total_fee = self.fee_for_edge(amount_msat)
# fees below 50 sat are fine
if total_fee > 50_000:
# fee cannot be higher than amt
if total_fee > amount_msat: return False
# fee cannot be higher than 5000 sat
if total_fee > 5_000_000: return False
# unless amt is tiny, fee cannot be more than 10%
if amount_msat > 1_000_000 and total_fee > amount_msat/10: return False
return True
def is_route_sane_to_use(route: List[RouteEdge], invoice_amount_msat: int, min_final_cltv_expiry: int) -> bool:
"""Run some sanity checks on the whole route, before attempting to use it.
called when we are paying; so e.g. lower cltv is better
"""
if len(route) > NUM_MAX_EDGES_IN_PAYMENT_PATH:
return False
amt = invoice_amount_msat
cltv = min_final_cltv_expiry
for route_edge in reversed(route[1:]):
if not route_edge.is_sane_to_use(amt): return False
amt += route_edge.fee_for_edge(amt)
cltv += route_edge.cltv_expiry_delta
total_fee = amt - invoice_amount_msat
# TODO revise ad-hoc heuristics
# cltv cannot be more than 2 months
if cltv > 60 * 144: return False
# fees below 50 sat are fine
if total_fee > 50_000:
# fee cannot be higher than amt
if total_fee > invoice_amount_msat: return False
# fee cannot be higher than 5000 sat
if total_fee > 5_000_000: return False
# unless amt is tiny, fee cannot be more than 10%
if invoice_amount_msat > 1_000_000 and total_fee > invoice_amount_msat/10: return False
return True
class LNPathFinder(Logger):
def __init__(self, channel_db: ChannelDB):
Logger.__init__(self)
self.channel_db = channel_db
self.blacklist = set()
def _edge_cost(self, short_channel_id: bytes, start_node: bytes, end_node: bytes,
payment_amt_msat: int, ignore_costs=False) -> Tuple[float, int]:
"""Heuristic cost of going through a channel.
Returns (heuristic_cost, fee_for_edge_msat).
"""
channel_info = self.channel_db.get_channel_info(short_channel_id) # type: ChannelInfo
if channel_info is None:
return float('inf'), 0
channel_policy = self.channel_db.get_policy_for_node(short_channel_id, start_node)
if channel_policy is None:
return float('inf'), 0
if channel_policy.is_disabled(): return float('inf'), 0
route_edge = RouteEdge.from_channel_policy(channel_policy, short_channel_id, end_node)
if payment_amt_msat < channel_policy.htlc_minimum_msat:
return float('inf'), 0 # payment amount too little
if channel_info.capacity_sat is not None and \
payment_amt_msat // 1000 > channel_info.capacity_sat:
return float('inf'), 0 # payment amount too large
if channel_policy.htlc_maximum_msat is not None and \
payment_amt_msat > channel_policy.htlc_maximum_msat:
return float('inf'), 0 # payment amount too large
if not route_edge.is_sane_to_use(payment_amt_msat):
return float('inf'), 0 # thanks but no thanks
fee_msat = route_edge.fee_for_edge(payment_amt_msat) if not ignore_costs else 0
# TODO revise
# paying 10 more satoshis ~ waiting one more block
fee_cost = fee_msat / 1000 / 10
cltv_cost = route_edge.cltv_expiry_delta if not ignore_costs else 0
return cltv_cost + fee_cost + 1, fee_msat
@profiler
def find_path_for_payment(self, nodeA: bytes, nodeB: bytes,
invoice_amount_msat: int,
my_channels: List['Channel']=None) -> Sequence[Tuple[bytes, bytes]]:
"""Return a path from nodeA to nodeB.
Returns a list of (node_id, short_channel_id) representing a path.
To get from node ret[n][0] to ret[n+1][0], use channel ret[n+1][1];
i.e. an element reads as, "to get to node_id, travel through short_channel_id"
"""
self.channel_db.load_data()
assert type(nodeA) is bytes
assert type(nodeB) is bytes
assert type(invoice_amount_msat) is int
if my_channels is None: my_channels = []
my_channels = {chan.short_channel_id: chan for chan in my_channels}
# FIXME paths cannot be longer than 21 edges (onion packet)...
# run Dijkstra
# The search is run in the REVERSE direction, from nodeB to nodeA,
# to properly calculate compound routing fees.
distance_from_start = defaultdict(lambda: float('inf'))
distance_from_start[nodeB] = 0
prev_node = {}
nodes_to_explore = queue.PriorityQueue()
nodes_to_explore.put((0, invoice_amount_msat, nodeB)) # order of fields (in tuple) matters!
def inspect_edge():
if edge_channel_id in my_channels:
if edge_startnode == nodeA: # payment outgoing, on our channel
if not my_channels[edge_channel_id].can_pay(amount_msat):
return
else: # payment incoming, on our channel. (funny business, cycle weirdness)
assert edge_endnode == nodeA, (bh2u(edge_startnode), bh2u(edge_endnode))
pass # TODO?
edge_cost, fee_for_edge_msat = self._edge_cost(edge_channel_id,
start_node=edge_startnode,
end_node=edge_endnode,
payment_amt_msat=amount_msat,
ignore_costs=(edge_startnode == nodeA))
alt_dist_to_neighbour = distance_from_start[edge_endnode] + edge_cost
if alt_dist_to_neighbour < distance_from_start[edge_startnode]:
distance_from_start[edge_startnode] = alt_dist_to_neighbour
prev_node[edge_startnode] = edge_endnode, edge_channel_id
amount_to_forward_msat = amount_msat + fee_for_edge_msat
nodes_to_explore.put((alt_dist_to_neighbour, amount_to_forward_msat, edge_startnode))
# main loop of search
while nodes_to_explore.qsize() > 0:
dist_to_edge_endnode, amount_msat, edge_endnode = nodes_to_explore.get()
if edge_endnode == nodeA:
break
if dist_to_edge_endnode != distance_from_start[edge_endnode]:
# queue.PriorityQueue does not implement decrease_priority,
# so instead of decreasing priorities, we add items again into the queue.
# so there are duplicates in the queue, that we discard now:
continue
for edge_channel_id in self.channel_db.get_channels_for_node(edge_endnode):
assert type(edge_channel_id) is bytes
if edge_channel_id in self.blacklist: continue
channel_info = self.channel_db.get_channel_info(edge_channel_id)
edge_startnode = bfh(channel_info.node2_id) if bfh(channel_info.node1_id) == edge_endnode else bfh(channel_info.node1_id)
inspect_edge()
else:
return None # no path found
# backtrack from search_end (nodeA) to search_start (nodeB)
edge_startnode = nodeA
path = []
while edge_startnode != nodeB:
edge_endnode, edge_taken = prev_node[edge_startnode]
path += [(edge_endnode, edge_taken)]
edge_startnode = edge_endnode
return path
def create_route_from_path(self, path, from_node_id: bytes) -> List[RouteEdge]:
assert type(from_node_id) is bytes
if path is None:
raise Exception('cannot create route from None path')
route = []
prev_node_id = from_node_id
for node_id, short_channel_id in path:
channel_policy = self.channel_db.get_routing_policy_for_channel(prev_node_id, short_channel_id)
if channel_policy is None:
raise NoChannelPolicy(short_channel_id)
route.append(RouteEdge.from_channel_policy(channel_policy, short_channel_id, node_id))
prev_node_id = node_id
return route