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#!/usr/bin/env python3
"""
Lightning network interface for Electrum
Derived from https://gist.github.com/AdamISZ/046d05c156aaeb56cc897f85eecb3eb8
"""
from collections import namedtuple, defaultdict, OrderedDict, defaultdict
from .lnutil import Outpoint, ChannelConfig, LocalState, RemoteState, Keypair, OnlyPubkeyKeypair, ChannelConstraints, RevocationStore
from .lnutil import sign_and_get_sig_string, funding_output_script, get_ecdh, get_per_commitment_secret_from_seed
from .lnutil import secret_to_pubkey, LNPeerAddr, PaymentFailure
from .bitcoin import COIN
from ecdsa.util import sigdecode_der, sigencode_string_canonize, sigdecode_string
import queue
import traceback
import json
import asyncio
from concurrent.futures import FIRST_COMPLETED
import os
import time
import binascii
import hashlib
import hmac
import cryptography.hazmat.primitives.ciphers.aead as AEAD
from . import bitcoin
from . import ecc
from . import crypto
from .crypto import sha256
from . import constants
from . import transaction
from .util import PrintError, bh2u, print_error, bfh, aiosafe
from .transaction import opcodes, Transaction, TxOutput
from .lnonion import new_onion_packet, OnionHopsDataSingle, OnionPerHop, decode_onion_error, ONION_FAILURE_CODE_MAP
from .lnaddr import lndecode
from .lnhtlc import UpdateAddHtlc, HTLCStateMachine, RevokeAndAck, SettleHtlc
def channel_id_from_funding_tx(funding_txid, funding_index):
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 LightningError(Exception):
pass
class LightningPeerConnectionClosed(LightningError):
pass
message_types = {}
def handlesingle(x, ma):
"""
Evaluate a term of the simple language used
to specify lightning message field lengths.
If `x` is an integer, it is returned as is,
otherwise it is treated as a variable and
looked up in `ma`.
It the value in `ma` was no integer, it is
assumed big-endian bytes and decoded.
Returns int
"""
try:
x = int(x)
except ValueError:
x = ma[x]
try:
x = int(x)
except ValueError:
x = int.from_bytes(x, byteorder='big')
return x
def calcexp(exp, ma):
"""
Evaluate simple mathematical expression given
in `exp` with variables assigned in the dict `ma`
Returns int
"""
exp = str(exp)
if "*" in exp:
assert "+" not in exp
result = 1
for term in exp.split("*"):
result *= handlesingle(term, ma)
return result
return sum(handlesingle(x, ma) for x in exp.split("+"))
def make_handler(k, v):
"""
Generate a message handler function (taking bytes)
for message type `k` with specification `v`
Check lib/lightning.json, `k` could be 'init',
and `v` could be
{ type: 16, payload: { 'gflen': ..., ... }, ... }
Returns function taking bytes
"""
def handler(data):
nonlocal k, v
ma = {}
pos = 0
for fieldname in v["payload"]:
poslenMap = v["payload"][fieldname]
if "feature" in poslenMap and pos == len(data):
continue
#print(poslenMap["position"], ma)
assert pos == calcexp(poslenMap["position"], ma)
length = poslenMap["length"]
length = calcexp(length, ma)
ma[fieldname] = data[pos:pos+length]
pos += length
assert pos == len(data), (k, pos, len(data))
return k, ma
return handler
path = os.path.join(os.path.dirname(__file__), 'lightning.json')
with open(path) as f:
structured = json.loads(f.read(), object_pairs_hook=OrderedDict)
for k in structured:
v = structured[k]
# these message types are skipped since their types collide
# (for example with pong, which also uses type=19)
# we don't need them yet
if k in ["final_incorrect_cltv_expiry", "final_incorrect_htlc_amount"]:
continue
if len(v["payload"]) == 0:
continue
try:
num = int(v["type"])
except ValueError:
#print("skipping", k)
continue
byts = num.to_bytes(2, 'big')
assert byts not in message_types, (byts, message_types[byts].__name__, k)
names = [x.__name__ for x in message_types.values()]
assert k + "_handler" not in names, (k, names)
message_types[byts] = make_handler(k, v)
message_types[byts].__name__ = k + "_handler"
assert message_types[b"\x00\x10"].__name__ == "init_handler"
def decode_msg(data):
"""
Decode Lightning message by reading the first
two bytes to determine message type.
Returns message type string and parsed message contents dict
"""
typ = data[:2]
k, parsed = message_types[typ](data[2:])
return k, parsed
def gen_msg(msg_type, **kwargs):
"""
Encode kwargs into a Lightning message (bytes)
of the type given in the msg_type string
"""
typ = structured[msg_type]
data = int(typ["type"]).to_bytes(2, 'big')
lengths = {}
for k in typ["payload"]:
poslenMap = typ["payload"][k]
if "feature" in poslenMap: continue
leng = calcexp(poslenMap["length"], lengths)
try:
clone = dict(lengths)
clone.update(kwargs)
leng = calcexp(poslenMap["length"], clone)
except KeyError:
pass
try:
param = kwargs[k]
except KeyError:
param = 0
try:
if not isinstance(param, bytes):
assert isinstance(param, int), "field {} is neither bytes or int".format(k)
param = param.to_bytes(leng, 'big')
except ValueError:
raise Exception("{} does not fit in {} bytes".format(k, leng))
lengths[k] = len(param)
if lengths[k] != leng:
raise Exception("field {} is {} bytes long, should be {} bytes long".format(k, lengths[k], leng))
data += param
return data
class HandshakeState(object):
prologue = b"lightning"
protocol_name = b"Noise_XK_secp256k1_ChaChaPoly_SHA256"
handshake_version = b"\x00"
def __init__(self, responder_pub):
self.responder_pub = responder_pub
self.h = sha256(self.protocol_name)
self.ck = self.h
self.update(self.prologue)
self.update(self.responder_pub)
def update(self, data):
self.h = sha256(self.h + data)
return self.h
class HandshakeFailed(Exception): pass
def get_nonce_bytes(n):
"""BOLT 8 requires the nonce to be 12 bytes, 4 bytes leading
zeroes and 8 bytes little endian encoded 64 bit integer.
"""
return b"\x00"*4 + n.to_bytes(8, 'little')
def aead_encrypt(k, nonce, associated_data, data):
nonce_bytes = get_nonce_bytes(nonce)
a = AEAD.ChaCha20Poly1305(k)
return a.encrypt(nonce_bytes, data, associated_data)
def aead_decrypt(k, nonce, associated_data, data):
nonce_bytes = get_nonce_bytes(nonce)
a = AEAD.ChaCha20Poly1305(k)
#raises InvalidTag exception if it's not valid
return a.decrypt(nonce_bytes, data, associated_data)
def get_bolt8_hkdf(salt, ikm):
"""RFC5869 HKDF instantiated in the specific form
used in Lightning BOLT 8:
Extract and expand to 64 bytes using HMAC-SHA256,
with info field set to a zero length string as per BOLT8
Return as two 32 byte fields.
"""
#Extract
prk = hmac.new(salt, msg=ikm, digestmod=hashlib.sha256).digest()
assert len(prk) == 32
#Expand
info = b""
T0 = b""
T1 = hmac.new(prk, T0 + info + b"\x01", digestmod=hashlib.sha256).digest()
T2 = hmac.new(prk, T1 + info + b"\x02", digestmod=hashlib.sha256).digest()
assert len(T1 + T2) == 64
return T1, T2
def act1_initiator_message(hs, epriv, epub):
hs.update(epub)
ss = get_ecdh(epriv, hs.responder_pub)
ck2, temp_k1 = get_bolt8_hkdf(hs.ck, ss)
hs.ck = ck2
c = aead_encrypt(temp_k1, 0, hs.h, b"")
#for next step if we do it
hs.update(c)
msg = hs.handshake_version + epub + c
assert len(msg) == 50
return msg
def privkey_to_pubkey(priv: bytes) -> bytes:
return ecc.ECPrivkey(priv[:32]).get_public_key_bytes()
def create_ephemeral_key() -> (bytes, bytes):
privkey = ecc.ECPrivkey.generate_random_key()
return privkey.get_secret_bytes(), privkey.get_public_key_bytes()
class Peer(PrintError):
def __init__(self, lnworker, host, port, pubkey, request_initial_sync=False):
self.exception = None # set by aiosafe
self.host = host
self.port = port
self.pubkey = pubkey
self.peer_addr = LNPeerAddr(host, port, pubkey)
self.lnworker = lnworker
self.privkey = lnworker.privkey
self.network = lnworker.network
self.lnwatcher = lnworker.network.lnwatcher
self.channel_db = lnworker.network.channel_db
self.read_buffer = b''
self.ping_time = 0
self.initialized = asyncio.Future()
self.channel_accepted = defaultdict(asyncio.Queue)
self.channel_reestablished = defaultdict(asyncio.Future)
self.funding_signed = defaultdict(asyncio.Queue)
self.revoke_and_ack = defaultdict(asyncio.Queue)
self.update_fulfill_htlc = defaultdict(asyncio.Queue)
self.commitment_signed = defaultdict(asyncio.Queue)
self.announcement_signatures = defaultdict(asyncio.Queue)
self.update_fail_htlc = defaultdict(asyncio.Queue)
self.localfeatures = (0x08 if request_initial_sync else 0)
self.invoices = lnworker.invoices
self.attempted_route = {}
@property
def channels(self):
return self.lnworker.channels_for_peer(self.pubkey)
def diagnostic_name(self):
return 'lnbase:' + str(self.host)
def ping_if_required(self):
if time.time() - self.ping_time > 120:
self.send_message(gen_msg('ping', num_pong_bytes=4, byteslen=4))
self.ping_time = time.time()
def send_message(self, msg):
message_type, payload = decode_msg(msg)
self.print_error("Sending '%s'"%message_type.upper())
l = len(msg).to_bytes(2, 'big')
lc = aead_encrypt(self.sk, self.sn(), b'', l)
c = aead_encrypt(self.sk, self.sn(), b'', msg)
assert len(lc) == 18
assert len(c) == len(msg) + 16
self.writer.write(lc+c)
async def read_message(self):
rn_l, rk_l = self.rn()
rn_m, rk_m = self.rn()
while True:
if len(self.read_buffer) >= 18:
lc = self.read_buffer[:18]
l = aead_decrypt(rk_l, rn_l, b'', lc)
length = int.from_bytes(l, 'big')
offset = 18 + length + 16
if len(self.read_buffer) >= offset:
c = self.read_buffer[18:offset]
self.read_buffer = self.read_buffer[offset:]
msg = aead_decrypt(rk_m, rn_m, b'', c)
return msg
try:
s = await self.reader.read(2**10)
except:
s = None
if not s:
raise LightningPeerConnectionClosed()
self.read_buffer += s
async def handshake(self):
hs = HandshakeState(self.pubkey)
# Get a new ephemeral key
epriv, epub = create_ephemeral_key()
msg = act1_initiator_message(hs, epriv, epub)
# act 1
self.writer.write(msg)
rspns = await self.reader.read(2**10)
if len(rspns) != 50:
raise HandshakeFailed("Lightning handshake act 1 response has bad length, are you sure this is the right pubkey? " + str(bh2u(self.pubkey)))
hver, alice_epub, tag = rspns[0], rspns[1:34], rspns[34:]
if bytes([hver]) != hs.handshake_version:
raise HandshakeFailed("unexpected handshake version: {}".format(hver))
# act 2
hs.update(alice_epub)
ss = get_ecdh(epriv, alice_epub)
ck, temp_k2 = get_bolt8_hkdf(hs.ck, ss)
hs.ck = ck
p = aead_decrypt(temp_k2, 0, hs.h, tag)
hs.update(tag)
# act 3
my_pubkey = privkey_to_pubkey(self.privkey)
c = aead_encrypt(temp_k2, 1, hs.h, my_pubkey)
hs.update(c)
ss = get_ecdh(self.privkey[:32], alice_epub)
ck, temp_k3 = get_bolt8_hkdf(hs.ck, ss)
hs.ck = ck
t = aead_encrypt(temp_k3, 0, hs.h, b'')
self.sk, self.rk = get_bolt8_hkdf(hs.ck, b'')
msg = hs.handshake_version + c + t
self.writer.write(msg)
# init counters
self._sn = 0
self._rn = 0
self.r_ck = ck
self.s_ck = ck
def rn(self):
o = self._rn, self.rk
self._rn += 1
if self._rn == 1000:
self.r_ck, self.rk = get_bolt8_hkdf(self.r_ck, self.rk)
self._rn = 0
return o
def sn(self):
o = self._sn
self._sn += 1
if self._sn == 1000:
self.s_ck, self.sk = get_bolt8_hkdf(self.s_ck, self.sk)
self._sn = 0
return o
def process_message(self, message):
message_type, payload = decode_msg(message)
#self.print_error("Received '%s'" % message_type.upper())
try:
f = getattr(self, 'on_' + message_type)
except AttributeError:
self.print_error("Received '%s'" % message_type.upper(), payload)
return
# raw message is needed to check signature
if message_type=='node_announcement':
payload['raw'] = message
f(payload)
def on_error(self, payload):
self.print_error("error", payload["data"].decode("ascii"))
def on_ping(self, payload):
l = int.from_bytes(payload['num_pong_bytes'], 'big')
self.send_message(gen_msg('pong', byteslen=l))
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_node_announcement(self, payload):
self.channel_db.on_node_announcement(payload)
self.network.trigger_callback('ln_status')
def on_init(self, payload):
pass
def on_channel_update(self, payload):
self.channel_db.on_channel_update(payload)
def on_channel_announcement(self, payload):
self.channel_db.on_channel_announcement(payload)
def on_announcement_signatures(self, payload):
channel_id = payload['channel_id']
chan = self.channels[payload['channel_id']]
if chan.local_state.was_announced:
h, local_node_sig, local_bitcoin_sig = self.send_announcement_signatures(chan)
else:
self.announcement_signatures[channel_id].put_nowait(payload)
async def initialize(self):
self.reader, self.writer = await asyncio.open_connection(self.host, self.port)
await self.handshake()
# send init
self.send_message(gen_msg("init", gflen=0, lflen=1, localfeatures=self.localfeatures))
# read init
msg = await self.read_message()
self.process_message(msg)
self.initialized.set_result(True)
@aiosafe
async def main_loop(self):
await asyncio.wait_for(self.initialize(), 5)
self.channel_db.add_recent_peer(self.peer_addr)
# loop
while True:
self.ping_if_required()
msg = await self.read_message()
self.process_message(msg)
def close_and_cleanup(self):
try:
self.writer.close()
except:
pass
for chan in self.channels.values():
chan.set_state('DISCONNECTED')
self.network.trigger_callback('channel', chan)
@aiosafe
async def channel_establishment_flow(self, wallet, config, password, funding_sat, push_msat, temp_channel_id, sweep_address):
await self.initialized
# see lnd/keychain/derivation.go
keyfamilymultisig = 0
keyfamilyrevocationbase = 1
keyfamilyhtlcbase = 2
keyfamilypaymentbase = 3
keyfamilydelaybase = 4
keyfamilyrevocationroot = 5
keyfamilynodekey = 6 # TODO currently unused
# amounts
local_feerate = self.current_feerate_per_kw()
# key derivation
keypair_generator = lambda family, i: Keypair(*wallet.keystore.get_keypair([family, i], password))
local_config=ChannelConfig(
payment_basepoint=keypair_generator(keyfamilypaymentbase, 0),
multisig_key=keypair_generator(keyfamilymultisig, 0),
htlc_basepoint=keypair_generator(keyfamilyhtlcbase, 0),
delayed_basepoint=keypair_generator(keyfamilydelaybase, 0),
revocation_basepoint=keypair_generator(keyfamilyrevocationbase, 0),
to_self_delay=143,
dust_limit_sat=546,
max_htlc_value_in_flight_msat=0xffffffffffffffff,
max_accepted_htlcs=5
)
# TODO derive this?
per_commitment_secret_seed = 0x1f1e1d1c1b1a191817161514131211100f0e0d0c0b0a09080706050403020100.to_bytes(32, 'big')
per_commitment_secret_index = RevocationStore.START_INDEX
# for the first commitment transaction
per_commitment_secret_first = get_per_commitment_secret_from_seed(per_commitment_secret_seed, per_commitment_secret_index)
per_commitment_point_first = secret_to_pubkey(int.from_bytes(per_commitment_secret_first, 'big'))
msg = gen_msg(
"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=local_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=0x01, # publicly announcing channel
channel_reserve_satoshis=546
)
self.send_message(msg)
payload = await self.channel_accepted[temp_channel_id].get()
remote_per_commitment_point = payload['first_per_commitment_point']
remote_config=ChannelConfig(
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'], byteorder='big'),
dust_limit_sat=int.from_bytes(payload['dust_limit_satoshis'], byteorder='big'),
max_htlc_value_in_flight_msat=int.from_bytes(payload['max_htlc_value_in_flight_msat'], 'big'),
max_accepted_htlcs=int.from_bytes(payload["max_accepted_htlcs"], 'big')
)
funding_txn_minimum_depth = int.from_bytes(payload['minimum_depth'], 'big')
assert remote_config.dust_limit_sat < 600
assert int.from_bytes(payload['htlc_minimum_msat'], 'big') < 600 * 1000
assert remote_config.max_htlc_value_in_flight_msat >= 198 * 1000 * 1000, remote_config.max_htlc_value_in_flight_msat
self.print_error('remote delay', remote_config.to_self_delay)
self.print_error('funding_txn_minimum_depth', funding_txn_minimum_depth)
# create funding tx
redeem_script = funding_output_script(local_config, remote_config)
funding_address = bitcoin.redeem_script_to_address('p2wsh', redeem_script)
funding_output = TxOutput(bitcoin.TYPE_ADDRESS, funding_address, funding_sat)
funding_tx = wallet.mktx([funding_output], password, config, 1000)
funding_txid = funding_tx.txid()
funding_index = funding_tx.outputs().index(funding_output)
# compute amounts
local_amount = funding_sat*1000 - push_msat
remote_amount = push_msat
# remote commitment transaction
channel_id, funding_txid_bytes = channel_id_from_funding_tx(funding_txid, funding_index)
their_revocation_store = RevocationStore()
chan = {
"node_id": self.pubkey,
"channel_id": channel_id,
"short_channel_id": None,
"funding_outpoint": Outpoint(funding_txid, funding_index),
"local_config": local_config,
"remote_config": remote_config,
"remote_state": RemoteState(
ctn = -1,
next_per_commitment_point=remote_per_commitment_point,
current_per_commitment_point=None,
amount_msat=remote_amount,
revocation_store=their_revocation_store,
next_htlc_id = 0,
feerate=local_feerate
),
"local_state": LocalState(
ctn = -1,
per_commitment_secret_seed=per_commitment_secret_seed,
amount_msat=local_amount,
next_htlc_id = 0,
funding_locked_received = False,
was_announced = False,
current_commitment_signature = None,
current_htlc_signatures = None,
feerate=local_feerate
),
"constraints": ChannelConstraints(capacity=funding_sat, is_initiator=True, funding_txn_minimum_depth=funding_txn_minimum_depth),
"remote_commitment_to_be_revoked": None,
}
m = HTLCStateMachine(chan)
m.lnwatcher = self.lnwatcher
m.sweep_address = sweep_address
sig_64, _ = m.sign_next_commitment()
self.send_message(gen_msg("funding_created",
temporary_channel_id=temp_channel_id,
funding_txid=funding_txid_bytes,
funding_output_index=funding_index,
signature=sig_64))
payload = await self.funding_signed[channel_id].get()
self.print_error('received funding_signed')
remote_sig = payload['signature']
m.receive_new_commitment(remote_sig, [])
# broadcast funding tx
success, _txid = await self.network.broadcast_transaction(funding_tx)
assert success, success
m.remote_commitment_to_be_revoked = m.pending_remote_commitment
m.remote_state = m.remote_state._replace(ctn=0)
m.local_state = m.local_state._replace(ctn=0, current_commitment_signature=remote_sig)
m.set_state('OPENING')
return m
@aiosafe
async def reestablish_channel(self, chan):
await self.initialized
chan_id = chan.channel_id
if chan.get_state() != 'DISCONNECTED':
self.print_error('reestablish_channel was called but channel {} already in state {}'
.format(chan_id, chan.get_state()))
return
chan.set_state('REESTABLISHING')
self.network.trigger_callback('channel', chan)
self.send_message(gen_msg("channel_reestablish",
channel_id=chan_id,
next_local_commitment_number=chan.local_state.ctn+1,
next_remote_revocation_number=chan.remote_state.ctn
))
await self.channel_reestablished[chan_id]
chan.set_state('OPENING')
if chan.local_state.funding_locked_received and chan.short_channel_id:
self.mark_open(chan)
self.network.trigger_callback('channel', chan)
def on_channel_reestablish(self, payload):
chan_id = payload["channel_id"]
self.print_error("Received channel_reestablish", bh2u(chan_id))
chan = self.channels.get(chan_id)
if not chan:
print("Warning: received unknown channel_reestablish", bh2u(chan_id))
return
channel_reestablish_msg = payload
remote_ctn = int.from_bytes(channel_reestablish_msg["next_local_commitment_number"], 'big')
if remote_ctn != chan.remote_state.ctn + 1:
raise Exception("expected remote ctn {}, got {}".format(chan.remote_state.ctn + 1, remote_ctn))
local_ctn = int.from_bytes(channel_reestablish_msg["next_remote_revocation_number"], 'big')
if local_ctn != chan.local_state.ctn:
raise Exception("expected local ctn {}, got {}".format(chan.local_state.ctn, local_ctn))
try:
their = channel_reestablish_msg["my_current_per_commitment_point"]
except KeyError: # no data_protect option
self.channel_reestablished[chan_id].set_result(True)
return
our = chan.remote_state.current_per_commitment_point
if our is None:
our = chan.remote_state.next_per_commitment_point
if our != their:
raise Exception("Remote PCP mismatch: {} {}".format(bh2u(our), bh2u(their)))
self.channel_reestablished[chan_id].set_result(True)
def funding_locked(self, chan):
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.local_state.per_commitment_secret_seed, per_commitment_secret_index), 'big'))
self.send_message(gen_msg("funding_locked", channel_id=channel_id, next_per_commitment_point=per_commitment_point_second))
if chan.local_state.funding_locked_received:
self.mark_open(chan)
def on_funding_locked(self, payload):
channel_id = payload['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.local_state.funding_locked_received:
our_next_point = chan.remote_state.next_per_commitment_point
their_next_point = payload["next_per_commitment_point"]
new_remote_state = chan.remote_state._replace(next_per_commitment_point=their_next_point, current_per_commitment_point=our_next_point)
new_local_state = chan.local_state._replace(funding_locked_received = True)
chan.remote_state=new_remote_state
chan.local_state=new_local_state
self.lnworker.save_channel(chan)
if chan.short_channel_id:
self.mark_open(chan)
def on_network_update(self, chan, funding_tx_depth):
"""
Only called when the channel is OPEN.
Runs on the Network thread.
"""
if not chan.local_state.was_announced and funding_tx_depth >= 6:
chan.local_state=chan.local_state._replace(was_announced=True)
coro = self.handle_announcements(chan)
self.lnworker.save_channel(chan)
asyncio.run_coroutine_threadsafe(coro, self.network.asyncio_loop)
@aiosafe
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.remote_config.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 = [local_node_sig, remote_node_sig]
bitcoin_sigs = [local_bitcoin_sig, remote_bitcoin_sig]
node_ids = [privkey_to_pubkey(self.privkey), self.pubkey]
bitcoin_keys = [chan.local_config.multisig_key.pubkey, chan.remote_config.multisig_key.pubkey]
if node_ids[0] > node_ids[1]:
node_sigs.reverse()
bitcoin_sigs.reverse()
node_ids.reverse()
bitcoin_keys.reverse()
channel_announcement = gen_msg("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]
)
self.send_message(channel_announcement)
print("SENT CHANNEL ANNOUNCEMENT")
def mark_open(self, chan):
if chan.get_state() == "OPEN":
return
# NOTE: even closed channels will be temporarily marked "OPEN"
assert chan.local_state.funding_locked_received
chan.set_state("OPEN")
self.network.trigger_callback('channel', chan)
# add channel to database
node_ids = [self.pubkey, self.lnworker.pubkey]
bitcoin_keys = [chan.local_config.multisig_key.pubkey, chan.remote_config.multisig_key.pubkey]
sorted_node_ids = list(sorted(node_ids))
if sorted_node_ids != node_ids:
node_ids = sorted_node_ids
bitcoin_keys.reverse()
now = int(time.time()).to_bytes(4, byteorder="big")
self.channel_db.on_channel_announcement({"short_channel_id": chan.short_channel_id, "node_id_1": node_ids[0], "node_id_2": 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)
self.channel_db.on_channel_update({"short_channel_id": chan.short_channel_id, 'flags': b'\x01', 'cltv_expiry_delta': b'\x90',
'htlc_minimum_msat': b'\x03\xe8', 'fee_base_msat': b'\x03\xe8', 'fee_proportional_millionths': b'\x01',
'chain_hash': constants.net.rev_genesis_bytes(), 'timestamp': now},
trusted=True)
self.channel_db.on_channel_update({"short_channel_id": chan.short_channel_id, 'flags': b'\x00', 'cltv_expiry_delta': b'\x90',
'htlc_minimum_msat': b'\x03\xe8', 'fee_base_msat': b'\x03\xe8', 'fee_proportional_millionths': b'\x01',
'chain_hash': constants.net.rev_genesis_bytes(), 'timestamp': now},
trusted=True)
self.print_error("CHANNEL OPENING COMPLETED")
def send_announcement_signatures(self, chan):
bitcoin_keys = [chan.local_config.multisig_key.pubkey,
chan.remote_config.multisig_key.pubkey]
node_ids = [privkey_to_pubkey(self.privkey),
self.pubkey]
sorted_node_ids = list(sorted(node_ids))
if sorted_node_ids != node_ids:
node_ids = sorted_node_ids
bitcoin_keys.reverse()
chan_ann = gen_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 = bitcoin.Hash(to_hash)
bitcoin_signature = ecc.ECPrivkey(chan.local_config.multisig_key.privkey).sign(h, sigencode_string_canonize, sigdecode_string)
node_signature = ecc.ECPrivkey(self.privkey).sign(h, sigencode_string_canonize, sigdecode_string)
self.send_message(gen_msg("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")
key = (channel_id, htlc_id)
route = self.attempted_route[key]
failure_msg, sender_idx = decode_onion_error(payload["reason"], [x.node_id for x in route], self.secret_key)
code = failure_msg.code
code_name = ONION_FAILURE_CODE_MAP.get(code, 'unknown_error!!')
data = failure_msg.data
print("UPDATE_FAIL_HTLC", code_name, code, data)
try:
short_chan_id = route[sender_idx + 1].short_channel_id
except IndexError:
print("payment destination reported error")
else:
# TODO this should depend on the error
# also, we need finer blacklisting (directed edges; nodes)
self.network.path_finder.blacklist.add(short_chan_id)
self.update_fail_htlc[payload["channel_id"]].put_nowait("HTLC failure with code {} ({})".format(code, code_name))
@aiosafe
async def pay(self, path, chan, amount_msat, payment_hash, pubkey_in_invoice, min_final_cltv_expiry):
# FIXME aiosafe is breaking "raise PaymentFailure"
assert chan.get_state() == "OPEN", chan.get_state()
assert amount_msat > 0, "amount_msat is not greater zero"
height = self.network.get_local_height()
route = self.network.path_finder.create_route_from_path(path, self.lnworker.pubkey)
hops_data = []
sum_of_deltas = sum(route_edge.channel_policy.cltv_expiry_delta for route_edge in route[1:])
total_fee = 0
final_cltv_expiry_without_deltas = (height + min_final_cltv_expiry)
final_cltv_expiry_with_deltas = final_cltv_expiry_without_deltas + sum_of_deltas
for idx, route_edge in enumerate(route[1:]):
hops_data += [OnionHopsDataSingle(OnionPerHop(route_edge.short_channel_id, amount_msat.to_bytes(8, "big"), final_cltv_expiry_without_deltas.to_bytes(4, "big")))]
total_fee += route_edge.channel_policy.fee_base_msat + ( amount_msat * route_edge.channel_policy.fee_proportional_millionths // 1000000 )
associated_data = payment_hash
self.secret_key = os.urandom(32)
hops_data += [OnionHopsDataSingle(OnionPerHop(b"\x00"*8, amount_msat.to_bytes(8, "big"), (final_cltv_expiry_without_deltas).to_bytes(4, "big")))]
onion = new_onion_packet([x.node_id for x in route], self.secret_key, hops_data, associated_data)
amount_msat += total_fee
# FIXME this below will probably break with multiple HTLCs
msat_local = chan.local_state.amount_msat - amount_msat
msat_remote = chan.remote_state.amount_msat + amount_msat
htlc = UpdateAddHtlc(amount_msat, payment_hash, final_cltv_expiry_with_deltas)
# FIXME if we raise here, this channel will not get blacklisted, and the payment can never succeed,
# as we will just keep retrying this same path. using the current blacklisting is not a solution as
# then no other payment can use this channel either.
# we need finer blacklisting -- e.g. a blacklist for just this "payment session"?
# or blacklist entries could store an msat value and also expire
if len(chan.htlcs_in_local) + 1 > chan.remote_config.max_accepted_htlcs:
raise PaymentFailure('too many HTLCs already in channel')
if chan.htlcsum(chan.htlcs_in_local) + amount_msat > chan.remote_config.max_htlc_value_in_flight_msat:
raise PaymentFailure('HTLC value sum would exceed max allowed: {} msat'.format(chan.remote_config.max_htlc_value_in_flight_msat))
if msat_local < 0:
# FIXME what about channel_reserve_satoshis? will the remote fail the channel if we go below? test.
raise PaymentFailure('not enough local balance')
self.send_message(gen_msg("update_add_htlc", channel_id=chan.channel_id, id=chan.local_state.next_htlc_id, cltv_expiry=final_cltv_expiry_with_deltas, amount_msat=amount_msat, payment_hash=payment_hash, onion_routing_packet=onion.to_bytes()))
chan.add_htlc(htlc)
self.attempted_route[(chan.channel_id, htlc.htlc_id)] = route
sig_64, htlc_sigs = chan.sign_next_commitment()
self.send_message(gen_msg("commitment_signed", channel_id=chan.channel_id, signature=sig_64, num_htlcs=len(htlc_sigs), htlc_signature=b"".join(htlc_sigs)))
await self.receive_revoke(chan)
await self.receive_commitment(chan)
self.revoke(chan)
fulfill_coro = asyncio.ensure_future(self.update_fulfill_htlc[chan.channel_id].get())
failure_coro = asyncio.ensure_future(self.update_fail_htlc[chan.channel_id].get())
done, pending = await asyncio.wait([fulfill_coro, failure_coro], return_when=FIRST_COMPLETED)
# TODO what if HTLC gets stuck in multihop payment (A->B->C->D->E; on the way back C goes offline)
payment_succeeded = False
if failure_coro.done():
fulfill_coro.cancel()
sig_64, htlc_sigs = chan.sign_next_commitment()
self.send_message(gen_msg("commitment_signed", channel_id=chan.channel_id, signature=sig_64, num_htlcs=len(htlc_sigs), htlc_signature=b"".join(htlc_sigs)))
await self.receive_revoke(chan)
chan.fail_htlc(htlc)
await self.receive_commitment(chan)
self.revoke(chan)
sig_64, htlc_sigs = chan.sign_next_commitment()
res = failure_coro.result()
else:
failure_coro.cancel()
update_fulfill_htlc_msg = fulfill_coro.result()
preimage = update_fulfill_htlc_msg["payment_preimage"]
chan.receive_htlc_settle(preimage, int.from_bytes(update_fulfill_htlc_msg["id"], "big"))
await self.receive_commitment(chan)
self.revoke(chan)
# FIXME why is this not using the HTLC state machine?
bare_ctx = chan.make_commitment(chan.remote_state.ctn + 1, False, chan.remote_state.next_per_commitment_point,
msat_remote, msat_local)
self.lnwatcher.process_new_offchain_ctx(chan, bare_ctx, ours=False)
sig_64 = sign_and_get_sig_string(bare_ctx, chan.local_config, chan.remote_config)
res = bh2u(preimage)
payment_succeeded = True
self.send_message(gen_msg("commitment_signed", channel_id=chan.channel_id, signature=sig_64, num_htlcs=0))
await self.receive_revoke(chan)
self.lnworker.save_channel(chan)
if payment_succeeded:
return res
else:
raise PaymentFailure(res)
async def receive_revoke(self, m):
revoke_and_ack_msg = await self.revoke_and_ack[m.channel_id].get()
m.receive_revocation(RevokeAndAck(revoke_and_ack_msg["per_commitment_secret"], revoke_and_ack_msg["next_per_commitment_point"]))
def revoke(self, m):
rev, _ = m.revoke_current_commitment()
self.send_message(gen_msg("revoke_and_ack",
channel_id=m.channel_id,
per_commitment_secret=rev.per_commitment_secret,
next_per_commitment_point=rev.next_per_commitment_point))
async def receive_commitment(self, m, commitment_signed_msg=None):
if commitment_signed_msg is None:
commitment_signed_msg = await self.commitment_signed[m.channel_id].get()
data = commitment_signed_msg["htlc_signature"]
htlc_sigs = [data[i:i+64] for i in range(0, len(data), 64)]
m.receive_new_commitment(commitment_signed_msg["signature"], htlc_sigs)
return len(htlc_sigs)
@aiosafe
async def receive_commitment_revoke_ack(self, htlc, decoded, payment_preimage):
chan = self.channels[htlc['channel_id']]
channel_id = chan.channel_id
expected_received_msat = int(decoded.amount * bitcoin.COIN * 1000)
htlc_id = int.from_bytes(htlc["id"], 'big')
assert htlc_id == chan.remote_state.next_htlc_id, (htlc_id, chan.remote_state.next_htlc_id)
assert chan.get_state() == "OPEN"
cltv_expiry = int.from_bytes(htlc["cltv_expiry"], 'big')
# TODO verify sanity of their cltv expiry
amount_msat = int.from_bytes(htlc["amount_msat"], 'big')
assert amount_msat == expected_received_msat
payment_hash = htlc["payment_hash"]
htlc = UpdateAddHtlc(amount_msat, payment_hash, cltv_expiry)
chan.receive_htlc(htlc)
assert (await self.receive_commitment(chan)) <= 1
self.revoke(chan)
sig_64, htlc_sigs = chan.sign_next_commitment()
htlc_sig = b''.join(htlc_sigs)
self.send_message(gen_msg("commitment_signed", channel_id=channel_id, signature=sig_64, num_htlcs=len(htlc_sigs), htlc_signature=htlc_sig))
await self.receive_revoke(chan)
chan.settle_htlc(payment_preimage, htlc_id)
self.send_message(gen_msg("update_fulfill_htlc", channel_id=channel_id, id=htlc_id, payment_preimage=payment_preimage))
# remote commitment transaction without htlcs
# FIXME why is this not using the HTLC state machine?
bare_ctx = chan.make_commitment(chan.remote_state.ctn + 1, False, chan.remote_state.next_per_commitment_point,
chan.remote_state.amount_msat - expected_received_msat, chan.local_state.amount_msat + expected_received_msat)
self.lnwatcher.process_new_offchain_ctx(chan, bare_ctx, ours=False)
sig_64 = sign_and_get_sig_string(bare_ctx, chan.local_config, chan.remote_config)
self.send_message(gen_msg("commitment_signed", channel_id=channel_id, signature=sig_64, num_htlcs=0))
revoke_coro = asyncio.ensure_future(self.revoke_and_ack[chan.channel_id].get())
commit_coro = asyncio.ensure_future(self.commitment_signed[chan.channel_id].get())
_done, _pending = await asyncio.wait([revoke_coro, commit_coro], return_when=FIRST_COMPLETED)
def process_revoke(revoke_and_ack_msg):
chan.receive_revocation(RevokeAndAck(revoke_and_ack_msg["per_commitment_secret"], revoke_and_ack_msg["next_per_commitment_point"]))
if commit_coro.done():
# this branch is taken with lnd after a fee update (initiated by us, of course)
await revoke_coro
process_revoke(revoke_coro.result())
self.revoke(chan)
await self.receive_commitment(chan)
self.revoke(chan)
sig_64, htlc_sigs = chan.sign_next_commitment()
self.send_message(gen_msg("commitment_signed", channel_id=chan.channel_id, signature=sig_64, num_htlcs=len(htlc_sigs), htlc_signature=b"".join(htlc_sigs)))
await self.receive_revoke(chan)
elif revoke_coro.done():
process_revoke(revoke_coro.result())
await commit_coro
await self.receive_commitment(chan, commit_coro.result())
self.revoke(chan)
self.lnworker.save_channel(chan)
def on_commitment_signed(self, payload):
self.print_error("commitment_signed", payload)
channel_id = payload['channel_id']
chan = self.channels[channel_id]
chan.local_state=chan.local_state._replace(
current_commitment_signature=payload['signature'],
current_htlc_signatures=payload['htlc_signature'])
self.lnworker.save_channel(chan)
self.commitment_signed[channel_id].put_nowait(payload)
def on_update_fulfill_htlc(self, payload):
self.print_error("update_fulfill")
channel_id = payload["channel_id"]
self.update_fulfill_htlc[channel_id].put_nowait(payload)
def on_update_fail_malformed_htlc(self, payload):
self.on_error(payload)
def on_update_add_htlc(self, payload):
# no onion routing for the moment: we assume we are the end node
self.print_error('on_update_add_htlc', payload)
# check if this in our list of requests
payment_hash = payload["payment_hash"]
for k in self.invoices.keys():
preimage = bfh(k)
if sha256(preimage) == payment_hash:
req = self.invoices[k]
decoded = lndecode(req, expected_hrp=constants.net.SEGWIT_HRP)
coro = self.receive_commitment_revoke_ack(payload, decoded, preimage)
asyncio.run_coroutine_threadsafe(coro, self.network.asyncio_loop)
break
else:
assert False
def on_revoke_and_ack(self, payload):
print("got revoke_and_ack")
channel_id = payload["channel_id"]
self.revoke_and_ack[channel_id].put_nowait(payload)
def on_update_fee(self, payload):
channel_id = payload["channel_id"]
self.channels[channel_id].receive_update_fee(int.from_bytes(payload["feerate_per_kw"], "big"))
def on_bitcoin_fee_update(self, chan):
"""
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.current_feerate_per_kw()
self.print_error("current feerate", chan.remote_state.feerate)
self.print_error("new feerate", feerate_per_kw)
if feerate_per_kw < chan.remote_state.feerate / 2:
self.print_error("FEES HAVE FALLEN")
chan.update_fee(feerate_per_kw)
elif feerate_per_kw > chan.remote_state.feerate * 2:
self.print_error("FEES HAVE RISEN")
chan.update_fee(feerate_per_kw)
else:
return
self.send_message(gen_msg("update_fee", channel_id=chan.channel_id, feerate_per_kw=feerate_per_kw))
self.lnworker.save_channel(chan)
def current_feerate_per_kw(self):
from .simple_config import FEE_LN_ETA_TARGET, FEERATE_FALLBACK_STATIC_FEE
feerate_per_kvbyte = self.network.config.eta_target_to_fee(FEE_LN_ETA_TARGET)
if feerate_per_kvbyte is None:
feerate_per_kvbyte = FEERATE_FALLBACK_STATIC_FEE
return max(253, feerate_per_kvbyte // 4)