commit e23e0d6c6e6e419bd6c467478845e9e3403a1674
parent e18a3b5a3df7f465c16a619714ba916dbca894ca
Author: Janus <ysangkok@gmail.com>
Date: Tue, 25 Sep 2018 17:08:46 +0200
ln: avoid duplicated htlc filter code, support multiple htlcs better
Diffstat:
2 files changed, 53 insertions(+), 63 deletions(-)
diff --git a/electrum/lnhtlc.py b/electrum/lnhtlc.py
@@ -17,6 +17,7 @@ from .lnutil import sign_and_get_sig_string
from .lnutil import make_htlc_tx_with_open_channel, make_commitment, make_received_htlc, make_offered_htlc
from .lnutil import HTLC_TIMEOUT_WEIGHT, HTLC_SUCCESS_WEIGHT
from .lnutil import funding_output_script, LOCAL, REMOTE, HTLCOwner, make_closing_tx, make_outputs
+from .lnutil import ScriptHtlc
from .transaction import Transaction
@@ -265,19 +266,10 @@ class HTLCStateMachine(PrintError):
for_us = False
- feerate = self.pending_feerate(REMOTE)
-
htlcsigs = []
- for we_receive, htlcs in zip([True, False], [self.htlcs_in_remote, self.htlcs_in_local]):
- assert len(htlcs) <= 1
+ for we_receive, htlcs in zip([True, False], [self.included_htlcs(REMOTE, REMOTE), self.included_htlcs(REMOTE, LOCAL)]):
for htlc in htlcs:
- weight = HTLC_SUCCESS_WEIGHT if we_receive else HTLC_TIMEOUT_WEIGHT
- fee = feerate // 1000 * weight
- if htlc.amount_msat // 1000 < self.remote_config.dust_limit_sat + fee:
- print("value too small, skipping. htlc amt: {}, weight: {}, remote feerate {}, remote dust limit {}".format( htlc.amount_msat, weight, feerate, self.remote_config.dust_limit_sat))
- continue
- original_htlc_output_index = 0
- args = [self.remote_state.next_per_commitment_point, for_us, we_receive, htlc.amount_msat, htlc.cltv_expiry, htlc.payment_hash, pending_remote_commitment, original_htlc_output_index]
+ args = [self.remote_state.next_per_commitment_point, for_us, we_receive, pending_remote_commitment, htlc]
htlc_tx = make_htlc_tx_with_open_channel(self, *args)
sig = bfh(htlc_tx.sign_txin(0, their_remote_htlc_privkey))
htlc_sig = ecc.sig_string_from_der_sig(sig[:-1])
@@ -293,6 +285,8 @@ class HTLCStateMachine(PrintError):
if self.lnwatcher:
self.lnwatcher.process_new_offchain_ctx(self, pending_remote_commitment, ours=False)
+ htlcsigs.sort()
+
return sig_64, htlcsigs
def receive_new_commitment(self, sig, htlc_sigs):
@@ -322,27 +316,19 @@ class HTLCStateMachine(PrintError):
_, this_point, _ = self.points
- if len(pending_local_commitment.outputs()) >= 3:
- print("CHECKING HTLC SIGS")
- assert len(pending_local_commitment.outputs()) == 3
- if len(self.htlcs_in_remote) > 0:
- assert len(self.htlcs_in_remote) == 1
- we_receive = True
- htlc = self.htlcs_in_remote[0]
- elif len(self.htlcs_in_local) > 0:
- assert len(self.htlcs_in_local) == 1
- we_receive = False
- htlc = self.htlcs_in_local[0]
- else:
- assert False
-
- htlc_tx = make_htlc_tx_with_open_channel(self, this_point, True, we_receive, htlc.amount_msat, htlc.cltv_expiry, htlc.payment_hash, pending_local_commitment, 0)
- pre_hash = Hash(bfh(htlc_tx.serialize_preimage(0)))
- remote_htlc_pubkey = derive_pubkey(self.remote_config.htlc_basepoint.pubkey, this_point)
- if not ecc.verify_signature(remote_htlc_pubkey, htlc_sigs[0], pre_hash):
- raise Exception("failed verifying signature an HTLC tx spending from one of our commit tx'es HTLC outputs")
-
- # TODO check htlc in htlcs_in_local
+ for htlcs, we_receive in [(self.included_htlcs(LOCAL, REMOTE), True), (self.included_htlcs(LOCAL, LOCAL), False)]:
+ for htlc in htlcs:
+ htlc_tx = make_htlc_tx_with_open_channel(self, this_point, True, we_receive, pending_local_commitment, htlc)
+ pre_hash = Hash(bfh(htlc_tx.serialize_preimage(0)))
+ remote_htlc_pubkey = derive_pubkey(self.remote_config.htlc_basepoint.pubkey, this_point)
+ for idx, sig in enumerate(htlc_sigs):
+ if ecc.verify_signature(remote_htlc_pubkey, sig, pre_hash):
+ del htlc_sigs[idx]
+ break
+ else:
+ raise Exception(f'failed verifying HTLC signatures: {htlc}')
+ if len(htlc_sigs) != 0: # all sigs should have been popped above
+ raise Exception('failed verifying HTLC signatures: invalid amount of correct signatures')
for pending_fee in self.fee_mgr:
if pending_fee.is_proposed():
@@ -513,6 +499,13 @@ class HTLCStateMachine(PrintError):
unsettled_local + remote_settled - local_settled
return remote_msat, local_msat
+ def included_htlcs(self, subject, htlc_initiator):
+ feerate = self.pending_feerate(subject)
+ conf = self.remote_config if subject == REMOTE else self.local_config
+ weight = HTLC_SUCCESS_WEIGHT if subject != htlc_initiator else HTLC_TIMEOUT_WEIGHT
+ return filter(lambda htlc: htlc.amount_msat // 1000 - weight * (feerate // 1000) >= conf.dust_limit_sat,
+ self.htlcs_in_local if htlc_initiator == LOCAL else self.htlcs_in_remote)
+
@property
def pending_remote_commitment(self):
remote_msat, local_msat = self.amounts()
@@ -525,21 +518,15 @@ class HTLCStateMachine(PrintError):
local_htlc_pubkey = derive_pubkey(self.local_config.htlc_basepoint.pubkey, this_point)
local_revocation_pubkey = derive_blinded_pubkey(self.local_config.revocation_basepoint.pubkey, this_point)
- feerate = self.pending_feerate(REMOTE)
-
htlcs_in_local = []
- for htlc in self.htlcs_in_local:
- if htlc.amount_msat // 1000 - HTLC_SUCCESS_WEIGHT * (feerate // 1000) < self.remote_config.dust_limit_sat:
- continue
+ for htlc in self.included_htlcs(REMOTE, LOCAL):
htlcs_in_local.append(
- ( make_received_htlc(local_revocation_pubkey, local_htlc_pubkey, remote_htlc_pubkey, htlc.payment_hash, htlc.cltv_expiry), htlc.amount_msat))
+ ScriptHtlc( make_received_htlc(local_revocation_pubkey, local_htlc_pubkey, remote_htlc_pubkey, htlc.payment_hash, htlc.cltv_expiry), htlc))
htlcs_in_remote = []
- for htlc in self.htlcs_in_remote:
- if htlc.amount_msat // 1000 - HTLC_TIMEOUT_WEIGHT * (feerate // 1000) < self.remote_config.dust_limit_sat:
- continue
+ for htlc in self.included_htlcs(REMOTE, REMOTE):
htlcs_in_remote.append(
- ( make_offered_htlc(local_revocation_pubkey, local_htlc_pubkey, remote_htlc_pubkey, htlc.payment_hash), htlc.amount_msat))
+ ScriptHtlc( make_offered_htlc(local_revocation_pubkey, local_htlc_pubkey, remote_htlc_pubkey, htlc.payment_hash), htlc))
commit = self.make_commitment(self.remote_state.ctn + 1,
False, this_point,
@@ -575,18 +562,14 @@ class HTLCStateMachine(PrintError):
feerate = self.pending_feerate(LOCAL)
htlcs_in_local = []
- for htlc in self.htlcs_in_local:
- if htlc.amount_msat // 1000 - HTLC_TIMEOUT_WEIGHT * (feerate // 1000) < self.local_config.dust_limit_sat:
- continue
+ for htlc in self.included_htlcs(LOCAL, LOCAL):
htlcs_in_local.append(
- ( make_offered_htlc(remote_revocation_pubkey, remote_htlc_pubkey, local_htlc_pubkey, htlc.payment_hash), htlc.amount_msat))
+ ScriptHtlc( make_offered_htlc(remote_revocation_pubkey, remote_htlc_pubkey, local_htlc_pubkey, htlc.payment_hash), htlc))
htlcs_in_remote = []
- for htlc in self.htlcs_in_remote:
- if htlc.amount_msat // 1000 - HTLC_SUCCESS_WEIGHT * (feerate // 1000) < self.local_config.dust_limit_sat:
- continue
+ for htlc in self.included_htlcs(LOCAL, REMOTE):
htlcs_in_remote.append(
- ( make_received_htlc(remote_revocation_pubkey, remote_htlc_pubkey, local_htlc_pubkey, htlc.payment_hash, htlc.cltv_expiry), htlc.amount_msat))
+ ScriptHtlc( make_received_htlc(remote_revocation_pubkey, remote_htlc_pubkey, local_htlc_pubkey, htlc.payment_hash, htlc.cltv_expiry), htlc))
commit = self.make_commitment(self.local_state.ctn + 1,
True, this_point,
diff --git a/electrum/lnutil.py b/electrum/lnutil.py
@@ -25,6 +25,8 @@ LocalState = namedtuple("LocalState", ["ctn", "per_commitment_secret_seed", "amo
ChannelConstraints = namedtuple("ChannelConstraints", ["capacity", "is_initiator", "funding_txn_minimum_depth"])
#OpenChannel = namedtuple("OpenChannel", ["channel_id", "short_channel_id", "funding_outpoint", "local_config", "remote_config", "remote_state", "local_state", "constraints", "node_id"])
+ScriptHtlc = namedtuple('ScriptHtlc', ['redeem_script', 'htlc'])
+
class Outpoint(NamedTuple("Outpoint", [('txid', str), ('output_index', int)])):
def to_str(self):
return "{}:{}".format(self.txid, self.output_index)
@@ -235,7 +237,8 @@ def make_received_htlc(revocation_pubkey, remote_htlcpubkey, local_htlcpubkey, p
+ bitcoin.add_number_to_script(cltv_expiry) \
+ bytes([opcodes.OP_CLTV, opcodes.OP_DROP, opcodes.OP_CHECKSIG, opcodes.OP_ENDIF, opcodes.OP_ENDIF])
-def make_htlc_tx_with_open_channel(chan, pcp, for_us, we_receive, amount_msat, cltv_expiry, payment_hash, commit, original_htlc_output_index):
+def make_htlc_tx_with_open_channel(chan, pcp, for_us, we_receive, commit, htlc):
+ amount_msat, cltv_expiry, payment_hash = htlc.amount_msat, htlc.cltv_expiry, htlc.payment_hash
conf = chan.local_config if for_us else chan.remote_config
other_conf = chan.local_config if not for_us else chan.remote_config
@@ -258,8 +261,9 @@ def make_htlc_tx_with_open_channel(chan, pcp, for_us, we_receive, amount_msat, c
preimage_script = make_received_htlc(other_revocation_pubkey, other_htlc_pubkey, htlc_pubkey, payment_hash, cltv_expiry)
else:
preimage_script = make_offered_htlc(other_revocation_pubkey, other_htlc_pubkey, htlc_pubkey, payment_hash)
+ output_idx = commit.htlc_output_indices[htlc.payment_hash]
htlc_tx_inputs = make_htlc_tx_inputs(
- commit.txid(), commit.htlc_output_indices[original_htlc_output_index],
+ commit.txid(), output_idx,
revocationpubkey=revocation_pubkey,
local_delayedpubkey=delayedpubkey,
amount_msat=amount_msat,
@@ -290,20 +294,21 @@ def make_funding_input(local_funding_pubkey: bytes, remote_funding_pubkey: bytes
return c_input, payments
def make_outputs(fee_msat: int, we_pay_fee: bool, local_amount: int, remote_amount: int,
- local_tupl, remote_tupl, htlcs: List[Tuple[bytes, int]], dust_limit_sat: int) -> Tuple[List[TxOutput], List[TxOutput]]:
+ local_tupl, remote_tupl, htlcs: List[ScriptHtlc], dust_limit_sat: int) -> Tuple[List[TxOutput], List[TxOutput]]:
to_local_amt = local_amount - (fee_msat if we_pay_fee else 0)
to_local = TxOutput(*local_tupl, to_local_amt // 1000)
to_remote_amt = remote_amount - (fee_msat if not we_pay_fee else 0)
to_remote = TxOutput(*remote_tupl, to_remote_amt // 1000)
- c_outputs = [to_local, to_remote]
- for script, msat_amount in htlcs:
- c_outputs += [TxOutput(bitcoin.TYPE_ADDRESS,
+ non_htlc_outputs = [to_local, to_remote]
+ htlc_outputs = []
+ for script, htlc in htlcs:
+ htlc_outputs.append(TxOutput(bitcoin.TYPE_ADDRESS,
bitcoin.redeem_script_to_address('p2wsh', bh2u(script)),
- msat_amount // 1000)]
+ htlc.amount_msat // 1000))
# trim outputs
- c_outputs_filtered = list(filter(lambda x:x[2]>= dust_limit_sat, c_outputs))
- return c_outputs, c_outputs_filtered
+ c_outputs_filtered = list(filter(lambda x: x.value >= dust_limit_sat, non_htlc_outputs + htlc_outputs))
+ return htlc_outputs, c_outputs_filtered
def make_commitment(ctn, local_funding_pubkey, remote_funding_pubkey,
@@ -331,19 +336,21 @@ def make_commitment(ctn, local_funding_pubkey, remote_funding_pubkey,
fee = fee // 1000 * 1000
we_pay_fee = for_us == we_are_initiator
- c_outputs, c_outputs_filtered = make_outputs(fee, we_pay_fee, local_amount, remote_amount,
+ htlc_outputs, c_outputs_filtered = make_outputs(fee, we_pay_fee, local_amount, remote_amount,
(bitcoin.TYPE_ADDRESS, local_address), (bitcoin.TYPE_ADDRESS, remote_address), htlcs, dust_limit_sat)
- assert sum(x[2] for x in c_outputs) <= funding_sat
+ assert sum(x.value for x in c_outputs_filtered) <= funding_sat
# create commitment tx
tx = Transaction.from_io(c_inputs, c_outputs_filtered, locktime=locktime, version=2)
tx.htlc_output_indices = {}
- for idx, output in enumerate(c_outputs):
+ assert len(htlcs) == len(htlc_outputs)
+ for script_htlc, output in zip(htlcs, htlc_outputs):
if output in tx.outputs():
# minus the first two outputs (to_local, to_remote)
- tx.htlc_output_indices[idx - 2] = tx.outputs().index(output)
+ assert script_htlc.htlc.payment_hash not in tx.htlc_output_indices
+ tx.htlc_output_indices[script_htlc.htlc.payment_hash] = tx.outputs().index(output)
return tx
