tlnchannel: ctx output-ordering: identical htlcs are ordered by CLTV - electrum - Electrum Bitcoin wallet
HTML git clone https://git.parazyd.org/electrum
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---
DIR commit 44761972cb16a7cf09e38d2bcea1de7630f93138
DIR parent b1f606eaed10e6d6d3ead481301879ff065ee14a
HTML Author: SomberNight <somber.night@protonmail.com>
Date: Sun, 4 Aug 2019 04:55:23 +0200
lnchannel: ctx output-ordering: identical htlcs are ordered by CLTV
Diffstat:
M electrum/lnchannel.py | 1 +
M electrum/lnutil.py | 13 ++++++++++++-
M electrum/tests/test_lnutil.py | 2 +-
M electrum/transaction.py | 1 +
4 files changed, 15 insertions(+), 2 deletions(-)
---
DIR diff --git a/electrum/lnchannel.py b/electrum/lnchannel.py
t@@ -340,6 +340,7 @@ class Channel(Logger):
htlc_sigs = htlc_sigs[:] # copy cause we will delete now
for htlcs, we_receive in [(self.included_htlcs(LOCAL, SENT, ctn=next_local_ctn), False),
(self.included_htlcs(LOCAL, RECEIVED, ctn=next_local_ctn), True)]:
+ # FIXME this is quadratic. BOLT-02: "corresponding to the ordering of the commitment transaction"
for htlc in htlcs:
idx = self.verify_htlc(htlc, htlc_sigs, we_receive, pending_local_commitment)
del htlc_sigs[idx]
DIR diff --git a/electrum/lnutil.py b/electrum/lnutil.py
t@@ -93,7 +93,11 @@ class FeeUpdate(NamedTuple):
ChannelConstraints = namedtuple("ChannelConstraints", ["capacity", "is_initiator", "funding_txn_minimum_depth"])
-ScriptHtlc = namedtuple('ScriptHtlc', ['redeem_script', 'htlc'])
+
+class ScriptHtlc(NamedTuple):
+ redeem_script: bytes
+ htlc: 'UpdateAddHtlc'
+
class Outpoint(NamedTuple("Outpoint", [('txid', str), ('output_index', int)])):
def to_str(self):
t@@ -475,6 +479,13 @@ def make_commitment(ctn, local_funding_pubkey, remote_funding_pubkey,
remote_address = make_commitment_output_to_remote_address(remote_payment_pubkey)
# TODO trim htlc outputs here while also considering 2nd stage htlc transactions
+ # BOLT-03: "Transaction Input and Output Ordering
+ # Lexicographic ordering: see BIP69. In the case of identical HTLC outputs,
+ # the outputs are ordered in increasing cltv_expiry order."
+ # so we sort by cltv_expiry now; and the later BIP69-sort is assumed to be *stable*
+ htlcs = list(htlcs)
+ htlcs.sort(key=lambda x: x.htlc.cltv_expiry)
+
htlc_outputs, c_outputs_filtered = make_commitment_outputs(fees_per_participant, local_amount, remote_amount,
(bitcoin.TYPE_ADDRESS, local_address), (bitcoin.TYPE_ADDRESS, remote_address), htlcs, dust_limit_sat)
DIR diff --git a/electrum/tests/test_lnutil.py b/electrum/tests/test_lnutil.py
t@@ -495,7 +495,7 @@ class TestLNUtil(unittest.TestCase):
(1, 2000 * 1000),
(3, 3000 * 1000),
(4, 4000 * 1000)]:
- htlc_obj[num] = UpdateAddHtlc(amount_msat=msat, payment_hash=bitcoin.sha256(htlc_payment_preimage[num]), cltv_expiry=None, htlc_id=None, timestamp=0)
+ htlc_obj[num] = UpdateAddHtlc(amount_msat=msat, payment_hash=bitcoin.sha256(htlc_payment_preimage[num]), cltv_expiry=0, htlc_id=None, timestamp=0)
htlcs = [ScriptHtlc(htlc[x], htlc_obj[x]) for x in range(5)]
our_commit_tx = make_commitment(
DIR diff --git a/electrum/transaction.py b/electrum/transaction.py
t@@ -958,6 +958,7 @@ class Transaction:
txin['sequence'] = nSequence
def BIP69_sort(self, inputs=True, outputs=True):
+ # NOTE: other parts of the code rely on these sorts being *stable* sorts
if inputs:
self._inputs.sort(key = lambda i: (i['prevout_hash'], i['prevout_n']))
if outputs: