redeem htlc outputs of our local commitment transaction back to wallet
This commit is contained in:
Janus
@@ -3,7 +3,7 @@ from collections import namedtuple, defaultdict
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import binascii
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import json
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from enum import Enum, auto
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from typing import Optional, Mapping, List
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from typing import Optional, Dict, List, Tuple
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from .util import bfh, PrintError, bh2u
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from .bitcoin import Hash, TYPE_SCRIPT, TYPE_ADDRESS
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@@ -14,7 +14,7 @@ from .lnutil import Outpoint, LocalConfig, RemoteConfig, Keypair, OnlyPubkeyKeyp
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from .lnutil import get_per_commitment_secret_from_seed
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from .lnutil import make_commitment_output_to_remote_address, make_commitment_output_to_local_witness_script
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from .lnutil import secret_to_pubkey, derive_privkey, derive_pubkey, derive_blinded_pubkey, derive_blinded_privkey
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from .lnutil import sign_and_get_sig_string
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from .lnutil import sign_and_get_sig_string, privkey_to_pubkey, make_htlc_tx_witness
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from .lnutil import make_htlc_tx_with_open_channel, make_commitment, make_received_htlc, make_offered_htlc
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from .lnutil import HTLC_TIMEOUT_WEIGHT, HTLC_SUCCESS_WEIGHT
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from .lnutil import funding_output_script, LOCAL, REMOTE, HTLCOwner, make_closing_tx, make_outputs
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@@ -129,8 +129,8 @@ class Channel(PrintError):
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self.remote_commitment_to_be_revoked = Transaction(state["remote_commitment_to_be_revoked"])
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template = lambda: {
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'adds': {}, # type: Mapping[HTLC_ID, UpdateAddHtlc]
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'settles': [], # type: List[HTLC_ID]
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'adds': {}, # Dict[HTLC_ID, UpdateAddHtlc]
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'settles': [], # List[HTLC_ID]
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}
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self.log = {LOCAL: template(), REMOTE: template()}
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for strname, subject in [('remote_log', REMOTE), ('local_log', LOCAL)]:
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@@ -244,7 +244,7 @@ class Channel(PrintError):
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for we_receive, htlcs in zip([True, False], [self.included_htlcs(REMOTE, REMOTE), self.included_htlcs(REMOTE, LOCAL)]):
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for htlc in htlcs:
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args = [self.config[REMOTE].next_per_commitment_point, for_us, we_receive, pending_remote_commitment, htlc]
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htlc_tx = make_htlc_tx_with_open_channel(self, *args)
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_script, htlc_tx = make_htlc_tx_with_open_channel(self, *args)
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sig = bfh(htlc_tx.sign_txin(0, their_remote_htlc_privkey))
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htlc_sig = ecc.sig_string_from_der_sig(sig[:-1])
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htlcsigs.append((pending_remote_commitment.htlc_output_indices[htlc.payment_hash], htlc_sig))
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@@ -286,22 +286,20 @@ class Channel(PrintError):
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if not ecc.verify_signature(self.config[REMOTE].multisig_key.pubkey, sig, pre_hash):
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raise Exception('failed verifying signature of our updated commitment transaction: ' + bh2u(sig) + ' preimage is ' + preimage_hex)
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_, this_point, _ = self.points
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htlc_sigs_string = b''.join(htlc_sigs)
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htlc_sigs = htlc_sigs[:] # copy cause we will delete now
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for htlcs, we_receive in [(self.included_htlcs(LOCAL, REMOTE), True), (self.included_htlcs(LOCAL, LOCAL), False)]:
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for htlc in htlcs:
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htlc_tx = make_htlc_tx_with_open_channel(self, this_point, True, we_receive, pending_local_commitment, htlc)
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pre_hash = Hash(bfh(htlc_tx.serialize_preimage(0)))
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remote_htlc_pubkey = derive_pubkey(self.config[REMOTE].htlc_basepoint.pubkey, this_point)
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for idx, sig in enumerate(htlc_sigs):
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if ecc.verify_signature(remote_htlc_pubkey, sig, pre_hash):
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del htlc_sigs[idx]
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break
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else:
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raise Exception(f'failed verifying HTLC signatures: {htlc}')
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idx = self.verify_htlc(htlc, htlc_sigs, we_receive)
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del htlc_sigs[idx]
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if len(htlc_sigs) != 0: # all sigs should have been popped above
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raise Exception('failed verifying HTLC signatures: invalid amount of correct signatures')
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self.config[LOCAL]=self.config[LOCAL]._replace(
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current_commitment_signature=sig,
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current_htlc_signatures=htlc_sigs_string)
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for pending_fee in self.fee_mgr:
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if not self.constraints.is_initiator:
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pending_fee[FUNDEE_SIGNED] = True
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@@ -310,6 +308,16 @@ class Channel(PrintError):
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self.process_new_offchain_ctx(pending_local_commitment, ours=True)
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def verify_htlc(self, htlc, htlc_sigs, we_receive):
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_, this_point, _ = self.points
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_script, htlc_tx = make_htlc_tx_with_open_channel(self, this_point, True, we_receive, self.pending_local_commitment, htlc)
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pre_hash = Hash(bfh(htlc_tx.serialize_preimage(0)))
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remote_htlc_pubkey = derive_pubkey(self.config[REMOTE].htlc_basepoint.pubkey, this_point)
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for idx, sig in enumerate(htlc_sigs):
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if ecc.verify_signature(remote_htlc_pubkey, sig, pre_hash):
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return idx
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else:
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raise Exception(f'failed verifying HTLC signatures: {htlc}')
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def revoke_current_commitment(self):
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"""
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@@ -372,12 +380,14 @@ class Channel(PrintError):
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our_per_commitment_secret = get_per_commitment_secret_from_seed(
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self.config[LOCAL].per_commitment_secret_seed, RevocationStore.START_INDEX - ctn)
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our_cur_pcp = ecc.ECPrivkey(our_per_commitment_secret).get_public_key_bytes(compressed=True)
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encumbered_sweeptx = maybe_create_sweeptx_for_our_ctx_to_local(self, ctx, our_cur_pcp, self.sweep_address)
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encumbered_sweeptxs = create_sweeptxs_for_our_ctx(self, ctx, our_cur_pcp, self.sweep_address)
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else:
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their_cur_pcp = self.config[REMOTE].next_per_commitment_point
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encumbered_sweeptx = maybe_create_sweeptx_for_their_ctx_to_remote(self, ctx, their_cur_pcp, self.sweep_address)
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if encumbered_sweeptx:
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self.lnwatcher.add_sweep_tx(outpoint, ctx.txid(), encumbered_sweeptx.to_json())
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encumbered_sweeptxs = [(None, maybe_create_sweeptx_for_their_ctx_to_remote(self, ctx, their_cur_pcp, self.sweep_address))]
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for prev_txid, encumbered_tx in encumbered_sweeptxs:
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if prev_txid is None:
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prev_txid = ctx.txid()
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self.lnwatcher.add_sweep_tx(outpoint, prev_txid, encumbered_tx.to_json())
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def process_new_revocation_secret(self, per_commitment_secret: bytes):
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if not self.lnwatcher:
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@@ -739,7 +749,7 @@ def maybe_create_sweeptx_for_their_ctx_to_remote(chan, ctx, their_pcp: bytes,
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ctx=ctx,
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output_idx=output_idx,
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our_payment_privkey=our_payment_privkey)
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return EncumberedTransaction(sweep_tx, csv_delay=0)
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return EncumberedTransaction('their_ctx_to_remote', sweep_tx, csv_delay=0, cltv_expiry=0)
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def maybe_create_sweeptx_for_their_ctx_to_local(chan, ctx, per_commitment_secret: bytes,
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@@ -766,11 +776,11 @@ def maybe_create_sweeptx_for_their_ctx_to_local(chan, ctx, per_commitment_secret
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witness_script=witness_script,
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privkey=revocation_privkey,
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is_revocation=True)
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return EncumberedTransaction(sweep_tx, csv_delay=0)
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return EncumberedTransaction('their_ctx_to_local', sweep_tx, csv_delay=0, cltv_expiry=0)
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def maybe_create_sweeptx_for_our_ctx_to_local(chan, ctx, our_pcp: bytes,
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sweep_address) -> Optional[EncumberedTransaction]:
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def create_sweeptxs_for_our_ctx(chan, ctx, our_pcp: bytes, sweep_address) \
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-> List[Tuple[Optional[str],EncumberedTransaction]]:
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assert isinstance(our_pcp, bytes)
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delayed_bp_privkey = ecc.ECPrivkey(chan.config[LOCAL].delayed_basepoint.privkey)
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our_localdelayed_privkey = derive_privkey(delayed_bp_privkey.secret_scalar, our_pcp)
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@@ -782,21 +792,77 @@ def maybe_create_sweeptx_for_our_ctx_to_local(chan, ctx, our_pcp: bytes,
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witness_script = bh2u(make_commitment_output_to_local_witness_script(
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revocation_pubkey, to_self_delay, our_localdelayed_pubkey))
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to_local_address = redeem_script_to_address('p2wsh', witness_script)
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txs = []
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for output_idx, o in enumerate(ctx.outputs()):
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if o.type == TYPE_ADDRESS and o.address == to_local_address:
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sweep_tx = create_sweeptx_ctx_to_local(address=sweep_address,
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ctx=ctx,
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output_idx=output_idx,
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witness_script=witness_script,
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privkey=our_localdelayed_privkey.get_secret_bytes(),
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is_revocation=False,
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to_self_delay=to_self_delay)
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txs.append((None, EncumberedTransaction('our_ctx_to_local', sweep_tx, csv_delay=to_self_delay, cltv_expiry=0)))
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break
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else:
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return None
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sweep_tx = create_sweeptx_ctx_to_local(address=sweep_address,
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ctx=ctx,
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output_idx=output_idx,
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witness_script=witness_script,
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privkey=our_localdelayed_privkey.get_secret_bytes(),
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is_revocation=False,
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to_self_delay=to_self_delay)
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return EncumberedTransaction(sweep_tx, csv_delay=to_self_delay)
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# TODO htlc successes
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htlcs = list(chan.included_htlcs(LOCAL, LOCAL)) # timeouts
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for htlc in htlcs:
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witness_script, htlc_tx = make_htlc_tx_with_open_channel(
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chan,
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our_pcp,
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True, # for_us
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False, # we_receive
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ctx, htlc)
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data = chan.config[LOCAL].current_htlc_signatures
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htlc_sigs = [data[i:i+64] for i in range(0, len(data), 64)]
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idx = chan.verify_htlc(htlc, htlc_sigs, False)
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remote_htlc_sig = ecc.der_sig_from_sig_string(htlc_sigs[idx]) + b'\x01'
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remote_revocation_pubkey = derive_blinded_pubkey(chan.config[REMOTE].revocation_basepoint.pubkey, our_pcp)
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remote_htlc_pubkey = derive_pubkey(chan.config[REMOTE].htlc_basepoint.pubkey, our_pcp)
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local_htlc_key = derive_privkey(
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int.from_bytes(chan.config[LOCAL].htlc_basepoint.privkey, 'big'),
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our_pcp).to_bytes(32, 'big')
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program = make_offered_htlc(remote_revocation_pubkey, remote_htlc_pubkey, privkey_to_pubkey(local_htlc_key), htlc.payment_hash)
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local_htlc_sig = bfh(htlc_tx.sign_txin(0, local_htlc_key))
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htlc_tx.inputs()[0]['witness'] = bh2u(make_htlc_tx_witness(remote_htlc_sig, local_htlc_sig, b'', program))
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tx_size_bytes = 999 # TODO
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fee_per_kb = FEERATE_FALLBACK_STATIC_FEE
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fee = SimpleConfig.estimate_fee_for_feerate(fee_per_kb, tx_size_bytes)
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second_stage_outputs = [TxOutput(TYPE_ADDRESS, chan.sweep_address, htlc.amount_msat // 1000 - fee)]
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assert to_self_delay is not None
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second_stage_inputs = [{
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'scriptSig': '',
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'type': 'p2wsh',
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'signatures': [],
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'num_sig': 0,
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'prevout_n': 0,
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'prevout_hash': htlc_tx.txid(),
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'value': htlc_tx.outputs()[0].value,
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'coinbase': False,
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'preimage_script': bh2u(witness_script),
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'sequence': to_self_delay,
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}]
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tx = Transaction.from_io(second_stage_inputs, second_stage_outputs, version=2)
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local_delaykey = derive_privkey(
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int.from_bytes(chan.config[LOCAL].delayed_basepoint.privkey, 'big'),
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our_pcp).to_bytes(32, 'big')
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assert local_delaykey == our_localdelayed_privkey.get_secret_bytes()
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witness = construct_witness([bfh(tx.sign_txin(0, local_delaykey)), 0, witness_script])
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tx.inputs()[0]['witness'] = witness
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assert tx.is_complete()
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txs.append((htlc_tx.txid(), EncumberedTransaction(f'second_stage_to_wallet_{bh2u(htlc.payment_hash)}', tx, csv_delay=to_self_delay, cltv_expiry=0)))
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txs.append((ctx.txid(), EncumberedTransaction(f'our_ctx_htlc_tx_{bh2u(htlc.payment_hash)}', htlc_tx, csv_delay=0, cltv_expiry=htlc.cltv_expiry)))
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return txs
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def create_sweeptx_their_ctx_to_remote(address, ctx, output_idx: int, our_payment_privkey: ecc.ECPrivkey,
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fee_per_kb: int=None) -> Transaction:
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