commit 944e4f0ba0b6bbfb64c802a2b80515b27ded6713
parent fdf8d8609b632b6a3bf4202656e528bcf375ad2c
Author: SomberNight <somber.night@protonmail.com>
Date: Fri, 2 Aug 2019 18:04:13 +0200
implement data_loss_protect
so that we can spend their_ctx_to_remote even when we lost our state
but have an old backup
Diffstat:
3 files changed, 46 insertions(+), 10 deletions(-)
diff --git a/electrum/lnchannel.py b/electrum/lnchannel.py
@@ -65,6 +65,8 @@ class ChannelJsonEncoder(json.JSONEncoder):
RevokeAndAck = namedtuple("RevokeAndAck", ["per_commitment_secret", "next_per_commitment_point"])
+class RemoteCtnTooFarInFuture(Exception): pass
+
def decodeAll(d, local):
for k, v in d.items():
@@ -85,10 +87,10 @@ def htlcsum(htlcs):
# following two functions are used because json
# doesn't store int keys and byte string values
-def str_bytes_dict_from_save(x):
+def str_bytes_dict_from_save(x) -> Dict[int, bytes]:
return {int(k): bfh(v) for k,v in x.items()}
-def str_bytes_dict_to_save(x):
+def str_bytes_dict_to_save(x) -> Dict[str, str]:
return {str(k): bh2u(v) for k, v in x.items()}
@@ -132,6 +134,7 @@ class Channel(Logger):
self.short_channel_id_predicted = self.short_channel_id
self.onion_keys = str_bytes_dict_from_save(state.get('onion_keys', {}))
self.force_closed = state.get('force_closed')
+ self.data_loss_protect_remote_pcp = str_bytes_dict_from_save(state.get('data_loss_protect_remote_pcp', {}))
log = state.get('log')
self.hm = HTLCManager(local_ctn=self.config[LOCAL].ctn,
@@ -507,11 +510,12 @@ class Channel(Logger):
fee_for_htlc = lambda htlc: htlc.amount_msat // 1000 - (weight * feerate // 1000)
return list(filter(lambda htlc: fee_for_htlc(htlc) >= conf.dust_limit_sat, htlcs))
- def get_secret_and_point(self, subject, ctn):
+ def get_secret_and_point(self, subject, ctn) -> Tuple[Optional[bytes], bytes]:
assert type(subject) is HTLCOwner
offset = ctn - self.get_current_ctn(subject)
if subject == REMOTE:
- assert offset <= 1, offset
+ if offset > 1:
+ raise RemoteCtnTooFarInFuture(f"offset: {offset}")
conf = self.config[REMOTE]
if offset == 1:
secret = None
@@ -621,6 +625,7 @@ class Channel(Logger):
"log": self.hm.to_save(),
"onion_keys": str_bytes_dict_to_save(self.onion_keys),
"force_closed": self.force_closed,
+ "data_loss_protect_remote_pcp": str_bytes_dict_to_save(self.data_loss_protect_remote_pcp),
}
return to_save
diff --git a/electrum/lnpeer.py b/electrum/lnpeer.py
@@ -30,7 +30,7 @@ from .logging import Logger
from .lnonion import (new_onion_packet, decode_onion_error, OnionFailureCode, calc_hops_data_for_payment,
process_onion_packet, OnionPacket, construct_onion_error, OnionRoutingFailureMessage,
ProcessedOnionPacket)
-from .lnchannel import Channel, RevokeAndAck, htlcsum
+from .lnchannel import Channel, RevokeAndAck, htlcsum, RemoteCtnTooFarInFuture
from .lnutil import (Outpoint, LocalConfig, RECEIVED, UpdateAddHtlc,
RemoteConfig, OnlyPubkeyKeypair, ChannelConstraints, RevocationStore,
funding_output_script, get_per_commitment_secret_from_seed,
@@ -720,7 +720,8 @@ class Peer(Logger):
latest_remote_ctn = chan.hm.ctn_latest(REMOTE)
next_remote_ctn = latest_remote_ctn + 1
# send message
- if self.localfeatures & LnLocalFeatures.OPTION_DATA_LOSS_PROTECT_OPT:
+ dlp_enabled = self.localfeatures & LnLocalFeatures.OPTION_DATA_LOSS_PROTECT_OPT
+ if dlp_enabled:
if oldest_unrevoked_remote_ctn == 0:
last_rev_secret = 0
else:
@@ -746,6 +747,8 @@ class Peer(Logger):
chan.set_state('OPENING')
their_next_local_ctn = int.from_bytes(channel_reestablish_msg["next_local_commitment_number"], 'big')
their_oldest_unrevoked_remote_ctn = int.from_bytes(channel_reestablish_msg["next_remote_revocation_number"], 'big')
+ their_local_pcp = channel_reestablish_msg.get("my_current_per_commitment_point")
+ their_claim_of_our_last_per_commitment_secret = channel_reestablish_msg.get("your_last_per_commitment_secret")
should_close_we_are_ahead = False
should_close_they_are_ahead = False
@@ -786,9 +789,34 @@ class Peer(Logger):
should_close_we_are_ahead = True
else:
should_close_they_are_ahead = True
-
- # TODO option_data_loss_protect
-
+ # option_data_loss_protect
+ def are_datalossprotect_fields_valid() -> bool:
+ if their_local_pcp is None or their_claim_of_our_last_per_commitment_secret is None:
+ # if DLP was enabled, absence of fields is not OK
+ return not dlp_enabled
+ our_pcs, __ = chan.get_secret_and_point(LOCAL, their_oldest_unrevoked_remote_ctn - 1)
+ if our_pcs != their_claim_of_our_last_per_commitment_secret:
+ self.logger.error(f"channel_reestablish: (DLP) local PCS mismatch: {bh2u(our_pcs)} != {bh2u(their_claim_of_our_last_per_commitment_secret)}")
+ return False
+ try:
+ __, our_remote_pcp = chan.get_secret_and_point(REMOTE, their_next_local_ctn - 1)
+ except RemoteCtnTooFarInFuture:
+ pass
+ else:
+ if our_remote_pcp != their_local_pcp:
+ self.logger.error(f"channel_reestablish: (DLP) remote PCP mismatch: {bh2u(our_remote_pcp)} != {bh2u(their_local_pcp)}")
+ return False
+ return True
+
+ if not are_datalossprotect_fields_valid():
+ self.logger.error(f"channel_reestablish: data loss protect fields invalid.")
+ # TODO should we force-close?
+ return
+ else:
+ if dlp_enabled and should_close_they_are_ahead:
+ self.logger.warning(f"channel_reestablish: remote is ahead of us! luckily DLP is enabled. remote PCP: {bh2u(their_local_pcp)}")
+ chan.data_loss_protect_remote_pcp[their_next_local_ctn - 1] = their_local_pcp
+ self.lnworker.save_channel(chan)
if should_close_they_are_ahead:
self.logger.warning(f"channel_reestablish: remote is ahead of us! trying to get them to force-close.")
self.try_to_get_remote_to_force_close_with_their_latest(chan_id)
diff --git a/electrum/lnsweep.py b/electrum/lnsweep.py
@@ -245,7 +245,7 @@ def create_sweeptxs_for_our_ctx(chan: 'Channel', ctx: Transaction, ctn: int,
create_txns_for_htlc(htlc, is_received_htlc=True)
return txs
-def analyze_ctx(chan, ctx):
+def analyze_ctx(chan: 'Channel', ctx: Transaction):
# note: the remote sometimes has two valid non-revoked commitment transactions,
# either of which could be broadcast (their_conf.ctn, their_conf.ctn+1)
our_conf, their_conf = get_ordered_channel_configs(chan=chan, for_us=True)
@@ -265,6 +265,9 @@ def analyze_ctx(chan, ctx):
their_pcp = ecc.ECPrivkey(per_commitment_secret).get_public_key_bytes(compressed=True)
is_revocation = True
#_logger.info(f'tx for revoked: {list(txs.keys())}')
+ elif ctn in chan.data_loss_protect_remote_pcp:
+ their_pcp = chan.data_loss_protect_remote_pcp[ctn]
+ is_revocation = False
else:
return
return ctn, their_pcp, is_revocation, per_commitment_secret
