This commit adds the ability to send/recv HTLC cancellation to the
commitment state machine. Previously this feature had been
unimplemented within the state machine, with only adds/settles working.
With this change, there’s now now no concept of “timing” out HTLC’s,
only the cancellation of HTLC’s which may be triggered for various
reasons.
This commit makes a large number of minor changes concerning API usage
within the deamon to match the latest version on the upstream btcsuite
libraries.
The major changes are the switch from wire.ShaHash to chainhash.Hash,
and that wire.NewMsgTx() now takes a paramter indicating the version of
the transaction to be created.
This commit converts the rearming two commitment spend functions to use
the lnwallet.Signer interface directly rather than manually manage
private keys during the signing process. This commit is in preparation
for implementation of fully automated revoked uncooperative closure
detection and retribution.
This commit modifies the channel state machine slightly to encode the
current state number using 30-bits of the sequence number within the
commitment transaction’s only input.
Such a modification reduces up the processing time required to punish
the counter party for breaching the contract established within the
channel by broadcasting an older revoked state.
This fixes#58 with a minor modification to what was originally
suggested.
This commit modifies the lnwallet code and related tests in order to
adhere to the recent field-name change to channeldb.OpenChannel.
Instead of having the field ‘TheirLNID’ which is the sha256 of the
node’s public key, we now instead use the public key directly in all
contexts.
This commit consists of a mass variable renaming to call the pkScript being executed for segwit outputs the `witnessScript` instead of `redeemScript`. The latter naming convention is generally considered to be reserved for the context of BIP 16 execution. With segwit to be deployed soon, we should be using the correct terminology uniformly through the codebase.
In addition some minor typos throughout the codebase has been fixed.
This commit modifies the prior funding workflow to account for fees
when creating the funding output. As a stop gap, the current fee for
the commitment transaction is now hard-coded at 5k satoshis. Once the
fee models are in place this should instead be some high multiple of
the current “average” fee rate within the network, continuing, the
proper fee should be adjusted from the commitment transaction has
outputs are added/removed.
This commit adds full persistence logic of the current lowest
un-revoked height within each commitment chain. The newly added
channeldb methods for record state transitions within both commitment
chains are now utilized. This un-settled HTLC state is now read upon
initialization, with the proper log entries inserted into the state
update log which reflect the garbage collected log right before the
restart.
A new set of tests have been added to exercise a few edge cases around
HTLC persistence to ensure the in-memory log is properly restored based
on the on-disk snapshot.
This commit performs a major refactor of the current wallet,
reservation, and channel code in order to call into a WalletController
implementation rather than directly into btcwallet.
The current set of wallets tests have been modified in order to test
against *all* registered WalletController implementations rather than
only btcwallet. As a result, all future WalletControllers primary need
to ensure that their implementation passes the current set of tests
(which will be expanded into the future), providing an easy path of
integration assurance.
Rather than directly holding the private keys throughout funding and
channel creation, the burden of securing keys has been shifted to the
specified WalletController and Signer interfaces. All signing is done
via the Signer interface rather than directly, increasing flexibility
dramatically.
During channel funding, rather than creating a txscript.Engine to
verify commitment signatures, regular ECDSA sig verification is now
used instead. This is faster and more efficient.
Finally certain fields/methods within ChannelReservation and
LightningChannel have been exposed publicly in order to restrict the
amount of modifications the prior tests needed to undergo in order to
support testing directly agains the WalletController interface.
This commit adds a basic test for cooperative channel closure. The
current test ensures correctness of the cooperative closure procedure
initiated by either the channel initiator, or the channel responder.
This commit patrons the state update logs properly within the channel
state machine. This change fixes a number of bugs caused by treating a
central log as two logically distinct logs. Rather than having a bit
indicating if the entry is incoming/outgoing, an entry is added to a
remote or local log depending on which modification method is used.
As a result the code is much easier to follow due to separation of
concerts.
Finally, when attempting to sign a new update with an exhausted
renovation window a distinct error is returned in order to allow higher
level callers to properly back-off and handle the protocol event.
This commit fixes a slight bug in the channel state machine’s code
executed when processing a revocation messages. With this commit after
processing a revocation, log entries which we should forward to the
downstream or upstream peer for settling/adding HTLC’s are now properly
returned.
The testa have also been updated to ensure to correct htlc’s are
returned “for forwarding”.
We no longer track HTLC’s by their r-hash within the log into the
index, as we may have multiple HTLC’s that can be redeemed by the same
pre-image. Instead we now use a separate index which is keyed by a
log-index.
Additionally, the SettleHTLC method now also returns the index of the
HTLC being settled which allows the remote party to quickly locate the
HTLC within their log.
This commit also introduces a few trace/debug log messages which will
likely be pruned in the near future
This commit finishes the initial draft of the commitment state machine.
A full re-write of the prior protocol which combines aspects of the
former ‘lnstate’ package has replaced the prior un-finished
stop-and-wait protocol.
This new protocol is designed to operate in an asynchronous environment
and to facilitate non-blocking batched and pipelined updates to the
committed channel states. The protocol is also de-synchronized meaning
that either side can propose new commitment states independent of the
actions of the other party.
The state machine implemented is very similar to that of c-lightning,
however we allow multiple unrevoked commentates in order to minimize
blocking, and also to reduce latency across several hops in a
bi-directional setting.
The current implementation consists of 3 main data structures: a
commitment chain which consist of unrevoked commitment transactions
(one for each side), and a (mostly) append-only log of HTLC updates
shared between both sides. New commitments proposed index into the log
denoting which updates they include, this allows both parties to
progress chains independent of one another. Revoked commitments, reduce
the length of the chain by one, and free up space within the revocation
window.
At this point only basic tests are in place for the state machine,
however more extensive testing infrastructure along with formal proofs
using PlusCall are planned.
