This commit modifies the current core channel state machine in order to
may a step towards BOLT-0002 and BOLT-0003 compliance. In this change,
we abandon the prior revocation window, in favor of a fixed revocation
window of size two. The revocation window will be filled at the start
of the lifetime of the channel, and never extended from there until the
channel has been fully closed.
We now maintain two variables, the current un-revoked commitment point,
and the next commitment point to use when creating a new state. The
next commitment point must initially be inserted into the channel state
with the InitNextRevocation method.
A major difference between the prior revocation key handling is that
the remote party now instead sends us the _commitment point_ in
isolation, which we then use locally (with our revocation base point)
to create the next full revocation key for _their_ commitment
transaction.
This commit updates much of the state interaction within the
LightningChannel structure to account for the recent changes within the
chanenldb involving the OpenChannel struct, namely the introduction of
ChannelConfig and ChannelConstraints.
This commit introduce a new struct which acts as a companion struct to
the channel state machine struct. With the new commitment state
machine, we require a signature to be signed and validated for each
outstanding non-trimmed HTLC within the commitment state. As it’s
possible to have hundreds of HTLC’s on a given commitment transaction,
rather than perform all ECDSA operations in serial, we instead aim to
parallelize the computation with a worker pool of sign+verify workers.
The two primary methods of the sigPool are SubmitVerifyBatch and
SubmitSignBatch which allow a caller to trigger an asynchronous job
execution when creating or validating a new commitment state.
This commit updates the prior set of interface-level wallet tests to
exercise the new funding workflow, and also to switch to utilizing two
wallet instances throughout the tests. This allows us to abandon the
dependency on the bobNode struct.
This commit modifies the interface-level wallet integration tests to
spin up two distinct wallet instances, wiping them after each
successful test. This change paves the way for an upcoming change which
uses two live wallet instances, rather than mocking out most of the
other interaction.
This commit removes bobNode from the wallet’s funding interaction
tests. bobNode was originally created at a very early point in lnd’s
life time before any sort of back end chain access was hooked in. At
that time the integration tests were unable to run, but bobNode allowed
us to test a portion of the funding workflow given idealized inputs.
The tests will be modified in a later commit to eschew bobNode in favor
of just having two LightningWallet instances communicate with one
another.
This commit updates the engine that drives the reservation workflow to
utilize the new ChannelConfig and ChannelConstraint structs added in
prior commits. With this change, the internal reservation engine has
been modified to retain the prior dual funder workflow, but also be
able to properly manage and execute the new single funder workflow
defined in BOLT-0002.
This commit updates the channel reservation workflow in order to
properly implement the new funding workflow defined in BOLT-0002.
The workflow itself hasn’t changed significantly, but the contents of
the contributions of both sides have. The bulk of the fields within the
contribution of both sides has been boiled down into a pointer to the
ChannelConfig which houses all the data required to handle all states
of the channel, and commitment state machine.
For the two portions which are dictated by the other party, we now add
builder-like modifiers to allow specifying the constraints after the
initial portion of the workflow.
This commit modifies the Signer interface to reflect the new key
derivation defined within BOLT-0003. This entails removing the prior
PrivateTweak field all together in favor of two new fields: SingleTweak
and DoubleTweak.
These two fields are mutually exclusive. The SingleTweak field is now
required in order to sign all regular non-delay, and also must be used
to generate signatures for the localKey, or delayKey. The DoubleTweak
field is used to generate the private key that corresponds to the
revoked revocation key.
This commit updates the constants in size.go to include the weight of
the HTLC success and timeout transactions. These values are required in
order to properly compute the fee required for a particular HTLC
transaction. The fee will change depending on if the HTLC is incoming
or outgoing.
This commit adds a series of new functions that can be used to generate
the second level HTLC transactions, and also to claim the output
created by the transaction after a delay. The details of the scripts
and transaction format can be found in BOLT #3.
This commit updates all the pkScripts used within the commitment
transaction of the party that is on the reign side of an HTLC.
The major difference in these scripts as the prior generation’s is that
the claim action is now spared into a distinct transition. This clause
is guarded by a 2-of-2 multi-sig op code, which effecting creates an
off-chain covenant forcing the party claiming the transaction to incur
a delay before the funds can be swept.
This commit updates all the spendHtlcSpend* functions which are used to
spend each of the possible clauses within the HTLC contract placed on
the sender’s commitment transaction.
This commit updates the key derivation to match the derivation required
in order to construct and validate the commitment scheme that is used
within the draft specification of the Lightning Network. The new scheme
is very similar to the prior scheme aside from the following major
differences:
* Each key (not just the revocation key) now changes with each state.
* A commitment point (a component of the revocation key) is used to
randomize each key, and also generate new tweaked versions of the key.
* Base points are used along with the commitment point to generate
the keys for the commitment transaction.
* Before the remote party would send over the fully valid revocation
key. Now the remote party sends us a commitment point, which we then
use our local revocation base point to generate their revocation key.
This commit modifies the prior revocation root generation to a newer
version which is intended to allow for easy recovery of revocation
state. Rather than using the node’s keys (which we can’t count on NOT
to change), we instead now use the block hash as a salt. With this,
given the block hash prior to the one that funded the channel, and the
node’s identity key, we can reconstruct our revocation state.
This commit removes the RevocationDelay field from the HTLC struct as
with the latest commitment transaction scheme, it is no longer needed.
This is due to the fact the the delay is now observed when an on-chain
HTLC claim is attempted, rather than from Shane the HTLC itself has
been broadcast.
This commit adds some additional detail to the error message
encountered when the first byte of an act is an invalid handshake
version byte. This commit is meant to aide in tracking down a
re-occurring bug that has been encountered by early testers of the
software.
This commit adds a new method to the OpenChannel struct:
InsertNextRevocation. This functionality is required in order to
properly implement the new funding workflow and commitment transaction
state machine.
In the prior state machine, we utilized the “initial revocation window”
which would provide both sides with the necessary revocation keys that
they needed to create new commitment states. The version of the
commitment state machine within the specification has been simplified a
bit, and instead essentially incorporates a revocation window of 1. The
window is initially filled at the _opening_ of the commitment
transaction, then never extended, only “slid down” from there on.
This commit modifies the HTLC struct within the channeldb struct in
order to accommodate the additional storage that’s now required as a
result of the change to 2-of-2 HTLC covenant transactions within the
commitment transaction.
This commit is the next phase in a rather major overhaul of the
OpenChannel struct. With this commit we remove the old ours vs theirs
semantics with channel related state variables, and instead encapsulate
all local vs remote state into a ChannelConfig structure for each party
within the channel.
This commit introduces two new structs to the channeled package:
ChannelConfig and ChannelConstraints.
The ChannelConfig struct will eliminate many of the fields on the
OpenChannel struct (ours vs theirs), in favor of having a single config
for both sides (local and remote).
The ChannelConstraints struct will house the channel flow control and
HTLC policies for both sides. The fields of this struct will be used to
control the flow of HTLC’s within the channel. In the occasion that any
of these constraints are violated, either the connection, or the
channel entirely is to be failed.
This commit removes a database migration that was added to fix a bug
introduced within the first alpha release. This migration is no longer
needed as the underlying database scheme has changed since then.
This commit adds a new field to the CommitSig message: HtlcSigs. This
new field will house signatures for each of the HTLC’s on the newly
created commitment state. This addition allows us to implement the new
commitment transaction structure outlined within the specification
which modifies HTLC’s such that the claiming process is now a two-phase
process. The first state transitions an HTLC to the delay+claim state,
and the second state (after the delay has passed) allows the
broadcaster of the commitment transaction to sweep the HTLC’s.
Fixes#61.
This commit modifies the readElement and writeElement functions to add
the capability of reading/writing a slice of btcec.Signature. This new
case is required for the upcoming commit which will modify the
CommitSig message to include a field which houses signatures of reach
HTLC on the commitment transaction.
This commit adds the new set of single funder messages from the
specification. As a result, after this commit and a follow up, all of
our messages will directly line up with those that are detailed within
the specification.
The new set of funding messages are very similar to our prior ones,
aside from the main difference of the addition of several channel level
constraints that give nodes control over their exposure, throughput,
and other values.
This commit modifies the RevokeAndAck message in order to bring it more
in line with the current draft of the specification. The prior version
was based on a version that used a revocation hash for HTLC’s and a
revocation key for commitment outputs. The current commitment design
uses revocation keys uniformly throughout.
