In this commit, we’ve added a new method to the channel state machine:
ActiveHtlcs. This method will allow callers to poll the state of the
channel to retrieve the set of HTLC’s active on *both* commitment
transactions.
In this commit, we modify the RevokeCurrentCommitment method to now
return the set of active HTLC’s. This will be used by callers in the
future to update other sub-systems when the set of HTLC’s on the
commitment changes, and can also be used on the RPC level to
synchronize systems level integration tests.
By returning a *TxWeightEstimator from each method, we now all callers
to chain the methods. This adds a bit of nice sugar when interacting
with the struct.
In this commit, we rename several of the existing WitnessType
definitions to be more descriptive than they were previously. We also
add a number of additional types which we need to handle scripts for,
but weren’t yet added before. Finally, we modify the
receiverHtlcSpendTimeout to optionally take an additional parameter to
set the locktime of the spending transaction accordingly. This final
modification allows the caller to specify that the lock time has
already been set on the main transaction.
To implement the BOLT 03 test vectors, a more powerful mockSigner is
required. The new version of mockSigner stores multiple keys and signs
the transaction outputs with the appropriate one.
This commit adds an additional check in GetUtxo that
tests for the nil-ness of the spend report returned by
the neutrino backend. Previously, a nil error and
spend report could be returned if the rescan did not
find the output at or above the start height. This
was observed to have cause a nil pointer dereference
when the returning line attempted to access the output.
This case is now handled by returning a distinct error
signaling that the output was not found.
This commit fixes a nasty bug that has been lingering within lnd, and
has been noticed due to the added retransmission logic. Before this
commit, upon a restart, if we had an active HTLC and received a new
commitment update, then we would re-forward ALL active HTLC’s. This
could at times lead to a nasty cycle:
* We re-forward an HTLC already processed.
* We then notice that the time-lock is out of date (retransmitted
HTLC), so we go to fail it.
* This is detected as a replay attack, so we send an
UpdateMalformedHTLC
* This second failure ends up creating a nil entry in the log,
leading to a panic.
* Remote party disconnects.
* Upon reconnect we send again as we need to retransmit the changes,
this goes on forever.
In order to fix this, we now ensure that we only forward HTLC’s that
have been newly locked in at this next state. With this, we now avoid
the loop described above, and also ensure that we don’t accidentally
attempt an HTLC replay attack on our selves.
Fixes#528.
Fixes#545.
In this commit, we add a new detailed error that’s to be returned
when/if the remote peer sends us an invalid commit signature. The new
error contains the transaction that we attempted to validate the
signature over, the sighs, and the state number. Returning this
additional information will serve to aide in debugging any
cross-implementation issues.
In this commit, add an additional return value to
CompleteCooperativeClose. We’ll now report to the caller our final
balance in the cooperative closure transaction. We report this as
depending on if we’re the initiator or not, our final balance may not
exactly match the balance we had in the last state.
This commit fixes a lingering bug that could at times cause
incompatibilities with other implementations when attempting a
cooperative channel close. Before this commit, we would use a pointer
to the funding txin everywhere. As a result, each time we made a new
state, or verified one, we would modify the sequence field of the main
txin of the commitment transaction. Due to this if we updated the
channel, then went to do a cooperative channel closure, the sequence of
the txin would still be set to the value we used as the state hint.
To remedy this, we now copy the txin each time when making the
commitment transaction, and also the cooperative closure transaction.
This avoids accidentally mutating the txin itself.
Fixes#502.
Previously, some methods on a LightningChannel like SettleHTLC and
FailHTLC would identify HTLCs by payment hash. This would not always
work correctly if there are multiple HTLCs with the same payment hash,
so instead we change these methods to identify HTLCs by their unique
identifiers instead.
Before this commit, during a reservation, we wouldn’t ever specify our
minHTL value. We don’t yet fully validate all channel constrains, but
doing this now serves to ensure that once those features are merged,
we’ll actually be setting a valid value for minHTLC.
In this commit, we extend the ProcessChanSyncMsg to detect a case where
we don’t have the necessary revocation window to send out a new commit.
This can arise if the remote party sends us a new state, but we haven’t
yet fully processed their FundingLocked message yet, so we would be
unable to create a new commitment state.
We fix this by enumerating each of our actions in the case of an error.
If we get ErrNoWindow, then this indicates that we can’t give the
remote party the commitment we would like to optimistically send over.
This isn’t an issue though, as in the next round, we’ll resynchronize
our state.
In this commit, we fix an existing bug that would cause issues within
the switch due to a value not being properly set. Before this commit we
would copy a byte array into a slice without first creating the
necessary capacity for that slice. To fix this, we’ll now ensure that
the blob has the proper capacity before copying over. Several tests
have been updated to always set a fake onion blob.
In this commit, we extend the initial check within SignNextCommitment
to bail out early if we don’t yet know the commitment point of the
remote party. This prevents a class of nil pointer panics if we attempt
to create a new state without yet having received the FundingLocked
message.
In this commit, we fix an existing bug within the EstimateFeePerWeight
method for the BtcdFeeEstimator. If the sat/byte value returned was too
low, then it was possible for us to end up with a zero valued
sat/weight. We correct this issue by detecting, and falling back to the
default fee rate if so.
In this commit, we fix an existing bug within our cooperative channel
closing transaction generation. Before this commit, we wouldn’t account
for the fee already allocated within the commitment transaction. As a
result, we would calculate the evaluated balance considering the fee
incorrectly. In this commit, we fix this by adding the commitment fee
to the balance of the initiator when crafting the closing transaction
In this commit, we fix an existing bug, as only the initiator needs to
validate any new fee updates. If the initiator sends an invalid fee,
then it will be rejected by the responder as it may put them below
their required reserve.
In this commit, we ensure that we reject any UpdateFee messages if
after applying the update, the initiator doesn’t have enough funds to
actually pay for the new commitment state.
A test has been added to exercise this new behavior.
In this commit, we update the retransmission logic to ensure that we
properly retransmit any sent UpdateFee messages as part of a state
transition. When creating a CommitDiff, if we have a pending fee
update, then we’ll add that to the set of logs updates. When restoring
the commit diff from disk, if we encounter an UpdateFee entry, then
we’ll apply that as waiting to be ACK’d and skip adding it as a log
entry.
A new test has been added to excessive this new behavior.
In this commit, we correct the BTC -> SAT conversion in
BtcdFeeEstimator. Previously, we use 10e8 instead of 1e8, causing us to
be off by an order of magnitude.
Adding 99 here didn’t really do anything but obfuscate when we were
trying to compute. We’re just using internet division to calculate 1%
of the channel capacity amount. This is the amount that the remote
party must remain above at all times.
In this commit, we add a new ResetState method to the channel state
machine which will reset the state of the channel to `channelOpen`. We
add this as before this commit, it was possible for a channel to shift
into the closing state, the closing negotiation be cancelled for
whatever reason, resulting the the channel held by the breachArbiter
unable to act to potential on-chain events.
In this commit, we fix an existing bug that had ramifications within
the operation of the lnd daemon. Before this commit, if the Stop()
method was called, then the closeObserver would exit as well. This
means that would no longer be watching for channel breaches on-chain,
and could miss either a cooperative channel closure or an actual
contract breach.
To fix this, we now introduce a new method to stop for closeObserver:
CancelObserver(). This should ONLY be called once either: the contract
has been fully settled on-chain, or whom ever is watching the relevant
signals has a newer version of the channel that it will watch instead.
In this commit, we modify CreateCloseProposal to no longer return the
same fee passed in. In the past, this method accepted a fee rat rather
than an absolute fee, and would return the computed absolute fee. Now
that the method takes the absolute fee directly, this is unnecessary.
In this commit, we modify the funding reservation workflow slightly to
allow callers to specify their own custom fee when initialization a
funding workflow. This gives power-users the ability to control exactly
how much in fees are paid for each new funding transaction.
In this commit, we extend the existing SendOutputs method on the
WalletController interface to be able to accept a custom fee. With
this, users are now able to specify their exact fee, allowing the
wallet to be fee estimation agnostic.
In this commit, we add a new implementation of the FeeEstimator
interface: the BtcdFeeEstimator. This implementation of the
FeeEstimator is backed by an active bcd instance. Any requests to query
for the current fee for a given confirmation target are proxied to this
active bcd instance.
In this commit, we extend the FeeEstimator methods to allow them to
return an error. This is required as most implementations aside from
the static fee estimator will want to be able to return errors to users
to indicate the inability to properly estimate fees.
In this commit, we move the FeeEstimator interface into a distinct file
as follow up commits will begin to flesh out the interface with
additional implementations.
Fix wrong calculation of overshot amount which causes coin select
function to go into infinite loop. If overshoot amount is calculated
by subtraction of totalSatoshis and amtNeeded than on the second
iteration of loop amtNeeded already include required fee inside, which
causes continuation of the coin selection loop.
In this commit, we add fully verification (other than checking the
commitment point matches after the fact) of the new optional fields
added to the lnwire.ChannelReestablish message. Two scenarios can
arise: we realize the remote party is on a prior state (and possibly
lost data), or we realize that *we* are on a prior state with the
remote party verifiably proving that they’re on a newer state.
In this commit we extend the set of fields populated within the
returned lnwire.ChannelReestablish to populate the optional data loss
fields. This entails included the commitment secret of the most
recently revoked remote commitment transaction and also our current
unrevoked commitment point.
In this commit, we update all the key derivation within the state
machine to account for the recent spec change which introduces a
distinct key for usages within all HTLC scripts. This change means that
the commitment payment and delay base points, are only required to be
online in the case that a party is forced to go to chain.
We introduce an additional local tweak to the keyring for the HTLC
tweak. Additionally, two new keys have been added: a local and a remote
HTLC key. Generation of sender/receiver HTLC scripts now use the local
and remote HTLC keys rather than the “payment” key for each party.
Finally, when creating/verifying signatures for second-level HTLC
transactions, we use these the distinct HTLC keys, rather than re-using
the payment keys.
In this commit, we modify the naming and comments of the routines that
create the sender/receiver HTLC scripts to denote that a set of
distinct keys are used. The scripts materially haven’t changed, but the
set of keys expected has.
In this commit we modify the primary InvoiceRegistry interface within
the package to instead return a direct value for LookupInvoice rather
than a pointer. This fixes an existing race condition wherein a caller
could modify or read the value of the returned invoice.
In this method we fix an existing deadlock within the unit tests when
running with the race condition detector on. We don’t need to grab the
mutex within the ProcessChanSyncMsg method as this should be the very
first method called when initializing the channel if a channel state
sync is needed.
In this commit we ensure that the channel is always able to exit by
adding a select statement with a quit case when we’re waiting on the
result of a job that was previously sent into the sigPool.
In this commit, we’ve added a set of unit tests to cover all enumerated
channel sync scenarios, including the case where both nodes deem that
they’re unable to synchronize properly.
In this commit we revert a prior commit
(5240953de02d281be694b2c87d151d6c7dce2cb5) which was added as a stop
gap before we added the proper state needed to recover from cases where
the commitment transactions of both chains had diverged slightly due to
asymmetric dust limits.
In this commit we do away with the existing availableLocalBalance
attribute and instead add a new, more accurate AvailableBalance method.
The new method will compute the available balance within the channel ,
assuming a new state was created at the instance the method was called.
This new method will now properly account for HTLC fees.
AvailableBalance is now called within AddHTLC in order to ensure we
don’t add any HTLC’s that are unable to be paid for from the PoV of the
fees on the commitment transaction.
We no longer need to manually pass in the channel delta to
AppendToRevocationLog (now called AdvanceCommitChainTail) as the
pointers on-disk will be updated atomically.
In this commit we update the RevokeCurrentCommitment method to properly
use the new database UpdateCommitment method along with properly
converting the in-memory commitment to its corresponding on-disk
format.
In this commit we complete the partially completed ReceiveReestablish
method and rename it to ProcessChanSyncMsg. The new version now
properly implements retransmission as defined within BOLT#2.
Additionally, we’ve added a new case which will optimistically try and
force a resynchronization of the commitment states if we detect we can
deliver a new commitment signature sooner than later after realizing
that we need to retransmit our last revocation message when we recevied
a new state transition.
This commit adds a new method: createCommitDiff. The method will, given
a newly constructed commitment, its signature, and HTLC signatures will
create a channeldb.CommitDiff. The CommitDiff created is to be stored
on disk, as it can be used in the case that the remote party didn’t
receive our CommitSig message and also forgot all the updates that we
queued with the update.
In this commit we complexly revamp the process of restoring all channel
state back into memory after a restart. We’ll now properly do the
following: restore the pending “dangling” commit of the remote party
into the in-memory commitment chain, re-populate all active HTLC’s back
into their respective update logs with the proper indexes/counters, and
properly restore the current commitment of the remote party back in
memory.
This commit adds a new method to the updateLog which will be used when
restoring the state of a channel from disk after a restart. This new
method will add an entry to the updateLog without incrementing either
of the counters as the HTLC already comes pre populated with its
historical index.
With these new fields, we’ll be able to properly reconstruct the log
state after a restart, as each commitment will now note both the
current HTLC and log index.
After addition of the retransmission logic in the channel link, we
should make the onion blobs persistant, the proper way to do this is
include the onion blobs in the payment descriptor rather than storing
them in the distinct struct in the channel link.
In this commit BOLT№2 retranmission logic for the channel link have
been added. Now if channel link have been initialised with the
'SyncState' field than it will send the lnwire.ChannelReestablish
message and will be waiting for receiving the same message from remote
side. Exchange of this message allow both sides understand which
updates they should exchange with each other in order sync their
states.
This commit changes the use of SigHash flags in the spend
transactions created in scrit_utils. Instead of always
using SigHashAll for the sweep signature, we instead use
the sighash flag specified by the passed sign descriptor.
Tis commit makes the btcwallet signer implementation use
signDesc.HashType instead of SigHashAll when signing
transactions. This will allow the creator of the transaction
to specify the sighash policy when creating the accompanying
sign descriptior.
In this commit, we fix an existing derivation from the commitment state
machine as defined within the specification. Before this commit, we
only kept a single counter which both HTLC adds and fails/settles would
share. This was valid in the prior pre-spec iteration of the state
machine. However in the current draft of the spec, only a distinct
counter for HTLCs are used throughout.
This would cause an incompatibility, as if we mixed adds and settles
during an exchange, then our counter values would differ with other
implementations. To remedy this, we now introduce a distinct HTLC
counter and index within the updateLog.
Each Add will increment both the log counter, and the HTLC counter.
Each Settle/Fail will only increment the log counter. Inbound
Settle/Fails will index into the HTLC index as to target the proper
HTLC. The PaymentDescriptor type has been extended with an additional
field (HltcIndex) which itself tracks the index of an incoming/outgoing
HTLC.
This moves the commitment transaction generation code out of
fetchCommitmentView into createCommitmentTx. Aside from being a pretty
clean logical split, this allows the transaction generation code to be
unit tested more effectively.
This commit fixes the TestChannelBalanceDustLimit unit test in
channel_test.go. The unit test does not account for the fees
required by adding an HTLC. As a result, Alice's balance according
to her local and remote commitment chains drops below 0 at certain
points. By using the correct fee, this is avoided.
The fee estimation for funding transactions now properly accounts for
different types of UTXOs spent, whereas previously it assumed all
inputs were spending native P2WKH outputs.
Use binary.Read/Write in functions to serialize and deserialize
channel close summary and HTLC boolean data, as well as in
methods to put and fetch channel funding info. Remove lnd
implementations of readBool and writeBool as they are no
longer needed. Also fix a few minor typos.
Use sort.Slice in SignNextCommitment function in lnwallet/channel.go,
as part of the move to use new language features. Remove
sortableSignBatch type wrapper for slice of signJobs since it is
no longer needed to sort jobs according to their output indices.
Also fix a few minor typos in channel.go and sigpool.go.
This commit fixes an existing bug where we attempted to re-use the same
commitTweak value when creating an HTLC resolution. Instead, we now
create the commit tweak value factoring the key that is to be used for
signing.
In this commit, we extend the help message for `newaddress`
to indicate which address types can be used when directly
funding channels. Additionally, we add some additional text
to the insufficient funding error to detail that we don't have
enough witness outputs.
This commit expands the existing TestForceClose test case to add an
HTLC (outgoing) to Alice’s commitment transaction before force closing.
We then ensure that both the pre-signed timeout transaction _and_ the
sign descriptor to sweep the second-level output are fully valid.
This commit fixes an existing bug within extractHtlcResolutions. The
prior code would use an index to assign the returned
OutgoingHtlcResolutions into a single slice. However, this is invalid
as there are two cases where an HTLC might be skipped: if it’s an
incoming HTLC, or if the HLTC itself is dust from the PoV of the
commitment chain.
To fix this, we now instead use append to add items to the slice. This
ensure that we don’t have any “empty” items in between fully populated
items.
This commit extracts the ending dust adherence test case from the
existing TestForceClose test case into a distinct test case. With this
modification, we now ensure that the two new tests are focused and test
a single scenario at at time.
This commit fixes a bug wherein we would use the incorrect csvDelay
when crafting HTLC resolutions after a unilateral channel closure.
Previously, we would always use the csvDelay of the local party, as in
the force close case that’s the correct value. However, a unilateral
channel closure instead requires the _remote_ delay.
This commit fixes an existing bug when crafting the HTLC resolution in
the face of a commitment broadcast. Previously, we we’re using the
localKey which is incorrect, as directly below we properly use the
delayKey when crafting the secondLevelHtlcScript to sign.
This commit adds a new field: MaturityDelay, to the
UnilateralCloseSummary struct. This new field will be required, in an
upcoming update as it’s needed in order to properly sweep the
second-level HTLC outputs after MaturityDelay blocks has passed since
confirmation.
This commit fixes a minor bug (that doesn’t affect anything atm) when
crafting the SignDesc for sweeping breached outputs. Previously, we
would take the p2wkh script and then p2wsh-ify that, placing that into
the SignDesc. This is incorrect as the p2wkh script is “injected” into
the sighash when signing, and thus doesn’t need another encoding layer.
This commit adds an additional return value to SettleHTLC in order to
make way for an upcoming change to modify the way bandwidth status from
the link to the switch is reported.
This commit removes the current active LocalAvailableBalance method
from the channel state machine itself. We still maintain the internal
availableLocalBalance method locally as this is used to ensure that we
don’t add an HTLC which puts our available balance below zero.
This commit also adds an incoming flag to
HtlcRetribution struct to allow the breach arbiter to
generate the appropriate witness based on the htlc's
directionality.
It also ensures that the size of the htlc retribution
slice is now determined by the size of the number of
htlcs present in the revoked snapshot, which fixes a
minor bug that could lead to nil pointer deferences.
This commit is a follow up to the prior commit, as since we reversed
the order of the pubkeys in the multi-sig scripts, then we also need to
reverse the order of the signatures that we use when attempting to
spend the funding output directly.
When creating the script for the funding output, we were reversing the
order of the public keys due to an incorrect assertion of the return
value of the bytes.Compare function. To fix this, we now flip the
order, allowing us to properly create channels as specified within the
specification.
This commit adds to methods to the ChannelReservation struct: one for
generating the channel constraints we require for the remote party, and
one for validating their desired constraints, and committing them to
our ChannelConfig.
With these two new methods, we can now begin to properly store and
adhere to the current set of channel flow control constraints.
This commit fixes an existing w.r.t the way that we constructed all
commitment transactions. We were computing the hash that the obfsucator
was derived form correctly, but we were using the first 6-bytes, rather
than the last 6 bytes.
We no longer attach the RPC client to the lnwallet logging instance as
it can generate a ton of spam in trace mode as it’ll dump the entire
hex encoded blocks, transactions, etc.
This commit fixes a bug within the HTLC construction and commitment
transaction construction that would result in HTLC _values_ within the
commitment transaction being off by a factor of 1000. This was due to
the fact that we failed to convert the amount of an HTLC, in mSAT, to
SAT before placing it as an output within the commitment transaction.
When attempt to locate the output index of a particular half, we use
the unconverted amount, meaning it was unnoticed.
This commit adds a new assertion within the TestSimpleAddSettleWorkflow
test to ensure that the HTLC is found within the commitment transaction
with the proper value in satoshi.
This commit updates the script we use to match the current
specification. The change is minor: we can say an extra byte by moving
the OP_CHECKSIG to the end of the script, and swapping the checks and
seqverify operations in the second clause. However, the witness remains
the same!
Note that this commit is temporary, and should be reverted once #231 is
merged. The reason we need to do this for now, is that we don’t
properly track the exact state of the remote party’s commitment. In
this test case, the resulting HTLC’s added are dust to one party, but
non-dust to another. So upon restart, the states (balance wise) has
diverged.
This commit fixes a lingering bug in the way the internal channel state
machine handled fee calculation. Previously, we would count the dust
HTLC’s that were trimmed towards the fee that the initiator paid. This
is invalid as otherwise, the initiator would always benefit from dust
HTLC’s. Instead, we now simply “donate” the dust HTLC’s to the miner in
the commitment transaction. This change puts us in compliance with
BOLT-0003.
This commit modifies the CommitSpendNoDelay script witness generation
function. We must modify this function as all non-delayed outputs now
also require a key derivation. The current default
signer.ComputeInputScript implementation is unable to directly look up
the public key required as it attempt to target the pub key using the
pkScript.
This commit modifies the closeObserver code to populate the signDesc in
the case we have a non-trimmed balance. Additionally, we now also add a
*wire.OutPoint field to the struct in order to allow receivers of the
message to construct a witness that can spend the newly created output
to their wallet.
This commit modifies the methods that transition the state of the
channel into an active closing state. With the new commitment design,
the delivery scripts are no longer pre-committed to the initial funding
messages. Instead, the scripts are sent at the instant that either side
decides to shutdown within the Shutdown message.
This commit adds a new companion struct: OutgoingHtlcResolution to the
commitment state machine. The purpose of this struct is the provide the
caller with the information necessary to sweep all outgoing HTLC’s in
the case of a broadcast up-to-date commitment transaction.
The HTLC resolutions allow a caller to sweep an outgoing HTLC into
their wallet after the absolute timeout of the HTLc has passed. This is
a two step process, with the first portion consisting of broadcasting
the HTLC timeout transaction itself, and the second portion consisting
of claiming the HTLC itself after a CSV delay.
This commit adds awareness of active HTLC outputs to the
BreachRetribution struct. Previously, in the case of a breach, the
struct was only populated with enough information to sweep the two
commitment outputs. With this commit, the struct now has enough
information to sweep _all_ outputs within the commitment transaction.
This commit updates the central fetchCommitmentView method to manage
and derive the necessary easy required to create new commitments due to
the new state machine design within the specification. Each state now
requires us to derive a number of keys for each commitment state:
localDelay, remoteDelay, localKey, remoteKey, the commitment point, and
finally the revocation key itself.
