In this commit, we begin to integrate the new channel funding package
into the existing codebase. With this set of changes, we'll no longer
construct and sign the funding transaction within this package, instead
delegating it to the new chanfunding package. We use the new
chanfunding.WalletAssembler to carry out all channel funding, providing
it with an implementation of all its interfaces backed by the wallet.
In this commit, we introduce a series of new abstractions for channel
funding. The end goal is to enable uses cases that construct the funding
transaction externally, eventually handing the funding outpoint to lnd.
An example of such a use case includes channel factories and external
channel funding using a hardware wallet.
We also add a new chanfunding.Assembler meant to allow external channel
funding in contexts similar to how channel factories
can be constructed. With this channel funder, we'll only obtain the
channel point and funding output from it, as this alone is enough to
carry out a funding flow as normal.
In this commit, we make an incremental change to move the existing coin
selection code into a new chanfunding package. In later commits, this
package will grow to serve all the lower level channel funding needs in
the daemon.
Instead of tracking local updates in a separate link variable, query
this state from the channel itself.
This commit also fixes the issue where the commit tx was not updated
anymore after a failed first attempt because the revocation window was
closed. Also those pending updates will be taken into account when the
remote party revokes.
Previously the channel method FullySynced was used to decide whether to
send a new commit sig message. However, it could happen that FullySynced
was false, but that we didn't owe a commitment signature. Instead we
were waiting on the other party to send us a signature. If that
happened, we'd send out an empty commit sig. This commit modifies the
condition that triggers a new commit sig and fixes this deviation from
the spec.
To facilitate the logging, this commit adds a new OweCommitment method.
For the logging, we only need to consider the remote perspective. In a
later commit, we'll also start using the local perspective to support
the decision to send another signature.
In this commit, we create a new chainfee package, that houses all fee
related functionality used within the codebase. The creation of this new
package furthers our long-term goal of extracting functionality from the
bloated `lnwallet` package into new distinct packages. Additionally,
this new packages resolves a class of import cycle that could arise if a
new package that was imported by something in `lnwallet` wanted to use
the existing fee related functions in the prior `lnwallet` package.
In this commit, we convert the existing `channeldb.ChannelType` type
into a _bit field_. This doesn't require us to change the current
serialization or interpretation or the type as it is, since all the
current defined values us a distinct bit. This PR lays the ground work
for any future changes that may introduce new channel types (like anchor
outputs), and also any changes that may modify the existing invariants
around channels (if we're the initiator, we always have the funding
transaction).
Without this, it was possible for a combination of our balance and max
fee allocation to result in a fee rate below the fee floor causing the
remote party to reject the update and close the channel.
In this commit, we use the recently added `chanvalidate` package to
verify channels once they have been confirmed in the funding manager. We
expose a new method on the `LightningWallet` struct: `ValidateChannels`
which calls the new shared 1st party verification code.
After the channel is fully confirmed in the funding manager, we'll now
use this newly exposed method to handle all validation. As a result, we
can remove the existing validation code in the funding manager, and rely
on the new code in isolation.
In this commit, we create a new `chanvalidate` package which it to house
all logic required for 1st and 3rd party channel verification. 1st party
verification occurs when we find a channel in the chain that is
allegedly ours, while 3rd party verification will occur when a peer
sends us a channel proof of a new channel.
In the scope of the recent CVE, we actually fully verified 3rd party
channels, but failed to also include those checks in our 1st party
verification code. In order to unify this logic, and prevent future
issues, in this PR we move to concentrate all validation logic into a
single function. Both 1st and 3rd party validation will then use this
function. Additionally, having all the logic in a single place makes it
easier to audit, and also write tests against.
In this commit, we move to make a full deep copy of the commitment
transaction in `getSignedCommitTx` to ensure that we don't mutate the
commitment on disk, possibly resulting in a "hot commitment".
In this commit, we consolidate the number of areas where we derive our
commitment keys. Before this commit, the `isOurCommitment` function in
the chain watcher used a custom routine to derive the expected
scripts/keys for our commitment at that height. With the recent changes,
we now have additional logic in `DeriveCommitmentKeys` that wasn't
copied over to this area. As a result, the prior logic would erroneously
detect if it was our commitment that had hit the chain or not.
In this commit, we remove the old custom code, and use
`DeriveCommitmentKeys` wihtin the chain watcher as well. This ensures
that we only need to maintain the key derivation code in a single place,
preventing future bugs of this nature.
In this commit, we update the brar logic in the channel state machine,
and also the brar itself to be aware of the new commitment format.
Similar to the unilateral close summary, we'll now blank out the
SingleTweak field in `NewBreachRetribution` if it's a tweakless
commitment. The brar will then use this to properly identify the
commitment type, to ensure we use the proper witness generation function
when we're handling our own breach.
In this commit, we update the funding workflow to be aware of the new
channel type that doesn't tweak the remote party's output within the
non-delay script on their commitment transaction. To do this, we now
allow the caller of `InnitChannelReservation` to signal if they want the
old or new (tweakless) commitment style.
The funding tests are also updated to test both funding variants, as
we'll still need to understand the legacy format for older nodes.
In this commit, we update the channel state machine to be aware of
tweakless commits. In several areas, we'll now check the channel's type
to see if it's `SingleFunderTweakless`. If so, then we'll opt to use the
remote party's non-delay based point directly in the script, skipping
any additional cryptographic operations. Along the way we move the
`validateCommitmentSanity` method to be defined _before_ it's used as is
cutomary within the codebase.
Notably, within the `NewUnilateralCloseSummary` method, we'll now _blank
out_ the `SingleTweak` value if the commitment is tweakless. This
indicates to callers the witness type they should map to, as the value
isn't needed at all any longer when sweeping a non-delay output.
We also update the signing+verification tests to also test that we're
able to properly generate a valid witness for the new tweakless
commitment format.
Instead of marking the database state when processing the channel
reestablishment message, we wait for the result of this processing to
arrive in the link, and mark it accordingly in the database here.
We do this move the logic determining whether we should force close the
channel or not, and what state to mark it in the DB, to the same place,
as these need to be consistent.
This commit converts the ErrCommitSyncLocalDataLoss error into a struct,
that also holds the received last unrevoked commit point from the remote
party.
Checks that we get ErrDoubleSpend as expected when publishing a
conflicting mempool transaction with the same fee as the existing one,
and that we can publish a replacement with a higher fee successfully.
error
Since btcwallet will return typed errors now, we can simplify the
matching logic in order to return ErrDoubleSpend.
In case a transaction cannot be published since it did not satisfy the
requirements for a valid replacement, return ErrDoubleSpend to indicate
it was not propagated.
The cache wasn't really serving a purpose as FetchInputInfo isn't known
to be a hot path. Also, with a planned addition of returning the
confirmation status of an output within FetchInputInfo in a later
commit, caching won't be useful as we'll have to go to disk anyway to
determine the confirmation status.
In this commit, we address an edge case that can happen a user rescans
w/ their seed, while retaining their existing `channel.db`. Once they
rescan, if they go to sign for a channel sweep for example, the
commitment key family (actually an account) may not yet have been
created, causing the signing attempt to fail.
We remedy this always creating the account if we go to sign, and the
account isn't found. The change has been structured to make this the
exception, so we'll avoid always needing to do 2 DB hits (check if
account exists, sign), each time we sign.
A new test has been added to exercise this behavior. If the diff from
the `signer.go` file is removed, then the test will fail.
This commit adds a SubtractFees option to the funding request, letting
the caller specify that the fees should be deducted from the funding
amount. This paves the way for letting the funding manager spend up to a
given amount when creating a channel, like the rest of the funds in the
wallet.
This makes the method independent of the ChannelContribution struct.
We also add a function closure to the return of selectCoinsAndChange,
that let is unlock the selected output in case of error.
In this commit, we fix an existing bug that would cause us to be unable
to derive the very first key in a key family if the wallet hadn't
already derived it in the past. This can happen if a user keeps their
same `channel.db`, but restores their wallet resulting in fresh
`wallet.db` state.
This is an existing issue due to the fact that we don't properly
distinguish between an empty key locator, and the very first key in a
`KeyFamily`: `(0, 0)`. Atm, `KeyLoactor{0, 0}.IsEmpty() == True`,
causing us to be unable to retrieve this key in certain cases since we
fall through and attempt address based derivation.
In order to remedy this, we add a new special case (until we upgrade
`KeyLoactor` formats, but needed for legacy reasons) to _try_ a regular
`KeyLoactor` based derivation if we fail to derive via address, and this
is an "empty" key loc. This has been tested in the field and shown to
work, with the one downside that in this "hot swap restoration" case,
we'll hit the database twice to derive the key.
In this commit, we fix a logic flaw in the testCreateSimpleTx test case
which emerged once we the bug fix for dust outputs landed. Before this
commit, we would erroneously fail during valid test execution.
In this commit we fix a hidden bug in the transaction creating logic
that was only manifested recently due to higher fees on Bitcoin's
mainnet. Before this commit, we would use the target fee rate to
determine if an output was dust or not. However, this is incorrect, as
instead the relay fee should be used as this matches the policy checks
widely deployed in Bitcoin full node today.
To fix this issue we now properly use the relay fee when computing dust.
This fixes the issue for the `EstimateFee` call, but the `SendOutputs`
call also has a similar issue. However, this must be fixed within
`btcwallet` itself, so it has been left out of this commit
Fixes#3217.
In this commit, we patch a small bug in the newly added raw tx hex field
for ListTransactions. We now ensure that we also set the raw tx hex
field for unconfirmed transactions.
In this commit, we fix a lingering TOOD statement in the channel arb.
Before this commitment, we would simply wipe our our local HTLC set of
the HTLC set that was on the remote commitment transaction on force
close. This was incorrect as if our commitment transaction had an HTLC
that the remote commitment didn't, then we would fail to cancel that
back, and cause both channels to time out on chain.
In order to remedy this, we introduce a new `HtlcSetKey` struct to track
all 3 possible in-flight set of HTLCs: ours, theirs, and their pending.
We also we start to tack on additional data to all the unilateral close
messages we send to subscribers. This new data is the CommitSet, or the
set of valid commitments at channel closure time. This new information
will be used by the channel arb in an upcoming commit to ensure it will
cancel back HTLCs in the case of split commitment state.
Finally, we start to thread through an optional *CommitSet to the
advanceState method. This additional information will give the channel
arb addition information it needs to ensure it properly cancels back
HTLCs that are about to time out or may time out depending on which
commitment is played.
Within the htlcswitch pakage, we modify the `SignNextCommitment` method
to return the new set of pending HTLCs for the remote party's commitment
transaction and `ReceiveRevocation` to return the latest set of
commitment transactions on the remote party's commitment as well. This
is a preparatory change which is part of a larger change to address a
lingering TODO in the cnct.
Additionally, rather than just send of the set of HTLCs after the we
revoke, we'll also send of the set of HTLCs after the remote party
revokes, and we create a pending commitment state for it.
Now that the success resolver preimage field is always populated by the
incoming contest resolver, preimage lookups earlier in the
process (channel and channel arbitrator) can mostly be removed.
This enables users to specify an external API for fee estimation.
The API is expected to return fees in the JSON format:
`{
fee_by_block_target: {
a: x,
b: y,
...
c: z
}
}`
where a, b, c are block targets and x, y, z are fees in sat/kb.
Note that a, b, c need not be contiguous.
In this commit, we add a new interface which will allow callers to drop
in an arbitrary Web API for fee estimation with an arbitrary
request/response schema.
Co-authored-by: Valentine Wallace <vwallace@protonmail.com>
In this commit, we modify the main `closeObserver` dispatch loop to only
look for the local force close if we didn't recover the channel. We do
this, as for a recovered channel, it isn't possible for us to force
close from a recovered channel.
In this commit, we modify the `ChanSyncMsg` to send an invalid
commitment secret in `ChanSyncMsg`. We do this in order to force the
remote party to force close off-chain, if we're restoring a channel from
scratch and we never had any state updates within the channel. We need
to do this, as otherwise the remote party will think we can resume as
they're able to verify their own commit secret for state zero.
The checks to determine whether the transaction broadcast failed due to
it already existing in the mempool/chain are no longer needed since the
underlying btcwallet PublishTransaction call will not return an error
when running into these cases.
In this commit, we update the `TestChanSyncFailure` method to pass given
the new behavior around updating borked channel states. In order to do
this, we add a new method to allow the test to clear an existing channel
state. This method may be of independent use in other areas in the
codebase in the future as well.
In this commit, we add a new test: `TestForceCloseBorkedState`. This
ensures that it isn't possible to update the channel state once a
channel has been marked as borked. This assumes that all calls to
`ForceClose` will also mark the channel as borked. This isn't the case
yet, so this test fails as is.
In this commit, we add a new `LastUnusedAddress` method to the
`WalletController` interface. Callers can use this new method to graph
the last unused address, which can be useful for UIs that want to
refresh the address, but not cause nearly unbounded address generation.
The implementation for `btcwallet` uses the existing `CurrentAddress`
method. We've also added a new integration tests to exercise the new
functionality.
In this commit, we set a default max HTLC in the forwarding
policies of newly open channels.
The ForwardingPolicy's MaxHTLC field (added in this commit)
will later be used to decide whether an HTLC satisfies our policy before
forwarding it.
To ensure the ForwardingPolicy's MaxHTLC default matches the max HTLC
advertised in the ChannelUpdate sent out for this channel, we also add
a MaxPendingAmount() function to the lnwallet.Channel.
In this commit, we modify the WitnessCache's
AddPreimage method to accept a variadic number
of preimages. This enables callers to batch
preimage writes in performance critical areas
of the codebase, e.g. the htlcswitch.
Additionally, we lift the computation of the
witnesses' keys outside of the db transaction.
This saves us from having to do hashing inside
and blocking other callers, and limits extraneous
blocking at the call site.
This commit is a step to split the lnwallet package. It puts the Input
interface and implementations in a separate package along with all their
dependencies from lnwallet.
To avoid more bugs slipping through where the logIndex is not set, we
panic to catch this. This was earlier done for Adds and the htlcCounter,
which did lead us to find the resulting retoration bug.
Earlier versions did not write the log index to disk for fee updates, so
they will be unset. To account for this we set them to to current update
log index.
This reverts commit 4aa52d267f000f84caf912c62fc14a5b8e7cacb5.
It turns out that the other implementations set values for this field
which aren't based on the actual capacity of the channel. As a result,
we'll no reject most of their channel offerings, since they may offer a
value of a max `uint64` or something else hard coded that's above the
size of the channel. As a result, we're reverting this check for now to
maintain proper compatibility.
In this commit, we ensure that if a channel is detected to have local
data loss, then we don't allow a force close attempt, as this may not be
possible, or cause us to play an invalid state.
This commit removes the breach transaction from the
arguments passed to NewBreachRetribution. We already
keep all prior remote commitments on disk in the
commitment log, and load that transaction from disk
inside the method. In practice, the one loaded from
disk will be the same one that is passed in by the
caller, so there should be no change in behavior
as we've already derived the appropriate state number.
This changes makes integration with the watchtower
client simpler, since we no longer need to acquire
the breaching commitment transaction to be able to
construct the BreachRetribution. This simplifies
not only the logic surrounding transient backsups,
but also on startup (and later, retroactively
backing up historic updates).
This tests make sure we don't reset our expected fee upate after signing
our next commitment. This test would fail without the previous set of
commits.
Instead of special casing the UpdateFee messages, we instead add them to
the update logs like any other HTLC update message. This lets us avoid
having to keep an extra set of variables to keep track of the fee
updates, and instead reuse the commit/ack logic used for other updates.
This fixes a bug where we would reset the pendingFeeUpdate variable
after signing our next commitment, which would make us calculate the new
fee incorrectly if the remote sent a commitment concurrently.
When restoring state logs, we also make sure to re-add any fee updates.
When compacting the update logs we remove any fee updates when they
remove height is passed. We do this since we'll assume fee updates are
added and removed at the same commit height, as they will apply for all
commitments following the fee update.
This commit adds conversion between the lnwire.UpdateFee message and the
new FeeUpdate PaymentDescriptor. We re-purpose the existing Amount field
in the PaymentDescriptor stuct to hold the feerate.
This commit adds a new updateType that can be used for
PaymentDescriptors: FeeUpdate. We repurpose the fields of the existing
PaymentDescriptor struct such that we can easily re-use the commit/ack
logic used for other update types also for fee updates.
In this commit, we add a new method WithCoinSelectLock. This method will
allow us to fix bugs in the project atm that can arise if a channel
funding is attempted (either manually or by autopilot) while a users is
attempting to send an on-chain transaction. If this happens
concurrently, then both contexts will grab the set of UTXOs and attempt
to lock them one by one. However, since they didn't obtain an exclusive
snapshot of the UTXO set of the wallet, they may both attempt to lock
the same input.
We also ensure that calls to SendMany cannot run into this issue by
using the WithCoinSelectLock synchronization when attempting to instruct
the internal wallet to send payments.
In this commit, we extend the WitnessGenerator type to now return an
InputScript. This allows it to be more encompassing, as now callers can
expect a sigScript to be populated if the input being swept requires a
sigScript field.
Along the way, we've also renamed input.BuildWitness to
input.CraftInputScript. We also take a step towards allowing the
sweeper to sweep transactions for n2pwkh outputs. We do so by modifying
the BuiltWitness method to instead return an InputScript. Additionally,
when populating inputs if a sigScript is present, it will now be
populated.
In this commit, we remove the per channel `sigPool` within the
`lnwallet.LightningChannel` struct. With this change, we ensure that as
the number of channels grows, the number of gouroutines idling in the
sigPool stays constant. It's the case that currently on the daemon, most
channels are likely inactive, with only a hand full actually
consistently carrying out channel updates. As a result, this change
should reduce the amount of idle CPU usage, as we have less active
goroutines in select loops.
In order to make this change, the `SigPool` itself has been publicly
exported such that outside callers can make a `SigPool` and pass it into
newly created channels. Since the sig pool now lives outside the
channel, we were also able to do away with the Stop() method on the
channel all together.
Finally, the server is the sub-system that is currently responsible for
managing the `SigPool` within lnd.
