Introduces a new chancloser package which exposes a ChanCloser
struct that handles the cooperative channel closure negotiation
and is meant to replace chancloser.go in the lnd package. Updates
all references to chancloser.go to instead use chancloser package.
This commit enables the user to specify he is not interested in
automatically close channels with pending payments that their
corresponding htlcs have timed-out.
By requiring a configurable grace period uptime of our node
before closing such channels, we give a chance to the other node to
properly cancel the htlc and avoid unnecessary on-chain transaction.
In mobile it is very important for the user experience as otherwise
channels will be force closed more frequently.
We abstract away how keys are generated for the different channel types
types (currently tweak(less)).
Intention is that more of the logic that is unique for each commitment
type lives in commitment.go, making the channel state machine oblivious
to the keys and outputs being created on the commitment tx for a given
channel state.
This commit is adapted from @Bluetegu's original
pull request #1462.
This commit reads an optional address to pay funds out to
from a user iniitiated close channel address. If the channel
already has a shutdown script set, the request will fail if
an address is provided. Otherwise, the cooperative close will
pay out to the address provided.
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).
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.
This commit makes the outgoing link pipeline the settle to the
switch as soon as it receives it. Previously, it would wait for a
revocation before sending it, which caused increased latency on
payments as well as possibly never settling on the incoming link.
A duplicate settle is still sent to the switch, but it is handled
gracefully. A new AckEventTicker was added to the switch which
acknowledges any pending settle / fail entries in an outgoing
link's fwd pkgs in batch. This was needed in order to reduce the
number of db txn's which would have been incurred by acking whenever
we receive a duplicate settle without batching.
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 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.
Previously, nursery generated and published its own sweep txes. It
stored the sweep tx in nursery_store to prevent a new tx with a new
sweep address from being generated on restart.
In this commit, sweep generation and publication is removed from nursery
and delegated to the sweeper. Also the confirmation notification is
received from the sweeper.
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.
In this commit, we fix a small bug with regards to the persistent peer
connection pruning logic. Before this commit, it'd be the case that we'd
prune a persistent connection to a peer if all links happen to be
inactive. This isn't ideal, as the channels are still open, so we should
always be atttempting to connect to them. We fix this by looking at the
set of channels on-disk instead and prune the persistent connection if
there aren't any.
In this commit, we move the block height dependency from the links in
the switch to the switch itself. This is possible due to a recent change
on the links no longer depending on the block height to update their
commitment fees.
We'll now only have the switch be alerted of new blocks coming in and
links will retrieve the height from it atomically.
In this commit, we address an un accounted for case during the breach
remedy process. If the remote node actually went directly to the second
layer during a channel breach attempt, then we wouldn’t properly be
able to sweep with out justice transaction, as some HTLC inputs may
actually be spent at that point.
In order to address this case, we’ll now catch the transaction
rejection, then check to see which input was spent, promote that to a
second level spend, and repeat as necessary. At the end of this loop,
any inputs which have been spent to the second level will have had the
prevouts and witnesses updated.
In order to perform this transition, we now also store the second level
witness script in the database. This allow us to modify the sign desc
with the proper input value, as well as witness script.
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.
With the new negotiation policy, we instead just need to ensure that
our fee inches closer to the other party’s with each iteration, and
that it’s within the proper bounds.
This commit adds the fee negotiation procedure performed
on channel shutdown. The current algorithm picks an ideal
a fee based on the FeeEstimator and commit weigth, then
accepts the remote's fee if it is at most 50%-200% away
from the ideal. The fee negotiation procedure is similar
both as sender and receiver of the initial shutdown
message, and this commit also make both sides use the
same code path for handling these messages.
