We add this constructor for an AuxHtlcDescriptor that allows setting
some of the internal fields. This is useful for testing purposes for
code external to this package that may need to extensively test the
AuxHtlcView.
When instantiating the lightning channel we now pass in the created HTLC
validator. This validator simply performs a bandwidth check and errors
out if that is insufficient.
Previously we'd perform aux bandwidth checks during path finding. This
could lead to issues where multiple HTLCs where querying the same
bandwidth but were not accounting for each other before being added to
the commitment log. We now add a new validator function that will serve
as the last point of checks before adding the HTLC to the commitment.
During path finding HTLCs could query channel bandwidth asynchronously.
At this new call site all HTLCs that are about to be added to the
channel have been organised in sequence, so it's safe to query bandwdith
again at this point as we're getting the actual up-to-date values.
We remove the aux bandwidth check from the helper canSendHtlc, which was
called from CheckHTLCTransit and CheckHTLCForward (both are methods of
the htlcswitch).
For forwards we now fail at the link level, following the introduction
of the AuxHtlcValidator.
For payments, we now may fail either at the pathfinding level, or at the
link level. The htlcswitch may no longer fail for aux bandwidth checks.
Finally, when fetching the latest htlc view (for bandwidth checks during
pathfinding) we'd silently set the nextHeight of the view to the default
zero value. We now make sure to set it to the correct nextHeight value.
We now execute the aux chan closer finalization within the chain
watcher. This is better as we don't need to rely on the remote party
being online and sending us a message. Instead we do the finalization
once the on-chain transaction has been confirmed.
The aux close types will soon be used by a different package that would
otherwise cause an import cycle if used directly from
lnwallet/chancloser. We now create a new sub-package lnwallet/types that
will be improrted from all users of these types.
Add the new RPC method that looks up the base scid for a given alias.
Given the previous stepping stones this commit is fairly simple, we just
call into the alias manager and return the lookup result.
We add an extra option to the AddLocalAlias method which only controls
whether we store a reverse lookup from the alias back to the base scid
it corresponds to. The previous flag "gossip" is still maintained, and
in a way supercedes the new flag (it will also store the base scid
lookup even if the base lookup flag isn't set). The only call that sets
this option is the XAddLocalChanAlias RPC endpoint, where we want to
make sure that a reverse lookup is stored in the alias manager in order
to later expose it via the new RPC method.
In order to help external components to query the custom records of a
channel we need to expose the remote peer pub key. We could look-up
custom records based on the funding outpoint, but that relation is
established when receiving the ChannelReady message. The external
components may query the AuxChanState before that message is received,
so let's make sure the peer pub key is also available.
This is the final step, we actually call the interface and either
provide or retrieve the custom features over the message. We also notify
the aux components when channel reestablish is received.
We now plug-in the aux channel negotiator to the server impl config. We
also provide it to the peer config as that's where it's needed in order
to inject custom records in the appropriate peer messages.
We introduce this new interface with the purpose of injecting and
handling custom records on the init message, and also notifying
external components when receiving the ChannelReady or
ChannelReestablish message.
To make sure we don't cause force-closures because of commit sig
mismatches, we add a test case to verify that the retransmitted HTLC
matches the original HTLC.
We update the lightning channel state machine in some key areas. If the
noop TLV is set in the update_add_htlc custom records then we change the
entry type to noop. When settling the HTLC if the type is noop we credit
the satoshi amount back to the sender.
We add a new update type to the payment descriptor to describe this new
type of htlc. This type of HTLC will only end up being set if explicitly
signalled by external software.
In order to get more precise bandwidth reports, we also need to provide
this method with the latest htlc view. Since aux data is committed to in
the channel commitment, some uncommited HTLCs may not be accounted for,
so we need to manually provide them via the HTLC view.
When notifying the invoice registry for an exit hop htlc we also want to
include its custom records. The channelLink, the other caller of this
method, already populates this field. So we make sure the contest
resolver does so too.
This commit was added to the 0-19-staging branch recently and therefore
didn't make it into a previous part yet. So it's unrelated to the
changes in this part but is required for the whole custom channel saga.
George Tsagkarelis