Update the ChannelLink interface to specifically
return the LinkError struct. This error implements
the ClearTextError interface, so will be picked
up as a routing realted error by the router.
With LinkErrors implemented, the switch now
returns a LinkError for all failures on our
incoming/outgoing link and ForwardingError when
the failure occurs down the line.
This change introduces a LinkError implementation
of the ClearTextError interface. This error is intended
to represent failures which occur on our incoming and
outgoing link when sending, receiving and forwarding
htlcs. Paired with ForwardingError, which is represents
failures that did not occur at our node, this error
covers all non-opaque errors that the switch experiences.
This commit adds a ClearTextError interface
which is implemented by non-opaque errors that
we know the underlying wire failure message for.
This interface is implemented by ForwardingErrors,
because we can fully decrypt the onion blob to
obtain the underlying failure reason. This interface
will also be implemented by errors which originate
at our node in following commits, because we know
the failure reason when we fail the htlc.
The lnwire interface is un-embedded in the
ForwardingError struct in favour of implementing
this interface. This change is made to protect
against accidental passing of a ForwardingError
to the wire, where the embedded FailureMessage
interface will present as wire failure but
will not serialize properly.
Add a constructor for the creation of forwarding errors.
A special constructor is added for the case where we have
an unknown wire failure, and must set a nil failure message.
In this commit, we add a new method to the ErrorEncrypter interface:
`EncryptMalformedError`. This takes a raw error (no encryption or MAC),
and encrypts it as if we were the originator of this error. This will be
used by the switch to convert malformed fail errors to regular fully
encrypted errors.
This commit adds a new field to the ForwardingError struct: ExtraMsg.
The purpose of this field is to allow the htlcswitch to tack on
additional error context to ForwardingError messages returned to the L3
router.
This commit renames the Deobfuscator interface to ErrorDecrypter and
the Obfuscator interface to ErrorEncrypter. With this rename, the
purpose of these two interfaces are a bit clearer.
Additionally, DecryptError (which was formerly Deobfuscate) now
directly returns an ForwardingError type instead of the
lnwire.FailureMessage.
This commit introduces a new type to the package: ForwardingError. It
wraps an existing lnwire.FailureMessage interface, and also includes
the _source_ of the error message. By including the source of the
message, the router can now prune the set of available routes down in
order to reduce the number of subsequent failures based on the source
of the error and the type of the error itself.
Within the network, it's important that when an HTLC forwarding failure
occurs, the recipient is notified in a timely manner in order to ensure
that errors are graceful and not unknown. For that reason with
accordance to BOLT №4 onion failure obfuscation have been added.
