When handling shutdown messages, Channel cannot move to
ChannelState::ShutdownComplete. Remove the code in ChannelManager that
adds a MessageSendEvent::BroadcastChannelUpdate in this case since it is
unreachable.
When a shutdown script is omitted from open_channel or accept_channel,
it must be provided when sending shutdown. Generate the shutdown script
at channel closing time in this case rather at channel opening.
This requires producing a ChannelMonitorUpdate with the shutdown script
since it is no longer known at ChannelMonitor creation.
KeysInterface::get_shutdown_pubkey is used to form P2WPKH shutdown
scripts. However, BOLT 2 allows for a wider variety of scripts. Refactor
KeysInterface to allow any supported script while still maintaining
serialization backwards compatibility with P2WPKH script pubkeys stored
simply as the PublicKey.
Add an optional TLV field to Channel and ChannelMonitor to support the
new format, but continue to serialize the legacy PublicKey format.
BOLT 2 enumerates the script formats that may be used for a shutdown
script. KeysInterface::get_shutdown_pubkey returns a PublicKey used to
form one of the acceptable formats (P2WPKH). Add a ShutdownScript
abstraction to encapsulate all accept formats and be backwards
compatible with P2WPKH scripts serialized as the corresponding
PublicKey.
This clarifies the docs for `PeerManager::timer_tick_occurred` to
note that the call rate is entirely up to the user, and also
suggests a faster ping rate of "once every five to ten seconds"
instead of "every 30 seconds". There isn't a lot of reason to want
to ping less often, and faster ping means we detect disconnects
sooner, which is important.
If we forward an HTLC to our counterparty, but we force-closed the
channel before our counterparty provides us an updated commitment
transaction, we'll end up with a commitment transaction that does
not contain the HTLC which we attempted to forward. In this case,
we need to wait `ANTI_REORG_DELAY` blocks and then fail back the
HTLC as there is no way for us to learn the preimage and the
confirmed commitment transaction paid us the value of the HTLC.
However, check_spend_holder_transaction did not do this - it
instead only looked for dust HTLCs in the confirmed commitment
transaction, paying no attention to what other HTLCs may exist that
are missed.
This will eventually lead to channel force-closure as the channel
on which we received the inbound HTLC to forward will be closed in
time for the initial sender to claim the HTLC on-chain.
This extracts the HTLC-not-in-broadcasted-commitment-transaction
code from check_spend_counterparty_transaction and moves it to a
global macro, DRYing up the two very similar codepaths (fixing
some minor logging inconsistencies) in the process.
This macro will be used for local commitment transaction HTLC
failure as well in the next commit.
This commit has no functional change outside of logging.
This is one of the riskiest parts of our API from the perspective
of accidental force-closes - if users delay persisting the
ChannelManager much at all after a ChannelMonitor we may hit a
force-close after restart.
The fact that we don't log at all when this happens is criminal.
This allows TLV serialization macros to read non-Option-wrapped
types but allow them to be missing, filling them in with the
provided default value as needed.
While we should never reach `ClaimFundsFromHop::DuplicateClaim` in
most cases, if we do, it likely indicates the HTLC was timed out
some time ago and is no longer available to be claimed. Thus, it
does not make sense to imply that we `claimed_any_htlcs`.
It is useful for accounting and informational reasons for users to
be informed when a payment has been successfully forwarded. Thus,
when an HTLC which represents a forwarded leg is claimed, we
generate a new `PaymentForwarded` event.
This requires some additional plumbing to return HTLC values from
`OnchainEvent`s. Further, when we have to go on-chain to claim the
inbound side of the payment, we do not inform the user of the fee
reward, as we cannot calculate it until we see what is confirmed
on-chain.
Substantial code structure rewrites by:
Valentine Wallace <vwallace@protonmail.com>
If we first see a local commitment transaction, and then a reorg
causes the confirmed channel close transaction to instead be a
remote commitment transaction, we would fail a spurious `if else`
check, resulting in us not generating the correct `SpendableOutput`
event for the to_remote output now confirmed on chain.
This resolves the incorrect logic and adds a regression test.
test_onchain_to_onchain_claim was connecting additional blocks in
order to reach HTLC timeout and broadcast an HTLC-Timeout
transaction, resulting in it not testing whether HTLC preimages are
learned instantly in response to HTLC-Success transactions.
This should provide some additional future extensibility, allowing
for new informational events which can be safely ignored to be
ignored by older versions.
The wait_threshold_conf!() macro in check_spend_holder_transaction
was only used once, making it a good candidate for inlining at the
callsite. Further, it incorrectly always logged that we were
failing HTLCs from the "latest" commitment transaction, when it is
sometimes actually failing HTLCs from the previous commitment
transaction.
Previously, we could fail to generate a new commitment transaction
but it simply indicated we had gone to doule-claim an HTLC. Now
that double-claims are returned instead as Ok(None), we should
handle the error case and fail the channel, as the only way to hit
the error case is if key derivation failed or the user refused to
sign the new commitment transaction.
This also resolves an issue where we wouldn't inform our
ChannelMonitor of the new payment preimage in case we failed to
fetch a signature for the new commitment transaction.
When receiving an update_fulfill_htlc message, we immediately
forward the claim backwards along the payment path before waiting
for a full commitment_signed dance. This is great, but can cause
duplicative claims if a node sends an update_fulfill_htlc message,
disconnects, reconnects, and then has to re-send its
update_fulfill_htlc message again.
While there was code to handle this, it treated it as a channel
error on the inbound channel, which is incorrect - this is an
expected, albeit incredibly rare, condition. Instead, we handle
these double-claims correctly, simply ignoring them.
With debug_assertions enabled, we also check that the previous
close of the same HTLC was a fulfill, and that we are not moving
from a HTLC failure to an HTLC claim after its too late.
A test is also added, which hits all three failure cases in
`Channel::get_update_fulfill_htlc`.
Found by the chanmon_consistency fuzzer.
