This moves the common `if during_startup { push background event }
else { apply ChannelMonitorUpdate }` pattern by simply inlining it
in `handle_new_monitor_update`.
One of the largest gaps in our async persistence functionality has
been preimage (claim) updates to closed channels. Here we finally
implement support for this (for updates which are generated during
startup).
Thanks to all the work we've built up over the past many commits,
this is a fairly straightforward patch, removing the
immediate-completion logic from `claim_mpp_part` and adding the
required in-flight tracking logic to
`apply_post_close_monitor_update`.
Like in the during-runtime case in the previous commit, we sadly
can't use the `handle_new_monitor_update` macro wholesale as it
handles the `Channel` resumption as well which we don't do here.
On startup, we walk the preimages and payment HTLC sets on all our
`ChannelMonitor`s, re-claiming all payments which we recently
claimed. This ensures all HTLCs in any claimed payments are claimed
across all channels.
In doing so, we expect to see the same payment multiple times,
after all it may have been received as multiple HTLCs across
multiple channels. In such cases, there's no reason to redundantly
claim the same set of HTLCs again and again. In the current code,
doing so may lead to redundant `PaymentClaimed` events, and in a
coming commit will instead cause an assertion failure.
One of the largest gaps in our async persistence functionality has
been preimage (claim) updates to closed channels. Here we finally
implement support for this (for updates at runtime).
Thanks to all the work we've built up over the past many commits,
this is a well-contained patch within `claim_mpp_part`, pushing
the generated `ChannelMonitorUpdate`s through the same pipeline we
use for open channels.
Sadly we can't use the `handle_new_monitor_update` macro wholesale
as it handles the `Channel` resumption as well which we don't do
here.
In d1c340a0e1 we added support in
`handle_new_monitor_update!` for handling updates without dropping
locks.
In the coming commits we'll start handling `ChannelMonitorUpdate`s
"like normal" for updates against closed channels. Here we set up
the first step by adding a new `POST_CHANNEL_CLOSE` variant on
`handle_new_monitor_update!` which attempts to handle the
`ChannelMonitorUpdate` and handles completion actions if it
finishes immediately, just like the pre-close variant.
In c99d3d785d we added a new
`apply_post_close_monitor_update` method which takes a
`ChannelMonitorUpdate` (possibly) for a channel which has been
closed, sets the `update_id` to the right value to keep our updates
well-ordered, and then applies it.
Setting the `update_id` at application time here is fine - updates
don't really have an order after the channel has been closed, they
can be applied in any order - and was done for practical reasons
as calculating the right `update_id` at generation time takes a
bit more work on startup, and was impossible without new
assumptions during claim.
In the previous commit we added exactly the new assumption we need
at claiming (as it's required for the next few commits anyway), so
now the only thing stopping us is the extra complexity.
In the coming commits, we'll move to tracking post-close
`ChannelMonitorUpdate`s as in-flight like any other updates, which
requires having an `update_id` at generation-time so that we know
what updates are still in-flight.
Thus, we go ahead and eat the complexity here, creating
`update_id`s when the `ChannelMonitorUpdate`s are generated for
closed-channel updates, like we do for channels which are still
live.
We also ensure that we always insert `ChannelMonitorUpdate`s in the
pending updates set when we push the background event, avoiding a
race where we push an update as a background event, then while its
processing another update finishes and the post-update actions get
run.
Now that we track the latest `ChannelMonitorUpdate::update_id` for
each closed channel in
`PeerState::closed_channel_monitor_update_ids`, we should always
have a `PeerState` entry for the channel counterparty any time we
go to claim an HTLC on a channel, even if its closed.
Here we make this a hard assertion as we'll need to access that
`PeerState` in the coming commits to track in-flight updates
against closed channels.
UnknownPaymentContext is used when payment::ReceiveTlvs doesn't contain
a PaymentContext. This is only needed for a legacy BlindedPaymentPath.
Since these paths a short-lived, UnknownPaymentContext is no longer
needed. Remove it and require that payment::ReceiveTlvs always contains
a PaymentContext.
Any such path would fail authentication since the payment::ReceiveTlvs
would be missing an HMAC and Nonce, so this is a good time to remove
UnknownPaymentContext.
When receiving a payment over a BlindedPaymentPath, a PaymentContext is
included but was not authenticated. The previous commit adds an HMAC of
the payment::ReceiveTlvs (which contains the PaymentContext) and the
nonce used to create the HMAC. This commit verifies the authenticity
when parsing the InboundOnionPayload. This prevents a malicious actor
from for forging it.
In order to authenticate a PaymentContext, an HMAC and Nonce must be
included along with it in payment::ReceiveTlvs. Compute the HMAC when
constructing a BlindedPaymentPath and include it in the recipient's
BlindedPaymentTlvs. Authentication will be added in an upcoming commit.
Now that NodeSigner::get_inbound_payment_key returns an ExpandedKey
instead of KeyMaterial, the latter is no longer needed. Remove
KeyMaterial and replace its uses with [u8; 32].
NodeSinger::get_inbound_payment_key_material returns KeyMaterial, which
is used for constructing an ExpandedKey. Change the trait to return an
ExpandedKey directly instead. This allows for direct access to the
ExpandedKey when a NodeSigner referenced is available. Otherwise, it
would either need to be reconstructed or passed in separately.
When receiving a PaymentContext from a blinded payment, the context must
be authenticated. Otherwise, the context can be forged and would appear
within a PaymentPurpose. Add functions for constructing and verifying an
HMAC for the ReceiveTlvs, which contains the PaymentContext.
This commit adds counterparty node IDs to `PaymentForwarded`
to address the potential ambiguity of using `ChannelIds` alone,
especially in cases like v1 0conf opens where `ChannelIds`
may not be unique. Including the counterparty node IDs
provides better clarity and makes the information more useful.
A claim transaction with locktime T can only be mined at block heights
of T+1 or above, so it should only be broadcast at height T or above.
Due to an off-by-one bug, we were broadcasting some claim transactions
too early at T-1.
AFAICT, nothing bad resulted from this bug -- later rebroadcasts of the
transaction would eventually succeed once the correct height was
reached.
Following up on the previous commit, where we added debug_asserts
within `build_closing_transaction` to ensure neither
`value_to_holder` nor `value_to_counterparty` underflow, we now also
force-close the channel in the (presumably impossible) event that it
did happen.
When batch claiming was first added, it was only done so for claims
which were not pinnable, i.e. those which can only be claimed by us.
This was the conservative choice - pinning of outputs claimed by a batch
would leave the entire batch unable to confirm on-chain. However, if
pinning is considered an attack that can be executed with a high
probability of success, then there is no reason not to batch claims of
pinnable outputs together, separate from unpinnable outputs.
Whether specific outputs are pinnable can change over time - those that
are not pinnable will eventually become pinnable at the height at which
our counterparty can spend them. Outputs are treated as pinnable if
they're within `COUNTERPARTY_CLAIMABLE_WITHIN_BLOCKS_PINNABLE` of that
height.
Aside from outputs being pinnable or not, locktimes are also a factor
for batching claims. HTLC-timeout claims have locktimes fixed by the
counterparty's signature and thus can only be aggregated with other
HTLCs of the same CLTV, which we have to check for.
The complexity required here is worth it - aggregation can save users a
significant amount of fees in the case of a force-closure, and directly
impacts the number of UTXOs needed as a reserve for anchors.
Co-authored-by: Matt Corallo <git@bluematt.me>
This allows us to make the PaymentSendFailure error type private, as well as
reduce the visibility of the vestigial send_payment_with_route method that was
already made test and fuzz-only in a previous commit.
Removes the final usage of PaymentSendFailure from public API.
This (confusing) error matched with prior versions of LDK where users had to
handle payment retries themselves. Since auto-retry was introduced, the only
non-deprecated use remaining was for probe send errors. Probes only have
one path, though, so refactor ProbeSendFailure to omit usage of
PaymentSendFailure.
We don't make this error private yet because it's still used by some fuzzing
code as well as internally to outbound_payments, but it isn't returned by any
public functions anymore.
This method has been deprecated for several versions in favor of
ChannelManager::send_payment, and we want to remove it from the public API
entirely prior to the 0.1 release. However, >150 tests use it so put off
removing the method entirely.
This moves panics to a higher level, allows failures to be handled
gracefully in some cases, and supports more explicit testing without
using `#[should_panic]`.
There are multiple factors affecting the locktime of a package:
- HTLC transactions rely on a fixed timelock due to the counterparty's
signature.
- HTLC timeout claims on the counterparty's commitment transaction
require satisfying a CLTV timelock.
- The locktime can be set to the latest height to avoid fee sniping.
These factors were combined in a single method, making the separate
factors less clear.
In `build_closing_transaction`, we check that `value_to_holder` and
`value_to_counterparty`, which are signed, are not lower than the
dust limit. However, in doing this check, we convert them to signed
integers, which could result in an underflow and a failed detection.
This scenario should not be reachable, but here we add debug_asserts
to positive ensure that scenario isn't hit.
When a `ChannelMonitor` sees a payment preimage on chain for an
outbound HTLC, it creates a `MonitorEvent` containing the preimage
to pass to the inbound edge. The inclusion of the transaction
containing the payment preimage (plus six confirmations) also
results in the corresponding `Balance` being removed from the live
balance set, allowing the `ChannelMonitor` to be pruned (after a
further 4032 blocks).
While `MonitorEvent`s should always be processed in a timely
manner, if a node is suffering from a bug where they are not, its
possible for 4038 blocks to pass with the preimage-containing
`MonitorEvent` still pending. If that happens, its possible the
`ChannelMonitor` is archived even though the preimage in it is
needed in another channel (or `ChannelMonitor`), causing funds
loss.
Luckily the fix is simple - check for pending events before
allowing a `ChannelMonitor` to be archived.
Fixes#2153
At various points we've had issues where `Event` processing for a
user possibly is taking a long time, causing other things to stall.
However, due to lack of logging during `Event` processing itself
this can be rather difficult to debug. In
85eb8145fb we attempted to add
logging for this, but in doing so ended up with more verbose
logging than we were comfortable with.
Instead, here, we log only when we actually process an `Event`,
directly in the callsite passing the `Event` to the user.
Fixes#3331
