rust-lightning

Add `counterparty_node_id` to `TransactionType` variants

This adds `counterparty_node_id` tracking to all `TransactionType`
variants, enabling downstream users to identify the channel counterparty
associated with each broadcast transaction.

For single-channel variants (`CooperativeClose`, `UnilateralClose`,
`AnchorBump`, `Claim`, `Splice`), the counterparty is stored directly.

For multi-channel variants (`Funding`, `Sweep`), the type now uses
`Vec<(PublicKey, ChannelId)>` to pair each channel with its counterparty.

The `OnchainTxHandler` now stores `counterparty_node_id` and provides a
`set_counterparty_node_id` method for initialization during
deserialization of older data.

Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>

Add `counterparty_node_id` to `TrackedSpendableOutput`

This adds an optional `counterparty_node_id` field to
`TrackedSpendableOutput` and updates the `track_spendable_outputs`
method signatures on both `OutputSweeper` and `OutputSweeperSync` to
accept this new parameter.

The field uses TLV type 3 (odd) for backwards compatibility. When
reading outputs tracked with LDK 0.2 and prior, this field will be
`None`.

Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>

Add `counterparty_node_id` to `Event::SpendableOutputs`

This adds an optional `counterparty_node_id` field to the
`SpendableOutputs` event, providing users with information about which
channel counterparty the spendable outputs belong to.

The field uses TLV type 3 (odd) for backwards compatibility, meaning
older versions will safely ignore it during deserialization. When
reading events serialized by older LDK versions, this field will be
`None`.

Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>

fuzz: assert no stuck payments in chanmon_consistency

After settling all state at 0xff, verify that pending_payments is empty
for all nodes. If payments remain stuck indefinitely, that indicates a
bug in payment resolution.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

fuzz: add MPP payment support to chanmon_consistency

Add multi-path payment (MPP) fuzzing commands that split payments across
multiple channels:

- send_mpp_payment: direct MPP from source to dest using multiple channels
- send_mpp_hop_payment: MPP via intermediate node with multiple channels
on either or both hops

New fuzz commands:
- 0x70: direct MPP 0->1 (uses all 3 A-B channels)
- 0x71: MPP 0->1->2, multi channels on first hop (A-B)
- 0x72: MPP 0->1->2, multi channels on both hops (A-B and B-C)
- 0x73: MPP 0->1->2, multi channels on second hop (B-C)
- 0x74: single-channel MPP 0->1 (all parts over one channel)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

fuzz: expand chanmon_consistency to 6 channels (3 per peer pair)

This expands the channel monitor consistency fuzz test from 2 channels
to 6 channels (3 between A-B and 3 between B-C), enabling future MPP
payment testing.

Changes:
- Extract `connect_peers!` macro from `make_channel!` to avoid duplicate
peer connections
- Create channel arrays `chan_ab_ids[3]` and `chan_bc_ids[3]`
- Store SCIDs in `chan_ab_scids[3]` and `chan_bc_scids[3]`
- Use funding transaction versions 1-6 to avoid txid collisions under
fuzz hashing (which XORs all bytes to a single byte, causing versions
0-5 to collide between A-B and B-C channel pairs)
- Update `test_return!` assertions to expect 3/6/3 channels

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Let Claude run per-crate/feature tests

Previously, we instructed Claude to always run `./ci/ci-tests.sh` which
doesn't seem to work well in practice, as he seems to also employ some
kind of timeout, potentially leading to him getting stuck.

Here we update `CLAUDE.md` accordingly, having him only run `cargo test`

Hold in-flight monitor updates until background event processing

We previously assumed background events would eventually be processed
prior to another `ChannelManager` write, so we would immediately remove
all in-flight monitor updates that completed since the last
`ChannelManager` serialization. This isn't always the case, so we now
keep them all around until we're ready to handle them, i.e., when
`process_background_events` is called.

This was discovered while fuzzing `chanmon_consistency_target` on the
main branch with some changes that allow it to connect blocks. It was
triggered by reloading the `ChannelManager` after a monitor update
completion for an outgoing HTLC, calling
`ChannelManager::best_block_updated`, and reloading the `ChannelManager`
once again. A test is included that provides a minimal reproduction of
this case.

Rustfmt ChannelManager::process_background_events

Make get_latest_mon_update_id a helper on TestChainMonitor

Rename test default channel config

Now that anchor channels are the default,
rename `test_default_anchors_channel_config` to
`test_default_channel_config` and the
previous default to legacy.

Default to anchor channels

Set `negotiate_anchors_zero_fee_htlc_tx` default
to true.

Remove automatic channel acceptance

Removes the `manually_accept_inbound_channels` config
option. In upcoming commit we will default to anchor
channels which requires users checking if they have
enough onchain funds to cover fees in case of a force
close. Hence, we move to always require users to
manually accept inbound channels.

Fix off-by-one for unfunded channel peers

When accepting channels manually, it would
fail if the # of peers without funded channels
was == `MAX_UNFUNDED_CHANNEL_PEERS`, however,
it should fail if the # of peers > `MAX_UNFUNDED_CHANNEL_PEERS`.

Drop `SplicePrototype` feature

Now that `SplicePrototype` and `SpliceProduction` share the same
feature bit, there's not really any reason to have the
`SplicePrototype` feature at all. Instead, we drop it, leaving only
a `Splice` feature.

Switch `SplicePrototype` feature flag to the prod feature bit

When we shipped 0.2 we used the feature bit 155 to signal splicing,
in line with what eclair was using. However, eclair was actually
using that bit to signal splicing on a previous design which is
incompatible with the current spec.

The result of this was that eclair nodes may attempt to splice
using their protocol and we'd fail to deserialize their splice
message (resulting in a reconnect, which luckily would clear their
splice attempt and return the connection to normal).

As we really need to get off of their feature bit and there's not
much reason to keep using a non-final-spec bit, we simply redefine
`SplicePrototype` to bit 63 here.

Support async signing of interactive-tx initial commitment signatures

This commit allows for an async signer to immediately return upon a call
to `EcdsaChannelSigner::sign_counterparty_commitment` for the initial
commitment signatures of an interactively funded transaction, such that
they can call back in via `ChannelManager::signer_unblocked` once the
signatures are ready. This is done for both splices and dual-funded
channels, though note that the latter still require more work to be
integrated. Since `tx_signatures` must be sent only after exchanging
`commitment_signed`, we make sure to hold them back if they're ready to
be sent until our `commitment_signed` is also ready.

fuzz: fix ChaCha20 encrypt_single_block to preserve data

The fuzzing ChaCha20 implementation's encrypt_single_block was not
copying src to dest, causing encrypted data to be lost (dest remained
zeros). This broke payment flows where metadata is encrypted into
payment_secret - the receiver would decrypt zeros and detect the wrong
payment method (LdkPaymentHash instead of UserPaymentHash), causing
payments to fail with "mismatching preimage".

Fix by making encrypt_single_block copy src to dest (identity
encryption), matching the behavior of the process() method.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Simplify in_flight_monitor_updates from Option<HashMap> to HashMap

Since there is no semantic difference between None and Some(empty map)
for in_flight_monitor_updates, simplify the type to HashMap and use
unwrap_or_default() when reading from TLV fields.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Combine claimable HTLCs with purposes in ChannelManagerData

Move the reconstruction of claimable_payments from the main
ChannelManager::read into ChannelManagerData::read. This removes
the separate claimable_htlc_purposes and claimable_htlc_onion_fields
fields from ChannelManagerData, replacing them with the combined
claimable_payments HashMap.

This requires adding a node_signer parameter to ChannelManagerDataReadArgs
to support verification of legacy hop data when reconstructing payment
purposes for very old serialized data (pre-0.0.107).

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Simplify peer_storage_dir from Option<Vec> to Vec in ChannelManagerData

Since there is no semantic difference between None and Some(empty vec)
for peer_storage_dir, simplify the type to Vec and use unwrap_or_default()
when reading from TLV fields.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Use consistent unwrap_or_else pattern for optional TLV fields

Initialize pending_claiming_payments and monitor_update_blocked_actions_per_peer
with None and resolve with unwrap_or_else, matching the pattern used for other
optional hash map fields like pending_intercepted_htlcs_legacy.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Group legacy fields in ChannelManagerData to deduplicate comment

Reorder the struct fields to place all three `_legacy` fields together
at the end, allowing the explanatory comment to appear once instead of
being duplicated three times.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Add a `custom` TLV read/write variant

At various points we've been stuck in our TLV read/write variants
but just want to break out and write some damn code to initialize
a field and some more code to decide what to write for a TLV.

We added the write-side part of this with the `legacy` TLV
read/write variant, but its useful to also be able to specify a
function which is called on the read side.

Here we add a `custom` TLV read/write variant which calls a method
both on read and write to either decide what to write or to map a
read value (if any) to the final field.

Use SignedAmount::unsigned_abs to avoid overflow

In debug mode, using SignedAmount::abs can lead to an integer overflow
when used with SignedAmount::MIN. Use SignedAmount::unsigned_abs to
avoid this.