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Include excess counterparty commitment transaction fees in dust exposure - #3045

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TheBlueMatt merged 6 commits into
lightningdevkit:mainfrom
TheBlueMatt:2024-03-fees-are-dust
May 7, 2024
Merged

Include excess counterparty commitment transaction fees in dust exposure#3045
TheBlueMatt merged 6 commits into
lightningdevkit:mainfrom
TheBlueMatt:2024-03-fees-are-dust

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@TheBlueMatt

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Transaction fees on counterparty commitment transactions are
ultimately not our money and thus are really "dust" from our PoV -
they're funds that may be ours during off-chain updates but are not
ours once we go on-chain.

Thus, here, we count any such fees in excess of our own fee
estimates towards dust exposure. We don't bother to make an
inbound/outbound channel distinction here as in most cases users
will use MaxDustExposure::FeeRateMultiplier which will scale
with the fee we set on outbound channels anyway.

Note that this also enables the dust exposure checks on anchor
channels during feerate updates. We'd previously elided these as
increases in the channel feerates do not change the HTLC dust
exposure, but now do for the fee dust exposure.

Also updates our default limit, fixing #2922

In most cases we already call both in a pair, and in fact always
consolidate some of the returned values across both accessors, so
there's not much reason to have them be separate methods.
Here we merge them.
The previous commit left indentation in `get_pending_htlc_stats`
deliberately wrong, to ease reviewability. This commit fixes the
indentation.
As LDK changes, `UserConfig::default()` may imply marginally
different behavior, whereas `test_default_channel_config` is
intended to tweak defaults to provide a stable behavior for test
contexts.
This commit changes a few uses of `UserConfig::default()` to
`test_default_channel_config` in cases that will fail over the
coming commits due to dust changes.
Transaction fees on counterparty commitment transactions are
ultimately not our money and thus are really "dust" from our PoV -
they're funds that may be ours during off-chain updates but are not
ours once we go on-chain.
Thus, here, we count any such fees in excess of our own fee
estimates towards dust exposure. We don't bother to make an
inbound/outbound channel distinction here as in most cases users
will use `MaxDustExposure::FeeRateMultiplier` which will scale
with the fee we set on outbound channels anyway.
Note that this also enables the dust exposure checks on anchor
channels during feerate updates. We'd previously elided these as
increases in the channel feerates do not change the HTLC dust
exposure, but now do for the fee dust exposure.
Now that we're including excess counterparty commitment transaction
fees in our dust calculation, we need to update the docs
accordingly. We do so here, describing some of the considerations
and risks that come with the new changes.
We also take this opportunity to double the default value, as users
have regularly complained that non-anchor channels fail to send
HTLCs with the default settings with some feerates.
Fixeslightningdevkit#2922
@TheBlueMattTheBlueMatt added this to the 0.0.123 milestone May 7, 2024
@TheBlueMattTheBlueMatt linked an issue May 7, 2024 that may be closed by this pull request
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Codecov Report

Attention: Patch coverage is 94.03974% with 18 lines in your changes are missing coverage. Please review.

Project coverage is 90.65%. Comparing base (8701b1b) to head (5091c1f).
Report is 37 commits behind head on main.

FilesPatch %Lines
lightning/src/ln/channel.rs93.49%9 Missing and 2 partials ⚠️
lightning/src/ln/functional_tests.rs94.53%6 Missing and 1 partial ⚠️

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Additional details and impacted files
@@ Coverage Diff @@## main #3045 +/- ##
==========================================
+ Coverage 89.16% 90.65% +1.48% 
==========================================
Files 118 118 Lines 97726 102485 +4759 Branches 97726 102485 +4759 ==========================================
+ Hits 87142 92904 +5762 + Misses 8345 7135 -1210 - Partials 2239 2446 +207 

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@jkczyz

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Fuzz tests failing 😢

@TheBlueMatt

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Grr, its just the stupid no_existing_breakage test. I'll work on it but IMO we can merge it with that broken, cut an RC, and then fix for release.

@dunxendunxen left a comment

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LGTM. Thanks for the docs :)

@TheBlueMatt
TheBlueMatt merged commit d1ac071 into lightningdevkit:mainMay 7, 2024
TheBlueMatt added a commit to TheBlueMatt/rust-lightning that referenced this pull request May 7, 2024
…-are-dust
Include excess counterparty commitment transaction fees in dust exposure
PXplod pushed a commit to bitlightlabs/rust-lightning that referenced this pull request Sep 30, 2024
v0.0.123 - May 08, 2024 - "BOLT12 Dust Sweeping"
API Updates
===========
* To reduce risk of force-closures and improve HTLC reliability the default
dust exposure limit has been increased to
`MaxDustHTLCExposure::FeeRateMultiplier(10_000)`. Users with existing
channels might want to consider using
`ChannelManager::update_channel_config` to apply the new default (lightningdevkit#3045).
* `ChainMonitor::archive_fully_resolved_channel_monitors` is now provided to
remove from memory `ChannelMonitor`s that have been fully resolved on-chain
and are now not needed. It uses the new `Persist::archive_persisted_channel`
to inform the storage layer that such a monitor should be archived (lightningdevkit#2964).
* An `OutputSweeper` is now provided which will automatically sweep
`SpendableOutputDescriptor`s, retrying until the sweep confirms (lightningdevkit#2825).
* After initiating an outbound channel, a peer disconnection no longer results
in immediate channel closure. Rather, if the peer is reconnected before the
channel times out LDK will automatically retry opening it (lightningdevkit#2725).
* `PaymentPurpose` now has separate variants for BOLT12 payments, which
include fields from the `invoice_request` as well as the `OfferId` (lightningdevkit#2970).
* `ChannelDetails` now includes a list of in-flight HTLCs (lightningdevkit#2442).
* `Event::PaymentForwarded` now includes `skimmed_fee_msat` (lightningdevkit#2858).
* The `hashbrown` dependency has been upgraded and the use of `ahash` as the
no-std hash table hash function has been removed. As a consequence, LDK's
`Hash{Map,Set}`s no longer feature several constructors when LDK is built
with no-std; see the `util::hash_tables` module instead. On platforms that
`getrandom` supports, setting the `possiblyrandom/getrandom` feature flag
will ensure hash tables are resistant to HashDoS attacks, though the
`possiblyrandom` crate should detect most common platforms (lightningdevkit#2810, lightningdevkit#2891).
* `ChannelMonitor`-originated requests to the `ChannelSigner` can now fail and
be retried using `ChannelMonitor::signer_unblocked` (lightningdevkit#2816).
* `SpendableOutputDescriptor::to_psbt_input` now includes the `witness_script`
where available as well as new proprietary data which can be used to
re-derive some spending keys from the base key (lightningdevkit#2761, lightningdevkit#3004).
* `OutPoint::to_channel_id` has been removed in favor of
`ChannelId::v1_from_funding_outpoint` in preparation for v2 channels with a
different `ChannelId` derivation scheme (lightningdevkit#2797).
* `PeerManager::get_peer_node_ids` has been replaced with `list_peers` and
`peer_by_node_id`, which provide more details (lightningdevkit#2905).
* `Bolt11Invoice::get_payee_pub_key` is now provided (lightningdevkit#2909).
* `Default[Message]Router` now take an `entropy_source` argument (lightningdevkit#2847).
* `ClosureReason::HTLCsTimedOut` has been separated out from
`ClosureReason::HolderForceClosed` as it is the most common case (lightningdevkit#2887).
* `ClosureReason::CooperativeClosure` is now split into
`{Counterparty,Locally}Initiated` variants (lightningdevkit#2863).
* `Event::ChannelPending::channel_type` is now provided (lightningdevkit#2872).
* `PaymentForwarded::{prev,next}_user_channel_id` are now provided (lightningdevkit#2924).
* Channel init messages have been refactored towards V2 channels (lightningdevkit#2871).
* `BumpTransactionEvent` now contains the channel and counterparty (lightningdevkit#2873).
* `util::scid_utils` is now public, with some trivial utilities to examine
short channel ids (lightningdevkit#2694).
* `DirectedChannelInfo::{source,target}` are now public (lightningdevkit#2870).
* Bounds in `lightning-background-processor` were simplified by using
`AChannelManager` (lightningdevkit#2963).
* The `Persist` impl for `KVStore` no longer requires `Sized`, allowing for
the use of `dyn KVStore` as `Persist` (lightningdevkit#2883, lightningdevkit#2976).
* `From<PaymentPreimage>` is now implemented for `PaymentHash` (lightningdevkit#2918).
* `NodeId::from_slice` is now provided (lightningdevkit#2942).
* `ChannelManager` deserialization may now fail with `DangerousValue` when
LDK's persistence API was violated (lightningdevkit#2974).
Bug Fixes
=========
* Excess fees on counterparty commitment transactions are now included in the
dust exposure calculation. This lines behavior up with some cases where
transaction fees can be burnt, making them effectively dust exposure (lightningdevkit#3045).
* `Future`s used as an `std::...::Future` could grow in size unbounded if it
was never woken. For those not using async persistence and using the async
`lightning-background-processor`, this could cause a memory leak in the
`ChainMonitor` (lightningdevkit#2894).
* Inbound channel requests that fail in
`ChannelManager::accept_inbound_channel` would previously have stalled from
the peer's perspective as no `error` message was sent (lightningdevkit#2953).
* Blinded path construction has been tuned to select paths more likely to
succeed, improving BOLT12 payment reliability (lightningdevkit#2911, lightningdevkit#2912).
* After a reorg, `lightning-transaction-sync` could have failed to follow a
transaction that LDK needed information about (lightningdevkit#2946).
* `RecipientOnionFields`' `custom_tlvs` are now propagated to recipients when
paying with blinded paths (lightningdevkit#2975).
* `Event::ChannelClosed` is now properly generated and peers are properly
notified for all channels that as a part of a batch channel open fail to be
funded (lightningdevkit#3029).
* In cases where user event processing is substantially delayed such that we
complete multiple round-trips with our peers before a `PaymentSent` event is
handled and then restart without persisting the `ChannelManager` after having
persisted a `ChannelMonitor[Update]`, on startup we may have `Err`d trying to
deserialize the `ChannelManager` (lightningdevkit#3021).
* If a peer has relatively high latency, `PeerManager` may have failed to
establish a connection (lightningdevkit#2993).
* `ChannelUpdate` messages broadcasted for our own channel closures are now
slightly more robust (lightningdevkit#2731).
* Deserializing malformed BOLT11 invoices may have resulted in an integer
overflow panic in debug builds (lightningdevkit#3032).
* In exceedingly rare cases (no cases of this are known), LDK may have created
an invalid serialization for a `ChannelManager` (lightningdevkit#2998).
* Message processing latency handling BOLT12 payments has been reduced (lightningdevkit#2881).
* Latency in processing `Event::SpendableOutputs` may be reduced (lightningdevkit#3033).
Node Compatibility
==================
* LDK's blinded paths were inconsistent with other implementations in several
ways, which have been addressed (lightningdevkit#2856, lightningdevkit#2936, lightningdevkit#2945).
* LDK's messaging blinded paths now support the latest features which some
nodes may begin relying on soon (lightningdevkit#2961).
* LDK's BOLT12 structs have been updated to support some last-minute changes to
the spec (lightningdevkit#3017, lightningdevkit#3018).
* CLN v24.02 requires the `gossip_queries` feature for all peers, however LDK
by default does not set it for those not using a `P2PGossipSync` (e.g. those
using RGS). This change was reverted in CLN v24.02.2 however for now LDK
always sets the `gossip_queries` feature. This change is expected to be
reverted in a future LDK release (lightningdevkit#2959).
Security
========
0.0.123 fixes a denial-of-service vulnerability which we believe to be reachable
from untrusted input when parsing invalid BOLT11 invoices containing non-ASCII
characters.
* BOLT11 invoices with non-ASCII characters in the human-readable-part may
cause an out-of-bounds read attempt leading to a panic (lightningdevkit#3054). Note that all
BOLT11 invoices containing non-ASCII characters are invalid.
In total, this release features 150 files changed, 19307 insertions, 6306
deletions in 360 commits since 0.0.121 from 17 authors, in alphabetical order:
* Arik Sosman
* Duncan Dean
* Elias Rohrer
* Evan Feenstra
* Jeffrey Czyz
* Keyue Bao
* Matt Corallo
* Orbital
* Sergi Delgado Segura
* Valentine Wallace
* Willem Van Lint
* Wilmer Paulino
* benthecarman
* jbesraa
* olegkubrakov
* optout
* shaavan
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Rethink default dust limit

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@TheBlueMatt@codecov-commenter@jkczyz@dunxen