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Merge pull request #2478 from waterson/settle-htlcs
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Provide the HTLCs that settled a payment.
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@TheBlueMatt
TheBlueMatt authored Aug 21, 2023
2 parents cb923c6 + 2e562a2 commit 4bd4f02
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Showing 3 changed files with 136 additions and 14 deletions.
47 changes: 46 additions & 1 deletion lightning/src/events/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -79,6 +79,37 @@ impl_writeable_tlv_based_enum!(PaymentPurpose,
(2, SpontaneousPayment)
);

/// Information about an HTLC that is part of a payment that can be claimed.
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct ClaimedHTLC {
/// The `channel_id` of the channel over which the HTLC was received.
pub channel_id: [u8; 32],
/// The `user_channel_id` of the channel over which the HTLC was received. This is the value
/// passed in to [`ChannelManager::create_channel`] for outbound channels, or to
/// [`ChannelManager::accept_inbound_channel`] for inbound channels if
/// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
/// `user_channel_id` will be randomized for an inbound channel.
///
/// This field will be zero for a payment that was serialized prior to LDK version 0.0.117. (This
/// should only happen in the case that a payment was claimable prior to LDK version 0.0.117, but
/// was not actually claimed until after upgrading.)
///
/// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
/// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
/// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
pub user_channel_id: u128,
/// The block height at which this HTLC expires.
pub cltv_expiry: u32,
/// The amount (in msats) of this part of an MPP.
pub value_msat: u64,
}
impl_writeable_tlv_based!(ClaimedHTLC, {
(0, channel_id, required),
(2, user_channel_id, required),
(4, cltv_expiry, required),
(6, value_msat, required),
});

/// When the payment path failure took place and extra details about it. [`PathFailure::OnPath`] may
/// contain a [`NetworkUpdate`] that needs to be applied to the [`NetworkGraph`].
///
Expand Down Expand Up @@ -470,6 +501,12 @@ pub enum Event {
/// The purpose of the claimed payment, i.e. whether the payment was for an invoice or a
/// spontaneous payment.
purpose: PaymentPurpose,
/// The HTLCs that comprise the claimed payment. This will be empty for events serialized prior
/// to LDK version 0.0.117.
htlcs: Vec<ClaimedHTLC>,
/// The sender-intended sum total of all the MPP parts. This will be `None` for events
/// serialized prior to LDK version 0.0.117.
sender_intended_total_msat: Option<u64>,
},
/// Indicates an outbound payment we made succeeded (i.e. it made it all the way to its target
/// and we got back the payment preimage for it).
Expand Down Expand Up @@ -1040,13 +1077,15 @@ impl Writeable for Event {
// We never write the OpenChannelRequest events as, upon disconnection, peers
// drop any channels which have not yet exchanged funding_signed.
},
&Event::PaymentClaimed { ref payment_hash, ref amount_msat, ref purpose, ref receiver_node_id } => {
&Event::PaymentClaimed { ref payment_hash, ref amount_msat, ref purpose, ref receiver_node_id, ref htlcs, ref sender_intended_total_msat } => {
19u8.write(writer)?;
write_tlv_fields!(writer, {
(0, payment_hash, required),
(1, receiver_node_id, option),
(2, purpose, required),
(4, amount_msat, required),
(5, *htlcs, optional_vec),
(7, sender_intended_total_msat, option),
});
},
&Event::ProbeSuccessful { ref payment_id, ref payment_hash, ref path } => {
Expand Down Expand Up @@ -1371,17 +1410,23 @@ impl MaybeReadable for Event {
let mut purpose = UpgradableRequired(None);
let mut amount_msat = 0;
let mut receiver_node_id = None;
let mut htlcs: Option<Vec<ClaimedHTLC>> = Some(vec![]);
let mut sender_intended_total_msat: Option<u64> = None;
read_tlv_fields!(reader, {
(0, payment_hash, required),
(1, receiver_node_id, option),
(2, purpose, upgradable_required),
(4, amount_msat, required),
(5, htlcs, optional_vec),
(7, sender_intended_total_msat, option),
});
Ok(Some(Event::PaymentClaimed {
receiver_node_id,
payment_hash,
purpose: _init_tlv_based_struct_field!(purpose, upgradable_required),
amount_msat,
htlcs: htlcs.unwrap_or(vec![]),
sender_intended_total_msat,
}))
};
f()
Expand Down
53 changes: 46 additions & 7 deletions lightning/src/ln/channelmanager.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -181,6 +181,7 @@ pub(super) enum HTLCForwardInfo {
pub(crate) struct HTLCPreviousHopData {
// Note that this may be an outbound SCID alias for the associated channel.
short_channel_id: u64,
user_channel_id: Option<u128>,
htlc_id: u64,
incoming_packet_shared_secret: [u8; 32],
phantom_shared_secret: Option<[u8; 32]>,
Expand Down Expand Up @@ -221,6 +222,17 @@ struct ClaimableHTLC {
counterparty_skimmed_fee_msat: Option<u64>,
}

impl From<&ClaimableHTLC> for events::ClaimedHTLC {
fn from(val: &ClaimableHTLC) -> Self {
events::ClaimedHTLC {
channel_id: val.prev_hop.outpoint.to_channel_id(),
user_channel_id: val.prev_hop.user_channel_id.unwrap_or(0),
cltv_expiry: val.cltv_expiry,
value_msat: val.value,
}
}
}

/// A payment identifier used to uniquely identify a payment to LDK.
///
/// This is not exported to bindings users as we just use [u8; 32] directly
Expand Down Expand Up @@ -496,11 +508,15 @@ struct ClaimingPayment {
amount_msat: u64,
payment_purpose: events::PaymentPurpose,
receiver_node_id: PublicKey,
htlcs: Vec<events::ClaimedHTLC>,
sender_intended_value: Option<u64>,
}
impl_writeable_tlv_based!(ClaimingPayment, {
(0, amount_msat, required),
(2, payment_purpose, required),
(4, receiver_node_id, required),
(5, htlcs, optional_vec),
(7, sender_intended_value, option),
});

struct ClaimablePayment {
Expand Down Expand Up @@ -3785,6 +3801,7 @@ where
if let PendingHTLCRouting::Forward { short_channel_id, .. } = payment.forward_info.routing {
let htlc_source = HTLCSource::PreviousHopData(HTLCPreviousHopData {
short_channel_id: payment.prev_short_channel_id,
user_channel_id: Some(payment.prev_user_channel_id),
outpoint: payment.prev_funding_outpoint,
htlc_id: payment.prev_htlc_id,
incoming_packet_shared_secret: payment.forward_info.incoming_shared_secret,
Expand Down Expand Up @@ -3832,6 +3849,7 @@ where

let htlc_source = HTLCSource::PreviousHopData(HTLCPreviousHopData {
short_channel_id: prev_short_channel_id,
user_channel_id: Some(prev_user_channel_id),
outpoint: prev_funding_outpoint,
htlc_id: prev_htlc_id,
incoming_packet_shared_secret: incoming_shared_secret,
Expand Down Expand Up @@ -3936,7 +3954,7 @@ where
for forward_info in pending_forwards.drain(..) {
match forward_info {
HTLCForwardInfo::AddHTLC(PendingAddHTLCInfo {
prev_short_channel_id, prev_htlc_id, prev_funding_outpoint, prev_user_channel_id: _,
prev_short_channel_id, prev_htlc_id, prev_funding_outpoint, prev_user_channel_id,
forward_info: PendingHTLCInfo {
incoming_shared_secret, payment_hash, outgoing_amt_msat, outgoing_cltv_value,
routing: PendingHTLCRouting::Forward { onion_packet, .. }, skimmed_fee_msat, ..
Expand All @@ -3945,6 +3963,7 @@ where
log_trace!(self.logger, "Adding HTLC from short id {} with payment_hash {} to channel with short id {} after delay", prev_short_channel_id, log_bytes!(payment_hash.0), short_chan_id);
let htlc_source = HTLCSource::PreviousHopData(HTLCPreviousHopData {
short_channel_id: prev_short_channel_id,
user_channel_id: Some(prev_user_channel_id),
outpoint: prev_funding_outpoint,
htlc_id: prev_htlc_id,
incoming_packet_shared_secret: incoming_shared_secret,
Expand Down Expand Up @@ -4026,6 +4045,7 @@ where
let claimable_htlc = ClaimableHTLC {
prev_hop: HTLCPreviousHopData {
short_channel_id: prev_short_channel_id,
user_channel_id: Some(prev_user_channel_id),
outpoint: prev_funding_outpoint,
htlc_id: prev_htlc_id,
incoming_packet_shared_secret: incoming_shared_secret,
Expand Down Expand Up @@ -4055,6 +4075,7 @@ where
);
failed_forwards.push((HTLCSource::PreviousHopData(HTLCPreviousHopData {
short_channel_id: $htlc.prev_hop.short_channel_id,
user_channel_id: $htlc.prev_hop.user_channel_id,
outpoint: prev_funding_outpoint,
htlc_id: $htlc.prev_hop.htlc_id,
incoming_packet_shared_secret: $htlc.prev_hop.incoming_packet_shared_secret,
Expand Down Expand Up @@ -4786,7 +4807,7 @@ where
&self.pending_events, &self.logger)
{ self.push_pending_forwards_ev(); }
},
HTLCSource::PreviousHopData(HTLCPreviousHopData { ref short_channel_id, ref htlc_id, ref incoming_packet_shared_secret, ref phantom_shared_secret, ref outpoint }) => {
HTLCSource::PreviousHopData(HTLCPreviousHopData { ref short_channel_id, ref htlc_id, ref incoming_packet_shared_secret, ref phantom_shared_secret, ref outpoint, .. }) => {
log_trace!(self.logger, "Failing HTLC with payment_hash {} backwards from us with {:?}", log_bytes!(payment_hash.0), onion_error);
let err_packet = onion_error.get_encrypted_failure_packet(incoming_packet_shared_secret, phantom_shared_secret);

Expand Down Expand Up @@ -4873,9 +4894,11 @@ where
}
}

let htlcs = payment.htlcs.iter().map(events::ClaimedHTLC::from).collect();
let sender_intended_value = payment.htlcs.first().map(|htlc| htlc.total_msat);
let dup_purpose = claimable_payments.pending_claiming_payments.insert(payment_hash,
ClaimingPayment { amount_msat: payment.htlcs.iter().map(|source| source.value).sum(),
payment_purpose: payment.purpose, receiver_node_id,
payment_purpose: payment.purpose, receiver_node_id, htlcs, sender_intended_value
});
if dup_purpose.is_some() {
debug_assert!(false, "Shouldn't get a duplicate pending claim event ever");
Expand Down Expand Up @@ -5139,9 +5162,20 @@ where
match action {
MonitorUpdateCompletionAction::PaymentClaimed { payment_hash } => {
let payment = self.claimable_payments.lock().unwrap().pending_claiming_payments.remove(&payment_hash);
if let Some(ClaimingPayment { amount_msat, payment_purpose: purpose, receiver_node_id }) = payment {
if let Some(ClaimingPayment {
amount_msat,
payment_purpose: purpose,
receiver_node_id,
htlcs,
sender_intended_value: sender_intended_total_msat,
}) = payment {
self.pending_events.lock().unwrap().push_back((events::Event::PaymentClaimed {
payment_hash, purpose, amount_msat, receiver_node_id: Some(receiver_node_id),
payment_hash,
purpose,
amount_msat,
receiver_node_id: Some(receiver_node_id),
htlcs,
sender_intended_total_msat,
}, None));
}
},
Expand Down Expand Up @@ -6019,6 +6053,7 @@ where
log_info!(self.logger, "Failed to forward incoming HTLC: detected duplicate intercepted payment over short channel id {}", scid);
let htlc_source = HTLCSource::PreviousHopData(HTLCPreviousHopData {
short_channel_id: prev_short_channel_id,
user_channel_id: Some(prev_user_channel_id),
outpoint: prev_funding_outpoint,
htlc_id: prev_htlc_id,
incoming_packet_shared_secret: forward_info.incoming_shared_secret,
Expand Down Expand Up @@ -7145,6 +7180,7 @@ where
if height >= htlc.forward_info.outgoing_cltv_value - HTLC_FAIL_BACK_BUFFER {
let prev_hop_data = HTLCSource::PreviousHopData(HTLCPreviousHopData {
short_channel_id: htlc.prev_short_channel_id,
user_channel_id: Some(htlc.prev_user_channel_id),
htlc_id: htlc.prev_htlc_id,
incoming_packet_shared_secret: htlc.forward_info.incoming_shared_secret,
phantom_shared_secret: None,
Expand Down Expand Up @@ -7920,7 +7956,8 @@ impl_writeable_tlv_based!(HTLCPreviousHopData, {
(1, phantom_shared_secret, option),
(2, outpoint, required),
(4, htlc_id, required),
(6, incoming_packet_shared_secret, required)
(6, incoming_packet_shared_secret, required),
(7, user_channel_id, option),
});

impl Writeable for ClaimableHTLC {
Expand Down Expand Up @@ -9174,7 +9211,7 @@ where
.expect("Failed to get node_id for phantom node recipient");
receiver_node_id = Some(phantom_pubkey)
}
for claimable_htlc in payment.htlcs {
for claimable_htlc in &payment.htlcs {
claimable_amt_msat += claimable_htlc.value;

// Add a holding-cell claim of the payment to the Channel, which should be
Expand Down Expand Up @@ -9210,6 +9247,8 @@ where
payment_hash,
purpose: payment.purpose,
amount_msat: claimable_amt_msat,
htlcs: payment.htlcs.iter().map(events::ClaimedHTLC::from).collect(),
sender_intended_total_msat: payment.htlcs.first().map(|htlc| htlc.total_msat),
}, None));
}
}
Expand Down
50 changes: 44 additions & 6 deletions lightning/src/ln/functional_test_utils.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@ use crate::chain::{BestBlock, ChannelMonitorUpdateStatus, Confirm, Listen, Watch
use crate::sign::EntropySource;
use crate::chain::channelmonitor::ChannelMonitor;
use crate::chain::transaction::OutPoint;
use crate::events::{ClosureReason, Event, HTLCDestination, MessageSendEvent, MessageSendEventsProvider, PathFailure, PaymentPurpose, PaymentFailureReason};
use crate::events::{ClaimedHTLC, ClosureReason, Event, HTLCDestination, MessageSendEvent, MessageSendEventsProvider, PathFailure, PaymentPurpose, PaymentFailureReason};
use crate::events::bump_transaction::{BumpTransactionEventHandler, Wallet, WalletSource};
use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
use crate::ln::channelmanager::{self, AChannelManager, ChainParameters, ChannelManager, ChannelManagerReadArgs, RAACommitmentOrder, PaymentSendFailure, RecipientOnionFields, PaymentId, MIN_CLTV_EXPIRY_DELTA};
Expand Down Expand Up @@ -933,6 +933,21 @@ macro_rules! check_added_monitors {
}
}

/// Checks whether the claimed HTLC for the specified path has the correct channel information.
///
/// This will panic if the path is empty, if the HTLC's channel ID is not actually a channel that
/// connects the final two nodes in the path, or if the `user_channel_id` is incorrect.
pub fn check_claimed_htlc_channel<'a, 'b, 'c>(origin_node: &Node<'a, 'b, 'c>, path: &[&Node<'a, 'b, 'c>], htlc: &ClaimedHTLC) {
let mut nodes = path.iter().rev();
let dest = nodes.next().expect("path should have a destination").node;
let prev = nodes.next().unwrap_or(&origin_node).node;
let dest_channels = dest.list_channels();
let ch = dest_channels.iter().find(|ch| ch.channel_id == htlc.channel_id)
.expect("HTLC's channel should be one of destination node's channels");
assert_eq!(htlc.user_channel_id, ch.user_channel_id);
assert_eq!(ch.counterparty.node_id, prev.get_our_node_id());
}

pub fn _reload_node<'a, 'b, 'c>(node: &'a Node<'a, 'b, 'c>, default_config: UserConfig, chanman_encoded: &[u8], monitors_encoded: &[&[u8]]) -> TestChannelManager<'b, 'c> {
let mut monitors_read = Vec::with_capacity(monitors_encoded.len());
for encoded in monitors_encoded {
Expand Down Expand Up @@ -2284,11 +2299,34 @@ pub fn pass_claimed_payment_along_route<'a, 'b, 'c>(origin_node: &Node<'a, 'b, '
let claim_event = expected_paths[0].last().unwrap().node.get_and_clear_pending_events();
assert_eq!(claim_event.len(), 1);
match claim_event[0] {
Event::PaymentClaimed { purpose: PaymentPurpose::SpontaneousPayment(preimage), .. }|
Event::PaymentClaimed { purpose: PaymentPurpose::InvoicePayment { payment_preimage: Some(preimage), ..}, .. } =>
assert_eq!(preimage, our_payment_preimage),
Event::PaymentClaimed { purpose: PaymentPurpose::InvoicePayment { .. }, payment_hash, .. } =>
assert_eq!(&payment_hash.0, &Sha256::hash(&our_payment_preimage.0)[..]),
Event::PaymentClaimed {
purpose: PaymentPurpose::SpontaneousPayment(preimage),
amount_msat,
ref htlcs,
.. }
| Event::PaymentClaimed {
purpose: PaymentPurpose::InvoicePayment { payment_preimage: Some(preimage), ..},
ref htlcs,
amount_msat,
..
} => {
assert_eq!(preimage, our_payment_preimage);
assert_eq!(htlcs.len(), expected_paths.len()); // One per path.
assert_eq!(htlcs.iter().map(|h| h.value_msat).sum::<u64>(), amount_msat);
expected_paths.iter().zip(htlcs).for_each(|(path, htlc)| check_claimed_htlc_channel(origin_node, path, htlc));
},
Event::PaymentClaimed {
purpose: PaymentPurpose::InvoicePayment { .. },
payment_hash,
amount_msat,
ref htlcs,
..
} => {
assert_eq!(&payment_hash.0, &Sha256::hash(&our_payment_preimage.0)[..]);
assert_eq!(htlcs.len(), expected_paths.len()); // One per path.
assert_eq!(htlcs.iter().map(|h| h.value_msat).sum::<u64>(), amount_msat);
expected_paths.iter().zip(htlcs).for_each(|(path, htlc)| check_claimed_htlc_channel(origin_node, path, htlc));
}
_ => panic!(),
}

Expand Down

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