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Merge pull request #3303 from TheBlueMatt/2024-09-inbound-payment-id
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Add a `PaymentId` for inbound payments
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@tnull
tnull authored Sep 24, 2024
2 parents 23109b6 + aaf529d commit a0d0f02
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Showing 6 changed files with 128 additions and 24 deletions.
2 changes: 1 addition & 1 deletion fuzz/src/full_stack.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -666,7 +666,7 @@ pub fn do_test(mut data: &[u8], logger: &Arc<dyn Logger>) {
// Adding new calls to `EntropySource::get_secure_random_bytes` during startup can change all the
// keys subsequently generated in this test. Rather than regenerating all the messages manually,
// it's easier to just increment the counter here so the keys don't change.
keys_manager.counter.fetch_sub(3, Ordering::AcqRel);
keys_manager.counter.fetch_sub(4, Ordering::AcqRel);
let network_graph = Arc::new(NetworkGraph::new(network, Arc::clone(&logger)));
let gossip_sync =
Arc::new(P2PGossipSync::new(Arc::clone(&network_graph), None, Arc::clone(&logger)));
Expand Down
31 changes: 29 additions & 2 deletions lightning/src/events/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -749,6 +749,14 @@ pub enum Event {
///
/// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
claim_deadline: Option<u32>,
/// A unique ID describing this payment (derived from the list of HTLCs in the payment).
///
/// Payers may pay for the same [`PaymentHash`] multiple times (though this is unsafe and
/// an intermediary node may steal the funds). Thus, in order to accurately track when
/// payments are received and claimed, you should use this identifier.
///
/// Only filled in for payments received on LDK versions 0.1 and higher.
payment_id: Option<PaymentId>,
},
/// Indicates a payment has been claimed and we've received money!
///
Expand Down Expand Up @@ -796,6 +804,14 @@ pub enum Event {
///
/// Payments received on LDK versions prior to 0.0.124 will have this field unset.
onion_fields: Option<RecipientOnionFields>,
/// A unique ID describing this payment (derived from the list of HTLCs in the payment).
///
/// Payers may pay for the same [`PaymentHash`] multiple times (though this is unsafe and
/// an intermediary node may steal the funds). Thus, in order to accurately track when
/// payments are received and claimed, you should use this identifier.
///
/// Only filled in for payments received on LDK versions 0.1 and higher.
payment_id: Option<PaymentId>,
},
/// Indicates that a peer connection with a node is needed in order to send an [`OnionMessage`].
///
Expand Down Expand Up @@ -1432,7 +1448,7 @@ impl Writeable for Event {
},
&Event::PaymentClaimable { ref payment_hash, ref amount_msat, counterparty_skimmed_fee_msat,
ref purpose, ref receiver_node_id, ref via_channel_id, ref via_user_channel_id,
ref claim_deadline, ref onion_fields
ref claim_deadline, ref onion_fields, ref payment_id,
} => {
1u8.write(writer)?;
let mut payment_secret = None;
Expand Down Expand Up @@ -1478,6 +1494,7 @@ impl Writeable for Event {
(9, onion_fields, option),
(10, skimmed_fee_opt, option),
(11, payment_context, option),
(13, payment_id, option),
});
},
&Event::PaymentSent { ref payment_id, ref payment_preimage, ref payment_hash, ref fee_paid_msat } => {
Expand Down Expand Up @@ -1634,7 +1651,10 @@ 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, ref htlcs, ref sender_intended_total_msat, ref onion_fields } => {
&Event::PaymentClaimed { ref payment_hash, ref amount_msat, ref purpose,
ref receiver_node_id, ref htlcs, ref sender_intended_total_msat, ref onion_fields,
ref payment_id,
} => {
19u8.write(writer)?;
write_tlv_fields!(writer, {
(0, payment_hash, required),
Expand All @@ -1644,6 +1664,7 @@ impl Writeable for Event {
(5, *htlcs, optional_vec),
(7, sender_intended_total_msat, option),
(9, onion_fields, option),
(11, payment_id, option),
});
},
&Event::ProbeSuccessful { ref payment_id, ref payment_hash, ref path } => {
Expand Down Expand Up @@ -1767,6 +1788,7 @@ impl MaybeReadable for Event {
let mut via_user_channel_id = None;
let mut onion_fields = None;
let mut payment_context = None;
let mut payment_id = None;
read_tlv_fields!(reader, {
(0, payment_hash, required),
(1, receiver_node_id, option),
Expand All @@ -1780,6 +1802,7 @@ impl MaybeReadable for Event {
(9, onion_fields, option),
(10, counterparty_skimmed_fee_msat_opt, option),
(11, payment_context, option),
(13, payment_id, option),
});
let purpose = match payment_secret {
Some(secret) => PaymentPurpose::from_parts(payment_preimage, secret, payment_context),
Expand All @@ -1796,6 +1819,7 @@ impl MaybeReadable for Event {
via_user_channel_id,
claim_deadline,
onion_fields,
payment_id,
}))
};
f()
Expand Down Expand Up @@ -2037,6 +2061,7 @@ impl MaybeReadable for Event {
let mut htlcs: Option<Vec<ClaimedHTLC>> = Some(vec![]);
let mut sender_intended_total_msat: Option<u64> = None;
let mut onion_fields = None;
let mut payment_id = None;
read_tlv_fields!(reader, {
(0, payment_hash, required),
(1, receiver_node_id, option),
Expand All @@ -2045,6 +2070,7 @@ impl MaybeReadable for Event {
(5, htlcs, optional_vec),
(7, sender_intended_total_msat, option),
(9, onion_fields, option),
(11, payment_id, option),
});
Ok(Some(Event::PaymentClaimed {
receiver_node_id,
Expand All @@ -2054,6 +2080,7 @@ impl MaybeReadable for Event {
htlcs: htlcs.unwrap_or_default(),
sender_intended_total_msat,
onion_fields,
payment_id,
}))
};
f()
Expand Down
84 changes: 76 additions & 8 deletions lightning/src/ln/channelmanager.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@ use bitcoin::constants::ChainHash;
use bitcoin::key::constants::SECRET_KEY_SIZE;
use bitcoin::network::Network;

use bitcoin::hashes::Hash;
use bitcoin::hashes::{Hash, HashEngine, HmacEngine};
use bitcoin::hashes::hmac::Hmac;
use bitcoin::hashes::sha256::Hash as Sha256;
use bitcoin::hash_types::{BlockHash, Txid};
Expand Down Expand Up @@ -369,6 +369,7 @@ pub(crate) struct HTLCPreviousHopData {
counterparty_node_id: Option<PublicKey>,
}

#[derive(PartialEq, Eq)]
enum OnionPayload {
/// Indicates this incoming onion payload is for the purpose of paying an invoice.
Invoice {
Expand All @@ -381,6 +382,7 @@ enum OnionPayload {
}

/// HTLCs that are to us and can be failed/claimed by the user
#[derive(PartialEq, Eq)]
struct ClaimableHTLC {
prev_hop: HTLCPreviousHopData,
cltv_expiry: u32,
Expand Down Expand Up @@ -412,6 +414,23 @@ impl From<&ClaimableHTLC> for events::ClaimedHTLC {
}
}

impl PartialOrd for ClaimableHTLC {
fn partial_cmp(&self, other: &ClaimableHTLC) -> Option<cmp::Ordering> {
Some(self.cmp(other))
}
}
impl Ord for ClaimableHTLC {
fn cmp(&self, other: &ClaimableHTLC) -> cmp::Ordering {
let res = (self.prev_hop.channel_id, self.prev_hop.htlc_id).cmp(
&(other.prev_hop.channel_id, other.prev_hop.htlc_id)
);
if res.is_eq() {
debug_assert!(self == other, "ClaimableHTLCs from the same source should be identical");
}
res
}
}

/// A trait defining behavior for creating and verifing the HMAC for authenticating a given data.
pub trait Verification {
/// Constructs an HMAC to include in [`OffersContext`] for the data along with the given
Expand Down Expand Up @@ -492,6 +511,22 @@ impl Verification for PaymentId {
}
}

impl PaymentId {
fn for_inbound_from_htlcs<I: Iterator<Item=(ChannelId, u64)>>(key: &[u8; 32], htlcs: I) -> PaymentId {
let mut prev_pair = None;
let mut hasher = HmacEngine::new(key);
for (channel_id, htlc_id) in htlcs {
hasher.input(&channel_id.0);
hasher.input(&htlc_id.to_le_bytes());
if let Some(prev) = prev_pair {
debug_assert!(prev < (channel_id, htlc_id), "HTLCs should be sorted");
}
prev_pair = Some((channel_id, htlc_id));
}
PaymentId(Hmac::<Sha256>::from_engine(hasher).to_byte_array())
}
}

impl Writeable for PaymentId {
fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
self.0.write(w)
Expand Down Expand Up @@ -765,6 +800,7 @@ struct ClaimingPayment {
htlcs: Vec<events::ClaimedHTLC>,
sender_intended_value: Option<u64>,
onion_fields: Option<RecipientOnionFields>,
payment_id: Option<PaymentId>,
}
impl_writeable_tlv_based!(ClaimingPayment, {
(0, amount_msat, required),
Expand All @@ -773,6 +809,7 @@ impl_writeable_tlv_based!(ClaimingPayment, {
(5, htlcs, optional_vec),
(7, sender_intended_value, option),
(9, onion_fields, option),
(11, payment_id, option),
});

struct ClaimablePayment {
Expand All @@ -781,6 +818,15 @@ struct ClaimablePayment {
htlcs: Vec<ClaimableHTLC>,
}

impl ClaimablePayment {
fn inbound_payment_id(&self, secret: &[u8; 32]) -> PaymentId {
PaymentId::for_inbound_from_htlcs(
secret,
self.htlcs.iter().map(|htlc| (htlc.prev_hop.channel_id, htlc.prev_hop.htlc_id))
)
}
}

/// Represent the channel funding transaction type.
enum FundingType {
/// This variant is useful when we want LDK to validate the funding transaction and
Expand Down Expand Up @@ -2283,6 +2329,9 @@ where
/// keeping additional state.
probing_cookie_secret: [u8; 32],

/// When generating [`PaymentId`]s for inbound payments, we HMAC the HTLCs with this secret.
inbound_payment_id_secret: [u8; 32],

/// The highest block timestamp we've seen, which is usually a good guess at the current time.
/// Assuming most miners are generating blocks with reasonable timestamps, this shouldn't be
/// very far in the past, and can only ever be up to two hours in the future.
Expand Down Expand Up @@ -3176,6 +3225,7 @@ where
fake_scid_rand_bytes: entropy_source.get_secure_random_bytes(),

probing_cookie_secret: entropy_source.get_secure_random_bytes(),
inbound_payment_id_secret: entropy_source.get_secure_random_bytes(),

highest_seen_timestamp: AtomicUsize::new(current_timestamp as usize),

Expand Down Expand Up @@ -5769,10 +5819,9 @@ where
} else {
claimable_payment.onion_fields = Some(onion_fields);
}
let ref mut htlcs = &mut claimable_payment.htlcs;
let mut total_value = claimable_htlc.sender_intended_value;
let mut earliest_expiry = claimable_htlc.cltv_expiry;
for htlc in htlcs.iter() {
for htlc in claimable_payment.htlcs.iter() {
total_value += htlc.sender_intended_value;
earliest_expiry = cmp::min(earliest_expiry, htlc.cltv_expiry);
if htlc.total_msat != claimable_htlc.total_msat {
Expand All @@ -5794,13 +5843,18 @@ where
#[allow(unused_assignments)] {
committed_to_claimable = true;
}
htlcs.push(claimable_htlc);
let amount_msat = htlcs.iter().map(|htlc| htlc.value).sum();
htlcs.iter_mut().for_each(|htlc| htlc.total_value_received = Some(amount_msat));
let counterparty_skimmed_fee_msat = htlcs.iter()
claimable_payment.htlcs.push(claimable_htlc);
let amount_msat =
claimable_payment.htlcs.iter().map(|htlc| htlc.value).sum();
claimable_payment.htlcs.iter_mut()
.for_each(|htlc| htlc.total_value_received = Some(amount_msat));
let counterparty_skimmed_fee_msat = claimable_payment.htlcs.iter()
.map(|htlc| htlc.counterparty_skimmed_fee_msat.unwrap_or(0)).sum();
debug_assert!(total_value.saturating_sub(amount_msat) <=
counterparty_skimmed_fee_msat);
claimable_payment.htlcs.sort();
let payment_id =
claimable_payment.inbound_payment_id(&self.inbound_payment_id_secret);
new_events.push_back((events::Event::PaymentClaimable {
receiver_node_id: Some(receiver_node_id),
payment_hash,
Expand All @@ -5811,13 +5865,14 @@ where
via_user_channel_id: Some(prev_user_channel_id),
claim_deadline: Some(earliest_expiry - HTLC_FAIL_BACK_BUFFER),
onion_fields: claimable_payment.onion_fields.clone(),
payment_id: Some(payment_id),
}, None));
payment_claimable_generated = true;
} else {
// Nothing to do - we haven't reached the total
// payment value yet, wait until we receive more
// MPP parts.
htlcs.push(claimable_htlc);
claimable_payment.htlcs.push(claimable_htlc);
#[allow(unused_assignments)] {
committed_to_claimable = true;
}
Expand Down Expand Up @@ -6614,6 +6669,7 @@ where
}
}

let payment_id = payment.inbound_payment_id(&self.inbound_payment_id_secret);
let claiming_payment = claimable_payments.pending_claiming_payments
.entry(payment_hash)
.and_modify(|_| {
Expand All @@ -6631,6 +6687,7 @@ where
htlcs,
sender_intended_value,
onion_fields: payment.onion_fields,
payment_id: Some(payment_id),
}
});

Expand Down Expand Up @@ -7148,6 +7205,7 @@ where
htlcs,
sender_intended_value: sender_intended_total_msat,
onion_fields,
payment_id,
}) = payment {
self.pending_events.lock().unwrap().push_back((events::Event::PaymentClaimed {
payment_hash,
Expand All @@ -7157,6 +7215,7 @@ where
htlcs,
sender_intended_total_msat,
onion_fields,
payment_id,
}, None));
}
},
Expand Down Expand Up @@ -12428,6 +12487,7 @@ where
let mut events_override = None;
let mut in_flight_monitor_updates: Option<HashMap<(PublicKey, OutPoint), Vec<ChannelMonitorUpdate>>> = None;
let mut decode_update_add_htlcs: Option<HashMap<u64, Vec<msgs::UpdateAddHTLC>>> = None;
let mut inbound_payment_id_secret = None;
read_tlv_fields!(reader, {
(1, pending_outbound_payments_no_retry, option),
(2, pending_intercepted_htlcs, option),
Expand All @@ -12442,6 +12502,7 @@ where
(11, probing_cookie_secret, option),
(13, claimable_htlc_onion_fields, optional_vec),
(14, decode_update_add_htlcs, option),
(15, inbound_payment_id_secret, option),
});
let mut decode_update_add_htlcs = decode_update_add_htlcs.unwrap_or_else(|| new_hash_map());
if fake_scid_rand_bytes.is_none() {
Expand All @@ -12452,6 +12513,10 @@ where
probing_cookie_secret = Some(args.entropy_source.get_secure_random_bytes());
}

if inbound_payment_id_secret.is_none() {
inbound_payment_id_secret = Some(args.entropy_source.get_secure_random_bytes());
}

if let Some(events) = events_override {
pending_events_read = events;
}
Expand Down Expand Up @@ -12900,6 +12965,7 @@ where
previous_hop_monitor.provide_payment_preimage(&payment_hash, &payment_preimage, &args.tx_broadcaster, &bounded_fee_estimator, &args.logger);
}
}
let payment_id = payment.inbound_payment_id(&inbound_payment_id_secret.unwrap());
pending_events_read.push_back((events::Event::PaymentClaimed {
receiver_node_id,
payment_hash,
Expand All @@ -12908,6 +12974,7 @@ where
htlcs: payment.htlcs.iter().map(events::ClaimedHTLC::from).collect(),
sender_intended_total_msat: payment.htlcs.first().map(|htlc| htlc.total_msat),
onion_fields: payment.onion_fields,
payment_id: Some(payment_id),
}, None));
}
}
Expand Down Expand Up @@ -12978,6 +13045,7 @@ where
fake_scid_rand_bytes: fake_scid_rand_bytes.unwrap(),

probing_cookie_secret: probing_cookie_secret.unwrap(),
inbound_payment_id_secret: inbound_payment_id_secret.unwrap(),

our_network_pubkey,
secp_ctx,
Expand Down
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