f remove offer_id from held htlc avail message context

Author: valentinewallace

lightning/src/blinded_path/message.rs

@@ -25,7 +25,6 @@ use crate::ln::msgs::DecodeError;
 use crate::ln::onion_utils;
 use crate::types::payment::PaymentHash;
 use crate::offers::nonce::Nonce;
-use crate::offers::offer::OfferId;
 use crate::onion_message::packet::ControlTlvs;
 use crate::routing::gossip::{NodeId, ReadOnlyNetworkGraph};
 use crate::sign::{EntropySource, NodeSigner, Recipient};
@@ -408,12 +407,6 @@ pub enum AsyncPaymentsContext {
 	///
 	/// [`HeldHtlcAvailable`]: crate::onion_message::async_payments::HeldHtlcAvailable
 	InboundPayment {
-		/// The ID of the [`Offer`] that this [`BlindedMessagePath`]'s static invoice corresponds to.
-		/// Useful to authenticate that this blinded path was created by us for asynchronously paying
-		/// one of our offers.
-		///
-		/// [`Offer`]: crate::offers::offer::Offer
-		offer_id: OfferId,
 		/// A nonce used for authenticating that a [`HeldHtlcAvailable`] message is valid for a
 		/// preceding static invoice.
 		///
@@ -457,9 +450,8 @@ impl_writeable_tlv_based_enum!(AsyncPaymentsContext,
 		(4, hmac, required),
 	},
 	(1, InboundPayment) => {
-		(0, offer_id, required),
-		(2, nonce, required),
-		(4, hmac, required),
+		(0, nonce, required),
+		(2, hmac, required),
 	},
 );
 

lightning/src/offers/offer.rs

@@ -98,13 +98,6 @@ use crate::offers::signer::{Metadata, MetadataMaterial, self};
 use crate::util::ser::{CursorReadable, HighZeroBytesDroppedBigSize, Readable, WithoutLength, Writeable, Writer};
 use crate::util::string::PrintableString;
 
-#[cfg(async_payments)]
-use {
-	bitcoin::hashes::hmac::Hmac,
-	bitcoin::hashes::sha256::Hash as Sha256,
-	crate::ln::inbound_payment,
-};
-
 #[cfg(not(c_bindings))]
 use {
 	crate::offers::invoice_request::InvoiceRequestBuilder,
@@ -141,15 +134,6 @@ impl OfferId {
 		let tagged_hash = TaggedHash::from_tlv_stream(Self::ID_TAG, tlv_stream);
 		Self(tagged_hash.to_bytes())
 	}
-
-	/// Constructs an HMAC to include in [`AsyncPaymentsContext::InboundPayment`] for the offer id
-	/// along with the given [`Nonce`].
-	#[cfg(async_payments)]
-	pub fn hmac_for_static_invoice(
-		&self, nonce: Nonce, expanded_key: &inbound_payment::ExpandedKey,
-	) -> Hmac<Sha256> {
-		signer::hmac_for_static_invoice_offer_id(*self, nonce, expanded_key)
-	}
 }
 
 impl Borrow<[u8]> for OfferId {

lightning/src/offers/signer.rs

@@ -20,8 +20,6 @@ use crate::ln::channelmanager::PaymentId;
 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN};
 use crate::offers::merkle::TlvRecord;
 use crate::offers::nonce::Nonce;
-#[cfg(async_payments)]
-use crate::offers::offer::OfferId;
 use crate::util::ser::Writeable;
 
 use crate::prelude::*;
@@ -48,9 +46,10 @@ const ASYNC_PAYMENT_ID_HMAC_INPUT: &[u8; 16] = &[6; 16];
 // HMAC input for a `PaymentHash`. The HMAC is used in `OffersContext::InboundPayment`.
 const PAYMENT_HASH_HMAC_INPUT: &[u8; 16] = &[7; 16];
 
-// HMAC input for an `OfferId`. The HMAC is used in `AsyncPaymentsContext::InboundPayment`.
+// HMAC input used in `AsyncPaymentsContext::InboundPayment` to authenticate inbound
+// held_htlc_available onion messages.
 #[cfg(async_payments)]
-const ASYNC_PAYMENT_OFFER_ID_HMAC_INPUT: &[u8; 16] = &[8; 16];
+const ASYNC_PAYMENTS_HELD_HTLC_HMAC_INPUT: &[u8; 16] = &[8; 16];
 
 /// Message metadata which possibly is derived from [`MetadataMaterial`] such that it can be
 /// verified.
@@ -467,15 +466,14 @@ fn hmac_for_payment_id(
 }
 
 #[cfg(async_payments)]
-pub(crate) fn hmac_for_static_invoice_offer_id(
-	offer_id: OfferId, nonce: Nonce, expanded_key: &ExpandedKey,
+pub(crate) fn hmac_for_held_htlc_available_context(
+	nonce: Nonce, expanded_key: &ExpandedKey,
 ) -> Hmac<Sha256> {
-	const IV_BYTES: &[u8; IV_LEN] = b"LDK Offer ID ~~~";
+	const IV_BYTES: &[u8; IV_LEN] = b"LDK Held HTLC OM";
 	let mut hmac = expanded_key.hmac_for_offer();
 	hmac.input(IV_BYTES);
 	hmac.input(&nonce.0);
-	hmac.input(ASYNC_PAYMENT_OFFER_ID_HMAC_INPUT);
-	hmac.input(&offer_id.0);
+	hmac.input(ASYNC_PAYMENTS_HELD_HTLC_HMAC_INPUT);
 
 	Hmac::from_engine(hmac)
 }