Add offer_id

Author: jkczyz

lightning/src/offers/merkle.rs

@@ -14,7 +14,7 @@ use util::ser::{BigSize, Readable};
 
 const SIGNATURE_TYPES: core::ops::RangeInclusive<u64> = 240..=1000;
 
-pub(super) fn tagged_root_hash(tag: sha256::Hash, data: &[u8]) -> sha256::Hash {
+pub(super) fn root_hash(data: &[u8]) -> sha256::Hash {
 	let mut engine = sha256::Hash::engine();
 	engine.input("LnAll".as_bytes());
 	for record in TlvStream::new(&data[..]) {
@@ -48,7 +48,15 @@ pub(super) fn tagged_root_hash(tag: sha256::Hash, data: &[u8]) -> sha256::Hash {
 	}
 
 	// TODO: Can we ever have zero leaves?
-	tagged_hash(tag, leaves.first().unwrap())
+	*leaves.first().unwrap()
+}
+
+pub(super) fn tagged_hash<T: AsRef<[u8]>>(tag: sha256::Hash, msg: T) -> sha256::Hash {
+	let mut engine = sha256::Hash::engine();
+	engine.input(tag.as_ref());
+	engine.input(tag.as_ref());
+	engine.input(msg.as_ref());
+	sha256::Hash::from_engine(engine)
 }
 
 fn tagged_branch_hash(tag: sha256::Hash, leaf1: sha256::Hash, leaf2: sha256::Hash) -> sha256::Hash {
@@ -65,14 +73,6 @@ fn tagged_branch_hash(tag: sha256::Hash, leaf1: sha256::Hash, leaf2: sha256::Has
 	sha256::Hash::from_engine(engine)
 }
 
-fn tagged_hash<T: AsRef<[u8]>>(tag: sha256::Hash, msg: T) -> sha256::Hash {
-	let mut engine = sha256::Hash::engine();
-	engine.input(tag.as_ref());
-	engine.input(tag.as_ref());
-	engine.input(msg.as_ref());
-	sha256::Hash::from_engine(engine)
-}
-
 struct TlvStream<'a> {
 	data: ::io::Cursor<&'a [u8]>,
 }

lightning/src/offers/mod.rs

@@ -36,6 +36,7 @@ mod merkle;
 ///
 #[derive(Clone, Debug)]
 pub struct Offer {
+	id: sha256::Hash,
 	chains: Option<Vec<BlockHash>>,
 	amount: Option<Amount>,
 	description: String,
@@ -51,6 +52,11 @@ pub struct Offer {
 }
 
 impl Offer {
+	///
+	pub fn id(&self) -> sha256::Hash {
+		self.id
+	}
+
 	///
 	pub fn chain(&self) -> BlockHash {
 		self.chains
@@ -417,15 +423,16 @@ impl TryFrom<ParsedOffer> for Offer {
 			(Some(_), _) => Some(SendInvoice { refund_for }),
 		};
 
-
+		let id = merkle::root_hash(&data);
 		if let Some(signature) = &signature {
 			let tag = sha256::Hash::hash(concat!("lightning", "offer", "signature").as_bytes());
-			let message = Message::from_slice(&merkle::tagged_root_hash(tag, &data)).unwrap();
+			let message = Message::from_slice(&merkle::tagged_hash(tag, id)).unwrap();
 			let secp_ctx = Secp256k1::verification_only();
 			secp_ctx.verify_schnorr(signature, &message, &destination.node_id())?;
 		}
 
 		Ok(Offer {
+			id,
 			chains,
 			amount,
 			description: description.unwrap().0,