X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fblinded_path%2Fmod.rs;h=927bbea9f6e99ab6e15db2cbb619af0e187060ec;hb=808a51e70105f61e999718c4306476386fe3680b;hp=6225f99869b9364c6fadd0f75f437bcafc95536d;hpb=fe5a076aa6aa535c441f56419a680f383fd24744;p=rust-lightning

diff --git a/lightning/src/blinded_path/mod.rs b/lightning/src/blinded_path/mod.rs
index 6225f998..927bbea9 100644
--- a/lightning/src/blinded_path/mod.rs
+++ b/lightning/src/blinded_path/mod.rs
@@ -9,13 +9,15 @@
 
 //! Creating blinded paths and related utilities live here.
 
+pub mod payment;
 pub(crate) mod message;
 pub(crate) mod utils;
 
 use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey};
 
-use crate::sign::EntropySource;
 use crate::ln::msgs::DecodeError;
+use crate::offers::invoice::BlindedPayInfo;
+use crate::sign::EntropySource;
 use crate::util::ser::{Readable, Writeable, Writer};
 
 use crate::io;
@@ -40,13 +42,14 @@ pub struct BlindedPath {
 	pub blinded_hops: Vec<BlindedHop>,
 }
 
-/// Used to construct the blinded hops portion of a blinded path. These hops cannot be identified
-/// by outside observers and thus can be used to hide the identity of the recipient.
+/// An encrypted payload and node id corresponding to a hop in a payment or onion message path, to
+/// be encoded in the sender's onion packet. These hops cannot be identified by outside observers
+/// and thus can be used to hide the identity of the recipient.
 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
 pub struct BlindedHop {
-	/// The blinded node id of this hop in a blinded path.
+	/// The blinded node id of this hop in a [`BlindedPath`].
 	pub blinded_node_id: PublicKey,
-	/// The encrypted payload intended for this hop in a blinded path.
+	/// The encrypted payload intended for this hop in a [`BlindedPath`].
 	// The node sending to this blinded path will later encode this payload into the onion packet for
 	// this hop.
 	pub encrypted_payload: Vec<u8>,
@@ -72,6 +75,33 @@ impl BlindedPath {
 			blinded_hops: message::blinded_hops(secp_ctx, node_pks, &blinding_secret).map_err(|_| ())?,
 		})
 	}
+
+	/// Create a blinded path for a payment, to be forwarded along `intermediate_nodes`.
+	///
+	/// Errors if:
+	/// * a provided node id is invalid
+	/// * [`BlindedPayInfo`] calculation results in an integer overflow
+	/// * any unknown features are required in the provided [`ForwardTlvs`]
+	///
+	/// [`ForwardTlvs`]: crate::blinded_path::payment::ForwardTlvs
+	//  TODO: make all payloads the same size with padding + add dummy hops
+	pub fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+		intermediate_nodes: &[payment::ForwardNode], payee_node_id: PublicKey,
+		payee_tlvs: payment::ReceiveTlvs, htlc_maximum_msat: u64, entropy_source: &ES,
+		secp_ctx: &Secp256k1<T>
+	) -> Result<(BlindedPayInfo, Self), ()> {
+		let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
+		let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
+
+		let blinded_payinfo = payment::compute_payinfo(intermediate_nodes, &payee_tlvs, htlc_maximum_msat)?;
+		Ok((blinded_payinfo, BlindedPath {
+			introduction_node_id: intermediate_nodes.first().map_or(payee_node_id, |n| n.node_id),
+			blinding_point: PublicKey::from_secret_key(secp_ctx, &blinding_secret),
+			blinded_hops: payment::blinded_hops(
+				secp_ctx, intermediate_nodes, payee_node_id, payee_tlvs, &blinding_secret
+			).map_err(|_| ())?,
+		}))
+	}
 }
 
 impl Writeable for BlindedPath {