//! Creating blinded paths and related utilities live here.
+pub mod payment;
+pub(crate) mod message;
pub(crate) mod utils;
-use bitcoin::hashes::{Hash, HashEngine};
-use bitcoin::hashes::sha256::Hash as Sha256;
-use bitcoin::secp256k1::{self, PublicKey, Scalar, Secp256k1, SecretKey};
+use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey};
-use crate::sign::{EntropySource, NodeSigner, Recipient};
-use crate::onion_message::ControlTlvs;
use crate::ln::msgs::DecodeError;
-use crate::ln::onion_utils;
-use crate::util::chacha20poly1305rfc::{ChaChaPolyReadAdapter, ChaChaPolyWriteAdapter};
-use crate::util::ser::{FixedLengthReader, LengthReadableArgs, Readable, VecWriter, Writeable, Writer};
+use crate::offers::invoice::BlindedPayInfo;
+use crate::routing::gossip::{NodeId, ReadOnlyNetworkGraph};
+use crate::sign::EntropySource;
+use crate::util::ser::{Readable, Writeable, Writer};
-use core::mem;
-use core::ops::Deref;
-use crate::io::{self, Cursor};
+use crate::io;
use crate::prelude::*;
/// Onion messages and payments can be sent and received to blinded paths, which serve to hide the
#[derive(Clone, Debug, Hash, PartialEq, Eq)]
pub struct BlindedPath {
/// To send to a blinded path, the sender first finds a route to the unblinded
- /// `introduction_node_id`, which can unblind its [`encrypted_payload`] to find out the onion
+ /// `introduction_node`, which can unblind its [`encrypted_payload`] to find out the onion
/// message or payment's next hop and forward it along.
///
/// [`encrypted_payload`]: BlindedHop::encrypted_payload
- pub(crate) introduction_node_id: PublicKey,
+ pub introduction_node: IntroductionNode,
/// Used by the introduction node to decrypt its [`encrypted_payload`] to forward the onion
/// message or payment.
///
/// [`encrypted_payload`]: BlindedHop::encrypted_payload
- pub(crate) blinding_point: PublicKey,
+ pub blinding_point: PublicKey,
/// The hops composing the blinded path.
- pub(crate) blinded_hops: Vec<BlindedHop>,
+ 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.
+/// The unblinded node in a [`BlindedPath`].
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
+pub enum IntroductionNode {
+ /// The node id of the introduction node.
+ NodeId(PublicKey),
+ /// The short channel id of the channel leading to the introduction node. The [`Direction`]
+ /// identifies which side of the channel is the introduction node.
+ DirectedShortChannelId(Direction, u64),
+}
+
+/// The side of a channel that is the [`IntroductionNode`] in a [`BlindedPath`]. [BOLT 7] defines
+/// which nodes is which in the [`ChannelAnnouncement`] message.
+///
+/// [BOLT 7]: https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#the-channel_announcement-message
+/// [`ChannelAnnouncement`]: crate::ln::msgs::ChannelAnnouncement
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
+pub enum Direction {
+ /// The lesser node id when compared lexicographically in ascending order.
+ NodeOne,
+ /// The greater node id when compared lexicographically in ascending order.
+ NodeTwo,
+}
+
+/// 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.
- pub(crate) blinded_node_id: PublicKey,
- /// The encrypted payload intended for 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 [`BlindedPath`].
// The node sending to this blinded path will later encode this payload into the onion packet for
// this hop.
- pub(crate) encrypted_payload: Vec<u8>,
+ pub encrypted_payload: Vec<u8>,
}
impl BlindedPath {
+ /// Create a one-hop blinded path for a message.
+ pub fn one_hop_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ recipient_node_id: PublicKey, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+ ) -> Result<Self, ()> {
+ Self::new_for_message(&[recipient_node_id], entropy_source, secp_ctx)
+ }
+
/// Create a blinded path for an onion message, to be forwarded along `node_pks`. The last node
/// pubkey in `node_pks` will be the destination node.
///
- /// Errors if less than two hops are provided or if `node_pk`(s) are invalid.
+ /// Errors if no hops are provided or if `node_pk`(s) are invalid.
// TODO: make all payloads the same size with padding + add dummy hops
- pub fn new_for_message<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>
- (node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>) -> Result<Self, ()>
- {
- if node_pks.len() < 2 { return Err(()) }
+ pub fn new_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>
+ ) -> Result<Self, ()> {
+ if node_pks.is_empty() { return Err(()) }
let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
- let introduction_node_id = node_pks[0];
+ let introduction_node = IntroductionNode::NodeId(node_pks[0]);
Ok(BlindedPath {
- introduction_node_id,
+ introduction_node,
blinding_point: PublicKey::from_secret_key(secp_ctx, &blinding_secret),
- blinded_hops: blinded_message_hops(secp_ctx, node_pks, &blinding_secret).map_err(|_| ())?,
+ blinded_hops: message::blinded_hops(secp_ctx, node_pks, &blinding_secret).map_err(|_| ())?,
})
}
- // Advance the blinded onion message path by one hop, so make the second hop into the new
- // introduction node.
- pub(super) fn advance_message_path_by_one<NS: Deref, T: secp256k1::Signing + secp256k1::Verification>
- (&mut self, node_signer: &NS, secp_ctx: &Secp256k1<T>) -> Result<(), ()>
- where NS::Target: NodeSigner
- {
- let control_tlvs_ss = node_signer.ecdh(Recipient::Node, &self.blinding_point, None)?;
- let rho = onion_utils::gen_rho_from_shared_secret(&control_tlvs_ss.secret_bytes());
- let encrypted_control_tlvs = self.blinded_hops.remove(0).encrypted_payload;
- let mut s = Cursor::new(&encrypted_control_tlvs);
- let mut reader = FixedLengthReader::new(&mut s, encrypted_control_tlvs.len() as u64);
- match ChaChaPolyReadAdapter::read(&mut reader, rho) {
- Ok(ChaChaPolyReadAdapter { readable: ControlTlvs::Forward(ForwardTlvs {
- mut next_node_id, next_blinding_override,
- })}) => {
- let mut new_blinding_point = match next_blinding_override {
- Some(blinding_point) => blinding_point,
- None => {
- let blinding_factor = {
- let mut sha = Sha256::engine();
- sha.input(&self.blinding_point.serialize()[..]);
- sha.input(control_tlvs_ss.as_ref());
- Sha256::from_engine(sha).into_inner()
- };
- self.blinding_point.mul_tweak(secp_ctx, &Scalar::from_be_bytes(blinding_factor).unwrap())
- .map_err(|_| ())?
- }
- };
- mem::swap(&mut self.blinding_point, &mut new_blinding_point);
- mem::swap(&mut self.introduction_node_id, &mut next_node_id);
- Ok(())
- },
- _ => Err(())
- }
+ /// Create a one-hop blinded path for a payment.
+ pub fn one_hop_for_payment<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ payee_node_id: PublicKey, payee_tlvs: payment::ReceiveTlvs, min_final_cltv_expiry_delta: u16,
+ entropy_source: &ES, secp_ctx: &Secp256k1<T>
+ ) -> Result<(BlindedPayInfo, Self), ()> {
+ // This value is not considered in pathfinding for 1-hop blinded paths, because it's intended to
+ // be in relation to a specific channel.
+ let htlc_maximum_msat = u64::max_value();
+ Self::new_for_payment(
+ &[], payee_node_id, payee_tlvs, htlc_maximum_msat, min_final_cltv_expiry_delta,
+ entropy_source, secp_ctx
+ )
}
-}
-/// Construct blinded onion message hops for the given `unblinded_path`.
-fn blinded_message_hops<T: secp256k1::Signing + secp256k1::Verification>(
- secp_ctx: &Secp256k1<T>, unblinded_path: &[PublicKey], session_priv: &SecretKey
-) -> Result<Vec<BlindedHop>, secp256k1::Error> {
- let mut blinded_hops = Vec::with_capacity(unblinded_path.len());
-
- let mut prev_ss_and_blinded_node_id = None;
- utils::construct_keys_callback(secp_ctx, unblinded_path, None, session_priv, |blinded_node_id, _, _, encrypted_payload_ss, unblinded_pk, _| {
- if let Some((prev_ss, prev_blinded_node_id)) = prev_ss_and_blinded_node_id {
- if let Some(pk) = unblinded_pk {
- let payload = ForwardTlvs {
- next_node_id: pk,
- next_blinding_override: None,
- };
- blinded_hops.push(BlindedHop {
- blinded_node_id: prev_blinded_node_id,
- encrypted_payload: encrypt_payload(payload, prev_ss),
- });
- } else { debug_assert!(false); }
- }
- prev_ss_and_blinded_node_id = Some((encrypted_payload_ss, blinded_node_id));
- })?;
-
- if let Some((final_ss, final_blinded_node_id)) = prev_ss_and_blinded_node_id {
- let final_payload = ReceiveTlvs { path_id: None };
- blinded_hops.push(BlindedHop {
- blinded_node_id: final_blinded_node_id,
- encrypted_payload: encrypt_payload(final_payload, final_ss),
- });
- } else { debug_assert!(false) }
-
- Ok(blinded_hops)
-}
+ /// 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 + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ intermediate_nodes: &[payment::ForwardNode], payee_node_id: PublicKey,
+ payee_tlvs: payment::ReceiveTlvs, htlc_maximum_msat: u64, min_final_cltv_expiry_delta: u16,
+ entropy_source: &ES, secp_ctx: &Secp256k1<T>
+ ) -> Result<(BlindedPayInfo, Self), ()> {
+ let introduction_node = IntroductionNode::NodeId(
+ intermediate_nodes.first().map_or(payee_node_id, |n| n.node_id)
+ );
+ let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
+ let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
-/// Encrypt TLV payload to be used as a [`BlindedHop::encrypted_payload`].
-fn encrypt_payload<P: Writeable>(payload: P, encrypted_tlvs_ss: [u8; 32]) -> Vec<u8> {
- let mut writer = VecWriter(Vec::new());
- let write_adapter = ChaChaPolyWriteAdapter::new(encrypted_tlvs_ss, &payload);
- write_adapter.write(&mut writer).expect("In-memory writes cannot fail");
- writer.0
+ let blinded_payinfo = payment::compute_payinfo(
+ intermediate_nodes, &payee_tlvs, htlc_maximum_msat, min_final_cltv_expiry_delta
+ )?;
+ Ok((blinded_payinfo, BlindedPath {
+ introduction_node,
+ 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(|_| ())?,
+ }))
+ }
+
+ /// Returns the introduction [`NodeId`] of the blinded path, if it is publicly reachable (i.e.,
+ /// it is found in the network graph).
+ pub fn public_introduction_node_id<'a>(
+ &self, network_graph: &'a ReadOnlyNetworkGraph
+ ) -> Option<&'a NodeId> {
+ match &self.introduction_node {
+ IntroductionNode::NodeId(pubkey) => {
+ let node_id = NodeId::from_pubkey(pubkey);
+ network_graph.nodes().get_key_value(&node_id).map(|(key, _)| key)
+ },
+ IntroductionNode::DirectedShortChannelId(direction, scid) => {
+ network_graph
+ .channel(*scid)
+ .map(|c| match direction {
+ Direction::NodeOne => &c.node_one,
+ Direction::NodeTwo => &c.node_two,
+ })
+ },
+ }
+ }
}
impl Writeable for BlindedPath {
fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
- self.introduction_node_id.write(w)?;
+ match &self.introduction_node {
+ IntroductionNode::NodeId(pubkey) => pubkey.write(w)?,
+ IntroductionNode::DirectedShortChannelId(direction, scid) => {
+ match direction {
+ Direction::NodeOne => 0u8.write(w)?,
+ Direction::NodeTwo => 1u8.write(w)?,
+ }
+ scid.write(w)?;
+ },
+ }
+
self.blinding_point.write(w)?;
(self.blinded_hops.len() as u8).write(w)?;
for hop in &self.blinded_hops {
impl Readable for BlindedPath {
fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
- let introduction_node_id = Readable::read(r)?;
+ let mut first_byte: u8 = Readable::read(r)?;
+ let introduction_node = match first_byte {
+ 0 => IntroductionNode::DirectedShortChannelId(Direction::NodeOne, Readable::read(r)?),
+ 1 => IntroductionNode::DirectedShortChannelId(Direction::NodeTwo, Readable::read(r)?),
+ 2|3 => {
+ use io::Read;
+ let mut pubkey_read = core::slice::from_mut(&mut first_byte).chain(r.by_ref());
+ IntroductionNode::NodeId(Readable::read(&mut pubkey_read)?)
+ },
+ _ => return Err(DecodeError::InvalidValue),
+ };
let blinding_point = Readable::read(r)?;
let num_hops: u8 = Readable::read(r)?;
if num_hops == 0 { return Err(DecodeError::InvalidValue) }
blinded_hops.push(Readable::read(r)?);
}
Ok(BlindedPath {
- introduction_node_id,
+ introduction_node,
blinding_point,
blinded_hops,
})
encrypted_payload
});
-/// TLVs to encode in an intermediate onion message packet's hop data. When provided in a blinded
-/// route, they are encoded into [`BlindedHop::encrypted_payload`].
-pub(crate) struct ForwardTlvs {
- /// The node id of the next hop in the onion message's path.
- pub(super) next_node_id: PublicKey,
- /// Senders to a blinded path use this value to concatenate the route they find to the
- /// introduction node with the blinded path.
- pub(super) next_blinding_override: Option<PublicKey>,
-}
-
-/// Similar to [`ForwardTlvs`], but these TLVs are for the final node.
-pub(crate) struct ReceiveTlvs {
- /// If `path_id` is `Some`, it is used to identify the blinded path that this onion message is
- /// sending to. This is useful for receivers to check that said blinded path is being used in
- /// the right context.
- pub(super) path_id: Option<[u8; 32]>,
-}
-
-impl Writeable for ForwardTlvs {
- fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
- // TODO: write padding
- encode_tlv_stream!(writer, {
- (4, self.next_node_id, required),
- (8, self.next_blinding_override, option)
- });
- Ok(())
- }
-}
-
-impl Writeable for ReceiveTlvs {
- fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
- // TODO: write padding
- encode_tlv_stream!(writer, {
- (6, self.path_id, option),
- });
- Ok(())
+impl Direction {
+ /// Returns the [`NodeId`] from the inputs corresponding to the direction.
+ pub fn select_node_id<'a>(&self, node_a: &'a NodeId, node_b: &'a NodeId) -> &'a NodeId {
+ match self {
+ Direction::NodeOne => core::cmp::min(node_a, node_b),
+ Direction::NodeTwo => core::cmp::max(node_a, node_b),
+ }
}
}
projects / rust-lightning / blobdiff