X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fblinded_path%2Fmod.rs;h=daa9f033d94e4f0b5544c8cc71bb6e7523ca8acb;hb=7002180261d495f15c12f9a341af1e7dbcac2990;hp=2cd03b8b8f90e9fc1cd2068c61d4ce3cb8506ddf;hpb=f1761e06e6b44cedb1e1a9886b96c6723cdad2f3;p=rust-lightning diff --git a/lightning/src/blinded_path/mod.rs b/lightning/src/blinded_path/mod.rs index 2cd03b8b..daa9f033 100644 --- a/lightning/src/blinded_path/mod.rs +++ b/lightning/src/blinded_path/mod.rs @@ -9,22 +9,19 @@ //! 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::chain::keysinterface::{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 @@ -32,135 +29,165 @@ use crate::prelude::*; #[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, + pub blinded_hops: Vec, } -/// 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, + pub encrypted_payload: Vec, } impl BlindedPath { + /// Create a one-hop blinded path for a message. + pub fn one_hop_for_message( + recipient_node_id: PublicKey, entropy_source: &ES, secp_ctx: &Secp256k1 + ) -> Result { + 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 - (node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1) -> Result - { - if node_pks.len() < 2 { return Err(()) } + pub fn new_for_message( + node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1 + ) -> Result { + 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 - (&mut self, node_signer: &NS, secp_ctx: &Secp256k1) -> 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( + payee_node_id: PublicKey, payee_tlvs: payment::ReceiveTlvs, min_final_cltv_expiry_delta: u16, + entropy_source: &ES, secp_ctx: &Secp256k1 + ) -> 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( - secp_ctx: &Secp256k1, unblinded_path: &[PublicKey], session_priv: &SecretKey -) -> Result, 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( + 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 + ) -> 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(payload: P, encrypted_tlvs_ss: [u8; 32]) -> Vec { - 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(&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 { @@ -172,7 +199,17 @@ impl Writeable for BlindedPath { impl Readable for BlindedPath { fn read(r: &mut R) -> Result { - 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) } @@ -181,7 +218,7 @@ impl Readable for BlindedPath { blinded_hops.push(Readable::read(r)?); } Ok(BlindedPath { - introduction_node_id, + introduction_node, blinding_point, blinded_hops, }) @@ -193,41 +230,12 @@ impl_writeable!(BlindedHop, { 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, -} - -/// 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(&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(&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), + } } }