//! LDK sends, receives, and forwards onion messages via the [`OnionMessenger`]. See its docs for
//! more information.
-use bitcoin::secp256k1::{self, PublicKey, Secp256k1};
+use bitcoin::hashes::{Hash, HashEngine};
+use bitcoin::hashes::hmac::{Hmac, HmacEngine};
+use bitcoin::hashes::sha256::Hash as Sha256;
+use bitcoin::secp256k1::{self, PublicKey, Scalar, Secp256k1, SecretKey};
-use chain::keysinterface::{InMemorySigner, KeysInterface, KeysManager, Sign};
-use ln::msgs;
-use util::logger::Logger;
+use crate::chain::keysinterface::{KeysInterface, KeysManager, Recipient};
+use crate::ln::features::{InitFeatures, NodeFeatures};
+use crate::ln::msgs::{self, OnionMessageHandler};
+use crate::ln::onion_utils;
+use crate::ln::peer_handler::IgnoringMessageHandler;
+use super::blinded_path::{BlindedPath, ForwardTlvs, ReceiveTlvs};
+use super::packet::{CustomOnionMessageContents, OnionMessageContents};
+use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
+use super::utils;
+use crate::util::events::OnionMessageProvider;
+use crate::util::logger::Logger;
+use crate::util::ser::Writeable;
use core::ops::Deref;
-use sync::{Arc, Mutex};
-use prelude::*;
+use crate::io;
+use crate::sync::{Arc, Mutex};
+use crate::prelude::*;
/// A sender, receiver and forwarder of onion messages. In upcoming releases, this object will be
-/// used to retrieve invoices and fulfill invoice requests from [offers].
+/// used to retrieve invoices and fulfill invoice requests from [offers]. Currently, only sending
+/// and receiving custom onion messages is supported.
+///
+/// # Example
+///
+/// ```
+/// # extern crate bitcoin;
+/// # use bitcoin::hashes::_export::_core::time::Duration;
+/// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
+/// # use lightning::chain::keysinterface::{InMemorySigner, KeysManager, KeysInterface};
+/// # use lightning::ln::msgs::DecodeError;
+/// # use lightning::ln::peer_handler::IgnoringMessageHandler;
+/// # use lightning::onion_message::blinded_path::BlindedPath;
+/// # use lightning::onion_message::messenger::{CustomOnionMessageContents, Destination, OnionMessageContents, OnionMessenger};
+/// # use lightning::util::logger::{Logger, Record};
+/// # use lightning::util::ser::{Writeable, Writer};
+/// # use lightning::io;
+/// # use std::sync::Arc;
+/// # struct FakeLogger {};
+/// # impl Logger for FakeLogger {
+/// # fn log(&self, record: &Record) { unimplemented!() }
+/// # }
+/// # let seed = [42u8; 32];
+/// # let time = Duration::from_secs(123456);
+/// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
+/// # let logger = Arc::new(FakeLogger {});
+/// # let node_secret = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
+/// # let secp_ctx = Secp256k1::new();
+/// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
+/// # let (hop_node_id2, hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1, hop_node_id1);
+/// # let destination_node_id = hop_node_id1;
+/// # let your_custom_message_handler = IgnoringMessageHandler {};
+/// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
+/// // ChannelManager.
+/// let onion_messenger = OnionMessenger::new(&keys_manager, logger, your_custom_message_handler);
+///
+/// # struct YourCustomMessage {}
+/// impl Writeable for YourCustomMessage {
+/// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+/// # Ok(())
+/// // Write your custom onion message to `w`
+/// }
+/// }
+/// impl CustomOnionMessageContents for YourCustomMessage {
+/// fn tlv_type(&self) -> u64 {
+/// # let your_custom_message_type = 42;
+/// your_custom_message_type
+/// }
+/// }
+/// // Send a custom onion message to a node id.
+/// let intermediate_hops = [hop_node_id1, hop_node_id2];
+/// let reply_path = None;
+/// # let your_custom_message = YourCustomMessage {};
+/// let message = OnionMessageContents::Custom(your_custom_message);
+/// onion_messenger.send_onion_message(&intermediate_hops, Destination::Node(destination_node_id), message, reply_path);
+///
+/// // Create a blinded path to yourself, for someone to send an onion message to.
+/// # let your_node_id = hop_node_id1;
+/// let hops = [hop_node_id3, hop_node_id4, your_node_id];
+/// let blinded_path = BlindedPath::new(&hops, &keys_manager, &secp_ctx).unwrap();
+///
+/// // Send a custom onion message to a blinded path.
+/// # let intermediate_hops = [hop_node_id1, hop_node_id2];
+/// let reply_path = None;
+/// # let your_custom_message = YourCustomMessage {};
+/// let message = OnionMessageContents::Custom(your_custom_message);
+/// onion_messenger.send_onion_message(&intermediate_hops, Destination::BlindedPath(blinded_path), message, reply_path);
+/// ```
///
/// [offers]: <https://github.com/lightning/bolts/pull/798>
-pub struct OnionMessenger<Signer: Sign, K: Deref, L: Deref>
- where K::Target: KeysInterface<Signer = Signer>,
+/// [`OnionMessenger`]: crate::onion_message::OnionMessenger
+pub struct OnionMessenger<K: Deref, L: Deref, CMH: Deref>
+ where K::Target: KeysInterface,
L::Target: Logger,
+ CMH:: Target: CustomOnionMessageHandler,
{
keys_manager: K,
logger: L,
- pending_messages: Mutex<HashMap<PublicKey, Vec<msgs::OnionMessage>>>,
+ pending_messages: Mutex<HashMap<PublicKey, VecDeque<msgs::OnionMessage>>>,
secp_ctx: Secp256k1<secp256k1::All>,
+ custom_handler: CMH,
// Coming soon:
// invoice_handler: InvoiceHandler,
- // custom_handler: CustomHandler, // handles custom onion messages
}
-impl<Signer: Sign, K: Deref, L: Deref> OnionMessenger<Signer, K, L>
- where K::Target: KeysInterface<Signer = Signer>,
+/// The destination of an onion message.
+pub enum Destination {
+ /// We're sending this onion message to a node.
+ Node(PublicKey),
+ /// We're sending this onion message to a blinded path.
+ BlindedPath(BlindedPath),
+}
+
+impl Destination {
+ pub(super) fn num_hops(&self) -> usize {
+ match self {
+ Destination::Node(_) => 1,
+ Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
+ }
+ }
+}
+
+/// Errors that may occur when [sending an onion message].
+///
+/// [sending an onion message]: OnionMessenger::send_onion_message
+#[derive(Debug, PartialEq, Eq)]
+pub enum SendError {
+ /// Errored computing onion message packet keys.
+ Secp256k1(secp256k1::Error),
+ /// Because implementations such as Eclair will drop onion messages where the message packet
+ /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
+ TooBigPacket,
+ /// The provided [`Destination`] was an invalid [`BlindedPath`], due to having fewer than two
+ /// blinded hops.
+ TooFewBlindedHops,
+ /// Our next-hop peer was offline or does not support onion message forwarding.
+ InvalidFirstHop,
+ /// Onion message contents must have a TLV type >= 64.
+ InvalidMessage,
+ /// Our next-hop peer's buffer was full or our total outbound buffer was full.
+ BufferFull,
+ /// Failed to retrieve our node id from the provided [`KeysInterface`].
+ ///
+ /// [`KeysInterface`]: crate::chain::keysinterface::KeysInterface
+ GetNodeIdFailed,
+ /// We attempted to send to a blinded path where we are the introduction node, and failed to
+ /// advance the blinded path to make the second hop the new introduction node. Either
+ /// [`KeysInterface::ecdh`] failed, we failed to tweak the current blinding point to get the
+ /// new blinding point, or we were attempting to send to ourselves.
+ BlindedPathAdvanceFailed,
+}
+
+/// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
+/// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
+/// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
+/// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
+/// message types.
+///
+/// See [`OnionMessenger`] for example usage.
+///
+/// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
+/// [`CustomMessage`]: Self::CustomMessage
+pub trait CustomOnionMessageHandler {
+ /// The message known to the handler. To support multiple message types, you may want to make this
+ /// an enum with a variant for each supported message.
+ type CustomMessage: CustomOnionMessageContents;
+ /// Called with the custom message that was received.
+ fn handle_custom_message(&self, msg: Self::CustomMessage);
+ /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
+ /// message type is unknown.
+ fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
+}
+
+impl<K: Deref, L: Deref, CMH: Deref> OnionMessenger<K, L, CMH>
+ where K::Target: KeysInterface,
L::Target: Logger,
+ CMH::Target: CustomOnionMessageHandler,
{
/// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
/// their respective handlers.
- pub fn new(keys_manager: K, logger: L) -> Self {
+ pub fn new(keys_manager: K, logger: L, custom_handler: CMH) -> Self {
let mut secp_ctx = Secp256k1::new();
secp_ctx.seeded_randomize(&keys_manager.get_secure_random_bytes());
OnionMessenger {
pending_messages: Mutex::new(HashMap::new()),
secp_ctx,
logger,
+ custom_handler,
}
}
+
+ /// Send an onion message with contents `message` to `destination`, routing it through `intermediate_nodes`.
+ /// See [`OnionMessenger`] for example usage.
+ pub fn send_onion_message<T: CustomOnionMessageContents>(&self, intermediate_nodes: &[PublicKey], mut destination: Destination, message: OnionMessageContents<T>, reply_path: Option<BlindedPath>) -> Result<(), SendError> {
+ if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
+ if blinded_hops.len() < 2 {
+ return Err(SendError::TooFewBlindedHops);
+ }
+ }
+ let OnionMessageContents::Custom(ref msg) = message;
+ if msg.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
+
+ // If we are sending straight to a blinded path and we are the introduction node, we need to
+ // advance the blinded path by 1 hop so the second hop is the new introduction node.
+ if intermediate_nodes.len() == 0 {
+ if let Destination::BlindedPath(ref mut blinded_path) = destination {
+ let our_node_id = self.keys_manager.get_node_id(Recipient::Node)
+ .map_err(|()| SendError::GetNodeIdFailed)?;
+ if blinded_path.introduction_node_id == our_node_id {
+ blinded_path.advance_by_one(&self.keys_manager, &self.secp_ctx)
+ .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
+ }
+ }
+ }
+
+ let blinding_secret_bytes = self.keys_manager.get_secure_random_bytes();
+ let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
+ let (introduction_node_id, blinding_point) = if intermediate_nodes.len() != 0 {
+ (intermediate_nodes[0], PublicKey::from_secret_key(&self.secp_ctx, &blinding_secret))
+ } else {
+ match destination {
+ Destination::Node(pk) => (pk, PublicKey::from_secret_key(&self.secp_ctx, &blinding_secret)),
+ Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
+ (introduction_node_id, blinding_point),
+ }
+ };
+ let (packet_payloads, packet_keys) = packet_payloads_and_keys(
+ &self.secp_ctx, intermediate_nodes, destination, message, reply_path, &blinding_secret)
+ .map_err(|e| SendError::Secp256k1(e))?;
+
+ let prng_seed = self.keys_manager.get_secure_random_bytes();
+ let onion_routing_packet = construct_onion_message_packet(
+ packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
+
+ let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
+ if outbound_buffer_full(&introduction_node_id, &pending_per_peer_msgs) { return Err(SendError::BufferFull) }
+ match pending_per_peer_msgs.entry(introduction_node_id) {
+ hash_map::Entry::Vacant(_) => Err(SendError::InvalidFirstHop),
+ hash_map::Entry::Occupied(mut e) => {
+ e.get_mut().push_back(msgs::OnionMessage { blinding_point, onion_routing_packet });
+ Ok(())
+ }
+ }
+ }
+
+ #[cfg(test)]
+ pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<msgs::OnionMessage>> {
+ let mut pending_msgs = self.pending_messages.lock().unwrap();
+ let mut msgs = HashMap::new();
+ // We don't want to disconnect the peers by removing them entirely from the original map, so we
+ // swap the pending message buffers individually.
+ for (peer_node_id, pending_messages) in &mut *pending_msgs {
+ msgs.insert(*peer_node_id, core::mem::take(pending_messages));
+ }
+ msgs
+ }
+}
+
+fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, VecDeque<msgs::OnionMessage>>) -> bool {
+ const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
+ const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
+ let mut total_buffered_bytes = 0;
+ let mut peer_buffered_bytes = 0;
+ for (pk, peer_buf) in buffer {
+ for om in peer_buf {
+ let om_len = om.serialized_length();
+ if pk == peer_node_id {
+ peer_buffered_bytes += om_len;
+ }
+ total_buffered_bytes += om_len;
+
+ if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
+ peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
+ {
+ return true
+ }
+ }
+ }
+ false
+}
+
+impl<K: Deref, L: Deref, CMH: Deref> OnionMessageHandler for OnionMessenger<K, L, CMH>
+ where K::Target: KeysInterface,
+ L::Target: Logger,
+ CMH::Target: CustomOnionMessageHandler + Sized,
+{
+ /// Handle an incoming onion message. Currently, if a message was destined for us we will log, but
+ /// soon we'll delegate the onion message to a handler that can generate invoices or send
+ /// payments.
+ fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &msgs::OnionMessage) {
+ let control_tlvs_ss = match self.keys_manager.ecdh(Recipient::Node, &msg.blinding_point, None) {
+ Ok(ss) => ss,
+ Err(e) => {
+ log_error!(self.logger, "Failed to retrieve node secret: {:?}", e);
+ return
+ }
+ };
+ let onion_decode_ss = {
+ let blinding_factor = {
+ let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
+ hmac.input(control_tlvs_ss.as_ref());
+ Hmac::from_engine(hmac).into_inner()
+ };
+ match self.keys_manager.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
+ Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
+ {
+ Ok(ss) => ss.secret_bytes(),
+ Err(()) => {
+ log_trace!(self.logger, "Failed to compute onion packet shared secret");
+ return
+ }
+ }
+ };
+ match onion_utils::decode_next_untagged_hop(onion_decode_ss, &msg.onion_routing_packet.hop_data[..],
+ msg.onion_routing_packet.hmac, (control_tlvs_ss, &*self.custom_handler))
+ {
+ Ok((Payload::Receive::<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage> {
+ message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
+ }, None)) => {
+ log_info!(self.logger,
+ "Received an onion message with path_id {:02x?} and {} reply_path",
+ path_id, if reply_path.is_some() { "a" } else { "no" });
+ match message {
+ OnionMessageContents::Custom(msg) => self.custom_handler.handle_custom_message(msg),
+ }
+ },
+ Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
+ next_node_id, next_blinding_override
+ })), Some((next_hop_hmac, new_packet_bytes)))) => {
+ // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
+ // blinded hop and this onion message is destined for us. In this situation, we should keep
+ // unwrapping the onion layers to get to the final payload. Since we don't have the option
+ // of creating blinded paths with dummy hops currently, we should be ok to not handle this
+ // for now.
+ let new_pubkey = match onion_utils::next_hop_packet_pubkey(&self.secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
+ Ok(pk) => pk,
+ Err(e) => {
+ log_trace!(self.logger, "Failed to compute next hop packet pubkey: {}", e);
+ return
+ }
+ };
+ let outgoing_packet = Packet {
+ version: 0,
+ public_key: new_pubkey,
+ hop_data: new_packet_bytes,
+ hmac: next_hop_hmac,
+ };
+ let onion_message = msgs::OnionMessage {
+ blinding_point: match next_blinding_override {
+ Some(blinding_point) => blinding_point,
+ None => {
+ let blinding_factor = {
+ let mut sha = Sha256::engine();
+ sha.input(&msg.blinding_point.serialize()[..]);
+ sha.input(control_tlvs_ss.as_ref());
+ Sha256::from_engine(sha).into_inner()
+ };
+ let next_blinding_point = msg.blinding_point;
+ match next_blinding_point.mul_tweak(&self.secp_ctx, &Scalar::from_be_bytes(blinding_factor).unwrap()) {
+ Ok(bp) => bp,
+ Err(e) => {
+ log_trace!(self.logger, "Failed to compute next blinding point: {}", e);
+ return
+ }
+ }
+ },
+ },
+ onion_routing_packet: outgoing_packet,
+ };
+
+ let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
+ if outbound_buffer_full(&next_node_id, &pending_per_peer_msgs) {
+ log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
+ return
+ }
+
+ #[cfg(fuzzing)]
+ pending_per_peer_msgs.entry(next_node_id).or_insert_with(VecDeque::new);
+
+ match pending_per_peer_msgs.entry(next_node_id) {
+ hash_map::Entry::Vacant(_) => {
+ log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
+ return
+ },
+ hash_map::Entry::Occupied(mut e) => {
+ e.get_mut().push_back(onion_message);
+ log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
+ }
+ };
+ },
+ Err(e) => {
+ log_trace!(self.logger, "Errored decoding onion message packet: {:?}", e);
+ },
+ _ => {
+ log_trace!(self.logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
+ },
+ };
+ }
+
+ fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init) -> Result<(), ()> {
+ if init.features.supports_onion_messages() {
+ let mut peers = self.pending_messages.lock().unwrap();
+ peers.insert(their_node_id.clone(), VecDeque::new());
+ }
+ Ok(())
+ }
+
+ fn peer_disconnected(&self, their_node_id: &PublicKey, _no_connection_possible: bool) {
+ let mut pending_msgs = self.pending_messages.lock().unwrap();
+ pending_msgs.remove(their_node_id);
+ }
+
+ fn provided_node_features(&self) -> NodeFeatures {
+ let mut features = NodeFeatures::empty();
+ features.set_onion_messages_optional();
+ features
+ }
+
+ fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
+ let mut features = InitFeatures::empty();
+ features.set_onion_messages_optional();
+ features
+ }
+}
+
+impl<K: Deref, L: Deref, CMH: Deref> OnionMessageProvider for OnionMessenger<K, L, CMH>
+ where K::Target: KeysInterface,
+ L::Target: Logger,
+ CMH::Target: CustomOnionMessageHandler,
+{
+ fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage> {
+ let mut pending_msgs = self.pending_messages.lock().unwrap();
+ if let Some(msgs) = pending_msgs.get_mut(&peer_node_id) {
+ return msgs.pop_front()
+ }
+ None
+ }
}
// TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
/// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
/// [`SimpleArcPeerManager`]. See their docs for more details.
///
-///[`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
-///[`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
-pub type SimpleArcOnionMessenger<L> = OnionMessenger<InMemorySigner, Arc<KeysManager>, Arc<L>>;
+/// (C-not exported) as `Arc`s don't make sense in bindings.
+///
+/// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
+/// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
+pub type SimpleArcOnionMessenger<L> = OnionMessenger<Arc<KeysManager>, Arc<L>, IgnoringMessageHandler>;
/// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
/// [`SimpleRefPeerManager`]. See their docs for more details.
///
-///[`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
-///[`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
-pub type SimpleRefOnionMessenger<'a, 'b, L> = OnionMessenger<InMemorySigner, &'a KeysManager, &'b L>;
+/// (C-not exported) as general type aliases don't make sense in bindings.
+///
+/// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
+/// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
+pub type SimpleRefOnionMessenger<'a, 'b, L> = OnionMessenger<&'a KeysManager, &'b L, IgnoringMessageHandler>;
+
+/// Construct onion packet payloads and keys for sending an onion message along the given
+/// `unblinded_path` to the given `destination`.
+fn packet_payloads_and_keys<T: CustomOnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
+ secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination,
+ message: OnionMessageContents<T>, mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
+) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
+ let num_hops = unblinded_path.len() + destination.num_hops();
+ let mut payloads = Vec::with_capacity(num_hops);
+ let mut onion_packet_keys = Vec::with_capacity(num_hops);
+
+ let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
+ introduction_node_id, blinding_point, blinded_hops }) = &destination {
+ (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
+ let num_unblinded_hops = num_hops - num_blinded_hops;
+
+ let mut unblinded_path_idx = 0;
+ let mut blinded_path_idx = 0;
+ let mut prev_control_tlvs_ss = None;
+ let mut final_control_tlvs = None;
+ utils::construct_keys_callback(secp_ctx, unblinded_path, Some(destination), session_priv, |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
+ if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
+ if let Some(ss) = prev_control_tlvs_ss.take() {
+ payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
+ ForwardTlvs {
+ next_node_id: unblinded_pk_opt.unwrap(),
+ next_blinding_override: None,
+ }
+ )), ss));
+ }
+ prev_control_tlvs_ss = Some(control_tlvs_ss);
+ unblinded_path_idx += 1;
+ } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
+ if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
+ payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
+ next_node_id: intro_node_id,
+ next_blinding_override: Some(blinding_pt),
+ })), control_tlvs_ss));
+ }
+ }
+ if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
+ payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
+ control_tlvs_ss));
+ blinded_path_idx += 1;
+ } else if let Some(encrypted_payload) = enc_payload_opt {
+ final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
+ prev_control_tlvs_ss = Some(control_tlvs_ss);
+ }
+
+ let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
+ onion_packet_keys.push(onion_utils::OnionKeys {
+ #[cfg(test)]
+ shared_secret: onion_packet_ss,
+ #[cfg(test)]
+ blinding_factor: [0; 32],
+ ephemeral_pubkey,
+ rho,
+ mu,
+ });
+ })?;
+
+ if let Some(control_tlvs) = final_control_tlvs {
+ payloads.push((Payload::Receive {
+ control_tlvs,
+ reply_path: reply_path.take(),
+ message,
+ }, prev_control_tlvs_ss.unwrap()));
+ } else {
+ payloads.push((Payload::Receive {
+ control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
+ reply_path: reply_path.take(),
+ message,
+ }, prev_control_tlvs_ss.unwrap()));
+ }
+
+ Ok((payloads, onion_packet_keys))
+}
+
+/// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
+fn construct_onion_message_packet<T: CustomOnionMessageContents>(payloads: Vec<(Payload<T>, [u8; 32])>, onion_keys: Vec<onion_utils::OnionKeys>, prng_seed: [u8; 32]) -> Result<Packet, ()> {
+ // Spec rationale:
+ // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
+ // onion, but this should be used sparingly as it is reduces anonymity set, hence the
+ // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
+ let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
+ let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
+ SMALL_PACKET_HOP_DATA_LEN
+ } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
+ BIG_PACKET_HOP_DATA_LEN
+ } else { return Err(()) };
+
+ Ok(onion_utils::construct_onion_message_packet::<_, _>(
+ payloads, onion_keys, prng_seed, hop_data_len))
+}
projects / rust-lightning / blobdiff