//! LDK sends, receives, and forwards onion messages via the [`OnionMessenger`]. See its docs for
//! more information.
-use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey};
+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 chain::keysinterface::{InMemorySigner, KeysInterface, KeysManager, Recipient, Sign};
+use ln::msgs::{self, OnionMessageHandler};
use ln::onion_utils;
use super::blinded_route::{BlindedRoute, ForwardTlvs, ReceiveTlvs};
use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
use super::utils;
+use util::events::OnionMessageProvider;
use util::logger::Logger;
use core::ops::Deref;
use 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 empty 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::onion_message::{BlindedRoute, Destination, OnionMessenger};
+/// # use lightning::util::logger::{Logger, Record};
+/// # 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;
+/// #
+/// // 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);
+///
+/// // Send an empty onion message to a node id.
+/// let intermediate_hops = [hop_node_id1, hop_node_id2];
+/// let reply_path = None;
+/// onion_messenger.send_onion_message(&intermediate_hops, Destination::Node(destination_node_id), reply_path);
+///
+/// // Create a blinded route 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_route = BlindedRoute::new::<InMemorySigner, _, _>(&hops, &keys_manager, &secp_ctx).unwrap();
+///
+/// // Send an empty onion message to a blinded route.
+/// # let intermediate_hops = [hop_node_id1, hop_node_id2];
+/// let reply_path = None;
+/// onion_messenger.send_onion_message(&intermediate_hops, Destination::BlindedRoute(blinded_route), reply_path);
+/// ```
///
/// [offers]: <https://github.com/lightning/bolts/pull/798>
+/// [`OnionMessenger`]: crate::onion_message::OnionMessenger
pub struct OnionMessenger<Signer: Sign, K: Deref, L: Deref>
where K::Target: KeysInterface<Signer = Signer>,
L::Target: Logger,
{
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>,
// Coming soon:
// invoice_handler: InvoiceHandler,
}
}
+/// Errors that may occur when [sending an onion message].
+///
+/// [sending an onion message]: OnionMessenger::send_onion_message
+#[derive(Debug, PartialEq)]
+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 [`BlindedRoute`], due to having fewer than two
+ /// blinded hops.
+ TooFewBlindedHops,
+ /// Our next-hop peer was offline or does not support onion message forwarding.
+ InvalidFirstHop,
+}
+
impl<Signer: Sign, K: Deref, L: Deref> OnionMessenger<Signer, K, L>
where K::Target: KeysInterface<Signer = Signer>,
L::Target: Logger,
}
/// Send an empty onion message to `destination`, routing it through `intermediate_nodes`.
- pub fn send_onion_message(&self, intermediate_nodes: &[PublicKey], destination: Destination) -> Result<(), secp256k1::Error> {
+ /// See [`OnionMessenger`] for example usage.
+ pub fn send_onion_message(&self, intermediate_nodes: &[PublicKey], destination: Destination, reply_path: Option<BlindedRoute>) -> Result<(), SendError> {
+ if let Destination::BlindedRoute(BlindedRoute { ref blinded_hops, .. }) = destination {
+ if blinded_hops.len() < 2 {
+ return Err(SendError::TooFewBlindedHops);
+ }
+ }
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 {
}
};
let (packet_payloads, packet_keys) = packet_payloads_and_keys(
- &self.secp_ctx, intermediate_nodes, destination, &blinding_secret)?;
+ &self.secp_ctx, intermediate_nodes, destination, reply_path, &blinding_secret)
+ .map_err(|e| SendError::Secp256k1(e))?;
let prng_seed = self.keys_manager.get_secure_random_bytes();
- let onion_packet = construct_onion_message_packet(packet_payloads, packet_keys, prng_seed);
+ 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();
- let pending_msgs = pending_per_peer_msgs.entry(introduction_node_id).or_insert(Vec::new());
- pending_msgs.push(
- msgs::OnionMessage {
- blinding_point,
- onion_routing_packet: onion_packet,
+ 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
+ }
+}
+
+impl<Signer: Sign, K: Deref, L: Deref> OnionMessageHandler for OnionMessenger<Signer, K, L>
+ where K::Target: KeysInterface<Signer = Signer>,
+ L::Target: Logger,
+{
+ /// 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
}
- );
- Ok(())
+ };
+ 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_hop(onion_decode_ss, &msg.onion_routing_packet.hop_data[..],
+ msg.onion_routing_packet.hmac, control_tlvs_ss)
+ {
+ Ok((Payload::Receive {
+ 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() { "" } else { "no " });
+ },
+ 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 routes 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();
+
+ #[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) {
+ if init.features.supports_onion_messages() {
+ let mut peers = self.pending_messages.lock().unwrap();
+ peers.insert(their_node_id.clone(), VecDeque::new());
+ }
+ }
+
+ 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);
+ }
+}
+
+impl<Signer: Sign, K: Deref, L: Deref> OnionMessageProvider for OnionMessenger<Signer, K, L>
+ where K::Target: KeysInterface<Signer = Signer>,
+ L::Target: Logger,
+{
+ 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
}
}
/// 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: secp256k1::Signing + secp256k1::Verification>(
- secp_ctx: &Secp256k1<T>, unblinded_path: &[PublicKey], destination: Destination, session_priv: &SecretKey
+ secp_ctx: &Secp256k1<T>, unblinded_path: &[PublicKey], destination: Destination, mut reply_path:
+ Option<BlindedRoute>, session_priv: &SecretKey
) -> Result<(Vec<(Payload, [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);
} else if let Some(encrypted_payload) = enc_payload_opt {
payloads.push((Payload::Receive {
control_tlvs: ReceiveControlTlvs::Blinded(encrypted_payload),
+ reply_path: reply_path.take(),
}, control_tlvs_ss));
}
if let Some(control_tlvs_ss) = prev_control_tlvs_ss {
payloads.push((Payload::Receive {
- control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, })
+ control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
+ reply_path: reply_path.take(),
}, control_tlvs_ss));
}
Ok((payloads, onion_packet_keys))
}
-fn construct_onion_message_packet(payloads: Vec<(Payload, [u8; 32])>, onion_keys: Vec<onion_utils::OnionKeys>, prng_seed: [u8; 32]) -> Packet {
+/// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
+fn construct_onion_message_packet(payloads: Vec<(Payload, [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
SMALL_PACKET_HOP_DATA_LEN
} else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
BIG_PACKET_HOP_DATA_LEN
- } else { payloads_ser_len };
+ } else { return Err(()) };
- onion_utils::construct_onion_message_packet::<_, _>(payloads, onion_keys, prng_seed, hop_data_len)
+ Ok(onion_utils::construct_onion_message_packet::<_, _>(
+ payloads, onion_keys, prng_seed, hop_data_len))
}
projects / rust-lightning / blobdiff