use bitcoin::hashes::{Hash, HashEngine};
use bitcoin::hashes::hmac::{Hmac, HmacEngine};
use bitcoin::hashes::sha256::Hash as Sha256;
-use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey};
+use bitcoin::secp256k1::{self, PublicKey, Scalar, Secp256k1, SecretKey};
use chain::keysinterface::{InMemorySigner, KeysInterface, KeysManager, Recipient, Sign};
use ln::msgs;
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
+///
+// Needs to be `ignore` until the `onion_message` module is made public, otherwise this is a test
+// failure.
+/// ```ignore
+/// # 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];
+/// onion_messenger.send_onion_message(&intermediate_hops, Destination::Node(destination_node_id));
+///
+/// // 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];
+/// onion_messenger.send_onion_message(&intermediate_hops, Destination::BlindedRoute(blinded_route));
+/// ```
///
/// [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,
}
}
+/// 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,
+}
+
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) -> 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, &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_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());
Hmac::from_engine(hmac).into_inner()
};
match self.keys_manager.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
- Some(&blinding_factor))
+ Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
{
Ok(ss) => ss.secret_bytes(),
Err(()) => {
Sha256::from_engine(sha).into_inner()
};
let mut next_blinding_point = msg.blinding_point;
- if let Err(e) = next_blinding_point.mul_assign(&self.secp_ctx, &blinding_factor[..]) {
- log_trace!(self.logger, "Failed to compute next blinding point: {}", e);
- return
+ 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
+ }
}
- next_blinding_point
},
},
onion_routing_packet: outgoing_packet,
},
};
}
+
+ #[cfg(test)]
+ pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, Vec<msgs::OnionMessage>> {
+ let mut pending_msgs = self.pending_messages.lock().unwrap();
+ let mut msgs = HashMap::new();
+ core::mem::swap(&mut *pending_msgs, &mut msgs);
+ msgs
+ }
}
// TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
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))
}