X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fonion_message%2Fmessenger.rs;h=a3320f10d21091a0faa3131f3125384cc51b871f;hb=04f467342851691d368df1eb318bcfaf6c58a607;hp=f4cb57f28df3410949a67b8ffb3f7f7e48cc6ae1;hpb=9051c38ebe42e171fd0fcfa22d2b9ff6a1607b3b;p=rust-lightning diff --git a/lightning/src/onion_message/messenger.rs b/lightning/src/onion_message/messenger.rs index f4cb57f2..a3320f10 100644 --- a/lightning/src/onion_message/messenger.rs +++ b/lightning/src/onion_message/messenger.rs @@ -10,14 +10,18 @@ //! 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; @@ -25,16 +29,63 @@ use sync::{Arc, Mutex}; 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::(&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]: +/// [`OnionMessenger`]: crate::onion_message::OnionMessenger pub struct OnionMessenger where K::Target: KeysInterface, L::Target: Logger, { keys_manager: K, logger: L, - pending_messages: Mutex>>, + pending_messages: Mutex>>, secp_ctx: Secp256k1, // Coming soon: // invoice_handler: InvoiceHandler, @@ -58,6 +109,23 @@ impl Destination { } } +/// 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 OnionMessenger where K::Target: KeysInterface, L::Target: Logger, @@ -76,7 +144,13 @@ impl OnionMessenger } /// 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) -> 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 { @@ -89,20 +163,169 @@ impl OnionMessenger } }; 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> { + 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 OnionMessageHandler for OnionMessenger + where K::Target: KeysInterface, + 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::::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 OnionMessageProvider for OnionMessenger + where K::Target: KeysInterface, + L::Target: Logger, +{ + fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option { + 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 } } @@ -124,7 +347,8 @@ pub type SimpleRefOnionMessenger<'a, 'b, L> = OnionMessenger( - secp_ctx: &Secp256k1, unblinded_path: &[PublicKey], destination: Destination, session_priv: &SecretKey + secp_ctx: &Secp256k1, unblinded_path: &[PublicKey], destination: Destination, mut reply_path: + Option, session_priv: &SecretKey ) -> Result<(Vec<(Payload, [u8; 32])>, Vec), secp256k1::Error> { let num_hops = unblinded_path.len() + destination.num_hops(); let mut payloads = Vec::with_capacity(num_hops); @@ -169,6 +393,7 @@ fn packet_payloads_and_keys( } 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)); } @@ -186,14 +411,16 @@ fn packet_payloads_and_keys( 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, 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, prng_seed: [u8; 32]) -> Result { // 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 @@ -203,7 +430,8 @@ fn construct_onion_message_packet(payloads: Vec<(Payload, [u8; 32])>, onion_keys 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)) }