Merge pull request #2583 from Evanfeenstra/pub-make-onion

[rust-lightning] / lightning / src / onion_message / packet.rs

diff --git a/lightning/src/onion_message/packet.rs b/lightning/src/onion_message/packet.rs
index 8a5628f164ca358dd8df1d7aec5e58730247c67e..d19bd30edd212be4b19286d5ef5f0bf0f1870a8f 100644 (file)
--- a/lightning/src/onion_message/packet.rs
+++ b/lightning/src/onion_message/packet.rs
@@ -12,7 +12,9 @@
 use bitcoin::secp256k1::PublicKey;
 use bitcoin::secp256k1::ecdh::SharedSecret;
 
-use crate::blinded_path::{BlindedPath, ForwardTlvs, ReceiveTlvs};
+use crate::blinded_path::BlindedPath;
+use crate::blinded_path::message::{ForwardTlvs, ReceiveTlvs};
+use crate::blinded_path::utils::Padding;
 use crate::ln::msgs::DecodeError;
 use crate::ln::onion_utils;
 use super::messenger::CustomOnionMessageHandler;
@@ -30,16 +32,22 @@ use crate::prelude::*;
 pub(super) const SMALL_PACKET_HOP_DATA_LEN: usize = 1300;
 pub(super) const BIG_PACKET_HOP_DATA_LEN: usize = 32768;
 
+/// Packet of hop data for next peer
 #[derive(Clone, Debug, PartialEq, Eq)]
-pub(crate) struct Packet {
-       pub(super) version: u8,
-       pub(super) public_key: PublicKey,
+pub struct Packet {
+       /// Bolt 04 version number
+       pub version: u8,
+       /// A random sepc256k1 point, used to build the ECDH shared secret to decrypt hop_data
+       pub public_key: PublicKey,
+       /// Encrypted payload for the next hop
+       //
        // Unlike the onion packets used for payments, onion message packets can have payloads greater
        // than 1300 bytes.
        // TODO: if 1300 ends up being the most common size, optimize this to be:
        // enum { ThirteenHundred([u8; 1300]), VarLen(Vec<u8>) }
-       pub(super) hop_data: Vec<u8>,
-       pub(super) hmac: [u8; 32],
+       pub hop_data: Vec<u8>,
+       /// HMAC to verify the integrity of hop_data
+       pub hmac: [u8; 32],
 }
 
 impl onion_utils::Packet for Packet {
@@ -151,7 +159,8 @@ pub(super) enum ForwardControlTlvs {
        Blinded(Vec<u8>),
        /// If we're constructing an onion message hop through an intermediate unblinded node, we'll need
        /// to construct the intermediate hop's control TLVs in their unblinded state to avoid encoding
-       /// them into an intermediate Vec. See [`crate::blinded_path::ForwardTlvs`] for more info.
+       /// them into an intermediate Vec. See [`crate::blinded_path::message::ForwardTlvs`] for more
+       /// info.
        Unblinded(ForwardTlvs),
 }
 
@@ -159,7 +168,7 @@ pub(super) enum ForwardControlTlvs {
 pub(super) enum ReceiveControlTlvs {
        /// See [`ForwardControlTlvs::Blinded`].
        Blinded(Vec<u8>),
-       /// See [`ForwardControlTlvs::Unblinded`] and [`crate::blinded_path::ReceiveTlvs`].
+       /// See [`ForwardControlTlvs::Unblinded`] and [`crate::blinded_path::message::ReceiveTlvs`].
        Unblinded(ReceiveTlvs),
 }
 
@@ -261,8 +270,9 @@ ReadableArgs<(SharedSecret, &H, &L)> for Payload<<H as CustomOnionMessageHandler
 }
 
 /// When reading a packet off the wire, we don't know a priori whether the packet is to be forwarded
-/// or received. Thus we read a ControlTlvs rather than reading a ForwardControlTlvs or
-/// ReceiveControlTlvs directly.
+/// or received. Thus we read a `ControlTlvs` rather than reading a [`ForwardTlvs`] or
+/// [`ReceiveTlvs`] directly. Also useful on the encoding side to keep forward and receive TLVs in
+/// the same iterator.
 pub(crate) enum ControlTlvs {
        /// This onion message is intended to be forwarded.
        Forward(ForwardTlvs),
@@ -271,19 +281,16 @@ pub(crate) enum ControlTlvs {
 }
 
 impl Readable for ControlTlvs {
-       fn read<R: Read>(mut r: &mut R) -> Result<Self, DecodeError> {
-               let mut _padding: Option<Padding> = None;
-               let mut _short_channel_id: Option<u64> = None;
-               let mut next_node_id: Option<PublicKey> = None;
-               let mut path_id: Option<[u8; 32]> = None;
-               let mut next_blinding_override: Option<PublicKey> = None;
-               decode_tlv_stream!(&mut r, {
+       fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+               _init_and_read_tlv_stream!(r, {
                        (1, _padding, option),
                        (2, _short_channel_id, option),
                        (4, next_node_id, option),
                        (6, path_id, option),
                        (8, next_blinding_override, option),
                });
+               let _padding: Option<Padding> = _padding;
+               let _short_channel_id: Option<u64> = _short_channel_id;
 
                let valid_fwd_fmt  = next_node_id.is_some() && path_id.is_none();
                let valid_recv_fmt = next_node_id.is_none() && next_blinding_override.is_none();
@@ -305,15 +312,11 @@ impl Readable for ControlTlvs {
        }
 }
 
-/// Reads padding to the end, ignoring what's read.
-pub(crate) struct Padding {}
-impl Readable for Padding {
-       #[inline]
-       fn read<R: Read>(reader: &mut R) -> Result<Self, DecodeError> {
-               loop {
-                       let mut buf = [0; 8192];
-                       if reader.read(&mut buf[..])? == 0 { break; }
+impl Writeable for ControlTlvs {
+       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+               match self {
+                       Self::Forward(tlvs) => tlvs.write(w),
+                       Self::Receive(tlvs) => tlvs.write(w),
                }
-               Ok(Self {})
        }
 }