X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fonion_message%2Fpacket.rs;h=d19bd30edd212be4b19286d5ef5f0bf0f1870a8f;hb=89749eddec2ea178858bb5bc96c7d79e02944586;hp=8b677e7bb611ea307067493bc2252685e7632636;hpb=1b356619b3b178ef5a4f392056ed2fd5b7de2541;p=rust-lightning

diff --git a/lightning/src/onion_message/packet.rs b/lightning/src/onion_message/packet.rs
index 8b677e7b..d19bd30e 100644
--- a/lightning/src/onion_message/packet.rs
+++ b/lightning/src/onion_message/packet.rs
@@ -32,16 +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 {
@@ -264,8 +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),
@@ -274,19 +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();
@@ -307,3 +311,12 @@ impl Readable for ControlTlvs {
 		Ok(payload_fmt)
 	}
 }
+
+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),
+		}
+	}
+}