X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fonion_message%2Fpacket.rs;fp=lightning%2Fsrc%2Fonion_message%2Fpacket.rs;h=37f178f5521ccfcc6f5f26738f949bc69945872b;hb=33ff2746ef3d1a36aab4f07cd1a7b512b6e411da;hp=0000000000000000000000000000000000000000;hpb=4e5381a50fa524cb183a3d92dee05cb4f2950255;p=rust-lightning

diff --git a/lightning/src/onion_message/packet.rs b/lightning/src/onion_message/packet.rs
new file mode 100644
index 00000000..37f178f5
--- /dev/null
+++ b/lightning/src/onion_message/packet.rs
@@ -0,0 +1,82 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+//! Structs and enums useful for constructing and reading an onion message packet.
+
+use bitcoin::secp256k1::PublicKey;
+
+use ln::msgs::DecodeError;
+use ln::onion_utils;
+use util::ser::{LengthRead, LengthReadable, Readable, Writeable, Writer};
+
+use core::cmp;
+use io;
+use prelude::*;
+
+#[derive(Clone, Debug, PartialEq)]
+pub(crate) struct Packet {
+	version: u8,
+	public_key: PublicKey,
+	// 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>) }
+	hop_data: Vec<u8>,
+	hmac: [u8; 32],
+}
+
+impl onion_utils::Packet for Packet {
+	type Data = Vec<u8>;
+	fn new(public_key: PublicKey, hop_data: Vec<u8>, hmac: [u8; 32]) -> Packet {
+		Self {
+			version: 0,
+			public_key,
+			hop_data,
+			hmac,
+		}
+	}
+}
+
+impl Writeable for Packet {
+	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+		self.version.write(w)?;
+		self.public_key.write(w)?;
+		w.write_all(&self.hop_data)?;
+		self.hmac.write(w)?;
+		Ok(())
+	}
+}
+
+impl LengthReadable for Packet {
+	fn read<R: LengthRead>(r: &mut R) -> Result<Self, DecodeError> {
+		const READ_BUFFER_SIZE: usize = 4096;
+
+		let version = Readable::read(r)?;
+		let public_key = Readable::read(r)?;
+
+		let mut hop_data = Vec::new();
+		let hop_data_len = r.total_bytes() as usize - 66; // 1 (version) + 33 (pubkey) + 32 (HMAC) = 66
+		let mut read_idx = 0;
+		while read_idx < hop_data_len {
+			let mut read_buffer = [0; READ_BUFFER_SIZE];
+			let read_amt = cmp::min(hop_data_len - read_idx, READ_BUFFER_SIZE);
+			r.read_exact(&mut read_buffer[..read_amt]);
+			hop_data.extend_from_slice(&read_buffer[..read_amt]);
+			read_idx += read_amt;
+		}
+
+		let hmac = Readable::read(r)?;
+		Ok(Packet {
+			version,
+			public_key,
+			hop_data,
+			hmac,
+		})
+	}
+}