mirror of https://github.com/dswd/vpncloud.git
262 lines
9.0 KiB
Rust
262 lines
9.0 KiB
Rust
// VpnCloud - Peer-to-Peer VPN
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// Copyright (C) 2015-2017 Dennis Schwerdel
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// This software is licensed under GPL-3 or newer (see LICENSE.md)
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use std::fmt;
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use std::net::{SocketAddr, SocketAddrV4, Ipv4Addr, SocketAddrV6, Ipv6Addr};
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use super::types::{NodeId, HeaderMagic, Error, Range, NODE_ID_BYTES};
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use super::util::{bytes_to_hex, Encoder};
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use super::crypto::Crypto;
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#[derive(Clone, Copy, Default)]
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#[repr(packed)]
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struct TopHeader {
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magic: HeaderMagic,
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crypto_method : u8,
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_reserved1: u8,
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_reserved2: u8,
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msgtype: u8
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}
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impl TopHeader {
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#[inline]
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pub fn size() -> usize {
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8
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}
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pub fn read_from(data: &[u8]) -> Result<(TopHeader, usize), Error> {
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if data.len() < TopHeader::size() {
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return Err(Error::Parse("Empty message"));
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}
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let mut header = TopHeader::default();
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header.magic.copy_from_slice(&data[0..4]);
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header.crypto_method = data[4];
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header.msgtype = data[7];
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Ok((header, TopHeader::size()))
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}
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pub fn write_to(&self, data: &mut [u8]) -> usize {
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assert!(data.len() >= 8);
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data[0..4].copy_from_slice(&self.magic);
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data[4] = self.crypto_method;
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data[5] = 0;
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data[6] = 0;
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data[7] = self.msgtype;
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TopHeader::size()
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}
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}
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pub enum Message<'a> {
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Data(&'a mut[u8], usize, usize), // data, start, end
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Peers(Vec<SocketAddr>), // peers
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Init(u8, NodeId, Vec<Range>), // step, node_id, ranges
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Close,
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}
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impl<'a> fmt::Debug for Message<'a> {
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fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
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match *self {
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Message::Data(_, start, end) => write!(formatter, "Data({} bytes)", end-start),
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Message::Peers(ref peers) => {
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try!(write!(formatter, "Peers ["));
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let mut first = true;
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for p in peers {
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if !first {
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try!(write!(formatter, ", "));
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}
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first = false;
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try!(write!(formatter, "{}", p));
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}
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write!(formatter, "]")
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},
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Message::Init(stage, ref node_id, ref peers) => write!(formatter, "Init(stage={}, node_id={}, {:?})", stage, bytes_to_hex(node_id), peers),
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Message::Close => write!(formatter, "Close"),
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}
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}
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}
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#[allow(unknown_lints)]
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#[allow(needless_range_loop)]
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pub fn decode<'a>(data: &'a mut [u8], magic: HeaderMagic, crypto: &mut Crypto) -> Result<Message<'a>, Error> {
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let mut end = data.len();
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let (header, mut pos) = try!(TopHeader::read_from(&data[..end]));
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if header.magic != magic {
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return Err(Error::WrongHeaderMagic(header.magic));
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}
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if header.crypto_method != crypto.method() {
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return Err(Error::Crypto("Wrong crypto method"));
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}
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if crypto.method() > 0 {
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let len = crypto.nonce_bytes();
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if end < pos + len {
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return Err(Error::Parse("Truncated crypto header"));
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}
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{
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let (before, after) = data.split_at_mut(pos);
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let (nonce, crypto_data) = after.split_at_mut(len);
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pos += len;
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end = try!(crypto.decrypt(crypto_data, nonce, &before[..TopHeader::size()])) + pos;
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}
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assert_eq!(end, data.len()-crypto.additional_bytes());
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}
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let msg = match header.msgtype {
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0 => Message::Data(data, pos, end),
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1 => {
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if end < pos + 1 {
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return Err(Error::Parse("Missing IPv4 count"));
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}
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let mut peers = Vec::new();
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let count = data[pos];
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pos += 1;
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let len = count as usize * 6;
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if end < pos + len {
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return Err(Error::Parse("IPv4 peer data too short"));
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}
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for _ in 0..count {
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let ip = &data[pos..];
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assert!(ip.len() >= 4);
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pos += 4;
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let port = Encoder::read_u16(&data[pos..]);
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pos += 2;
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let addr = SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(ip[0], ip[1], ip[2], ip[3]), port));
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peers.push(addr);
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}
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if end < pos + 1 {
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return Err(Error::Parse("Missing IPv6 count"));
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}
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let count = data[pos];
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pos += 1;
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let len = count as usize * 18;
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if end < pos + len {
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return Err(Error::Parse("IPv6 peer data too short"));
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}
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for _ in 0..count {
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let mut ip = [0u16; 8];
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for i in 0..8 {
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ip[i] = Encoder::read_u16(&data[pos..]);
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pos += 2;
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}
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let port = Encoder::read_u16(&data[pos..]);
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pos += 2;
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let addr = SocketAddr::V6(SocketAddrV6::new(Ipv6Addr::new(ip[0], ip[1], ip[2],
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ip[3], ip[4], ip[5], ip[6], ip[7]), port, 0, 0));
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peers.push(addr);
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}
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Message::Peers(peers)
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},
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2 => {
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if end < pos + 2 + NODE_ID_BYTES {
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return Err(Error::Parse("Init data too short"));
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}
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let stage = data[pos];
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pos += 1;
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let mut node_id = [0; NODE_ID_BYTES];
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node_id.copy_from_slice(&data[pos..pos+NODE_ID_BYTES]);
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pos += NODE_ID_BYTES;
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let count = data[pos] as usize;
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pos += 1;
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let mut addrs = Vec::with_capacity(count);
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for _ in 0..count {
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let (range, read) = try!(Range::read_from(&data[pos..end]));
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pos += read;
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addrs.push(range);
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}
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Message::Init(stage, node_id, addrs)
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},
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3 => Message::Close,
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_ => return Err(Error::Parse("Unknown message type"))
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};
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Ok(msg)
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}
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#[allow(unknown_lints)]
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#[allow(needless_range_loop)]
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pub fn encode<'a>(msg: &'a mut Message, mut buf: &'a mut [u8], magic: HeaderMagic, crypto: &mut Crypto) -> &'a mut [u8] {
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let mut start = 64;
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let mut end = 64;
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match *msg {
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Message::Data(ref mut data, data_start, data_end) => {
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buf = data;
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start = data_start;
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end = data_end;
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},
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Message::Peers(ref peers) => {
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let mut v4addrs = Vec::new();
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let mut v6addrs = Vec::new();
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for p in peers {
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match *p {
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SocketAddr::V4(addr) => v4addrs.push(addr),
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SocketAddr::V6(addr) => v6addrs.push(addr)
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}
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};
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assert!(v4addrs.len() <= 255);
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assert!(v6addrs.len() <= 255);
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let mut pos = start;
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assert!(buf.len() >= pos + 2 + v4addrs.len() * 6 + v6addrs.len() * 18);
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buf[pos] = v4addrs.len() as u8;
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pos += 1;
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for addr in v4addrs {
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let ip = addr.ip().octets();
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buf[pos..pos+4].copy_from_slice(&ip);
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pos += 4;
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Encoder::write_u16(addr.port(), &mut buf[pos..]);
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pos += 2;
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};
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buf[pos] = v6addrs.len() as u8;
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pos += 1;
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for addr in v6addrs {
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let ip = addr.ip().segments();
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for i in 0..8 {
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Encoder::write_u16(ip[i], &mut buf[pos..]);
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pos += 2;
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}
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Encoder::write_u16(addr.port(), &mut buf[pos..]);
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pos += 2;
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};
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end = pos;
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},
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Message::Init(stage, ref node_id, ref ranges) => {
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let mut pos = start;
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assert!(buf.len() >= pos + 2 + NODE_ID_BYTES);
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buf[pos] = stage;
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pos += 1;
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buf[pos..pos+NODE_ID_BYTES].copy_from_slice(node_id);
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pos += NODE_ID_BYTES;
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assert!(ranges.len() <= 255);
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buf[pos] = ranges.len() as u8;
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pos += 1;
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for range in ranges {
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pos += range.write_to(&mut buf[pos..]);
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}
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end = pos;
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},
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Message::Close => {
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}
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}
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assert!(start >= 64);
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assert!(buf.len() >= end + 64);
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let crypto_start = start;
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start -= crypto.nonce_bytes();
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let mut header = TopHeader::default();
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header.magic = magic;
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header.msgtype = match *msg {
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Message::Data(_, _, _) => 0,
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Message::Peers(_) => 1,
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Message::Init(_, _, _) => 2,
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Message::Close => 3
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};
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header.crypto_method = crypto.method();
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start -= TopHeader::size();
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header.write_to(&mut buf[start..]);
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if crypto.method() > 0 {
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let (junk_before, rest) = buf.split_at_mut(start);
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let (header, rest) = rest.split_at_mut(TopHeader::size());
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let (nonce, rest) = rest.split_at_mut(crypto.nonce_bytes());
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debug_assert_eq!(junk_before.len() + header.len() + crypto.nonce_bytes(), crypto_start);
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assert!(rest.len() >= end - crypto_start + crypto.additional_bytes());
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end = crypto.encrypt(rest, end-crypto_start, nonce, header) + crypto_start;
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}
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&mut buf[start..end]
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}
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