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vpncloud/src/udpmessage.rs

336 lines
11 KiB
Rust
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use std::{mem, ptr, fmt, slice};
use std::net::{SocketAddr, SocketAddrV4, Ipv4Addr};
use std::u16;
use super::types::{Error, NetworkId, Range, Address};
use super::util::{as_obj, as_bytes, to_vec};
use super::Crypto;
const MAGIC: [u8; 3] = [0x76, 0x70, 0x6e];
const VERSION: u8 = 1;
#[repr(packed)]
struct TopHeader {
magic: [u8; 3],
version: u8,
_reserved: [u8; 2],
flags: u8,
msgtype: u8
}
impl Default for TopHeader {
fn default() -> Self {
TopHeader{magic: MAGIC, version: VERSION, _reserved: [0; 2], flags: 0, msgtype: 0}
}
}
#[derive(Default, Debug, PartialEq, Eq)]
pub struct Options {
pub network_id: Option<NetworkId>,
}
#[derive(PartialEq)]
pub enum Message<'a> {
Data(&'a[u8]),
Peers(Vec<SocketAddr>),
Init(Vec<Range>),
Close,
}
impl<'a> fmt::Debug for Message<'a> {
fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
match self {
&Message::Data(ref data) => write!(formatter, "Data(data: {} bytes)", data.len()),
&Message::Peers(ref peers) => {
try!(write!(formatter, "Peers ["));
let mut first = true;
for p in peers {
if !first {
try!(write!(formatter, ", "));
}
first = false;
try!(p.fmt(formatter));
}
write!(formatter, "]")
},
&Message::Init(ref data) => write!(formatter, "Init{:?}", data),
&Message::Close => write!(formatter, "Close"),
}
}
}
pub fn decode<'a>(data: &'a mut [u8], crypto: &mut Crypto) -> Result<(Options, Message<'a>), Error> {
if data.len() < mem::size_of::<TopHeader>() {
return Err(Error::ParseError("Empty message"));
}
let mut pos = 0;
let header = unsafe { as_obj::<TopHeader>(&data[pos..]) };
pos += mem::size_of::<TopHeader>();
if header.magic != MAGIC {
return Err(Error::ParseError("Wrong protocol"));
}
if header.version != VERSION {
return Err(Error::ParseError("Wrong version"));
}
let mut options = Options::default();
if header.flags & 0x01 > 0 {
if data.len() < pos + 8 {
return Err(Error::ParseError("Truncated options"));
}
let id = u64::from_be(*unsafe { as_obj::<u64>(&data[pos..]) });
options.network_id = Some(id);
pos += 8;
}
if header.flags & 0x02 > 0 {
if data.len() < pos + 40 {
return Err(Error::ParseError("Truncated options"));
}
if !crypto.is_secure() {
return Err(Error::CryptoError("Unexpected encrypted data"));
}
let nonce = &data[pos..pos+8];
pos += 8;
let hash = &data[pos..pos+32];
pos += 32;
// Cheat data mutable to make the borrow checker happy
let data = unsafe { slice::from_raw_parts_mut(mem::transmute(data[pos..].as_ptr()), data.len()-pos) };
try!(crypto.decrypt(data, nonce, hash));
}
let msg = match header.msgtype {
0 => Message::Data(&data[pos..]),
1 => {
if data.len() < pos + 1 {
return Err(Error::ParseError("Empty peers"));
}
let count = data[pos];
pos += 1;
let len = count as usize * 6;
if data.len() < pos + len {
return Err(Error::ParseError("Peer data too short"));
}
let mut peers = Vec::with_capacity(count as usize);
for _ in 0..count {
let (ip, port) = unsafe {
let ip = as_obj::<[u8; 4]>(&data[pos..]);
pos += 4;
let port = *as_obj::<u16>(&data[pos..]);
let port = u16::from_be(port);
pos += 2;
(ip, port)
};
let addr = SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(ip[0], ip[1], ip[2], ip[3]), port));
peers.push(addr);
}
Message::Peers(peers)
},
2 => {
if data.len() < pos + 1 {
return Err(Error::ParseError("Init data too short"));
}
let count = data[pos] as usize;
pos += 1;
let mut addrs = Vec::with_capacity(count);
for _ in 0..count {
if data.len() < pos + 1 {
return Err(Error::ParseError("Init data too short"));
}
let len = data[pos] as usize;
pos += 1;
if data.len() < pos + len {
return Err(Error::ParseError("Init data too short"));
}
let base = Address(to_vec(&data[pos..pos+len]));
pos += len;
if data.len() < pos + 1 {
return Err(Error::ParseError("Init data too short"));
}
let prefix_len = data[pos];
pos += 1;
addrs.push(Range{base: base, prefix_len: prefix_len});
}
Message::Init(addrs)
},
3 => Message::Close,
_ => return Err(Error::ParseError("Unknown message type"))
};
Ok((options, msg))
}
pub fn encode(options: &Options, msg: &Message, buf: &mut [u8], crypto: &mut Crypto) -> usize {
assert!(buf.len() >= mem::size_of::<TopHeader>());
let mut pos = 0;
let mut header = TopHeader::default();
header.msgtype = match msg {
&Message::Data(_) => 0,
&Message::Peers(_) => 1,
&Message::Init(_) => 2,
&Message::Close => 3
};
if options.network_id.is_some() {
header.flags |= 0x01;
}
if crypto.is_secure() {
header.flags |= 0x02
}
let header_dat = unsafe { as_bytes(&header) };
unsafe { ptr::copy_nonoverlapping(header_dat.as_ptr(), buf[pos..].as_mut_ptr(), header_dat.len()) };
pos += header_dat.len();
if let Some(id) = options.network_id {
assert!(buf.len() >= pos + 8);
unsafe {
let id_dat = mem::transmute::<u64, [u8; 8]>(id.to_be());
ptr::copy_nonoverlapping(id_dat.as_ptr(), buf[pos..].as_mut_ptr(), id_dat.len());
}
pos += 8;
}
let (nonce_pos, hash_pos) = if crypto.is_secure() {
let nonce_pos = pos;
pos += 8;
let hash_pos = pos;
pos += 32;
(nonce_pos, hash_pos)
} else {
(0, 0)
};
let crypto_pos = pos;
match msg {
&Message::Data(ref data) => {
assert!(buf.len() >= pos + data.len());
unsafe { ptr::copy_nonoverlapping(data.as_ptr(), buf[pos..].as_mut_ptr(), data.len()) };
pos += data.len();
},
&Message::Peers(ref peers) => {
let count_pos = pos;
pos += 1;
assert!(buf.len() >= 2 + peers.len() * mem::size_of::<SocketAddrV4>());
let mut count = 0;
for p in peers {
match p {
&SocketAddr::V4(addr) => {
let ip = addr.ip().octets();
let port = addr.port();
unsafe {
ptr::copy_nonoverlapping(ip.as_ptr(), buf[pos..].as_mut_ptr(), ip.len());
pos += ip.len();
let port = mem::transmute::<u16, [u8; 2]>(port.to_be());
ptr::copy_nonoverlapping(port.as_ptr(), buf[pos..].as_mut_ptr(), port.len());
pos += port.len();
}
count += 1;
},
&SocketAddr::V6(_addr) => unimplemented!()
}
};
buf[count_pos] = count;
buf[pos] = 0;
pos += 1;
},
&Message::Init(ref ranges) => {
assert!(buf.len() >= pos + 1);
assert!(ranges.len() <= 255);
buf[pos] = ranges.len() as u8;
pos += 1;
for range in ranges {
let base = &range.base;
let len = base.0.len();
assert!(len <= 255);
assert!(buf.len() >= pos + 1 + len + 1);
buf[pos] = len as u8;
pos += 1;
unsafe { ptr::copy_nonoverlapping(base.0.as_ptr(), buf[pos..].as_mut_ptr(), len) };
pos += len;
buf[pos] = range.prefix_len;
pos += 1;
}
},
&Message::Close => {
}
}
if crypto.is_secure() {
let (nonce, hash) = crypto.encrypt(&mut buf[crypto_pos..pos]);
assert_eq!(nonce.len(), 8);
assert_eq!(hash.len(), 32);
unsafe {
ptr::copy_nonoverlapping(nonce.as_ptr(), buf[nonce_pos..].as_mut_ptr(), 8);
ptr::copy_nonoverlapping(hash.as_ptr(), buf[hash_pos..].as_mut_ptr(), 32);
}
}
pos
}
#[test]
fn encode_message_packet() {
let mut options = Options::default();
let mut crypto = Crypto::None;
let payload = [1,2,3,4,5];
let msg = Message::Data(&payload);
let mut buf = [0; 1024];
let size = encode(&mut options, &msg, &mut buf[..], &mut crypto);
assert_eq!(size, 13);
assert_eq!(&buf[..8], &[118,112,110,0,0,0,0,0]);
let (options2, msg2) = decode(&mut buf[..size], &mut crypto).unwrap();
assert_eq!(options, options2);
assert_eq!(msg, msg2);
}
#[test]
fn encode_message_peers() {
use std::str::FromStr;
let mut options = Options::default();
let mut crypto = Crypto::None;
let msg = Message::Peers(vec![SocketAddr::from_str("1.2.3.4:123").unwrap(), SocketAddr::from_str("5.6.7.8:12345").unwrap()]);
let mut buf = [0; 1024];
let size = encode(&mut options, &msg, &mut buf[..], &mut crypto);
assert_eq!(size, 22);
assert_eq!(&buf[..size], &[118,112,110,0,0,0,0,1,2,1,2,3,4,0,123,5,6,7,8,48,57,0]);
let (options2, msg2) = decode(&mut buf[..size], &mut crypto).unwrap();
assert_eq!(options, options2);
assert_eq!(msg, msg2);
}
#[test]
fn encode_option_network_id() {
let mut options = Options::default();
options.network_id = Some(134);
let mut crypto = Crypto::None;
let msg = Message::Close;
let mut buf = [0; 1024];
let size = encode(&mut options, &msg, &mut buf[..], &mut crypto);
assert_eq!(size, 16);
assert_eq!(&buf[..size], &[118,112,110,0,0,0,1,3,0,0,0,0,0,0,0,134]);
let (options2, msg2) = decode(&mut buf[..size], &mut crypto).unwrap();
assert_eq!(options, options2);
assert_eq!(msg, msg2);
}
#[test]
fn encode_message_init() {
let mut options = Options::default();
let mut crypto = Crypto::None;
let addrs = vec![];
let msg = Message::Init(addrs);
let mut buf = [0; 1024];
let size = encode(&mut options, &msg, &mut buf[..], &mut crypto);
assert_eq!(size, 9);
assert_eq!(&buf[..size], &[118,112,110,0,0,0,0,2,0]);
let (options2, msg2) = decode(&mut buf[..size], &mut crypto).unwrap();
assert_eq!(options, options2);
assert_eq!(msg, msg2);
}
#[test]
fn encode_message_close() {
let mut options = Options::default();
let mut crypto = Crypto::None;
let msg = Message::Close;
let mut buf = [0; 1024];
let size = encode(&mut options, &msg, &mut buf[..], &mut crypto);
assert_eq!(size, 8);
assert_eq!(&buf[..size], &[118,112,110,0,0,0,0,3]);
let (options2, msg2) = decode(&mut buf[..size], &mut crypto).unwrap();
assert_eq!(options, options2);
assert_eq!(msg, msg2);
}
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