Configurable magic header instead of network id (re #5)

CHANGELOG.md

@@ -4,6 +4,9 @@ This project follows [semantic versioning](http://semver.org).
 
 ### UNRELEASED
 
+- [changed] Configurable magic header is now used instead of Network-ID (**incompatible**)
+- [fixed] Fixed documentation of listen parameter
+- [fixed] Fixed problem with multiple subnets
 
 ### v0.7.0 (2016-08-05)
 

src/benches.rs

@@ -8,9 +8,10 @@ use std::str::FromStr;
 use std::net::{UdpSocket, ToSocketAddrs, Ipv4Addr, SocketAddr, SocketAddrV4};
 use std::os::unix::io::AsRawFd;
 
+use super::MAGIC;
 use super::cloud::GenericCloud;
 use super::device::{Device, Type};
-use super::udpmessage::{Options, Message, encode, decode};
+use super::udpmessage::{Message, encode, decode};
 use super::crypto::{Crypto, CryptoMethod};
 use super::ethernet::{Frame, SwitchTable};
 use super::types::{Address, Table, Protocol};
@@ -51,27 +52,25 @@ fn crypto_aes256(b: &mut Bencher) {
 
 #[bench]
 fn message_encode(b: &mut Bencher) {
-    let mut options = Options::default();
     let mut crypto = Crypto::None;
     let mut payload = [0; 1600];
     let mut msg = Message::Data(&mut payload, 64, 1464);
     let mut buf = [0; 1600];
     b.iter(|| {
-        encode(&mut options, &mut msg, &mut buf[..], &mut crypto);
+        encode(&mut msg, &mut buf[..], MAGIC, &mut crypto);
     });
     b.bytes = 1400;
 }
 
 #[bench]
 fn message_decode(b: &mut Bencher) {
-    let mut options = Options::default();
     let mut crypto = Crypto::None;
     let mut payload = [0; 1600];
     let mut msg = Message::Data(&mut payload, 64, 1464);
     let mut buf = [0; 1600];
-    let mut res = encode(&mut options, &mut msg, &mut buf[..], &mut crypto);
+    let mut res = encode(&mut msg, &mut buf[..], MAGIC, &mut crypto);
     b.iter(|| {
-        decode(&mut res, &mut crypto).unwrap();
+        decode(&mut res, MAGIC, &mut crypto).unwrap();
     });
     b.bytes = 1400;
 }
@@ -152,7 +151,7 @@ fn epoll_wait(b: &mut Bencher) {
 #[bench]
 fn handle_interface_data(b: &mut Bencher) {
     let mut node = GenericCloud::<Frame>::new(
-        Device::dummy("vpncloud0", "/dev/null", Type::Tap).unwrap(), 0, None,
+        MAGIC, Device::dummy("vpncloud0", "/dev/null", Type::Tap).unwrap(), 0,
         Box::new(SwitchTable::new(300)), 1800, true, true, vec![], Crypto::None
     );
     let mut data = [0; 1500];
@@ -166,14 +165,14 @@ fn handle_interface_data(b: &mut Bencher) {
 #[bench]
 fn handle_net_message(b: &mut Bencher) {
     let mut node = GenericCloud::<Frame>::new(
-        Device::dummy("vpncloud0", "/dev/null", Type::Tap).unwrap(), 0, None,
+        MAGIC, Device::dummy("vpncloud0", "/dev/null", Type::Tap).unwrap(), 0,
         Box::new(SwitchTable::new(300)), 1800, true, true, vec![], Crypto::None
     );
     let addr = SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 1));
     let mut data = [0; 1500];
     data[105] = 45;
     b.iter(|| {
-        node.handle_net_message(addr.clone(), Options::default(), Message::Data(&mut data, 0, 1400)).unwrap()
+        node.handle_net_message(addr.clone(), Message::Data(&mut data, 0, 1400)).unwrap()
     });
     b.bytes = 1400;
 }

src/cloud.rs

@@ -19,9 +19,9 @@ use signal::trap::Trap;
 use rand::{random, sample, thread_rng};
 use net2::UdpBuilder;
 
-use super::types::{Table, Protocol, Range, Error, NetworkId, NodeId};
+use super::types::{Table, Protocol, Range, Error, HeaderMagic, NodeId};
 use super::device::Device;
-use super::udpmessage::{encode, decode, Options, Message};
+use super::udpmessage::{encode, decode, Message};
 use super::crypto::Crypto;
 use super::util::{now, Time, Duration, resolve};
 use super::poll::{self, Poll};
@@ -153,6 +153,7 @@ pub struct ReconnectEntry {
 }
 
 pub struct GenericCloud<P: Protocol> {
+    magic: HeaderMagic,
     node_id: NodeId,
     peers: PeerList,
     addresses: Vec<Range>,
@@ -164,7 +165,6 @@ pub struct GenericCloud<P: Protocol> {
     socket4: UdpSocket,
     socket6: UdpSocket,
     device: Device,
-    options: Options,
     crypto: Crypto,
     next_peerlist: Time,
     update_freq: Duration,
@@ -176,7 +176,7 @@ pub struct GenericCloud<P: Protocol> {
 impl<P: Protocol> GenericCloud<P> {
     #[allow(unknown_lints)]
     #[allow(too_many_arguments)]
-    pub fn new(device: Device, listen: u16, network_id: Option<NetworkId>, table: Box<Table>,
+    pub fn new(magic: HeaderMagic, device: Device, listen: u16, table: Box<Table>,
         peer_timeout: Duration, learning: bool, broadcast: bool, addresses: Vec<Range>,
         crypto: Crypto) -> Self {
         let socket4 = match UdpBuilder::new_v4().expect("Failed to obtain ipv4 socket builder")
@@ -190,9 +190,8 @@ impl<P: Protocol> GenericCloud<P> {
             Ok(socket) => socket,
             Err(err) => fail!("Failed to open ipv6 address ::{}: {}", listen, err)
         };
-        let mut options = Options::default();
-        options.network_id = network_id;
         GenericCloud{
+            magic: magic,
             node_id: random(),
             peers: PeerList::new(peer_timeout),
             addresses: addresses,
@@ -204,7 +203,6 @@ impl<P: Protocol> GenericCloud<P> {
             socket4: socket4,
             socket6: socket6,
             device: device,
-            options: options,
             crypto: crypto,
             next_peerlist: now(),
             update_freq: peer_timeout/2-60,
@@ -229,7 +227,7 @@ impl<P: Protocol> GenericCloud<P> {
     fn broadcast_msg(&mut self, msg: &mut Message) -> Result<(), Error> {
         debug!("Broadcasting {:?}", msg);
         // Encrypt and encode once and send several times
-        let msg_data = encode(&self.options, msg, &mut self.buffer_out, &mut self.crypto);
+        let msg_data = encode(msg, &mut self.buffer_out, self.magic, &mut self.crypto);
         for addr in self.peers.as_vec() {
             let socket = match addr {
                 SocketAddr::V4(_) => &self.socket4,
@@ -256,7 +254,7 @@ impl<P: Protocol> GenericCloud<P> {
     fn send_msg(&mut self, addr: SocketAddr, msg: &mut Message) -> Result<(), Error> {
         debug!("Sending {:?} to {}", msg, addr);
         // Encrypt and encode
-        let msg_data = encode(&self.options, msg, &mut self.buffer_out, &mut self.crypto);
+        let msg_data = encode(msg, &mut self.buffer_out, self.magic, &mut self.crypto);
         let socket = match addr {
             SocketAddr::V4(_) => &self.socket4,
             SocketAddr::V6(_) => &self.socket6
@@ -456,11 +454,7 @@ impl<P: Protocol> GenericCloud<P> {
     /// Handles a message received from the network
     ///
     /// This method handles messages from the network, i.e. from peers. `peer` contains the sender
-    /// of the message. `options` contains the options from the message and `msg` contains the
+    /// of the message and `msg` contains the message.
-    /// message.
-    ///
-    /// If the `network_id` in the messages options differs from the `network_id` of this node,
-    /// the message is simply ignored.
     ///
     /// Then this method will check the message type and will handle each message type differently.
     ///
@@ -490,11 +484,7 @@ impl<P: Protocol> GenericCloud<P> {
     /// # `Message::Close` message
     /// If this message is received, the sender is removed from the peer list and its claimed
     /// addresses are removed from the table.
-    pub fn handle_net_message(&mut self, peer: SocketAddr, options: Options, msg: Message) -> Result<(), Error> {
+    pub fn handle_net_message(&mut self, peer: SocketAddr, msg: Message) -> Result<(), Error> {
-        if self.options.network_id != options.network_id {
-            info!("Ignoring message from {} with wrong token {:?}", peer, options.network_id);
-            return Err(Error::WrongNetwork(options.network_id));
-        }
         debug!("Received {:?} from {}", msg, peer);
         match msg {
             Message::Data(payload, start, end) => {
@@ -583,7 +573,7 @@ impl<P: Protocol> GenericCloud<P> {
                             fd if fd == socket6_fd => try_fail!(self.socket6.recv_from(&mut buffer), "Failed to read from ipv6 network socket: {}"),
                             _ => unreachable!()
                         };
-                        if let Err(e) = decode(&mut buffer[..size], &mut self.crypto).and_then(|(options, msg)| self.handle_net_message(src, options, msg)) {
+                        if let Err(e) = decode(&mut buffer[..size], self.magic, &mut self.crypto).and_then(|msg| self.handle_net_message(src, msg)) {
                             error!("Error: {}, from: {}", e, src);
                         }
                     },

src/main.rs

@@ -39,11 +39,14 @@ use std::process::Command;
 use device::{Device, Type};
 use ethernet::SwitchTable;
 use ip::RoutingTable;
-use types::{Mode, Range, Table, Protocol};
+use types::{Mode, Range, Table, Protocol, HeaderMagic};
 use cloud::GenericCloud;
-use udpmessage::VERSION;
 use crypto::{Crypto, CryptoMethod};
-use util::Duration;
+use util::{Duration, Encoder};
+
+
+const VERSION: u8 = 1;
+const MAGIC: HeaderMagic = *b"vpn\x01";
 
 
 struct SimpleLogger;
@@ -74,6 +77,7 @@ struct Args {
     flag_device: String,
     flag_listen: u16,
     flag_network_id: Option<String>,
+    flag_magic: Option<String>,
     flag_connect: Vec<String>,
     flag_peer_timeout: Duration,
     flag_dst_timeout: Duration,
@@ -98,7 +102,7 @@ fn run_script(script: String, ifname: &str) {
     }
 }
 
-fn run<T: Protocol> (args: Args) {
+fn run<T: Protocol> (mut args: Args) {
     let device = try_fail!(Device::new(&args.flag_device, args.flag_type),
         "Failed to open virtual {} interface {}: {}", args.flag_type, &args.flag_device);
     info!("Opened device {}", device.ifname());
@@ -117,17 +121,32 @@ fn run<T: Protocol> (args: Args) {
         Mode::Switch => (true, true, Box::new(SwitchTable::new(dst_timeout))),
         Mode::Hub => (false, true, Box::new(SwitchTable::new(dst_timeout)))
     };
-    let network_id = args.flag_network_id.map(|name| {
+    if let Some(network_id) = args.flag_network_id {
+        warn!("The --network-id argument is deprecated, please use --magic instead.");
+        if args.flag_magic.is_none() {
+            args.flag_magic = Some(network_id);
+        }
+    }
+    let magic = args.flag_magic.map_or(MAGIC, |name| {
+        if name.starts_with("hash:") {
             let mut s = SipHasher::new();
-        name.hash(&mut s);
+            name[6..].hash(&mut s);
-        s.finish()
+            let mut data = [0; 4];
+            Encoder::write_u32((s.finish() & 0xffffffff) as u32, &mut data);
+            data
+        } else {
+            let num = try_fail!(u32::from_str_radix(&name, 16), "Failed to parse header magic: {}");
+            let mut data = [0; 4];
+            Encoder::write_u32(num, &mut data);
+            data
+        }
     });
     Crypto::init();
     let crypto = match args.flag_shared_key {
         Some(key) => Crypto::from_shared_key(args.flag_crypto, &key),
         None => Crypto::None
     };
-    let mut cloud = GenericCloud::<T>::new(device, args.flag_listen, network_id, table, peer_timeout, learning, broadcasting, ranges, crypto);
+    let mut cloud = GenericCloud::<T>::new(magic, device, args.flag_listen, table, peer_timeout, learning, broadcasting, ranges, crypto);
     if let Some(script) = args.flag_ifup {
         run_script(script, cloud.ifname());
     }

src/tests.rs

@@ -5,10 +5,11 @@
 use std::net::{ToSocketAddrs, SocketAddr};
 use std::str::FromStr;
 
+use super::MAGIC;
 use super::ethernet::{Frame, SwitchTable};
 use super::ip::{RoutingTable, Packet};
 use super::types::{Protocol, Address, Range, Table};
-use super::udpmessage::{Options, Message, decode, encode};
+use super::udpmessage::{Message, decode, encode};
 use super::crypto::{Crypto, CryptoMethod};
 
 
@@ -34,7 +35,6 @@ impl<'a> PartialEq for Message<'a> {
 #[test]
 #[allow(unused_assignments)]
 fn udpmessage_packet() {
-    let mut options = Options::default();
     let mut crypto = Crypto::None;
     let mut payload = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
@@ -45,7 +45,7 @@ fn udpmessage_packet() {
     let mut buf = [0; 1024];
     let mut len = 0;
     {
-        let res = encode(&mut options, &mut msg, &mut [], &mut crypto);
+        let res = encode(&mut msg, &mut [], MAGIC, &mut crypto);
         assert_eq!(res.len(), 13);
         assert_eq!(&res[..8], &[118,112,110,1,0,0,0,0]);
         for i in 0..res.len() {
@@ -53,15 +53,13 @@ fn udpmessage_packet() {
         }
         len = res.len();
     }
-    let (options2, msg2) = decode(&mut buf[..len], &mut crypto).unwrap();
+    let msg2 = decode(&mut buf[..len], MAGIC, &mut crypto).unwrap();
-    assert_eq!(options, options2);
     assert_eq!(msg, msg2);
 }
 
 #[test]
 #[allow(unused_assignments)]
 fn udpmessage_encrypted() {
-    let mut options = Options::default();
     let mut crypto = Crypto::from_shared_key(CryptoMethod::ChaCha20, "test");
     let mut payload = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
@@ -77,7 +75,7 @@ fn udpmessage_encrypted() {
     let mut buf = [0; 1024];
     let mut len = 0;
     {
-        let res = encode(&mut options, &mut msg, &mut [], &mut crypto);
+        let res = encode(&mut msg, &mut [], MAGIC, &mut crypto);
         assert_eq!(res.len(), 41);
         assert_eq!(&res[..8], &[118,112,110,1,1,0,0,0]);
         for i in 0..res.len() {
@@ -85,62 +83,40 @@ fn udpmessage_encrypted() {
         }
         len = res.len();
     }
-    let (options2, msg2) = decode(&mut buf[..len], &mut crypto).unwrap();
+    let msg2 = decode(&mut buf[..len], MAGIC, &mut crypto).unwrap();
-    assert_eq!(options, options2);
     assert_eq!(orig_msg, msg2);
 }
 
 #[test]
 fn udpmessage_peers() {
     use std::str::FromStr;
-    let mut options = Options::default();
     let mut crypto = Crypto::None;
     let mut msg = Message::Peers(vec![SocketAddr::from_str("1.2.3.4:123").unwrap(), SocketAddr::from_str("5.6.7.8:12345").unwrap(), SocketAddr::from_str("[0001:0203:0405:0607:0809:0a0b:0c0d:0e0f]:6789").unwrap()]);
     let mut should = [118,112,110,1,0,0,0,1,2,1,2,3,4,0,123,5,6,7,8,48,57,1,0,1,2,3,4,5,6,7,
         8,9,10,11,12,13,14,15,26,133];
     {
         let mut buf = [0; 1024];
-        let res = encode(&mut options, &mut msg, &mut buf[..], &mut crypto);
+        let res = encode(&mut msg, &mut buf[..], MAGIC, &mut crypto);
         assert_eq!(res.len(), 40);
         for i in 0..res.len() {
             assert_eq!(res[i], should[i]);
         }
     }
-    let (options2, msg2) = decode(&mut should, &mut crypto).unwrap();
+    let msg2 = decode(&mut should, MAGIC, &mut crypto).unwrap();
-    assert_eq!(options, options2);
     assert_eq!(msg, msg2);
     // Missing IPv4 count
-    assert!(decode(&mut[118,112,110,1,0,0,0,1], &mut crypto).is_err());
+    assert!(decode(&mut[118,112,110,1,0,0,0,1], MAGIC, &mut crypto).is_err());
     // Truncated IPv4
-    assert!(decode(&mut[118,112,110,1,0,0,0,1,1], &mut crypto).is_err());
+    assert!(decode(&mut[118,112,110,1,0,0,0,1,1], MAGIC, &mut crypto).is_err());
     // Missing IPv6 count
-    assert!(decode(&mut[118,112,110,1,0,0,0,1,1,1,2,3,4,0,0], &mut crypto).is_err());
+    assert!(decode(&mut[118,112,110,1,0,0,0,1,1,1,2,3,4,0,0], MAGIC, &mut crypto).is_err());
     // Truncated IPv6
-    assert!(decode(&mut[118,112,110,1,0,0,0,1,1,1,2,3,4,0,0,1], &mut crypto).is_err());
+    assert!(decode(&mut[118,112,110,1,0,0,0,1,1,1,2,3,4,0,0,1], MAGIC, &mut crypto).is_err());
-}
-
-#[test]
-fn udpmessage_option_network_id() {
-    let mut options = Options::default();
-    options.network_id = Some(134);
-    let mut crypto = Crypto::None;
-    let mut msg = Message::Close;
-    let mut should = [118,112,110,1,0,0,1,3,0,0,0,0,0,0,0,134];
-    {
-        let mut buf = [0; 1024];
-        let res = encode(&mut options, &mut msg, &mut buf[..], &mut crypto);
-        assert_eq!(res.len(), 16);
-        assert_eq!(&res, &should);
-    }
-    let (options2, msg2) = decode(&mut should, &mut crypto).unwrap();
-    assert_eq!(options, options2);
-    assert_eq!(msg, msg2);
 }
 
 #[test]
 fn udpmessage_init() {
     use super::types::Address;
-    let mut options = Options::default();
     let mut crypto = Crypto::None;
     let addrs = vec![Range{base: Address{data: [0,1,2,3,0,0,0,0,0,0,0,0,0,0,0,0], len: 4}, prefix_len: 24},
         Range{base: Address{data: [0,1,2,3,4,5,0,0,0,0,0,0,0,0,0,0], len: 6}, prefix_len: 16}];
@@ -149,57 +125,52 @@ fn udpmessage_init() {
     let mut should = [118,112,110,1,0,0,0,2,0,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,2,4,0,1,2,3,24,6,0,1,2,3,4,5,16];
     {
         let mut buf = [0; 1024];
-        let res = encode(&mut options, &mut msg, &mut buf[..], &mut crypto);
+        let res = encode(&mut msg, &mut buf[..], MAGIC, &mut crypto);
         assert_eq!(res.len(), 40);
         for i in 0..res.len() {
             assert_eq!(res[i], should[i]);
         }
     }
-    let (options2, msg2) = decode(&mut should, &mut crypto).unwrap();
+    let msg2 = decode(&mut should, MAGIC, &mut crypto).unwrap();
-    assert_eq!(options, options2);
     assert_eq!(msg, msg2);
 }
 
 #[test]
 fn udpmessage_close() {
-    let mut options = Options::default();
     let mut crypto = Crypto::None;
     let mut msg = Message::Close;
     let mut should = [118,112,110,1,0,0,0,3];
     {
         let mut buf = [0; 1024];
-        let res = encode(&mut options, &mut msg, &mut buf[..], &mut crypto);
+        let res = encode(&mut msg, &mut buf[..], MAGIC, &mut crypto);
         assert_eq!(res.len(), 8);
         assert_eq!(&res, &should);
     }
-    let (options2, msg2) = decode(&mut should, &mut crypto).unwrap();
+    let msg2 = decode(&mut should, MAGIC, &mut crypto).unwrap();
-    assert_eq!(options, options2);
     assert_eq!(msg, msg2);
 }
 
 #[test]
 fn udpmessage_invalid() {
     let mut crypto = Crypto::None;
-    assert!(decode(&mut [0x76,0x70,0x6e,1,0,0,0,0], &mut crypto).is_ok());
+    assert!(decode(&mut [0x76,0x70,0x6e,1,0,0,0,0], MAGIC, &mut crypto).is_ok());
     // too short
-    assert!(decode(&mut [], &mut crypto).is_err());
+    assert!(decode(&mut [], MAGIC, &mut crypto).is_err());
     // invalid protocol
-    assert!(decode(&mut [0,1,2,0,0,0,0,0], &mut crypto).is_err());
+    assert!(decode(&mut [0,1,2,0,0,0,0,0], MAGIC, &mut crypto).is_err());
     // invalid version
-    assert!(decode(&mut [0x76,0x70,0x6e,0xaa,0,0,0,0], &mut crypto).is_err());
+    assert!(decode(&mut [0x76,0x70,0x6e,0xaa,0,0,0,0], MAGIC, &mut crypto).is_err());
     // invalid crypto
-    assert!(decode(&mut [0x76,0x70,0x6e,1,0xaa,0,0,0], &mut crypto).is_err());
+    assert!(decode(&mut [0x76,0x70,0x6e,1,0xaa,0,0,0], MAGIC, &mut crypto).is_err());
     // invalid msg type
-    assert!(decode(&mut [0x76,0x70,0x6e,1,0,0,0,0xaa], &mut crypto).is_err());
+    assert!(decode(&mut [0x76,0x70,0x6e,1,0,0,0,0xaa], MAGIC, &mut crypto).is_err());
-    // truncated options
-    assert!(decode(&mut [0x76,0x70,0x6e,1,0,0,1,0], &mut crypto).is_err());
 }
 
 #[test]
 fn udpmessage_invalid_crypto() {
     let mut crypto = Crypto::from_shared_key(CryptoMethod::ChaCha20, "test");
     // truncated crypto
-    assert!(decode(&mut [0x76,0x70,0x6e,1,1,0,0,0], &mut crypto).is_err());
+    assert!(decode(&mut [0x76,0x70,0x6e,1,1,0,0,0], MAGIC, &mut crypto).is_err());
 }
 
 

src/types.rs

@@ -12,7 +12,7 @@ use super::util::{bytes_to_hex, Encoder};
 
 pub const NODE_ID_BYTES: usize = 16;
 
-pub type NetworkId = u64;
+pub type HeaderMagic = [u8; 4];
 pub type NodeId = [u8; NODE_ID_BYTES];
 
 
@@ -215,7 +215,7 @@ pub trait Protocol: Sized {
 #[derive(Debug)]
 pub enum Error {
     Parse(&'static str),
-    WrongNetwork(Option<NetworkId>),
+    WrongHeaderMagic(HeaderMagic),
     Socket(&'static str, io::Error),
     Name(String),
     TunTapDev(&'static str, io::Error),
@@ -229,8 +229,7 @@ impl fmt::Display for Error {
             Error::TunTapDev(ref msg, ref err) => write!(formatter, "{}: {:?}", msg, err),
             Error::Crypto(ref msg) => write!(formatter, "{}", msg),
             Error::Name(ref name) => write!(formatter, "failed to resolve name '{}'", name),
-            Error::WrongNetwork(Some(net)) => write!(formatter, "wrong network id: {}", net),
+            Error::WrongHeaderMagic(net) => write!(formatter, "wrong header magic: {}", bytes_to_hex(&net)),
-            Error::WrongNetwork(None) => write!(formatter, "wrong network id: none"),
         }
     }
 }

src/udpmessage.rs

@@ -5,23 +5,17 @@
 use std::fmt;
 use std::net::{SocketAddr, SocketAddrV4, Ipv4Addr, SocketAddrV6, Ipv6Addr};
 
-use super::types::{NodeId, Error, NetworkId, Range, NODE_ID_BYTES};
+use super::types::{NodeId, HeaderMagic, Error, Range, NODE_ID_BYTES};
 use super::util::{bytes_to_hex, Encoder};
 use super::crypto::Crypto;
 
-const MAGIC: [u8; 3] = *b"vpn";
+#[derive(Clone, Copy, Default)]
-pub const VERSION: u8 = 1;
-
-const NETWORK_ID_BYTES: usize = 8;
-
-#[derive(Clone, Copy)]
 #[repr(packed)]
 struct TopHeader {
-    magic: [u8; 3],
+    magic: HeaderMagic,
-    version: u8,
     crypto_method : u8,
-    _reserved: u8,
+    _reserved1: u8,
-    flags: u8,
+    _reserved2: u8,
     msgtype: u8
 }
 
@@ -36,35 +30,20 @@ impl TopHeader {
             return Err(Error::Parse("Empty message"));
         }
         let mut header = TopHeader::default();
-        header.magic.copy_from_slice(&data[0..3]);
+        header.magic.copy_from_slice(&data[0..4]);
-        header.version = data[3];
         header.crypto_method = data[4];
-        header.flags = data[6];
         header.msgtype = data[7];
         Ok((header, TopHeader::size()))
     }
 
     pub fn write_to(&self, data: &mut [u8]) -> usize {
-        data[0..3].copy_from_slice(&self.magic);
+        data[0..4].copy_from_slice(&self.magic);
-        data[3] = self.version;
         data[4] = self.crypto_method;
-        data[6] = self.flags;
         data[7] = self.msgtype;
         TopHeader::size()
     }
 }
 
-impl Default for TopHeader {
-    fn default() -> Self {
-        TopHeader{magic: MAGIC, version: VERSION, crypto_method: 0, _reserved: 0, flags: 0, msgtype: 0}
-    }
-}
-
-#[derive(Default, Debug, PartialEq, Eq, Clone, Copy)]
-pub struct Options {
-    pub network_id: Option<NetworkId>,
-}
-
 pub enum Message<'a> {
     Data(&'a mut[u8], usize, usize), // data, start, end
     Peers(Vec<SocketAddr>), // peers
@@ -96,14 +75,11 @@ impl<'a> fmt::Debug for Message<'a> {
 
 #[allow(unknown_lints)]
 #[allow(needless_range_loop)]
-pub fn decode<'a>(data: &'a mut [u8], crypto: &mut Crypto) -> Result<(Options, Message<'a>), Error> {
+pub fn decode<'a>(data: &'a mut [u8], magic: HeaderMagic, crypto: &mut Crypto) -> Result<Message<'a>, Error> {
     let mut end = data.len();
     let (header, mut pos) = try!(TopHeader::read_from(&data[..end]));
-    if header.magic != MAGIC {
+    if header.magic != magic {
-        return Err(Error::Parse("Wrong protocol"));
+        return Err(Error::WrongHeaderMagic(header.magic));
-    }
-    if header.version != VERSION {
-        return Err(Error::Parse("Wrong version"));
     }
     if header.crypto_method != crypto.method() {
         return Err(Error::Crypto("Wrong crypto method"));
@@ -121,14 +97,6 @@ pub fn decode<'a>(data: &'a mut [u8], crypto: &mut Crypto) -> Result<(Options, M
         }
         assert_eq!(end, data.len()-crypto.additional_bytes());
     }
-    let mut options = Options::default();
-    if header.flags & 0x01 > 0 {
-        if end < pos + NETWORK_ID_BYTES {
-            return Err(Error::Parse("Truncated options"));
-        }
-        options.network_id = Some(Encoder::read_u64(&data[pos..pos+NETWORK_ID_BYTES]));
-        pos += NETWORK_ID_BYTES;
-    }
     let msg = match header.msgtype {
         0 => Message::Data(data, pos, end),
         1 => {
@@ -195,12 +163,12 @@ pub fn decode<'a>(data: &'a mut [u8], crypto: &mut Crypto) -> Result<(Options, M
         3 => Message::Close,
         _ => return Err(Error::Parse("Unknown message type"))
     };
-    Ok((options, msg))
+    Ok(msg)
 }
 
 #[allow(unknown_lints)]
 #[allow(needless_range_loop)]
-pub fn encode<'a>(options: &Options, msg: &'a mut Message, mut buf: &'a mut [u8], crypto: &mut Crypto) -> &'a mut [u8] {
+pub fn encode<'a>(msg: &'a mut Message, mut buf: &'a mut [u8], magic: HeaderMagic, crypto: &mut Crypto) -> &'a mut [u8] {
     let mut start = 64;
     let mut end = 64;
     match *msg {
@@ -264,14 +232,10 @@ pub fn encode<'a>(options: &Options, msg: &'a mut Message, mut buf: &'a mut [u8]
     }
     assert!(start >= 64);
     assert!(buf.len() >= end + 64);
-    if let Some(id) = options.network_id {
-        assert!(start >= NETWORK_ID_BYTES);
-        Encoder::write_u64(id, &mut buf[start-NETWORK_ID_BYTES..]);
-        start -= NETWORK_ID_BYTES;
-    }
     let crypto_start = start;
     start -= crypto.nonce_bytes();
     let mut header = TopHeader::default();
+    header.magic = magic;
     header.msgtype = match *msg {
         Message::Data(_, _, _) => 0,
         Message::Peers(_) => 1,
@@ -279,9 +243,6 @@ pub fn encode<'a>(options: &Options, msg: &'a mut Message, mut buf: &'a mut [u8]
         Message::Close => 3
     };
     header.crypto_method = crypto.method();
-    if options.network_id.is_some() {
-        header.flags |= 0x01;
-    }
     start -= TopHeader::size();
     header.write_to(&mut buf[start..]);
     if crypto.method() > 0 {

src/usage.txt

@@ -12,7 +12,10 @@ Options:
                                     [default: 3210]
     -c <addr>, --connect <addr>     Address of a peer to connect to.
     -s <addr>, --subnet <subnet>    The local subnets to use.
+    --magic <hex>                   Override the 4-byte magic header of each
+                                    packet.
     --network-id <id>               Optional token that identifies the network.
+                                    (DEPRECATED)
     --shared-key <key>              The shared key to encrypt all traffic.
     --crypto <method>               The encryption method to use ("aes256", or
                                     "chacha20"). [default: chacha20]

src/util.rs

@@ -58,6 +58,20 @@ impl Encoder {
         data[1] = (val & 0xff) as u8;
     }
 
+    #[inline]
+    pub fn read_u32(data: &[u8]) -> u32 {
+        ((data[0] as u32) << 24) | ((data[1] as u32) << 16) |
+        ((data[2] as u32) << 8) | data[3] as u32
+    }
+
+    #[inline]
+    pub fn write_u32(val: u32, data: &mut [u8]) {
+        data[0] = ((val >> 24) & 0xff) as u8;
+        data[1] = ((val >> 16) & 0xff) as u8;
+        data[2] = ((val >> 8) & 0xff) as u8;
+        data[3] = (val & 0xff) as u8;
+    }
+
     #[inline]
     pub fn read_u64(data: &[u8]) -> u64 {
         ((data[0] as u64) << 56) | ((data[1] as u64) << 48) |

vpncloud.md

@@ -56,10 +56,13 @@ vpncloud(1) -- Peer-to-peer VPN
     computers lacking this support, only CHACHA20 is supported.
     [default: `chacha20`]
 
-  * `--network-id <id>`:
+  * `--magic <id>`:
 
-    An optional token that identifies the network and helps to distinguish it
+    Override the 4-byte magic header of each packet. This header identifies the
-    from other networks.
+    network and helps to distinguish it from other networks and other
+    applications. The id can either be a 4 byte / 8 character hexadecimal
+    string or an arbitrary string prefixed with "hash:" which will then be
+    hashed into 4 bytes.
 
   * `--peer-timeout <secs>`:
 
@@ -129,8 +132,8 @@ and to allow the automatic cross-connect behavior. There are some important
 things to note:
 
   - To avoid that different networks that reuse each others addresses merge due
-    to the cross-connect behavior, the `network_id` option can be used and set
+    to the cross-connect behavior, the `magic` option can be used and set
-    to any unique string to identify the network. The `network_id` must be the
+    to any unique string to identify the network. The `magic` must be the
     same on all nodes of the same VPN network.
 
   - The cross-connect behavior can be able to connect nodes that are behind
@@ -203,7 +206,7 @@ vpncloud -t tun -c REMOTE_HOST:PORT --subnet 10.0.0.X/32 --ifup 'ifconfig $IFNAM
   The shared key is hashed using *ScryptSalsa208Sha256* to derive a key,
   which is used to encrypt the payload of messages using *ChaCha20Poly1305* or
   *AES256-GCM*. The encryption includes an authentication that also protects the
-  header and all additional headers.
+  header.
   This method does only protect against attacks on single messages but not
   against attacks that manipulate the message series itself (i.e. suppress
   messages, reorder them, or duplicate them).
@@ -216,21 +219,17 @@ implementations and to maximize the performance.
 
 Every packet sent over UDP contains the following header (in order):
 
-  * 3 bytes `magic constant` = `[0x76, 0x70, 0x6e]` ("vpn")
+  * 4 bytes `magic`
 
     This field is used to identify the packet and to sort out packets that do
-    not belong.
+    not belong. The default is `[0x76, 0x70, 0x6e, 0x01]` ("vpn\x01").
-
+    This field can be used to identify VpnCloud packets and might be set to
-  * 1 byte `version number` = 1 (currently)
+    something different to hide the protocol.
-
-    This field specifies the version and helps nodes to parse the rest of the
-    header and the packet.
 
   * 1 byte `crypto method`
 
     This field specifies the method that must be used to decrypt the rest of the
-    data (additional headers and message contents). The currently supported
+    data. The currently supported methods are:
-    methods are:
 
     - Method `0`, **No encryption**: Rest of the data can be read without
       decrypting it.
@@ -245,21 +244,12 @@ Every packet sent over UDP contains the following header (in order):
       `libsodium::crypto_aead_aes256gcm` method, using the 8 byte header
       as additional data.
 
-  * 1 `reserved byte` that is currently unused
+  * 2 `reserved bytes` that are currently unused
-
-  * 1 byte for `flags`
-
-    This byte contains flags that specify the presence of additional headers.
-    The flags are enumerated from bit 1 (least significant bit) to bit 8
-    (most significant bit). The additional headers must be present in this same
-    order. Currently the following additional headers are supported:
-
-    - Bit 1: Network ID
 
   * 1 byte for the `message type`
 
-    This byte specifies the type of message that follows after all additional
+    This byte specifies the type of message that follows. Currently the
-    headers. Currently the following message types are supported:
+    following message types are supported:
 
     - Type 0: Data packet
     - Type 1: Peer list
@@ -269,21 +259,14 @@ Every packet sent over UDP contains the following header (in order):
 After this 8 byte header, the rest of the message follows. It is encrypted using
 the method specified in the header.
 
-In the decrypted data, the additional headers as specified in the `flags` field
+In the decrypted data, the message as specified in the `message type` field
-will follow in the order of their respective flag bits.
+will follow:
-
-  * **Network ID**:
-
-    The network id is encoded as 8 bytes.
-
-After the additional headers, the message as specified in the `message type`
-field will follow:
 
   * **Data packet** (message type 0):
     This packet contains payload. The format of the data depends on the device
     type. For TUN devices, this data contains an IP packet. For TAP devices it
-    contains an Ethernet frame. The data starts right after all additional
+    contains an Ethernet frame. The data starts right after the header and ends
-    headers and ends at the end of the packet.
+    at the end of the packet.
     If it is an Ethernet frame, it will start with the destination MAC and end
     with the payload. It does not contain the preamble, SFD, padding, and CRC
     fields.