vpncloud/src/cloud.rs

620 lines
24 KiB
Rust

// VpnCloud - Peer-to-Peer VPN
// Copyright (C) 2015-2016 Dennis Schwerdel
// This software is licensed under GPL-3 or newer (see LICENSE.md)
use std::net::{SocketAddr, ToSocketAddrs};
use std::collections::{HashMap, HashSet};
use std::net::UdpSocket;
use std::io;
use std::fmt;
use std::os::unix::io::AsRawFd;
use std::marker::PhantomData;
use std::hash::BuildHasherDefault;
use std::time::Instant;
use std::cmp::{min, max};
use fnv::FnvHasher;
use nix::sys::signal::{SIGTERM, SIGQUIT, SIGINT};
use signal::trap::Trap;
use rand::{random, sample, thread_rng};
use net2::UdpBuilder;
use super::types::{Table, Protocol, Range, Error, NetworkId, NodeId};
use super::device::Device;
use super::udpmessage::{encode, decode, Options, Message};
use super::crypto::Crypto;
use super::util::{now, Time, Duration, resolve};
use super::poll::{self, Poll};
type Hash = BuildHasherDefault<FnvHasher>;
struct PeerList {
timeout: Duration,
peers: HashMap<SocketAddr, (Time, NodeId, Vec<SocketAddr>), Hash>,
nodes: HashMap<NodeId, SocketAddr, Hash>,
addresses: HashSet<SocketAddr, Hash>
}
impl PeerList {
fn new(timeout: Duration) -> PeerList {
PeerList{
peers: HashMap::default(),
timeout: timeout,
nodes: HashMap::default(),
addresses: HashSet::default()
}
}
fn timeout(&mut self) -> Vec<SocketAddr> {
let now = now();
let mut del: Vec<SocketAddr> = Vec::new();
for (&addr, &(timeout, _nodeid, ref _alt_addrs)) in &self.peers {
if timeout < now {
del.push(addr);
}
}
for addr in &del {
debug!("Forgot peer: {}", addr);
if let Some((_timeout, nodeid, alt_addrs)) = self.peers.remove(addr) {
self.nodes.remove(&nodeid);
self.addresses.remove(addr);
for addr in &alt_addrs {
self.addresses.remove(addr);
}
}
}
del
}
#[inline]
fn contains_addr(&self, addr: &SocketAddr) -> bool {
self.addresses.contains(addr)
}
#[inline]
fn is_connected<Addr: ToSocketAddrs+fmt::Display>(&self, addr: Addr) -> Result<bool, Error> {
for addr in try!(resolve(addr)) {
if self.contains_addr(&addr) {
return Ok(true);
}
}
Ok(false)
}
#[inline]
fn contains_node(&self, node_id: &NodeId) -> bool {
self.nodes.contains_key(node_id)
}
#[inline]
fn add(&mut self, node_id: NodeId, addr: SocketAddr) {
if self.nodes.insert(node_id, addr).is_none() {
info!("New peer: {}", addr);
self.peers.insert(addr, (now()+self.timeout as Time, node_id, vec![]));
self.addresses.insert(addr);
}
}
#[inline]
fn add_alt_addr(&mut self, node_id: NodeId, addr: SocketAddr) {
if let Some(main_addr) = self.nodes.get(&node_id) {
if let Some(&mut (_timeout, _node_id, ref mut alt_addrs)) = self.peers.get_mut(main_addr) {
alt_addrs.push(addr);
self.addresses.insert(addr);
} else {
error!("Main address for node is not connected");
}
} else {
error!("Node not connected");
}
}
#[inline]
fn as_vec(&self) -> Vec<SocketAddr> {
self.addresses.iter().cloned().collect()
}
#[inline]
fn len(&self) -> usize {
self.peers.len()
}
#[inline]
#[allow(dead_code)]
fn is_empty(&self) -> bool {
self.peers.is_empty()
}
#[inline]
fn subset(&self, size: usize) -> Vec<SocketAddr> {
sample(&mut thread_rng(), self.as_vec(), size)
}
#[inline]
fn remove(&mut self, addr: &SocketAddr) {
if let Some((_timeout, node_id, alt_addrs)) = self.peers.remove(addr) {
info!("Removed peer: {}", addr);
self.nodes.remove(&node_id);
self.addresses.remove(addr);
for addr in alt_addrs {
self.addresses.remove(&addr);
}
}
}
}
#[derive(Clone)]
pub struct ReconnectEntry {
address: String,
tries: u16,
timeout: u16,
next: Time
}
pub struct GenericCloud<P: Protocol> {
node_id: NodeId,
peers: PeerList,
addresses: Vec<Range>,
learning: bool,
broadcast: bool,
reconnect_peers: Vec<ReconnectEntry>,
blacklist_peers: Vec<SocketAddr>,
table: Box<Table>,
socket4: UdpSocket,
socket6: UdpSocket,
device: Device,
options: Options,
crypto: Crypto,
next_peerlist: Time,
update_freq: Duration,
buffer_out: [u8; 64*1024],
next_housekeep: Time,
_dummy_p: PhantomData<P>,
}
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>,
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")
.reuse_address(true).expect("Failed to set so_reuseaddr").bind(("0.0.0.0", listen)) {
Ok(socket) => socket,
Err(err) => fail!("Failed to open ipv4 address 0.0.0.0:{}: {}", listen, err)
};
let socket6 = match UdpBuilder::new_v6().expect("Failed to obtain ipv6 socket builder")
.only_v6(true).expect("Failed to set only_v6")
.reuse_address(true).expect("Failed to set so_reuseaddr").bind(("::", listen)) {
Ok(socket) => socket,
Err(err) => fail!("Failed to open ipv6 address ::{}: {}", listen, err)
};
let mut options = Options::default();
options.network_id = network_id;
GenericCloud{
node_id: random(),
peers: PeerList::new(peer_timeout),
addresses: addresses,
learning: learning,
broadcast: broadcast,
reconnect_peers: Vec::new(),
blacklist_peers: Vec::new(),
table: table,
socket4: socket4,
socket6: socket6,
device: device,
options: options,
crypto: crypto,
next_peerlist: now(),
update_freq: peer_timeout/2-60,
buffer_out: [0; 64*1024],
next_housekeep: now(),
_dummy_p: PhantomData,
}
}
#[inline]
pub fn ifname(&self) -> &str {
self.device.ifname()
}
/// Sends the message to all peers
///
/// # Errors
/// Returns an `Error::SocketError` when the underlying system call fails or only part of the
/// message could be sent (can this even happen?).
/// Some messages could have been sent.
#[inline]
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);
for addr in self.peers.as_vec() {
let socket = match addr {
SocketAddr::V4(_) => &self.socket4,
SocketAddr::V6(_) => &self.socket6
};
try!(match socket.send_to(msg_data, addr) {
Ok(written) if written == msg_data.len() => Ok(()),
Ok(_) => Err(Error::Socket("Sent out truncated packet")),
Err(e) => {
error!("Failed to send via network {:?}", e);
Err(Error::Socket("IOError when sending"))
}
})
}
Ok(())
}
/// Sends a message to one peer
///
/// # Errors
/// Returns an `Error::SocketError` when the underlying system call fails or only part of the
/// message could be sent (can this even happen?).
#[inline]
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 socket = match addr {
SocketAddr::V4(_) => &self.socket4,
SocketAddr::V6(_) => &self.socket6
};
match socket.send_to(msg_data, addr) {
Ok(written) if written == msg_data.len() => Ok(()),
Ok(_) => Err(Error::Socket("Sent out truncated packet")),
Err(e) => {
error!("Failed to send via network {:?}", e);
Err(Error::Socket("IOError when sending"))
}
}
}
/// Returns the self-perceived addresses (IPv4 and IPv6) of this node
///
/// Note that those addresses could be private addresses that are not reachable by other nodes,
/// or only some other nodes inside the same network.
///
/// # Errors
/// Returns an IOError if the underlying system call fails
#[allow(dead_code)]
pub fn address(&self) -> io::Result<(SocketAddr, SocketAddr)> {
Ok((try!(self.socket4.local_addr()), try!(self.socket6.local_addr())))
}
/// Returns the number of peers
#[allow(dead_code)]
pub fn peer_count(&self) -> usize {
self.peers.len()
}
/// Adds a peer to the reconnect list
///
/// This method adds a peer to the list of nodes to reconnect to. A periodic task will try to
/// connect to the peer if it is not already connected.
pub fn add_reconnect_peer(&mut self, add: String) {
self.reconnect_peers.push(ReconnectEntry {
address: add,
tries: 0,
timeout: 1,
next: now()
})
}
/// Returns whether the address is blacklisted
///
/// # Errors
/// Returns an `Error::SocketError` if the given address is a name that failed to resolve to
/// actual addresses.
fn is_blacklisted<Addr: ToSocketAddrs+fmt::Display>(&self, addr: Addr) -> Result<bool, Error> {
for addr in try!(resolve(addr)) {
if self.blacklist_peers.contains(&addr) {
return Ok(true);
}
}
Ok(false)
}
/// Connects to a node given by its address
///
/// This method connects to node by sending a `Message::Init` to it. If `addr` is a name that
/// resolves to multiple addresses, one message is sent to each of them.
/// If the node is already a connected peer or the address is blacklisted, no message is sent.
///
/// # Errors
/// This method returns `Error::NameError` if the address is a name that fails to resolve.
pub fn connect<Addr: ToSocketAddrs+fmt::Display+Clone>(&mut self, addr: Addr) -> Result<(), Error> {
if try!(self.peers.is_connected(addr.clone())) || try!(self.is_blacklisted(addr.clone())) {
return Ok(())
}
debug!("Connecting to {}", addr);
let subnets = self.addresses.clone();
let node_id = self.node_id;
// Send a message to each resolved address
for a in try!(resolve(addr)) {
// Ignore error this time
let mut msg = Message::Init(0, node_id, subnets.clone());
self.send_msg(a, &mut msg).ok();
}
Ok(())
}
/// Run all periodic housekeeping tasks
///
/// This method executes several tasks:
/// - Remove peers that have timed out
/// - Remove switch table entries that have timed out
/// - Periodically send the peers list to all peers
/// - Periodically reconnect to peers in the reconnect list
///
/// # Errors
/// This method returns errors if sending a message fails or resolving an address fails.
fn housekeep(&mut self) -> Result<(), Error> {
for peer in self.peers.timeout() {
self.table.remove_all(&peer);
}
self.table.housekeep();
// Periodically send peer list to peers
let now = now();
if self.next_peerlist <= now {
debug!("Send peer list to all peers");
let mut peer_num = self.peers.len();
// If the number of peers is high, send only a fraction of the full peer list to
// reduce the management traffic. The number of peers to send is the square root of the
// total number of peers.
if peer_num > 10 {
peer_num = max(10, min(255, (peer_num as f32).sqrt().ceil() as usize));
}
// Select that many peers...
let peers = self.peers.subset(peer_num);
// ...and send them to all peers
let mut msg = Message::Peers(peers);
try!(self.broadcast_msg(&mut msg));
// Reschedule for next update
self.next_peerlist = now + self.update_freq as Time;
}
// Connect to those reconnect_peers that are due
for entry in self.reconnect_peers.clone() {
if entry.next > now {
continue
}
try!(self.connect(&entry.address as &str));
}
for entry in &mut self.reconnect_peers {
// Schedule for next second if node is connected
if try!(self.peers.is_connected(&entry.address as &str)) {
entry.tries = 0;
entry.timeout = 1;
entry.next = now + 1;
continue
}
// Ignore if next attempt is already in the future
if entry.next > now {
continue
}
// Exponential backoff: every 10 tries, the interval doubles
entry.tries += 1;
if entry.tries > 10 {
entry.tries = 0;
entry.timeout *= 2;
}
// Maximum interval is one hour
if entry.timeout > 3600 {
entry.timeout = 3600;
}
// Schedule next connection attempt
entry.next = now + entry.timeout as Time;
}
Ok(())
}
/// Handles payload data coming in from the local network device
///
/// This method takes payload data received from the local device and parses it to obtain the
/// destination address. Then it checks the lookup table to get the peer for that destination
/// address. If a peer is found, the message is sent to it, otherwise the message is either
/// broadcast to all peers or dropped (depending on mode).
///
/// The parameter `payload` contains the payload data starting at position `start` and ending
/// at `end`. It is important that the buffer has enough space before the payload data to
/// prepend a header of max 64 bytes and enough space after the payload data to append a mac of
/// max 64 bytes.
///
/// # Errors
/// This method fails
/// - with `Error::ParseError` if the payload data failed to parse
/// - with `Error::SocketError` if sending a message fails
pub fn handle_interface_data(&mut self, payload: &mut [u8], start: usize, end: usize) -> Result<(), Error> {
let (src, dst) = try!(P::parse(&payload[start..end]));
debug!("Read data from interface: src: {}, dst: {}, {} bytes", src, dst, end-start);
match self.table.lookup(&dst) {
Some(addr) => { // Peer found for destination
debug!("Found destination for {} => {}", dst, addr);
try!(self.send_msg(addr, &mut Message::Data(payload, start, end)));
if !self.peers.contains_addr(&addr) {
// If the peer is not actually conected, remove the entry in the table and try
// to reconnect.
warn!("Destination for {} not found in peers: {}", dst, addr);
self.table.remove(&dst);
try!(self.connect(&addr));
}
},
None => {
if self.broadcast {
debug!("No destination for {} found, broadcasting", dst);
let mut msg = Message::Data(payload, start, end);
try!(self.broadcast_msg(&mut msg));
} else {
debug!("No destination for {} found, dropping", dst);
}
}
}
Ok(())
}
/// 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
/// 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.
///
/// # `Message::Data` messages
/// This message type contains payload data and therefore this path is optimized for speed.
///
/// The payload of data messages is written to the local network device and if the node is in
/// a learning mode it will associate the sender peer with the source address.
///
/// # `Message::Peers` messages
/// If this message is received, the local node will use all the node addresses in the message
/// as well as the senders address to connect to.
///
/// # `Message::Init` messages
/// This message is used in the peer connection handshake.
///
/// To make sure, the node does not connect to itself, it will compare the remote `node_id` to
/// the local one. If the id is the same, it will ignore the message and blacklist the address
/// so that it won't be used in the future.
///
/// If the message is coming from a different node, the nodes address is added to the peer list
/// and its claimed addresses are associated with it.
///
/// If the `stage` of the message is 1, a `Message::Init` message with `stage=1` is sent in
/// reply, together with a peer list.
///
/// # `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> {
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) => {
let (src, _dst) = try!(P::parse(&payload[start..end]));
debug!("Writing data to device: {} bytes", end-start);
match self.device.write(&mut payload[..end], start) {
Ok(()) => (),
Err(e) => {
error!("Failed to send via device: {}", e);
return Err(Error::TunTapDev("Failed to write to device"));
}
}
if self.learning {
// Learn single address
self.table.learn(src, None, peer);
}
// Not adding peer in this case to increase performance
},
Message::Peers(peers) => {
// Connect to sender if not connected
if !self.peers.contains_addr(&peer) {
try!(self.connect(&peer));
}
// Connect to all peers in the message
for p in &peers {
if ! self.peers.contains_addr(p) && ! self.blacklist_peers.contains(p) {
try!(self.connect(p));
}
}
},
Message::Init(stage, node_id, ranges) => {
// Avoid connecting to self
if node_id == self.node_id {
self.blacklist_peers.push(peer);
return Ok(())
}
// Add sender as peer or as alternative address to existing peer
if self.peers.contains_node(&node_id) {
self.peers.add_alt_addr(node_id, peer);
} else {
self.peers.add(node_id, peer);
for range in ranges {
self.table.learn(range.base, Some(range.prefix_len), peer);
}
}
// Reply with stage=1 if stage is 0
if stage == 0 {
let peers = self.peers.as_vec();
let own_addrs = self.addresses.clone();
let own_node_id = self.node_id;
try!(self.send_msg(peer, &mut Message::Init(stage+1, own_node_id, own_addrs)));
try!(self.send_msg(peer, &mut Message::Peers(peers)));
}
},
Message::Close => {
self.peers.remove(&peer);
self.table.remove_all(&peer);
}
}
Ok(())
}
/// The main method of the node
///
/// This method will use epoll to wait in the sockets and the device at the same time.
/// It will read from the sockets, decode and decrypt the message and then call the
/// `handle_net_message` method. It will also read from the device and call
/// `handle_interface_data` for each packet read.
/// Also, this method will call `housekeep` every second.
#[allow(unknown_lints)]
#[allow(cyclomatic_complexity)]
pub fn run(&mut self) {
let dummy_time = Instant::now();
let trap = Trap::trap(&[SIGINT, SIGTERM, SIGQUIT]);
let mut poll_handle = try_fail!(Poll::new(3), "Failed to create poll handle: {}");
let socket4_fd = self.socket4.as_raw_fd();
let socket6_fd = self.socket6.as_raw_fd();
let device_fd = self.device.as_raw_fd();
try_fail!(poll_handle.register(socket4_fd, poll::READ), "Failed to add ipv4 socket to poll handle: {}");
try_fail!(poll_handle.register(socket6_fd, poll::READ), "Failed to add ipv4 socket to poll handle: {}");
try_fail!(poll_handle.register(device_fd, poll::READ), "Failed to add ipv4 socket to poll handle: {}");
let mut buffer = [0; 64*1024];
loop {
for evt in try_fail!(poll_handle.wait(1000), "Poll wait failed: {}") {
match evt.fd() {
fd if (fd == socket4_fd || fd == socket6_fd) => {
let (size, src) = match evt.fd() {
fd if fd == socket4_fd => try_fail!(self.socket4.recv_from(&mut buffer), "Failed to read from ipv4 network socket: {}"),
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)) {
error!("Error: {}, from: {}", e, src);
}
},
fd if (fd == device_fd) => {
let mut start = 64;
let (offset, size) = try_fail!(self.device.read(&mut buffer[start..]), "Failed to read from tap device: {}");
start += offset;
if let Err(e) = self.handle_interface_data(&mut buffer, start, start+size) {
error!("Error: {}", e);
}
},
_ => unreachable!()
}
}
if self.next_housekeep < now() {
// Check for signals
if trap.wait(dummy_time).is_some() {
break;
}
// Do the housekeeping
if let Err(e) = self.housekeep() {
error!("Error: {}", e)
}
self.next_housekeep = now() + 1
}
}
info!("Shutting down...");
self.broadcast_msg(&mut Message::Close).ok();
}
}