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use std::mem;
use std::sync::mpsc::Receiver;
use std::sync::Arc;
use futures::sync::oneshot;
use futures::*;
use log::debug;
use ring::aead::{Aad, LessSafeKey, Nonce, UnboundKey, CHACHA20_POLY1305};
use std::net::{Ipv4Addr, Ipv6Addr};
use std::sync::atomic::Ordering;
use zerocopy::{AsBytes, LayoutVerified};
use super::device::{DecryptionState, DeviceInner};
use super::messages::{TransportHeader, TYPE_TRANSPORT};
use super::peer::PeerInner;
use super::types::Callbacks;
use super::super::types::{Endpoint, tun, bind};
use super::ip::*;
const SIZE_TAG: usize = 16;
#[derive(PartialEq, Debug)]
pub enum Operation {
Encryption,
Decryption,
}
pub struct JobBuffer {
pub msg: Vec<u8>, // message buffer (nonce and receiver id set)
pub key: [u8; 32], // chacha20poly1305 key
pub okay: bool, // state of the job
pub op: Operation, // should be buffer be encrypted / decrypted?
}
pub type JobParallel = (oneshot::Sender<JobBuffer>, JobBuffer);
#[allow(type_alias_bounds)]
pub type JobInbound<E, C, T, B: bind::Writer<E>> = (
Arc<DecryptionState<E, C, T, B>>,
E,
oneshot::Receiver<JobBuffer>,
);
pub type JobOutbound = oneshot::Receiver<JobBuffer>;
#[inline(always)]
fn check_route<E : Endpoint, C: Callbacks, T: tun::Writer, B: bind::Writer<E>>(
device: &Arc<DeviceInner<E, C, T, B>>,
peer: &Arc<PeerInner<E, C, T, B>>,
packet: &[u8],
) -> Option<usize> {
match packet[0] >> 4 {
VERSION_IP4 => {
// check length and cast to IPv4 header
let (header, _): (LayoutVerified<&[u8], IPv4Header>, _) =
LayoutVerified::new_from_prefix(packet)?;
// check IPv4 source address
device
.ipv4
.read()
.longest_match(Ipv4Addr::from(header.f_source))
.and_then(|(_, _, p)| {
if Arc::ptr_eq(p, &peer) {
Some(header.f_total_len.get() as usize)
} else {
None
}
})
}
VERSION_IP6 => {
// check length and cast to IPv6 header
let (header, _): (LayoutVerified<&[u8], IPv6Header>, _) =
LayoutVerified::new_from_prefix(packet)?;
// check IPv6 source address
device
.ipv6
.read()
.longest_match(Ipv6Addr::from(header.f_source))
.and_then(|(_, _, p)| {
if Arc::ptr_eq(p, &peer) {
Some(header.f_len.get() as usize + mem::size_of::<IPv6Header>())
} else {
None
}
})
}
_ => None,
}
}
pub fn worker_inbound<E : Endpoint, C: Callbacks, T: tun::Writer, B: bind::Writer<E>>(
device: Arc<DeviceInner<E, C, T, B>>, // related device
peer: Arc<PeerInner<E, C, T, B>>, // related peer
receiver: Receiver<JobInbound<E, C, T, B>>,
) {
loop {
// fetch job
let (state, endpoint, rx) = match receiver.recv() {
Ok(v) => v,
_ => {
return;
}
};
debug!("inbound worker: obtained job");
// wait for job to complete
let _ = rx
.map(|buf| {
debug!("inbound worker: job complete");
if buf.okay {
// cast transport header
let (header, packet): (LayoutVerified<&[u8], TransportHeader>, &[u8]) =
match LayoutVerified::new_from_prefix(&buf.msg[..]) {
Some(v) => v,
None => {
debug!("inbound worker: failed to parse message");
return;
}
};
debug_assert!(
packet.len() >= CHACHA20_POLY1305.tag_len(),
"this should be checked earlier in the pipeline (decryption should fail)"
);
// check for replay
if !state.protector.lock().update(header.f_counter.get()) {
debug!("inbound worker: replay detected");
return;
}
// check for confirms key
if !state.confirmed.swap(true, Ordering::SeqCst) {
debug!("inbound worker: message confirms key");
peer.confirm_key(&state.keypair);
}
// update endpoint
*peer.endpoint.lock() = Some(endpoint);
// calculate length of IP packet + padding
let length = packet.len() - SIZE_TAG;
debug!("inbound worker: plaintext length = {}", length);
// check if should be written to TUN
let mut sent = false;
if length > 0 {
if let Some(inner_len) = check_route(&device, &peer, &packet[..length]) {
debug_assert!(inner_len <= length, "should be validated");
if inner_len <= length {
sent = match device.inbound.write(&packet[..inner_len]) {
Err(e) => {
debug!("failed to write inbound packet to TUN: {:?}", e);
false
}
Ok(_) => true,
}
}
}
} else {
debug!("inbound worker: received keepalive")
}
// trigger callback
C::recv(&peer.opaque, buf.msg.len(), length == 0, sent);
} else {
debug!("inbound worker: authentication failure")
}
})
.wait();
}
}
pub fn worker_outbound<E : Endpoint, C: Callbacks, T: tun::Writer, B: bind::Writer<E>>(
device: Arc<DeviceInner<E, C, T, B>>, // related device
peer: Arc<PeerInner<E, C, T, B>>, // related peer
receiver: Receiver<JobOutbound>,
) {
loop {
// fetch job
let rx = match receiver.recv() {
Ok(v) => v,
_ => {
return;
}
};
debug!("outbound worker: obtained job");
// wait for job to complete
let _ = rx
.map(|buf| {
debug!("outbound worker: job complete");
if buf.okay {
// write to UDP bind
let xmit = if let Some(dst) = peer.endpoint.lock().as_ref() {
let send : &Option<B> = &*device.outbound.read();
if let Some(writer) = send.as_ref() {
match writer.write(&buf.msg[..], dst) {
Err(e) => {
debug!("failed to send outbound packet: {:?}", e);
false
}
Ok(_) => true,
}
} else {
false
}
} else {
false
};
// trigger callback
C::send(
&peer.opaque,
buf.msg.len(),
buf.msg.len() > SIZE_TAG + mem::size_of::<TransportHeader>(),
xmit,
);
}
})
.wait();
}
}
pub fn worker_parallel(receiver: Receiver<JobParallel>) {
loop {
// fetch next job
let (tx, mut buf) = match receiver.recv() {
Err(_) => {
return;
}
Ok(val) => val,
};
debug!("parallel worker: obtained job");
// make space for tag (TODO: consider moving this out)
if buf.op == Operation::Encryption {
buf.msg.extend([0u8; SIZE_TAG].iter());
}
// cast and check size of packet
let (mut header, packet): (LayoutVerified<&mut [u8], TransportHeader>, &mut [u8]) =
match LayoutVerified::new_from_prefix(&mut buf.msg[..]) {
Some(v) => v,
None => {
debug_assert!(
false,
"parallel worker: failed to parse message (insufficient size)"
);
continue;
}
};
debug_assert!(packet.len() >= CHACHA20_POLY1305.tag_len());
// do the weird ring AEAD dance
let key = LessSafeKey::new(UnboundKey::new(&CHACHA20_POLY1305, &buf.key[..]).unwrap());
// create a nonce object
let mut nonce = [0u8; 12];
debug_assert_eq!(nonce.len(), CHACHA20_POLY1305.nonce_len());
nonce[4..].copy_from_slice(header.f_counter.as_bytes());
let nonce = Nonce::assume_unique_for_key(nonce);
match buf.op {
Operation::Encryption => {
debug!("parallel worker: process encryption");
// set the type field
header.f_type.set(TYPE_TRANSPORT);
// encrypt content of transport message in-place
let end = packet.len() - SIZE_TAG;
let tag = key
.seal_in_place_separate_tag(nonce, Aad::empty(), &mut packet[..end])
.unwrap();
// append tag
packet[end..].copy_from_slice(tag.as_ref());
buf.okay = true;
}
Operation::Decryption => {
debug!("parallel worker: process decryption");
// opening failure is signaled by fault state
buf.okay = match key.open_in_place(nonce, Aad::empty(), packet) {
Ok(_) => true,
Err(_) => false,
};
}
}
// pass ownership to consumer
let okay = tx.send(buf);
debug!(
"parallel worker: passing ownership to sequential worker: {}",
okay.is_ok()
);
}
}
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