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|
use super::device::DecryptionState;
use super::messages::TransportHeader;
use super::peer::Peer;
use super::pool::*;
use super::types::Callbacks;
use super::{tun, udp, Endpoint};
use ring::aead::{Aad, LessSafeKey, Nonce, UnboundKey, CHACHA20_POLY1305};
use zerocopy::{AsBytes, LayoutVerified};
use std::mem;
use std::sync::atomic::Ordering;
use std::sync::mpsc::Receiver;
use std::sync::Arc;
pub const SIZE_TAG: usize = 16;
pub struct Inbound<E: Endpoint, C: Callbacks, T: tun::Writer, B: udp::Writer<E>> {
msg: Vec<u8>,
failed: bool,
state: Arc<DecryptionState<E, C, T, B>>,
endpoint: Option<E>,
}
impl<E: Endpoint, C: Callbacks, T: tun::Writer, B: udp::Writer<E>> Inbound<E, C, T, B> {
pub fn new(
msg: Vec<u8>,
state: Arc<DecryptionState<E, C, T, B>>,
endpoint: E,
) -> Inbound<E, C, T, B> {
Inbound {
msg,
state,
failed: false,
endpoint: Some(endpoint),
}
}
}
#[inline(always)]
fn parallel<E: Endpoint, C: Callbacks, T: tun::Writer, B: udp::Writer<E>>(
peer: &Peer<E, C, T, B>,
body: &mut Inbound<E, C, T, B>,
) {
// cast to header followed by payload
let (header, packet): (LayoutVerified<&mut [u8], TransportHeader>, &mut [u8]) =
match LayoutVerified::new_from_prefix(&mut body.msg[..]) {
Some(v) => v,
None => {
log::debug!("inbound worker: failed to parse message");
return;
}
};
// authenticate and decrypt payload
{
// create 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);
// do the weird ring AEAD dance
let key = LessSafeKey::new(
UnboundKey::new(&CHACHA20_POLY1305, &body.state.keypair.recv.key[..]).unwrap(),
);
// attempt to open (and authenticate) the body
match key.open_in_place(nonce, Aad::empty(), packet) {
Ok(_) => (),
Err(_) => {
// fault and return early
body.failed = true;
return;
}
}
}
// cryptokey route and strip padding
let inner_len = {
let length = packet.len() - SIZE_TAG;
if length > 0 {
peer.device.table.check_route(&peer, &packet[..length])
} else {
Some(0)
}
};
// truncate to remove tag
match inner_len {
None => {
body.failed = true;
}
Some(len) => {
body.msg.truncate(mem::size_of::<TransportHeader>() + len);
}
}
}
#[inline(always)]
fn sequential<E: Endpoint, C: Callbacks, T: tun::Writer, B: udp::Writer<E>>(
peer: &Peer<E, C, T, B>,
body: &mut Inbound<E, C, T, B>,
) {
// decryption failed, return early
if body.failed {
return;
}
// cast transport header
let (header, packet): (LayoutVerified<&[u8], TransportHeader>, &[u8]) =
match LayoutVerified::new_from_prefix(&body.msg[..]) {
Some(v) => v,
None => {
log::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 !body.state.protector.lock().update(header.f_counter.get()) {
log::debug!("inbound worker: replay detected");
return;
}
// check for confirms key
if !body.state.confirmed.swap(true, Ordering::SeqCst) {
log::debug!("inbound worker: message confirms key");
peer.confirm_key(&body.state.keypair);
}
// update endpoint
*peer.endpoint.lock() = body.endpoint.take();
// calculate length of IP packet + padding
let length = packet.len() - SIZE_TAG;
log::debug!("inbound worker: plaintext length = {}", length);
// check if should be written to TUN
let mut sent = false;
if length > 0 {
sent = match peer.device.inbound.write(&packet[..]) {
Err(e) => {
log::debug!("failed to write inbound packet to TUN: {:?}", e);
false
}
Ok(_) => true,
}
} else {
log::debug!("inbound worker: received keepalive")
}
// trigger callback
C::recv(&peer.opaque, body.msg.len(), sent, &body.state.keypair);
}
#[inline(always)]
fn queue<E: Endpoint, C: Callbacks, T: tun::Writer, B: udp::Writer<E>>(
peer: &Peer<E, C, T, B>,
) -> &InorderQueue<Peer<E, C, T, B>, Inbound<E, C, T, B>> {
&peer.inbound
}
pub fn worker<E: Endpoint, C: Callbacks, T: tun::Writer, B: udp::Writer<E>>(
receiver: Receiver<Job<Peer<E, C, T, B>, Inbound<E, C, T, B>>>,
) {
worker_template(receiver, parallel, sequential, queue)
}
|
