tor_proto/channel.rs
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//! Code for talking directly (over a TLS connection) to a Tor client or relay.
//!
//! Channels form the basis of the rest of the Tor protocol: they are
//! the only way for two Tor instances to talk.
//!
//! Channels are not useful directly for application requests: after
//! making a channel, it needs to get used to build circuits, and the
//! circuits are used to anonymize streams. The streams are the
//! objects corresponding to directory requests.
//!
//! In general, you shouldn't try to manage channels on your own;
//! use the `tor-chanmgr` crate instead.
//!
//! To launch a channel:
//!
//! * Create a TLS connection as an object that implements AsyncRead +
//! AsyncWrite + StreamOps, and pass it to a [ChannelBuilder]. This will
//! yield an [handshake::OutboundClientHandshake] that represents
//! the state of the handshake.
//! * Call [handshake::OutboundClientHandshake::connect] on the result
//! to negotiate the rest of the handshake. This will verify
//! syntactic correctness of the handshake, but not its cryptographic
//! integrity.
//! * Call [handshake::UnverifiedChannel::check] on the result. This
//! finishes the cryptographic checks.
//! * Call [handshake::VerifiedChannel::finish] on the result. This
//! completes the handshake and produces an open channel and Reactor.
//! * Launch an asynchronous task to call the reactor's run() method.
//!
//! One you have a running channel, you can create circuits on it with
//! its [Channel::new_circ] method. See
//! [crate::circuit::PendingClientCirc] for information on how to
//! proceed from there.
//!
//! # Design
//!
//! For now, this code splits the channel into two pieces: a "Channel"
//! object that can be used by circuits to write cells onto the
//! channel, and a "Reactor" object that runs as a task in the
//! background, to read channel cells and pass them to circuits as
//! appropriate.
//!
//! I'm not at all sure that's the best way to do that, but it's what
//! I could think of.
//!
//! # Limitations
//!
//! This is client-only, and only supports link protocol version 4.
//!
//! TODO: There is no channel padding.
//!
//! TODO: There is no flow control, rate limiting, queueing, or
//! fairness.
/// The size of the channel buffer for communication between `Channel` and its reactor.
pub const CHANNEL_BUFFER_SIZE: usize = 128;
mod circmap;
mod codec;
mod handshake;
pub mod kist;
pub mod padding;
pub mod params;
mod reactor;
mod unique_id;
pub use crate::channel::params::*;
use crate::channel::reactor::{BoxedChannelSink, BoxedChannelStream, Reactor};
pub use crate::channel::unique_id::UniqId;
use crate::memquota::{ChannelAccount, CircuitAccount, SpecificAccount as _};
use crate::util::err::ChannelClosed;
use crate::util::oneshot_broadcast;
use crate::util::ts::AtomicOptTimestamp;
use crate::{circuit, ClockSkew};
use crate::{Error, Result};
use reactor::BoxedChannelStreamOps;
use safelog::sensitive as sv;
use std::future::{Future, IntoFuture};
use std::pin::Pin;
use std::sync::{Mutex, MutexGuard};
use std::time::Duration;
use tor_cell::chancell::msg::AnyChanMsg;
use tor_cell::chancell::{msg, msg::PaddingNegotiate, AnyChanCell, CircId};
use tor_cell::chancell::{ChanCell, ChanMsg};
use tor_cell::restricted_msg;
use tor_error::internal;
use tor_linkspec::{HasRelayIds, OwnedChanTarget};
use tor_memquota::mq_queue::{self, ChannelSpec as _, MpscSpec};
use tor_rtcompat::{CoarseTimeProvider, DynTimeProvider, SleepProvider, StreamOps};
/// Imports that are re-exported pub if feature `testing` is enabled
///
/// Putting them together in a little module like this allows us to select the
/// visibility for all of these things together.
mod testing_exports {
#![allow(unreachable_pub)]
pub use super::reactor::CtrlMsg;
pub use crate::circuit::celltypes::CreateResponse;
}
#[cfg(feature = "testing")]
pub use testing_exports::*;
#[cfg(not(feature = "testing"))]
use testing_exports::*;
use asynchronous_codec;
use futures::channel::mpsc;
use futures::io::{AsyncRead, AsyncWrite};
use oneshot_fused_workaround as oneshot;
use educe::Educe;
use futures::{FutureExt as _, Sink};
use std::result::Result as StdResult;
use std::sync::Arc;
use std::task::{Context, Poll};
use tracing::trace;
// reexport
use crate::channel::unique_id::CircUniqIdContext;
#[cfg(test)]
pub(crate) use codec::CodecError;
pub use handshake::{OutboundClientHandshake, UnverifiedChannel, VerifiedChannel};
use kist::KistParams;
restricted_msg! {
/// A channel message that we allow to be sent from a server to a client on
/// an open channel.
///
/// (An Open channel here is one on which we have received a NETINFO cell.)
///
/// Note that an unexpected message type will _not_ be ignored: instead, it
/// will cause the channel to shut down.
#[derive(Clone, Debug)]
pub(crate) enum OpenChanMsgS2C : ChanMsg {
Padding,
Vpadding,
// Not Create*, since we are not a relay.
// Not Created, since we never send CREATE.
CreatedFast,
Created2,
Relay,
// Not RelayEarly, since we are a client.
Destroy,
// Not PaddingNegotiate, since we are not a relay.
// Not Versions, Certs, AuthChallenge, Authenticate: they are for handshakes.
// Not Authorize: it is reserved, but unused.
}
}
/// A channel cell that we allot to be sent on an open channel from
/// a server to a client.
pub(crate) type OpenChanCellS2C = ChanCell<OpenChanMsgS2C>;
/// Type alias: A Sink and Stream that transforms a TLS connection into
/// a cell-based communication mechanism.
type CellFrame<T> =
asynchronous_codec::Framed<T, crate::channel::codec::ChannelCodec<OpenChanMsgS2C, AnyChanMsg>>;
/// An open client channel, ready to send and receive Tor cells.
///
/// A channel is a direct connection to a Tor relay, implemented using TLS.
///
/// This struct is a frontend that can be used to send cells
/// and otherwise control the channel. The main state is
/// in the Reactor object.
///
/// (Users need a mutable reference because of the types in `Sink`, and
/// ultimately because `cell_tx: mpsc::Sender` doesn't work without mut.
///
/// # Channel life cycle
///
/// Channels can be created directly here through the [`ChannelBuilder`] API.
/// For a higher-level API (with better support for TLS, pluggable transports,
/// and channel reuse) see the `tor-chanmgr` crate.
///
/// After a channel is created, it will persist until it is closed in one of
/// four ways:
/// 1. A remote error occurs.
/// 2. The other side of the channel closes the channel.
/// 3. Someone calls [`Channel::terminate`] on the channel.
/// 4. The last reference to the `Channel` is dropped. (Note that every circuit
/// on a `Channel` keeps a reference to it, which will in turn keep the
/// channel from closing until all those circuits have gone away.)
///
/// Note that in cases 1-3, the [`Channel`] object itself will still exist: it
/// will just be unusable for most purposes. Most operations on it will fail
/// with an error.
#[derive(Debug)]
pub struct Channel {
/// A channel used to send control messages to the Reactor.
control: mpsc::UnboundedSender<CtrlMsg>,
/// A channel used to send cells to the Reactor.
cell_tx: mq_queue::Sender<AnyChanCell, mq_queue::MpscSpec>,
/// A receiver that indicates whether the channel is closed.
///
/// Awaiting will return a `CancelledError` event when the reactor is dropped.
/// Read to decide if operations may succeed, and is returned by `wait_for_close`.
reactor_closed_rx: oneshot_broadcast::Receiver<Result<CloseInfo>>,
/// A unique identifier for this channel.
unique_id: UniqId,
/// Validated identity and address information for this peer.
peer_id: OwnedChanTarget,
/// The declared clock skew on this channel, at the time when this channel was
/// created.
clock_skew: ClockSkew,
/// The time when this channel was successfully completed
opened_at: coarsetime::Instant,
/// Mutable state used by the `Channel.
mutable: Mutex<MutableDetails>,
/// Information shared with the reactor
details: Arc<ChannelDetails>,
}
/// This is information shared between the reactor and the frontend (`Channel` object).
///
/// `control` can't be here because we rely on it getting dropped when the last user goes away.
#[derive(Debug)]
pub(crate) struct ChannelDetails {
/// Since when the channel became unused.
///
/// If calling `time_since_update` returns None,
/// this channel is still in use by at least one circuit.
///
/// Set by reactor when a circuit is added or removed.
/// Read from `Channel::duration_unused`.
unused_since: AtomicOptTimestamp,
/// Memory quota account
///
/// This is here partly because we need to ensure it lives as long as the channel,
/// as otherwise the memquota system will tear the account down.
#[allow(dead_code)]
memquota: ChannelAccount,
}
/// Mutable details (state) used by the `Channel` (frontend)
#[derive(Debug, Default)]
struct MutableDetails {
/// State used to control padding
padding: PaddingControlState,
}
/// State used to control padding
///
/// We store this here because:
///
/// 1. It must be per-channel, because it depends on channel usage. So it can't be in
/// (for example) `ChannelPaddingInstructionsUpdate`.
///
/// 2. It could be in the channel manager's per-channel state but (for code flow reasons
/// there, really) at the point at which the channel manager concludes for a pending
/// channel that it ought to update the usage, it has relinquished the lock on its own data
/// structure.
/// And there is actually no need for this to be global: a per-channel lock is better than
/// reacquiring the global one.
///
/// 3. It doesn't want to be in the channel reactor since that's super hot.
///
/// See also the overview at [`tor_proto::channel::padding`](padding)
#[derive(Debug, Educe)]
#[educe(Default)]
enum PaddingControlState {
/// No usage of this channel, so far, implies sending or negotiating channel padding.
///
/// This means we do not send (have not sent) any `ChannelPaddingInstructionsUpdates` to the reactor,
/// with the following consequences:
///
/// * We don't enable our own padding.
/// * We don't do any work to change the timeout distribution in the padding timer,
/// (which is fine since this timer is not enabled).
/// * We don't send any PADDING_NEGOTIATE cells. The peer is supposed to come to the
/// same conclusions as us, based on channel usage: it should also not send padding.
#[educe(Default)]
UsageDoesNotImplyPadding {
/// The last padding parameters (from reparameterize)
///
/// We keep this so that we can send it if and when
/// this channel starts to be used in a way that implies (possibly) sending padding.
padding_params: ChannelPaddingInstructionsUpdates,
},
/// Some usage of this channel implies possibly sending channel padding
///
/// The required padding timer, negotiation cell, etc.,
/// have been communicated to the reactor via a `CtrlMsg::ConfigUpdate`.
///
/// Once we have set this variant, it remains this way forever for this channel,
/// (the spec speaks of channels "only used for" certain purposes not getting padding).
PaddingConfigured,
}
use PaddingControlState as PCS;
/// A handle to a [`Channel`]` that can be used, by circuits, to send channel cells.
#[derive(Debug)]
pub(crate) struct ChannelSender {
/// MPSC sender to send cells.
cell_tx: mq_queue::Sender<AnyChanCell, mq_queue::MpscSpec>,
/// A receiver used to check if the channel is closed.
reactor_closed_rx: oneshot_broadcast::Receiver<Result<CloseInfo>>,
/// Unique ID for this channel. For logging.
unique_id: UniqId,
}
impl ChannelSender {
/// Check whether a cell type is permissible to be _sent_ on an
/// open client channel.
fn check_cell(&self, cell: &AnyChanCell) -> Result<()> {
use msg::AnyChanMsg::*;
let msg = cell.msg();
match msg {
Created(_) | Created2(_) | CreatedFast(_) => Err(Error::from(internal!(
"Can't send {} cell on client channel",
msg.cmd()
))),
Certs(_) | Versions(_) | Authenticate(_) | Authorize(_) | AuthChallenge(_)
| Netinfo(_) => Err(Error::from(internal!(
"Can't send {} cell after handshake is done",
msg.cmd()
))),
_ => Ok(()),
}
}
/// Obtain a reference to the `ChannelSender`'s [`DynTimeProvider`]
///
/// (This can sometimes be used to avoid having to keep
/// a separate clone of the time provider.)
pub(crate) fn time_provider(&self) -> &DynTimeProvider {
self.cell_tx.time_provider()
}
}
impl Sink<AnyChanCell> for ChannelSender {
type Error = Error;
fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> {
let this = self.get_mut();
Pin::new(&mut this.cell_tx)
.poll_ready(cx)
.map_err(|_| ChannelClosed.into())
}
fn start_send(self: Pin<&mut Self>, cell: AnyChanCell) -> Result<()> {
let this = self.get_mut();
if this.reactor_closed_rx.is_ready() {
return Err(ChannelClosed.into());
}
this.check_cell(&cell)?;
{
use msg::AnyChanMsg::*;
match cell.msg() {
Relay(_) | Padding(_) | Vpadding(_) => {} // too frequent to log.
_ => trace!(
"{}: Sending {} for {}",
this.unique_id,
cell.msg().cmd(),
CircId::get_or_zero(cell.circid())
),
}
}
Pin::new(&mut this.cell_tx)
.start_send(cell)
.map_err(|_| ChannelClosed.into())
}
fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> {
let this = self.get_mut();
Pin::new(&mut this.cell_tx)
.poll_flush(cx)
.map_err(|_| ChannelClosed.into())
}
fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> {
let this = self.get_mut();
Pin::new(&mut this.cell_tx)
.poll_close(cx)
.map_err(|_| ChannelClosed.into())
}
}
/// Structure for building and launching a Tor channel.
#[derive(Default)]
pub struct ChannelBuilder {
/// If present, a description of the address we're trying to connect to,
/// and the way in which we are trying to connect to it.
///
/// TODO: at some point, check this against the addresses in the netinfo
/// cell too.
target: Option<tor_linkspec::ChannelMethod>,
}
impl ChannelBuilder {
/// Construct a new ChannelBuilder.
pub fn new() -> Self {
ChannelBuilder::default()
}
/// Set the declared target method of this channel to correspond to a direct
/// connection to a given socket address.
#[deprecated(note = "use set_declared_method instead", since = "0.7.1")]
pub fn set_declared_addr(&mut self, target: std::net::SocketAddr) {
self.set_declared_method(tor_linkspec::ChannelMethod::Direct(vec![target]));
}
/// Set the declared target method of this channel.
///
/// Note that nothing enforces the correctness of this method: it
/// doesn't have to match the real method used to create the TLS
/// stream.
pub fn set_declared_method(&mut self, target: tor_linkspec::ChannelMethod) {
self.target = Some(target);
}
/// Launch a new client handshake over a TLS stream.
///
/// After calling this function, you'll need to call `connect()` on
/// the result to start the handshake. If that succeeds, you'll have
/// authentication info from the relay: call `check()` on the result
/// to check that. Finally, to finish the handshake, call `finish()`
/// on the result of _that_.
pub fn launch<T, S>(
self,
tls: T,
sleep_prov: S,
memquota: ChannelAccount,
) -> OutboundClientHandshake<T, S>
where
T: AsyncRead + AsyncWrite + StreamOps + Send + Unpin + 'static,
S: CoarseTimeProvider + SleepProvider,
{
handshake::OutboundClientHandshake::new(tls, self.target, sleep_prov, memquota)
}
}
impl Channel {
/// Construct a channel and reactor.
///
/// Internal method, called to finalize the channel when we've
/// sent our netinfo cell, received the peer's netinfo cell, and
/// we're finally ready to create circuits.
#[allow(clippy::too_many_arguments)] // TODO consider if we want a builder
fn new<S>(
link_protocol: u16,
sink: BoxedChannelSink,
stream: BoxedChannelStream,
streamops: BoxedChannelStreamOps,
unique_id: UniqId,
peer_id: OwnedChanTarget,
clock_skew: ClockSkew,
sleep_prov: S,
memquota: ChannelAccount,
) -> Result<(Arc<Self>, reactor::Reactor<S>)>
where
S: CoarseTimeProvider + SleepProvider,
{
use circmap::{CircIdRange, CircMap};
let circmap = CircMap::new(CircIdRange::High);
let dyn_time = DynTimeProvider::new(sleep_prov.clone());
let (control_tx, control_rx) = mpsc::unbounded();
let (cell_tx, cell_rx) = mq_queue::MpscSpec::new(CHANNEL_BUFFER_SIZE)
.new_mq(dyn_time.clone(), memquota.as_raw_account())?;
let unused_since = AtomicOptTimestamp::new();
unused_since.update();
let mutable = MutableDetails::default();
let (reactor_closed_tx, reactor_closed_rx) = oneshot_broadcast::channel();
let details = ChannelDetails {
unused_since,
memquota,
};
let details = Arc::new(details);
let channel = Arc::new(Channel {
control: control_tx,
cell_tx,
reactor_closed_rx,
unique_id,
peer_id,
clock_skew,
opened_at: coarsetime::Instant::now(),
mutable: Mutex::new(mutable),
details: Arc::clone(&details),
});
// We start disabled; the channel manager will `reconfigure` us soon after creation.
let padding_timer = Box::pin(padding::Timer::new_disabled(sleep_prov, None));
let reactor = Reactor {
control: control_rx,
cells: cell_rx,
reactor_closed_tx,
input: futures::StreamExt::fuse(stream),
output: sink,
streamops,
circs: circmap,
circ_unique_id_ctx: CircUniqIdContext::new(),
link_protocol,
unique_id,
details,
padding_timer,
special_outgoing: Default::default(),
};
Ok((channel, reactor))
}
/// Return a process-unique identifier for this channel.
pub fn unique_id(&self) -> UniqId {
self.unique_id
}
/// Return a reference to the memory tracking account for this Channel
pub fn mq_account(&self) -> &ChannelAccount {
&self.details.memquota
}
/// Obtain a reference to the `Channel`'s [`DynTimeProvider`]
///
/// (This can sometimes be used to avoid having to keep
/// a separate clone of the time provider.)
pub fn time_provider(&self) -> &DynTimeProvider {
self.cell_tx.time_provider()
}
/// Return an OwnedChanTarget representing the actual handshake used to
/// create this channel.
pub fn target(&self) -> &OwnedChanTarget {
&self.peer_id
}
/// Return the amount of time that has passed since this channel became open.
pub fn age(&self) -> Duration {
self.opened_at.elapsed().into()
}
/// Return a ClockSkew declaring how much clock skew the other side of this channel
/// claimed that we had when we negotiated the connection.
pub fn clock_skew(&self) -> ClockSkew {
self.clock_skew
}
/// Send a control message
fn send_control(&self, msg: CtrlMsg) -> StdResult<(), ChannelClosed> {
self.control
.unbounded_send(msg)
.map_err(|_| ChannelClosed)?;
Ok(())
}
/// Acquire the lock on `mutable` (and handle any poison error)
fn mutable(&self) -> MutexGuard<MutableDetails> {
self.mutable.lock().expect("channel details poisoned")
}
/// Specify that this channel should do activities related to channel padding
///
/// Initially, the channel does nothing related to channel padding:
/// it neither sends any padding, nor sends any PADDING_NEGOTIATE cells.
///
/// After this function has been called, it will do both,
/// according to the parameters specified through `reparameterize`.
/// Note that this might include *disabling* padding
/// (for example, by sending a `PADDING_NEGOTIATE`).
///
/// Idempotent.
///
/// There is no way to undo the effect of this call.
pub fn engage_padding_activities(&self) {
let mut mutable = self.mutable();
match &mutable.padding {
PCS::UsageDoesNotImplyPadding {
padding_params: params,
} => {
// Well, apparently the channel usage *does* imply padding now,
// so we need to (belatedly) enable the timer,
// send the padding negotiation cell, etc.
let mut params = params.clone();
// Except, maybe the padding we would be requesting is precisely default,
// so we wouldn't actually want to send that cell.
if params.padding_negotiate == Some(PaddingNegotiate::start_default()) {
params.padding_negotiate = None;
}
match self.send_control(CtrlMsg::ConfigUpdate(Arc::new(params))) {
Ok(()) => {}
Err(ChannelClosed) => return,
}
mutable.padding = PCS::PaddingConfigured;
}
PCS::PaddingConfigured => {
// OK, nothing to do
}
}
drop(mutable); // release the lock now: lock span covers the send, ensuring ordering
}
/// Reparameterise (update parameters; reconfigure)
///
/// Returns `Err` if the channel was closed earlier
pub fn reparameterize(&self, params: Arc<ChannelPaddingInstructionsUpdates>) -> Result<()> {
let mut mutable = self
.mutable
.lock()
.map_err(|_| internal!("channel details poisoned"))?;
match &mut mutable.padding {
PCS::PaddingConfigured => {
self.send_control(CtrlMsg::ConfigUpdate(params))?;
}
PCS::UsageDoesNotImplyPadding { padding_params } => {
padding_params.combine(¶ms);
}
}
drop(mutable); // release the lock now: lock span covers the send, ensuring ordering
Ok(())
}
/// Update the KIST parameters.
///
/// Returns `Err` if the channel is closed.
pub fn reparameterize_kist(&self, kist_params: KistParams) -> Result<()> {
Ok(self.send_control(CtrlMsg::KistConfigUpdate(kist_params))?)
}
/// Return an error if this channel is somehow mismatched with the
/// given target.
pub fn check_match<T: HasRelayIds + ?Sized>(&self, target: &T) -> Result<()> {
check_id_match_helper(&self.peer_id, target)
}
/// Return true if this channel is closed and therefore unusable.
pub fn is_closing(&self) -> bool {
self.reactor_closed_rx.is_ready()
}
/// If the channel is not in use, return the amount of time
/// it has had with no circuits.
///
/// Return `None` if the channel is currently in use.
pub fn duration_unused(&self) -> Option<std::time::Duration> {
self.details
.unused_since
.time_since_update()
.map(Into::into)
}
/// Return a new [`ChannelSender`] to transmit cells on this channel.
pub(crate) fn sender(&self) -> ChannelSender {
ChannelSender {
cell_tx: self.cell_tx.clone(),
reactor_closed_rx: self.reactor_closed_rx.clone(),
unique_id: self.unique_id,
}
}
/// Return a newly allocated PendingClientCirc object with
/// a corresponding circuit reactor. A circuit ID is allocated, but no
/// messages are sent, and no cryptography is done.
///
/// To use the results of this method, call Reactor::run() in a
/// new task, then use the methods of
/// [crate::circuit::PendingClientCirc] to build the circuit.
pub async fn new_circ(
self: &Arc<Self>,
) -> Result<(circuit::PendingClientCirc, circuit::reactor::Reactor)> {
if self.is_closing() {
return Err(ChannelClosed.into());
}
let time_prov = self.cell_tx.time_provider().clone();
let memquota = CircuitAccount::new(&self.details.memquota)?;
// TODO: blocking is risky, but so is unbounded.
let (sender, receiver) = MpscSpec::new(128).new_mq(time_prov, memquota.as_raw_account())?;
let (createdsender, createdreceiver) = oneshot::channel::<CreateResponse>();
let (tx, rx) = oneshot::channel();
self.send_control(CtrlMsg::AllocateCircuit {
created_sender: createdsender,
sender,
tx,
})?;
let (id, circ_unique_id) = rx.await.map_err(|_| ChannelClosed)??;
trace!("{}: Allocated CircId {}", circ_unique_id, id);
Ok(circuit::PendingClientCirc::new(
id,
self.clone(),
createdreceiver,
receiver,
circ_unique_id,
memquota,
))
}
/// Shut down this channel immediately, along with all circuits that
/// are using it.
///
/// Note that other references to this channel may exist. If they
/// do, they will stop working after you call this function.
///
/// It's not necessary to call this method if you're just done
/// with a channel: the channel should close on its own once nothing
/// is using it any more.
pub fn terminate(&self) {
let _ = self.send_control(CtrlMsg::Shutdown);
}
/// Tell the reactor that the circuit with the given ID has gone away.
pub fn close_circuit(&self, circid: CircId) -> Result<()> {
self.send_control(CtrlMsg::CloseCircuit(circid))?;
Ok(())
}
/// Return a future that will resolve once this channel has closed.
///
/// Note that this method does not _cause_ the channel to shut down on its own.
pub fn wait_for_close(
&self,
) -> impl Future<Output = StdResult<CloseInfo, ClosedUnexpectedly>> + Send + Sync + 'static
{
self.reactor_closed_rx
.clone()
.into_future()
.map(|recv| match recv {
Ok(Ok(info)) => Ok(info),
Ok(Err(e)) => Err(ClosedUnexpectedly::ReactorError(e)),
Err(oneshot_broadcast::SenderDropped) => Err(ClosedUnexpectedly::ReactorDropped),
})
}
/// Make a new fake reactor-less channel. For testing only, obviously.
///
/// Returns the receiver end of the control message mpsc.
///
/// Suitable for external callers who want to test behaviour
/// of layers including the logic in the channel frontend
/// (`Channel` object methods).
//
// This differs from test::fake_channel as follows:
// * It returns the mpsc Receiver
// * It does not require explicit specification of details
#[cfg(feature = "testing")]
pub fn new_fake() -> (Channel, mpsc::UnboundedReceiver<CtrlMsg>) {
let (control, control_recv) = mpsc::unbounded();
let details = fake_channel_details();
let unique_id = UniqId::new();
let peer_id = OwnedChanTarget::builder()
.ed_identity([6_u8; 32].into())
.rsa_identity([10_u8; 20].into())
.build()
.expect("Couldn't construct peer id");
// This will make rx trigger immediately.
let (_tx, rx) = oneshot_broadcast::channel();
let channel = Channel {
control,
cell_tx: fake_mpsc().0,
reactor_closed_rx: rx,
unique_id,
peer_id,
clock_skew: ClockSkew::None,
opened_at: coarsetime::Instant::now(),
mutable: Default::default(),
details,
};
(channel, control_recv)
}
}
/// If there is any identity in `wanted_ident` that is not present in
/// `my_ident`, return a ChanMismatch error.
///
/// This is a helper for [`Channel::check_match`] and
/// [`UnverifiedChannel::check_internal`].
fn check_id_match_helper<T, U>(my_ident: &T, wanted_ident: &U) -> Result<()>
where
T: HasRelayIds + ?Sized,
U: HasRelayIds + ?Sized,
{
for desired in wanted_ident.identities() {
let id_type = desired.id_type();
match my_ident.identity(id_type) {
Some(actual) if actual == desired => {}
Some(actual) => {
return Err(Error::ChanMismatch(format!(
"Identity {} does not match target {}",
sv(actual),
sv(desired)
)));
}
None => {
return Err(Error::ChanMismatch(format!(
"Peer does not have {} identity",
id_type
)))
}
}
}
Ok(())
}
impl HasRelayIds for Channel {
fn identity(
&self,
key_type: tor_linkspec::RelayIdType,
) -> Option<tor_linkspec::RelayIdRef<'_>> {
self.peer_id.identity(key_type)
}
}
/// The status of a channel which was closed successfully.
///
/// **Note:** This doesn't have any associated data,
/// but may be expanded in the future.
// I can't think of any info we'd want to return to waiters,
// but this type leaves the possibility open without requiring any backwards-incompatible changes.
#[derive(Clone, Debug)]
#[non_exhaustive]
pub struct CloseInfo;
/// The status of a channel which closed unexpectedly.
#[derive(Clone, Debug, thiserror::Error)]
#[non_exhaustive]
pub enum ClosedUnexpectedly {
/// The channel reactor was dropped or panicked before completing.
#[error("channel reactor was dropped or panicked before completing")]
ReactorDropped,
/// The channel reactor had an internal error.
#[error("channel reactor had an internal error")]
ReactorError(Error),
}
/// Make some fake channel details (for testing only!)
#[cfg(any(test, feature = "testing"))]
fn fake_channel_details() -> Arc<ChannelDetails> {
let unused_since = AtomicOptTimestamp::new();
Arc::new(ChannelDetails {
unused_since,
memquota: crate::util::fake_mq(),
})
}
/// Make an MPSC queue, of the type we use in Channels, but a fake one for testing
#[cfg(any(test, feature = "testing"))] // Used by Channel::new_fake which is also feature=testing
pub(crate) fn fake_mpsc() -> (
mq_queue::Sender<AnyChanCell, mq_queue::MpscSpec>,
mq_queue::Receiver<AnyChanCell, mq_queue::MpscSpec>,
) {
crate::fake_mpsc(CHANNEL_BUFFER_SIZE)
}
#[cfg(test)]
pub(crate) mod test {
// Most of this module is tested via tests that also check on the
// reactor code; there are just a few more cases to examine here.
#![allow(clippy::unwrap_used)]
use super::*;
use crate::channel::codec::test::MsgBuf;
pub(crate) use crate::channel::reactor::test::new_reactor;
use crate::util::fake_mq;
use tor_cell::chancell::msg::HandshakeType;
use tor_cell::chancell::{msg, AnyChanCell};
use tor_rtcompat::PreferredRuntime;
/// Make a new fake reactor-less channel. For testing only, obviously.
pub(crate) fn fake_channel(details: Arc<ChannelDetails>) -> Channel {
let unique_id = UniqId::new();
let peer_id = OwnedChanTarget::builder()
.ed_identity([6_u8; 32].into())
.rsa_identity([10_u8; 20].into())
.build()
.expect("Couldn't construct peer id");
// This will make rx trigger immediately.
let (_tx, rx) = oneshot_broadcast::channel();
Channel {
control: mpsc::unbounded().0,
cell_tx: fake_mpsc().0,
reactor_closed_rx: rx,
unique_id,
peer_id,
clock_skew: ClockSkew::None,
opened_at: coarsetime::Instant::now(),
mutable: Default::default(),
details,
}
}
#[test]
fn send_bad() {
tor_rtcompat::test_with_all_runtimes!(|_rt| async move {
use std::error::Error;
let chan = fake_channel(fake_channel_details());
let cell = AnyChanCell::new(CircId::new(7), msg::Created2::new(&b"hihi"[..]).into());
let e = chan.sender().check_cell(&cell);
assert!(e.is_err());
assert!(format!("{}", e.unwrap_err().source().unwrap())
.contains("Can't send CREATED2 cell on client channel"));
let cell = AnyChanCell::new(None, msg::Certs::new_empty().into());
let e = chan.sender().check_cell(&cell);
assert!(e.is_err());
assert!(format!("{}", e.unwrap_err().source().unwrap())
.contains("Can't send CERTS cell after handshake is done"));
let cell = AnyChanCell::new(
CircId::new(5),
msg::Create2::new(HandshakeType::NTOR, &b"abc"[..]).into(),
);
let e = chan.sender().check_cell(&cell);
assert!(e.is_ok());
// FIXME(eta): more difficult to test that sending works now that it has to go via reactor
// let got = output.next().await.unwrap();
// assert!(matches!(got.msg(), ChanMsg::Create2(_)));
});
}
#[test]
fn chanbuilder() {
let rt = PreferredRuntime::create().unwrap();
let mut builder = ChannelBuilder::default();
builder.set_declared_method(tor_linkspec::ChannelMethod::Direct(vec!["127.0.0.1:9001"
.parse()
.unwrap()]));
let tls = MsgBuf::new(&b""[..]);
let _outbound = builder.launch(tls, rt, fake_mq());
}
#[test]
fn check_match() {
let chan = fake_channel(fake_channel_details());
let t1 = OwnedChanTarget::builder()
.ed_identity([6; 32].into())
.rsa_identity([10; 20].into())
.build()
.unwrap();
let t2 = OwnedChanTarget::builder()
.ed_identity([1; 32].into())
.rsa_identity([3; 20].into())
.build()
.unwrap();
let t3 = OwnedChanTarget::builder()
.ed_identity([3; 32].into())
.rsa_identity([2; 20].into())
.build()
.unwrap();
assert!(chan.check_match(&t1).is_ok());
assert!(chan.check_match(&t2).is_err());
assert!(chan.check_match(&t3).is_err());
}
#[test]
fn unique_id() {
let ch1 = fake_channel(fake_channel_details());
let ch2 = fake_channel(fake_channel_details());
assert_ne!(ch1.unique_id(), ch2.unique_id());
}
#[test]
fn duration_unused_at() {
let details = fake_channel_details();
let ch = fake_channel(Arc::clone(&details));
details.unused_since.update();
assert!(ch.duration_unused().is_some());
}
}