Lines
48.57 %
Functions
16.13 %
Branches
100 %
//! Traits and code to define different mechanisms for building Channels to
//! different kinds of targets.
use std::sync::{Arc, Mutex};
use crate::event::ChanMgrEventSender;
use async_trait::async_trait;
use tor_error::{HasKind, HasRetryTime, internal};
use tor_linkspec::{HasChanMethod, OwnedChanTarget, PtTransportName};
use tor_proto::channel::Channel;
use tor_proto::memquota::ChannelAccount;
use tracing::{debug, instrument};
#[cfg(feature = "relay")]
use safelog::Sensitive;
/// An opaque type that lets a `ChannelFactory` update the `ChanMgr` about bootstrap progress.
///
/// A future release of this crate might make this type less opaque.
// FIXME(eta): Do that.
#[derive(Clone)]
pub struct BootstrapReporter(pub(crate) Arc<Mutex<ChanMgrEventSender>>);
impl BootstrapReporter {
#[cfg(test)]
/// Create a useless version of this type to satisfy some test.
pub(crate) fn fake() -> Self {
let (snd, _rcv) = crate::event::channel();
Self(Arc::new(Mutex::new(snd)))
}
/// An object that knows how to build `Channels` to `ChanTarget`s.
/// This trait must be object-safe.
/// Every [`ChanMgr`](crate::ChanMgr) has a `ChannelFactory` that it uses to
/// construct all of its channels.
/// A `ChannelFactory` can be implemented in terms of a
/// [`TransportImplHelper`](crate::transport::TransportImplHelper), by wrapping it in a
/// `ChanBuilder`.
// FIXME(eta): Rectify the below situation.
/// (In fact, as of the time of writing, this is the *only* way to implement this trait
/// outside of this crate while keeping bootstrap status reporting, since `BootstrapReporter`
/// is an opaque type.)
#[async_trait]
pub trait ChannelFactory: Send + Sync {
/// Open an authenticated channel to `target`.
/// This method does does not necessarily handle retries or timeouts,
/// although some of its implementations may.
/// This method does not necessarily handle every kind of transport. If the
/// caller provides a target with an unsupported
/// [`TransportId`](tor_linkspec::TransportId), this method should return
/// [`Error::NoSuchTransport`](crate::Error::NoSuchTransport).
async fn connect_via_transport(
&self,
target: &OwnedChanTarget,
reporter: BootstrapReporter,
memquota: ChannelAccount,
) -> crate::Result<Arc<Channel>>;
/// Similar to [`ChannelFactory`], but for building channels from incoming streams.
// This is a separate trait since for some `ChannelFactory`s like the one returned from
// `tor_ptmgr::PtMgr::factory_for_transport`, it doesn't make sense to deal with incoming streams
// (all PT connections are outgoing).
pub trait IncomingChannelFactory: Send + Sync {
/// The type of byte stream that's required to build channels for incoming connections.
type Stream: Send + Sync + 'static;
/// Open a channel from `peer` with the given `stream`. The channel may or may not be
/// authenticated.
async fn accept_from_transport(
peer: Sensitive<std::net::SocketAddr>,
stream: Self::Stream,
impl<CF> crate::mgr::AbstractChannelFactory for CF
where
CF: ChannelFactory + IncomingChannelFactory + Sync,
{
type Channel = tor_proto::channel::Channel;
type BuildSpec = OwnedChanTarget;
type Stream = CF::Stream;
#[instrument(skip_all, level = "trace")]
async fn build_channel(
target: &Self::BuildSpec,
) -> crate::Result<Arc<Self::Channel>> {
debug!("Attempting to open a new channel to {target}");
self.connect_via_transport(target, reporter, memquota).await
async fn build_channel_using_incoming(
) -> crate::Result<Arc<tor_proto::channel::Channel>> {
debug!("Attempting to open a new channel from {peer}");
self.accept_from_transport(peer, stream, memquota).await
/// The error type returned by a pluggable transport manager.
pub trait AbstractPtError:
std::error::Error + HasKind + HasRetryTime + Send + Sync + std::fmt::Debug
/// A pluggable transport manager.
/// We can't directly reference the `PtMgr` type from `tor-ptmgr`, because of dependency resolution
/// constraints, so this defines the interface for what one should look like.
pub trait AbstractPtMgr: Send + Sync {
/// Get a `ChannelFactory` for the provided `PtTransportName`.
async fn factory_for_transport(
transport: &PtTransportName,
) -> Result<Option<Arc<dyn ChannelFactory + Send + Sync>>, Arc<dyn AbstractPtError>>;
impl<P> AbstractPtMgr for Option<P>
P: AbstractPtMgr,
) -> Result<Option<Arc<dyn ChannelFactory + Send + Sync>>, Arc<dyn AbstractPtError>> {
match self {
Some(mgr) => mgr.factory_for_transport(transport).await,
None => Ok(None),
/// A ChannelFactory built from an optional PtMgr to use for pluggable transports, and a
/// ChannelFactory to use for everything else.
pub(crate) struct CompoundFactory<CF> {
#[cfg(feature = "pt-client")]
/// The PtMgr to use for pluggable transports
ptmgr: Option<Arc<dyn AbstractPtMgr + 'static>>,
/// The factory to use for everything else
default_factory: Arc<CF>,
impl<CF> Clone for CompoundFactory<CF> {
fn clone(&self) -> Self {
Self {
ptmgr: self.ptmgr.as_ref().map(Arc::clone),
default_factory: Arc::clone(&self.default_factory),
impl<CF: ChannelFactory> ChannelFactory for CompoundFactory<CF> {
) -> crate::Result<Arc<Channel>> {
use tor_linkspec::ChannelMethod::*;
let factory = match target.chan_method() {
Direct(_) => self.default_factory.clone(),
Pluggable(a) => match self.ptmgr.as_ref() {
Some(mgr) => mgr
.factory_for_transport(a.transport())
.await
.map_err(crate::Error::Pt)?
.ok_or_else(|| crate::Error::NoSuchTransport(a.transport().clone().into()))?,
None => return Err(crate::Error::NoSuchTransport(a.transport().clone().into())),
},
#[allow(unreachable_patterns)]
_ => {
return Err(crate::Error::Internal(internal!(
"No support for channel method"
)));
};
factory
.connect_via_transport(target, reporter, memquota)
impl<CF: IncomingChannelFactory> IncomingChannelFactory for CompoundFactory<CF> {
self.default_factory
.accept_from_transport(peer, stream, memquota)
impl<CF: ChannelFactory + 'static> CompoundFactory<CF> {
/// Create a new `Factory` that will try to use `ptmgr` to handle pluggable
/// transports requests, and `default_factory` to handle everything else.
pub(crate) fn new(
#[cfg(feature = "pt-client")] ptmgr: Option<Arc<dyn AbstractPtMgr + 'static>>,
) -> Self {
default_factory,
ptmgr,
/// Replace the PtMgr in this object.
pub(crate) fn replace_ptmgr(&mut self, ptmgr: Arc<dyn AbstractPtMgr + 'static>) {
self.ptmgr = Some(ptmgr);
/// Return a reference to the default channel factory.
pub(crate) fn default_factory(&self) -> &CF {
&self.default_factory
/// Replace the default channel factory.
pub(crate) fn replace_default_factory(&mut self, factory: Arc<CF>) {
self.default_factory = factory;