erpc_scanner/client.rs
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use crate::{
relay::{NetDirProvider, NetDirProviderEvent, RelaysPool},
utils::CombinedUnboundedChannel,
work::{CompletedWork, CompletedWorkStatus, IncompleteWork},
};
use crossbeam::atomic::AtomicCell;
use futures::stream::StreamExt;
use std::{cmp::Ordering, sync::Arc};
use tokio::sync::{
mpsc::{self, UnboundedSender},
Mutex,
};
use tokio_stream::wrappers::UnboundedReceiverStream;
use tor_chanmgr::ChannelUsage;
use tor_circmgr::{
build::exit_circparams_from_netparams, path::TorPath, CircMgr,
};
use tor_netdir::{NetDir, Relay};
use tor_rtcompat::Runtime;
pub(crate) struct Client<R: Runtime> {
// CircMgr used to build circuits
circmgr: Arc<CircMgr<R>>,
// The [NetDirProvider] to get the latest NetDir
netdir_provider: Arc<NetDirProvider>,
// Channel for getting the IncompleteWork from the pool
incomplete_work_channel: Arc<CombinedUnboundedChannel<IncompleteWork>>,
/// The stream to access the result of completed work given out by this [Client]
output_stream: Mutex<UnboundedReceiverStream<CompletedWork>>,
/// The current no of work left in the channel
current_load: AtomicCell<u16>,
}
impl<R: Runtime> Client<R> {
/// Creates a new `WorkerTorClient` instance with the provided `tor_client`.
pub(crate) async fn new(
circmgr: Arc<CircMgr<R>>,
netdir_provider: Arc<NetDirProvider>,
netdir: Arc<NetDir>,
) -> anyhow::Result<Arc<Self>> {
// Channel for transferring the CompletedWork from client to the pool
let (sd, rv) = mpsc::unbounded_channel();
let client = Arc::new(Self {
circmgr,
netdir_provider,
incomplete_work_channel: Arc::new(CombinedUnboundedChannel::<
IncompleteWork,
>::new()),
output_stream: Mutex::new(UnboundedReceiverStream::new(rv)),
current_load: AtomicCell::<u16>::new(0),
});
client.start_work(sd, netdir);
Ok(client)
}
/// Pushes the [IncompleteWork] into the incomplete_work_channel
pub(crate) fn push_incomplete_work(
&self,
work: &IncompleteWork,
) -> anyhow::Result<()> {
self.incomplete_work_channel.sender.send(work.clone())?;
// Increase the load counter by 1
self.current_load.store(self.current_load.load() + 1);
Ok(())
}
/// Receiving half for the CompletedWork
pub(crate) async fn recv_completed_work(&self) -> Option<CompletedWork> {
let mut output_stream = self.output_stream.lock().await;
match output_stream.next().await {
Some(completed_work) => {
let current_load = self.current_load.load();
if current_load > 0 {
self.current_load.store(self.current_load.load() - 1);
}
Some(completed_work)
}
None => None,
}
}
/// Starts the work on the WorkerTorClient as a tokio task, the spawned "task",
/// it listens for IncompleteWork in the ```self.incomplete_work_channel``` half
/// and then performs the work and gives back the completed work to the internal
/// channel of the WorkerTorClient through UnboundedSender<CompletedWork> ```self.output_stream```
/// can be used to dequeue the incomplete work
fn start_work(
&self,
sd: UnboundedSender<CompletedWork>,
netdir: Arc<NetDir>,
) {
let circmgr = self.circmgr.clone();
let netdir_provider = self.netdir_provider.clone();
// The channel where we will get IncompleteWork to work on
let incomplete_work_channel = self.incomplete_work_channel.clone();
tokio::spawn(async move {
let mut current_netdir = netdir;
let mut relays_pool = {
let relays: Vec<(Relay<'_>, ())> =
current_netdir.relays().map(|relay| (relay, ())).collect();
RelaysPool::from_relays(&relays)
};
let mut incomplete_work_receiver_guard =
incomplete_work_channel.receiver.lock().await;
let completed_work_sender = sd;
let mut netdir_provider_event_receiver =
netdir_provider.get_netdirprodiver_event_receiver();
// Start receiving IncompleteWork provided by the pool
while let Some(incomplete_work) =
incomplete_work_receiver_guard.recv().await
{
// If there's a new NetDirProviderEvent, this loop prevents the IncompleteWork being lost,
// this loop will run until there's an Error on receiving and is broken after
// hadning over the work to one of the client
'work_loss_prevention: loop {
// Check if a new NetDirProviderEvent has arrived
match netdir_provider_event_receiver.try_recv() {
// If there's a new NetDir we update the NetDir and the RelaysPool
Ok(netdirprovider_event) => match netdirprovider_event
{
NetDirProviderEvent::NetDirChanged(netdir) => {
current_netdir = netdir;
relays_pool = {
let relays: Vec<(Relay<'_>, ())> =
current_netdir
.relays()
.map(|relay| (relay, ()))
.collect();
RelaysPool::from_relays(&relays)
};
}
},
Err(_) => {
let source_relay = {
relays_pool
.get_relay(&incomplete_work.source_relay)
};
let destination_relay = {
relays_pool.get_relay(
&incomplete_work.destination_relay,
)
};
// The relays between whom we were requested for a circuit to be created in
// the IncompleteWork, we should check if they even exist in the current FRESH NetDir by
// looking at the current RelaysPool
//
// If either source or destination relay is not present, THEN (TODO)(Figure
// out a solution)
let timestamp =
chrono::Utc::now().timestamp() as u64;
let completed_work = if let (
Some(source_relay),
Some(destination_relay),
) =
(source_relay, destination_relay)
{
let source_relay = source_relay.clone();
let destination_relay =
destination_relay.clone();
let two_hop_path = TorPath::new_multihop([
source_relay.0.clone(),
destination_relay.0.clone(),
]);
let net_params = current_netdir.params();
let circ_params =
exit_circparams_from_netparams(net_params)
.unwrap();
let circ_usage = ChannelUsage::UselessCircuit;
let completed_work_status = match circmgr
.builder()
.build(
&two_hop_path,
&circ_params,
circ_usage,
)
.await
{
Ok(circ) => {
// Async order to shut down the circuit
circ.terminate();
CompletedWorkStatus::Success
}
Err(err) => CompletedWorkStatus::Failure(
err.to_string(),
),
};
CompletedWork {
source_relay: incomplete_work.source_relay,
destination_relay: incomplete_work
.destination_relay,
timestamp,
status: completed_work_status,
}
} else {
let failure = {
let source_relay_presence =
if source_relay.is_none() {
"not present"
} else {
"present"
};
let destination_relay_presence =
if destination_relay.is_none() {
"not present"
} else {
"present"
};
// TODO: Specify someway to index the NetDir, either give info
// about md consensus that NetDir was built from or the lifetime of
// the NetDir
format!(
"The source relay was {} and destination relay was {} in the NetDir",
source_relay_presence, destination_relay_presence
)
};
CompletedWork {
source_relay: incomplete_work.source_relay,
destination_relay: incomplete_work
.destination_relay,
timestamp,
status: CompletedWorkStatus::Failure(
failure,
),
}
};
completed_work_sender
.send(completed_work)
.unwrap();
break 'work_loss_prevention;
}
}
}
}
});
}
}
/// The implementation of PartialEq only compares the load value of the WorkerTorClient, which
/// means two [Client]s are the same if they have the same no of load, they are same in a
/// sense that they carry equal no of work to perform
impl<R: Runtime> PartialEq for Client<R> {
fn eq(&self, other: &Self) -> bool {
let current_load_left = self.current_load.load();
let current_load_right = other.current_load.load();
current_load_left == current_load_right
}
}
impl<R: Runtime> Eq for Client<R> {}
// The implementation of PartialOrd also only compares the load value of the Client
impl<R: Runtime> PartialOrd for Client<R> {
fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
Some(self.cmp(other))
}
}
impl<R: Runtime> Ord for Client<R> {
fn cmp(&self, other: &Self) -> Ordering {
let current_load_left = self.current_load.load();
let current_load_right = other.current_load.load();
current_load_left.cmp(¤t_load_right)
}
}