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|
//! This module has been reimplemented multiple times, often to no avail, with main issues being
//! that the app gets stuck in an offline state, blocking all internet access and preventing the
//! user from connecting to a relay.
//!
//! See [RouteManagerHandle::default_route_listener].
//!
//! This offline monitor synthesizes an offline state between network switches and before coming
//! online from an offline state. This is done to work around issues with DNS being blocked due
//! to macOS's connectivity check. In the offline state, a DNS server on localhost prevents the
//! connectivity check from being blocked.
use futures::{
StreamExt,
channel::mpsc::UnboundedSender,
future::{Fuse, FutureExt},
select,
};
use std::{
sync::{Arc, Mutex},
time::Duration,
};
use talpid_routing::{DefaultRouteEvent, RouteManagerHandle};
use talpid_types::net::Connectivity;
const SYNTHETIC_OFFLINE_DURATION: Duration = Duration::from_secs(1);
#[derive(thiserror::Error, Debug)]
pub enum Error {
#[error("Failed to initialize route monitor")]
StartMonitorError(#[from] talpid_routing::Error),
}
pub struct MonitorHandle {
state: Arc<Mutex<ConnectivityInner>>,
_notify_tx: Arc<UnboundedSender<Connectivity>>,
}
impl MonitorHandle {
/// Return whether the host is offline
#[allow(clippy::unused_async)]
pub async fn connectivity(&self) -> Connectivity {
let state = self.state.lock().unwrap();
state.into_connectivity()
}
}
#[derive(Clone, Copy, Debug, PartialEq)]
struct ConnectivityInner {
/// Whether IPv4 connectivity seems to be available on the host.
ipv4: bool,
/// Whether IPv6 connectivity seems to be available on the host.
ipv6: bool,
}
impl ConnectivityInner {
fn into_connectivity(self) -> Connectivity {
Connectivity::new(self.ipv4, self.ipv6)
}
fn is_online(&self) -> bool {
self.into_connectivity().is_online()
}
}
pub async fn spawn_monitor(
notify_tx: UnboundedSender<Connectivity>,
route_manager: RouteManagerHandle,
) -> Result<MonitorHandle, Error> {
let notify_tx = Arc::new(notify_tx);
// note: begin observing before initializing the state
let route_listener = route_manager.default_route_listener().await?;
let (ipv4, ipv6) = match route_manager.get_default_routes().await {
Ok((v4_route, v6_route)) => (v4_route.is_some(), v6_route.is_some()),
Err(error) => {
log::warn!("Failed to initialize offline monitor: {error}");
// Fail open: Assume that we have connectivity if we cannot determine the existence of
// a default route, since we don't want to block the user from connecting
(true, true)
}
};
let state = ConnectivityInner { ipv4, ipv6 };
let mut real_state = state;
let state = Arc::new(Mutex::new(state));
let weak_state = Arc::downgrade(&state);
let weak_notify_tx = Arc::downgrade(¬ify_tx);
// Detect changes to the default route
tokio::spawn(async move {
let mut timeout = Fuse::terminated();
let mut route_listener = route_listener.fuse();
loop {
talpid_types::detect_flood!();
select! {
_ = timeout => {
// Update shared state
let Some(state) = weak_state.upgrade() else {
break;
};
let mut state = state.lock().unwrap();
if real_state.is_online() {
log::info!("Connectivity changed: Connected");
let Some(tx) = weak_notify_tx.upgrade() else {
break;
};
let _ = tx.unbounded_send(real_state.into_connectivity());
}
*state = real_state;
}
route_event = route_listener.next() => {
let Some(event) = route_event else {
break;
};
// Update real state
match event {
DefaultRouteEvent::AddedOrChangedV4 => {
real_state.ipv4 = true;
}
DefaultRouteEvent::AddedOrChangedV6 => {
real_state.ipv6 = true;
}
DefaultRouteEvent::RemovedV4 => {
real_state.ipv4 = false;
}
DefaultRouteEvent::RemovedV6 => {
real_state.ipv6 = false;
}
}
// Synthesize offline state
// Update shared state
let Some(state) = weak_state.upgrade() else {
break;
};
let mut state = state.lock().unwrap();
let previous_connectivity = *state;
state.ipv4 = false;
state.ipv6 = false;
if previous_connectivity.is_online() {
let Some(tx) = weak_notify_tx.upgrade() else {
break;
};
let _ = tx.unbounded_send(state.into_connectivity());
log::info!("Connectivity changed: Offline");
}
if real_state.is_online() {
timeout = Box::pin(tokio::time::sleep(SYNTHETIC_OFFLINE_DURATION)).fuse();
}
}
}
}
log::trace!("Offline monitor exiting");
});
Ok(MonitorHandle {
state,
_notify_tx: notify_tx,
})
}
|
