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// Copyright 2017 Sopium
// This file is part of WireGuard.rs.
// WireGuard.rs is free software: you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
// WireGuard.rs is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with WireGuard.rs. If not, see <https://www.gnu.org/licenses/>.
use std::collections::HashSet;
use std::hash::{Hash, Hasher};
use std::ops::Deref;
use std::sync::{Arc, Mutex};
use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
use std::thread;
use std::time::{Duration, Instant};
type Action = Box<Fn() + Send + Sync>;
struct Timer {
activated: AtomicBool,
// Actually, this is not used outside the big whole wheel mutex.
// But how to tell the compiler that???
rounds: AtomicUsize,
action: Action,
}
pub struct TimerHandle {
controller: Arc<Mutex<Wheel>>,
pos: AtomicUsize,
timer: ArcTimer,
}
// A single round will be ~ 16 seconds.
// WireGuard timers are mostly in this range.
const WHEEL_SLOTS: usize = 128;
const TICK_MS: usize = 128;
// This is hashed timing wheel.
pub struct TimerController(Arc<Mutex<Wheel>>);
struct Wheel {
// Usually a linked list is used in each slot.
// Use hash table for now, for implementation simplicity.
// It's slower but should still have same complexity.
wheel: Vec<HashSet<ArcTimer>>,
cur: usize,
}
impl TimerController {
pub fn new() -> Self {
let con = Arc::new(Mutex::new(Wheel {
wheel: ::std::iter::repeat(HashSet::new()).take(WHEEL_SLOTS).collect(),
cur: 0,
}));
let con1 = con.clone();
thread::Builder::new().name("timer".to_string()).spawn(move || {
loop {
let tick_start = Instant::now();
let mut to_run = Vec::new();
let mut wheel = con.lock().unwrap();
let cur = wheel.cur;
wheel.cur = (wheel.cur + 1) % WHEEL_SLOTS;
{
let slot = &mut wheel.wheel[cur];
slot.retain(|t| {
Arc::strong_count(&t.0) > 1
});
for t in slot.iter() {
// `fetch_sub` always wraps, doesn't it?
let rounds = t.rounds.fetch_sub(1, Ordering::Relaxed);
if t.activated.load(Ordering::Relaxed) && rounds == 0 {
to_run.push(t.clone());
t.activated.store(false, Ordering::Relaxed);
}
}
}
drop(wheel);
for t in to_run {
(t.action)();
}
let spent = tick_start.elapsed();
#[allow(non_snake_case)]
let TICK = Duration::from_millis(TICK_MS as u64);
if spent >= TICK {
warn!("timer tick processing time exceeds TICK!");
} else {
thread::sleep(TICK - spent);
}
}
}).unwrap();
TimerController(con1)
}
pub fn register_delay(&self, delay: Duration, action: Action) -> TimerHandle {
let (offset, rounds) = calc_offset_and_rounds(delay);
let mut wheel = self.0.lock().unwrap();
let pos = (wheel.cur + offset) % WHEEL_SLOTS;
let timer = Arc::new(Timer {
activated: AtomicBool::new(false),
rounds: AtomicUsize::new(rounds),
action: action,
});
wheel.wheel[pos].insert(ArcTimer(timer.clone()));
TimerHandle {
controller: self.0.clone(),
pos: AtomicUsize::new(pos),
timer: ArcTimer(timer),
}
}
}
impl TimerHandle {
pub fn activate(&self) {
self.timer.activated.store(true, Ordering::Relaxed);
}
pub fn de_activate(&self) {
self.timer.activated.store(false, Ordering::Relaxed);
}
pub fn adjust_and_activate(&self, secs: u64) {
let (offset, rounds) = calc_offset_and_rounds(Duration::from_secs(secs));
let mut wheel = self.controller.lock().unwrap();
let old_pos = self.pos.load(Ordering::Relaxed);
let new_pos = (wheel.cur + offset) % WHEEL_SLOTS;
self.pos.store(new_pos, Ordering::Relaxed);
self.timer.rounds.store(rounds, Ordering::Relaxed);
let t = wheel.wheel[old_pos].take(&self.timer).unwrap();
wheel.wheel[new_pos].insert(t);
self.timer.activated.store(true, Ordering::Release);
}
pub fn adjust_and_activate_if_not_activated(&self, secs: u64) {
if !self.timer.activated.load(Ordering::Relaxed) {
self.adjust_and_activate(secs);
}
}
}
fn calc_offset_and_rounds(delay: Duration) -> (usize, usize) {
let delay_ms = delay.as_secs() * 1000 + delay.subsec_nanos() as u64 / 1000000;
let ticks = ::std::cmp::max(delay_ms as usize / TICK_MS, 1);
let offset = ticks % WHEEL_SLOTS;
let rounds = ticks / WHEEL_SLOTS;
(offset, rounds)
}
/// Hash and Eq by pointer address.
#[derive(Clone)]
struct ArcTimer(Arc<Timer>);
impl Deref for ArcTimer {
type Target = Timer;
fn deref(&self) -> &Timer {
self.0.deref()
}
}
impl Hash for ArcTimer {
fn hash<H: Hasher>(&self, state: &mut H) {
(self.0.deref() as *const Timer).hash(state);
}
}
impl PartialEq for ArcTimer {
fn eq(&self, other: &ArcTimer) -> bool {
Arc::ptr_eq(&self.0, &other.0)
}
}
impl Eq for ArcTimer {
}
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