1 files changed, 268 insertions, 0 deletions
diff --git a/pkg/tcpip/timer_test.go b/pkg/tcpip/timer_test.go
new file mode 100644
index 000000000..a82384c49
--- /dev/null
+++ b/pkg/tcpip/timer_test.go
@@ -0,0 +1,268 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tcpip_test
+
+import (
+	"sync"
+	"testing"
+	"time"
+
+	"gvisor.dev/gvisor/pkg/tcpip"
+)
+
+const (
+	shortDuration  = 1 * time.Nanosecond
+	middleDuration = 100 * time.Millisecond
+	longDuration   = 1 * time.Second
+)
+
+func TestJobReschedule(t *testing.T) {
+	var clock tcpip.StdClock
+	var wg sync.WaitGroup
+	var lock sync.Mutex
+
+	for i := 0; i < 2; i++ {
+		wg.Add(1)
+
+		go func() {
+			lock.Lock()
+			// Assigning a new timer value updates the timer's locker and function.
+			// This test makes sure there is no data race when reassigning a timer
+			// that has an active timer (even if it has been stopped as a stopped
+			// timer may be blocked on a lock before it can check if it has been
+			// stopped while another goroutine holds the same lock).
+			job := tcpip.NewJob(&clock, &lock, func() {
+				wg.Done()
+			})
+			job.Schedule(shortDuration)
+			lock.Unlock()
+		}()
+	}
+	wg.Wait()
+}
+
+func TestJobExecution(t *testing.T) {
+	t.Parallel()
+
+	var clock tcpip.StdClock
+	var lock sync.Mutex
+	ch := make(chan struct{})
+
+	job := tcpip.NewJob(&clock, &lock, func() {
+		ch <- struct{}{}
+	})
+	job.Schedule(shortDuration)
+
+	// Wait for timer to fire.
+	select {
+	case <-ch:
+	case <-time.After(middleDuration):
+		t.Fatal("timed out waiting for timer to fire")
+	}
+
+	// The timer should have fired only once.
+	select {
+	case <-ch:
+		t.Fatal("no other timers should have fired")
+	case <-time.After(middleDuration):
+	}
+}
+
+func TestCancellableTimerResetFromLongDuration(t *testing.T) {
+	t.Parallel()
+
+	var clock tcpip.StdClock
+	var lock sync.Mutex
+	ch := make(chan struct{})
+
+	job := tcpip.NewJob(&clock, &lock, func() { ch <- struct{}{} })
+	job.Schedule(middleDuration)
+
+	lock.Lock()
+	job.Cancel()
+	lock.Unlock()
+
+	job.Schedule(shortDuration)
+
+	// Wait for timer to fire.
+	select {
+	case <-ch:
+	case <-time.After(middleDuration):
+		t.Fatal("timed out waiting for timer to fire")
+	}
+
+	// The timer should have fired only once.
+	select {
+	case <-ch:
+		t.Fatal("no other timers should have fired")
+	case <-time.After(middleDuration):
+	}
+}
+
+func TestJobRescheduleFromShortDuration(t *testing.T) {
+	t.Parallel()
+
+	var clock tcpip.StdClock
+	var lock sync.Mutex
+	ch := make(chan struct{})
+
+	lock.Lock()
+	job := tcpip.NewJob(&clock, &lock, func() { ch <- struct{}{} })
+	job.Schedule(shortDuration)
+	job.Cancel()
+	lock.Unlock()
+
+	// Wait for timer to fire if it wasn't correctly stopped.
+	select {
+	case <-ch:
+		t.Fatal("timer fired after being stopped")
+	case <-time.After(middleDuration):
+	}
+
+	job.Schedule(shortDuration)
+
+	// Wait for timer to fire.
+	select {
+	case <-ch:
+	case <-time.After(middleDuration):
+		t.Fatal("timed out waiting for timer to fire")
+	}
+
+	// The timer should have fired only once.
+	select {
+	case <-ch:
+		t.Fatal("no other timers should have fired")
+	case <-time.After(middleDuration):
+	}
+}
+
+func TestJobImmediatelyCancel(t *testing.T) {
+	t.Parallel()
+
+	var clock tcpip.StdClock
+	var lock sync.Mutex
+	ch := make(chan struct{})
+
+	for i := 0; i < 1000; i++ {
+		lock.Lock()
+		job := tcpip.NewJob(&clock, &lock, func() { ch <- struct{}{} })
+		job.Schedule(shortDuration)
+		job.Cancel()
+		lock.Unlock()
+	}
+
+	// Wait for timer to fire if it wasn't correctly stopped.
+	select {
+	case <-ch:
+		t.Fatal("timer fired after being stopped")
+	case <-time.After(middleDuration):
+	}
+}
+
+func TestJobCancelledRescheduleWithoutLock(t *testing.T) {
+	t.Parallel()
+
+	var clock tcpip.StdClock
+	var lock sync.Mutex
+	ch := make(chan struct{})
+
+	lock.Lock()
+	job := tcpip.NewJob(&clock, &lock, func() { ch <- struct{}{} })
+	job.Schedule(shortDuration)
+	job.Cancel()
+	lock.Unlock()
+
+	for i := 0; i < 10; i++ {
+		job.Schedule(middleDuration)
+
+		lock.Lock()
+		// Sleep until the timer fires and gets blocked trying to take the lock.
+		time.Sleep(middleDuration * 2)
+		job.Cancel()
+		lock.Unlock()
+	}
+
+	// Wait for double the duration so timers that weren't correctly stopped can
+	// fire.
+	select {
+	case <-ch:
+		t.Fatal("timer fired after being stopped")
+	case <-time.After(middleDuration * 2):
+	}
+}
+
+func TestManyCancellableTimerResetAfterBlockedOnLock(t *testing.T) {
+	t.Parallel()
+
+	var clock tcpip.StdClock
+	var lock sync.Mutex
+	ch := make(chan struct{})
+
+	lock.Lock()
+	job := tcpip.NewJob(&clock, &lock, func() { ch <- struct{}{} })
+	job.Schedule(shortDuration)
+	for i := 0; i < 10; i++ {
+		// Sleep until the timer fires and gets blocked trying to take the lock.
+		time.Sleep(middleDuration)
+		job.Cancel()
+		job.Schedule(shortDuration)
+	}
+	lock.Unlock()
+
+	// Wait for double the duration for the last timer to fire.
+	select {
+	case <-ch:
+	case <-time.After(middleDuration):
+		t.Fatal("timed out waiting for timer to fire")
+	}
+
+	// The timer should have fired only once.
+	select {
+	case <-ch:
+		t.Fatal("no other timers should have fired")
+	case <-time.After(middleDuration):
+	}
+}
+
+func TestManyJobReschedulesUnderLock(t *testing.T) {
+	t.Parallel()
+
+	var clock tcpip.StdClock
+	var lock sync.Mutex
+	ch := make(chan struct{})
+
+	lock.Lock()
+	job := tcpip.NewJob(&clock, &lock, func() { ch <- struct{}{} })
+	job.Schedule(shortDuration)
+	for i := 0; i < 10; i++ {
+		job.Cancel()
+		job.Schedule(shortDuration)
+	}
+	lock.Unlock()
+
+	// Wait for double the duration for the last timer to fire.
+	select {
+	case <-ch:
+	case <-time.After(middleDuration):
+		t.Fatal("timed out waiting for timer to fire")
+	}
+
+	// The timer should have fired only once.
+	select {
+	case <-ch:
+		t.Fatal("no other timers should have fired")
+	case <-time.After(middleDuration):
+	}
+}