Cleanup tcp.timer and tcpip.Route

When a tcp.timer or tcpip.Route is no longer used, clean up its
resources so that unused memory may be released.

PiperOrigin-RevId: 317046582

4 files changed, 60 insertions, 4 deletions

diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index a2190341c..51abe32a7 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -1033,14 +1033,14 @@ func (s *Stack) removeNICLocked(id tcpip.NICID) *tcpip.Error {
 	// Remove routes in-place. n tracks the number of routes written.
 	n := 0
 	for i, r := range s.routeTable {
+		s.routeTable[i] = tcpip.Route{}
 		if r.NIC != id {
 			// Keep this route.
-			if i > n {
-				s.routeTable[n] = r
-			}
+			s.routeTable[n] = r
 			n++
 		}
 	}
+
 	s.routeTable = s.routeTable[:n]
 
 	return nic.remove()
diff --git a/pkg/tcpip/transport/tcp/BUILD b/pkg/tcpip/transport/tcp/BUILD
index e26f01fae..6baeda8e4 100644
--- a/pkg/tcpip/transport/tcp/BUILD
+++ b/pkg/tcpip/transport/tcp/BUILD
@@ -76,7 +76,7 @@ go_library(
 )
 
 go_test(
-    name = "tcp_test",
+    name = "tcp_x_test",
     size = "medium",
     srcs = [
         "dual_stack_test.go",
@@ -115,3 +115,11 @@ go_test(
         "//pkg/tcpip/seqnum",
     ],
 )
+
+go_test(
+    name = "tcp_test",
+    size = "small",
+    srcs = ["timer_test.go"],
+    library = ":tcp",
+    deps = ["//pkg/sleep"],
+)
diff --git a/pkg/tcpip/transport/tcp/timer.go b/pkg/tcpip/transport/tcp/timer.go
index c70525f27..7981d469b 100644
--- a/pkg/tcpip/transport/tcp/timer.go
+++ b/pkg/tcpip/transport/tcp/timer.go
@@ -85,6 +85,7 @@ func (t *timer) init(w *sleep.Waker) {
 // cleanup frees all resources associated with the timer.
 func (t *timer) cleanup() {
 	t.timer.Stop()
+	*t = timer{}
 }
 
 // checkExpiration checks if the given timer has actually expired, it should be
diff --git a/pkg/tcpip/transport/tcp/timer_test.go b/pkg/tcpip/transport/tcp/timer_test.go
new file mode 100644
index 000000000..dbd6dff54
--- /dev/null
+++ b/pkg/tcpip/transport/tcp/timer_test.go
@@ -0,0 +1,47 @@
+// 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 tcp
+
+import (
+	"testing"
+	"time"
+
+	"gvisor.dev/gvisor/pkg/sleep"
+)
+
+func TestCleanup(t *testing.T) {
+	const (
+		timerDurationSeconds     = 2
+		isAssertedTimeoutSeconds = timerDurationSeconds + 1
+	)
+
+	tmr := timer{}
+	w := sleep.Waker{}
+	tmr.init(&w)
+	tmr.enable(timerDurationSeconds * time.Second)
+	tmr.cleanup()
+
+	if want := (timer{}); tmr != want {
+		t.Errorf("got tmr = %+v, want = %+v", tmr, want)
+	}
+
+	// The waker should not be asserted.
+	for i := 0; i < isAssertedTimeoutSeconds; i++ {
+		time.Sleep(time.Second)
+		if w.IsAsserted() {
+			t.Fatalf("waker asserted unexpectedly")
+		}
+	}
+}