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// Copyright 2018 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 stack
import (
"fmt"
"sync"
"testing"
"time"
"gvisor.dev/gvisor/pkg/sleep"
"gvisor.dev/gvisor/pkg/tcpip"
)
type testaddr struct {
addr tcpip.FullAddress
linkAddr tcpip.LinkAddress
}
var testaddrs []testaddr
type testLinkAddressResolver struct {
cache *linkAddrCache
delay time.Duration
}
func (r *testLinkAddressResolver) LinkAddressRequest(addr, _ tcpip.Address, _ LinkEndpoint) *tcpip.Error {
go func() {
if r.delay > 0 {
time.Sleep(r.delay)
}
r.fakeRequest(addr)
}()
return nil
}
func (r *testLinkAddressResolver) fakeRequest(addr tcpip.Address) {
for _, ta := range testaddrs {
if ta.addr.Addr == addr {
r.cache.add(ta.addr, ta.linkAddr)
break
}
}
}
func (*testLinkAddressResolver) ResolveStaticAddress(addr tcpip.Address) (tcpip.LinkAddress, bool) {
if addr == "broadcast" {
return "mac_broadcast", true
}
return "", false
}
func (*testLinkAddressResolver) LinkAddressProtocol() tcpip.NetworkProtocolNumber {
return 1
}
func getBlocking(c *linkAddrCache, addr tcpip.FullAddress, linkRes LinkAddressResolver) (tcpip.LinkAddress, *tcpip.Error) {
w := sleep.Waker{}
s := sleep.Sleeper{}
s.AddWaker(&w, 123)
defer s.Done()
for {
if got, _, err := c.get(addr, linkRes, "", nil, &w); err != tcpip.ErrWouldBlock {
return got, err
}
s.Fetch(true)
}
}
func init() {
for i := 0; i < 4*linkAddrCacheSize; i++ {
addr := fmt.Sprintf("Addr%06d", i)
testaddrs = append(testaddrs, testaddr{
addr: tcpip.FullAddress{NIC: 1, Addr: tcpip.Address(addr)},
linkAddr: tcpip.LinkAddress("Link" + addr),
})
}
}
func TestCacheOverflow(t *testing.T) {
c := newLinkAddrCache(1<<63-1, 1*time.Second, 3)
for i := len(testaddrs) - 1; i >= 0; i-- {
e := testaddrs[i]
c.add(e.addr, e.linkAddr)
got, _, err := c.get(e.addr, nil, "", nil, nil)
if err != nil {
t.Errorf("insert %d, c.get(%q)=%q, got error: %v", i, string(e.addr.Addr), got, err)
}
if got != e.linkAddr {
t.Errorf("insert %d, c.get(%q)=%q, want %q", i, string(e.addr.Addr), got, e.linkAddr)
}
}
// Expect to find at least half of the most recent entries.
for i := 0; i < linkAddrCacheSize/2; i++ {
e := testaddrs[i]
got, _, err := c.get(e.addr, nil, "", nil, nil)
if err != nil {
t.Errorf("check %d, c.get(%q)=%q, got error: %v", i, string(e.addr.Addr), got, err)
}
if got != e.linkAddr {
t.Errorf("check %d, c.get(%q)=%q, want %q", i, string(e.addr.Addr), got, e.linkAddr)
}
}
// The earliest entries should no longer be in the cache.
for i := len(testaddrs) - 1; i >= len(testaddrs)-linkAddrCacheSize; i-- {
e := testaddrs[i]
if _, _, err := c.get(e.addr, nil, "", nil, nil); err != tcpip.ErrNoLinkAddress {
t.Errorf("check %d, c.get(%q), got error: %v, want: error ErrNoLinkAddress", i, string(e.addr.Addr), err)
}
}
}
func TestCacheConcurrent(t *testing.T) {
c := newLinkAddrCache(1<<63-1, 1*time.Second, 3)
var wg sync.WaitGroup
for r := 0; r < 16; r++ {
wg.Add(1)
go func() {
for _, e := range testaddrs {
c.add(e.addr, e.linkAddr)
c.get(e.addr, nil, "", nil, nil) // make work for gotsan
}
wg.Done()
}()
}
wg.Wait()
// All goroutines add in the same order and add more values than
// can fit in the cache, so our eviction strategy requires that
// the last entry be present and the first be missing.
e := testaddrs[len(testaddrs)-1]
got, _, err := c.get(e.addr, nil, "", nil, nil)
if err != nil {
t.Errorf("c.get(%q)=%q, got error: %v", string(e.addr.Addr), got, err)
}
if got != e.linkAddr {
t.Errorf("c.get(%q)=%q, want %q", string(e.addr.Addr), got, e.linkAddr)
}
e = testaddrs[0]
if _, _, err := c.get(e.addr, nil, "", nil, nil); err != tcpip.ErrNoLinkAddress {
t.Errorf("c.get(%q), got error: %v, want: error ErrNoLinkAddress", string(e.addr.Addr), err)
}
}
func TestCacheAgeLimit(t *testing.T) {
c := newLinkAddrCache(1*time.Millisecond, 1*time.Second, 3)
e := testaddrs[0]
c.add(e.addr, e.linkAddr)
time.Sleep(50 * time.Millisecond)
if _, _, err := c.get(e.addr, nil, "", nil, nil); err != tcpip.ErrNoLinkAddress {
t.Errorf("c.get(%q), got error: %v, want: error ErrNoLinkAddress", string(e.addr.Addr), err)
}
}
func TestCacheReplace(t *testing.T) {
c := newLinkAddrCache(1<<63-1, 1*time.Second, 3)
e := testaddrs[0]
l2 := e.linkAddr + "2"
c.add(e.addr, e.linkAddr)
got, _, err := c.get(e.addr, nil, "", nil, nil)
if err != nil {
t.Errorf("c.get(%q)=%q, got error: %v", string(e.addr.Addr), got, err)
}
if got != e.linkAddr {
t.Errorf("c.get(%q)=%q, want %q", string(e.addr.Addr), got, e.linkAddr)
}
c.add(e.addr, l2)
got, _, err = c.get(e.addr, nil, "", nil, nil)
if err != nil {
t.Errorf("c.get(%q)=%q, got error: %v", string(e.addr.Addr), got, err)
}
if got != l2 {
t.Errorf("c.get(%q)=%q, want %q", string(e.addr.Addr), got, l2)
}
}
func TestCacheResolution(t *testing.T) {
c := newLinkAddrCache(1<<63-1, 250*time.Millisecond, 1)
linkRes := &testLinkAddressResolver{cache: c}
for i, ta := range testaddrs {
got, err := getBlocking(c, ta.addr, linkRes)
if err != nil {
t.Errorf("check %d, c.get(%q)=%q, got error: %v", i, string(ta.addr.Addr), got, err)
}
if got != ta.linkAddr {
t.Errorf("check %d, c.get(%q)=%q, want %q", i, string(ta.addr.Addr), got, ta.linkAddr)
}
}
// Check that after resolved, address stays in the cache and never returns WouldBlock.
for i := 0; i < 10; i++ {
e := testaddrs[len(testaddrs)-1]
got, _, err := c.get(e.addr, linkRes, "", nil, nil)
if err != nil {
t.Errorf("c.get(%q)=%q, got error: %v", string(e.addr.Addr), got, err)
}
if got != e.linkAddr {
t.Errorf("c.get(%q)=%q, want %q", string(e.addr.Addr), got, e.linkAddr)
}
}
}
func TestCacheResolutionFailed(t *testing.T) {
c := newLinkAddrCache(1<<63-1, 10*time.Millisecond, 5)
linkRes := &testLinkAddressResolver{cache: c}
// First, sanity check that resolution is working...
e := testaddrs[0]
got, err := getBlocking(c, e.addr, linkRes)
if err != nil {
t.Errorf("c.get(%q)=%q, got error: %v", string(e.addr.Addr), got, err)
}
if got != e.linkAddr {
t.Errorf("c.get(%q)=%q, want %q", string(e.addr.Addr), got, e.linkAddr)
}
e.addr.Addr += "2"
if _, err := getBlocking(c, e.addr, linkRes); err != tcpip.ErrNoLinkAddress {
t.Errorf("c.get(%q), got error: %v, want: error ErrNoLinkAddress", string(e.addr.Addr), err)
}
}
func TestCacheResolutionTimeout(t *testing.T) {
resolverDelay := 500 * time.Millisecond
expiration := resolverDelay / 10
c := newLinkAddrCache(expiration, 1*time.Millisecond, 3)
linkRes := &testLinkAddressResolver{cache: c, delay: resolverDelay}
e := testaddrs[0]
if _, err := getBlocking(c, e.addr, linkRes); err != tcpip.ErrNoLinkAddress {
t.Errorf("c.get(%q), got error: %v, want: error ErrNoLinkAddress", string(e.addr.Addr), err)
}
}
// TestStaticResolution checks that static link addresses are resolved immediately and don't
// send resolution requests.
func TestStaticResolution(t *testing.T) {
c := newLinkAddrCache(1<<63-1, time.Millisecond, 1)
linkRes := &testLinkAddressResolver{cache: c, delay: time.Minute}
addr := tcpip.Address("broadcast")
want := tcpip.LinkAddress("mac_broadcast")
got, _, err := c.get(tcpip.FullAddress{Addr: addr}, linkRes, "", nil, nil)
if err != nil {
t.Errorf("c.get(%q)=%q, got error: %v", string(addr), string(got), err)
}
if got != want {
t.Errorf("c.get(%q)=%q, want %q", string(addr), string(got), string(want))
}
}
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