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tailscale/net/ping/ping_test.go

256 lines
5.2 KiB
Go

// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ping
import (
"context"
"errors"
"net"
"testing"
"time"
"golang.org/x/net/icmp"
"golang.org/x/net/ipv4"
"tailscale.com/tstest"
)
var (
localhost = &net.IPAddr{IP: net.IPv4(127, 0, 0, 1)}
localhostUDP = &net.UDPAddr{IP: net.IPv4(127, 0, 0, 1), Port: 12345}
)
func TestPinger(t *testing.T) {
clock := &tstest.Clock{}
ctx := context.Background()
ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
defer cancel()
p, closeP := mockPinger(t, clock)
defer closeP()
bodyData := []byte("data goes here")
// Start a ping in the background
r := make(chan time.Duration, 1)
go func() {
dur, err := p.Send(ctx, localhostUDP, bodyData)
if err != nil {
t.Errorf("p.Send: %v", err)
r <- 0
} else {
r <- dur
}
}()
p.waitOutstanding(t, ctx, 1)
// Fake a response from ourself
fakeResponse := mustMarshal(t, &icmp.Message{
Type: ipv4.ICMPTypeEchoReply,
Code: 0,
Body: &icmp.Echo{
ID: 1234,
Seq: 1,
Data: bodyData,
},
})
const fakeDuration = 100 * time.Millisecond
p.handleResponse(fakeResponse, localhost, clock.Now().Add(fakeDuration))
select {
case dur := <-r:
want := fakeDuration
if dur != want {
t.Errorf("wanted ping response time = %d; got %d", want, dur)
}
case <-ctx.Done():
t.Fatal("did not get response by timeout")
}
}
func TestPingerTimeout(t *testing.T) {
ctx := context.Background()
ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
defer cancel()
clock := &tstest.Clock{}
p, closeP := mockPinger(t, clock)
defer closeP()
// Send a ping in the background
r := make(chan error, 1)
go func() {
_, err := p.Send(ctx, localhostUDP, []byte("data goes here"))
r <- err
}()
// Wait until we're blocking
p.waitOutstanding(t, ctx, 1)
// Close everything down
p.cleanupOutstanding()
// Should have got an error from the ping
err := <-r
if !errors.Is(err, net.ErrClosed) {
t.Errorf("wanted errors.Is(err, net.ErrClosed); got=%v", err)
}
}
func TestPingerMismatch(t *testing.T) {
clock := &tstest.Clock{}
ctx := context.Background()
ctx, cancel := context.WithTimeout(ctx, 1*time.Second) // intentionally short
defer cancel()
p, closeP := mockPinger(t, clock)
defer closeP()
bodyData := []byte("data goes here")
// Start a ping in the background
r := make(chan time.Duration, 1)
go func() {
dur, err := p.Send(ctx, localhostUDP, bodyData)
if err != nil && !errors.Is(err, context.DeadlineExceeded) {
t.Errorf("p.Send: %v", err)
r <- 0
} else {
r <- dur
}
}()
p.waitOutstanding(t, ctx, 1)
// "Receive" a bunch of intentionally malformed packets that should not
// result in the Send call above returning
badPackets := []struct {
name string
pkt *icmp.Message
}{
{
name: "wrong type",
pkt: &icmp.Message{
Type: ipv4.ICMPTypeDestinationUnreachable,
Code: 0,
Body: &icmp.DstUnreach{},
},
},
{
name: "wrong id",
pkt: &icmp.Message{
Type: ipv4.ICMPTypeEchoReply,
Code: 0,
Body: &icmp.Echo{
ID: 9999,
Seq: 1,
Data: bodyData,
},
},
},
{
name: "wrong seq",
pkt: &icmp.Message{
Type: ipv4.ICMPTypeEchoReply,
Code: 0,
Body: &icmp.Echo{
ID: 1234,
Seq: 5,
Data: bodyData,
},
},
},
{
name: "bad body",
pkt: &icmp.Message{
Type: ipv4.ICMPTypeEchoReply,
Code: 0,
Body: &icmp.Echo{
ID: 1234,
Seq: 1,
// Intentionally missing first byte
Data: bodyData[1:],
},
},
},
}
const fakeDuration = 100 * time.Millisecond
tm := clock.Now().Add(fakeDuration)
for _, tt := range badPackets {
fakeResponse := mustMarshal(t, tt.pkt)
p.handleResponse(fakeResponse, localhost, tm)
}
// Also "receive" a packet that does not unmarshal as an ICMP packet
p.handleResponse([]byte("foo"), localhost, tm)
select {
case <-r:
t.Fatal("wanted timeout")
case <-ctx.Done():
t.Logf("test correctly timed out")
}
}
func mockPinger(t *testing.T, clock *tstest.Clock) (*Pinger, func()) {
// In tests, we use UDP so that we can test without being root; this
// doesn't matter becuase we mock out the ICMP reply below to be a real
// ICMP echo reply packet.
conn, err := net.ListenPacket("udp4", "127.0.0.1:0")
if err != nil {
t.Fatalf("net.ListenPacket: %v", err)
}
p := &Pinger{
c: conn,
Logf: t.Logf,
Verbose: true,
timeNow: clock.Now,
id: 1234,
pings: make(map[uint16]outstanding),
}
done := func() {
if err := p.Close(); err != nil {
t.Errorf("error on close: %v", err)
}
}
return p, done
}
func mustMarshal(t *testing.T, m *icmp.Message) []byte {
t.Helper()
b, err := m.Marshal(nil)
if err != nil {
t.Fatal(err)
}
return b
}
func (p *Pinger) waitOutstanding(t *testing.T, ctx context.Context, count int) {
// This is a bit janky, but... we busy-loop to wait for the Send call
// to write to our map so we know that a response will be handled.
var haveMapEntry bool
for !haveMapEntry {
time.Sleep(10 * time.Millisecond)
select {
case <-ctx.Done():
t.Error("no entry in ping map before timeout")
return
default:
}
p.mu.Lock()
haveMapEntry = len(p.pings) == count
p.mu.Unlock()
}
}