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tailscale/wgengine/tstun/tun_test.go

313 lines
6.8 KiB
Go

// Copyright (c) 2020 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 tstun
import (
"bytes"
"sync/atomic"
"testing"
"unsafe"
"github.com/tailscale/wireguard-go/tun/tuntest"
"tailscale.com/net/packet"
"tailscale.com/types/logger"
"tailscale.com/wgengine/filter"
)
func udp(src, dst packet.IP4, sport, dport uint16) []byte {
header := &packet.UDP4Header{
IP4Header: packet.IP4Header{
SrcIP: src,
DstIP: dst,
IPID: 0,
},
SrcPort: sport,
DstPort: dport,
}
return packet.Generate(header, []byte("udp_payload"))
}
func filterNet(ip, mask packet.IP4) filter.Net {
return filter.Net{IP: ip, Mask: mask}
}
func nets(ips []packet.IP4) []filter.Net {
out := make([]filter.Net, 0, len(ips))
for _, ip := range ips {
out = append(out, filterNet(ip, filter.Netmask(32)))
}
return out
}
func ippr(ip packet.IP4, start, end uint16) []filter.NetPortRange {
return []filter.NetPortRange{
filter.NetPortRange{
Net: filterNet(ip, filter.Netmask(32)),
Ports: filter.PortRange{First: start, Last: end},
},
}
}
func setfilter(logf logger.Logf, tun *TUN) {
matches := filter.Matches{
{Srcs: nets([]packet.IP4{0x05060708}), Dsts: ippr(0x01020304, 89, 90)},
{Srcs: nets([]packet.IP4{0x01020304}), Dsts: ippr(0x05060708, 98, 98)},
}
localNets := []filter.Net{
filterNet(packet.IP4(0x01020304), filter.Netmask(16)),
}
tun.SetFilter(filter.New(matches, localNets, nil, logf))
}
func newChannelTUN(logf logger.Logf, secure bool) (*tuntest.ChannelTUN, *TUN) {
chtun := tuntest.NewChannelTUN()
tun := WrapTUN(logf, chtun.TUN())
if secure {
setfilter(logf, tun)
} else {
tun.disableFilter = true
}
return chtun, tun
}
func newFakeTUN(logf logger.Logf, secure bool) (*fakeTUN, *TUN) {
ftun := NewFakeTUN()
tun := WrapTUN(logf, ftun)
if secure {
setfilter(logf, tun)
} else {
tun.disableFilter = true
}
return ftun.(*fakeTUN), tun
}
func TestReadAndInject(t *testing.T) {
chtun, tun := newChannelTUN(t.Logf, false)
defer tun.Close()
const size = 2 // all payloads have this size
written := []string{"w0", "w1"}
injected := []string{"i0", "i1"}
go func() {
for _, packet := range written {
payload := []byte(packet)
chtun.Outbound <- payload
}
}()
for _, packet := range injected {
go func(packet string) {
payload := []byte(packet)
err := tun.InjectOutbound(payload)
if err != nil {
t.Errorf("%s: error: %v", packet, err)
}
}(packet)
}
var buf [MaxPacketSize]byte
var seen = make(map[string]bool)
// We expect the same packets back, in no particular order.
for i := 0; i < len(written)+len(injected); i++ {
n, err := tun.Read(buf[:], 0)
if err != nil {
t.Errorf("read %d: error: %v", i, err)
}
if n != size {
t.Errorf("read %d: got size %d; want %d", i, n, size)
}
got := string(buf[:n])
t.Logf("read %d: got %s", i, got)
seen[got] = true
}
for _, packet := range written {
if !seen[packet] {
t.Errorf("%s not received", packet)
}
}
for _, packet := range injected {
if !seen[packet] {
t.Errorf("%s not received", packet)
}
}
}
func TestWriteAndInject(t *testing.T) {
chtun, tun := newChannelTUN(t.Logf, false)
defer tun.Close()
const size = 2 // all payloads have this size
written := []string{"w0", "w1"}
injected := []string{"i0", "i1"}
go func() {
for _, packet := range written {
payload := []byte(packet)
n, err := tun.Write(payload, 0)
if err != nil {
t.Errorf("%s: error: %v", packet, err)
}
if n != size {
t.Errorf("%s: got size %d; want %d", packet, n, size)
}
}
}()
for _, packet := range injected {
go func(packet string) {
payload := []byte(packet)
err := tun.InjectInboundCopy(payload)
if err != nil {
t.Errorf("%s: error: %v", packet, err)
}
}(packet)
}
seen := make(map[string]bool)
// We expect the same packets back, in no particular order.
for i := 0; i < len(written)+len(injected); i++ {
packet := <-chtun.Inbound
got := string(packet)
t.Logf("read %d: got %s", i, got)
seen[got] = true
}
for _, packet := range written {
if !seen[packet] {
t.Errorf("%s not received", packet)
}
}
for _, packet := range injected {
if !seen[packet] {
t.Errorf("%s not received", packet)
}
}
}
func TestFilter(t *testing.T) {
chtun, tun := newChannelTUN(t.Logf, true)
defer tun.Close()
type direction int
const (
in direction = iota
out
)
tests := []struct {
name string
dir direction
drop bool
data []byte
}{
{"junk_in", in, true, []byte("\x45not a valid IPv4 packet")},
{"junk_out", out, true, []byte("\x45not a valid IPv4 packet")},
{"bad_port_in", in, true, udp(0x05060708, 0x01020304, 22, 22)},
{"bad_port_out", out, false, udp(0x01020304, 0x05060708, 22, 22)},
{"bad_ip_in", in, true, udp(0x08010101, 0x01020304, 89, 89)},
{"bad_ip_out", out, false, udp(0x01020304, 0x08010101, 98, 98)},
{"good_packet_in", in, false, udp(0x05060708, 0x01020304, 89, 89)},
{"good_packet_out", out, false, udp(0x01020304, 0x05060708, 98, 98)},
}
// A reader on the other end of the TUN.
go func() {
var recvbuf []byte
for {
select {
case <-tun.closed:
return
case recvbuf = <-chtun.Inbound:
// continue
}
for _, tt := range tests {
if tt.drop && bytes.Equal(recvbuf, tt.data) {
t.Errorf("did not drop %s", tt.name)
}
}
}
}()
var buf [MaxPacketSize]byte
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
var n int
var err error
var filtered bool
if tt.dir == in {
_, err = tun.Write(tt.data, 0)
if err == ErrFiltered {
filtered = true
err = nil
}
} else {
chtun.Outbound <- tt.data
n, err = tun.Read(buf[:], 0)
// In the read direction, errors are fatal, so we return n = 0 instead.
filtered = (n == 0)
}
if err != nil {
t.Errorf("got err %v; want nil", err)
}
if filtered {
if !tt.drop {
t.Errorf("got drop; want accept")
}
} else {
if tt.drop {
t.Errorf("got accept; want drop")
}
}
})
}
}
func TestAllocs(t *testing.T) {
ftun, tun := newFakeTUN(t.Logf, false)
defer tun.Close()
buf := []byte{0x00}
allocs := testing.AllocsPerRun(100, func() {
_, err := ftun.Write(buf, 0)
if err != nil {
t.Errorf("write: error: %v", err)
return
}
})
if allocs > 0 {
t.Errorf("read allocs = %v; want 0", allocs)
}
}
func BenchmarkWrite(b *testing.B) {
ftun, tun := newFakeTUN(b.Logf, true)
defer tun.Close()
packet := udp(0x05060708, 0x01020304, 89, 89)
for i := 0; i < b.N; i++ {
_, err := ftun.Write(packet, 0)
if err != nil {
b.Errorf("err = %v; want nil", err)
}
}
}
func TestAtomic64Alignment(t *testing.T) {
off := unsafe.Offsetof(TUN{}.lastActivityAtomic)
if off%8 != 0 {
t.Errorf("offset %v not 8-byte aligned", off)
}
c := new(TUN)
atomic.StoreInt64(&c.lastActivityAtomic, 123)
}