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// Copyright 2019 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 header provides the implementation of the encoding and decoding of
// network protocol headers.
package header_test
import (
"bytes"
"fmt"
"math/rand"
"sync"
"testing"
"gvisor.dev/gvisor/pkg/tcpip/buffer"
"gvisor.dev/gvisor/pkg/tcpip/header"
)
func TestChecksumer(t *testing.T) {
testCases := []struct {
name string
data [][]byte
want uint16
}{
{
name: "empty",
want: 0,
},
{
name: "OneOddView",
data: [][]byte{
[]byte{1, 9, 0, 5, 4},
},
want: 1294,
},
{
name: "TwoOddViews",
data: [][]byte{
[]byte{1, 9, 0, 5, 4},
[]byte{4, 3, 7, 1, 2, 123},
},
want: 33819,
},
{
name: "OneEvenView",
data: [][]byte{
[]byte{1, 9, 0, 5},
},
want: 270,
},
{
name: "TwoEvenViews",
data: [][]byte{
buffer.NewViewFromBytes([]byte{98, 1, 9, 0}),
buffer.NewViewFromBytes([]byte{9, 0, 5, 4}),
},
want: 30981,
},
{
name: "ThreeViews",
data: [][]byte{
[]byte{77, 11, 33, 0, 55, 44},
[]byte{98, 1, 9, 0, 5, 4},
[]byte{4, 3, 7, 1, 2, 123, 99},
},
want: 34236,
},
}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
var all bytes.Buffer
var c header.Checksumer
for _, b := range tc.data {
c.Add(b)
// Append to the buffer. We will check the checksum as a whole later.
if _, err := all.Write(b); err != nil {
t.Fatalf("all.Write(b) = _, %s; want _, nil", err)
}
}
if got, want := c.Checksum(), tc.want; got != want {
t.Errorf("c.Checksum() = %d, want %d", got, want)
}
if got, want := header.Checksum(all.Bytes(), 0 /* initial */), tc.want; got != want {
t.Errorf("Checksum(flatten tc.data) = %d, want %d", got, want)
}
})
}
}
func TestChecksum(t *testing.T) {
var bufSizes = []int{0, 1, 2, 3, 4, 7, 8, 15, 16, 31, 32, 63, 64, 127, 128, 255, 256, 257, 1023, 1024}
type testCase struct {
buf []byte
initial uint16
csumOrig uint16
csumNew uint16
}
testCases := make([]testCase, 100000)
// Ensure same buffer generation for test consistency.
rnd := rand.New(rand.NewSource(42))
for i := range testCases {
testCases[i].buf = make([]byte, bufSizes[i%len(bufSizes)])
testCases[i].initial = uint16(rnd.Intn(65536))
rnd.Read(testCases[i].buf)
}
for i := range testCases {
testCases[i].csumOrig = header.ChecksumOld(testCases[i].buf, testCases[i].initial)
testCases[i].csumNew = header.Checksum(testCases[i].buf, testCases[i].initial)
if got, want := testCases[i].csumNew, testCases[i].csumOrig; got != want {
t.Fatalf("new checksum for (buf = %x, initial = %d) does not match old got: %d, want: %d", testCases[i].buf, testCases[i].initial, got, want)
}
}
}
func BenchmarkChecksum(b *testing.B) {
var bufSizes = []int{64, 128, 256, 512, 1024, 1500, 2048, 4096, 8192, 16384, 32767, 32768, 65535, 65536}
checkSumImpls := []struct {
fn func([]byte, uint16) uint16
name string
}{
{header.ChecksumOld, fmt.Sprintf("checksum_old")},
{header.Checksum, fmt.Sprintf("checksum")},
}
for _, csumImpl := range checkSumImpls {
// Ensure same buffer generation for test consistency.
rnd := rand.New(rand.NewSource(42))
for _, bufSz := range bufSizes {
b.Run(fmt.Sprintf("%s_%d", csumImpl.name, bufSz), func(b *testing.B) {
tc := struct {
buf []byte
initial uint16
csum uint16
}{
buf: make([]byte, bufSz),
initial: uint16(rnd.Intn(65536)),
}
rnd.Read(tc.buf)
b.ResetTimer()
for i := 0; i < b.N; i++ {
tc.csum = csumImpl.fn(tc.buf, tc.initial)
}
})
}
}
}
func testICMPChecksum(t *testing.T, headerChecksum func() uint16, icmpChecksum func() uint16, want uint16, pktStr string) {
// icmpChecksum should not do any modifications of the header to
// calculate its checksum. Let's call it from a few go-routines and the
// race detector will trigger a warning if there are any concurrent
// read/write accesses.
const concurrency = 5
start := make(chan int)
ready := make(chan bool, concurrency)
var wg sync.WaitGroup
wg.Add(concurrency)
defer wg.Wait()
for i := 0; i < concurrency; i++ {
go func() {
defer wg.Done()
ready <- true
<-start
if got := headerChecksum(); want != got {
t.Errorf("new checksum for %s does not match old got: %x, want: %x", pktStr, got, want)
}
if got := icmpChecksum(); want != got {
t.Errorf("new checksum for %s does not match old got: %x, want: %x", pktStr, got, want)
}
}()
}
for i := 0; i < concurrency; i++ {
<-ready
}
close(start)
}
func TestICMPv4Checksum(t *testing.T) {
rnd := rand.New(rand.NewSource(42))
h := header.ICMPv4(make([]byte, header.ICMPv4MinimumSize))
if _, err := rnd.Read(h); err != nil {
t.Fatalf("rnd.Read failed: %v", err)
}
h.SetChecksum(0)
buf := make([]byte, 13)
if _, err := rnd.Read(buf); err != nil {
t.Fatalf("rnd.Read failed: %v", err)
}
vv := buffer.NewVectorisedView(len(buf), []buffer.View{
buffer.NewViewFromBytes(buf[:5]),
buffer.NewViewFromBytes(buf[5:]),
})
want := header.Checksum(vv.ToView(), 0)
want = ^header.Checksum(h, want)
h.SetChecksum(want)
testICMPChecksum(t, h.Checksum, func() uint16 {
return header.ICMPv4Checksum(h, header.ChecksumVV(vv, 0))
}, want, fmt.Sprintf("header: {% x} data {% x}", h, vv.ToView()))
}
func TestICMPv6Checksum(t *testing.T) {
rnd := rand.New(rand.NewSource(42))
h := header.ICMPv6(make([]byte, header.ICMPv6MinimumSize))
if _, err := rnd.Read(h); err != nil {
t.Fatalf("rnd.Read failed: %v", err)
}
h.SetChecksum(0)
buf := make([]byte, 13)
if _, err := rnd.Read(buf); err != nil {
t.Fatalf("rnd.Read failed: %v", err)
}
vv := buffer.NewVectorisedView(len(buf), []buffer.View{
buffer.NewViewFromBytes(buf[:7]),
buffer.NewViewFromBytes(buf[7:10]),
buffer.NewViewFromBytes(buf[10:]),
})
dst := header.IPv6Loopback
src := header.IPv6Loopback
want := header.PseudoHeaderChecksum(header.ICMPv6ProtocolNumber, src, dst, uint16(len(h)+vv.Size()))
want = header.Checksum(vv.ToView(), want)
want = ^header.Checksum(h, want)
h.SetChecksum(want)
testICMPChecksum(t, h.Checksum, func() uint16 {
return header.ICMPv6Checksum(header.ICMPv6ChecksumParams{
Header: h,
Src: src,
Dst: dst,
PayloadCsum: header.ChecksumVV(vv, 0),
PayloadLen: vv.Size(),
})
}, want, fmt.Sprintf("header: {% x} data {% x}", h, vv.ToView()))
}
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