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// 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 header_test
import (
"testing"
"github.com/google/go-cmp/cmp"
"gvisor.dev/gvisor/pkg/tcpip/buffer"
"gvisor.dev/gvisor/pkg/tcpip/header"
)
func TestIPv4OptionsSerializer(t *testing.T) {
optCases := []struct {
name string
option []header.IPv4SerializableOption
expect []byte
}{
{
name: "NOP",
option: []header.IPv4SerializableOption{
&header.IPv4SerializableNOPOption{},
},
expect: []byte{1, 0, 0, 0},
},
{
name: "ListEnd",
option: []header.IPv4SerializableOption{
&header.IPv4SerializableListEndOption{},
},
expect: []byte{0, 0, 0, 0},
},
{
name: "RouterAlert",
option: []header.IPv4SerializableOption{
&header.IPv4SerializableRouterAlertOption{},
},
expect: []byte{148, 4, 0, 0},
}, {
name: "NOP and RouterAlert",
option: []header.IPv4SerializableOption{
&header.IPv4SerializableNOPOption{},
&header.IPv4SerializableRouterAlertOption{},
},
expect: []byte{1, 148, 4, 0, 0, 0, 0, 0},
},
}
for _, opt := range optCases {
t.Run(opt.name, func(t *testing.T) {
s := header.IPv4OptionsSerializer(opt.option)
l := s.Length()
if got := len(opt.expect); got != int(l) {
t.Fatalf("s.Length() = %d, want = %d", got, l)
}
b := make([]byte, l)
for i := range b {
// Fill the buffer with full bytes to ensure padding is being set
// correctly.
b[i] = 0xFF
}
if serializedLength := s.Serialize(b); serializedLength != l {
t.Fatalf("s.Serialize(_) = %d, want %d", serializedLength, l)
}
if diff := cmp.Diff(opt.expect, b); diff != "" {
t.Errorf("mismatched serialized option (-want +got):\n%s", diff)
}
})
}
}
// TestIPv4Encode checks that ipv4.Encode correctly fills out the requested
// fields when options are supplied.
func TestIPv4EncodeOptions(t *testing.T) {
tests := []struct {
name string
numberOfNops int
encodedOptions header.IPv4Options // reply should look like this
wantIHL int
}{
{
name: "valid no options",
wantIHL: header.IPv4MinimumSize,
},
{
name: "one byte options",
numberOfNops: 1,
encodedOptions: header.IPv4Options{1, 0, 0, 0},
wantIHL: header.IPv4MinimumSize + 4,
},
{
name: "two byte options",
numberOfNops: 2,
encodedOptions: header.IPv4Options{1, 1, 0, 0},
wantIHL: header.IPv4MinimumSize + 4,
},
{
name: "three byte options",
numberOfNops: 3,
encodedOptions: header.IPv4Options{1, 1, 1, 0},
wantIHL: header.IPv4MinimumSize + 4,
},
{
name: "four byte options",
numberOfNops: 4,
encodedOptions: header.IPv4Options{1, 1, 1, 1},
wantIHL: header.IPv4MinimumSize + 4,
},
{
name: "five byte options",
numberOfNops: 5,
encodedOptions: header.IPv4Options{1, 1, 1, 1, 1, 0, 0, 0},
wantIHL: header.IPv4MinimumSize + 8,
},
{
name: "thirty nine byte options",
numberOfNops: 39,
encodedOptions: header.IPv4Options{
1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 0,
},
wantIHL: header.IPv4MinimumSize + 40,
},
}
for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
serializeOpts := header.IPv4OptionsSerializer(make([]header.IPv4SerializableOption, test.numberOfNops))
for i := range serializeOpts {
serializeOpts[i] = &header.IPv4SerializableNOPOption{}
}
paddedOptionLength := serializeOpts.Length()
ipHeaderLength := int(header.IPv4MinimumSize + paddedOptionLength)
if ipHeaderLength > header.IPv4MaximumHeaderSize {
t.Fatalf("IP header length too large: got = %d, want <= %d ", ipHeaderLength, header.IPv4MaximumHeaderSize)
}
totalLen := uint16(ipHeaderLength)
hdr := buffer.NewPrependable(int(totalLen))
ip := header.IPv4(hdr.Prepend(ipHeaderLength))
// To check the padding works, poison the last byte of the options space.
if paddedOptionLength != serializeOpts.Length() {
ip.SetHeaderLength(uint8(ipHeaderLength))
ip.Options()[paddedOptionLength-1] = 0xff
ip.SetHeaderLength(0)
}
ip.Encode(&header.IPv4Fields{
Options: serializeOpts,
})
options := ip.Options()
wantOptions := test.encodedOptions
if got, want := int(ip.HeaderLength()), test.wantIHL; got != want {
t.Errorf("got IHL of %d, want %d", got, want)
}
// cmp.Diff does not consider nil slices equal to empty slices, but we do.
if len(wantOptions) == 0 && len(options) == 0 {
return
}
if diff := cmp.Diff(wantOptions, options); diff != "" {
t.Errorf("options mismatch (-want +got):\n%s", diff)
}
})
}
}
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