netboot/dhcp4/packet_test.go

121 lines
3.0 KiB
Go

// Copyright 2016 Google Inc.
//
// 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 dhcp4
import (
"bytes"
"errors"
"io/ioutil"
"os"
"reflect"
"testing"
"go.universe.tf/netboot/pcap"
)
func udpFromPcap(fname string) ([][]byte, error) {
f, err := os.Open(fname)
if err != nil {
return nil, err
}
r, err := pcap.NewReader(f)
if err != nil {
return nil, err
}
if r.LinkType != pcap.LinkEthernet {
return nil, errors.New("Pcap packets are not ethernet")
}
ret := [][]byte{}
for r.Next() {
// Assume here that the packets are UDPv4, and just chop off
// the headers in front of the UDP payload
pkt := r.Packet()
hdrLen := 14 // Ethernet header
hdrLen += int(pkt.Bytes[hdrLen]&0xF) * 4 // IP header
hdrLen += 8 // UDP header
ret = append(ret, pkt.Bytes[hdrLen:])
}
if r.Err() != nil {
return nil, r.Err()
}
return ret, nil
}
func TestParse(t *testing.T) {
rawPkts, err := udpFromPcap("testdata/dhcp.pcap")
if err != nil {
t.Fatalf("Getting test packets from pcap: %s", err)
}
var pkts bytes.Buffer
for i, rawPkt := range rawPkts {
pkt, err := Unmarshal(rawPkt)
if err != nil {
t.Fatalf("Parsing DHCP packet #%d: %s", i+1, err)
}
pkts.WriteString(pkt.DebugString())
pkts.WriteString("======\n")
}
expectedFile := "testdata/dhcp.parsed"
expected, err := ioutil.ReadFile(expectedFile)
if err != nil {
t.Fatalf("Reading expected file: %s", err)
}
if pkts.String() != string(expected) {
if os.Getenv("UPDATE_TESTDATA") != "" {
ioutil.WriteFile(expectedFile, pkts.Bytes(), 0644)
t.Errorf("dhcp.pcap didn't decode to dhcp.parsed (updated dhcp.parsed)")
} else {
t.Fatalf("dhcp.pcap didn't decode to dhcp.parsed (rerun with UPDATE_TESTDATA=1 to get diff)")
}
}
}
func TestWriteRead(t *testing.T) {
rawPkts, err := udpFromPcap("testdata/dhcp.pcap")
if err != nil {
t.Fatalf("Getting test packets from pcap: %s", err)
}
var pkts []*Packet
for i, rawPkt := range rawPkts {
pkt, err := Unmarshal(rawPkt)
if err != nil {
t.Fatalf("Unmarshalling testdata packet #%d: %s", i+1, err)
}
pkts = append(pkts, pkt)
}
for _, pkt := range pkts {
raw, err := pkt.Marshal()
if err != nil {
t.Fatalf("Packet marshalling failed: %s\nPacket: %#v", err, pkt)
}
pkt2, err := Unmarshal(raw)
if err != nil {
t.Fatalf("Packet unmarshalling failed: %s\nPacket: %#v", err, pkt)
}
if !reflect.DeepEqual(pkt, pkt2) {
t.Fatalf("Packet mutated by write-then-read: %#v", pkt)
}
}
}