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// Copyright 2012 Google, Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the LICENSE file in the root of the source
// tree.
package pcap
import (
"fmt"
"io"
"log"
"testing"
"code.google.com/p/gopacket"
"code.google.com/p/gopacket/layers"
)
func TestPcapFileRead(t *testing.T) {
for _, file := range []struct {
filename string
num int
expectedLayers []gopacket.LayerType
}{
{"test_loopback.pcap",
24,
[]gopacket.LayerType{
layers.LayerTypeLoopback,
layers.LayerTypeIPv6,
layers.LayerTypeTCP,
},
},
{"test_ethernet.pcap",
16,
[]gopacket.LayerType{
layers.LayerTypeEthernet,
layers.LayerTypeIPv4,
layers.LayerTypeTCP,
},
},
} {
t.Log("Processing file", file.filename)
packets := []gopacket.Packet{}
if handle, err := OpenOffline(file.filename); err != nil {
t.Fatal(err)
} else {
packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
for packet := range packetSource.Packets() {
packets = append(packets, packet)
}
}
if len(packets) != file.num {
t.Fatal("Incorrect number of packets, want", file.num, "got", len(packets))
}
for i, p := range packets {
t.Log("Packet ", i, "\n", p.Dump())
for _, layertype := range file.expectedLayers {
if p.Layer(layertype) == nil {
t.Error("Packet", i, "has no layer type", layertype)
}
}
}
}
}
func TestBPF(t *testing.T) {
handle, err := OpenOffline("test_ethernet.pcap")
if err != nil {
t.Fatal(err)
}
for _, expected := range []struct {
expr string
Error bool
Result bool
}{
{"foobar", true, false},
{"tcp[tcpflags] & (tcp-syn|tcp-ack) == (tcp-syn|tcp-ack)", false, true},
{"tcp[tcpflags] & (tcp-syn|tcp-ack) == tcp-ack", false, true},
{"udp", false, false},
} {
data, ci, err := handle.ReadPacketData()
if err != nil {
t.Fatal(err)
}
t.Log("Testing filter", expected.expr)
if bpf, err := handle.NewBPF(expected.expr); err != nil {
if !expected.Error {
t.Error(err, "while compiling filter was unexpected")
}
} else if expected.Error {
t.Error("expected error but didn't see one")
} else if matches := bpf.Matches(ci, data); matches != expected.Result {
t.Error("Filter result was", matches, "but should be", expected.Result)
}
}
}
func ExampleBPF() {
handle, err := OpenOffline("test_ethernet.pcap")
if err != nil {
log.Fatal(err)
}
synack, err := handle.NewBPF("tcp[tcpflags] & (tcp-syn|tcp-ack) == (tcp-syn|tcp-ack)")
if err != nil {
log.Fatal(err)
}
syn, err := handle.NewBPF("tcp[tcpflags] & (tcp-syn|tcp-ack) == tcp-syn")
if err != nil {
log.Fatal(err)
}
for {
data, ci, err := handle.ReadPacketData()
switch {
case err == io.EOF:
return
case err != nil:
log.Fatal(err)
case synack.Matches(ci, data):
fmt.Println("SYN/ACK packet")
case syn.Matches(ci, data):
fmt.Println("SYN packet")
default:
fmt.Println("SYN flag not set")
}
}
// Output:
// SYN packet
// SYN/ACK packet
// SYN flag not set
// SYN flag not set
// SYN flag not set
// SYN flag not set
// SYN flag not set
// SYN flag not set
// SYN flag not set
// SYN flag not set
// SYN flag not set
// SYN flag not set
// SYN flag not set
// SYN flag not set
// SYN flag not set
// SYN flag not set
}
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