1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
// 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.
// The pcaplay binary load an offline capture (pcap file) and replay
// it on the select interface, with an emphasis on packet timing
package main
import (
"flag"
"fmt"
"io"
"log"
"os"
"strings"
"time"
"github.com/gopacket/gopacket"
"github.com/gopacket/gopacket/examples/util"
"github.com/gopacket/gopacket/pcap"
)
var iface = flag.String("i", "eth0", "Interface to write packets to")
var fname = flag.String("r", "", "Filename to read from")
var fast = flag.Bool("f", false, "Send each packets as fast as possible")
var lastTS time.Time
var lastSend time.Time
var start time.Time
var bytesSent int
func writePacketDelayed(handle *pcap.Handle, buf []byte, ci gopacket.CaptureInfo) {
if ci.CaptureLength != ci.Length {
// do not write truncated packets
return
}
intervalInCapture := ci.Timestamp.Sub(lastTS)
elapsedTime := time.Since(lastSend)
if (intervalInCapture > elapsedTime) && !lastSend.IsZero() {
time.Sleep(intervalInCapture - elapsedTime)
}
lastSend = time.Now()
writePacket(handle, buf)
lastTS = ci.Timestamp
}
func writePacket(handle *pcap.Handle, buf []byte) error {
if err := handle.WritePacketData(buf); err != nil {
log.Printf("Failed to send packet: %s\n", err)
return err
}
return nil
}
func pcapInfo(filename string) (start time.Time, end time.Time, packets int, size int) {
handleRead, err := pcap.OpenOffline(*fname)
if err != nil {
log.Fatal("PCAP OpenOffline error (handle to read packet):", err)
}
var previousTs time.Time
var deltaTotal time.Duration
for {
data, ci, err := handleRead.ReadPacketData()
if err != nil && err != io.EOF {
log.Fatal(err)
} else if err == io.EOF {
break
} else {
if start.IsZero() {
start = ci.Timestamp
}
end = ci.Timestamp
packets++
size += len(data)
if previousTs.IsZero() {
previousTs = ci.Timestamp
} else {
deltaTotal += ci.Timestamp.Sub(previousTs)
previousTs = ci.Timestamp
}
}
}
sec := int(deltaTotal.Seconds())
if sec == 0 {
sec = 1
}
fmt.Printf("Avg packet rate %d/s\n", packets/sec)
return start, end, packets, size
}
func main() {
defer util.Run()()
// Sanity checks
if *fname == "" {
log.Fatal("Need a input file")
}
// Open PCAP file + handle potential BPF Filter
handleRead, err := pcap.OpenOffline(*fname)
if err != nil {
log.Fatal("PCAP OpenOffline error (handle to read packet):", err)
}
defer handleRead.Close()
if len(flag.Args()) > 0 {
bpffilter := strings.Join(flag.Args(), " ")
fmt.Fprintf(os.Stderr, "Using BPF filter %q\n", bpffilter)
if err = handleRead.SetBPFFilter(bpffilter); err != nil {
log.Fatal("BPF filter error:", err)
}
}
// Open up a second pcap handle for packet writes.
handleWrite, err := pcap.OpenLive(*iface, 65536, true, pcap.BlockForever)
if err != nil {
log.Fatal("PCAP OpenLive error (handle to write packet):", err)
}
defer handleWrite.Close()
start = time.Now()
pkt := 0
tsStart, tsEnd, packets, size := pcapInfo(*fname)
// Loop over packets and write them
for {
data, ci, err := handleRead.ReadPacketData()
switch {
case err == io.EOF:
fmt.Printf("\nFinished in %s", time.Since(start))
return
case err != nil:
log.Printf("Failed to read packet %d: %s\n", pkt, err)
default:
if *fast {
writePacket(handleWrite, data)
} else {
writePacketDelayed(handleWrite, data, ci)
}
bytesSent += len(data)
duration := time.Since(start)
pkt++
if duration > time.Second {
rate := bytesSent / int(duration.Seconds())
remainingTime := tsEnd.Sub(tsStart) - duration
fmt.Printf("\rrate %d kB/sec - sent %d/%d kB - %d/%d packets - remaining time %s",
rate/1000, bytesSent/1000, size/1000,
pkt, packets, remainingTime)
}
}
}
}
|
