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
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
package main
import (
"context"
"errors"
"github.com/google/gopacket"
"github.com/google/gopacket/layers"
"github.com/google/gopacket/pcap"
"github.com/google/gopacket/tcpassembly"
"go.mongodb.org/mongo-driver/mongo"
"log"
"net"
"strconv"
"sync"
"time"
)
const initialAssemblerPoolSize = 16
const flushOlderThan = 5 * time.Minute
const invalidSessionId = "invalid_id"
const importUpdateProgressInterval = 3 * time.Second
const initialPacketPerServicesMapSize = 16
const importedPcapsCollectionName = "imported_pcaps"
type PcapImporter struct {
storage Storage
streamPool *tcpassembly.StreamPool
assemblers []*tcpassembly.Assembler
sessions map[string]context.CancelFunc
mAssemblers sync.Mutex
mSessions sync.Mutex
serverIp gopacket.Endpoint
}
type flowCount [2]int
func NewPcapImporter(storage Storage, serverIp net.IP) *PcapImporter {
serverEndpoint := layers.NewIPEndpoint(serverIp)
streamFactory := &BiDirectionalStreamFactory{
storage: storage,
serverIp: serverEndpoint,
}
streamPool := tcpassembly.NewStreamPool(streamFactory)
return &PcapImporter{
storage: storage,
streamPool: streamPool,
assemblers: make([]*tcpassembly.Assembler, 0, initialAssemblerPoolSize),
sessions: make(map[string]context.CancelFunc),
mAssemblers: sync.Mutex{},
mSessions: sync.Mutex{},
serverIp: serverEndpoint,
}
}
// Import a pcap file to the database. The pcap file must be present at the fileName path. If the pcap is already
// going to be imported or if it has been already imported in the past the function returns an error. Otherwise it
// create a new session and starts to import the pcap, and returns immediately the session name (that is the sha256
// of the pcap).
func (pi *PcapImporter) ImportPcap(fileName string) (string, error) {
hash, err := Sha256Sum(fileName)
if err != nil {
return invalidSessionId, err
}
pi.mSessions.Lock()
_, ok := pi.sessions[hash]
if ok {
pi.mSessions.Unlock()
return hash, errors.New("another equal session in progress")
}
doc := OrderedDocument{
{"_id", hash},
{"started_at", time.Now()},
{"completed_at", nil},
{"processed_packets", 0},
{"invalid_packets", 0},
{"packets_per_services", nil},
{"importing_error", err},
}
ctx, canc := context.WithCancel(context.Background())
_, err = pi.storage.InsertOne(ctx, importedPcapsCollectionName, doc)
if err != nil {
pi.mSessions.Unlock()
_, alreadyProcessed := err.(mongo.WriteException)
if alreadyProcessed {
return hash, errors.New("pcap already processed")
}
return hash, err
}
pi.sessions[hash] = canc
pi.mSessions.Unlock()
go pi.parsePcap(hash, fileName, ctx)
return hash, nil
}
func (pi *PcapImporter) CancelImport(sessionId string) error {
pi.mSessions.Lock()
defer pi.mSessions.Unlock()
cancel, ok := pi.sessions[sessionId]
if ok {
delete(pi.sessions, sessionId)
cancel()
return nil
} else {
return errors.New("session " + sessionId + " not found")
}
}
// Read the pcap and save the tcp stream flow to the database
func (pi *PcapImporter) parsePcap(sessionId, fileName string, ctx context.Context) {
handle, err := pcap.OpenOffline(fileName)
if err != nil {
// TODO: update db and set error
return
}
packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
packetSource.NoCopy = true
assembler := pi.takeAssembler()
packets := packetSource.Packets()
firstPacketTime := time.Time{}
updateProgressInterval := time.Tick(importUpdateProgressInterval)
processedPackets := 0
invalidPackets := 0
packetsPerService := make(map[int]*flowCount, initialPacketPerServicesMapSize)
progressUpdate := func(completed bool, err error) {
update := UnorderedDocument{
"processed_packets": processedPackets,
"invalid_packets": invalidPackets,
"packets_per_services": packetsPerService,
"importing_error": err,
}
if completed {
update["completed_at"] = time.Now()
}
_, _err := pi.storage.UpdateOne(nil, importedPcapsCollectionName, OrderedDocument{{"_id", sessionId}},
completed, false)
if _err != nil {
log.Println("can't update importing statistics : ", _err)
}
}
deleteSession := func() {
pi.mSessions.Lock()
delete(pi.sessions, sessionId)
pi.mSessions.Unlock()
}
for {
select {
case <- ctx.Done():
handle.Close()
deleteSession()
progressUpdate(false, errors.New("import process cancelled"))
return
default:
}
select {
case packet := <-packets:
if packet == nil { // completed
if !firstPacketTime.IsZero() {
assembler.FlushOlderThan(firstPacketTime.Add(-flushOlderThan))
}
pi.releaseAssembler(assembler)
handle.Close()
deleteSession()
progressUpdate(true, nil)
return
}
processedPackets++
if packet.NetworkLayer() == nil || packet.TransportLayer() == nil ||
packet.TransportLayer().LayerType() != layers.LayerTypeTCP { // invalid packet
invalidPackets++
continue
}
timestamp := packet.Metadata().Timestamp
if firstPacketTime.IsZero() {
firstPacketTime = timestamp
}
tcp := packet.TransportLayer().(*layers.TCP)
var servicePort, index int
if packet.NetworkLayer().NetworkFlow().Dst() == pi.serverIp {
servicePort, _ = strconv.Atoi(tcp.DstPort.String())
index = 0
} else {
servicePort, _ = strconv.Atoi(tcp.SrcPort.String())
index = 1
}
fCount, ok := packetsPerService[servicePort]
if !ok {
fCount = &flowCount{0, 0}
packetsPerService[servicePort] = fCount
}
fCount[index]++
assembler.AssembleWithTimestamp(packet.NetworkLayer().NetworkFlow(), tcp, timestamp)
case <-updateProgressInterval:
progressUpdate(false, nil)
}
}
}
func (pi *PcapImporter) takeAssembler() *tcpassembly.Assembler {
pi.mAssemblers.Lock()
defer pi.mAssemblers.Unlock()
if len(pi.assemblers) == 0 {
return tcpassembly.NewAssembler(pi.streamPool)
}
index := len(pi.assemblers) - 1
assembler := pi.assemblers[index]
pi.assemblers = pi.assemblers[:index]
return assembler
}
func (pi *PcapImporter) releaseAssembler(assembler *tcpassembly.Assembler) {
pi.mAssemblers.Lock()
pi.assemblers = append(pi.assemblers, assembler)
pi.mAssemblers.Unlock()
}
|
