-
Notifications
You must be signed in to change notification settings - Fork 5
/
tcp.go
277 lines (240 loc) · 7.84 KB
/
tcp.go
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
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
/**
* @Author: kiosk
* @Mail: weijiaxiang007@foxmail.com
* @Date: 2020/12/27
**/
package packet
import (
"fmt"
"github.com/google/gopacket"
"github.com/google/gopacket/layers"
"github.com/google/gopacket/reassembly"
"sync"
"github.com/kiosk404/tls-decrypt/tls"
"github.com/kiosk404/tls-decrypt/tls/tlsx"
"github.com/kiosk404/tls-decrypt/utils"
)
/*
*
* TCP stream
*/
/* It's a connection (bidirectional) */
type TcpStream struct {
tcpstate *reassembly.TCPSimpleFSM
optchecker reassembly.TCPOptionCheck
net, transport gopacket.Flow
urls []string
ident string
fsmerr bool
sync.Mutex
isHTTP bool
httpReversed bool
isHTTPS bool
httpsReversed bool
httpClient HttpReader
httpServer HttpReader
isDecrypt bool
decryptReversed bool
decryptPort int
tlsClient TLSReader
tlsServer TLSReader
tlsStream *tls.TLSStream // tmp
clientWindowScale int // 次数统计
serverWindowScale int
clientRetransmission int
serverRetransmission int
clientZeroWindow int
serverFullWindow int
clientKeepAlive int
serverKeepAlive int
clientReset int
serverReset int
}
/*
* The TCP factory: returns a new Stream
*/
type TcpStreamFactory struct {
WG sync.WaitGroup
doHTTP, doDecrypt, hexdump bool
decryptPort layers.TCPPort
output string
}
func (factory *TcpStreamFactory) WaitGoRoutines() {
factory.WG.Wait()
}
func (factory TcpStreamFactory) New(netFlow, transport gopacket.Flow, tcp *layers.TCP, ac reassembly.AssemblerContext) reassembly.Stream {
utils.Logging.Debug().Msgf("* NEW: %s %s\n", netFlow, transport)
fsmOptions := reassembly.TCPSimpleFSMOptions{
SupportMissingEstablishment: true,
}
stream := &TcpStream{
net: netFlow,
transport: transport,
isHTTP: (tcp.SrcPort == 80 || tcp.DstPort == 80) && factory.doHTTP,
httpReversed: tcp.SrcPort == 80,
isHTTPS: (tcp.SrcPort == 443 || tcp.DstPort == 443) && factory.doHTTP,
httpsReversed: tcp.SrcPort == 443,
isDecrypt : (tcp.SrcPort == factory.decryptPort || tcp.DstPort == factory.decryptPort) && factory.doDecrypt,
decryptReversed: tcp.SrcPort == factory.decryptPort,
tlsStream: tls.NewTLSStream(),
tcpstate: reassembly.NewTCPSimpleFSM(fsmOptions), // 不记录缺少 SYN 的流
ident: fmt.Sprintf("%s:%s", netFlow, transport), // 例如 10.2.203.95->122.14.230.144:54367->2018
optchecker: reassembly.NewTCPOptionCheck(), // 创建一个默认的 Option ,内容有 mss ,scale, receiveWindow
clientRetransmission: 0,
serverRetransmission: 0,
clientReset: 0,
serverReset: 0,
}
factoryWG := 0
if stream.isHTTP || stream.isHTTPS{
factoryWG ++
stream.httpClient = NewHTTPReader(stream,netFlow, transport,true,factory.hexdump)
stream.httpServer = NewHTTPReader(stream,netFlow.Reverse(),transport.Reverse(),false,factory.hexdump)
}
if stream.isDecrypt {
factoryWG ++
stream.tlsClient = NewTLSReader(stream, netFlow, transport, true, factory.hexdump, stream.tlsStream)
stream.tlsServer = NewTLSReader(stream, netFlow.Reverse(), transport.Reverse(), false, factory.hexdump, stream.tlsStream)
}
factory.WG.Add(factoryWG)
if stream.isHTTP || stream.isHTTPS {
go stream.httpClient.run(&factory.WG)
go stream.httpServer.run(&factory.WG)
}
if stream.isDecrypt {
go stream.tlsClient.run(&factory.WG)
go stream.tlsServer.run(&factory.WG)
}
return stream
}
func (t *TcpStream) Accept(tcp *layers.TCP, ci gopacket.CaptureInfo, dir reassembly.TCPFlowDirection, nextSeq reassembly.Sequence, start *bool, ac reassembly.AssemblerContext) bool {
length := len(tcp.Payload)
if nextSeq != -1 {
diff := nextSeq.Difference(reassembly.Sequence(tcp.Seq))
if reassembly.TCPDirClientToServer == dir {
if diff == -1 && (length == 1 || length == 0) {
// This is probably a Keep-alive
// TODO: check byte is ok
} else if diff < 0 {
t.clientRetransmission ++
}
}else {
if diff == -1 && (length == 1 || length == 0) {
// This is probably a Keep-alive
// TODO: check byte is ok
} else if diff < 0 {
t.serverRetransmission ++
}
}
}
// FSM
if !t.tcpstate.CheckState(tcp, dir) {
utils.Logging.Error().Msgf("FSM", "%s: Packet rejected by FSM (state:%s)\n", t.ident, t.tcpstate.String())
Stats.rejectFsm++
if !t.fsmerr {
t.fsmerr = true
Stats.rejectConnFsm++
}
}
// Options
err := t.optchecker.Accept(tcp, ci, dir, nextSeq, start)
if err != nil {
utils.Logging.Error().Msgf("OptionChecker", "%s: Packet rejected by OptionChecker: %s\n", t.ident, err)
Stats.rejectOpt++
}
return true
}
func (t *TcpStream) ReassembledSG(sg reassembly.ScatterGather, ac reassembly.AssemblerContext) {
dir, start, end, skip := sg.Info() // client->server, false, false, 0
length, saved := sg.Lengths()
// update stats
sgStats := sg.Stats()
if skip > 0 {
Stats.missedBytes += skip // 没有捕捉到的字节数
}
Stats.sz += length - saved
Stats.pkt += sgStats.Packets // 数据包的个数
if sgStats.Chunks > 1 { // 只要是有负载的数据包,非纯ACK的包都有 sgStats 属性 (三次握手和四次挥手除外)
Stats.reassembled++
}
Stats.outOfOrderPackets += sgStats.QueuedPackets // 乱序包数
Stats.outOfOrderBytes += sgStats.QueuedBytes // 乱序字节
if length > Stats.biggestChunkBytes {
Stats.biggestChunkBytes = length // 所传的最大一个包的所带的字节数
}
if sgStats.Packets > Stats.biggestChunkPackets { // 数据包个数
Stats.biggestChunkPackets = sgStats.Packets
}
if sgStats.OverlapBytes != 0 && sgStats.OverlapPackets == 0 {
fmt.Printf("bytes:%d, pkts:%d\n", sgStats.OverlapBytes, sgStats.OverlapPackets)
panic("Invalid overlap")
}
Stats.overlapBytes += sgStats.OverlapBytes
Stats.overlapPackets += sgStats.OverlapPackets
var ident string
if dir == reassembly.TCPDirClientToServer {
ident = fmt.Sprintf("%v %v(%s): ", t.net, t.transport, dir)
} else {
ident = fmt.Sprintf("%v %v(%s): ", t.net.Reverse(), t.transport.Reverse(), dir)
}
utils.Logging.Debug().Msgf("%s: SG reassembled packet with %d bytes (start:%v,end:%v,skip:%d,saved:%d,nb:%d,%d,overlap:%d,%d)\n", ident, length, start, end, skip, saved, sgStats.Packets, sgStats.Chunks, sgStats.OverlapBytes, sgStats.OverlapPackets)
data := sg.Fetch(length)
//
if t.isHTTP {
if length > 0 {
if dir == reassembly.TCPDirClientToServer && !t.httpReversed {
t.httpClient.bytes <- data
} else {
t.httpServer.bytes <- data
}
}
}
if t.isDecrypt {
if length > 0 {
var got layers.TLS
err := got.DecodeFromBytes(data, gopacket.NilDecodeFeedback)
if dir == reassembly.TCPDirClientToServer && !t.decryptReversed {
TLSType := uint8(data[0])
utils.Logging.Info().Uint8("TLS TYPE",TLSType)
switch TLSType {
case tlsx.TLSHandShake:
err = t.tlsStream.UnmarshalHandshake(data, tls.ClientHello)
if err != nil {
utils.Logging.Error().Err(err).Msg("client handshake unmarshal fail")
}
case tlsx.TLSApplication:
t.tlsClient.bytes <- data
default:
fmt.Println("Unknown TLS type ", TLSType)
}
} else {
TLSType := uint8(data[0])
switch TLSType {
case tlsx.TLSHandShake:
err = t.tlsStream.UnmarshalHandshake(data, tls.ServerHello)
if err != nil {
utils.Logging.Error().Err(err).Msg("server handshake unmarshal fail")
}
_ = t.tlsStream.EstablishConn()
case tlsx.TLSApplication:
t.tlsServer.bytes <- data
default:
fmt.Println("Unknown TLS type ", TLSType)
}
}
}
}
}
func (t *TcpStream) ReassemblyComplete(ac reassembly.AssemblerContext) bool {
utils.Logging.Debug().Msgf("%s: Connection closed\n", t.ident)
if t.isHTTP || t.isHTTPS {
close(t.httpClient.bytes)
close(t.httpServer.bytes)
}
if t.isDecrypt {
close(t.tlsClient.bytes)
close(t.tlsServer.bytes)
}
// do not remove the connection to allow last ACK
return false
}