-
Notifications
You must be signed in to change notification settings - Fork 4.5k
/
client_session.go
292 lines (252 loc) · 7.4 KB
/
client_session.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
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
package shadowsocks2022
import (
"context"
"crypto/rand"
"io"
gonet "net"
"sync"
"time"
"github.com/v2fly/v2ray-core/v5/common/buf"
"github.com/v2fly/v2ray-core/v5/common/net"
"github.com/v2fly/v2ray-core/v5/transport/internet"
"github.com/pion/transport/v2/replaydetector"
)
func NewClientUDPSession(ctx context.Context, conn io.ReadWriteCloser, packetProcessor UDPClientPacketProcessor) *ClientUDPSession {
session := &ClientUDPSession{
locker: &sync.RWMutex{},
conn: conn,
packetProcessor: packetProcessor,
sessionMap: make(map[string]*ClientUDPSessionConn),
sessionMapAlias: make(map[string]string),
}
session.ctx, session.finish = context.WithCancel(ctx)
go session.KeepReading()
return session
}
type ClientUDPSession struct {
locker *sync.RWMutex
conn io.ReadWriteCloser
packetProcessor UDPClientPacketProcessor
sessionMap map[string]*ClientUDPSessionConn
sessionMapAlias map[string]string
ctx context.Context
finish func()
}
func (c *ClientUDPSession) GetCachedState(sessionID string) UDPClientPacketProcessorCachedState {
c.locker.RLock()
defer c.locker.RUnlock()
state, ok := c.sessionMap[sessionID]
if !ok {
return nil
}
return state.cachedProcessorState
}
func (c *ClientUDPSession) GetCachedServerState(serverSessionID string) UDPClientPacketProcessorCachedState {
c.locker.RLock()
defer c.locker.RUnlock()
clientSessionID := c.getCachedStateAlias(serverSessionID)
if clientSessionID == "" {
return nil
}
state, ok := c.sessionMap[clientSessionID]
if !ok {
return nil
}
if serverState, ok := state.trackedServerSessionID[serverSessionID]; !ok {
return nil
} else {
return serverState.cachedRecvProcessorState
}
}
func (c *ClientUDPSession) getCachedStateAlias(serverSessionID string) string {
state, ok := c.sessionMapAlias[serverSessionID]
if !ok {
return ""
}
return state
}
func (c *ClientUDPSession) PutCachedState(sessionID string, cache UDPClientPacketProcessorCachedState) {
c.locker.RLock()
defer c.locker.RUnlock()
state, ok := c.sessionMap[sessionID]
if !ok {
return
}
state.cachedProcessorState = cache
}
func (c *ClientUDPSession) PutCachedServerState(serverSessionID string, cache UDPClientPacketProcessorCachedState) {
c.locker.RLock()
defer c.locker.RUnlock()
clientSessionID := c.getCachedStateAlias(serverSessionID)
if clientSessionID == "" {
return
}
state, ok := c.sessionMap[clientSessionID]
if !ok {
return
}
if serverState, ok := state.trackedServerSessionID[serverSessionID]; ok {
serverState.cachedRecvProcessorState = cache
return
}
}
func (c *ClientUDPSession) Close() error {
c.finish()
return c.conn.Close()
}
func (c *ClientUDPSession) WriteUDPRequest(request *UDPRequest) error {
buffer := buf.New()
defer buffer.Release()
err := c.packetProcessor.EncodeUDPRequest(request, buffer, c)
if request.Payload != nil {
request.Payload.Release()
}
if err != nil {
return newError("unable to encode udp request").Base(err)
}
_, err = c.conn.Write(buffer.Bytes())
if err != nil {
return newError("unable to write to conn").Base(err)
}
return nil
}
func (c *ClientUDPSession) KeepReading() {
for c.ctx.Err() == nil {
udpResp := &UDPResponse{}
buffer := make([]byte, 1600)
n, err := c.conn.Read(buffer)
if err != nil {
newError("unable to read from conn").Base(err).WriteToLog()
return
}
if n != 0 {
err := c.packetProcessor.DecodeUDPResp(buffer[:n], udpResp, c)
if err != nil {
newError("unable to decode udp response").Base(err).WriteToLog()
continue
}
{
timeDifference := int64(udpResp.TimeStamp) - time.Now().Unix()
if timeDifference < -30 || timeDifference > 30 {
newError("udp packet timestamp difference too large, packet discarded, time diff = ", timeDifference).WriteToLog()
continue
}
}
c.locker.RLock()
session, ok := c.sessionMap[string(udpResp.ClientSessionID[:])]
c.locker.RUnlock()
if ok {
select {
case session.readChan <- udpResp:
default:
}
} else {
newError("misbehaving server: unknown client session ID").Base(err).WriteToLog()
}
}
}
}
func (c *ClientUDPSession) NewSessionConn() (internet.AbstractPacketConn, error) {
sessionID := make([]byte, 8)
_, err := rand.Read(sessionID)
if err != nil {
return nil, newError("unable to generate session id").Base(err)
}
connctx, connfinish := context.WithCancel(c.ctx)
sessionConn := &ClientUDPSessionConn{
sessionID: string(sessionID),
readChan: make(chan *UDPResponse, 128),
parent: c,
ctx: connctx,
finish: connfinish,
nextWritePacketID: 0,
trackedServerSessionID: make(map[string]*ClientUDPSessionServerTracker),
}
c.locker.Lock()
c.sessionMap[sessionConn.sessionID] = sessionConn
c.locker.Unlock()
return sessionConn, nil
}
type ClientUDPSessionServerTracker struct {
cachedRecvProcessorState UDPClientPacketProcessorCachedState
rxReplayDetector replaydetector.ReplayDetector
lastSeen time.Time
}
type ClientUDPSessionConn struct {
sessionID string
readChan chan *UDPResponse
parent *ClientUDPSession
nextWritePacketID uint64
trackedServerSessionID map[string]*ClientUDPSessionServerTracker
cachedProcessorState UDPClientPacketProcessorCachedState
ctx context.Context
finish func()
}
func (c *ClientUDPSessionConn) Close() error {
c.parent.locker.Lock()
delete(c.parent.sessionMap, c.sessionID)
for k := range c.trackedServerSessionID {
delete(c.parent.sessionMapAlias, k)
}
c.parent.locker.Unlock()
c.finish()
return nil
}
func (c *ClientUDPSessionConn) WriteTo(p []byte, addr gonet.Addr) (n int, err error) {
thisPacketID := c.nextWritePacketID
c.nextWritePacketID += 1
req := &UDPRequest{
SessionID: [8]byte{},
PacketID: thisPacketID,
TimeStamp: uint64(time.Now().Unix()),
Address: net.IPAddress(addr.(*gonet.UDPAddr).IP),
Port: addr.(*net.UDPAddr).Port,
Payload: nil,
}
copy(req.SessionID[:], c.sessionID)
req.Payload = buf.New()
req.Payload.Write(p)
err = c.parent.WriteUDPRequest(req)
if err != nil {
return 0, newError("unable to write to parent session").Base(err)
}
return len(p), nil
}
func (c *ClientUDPSessionConn) ReadFrom(p []byte) (n int, addr net.Addr, err error) {
for {
select {
case <-c.ctx.Done():
return 0, nil, io.EOF
case resp := <-c.readChan:
n = copy(p, resp.Payload.Bytes())
resp.Payload.Release()
var trackedState *ClientUDPSessionServerTracker
if trackedStateReceived, ok := c.trackedServerSessionID[string(resp.SessionID[:])]; !ok {
for key, value := range c.trackedServerSessionID {
if time.Since(value.lastSeen) > 65*time.Second {
delete(c.trackedServerSessionID, key)
}
}
state := &ClientUDPSessionServerTracker{
rxReplayDetector: replaydetector.New(1024, ^uint64(0)),
}
c.trackedServerSessionID[string(resp.SessionID[:])] = state
c.parent.locker.RLock()
c.parent.sessionMapAlias[string(resp.SessionID[:])] = string(resp.ClientSessionID[:])
c.parent.locker.RUnlock()
trackedState = state
} else {
trackedState = trackedStateReceived
}
if accept, ok := trackedState.rxReplayDetector.Check(resp.PacketID); ok {
accept()
} else {
newError("misbehaving server: replayed packet").Base(err).WriteToLog()
continue
}
trackedState.lastSeen = time.Now()
addr = &net.UDPAddr{IP: resp.Address.IP(), Port: resp.Port}
}
return n, addr, nil
}
}