-
Notifications
You must be signed in to change notification settings - Fork 47
/
conn.go
389 lines (329 loc) · 9.14 KB
/
conn.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
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
// SPDX-License-Identifier: MIT
// Package udp provides a connection-oriented listener over a UDP PacketConn
package udp
import (
"context"
"errors"
"net"
"sync"
"sync/atomic"
"time"
"github.com/pion/transport/v2/deadline"
"github.com/pion/transport/v2/packetio"
"golang.org/x/net/ipv4"
)
const (
receiveMTU = 8192
sendMTU = 1500
defaultListenBacklog = 128 // same as Linux default
)
// Typed errors
var (
ErrClosedListener = errors.New("udp: listener closed")
ErrListenQueueExceeded = errors.New("udp: listen queue exceeded")
ErrInvalidBatchConfig = errors.New("udp: invalid batch config")
)
// listener augments a connection-oriented Listener over a UDP PacketConn
type listener struct {
pConn net.PacketConn
readBatchSize int
accepting atomic.Value // bool
acceptCh chan *Conn
doneCh chan struct{}
doneOnce sync.Once
acceptFilter func([]byte) bool
connLock sync.Mutex
conns map[string]*Conn
connWG *sync.WaitGroup
readWG sync.WaitGroup
errClose atomic.Value // error
readDoneCh chan struct{}
errRead atomic.Value // error
}
// Accept waits for and returns the next connection to the listener.
func (l *listener) Accept() (net.Conn, error) {
select {
case c := <-l.acceptCh:
l.connWG.Add(1)
return c, nil
case <-l.readDoneCh:
err, _ := l.errRead.Load().(error)
return nil, err
case <-l.doneCh:
return nil, ErrClosedListener
}
}
// Close closes the listener.
// Any blocked Accept operations will be unblocked and return errors.
func (l *listener) Close() error {
var err error
l.doneOnce.Do(func() {
l.accepting.Store(false)
close(l.doneCh)
l.connLock.Lock()
// Close unaccepted connections
lclose:
for {
select {
case c := <-l.acceptCh:
close(c.doneCh)
delete(l.conns, c.rAddr.String())
default:
break lclose
}
}
nConns := len(l.conns)
l.connLock.Unlock()
l.connWG.Done()
if nConns == 0 {
// Wait if this is the final connection
l.readWG.Wait()
if errClose, ok := l.errClose.Load().(error); ok {
err = errClose
}
} else {
err = nil
}
})
return err
}
// Addr returns the listener's network address.
func (l *listener) Addr() net.Addr {
return l.pConn.LocalAddr()
}
// BatchIOConfig indicates config to batch read/write packets,
// it will use ReadBatch/WriteBatch to improve throughput for UDP.
type BatchIOConfig struct {
Enable bool
// ReadBatchSize indicates the maximum number of packets to be read in one batch, a batch size less than 2 means
// disable read batch.
ReadBatchSize int
// WriteBatchSize indicates the maximum number of packets to be written in one batch
WriteBatchSize int
// WriteBatchInterval indicates the maximum interval to wait before writing packets in one batch
// small interval will reduce latency/jitter, but increase the io count.
WriteBatchInterval time.Duration
}
// ListenConfig stores options for listening to an address.
type ListenConfig struct {
// Backlog defines the maximum length of the queue of pending
// connections. It is equivalent of the backlog argument of
// POSIX listen function.
// If a connection request arrives when the queue is full,
// the request will be silently discarded, unlike TCP.
// Set zero to use default value 128 which is same as Linux default.
Backlog int
// AcceptFilter determines whether the new conn should be made for
// the incoming packet. If not set, any packet creates new conn.
AcceptFilter func([]byte) bool
// ReadBufferSize sets the size of the operating system's
// receive buffer associated with the listener.
ReadBufferSize int
// WriteBufferSize sets the size of the operating system's
// send buffer associated with the connection.
WriteBufferSize int
Batch BatchIOConfig
}
// Listen creates a new listener based on the ListenConfig.
func (lc *ListenConfig) Listen(network string, laddr *net.UDPAddr) (net.Listener, error) {
if lc.Backlog == 0 {
lc.Backlog = defaultListenBacklog
}
if lc.Batch.Enable && (lc.Batch.WriteBatchSize <= 0 || lc.Batch.WriteBatchInterval <= 0) {
return nil, ErrInvalidBatchConfig
}
conn, err := net.ListenUDP(network, laddr)
if err != nil {
return nil, err
}
if lc.ReadBufferSize > 0 {
_ = conn.SetReadBuffer(lc.ReadBufferSize)
}
if lc.WriteBufferSize > 0 {
_ = conn.SetWriteBuffer(lc.WriteBufferSize)
}
l := &listener{
pConn: conn,
acceptCh: make(chan *Conn, lc.Backlog),
conns: make(map[string]*Conn),
doneCh: make(chan struct{}),
acceptFilter: lc.AcceptFilter,
connWG: &sync.WaitGroup{},
readDoneCh: make(chan struct{}),
}
if lc.Batch.Enable {
l.pConn = NewBatchConn(conn, lc.Batch.WriteBatchSize, lc.Batch.WriteBatchInterval)
l.readBatchSize = lc.Batch.ReadBatchSize
}
l.accepting.Store(true)
l.connWG.Add(1)
l.readWG.Add(2) // wait readLoop and Close execution routine
go l.readLoop()
go func() {
l.connWG.Wait()
if err := l.pConn.Close(); err != nil {
l.errClose.Store(err)
}
l.readWG.Done()
}()
return l, nil
}
// Listen creates a new listener using default ListenConfig.
func Listen(network string, laddr *net.UDPAddr) (net.Listener, error) {
return (&ListenConfig{}).Listen(network, laddr)
}
// readLoop has to tasks:
// 1. Dispatching incoming packets to the correct Conn.
// It can therefore not be ended until all Conns are closed.
// 2. Creating a new Conn when receiving from a new remote.
func (l *listener) readLoop() {
defer l.readWG.Done()
defer close(l.readDoneCh)
if br, ok := l.pConn.(BatchReader); ok && l.readBatchSize > 1 {
l.readBatch(br)
} else {
l.read()
}
}
func (l *listener) readBatch(br BatchReader) {
msgs := make([]ipv4.Message, l.readBatchSize)
for i := range msgs {
msg := &msgs[i]
msg.Buffers = [][]byte{make([]byte, receiveMTU)}
msg.OOB = make([]byte, 40)
}
for {
n, err := br.ReadBatch(msgs, 0)
if err != nil {
l.errRead.Store(err)
return
}
for i := 0; i < n; i++ {
l.dispatchMsg(msgs[i].Addr, msgs[i].Buffers[0][:msgs[i].N])
}
}
}
func (l *listener) read() {
buf := make([]byte, receiveMTU)
for {
n, raddr, err := l.pConn.ReadFrom(buf)
if err != nil {
l.errRead.Store(err)
return
}
l.dispatchMsg(raddr, buf[:n])
}
}
func (l *listener) dispatchMsg(addr net.Addr, buf []byte) {
conn, ok, err := l.getConn(addr, buf)
if err != nil {
return
}
if ok {
_, _ = conn.buffer.Write(buf)
}
}
func (l *listener) getConn(raddr net.Addr, buf []byte) (*Conn, bool, error) {
l.connLock.Lock()
defer l.connLock.Unlock()
conn, ok := l.conns[raddr.String()]
if !ok {
if isAccepting, ok := l.accepting.Load().(bool); !isAccepting || !ok {
return nil, false, ErrClosedListener
}
if l.acceptFilter != nil {
if !l.acceptFilter(buf) {
return nil, false, nil
}
}
conn = l.newConn(raddr)
select {
case l.acceptCh <- conn:
l.conns[raddr.String()] = conn
default:
return nil, false, ErrListenQueueExceeded
}
}
return conn, true, nil
}
// Conn augments a connection-oriented connection over a UDP PacketConn
type Conn struct {
listener *listener
rAddr net.Addr
buffer *packetio.Buffer
doneCh chan struct{}
doneOnce sync.Once
writeDeadline *deadline.Deadline
}
func (l *listener) newConn(rAddr net.Addr) *Conn {
return &Conn{
listener: l,
rAddr: rAddr,
buffer: packetio.NewBuffer(),
doneCh: make(chan struct{}),
writeDeadline: deadline.New(),
}
}
// Read reads from c into p
func (c *Conn) Read(p []byte) (int, error) {
return c.buffer.Read(p)
}
// Write writes len(p) bytes from p to the DTLS connection
func (c *Conn) Write(p []byte) (n int, err error) {
select {
case <-c.writeDeadline.Done():
return 0, context.DeadlineExceeded
default:
}
return c.listener.pConn.WriteTo(p, c.rAddr)
}
// Close closes the conn and releases any Read calls
func (c *Conn) Close() error {
var err error
c.doneOnce.Do(func() {
c.listener.connWG.Done()
close(c.doneCh)
c.listener.connLock.Lock()
delete(c.listener.conns, c.rAddr.String())
nConns := len(c.listener.conns)
c.listener.connLock.Unlock()
if isAccepting, ok := c.listener.accepting.Load().(bool); nConns == 0 && !isAccepting && ok {
// Wait if this is the final connection
c.listener.readWG.Wait()
if errClose, ok := c.listener.errClose.Load().(error); ok {
err = errClose
}
} else {
err = nil
}
if errBuf := c.buffer.Close(); errBuf != nil && err == nil {
err = errBuf
}
})
return err
}
// LocalAddr implements net.Conn.LocalAddr
func (c *Conn) LocalAddr() net.Addr {
return c.listener.pConn.LocalAddr()
}
// RemoteAddr implements net.Conn.RemoteAddr
func (c *Conn) RemoteAddr() net.Addr {
return c.rAddr
}
// SetDeadline implements net.Conn.SetDeadline
func (c *Conn) SetDeadline(t time.Time) error {
c.writeDeadline.Set(t)
return c.SetReadDeadline(t)
}
// SetReadDeadline implements net.Conn.SetDeadline
func (c *Conn) SetReadDeadline(t time.Time) error {
return c.buffer.SetReadDeadline(t)
}
// SetWriteDeadline implements net.Conn.SetDeadline
func (c *Conn) SetWriteDeadline(t time.Time) error {
c.writeDeadline.Set(t)
// Write deadline of underlying connection should not be changed
// since the connection can be shared.
return nil
}