source: code/trunk/vendor/nhooyr.io/websocket/frame.go@ 822

Last change on this file since 822 was 822, checked in by yakumo.izuru, 22 months ago

Prefer immortal.run over runit and rc.d, use vendored modules
for convenience.

Signed-off-by: Izuru Yakumo <yakumo.izuru@…>
File size: 7.4 KB
RevLine 
[822]1package websocket
2
3import (
4 "bufio"
5 "encoding/binary"
6 "fmt"
7 "io"
8 "math"
9 "math/bits"
10
11 "nhooyr.io/websocket/internal/errd"
12)
13
14// opcode represents a WebSocket opcode.
15type opcode int
16
17// https://tools.ietf.org/html/rfc6455#section-11.8.
18const (
19 opContinuation opcode = iota
20 opText
21 opBinary
22 // 3 - 7 are reserved for further non-control frames.
23 _
24 _
25 _
26 _
27 _
28 opClose
29 opPing
30 opPong
31 // 11-16 are reserved for further control frames.
32)
33
34// header represents a WebSocket frame header.
35// See https://tools.ietf.org/html/rfc6455#section-5.2.
36type header struct {
37 fin bool
38 rsv1 bool
39 rsv2 bool
40 rsv3 bool
41 opcode opcode
42
43 payloadLength int64
44
45 masked bool
46 maskKey uint32
47}
48
49// readFrameHeader reads a header from the reader.
50// See https://tools.ietf.org/html/rfc6455#section-5.2.
51func readFrameHeader(r *bufio.Reader, readBuf []byte) (h header, err error) {
52 defer errd.Wrap(&err, "failed to read frame header")
53
54 b, err := r.ReadByte()
55 if err != nil {
56 return header{}, err
57 }
58
59 h.fin = b&(1<<7) != 0
60 h.rsv1 = b&(1<<6) != 0
61 h.rsv2 = b&(1<<5) != 0
62 h.rsv3 = b&(1<<4) != 0
63
64 h.opcode = opcode(b & 0xf)
65
66 b, err = r.ReadByte()
67 if err != nil {
68 return header{}, err
69 }
70
71 h.masked = b&(1<<7) != 0
72
73 payloadLength := b &^ (1 << 7)
74 switch {
75 case payloadLength < 126:
76 h.payloadLength = int64(payloadLength)
77 case payloadLength == 126:
78 _, err = io.ReadFull(r, readBuf[:2])
79 h.payloadLength = int64(binary.BigEndian.Uint16(readBuf))
80 case payloadLength == 127:
81 _, err = io.ReadFull(r, readBuf)
82 h.payloadLength = int64(binary.BigEndian.Uint64(readBuf))
83 }
84 if err != nil {
85 return header{}, err
86 }
87
88 if h.payloadLength < 0 {
89 return header{}, fmt.Errorf("received negative payload length: %v", h.payloadLength)
90 }
91
92 if h.masked {
93 _, err = io.ReadFull(r, readBuf[:4])
94 if err != nil {
95 return header{}, err
96 }
97 h.maskKey = binary.LittleEndian.Uint32(readBuf)
98 }
99
100 return h, nil
101}
102
103// maxControlPayload is the maximum length of a control frame payload.
104// See https://tools.ietf.org/html/rfc6455#section-5.5.
105const maxControlPayload = 125
106
107// writeFrameHeader writes the bytes of the header to w.
108// See https://tools.ietf.org/html/rfc6455#section-5.2
109func writeFrameHeader(h header, w *bufio.Writer, buf []byte) (err error) {
110 defer errd.Wrap(&err, "failed to write frame header")
111
112 var b byte
113 if h.fin {
114 b |= 1 << 7
115 }
116 if h.rsv1 {
117 b |= 1 << 6
118 }
119 if h.rsv2 {
120 b |= 1 << 5
121 }
122 if h.rsv3 {
123 b |= 1 << 4
124 }
125
126 b |= byte(h.opcode)
127
128 err = w.WriteByte(b)
129 if err != nil {
130 return err
131 }
132
133 lengthByte := byte(0)
134 if h.masked {
135 lengthByte |= 1 << 7
136 }
137
138 switch {
139 case h.payloadLength > math.MaxUint16:
140 lengthByte |= 127
141 case h.payloadLength > 125:
142 lengthByte |= 126
143 case h.payloadLength >= 0:
144 lengthByte |= byte(h.payloadLength)
145 }
146 err = w.WriteByte(lengthByte)
147 if err != nil {
148 return err
149 }
150
151 switch {
152 case h.payloadLength > math.MaxUint16:
153 binary.BigEndian.PutUint64(buf, uint64(h.payloadLength))
154 _, err = w.Write(buf)
155 case h.payloadLength > 125:
156 binary.BigEndian.PutUint16(buf, uint16(h.payloadLength))
157 _, err = w.Write(buf[:2])
158 }
159 if err != nil {
160 return err
161 }
162
163 if h.masked {
164 binary.LittleEndian.PutUint32(buf, h.maskKey)
165 _, err = w.Write(buf[:4])
166 if err != nil {
167 return err
168 }
169 }
170
171 return nil
172}
173
174// mask applies the WebSocket masking algorithm to p
175// with the given key.
176// See https://tools.ietf.org/html/rfc6455#section-5.3
177//
178// The returned value is the correctly rotated key to
179// to continue to mask/unmask the message.
180//
181// It is optimized for LittleEndian and expects the key
182// to be in little endian.
183//
184// See https://github.com/golang/go/issues/31586
185func mask(key uint32, b []byte) uint32 {
186 if len(b) >= 8 {
187 key64 := uint64(key)<<32 | uint64(key)
188
189 // At some point in the future we can clean these unrolled loops up.
190 // See https://github.com/golang/go/issues/31586#issuecomment-487436401
191
192 // Then we xor until b is less than 128 bytes.
193 for len(b) >= 128 {
194 v := binary.LittleEndian.Uint64(b)
195 binary.LittleEndian.PutUint64(b, v^key64)
196 v = binary.LittleEndian.Uint64(b[8:16])
197 binary.LittleEndian.PutUint64(b[8:16], v^key64)
198 v = binary.LittleEndian.Uint64(b[16:24])
199 binary.LittleEndian.PutUint64(b[16:24], v^key64)
200 v = binary.LittleEndian.Uint64(b[24:32])
201 binary.LittleEndian.PutUint64(b[24:32], v^key64)
202 v = binary.LittleEndian.Uint64(b[32:40])
203 binary.LittleEndian.PutUint64(b[32:40], v^key64)
204 v = binary.LittleEndian.Uint64(b[40:48])
205 binary.LittleEndian.PutUint64(b[40:48], v^key64)
206 v = binary.LittleEndian.Uint64(b[48:56])
207 binary.LittleEndian.PutUint64(b[48:56], v^key64)
208 v = binary.LittleEndian.Uint64(b[56:64])
209 binary.LittleEndian.PutUint64(b[56:64], v^key64)
210 v = binary.LittleEndian.Uint64(b[64:72])
211 binary.LittleEndian.PutUint64(b[64:72], v^key64)
212 v = binary.LittleEndian.Uint64(b[72:80])
213 binary.LittleEndian.PutUint64(b[72:80], v^key64)
214 v = binary.LittleEndian.Uint64(b[80:88])
215 binary.LittleEndian.PutUint64(b[80:88], v^key64)
216 v = binary.LittleEndian.Uint64(b[88:96])
217 binary.LittleEndian.PutUint64(b[88:96], v^key64)
218 v = binary.LittleEndian.Uint64(b[96:104])
219 binary.LittleEndian.PutUint64(b[96:104], v^key64)
220 v = binary.LittleEndian.Uint64(b[104:112])
221 binary.LittleEndian.PutUint64(b[104:112], v^key64)
222 v = binary.LittleEndian.Uint64(b[112:120])
223 binary.LittleEndian.PutUint64(b[112:120], v^key64)
224 v = binary.LittleEndian.Uint64(b[120:128])
225 binary.LittleEndian.PutUint64(b[120:128], v^key64)
226 b = b[128:]
227 }
228
229 // Then we xor until b is less than 64 bytes.
230 for len(b) >= 64 {
231 v := binary.LittleEndian.Uint64(b)
232 binary.LittleEndian.PutUint64(b, v^key64)
233 v = binary.LittleEndian.Uint64(b[8:16])
234 binary.LittleEndian.PutUint64(b[8:16], v^key64)
235 v = binary.LittleEndian.Uint64(b[16:24])
236 binary.LittleEndian.PutUint64(b[16:24], v^key64)
237 v = binary.LittleEndian.Uint64(b[24:32])
238 binary.LittleEndian.PutUint64(b[24:32], v^key64)
239 v = binary.LittleEndian.Uint64(b[32:40])
240 binary.LittleEndian.PutUint64(b[32:40], v^key64)
241 v = binary.LittleEndian.Uint64(b[40:48])
242 binary.LittleEndian.PutUint64(b[40:48], v^key64)
243 v = binary.LittleEndian.Uint64(b[48:56])
244 binary.LittleEndian.PutUint64(b[48:56], v^key64)
245 v = binary.LittleEndian.Uint64(b[56:64])
246 binary.LittleEndian.PutUint64(b[56:64], v^key64)
247 b = b[64:]
248 }
249
250 // Then we xor until b is less than 32 bytes.
251 for len(b) >= 32 {
252 v := binary.LittleEndian.Uint64(b)
253 binary.LittleEndian.PutUint64(b, v^key64)
254 v = binary.LittleEndian.Uint64(b[8:16])
255 binary.LittleEndian.PutUint64(b[8:16], v^key64)
256 v = binary.LittleEndian.Uint64(b[16:24])
257 binary.LittleEndian.PutUint64(b[16:24], v^key64)
258 v = binary.LittleEndian.Uint64(b[24:32])
259 binary.LittleEndian.PutUint64(b[24:32], v^key64)
260 b = b[32:]
261 }
262
263 // Then we xor until b is less than 16 bytes.
264 for len(b) >= 16 {
265 v := binary.LittleEndian.Uint64(b)
266 binary.LittleEndian.PutUint64(b, v^key64)
267 v = binary.LittleEndian.Uint64(b[8:16])
268 binary.LittleEndian.PutUint64(b[8:16], v^key64)
269 b = b[16:]
270 }
271
272 // Then we xor until b is less than 8 bytes.
273 for len(b) >= 8 {
274 v := binary.LittleEndian.Uint64(b)
275 binary.LittleEndian.PutUint64(b, v^key64)
276 b = b[8:]
277 }
278 }
279
280 // Then we xor until b is less than 4 bytes.
281 for len(b) >= 4 {
282 v := binary.LittleEndian.Uint32(b)
283 binary.LittleEndian.PutUint32(b, v^key)
284 b = b[4:]
285 }
286
287 // xor remaining bytes.
288 for i := range b {
289 b[i] ^= byte(key)
290 key = bits.RotateLeft32(key, -8)
291 }
292
293 return key
294}
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