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
|
// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package websocket
import (
"crypto/rand"
"crypto/sha1"
"encoding/base64"
"io"
"net/http"
"strings"
"unicode/utf8"
)
var keyGUID = []byte("258EAFA5-E914-47DA-95CA-C5AB0DC85B11")
func computeAcceptKey(challengeKey string) string {
h := sha1.New()
h.Write([]byte(challengeKey))
h.Write(keyGUID)
return base64.StdEncoding.EncodeToString(h.Sum(nil))
}
func generateChallengeKey() (string, error) {
p := make([]byte, 16)
if _, err := io.ReadFull(rand.Reader, p); err != nil {
return "", err
}
return base64.StdEncoding.EncodeToString(p), nil
}
// Octet types from RFC 2616.
var octetTypes [256]byte
const (
isTokenOctet = 1 << iota
isSpaceOctet
)
func init() {
// From RFC 2616
//
// OCTET = <any 8-bit sequence of data>
// CHAR = <any US-ASCII character (octets 0 - 127)>
// CTL = <any US-ASCII control character (octets 0 - 31) and DEL (127)>
// CR = <US-ASCII CR, carriage return (13)>
// LF = <US-ASCII LF, linefeed (10)>
// SP = <US-ASCII SP, space (32)>
// HT = <US-ASCII HT, horizontal-tab (9)>
// <"> = <US-ASCII double-quote mark (34)>
// CRLF = CR LF
// LWS = [CRLF] 1*( SP | HT )
// TEXT = <any OCTET except CTLs, but including LWS>
// separators = "(" | ")" | "<" | ">" | "@" | "," | ";" | ":" | "\" | <">
// | "/" | "[" | "]" | "?" | "=" | "{" | "}" | SP | HT
// token = 1*<any CHAR except CTLs or separators>
// qdtext = <any TEXT except <">>
for c := 0; c < 256; c++ {
var t byte
isCtl := c <= 31 || c == 127
isChar := 0 <= c && c <= 127
isSeparator := strings.IndexRune(" \t\"(),/:;<=>?@[]\\{}", rune(c)) >= 0
if strings.IndexRune(" \t\r\n", rune(c)) >= 0 {
t |= isSpaceOctet
}
if isChar && !isCtl && !isSeparator {
t |= isTokenOctet
}
octetTypes[c] = t
}
}
func skipSpace(s string) (rest string) {
i := 0
for ; i < len(s); i++ {
if octetTypes[s[i]]&isSpaceOctet == 0 {
break
}
}
return s[i:]
}
func nextToken(s string) (token, rest string) {
i := 0
for ; i < len(s); i++ {
if octetTypes[s[i]]&isTokenOctet == 0 {
break
}
}
return s[:i], s[i:]
}
func nextTokenOrQuoted(s string) (value string, rest string) {
if !strings.HasPrefix(s, "\"") {
return nextToken(s)
}
s = s[1:]
for i := 0; i < len(s); i++ {
switch s[i] {
case '"':
return s[:i], s[i+1:]
case '\\':
p := make([]byte, len(s)-1)
j := copy(p, s[:i])
escape := true
for i = i + 1; i < len(s); i++ {
b := s[i]
switch {
case escape:
escape = false
p[j] = b
j++
case b == '\\':
escape = true
case b == '"':
return string(p[:j]), s[i+1:]
default:
p[j] = b
j++
}
}
return "", ""
}
}
return "", ""
}
// equalASCIIFold returns true if s is equal to t with ASCII case folding.
func equalASCIIFold(s, t string) bool {
for s != "" && t != "" {
sr, size := utf8.DecodeRuneInString(s)
s = s[size:]
tr, size := utf8.DecodeRuneInString(t)
t = t[size:]
if sr == tr {
continue
}
if 'A' <= sr && sr <= 'Z' {
sr = sr + 'a' - 'A'
}
if 'A' <= tr && tr <= 'Z' {
tr = tr + 'a' - 'A'
}
if sr != tr {
return false
}
}
return s == t
}
// tokenListContainsValue returns true if the 1#token header with the given
// name contains a token equal to value with ASCII case folding.
func tokenListContainsValue(header http.Header, name string, value string) bool {
headers:
for _, s := range header[name] {
for {
var t string
t, s = nextToken(skipSpace(s))
if t == "" {
continue headers
}
s = skipSpace(s)
if s != "" && s[0] != ',' {
continue headers
}
if equalASCIIFold(t, value) {
return true
}
if s == "" {
continue headers
}
s = s[1:]
}
}
return false
}
// parseExtensiosn parses WebSocket extensions from a header.
func parseExtensions(header http.Header) []map[string]string {
// From RFC 6455:
//
// Sec-WebSocket-Extensions = extension-list
// extension-list = 1#extension
// extension = extension-token *( ";" extension-param )
// extension-token = registered-token
// registered-token = token
// extension-param = token [ "=" (token | quoted-string) ]
// ;When using the quoted-string syntax variant, the value
// ;after quoted-string unescaping MUST conform to the
// ;'token' ABNF.
var result []map[string]string
headers:
for _, s := range header["Sec-Websocket-Extensions"] {
for {
var t string
t, s = nextToken(skipSpace(s))
if t == "" {
continue headers
}
ext := map[string]string{"": t}
for {
s = skipSpace(s)
if !strings.HasPrefix(s, ";") {
break
}
var k string
k, s = nextToken(skipSpace(s[1:]))
if k == "" {
continue headers
}
s = skipSpace(s)
var v string
if strings.HasPrefix(s, "=") {
v, s = nextTokenOrQuoted(skipSpace(s[1:]))
s = skipSpace(s)
}
if s != "" && s[0] != ',' && s[0] != ';' {
continue headers
}
ext[k] = v
}
if s != "" && s[0] != ',' {
continue headers
}
result = append(result, ext)
if s == "" {
continue headers
}
s = s[1:]
}
}
return result
}
|
