// 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" ) 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 += 1 case b == '\\': escape = true case b == '"': return string(p[:j]), s[i+1:] default: p[j] = b j += 1 } } return "", "" } } return "", "" } // tokenListContainsValue returns true if the 1#token header with the given // name contains token. 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 strings.EqualFold(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 }