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websocket: implement new protocol
http://www.whatwg.org/specs/web-socket-protocol/ (draft of draft-hixie-thewebsocketprotocol-76) draft-hixie-thewebsocketprotocol-76 will introduce new handshake incompatible draft 75 or prior. http://tools.ietf.org/html/draft-hixie-thewebsocketprotocol R=rsc CC=golang-dev https://golang.org/cl/583041
This commit is contained in:
Fumitoshi Ukai
Russ Cox
parent
2ab9114dd7
commit
371496e0b8
3 changed files with 431 additions and 15 deletions
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@ -5,11 +5,18 @@
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package websocket
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import (
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"encoding/binary"
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"bufio"
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"bytes"
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"container/vector"
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"crypto/md5"
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"fmt"
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"http"
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"io"
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"net"
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"os"
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"rand"
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"strings"
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)
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type ProtocolError struct {
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@ -26,10 +33,26 @@ var (
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ErrBadWebSocketLocation = &ProtocolError{"bad WebSocket-Location"}
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ErrNoWebSocketProtocol = &ProtocolError{"no WebSocket-Protocol"}
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ErrBadWebSocketProtocol = &ProtocolError{"bad WebSocket-Protocol"}
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ErrChallengeResponse = &ProtocolError{"mismatch challange/response"}
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secKeyRandomChars [0x30 - 0x21 + 0x7F - 0x3A]byte
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)
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func init() {
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i := 0
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for ch := byte(0x21); ch < 0x30; ch++ {
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secKeyRandomChars[i] = ch
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i++
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}
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for ch := byte(0x3a); ch < 0x7F; ch++ {
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secKeyRandomChars[i] = ch
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i++
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}
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}
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type handshaker func(resourceName, host, origin, location, protocol string, br *bufio.Reader, bw *bufio.Writer) os.Error
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// newClient creates a new Web Socket client connection.
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func newClient(resourceName, host, origin, location, protocol string, rwc io.ReadWriteCloser) (ws *Conn, err os.Error) {
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func newClient(resourceName, host, origin, location, protocol string, rwc io.ReadWriteCloser, handshake handshaker) (ws *Conn, err os.Error) {
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br := bufio.NewReader(rwc)
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bw := bufio.NewWriter(rwc)
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err = handshake(resourceName, host, origin, location, protocol, br, bw)
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@ -76,10 +99,212 @@ func Dial(url, protocol, origin string) (ws *Conn, err os.Error) {
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if err != nil {
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return
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}
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return newClient(parsedUrl.Path, parsedUrl.Host, origin, url, protocol, client)
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return newClient(parsedUrl.RawPath, parsedUrl.Host, origin, url, protocol, client, handshake)
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}
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/*
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Generates handshake key as described in 4.1 Opening handshake
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step 16 to 22.
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cf. http://www.whatwg.org/specs/web-socket-protocol/
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*/
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func generateKeyNumber() (key string, number uint32) {
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// 16. Let /spaces_n/ be a random integer from 1 to 12 inclusive.
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spaces := rand.Intn(12) + 1
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// 17. Let /max_n/ be the largest integer not greater than
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// 4,294,967,295 divided by /spaces_n/
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max := int(4294967295 / uint32(spaces))
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// 18. Let /number_n/ be a random integer from 0 to /max_n/ inclusive.
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number = uint32(rand.Intn(max + 1))
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// 19. Let /product_n/ be the result of multiplying /number_n/ and
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// /spaces_n/ together.
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product := number * uint32(spaces)
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// 20. Let /key_n/ be a string consisting of /product_n/, expressed
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// in base ten using the numerals in the range U+0030 DIGIT ZERO (0)
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// to U+0039 DIGIT NINE (9).
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key = fmt.Sprintf("%d", product)
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// 21. Insert /spaces_n/ U+0020 SPACE characters into /key_n/ at random
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// posisions.
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for i := 0; i < spaces; i++ {
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pos := rand.Intn(len(key)-1) + 1
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key = key[0:pos] + " " + key[pos:]
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}
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// 22. Insert between one and twelve random characters from the ranges
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// U+0021 to U+002F and U+003A to U+007E into /key_n/ at random
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// positions.
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n := rand.Intn(12) + 1
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for i := 0; i < n; i++ {
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pos := rand.Intn(len(key)) + 1
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ch := secKeyRandomChars[rand.Intn(len(secKeyRandomChars))]
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key = key[0:pos] + string(ch) + key[pos:]
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}
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return
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}
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/*
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Generates handshake key_3 as described in 4.1 Opening handshake
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step 26.
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cf. http://www.whatwg.org/specs/web-socket-protocol/
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*/
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func generateKey3() (key []byte) {
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// 26. Let /key3/ be a string consisting of eight random bytes (or
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// equivalently, a random 64 bit integer encoded in big-endian order).
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key = make([]byte, 8)
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for i := 0; i < 8; i++ {
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key[i] = byte(rand.Intn(256))
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}
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return
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}
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/*
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Gets expected from challenge as described in 4.1 Opening handshake
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Step 42 to 43.
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cf. http://www.whatwg.org/specs/web-socket-protocol/
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*/
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func getExpectedForChallenge(number1, number2 uint32, key3 []byte) (expected []byte, err os.Error) {
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// 41. Let /challenge/ be the concatenation of /number_1/, expressed
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// a big-endian 32 bit integer, /number_2/, expressed in a big-
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// endian 32 bit integer, and the eight bytes of /key_3/ in the
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// order they were sent to the wire.
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challenge := make([]byte, 16)
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challengeBuf := bytes.NewBuffer(challenge)
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binary.Write(challengeBuf, binary.BigEndian, number1)
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binary.Write(challengeBuf, binary.BigEndian, number2)
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copy(challenge[8:], key3)
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// 42. Let /expected/ be the MD5 fingerprint of /challenge/ as a big-
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// endian 128 bit string.
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h := md5.New()
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if _, err = h.Write(challenge); err != nil {
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return
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}
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expected = h.Sum()
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return
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}
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/*
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Web Socket protocol handshake based on
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http://www.whatwg.org/specs/web-socket-protocol/
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(draft of http://tools.ietf.org/html/draft-hixie-thewebsocketprotocol)
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*/
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func handshake(resourceName, host, origin, location, protocol string, br *bufio.Reader, bw *bufio.Writer) (err os.Error) {
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// 4.1. Opening handshake.
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// Step 5. send a request line.
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bw.WriteString("GET " + resourceName + " HTTP/1.1\r\n")
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// Step 6-14. push request headers in fields.
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var fields vector.StringVector
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fields.Push("Upgrade: WebSocket\r\n")
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fields.Push("Connection: Upgrade\r\n")
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fields.Push("Host: " + host + "\r\n")
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fields.Push("Origin: " + origin + "\r\n")
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if protocol != "" {
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fields.Push("Sec-WebSocket-Protocol: " + protocol + "\r\n")
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}
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// TODO(ukai): Step 15. send cookie if any.
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// Step 16-23. generate keys and push Sec-WebSocket-Key<n> in fields.
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key1, number1 := generateKeyNumber()
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key2, number2 := generateKeyNumber()
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fields.Push("Sec-WebSocket-Key1: " + key1 + "\r\n")
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fields.Push("Sec-WebSocket-Key2: " + key2 + "\r\n")
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// Step 24. shuffle fields and send them out.
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for i := 1; i < len(fields); i++ {
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j := rand.Intn(i)
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fields[i], fields[j] = fields[j], fields[i]
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}
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for i := 0; i < len(fields); i++ {
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bw.WriteString(fields[i])
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}
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// Step 25. send CRLF.
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bw.WriteString("\r\n")
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// Step 26. genearte 8 bytes random key.
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key3 := generateKey3()
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// Step 27. send it out.
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bw.Write(key3)
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if err = bw.Flush(); err != nil {
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return
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}
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// Step 28-29, 32-40. read response from server.
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resp, err := http.ReadResponse(br, "GET")
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if err != nil {
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return err
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}
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// Step 30. check response code is 101.
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if resp.StatusCode != 101 {
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return ErrBadStatus
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}
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// Step 41. check websocket headers.
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upgrade, found := resp.Header["Upgrade"]
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if !found {
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return ErrNoUpgrade
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}
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if upgrade != "WebSocket" {
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return ErrBadUpgrade
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}
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connection, found := resp.Header["Connection"]
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if !found || strings.ToLower(connection) != "upgrade" {
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return ErrBadUpgrade
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}
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s, found := resp.Header["Sec-Websocket-Origin"]
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if !found {
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return ErrNoWebSocketOrigin
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}
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if s != origin {
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return ErrBadWebSocketOrigin
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}
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s, found = resp.Header["Sec-Websocket-Location"]
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if !found {
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return ErrNoWebSocketLocation
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}
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if s != location {
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return ErrBadWebSocketLocation
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}
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if protocol != "" {
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s, found = resp.Header["Sec-Websocket-Protocol"]
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if !found {
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return ErrNoWebSocketProtocol
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}
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if s != protocol {
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return ErrBadWebSocketProtocol
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}
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}
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// Step 42-43. get expected data from challange data.
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expected, err := getExpectedForChallenge(number1, number2, key3)
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if err != nil {
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return err
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}
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// Step 44. read 16 bytes from server.
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reply := make([]byte, 16)
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if _, err = io.ReadFull(br, reply); err != nil {
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return err
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}
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// Step 45. check the reply equals to expected data.
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if !bytes.Equal(expected, reply) {
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return ErrChallengeResponse
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}
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// WebSocket connection is established.
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return
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}
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/*
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Handhake described in (soon obsolete)
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draft-hixie-thewebsocket-protocol-75.
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*/
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func draft75handshake(resourceName, host, origin, location, protocol string, br *bufio.Reader, bw *bufio.Writer) (err os.Error) {
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bw.WriteString("GET " + resourceName + " HTTP/1.1\r\n")
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bw.WriteString("Upgrade: WebSocket\r\n")
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bw.WriteString("Connection: Upgrade\r\n")
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