forked from siddontang/go
/
conn.go
321 lines (253 loc) · 5.85 KB
/
conn.go
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package websocket
import (
"bufio"
"encoding/binary"
"errors"
"io"
"math/rand"
"net"
"time"
)
//refer RFC6455
const (
TextMessage byte = 1
BinaryMessage byte = 2
CloseMessage byte = 8
PingMessage byte = 9
PongMessage byte = 10
)
var (
ErrControlTooLong = errors.New("control message too long")
ErrRSVNotSupport = errors.New("reserved bit not support")
ErrPayloadError = errors.New("payload length error")
ErrControlFragmented = errors.New("control message can not be fragmented")
ErrNotTCPConn = errors.New("not a tcp connection")
ErrWriteError = errors.New("write error")
)
type Conn struct {
conn net.Conn
br *bufio.Reader
isServer bool
}
func NewConn(conn net.Conn, isServer bool) *Conn {
c := new(Conn)
c.conn = conn
c.br = bufio.NewReader(conn)
c.isServer = isServer
return c
}
func (c *Conn) ReadMessage() (messageType byte, message []byte, err error) {
return c.Read()
}
func (c *Conn) Read() (messageType byte, message []byte, err error) {
buf := make([]byte, 8, 8)
message = []byte{}
messageType = 0
for {
opcode, data, err := c.readFrame(buf)
if err != nil {
return messageType, message, err
}
message = append(message, data...)
if opcode&0x80 != 0 {
//final
if opcode&0x0F > 0 {
//not continue frame
messageType = opcode & 0x0F
}
return messageType, message, nil
} else {
if opcode&0x0F > 0 {
//first continue frame
messageType = opcode & 0x0F
}
}
}
return
}
func (c *Conn) Write(message []byte, binary bool) error {
if binary {
return c.sendFrame(BinaryMessage, message)
} else {
return c.sendFrame(TextMessage, message)
}
}
func (c *Conn) WriteMessage(messageType byte, message []byte) error {
return c.sendFrame(messageType, message)
}
//write utf-8 text message
func (c *Conn) WriteString(message []byte) error {
return c.Write(message, false)
}
//write binary message
func (c *Conn) WriteBinary(message []byte) error {
return c.Write(message, true)
}
func (c *Conn) Ping(message []byte) error {
return c.sendFrame(PingMessage, message)
}
func (c *Conn) Pong(message []byte) error {
return c.sendFrame(PongMessage, message)
}
//close socket, not send websocket close message
func (c *Conn) Close() error {
return c.conn.Close()
}
func (c *Conn) LocalAddr() net.Addr {
return c.conn.LocalAddr()
}
func (c *Conn) RemoteAddr() net.Addr {
return c.conn.RemoteAddr()
}
func (c *Conn) SetReadDeadline(t time.Time) error {
return c.conn.SetReadDeadline(t)
}
func (c *Conn) SetWriteDeadline(t time.Time) error {
return c.conn.SetWriteDeadline(t)
}
func (c *Conn) SetReadBuffer(bytes int) error {
if tcpConn, ok := c.conn.(*net.TCPConn); ok {
return tcpConn.SetReadBuffer(bytes)
} else {
return ErrNotTCPConn
}
}
func (c *Conn) SetWriteBuffer(bytes int) error {
if tcpConn, ok := c.conn.(*net.TCPConn); ok {
return tcpConn.SetWriteBuffer(bytes)
} else {
return ErrNotTCPConn
}
}
func (c *Conn) readPayloadLen(length byte, buf []byte) (payloadLen uint64, err error) {
if length < 126 {
payloadLen = uint64(length)
} else if length == 126 {
err = c.read(buf[:2])
if err != nil {
return
}
payloadLen = uint64(binary.BigEndian.Uint16(buf[:2]))
} else if length == 127 {
err = c.read(buf[:8])
if err != nil {
return
}
payloadLen = uint64(binary.BigEndian.Uint16(buf[:8]))
}
return
}
func (c *Conn) readFrame(buf []byte) (opcode byte, messsage []byte, err error) {
//minimum head may 2 byte
err = c.read(buf[:2])
if err != nil {
return
}
opcode = buf[0]
if opcode&0x70 > 0 {
err = ErrRSVNotSupport
return
}
//isMasking := (0x80 & buf[1]) > 0
isMasking := (0x80 & buf[1]) > 0
var payloadLen uint64
payloadLen, err = c.readPayloadLen(buf[1]&0x7F, buf)
if err != nil {
return
}
if opcode&0x08 > 0 && payloadLen > 125 {
err = ErrControlTooLong
return
}
var masking []byte
if isMasking {
err = c.read(buf[:4])
if err != nil {
return
}
masking = buf[:4]
}
messsage = make([]byte, payloadLen)
err = c.read(messsage)
if err != nil {
return
}
if isMasking {
//maskingKey := c.newMaskingKey()
c.maskingData(messsage, masking)
}
return
}
func (c *Conn) sendFrame(opcode byte, message []byte) error {
//max frame header may 14 length
buf := make([]byte, 0, len(message)+14)
//here we don not support continue frame, all are final
opcode |= 0x80
if opcode&0x08 > 0 && len(message) >= 126 {
return ErrControlTooLong
}
buf = append(buf, opcode)
//no mask, because chrome may not support
var mask byte = 0x00
if !c.isServer {
//for client, we will mask data
mask = 0x80
}
payloadLen := len(message)
if payloadLen < 126 {
buf = append(buf, mask|byte(payloadLen))
} else if payloadLen <= 0xFFFF {
buf = append(buf, mask|byte(126), 0, 0)
binary.BigEndian.PutUint16(buf[len(buf)-2:], uint16(payloadLen))
} else {
buf = append(buf, mask|byte(127), 0, 0, 0, 0, 0, 0, 0, 0)
binary.BigEndian.PutUint64(buf[len(buf)-8:], uint64(payloadLen))
}
if !c.isServer {
maskingKey := c.newMaskingKey()
buf = append(buf, maskingKey...)
pos := len(buf)
buf = append(buf, message...)
c.maskingData(buf[pos:], maskingKey)
} else {
buf = append(buf, message...)
}
tmpBuf := buf
for i := 0; i < 3; i++ {
n, err := c.conn.Write(tmpBuf)
if err != nil {
return err
}
if n == len(tmpBuf) {
return nil
} else {
tmpBuf = tmpBuf[n:]
}
}
return ErrWriteError
}
func (c *Conn) read(buf []byte) error {
var err error
for len(buf) > 0 && err == nil {
var nn int
nn, err = c.br.Read(buf)
buf = buf[nn:]
}
if err == io.EOF {
if len(buf) == 0 {
err = nil
} else {
err = io.ErrUnexpectedEOF
}
}
return err
}
func (c *Conn) maskingData(data []byte, maskingKey []byte) {
for i := range data {
data[i] ^= maskingKey[i%4]
}
}
func (c *Conn) newMaskingKey() []byte {
n := rand.Uint32()
return []byte{byte(n), byte(n >> 8), byte(n >> 16), byte(n >> 32)}
}