// NewConnection creates a SSMP connection out of a streaming netwrok connection.
//
// This method blocks until either a first message is received or a 10s timeout
// elapses.
//
// Each accepted connection spawns a goroutine continuously reading from the
// underlying network connection and triggering the Dispatcher. The caller must
// keep track of the returned Connection and call the Close method to stop the
// read goroutine and close the udnerlying netwrok connection.
//
// errInvalidLogin is returned if the first message is not a well-formed LOGIN
// request.
// errUnauthorized is returned if the authenticator doesn't accept the provided
// credentials.
func NewConnection(c net.Conn, a Authenticator, d *Dispatcher) (*Connection, error) {
r := ssmp.NewDecoder(c)
c.SetReadDeadline(time.Now().Add(10 * time.Second))
verb, err := r.DecodeVerb()
if err != nil || !ssmp.Equal(verb, ssmp.LOGIN) {
return nil, ErrInvalidLogin
}
user, err := r.DecodeId()
if err != nil {
return nil, ErrInvalidLogin
}
scheme, err := r.DecodeId()
if err != nil {
return nil, ErrInvalidLogin
}
var cred []byte
if r.AtEnd() {
cred = []byte{}
} else if cred, err = r.DecodePayload(); err != nil {
return nil, ErrInvalidLogin
}
if !a.Auth(c, user, scheme, cred) {
return nil, ErrUnauthorized
}
r.Reset()
cc := &Connection{
c: c,
r: r,
User: string(user),
}
go cc.readLoop(d)
cc.Write(respOk)
return cc, nil
}
func (p *multiplexer) connectToDest(frm *frame, key string, tun *Conn) {
defer func() {
ex.CatchException(recover())
}()
var (
dstConn net.Conn
err error
target = string(frm.data)
)
dstConn, err = net.DialTimeout("tcp", target, GENERAL_SO_TIMEOUT)
frm.length = 0
if err != nil {
p.router.removePreRegistered(key)
log.Errorf("Cannot connect to [%s] for %s error: %s\n", target, key, err)
frm.action = FRAME_ACTION_OPEN_N
tunWrite2(tun, frm)
} else {
if log.V(1) {
log.Infoln("OPEN", target, "for", key)
}
dstConn.SetReadDeadline(ZERO_TIME)
edge := p.router.register(key, target, tun, dstConn, false) // write edge
frm.action = FRAME_ACTION_OPEN_Y
if tunWrite2(tun, frm) == nil {
p.relay(edge, tun, frm.sid) // read edge
} else { // send open_y failed
SafeClose(tun)
}
}
}
func (cons *Socket) processConnection(conn net.Conn) {
cons.AddWorker()
defer cons.WorkerDone()
defer conn.Close()
buffer := shared.NewBufferedReader(socketBufferGrowSize, cons.flags, cons.offset, cons.delimiter)
for cons.IsActive() && !cons.IsFuseBurned() {
conn.SetReadDeadline(time.Now().Add(cons.readTimeout))
err := buffer.ReadAll(conn, cons.Enqueue)
if err == nil {
if err = cons.sendAck(conn, true); err == nil {
continue // ### continue, all is well ###
}
}
// Silently exit on disconnect/close
if !cons.IsActive() || shared.IsDisconnectedError(err) {
return // ### return, connection closed ###
}
// Ignore timeout related errors
if netErr, isNetErr := err.(net.Error); isNetErr && netErr.Timeout() {
continue // ### return, ignore timeouts ###
}
Log.Error.Print("Socket transfer failed: ", err)
cons.sendAck(conn, false)
// Parser errors do not drop the connection
if err != shared.BufferDataInvalid {
return // ### return, close connections ###
}
}
}
func handleClient(conn net.Conn) {
conn.SetReadDeadline(time.Now().Add(2 * time.Minute))
defer conn.Close()
b := bufio.NewReader(conn)
for {
status, err := b.ReadString('\n')
if err != nil {
if err == io.EOF {
fmt.Println("Client Disconnected.")
} else {
fmt.Println(err)
}
break
}
// Clean up the input
status = strings.Replace(status, "\r", "", -1)
status = strings.Replace(status, "\n", "", -1)
switch status {
case "register":
fmt.Println("Registered")
conn.Write([]byte("Registered Client\n"))
break
default:
break
}
}
}
func connectToStdio(stdin <-chan string, conn net.Conn) {
go func() {
}()
buf := make([]byte, 1024)
for {
conn.SetReadDeadline(time.Now().Add(time.Millisecond))
n, err := conn.Read(buf[0:])
if err != nil {
nerr, ok := err.(net.Error)
if !ok || !nerr.Timeout() {
log.Println(err)
return
}
}
os.Stdout.Write(buf[:n])
select {
case msg := <-stdin:
_, err := conn.Write([]byte(msg))
if err != nil {
return
}
default:
}
}
}
func ReadMessage(conn net.Conn, timeout time.Duration) (*Message, error) {
conn.SetReadDeadline(time.Now().Add(DefaultHeartbeatTimeout))
var lengthBuf [2]byte
_, err := conn.Read(lengthBuf[:])
if err != nil {
return nil, err
}
length := int(binary.BigEndian.Uint16(lengthBuf[:]))
if length > DefaultMessageLengthCap {
return nil, errors.New("message is too long")
}
buf := bytes.NewBuffer(make([]byte, 0, length))
_, err = io.CopyN(buf, conn, int64(length))
if err != nil {
return nil, err
}
var handle = &codec.MsgpackHandle{}
var decoder = codec.NewDecoder(buf, handle)
var result = &Message{}
err = decoder.Decode(result)
if err != nil {
return nil, err
}
return result, nil
}
func handleClient(conn net.Conn) {
conn.SetReadDeadline(time.Now().Add(2 * time.Minute))
request := make([]byte, 128)
defer conn.Close()
for {
read_len, err := conn.Read(request)
fmt.Println(read_len)
if err != nil {
fmt.Println(err)
break
}
if read_len == 0 {
break
} else if string(request) == "timestamp" {
daytime := strconv.FormatInt(time.Now().Unix(), 10)
conn.Write([]byte(daytime))
} else {
daytime := time.Now().String()
conn.Write([]byte(daytime))
}
request = make([]byte, 128)
}
}
func handleConn(conn net.Conn) {
defer conn.Close()
for {
conn.SetReadDeadline(time.Now().Add(10 * time.Second))
strReq, err := read(conn)
if err != nil {
if err == io.EOF {
fmt.Println("The connection is closed by another side. (Server)")
} else {
fmt.Printf("Read Error: %s (Server)\n", err)
}
break
}
fmt.Printf("Received request: %s (Server)\n", strReq)
i32Req, err := strconv.Atoi(strReq)
if err != nil {
n, err := write(conn, err.Error())
if err != nil {
fmt.Printf("Write Eoor (writen %d bytes:) %s (Server)\n", err)
}
fmt.Printf("Sent response (written %d bytes %s (server)\n", n, err)
continue
}
f64Resp := math.Cbrt(float64(i32Req))
respMsg := fmt.Sprintf("The cube root of %d is %f.", i32Req, f64Resp)
n, err := write(conn, respMsg)
if err != nil {
fmt.Printf("Write Error: %s (Server)\n", err)
}
fmt.Printf("Sent response (writtn %d bytes:) %s (Server)\n", n, respMsg)
}
}
// testRacyRead tests that it is safe to mutate the input Read buffer
// immediately after cancelation has occurred.
func testRacyRead(t *testing.T, c1, c2 net.Conn) {
go chunkedCopy(c2, rand.New(rand.NewSource(0)))
var wg sync.WaitGroup
defer wg.Wait()
c1.SetReadDeadline(time.Now().Add(time.Millisecond))
for i := 0; i < 10; i++ {
wg.Add(1)
go func() {
defer wg.Done()
b1 := make([]byte, 1024)
b2 := make([]byte, 1024)
for j := 0; j < 100; j++ {
_, err := c1.Read(b1)
copy(b1, b2) // Mutate b1 to trigger potential race
if err != nil {
checkForTimeoutError(t, err)
c1.SetReadDeadline(time.Now().Add(time.Millisecond))
}
}
}()
}
}
// ----------------------------------------------------------------------
//
// RECEIVE LOGIC
//
// ----------------------------------------------------------------------
func conn_read(conn net.Conn, timeout time.Duration, buffer []byte) (int, error) {
if timeout != time.Duration(0) {
conn.SetReadDeadline(time.Now().Add(timeout))
}
position := 0
length := len(buffer)
for position < length {
bytesRead, err := conn.Read(buffer[position:])
if err != nil {
if err == io.EOF {
log.Println("conn_read", "CLOSED")
return 0, CHANNEL_CLOSED
} else if neterr, ok := err.(net.Error); ok && neterr.Timeout() {
log.Println("conn_read", "TIMEOUT")
return 0, CHANNEL_TIMEOUT
} else {
// we should do better than this
log.Println("conn_read", err)
return 0, CHANNEL_CLOSED
}
} else {
position += bytesRead
}
}
return position, nil
}
// monitorConnection is called for bidi connections and watches for the client
// to disappear. this func blocks until the connection closes or generates a
// a non-timeout error (possibly protocol related).
func (w *Writer) monitorConnection(conn net.Conn) {
defer close(w.finish)
var err error
for {
conn.SetReadDeadline(time.Now().Add(1 * time.Second))
// test the connection by attempting to read a FINISH control frame.
// we should only see this if we've initiated a close by sending a
// STOP, but it doesn't hurt to start watching for this before then
// because we're really not expecting the client to send anything
// else at this point. we also don't have to write anything special
// back to the client if we receive it because the client closes their
// end of the connection upon sending.
_, err = w.readControl(ControlTypeFinish)
if err == io.EOF {
// connection closed
} else if neterr, ok := err.(net.Error); ok && neterr.Timeout() {
// timeout
time.Sleep(5 * time.Second) // TODO(jdef) extract constant
continue
}
break
}
w.setError(err)
}
func NewConn(client *Client, network, addr string, connectTimeout, readTimeout, writeTimeout time.Duration) (*Conn, error) {
client.CountNewConn++
var conn net.Conn
var err error
if connectTimeout > 0 {
conn, err = net.DialTimeout(network, addr, connectTimeout)
} else {
conn, err = net.Dial(network, addr)
}
if err != nil {
return nil, err
}
if readTimeout > 0 {
conn.SetReadDeadline(time.Now().Add(readTimeout))
}
if writeTimeout > 0 {
conn.SetWriteDeadline(time.Now().Add(writeTimeout))
}
this := &Conn{
Conn: conn,
Client: client,
ReadTimeout: readTimeout,
WriteTimeout: writeTimeout,
}
return this, nil
}
func copyBytes(dst, src net.Conn, wg *sync.WaitGroup, writeDeadline, readDeadline time.Duration) {
defer wg.Done()
n, err := io.Copy(dst, src)
if err != nil {
log.Errorf("proxy i/o error: %v", err)
}
if cr, ok := src.(*net.TCPConn); ok {
cr.CloseRead()
} else {
// For TLS connections.
wto := time.Now().Add(writeDeadline)
src.SetWriteDeadline(wto)
}
if cw, ok := dst.(*net.TCPConn); ok {
cw.CloseWrite()
} else {
// For TLS connections.
rto := time.Now().Add(readDeadline)
dst.SetReadDeadline(rto)
}
log.Debugf("proxy copied %d bytes %s -> %s", n, src.RemoteAddr(), dst.RemoteAddr())
}
func handleConnection(conn net.Conn) {
defer conn.Close()
conn.SetReadDeadline(time.Now().Add(time.Second * 3))
r := bufio.NewReader(conn)
size, err := r.ReadString(';')
if err != nil {
log.Println(err)
fmt.Fprintf(conn, "Failed to read content length: %v\n", err)
return
}
size = size[:len(size)-1]
i, err := strconv.Atoi(size)
if err != nil {
log.Println(err)
fmt.Fprintf(conn, "Failed to get content length from %s: %v\n", size, err)
return
}
b := make([]byte, i)
r.Read(b)
intent := content.Intent{}
if err := json.Unmarshal(b, &intent); err != nil {
log.Println(err)
fmt.Fprintf(conn, "Failed to decode request: %v", err)
}
content.Handle(conn, intent)
}
func (s *session) proxy(c1, c2 net.Conn) error {
if debug {
log.Println("Proxy", c1.RemoteAddr(), "->", c2.RemoteAddr())
}
atomic.AddInt64(&numProxies, 1)
defer atomic.AddInt64(&numProxies, -1)
buf := make([]byte, 65536)
for {
c1.SetReadDeadline(time.Now().Add(networkTimeout))
n, err := c1.Read(buf)
if err != nil {
return err
}
atomic.AddInt64(&bytesProxied, int64(n))
if debug {
log.Printf("%d bytes from %s to %s", n, c1.RemoteAddr(), c2.RemoteAddr())
}
if s.rateLimit != nil {
s.rateLimit(int64(n))
}
c2.SetWriteDeadline(time.Now().Add(networkTimeout))
_, err = c2.Write(buf[:n])
if err != nil {
return err
}
}
}
func (mux *Mux) handleConn(conn net.Conn) error {
// Wrap in a buffered connection in order to peek at the first byte.
bufConn := newBufConn(conn)
// Set a read deadline so connections with no data timeout.
if err := conn.SetReadDeadline(time.Now().Add(mux.Timeout)); err != nil {
return fmt.Errorf("set read deadline: %s", err)
}
// Peek at first byte from connection to determine handler.
typ, err := bufConn.r.ReadByte()
if err != nil {
return fmt.Errorf("read header byte: %s", err)
} else if err = bufConn.r.UnreadByte(); err != nil {
return fmt.Errorf("unread header byte: %s", err)
}
// Reset read deadline and let the listener handle that.
if err := conn.SetReadDeadline(time.Time{}); err != nil {
return fmt.Errorf("reset set read deadline: %s", err)
}
// Lookup handler.
h := mux.handlers[typ]
if h == nil {
return fmt.Errorf("unregistered header byte: 0x%02x", typ)
}
// Hand off connection to handler.
h.c <- bufConn
return nil
}
func handleConn(conn net.Conn) {
defer func() {
conn.Close()
wg.Done()
}()
for {
conn.SetReadDeadline(time.Now().Add(10 * time.Second))
strReq, err := read(conn)
if err != nil {
if err == io.EOF {
printLog("The connection is closed by another side. (Server)\n")
} else {
printLog("Read Error: %s (Server)\n", err)
}
break
}
printLog("Received request: %s (Server)\n", strReq)
i32Req, err := convertToInt32(strReq)
if err != nil {
n, err := write(conn, err.Error())
if err != nil {
printLog("Write Error (written %d bytes): %s (Server)\n", err)
}
printLog("Sent response (written %d bytes): %s (Server)\n", n, err)
continue
}
f64Resp := cbrt(i32Req)
respMsg := fmt.Sprintf("The cube root of %d is %f.", i32Req, f64Resp)
n, err := write(conn, respMsg)
if err != nil {
printLog("Write Error: %s (Server)\n", err)
}
printLog("Sent response (written %d bytes): %s (Server)\n", n, respMsg)
}
}
func DefaultDial(proto, realm string) (io.ReadWriteCloser, error) {
if proto != "tcp" && proto != "udp" {
return nil, ErrInvalidProto(proto)
}
_, addrs, err := net.LookupSRV("kerberos", proto, realm)
if err != nil {
_, addrs, err = net.LookupSRV("kerberos-master", proto, realm)
if err != nil {
return nil, err
}
}
var sock net.Conn
for _, a := range addrs {
addr := net.JoinHostPort(a.Target, strconv.Itoa(int(a.Port)))
sock, err = net.Dial(proto, addr)
if err == nil {
break
}
}
if err != nil {
return nil, err
}
if proto == "udp" {
// For datagram connections, we retry up to three times, then give up
sock.SetReadDeadline(time.Now().Add(udpReadTimeout))
}
return sock, nil
}
func (rcv *TCP) handleConnection(conn net.Conn) {
atomic.AddInt32(&rcv.active, 1)
defer atomic.AddInt32(&rcv.active, -1)
defer conn.Close()
reader := bufio.NewReader(conn)
for {
conn.SetReadDeadline(time.Now().Add(2 * time.Minute))
line, err := reader.ReadBytes('\n')
if err != nil {
if err == io.EOF {
if len(line) > 0 {
logrus.Warningf("[tcp] Unfinished line: %#v", line)
}
} else {
atomic.AddUint32(&rcv.errors, 1)
logrus.Error(err)
}
break
}
if len(line) > 0 { // skip empty lines
if msg, err := points.ParseText(string(line)); err != nil {
atomic.AddUint32(&rcv.errors, 1)
logrus.Info(err)
} else {
atomic.AddUint32(&rcv.metricsReceived, 1)
rcv.out <- msg
}
}
}
}
// poll sends a packet and wait for a response. Both operations can timeout, they're retried up to retries times.
func poll(conn net.Conn, toSend []byte, respondBuffer []byte, retries int, timeout time.Duration) (int, error) {
var err error
for i := 0; i < retries+1; i++ {
deadline := time.Now().Add(timeout)
if err = conn.SetWriteDeadline(deadline); err != nil {
log.Printf("Couldn't set write deadline. Retrying. Retry %d/%d\n", i, retries)
continue
}
if _, err = conn.Write(toSend); err != nil {
log.Printf("Couldn't write. Retrying. Retry %d/%d\n", i, retries)
continue
}
deadline = time.Now().Add(timeout)
if err = conn.SetReadDeadline(deadline); err != nil {
log.Printf("Couldn't set read deadline. Retrying. Retry %d/%d\n", i, retries)
continue
}
numRead := 0
if numRead, err = conn.Read(respondBuffer); err != nil {
log.Printf("Couldn't read. Retrying. Retry %d/%d\n", i, retries)
continue
}
return numRead, nil
}
return 0, err
}
func slurp(conn net.Conn, maxbytes int, timeout float64) ([]byte, error) {
buf := []byte{}
readLimit := 32 * 1024
if maxbytes > 0 {
readLimit = maxbytes
}
readBytes := 0
if timeout > 0 {
conn.SetReadDeadline(time.Now().Add(time.Duration(timeout) * time.Second))
}
for {
tmpBuf := make([]byte, readLimit)
i, err := conn.Read(tmpBuf)
if i > 0 {
buf = append(buf, tmpBuf[:i]...)
readBytes += i
if i < readLimit || (maxbytes > 0 && maxbytes <= readBytes) {
break
}
}
if err == io.EOF {
return buf, nil
}
if err != nil {
return buf, err
}
}
return buf, nil
}
func (srv *Server) readTCP(conn net.Conn, timeout time.Duration) ([]byte, error) {
conn.SetReadDeadline(time.Now().Add(timeout))
l := make([]byte, 2)
n, err := conn.Read(l)
if err != nil || n != 2 {
if err != nil {
return nil, err
}
return nil, ErrShortRead
}
length := binary.BigEndian.Uint16(l)
if length == 0 {
return nil, ErrShortRead
}
m := make([]byte, int(length))
n, err = conn.Read(m[:int(length)])
if err != nil || n == 0 {
if err != nil {
return nil, err
}
return nil, ErrShortRead
}
i := n
for i < int(length) {
j, err := conn.Read(m[i:int(length)])
if err != nil {
return nil, err
}
i += j
}
n = i
m = m[:n]
return m, nil
}
func handleConn(conn net.Conn) {
defer conn.Close()
// Read from connection
buf := make([]byte, 512)
conn.SetReadDeadline(time.Now().Add(TIMEOUT))
n, err := conn.Read(buf)
if err != nil {
return
}
// Unmarshal message
msg := Message{}
err = json.Unmarshal(buf[:n], &msg)
// Handle message
switch msg.Type {
case MSG_VOTE:
fmt.Printf("%d: Got vote message.\n", id)
go announceVote()
fallthrough
case MSG_PING:
fmt.Printf("%d: Sending 'alive' message.\n", id)
response := Message{Type: MSG_ALIVE, Sender: id}
conn.Write(response.ToJSON())
case MSG_LEADER:
if msg.Sender > id {
setLeader(msg.Sender)
} else {
fmt.Printf("%d: Leader with lower ID. Bullying!\n", id)
go announceVote()
}
}
}
func (srv *Server) sentinel(c net.Conn, connClosed chan int) {
select {
case <-srv.stopAccepting:
c.SetReadDeadline(time.Now().Add(3 * time.Second))
case <-connClosed:
}
}
func handleClient(conn net.Conn) {
// defer conn.Close()
// daytime := time.Now().String()
// conn.Write([]byte(daytime))
conn.SetReadDeadline(time.Now().Add(2 * time.Minute)) // set 2 minutes timeout
request := make([]byte, 128) // set maxium request length to 128KB to prevent flood attack
defer conn.Close() // close connection before exit
for {
read_len, err := conn.Read(request)
fmt.Println("read info: ", string(request))
if err != nil {
fmt.Println(err)
break
}
fmt.Println(string(request))
if read_len == 0 {
break // connection already closed by client
} else if string(request) == "timestamp" {
fmt.Println("daytime timestamp")
daytime := strconv.FormatInt(time.Now().Unix(), 10)
conn.Write([]byte(daytime))
} else {
daytime := time.Now().String()
conn.Write([]byte(daytime))
}
request = make([]byte, 128) // clear last read content
}
}
func (mux *Mux) handleConn(conn net.Conn) {
defer mux.wg.Done()
// Set a read deadline so connections with no data don't timeout.
if err := conn.SetReadDeadline(time.Now().Add(mux.Timeout)); err != nil {
conn.Close()
mux.Logger.Printf("tcp.Mux: cannot set read deadline: %s", err)
return
}
// Read first byte from connection to determine handler.
var typ [1]byte
if _, err := io.ReadFull(conn, typ[:]); err != nil {
conn.Close()
mux.Logger.Printf("tcp.Mux: cannot read header byte: %s", err)
return
}
// Reset read deadline and let the listener handle that.
if err := conn.SetReadDeadline(time.Time{}); err != nil {
conn.Close()
mux.Logger.Printf("tcp.Mux: cannot reset set read deadline: %s", err)
return
}
// Retrieve handler based on first byte.
handler := mux.m[typ[0]]
if handler == nil {
conn.Close()
mux.Logger.Printf("tcp.Mux: handler not registered: %d", typ[0])
return
}
// Send connection to handler. The handler is responsible for closing the connection.
handler.c <- conn
}
func handleClient(conn net.Conn) {
conn.SetReadDeadline(time.Now().Add(2 * time.Minute)) // 2分钟无接收信息超时
//func (c *TCPConn) SetReadDeadline(t time.Time) error
//func (c *TCPConn) SetWriteDeadline(t time.Time) error
defer conn.Close()
for {
request := make([]byte, 128)
//128 位读取信息
read_len, err := conn.Read(request)
if err != nil {
fmt.Println(err)
break
}
if read_len == 0 {
break // connection already closed by client
} else if string(request) == "timestamp" {
daytime := strconv.FormatInt(time.Now().Unix(), 10)
conn.Write([]byte(daytime))
} else {
daytime := time.Now().String()
conn.Write([]byte(daytime))
}
}
}
func (s *Server) handle(clientConn net.Conn, id int) {
log.Debug("[tcpez] New client(%s)", clientConn.RemoteAddr())
s.clientConns[id] = clientConn
for {
// Timeout the connection after 5 mins
clientConn.SetReadDeadline(time.Now().Add(5 * time.Minute))
header, response, err := s.readHeaderAndHandleRequest(clientConn)
if err != nil {
if closableError(err) {
// EOF the client has disconnected
break
}
log.Error(err.Error())
s.Stats.Increment("operation.failure")
return
}
err = s.sendResponse(clientConn, header, response)
if err != nil {
if closableError(err) {
// EOF the client has disconnected
break
}
log.Error(err.Error())
s.Stats.Increment("operation.failure")
return
}
s.Stats.Increment("operation.success")
}
log.Debug("Closing connection %v", clientConn)
clientConn.Close()
delete(s.clientConns, id)
}
func (t *Telnet) recv(c net.Conn) (int, error) {
buf := make([]byte, 512)
count := 0
for {
err := c.SetReadDeadline(time.Now().Add(time.Millisecond * 500))
if err != nil {
return count, fmt.Errorf("setting read deadline: %v\n", err)
}
n, err := c.Read(buf)
if err != nil {
if neterr, ok := err.(net.Error); ok && neterr.Timeout() {
return count, nil
}
return count, fmt.Errorf("read error: %v\n", err)
}
for i := 0; i < n; i++ {
if cnt := t.decodeCommand(buf[i:n]); cnt > 0 {
i += cnt
continue
}
t.debugf("%2.2x %c\n", buf[i], buf[i])
}
count += n
if time.Now().After(t.deadline) {
return count, errors.New("deadline exceeded")
}
}
}
func SockRead(con net.Conn, buf []byte) (n int, e error) {
var toread int
bw_mutex.Lock()
TickRecv()
if DownloadLimit == 0 {
toread = len(buf)
} else {
toread = int(DownloadLimit) - dl_bytes_so_far
if toread > len(buf) {
toread = len(buf)
} else if toread < 0 {
toread = 0
}
}
dl_bytes_so_far += toread
bw_mutex.Unlock()
if toread > 0 {
// Wait 1 millisecond for a data, timeout if nothing there
con.SetReadDeadline(time.Now().Add(100 * time.Millisecond))
n, e = con.Read(buf[:toread])
bw_mutex.Lock()
DlBytesTotal += uint64(n)
dl_bytes_priod += uint64(n)
bw_mutex.Unlock()
} else {
// supsend a task for awhile, to prevent stucking in a busy loop
time.Sleep(100 * time.Millisecond)
}
return
}
