Golang syscall.WSARecvFrom函数代码示例

func timeoutIO() {
	// CancelIO only cancels all pending input and output (I/O) operations that are
	// issued by the calling thread for the specified file, does not cancel I/O
	// operations that other threads issue for a file handle. So we need do all timeout
	// I/O in single OS thread.
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()
	for {
		o := <-ioChan
		var e int
		switch o.f {
		case read:
			e = syscall.WSARecv(uint32(o.fd.sysfd), o.pckt.w, 1, o.done, o.flags, &o.pckt.o, nil)
		case readfrom:
			e = syscall.WSARecvFrom(uint32(o.fd.sysfd), o.pckt.w, 1, o.done, o.flags, o.rsa, o.size, &o.pckt.o, nil)
		case write:
			e = syscall.WSASend(uint32(o.fd.sysfd), o.pckt.w, 1, o.done, uint32(0), &o.pckt.o, nil)
		case writeto:
			e = syscall.WSASendto(uint32(o.fd.sysfd), o.pckt.w, 1, o.done, 0, *o.sa, &o.pckt.o, nil)
		case cancel:
			_, e = syscall.CancelIo(uint32(o.fd.sysfd))
		}
		o.c <- e
	}
}

func (s *Ssdp) read() ([]byte, string, error) {
	bufs := syscall.WSABuf{
		Len: 2048,
		Buf: &s.socket.readBytes[0],
	}
	var n, flags uint32
	var asIp4 syscall.RawSockaddrInet4
	fromAny := (*syscall.RawSockaddrAny)(unsafe.Pointer(&asIp4))
	fromSize := int32(unsafe.Sizeof(asIp4))
	err := syscall.WSARecvFrom(s.socket.socket, &bufs, 1, &n, &flags, fromAny, &fromSize, nil, nil)
	if err != nil {
		return nil, "", err
	}
	if n > 0 {
		// need to convert the port bytes ordering
		portBytes := make([]byte, 6)
		binary.BigEndian.PutUint16(portBytes, asIp4.Port)
		port := binary.LittleEndian.Uint16(portBytes)
		// set the address
		src := fmt.Sprintf("%d.%d.%d.%d:%d", asIp4.Addr[0], asIp4.Addr[1], asIp4.Addr[2], asIp4.Addr[3], port)
		//s.logger.Infof("Message: %s", string(readBytes[0:n]))
		return s.socket.readBytes[0:n], src, nil
	}
	return nil, "", nil
}

func (fd *netFD) readFrom(buf []byte) (int, syscall.Sockaddr, error) {
	if len(buf) == 0 {
		return 0, nil, nil
	}
	if err := fd.readLock(); err != nil {
		return 0, nil, err
	}
	defer fd.readUnlock()
	o := &fd.rop
	o.InitBuf(buf)
	n, err := rsrv.ExecIO(o, "WSARecvFrom", func(o *operation) error {
		if o.rsa == nil {
			o.rsa = new(syscall.RawSockaddrAny)
		}
		o.rsan = int32(unsafe.Sizeof(*o.rsa))
		return syscall.WSARecvFrom(o.fd.sysfd, &o.buf, 1, &o.qty, &o.flags, o.rsa, &o.rsan, &o.o, nil)
	})
	err = fd.eofError(n, err)
	if _, ok := err.(syscall.Errno); ok {
		err = os.NewSyscallError("wsarecvfrom", err)
	}
	if err != nil {
		return n, nil, err
	}
	sa, _ := o.rsa.Sockaddr()
	return n, sa, nil
}

func (fd *netFD) ReadFrom(p []byte) (n int, sa syscall.Sockaddr, err os.Error) {
	if fd == nil {
		return 0, nil, os.EINVAL
	}
	if len(p) == 0 {
		return 0, nil, nil
	}
	fd.rio.Lock()
	defer fd.rio.Unlock()
	fd.incref()
	defer fd.decref()
	if fd.sysfd == -1 {
		return 0, nil, os.EINVAL
	}
	// Submit receive request.
	var pckt ioPacket
	pckt.c = fd.cr
	pckt.w = newWSABuf(p)
	var done uint32
	flags := uint32(0)
	var rsa syscall.RawSockaddrAny
	l := int32(unsafe.Sizeof(rsa))
	var e int
	if fd.rdeadline_delta > 0 {
		a := &arg{f: readfrom, fd: fd, pckt: &pckt, done: &done, flags: &flags, rsa: &rsa, size: &l, c: make(chan int)}
		ioChan <- a
		e = <-a.c
	} else {
		e = syscall.WSARecvFrom(uint32(fd.sysfd), pckt.w, 1, &done, &flags, &rsa, &l, &pckt.o, nil)
	}
	switch e {
	case 0:
		// IO completed immediately, but we need to get our completion message anyway.
	case syscall.ERROR_IO_PENDING:
		// IO started, and we have to wait for it's completion.
	default:
		return 0, nil, &OpError{"WSARecvFrom", fd.net, fd.laddr, os.Errno(e)}
	}
	// Wait for our request to complete.
	r := waitPacket(fd, &pckt, 'r')
	if r.errno != 0 {
		err = &OpError{"WSARecvFrom", fd.net, fd.laddr, os.Errno(r.errno)}
	}
	n = int(r.qty)
	sa, _ = rsa.Sockaddr()
	return
}

func (fd *netFD) ReadFrom(buf []byte) (n int, sa syscall.Sockaddr, err error) {
	if len(buf) == 0 {
		return 0, nil, nil
	}
	if err := fd.readLock(); err != nil {
		return 0, nil, err
	}
	defer fd.readUnlock()
	o := &fd.rop
	o.InitBuf(buf)
	n, err = rsrv.ExecIO(o, "WSARecvFrom", func(o *operation) error {
		if o.rsa == nil {
			o.rsa = new(syscall.RawSockaddrAny)
		}
		o.rsan = int32(unsafe.Sizeof(*o.rsa))
		return syscall.WSARecvFrom(o.fd.sysfd, &o.buf, 1, &o.qty, &o.flags, o.rsa, &o.rsan, &o.o, nil)
	})
	if err != nil {
		return 0, nil, err
	}
	sa, _ = o.rsa.Sockaddr()
	return
}

func (o *readFromOp) Submit() error {
	var d, f uint32
	return syscall.WSARecvFrom(o.fd.sysfd, &o.buf, 1, &d, &f, &o.rsa, &o.rsan, &o.o, nil)
}

func (o *readFromOp) Submit() (errno int) {
	var d, f uint32
	l := int32(unsafe.Sizeof(o.rsa))
	return syscall.WSARecvFrom(o.fd.sysfd, &o.buf, 1, &d, &f, &o.rsa, &l, &o.o, nil)
}