//------------------------------------------------------------------------------
// Copyright (C) 2011, Robert Johansson, Raditex AB
// All rights reserved.
//
// rSCADA
// http://www.rSCADA.se
// info@rscada.se
//
//------------------------------------------------------------------------------
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <stdio.h>
#include <strings.h>
#include <termios.h>
#include <errno.h>
#include <string.h>
#include "mbus-serial.h"
#include "mbus-protocol-aux.h"
#include "mbus-protocol.h"
#define PACKET_BUFF_SIZE 2048
//------------------------------------------------------------------------------
/// Set up a serial connection handle.
//------------------------------------------------------------------------------
int
mbus_serial_connect(mbus_handle *handle)
{
mbus_serial_data *serial_data;
const char *device;
struct termios *term;
if (handle == NULL)
return -1;
serial_data = (mbus_serial_data *) handle->auxdata;
if (serial_data == NULL || serial_data->device == NULL)
return -1;
device = serial_data->device;
term = &(serial_data->t);
//
// create the SERIAL connection
//
// Use blocking read and handle it by serial port VMIN/VTIME setting
if ((handle->fd = open(device, O_RDWR | O_NOCTTY)) < 0)
{
fprintf(stderr, "%s: failed to open tty.", __PRETTY_FUNCTION__);
return -1;
}
memset(term, 0, sizeof(*term));
term->c_cflag |= (CS8|CREAD|CLOCAL);
term->c_cflag |= PARENB;
// No received data still OK
term->c_cc[VMIN] = 0;
// Wait at most 0.2 sec.Note that it starts after first received byte!!
// I.e. if CMIN>0 and there are no data we would still wait forever...
//
// The specification mentions link layer response timeout this way:
// The time structure of various link layer communication types is described in EN60870-5-1. The answer time
// between the end of a master send telegram and the beginning of the response telegram of the slave shall be
// between 11 bit times and (330 bit times + 50ms).
//
// For 2400Bd this means (330 + 11) / 2400 + 0.05 = 188.75 ms (added 11 bit periods to receive first byte).
// I.e. timeout of 0.2s seems appropriate for 2400Bd.
term->c_cc[VTIME] = 2; // Timeout in 1/10 sec
cfsetispeed(term, B2400);
cfsetospeed(term, B2400);
#ifdef MBUS_SERIAL_DEBUG
printf("%s: t.c_cflag = %x\n", __PRETTY_FUNCTION__, term->c_cflag);
printf("%s: t.c_oflag = %x\n", __PRETTY_FUNCTION__, term->c_oflag);
printf("%s: t.c_iflag = %x\n", __PRETTY_FUNCTION__, term->c_iflag);
printf("%s: t.c_lflag = %x\n", __PRETTY_FUNCTION__, term->c_lflag);
#endif
tcsetattr(handle->fd, TCSANOW, term);
return 0;
}
//------------------------------------------------------------------------------
// Set baud rate for serial connection
//------------------------------------------------------------------------------
int
mbus_serial_set_baudrate(mbus_handle *handle, int baudrate)
{
speed_t speed;
if (handle == NULL)
return -1;
mbus_serial_data *serial_data = (mbus_serial_data *) handle->auxdata;
switch (baudrate)
{
case 300:
speed = B300;
serial_data->t.c_cc[VTIME] = 12; // Timeout in 1/10 sec
break;
case 600:
speed = B600;
serial_data->t.c_cc[VTIME] = 6; // Timeout in 1/10 sec
break;
case 1200:
speed = B1200;
serial_data->t.c_cc[VTIME] = 4; // Timeout in 1/10 sec
break;
case 2400:
speed = B2400;
serial_data->t.c_cc[VTIME] = 2; // Timeout in 1/10 sec
break;
case 4800:
speed = B4800;
serial_data->t.c_cc[VTIME] = 2; // Timeout in 1/10 sec
break;
case 9600:
speed = B9600;
serial_data->t.c_cc[VTIME] = 1; // Timeout in 1/10 sec
break;
case 19200:
speed = B19200;
serial_data->t.c_cc[VTIME] = 1; // Timeout in 1/10 sec
break;
case 38400:
speed = B38400;
serial_data->t.c_cc[VTIME] = 1; // Timeout in 1/10 sec
break;
default:
return -1; // unsupported baudrate
}
// Set input baud rate
if (cfsetispeed(&(serial_data->t), speed) != 0)
{
return -1;
}
// Set output baud rate
if (cfsetospeed(&(serial_data->t), speed) != 0)
{
return -1;
}
// Change baud rate immediately
if (tcsetattr(handle->fd, TCSANOW, &(serial_data->t)) != 0)
{
return -1;
}
return 0;
}
//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
int
mbus_serial_disconnect(mbus_handle *handle)
{
if (handle == NULL)
{
return -1;
}
close(handle->fd);
return 0;
}
void
mbus_serial_data_free(mbus_handle *handle)
{
mbus_serial_data *serial_data;
if (handle)
{
serial_data = (mbus_serial_data *) handle->auxdata;
free(serial_data->device);
free(serial_data);
}
}
//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
int
mbus_serial_send_frame(mbus_handle *handle, mbus_frame *frame)
{
u_char buff[PACKET_BUFF_SIZE];
int len, ret;
if (handle == NULL || frame == NULL)
{
return -1;
}
if ((len = mbus_frame_pack(frame, buff, sizeof(buff))) == -1)
{
fprintf(stderr, "%s: mbus_frame_pack failed\n", __PRETTY_FUNCTION__);
return -1;
}
#ifdef MBUS_SERIAL_DEBUG
// if debug, dump in HEX form to stdout what we write to the serial port
printf("%s: Dumping M-Bus frame [%d bytes]: ", __PRETTY_FUNCTION__, len);
for (i = 0; i < len; i++)
{
printf("%.2X ", buff[i]);
}
printf("\n");
#endif
if ((ret = write(handle->fd, buff, len)) == len)
{
//
// call the send event function, if the callback function is registered
//
if (_mbus_send_event)
_mbus_send_event(MBUS_HANDLE_TYPE_SERIAL, buff, len);
}
else
{
fprintf(stderr, "%s: Failed to write frame to socket (ret = %d: %s)\n", __PRETTY_FUNCTION__, ret, strerror(errno));
return -1;
}
//
// wait until complete frame has been transmitted
//
tcdrain(handle->fd);
return 0;
}
//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
int
mbus_serial_recv_frame(mbus_handle *handle, mbus_frame *frame)
{
char buff[PACKET_BUFF_SIZE];
int len, remaining, nread, timeouts;
if (handle == NULL || frame == NULL)
{
fprintf(stderr, "%s: Invalid parameter.\n", __PRETTY_FUNCTION__);
return MBUS_RECV_RESULT_ERROR;
}
memset((void *)buff, 0, sizeof(buff));
//
// read data until a packet is received
//
remaining = 1; // start by reading 1 byte
len = 0;
timeouts = 0;
do {
//printf("%s: Attempt to read %d bytes [len = %d]\n", __PRETTY_FUNCTION__, remaining, len);
if ((nread = read(handle->fd, &buff[len], remaining)) == -1)
{
// fprintf(stderr, "%s: aborting recv frame (remaining = %d, len = %d, nread = %d)\n",
// __PRETTY_FUNCTION__, remaining, len, nread);
return MBUS_RECV_RESULT_ERROR;
}
// printf("%s: Got %d byte [remaining %d, len %d]\n", __PRETTY_FUNCTION__, nread, remaining, len);
if (nread == 0)
{
timeouts++;
if (timeouts >= 3)
{
// abort to avoid endless loop
fprintf(stderr, "%s: Timeout\n", __PRETTY_FUNCTION__);
break;
}
}
len += nread;
} while ((remaining = mbus_parse(frame, buff, len)) > 0);
if (len == 0)
{
// No data received
return MBUS_RECV_RESULT_TIMEOUT;
}
//
// call the receive event function, if the callback function is registered
//
if (_mbus_recv_event)
_mbus_recv_event(MBUS_HANDLE_TYPE_SERIAL, buff, len);
if (remaining != 0)
{
// Would be OK when e.g. scanning the bus, otherwise it is a failure.
// printf("%s: M-Bus layer failed to receive complete data.\n", __PRETTY_FUNCTION__);
return MBUS_RECV_RESULT_INVALID;
}
if (len == -1)
{
fprintf(stderr, "%s: M-Bus layer failed to parse data.\n", __PRETTY_FUNCTION__);
return MBUS_RECV_RESULT_ERROR;
}
return MBUS_RECV_RESULT_OK;
}