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modbus.c
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modbus.c
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/*
* Copyright (C) 2020 Thomas Steger
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
* Or, point your browser to http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
*/
#include <stdio.h>
#include <stdint.h>
#include <fcntl.h> /* File Control Definitions */
#include <termios.h>/* POSIX Terminal Control Definitions*/
#include <unistd.h> /* UNIX Standard Definitions */
#include <errno.h> /* ERROR Number Definitions */
#include <cstring>
#include <cstdlib>
#include <sys/ioctl.h>
#include <linux/serial.h>
#include <unistd.h>
#include <ctime>
#include <sys/types.h>
#include "modbus.h"
#include "common.h"
std::mutex cModbus::send_mtx;
const uint8_t cModbus::table_crc_hi[] = {
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
};
const uint8_t cModbus::table_crc_lo[] = {
0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06,
0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD,
0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,
0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A,
0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4,
0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3,
0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4,
0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,
0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29,
0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED,
0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60,
0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67,
0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,
0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,
0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E,
0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71,
0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,
0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,
0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B,
0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B,
0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,
0x43, 0x83, 0x41, 0x81, 0x80, 0x40
};
cModbus::cModbus(std::string device, int speed, int parity, int databit, int stopbit)
{
Mb_device = device;
Mb_speed = speed;
Mb_parity = parity;
Mb_databit = databit;
Mb_stopbit = stopbit;
Mb_ctx = -1;
Mb_debug = false;
Mb_connected = false;
int Mb_slave = 1;
}
cModbus::~cModbus()
{
Disconnect();
}
long cModbus::Timeout(int fd, long sec, long usec)
{
int rv;
fd_set set;
struct timeval timeout;
FD_ZERO(&set);
FD_SET(fd, &set);
if (sec == 0 && usec == 0)
{
rv = select(fd + 1, &set, NULL, NULL, NULL);
}
else
{
timeout.tv_sec = sec;
timeout.tv_usec = usec;
rv = select(fd + 1, &set, NULL, NULL, &timeout);
}
if(rv == -1)
{
printf("Modbus Error on Select\n"); /* an error accured */
return -1;
}
else if(rv == 0)
{
return -2; //Timeout
}
else
{
if (usec > 0 && sec == 0)
{
return (usec - timeout.tv_usec); //struct Timeval is modifield only on Linux on other OS it could be wrong.
}
else
{
return 1; //The Time of longer Timeouts does not matter e.g. Waiting for Beginning of new Requests.
}
}
}
int cModbus::Connect()
{
if (Mb_connected)
return Mb_ctx;
speed_t speed;
/* open port */
Mb_ctx = open(Mb_device.c_str(),O_RDWR | O_NOCTTY | O_NONBLOCK | O_NDELAY);
if(Mb_ctx<0)
{
LOG("cModbus:Open device failure\n") ;
return -1;
}
/* save old Terminal Settings */
if (tcgetattr (Mb_ctx, &oldSettings) < 0)
{
LOG("cModbus:Can't get terminal parameters");
return -1 ;
}
memset(&Mb_Settings, 0, sizeof(struct termios));
if (Mb_speed > 19200)
{
T1_5 = 750;
T3_5 = 1750;
}
else
{
T1_5 = 15000000/Mb_speed; // 1T * 1.5 = T1.5
T3_5 = 35000000/Mb_speed; // 1T * 3.5 = T3.5
}
//Overide Timeouts
if (TIMEOUT_T1_5 > 0)
T1_5 = TIMEOUT_T1_5;
if (TIMEOUT_T3_5 > 0)
T3_5 = TIMEOUT_T3_5;
switch (Mb_speed)
{
case 0:
speed = B0;
break;
case 50:
speed = B50;
break;
case 75:
speed = B75;
break;
case 110:
speed = B110;
break;
case 134:
speed = B134;
break;
case 150:
speed = B150;
break;
case 200:
speed = B200;
break;
case 300:
speed = B300;
break;
case 600:
speed = B600;
break;
case 1200:
speed = B1200;
break;
case 1800:
speed = B1800;
break;
case 2400:
speed = B2400;
break;
case 4800:
speed = B4800;
break;
case 9600:
speed = B9600;
break;
case 19200:
speed = B19200;
break;
case 38400:
speed = B38400;
break;
case 57600:
speed = B57600;
break;
case 115200:
speed = B115200;
break;
case 230400:
speed = B230400;
break;
default:
speed = B9600;
}
if ((cfsetispeed(&Mb_Settings, speed) < 0) ||
(cfsetospeed(&Mb_Settings, speed) < 0))
{
Disconnect();
LOG("cModbus: Error setting Baudrate");
return -1;
}
switch (Mb_databit)
{
case 7:
Mb_Settings.c_cflag = Mb_Settings.c_cflag | CS7;
break;
case 8:
default:
Mb_Settings.c_cflag = Mb_Settings.c_cflag | CS8;
break;
}
switch (Mb_parity)
{
case 1:
Mb_Settings.c_cflag = Mb_Settings.c_cflag | PARENB;
break;
case -1:
Mb_Settings.c_cflag = Mb_Settings.c_cflag | PARENB | PARODD;
break;
case 0:
default:
Mb_Settings.c_iflag = IGNPAR;
Mb_Settings.c_cflag &=~ PARENB;
break;
}
Mb_Settings.c_iflag &= ~ICRNL;
if (Mb_parity == 0) //parity off
{
Mb_Settings.c_iflag &= ~INPCK;
}
else
{
Mb_Settings.c_iflag |= INPCK;
}
if (Mb_stopbit==2)
Mb_Settings.c_cflag = Mb_Settings.c_cflag | CSTOPB;
/* Software flow control is disabled */
Mb_Settings.c_iflag &= ~(IXON | IXOFF | IXANY);
Mb_Settings.c_cflag = Mb_Settings.c_cflag | CLOCAL | CREAD;
Mb_Settings.c_oflag = 0;
Mb_Settings.c_lflag = 0; /*ICANON;*/
Mb_Settings.c_line = 0; //This field isn't used on POSIX systems
Mb_Settings.c_cc[VMIN]=0;
Mb_Settings.c_cc[VTIME]=0;
/* clean port */
tcflush(Mb_ctx, TCIFLUSH);
/* Get Notification if data arived TODO*/
//fcntl(fd, F_SETFL, FASYNC);
/* activate the settings port */
if (tcsetattr(Mb_ctx,TCSANOW,&Mb_Settings) <0)
{
LOG("cModbus: Can't set terminal parameters ");
return -1 ;
}
// Disable RTS Mode
int flags;
ioctl(Mb_ctx, TIOCMGET, &flags);
flags &= ~TIOCM_RTS;
ioctl(Mb_ctx, TIOCMSET, &flags);
/* clean I & O device */
tcflush(Mb_ctx,TCIOFLUSH);
Mb_connected = true;
return Mb_ctx;
}
void cModbus::Disconnect()
{
if (Mb_ctx >= 0)
{
tcsetattr(Mb_ctx,TCSANOW,&oldSettings);
close(Mb_ctx);
}
Mb_ctx = -1;
Mb_connected = false;
}
uint16_t cModbus::Crc16(uint8_t *buffer, int buffer_length)
{
uint8_t crc_hi = 0xFF; /* high CRC byte initialized */
uint8_t crc_lo = 0xFF; /* low CRC byte initialized */
unsigned int i; /* will index into CRC lookup */
/* pass through message buffer */
while (buffer_length--)
{
i = crc_hi ^ *buffer++; /* calculate the CRC */
crc_hi = crc_lo ^ table_crc_hi[i];
crc_lo = table_crc_lo[i];
}
return (crc_hi << 8 | crc_lo);
}
int cModbus::SendRequest(uint8_t *req, int req_lenght, uint8_t *resp)
{
std::lock_guard<std::mutex> lock(send_mtx);
usleep(T3_5); //Make sure we are in idle state
if (req_lenght > (MODBUS_RTU_MAX_ADU_LENGTH -2))
{
LOG("Modbus: Error Send Request to long\n");
return 0;
}
if (req_lenght < 1)
{
LOG("Modbus Request to send: %d nothing to send", req_lenght);
return 0;
}
int send_lenght = req_lenght;
uint8_t send_buffer[MODBUS_RTU_MAX_ADU_LENGTH];
uint16_t crc;
crc = Crc16(req, req_lenght);
memcpy(send_buffer, req, req_lenght);
MODBUS_SET_INT16_TO_INT8(send_buffer, send_lenght, crc);
send_lenght = send_lenght+2;
int send = 0;
int rc;
if (Mb_debug)
{
printf("Modbus Sending Request: ");
int n;
for (n=0; n<send_lenght; n++)
{
printf("<%02X>", send_buffer[n]);
}
printf("\n");
}
while (send < send_lenght)
{
rc = write(Mb_ctx, &send_buffer[send], (send_lenght - send));
if (rc <= 0)
{
LOG("Modbus Error on send rc=%d\n", rc);
return -1;
}
send = send + rc;
}
if (Mb_debug)
printf("%d Bytes send\n", send);
return Receive(resp, idle);
}
int cModbus::ReceiveRequest(uint8_t *req)
{
return Receive(req);
}
int cModbus::Receive(uint8_t *buffer, eState input_state)
{
uint8_t read_buffer[MODBUS_RTU_MAX_ADU_LENGTH];
int readbuffer_index = 0;
Mb_state = input_state;
char discardbyte;
bool Complete = false;
for (;;)
{
if (readbuffer_index == MODBUS_RTU_MAX_ADU_LENGTH)
break;
int rc;
if(Mb_state == initial)
{
rc = Timeout(Mb_ctx, 0, T3_5);
if (rc == -1)
{
LOG("Modbus: Error on Select()\n");
return -1;
}
else if (rc == -2) //Timeout
{
Mb_state = idle;
if (Mb_debug)
printf("Modbus Timeout expired switching from initial to idle State\n");
continue;
}
else if (rc >= 0)
{
if (read(Mb_ctx, &discardbyte, 1) > 0)
{
if (Mb_debug)
printf("Modbus beginning of request not found discard Byte: %02X\n", discardbyte);
continue;
}
else
{
LOG("Modbus: Error on Read and discard Byte\n");
return -1;
}
}
}
if(Mb_state == idle)
{
rc = Timeout(Mb_ctx, 5, 0); //Block until a byte receives for reading Max 5 Seconds
if (rc == -1)
{
LOG("Modbus: Error on Select()\n");
return -1;
}
else if (rc == -2) //Timeout
{
if (Mb_debug)
printf("Modbus Timeout expired in idle state\n");
return 0;
}
else if (rc >= 0)
{
if (read(Mb_ctx, &read_buffer[readbuffer_index], 1) == 1)
{
Mb_state = processing; //first byte received switching to processing
if (Mb_debug)
printf("Modbus new Request received: <%02X>", read_buffer[readbuffer_index]);
readbuffer_index++;
continue;
}
else
{
LOG("Modbus: Error on Read Byte\n");
return -1;
}
}
}
if (Mb_state == processing)
{
rc = Timeout(Mb_ctx, 0, T3_5); //After Timeout T3_5 a Full Request shold be received
if (rc == -1)
{
LOG("Modbus: Error on Select()\n");
return -1;
}
else if (rc == -2) //Timeout
{
if (Mb_debug)
{
printf("\n");
printf("%d bytes received\n", readbuffer_index);
}
Mb_state = idle;
Complete = true;
break;
}
else if (rc > T1_5) //Inter Char Timout expired Request uncomplete
{
if (Mb_debug)
printf("Inter Char Timeout expired Request uncomplete discarding! Timeout: %d\n", rc);
readbuffer_index = 0;
Mb_state = initial;
continue;
}
else
{
if (read(Mb_ctx, &read_buffer[readbuffer_index], 1) == 1)
{
if (Mb_debug)
printf("<%02X>", read_buffer[readbuffer_index]);
readbuffer_index++;
continue;
}
else
{
LOG("Modbus: Error on Read Byte\n");
return -1;
}
}
}
}
if (Complete && readbuffer_index > 3)
{
if (read_buffer[0] != Mb_slave)
{
if (Mb_debug)
printf("Modbus Request for Slave ID: %d not %d\n", read_buffer[0], Mb_slave);
return 0;
}
uint16_t crc;
uint16_t crc_received;
crc = Crc16(read_buffer, (readbuffer_index-2));
crc_received = MODBUS_GET_INT16_FROM_INT8(read_buffer, (readbuffer_index-2));
if (crc_received == crc)
{
memcpy(buffer, read_buffer, (readbuffer_index));
return (readbuffer_index);
}
else
{
if (Mb_debug)
printf("Modbus CRC Received: %04X != CRC Caculated: %04X\n", crc_received, crc);
return 0;
}
}
else
{
return 0;
}
}
int cModbus::SendConfirmation(uint8_t *conf, int conf_lenght)
{
if (conf_lenght > (MODBUS_RTU_MAX_ADU_LENGTH -2))
{
LOG("Modbus: Error Confirmation to long\n");
return 0;
}
int send_lenght = conf_lenght;
uint8_t send_buffer[MODBUS_RTU_MAX_ADU_LENGTH];
uint16_t crc;
crc = Crc16(conf, conf_lenght);
memcpy(send_buffer, conf, conf_lenght);
MODBUS_SET_INT16_TO_INT8(send_buffer, send_lenght, crc);
send_lenght = send_lenght+2;
int send = 0;
int rc;
if (Mb_debug)
{
printf("Modbus Sending Confirmation: ");
int n;
for (n=0; n<send_lenght; n++)
{
printf("<%02X>", send_buffer[n]);
}
printf("\n");
}
while (send < send_lenght)
{
rc = write(Mb_ctx, &send_buffer[send], (send_lenght - send));
if (rc <= 0)
{
LOG("Modbus Error on send\n");
return 0;
}
send = send + rc;
}
if (Mb_debug)
printf("%d Bytes send\n", send);
return send;
}