[RCOM] Transmitter

/*Non-Canonical Input Processing*/

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <stdio.h>
#include <string.h>
#include <signal.h>

#define BAUDRATE B38400
#define MODEMDEVICE "/dev/ttyS"
#define _POSIX_SOURCE 1 /* POSIX compliant source */
#define FALSE 0
#define TRUE 1
#define F 0x7e
#define A 0x03
#define S 0x03
#define U 0x07
#define I0 0x00
#define I1 0x40

#define RECEIVER 0
#define TRANSMITTER 1

volatile int STOP=FALSE;

int llopen(int porta, int flag){
  unsigned char setup[5];
  setup[0]=F;
  setup[1]=A;
  setup[2]=S;
  setup[3]=setup[1]^setup[2];
  setup[4]=F;
  char buffer[1];
  char gate[10]=MODEMDEVICE;

  sprintf(buffer, "%d",porta);

  strcat(gate, buffer);

  printf("%s \n",gate );



  int fd,c, res;



  struct termios oldtio,newtio;
  int i=0, sum = 0, speed = 0;


  fd = open(gate, O_RDWR | O_NOCTTY | O_NONBLOCK);
  if (fd <0) { exit(-1); }

  if ( tcgetattr(fd,&oldtio) == -1) { /* save current port settings */
    perror("tcgetattr");
    exit(-1);
  }

  bzero(&newtio, sizeof(newtio));
  newtio.c_cflag = BAUDRATE | CS8 | CLOCAL | CREAD;
  newtio.c_iflag = IGNPAR;
  newtio.c_oflag = 0;

  /* set input mode (non-canonical, no echo,...) */
  newtio.c_lflag = 0;
  newtio.c_cc[VTIME]    = 3;   /* inter-character timer unused */
  newtio.c_cc[VMIN]     = 1;   /* blocking read until 5 chars received */

  tcflush(fd, TCIOFLUSH);

  if ( tcsetattr(fd,TCSANOW,&newtio) == -1) {
    perror("tcsetattr");
    exit(-1);
  }

  printf("New termios structure set(Receiving Message)\n");

    unsigned char msg;
    char UA[5];
    int aux=0;
    int counter=0;
    int sendAgain=1;
    int state;
    int done=0;
    int msgsent=0;
    int res2;


  for(counter ; counter < 3; counter++){
    printf("%s%d\n" ,"Sending data. Try# " , counter+1);
    sleep(3);
    res = write(fd,setup,5);
    state=0;
    while (state < 5 )
    {
      res2 = read(fd,&msg,1);
      if(res2 == -1){
        break;
      }
      else msgsent=1;

      switch (state)
      {
        case 0:
          if (msg == F){
            UA[state]=msg;
            state++;
          }

          break;
        case 1:
          if (msg == A){
          UA[state]=msg;
          state++;
          }

          else if(msg != A && msg !=F) state--;

          break;

        case 2:
          if (msg == U){
            UA[state]=msg;
            state++;
          }

          else if(msg == F) state--;

          else state=0;

          break;
        case 3:
          if (msg == (A^U)){
            UA[state]=msg;
            state++;
          }

          else state=0;

          break;
        case 4:
          if (msg == F){
            UA[state]=msg;
            state++;
            done=1;
          }

          else state=0;

          break;
      }
    }

    if(done) break;
  }

  if(msgsent == 0 ) {
    printf("Could not send any message. UA not received\n");
    return -1;
  } else {
    printf("UA received sucessfuly\n");
  }

  if ( tcsetattr(fd,TCSANOW,&oldtio) == -1) {
    perror("tcsetattr");
    exit(-1);
  }
  close(fd);
  return fd;
}

llwrite(int fd,char* buffer, int length){

  //PRIMEIRA TRAMA
  char msg[6+length];
  msg[0]=F;
  msg[1]=A;
  msg[2]=I0;
  msg[3]=msg[1]^msg[2];
  //stuffing da msg <-
  int i=4;
  for(;i<length+4; i++){
    msg[i]=buffer[i-4];
  }

  int j=1;
  char temp = buffer[0];
  for(; j<length; j++){
    temp=temp^buffer[j];
  }
  msg[length+5]=temp;
  msg[length+6]=F;



}

void main(int argc, char** argv){
  system("clear");
  printf("llopenTransmitter Running\n");
  llopen(0,TRANSMITTER);
}