Connection bluetooth commande AT

#include <SoftwareSerial.h>   //Software Serial Port
#define RxD 2
#define TxD 3

#define MASTER 1    //change this macro to define the Bluetooth as Master or not 

SoftwareSerial blueToothSerial(RxD, TxD); //the software serial port

char recv_str[100];

void setup()
{
  Serial.begin(115200);   //Serial port for debugging
  pinMode(RxD, INPUT);    //UART pin for Bluetooth
  pinMode(TxD, OUTPUT);   //UART pin for Bluetooth
  Serial.println("\r\nPower on!!");
  while (setupBlueToothConnection() != 0);  //initialize Bluetooth
  //this block is waiting for connection was established.
  while (1)
  {
    if (recvMsg(1000) == 0)
    {
      if (strcmp((char *)recv_str, (char *)"OK+CONB") == 0)
      {
        Serial.println("OK1");
        Serial.println("connected\r\n");
        break;
      }
    }
    delay(2000);
  }
}

void loop()
{
#if MASTER  //central role
  //in master mode, the bluetooth send message periodically.
  delay(400);
  Serial.println("send: hi");
  blueToothSerial.print("je suis opérationel");
  delay(2000);

  //get any message to print
  if (recvMsg(1000) == 0)
  {
    Serial.print("recv: ");
    Serial.print((char *)recv_str);
    Serial.println("");

  }
#else   //peripheral role
  delay(200);
  Serial.println("OK2");
  //the slave role only send message when received one.
  if (recvMsg(1000) == 0)
  {
    Serial.println("OK3");
    Serial.print("recv: ");
    Serial.print((char *)recv_str);
    Serial.println("");
    Serial.println("send: hello");
    blueToothSerial.print("hello");//return back message
  }
#endif
}

//used for compare two string, return 0 if one equals to each other
int strcmp(char *a, char *b)
{
  unsigned int ptr = 0;
  while (a[ptr] != '\0')
  {
    if (a[ptr] != b[ptr]) return -1;
    ptr++;
  }
  return 0;
}

//configure the Bluetooth through AT commands
int setupBlueToothConnection()
{
#if MASTER
  Serial.println("this is MASTER\r\n");
#else
  Serial.println("this is SLAVE\r\n");
#endif

  Serial.print("Setting up Bluetooth link\r\n");
  delay(3500);//wait for module restart

  //send command to module in different baud rate
  while (1)
  {
    delay(500);
    blueToothSerial.begin(9600);
    delay(500);
    Serial.print("try 9600\r\n");
    if (sendBlueToothCommand("AT") == 0)
      break;
    delay(2000);
    blueToothSerial.begin(115200);
    delay(2000);
    Serial.print("try 115200\r\n");
    if (sendBlueToothCommand("AT") == 0)
      break;
  }
  blueToothSerial.begin(9600);
#if MASTER
  sendBlueToothCommand("AT+ROLB0");//set to master mode
#else
  sendBlueToothCommand("AT+ROLB1");
  sendBlueToothCommand("AT+MODE1");
#endif
  delay(3500);//wait for module restart
  sendBlueToothCommand ("AT+AUTH?");
  delay(2000);
  if (sendBlueToothCommand("AT") != 0) return -1; //detect if the module exists
  Serial.print("Setup complete\r\n\r\n");
  sendBlueToothCommand ("AT+RSSB?"); // interroger RSSI
  delay(2000);
  sendBlueToothCommand ("AT+RSSE?");
  delay(2000);
  return 0;
}

//send command to Bluetooth and return if there is a response
int sendBlueToothCommand(char command[])
{
  Serial.print("send: ");
  Serial.print(command);
  Serial.println("");

  blueToothSerial.print(command);
  delay(200);

  if (recvMsg(200) != 0) return -1;

  Serial.print("recv: ");
  Serial.print(recv_str);
  Serial.println("");
  return 0;
}

//receive message from Bluetooth with time out
int recvMsg(unsigned int timeout)
{
  //wait for feedback
  unsigned int time = 0;
  unsigned char num;
  unsigned char i;

  //waiting for the first character with time out
  i = 0;
  while (1)
  {
    delay(50);
    if (blueToothSerial.available())
    {
      recv_str[i] = char(blueToothSerial.read());
      i++;
      break;
    }
    time++;
    if (time > (timeout / 50)) return -1;
  }

  //read other characters from uart buffer to string
  while (blueToothSerial.available() && (i < 9000))
  {
    recv_str[i] = char(blueToothSerial.read());
    i++;
  }
  recv_str[i] = '\0';

  return 0;
}