/* typical header files */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

/* sockets/internet header files */
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int my_port = 60001;

int main(int argc, char* argv[]){

  if( argc > 1 ) my_port += atoi(argv[1]);

  int myListenSocket, clientSocket;
  struct sockaddr_in  myAddr, clientAddr;
  int i, addrSize, bytesRcv;

  char buffer[300];
  char buffer2[300];

/* create socket */
  myListenSocket = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
  if (myListenSocket < 0) {
    printf("eek! couldn't open socket\n");
    exit(-1);
  }


/* setup my server address */
  memset(&myAddr, 0, sizeof(myAddr));

  myAddr.sin_family      = AF_INET;
  myAddr.sin_port        = htons((unsigned short) my_port);
  myAddr.sin_addr.s_addr = htonl(INADDR_ANY);


/* bind my listen socket */
  i = bind(myListenSocket,                // socket descriptor  
           (struct sockaddr *) &myAddr,   // pointer to sockaddr
           sizeof(myAddr));               // size of said sockaddr
  if (i < 0) {
    printf("eek! couldn't bind socket\n");
    exit(-1);
  }


/* listen */
  i = listen(myListenSocket, 5);
  if (i < 0) {
    printf("eek! couldn't listen\n");
    exit(-1);
  }


/* wait for connection request */
  addrSize = sizeof(clientAddr);

  clientSocket = accept(myListenSocket,
                        (struct sockaddr *) &clientAddr,
                        &addrSize);
  if (clientSocket < 0) {
    printf("eek! couldn't accept the connection\n");
    exit(-1);
  }

/* read message from client and do something with it */
  while (1) {
    bytesRcv = recv(clientSocket, buffer, sizeof(buffer), 0);
    buffer[bytesRcv] = 0;
    strcpy(buffer2,buffer);

    for( int i=0; i<bytesRcv; i+=1)  buffer[i] += 1;
    send(clientSocket, buffer, sizeof(buffer), 0);

    printf("received.... : %s\n", buffer);
    fflush(stdout);

	if(strcmp(buffer2,"quit") == 0)
      break;
  } 

/* close sockets */

  close(myListenSocket);
  close(clientSocket);

  return 0;
}