rttclient.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <time.h>
// importing files and time lib is used to measure time interval
int main(){

  char *ip = "127.0.0.1";
  int port = 5565;
// initializing
  int sock;
  struct sockaddr_in addr;
  socklen_t addr_size;
	//initially buffer of size 100 bytes you can change it to get different packet size.
  char buffer[100];
  int n;
// TCP socket creation and for UDP use SOCK_DGRAM
  sock = socket(AF_INET, SOCK_STREAM, 0);
  if (sock < 0){
    perror("[-]Socket error");
    exit(1);
  }
  printf("[+]TCP server socket created.\n");

  memset(&addr, '\0', sizeof(addr));
  addr.sin_family = AF_INET;
  addr.sin_port = port;
  addr.sin_addr.s_addr = inet_addr(ip);

  connect(sock, (struct sockaddr*)&addr, sizeof(addr));
  printf("Connected to the server.\n");
  int i =1;
  printf("Measurements when buffer size is 100 bytes\n");
//two times sending the packets to measure average rtt.
while(i<=2){

  bzero(buffer,100);
  strcpy(buffer, "HELLO, THIS IS CLIENT.");
  clock_t t;
  // time starts when sender sends message
	t = clock();
  send(sock, buffer, strlen(buffer), 0);
	  bzero(buffer, 100);
	recv(sock, buffer, sizeof(buffer), 0);
	 t = clock() - t; 
	 // time interval calculation in second
    double time_taken = ((double)t)/CLOCKS_PER_SEC;
	 // time ends when message is received back.
  printf("this is iteration number%s\n", buffer);
  printf("time for this message is %f\n\n", time_taken);
  ++i;
  }
  
  close(sock);
  printf("Disconnected from the server.\n");
  return 0;

}