gistfile1.txt

/* 
This file contains codes mostly developed by Dr.Ken Christensen. Email: christen@csee.usf.edu 
 http://www.csee.usf.edu/~christen/tools/toolpage.html


 class : Computer Networks
 */
/* Code is readable and therefore comments are added when absolutely needed */

/* Header Files for time, sockets, IO and String */

#include <sys/time.h>
#include <sys/timeb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>

#define NAME_OF_HOST "grad.csee.usf.edu"
#define PORT_NUMBER 8081 // Port number associated with the Server
#define GET_HTTP_REQUEST "GET /2.html HTTP/1.0\n\n" // HTTP request
#define RESULTS_FILE_NAME "CenterCourt_Large_AM.xls"
#define CLIENT_BUFFER_SIZE 4096

int main(void)
{

    struct hostent* host; // Structure for gethostbyname()
    struct in_addr address; // Structure for Internet address
    char host_ip[256]; // Host IP address

    int client_s; // Client socket descriptor
    struct sockaddr_in server_addr; // Server Internet address
    char out_buf[CLIENT_BUFFER_SIZE]; // Output buffer for data
    char in_buf[CLIENT_BUFFER_SIZE]; // Input buffer for data
    int retcode; // Return code

    FILE* fp = fopen(RESULTS_FILE_NAME, "w"); // FILE I/O
    int experiments; // Number of experiments
    int iterations; // Number of download attempts in a single Experiment
    double total; // Total download time
    struct timeb start, stop; //Timer
    double elapsed;

    for (experiments = 1; experiments <= 10; experiments++) {
        if (experiments != 1)
            sleep(5); // Waiting time between each experiment
        total = 0;
        for (iterations = 1; iterations <= 10; iterations++) {
            sleep(0.1); //Interval between each iteration(download attempt of the current experiment)
            double total_downloadtime = 0;
            ftime(&start); //Timer start

            host = gethostbyname(NAME_OF_HOST); //DNS resolve
            if (host == NULL)
                printf("IP address for '%s' could not be found\n", NAME_OF_HOST);
            else {
                memcpy(&address, host->h_addr, 4);
                strcpy(host_ip, (char*)inet_ntoa(address));
            }

            client_s = socket(AF_INET, SOCK_STREAM, 0);
            if (client_s < 0) {
                printf("*** ERROR - socket() failed \n");
                goto ex;
            }
            server_addr.sin_family = AF_INET; // Address family to use
            server_addr.sin_port = htons(PORT_NUMBER); // Port num to use
            server_addr.sin_addr.s_addr = inet_addr(host_ip); // IP address to use

            retcode = connect(client_s, (struct sockaddr*)&server_addr, sizeof(server_addr)); // Connect
            if (retcode < 0) {
                printf("*** ERROR - connect() failed\n");
                goto ex;
            }

            strcpy(out_buf, GET_HTTP_REQUEST);
            retcode = send(client_s, out_buf, (strlen(out_buf) + 1), 0); //Send the HTTP Get request
            if (retcode < 0) {
                printf("*** ERROR - send() failed \n");
                goto ex;
            }
            retcode = recv(client_s, in_buf, CLIENT_BUFFER_SIZE + 1, 0);

            while ((retcode > 0) || (retcode == -1)) {
                retcode = recv(client_s, in_buf, CLIENT_BUFFER_SIZE + 1, 0);
                if (strlen(in_buf) == 0) {
                    break;
                }
                if (retcode < 0) {
                    printf("*** ERROR - recv() failed \n");
                    break;
                }
            }
            ftime(&stop); //Stop timer
            total_downloadtime = ((double)stop.time + ((double)stop.millitm * 0.001)) //Measure download time
                - ((double)start.time + ((double)start.millitm * 0.001));

            fprintf(fp, "\n%d\t%7.3f", iterations, total_downloadtime);
            printf("%d\t%7.3f\n", iterations, total_downloadtime); //write to output file
            strcpy(out_buf, "Message: Closing Connection");
            retcode = send(client_s, out_buf, (strlen(out_buf) + 1), 0); //Send message to server informing intent to close
            if (retcode < 0) {
                printf("*** ERROR - send() failed \n");
                goto ex;
            }
            retcode = close(client_s); //get the response for the close request
            if (retcode < 0) {
                printf("*** ERROR - close() failed \n");
                goto ex;
            }
            total = total + total_downloadtime; // Add the total download time for the whole experiment
        }
        double Mean;
        Mean = total / 10;
        fprintf(fp, "\t%7.3f\n", Mean); //write results to file
        printf("experiment %d finished: Mean is %7.3f\n", experiments, Mean);
    }
    fclose(fp); //Close the result file

ex: //Exit here when error happens
    fflush(stdin);
    return 0;
}