Thread: Determining Latency of Web Sites

I am writing a simple program that connects a socket to, say google, and then waits for a response. Basically, I am determining the latency of web sites over a 24 hour period. I am doing something wrong because my writes aren't working. I use port 80 and copy GET / http/1.0\r\n\r\n into a buffer and write it to google. My program seems to be sticking in the write process, and I have no ideas if the read will work or not. I am using AF_INET and SOCK_STREAM to create my socket file descriptors. Any ideas?

Here is my code:

Code:

#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

void error(char *msg)
{
    perror(msg);
    exit(0);
}

int main(int argc, char *argv[])
{
    int sockfd, portno, n;
    struct sockaddr_in serv_addr;
    struct hostent *server;

    char buffer[256];
    if (argc < 2) {
       fprintf(stderr,"usage %s hostname\n", argv[0]);
       exit(0);
    }
    portno = 80;
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0)
        error("ERROR opening socket");
    server = gethostbyname(argv[1]);
    if (server == NULL) {
        fprintf(stderr,"ERROR, no such host\n");
        exit(0);
    }
    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    bcopy((char *)server->h_addr,
         (char *)&serv_addr.sin_addr.s_addr,
         server->h_length);
    serv_addr.sin_port = htons(portno);
    if (connect(sockfd,&serv_addr,sizeof(serv_addr)) < 0)
        error("ERROR connecting");
    strcpy(buffer, "GET / http/1.0\r\n\r\n");
    bzero(buffer,256);
    fgets(buffer,255,stdin);
    n = write(sockfd,buffer,strlen(buffer));
    if (n < 0)
         error("ERROR writing to socket");
    printf("wrote to site");
    bzero(buffer,256);
    n = read(sockfd,buffer,255);
    if (n < 0)
         error("ERROR reading from socket");
    printf("%s\n",buffer);
    return 0;
}

All I need is for google to get my request and send back one line. I am determining the latency over a 24 hour period.

Thank you! Next time I will check my code a little closer before posting.