CODEWITHSUNDEEP
csocketshttpnetwork-programming
user2497585
user2497585

Reputation:

Non-ASCII bytes received from browser in C socket

I've managed to create a C server that accepts a connection from a web browser, however, the HTTP request I receive from the socket is random bytes that I can't seem to convert to ASCII values, as below:

\00\00\00\00\00\00\00\00\A9Ag_\BD\00\00\00\00\00\00\00\00\00\00\BD\88_\BD\00\00\C0\B4\88_\BD\00\00<\A7f_\BD\00\00\F0,+_\BD\00\00\A4f_\BD\00\00\00\00\00\00\00\00\00\9D\00\00\00\00\00\00\00\00\00\00\00\000b0\D8\FF\00\00\90a0\D8\FF\00\00\BD\88_\BD\00\00\C0\E5\88_\BD\00\00\F8و_\BD\00\00\00\00\00\00\00\00\00\A9Ag_\BD\00\00\00\00\00\00\00\00\00\00\BD\88_\BD\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\FF\00\00\F8و_\BD\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\F8\E7\88_\BD\00\00(`\00\00\00\00\00\00\00\00\00\00\00\00\00\C0\E5\88_\BD\00\00\F0`0\D8\FF\00\00\E0`0\D8\FF\00\00\87\F0\96|\00\00\00\00\00\00\80\C0\00\00\00\00\00\90-Ͼz\FF<\A7f_\BD\00\00\FF\FF\FF\FF\00\00\00\00\00 *_\BD\00\00\D0++_\BD\00\00\C0\B4\88_\BD\00\00 <\00\00\00\00\00\C0\B4\88_\BD\00\00\B0b0\D8\FF\00\00\FD\A6=_\BD\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\C0\E1?\D8\FF\00\00\00\00\00\00 \00\00\00|6g_\BD\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00c0\D8\FF\00\00\00\00\00\00\00\00\00&\B0be\00\00\00\00*?g_\BD\00\00\00\00\00\00\00\00\00\00&\00\00\00\00\00\00\00\C0\8A\95\00\00\00\00`\E1?\D8\FF\00\00\00\00\00\BD\00\00\00\00\00\00\00\00\00\00`\E1?\D8\FF\00\00|6g_\BD\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00pc0\D8\FF\00\00\00\00\00\00\00\00\00.N=\F6\00\00\00\00\80>g_\BD\00\00\00\00\00\00\00\00\00\00.\00\00\00\00\00\00\008\F5\D8\00\00\00\00]*_\BD\00\00[*_\BD\00\00\00\00\00\00\00\00\00]*_\BD\00\00\C8c0\D8\FF\00\00\A0c0\D8\FF\00\00 !+_\BD\00\00\80\EB\88_\BD\00\00\F8\E7\88_\BD\00\00\00\00\00\00\00\00\00\00\BA\88_\BD\00\00\C0\B4\88_\BD\00\00\D4@\00\00\00\00\00\F0,+_\BD\00\00\80@\00\00\00\00\00\00\00\00\00\00\00\00+\00\00\00\00\00h\E2\88_\BD\00\008d0\D8\FF\00\00d0\D8\FF\00\00\BA\88_\BD\00\00\C0\E5\88_\BD\00\00h\E2\88_\BD\00\00\00\00\00\00\00\00\00\A9Ag_\BD\00\00\00\00\00\00\00\00\00\00\BA\88_\BD\00\00\00\00\00\BD\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00h\E2\88_\BD\00\00\D8\E1?\D8\FF\00\00\F8\E7\88_\BD\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\C0\E5\88_\BD\00\00pc0\D8\FF\00\00`c0\D8\FF\00\00.N=\F6\00\00\00\00v\00\00\00\00\00\00\C2\00\00\00\00\00\00\00\D4@\00\00\00\00\00\F

To be fair, when in terminal, it does seem to "resemble" an HTTP request, however, I don't know what is failing :(

Any help is appreciated...

#include <netinet/in.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>

#define BUFLEN 1024
#define PORT 8080

/*
 * Server.c
 *
 * Accept connections from a client
 *
 */

int main() {
    /* Useful Declarations */
    int fd, backlog, connfd;
    char buf[BUFLEN];
    struct sockaddr_in addr, cliaddr;
    socklen_t cliaddrlen;
    ssize_t rcount, i;

    /* IPv4 Declarations */
    addr.sin_addr.s_addr    = INADDR_ANY;
    addr.sin_family         = AF_INET;
    addr.sin_port           = htons(PORT);

    /* Create socket or return error */
    if ((fd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        fputs("Unable to create a socket\n", stderr);
        return -1;
    }

    /* Bind socket to port or return error */
    if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) == -1) {
        fputs("Unable to bind socket to port\n", stderr);
        return -1;
    }

    backlog = 1;

    /* Start listening to port or return error */
    if (listen(fd, backlog) == -1) {
        fputs("Unable to listen to port\n", stderr);
        close(fd);
        return -1;
    }

    cliaddrlen = sizeof(cliaddr);

    /* Await for connection, or return error */
    if ((connfd = accept(fd, (struct sockaddr *) &cliaddr, &cliaddrlen)) == -1) {
        fputs("Unable to accept connection\n", stderr);
        close(fd);
        return -1;
    }

    /* Read up to 1500 bytes from socket or error*/
    if ((rcount = read(fd, buf, BUFLEN)) == -1) {
        fputs("Error occurred while reading from socket\n", stderr);
        printf("Error Number: %d\n", errno);

        for (i = 0; i < BUFLEN; i++)
            printf("%c", buf[i]);

        return -1;
    }

    close(fd);
    fputs("Socket closed\n", stdout);
    return 0;
}

I am aware that this will only print when the connection is closed by the client prematurely, but I can cross that bridge later when I come to it :)

Upvotes: 0

Views: 145

Answers (1)

ldx
ldx

Reputation: 4074

Three things:

  • You should be using connfd, not fd to read from - fd is the original listening socket.
  • When printing out your buffer, use rcount to see how many bytes you got.
  • This also means that it only makes sense to print out your buffer if rcount > 0.

Upvotes: 1

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