Connection refused while trying to retrieve html from http website using sockets in C

Question

I have made a pretty simple http client which would retrieve html from http website and print it. But there seems to be some problem while using connect() function.Using perror() I found that it is giving connection refused error.

This is my code

#include <string.h>
#include <stdio.h>
#include <iostream>

#include <sys/socket.h>
#include <unistd.h>
#include <sys/types.h>

#include <netinet/in.h>
#include <arpa/inet.h>

int main(int argc, char *argv[])
{
    char *address;
    address = argv[1];

    int c_socket = socket(AF_INET, SOCK_STREAM, 0);

    struct sockaddr_in URLaddress;

    URLaddress.sin_family = AF_INET;
    URLaddress.sin_port = htons(80);
    inet_pton(0,address,&URLaddress.sin_addr.s_addr);
    int con = connect(c_socket, (struct sockaddr*) &URLaddress, 
    sizeof(URLaddress));

    perror("error");

    return 0;
}

This is the input

151.101.13.5

This is the output

error: Connection refused

I am passing IP of website as input.

I have seen all other similar questions but didn't get any answer as how to fix this because this keeps happening with every website I try my program with. Please tell how to resolve this.

Paul Ogilvie · Accepted Answer · 2018-10-17 12:26:19Z

1

The following version of the code works on Windows/MSC:

int test(void)
{
    char *address;
    int c_socket, con;
    struct sockaddr_in URLaddress;
    char request[] = "GET / HTTP/1.1\r\n\r\n";
    char response[4096];
    WORD wVersionRequested;
    WSADATA wsaData;

    wVersionRequested = MAKEWORD( 2, 2 );

    address = "151.101.13.5";

    if (WSAStartup (wVersionRequested, &wsaData)!= 0) {
        printf("DLL not found\n");
        return -1;
    }
    if ((c_socket = socket(AF_INET, SOCK_STREAM, 0)) ==  INVALID_SOCKET ) {
        printf("socket error: %d\n", WSAGetLastError());
        return -1;
    }

    URLaddress.sin_family = AF_INET;
    URLaddress.sin_port = htons(80);
    URLaddress.sin_addr.s_addr= inet_addr(address);
    con = connect(c_socket, (struct sockaddr*) &URLaddress, sizeof(URLaddress));

    send(c_socket, request, strlen(request), 0);
    recv(c_socket, response, sizeof(response), 0);
    WSACleanup();

    printf ("%s\n",response);

    return 0;
}

The repsonse is:

<title>Fastly error: unknown domain </title>
</head>
<body>
<p>Fastly error: unknown domain: . Please check that this domain has been added to a service.</p>
<p>Details: cache-fra19128-FRA</p></body></html>5¸`¡qu

answered Oct 17, 2018 at 12:26

Paul Ogilvie

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2 Comments

Shobhit Over a year ago

although i am on linux mint but i have tried changing this line inet_pton(0,address,&URLaddress.sin_addr.s_addr); with //inet_pton(0,address,&URLaddress.sin_addr.s_addr); and it is now at least connecting and giving some sort of output error: Success GET / HTTP/1.1 which is still not satisfactory but better than before.Thanks

Paul Ogilvie Over a year ago

Success as the output of perror means there is no error. Did you print response?

Luis Colorado · Accepted Answer · 2018-10-22 11:15:20Z

0

inet_pton(3) requires a first parameter to specify the address family and you have passed 0 for it (which is not the same as AF_INET), and you had to pass AF_INET, in accordance of the protocol family you are using.

inet_pton(3) is a protocol family independent conversion routine, but it needs to know what is the actual used to be able to convert addresses properly.

By the way, is a server listening on the requested address and port? have you tested that a browser is capable of getting something from that address before running your program?

answered Oct 22, 2018 at 11:15

Luis Colorado

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