How can I bypass websites that block direct connections? - c

Question

I'm trying to access the website https://www.000webhost.com with C sockets:
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
int main(int argc, char** argv) {
struct sockaddr_in servaddr;
struct hostent *hp;
int sock_id;
char message[1024*1024];
char request[] = "GET / HTTP/1.1\n" "From: ...\n";
//get a socket
if((sock_id = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
fprintf(stderr,"Couldn't get a socket.\n");
exit(EXIT_FAILURE);
}else {
fprintf(stderr,"Got a socket.\n");
}
memset(&servaddr,0,sizeof(servaddr));
//get address
if((hp = gethostbyname("000webhost.com")) == NULL) {
fprintf(stderr,"Couldn't get an address.\n");
exit(EXIT_FAILURE);
}else {
fprintf(stderr,"Got an address.\n");
}
memcpy((char *)&servaddr.sin_addr.s_addr, (char *)hp->h_addr, hp->h_length);
//port number and type
servaddr.sin_port = htons(80);
servaddr.sin_family = AF_INET;
//connect
if(connect(sock_id, (struct sockaddr *)&servaddr, sizeof(servaddr)) != 0) {
fprintf(stderr, "Couldn't connect.\n");
}else {
fprintf(stderr,"Got a connection.\n");
}
//request
write(sock_id,request,strlen(request));
//response
read(sock_id,message,1024*1024);
fprintf(stdout,"%s",message);
return 0;
}
If I change the request[] array from "GET / HTTP/1.1\n" "From: ...\n" to "GET / HTTP/1.1\n" "Host: https://www.000webhost.com" "From: ...\n" (therefore removing the direct-IP adress from the request), I still get the error Error 1003. Direct IP access not allowed. Is there some other part of the request that I need to modify? What else do I need to do?

Answer 1

Your request is malformed:
Each line needs to be terminated by \r\n, not just \n. (Some web servers will let you get away with \n, but I have no idea whether that'll work on 000webhost.)
Every header needs a \r\n after it. The modified code you mention in the last paragraph is missing a \r\n at the end of the Host header.
The Host header needs to just be a hostname (e.g, "Host: example.com"). Don't include http://.