/*
**++
**  FACILITY:   Remote URL Activator
**
**  MODULE DESCRIPTION:
**
**      This is a M$ Windoze-part of the "remote UTL activator", contains a code to receive
**      packet with URL to start a default browser wih it.
**
**  AUTHOR:     Ruslan R. Laishev
**              Copyright 2009, Ruslan R. Laishev
**
**      Build:
**              cl url_exec.c /ML
**
**      Using:
**		URL_Exec <shared> [<port>]
**		Example:
**		c:\>URL_Exec trhdfh#$%gvbv 8133
**
**  MODIFICATION HISTORY:
**
**      7-JUL-2009     RRL     Initial coding.
**--
*/

#include	<conio.h>
#include	<windows.h>
#include	<winsock.h>
#include	<stdio.h>
#include	<stdlib.h>
#include	<errno.h>
#include	<string.h>

#include	"md5.h"

#pragma	comment(lib,	"ws2_32.lib")
#pragma	comment(lib,	"shell32.lib")

struct  pdu     {
        unsigned short  len;
        unsigned char   hash[16],
                        url[1];
                };

int main(int argc, char* argv[])
{
int	rc = 0,secretlen = 0, buflen, sock = 0;
char *secret, buf [ 1024], cmd [1024],hash [16];
WSADATA	 wsadata;
struct pdu *ptr = (struct pdu *) &buf;
short   port = 8133;
struct sockaddr_in addr;
MD5_CTX md5;

	/*
	** Dumb checking for input arguments
	*/
	if ( argc < 2 )
		{
		printf("Usage:\n URL_Exec <shared> [<port>]\n");
		return  -1;
		}

	/*
	** Input arguments: shared secret & port
	*/
	secret = argv[1];
	secretlen = strlen(secret);
	printf("Secret (%u): %.*s\n",secretlen,secretlen,secret);

	if ( (argc > 2) && argv[2] )
		port = atoi(argv[2]);

	/*
	** Create a UDP socket, start listening...
	*/
	if ( WSAStartup(MAKEWORD(1,1), &wsadata) ) 
		return -1;

	if ( 0 > (sock = socket (AF_INET, SOCK_DGRAM, 0)) ) 
		{
		perror( "socket");
		return  -1;
		}
	
	memset(&addr, 0, sizeof(struct sockaddr_in)); 
	addr.sin_family = AF_INET; 
	addr.sin_addr.s_addr = htons(INADDR_ANY); 
	addr.sin_port = htons(port); 

        if ( bind(sock, (struct sockaddr *)&addr, sizeof(struct sockaddr_in)) < 0 )
                { 
		perror("bind"); 
		WSACleanup(); 
		return        -1; 
	       } 

	printf("Start listening - press Control+C to abort\n");

        while ( 0 <= (rc = recv(sock , buf, sizeof(buf), 0)) )
                {
                if ( rc > 0 )
                        printf("Got: %.*s\n",ntohs(ptr->len),ptr->url);
		else	continue;

		ptr->len = ntohs(ptr->len);
		ptr->url[ptr->len] = '\0';
		
		/*
		** Compute etalon hash and compare
		*/
	        MD5Init(&md5);
        	MD5Update(&md5,&ptr->url,ptr->len);
	        MD5Update(&md5,secret,secretlen);
        	MD5Final(&hash,&md5);
        	
        	if ( memcmp(&hash,&ptr->hash,16) )
        	       {
        	       printf("Hash error!!!");
        	       continue;
        	       }

	
		/*
		** Start Internet Browser with the URL as argument
		*/
		ShellExecute ( NULL, "open", ptr->url,
		               NULL, NULL, SW_SHOWNORMAL );
                }
        
        printf("rc = %d\n",rc);
                        
        if ( rc < 0 )
		{
		WSAGetLastError();
		perror( "recv");
		return  -1;
		}
	
	
	
        /*
        ** Cleanup & exit
        */        
        WSACleanup();
         
	return 0;
}