//Dynu Premium Dynamic DNS Client v2.1
//Copyright (c) 1997-2001 Dynu Systems, Inc.
//All rights reserved.
//Compile line: g++ premium.c -o dynupremium

//Source modified to compile under FreeBSD.
//Paul A. Hoadley <paulh@logicsquad.net>

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <syslog.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <iostream.h>

#ifndef SIOCGIFADDR
#include <linux/sockios.h>
#endif

#define DEBUG

#define IPLEN			16
#define CONFSTRLEN		64

int	debug			= 	0;
int	log2syslog		= 	0;
char	suppliedIP[IPLEN+6];
char	device[CONFSTRLEN];
char	ipaddress[IPLEN]	=	"";
char	lastipaddress[IPLEN];
char    ipdetect[1];  		//1-Server side  //2-Client side  //3-Both //4-Specify
int	NAT			=	0;
int	PROXY			=	0;
int	DAEMON			=	0;
int	POLLINTERVAL		=	30;

struct ac
{
 char first[50], second[70], password[8];
 ac *next;
};


//Function Definitions BEGIN///////////////////////////////////////////////
int 	fetchURL(char first[50], char second[70], char password[8], char ipaddress[IPLEN]);
void	GetIP(char *p);
void	ErrMsg(char *fmt, ...);
//Function Definitions END/////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////
//MAIN PROGRAM BEGIN///////////////////////////////////////////////////////
main()
{
	ac *cell, *first, *move;
	char more[2];
	char temp[255];	
        char onechar[2];
	char responses[2048];

	onechar[0] = 'n';
	onechar[1] = '\0';
	ipdetect[0] = '1';
	ipdetect[1] = '\0';
	more[0] = 'y';	
	more[1] = '\0';
	responses[0] = '\0';
	first = NULL;
	cell = NULL;
	move = NULL;
	cout << "Dynu Premium Client v2.0" << endl;
	
	//Check if firewall exists.
	cout << "Are you behind a firewall(NAT)?(y/n) : ";
	cin >> onechar[0];
	strcat(responses, onechar);
	strcat(responses, "\r\n");
	if (onechar[0] == 'y' || onechar[0] == 'Y')
		NAT = 1;
		
	//Get IPDETECT type		
	cout << "Please choose one of the following IP detection options:" << endl;
	cout << "1 - Detect IP from Dynu server side";
	if (NAT)
		cout << "(Recommended behind NAT firewall)";
	cout << endl << "2 - Detect IP on my computer" << endl;
	cout << "3 - I want to specify my IP address" << endl;
	cout << "(1-3) : ";
	cin >> ipdetect[0];
	strcat(responses, ipdetect);
	strcat(responses, "\r\n");
	if (ipdetect[0] == '3')
	{
	 	cout << "What is your IP Address? : ";
	 	cin >> ipaddress;
	 	strcat(responses, ipaddress);
 		strcat(responses, "\r\n");
	}
	
	if (ipdetect[0] == '2')
	{	
		//Get the device name
		cout << "Please enter the device used to make external connection(The value for this can be obtained by looking at the output of the /sbin/ifconfig program while connected to the Net. e.g. eth0 or ppp0) : ";
		cin >> device;
		strcat(responses, device);
		strcat(responses, "\r\n");
	}
	
	//Check to run once or perpetually
	cout << "Would you like Dynu Premium Client to keep running in the background?(y/n) : ";
	cin >> onechar[0];
	strcat(responses, onechar);
	strcat(responses, "\r\n");
	if (onechar[0] == 'y' || onechar[0] == 'Y')
		DAEMON = 1;
		
	//Get user defined poll interval
	cout << "How often in seconds should the client poll to check for IP Address changes : ";
	cin >> POLLINTERVAL;
	sprintf(responses, "%s%d", responses, POLLINTERVAL);
	strcat(responses, "\r\n");
		
	//Load the domains and password	
	while(more[0] == 'y' || more[0] == 'Y')
	{
		if (cell == NULL)
			cell = new ac;
		else
		{
			cell->next = new ac;
			cell = cell->next;	
		}
		if (first == NULL) 
			first = cell;
		cout << "Please type your domain(e.g. dynu, microsoft, netscape etc): ";
		cin >> cell->second;
		strcat(responses, cell->second);
		strcat(responses, "\r\n");
		cout << "Please type your top level(e.g. com, net, co.uk etc): ";
		cin >> cell->first;
		strcat(responses, cell->first);
		strcat(responses, "\r\n");
		cout << "Please type your password(6-8 characters): ";
		cin >> cell->password;
		strcat(responses, cell->password);
		strcat(responses, "\r\n");
		cout << "Do you want add another domain?(y/n): ";		
		cin >> more[0];
		strcat(responses, more);
		strcat(responses, "\r\n");
	}
	cout << "Would you like to save these settings so you can run Dynu Premium using the command './dynupremium < premium.cfg'?(y/n) : ";
	cin >> onechar[0];
	strcat(responses, onechar);
	strcat(responses, "\r\n\0");
	if (onechar[0] == 'y' || onechar[0] == 'Y')
	{
		//save the settings to premium.cfg file
		FILE	*fildes;
		fildes = fopen("premium.cfg","w");		
		fprintf(fildes, responses);
		fclose(fildes);
	}

	if (DAEMON)	//Run continuosly in the background
	{	
		int x;
		x = fork();
		switch (x)
		{
		 	case -1:	//error
		 	default:        //parent
		 		exit(0);
		 	case 0:         //child
		 		setsid();
				syslog(LOG_INFO, "Dynu Premium Client started as a background process\n");		 		
				cout << "Dynu Premium Client running...\r\n";	
				cell = first;
				while(1)
				{
				while(cell != NULL)
				{      	
					strcpy(lastipaddress,ipaddress);
					if (ipdetect[0] == '2')
					{
					        GetIP(ipaddress);			
					}
					fetchURL(cell->first, cell->second, cell->password, ipaddress);
					cell = cell->next;
				}
				sleep(POLLINTERVAL);
				}
				break;
		}
	}
	else		//Run only once and quit
	{
		cell = first;
		while(cell != NULL)
		{
			strcpy(lastipaddress,ipaddress);
			if (ipdetect[0] == '2')
			{
		        GetIP(ipaddress);			
			}
			fetchURL(cell->first, cell->second, cell->password, ipaddress);
			cell = cell->next;
		}
	}
	return(0);
}
//MAIN PROGRAM END/////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////
//Function fetchURL BEGIN//////////////////////////////////////////////////
int fetchURL(char first[50], char second[70], char password[8], char ipaddress[IPLEN])
{
	int sock1;
	struct sockaddr_in server ;
   	struct hostent *hp;
   	const char *servername = "premiumupdate.dynu.com";
	char reply[512], ch[2], url[255];
	bool flag=false;
	bool error=false;

	strcpy(url, "GET http://premiumupdate.dynu.com:80/premium/update.asp?first=");
	strcat(url, first);
	strcat(url, "&second=");
	strcat(url, second);
	strcat(url, "&password=");
	strcat(url, password);
	strcat(url, "&ip_address=");
	strcat(url, ipaddress);
	strcat(url, " HTTP/1.0\n\n");

	sock1 = socket(AF_INET, SOCK_STREAM,0);
	if ( sock1 < 0 )
	{
	 	//perror("Error creating socket!\n");
	 	return 0;
	}
	else
	{

	   server.sin_family = AF_INET;
	   hp = gethostbyname(servername);
	   bcopy(hp->h_addr, &(server.sin_addr.s_addr), hp->h_length);
	   server.sin_port = htons(80);
	   if ( connect(sock1,(struct sockaddr *)&server, sizeof(server)) < 0 )
	   {
       	   	close(sock1);
	   	//perror("Error in connecting a stream socket");
	   	return 0;
   	   }
	   else
	   {
		if ( write(sock1, url, strlen(url)) <0)
		{
			//cout << "Error writing to server\n";
			return 0;
		}
		else
		{
			if ( read(sock1, reply,512) < 0 )
			{
				//error reading from socket	
				return 0;
			}
			else
			{
				if (strstr(reply,"expired")!=NULL)
					cout << "Dynu Premium subscription for " << second << "." << first << " has expired! Please visit http://www.dynu.com to extend your subscription.\r\n";
				if (strstr(reply,"nodomain")!=NULL)
					cout << "Domain " << second << "." << first << " does not exist! Please check the domain to make sure it is registered!\r\n";
				if (strstr(reply,"wrongpassword")!=NULL)
					cout << "The password for domain " << second << "." << first << " is incorrect! Please start up Dynu Premium Client with the right password again!\r\n";				
				close(sock1);	
			}			
		}
 	   }				
	}
	return 1;
}
//Function fetchURL END////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////
//Function GetIP BEGIN/////////////////////////////////////////////////////
void GetIP(char *p)
{
	int	fd;
	int	*x;
	struct	ifreq ifr;
	struct	in_addr z;

	*p = 0;		// remove old address
	/* Create a channel to the NET kernel. */
	if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
	    ErrMsg("Can't talk to kernel! (%d)\n", errno);
	    return;
	}
	strcpy(ifr.ifr_name, device);
	if (ioctl(fd, SIOCGIFFLAGS, &ifr) < 0)  {
	    ErrMsg("Can't get status for %s. (%d)\n", device, errno);
	    close(fd);
	    return;
	}
	if ((ifr.ifr_flags & IFF_UP) == 0)  {
// No longer print message when interface down  (johna 6-28-00)
//	    ErrMsg("Interface %s not active.\n", device);
	    close(fd);
	    return;
	}
	if (ioctl(fd, SIOCGIFADDR, &ifr) != 0) {
	    ErrMsg("Can't get IP address for %s. (%d)\n", device, errno);
	    close(fd);
	    return;
	}
	close(fd);
	x = (int *)&ifr.ifr_addr;	// seems to be off by 2 bytes
	z.s_addr = x[1];
	strcpy(p, inet_ntoa(z));
	//sprintf(suppliedIP, "&ip=%s", p);  // force sending local address
}
//Function GetIP END///////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////
//Function ErrMsg BEGIN////////////////////////////////////////////////////
void ErrMsg(char *fmt, ...)
{
	va_list ap;
	char	errmsg[256];

	va_start(ap, fmt);
	vsprintf(errmsg, fmt, ap);
	va_end(ap);
	if (log2syslog)
		syslog(LOG_ERR, "%s\n", errmsg);
	else
		fprintf(stderr, "%s\n", errmsg);
}
//Function ErrMsg END//////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////