/* Prototype uptime daemon for uptime.eggheads.org/uptime.energymech.net
 * (c) 2001 MadCamel and proton - Public Domain
 * 
 * This just recieves the packets and prints them. The system in use today
 * pokes the values into a mySQL table.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <signal.h>
#include <ctype.h>

#define PERR(x)        { perror(x); exit(1); }
#define LPORT 9969

char filterchars[256] =
{
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	1,  1,  1,  1,  1,  1,  1,  0,
	1,  1,  1,  1,  1,  1,  1,  1, 
	1,  1,  1,  1,  1,  1,  1,  1, 
	1,  1,  1,  1,  1,  1,  1,  1,
	1,  1,  1,  1,  1,  1,  1,  1,
	1,  1,  1,  1,  1,  1,  1,  1,
	1,  1,  1,  1,  1,  1,  1,  1,
	1,  1,  1,  1,  1,  1,  1,  1,
	1,  1,  1,  1,  1,  1,  1,  1,
	1,  1,  1,  1,  1,  1,  1,  1,
	1,  1,  1,  1,  1,  1,  1,  1,
	1,  1,  1,  1,  1,  1,  1,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0,
	0,  0,  0,  0,  0,  0,  0,  0
};

char	executable[40];
int	sock;

typedef struct upPack
{
	int	regnr;
	int	pid;
	int	type;
	ulong	cookie;
	ulong	uptime;
	ulong	ontime;
	ulong	now;
	ulong	sysup;
	char	string[1];
}
upPack;

int bindsock (int port)
{
	struct sockaddr_in sai;
	int s;

	if ((s = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
		PERR ("Socket");

	sai.sin_family = AF_INET;
	sai.sin_port = htons (port);
	sai.sin_addr.s_addr = INADDR_ANY;

	if (bind (s, (struct sockaddr *) &sai, sizeof (sai)) < 0)
		PERR ("Bind");

	return s;
}

void handle_segv (const int sig)
{
	close (sock);
	execl (executable, executable, NULL);
	_exit (0);
}

#define PACKSIZE	512

int main (int argc, char **argv)
{
	struct	sockaddr_in sai;
	struct	upPack *up;
	char	packet[PACKSIZE];
	char	*pt;
	int	sz,res;

	strcpy(executable,*argv);
	signal(SIGSEGV,handle_segv);

	up = (struct upPack *)packet;

	sock = bindsock(LPORT);

loopit:
	sz = sizeof(sai);
	res = recvfrom(sock,&packet,PACKSIZE-1,0,(struct sockaddr *)&sai,&sz);
	/*
	 *  Why +5 ?
	 *
	 *  Minimum nick length      1
	 *  Space                    1
	 *  Minimum hostname         1 (`x' is a legal hostname)
	 *  Space                    1
	 *  Minimal version string   1 (they may hack versions all they want)
	 *  \0                       1
	 *  upPack.string[1]        -1 (+1 is added extra by sizeof(upPack))
	 *  ---------------------------
	 *  Total                   +5
	 */
	if (res < (sizeof(upPack)+5))
		goto loopit;

	/*
	 *  res can not be bigger than res - 1 == 511 == end of buffer
	 *  This already IS a \0 unless the client has been hacked <g>
	 */
	packet[res] = 0;

	printf("%s ",inet_ntoa(sai.sin_addr));
	printf("%i ",ntohs(sai.sin_port));
	printf("%i ",up->regnr);
	printf("%i ",up->pid);
	printf("%i ",up->type);
	printf("%lu ",up->cookie);
	printf("%lu ",up->uptime);
	printf("%lu ",up->ontime);
	printf("%lu ",up->now);
	printf("%lu ",up->sysup);

	/*
	 *  evil char filter, drop anything that looks ugly
	 */
	for(pt=up->string;*pt;pt++)
	{
		if (filterchars[(unsigned char)*pt] == 0)
			goto loopit;
	}

	printf("%s\n",up->string);

	goto loopit;
}