/*
 * iptables module to match IP address ranges
 *   (c) 2003 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu <mailto:kadlec@blackhole.kfki.hu>>
 *
 * Released under the terms of GNU GPLv2.
 *
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_iprange.h>

MODULE_LICENSE("GPL");

#if 0
#define DEBUGP printk
#else
#define DEBUGP(format, args...)
#endif

static int
match(const struct sk_buff *skb,
      const struct net_device *in,
      const struct net_device *out,
      const void *matchinfo,
      int offset,
      const void *hdr,
      u_int16_t datalen,
      int *hotdrop)
{
       const struct ipt_iprange_info *info = matchinfo;
       const struct iphdr *iph = skb->nh.iph;
       

       if (info->flags & IPRANGE_SRC) {
               if (((ntohl(iph->saddr) < ntohl(info->src.min_ip))
                         || (ntohl(iph->saddr) > ntohl(info->src.max_ip)))
                        ^ !!(info->flags & IPRANGE_SRC_INV)) {
                       DEBUGP("src IP %u.%u.%u.%u NOT in range %s"
                              "%u.%u.%u.%u-%u.%u.%u.%u\n",
                               NIPQUAD(iph->saddr),
                               info->flags & IPRANGE_SRC_INV ? "(INV) " : "",
                               NIPQUAD(info->src.min_ip),
                               NIPQUAD(info->src.max_ip));
                       return 0;
               }
       }
       if (info->flags & IPRANGE_DST) {
               if (((ntohl(iph->daddr) < ntohl(info->dst.min_ip))
                         || (ntohl(iph->daddr) > ntohl(info->dst.max_ip)))
                        ^ !!(info->flags & IPRANGE_DST_INV)) {
                       DEBUGP("dst IP %u.%u.%u.%u NOT in range %s"
                              "%u.%u.%u.%u-%u.%u.%u.%u\n",
                               NIPQUAD(iph->daddr),
                               info->flags & IPRANGE_DST_INV ? "(INV) " : "",
                               NIPQUAD(info->dst.min_ip),
                               NIPQUAD(info->dst.max_ip));
                       return 0;
               }
       }
       return 1;
}

static int check(const char *tablename,
                const struct ipt_ip *ip,
                void *matchinfo,
                unsigned int matchsize,
                unsigned int hook_mask)
{
       /* verify size */
       if (matchsize != IPT_ALIGN(sizeof(struct ipt_iprange_info)))
               return 0;

       return 1;
}

static struct ipt_match iprange_match = 
{ 
       .list = { NULL, NULL }, 
       .name = "iprange", 
       .match = &match, 
       .checkentry = &check, 
       .destroy = NULL, 
       .me = THIS_MODULE
};

static int __init init(void)
{
       return ipt_register_match(&iprange_match);
}

static void __exit fini(void)
{
       ipt_unregister_match(&iprange_match);
}

module_init(init);
module_exit(fini);