/*

   *	xt_iprange - Netfilter module to match IP address ranges

   *

   *	(C) 2003 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>

   *	(C) CC Computer Consultants GmbH, 2008

   *

   *	This program is free software; you can redistribute it and/or modify
   *	it under the terms of the GNU General Public License version 2 as
   *	published by the Free Software Foundation.

   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/module.h>
  #include <linux/skbuff.h>
  #include <linux/ip.h>

  #include <linux/ipv6.h>

  #include <linux/netfilter/x_tables.h>

  #include <linux/netfilter/xt_iprange.h>

  static bool

  iprange_mt4(const struct sk_buff *skb, struct xt_action_param *par)

  {

  	const struct xt_iprange_mtinfo *info = par->matchinfo;

  	const struct iphdr *iph = ip_hdr(skb);
  	bool m;
  
  	if (info->flags & IPRANGE_SRC) {
  		m  = ntohl(iph->saddr) < ntohl(info->src_min.ip);
  		m |= ntohl(iph->saddr) > ntohl(info->src_max.ip);

  		m ^= !!(info->flags & IPRANGE_SRC_INV);

  		if (m) {

  			pr_debug("src IP %pI4 NOT in range %s%pI4-%pI4
  ",
  			         &iph->saddr,

  			         (info->flags & IPRANGE_SRC_INV) ? "(INV) " : "",

  			         &info->src_min.ip,

  			         &info->src_max.ip);

  			return false;
  		}
  	}
  	if (info->flags & IPRANGE_DST) {
  		m  = ntohl(iph->daddr) < ntohl(info->dst_min.ip);
  		m |= ntohl(iph->daddr) > ntohl(info->dst_max.ip);

  		m ^= !!(info->flags & IPRANGE_DST_INV);

  		if (m) {

  			pr_debug("dst IP %pI4 NOT in range %s%pI4-%pI4
  ",
  			         &iph->daddr,

  			         (info->flags & IPRANGE_DST_INV) ? "(INV) " : "",

  			         &info->dst_min.ip,
  			         &info->dst_max.ip);

  			return false;
  		}
  	}
  	return true;
  }
  
  static inline int

  iprange_ipv6_lt(const struct in6_addr *a, const struct in6_addr *b)

  {
  	unsigned int i;

  
  	for (i = 0; i < 4; ++i) {

  		if (a->s6_addr32[i] != b->s6_addr32[i])
  			return ntohl(a->s6_addr32[i]) < ntohl(b->s6_addr32[i]);

  	}
  
  	return 0;
  }
  
  static bool

  iprange_mt6(const struct sk_buff *skb, struct xt_action_param *par)

  {

  	const struct xt_iprange_mtinfo *info = par->matchinfo;

  	const struct ipv6hdr *iph = ipv6_hdr(skb);
  	bool m;
  
  	if (info->flags & IPRANGE_SRC) {

  		m  = iprange_ipv6_lt(&iph->saddr, &info->src_min.in6);
  		m |= iprange_ipv6_lt(&info->src_max.in6, &iph->saddr);

  		m ^= !!(info->flags & IPRANGE_SRC_INV);

  		if (m) {
  			pr_debug("src IP %pI6 NOT in range %s%pI6-%pI6
  ",
  				 &iph->saddr,
  				 (info->flags & IPRANGE_SRC_INV) ? "(INV) " : "",
  				 &info->src_min.in6,
  				 &info->src_max.in6);

  			return false;

  		}

  	}
  	if (info->flags & IPRANGE_DST) {

  		m  = iprange_ipv6_lt(&iph->daddr, &info->dst_min.in6);
  		m |= iprange_ipv6_lt(&info->dst_max.in6, &iph->daddr);

  		m ^= !!(info->flags & IPRANGE_DST_INV);

  		if (m) {
  			pr_debug("dst IP %pI6 NOT in range %s%pI6-%pI6
  ",
  				 &iph->daddr,
  				 (info->flags & IPRANGE_DST_INV) ? "(INV) " : "",
  				 &info->dst_min.in6,
  				 &info->dst_max.in6);

  			return false;

  		}

  	}
  	return true;
  }
  
  static struct xt_match iprange_mt_reg[] __read_mostly = {
  	{
  		.name      = "iprange",

  		.revision  = 1,

  		.family    = NFPROTO_IPV4,

  		.match     = iprange_mt4,
  		.matchsize = sizeof(struct xt_iprange_mtinfo),
  		.me        = THIS_MODULE,
  	},
  	{
  		.name      = "iprange",
  		.revision  = 1,

  		.family    = NFPROTO_IPV6,

  		.match     = iprange_mt6,
  		.matchsize = sizeof(struct xt_iprange_mtinfo),
  		.me        = THIS_MODULE,
  	},

  };

  static int __init iprange_mt_init(void)

  {

  	return xt_register_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));

  }

  static void __exit iprange_mt_exit(void)

  {

  	xt_unregister_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));

  }

  module_init(iprange_mt_init);
  module_exit(iprange_mt_exit);

  MODULE_LICENSE("GPL");

  MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>");
  MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");

  MODULE_DESCRIPTION("Xtables: arbitrary IPv4 range matching");

  MODULE_ALIAS("ipt_iprange");
  MODULE_ALIAS("ip6t_iprange");