LXR linux/net/netfilter/xt

   1/*
   2 *      xt_iprange - Netfilter module to match IP address ranges
   3 *
   4 *      (C) 2003 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
   5 *      (C) CC Computer Consultants GmbH, 2008
   6 *
   7 *      This program is free software; you can redistribute it and/or modify
   8 *      it under the terms of the GNU General Public License version 2 as
   9 *      published by the Free Software Foundation.
  10 */
  11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12#include <linux/module.h>
  13#include <linux/skbuff.h>
  14#include <linux/ip.h>
  15#include <linux/ipv6.h>
  16#include <linux/netfilter/x_tables.h>
  17#include <linux/netfilter/xt_iprange.h>
  18
  19static bool
  20iprange_mt4(const struct sk_buff *skb, struct xt_action_param *par)
  21{
  22        const struct xt_iprange_mtinfo *info = par->matchinfo;
  23        const struct iphdr *iph = ip_hdr(skb);
  24        bool m;
  25
  26        if (info->flags & IPRANGE_SRC) {
  27                m  = ntohl(iph->saddr) < ntohl(info->src_min.ip);
  28                m |= ntohl(iph->saddr) > ntohl(info->src_max.ip);
  29                m ^= !!(info->flags & IPRANGE_SRC_INV);
  30                if (m) {
  31                        pr_debug("src IP %pI4 NOT in range %s%pI4-%pI4\n",
  32                                 &iph->saddr,
  33                                 (info->flags & IPRANGE_SRC_INV) ? "(INV) " : "",
  34                                 &info->src_max.ip,
  35                                 &info->src_max.ip);
  36                        return false;
  37                }
  38        }
  39        if (info->flags & IPRANGE_DST) {
  40                m  = ntohl(iph->daddr) < ntohl(info->dst_min.ip);
  41                m |= ntohl(iph->daddr) > ntohl(info->dst_max.ip);
  42                m ^= !!(info->flags & IPRANGE_DST_INV);
  43                if (m) {
  44                        pr_debug("dst IP %pI4 NOT in range %s%pI4-%pI4\n",
  45                                 &iph->daddr,
  46                                 (info->flags & IPRANGE_DST_INV) ? "(INV) " : "",
  47                                 &info->dst_min.ip,
  48                                 &info->dst_max.ip);
  49                        return false;
  50                }
  51        }
  52        return true;
  53}
  54
  55static inline int
  56iprange_ipv6_lt(const struct in6_addr *a, const struct in6_addr *b)
  57{
  58        unsigned int i;
  59
  60        for (i = 0; i < 4; ++i) {
  61                if (a->s6_addr32[i] != b->s6_addr32[i])
  62                        return ntohl(a->s6_addr32[i]) < ntohl(b->s6_addr32[i]);
  63        }
  64
  65        return 0;
  66}
  67
  68static bool
  69iprange_mt6(const struct sk_buff *skb, struct xt_action_param *par)
  70{
  71        const struct xt_iprange_mtinfo *info = par->matchinfo;
  72        const struct ipv6hdr *iph = ipv6_hdr(skb);
  73        bool m;
  74
  75        if (info->flags & IPRANGE_SRC) {
  76                m  = iprange_ipv6_lt(&iph->saddr, &info->src_min.in6);
  77                m |= iprange_ipv6_lt(&info->src_max.in6, &iph->saddr);
  78                m ^= !!(info->flags & IPRANGE_SRC_INV);
  79                if (m)
  80                        return false;
  81        }
  82        if (info->flags & IPRANGE_DST) {
  83                m  = iprange_ipv6_lt(&iph->daddr, &info->dst_min.in6);
  84                m |= iprange_ipv6_lt(&info->dst_max.in6, &iph->daddr);
  85                m ^= !!(info->flags & IPRANGE_DST_INV);
  86                if (m)
  87                        return false;
  88        }
  89        return true;
  90}
  91
  92static struct xt_match iprange_mt_reg[] __read_mostly = {
  93        {
  94                .name      = "iprange",
  95                .revision  = 1,
  96                .family    = NFPROTO_IPV4,
  97                .match     = iprange_mt4,
  98                .matchsize = sizeof(struct xt_iprange_mtinfo),
  99                .me        = THIS_MODULE,
 100        },
 101        {
 102                .name      = "iprange",
 103                .revision  = 1,
 104                .family    = NFPROTO_IPV6,
 105                .match     = iprange_mt6,
 106                .matchsize = sizeof(struct xt_iprange_mtinfo),
 107                .me        = THIS_MODULE,
 108        },
 109};
 110
 111static int __init iprange_mt_init(void)
 112{
 113        return xt_register_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 114}
 115
 116static void __exit iprange_mt_exit(void)
 117{
 118        xt_unregister_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 119}
 120
 121module_init(iprange_mt_init);
 122module_exit(iprange_mt_exit);
 123MODULE_LICENSE("GPL");
 124MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>");
 125MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
 126MODULE_DESCRIPTION("Xtables: arbitrary IPv4 range matching");
 127MODULE_ALIAS("ipt_iprange");
 128MODULE_ALIAS("ip6t_iprange");
 129