net/netfilter/xt_iprange.c

   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 #include <linux/module.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/ip.h>
  14 #include <linux/ipv6.h>
  15 #include <linux/netfilter/x_tables.h>
  16 #include <linux/netfilter/xt_iprange.h>
  17
  18 static bool
  19 iprange_mt4(const struct sk_buff *skb, const struct xt_match_param *par)
  20 {
  21         const struct xt_iprange_mtinfo *info = par->matchinfo;
  22         const struct iphdr *iph = ip_hdr(skb);
  23         bool m;
  24
  25         if (info->flags & IPRANGE_SRC) {
  26                 m  = ntohl(iph->saddr) < ntohl(info->src_min.ip);
  27                 m |= ntohl(iph->saddr) > ntohl(info->src_max.ip);
  28                 m ^= !!(info->flags & IPRANGE_SRC_INV);
  29                 if (m) {
  30                         pr_debug("src IP %pI4 NOT in range %s%pI4-%pI4\n",
  31                                  &iph->saddr,
  32                                  (info->flags & IPRANGE_SRC_INV) ? "(INV) " : "",
  33                                  &info->src_max.ip,
  34                                  &info->src_max.ip);
  35                         return false;
  36                 }
  37         }
  38         if (info->flags & IPRANGE_DST) {
  39                 m  = ntohl(iph->daddr) < ntohl(info->dst_min.ip);
  40                 m |= ntohl(iph->daddr) > ntohl(info->dst_max.ip);
  41                 m ^= !!(info->flags & IPRANGE_DST_INV);
  42                 if (m) {
  43                         pr_debug("dst IP %pI4 NOT in range %s%pI4-%pI4\n",
  44                                  &iph->daddr,
  45                                  (info->flags & IPRANGE_DST_INV) ? "(INV) " : "",
  46                                  &info->dst_min.ip,
  47                                  &info->dst_max.ip);
  48                         return false;
  49                 }
  50         }
  51         return true;
  52 }
  53
  54 static inline int
  55 iprange_ipv6_sub(const struct in6_addr *a, const struct in6_addr *b)
  56 {
  57         unsigned int i;
  58         int r;
  59
  60         for (i = 0; i < 4; ++i) {
  61                 r = ntohl(a->s6_addr32[i]) - ntohl(b->s6_addr32[i]);
  62                 if (r != 0)
  63                         return r;
  64         }
  65
  66         return 0;
  67 }
  68
  69 static bool
  70 iprange_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
  71 {
  72         const struct xt_iprange_mtinfo *info = par->matchinfo;
  73         const struct ipv6hdr *iph = ipv6_hdr(skb);
  74         bool m;
  75
  76         if (info->flags & IPRANGE_SRC) {
  77                 m  = iprange_ipv6_sub(&iph->saddr, &info->src_min.in6) < 0;
  78                 m |= iprange_ipv6_sub(&iph->saddr, &info->src_max.in6) > 0;
  79                 m ^= !!(info->flags & IPRANGE_SRC_INV);
  80                 if (m)
  81                         return false;
  82         }
  83         if (info->flags & IPRANGE_DST) {
  84                 m  = iprange_ipv6_sub(&iph->daddr, &info->dst_min.in6) < 0;
  85                 m |= iprange_ipv6_sub(&iph->daddr, &info->dst_max.in6) > 0;
  86                 m ^= !!(info->flags & IPRANGE_DST_INV);
  87                 if (m)
  88                         return false;
  89         }
  90         return true;
  91 }
  92
  93 static struct xt_match iprange_mt_reg[] __read_mostly = {
  94         {
  95                 .name      = "iprange",
  96                 .revision  = 1,
  97                 .family    = NFPROTO_IPV4,
  98                 .match     = iprange_mt4,
  99                 .matchsize = sizeof(struct xt_iprange_mtinfo),
 100                 .me        = THIS_MODULE,
 101         },
 102         {
 103                 .name      = "iprange",
 104                 .revision  = 1,
 105                 .family    = NFPROTO_IPV6,
 106                 .match     = iprange_mt6,
 107                 .matchsize = sizeof(struct xt_iprange_mtinfo),
 108                 .me        = THIS_MODULE,
 109         },
 110 };
 111
 112 static int __init iprange_mt_init(void)
 113 {
 114         return xt_register_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 115 }
 116
 117 static void __exit iprange_mt_exit(void)
 118 {
 119         xt_unregister_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 120 }
 121
 122 module_init(iprange_mt_init);
 123 module_exit(iprange_mt_exit);
 124 MODULE_LICENSE("GPL");
 125 MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>");
 126 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
 127 MODULE_DESCRIPTION("Xtables: arbitrary IPv4 range matching");
 128 MODULE_ALIAS("ipt_iprange");
 129 MODULE_ALIAS("ip6t_iprange");