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 #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
  19 static bool
  20 iprange_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
  55 static inline int
  56 iprange_ipv6_sub(const struct in6_addr *a, const struct in6_addr *b)
  57 {
  58         unsigned int i;
  59         int r;
  60
  61         for (i = 0; i < 4; ++i) {
  62                 r = ntohl(a->s6_addr32[i]) - ntohl(b->s6_addr32[i]);
  63                 if (r != 0)
  64                         return r;
  65         }
  66
  67         return 0;
  68 }
  69
  70 static bool
  71 iprange_mt6(const struct sk_buff *skb, struct xt_action_param *par)
  72 {
  73         const struct xt_iprange_mtinfo *info = par->matchinfo;
  74         const struct ipv6hdr *iph = ipv6_hdr(skb);
  75         bool m;
  76
  77         if (info->flags & IPRANGE_SRC) {
  78                 m  = iprange_ipv6_sub(&iph->saddr, &info->src_min.in6) < 0;
  79                 m |= iprange_ipv6_sub(&iph->saddr, &info->src_max.in6) > 0;
  80                 m ^= !!(info->flags & IPRANGE_SRC_INV);
  81                 if (m)
  82                         return false;
  83         }
  84         if (info->flags & IPRANGE_DST) {
  85                 m  = iprange_ipv6_sub(&iph->daddr, &info->dst_min.in6) < 0;
  86                 m |= iprange_ipv6_sub(&iph->daddr, &info->dst_max.in6) > 0;
  87                 m ^= !!(info->flags & IPRANGE_DST_INV);
  88                 if (m)
  89                         return false;
  90         }
  91         return true;
  92 }
  93
  94 static struct xt_match iprange_mt_reg[] __read_mostly = {
  95         {
  96                 .name      = "iprange",
  97                 .revision  = 1,
  98                 .family    = NFPROTO_IPV4,
  99                 .match     = iprange_mt4,
 100                 .matchsize = sizeof(struct xt_iprange_mtinfo),
 101                 .me        = THIS_MODULE,
 102         },
 103         {
 104                 .name      = "iprange",
 105                 .revision  = 1,
 106                 .family    = NFPROTO_IPV6,
 107                 .match     = iprange_mt6,
 108                 .matchsize = sizeof(struct xt_iprange_mtinfo),
 109                 .me        = THIS_MODULE,
 110         },
 111 };
 112
 113 static int __init iprange_mt_init(void)
 114 {
 115         return xt_register_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 116 }
 117
 118 static void __exit iprange_mt_exit(void)
 119 {
 120         xt_unregister_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 121 }
 122
 123 module_init(iprange_mt_init);
 124 module_exit(iprange_mt_exit);
 125 MODULE_LICENSE("GPL");
 126 MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>");
 127 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
 128 MODULE_DESCRIPTION("Xtables: arbitrary IPv4 range matching");
 129 MODULE_ALIAS("ipt_iprange");
 130 MODULE_ALIAS("ip6t_iprange");