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 #include <linux/netfilter_ipv4/ipt_iprange.h>
  18
  19 static bool
  20 iprange_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par)
  21 {
  22         const struct ipt_iprange_info *info = par->matchinfo;
  23         const struct iphdr *iph = ip_hdr(skb);
  24
  25         if (info->flags & IPRANGE_SRC) {
  26                 if ((ntohl(iph->saddr) < ntohl(info->src.min_ip)
  27                           || ntohl(iph->saddr) > ntohl(info->src.max_ip))
  28                          ^ !!(info->flags & IPRANGE_SRC_INV)) {
  29                         pr_debug("src IP %u.%u.%u.%u NOT in range %s"
  30                                  "%u.%u.%u.%u-%u.%u.%u.%u\n",
  31                                  NIPQUAD(iph->saddr),
  32                                  info->flags & IPRANGE_SRC_INV ? "(INV) " : "",
  33                                  NIPQUAD(info->src.min_ip),
  34                                  NIPQUAD(info->src.max_ip));
  35                         return false;
  36                 }
  37         }
  38         if (info->flags & IPRANGE_DST) {
  39                 if ((ntohl(iph->daddr) < ntohl(info->dst.min_ip)
  40                           || ntohl(iph->daddr) > ntohl(info->dst.max_ip))
  41                          ^ !!(info->flags & IPRANGE_DST_INV)) {
  42                         pr_debug("dst IP %u.%u.%u.%u NOT in range %s"
  43                                  "%u.%u.%u.%u-%u.%u.%u.%u\n",
  44                                  NIPQUAD(iph->daddr),
  45                                  info->flags & IPRANGE_DST_INV ? "(INV) " : "",
  46                                  NIPQUAD(info->dst.min_ip),
  47                                  NIPQUAD(info->dst.max_ip));
  48                         return false;
  49                 }
  50         }
  51         return true;
  52 }
  53
  54 static bool
  55 iprange_mt4(const struct sk_buff *skb, const struct xt_match_param *par)
  56 {
  57         const struct xt_iprange_mtinfo *info = par->matchinfo;
  58         const struct iphdr *iph = ip_hdr(skb);
  59         bool m;
  60
  61         if (info->flags & IPRANGE_SRC) {
  62                 m  = ntohl(iph->saddr) < ntohl(info->src_min.ip);
  63                 m |= ntohl(iph->saddr) > ntohl(info->src_max.ip);
  64                 m ^= info->flags & IPRANGE_SRC_INV;
  65                 if (m) {
  66                         pr_debug("src IP " NIPQUAD_FMT " NOT in range %s"
  67                                  NIPQUAD_FMT "-" NIPQUAD_FMT "\n",
  68                                  NIPQUAD(iph->saddr),
  69                                  (info->flags & IPRANGE_SRC_INV) ? "(INV) " : "",
  70                                  NIPQUAD(info->src_max.ip),
  71                                  NIPQUAD(info->src_max.ip));
  72                         return false;
  73                 }
  74         }
  75         if (info->flags & IPRANGE_DST) {
  76                 m  = ntohl(iph->daddr) < ntohl(info->dst_min.ip);
  77                 m |= ntohl(iph->daddr) > ntohl(info->dst_max.ip);
  78                 m ^= info->flags & IPRANGE_DST_INV;
  79                 if (m) {
  80                         pr_debug("dst IP " NIPQUAD_FMT " NOT in range %s"
  81                                  NIPQUAD_FMT "-" NIPQUAD_FMT "\n",
  82                                  NIPQUAD(iph->daddr),
  83                                  (info->flags & IPRANGE_DST_INV) ? "(INV) " : "",
  84                                  NIPQUAD(info->dst_min.ip),
  85                                  NIPQUAD(info->dst_max.ip));
  86                         return false;
  87                 }
  88         }
  89         return true;
  90 }
  91
  92 static inline int
  93 iprange_ipv6_sub(const struct in6_addr *a, const struct in6_addr *b)
  94 {
  95         unsigned int i;
  96         int r;
  97
  98         for (i = 0; i < 4; ++i) {
  99                 r = ntohl(a->s6_addr32[i]) - ntohl(b->s6_addr32[i]);
 100                 if (r != 0)
 101                         return r;
 102         }
 103
 104         return 0;
 105 }
 106
 107 static bool
 108 iprange_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
 109 {
 110         const struct xt_iprange_mtinfo *info = par->matchinfo;
 111         const struct ipv6hdr *iph = ipv6_hdr(skb);
 112         bool m;
 113
 114         if (info->flags & IPRANGE_SRC) {
 115                 m  = iprange_ipv6_sub(&iph->saddr, &info->src_min.in6) < 0;
 116                 m |= iprange_ipv6_sub(&iph->saddr, &info->src_max.in6) > 0;
 117                 m ^= info->flags & IPRANGE_SRC_INV;
 118                 if (m)
 119                         return false;
 120         }
 121         if (info->flags & IPRANGE_DST) {
 122                 m  = iprange_ipv6_sub(&iph->daddr, &info->dst_min.in6) < 0;
 123                 m |= iprange_ipv6_sub(&iph->daddr, &info->dst_max.in6) > 0;
 124                 m ^= info->flags & IPRANGE_DST_INV;
 125                 if (m)
 126                         return false;
 127         }
 128         return true;
 129 }
 130
 131 static struct xt_match iprange_mt_reg[] __read_mostly = {
 132         {
 133                 .name      = "iprange",
 134                 .revision  = 0,
 135                 .family    = NFPROTO_IPV4,
 136                 .match     = iprange_mt_v0,
 137                 .matchsize = sizeof(struct ipt_iprange_info),
 138                 .me        = THIS_MODULE,
 139         },
 140         {
 141                 .name      = "iprange",
 142                 .revision  = 1,
 143                 .family    = NFPROTO_IPV4,
 144                 .match     = iprange_mt4,
 145                 .matchsize = sizeof(struct xt_iprange_mtinfo),
 146                 .me        = THIS_MODULE,
 147         },
 148         {
 149                 .name      = "iprange",
 150                 .revision  = 1,
 151                 .family    = NFPROTO_IPV6,
 152                 .match     = iprange_mt6,
 153                 .matchsize = sizeof(struct xt_iprange_mtinfo),
 154                 .me        = THIS_MODULE,
 155         },
 156 };
 157
 158 static int __init iprange_mt_init(void)
 159 {
 160         return xt_register_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 161 }
 162
 163 static void __exit iprange_mt_exit(void)
 164 {
 165         xt_unregister_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 166 }
 167
 168 module_init(iprange_mt_init);
 169 module_exit(iprange_mt_exit);
 170 MODULE_LICENSE("GPL");
 171 MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>, Jan Engelhardt <jengelh@computergmbh.de>");
 172 MODULE_DESCRIPTION("Xtables: arbitrary IPv4 range matching");
 173 MODULE_ALIAS("ipt_iprange");
 174 MODULE_ALIAS("ip6t_iprange");