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 %pI4 NOT in range %s%pI4-%pI4\n",
  30                                  &iph->saddr,
  31                                  info->flags & IPRANGE_SRC_INV ? "(INV) " : "",
  32                                  &info->src.min_ip,
  33                                  &info->src.max_ip);
  34                         return false;
  35                 }
  36         }
  37         if (info->flags & IPRANGE_DST) {
  38                 if ((ntohl(iph->daddr) < ntohl(info->dst.min_ip)
  39                           || ntohl(iph->daddr) > ntohl(info->dst.max_ip))
  40                          ^ !!(info->flags & IPRANGE_DST_INV)) {
  41                         pr_debug("dst IP %pI4 NOT in range %s%pI4-%pI4\n",
  42                                  &iph->daddr,
  43                                  info->flags & IPRANGE_DST_INV ? "(INV) " : "",
  44                                  &info->dst.min_ip,
  45                                  &info->dst.max_ip);
  46                         return false;
  47                 }
  48         }
  49         return true;
  50 }
  51
  52 static bool
  53 iprange_mt4(const struct sk_buff *skb, const struct xt_match_param *par)
  54 {
  55         const struct xt_iprange_mtinfo *info = par->matchinfo;
  56         const struct iphdr *iph = ip_hdr(skb);
  57         bool m;
  58
  59         if (info->flags & IPRANGE_SRC) {
  60                 m  = ntohl(iph->saddr) < ntohl(info->src_min.ip);
  61                 m |= ntohl(iph->saddr) > ntohl(info->src_max.ip);
  62                 m ^= !!(info->flags & IPRANGE_SRC_INV);
  63                 if (m) {
  64                         pr_debug("src IP %pI4 NOT in range %s%pI4-%pI4\n",
  65                                  &iph->saddr,
  66                                  (info->flags & IPRANGE_SRC_INV) ? "(INV) " : "",
  67                                  &info->src_max.ip,
  68                                  &info->src_max.ip);
  69                         return false;
  70                 }
  71         }
  72         if (info->flags & IPRANGE_DST) {
  73                 m  = ntohl(iph->daddr) < ntohl(info->dst_min.ip);
  74                 m |= ntohl(iph->daddr) > ntohl(info->dst_max.ip);
  75                 m ^= !!(info->flags & IPRANGE_DST_INV);
  76                 if (m) {
  77                         pr_debug("dst IP %pI4 NOT in range %s%pI4-%pI4\n",
  78                                  &iph->daddr,
  79                                  (info->flags & IPRANGE_DST_INV) ? "(INV) " : "",
  80                                  &info->dst_min.ip,
  81                                  &info->dst_max.ip);
  82                         return false;
  83                 }
  84         }
  85         return true;
  86 }
  87
  88 static inline int
  89 iprange_ipv6_sub(const struct in6_addr *a, const struct in6_addr *b)
  90 {
  91         unsigned int i;
  92         int r;
  93
  94         for (i = 0; i < 4; ++i) {
  95                 r = ntohl(a->s6_addr32[i]) - ntohl(b->s6_addr32[i]);
  96                 if (r != 0)
  97                         return r;
  98         }
  99
 100         return 0;
 101 }
 102
 103 static bool
 104 iprange_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
 105 {
 106         const struct xt_iprange_mtinfo *info = par->matchinfo;
 107         const struct ipv6hdr *iph = ipv6_hdr(skb);
 108         bool m;
 109
 110         if (info->flags & IPRANGE_SRC) {
 111                 m  = iprange_ipv6_sub(&iph->saddr, &info->src_min.in6) < 0;
 112                 m |= iprange_ipv6_sub(&iph->saddr, &info->src_max.in6) > 0;
 113                 m ^= !!(info->flags & IPRANGE_SRC_INV);
 114                 if (m)
 115                         return false;
 116         }
 117         if (info->flags & IPRANGE_DST) {
 118                 m  = iprange_ipv6_sub(&iph->daddr, &info->dst_min.in6) < 0;
 119                 m |= iprange_ipv6_sub(&iph->daddr, &info->dst_max.in6) > 0;
 120                 m ^= !!(info->flags & IPRANGE_DST_INV);
 121                 if (m)
 122                         return false;
 123         }
 124         return true;
 125 }
 126
 127 static struct xt_match iprange_mt_reg[] __read_mostly = {
 128         {
 129                 .name      = "iprange",
 130                 .revision  = 0,
 131                 .family    = NFPROTO_IPV4,
 132                 .match     = iprange_mt_v0,
 133                 .matchsize = sizeof(struct ipt_iprange_info),
 134                 .me        = THIS_MODULE,
 135         },
 136         {
 137                 .name      = "iprange",
 138                 .revision  = 1,
 139                 .family    = NFPROTO_IPV4,
 140                 .match     = iprange_mt4,
 141                 .matchsize = sizeof(struct xt_iprange_mtinfo),
 142                 .me        = THIS_MODULE,
 143         },
 144         {
 145                 .name      = "iprange",
 146                 .revision  = 1,
 147                 .family    = NFPROTO_IPV6,
 148                 .match     = iprange_mt6,
 149                 .matchsize = sizeof(struct xt_iprange_mtinfo),
 150                 .me        = THIS_MODULE,
 151         },
 152 };
 153
 154 static int __init iprange_mt_init(void)
 155 {
 156         return xt_register_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 157 }
 158
 159 static void __exit iprange_mt_exit(void)
 160 {
 161         xt_unregister_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 162 }
 163
 164 module_init(iprange_mt_init);
 165 module_exit(iprange_mt_exit);
 166 MODULE_LICENSE("GPL");
 167 MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>, Jan Engelhardt <jengelh@computergmbh.de>");
 168 MODULE_DESCRIPTION("Xtables: arbitrary IPv4 range matching");
 169 MODULE_ALIAS("ipt_iprange");
 170 MODULE_ALIAS("ip6t_iprange");