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 net_device *in,
  21               const struct net_device *out, const struct xt_match *match,
  22               const void *matchinfo, int offset, unsigned int protoff,
  23               bool *hotdrop)
  24 {
  25         const struct ipt_iprange_info *info = matchinfo;
  26         const struct iphdr *iph = ip_hdr(skb);
  27
  28         if (info->flags & IPRANGE_SRC) {
  29                 if ((ntohl(iph->saddr) < ntohl(info->src.min_ip)
  30                           || ntohl(iph->saddr) > ntohl(info->src.max_ip))
  31                          ^ !!(info->flags & IPRANGE_SRC_INV)) {
  32                         pr_debug("src IP %u.%u.%u.%u NOT in range %s"
  33                                  "%u.%u.%u.%u-%u.%u.%u.%u\n",
  34                                  NIPQUAD(iph->saddr),
  35                                  info->flags & IPRANGE_SRC_INV ? "(INV) " : "",
  36                                  NIPQUAD(info->src.min_ip),
  37                                  NIPQUAD(info->src.max_ip));
  38                         return false;
  39                 }
  40         }
  41         if (info->flags & IPRANGE_DST) {
  42                 if ((ntohl(iph->daddr) < ntohl(info->dst.min_ip)
  43                           || ntohl(iph->daddr) > ntohl(info->dst.max_ip))
  44                          ^ !!(info->flags & IPRANGE_DST_INV)) {
  45                         pr_debug("dst IP %u.%u.%u.%u NOT in range %s"
  46                                  "%u.%u.%u.%u-%u.%u.%u.%u\n",
  47                                  NIPQUAD(iph->daddr),
  48                                  info->flags & IPRANGE_DST_INV ? "(INV) " : "",
  49                                  NIPQUAD(info->dst.min_ip),
  50                                  NIPQUAD(info->dst.max_ip));
  51                         return false;
  52                 }
  53         }
  54         return true;
  55 }
  56
  57 static bool
  58 iprange_mt4(const struct sk_buff *skb, const struct net_device *in,
  59             const struct net_device *out, const struct xt_match *match,
  60             const void *matchinfo, int offset, unsigned int protoff,
  61             bool *hotdrop)
  62 {
  63         const struct xt_iprange_mtinfo *info = matchinfo;
  64         const struct iphdr *iph = ip_hdr(skb);
  65         bool m;
  66
  67         if (info->flags & IPRANGE_SRC) {
  68                 m  = ntohl(iph->saddr) < ntohl(info->src_min.ip);
  69                 m |= ntohl(iph->saddr) > ntohl(info->src_max.ip);
  70                 m ^= info->flags & IPRANGE_SRC_INV;
  71                 if (m) {
  72                         pr_debug("src IP " NIPQUAD_FMT " NOT in range %s"
  73                                  NIPQUAD_FMT "-" NIPQUAD_FMT "\n",
  74                                  NIPQUAD(iph->saddr),
  75                                  (info->flags & IPRANGE_SRC_INV) ? "(INV) " : "",
  76                                  NIPQUAD(info->src_max.ip),
  77                                  NIPQUAD(info->src_max.ip));
  78                         return false;
  79                 }
  80         }
  81         if (info->flags & IPRANGE_DST) {
  82                 m  = ntohl(iph->daddr) < ntohl(info->dst_min.ip);
  83                 m |= ntohl(iph->daddr) > ntohl(info->dst_max.ip);
  84                 m ^= info->flags & IPRANGE_DST_INV;
  85                 if (m) {
  86                         pr_debug("dst IP " NIPQUAD_FMT " NOT in range %s"
  87                                  NIPQUAD_FMT "-" NIPQUAD_FMT "\n",
  88                                  NIPQUAD(iph->daddr),
  89                                  (info->flags & IPRANGE_DST_INV) ? "(INV) " : "",
  90                                  NIPQUAD(info->dst_min.ip),
  91                                  NIPQUAD(info->dst_max.ip));
  92                         return false;
  93                 }
  94         }
  95         return true;
  96 }
  97
  98 static inline int
  99 iprange_ipv6_sub(const struct in6_addr *a, const struct in6_addr *b)
 100 {
 101         unsigned int i;
 102         int r;
 103
 104         for (i = 0; i < 4; ++i) {
 105                 r = ntohl(a->s6_addr32[i]) - ntohl(b->s6_addr32[i]);
 106                 if (r != 0)
 107                         return r;
 108         }
 109
 110         return 0;
 111 }
 112
 113 static bool
 114 iprange_mt6(const struct sk_buff *skb, const struct net_device *in,
 115             const struct net_device *out, const struct xt_match *match,
 116             const void *matchinfo, int offset, unsigned int protoff,
 117             bool *hotdrop)
 118 {
 119         const struct xt_iprange_mtinfo *info = matchinfo;
 120         const struct ipv6hdr *iph = ipv6_hdr(skb);
 121         bool m;
 122
 123         if (info->flags & IPRANGE_SRC) {
 124                 m  = iprange_ipv6_sub(&iph->saddr, &info->src_min.in6) < 0;
 125                 m |= iprange_ipv6_sub(&iph->saddr, &info->src_max.in6) > 0;
 126                 m ^= info->flags & IPRANGE_SRC_INV;
 127                 if (m)
 128                         return false;
 129         }
 130         if (info->flags & IPRANGE_DST) {
 131                 m  = iprange_ipv6_sub(&iph->daddr, &info->dst_min.in6) < 0;
 132                 m |= iprange_ipv6_sub(&iph->daddr, &info->dst_max.in6) > 0;
 133                 m ^= info->flags & IPRANGE_DST_INV;
 134                 if (m)
 135                         return false;
 136         }
 137         return true;
 138 }
 139
 140 static struct xt_match iprange_mt_reg[] __read_mostly = {
 141         {
 142                 .name      = "iprange",
 143                 .revision  = 0,
 144                 .family    = AF_INET,
 145                 .match     = iprange_mt_v0,
 146                 .matchsize = sizeof(struct ipt_iprange_info),
 147                 .me        = THIS_MODULE,
 148         },
 149         {
 150                 .name      = "iprange",
 151                 .revision  = 1,
 152                 .family    = AF_INET,
 153                 .match     = iprange_mt4,
 154                 .matchsize = sizeof(struct xt_iprange_mtinfo),
 155                 .me        = THIS_MODULE,
 156         },
 157         {
 158                 .name      = "iprange",
 159                 .revision  = 1,
 160                 .family    = AF_INET6,
 161                 .match     = iprange_mt6,
 162                 .matchsize = sizeof(struct xt_iprange_mtinfo),
 163                 .me        = THIS_MODULE,
 164         },
 165 };
 166
 167 static int __init iprange_mt_init(void)
 168 {
 169         return xt_register_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 170 }
 171
 172 static void __exit iprange_mt_exit(void)
 173 {
 174         xt_unregister_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 175 }
 176
 177 module_init(iprange_mt_init);
 178 module_exit(iprange_mt_exit);
 179 MODULE_LICENSE("GPL");
 180 MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>, Jan Engelhardt <jengelh@computergmbh.de>");
 181 MODULE_DESCRIPTION("Xtables: arbitrary IPv4 range matching");
 182 MODULE_ALIAS("ipt_iprange");
 183 MODULE_ALIAS("ip6t_iprange");