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_ipv4/ipt_iprange.h>
  17
  18 static bool
  19 iprange_mt_v0(const struct sk_buff *skb, const struct net_device *in,
  20               const struct net_device *out, const struct xt_match *match,
  21               const void *matchinfo, int offset, unsigned int protoff,
  22               bool *hotdrop)
  23 {
  24         const struct ipt_iprange_info *info = matchinfo;
  25         const struct iphdr *iph = ip_hdr(skb);
  26
  27         if (info->flags & IPRANGE_SRC) {
  28                 if ((ntohl(iph->saddr) < ntohl(info->src.min_ip)
  29                           || ntohl(iph->saddr) > ntohl(info->src.max_ip))
  30                          ^ !!(info->flags & IPRANGE_SRC_INV)) {
  31                         pr_debug("src IP %u.%u.%u.%u NOT in range %s"
  32                                  "%u.%u.%u.%u-%u.%u.%u.%u\n",
  33                                  NIPQUAD(iph->saddr),
  34                                  info->flags & IPRANGE_SRC_INV ? "(INV) " : "",
  35                                  NIPQUAD(info->src.min_ip),
  36                                  NIPQUAD(info->src.max_ip));
  37                         return false;
  38                 }
  39         }
  40         if (info->flags & IPRANGE_DST) {
  41                 if ((ntohl(iph->daddr) < ntohl(info->dst.min_ip)
  42                           || ntohl(iph->daddr) > ntohl(info->dst.max_ip))
  43                          ^ !!(info->flags & IPRANGE_DST_INV)) {
  44                         pr_debug("dst IP %u.%u.%u.%u NOT in range %s"
  45                                  "%u.%u.%u.%u-%u.%u.%u.%u\n",
  46                                  NIPQUAD(iph->daddr),
  47                                  info->flags & IPRANGE_DST_INV ? "(INV) " : "",
  48                                  NIPQUAD(info->dst.min_ip),
  49                                  NIPQUAD(info->dst.max_ip));
  50                         return false;
  51                 }
  52         }
  53         return true;
  54 }
  55
  56 static bool
  57 iprange_mt4(const struct sk_buff *skb, const struct net_device *in,
  58             const struct net_device *out, const struct xt_match *match,
  59             const void *matchinfo, int offset, unsigned int protoff,
  60             bool *hotdrop)
  61 {
  62         const struct xt_iprange_mtinfo *info = matchinfo;
  63         const struct iphdr *iph = ip_hdr(skb);
  64         bool m;
  65
  66         if (info->flags & IPRANGE_SRC) {
  67                 m  = ntohl(iph->saddr) < ntohl(info->src_min.ip);
  68                 m |= ntohl(iph->saddr) > ntohl(info->src_max.ip);
  69                 m ^= info->flags & IPRANGE_SRC_INV;
  70                 if (m) {
  71                         pr_debug("src IP " NIPQUAD_FMT " NOT in range %s"
  72                                  NIPQUAD_FMT "-" NIPQUAD_FMT "\n",
  73                                  NIPQUAD(iph->saddr),
  74                                  (info->flags & IPRANGE_SRC_INV) ? "(INV) " : "",
  75                                  NIPQUAD(info->src_max.ip),
  76                                  NIPQUAD(info->src_max.ip));
  77                         return false;
  78                 }
  79         }
  80         if (info->flags & IPRANGE_DST) {
  81                 m  = ntohl(iph->daddr) < ntohl(info->dst_min.ip);
  82                 m |= ntohl(iph->daddr) > ntohl(info->dst_max.ip);
  83                 m ^= info->flags & IPRANGE_DST_INV;
  84                 if (m) {
  85                         pr_debug("dst IP " NIPQUAD_FMT " NOT in range %s"
  86                                  NIPQUAD_FMT "-" NIPQUAD_FMT "\n",
  87                                  NIPQUAD(iph->daddr),
  88                                  (info->flags & IPRANGE_DST_INV) ? "(INV) " : "",
  89                                  NIPQUAD(info->dst_min.ip),
  90                                  NIPQUAD(info->dst_max.ip));
  91                         return false;
  92                 }
  93         }
  94         return true;
  95 }
  96
  97 static inline int
  98 iprange_ipv6_sub(const struct in6_addr *a, const struct in6_addr *b)
  99 {
 100         unsigned int i;
 101         int r;
 102
 103         for (i = 0; i < 4; ++i) {
 104                 r = (__force u32)a->s6_addr32[i] - (__force u32)b->s6_addr32[i];
 105                 if (r != 0)
 106                         return r;
 107         }
 108
 109         return 0;
 110 }
 111
 112 static bool
 113 iprange_mt6(const struct sk_buff *skb, const struct net_device *in,
 114             const struct net_device *out, const struct xt_match *match,
 115             const void *matchinfo, int offset, unsigned int protoff,
 116             bool *hotdrop)
 117 {
 118         const struct xt_iprange_mtinfo *info = matchinfo;
 119         const struct ipv6hdr *iph = ipv6_hdr(skb);
 120         bool m;
 121
 122         if (info->flags & IPRANGE_SRC) {
 123                 m  = iprange_ipv6_sub(&iph->saddr, &info->src_min.in6) < 0;
 124                 m |= iprange_ipv6_sub(&iph->saddr, &info->src_max.in6) > 0;
 125                 m ^= info->flags & IPRANGE_SRC_INV;
 126                 if (m)
 127                         return false;
 128         }
 129         if (info->flags & IPRANGE_DST) {
 130                 m  = iprange_ipv6_sub(&iph->daddr, &info->dst_min.in6) < 0;
 131                 m |= iprange_ipv6_sub(&iph->daddr, &info->dst_max.in6) > 0;
 132                 m ^= info->flags & IPRANGE_DST_INV;
 133                 if (m)
 134                         return false;
 135         }
 136         return true;
 137 }
 138
 139 static struct xt_match iprange_mt_reg[] __read_mostly = {
 140         {
 141                 .name      = "iprange",
 142                 .revision  = 0,
 143                 .family    = AF_INET,
 144                 .match     = iprange_mt_v0,
 145                 .matchsize = sizeof(struct ipt_iprange_info),
 146                 .me        = THIS_MODULE,
 147         },
 148         {
 149                 .name      = "iprange",
 150                 .revision  = 1,
 151                 .family    = AF_INET6,
 152                 .match     = iprange_mt4,
 153                 .matchsize = sizeof(struct xt_iprange_mtinfo),
 154                 .me        = THIS_MODULE,
 155         },
 156         {
 157                 .name      = "iprange",
 158                 .revision  = 1,
 159                 .family    = AF_INET6,
 160                 .match     = iprange_mt6,
 161                 .matchsize = sizeof(struct xt_iprange_mtinfo),
 162                 .me        = THIS_MODULE,
 163         },
 164 };
 165
 166 static int __init iprange_mt_init(void)
 167 {
 168         return xt_register_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 169 }
 170
 171 static void __exit iprange_mt_exit(void)
 172 {
 173         xt_unregister_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 174 }
 175
 176 module_init(iprange_mt_init);
 177 module_exit(iprange_mt_exit);
 178 MODULE_LICENSE("GPL");
 179 MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>, Jan Engelhardt <jengelh@computergmbh.de>");
 180 MODULE_DESCRIPTION("Xtables: arbitrary IPv4 range matching");