net/ipv4/netfilter/ipt_iprange.c

   1 /*
   2  * iptables module to match IP address ranges
   3  *
   4  * (C) 2003 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/module.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/ip.h>
  13 #include <linux/netfilter/x_tables.h>
  14 #include <linux/netfilter_ipv4/ipt_iprange.h>
  15
  16 MODULE_LICENSE("GPL");
  17 MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>");
  18 MODULE_DESCRIPTION("Xtables: arbitrary IPv4 range matching");
  19
  20 static bool
  21 iprange_mt(const struct sk_buff *skb, const struct net_device *in,
  22            const struct net_device *out, const struct xt_match *match,
  23            const void *matchinfo, int offset, unsigned int protoff,
  24            bool *hotdrop)
  25 {
  26         const struct ipt_iprange_info *info = matchinfo;
  27         const struct iphdr *iph = ip_hdr(skb);
  28
  29         if (info->flags & IPRANGE_SRC) {
  30                 if ((ntohl(iph->saddr) < ntohl(info->src.min_ip)
  31                           || ntohl(iph->saddr) > ntohl(info->src.max_ip))
  32                          ^ !!(info->flags & IPRANGE_SRC_INV)) {
  33                         pr_debug("src IP %u.%u.%u.%u NOT in range %s"
  34                                  "%u.%u.%u.%u-%u.%u.%u.%u\n",
  35                                  NIPQUAD(iph->saddr),
  36                                  info->flags & IPRANGE_SRC_INV ? "(INV) " : "",
  37                                  NIPQUAD(info->src.min_ip),
  38                                  NIPQUAD(info->src.max_ip));
  39                         return false;
  40                 }
  41         }
  42         if (info->flags & IPRANGE_DST) {
  43                 if ((ntohl(iph->daddr) < ntohl(info->dst.min_ip)
  44                           || ntohl(iph->daddr) > ntohl(info->dst.max_ip))
  45                          ^ !!(info->flags & IPRANGE_DST_INV)) {
  46                         pr_debug("dst IP %u.%u.%u.%u NOT in range %s"
  47                                  "%u.%u.%u.%u-%u.%u.%u.%u\n",
  48                                  NIPQUAD(iph->daddr),
  49                                  info->flags & IPRANGE_DST_INV ? "(INV) " : "",
  50                                  NIPQUAD(info->dst.min_ip),
  51                                  NIPQUAD(info->dst.max_ip));
  52                         return false;
  53                 }
  54         }
  55         return true;
  56 }
  57
  58 static struct xt_match iprange_mt_reg __read_mostly = {
  59         .name           = "iprange",
  60         .family         = AF_INET,
  61         .match          = iprange_mt,
  62         .matchsize      = sizeof(struct ipt_iprange_info),
  63         .me             = THIS_MODULE
  64 };
  65
  66 static int __init iprange_mt_init(void)
  67 {
  68         return xt_register_match(&iprange_mt_reg);
  69 }
  70
  71 static void __exit iprange_mt_exit(void)
  72 {
  73         xt_unregister_match(&iprange_mt_reg);
  74 }
  75
  76 module_init(iprange_mt_init);
  77 module_exit(iprange_mt_exit);