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("iptables arbitrary IP range match module");
  19
  20 static bool
  21 match(const struct sk_buff *skb,
  22       const struct net_device *in,
  23       const struct net_device *out,
  24       const struct xt_match *match,
  25       const void *matchinfo,
  26       int offset, unsigned int protoff, bool *hotdrop)
  27 {
  28         const struct ipt_iprange_info *info = matchinfo;
  29         const struct iphdr *iph = ip_hdr(skb);
  30
  31         if (info->flags & IPRANGE_SRC) {
  32                 if ((ntohl(iph->saddr) < ntohl(info->src.min_ip)
  33                           || ntohl(iph->saddr) > ntohl(info->src.max_ip))
  34                          ^ !!(info->flags & IPRANGE_SRC_INV)) {
  35                         pr_debug("src IP %u.%u.%u.%u NOT in range %s"
  36                                  "%u.%u.%u.%u-%u.%u.%u.%u\n",
  37                                  NIPQUAD(iph->saddr),
  38                                  info->flags & IPRANGE_SRC_INV ? "(INV) " : "",
  39                                  NIPQUAD(info->src.min_ip),
  40                                  NIPQUAD(info->src.max_ip));
  41                         return false;
  42                 }
  43         }
  44         if (info->flags & IPRANGE_DST) {
  45                 if ((ntohl(iph->daddr) < ntohl(info->dst.min_ip)
  46                           || ntohl(iph->daddr) > ntohl(info->dst.max_ip))
  47                          ^ !!(info->flags & IPRANGE_DST_INV)) {
  48                         pr_debug("dst IP %u.%u.%u.%u NOT in range %s"
  49                                  "%u.%u.%u.%u-%u.%u.%u.%u\n",
  50                                  NIPQUAD(iph->daddr),
  51                                  info->flags & IPRANGE_DST_INV ? "(INV) " : "",
  52                                  NIPQUAD(info->dst.min_ip),
  53                                  NIPQUAD(info->dst.max_ip));
  54                         return false;
  55                 }
  56         }
  57         return true;
  58 }
  59
  60 static struct xt_match iprange_match __read_mostly = {
  61         .name           = "iprange",
  62         .family         = AF_INET,
  63         .match          = match,
  64         .matchsize      = sizeof(struct ipt_iprange_info),
  65         .me             = THIS_MODULE
  66 };
  67
  68 static int __init ipt_iprange_init(void)
  69 {
  70         return xt_register_match(&iprange_match);
  71 }
  72
  73 static void __exit ipt_iprange_fini(void)
  74 {
  75         xt_unregister_match(&iprange_match);
  76 }
  77
  78 module_init(ipt_iprange_init);
  79 module_exit(ipt_iprange_fini);