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 #if 0
  21 #define DEBUGP printk
  22 #else
  23 #define DEBUGP(format, args...)
  24 #endif
  25
  26 static bool
  27 match(const struct sk_buff *skb,
  28       const struct net_device *in,
  29       const struct net_device *out,
  30       const struct xt_match *match,
  31       const void *matchinfo,
  32       int offset, unsigned int protoff, bool *hotdrop)
  33 {
  34         const struct ipt_iprange_info *info = matchinfo;
  35         const struct iphdr *iph = ip_hdr(skb);
  36
  37         if (info->flags & IPRANGE_SRC) {
  38                 if (((ntohl(iph->saddr) < ntohl(info->src.min_ip))
  39                           || (ntohl(iph->saddr) > ntohl(info->src.max_ip)))
  40                          ^ !!(info->flags & IPRANGE_SRC_INV)) {
  41                         DEBUGP("src IP %u.%u.%u.%u NOT in range %s"
  42                                "%u.%u.%u.%u-%u.%u.%u.%u\n",
  43                                 NIPQUAD(iph->saddr),
  44                                 info->flags & IPRANGE_SRC_INV ? "(INV) " : "",
  45                                 NIPQUAD(info->src.min_ip),
  46                                 NIPQUAD(info->src.max_ip));
  47                         return false;
  48                 }
  49         }
  50         if (info->flags & IPRANGE_DST) {
  51                 if (((ntohl(iph->daddr) < ntohl(info->dst.min_ip))
  52                           || (ntohl(iph->daddr) > ntohl(info->dst.max_ip)))
  53                          ^ !!(info->flags & IPRANGE_DST_INV)) {
  54                         DEBUGP("dst IP %u.%u.%u.%u NOT in range %s"
  55                                "%u.%u.%u.%u-%u.%u.%u.%u\n",
  56                                 NIPQUAD(iph->daddr),
  57                                 info->flags & IPRANGE_DST_INV ? "(INV) " : "",
  58                                 NIPQUAD(info->dst.min_ip),
  59                                 NIPQUAD(info->dst.max_ip));
  60                         return false;
  61                 }
  62         }
  63         return true;
  64 }
  65
  66 static struct xt_match iprange_match = {
  67         .name           = "iprange",
  68         .family         = AF_INET,
  69         .match          = match,
  70         .matchsize      = sizeof(struct ipt_iprange_info),
  71         .me             = THIS_MODULE
  72 };
  73
  74 static int __init ipt_iprange_init(void)
  75 {
  76         return xt_register_match(&iprange_match);
  77 }
  78
  79 static void __exit ipt_iprange_fini(void)
  80 {
  81         xt_unregister_match(&iprange_match);
  82 }
  83
  84 module_init(ipt_iprange_init);
  85 module_exit(ipt_iprange_fini);