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_ipv4/ip_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 int
  27 match(const struct sk_buff *skb,
  28       const struct net_device *in,
  29       const struct net_device *out,
  30       const void *matchinfo,
  31       int offset, int *hotdrop)
  32 {
  33         const struct ipt_iprange_info *info = matchinfo;
  34         const struct iphdr *iph = skb->nh.iph;
  35
  36         if (info->flags & IPRANGE_SRC) {
  37                 if (((ntohl(iph->saddr) < ntohl(info->src.min_ip))
  38                           || (ntohl(iph->saddr) > ntohl(info->src.max_ip)))
  39                          ^ !!(info->flags & IPRANGE_SRC_INV)) {
  40                         DEBUGP("src IP %u.%u.%u.%u NOT in range %s"
  41                                "%u.%u.%u.%u-%u.%u.%u.%u\n",
  42                                 NIPQUAD(iph->saddr),
  43                                 info->flags & IPRANGE_SRC_INV ? "(INV) " : "",
  44                                 NIPQUAD(info->src.min_ip),
  45                                 NIPQUAD(info->src.max_ip));
  46                         return 0;
  47                 }
  48         }
  49         if (info->flags & IPRANGE_DST) {
  50                 if (((ntohl(iph->daddr) < ntohl(info->dst.min_ip))
  51                           || (ntohl(iph->daddr) > ntohl(info->dst.max_ip)))
  52                          ^ !!(info->flags & IPRANGE_DST_INV)) {
  53                         DEBUGP("dst IP %u.%u.%u.%u NOT in range %s"
  54                                "%u.%u.%u.%u-%u.%u.%u.%u\n",
  55                                 NIPQUAD(iph->daddr),
  56                                 info->flags & IPRANGE_DST_INV ? "(INV) " : "",
  57                                 NIPQUAD(info->dst.min_ip),
  58                                 NIPQUAD(info->dst.max_ip));
  59                         return 0;
  60                 }
  61         }
  62         return 1;
  63 }
  64
  65 static int check(const char *tablename,
  66                  const struct ipt_ip *ip,
  67                  void *matchinfo,
  68                  unsigned int matchsize,
  69                  unsigned int hook_mask)
  70 {
  71         /* verify size */
  72         if (matchsize != IPT_ALIGN(sizeof(struct ipt_iprange_info)))
  73                 return 0;
  74
  75         return 1;
  76 }
  77
  78 static struct ipt_match iprange_match =
  79 {
  80         .list = { NULL, NULL },
  81         .name = "iprange",
  82         .match = &match,
  83         .checkentry = &check,
  84         .destroy = NULL,
  85         .me = THIS_MODULE
  86 };
  87
  88 static int __init init(void)
  89 {
  90         return ipt_register_match(&iprange_match);
  91 }
  92
  93 static void __exit fini(void)
  94 {
  95         ipt_unregister_match(&iprange_match);
  96 }
  97
  98 module_init(init);
  99 module_exit(fini);