net/ipv4/netfilter/ipt_realm.c

   1 /* IP tables module for matching the routing realm
   2  *
   3  * $Id: ipt_realm.c,v 1.3 2004/03/05 13:25:40 laforge Exp $
   4  *
   5  * (C) 2003 by Sampsa Ranta <sampsa@netsonic.fi>
   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
  12 #include <linux/module.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/netdevice.h>
  15 #include <net/route.h>
  16
  17 #include <linux/netfilter_ipv4/ipt_realm.h>
  18 #include <linux/netfilter_ipv4/ip_tables.h>
  19
  20 MODULE_AUTHOR("Sampsa Ranta <sampsa@netsonic.fi>");
  21 MODULE_LICENSE("GPL");
  22 MODULE_DESCRIPTION("iptables realm match");
  23
  24 static int
  25 match(const struct sk_buff *skb,
  26       const struct net_device *in,
  27       const struct net_device *out,
  28       const void *matchinfo,
  29       int offset,
  30       int *hotdrop)
  31 {
  32         const struct ipt_realm_info *info = matchinfo;
  33         struct dst_entry *dst = skb->dst;
  34
  35         return (info->id == (dst->tclassid & info->mask)) ^ info->invert;
  36 }
  37
  38 static int check(const char *tablename,
  39                  const struct ipt_ip *ip,
  40                  void *matchinfo,
  41                  unsigned int matchsize,
  42                  unsigned int hook_mask)
  43 {
  44         if (hook_mask
  45             & ~((1 << NF_IP_POST_ROUTING) | (1 << NF_IP_FORWARD) |
  46                 (1 << NF_IP_LOCAL_OUT) | (1 << NF_IP_LOCAL_IN))) {
  47                 printk("ipt_realm: only valid for POST_ROUTING, LOCAL_OUT, "
  48                        "LOCAL_IN or FORWARD.\n");
  49                 return 0;
  50         }
  51         if (matchsize != IPT_ALIGN(sizeof(struct ipt_realm_info))) {
  52                 printk("ipt_realm: invalid matchsize.\n");
  53                 return 0;
  54         }
  55         return 1;
  56 }
  57
  58 static struct ipt_match realm_match = {
  59         .name           = "realm",
  60         .match          = match,
  61         .checkentry     = check,
  62         .me             = THIS_MODULE
  63 };
  64
  65 static int __init init(void)
  66 {
  67         return ipt_register_match(&realm_match);
  68 }
  69
  70 static void __exit fini(void)
  71 {
  72         ipt_unregister_match(&realm_match);
  73 }
  74
  75 module_init(init);
  76 module_exit(fini);