net/netfilter/xt_pkttype.c

   1 /* (C) 1999-2001 Michal Ludvig <michal@logix.cz>
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License version 2 as
   5  * published by the Free Software Foundation.
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/skbuff.h>
  10 #include <linux/if_ether.h>
  11 #include <linux/if_packet.h>
  12
  13 #include <linux/netfilter/xt_pkttype.h>
  14 #include <linux/netfilter/x_tables.h>
  15
  16 MODULE_LICENSE("GPL");
  17 MODULE_AUTHOR("Michal Ludvig <michal@logix.cz>");
  18 MODULE_DESCRIPTION("IP tables match to match on linklayer packet type");
  19 MODULE_ALIAS("ipt_pkttype");
  20 MODULE_ALIAS("ip6t_pkttype");
  21
  22 static int match(const struct sk_buff *skb,
  23       const struct net_device *in,
  24       const struct net_device *out,
  25       const void *matchinfo,
  26       int offset,
  27       unsigned int protoff,
  28       int *hotdrop)
  29 {
  30         const struct xt_pkttype_info *info = matchinfo;
  31
  32         return (skb->pkt_type == info->pkttype) ^ info->invert;
  33 }
  34
  35 static int checkentry(const char *tablename,
  36                    const void *ip,
  37                    void *matchinfo,
  38                    unsigned int matchsize,
  39                    unsigned int hook_mask)
  40 {
  41         if (matchsize != XT_ALIGN(sizeof(struct xt_pkttype_info)))
  42                 return 0;
  43
  44         return 1;
  45 }
  46
  47 static struct xt_match pkttype_match = {
  48         .name           = "pkttype",
  49         .match          = &match,
  50         .checkentry     = &checkentry,
  51         .me             = THIS_MODULE,
  52 };
  53 static struct xt_match pkttype6_match = {
  54         .name           = "pkttype",
  55         .match          = &match,
  56         .checkentry     = &checkentry,
  57         .me             = THIS_MODULE,
  58 };
  59
  60
  61 static int __init init(void)
  62 {
  63         int ret;
  64         ret = xt_register_match(AF_INET, &pkttype_match);
  65         if (ret)
  66                 return ret;
  67
  68         ret = xt_register_match(AF_INET6, &pkttype6_match);
  69         if (ret)
  70                 xt_unregister_match(AF_INET, &pkttype_match);
  71
  72         return ret;
  73 }
  74
  75 static void __exit fini(void)
  76 {
  77         xt_unregister_match(AF_INET, &pkttype_match);
  78         xt_unregister_match(AF_INET6, &pkttype6_match);
  79 }
  80
  81 module_init(init);
  82 module_exit(fini);