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 #include <linux/in.h>
  13 #include <linux/ip.h>
  14
  15 #include <linux/netfilter/xt_pkttype.h>
  16 #include <linux/netfilter/x_tables.h>
  17
  18 MODULE_LICENSE("GPL");
  19 MODULE_AUTHOR("Michal Ludvig <michal@logix.cz>");
  20 MODULE_DESCRIPTION("IP tables match to match on linklayer packet type");
  21 MODULE_ALIAS("ipt_pkttype");
  22 MODULE_ALIAS("ip6t_pkttype");
  23
  24 static int match(const struct sk_buff *skb,
  25       const struct net_device *in,
  26       const struct net_device *out,
  27       const struct xt_match *match,
  28       const void *matchinfo,
  29       int offset,
  30       unsigned int protoff,
  31       int *hotdrop)
  32 {
  33         u_int8_t type;
  34         const struct xt_pkttype_info *info = matchinfo;
  35
  36         if (skb->pkt_type == PACKET_LOOPBACK)
  37                 type = (MULTICAST(skb->nh.iph->daddr)
  38                         ? PACKET_MULTICAST
  39                         : PACKET_BROADCAST);
  40         else
  41                 type = skb->pkt_type;
  42
  43         return (type == info->pkttype) ^ info->invert;
  44 }
  45
  46 static struct xt_match pkttype_match = {
  47         .name           = "pkttype",
  48         .match          = match,
  49         .matchsize      = sizeof(struct xt_pkttype_info),
  50         .family         = AF_INET,
  51         .me             = THIS_MODULE,
  52 };
  53
  54 static struct xt_match pkttype6_match = {
  55         .name           = "pkttype",
  56         .match          = match,
  57         .matchsize      = sizeof(struct xt_pkttype_info),
  58         .family         = AF_INET6,
  59         .me             = THIS_MODULE,
  60 };
  61
  62 static int __init xt_pkttype_init(void)
  63 {
  64         int ret;
  65         ret = xt_register_match(&pkttype_match);
  66         if (ret)
  67                 return ret;
  68
  69         ret = xt_register_match(&pkttype6_match);
  70         if (ret)
  71                 xt_unregister_match(&pkttype_match);
  72
  73         return ret;
  74 }
  75
  76 static void __exit xt_pkttype_fini(void)
  77 {
  78         xt_unregister_match(&pkttype_match);
  79         xt_unregister_match(&pkttype6_match);
  80 }
  81
  82 module_init(xt_pkttype_init);
  83 module_exit(xt_pkttype_fini);