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 #include <linux/ipv6.h>
  15
  16 #include <linux/netfilter/xt_pkttype.h>
  17 #include <linux/netfilter/x_tables.h>
  18
  19 MODULE_LICENSE("GPL");
  20 MODULE_AUTHOR("Michal Ludvig <michal@logix.cz>");
  21 MODULE_DESCRIPTION("Xtables: link layer packet type match");
  22 MODULE_ALIAS("ipt_pkttype");
  23 MODULE_ALIAS("ip6t_pkttype");
  24
  25 static bool
  26 pkttype_mt(const struct sk_buff *skb, struct xt_action_param *par)
  27 {
  28         const struct xt_pkttype_info *info = par->matchinfo;
  29         u_int8_t type;
  30
  31         if (skb->pkt_type != PACKET_LOOPBACK)
  32                 type = skb->pkt_type;
  33         else if (xt_family(par) == NFPROTO_IPV4 &&
  34             ipv4_is_multicast(ip_hdr(skb)->daddr))
  35                 type = PACKET_MULTICAST;
  36         else if (xt_family(par) == NFPROTO_IPV6)
  37                 type = PACKET_MULTICAST;
  38         else
  39                 type = PACKET_BROADCAST;
  40
  41         return (type == info->pkttype) ^ info->invert;
  42 }
  43
  44 static struct xt_match pkttype_mt_reg __read_mostly = {
  45         .name      = "pkttype",
  46         .revision  = 0,
  47         .family    = NFPROTO_UNSPEC,
  48         .match     = pkttype_mt,
  49         .matchsize = sizeof(struct xt_pkttype_info),
  50         .me        = THIS_MODULE,
  51 };
  52
  53 static int __init pkttype_mt_init(void)
  54 {
  55         return xt_register_match(&pkttype_mt_reg);
  56 }
  57
  58 static void __exit pkttype_mt_exit(void)
  59 {
  60         xt_unregister_match(&pkttype_mt_reg);
  61 }
  62
  63 module_init(pkttype_mt_init);
  64 module_exit(pkttype_mt_exit);