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, const struct xt_match_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 (par->match->family == NFPROTO_IPV4 &&
  34             ipv4_is_multicast(ip_hdr(skb)->daddr))
  35                 type = PACKET_MULTICAST;
  36         else if (par->match->family == NFPROTO_IPV6 &&
  37             ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
  38                 type = PACKET_MULTICAST;
  39         else
  40                 type = PACKET_BROADCAST;
  41
  42         return (type == info->pkttype) ^ info->invert;
  43 }
  44
  45 static struct xt_match pkttype_mt_reg[] __read_mostly = {
  46         {
  47                 .name           = "pkttype",
  48                 .family         = NFPROTO_IPV4,
  49                 .match          = pkttype_mt,
  50                 .matchsize      = sizeof(struct xt_pkttype_info),
  51                 .me             = THIS_MODULE,
  52         },
  53         {
  54                 .name           = "pkttype",
  55                 .family         = NFPROTO_IPV6,
  56                 .match          = pkttype_mt,
  57                 .matchsize      = sizeof(struct xt_pkttype_info),
  58                 .me             = THIS_MODULE,
  59         },
  60 };
  61
  62 static int __init pkttype_mt_init(void)
  63 {
  64         return xt_register_matches(pkttype_mt_reg, ARRAY_SIZE(pkttype_mt_reg));
  65 }
  66
  67 static void __exit pkttype_mt_exit(void)
  68 {
  69         xt_unregister_matches(pkttype_mt_reg, ARRAY_SIZE(pkttype_mt_reg));
  70 }
  71
  72 module_init(pkttype_mt_init);
  73 module_exit(pkttype_mt_exit);