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 net_device *in,
  27            const struct net_device *out, const struct xt_match *match,
  28            const void *matchinfo, int offset, unsigned int protoff,
  29            bool *hotdrop)
  30 {
  31         const struct xt_pkttype_info *info = matchinfo;
  32         u_int8_t type;
  33
  34         if (skb->pkt_type != PACKET_LOOPBACK)
  35                 type = skb->pkt_type;
  36         else if (match->family == AF_INET &&
  37             ipv4_is_multicast(ip_hdr(skb)->daddr))
  38                 type = PACKET_MULTICAST;
  39         else if (match->family == AF_INET6 &&
  40             ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
  41                 type = PACKET_MULTICAST;
  42         else
  43                 type = PACKET_BROADCAST;
  44
  45         return (type == info->pkttype) ^ info->invert;
  46 }
  47
  48 static struct xt_match pkttype_mt_reg[] __read_mostly = {
  49         {
  50                 .name           = "pkttype",
  51                 .family         = AF_INET,
  52                 .match          = pkttype_mt,
  53                 .matchsize      = sizeof(struct xt_pkttype_info),
  54                 .me             = THIS_MODULE,
  55         },
  56         {
  57                 .name           = "pkttype",
  58                 .family         = AF_INET6,
  59                 .match          = pkttype_mt,
  60                 .matchsize      = sizeof(struct xt_pkttype_info),
  61                 .me             = THIS_MODULE,
  62         },
  63 };
  64
  65 static int __init pkttype_mt_init(void)
  66 {
  67         return xt_register_matches(pkttype_mt_reg, ARRAY_SIZE(pkttype_mt_reg));
  68 }
  69
  70 static void __exit pkttype_mt_exit(void)
  71 {
  72         xt_unregister_matches(pkttype_mt_reg, ARRAY_SIZE(pkttype_mt_reg));
  73 }
  74
  75 module_init(pkttype_mt_init);
  76 module_exit(pkttype_mt_exit);