root/net/netfilter/xt_pkttype.c

DEFINITIONS

1. pkttype_mt
2. pkttype_mt_init
3. pkttype_mt_exit

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* (C) 1999-2001 Michal Ludvig <michal@logix.cz>
   3  */
   4 
   5 #include <linux/module.h>
   6 #include <linux/skbuff.h>
   7 #include <linux/if_ether.h>
   8 #include <linux/if_packet.h>
   9 #include <linux/in.h>
  10 #include <linux/ip.h>
  11 #include <linux/ipv6.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("Xtables: link layer packet type match");
  19 MODULE_ALIAS("ipt_pkttype");
  20 MODULE_ALIAS("ip6t_pkttype");
  21 
  22 static bool
  23 pkttype_mt(const struct sk_buff *skb, struct xt_action_param *par)
  24 {
  25         const struct xt_pkttype_info *info = par->matchinfo;
  26         u_int8_t type;
  27 
  28         if (skb->pkt_type != PACKET_LOOPBACK)
  29                 type = skb->pkt_type;
  30         else if (xt_family(par) == NFPROTO_IPV4 &&
  31             ipv4_is_multicast(ip_hdr(skb)->daddr))
  32                 type = PACKET_MULTICAST;
  33         else if (xt_family(par) == NFPROTO_IPV6)
  34                 type = PACKET_MULTICAST;
  35         else
  36                 type = PACKET_BROADCAST;
  37 
  38         return (type == info->pkttype) ^ info->invert;
  39 }
  40 
  41 static struct xt_match pkttype_mt_reg __read_mostly = {
  42         .name      = "pkttype",
  43         .revision  = 0,
  44         .family    = NFPROTO_UNSPEC,
  45         .match     = pkttype_mt,
  46         .matchsize = sizeof(struct xt_pkttype_info),
  47         .me        = THIS_MODULE,
  48 };
  49 
  50 static int __init pkttype_mt_init(void)
  51 {
  52         return xt_register_match(&pkttype_mt_reg);
  53 }
  54 
  55 static void __exit pkttype_mt_exit(void)
  56 {
  57         xt_unregister_match(&pkttype_mt_reg);
  58 }
  59 
  60 module_init(pkttype_mt_init);
  61 module_exit(pkttype_mt_exit);