linux/net/netfilter/xt_pkttype.c
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   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
  19MODULE_LICENSE("GPL");
  20MODULE_AUTHOR("Michal Ludvig <michal@logix.cz>");
  21MODULE_DESCRIPTION("Xtables: link layer packet type match");
  22MODULE_ALIAS("ipt_pkttype");
  23MODULE_ALIAS("ip6t_pkttype");
  24
  25static bool
  26pkttype_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 (par->family == NFPROTO_IPV4 &&
  34            ipv4_is_multicast(ip_hdr(skb)->daddr))
  35                type = PACKET_MULTICAST;
  36        else if (par->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
  45static struct xt_match pkttype_mt_reg __read_mostly = {
  46        .name      = "pkttype",
  47        .revision  = 0,
  48        .family    = NFPROTO_UNSPEC,
  49        .match     = pkttype_mt,
  50        .matchsize = sizeof(struct xt_pkttype_info),
  51        .me        = THIS_MODULE,
  52};
  53
  54static int __init pkttype_mt_init(void)
  55{
  56        return xt_register_match(&pkttype_mt_reg);
  57}
  58
  59static void __exit pkttype_mt_exit(void)
  60{
  61        xt_unregister_match(&pkttype_mt_reg);
  62}
  63
  64module_init(pkttype_mt_init);
  65module_exit(pkttype_mt_exit);
  66
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