root/net/netfilter/xt_pkttype.c

DEFINITIONS

1. pkttype_mt
2. pkttype_mt_init
3. pkttype_mt_exit

/* (C) 1999-2001 Michal Ludvig <michal@logix.cz>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/ipv6.h>

#include <linux/netfilter/xt_pkttype.h>
#include <linux/netfilter/x_tables.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michal Ludvig <michal@logix.cz>");
MODULE_DESCRIPTION("Xtables: link layer packet type match");
MODULE_ALIAS("ipt_pkttype");
MODULE_ALIAS("ip6t_pkttype");

static bool
pkttype_mt(const struct sk_buff *skb, const struct xt_match_param *par)
{
        const struct xt_pkttype_info *info = par->matchinfo;
        u_int8_t type;

        if (skb->pkt_type != PACKET_LOOPBACK)
                type = skb->pkt_type;
        else if (par->family == NFPROTO_IPV4 &&
            ipv4_is_multicast(ip_hdr(skb)->daddr))
                type = PACKET_MULTICAST;
        else if (par->family == NFPROTO_IPV6 &&
            ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
                type = PACKET_MULTICAST;
        else
                type = PACKET_BROADCAST;

        return (type == info->pkttype) ^ info->invert;
}

static struct xt_match pkttype_mt_reg __read_mostly = {
        .name      = "pkttype",
        .revision  = 0,
        .family    = NFPROTO_UNSPEC,
        .match     = pkttype_mt,
        .matchsize = sizeof(struct xt_pkttype_info),
        .me        = THIS_MODULE,
};

static int __init pkttype_mt_init(void)
{
        return xt_register_match(&pkttype_mt_reg);
}

static void __exit pkttype_mt_exit(void)
{
        xt_unregister_match(&pkttype_mt_reg);
}

module_init(pkttype_mt_init);
module_exit(pkttype_mt_exit);