Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/* Kernel module to match packet length. */

/* (C) 1999-2001 James Morris <jmorros@intercode.com.au>

 *

 * 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/ipv6.h>

#include <net/ip.h>

#include <linux/netfilter/xt_length.h>

#include <linux/netfilter/x_tables.h>

MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");

MODULE_DESCRIPTION("IP tables packet length matching module");

MODULE_LICENSE("GPL");

MODULE_ALIAS("ipt_length");

MODULE_ALIAS("ip6t_length");

static bool

match(const struct sk_buff *skb,

      const struct net_device *in,

      const struct net_device *out,

      const struct xt_match *match,

      const void *matchinfo,

      int offset,

      unsigned int protoff,

      bool *hotdrop)

{

        const struct xt_length_info *info = matchinfo;

        u_int16_t pktlen = ntohs(ip_hdr(skb)->tot_len);

        return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;

}

static bool

match6(const struct sk_buff *skb,

       const struct net_device *in,

       const struct net_device *out,

       const struct xt_match *match,

       const void *matchinfo,

       int offset,

       unsigned int protoff,

       bool *hotdrop)

{

        const struct xt_length_info *info = matchinfo;

        const u_int16_t pktlen = ntohs(ipv6_hdr(skb)->payload_len) +

                                 sizeof(struct ipv6hdr);

        return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;

}

static struct xt_match xt_length_match[] __read_mostly = {

        {

                .name           = "length",

                .family         = AF_INET,

                .match          = match,

                .matchsize      = sizeof(struct xt_length_info),

                .me             = THIS_MODULE,

        },

        {

                .name           = "length",

                .family         = AF_INET6,

                .match          = match6,

                .matchsize      = sizeof(struct xt_length_info),

                .me             = THIS_MODULE,

        },

};

static int __init xt_length_init(void)

{

        return xt_register_matches(xt_length_match,

                                   ARRAY_SIZE(xt_length_match));

}

static void __exit xt_length_fini(void)

{

        xt_unregister_matches(xt_length_match, ARRAY_SIZE(xt_length_match));

}

module_init(xt_length_init);

module_exit(xt_length_fini);