Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/* NETMAP - static NAT mapping of IP network addresses (1:1).

 * The mapping can be applied to source (POSTROUTING),

 * destination (PREROUTING), or both (with separate rules).

 */

/* (C) 2000-2001 Svenning Soerensen <svenning@post5.tele.dk>

 *

 * 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/ip.h>

#include <linux/module.h>

#include <linux/netdevice.h>

#include <linux/netfilter.h>

#include <linux/netfilter_ipv4.h>

#include <linux/netfilter/x_tables.h>

#include <net/netfilter/nf_nat_rule.h>

MODULE_LICENSE("GPL");

MODULE_AUTHOR("Svenning Soerensen <svenning@post5.tele.dk>");

MODULE_DESCRIPTION("iptables 1:1 NAT mapping of IP networks target");

static bool

check(const char *tablename,

      const void *e,

      const struct xt_target *target,

      void *targinfo,

      unsigned int hook_mask)

{

        const struct nf_nat_multi_range_compat *mr = targinfo;

        if (!(mr->range[0].flags & IP_NAT_RANGE_MAP_IPS)) {

                pr_debug("NETMAP:check: bad MAP_IPS.\n");

                return false;

        }

        if (mr->rangesize != 1) {

                pr_debug("NETMAP:check: bad rangesize %u.\n", mr->rangesize);

                return false;

        }

        return true;

}

static unsigned int

target(struct sk_buff *skb,

       const struct net_device *in,

       const struct net_device *out,

       unsigned int hooknum,

       const struct xt_target *target,

       const void *targinfo)

{

        struct nf_conn *ct;

        enum ip_conntrack_info ctinfo;

        __be32 new_ip, netmask;

        const struct nf_nat_multi_range_compat *mr = targinfo;

        struct nf_nat_range newrange;

        NF_CT_ASSERT(hooknum == NF_IP_PRE_ROUTING

                     || hooknum == NF_IP_POST_ROUTING

                     || hooknum == NF_IP_LOCAL_OUT);

        ct = nf_ct_get(skb, &ctinfo);

        netmask = ~(mr->range[0].min_ip ^ mr->range[0].max_ip);

        if (hooknum == NF_IP_PRE_ROUTING || hooknum == NF_IP_LOCAL_OUT)

                new_ip = ip_hdr(skb)->daddr & ~netmask;

        else

                new_ip = ip_hdr(skb)->saddr & ~netmask;

        new_ip |= mr->range[0].min_ip & netmask;

        newrange = ((struct nf_nat_range)

                { mr->range[0].flags | IP_NAT_RANGE_MAP_IPS,

                  new_ip, new_ip,

                  mr->range[0].min, mr->range[0].max });

        /* Hand modified range to generic setup. */

        return nf_nat_setup_info(ct, &newrange, hooknum);

}

static struct xt_target target_module __read_mostly = {

        .name           = "NETMAP",

        .family         = AF_INET,

        .target         = target,

        .targetsize     = sizeof(struct nf_nat_multi_range_compat),

        .table          = "nat",

        .hooks          = (1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_POST_ROUTING) |

                          (1 << NF_IP_LOCAL_OUT),

        .checkentry     = check,

        .me             = THIS_MODULE

};

static int __init ipt_netmap_init(void)

{

        return xt_register_target(&target_module);

}

static void __exit ipt_netmap_fini(void)

{

        xt_unregister_target(&target_module);

}

module_init(ipt_netmap_init);

module_exit(ipt_netmap_fini);