nf_defrag_ipv6_hooks.c

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/* (C) 1999-2001 Paul `Rusty' Russell
 * (C) 2002-2004 Netfilter Core Team <[email protected]>
 *
 * 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/types.h>
#include <linux/ipv6.h>
#include <linux/in6.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/icmp.h>
#include <linux/sysctl.h>
#include <net/ipv6.h>
#include <net/inet_frag.h>

#include <linux/netfilter_ipv6.h>
#include <linux/netfilter_bridge.h>
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
#endif
#include <net/netfilter/nf_conntrack_zones.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>

static enum ip6_defrag_users nf_ct6_defrag_user(unsigned int hooknum,
                        struct sk_buff *skb)
{
    u16 zone = NF_CT_DEFAULT_ZONE;

#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
    if (skb->nfct)
        zone = nf_ct_zone((struct nf_conn *)skb->nfct);
#endif

#ifdef CONFIG_BRIDGE_NETFILTER
    if (skb->nf_bridge &&
        skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)
        return IP6_DEFRAG_CONNTRACK_BRIDGE_IN + zone;
#endif
    if (hooknum == NF_INET_PRE_ROUTING)
        return IP6_DEFRAG_CONNTRACK_IN + zone;
    else
        return IP6_DEFRAG_CONNTRACK_OUT + zone;

}

static unsigned int ipv6_defrag(unsigned int hooknum,
                struct sk_buff *skb,
                const struct net_device *in,
                const struct net_device *out,
                int (*okfn)(struct sk_buff *))
{
    struct sk_buff *reasm;

#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
    /* Previously seen (loopback)?  */
    if (skb->nfct && !nf_ct_is_template((struct nf_conn *)skb->nfct))
        return NF_ACCEPT;
#endif

    reasm = nf_ct_frag6_gather(skb, nf_ct6_defrag_user(hooknum, skb));
    /* queued */
    if (reasm == NULL)
        return NF_STOLEN;

    /* error occurred or not fragmented */
    if (reasm == skb)
        return NF_ACCEPT;

    nf_ct_frag6_output(hooknum, reasm, (struct net_device *)in,
               (struct net_device *)out, okfn);

    return NF_STOLEN;
}

static struct nf_hook_ops ipv6_defrag_ops[] = {
    {
        .hook       = ipv6_defrag,
        .owner      = THIS_MODULE,
        .pf     = NFPROTO_IPV6,
        .hooknum    = NF_INET_PRE_ROUTING,
        .priority   = NF_IP6_PRI_CONNTRACK_DEFRAG,
    },
    {
        .hook       = ipv6_defrag,
        .owner      = THIS_MODULE,
        .pf     = NFPROTO_IPV6,
        .hooknum    = NF_INET_LOCAL_OUT,
        .priority   = NF_IP6_PRI_CONNTRACK_DEFRAG,
    },
};

static int __init nf_defrag_init(void)
{
    int ret = 0;

    ret = nf_ct_frag6_init();
    if (ret < 0) {
        pr_err("nf_defrag_ipv6: can't initialize frag6.\n");
        return ret;
    }
    ret = nf_register_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
    if (ret < 0) {
        pr_err("nf_defrag_ipv6: can't register hooks\n");
        goto cleanup_frag6;
    }
    return ret;

cleanup_frag6:
    nf_ct_frag6_cleanup();
    return ret;

}

static void __exit nf_defrag_fini(void)
{
    nf_unregister_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
    nf_ct_frag6_cleanup();
}

void nf_defrag_ipv6_enable(void)
{
}
EXPORT_SYMBOL_GPL(nf_defrag_ipv6_enable);

module_init(nf_defrag_init);
module_exit(nf_defrag_fini);

MODULE_LICENSE("GPL");