root/net/ipv6/netfilter/ip6table_filter.c

DEFINITIONS

1. ip6t_local_in_hook
2. ip6t_forward_hook
3. ip6t_local_out_hook
4. ip6table_filter_net_init
5. ip6table_filter_net_exit
6. ip6table_filter_init
7. ip6table_filter_fini

/*
 * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
 *
 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
 * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
 *
 * 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/moduleparam.h>
#include <linux/netfilter_ipv6/ip6_tables.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("ip6tables filter table");

#define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
                            (1 << NF_INET_FORWARD) | \
                            (1 << NF_INET_LOCAL_OUT))

static struct
{
        struct ip6t_replace repl;
        struct ip6t_standard entries[3];
        struct ip6t_error term;
} initial_table __net_initdata = {
        .repl = {
                .name = "filter",
                .valid_hooks = FILTER_VALID_HOOKS,
                .num_entries = 4,
                .size = sizeof(struct ip6t_standard) * 3 + sizeof(struct ip6t_error),
                .hook_entry = {
                        [NF_INET_LOCAL_IN] = 0,
                        [NF_INET_FORWARD] = sizeof(struct ip6t_standard),
                        [NF_INET_LOCAL_OUT] = sizeof(struct ip6t_standard) * 2
                },
                .underflow = {
                        [NF_INET_LOCAL_IN] = 0,
                        [NF_INET_FORWARD] = sizeof(struct ip6t_standard),
                        [NF_INET_LOCAL_OUT] = sizeof(struct ip6t_standard) * 2
                },
        },
        .entries = {
                IP6T_STANDARD_INIT(NF_ACCEPT),  /* LOCAL_IN */
                IP6T_STANDARD_INIT(NF_ACCEPT),  /* FORWARD */
                IP6T_STANDARD_INIT(NF_ACCEPT),  /* LOCAL_OUT */
        },
        .term = IP6T_ERROR_INIT,                /* ERROR */
};

static struct xt_table packet_filter = {
        .name           = "filter",
        .valid_hooks    = FILTER_VALID_HOOKS,
        .lock           = __RW_LOCK_UNLOCKED(packet_filter.lock),
        .me             = THIS_MODULE,
        .af             = AF_INET6,
};

/* The work comes in here from netfilter.c. */
static unsigned int
ip6t_local_in_hook(unsigned int hook,
                   struct sk_buff *skb,
                   const struct net_device *in,
                   const struct net_device *out,
                   int (*okfn)(struct sk_buff *))
{
        return ip6t_do_table(skb, hook, in, out,
                             dev_net(in)->ipv6.ip6table_filter);
}

static unsigned int
ip6t_forward_hook(unsigned int hook,
                  struct sk_buff *skb,
                  const struct net_device *in,
                  const struct net_device *out,
                  int (*okfn)(struct sk_buff *))
{
        return ip6t_do_table(skb, hook, in, out,
                             dev_net(in)->ipv6.ip6table_filter);
}

static unsigned int
ip6t_local_out_hook(unsigned int hook,
                   struct sk_buff *skb,
                   const struct net_device *in,
                   const struct net_device *out,
                   int (*okfn)(struct sk_buff *))
{
#if 0
        /* root is playing with raw sockets. */
        if (skb->len < sizeof(struct iphdr)
            || ip_hdrlen(skb) < sizeof(struct iphdr)) {
                if (net_ratelimit())
                        printk("ip6t_hook: happy cracking.\n");
                return NF_ACCEPT;
        }
#endif

        return ip6t_do_table(skb, hook, in, out,
                             dev_net(out)->ipv6.ip6table_filter);
}

static struct nf_hook_ops ip6t_ops[] __read_mostly = {
        {
                .hook           = ip6t_local_in_hook,
                .owner          = THIS_MODULE,
                .pf             = PF_INET6,
                .hooknum        = NF_INET_LOCAL_IN,
                .priority       = NF_IP6_PRI_FILTER,
        },
        {
                .hook           = ip6t_forward_hook,
                .owner          = THIS_MODULE,
                .pf             = PF_INET6,
                .hooknum        = NF_INET_FORWARD,
                .priority       = NF_IP6_PRI_FILTER,
        },
        {
                .hook           = ip6t_local_out_hook,
                .owner          = THIS_MODULE,
                .pf             = PF_INET6,
                .hooknum        = NF_INET_LOCAL_OUT,
                .priority       = NF_IP6_PRI_FILTER,
        },
};

/* Default to forward because I got too much mail already. */
static int forward = NF_ACCEPT;
module_param(forward, bool, 0000);

static int __net_init ip6table_filter_net_init(struct net *net)
{
        /* Register table */
        net->ipv6.ip6table_filter =
                ip6t_register_table(net, &packet_filter, &initial_table.repl);
        if (IS_ERR(net->ipv6.ip6table_filter))
                return PTR_ERR(net->ipv6.ip6table_filter);
        return 0;
}

static void __net_exit ip6table_filter_net_exit(struct net *net)
{
        ip6t_unregister_table(net->ipv6.ip6table_filter);
}

static struct pernet_operations ip6table_filter_net_ops = {
        .init = ip6table_filter_net_init,
        .exit = ip6table_filter_net_exit,
};

static int __init ip6table_filter_init(void)
{
        int ret;

        if (forward < 0 || forward > NF_MAX_VERDICT) {
                printk("iptables forward must be 0 or 1\n");
                return -EINVAL;
        }

        /* Entry 1 is the FORWARD hook */
        initial_table.entries[1].target.verdict = -forward - 1;

        ret = register_pernet_subsys(&ip6table_filter_net_ops);
        if (ret < 0)
                return ret;

        /* Register hooks */
        ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
        if (ret < 0)
                goto cleanup_table;

        return ret;

 cleanup_table:
        unregister_pernet_subsys(&ip6table_filter_net_ops);
        return ret;
}

static void __exit ip6table_filter_fini(void)
{
        nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
        unregister_pernet_subsys(&ip6table_filter_net_ops);
}

module_init(ip6table_filter_init);
module_exit(ip6table_filter_fini);