// SPDX-License-Identifier: GPL-2.0-only
/*
 * 'raw' table, which is the very first hooked in at PRE_ROUTING and LOCAL_OUT .
 *
 * Copyright (C) 2003 Jozsef Kadlecsik <kadlec@netfilter.org>
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/slab.h>
#include <net/ip.h>

#define RAW_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT))

static bool raw_before_defrag __read_mostly;
MODULE_PARM_DESC(raw_before_defrag, "Enable raw table before defrag");
module_param(raw_before_defrag, bool, 0000);

static const struct xt_table packet_raw = {
        .name = "raw",
        .valid_hooks =  RAW_VALID_HOOKS,
        .me = THIS_MODULE,
        .af = NFPROTO_IPV4,
        .priority = NF_IP_PRI_RAW,
};

static const struct xt_table packet_raw_before_defrag = {
        .name = "raw",
        .valid_hooks =  RAW_VALID_HOOKS,
        .me = THIS_MODULE,
        .af = NFPROTO_IPV4,
        .priority = NF_IP_PRI_RAW_BEFORE_DEFRAG,
};

static struct nf_hook_ops *rawtable_ops __read_mostly;

static int iptable_raw_table_init(struct net *net)
{
        struct ipt_replace *repl;
        const struct xt_table *table = &packet_raw;
        int ret;

        if (raw_before_defrag)
                table = &packet_raw_before_defrag;

        repl = ipt_alloc_initial_table(table);
        if (repl == NULL)
                return -ENOMEM;
        ret = ipt_register_table(net, table, repl, rawtable_ops);
        kfree(repl);
        return ret;
}

static void __net_exit iptable_raw_net_pre_exit(struct net *net)
{
        ipt_unregister_table_pre_exit(net, "raw");
}

static void __net_exit iptable_raw_net_exit(struct net *net)
{
        ipt_unregister_table_exit(net, "raw");
}

static struct pernet_operations iptable_raw_net_ops = {
        .pre_exit = iptable_raw_net_pre_exit,
        .exit = iptable_raw_net_exit,
};

static int __init iptable_raw_init(void)
{
        int ret;
        const struct xt_table *table = &packet_raw;

        if (raw_before_defrag) {
                table = &packet_raw_before_defrag;

                pr_info("Enabling raw table before defrag\n");
        }

        ret = xt_register_template(table,
                                   iptable_raw_table_init);
        if (ret < 0)
                return ret;

        rawtable_ops = xt_hook_ops_alloc(table, ipt_do_table);
        if (IS_ERR(rawtable_ops)) {
                xt_unregister_template(table);
                return PTR_ERR(rawtable_ops);
        }

        ret = register_pernet_subsys(&iptable_raw_net_ops);
        if (ret < 0) {
                xt_unregister_template(table);
                kfree(rawtable_ops);
                return ret;
        }

        return ret;
}

static void __exit iptable_raw_fini(void)
{
        unregister_pernet_subsys(&iptable_raw_net_ops);
        kfree(rawtable_ops);
        xt_unregister_template(&packet_raw);
}

module_init(iptable_raw_init);
module_exit(iptable_raw_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("iptables legacy raw table");