// SPDX-License-Identifier: GPL-2.0-only
/*
 *  ebt_mark
 *
 *      Authors:
 *      Bart De Schuymer <bdschuym@pandora.be>
 *
 *  July, 2002
 *
 */

/* The mark target can be used in any chain,
 * I believe adding a mangle table just for marking is total overkill.
 * Marking a frame doesn't really change anything in the frame anyway.
 */

#include <linux/module.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_mark_t.h>

static unsigned int
ebt_mark_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
        const struct ebt_mark_t_info *info = par->targinfo;
        int action = info->target & -16;

        if (action == MARK_SET_VALUE)
                skb->mark = info->mark;
        else if (action == MARK_OR_VALUE)
                skb->mark |= info->mark;
        else if (action == MARK_AND_VALUE)
                skb->mark &= info->mark;
        else
                skb->mark ^= info->mark;

        return info->target | ~EBT_VERDICT_BITS;
}

static int ebt_mark_tg_check(const struct xt_tgchk_param *par)
{
        const struct ebt_mark_t_info *info = par->targinfo;
        int tmp;

        tmp = info->target | ~EBT_VERDICT_BITS;
        if (BASE_CHAIN && tmp == EBT_RETURN)
                return -EINVAL;
        if (ebt_invalid_target(tmp))
                return -EINVAL;
        tmp = info->target & ~EBT_VERDICT_BITS;
        if (tmp != MARK_SET_VALUE && tmp != MARK_OR_VALUE &&
            tmp != MARK_AND_VALUE && tmp != MARK_XOR_VALUE)
                return -EINVAL;
        return 0;
}
#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
struct compat_ebt_mark_t_info {
        compat_ulong_t mark;
        compat_uint_t target;
};

static void mark_tg_compat_from_user(void *dst, const void *src)
{
        const struct compat_ebt_mark_t_info *user = src;
        struct ebt_mark_t_info *kern = dst;

        kern->mark = user->mark;
        kern->target = user->target;
}

static int mark_tg_compat_to_user(void __user *dst, const void *src)
{
        struct compat_ebt_mark_t_info __user *user = dst;
        const struct ebt_mark_t_info *kern = src;

        if (put_user(kern->mark, &user->mark) ||
            put_user(kern->target, &user->target))
                return -EFAULT;
        return 0;
}
#endif

static struct xt_target ebt_mark_tg_reg __read_mostly = {
        .name           = "mark",
        .revision       = 0,
        .family         = NFPROTO_BRIDGE,
        .target         = ebt_mark_tg,
        .checkentry     = ebt_mark_tg_check,
        .targetsize     = sizeof(struct ebt_mark_t_info),
#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
        .compatsize     = sizeof(struct compat_ebt_mark_t_info),
        .compat_from_user = mark_tg_compat_from_user,
        .compat_to_user = mark_tg_compat_to_user,
#endif
        .me             = THIS_MODULE,
};

static int __init ebt_mark_init(void)
{
        return xt_register_target(&ebt_mark_tg_reg);
}

static void __exit ebt_mark_fini(void)
{
        xt_unregister_target(&ebt_mark_tg_reg);
}

module_init(ebt_mark_init);
module_exit(ebt_mark_fini);
MODULE_DESCRIPTION("Ebtables: Packet mark modification");
MODULE_LICENSE("GPL");