// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_offload.h>
#include <net/netfilter/nf_dup_netdev.h>

struct nft_dup_netdev {
        u8      sreg_dev;
};

static void nft_dup_netdev_eval(const struct nft_expr *expr,
                                struct nft_regs *regs,
                                const struct nft_pktinfo *pkt)
{
        struct nft_dup_netdev *priv = nft_expr_priv(expr);
        int oif = regs->data[priv->sreg_dev];

        nf_dup_netdev_egress(pkt, oif);
}

static const struct nla_policy nft_dup_netdev_policy[NFTA_DUP_MAX + 1] = {
        [NFTA_DUP_SREG_DEV]     = { .type = NLA_U32 },
};

static int nft_dup_netdev_init(const struct nft_ctx *ctx,
                               const struct nft_expr *expr,
                               const struct nlattr * const tb[])
{
        struct nft_dup_netdev *priv = nft_expr_priv(expr);

        if (tb[NFTA_DUP_SREG_DEV] == NULL)
                return -EINVAL;

        return nft_parse_register_load(ctx, tb[NFTA_DUP_SREG_DEV], &priv->sreg_dev,
                                       sizeof(int));
}

static int nft_dup_netdev_dump(struct sk_buff *skb,
                               const struct nft_expr *expr, bool reset)
{
        struct nft_dup_netdev *priv = nft_expr_priv(expr);

        if (nft_dump_register(skb, NFTA_DUP_SREG_DEV, priv->sreg_dev))
                goto nla_put_failure;

        return 0;

nla_put_failure:
        return -1;
}

static int nft_dup_netdev_offload(struct nft_offload_ctx *ctx,
                                  struct nft_flow_rule *flow,
                                  const struct nft_expr *expr)
{
        const struct nft_dup_netdev *priv = nft_expr_priv(expr);
        int oif = ctx->regs[priv->sreg_dev].data.data[0];

        return nft_fwd_dup_netdev_offload(ctx, flow, FLOW_ACTION_MIRRED, oif);
}

static bool nft_dup_netdev_offload_action(const struct nft_expr *expr)
{
        return true;
}

static struct nft_expr_type nft_dup_netdev_type;
static const struct nft_expr_ops nft_dup_netdev_ops = {
        .type           = &nft_dup_netdev_type,
        .size           = NFT_EXPR_SIZE(sizeof(struct nft_dup_netdev)),
        .eval           = nft_dup_netdev_eval,
        .init           = nft_dup_netdev_init,
        .dump           = nft_dup_netdev_dump,
        .reduce         = NFT_REDUCE_READONLY,
        .offload        = nft_dup_netdev_offload,
        .offload_action = nft_dup_netdev_offload_action,
};

static struct nft_expr_type nft_dup_netdev_type __read_mostly = {
        .family         = NFPROTO_NETDEV,
        .name           = "dup",
        .ops            = &nft_dup_netdev_ops,
        .policy         = nft_dup_netdev_policy,
        .maxattr        = NFTA_DUP_MAX,
        .owner          = THIS_MODULE,
};

static int __init nft_dup_netdev_module_init(void)
{
        return nft_register_expr(&nft_dup_netdev_type);
}

static void __exit nft_dup_netdev_module_exit(void)
{
        nft_unregister_expr(&nft_dup_netdev_type);
}

module_init(nft_dup_netdev_module_init);
module_exit(nft_dup_netdev_module_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_ALIAS_NFT_AF_EXPR(5, "dup");
MODULE_DESCRIPTION("nftables netdev packet duplication support");