/*
 * Copyright (c) 2014 Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
 *
 * 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/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_nat.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nft_redir.h>

const struct nla_policy nft_redir_policy[NFTA_REDIR_MAX + 1] = {
	[NFTA_REDIR_REG_PROTO_MIN]	= { .type = NLA_U32 },
	[NFTA_REDIR_REG_PROTO_MAX]	= { .type = NLA_U32 },
	[NFTA_REDIR_FLAGS]		= { .type = NLA_U32 },
};
EXPORT_SYMBOL_GPL(nft_redir_policy);

int nft_redir_validate(const struct nft_ctx *ctx,
		       const struct nft_expr *expr,
		       const struct nft_data **data)
{
	int err;

	err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
	if (err < 0)
		return err;

	return nft_chain_validate_hooks(ctx->chain,
					(1 << NF_INET_PRE_ROUTING) |
					(1 << NF_INET_LOCAL_OUT));
}
EXPORT_SYMBOL_GPL(nft_redir_validate);

int nft_redir_init(const struct nft_ctx *ctx,
		   const struct nft_expr *expr,
		   const struct nlattr * const tb[])
{
	struct nft_redir *priv = nft_expr_priv(expr);
	unsigned int plen;
	int err;

	err = nft_redir_validate(ctx, expr, NULL);
	if (err < 0)
		return err;

	plen = FIELD_SIZEOF(struct nf_nat_range, min_addr.all);
	if (tb[NFTA_REDIR_REG_PROTO_MIN]) {
		priv->sreg_proto_min =
			nft_parse_register(tb[NFTA_REDIR_REG_PROTO_MIN]);

		err = nft_validate_register_load(priv->sreg_proto_min, plen);
		if (err < 0)
			return err;

		if (tb[NFTA_REDIR_REG_PROTO_MAX]) {
			priv->sreg_proto_max =
				nft_parse_register(tb[NFTA_REDIR_REG_PROTO_MAX]);

			err = nft_validate_register_load(priv->sreg_proto_max,
							 plen);
			if (err < 0)
				return err;
		} else {
			priv->sreg_proto_max = priv->sreg_proto_min;
		}
	}

	if (tb[NFTA_REDIR_FLAGS]) {
		priv->flags = ntohl(nla_get_be32(tb[NFTA_REDIR_FLAGS]));
		if (priv->flags & ~NF_NAT_RANGE_MASK)
			return -EINVAL;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(nft_redir_init);

int nft_redir_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
	const struct nft_redir *priv = nft_expr_priv(expr);

	if (priv->sreg_proto_min) {
		if (nft_dump_register(skb, NFTA_REDIR_REG_PROTO_MIN,
				      priv->sreg_proto_min))
			goto nla_put_failure;
		if (nft_dump_register(skb, NFTA_REDIR_REG_PROTO_MAX,
				      priv->sreg_proto_max))
			goto nla_put_failure;
	}

	if (priv->flags != 0 &&
	    nla_put_be32(skb, NFTA_REDIR_FLAGS, htonl(priv->flags)))
			goto nla_put_failure;

	return 0;

nla_put_failure:
	return -1;
}
EXPORT_SYMBOL_GPL(nft_redir_dump);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>");