/*
   * Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
   *
   * 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.
   *
   * Development of this code funded by Astaro AG (http://www.astaro.com/)
   */
  
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/list.h>
  #include <linux/rbtree.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_core.h>

  
  struct nft_lookup {
  	struct nft_set			*set;
  	enum nft_registers		sreg:8;
  	enum nft_registers		dreg:8;
  	struct nft_set_binding		binding;
  };
  
  static void nft_lookup_eval(const struct nft_expr *expr,
  			    struct nft_data data[NFT_REG_MAX + 1],
  			    const struct nft_pktinfo *pkt)
  {
  	const struct nft_lookup *priv = nft_expr_priv(expr);
  	const struct nft_set *set = priv->set;
  
  	if (set->ops->lookup(set, &data[priv->sreg], &data[priv->dreg]))
  		return;
  	data[NFT_REG_VERDICT].verdict = NFT_BREAK;
  }
  
  static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
  	[NFTA_LOOKUP_SET]	= { .type = NLA_STRING },
  	[NFTA_LOOKUP_SREG]	= { .type = NLA_U32 },
  	[NFTA_LOOKUP_DREG]	= { .type = NLA_U32 },
  };
  
  static int nft_lookup_init(const struct nft_ctx *ctx,
  			   const struct nft_expr *expr,
  			   const struct nlattr * const tb[])
  {
  	struct nft_lookup *priv = nft_expr_priv(expr);
  	struct nft_set *set;
  	int err;
  
  	if (tb[NFTA_LOOKUP_SET] == NULL ||
  	    tb[NFTA_LOOKUP_SREG] == NULL)
  		return -EINVAL;
  
  	set = nf_tables_set_lookup(ctx->table, tb[NFTA_LOOKUP_SET]);

  	if (IS_ERR(set)) {
  		if (tb[NFTA_LOOKUP_SET_ID]) {
  			set = nf_tables_set_lookup_byid(ctx->net,
  							tb[NFTA_LOOKUP_SET_ID]);
  		}
  		if (IS_ERR(set))
  			return PTR_ERR(set);
  	}

  
  	priv->sreg = ntohl(nla_get_be32(tb[NFTA_LOOKUP_SREG]));
  	err = nft_validate_input_register(priv->sreg);
  	if (err < 0)
  		return err;
  
  	if (tb[NFTA_LOOKUP_DREG] != NULL) {
  		if (!(set->flags & NFT_SET_MAP))
  			return -EINVAL;
  
  		priv->dreg = ntohl(nla_get_be32(tb[NFTA_LOOKUP_DREG]));
  		err = nft_validate_output_register(priv->dreg);
  		if (err < 0)
  			return err;
  
  		if (priv->dreg == NFT_REG_VERDICT) {
  			if (set->dtype != NFT_DATA_VERDICT)
  				return -EINVAL;
  		} else if (set->dtype == NFT_DATA_VERDICT)
  			return -EINVAL;
  	} else if (set->flags & NFT_SET_MAP)
  		return -EINVAL;
  
  	err = nf_tables_bind_set(ctx, set, &priv->binding);
  	if (err < 0)
  		return err;
  
  	priv->set = set;
  	return 0;
  }

  static void nft_lookup_destroy(const struct nft_ctx *ctx,
  			       const struct nft_expr *expr)

  {
  	struct nft_lookup *priv = nft_expr_priv(expr);

  	nf_tables_unbind_set(ctx, priv->set, &priv->binding);

  }
  
  static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
  {
  	const struct nft_lookup *priv = nft_expr_priv(expr);
  
  	if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
  		goto nla_put_failure;
  	if (nla_put_be32(skb, NFTA_LOOKUP_SREG, htonl(priv->sreg)))
  		goto nla_put_failure;
  	if (priv->set->flags & NFT_SET_MAP)
  		if (nla_put_be32(skb, NFTA_LOOKUP_DREG, htonl(priv->dreg)))
  			goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return -1;
  }

  static struct nft_expr_type nft_lookup_type;
  static const struct nft_expr_ops nft_lookup_ops = {
  	.type		= &nft_lookup_type,

  	.size		= NFT_EXPR_SIZE(sizeof(struct nft_lookup)),

  	.eval		= nft_lookup_eval,
  	.init		= nft_lookup_init,
  	.destroy	= nft_lookup_destroy,
  	.dump		= nft_lookup_dump,

  };
  
  static struct nft_expr_type nft_lookup_type __read_mostly = {
  	.name		= "lookup",
  	.ops		= &nft_lookup_ops,

  	.policy		= nft_lookup_policy,
  	.maxattr	= NFTA_LOOKUP_MAX,

  	.owner		= THIS_MODULE,

  };
  
  int __init nft_lookup_module_init(void)
  {

  	return nft_register_expr(&nft_lookup_type);

  }
  
  void nft_lookup_module_exit(void)
  {

  	nft_unregister_expr(&nft_lookup_type);

  }