/*

   * Copyright (c) 2014 Arturo Borrero Gonzalez <arturo@debian.org>

   *
   * 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_tables.h>
  #include <net/netfilter/nf_nat.h>
  #include <net/netfilter/nft_masq.h>
  
  const struct nla_policy nft_masq_policy[NFTA_MASQ_MAX + 1] = {

  	[NFTA_MASQ_FLAGS]		= { .type = NLA_U32 },
  	[NFTA_MASQ_REG_PROTO_MIN]	= { .type = NLA_U32 },
  	[NFTA_MASQ_REG_PROTO_MAX]	= { .type = NLA_U32 },

  };
  EXPORT_SYMBOL_GPL(nft_masq_policy);

  int nft_masq_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_POST_ROUTING));
  }
  EXPORT_SYMBOL_GPL(nft_masq_validate);

  int nft_masq_init(const struct nft_ctx *ctx,
  		  const struct nft_expr *expr,
  		  const struct nlattr * const tb[])
  {

  	u32 plen = FIELD_SIZEOF(struct nf_nat_range, min_addr.all);

  	struct nft_masq *priv = nft_expr_priv(expr);

  	int err;

  	if (tb[NFTA_MASQ_FLAGS]) {
  		priv->flags = ntohl(nla_get_be32(tb[NFTA_MASQ_FLAGS]));
  		if (priv->flags & ~NF_NAT_RANGE_MASK)
  			return -EINVAL;
  	}
  
  	if (tb[NFTA_MASQ_REG_PROTO_MIN]) {
  		priv->sreg_proto_min =
  			nft_parse_register(tb[NFTA_MASQ_REG_PROTO_MIN]);
  
  		err = nft_validate_register_load(priv->sreg_proto_min, plen);
  		if (err < 0)
  			return err;
  
  		if (tb[NFTA_MASQ_REG_PROTO_MAX]) {
  			priv->sreg_proto_max =
  				nft_parse_register(tb[NFTA_MASQ_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;
  		}
  	}

  	return nf_ct_netns_get(ctx->net, ctx->afi->family);

  }
  EXPORT_SYMBOL_GPL(nft_masq_init);
  
  int nft_masq_dump(struct sk_buff *skb, const struct nft_expr *expr)
  {
  	const struct nft_masq *priv = nft_expr_priv(expr);

  	if (priv->flags != 0 &&
  	    nla_put_be32(skb, NFTA_MASQ_FLAGS, htonl(priv->flags)))

  		goto nla_put_failure;

  	if (priv->sreg_proto_min) {
  		if (nft_dump_register(skb, NFTA_MASQ_REG_PROTO_MIN,
  				      priv->sreg_proto_min) ||
  		    nft_dump_register(skb, NFTA_MASQ_REG_PROTO_MAX,
  				      priv->sreg_proto_max))
  			goto nla_put_failure;
  	}

  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  EXPORT_SYMBOL_GPL(nft_masq_dump);
  
  MODULE_LICENSE("GPL");

  MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo@debian.org>");