text: /*
   * Copyright (c) 2012-2016 Pablo Neira Ayuso <pablo@netfilter.org>
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   */
  
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/skbuff.h>
  #include <linux/netlink.h>
  #include <linux/netfilter.h>
  #include <linux/netfilter/nf_tables.h>
  #include <net/netfilter/nf_tables.h>
  
  #define nft_objref_priv(expr)	*((struct nft_object **)nft_expr_priv(expr))
  
  static void nft_objref_eval(const struct nft_expr *expr,
  			    struct nft_regs *regs,
  			    const struct nft_pktinfo *pkt)
  {
  	struct nft_object *obj = nft_objref_priv(expr);
  
  	obj->ops->eval(obj, regs, pkt);
  }
  
  static int nft_objref_init(const struct nft_ctx *ctx,
  			   const struct nft_expr *expr,
  			   const struct nlattr * const tb[])
  {
  	struct nft_object *obj = nft_objref_priv(expr);
  	u8 genmask = nft_genmask_next(ctx->net);
  	u32 objtype;
  
  	if (!tb[NFTA_OBJREF_IMM_NAME] ||
  	    !tb[NFTA_OBJREF_IMM_TYPE])
  		return -EINVAL;
  
  	objtype = ntohl(nla_get_be32(tb[NFTA_OBJREF_IMM_TYPE]));
  	obj = nft_obj_lookup(ctx->table, tb[NFTA_OBJREF_IMM_NAME], objtype,
  			     genmask);
  	if (IS_ERR(obj))
  		return -ENOENT;
  
  	nft_objref_priv(expr) = obj;
  	obj->use++;
  
  	return 0;
  }
  
  static int nft_objref_dump(struct sk_buff *skb, const struct nft_expr *expr)
  {
  	const struct nft_object *obj = nft_objref_priv(expr);
  
  	if (nla_put_string(skb, NFTA_OBJREF_IMM_NAME, obj->name) ||
  	    nla_put_be32(skb, NFTA_OBJREF_IMM_TYPE,
  			 htonl(obj->ops->type->type)))
  		goto nla_put_failure;
  
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static void nft_objref_destroy(const struct nft_ctx *ctx,
  			       const struct nft_expr *expr)
  {
  	struct nft_object *obj = nft_objref_priv(expr);
  
  	obj->use--;
  }
  
  static struct nft_expr_type nft_objref_type;
  static const struct nft_expr_ops nft_objref_ops = {
  	.type		= &nft_objref_type,
  	.size		= NFT_EXPR_SIZE(sizeof(struct nft_object *)),
  	.eval		= nft_objref_eval,
  	.init		= nft_objref_init,
  	.destroy	= nft_objref_destroy,
  	.dump		= nft_objref_dump,
  };
  
  struct nft_objref_map {
  	struct nft_set		*set;
  	enum nft_registers	sreg:8;
  	struct nft_set_binding	binding;
  };
  
  static void nft_objref_map_eval(const struct nft_expr *expr,
  				struct nft_regs *regs,
  				const struct nft_pktinfo *pkt)
  {
  	struct nft_objref_map *priv = nft_expr_priv(expr);
  	const struct nft_set *set = priv->set;
  	const struct nft_set_ext *ext;
  	struct nft_object *obj;
  	bool found;
  
  	found = set->ops->lookup(nft_net(pkt), set, &regs->data[priv->sreg],
  				 &ext);
  	if (!found) {
  		regs->verdict.code = NFT_BREAK;
  		return;
  	}
  	obj = *nft_set_ext_obj(ext);
  	obj->ops->eval(obj, regs, pkt);
  }
  
  static int nft_objref_map_init(const struct nft_ctx *ctx,
  			       const struct nft_expr *expr,
  			       const struct nlattr * const tb[])
  {
  	struct nft_objref_map *priv = nft_expr_priv(expr);
  	u8 genmask = nft_genmask_next(ctx->net);
  	struct nft_set *set;
  	int err;
  
  	set = nft_set_lookup_global(ctx->net, ctx->table,
  				    tb[NFTA_OBJREF_SET_NAME],
  				    tb[NFTA_OBJREF_SET_ID], genmask);
  	if (IS_ERR(set))
  		return PTR_ERR(set);
  
  	if (!(set->flags & NFT_SET_OBJECT))
  		return -EINVAL;
  
  	priv->sreg = nft_parse_register(tb[NFTA_OBJREF_SET_SREG]);
  	err = nft_validate_register_load(priv->sreg, set->klen);
  	if (err < 0)
  		return err;
  
  	priv->binding.flags = set->flags & NFT_SET_OBJECT;
  
  	err = nf_tables_bind_set(ctx, set, &priv->binding);
  	if (err < 0)
  		return err;
  
  	priv->set = set;
  	return 0;
  }
  
  static int nft_objref_map_dump(struct sk_buff *skb, const struct nft_expr *expr)
  {
  	const struct nft_objref_map *priv = nft_expr_priv(expr);
  
  	if (nft_dump_register(skb, NFTA_OBJREF_SET_SREG, priv->sreg) ||
  	    nla_put_string(skb, NFTA_OBJREF_SET_NAME, priv->set->name))
  		goto nla_put_failure;
  
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static void nft_objref_map_destroy(const struct nft_ctx *ctx,
  				   const struct nft_expr *expr)
  {
  	struct nft_objref_map *priv = nft_expr_priv(expr);
  
  	nf_tables_unbind_set(ctx, priv->set, &priv->binding);
  }
  
  static struct nft_expr_type nft_objref_type;
  static const struct nft_expr_ops nft_objref_map_ops = {
  	.type		= &nft_objref_type,
  	.size		= NFT_EXPR_SIZE(sizeof(struct nft_objref_map)),
  	.eval		= nft_objref_map_eval,
  	.init		= nft_objref_map_init,
  	.destroy	= nft_objref_map_destroy,
  	.dump		= nft_objref_map_dump,
  };
  
  static const struct nft_expr_ops *
  nft_objref_select_ops(const struct nft_ctx *ctx,
                        const struct nlattr * const tb[])
  {
  	if (tb[NFTA_OBJREF_SET_SREG] &&
  	    (tb[NFTA_OBJREF_SET_NAME] ||
  	     tb[NFTA_OBJREF_SET_ID]))
  		return &nft_objref_map_ops;
  	else if (tb[NFTA_OBJREF_IMM_NAME] &&
  		 tb[NFTA_OBJREF_IMM_TYPE])
  		return &nft_objref_ops;
  
  	return ERR_PTR(-EOPNOTSUPP);
  }
  
  static const struct nla_policy nft_objref_policy[NFTA_OBJREF_MAX + 1] = {
  	[NFTA_OBJREF_IMM_NAME]	= { .type = NLA_STRING,
  				    .len = NFT_OBJ_MAXNAMELEN - 1 },
  	[NFTA_OBJREF_IMM_TYPE]	= { .type = NLA_U32 },
  	[NFTA_OBJREF_SET_SREG]	= { .type = NLA_U32 },
  	[NFTA_OBJREF_SET_NAME]	= { .type = NLA_STRING,
  				    .len = NFT_SET_MAXNAMELEN - 1 },
  	[NFTA_OBJREF_SET_ID]	= { .type = NLA_U32 },
  };
  
  static struct nft_expr_type nft_objref_type __read_mostly = {
  	.name		= "objref",
  	.select_ops	= nft_objref_select_ops,
  	.policy		= nft_objref_policy,
  	.maxattr	= NFTA_OBJREF_MAX,
  	.owner		= THIS_MODULE,
  };
  
  static int __init nft_objref_module_init(void)
  {
  	return nft_register_expr(&nft_objref_type);
  }
  
  static void __exit nft_objref_module_exit(void)
  {
  	nft_unregister_expr(&nft_objref_type);
  }
  
  module_init(nft_objref_module_init);
  module_exit(nft_objref_module_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
  MODULE_ALIAS_NFT_EXPR("objref");
  