net/netfilter/nft_dynset.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2015 Patrick McHardy <kaber@trash.net>
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.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_dynset {
 	struct nft_set			*set;
 	struct nft_set_ext_tmpl		tmpl;
 	enum nft_dynset_ops		op:8;
 	u8				sreg_key;
 	u8				sreg_data;
 	bool				invert;
 	bool				expr;
 	u8				num_exprs;
 	u64				timeout;
 	struct nft_expr			*expr_array[NFT_SET_EXPR_MAX];
 	struct nft_set_binding		binding;
 };

 static int nft_dynset_expr_setup(const struct nft_dynset *priv,
 				 const struct nft_set_ext *ext)
 {
 	struct nft_set_elem_expr *elem_expr = nft_set_ext_expr(ext);
 	struct nft_expr *expr;
 	int i;

 	for (i = 0; i < priv->num_exprs; i++) {
 		expr = nft_setelem_expr_at(elem_expr, elem_expr->size);
 		if (nft_expr_clone(expr, priv->expr_array[i]) < 0)
 			return -1;

 		elem_expr->size += priv->expr_array[i]->ops->size;
 	}

 	return 0;
 }

 static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr,
 			    struct nft_regs *regs)
 {
 	const struct nft_dynset *priv = nft_expr_priv(expr);
 	struct nft_set_ext *ext;
 	u64 timeout;
 	void *elem;

 	if (!atomic_add_unless(&set->nelems, 1, set->size))
 		return NULL;

 	timeout = priv->timeout ? : set->timeout;
 	elem = nft_set_elem_init(set, &priv->tmpl,
 				 &regs->data[priv->sreg_key], NULL,
 				 &regs->data[priv->sreg_data],
 				 timeout, 0, GFP_ATOMIC);
 	if (elem == NULL)
 		goto err1;

 	ext = nft_set_elem_ext(set, elem);
 	if (priv->num_exprs && nft_dynset_expr_setup(priv, ext) < 0)
 		goto err2;

 	return elem;

 err2:
 	nft_set_elem_destroy(set, elem, false);
 err1:
 	if (set->size)
 		atomic_dec(&set->nelems);
 	return NULL;
 }

 void nft_dynset_eval(const struct nft_expr *expr,
 		     struct nft_regs *regs, const struct nft_pktinfo *pkt)
 {
 	const struct nft_dynset *priv = nft_expr_priv(expr);
 	struct nft_set *set = priv->set;
 	const struct nft_set_ext *ext;
 	u64 timeout;

 	if (priv->op == NFT_DYNSET_OP_DELETE) {
 		set->ops->delete(set, &regs->data[priv->sreg_key]);
 		return;
 	}

 	if (set->ops->update(set, &regs->data[priv->sreg_key], nft_dynset_new,
 			     expr, regs, &ext)) {
 		if (priv->op == NFT_DYNSET_OP_UPDATE &&
 		    nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
 			timeout = priv->timeout ? : set->timeout;
 			*nft_set_ext_expiration(ext) = get_jiffies_64() + timeout;
 		}

 		nft_set_elem_update_expr(ext, regs, pkt);

 		if (priv->invert)
 			regs->verdict.code = NFT_BREAK;
 		return;
 	}

 	if (!priv->invert)
 		regs->verdict.code = NFT_BREAK;
 }

 static void nft_dynset_ext_add_expr(struct nft_dynset *priv)
 {
 	u8 size = 0;
 	int i;

 	for (i = 0; i < priv->num_exprs; i++)
 		size += priv->expr_array[i]->ops->size;

 	nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPRESSIONS,
 			       sizeof(struct nft_set_elem_expr) + size);
 }

 static struct nft_expr *
 nft_dynset_expr_alloc(const struct nft_ctx *ctx, const struct nft_set *set,
 		      const struct nlattr *attr, int pos)
 {
 	struct nft_expr *expr;
 	int err;

 	expr = nft_set_elem_expr_alloc(ctx, set, attr);
 	if (IS_ERR(expr))
 		return expr;

 	if (set->exprs[pos] && set->exprs[pos]->ops != expr->ops) {
 		err = -EOPNOTSUPP;
 		goto err_dynset_expr;
 	}

 	return expr;

 err_dynset_expr:
 	nft_expr_destroy(ctx, expr);
 	return ERR_PTR(err);
 }

 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
 	[NFTA_DYNSET_SET_NAME]	= { .type = NLA_STRING,
 				    .len = NFT_SET_MAXNAMELEN - 1 },
 	[NFTA_DYNSET_SET_ID]	= { .type = NLA_U32 },
 	[NFTA_DYNSET_OP]	= { .type = NLA_U32 },
 	[NFTA_DYNSET_SREG_KEY]	= { .type = NLA_U32 },
 	[NFTA_DYNSET_SREG_DATA]	= { .type = NLA_U32 },
 	[NFTA_DYNSET_TIMEOUT]	= { .type = NLA_U64 },
 	[NFTA_DYNSET_EXPR]	= { .type = NLA_NESTED },
 	[NFTA_DYNSET_FLAGS]	= { .type = NLA_U32 },
 	[NFTA_DYNSET_EXPRESSIONS] = { .type = NLA_NESTED },
 };

 static int nft_dynset_init(const struct nft_ctx *ctx,
 			   const struct nft_expr *expr,
 			   const struct nlattr * const tb[])
 {
 	struct nft_dynset *priv = nft_expr_priv(expr);
 	u8 genmask = nft_genmask_next(ctx->net);
 	struct nft_set *set;
 	u64 timeout;
 	int err, i;

 	lockdep_assert_held(&ctx->net->nft.commit_mutex);

 	if (tb[NFTA_DYNSET_SET_NAME] == NULL ||
 	    tb[NFTA_DYNSET_OP] == NULL ||
 	    tb[NFTA_DYNSET_SREG_KEY] == NULL)
 		return -EINVAL;

 	if (tb[NFTA_DYNSET_FLAGS]) {
 		u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS]));
 		if (flags & ~(NFT_DYNSET_F_INV | NFT_DYNSET_F_EXPR))
 			return -EOPNOTSUPP;
 		if (flags & NFT_DYNSET_F_INV)
 			priv->invert = true;
 		if (flags & NFT_DYNSET_F_EXPR)
 			priv->expr = true;
 	}

 	set = nft_set_lookup_global(ctx->net, ctx->table,
 				    tb[NFTA_DYNSET_SET_NAME],
 				    tb[NFTA_DYNSET_SET_ID], genmask);
 	if (IS_ERR(set))
 		return PTR_ERR(set);

 	if (set->ops->update == NULL)
 		return -EOPNOTSUPP;

 	if (set->flags & NFT_SET_CONSTANT)
 		return -EBUSY;

 	priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
 	switch (priv->op) {
 	case NFT_DYNSET_OP_ADD:
 	case NFT_DYNSET_OP_DELETE:
 		break;
 	case NFT_DYNSET_OP_UPDATE:
 		if (!(set->flags & NFT_SET_TIMEOUT))
 			return -EOPNOTSUPP;
 		break;
 	default:
 		return -EOPNOTSUPP;
 	}

 	timeout = 0;
 	if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
 		if (!(set->flags & NFT_SET_TIMEOUT))
 			return -EOPNOTSUPP;

 		err = nf_msecs_to_jiffies64(tb[NFTA_DYNSET_TIMEOUT], &timeout);
 		if (err)
 			return err;
 	}

 	err = nft_parse_register_load(tb[NFTA_DYNSET_SREG_KEY], &priv->sreg_key,
 				      set->klen);
 	if (err < 0)
 		return err;

 	if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
 		if (!(set->flags & NFT_SET_MAP))
 			return -EOPNOTSUPP;
 		if (set->dtype == NFT_DATA_VERDICT)
 			return -EOPNOTSUPP;

 		err = nft_parse_register_load(tb[NFTA_DYNSET_SREG_DATA],
 					      &priv->sreg_data, set->dlen);
 		if (err < 0)
 			return err;
 	} else if (set->flags & NFT_SET_MAP)
 		return -EINVAL;

 	if ((tb[NFTA_DYNSET_EXPR] || tb[NFTA_DYNSET_EXPRESSIONS]) &&
 	    !(set->flags & NFT_SET_EVAL))
 		return -EINVAL;

 	if (tb[NFTA_DYNSET_EXPR]) {
 		struct nft_expr *dynset_expr;

 		dynset_expr = nft_dynset_expr_alloc(ctx, set,
 						    tb[NFTA_DYNSET_EXPR], 0);
 		if (IS_ERR(dynset_expr))
 			return PTR_ERR(dynset_expr);

 		priv->num_exprs++;
 		priv->expr_array[0] = dynset_expr;

 		if (set->num_exprs > 1 ||
 		    (set->num_exprs == 1 &&
 		     dynset_expr->ops != set->exprs[0]->ops)) {
 			err = -EOPNOTSUPP;
 			goto err_expr_free;
 		}
 	} else if (tb[NFTA_DYNSET_EXPRESSIONS]) {
 		struct nft_expr *dynset_expr;
 		struct nlattr *tmp;
 		int left;

 		if (!priv->expr)
 			return -EINVAL;

 		i = 0;
 		nla_for_each_nested(tmp, tb[NFTA_DYNSET_EXPRESSIONS], left) {
 			if (i == NFT_SET_EXPR_MAX) {
 				err = -E2BIG;
 				goto err_expr_free;
 			}
 			if (nla_type(tmp) != NFTA_LIST_ELEM) {
 				err = -EINVAL;
 				goto err_expr_free;
 			}
 			dynset_expr = nft_dynset_expr_alloc(ctx, set, tmp, i);
 			if (IS_ERR(dynset_expr)) {
 				err = PTR_ERR(dynset_expr);
 				goto err_expr_free;
 			}
 			priv->expr_array[i] = dynset_expr;
 			priv->num_exprs++;

 			if (set->num_exprs &&
 			    dynset_expr->ops != set->exprs[i]->ops) {
 				err = -EOPNOTSUPP;
 				goto err_expr_free;
 			}
 			i++;
 		}
 		if (set->num_exprs && set->num_exprs != i) {
 			err = -EOPNOTSUPP;
 			goto err_expr_free;
 		}
 	} else if (set->num_exprs > 0) {
 		err = nft_set_elem_expr_clone(ctx, set, priv->expr_array);
 		if (err < 0)
 			return err;

 		priv->num_exprs = set->num_exprs;
 	}

 	nft_set_ext_prepare(&priv->tmpl);
 	nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
 	if (set->flags & NFT_SET_MAP)
 		nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);

 	if (priv->num_exprs)
 		nft_dynset_ext_add_expr(priv);

 	if (set->flags & NFT_SET_TIMEOUT) {
 		if (timeout || set->timeout) {
 			nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_TIMEOUT);
 			nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION);
 		}
 	}

 	priv->timeout = timeout;

 	err = nf_tables_bind_set(ctx, set, &priv->binding);
 	if (err < 0)
 		goto err_expr_free;

 	if (set->size == 0)
 		set->size = 0xffff;

 	priv->set = set;
 	return 0;

 err_expr_free:
 	for (i = 0; i < priv->num_exprs; i++)
 		nft_expr_destroy(ctx, priv->expr_array[i]);
 	return err;
 }

 static void nft_dynset_deactivate(const struct nft_ctx *ctx,
 				  const struct nft_expr *expr,
 				  enum nft_trans_phase phase)
 {
 	struct nft_dynset *priv = nft_expr_priv(expr);

 	nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
 }

 static void nft_dynset_activate(const struct nft_ctx *ctx,
 				const struct nft_expr *expr)
 {
 	struct nft_dynset *priv = nft_expr_priv(expr);

 	priv->set->use++;
 }

 static void nft_dynset_destroy(const struct nft_ctx *ctx,
 			       const struct nft_expr *expr)
 {
 	struct nft_dynset *priv = nft_expr_priv(expr);
 	int i;

 	for (i = 0; i < priv->num_exprs; i++)
 		nft_expr_destroy(ctx, priv->expr_array[i]);

 	nf_tables_destroy_set(ctx, priv->set);
 }

 static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr)
 {
 	const struct nft_dynset *priv = nft_expr_priv(expr);
 	u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0;
 	int i;

 	if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key))
 		goto nla_put_failure;
 	if (priv->set->flags & NFT_SET_MAP &&
 	    nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data))
 		goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op)))
 		goto nla_put_failure;
 	if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name))
 		goto nla_put_failure;
 	if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT,
 			 nf_jiffies64_to_msecs(priv->timeout),
 			 NFTA_DYNSET_PAD))
 		goto nla_put_failure;
 	if (priv->set->num_exprs == 0) {
 		if (priv->num_exprs == 1) {
 			if (nft_expr_dump(skb, NFTA_DYNSET_EXPR,
 					  priv->expr_array[0]))
 				goto nla_put_failure;
 		} else if (priv->num_exprs > 1) {
 			struct nlattr *nest;

 			nest = nla_nest_start_noflag(skb, NFTA_DYNSET_EXPRESSIONS);
 			if (!nest)
 				goto nla_put_failure;

 			for (i = 0; i < priv->num_exprs; i++) {
 				if (nft_expr_dump(skb, NFTA_LIST_ELEM,
 						  priv->expr_array[i]))
 					goto nla_put_failure;
 			}
 			nla_nest_end(skb, nest);
 		}
 	}
 	if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags)))
 		goto nla_put_failure;
 	return 0;

 nla_put_failure:
 	return -1;
 }

 static const struct nft_expr_ops nft_dynset_ops = {
 	.type		= &nft_dynset_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_dynset)),
 	.eval		= nft_dynset_eval,
 	.init		= nft_dynset_init,
 	.destroy	= nft_dynset_destroy,
 	.activate	= nft_dynset_activate,
 	.deactivate	= nft_dynset_deactivate,
 	.dump		= nft_dynset_dump,
 };

 struct nft_expr_type nft_dynset_type __read_mostly = {
 	.name		= "dynset",
 	.ops		= &nft_dynset_ops,
 	.policy		= nft_dynset_policy,
 	.maxattr	= NFTA_DYNSET_MAX,
 	.owner		= THIS_MODULE,
 };
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (c) 2015 Patrick McHardy <kaber@trash.net>
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/init.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_dynset {
	struct nft_set *set;
	struct nft_set_ext_tmpl tmpl;
	enum nft_dynset_ops op:8;
	u8 sreg_key;
	u8 sreg_data;
	bool invert;
	bool expr;
	u8 num_exprs;
	u64 timeout;
	struct nft_expr *expr_array[NFT_SET_EXPR_MAX];
	struct nft_set_binding binding;
	};

	static int nft_dynset_expr_setup(const struct nft_dynset *priv,
	const struct nft_set_ext *ext)
	{
	struct nft_set_elem_expr *elem_expr = nft_set_ext_expr(ext);
	struct nft_expr *expr;
	int i;

	for (i = 0; i < priv->num_exprs; i++) {
	expr = nft_setelem_expr_at(elem_expr, elem_expr->size);
	if (nft_expr_clone(expr, priv->expr_array[i]) < 0)
	return -1;

	elem_expr->size += priv->expr_array[i]->ops->size;
	}

	return 0;
	}

	static void nft_dynset_new(struct nft_set set, const struct nft_expr *expr,
	struct nft_regs *regs)
	{
	const struct nft_dynset *priv = nft_expr_priv(expr);
	struct nft_set_ext *ext;
	u64 timeout;
	void *elem;

	if (!atomic_add_unless(&set->nelems, 1, set->size))
	return NULL;

	timeout = priv->timeout ? : set->timeout;
	elem = nft_set_elem_init(set, &priv->tmpl,
	&regs->data[priv->sreg_key], NULL,
	&regs->data[priv->sreg_data],
	timeout, 0, GFP_ATOMIC);
	if (elem == NULL)
	goto err1;

	ext = nft_set_elem_ext(set, elem);
	if (priv->num_exprs && nft_dynset_expr_setup(priv, ext) < 0)
	goto err2;

	return elem;

	err2:
	nft_set_elem_destroy(set, elem, false);
	err1:
	if (set->size)
	atomic_dec(&set->nelems);
	return NULL;
	}

	void nft_dynset_eval(const struct nft_expr *expr,
	struct nft_regs regs, const struct nft_pktinfo pkt)
	{
	const struct nft_dynset *priv = nft_expr_priv(expr);
	struct nft_set *set = priv->set;
	const struct nft_set_ext *ext;
	u64 timeout;

	if (priv->op == NFT_DYNSET_OP_DELETE) {
	set->ops->delete(set, &regs->data[priv->sreg_key]);
	return;
	}

	if (set->ops->update(set, &regs->data[priv->sreg_key], nft_dynset_new,
	expr, regs, &ext)) {
	if (priv->op == NFT_DYNSET_OP_UPDATE &&
	nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
	timeout = priv->timeout ? : set->timeout;
	*nft_set_ext_expiration(ext) = get_jiffies_64() + timeout;
	}

	nft_set_elem_update_expr(ext, regs, pkt);

	if (priv->invert)
	regs->verdict.code = NFT_BREAK;
	return;
	}

	if (!priv->invert)
	regs->verdict.code = NFT_BREAK;
	}

	static void nft_dynset_ext_add_expr(struct nft_dynset *priv)
	{
	u8 size = 0;
	int i;

	for (i = 0; i < priv->num_exprs; i++)
	size += priv->expr_array[i]->ops->size;

	nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPRESSIONS,
	sizeof(struct nft_set_elem_expr) + size);
	}

	static struct nft_expr *
	nft_dynset_expr_alloc(const struct nft_ctx ctx, const struct nft_set set,
	const struct nlattr *attr, int pos)
	{
	struct nft_expr *expr;
	int err;

	expr = nft_set_elem_expr_alloc(ctx, set, attr);
	if (IS_ERR(expr))
	return expr;

	if (set->exprs[pos] && set->exprs[pos]->ops != expr->ops) {
	err = -EOPNOTSUPP;
	goto err_dynset_expr;
	}

	return expr;

	err_dynset_expr:
	nft_expr_destroy(ctx, expr);
	return ERR_PTR(err);
	}

	static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
	[NFTA_DYNSET_SET_NAME] = { .type = NLA_STRING,
	.len = NFT_SET_MAXNAMELEN - 1 },
	[NFTA_DYNSET_SET_ID] = { .type = NLA_U32 },
	[NFTA_DYNSET_OP] = { .type = NLA_U32 },
	[NFTA_DYNSET_SREG_KEY] = { .type = NLA_U32 },
	[NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 },
	[NFTA_DYNSET_TIMEOUT] = { .type = NLA_U64 },
	[NFTA_DYNSET_EXPR] = { .type = NLA_NESTED },
	[NFTA_DYNSET_FLAGS] = { .type = NLA_U32 },
	[NFTA_DYNSET_EXPRESSIONS] = { .type = NLA_NESTED },
	};

	static int nft_dynset_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr * const tb[])
	{
	struct nft_dynset *priv = nft_expr_priv(expr);
	u8 genmask = nft_genmask_next(ctx->net);
	struct nft_set *set;
	u64 timeout;
	int err, i;

	lockdep_assert_held(&ctx->net->nft.commit_mutex);

	if (tb[NFTA_DYNSET_SET_NAME] == NULL \|\|
	tb[NFTA_DYNSET_OP] == NULL \|\|
	tb[NFTA_DYNSET_SREG_KEY] == NULL)
	return -EINVAL;

	if (tb[NFTA_DYNSET_FLAGS]) {
	u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS]));
	if (flags & ~(NFT_DYNSET_F_INV \| NFT_DYNSET_F_EXPR))
	return -EOPNOTSUPP;
	if (flags & NFT_DYNSET_F_INV)
	priv->invert = true;
	if (flags & NFT_DYNSET_F_EXPR)
	priv->expr = true;
	}

	set = nft_set_lookup_global(ctx->net, ctx->table,
	tb[NFTA_DYNSET_SET_NAME],
	tb[NFTA_DYNSET_SET_ID], genmask);
	if (IS_ERR(set))
	return PTR_ERR(set);

	if (set->ops->update == NULL)
	return -EOPNOTSUPP;

	if (set->flags & NFT_SET_CONSTANT)
	return -EBUSY;

	priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
	switch (priv->op) {
	case NFT_DYNSET_OP_ADD:
	case NFT_DYNSET_OP_DELETE:
	break;
	case NFT_DYNSET_OP_UPDATE:
	if (!(set->flags & NFT_SET_TIMEOUT))
	return -EOPNOTSUPP;
	break;
	default:
	return -EOPNOTSUPP;
	}

	timeout = 0;
	if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
	if (!(set->flags & NFT_SET_TIMEOUT))
	return -EOPNOTSUPP;

	err = nf_msecs_to_jiffies64(tb[NFTA_DYNSET_TIMEOUT], &timeout);
	if (err)
	return err;
	}

	err = nft_parse_register_load(tb[NFTA_DYNSET_SREG_KEY], &priv->sreg_key,
	set->klen);
	if (err < 0)
	return err;

	if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
	if (!(set->flags & NFT_SET_MAP))
	return -EOPNOTSUPP;
	if (set->dtype == NFT_DATA_VERDICT)
	return -EOPNOTSUPP;

	err = nft_parse_register_load(tb[NFTA_DYNSET_SREG_DATA],
	&priv->sreg_data, set->dlen);
	if (err < 0)
	return err;
	} else if (set->flags & NFT_SET_MAP)
	return -EINVAL;

	if ((tb[NFTA_DYNSET_EXPR] \|\| tb[NFTA_DYNSET_EXPRESSIONS]) &&
	!(set->flags & NFT_SET_EVAL))
	return -EINVAL;

	if (tb[NFTA_DYNSET_EXPR]) {
	struct nft_expr *dynset_expr;

	dynset_expr = nft_dynset_expr_alloc(ctx, set,
	tb[NFTA_DYNSET_EXPR], 0);
	if (IS_ERR(dynset_expr))
	return PTR_ERR(dynset_expr);

	priv->num_exprs++;
	priv->expr_array[0] = dynset_expr;

	if (set->num_exprs > 1 \|\|
	(set->num_exprs == 1 &&
	dynset_expr->ops != set->exprs[0]->ops)) {
	err = -EOPNOTSUPP;
	goto err_expr_free;
	}
	} else if (tb[NFTA_DYNSET_EXPRESSIONS]) {
	struct nft_expr *dynset_expr;
	struct nlattr *tmp;
	int left;

	if (!priv->expr)
	return -EINVAL;

	i = 0;
	nla_for_each_nested(tmp, tb[NFTA_DYNSET_EXPRESSIONS], left) {
	if (i == NFT_SET_EXPR_MAX) {
	err = -E2BIG;
	goto err_expr_free;
	}
	if (nla_type(tmp) != NFTA_LIST_ELEM) {
	err = -EINVAL;
	goto err_expr_free;
	}
	dynset_expr = nft_dynset_expr_alloc(ctx, set, tmp, i);
	if (IS_ERR(dynset_expr)) {
	err = PTR_ERR(dynset_expr);
	goto err_expr_free;
	}
	priv->expr_array[i] = dynset_expr;
	priv->num_exprs++;

	if (set->num_exprs &&
	dynset_expr->ops != set->exprs[i]->ops) {
	err = -EOPNOTSUPP;
	goto err_expr_free;
	}
	i++;
	}
	if (set->num_exprs && set->num_exprs != i) {
	err = -EOPNOTSUPP;
	goto err_expr_free;
	}
	} else if (set->num_exprs > 0) {
	err = nft_set_elem_expr_clone(ctx, set, priv->expr_array);
	if (err < 0)
	return err;

	priv->num_exprs = set->num_exprs;
	}

	nft_set_ext_prepare(&priv->tmpl);
	nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
	if (set->flags & NFT_SET_MAP)
	nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);

	if (priv->num_exprs)
	nft_dynset_ext_add_expr(priv);

	if (set->flags & NFT_SET_TIMEOUT) {
	if (timeout \|\| set->timeout) {
	nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_TIMEOUT);
	nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION);
	}
	}

	priv->timeout = timeout;

	err = nf_tables_bind_set(ctx, set, &priv->binding);
	if (err < 0)
	goto err_expr_free;

	if (set->size == 0)
	set->size = 0xffff;

	priv->set = set;
	return 0;

	err_expr_free:
	for (i = 0; i < priv->num_exprs; i++)
	nft_expr_destroy(ctx, priv->expr_array[i]);
	return err;
	}

	static void nft_dynset_deactivate(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	enum nft_trans_phase phase)
	{
	struct nft_dynset *priv = nft_expr_priv(expr);

	nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
	}

	static void nft_dynset_activate(const struct nft_ctx *ctx,
	const struct nft_expr *expr)
	{
	struct nft_dynset *priv = nft_expr_priv(expr);

	priv->set->use++;
	}

	static void nft_dynset_destroy(const struct nft_ctx *ctx,
	const struct nft_expr *expr)
	{
	struct nft_dynset *priv = nft_expr_priv(expr);
	int i;

	for (i = 0; i < priv->num_exprs; i++)
	nft_expr_destroy(ctx, priv->expr_array[i]);

	nf_tables_destroy_set(ctx, priv->set);
	}

	static int nft_dynset_dump(struct sk_buff skb, const struct nft_expr expr)
	{
	const struct nft_dynset *priv = nft_expr_priv(expr);
	u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0;
	int i;

	if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key))
	goto nla_put_failure;
	if (priv->set->flags & NFT_SET_MAP &&
	nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data))
	goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op)))
	goto nla_put_failure;
	if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name))
	goto nla_put_failure;
	if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT,
	nf_jiffies64_to_msecs(priv->timeout),
	NFTA_DYNSET_PAD))
	goto nla_put_failure;
	if (priv->set->num_exprs == 0) {
	if (priv->num_exprs == 1) {
	if (nft_expr_dump(skb, NFTA_DYNSET_EXPR,
	priv->expr_array[0]))
	goto nla_put_failure;
	} else if (priv->num_exprs > 1) {
	struct nlattr *nest;

	nest = nla_nest_start_noflag(skb, NFTA_DYNSET_EXPRESSIONS);
	if (!nest)
	goto nla_put_failure;

	for (i = 0; i < priv->num_exprs; i++) {
	if (nft_expr_dump(skb, NFTA_LIST_ELEM,
	priv->expr_array[i]))
	goto nla_put_failure;
	}
	nla_nest_end(skb, nest);
	}
	}
	if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags)))
	goto nla_put_failure;
	return 0;

	nla_put_failure:
	return -1;
	}

	static const struct nft_expr_ops nft_dynset_ops = {
	.type = &nft_dynset_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_dynset)),
	.eval = nft_dynset_eval,
	.init = nft_dynset_init,
	.destroy = nft_dynset_destroy,
	.activate = nft_dynset_activate,
	.deactivate = nft_dynset_deactivate,
	.dump = nft_dynset_dump,
	};

	struct nft_expr_type nft_dynset_type __read_mostly = {
	.name = "dynset",
	.ops = &nft_dynset_ops,
	.policy = nft_dynset_policy,
	.maxattr = NFTA_DYNSET_MAX,
	.owner = THIS_MODULE,
	};