net/netfilter/nf_tables_api.c

/*
 * Copyright (c) 2007-2009 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/module.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/vmalloc.h>
#include <linux/rhashtable.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_flow_table.h>
#include <net/netfilter/nf_tables_core.h>
#include <net/netfilter/nf_tables.h>
#include <net/net_namespace.h>
#include <net/sock.h>

#define NFT_MODULE_AUTOLOAD_LIMIT (MODULE_NAME_LEN - sizeof("nft-expr-255-"))

static LIST_HEAD(nf_tables_expressions);
static LIST_HEAD(nf_tables_objects);
static LIST_HEAD(nf_tables_flowtables);
static u64 table_handle;

enum {
	NFT_VALIDATE_SKIP	= 0,
	NFT_VALIDATE_NEED,
	NFT_VALIDATE_DO,
};

static u32 nft_chain_hash(const void *data, u32 len, u32 seed);
static u32 nft_chain_hash_obj(const void *data, u32 len, u32 seed);
static int nft_chain_hash_cmp(struct rhashtable_compare_arg *, const void *);

static const struct rhashtable_params nft_chain_ht_params = {
	.head_offset		= offsetof(struct nft_chain, rhlhead),
	.key_offset		= offsetof(struct nft_chain, name),
	.hashfn			= nft_chain_hash,
	.obj_hashfn		= nft_chain_hash_obj,
	.obj_cmpfn		= nft_chain_hash_cmp,
	.locks_mul		= 1,
	.automatic_shrinking	= true,
};

static void nft_validate_state_update(struct net *net, u8 new_validate_state)
{
	switch (net->nft.validate_state) {
	case NFT_VALIDATE_SKIP:
		WARN_ON_ONCE(new_validate_state == NFT_VALIDATE_DO);
		break;
	case NFT_VALIDATE_NEED:
		break;
	case NFT_VALIDATE_DO:
		if (new_validate_state == NFT_VALIDATE_NEED)
			return;
	}

	net->nft.validate_state = new_validate_state;
}

static void nft_ctx_init(struct nft_ctx *ctx,
			 struct net *net,
			 const struct sk_buff *skb,
			 const struct nlmsghdr *nlh,
			 u8 family,
			 struct nft_table *table,
			 struct nft_chain *chain,
			 const struct nlattr * const *nla)
{
	ctx->net	= net;
	ctx->family	= family;
	ctx->level	= 0;
	ctx->table	= table;
	ctx->chain	= chain;
	ctx->nla   	= nla;
	ctx->portid	= NETLINK_CB(skb).portid;
	ctx->report	= nlmsg_report(nlh);
	ctx->seq	= nlh->nlmsg_seq;
}

static struct nft_trans *nft_trans_alloc_gfp(const struct nft_ctx *ctx,
					     int msg_type, u32 size, gfp_t gfp)
{
	struct nft_trans *trans;

	trans = kzalloc(sizeof(struct nft_trans) + size, gfp);
	if (trans == NULL)
		return NULL;

	trans->msg_type = msg_type;
	trans->ctx	= *ctx;

	return trans;
}

static struct nft_trans *nft_trans_alloc(const struct nft_ctx *ctx,
					 int msg_type, u32 size)
{
	return nft_trans_alloc_gfp(ctx, msg_type, size, GFP_KERNEL);
}

static void nft_trans_destroy(struct nft_trans *trans)
{
	list_del(&trans->list);
	kfree(trans);
}

static void nft_set_trans_bind(const struct nft_ctx *ctx, struct nft_set *set)
{
	struct net *net = ctx->net;
	struct nft_trans *trans;

	if (!nft_set_is_anonymous(set))
		return;

	list_for_each_entry_reverse(trans, &net->nft.commit_list, list) {
		switch (trans->msg_type) {
		case NFT_MSG_NEWSET:
			if (nft_trans_set(trans) == set)
				nft_trans_set_bound(trans) = true;
			break;
		case NFT_MSG_NEWSETELEM:
			if (nft_trans_elem_set(trans) == set)
				nft_trans_elem_set_bound(trans) = true;
			break;
		}
	}
}

static int nf_tables_register_hook(struct net *net,
				   const struct nft_table *table,
				   struct nft_chain *chain)
{
	const struct nft_base_chain *basechain;
	const struct nf_hook_ops *ops;

	if (table->flags & NFT_TABLE_F_DORMANT ||
	    !nft_is_base_chain(chain))
		return 0;

	basechain = nft_base_chain(chain);
	ops = &basechain->ops;

	if (basechain->type->ops_register)
		return basechain->type->ops_register(net, ops);

	return nf_register_net_hook(net, ops);
}

static void nf_tables_unregister_hook(struct net *net,
				      const struct nft_table *table,
				      struct nft_chain *chain)
{
	const struct nft_base_chain *basechain;
	const struct nf_hook_ops *ops;

	if (table->flags & NFT_TABLE_F_DORMANT ||
	    !nft_is_base_chain(chain))
		return;
	basechain = nft_base_chain(chain);
	ops = &basechain->ops;

	if (basechain->type->ops_unregister)
		return basechain->type->ops_unregister(net, ops);

	nf_unregister_net_hook(net, ops);
}

static int nft_trans_table_add(struct nft_ctx *ctx, int msg_type)
{
	struct nft_trans *trans;

	trans = nft_trans_alloc(ctx, msg_type, sizeof(struct nft_trans_table));
	if (trans == NULL)
		return -ENOMEM;

	if (msg_type == NFT_MSG_NEWTABLE)
		nft_activate_next(ctx->net, ctx->table);

	list_add_tail(&trans->list, &ctx->net->nft.commit_list);
	return 0;
}

static int nft_deltable(struct nft_ctx *ctx)
{
	int err;

	err = nft_trans_table_add(ctx, NFT_MSG_DELTABLE);
	if (err < 0)
		return err;

	nft_deactivate_next(ctx->net, ctx->table);
	return err;
}

static int nft_trans_chain_add(struct nft_ctx *ctx, int msg_type)
{
	struct nft_trans *trans;

	trans = nft_trans_alloc(ctx, msg_type, sizeof(struct nft_trans_chain));
	if (trans == NULL)
		return -ENOMEM;

	if (msg_type == NFT_MSG_NEWCHAIN)
		nft_activate_next(ctx->net, ctx->chain);

	list_add_tail(&trans->list, &ctx->net->nft.commit_list);
	return 0;
}

static int nft_delchain(struct nft_ctx *ctx)
{
	int err;

	err = nft_trans_chain_add(ctx, NFT_MSG_DELCHAIN);
	if (err < 0)
		return err;

	ctx->table->use--;
	nft_deactivate_next(ctx->net, ctx->chain);

	return err;
}

static void nft_rule_expr_activate(const struct nft_ctx *ctx,
				   struct nft_rule *rule)
{
	struct nft_expr *expr;

	expr = nft_expr_first(rule);
	while (expr != nft_expr_last(rule) && expr->ops) {
		if (expr->ops->activate)
			expr->ops->activate(ctx, expr);

		expr = nft_expr_next(expr);
	}
}

static void nft_rule_expr_deactivate(const struct nft_ctx *ctx,
				     struct nft_rule *rule,
				     enum nft_trans_phase phase)
{
	struct nft_expr *expr;

	expr = nft_expr_first(rule);
	while (expr != nft_expr_last(rule) && expr->ops) {
		if (expr->ops->deactivate)
			expr->ops->deactivate(ctx, expr, phase);

		expr = nft_expr_next(expr);
	}
}

static int
nf_tables_delrule_deactivate(struct nft_ctx *ctx, struct nft_rule *rule)
{
	/* You cannot delete the same rule twice */
	if (nft_is_active_next(ctx->net, rule)) {
		nft_deactivate_next(ctx->net, rule);
		ctx->chain->use--;
		return 0;
	}
	return -ENOENT;
}

static struct nft_trans *nft_trans_rule_add(struct nft_ctx *ctx, int msg_type,
					    struct nft_rule *rule)
{
	struct nft_trans *trans;

	trans = nft_trans_alloc(ctx, msg_type, sizeof(struct nft_trans_rule));
	if (trans == NULL)
		return NULL;

	if (msg_type == NFT_MSG_NEWRULE && ctx->nla[NFTA_RULE_ID] != NULL) {
		nft_trans_rule_id(trans) =
			ntohl(nla_get_be32(ctx->nla[NFTA_RULE_ID]));
	}
	nft_trans_rule(trans) = rule;
	list_add_tail(&trans->list, &ctx->net->nft.commit_list);

	return trans;
}

static int nft_delrule(struct nft_ctx *ctx, struct nft_rule *rule)
{
	struct nft_trans *trans;
	int err;

	trans = nft_trans_rule_add(ctx, NFT_MSG_DELRULE, rule);
	if (trans == NULL)
		return -ENOMEM;

	err = nf_tables_delrule_deactivate(ctx, rule);
	if (err < 0) {
		nft_trans_destroy(trans);
		return err;
	}
	nft_rule_expr_deactivate(ctx, rule, NFT_TRANS_PREPARE);

	return 0;
}

static int nft_delrule_by_chain(struct nft_ctx *ctx)
{
	struct nft_rule *rule;
	int err;

	list_for_each_entry(rule, &ctx->chain->rules, list) {
		if (!nft_is_active_next(ctx->net, rule))
			continue;

		err = nft_delrule(ctx, rule);
		if (err < 0)
			return err;
	}
	return 0;
}

static int nft_trans_set_add(const struct nft_ctx *ctx, int msg_type,
			     struct nft_set *set)
{
	struct nft_trans *trans;

	trans = nft_trans_alloc(ctx, msg_type, sizeof(struct nft_trans_set));
	if (trans == NULL)
		return -ENOMEM;

	if (msg_type == NFT_MSG_NEWSET && ctx->nla[NFTA_SET_ID] != NULL) {
		nft_trans_set_id(trans) =
			ntohl(nla_get_be32(ctx->nla[NFTA_SET_ID]));
		nft_activate_next(ctx->net, set);
	}
	nft_trans_set(trans) = set;
	list_add_tail(&trans->list, &ctx->net->nft.commit_list);

	return 0;
}

static int nft_delset(const struct nft_ctx *ctx, struct nft_set *set)
{
	int err;

	err = nft_trans_set_add(ctx, NFT_MSG_DELSET, set);
	if (err < 0)
		return err;

	nft_deactivate_next(ctx->net, set);
	ctx->table->use--;

	return err;
}

static int nft_trans_obj_add(struct nft_ctx *ctx, int msg_type,
			     struct nft_object *obj)
{
	struct nft_trans *trans;

	trans = nft_trans_alloc(ctx, msg_type, sizeof(struct nft_trans_obj));
	if (trans == NULL)
		return -ENOMEM;

	if (msg_type == NFT_MSG_NEWOBJ)
		nft_activate_next(ctx->net, obj);

	nft_trans_obj(trans) = obj;
	list_add_tail(&trans->list, &ctx->net->nft.commit_list);

	return 0;
}

static int nft_delobj(struct nft_ctx *ctx, struct nft_object *obj)
{
	int err;

	err = nft_trans_obj_add(ctx, NFT_MSG_DELOBJ, obj);
	if (err < 0)
		return err;

	nft_deactivate_next(ctx->net, obj);
	ctx->table->use--;

	return err;
}

static int nft_trans_flowtable_add(struct nft_ctx *ctx, int msg_type,
				   struct nft_flowtable *flowtable)
{
	struct nft_trans *trans;

	trans = nft_trans_alloc(ctx, msg_type,
				sizeof(struct nft_trans_flowtable));
	if (trans == NULL)
		return -ENOMEM;

	if (msg_type == NFT_MSG_NEWFLOWTABLE)
		nft_activate_next(ctx->net, flowtable);

	nft_trans_flowtable(trans) = flowtable;
	list_add_tail(&trans->list, &ctx->net->nft.commit_list);

	return 0;
}

static int nft_delflowtable(struct nft_ctx *ctx,
			    struct nft_flowtable *flowtable)
{
	int err;

	err = nft_trans_flowtable_add(ctx, NFT_MSG_DELFLOWTABLE, flowtable);
	if (err < 0)
		return err;

	nft_deactivate_next(ctx->net, flowtable);
	ctx->table->use--;

	return err;
}

/*
 * Tables
 */

static struct nft_table *nft_table_lookup(const struct net *net,
					  const struct nlattr *nla,
					  u8 family, u8 genmask)
{
	struct nft_table *table;

	if (nla == NULL)
		return ERR_PTR(-EINVAL);

	list_for_each_entry_rcu(table, &net->nft.tables, list) {
		if (!nla_strcmp(nla, table->name) &&
		    table->family == family &&
		    nft_active_genmask(table, genmask))
			return table;
	}

	return ERR_PTR(-ENOENT);
}

static struct nft_table *nft_table_lookup_byhandle(const struct net *net,
						   const struct nlattr *nla,
						   u8 genmask)
{
	struct nft_table *table;

	list_for_each_entry(table, &net->nft.tables, list) {
		if (be64_to_cpu(nla_get_be64(nla)) == table->handle &&
		    nft_active_genmask(table, genmask))
			return table;
	}

	return ERR_PTR(-ENOENT);
}

static inline u64 nf_tables_alloc_handle(struct nft_table *table)
{
	return ++table->hgenerator;
}

static const struct nft_chain_type *chain_type[NFPROTO_NUMPROTO][NFT_CHAIN_T_MAX];

static const struct nft_chain_type *
__nft_chain_type_get(u8 family, enum nft_chain_types type)
{
	if (family >= NFPROTO_NUMPROTO ||
	    type >= NFT_CHAIN_T_MAX)
		return NULL;

	return chain_type[family][type];
}

static const struct nft_chain_type *
__nf_tables_chain_type_lookup(const struct nlattr *nla, u8 family)
{
	const struct nft_chain_type *type;
	int i;

	for (i = 0; i < NFT_CHAIN_T_MAX; i++) {
		type = __nft_chain_type_get(family, i);
		if (!type)
			continue;
		if (!nla_strcmp(nla, type->name))
			return type;
	}
	return NULL;
}

/*
 * Loading a module requires dropping mutex that guards the transaction.
 * A different client might race to start a new transaction meanwhile. Zap the
 * list of pending transaction and then restore it once the mutex is grabbed
 * again. Users of this function return EAGAIN which implicitly triggers the
 * transaction abort path to clean up the list of pending transactions.
 */
#ifdef CONFIG_MODULES
static void nft_request_module(struct net *net, const char *fmt, ...)
{
	char module_name[MODULE_NAME_LEN];
	LIST_HEAD(commit_list);
	va_list args;
	int ret;

	list_splice_init(&net->nft.commit_list, &commit_list);

	va_start(args, fmt);
	ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args);
	va_end(args);
	if (ret >= MODULE_NAME_LEN)
		return;

	mutex_unlock(&net->nft.commit_mutex);
	request_module("%s", module_name);
	mutex_lock(&net->nft.commit_mutex);

	WARN_ON_ONCE(!list_empty(&net->nft.commit_list));
	list_splice(&commit_list, &net->nft.commit_list);
}
#endif

static void lockdep_nfnl_nft_mutex_not_held(void)
{
#ifdef CONFIG_PROVE_LOCKING
	WARN_ON_ONCE(lockdep_nfnl_is_held(NFNL_SUBSYS_NFTABLES));
#endif
}

static const struct nft_chain_type *
nf_tables_chain_type_lookup(struct net *net, const struct nlattr *nla,
			    u8 family, bool autoload)
{
	const struct nft_chain_type *type;

	type = __nf_tables_chain_type_lookup(nla, family);
	if (type != NULL)
		return type;

	lockdep_nfnl_nft_mutex_not_held();
#ifdef CONFIG_MODULES
	if (autoload) {
		nft_request_module(net, "nft-chain-%u-%.*s", family,
				   nla_len(nla), (const char *)nla_data(nla));
		type = __nf_tables_chain_type_lookup(nla, family);
		if (type != NULL)
			return ERR_PTR(-EAGAIN);
	}
#endif
	return ERR_PTR(-ENOENT);
}

static const struct nla_policy nft_table_policy[NFTA_TABLE_MAX + 1] = {
	[NFTA_TABLE_NAME]	= { .type = NLA_STRING,
				    .len = NFT_TABLE_MAXNAMELEN - 1 },
	[NFTA_TABLE_FLAGS]	= { .type = NLA_U32 },
	[NFTA_TABLE_HANDLE]	= { .type = NLA_U64 },
};

static int nf_tables_fill_table_info(struct sk_buff *skb, struct net *net,
				     u32 portid, u32 seq, int event, u32 flags,
				     int family, const struct nft_table *table)
{
	struct nlmsghdr *nlh;
	struct nfgenmsg *nfmsg;

	event = nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event);
	nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct nfgenmsg), flags);
	if (nlh == NULL)
		goto nla_put_failure;

	nfmsg = nlmsg_data(nlh);
	nfmsg->nfgen_family	= family;
	nfmsg->version		= NFNETLINK_V0;
	nfmsg->res_id		= htons(net->nft.base_seq & 0xffff);

	if (nla_put_string(skb, NFTA_TABLE_NAME, table->name) ||
	    nla_put_be32(skb, NFTA_TABLE_FLAGS, htonl(table->flags)) ||
	    nla_put_be32(skb, NFTA_TABLE_USE, htonl(table->use)) ||
	    nla_put_be64(skb, NFTA_TABLE_HANDLE, cpu_to_be64(table->handle),
			 NFTA_TABLE_PAD))
		goto nla_put_failure;

	nlmsg_end(skb, nlh);
	return 0;

nla_put_failure:
	nlmsg_trim(skb, nlh);
	return -1;
}

static void nf_tables_table_notify(const struct nft_ctx *ctx, int event)
{
	struct sk_buff *skb;
	int err;

	if (!ctx->report &&
	    !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
		return;

	skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
	if (skb == NULL)
		goto err;

	err = nf_tables_fill_table_info(skb, ctx->net, ctx->portid, ctx->seq,
					event, 0, ctx->family, ctx->table);
	if (err < 0) {
		kfree_skb(skb);
		goto err;
	}

	nfnetlink_send(skb, ctx->net, ctx->portid, NFNLGRP_NFTABLES,
		       ctx->report, GFP_KERNEL);
	return;
err:
	nfnetlink_set_err(ctx->net, ctx->portid, NFNLGRP_NFTABLES, -ENOBUFS);
}

static int nf_tables_dump_tables(struct sk_buff *skb,
				 struct netlink_callback *cb)
{
	const struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh);
	const struct nft_table *table;
	unsigned int idx = 0, s_idx = cb->args[0];
	struct net *net = sock_net(skb->sk);
	int family = nfmsg->nfgen_family;

	rcu_read_lock();
	cb->seq = net->nft.base_seq;

	list_for_each_entry_rcu(table, &net->nft.tables, list) {
		if (family != NFPROTO_UNSPEC && family != table->family)
			continue;

		if (idx < s_idx)
			goto cont;
		if (idx > s_idx)
			memset(&cb->args[1], 0,
			       sizeof(cb->args) - sizeof(cb->args[0]));
		if (!nft_is_active(net, table))
			continue;
		if (nf_tables_fill_table_info(skb, net,
					      NETLINK_CB(cb->skb).portid,
					      cb->nlh->nlmsg_seq,
					      NFT_MSG_NEWTABLE, NLM_F_MULTI,
					      table->family, table) < 0)
			goto done;

		nl_dump_check_consistent(cb, nlmsg_hdr(skb));
cont:
		idx++;
	}
done:
	rcu_read_unlock();
	cb->args[0] = idx;
	return skb->len;
}

static int nft_netlink_dump_start_rcu(struct sock *nlsk, struct sk_buff *skb,
				      const struct nlmsghdr *nlh,
				      struct netlink_dump_control *c)
{
	int err;

	if (!try_module_get(THIS_MODULE))
		return -EINVAL;

	rcu_read_unlock();
	err = netlink_dump_start(nlsk, skb, nlh, c);
	rcu_read_lock();
	module_put(THIS_MODULE);

	return err;
}

/* called with rcu_read_lock held */
static int nf_tables_gettable(struct net *net, struct sock *nlsk,
			      struct sk_buff *skb, const struct nlmsghdr *nlh,
			      const struct nlattr * const nla[],
			      struct netlink_ext_ack *extack)
{
	const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
	u8 genmask = nft_genmask_cur(net);
	const struct nft_table *table;
	struct sk_buff *skb2;
	int family = nfmsg->nfgen_family;
	int err;

	if (nlh->nlmsg_flags & NLM_F_DUMP) {
		struct netlink_dump_control c = {
			.dump = nf_tables_dump_tables,
			.module = THIS_MODULE,
		};

		return nft_netlink_dump_start_rcu(nlsk, skb, nlh, &c);
	}

	table = nft_table_lookup(net, nla[NFTA_TABLE_NAME], family, genmask);
	if (IS_ERR(table)) {
		NL_SET_BAD_ATTR(extack, nla[NFTA_TABLE_NAME]);
		return PTR_ERR(table);
	}

	skb2 = alloc_skb(NLMSG_GOODSIZE, GFP_ATOMIC);
	if (!skb2)
		return -ENOMEM;

	err = nf_tables_fill_table_info(skb2, net, NETLINK_CB(skb).portid,
					nlh->nlmsg_seq, NFT_MSG_NEWTABLE, 0,
					family, table);
	if (err < 0)
		goto err;

	return nlmsg_unicast(nlsk, skb2, NETLINK_CB(skb).portid);

err:
	kfree_skb(skb2);
	return err;
}

static void nft_table_disable(struct net *net, struct nft_table *table, u32 cnt)
{
	struct nft_chain *chain;
	u32 i = 0;

	list_for_each_entry(chain, &table->chains, list) {
		if (!nft_is_active_next(net, chain))
			continue;
		if (!nft_is_base_chain(chain))
			continue;

		if (cnt && i++ == cnt)
			break;

		nf_unregister_net_hook(net, &nft_base_chain(chain)->ops);
	}
}

static int nf_tables_table_enable(struct net *net, struct nft_table *table)
{
	struct nft_chain *chain;
	int err, i = 0;

	list_for_each_entry(chain, &table->chains, list) {
		if (!nft_is_active_next(net, chain))
			continue;
		if (!nft_is_base_chain(chain))
			continue;

		err = nf_register_net_hook(net, &nft_base_chain(chain)->ops);
		if (err < 0)
			goto err;

		i++;
	}
	return 0;
err:
	if (i)
		nft_table_disable(net, table, i);
	return err;
}

static void nf_tables_table_disable(struct net *net, struct nft_table *table)
{
	nft_table_disable(net, table, 0);
}

static int nf_tables_updtable(struct nft_ctx *ctx)
{
	struct nft_trans *trans;
	u32 flags;
	int ret = 0;

	if (!ctx->nla[NFTA_TABLE_FLAGS])
		return 0;

	flags = ntohl(nla_get_be32(ctx->nla[NFTA_TABLE_FLAGS]));
	if (flags & ~NFT_TABLE_F_DORMANT)
		return -EINVAL;

	if (flags == ctx->table->flags)
		return 0;

	trans = nft_trans_alloc(ctx, NFT_MSG_NEWTABLE,
				sizeof(struct nft_trans_table));
	if (trans == NULL)
		return -ENOMEM;

	if ((flags & NFT_TABLE_F_DORMANT) &&
	    !(ctx->table->flags & NFT_TABLE_F_DORMANT)) {
		nft_trans_table_enable(trans) = false;
	} else if (!(flags & NFT_TABLE_F_DORMANT) &&
		   ctx->table->flags & NFT_TABLE_F_DORMANT) {
		ret = nf_tables_table_enable(ctx->net, ctx->table);
		if (ret >= 0) {
			ctx->table->flags &= ~NFT_TABLE_F_DORMANT;
			nft_trans_table_enable(trans) = true;
		}
	}
	if (ret < 0)
		goto err;

	nft_trans_table_update(trans) = true;
	list_add_tail(&trans->list, &ctx->net->nft.commit_list);
	return 0;
err:
	nft_trans_destroy(trans);
	return ret;
}

static u32 nft_chain_hash(const void *data, u32 len, u32 seed)
{
	const char *name = data;

	return jhash(name, strlen(name), seed);
}

static u32 nft_chain_hash_obj(const void *data, u32 len, u32 seed)
{
	const struct nft_chain *chain = data;

	return nft_chain_hash(chain->name, 0, seed);
}

static int nft_chain_hash_cmp(struct rhashtable_compare_arg *arg,
			      const void *ptr)
{
	const struct nft_chain *chain = ptr;
	const char *name = arg->key;

	return strcmp(chain->name, name);
}

static int nf_tables_newtable(struct net *net, struct sock *nlsk,
			      struct sk_buff *skb, const struct nlmsghdr *nlh,
			      const struct nlattr * const nla[],
			      struct netlink_ext_ack *extack)
{
	const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
	u8 genmask = nft_genmask_next(net);
	int family = nfmsg->nfgen_family;
	const struct nlattr *attr;
	struct nft_table *table;
	u32 flags = 0;
	struct nft_ctx ctx;
	int err;

	lockdep_assert_held(&net->nft.commit_mutex);
	attr = nla[NFTA_TABLE_NAME];
	table = nft_table_lookup(net, attr, family, genmask);
	if (IS_ERR(table)) {
		if (PTR_ERR(table) != -ENOENT)
			return PTR_ERR(table);
	} else {
		if (nlh->nlmsg_flags & NLM_F_EXCL) {
			NL_SET_BAD_ATTR(extack, attr);
			return -EEXIST;
		}
		if (nlh->nlmsg_flags & NLM_F_REPLACE)
			return -EOPNOTSUPP;

		nft_ctx_init(&ctx, net, skb, nlh, family, table, NULL, nla);
		return nf_tables_updtable(&ctx);
	}

	if (nla[NFTA_TABLE_FLAGS]) {
		flags = ntohl(nla_get_be32(nla[NFTA_TABLE_FLAGS]));
		if (flags & ~NFT_TABLE_F_DORMANT)
			return -EINVAL;
	}

	err = -ENOMEM;
	table = kzalloc(sizeof(*table), GFP_KERNEL);
	if (table == NULL)
		goto err_kzalloc;

	table->name = nla_strdup(attr, GFP_KERNEL);
	if (table->name == NULL)
		goto err_strdup;

	err = rhltable_init(&table->chains_ht, &nft_chain_ht_params);
	if (err)
		goto err_chain_ht;

	INIT_LIST_HEAD(&table->chains);
	INIT_LIST_HEAD(&table->sets);
	INIT_LIST_HEAD(&table->objects);
	INIT_LIST_HEAD(&table->flowtables);
	table->family = family;
	table->flags = flags;
	table->handle = ++table_handle;

	nft_ctx_init(&ctx, net, skb, nlh, family, table, NULL, nla);
	err = nft_trans_table_add(&ctx, NFT_MSG_NEWTABLE);
	if (err < 0)
		goto err_trans;

	list_add_tail_rcu(&table->list, &net->nft.tables);
	return 0;
err_trans:
	rhltable_destroy(&table->chains_ht);
err_chain_ht:
	kfree(table->name);
err_strdup:
	kfree(table);
err_kzalloc:
	return err;
}

static int nft_flush_table(struct nft_ctx *ctx)
{
	struct nft_flowtable *flowtable, *nft;
	struct nft_chain *chain, *nc;
	struct nft_object *obj, *ne;
	struct nft_set *set, *ns;
	int err;

	list_for_each_entry(chain, &ctx->table->chains, list) {
		if (!nft_is_active_next(ctx->net, chain))
			continue;

		ctx->chain = chain;

		err = nft_delrule_by_chain(ctx);
		if (err < 0)
			goto out;
	}

	list_for_each_entry_safe(set, ns, &ctx->table->sets, list) {
		if (!nft_is_active_next(ctx->net, set))
			continue;

		if (nft_set_is_anonymous(set) &&
		    !list_empty(&set->bindings))
			continue;

		err = nft_delset(ctx, set);
		if (err < 0)
			goto out;
	}

	list_for_each_entry_safe(flowtable, nft, &ctx->table->flowtables, list) {
		if (!nft_is_active_next(ctx->net, flowtable))
			continue;

		err = nft_delflowtable(ctx, flowtable);
		if (err < 0)
			goto out;
	}

	list_for_each_entry_safe(obj, ne, &ctx->table->objects, list) {
		if (!nft_is_active_next(ctx->net, obj))
			continue;

		err = nft_delobj(ctx, obj);
		if (err < 0)
			goto out;
	}

	list_for_each_entry_safe(chain, nc, &ctx->table->chains, list) {
		if (!nft_is_active_next(ctx->net, chain))
			continue;

		ctx->chain = chain;

		err = nft_delchain(ctx);
		if (err < 0)
			goto out;
	}

	err = nft_deltable(ctx);
out:
	return err;
}

static int nft_flush(struct nft_ctx *ctx, int family)
{
	struct nft_table *table, *nt;
	const struct nlattr * const *nla = ctx->nla;
	int err = 0;

	list_for_each_entry_safe(table, nt, &ctx->net->nft.tables, list) {
		if (family != AF_UNSPEC && table->family != family)
			continue;

		ctx->family = table->family;

		if (!nft_is_active_next(ctx->net, table))
			continue;

		if (nla[NFTA_TABLE_NAME] &&
		    nla_strcmp(nla[NFTA_TABLE_NAME], table->name) != 0)
			continue;

		ctx->table = table;

		err = nft_flush_table(ctx);
		if (err < 0)
			goto out;
	}
out:
	return err;
}

static int nf_tables_deltable(struct net *net, struct sock *nlsk,
			      struct sk_buff *skb, const struct nlmsghdr *nlh,
			      const struct nlattr * const nla[],
			      struct netlink_ext_ack *extack)
{
	const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
	u8 genmask = nft_genmask_next(net);
	int family = nfmsg->nfgen_family;
	const struct nlattr *attr;
	struct nft_table *table;
	struct nft_ctx ctx;

	nft_ctx_init(&ctx, net, skb, nlh, 0, NULL, NULL, nla);
	if (family == AF_UNSPEC ||
	    (!nla[NFTA_TABLE_NAME] && !nla[NFTA_TABLE_HANDLE]))
		return nft_flush(&ctx, family);

	if (nla[NFTA_TABLE_HANDLE]) {
		attr = nla[NFTA_TABLE_HANDLE];
		table = nft_table_lookup_byhandle(net, attr, genmask);
	} else {
		attr = nla[NFTA_TABLE_NAME];
		table = nft_table_lookup(net, attr, family, genmask);
	}

	if (IS_ERR(table)) {
		NL_SET_BAD_ATTR(extack, attr);
		return PTR_ERR(table);
	}

	if (nlh->nlmsg_flags & NLM_F_NONREC &&
	    table->use > 0)
		return -EBUSY;

	ctx.family = family;
	ctx.table = table;

	return nft_flush_table(&ctx);
}

static void nf_tables_table_destroy(struct nft_ctx *ctx)
{
	if (WARN_ON(ctx->table->use > 0))
		return;

	rhltable_destroy(&ctx->table->chains_ht);
	kfree(ctx->table->name);
	kfree(ctx->table);
}

void nft_register_chain_type(const struct nft_chain_type *ctype)
{
	nfnl_lock(NFNL_SUBSYS_NFTABLES);
	if (WARN_ON(__nft_chain_type_get(ctype->family, ctype->type))) {
		nfnl_unlock(NFNL_SUBSYS_NFTABLES);
		return;
	}
	chain_type[ctype->family][ctype->type] = ctype;
	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
}
EXPORT_SYMBOL_GPL(nft_register_chain_type);

void nft_unregister_chain_type(const struct nft_chain_type *ctype)
{
	nfnl_lock(NFNL_SUBSYS_NFTABLES);
	chain_type[ctype->family][ctype->type] = NULL;
	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
}
EXPORT_SYMBOL_GPL(nft_unregister_chain_type);

/*
 * Chains
 */

static struct nft_chain *
nft_chain_lookup_byhandle(const struct nft_table *table, u64 handle, u8 genmask)
{
	struct nft_chain *chain;

	list_for_each_entry(chain, &table->chains, list) {
		if (chain->handle == handle &&
		    nft_active_genmask(chain, genmask))
			return chain;
	}

	return ERR_PTR(-ENOENT);
}

static bool lockdep_commit_lock_is_held(struct net *net)
{
#ifdef CONFIG_PROVE_LOCKING
	return lockdep_is_held(&net->nft.commit_mutex);
#else
	return true;
#endif
}

static struct nft_chain *nft_chain_lookup(struct net *net,
					  struct nft_table *table,
					  const struct nlattr *nla, u8 genmask)
{
	char search[NFT_CHAIN_MAXNAMELEN + 1];
	struct rhlist_head *tmp, *list;
	struct nft_chain *chain;

	if (nla == NULL)
		return ERR_PTR(-EINVAL);

	nla_strlcpy(search, nla, sizeof(search));

	WARN_ON(!rcu_read_lock_held() &&
		!lockdep_commit_lock_is_held(net));

	chain = ERR_PTR(-ENOENT);
	rcu_read_lock();
	list = rhltable_lookup(&table->chains_ht, search, nft_chain_ht_params);
	if (!list)
		goto out_unlock;

	rhl_for_each_entry_rcu(chain, tmp, list, rhlhead) {
		if (nft_active_genmask(chain, genmask))
			goto out_unlock;
	}
	chain = ERR_PTR(-ENOENT);
out_unlock:
	rcu_read_unlock();
	return chain;
}

static const struct nla_policy nft_chain_policy[NFTA_CHAIN_MAX + 1] = {
	[NFTA_CHAIN_TABLE]	= { .type = NLA_STRING,
				    .len = NFT_TABLE_MAXNAMELEN - 1 },
	[NFTA_CHAIN_HANDLE]	= { .type = NLA_U64 },
	[NFTA_CHAIN_NAME]	= { .type = NLA_STRING,
				    .len = NFT_CHAIN_MAXNAMELEN - 1 },
	[NFTA_CHAIN_HOOK]	= { .type = NLA_NESTED },
	[NFTA_CHAIN_POLICY]	= { .type = NLA_U32 },
	[NFTA_CHAIN_TYPE]	= { .type = NLA_STRING,
				    .len = NFT_MODULE_AUTOLOAD_LIMIT },
	[NFTA_CHAIN_COUNTERS]	= { .type = NLA_NESTED },
};

static const struct nla_policy nft_hook_policy[NFTA_HOOK_MAX + 1] = {
	[NFTA_HOOK_HOOKNUM]	= { .type = NLA_U32 },
	[NFTA_HOOK_PRIORITY]	= { .type = NLA_U32 },
	[NFTA_HOOK_DEV]		= { .type = NLA_STRING,
				    .len = IFNAMSIZ - 1 },
};

static int nft_dump_stats(struct sk_buff *skb, struct nft_stats __percpu *stats)
{
	struct nft_stats *cpu_stats, total;
	struct nlattr *nest;
	unsigned int seq;
	u64 pkts, bytes;
	int cpu;

	if (!stats)
		return 0;

	memset(&total, 0, sizeof(total));
	for_each_possible_cpu(cpu) {
		cpu_stats = per_cpu_ptr(stats, cpu);
		do {
			seq = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
			pkts = cpu_stats->pkts;
			bytes = cpu_stats->bytes;
		} while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, seq));
		total.pkts += pkts;
		total.bytes += bytes;
	}
	nest = nla_nest_start(skb, NFTA_CHAIN_COUNTERS);
	if (nest == NULL)
		goto nla_put_failure;

	if (nla_put_be64(skb, NFTA_COUNTER_PACKETS, cpu_to_be64(total.pkts),
			 NFTA_COUNTER_PAD) ||
	    nla_put_be64(skb, NFTA_COUNTER_BYTES, cpu_to_be64(total.bytes),
			 NFTA_COUNTER_PAD))
		goto nla_put_failure;

	nla_nest_end(skb, nest);
	return 0;

nla_put_failure:
	return -ENOSPC;
}

static int nf_tables_fill_chain_info(struct sk_buff *skb, struct net *net,
				     u32 portid, u32 seq, int event, u32 flags,
				     int family, const struct nft_table *table,
				     const struct nft_chain *chain)
{
	struct nlmsghdr *nlh;
	struct nfgenmsg *nfmsg;

	event = nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event);
	nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct nfgenmsg), flags);
	if (nlh == NULL)
		goto nla_put_failure;

	nfmsg = nlmsg_data(nlh);
	nfmsg->nfgen_family	= family;
	nfmsg->version		= NFNETLINK_V0;
	nfmsg->res_id		= htons(net->nft.base_seq & 0xffff);

	if (nla_put_string(skb, NFTA_CHAIN_TABLE, table->name))
		goto nla_put_failure;
	if (nla_put_be64(skb, NFTA_CHAIN_HANDLE, cpu_to_be64(chain->handle),
			 NFTA_CHAIN_PAD))
		goto nla_put_failure;
	if (nla_put_string(skb, NFTA_CHAIN_NAME, chain->name))
		goto nla_put_failure;

	if (nft_is_base_chain(chain)) {
		const struct nft_base_chain *basechain = nft_base_chain(chain);
		const struct nf_hook_ops *ops = &basechain->ops;
		struct nft_stats __percpu *stats;
		struct nlattr *nest;

		nest = nla_nest_start(skb, NFTA_CHAIN_HOOK);
		if (nest == NULL)
			goto nla_put_failure;
		if (nla_put_be32(skb, NFTA_HOOK_HOOKNUM, htonl(ops->hooknum)))
			goto nla_put_failure;
		if (nla_put_be32(skb, NFTA_HOOK_PRIORITY, htonl(ops->priority)))
			goto nla_put_failure;
		if (basechain->dev_name[0] &&
		    nla_put_string(skb, NFTA_HOOK_DEV, basechain->dev_name))
			goto nla_put_failure;
		nla_nest_end(skb, nest);

		if (nla_put_be32(skb, NFTA_CHAIN_POLICY,
				 htonl(basechain->policy)))
			goto nla_put_failure;

		if (nla_put_string(skb, NFTA_CHAIN_TYPE, basechain->type->name))
			goto nla_put_failure;

		stats = rcu_dereference_check(basechain->stats,
					      lockdep_commit_lock_is_held(net));
		if (nft_dump_stats(skb, stats))
			goto nla_put_failure;
	}

	if (nla_put_be32(skb, NFTA_CHAIN_USE, htonl(chain->use)))
		goto nla_put_failure;

	nlmsg_end(skb, nlh);
	return 0;

nla_put_failure:
	nlmsg_trim(skb, nlh);
	return -1;
}

static void nf_tables_chain_notify(const struct nft_ctx *ctx, int event)
{
	struct sk_buff *skb;
	int err;

	if (!ctx->report &&
	    !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
		return;

	skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
	if (skb == NULL)
		goto err;

	err = nf_tables_fill_chain_info(skb, ctx->net, ctx->portid, ctx->seq,
					event, 0, ctx->family, ctx->table,
					ctx->chain);
	if (err < 0) {
		kfree_skb(skb);
		goto err;
	}

	nfnetlink_send(skb, ctx->net, ctx->portid, NFNLGRP_NFTABLES,
		       ctx->report, GFP_KERNEL);
	return;
err:
	nfnetlink_set_err(ctx->net, ctx->portid, NFNLGRP_NFTABLES, -ENOBUFS);
}

static int nf_tables_dump_chains(struct sk_buff *skb,
				 struct netlink_callback *cb)
{
	const struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh);
	const struct nft_table *table;
	const struct nft_chain *chain;
	unsigned int idx = 0, s_idx = cb->args[0];
	struct net *net = sock_net(skb->sk);
	int family = nfmsg->nfgen_family;

	rcu_read_lock();
	cb->seq = net->nft.base_seq;

	list_for_each_entry_rcu(table, &net->nft.tables, list) {
		if (family != NFPROTO_UNSPEC && family != table->family)
			continue;

		list_for_each_entry_rcu(chain, &table->chains, list) {
			if (idx < s_idx)
				goto cont;
			if (idx > s_idx)
				memset(&cb->args[1], 0,
				       sizeof(cb->args) - sizeof(cb->args[0]));
			if (!nft_is_active(net, chain))
				continue;
			if (nf_tables_fill_chain_info(skb, net,
						      NETLINK_CB(cb->skb).portid,
						      cb->nlh->nlmsg_seq,
						      NFT_MSG_NEWCHAIN,
						      NLM_F_MULTI,
						      table->family, table,
						      chain) < 0)
				goto done;

			nl_dump_check_consistent(cb, nlmsg_hdr(skb));
cont:
			idx++;
		}
	}
done:
	rcu_read_unlock();
	cb->args[0] = idx;
	return skb->len;
}

/* called with rcu_read_lock held */
static int nf_tables_getchain(struct net *net, struct sock *nlsk,
			      struct sk_buff *skb, const struct nlmsghdr *nlh,
			      const struct nlattr * const nla[],
			      struct netlink_ext_ack *extack)
{
	const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
	u8 genmask = nft_genmask_cur(net);
	const struct nft_chain *chain;
	struct nft_table *table;
	struct sk_buff *skb2;
	int family = nfmsg->nfgen_family;
	int err;

	if (nlh->nlmsg_flags & NLM_F_DUMP) {
		struct netlink_dump_control c = {
			.dump = nf_tables_dump_chains,
			.module = THIS_MODULE,
		};

		return nft_netlink_dump_start_rcu(nlsk, skb, nlh, &c);
	}

	table = nft_table_lookup(net, nla[NFTA_CHAIN_TABLE], family, genmask);
	if (IS_ERR(table)) {
		NL_SET_BAD_ATTR(extack, nla[NFTA_CHAIN_TABLE]);
		return PTR_ERR(table);
	}

	chain = nft_chain_lookup(net, table, nla[NFTA_CHAIN_NAME], genmask);
	if (IS_ERR(chain)) {
		NL_SET_BAD_ATTR(extack, nla[NFTA_CHAIN_NAME]);
		return PTR_ERR(chain);
	}

	skb2 = alloc_skb(NLMSG_GOODSIZE, GFP_ATOMIC);
	if (!skb2)
		return -ENOMEM;

	err = nf_tables_fill_chain_info(skb2, net, NETLINK_CB(skb).portid,
					nlh->nlmsg_seq, NFT_MSG_NEWCHAIN, 0,
					family, table, chain);
	if (err < 0)
		goto err;

	return nlmsg_unicast(nlsk, skb2, NETLINK_CB(skb).portid);

err:
	kfree_skb(skb2);
	return err;
}

static const struct nla_policy nft_counter_policy[NFTA_COUNTER_MAX + 1] = {
	[NFTA_COUNTER_PACKETS]	= { .type = NLA_U64 },
	[NFTA_COUNTER_BYTES]	= { .type = NLA_U64 },
};

static struct nft_stats __percpu *nft_stats_alloc(const struct nlattr *attr)
{
	struct nlattr *tb[NFTA_COUNTER_MAX+1];
	struct nft_stats __percpu *newstats;
	struct nft_stats *stats;
	int err;

	err = nla_parse_nested(tb, NFTA_COUNTER_MAX, attr, nft_counter_policy,
			       NULL);
	if (err < 0)
		return ERR_PTR(err);

	if (!tb[NFTA_COUNTER_BYTES] || !tb[NFTA_COUNTER_PACKETS])
		return ERR_PTR(-EINVAL);

	newstats = netdev_alloc_pcpu_stats(struct nft_stats);
	if (newstats == NULL)
		return ERR_PTR(-ENOMEM);

	/* Restore old counters on this cpu, no problem. Per-cpu statistics
	 * are not exposed to userspace.
	 */
	preempt_disable();
	stats = this_cpu_ptr(newstats);
	stats->bytes = be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_BYTES]));
	stats->pkts = be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_PACKETS]));
	preempt_enable();

	return newstats;
}

static void nft_chain_stats_replace(struct net *net,
				    struct nft_base_chain *chain,
				    struct nft_stats __percpu *newstats)
{
	struct nft_stats __percpu *oldstats;

	if (newstats == NULL)
		return;

	if (rcu_access_pointer(chain->stats)) {
		oldstats = rcu_dereference_protected(chain->stats,
					lockdep_commit_lock_is_held(net));
		rcu_assign_pointer(chain->stats, newstats);
		synchronize_rcu();
		free_percpu(oldstats);
	} else {
		rcu_assign_pointer(chain->stats, newstats);
		static_branch_inc(&nft_counters_enabled);
	}
}

static void nf_tables_chain_free_chain_rules(struct nft_chain *chain)
{
	struct nft_rule **g0 = rcu_dereference_raw(chain->rules_gen_0);
	struct nft_rule **g1 = rcu_dereference_raw(chain->rules_gen_1);

	if (g0 != g1)
		kvfree(g1);
	kvfree(g0);

	/* should be NULL either via abort or via successful commit */
	WARN_ON_ONCE(chain->rules_next);
	kvfree(chain->rules_next);
}

static void nf_tables_chain_destroy(struct nft_ctx *ctx)
{
	struct nft_chain *chain = ctx->chain;

	if (WARN_ON(chain->use > 0))
		return;

	/* no concurrent access possible anymore */
	nf_tables_chain_free_chain_rules(chain);

	if (nft_is_base_chain(chain)) {
		struct nft_base_chain *basechain = nft_base_chain(chain);

		module_put(basechain->type->owner);
		if (rcu_access_pointer(basechain->stats)) {
			static_branch_dec(&nft_counters_enabled);
			free_percpu(rcu_dereference_raw(basechain->stats));
		}
		kfree(chain->name);
		kfree(basechain);
	} else {
		kfree(chain->name);
		kfree(chain);
	}
}

struct nft_chain_hook {
	u32				num;
	s32				priority;
	const struct nft_chain_type	*type;
	struct net_device		*dev;
};

static int nft_chain_parse_hook(struct net *net,
				const struct nlattr * const nla[],
				struct nft_chain_hook *hook, u8 family,
				bool autoload)
{
	struct nlattr *ha[NFTA_HOOK_MAX + 1];
	const struct nft_chain_type *type;
	struct net_device *dev;
	int err;

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

	err = nla_parse_nested(ha, NFTA_HOOK_MAX, nla[NFTA_CHAIN_HOOK],
			       nft_hook_policy, NULL);
	if (err < 0)
		return err;

	if (ha[NFTA_HOOK_HOOKNUM] == NULL ||
	    ha[NFTA_HOOK_PRIORITY] == NULL)
		return -EINVAL;

	hook->num = ntohl(nla_get_be32(ha[NFTA_HOOK_HOOKNUM]));
	hook->priority = ntohl(nla_get_be32(ha[NFTA_HOOK_PRIORITY]));

	type = __nft_chain_type_get(family, NFT_CHAIN_T_DEFAULT);
	if (!type)
		return -EOPNOTSUPP;

	if (nla[NFTA_CHAIN_TYPE]) {
		type = nf_tables_chain_type_lookup(net, nla[NFTA_CHAIN_TYPE],
						   family, autoload);
		if (IS_ERR(type))
			return PTR_ERR(type);
	}
	if (hook->num > NF_MAX_HOOKS || !(type->hook_mask & (1 << hook->num)))
		return -EOPNOTSUPP;

	if (type->type == NFT_CHAIN_T_NAT &&
	    hook->priority <= NF_IP_PRI_CONNTRACK)
		return -EOPNOTSUPP;

	if (!try_module_get(type->owner))
		return -ENOENT;

	hook->type = type;

	hook->dev = NULL;
	if (family == NFPROTO_NETDEV) {
		char ifname[IFNAMSIZ];

		if (!ha[NFTA_HOOK_DEV]) {
			module_put(type->owner);
			return -EOPNOTSUPP;
		}

		nla_strlcpy(ifname, ha[NFTA_HOOK_DEV], IFNAMSIZ);
		dev = __dev_get_by_name(net, ifname);
		if (!dev) {
			module_put(type->owner);
			return -ENOENT;
		}
		hook->dev = dev;
	} else if (ha[NFTA_HOOK_DEV]) {
		module_put(type->owner);
		return -EOPNOTSUPP;
	}

	return 0;
}

static void nft_chain_release_hook(struct nft_chain_hook *hook)
{
	module_put(hook->type->owner);
}

struct nft_rules_old {
	struct rcu_head h;
	struct nft_rule **start;
};

static struct nft_rule **nf_tables_chain_alloc_rules(const struct nft_chain *chain,
						     unsigned int alloc)
{
	if (alloc > INT_MAX)
		return NULL;

	alloc += 1;	/* NULL, ends rules */
	if (sizeof(struct nft_rule *) > INT_MAX / alloc)
		return NULL;

	alloc *= sizeof(struct nft_rule *);
	alloc += sizeof(struct nft_rules_old);

	return kvmalloc(alloc, GFP_KERNEL);
}

static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
			      u8 policy)
{
	const struct nlattr * const *nla = ctx->nla;
	struct nft_table *table = ctx->table;
	struct nft_base_chain *basechain;
	struct nft_stats __percpu *stats;
	struct net *net = ctx->net;
	struct nft_chain *chain;
	struct nft_rule **rules;
	int err;

	if (table->use == UINT_MAX)
		return -EOVERFLOW;

	if (nla[NFTA_CHAIN_HOOK]) {
		struct nft_chain_hook hook;
		struct nf_hook_ops *ops;

		err = nft_chain_parse_hook(net, nla, &hook, family, true);
		if (err < 0)
			return err;

		basechain = kzalloc(sizeof(*basechain), GFP_KERNEL);
		if (basechain == NULL) {
			nft_chain_release_hook(&hook);
			return -ENOMEM;
		}

		if (hook.dev != NULL)
			strncpy(basechain->dev_name, hook.dev->name, IFNAMSIZ);

		if (nla[NFTA_CHAIN_COUNTERS]) {
			stats = nft_stats_alloc(nla[NFTA_CHAIN_COUNTERS]);
			if (IS_ERR(stats)) {
				nft_chain_release_hook(&hook);
				kfree(basechain);
				return PTR_ERR(stats);
			}
			rcu_assign_pointer(basechain->stats, stats);
			static_branch_inc(&nft_counters_enabled);
		}

		basechain->type = hook.type;
		chain = &basechain->chain;

		ops		= &basechain->ops;
		ops->pf		= family;
		ops->hooknum	= hook.num;
		ops->priority	= hook.priority;
		ops->priv	= chain;
		ops->hook	= hook.type->hooks[ops->hooknum];
		ops->dev	= hook.dev;

		chain->flags |= NFT_BASE_CHAIN;
		basechain->policy = policy;
	} else {
		chain = kzalloc(sizeof(*chain), GFP_KERNEL);
		if (chain == NULL)
			return -ENOMEM;
	}
	ctx->chain = chain;

	INIT_LIST_HEAD(&chain->rules);
	chain->handle = nf_tables_alloc_handle(table);
	chain->table = table;
	chain->name = nla_strdup(nla[NFTA_CHAIN_NAME], GFP_KERNEL);
	if (!chain->name) {
		err = -ENOMEM;
		goto err1;
	}

	rules = nf_tables_chain_alloc_rules(chain, 0);
	if (!rules) {
		err = -ENOMEM;
		goto err1;
	}

	*rules = NULL;
	rcu_assign_pointer(chain->rules_gen_0, rules);
	rcu_assign_pointer(chain->rules_gen_1, rules);

	err = nf_tables_register_hook(net, table, chain);
	if (err < 0)
		goto err1;

	err = rhltable_insert_key(&table->chains_ht, chain->name,
				  &chain->rhlhead, nft_chain_ht_params);
	if (err)
		goto err2;

	err = nft_trans_chain_add(ctx, NFT_MSG_NEWCHAIN);
	if (err < 0) {
		rhltable_remove(&table->chains_ht, &chain->rhlhead,
				nft_chain_ht_params);
		goto err2;
	}

	table->use++;
	list_add_tail_rcu(&chain->list, &table->chains);

	return 0;
err2:
	nf_tables_unregister_hook(net, table, chain);
err1:
	nf_tables_chain_destroy(ctx);

	return err;
}

static int nf_tables_updchain(struct nft_ctx *ctx, u8 genmask, u8 policy)
{
	const struct nlattr * const *nla = ctx->nla;
	struct nft_table *table = ctx->table;
	struct nft_chain *chain = ctx->chain;
	struct nft_base_chain *basechain;
	struct nft_stats *stats = NULL;
	struct nft_chain_hook hook;
	struct nf_hook_ops *ops;
	struct nft_trans *trans;
	int err;

	if (nla[NFTA_CHAIN_HOOK]) {
		if (!nft_is_base_chain(chain))
			return -EBUSY;

		err = nft_chain_parse_hook(ctx->net, nla, &hook, ctx->family,
					   false);
		if (err < 0)
			return err;

		basechain = nft_base_chain(chain);
		if (basechain->type != hook.type) {
			nft_chain_release_hook(&hook);
			return -EBUSY;
		}

		ops = &basechain->ops;
		if (ops->hooknum != hook.num ||
		    ops->priority != hook.priority ||
		    ops->dev != hook.dev) {
			nft_chain_release_hook(&hook);
			return -EBUSY;
		}
		nft_chain_release_hook(&hook);
	}

	if (nla[NFTA_CHAIN_HANDLE] &&
	    nla[NFTA_CHAIN_NAME]) {
		struct nft_chain *chain2;

		chain2 = nft_chain_lookup(ctx->net, table,
					  nla[NFTA_CHAIN_NAME], genmask);
		if (!IS_ERR(chain2))
			return -EEXIST;
	}

	if (nla[NFTA_CHAIN_COUNTERS]) {
		if (!nft_is_base_chain(chain))
			return -EOPNOTSUPP;

		stats = nft_stats_alloc(nla[NFTA_CHAIN_COUNTERS]);
		if (IS_ERR(stats))
			return PTR_ERR(stats);
	}

	err = -ENOMEM;
	trans = nft_trans_alloc(ctx, NFT_MSG_NEWCHAIN,
				sizeof(struct nft_trans_chain));
	if (trans == NULL)
		goto err;

	nft_trans_chain_stats(trans) = stats;
	nft_trans_chain_update(trans) = true;

	if (nla[NFTA_CHAIN_POLICY])
		nft_trans_chain_policy(trans) = policy;
	else
		nft_trans_chain_policy(trans) = -1;

	if (nla[NFTA_CHAIN_HANDLE] &&
	    nla[NFTA_CHAIN_NAME]) {
		struct nft_trans *tmp;
		char *name;

		err = -ENOMEM;
		name = nla_strdup(nla[NFTA_CHAIN_NAME], GFP_KERNEL);
		if (!name)
			goto err;

		err = -EEXIST;
		list_for_each_entry(tmp, &ctx->net->nft.commit_list, list) {
			if (tmp->msg_type == NFT_MSG_NEWCHAIN &&
			    tmp->ctx.table == table &&
			    nft_trans_chain_update(tmp) &&
			    nft_trans_chain_name(tmp) &&
			    strcmp(name, nft_trans_chain_name(tmp)) == 0) {
				kfree(name);
				goto err;
			}
		}

		nft_trans_chain_name(trans) = name;
	}
	list_add_tail(&trans->list, &ctx->net->nft.commit_list);

	return 0;
err:
	free_percpu(stats);
	kfree(trans);
	return err;
}

static int nf_tables_newchain(struct net *net, struct sock *nlsk,
			      struct sk_buff *skb, const struct nlmsghdr *nlh,
			      const struct nlattr * const nla[],
			      struct netlink_ext_ack *extack)
{
	const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
	u8 genmask = nft_genmask_next(net);
	int family = nfmsg->nfgen_family;
	const struct nlattr *attr;
	struct nft_table *table;
	struct nft_chain *chain;
	u8 policy = NF_ACCEPT;
	struct nft_ctx ctx;
	u64 handle = 0;

	lockdep_assert_held(&net->nft.commit_mutex);

	table = nft_table_lookup(net, nla[NFTA_CHAIN_TABLE], family, genmask);
	if (IS_ERR(table)) {
		NL_SET_BAD_ATTR(extack, nla[NFTA_CHAIN_TABLE]);
		return PTR_ERR(table);
	}

	chain = NULL;
	attr = nla[NFTA_CHAIN_NAME];

	if (nla[NFTA_CHAIN_HANDLE]) {
		handle = be64_to_cpu(nla_get_be64(nla[NFTA_CHAIN_HANDLE]));
		chain = nft_chain_lookup_byhandle(table, handle, genmask);
		if (IS_ERR(chain)) {
			NL_SET_BAD_ATTR(extack, nla[NFTA_CHAIN_HANDLE]);
			return PTR_ERR(chain);
		}
		attr = nla[NFTA_CHAIN_HANDLE];
	} else {
		chain = nft_chain_lookup(net, table, attr, genmask);
		if (IS_ERR(chain)) {
			if (PTR_ERR(chain) != -ENOENT) {
				NL_SET_BAD_ATTR(extack, attr);
				return PTR_ERR(chain);
			}
			chain = NULL;
		}
	}

	if (nla[NFTA_CHAIN_POLICY]) {
		if (chain != NULL &&
		    !nft_is_base_chain(chain)) {
			NL_SET_BAD_ATTR(extack, nla[NFTA_CHAIN_POLICY]);
			return -EOPNOTSUPP;
		}

		if (chain == NULL &&
		    nla[NFTA_CHAIN_HOOK] == NULL) {
			NL_SET_BAD_ATTR(extack, nla[NFTA_CHAIN_POLICY]);
			return -EOPNOTSUPP;
		}

		policy = ntohl(nla_get_be32(nla[NFTA_CHAIN_POLICY]));
		switch (policy) {
		case NF_DROP:
		case NF_ACCEPT:
			break;
		default:
			return -EINVAL;
		}
	}

	nft_ctx_init(&ctx, net, skb, nlh, family, table, chain, nla);

	if (chain != NULL) {
		if (nlh->nlmsg_flags & NLM_F_EXCL) {
			NL_SET_BAD_ATTR(extack, attr);
			return -EEXIST;
		}
		if (nlh->nlmsg_flags & NLM_F_REPLACE)
			return -EOPNOTSUPP;

		return nf_tables_updchain(&ctx, genmask, policy);
	}

	return nf_tables_addchain(&ctx, family, genmask, policy);
}

static int nf_tables_delchain(struct net *net, struct sock *nlsk,
			      struct sk_buff *skb, const struct nlmsghdr *nlh,
			      const struct nlattr * const nla[],
			      struct netlink_ext_ack *extack)
{
	const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
	u8 genmask = nft_genmask_next(net);
	int family = nfmsg->nfgen_family;
	const struct nlattr *attr;
	struct nft_table *table;
	struct nft_chain *chain;
	struct nft_rule *rule;
	struct nft_ctx ctx;
	u64 handle;
	u32 use;
	int err;

	table = nft_table_lookup(net, nla[NFTA_CHAIN_TABLE], family, genmask);
	if (IS_ERR(table)) {
		NL_SET_BAD_ATTR(extack, nla[NFTA_CHAIN_TABLE]);
		return PTR_ERR(table);
	}

	if (nla[NFTA_CHAIN_HANDLE]) {
		attr = nla[NFTA_CHAIN_HANDLE];
		handle = be64_to_cpu(nla_get_be64(attr));
		chain = nft_chain_lookup_byhandle(table, handle, genmask);
	} else {
		attr = nla[NFTA_CHAIN_NAME];
		chain = nft_chain_lookup(net, table, attr, genmask);
	}
	if (IS_ERR(chain)) {
		NL_SET_BAD_ATTR(extack, attr);
		return PTR_ERR(chain);
	}

	if (nlh->nlmsg_flags & NLM_F_NONREC &&
	    chain->use > 0)
		return -EBUSY;

	nft_ctx_init(&ctx, net, skb, nlh, family, table, chain, nla);

	use = chain->use;
	list_for_each_entry(rule, &chain->rules, list) {
		if (!nft_is_active_next(net, rule))
			continue;
		use--;

		err = nft_delrule(&ctx, rule);
		if (err < 0)
			return err;
	}

	/* There are rules and elements that are still holding references to us,
	 * we cannot do a recursive removal in this case.
	 */
	if (use > 0) {
		NL_SET_BAD_ATTR(extack, attr);
		return -EBUSY;
	}

	return nft_delchain(&ctx);
}

/*
 * Expressions
 */

/**
 *	nft_register_expr - register nf_tables expr type
 *	@ops: expr type
 *
 *	Registers the expr type for use with nf_tables. Returns zero on
 *	success or a negative errno code otherwise.
 */
int nft_register_expr(struct nft_expr_type *type)
{
	nfnl_lock(NFNL_SUBSYS_NFTABLES);
	if (type->family == NFPROTO_UNSPEC)
		list_add_tail_rcu(&type->list, &nf_tables_expressions);
	else
		list_add_rcu(&type->list, &nf_tables_expressions);
	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
	return 0;
}
EXPORT_SYMBOL_GPL(nft_register_expr);

/**
 *	nft_unregister_expr - unregister nf_tables expr type
 *	@ops: expr type
 *
 * 	Unregisters the expr typefor use with nf_tables.
 */
void nft_unregister_expr(struct nft_expr_type *type)
{
	nfnl_lock(NFNL_SUBSYS_NFTABLES);
	list_del_rcu(&type->list);
	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
}
EXPORT_SYMBOL_GPL(nft_unregister_expr);

static const struct nft_expr_type *__nft_expr_type_get(u8 family,
						       struct nlattr *nla)
{
	const struct nft_expr_type *type;

	list_for_each_entry(type, &nf_tables_expressions, list) {
		if (!nla_strcmp(nla, type->name) &&
		    (!type->family || type->family == family))
			return type;
	}
	return NULL;
}

static const struct nft_expr_type *nft_expr_type_get(struct net *net,
						     u8 family,
						     struct nlattr *nla)
{
	const struct nft_expr_type *type;

	if (nla == NULL)
		return ERR_PTR(-EINVAL);

	type = __nft_expr_type_get(family, nla);
	if (type != NULL && try_module_get(type->owner))
		return type;

	lockdep_nfnl_nft_mutex_not_held();
#ifdef CONFIG_MODULES
	if (type == NULL) {
		nft_request_module(net, "nft-expr-%u-%.*s", family,
				   nla_len(nla), (char *)nla_data(nla));
		if (__nft_expr_type_get(family, nla))
			return ERR_PTR(-EAGAIN);

		nft_request_module(net, "nft-expr-%.*s",
				   nla_len(nla), (char *)nla_data(nla));
		if (__nft_expr_type_get(family, nla))
			return ERR_PTR(-EAGAIN);
	}
#endif
	return ERR_PTR(-ENOENT);
}

static const struct nla_policy nft_expr_policy[NFTA_EXPR_MAX + 1] = {
	[NFTA_EXPR_NAME]	= { .type = NLA_STRING,
				    .len = NFT_MODULE_AUTOLOAD_LIMIT },
	[NFTA_EXPR_DATA]	= { .type = NLA_NESTED },
};

static int nf_tables_fill_expr_info(struct sk_buff *skb,
				    const struct nft_expr *expr)
{
	if (nla_put_string(skb, NFTA_EXPR_NAME, expr->ops->type->name))
		goto nla_put_failure;

	if (expr->ops->dump) {
		struct nlattr *data = nla_nest_start(skb, NFTA_EXPR_DATA);
		if (data == NULL)
			goto nla_put_failure;
		if (expr->ops->dump(skb, expr) < 0)
			goto nla_put_failure;
		nla_nest_end(skb, data);
	}

	return skb->len;

nla_put_failure:
	return -1;
};

int nft_expr_dump(struct sk_buff *skb, unsigned int attr,
		  const struct nft_expr *expr)
{
	struct nlattr *nest;

	nest = nla_nest_start(skb, attr);
	if (!nest)
		goto nla_put_failure;
	if (nf_tables_fill_expr_info(skb, expr) < 0)
		goto nla_put_failure;
	nla_nest_end(skb, nest);
	return 0;

nla_put_failure:
	return -1;
}

struct nft_expr_info {
	const struct nft_expr_ops	*ops;
	struct nlattr			*tb[NFT_EXPR_MAXATTR + 1];
};

static int nf_tables_expr_parse(const struct nft_ctx *ctx,
				const struct nlattr *nla,
				struct nft_expr_info *info)
{
	const struct nft_expr_type *type;
	const struct nft_expr_ops *ops;
	struct nlattr *tb[NFTA_EXPR_MAX + 1];
	int err;

	err = nla_parse_nested(tb, NFTA_EXPR_MAX, nla, nft_expr_policy, NULL);
	if (err < 0)
		return err;

	type = nft_expr_type_get(ctx->net, ctx->family, tb[NFTA_EXPR_NAME]);
	if (IS_ERR(type))
		return PTR_ERR(type);

	if (tb[NFTA_EXPR_DATA]) {
		err = nla_parse_nested(info->tb, type->maxattr,
				       tb[NFTA_EXPR_DATA], type->policy, NULL);
		if (err < 0)
			goto err1;
	} else
		memset(info->tb, 0, sizeof(info->tb[0]) * (type->maxattr + 1));

	if (type->select_ops != NULL) {
		ops = type->select_ops(ctx,
				       (const struct nlattr * const *)info->tb);
		if (IS_ERR(ops)) {
			err = PTR_ERR(ops);
			goto err1;
		}
	} else
		ops = type->ops;

	info->ops = ops;
	return 0;

err1:
	module_put(type->owner);
	return err;
}

static int nf_tables_newexpr(const struct nft_ctx *ctx,
			     const struct nft_expr_info *info,
			     struct nft_expr *expr)
{
	const struct nft_expr_ops *ops = info->ops;
	int err;

	expr->ops = ops;
	if (ops->init) {
		err = ops->init(ctx, expr, (const struct nlattr **)info->tb);
		if (err < 0)
			goto err1;
	}

	return 0;
err1:
	expr->ops = NULL;
	return err;
}

static void nf_tables_expr_destroy(const struct nft_ctx *ctx,
				   struct nft_expr *expr)
{
	const struct nft_expr_type *type = expr->ops->type;

	if (expr->ops->destroy)
		expr->ops->destroy(ctx, expr);
	module_put(type->owner);
}

struct nft_expr *nft_expr_init(const struct nft_ctx *ctx,
			       const struct nlattr *nla)
{
	struct nft_expr_info info;
	struct nft_expr *expr;
	struct module *owner;
	int err;

	err = nf_tables_expr_parse(ctx, nla, &info);
	if (err < 0)
		goto err1;

	err = -ENOMEM;
	expr = kzalloc(info.ops->size, GFP_KERNEL);
	if (expr == NULL)
		goto err2;

	err = nf_tables_newexpr(ctx, &info, expr);
	if (err < 0)
		goto err3;

	return expr;
err3:
	kfree(expr);
err2:
	owner = info.ops->type->owner;
	if (info.ops->type->release_ops)
		info.ops->type->release_ops(info.ops);

	module_put(owner);
err1:
	return ERR_PTR(err);
}

void nft_expr_destroy(const struct nft_ctx *ctx, struct nft_expr *expr)
{
	nf_tables_expr_destroy(ctx, expr);
	kfree(expr);
}

/*
 * Rules
 */

static struct nft_rule *__nft_rule_lookup(const struct nft_chain *chain,
					  u64 handle)
{
	struct nft_rule *rule;

	// FIXME: this sucks
	list_for_each_entry_rcu(rule, &chain->rules, list) {
		if (handle == rule->handle)
			return rule;
	}

	return ERR_PTR(-ENOENT);
}

static struct nft_rule *nft_rule_lookup(const struct nft_chain *chain,
					const struct nlattr *nla)
{
	if (nla == NULL)
		return ERR_PTR(-EINVAL);

	return __nft_rule_lookup(chain, be64_to_cpu(nla_get_be64(nla)));
}

static const struct nla_policy nft_rule_policy[NFTA_RULE_MAX + 1] = {
	[NFTA_RULE_TABLE]	= { .type = NLA_STRING,
				    .len = NFT_TABLE_MAXNAMELEN - 1 },
	[NFTA_RULE_CHAIN]	= { .type = NLA_STRING,
				    .len = NFT_CHAIN_MAXNAMELEN - 1 },
	[NFTA_RULE_HANDLE]	= { .type = NLA_U64 },
	[NFTA_RULE_EXPRESSIONS]	= { .type = NLA_NESTED },
	[NFTA_RULE_COMPAT]	= { .type = NLA_NESTED },
	[NFTA_RULE_POSITION]	= { .type = NLA_U64 },
	[NFTA_RULE_USERDATA]	= { .type = NLA_BINARY,
				    .len = NFT_USERDATA_MAXLEN },
	[NFTA_RULE_ID]		= { .type = NLA_U32 },
};

static int nf_tables_fill_rule_info(struct sk_buff *skb, struct net *net,
				    u32 portid, u32 seq, int event,
				    u32 flags, int family,
				    const struct nft_table *table,
				    const struct nft_chain *chain,
				    const struct nft_rule *rule)
{
	struct nlmsghdr *nlh;
	struct nfgenmsg *nfmsg;
	const struct nft_expr *expr, *next;
	struct nlattr *list;
	const struct nft_rule *prule;
	u16 type = nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event);

	nlh = nlmsg_put(skb, portid, seq, type, sizeof(struct nfgenmsg), flags);
	if (nlh == NULL)
		goto nla_put_failure;

	nfmsg = nlmsg_data(nlh);
	nfmsg->nfgen_family	= family;
	nfmsg->version		= NFNETLINK_V0;
	nfmsg->res_id		= htons(net->nft.base_seq & 0xffff);

	if (nla_put_string(skb, NFTA_RULE_TABLE, table->name))
		goto nla_put_failure;
	if (nla_put_string(skb, NFTA_RULE_CHAIN, chain->name))
		goto nla_put_failure;
	if (nla_put_be64(skb, NFTA_RULE_HANDLE, cpu_to_be64(rule->handle),
			 NFTA_RULE_PAD))
		goto nla_put_failure;

	if ((event != NFT_MSG_DELRULE) && (rule->list.prev != &chain->rules)) {
		prule = list_prev_entry(rule, list);
		if (nla_put_be64(skb, NFTA_RULE_POSITION,
				 cpu_to_be64(prule->handle),
				 NFTA_RULE_PAD))
			goto nla_put_failure;
	}

	list = nla_nest_start(skb, NFTA_RULE_EXPRESSIONS);
	if (list == NULL)
		goto nla_put_failure;
	nft_rule_for_each_expr(expr, next, rule) {
		if (nft_expr_dump(skb, NFTA_LIST_ELEM, expr) < 0)
			goto nla_put_failure;
	}
	nla_nest_end(skb, list);

	if (rule->udata) {
		struct nft_userdata *udata = nft_userdata(rule);
		if (nla_put(skb, NFTA_RULE_USERDATA, udata->len + 1,
			    udata->data) < 0)
			goto nla_put_failure;
	}

	nlmsg_end(skb, nlh);
	return 0;

nla_put_failure:
	nlmsg_trim(skb, nlh);
	return -1;
}

static void nf_tables_rule_notify(const struct nft_ctx *ctx,
				  const struct nft_rule *rule, int event)
{
	struct sk_buff *skb;
	int err;

	if (!ctx->report &&
	    !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
		return;

	skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
	if (skb == NULL)
		goto err;

	err = nf_tables_fill_rule_info(skb, ctx->net, ctx->portid, ctx->seq,
				       event, 0, ctx->family, ctx->table,
				       ctx->chain, rule);
	if (err < 0) {
		kfree_skb(skb);
		goto err;
	}

	nfnetlink_send(skb, ctx->net, ctx->portid, NFNLGRP_NFTABLES,
		       ctx->report, GFP_KERNEL);
	return;
err:
	nfnetlink_set_err(ctx->net, ctx->portid, NFNLGRP_NFTABLES, -ENOBUFS);
}

struct nft_rule_dump_ctx {
	char *table;
	char *chain;
};

static int nf_tables_dump_rules(struct sk_buff *skb,
				struct netlink_callback *cb)
{
	const struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh);
	const struct nft_rule_dump_ctx *ctx = cb->data;
	const struct nft_table *table;
	const struct nft_chain *chain;
	const struct nft_rule *rule;
	unsigned int idx = 0, s_idx = cb->args[0];
	struct net *net = sock_net(skb->sk);
	int family = nfmsg->nfgen_family;

	rcu_read_lock();
	cb->seq = net->nft.base_seq;

	list_for_each_entry_rcu(table, &net->nft.tables, list) {
		if (family != NFPROTO_UNSPEC && family != table->family)
			continue;

		if (ctx && ctx->table && strcmp(ctx->table, table->name) != 0)
			continue;

		list_for_each_entry_rcu(chain, &table->chains, list) {
			if (ctx && ctx->chain &&
			    strcmp(ctx->chain, chain->name) != 0)
				continue;

			list_for_each_entry_rcu(rule, &chain->rules, list) {
				if (!nft_is_active(net, rule))
					goto cont;
				if (idx < s_idx)
					goto cont;
				if (idx > s_idx)
					memset(&cb->args[1], 0,
					       sizeof(cb->args) - sizeof(cb->args[0]));
				if (nf_tables_fill_rule_info(skb, net, NETLINK_CB(cb->skb).portid,
							      cb->nlh->nlmsg_seq,
							      NFT_MSG_NEWRULE,
							      NLM_F_MULTI | NLM_F_APPEND,
							      table->family,
							      table, chain, rule) < 0)
					goto done;

				nl_dump_check_consistent(cb, nlmsg_hdr(skb));
cont:
				idx++;
			}
		}
	}
done:
	rcu_read_unlock();

	cb->args[0] = idx;
	return skb->len;
}

static int nf_tables_dump_rules_start(struct netlink_callback *cb)
{
	const struct nlattr * const *nla = cb->data;
	struct nft_rule_dump_ctx *ctx = NULL;

	if (nla[NFTA_RULE_TABLE] || nla[NFTA_RULE_CHAIN]) {
		ctx = kzalloc(sizeof(*ctx), GFP_ATOMIC);
		if (!ctx)
			return -ENOMEM;

		if (nla[NFTA_RULE_TABLE]) {
			ctx->table = nla_strdup(nla[NFTA_RULE_TABLE],
							GFP_ATOMIC);
			if (!ctx->table) {
				kfree(ctx);
				return -ENOMEM;
			}
		}
		if (nla[NFTA_RULE_CHAIN]) {
			ctx->chain = nla_strdup(nla[NFTA_RULE_CHAIN],
						GFP_ATOMIC);
			if (!ctx->chain) {
				kfree(ctx->table);
				kfree(ctx);
				return -ENOMEM;
			}
		}
	}

	cb->data = ctx;
	return 0;
}

static int nf_tables_dump_rules_done(struct netlink_callback *cb)
{
	struct nft_rule_dump_ctx *ctx = cb->data;

	if (ctx) {
		kfree(ctx->table);
		kfree(ctx->chain);
		kfree(ctx);
	}
	return 0;
}

/* called with rcu_read_lock held */
static int nf_tables_getrule(struct net *net, struct sock *nlsk,
			     struct sk_buff *skb, const struct nlmsghdr *nlh,
			     const struct nlattr * const nla[],
			     struct netlink_ext_ack *extack)
{
	const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
	u8 genmask = nft_genmask_cur(net);
	const struct nft_chain *chain;
	const struct nft_rule *rule;
	struct nft_table *table;
	struct sk_buff *skb2;
	int family = nfmsg->nfgen_family;
	int err;

	if (nlh->nlmsg_flags & NLM_F_DUMP) {
		struct netlink_dump_control c = {
			.start= nf_tables_dump_rules_start,
			.dump = nf_tables_dump_rules,
			.done = nf_tables_dump_rules_done,
			.module = THIS_MODULE,
			.data = (void *)nla,
		};

		return nft_netlink_dump_start_rcu(nlsk, skb, nlh, &c);
	}

	table = nft_table_lookup(net, nla[NFTA_RULE_TABLE], family, genmask);
	if (IS_ERR(table)) {
		NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_TABLE]);
		return PTR_ERR(table);
	}

	chain = nft_chain_lookup(net, table, nla[NFTA_RULE_CHAIN], genmask);
	if (IS_ERR(chain)) {
		NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_CHAIN]);
		return PTR_ERR(chain);
	}

	rule = nft_rule_lookup(chain, nla[NFTA_RULE_HANDLE]);
	if (IS_ERR(rule)) {
		NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_HANDLE]);
		return PTR_ERR(rule);
	}

	skb2 = alloc_skb(NLMSG_GOODSIZE, GFP_ATOMIC);
	if (!skb2)
		return -ENOMEM;

	err = nf_tables_fill_rule_info(skb2, net, NETLINK_CB(skb).portid,
				       nlh->nlmsg_seq, NFT_MSG_NEWRULE, 0,
				       family, table, chain, rule);
	if (err < 0)
		goto err;

	return nlmsg_unicast(nlsk, skb2, NETLINK_CB(skb).portid);

err:
	kfree_skb(skb2);
	return err;
}

static void nf_tables_rule_destroy(const struct nft_ctx *ctx,
				   struct nft_rule *rule)
{
	struct nft_expr *expr, *next;

	lockdep_assert_held(&ctx->net->nft.commit_mutex);
	/*
	 * Careful: some expressions might not be initialized in case this
	 * is called on error from nf_tables_newrule().
	 */
	expr = nft_expr_first(rule);
	while (expr != nft_expr_last(rule) && expr->ops) {
		next = nft_expr_next(expr);
		nf_tables_expr_destroy(ctx, expr);
		expr = next;
	}
	kfree(rule);
}

static void nf_tables_rule_release(const struct nft_ctx *ctx,
				   struct nft_rule *rule)
{
	nft_rule_expr_deactivate(ctx, rule, NFT_TRANS_RELEASE);
	nf_tables_rule_destroy(ctx, rule);
}

int nft_chain_validate(const struct nft_ctx *ctx, const struct nft_chain *chain)
{
	struct nft_expr *expr, *last;
	const struct nft_data *data;
	struct nft_rule *rule;
	int err;

	if (ctx->level == NFT_JUMP_STACK_SIZE)
		return -EMLINK;

	list_for_each_entry(rule, &chain->rules, list) {
		if (!nft_is_active_next(ctx->net, rule))
			continue;

		nft_rule_for_each_expr(expr, last, rule) {
			if (!expr->ops->validate)
				continue;

			err = expr->ops->validate(ctx, expr, &data);
			if (err < 0)
				return err;
		}
	}

	return 0;
}
EXPORT_SYMBOL_GPL(nft_chain_validate);

static int nft_table_validate(struct net *net, const struct nft_table *table)
{
	struct nft_chain *chain;
	struct nft_ctx ctx = {
		.net	= net,
		.family	= table->family,
	};
	int err;

	list_for_each_entry(chain, &table->chains, list) {
		if (!nft_is_base_chain(chain))
			continue;

		ctx.chain = chain;
		err = nft_chain_validate(&ctx, chain);
		if (err < 0)
			return err;
	}

	return 0;
}

#define NFT_RULE_MAXEXPRS	128

static int nf_tables_newrule(struct net *net, struct sock *nlsk,
			     struct sk_buff *skb, const struct nlmsghdr *nlh,
			     const struct nlattr * const nla[],
			     struct netlink_ext_ack *extack)
{
	const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
	u8 genmask = nft_genmask_next(net);
	struct nft_expr_info *info = NULL;
	int family = nfmsg->nfgen_family;
	struct nft_table *table;
	struct nft_chain *chain;
	struct nft_rule *rule, *old_rule = NULL;
	struct nft_userdata *udata;
	struct nft_trans *trans = NULL;
	struct nft_expr *expr;
	struct nft_ctx ctx;
	struct nlattr *tmp;
	unsigned int size, i, n, ulen = 0, usize = 0;
	int err, rem;
	u64 handle, pos_handle;

	lockdep_assert_held(&net->nft.commit_mutex);

	table = nft_table_lookup(net, nla[NFTA_RULE_TABLE], family, genmask);
	if (IS_ERR(table)) {
		NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_TABLE]);
		return PTR_ERR(table);
	}

	chain = nft_chain_lookup(net, table, nla[NFTA_RULE_CHAIN], genmask);
	if (IS_ERR(chain)) {
		NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_CHAIN]);
		return PTR_ERR(chain);
	}

	if (nla[NFTA_RULE_HANDLE]) {
		handle = be64_to_cpu(nla_get_be64(nla[NFTA_RULE_HANDLE]));
		rule = __nft_rule_lookup(chain, handle);
		if (IS_ERR(rule)) {
			NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_HANDLE]);
			return PTR_ERR(rule);
		}

		if (nlh->nlmsg_flags & NLM_F_EXCL) {
			NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_HANDLE]);
			return -EEXIST;
		}
		if (nlh->nlmsg_flags & NLM_F_REPLACE)
			old_rule = rule;
		else
			return -EOPNOTSUPP;
	} else {
		if (!(nlh->nlmsg_flags & NLM_F_CREATE) ||
		    nlh->nlmsg_flags & NLM_F_REPLACE)
			return -EINVAL;
		handle = nf_tables_alloc_handle(table);

		if (chain->use == UINT_MAX)
			return -EOVERFLOW;

		if (nla[NFTA_RULE_POSITION]) {
			pos_handle = be64_to_cpu(nla_get_be64(nla[NFTA_RULE_POSITION]));
			old_rule = __nft_rule_lookup(chain, pos_handle);
			if (IS_ERR(old_rule)) {
				NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_POSITION]);
				return PTR_ERR(old_rule);
			}
		}
	}

	nft_ctx_init(&ctx, net, skb, nlh, family, table, chain, nla);

	n = 0;
	size = 0;
	if (nla[NFTA_RULE_EXPRESSIONS]) {
		info = kvmalloc_array(NFT_RULE_MAXEXPRS,
				      sizeof(struct nft_expr_info),
				      GFP_KERNEL);
		if (!info)
			return -ENOMEM;

		nla_for_each_nested(tmp, nla[NFTA_RULE_EXPRESSIONS], rem) {
			err = -EINVAL;
			if (nla_type(tmp) != NFTA_LIST_ELEM)
				goto err1;
			if (n == NFT_RULE_MAXEXPRS)
				goto err1;
			err = nf_tables_expr_parse(&ctx, tmp, &info[n]);
			if (err < 0)
				goto err1;
			size += info[n].ops->size;
			n++;
		}
	}
	/* Check for overflow of dlen field */
	err = -EFBIG;
	if (size >= 1 << 12)
		goto err1;

	if (nla[NFTA_RULE_USERDATA]) {
		ulen = nla_len(nla[NFTA_RULE_USERDATA]);
		if (ulen > 0)
			usize = sizeof(struct nft_userdata) + ulen;
	}

	err = -ENOMEM;
	rule = kzalloc(sizeof(*rule) + size + usize, GFP_KERNEL);
	if (rule == NULL)
		goto err1;

	nft_activate_next(net, rule);

	rule->handle = handle;
	rule->dlen   = size;
	rule->udata  = ulen ? 1 : 0;

	if (ulen) {
		udata = nft_userdata(rule);
		udata->len = ulen - 1;
		nla_memcpy(udata->data, nla[NFTA_RULE_USERDATA], ulen);
	}

	expr = nft_expr_first(rule);
	for (i = 0; i < n; i++) {
		err = nf_tables_newexpr(&ctx, &info[i], expr);
		if (err < 0)
			goto err2;

		if (info[i].ops->validate)
			nft_validate_state_update(net, NFT_VALIDATE_NEED);

		info[i].ops = NULL;
		expr = nft_expr_next(expr);
	}

	if (nlh->nlmsg_flags & NLM_F_REPLACE) {
		trans = nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule);
		if (trans == NULL) {
			err = -ENOMEM;
			goto err2;
		}
		err = nft_delrule(&ctx, old_rule);
		if (err < 0) {
			nft_trans_destroy(trans);
			goto err2;
		}

		list_add_tail_rcu(&rule->list, &old_rule->list);
	} else {
		if (nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule) == NULL) {
			err = -ENOMEM;
			goto err2;
		}

		if (nlh->nlmsg_flags & NLM_F_APPEND) {
			if (old_rule)
				list_add_rcu(&rule->list, &old_rule->list);
			else
				list_add_tail_rcu(&rule->list, &chain->rules);
		 } else {
			if (old_rule)
				list_add_tail_rcu(&rule->list, &old_rule->list);
			else
				list_add_rcu(&rule->list, &chain->rules);
		}
	}
	kvfree(info);
	chain->use++;

	if (net->nft.validate_state == NFT_VALIDATE_DO)
		return nft_table_validate(net, table);

	return 0;
err2:
	nf_tables_rule_release(&ctx, rule);
err1:
	for (i = 0; i < n; i++) {
		if (info[i].ops) {
			module_put(info[i].ops->type->owner);
			if (info[i].ops->type->release_ops)
				info[i].ops->type->release_ops(info[i].ops);
		}
	}
	kvfree(info);
	return err;
}

static struct nft_rule *nft_rule_lookup_byid(const struct net *net,
					     const struct nlattr *nla)
{
	u32 id = ntohl(nla_get_be32(nla));
	struct nft_trans *trans;

	list_for_each_entry(trans, &net->nft.commit_list, list) {
		struct nft_rule *rule = nft_trans_rule(trans);

		if (trans->msg_type == NFT_MSG_NEWRULE &&
		    id == nft_trans_rule_id(trans))
			return rule;
	}
	return ERR_PTR(-ENOENT);
}

static int nf_tables_delrule(struct net *net, struct sock *nlsk,
			     struct sk_buff *skb, const struct nlmsghdr *nlh,
			     const struct nlattr * const nla[],
			     struct netlink_ext_ack *extack)
{
	const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
	u8 genmask = nft_genmask_next(net);
	struct nft_table *table;
	struct nft_chain *chain = NULL;
	struct nft_rule *rule;
	int family = nfmsg->nfgen_family, err = 0;
	struct nft_ctx ctx;

	table = nft_table_lookup(net, nla[NFTA_RULE_TABLE], family, genmask);
	if (IS_ERR(table)) {
		NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_TABLE]);
		return PTR_ERR(table);
	}

	if (nla[NFTA_RULE_CHAIN]) {
		chain = nft_chain_lookup(net, table, nla[NFTA_RULE_CHAIN],
					 genmask);
		if (IS_ERR(chain)) {
			NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_CHAIN]);
			return PTR_ERR(chain);
		}
	}

	nft_ctx_init(&ctx, net, skb, nlh, family, table, chain, nla);

	if (chain) {
		if (nla[NFTA_RULE_HANDLE]) {
			rule = nft_rule_lookup(chain, nla[NFTA_RULE_HANDLE]);
			if (IS_ERR(rule)) {
				NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_HANDLE]);
				return PTR_ERR(rule);
			}

			err = nft_delrule(&ctx, rule);
		} else if (nla[NFTA_RULE_ID]) {
			rule = nft_rule_lookup_byid(net, nla[NFTA_RULE_ID]);
			if (IS_ERR(rule)) {
				NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_ID]);
				return PTR_ERR(rule);
			}

			err = nft_delrule(&ctx, rule);
		} else {
			err = nft_delrule_by_chain(&ctx);
		}
	} else {
		list_for_each_entry(chain, &table->chains, list) {
			if (!nft_is_active_next(net, chain))
				continue;

			ctx.chain = chain;
			err = nft_delrule_by_chain(&ctx);
			if (err < 0)
				break;
		}
	}

	return err;
}

/*
 * Sets
 */

static LIST_HEAD(nf_tables_set_types);

int nft_register_set(struct nft_set_type *type)
{
	nfnl_lock(NFNL_SUBSYS_NFTABLES);
	list_add_tail_rcu(&type->list, &nf_tables_set_types);
	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
	return 0;
}
EXPORT_SYMBOL_GPL(nft_register_set);

void nft_unregister_set(struct nft_set_type *type)
{
	nfnl_lock(NFNL_SUBSYS_NFTABLES);
	list_del_rcu(&type->list);
	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
}
EXPORT_SYMBOL_GPL(nft_unregister_set);

#define NFT_SET_FEATURES	(NFT_SET_INTERVAL | NFT_SET_MAP | \
				 NFT_SET_TIMEOUT | NFT_SET_OBJECT | \
				 NFT_SET_EVAL)

static bool nft_set_ops_candidate(const struct nft_set_type *type, u32 flags)
{
	return (flags & type->features) == (flags & NFT_SET_FEATURES);
}

/*
 * Select a set implementation based on the data characteristics and the
 * given policy. The total memory use might not be known if no size is
 * given, in that case the amount of memory per element is used.
 */
static const struct nft_set_ops *
nft_select_set_ops(const struct nft_ctx *ctx,
		   const struct nlattr * const nla[],
		   const struct nft_set_desc *desc,
		   enum nft_set_policies policy)
{
	const struct nft_set_ops *ops, *bops;
	struct nft_set_estimate est, best;
	const struct nft_set_type *type;
	u32 flags = 0;

	lockdep_assert_held(&ctx->net->nft.commit_mutex);
	lockdep_nfnl_nft_mutex_not_held();
#ifdef CONFIG_MODULES
	if (list_empty(&nf_tables_set_types)) {
		nft_request_module(ctx->net, "nft-set");
		if (!list_empty(&nf_tables_set_types))
			return ERR_PTR(-EAGAIN);
	}
#endif
	if (nla[NFTA_SET_FLAGS] != NULL)
		flags = ntohl(nla_get_be32(nla[NFTA_SET_FLAGS]));

	bops	    = NULL;
	best.size   = ~0;
	best.lookup = ~0;
	best.space  = ~0;

	list_for_each_entry(type, &nf_tables_set_types, list) {
		ops = &type->ops;

		if (!nft_set_ops_candidate(type, flags))
			continue;
		if (!ops->estimate(desc, flags, &est))
			continue;

		switch (policy) {
		case NFT_SET_POL_PERFORMANCE:
			if (est.lookup < best.lookup)
				break;
			if (est.lookup == best.lookup &&
			    est.space < best.space)
				break;
			continue;
		case NFT_SET_POL_MEMORY:
			if (!desc->size) {
				if (est.space < best.space)
					break;
				if (est.space == best.space &&
				    est.lookup < best.lookup)
					break;
			} else if (est.size < best.size || !bops) {
				break;
			}
			continue;
		default:
			break;
		}

		if (!try_module_get(type->owner))
			continue;
		if (bops != NULL)
			module_put(to_set_type(bops)->owner);