/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/kernel.h>
#include <linux/slab.h>
#include <net/flow_offload.h>
#include <linux/rtnetlink.h>
#include <linux/mutex.h>
#include <linux/rhashtable.h>

struct flow_rule *flow_rule_alloc(unsigned int num_actions)
{
	struct flow_rule *rule;
	int i;

	rule = kzalloc(struct_size(rule, action.entries, num_actions),
		       GFP_KERNEL);
	if (!rule)
		return NULL;

	rule->action.num_entries = num_actions;
	/* Pre-fill each action hw_stats with DONT_CARE.
	 * Caller can override this if it wants stats for a given action.
	 */
	for (i = 0; i < num_actions; i++)
		rule->action.entries[i].hw_stats = FLOW_ACTION_HW_STATS_DONT_CARE;

	return rule;
}
EXPORT_SYMBOL(flow_rule_alloc);

#define FLOW_DISSECTOR_MATCH(__rule, __type, __out)				\
	const struct flow_match *__m = &(__rule)->match;			\
	struct flow_dissector *__d = (__m)->dissector;				\
										\
	(__out)->key = skb_flow_dissector_target(__d, __type, (__m)->key);	\
	(__out)->mask = skb_flow_dissector_target(__d, __type, (__m)->mask);	\

void flow_rule_match_meta(const struct flow_rule *rule,
			  struct flow_match_meta *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_META, out);
}
EXPORT_SYMBOL(flow_rule_match_meta);

void flow_rule_match_basic(const struct flow_rule *rule,
			   struct flow_match_basic *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_BASIC, out);
}
EXPORT_SYMBOL(flow_rule_match_basic);

void flow_rule_match_control(const struct flow_rule *rule,
			     struct flow_match_control *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_CONTROL, out);
}
EXPORT_SYMBOL(flow_rule_match_control);

void flow_rule_match_eth_addrs(const struct flow_rule *rule,
			       struct flow_match_eth_addrs *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ETH_ADDRS, out);
}
EXPORT_SYMBOL(flow_rule_match_eth_addrs);

void flow_rule_match_vlan(const struct flow_rule *rule,
			  struct flow_match_vlan *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_VLAN, out);
}
EXPORT_SYMBOL(flow_rule_match_vlan);

void flow_rule_match_cvlan(const struct flow_rule *rule,
			   struct flow_match_vlan *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_CVLAN, out);
}
EXPORT_SYMBOL(flow_rule_match_cvlan);

void flow_rule_match_ipv4_addrs(const struct flow_rule *rule,
				struct flow_match_ipv4_addrs *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_IPV4_ADDRS, out);
}
EXPORT_SYMBOL(flow_rule_match_ipv4_addrs);

void flow_rule_match_ipv6_addrs(const struct flow_rule *rule,
				struct flow_match_ipv6_addrs *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_IPV6_ADDRS, out);
}
EXPORT_SYMBOL(flow_rule_match_ipv6_addrs);

void flow_rule_match_ip(const struct flow_rule *rule,
			struct flow_match_ip *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_IP, out);
}
EXPORT_SYMBOL(flow_rule_match_ip);

void flow_rule_match_ports(const struct flow_rule *rule,
			   struct flow_match_ports *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_PORTS, out);
}
EXPORT_SYMBOL(flow_rule_match_ports);

void flow_rule_match_tcp(const struct flow_rule *rule,
			 struct flow_match_tcp *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_TCP, out);
}
EXPORT_SYMBOL(flow_rule_match_tcp);

void flow_rule_match_icmp(const struct flow_rule *rule,
			  struct flow_match_icmp *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ICMP, out);
}
EXPORT_SYMBOL(flow_rule_match_icmp);

void flow_rule_match_mpls(const struct flow_rule *rule,
			  struct flow_match_mpls *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_MPLS, out);
}
EXPORT_SYMBOL(flow_rule_match_mpls);

void flow_rule_match_enc_control(const struct flow_rule *rule,
				 struct flow_match_control *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_CONTROL, out);
}
EXPORT_SYMBOL(flow_rule_match_enc_control);

void flow_rule_match_enc_ipv4_addrs(const struct flow_rule *rule,
				    struct flow_match_ipv4_addrs *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS, out);
}
EXPORT_SYMBOL(flow_rule_match_enc_ipv4_addrs);

void flow_rule_match_enc_ipv6_addrs(const struct flow_rule *rule,
				    struct flow_match_ipv6_addrs *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS, out);
}
EXPORT_SYMBOL(flow_rule_match_enc_ipv6_addrs);

void flow_rule_match_enc_ip(const struct flow_rule *rule,
			    struct flow_match_ip *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_IP, out);
}
EXPORT_SYMBOL(flow_rule_match_enc_ip);

void flow_rule_match_enc_ports(const struct flow_rule *rule,
			       struct flow_match_ports *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_PORTS, out);
}
EXPORT_SYMBOL(flow_rule_match_enc_ports);

void flow_rule_match_enc_keyid(const struct flow_rule *rule,
			       struct flow_match_enc_keyid *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_KEYID, out);
}
EXPORT_SYMBOL(flow_rule_match_enc_keyid);

void flow_rule_match_enc_opts(const struct flow_rule *rule,
			      struct flow_match_enc_opts *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_OPTS, out);
}
EXPORT_SYMBOL(flow_rule_match_enc_opts);

struct flow_action_cookie *flow_action_cookie_create(void *data,
						     unsigned int len,
						     gfp_t gfp)
{
	struct flow_action_cookie *cookie;

	cookie = kmalloc(sizeof(*cookie) + len, gfp);
	if (!cookie)
		return NULL;
	cookie->cookie_len = len;
	memcpy(cookie->cookie, data, len);
	return cookie;
}
EXPORT_SYMBOL(flow_action_cookie_create);

void flow_action_cookie_destroy(struct flow_action_cookie *cookie)
{
	kfree(cookie);
}
EXPORT_SYMBOL(flow_action_cookie_destroy);

void flow_rule_match_ct(const struct flow_rule *rule,
			struct flow_match_ct *out)
{
	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_CT, out);
}
EXPORT_SYMBOL(flow_rule_match_ct);

struct flow_block_cb *flow_block_cb_alloc(flow_setup_cb_t *cb,
					  void *cb_ident, void *cb_priv,
					  void (*release)(void *cb_priv))
{
	struct flow_block_cb *block_cb;

	block_cb = kzalloc(sizeof(*block_cb), GFP_KERNEL);
	if (!block_cb)
		return ERR_PTR(-ENOMEM);

	block_cb->cb = cb;
	block_cb->cb_ident = cb_ident;
	block_cb->cb_priv = cb_priv;
	block_cb->release = release;

	return block_cb;
}
EXPORT_SYMBOL(flow_block_cb_alloc);

void flow_block_cb_free(struct flow_block_cb *block_cb)
{
	if (block_cb->release)
		block_cb->release(block_cb->cb_priv);

	kfree(block_cb);
}
EXPORT_SYMBOL(flow_block_cb_free);

struct flow_block_cb *flow_block_cb_lookup(struct flow_block *block,
					   flow_setup_cb_t *cb, void *cb_ident)
{
	struct flow_block_cb *block_cb;

	list_for_each_entry(block_cb, &block->cb_list, list) {
		if (block_cb->cb == cb &&
		    block_cb->cb_ident == cb_ident)
			return block_cb;
	}

	return NULL;
}
EXPORT_SYMBOL(flow_block_cb_lookup);

void *flow_block_cb_priv(struct flow_block_cb *block_cb)
{
	return block_cb->cb_priv;
}
EXPORT_SYMBOL(flow_block_cb_priv);

void flow_block_cb_incref(struct flow_block_cb *block_cb)
{
	block_cb->refcnt++;
}
EXPORT_SYMBOL(flow_block_cb_incref);

unsigned int flow_block_cb_decref(struct flow_block_cb *block_cb)
{
	return --block_cb->refcnt;
}
EXPORT_SYMBOL(flow_block_cb_decref);

bool flow_block_cb_is_busy(flow_setup_cb_t *cb, void *cb_ident,
			   struct list_head *driver_block_list)
{
	struct flow_block_cb *block_cb;

	list_for_each_entry(block_cb, driver_block_list, driver_list) {
		if (block_cb->cb == cb &&
		    block_cb->cb_ident == cb_ident)
			return true;
	}

	return false;
}
EXPORT_SYMBOL(flow_block_cb_is_busy);

int flow_block_cb_setup_simple(struct flow_block_offload *f,
			       struct list_head *driver_block_list,
			       flow_setup_cb_t *cb,
			       void *cb_ident, void *cb_priv,
			       bool ingress_only)
{
	struct flow_block_cb *block_cb;

	if (ingress_only &&
	    f->binder_type != FLOW_BLOCK_BINDER_TYPE_CLSACT_INGRESS)
		return -EOPNOTSUPP;

	f->driver_block_list = driver_block_list;

	switch (f->command) {
	case FLOW_BLOCK_BIND:
		if (flow_block_cb_is_busy(cb, cb_ident, driver_block_list))
			return -EBUSY;

		block_cb = flow_block_cb_alloc(cb, cb_ident, cb_priv, NULL);
		if (IS_ERR(block_cb))
			return PTR_ERR(block_cb);

		flow_block_cb_add(block_cb, f);
		list_add_tail(&block_cb->driver_list, driver_block_list);
		return 0;
	case FLOW_BLOCK_UNBIND:
		block_cb = flow_block_cb_lookup(f->block, cb, cb_ident);
		if (!block_cb)
			return -ENOENT;

		flow_block_cb_remove(block_cb, f);
		list_del(&block_cb->driver_list);
		return 0;
	default:
		return -EOPNOTSUPP;
	}
}
EXPORT_SYMBOL(flow_block_cb_setup_simple);

static DEFINE_MUTEX(flow_indr_block_lock);
static LIST_HEAD(flow_block_indr_list);
static LIST_HEAD(flow_block_indr_dev_list);
static LIST_HEAD(flow_indir_dev_list);

struct flow_indr_dev {
	struct list_head		list;
	flow_indr_block_bind_cb_t	*cb;
	void				*cb_priv;
	refcount_t			refcnt;
	struct rcu_head			rcu;
};

static struct flow_indr_dev *flow_indr_dev_alloc(flow_indr_block_bind_cb_t *cb,
						 void *cb_priv)
{
	struct flow_indr_dev *indr_dev;

	indr_dev = kmalloc(sizeof(*indr_dev), GFP_KERNEL);
	if (!indr_dev)
		return NULL;

	indr_dev->cb		= cb;
	indr_dev->cb_priv	= cb_priv;
	refcount_set(&indr_dev->refcnt, 1);

	return indr_dev;
}

struct flow_indir_dev_info {
	void *data;
	struct net_device *dev;
	struct Qdisc *sch;
	enum tc_setup_type type;
	void (*cleanup)(struct flow_block_cb *block_cb);
	struct list_head list;
	enum flow_block_command command;
	enum flow_block_binder_type binder_type;
	struct list_head *cb_list;
};

static void existing_qdiscs_register(flow_indr_block_bind_cb_t *cb, void *cb_priv)
{
	struct flow_block_offload bo;
	struct flow_indir_dev_info *cur;

	list_for_each_entry(cur, &flow_indir_dev_list, list) {
		memset(&bo, 0, sizeof(bo));
		bo.command = cur->command;
		bo.binder_type = cur->binder_type;
		INIT_LIST_HEAD(&bo.cb_list);
		cb(cur->dev, cur->sch, cb_priv, cur->type, &bo, cur->data, cur->cleanup);
		list_splice(&bo.cb_list, cur->cb_list);
	}
}

int flow_indr_dev_register(flow_indr_block_bind_cb_t *cb, void *cb_priv)
{
	struct flow_indr_dev *indr_dev;

	mutex_lock(&flow_indr_block_lock);
	list_for_each_entry(indr_dev, &flow_block_indr_dev_list, list) {
		if (indr_dev->cb == cb &&
		    indr_dev->cb_priv == cb_priv) {
			refcount_inc(&indr_dev->refcnt);
			mutex_unlock(&flow_indr_block_lock);
			return 0;
		}
	}

	indr_dev = flow_indr_dev_alloc(cb, cb_priv);
	if (!indr_dev) {
		mutex_unlock(&flow_indr_block_lock);
		return -ENOMEM;
	}

	list_add(&indr_dev->list, &flow_block_indr_dev_list);
	existing_qdiscs_register(cb, cb_priv);
	mutex_unlock(&flow_indr_block_lock);

	return 0;
}
EXPORT_SYMBOL(flow_indr_dev_register);

static void __flow_block_indr_cleanup(void (*release)(void *cb_priv),
				      void *cb_priv,
				      struct list_head *cleanup_list)
{
	struct flow_block_cb *this, *next;

	list_for_each_entry_safe(this, next, &flow_block_indr_list, indr.list) {
		if (this->release == release &&
		    this->indr.cb_priv == cb_priv)
			list_move(&this->indr.list, cleanup_list);
	}
}

static void flow_block_indr_notify(struct list_head *cleanup_list)
{
	struct flow_block_cb *this, *next;

	list_for_each_entry_safe(this, next, cleanup_list, indr.list) {
		list_del(&this->indr.list);
		this->indr.cleanup(this);
	}
}

void flow_indr_dev_unregister(flow_indr_block_bind_cb_t *cb, void *cb_priv,
			      void (*release)(void *cb_priv))
{
	struct flow_indr_dev *this, *next, *indr_dev = NULL;
	LIST_HEAD(cleanup_list);

	mutex_lock(&flow_indr_block_lock);
	list_for_each_entry_safe(this, next, &flow_block_indr_dev_list, list) {
		if (this->cb == cb &&
		    this->cb_priv == cb_priv &&
		    refcount_dec_and_test(&this->refcnt)) {
			indr_dev = this;
			list_del(&indr_dev->list);
			break;
		}
	}

	if (!indr_dev) {
		mutex_unlock(&flow_indr_block_lock);
		return;
	}

	__flow_block_indr_cleanup(release, cb_priv, &cleanup_list);
	mutex_unlock(&flow_indr_block_lock);

	flow_block_indr_notify(&cleanup_list);
	kfree(indr_dev);
}
EXPORT_SYMBOL(flow_indr_dev_unregister);

static void flow_block_indr_init(struct flow_block_cb *flow_block,
				 struct flow_block_offload *bo,
				 struct net_device *dev, struct Qdisc *sch, void *data,
				 void *cb_priv,
				 void (*cleanup)(struct flow_block_cb *block_cb))
{
	flow_block->indr.binder_type = bo->binder_type;
	flow_block->indr.data = data;
	flow_block->indr.cb_priv = cb_priv;
	flow_block->indr.dev = dev;
	flow_block->indr.sch = sch;
	flow_block->indr.cleanup = cleanup;
}

struct flow_block_cb *flow_indr_block_cb_alloc(flow_setup_cb_t *cb,
					       void *cb_ident, void *cb_priv,
					       void (*release)(void *cb_priv),
					       struct flow_block_offload *bo,
					       struct net_device *dev,
					       struct Qdisc *sch, void *data,
					       void *indr_cb_priv,
					       void (*cleanup)(struct flow_block_cb *block_cb))
{
	struct flow_block_cb *block_cb;

	block_cb = flow_block_cb_alloc(cb, cb_ident, cb_priv, release);
	if (IS_ERR(block_cb))
		goto out;

	flow_block_indr_init(block_cb, bo, dev, sch, data, indr_cb_priv, cleanup);
	list_add(&block_cb->indr.list, &flow_block_indr_list);

out:
	return block_cb;
}
EXPORT_SYMBOL(flow_indr_block_cb_alloc);

static struct flow_indir_dev_info *find_indir_dev(void *data)
{
	struct flow_indir_dev_info *cur;

	list_for_each_entry(cur, &flow_indir_dev_list, list) {
		if (cur->data == data)
			return cur;
	}
	return NULL;
}

static int indir_dev_add(void *data, struct net_device *dev, struct Qdisc *sch,
			 enum tc_setup_type type, void (*cleanup)(struct flow_block_cb *block_cb),
			 struct flow_block_offload *bo)
{
	struct flow_indir_dev_info *info;

	info = find_indir_dev(data);
	if (info)
		return -EEXIST;

	info = kzalloc(sizeof(*info), GFP_KERNEL);
	if (!info)
		return -ENOMEM;

	info->data = data;
	info->dev = dev;
	info->sch = sch;
	info->type = type;
	info->cleanup = cleanup;
	info->command = bo->command;
	info->binder_type = bo->binder_type;
	info->cb_list = bo->cb_list_head;

	list_add(&info->list, &flow_indir_dev_list);
	return 0;
}

static int indir_dev_remove(void *data)
{
	struct flow_indir_dev_info *info;

	info = find_indir_dev(data);
	if (!info)
		return -ENOENT;

	list_del(&info->list);

	kfree(info);
	return 0;
}

int flow_indr_dev_setup_offload(struct net_device *dev,	struct Qdisc *sch,
				enum tc_setup_type type, void *data,
				struct flow_block_offload *bo,
				void (*cleanup)(struct flow_block_cb *block_cb))
{
	struct flow_indr_dev *this;

	mutex_lock(&flow_indr_block_lock);

	if (bo->command == FLOW_BLOCK_BIND)
		indir_dev_add(data, dev, sch, type, cleanup, bo);
	else if (bo->command == FLOW_BLOCK_UNBIND)
		indir_dev_remove(data);

	list_for_each_entry(this, &flow_block_indr_dev_list, list)
		this->cb(dev, sch, this->cb_priv, type, bo, data, cleanup);

	mutex_unlock(&flow_indr_block_lock);

	return list_empty(&bo->cb_list) ? -EOPNOTSUPP : 0;
}
EXPORT_SYMBOL(flow_indr_dev_setup_offload);

bool flow_indr_dev_exists(void)
{
	return !list_empty(&flow_block_indr_dev_list);
}
EXPORT_SYMBOL(flow_indr_dev_exists);
