hci_request.c

/*
   BlueZ - Bluetooth protocol stack for Linux

   Copyright (C) 2014 Intel Corporation

   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;

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
   IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
   CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
   WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

   ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
   COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
   SOFTWARE IS DISCLAIMED.
*/

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include <net/bluetooth/mgmt.h>

#include "smp.h"
#include "hci_request.h"

#define HCI_REQ_DONE	  0
#define HCI_REQ_PEND	  1
#define HCI_REQ_CANCELED  2

void hci_req_init(struct hci_request *req, struct hci_dev *hdev)
{
	skb_queue_head_init(&req->cmd_q);
	req->hdev = hdev;
	req->err = 0;
}

static int req_run(struct hci_request *req, hci_req_complete_t complete,
		   hci_req_complete_skb_t complete_skb)
{
	struct hci_dev *hdev = req->hdev;
	struct sk_buff *skb;
	unsigned long flags;

	BT_DBG("length %u", skb_queue_len(&req->cmd_q));

	/* If an error occurred during request building, remove all HCI
	 * commands queued on the HCI request queue.
	 */
	if (req->err) {
		skb_queue_purge(&req->cmd_q);
		return req->err;
	}

	/* Do not allow empty requests */
	if (skb_queue_empty(&req->cmd_q))
		return -ENODATA;

	skb = skb_peek_tail(&req->cmd_q);
	if (complete) {
		bt_cb(skb)->hci.req_complete = complete;
	} else if (complete_skb) {
		bt_cb(skb)->hci.req_complete_skb = complete_skb;
		bt_cb(skb)->hci.req_flags |= HCI_REQ_SKB;
	}

	spin_lock_irqsave(&hdev->cmd_q.lock, flags);
	skb_queue_splice_tail(&req->cmd_q, &hdev->cmd_q);
	spin_unlock_irqrestore(&hdev->cmd_q.lock, flags);

	queue_work(hdev->workqueue, &hdev->cmd_work);

	return 0;
}

int hci_req_run(struct hci_request *req, hci_req_complete_t complete)
{
	return req_run(req, complete, NULL);
}

int hci_req_run_skb(struct hci_request *req, hci_req_complete_skb_t complete)
{
	return req_run(req, NULL, complete);
}

static void hci_req_sync_complete(struct hci_dev *hdev, u8 result, u16 opcode,
				  struct sk_buff *skb)
{
	BT_DBG("%s result 0x%2.2x", hdev->name, result);

	if (hdev->req_status == HCI_REQ_PEND) {
		hdev->req_result = result;
		hdev->req_status = HCI_REQ_DONE;
		if (skb)
			hdev->req_skb = skb_get(skb);
		wake_up_interruptible(&hdev->req_wait_q);
	}
}

void hci_req_sync_cancel(struct hci_dev *hdev, int err)
{
	BT_DBG("%s err 0x%2.2x", hdev->name, err);

	if (hdev->req_status == HCI_REQ_PEND) {
		hdev->req_result = err;
		hdev->req_status = HCI_REQ_CANCELED;
		wake_up_interruptible(&hdev->req_wait_q);
	}
}

struct sk_buff *__hci_cmd_sync_ev(struct hci_dev *hdev, u16 opcode, u32 plen,
				  const void *param, u8 event, u32 timeout)
{
	DECLARE_WAITQUEUE(wait, current);
	struct hci_request req;
	struct sk_buff *skb;
	int err = 0;

	BT_DBG("%s", hdev->name);

	hci_req_init(&req, hdev);

	hci_req_add_ev(&req, opcode, plen, param, event);

	hdev->req_status = HCI_REQ_PEND;

	add_wait_queue(&hdev->req_wait_q, &wait);
	set_current_state(TASK_INTERRUPTIBLE);

	err = hci_req_run_skb(&req, hci_req_sync_complete);
	if (err < 0) {
		remove_wait_queue(&hdev->req_wait_q, &wait);
		set_current_state(TASK_RUNNING);
		return ERR_PTR(err);
	}

	schedule_timeout(timeout);

	remove_wait_queue(&hdev->req_wait_q, &wait);

	if (signal_pending(current))
		return ERR_PTR(-EINTR);

	switch (hdev->req_status) {
	case HCI_REQ_DONE:
		err = -bt_to_errno(hdev->req_result);
		break;

	case HCI_REQ_CANCELED:
		err = -hdev->req_result;
		break;

	default:
		err = -ETIMEDOUT;
		break;
	}

	hdev->req_status = hdev->req_result = 0;
	skb = hdev->req_skb;
	hdev->req_skb = NULL;

	BT_DBG("%s end: err %d", hdev->name, err);

	if (err < 0) {
		kfree_skb(skb);
		return ERR_PTR(err);
	}

	if (!skb)
		return ERR_PTR(-ENODATA);

	return skb;
}
EXPORT_SYMBOL(__hci_cmd_sync_ev);

struct sk_buff *__hci_cmd_sync(struct hci_dev *hdev, u16 opcode, u32 plen,
			       const void *param, u32 timeout)
{
	return __hci_cmd_sync_ev(hdev, opcode, plen, param, 0, timeout);
}
EXPORT_SYMBOL(__hci_cmd_sync);

/* Execute request and wait for completion. */
int __hci_req_sync(struct hci_dev *hdev, int (*func)(struct hci_request *req,
						     unsigned long opt),
		   unsigned long opt, u32 timeout, u8 *hci_status)
{
	struct hci_request req;
	DECLARE_WAITQUEUE(wait, current);
	int err = 0;

	BT_DBG("%s start", hdev->name);

	hci_req_init(&req, hdev);

	hdev->req_status = HCI_REQ_PEND;

	err = func(&req, opt);
	if (err) {
		if (hci_status)
			*hci_status = HCI_ERROR_UNSPECIFIED;
		return err;
	}

	add_wait_queue(&hdev->req_wait_q, &wait);
	set_current_state(TASK_INTERRUPTIBLE);

	err = hci_req_run_skb(&req, hci_req_sync_complete);
	if (err < 0) {
		hdev->req_status = 0;

		remove_wait_queue(&hdev->req_wait_q, &wait);
		set_current_state(TASK_RUNNING);

		/* ENODATA means the HCI request command queue is empty.
		 * This can happen when a request with conditionals doesn't
		 * trigger any commands to be sent. This is normal behavior
		 * and should not trigger an error return.
		 */
		if (err == -ENODATA) {
			if (hci_status)
				*hci_status = 0;
			return 0;
		}

		if (hci_status)
			*hci_status = HCI_ERROR_UNSPECIFIED;

		return err;
	}

	schedule_timeout(timeout);

	remove_wait_queue(&hdev->req_wait_q, &wait);

	if (signal_pending(current))
		return -EINTR;

	switch (hdev->req_status) {
	case HCI_REQ_DONE:
		err = -bt_to_errno(hdev->req_result);
		if (hci_status)
			*hci_status = hdev->req_result;
		break;

	case HCI_REQ_CANCELED:
		err = -hdev->req_result;
		if (hci_status)
			*hci_status = HCI_ERROR_UNSPECIFIED;
		break;

	default:
		err = -ETIMEDOUT;
		if (hci_status)
			*hci_status = HCI_ERROR_UNSPECIFIED;
		break;
	}

	hdev->req_status = hdev->req_result = 0;

	BT_DBG("%s end: err %d", hdev->name, err);

	return err;
}

int hci_req_sync(struct hci_dev *hdev, int (*req)(struct hci_request *req,
						  unsigned long opt),
		 unsigned long opt, u32 timeout, u8 *hci_status)
{
	int ret;

	if (!test_bit(HCI_UP, &hdev->flags))
		return -ENETDOWN;

	/* Serialize all requests */
	hci_req_sync_lock(hdev);
	ret = __hci_req_sync(hdev, req, opt, timeout, hci_status);
	hci_req_sync_unlock(hdev);

	return ret;
}

struct sk_buff *hci_prepare_cmd(struct hci_dev *hdev, u16 opcode, u32 plen,
				const void *param)
{
	int len = HCI_COMMAND_HDR_SIZE + plen;
	struct hci_command_hdr *hdr;
	struct sk_buff *skb;

	skb = bt_skb_alloc(len, GFP_ATOMIC);
	if (!skb)
		return NULL;

	hdr = (struct hci_command_hdr *) skb_put(skb, HCI_COMMAND_HDR_SIZE);
	hdr->opcode = cpu_to_le16(opcode);
	hdr->plen   = plen;

	if (plen)
		memcpy(skb_put(skb, plen), param, plen);

	BT_DBG("skb len %d", skb->len);

	hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;
	hci_skb_opcode(skb) = opcode;

	return skb;
}

/* Queue a command to an asynchronous HCI request */
void hci_req_add_ev(struct hci_request *req, u16 opcode, u32 plen,
		    const void *param, u8 event)
{
	struct hci_dev *hdev = req->hdev;
	struct sk_buff *skb;

	BT_DBG("%s opcode 0x%4.4x plen %d", hdev->name, opcode, plen);

	/* If an error occurred during request building, there is no point in
	 * queueing the HCI command. We can simply return.
	 */
	if (req->err)
		return;

	skb = hci_prepare_cmd(hdev, opcode, plen, param);
	if (!skb) {
		BT_ERR("%s no memory for command (opcode 0x%4.4x)",
		       hdev->name, opcode);
		req->err = -ENOMEM;
		return;
	}

	if (skb_queue_empty(&req->cmd_q))
		bt_cb(skb)->hci.req_flags |= HCI_REQ_START;

	bt_cb(skb)->hci.req_event = event;

	skb_queue_tail(&req->cmd_q, skb);
}

void hci_req_add(struct hci_request *req, u16 opcode, u32 plen,
		 const void *param)
{
	hci_req_add_ev(req, opcode, plen, param, 0);
}

/* This function controls the background scanning based on hdev->pend_le_conns
 * list. If there are pending LE connection we start the background scanning,
 * otherwise we stop it.
 *
 * This function requires the caller holds hdev->lock.
 */
static void __hci_update_background_scan(struct hci_request *req)
{
	struct hci_dev *hdev = req->hdev;

	if (!test_bit(HCI_UP, &hdev->flags) ||
	    test_bit(HCI_INIT, &hdev->flags) ||
	    hci_dev_test_flag(hdev, HCI_SETUP) ||
	    hci_dev_test_flag(hdev, HCI_CONFIG) ||
	    hci_dev_test_flag(hdev, HCI_AUTO_OFF) ||
	    hci_dev_test_flag(hdev, HCI_UNREGISTER))
		return;

	/* No point in doing scanning if LE support hasn't been enabled */
	if (!hci_dev_test_flag(hdev, HCI_LE_ENABLED))
		return;

	/* If discovery is active don't interfere with it */
	if (hdev->discovery.state != DISCOVERY_STOPPED)
		return;

	/* Reset RSSI and UUID filters when starting background scanning
	 * since these filters are meant for service discovery only.
	 *
	 * The Start Discovery and Start Service Discovery operations
	 * ensure to set proper values for RSSI threshold and UUID
	 * filter list. So it is safe to just reset them here.
	 */
	hci_discovery_filter_clear(hdev);

	if (list_empty(&hdev->pend_le_conns) &&
	    list_empty(&hdev->pend_le_reports)) {
		/* If there is no pending LE connections or devices
		 * to be scanned for, we should stop the background
		 * scanning.
		 */

		/* If controller is not scanning we are done. */
		if (!hci_dev_test_flag(hdev, HCI_LE_SCAN))
			return;

		hci_req_add_le_scan_disable(req);

		BT_DBG("%s stopping background scanning", hdev->name);
	} else {
		/* If there is at least one pending LE connection, we should
		 * keep the background scan running.
		 */

		/* If controller is connecting, we should not start scanning
		 * since some controllers are not able to scan and connect at
		 * the same time.
		 */
		if (hci_lookup_le_connect(hdev))
			return;

		/* If controller is currently scanning, we stop it to ensure we
		 * don't miss any advertising (due to duplicates filter).
		 */
		if (hci_dev_test_flag(hdev, HCI_LE_SCAN))
			hci_req_add_le_scan_disable(req);

		hci_req_add_le_passive_scan(req);

		BT_DBG("%s starting background scanning", hdev->name);
	}
}

void hci_req_add_le_scan_disable(struct hci_request *req)
{
	struct hci_cp_le_set_scan_enable cp;

	memset(&cp, 0, sizeof(cp));
	cp.enable = LE_SCAN_DISABLE;
	hci_req_add(req, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(cp), &cp);
}

static void add_to_white_list(struct hci_request *req,
			      struct hci_conn_params *params)
{
	struct hci_cp_le_add_to_white_list cp;

	cp.bdaddr_type = params->addr_type;
	bacpy(&cp.bdaddr, &params->addr);

	hci_req_add(req, HCI_OP_LE_ADD_TO_WHITE_LIST, sizeof(cp), &cp);
}

static u8 update_white_list(struct hci_request *req)
{
	struct hci_dev *hdev = req->hdev;
	struct hci_conn_params *params;
	struct bdaddr_list *b;
	uint8_t white_list_entries = 0;

	/* Go through the current white list programmed into the
	 * controller one by one and check if that address is still
	 * in the list of pending connections or list of devices to
	 * report. If not present in either list, then queue the
	 * command to remove it from the controller.
	 */
	list_for_each_entry(b, &hdev->le_white_list, list) {
		struct hci_cp_le_del_from_white_list cp;

		if (hci_pend_le_action_lookup(&hdev->pend_le_conns,
					      &b->bdaddr, b->bdaddr_type) ||
		    hci_pend_le_action_lookup(&hdev->pend_le_reports,
					      &b->bdaddr, b->bdaddr_type)) {
			white_list_entries++;
			continue;
		}

		cp.bdaddr_type = b->bdaddr_type;
		bacpy(&cp.bdaddr, &b->bdaddr);

		hci_req_add(req, HCI_OP_LE_DEL_FROM_WHITE_LIST,
			    sizeof(cp), &cp);
	}

	/* Since all no longer valid white list entries have been
	 * removed, walk through the list of pending connections
	 * and ensure that any new device gets programmed into
	 * the controller.
	 *
	 * If the list of the devices is larger than the list of
	 * available white list entries in the controller, then
	 * just abort and return filer policy value to not use the
	 * white list.
	 */
	list_for_each_entry(params, &hdev->pend_le_conns, action) {
		if (hci_bdaddr_list_lookup(&hdev->le_white_list,
					   &params->addr, params->addr_type))
			continue;

		if (white_list_entries >= hdev->le_white_list_size) {
			/* Select filter policy to accept all advertising */
			return 0x00;
		}

		if (hci_find_irk_by_addr(hdev, &params->addr,
					 params->addr_type)) {
			/* White list can not be used with RPAs */
			return 0x00;
		}

		white_list_entries++;
		add_to_white_list(req, params);
	}

	/* After adding all new pending connections, walk through
	 * the list of pending reports and also add these to the
	 * white list if there is still space.
	 */
	list_for_each_entry(params, &hdev->pend_le_reports, action) {
		if (hci_bdaddr_list_lookup(&hdev->le_white_list,
					   &params->addr, params->addr_type))
			continue;

		if (white_list_entries >= hdev->le_white_list_size) {
			/* Select filter policy to accept all advertising */
			return 0x00;
		}

		if (hci_find_irk_by_addr(hdev, &params->addr,
					 params->addr_type)) {
			/* White list can not be used with RPAs */
			return 0x00;
		}

		white_list_entries++;
		add_to_white_list(req, params);
	}

	/* Select filter policy to use white list */
	return 0x01;
}

void hci_req_add_le_passive_scan(struct hci_request *req)
{
	struct hci_cp_le_set_scan_param param_cp;
	struct hci_cp_le_set_scan_enable enable_cp;
	struct hci_dev *hdev = req->hdev;
	u8 own_addr_type;
	u8 filter_policy;

	/* Set require_privacy to false since no SCAN_REQ are send
	 * during passive scanning. Not using an non-resolvable address
	 * here is important so that peer devices using direct
	 * advertising with our address will be correctly reported
	 * by the controller.
	 */
	if (hci_update_random_address(req, false, &own_addr_type))
		return;

	/* Adding or removing entries from the white list must
	 * happen before enabling scanning. The controller does
	 * not allow white list modification while scanning.
	 */
	filter_policy = update_white_list(req);

	/* When the controller is using random resolvable addresses and
	 * with that having LE privacy enabled, then controllers with
	 * Extended Scanner Filter Policies support can now enable support
	 * for handling directed advertising.
	 *
	 * So instead of using filter polices 0x00 (no whitelist)
	 * and 0x01 (whitelist enabled) use the new filter policies
	 * 0x02 (no whitelist) and 0x03 (whitelist enabled).
	 */
	if (hci_dev_test_flag(hdev, HCI_PRIVACY) &&
	    (hdev->le_features[0] & HCI_LE_EXT_SCAN_POLICY))
		filter_policy |= 0x02;

	memset(&param_cp, 0, sizeof(param_cp));
	param_cp.type = LE_SCAN_PASSIVE;
	param_cp.interval = cpu_to_le16(hdev->le_scan_interval);
	param_cp.window = cpu_to_le16(hdev->le_scan_window);
	param_cp.own_address_type = own_addr_type;
	param_cp.filter_policy = filter_policy;
	hci_req_add(req, HCI_OP_LE_SET_SCAN_PARAM, sizeof(param_cp),
		    &param_cp);

	memset(&enable_cp, 0, sizeof(enable_cp));
	enable_cp.enable = LE_SCAN_ENABLE;
	enable_cp.filter_dup = LE_SCAN_FILTER_DUP_ENABLE;
	hci_req_add(req, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(enable_cp),
		    &enable_cp);
}

static u8 get_current_adv_instance(struct hci_dev *hdev)
{
	/* The "Set Advertising" setting supersedes the "Add Advertising"
	 * setting. Here we set the advertising data based on which
	 * setting was set. When neither apply, default to the global settings,
	 * represented by instance "0".
	 */
	if (hci_dev_test_flag(hdev, HCI_ADVERTISING_INSTANCE) &&
	    !hci_dev_test_flag(hdev, HCI_ADVERTISING))
		return hdev->cur_adv_instance;

	return 0x00;
}

static u8 get_cur_adv_instance_scan_rsp_len(struct hci_dev *hdev)
{
	u8 instance = get_current_adv_instance(hdev);
	struct adv_info *adv_instance;

	/* Ignore instance 0 */
	if (instance == 0x00)
		return 0;

	adv_instance = hci_find_adv_instance(hdev, instance);
	if (!adv_instance)
		return 0;

	/* TODO: Take into account the "appearance" and "local-name" flags here.
	 * These are currently being ignored as they are not supported.
	 */
	return adv_instance->scan_rsp_len;
}

void __hci_req_disable_advertising(struct hci_request *req)
{
	u8 enable = 0x00;

	hci_req_add(req, HCI_OP_LE_SET_ADV_ENABLE, sizeof(enable), &enable);
}

static u32 get_adv_instance_flags(struct hci_dev *hdev, u8 instance)
{
	u32 flags;
	struct adv_info *adv_instance;

	if (instance == 0x00) {
		/* Instance 0 always manages the "Tx Power" and "Flags"
		 * fields
		 */
		flags = MGMT_ADV_FLAG_TX_POWER | MGMT_ADV_FLAG_MANAGED_FLAGS;

		/* For instance 0, the HCI_ADVERTISING_CONNECTABLE setting
		 * corresponds to the "connectable" instance flag.
		 */
		if (hci_dev_test_flag(hdev, HCI_ADVERTISING_CONNECTABLE))
			flags |= MGMT_ADV_FLAG_CONNECTABLE;

		return flags;
	}

	adv_instance = hci_find_adv_instance(hdev, instance);

	/* Return 0 when we got an invalid instance identifier. */
	if (!adv_instance)
		return 0;

	return adv_instance->flags;
}

void __hci_req_enable_advertising(struct hci_request *req)
{
	struct hci_dev *hdev = req->hdev;
	struct hci_cp_le_set_adv_param cp;
	u8 own_addr_type, enable = 0x01;
	bool connectable;
	u8 instance;
	u32 flags;

	if (hci_conn_num(hdev, LE_LINK) > 0)
		return;

	if (hci_dev_test_flag(hdev, HCI_LE_ADV))
		__hci_req_disable_advertising(req);

	/* Clear the HCI_LE_ADV bit temporarily so that the
	 * hci_update_random_address knows that it's safe to go ahead
	 * and write a new random address. The flag will be set back on
	 * as soon as the SET_ADV_ENABLE HCI command completes.
	 */
	hci_dev_clear_flag(hdev, HCI_LE_ADV);

	instance = get_current_adv_instance(hdev);
	flags = get_adv_instance_flags(hdev, instance);

	/* If the "connectable" instance flag was not set, then choose between
	 * ADV_IND and ADV_NONCONN_IND based on the global connectable setting.
	 */
	connectable = (flags & MGMT_ADV_FLAG_CONNECTABLE) ||
		      mgmt_get_connectable(hdev);

	/* Set require_privacy to true only when non-connectable
	 * advertising is used. In that case it is fine to use a
	 * non-resolvable private address.
	 */
	if (hci_update_random_address(req, !connectable, &own_addr_type) < 0)
		return;

	memset(&cp, 0, sizeof(cp));
	cp.min_interval = cpu_to_le16(hdev->le_adv_min_interval);
	cp.max_interval = cpu_to_le16(hdev->le_adv_max_interval);

	if (connectable)
		cp.type = LE_ADV_IND;
	else if (get_cur_adv_instance_scan_rsp_len(hdev))
		cp.type = LE_ADV_SCAN_IND;
	else
		cp.type = LE_ADV_NONCONN_IND;

	cp.own_address_type = own_addr_type;
	cp.channel_map = hdev->le_adv_channel_map;

	hci_req_add(req, HCI_OP_LE_SET_ADV_PARAM, sizeof(cp), &cp);

	hci_req_add(req, HCI_OP_LE_SET_ADV_ENABLE, sizeof(enable), &enable);
}

static u8 create_default_scan_rsp_data(struct hci_dev *hdev, u8 *ptr)
{
	u8 ad_len = 0;
	size_t name_len;

	name_len = strlen(hdev->dev_name);
	if (name_len > 0) {
		size_t max_len = HCI_MAX_AD_LENGTH - ad_len - 2;

		if (name_len > max_len) {
			name_len = max_len;
			ptr[1] = EIR_NAME_SHORT;
		} else
			ptr[1] = EIR_NAME_COMPLETE;

		ptr[0] = name_len + 1;

		memcpy(ptr + 2, hdev->dev_name, name_len);

		ad_len += (name_len + 2);
		ptr += (name_len + 2);
	}

	return ad_len;
}

static u8 create_instance_scan_rsp_data(struct hci_dev *hdev, u8 instance,
					u8 *ptr)
{
	struct adv_info *adv_instance;

	adv_instance = hci_find_adv_instance(hdev, instance);
	if (!adv_instance)
		return 0;

	/* TODO: Set the appropriate entries based on advertising instance flags
	 * here once flags other than 0 are supported.
	 */
	memcpy(ptr, adv_instance->scan_rsp_data,
	       adv_instance->scan_rsp_len);

	return adv_instance->scan_rsp_len;
}

static void update_inst_scan_rsp_data(struct hci_request *req, u8 instance)
{
	struct hci_dev *hdev = req->hdev;
	struct hci_cp_le_set_scan_rsp_data cp;
	u8 len;

	if (!hci_dev_test_flag(hdev, HCI_LE_ENABLED))
		return;

	memset(&cp, 0, sizeof(cp));

	if (instance)
		len = create_instance_scan_rsp_data(hdev, instance, cp.data);
	else
		len = create_default_scan_rsp_data(hdev, cp.data);

	if (hdev->scan_rsp_data_len == len &&
	    !memcmp(cp.data, hdev->scan_rsp_data, len))
		return;

	memcpy(hdev->scan_rsp_data, cp.data, sizeof(cp.data));
	hdev->scan_rsp_data_len = len;

	cp.length = len;

	hci_req_add(req, HCI_OP_LE_SET_SCAN_RSP_DATA, sizeof(cp), &cp);
}

void __hci_req_update_scan_rsp_data(struct hci_request *req, int instance)
{
	if (instance == HCI_ADV_CURRENT)
		instance = get_current_adv_instance(req->hdev);

	update_inst_scan_rsp_data(req, get_current_adv_instance(req->hdev));
}

static u8 create_instance_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr)
{
	struct adv_info *adv_instance = NULL;
	u8 ad_len = 0, flags = 0;
	u32 instance_flags;

	/* Return 0 when the current instance identifier is invalid. */
	if (instance) {
		adv_instance = hci_find_adv_instance(hdev, instance);
		if (!adv_instance)
			return 0;
	}

	instance_flags = get_adv_instance_flags(hdev, instance);

	/* The Add Advertising command allows userspace to set both the general
	 * and limited discoverable flags.
	 */
	if (instance_flags & MGMT_ADV_FLAG_DISCOV)
		flags |= LE_AD_GENERAL;

	if (instance_flags & MGMT_ADV_FLAG_LIMITED_DISCOV)
		flags |= LE_AD_LIMITED;

	if (flags || (instance_flags & MGMT_ADV_FLAG_MANAGED_FLAGS)) {
		/* If a discovery flag wasn't provided, simply use the global
		 * settings.
		 */
		if (!flags)
			flags |= mgmt_get_adv_discov_flags(hdev);

		if (!hci_dev_test_flag(hdev, HCI_BREDR_ENABLED))
			flags |= LE_AD_NO_BREDR;

		/* If flags would still be empty, then there is no need to
		 * include the "Flags" AD field".
		 */
		if (flags) {
			ptr[0] = 0x02;
			ptr[1] = EIR_FLAGS;
			ptr[2] = flags;

			ad_len += 3;
			ptr += 3;
		}
	}

	if (adv_instance) {
		memcpy(ptr, adv_instance->adv_data,
		       adv_instance->adv_data_len);
		ad_len += adv_instance->adv_data_len;
		ptr += adv_instance->adv_data_len;
	}

	/* Provide Tx Power only if we can provide a valid value for it */
	if (hdev->adv_tx_power != HCI_TX_POWER_INVALID &&
	    (instance_flags & MGMT_ADV_FLAG_TX_POWER)) {
		ptr[0] = 0x02;
		ptr[1] = EIR_TX_POWER;
		ptr[2] = (u8)hdev->adv_tx_power;

		ad_len += 3;
		ptr += 3;
	}

	return ad_len;
}

static void update_inst_adv_data(struct hci_request *req, u8 instance)
{
	struct hci_dev *hdev = req->hdev;
	struct hci_cp_le_set_adv_data cp;
	u8 len;

	if (!hci_dev_test_flag(hdev, HCI_LE_ENABLED))
		return;

	memset(&cp, 0, sizeof(cp));

	len = create_instance_adv_data(hdev, instance, cp.data);

	/* There's nothing to do if the data hasn't changed */
	if (hdev->adv_data_len == len &&
	    memcmp(cp.data, hdev->adv_data, len) == 0)
		return;

	memcpy(hdev->adv_data, cp.data, sizeof(cp.data));
	hdev->adv_data_len = len;

	cp.length = len;

	hci_req_add(req, HCI_OP_LE_SET_ADV_DATA, sizeof(cp), &cp);
}

void __hci_req_update_adv_data(struct hci_request *req, int instance)
{
	if (instance == HCI_ADV_CURRENT)
		instance = get_current_adv_instance(req->hdev);

	update_inst_adv_data(req, instance);
}

int hci_req_update_adv_data(struct hci_dev *hdev, int instance)
{
	struct hci_request req;

	hci_req_init(&req, hdev);
	__hci_req_update_adv_data(&req, instance);

	return hci_req_run(&req, NULL);
}

static void adv_enable_complete(struct hci_dev *hdev, u8 status, u16 opcode)
{
	BT_DBG("%s status %u", hdev->name, status);
}

void hci_req_reenable_advertising(struct hci_dev *hdev)
{
	struct hci_request req;
	u8 instance;

	if (!hci_dev_test_flag(hdev, HCI_ADVERTISING) &&
	    !hci_dev_test_flag(hdev, HCI_ADVERTISING_INSTANCE))
		return;

	instance = get_current_adv_instance(hdev);

	hci_req_init(&req, hdev);

	if (instance) {
		__hci_req_schedule_adv_instance(&req, instance, true);
	} else {
		__hci_req_update_adv_data(&req, HCI_ADV_CURRENT);
		__hci_req_update_scan_rsp_data(&req, HCI_ADV_CURRENT);
		__hci_req_enable_advertising(&req);
	}

	hci_req_run(&req, adv_enable_complete);
}

static void adv_timeout_expire(struct work_struct *work)
{
	struct hci_dev *hdev = container_of(work, struct hci_dev,
					    adv_instance_expire.work);

	struct hci_request req;
	u8 instance;

	BT_DBG("%s", hdev->name);

	hci_dev_lock(hdev);

	hdev->adv_instance_timeout = 0;

	instance = get_current_adv_instance(hdev);
	if (instance == 0x00)
		goto unlock;

	hci_req_init(&req, hdev);

	hci_req_clear_adv_instance(hdev, &req, instance, false);

	if (list_empty(&hdev->adv_instances))
		__hci_req_disable_advertising(&req);

	if (!skb_queue_empty(&req.cmd_q))
		hci_req_run(&req, NULL);

unlock:
	hci_dev_unlock(hdev);
}

int __hci_req_schedule_adv_instance(struct hci_request *req, u8 instance,
				    bool force)
{
	struct hci_dev *hdev = req->hdev;
	struct adv_info *adv_instance = NULL;
	u16 timeout;

	if (hci_dev_test_flag(hdev, HCI_ADVERTISING) ||
	    !hci_dev_test_flag(hdev, HCI_ADVERTISING_INSTANCE))
		return -EPERM;

	if (hdev->adv_instance_timeout)
		return -EBUSY;

	adv_instance = hci_find_adv_instance(hdev, instance);
	if (!adv_instance)
		return -ENOENT;

	/* A zero timeout means unlimited advertising. As long as there is
	 * only one instance, duration should be ignored. We still set a timeout
	 * in case further instances are being added later on.
	 *
	 * If the remaining lifetime of the instance is more than the duration
	 * then the timeout corresponds to the duration, otherwise it will be
	 * reduced to the remaining instance lifetime.
	 */
	if (adv_instance->timeout == 0 ||
	    adv_instance->duration <= adv_instance->remaining_time)
		timeout = adv_instance->duration;
	else
		timeout = adv_instance->remaining_time;

	/* The remaining time is being reduced unless the instance is being
	 * advertised without time limit.
	 */
	if (adv_instance->timeout)
		adv_instance->remaining_time =
				adv_instance->remaining_time - timeout;

	hdev->adv_instance_timeout = timeout;
	queue_delayed_work(hdev->req_workqueue,
			   &hdev->adv_instance_expire,
			   msecs_to_jiffies(timeout * 1000));

	/* If we're just re-scheduling the same instance again then do not
	 * execute any HCI commands. This happens when a single instance is
	 * being advertised.
	 */
	if (!force && hdev->cur_adv_instance == instance &&
	    hci_dev_test_flag(hdev, HCI_LE_ADV))
		return 0;

	hdev->cur_adv_instance = instance;
	__hci_req_update_adv_data(req, HCI_ADV_CURRENT);
	__hci_req_update_scan_rsp_data(req, HCI_ADV_CURRENT);
	__hci_req_enable_advertising(req);

	return 0;
}

static void cancel_adv_timeout(struct hci_dev *hdev)
{
	if (hdev->adv_instance_timeout) {
		hdev->adv_instance_timeout = 0;
		cancel_delayed_work(&hdev->adv_instance_expire);
	}
}

/* For a single instance:
 * - force == true: The instance will be removed even when its remaining
 *   lifetime is not zero.
 * - force == false: the instance will be deactivated but kept stored unless
 *   the remaining lifetime is zero.
 *
 * For instance == 0x00:
 * - force == true: All instances will be removed regardless of their timeout
 *   setting.
 * - force == false: Only instances that have a timeout will be removed.
 */
void hci_req_clear_adv_instance(struct hci_dev *hdev, struct hci_request *req,
				u8 instance, bool force)
{
	struct adv_info *adv_instance, *n, *next_instance = NULL;
	int err;
	u8 rem_inst;

	/* Cancel any timeout concerning the removed instance(s). */
	if (!instance || hdev->cur_adv_instance == instance)
		cancel_adv_timeout(hdev);

	/* Get the next instance to advertise BEFORE we remove
	 * the current one. This can be the same instance again
	 * if there is only one instance.
	 */
	if (instance && hdev->cur_adv_instance == instance)
		next_instance = hci_get_next_instance(hdev, instance);

	if (instance == 0x00) {
		list_for_each_entry_safe(adv_instance, n, &hdev->adv_instances,
					 list) {
			if (!(force || adv_instance->timeout))
				continue;

			rem_inst = adv_instance->instance;
			err = hci_remove_adv_instance(hdev, rem_inst);
			if (!err)
				mgmt_advertising_removed(NULL, hdev, rem_inst);
		}
		hdev->cur_adv_instance = 0x00;
	} else {
		adv_instance = hci_find_adv_instance(hdev, instance);

		if (force || (adv_instance && adv_instance->timeout &&
			      !adv_instance->remaining_time)) {
			/* Don't advertise a removed instance. */
			if (next_instance &&
			    next_instance->instance == instance)
				next_instance = NULL;

			err = hci_remove_adv_instance(hdev, instance);
			if (!err)
				mgmt_advertising_removed(NULL, hdev, instance);
		}
	}

	if (list_empty(&hdev->adv_instances)) {
		hdev->cur_adv_instance = 0x00;
		hci_dev_clear_flag(hdev, HCI_ADVERTISING_INSTANCE);
	}

	if (!req || !hdev_is_powered(hdev) ||
	    hci_dev_test_flag(hdev, HCI_ADVERTISING))
		return;

	if (next_instance)
		__hci_req_schedule_adv_instance(req, next_instance->instance,
						false);
}

static void set_random_addr(struct hci_request *req, bdaddr_t *rpa)
{
	struct hci_dev *hdev = req->hdev;

	/* If we're advertising or initiating an LE connection we can't
	 * go ahead and change the random address at this time. This is
	 * because the eventual initiator address used for the
	 * subsequently created connection will be undefined (some
	 * controllers use the new address and others the one we had
	 * when the operation started).
	 *
	 * In this kind of scenario skip the update and let the random
	 * address be updated at the next cycle.
	 */
	if (hci_dev_test_flag(hdev, HCI_LE_ADV) ||
	    hci_lookup_le_connect(hdev)) {
		BT_DBG("Deferring random address update");
		hci_dev_set_flag(hdev, HCI_RPA_EXPIRED);
		return;
	}

	hci_req_add(req, HCI_OP_LE_SET_RANDOM_ADDR, 6, rpa);
}

int hci_update_random_address(struct hci_request *req, bool require_privacy,
			      u8 *own_addr_type)
{
	struct hci_dev *hdev = req->hdev;
	int err;

	/* If privacy is enabled use a resolvable private address. If
	 * current RPA has expired or there is something else than
	 * the current RPA in use, then generate a new one.
	 */
	if (hci_dev_test_flag(hdev, HCI_PRIVACY)) {
		int to;

		*own_addr_type = ADDR_LE_DEV_RANDOM;

		if (!hci_dev_test_and_clear_flag(hdev, HCI_RPA_EXPIRED) &&
		    !bacmp(&hdev->random_addr, &hdev->rpa))
			return 0;

		err = smp_generate_rpa(hdev, hdev->irk, &hdev->rpa);
		if (err < 0) {
			BT_ERR("%s failed to generate new RPA", hdev->name);
			return err;
		}

		set_random_addr(req, &hdev->rpa);

		to = msecs_to_jiffies(hdev->rpa_timeout * 1000);
		queue_delayed_work(hdev->workqueue, &hdev->rpa_expired, to);

		return 0;
	}

	/* In case of required privacy without resolvable private address,
	 * use an non-resolvable private address. This is useful for active
	 * scanning and non-connectable advertising.
	 */
	if (require_privacy) {
		bdaddr_t nrpa;

		while (true) {
			/* The non-resolvable private address is generated
			 * from random six bytes with the two most significant
			 * bits cleared.
			 */
			get_random_bytes(&nrpa, 6);
			nrpa.b[5] &= 0x3f;

			/* The non-resolvable private address shall not be
			 * equal to the public address.
			 */
			if (bacmp(&hdev->bdaddr, &nrpa))
				break;
		}

		*own_addr_type = ADDR_LE_DEV_RANDOM;
		set_random_addr(req, &nrpa);
		return 0;
	}

	/* If forcing static address is in use or there is no public
	 * address use the static address as random address (but skip
	 * the HCI command if the current random address is already the
	 * static one.
	 *
	 * In case BR/EDR has been disabled on a dual-mode controller
	 * and a static address has been configured, then use that
	 * address instead of the public BR/EDR address.
	 */
	if (hci_dev_test_flag(hdev, HCI_FORCE_STATIC_ADDR) ||
	    !bacmp(&hdev->bdaddr, BDADDR_ANY) ||
	    (!hci_dev_test_flag(hdev, HCI_BREDR_ENABLED) &&
	     bacmp(&hdev->static_addr, BDADDR_ANY))) {
		*own_addr_type = ADDR_LE_DEV_RANDOM;
		if (bacmp(&hdev->static_addr, &hdev->random_addr))
			hci_req_add(req, HCI_OP_LE_SET_RANDOM_ADDR, 6,
				    &hdev->static_addr);
		return 0;
	}

	/* Neither privacy nor static address is being used so use a
	 * public address.
	 */
	*own_addr_type = ADDR_LE_DEV_PUBLIC;

	return 0;
}

static bool disconnected_whitelist_entries(struct hci_dev *hdev)
{
	struct bdaddr_list *b;

	list_for_each_entry(b, &hdev->whitelist, list) {
		struct hci_conn *conn;

		conn = hci_conn_hash_lookup_ba(hdev, ACL_LINK, &b->bdaddr);
		if (!conn)
			return true;

		if (conn->state != BT_CONNECTED && conn->state != BT_CONFIG)
			return true;
	}

	return false;
}

void __hci_req_update_scan(struct hci_request *req)
{
	struct hci_dev *hdev = req->hdev;
	u8 scan;

	if (!hci_dev_test_flag(hdev, HCI_BREDR_ENABLED))
		return;

	if (!hdev_is_powered(hdev))
		return;

	if (mgmt_powering_down(hdev))
		return;

	if (hci_dev_test_flag(hdev, HCI_CONNECTABLE) ||
	    disconnected_whitelist_entries(hdev))
		scan = SCAN_PAGE;
	else
		scan = SCAN_DISABLED;

	if (hci_dev_test_flag(hdev, HCI_DISCOVERABLE))
		scan |= SCAN_INQUIRY;

	if (test_bit(HCI_PSCAN, &hdev->flags) == !!(scan & SCAN_PAGE) &&
	    test_bit(HCI_ISCAN, &hdev->flags) == !!(scan & SCAN_INQUIRY))
		return;

	hci_req_add(req, HCI_OP_WRITE_SCAN_ENABLE, 1, &scan);
}

static int update_scan(struct hci_request *req, unsigned long opt)
{
	hci_dev_lock(req->hdev);
	__hci_req_update_scan(req);
	hci_dev_unlock(req->hdev);
	return 0;
}

static void scan_update_work(struct work_struct *work)
{
	struct hci_dev *hdev = container_of(work, struct hci_dev, scan_update);

	hci_req_sync(hdev, update_scan, 0, HCI_CMD_TIMEOUT, NULL);
}

static int connectable_update(struct hci_request *req, unsigned long opt)
{
	struct hci_dev *hdev = req->hdev;

	hci_dev_lock(hdev);

	__hci_req_update_scan(req);

	/* If BR/EDR is not enabled and we disable advertising as a
	 * by-product of disabling connectable, we need to update the
	 * advertising flags.
	 */
	if (!hci_dev_test_flag(hdev, HCI_BREDR_ENABLED))
		__hci_req_update_adv_data(req, HCI_ADV_CURRENT);

	/* Update the advertising parameters if necessary */
	if (hci_dev_test_flag(hdev, HCI_ADVERTISING) ||
	    hci_dev_test_flag(hdev, HCI_ADVERTISING_INSTANCE))
		__hci_req_enable_advertising(req);

	__hci_update_background_scan(req);

	hci_dev_unlock(hdev);

	return 0;
}

static void connectable_update_work(struct work_struct *work)
{
	struct hci_dev *hdev = container_of(work, struct hci_dev,
					    connectable_update);
	u8 status;

	hci_req_sync(hdev, connectable_update, 0, HCI_CMD_TIMEOUT, &status);
	mgmt_set_connectable_complete(hdev, status);
}

void __hci_abort_conn(struct hci_request *req, struct hci_conn *conn,
		      u8 reason)
{
	switch (conn->state) {
	case BT_CONNECTED:
	case BT_CONFIG:
		if (conn->type == AMP_LINK) {
			struct hci_cp_disconn_phy_link cp;

			cp.phy_handle = HCI_PHY_HANDLE(conn->handle);
			cp.reason = reason;
			hci_req_add(req, HCI_OP_DISCONN_PHY_LINK, sizeof(cp),
				    &cp);
		} else {
			struct hci_cp_disconnect dc;

			dc.handle = cpu_to_le16(conn->handle);
			dc.reason = reason;
			hci_req_add(req, HCI_OP_DISCONNECT, sizeof(dc), &dc);
		}

		conn->state = BT_DISCONN;

		break;
	case BT_CONNECT:
		if (conn->type == LE_LINK) {
			if (test_bit(HCI_CONN_SCANNING, &conn->flags))
				break;
			hci_req_add(req, HCI_OP_LE_CREATE_CONN_CANCEL,
				    0, NULL);
		} else if (conn->type == ACL_LINK) {
			if (req->hdev->hci_ver < BLUETOOTH_VER_1_2)
				break;
			hci_req_add(req, HCI_OP_CREATE_CONN_CANCEL,
				    6, &conn->dst);
		}
		break;
	case BT_CONNECT2:
		if (conn->type == ACL_LINK) {
			struct hci_cp_reject_conn_req rej;

			bacpy(&rej.bdaddr, &conn->dst);
			rej.reason = reason;

			hci_req_add(req, HCI_OP_REJECT_CONN_REQ,
				    sizeof(rej), &rej);
		} else if (conn->type == SCO_LINK || conn->type == ESCO_LINK) {
			struct hci_cp_reject_sync_conn_req rej;

			bacpy(&rej.bdaddr, &conn->dst);

			/* SCO rejection has its own limited set of
			 * allowed error values (0x0D-0x0F) which isn't
			 * compatible with most values passed to this
			 * function. To be safe hard-code one of the
			 * values that's suitable for SCO.
			 */
			rej.reason = HCI_ERROR_REMOTE_LOW_RESOURCES;

			hci_req_add(req, HCI_OP_REJECT_SYNC_CONN_REQ,
				    sizeof(rej), &rej);
		}
		break;
	default:
		conn->state = BT_CLOSED;
		break;
	}
}

static void abort_conn_complete(struct hci_dev *hdev, u8 status, u16 opcode)
{
	if (status)
		BT_DBG("Failed to abort connection: status 0x%2.2x", status);
}

int hci_abort_conn(struct hci_conn *conn, u8 reason)
{
	struct hci_request req;
	int err;

	hci_req_init(&req, conn->hdev);

	__hci_abort_conn(&req, conn, reason);

	err = hci_req_run(&req, abort_conn_complete);
	if (err && err != -ENODATA) {
		BT_ERR("Failed to run HCI request: err %d", err);
		return err;
	}

	return 0;
}

static int update_bg_scan(struct hci_request *req, unsigned long opt)
{
	hci_dev_lock(req->hdev);
	__hci_update_background_scan(req);
	hci_dev_unlock(req->hdev);
	return 0;
}

static void bg_scan_update(struct work_struct *work)
{
	struct hci_dev *hdev = container_of(work, struct hci_dev,
					    bg_scan_update);
	struct hci_conn *conn;
	u8 status;
	int err;

	err = hci_req_sync(hdev, update_bg_scan, 0, HCI_CMD_TIMEOUT, &status);
	if (!err)
		return;

	hci_dev_lock(hdev);

	conn = hci_conn_hash_lookup_state(hdev, LE_LINK, BT_CONNECT);
	if (conn)
		hci_le_conn_failed(conn, status);

	hci_dev_unlock(hdev);
}

static int le_scan_disable(struct hci_request *req, unsigned long opt)
{
	hci_req_add_le_scan_disable(req);
	return 0;
}

static int bredr_inquiry(struct hci_request *req, unsigned long opt)
{
	u8 length = opt;
	/* General inquiry access code (GIAC) */
	u8 lap[3] = { 0x33, 0x8b, 0x9e };
	struct hci_cp_inquiry cp;

	BT_DBG("%s", req->hdev->name);

	hci_dev_lock(req->hdev);
	hci_inquiry_cache_flush(req->hdev);
	hci_dev_unlock(req->hdev);

	memset(&cp, 0, sizeof(cp));
	memcpy(&cp.lap, lap, sizeof(cp.lap));
	cp.length = length;

	hci_req_add(req, HCI_OP_INQUIRY, sizeof(cp), &cp);

	return 0;
}

static void le_scan_disable_work(struct work_struct *work)
{
	struct hci_dev *hdev = container_of(work, struct hci_dev,
					    le_scan_disable.work);
	u8 status;

	BT_DBG("%s", hdev->name);

	if (!hci_dev_test_flag(hdev, HCI_LE_SCAN))
		return;

	cancel_delayed_work(&hdev->le_scan_restart);

	hci_req_sync(hdev, le_scan_disable, 0, HCI_CMD_TIMEOUT, &status);
	if (status) {
		BT_ERR("Failed to disable LE scan: status 0x%02x", status);
		return;
	}

	hdev->discovery.scan_start = 0;

	/* If we were running LE only scan, change discovery state. If
	 * we were running both LE and BR/EDR inquiry simultaneously,
	 * and BR/EDR inquiry is already finished, stop discovery,
	 * otherwise BR/EDR inquiry will stop discovery when finished.
	 * If we will resolve remote device name, do not change
	 * discovery state.
	 */

	if (hdev->discovery.type == DISCOV_TYPE_LE)
		goto discov_stopped;

	if (hdev->discovery.type != DISCOV_TYPE_INTERLEAVED)
		return;

	if (test_bit(HCI_QUIRK_SIMULTANEOUS_DISCOVERY, &hdev->quirks)) {
		if (!test_bit(HCI_INQUIRY, &hdev->flags) &&
		    hdev->discovery.state != DISCOVERY_RESOLVING)
			goto discov_stopped;

		return;
	}

	hci_req_sync(hdev, bredr_inquiry, DISCOV_INTERLEAVED_INQUIRY_LEN,
		     HCI_CMD_TIMEOUT, &status);
	if (status) {
		BT_ERR("Inquiry failed: status 0x%02x", status);
		goto discov_stopped;
	}

	return;

discov_stopped:
	hci_dev_lock(hdev);
	hci_discovery_set_state(hdev, DISCOVERY_STOPPED);
	hci_dev_unlock(hdev);
}

static int le_scan_restart(struct hci_request *req, unsigned long opt)
{
	struct hci_dev *hdev = req->hdev;
	struct hci_cp_le_set_scan_enable cp;

	/* If controller is not scanning we are done. */
	if (!hci_dev_test_flag(hdev, HCI_LE_SCAN))
		return 0;

	hci_req_add_le_scan_disable(req);

	memset(&cp, 0, sizeof(cp));
	cp.enable = LE_SCAN_ENABLE;
	cp.filter_dup = LE_SCAN_FILTER_DUP_ENABLE;
	hci_req_add(req, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(cp), &cp);

	return 0;
}

static void le_scan_restart_work(struct work_struct *work)
{
	struct hci_dev *hdev = container_of(work, struct hci_dev,
					    le_scan_restart.work);
	unsigned long timeout, duration, scan_start, now;
	u8 status;

	BT_DBG("%s", hdev->name);

	hci_req_sync(hdev, le_scan_restart, 0, HCI_CMD_TIMEOUT, &status);
	if (status) {
		BT_ERR("Failed to restart LE scan: status %d", status);
		return;
	}

	hci_dev_lock(hdev);

	if (!test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks) ||
	    !hdev->discovery.scan_start)
		goto unlock;

	/* When the scan was started, hdev->le_scan_disable has been queued
	 * after duration from scan_start. During scan restart this job
	 * has been canceled, and we need to queue it again after proper
	 * timeout, to make sure that scan does not run indefinitely.
	 */
	duration = hdev->discovery.scan_duration;
	scan_start = hdev->discovery.scan_start;
	now = jiffies;
	if (now - scan_start <= duration) {
		int elapsed;

		if (now >= scan_start)
			elapsed = now - scan_start;
		else
			elapsed = ULONG_MAX - scan_start + now;

		timeout = duration - elapsed;
	} else {
		timeout = 0;
	}

	queue_delayed_work(hdev->req_workqueue,
			   &hdev->le_scan_disable, timeout);

unlock:
	hci_dev_unlock(hdev);
}

static void disable_advertising(struct hci_request *req)
{
	u8 enable = 0x00;

	hci_req_add(req, HCI_OP_LE_SET_ADV_ENABLE, sizeof(enable), &enable);
}

static int active_scan(struct hci_request *req, unsigned long opt)
{
	uint16_t interval = opt;
	struct hci_dev *hdev = req->hdev;
	struct hci_cp_le_set_scan_param param_cp;
	struct hci_cp_le_set_scan_enable enable_cp;
	u8 own_addr_type;
	int err;

	BT_DBG("%s", hdev->name);

	if (hci_dev_test_flag(hdev, HCI_LE_ADV)) {
		hci_dev_lock(hdev);

		/* Don't let discovery abort an outgoing connection attempt
		 * that's using directed advertising.
		 */
		if (hci_lookup_le_connect(hdev)) {
			hci_dev_unlock(hdev);
			return -EBUSY;
		}

		cancel_adv_timeout(hdev);
		hci_dev_unlock(hdev);

		disable_advertising(req);
	}

	/* If controller is scanning, it means the background scanning is
	 * running. Thus, we should temporarily stop it in order to set the
	 * discovery scanning parameters.
	 */
	if (hci_dev_test_flag(hdev, HCI_LE_SCAN))
		hci_req_add_le_scan_disable(req);

	/* All active scans will be done with either a resolvable private
	 * address (when privacy feature has been enabled) or non-resolvable
	 * private address.
	 */
	err = hci_update_random_address(req, true, &own_addr_type);
	if (err < 0)
		own_addr_type = ADDR_LE_DEV_PUBLIC;

	memset(&param_cp, 0, sizeof(param_cp));
	param_cp.type = LE_SCAN_ACTIVE;
	param_cp.interval = cpu_to_le16(interval);
	param_cp.window = cpu_to_le16(DISCOV_LE_SCAN_WIN);
	param_cp.own_address_type = own_addr_type;

	hci_req_add(req, HCI_OP_LE_SET_SCAN_PARAM, sizeof(param_cp),
		    &param_cp);

	memset(&enable_cp, 0, sizeof(enable_cp));
	enable_cp.enable = LE_SCAN_ENABLE;
	enable_cp.filter_dup = LE_SCAN_FILTER_DUP_ENABLE;

	hci_req_add(req, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(enable_cp),
		    &enable_cp);

	return 0;
}

static int interleaved_discov(struct hci_request *req, unsigned long opt)
{
	int err;

	BT_DBG("%s", req->hdev->name);

	err = active_scan(req, opt);
	if (err)
		return err;

	return bredr_inquiry(req, DISCOV_BREDR_INQUIRY_LEN);
}

static void start_discovery(struct hci_dev *hdev, u8 *status)
{
	unsigned long timeout;

	BT_DBG("%s type %u", hdev->name, hdev->discovery.type);

	switch (hdev->discovery.type) {
	case DISCOV_TYPE_BREDR:
		if (!hci_dev_test_flag(hdev, HCI_INQUIRY))
			hci_req_sync(hdev, bredr_inquiry,
				     DISCOV_BREDR_INQUIRY_LEN, HCI_CMD_TIMEOUT,
				     status);
		return;
	case DISCOV_TYPE_INTERLEAVED:
		/* When running simultaneous discovery, the LE scanning time
		 * should occupy the whole discovery time sine BR/EDR inquiry
		 * and LE scanning are scheduled by the controller.
		 *
		 * For interleaving discovery in comparison, BR/EDR inquiry
		 * and LE scanning are done sequentially with separate
		 * timeouts.
		 */
		if (test_bit(HCI_QUIRK_SIMULTANEOUS_DISCOVERY,
			     &hdev->quirks)) {
			timeout = msecs_to_jiffies(DISCOV_LE_TIMEOUT);
			/* During simultaneous discovery, we double LE scan
			 * interval. We must leave some time for the controller
			 * to do BR/EDR inquiry.
			 */
			hci_req_sync(hdev, interleaved_discov,
				     DISCOV_LE_SCAN_INT * 2, HCI_CMD_TIMEOUT,
				     status);
			break;
		}

		timeout = msecs_to_jiffies(hdev->discov_interleaved_timeout);
		hci_req_sync(hdev, active_scan, DISCOV_LE_SCAN_INT,
			     HCI_CMD_TIMEOUT, status);
		break;
	case DISCOV_TYPE_LE:
		timeout = msecs_to_jiffies(DISCOV_LE_TIMEOUT);
		hci_req_sync(hdev, active_scan, DISCOV_LE_SCAN_INT,
			     HCI_CMD_TIMEOUT, status);
		break;
	default:
		*status = HCI_ERROR_UNSPECIFIED;
		return;
	}

	if (*status)
		return;

	BT_DBG("%s timeout %u ms", hdev->name, jiffies_to_msecs(timeout));

	/* When service discovery is used and the controller has a
	 * strict duplicate filter, it is important to remember the
	 * start and duration of the scan. This is required for
	 * restarting scanning during the discovery phase.
	 */
	if (test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks) &&
		     hdev->discovery.result_filtering) {
		hdev->discovery.scan_start = jiffies;
		hdev->discovery.scan_duration = timeout;
	}

	queue_delayed_work(hdev->req_workqueue, &hdev->le_scan_disable,
			   timeout);
}

bool hci_req_stop_discovery(struct hci_request *req)
{
	struct hci_dev *hdev = req->hdev;
	struct discovery_state *d = &hdev->discovery;
	struct hci_cp_remote_name_req_cancel cp;
	struct inquiry_entry *e;
	bool ret = false;

	BT_DBG("%s state %u", hdev->name, hdev->discovery.state);

	if (d->state == DISCOVERY_FINDING || d->state == DISCOVERY_STOPPING) {
		if (test_bit(HCI_INQUIRY, &hdev->flags))
			hci_req_add(req, HCI_OP_INQUIRY_CANCEL, 0, NULL);

		if (hci_dev_test_flag(hdev, HCI_LE_SCAN)) {
			cancel_delayed_work(&hdev->le_scan_disable);
			hci_req_add_le_scan_disable(req);
		}

		ret = true;
	} else {
		/* Passive scanning */
		if (hci_dev_test_flag(hdev, HCI_LE_SCAN)) {
			hci_req_add_le_scan_disable(req);
			ret = true;
		}
	}

	/* No further actions needed for LE-only discovery */
	if (d->type == DISCOV_TYPE_LE)
		return ret;

	if (d->state == DISCOVERY_RESOLVING || d->state == DISCOVERY_STOPPING) {
		e = hci_inquiry_cache_lookup_resolve(hdev, BDADDR_ANY,
						     NAME_PENDING);
		if (!e)
			return ret;

		bacpy(&cp.bdaddr, &e->data.bdaddr);
		hci_req_add(req, HCI_OP_REMOTE_NAME_REQ_CANCEL, sizeof(cp),
			    &cp);
		ret = true;
	}

	return ret;
}

static int stop_discovery(struct hci_request *req, unsigned long opt)
{
	hci_dev_lock(req->hdev);
	hci_req_stop_discovery(req);
	hci_dev_unlock(req->hdev);

	return 0;
}

static void discov_update(struct work_struct *work)
{
	struct hci_dev *hdev = container_of(work, struct hci_dev,
					    discov_update);
	u8 status = 0;

	switch (hdev->discovery.state) {
	case DISCOVERY_STARTING:
		start_discovery(hdev, &status);
		mgmt_start_discovery_complete(hdev, status);
		if (status)
			hci_discovery_set_state(hdev, DISCOVERY_STOPPED);
		else
			hci_discovery_set_state(hdev, DISCOVERY_FINDING);
		break;
	case DISCOVERY_STOPPING:
		hci_req_sync(hdev, stop_discovery, 0, HCI_CMD_TIMEOUT, &status);
		mgmt_stop_discovery_complete(hdev, status);
		if (!status)
			hci_discovery_set_state(hdev, DISCOVERY_STOPPED);
		break;
	case DISCOVERY_STOPPED:
	default:
		return;
	}
}

void hci_request_setup(struct hci_dev *hdev)
{
	INIT_WORK(&hdev->discov_update, discov_update);
	INIT_WORK(&hdev->bg_scan_update, bg_scan_update);
	INIT_WORK(&hdev->scan_update, scan_update_work);
	INIT_WORK(&hdev->connectable_update, connectable_update_work);
	INIT_DELAYED_WORK(&hdev->le_scan_disable, le_scan_disable_work);
	INIT_DELAYED_WORK(&hdev->le_scan_restart, le_scan_restart_work);
	INIT_DELAYED_WORK(&hdev->adv_instance_expire, adv_timeout_expire);
}

void hci_request_cancel_all(struct hci_dev *hdev)
{
	hci_req_sync_cancel(hdev, ENODEV);

	cancel_work_sync(&hdev->discov_update);
	cancel_work_sync(&hdev->bg_scan_update);
	cancel_work_sync(&hdev->scan_update);
	cancel_work_sync(&hdev->connectable_update);
	cancel_delayed_work_sync(&hdev->le_scan_disable);
	cancel_delayed_work_sync(&hdev->le_scan_restart);

	if (hdev->adv_instance_timeout) {
		cancel_delayed_work_sync(&hdev->adv_instance_expire);
		hdev->adv_instance_timeout = 0;
	}
}