/*
   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 <linux/sched/signal.h>

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

#include "smp.h"
#include "hci_request.h"
#include "msft.h"
#include "eir.h"

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;
}

void hci_req_purge(struct hci_request *req)
{
	skb_queue_purge(&req->cmd_q);
}

bool hci_req_status_pend(struct hci_dev *hdev)
{
	return hdev->req_status == HCI_REQ_PEND;
}

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_dev_dbg(hdev, "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);
}

void hci_req_sync_complete(struct hci_dev *hdev, u8 result, u16 opcode,
			   struct sk_buff *skb)
{
	bt_dev_dbg(hdev, "result 0x%2.2x", result);

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

/* 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;
	int err = 0;

	bt_dev_dbg(hdev, "start");

	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;
	}

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

		/* 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;
	}

	err = wait_event_interruptible_timeout(hdev->req_wait_q,
			hdev->req_status != HCI_REQ_PEND, timeout);

	if (err == -ERESTARTSYS)
		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;
	}

	kfree_skb(hdev->req_skb);
	hdev->req_skb = NULL;
	hdev->req_status = hdev->req_result = 0;

	bt_dev_dbg(hdev, "end: err %d", 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;

	/* Serialize all requests */
	hci_req_sync_lock(hdev);
	/* check the state after obtaing the lock to protect the HCI_UP
	 * against any races from hci_dev_do_close when the controller
	 * gets removed.
	 */
	if (test_bit(HCI_UP, &hdev->flags))
		ret = __hci_req_sync(hdev, req, opt, timeout, hci_status);
	else
		ret = -ENETDOWN;
	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 = skb_put(skb, HCI_COMMAND_HDR_SIZE);
	hdr->opcode = cpu_to_le16(opcode);
	hdr->plen   = plen;

	if (plen)
		skb_put_data(skb, param, plen);

	bt_dev_dbg(hdev, "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_dev_dbg(hdev, "opcode 0x%4.4x plen %d", 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_dev_err(hdev, "no memory for command (opcode 0x%4.4x)",
			   opcode);
		req->err = -ENOMEM;
		return;
	}

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

	hci_skb_event(skb) = event;

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

void hci_req_add(struct hci_request *req, u16 opcode, u32 plen,
		 const void *param)
{
	bt_dev_dbg(req->hdev, "HCI_REQ-0x%4.4x", opcode);
	hci_req_add_ev(req, opcode, plen, param, 0);
}

static void start_interleave_scan(struct hci_dev *hdev)
{
	hdev->interleave_scan_state = INTERLEAVE_SCAN_NO_FILTER;
	queue_delayed_work(hdev->req_workqueue,
			   &hdev->interleave_scan, 0);
}

static bool is_interleave_scanning(struct hci_dev *hdev)
{
	return hdev->interleave_scan_state != INTERLEAVE_SCAN_NONE;
}

static void cancel_interleave_scan(struct hci_dev *hdev)
{
	bt_dev_dbg(hdev, "cancelling interleave scan");

	cancel_delayed_work_sync(&hdev->interleave_scan);

	hdev->interleave_scan_state = INTERLEAVE_SCAN_NONE;
}

/* Return true if interleave_scan wasn't started until exiting this function,
 * otherwise, return false
 */
static bool __hci_update_interleaved_scan(struct hci_dev *hdev)
{
	/* Do interleaved scan only if all of the following are true:
	 * - There is at least one ADV monitor
	 * - At least one pending LE connection or one device to be scanned for
	 * - Monitor offloading is not supported
	 * If so, we should alternate between allowlist scan and one without
	 * any filters to save power.
	 */
	bool use_interleaving = hci_is_adv_monitoring(hdev) &&
				!(list_empty(&hdev->pend_le_conns) &&
				  list_empty(&hdev->pend_le_reports)) &&
				hci_get_adv_monitor_offload_ext(hdev) ==
				    HCI_ADV_MONITOR_EXT_NONE;
	bool is_interleaving = is_interleave_scanning(hdev);

	if (use_interleaving && !is_interleaving) {
		start_interleave_scan(hdev);
		bt_dev_dbg(hdev, "starting interleave scan");
		return true;
	}

	if (!use_interleaving && is_interleaving)
		cancel_interleave_scan(hdev);

	return false;
}

void hci_req_add_le_scan_disable(struct hci_request *req, bool rpa_le_conn)
{
	struct hci_dev *hdev = req->hdev;

	if (hdev->scanning_paused) {
		bt_dev_dbg(hdev, "Scanning is paused for suspend");
		return;
	}

	if (use_ext_scan(hdev)) {
		struct hci_cp_le_set_ext_scan_enable cp;

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

	/* Disable address resolution */
	if (hci_dev_test_flag(hdev, HCI_LL_RPA_RESOLUTION) && !rpa_le_conn) {
		__u8 enable = 0x00;

		hci_req_add(req, HCI_OP_LE_SET_ADDR_RESOLV_ENABLE, 1, &enable);
	}
}

static void del_from_accept_list(struct hci_request *req, bdaddr_t *bdaddr,
				 u8 bdaddr_type)
{
	struct hci_cp_le_del_from_accept_list cp;

	cp.bdaddr_type = bdaddr_type;
	bacpy(&cp.bdaddr, bdaddr);

	bt_dev_dbg(req->hdev, "Remove %pMR (0x%x) from accept list", &cp.bdaddr,
		   cp.bdaddr_type);
	hci_req_add(req, HCI_OP_LE_DEL_FROM_ACCEPT_LIST, sizeof(cp), &cp);

	if (use_ll_privacy(req->hdev)) {
		struct smp_irk *irk;

		irk = hci_find_irk_by_addr(req->hdev, bdaddr, bdaddr_type);
		if (irk) {
			struct hci_cp_le_del_from_resolv_list cp;

			cp.bdaddr_type = bdaddr_type;
			bacpy(&cp.bdaddr, bdaddr);

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

/* Adds connection to accept list if needed. On error, returns -1. */
static int add_to_accept_list(struct hci_request *req,
			      struct hci_conn_params *params, u8 *num_entries,
			      bool allow_rpa)
{
	struct hci_cp_le_add_to_accept_list cp;
	struct hci_dev *hdev = req->hdev;

	/* Already in accept list */
	if (hci_bdaddr_list_lookup(&hdev->le_accept_list, &params->addr,
				   params->addr_type))
		return 0;

	/* Select filter policy to accept all advertising */
	if (*num_entries >= hdev->le_accept_list_size)
		return -1;

	/* Accept list can not be used with RPAs */
	if (!allow_rpa &&
	    !hci_dev_test_flag(hdev, HCI_ENABLE_LL_PRIVACY) &&
	    hci_find_irk_by_addr(hdev, &params->addr, params->addr_type)) {
		return -1;
	}

	/* During suspend, only wakeable devices can be in accept list */
	if (hdev->suspended &&
	    !(params->flags & HCI_CONN_FLAG_REMOTE_WAKEUP))
		return 0;

	*num_entries += 1;
	cp.bdaddr_type = params->addr_type;
	bacpy(&cp.bdaddr, &params->addr);

	bt_dev_dbg(hdev, "Add %pMR (0x%x) to accept list", &cp.bdaddr,
		   cp.bdaddr_type);
	hci_req_add(req, HCI_OP_LE_ADD_TO_ACCEPT_LIST, sizeof(cp), &cp);

	if (use_ll_privacy(hdev)) {
		struct smp_irk *irk;

		irk = hci_find_irk_by_addr(hdev, &params->addr,
					   params->addr_type);
		if (irk) {
			struct hci_cp_le_add_to_resolv_list cp;

			cp.bdaddr_type = params->addr_type;
			bacpy(&cp.bdaddr, &params->addr);
			memcpy(cp.peer_irk, irk->val, 16);

			if (hci_dev_test_flag(hdev, HCI_PRIVACY))
				memcpy(cp.local_irk, hdev->irk, 16);
			else
				memset(cp.local_irk, 0, 16);

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

	return 0;
}

static u8 update_accept_list(struct hci_request *req)
{
	struct hci_dev *hdev = req->hdev;
	struct hci_conn_params *params;
	struct bdaddr_list *b;
	u8 num_entries = 0;
	bool pend_conn, pend_report;
	/* We allow usage of accept list even with RPAs in suspend. In the worst
	 * case, we won't be able to wake from devices that use the privacy1.2
	 * features. Additionally, once we support privacy1.2 and IRK
	 * offloading, we can update this to also check for those conditions.
	 */
	bool allow_rpa = hdev->suspended;

	if (use_ll_privacy(hdev))
		allow_rpa = true;

	/* Go through the current accept 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_accept_list, list) {
		pend_conn = hci_pend_le_action_lookup(&hdev->pend_le_conns,
						      &b->bdaddr,
						      b->bdaddr_type);
		pend_report = hci_pend_le_action_lookup(&hdev->pend_le_reports,
							&b->bdaddr,
							b->bdaddr_type);

		/* If the device is not likely to connect or report,
		 * remove it from the accept list.
		 */
		if (!pend_conn && !pend_report) {
			del_from_accept_list(req, &b->bdaddr, b->bdaddr_type);
			continue;
		}

		/* Accept list can not be used with RPAs */
		if (!allow_rpa &&
		    !hci_dev_test_flag(hdev, HCI_ENABLE_LL_PRIVACY) &&
		    hci_find_irk_by_addr(hdev, &b->bdaddr, b->bdaddr_type)) {
			return 0x00;
		}

		num_entries++;
	}

	/* Since all no longer valid accept 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 accept list entries in the controller, then
	 * just abort and return filer policy value to not use the
	 * accept list.
	 */
	list_for_each_entry(params, &hdev->pend_le_conns, action) {
		if (add_to_accept_list(req, params, &num_entries, allow_rpa))
			return 0x00;
	}

	/* After adding all new pending connections, walk through
	 * the list of pending reports and also add these to the
	 * accept list if there is still space. Abort if space runs out.
	 */
	list_for_each_entry(params, &hdev->pend_le_reports, action) {
		if (add_to_accept_list(req, params, &num_entries, allow_rpa))
			return 0x00;
	}

	/* Use the allowlist unless the following conditions are all true:
	 * - We are not currently suspending
	 * - There are 1 or more ADV monitors registered and it's not offloaded
	 * - Interleaved scanning is not currently using the allowlist
	 */
	if (!idr_is_empty(&hdev->adv_monitors_idr) && !hdev->suspended &&
	    hci_get_adv_monitor_offload_ext(hdev) == HCI_ADV_MONITOR_EXT_NONE &&
	    hdev->interleave_scan_state != INTERLEAVE_SCAN_ALLOWLIST)
		return 0x00;

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

static bool scan_use_rpa(struct hci_dev *hdev)
{
	return hci_dev_test_flag(hdev, HCI_PRIVACY);
}

static void hci_req_start_scan(struct hci_request *req, u8 type, u16 interval,
			       u16 window, u8 own_addr_type, u8 filter_policy,
			       bool filter_dup, bool addr_resolv)
{
	struct hci_dev *hdev = req->hdev;

	if (hdev->scanning_paused) {
		bt_dev_dbg(hdev, "Scanning is paused for suspend");
		return;
	}

	if (use_ll_privacy(hdev) && addr_resolv) {
		u8 enable = 0x01;

		hci_req_add(req, HCI_OP_LE_SET_ADDR_RESOLV_ENABLE, 1, &enable);
	}

	/* Use ext scanning if set ext scan param and ext scan enable is
	 * supported
	 */
	if (use_ext_scan(hdev)) {
		struct hci_cp_le_set_ext_scan_params *ext_param_cp;
		struct hci_cp_le_set_ext_scan_enable ext_enable_cp;
		struct hci_cp_le_scan_phy_params *phy_params;
		u8 data[sizeof(*ext_param_cp) + sizeof(*phy_params) * 2];
		u32 plen;

		ext_param_cp = (void *)data;
		phy_params = (void *)ext_param_cp->data;

		memset(ext_param_cp, 0, sizeof(*ext_param_cp));
		ext_param_cp->own_addr_type = own_addr_type;
		ext_param_cp->filter_policy = filter_policy;

		plen = sizeof(*ext_param_cp);

		if (scan_1m(hdev) || scan_2m(hdev)) {
			ext_param_cp->scanning_phys |= LE_SCAN_PHY_1M;

			memset(phy_params, 0, sizeof(*phy_params));
			phy_params->type = type;
			phy_params->interval = cpu_to_le16(interval);
			phy_params->window = cpu_to_le16(window);

			plen += sizeof(*phy_params);
			phy_params++;
		}

		if (scan_coded(hdev)) {
			ext_param_cp->scanning_phys |= LE_SCAN_PHY_CODED;

			memset(phy_params, 0, sizeof(*phy_params));
			phy_params->type = type;
			phy_params->interval = cpu_to_le16(interval);
			phy_params->window = cpu_to_le16(window);

			plen += sizeof(*phy_params);
			phy_params++;
		}

		hci_req_add(req, HCI_OP_LE_SET_EXT_SCAN_PARAMS,
			    plen, ext_param_cp);

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

		hci_req_add(req, HCI_OP_LE_SET_EXT_SCAN_ENABLE,
			    sizeof(ext_enable_cp), &ext_enable_cp);
	} else {
		struct hci_cp_le_set_scan_param param_cp;
		struct hci_cp_le_set_scan_enable enable_cp;

		memset(&param_cp, 0, sizeof(param_cp));
		param_cp.type = type;
		param_cp.interval = cpu_to_le16(interval);
		param_cp.window = cpu_to_le16(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 = filter_dup;
		hci_req_add(req, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(enable_cp),
			    &enable_cp);
	}
}

static void set_random_addr(struct hci_request *req, bdaddr_t *rpa);
static int hci_update_random_address(struct hci_request *req,
				     bool require_privacy, bool use_rpa,
				     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 (use_rpa) {
		/* If Controller supports LL Privacy use own address type is
		 * 0x03
		 */
		if (use_ll_privacy(hdev))
			*own_addr_type = ADDR_LE_DEV_RANDOM_RESOLVED;
		else
			*own_addr_type = ADDR_LE_DEV_RANDOM;

		if (rpa_valid(hdev))
			return 0;

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

		set_random_addr(req, &hdev->rpa);

		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;
}

/* Ensure to call hci_req_add_le_scan_disable() first to disable the
 * controller based address resolution to be able to reconfigure
 * resolving list.
 */
void hci_req_add_le_passive_scan(struct hci_request *req)
{
	struct hci_dev *hdev = req->hdev;
	u8 own_addr_type;
	u8 filter_policy;
	u16 window, interval;
	/* Default is to enable duplicates filter */
	u8 filter_dup = LE_SCAN_FILTER_DUP_ENABLE;
	/* Background scanning should run with address resolution */
	bool addr_resolv = true;

	if (hdev->scanning_paused) {
		bt_dev_dbg(hdev, "Scanning is paused for suspend");
		return;
	}

	/* 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, scan_use_rpa(hdev),
				      &own_addr_type))
		return;

	if (hdev->enable_advmon_interleave_scan &&
	    __hci_update_interleaved_scan(hdev))
		return;

	bt_dev_dbg(hdev, "interleave state %d", hdev->interleave_scan_state);
	/* Adding or removing entries from the accept list must
	 * happen before enabling scanning. The controller does
	 * not allow accept list modification while scanning.
	 */
	filter_policy = update_accept_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 accept list)
	 * and 0x01 (accept list enabled) use the new filter policies
	 * 0x02 (no accept list) and 0x03 (accept list enabled).
	 */
	if (hci_dev_test_flag(hdev, HCI_PRIVACY) &&
	    (hdev->le_features[0] & HCI_LE_EXT_SCAN_POLICY))
		filter_policy |= 0x02;

	if (hdev->suspended) {
		window = hdev->le_scan_window_suspend;
		interval = hdev->le_scan_int_suspend;
	} else if (hci_is_le_conn_scanning(hdev)) {
		window = hdev->le_scan_window_connect;
		interval = hdev->le_scan_int_connect;
	} else if (hci_is_adv_monitoring(hdev)) {
		window = hdev->le_scan_window_adv_monitor;
		interval = hdev->le_scan_int_adv_monitor;

		/* Disable duplicates filter when scanning for advertisement
		 * monitor for the following reasons.
		 *
		 * For HW pattern filtering (ex. MSFT), Realtek and Qualcomm
		 * controllers ignore RSSI_Sampling_Period when the duplicates
		 * filter is enabled.
		 *
		 * For SW pattern filtering, when we're not doing interleaved
		 * scanning, it is necessary to disable duplicates filter,
		 * otherwise hosts can only receive one advertisement and it's
		 * impossible to know if a peer is still in range.
		 */
		filter_dup = LE_SCAN_FILTER_DUP_DISABLE;
	} else {
		window = hdev->le_scan_window;
		interval = hdev->le_scan_interval;
	}

	bt_dev_dbg(hdev, "LE passive scan with accept list = %d",
		   filter_policy);
	hci_req_start_scan(req, LE_SCAN_PASSIVE, interval, window,
			   own_addr_type, filter_policy, filter_dup,
			   addr_resolv);
}

static int hci_req_add_le_interleaved_scan(struct hci_request *req,
					   unsigned long opt)
{
	struct hci_dev *hdev = req->hdev;
	int ret = 0;

	hci_dev_lock(hdev);

	if (hci_dev_test_flag(hdev, HCI_LE_SCAN))
		hci_req_add_le_scan_disable(req, false);
	hci_req_add_le_passive_scan(req);

	switch (hdev->interleave_scan_state) {
	case INTERLEAVE_SCAN_ALLOWLIST:
		bt_dev_dbg(hdev, "next state: allowlist");
		hdev->interleave_scan_state = INTERLEAVE_SCAN_NO_FILTER;
		break;
	case INTERLEAVE_SCAN_NO_FILTER:
		bt_dev_dbg(hdev, "next state: no filter");
		hdev->interleave_scan_state = INTERLEAVE_SCAN_ALLOWLIST;
		break;
	case INTERLEAVE_SCAN_NONE:
		BT_ERR("unexpected error");
		ret = -1;
	}

	hci_dev_unlock(hdev);

	return ret;
}

static void interleave_scan_work(struct work_struct *work)
{
	struct hci_dev *hdev = container_of(work, struct hci_dev,
					    interleave_scan.work);
	u8 status;
	unsigned long timeout;

	if (hdev->interleave_scan_state == INTERLEAVE_SCAN_ALLOWLIST) {
		timeout = msecs_to_jiffies(hdev->advmon_allowlist_duration);
	} else if (hdev->interleave_scan_state == INTERLEAVE_SCAN_NO_FILTER) {
		timeout = msecs_to_jiffies(hdev->advmon_no_filter_duration);
	} else {
		bt_dev_err(hdev, "unexpected error");
		return;
	}

	hci_req_sync(hdev, hci_req_add_le_interleaved_scan, 0,
		     HCI_CMD_TIMEOUT, &status);

	/* Don't continue interleaving if it was canceled */
	if (is_interleave_scanning(hdev))
		queue_delayed_work(hdev->req_workqueue,
				   &hdev->interleave_scan, timeout);
}

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_dev_dbg(hdev, "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);
}

void hci_request_setup(struct hci_dev *hdev)
{
	INIT_DELAYED_WORK(&hdev->interleave_scan, interleave_scan_work);
}

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

	cancel_interleave_scan(hdev);
}