bta/gatt/bta_gattc_utils.cc

/******************************************************************************
 *
 *  Copyright 2003-2012 Broadcom Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at:
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 ******************************************************************************/

/******************************************************************************
 *
 *  This file contains the GATT client utility function.
 *
 ******************************************************************************/

#define LOG_TAG "bt_bta_gattc"

#include <base/logging.h>

#include <cstdint>

#include "bt_target.h"  // Must be first to define build configuration
#include "bta/gatt/bta_gattc_int.h"
#include "device/include/controller.h"
#include "gd/common/init_flags.h"
#include "osi/include/allocator.h"
#include "osi/include/log.h"
#include "types/bt_transport.h"
#include "types/hci_role.h"
#include "types/raw_address.h"

static uint8_t ble_acceptlist_size() {
  const controller_t* controller = controller_get_interface();
  if (!controller->supports_ble()) {
    return 0;
  }
  return controller->get_ble_acceptlist_size();
}

/*******************************************************************************
 *
 * Function         bta_gattc_cl_get_regcb
 *
 * Description      get registration control block by client interface.
 *
 * Returns          pointer to the regcb
 *
 ******************************************************************************/
tBTA_GATTC_RCB* bta_gattc_cl_get_regcb(uint8_t client_if) {
  uint8_t i = 0;
  tBTA_GATTC_RCB* p_clrcb = &bta_gattc_cb.cl_rcb[0];

  for (i = 0; i < BTA_GATTC_CL_MAX; i++, p_clrcb++) {
    if (p_clrcb->in_use && p_clrcb->client_if == client_if) return p_clrcb;
  }
  return NULL;
}
/*******************************************************************************
 *
 * Function         bta_gattc_num_reg_app
 *
 * Description      find the number of registered application.
 *
 * Returns          pointer to the regcb
 *
 ******************************************************************************/
uint8_t bta_gattc_num_reg_app(void) {
  uint8_t i = 0, j = 0;

  for (i = 0; i < BTA_GATTC_CL_MAX; i++) {
    if (bta_gattc_cb.cl_rcb[i].in_use) j++;
  }
  return j;
}
/*******************************************************************************
 *
 * Function         bta_gattc_find_clcb_by_cif
 *
 * Description      get clcb by client interface and remote bd adddress
 *
 * Returns          pointer to the clcb
 *
 ******************************************************************************/
tBTA_GATTC_CLCB* bta_gattc_find_clcb_by_cif(uint8_t client_if,
                                            const RawAddress& remote_bda,
                                            tBT_TRANSPORT transport) {
  tBTA_GATTC_CLCB* p_clcb = &bta_gattc_cb.clcb[0];
  uint8_t i;

  for (i = 0; i < BTA_GATTC_CLCB_MAX; i++, p_clcb++) {
    if (p_clcb->in_use && p_clcb->p_rcb->client_if == client_if &&
        p_clcb->transport == transport && p_clcb->bda == remote_bda)
      return p_clcb;
  }
  return NULL;
}
/*******************************************************************************
 *
 * Function         bta_gattc_find_clcb_by_conn_id
 *
 * Description      get clcb by connection ID
 *
 * Returns          pointer to the clcb
 *
 ******************************************************************************/
tBTA_GATTC_CLCB* bta_gattc_find_clcb_by_conn_id(uint16_t conn_id) {
  tBTA_GATTC_CLCB* p_clcb = &bta_gattc_cb.clcb[0];
  uint8_t i;

  for (i = 0; i < BTA_GATTC_CLCB_MAX; i++, p_clcb++) {
    if (p_clcb->in_use && p_clcb->bta_conn_id == conn_id) return p_clcb;
  }
  return NULL;
}

/*******************************************************************************
 *
 * Function         bta_gattc_clcb_alloc
 *
 * Description      allocate CLCB
 *
 * Returns          pointer to the clcb
 *
 ******************************************************************************/
tBTA_GATTC_CLCB* bta_gattc_clcb_alloc(tGATT_IF client_if,
                                      const RawAddress& remote_bda,
                                      tBT_TRANSPORT transport) {
  uint8_t i_clcb = 0;
  tBTA_GATTC_CLCB* p_clcb = NULL;

  for (i_clcb = 0; i_clcb < BTA_GATTC_CLCB_MAX; i_clcb++) {
    if (!bta_gattc_cb.clcb[i_clcb].in_use) {
#if (BTA_GATT_DEBUG == TRUE)
      VLOG(1) << __func__ << ": found clcb:" << +i_clcb << " available";
#endif
      p_clcb = &bta_gattc_cb.clcb[i_clcb];
      p_clcb->in_use = true;
      p_clcb->status = GATT_SUCCESS;
      p_clcb->transport = transport;
      p_clcb->bda = remote_bda;
      p_clcb->p_q_cmd = NULL;

      p_clcb->p_rcb = bta_gattc_cl_get_regcb(client_if);

      p_clcb->p_srcb = bta_gattc_find_srcb(remote_bda);
      if (p_clcb->p_srcb == NULL)
        p_clcb->p_srcb = bta_gattc_srcb_alloc(remote_bda);

      if (p_clcb->p_rcb != NULL && p_clcb->p_srcb != NULL) {
        p_clcb->p_srcb->num_clcb++;
        p_clcb->p_rcb->num_clcb++;
      } else {
        /* release this clcb if clcb or srcb allocation failed */
        p_clcb->in_use = false;
        p_clcb = NULL;
      }
      break;
    }
  }
  return p_clcb;
}
/*******************************************************************************
 *
 * Function         bta_gattc_find_alloc_clcb
 *
 * Description      find or allocate CLCB if not found.
 *
 * Returns          pointer to the clcb
 *
 ******************************************************************************/
tBTA_GATTC_CLCB* bta_gattc_find_alloc_clcb(tGATT_IF client_if,
                                           const RawAddress& remote_bda,
                                           tBT_TRANSPORT transport) {
  tBTA_GATTC_CLCB* p_clcb;

  p_clcb = bta_gattc_find_clcb_by_cif(client_if, remote_bda, transport);
  if (p_clcb == NULL) {
    p_clcb = bta_gattc_clcb_alloc(client_if, remote_bda, transport);
  }
  return p_clcb;
}

/*******************************************************************************
 *
 * Function         bta_gattc_server_disconnected
 *
 * Description      Set server cache disconnected
 *
 * Returns          pointer to the srcb
 *
 ******************************************************************************/
void bta_gattc_server_disconnected(tBTA_GATTC_SERV* p_srcb) {
  if (p_srcb && p_srcb->connected) {
    p_srcb->connected = false;
    p_srcb->state = BTA_GATTC_SERV_IDLE;
    p_srcb->mtu = 0;

    // clear reallocating
    p_srcb->gatt_database.Clear();
  }
}

/*******************************************************************************
 *
 * Function         bta_gattc_clcb_dealloc
 *
 * Description      Deallocte a clcb
 *
 * Returns          pointer to the clcb
 *
 ******************************************************************************/
void bta_gattc_clcb_dealloc(tBTA_GATTC_CLCB* p_clcb) {
  if (!p_clcb) {
    LOG(ERROR) << __func__ << " p_clcb=NULL";
    return;
  }

  tBTA_GATTC_SERV* p_srcb = p_clcb->p_srcb;
  if (p_srcb->num_clcb) p_srcb->num_clcb--;

  if (p_clcb->p_rcb->num_clcb) p_clcb->p_rcb->num_clcb--;

  /* if the srcb is no longer needed, reset the state */
  if (p_srcb->num_clcb == 0) {
    p_srcb->connected = false;
    p_srcb->state = BTA_GATTC_SERV_IDLE;
    p_srcb->mtu = 0;

    // clear reallocating
    p_srcb->gatt_database.Clear();
  }

  while (!p_clcb->p_q_cmd_queue.empty()) {
    auto p_q_cmd = p_clcb->p_q_cmd_queue.front();
    p_clcb->p_q_cmd_queue.pop_front();
    osi_free_and_reset((void**)&p_q_cmd);
  }

  if (p_clcb->p_q_cmd != NULL) {
    osi_free_and_reset((void**)&p_clcb->p_q_cmd);
  }

  /* Clear p_clcb. Some of the fields are already reset e.g. p_q_cmd_queue and
   * p_q_cmd. */
  p_clcb->bta_conn_id = 0;
  p_clcb->bda = {};
  p_clcb->transport = 0;
  p_clcb->p_rcb = NULL;
  p_clcb->p_srcb = NULL;
  p_clcb->request_during_discovery = 0;
  p_clcb->auto_update = 0;
  p_clcb->disc_active = 0;
  p_clcb->in_use = 0;
  p_clcb->state = BTA_GATTC_IDLE_ST;
  p_clcb->status = GATT_SUCCESS;
}

/*******************************************************************************
 *
 * Function         bta_gattc_find_srcb
 *
 * Description      find server cache by remote bd address currently in use
 *
 * Returns          pointer to the server cache.
 *
 ******************************************************************************/
tBTA_GATTC_SERV* bta_gattc_find_srcb(const RawAddress& bda) {
  tBTA_GATTC_SERV* p_srcb = &bta_gattc_cb.known_server[0];
  uint8_t i;

  for (i = 0; i < ble_acceptlist_size(); i++, p_srcb++) {
    if (p_srcb->in_use && p_srcb->server_bda == bda) return p_srcb;
  }
  return NULL;
}

/*******************************************************************************
 *
 * Function         bta_gattc_find_srvr_cache
 *
 * Description      find server cache by remote bd address
 *
 * Returns          pointer to the server cache.
 *
 ******************************************************************************/
tBTA_GATTC_SERV* bta_gattc_find_srvr_cache(const RawAddress& bda) {
  tBTA_GATTC_SERV* p_srcb = &bta_gattc_cb.known_server[0];
  uint8_t i;

  for (i = 0; i < ble_acceptlist_size(); i++, p_srcb++) {
    if (p_srcb->server_bda == bda) return p_srcb;
  }
  return NULL;
}
/*******************************************************************************
 *
 * Function         bta_gattc_find_scb_by_cid
 *
 * Description      find server control block by connection ID
 *
 * Returns          pointer to the server cache.
 *
 ******************************************************************************/
tBTA_GATTC_SERV* bta_gattc_find_scb_by_cid(uint16_t conn_id) {
  tBTA_GATTC_CLCB* p_clcb = bta_gattc_find_clcb_by_conn_id(conn_id);

  if (p_clcb)
    return p_clcb->p_srcb;
  else
    return NULL;
}
/*******************************************************************************
 *
 * Function         bta_gattc_srcb_alloc
 *
 * Description      allocate server cache control block
 *
 * Returns          pointer to the server cache.
 *
 ******************************************************************************/
tBTA_GATTC_SERV* bta_gattc_srcb_alloc(const RawAddress& bda) {
  tBTA_GATTC_SERV *p_tcb = &bta_gattc_cb.known_server[0], *p_recycle = NULL;
  bool found = false;
  uint8_t i;

  for (i = 0; i < ble_acceptlist_size(); i++, p_tcb++) {
    if (!p_tcb->in_use) {
      found = true;
      break;
    } else if (!p_tcb->connected) {
      p_recycle = p_tcb;
    }
  }

  /* if not found, try to recycle one known device */
  if (!found && !p_recycle)
    p_tcb = NULL;
  else if (!found && p_recycle)
    p_tcb = p_recycle;

  if (p_tcb != NULL) {
    // clear reallocating
    p_tcb->gatt_database.Clear();
    p_tcb->pending_discovery.Clear();
    *p_tcb = tBTA_GATTC_SERV();

    p_tcb->in_use = true;
    p_tcb->server_bda = bda;
  }
  return p_tcb;
}

void bta_gattc_send_mtu_response(tBTA_GATTC_CLCB* p_clcb,
                                 const tBTA_GATTC_DATA* p_data,
                                 uint16_t current_mtu) {
  GATT_CONFIGURE_MTU_OP_CB cb = p_data->api_mtu.mtu_cb;
  if (cb) {
    void* my_cb_data = p_data->api_mtu.mtu_cb_data;
    cb(p_clcb->bta_conn_id, GATT_SUCCESS, my_cb_data);
  }

  tBTA_GATTC cb_data;
  p_clcb->status = GATT_SUCCESS;
  cb_data.cfg_mtu.conn_id = p_clcb->bta_conn_id;
  cb_data.cfg_mtu.status = GATT_SUCCESS;

  cb_data.cfg_mtu.mtu = current_mtu;

  if (p_clcb->p_rcb) {
    (*p_clcb->p_rcb->p_cback)(BTA_GATTC_CFG_MTU_EVT, &cb_data);
  }
}

void bta_gattc_continue(tBTA_GATTC_CLCB* p_clcb) {
  if (p_clcb->p_q_cmd != NULL) {
    LOG_INFO("Already scheduled another request for conn_id = 0x%04x",
             p_clcb->bta_conn_id);
    return;
  }

  while (!p_clcb->p_q_cmd_queue.empty()) {
    const tBTA_GATTC_DATA* p_q_cmd = p_clcb->p_q_cmd_queue.front();
    if (p_q_cmd->hdr.event != BTA_GATTC_API_CFG_MTU_EVT) {
      p_clcb->p_q_cmd_queue.pop_front();
      bta_gattc_sm_execute(p_clcb, p_q_cmd->hdr.event, p_q_cmd);
      return;
    }

    /* The p_q_cmd is the MTU Request event. */
    uint16_t current_mtu = 0;
    auto result = GATTC_TryMtuRequest(p_clcb->bda, p_clcb->transport,
                                      p_clcb->bta_conn_id, &current_mtu);
    switch (result) {
      case MTU_EXCHANGE_DEVICE_DISCONNECTED:
        bta_gattc_cmpl_sendmsg(p_clcb->bta_conn_id, GATTC_OPTYPE_CONFIG,
                               GATT_NO_RESOURCES, NULL);
        /* Handled, free command below and continue with a p_q_cmd_queue */
        break;
      case MTU_EXCHANGE_NOT_ALLOWED:
        bta_gattc_cmpl_sendmsg(p_clcb->bta_conn_id, GATTC_OPTYPE_CONFIG,
                               GATT_ERR_UNLIKELY, NULL);
        /* Handled, free command below and continue with a p_q_cmd_queue */
        break;
      case MTU_EXCHANGE_ALREADY_DONE:
        bta_gattc_send_mtu_response(p_clcb, p_q_cmd, current_mtu);
        /* Handled, free command below and continue with a p_q_cmd_queue */
        break;
      case MTU_EXCHANGE_IN_PROGRESS:
        LOG_WARN("Waiting p_clcb %p", p_clcb);
        return;
      case MTU_EXCHANGE_NOT_DONE_YET:
        p_clcb->p_q_cmd_queue.pop_front();
        bta_gattc_sm_execute(p_clcb, p_q_cmd->hdr.event, p_q_cmd);
        return;
    }

    /* p_q_cmd was the MTU request and it was handled.
     * If MTU request was handled without actually ATT request,
     * it is ok to take another message from the queue and proceed.
     */
    p_clcb->p_q_cmd_queue.pop_front();
    osi_free_and_reset((void**)&p_q_cmd);
  }
}

bool bta_gattc_is_data_queued(tBTA_GATTC_CLCB* p_clcb,
                              const tBTA_GATTC_DATA* p_data) {
  if (p_clcb->p_q_cmd == p_data) {
    return true;
  }

  auto it = std::find(p_clcb->p_q_cmd_queue.begin(),
                      p_clcb->p_q_cmd_queue.end(), p_data);
  return it != p_clcb->p_q_cmd_queue.end();
}
/*******************************************************************************
 *
 * Function         bta_gattc_enqueue
 *
 * Description      enqueue a client request in clcb.
 *
 * Returns          BtaEnqueuedResult_t
 *
 ******************************************************************************/
BtaEnqueuedResult_t bta_gattc_enqueue(tBTA_GATTC_CLCB* p_clcb,
                                      const tBTA_GATTC_DATA* p_data) {
  if (p_clcb->p_q_cmd == NULL) {
    p_clcb->p_q_cmd = p_data;
    return ENQUEUED_READY_TO_SEND;
  }

  LOG_INFO(
      "Already has a pending command to executer. Queuing for later %s conn "
      "id=0x%04x",
      ADDRESS_TO_LOGGABLE_CSTR(p_clcb->bda), p_clcb->bta_conn_id);
  p_clcb->p_q_cmd_queue.push_back(p_data);

  return ENQUEUED_FOR_LATER;
}

/*******************************************************************************
 *
 * Function         bta_gattc_check_notif_registry
 *
 * Description      check if the service notificaition has been registered.
 *
 * Returns
 *
 ******************************************************************************/
bool bta_gattc_check_notif_registry(tBTA_GATTC_RCB* p_clreg,
                                    tBTA_GATTC_SERV* p_srcb,
                                    tBTA_GATTC_NOTIFY* p_notify) {
  uint8_t i;

  for (i = 0; i < BTA_GATTC_NOTIF_REG_MAX; i++) {
    if (p_clreg->notif_reg[i].in_use &&
        p_clreg->notif_reg[i].remote_bda == p_srcb->server_bda &&
        p_clreg->notif_reg[i].handle == p_notify->handle &&
        !p_clreg->notif_reg[i].app_disconnected) {
      VLOG(1) << "Notification registered!";
      return true;
    }
  }
  return false;
}
/*******************************************************************************
 *
 * Function         bta_gattc_clear_notif_registration
 *
 * Description      Clear up the notification registration information by
 *                  RawAddress.
 *                  Where handle is between start_handle and end_handle, and
 *                  start_handle and end_handle are boundaries of service
 *                  containing characteristic.
 *
 * Returns          None.
 *
 ******************************************************************************/
void bta_gattc_clear_notif_registration(tBTA_GATTC_SERV* p_srcb,
                                        uint16_t conn_id, uint16_t start_handle,
                                        uint16_t end_handle) {
  RawAddress remote_bda;
  tGATT_IF gatt_if;
  tBTA_GATTC_RCB* p_clrcb;
  uint8_t i;
  tBT_TRANSPORT transport;
  uint16_t handle;

  if (GATT_GetConnectionInfor(conn_id, &gatt_if, remote_bda, &transport)) {
    p_clrcb = bta_gattc_cl_get_regcb(gatt_if);
    if (p_clrcb != NULL) {
      for (i = 0; i < BTA_GATTC_NOTIF_REG_MAX; i++) {
        if (p_clrcb->notif_reg[i].in_use &&
            p_clrcb->notif_reg[i].remote_bda == remote_bda) {
          /* It's enough to get service or characteristic handle, as
           * clear boundaries are always around service.
           */
          handle = p_clrcb->notif_reg[i].handle;
          if (handle >= start_handle && handle <= end_handle)
            memset(&p_clrcb->notif_reg[i], 0, sizeof(tBTA_GATTC_NOTIF_REG));
        }
      }
    }
  } else {
    LOG(ERROR) << "can not clear indication/notif registration for unknown app";
  }
  return;
}

/*******************************************************************************
 *
 * Function         bta_gattc_mark_bg_conn
 *
 * Description      mark background connection status when a bg connection is
 *                  initiated or terminated.
 *
 * Returns          true if success; false otherwise.
 *
 ******************************************************************************/
bool bta_gattc_mark_bg_conn(tGATT_IF client_if,
                            const RawAddress& remote_bda_ptr, bool add) {
  tBTA_GATTC_BG_TCK* p_bg_tck = &bta_gattc_cb.bg_track[0];
  uint8_t i = 0;
  tBTA_GATTC_CIF_MASK* p_cif_mask;

  for (i = 0; i < ble_acceptlist_size(); i++, p_bg_tck++) {
    if (p_bg_tck->in_use && ((p_bg_tck->remote_bda == remote_bda_ptr) ||
                             (p_bg_tck->remote_bda.IsEmpty()))) {
      p_cif_mask = &p_bg_tck->cif_mask;

      if (add) /* mask on the cif bit */
        *p_cif_mask |= (1 << (client_if - 1));
      else {
        if (client_if != 0)
          *p_cif_mask &= (~(1 << (client_if - 1)));
        else
          *p_cif_mask = 0;
      }
      /* no BG connection for this device, make it available */
      if (p_bg_tck->cif_mask == 0) {
        memset(p_bg_tck, 0, sizeof(tBTA_GATTC_BG_TCK));
      }
      return true;
    }
  }
  if (!add) {
    LOG(ERROR) << __func__
               << " unable to find the bg connection mask for bd_addr="
               << ADDRESS_TO_LOGGABLE_STR(remote_bda_ptr);
    return false;
  } else /* adding a new device mask */
  {
    for (i = 0, p_bg_tck = &bta_gattc_cb.bg_track[0]; i < ble_acceptlist_size();
         i++, p_bg_tck++) {
      if (!p_bg_tck->in_use) {
        p_bg_tck->in_use = true;
        p_bg_tck->remote_bda = remote_bda_ptr;

        p_cif_mask = &p_bg_tck->cif_mask;

        *p_cif_mask = ((tBTA_GATTC_CIF_MASK)1 << (client_if - 1));
        return true;
      }
    }
    LOG(ERROR) << "no available space to mark the bg connection status";
    return false;
  }
}
/*******************************************************************************
 *
 * Function         bta_gattc_check_bg_conn
 *
 * Description      check if this is a background connection background
 *                  connection.
 *
 * Returns          true if success; false otherwise.
 *
 ******************************************************************************/
bool bta_gattc_check_bg_conn(tGATT_IF client_if, const RawAddress& remote_bda,
                             uint8_t role) {
  tBTA_GATTC_BG_TCK* p_bg_tck = &bta_gattc_cb.bg_track[0];
  uint8_t i = 0;
  bool is_bg_conn = false;

  for (i = 0; i < ble_acceptlist_size() && !is_bg_conn; i++, p_bg_tck++) {
    if (p_bg_tck->in_use && (p_bg_tck->remote_bda == remote_bda ||
                             p_bg_tck->remote_bda.IsEmpty())) {
      if (((p_bg_tck->cif_mask & ((tBTA_GATTC_CIF_MASK)1 << (client_if - 1))) != 0) &&
          role == HCI_ROLE_CENTRAL)
        is_bg_conn = true;
    }
  }
  return is_bg_conn;
}
/*******************************************************************************
 *
 * Function         bta_gattc_send_open_cback
 *
 * Description      send open callback
 *
 * Returns
 *
 ******************************************************************************/
void bta_gattc_send_open_cback(tBTA_GATTC_RCB* p_clreg, tGATT_STATUS status,
                               const RawAddress& remote_bda, uint16_t conn_id,
                               tBT_TRANSPORT transport, uint16_t mtu) {
  tBTA_GATTC cb_data;

  if (p_clreg->p_cback) {
    memset(&cb_data, 0, sizeof(tBTA_GATTC));

    cb_data.open.status = status;
    cb_data.open.client_if = p_clreg->client_if;
    cb_data.open.conn_id = conn_id;
    cb_data.open.mtu = mtu;
    cb_data.open.transport = transport;
    cb_data.open.remote_bda = remote_bda;

    (*p_clreg->p_cback)(BTA_GATTC_OPEN_EVT, &cb_data);
  }
}
/*******************************************************************************
 *
 * Function         bta_gattc_conn_alloc
 *
 * Description      allocate connection tracking spot
 *
 * Returns          pointer to the clcb
 *
 ******************************************************************************/
tBTA_GATTC_CONN* bta_gattc_conn_alloc(const RawAddress& remote_bda) {
  uint8_t i_conn = 0;
  tBTA_GATTC_CONN* p_conn = &bta_gattc_cb.conn_track[0];

  for (i_conn = 0; i_conn < GATT_MAX_PHY_CHANNEL; i_conn++, p_conn++) {
    if (!p_conn->in_use) {
#if (BTA_GATT_DEBUG == TRUE)
      VLOG(1) << __func__ << ": found conn_track:" << +i_conn << " available";
#endif
      p_conn->in_use = true;
      p_conn->remote_bda = remote_bda;
      return p_conn;
    }
  }
  return NULL;
}

/*******************************************************************************
 *
 * Function         bta_gattc_conn_find
 *
 * Description      allocate connection tracking spot
 *
 * Returns          pointer to the clcb
 *
 ******************************************************************************/
tBTA_GATTC_CONN* bta_gattc_conn_find(const RawAddress& remote_bda) {
  uint8_t i_conn = 0;
  tBTA_GATTC_CONN* p_conn = &bta_gattc_cb.conn_track[0];

  for (i_conn = 0; i_conn < GATT_MAX_PHY_CHANNEL; i_conn++, p_conn++) {
    if (p_conn->in_use && remote_bda == p_conn->remote_bda) {
#if (BTA_GATT_DEBUG == TRUE)
      VLOG(1) << __func__ << ": found conn_track:" << +i_conn << " matched";
#endif
      return p_conn;
    }
  }
  return NULL;
}

/*******************************************************************************
 *
 * Function         bta_gattc_conn_find_alloc
 *
 * Description      find or allocate connection tracking spot
 *
 * Returns          pointer to the clcb
 *
 ******************************************************************************/
tBTA_GATTC_CONN* bta_gattc_conn_find_alloc(const RawAddress& remote_bda) {
  tBTA_GATTC_CONN* p_conn = bta_gattc_conn_find(remote_bda);

  if (p_conn == NULL) {
    p_conn = bta_gattc_conn_alloc(remote_bda);
  }
  return p_conn;
}

/*******************************************************************************
 *
 * Function         bta_gattc_conn_dealloc
 *
 * Description      de-allocate connection tracking spot
 *
 * Returns          pointer to the clcb
 *
 ******************************************************************************/
bool bta_gattc_conn_dealloc(const RawAddress& remote_bda) {
  tBTA_GATTC_CONN* p_conn = bta_gattc_conn_find(remote_bda);

  if (p_conn != NULL) {
    p_conn->in_use = false;
    p_conn->remote_bda = RawAddress::kEmpty;
    return true;
  }
  return false;
}

/*******************************************************************************
 *
 * Function         bta_gattc_find_int_conn_clcb
 *
 * Description      try to locate a clcb when an internal connecion event
 *                  arrives.
 *
 * Returns          pointer to the clcb
 *
 ******************************************************************************/
tBTA_GATTC_CLCB* bta_gattc_find_int_conn_clcb(tBTA_GATTC_DATA* p_msg) {
  tBTA_GATTC_CLCB* p_clcb = NULL;

  if (p_msg->int_conn.role == HCI_ROLE_PERIPHERAL)
    bta_gattc_conn_find_alloc(p_msg->int_conn.remote_bda);

  /* try to locate a logic channel */
  p_clcb = bta_gattc_find_clcb_by_cif(p_msg->int_conn.client_if,
                                      p_msg->int_conn.remote_bda,
                                      p_msg->int_conn.transport);
  if (p_clcb == NULL) {
    /* for a background connection or listening connection */
    if (/*p_msg->int_conn.role == HCI_ROLE_PERIPHERAL ||  */
        bta_gattc_check_bg_conn(p_msg->int_conn.client_if,
                                p_msg->int_conn.remote_bda,
                                p_msg->int_conn.role)) {
      /* allocate a new channel */
      p_clcb = bta_gattc_clcb_alloc(p_msg->int_conn.client_if,
                                    p_msg->int_conn.remote_bda,
                                    p_msg->int_conn.transport);
    }
  }
  return p_clcb;
}

/*******************************************************************************
 *
 * Function         bta_gattc_find_int_disconn_clcb
 *
 * Description      try to locate a clcb when an internal disconnect callback
 *                  arrives.
 *
 * Returns          pointer to the clcb
 *
 ******************************************************************************/
tBTA_GATTC_CLCB* bta_gattc_find_int_disconn_clcb(tBTA_GATTC_DATA* p_msg) {
  tBTA_GATTC_CLCB* p_clcb = NULL;

  bta_gattc_conn_dealloc(p_msg->int_conn.remote_bda);
  p_clcb = bta_gattc_find_clcb_by_conn_id(p_msg->int_conn.hdr.layer_specific);
  if (p_clcb == NULL) {
    /* connection attempt failed, send connection callback event */
    p_clcb = bta_gattc_find_clcb_by_cif(p_msg->int_conn.client_if,
                                        p_msg->int_conn.remote_bda,
                                        p_msg->int_conn.transport);
  }
  if (p_clcb == NULL) {
    VLOG(1) << " disconnection ID:" << +p_msg->int_conn.hdr.layer_specific
            << " not used by BTA";
  }
  return p_clcb;
}

/*******************************************************************************
 *
 * Function         bta_gattc_is_robust_caching_enabled
 *
 * Description      check if robust caching is enabled
 *
 * Returns          true if enabled; otherwise false
 *
 ******************************************************************************/
bool bta_gattc_is_robust_caching_enabled() {
  return bluetooth::common::init_flags::gatt_robust_caching_client_is_enabled();
}