stack/l2cap/l2c_ucd.cc

/******************************************************************************
 *
 *  Copyright (C) 1999-2012 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 L2CAP UCD code
 *
 ******************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "bt_common.h"
#include "bt_types.h"
#include "btm_api.h"
#include "btm_int.h"
#include "btu.h"
#include "hcidefs.h"
#include "hcimsgs.h"
#include "l2c_int.h"
#include "l2cdefs.h"

#if (L2CAP_UCD_INCLUDED == TRUE)

extern fixed_queue_t* btu_bta_alarm_queue;

static bool l2c_ucd_connect(const RawAddress& rem_bda);

/*******************************************************************************
 *
 * Function         l2c_ucd_discover_cback
 *
 * Description      UCD Discover callback
 *
 * Returns          void
 *
 ******************************************************************************/
static void l2c_ucd_discover_cback(const RawAddress& rem_bda, uint8_t info_type,
                                   uint32_t data) {
  tL2C_RCB* p_rcb = &l2cb.rcb_pool[0];
  uint16_t xx;

  L2CAP_TRACE_DEBUG("L2CAP - l2c_ucd_discover_cback");

  for (xx = 0; xx < MAX_L2CAP_CLIENTS; xx++, p_rcb++) {
    if (p_rcb->in_use) {
      /* if this application is waiting UCD reception info */
      if ((info_type == L2CAP_UCD_INFO_TYPE_RECEPTION) &&
          (p_rcb->ucd.state & L2C_UCD_STATE_W4_RECEPTION)) {
        p_rcb->ucd.cb_info.pL2CA_UCD_Discover_Cb(rem_bda, info_type, data);
        p_rcb->ucd.state &= ~(L2C_UCD_STATE_W4_RECEPTION);
      }

      /* if this application is waiting UCD MTU info */
      if ((info_type == L2CAP_UCD_INFO_TYPE_MTU) &&
          (p_rcb->ucd.state & L2C_UCD_STATE_W4_MTU)) {
        p_rcb->ucd.cb_info.pL2CA_UCD_Discover_Cb(rem_bda, info_type, data);
        p_rcb->ucd.state &= ~(L2C_UCD_STATE_W4_MTU);
      }
    }
  }
}

/*******************************************************************************
 *
 * Function         l2c_ucd_data_ind_cback
 *
 * Description      UCD Data callback
 *
 * Returns          void
 *
 ******************************************************************************/
static void l2c_ucd_data_ind_cback(const RawAddress& rem_bda, BT_HDR* p_buf) {
  uint8_t* p;
  uint16_t psm;
  tL2C_RCB* p_rcb;

  L2CAP_TRACE_DEBUG("L2CAP - l2c_ucd_data_ind_cback");

  p = (uint8_t*)(p_buf + 1) + p_buf->offset;
  STREAM_TO_UINT16(psm, p)

  p_buf->offset += L2CAP_UCD_OVERHEAD;
  p_buf->len -= L2CAP_UCD_OVERHEAD;

  p_rcb = l2cu_find_rcb_by_psm(psm);
  if (p_rcb == NULL) {
    L2CAP_TRACE_ERROR("L2CAP - no RCB for l2c_ucd_data_ind_cback, PSM: 0x%04x",
                      psm);
    osi_free(p_buf);
  } else {
    p_rcb->ucd.cb_info.pL2CA_UCD_Data_Cb(rem_bda, p_buf);
  }
}

/*******************************************************************************
 *
 * Function         l2c_ucd_congestion_status_cback
 *
 * Description      UCD Congestion Status callback
 *
 * Returns          void
 *
 ******************************************************************************/
static void l2c_ucd_congestion_status_cback(const RawAddress& rem_bda,
                                            bool is_congested) {
  tL2C_RCB* p_rcb = &l2cb.rcb_pool[0];
  uint16_t xx;

  L2CAP_TRACE_DEBUG("L2CAP - l2c_ucd_congestion_status_cback");

  for (xx = 0; xx < MAX_L2CAP_CLIENTS; xx++, p_rcb++) {
    if ((p_rcb->in_use) && (p_rcb->ucd.state != L2C_UCD_STATE_UNUSED)) {
      if (p_rcb->ucd.cb_info.pL2CA_UCD_Congestion_Status_Cb) {
        L2CAP_TRACE_DEBUG(
            "L2CAP - Calling UCDCongestionStatus_Cb (%d), PSM=0x%04x, BDA: "
            "%08x%04x,",
            is_congested, p_rcb->psm, (rem_bda[0] << 24) + (rem_bda[1] << 16) +
                                          (rem_bda[2] << 8) + rem_bda[3],
            (rem_bda[4] << 8) + rem_bda[5]);

        p_rcb->ucd.cb_info.pL2CA_UCD_Congestion_Status_Cb(rem_bda,
                                                          is_congested);
      }
    }
  }
}

/*******************************************************************************
 *
 * Function         l2c_ucd_disconnect_ind_cback
 *
 * Description      UCD disconnect callback (Prevent to access null pointer)
 *
 * Returns          void
 *
 ******************************************************************************/
static void l2c_ucd_disconnect_ind_cback(uint16_t cid, bool result) {
  /* do nothing */
}

/*******************************************************************************
 *
 * Function         l2c_ucd_config_ind_cback
 *
 * Description      UCD config callback (This prevent to access null pointer)
 *
 * Returns          void
 *
 ******************************************************************************/
static void l2c_ucd_config_ind_cback(uint16_t cid, tL2CAP_CFG_INFO* p_cfg) {
  /* do nothing */
}

/*******************************************************************************
 *
 * Function         l2c_ucd_config_cfm_cback
 *
 * Description      UCD config callback (This prevent to access null pointer)
 *
 * Returns          void
 *
 ******************************************************************************/
static void l2c_ucd_config_cfm_cback(uint16_t cid, tL2CAP_CFG_INFO* p_cfg) {
  /* do nothing */
}

/*******************************************************************************
 *
 *  Function        L2CA_UcdRegister
 *
 *  Description     Register PSM on UCD.
 *
 *  Parameters:     tL2CAP_UCD_CB_INFO
 *
 *  Return value:   true if successs
 *
 ******************************************************************************/
bool L2CA_UcdRegister(uint16_t psm, tL2CAP_UCD_CB_INFO* p_cb_info) {
  tL2C_RCB* p_rcb;

  L2CAP_TRACE_API("L2CA_UcdRegister()  PSM: 0x%04x", psm);

  if ((!p_cb_info->pL2CA_UCD_Discover_Cb) || (!p_cb_info->pL2CA_UCD_Data_Cb)) {
    L2CAP_TRACE_ERROR("L2CAP - no callback registering PSM(0x%04x) on UCD",
                      psm);
    return (false);
  }

  p_rcb = l2cu_find_rcb_by_psm(psm);
  if (p_rcb == NULL) {
    L2CAP_TRACE_ERROR("L2CAP - no RCB for L2CA_UcdRegister, PSM: 0x%04x", psm);
    return (false);
  }

  p_rcb->ucd.state = L2C_UCD_STATE_W4_DATA;
  p_rcb->ucd.cb_info = *p_cb_info;

  /* check if master rcb is created for UCD */
  p_rcb = l2cu_find_rcb_by_psm(L2C_UCD_RCB_ID);
  if (p_rcb == NULL) {
    p_rcb = l2cu_allocate_rcb(L2C_UCD_RCB_ID);
    if (p_rcb == NULL) {
      L2CAP_TRACE_ERROR("L2CAP - no RCB available for L2CA_UcdRegister");
      return (false);
    } else {
      /* these callback functions will forward data to each UCD application */
      p_rcb->ucd.cb_info.pL2CA_UCD_Discover_Cb = l2c_ucd_discover_cback;
      p_rcb->ucd.cb_info.pL2CA_UCD_Data_Cb = l2c_ucd_data_ind_cback;
      p_rcb->ucd.cb_info.pL2CA_UCD_Congestion_Status_Cb =
          l2c_ucd_congestion_status_cback;

      memset(&p_rcb->api, 0, sizeof(tL2CAP_APPL_INFO));
      p_rcb->api.pL2CA_DisconnectInd_Cb = l2c_ucd_disconnect_ind_cback;

      /* This will make L2CAP check UCD congestion callback */
      p_rcb->api.pL2CA_CongestionStatus_Cb = NULL;

      /* do nothing but prevent crash */
      p_rcb->api.pL2CA_ConfigInd_Cb = l2c_ucd_config_ind_cback;
      p_rcb->api.pL2CA_ConfigCfm_Cb = l2c_ucd_config_cfm_cback;
    }
  }

  return (true);
}

/*******************************************************************************
 *
 *  Function        L2CA_UcdDeregister
 *
 *  Description     Deregister PSM on UCD.
 *
 *  Parameters:     PSM
 *
 *  Return value:   true if successs
 *
 ******************************************************************************/
bool L2CA_UcdDeregister(uint16_t psm) {
  tL2C_CCB* p_ccb;
  tL2C_RCB* p_rcb;
  uint16_t xx;

  L2CAP_TRACE_API("L2CA_UcdDeregister()  PSM: 0x%04x", psm);

  p_rcb = l2cu_find_rcb_by_psm(psm);
  if (p_rcb == NULL) {
    L2CAP_TRACE_ERROR("L2CAP - no RCB for L2CA_UcdDeregister, PSM: 0x%04x",
                      psm);
    return (false);
  }

  p_rcb->ucd.state = L2C_UCD_STATE_UNUSED;

  /* check this was the last UCD registration */
  p_rcb = &l2cb.rcb_pool[0];

  for (xx = 0; xx < MAX_L2CAP_CLIENTS; xx++, p_rcb++) {
    if ((p_rcb->in_use) && (p_rcb->ucd.state != L2C_UCD_STATE_UNUSED))
      return (true);
  }

  /* delete master rcb for UCD */
  p_rcb = l2cu_find_rcb_by_psm(L2C_UCD_RCB_ID);
  if (p_rcb != NULL) {
    l2cu_release_rcb(p_rcb);
  }

  /* delete CCB for UCD */
  p_ccb = l2cb.ccb_pool;
  for (xx = 0; xx < MAX_L2CAP_CHANNELS; xx++) {
    if ((p_ccb->in_use) && (p_ccb->local_cid == L2CAP_CONNECTIONLESS_CID)) {
      l2cu_release_ccb(p_ccb);
    }
    p_ccb++;
  }

  return (true);
}

/*******************************************************************************
 *
 *  Function        L2CA_UcdDiscover
 *
 *  Description     Discover UCD of remote device.
 *
 *  Parameters:     PSM
 *                  BD_ADDR of remote device
 *                  info_type : L2CAP_UCD_INFO_TYPE_RECEPTION
 *                              L2CAP_UCD_INFO_TYPE_MTU
 *
 *
 *  Return value:   true if successs
 *
 ******************************************************************************/
bool L2CA_UcdDiscover(uint16_t psm, const RawAddress& rem_bda,
                      uint8_t info_type) {
  tL2C_LCB* p_lcb;
  tL2C_CCB* p_ccb;
  tL2C_RCB* p_rcb;

  L2CAP_TRACE_API(
      "L2CA_UcdDiscover()  PSM: 0x%04x  BDA: %08x%04x, InfoType=0x%02x", psm,
      (rem_bda[0] << 24) + (rem_bda[1] << 16) + (rem_bda[2] << 8) + rem_bda[3],
      (rem_bda[4] << 8) + rem_bda[5], info_type);

  /* Fail if the PSM is not registered */
  if (((p_rcb = l2cu_find_rcb_by_psm(psm)) == NULL) ||
      (p_rcb->ucd.state == L2C_UCD_STATE_UNUSED)) {
    L2CAP_TRACE_WARNING("L2CAP - no RCB for L2CA_UcdDiscover, PSM: 0x%04x",
                        psm);
    return (false);
  }

  /* First, see if we already have a link to the remote */
  /* then find the channel control block for UCD. */
  if (((p_lcb = l2cu_find_lcb_by_bd_addr(rem_bda, BT_TRANSPORT_BR_EDR)) ==
       NULL) ||
      ((p_ccb = l2cu_find_ccb_by_cid(p_lcb, L2CAP_CONNECTIONLESS_CID)) ==
       NULL)) {
    if (l2c_ucd_connect(rem_bda) == false) {
      return (false);
    }
  }

  /* set waiting flags in rcb */

  if (info_type & L2CAP_UCD_INFO_TYPE_RECEPTION)
    p_rcb->ucd.state |= L2C_UCD_STATE_W4_RECEPTION;

  if (info_type & L2CAP_UCD_INFO_TYPE_MTU)
    p_rcb->ucd.state |= L2C_UCD_STATE_W4_MTU;

  /* if link is already established */
  if ((p_lcb) && (p_lcb->link_state == LST_CONNECTED)) {
    if (!p_ccb) {
      p_ccb = l2cu_find_ccb_by_cid(p_lcb, L2CAP_CONNECTIONLESS_CID);
    }
    l2c_ucd_check_pending_info_req(p_ccb);
  }
  return (true);
}

/*******************************************************************************
 *
 *  Function        L2CA_UcdDataWrite
 *
 *  Description     Send UCD to remote device
 *
 *  Parameters:     PSM
 *                  BD Address of remote
 *                  Pointer to buffer of type BT_HDR
 *                  flags : L2CAP_FLUSHABLE_CH_BASED
 *                          L2CAP_FLUSHABLE_PKT
 *                          L2CAP_NON_FLUSHABLE_PKT
 *
 * Return value     L2CAP_DW_SUCCESS, if data accepted
 *                  L2CAP_DW_FAILED,  if error
 *
 ******************************************************************************/
uint16_t L2CA_UcdDataWrite(uint16_t psm, const RawAddress& rem_bda,
                           BT_HDR* p_buf, uint16_t flags) {
  tL2C_LCB* p_lcb;
  tL2C_CCB* p_ccb;
  tL2C_RCB* p_rcb;
  uint8_t* p;

  L2CAP_TRACE_API(
      "L2CA_UcdDataWrite()  PSM: 0x%04x  BDA: %08x%04x", psm,
      (rem_bda[0] << 24) + (rem_bda[1] << 16) + (rem_bda[2] << 8) + rem_bda[3],
      (rem_bda[4] << 8) + rem_bda[5]);

  /* Fail if the PSM is not registered */
  if (((p_rcb = l2cu_find_rcb_by_psm(psm)) == NULL) ||
      (p_rcb->ucd.state == L2C_UCD_STATE_UNUSED)) {
    L2CAP_TRACE_WARNING("L2CAP - no RCB for L2CA_UcdDataWrite, PSM: 0x%04x",
                        psm);
    osi_free(p_buf);
    return (L2CAP_DW_FAILED);
  }

  /* First, see if we already have a link to the remote */
  /*  then find the channel control block for UCD */
  if (((p_lcb = l2cu_find_lcb_by_bd_addr(rem_bda, BT_TRANSPORT_BR_EDR)) ==
       NULL) ||
      ((p_ccb = l2cu_find_ccb_by_cid(p_lcb, L2CAP_CONNECTIONLESS_CID)) ==
       NULL)) {
    if (l2c_ucd_connect(rem_bda) == false) {
      osi_free(p_buf);
      return (L2CAP_DW_FAILED);
    }

    /* If we still don't have lcb and ccb after connect attempt, then can't
     * proceed */
    if (((p_lcb = l2cu_find_lcb_by_bd_addr(rem_bda, BT_TRANSPORT_BR_EDR)) ==
         NULL) ||
        ((p_ccb = l2cu_find_ccb_by_cid(p_lcb, L2CAP_CONNECTIONLESS_CID)) ==
         NULL)) {
      osi_free(p_buf);
      return (L2CAP_DW_FAILED);
    }
  }

  /* write PSM */
  p_buf->offset -= L2CAP_UCD_OVERHEAD;
  p_buf->len += L2CAP_UCD_OVERHEAD;
  p = (uint8_t*)(p_buf + 1) + p_buf->offset;

  UINT16_TO_STREAM(p, psm);

  /* UCD MTU check */
  if ((p_lcb->ucd_mtu) && (p_buf->len > p_lcb->ucd_mtu)) {
    L2CAP_TRACE_WARNING(
        "L2CAP - Handle: 0x%04x  UCD bigger than peer's UCD mtu size cannot be "
        "sent",
        p_lcb->handle);
    osi_free(p_buf);
    return (L2CAP_DW_FAILED);
  }

  /* If already congested, do not accept any more packets */
  if (p_ccb->cong_sent) {
    L2CAP_TRACE_ERROR(
        "L2CAP - Handle: 0x%04x UCD cannot be sent, already congested count: "
        "%u  buff_quota: %u",
        p_lcb->handle, (fixed_queue_length(p_ccb->xmit_hold_q) +
                        fixed_queue_length(p_lcb->ucd_out_sec_pending_q)),
        p_ccb->buff_quota);

    osi_free(p_buf);
    return (L2CAP_DW_FAILED);
  }

  /* channel based, packet based flushable or non-flushable */
  p_buf->layer_specific = flags;

  l2c_csm_execute(p_ccb, L2CEVT_L2CA_DATA_WRITE, p_buf);

  if (p_ccb->cong_sent)
    return (L2CAP_DW_CONGESTED);
  else
    return (L2CAP_DW_SUCCESS);
}

/*******************************************************************************
 *
 *  Function        L2CA_UcdSetIdleTimeout
 *
 *  Description     Set UCD Idle timeout.
 *
 *  Parameters:     BD Addr
 *                  Timeout in second
 *
 *  Return value:   true if successs
 *
 ******************************************************************************/
bool L2CA_UcdSetIdleTimeout(const RawAddress& rem_bda, uint16_t timeout) {
  tL2C_LCB* p_lcb;
  tL2C_CCB* p_ccb;

  L2CAP_TRACE_API(
      "L2CA_UcdSetIdleTimeout()  Timeout: 0x%04x  BDA: %08x%04x", timeout,
      (rem_bda[0] << 24) + (rem_bda[1] << 16) + (rem_bda[2] << 8) + rem_bda[3],
      (rem_bda[4] << 8) + rem_bda[5]);

  /* First, see if we already have a link to the remote */
  /* then find the channel control block. */
  if (((p_lcb = l2cu_find_lcb_by_bd_addr(rem_bda, BT_TRANSPORT_BR_EDR)) ==
       NULL) ||
      ((p_ccb = l2cu_find_ccb_by_cid(p_lcb, L2CAP_CONNECTIONLESS_CID)) ==
       NULL)) {
    L2CAP_TRACE_WARNING("L2CAP - no UCD channel");
    return (false);
  } else {
    p_ccb->fixed_chnl_idle_tout = timeout;
    return (true);
  }
}

/*******************************************************************************
 *
 * Function         L2CA_UCDSetTxPriority
 *
 * Description      Sets the transmission priority for a connectionless channel.
 *
 * Returns          true if a valid channel, else false
 *
 ******************************************************************************/
bool L2CA_UCDSetTxPriority(const RawAddress& rem_bda,
                           tL2CAP_CHNL_PRIORITY priority) {
  tL2C_LCB* p_lcb;
  tL2C_CCB* p_ccb;

  L2CAP_TRACE_API(
      "L2CA_UCDSetTxPriority()  priority: 0x%02x  BDA: %08x%04x", priority,
      (rem_bda[0] << 24) + (rem_bda[1] << 16) + (rem_bda[2] << 8) + rem_bda[3],
      (rem_bda[4] << 8) + rem_bda[5]);

  p_lcb = l2cu_find_lcb_by_bd_addr(rem_bda, BT_TRANSPORT_BR_EDR);
  if (p_lcb == NULL) {
    L2CAP_TRACE_WARNING("L2CAP - no LCB for L2CA_UCDSetTxPriority");
    return (false);
  }

  /* Find the channel control block */
  p_ccb = l2cu_find_ccb_by_cid(p_lcb, L2CAP_CONNECTIONLESS_CID);
  if (p_ccb == NULL) {
    L2CAP_TRACE_WARNING("L2CAP - no CCB for L2CA_UCDSetTxPriority");
    return (false);
  }

  /* it will update the order of CCB in LCB by priority and update round robin
   * service variables */
  l2cu_change_pri_ccb(p_ccb, priority);

  return (true);
}

/*******************************************************************************
 *
 *  Function        l2c_ucd_connect
 *
 *  Description     Connect UCD to remote device.
 *
 *  Parameters:     BD_ADDR of remote device
 *
 *  Return value:   true if successs
 *
 ******************************************************************************/
static bool l2c_ucd_connect(const RawAddress& rem_bda) {
  tL2C_LCB* p_lcb;
  tL2C_CCB* p_ccb;
  tL2C_RCB* p_rcb;

  L2CAP_TRACE_DEBUG(
      "l2c_ucd_connect()  BDA: %08x%04x",
      (rem_bda[0] << 24) + (rem_bda[1] << 16) + (rem_bda[2] << 8) + rem_bda[3],
      (rem_bda[4] << 8) + rem_bda[5]);

  /* Fail if we have not established communications with the controller */
  if (!BTM_IsDeviceUp()) {
    L2CAP_TRACE_WARNING("l2c_ucd_connect - BTU not ready");
    return (false);
  }

  /* First, see if we already have a link to the remote */
  p_lcb = l2cu_find_lcb_by_bd_addr(rem_bda, BT_TRANSPORT_BR_EDR);
  if (p_lcb == NULL) {
    /* No link. Get an LCB and start link establishment */
    if (((p_lcb = l2cu_allocate_lcb(rem_bda, false, BT_TRANSPORT_BR_EDR)) ==
         NULL) ||
        (l2cu_create_conn(p_lcb, BT_TRANSPORT_BR_EDR) == false)) {
      L2CAP_TRACE_WARNING("L2CAP - conn not started l2c_ucd_connect");
      return (false);
    }
  } else if (p_lcb->info_rx_bits & (1 << L2CAP_EXTENDED_FEATURES_INFO_TYPE)) {
    if (!(p_lcb->peer_ext_fea & L2CAP_EXTFEA_UCD_RECEPTION)) {
      L2CAP_TRACE_WARNING(
          "L2CAP - UCD is not supported by peer, l2c_ucd_connect");
      return (false);
    }
  }

  /* Find the channel control block. */
  p_ccb = l2cu_find_ccb_by_cid(p_lcb, L2CAP_CONNECTIONLESS_CID);
  if (p_ccb == NULL) {
    /* Allocate a channel control block */
    p_ccb = l2cu_allocate_ccb(p_lcb, 0);
    if (p_ccb == NULL) {
      L2CAP_TRACE_WARNING("L2CAP - no CCB for l2c_ucd_connect");
      return (false);
    } else {
      /* Set CID for the connection */
      p_ccb->local_cid = L2CAP_CONNECTIONLESS_CID;
      p_ccb->remote_cid = L2CAP_CONNECTIONLESS_CID;

      /* Set the default idle timeout value to use */
      p_ccb->fixed_chnl_idle_tout = L2CAP_UCD_IDLE_TIMEOUT;

      /* Set the default channel priority value to use */
      l2cu_change_pri_ccb(p_ccb, L2CAP_UCD_CH_PRIORITY);

      p_rcb = l2cu_find_rcb_by_psm(L2C_UCD_RCB_ID);
      if (p_rcb == NULL) {
        L2CAP_TRACE_WARNING("L2CAP - no UCD registered, l2c_ucd_connect");
        return (false);
      }
      /* Save UCD registration info */
      p_ccb->p_rcb = p_rcb;

      /* There is no configuration, so if the link is up, the channel is up */
      if (p_lcb->link_state == LST_CONNECTED) {
        p_ccb->chnl_state = CST_OPEN;
      }
    }
  }

  return (true);
}

/*******************************************************************************
 *
 *  Function        l2c_ucd_delete_sec_pending_q
 *
 * Description      discard all of UCD packets in security pending queue
 *
 * Returns          None
 *
 ******************************************************************************/
void l2c_ucd_delete_sec_pending_q(tL2C_LCB* p_lcb) {
  /* clean up any security pending UCD */
  while (!fixed_queue_is_empty(p_lcb->ucd_out_sec_pending_q))
    osi_free(fixed_queue_try_dequeue(p_lcb->ucd_out_sec_pending_q));
  fixed_queue_free(p_lcb->ucd_out_sec_pending_q, NULL);
  p_lcb->ucd_out_sec_pending_q = NULL;

  while (!fixed_queue_is_empty(p_lcb->ucd_in_sec_pending_q))
    osi_free(fixed_queue_try_dequeue(p_lcb->ucd_in_sec_pending_q));
  fixed_queue_free(p_lcb->ucd_in_sec_pending_q);
  p_lcb->ucd_in_sec_pending_q = NULL;
}

/*******************************************************************************
 *
 *  Function        l2c_ucd_check_pending_info_req
 *
 * Description      check if any application is waiting for UCD information
 *
 *  Return          true if any pending UCD info request
 *
 ******************************************************************************/
bool l2c_ucd_check_pending_info_req(tL2C_CCB* p_ccb) {
  tL2C_RCB* p_rcb = &l2cb.rcb_pool[0];
  uint16_t xx;
  bool pending = false;

  if (p_ccb == NULL) {
    L2CAP_TRACE_ERROR("L2CAP - NULL p_ccb in l2c_ucd_check_pending_info_req");
    return (false);
  }

  for (xx = 0; xx < MAX_L2CAP_CLIENTS; xx++, p_rcb++) {
    if (p_rcb->in_use) {
      /* if application is waiting UCD reception info */
      if (p_rcb->ucd.state & L2C_UCD_STATE_W4_RECEPTION) {
        /* if this information is available */
        if (p_ccb->p_lcb->info_rx_bits &
            (1 << L2CAP_EXTENDED_FEATURES_INFO_TYPE)) {
          if (!(p_ccb->p_lcb->peer_ext_fea & L2CAP_EXTFEA_UCD_RECEPTION)) {
            L2CAP_TRACE_WARNING(
                "L2CAP - UCD is not supported by peer, "
                "l2c_ucd_check_pending_info_req");

            l2c_ucd_delete_sec_pending_q(p_ccb->p_lcb);
            l2cu_release_ccb(p_ccb);
          }

          p_ccb->p_rcb->ucd.cb_info.pL2CA_UCD_Discover_Cb(
              p_ccb->p_lcb->remote_bd_addr, L2CAP_UCD_INFO_TYPE_RECEPTION,
              p_ccb->p_lcb->peer_ext_fea & L2CAP_EXTFEA_UCD_RECEPTION);
        } else {
          pending = true;
          if (p_ccb->p_lcb->w4_info_rsp == false) {
            l2cu_send_peer_info_req(p_ccb->p_lcb,
                                    L2CAP_EXTENDED_FEATURES_INFO_TYPE);
          }
        }
      }

      /* if application is waiting for UCD MTU */
      if (p_rcb->ucd.state & L2C_UCD_STATE_W4_MTU) {
        /* if this information is available */
        if (p_ccb->p_lcb->info_rx_bits & (1 << L2CAP_CONNLESS_MTU_INFO_TYPE)) {
          p_ccb->p_rcb->ucd.cb_info.pL2CA_UCD_Discover_Cb(
              p_ccb->p_lcb->remote_bd_addr, L2CAP_UCD_INFO_TYPE_MTU,
              p_ccb->p_lcb->ucd_mtu);
        } else {
          pending = true;
          if (p_ccb->p_lcb->w4_info_rsp == false) {
            l2cu_send_peer_info_req(p_ccb->p_lcb, L2CAP_CONNLESS_MTU_INFO_TYPE);
          }
        }
      }
    }
  }
  return (pending);
}

/*******************************************************************************
 *
 *  Function        l2c_ucd_enqueue_pending_out_sec_q
 *
 *  Description     enqueue outgoing UCD packet into security pending queue
 *                  and check congestion
 *
 *  Return          None
 *
 ******************************************************************************/
void l2c_ucd_enqueue_pending_out_sec_q(tL2C_CCB* p_ccb, void* p_data) {
  fixed_queue_enqueue(p_ccb->p_lcb->ucd_out_sec_pending_q, p_data);
  l2cu_check_channel_congestion(p_ccb);
}

/*******************************************************************************
 *
 *  Function        l2c_ucd_check_pending_out_sec_q
 *
 *  Description     check outgoing security
 *
 *  Return          true if any UCD packet for security
 *
 ******************************************************************************/
bool l2c_ucd_check_pending_out_sec_q(tL2C_CCB* p_ccb) {
  BT_HDR* p_buf =
      (BT_HDR*)fixed_queue_try_peek_first(p_ccb->p_lcb->ucd_out_sec_pending_q);

  if (p_buf != NULL) {
    uint16_t psm;
    uint8_t* p = (uint8_t*)(p_buf + 1) + p_buf->offset;

    STREAM_TO_UINT16(psm, p)

    p_ccb->chnl_state = CST_ORIG_W4_SEC_COMP;
    btm_sec_l2cap_access_req(p_ccb->p_lcb->remote_bd_addr, psm,
                             p_ccb->p_lcb->handle, CONNLESS_ORIG,
                             &l2c_link_sec_comp, p_ccb);

    return (true);
  }
  return (false);
}

/*******************************************************************************
 *
 *  Function        l2c_ucd_send_pending_out_sec_q
 *
 *  Description     dequeue UCD packet from security pending queue and
 *                  enqueue it into CCB
 *
 *  Return          None
 *
 ******************************************************************************/
void l2c_ucd_send_pending_out_sec_q(tL2C_CCB* p_ccb) {
  BT_HDR* p_buf =
      (BT_HDR*)fixed_queue_try_dequeue(p_ccb->p_lcb->ucd_out_sec_pending_q);

  if (p_buf != NULL) {
    l2c_enqueue_peer_data(p_ccb, (BT_HDR*)p_buf);
    l2c_link_check_send_pkts(p_ccb->p_lcb, NULL, NULL);
  }
}

/*******************************************************************************
 *
 *  Function        l2c_ucd_discard_pending_out_sec_q
 *
 *  Description     dequeue UCD packet from security pending queue and
 *                  discard it.
 *
 *  Return          None
 *
 ******************************************************************************/
void l2c_ucd_discard_pending_out_sec_q(tL2C_CCB* p_ccb) {
  BT_HDR* p_buf =
      (BT_HDR*)fixed_queue_try_dequeue(p_ccb->p_lcb->ucd_out_sec_pending_q);

  /* we may need to report to application */
  osi_free(p_buf);
}

/*******************************************************************************
 *
 *  Function        l2c_ucd_check_pending_in_sec_q
 *
 *  Description     check incoming security
 *
 *  Return          true if any UCD packet for security
 *
 ******************************************************************************/
bool l2c_ucd_check_pending_in_sec_q(tL2C_CCB* p_ccb) {
  BT_HDR* p_buf =
      (BT_HDR*)fixed_queue_try_dequeue(p_ccb->p_lcb->ucd_in_sec_pending_q);

  if (p_buf != NULL) {
    uint16_t psm;
    uint8_t* p = (uint8_t*)(p_buf + 1) + p_buf->offset;
    STREAM_TO_UINT16(psm, p)

    p_ccb->chnl_state = CST_TERM_W4_SEC_COMP;
    btm_sec_l2cap_access_req(p_ccb->p_lcb->remote_bd_addr, psm,
                             p_ccb->p_lcb->handle, CONNLESS_TERM,
                             &l2c_link_sec_comp, p_ccb);

    return (true);
  }
  return (false);
}

/*******************************************************************************
 *
 *  Function        l2c_ucd_send_pending_in_sec_q
 *
 *  Description     dequeue UCD packet from security pending queue and
 *                  send it to application
 *
 *  Return          None
 *
 ******************************************************************************/
void l2c_ucd_send_pending_in_sec_q(tL2C_CCB* p_ccb) {
  BT_HDR* p_buf =
      (BT_HDR*)fixed_queue_try_dequeue(p_ccb->p_lcb->ucd_in_sec_pending_q)

          if (p_buf != NULL) {
    p_ccb->p_rcb->ucd.cb_info.pL2CA_UCD_Data_Cb(p_ccb->p_lcb->remote_bd_addr,
                                                (BT_HDR*)p_buf);
  }
}

/*******************************************************************************
 *
 *  Function        l2c_ucd_discard_pending_in_sec_q
 *
 *  Description     dequeue UCD packet from security pending queue and
 *                  discard it.
 *
 *  Return          None
 *
 ******************************************************************************/
void l2c_ucd_discard_pending_in_sec_q(tL2C_CCB* p_ccb) {
  BT_HDR* p_buf =
      (BT_HDR*)fixed_queue_try_dequeue(p_ccb->p_lcb->ucd_in_sec_pending_q);
  osi_free(p_buf);
}

/*******************************************************************************
 *
 *  Function        l2c_ucd_check_rx_pkts
 *
 *  Description     Check if UCD reception is registered.
 *                  Process received UCD packet if application is expecting.
 *
 *  Return          true if UCD reception is registered
 *
 ******************************************************************************/
bool l2c_ucd_check_rx_pkts(tL2C_LCB* p_lcb, BT_HDR* p_msg) {
  tL2C_CCB* p_ccb;
  tL2C_RCB* p_rcb;

  if (((p_ccb = l2cu_find_ccb_by_cid(p_lcb, L2CAP_CONNECTIONLESS_CID)) !=
       NULL) ||
      ((p_rcb = l2cu_find_rcb_by_psm(L2C_UCD_RCB_ID)) != NULL)) {
    if (p_ccb == NULL) {
      /* Allocate a channel control block */
      p_ccb = l2cu_allocate_ccb(p_lcb, 0);
      if (p_ccb == NULL) {
        L2CAP_TRACE_WARNING("L2CAP - no CCB for UCD reception");
        osi_free(p_msg);
        return true;
      } else {
        /* Set CID for the connection */
        p_ccb->local_cid = L2CAP_CONNECTIONLESS_CID;
        p_ccb->remote_cid = L2CAP_CONNECTIONLESS_CID;

        /* Set the default idle timeout value to use */
        p_ccb->fixed_chnl_idle_tout = L2CAP_UCD_IDLE_TIMEOUT;

        /* Set the default channel priority value to use */
        l2cu_change_pri_ccb(p_ccb, L2CAP_UCD_CH_PRIORITY);

        /* Save registration info */
        p_ccb->p_rcb = p_rcb;

        p_ccb->chnl_state = CST_OPEN;
      }
    }
    l2c_csm_execute(p_ccb, L2CEVT_L2CAP_DATA, p_msg);
    return true;
  } else
    return false;
}

/*******************************************************************************
 *
 *  Function        l2c_ucd_process_event
 *
 *  Description     This is called from main state machine when LCID is
 *                  connectionless. Process the event if it is for UCD.
 *
 *  Return          true if the event is consumed by UCD
 *                  false if the event needs to be processed by the main state
 *                        machine
 *
 ******************************************************************************/
bool l2c_ucd_process_event(tL2C_CCB* p_ccb, uint16_t event, void* p_data) {
  /* if the event is not processed by this function, this variable will be set
   * to false */
  bool done = true;

  switch (p_ccb->chnl_state) {
    case CST_CLOSED:
      switch (event) {
        case L2CEVT_LP_CONNECT_CFM: /* Link came up         */
          /* check if waiting for UCD info */
          if (!l2c_ucd_check_pending_info_req(p_ccb)) {
            /* check if any outgoing UCD packet is waiting security check */
            if (!l2c_ucd_check_pending_out_sec_q(p_ccb)) {
              p_ccb->chnl_state = CST_OPEN;
            }
          }
          break;

        case L2CEVT_L2CAP_DATA: /* Peer data packet rcvd    */
          fixed_queue_enqueue(p_ccb->p_lcb->ucd_in_sec_pending_q, p_data);
          break;

        case L2CEVT_L2CA_DATA_WRITE: /* Upper layer data to send */
          l2c_ucd_enqueue_pending_out_sec_q(p_ccb, p_data);
          break;

        case L2CEVT_L2CAP_INFO_RSP:
          /* check if waiting for UCD info */
          if (!l2c_ucd_check_pending_info_req(p_ccb)) {
            /* check if any outgoing UCD packet is waiting security check */
            if (!l2c_ucd_check_pending_out_sec_q(p_ccb)) {
              p_ccb->chnl_state = CST_OPEN;
            }
          }
          break;

        default:
          done = false; /* main state machine continues to process event */
          break;
      }
      break;

    case CST_ORIG_W4_SEC_COMP:
      switch (event) {
        case L2CEVT_SEC_RE_SEND_CMD: /* BTM has enough info to proceed */
          /* check if any outgoing UCD packet is waiting security check */
          if (!l2c_ucd_check_pending_out_sec_q(p_ccb)) {
            p_ccb->chnl_state = CST_OPEN;
          }
          break;

        case L2CEVT_SEC_COMP: /* Security completed success */
          p_ccb->chnl_state = CST_OPEN;
          l2c_ucd_send_pending_out_sec_q(p_ccb);

          if (!fixed_queue_is_empty(p_ccb->p_lcb->ucd_out_sec_pending_q)) {
            /* start a timer to send next UCD packet in OPEN state */
            /* it will prevent stack overflow */
            alarm_set_on_queue(p_ccb->l2c_ccb_timer, 0, l2c_ccb_timer_timeout,
                               p_ccb, btu_general_alarm_queue);
          } else {
            /* start a timer for idle timeout of UCD */
            period_ms_t timeout_ms = p_ccb->fixed_chnl_idle_tout * 1000;
            alarm_set_on_queue(p_ccb->l2c_ccb_timer, timeout_ms,
                               l2c_ccb_timer_timeout, p_ccb,
                               btu_general_alarm_queue);
          }
          break;

        case L2CEVT_SEC_COMP_NEG:
          p_ccb->chnl_state = CST_OPEN;
          l2c_ucd_discard_pending_out_sec_q(p_ccb);

          /* start a timer for idle timeout of UCD */
          period_ms_t timeout_ms = p_ccb->fixed_chnl_idle_tout * 1000;
          alarm_set_on_queue(p_ccb->l2c_ccb_timer, timeout_ms,
                             l2c_ccb_timer_timeout, p_ccb,
                             btu_general_alarm_queue);
          break;

        case L2CEVT_L2CA_DATA_WRITE: /* Upper layer data to send */
          l2c_ucd_enqueue_pending_out_sec_q(p_ccb, p_data);
          break;

        case L2CEVT_L2CAP_DATA: /* Peer data packet rcvd    */
          fixed_queue_enqueue(p_ccb->p_lcb->ucd_in_sec_pending_q, p_data);
          break;

        case L2CEVT_L2CAP_INFO_RSP:
          /* check if waiting for UCD info */
          l2c_ucd_check_pending_info_req(p_ccb);
          break;

        default:
          done = false; /* main state machine continues to process event */
          break;
      }
      break;

    case CST_TERM_W4_SEC_COMP:
      switch (event) {
        case L2CEVT_SEC_COMP:
          p_ccb->chnl_state = CST_OPEN;
          l2c_ucd_send_pending_in_sec_q(p_ccb);

          if (!fixed_queue_is_empty(p_ccb->p_lcb->ucd_in_sec_pending_q)) {
            /* start a timer to check next UCD packet in OPEN state */
            /* it will prevent stack overflow */
            alarm_set_on_queue(p_ccb->l2c_ccb_timer, 0, l2c_ccb_timer_timeout,
                               p_ccb, btu_general_alarm_queue);
          } else {
            /* start a timer for idle timeout of UCD */
            period_ms_t timeout_ms = p_ccb->fixed_chnl_idle_tout * 1000;
            alarm_set_on_queue(p_ccb->l2c_ccb_timer, timeout_ms,
                               l2c_ccb_timer_timeout, p_ccb,
                               btu_general_alarm_queue);
          }
          break;

        case L2CEVT_SEC_COMP_NEG:
          if (((tL2C_CONN_INFO*)p_data)->status == BTM_DELAY_CHECK) {
            done = false;
            break;
          }
          p_ccb->chnl_state = CST_OPEN;
          l2c_ucd_discard_pending_in_sec_q(p_ccb);

          /* start a timer for idle timeout of UCD */
          period_ms_t timeout_ms = p_ccb->fixed_chnl_idle_tout * 1000;
          alarm_set_on_queue(p_ccb->l2c_ccb_timer, timeout_ms,
                             l2c_ccb_timer_timeout, p_ccb,
                             btu_general_alarm_queue);
          break;

        case L2CEVT_L2CA_DATA_WRITE: /* Upper layer data to send */
          l2c_ucd_enqueue_pending_out_sec_q(p_ccb, p_data);
          break;

        case L2CEVT_L2CAP_DATA: /* Peer data packet rcvd    */
          fixed_queue_enqueue(p_ccb->p_lcb->ucd_in_sec_pending_q, p_data);
          break;

        case L2CEVT_SEC_RE_SEND_CMD: /* BTM has enough info to proceed */
          /* check if any incoming UCD packet is waiting security check */
          if (!l2c_ucd_check_pending_in_sec_q(p_ccb)) {
            p_ccb->chnl_state = CST_OPEN;
          }
          break;

        case L2CEVT_L2CAP_INFO_RSP:
          /* check if waiting for UCD info */
          l2c_ucd_check_pending_info_req(p_ccb);
          break;

        default:
          done = false; /* main state machine continues to process event */
          break;
      }
      break;

    case CST_OPEN:
      switch (event) {
        case L2CEVT_L2CAP_DATA: /* Peer data packet rcvd    */
          /* stop idle timer of UCD */
          alarm_cancel(p_ccb->l2c_ccb_timer);

          fixed_queue_enqueue(p_ccb->p_lcb->ucd_in_sec_pending_q, p_data);
          l2c_ucd_check_pending_in_sec_q(p_ccb);
          break;

        case L2CEVT_L2CA_DATA_WRITE: /* Upper layer data to send */
          /* stop idle timer of UCD */
          alarm_cancel(p_ccb->l2c_ccb_timer);

          l2c_ucd_enqueue_pending_out_sec_q(p_ccb, p_data);

          /* success changes state, failure stays in current state */
          l2c_ucd_check_pending_out_sec_q(p_ccb);
          break;

        case L2CEVT_TIMEOUT:
          /* check if any UCD packet is waiting security check */
          if ((!l2c_ucd_check_pending_in_sec_q(p_ccb)) &&
              (!l2c_ucd_check_pending_out_sec_q(p_ccb))) {
            l2cu_release_ccb(p_ccb);
          }
          break;

        case L2CEVT_L2CAP_INFO_RSP:
          /* check if waiting for UCD info */
          l2c_ucd_check_pending_info_req(p_ccb);
          break;

        default:
          done = false; /* main state machine continues to process event */
          break;
      }
      break;

    default:
      done = false; /* main state machine continues to process event */
      break;
  }

  return done;
}
#endif /* (L2CAP_UCD_INCLUDED == TRUE) */