xref: /system/nfc/src/nfc/llcp/llcp_api.cc

/******************************************************************************
 *
 *  Copyright (C) 2010-2014 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 LLCP API code
 *
 ******************************************************************************/

#include "llcp_api.h"
#include <string.h>
#include "bt_types.h"
#include "gki.h"
#include "llcp_defs.h"
#include "llcp_int.h"
#include "nfc_target.h"

#if (LLCP_TEST_INCLUDED == TRUE) /* this is for LLCP testing */

tLLCP_TEST_PARAMS llcp_test_params = {
    LLCP_VERSION_VALUE, 0, /* not override */
};

/*******************************************************************************
**
** Function         LLCP_SetTestParams
**
** Description      Set test parameters for LLCP
**
**
** Returns          void
**
*******************************************************************************/
void LLCP_SetTestParams(uint8_t version, uint16_t wks) {
  LLCP_TRACE_API2("LLCP_SetTestParams () version:0x%02X, wks:0x%04X", version,
                  wks);

  if (version != 0xFF) llcp_test_params.version = version;

  if (wks != 0xFFFF) llcp_test_params.wks = wks;
}
#endif

/*******************************************************************************
**
** Function         LLCP_RegisterDtaCback
**
** Description      Register callback function for LLCP DTA testing
**
**
** Returns          void
**
*******************************************************************************/
void LLCP_RegisterDtaCback(tLLCP_DTA_CBACK* p_dta_cback) {
  LLCP_TRACE_API1("%s", __func__);

  llcp_cb.p_dta_cback = p_dta_cback;
}

/*******************************************************************************
**
** Function         LLCP_SetConfig
**
** Description      Set configuration parameters for LLCP
**                  - Local Link MIU
**                  - Option parameter
**                  - Response Waiting Time Index
**                  - Local Link Timeout
**                  - Inactivity Timeout as initiator role
**                  - Inactivity Timeout as target role
**                  - Delay SYMM response
**                  - Data link connection timeout
**                  - Delay timeout to send first PDU as initiator
**
** Returns          void
**
*******************************************************************************/
void LLCP_SetConfig(uint16_t link_miu, uint8_t opt, uint8_t wt,
                    uint16_t link_timeout, uint16_t inact_timeout_init,
                    uint16_t inact_timeout_target, uint16_t symm_delay,
                    uint16_t data_link_timeout,
                    uint16_t delay_first_pdu_timeout) {
  LLCP_TRACE_API4(
      "LLCP_SetConfig () link_miu:%d, opt:0x%02X, wt:%d, link_timeout:%d",
      link_miu, opt, wt, link_timeout);
  LLCP_TRACE_API4(
      "                 inact_timeout (init:%d,target:%d), symm_delay:%d, "
      "data_link_timeout:%d",
      inact_timeout_init, inact_timeout_target, symm_delay, data_link_timeout);
  LLCP_TRACE_API1("                 delay_first_pdu_timeout:%d",
                  delay_first_pdu_timeout);

  if (link_miu < LLCP_DEFAULT_MIU) {
    LLCP_TRACE_ERROR1(
        "LLCP_SetConfig (): link_miu shall not be smaller than "
        "LLCP_DEFAULT_MIU (%d)",
        LLCP_DEFAULT_MIU);
    link_miu = LLCP_DEFAULT_MIU;
  } else if (link_miu > LLCP_MAX_MIU) {
    LLCP_TRACE_ERROR1(
        "LLCP_SetConfig (): link_miu shall not be bigger than LLCP_MAX_MIU "
        "(%d)",
        LLCP_MAX_MIU);
    link_miu = LLCP_MAX_MIU;
  }

  /* if Link MIU is bigger than GKI buffer */
  if (link_miu > LLCP_MIU) {
    LLCP_TRACE_ERROR1(
        "LLCP_SetConfig (): link_miu shall not be bigger than LLCP_MIU (%d)",
        LLCP_MIU);
    llcp_cb.lcb.local_link_miu = LLCP_MIU;
  } else
    llcp_cb.lcb.local_link_miu = link_miu;

  llcp_cb.lcb.local_opt = opt;
  llcp_cb.lcb.local_wt = wt;

  if (link_timeout < LLCP_LTO_UNIT) {
    LLCP_TRACE_ERROR1(
        "LLCP_SetConfig (): link_timeout shall not be smaller than "
        "LLCP_LTO_UNIT (%d ms)",
        LLCP_LTO_UNIT);
    llcp_cb.lcb.local_lto = LLCP_DEFAULT_LTO_IN_MS;
  } else if (link_timeout > LLCP_MAX_LTO_IN_MS) {
    LLCP_TRACE_ERROR1(
        "LLCP_SetConfig (): link_timeout shall not be bigger than "
        "LLCP_MAX_LTO_IN_MS (%d ms)",
        LLCP_MAX_LTO_IN_MS);
    llcp_cb.lcb.local_lto = LLCP_MAX_LTO_IN_MS;
  } else
    llcp_cb.lcb.local_lto = link_timeout;

  llcp_cb.lcb.inact_timeout_init = inact_timeout_init;
  llcp_cb.lcb.inact_timeout_target = inact_timeout_target;
  llcp_cb.lcb.symm_delay = symm_delay;
  llcp_cb.lcb.data_link_timeout = data_link_timeout;
  llcp_cb.lcb.delay_first_pdu_timeout = delay_first_pdu_timeout;
}

/*******************************************************************************
**
** Function         LLCP_GetConfig
**
** Description      Get configuration parameters for LLCP
**                  - Local Link MIU
**                  - Option parameter
**                  - Response Waiting Time Index
**                  - Local Link Timeout
**                  - Inactivity Timeout as initiator role
**                  - Inactivity Timeout as target role
**                  - Delay SYMM response
**                  - Data link connection timeout
**                  - Delay timeout to send first PDU as initiator
**
** Returns          void
**
*******************************************************************************/
void LLCP_GetConfig(uint16_t* p_link_miu, uint8_t* p_opt, uint8_t* p_wt,
                    uint16_t* p_link_timeout, uint16_t* p_inact_timeout_init,
                    uint16_t* p_inact_timeout_target, uint16_t* p_symm_delay,
                    uint16_t* p_data_link_timeout,
                    uint16_t* p_delay_first_pdu_timeout) {
  *p_link_miu = llcp_cb.lcb.local_link_miu;
  *p_opt = llcp_cb.lcb.local_opt;
  *p_wt = llcp_cb.lcb.local_wt;
  *p_link_timeout = llcp_cb.lcb.local_lto;
  *p_inact_timeout_init = llcp_cb.lcb.inact_timeout_init;
  *p_inact_timeout_target = llcp_cb.lcb.inact_timeout_target;
  *p_symm_delay = llcp_cb.lcb.symm_delay;
  *p_data_link_timeout = llcp_cb.lcb.data_link_timeout;
  *p_delay_first_pdu_timeout = llcp_cb.lcb.delay_first_pdu_timeout;

  LLCP_TRACE_API4(
      "LLCP_GetConfig () link_miu:%d, opt:0x%02X, wt:%d, link_timeout:%d",
      *p_link_miu, *p_opt, *p_wt, *p_link_timeout);
  LLCP_TRACE_API4(
      "                 inact_timeout (init:%d, target:%d), symm_delay:%d, "
      "data_link_timeout:%d",
      *p_inact_timeout_init, *p_inact_timeout_target, *p_symm_delay,
      *p_data_link_timeout);
  LLCP_TRACE_API1("                 delay_first_pdu_timeout:%d",
                  *p_delay_first_pdu_timeout);
}

/*******************************************************************************
**
** Function         LLCP_GetDiscoveryConfig
**
** Description      Returns discovery config for ISO 18092 MAC link activation
**                  This function is called to get general bytes for
**                  NFC_PMID_ATR_REQ_GEN_BYTES or NFC_PMID_ATR_RES_GEN_BYTES
**                  before starting discovery.
**
**                  wt:Waiting time 0 - 8, only for listen
**                  p_gen_bytes: pointer to store LLCP magic number and
**                               paramters
**                  p_gen_bytes_len: length of buffer for gen bytes as input
**                                   (NOTE:it must be bigger than
**                                   LLCP_MIN_GEN_BYTES) actual gen bytes size
**                                   as output
**
**                  Restrictions on the use of ISO 18092
**                  1. The DID features shall not be used.
**                  2. the NAD features shall not be used.
**                  3. Frame waiting time extentions (WTX) shall not be used.
**
** Returns          None
**
*******************************************************************************/
void LLCP_GetDiscoveryConfig(uint8_t* p_wt, uint8_t* p_gen_bytes,
                             uint8_t* p_gen_bytes_len) {
  uint8_t* p = p_gen_bytes;

  LLCP_TRACE_API0("LLCP_GetDiscoveryConfig ()");

  if (*p_gen_bytes_len < LLCP_MIN_GEN_BYTES) {
    LLCP_TRACE_ERROR1(
        "LLCP_GetDiscoveryConfig (): GenBytes length shall not be smaller than "
        "LLCP_MIN_GEN_BYTES (%d)",
        LLCP_MIN_GEN_BYTES);
    *p_gen_bytes_len = 0;
    return;
  }

  *p_wt = llcp_cb.lcb.local_wt;

  UINT8_TO_BE_STREAM(p, LLCP_MAGIC_NUMBER_BYTE0);
  UINT8_TO_BE_STREAM(p, LLCP_MAGIC_NUMBER_BYTE1);
  UINT8_TO_BE_STREAM(p, LLCP_MAGIC_NUMBER_BYTE2);

#if (LLCP_TEST_INCLUDED == TRUE) /* this is for LLCP testing */
  UINT8_TO_BE_STREAM(p, LLCP_VERSION_TYPE);
  UINT8_TO_BE_STREAM(p, LLCP_VERSION_LEN);
  UINT8_TO_BE_STREAM(p, llcp_test_params.version);

  UINT8_TO_BE_STREAM(p, LLCP_MIUX_TYPE);
  UINT8_TO_BE_STREAM(p, LLCP_MIUX_LEN);
  UINT16_TO_BE_STREAM(p, (llcp_cb.lcb.local_link_miu - LLCP_DEFAULT_MIU));

  UINT8_TO_BE_STREAM(p, LLCP_WKS_TYPE);
  UINT8_TO_BE_STREAM(p, LLCP_WKS_LEN);
  if (llcp_test_params.wks == 0) /* not override */
  {
    UINT16_TO_BE_STREAM(p, llcp_cb.lcb.wks);
  } else {
    UINT16_TO_BE_STREAM(p, llcp_test_params.wks);
  }
#else
  UINT8_TO_BE_STREAM(p, LLCP_VERSION_TYPE);
  UINT8_TO_BE_STREAM(p, LLCP_VERSION_LEN);
  UINT8_TO_BE_STREAM(p, LLCP_VERSION_VALUE);

  UINT8_TO_BE_STREAM(p, LLCP_MIUX_TYPE);
  UINT8_TO_BE_STREAM(p, LLCP_MIUX_LEN);
  UINT16_TO_BE_STREAM(p, (llcp_cb.lcb.local_link_miu - LLCP_DEFAULT_MIU));

  UINT8_TO_BE_STREAM(p, LLCP_WKS_TYPE);
  UINT8_TO_BE_STREAM(p, LLCP_WKS_LEN);
  UINT16_TO_BE_STREAM(p, llcp_cb.lcb.wks);
#endif

  UINT8_TO_BE_STREAM(p, LLCP_LTO_TYPE);
  UINT8_TO_BE_STREAM(p, LLCP_LTO_LEN);
  UINT8_TO_BE_STREAM(p, (llcp_cb.lcb.local_lto / LLCP_LTO_UNIT));

  UINT8_TO_BE_STREAM(p, LLCP_OPT_TYPE);
  UINT8_TO_BE_STREAM(p, LLCP_OPT_LEN);
  UINT8_TO_BE_STREAM(p, llcp_cb.lcb.local_opt);

  *p_gen_bytes_len = (uint8_t)(p - p_gen_bytes);
}

/*******************************************************************************
**
** Function         LLCP_ActivateLink
**
** Description      This function will activate LLCP link with LR, WT and Gen
**                  Bytes in activation NTF from NFCC.
**
**                  LLCP_LINK_ACTIVATION_COMPLETE_EVT will be returned through
**                  callback function if successful.
**                  Otherwise, LLCP_LINK_ACTIVATION_FAILED_EVT will be returned.
**
** Returns          LLCP_STATUS_SUCCESS if success
**
*******************************************************************************/
tLLCP_STATUS LLCP_ActivateLink(tLLCP_ACTIVATE_CONFIG config,
                               tLLCP_LINK_CBACK* p_link_cback) {
  LLCP_TRACE_API1("LLCP_ActivateLink () link_state = %d",
                  llcp_cb.lcb.link_state);

  if ((llcp_cb.lcb.link_state == LLCP_LINK_STATE_DEACTIVATED) &&
      (p_link_cback)) {
    llcp_cb.lcb.p_link_cback = p_link_cback;
    return (llcp_link_activate(&config));
  } else
    return LLCP_STATUS_FAIL;
}

/*******************************************************************************
**
** Function         LLCP_DeactivateLink
**
** Description      Deactivate LLCP link
**
**                  LLCP_LINK_DEACTIVATED_EVT will be returned through callback
**                  when LLCP link is deactivated. Then NFC link may be
**                  deactivated.
**
** Returns          LLCP_STATUS_SUCCESS if success
**
*******************************************************************************/
tLLCP_STATUS LLCP_DeactivateLink(void) {
  LLCP_TRACE_API1("LLCP_DeactivateLink () link_state = %d",
                  llcp_cb.lcb.link_state);

  if (llcp_cb.lcb.link_state != LLCP_LINK_STATE_DEACTIVATED) {
    llcp_link_deactivate(LLCP_LINK_LOCAL_INITIATED);
    return LLCP_STATUS_SUCCESS;
  } else
    return LLCP_STATUS_FAIL;
}

/*******************************************************************************
**
** Function         LLCP_RegisterServer
**
** Description      Register server and callback function
**
**                  reg_sap : Well-Known SAP except LM and SDP (0x02 - 0x0F)
**                            Advertized by SDP (0x10 - 0x1F)
**                            LLCP_INVALID_SAP, LLCP will allocate between 0x10
**                            and 0x1F
**                  link_type : LLCP_LINK_TYPE_LOGICAL_DATA_LINK
**                              and/or LLCP_LINK_TYPE_DATA_LINK_CONNECTION
**                  p_service_name : Null-terminated string up to
**                                   LLCP_MAX_SN_LEN
**
** Returns          SAP between 0x02 and 0x1F, if success
**                  LLCP_INVALID_SAP, otherwise
**
*******************************************************************************/
uint8_t LLCP_RegisterServer(uint8_t reg_sap, uint8_t link_type,
                            char* p_service_name,
                            tLLCP_APP_CBACK* p_app_cback) {
  uint8_t sap;
  uint16_t length;
  tLLCP_APP_CB* p_app_cb = {
      0,
  };

  LLCP_TRACE_API3(
      "LLCP_RegisterServer (): SAP:0x%x, link_type:0x%x, ServiceName:<%s>",
      reg_sap, link_type, ((p_service_name == NULL) ? "" : p_service_name));

  if (!p_app_cback) {
    LLCP_TRACE_ERROR0("LLCP_RegisterServer (): Callback must be provided");
    return LLCP_INVALID_SAP;
  } else if (((link_type & LLCP_LINK_TYPE_LOGICAL_DATA_LINK) == 0x00) &&
             ((link_type & LLCP_LINK_TYPE_DATA_LINK_CONNECTION) == 0x00)) {
    LLCP_TRACE_ERROR1(
        "LLCP_RegisterServer (): link type (0x%x) must be specified",
        link_type);
    return LLCP_INVALID_SAP;
  }

  if (reg_sap == LLCP_INVALID_SAP) {
    /* allocate a SAP between 0x10 and 0x1F */
    for (sap = 0; sap < LLCP_MAX_SERVER; sap++) {
      if (llcp_cb.server_cb[sap].p_app_cback == NULL) {
        p_app_cb = &llcp_cb.server_cb[sap];
        reg_sap = LLCP_LOWER_BOUND_SDP_SAP + sap;
        break;
      }
    }

    if (reg_sap == LLCP_INVALID_SAP) {
      LLCP_TRACE_ERROR0("LLCP_RegisterServer (): out of resource");
      return LLCP_INVALID_SAP;
    }
  } else if (reg_sap == LLCP_SAP_LM) {
    LLCP_TRACE_ERROR1("LLCP_RegisterServer (): SAP (0x%x) is for link manager",
                      reg_sap);
    return LLCP_INVALID_SAP;
  } else if (reg_sap <= LLCP_UPPER_BOUND_WK_SAP) {
    if (reg_sap >= LLCP_MAX_WKS) {
      LLCP_TRACE_ERROR1(
          "LLCP_RegisterServer (): out of resource for SAP (0x%x)", reg_sap);
      return LLCP_INVALID_SAP;
    } else if (llcp_cb.wks_cb[reg_sap].p_app_cback) {
      LLCP_TRACE_ERROR1(
          "LLCP_RegisterServer (): SAP (0x%x) is already registered", reg_sap);
      return LLCP_INVALID_SAP;
    } else {
      p_app_cb = &llcp_cb.wks_cb[reg_sap];
    }
  } else if (reg_sap <= LLCP_UPPER_BOUND_SDP_SAP) {
    if (reg_sap - LLCP_LOWER_BOUND_SDP_SAP >= LLCP_MAX_SERVER) {
      LLCP_TRACE_ERROR1(
          "LLCP_RegisterServer (): out of resource for SAP (0x%x)", reg_sap);
      return LLCP_INVALID_SAP;
    } else if (llcp_cb.server_cb[reg_sap - LLCP_LOWER_BOUND_SDP_SAP]
                   .p_app_cback) {
      LLCP_TRACE_ERROR1(
          "LLCP_RegisterServer (): SAP (0x%x) is already registered", reg_sap);
      return LLCP_INVALID_SAP;
    } else {
      p_app_cb = &llcp_cb.server_cb[reg_sap - LLCP_LOWER_BOUND_SDP_SAP];
    }
  } else if (reg_sap >= LLCP_LOWER_BOUND_LOCAL_SAP) {
    LLCP_TRACE_ERROR2(
        "LLCP_RegisterServer (): SAP (0x%x) must be less than 0x%x", reg_sap,
        LLCP_LOWER_BOUND_LOCAL_SAP);
    return LLCP_INVALID_SAP;
  }

  memset(p_app_cb, 0x00, sizeof(tLLCP_APP_CB));

  if (p_service_name) {
    length = (uint8_t)strlen(p_service_name);
    if (length > LLCP_MAX_SN_LEN) {
      LLCP_TRACE_ERROR1(
          "LLCP_RegisterServer (): Service Name (%d bytes) is too long",
          length);
      return LLCP_INVALID_SAP;
    }

    p_app_cb->p_service_name = (uint8_t*)GKI_getbuf((uint16_t)(length + 1));
    if (p_app_cb->p_service_name == NULL) {
      LLCP_TRACE_ERROR0("LLCP_RegisterServer (): Out of resource");
      return LLCP_INVALID_SAP;
    }

    strncpy((char*)p_app_cb->p_service_name, (char*)p_service_name, length + 1);
    p_app_cb->p_service_name[length] = 0;
  } else
    p_app_cb->p_service_name = NULL;

  p_app_cb->p_app_cback = p_app_cback;
  p_app_cb->link_type = link_type;

  if (reg_sap <= LLCP_UPPER_BOUND_WK_SAP) {
    llcp_cb.lcb.wks |= (1 << reg_sap);
  }

  LLCP_TRACE_DEBUG1("LLCP_RegisterServer (): Registered SAP = 0x%02X", reg_sap);

  if (link_type & LLCP_LINK_TYPE_LOGICAL_DATA_LINK) {
    llcp_cb.num_logical_data_link++;
    llcp_util_adjust_ll_congestion();
  }

  return reg_sap;
}

/*******************************************************************************
**
** Function         LLCP_RegisterClient
**
** Description      Register client and callback function
**
**                  link_type : LLCP_LINK_TYPE_LOGICAL_DATA_LINK
**                              and/or LLCP_LINK_TYPE_DATA_LINK_CONNECTION
**
** Returns          SAP between 0x20 and 0x3F, if success
**                  LLCP_INVALID_SAP, otherwise
**
*******************************************************************************/
uint8_t LLCP_RegisterClient(uint8_t link_type, tLLCP_APP_CBACK* p_app_cback) {
  uint8_t reg_sap = LLCP_INVALID_SAP;
  uint8_t sap;
  tLLCP_APP_CB* p_app_cb;

  LLCP_TRACE_API1("LLCP_RegisterClient (): link_type = 0x%x", link_type);

  if (!p_app_cback) {
    LLCP_TRACE_ERROR0("LLCP_RegisterClient (): Callback must be provided");
    return LLCP_INVALID_SAP;
  } else if (((link_type & LLCP_LINK_TYPE_LOGICAL_DATA_LINK) == 0x00) &&
             ((link_type & LLCP_LINK_TYPE_DATA_LINK_CONNECTION) == 0x00)) {
    LLCP_TRACE_ERROR1(
        "LLCP_RegisterClient (): link type (0x%x) must be specified",
        link_type);
    return LLCP_INVALID_SAP;
  }

  /* allocate a SAP between 0x20 and 0x3F */
  for (sap = 0; sap < LLCP_MAX_CLIENT; sap++) {
    if (llcp_cb.client_cb[sap].p_app_cback == NULL) {
      p_app_cb = &llcp_cb.client_cb[sap];
      memset(p_app_cb, 0x00, sizeof(tLLCP_APP_CB));
      reg_sap = LLCP_LOWER_BOUND_LOCAL_SAP + sap;
      break;
    }
  }

  if (reg_sap == LLCP_INVALID_SAP) {
    LLCP_TRACE_ERROR0("LLCP_RegisterClient (): out of resource");
    return LLCP_INVALID_SAP;
  }

  p_app_cb->p_app_cback = p_app_cback;
  p_app_cb->p_service_name = NULL;
  p_app_cb->link_type = link_type;

  LLCP_TRACE_DEBUG1("LLCP_RegisterClient (): Registered SAP = 0x%02X", reg_sap);

  if (link_type & LLCP_LINK_TYPE_LOGICAL_DATA_LINK) {
    llcp_cb.num_logical_data_link++;
    llcp_util_adjust_ll_congestion();
  }

  return reg_sap;
}

/*******************************************************************************
**
** Function         LLCP_Deregister
**
** Description      Deregister server or client
**
**
** Returns          LLCP_STATUS_SUCCESS if success
**
*******************************************************************************/
tLLCP_STATUS LLCP_Deregister(uint8_t local_sap) {
  uint8_t idx;
  tLLCP_APP_CB* p_app_cb;

  LLCP_TRACE_API1("LLCP_Deregister () SAP:0x%x", local_sap);

  p_app_cb = llcp_util_get_app_cb(local_sap);

  if ((!p_app_cb) || (p_app_cb->p_app_cback == NULL)) {
    LLCP_TRACE_ERROR1("LLCP_Deregister (): SAP (0x%x) is not registered",
                      local_sap);
    return LLCP_STATUS_FAIL;
  }

  if (p_app_cb->p_service_name) GKI_freebuf(p_app_cb->p_service_name);

  /* update WKS bit map */
  if (local_sap <= LLCP_UPPER_BOUND_WK_SAP) {
    llcp_cb.lcb.wks &= ~(1 << local_sap);
  }

  /* discard any received UI PDU on this SAP */
  LLCP_FlushLogicalLinkRxData(local_sap);
  llcp_cb.total_rx_ui_pdu = 0;

  /* deallocate any data link connection on this SAP */
  for (idx = 0; idx < LLCP_MAX_DATA_LINK; idx++) {
    if ((llcp_cb.dlcb[idx].state != LLCP_DLC_STATE_IDLE) &&
        (llcp_cb.dlcb[idx].local_sap == local_sap)) {
      llcp_util_deallocate_data_link(&llcp_cb.dlcb[idx]);
    }
  }

  p_app_cb->p_app_cback = NULL;

  /* discard any pending tx UI PDU from this SAP */
  while (p_app_cb->ui_xmit_q.p_first) {
    GKI_freebuf(GKI_dequeue(&p_app_cb->ui_xmit_q));
    llcp_cb.total_tx_ui_pdu--;
  }

  if (p_app_cb->link_type & LLCP_LINK_TYPE_LOGICAL_DATA_LINK) {
    llcp_cb.num_logical_data_link--;
    llcp_util_adjust_ll_congestion();
  }

  /* check rx congestion status */
  llcp_util_check_rx_congested_status();

  return LLCP_STATUS_SUCCESS;
}

/*******************************************************************************
**
** Function         LLCP_IsLogicalLinkCongested
**
** Description      Check if logical link is congested
**
**
** Returns          TRUE if congested
**
*******************************************************************************/
bool LLCP_IsLogicalLinkCongested(uint8_t local_sap, uint8_t num_pending_ui_pdu,
                                 uint8_t total_pending_ui_pdu,
                                 uint8_t total_pending_i_pdu) {
  tLLCP_APP_CB* p_app_cb;

  LLCP_TRACE_API4(
      "LLCP_IsLogicalLinkCongested () Local SAP:0x%x, pending = (%d, %d, %d)",
      local_sap, num_pending_ui_pdu, total_pending_ui_pdu, total_pending_i_pdu);

  p_app_cb = llcp_util_get_app_cb(local_sap);

  if ((llcp_cb.lcb.link_state != LLCP_LINK_STATE_ACTIVATED) ||
      (p_app_cb == NULL) || (p_app_cb->p_app_cback == NULL) ||
      ((p_app_cb->link_type & LLCP_LINK_TYPE_LOGICAL_DATA_LINK) == 0) ||
      (p_app_cb->is_ui_tx_congested)) {
    return true;
  } else if ((num_pending_ui_pdu + p_app_cb->ui_xmit_q.count >=
              llcp_cb.ll_tx_congest_start) ||
             (total_pending_ui_pdu + llcp_cb.total_tx_ui_pdu >=
              llcp_cb.max_num_ll_tx_buff) ||
             (total_pending_ui_pdu + total_pending_i_pdu +
                  llcp_cb.total_tx_ui_pdu + llcp_cb.total_tx_i_pdu >=
              llcp_cb.max_num_tx_buff)) {
    /* set flag so LLCP can notify uncongested status later */
    p_app_cb->is_ui_tx_congested = true;

    return true;
  }
  return false;
}

/*******************************************************************************
**
** Function         LLCP_SendUI
**
** Description      Send connnectionless data to DSAP
**
**
** Returns          LLCP_STATUS_SUCCESS if success
**                  LLCP_STATUS_CONGESTED if logical link is congested
**                  LLCP_STATUS_FAIL, otherwise
**
*******************************************************************************/
tLLCP_STATUS LLCP_SendUI(uint8_t ssap, uint8_t dsap, NFC_HDR* p_buf) {
  tLLCP_STATUS status = LLCP_STATUS_FAIL;
  tLLCP_APP_CB* p_app_cb;

  LLCP_TRACE_API2("LLCP_SendUI () SSAP=0x%x, DSAP=0x%x", ssap, dsap);

  p_app_cb = llcp_util_get_app_cb(ssap);

  if ((p_app_cb == NULL) || (p_app_cb->p_app_cback == NULL)) {
    LLCP_TRACE_ERROR1("LLCP_SendUI (): SSAP (0x%x) is not registered", ssap);
  } else if ((p_app_cb->link_type & LLCP_LINK_TYPE_LOGICAL_DATA_LINK) == 0) {
    LLCP_TRACE_ERROR1(
        "LLCP_SendUI (): Logical link on SSAP (0x%x) is not enabled", ssap);
  } else if (llcp_cb.lcb.link_state != LLCP_LINK_STATE_ACTIVATED) {
    LLCP_TRACE_ERROR0("LLCP_SendUI (): LLCP link is not activated");
  } else if ((llcp_cb.lcb.peer_opt == LLCP_LSC_UNKNOWN) ||
             (llcp_cb.lcb.peer_opt & LLCP_LSC_1)) {
    if (p_buf->len <= llcp_cb.lcb.peer_miu) {
      if (p_buf->offset >= LLCP_MIN_OFFSET) {
        status = llcp_util_send_ui(ssap, dsap, p_app_cb, p_buf);
      } else {
        LLCP_TRACE_ERROR2("LLCP_SendUI (): offset (%d) must be %d at least",
                          p_buf->offset, LLCP_MIN_OFFSET);
      }
    } else {
      LLCP_TRACE_ERROR0(
          "LLCP_SendUI (): Data length shall not be bigger than peer's link "
          "MIU");
    }
  } else {
    LLCP_TRACE_ERROR0(
        "LLCP_SendUI (): Peer doesn't support connectionless link");
  }

  if (status == LLCP_STATUS_FAIL) {
    GKI_freebuf(p_buf);
  }

  return status;
}

/*******************************************************************************
**
** Function         LLCP_ReadLogicalLinkData
**
** Description      Read information of UI PDU for local SAP
**
**                  - Remote SAP who sent UI PDU is returned.
**                  - Information of UI PDU up to max_data_len is copied into
**                    p_data.
**                  - Information of next UI PDU is not concatenated.
**                  - Recommended max_data_len is link MIU of local device
**
** Returns          TRUE if more information of UI PDU or more UI PDU in queue
**
*******************************************************************************/
bool LLCP_ReadLogicalLinkData(uint8_t local_sap, uint32_t max_data_len,
                              uint8_t* p_remote_sap, uint32_t* p_data_len,
                              uint8_t* p_data) {
  tLLCP_APP_CB* p_app_cb;
  NFC_HDR* p_buf;
  uint8_t* p_ui_pdu;
  uint16_t pdu_hdr, ui_pdu_length;

  LLCP_TRACE_API1("LLCP_ReadLogicalLinkData () Local SAP:0x%x", local_sap);

  *p_data_len = 0;

  p_app_cb = llcp_util_get_app_cb(local_sap);

  /* if application is registered */
  if ((p_app_cb) && (p_app_cb->p_app_cback)) {
    /* if any UI PDU in rx queue */
    if (p_app_cb->ui_rx_q.p_first) {
      p_buf = (NFC_HDR*)p_app_cb->ui_rx_q.p_first;
      p_ui_pdu = (uint8_t*)(p_buf + 1) + p_buf->offset;

      /* get length of UI PDU */
      BE_STREAM_TO_UINT16(ui_pdu_length, p_ui_pdu);

      /* get remote SAP from LLCP header */
      BE_STREAM_TO_UINT16(pdu_hdr, p_ui_pdu);
      *p_remote_sap = LLCP_GET_SSAP(pdu_hdr);

      /* layer_specific has the offset to read within UI PDU */
      p_ui_pdu += p_buf->layer_specific;

      /* copy data up to max_data_len */
      if (max_data_len >= (uint32_t)(ui_pdu_length - LLCP_PDU_HEADER_SIZE -
                                     p_buf->layer_specific)) {
        /* copy information without LLCP header */
        *p_data_len = (uint32_t)(ui_pdu_length - LLCP_PDU_HEADER_SIZE -
                                 p_buf->layer_specific);

        /* move to next UI PDU if any */
        p_buf->layer_specific =
            0; /* reset offset to read from the first byte of next UI PDU */
        p_buf->offset += LLCP_PDU_AGF_LEN_SIZE + ui_pdu_length;
        p_buf->len -= LLCP_PDU_AGF_LEN_SIZE + ui_pdu_length;
      } else {
        *p_data_len = max_data_len;

        /* update offset to read from remaining UI PDU next time */
        p_buf->layer_specific += max_data_len;
      }

      memcpy(p_data, p_ui_pdu, *p_data_len);

      /* if read all of UI PDU */
      if (p_buf->len == 0) {
        GKI_dequeue(&p_app_cb->ui_rx_q);
        GKI_freebuf(p_buf);

        /* decrease number of received UI PDU in in all of ui_rx_q and check rx
         * congestion status */
        llcp_cb.total_rx_ui_pdu--;
        llcp_util_check_rx_congested_status();
      }
    }

    /* if there is more UI PDU in rx queue */
    if (p_app_cb->ui_rx_q.p_first) {
      return true;
    } else {
      return false;
    }
  } else {
    LLCP_TRACE_ERROR1("LLCP_ReadLogicalLinkData (): Unregistered SAP:0x%x",
                      local_sap);

    return false;
  }
}

/*******************************************************************************
**
** Function         LLCP_FlushLogicalLinkRxData
**
** Description      Discard received data in logical data link of local SAP
**
**
** Returns          length of data flushed
**
*******************************************************************************/
uint32_t LLCP_FlushLogicalLinkRxData(uint8_t local_sap) {
  NFC_HDR* p_buf;
  uint32_t flushed_length = 0;
  tLLCP_APP_CB* p_app_cb;
  uint8_t* p_ui_pdu;
  uint16_t ui_pdu_length;

  LLCP_TRACE_API1("LLCP_FlushLogicalLinkRxData () Local SAP:0x%x", local_sap);

  p_app_cb = llcp_util_get_app_cb(local_sap);

  /* if application is registered */
  if ((p_app_cb) && (p_app_cb->p_app_cback)) {
    /* if any UI PDU in rx queue */
    while (p_app_cb->ui_rx_q.p_first) {
      p_buf = (NFC_HDR*)p_app_cb->ui_rx_q.p_first;
      p_ui_pdu = (uint8_t*)(p_buf + 1) + p_buf->offset;

      /* get length of UI PDU */
      BE_STREAM_TO_UINT16(ui_pdu_length, p_ui_pdu);

      flushed_length += (uint32_t)(ui_pdu_length - LLCP_PDU_HEADER_SIZE -
                                   p_buf->layer_specific);

      /* move to next UI PDU if any */
      p_buf->layer_specific = 0; /* offset */
      p_buf->offset += LLCP_PDU_AGF_LEN_SIZE + ui_pdu_length;
      p_buf->len -= LLCP_PDU_AGF_LEN_SIZE + ui_pdu_length;

      /* if read all of UI PDU */
      if (p_buf->len == 0) {
        GKI_dequeue(&p_app_cb->ui_rx_q);
        GKI_freebuf(p_buf);
        llcp_cb.total_rx_ui_pdu--;
      }
    }

    /* number of received UI PDU is decreased so check rx congestion status */
    llcp_util_check_rx_congested_status();
  } else {
    LLCP_TRACE_ERROR1("LLCP_FlushLogicalLinkRxData (): Unregistered SAP:0x%x",
                      local_sap);
  }

  return (flushed_length);
}

/*******************************************************************************
**
** Function         LLCP_ConnectReq
**
** Description      Create data link connection between registered SAP and DSAP
**                  in peer LLCP,
**
**
** Returns          LLCP_STATUS_SUCCESS if success
**                  LLCP_STATUS_FAIL, otherwise
**
*******************************************************************************/
tLLCP_STATUS LLCP_ConnectReq(uint8_t reg_sap, uint8_t dsap,
                             tLLCP_CONNECTION_PARAMS* p_params) {
  tLLCP_DLCB* p_dlcb;
  tLLCP_STATUS status;
  tLLCP_APP_CB* p_app_cb;
  tLLCP_CONNECTION_PARAMS params;

  LLCP_TRACE_API2("LLCP_ConnectReq () reg_sap=0x%x, DSAP=0x%x", reg_sap, dsap);

  if ((llcp_cb.lcb.peer_opt != LLCP_LSC_UNKNOWN) &&
      ((llcp_cb.lcb.peer_opt & LLCP_LSC_2) == 0)) {
    LLCP_TRACE_ERROR0(
        "LLCP_ConnectReq (): Peer doesn't support connection-oriented link");
    return LLCP_STATUS_FAIL;
  }

  if (!p_params) {
    params.miu = LLCP_DEFAULT_MIU;
    params.rw = LLCP_DEFAULT_RW;
    params.sn[0] = 0;
    p_params = &params;
  }

  p_app_cb = llcp_util_get_app_cb(reg_sap);

  /* if application is registered */
  if ((p_app_cb == NULL) || (p_app_cb->p_app_cback == NULL)) {
    LLCP_TRACE_ERROR1("LLCP_ConnectReq (): SSAP (0x%x) is not registered",
                      reg_sap);
    return LLCP_STATUS_FAIL;
  }

  if (dsap == LLCP_SAP_LM) {
    LLCP_TRACE_ERROR1(
        "LLCP_ConnectReq (): DSAP (0x%x) must not be link manager SAP", dsap);
    return LLCP_STATUS_FAIL;
  }

  if (dsap == LLCP_SAP_SDP) {
    if (strlen(p_params->sn) > LLCP_MAX_SN_LEN) {
      LLCP_TRACE_ERROR1(
          "LLCP_ConnectReq (): Service Name (%d bytes) is too long",
          strlen(p_params->sn));
      return LLCP_STATUS_FAIL;
    }
  }

  if ((p_params) && (p_params->miu > llcp_cb.lcb.local_link_miu)) {
    LLCP_TRACE_ERROR0(
        "LLCP_ConnectReq (): Data link MIU shall not be bigger than local link "
        "MIU");
    return LLCP_STATUS_FAIL;
  }

  /* check if any pending connection request on this reg_sap */
  p_dlcb = llcp_dlc_find_dlcb_by_sap(reg_sap, LLCP_INVALID_SAP);
  if (p_dlcb) {
    /*
    ** Accepting LLCP may change SAP in CC, so we cannot find right data
    ** link connection if there is multiple pending connection request on
    ** the same local SAP.
    */
    LLCP_TRACE_ERROR0(
        "LLCP_ConnectReq (): There is pending connect request on this reg_sap");
    return LLCP_STATUS_FAIL;
  }

  p_dlcb = llcp_util_allocate_data_link(reg_sap, dsap);

  if (p_dlcb) {
    status =
        llcp_dlsm_execute(p_dlcb, LLCP_DLC_EVENT_API_CONNECT_REQ, p_params);
    if (status != LLCP_STATUS_SUCCESS) {
      LLCP_TRACE_ERROR0("LLCP_ConnectReq (): Error in state machine");
      llcp_util_deallocate_data_link(p_dlcb);
      return LLCP_STATUS_FAIL;
    }
  } else {
    return LLCP_STATUS_FAIL;
  }

  return LLCP_STATUS_SUCCESS;
}

/*******************************************************************************
**
** Function         LLCP_ConnectCfm
**
** Description      Accept connection request from peer LLCP
**
**
** Returns          LLCP_STATUS_SUCCESS if success
**                  LLCP_STATUS_FAIL, otherwise
**
*******************************************************************************/
tLLCP_STATUS LLCP_ConnectCfm(uint8_t local_sap, uint8_t remote_sap,
                             tLLCP_CONNECTION_PARAMS* p_params) {
  tLLCP_STATUS status;
  tLLCP_DLCB* p_dlcb;
  tLLCP_CONNECTION_PARAMS params;

  LLCP_TRACE_API2("LLCP_ConnectCfm () Local SAP:0x%x, Remote SAP:0x%x)",
                  local_sap, remote_sap);

  if (!p_params) {
    params.miu = LLCP_DEFAULT_MIU;
    params.rw = LLCP_DEFAULT_RW;
    params.sn[0] = 0;
    p_params = &params;
  }
  if (p_params->miu > llcp_cb.lcb.local_link_miu) {
    LLCP_TRACE_ERROR0(
        "LLCP_ConnectCfm (): Data link MIU shall not be bigger than local link "
        "MIU");
    return LLCP_STATUS_FAIL;
  }

  p_dlcb = llcp_dlc_find_dlcb_by_sap(local_sap, remote_sap);

  if (p_dlcb) {
    status =
        llcp_dlsm_execute(p_dlcb, LLCP_DLC_EVENT_API_CONNECT_CFM, p_params);
  } else {
    LLCP_TRACE_ERROR0("LLCP_ConnectCfm (): No data link");
    status = LLCP_STATUS_FAIL;
  }

  return status;
}

/*******************************************************************************
**
** Function         LLCP_ConnectReject
**
** Description      Reject connection request from peer LLCP
**
**                  reason : LLCP_SAP_DM_REASON_APP_REJECTED
**                           LLCP_SAP_DM_REASON_PERM_REJECT_THIS
**                           LLCP_SAP_DM_REASON_PERM_REJECT_ANY
**                           LLCP_SAP_DM_REASON_TEMP_REJECT_THIS
**                           LLCP_SAP_DM_REASON_TEMP_REJECT_ANY
**
** Returns          LLCP_STATUS_SUCCESS if success
**                  LLCP_STATUS_FAIL, otherwise
**
*******************************************************************************/
tLLCP_STATUS LLCP_ConnectReject(uint8_t local_sap, uint8_t remote_sap,
                                uint8_t reason) {
  tLLCP_STATUS status;
  tLLCP_DLCB* p_dlcb;

  LLCP_TRACE_API3(
      "LLCP_ConnectReject () Local SAP:0x%x, Remote SAP:0x%x, reason:0x%x",
      local_sap, remote_sap, reason);

  p_dlcb = llcp_dlc_find_dlcb_by_sap(local_sap, remote_sap);

  if (p_dlcb) {
    status =
        llcp_dlsm_execute(p_dlcb, LLCP_DLC_EVENT_API_CONNECT_REJECT, &reason);
    llcp_util_deallocate_data_link(p_dlcb);
  } else {
    LLCP_TRACE_ERROR0("LLCP_ConnectReject (): No data link");
    status = LLCP_STATUS_FAIL;
  }

  return status;
}

/*******************************************************************************
**
** Function         LLCP_IsDataLinkCongested
**
** Description      Check if data link connection is congested
**
**
** Returns          TRUE if congested
**
*******************************************************************************/
bool LLCP_IsDataLinkCongested(uint8_t local_sap, uint8_t remote_sap,
                              uint8_t num_pending_i_pdu,
                              uint8_t total_pending_ui_pdu,
                              uint8_t total_pending_i_pdu) {
  tLLCP_DLCB* p_dlcb;

  LLCP_TRACE_API5(
      "LLCP_IsDataLinkCongested () Local SAP:0x%x, Remote SAP:0x%x, pending = "
      "(%d, %d, %d)",
      local_sap, remote_sap, num_pending_i_pdu, total_pending_ui_pdu,
      total_pending_i_pdu);

  p_dlcb = llcp_dlc_find_dlcb_by_sap(local_sap, remote_sap);

  if (p_dlcb) {
    if ((p_dlcb->is_tx_congested) || (p_dlcb->remote_busy)) {
      return true;
    } else if ((num_pending_i_pdu + p_dlcb->i_xmit_q.count >=
                p_dlcb->remote_rw) ||
               (total_pending_ui_pdu + total_pending_i_pdu +
                    llcp_cb.total_tx_ui_pdu + llcp_cb.total_tx_i_pdu >=
                llcp_cb.max_num_tx_buff)) {
      /* set flag so LLCP can notify uncongested status later */
      p_dlcb->is_tx_congested = true;
      return true;
    }
    return false;
  }
  return true;
}

/*******************************************************************************
**
** Function         LLCP_SendData
**
** Description      Send connection-oriented data
**
**
** Returns          LLCP_STATUS_SUCCESS if success
**                  LLCP_STATUS_CONGESTED if data link is congested
**
*******************************************************************************/
tLLCP_STATUS LLCP_SendData(uint8_t local_sap, uint8_t remote_sap,
                           NFC_HDR* p_buf) {
  tLLCP_STATUS status = LLCP_STATUS_FAIL;
  tLLCP_DLCB* p_dlcb;

  LLCP_TRACE_API2("LLCP_SendData () Local SAP:0x%x, Remote SAP:0x%x", local_sap,
                  remote_sap);

  p_dlcb = llcp_dlc_find_dlcb_by_sap(local_sap, remote_sap);

  if (p_dlcb) {
    if (p_dlcb->remote_miu >= p_buf->len) {
      if (p_buf->offset >= LLCP_MIN_OFFSET) {
        status = llcp_dlsm_execute(p_dlcb, LLCP_DLC_EVENT_API_DATA_REQ, p_buf);
      } else {
        LLCP_TRACE_ERROR2("LLCP_SendData (): offset (%d) must be %d at least",
                          p_buf->offset, LLCP_MIN_OFFSET);
      }
    } else {
      LLCP_TRACE_ERROR2(
          "LLCP_SendData (): Information (%d bytes) cannot be more than peer "
          "MIU (%d bytes)",
          p_buf->len, p_dlcb->remote_miu);
    }
  } else {
    LLCP_TRACE_ERROR0("LLCP_SendData (): No data link");
  }

  if (status == LLCP_STATUS_FAIL) {
    GKI_freebuf(p_buf);
  }

  return status;
}

/*******************************************************************************
**
** Function         LLCP_ReadDataLinkData
**
** Description      Read information of I PDU for data link connection
**
**                  - Information of I PDU up to max_data_len is copied into
**                    p_data.
**                  - Information of next I PDU is not concatenated.
**                  - Recommended max_data_len is data link connection MIU of
**                    local end point
**
** Returns          TRUE if more data in queue
**
*******************************************************************************/
bool LLCP_ReadDataLinkData(uint8_t local_sap, uint8_t remote_sap,
                           uint32_t max_data_len, uint32_t* p_data_len,
                           uint8_t* p_data) {
  tLLCP_DLCB* p_dlcb;
  NFC_HDR* p_buf;
  uint8_t* p_i_pdu;
  uint16_t i_pdu_length;

  LLCP_TRACE_API2("LLCP_ReadDataLinkData () Local SAP:0x%x, Remote SAP:0x%x",
                  local_sap, remote_sap);

  p_dlcb = llcp_dlc_find_dlcb_by_sap(local_sap, remote_sap);

  *p_data_len = 0;
  if (p_dlcb) {
    /* if any I PDU in rx queue */
    if (p_dlcb->i_rx_q.p_first) {
      p_buf = (NFC_HDR*)p_dlcb->i_rx_q.p_first;
      p_i_pdu = (uint8_t*)(p_buf + 1) + p_buf->offset;

      /* get length of I PDU */
      BE_STREAM_TO_UINT16(i_pdu_length, p_i_pdu);

      /* layer_specific has the offset to read within I PDU */
      p_i_pdu += p_buf->layer_specific;

      /* copy data up to max_data_len */
      if (max_data_len >= (uint32_t)(i_pdu_length - p_buf->layer_specific)) {
        /* copy information */
        *p_data_len = (uint32_t)(i_pdu_length - p_buf->layer_specific);

        /* move to next I PDU if any */
        p_buf->layer_specific =
            0; /* reset offset to read from the first byte of next I PDU */
        p_buf->offset += LLCP_PDU_AGF_LEN_SIZE + i_pdu_length;
        p_buf->len -= LLCP_PDU_AGF_LEN_SIZE + i_pdu_length;
      } else {
        *p_data_len = max_data_len;

        /* update offset to read from remaining I PDU next time */
        p_buf->layer_specific += max_data_len;
      }

      memcpy(p_data, p_i_pdu, *p_data_len);

      if (p_buf->layer_specific == 0) {
        p_dlcb->num_rx_i_pdu--;
      }

      /* if read all of I PDU */
      if (p_buf->len == 0) {
        GKI_dequeue(&p_dlcb->i_rx_q);
        GKI_freebuf(p_buf);

        /* decrease number of received I PDU in in all of ui_rx_q and check rx
         * congestion status */
        llcp_cb.total_rx_i_pdu--;
        llcp_util_check_rx_congested_status();
      }
    }

    /* if getting out of rx congestion */
    if ((!p_dlcb->local_busy) && (p_dlcb->is_rx_congested) &&
        (p_dlcb->num_rx_i_pdu <= p_dlcb->rx_congest_threshold / 2)) {
      /* send RR */
      p_dlcb->is_rx_congested = false;
      p_dlcb->flags |= LLCP_DATA_LINK_FLAG_PENDING_RR_RNR;
    }

    /* if there is more I PDU in rx queue */
    if (p_dlcb->i_rx_q.p_first) {
      return true;
    } else {
      return false;
    }
  } else {
    LLCP_TRACE_ERROR0("LLCP_ReadDataLinkData (): No data link connection");

    return false;
  }
}

/*******************************************************************************
**
** Function         LLCP_FlushDataLinkRxData
**
** Description      Discard received data in data link connection
**
**
** Returns          length of rx data flushed
**
*******************************************************************************/
uint32_t LLCP_FlushDataLinkRxData(uint8_t local_sap, uint8_t remote_sap) {
  tLLCP_DLCB* p_dlcb;
  NFC_HDR* p_buf;
  uint32_t flushed_length = 0;
  uint8_t* p_i_pdu;
  uint16_t i_pdu_length;

  LLCP_TRACE_API2("LLCP_FlushDataLinkRxData () Local SAP:0x%x, Remote SAP:0x%x",
                  local_sap, remote_sap);

  p_dlcb = llcp_dlc_find_dlcb_by_sap(local_sap, remote_sap);

  if (p_dlcb) {
    /* if any I PDU in rx queue */
    while (p_dlcb->i_rx_q.p_first) {
      p_buf = (NFC_HDR*)p_dlcb->i_rx_q.p_first;
      p_i_pdu = (uint8_t*)(p_buf + 1) + p_buf->offset;

      /* get length of I PDU */
      BE_STREAM_TO_UINT16(i_pdu_length, p_i_pdu);

      flushed_length += (uint32_t)(i_pdu_length - p_buf->layer_specific);

      /* move to next I PDU if any */
      p_buf->layer_specific = 0; /* offset */
      p_buf->offset += LLCP_PDU_AGF_LEN_SIZE + i_pdu_length;
      p_buf->len -= LLCP_PDU_AGF_LEN_SIZE + i_pdu_length;

      /* if read all of I PDU */
      if (p_buf->len == 0) {
        GKI_dequeue(&p_dlcb->i_rx_q);
        GKI_freebuf(p_buf);
        llcp_cb.total_rx_i_pdu--;
      }
    }

    p_dlcb->num_rx_i_pdu = 0;

    /* if getting out of rx congestion */
    if ((!p_dlcb->local_busy) && (p_dlcb->is_rx_congested)) {
      /* send RR */
      p_dlcb->is_rx_congested = false;
      p_dlcb->flags |= LLCP_DATA_LINK_FLAG_PENDING_RR_RNR;
    }

    /* number of received I PDU is decreased so check rx congestion status */
    llcp_util_check_rx_congested_status();
  } else {
    LLCP_TRACE_ERROR0("LLCP_FlushDataLinkRxData (): No data link connection");
  }

  return (flushed_length);
}

/*******************************************************************************
**
** Function         LLCP_DisconnectReq
**
** Description      Disconnect data link
**                  discard any pending data if flush is set to TRUE
**
** Returns          LLCP_STATUS_SUCCESS if success
**
*******************************************************************************/
tLLCP_STATUS LLCP_DisconnectReq(uint8_t local_sap, uint8_t remote_sap,
                                bool flush) {
  tLLCP_STATUS status;
  tLLCP_DLCB* p_dlcb;

  LLCP_TRACE_API3(
      "LLCP_DisconnectReq () Local SAP:0x%x, Remote SAP:0x%x, flush=%d",
      local_sap, remote_sap, flush);

  p_dlcb = llcp_dlc_find_dlcb_by_sap(local_sap, remote_sap);

  if (p_dlcb) {
    status =
        llcp_dlsm_execute(p_dlcb, LLCP_DLC_EVENT_API_DISCONNECT_REQ, &flush);
  } else {
    LLCP_TRACE_ERROR0("LLCP_DisconnectReq (): No data link");
    status = LLCP_STATUS_FAIL;
  }

  return status;
}

/*******************************************************************************
**
** Function         LLCP_SetTxCompleteNtf
**
** Description      This function is called to get LLCP_SERVICE_TX_COMPLETE
**                  when Tx queue is empty and all PDU is acked.
**                  This is one time event, so upper layer shall call this
**                  function again to get next LLCP_SERVICE_TX_COMPLETE.
**
** Returns          LLCP_STATUS_SUCCESS if success
**
*******************************************************************************/
tLLCP_STATUS LLCP_SetTxCompleteNtf(uint8_t local_sap, uint8_t remote_sap) {
  tLLCP_STATUS status;
  tLLCP_DLCB* p_dlcb;

  LLCP_TRACE_API2("LLCP_SetTxCompleteNtf () Local SAP:0x%x, Remote SAP:0x%x",
                  local_sap, remote_sap);

  p_dlcb = llcp_dlc_find_dlcb_by_sap(local_sap, remote_sap);

  if (p_dlcb) {
    /* set flag to notify upper later when tx complete */
    p_dlcb->flags |= LLCP_DATA_LINK_FLAG_NOTIFY_TX_DONE;
    status = LLCP_STATUS_SUCCESS;
  } else {
    LLCP_TRACE_ERROR0("LLCP_SetTxCompleteNtf (): No data link");
    status = LLCP_STATUS_FAIL;
  }

  return status;
}

/*******************************************************************************
**
** Function         LLCP_SetLocalBusyStatus
**
** Description      Set local busy status
**
**
** Returns          LLCP_STATUS_SUCCESS if success
**
*******************************************************************************/
tLLCP_STATUS LLCP_SetLocalBusyStatus(uint8_t local_sap, uint8_t remote_sap,
                                     bool is_busy) {
  tLLCP_STATUS status;
  tLLCP_DLCB* p_dlcb;

  LLCP_TRACE_API2("LLCP_SetLocalBusyStatus () Local SAP:0x%x, is_busy=%d",
                  local_sap, is_busy);

  p_dlcb = llcp_dlc_find_dlcb_by_sap(local_sap, remote_sap);

  if (p_dlcb) {
    if (p_dlcb->local_busy != is_busy) {
      p_dlcb->local_busy = is_busy;

      /* send RR or RNR with valid sequence */
      p_dlcb->flags |= LLCP_DATA_LINK_FLAG_PENDING_RR_RNR;

      if (is_busy == false) {
        if (p_dlcb->i_rx_q.count) {
          llcp_dlsm_execute(p_dlcb, LLCP_DLC_EVENT_PEER_DATA_IND, NULL);
        }
      }
    }
    status = LLCP_STATUS_SUCCESS;
  } else {
    LLCP_TRACE_ERROR0("LLCP_SetLocalBusyStatus (): No data link");
    status = LLCP_STATUS_FAIL;
  }

  return status;
}

/*******************************************************************************
**
** Function         LLCP_GetRemoteWKS
**
** Description      Return well-known service bitmap of connected device
**
**
** Returns          WKS bitmap if success
**
*******************************************************************************/
uint16_t LLCP_GetRemoteWKS(void) {
  LLCP_TRACE_API1("LLCP_GetRemoteWKS () WKS:0x%04x",
                  (llcp_cb.lcb.link_state == LLCP_LINK_STATE_ACTIVATED)
                      ? llcp_cb.lcb.peer_wks
                      : 0);

  if (llcp_cb.lcb.link_state == LLCP_LINK_STATE_ACTIVATED)
    return (llcp_cb.lcb.peer_wks);
  else
    return (0);
}

/*******************************************************************************
**
** Function         LLCP_GetRemoteLSC
**
** Description      Return link service class of connected device
**
**
** Returns          link service class
**
*******************************************************************************/
uint8_t LLCP_GetRemoteLSC(void) {
  LLCP_TRACE_API1("LLCP_GetRemoteLSC () LSC:0x%x",
                  (llcp_cb.lcb.link_state == LLCP_LINK_STATE_ACTIVATED)
                      ? llcp_cb.lcb.peer_opt & (LLCP_LSC_1 | LLCP_LSC_2)
                      : 0);

  if (llcp_cb.lcb.link_state == LLCP_LINK_STATE_ACTIVATED)
    return (llcp_cb.lcb.peer_opt & (LLCP_LSC_1 | LLCP_LSC_2));
  else
    return (LLCP_LSC_UNKNOWN);
}

/*******************************************************************************
**
** Function         LLCP_GetRemoteVersion
**
** Description      Return LLCP version of connected device
**
**
** Returns          LLCP version
**
*******************************************************************************/
uint8_t LLCP_GetRemoteVersion(void) {
  LLCP_TRACE_API1("LLCP_GetRemoteVersion () Version: 0x%x",
                  (llcp_cb.lcb.link_state == LLCP_LINK_STATE_ACTIVATED)
                      ? llcp_cb.lcb.peer_version
                      : 0);

  if (llcp_cb.lcb.link_state == LLCP_LINK_STATE_ACTIVATED)
    return (llcp_cb.lcb.peer_version);
  else
    return 0;
}

/*******************************************************************************
**
** Function         LLCP_GetLinkMIU
**
** Description      Return local and remote link MIU
**
**
** Returns          None
**
*******************************************************************************/
void LLCP_GetLinkMIU(uint16_t* p_local_link_miu, uint16_t* p_remote_link_miu) {
  LLCP_TRACE_API0("LLCP_GetLinkMIU ()");

  if (llcp_cb.lcb.link_state == LLCP_LINK_STATE_ACTIVATED) {
    *p_local_link_miu = llcp_cb.lcb.local_link_miu;
    *p_remote_link_miu = llcp_cb.lcb.effective_miu;
  } else {
    *p_local_link_miu = 0;
    *p_remote_link_miu = 0;
  }

  LLCP_TRACE_DEBUG2(
      "LLCP_GetLinkMIU (): local_link_miu = %d, remote_link_miu = %d",
      *p_local_link_miu, *p_remote_link_miu);
}

/*******************************************************************************
**
** Function         LLCP_DiscoverService
**
** Description      Return SAP of service name in connected device through
**                  callback
**
**
** Returns          LLCP_STATUS_SUCCESS if success
**
*******************************************************************************/
tLLCP_STATUS LLCP_DiscoverService(char* p_name, tLLCP_SDP_CBACK* p_cback,
                                  uint8_t* p_tid) {
  tLLCP_STATUS status;
  uint8_t i;

  LLCP_TRACE_API1("LLCP_DiscoverService () Service Name:%s", p_name);

  if (llcp_cb.lcb.link_state != LLCP_LINK_STATE_ACTIVATED) {
    LLCP_TRACE_ERROR0("LLCP_DiscoverService (): Link is not activated");
    return LLCP_STATUS_FAIL;
  }

  if (!p_cback) {
    LLCP_TRACE_ERROR0("LLCP_DiscoverService (): Callback must be provided.");
    return LLCP_STATUS_FAIL;
  }

  /* if peer version is less than V1.1 then SNL is not supported */
  if ((llcp_cb.lcb.agreed_major_version == 0x01) &&
      (llcp_cb.lcb.agreed_minor_version < 0x01)) {
    LLCP_TRACE_ERROR0("LLCP_DiscoverService (): Peer doesn't support SNL");
    return LLCP_STATUS_FAIL;
  }

  for (i = 0; i < LLCP_MAX_SDP_TRANSAC; i++) {
    if (!llcp_cb.sdp_cb.transac[i].p_cback) {
      llcp_cb.sdp_cb.transac[i].tid = llcp_cb.sdp_cb.next_tid;
      llcp_cb.sdp_cb.next_tid++;
      llcp_cb.sdp_cb.transac[i].p_cback = p_cback;

      status = llcp_sdp_send_sdreq(llcp_cb.sdp_cb.transac[i].tid, p_name);

      if (status == LLCP_STATUS_FAIL) {
        llcp_cb.sdp_cb.transac[i].p_cback = NULL;
      }

      *p_tid = llcp_cb.sdp_cb.transac[i].tid;
      return (status);
    }
  }

  LLCP_TRACE_ERROR0("LLCP_DiscoverService (): Out of resource");

  return LLCP_STATUS_FAIL;
}