Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 1cefd0cb authored by Jakub Pawlowski's avatar Jakub Pawlowski
Browse files

Fall back to Read Request when reading Characteristic Extended Properties 

If Read Multiple Request is not supported, fall back to Read Request.

Test: Manually tested against device modified to not support Read
Multiple Request (GATT_REQ_READ_MULTI in gatt_server_handle_client_req
forced to return GATT_REQ_NOT_SUPPORTED)
Bug: 110864501

Change-Id: I262678c93f2c3e56832502d1f46542dfc97c7904
parent f67cc057

system/bta/gatt/bta_gattc_cache.cc

+28 −7
Original line number Diff line number Diff line
@@ -171,6 +171,15 @@ static void bta_gattc_explore_next_service(uint16_t conn_id, 
  const auto& descriptors =

      p_srvc_cb->pending_discovery.DescriptorHandlesToRead();

  if (!descriptors.empty()) {

    if (p_srvc_cb->read_multiple_not_supported) {

      tGATT_READ_PARAM read_param{

          .by_handle = {.handle = descriptors.front(),

                        .auth_req = GATT_AUTH_REQ_NONE}};

      GATTC_Read(conn_id, GATT_READ_BY_HANDLE, &read_param);

      // asynchronous continuation in bta_gattc_op_cmpl_during_discovery

      return;

    }



    // TODO(jpawlowski): as a limit we should use MTU/2 rather than

    // GATT_MAX_READ_MULTI_HANDLES

    /* each descriptor contains just 2 bytes, so response size is same as
@@ -187,8 +196,7 @@ static void bta_gattc_explore_next_service(uint16_t conn_id, 
           sizeof(uint16_t) * num_handles);

    GATTC_Read(conn_id, GATT_READ_MULTIPLE, &read_param);



    // asynchronous continuation in bta_gattc_op_cmpl_during_discovery, when

    // read is finished

    // asynchronous continuation in bta_gattc_op_cmpl_during_discovery

    return;

  }
@@ -356,21 +364,35 @@ void bta_gattc_op_cmpl_during_discovery(UNUSED_ATTR tBTA_GATTC_CLCB* p_clcb, 
    VLOG(1) << __func__ << ": op = " << +p_data->hdr.layer_specific;

    return;

  }



  // our read operation is finished.

  // TODO: check if we can get here when any other read operation i.e. initiated

  // by upper layer apps, can get us there.



  tBTA_GATTC_SERV* p_srvc_cb = p_clcb->p_srcb;

  const uint8_t status = p_data->op_cmpl.status;

  if (status != GATT_SUCCESS) {

    if (status == GATT_REQ_NOT_SUPPORTED) {

      // TODO: handle case when read multiple is not supported on remote device.



  if (status == GATT_REQ_NOT_SUPPORTED &&

      !p_srvc_cb->read_multiple_not_supported) {

    // can't do "read multiple request", fall back to "read request"

    p_srvc_cb->read_multiple_not_supported = true;

    bta_gattc_explore_next_service(p_clcb->bta_conn_id, p_srvc_cb);

    return;

  }



  if (status != GATT_SUCCESS) {

    LOG(WARNING) << "Discovery on server failed: " << loghex(status);

    bta_gattc_reset_discover_st(p_clcb->p_srcb, GATT_ERROR);

  }



  const tGATT_VALUE& att_value = p_data->op_cmpl.p_cmpl->att_value;

  if (!p_srvc_cb->read_multiple_not_supported && att_value.len != 2) {

    // Just one Characteristic Extended Properties value at a time in Read

    // Response

    LOG(WARNING) << __func__ << " Read Response should be just 2 bytes!";

    bta_gattc_reset_discover_st(p_clcb->p_srcb, GATT_ERROR);

  }



  // Parsing is same for "Read Multiple Response", and for "Read Response"

  const uint8_t* p = att_value.value;

  std::vector<uint16_t> value_of_descriptors;

  while (p < att_value.value + att_value.len) {
@@ -379,7 +401,6 @@ void bta_gattc_op_cmpl_during_discovery(UNUSED_ATTR tBTA_GATTC_CLCB* p_clcb, 
    value_of_descriptors.push_back(extended_properties);

  }



  tBTA_GATTC_SERV* p_srvc_cb = p_clcb->p_srcb;

  bool ret =

      p_srvc_cb->pending_discovery.SetValueOfDescriptors(value_of_descriptors);

  if (!ret) {

system/bta/gatt/bta_gattc_int.h

+4 −0
Original line number Diff line number Diff line
@@ -214,6 +214,10 @@ typedef struct { 


  gatt::DatabaseBuilder pending_discovery;



  /* used only during service discovery, when reading Extended Characteristic

   * Properties */

  bool read_multiple_not_supported;



  uint8_t srvc_hdl_chg; /* service handle change indication pending */

  uint16_t attr_index;  /* cahce NV saving/loading attribute index */