custom_helper.cpp

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #include "custom_helper.h"
00018 
00019 /*
00020  * The current version of the soft-device doesn't handle duplicate 128-bit UUIDs
00021  * very  well. It is therefore necessary to filter away duplicates before
00022  * passing long UUIDs to sd_ble_uuid_vs_add(). The following types and data
00023  * structures involved in maintaining a local cache of 128-bit UUIDs.
00024  */
00025 typedef struct {
00026     LongUUIDBytes_t uuid;
00027     uint8_t         type;
00028 } converted_uuid_table_entry_t;
00029 static const unsigned UUID_TABLE_MAX_ENTRIES = 8; /* This is the maximum number of 128-bit UUIDs with distinct bases that
00030                                                    * we expect to be in use; increase this limit if needed. */
00031 static unsigned uuidTableEntries = 0; /* current usage of the table */
00032 converted_uuid_table_entry_t convertedUUIDTable[UUID_TABLE_MAX_ENTRIES];
00033 
00034 /**
00035  * lookup the cache of previously converted 128-bit UUIDs to find a type value.
00036  * @param  uuid          base 128-bit UUID
00037  * @param  recoveredType the type field of the 3-byte nRF's uuid.
00038  * @return               true if a match is found.
00039  */
00040 static bool
00041 lookupConvertedUUIDTable(const LongUUIDBytes_t uuid, uint8_t *recoveredType)
00042 {
00043     unsigned i;
00044     for (i = 0; i < uuidTableEntries; i++) {
00045         unsigned byteIndex;
00046         for (byteIndex = 0; byteIndex < LENGTH_OF_LONG_UUID; byteIndex++) {
00047             /* Skip bytes 2 and 3, because they contain the shortUUID (16-bit) version of the
00048              * long UUID; and we're comparing against the remainder. */
00049             if ((byteIndex == 2) || (byteIndex == 3)) {
00050                 continue;
00051             }
00052 
00053             if (convertedUUIDTable[i].uuid[byteIndex] != uuid[byteIndex]) {
00054                 break;
00055             }
00056         }
00057 
00058         if (byteIndex == LENGTH_OF_LONG_UUID) {
00059             *recoveredType = convertedUUIDTable[i].type;
00060             return true;
00061         }
00062     }
00063 
00064     return false;
00065 }
00066 
00067 static void
00068 addToConvertedUUIDTable(const LongUUIDBytes_t uuid, uint8_t type)
00069 {
00070     if (uuidTableEntries == UUID_TABLE_MAX_ENTRIES) {
00071         return; /* recovery needed; or at least the user should be warned about this fact.*/
00072     }
00073 
00074     memcpy(convertedUUIDTable[uuidTableEntries].uuid, uuid, LENGTH_OF_LONG_UUID);
00075     convertedUUIDTable[uuidTableEntries].uuid[2] = 0;
00076     convertedUUIDTable[uuidTableEntries].uuid[3] = 0;
00077     convertedUUIDTable[uuidTableEntries].type    = type;
00078     uuidTableEntries++;
00079 }
00080 
00081 /**
00082  * The nRF transport has its own 3-byte representation of a UUID. If the user-
00083  * specified UUID is 128-bits wide, then the UUID base needs to be added to the
00084  * soft-device and converted to a 3-byte handle before being used further. This
00085  * function is responsible for this translation of user-specified UUIDs into
00086  * nRF's representation.
00087  *
00088  * @param[in]  uuid
00089  *                 user-specified UUID
00090  * @return nRF
00091  *              3-byte UUID (containing a type and 16-bit UUID) representation
00092  *              to be used with SVC calls.
00093  */
00094 ble_uuid_t custom_convert_to_nordic_uuid(const UUID &uuid)
00095 {
00096     ble_uuid_t nordicUUID;
00097     nordicUUID.uuid = uuid.getShortUUID();
00098     nordicUUID.type = BLE_UUID_TYPE_UNKNOWN; /* to be set below */
00099 
00100     if (uuid.shortOrLong() == UUID::UUID_TYPE_SHORT) {
00101         nordicUUID.type = BLE_UUID_TYPE_BLE;
00102     } else {
00103         if (!lookupConvertedUUIDTable(uuid.getBaseUUID(), &nordicUUID.type)) {
00104             nordicUUID.type = custom_add_uuid_base(uuid.getBaseUUID());
00105             addToConvertedUUIDTable(uuid.getBaseUUID(), nordicUUID.type);
00106         }
00107     }
00108 
00109     return nordicUUID;
00110 }
00111 
00112 /**************************************************************************/
00113 /*!
00114     @brief      Adds the base UUID to the custom service. All UUIDs used
00115                 by this service are based on this 128-bit UUID.
00116 
00117     @note       This UUID needs to be added to the SoftDevice stack before
00118                 adding the service's primary service via
00119                 'sd_ble_gatts_service_add'
00120 
00121     @param[in]  p_uuid_base   A pointer to the 128-bit UUID array (8*16)
00122 
00123     @returns    The UUID type.
00124                 A return value of 0 should be considered an error.
00125 
00126     @retval     0x00    BLE_UUID_TYPE_UNKNOWN
00127     @retval     0x01    BLE_UUID_TYPE_BLE
00128     @retval     0x02    BLE_UUID_TYPE_VENDOR_BEGIN
00129 
00130     @section EXAMPLE
00131     @code
00132 
00133     // Take note that bytes 2/3 are blank since these are used to identify
00134     // the primary service and individual characteristics
00135     #define CFG_CUSTOM_UUID_BASE  "\x6E\x40\x00\x00\xB5\xA3\xF3\x93\xE0\xA9\xE5\x0E\x24\xDC\xCA\x9E"
00136 
00137     uint8_t uuid_type = custom_add_uuid_base(CFG_CUSTOM_UUID_BASE);
00138     ASSERT(uuid_type > 0, ERROR_NOT_FOUND);
00139 
00140     // We can now safely add the primary service and any characteristics
00141     // for our custom service ...
00142 
00143     @endcode
00144 */
00145 /**************************************************************************/
00146 uint8_t custom_add_uuid_base(uint8_t const *const p_uuid_base)
00147 {
00148     ble_uuid128_t base_uuid;
00149     uint8_t       uuid_type = 0;
00150 
00151     /* Reverse the bytes since ble_uuid128_t is LSB */
00152     for (unsigned i = 0; i < LENGTH_OF_LONG_UUID; i++) {
00153         base_uuid.uuid128[i] = p_uuid_base[LENGTH_OF_LONG_UUID - 1 - i];
00154     }
00155 
00156     ASSERT_INT( ERROR_NONE, sd_ble_uuid_vs_add( &base_uuid, &uuid_type ), 0);
00157 
00158     return uuid_type;
00159 }
00160 
00161 /**************************************************************************/
00162 /*!
00163 
00164 */
00165 /**************************************************************************/
00166 error_t custom_decode_uuid_base(uint8_t const *const p_uuid_base,
00167                                 ble_uuid_t          *p_uuid)
00168 {
00169     LongUUIDBytes_t uuid_base_le;
00170 
00171     /* Reverse the bytes since ble_uuid128_t is LSB */
00172     for (uint8_t i = 0; i < LENGTH_OF_LONG_UUID; i++) {
00173         uuid_base_le[i] = p_uuid_base[LENGTH_OF_LONG_UUID - 1 - i];
00174     }
00175 
00176     ASSERT_STATUS( sd_ble_uuid_decode(LENGTH_OF_LONG_UUID, uuid_base_le, p_uuid));
00177 
00178     return ERROR_NONE;
00179 }
00180 
00181 /**************************************************************************/
00182 /*!
00183     @brief      Adds a new characteristic to the custom service, assigning
00184                 properties, a UUID add-on value, etc.
00185 
00186     @param[in]  service_handle
00187     @param[in]  p_uuid            The 16-bit value to add to the base UUID
00188                                   for this characteristic (normally >1
00189                                   since 1 is typically used by the primary
00190                                   service).
00191     @param[in]  char_props        The characteristic properties, as
00192                                   defined by ble_gatt_char_props_t
00193     @param[in]  max_length        The maximum length of this characeristic
00194     @param[in]  p_char_handle
00195 
00196     @returns
00197     @retval     ERROR_NONE        Everything executed normally
00198 */
00199 /**************************************************************************/
00200 error_t custom_add_in_characteristic(uint16_t    service_handle,
00201                                      ble_uuid_t *p_uuid,
00202                                      uint8_t     properties,
00203                                      uint8_t    *p_data,
00204                                      uint16_t    min_length,
00205                                      uint16_t    max_length,
00206                                      bool        readAuthorization,
00207                                      bool        writeAuthorization,
00208                                      ble_gatts_char_handles_t *p_char_handle)
00209 {
00210     /* Characteristic metadata */
00211     ble_gatts_attr_md_t   cccd_md;
00212     ble_gatt_char_props_t char_props;
00213 
00214     memcpy(&char_props, &properties, 1);
00215 
00216     if (char_props.notify || char_props.indicate) {
00217         /* Notification requires cccd */
00218         memclr_( &cccd_md, sizeof(ble_gatts_attr_md_t));
00219         cccd_md.vloc = BLE_GATTS_VLOC_STACK;
00220         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
00221         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);
00222     }
00223 
00224     ble_gatts_char_md_t char_md = {0};
00225 
00226     char_md.char_props = char_props;
00227     char_md.p_cccd_md  =
00228         (char_props.notify || char_props.indicate) ? &cccd_md : NULL;
00229 
00230     /* Attribute declaration */
00231     ble_gatts_attr_md_t attr_md = {0};
00232 
00233     attr_md.rd_auth = readAuthorization;
00234     attr_md.wr_auth = writeAuthorization;
00235 
00236     attr_md.vloc = BLE_GATTS_VLOC_STACK;
00237     attr_md.vlen = (min_length == max_length) ? 0 : 1;
00238 
00239     if (char_props.read || char_props.notify || char_props.indicate) {
00240         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
00241     }
00242 
00243     if (char_props.write || char_props.write_wo_resp) {
00244         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);
00245     }
00246 
00247     ble_gatts_attr_t attr_char_value = {0};
00248 
00249     attr_char_value.p_uuid    = p_uuid;
00250     attr_char_value.p_attr_md = &attr_md;
00251     attr_char_value.init_len  = min_length;
00252     attr_char_value.max_len   = max_length;
00253     attr_char_value.p_value   = p_data;
00254 
00255     ASSERT_STATUS ( sd_ble_gatts_characteristic_add(service_handle,
00256                                                     &char_md,
00257                                                     &attr_char_value,
00258                                                     p_char_handle));
00259 
00260     return ERROR_NONE;
00261 }
00262 
00263 
00264 
00265 /**************************************************************************/
00266 /*!
00267     @brief      Adds a new descriptor to the custom service, assigning
00268                 value, a UUID add-on value, etc.
00269 
00270     @param[in]  char_handle
00271     @param[in]  p_uuid            The 16-bit value to add to the base UUID
00272                                   for this descriptor (normally >1
00273                                   since 1 is typically used by the primary
00274                                   service).
00275     @param[in]  max_length        The maximum length of this descriptor
00276 
00277     @returns
00278     @retval     ERROR_NONE        Everything executed normally
00279 */
00280 /**************************************************************************/
00281 error_t custom_add_in_descriptor(uint16_t    char_handle,
00282                                              ble_uuid_t *p_uuid,
00283                                              uint8_t    *p_data,
00284                                              uint16_t    min_length,
00285                                              uint16_t    max_length,
00286                                              uint16_t   *p_desc_handle)
00287 {
00288     /* Descriptor metadata */
00289     ble_gatts_attr_md_t   desc_md = {0};
00290 
00291     desc_md.vloc = BLE_GATTS_VLOC_STACK;
00292     desc_md.vlen = (min_length == max_length) ? 0 : 1;
00293 
00294     /* Make it readable and writable */
00295     BLE_GAP_CONN_SEC_MODE_SET_OPEN(&desc_md.read_perm);
00296     BLE_GAP_CONN_SEC_MODE_SET_OPEN(&desc_md.write_perm);
00297 
00298     ble_gatts_attr_t attr_desc = {0};
00299 
00300     attr_desc.p_uuid    = p_uuid;
00301     attr_desc.p_attr_md = &desc_md;
00302     attr_desc.init_len  = min_length;
00303     attr_desc.max_len   = max_length;
00304     attr_desc.p_value   = p_data;
00305 
00306     ASSERT_STATUS ( sd_ble_gatts_descriptor_add(char_handle,
00307                                                 &attr_desc,
00308                                                 p_desc_handle));
00309 
00310     return ERROR_NONE;
00311 }