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         .uuid = uuid.getShortUUID(),
00098         .type = BLE_UUID_TYPE_UNKNOWN /* to be set below */
00099     };
00100 
00101     if (uuid.shortOrLong() == UUID::UUID_TYPE_SHORT) {
00102         nordicUUID.type = BLE_UUID_TYPE_BLE;
00103     } else {
00104         if (!lookupConvertedUUIDTable(uuid.getBaseUUID(), &nordicUUID.type)) {
00105             nordicUUID.type = custom_add_uuid_base(uuid.getBaseUUID());
00106             addToConvertedUUIDTable(uuid.getBaseUUID(), nordicUUID.type);
00107         }
00108     }
00109 
00110     return nordicUUID;
00111 }
00112 
00113 /**************************************************************************/
00114 /*!
00115     @brief      Adds the base UUID to the custom service. All UUIDs used
00116                 by this service are based on this 128-bit UUID.
00117 
00118     @note       This UUID needs to be added to the SoftDevice stack before
00119                 adding the service's primary service via
00120                 'sd_ble_gatts_service_add'
00121 
00122     @param[in]  p_uuid_base   A pointer to the 128-bit UUID array (8*16)
00123 
00124     @returns    The UUID type.
00125                 A return value of 0 should be considered an error.
00126 
00127     @retval     0x00    BLE_UUID_TYPE_UNKNOWN
00128     @retval     0x01    BLE_UUID_TYPE_BLE
00129     @retval     0x02    BLE_UUID_TYPE_VENDOR_BEGIN
00130 
00131     @section EXAMPLE
00132     @code
00133 
00134     // Take note that bytes 2/3 are blank since these are used to identify
00135     // the primary service and individual characteristics
00136     #define CFG_CUSTOM_UUID_BASE  "\x6E\x40\x00\x00\xB5\xA3\xF3\x93\xE0\xA9\xE5\x0E\x24\xDC\xCA\x9E"
00137 
00138     uint8_t uuid_type = custom_add_uuid_base(CFG_CUSTOM_UUID_BASE);
00139     ASSERT(uuid_type > 0, ERROR_NOT_FOUND);
00140 
00141     // We can now safely add the primary service and any characteristics
00142     // for our custom service ...
00143 
00144     @endcode
00145 */
00146 /**************************************************************************/
00147 uint8_t custom_add_uuid_base(uint8_t const *const p_uuid_base)
00148 {
00149     ble_uuid128_t base_uuid;
00150     uint8_t       uuid_type = 0;
00151 
00152     /* Reverse the bytes since ble_uuid128_t is LSB */
00153     for (unsigned i = 0; i < LENGTH_OF_LONG_UUID; i++) {
00154         base_uuid.uuid128[i] = p_uuid_base[LENGTH_OF_LONG_UUID - 1 - i];
00155     }
00156 
00157     ASSERT_INT( ERROR_NONE, sd_ble_uuid_vs_add( &base_uuid, &uuid_type ), 0);
00158 
00159     return uuid_type;
00160 }
00161 
00162 /**************************************************************************/
00163 /*!
00164 
00165 */
00166 /**************************************************************************/
00167 error_t custom_decode_uuid_base(uint8_t const *const p_uuid_base,
00168                                 ble_uuid_t          *p_uuid)
00169 {
00170     LongUUIDBytes_t uuid_base_le;
00171 
00172     /* Reverse the bytes since ble_uuid128_t is LSB */
00173     for (uint8_t i = 0; i < LENGTH_OF_LONG_UUID; i++) {
00174         uuid_base_le[i] = p_uuid_base[LENGTH_OF_LONG_UUID - 1 - i];
00175     }
00176 
00177     ASSERT_STATUS( sd_ble_uuid_decode(LENGTH_OF_LONG_UUID, uuid_base_le, p_uuid));
00178 
00179     return ERROR_NONE;
00180 }
00181 
00182 /**************************************************************************/
00183 /*!
00184     @brief      Adds a new characteristic to the custom service, assigning
00185                 properties, a UUID add-on value, etc.
00186 
00187     @param[in]  service_handle
00188     @param[in]  p_uuid            The 16-bit value to add to the base UUID
00189                                   for this characteristic (normally >1
00190                                   since 1 is typically used by the primary
00191                                   service).
00192     @param[in]  char_props        The characteristic properties, as
00193                                   defined by ble_gatt_char_props_t
00194     @param[in]  max_length        The maximum length of this characeristic
00195     @param[in]  p_char_handle
00196 
00197     @returns
00198     @retval     ERROR_NONE        Everything executed normally
00199 */
00200 /**************************************************************************/
00201 error_t custom_add_in_characteristic(uint16_t    service_handle,
00202                                      ble_uuid_t *p_uuid,
00203                                      uint8_t     properties,
00204                                      uint8_t    *p_data,
00205                                      uint16_t    min_length,
00206                                      uint16_t    max_length,
00207                                      bool        readAuthorization,
00208                                      bool        writeAuthorization,
00209                                      ble_gatts_char_handles_t *p_char_handle)
00210 {
00211     /* Characteristic metadata */
00212     ble_gatts_attr_md_t   cccd_md;
00213     ble_gatt_char_props_t char_props;
00214 
00215     memcpy(&char_props, &properties, 1);
00216 
00217     if (char_props.notify || char_props.indicate) {
00218         /* Notification requires cccd */
00219         memclr_( &cccd_md, sizeof(ble_gatts_attr_md_t));
00220         cccd_md.vloc = BLE_GATTS_VLOC_STACK;
00221         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
00222         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);
00223     }
00224 
00225     ble_gatts_char_md_t char_md = {0};
00226 
00227     char_md.char_props = char_props;
00228     char_md.p_cccd_md  =
00229         (char_props.notify || char_props.indicate) ? &cccd_md : NULL;
00230 
00231     /* Attribute declaration */
00232     ble_gatts_attr_md_t attr_md = {0};
00233 
00234     attr_md.rd_auth = readAuthorization;
00235     attr_md.wr_auth = writeAuthorization;
00236 
00237     attr_md.vloc = BLE_GATTS_VLOC_STACK;
00238     attr_md.vlen = (min_length == max_length) ? 0 : 1;
00239 
00240     if (char_props.read || char_props.notify || char_props.indicate) {
00241         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
00242     }
00243 
00244     if (char_props.write || char_props.write_wo_resp) {
00245         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);
00246     }
00247 
00248     ble_gatts_attr_t attr_char_value = {0};
00249 
00250     attr_char_value.p_uuid    = p_uuid;
00251     attr_char_value.p_attr_md = &attr_md;
00252     attr_char_value.init_len  = min_length;
00253     attr_char_value.max_len   = max_length;
00254     attr_char_value.p_value   = p_data;
00255 
00256     ASSERT_STATUS ( sd_ble_gatts_characteristic_add(service_handle,
00257                                                     &char_md,
00258                                                     &attr_char_value,
00259                                                     p_char_handle));
00260 
00261     return ERROR_NONE;
00262 }
00263 
00264 
00265 
00266 /**************************************************************************/
00267 /*!
00268     @brief      Adds a new descriptor to the custom service, assigning
00269                 value, a UUID add-on value, etc.
00270 
00271     @param[in]  char_handle
00272     @param[in]  p_uuid            The 16-bit value to add to the base UUID
00273                                   for this descriptor (normally >1
00274                                   since 1 is typically used by the primary
00275                                   service).
00276     @param[in]  max_length        The maximum length of this descriptor
00277 
00278     @returns
00279     @retval     ERROR_NONE        Everything executed normally
00280 */
00281 /**************************************************************************/
00282 error_t custom_add_in_descriptor(uint16_t    char_handle,
00283                                              ble_uuid_t *p_uuid,
00284                                              uint8_t    *p_data,
00285                                              uint16_t    min_length,
00286                                              uint16_t    max_length,
00287                                              uint16_t   *p_desc_handle)
00288 {
00289     /* Descriptor metadata */
00290     ble_gatts_attr_md_t   desc_md = {0};
00291 
00292     desc_md.vloc = BLE_GATTS_VLOC_STACK;
00293     desc_md.vlen = (min_length == max_length) ? 0 : 1;
00294 
00295     /* Make it readable and writable */
00296     BLE_GAP_CONN_SEC_MODE_SET_OPEN(&desc_md.read_perm);
00297     BLE_GAP_CONN_SEC_MODE_SET_OPEN(&desc_md.write_perm);
00298 
00299     ble_gatts_attr_t attr_desc = {0};
00300 
00301     attr_desc.p_uuid    = p_uuid;
00302     attr_desc.p_attr_md = &desc_md;
00303     attr_desc.init_len  = min_length;
00304     attr_desc.max_len   = max_length;
00305     attr_desc.p_value   = p_data;
00306 
00307     ASSERT_STATUS ( sd_ble_gatts_descriptor_add(char_handle,
00308                                                 &attr_desc,
00309                                                 p_desc_handle));
00310 
00311     return ERROR_NONE;
00312 }