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     UUID::LongUUIDBytes_t uuid;
00027     uint8_t         type;
00028 } converted_uuid_table_entry_t;
00029 static const unsigned UUID_TABLE_MAX_ENTRIES = 4; /* 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 UUID::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 < UUID::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 == UUID::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 UUID::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, 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     for (unsigned i = 0; i < UUID::LENGTH_OF_LONG_UUID; i++) {
00152         base_uuid.uuid128[i] = p_uuid_base[i];
00153     }
00154 
00155     ASSERT_INT( ERROR_NONE, sd_ble_uuid_vs_add( &base_uuid, &uuid_type ), 0);
00156 
00157     return uuid_type;
00158 }
00159 
00160 /**************************************************************************/
00161 /*!
00162 
00163 */
00164 /**************************************************************************/
00165 error_t custom_decode_uuid_base(uint8_t const *const p_uuid_base,
00166                                 ble_uuid_t          *p_uuid)
00167 {
00168     UUID::LongUUIDBytes_t uuid_base_le;
00169 
00170     for (uint8_t i = 0; i < UUID::LENGTH_OF_LONG_UUID; i++) {
00171         uuid_base_le[i] = p_uuid_base[i];
00172     }
00173 
00174     ASSERT_STATUS( sd_ble_uuid_decode(UUID::LENGTH_OF_LONG_UUID, uuid_base_le, p_uuid));
00175 
00176     return ERROR_NONE;
00177 }
00178 
00179 /**************************************************************************/
00180 /*!
00181     @brief      Adds a new characteristic to the custom service, assigning
00182                 properties, a UUID add-on value, etc.
00183 
00184     @param[in]  service_handle
00185     @param[in]  p_uuid            The 16-bit value to add to the base UUID
00186                                   for this characteristic (normally >1
00187                                   since 1 is typically used by the primary
00188                                   service).
00189     @param[in]  char_props        The characteristic properties, as
00190                                   defined by ble_gatt_char_props_t
00191     @param[in]  max_length        The maximum length of this characeristic
00192     @param[in]  has_variable_len  Whether the characteristic data has
00193                                   variable length.
00194     @param[out] 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                                      SecurityManager::SecurityMode_t       requiredSecurity,
00204                                      uint8_t                  *p_data,
00205                                      uint16_t                  length,
00206                                      uint16_t                  max_length,
00207                                      bool                      has_variable_len,
00208                                      const uint8_t            *userDescriptionDescriptorValuePtr,
00209                                      uint16_t                  userDescriptionDescriptorValueLen,
00210                                      bool                      readAuthorization,
00211                                      bool                      writeAuthorization,
00212                                      ble_gatts_char_handles_t *p_char_handle)
00213 {
00214     /* Characteristic metadata */
00215     ble_gatts_attr_md_t   cccd_md;
00216     ble_gatt_char_props_t char_props;
00217 
00218     memcpy(&char_props, &properties, 1);
00219 
00220     if (char_props.notify || char_props.indicate) {
00221         /* Notification requires cccd */
00222         memclr_( &cccd_md, sizeof(ble_gatts_attr_md_t));
00223         cccd_md.vloc = BLE_GATTS_VLOC_STACK;
00224         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
00225         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);
00226     }
00227 
00228     ble_gatts_char_md_t char_md = {0};
00229 
00230     char_md.char_props = char_props;
00231     char_md.p_cccd_md  =
00232         (char_props.notify || char_props.indicate) ? &cccd_md : NULL;
00233     if ((userDescriptionDescriptorValueLen > 0) && (userDescriptionDescriptorValuePtr != NULL)) {
00234         char_md.p_char_user_desc        = const_cast<uint8_t *>(userDescriptionDescriptorValuePtr);
00235         char_md.char_user_desc_max_size = userDescriptionDescriptorValueLen;
00236         char_md.char_user_desc_size     = userDescriptionDescriptorValueLen;
00237     }
00238 
00239     /* Attribute declaration */
00240     ble_gatts_attr_md_t attr_md = {0};
00241 
00242     attr_md.rd_auth = readAuthorization;
00243     attr_md.wr_auth = writeAuthorization;
00244 
00245     attr_md.vloc = BLE_GATTS_VLOC_STACK;
00246     /* Always set variable size */
00247     attr_md.vlen = has_variable_len;
00248 
00249     if (char_props.read || char_props.notify || char_props.indicate) {
00250         switch (requiredSecurity) {
00251             case SecurityManager::SECURITY_MODE_ENCRYPTION_OPEN_LINK :
00252                 BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
00253                 break;
00254             case SecurityManager::SECURITY_MODE_ENCRYPTION_NO_MITM :
00255                 BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM(&attr_md.read_perm);
00256                 break;
00257             case SecurityManager::SECURITY_MODE_ENCRYPTION_WITH_MITM :
00258                 BLE_GAP_CONN_SEC_MODE_SET_ENC_WITH_MITM(&attr_md.read_perm);
00259                 break;
00260             case SecurityManager::SECURITY_MODE_SIGNED_NO_MITM :
00261                 BLE_GAP_CONN_SEC_MODE_SET_SIGNED_NO_MITM(&attr_md.read_perm);
00262                 break;
00263             case SecurityManager::SECURITY_MODE_SIGNED_WITH_MITM :
00264                 BLE_GAP_CONN_SEC_MODE_SET_SIGNED_WITH_MITM(&attr_md.read_perm);
00265                 break;
00266             default:
00267                 break;
00268         };
00269     }
00270 
00271     if (char_props.write || char_props.write_wo_resp) {
00272         switch (requiredSecurity) {
00273             case SecurityManager::SECURITY_MODE_ENCRYPTION_OPEN_LINK :
00274                 BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);
00275                 break;
00276             case SecurityManager::SECURITY_MODE_ENCRYPTION_NO_MITM :
00277                 BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM(&attr_md.write_perm);
00278                 break;
00279             case SecurityManager::SECURITY_MODE_ENCRYPTION_WITH_MITM :
00280                 BLE_GAP_CONN_SEC_MODE_SET_ENC_WITH_MITM(&attr_md.write_perm);
00281                 break;
00282             case SecurityManager::SECURITY_MODE_SIGNED_NO_MITM :
00283                 BLE_GAP_CONN_SEC_MODE_SET_SIGNED_NO_MITM(&attr_md.write_perm);
00284                 break;
00285             case SecurityManager::SECURITY_MODE_SIGNED_WITH_MITM :
00286                 BLE_GAP_CONN_SEC_MODE_SET_SIGNED_WITH_MITM(&attr_md.write_perm);
00287                 break;
00288             default:
00289                 break;
00290         };
00291     }
00292 
00293     ble_gatts_attr_t attr_char_value = {0};
00294 
00295     attr_char_value.p_uuid    = p_uuid;
00296     attr_char_value.p_attr_md = &attr_md;
00297     attr_char_value.init_len  = length;
00298     attr_char_value.max_len   = max_length;
00299     attr_char_value.p_value   = p_data;
00300 
00301     ASSERT_STATUS ( sd_ble_gatts_characteristic_add(service_handle,
00302                                                     &char_md,
00303                                                     &attr_char_value,
00304                                                     p_char_handle));
00305 
00306     return ERROR_NONE;
00307 }
00308 
00309 
00310 
00311 /**************************************************************************/
00312 /*!
00313     @brief      Adds a new descriptor to the custom service, assigning
00314                 value, a UUID add-on value, etc.
00315 
00316     @param[in]  char_handle
00317     @param[in]  p_uuid            The 16-bit value to add to the base UUID
00318                                   for this descriptor (normally >1
00319                                   since 1 is typically used by the primary
00320                                   service).
00321     @param[in]  max_length        The maximum length of this descriptor
00322     @param[in]  has_variable_len  Whether the characteristic data has
00323                                   variable length.
00324 
00325     @returns
00326     @retval     ERROR_NONE        Everything executed normally
00327 */
00328 /**************************************************************************/
00329 error_t custom_add_in_descriptor(uint16_t    char_handle,
00330                                  ble_uuid_t *p_uuid,
00331                                  uint8_t    *p_data,
00332                                  uint16_t    length,
00333                                  uint16_t    max_length,
00334                                  bool        has_variable_len,
00335                                  uint16_t   *p_desc_handle)
00336 {
00337     /* Descriptor metadata */
00338     ble_gatts_attr_md_t   desc_md = {0};
00339 
00340     desc_md.vloc = BLE_GATTS_VLOC_STACK;
00341     /* Always set variable size */
00342     desc_md.vlen = has_variable_len;
00343 
00344     /* Make it readable and writable */
00345     BLE_GAP_CONN_SEC_MODE_SET_OPEN(&desc_md.read_perm);
00346     BLE_GAP_CONN_SEC_MODE_SET_OPEN(&desc_md.write_perm);
00347 
00348     ble_gatts_attr_t attr_desc = {0};
00349 
00350     attr_desc.p_uuid    = p_uuid;
00351     attr_desc.p_attr_md = &desc_md;
00352     attr_desc.init_len  = length;
00353     attr_desc.max_len   = max_length;
00354     attr_desc.p_value   = p_data;
00355 
00356     ASSERT_STATUS ( sd_ble_gatts_descriptor_add(char_handle,
00357                                                 &attr_desc,
00358                                                 p_desc_handle));
00359 
00360     return ERROR_NONE;
00361 }