btstack/src/ad_parser.c

/*
 * Copyright (C) 2014 BlueKitchen GmbH
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 * 4. Any redistribution, use, or modification is done solely for
 *    personal benefit and not for any commercial purpose or for
 *    monetary gain.
 *
 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN
 * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * Please inquire about commercial licensing options at 
 * contact@bluekitchen-gmbh.com
 *
 */

#define BTSTACK_FILE__ "ad_parser.c"


// *****************************************************************************
//
// Advertising Data Parser 
//
// *****************************************************************************

#include <stdint.h>
#include <string.h>

#include "bluetooth_data_types.h"
#include "btstack_util.h"
#include "hci.h"
#include "hci_cmd.h"

#include "ad_parser.h"

void ad_iterator_init(ad_context_t *context, uint8_t ad_len, const uint8_t * ad_data){
    context->data = ad_data;
    context->length = ad_len;
    context->offset = 0;
}

bool ad_iterator_has_more(const ad_context_t * context){
    // assert chunk_len and chunk_type are withing buffer
    if ((context->offset + 1u) >= context->length) {
        return false;
    }

    // assert chunk_len > 0
    uint8_t chunk_len = context->data[context->offset];
    if (chunk_len == 0u){
        return false;
    }
    
    // assert complete chunk fits into buffer
    if ((context->offset + 1u + chunk_len) > context->length) {
        return false;
    }
    return true;
}

// pre: ad_iterator_has_more() == 1
void ad_iterator_next(ad_context_t * context){
    uint8_t chunk_len = context->data[context->offset];
    context->offset += 1u + chunk_len;
}

uint8_t   ad_iterator_get_data_len(const ad_context_t * context){
    return context->data[context->offset] - 1u;
}

uint8_t   ad_iterator_get_data_type(const ad_context_t * context){
    return context->data[context->offset + 1u];
}

const uint8_t * ad_iterator_get_data(const ad_context_t * context){
    return &context->data[context->offset + 2u];
}

bool ad_data_contains_uuid16(uint8_t ad_len, const uint8_t * ad_data, uint16_t uuid16){
    ad_context_t context;
    ad_iterator_init(&context, ad_len, ad_data);
    while ( ad_iterator_has_more(&context) ){
        uint8_t data_type    = ad_iterator_get_data_type(&context);
        uint8_t data_len     = ad_iterator_get_data_len(&context);
        const uint8_t * data = ad_iterator_get_data(&context);
        
        uint8_t i;
        uint8_t ad_uuid128[16], uuid128_bt[16];
                
        switch (data_type){
            case BLUETOOTH_DATA_TYPE_INCOMPLETE_LIST_OF_16_BIT_SERVICE_CLASS_UUIDS:
            case BLUETOOTH_DATA_TYPE_COMPLETE_LIST_OF_16_BIT_SERVICE_CLASS_UUIDS:
                for (i=0u; (i + 2u) <= data_len; i+= 2u){
                    uint16_t uuid = (uint16_t) little_endian_read_16(data, (int) i);
                    if ( uuid == uuid16 ) {
                        return true;
                    }
                }
                break;
            case BLUETOOTH_DATA_TYPE_INCOMPLETE_LIST_OF_128_BIT_SERVICE_CLASS_UUIDS:
            case BLUETOOTH_DATA_TYPE_COMPLETE_LIST_OF_128_BIT_SERVICE_CLASS_UUIDS:
                uuid_add_bluetooth_prefix(ad_uuid128, uuid16);
                reverse_128(ad_uuid128, uuid128_bt);
                for (i=0u; (i + 16u) <= data_len; i += 16u){
                    if (memcmp(uuid128_bt, &data[i], 16) == 0){
                        return true;
                    };
                }
                break;
            default:
                break;
        }  
        ad_iterator_next(&context);
    }
    return false;
}

bool ad_data_contains_uuid128(uint8_t ad_len, const uint8_t * ad_data, const uint8_t * uuid128){
    ad_context_t context;
    // input in big endian/network order, bluetooth data in little endian
    uint8_t uuid128_le[16];
    reverse_128(uuid128, uuid128_le);
    ad_iterator_init(&context, ad_len, ad_data);
    while ( ad_iterator_has_more(&context) ){
        uint8_t data_type = ad_iterator_get_data_type(&context);
        uint8_t data_len  = ad_iterator_get_data_len(&context);
        const uint8_t * data = ad_iterator_get_data(&context);
        
        uint8_t i;
        uint8_t ad_uuid128[16];

        switch (data_type){
            case BLUETOOTH_DATA_TYPE_INCOMPLETE_LIST_OF_16_BIT_SERVICE_CLASS_UUIDS:
            case BLUETOOTH_DATA_TYPE_COMPLETE_LIST_OF_16_BIT_SERVICE_CLASS_UUIDS:
                for (i = 0u; (i+2u) <= data_len; i += 2u){
                    uint16_t uuid16 = little_endian_read_16(data, (int) i);
                    uuid_add_bluetooth_prefix(ad_uuid128, uuid16);
                    
                    if (memcmp(ad_uuid128, uuid128_le, 16) == 0) {
                        return true;
                    }
                }

                break;
            case BLUETOOTH_DATA_TYPE_INCOMPLETE_LIST_OF_128_BIT_SERVICE_CLASS_UUIDS:
            case BLUETOOTH_DATA_TYPE_COMPLETE_LIST_OF_128_BIT_SERVICE_CLASS_UUIDS:
                for (i = 0u; (i + 16u) <= data_len; i += 16u){
                  if (memcmp(uuid128_le, &data[i], 16) == 0) {
                      return true;
                  }
                }
                break;
            default:
                break;
        }  
        ad_iterator_next(&context);
    }
    return false;
}