thread_beacon.c

00001 /*
00002  * Copyright (c) 2015-2019, Arm Limited and affiliates.
00003  * SPDX-License-Identifier: BSD-3-Clause
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions are met:
00007  *
00008  * 1. Redistributions of source code must retain the above copyright
00009  *    notice, this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright
00011  *    notice, this list of conditions and the following disclaimer in the
00012  *    documentation and/or other materials provided with the distribution.
00013  * 3. Neither the name of the copyright holder nor the
00014  *    names of its contributors may be used to endorse or promote products
00015  *    derived from this software without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
00018  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00019  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00020  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
00021  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
00022  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
00023  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00024  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00025  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
00026  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00027  * POSSIBILITY OF SUCH DAMAGE.
00028  */
00029 
00030 #include "nsconfig.h"
00031 #ifdef HAVE_THREAD
00032 #include "thread_beacon.h"
00033 #include "thread_config.h"
00034 #include "common_functions.h"
00035 #include "thread_meshcop_lib.h"
00036 #include <string.h>
00037 #include "ns_trace.h"
00038 /*service lib includes */
00039 #include "Service_Libs/utils/ns_crc.h"
00040 #define TRACE_GROUP "Tbcn"
00041 //#define TRACE_DEEP
00042 #ifdef TRACE_DEEP
00043 #define tr_deep   tr_debug
00044 #else
00045 #define tr_deep(...)
00046 #endif
00047 
00048 uint8_t *thread_beacon_calculate_bloom_filter(uint8_t *bloom_filter_ptr, uint8_t bloom_filter_length, uint8_t *joiner_id_ptr, int joiner_id_length)
00049 {
00050     uint8_t bloom_filter_bit_length = bloom_filter_length * 8;
00051 
00052     //Find the CRCCCITT and CRCANSI of joiner_id
00053     uint16_t crc_ccitt = crc16_ccitt(joiner_id_ptr, joiner_id_length);
00054     uint16_t crc_ansi = crc16_ansi(joiner_id_ptr, joiner_id_length);
00055     // byte location is calculated from left
00056     uint8_t byte_location_hash1 = (bloom_filter_length - ((crc_ccitt % bloom_filter_bit_length) / 8) - 1);
00057 
00058     // bit location is calculated from right within a byte
00059     uint8_t bit_location_hash1 = ((crc_ccitt % bloom_filter_bit_length) % 8);
00060     uint8_t bit_hash_1 = 1 << bit_location_hash1;
00061 
00062     uint8_t byte_location_hash2 = (bloom_filter_length - ((crc_ansi % bloom_filter_bit_length) / 8) - 1);
00063     uint8_t bit_location_hash2 = ((crc_ansi % bloom_filter_bit_length) % 8);
00064     uint8_t bit_hash_2 = 1 << bit_location_hash2;
00065 
00066     bloom_filter_ptr[byte_location_hash1] = bloom_filter_ptr[byte_location_hash1] | bit_hash_1;
00067     bloom_filter_ptr[byte_location_hash2] = bloom_filter_ptr[byte_location_hash2] | bit_hash_2;
00068 
00069     return bloom_filter_ptr;
00070 }
00071 
00072 #endif