kopia lustrzana https://github.com/pjalocha/esp32-ogn-tracker
249 wiersze
7.8 KiB
C
249 wiersze
7.8 KiB
C
/*
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* Copyright (C) 2015-2017 Alibaba Group Holding Limited
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*/
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/*
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/ _____) _ | |
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( (____ _____ ____ _| |_ _____ ____| |__
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\____ \| ___ | (_ _) ___ |/ ___) _ \
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_____) ) ____| | | || |_| ____( (___| | | |
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(______/|_____)_|_|_| \__)_____)\____)_| |_|
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(C)2013 Semtech
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___ _____ _ ___ _ _____ ___ ___ ___ ___
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/ __|_ _/_\ / __| |/ / __/ _ \| _ \/ __| __|
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\__ \ | |/ _ \ (__| ' <| _| (_) | / (__| _|
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|___/ |_/_/ \_\___|_|\_\_| \___/|_|_\\___|___|
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embedded.connectivity.solutions===============
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Description: LoRa MAC layer implementation
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License: Revised BSD License, see LICENSE.TXT file include in the project
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Maintainer: Miguel Luis ( Semtech ), Gregory Cristian ( Semtech ) and Daniel Jaeckle ( STACKFORCE )
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*/
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#include <stdlib.h>
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#include <stdint.h>
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#include "cmacutil.h"
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#include "aes.h"
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#include "cmac.h"
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#include "LoRaMacCrypto.h"
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/*!
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* CMAC/AES Message Integrity Code (MIC) Block B0 size
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*/
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#define LORAMAC_MIC_BLOCK_B0_SIZE 16
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/*!
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* MIC field computation initial data
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*/
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static uint8_t MicBlockB0[] = { 0x49, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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};
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/*!
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* Contains the computed MIC field.
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*
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* \remark Only the 4 first bytes are used
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*/
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static uint8_t Mic[16];
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/*!
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* Encryption aBlock and sBlock
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*/
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static uint8_t aBlock[] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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};
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static uint8_t sBlock[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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};
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/*!
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* AES computation context variable
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*/
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static aes_context AesContext;
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/*!
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* CMAC computation context variable
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*/
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static AES_CMAC_CTX AesCmacCtx[1];
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/*!
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* \brief Computes the LoRaMAC frame MIC field
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*
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* \param [IN] buffer Data buffer
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* \param [IN] size Data buffer size
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* \param [IN] key AES key to be used
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* \param [IN] address Frame address
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* \param [IN] dir Frame direction [0: uplink, 1: downlink]
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* \param [IN] sequenceCounter Frame sequence counter
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* \param [OUT] mic Computed MIC field
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*/
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void LoRaMacComputeMic( const uint8_t *buffer, uint16_t size, const uint8_t *key, uint32_t address, uint8_t dir, uint32_t sequenceCounter, uint32_t *mic )
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{
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MicBlockB0[0] = 0x49; // these are already preloade but you never know...
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MicBlockB0[1] = 0x00;
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MicBlockB0[2] = 0x00;
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MicBlockB0[3] = 0x00;
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MicBlockB0[4] = 0x00;
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MicBlockB0[5] = dir;
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MicBlockB0[6] = ( address ) & 0xFF;
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MicBlockB0[7] = ( address >> 8 ) & 0xFF;
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MicBlockB0[8] = ( address >> 16 ) & 0xFF;
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MicBlockB0[9] = ( address >> 24 ) & 0xFF;
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MicBlockB0[10] = ( sequenceCounter ) & 0xFF;
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MicBlockB0[11] = ( sequenceCounter >> 8 ) & 0xFF;
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MicBlockB0[12] = ( sequenceCounter >> 16 ) & 0xFF;
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MicBlockB0[13] = ( sequenceCounter >> 24 ) & 0xFF;
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MicBlockB0[14] = 0x00; // preloaded in principle, but ...
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MicBlockB0[15] = size & 0xFF;
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AES_CMAC_Init( AesCmacCtx );
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AES_CMAC_SetKey( AesCmacCtx, key );
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AES_CMAC_Update( AesCmacCtx, MicBlockB0, LORAMAC_MIC_BLOCK_B0_SIZE );
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AES_CMAC_Update( AesCmacCtx, buffer, size & 0xFF );
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AES_CMAC_Final( Mic, AesCmacCtx );
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*mic = ( uint32_t )( ( uint32_t )Mic[3] << 24 | ( uint32_t )Mic[2] << 16 | ( uint32_t )Mic[1] << 8 | ( uint32_t )Mic[0] );
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}
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void LoRaMacPayloadEncrypt( const uint8_t *buffer, uint16_t size, const uint8_t *key, uint32_t address, uint8_t dir, uint32_t sequenceCounter, uint8_t *encBuffer )
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{
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uint16_t i;
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uint8_t bufferIndex = 0;
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uint16_t ctr = 1;
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memset1( AesContext.ksch, '\0', 240 );
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lorawan_aes_set_key( key, 16, &AesContext );
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aBlock[5] = dir;
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aBlock[6] = ( address ) & 0xFF;
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aBlock[7] = ( address >> 8 ) & 0xFF;
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aBlock[8] = ( address >> 16 ) & 0xFF;
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aBlock[9] = ( address >> 24 ) & 0xFF;
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aBlock[10] = ( sequenceCounter ) & 0xFF;
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aBlock[11] = ( sequenceCounter >> 8 ) & 0xFF;
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aBlock[12] = ( sequenceCounter >> 16 ) & 0xFF;
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aBlock[13] = ( sequenceCounter >> 24 ) & 0xFF;
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while( size >= 16 )
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{
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aBlock[15] = ( ( ctr ) & 0xFF );
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ctr++;
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lora_aes_encrypt( aBlock, sBlock, &AesContext );
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for( i = 0; i < 16; i++ )
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{
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encBuffer[bufferIndex + i] = buffer[bufferIndex + i] ^ sBlock[i];
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}
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size -= 16;
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bufferIndex += 16;
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}
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if( size > 0 )
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{
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aBlock[15] = ( ( ctr ) & 0xFF );
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lora_aes_encrypt( aBlock, sBlock, &AesContext );
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for( i = 0; i < size; i++ )
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{
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encBuffer[bufferIndex + i] = buffer[bufferIndex + i] ^ sBlock[i];
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}
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}
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}
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void LoRaMacPayloadDecrypt( const uint8_t *buffer, uint16_t size, const uint8_t *key, uint32_t address, uint8_t dir, uint32_t sequenceCounter, uint8_t *decBuffer )
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{
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LoRaMacPayloadEncrypt( buffer, size, key, address, dir, sequenceCounter, decBuffer );
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}
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void LoRaMacJoinComputeMic( const uint8_t *buffer, uint16_t size, const uint8_t *key, uint32_t *mic )
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{
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AES_CMAC_Init( AesCmacCtx );
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AES_CMAC_SetKey( AesCmacCtx, key );
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AES_CMAC_Update( AesCmacCtx, buffer, size & 0xFF );
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AES_CMAC_Final( Mic, AesCmacCtx );
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*mic = ( uint32_t )( ( uint32_t )Mic[3] << 24 | ( uint32_t )Mic[2] << 16 | ( uint32_t )Mic[1] << 8 | ( uint32_t )Mic[0] );
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}
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void LoRaMacJoinDecrypt( const uint8_t *buffer, uint16_t size, const uint8_t *key, uint8_t *decBuffer )
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{
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memset1( AesContext.ksch, '\0', 240 );
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lorawan_aes_set_key( key, 16, &AesContext );
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lora_aes_encrypt( buffer, decBuffer, &AesContext );
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// Check if optional CFList is included
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if( size >= 16 )
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{
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lora_aes_encrypt( buffer + 16, decBuffer + 16, &AesContext );
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}
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}
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void LoRaMacJoinComputeSKeys( const uint8_t *key, const uint8_t *appNonce, uint16_t devNonce, uint8_t *nwkSKey, uint8_t *appSKey )
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{
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uint8_t nonce[16];
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uint8_t *pDevNonce = ( uint8_t * )&devNonce;
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memset1( AesContext.ksch, '\0', 240 );
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lorawan_aes_set_key( key, 16, &AesContext );
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memset1( nonce, 0, sizeof( nonce ) );
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nonce[0] = 0x01;
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memcpy1( nonce + 1, appNonce, 6 );
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memcpy1( nonce + 7, pDevNonce, 2 );
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lora_aes_encrypt( nonce, nwkSKey, &AesContext );
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memset1( nonce, 0, sizeof( nonce ) );
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nonce[0] = 0x02;
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memcpy1( nonce + 1, appNonce, 6 );
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memcpy1( nonce + 7, pDevNonce, 2 );
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lora_aes_encrypt( nonce, appSKey, &AesContext );
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}
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void LoRaMacBeaconComputePingOffset( uint64_t beaconTime, uint32_t address, uint16_t pingPeriod, uint16_t *pingOffset )
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{
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uint8_t zeroKey[16];
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uint8_t buffer[16];
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uint8_t cipher[16];
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uint32_t result = 0;
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/* Refer to chapter 15.2 of the LoRaWAN specification v1.1. The beacon time
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* GPS time in seconds modulo 2^32
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*/
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uint32_t time = ( beaconTime % ( ( ( uint64_t ) 1 ) << 32 ) );
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memset1( zeroKey, 0, 16 );
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memset1( buffer, 0, 16 );
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memset1( cipher, 0, 16 );
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memset1( AesContext.ksch, '\0', 240 );
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buffer[0] = ( time ) & 0xFF;
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buffer[1] = ( time >> 8 ) & 0xFF;
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buffer[2] = ( time >> 16 ) & 0xFF;
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buffer[3] = ( time >> 24 ) & 0xFF;
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buffer[4] = ( address ) & 0xFF;
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buffer[5] = ( address >> 8 ) & 0xFF;
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buffer[6] = ( address >> 16 ) & 0xFF;
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buffer[7] = ( address >> 24 ) & 0xFF;
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lorawan_aes_set_key( zeroKey, 16, &AesContext );
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lora_aes_encrypt( buffer, cipher, &AesContext );
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result = ( ( ( uint32_t ) cipher[0] ) + ( ( ( uint32_t ) cipher[1] ) * 256 ) );
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*pingOffset = ( uint16_t )( result % pingPeriod );
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}
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