B3M38SPD seminar project - beehive monitor with LoRa reporting
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/*
/ _____) _ | |
( (____ _____ ____ _| |_ _____ ____| |__
\____ \| ___ | (_ _) ___ |/ ___) _ \
_____) ) ____| | | || |_| ____( (___| | | |
(______/|_____)_|_|_| \__)_____)\____)_| |_|
(C)2013 Semtech
___ _____ _ ___ _ _____ ___ ___ ___ ___
/ __|_ _/_\ / __| |/ / __/ _ \| _ \/ __| __|
\__ \ | |/ _ \ (__| ' <| _| (_) | / (__| _|
|___/ |_/_/ \_\___|_|\_\_| \___/|_|_\\___|___|
embedded.connectivity.solutions===============
Description: LoRa MAC layer implementation
License: Revised BSD License, see LICENSE.TXT file include in the project
Maintainer: Miguel Luis ( Semtech ), Gregory Cristian ( Semtech ) and Daniel Jaeckle ( STACKFORCE )
*/
#include <stdlib.h>
#include <stdint.h>
#include "utilities.h"
#include "aes.h"
#include "cmac.h"
#include "LoRaMacCrypto.h"
/*!
* CMAC/AES Message Integrity Code (MIC) Block B0 size
*/
#define LORAMAC_MIC_BLOCK_B0_SIZE 16
/*!
* MIC field computation initial data
*/
static uint8_t MicBlockB0[] = { 0x49, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
/*!
* Contains the computed MIC field.
*
* \remark Only the 4 first bytes are used
*/
static uint8_t Mic[16];
/*!
* Encryption aBlock and sBlock
*/
static uint8_t aBlock[] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
static uint8_t sBlock[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
/*!
* AES computation context variable
*/
static aes_context AesContext;
/*!
* CMAC computation context variable
*/
static AES_CMAC_CTX AesCmacCtx[1];
/*!
* \brief Computes the LoRaMAC frame MIC field
*
* \param [IN] buffer Data buffer
* \param [IN] size Data buffer size
* \param [IN] key AES key to be used
* \param [IN] address Frame address
* \param [IN] dir Frame direction [0: uplink, 1: downlink]
* \param [IN] sequenceCounter Frame sequence counter
* \param [OUT] mic Computed MIC field
*/
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 )
{
MicBlockB0[5] = dir;
MicBlockB0[6] = ( address ) & 0xFF;
MicBlockB0[7] = ( address >> 8 ) & 0xFF;
MicBlockB0[8] = ( address >> 16 ) & 0xFF;
MicBlockB0[9] = ( address >> 24 ) & 0xFF;
MicBlockB0[10] = ( sequenceCounter ) & 0xFF;
MicBlockB0[11] = ( sequenceCounter >> 8 ) & 0xFF;
MicBlockB0[12] = ( sequenceCounter >> 16 ) & 0xFF;
MicBlockB0[13] = ( sequenceCounter >> 24 ) & 0xFF;
MicBlockB0[15] = size & 0xFF;
AES_CMAC_Init( AesCmacCtx );
AES_CMAC_SetKey( AesCmacCtx, key );
AES_CMAC_Update( AesCmacCtx, MicBlockB0, LORAMAC_MIC_BLOCK_B0_SIZE );
AES_CMAC_Update( AesCmacCtx, buffer, size & 0xFF );
AES_CMAC_Final( Mic, AesCmacCtx );
*mic = ( uint32_t )( ( uint32_t )Mic[3] << 24 | ( uint32_t )Mic[2] << 16 | ( uint32_t )Mic[1] << 8 | ( uint32_t )Mic[0] );
}
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 )
{
uint16_t i;
uint8_t bufferIndex = 0;
uint16_t ctr = 1;
memset1( AesContext.ksch, '\0', 240 );
aes_set_key( key, 16, &AesContext );
aBlock[5] = dir;
aBlock[6] = ( address ) & 0xFF;
aBlock[7] = ( address >> 8 ) & 0xFF;
aBlock[8] = ( address >> 16 ) & 0xFF;
aBlock[9] = ( address >> 24 ) & 0xFF;
aBlock[10] = ( sequenceCounter ) & 0xFF;
aBlock[11] = ( sequenceCounter >> 8 ) & 0xFF;
aBlock[12] = ( sequenceCounter >> 16 ) & 0xFF;
aBlock[13] = ( sequenceCounter >> 24 ) & 0xFF;
while( size >= 16 )
{
aBlock[15] = ( ( ctr ) & 0xFF );
ctr++;
aes_encrypt( aBlock, sBlock, &AesContext );
for( i = 0; i < 16; i++ )
{
encBuffer[bufferIndex + i] = buffer[bufferIndex + i] ^ sBlock[i];
}
size -= 16;
bufferIndex += 16;
}
if( size > 0 )
{
aBlock[15] = ( ( ctr ) & 0xFF );
aes_encrypt( aBlock, sBlock, &AesContext );
for( i = 0; i < size; i++ )
{
encBuffer[bufferIndex + i] = buffer[bufferIndex + i] ^ sBlock[i];
}
}
}
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 )
{
LoRaMacPayloadEncrypt( buffer, size, key, address, dir, sequenceCounter, decBuffer );
}
void LoRaMacJoinComputeMic( const uint8_t *buffer, uint16_t size, const uint8_t *key, uint32_t *mic )
{
AES_CMAC_Init( AesCmacCtx );
AES_CMAC_SetKey( AesCmacCtx, key );
AES_CMAC_Update( AesCmacCtx, buffer, size & 0xFF );
AES_CMAC_Final( Mic, AesCmacCtx );
*mic = ( uint32_t )( ( uint32_t )Mic[3] << 24 | ( uint32_t )Mic[2] << 16 | ( uint32_t )Mic[1] << 8 | ( uint32_t )Mic[0] );
}
void LoRaMacJoinDecrypt( const uint8_t *buffer, uint16_t size, const uint8_t *key, uint8_t *decBuffer )
{
memset1( AesContext.ksch, '\0', 240 );
aes_set_key( key, 16, &AesContext );
aes_encrypt( buffer, decBuffer, &AesContext );
// Check if optional CFList is included
if( size >= 16 )
{
aes_encrypt( buffer + 16, decBuffer + 16, &AesContext );
}
}
void LoRaMacJoinComputeSKeys( const uint8_t *key, const uint8_t *appNonce, uint16_t devNonce, uint8_t *nwkSKey, uint8_t *appSKey )
{
uint8_t nonce[16];
uint8_t *pDevNonce = ( uint8_t * )&devNonce;
memset1( AesContext.ksch, '\0', 240 );
aes_set_key( key, 16, &AesContext );
memset1( nonce, 0, sizeof( nonce ) );
nonce[0] = 0x01;
memcpy1( nonce + 1, appNonce, 6 );
memcpy1( nonce + 7, pDevNonce, 2 );
aes_encrypt( nonce, nwkSKey, &AesContext );
memset1( nonce, 0, sizeof( nonce ) );
nonce[0] = 0x02;
memcpy1( nonce + 1, appNonce, 6 );
memcpy1( nonce + 7, pDevNonce, 2 );
aes_encrypt( nonce, appSKey, &AesContext );
}