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Optimize ATSHA204 respose times

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Instead of shutting down the ATSHA between calls in a session,
it is put in idle state. This removes the need for a full resync
when the device is woken and that saves time which translate to
a quicker turnaround time for signed messages with HW signing.
To save power, it is still shut down when not in use.
This commit is contained in:
Patrick Fallberg
2016-06-12 15:37:45 +02:00
parent a5b0e8d8bb
commit 0a8aaedf8b
3 changed files with 49 additions and 37 deletions
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libraries/MySensors/core/MySigningAtsha204.cpp
+12 -6
View File
@@ -107,6 +107,7 @@ bool signerAtsha204GetNonce(MyMessage &msg) {
// Generate random number for use as nonce
// We used a basic whitening technique that XORs each byte in a 32byte random value with current hwMillis() counter
// This 32-byte random value is then hashed (SHA256) to produce the resulting nonce
(void)atsha204_wakeup(_signing_temp_message);
if (atsha204_execute(SHA204_RANDOM, RANDOM_SEED_UPDATE, 0, 0, NULL,
RANDOM_COUNT, _singning_tx_buffer, RANDOM_RSP_SIZE, _singning_rx_buffer) != SHA204_SUCCESS) {
DEBUG_SIGNING_PRINTBUF(F("Failed to generate nonce"), NULL, 0);
@@ -117,6 +118,8 @@ bool signerAtsha204GetNonce(MyMessage &msg) {
}
memcpy(_signing_current_nonce, signerSha256(_signing_current_nonce, 32), MAX_PAYLOAD);
atsha204_idle(); // We just idle the chip now since we expect to use it soon when the signed message arrives
// We set the part of the 32-byte nonce that does not fit into a message to 0xAA
memset(&_signing_current_nonce[MAX_PAYLOAD], 0xAA, sizeof(_signing_current_nonce)-MAX_PAYLOAD);
@@ -159,6 +162,9 @@ bool signerAtsha204SignMsg(MyMessage &msg) {
DEBUG_SIGNING_PRINTBUF(F("Signature salted with serial"), NULL, 0);
}
// Put device back to sleep
atsha204_sleep();
// Overwrite the first byte in the signature with the signing identifier
_singning_rx_buffer[SHA204_BUFFER_POS_DATA] = SIGNING_IDENTIFIER;
@@ -204,10 +210,15 @@ bool signerAtsha204VerifyMsg(MyMessage &msg) {
}
if (j == NUM_OF(_signing_whitelist)) {
DEBUG_SIGNING_PRINTBUF(F("Sender not found in whitelist, message rejected!"), NULL, 0);
// Put device back to sleep
atsha204_sleep();
return false;
}
#endif
// Put device back to sleep
atsha204_sleep();
// Overwrite the first byte in the signature with the signing identifier
_singning_rx_buffer[SHA204_BUFFER_POS_DATA] = SIGNING_IDENTIFIER;
@@ -227,6 +238,7 @@ bool signerAtsha204VerifyMsg(MyMessage &msg) {
// Helper to calculate signature of msg (returned in _singning_rx_buffer[SHA204_BUFFER_POS_DATA])
static void signerCalculateSignature(MyMessage &msg) {
(void)atsha204_wakeup(_signing_temp_message);
memset(_signing_temp_message, 0, 32);
memcpy(_signing_temp_message, (uint8_t*)&msg.data[1-HEADER_SIZE], MAX_MESSAGE_LENGTH-1-(MAX_PAYLOAD-mGetLength(msg)));
@@ -251,9 +263,6 @@ static void signerCalculateSignature(MyMessage &msg) {
(void)atsha204_execute(SHA204_HMAC, HMAC_MODE_SOURCE_FLAG_MATCH, 0, 0, NULL,
HMAC_COUNT, _singning_tx_buffer, HMAC_RSP_SIZE, _singning_rx_buffer);
// Put device back to sleep
atsha204_sleep();
DEBUG_SIGNING_PRINTBUF(F("HMAC: "), &_singning_rx_buffer[SHA204_BUFFER_POS_DATA], 32);
}
@@ -274,9 +283,6 @@ static uint8_t* signerSha256(const uint8_t* data, size_t sz) {
(void)atsha204_execute(SHA204_SHA, SHA_CALC, 0, SHA_MSG_SIZE, _signing_temp_message,
SHA_COUNT_LONG, _singning_tx_buffer, SHA_RSP_SIZE_LONG, _singning_rx_buffer);
// Put device back to sleep
atsha204_sleep();
DEBUG_SIGNING_PRINTBUF(F("SHA256: "), &_singning_rx_buffer[SHA204_BUFFER_POS_DATA], 32);
return &_singning_rx_buffer[SHA204_BUFFER_POS_DATA];
}
libraries/MySensors/drivers/ATSHA204/ATSHA204.cpp
+34 -30
View File
@@ -15,7 +15,6 @@ static uint8_t swi_send_bytes(uint8_t count, uint8_t *buffer);
static uint8_t swi_send_byte(uint8_t value);
static uint8_t sha204p_receive_response(uint8_t size, uint8_t *response);
static uint8_t sha204m_read(uint8_t *tx_buffer, uint8_t *rx_buffer, uint8_t zone, uint16_t address);
static uint8_t sha204c_wakeup(uint8_t *response);
static uint8_t sha204c_resync(uint8_t size, uint8_t *response);
static uint8_t sha204c_send_and_receive(uint8_t *tx_buffer, uint8_t rx_size, uint8_t *rx_buffer, uint8_t execution_delay, uint8_t execution_timeout);
@@ -218,34 +217,6 @@ static uint8_t sha204p_receive_response(uint8_t size, uint8_t *response)
/* Communication functions */
static uint8_t sha204c_wakeup(uint8_t *response)
{
swi_set_signal_pin(0);
delayMicroseconds(10*SHA204_WAKEUP_PULSE_WIDTH);
swi_set_signal_pin(1);
delay(SHA204_WAKEUP_DELAY);
uint8_t ret_code = sha204p_receive_response(SHA204_RSP_SIZE_MIN, response);
if (ret_code != SHA204_SUCCESS)
return ret_code;
// Verify status response.
if (response[SHA204_BUFFER_POS_COUNT] != SHA204_RSP_SIZE_MIN)
ret_code = SHA204_INVALID_SIZE;
else if (response[SHA204_BUFFER_POS_STATUS] != SHA204_STATUS_BYTE_WAKEUP)
ret_code = SHA204_COMM_FAIL;
else
{
if ((response[SHA204_RSP_SIZE_MIN - SHA204_CRC_SIZE] != 0x33)
|| (response[SHA204_RSP_SIZE_MIN + 1 - SHA204_CRC_SIZE] != 0x43))
ret_code = SHA204_BAD_CRC;
}
if (ret_code != SHA204_SUCCESS)
delay(SHA204_COMMAND_EXEC_MAX);
return ret_code;
}
static uint8_t sha204c_resync(uint8_t size, uint8_t *response)
{
// Try to re-synchronize without sending a Wake token
@@ -259,7 +230,7 @@ static uint8_t sha204c_resync(uint8_t size, uint8_t *response)
// to receive a response (steps 2 and 3 of the
// re-synchronization process).
atsha204_sleep();
ret_code = sha204c_wakeup(response);
ret_code = atsha204_wakeup(response);
// Translate a return value of success into one
// that indicates that the device had to be woken up
@@ -486,11 +457,44 @@ void atsha204_init(uint8_t pin)
#endif
}
void atsha204_idle(void)
{
swi_send_byte(SHA204_SWI_FLAG_IDLE);
}
void atsha204_sleep(void)
{
swi_send_byte(SHA204_SWI_FLAG_SLEEP);
}
uint8_t atsha204_wakeup(uint8_t *response)
{
swi_set_signal_pin(0);
delayMicroseconds(10*SHA204_WAKEUP_PULSE_WIDTH);
swi_set_signal_pin(1);
delay(SHA204_WAKEUP_DELAY);
uint8_t ret_code = sha204p_receive_response(SHA204_RSP_SIZE_MIN, response);
if (ret_code != SHA204_SUCCESS)
return ret_code;
// Verify status response.
if (response[SHA204_BUFFER_POS_COUNT] != SHA204_RSP_SIZE_MIN)
ret_code = SHA204_INVALID_SIZE;
else if (response[SHA204_BUFFER_POS_STATUS] != SHA204_STATUS_BYTE_WAKEUP)
ret_code = SHA204_COMM_FAIL;
else
{
if ((response[SHA204_RSP_SIZE_MIN - SHA204_CRC_SIZE] != 0x33)
|| (response[SHA204_RSP_SIZE_MIN + 1 - SHA204_CRC_SIZE] != 0x43))
ret_code = SHA204_BAD_CRC;
}
if (ret_code != SHA204_SUCCESS)
delay(SHA204_COMMAND_EXEC_MAX);
return ret_code;
}
uint8_t atsha204_execute(uint8_t op_code, uint8_t param1, uint16_t param2,
uint8_t datalen1, uint8_t *data1, uint8_t tx_size, uint8_t *tx_buffer, uint8_t rx_size, uint8_t *rx_buffer)
{
libraries/MySensors/drivers/ATSHA204/ATSHA204.h
+3 -1
View File
@@ -3,7 +3,7 @@
#if !DOXYGEN
#include "Arduino.h"
/* This is a scaled down variant of the ATSHA204 library, tweaked to meet the specific needs of MySensors. */
/* This is a scaled down variant of the ATSHA204 library, tweaked to meet the specific needs of the MySensors library. */
/* Library return codes */
#define SHA204_SUCCESS ((uint8_t) 0x00) //!< Function succeeded.
@@ -240,7 +240,9 @@
#endif
void atsha204_init(uint8_t pin);
void atsha204_idle(void);
void atsha204_sleep(void);
uint8_t atsha204_wakeup(uint8_t *response);
uint8_t atsha204_execute(uint8_t op_code, uint8_t param1, uint16_t param2,
uint8_t datalen1, uint8_t *data1, uint8_t tx_size,
uint8_t *tx_buffer, uint8_t rx_size, uint8_t *rx_buffer);