static bool gzp_key_update(void)
{
uint8_t tx_packet[GZP_CMD_KEY_UPDATE_PAYLOAD_LENGTH], rx_packet[GZP_MAX_ACK_PAYLOAD_LENGTH];
// Send "prepare packet" to get session token to be used for key update
tx_packet[0] = (uint8_t)GZP_CMD_KEY_UPDATE_PREPARE;
// If packet was successfully sent AND a response packet was received
if(gzp_tx_rx_transaction(tx_packet, GZP_CMD_KEY_UPDATE_PREPARE_PAYLOAD_LENGTH, rx_packet, NULL, GZP_DATA_PIPE) == GZP_TX_RX_SUCCESS)
{
if(rx_packet[0] == (uint8_t)GZP_CMD_KEY_UPDATE_PREPARE_RESP)
{
gzp_crypt_set_session_token(&rx_packet[GZP_CMD_KEY_UPDATE_PREPARE_RESP_SESSION_TOKEN]);
// Build "key update" packet
tx_packet[0] = (uint8_t)GZP_CMD_KEY_UPDATE;
gzp_add_validation_id(&tx_packet[GZP_CMD_KEY_UPDATE_VALIDATION_ID]);
gzp_random_numbers_generate(&tx_packet[GZP_CMD_KEY_UPDATE_NEW_KEY], GZP_DYN_KEY_LENGTH);
gzp_crypt_set_dyn_key(&tx_packet[GZP_CMD_KEY_UPDATE_NEW_KEY]);
// Encrypt "key update packet"
gzp_crypt_select_key(GZP_KEY_EXCHANGE);
gzp_crypt(&tx_packet[1], &tx_packet[1], GZP_CMD_KEY_UPDATE_PAYLOAD_LENGTH - 1);
// Send "key update" packet
if(gzp_tx_packet(tx_packet, GZP_CMD_KEY_UPDATE_PAYLOAD_LENGTH, GZP_DATA_PIPE))
{
return true;
}
}
}
return false;
}
static bool gzp_crypt_tx_transaction(const uint8_t *src, uint8_t length)
{
uint8_t tx_packet[GZLL_MAX_FW_PAYLOAD_LENGTH];
uint8_t rx_packet[GZLL_MAX_ACK_PAYLOAD_LENGTH];
uint8_t tx_packet_length;
tx_packet_length = length + GZP_USER_DATA_PACKET_OVERHEAD;
// Assemble tx packet
tx_packet[0] = GZP_CMD_ENCRYPTED_USER_DATA;
gzp_add_validation_id(&tx_packet[GZP_CMD_ENCRYPTED_USER_DATA_VALIDATION_ID]);
memcpy(&tx_packet[GZP_CMD_ENCRYPTED_USER_DATA_PAYLOAD], (uint8_t*)src, length);
// Encrypt tx packet
if(gzp_id_req_pending)
{
gzp_crypt_select_key(GZP_ID_EXCHANGE);
}
else
{
gzp_crypt_select_key(GZP_DATA_EXCHANGE);
}
gzp_crypt(&tx_packet[1], &tx_packet[1], tx_packet_length - 1);
// If packet was successfully sent AND a response packet was received
if(gzp_tx_rx_transaction(tx_packet, tx_packet_length, rx_packet, NULL, GZP_DATA_PIPE) == GZP_TX_RX_SUCCESS)
{
if(rx_packet[0] == GZP_CMD_ENCRYPTED_USER_DATA_RESP)
{
gzp_crypt(&rx_packet[GZP_CMD_ENCRYPTED_USER_DATA_RESP_VALIDATION_ID], &rx_packet[GZP_CMD_ENCRYPTED_USER_DATA_RESP_VALIDATION_ID], GZP_VALIDATION_ID_LENGTH);
// Validate response in order to know whether packet was correctly decrypted by host
if(gzp_validate_id(&rx_packet[GZP_CMD_ENCRYPTED_USER_DATA_RESP_VALIDATION_ID]))
{
// Update session token if normal operation (!gzp_id_req_pending)
if(!gzp_id_req_pending)
{
gzp_crypt_set_session_token(&rx_packet[GZP_CMD_ENCRYPTED_USER_DATA_RESP_SESSION_TOKEN]);
}
return true;
}
else
{
return false;
}
}
}
return false;
}
gzp_id_req_res_t gzp_id_req_send()
{
uint8_t tx_packet[GZP_CMD_HOST_ID_REQ_PAYLOAD_LENGTH];
uint8_t rx_packet[GZP_MAX_ACK_PAYLOAD_LENGTH];
gzp_tx_rx_trans_result_t trans_result;
// If no ID request is pending, send new "ID request"
if(!gzp_id_req_pending)
{
// Build "Host ID request packet"
tx_packet[0] = (uint8_t)GZP_CMD_HOST_ID_REQ;
// Generate new session token
gzp_random_numbers_generate(&tx_packet[GZP_CMD_HOST_ID_REQ_SESSION_TOKEN], GZP_SESSION_TOKEN_LENGTH);
// Send "Host ID request"
if(gzp_tx_packet(tx_packet, GZP_CMD_HOST_ID_REQ_PAYLOAD_LENGTH, GZP_DATA_PIPE))
{
// Update session token if "Host ID request" was successfully transmitted
gzp_crypt_set_session_token(&tx_packet[GZP_CMD_HOST_ID_REQ_SESSION_TOKEN]);
gzp_id_req_pending = true;
return GZP_ID_RESP_PENDING;
}
}
else // If "ID request is pending" send "fetch ID" packet
{
// Build "host ID fetch" packet
tx_packet[0] = (uint8_t)GZP_CMD_HOST_ID_FETCH;
gzp_add_validation_id(&tx_packet[GZP_CMD_HOST_ID_FETCH_VALIDATION_ID]);
// Encrypt "host ID fetch" packet
gzp_crypt_select_key(GZP_ID_EXCHANGE);
gzp_crypt(&tx_packet[1], &tx_packet[1], GZP_CMD_HOST_ID_FETCH_PAYLOAD_LENGTH - 1);
trans_result = gzp_tx_rx_transaction(tx_packet, GZP_CMD_HOST_ID_FETCH_PAYLOAD_LENGTH, rx_packet, NULL, GZP_DATA_PIPE);
// If packet was successfully sent AND a response packet was received
if(trans_result == GZP_TX_RX_SUCCESS)
{
// Validate response packet
if(rx_packet[0] == (uint8_t)GZP_CMD_HOST_ID_FETCH_RESP)
{
gzp_crypt(&rx_packet[1], &rx_packet[1], GZP_CMD_HOST_ID_FETCH_RESP_PAYLOAD_LENGTH - 1);
if(gzp_validate_id(&rx_packet[GZP_CMD_HOST_ID_FETCH_RESP_VALIDATION_ID]))
{
switch(rx_packet[GZP_CMD_HOST_ID_FETCH_RESP_STATUS])
{
case GZP_ID_RESP_PENDING:
break;
case GZP_ID_RESP_REJECTED:
gzp_id_req_pending = false;
break;
case GZP_ID_RESP_GRANTED:
gzp_set_host_id(&rx_packet[GZP_CMD_HOST_ID_FETCH_RESP_HOST_ID]);
gzp_random_numbers_generate(dyn_key, GZP_DYN_KEY_LENGTH);
gzp_crypt_set_dyn_key(dyn_key);
#ifndef GZP_NV_STORAGE_DISABLE
(void)gzp_params_store(true);
#endif
gzp_id_req_pending = false;
break;
default:
break;
}
return (gzp_id_req_res_t)rx_packet[GZP_CMD_HOST_ID_FETCH_RESP_STATUS];
}
else
{
gzp_id_req_pending = false;
return GZP_ID_RESP_REJECTED;
}
}
}
}
gzp_id_req_pending = false;
return GZP_ID_RESP_FAILED;
}