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LibrePilot/flight/UAVTalk/uavtalk.c
Stacey Sheldon 785a7ccd88 uavtalk: convert tx to use blocking send routines
The uavtalk layer was previously implementing a poor
version of packet fragmentation based on a hard-coded
max packet size.  Since this was hard-coded, there was
no guarantee that it would match the underlying devices.

Now that the COM layer sending routines support fragmentation,
remove fragmentation and use the COM layer directly.

This will support future buffer size reductions in the COM
layer.
2011-12-30 23:05:36 -05:00

764 lines
22 KiB
C

/**
******************************************************************************
* @addtogroup OpenPilotSystem OpenPilot System
* @{
* @addtogroup OpenPilotLibraries OpenPilot System Libraries
* @{
*
* @file uavtalk.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief UAVTalk library, implements to telemetry protocol. See the wiki for more details.
* This library should not be called directly by the application, it is only used by the
* Telemetry module.
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "openpilot.h"
#include "uavtalk_priv.h"
// Private functions
static int32_t objectTransaction(UAVTalkConnectionData *connection, UAVObjHandle objectId, uint16_t instId, uint8_t type, int32_t timeout);
static int32_t sendObject(UAVTalkConnectionData *connection, UAVObjHandle obj, uint16_t instId, uint8_t type);
static int32_t sendSingleObject(UAVTalkConnectionData *connection, UAVObjHandle obj, uint16_t instId, uint8_t type);
static int32_t sendNack(UAVTalkConnectionData *connection, uint32_t objId);
static int32_t receiveObject(UAVTalkConnectionData *connection, uint8_t type, uint32_t objId, uint16_t instId, uint8_t* data, int32_t length);
static void updateAck(UAVTalkConnectionData *connection, UAVObjHandle obj, uint16_t instId);
/**
* Initialize the UAVTalk library
* \param[in] connection UAVTalkConnection to be used
* \param[in] outputStream Function pointer that is called to send a data buffer
* \return 0 Success
* \return -1 Failure
*/
UAVTalkConnection UAVTalkInitialize(UAVTalkOutputStream outputStream)
{
// allocate object
UAVTalkConnectionData * connection = pvPortMalloc(sizeof(UAVTalkConnectionData));
if (!connection) return 0;
connection->canari = UAVTALK_CANARI;
connection->iproc.rxPacketLength = 0;
connection->iproc.state = UAVTALK_STATE_SYNC;
connection->outStream = outputStream;
connection->lock = xSemaphoreCreateRecursiveMutex();
connection->transLock = xSemaphoreCreateRecursiveMutex();
// allocate buffers
connection->rxBuffer = pvPortMalloc(UAVTALK_MAX_PACKET_LENGTH);
if (!connection->rxBuffer) return 0;
connection->txBuffer = pvPortMalloc(UAVTALK_MAX_PACKET_LENGTH);
if (!connection->txBuffer) return 0;
vSemaphoreCreateBinary(connection->respSema);
xSemaphoreTake(connection->respSema, 0); // reset to zero
UAVTalkResetStats( (UAVTalkConnection) connection );
return (UAVTalkConnection) connection;
}
/**
* Set the communication output stream
* \param[in] connection UAVTalkConnection to be used
* \param[in] outputStream Function pointer that is called to send a data buffer
* \return 0 Success
* \return -1 Failure
*/
int32_t UAVTalkSetOutputStream(UAVTalkConnection connectionHandle, UAVTalkOutputStream outputStream)
{
UAVTalkConnectionData *connection;
CHECKCONHANDLE(connectionHandle,connection,return -1);
// Lock
xSemaphoreTakeRecursive(connection->lock, portMAX_DELAY);
// set output stream
connection->outStream = outputStream;
// Release lock
xSemaphoreGiveRecursive(connection->lock);
return 0;
}
/**
* Get current output stream
* \param[in] connection UAVTalkConnection to be used
* @return UAVTarlkOutputStream the output stream used
*/
UAVTalkOutputStream UAVTalkGetOutputStream(UAVTalkConnection connectionHandle)
{
UAVTalkConnectionData *connection;
CHECKCONHANDLE(connectionHandle,connection,return NULL);
return connection->outStream;
}
/**
* Get communication statistics counters
* \param[in] connection UAVTalkConnection to be used
* @param[out] statsOut Statistics counters
*/
void UAVTalkGetStats(UAVTalkConnection connectionHandle, UAVTalkStats* statsOut)
{
UAVTalkConnectionData *connection;
CHECKCONHANDLE(connectionHandle,connection,return );
// Lock
xSemaphoreTakeRecursive(connection->lock, portMAX_DELAY);
// Copy stats
memcpy(statsOut, &connection->stats, sizeof(UAVTalkStats));
// Release lock
xSemaphoreGiveRecursive(connection->lock);
}
/**
* Reset the statistics counters.
* \param[in] connection UAVTalkConnection to be used
*/
void UAVTalkResetStats(UAVTalkConnection connectionHandle)
{
UAVTalkConnectionData *connection;
CHECKCONHANDLE(connectionHandle,connection,return);
// Lock
xSemaphoreTakeRecursive(connection->lock, portMAX_DELAY);
// Clear stats
memset(&connection->stats, 0, sizeof(UAVTalkStats));
// Release lock
xSemaphoreGiveRecursive(connection->lock);
}
/**
* Request an update for the specified object, on success the object data would have been
* updated by the GCS.
* \param[in] connection UAVTalkConnection to be used
* \param[in] obj Object to update
* \param[in] instId The instance ID or UAVOBJ_ALL_INSTANCES for all instances.
* \param[in] timeout Time to wait for the response, when zero it will return immediately
* \return 0 Success
* \return -1 Failure
*/
int32_t UAVTalkSendObjectRequest(UAVTalkConnection connectionHandle, UAVObjHandle obj, uint16_t instId, int32_t timeout)
{
UAVTalkConnectionData *connection;
CHECKCONHANDLE(connectionHandle,connection,return -1);
return objectTransaction(connection, obj, instId, UAVTALK_TYPE_OBJ_REQ, timeout);
}
/**
* Send the specified object through the telemetry link.
* \param[in] connection UAVTalkConnection to be used
* \param[in] obj Object to send
* \param[in] instId The instance ID or UAVOBJ_ALL_INSTANCES for all instances.
* \param[in] acked Selects if an ack is required (1:ack required, 0: ack not required)
* \param[in] timeoutMs Time to wait for the ack, when zero it will return immediately
* \return 0 Success
* \return -1 Failure
*/
int32_t UAVTalkSendObject(UAVTalkConnection connectionHandle, UAVObjHandle obj, uint16_t instId, uint8_t acked, int32_t timeoutMs)
{
UAVTalkConnectionData *connection;
CHECKCONHANDLE(connectionHandle,connection,return -1);
// Send object
if (acked == 1)
{
return objectTransaction(connection, obj, instId, UAVTALK_TYPE_OBJ_ACK, timeoutMs);
}
else
{
return objectTransaction(connection, obj, instId, UAVTALK_TYPE_OBJ, timeoutMs);
}
}
/**
* Execute the requested transaction on an object.
* \param[in] connection UAVTalkConnection to be used
* \param[in] obj Object
* \param[in] instId The instance ID of UAVOBJ_ALL_INSTANCES for all instances.
* \param[in] type Transaction type
* UAVTALK_TYPE_OBJ: send object,
* UAVTALK_TYPE_OBJ_REQ: request object update
* UAVTALK_TYPE_OBJ_ACK: send object with an ack
* \return 0 Success
* \return -1 Failure
*/
static int32_t objectTransaction(UAVTalkConnectionData *connection, UAVObjHandle obj, uint16_t instId, uint8_t type, int32_t timeoutMs)
{
int32_t respReceived;
// Send object depending on if a response is needed
if (type == UAVTALK_TYPE_OBJ_ACK || type == UAVTALK_TYPE_OBJ_REQ)
{
// Get transaction lock (will block if a transaction is pending)
xSemaphoreTakeRecursive(connection->transLock, portMAX_DELAY);
// Send object
xSemaphoreTakeRecursive(connection->lock, portMAX_DELAY);
connection->respObj = obj;
connection->respInstId = instId;
sendObject(connection, obj, instId, type);
xSemaphoreGiveRecursive(connection->lock);
// Wait for response (or timeout)
respReceived = xSemaphoreTake(connection->respSema, timeoutMs/portTICK_RATE_MS);
// Check if a response was received
if (respReceived == pdFALSE)
{
// Cancel transaction
xSemaphoreTakeRecursive(connection->lock, portMAX_DELAY);
xSemaphoreTake(connection->respSema, 0); // non blocking call to make sure the value is reset to zero (binary sema)
connection->respObj = 0;
xSemaphoreGiveRecursive(connection->lock);
xSemaphoreGiveRecursive(connection->transLock);
return -1;
}
else
{
xSemaphoreGiveRecursive(connection->transLock);
return 0;
}
}
else if (type == UAVTALK_TYPE_OBJ)
{
xSemaphoreTakeRecursive(connection->lock, portMAX_DELAY);
sendObject(connection, obj, instId, UAVTALK_TYPE_OBJ);
xSemaphoreGiveRecursive(connection->lock);
return 0;
}
else
{
return -1;
}
}
/**
* Process an byte from the telemetry stream.
* \param[in] connection UAVTalkConnection to be used
* \param[in] rxbyte Received byte
* \return 0 Success
* \return -1 Failure
*/
int32_t UAVTalkProcessInputStream(UAVTalkConnection connectionHandle, uint8_t rxbyte)
{
UAVTalkConnectionData *connection;
CHECKCONHANDLE(connectionHandle,connection,return -1);
UAVTalkInputProcessor *iproc = &connection->iproc;
++connection->stats.rxBytes;
if (iproc->rxPacketLength < 0xffff)
iproc->rxPacketLength++; // update packet byte count
// Receive state machine
switch (iproc->state)
{
case UAVTALK_STATE_SYNC:
if (rxbyte != UAVTALK_SYNC_VAL)
break;
// Initialize and update the CRC
iproc->cs = PIOS_CRC_updateByte(0, rxbyte);
iproc->rxPacketLength = 1;
iproc->state = UAVTALK_STATE_TYPE;
break;
case UAVTALK_STATE_TYPE:
// update the CRC
iproc->cs = PIOS_CRC_updateByte(iproc->cs, rxbyte);
if ((rxbyte & UAVTALK_TYPE_MASK) != UAVTALK_TYPE_VER)
{
iproc->state = UAVTALK_STATE_SYNC;
break;
}
iproc->type = rxbyte;
iproc->packet_size = 0;
iproc->state = UAVTALK_STATE_SIZE;
iproc->rxCount = 0;
break;
case UAVTALK_STATE_SIZE:
// update the CRC
iproc->cs = PIOS_CRC_updateByte(iproc->cs, rxbyte);
if (iproc->rxCount == 0)
{
iproc->packet_size += rxbyte;
iproc->rxCount++;
break;
}
iproc->packet_size += rxbyte << 8;
if (iproc->packet_size < UAVTALK_MIN_HEADER_LENGTH || iproc->packet_size > UAVTALK_MAX_HEADER_LENGTH + UAVTALK_MAX_PAYLOAD_LENGTH)
{ // incorrect packet size
iproc->state = UAVTALK_STATE_SYNC;
break;
}
iproc->rxCount = 0;
iproc->objId = 0;
iproc->state = UAVTALK_STATE_OBJID;
break;
case UAVTALK_STATE_OBJID:
// update the CRC
iproc->cs = PIOS_CRC_updateByte(iproc->cs, rxbyte);
iproc->objId += rxbyte << (8*(iproc->rxCount++));
if (iproc->rxCount < 4)
break;
// Search for object, if not found reset state machine
// except if we got a OBJ_REQ for an object which does not
// exist, in which case we'll send a NACK
iproc->obj = UAVObjGetByID(iproc->objId);
if (iproc->obj == 0 && iproc->type != UAVTALK_TYPE_OBJ_REQ)
{
connection->stats.rxErrors++;
iproc->state = UAVTALK_STATE_SYNC;
break;
}
// Determine data length
if (iproc->type == UAVTALK_TYPE_OBJ_REQ || iproc->type == UAVTALK_TYPE_ACK || iproc->type == UAVTALK_TYPE_NACK)
{
iproc->length = 0;
iproc->instanceLength = 0;
}
else
{
iproc->length = UAVObjGetNumBytes(iproc->obj);
iproc->instanceLength = (UAVObjIsSingleInstance(iproc->obj) ? 0 : 2);
}
// Check length and determine next state
if (iproc->length >= UAVTALK_MAX_PAYLOAD_LENGTH)
{
connection->stats.rxErrors++;
iproc->state = UAVTALK_STATE_SYNC;
break;
}
// Check the lengths match
if ((iproc->rxPacketLength + iproc->instanceLength + iproc->length) != iproc->packet_size)
{ // packet error - mismatched packet size
connection->stats.rxErrors++;
iproc->state = UAVTALK_STATE_SYNC;
break;
}
iproc->instId = 0;
if (iproc->obj == 0)
{
// If this is a NACK, we skip to Checksum
iproc->state = UAVTALK_STATE_CS;
iproc->rxCount = 0;
}
// Check if this is a single instance object (i.e. if the instance ID field is coming next)
else if (UAVObjIsSingleInstance(iproc->obj))
{
// If there is a payload get it, otherwise receive checksum
if (iproc->length > 0)
iproc->state = UAVTALK_STATE_DATA;
else
iproc->state = UAVTALK_STATE_CS;
iproc->rxCount = 0;
}
else
{
iproc->state = UAVTALK_STATE_INSTID;
iproc->rxCount = 0;
}
break;
case UAVTALK_STATE_INSTID:
// update the CRC
iproc->cs = PIOS_CRC_updateByte(iproc->cs, rxbyte);
iproc->instId += rxbyte << (8*(iproc->rxCount++));
if (iproc->rxCount < 2)
break;
iproc->rxCount = 0;
// If there is a payload get it, otherwise receive checksum
if (iproc->length > 0)
iproc->state = UAVTALK_STATE_DATA;
else
iproc->state = UAVTALK_STATE_CS;
break;
case UAVTALK_STATE_DATA:
// update the CRC
iproc->cs = PIOS_CRC_updateByte(iproc->cs, rxbyte);
connection->rxBuffer[iproc->rxCount++] = rxbyte;
if (iproc->rxCount < iproc->length)
break;
iproc->state = UAVTALK_STATE_CS;
iproc->rxCount = 0;
break;
case UAVTALK_STATE_CS:
// the CRC byte
if (rxbyte != iproc->cs)
{ // packet error - faulty CRC
connection->stats.rxErrors++;
iproc->state = UAVTALK_STATE_SYNC;
break;
}
if (iproc->rxPacketLength != (iproc->packet_size + 1))
{ // packet error - mismatched packet size
connection->stats.rxErrors++;
iproc->state = UAVTALK_STATE_SYNC;
break;
}
xSemaphoreTakeRecursive(connection->lock, portMAX_DELAY);
receiveObject(connection, iproc->type, iproc->objId, iproc->instId, connection->rxBuffer, iproc->length);
connection->stats.rxObjectBytes += iproc->length;
connection->stats.rxObjects++;
xSemaphoreGiveRecursive(connection->lock);
iproc->state = UAVTALK_STATE_SYNC;
break;
default:
connection->stats.rxErrors++;
iproc->state = UAVTALK_STATE_SYNC;
}
// Done
return 0;
}
/**
* Receive an object. This function process objects received through the telemetry stream.
* \param[in] connection UAVTalkConnection to be used
* \param[in] type Type of received message (UAVTALK_TYPE_OBJ, UAVTALK_TYPE_OBJ_REQ, UAVTALK_TYPE_OBJ_ACK, UAVTALK_TYPE_ACK, UAVTALK_TYPE_NACK)
* \param[in] objId ID of the object to work on
* \param[in] instId The instance ID of UAVOBJ_ALL_INSTANCES for all instances.
* \param[in] data Data buffer
* \param[in] length Buffer length
* \return 0 Success
* \return -1 Failure
*/
static int32_t receiveObject(UAVTalkConnectionData *connection, uint8_t type, uint32_t objId, uint16_t instId, uint8_t* data, int32_t length)
{
UAVObjHandle obj;
int32_t ret = 0;
// Get the handle to the Object. Will be zero
// if object does not exist.
obj = UAVObjGetByID(objId);
// Process message type
switch (type) {
case UAVTALK_TYPE_OBJ:
// All instances, not allowed for OBJ messages
if (instId != UAVOBJ_ALL_INSTANCES)
{
// Unpack object, if the instance does not exist it will be created!
UAVObjUnpack(obj, instId, data);
// Check if an ack is pending
updateAck(connection, obj, instId);
}
else
{
ret = -1;
}
break;
case UAVTALK_TYPE_OBJ_ACK:
// All instances, not allowed for OBJ_ACK messages
if (instId != UAVOBJ_ALL_INSTANCES)
{
// Unpack object, if the instance does not exist it will be created!
if ( UAVObjUnpack(obj, instId, data) == 0 )
{
// Transmit ACK
sendObject(connection, obj, instId, UAVTALK_TYPE_ACK);
}
else
{
ret = -1;
}
}
else
{
ret = -1;
}
break;
case UAVTALK_TYPE_OBJ_REQ:
// Send requested object if message is of type OBJ_REQ
if (obj == 0)
sendNack(connection, objId);
else
sendObject(connection, obj, instId, UAVTALK_TYPE_OBJ);
break;
case UAVTALK_TYPE_NACK:
// Do nothing on flight side, let it time out.
break;
case UAVTALK_TYPE_ACK:
// All instances, not allowed for ACK messages
if (instId != UAVOBJ_ALL_INSTANCES)
{
// Check if an ack is pending
updateAck(connection, obj, instId);
}
else
{
ret = -1;
}
break;
default:
ret = -1;
}
// Done
return ret;
}
/**
* Check if an ack is pending on an object and give response semaphore
* \param[in] connection UAVTalkConnection to be used
* \param[in] obj Object
* \param[in] instId The instance ID of UAVOBJ_ALL_INSTANCES for all instances.
*/
static void updateAck(UAVTalkConnectionData *connection, UAVObjHandle obj, uint16_t instId)
{
if (connection->respObj == obj && (connection->respInstId == instId || connection->respInstId == UAVOBJ_ALL_INSTANCES))
{
xSemaphoreGive(connection->respSema);
connection->respObj = 0;
}
}
/**
* Send an object through the telemetry link.
* \param[in] connection UAVTalkConnection to be used
* \param[in] obj Object handle to send
* \param[in] instId The instance ID or UAVOBJ_ALL_INSTANCES for all instances
* \param[in] type Transaction type
* \return 0 Success
* \return -1 Failure
*/
static int32_t sendObject(UAVTalkConnectionData *connection, UAVObjHandle obj, uint16_t instId, uint8_t type)
{
uint32_t numInst;
uint32_t n;
// If all instances are requested and this is a single instance object, force instance ID to zero
if ( instId == UAVOBJ_ALL_INSTANCES && UAVObjIsSingleInstance(obj) )
{
instId = 0;
}
// Process message type
if ( type == UAVTALK_TYPE_OBJ || type == UAVTALK_TYPE_OBJ_ACK )
{
if (instId == UAVOBJ_ALL_INSTANCES)
{
// Get number of instances
numInst = UAVObjGetNumInstances(obj);
// Send all instances
for (n = 0; n < numInst; ++n)
{
sendSingleObject(connection, obj, n, type);
}
return 0;
}
else
{
return sendSingleObject(connection, obj, instId, type);
}
}
else if (type == UAVTALK_TYPE_OBJ_REQ)
{
return sendSingleObject(connection, obj, instId, UAVTALK_TYPE_OBJ_REQ);
}
else if (type == UAVTALK_TYPE_ACK)
{
if ( instId != UAVOBJ_ALL_INSTANCES )
{
return sendSingleObject(connection, obj, instId, UAVTALK_TYPE_ACK);
}
else
{
return -1;
}
}
else
{
return -1;
}
}
/**
* Send an object through the telemetry link.
* \param[in] connection UAVTalkConnection to be used
* \param[in] obj Object handle to send
* \param[in] instId The instance ID (can NOT be UAVOBJ_ALL_INSTANCES, use sendObject() instead)
* \param[in] type Transaction type
* \return 0 Success
* \return -1 Failure
*/
static int32_t sendSingleObject(UAVTalkConnectionData *connection, UAVObjHandle obj, uint16_t instId, uint8_t type)
{
int32_t length;
int32_t dataOffset;
uint32_t objId;
if (!connection->outStream) return -1;
// Setup type and object id fields
objId = UAVObjGetID(obj);
connection->txBuffer[0] = UAVTALK_SYNC_VAL; // sync byte
connection->txBuffer[1] = type;
// data length inserted here below
connection->txBuffer[4] = (uint8_t)(objId & 0xFF);
connection->txBuffer[5] = (uint8_t)((objId >> 8) & 0xFF);
connection->txBuffer[6] = (uint8_t)((objId >> 16) & 0xFF);
connection->txBuffer[7] = (uint8_t)((objId >> 24) & 0xFF);
// Setup instance ID if one is required
if (UAVObjIsSingleInstance(obj))
{
dataOffset = 8;
}
else
{
connection->txBuffer[8] = (uint8_t)(instId & 0xFF);
connection->txBuffer[9] = (uint8_t)((instId >> 8) & 0xFF);
dataOffset = 10;
}
// Determine data length
if (type == UAVTALK_TYPE_OBJ_REQ || type == UAVTALK_TYPE_ACK)
{
length = 0;
}
else
{
length = UAVObjGetNumBytes(obj);
}
// Check length
if (length >= UAVTALK_MAX_PAYLOAD_LENGTH)
{
return -1;
}
// Copy data (if any)
if (length > 0)
{
if ( UAVObjPack(obj, instId, &connection->txBuffer[dataOffset]) < 0 )
{
return -1;
}
}
// Store the packet length
connection->txBuffer[2] = (uint8_t)((dataOffset+length) & 0xFF);
connection->txBuffer[3] = (uint8_t)(((dataOffset+length) >> 8) & 0xFF);
// Calculate checksum
connection->txBuffer[dataOffset+length] = PIOS_CRC_updateCRC(0, connection->txBuffer, dataOffset+length);
uint16_t tx_msg_len = dataOffset+length+UAVTALK_CHECKSUM_LENGTH;
int32_t rc = (*connection->outStream)(connection->txBuffer, tx_msg_len);
if (rc == tx_msg_len) {
// Update stats
++connection->stats.txObjects;
connection->stats.txBytes += tx_msg_len;
connection->stats.txObjectBytes += length;
}
// Done
return 0;
}
/**
* Send a NACK through the telemetry link.
* \param[in] connection UAVTalkConnection to be used
* \param[in] objId Object ID to send a NACK for
* \return 0 Success
* \return -1 Failure
*/
static int32_t sendNack(UAVTalkConnectionData *connection, uint32_t objId)
{
int32_t dataOffset;
if (!connection->outStream) return -1;
connection->txBuffer[0] = UAVTALK_SYNC_VAL; // sync byte
connection->txBuffer[1] = UAVTALK_TYPE_NACK;
// data length inserted here below
connection->txBuffer[4] = (uint8_t)(objId & 0xFF);
connection->txBuffer[5] = (uint8_t)((objId >> 8) & 0xFF);
connection->txBuffer[6] = (uint8_t)((objId >> 16) & 0xFF);
connection->txBuffer[7] = (uint8_t)((objId >> 24) & 0xFF);
dataOffset = 8;
// Store the packet length
connection->txBuffer[2] = (uint8_t)((dataOffset) & 0xFF);
connection->txBuffer[3] = (uint8_t)(((dataOffset) >> 8) & 0xFF);
// Calculate checksum
connection->txBuffer[dataOffset] = PIOS_CRC_updateCRC(0, connection->txBuffer, dataOffset);
uint16_t tx_msg_len = dataOffset+UAVTALK_CHECKSUM_LENGTH;
int32_t rc = (*connection->outStream)(connection->txBuffer, tx_msg_len);
if (rc == tx_msg_len) {
// Update stats
connection->stats.txBytes += tx_msg_len;
}
// Done
return 0;
}
/**
* @}
* @}
*/