fsfw/datalinklayer/DataLinkLayer.cpp

#include "DataLinkLayer.h"
#include "../globalfunctions/CRC.h"
#include "../serviceinterface/ServiceInterfaceStream.h"

DataLinkLayer::DataLinkLayer(uint8_t* set_frame_buffer, ClcwIF* setClcw,
		uint8_t set_start_sequence_length, uint16_t set_scid) :
		spacecraftId(set_scid), frameBuffer(set_frame_buffer), clcw(setClcw), receivedDataLength(0), currentFrame(
				NULL), startSequenceLength(set_start_sequence_length) {
	//Nothing to do except from setting the values above.
}

DataLinkLayer::~DataLinkLayer() {

}

ReturnValue_t DataLinkLayer::frameDelimitingAndFillRemoval() {
	if ((receivedDataLength - startSequenceLength) < FRAME_PRIMARY_HEADER_LENGTH) {
		return SHORTER_THAN_HEADER;
	}
	//Removing start sequence.
	//SHOULDDO: Not implemented here.
	while ( *frameBuffer == START_SEQUENCE_PATTERN ) {
		frameBuffer++;
	}
	TcTransferFrame frame_candidate(frameBuffer);
	this->currentFrame = frame_candidate; //should work with shallow copy.

	return RETURN_OK;
}

ReturnValue_t DataLinkLayer::frameValidationCheck() {
	//Check TF_version number
	if (this->currentFrame.getVersionNumber() != FRAME_VERSION_NUMBER_DEFAULT) {
		return WRONG_TF_VERSION;
	}
	//Check SpaceCraft ID
	if (this->currentFrame.getSpacecraftId() != this->spacecraftId) {
		return WRONG_SPACECRAFT_ID;
	}
	//Check other header limitations:
	if (!this->currentFrame.bypassFlagSet() && this->currentFrame.controlCommandFlagSet()) {
		return NO_VALID_FRAME_TYPE;
	}
	//- Spares are zero
	if (!this->currentFrame.spareIsZero()) {
		return NO_VALID_FRAME_TYPE;
	}
	//Compare detected frame length with the one in the header
	uint16_t length = currentFrame.getFullSize();
	if (length > receivedDataLength) {
		//Frame is too long or just right
//		error << "frameValidationCheck: Too short.";
//		currentFrame.print();
		return TOO_SHORT;
	}
	if (USE_CRC) {
		return this->frameCheckCRC();
	}
	return RETURN_OK;
}

ReturnValue_t DataLinkLayer::frameCheckCRC() {
	uint16_t checkValue = CRC::crc16ccitt(this->currentFrame.getFullFrame(),
			this->currentFrame.getFullSize());
	if (checkValue == 0) {
		return RETURN_OK;
	} else {
		return CRC_FAILED;
	}

}

ReturnValue_t DataLinkLayer::allFramesReception() {
	ReturnValue_t status = this->frameDelimitingAndFillRemoval();
	if (status != RETURN_OK) {
		return status;
	}
	return this->frameValidationCheck();
}

ReturnValue_t DataLinkLayer::masterChannelDemultiplexing() {
	//Nothing to do at present. Ideally, there would be a map of MCID's identifying which MC to use.
	return virtualChannelDemultiplexing();
}

ReturnValue_t DataLinkLayer::virtualChannelDemultiplexing() {
	uint8_t vcId = currentFrame.getVirtualChannelId();
	virtualChannelIterator iter = virtualChannels.find(vcId);
	if (iter == virtualChannels.end()) {
		//Do not report because passive board will get this error all the time.
		return RETURN_OK;
	} else {
		return (iter->second)->frameAcceptanceAndReportingMechanism(&currentFrame, clcw);
	}
}

ReturnValue_t DataLinkLayer::processFrame(uint16_t length) {
	receivedDataLength = length;
	ReturnValue_t status = allFramesReception();
	if (status != RETURN_OK) {
		sif::error << "DataLinkLayer::processFrame: frame reception failed. "
		         "Error code: " << std::hex << status << std::dec << std::endl;
//		currentFrame.print();
		return status;
	} else {
		return masterChannelDemultiplexing();
	}
}

ReturnValue_t DataLinkLayer::addVirtualChannel(uint8_t virtualChannelId,
		VirtualChannelReceptionIF* object) {
	std::pair<virtualChannelIterator, bool> returnValue = virtualChannels.insert(
			std::pair<uint8_t, VirtualChannelReceptionIF*>(virtualChannelId, object));
	if (returnValue.second == true) {
		return RETURN_OK;
	} else {
		return RETURN_FAILED;
	}
}

ReturnValue_t DataLinkLayer::initialize() {
	ReturnValue_t returnValue = RETURN_FAILED;
	//Set Virtual Channel ID to first virtual channel instance in this DataLinkLayer instance to avoid faulty information (e.g. 0) in the VCID.
	if ( virtualChannels.begin() != virtualChannels.end() ) {
		clcw->setVirtualChannel( virtualChannels.begin()->second->getChannelId() );
	} else {
		sif::error << "DataLinkLayer::initialize: No VC assigned to this DLL instance! " << std::endl;
		return RETURN_FAILED;
	}

	for (virtualChannelIterator iterator = virtualChannels.begin();
			iterator != virtualChannels.end(); iterator++) {
		returnValue = iterator->second->initialize();
		if (returnValue != RETURN_OK)
			break;
	}
	return returnValue;

}