/*
* Copyright (c) 2008, Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
package org.contikios.cooja.mspmote.interfaces;
import org.contikios.cooja.ConvertedRadioPacket;
import org.contikios.cooja.RadioPacket;
import se.sics.mspsim.util.CCITT_CRC;
/**
* Converts radio packets between nullmac/CC24240/Sky and COOJA.
* Handles radio driver specifics such as length header and CRC footer.
*
* @author Fredrik Osterlind
*/
public class CC2420RadioPacketConverter {
public static final boolean WITH_PREAMBLE = true;
public static final boolean WITH_SYNCH = true;
public static final boolean WITH_XMAC = false; /* XXX No longer supported. Cross-level requires NULLMAC */
public static final boolean WITH_CHECKSUM = false; /* Contiki checksum. Not CC2420's built-in. */
public static final boolean WITH_TIMESTAMP = false; /* Contiki timestamp */
public static final boolean WITH_FOOTER = true; /* CC2420's checksum */
public static byte[] fromCoojaToCC2420(RadioPacket packet) {
byte cc2420Data[] = new byte[6+127];
int pos = 0;
byte packetData[] = packet.getPacketData();
byte len; /* total packet minus preamble(4), synch(1) and length(1) */
CCITT_CRC cc2420CRC = new CCITT_CRC();
short contikiCRC = 0;
/* 4 bytes preamble */
if (WITH_PREAMBLE) {
cc2420Data[pos++] = 0;
cc2420Data[pos++] = 0;
cc2420Data[pos++] = 0;
cc2420Data[pos++] = 0;
}
/* 1 byte synch */
if (WITH_SYNCH) {
cc2420Data[pos++] = 0x7A;
}
/* 1 byte length */
len = (byte) packetData.length;
if (WITH_XMAC) {
len += 6;
}
if (WITH_CHECKSUM) {
len += 2;
}
if (WITH_TIMESTAMP) {
len += 3;
}
if (WITH_FOOTER) {
len += 2;
}
cc2420Data[pos++] = len;
cc2420CRC.setCRC(0);
/* 4 byte X-MAC: not implemented */
if (WITH_XMAC) {
cc2420Data[pos++] = 1; /* TYPE_DATA */
cc2420CRC.addBitrev(1);
contikiCRC = CRCCoder.crc16Add((byte)0, contikiCRC);
cc2420Data[pos++] = 0;
cc2420CRC.addBitrev(0);
contikiCRC = CRCCoder.crc16Add((byte)0, contikiCRC);
cc2420Data[pos++] = 0; /* XXX sender: 0.0 */
cc2420CRC.addBitrev(0);
contikiCRC = CRCCoder.crc16Add((byte)0, contikiCRC);
cc2420Data[pos++] = 0;
cc2420CRC.addBitrev(0);
contikiCRC = CRCCoder.crc16Add((byte)0, contikiCRC);
cc2420Data[pos++] = 0; /* XXX receiver: 0.0 */
cc2420CRC.addBitrev(0);
contikiCRC = CRCCoder.crc16Add((byte)0, contikiCRC);
cc2420Data[pos++] = 0;
cc2420CRC.addBitrev(0);
contikiCRC = CRCCoder.crc16Add((byte)0, contikiCRC);
}
/* Payload */
for (byte b : packetData) {
contikiCRC = CRCCoder.crc16Add(b, contikiCRC);
cc2420CRC.addBitrev(b & 0xFF);
}
System.arraycopy(packetData, 0, cc2420Data, pos, packetData.length);
pos += packetData.length;
/* 2 bytes checksum */
if (WITH_CHECKSUM) {
cc2420Data[pos++] = (byte) (contikiCRC & 0xff);
cc2420CRC.addBitrev(contikiCRC & 0xFF);
cc2420Data[pos++] = (byte) ((contikiCRC >> 8) & 0xff);
cc2420CRC.addBitrev((contikiCRC >> 8) & 0xFF);
}
/* (TODO) 3 bytes timestamp */
if (WITH_TIMESTAMP) {
cc2420Data[pos++] = 0;
cc2420CRC.addBitrev(0);
cc2420Data[pos++] = 0;
cc2420CRC.addBitrev(0);
cc2420Data[pos++] = 0;
cc2420CRC.addBitrev(0);
}
/* 2 bytes footer: CC2420's CRC */
if (WITH_FOOTER) {
cc2420Data[pos++] = (byte) cc2420CRC.getCRCHi();
cc2420Data[pos++] = (byte) cc2420CRC.getCRCLow();
}
byte cc2420DataStripped[] = new byte[pos];
System.arraycopy(cc2420Data, 0, cc2420DataStripped, 0, pos);
/*logger.info("Data length: " + cc2420DataStripped.length);*/
return cc2420DataStripped;
}
public static ConvertedRadioPacket fromCC2420ToCooja(byte[] data) {
int pos = 0;
int len; /* Payload */
int originalLen;
/* Use some CC2420/MAC specific field such as X-MAC response */
/* (IGNORED) 4 bytes preamble */
if (WITH_PREAMBLE) {
pos += 4;
}
/* (IGNORED) 1 byte synch */
if (WITH_SYNCH) {
pos += 1;
}
/* 1 byte length */
len = data[pos];
originalLen = len;
pos += 1;
/* 4 byte X-MAC: not implemented */
if (WITH_XMAC) {
pos += 6;
len -= 6;
}
/* (IGNORED) 2 bytes checksum */
if (WITH_CHECKSUM) {
len -= 2;
}
/* (IGNORED) 3 bytes timestamp */
if (WITH_TIMESTAMP) {
len -= 3;
}
/* (IGNORED) 2 bytes footer */
if (WITH_FOOTER) {
/* TODO Implement */
len -= 2;
}
/*logger.info("Payload pos: " + pos);
logger.info("Payload length: " + len);*/
byte originalData[] = new byte[originalLen];
System.arraycopy(data, 6 /* skipping preamble+synch+len */, originalData, 0, originalLen);
if (len < 0) {
/*logger.warn("No cross-level conversion available: negative packet length");*/
return new ConvertedRadioPacket(new byte[0], originalData);
}
byte convertedData[] = new byte[len];
System.arraycopy(data, pos, convertedData, 0, len);
return new ConvertedRadioPacket(convertedData, originalData);
}
}