gseDecodePacket.c

00001 /**
00002  * Rapid-prototyping protection schemes with IEC 61850
00003  *
00004  * Copyright (c) 2011 Steven Blair
00005  * 
00006  * This program is free software; you can redistribute it and/or
00007  * modify it under the terms of the GNU General Public License
00008  * as published by the Free Software Foundation; either version 2
00009  * of the License, or (at your option) any later version.
00010 
00011  * This program is distributed in the hope that it will be useful,
00012  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014  * GNU General Public License for more details.
00015 
00016  * You should have received a copy of the GNU General Public License
00017  * along with this program; if not, write to the Free Software
00018  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
00019  */
00020 
00021 #include "gseDecodeBasic.h"
00022 #include "ied.h"
00023 #include "gseDecode.h"
00024 #include "gsePacketData.h"
00025 #include "decodePacket.h"
00026 #include <stddef.h>
00027 
00028 
00029 unsigned char    datasetName[65] = {0};        // maximum length of 65 bytes
00030 CTYPE_INT16U    datasetNameLength = 0;
00031 
00032 
00033 void gseDecodePDU(unsigned char *buf) {
00034     unsigned char    tag = (unsigned char) buf[0];    // assumes only one byte is used
00035     CTYPE_INT16U    lengthFieldSize = getLengthFieldSize((unsigned char) buf[1]);
00036     CTYPE_INT16U    lengthValue = decodeLength((unsigned char *) &buf[1]);
00037     CTYPE_INT16U    offsetForSequence = 1 + lengthFieldSize;
00038     CTYPE_INT16U    offsetForNonSequence = 1 + lengthFieldSize + lengthValue;
00039 
00040     //printf("tag: %x, lengthFieldSize: %i, lengthValue: %i, offset: %i\n", tag, lengthFieldSize, lengthValue, offsetForNonSequence);
00041 
00042     switch (tag) {
00043     case 0x61:
00044         gseDecodePDU(&buf[offsetForSequence]);
00045         break;
00046     case 0x82:
00047         // save dataset name
00048         memcpy(datasetName, &buf[offsetForSequence], lengthValue);
00049         datasetNameLength = lengthValue;
00050         //printf("%s, %d\n", datasetName, datasetNameLength);
00051         //fflush(stdout);
00052 
00053         gseDecodePDU(&buf[offsetForNonSequence]);
00054         break;
00055     case 0xAB:
00056         gseDecodeDataset(&buf[offsetForSequence], lengthValue, datasetName, datasetNameLength);
00057         return;
00058         //break;
00059     default:
00060         gseDecodePDU(&buf[offsetForNonSequence]);
00061         break;
00062     }
00063 }
00064 
00065 void gseDecode(unsigned char *buf, int len) {
00066     gseDecodePDU(&buf[26]);    // cuts out frame header (fixed size of 26 bytes before start of APDU)
00067 }