Steven Blair / rapid61850example

The goal of this software is to automatically generate C/C++ code which reads and writes GOOSE and Sampled Value packets. Any valid IEC 61850 Substation Configuration Description (SCD) file, describing GOOSE and/or SV communications, can be used as the input. The output code is lightweight and platform-independent, so it can run on a variety of devices, including low-cost microcontrollers. It\'s ideal for rapid-prototyping new protection and control systems that require communications. This mbed project is a simple example of this functionality. Other code: https://github.com/stevenblair/rapid61850 Project homepage: http://personal.strath.ac.uk/steven.m.blair/

svDecodePacket.c

Committer:
sblair
Date:
2011-10-07
Revision:
0:230c10b228ea
Child:
1:9399d44c2b1a

File content as of revision 0:230c10b228ea:

#include "svDecodeBasic.h"
#include "ied.h"
#include "svDecode.h"
#include "svPacketData.h"
#include "decodePacket.h"
#include <stddef.h>


void svDecodeASDU(unsigned char *buf, int len, int noASDU) {
	unsigned char tag;	// assumes only one byte is used
	int lengthFieldSize;
	int lengthValue;
	int offsetForNonSequence;
	unsigned char *svID = NULL;
	int svIDLength = 0;

	int i = 0;
	for (i = 0; i < len;) {
		tag = (unsigned char) buf[i];
		lengthFieldSize = getLengthFieldSize((unsigned char) buf[i + 1]);
		lengthValue = decodeLength((unsigned char *) &buf[i + 1]);
		offsetForNonSequence = 1 + lengthFieldSize + lengthValue;

		//printf("\ttag: %x, noASDU: %u, lengthFieldSize: %i, lengthValue: %i, offset: %i\n", tag, noASDU, lengthFieldSize, lengthValue, offsetForNonSequence);

		switch (tag) {
		case 0x80:
			svID = &buf[i + 1 + lengthFieldSize];
			svIDLength = lengthValue;
			break;
		case 0x81:

			break;
		case 0x82:
			// TODO: may be useful to store smpCnt value
			break;
		case 0x83:

			break;
		case 0x84:

			break;
		case 0x85:

			break;
		case 0x86:

			break;
		case 0x87:
			if (svID != NULL) {
				svDecodeDataset(&buf[i + 1 + lengthFieldSize], lengthValue, noASDU, svID, svIDLength);
			}
			break;
		default:
			break;
		}

		i += offsetForNonSequence;
	}
}

void svDecodeAPDU(unsigned char *buf, int len) {
	unsigned char tag = (unsigned char) buf[0];	// assumes only one byte is used
	int lengthFieldSize = getLengthFieldSize((unsigned char) buf[1]);
	int lengthValue = decodeLength((unsigned char *) &buf[1]);
	int offsetForSequence = 1 + lengthFieldSize;
	int offsetForNonSequence = 1 + lengthFieldSize + lengthValue;
	//static unsigned int noASDU = 0;
	static unsigned int ASDU = 0;

	//printf("tag: %x, noASDU: %u, lengthFieldSize: %i, lengthValue: %i, offset: %i\n", tag, noASDU, lengthFieldSize, lengthValue, offsetForNonSequence);

	switch (tag) {
	case 0x60:
		svDecodeAPDU(&buf[offsetForSequence], lengthValue);
		break;
	case 0x80:
		//noASDU = (unsigned int) buf[1 + lengthFieldSize];	// assuming noASDU is < 126
		ASDU = 0;
		svDecodeAPDU(&buf[offsetForNonSequence], len - offsetForNonSequence);
		break;
	case 0xA2:
		svDecodeAPDU(&buf[offsetForSequence], lengthValue);
		break;
	case 0x30:
		svDecodeASDU(&buf[offsetForSequence], lengthValue, ASDU++);

		svDecodeAPDU(&buf[offsetForNonSequence], len - offsetForNonSequence);
		break;
	default:
		break;
	}
}

void svDecode(unsigned char *buf, int len) {
	unsigned short APDULength = ((buf[21] << 8) | buf[22]) - 8;	// must use length in PDU because total bytes (len) may contain CRC

	svDecodeAPDU(&buf[26], APDULength);	// cuts out frame header (fixed size of 26 bytes before start of APDU)
}