/* lanalyzer.c
 *
 * $Id: lanalyzer.c,v 1.1 1998/11/12 06:01:22 gram Exp $
 *
 * Wiretap Library
 * Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
 * 
 * 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 2
 * 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 "wtap.h"
#include "lanalyzer.h"

int lanalyzer_open(wtap *wth)
{
	int bytes_read;
	char record_type[2];
	char record_length[2];
	char summary[210];
	guint16 board_type;
	guint16 type, length;

	fseek(wth->fh, 0, SEEK_SET);
	bytes_read = fread(record_type, 1, 2, wth->fh);
	bytes_read += fread(record_length, 1, 2, wth->fh);
	type = pletohs(record_type);
	length = pletohs(record_length); /* make sure to do this for while() loop */

	if (bytes_read != 4) {
		return WTAP_FILE_UNKNOWN;
	}

	if (type != 0x1001 && type != 0x1007) {
		return WTAP_FILE_UNKNOWN;
	}

	/* If we made it this far, then the file is a LANAlyzer file.
	 * Let's get some info from it */
	wth->capture.lanalyzer = g_malloc(sizeof(lanalyzer_t));
	wth->subtype_read = lanalyzer_read;

	/* Read records until we find the start of packets */

	while (1) {
		fseek(wth->fh, length, SEEK_CUR);
		bytes_read = fread(record_type, 1, 2, wth->fh);
		bytes_read += fread(record_length, 1, 2, wth->fh);
		if (bytes_read != 4) {
			return WTAP_FILE_UNKNOWN;
		}

		type = pletohs(record_type);
		length = pletohs(record_length);

/*		g_message("Record 0x%04X Length %d", type, length);*/
		switch (type) {
			/* Trace Summary Record */
			case 0x1002:
				fread(summary, 1, 210, wth->fh);
				length = 0; /* to fake the next iteration of while() */
				board_type = pletohs(&summary[188]);
				switch (board_type) {
					case 226:
						wth->encapsulation = WTAP_ENCAP_ETHERNET;
						break;
					case 227:
						wth->encapsulation = WTAP_ENCAP_TR;
						break;
					default:
						wth->encapsulation = WTAP_ENCAP_NONE;
				}
				break;

			/* Trace Packet Data Record */
			case 0x1005:
				wth->capture.lanalyzer->pkt_len = length - 32;
				return WTAP_FILE_LANALYZER;

			default:
		/*		printf("Record 0x%04X Length %d\n", type, length);*/
		}
	} 

	/* never gets here */
	return WTAP_FILE_LANALYZER;
}

/* Read the next packet */
int lanalyzer_read(wtap *wth)
{
	int packet_size = wth->capture.lanalyzer->pkt_len;
	int bytes_read;
	char record_type[2];
	char record_length[2];
	guint16 type, length;
	gchar descriptor[32];

	/* If this is the very first packet, then the fh cursor will already
	 * be at the start of the packet data instead of at the start of the Trace
	 * Packet Data Record. Check for this */
	if (!packet_size) {

		/* Increment fh cursor to next record */
		bytes_read = fread(record_type, 1, 2, wth->fh);
		bytes_read += fread(record_length, 1, 2, wth->fh);
		if (bytes_read != 4) {
			return 0;
		}

		type = pletohs(record_type);
		length = pletohs(record_length);

		if (type != 0x1005) {
			return 0;
		}
		else {
			packet_size = length - 32;
		}
	}
	else {
		wth->capture.lanalyzer->pkt_len = 0;
	}	

	/* Read the descriptor data */
	bytes_read = fread(descriptor, 1, 32, wth->fh);
	if (bytes_read != 32) {
		g_error("lanalyzer_read: not enough descriptor data (%d bytes)",
				bytes_read);
		return 0;
	}

	buffer_assure_space(&wth->frame_buffer, packet_size);
	bytes_read = fread(buffer_start_ptr(&wth->frame_buffer), 1,
		packet_size, wth->fh);

	if (bytes_read != packet_size) {
		g_error("lanalyzer_read: fread for data: %d bytes out of %d read",
			bytes_read, packet_size);
		return 0;
	}

	wth->phdr.ts.tv_sec = 0;
	wth->phdr.ts.tv_usec = 0;
	wth->phdr.caplen = packet_size;
	wth->phdr.len = packet_size;


	return 1;
}