wireshark/wiretap/aethra.c

/* aethra.c
 *
 * $Id$
 *
 * Wiretap Library
 * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <errno.h>
#include <string.h>
#include "wtap-int.h"
#include "file_wrappers.h"
#include "buffer.h"
#include "aethra.h"

/* Magic number in Aethra PC108 files. */
static const char aethra_magic[5] = "V0208";

/* Aethra file header (minus magic number). */
struct aethra_hdr {
	guint8  unknown[5415];
};

/* Aethra record header.  Yes, the alignment is weird.
   All multi-byte fields are little-endian. */
struct aethrarec_hdr {
	guint8 rec_size[2];	/* record length, not counting the length itself */
	guint8 unknown1;
	guint8 timestamp[4];	/* milliseconds since start of capture */
	guint8 flags;		/* low-order bit: 0 = N->U, 1 = U->N */
};

/*
 * Flags.
 */
#define AETHRA_U_TO_N		0x01

static gboolean aethra_read(wtap *wth, int *err, gchar **err_info,
    gint64 *data_offset);
static gboolean aethra_seek_read(wtap *wth, gint64 seek_off,
    union wtap_pseudo_header *pseudo_header, guint8 *pd, int length,
    int *err, gchar **err_info);
static gboolean aethra_read_rec_header(FILE_T fh, struct aethrarec_hdr *hdr,
    union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info);
static gboolean aethra_read_rec_data(FILE_T fh, guint8 *pd, int length,
    int *err, gchar **err_info);

int aethra_open(wtap *wth, int *err, gchar **err_info)
{
	int bytes_read;
	char magic[sizeof aethra_magic];
	struct aethra_hdr hdr;

	/* Read in the string that should be at the start of a "aethra" file */
	errno = WTAP_ERR_CANT_READ;
	bytes_read = file_read(magic, sizeof magic, wth->fh);
	if (bytes_read != sizeof magic) {
		*err = file_error(wth->fh, err_info);
		if (*err != 0)
			return -1;
		return 0;
	}
	wth->data_offset += sizeof magic;

	if (memcmp(magic, aethra_magic, sizeof aethra_magic) != 0) {
		return 0;
	}

	/* Read the rest of the header. */
	errno = WTAP_ERR_CANT_READ;
	bytes_read = file_read(&hdr, sizeof hdr, wth->fh);
	if (bytes_read != sizeof hdr) {
		*err = file_error(wth->fh, err_info);
		if (*err != 0)
			return -1;
		return 0;
	}
	wth->data_offset += sizeof hdr;
	wth->file_type = WTAP_FILE_AETHRA;
	wth->subtype_read = aethra_read;
	wth->subtype_seek_read = aethra_seek_read;

	/*
	 * We've only seen ISDN files, so, for now, we treat all
	 * files as ISDN.
	 */
	wth->file_encap = WTAP_ENCAP_ISDN;
	wth->snapshot_length = 0;	/* not available in header */
	wth->tsprecision = WTAP_FILE_TSPREC_MSEC;
	return 1;
}

/* Read the next packet */
static gboolean aethra_read(wtap *wth, int *err, gchar **err_info,
    gint64 *data_offset)
{
	struct aethrarec_hdr hdr;
	guint32	rec_size;
	guint32	packet_size;
	guint32	msecs;

	*data_offset = wth->data_offset;

	/* Read record header. */
	if (!aethra_read_rec_header(wth->fh, &hdr, &wth->pseudo_header, err,
	    err_info))
		return FALSE;

	rec_size = pletohs(hdr.rec_size);
	if (rec_size < (sizeof hdr - sizeof hdr.rec_size)) {
		/* The record is shorter than a record header. */
		*err = WTAP_ERR_BAD_RECORD;
		*err_info = g_strdup_printf("aethra: File has %u-byte record, less than minimum of %u",
		    rec_size, (unsigned int)(sizeof hdr - sizeof hdr.rec_size));
		return FALSE;
	}

	wth->data_offset += sizeof hdr;

	packet_size = rec_size - (sizeof hdr - sizeof hdr.rec_size);
	if (packet_size != 0) {
		buffer_assure_space(wth->frame_buffer, packet_size);
		if (!aethra_read_rec_data(wth->fh, buffer_start_ptr(wth->frame_buffer),
		    packet_size, err, err_info))
			return FALSE;	/* Read error */
		wth->data_offset += packet_size;
	}

	/*
	 * XXX - need to find start time in file header.
	 */
	msecs = pletohl(hdr.timestamp);
	wth->phdr.ts.secs = msecs / 1000;
	wth->phdr.ts.nsecs = (msecs % 1000) * 1000000;
	wth->phdr.caplen = packet_size;
	wth->phdr.len = packet_size;

	return TRUE;
}

static gboolean
aethra_seek_read(wtap *wth, gint64 seek_off,
    union wtap_pseudo_header *pseudo_header, guint8 *pd, int length,
    int *err, gchar **err_info)
{
	struct aethrarec_hdr hdr;

	if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
		return FALSE;

	if (!aethra_read_rec_header(wth->random_fh, &hdr, pseudo_header, err, err_info))
		return FALSE;

	/*
	 * Read the packet data.
	 */
	if (!aethra_read_rec_data(wth->random_fh, pd, length, err, err_info))
		return FALSE;	/* failed */

	return TRUE;
}

static gboolean
aethra_read_rec_header(FILE_T fh, struct aethrarec_hdr *hdr,
    union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info)
{
	int	bytes_read;

	/* Read record header. */
	errno = WTAP_ERR_CANT_READ;
	bytes_read = file_read(hdr, sizeof hdr, fh);
	if (bytes_read != sizeof *hdr) {
		*err = file_error(fh, err_info);
		if (*err == 0 && bytes_read != 0)
			*err = WTAP_ERR_SHORT_READ;
		return FALSE;
	}

	pseudo_header->isdn.uton = hdr->flags & AETHRA_U_TO_N;
	pseudo_header->isdn.channel = 0;	/* XXX - D channel */

	return TRUE;
}

static gboolean
aethra_read_rec_data(FILE_T fh, guint8 *pd, int length, int *err,
    gchar **err_info)
{
	int	bytes_read;

	errno = WTAP_ERR_CANT_READ;
	bytes_read = file_read(pd, length, fh);

	if (bytes_read != length) {
		*err = file_error(fh, err_info);
		if (*err == 0)
			*err = WTAP_ERR_SHORT_READ;
		return FALSE;
	}
	return TRUE;
}