317 lines
8.6 KiB
C
317 lines
8.6 KiB
C
/* eyesdn.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 "wtap-int.h"
|
|
#include "buffer.h"
|
|
#include "eyesdn.h"
|
|
#include "file_wrappers.h"
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <errno.h>
|
|
|
|
/* This module reads the output of the EyeSDN USB S0/E1 ISDN probes
|
|
* They store HDLC frames of D and B channels in a binary format
|
|
* The fileformat is
|
|
*
|
|
* 1-6 Byte: EyeSDN - Magic
|
|
* 7-n Byte: Frames
|
|
*
|
|
* Each Frame starts with the 0xff Flag byte
|
|
* - Bytes 0-2: timestamp (long usec in network byte order)
|
|
* - Bytes 3-7: timestamp (40bits sec since 1970 in network byte order)
|
|
* - Byte 8: channel (0 for D channel, 1-30 for B1-B30)
|
|
* - Byte 9: Sender (0 NT, 1 TE)
|
|
* - Byte 10-11: frame size in bytes
|
|
* - Byte 12-n: Frame Payload
|
|
*
|
|
* All multibyte values are represented in network byte order
|
|
* The frame is terminated with a flag character (0xff)
|
|
* bytes 0xff within a frame are escaped using the 0xfe escape character
|
|
* the byte following the escape character is decremented by two:
|
|
* so 0xfe 0xfd is actually a 0xff
|
|
* Characters that need to be escaped are 0xff and 0xfe
|
|
*/
|
|
|
|
|
|
static int esc_read(guint8 *buf, int len, FILE_T fh)
|
|
{
|
|
int i;
|
|
int value;
|
|
|
|
for(i=0; i<len; i++) {
|
|
value=file_getc(fh);
|
|
if(value==-1)
|
|
return -2; /* EOF or error */
|
|
if(value==0xff)
|
|
return -1; /* error !!, read into next frame */
|
|
if(value==0xfe) {
|
|
/* we need to escape */
|
|
value=file_getc(fh);
|
|
if(value==-1)
|
|
return -2;
|
|
value+=2;
|
|
}
|
|
buf[i]=value;
|
|
}
|
|
return i;
|
|
}
|
|
|
|
/* Magic text to check for eyesdn-ness of file */
|
|
static const unsigned char eyesdn_hdr_magic[] =
|
|
{ 'E', 'y', 'e', 'S', 'D', 'N'};
|
|
#define EYESDN_HDR_MAGIC_SIZE (sizeof(eyesdn_hdr_magic) / sizeof(eyesdn_hdr_magic[0]))
|
|
|
|
/* Size of a record header */
|
|
#define EYESDN_HDR_LENGTH 12
|
|
|
|
/*
|
|
* XXX - is this the biggest packet we can get?
|
|
*/
|
|
#define EYESDN_MAX_PACKET_LEN 16384
|
|
|
|
static gboolean eyesdn_read(wtap *wth, int *err, gchar **err_info,
|
|
long *data_offset);
|
|
static gboolean eyesdn_seek_read(wtap *wth, long seek_off,
|
|
union wtap_pseudo_header *pseudo_header, guint8 *pd, int len,
|
|
int *err, gchar **err_info);
|
|
static gboolean parse_eyesdn_packet_data(FILE_T fh, int pkt_len, guint8* buf,
|
|
int *err, gchar **err_info);
|
|
static int parse_eyesdn_rec_hdr(wtap *wth, FILE_T fh,
|
|
union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info);
|
|
|
|
/* Seeks to the beginning of the next packet, and returns the
|
|
byte offset. Returns -1 on failure, and sets "*err" to the error. */
|
|
static long eyesdn_seek_next_packet(wtap *wth, int *err)
|
|
{
|
|
int byte;
|
|
long cur_off;
|
|
|
|
while ((byte = file_getc(wth->fh)) != EOF) {
|
|
if (byte == 0xff) {
|
|
cur_off = file_tell(wth->fh);
|
|
if (cur_off == -1) {
|
|
/* Error. */
|
|
*err = file_error(wth->fh);
|
|
return -1;
|
|
}
|
|
return cur_off;
|
|
}
|
|
}
|
|
if (file_eof(wth->fh)) {
|
|
/* We got an EOF. */
|
|
*err = 0;
|
|
} else {
|
|
/* We (presumably) got an error (there's no equivalent to "ferror()"
|
|
in zlib, alas, so we don't have a wrapper to check for an error). */
|
|
*err = file_error(wth->fh);
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
int eyesdn_open(wtap *wth, int *err, gchar **err_info _U_)
|
|
{
|
|
int bytes_read;
|
|
char magic[EYESDN_HDR_MAGIC_SIZE];
|
|
|
|
/* Look for eyesdn header */
|
|
errno = WTAP_ERR_CANT_READ;
|
|
bytes_read = file_read(&magic, 1, sizeof magic, wth->fh);
|
|
if (bytes_read != sizeof magic) {
|
|
*err = file_error(wth->fh);
|
|
if (*err != 0)
|
|
return -1;
|
|
return 0;
|
|
}
|
|
if (memcmp(magic, eyesdn_hdr_magic, EYESDN_HDR_MAGIC_SIZE) != 0)
|
|
return 0;
|
|
|
|
wth->data_offset = 0;
|
|
wth->file_encap = WTAP_ENCAP_ISDN;
|
|
wth->file_type = WTAP_FILE_EYESDN;
|
|
wth->snapshot_length = 0; /* not known */
|
|
wth->subtype_read = eyesdn_read;
|
|
wth->subtype_seek_read = eyesdn_seek_read;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* Find the next packet and parse it; called from wtap_read(). */
|
|
static gboolean eyesdn_read(wtap *wth, int *err, gchar **err_info,
|
|
long *data_offset)
|
|
{
|
|
long offset;
|
|
guint8 *buf;
|
|
int pkt_len;
|
|
|
|
/* Find the next packet */
|
|
offset = eyesdn_seek_next_packet(wth, err);
|
|
if (offset < 1)
|
|
return FALSE;
|
|
|
|
/* Parse the header */
|
|
pkt_len = parse_eyesdn_rec_hdr(wth, wth->fh, &wth->pseudo_header, err,
|
|
err_info);
|
|
if (pkt_len == -1)
|
|
return FALSE;
|
|
|
|
/* Make sure we have enough room for the packet */
|
|
buffer_assure_space(wth->frame_buffer, EYESDN_MAX_PACKET_LEN);
|
|
buf = buffer_start_ptr(wth->frame_buffer);
|
|
|
|
/* Read the packet data */
|
|
if (!parse_eyesdn_packet_data(wth->fh, pkt_len, buf, err, err_info))
|
|
return FALSE;
|
|
|
|
wth->data_offset = offset;
|
|
*data_offset = offset;
|
|
return TRUE;
|
|
}
|
|
|
|
/* Used to read packets in random-access fashion */
|
|
static gboolean
|
|
eyesdn_seek_read (wtap *wth, long seek_off,
|
|
union wtap_pseudo_header *pseudo_header, guint8 *pd, int len,
|
|
int *err, gchar **err_info)
|
|
{
|
|
int pkt_len;
|
|
|
|
if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
|
|
return FALSE;
|
|
|
|
pkt_len = parse_eyesdn_rec_hdr(NULL, wth->random_fh, pseudo_header,
|
|
err, err_info);
|
|
|
|
if (pkt_len != len) {
|
|
if (pkt_len != -1) {
|
|
*err = WTAP_ERR_BAD_RECORD;
|
|
*err_info = g_strdup_printf("eyesdn: requested length %d doesn't match length %d",
|
|
len, pkt_len);
|
|
}
|
|
return FALSE;
|
|
}
|
|
|
|
return parse_eyesdn_packet_data(wth->random_fh, pkt_len, pd, err,
|
|
err_info);
|
|
}
|
|
|
|
/* Parses a packet record header. */
|
|
static int
|
|
parse_eyesdn_rec_hdr(wtap *wth, FILE_T fh,
|
|
union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info)
|
|
{
|
|
guint8 hdr[EYESDN_HDR_LENGTH];
|
|
unsigned long secs, usecs;
|
|
int pkt_len;
|
|
unsigned int channel, direction;
|
|
|
|
/* Our file pointer should be at the summary information header
|
|
* for a packet. Read in that header and extract the useful
|
|
* information.
|
|
*/
|
|
if (esc_read(hdr, EYESDN_HDR_LENGTH, fh) != EYESDN_HDR_LENGTH) {
|
|
*err = file_error(fh);
|
|
if (*err == 0)
|
|
*err = WTAP_ERR_SHORT_READ;
|
|
return -1;
|
|
}
|
|
|
|
/* extract information from header */
|
|
usecs = ((unsigned long) hdr[0]);
|
|
usecs = (usecs << 8) | ((unsigned long) hdr[1]);
|
|
usecs = (usecs << 8) | ((unsigned long) hdr[2]);
|
|
#ifdef TV64BITS
|
|
secs = ((unsigned long) hdr[3]);
|
|
#else
|
|
secs = 0;
|
|
#endif
|
|
secs = (secs << 8) | ((unsigned long) hdr[4]);
|
|
secs = (secs << 8) | ((unsigned long) hdr[5]);
|
|
secs = (secs << 8) | ((unsigned long) hdr[6]);
|
|
secs = (secs << 8) | ((unsigned long) hdr[7]);
|
|
|
|
channel = hdr[8];
|
|
direction = hdr[9];
|
|
pkt_len = ((unsigned long) hdr[10]);
|
|
pkt_len = (pkt_len << 8) | ((unsigned long) hdr[11]);
|
|
|
|
/* sanity checks */
|
|
if(channel>30) {
|
|
*err = WTAP_ERR_BAD_RECORD;
|
|
*err_info = g_strdup_printf("eyesdn: bad channel number %u",
|
|
channel);
|
|
return -1;
|
|
}
|
|
|
|
if(direction>1) {
|
|
*err = WTAP_ERR_BAD_RECORD;
|
|
*err_info = g_strdup_printf("eyesdn: bad direction value %u",
|
|
direction);
|
|
return -1;
|
|
}
|
|
if(pkt_len > EYESDN_MAX_PACKET_LEN) {
|
|
*err = WTAP_ERR_BAD_RECORD;
|
|
*err_info = g_strdup_printf("eyesdn: File has %u-byte packet, bigger than maximum of %u",
|
|
pkt_len, EYESDN_MAX_PACKET_LEN);
|
|
return -1;
|
|
}
|
|
|
|
if (wth) {
|
|
wth->phdr.ts.secs = secs;
|
|
wth->phdr.ts.nsecs = usecs * 1000;
|
|
wth->phdr.caplen = pkt_len;
|
|
wth->phdr.len = pkt_len;
|
|
}
|
|
pseudo_header->isdn.uton = direction;
|
|
pseudo_header->isdn.channel = channel;
|
|
|
|
return pkt_len;
|
|
}
|
|
|
|
/* read a packet */
|
|
static gboolean
|
|
parse_eyesdn_packet_data(FILE_T fh, int pkt_len, guint8* buf, int *err,
|
|
gchar **err_info)
|
|
{
|
|
int bytes_read;
|
|
|
|
errno = WTAP_ERR_CANT_READ;
|
|
bytes_read = esc_read(buf, pkt_len, fh);
|
|
if (bytes_read != pkt_len) {
|
|
if (bytes_read == -2) {
|
|
*err = file_error(fh);
|
|
if (*err == 0)
|
|
*err = WTAP_ERR_SHORT_READ;
|
|
} else if (bytes_read == -1) {
|
|
*err = WTAP_ERR_BAD_RECORD;
|
|
*err_info = g_strdup("eyesdn: No flag character seen in frame");
|
|
} else
|
|
*err = WTAP_ERR_SHORT_READ;
|
|
return FALSE;
|
|
}
|
|
return TRUE;
|
|
}
|