1/*
2 * isdnhdlc.h  --  General purpose ISDN HDLC decoder.
3 *
4 * Implementation of a HDLC decoder/encoder in software.
5 * Neccessary because some ISDN devices don't have HDLC
6 * controllers. Also included: a bit reversal table.
7 *
8 *Copyright (C) 2002    Wolfgang M�es      <wolfgang@iksw-muees.de>
9 *		2001 	Frode Isaksen      <fisaksen@bewan.com>
10 *              2001 	Kai Germaschewski  <kai.germaschewski@gmx.de>
11 *
12 *      This program is free software; you can redistribute it and/or modify
13 *      it under the terms of the GNU General Public License as published by
14 *      the Free Software Foundation; either version 2 of the License, or
15 *      (at your option) any later version.
16 *
17 *      This program is distributed in the hope that it will be useful,
18 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
19 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20 *      GNU General Public License for more details.
21 *
22 *      You should have received a copy of the GNU General Public License
23 *      along with this program; if not, write to the Free Software
24 *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 */
26
27#ifndef __ISDNHDLC_H__
28#define __ISDNHDLC_H__
29
30struct isdnhdlc_vars {
31	int bit_shift;
32	int hdlc_bits1;
33	int data_bits;
34	int ffbit_shift; 	// encoding only
35	int state;
36	int dstpos;
37
38	unsigned short crc;
39
40	unsigned char cbin;
41	unsigned char shift_reg;
42	unsigned char ffvalue;
43
44	unsigned int data_received:1; 	// set if transferring data
45	unsigned int dchannel:1; 	// set if D channel (send idle instead of flags)
46	unsigned int do_adapt56:1; 	// set if 56K adaptation
47	unsigned int do_closing:1; 	// set if in closing phase (need to send CRC + flag
48};
49
50
51/*
52  The return value from isdnhdlc_decode is
53  the frame length, 0 if no complete frame was decoded,
54  or a negative error number
55*/
56#define HDLC_FRAMING_ERROR     1
57#define HDLC_CRC_ERROR         2
58#define HDLC_LENGTH_ERROR      3
59
60extern void isdnhdlc_rcv_init (struct isdnhdlc_vars *hdlc, int do_adapt56);
61
62extern int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, int slen,int *count,
63	                    unsigned char *dst, int dsize);
64
65extern void isdnhdlc_out_init (struct isdnhdlc_vars *hdlc,int is_d_channel,int do_adapt56);
66
67extern int isdnhdlc_encode (struct isdnhdlc_vars *hdlc,const unsigned char *src,unsigned short slen,int *count,
68	                    unsigned char *dst,int dsize);
69
70#endif /* __ISDNHDLC_H__ */
71