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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 Mües <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 int data_received:1; // set if transferring data
45 int dchannel:1; // set if D channel (send idle instead of flags)
46 int do_adapt56:1; // set if 56K adaptation
47 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 const unsigned char isdnhdlc_bit_rev_tab[256];
61
62extern void isdnhdlc_rcv_init (struct isdnhdlc_vars *hdlc, int do_adapt56);
63
64extern int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, int slen,int *count,
65 unsigned char *dst, int dsize);
66
67extern void isdnhdlc_out_init (struct isdnhdlc_vars *hdlc,int is_d_channel,int do_adapt56);
68
69extern int isdnhdlc_encode (struct isdnhdlc_vars *hdlc,const unsigned char *src,unsigned short slen,int *count,
70 unsigned char *dst,int dsize);
71
72#endif /* __ISDNHDLC_H__ */