diff options
Diffstat (limited to 'include/osmocom')
| -rw-r--r-- | include/osmocom/core/isdnhdlc.h | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/include/osmocom/core/isdnhdlc.h b/include/osmocom/core/isdnhdlc.h new file mode 100644 index 00000000..96521370 --- /dev/null +++ b/include/osmocom/core/isdnhdlc.h @@ -0,0 +1,82 @@ +/* + * hdlc.h -- General purpose ISDN HDLC decoder. + * + * Implementation of a HDLC decoder/encoder in software. + * Necessary because some ISDN devices don't have HDLC + * controllers. + * + * Copyright (C) + * 2009 Karsten Keil <keil@b1-systems.de> + * 2002 Wolfgang Mües <wolfgang@iksw-muees.de> + * 2001 Frode Isaksen <fisaksen@bewan.com> + * 2001 Kai Germaschewski <kai.germaschewski@gmx.de> + * + * 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., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#ifndef __ISDNHDLC_H__ +#define __ISDNHDLC_H__ + +struct isdnhdlc_vars { + int bit_shift; + int hdlc_bits1; + int data_bits; + int ffbit_shift; /* encoding only */ + int state; + int dstpos; + + u16 crc; + + u8 cbin; + u8 shift_reg; + u8 ffvalue; + + /* set if transferring data */ + u32 data_received:1; + /* set if D channel (send idle instead of flags) */ + u32 dchannel:1; + /* set if 56K adaptation */ + u32 do_adapt56:1; + /* set if in closing phase (need to send CRC + flag) */ + u32 do_closing:1; + /* set if data is bitreverse */ + u32 do_bitreverse:1; +}; + +/* Feature Flags */ +#define HDLC_56KBIT 0x01 +#define HDLC_DCHANNEL 0x02 +#define HDLC_BITREVERSE 0x04 + +/* + The return value from isdnhdlc_decode is + the frame length, 0 if no complete frame was decoded, + or a negative error number +*/ +#define HDLC_FRAMING_ERROR 1 +#define HDLC_CRC_ERROR 2 +#define HDLC_LENGTH_ERROR 3 + +extern void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, u32 features); + +extern int isdnhdlc_decode(struct isdnhdlc_vars *hdlc, const u8 *src, + int slen, int *count, u8 *dst, int dsize); + +extern void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, u32 features); + +extern int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src, + u16 slen, int *count, u8 *dst, int dsize); + +#endif /* __ISDNHDLC_H__ */ |