73 lines
2.4 KiB
C
73 lines
2.4 KiB
C
/*
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* isdnhdlc.h -- General purpose ISDN HDLC decoder.
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*
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* Implementation of a HDLC decoder/encoder in software.
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* Neccessary because some ISDN devices don't have HDLC
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* controllers. Also included: a bit reversal table.
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*
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*Copyright (C) 2002 Wolfgang Mües <wolfgang@iksw-muees.de>
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* 2001 Frode Isaksen <fisaksen@bewan.com>
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* 2001 Kai Germaschewski <kai.germaschewski@gmx.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef __ISDNHDLC_H__
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#define __ISDNHDLC_H__
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struct isdnhdlc_vars {
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int bit_shift;
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int hdlc_bits1;
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int data_bits;
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int ffbit_shift; // encoding only
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int state;
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int dstpos;
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unsigned short crc;
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unsigned char cbin;
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unsigned char shift_reg;
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unsigned char ffvalue;
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int data_received:1; // set if transferring data
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int dchannel:1; // set if D channel (send idle instead of flags)
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int do_adapt56:1; // set if 56K adaptation
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int do_closing:1; // set if in closing phase (need to send CRC + flag
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};
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/*
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The return value from isdnhdlc_decode is
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the frame length, 0 if no complete frame was decoded,
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or a negative error number
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*/
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#define HDLC_FRAMING_ERROR 1
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#define HDLC_CRC_ERROR 2
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#define HDLC_LENGTH_ERROR 3
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extern const unsigned char isdnhdlc_bit_rev_tab[256];
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extern void isdnhdlc_rcv_init (struct isdnhdlc_vars *hdlc, int do_adapt56);
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extern int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, int slen,int *count,
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unsigned char *dst, int dsize);
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extern void isdnhdlc_out_init (struct isdnhdlc_vars *hdlc,int is_d_channel,int do_adapt56);
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extern int isdnhdlc_encode (struct isdnhdlc_vars *hdlc,const unsigned char *src,unsigned short slen,int *count,
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unsigned char *dst,int dsize);
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#endif /* __ISDNHDLC_H__ */
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