70 lines
1.7 KiB
C
70 lines
1.7 KiB
C
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/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* hdlc.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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* Necessary because some ISDN devices don't have HDLC
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* controllers.
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*
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* Copyright (C)
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* 2009 Karsten Keil <keil@b1-systems.de>
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* 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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#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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u16 crc;
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u8 cbin;
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u8 shift_reg;
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u8 ffvalue;
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/* set if transferring data */
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u32 data_received:1;
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/* set if D channel (send idle instead of flags) */
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u32 dchannel:1;
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/* set if 56K adaptation */
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u32 do_adapt56:1;
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/* set if in closing phase (need to send CRC + flag) */
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u32 do_closing:1;
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/* set if data is bitreverse */
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u32 do_bitreverse:1;
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};
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/* Feature Flags */
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#define HDLC_56KBIT 0x01
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#define HDLC_DCHANNEL 0x02
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#define HDLC_BITREVERSE 0x04
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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 void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, u32 features);
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extern int isdnhdlc_decode(struct isdnhdlc_vars *hdlc, const u8 *src,
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int slen, int *count, u8 *dst, int dsize);
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extern void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, u32 features);
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extern int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src,
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u16 slen, int *count, u8 *dst, int dsize);
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#endif /* __ISDNHDLC_H__ */
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