/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * 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> */ #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__ */