| | 1 | /* |
| | 2 | * hdlc.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. |
| | 7 | * |
| | 8 | * Copyright (C) |
| | 9 | * 2009 Karsten Keil <[email protected]> |
| | 10 | * 2002 Wolfgang Mües <[email protected]> |
| | 11 | * 2001 Frode Isaksen <[email protected]> |
| | 12 | * 2001 Kai Germaschewski <[email protected]> |
| | 13 | * |
| | 14 | * This program is free software; you can redistribute it and/or modify |
| | 15 | * it under the terms of the GNU General Public License as published by |
| | 16 | * the Free Software Foundation; either version 2 of the License, or |
| | 17 | * (at your option) any later version. |
| | 18 | * |
| | 19 | * This program is distributed in the hope that it will be useful, |
| | 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| | 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| | 22 | * GNU General Public License for more details. |
| | 23 | * |
| | 24 | * You should have received a copy of the GNU General Public License |
| | 25 | * along with this program; if not, write to the Free Software |
| | 26 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| | 27 | */ |
| | 28 | |
| | 29 | #ifndef __ISDNHDLC_H__ |
| | 30 | #define __ISDNHDLC_H__ |
| | 31 | |
| | 32 | struct isdnhdlc_vars { |
| | 33 | int bit_shift; |
| | 34 | int hdlc_bits1; |
| | 35 | int data_bits; |
| | 36 | int ffbit_shift; /* encoding only */ |
| | 37 | int state; |
| | 38 | int dstpos; |
| | 39 | |
| | 40 | u16 crc; |
| | 41 | |
| | 42 | u8 cbin; |
| | 43 | u8 shift_reg; |
| | 44 | u8 ffvalue; |
| | 45 | |
| | 46 | /* set if transferring data */ |
| | 47 | u32 data_received:1; |
| | 48 | /* set if D channel (send idle instead of flags) */ |
| | 49 | u32 dchannel:1; |
| | 50 | /* set if 56K adaptation */ |
| | 51 | u32 do_adapt56:1; |
| | 52 | /* set if in closing phase (need to send CRC + flag) */ |
| | 53 | u32 do_closing:1; |
| | 54 | /* set if data is bitreverse */ |
| | 55 | u32 do_bitreverse:1; |
| | 56 | }; |
| | 57 | |
| | 58 | /* Feature Flags */ |
| | 59 | #define HDLC_56KBIT 0x01 |
| | 60 | #define HDLC_DCHANNEL 0x02 |
| | 61 | #define HDLC_BITREVERSE 0x04 |
| | 62 | |
| | 63 | /* |
| | 64 | The return value from isdnhdlc_decode is |
| | 65 | the frame length, 0 if no complete frame was decoded, |
| | 66 | or a negative error number |
| | 67 | */ |
| | 68 | #define HDLC_FRAMING_ERROR 1 |
| | 69 | #define HDLC_CRC_ERROR 2 |
| | 70 | #define HDLC_LENGTH_ERROR 3 |
| | 71 | |
| | 72 | extern void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, u32 features); |
| | 73 | |
| | 74 | extern int isdnhdlc_decode(struct isdnhdlc_vars *hdlc, const u8 *src, |
| | 75 | int slen, int *count, u8 *dst, int dsize); |
| | 76 | |
| | 77 | extern void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, u32 features); |
| | 78 | |
| | 79 | extern int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src, |
| | 80 | u16 slen, int *count, u8 *dst, int dsize); |
| | 81 | |
| | 82 | #endif /* __ISDNHDLC_H__ */ |
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