1 /* 2 * isdnhdlc.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. Also included: a bit reversal table. 7 * 8 *Copyright (C) 2002 Wolfgang M�es <wolfgang@iksw-muees.de> 9 * 2001 Frode Isaksen <fisaksen@bewan.com> 10 * 2001 Kai Germaschewski <kai.germaschewski@gmx.de> 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License as published by 14 * the Free Software Foundation; either version 2 of the License, or 15 * (at your option) any later version. 16 * 17 * This program is distributed in the hope that it will be useful, 18 * but WITHOUT ANY WARRANTY; without even the implied warranty of 19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 20 * GNU General Public License for more details. 21 * 22 * You should have received a copy of the GNU General Public License 23 * along with this program; if not, write to the Free Software 24 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 25 */ 26 27 #ifndef __ISDNHDLC_H__ 28 #define __ISDNHDLC_H__ 29 30 struct isdnhdlc_vars { 31 int bit_shift; 32 int hdlc_bits1; 33 int data_bits; 34 int ffbit_shift; // encoding only 35 int state; 36 int dstpos; 37 38 unsigned short crc; 39 40 unsigned char cbin; 41 unsigned char shift_reg; 42 unsigned char ffvalue; 43 44 int data_received:1; // set if transferring data 45 int dchannel:1; // set if D channel (send idle instead of flags) 46 int do_adapt56:1; // set if 56K adaptation 47 int do_closing:1; // set if in closing phase (need to send CRC + flag 48 }; 49 50 51 /* 52 The return value from isdnhdlc_decode is 53 the frame length, 0 if no complete frame was decoded, 54 or a negative error number 55 */ 56 #define HDLC_FRAMING_ERROR 1 57 #define HDLC_CRC_ERROR 2 58 #define HDLC_LENGTH_ERROR 3 59 60 extern const unsigned char isdnhdlc_bit_rev_tab[256]; 61 62 extern void isdnhdlc_rcv_init (struct isdnhdlc_vars *hdlc, int do_adapt56); 63 64 extern int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, int slen,int *count, 65 unsigned char *dst, int dsize); 66 67 extern void isdnhdlc_out_init (struct isdnhdlc_vars *hdlc,int is_d_channel,int do_adapt56); 68 69 extern int isdnhdlc_encode (struct isdnhdlc_vars *hdlc,const unsigned char *src,unsigned short slen,int *count, 70 unsigned char *dst,int dsize); 71 72 #endif /* __ISDNHDLC_H__ */ 73