/* *      hdlc.c -- hdlc decoder and AX.25 packet dump * *      Copyright (C) 1996   *          Thomas Sailer (sailer@ife.ee.ethz.ch, hb9jnx@hb9w.che.eu) * *      This program is free software; you can redistribute it and/or modify *      it under the terms of the GNU General Public License as published by *      the Free Software Foundation; either version 2 of the License, or *      (at your option) any later version. * *      This program is distributed in the hope that it will be useful, *      but WITHOUT ANY WARRANTY; without even the implied warranty of *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the *      GNU General Public License for more details. * *      You should have received a copy of the GNU General Public License *      along with this program; if not, write to the Free Software *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. *//* ---------------------------------------------------------------------- */#include "multimon.h"#include <string.h>/* ---------------------------------------------------------------------- *//* * the CRC routines are stolen from WAMPES * by Dieter Deyke */static const unsigned short crc_ccitt_table[] = {        0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,        0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,        0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,        0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,        0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,        0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,        0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,        0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,        0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,        0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,        0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,        0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,        0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,        0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,        0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,        0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,        0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,        0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,        0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,        0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,        0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,        0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,        0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,        0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,        0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,        0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,        0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,        0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,        0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,        0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,        0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,        0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78};/* ---------------------------------------------------------------------- */static inline int check_crc_ccitt(const unsigned char *buf, int cnt){        unsigned int crc = 0xffff;        for (; cnt > 0; cnt--)                crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ *buf++) & 0xff];        return (crc & 0xffff) == 0xf0b8;}/* ---------------------------------------------------------------------- */static void ax25_disp_packet(struct demod_state *s, unsigned char *bp, unsigned int len){        unsigned char v1=1,cmd=0;        unsigned char i,j;        if (!bp || len < 10) 		return;#if 1	if (!check_crc_ccitt(bp, len))		return;#endif	len -= 2;        if (bp[1] & 1) {                /*                 * FlexNet Header Compression                 */                v1 = 0;                cmd = (bp[1] & 2) != 0;                verbprintf(0, "%s: fm ? to ", s->dem_par->name);                i = (bp[2] >> 2) & 0x3f;                if (i) 			verbprintf(0, "%c",i+0x20);                i = ((bp[2] << 4) | ((bp[3] >> 4) & 0xf)) & 0x3f;                if (i) 			verbprintf(0, "%c",i+0x20);                i = ((bp[3] << 2) | ((bp[4] >> 6) & 3)) & 0x3f;                if (i) 			verbprintf(0, "%c",i+0x20);                i = bp[4] & 0x3f;                if (i) 			verbprintf(0, "%c",i+0x20);                i = (bp[5] >> 2) & 0x3f;                if (i) 			verbprintf(0, "%c",i+0x20);                i = ((bp[5] << 4) | ((bp[6] >> 4) & 0xf)) & 0x3f;                if (i) 			verbprintf(0, "%c",i+0x20);                verbprintf(0, "-%u QSO Nr %u", bp[6] & 0xf, (bp[0] << 6) | (bp[1] >> 2));                bp += 7;                len -= 7;        } else {                /*                 * normal header                 */                if (len < 15) 			return;                if ((bp[6] & 0x80) != (bp[13] & 0x80)) {                        v1 = 0;                        cmd = (bp[6] & 0x80);                }                verbprintf(0, "%s: fm ", s->dem_par->name);		for(i = 7; i < 13; i++)                         if ((bp[i] &0xfe) != 0x40)                                 verbprintf(0, "%c",bp[i] >> 1);                verbprintf(0, "-%u to ",(bp[13] >> 1) & 0xf);                for(i = 0; i < 6; i++)                         if ((bp[i] &0xfe) != 0x40)                                 verbprintf(0, "%c",bp[i] >> 1);                verbprintf(0, "-%u",(bp[6] >> 1) & 0xf);                bp += 14;                len -= 14;                if ((!(bp[-1] & 1)) && (len >= 7)) 			verbprintf(0, " via ");                while ((!(bp[-1] & 1)) && (len >= 7)) {                        for(i = 0; i < 6; i++)                                 if ((bp[i] &0xfe) != 0x40)                                         verbprintf(0, "%c",bp[i] >> 1);                        verbprintf(0, "-%u",(bp[6] >> 1) & 0xf);                        bp += 7;                        len -= 7;                        if ((!(bp[-1] & 1)) && (len >= 7))                                 verbprintf(0, ",");                }        }        if(!len)                 return;        i = *bp++;        len--;        j = v1 ? ((i & 0x10) ? '!' : ' ') :                 ((i & 0x10) ? (cmd ? '+' : '-') : (cmd ? '^' : 'v'));        if (!(i & 1)) {                /*                 * Info frame                 */                verbprintf(0, " I%u%u%c",(i >> 5) & 7,(i >> 1) & 7,j);        } else if (i & 2) {                /*                 * U frame                 */                switch (i & (~0x10)) {                case 0x03:                        verbprintf(0, " UI%c",j);                        break;                case 0x2f:                        verbprintf(0, " SABM%c",j);                        break;                case 0x43:                        verbprintf(0, " DISC%c",j);                        break;                case 0x0f:                        verbprintf(0, " DM%c",j);                        break;                case 0x63:                        verbprintf(0, " UA%c",j);                        break;                case 0x87:                        verbprintf(0, " FRMR%c",j);                        break;                default:                        verbprintf(0, " unknown U (0x%x)%c",i & (~0x10),j);                        break;                }        } else {                /*                 * supervisory                 */                switch (i & 0xf) {                case 0x1:                        verbprintf(0, " RR%u%c",(i >> 5) & 7,j);                        break;                case 0x5:                        verbprintf(0, " RNR%u%c",(i >> 5) & 7,j);                        break;                case 0x9:                        verbprintf(0, " REJ%u%c",(i >> 5) & 7,j);                        break;                default:                        verbprintf(0, " unknown S (0x%x)%u%c", i & 0xf,                                (i >> 5) & 7, j);                        break;                }        }        if (!len) {                verbprintf(0, "\n");                return;        }        verbprintf(0, " pid=%02X\n", *bp++);        len--;        j = 0;        while (len) {                i = *bp++;                if ((i >= 32) && (i < 128))                         verbprintf(0, "%c",i);                else if (i == 13) {                        if (j)                                 verbprintf(0, "\n");                        j = 0;                } else                         verbprintf(0, ".");                if (i >= 32)                         j = 1;                len--;        }        if (j)                 verbprintf(0, "\n");}/* ---------------------------------------------------------------------- */void hdlc_init(struct demod_state *s){	memset(&s->l2.hdlc, 0, sizeof(s->l2.hdlc));}/* ---------------------------------------------------------------------- */void hdlc_rxbit(struct demod_state *s, int bit){	s->l2.hdlc.rxbitstream <<= 1;	s->l2.hdlc.rxbitstream |= !!bit;	if ((s->l2.hdlc.rxbitstream & 0xff) == 0x7e) {		if (s->l2.hdlc.rxstate && (s->l2.hdlc.rxptr - s->l2.hdlc.rxbuf) > 2)			ax25_disp_packet(s, s->l2.hdlc.rxbuf, s->l2.hdlc.rxptr - s->l2.hdlc.rxbuf);		s->l2.hdlc.rxstate = 1;		s->l2.hdlc.rxptr = s->l2.hdlc.rxbuf;		s->l2.hdlc.rxbitbuf = 0x80;		return;	}	if ((s->l2.hdlc.rxbitstream & 0x7f) == 0x7f) {		s->l2.hdlc.rxstate = 0;		return;	}	if (!s->l2.hdlc.rxstate)		return;	if ((s->l2.hdlc.rxbitstream & 0x3f) == 0x3e) /* stuffed bit */		return;	if (s->l2.hdlc.rxbitstream & 1)		s->l2.hdlc.rxbitbuf |= 0x100;	if (s->l2.hdlc.rxbitbuf & 1) {		if (s->l2.hdlc.rxptr >= s->l2.hdlc.rxbuf+sizeof(s->l2.hdlc.rxbuf)) {			s->l2.hdlc.rxstate = 0;			verbprintf(1, "Error: packet size too large\n");			return;		}		*s->l2.hdlc.rxptr++ = s->l2.hdlc.rxbitbuf >> 1;		s->l2.hdlc.rxbitbuf = 0x80;		return;	}      	s->l2.hdlc.rxbitbuf >>= 1;}/* ---------------------------------------------------------------------- */