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Diffstat (limited to 'sys/i4b/layer1/i4b_hdlc.h')
| -rw-r--r-- | sys/i4b/layer1/i4b_hdlc.h | 387 |
1 files changed, 387 insertions, 0 deletions
diff --git a/sys/i4b/layer1/i4b_hdlc.h b/sys/i4b/layer1/i4b_hdlc.h new file mode 100644 index 0000000..a34fb03 --- /dev/null +++ b/sys/i4b/layer1/i4b_hdlc.h @@ -0,0 +1,387 @@ +/* + * Copyright (c) 2000 Hans Petter Selasky. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + *--------------------------------------------------------------------------- + * + * i4b_hdlc.h - software-HDLC header file + * -------------------------------------- + * + * $Id: i4b_hdlc.h,v 1.5 2000/08/28 07:41:19 hm Exp $ + * + * $FreeBSD$ + * + * last edit-date: [Wed Jul 19 09:41:13 2000] + * + *---------------------------------------------------------------------------*/ + +#ifndef _I4B_HDLC_H_ +#define _I4B_HDLC_H_ + +/*---------------------------------------------------------------------------* + * HDLC CRC table + * + * Usage: + * crc = (HDLC_FCS_TAB[(u_char)(crc ^ byte of data)] ^ (u_char)(crc >> 8)); + * + * For more information see RFC 1662 (p. 10) + *---------------------------------------------------------------------------*/ +const u_short HDLC_FCS_TAB[256] = { 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 +}; + +/*---------------------------------------------------------------------------* + * HDLC bit table + * ============== + * + * bits[0..3]: A value which tells how many set bits there are at the + * beginning of the byte. + * + * bits[4..7]: Special bytes like 0x7e, 0x7d, 0xfd ... are flagged here + * NOTE: Special bytes also means 'abort' bytes (7 or more + * continious set bits) + * + * bits[8..11]: A copy of bits[0..3] but only incremented by one. + * NOTE: 0x7e has value '8' instead of '0'. Internal reasons. + * + * bits[12..15]: A value which tells how many set bits there are at the + * end of the byte. + * NOTE: 0xff has both '8' incoming and '8' outgoing bits. + * + *---------------------------------------------------------------------------*/ +const u_short HDLC_BIT_TAB[256] = { 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0504, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0605, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0504, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0160, 0x0706, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0504, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0605, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0504, 0x0100, + 0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100, + 0x0201, 0x0100, 0x0302, 0x01a0, 0x02a1, 0x0860, 0x0807, 0x1100, + 0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1403, 0x1100, + 0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1504, 0x1100, + 0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1403, 0x1100, + 0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1605, 0x1100, + 0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1403, 0x1100, + 0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1504, 0x1100, + 0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1403, 0x1100, + 0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1160, 0x1706, 0x2100, + 0x2201, 0x2100, 0x2302, 0x2100, 0x2201, 0x2100, 0x2403, 0x2100, + 0x2201, 0x2100, 0x2302, 0x2100, 0x2201, 0x2100, 0x2504, 0x2100, + 0x2201, 0x2100, 0x2302, 0x2100, 0x2201, 0x2100, 0x2403, 0x2100, + 0x2201, 0x2100, 0x2302, 0x2100, 0x2201, 0x2100, 0x2605, 0x3100, + 0x3201, 0x3100, 0x3302, 0x3100, 0x3201, 0x3100, 0x3403, 0x3100, + 0x3201, 0x3100, 0x3302, 0x3100, 0x3201, 0x3100, 0x3504, 0x4100, + 0x4201, 0x4100, 0x4302, 0x4100, 0x4201, 0x4100, 0x4403, 0x5100, + 0x5201, 0x5100, 0x5302, 0x6180, 0x6281, 0x7150, 0x8908 +}; + +/*---------------------------------------------------------------------------* + * HDLC_DECODE + * =========== + * + * u_char: flag, blevel + * u_short: crc, ib, tmp, tmp2, len + * + * next: 'continue' or 'goto xxx' + * + * cfr: complet frame + * nfr: new frame + * NOTE: must setup 'len' and 'dst', so that 'dst' may be written + * at most 'len' times. + * + * rab: abort + * rdd: read data (read byte is stored in 'tmp2') + * rdo: overflow + * + * d: dummy + * + * NOTE: setting flag to '0' and len to '0' => recover from rdu + * NOTE: bits[8 .. ] of tmp2 may be used to store custom data/flags + * NOTE: these variables have to be 'suspended' / 'resumed' somehow: + * flag, blevel, crc, ib, tmp, len + * NOTE: zero is default value for all variables. + * NOTE: each time 'dst' is written, 'len' is decremented by one. + *---------------------------------------------------------------------------*/ + +#define HDLC_DECODE(dst, len, tmp, tmp2, blevel, ib, crc, flag, rddcmd, nfrcmd, \ + cfrcmd, rabcmd, rdocmd, nextcmd, d) \ + \ + rddcmd; \ + \ + ib += HDLC_BIT_TAB[(u_char)tmp2]; \ + \ + if ((u_char)ib >= 5) \ + { \ + if (ib & 0x20) /* de-stuff (msb) */ \ + { \ + if ((u_char)tmp2 == 0x7e) goto j0##d; \ + tmp2 += tmp2 & 0x7f; \ + blevel--; \ + \ + if ((ib += 0x100) & 0xc) tmp2 |= 1; /* */ \ + } \ + \ + ib &= ~0xe0; \ + \ + if ((u_char)ib == 6) /* flag seq (lsb) */ \ + { \ + j0##d: if (flag >= 2) \ + { \ + len += (4 - flag) & 3; /* remove CRC bytes */ \ + crc ^= 0xf0b8; \ + cfrcmd; \ + len = 0; \ + } \ + \ + flag = 1; \ + \ + blevel = (ib >> 8) & 0xf; \ + tmp = ((u_char)tmp2) >> blevel; \ + blevel = 8 - blevel; \ + \ + ib >>= 12; \ + \ + nextcmd; \ + } \ + if ((u_char)ib >= 7) /* abort (msb & lsb) */ \ + { \ + if (flag >= 2) \ + { \ + rabcmd; \ + len = 0; \ + } \ + \ + flag = 0; \ + \ + ib >>= 12; \ + \ + nextcmd; \ + } \ + if ((u_char)ib == 5) /* de-stuff (lsb) */ \ + { \ + tmp2 = (tmp2 | (tmp2 + 1)) & ~0x1; \ + blevel--; \ + } \ + if (blevel > 7) /* EO - bits */ \ + { \ + tmp |= (u_char)tmp2 >> (8 - (blevel &= 7)); \ + \ + ib >>= 12; \ + \ + nextcmd; \ + } \ + } \ + \ + tmp |= (u_char)tmp2 << blevel; \ + \ + if (!len--) \ + { \ + len++; \ + \ + if (!flag++) { flag--; goto j5##d;} /* hunt mode */ \ + \ + switch (flag) \ + { case 2: /* new frame */ \ + nfrcmd; \ + crc = -1; \ + if (!len--) { len++; flag++; goto j4##d; } \ + goto j3##d; \ + case 3: /* CRC (lsb's) */ \ + case 4: /* CRC (msb's) */ \ + goto j4##d; \ + case 5: /* RDO */ \ + rdocmd; \ + flag = 0; \ + break; \ + } \ + } \ + else \ + { \ + j3##d: dst = (u_char)tmp; \ + j4##d: crc = (HDLC_FCS_TAB[(u_char)(tmp ^ crc)] ^ (u_char)(crc >> 8)); \ + } \ + \ + j5##d: ib >>= 12; \ + tmp >>= 8; \ + +/*------ end of HDLC_DECODE -------------------------------------------------*/ + + +/*---------------------------------------------------------------------------* + * HDLC_ENCODE + * =========== + * + * u_char: flag, src + * u_short: tmp2, blevel, ib, crc, len + * u_int: tmp + * + * gfr: get new frame, free old, and exit if no frame + * NOTE: must setup 'len' and 'src', so that 'src' can be read + * 'len' times. + * + * wrd: write data (output = (u_char)tmp) + * + * d: dummy + * + * NOTE: setting flag to '-1' and len to '0' => abort byte will be sent + * NOTE: these variables have to be 'suspended' / 'resumed' somehow: + * flag, blevel, crc, ib, tmp, len + * NOTE: zero is default value for all variables. + * NOTE: each time 'src' is read, 'len' is decremented by one. + * NOTE: gfr must setup 'len'. + *---------------------------------------------------------------------------*/ + +#define HDLC_ENCODE(src, len, tmp, tmp2, blevel, ib, crc, flag, gfrcmd, wrdcmd, d) \ + \ + if (blevel >= 0x800) { blevel -= 0x800; goto j4##d; } \ + \ + if (!len--) \ + { \ + len++; \ + \ + switch(++flag) \ + { case 0: /* abort */ \ + tmp = blevel = 0; /* zero is default */ \ + tmp2 = 0xff; \ + goto j3##d; \ + case 1: /* 1st time FS */ \ + case 2: /* 2nd time FS */ \ + tmp2 = 0x7e; \ + goto j3##d; \ + case 3: /* get new frame */ \ + flag--; \ + gfrcmd; \ + flag++; \ + crc = -1; \ + ib = 0; \ + if (!len--) { len++; flag++; goto j0##d; } \ + goto j1##d; /* first byte */ \ + case 4: /* CRC (lsb's) */ \ + j0##d: \ + crc ^= -1; \ + case 5: /* CRC (msb's) */ \ + tmp2 = (u_char)crc; \ + crc >>= 8; \ + goto j2##d; /* CRC stuff */ \ + case 6: /* frame done */ \ + tmp2 = 0x7e; /* end FS */ \ + flag = 1; \ + goto j3##d; \ + } \ + } \ + else \ + { j1##d : \ + tmp2 = (u_char)src; \ + crc =(HDLC_FCS_TAB[(u_char)(crc ^ tmp2)] ^ (u_char)(crc >> 8)); \ + j2##d: \ + \ + ib >>= 12; \ + ib += HDLC_BIT_TAB[(u_char)tmp2]; \ + \ + if ((u_char)ib >= 5) /* stuffing */ \ + { \ + blevel &= ~0xff; \ + \ + if (ib & 0xc0) /* bit stuff (msb) */ \ + { \ + tmp2 += tmp2 & (0xff * (ib & 0xc0)); \ + ib %= 0x5000; \ + blevel++; \ + } \ + \ + ib &= ~0xf0; \ + \ + if ((u_char)ib >= 5) /* bit stuff (lsb) */ \ + { \ + tmp2 += tmp2 & ~0x1f >> ((ib - (ib >> 8) + 1) \ + & 7); \ + blevel++; \ + \ + if ((u_char)ib >= 10) /* bit stuff (msb) */ \ + { \ + tmp2 += tmp2 & ~0x7ff >> ((ib - \ + (ib >> 8) + 1) & 7); \ + blevel++; \ + } \ + if (ib & 0x8000) /* bit walk */ \ + { \ + ib = ((u_char)ib % 5) << 12; \ + } \ + } \ + \ + tmp |= tmp2 << (u_char)(blevel >> 8); \ + blevel += (u_char)blevel << 8; \ + } \ + else /* no stuffing */ \ + { \ + j3##d:tmp |= tmp2 << (u_char)(blevel >> 8); \ + } \ + } \ + \ + j4##d: wrdcmd; \ + tmp >>= 8; \ + +/*------ end of HDLC_ENCODE -------------------------------------------------*/ + + +#endif /* _I4B_HDLC_H_ */ |
