hdlc.c revision 26516 
1/*
2 *	     PPP High Level Link Control (HDLC) Module
3 *
4 *	    Written by Toshiharu OHNO (tony-o@iij.ad.jp)
5 *
6 *   Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
7 *
8 * Redistribution and use in source and binary forms are permitted
9 * provided that the above copyright notice and this paragraph are
10 * duplicated in all such forms and that any documentation,
11 * advertising materials, and other materials related to such
12 * distribution and use acknowledge that the software was developed
13 * by the Internet Initiative Japan, Inc.  The name of the
14 * IIJ may not be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
19 *
20 * $Id: hdlc.c,v 1.15 1997/05/26 00:43:59 brian Exp $
21 *
22 *	TODO:
23 */
24#include "fsm.h"
25#include "hdlc.h"
26#include "lcpproto.h"
27#include "lcp.h"
28#include "lqr.h"
29#include "loadalias.h"
30#include "vars.h"
31#include "pred.h"
32#include "modem.h"
33#include "ccp.h"
34
35struct hdlcstat {
36  int	badfcs;
37  int	badaddr;
38  int	badcommand;
39  int	unknownproto;
40} HdlcStat;
41
42static int ifOutPackets, ifOutOctets, ifOutLQRs;
43static int ifInPackets, ifInOctets;
44
45struct protostat {
46  u_short number;
47  char *name;
48  u_long in_count;
49  u_long out_count;
50} ProtocolStat[] = {
51  { PROTO_IP,		"IP" },
52  { PROTO_VJUNCOMP,	"VJ_UNCOMP" },
53  { PROTO_VJCOMP,	"VJ_COMP" },
54  { PROTO_COMPD,	"COMPD" },
55  { PROTO_LCP,		"LCP" },
56  { PROTO_IPCP,		"IPCP" },
57  { PROTO_CCP,		"CCP" },
58  { PROTO_PAP,		"PAP" },
59  { PROTO_LQR,		"LQR" },
60  { PROTO_CHAP,		"CHAP" },
61  { 0,			"Others" },
62};
63
64static u_short const fcstab[256] = {
65/* 00 */    0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
66/* 08 */    0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
67/* 10 */    0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
68/* 18 */    0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
69/* 20 */    0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
70/* 28 */    0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
71/* 30 */    0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
72/* 38 */    0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
73/* 40 */    0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
74/* 48 */    0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
75/* 50 */    0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
76/* 58 */    0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
77/* 60 */    0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
78/* 68 */    0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
79/* 70 */    0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
80/* 78 */    0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
81/* 80 */    0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
82/* 88 */    0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
83/* 90 */    0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
84/* 98 */    0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
85/* a0 */    0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
86/* a8 */    0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
87/* b0 */    0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
88/* b8 */    0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
89/* c0 */    0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
90/* c8 */    0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
91/* d0 */    0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
92/* d8 */    0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
93/* e0 */    0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
94/* e8 */    0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
95/* f0 */    0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
96/* f8 */    0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
97};
98
99void
100HdlcInit()
101{
102  ifInOctets = ifOutOctets = 0;
103  ifInPackets = ifOutPackets = 0;
104  ifOutLQRs = 0;
105}
106
107/*
108 *  HDLC FCS computation. Read RFC 1171 Appendix B and CCITT X.25 section
109 *  2.27 for further details.
110 */
111inline u_short
112HdlcFcs(u_short fcs, u_char *cp, int len)
113{
114  while (len--)
115    fcs = (fcs >> 8) ^ fcstab[(fcs ^ *cp++) & 0xff];
116  return(fcs);
117}
118
119void
120HdlcOutput(int pri, u_short proto, struct mbuf *bp)
121{
122  struct mbuf *mhp, *mfcs;
123  struct protostat *statp;
124  struct lqrdata *lqr;
125  u_char *cp;
126  u_short fcs;
127
128  if ((proto & 0xfff1) == 0x21) {	/* Network Layer protocol */
129    if (CcpFsm.state == ST_OPENED) {
130      Pred1Output(pri, proto, bp);
131      return;
132    }
133  }
134  if (DEV_IS_SYNC)
135    mfcs = NULLBUFF;
136  else
137    mfcs = mballoc(2, MB_HDLCOUT);
138  mhp = mballoc(4, MB_HDLCOUT);
139  mhp->cnt = 0;
140  cp = MBUF_CTOP(mhp);
141  if (proto == PROTO_LCP || LcpInfo.his_acfcomp == 0) {
142    *cp++ = HDLC_ADDR;
143    *cp++ = HDLC_UI;
144    mhp->cnt += 2;
145  }
146  /*
147   *  If possible, compress protocol field.
148   */
149  if (LcpInfo.his_protocomp && (proto & 0xff00) == 0) {
150    *cp++ = proto;
151    mhp->cnt++;
152  } else {
153    *cp++ = proto >> 8;
154    *cp = proto & 0377;
155    mhp->cnt += 2;
156  }
157  mhp->next = bp;
158  bp->next = mfcs;
159
160  lqr = &MyLqrData;
161  lqr->PeerOutPackets = ifOutPackets++;
162  ifOutOctets += plength(mhp) + 1;
163  lqr->PeerOutOctets = ifOutOctets;
164
165  if (proto == PROTO_LQR) {
166    lqr->MagicNumber = LcpInfo.want_magic;
167    lqr->LastOutLQRs = HisLqrData.PeerOutLQRs;
168    lqr->LastOutPackets = HisLqrData.PeerOutPackets;
169    lqr->LastOutOctets = HisLqrData.PeerOutOctets;
170    lqr->PeerInLQRs = HisLqrSave.SaveInLQRs;
171    lqr->PeerInPackets = HisLqrSave.SaveInPackets;
172    lqr->PeerInDiscards = HisLqrSave.SaveInDiscards;
173    lqr->PeerInErrors = HisLqrSave.SaveInErrors;
174    lqr->PeerInOctets = HisLqrSave.SaveInOctets;
175    lqr->PeerOutLQRs = ++ifOutLQRs;
176    LqrDump("LqrOutput", lqr);
177    LqrChangeOrder(lqr, (struct lqrdata *)(MBUF_CTOP(bp)));
178  }
179
180  if (!DEV_IS_SYNC) {
181    fcs = HdlcFcs(INITFCS, MBUF_CTOP(mhp), mhp->cnt);
182    fcs = HdlcFcs(fcs, MBUF_CTOP(bp), bp->cnt);
183    fcs = ~fcs;
184    cp = MBUF_CTOP(mfcs);
185    *cp++ = fcs & 0377;	/* Low byte first!! */
186    *cp++ = fcs >> 8;
187  }
188
189  LogDumpBp(LogHDLC, "HdlcOutput", mhp);
190  for (statp = ProtocolStat; statp->number; statp++)
191    if (statp->number == proto)
192      break;
193  statp->out_count++;
194  if (DEV_IS_SYNC)
195    ModemOutput(pri, mhp);
196  else
197    AsyncOutput(pri, mhp, proto);
198}
199
200void
201DecodePacket(u_short proto, struct mbuf *bp)
202{
203  u_char *cp;
204
205  LogPrintf(LogDEBUG, "DecodePacket: proto = %04x\n", proto);
206
207  switch (proto) {
208  case PROTO_LCP:
209    LcpInput(bp);
210    break;
211  case PROTO_PAP:
212    PapInput(bp);
213    break;
214  case PROTO_LQR:
215    HisLqrSave.SaveInLQRs++;
216    LqrInput(bp);
217    break;
218  case PROTO_CHAP:
219    ChapInput(bp);
220    break;
221  case PROTO_VJUNCOMP:
222  case PROTO_VJCOMP:
223    bp = VjCompInput(bp, proto);
224    if (bp == NULLBUFF) {
225      break;
226    }
227    /* fall down */
228  case PROTO_IP:
229    IpInput(bp);
230    break;
231  case PROTO_IPCP:
232    IpcpInput(bp);
233    break;
234  case PROTO_CCP:
235    CcpInput(bp);
236    break;
237  case PROTO_COMPD:
238    Pred1Input(bp);
239    break;
240  default:
241    LogPrintf(LogPHASE, "Unknown protocol 0x%04x\n", proto);
242    bp->offset -= 2;
243    bp->cnt += 2;
244    cp = MBUF_CTOP(bp);
245    LcpSendProtoRej(cp,  bp->cnt);
246    HisLqrSave.SaveInDiscards++;
247    HdlcStat.unknownproto++;
248    pfree(bp);
249    break;
250  }
251}
252
253int
254ReportProtStatus()
255{
256  struct protostat *statp;
257  int cnt;
258
259  statp = ProtocolStat;
260  statp--;
261  cnt = 0;
262  fprintf(VarTerm, "    Protocol     in        out      Protocol      in       out\n");
263  do {
264    statp++;
265    fprintf(VarTerm, "   %-9s: %8lu, %8lu",
266      statp->name, statp->in_count, statp->out_count);
267    if (++cnt == 2) {
268      fprintf(VarTerm, "\n");
269      cnt = 0;
270    }
271  } while (statp->number);
272  if (cnt)
273     fprintf(VarTerm, "\n");
274  return(1);
275}
276
277int
278ReportHdlcStatus()
279{
280  struct hdlcstat *hp = &HdlcStat;
281
282  if (VarTerm) {
283    fprintf(VarTerm, "HDLC level errors\n\n");
284    fprintf(VarTerm, "FCS: %u  ADDR: %u  COMMAND: %u  PROTO: %u\n",
285	  hp->badfcs, hp->badaddr, hp->badcommand, hp->unknownproto);
286  }
287  return 0;
288}
289
290static struct hdlcstat laststat;
291
292void
293HdlcErrorCheck()
294{
295  struct hdlcstat *hp = &HdlcStat;
296  struct hdlcstat *op = &laststat;
297
298  if (bcmp(hp, op, sizeof(laststat))) {
299    LogPrintf(LogPHASE, "HDLC errors -> FCS: %u ADDR: %u COMD: %u PROTO: %u\n",
300	hp->badfcs - op->badfcs, hp->badaddr - op->badaddr,
301	hp->badcommand - op->badcommand, hp->unknownproto - op->unknownproto);
302  }
303  laststat = HdlcStat;
304}
305
306void
307HdlcInput(struct mbuf *bp)
308{
309  u_short fcs, proto;
310  u_char *cp, addr, ctrl;
311  struct protostat *statp;
312
313  LogDumpBp(LogHDLC, "HdlcInput:", bp);
314  if (DEV_IS_SYNC)
315    fcs = GOODFCS;
316  else
317    fcs = HdlcFcs(INITFCS, MBUF_CTOP(bp), bp->cnt);
318  HisLqrSave.SaveInOctets += bp->cnt + 1;
319
320  LogPrintf(LogDEBUG, "HdlcInput: fcs = %04x (%s)\n",
321	    fcs, (fcs == GOODFCS)? "good" : "bad");
322  if (fcs != GOODFCS) {
323    HisLqrSave.SaveInErrors++;
324    LogPrintf(LogDEBUG, "HdlcInput: Bad FCS\n");
325    HdlcStat.badfcs++;
326    pfree(bp);
327    return;
328  }
329  if (!DEV_IS_SYNC)
330    bp->cnt -= 2;		/* discard FCS part */
331
332  if (bp->cnt < 2) {		/* XXX: raise this bar ? */
333	pfree(bp);
334	return;
335  }
336
337  cp = MBUF_CTOP(bp);
338
339  ifInPackets++;
340  ifInOctets += bp->cnt;
341
342  if (!LcpInfo.want_acfcomp) {
343    /*
344     *  We expect that packet is not compressed.
345     */
346    addr = *cp++;
347    if (addr != HDLC_ADDR) {
348      HisLqrSave.SaveInErrors++;
349      HdlcStat.badaddr++;
350      LogPrintf(LogDEBUG, "HdlcInput: addr %02x\n", *cp);
351      pfree(bp);
352      return;
353    }
354
355    ctrl = *cp++;
356    if (ctrl != HDLC_UI) {
357      HisLqrSave.SaveInErrors++;
358      HdlcStat.badcommand++;
359      LogPrintf(LogDEBUG, "HdlcInput: %02x\n", *cp);
360      pfree(bp);
361      return;
362    }
363    bp->offset += 2;
364    bp->cnt -= 2;
365  } else if (cp[0] == HDLC_ADDR && cp[1] == HDLC_UI) {
366    /*
367     *  We can receive compressed packet, but peer still send
368     *  uncompressed packet to me.
369     */
370    cp += 2;
371    bp->offset += 2;
372    bp->cnt -= 2;
373  }
374
375  if (LcpInfo.want_protocomp) {
376    proto = 0;
377    cp--;
378    do {
379      cp++; bp->offset++; bp->cnt--;
380      proto = proto << 8;
381      proto += *cp;
382    } while (!(proto & 1));
383  } else {
384    proto = *cp++ << 8;
385    proto |= *cp++;
386    bp->offset += 2;
387    bp->cnt -= 2;
388  }
389
390  for (statp = ProtocolStat; statp->number; statp++)
391    if (statp->number == proto)
392      break;
393  statp->in_count++;
394  HisLqrSave.SaveInPackets++;
395
396  DecodePacket(proto, bp);
397}
398