hdlc.c revision 29295 
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 1.18 1997/09/10 21:33:32 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
52  {
53    PROTO_IP, "IP"
54  },
55  {
56    PROTO_VJUNCOMP, "VJ_UNCOMP"
57  },
58  {
59    PROTO_VJCOMP, "VJ_COMP"
60  },
61  {
62    PROTO_COMPD, "COMPD"
63  },
64  {
65    PROTO_LCP, "LCP"
66  },
67  {
68    PROTO_IPCP, "IPCP"
69  },
70  {
71    PROTO_CCP, "CCP"
72  },
73  {
74    PROTO_PAP, "PAP"
75  },
76  {
77    PROTO_LQR, "LQR"
78  },
79  {
80    PROTO_CHAP, "CHAP"
81  },
82  {
83    0, "Others"
84  },
85};
86
87static u_short const fcstab[256] = {
88   /* 00 */ 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
89   /* 08 */ 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
90   /* 10 */ 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
91   /* 18 */ 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
92   /* 20 */ 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
93   /* 28 */ 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
94   /* 30 */ 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
95   /* 38 */ 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
96   /* 40 */ 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
97   /* 48 */ 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
98   /* 50 */ 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
99   /* 58 */ 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
100   /* 60 */ 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
101   /* 68 */ 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
102   /* 70 */ 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
103   /* 78 */ 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
104   /* 80 */ 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
105   /* 88 */ 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
106   /* 90 */ 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
107   /* 98 */ 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
108   /* a0 */ 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
109   /* a8 */ 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
110   /* b0 */ 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
111   /* b8 */ 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
112   /* c0 */ 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
113   /* c8 */ 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
114   /* d0 */ 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
115   /* d8 */ 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
116   /* e0 */ 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
117   /* e8 */ 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
118   /* f0 */ 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
119   /* f8 */ 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
120};
121
122u_char EscMap[33];
123
124void
125HdlcInit()
126{
127  ifInOctets = ifOutOctets = 0;
128  ifInPackets = ifOutPackets = 0;
129  ifOutLQRs = 0;
130}
131
132/*
133 *  HDLC FCS computation. Read RFC 1171 Appendix B and CCITT X.25 section
134 *  2.27 for further details.
135 */
136inline u_short
137HdlcFcs(u_short fcs, u_char * cp, int len)
138{
139  while (len--)
140    fcs = (fcs >> 8) ^ fcstab[(fcs ^ *cp++) & 0xff];
141  return (fcs);
142}
143
144void
145HdlcOutput(int pri, u_short proto, struct mbuf * bp)
146{
147  struct mbuf *mhp, *mfcs;
148  struct protostat *statp;
149  struct lqrdata *lqr;
150  u_char *cp;
151  u_short fcs;
152
153  if ((proto & 0xfff1) == 0x21) {	/* Network Layer protocol */
154    if (CcpFsm.state == ST_OPENED) {
155      if (CcpInfo.want_proto == TY_PRED1) {
156        Pred1Output(pri, proto, bp);
157        return;
158      }
159    }
160  }
161  if (DEV_IS_SYNC)
162    mfcs = NULLBUFF;
163  else
164    mfcs = mballoc(2, MB_HDLCOUT);
165  mhp = mballoc(4, MB_HDLCOUT);
166  mhp->cnt = 0;
167  cp = MBUF_CTOP(mhp);
168  if (proto == PROTO_LCP || LcpInfo.his_acfcomp == 0) {
169    *cp++ = HDLC_ADDR;
170    *cp++ = HDLC_UI;
171    mhp->cnt += 2;
172  }
173
174  /*
175   * If possible, compress protocol field.
176   */
177  if (LcpInfo.his_protocomp && (proto & 0xff00) == 0) {
178    *cp++ = proto;
179    mhp->cnt++;
180  } else {
181    *cp++ = proto >> 8;
182    *cp = proto & 0377;
183    mhp->cnt += 2;
184  }
185  mhp->next = bp;
186  bp->next = mfcs;
187
188  lqr = &MyLqrData;
189  lqr->PeerOutPackets = ifOutPackets++;
190  ifOutOctets += plength(mhp) + 1;
191  lqr->PeerOutOctets = ifOutOctets;
192
193  if (proto == PROTO_LQR) {
194    lqr->MagicNumber = LcpInfo.want_magic;
195    lqr->LastOutLQRs = HisLqrData.PeerOutLQRs;
196    lqr->LastOutPackets = HisLqrData.PeerOutPackets;
197    lqr->LastOutOctets = HisLqrData.PeerOutOctets;
198    lqr->PeerInLQRs = HisLqrSave.SaveInLQRs;
199    lqr->PeerInPackets = HisLqrSave.SaveInPackets;
200    lqr->PeerInDiscards = HisLqrSave.SaveInDiscards;
201    lqr->PeerInErrors = HisLqrSave.SaveInErrors;
202    lqr->PeerInOctets = HisLqrSave.SaveInOctets;
203    lqr->PeerOutLQRs = ++ifOutLQRs;
204    LqrDump("LqrOutput", lqr);
205    LqrChangeOrder(lqr, (struct lqrdata *) (MBUF_CTOP(bp)));
206  }
207  if (!DEV_IS_SYNC) {
208    fcs = HdlcFcs(INITFCS, MBUF_CTOP(mhp), mhp->cnt);
209    fcs = HdlcFcs(fcs, MBUF_CTOP(bp), bp->cnt);
210    fcs = ~fcs;
211    cp = MBUF_CTOP(mfcs);
212    *cp++ = fcs & 0377;		/* Low byte first!! */
213    *cp++ = fcs >> 8;
214  }
215  LogDumpBp(LogHDLC, "HdlcOutput", mhp);
216  for (statp = ProtocolStat; statp->number; statp++)
217    if (statp->number == proto)
218      break;
219  statp->out_count++;
220  if (DEV_IS_SYNC)
221    ModemOutput(pri, mhp);
222  else
223    AsyncOutput(pri, mhp, proto);
224}
225
226void
227DecodePacket(u_short proto, struct mbuf * bp)
228{
229  u_char *cp;
230
231  LogPrintf(LogDEBUG, "DecodePacket: proto = %04x\n", proto);
232
233  switch (proto) {
234  case PROTO_LCP:
235    LcpInput(bp);
236    break;
237  case PROTO_PAP:
238    PapInput(bp);
239    break;
240  case PROTO_LQR:
241    HisLqrSave.SaveInLQRs++;
242    LqrInput(bp);
243    break;
244  case PROTO_CHAP:
245    ChapInput(bp);
246    break;
247  case PROTO_VJUNCOMP:
248  case PROTO_VJCOMP:
249    bp = VjCompInput(bp, proto);
250    if (bp == NULLBUFF) {
251      break;
252    }
253    /* fall down */
254  case PROTO_IP:
255    IpInput(bp);
256    break;
257  case PROTO_IPCP:
258    IpcpInput(bp);
259    break;
260  case PROTO_CCP:
261    CcpInput(bp);
262    break;
263  case PROTO_COMPD:
264    Pred1Input(bp);
265    break;
266  default:
267    LogPrintf(LogPHASE, "Unknown protocol 0x%04x\n", proto);
268    bp->offset -= 2;
269    bp->cnt += 2;
270    cp = MBUF_CTOP(bp);
271    LcpSendProtoRej(cp, bp->cnt);
272    HisLqrSave.SaveInDiscards++;
273    HdlcStat.unknownproto++;
274    pfree(bp);
275    break;
276  }
277}
278
279int
280ReportProtStatus()
281{
282  struct protostat *statp;
283  int cnt;
284
285  statp = ProtocolStat;
286  statp--;
287  cnt = 0;
288  fprintf(VarTerm, "    Protocol     in        out      Protocol      in       out\n");
289  do {
290    statp++;
291    fprintf(VarTerm, "   %-9s: %8lu, %8lu",
292	    statp->name, statp->in_count, statp->out_count);
293    if (++cnt == 2) {
294      fprintf(VarTerm, "\n");
295      cnt = 0;
296    }
297  } while (statp->number);
298  if (cnt)
299    fprintf(VarTerm, "\n");
300  return (1);
301}
302
303int
304ReportHdlcStatus()
305{
306  struct hdlcstat *hp = &HdlcStat;
307
308  if (VarTerm) {
309    fprintf(VarTerm, "HDLC level errors\n\n");
310    fprintf(VarTerm, "FCS: %u  ADDR: %u  COMMAND: %u  PROTO: %u\n",
311	    hp->badfcs, hp->badaddr, hp->badcommand, hp->unknownproto);
312  }
313  return 0;
314}
315
316static struct hdlcstat laststat;
317
318void
319HdlcErrorCheck()
320{
321  struct hdlcstat *hp = &HdlcStat;
322  struct hdlcstat *op = &laststat;
323
324  if (bcmp(hp, op, sizeof(laststat))) {
325    LogPrintf(LogPHASE, "HDLC errors -> FCS: %u ADDR: %u COMD: %u PROTO: %u\n",
326	      hp->badfcs - op->badfcs, hp->badaddr - op->badaddr,
327      hp->badcommand - op->badcommand, hp->unknownproto - op->unknownproto);
328  }
329  laststat = HdlcStat;
330}
331
332void
333HdlcInput(struct mbuf * bp)
334{
335  u_short fcs, proto;
336  u_char *cp, addr, ctrl;
337  struct protostat *statp;
338
339  LogDumpBp(LogHDLC, "HdlcInput:", bp);
340  if (DEV_IS_SYNC)
341    fcs = GOODFCS;
342  else
343    fcs = HdlcFcs(INITFCS, MBUF_CTOP(bp), bp->cnt);
344  HisLqrSave.SaveInOctets += bp->cnt + 1;
345
346  LogPrintf(LogDEBUG, "HdlcInput: fcs = %04x (%s)\n",
347	    fcs, (fcs == GOODFCS) ? "good" : "bad");
348  if (fcs != GOODFCS) {
349    HisLqrSave.SaveInErrors++;
350    LogPrintf(LogDEBUG, "HdlcInput: Bad FCS\n");
351    HdlcStat.badfcs++;
352    pfree(bp);
353    return;
354  }
355  if (!DEV_IS_SYNC)
356    bp->cnt -= 2;		/* discard FCS part */
357
358  if (bp->cnt < 2) {		/* XXX: raise this bar ? */
359    pfree(bp);
360    return;
361  }
362  cp = MBUF_CTOP(bp);
363
364  ifInPackets++;
365  ifInOctets += bp->cnt;
366
367  if (!LcpInfo.want_acfcomp) {
368
369    /*
370     * We expect that packet is not compressed.
371     */
372    addr = *cp++;
373    if (addr != HDLC_ADDR) {
374      HisLqrSave.SaveInErrors++;
375      HdlcStat.badaddr++;
376      LogPrintf(LogDEBUG, "HdlcInput: addr %02x\n", *cp);
377      pfree(bp);
378      return;
379    }
380    ctrl = *cp++;
381    if (ctrl != HDLC_UI) {
382      HisLqrSave.SaveInErrors++;
383      HdlcStat.badcommand++;
384      LogPrintf(LogDEBUG, "HdlcInput: %02x\n", *cp);
385      pfree(bp);
386      return;
387    }
388    bp->offset += 2;
389    bp->cnt -= 2;
390  } else if (cp[0] == HDLC_ADDR && cp[1] == HDLC_UI) {
391
392    /*
393     * We can receive compressed packet, but peer still send uncompressed
394     * packet to me.
395     */
396    cp += 2;
397    bp->offset += 2;
398    bp->cnt -= 2;
399  }
400  if (LcpInfo.want_protocomp) {
401    proto = 0;
402    cp--;
403    do {
404      cp++;
405      bp->offset++;
406      bp->cnt--;
407      proto = proto << 8;
408      proto += *cp;
409    } while (!(proto & 1));
410  } else {
411    proto = *cp++ << 8;
412    proto |= *cp++;
413    bp->offset += 2;
414    bp->cnt -= 2;
415  }
416
417  for (statp = ProtocolStat; statp->number; statp++)
418    if (statp->number == proto)
419      break;
420  statp->in_count++;
421  HisLqrSave.SaveInPackets++;
422
423  DecodePacket(proto, bp);
424}
425