xref: /freebsd/usr.sbin/ppp/hdlc.c (revision 5ebc7e6281887681c3a348a5a4c902e262ccd656)
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 1.2 1995/02/26 12:17:30 amurai 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 "vars.h"
30 
31 struct hdlcstat {
32   int	badfcs;
33   int	badaddr;
34   int	badcommand;
35   int	unknownproto;
36 } HdlcStat;
37 
38 static int ifOutPackets, ifOutOctets, ifOutLQRs;
39 static int ifInPackets, ifInOctets;
40 
41 struct protostat {
42   u_short number;
43   char *name;
44   u_long in_count;
45   u_long out_count;
46 } ProtocolStat[] = {
47   { PROTO_IP,		"IP" },
48   { PROTO_VJUNCOMP,	"VJ_UNCOMP" },
49   { PROTO_VJCOMP,	"VJ_COMP" },
50   { PROTO_COMPD,	"COMPD" },
51   { PROTO_LCP,		"LCP" },
52   { PROTO_IPCP,		"IPCP" },
53   { PROTO_CCP,		"CCP" },
54   { PROTO_PAP,		"PAP" },
55   { PROTO_LQR,		"LQR" },
56   { PROTO_CHAP,		"CHAP" },
57   { 0,			"Others" },
58 };
59 
60 static u_short fcstab[256] = {
61 /* 00 */    0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
62 /* 08 */    0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
63 /* 10 */    0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
64 /* 18 */    0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
65 /* 20 */    0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
66 /* 28 */    0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
67 /* 30 */    0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
68 /* 38 */    0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
69 /* 40 */    0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
70 /* 48 */    0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
71 /* 50 */    0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
72 /* 58 */    0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
73 /* 60 */    0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
74 /* 68 */    0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
75 /* 70 */    0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
76 /* 78 */    0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
77 /* 80 */    0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
78 /* 88 */    0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
79 /* 90 */    0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
80 /* 98 */    0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
81 /* a0 */    0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
82 /* a8 */    0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
83 /* b0 */    0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
84 /* b8 */    0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
85 /* c0 */    0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
86 /* c8 */    0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
87 /* d0 */    0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
88 /* d8 */    0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
89 /* e0 */    0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
90 /* e8 */    0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
91 /* f0 */    0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
92 /* f8 */    0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
93 };
94 
95 void
96 HdlcInit()
97 {
98   ifInOctets = ifOutOctets = 0;
99   ifInPackets = ifOutPackets = 0;
100   ifOutLQRs = 0;
101 }
102 
103 /*
104  *  HDLC FCS computation. Read RFC 1171 Appendix B and CCITT X.25 section
105  *  2.27 for further details.
106  */
107 u_short
108 HdlcFcs(fcs, cp, len)
109 u_short fcs;
110 u_char *cp;
111 int len;
112 {
113   while (len--)
114     fcs = (fcs >> 8) ^ fcstab[(fcs ^ *cp++) & 0xff];
115   return(fcs);
116 }
117 
118 void
119 HdlcOutput(int pri, u_short proto, struct mbuf *bp)
120 {
121   struct mbuf *mhp, *mfcs;
122   struct protostat *statp;
123   struct lqrdata *lqr;
124   u_char *cp;
125   u_short fcs;
126 
127   if ((proto & 0xfff1) == 0x21) {	/* Network Layer protocol */
128     if (CcpFsm.state == ST_OPENED) {
129       Pred1Output(pri, proto, bp);
130       return;
131     }
132   }
133   if (DEV_IS_SYNC)
134     mfcs = NULLBUFF;
135   else
136     mfcs = mballoc(2, MB_HDLCOUT);
137   mhp = mballoc(4, MB_HDLCOUT);
138   mhp->cnt = 0;
139   cp = MBUF_CTOP(mhp);
140   if (proto == PROTO_LCP || LcpInfo.his_acfcomp == 0) {
141     *cp++ = HDLC_ADDR;
142     *cp++ = HDLC_UI;
143     mhp->cnt += 2;
144   }
145   /*
146    *  If possible, compress protocol field.
147    */
148   if (LcpInfo.his_protocomp && (proto & 0xff00) == 0) {
149     *cp++ = proto;
150     mhp->cnt++;
151   } else {
152     *cp++ = proto >> 8;
153     *cp = proto & 0377;
154     mhp->cnt += 2;
155   }
156   mhp->next = bp;
157   bp->next = mfcs;
158 
159   lqr = &MyLqrData;
160   lqr->PeerOutPackets = ifOutPackets++;
161   ifOutOctets += plength(mhp) + 1;
162   lqr->PeerOutOctets = ifOutOctets;
163 
164   if (proto == PROTO_LQR) {
165     lqr->MagicNumber = LcpInfo.want_magic;
166     lqr->LastOutLQRs = HisLqrData.PeerOutLQRs;
167     lqr->LastOutPackets = HisLqrData.PeerOutPackets;
168     lqr->LastOutOctets = HisLqrData.PeerOutOctets;
169     lqr->PeerInLQRs = HisLqrSave.SaveInLQRs;
170     lqr->PeerInPackets = HisLqrSave.SaveInPackets;
171     lqr->PeerInDiscards = HisLqrSave.SaveInDiscards;
172     lqr->PeerInErrors = HisLqrSave.SaveInErrors;
173     lqr->PeerInOctets = HisLqrSave.SaveInOctets;
174     lqr->PeerOutLQRs = ++ifOutLQRs;
175     LqrDump("LqrOutput", lqr);
176     LqrChangeOrder(lqr, (struct lqrdata *)(MBUF_CTOP(bp)));
177   }
178 
179   if (!DEV_IS_SYNC) {
180     fcs = HdlcFcs(INITFCS, MBUF_CTOP(mhp), mhp->cnt);
181     fcs = HdlcFcs(fcs, MBUF_CTOP(bp), bp->cnt);
182     fcs = ~fcs;
183     cp = MBUF_CTOP(mfcs);
184     *cp++ = fcs & 0377;	/* Low byte first!! */
185     *cp++ = fcs >> 8;
186   }
187 
188   LogDumpBp(LOG_HDLC, "HdlcOutput", mhp);
189   for (statp = ProtocolStat; statp->number; statp++)
190     if (statp->number == proto)
191       break;
192   statp->out_count++;
193   if (DEV_IS_SYNC)
194     ModemOutput(pri, mhp);
195   else
196     AsyncOutput(pri, mhp, proto);
197 }
198 
199 DecodePacket(proto, bp)
200 u_short proto;
201 struct mbuf *bp;
202 {
203 #ifdef DEBUG
204   logprintf("proto = %04x\n", proto);
205 #endif
206   switch (proto) {
207   case PROTO_LCP:
208     LcpInput(bp);
209     break;
210   case PROTO_PAP:
211     PapInput(bp);
212     break;
213   case PROTO_LQR:
214     HisLqrSave.SaveInLQRs++;
215     LqrInput(bp);
216     break;
217   case PROTO_CHAP:
218     ChapInput(bp);
219     break;
220   case PROTO_VJUNCOMP:
221   case PROTO_VJCOMP:
222     bp = VjCompInput(bp, proto);
223     if (bp == NULLBUFF) {
224       break;
225     }
226     /* fall down */
227   case PROTO_IP:
228     IpInput(bp);
229     break;
230   case PROTO_IPCP:
231     IpcpInput(bp);
232     break;
233   case PROTO_CCP:
234     CcpInput(bp);
235     break;
236   case PROTO_COMPD:
237     Pred1Input(bp);
238     break;
239   default:
240     logprintf("Unknown protocol 0x%04x\n", proto);
241     /*
242      * XXX: Should send protocol reject.
243      */
244     HisLqrSave.SaveInDiscards++;
245     HdlcStat.unknownproto++;
246     pfree(bp);
247     break;
248   }
249 }
250 
251 int
252 ReportProtStatus()
253 {
254   struct protostat *statp;
255   int cnt;
256 
257   statp = ProtocolStat;
258   statp--;
259   cnt = 0;
260   printf("    Protocol     in        out      Protocol      in       out\n");
261   do {
262     statp++;
263     printf("   %-9s: %8u, %8u",
264       statp->name, statp->in_count, statp->out_count);
265     if (++cnt == 2) {
266       printf("\n");
267       cnt = 0;
268     }
269   } while (statp->number);
270   if (cnt)
271      printf("\n");
272   return(1);
273 }
274 
275 int
276 ReportHdlcStatus()
277 {
278   struct hdlcstat *hp = &HdlcStat;
279 
280   printf("HDLC level errors\n\n");
281   printf("FCS: %u  ADDR: %u  COMMAND: %u  PROTO: %u\n",
282 	hp->badfcs, hp->badaddr, hp->badcommand, hp->unknownproto);
283   return(1);
284 }
285 
286 static struct hdlcstat laststat;
287 
288 void
289 HdlcErrorCheck()
290 {
291   struct hdlcstat *hp = &HdlcStat;
292   struct hdlcstat *op = &laststat;
293 
294   if (bcmp(hp, op, sizeof(laststat))) {
295     LogPrintf(LOG_PHASE, "HDLC errros -> FCS: %u ADDR: %u COMD: %u PROTO: %u\n",
296 	hp->badfcs - op->badfcs, hp->badaddr - op->badaddr,
297 	hp->badcommand - op->badcommand, hp->unknownproto - op->unknownproto);
298   }
299   laststat = HdlcStat;
300 }
301 
302 void
303 HdlcInput(struct mbuf *bp)
304 {
305   u_short fcs, proto;
306   u_char *cp, addr, ctrl;
307   struct protostat *statp;
308 
309   LogDumpBp(LOG_HDLC, "HdlcInput:", bp);
310   if (DEV_IS_SYNC)
311     fcs = GOODFCS;
312   else
313     fcs = HdlcFcs(INITFCS, MBUF_CTOP(bp), bp->cnt);
314   HisLqrSave.SaveInOctets += bp->cnt + 1;
315 
316 #ifdef DEBUG
317   logprintf("fcs = %04x (%s)\n", fcs, (fcs == GOODFCS)? "good" : "bad");
318 #endif
319   if (fcs != GOODFCS) {
320     HisLqrSave.SaveInErrors++;
321 #ifdef DEBUG
322     logprintf("Bad FCS\n");
323 #endif
324     HdlcStat.badfcs++;
325     pfree(bp);
326     return;
327   }
328   if (!DEV_IS_SYNC)
329     bp->cnt -= 2;		/* discard FCS part */
330   cp = MBUF_CTOP(bp);
331 
332   ifInPackets++;
333   ifInOctets += bp->cnt;
334 
335   if (!LcpInfo.want_acfcomp) {
336     /*
337      *  We expect that packet is not compressed.
338      */
339     addr = *cp++;
340     if (addr != HDLC_ADDR) {
341       HisLqrSave.SaveInErrors++;
342       HdlcStat.badaddr++;
343 #ifdef DEBUG
344       logprintf("addr %02x\n", *cp);
345 #endif
346       pfree(bp);
347       return;
348     }
349 
350     ctrl = *cp++;
351     if (ctrl != HDLC_UI) {
352       HisLqrSave.SaveInErrors++;
353       HdlcStat.badcommand++;
354 #ifdef DEBUG
355       logprintf("command %02x\n", *cp);
356 #endif
357       pfree(bp);
358       return;
359     }
360     bp->offset += 2;
361     bp->cnt -= 2;
362   } else if (cp[0] == HDLC_ADDR && cp[1] == HDLC_UI) {
363     /*
364      *  We can receive compressed packet, but peer still send
365      *  uncompressed packet to me.
366      */
367     cp += 2;
368     bp->offset += 2;
369     bp->cnt -= 2;
370   }
371 
372   if (LcpInfo.want_protocomp) {
373     proto = 0;
374     cp--;
375     do {
376       cp++; bp->offset++; bp->cnt--;
377       proto = proto << 8;
378       proto += *cp;
379     } while (!(proto & 1));
380   } else {
381     proto = *cp++ << 8;
382     proto |= *cp++;
383     bp->offset += 2;
384     bp->cnt -= 2;
385   }
386 
387   for (statp = ProtocolStat; statp->number; statp++)
388     if (statp->number == proto)
389       break;
390   statp->in_count++;
391   HisLqrSave.SaveInPackets++;
392 
393   DecodePacket(proto, bp);
394 }
395