xref: /freebsd/sys/netgraph/ng_lmi.c (revision a14a0223ae1b172e96dd2a1d849e22026a98b692)
1 
2 /*
3  * ng_lmi.c
4  *
5  * Copyright (c) 1996-1999 Whistle Communications, Inc.
6  * All rights reserved.
7  *
8  * Subject to the following obligations and disclaimer of warranty, use and
9  * redistribution of this software, in source or object code forms, with or
10  * without modifications are expressly permitted by Whistle Communications;
11  * provided, however, that:
12  * 1. Any and all reproductions of the source or object code must include the
13  *    copyright notice above and the following disclaimer of warranties; and
14  * 2. No rights are granted, in any manner or form, to use Whistle
15  *    Communications, Inc. trademarks, including the mark "WHISTLE
16  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
17  *    such appears in the above copyright notice or in the software.
18  *
19  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
20  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
21  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
22  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
23  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
24  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
25  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
26  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
27  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
28  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
29  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
30  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
31  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
35  * OF SUCH DAMAGE.
36  *
37  * Author: Julian Elischer <julian@whistle.com>
38  *
39  * $FreeBSD$
40  * $Whistle: ng_lmi.c,v 1.38 1999/11/01 09:24:52 julian Exp $
41  */
42 
43 /*
44  * This node performs the frame relay LMI protocol. It knows how
45  * to do ITU Annex A, ANSI Annex D, and "Group-of-Four" variants
46  * of the protocol.
47  *
48  * A specific protocol can be forced by connecting the corresponding
49  * hook to DLCI 0 or 1023 (as appropriate) of a frame relay link.
50  *
51  * Alternately, this node can do auto-detection of the LMI protocol
52  * by connecting hook "auto0" to DLCI 0 and "auto1023" to DLCI 1023.
53  */
54 
55 #include <sys/param.h>
56 #include <sys/systm.h>
57 #include <sys/errno.h>
58 #include <sys/kernel.h>
59 #include <sys/malloc.h>
60 #include <sys/mbuf.h>
61 #include <sys/syslog.h>
62 #include <netgraph/ng_message.h>
63 #include <netgraph/netgraph.h>
64 #include <netgraph/ng_lmi.h>
65 
66 /*
67  * Human readable names for LMI
68  */
69 #define NAME_ANNEXA	NG_LMI_HOOK_ANNEXA
70 #define NAME_ANNEXD	NG_LMI_HOOK_ANNEXD
71 #define NAME_GROUP4	NG_LMI_HOOK_GROUPOF4
72 #define NAME_NONE	"None"
73 
74 #define MAX_DLCIS	128
75 #define MAXDLCI		1023
76 
77 /*
78  * DLCI states
79  */
80 #define DLCI_NULL	0
81 #define DLCI_UP		1
82 #define DLCI_DOWN	2
83 
84 /*
85  * Any received LMI frame should be at least this long
86  */
87 #define LMI_MIN_LENGTH	8	/* XXX verify */
88 
89 /*
90  * Netgraph node methods and type descriptor
91  */
92 static ng_constructor_t	nglmi_constructor;
93 static ng_rcvmsg_t	nglmi_rcvmsg;
94 static ng_shutdown_t	nglmi_rmnode;
95 static ng_newhook_t	nglmi_newhook;
96 static ng_rcvdata_t	nglmi_rcvdata;
97 static ng_disconnect_t	nglmi_disconnect;
98 static int	nglmi_checkdata(hook_p hook, struct mbuf *m, meta_p meta);
99 
100 static struct ng_type typestruct = {
101 	NG_VERSION,
102 	NG_LMI_NODE_TYPE,
103 	NULL,
104 	nglmi_constructor,
105 	nglmi_rcvmsg,
106 	nglmi_rmnode,
107 	nglmi_newhook,
108 	NULL,
109 	NULL,
110 	nglmi_rcvdata,
111 	nglmi_rcvdata,
112 	nglmi_disconnect
113 };
114 NETGRAPH_INIT(lmi, &typestruct);
115 
116 /*
117  * Info and status per node
118  */
119 struct nglmi_softc {
120 	node_p  node;		/* netgraph node */
121 	int     flags;		/* state */
122 	int     poll_count;	/* the count of times for autolmi */
123 	int     poll_state;	/* state of auto detect machine */
124 	u_char  remote_seq;	/* sequence number the remote sent */
125 	u_char  local_seq;	/* last sequence number we sent */
126 	u_char  protoID;	/* 9 for group of 4, 8 otherwise */
127 	u_long  seq_retries;	/* sent this how many time so far */
128 	struct callout_handle handle;	/* see timeout(9) */
129 	int     liv_per_full;
130 	int     liv_rate;
131 	int     livs;
132 	int     need_full;
133 	hook_p  lmi_channel;	/* whatever we ended up using */
134 	hook_p  lmi_annexA;
135 	hook_p  lmi_annexD;
136 	hook_p  lmi_group4;
137 	hook_p  lmi_channel0;	/* auto-detect on DLCI 0 */
138 	hook_p  lmi_channel1023;/* auto-detect on DLCI 1023 */
139 	char   *protoname;	/* cache protocol name */
140 	u_char  dlci_state[MAXDLCI + 1];
141 	int     invalidx;	/* next dlci's to invalidate */
142 };
143 typedef struct nglmi_softc *sc_p;
144 
145 /*
146  * Other internal functions
147  */
148 static void	LMI_ticker(void *arg);
149 static void	nglmi_startup_fixed(sc_p sc, hook_p hook);
150 static void	nglmi_startup_auto(sc_p sc);
151 static void	nglmi_startup(sc_p sc);
152 static void	nglmi_inquire(sc_p sc, int full);
153 static void	ngauto_state_machine(sc_p sc);
154 
155 /*
156  * Values for 'flags' field
157  * NB: the SCF_CONNECTED flag is set if and only if the timer is running.
158  */
159 #define	SCF_CONNECTED	0x01	/* connected to something */
160 #define	SCF_AUTO	0x02	/* we are auto-detecting */
161 #define	SCF_FIXED	0x04	/* we are fixed from the start */
162 
163 #define	SCF_LMITYPE	0x18	/* mask for determining Annex mode */
164 #define	SCF_NOLMI	0x00	/* no LMI type selected yet */
165 #define	SCF_ANNEX_A	0x08	/* running annex A mode */
166 #define	SCF_ANNEX_D	0x10	/* running annex D mode */
167 #define	SCF_GROUP4	0x18	/* running group of 4 */
168 
169 #define SETLMITYPE(sc, annex)						\
170 do {									\
171 	(sc)->flags &= ~SCF_LMITYPE;					\
172 	(sc)->flags |= (annex);						\
173 } while (0)
174 
175 #define NOPROTO(sc) (((sc)->flags & SCF_LMITYPE) == SCF_NOLMI)
176 #define ANNEXA(sc) (((sc)->flags & SCF_LMITYPE) == SCF_ANNEX_A)
177 #define ANNEXD(sc) (((sc)->flags & SCF_LMITYPE) == SCF_ANNEX_D)
178 #define GROUP4(sc) (((sc)->flags & SCF_LMITYPE) == SCF_GROUP4)
179 
180 #define LMIPOLLSIZE	3
181 #define LMI_PATIENCE	8	/* declare all DLCI DOWN after N LMI failures */
182 
183 /*
184  * Node constructor
185  */
186 static int
187 nglmi_constructor(node_p *nodep)
188 {
189 	sc_p sc;
190 	int error = 0;
191 
192 	MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK);
193 	if (sc == NULL)
194 		return (ENOMEM);
195 	bzero(sc, sizeof(*sc));
196 
197 	callout_handle_init(&sc->handle);
198 	if ((error = ng_make_node_common(&typestruct, nodep))) {
199 		FREE(sc, M_NETGRAPH);
200 		return (error);
201 	}
202 	(*nodep)->private = sc;
203 	sc->protoname = NAME_NONE;
204 	sc->node = *nodep;
205 	sc->liv_per_full = NG_LMI_SEQ_PER_FULL;	/* make this dynamic */
206 	sc->liv_rate = NG_LMI_KEEPALIVE_RATE;
207 	return (0);
208 }
209 
210 /*
211  * The LMI channel has a private pointer which is the same as the
212  * node private pointer. The debug channel has a NULL private pointer.
213  */
214 static int
215 nglmi_newhook(node_p node, hook_p hook, const char *name)
216 {
217 	sc_p sc = node->private;
218 
219 	if (strcmp(name, NG_LMI_HOOK_DEBUG) == 0) {
220 		hook->private = NULL;
221 		return (0);
222 	}
223 	if (sc->flags & SCF_CONNECTED) {
224 		/* already connected, return an error */
225 		return (EINVAL);
226 	}
227 	if (strcmp(name, NG_LMI_HOOK_ANNEXA) == 0) {
228 		sc->lmi_annexA = hook;
229 		hook->private = node->private;
230 		sc->protoID = 8;
231 		SETLMITYPE(sc, SCF_ANNEX_A);
232 		sc->protoname = NAME_ANNEXA;
233 		nglmi_startup_fixed(sc, hook);
234 	} else if (strcmp(name, NG_LMI_HOOK_ANNEXD) == 0) {
235 		sc->lmi_annexD = hook;
236 		hook->private = node->private;
237 		sc->protoID = 8;
238 		SETLMITYPE(sc, SCF_ANNEX_D);
239 		sc->protoname = NAME_ANNEXD;
240 		nglmi_startup_fixed(sc, hook);
241 	} else if (strcmp(name, NG_LMI_HOOK_GROUPOF4) == 0) {
242 		sc->lmi_group4 = hook;
243 		hook->private = node->private;
244 		sc->protoID = 9;
245 		SETLMITYPE(sc, SCF_GROUP4);
246 		sc->protoname = NAME_GROUP4;
247 		nglmi_startup_fixed(sc, hook);
248 	} else if (strcmp(name, NG_LMI_HOOK_AUTO0) == 0) {
249 		/* Note this, and if B is already installed, we're complete */
250 		sc->lmi_channel0 = hook;
251 		sc->protoname = NAME_NONE;
252 		hook->private = node->private;
253 		if (sc->lmi_channel1023)
254 			nglmi_startup_auto(sc);
255 	} else if (strcmp(name, NG_LMI_HOOK_AUTO1023) == 0) {
256 		/* Note this, and if A is already installed, we're complete */
257 		sc->lmi_channel1023 = hook;
258 		sc->protoname = NAME_NONE;
259 		hook->private = node->private;
260 		if (sc->lmi_channel0)
261 			nglmi_startup_auto(sc);
262 	} else
263 		return (EINVAL);		/* unknown hook */
264 	return (0);
265 }
266 
267 /*
268  * We have just attached to a live (we hope) node.
269  * Fire out a LMI inquiry, and then start up the timers.
270  */
271 static void
272 LMI_ticker(void *arg)
273 {
274 	sc_p sc = arg;
275 	int s = splnet();
276 
277 	if (sc->flags & SCF_AUTO) {
278 		ngauto_state_machine(sc);
279 		sc->handle = timeout(LMI_ticker, sc, NG_LMI_POLL_RATE * hz);
280 	} else {
281 		if (sc->livs++ >= sc->liv_per_full) {
282 			nglmi_inquire(sc, 1);
283 			/* sc->livs = 0; *//* do this when we get the answer! */
284 		} else {
285 			nglmi_inquire(sc, 0);
286 		}
287 		sc->handle = timeout(LMI_ticker, sc, sc->liv_rate * hz);
288 	}
289 	splx(s);
290 }
291 
292 static void
293 nglmi_startup_fixed(sc_p sc, hook_p hook)
294 {
295 	sc->flags |= (SCF_FIXED | SCF_CONNECTED);
296 	sc->lmi_channel = hook;
297 	nglmi_startup(sc);
298 }
299 
300 static void
301 nglmi_startup_auto(sc_p sc)
302 {
303 	sc->flags |= (SCF_AUTO | SCF_CONNECTED);
304 	sc->poll_state = 0;	/* reset state machine */
305 	sc->poll_count = 0;
306 	nglmi_startup(sc);
307 }
308 
309 static void
310 nglmi_startup(sc_p sc)
311 {
312 	sc->remote_seq = 0;
313 	sc->local_seq = 1;
314 	sc->seq_retries = 0;
315 	sc->livs = sc->liv_per_full - 1;
316 	/* start off the ticker in 1 sec */
317 	sc->handle = timeout(LMI_ticker, sc, hz);
318 }
319 
320 #define META_PAD 16
321 static void
322 nglmi_inquire(sc_p sc, int full)
323 {
324 	struct mbuf *m;
325 	char   *cptr, *start;
326 	int     error;
327 	meta_p  meta = NULL;
328 
329 	if (sc->lmi_channel == NULL)
330 		return;
331 	MGETHDR(m, M_DONTWAIT, MT_DATA);
332 	if (m == NULL) {
333 		log(LOG_ERR, "nglmi: unable to start up LMI processing\n");
334 		return;
335 	}
336 	/* Allocate a meta struct (and leave some slop for options to be
337 	 * added by other modules). */
338 	/* MALLOC(meta, meta_p, sizeof( struct ng_meta) + META_PAD,
339 	 * M_NETGRAPH, M_NOWAIT); */
340 	MALLOC(meta, meta_p, sizeof(*meta) + META_PAD, M_NETGRAPH, M_NOWAIT);
341 	if (meta != NULL) {	/* if it failed, well, it was optional anyhow */
342 		meta->used_len = (u_short) sizeof(struct ng_meta);
343 		meta->allocated_len
344 		    = (u_short) sizeof(struct ng_meta) + META_PAD;
345 		meta->flags = 0;
346 		meta->priority = NG_LMI_LMI_PRIORITY;
347 		meta->discardability = -1;
348 	}
349 	m->m_data += 4;		/* leave some room for a header */
350 	cptr = start = mtod(m, char *);
351 	/* add in the header for an LMI inquiry. */
352 	*cptr++ = 0x03;		/* UI frame */
353 	if (GROUP4(sc))
354 		*cptr++ = 0x09;	/* proto discriminator */
355 	else
356 		*cptr++ = 0x08;	/* proto discriminator */
357 	*cptr++ = 0x00;		/* call reference */
358 	*cptr++ = 0x75;		/* inquiry */
359 
360 	/* If we are Annex-D, there is this extra thing.. */
361 	if (ANNEXD(sc))
362 		*cptr++ = 0x95;	/* ??? */
363 	/* Add a request type */
364 	if (ANNEXA(sc))
365 		*cptr++ = 0x51;	/* report type */
366 	else
367 		*cptr++ = 0x01;	/* report type */
368 	*cptr++ = 0x01;		/* size = 1 */
369 	if (full)
370 		*cptr++ = 0x00;	/* full */
371 	else
372 		*cptr++ = 0x01;	/* partial */
373 
374 	/* Add a link verification IE */
375 	if (ANNEXA(sc))
376 		*cptr++ = 0x53;	/* verification IE */
377 	else
378 		*cptr++ = 0x03;	/* verification IE */
379 	*cptr++ = 0x02;		/* 2 extra bytes */
380 	*cptr++ = sc->local_seq;
381 	*cptr++ = sc->remote_seq;
382 	sc->seq_retries++;
383 
384 	/* Send it */
385 	m->m_len = m->m_pkthdr.len = cptr - start;
386 	NG_SEND_DATA(error, sc->lmi_channel, m, meta);
387 
388 	/* If we've been sending requests for long enough, and there has
389 	 * been no response, then mark as DOWN, any DLCIs that are UP. */
390 	if (sc->seq_retries == LMI_PATIENCE) {
391 		int     count;
392 
393 		for (count = 0; count < MAXDLCI; count++)
394 			if (sc->dlci_state[count] == DLCI_UP)
395 				sc->dlci_state[count] = DLCI_DOWN;
396 	}
397 }
398 
399 /*
400  * State machine for LMI auto-detect. The transitions are ordered
401  * to try the more likely possibilities first.
402  */
403 static void
404 ngauto_state_machine(sc_p sc)
405 {
406 	if ((sc->poll_count <= 0) || (sc->poll_count > LMIPOLLSIZE)) {
407 		/* time to change states in the auto probe machine */
408 		/* capture wild values of poll_count while we are at it */
409 		sc->poll_count = LMIPOLLSIZE;
410 		sc->poll_state++;
411 	}
412 	switch (sc->poll_state) {
413 	case 7:
414 		log(LOG_WARNING, "nglmi: no response from exchange\n");
415 	default:		/* capture bad states */
416 		sc->poll_state = 1;
417 	case 1:
418 		sc->lmi_channel = sc->lmi_channel0;
419 		SETLMITYPE(sc, SCF_ANNEX_D);
420 		break;
421 	case 2:
422 		sc->lmi_channel = sc->lmi_channel1023;
423 		SETLMITYPE(sc, SCF_ANNEX_D);
424 		break;
425 	case 3:
426 		sc->lmi_channel = sc->lmi_channel0;
427 		SETLMITYPE(sc, SCF_ANNEX_A);
428 		break;
429 	case 4:
430 		sc->lmi_channel = sc->lmi_channel1023;
431 		SETLMITYPE(sc, SCF_GROUP4);
432 		break;
433 	case 5:
434 		sc->lmi_channel = sc->lmi_channel1023;
435 		SETLMITYPE(sc, SCF_ANNEX_A);
436 		break;
437 	case 6:
438 		sc->lmi_channel = sc->lmi_channel0;
439 		SETLMITYPE(sc, SCF_GROUP4);
440 		break;
441 	}
442 
443 	/* send an inquirey encoded appropriatly */
444 	nglmi_inquire(sc, 0);
445 	sc->poll_count--;
446 }
447 
448 /*
449  * Receive a netgraph control message.
450  */
451 static int
452 nglmi_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr,
453 	     struct ng_mesg **resp)
454 {
455 	int     error = 0;
456 	sc_p    sc = node->private;
457 
458 	switch (msg->header.typecookie) {
459 	case NGM_GENERIC_COOKIE:
460 		switch (msg->header.cmd) {
461 		case NGM_TEXT_STATUS:
462 		    {
463 			char   *arg;
464 			int     pos, count;
465 
466 			NG_MKRESPONSE(*resp, msg, NG_TEXTRESPONSE, M_NOWAIT);
467 			if (*resp == NULL) {
468 				error = ENOMEM;
469 				break;
470 			}
471 			arg = (*resp)->data;
472 			pos = sprintf(arg, "protocol %s ", sc->protoname);
473 			if (sc->flags & SCF_FIXED)
474 				pos += sprintf(arg + pos, "fixed\n");
475 			else if (sc->flags & SCF_AUTO)
476 				pos += sprintf(arg + pos, "auto-detecting\n");
477 			else
478 				pos += sprintf(arg + pos, "auto on dlci %d\n",
479 				    (sc->lmi_channel == sc->lmi_channel0) ?
480 				    0 : 1023);
481 			pos += sprintf(arg + pos,
482 			    "keepalive period: %d seconds\n", sc->liv_rate);
483 			pos += sprintf(arg + pos,
484 			    "unacknowledged keepalives: %ld\n",
485 			    sc->seq_retries);
486 			for (count = 0;
487 			     ((count <= MAXDLCI)
488 			      && (pos < (NG_TEXTRESPONSE - 20)));
489 			     count++) {
490 				if (sc->dlci_state[count]) {
491 					pos += sprintf(arg + pos,
492 					       "dlci %d %s\n", count,
493 					       (sc->dlci_state[count]
494 					== DLCI_UP) ? "up" : "down");
495 				}
496 			}
497 			(*resp)->header.arglen = pos + 1;
498 			break;
499 		    }
500 		default:
501 			error = EINVAL;
502 			break;
503 		}
504 		break;
505 	case NGM_LMI_COOKIE:
506 		switch (msg->header.cmd) {
507 		case NGM_LMI_GET_STATUS:
508 		    {
509 			struct nglmistat *stat;
510 			int k;
511 
512 			NG_MKRESPONSE(*resp, msg, sizeof(*stat), M_NOWAIT);
513 			if (!*resp) {
514 				error = ENOMEM;
515 				break;
516 			}
517 			stat = (struct nglmistat *) (*resp)->data;
518 			strncpy(stat->proto,
519 			     sc->protoname, sizeof(stat->proto) - 1);
520 			strncpy(stat->hook,
521 			      sc->protoname, sizeof(stat->hook) - 1);
522 			stat->autod = !!(sc->flags & SCF_AUTO);
523 			stat->fixed = !!(sc->flags & SCF_FIXED);
524 			for (k = 0; k <= MAXDLCI; k++) {
525 				switch (sc->dlci_state[k]) {
526 				case DLCI_UP:
527 					stat->up[k / 8] |= (1 << (k % 8));
528 					/* fall through */
529 				case DLCI_DOWN:
530 					stat->seen[k / 8] |= (1 << (k % 8));
531 					break;
532 				}
533 			}
534 			break;
535 		    }
536 		default:
537 			error = EINVAL;
538 			break;
539 		}
540 		break;
541 	default:
542 		error = EINVAL;
543 		break;
544 	}
545 	FREE(msg, M_NETGRAPH);
546 	return (error);
547 }
548 
549 #define STEPBY(stepsize)			\
550 	do {					\
551 		packetlen -= (stepsize);	\
552 		data += (stepsize);		\
553 	} while (0)
554 
555 /*
556  * receive data, and use it to update our status.
557  * Anything coming in on the debug port is discarded.
558  */
559 static int
560 nglmi_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
561 {
562 	sc_p    sc = hook->node->private;
563 	u_char *data;
564 	unsigned short dlci;
565 	u_short packetlen;
566 	int     resptype_seen = 0;
567 	int     seq_seen = 0;
568 
569 	if (hook->private == NULL) {
570 		goto drop;
571 	}
572 	packetlen = m->m_hdr.mh_len;
573 
574 	/* XXX what if it's more than 1 mbuf? */
575 	if ((packetlen > MHLEN) && !(m->m_flags & M_EXT)) {
576 		log(LOG_WARNING, "nglmi: packetlen (%d) too big\n", packetlen);
577 		goto drop;
578 	}
579 	if (m->m_len < packetlen && (m = m_pullup(m, packetlen)) == NULL) {
580 		log(LOG_WARNING,
581 		    "nglmi: m_pullup failed for %d bytes\n", packetlen);
582 		NG_FREE_META(meta);
583 		return (0);
584 	}
585 	if (nglmi_checkdata(hook, m, meta) == 0)
586 		return (0);
587 
588 	/* pass the first 4 bytes (already checked in the nglmi_checkdata()) */
589 	data = mtod(m, u_char *);
590 	STEPBY(4);
591 
592 	/* Now check if there is a 'locking shift'. This is only seen in
593 	 * Annex D frames. don't bother checking, we already did that. Don't
594 	 * increment immediatly as it might not be there. */
595 	if (ANNEXD(sc))
596 		STEPBY(1);
597 
598 	/* If we get this far we should consider that it is a legitimate
599 	 * frame and we know what it is. */
600 	if (sc->flags & SCF_AUTO) {
601 		/* note the hook that this valid channel came from and drop
602 		 * out of auto probe mode. */
603 		if (ANNEXA(sc))
604 			sc->protoname = NAME_ANNEXA;
605 		else if (ANNEXD(sc))
606 			sc->protoname = NAME_ANNEXD;
607 		else if (GROUP4(sc))
608 			sc->protoname = NAME_GROUP4;
609 		else {
610 			log(LOG_ERR, "nglmi: No known type\n");
611 			goto drop;
612 		}
613 		sc->lmi_channel = hook;
614 		sc->flags &= ~SCF_AUTO;
615 		log(LOG_INFO, "nglmi: auto-detected %s LMI on DLCI %d\n",
616 		    sc->protoname, hook == sc->lmi_channel0 ? 0 : 1023);
617 	}
618 
619 	/* While there is more data in the status packet, keep processing
620 	 * status items. First make sure there is enough data for the
621 	 * segment descriptor's length field. */
622 	while (packetlen >= 2) {
623 		u_int   segtype = data[0];
624 		u_int   segsize = data[1];
625 
626 		/* Now that we know how long it claims to be, make sure
627 		 * there is enough data for the next seg. */
628 		if (packetlen < segsize + 2)
629 			break;
630 		switch (segtype) {
631 		case 0x01:
632 		case 0x51:
633 			if (resptype_seen) {
634 				log(LOG_WARNING, "nglmi: dup MSGTYPE\n");
635 				goto nextIE;
636 			}
637 			resptype_seen++;
638 			/* The remote end tells us what kind of response
639 			 * this is. Only expect a type 0 or 1. if we are a
640 			 * full status, invalidate a few DLCIs just to see
641 			 * that they are still ok. */
642 			if (segsize != 1)
643 				goto nextIE;
644 			switch (data[2]) {
645 			case 1:
646 				/* partial status, do no extra processing */
647 				break;
648 			case 0:
649 			    {
650 				int     count = 0;
651 				int     idx = sc->invalidx;
652 
653 				for (count = 0; count < 10; count++) {
654 					if (idx > MAXDLCI)
655 						idx = 0;
656 					if (sc->dlci_state[idx] == DLCI_UP)
657 						sc->dlci_state[idx] = DLCI_DOWN;
658 					idx++;
659 				}
660 				sc->invalidx = idx;
661 				/* we got and we wanted one. relax
662 				 * now.. but don't reset to 0 if it
663 				 * was unrequested. */
664 				if (sc->livs > sc->liv_per_full)
665 					sc->livs = 0;
666 				break;
667 			    }
668 			}
669 			break;
670 		case 0x03:
671 		case 0x53:
672 			/* The remote tells us what it thinks the sequence
673 			 * numbers are. If it's not size 2, it must be a
674 			 * duplicate to have gotten this far, skip it. */
675 			if (seq_seen != 0)	/* already seen seq numbers */
676 				goto nextIE;
677 			if (segsize != 2)
678 				goto nextIE;
679 			sc->remote_seq = data[2];
680 			if (sc->local_seq == data[3]) {
681 				sc->local_seq++;
682 				sc->seq_retries = 0;
683 				/* Note that all 3 Frame protocols seem to
684 				 * not like 0 as a sequence number. */
685 				if (sc->local_seq == 0)
686 					sc->local_seq = 1;
687 			}
688 			break;
689 		case 0x07:
690 		case 0x57:
691 			/* The remote tells us about a DLCI that it knows
692 			 * about. There may be many of these in a single
693 			 * status response */
694 			switch (segsize) {
695 			case 6:/* only on 'group of 4' */
696 				dlci = ((u_short) data[2] & 0xff) << 8;
697 				dlci |= (data[3] & 0xff);
698 				if ((dlci < 1024) && (dlci > 0)) {
699 				  /* XXX */
700 				}
701 				break;
702 			case 3:
703 				dlci = ((u_short) data[2] & 0x3f) << 4;
704 				dlci |= ((data[3] & 0x78) >> 3);
705 				if ((dlci < 1024) && (dlci > 0)) {
706 					/* set up the bottom half of the
707 					 * support for that dlci if it's not
708 					 * already been done */
709 					/* store this information somewhere */
710 				}
711 				break;
712 			default:
713 				goto nextIE;
714 			}
715 			if (sc->dlci_state[dlci] != DLCI_UP) {
716 				/* bring new DLCI to life */
717 				/* may do more here some day */
718 				if (sc->dlci_state[dlci] != DLCI_DOWN)
719 					log(LOG_INFO,
720 					    "nglmi: DLCI %d became active\n",
721 					    dlci);
722 				sc->dlci_state[dlci] = DLCI_UP;
723 			}
724 			break;
725 		}
726 nextIE:
727 		STEPBY(segsize + 2);
728 	}
729 	NG_FREE_DATA(m, meta);
730 	return (0);
731 
732 drop:
733 	NG_FREE_DATA(m, meta);
734 	return (EINVAL);
735 }
736 
737 /*
738  * Check that a packet is entirely kosha.
739  * return 1 of ok, and 0 if not.
740  * All data is discarded if a 0 is returned.
741  */
742 static int
743 nglmi_checkdata(hook_p hook, struct mbuf *m, meta_p meta)
744 {
745 	sc_p    sc = hook->node->private;
746 	u_char *data;
747 	u_short packetlen;
748 	unsigned short dlci;
749 	u_char  type;
750 	u_char  nextbyte;
751 	int     seq_seen = 0;
752 	int     resptype_seen = 0;	/* 0 , 1 (partial) or 2 (full) */
753 	int     highest_dlci = 0;
754 
755 	packetlen = m->m_hdr.mh_len;
756 	data = mtod(m, u_char *);
757 	if (*data != 0x03) {
758 		log(LOG_WARNING, "nglmi: unexpected value in LMI(%d)\n", 1);
759 		goto reject;
760 	}
761 	STEPBY(1);
762 
763 	/* look at the protocol ID */
764 	nextbyte = *data;
765 	if (sc->flags & SCF_AUTO) {
766 		SETLMITYPE(sc, SCF_NOLMI);	/* start with a clean slate */
767 		switch (nextbyte) {
768 		case 0x8:
769 			sc->protoID = 8;
770 			break;
771 		case 0x9:
772 			SETLMITYPE(sc, SCF_GROUP4);
773 			sc->protoID = 9;
774 			break;
775 		default:
776 			log(LOG_WARNING, "nglmi: bad Protocol ID(%d)\n",
777 			    (int) nextbyte);
778 			goto reject;
779 		}
780 	} else {
781 		if (nextbyte != sc->protoID) {
782 			log(LOG_WARNING, "nglmi: unexpected Protocol ID(%d)\n",
783 			    (int) nextbyte);
784 			goto reject;
785 		}
786 	}
787 	STEPBY(1);
788 
789 	/* check call reference (always null in non ISDN frame relay) */
790 	if (*data != 0x00) {
791 		log(LOG_WARNING, "nglmi: unexpected Call Reference (0x%x)\n",
792 		    data[-1]);
793 		goto reject;
794 	}
795 	STEPBY(1);
796 
797 	/* check message type */
798 	switch ((type = *data)) {
799 	case 0x75:		/* Status enquiry */
800 		log(LOG_WARNING, "nglmi: unexpected message type(0x%x)\n",
801 		    data[-1]);
802 		goto reject;
803 	case 0x7D:		/* Status message */
804 		break;
805 	default:
806 		log(LOG_WARNING,
807 		    "nglmi: unexpected msg type(0x%x) \n", (int) type);
808 		goto reject;
809 	}
810 	STEPBY(1);
811 
812 	/* Now check if there is a 'locking shift'. This is only seen in
813 	 * Annex D frames. Don't increment immediately as it might not be
814 	 * there. */
815 	nextbyte = *data;
816 	if (sc->flags & SCF_AUTO) {
817 		if (!(GROUP4(sc))) {
818 			if (nextbyte == 0x95) {
819 				SETLMITYPE(sc, SCF_ANNEX_D);
820 				STEPBY(1);
821 			} else
822 				SETLMITYPE(sc, SCF_ANNEX_A);
823 		} else if (nextbyte == 0x95) {
824 			log(LOG_WARNING, "nglmi: locking shift seen in G4\n");
825 			goto reject;
826 		}
827 	} else {
828 		if (ANNEXD(sc)) {
829 			if (*data == 0x95)
830 				STEPBY(1);
831 			else {
832 				log(LOG_WARNING,
833 				    "nglmi: locking shift missing\n");
834 				goto reject;
835 			}
836 		} else if (*data == 0x95) {
837 			log(LOG_WARNING, "nglmi: locking shift seen\n");
838 			goto reject;
839 		}
840 	}
841 
842 	/* While there is more data in the status packet, keep processing
843 	 * status items. First make sure there is enough data for the
844 	 * segment descriptor's length field. */
845 	while (packetlen >= 2) {
846 		u_int   segtype = data[0];
847 		u_int   segsize = data[1];
848 
849 		/* Now that we know how long it claims to be, make sure
850 		 * there is enough data for the next seg. */
851 		if (packetlen < (segsize + 2)) {
852 			log(LOG_WARNING, "nglmi: IE longer than packet\n");
853 			break;
854 		}
855 		switch (segtype) {
856 		case 0x01:
857 		case 0x51:
858 			/* According to MCI's HP analyser, we should just
859 			 * ignore if there is mor ethan one of these (?). */
860 			if (resptype_seen) {
861 				log(LOG_WARNING, "nglmi: dup MSGTYPE\n");
862 				goto nextIE;
863 			}
864 			if (segsize != 1) {
865 				log(LOG_WARNING, "nglmi: MSGTYPE wrong size\n");
866 				goto reject;
867 			}
868 			/* The remote end tells us what kind of response
869 			 * this is. Only expect a type 0 or 1. if it was a
870 			 * full (type 0) check we just asked for a type
871 			 * full. */
872 			switch (data[2]) {
873 			case 1:/* partial */
874 				if (sc->livs > sc->liv_per_full) {
875 					log(LOG_WARNING,
876 					  "nglmi: LIV when FULL expected\n");
877 					goto reject;	/* need full */
878 				}
879 				resptype_seen = 1;
880 				break;
881 			case 0:/* full */
882 				/* Full response is always acceptable */
883 				resptype_seen = 2;
884 				break;
885 			default:
886 				log(LOG_WARNING,
887 				 "nglmi: Unknown report type %d\n", data[2]);
888 				goto reject;
889 			}
890 			break;
891 		case 0x03:
892 		case 0x53:
893 			/* The remote tells us what it thinks the sequence
894 			 * numbers are. I would have thought that there
895 			 * needs to be one and only one of these, but MCI
896 			 * want us to just ignore extras. (?) */
897 			if (resptype_seen == 0) {
898 				log(LOG_WARNING, "nglmi: no TYPE before SEQ\n");
899 				goto reject;
900 			}
901 			if (seq_seen != 0)	/* already seen seq numbers */
902 				goto nextIE;
903 			if (segsize != 2) {
904 				log(LOG_WARNING, "nglmi: bad SEQ sts size\n");
905 				goto reject;
906 			}
907 			if (sc->local_seq != data[3]) {
908 				log(LOG_WARNING, "nglmi: unexpected SEQ\n");
909 				goto reject;
910 			}
911 			seq_seen = 1;
912 			break;
913 		case 0x07:
914 		case 0x57:
915 			/* The remote tells us about a DLCI that it knows
916 			 * about. There may be many of these in a single
917 			 * status response */
918 			if (seq_seen != 1) {	/* already seen seq numbers? */
919 				log(LOG_WARNING,
920 				    "nglmi: No sequence before DLCI\n");
921 				goto reject;
922 			}
923 			if (resptype_seen != 2) {	/* must be full */
924 				log(LOG_WARNING,
925 				    "nglmi: No resp type before DLCI\n");
926 				goto reject;
927 			}
928 			if (GROUP4(sc)) {
929 				if (segsize != 6) {
930 					log(LOG_WARNING,
931 					    "nglmi: wrong IE segsize\n");
932 					goto reject;
933 				}
934 				dlci = ((u_short) data[2] & 0xff) << 8;
935 				dlci |= (data[3] & 0xff);
936 			} else {
937 				if (segsize != 3) {
938 					log(LOG_WARNING,
939 					    "nglmi: DLCI headersize of %d"
940 					    " not supported\n", segsize - 1);
941 					goto reject;
942 				}
943 				dlci = ((u_short) data[2] & 0x3f) << 4;
944 				dlci |= ((data[3] & 0x78) >> 3);
945 			}
946 			/* async can only have one of these */
947 #if 0				/* async not yet accepted */
948 			if (async && highest_dlci) {
949 				log(LOG_WARNING,
950 				    "nglmi: Async with > 1 DLCI\n");
951 				goto reject;
952 			}
953 #endif
954 			/* Annex D says these will always be Ascending, but
955 			 * the HP test for G4 says we should accept
956 			 * duplicates, so for now allow that. ( <= vs. < ) */
957 #if 0
958 			/* MCI tests want us to accept out of order for AnxD */
959 			if ((!GROUP4(sc)) && (dlci < highest_dlci)) {
960 				/* duplicate or mis-ordered dlci */
961 				/* (spec says they will increase in number) */
962 				log(LOG_WARNING, "nglmi: DLCI out of order\n");
963 				goto reject;
964 			}
965 #endif
966 			if (dlci > 1023) {
967 				log(LOG_WARNING, "nglmi: DLCI out of range\n");
968 				goto reject;
969 			}
970 			highest_dlci = dlci;
971 			break;
972 		default:
973 			log(LOG_WARNING,
974 			    "nglmi: unknown LMI segment type %d\n", segtype);
975 		}
976 nextIE:
977 		STEPBY(segsize + 2);
978 	}
979 	if (packetlen != 0) {	/* partial junk at end? */
980 		log(LOG_WARNING,
981 		    "nglmi: %d bytes extra at end of packet\n", packetlen);
982 		goto print;
983 	}
984 	if (resptype_seen == 0) {
985 		log(LOG_WARNING, "nglmi: No response type seen\n");
986 		goto reject;	/* had no response type */
987 	}
988 	if (seq_seen == 0) {
989 		log(LOG_WARNING, "nglmi: No sequence numbers seen\n");
990 		goto reject;	/* had no sequence numbers */
991 	}
992 	return (1);
993 
994 print:
995 	{
996 		int     i, j, k, pos;
997 		char    buf[100];
998 		int     loc;
999 		u_char *bp = mtod(m, u_char *);
1000 
1001 		k = i = 0;
1002 		loc = (m->m_hdr.mh_len - packetlen);
1003 		log(LOG_WARNING, "nglmi: error at location %d\n", loc);
1004 		while (k < m->m_hdr.mh_len) {
1005 			pos = 0;
1006 			j = 0;
1007 			while ((j++ < 16) && k < m->m_hdr.mh_len) {
1008 				pos += sprintf(buf + pos, "%c%02x",
1009 					       ((loc == k) ? '>' : ' '),
1010 					       bp[k]);
1011 				k++;
1012 			}
1013 			if (i == 0)
1014 				log(LOG_WARNING, "nglmi: packet data:%s\n", buf);
1015 			else
1016 				log(LOG_WARNING, "%04d              :%s\n", k, buf);
1017 			i++;
1018 		}
1019 	}
1020 	return (1);
1021 reject:
1022 	{
1023 		int     i, j, k, pos;
1024 		char    buf[100];
1025 		int     loc;
1026 		u_char *bp = mtod(m, u_char *);
1027 
1028 		k = i = 0;
1029 		loc = (m->m_hdr.mh_len - packetlen);
1030 		log(LOG_WARNING, "nglmi: error at location %d\n", loc);
1031 		while (k < m->m_hdr.mh_len) {
1032 			pos = 0;
1033 			j = 0;
1034 			while ((j++ < 16) && k < m->m_hdr.mh_len) {
1035 				pos += sprintf(buf + pos, "%c%02x",
1036 					       ((loc == k) ? '>' : ' '),
1037 					       bp[k]);
1038 				k++;
1039 			}
1040 			if (i == 0)
1041 				log(LOG_WARNING, "nglmi: packet data:%s\n", buf);
1042 			else
1043 				log(LOG_WARNING, "%04d              :%s\n", k, buf);
1044 			i++;
1045 		}
1046 	}
1047 	NG_FREE_DATA(m, meta);
1048 	return (0);
1049 }
1050 
1051 /*
1052  * Do local shutdown processing..
1053  * Cut any remaining links and free our local resources.
1054  */
1055 static int
1056 nglmi_rmnode(node_p node)
1057 {
1058 	const sc_p sc = node->private;
1059 
1060 	node->flags |= NG_INVALID;
1061 	ng_cutlinks(node);
1062 	ng_unname(node);
1063 	node->private = NULL;
1064 	ng_unref(sc->node);
1065 	FREE(sc, M_NETGRAPH);
1066 	return (0);
1067 }
1068 
1069 /*
1070  * Hook disconnection
1071  * For this type, removal of any link except "debug" destroys the node.
1072  */
1073 static int
1074 nglmi_disconnect(hook_p hook)
1075 {
1076 	const sc_p sc = hook->node->private;
1077 
1078 	/* OK to remove debug hook(s) */
1079 	if (hook->private == NULL)
1080 		return (0);
1081 
1082 	/* Stop timer if it's currently active */
1083 	if (sc->flags & SCF_CONNECTED)
1084 		untimeout(LMI_ticker, sc, sc->handle);
1085 
1086 	/* Self-destruct */
1087 	ng_rmnode(hook->node);
1088 	return (0);
1089 }
1090 
1091