xref: /freebsd/sys/netgraph/ng_lmi.c (revision 8fc257994d0ce2396196d7a06d50d20c8015f4b7)
1 /*
2  * ng_lmi.c
3  */
4 
5 /*-
6  * Copyright (c) 1996-1999 Whistle Communications, Inc.
7  * All rights reserved.
8  *
9  * Subject to the following obligations and disclaimer of warranty, use and
10  * redistribution of this software, in source or object code forms, with or
11  * without modifications are expressly permitted by Whistle Communications;
12  * provided, however, that:
13  * 1. Any and all reproductions of the source or object code must include the
14  *    copyright notice above and the following disclaimer of warranties; and
15  * 2. No rights are granted, in any manner or form, to use Whistle
16  *    Communications, Inc. trademarks, including the mark "WHISTLE
17  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
18  *    such appears in the above copyright notice or in the software.
19  *
20  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
21  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
22  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
23  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
25  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
26  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
27  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
28  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
29  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
30  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
31  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
32  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
36  * OF SUCH DAMAGE.
37  *
38  * Author: Julian Elischer <julian@freebsd.org>
39  *
40  * $FreeBSD$
41  * $Whistle: ng_lmi.c,v 1.38 1999/11/01 09:24:52 julian Exp $
42  */
43 
44 /*
45  * This node performs the frame relay LMI protocol. It knows how
46  * to do ITU Annex A, ANSI Annex D, and "Group-of-Four" variants
47  * of the protocol.
48  *
49  * A specific protocol can be forced by connecting the corresponding
50  * hook to DLCI 0 or 1023 (as appropriate) of a frame relay link.
51  *
52  * Alternately, this node can do auto-detection of the LMI protocol
53  * by connecting hook "auto0" to DLCI 0 and "auto1023" to DLCI 1023.
54  */
55 
56 #include <sys/param.h>
57 #include <sys/systm.h>
58 #include <sys/errno.h>
59 #include <sys/kernel.h>
60 #include <sys/malloc.h>
61 #include <sys/mbuf.h>
62 #include <sys/syslog.h>
63 #include <netgraph/ng_message.h>
64 #include <netgraph/netgraph.h>
65 #include <netgraph/ng_lmi.h>
66 
67 /*
68  * Human readable names for LMI
69  */
70 #define NAME_ANNEXA	NG_LMI_HOOK_ANNEXA
71 #define NAME_ANNEXD	NG_LMI_HOOK_ANNEXD
72 #define NAME_GROUP4	NG_LMI_HOOK_GROUPOF4
73 #define NAME_NONE	"None"
74 
75 #define MAX_DLCIS	128
76 #define MAXDLCI		1023
77 
78 /*
79  * DLCI states
80  */
81 #define DLCI_NULL	0
82 #define DLCI_UP		1
83 #define DLCI_DOWN	2
84 
85 /*
86  * Any received LMI frame should be at least this long
87  */
88 #define LMI_MIN_LENGTH	8	/* XXX verify */
89 
90 /*
91  * Netgraph node methods and type descriptor
92  */
93 static ng_constructor_t	nglmi_constructor;
94 static ng_rcvmsg_t	nglmi_rcvmsg;
95 static ng_shutdown_t	nglmi_shutdown;
96 static ng_newhook_t	nglmi_newhook;
97 static ng_rcvdata_t	nglmi_rcvdata;
98 static ng_disconnect_t	nglmi_disconnect;
99 static int	nglmi_checkdata(hook_p hook, struct mbuf *m);
100 
101 static struct ng_type typestruct = {
102 	.version =	NG_ABI_VERSION,
103 	.name =		NG_LMI_NODE_TYPE,
104 	.constructor =	nglmi_constructor,
105 	.rcvmsg	=	nglmi_rcvmsg,
106 	.shutdown =	nglmi_shutdown,
107 	.newhook =	nglmi_newhook,
108 	.rcvdata =	nglmi_rcvdata,
109 	.disconnect =	nglmi_disconnect,
110 };
111 NETGRAPH_INIT(lmi, &typestruct);
112 
113 /*
114  * Info and status per node
115  */
116 struct nglmi_softc {
117 	node_p  node;		/* netgraph node */
118 	int     flags;		/* state */
119 	int     poll_count;	/* the count of times for autolmi */
120 	int     poll_state;	/* state of auto detect machine */
121 	u_char  remote_seq;	/* sequence number the remote sent */
122 	u_char  local_seq;	/* last sequence number we sent */
123 	u_char  protoID;	/* 9 for group of 4, 8 otherwise */
124 	u_long  seq_retries;	/* sent this how many time so far */
125 	struct	callout	handle;	/* see timeout(9) */
126 	int     liv_per_full;
127 	int     liv_rate;
128 	int     livs;
129 	int     need_full;
130 	hook_p  lmi_channel;	/* whatever we ended up using */
131 	hook_p  lmi_annexA;
132 	hook_p  lmi_annexD;
133 	hook_p  lmi_group4;
134 	hook_p  lmi_channel0;	/* auto-detect on DLCI 0 */
135 	hook_p  lmi_channel1023;/* auto-detect on DLCI 1023 */
136 	char   *protoname;	/* cache protocol name */
137 	u_char  dlci_state[MAXDLCI + 1];
138 	int     invalidx;	/* next dlci's to invalidate */
139 };
140 typedef struct nglmi_softc *sc_p;
141 
142 /*
143  * Other internal functions
144  */
145 static void	LMI_ticker(node_p node, hook_p hook, void *arg1, int arg2);
146 static void	nglmi_startup_fixed(sc_p sc, hook_p hook);
147 static void	nglmi_startup_auto(sc_p sc);
148 static void	nglmi_startup(sc_p sc);
149 static void	nglmi_inquire(sc_p sc, int full);
150 static void	ngauto_state_machine(sc_p sc);
151 
152 /*
153  * Values for 'flags' field
154  * NB: the SCF_CONNECTED flag is set if and only if the timer is running.
155  */
156 #define	SCF_CONNECTED	0x01	/* connected to something */
157 #define	SCF_AUTO	0x02	/* we are auto-detecting */
158 #define	SCF_FIXED	0x04	/* we are fixed from the start */
159 
160 #define	SCF_LMITYPE	0x18	/* mask for determining Annex mode */
161 #define	SCF_NOLMI	0x00	/* no LMI type selected yet */
162 #define	SCF_ANNEX_A	0x08	/* running annex A mode */
163 #define	SCF_ANNEX_D	0x10	/* running annex D mode */
164 #define	SCF_GROUP4	0x18	/* running group of 4 */
165 
166 #define SETLMITYPE(sc, annex)						\
167 do {									\
168 	(sc)->flags &= ~SCF_LMITYPE;					\
169 	(sc)->flags |= (annex);						\
170 } while (0)
171 
172 #define NOPROTO(sc) (((sc)->flags & SCF_LMITYPE) == SCF_NOLMI)
173 #define ANNEXA(sc) (((sc)->flags & SCF_LMITYPE) == SCF_ANNEX_A)
174 #define ANNEXD(sc) (((sc)->flags & SCF_LMITYPE) == SCF_ANNEX_D)
175 #define GROUP4(sc) (((sc)->flags & SCF_LMITYPE) == SCF_GROUP4)
176 
177 #define LMIPOLLSIZE	3
178 #define LMI_PATIENCE	8	/* declare all DLCI DOWN after N LMI failures */
179 
180 /*
181  * Node constructor
182  */
183 static int
184 nglmi_constructor(node_p node)
185 {
186 	sc_p sc;
187 
188 	sc = malloc(sizeof(*sc), M_NETGRAPH, M_NOWAIT | M_ZERO);
189 	if (sc == NULL)
190 		return (ENOMEM);
191 
192 	NG_NODE_SET_PRIVATE(node, sc);
193 	sc->node = node;
194 
195 	ng_callout_init(&sc->handle);
196 	sc->protoname = NAME_NONE;
197 	sc->liv_per_full = NG_LMI_SEQ_PER_FULL;	/* make this dynamic */
198 	sc->liv_rate = NG_LMI_KEEPALIVE_RATE;
199 	return (0);
200 }
201 
202 /*
203  * The LMI channel has a private pointer which is the same as the
204  * node private pointer. The debug channel has a NULL private pointer.
205  */
206 static int
207 nglmi_newhook(node_p node, hook_p hook, const char *name)
208 {
209 	sc_p sc = NG_NODE_PRIVATE(node);
210 
211 	if (strcmp(name, NG_LMI_HOOK_DEBUG) == 0) {
212 		NG_HOOK_SET_PRIVATE(hook, NULL);
213 		return (0);
214 	}
215 	if (sc->flags & SCF_CONNECTED) {
216 		/* already connected, return an error */
217 		return (EINVAL);
218 	}
219 	if (strcmp(name, NG_LMI_HOOK_ANNEXA) == 0) {
220 		sc->lmi_annexA = hook;
221 		NG_HOOK_SET_PRIVATE(hook, NG_NODE_PRIVATE(node));
222 		sc->protoID = 8;
223 		SETLMITYPE(sc, SCF_ANNEX_A);
224 		sc->protoname = NAME_ANNEXA;
225 		nglmi_startup_fixed(sc, hook);
226 	} else if (strcmp(name, NG_LMI_HOOK_ANNEXD) == 0) {
227 		sc->lmi_annexD = hook;
228 		NG_HOOK_SET_PRIVATE(hook, NG_NODE_PRIVATE(node));
229 		sc->protoID = 8;
230 		SETLMITYPE(sc, SCF_ANNEX_D);
231 		sc->protoname = NAME_ANNEXD;
232 		nglmi_startup_fixed(sc, hook);
233 	} else if (strcmp(name, NG_LMI_HOOK_GROUPOF4) == 0) {
234 		sc->lmi_group4 = hook;
235 		NG_HOOK_SET_PRIVATE(hook, NG_NODE_PRIVATE(node));
236 		sc->protoID = 9;
237 		SETLMITYPE(sc, SCF_GROUP4);
238 		sc->protoname = NAME_GROUP4;
239 		nglmi_startup_fixed(sc, hook);
240 	} else if (strcmp(name, NG_LMI_HOOK_AUTO0) == 0) {
241 		/* Note this, and if B is already installed, we're complete */
242 		sc->lmi_channel0 = hook;
243 		sc->protoname = NAME_NONE;
244 		NG_HOOK_SET_PRIVATE(hook, NG_NODE_PRIVATE(node));
245 		if (sc->lmi_channel1023)
246 			nglmi_startup_auto(sc);
247 	} else if (strcmp(name, NG_LMI_HOOK_AUTO1023) == 0) {
248 		/* Note this, and if A is already installed, we're complete */
249 		sc->lmi_channel1023 = hook;
250 		sc->protoname = NAME_NONE;
251 		NG_HOOK_SET_PRIVATE(hook, NG_NODE_PRIVATE(node));
252 		if (sc->lmi_channel0)
253 			nglmi_startup_auto(sc);
254 	} else
255 		return (EINVAL);		/* unknown hook */
256 	return (0);
257 }
258 
259 /*
260  * We have just attached to a live (we hope) node.
261  * Fire out a LMI inquiry, and then start up the timers.
262  */
263 static void
264 LMI_ticker(node_p node, hook_p hook, void *arg1, int arg2)
265 {
266 	sc_p sc = NG_NODE_PRIVATE(node);
267 
268 	if (sc->flags & SCF_AUTO) {
269 		ngauto_state_machine(sc);
270 		ng_callout(&sc->handle, node, NULL, NG_LMI_POLL_RATE * hz,
271 		    LMI_ticker, NULL, 0);
272 	} else {
273 		if (sc->livs++ >= sc->liv_per_full) {
274 			nglmi_inquire(sc, 1);
275 			/* sc->livs = 0; *//* do this when we get the answer! */
276 		} else {
277 			nglmi_inquire(sc, 0);
278 		}
279 		ng_callout(&sc->handle, node, NULL, sc->liv_rate * hz,
280 		    LMI_ticker, NULL, 0);
281 	}
282 }
283 
284 static void
285 nglmi_startup_fixed(sc_p sc, hook_p hook)
286 {
287 	sc->flags |= (SCF_FIXED | SCF_CONNECTED);
288 	sc->lmi_channel = hook;
289 	nglmi_startup(sc);
290 }
291 
292 static void
293 nglmi_startup_auto(sc_p sc)
294 {
295 	sc->flags |= (SCF_AUTO | SCF_CONNECTED);
296 	sc->poll_state = 0;	/* reset state machine */
297 	sc->poll_count = 0;
298 	nglmi_startup(sc);
299 }
300 
301 static void
302 nglmi_startup(sc_p sc)
303 {
304 	sc->remote_seq = 0;
305 	sc->local_seq = 1;
306 	sc->seq_retries = 0;
307 	sc->livs = sc->liv_per_full - 1;
308 	/* start off the ticker in 1 sec */
309 	ng_callout(&sc->handle, sc->node, NULL, hz, LMI_ticker, NULL, 0);
310 }
311 
312 static void
313 nglmi_inquire(sc_p sc, int full)
314 {
315 	struct mbuf *m;
316 	struct ng_tag_prio *ptag;
317 	char   *cptr, *start;
318 	int     error;
319 
320 	if (sc->lmi_channel == NULL)
321 		return;
322 	MGETHDR(m, M_DONTWAIT, MT_DATA);
323 	if (m == NULL) {
324 		log(LOG_ERR, "nglmi: unable to start up LMI processing\n");
325 		return;
326 	}
327 	m->m_pkthdr.rcvif = NULL;
328 
329 	/* Attach a tag to packet, marking it of link level state priority, so
330 	 * that device driver would put it in the beginning of queue */
331 
332 	ptag = (struct ng_tag_prio *)m_tag_alloc(NGM_GENERIC_COOKIE, NG_TAG_PRIO,
333 	    (sizeof(struct ng_tag_prio) - sizeof(struct m_tag)), M_NOWAIT);
334 	if (ptag != NULL) {	/* if it failed, well, it was optional anyhow */
335 		ptag->priority = NG_PRIO_LINKSTATE;
336 		ptag->discardability = -1;
337 		m_tag_prepend(m, &ptag->tag);
338 	}
339 
340 	m->m_data += 4;		/* leave some room for a header */
341 	cptr = start = mtod(m, char *);
342 	/* add in the header for an LMI inquiry. */
343 	*cptr++ = 0x03;		/* UI frame */
344 	if (GROUP4(sc))
345 		*cptr++ = 0x09;	/* proto discriminator */
346 	else
347 		*cptr++ = 0x08;	/* proto discriminator */
348 	*cptr++ = 0x00;		/* call reference */
349 	*cptr++ = 0x75;		/* inquiry */
350 
351 	/* If we are Annex-D, add locking shift to codeset 5. */
352 	if (ANNEXD(sc))
353 		*cptr++ = 0x95;	/* locking shift */
354 	/* Add a request type */
355 	if (ANNEXA(sc))
356 		*cptr++ = 0x51;	/* report type */
357 	else
358 		*cptr++ = 0x01;	/* report type */
359 	*cptr++ = 0x01;		/* size = 1 */
360 	if (full)
361 		*cptr++ = 0x00;	/* full */
362 	else
363 		*cptr++ = 0x01;	/* partial */
364 
365 	/* Add a link verification IE */
366 	if (ANNEXA(sc))
367 		*cptr++ = 0x53;	/* verification IE */
368 	else
369 		*cptr++ = 0x03;	/* verification IE */
370 	*cptr++ = 0x02;		/* 2 extra bytes */
371 	*cptr++ = sc->local_seq;
372 	*cptr++ = sc->remote_seq;
373 	sc->seq_retries++;
374 
375 	/* Send it */
376 	m->m_len = m->m_pkthdr.len = cptr - start;
377 	NG_SEND_DATA_ONLY(error, sc->lmi_channel, m);
378 
379 	/* If we've been sending requests for long enough, and there has
380 	 * been no response, then mark as DOWN, any DLCIs that are UP. */
381 	if (sc->seq_retries == LMI_PATIENCE) {
382 		int     count;
383 
384 		for (count = 0; count < MAXDLCI; count++)
385 			if (sc->dlci_state[count] == DLCI_UP)
386 				sc->dlci_state[count] = DLCI_DOWN;
387 	}
388 }
389 
390 /*
391  * State machine for LMI auto-detect. The transitions are ordered
392  * to try the more likely possibilities first.
393  */
394 static void
395 ngauto_state_machine(sc_p sc)
396 {
397 	if ((sc->poll_count <= 0) || (sc->poll_count > LMIPOLLSIZE)) {
398 		/* time to change states in the auto probe machine */
399 		/* capture wild values of poll_count while we are at it */
400 		sc->poll_count = LMIPOLLSIZE;
401 		sc->poll_state++;
402 	}
403 	switch (sc->poll_state) {
404 	case 7:
405 		log(LOG_WARNING, "nglmi: no response from exchange\n");
406 	default:		/* capture bad states */
407 		sc->poll_state = 1;
408 	case 1:
409 		sc->lmi_channel = sc->lmi_channel0;
410 		SETLMITYPE(sc, SCF_ANNEX_D);
411 		break;
412 	case 2:
413 		sc->lmi_channel = sc->lmi_channel1023;
414 		SETLMITYPE(sc, SCF_ANNEX_D);
415 		break;
416 	case 3:
417 		sc->lmi_channel = sc->lmi_channel0;
418 		SETLMITYPE(sc, SCF_ANNEX_A);
419 		break;
420 	case 4:
421 		sc->lmi_channel = sc->lmi_channel1023;
422 		SETLMITYPE(sc, SCF_GROUP4);
423 		break;
424 	case 5:
425 		sc->lmi_channel = sc->lmi_channel1023;
426 		SETLMITYPE(sc, SCF_ANNEX_A);
427 		break;
428 	case 6:
429 		sc->lmi_channel = sc->lmi_channel0;
430 		SETLMITYPE(sc, SCF_GROUP4);
431 		break;
432 	}
433 
434 	/* send an inquirey encoded appropriatly */
435 	nglmi_inquire(sc, 0);
436 	sc->poll_count--;
437 }
438 
439 /*
440  * Receive a netgraph control message.
441  */
442 static int
443 nglmi_rcvmsg(node_p node, item_p item, hook_p lasthook)
444 {
445 	sc_p    sc = NG_NODE_PRIVATE(node);
446 	struct ng_mesg *resp = NULL;
447 	int     error = 0;
448 	struct ng_mesg *msg;
449 
450 	NGI_GET_MSG(item, msg);
451 	switch (msg->header.typecookie) {
452 	case NGM_GENERIC_COOKIE:
453 		switch (msg->header.cmd) {
454 		case NGM_TEXT_STATUS:
455 		    {
456 			char   *arg;
457 			int     pos, count;
458 
459 			NG_MKRESPONSE(resp, msg, NG_TEXTRESPONSE, M_NOWAIT);
460 			if (resp == NULL) {
461 				error = ENOMEM;
462 				break;
463 			}
464 			arg = resp->data;
465 			pos = sprintf(arg, "protocol %s ", sc->protoname);
466 			if (sc->flags & SCF_FIXED)
467 				pos += sprintf(arg + pos, "fixed\n");
468 			else if (sc->flags & SCF_AUTO)
469 				pos += sprintf(arg + pos, "auto-detecting\n");
470 			else
471 				pos += sprintf(arg + pos, "auto on dlci %d\n",
472 				    (sc->lmi_channel == sc->lmi_channel0) ?
473 				    0 : 1023);
474 			pos += sprintf(arg + pos,
475 			    "keepalive period: %d seconds\n", sc->liv_rate);
476 			pos += sprintf(arg + pos,
477 			    "unacknowledged keepalives: %ld\n",
478 			    sc->seq_retries);
479 			for (count = 0;
480 			     ((count <= MAXDLCI)
481 			      && (pos < (NG_TEXTRESPONSE - 20)));
482 			     count++) {
483 				if (sc->dlci_state[count]) {
484 					pos += sprintf(arg + pos,
485 					       "dlci %d %s\n", count,
486 					       (sc->dlci_state[count]
487 					== DLCI_UP) ? "up" : "down");
488 				}
489 			}
490 			resp->header.arglen = pos + 1;
491 			break;
492 		    }
493 		default:
494 			error = EINVAL;
495 			break;
496 		}
497 		break;
498 	case NGM_LMI_COOKIE:
499 		switch (msg->header.cmd) {
500 		case NGM_LMI_GET_STATUS:
501 		    {
502 			struct nglmistat *stat;
503 			int k;
504 
505 			NG_MKRESPONSE(resp, msg, sizeof(*stat), M_NOWAIT);
506 			if (!resp) {
507 				error = ENOMEM;
508 				break;
509 			}
510 			stat = (struct nglmistat *) resp->data;
511 			strncpy(stat->proto,
512 			     sc->protoname, sizeof(stat->proto) - 1);
513 			strncpy(stat->hook,
514 			      sc->protoname, sizeof(stat->hook) - 1);
515 			stat->autod = !!(sc->flags & SCF_AUTO);
516 			stat->fixed = !!(sc->flags & SCF_FIXED);
517 			for (k = 0; k <= MAXDLCI; k++) {
518 				switch (sc->dlci_state[k]) {
519 				case DLCI_UP:
520 					stat->up[k / 8] |= (1 << (k % 8));
521 					/* fall through */
522 				case DLCI_DOWN:
523 					stat->seen[k / 8] |= (1 << (k % 8));
524 					break;
525 				}
526 			}
527 			break;
528 		    }
529 		default:
530 			error = EINVAL;
531 			break;
532 		}
533 		break;
534 	default:
535 		error = EINVAL;
536 		break;
537 	}
538 
539 	NG_RESPOND_MSG(error, node, item, resp);
540 	NG_FREE_MSG(msg);
541 	return (error);
542 }
543 
544 #define STEPBY(stepsize)			\
545 	do {					\
546 		packetlen -= (stepsize);	\
547 		data += (stepsize);		\
548 	} while (0)
549 
550 /*
551  * receive data, and use it to update our status.
552  * Anything coming in on the debug port is discarded.
553  */
554 static int
555 nglmi_rcvdata(hook_p hook, item_p item)
556 {
557 	sc_p    sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
558 	const	u_char *data;
559 	unsigned short dlci;
560 	u_short packetlen;
561 	int     resptype_seen = 0;
562 	struct mbuf *m;
563 
564 	NGI_GET_M(item, m);
565 	NG_FREE_ITEM(item);
566 	if (NG_HOOK_PRIVATE(hook) == NULL) {
567 		goto drop;
568 	}
569 	packetlen = m->m_len;
570 
571 	/* XXX what if it's more than 1 mbuf? */
572 	if ((packetlen > MHLEN) && !(m->m_flags & M_EXT)) {
573 		log(LOG_WARNING, "nglmi: packetlen (%d) too big\n", packetlen);
574 		goto drop;
575 	}
576 	if (m->m_len < packetlen && (m = m_pullup(m, packetlen)) == NULL) {
577 		log(LOG_WARNING,
578 		    "nglmi: m_pullup failed for %d bytes\n", packetlen);
579 		return (0);
580 	}
581 	if (nglmi_checkdata(hook, m) == 0)
582 		return (0);
583 
584 	/* pass the first 4 bytes (already checked in the nglmi_checkdata()) */
585 	data = mtod(m, const u_char *);
586 	STEPBY(4);
587 
588 	/* Now check if there is a 'locking shift'. This is only seen in
589 	 * Annex D frames. don't bother checking, we already did that. Don't
590 	 * increment immediatly as it might not be there. */
591 	if (ANNEXD(sc))
592 		STEPBY(1);
593 
594 	/* If we get this far we should consider that it is a legitimate
595 	 * frame and we know what it is. */
596 	if (sc->flags & SCF_AUTO) {
597 		/* note the hook that this valid channel came from and drop
598 		 * out of auto probe mode. */
599 		if (ANNEXA(sc))
600 			sc->protoname = NAME_ANNEXA;
601 		else if (ANNEXD(sc))
602 			sc->protoname = NAME_ANNEXD;
603 		else if (GROUP4(sc))
604 			sc->protoname = NAME_GROUP4;
605 		else {
606 			log(LOG_ERR, "nglmi: No known type\n");
607 			goto drop;
608 		}
609 		sc->lmi_channel = hook;
610 		sc->flags &= ~SCF_AUTO;
611 		log(LOG_INFO, "nglmi: auto-detected %s LMI on DLCI %d\n",
612 		    sc->protoname, hook == sc->lmi_channel0 ? 0 : 1023);
613 	}
614 
615 	/* While there is more data in the status packet, keep processing
616 	 * status items. First make sure there is enough data for the
617 	 * segment descriptor's length field. */
618 	while (packetlen >= 2) {
619 		u_int   segtype = data[0];
620 		u_int   segsize = data[1];
621 
622 		/* Now that we know how long it claims to be, make sure
623 		 * there is enough data for the next seg. */
624 		if (packetlen < segsize + 2)
625 			break;
626 		switch (segtype) {
627 		case 0x01:
628 		case 0x51:
629 			if (resptype_seen) {
630 				log(LOG_WARNING, "nglmi: dup MSGTYPE\n");
631 				goto nextIE;
632 			}
633 			resptype_seen++;
634 			/* The remote end tells us what kind of response
635 			 * this is. Only expect a type 0 or 1. if we are a
636 			 * full status, invalidate a few DLCIs just to see
637 			 * that they are still ok. */
638 			if (segsize != 1)
639 				goto nextIE;
640 			switch (data[2]) {
641 			case 1:
642 				/* partial status, do no extra processing */
643 				break;
644 			case 0:
645 			    {
646 				int     count = 0;
647 				int     idx = sc->invalidx;
648 
649 				for (count = 0; count < 10; count++) {
650 					if (idx > MAXDLCI)
651 						idx = 0;
652 					if (sc->dlci_state[idx] == DLCI_UP)
653 						sc->dlci_state[idx] = DLCI_DOWN;
654 					idx++;
655 				}
656 				sc->invalidx = idx;
657 				/* we got and we wanted one. relax
658 				 * now.. but don't reset to 0 if it
659 				 * was unrequested. */
660 				if (sc->livs > sc->liv_per_full)
661 					sc->livs = 0;
662 				break;
663 			    }
664 			}
665 			break;
666 		case 0x03:
667 		case 0x53:
668 			/* The remote tells us what it thinks the sequence
669 			 * numbers are. If it's not size 2, it must be a
670 			 * duplicate to have gotten this far, skip it. */
671 			if (segsize != 2)
672 				goto nextIE;
673 			sc->remote_seq = data[2];
674 			if (sc->local_seq == data[3]) {
675 				sc->local_seq++;
676 				sc->seq_retries = 0;
677 				/* Note that all 3 Frame protocols seem to
678 				 * not like 0 as a sequence number. */
679 				if (sc->local_seq == 0)
680 					sc->local_seq = 1;
681 			}
682 			break;
683 		case 0x07:
684 		case 0x57:
685 			/* The remote tells us about a DLCI that it knows
686 			 * about. There may be many of these in a single
687 			 * status response */
688 			switch (segsize) {
689 			case 6:/* only on 'group of 4' */
690 				dlci = ((u_short) data[2] & 0xff) << 8;
691 				dlci |= (data[3] & 0xff);
692 				if ((dlci < 1024) && (dlci > 0)) {
693 				  /* XXX */
694 				}
695 				break;
696 			case 3:
697 				dlci = ((u_short) data[2] & 0x3f) << 4;
698 				dlci |= ((data[3] & 0x78) >> 3);
699 				if ((dlci < 1024) && (dlci > 0)) {
700 					/* set up the bottom half of the
701 					 * support for that dlci if it's not
702 					 * already been done */
703 					/* store this information somewhere */
704 				}
705 				break;
706 			default:
707 				goto nextIE;
708 			}
709 			if (sc->dlci_state[dlci] != DLCI_UP) {
710 				/* bring new DLCI to life */
711 				/* may do more here some day */
712 				if (sc->dlci_state[dlci] != DLCI_DOWN)
713 					log(LOG_INFO,
714 					    "nglmi: DLCI %d became active\n",
715 					    dlci);
716 				sc->dlci_state[dlci] = DLCI_UP;
717 			}
718 			break;
719 		}
720 nextIE:
721 		STEPBY(segsize + 2);
722 	}
723 	NG_FREE_M(m);
724 	return (0);
725 
726 drop:
727 	NG_FREE_M(m);
728 	return (EINVAL);
729 }
730 
731 /*
732  * Check that a packet is entirely kosha.
733  * return 1 of ok, and 0 if not.
734  * All data is discarded if a 0 is returned.
735  */
736 static int
737 nglmi_checkdata(hook_p hook, struct mbuf *m)
738 {
739 	sc_p    sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
740 	const	u_char *data;
741 	u_short packetlen;
742 	unsigned short dlci;
743 	u_char  type;
744 	u_char  nextbyte;
745 	int     seq_seen = 0;
746 	int     resptype_seen = 0;	/* 0 , 1 (partial) or 2 (full) */
747 	int     highest_dlci = 0;
748 
749 	packetlen = m->m_len;
750 	data = mtod(m, const u_char *);
751 	if (*data != 0x03) {
752 		log(LOG_WARNING, "nglmi: unexpected value in LMI(%d)\n", 1);
753 		goto reject;
754 	}
755 	STEPBY(1);
756 
757 	/* look at the protocol ID */
758 	nextbyte = *data;
759 	if (sc->flags & SCF_AUTO) {
760 		SETLMITYPE(sc, SCF_NOLMI);	/* start with a clean slate */
761 		switch (nextbyte) {
762 		case 0x8:
763 			sc->protoID = 8;
764 			break;
765 		case 0x9:
766 			SETLMITYPE(sc, SCF_GROUP4);
767 			sc->protoID = 9;
768 			break;
769 		default:
770 			log(LOG_WARNING, "nglmi: bad Protocol ID(%d)\n",
771 			    (int) nextbyte);
772 			goto reject;
773 		}
774 	} else {
775 		if (nextbyte != sc->protoID) {
776 			log(LOG_WARNING, "nglmi: unexpected Protocol ID(%d)\n",
777 			    (int) nextbyte);
778 			goto reject;
779 		}
780 	}
781 	STEPBY(1);
782 
783 	/* check call reference (always null in non ISDN frame relay) */
784 	if (*data != 0x00) {
785 		log(LOG_WARNING, "nglmi: unexpected Call Reference (0x%x)\n",
786 		    data[-1]);
787 		goto reject;
788 	}
789 	STEPBY(1);
790 
791 	/* check message type */
792 	switch ((type = *data)) {
793 	case 0x75:		/* Status enquiry */
794 		log(LOG_WARNING, "nglmi: unexpected message type(0x%x)\n",
795 		    data[-1]);
796 		goto reject;
797 	case 0x7D:		/* Status message */
798 		break;
799 	default:
800 		log(LOG_WARNING,
801 		    "nglmi: unexpected msg type(0x%x) \n", (int) type);
802 		goto reject;
803 	}
804 	STEPBY(1);
805 
806 	/* Now check if there is a 'locking shift'. This is only seen in
807 	 * Annex D frames. Don't increment immediately as it might not be
808 	 * there. */
809 	nextbyte = *data;
810 	if (sc->flags & SCF_AUTO) {
811 		if (!(GROUP4(sc))) {
812 			if (nextbyte == 0x95) {
813 				SETLMITYPE(sc, SCF_ANNEX_D);
814 				STEPBY(1);
815 			} else
816 				SETLMITYPE(sc, SCF_ANNEX_A);
817 		} else if (nextbyte == 0x95) {
818 			log(LOG_WARNING, "nglmi: locking shift seen in G4\n");
819 			goto reject;
820 		}
821 	} else {
822 		if (ANNEXD(sc)) {
823 			if (*data == 0x95)
824 				STEPBY(1);
825 			else {
826 				log(LOG_WARNING,
827 				    "nglmi: locking shift missing\n");
828 				goto reject;
829 			}
830 		} else if (*data == 0x95) {
831 			log(LOG_WARNING, "nglmi: locking shift seen\n");
832 			goto reject;
833 		}
834 	}
835 
836 	/* While there is more data in the status packet, keep processing
837 	 * status items. First make sure there is enough data for the
838 	 * segment descriptor's length field. */
839 	while (packetlen >= 2) {
840 		u_int   segtype = data[0];
841 		u_int   segsize = data[1];
842 
843 		/* Now that we know how long it claims to be, make sure
844 		 * there is enough data for the next seg. */
845 		if (packetlen < (segsize + 2)) {
846 			log(LOG_WARNING, "nglmi: IE longer than packet\n");
847 			break;
848 		}
849 		switch (segtype) {
850 		case 0x01:
851 		case 0x51:
852 			/* According to MCI's HP analyser, we should just
853 			 * ignore if there is mor ethan one of these (?). */
854 			if (resptype_seen) {
855 				log(LOG_WARNING, "nglmi: dup MSGTYPE\n");
856 				goto nextIE;
857 			}
858 			if (segsize != 1) {
859 				log(LOG_WARNING, "nglmi: MSGTYPE wrong size\n");
860 				goto reject;
861 			}
862 			/* The remote end tells us what kind of response
863 			 * this is. Only expect a type 0 or 1. if it was a
864 			 * full (type 0) check we just asked for a type
865 			 * full. */
866 			switch (data[2]) {
867 			case 1:/* partial */
868 				if (sc->livs > sc->liv_per_full) {
869 					log(LOG_WARNING,
870 					  "nglmi: LIV when FULL expected\n");
871 					goto reject;	/* need full */
872 				}
873 				resptype_seen = 1;
874 				break;
875 			case 0:/* full */
876 				/* Full response is always acceptable */
877 				resptype_seen = 2;
878 				break;
879 			default:
880 				log(LOG_WARNING,
881 				 "nglmi: Unknown report type %d\n", data[2]);
882 				goto reject;
883 			}
884 			break;
885 		case 0x03:
886 		case 0x53:
887 			/* The remote tells us what it thinks the sequence
888 			 * numbers are. I would have thought that there
889 			 * needs to be one and only one of these, but MCI
890 			 * want us to just ignore extras. (?) */
891 			if (resptype_seen == 0) {
892 				log(LOG_WARNING, "nglmi: no TYPE before SEQ\n");
893 				goto reject;
894 			}
895 			if (seq_seen != 0)	/* already seen seq numbers */
896 				goto nextIE;
897 			if (segsize != 2) {
898 				log(LOG_WARNING, "nglmi: bad SEQ sts size\n");
899 				goto reject;
900 			}
901 			if (sc->local_seq != data[3]) {
902 				log(LOG_WARNING, "nglmi: unexpected SEQ\n");
903 				goto reject;
904 			}
905 			seq_seen = 1;
906 			break;
907 		case 0x07:
908 		case 0x57:
909 			/* The remote tells us about a DLCI that it knows
910 			 * about. There may be many of these in a single
911 			 * status response */
912 			if (seq_seen != 1) {	/* already seen seq numbers? */
913 				log(LOG_WARNING,
914 				    "nglmi: No sequence before DLCI\n");
915 				goto reject;
916 			}
917 			if (resptype_seen != 2) {	/* must be full */
918 				log(LOG_WARNING,
919 				    "nglmi: No resp type before DLCI\n");
920 				goto reject;
921 			}
922 			if (GROUP4(sc)) {
923 				if (segsize != 6) {
924 					log(LOG_WARNING,
925 					    "nglmi: wrong IE segsize\n");
926 					goto reject;
927 				}
928 				dlci = ((u_short) data[2] & 0xff) << 8;
929 				dlci |= (data[3] & 0xff);
930 			} else {
931 				if (segsize != 3) {
932 					log(LOG_WARNING,
933 					    "nglmi: DLCI headersize of %d"
934 					    " not supported\n", segsize - 1);
935 					goto reject;
936 				}
937 				dlci = ((u_short) data[2] & 0x3f) << 4;
938 				dlci |= ((data[3] & 0x78) >> 3);
939 			}
940 			/* async can only have one of these */
941 #if 0				/* async not yet accepted */
942 			if (async && highest_dlci) {
943 				log(LOG_WARNING,
944 				    "nglmi: Async with > 1 DLCI\n");
945 				goto reject;
946 			}
947 #endif
948 			/* Annex D says these will always be Ascending, but
949 			 * the HP test for G4 says we should accept
950 			 * duplicates, so for now allow that. ( <= vs. < ) */
951 #if 0
952 			/* MCI tests want us to accept out of order for AnxD */
953 			if ((!GROUP4(sc)) && (dlci < highest_dlci)) {
954 				/* duplicate or mis-ordered dlci */
955 				/* (spec says they will increase in number) */
956 				log(LOG_WARNING, "nglmi: DLCI out of order\n");
957 				goto reject;
958 			}
959 #endif
960 			if (dlci > 1023) {
961 				log(LOG_WARNING, "nglmi: DLCI out of range\n");
962 				goto reject;
963 			}
964 			highest_dlci = dlci;
965 			break;
966 		default:
967 			log(LOG_WARNING,
968 			    "nglmi: unknown LMI segment type %d\n", segtype);
969 		}
970 nextIE:
971 		STEPBY(segsize + 2);
972 	}
973 	if (packetlen != 0) {	/* partial junk at end? */
974 		log(LOG_WARNING,
975 		    "nglmi: %d bytes extra at end of packet\n", packetlen);
976 		goto print;
977 	}
978 	if (resptype_seen == 0) {
979 		log(LOG_WARNING, "nglmi: No response type seen\n");
980 		goto reject;	/* had no response type */
981 	}
982 	if (seq_seen == 0) {
983 		log(LOG_WARNING, "nglmi: No sequence numbers seen\n");
984 		goto reject;	/* had no sequence numbers */
985 	}
986 	return (1);
987 
988 print:
989 	{
990 		int     i, j, k, pos;
991 		char    buf[100];
992 		int     loc;
993 		const	u_char *bp = mtod(m, const u_char *);
994 
995 		k = i = 0;
996 		loc = (m->m_len - packetlen);
997 		log(LOG_WARNING, "nglmi: error at location %d\n", loc);
998 		while (k < m->m_len) {
999 			pos = 0;
1000 			j = 0;
1001 			while ((j++ < 16) && k < m->m_len) {
1002 				pos += sprintf(buf + pos, "%c%02x",
1003 					       ((loc == k) ? '>' : ' '),
1004 					       bp[k]);
1005 				k++;
1006 			}
1007 			if (i == 0)
1008 				log(LOG_WARNING, "nglmi: packet data:%s\n", buf);
1009 			else
1010 				log(LOG_WARNING, "%04d              :%s\n", k, buf);
1011 			i++;
1012 		}
1013 	}
1014 	return (1);
1015 reject:
1016 	{
1017 		int     i, j, k, pos;
1018 		char    buf[100];
1019 		int     loc;
1020 		const	u_char *bp = mtod(m, const u_char *);
1021 
1022 		k = i = 0;
1023 		loc = (m->m_len - packetlen);
1024 		log(LOG_WARNING, "nglmi: error at location %d\n", loc);
1025 		while (k < m->m_len) {
1026 			pos = 0;
1027 			j = 0;
1028 			while ((j++ < 16) && k < m->m_len) {
1029 				pos += sprintf(buf + pos, "%c%02x",
1030 					       ((loc == k) ? '>' : ' '),
1031 					       bp[k]);
1032 				k++;
1033 			}
1034 			if (i == 0)
1035 				log(LOG_WARNING, "nglmi: packet data:%s\n", buf);
1036 			else
1037 				log(LOG_WARNING, "%04d              :%s\n", k, buf);
1038 			i++;
1039 		}
1040 	}
1041 	NG_FREE_M(m);
1042 	return (0);
1043 }
1044 
1045 /*
1046  * Do local shutdown processing..
1047  * Cut any remaining links and free our local resources.
1048  */
1049 static int
1050 nglmi_shutdown(node_p node)
1051 {
1052 	const sc_p sc = NG_NODE_PRIVATE(node);
1053 
1054 	NG_NODE_SET_PRIVATE(node, NULL);
1055 	NG_NODE_UNREF(sc->node);
1056 	free(sc, M_NETGRAPH);
1057 	return (0);
1058 }
1059 
1060 /*
1061  * Hook disconnection
1062  * For this type, removal of any link except "debug" destroys the node.
1063  */
1064 static int
1065 nglmi_disconnect(hook_p hook)
1066 {
1067 	const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
1068 
1069 	/* OK to remove debug hook(s) */
1070 	if (NG_HOOK_PRIVATE(hook) == NULL)
1071 		return (0);
1072 
1073 	/* Stop timer if it's currently active */
1074 	if (sc->flags & SCF_CONNECTED)
1075 		ng_uncallout(&sc->handle, sc->node);
1076 
1077 	/* Self-destruct */
1078 	if (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))
1079 		ng_rmnode_self(NG_HOOK_NODE(hook));
1080 	return (0);
1081 }
1082 
1083