xref: /dragonfly/sys/netgraph/lmi/ng_lmi.c (revision 86fe9e07)
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@freebsd.org>
38  *
39  * $FreeBSD: src/sys/netgraph/ng_lmi.c,v 1.5.2.3 2002/07/02 22:17:18 archie Exp $
40  * $DragonFly: src/sys/netgraph/lmi/ng_lmi.c,v 1.4 2004/06/02 14:43:00 eirikn Exp $
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 "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_rmnode;
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, meta_p meta);
100 
101 static struct ng_type typestruct = {
102 	NG_VERSION,
103 	NG_LMI_NODE_TYPE,
104 	NULL,
105 	nglmi_constructor,
106 	nglmi_rcvmsg,
107 	nglmi_rmnode,
108 	nglmi_newhook,
109 	NULL,
110 	NULL,
111 	nglmi_rcvdata,
112 	nglmi_rcvdata,
113 	nglmi_disconnect,
114 	NULL
115 };
116 NETGRAPH_INIT(lmi, &typestruct);
117 
118 /*
119  * Info and status per node
120  */
121 struct nglmi_softc {
122 	node_p  node;		/* netgraph node */
123 	int     flags;		/* state */
124 	int     poll_count;	/* the count of times for autolmi */
125 	int     poll_state;	/* state of auto detect machine */
126 	u_char  remote_seq;	/* sequence number the remote sent */
127 	u_char  local_seq;	/* last sequence number we sent */
128 	u_char  protoID;	/* 9 for group of 4, 8 otherwise */
129 	u_long  seq_retries;	/* sent this how many time so far */
130 	struct callout_handle handle;	/* see timeout(9) */
131 	int     liv_per_full;
132 	int     liv_rate;
133 	int     livs;
134 	int     need_full;
135 	hook_p  lmi_channel;	/* whatever we ended up using */
136 	hook_p  lmi_annexA;
137 	hook_p  lmi_annexD;
138 	hook_p  lmi_group4;
139 	hook_p  lmi_channel0;	/* auto-detect on DLCI 0 */
140 	hook_p  lmi_channel1023;/* auto-detect on DLCI 1023 */
141 	char   *protoname;	/* cache protocol name */
142 	u_char  dlci_state[MAXDLCI + 1];
143 	int     invalidx;	/* next dlci's to invalidate */
144 };
145 typedef struct nglmi_softc *sc_p;
146 
147 /*
148  * Other internal functions
149  */
150 static void	LMI_ticker(void *arg);
151 static void	nglmi_startup_fixed(sc_p sc, hook_p hook);
152 static void	nglmi_startup_auto(sc_p sc);
153 static void	nglmi_startup(sc_p sc);
154 static void	nglmi_inquire(sc_p sc, int full);
155 static void	ngauto_state_machine(sc_p sc);
156 
157 /*
158  * Values for 'flags' field
159  * NB: the SCF_CONNECTED flag is set if and only if the timer is running.
160  */
161 #define	SCF_CONNECTED	0x01	/* connected to something */
162 #define	SCF_AUTO	0x02	/* we are auto-detecting */
163 #define	SCF_FIXED	0x04	/* we are fixed from the start */
164 
165 #define	SCF_LMITYPE	0x18	/* mask for determining Annex mode */
166 #define	SCF_NOLMI	0x00	/* no LMI type selected yet */
167 #define	SCF_ANNEX_A	0x08	/* running annex A mode */
168 #define	SCF_ANNEX_D	0x10	/* running annex D mode */
169 #define	SCF_GROUP4	0x18	/* running group of 4 */
170 
171 #define SETLMITYPE(sc, annex)						\
172 do {									\
173 	(sc)->flags &= ~SCF_LMITYPE;					\
174 	(sc)->flags |= (annex);						\
175 } while (0)
176 
177 #define NOPROTO(sc) (((sc)->flags & SCF_LMITYPE) == SCF_NOLMI)
178 #define ANNEXA(sc) (((sc)->flags & SCF_LMITYPE) == SCF_ANNEX_A)
179 #define ANNEXD(sc) (((sc)->flags & SCF_LMITYPE) == SCF_ANNEX_D)
180 #define GROUP4(sc) (((sc)->flags & SCF_LMITYPE) == SCF_GROUP4)
181 
182 #define LMIPOLLSIZE	3
183 #define LMI_PATIENCE	8	/* declare all DLCI DOWN after N LMI failures */
184 
185 /*
186  * Node constructor
187  */
188 static int
189 nglmi_constructor(node_p *nodep)
190 {
191 	sc_p sc;
192 	int error = 0;
193 
194 	MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_NOWAIT);
195 	if (sc == NULL)
196 		return (ENOMEM);
197 	bzero(sc, sizeof(*sc));
198 
199 	callout_handle_init(&sc->handle);
200 	if ((error = ng_make_node_common(&typestruct, nodep))) {
201 		FREE(sc, M_NETGRAPH);
202 		return (error);
203 	}
204 	(*nodep)->private = sc;
205 	sc->protoname = NAME_NONE;
206 	sc->node = *nodep;
207 	sc->liv_per_full = NG_LMI_SEQ_PER_FULL;	/* make this dynamic */
208 	sc->liv_rate = NG_LMI_KEEPALIVE_RATE;
209 	return (0);
210 }
211 
212 /*
213  * The LMI channel has a private pointer which is the same as the
214  * node private pointer. The debug channel has a NULL private pointer.
215  */
216 static int
217 nglmi_newhook(node_p node, hook_p hook, const char *name)
218 {
219 	sc_p sc = node->private;
220 
221 	if (strcmp(name, NG_LMI_HOOK_DEBUG) == 0) {
222 		hook->private = NULL;
223 		return (0);
224 	}
225 	if (sc->flags & SCF_CONNECTED) {
226 		/* already connected, return an error */
227 		return (EINVAL);
228 	}
229 	if (strcmp(name, NG_LMI_HOOK_ANNEXA) == 0) {
230 		sc->lmi_annexA = hook;
231 		hook->private = node->private;
232 		sc->protoID = 8;
233 		SETLMITYPE(sc, SCF_ANNEX_A);
234 		sc->protoname = NAME_ANNEXA;
235 		nglmi_startup_fixed(sc, hook);
236 	} else if (strcmp(name, NG_LMI_HOOK_ANNEXD) == 0) {
237 		sc->lmi_annexD = hook;
238 		hook->private = node->private;
239 		sc->protoID = 8;
240 		SETLMITYPE(sc, SCF_ANNEX_D);
241 		sc->protoname = NAME_ANNEXD;
242 		nglmi_startup_fixed(sc, hook);
243 	} else if (strcmp(name, NG_LMI_HOOK_GROUPOF4) == 0) {
244 		sc->lmi_group4 = hook;
245 		hook->private = node->private;
246 		sc->protoID = 9;
247 		SETLMITYPE(sc, SCF_GROUP4);
248 		sc->protoname = NAME_GROUP4;
249 		nglmi_startup_fixed(sc, hook);
250 	} else if (strcmp(name, NG_LMI_HOOK_AUTO0) == 0) {
251 		/* Note this, and if B is already installed, we're complete */
252 		sc->lmi_channel0 = hook;
253 		sc->protoname = NAME_NONE;
254 		hook->private = node->private;
255 		if (sc->lmi_channel1023)
256 			nglmi_startup_auto(sc);
257 	} else if (strcmp(name, NG_LMI_HOOK_AUTO1023) == 0) {
258 		/* Note this, and if A is already installed, we're complete */
259 		sc->lmi_channel1023 = hook;
260 		sc->protoname = NAME_NONE;
261 		hook->private = node->private;
262 		if (sc->lmi_channel0)
263 			nglmi_startup_auto(sc);
264 	} else
265 		return (EINVAL);		/* unknown hook */
266 	return (0);
267 }
268 
269 /*
270  * We have just attached to a live (we hope) node.
271  * Fire out a LMI inquiry, and then start up the timers.
272  */
273 static void
274 LMI_ticker(void *arg)
275 {
276 	sc_p sc = arg;
277 	int s = splnet();
278 
279 	if (sc->flags & SCF_AUTO) {
280 		ngauto_state_machine(sc);
281 		sc->handle = timeout(LMI_ticker, sc, NG_LMI_POLL_RATE * hz);
282 	} else {
283 		if (sc->livs++ >= sc->liv_per_full) {
284 			nglmi_inquire(sc, 1);
285 			/* sc->livs = 0; *//* do this when we get the answer! */
286 		} else {
287 			nglmi_inquire(sc, 0);
288 		}
289 		sc->handle = timeout(LMI_ticker, sc, sc->liv_rate * hz);
290 	}
291 	splx(s);
292 }
293 
294 static void
295 nglmi_startup_fixed(sc_p sc, hook_p hook)
296 {
297 	sc->flags |= (SCF_FIXED | SCF_CONNECTED);
298 	sc->lmi_channel = hook;
299 	nglmi_startup(sc);
300 }
301 
302 static void
303 nglmi_startup_auto(sc_p sc)
304 {
305 	sc->flags |= (SCF_AUTO | SCF_CONNECTED);
306 	sc->poll_state = 0;	/* reset state machine */
307 	sc->poll_count = 0;
308 	nglmi_startup(sc);
309 }
310 
311 static void
312 nglmi_startup(sc_p sc)
313 {
314 	sc->remote_seq = 0;
315 	sc->local_seq = 1;
316 	sc->seq_retries = 0;
317 	sc->livs = sc->liv_per_full - 1;
318 	/* start off the ticker in 1 sec */
319 	sc->handle = timeout(LMI_ticker, sc, hz);
320 }
321 
322 #define META_PAD 16
323 static void
324 nglmi_inquire(sc_p sc, int full)
325 {
326 	struct mbuf *m;
327 	char   *cptr, *start;
328 	int     error;
329 	meta_p  meta = NULL;
330 
331 	if (sc->lmi_channel == NULL)
332 		return;
333 	MGETHDR(m, MB_DONTWAIT, MT_DATA);
334 	if (m == NULL) {
335 		log(LOG_ERR, "nglmi: unable to start up LMI processing\n");
336 		return;
337 	}
338 	m->m_pkthdr.rcvif = NULL;
339 	/* Allocate a meta struct (and leave some slop for options to be
340 	 * added by other modules). */
341 	/* MALLOC(meta, meta_p, sizeof( struct ng_meta) + META_PAD,
342 	 * M_NETGRAPH, M_NOWAIT); */
343 	MALLOC(meta, meta_p, sizeof(*meta) + META_PAD, M_NETGRAPH, M_NOWAIT);
344 	if (meta != NULL) {	/* if it failed, well, it was optional anyhow */
345 		meta->used_len = (u_short) sizeof(struct ng_meta);
346 		meta->allocated_len
347 		    = (u_short) sizeof(struct ng_meta) + META_PAD;
348 		meta->flags = 0;
349 		meta->priority = NG_LMI_LMI_PRIORITY;
350 		meta->discardability = -1;
351 	}
352 	m->m_data += 4;		/* leave some room for a header */
353 	cptr = start = mtod(m, char *);
354 	/* add in the header for an LMI inquiry. */
355 	*cptr++ = 0x03;		/* UI frame */
356 	if (GROUP4(sc))
357 		*cptr++ = 0x09;	/* proto discriminator */
358 	else
359 		*cptr++ = 0x08;	/* proto discriminator */
360 	*cptr++ = 0x00;		/* call reference */
361 	*cptr++ = 0x75;		/* inquiry */
362 
363 	/* If we are Annex-D, there is this extra thing.. */
364 	if (ANNEXD(sc))
365 		*cptr++ = 0x95;	/* ??? */
366 	/* Add a request type */
367 	if (ANNEXA(sc))
368 		*cptr++ = 0x51;	/* report type */
369 	else
370 		*cptr++ = 0x01;	/* report type */
371 	*cptr++ = 0x01;		/* size = 1 */
372 	if (full)
373 		*cptr++ = 0x00;	/* full */
374 	else
375 		*cptr++ = 0x01;	/* partial */
376 
377 	/* Add a link verification IE */
378 	if (ANNEXA(sc))
379 		*cptr++ = 0x53;	/* verification IE */
380 	else
381 		*cptr++ = 0x03;	/* verification IE */
382 	*cptr++ = 0x02;		/* 2 extra bytes */
383 	*cptr++ = sc->local_seq;
384 	*cptr++ = sc->remote_seq;
385 	sc->seq_retries++;
386 
387 	/* Send it */
388 	m->m_len = m->m_pkthdr.len = cptr - start;
389 	NG_SEND_DATA(error, sc->lmi_channel, m, meta);
390 
391 	/* If we've been sending requests for long enough, and there has
392 	 * been no response, then mark as DOWN, any DLCIs that are UP. */
393 	if (sc->seq_retries == LMI_PATIENCE) {
394 		int     count;
395 
396 		for (count = 0; count < MAXDLCI; count++)
397 			if (sc->dlci_state[count] == DLCI_UP)
398 				sc->dlci_state[count] = DLCI_DOWN;
399 	}
400 }
401 
402 /*
403  * State machine for LMI auto-detect. The transitions are ordered
404  * to try the more likely possibilities first.
405  */
406 static void
407 ngauto_state_machine(sc_p sc)
408 {
409 	if ((sc->poll_count <= 0) || (sc->poll_count > LMIPOLLSIZE)) {
410 		/* time to change states in the auto probe machine */
411 		/* capture wild values of poll_count while we are at it */
412 		sc->poll_count = LMIPOLLSIZE;
413 		sc->poll_state++;
414 	}
415 	switch (sc->poll_state) {
416 	case 7:
417 		log(LOG_WARNING, "nglmi: no response from exchange\n");
418 	default:		/* capture bad states */
419 		sc->poll_state = 1;
420 	case 1:
421 		sc->lmi_channel = sc->lmi_channel0;
422 		SETLMITYPE(sc, SCF_ANNEX_D);
423 		break;
424 	case 2:
425 		sc->lmi_channel = sc->lmi_channel1023;
426 		SETLMITYPE(sc, SCF_ANNEX_D);
427 		break;
428 	case 3:
429 		sc->lmi_channel = sc->lmi_channel0;
430 		SETLMITYPE(sc, SCF_ANNEX_A);
431 		break;
432 	case 4:
433 		sc->lmi_channel = sc->lmi_channel1023;
434 		SETLMITYPE(sc, SCF_GROUP4);
435 		break;
436 	case 5:
437 		sc->lmi_channel = sc->lmi_channel1023;
438 		SETLMITYPE(sc, SCF_ANNEX_A);
439 		break;
440 	case 6:
441 		sc->lmi_channel = sc->lmi_channel0;
442 		SETLMITYPE(sc, SCF_GROUP4);
443 		break;
444 	}
445 
446 	/* send an inquirey encoded appropriatly */
447 	nglmi_inquire(sc, 0);
448 	sc->poll_count--;
449 }
450 
451 /*
452  * Receive a netgraph control message.
453  */
454 static int
455 nglmi_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr,
456 	     struct ng_mesg **resp)
457 {
458 	int     error = 0;
459 	sc_p    sc = node->private;
460 
461 	switch (msg->header.typecookie) {
462 	case NGM_GENERIC_COOKIE:
463 		switch (msg->header.cmd) {
464 		case NGM_TEXT_STATUS:
465 		    {
466 			char   *arg;
467 			int     pos, count;
468 
469 			NG_MKRESPONSE(*resp, msg, NG_TEXTRESPONSE, M_NOWAIT);
470 			if (*resp == NULL) {
471 				error = ENOMEM;
472 				break;
473 			}
474 			arg = (*resp)->data;
475 			pos = sprintf(arg, "protocol %s ", sc->protoname);
476 			if (sc->flags & SCF_FIXED)
477 				pos += sprintf(arg + pos, "fixed\n");
478 			else if (sc->flags & SCF_AUTO)
479 				pos += sprintf(arg + pos, "auto-detecting\n");
480 			else
481 				pos += sprintf(arg + pos, "auto on dlci %d\n",
482 				    (sc->lmi_channel == sc->lmi_channel0) ?
483 				    0 : 1023);
484 			pos += sprintf(arg + pos,
485 			    "keepalive period: %d seconds\n", sc->liv_rate);
486 			pos += sprintf(arg + pos,
487 			    "unacknowledged keepalives: %ld\n",
488 			    sc->seq_retries);
489 			for (count = 0;
490 			     ((count <= MAXDLCI)
491 			      && (pos < (NG_TEXTRESPONSE - 20)));
492 			     count++) {
493 				if (sc->dlci_state[count]) {
494 					pos += sprintf(arg + pos,
495 					       "dlci %d %s\n", count,
496 					       (sc->dlci_state[count]
497 					== DLCI_UP) ? "up" : "down");
498 				}
499 			}
500 			(*resp)->header.arglen = pos + 1;
501 			break;
502 		    }
503 		default:
504 			error = EINVAL;
505 			break;
506 		}
507 		break;
508 	case NGM_LMI_COOKIE:
509 		switch (msg->header.cmd) {
510 		case NGM_LMI_GET_STATUS:
511 		    {
512 			struct nglmistat *stat;
513 			int k;
514 
515 			NG_MKRESPONSE(*resp, msg, sizeof(*stat), M_NOWAIT);
516 			if (!*resp) {
517 				error = ENOMEM;
518 				break;
519 			}
520 			stat = (struct nglmistat *) (*resp)->data;
521 			strncpy(stat->proto,
522 			     sc->protoname, sizeof(stat->proto) - 1);
523 			strncpy(stat->hook,
524 			      sc->protoname, sizeof(stat->hook) - 1);
525 			stat->autod = !!(sc->flags & SCF_AUTO);
526 			stat->fixed = !!(sc->flags & SCF_FIXED);
527 			for (k = 0; k <= MAXDLCI; k++) {
528 				switch (sc->dlci_state[k]) {
529 				case DLCI_UP:
530 					stat->up[k / 8] |= (1 << (k % 8));
531 					/* fall through */
532 				case DLCI_DOWN:
533 					stat->seen[k / 8] |= (1 << (k % 8));
534 					break;
535 				}
536 			}
537 			break;
538 		    }
539 		default:
540 			error = EINVAL;
541 			break;
542 		}
543 		break;
544 	default:
545 		error = EINVAL;
546 		break;
547 	}
548 	FREE(msg, M_NETGRAPH);
549 	return (error);
550 }
551 
552 #define STEPBY(stepsize)			\
553 	do {					\
554 		packetlen -= (stepsize);	\
555 		data += (stepsize);		\
556 	} while (0)
557 
558 /*
559  * receive data, and use it to update our status.
560  * Anything coming in on the debug port is discarded.
561  */
562 static int
563 nglmi_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
564 {
565 	sc_p    sc = hook->node->private;
566 	const	u_char *data;
567 	unsigned short dlci;
568 	u_short packetlen;
569 	int     resptype_seen = 0;
570 	int     seq_seen = 0;
571 
572 	if (hook->private == NULL) {
573 		goto drop;
574 	}
575 	packetlen = m->m_hdr.mh_len;
576 
577 	/* XXX what if it's more than 1 mbuf? */
578 	if ((packetlen > MHLEN) && !(m->m_flags & M_EXT)) {
579 		log(LOG_WARNING, "nglmi: packetlen (%d) too big\n", packetlen);
580 		goto drop;
581 	}
582 	if (m->m_len < packetlen && (m = m_pullup(m, packetlen)) == NULL) {
583 		log(LOG_WARNING,
584 		    "nglmi: m_pullup failed for %d bytes\n", packetlen);
585 		NG_FREE_META(meta);
586 		return (0);
587 	}
588 	if (nglmi_checkdata(hook, m, meta) == 0)
589 		return (0);
590 
591 	/* pass the first 4 bytes (already checked in the nglmi_checkdata()) */
592 	data = mtod(m, const u_char *);
593 	STEPBY(4);
594 
595 	/* Now check if there is a 'locking shift'. This is only seen in
596 	 * Annex D frames. don't bother checking, we already did that. Don't
597 	 * increment immediatly as it might not be there. */
598 	if (ANNEXD(sc))
599 		STEPBY(1);
600 
601 	/* If we get this far we should consider that it is a legitimate
602 	 * frame and we know what it is. */
603 	if (sc->flags & SCF_AUTO) {
604 		/* note the hook that this valid channel came from and drop
605 		 * out of auto probe mode. */
606 		if (ANNEXA(sc))
607 			sc->protoname = NAME_ANNEXA;
608 		else if (ANNEXD(sc))
609 			sc->protoname = NAME_ANNEXD;
610 		else if (GROUP4(sc))
611 			sc->protoname = NAME_GROUP4;
612 		else {
613 			log(LOG_ERR, "nglmi: No known type\n");
614 			goto drop;
615 		}
616 		sc->lmi_channel = hook;
617 		sc->flags &= ~SCF_AUTO;
618 		log(LOG_INFO, "nglmi: auto-detected %s LMI on DLCI %d\n",
619 		    sc->protoname, hook == sc->lmi_channel0 ? 0 : 1023);
620 	}
621 
622 	/* While there is more data in the status packet, keep processing
623 	 * status items. First make sure there is enough data for the
624 	 * segment descriptor's length field. */
625 	while (packetlen >= 2) {
626 		u_int   segtype = data[0];
627 		u_int   segsize = data[1];
628 
629 		/* Now that we know how long it claims to be, make sure
630 		 * there is enough data for the next seg. */
631 		if (packetlen < segsize + 2)
632 			break;
633 		switch (segtype) {
634 		case 0x01:
635 		case 0x51:
636 			if (resptype_seen) {
637 				log(LOG_WARNING, "nglmi: dup MSGTYPE\n");
638 				goto nextIE;
639 			}
640 			resptype_seen++;
641 			/* The remote end tells us what kind of response
642 			 * this is. Only expect a type 0 or 1. if we are a
643 			 * full status, invalidate a few DLCIs just to see
644 			 * that they are still ok. */
645 			if (segsize != 1)
646 				goto nextIE;
647 			switch (data[2]) {
648 			case 1:
649 				/* partial status, do no extra processing */
650 				break;
651 			case 0:
652 			    {
653 				int     count = 0;
654 				int     idx = sc->invalidx;
655 
656 				for (count = 0; count < 10; count++) {
657 					if (idx > MAXDLCI)
658 						idx = 0;
659 					if (sc->dlci_state[idx] == DLCI_UP)
660 						sc->dlci_state[idx] = DLCI_DOWN;
661 					idx++;
662 				}
663 				sc->invalidx = idx;
664 				/* we got and we wanted one. relax
665 				 * now.. but don't reset to 0 if it
666 				 * was unrequested. */
667 				if (sc->livs > sc->liv_per_full)
668 					sc->livs = 0;
669 				break;
670 			    }
671 			}
672 			break;
673 		case 0x03:
674 		case 0x53:
675 			/* The remote tells us what it thinks the sequence
676 			 * numbers are. If it's not size 2, it must be a
677 			 * duplicate to have gotten this far, skip it. */
678 			if (seq_seen != 0)	/* already seen seq numbers */
679 				goto nextIE;
680 			if (segsize != 2)
681 				goto nextIE;
682 			sc->remote_seq = data[2];
683 			if (sc->local_seq == data[3]) {
684 				sc->local_seq++;
685 				sc->seq_retries = 0;
686 				/* Note that all 3 Frame protocols seem to
687 				 * not like 0 as a sequence number. */
688 				if (sc->local_seq == 0)
689 					sc->local_seq = 1;
690 			}
691 			break;
692 		case 0x07:
693 		case 0x57:
694 			/* The remote tells us about a DLCI that it knows
695 			 * about. There may be many of these in a single
696 			 * status response */
697 			switch (segsize) {
698 			case 6:/* only on 'group of 4' */
699 				dlci = ((u_short) data[2] & 0xff) << 8;
700 				dlci |= (data[3] & 0xff);
701 				if ((dlci < 1024) && (dlci > 0)) {
702 				  /* XXX */
703 				}
704 				break;
705 			case 3:
706 				dlci = ((u_short) data[2] & 0x3f) << 4;
707 				dlci |= ((data[3] & 0x78) >> 3);
708 				if ((dlci < 1024) && (dlci > 0)) {
709 					/* set up the bottom half of the
710 					 * support for that dlci if it's not
711 					 * already been done */
712 					/* store this information somewhere */
713 				}
714 				break;
715 			default:
716 				goto nextIE;
717 			}
718 			if (sc->dlci_state[dlci] != DLCI_UP) {
719 				/* bring new DLCI to life */
720 				/* may do more here some day */
721 				if (sc->dlci_state[dlci] != DLCI_DOWN)
722 					log(LOG_INFO,
723 					    "nglmi: DLCI %d became active\n",
724 					    dlci);
725 				sc->dlci_state[dlci] = DLCI_UP;
726 			}
727 			break;
728 		}
729 nextIE:
730 		STEPBY(segsize + 2);
731 	}
732 	NG_FREE_DATA(m, meta);
733 	return (0);
734 
735 drop:
736 	NG_FREE_DATA(m, meta);
737 	return (EINVAL);
738 }
739 
740 /*
741  * Check that a packet is entirely kosha.
742  * return 1 of ok, and 0 if not.
743  * All data is discarded if a 0 is returned.
744  */
745 static int
746 nglmi_checkdata(hook_p hook, struct mbuf *m, meta_p meta)
747 {
748 	sc_p    sc = hook->node->private;
749 	const	u_char *data;
750 	u_short packetlen;
751 	unsigned short dlci;
752 	u_char  type;
753 	u_char  nextbyte;
754 	int     seq_seen = 0;
755 	int     resptype_seen = 0;	/* 0 , 1 (partial) or 2 (full) */
756 	int     highest_dlci = 0;
757 
758 	packetlen = m->m_hdr.mh_len;
759 	data = mtod(m, const u_char *);
760 	if (*data != 0x03) {
761 		log(LOG_WARNING, "nglmi: unexpected value in LMI(%d)\n", 1);
762 		goto reject;
763 	}
764 	STEPBY(1);
765 
766 	/* look at the protocol ID */
767 	nextbyte = *data;
768 	if (sc->flags & SCF_AUTO) {
769 		SETLMITYPE(sc, SCF_NOLMI);	/* start with a clean slate */
770 		switch (nextbyte) {
771 		case 0x8:
772 			sc->protoID = 8;
773 			break;
774 		case 0x9:
775 			SETLMITYPE(sc, SCF_GROUP4);
776 			sc->protoID = 9;
777 			break;
778 		default:
779 			log(LOG_WARNING, "nglmi: bad Protocol ID(%d)\n",
780 			    (int) nextbyte);
781 			goto reject;
782 		}
783 	} else {
784 		if (nextbyte != sc->protoID) {
785 			log(LOG_WARNING, "nglmi: unexpected Protocol ID(%d)\n",
786 			    (int) nextbyte);
787 			goto reject;
788 		}
789 	}
790 	STEPBY(1);
791 
792 	/* check call reference (always null in non ISDN frame relay) */
793 	if (*data != 0x00) {
794 		log(LOG_WARNING, "nglmi: unexpected Call Reference (0x%x)\n",
795 		    data[-1]);
796 		goto reject;
797 	}
798 	STEPBY(1);
799 
800 	/* check message type */
801 	switch ((type = *data)) {
802 	case 0x75:		/* Status enquiry */
803 		log(LOG_WARNING, "nglmi: unexpected message type(0x%x)\n",
804 		    data[-1]);
805 		goto reject;
806 	case 0x7D:		/* Status message */
807 		break;
808 	default:
809 		log(LOG_WARNING,
810 		    "nglmi: unexpected msg type(0x%x) \n", (int) type);
811 		goto reject;
812 	}
813 	STEPBY(1);
814 
815 	/* Now check if there is a 'locking shift'. This is only seen in
816 	 * Annex D frames. Don't increment immediately as it might not be
817 	 * there. */
818 	nextbyte = *data;
819 	if (sc->flags & SCF_AUTO) {
820 		if (!(GROUP4(sc))) {
821 			if (nextbyte == 0x95) {
822 				SETLMITYPE(sc, SCF_ANNEX_D);
823 				STEPBY(1);
824 			} else
825 				SETLMITYPE(sc, SCF_ANNEX_A);
826 		} else if (nextbyte == 0x95) {
827 			log(LOG_WARNING, "nglmi: locking shift seen in G4\n");
828 			goto reject;
829 		}
830 	} else {
831 		if (ANNEXD(sc)) {
832 			if (*data == 0x95)
833 				STEPBY(1);
834 			else {
835 				log(LOG_WARNING,
836 				    "nglmi: locking shift missing\n");
837 				goto reject;
838 			}
839 		} else if (*data == 0x95) {
840 			log(LOG_WARNING, "nglmi: locking shift seen\n");
841 			goto reject;
842 		}
843 	}
844 
845 	/* While there is more data in the status packet, keep processing
846 	 * status items. First make sure there is enough data for the
847 	 * segment descriptor's length field. */
848 	while (packetlen >= 2) {
849 		u_int   segtype = data[0];
850 		u_int   segsize = data[1];
851 
852 		/* Now that we know how long it claims to be, make sure
853 		 * there is enough data for the next seg. */
854 		if (packetlen < (segsize + 2)) {
855 			log(LOG_WARNING, "nglmi: IE longer than packet\n");
856 			break;
857 		}
858 		switch (segtype) {
859 		case 0x01:
860 		case 0x51:
861 			/* According to MCI's HP analyser, we should just
862 			 * ignore if there is mor ethan one of these (?). */
863 			if (resptype_seen) {
864 				log(LOG_WARNING, "nglmi: dup MSGTYPE\n");
865 				goto nextIE;
866 			}
867 			if (segsize != 1) {
868 				log(LOG_WARNING, "nglmi: MSGTYPE wrong size\n");
869 				goto reject;
870 			}
871 			/* The remote end tells us what kind of response
872 			 * this is. Only expect a type 0 or 1. if it was a
873 			 * full (type 0) check we just asked for a type
874 			 * full. */
875 			switch (data[2]) {
876 			case 1:/* partial */
877 				if (sc->livs > sc->liv_per_full) {
878 					log(LOG_WARNING,
879 					  "nglmi: LIV when FULL expected\n");
880 					goto reject;	/* need full */
881 				}
882 				resptype_seen = 1;
883 				break;
884 			case 0:/* full */
885 				/* Full response is always acceptable */
886 				resptype_seen = 2;
887 				break;
888 			default:
889 				log(LOG_WARNING,
890 				 "nglmi: Unknown report type %d\n", data[2]);
891 				goto reject;
892 			}
893 			break;
894 		case 0x03:
895 		case 0x53:
896 			/* The remote tells us what it thinks the sequence
897 			 * numbers are. I would have thought that there
898 			 * needs to be one and only one of these, but MCI
899 			 * want us to just ignore extras. (?) */
900 			if (resptype_seen == 0) {
901 				log(LOG_WARNING, "nglmi: no TYPE before SEQ\n");
902 				goto reject;
903 			}
904 			if (seq_seen != 0)	/* already seen seq numbers */
905 				goto nextIE;
906 			if (segsize != 2) {
907 				log(LOG_WARNING, "nglmi: bad SEQ sts size\n");
908 				goto reject;
909 			}
910 			if (sc->local_seq != data[3]) {
911 				log(LOG_WARNING, "nglmi: unexpected SEQ\n");
912 				goto reject;
913 			}
914 			seq_seen = 1;
915 			break;
916 		case 0x07:
917 		case 0x57:
918 			/* The remote tells us about a DLCI that it knows
919 			 * about. There may be many of these in a single
920 			 * status response */
921 			if (seq_seen != 1) {	/* already seen seq numbers? */
922 				log(LOG_WARNING,
923 				    "nglmi: No sequence before DLCI\n");
924 				goto reject;
925 			}
926 			if (resptype_seen != 2) {	/* must be full */
927 				log(LOG_WARNING,
928 				    "nglmi: No resp type before DLCI\n");
929 				goto reject;
930 			}
931 			if (GROUP4(sc)) {
932 				if (segsize != 6) {
933 					log(LOG_WARNING,
934 					    "nglmi: wrong IE segsize\n");
935 					goto reject;
936 				}
937 				dlci = ((u_short) data[2] & 0xff) << 8;
938 				dlci |= (data[3] & 0xff);
939 			} else {
940 				if (segsize != 3) {
941 					log(LOG_WARNING,
942 					    "nglmi: DLCI headersize of %d"
943 					    " not supported\n", segsize - 1);
944 					goto reject;
945 				}
946 				dlci = ((u_short) data[2] & 0x3f) << 4;
947 				dlci |= ((data[3] & 0x78) >> 3);
948 			}
949 			/* async can only have one of these */
950 #if 0				/* async not yet accepted */
951 			if (async && highest_dlci) {
952 				log(LOG_WARNING,
953 				    "nglmi: Async with > 1 DLCI\n");
954 				goto reject;
955 			}
956 #endif
957 			/* Annex D says these will always be Ascending, but
958 			 * the HP test for G4 says we should accept
959 			 * duplicates, so for now allow that. ( <= vs. < ) */
960 #if 0
961 			/* MCI tests want us to accept out of order for AnxD */
962 			if ((!GROUP4(sc)) && (dlci < highest_dlci)) {
963 				/* duplicate or mis-ordered dlci */
964 				/* (spec says they will increase in number) */
965 				log(LOG_WARNING, "nglmi: DLCI out of order\n");
966 				goto reject;
967 			}
968 #endif
969 			if (dlci > 1023) {
970 				log(LOG_WARNING, "nglmi: DLCI out of range\n");
971 				goto reject;
972 			}
973 			highest_dlci = dlci;
974 			break;
975 		default:
976 			log(LOG_WARNING,
977 			    "nglmi: unknown LMI segment type %d\n", segtype);
978 		}
979 nextIE:
980 		STEPBY(segsize + 2);
981 	}
982 	if (packetlen != 0) {	/* partial junk at end? */
983 		log(LOG_WARNING,
984 		    "nglmi: %d bytes extra at end of packet\n", packetlen);
985 		goto print;
986 	}
987 	if (resptype_seen == 0) {
988 		log(LOG_WARNING, "nglmi: No response type seen\n");
989 		goto reject;	/* had no response type */
990 	}
991 	if (seq_seen == 0) {
992 		log(LOG_WARNING, "nglmi: No sequence numbers seen\n");
993 		goto reject;	/* had no sequence numbers */
994 	}
995 	return (1);
996 
997 print:
998 	{
999 		int     i, j, k, pos;
1000 		char    buf[100];
1001 		int     loc;
1002 		const	u_char *bp = mtod(m, const u_char *);
1003 
1004 		k = i = 0;
1005 		loc = (m->m_hdr.mh_len - packetlen);
1006 		log(LOG_WARNING, "nglmi: error at location %d\n", loc);
1007 		while (k < m->m_hdr.mh_len) {
1008 			pos = 0;
1009 			j = 0;
1010 			while ((j++ < 16) && k < m->m_hdr.mh_len) {
1011 				pos += sprintf(buf + pos, "%c%02x",
1012 					       ((loc == k) ? '>' : ' '),
1013 					       bp[k]);
1014 				k++;
1015 			}
1016 			if (i == 0)
1017 				log(LOG_WARNING, "nglmi: packet data:%s\n", buf);
1018 			else
1019 				log(LOG_WARNING, "%04d              :%s\n", k, buf);
1020 			i++;
1021 		}
1022 	}
1023 	return (1);
1024 reject:
1025 	{
1026 		int     i, j, k, pos;
1027 		char    buf[100];
1028 		int     loc;
1029 		const	u_char *bp = mtod(m, const u_char *);
1030 
1031 		k = i = 0;
1032 		loc = (m->m_hdr.mh_len - packetlen);
1033 		log(LOG_WARNING, "nglmi: error at location %d\n", loc);
1034 		while (k < m->m_hdr.mh_len) {
1035 			pos = 0;
1036 			j = 0;
1037 			while ((j++ < 16) && k < m->m_hdr.mh_len) {
1038 				pos += sprintf(buf + pos, "%c%02x",
1039 					       ((loc == k) ? '>' : ' '),
1040 					       bp[k]);
1041 				k++;
1042 			}
1043 			if (i == 0)
1044 				log(LOG_WARNING, "nglmi: packet data:%s\n", buf);
1045 			else
1046 				log(LOG_WARNING, "%04d              :%s\n", k, buf);
1047 			i++;
1048 		}
1049 	}
1050 	NG_FREE_DATA(m, meta);
1051 	return (0);
1052 }
1053 
1054 /*
1055  * Do local shutdown processing..
1056  * Cut any remaining links and free our local resources.
1057  */
1058 static int
1059 nglmi_rmnode(node_p node)
1060 {
1061 	const sc_p sc = node->private;
1062 
1063 	node->flags |= NG_INVALID;
1064 	ng_cutlinks(node);
1065 	ng_unname(node);
1066 	node->private = NULL;
1067 	ng_unref(sc->node);
1068 	FREE(sc, M_NETGRAPH);
1069 	return (0);
1070 }
1071 
1072 /*
1073  * Hook disconnection
1074  * For this type, removal of any link except "debug" destroys the node.
1075  */
1076 static int
1077 nglmi_disconnect(hook_p hook)
1078 {
1079 	const sc_p sc = hook->node->private;
1080 
1081 	/* OK to remove debug hook(s) */
1082 	if (hook->private == NULL)
1083 		return (0);
1084 
1085 	/* Stop timer if it's currently active */
1086 	if (sc->flags & SCF_CONNECTED)
1087 		untimeout(LMI_ticker, sc, sc->handle);
1088 
1089 	/* Self-destruct */
1090 	ng_rmnode(hook->node);
1091 	return (0);
1092 }
1093 
1094