1 /*
2  * ng_h4.c
3  */
4 
5 /*-
6  * Copyright (c) 2001-2002 Maksim Yevmenkin <m_evmenkin@yahoo.com>
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  *
30  * $Id: ng_h4.c,v 1.10 2005/10/31 17:57:43 max Exp $
31  * $FreeBSD: src/sys/netgraph/bluetooth/drivers/h4/ng_h4.c,v 1.17 2007/08/13 17:19:28 emax Exp $
32  * $DragonFly: src/sys/netgraph7/bluetooth/drivers/h4/ng_h4.c,v 1.2 2008/06/26 23:05:40 dillon Exp $
33  * $DragonFly: src/sys/netgraph7/bluetooth/drivers/h4/ng_h4.c,v 1.2 2008/06/26 23:05:40 dillon Exp $
34  *
35  * Based on:
36  * ---------
37  *
38  * FreeBSD: src/sys/netgraph/ng_tty.c
39  * Author: Archie Cobbs <archie@freebsd.org>
40  *
41  */
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/kernel.h>
46 #include <sys/conf.h>
47 #include <sys/endian.h>
48 #include <sys/errno.h>
49 #include <sys/fcntl.h>
50 #include <sys/malloc.h>
51 #include <sys/mbuf.h>
52 #include <sys/priv.h>
53 #include <sys/socket.h>
54 #include <sys/tty.h>
55 #include <sys/ttycom.h>
56 #include <net/if.h>
57 #include <net/if_var.h>
58 #include "ng_message.h"
59 #include "netgraph.h"
60 #include "ng_parse.h"
61 #include "bluetooth/include/ng_bluetooth.h"
62 #include "bluetooth/include/ng_hci.h"
63 #include "bluetooth/include/ng_h4.h"
64 #include "bluetooth/drivers/h4/ng_h4_var.h"
65 #include "bluetooth/drivers/h4/ng_h4_prse.h"
66 
67 /*****************************************************************************
68  *****************************************************************************
69  ** This node implements a Bluetooth HCI UART transport layer as per chapter
70  ** H4 of the Bluetooth Specification Book v1.1. It is a terminal line
71  ** discipline that is also a netgraph node. Installing this line discipline
72  ** on a terminal device instantiates a new netgraph node of this type, which
73  ** allows access to the device via the "hook" hook of the node.
74  **
75  ** Once the line discipline is installed, you can find out the name of the
76  ** corresponding netgraph node via a NGIOCGINFO ioctl().
77  *****************************************************************************
78  *****************************************************************************/
79 
80 /* MALLOC define */
81 #ifndef NG_SEPARATE_MALLOC
82 MALLOC_DEFINE(M_NETGRAPH_H4, "netgraph_h4", "Netgraph Bluetooth H4 node");
83 #else
84 #define M_NETGRAPH_H4 M_NETGRAPH
85 #endif /* NG_SEPARATE_MALLOC */
86 
87 /* Line discipline methods */
88 static int	ng_h4_open	(struct cdev *, struct tty *);
89 static int	ng_h4_close	(struct tty *, int);
90 static int	ng_h4_read	(struct tty *, struct uio *, int);
91 static int	ng_h4_write	(struct tty *, struct uio *, int);
92 static int	ng_h4_input	(int, struct tty *);
93 static int	ng_h4_start	(struct tty *);
94 static int	ng_h4_ioctl	(struct tty *, u_long, caddr_t,
95 					int, struct thread *);
96 
97 /* Line discipline descriptor */
98 static struct linesw		ng_h4_disc = {
99 	ng_h4_open,		/* open */
100 	ng_h4_close,		/* close */
101 	ng_h4_read,		/* read */
102 	ng_h4_write,		/* write */
103 	ng_h4_ioctl,		/* ioctl */
104 	ng_h4_input,		/* input */
105 	ng_h4_start,		/* start */
106 	ttymodem		/* modem */
107 };
108 
109 /* Netgraph methods */
110 static ng_constructor_t		ng_h4_constructor;
111 static ng_rcvmsg_t		ng_h4_rcvmsg;
112 static ng_shutdown_t		ng_h4_shutdown;
113 static ng_newhook_t		ng_h4_newhook;
114 static ng_connect_t		ng_h4_connect;
115 static ng_rcvdata_t		ng_h4_rcvdata;
116 static ng_disconnect_t		ng_h4_disconnect;
117 
118 /* Other stuff */
119 static void	ng_h4_process_timeout	(node_p, hook_p, void *, int);
120 static int	ng_h4_mod_event		(module_t, int, void *);
121 
122 /* Netgraph node type descriptor */
123 static struct ng_type		typestruct = {
124 	.version =	NG_ABI_VERSION,
125 	.name =		NG_H4_NODE_TYPE,
126 	.mod_event =	ng_h4_mod_event,
127 	.constructor =	ng_h4_constructor,
128 	.rcvmsg =	ng_h4_rcvmsg,
129 	.shutdown =	ng_h4_shutdown,
130 	.newhook =	ng_h4_newhook,
131 	.connect =	ng_h4_connect,
132 	.rcvdata =	ng_h4_rcvdata,
133 	.disconnect =	ng_h4_disconnect,
134 	.cmdlist =	ng_h4_cmdlist
135 };
136 NETGRAPH_INIT(h4, &typestruct);
137 MODULE_VERSION(ng_h4, NG_BLUETOOTH_VERSION);
138 
139 static int	ng_h4_node = 0;
140 
141 /*****************************************************************************
142  *****************************************************************************
143  **			    Line discipline methods
144  *****************************************************************************
145  *****************************************************************************/
146 
147 /*
148  * Set our line discipline on the tty.
149  */
150 
151 static int
152 ng_h4_open(struct cdev *dev, struct tty *tp)
153 {
154 	struct thread	*td = curthread;
155 	char		 name[NG_NODESIZ];
156 	ng_h4_info_p	 sc = NULL;
157 	int		 error;
158 
159 	/* Super-user only */
160 	error = priv_check(td, PRIV_NETGRAPH_TTY); /* XXX */
161 	if (error != 0)
162 		return (error);
163 
164 	/* Initialize private struct */
165 	MALLOC(sc, ng_h4_info_p, sizeof(*sc), M_NETGRAPH_H4, M_WAITOK | M_NULLOK | M_ZERO);
166 	if (sc == NULL)
167 		return (ENOMEM);
168 
169 	sc->tp = tp;
170 	sc->debug = NG_H4_WARN_LEVEL;
171 
172 	sc->state = NG_H4_W4_PKT_IND;
173 	sc->want = 1;
174 	sc->got = 0;
175 
176 	mtx_init(&sc->outq.ifq_mtx, "ng_h4 node+queue", NULL, MTX_DEF);
177 	IFQ_SET_MAXLEN(&sc->outq, NG_H4_DEFAULTQLEN);
178 	ng_callout_init(&sc->timo);
179 
180 	NG_H4_LOCK(sc);
181 
182 	/* Setup netgraph node */
183 	error = ng_make_node_common(&typestruct, &sc->node);
184 	if (error != 0) {
185 		NG_H4_UNLOCK(sc);
186 
187 		printf("%s: Unable to create new node!\n", __func__);
188 
189 		mtx_destroy(&sc->outq.ifq_mtx);
190 		bzero(sc, sizeof(*sc));
191 		FREE(sc, M_NETGRAPH_H4);
192 
193 		return (error);
194 	}
195 
196 	/* Assign node its name */
197 	snprintf(name, sizeof(name), "%s%d", typestruct.name, ng_h4_node ++);
198 
199 	error = ng_name_node(sc->node, name);
200 	if (error != 0) {
201 		NG_H4_UNLOCK(sc);
202 
203 		printf("%s: %s - node name exists?\n", __func__, name);
204 
205 		NG_NODE_UNREF(sc->node);
206 		mtx_destroy(&sc->outq.ifq_mtx);
207 		bzero(sc, sizeof(*sc));
208 		FREE(sc, M_NETGRAPH_H4);
209 
210 		return (error);
211 	}
212 
213 	/* Set back pointers */
214 	NG_NODE_SET_PRIVATE(sc->node, sc);
215 	tp->t_lsc = (caddr_t) sc;
216 
217 	/* The node has to be a WRITER because data can change node status */
218 	NG_NODE_FORCE_WRITER(sc->node);
219 
220 	/*
221 	 * Pre-allocate cblocks to the an appropriate amount.
222 	 * I'm not sure what is appropriate.
223 	 */
224 
225 	ttyflush(tp, FREAD | FWRITE);
226 	clist_alloc_cblocks(&tp->t_canq, 0, 0);
227 	clist_alloc_cblocks(&tp->t_rawq, 0, 0);
228 	clist_alloc_cblocks(&tp->t_outq,
229 		MLEN + NG_H4_HIWATER, MLEN + NG_H4_HIWATER);
230 
231 	NG_H4_UNLOCK(sc);
232 
233 	return (error);
234 } /* ng_h4_open */
235 
236 /*
237  * Line specific close routine, called from device close routine
238  * and from ttioctl. This causes the node to be destroyed as well.
239  */
240 
241 static int
242 ng_h4_close(struct tty *tp, int flag)
243 {
244 	ng_h4_info_p	sc = (ng_h4_info_p) tp->t_lsc;
245 
246 	ttyflush(tp, FREAD | FWRITE);
247 	clist_free_cblocks(&tp->t_outq);
248 
249 	if (sc != NULL) {
250 		NG_H4_LOCK(sc);
251 
252 		if (callout_pending(&sc->timo))
253 			ng_uncallout(&sc->timo, sc->node);
254 
255 		tp->t_lsc = NULL;
256 		sc->dying = 1;
257 
258 		NG_H4_UNLOCK(sc);
259 
260 		ng_rmnode_self(sc->node);
261 	}
262 
263 	return (0);
264 } /* ng_h4_close */
265 
266 /*
267  * Once the device has been turned into a node, we don't allow reading.
268  */
269 
270 static int
271 ng_h4_read(struct tty *tp, struct uio *uio, int flag)
272 {
273 	return (EIO);
274 } /* ng_h4_read */
275 
276 /*
277  * Once the device has been turned into a node, we don't allow writing.
278  */
279 
280 static int
281 ng_h4_write(struct tty *tp, struct uio *uio, int flag)
282 {
283 	return (EIO);
284 } /* ng_h4_write */
285 
286 /*
287  * We implement the NGIOCGINFO ioctl() defined in ng_message.h.
288  */
289 
290 static int
291 ng_h4_ioctl(struct tty *tp, u_long cmd, caddr_t data, int flag,
292 		struct thread *td)
293 {
294 	ng_h4_info_p	sc = (ng_h4_info_p) tp->t_lsc;
295 	int		error = 0;
296 
297 	if (sc == NULL)
298 		return (ENXIO);
299 
300 	NG_H4_LOCK(sc);
301 
302 	switch (cmd) {
303 	case NGIOCGINFO:
304 #undef	NI
305 #define NI(x)	((struct nodeinfo *)(x))
306 
307 		bzero(data, sizeof(*NI(data)));
308 
309 		if (NG_NODE_HAS_NAME(sc->node))
310 			strncpy(NI(data)->name, NG_NODE_NAME(sc->node),
311 				sizeof(NI(data)->name) - 1);
312 
313 		strncpy(NI(data)->type, sc->node->nd_type->name,
314 			sizeof(NI(data)->type) - 1);
315 
316 		NI(data)->id = (u_int32_t) ng_node2ID(sc->node);
317 		NI(data)->hooks = NG_NODE_NUMHOOKS(sc->node);
318 		break;
319 
320 	default:
321 		error = ENOIOCTL;
322 		break;
323 	}
324 
325 	NG_H4_UNLOCK(sc);
326 
327 	return (error);
328 } /* ng_h4_ioctl */
329 
330 /*
331  * Receive data coming from the device. We get one character at a time, which
332  * is kindof silly.
333  */
334 
335 static int
336 ng_h4_input(int c, struct tty *tp)
337 {
338 	ng_h4_info_p	sc = (ng_h4_info_p) tp->t_lsc;
339 
340 	if (sc == NULL || tp != sc->tp ||
341 	    sc->node == NULL || NG_NODE_NOT_VALID(sc->node))
342 		return (0);
343 
344 	NG_H4_LOCK(sc);
345 
346 	/* Check for error conditions */
347 	if ((tp->t_state & TS_CONNECTED) == 0) {
348 		NG_H4_INFO("%s: %s - no carrier\n", __func__,
349 			NG_NODE_NAME(sc->node));
350 
351 		sc->state = NG_H4_W4_PKT_IND;
352 		sc->want = 1;
353 		sc->got = 0;
354 
355 		NG_H4_UNLOCK(sc);
356 
357 		return (0); /* XXX Loss of synchronization here! */
358 	}
359 
360 	/* Check for framing error or overrun on this char */
361 	if (c & TTY_ERRORMASK) {
362 		NG_H4_ERR("%s: %s - line error %#x, c=%#x\n", __func__,
363 			NG_NODE_NAME(sc->node), c & TTY_ERRORMASK,
364 			c & TTY_CHARMASK);
365 
366 		NG_H4_STAT_IERROR(sc->stat);
367 
368 		sc->state = NG_H4_W4_PKT_IND;
369 		sc->want = 1;
370 		sc->got = 0;
371 
372 		NG_H4_UNLOCK(sc);
373 
374 		return (0); /* XXX Loss of synchronization here! */
375 	}
376 
377 	NG_H4_STAT_BYTES_RECV(sc->stat, 1);
378 
379 	/* Append char to mbuf */
380 	if (sc->got >= sizeof(sc->ibuf)) {
381 		NG_H4_ALERT("%s: %s - input buffer overflow, c=%#x, got=%d\n",
382 			__func__, NG_NODE_NAME(sc->node), c & TTY_CHARMASK,
383 			sc->got);
384 
385 		NG_H4_STAT_IERROR(sc->stat);
386 
387 		sc->state = NG_H4_W4_PKT_IND;
388 		sc->want = 1;
389 		sc->got = 0;
390 
391 		NG_H4_UNLOCK(sc);
392 
393 		return (0); /* XXX Loss of synchronization here! */
394 	}
395 
396 	sc->ibuf[sc->got ++] = (c & TTY_CHARMASK);
397 
398 	NG_H4_INFO("%s: %s - got char %#x, want=%d, got=%d\n", __func__,
399 		NG_NODE_NAME(sc->node), c, sc->want, sc->got);
400 
401 	if (sc->got < sc->want) {
402 		NG_H4_UNLOCK(sc);
403 
404 		return (0); /* Wait for more */
405 	}
406 
407 	switch (sc->state) {
408 	/* Got packet indicator */
409 	case NG_H4_W4_PKT_IND:
410 		NG_H4_INFO("%s: %s - got packet indicator %#x\n", __func__,
411 			NG_NODE_NAME(sc->node), sc->ibuf[0]);
412 
413 		sc->state = NG_H4_W4_PKT_HDR;
414 
415 		/*
416 		 * Since packet indicator included in the packet header
417 		 * just set sc->want to sizeof(packet header).
418 		 */
419 
420 		switch (sc->ibuf[0]) {
421 		case NG_HCI_ACL_DATA_PKT:
422 			sc->want = sizeof(ng_hci_acldata_pkt_t);
423 			break;
424 
425 		case NG_HCI_SCO_DATA_PKT:
426 			sc->want = sizeof(ng_hci_scodata_pkt_t);
427 			break;
428 
429 		case NG_HCI_EVENT_PKT:
430 			sc->want = sizeof(ng_hci_event_pkt_t);
431 			break;
432 
433 		default:
434 			NG_H4_WARN("%s: %s - ignoring unknown packet " \
435 				"type=%#x\n", __func__, NG_NODE_NAME(sc->node),
436 				sc->ibuf[0]);
437 
438 			NG_H4_STAT_IERROR(sc->stat);
439 
440 			sc->state = NG_H4_W4_PKT_IND;
441 			sc->want = 1;
442 			sc->got = 0;
443 			break;
444 		}
445 		break;
446 
447 	/* Got packet header */
448 	case NG_H4_W4_PKT_HDR:
449 		sc->state = NG_H4_W4_PKT_DATA;
450 
451 		switch (sc->ibuf[0]) {
452 		case NG_HCI_ACL_DATA_PKT:
453 			c = le16toh(((ng_hci_acldata_pkt_t *)
454 				(sc->ibuf))->length);
455 			break;
456 
457 		case NG_HCI_SCO_DATA_PKT:
458 			c = ((ng_hci_scodata_pkt_t *)(sc->ibuf))->length;
459 			break;
460 
461 		case NG_HCI_EVENT_PKT:
462 			c = ((ng_hci_event_pkt_t *)(sc->ibuf))->length;
463 			break;
464 
465 		default:
466 			KASSERT((0), ("Invalid packet type=%#x\n",
467 				sc->ibuf[0]));
468 			break;
469 		}
470 
471 		NG_H4_INFO("%s: %s - got packet header, packet type=%#x, " \
472 			"packet size=%d, payload size=%d\n", __func__,
473 			NG_NODE_NAME(sc->node), sc->ibuf[0], sc->got, c);
474 
475 		if (c > 0) {
476 			sc->want += c;
477 
478 			/*
479 			 * Try to prevent possible buffer overrun
480 			 *
481 			 * XXX I'm *really* confused here. It turns out
482 			 * that Xircom card sends us packets with length
483 			 * greater then 512 bytes! This is greater then
484 			 * our old receive buffer (ibuf) size. In the same
485 			 * time the card demands from us *not* to send
486 			 * packets greater then 192 bytes. Weird! How the
487 			 * hell i should know how big *receive* buffer
488 			 * should be? For now increase receiving buffer
489 			 * size to 1K and add the following check.
490 			 */
491 
492 			if (sc->want >= sizeof(sc->ibuf)) {
493 				int	b;
494 
495 				NG_H4_ALERT("%s: %s - packet too big for " \
496 					"buffer, type=%#x, got=%d, want=%d, " \
497 					"length=%d\n", __func__,
498 					NG_NODE_NAME(sc->node), sc->ibuf[0],
499 					sc->got, sc->want, c);
500 
501 				NG_H4_ALERT("Packet header:\n");
502 				for (b = 0; b < sc->got; b++)
503 					NG_H4_ALERT("%#x ", sc->ibuf[b]);
504 				NG_H4_ALERT("\n");
505 
506 				/* Reset state */
507 				NG_H4_STAT_IERROR(sc->stat);
508 
509 				sc->state = NG_H4_W4_PKT_IND;
510 				sc->want = 1;
511 				sc->got = 0;
512 			}
513 
514 			break;
515 		}
516 
517 		/* else FALLTHROUGH and deliver frame */
518 		/* XXX Is this true? Should we deliver empty frame? */
519 
520 	/* Got packet data */
521 	case NG_H4_W4_PKT_DATA:
522 		NG_H4_INFO("%s: %s - got full packet, packet type=%#x, " \
523 			"packet size=%d\n", __func__,
524 			NG_NODE_NAME(sc->node), sc->ibuf[0], sc->got);
525 
526 		if (sc->hook != NULL && NG_HOOK_IS_VALID(sc->hook)) {
527 			struct mbuf	*m = NULL;
528 
529 			MGETHDR(m, MB_DONTWAIT, MT_DATA);
530 			if (m != NULL) {
531 				m->m_pkthdr.len = 0;
532 
533 				/* XXX m_copyback() is stupid */
534 				m->m_len = min(MHLEN, sc->got);
535 
536 				m_copyback(m, 0, sc->got, sc->ibuf);
537 				NG_SEND_DATA_ONLY(c, sc->hook, m);
538 			} else {
539 				NG_H4_ERR("%s: %s - could not get mbuf\n",
540 					__func__, NG_NODE_NAME(sc->node));
541 
542 				NG_H4_STAT_IERROR(sc->stat);
543 			}
544 		}
545 
546 		sc->state = NG_H4_W4_PKT_IND;
547 		sc->want = 1;
548 		sc->got = 0;
549 
550 		NG_H4_STAT_PCKTS_RECV(sc->stat);
551 		break;
552 
553 	default:
554 		KASSERT((0), ("Invalid H4 node state=%d", sc->state));
555 		break;
556 	}
557 
558 	NG_H4_UNLOCK(sc);
559 
560 	return (0);
561 } /* ng_h4_input */
562 
563 /*
564  * This is called when the device driver is ready for more output. Called from
565  * tty system.
566  */
567 
568 static int
569 ng_h4_start(struct tty *tp)
570 {
571 	ng_h4_info_p	 sc = (ng_h4_info_p) tp->t_lsc;
572 	struct mbuf	*m = NULL;
573 	int		 size;
574 
575 	if (sc == NULL || tp != sc->tp ||
576 	    sc->node == NULL || NG_NODE_NOT_VALID(sc->node))
577 		return (0);
578 
579 #if 0
580 	while (tp->t_outq.c_cc < NG_H4_HIWATER) { /* XXX 2.2 specific ? */
581 #else
582 	while (1) {
583 #endif
584 		/* Remove first mbuf from queue */
585 		IF_DEQUEUE(&sc->outq, m);
586 		if (m == NULL)
587 			break;
588 
589 		/* Send as much of it as possible */
590 		while (m != NULL) {
591 			size = m->m_len - b_to_q(mtod(m, u_char *),
592 					m->m_len, &tp->t_outq);
593 
594 			NG_H4_LOCK(sc);
595 			NG_H4_STAT_BYTES_SENT(sc->stat, size);
596 			NG_H4_UNLOCK(sc);
597 
598 			m->m_data += size;
599 			m->m_len -= size;
600 			if (m->m_len > 0)
601 				break;	/* device can't take no more */
602 
603 			m = m_free(m);
604 		}
605 
606 		/* Put remainder of mbuf chain (if any) back on queue */
607 		if (m != NULL) {
608 			IF_PREPEND(&sc->outq, m);
609 			break;
610 		}
611 
612 		/* Full packet has been sent */
613 		NG_H4_LOCK(sc);
614 		NG_H4_STAT_PCKTS_SENT(sc->stat);
615 		NG_H4_UNLOCK(sc);
616 	}
617 
618 	/*
619 	 * Call output process whether or not there is any output. We are
620 	 * being called in lieu of ttstart and must do what it would.
621 	 */
622 
623 	tt_oproc(sc->tp);
624 
625 	/*
626 	 * This timeout is needed for operation on a pseudo-tty, because the
627 	 * pty code doesn't call pppstart after it has drained the t_outq.
628 	 */
629 
630 	NG_H4_LOCK(sc);
631 
632 	if (!IFQ_IS_EMPTY(&sc->outq) && !callout_pending(&sc->timo))
633 		ng_callout(&sc->timo, sc->node, NULL, 1,
634 			ng_h4_process_timeout, NULL, 0);
635 
636 	NG_H4_UNLOCK(sc);
637 
638 	return (0);
639 } /* ng_h4_start */
640 
641 /*****************************************************************************
642  *****************************************************************************
643  **			    Netgraph node methods
644  *****************************************************************************
645  *****************************************************************************/
646 
647 /*
648  * Initialize a new node of this type. We only allow nodes to be created as
649  * a result of setting the line discipline on a tty, so always return an error
650  * if not.
651  */
652 
653 static int
654 ng_h4_constructor(node_p node)
655 {
656 	return (EOPNOTSUPP);
657 } /* ng_h4_constructor */
658 
659 /*
660  * Add a new hook. There can only be one.
661  */
662 
663 static int
664 ng_h4_newhook(node_p node, hook_p hook, const char *name)
665 {
666 	ng_h4_info_p	sc = (ng_h4_info_p) NG_NODE_PRIVATE(node);
667 
668 	if (strcmp(name, NG_H4_HOOK) != 0)
669 		return (EINVAL);
670 
671 	NG_H4_LOCK(sc);
672 
673 	if (sc->hook != NULL) {
674 		NG_H4_UNLOCK(sc);
675 		return (EISCONN);
676 	}
677 	sc->hook = hook;
678 
679 	NG_H4_UNLOCK(sc);
680 
681 	return (0);
682 } /* ng_h4_newhook */
683 
684 /*
685  * Connect hook. Just say yes.
686  */
687 
688 static int
689 ng_h4_connect(hook_p hook)
690 {
691 	ng_h4_info_p	sc = (ng_h4_info_p) NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
692 
693 	if (hook != sc->hook)
694 		panic("%s: hook != sc->hook\n", __func__);
695 
696 	NG_HOOK_FORCE_QUEUE(NG_HOOK_PEER(hook));
697 	NG_HOOK_FORCE_QUEUE(hook);
698 
699 	return (0);
700 } /* ng_h4_connect */
701 
702 /*
703  * Disconnect the hook
704  */
705 
706 static int
707 ng_h4_disconnect(hook_p hook)
708 {
709 	ng_h4_info_p	sc = (ng_h4_info_p) NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
710 
711 	/*
712 	 * We need to check for sc != NULL because we can be called from
713 	 * ng_h4_close() via ng_rmnode_self()
714 	 */
715 
716 	if (sc != NULL) {
717 		if (hook != sc->hook)
718 			panic("%s: hook != sc->hook\n", __func__);
719 
720 		NG_H4_LOCK(sc);
721 
722 		/* XXX do we have to untimeout and drain out queue? */
723 		if (callout_pending(&sc->timo))
724 			ng_uncallout(&sc->timo, sc->node);
725 
726 		_IF_DRAIN(&sc->outq);
727 
728 		sc->state = NG_H4_W4_PKT_IND;
729 		sc->want = 1;
730 		sc->got = 0;
731 
732 		sc->hook = NULL;
733 
734 		NG_H4_UNLOCK(sc);
735 	}
736 
737 	return (0);
738 } /* ng_h4_disconnect */
739 
740 /*
741  * Remove this node. The does the netgraph portion of the shutdown.
742  * This should only be called indirectly from ng_h4_close().
743  */
744 
745 static int
746 ng_h4_shutdown(node_p node)
747 {
748 	ng_h4_info_p	sc = (ng_h4_info_p) NG_NODE_PRIVATE(node);
749 
750 	NG_H4_LOCK(sc);
751 
752 	if (!sc->dying) {
753 		NG_H4_UNLOCK(sc);
754 
755 		NG_NODE_REVIVE(node);	/* we will persist */
756 
757 		return (EOPNOTSUPP);
758 	}
759 
760 	NG_H4_UNLOCK(sc);
761 
762 	NG_NODE_SET_PRIVATE(node, NULL);
763 
764 	_IF_DRAIN(&sc->outq);
765 
766 	NG_NODE_UNREF(node);
767 	mtx_destroy(&sc->outq.ifq_mtx);
768 	bzero(sc, sizeof(*sc));
769 	FREE(sc, M_NETGRAPH_H4);
770 
771 	return (0);
772 } /* ng_h4_shutdown */
773 
774 /*
775  * Receive incoming data from Netgraph system. Put it on our
776  * output queue and start output if necessary.
777  */
778 
779 static int
780 ng_h4_rcvdata(hook_p hook, item_p item)
781 {
782 	ng_h4_info_p	 sc = (ng_h4_info_p)NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
783 	struct mbuf	*m = NULL;
784 	int		 qlen;
785 
786 	if (sc == NULL)
787 		return (EHOSTDOWN);
788 
789 	if (hook != sc->hook)
790 		panic("%s: hook != sc->hook\n", __func__);
791 
792 	NGI_GET_M(item, m);
793 	NG_FREE_ITEM(item);
794 
795 	NG_H4_LOCK(sc);
796 
797 	if (_IF_QFULL(&sc->outq)) {
798 		NG_H4_ERR("%s: %s - dropping mbuf, len=%d\n", __func__,
799 			NG_NODE_NAME(sc->node), m->m_pkthdr.len);
800 
801 		NG_H4_STAT_OERROR(sc->stat);
802 		_IF_DROP(&sc->outq);
803 
804 		NG_H4_UNLOCK(sc);
805 
806 		NG_FREE_M(m);
807 
808 		return (ENOBUFS);
809 	}
810 
811 	NG_H4_INFO("%s: %s - queue mbuf, len=%d\n", __func__,
812 		NG_NODE_NAME(sc->node), m->m_pkthdr.len);
813 
814 	_IF_ENQUEUE(&sc->outq, m);
815 	qlen = _IF_QLEN(&sc->outq);
816 
817 	NG_H4_UNLOCK(sc);
818 
819 	/*
820 	 * If qlen > 1, then we should already have a scheduled callout
821 	 */
822 
823 	if (qlen == 1) {
824 		mtx_lock(&Giant);
825 		ng_h4_start(sc->tp);
826 		mtx_unlock(&Giant);
827 	}
828 
829 	return (0);
830 } /* ng_h4_rcvdata */
831 
832 /*
833  * Receive control message
834  */
835 
836 static int
837 ng_h4_rcvmsg(node_p node, item_p item, hook_p lasthook)
838 {
839 	ng_h4_info_p	 sc = (ng_h4_info_p) NG_NODE_PRIVATE(node);
840 	struct ng_mesg	*msg = NULL, *resp = NULL;
841 	int		 error = 0;
842 
843 	if (sc == NULL)
844 		return (EHOSTDOWN);
845 
846 	NGI_GET_MSG(item, msg);
847 	NG_H4_LOCK(sc);
848 
849 	switch (msg->header.typecookie) {
850 	case NGM_GENERIC_COOKIE:
851 		switch (msg->header.cmd) {
852 		case NGM_TEXT_STATUS:
853 			NG_MKRESPONSE(resp, msg, NG_TEXTRESPONSE, M_WAITOK | M_NULLOK);
854 			if (resp == NULL)
855 				error = ENOMEM;
856 			else
857 				snprintf(resp->data, NG_TEXTRESPONSE,
858 					"Hook: %s\n"   \
859 					"Debug: %d\n"  \
860 					"State: %d\n"  \
861 					"Queue: [have:%d,max:%d]\n" \
862 					"Input: [got:%d,want:%d]",
863 					(sc->hook != NULL)? NG_H4_HOOK : "",
864 					sc->debug,
865 					sc->state,
866 					_IF_QLEN(&sc->outq),
867 					sc->outq.ifq_maxlen,
868 					sc->got,
869 					sc->want);
870 			break;
871 
872 		default:
873 			error = EINVAL;
874 			break;
875 		}
876 		break;
877 
878 	case NGM_H4_COOKIE:
879 		switch (msg->header.cmd) {
880 		case NGM_H4_NODE_RESET:
881 			_IF_DRAIN(&sc->outq);
882 			sc->state = NG_H4_W4_PKT_IND;
883 			sc->want = 1;
884 			sc->got = 0;
885 			break;
886 
887 		case NGM_H4_NODE_GET_STATE:
888 			NG_MKRESPONSE(resp, msg, sizeof(ng_h4_node_state_ep),
889 				M_WAITOK | M_NULLOK);
890 			if (resp == NULL)
891 				error = ENOMEM;
892 			else
893 				*((ng_h4_node_state_ep *)(resp->data)) =
894 					sc->state;
895 			break;
896 
897 		case NGM_H4_NODE_GET_DEBUG:
898 			NG_MKRESPONSE(resp, msg, sizeof(ng_h4_node_debug_ep),
899 				M_WAITOK | M_NULLOK);
900 			if (resp == NULL)
901 				error = ENOMEM;
902 			else
903 				*((ng_h4_node_debug_ep *)(resp->data)) =
904 					sc->debug;
905 			break;
906 
907 		case NGM_H4_NODE_SET_DEBUG:
908 			if (msg->header.arglen != sizeof(ng_h4_node_debug_ep))
909 				error = EMSGSIZE;
910 			else
911 				sc->debug =
912 					*((ng_h4_node_debug_ep *)(msg->data));
913 			break;
914 
915 		case NGM_H4_NODE_GET_QLEN:
916 			NG_MKRESPONSE(resp, msg, sizeof(ng_h4_node_qlen_ep),
917 				M_WAITOK | M_NULLOK);
918 			if (resp == NULL)
919 				error = ENOMEM;
920 			else
921 				*((ng_h4_node_qlen_ep *)(resp->data)) =
922 					sc->outq.ifq_maxlen;
923 			break;
924 
925 		case NGM_H4_NODE_SET_QLEN:
926 			if (msg->header.arglen != sizeof(ng_h4_node_qlen_ep))
927 				error = EMSGSIZE;
928 			else if (*((ng_h4_node_qlen_ep *)(msg->data)) <= 0)
929 				error = EINVAL;
930 			else
931 				IFQ_SET_MAXLEN(&sc->outq,
932 					*((ng_h4_node_qlen_ep *)(msg->data)));
933 			break;
934 
935 		case NGM_H4_NODE_GET_STAT:
936 			NG_MKRESPONSE(resp, msg, sizeof(ng_h4_node_stat_ep),
937 				M_WAITOK | M_NULLOK);
938 			if (resp == NULL)
939 				error = ENOMEM;
940 			else
941 				bcopy(&sc->stat, resp->data,
942 					sizeof(ng_h4_node_stat_ep));
943 			break;
944 
945 		case NGM_H4_NODE_RESET_STAT:
946 			NG_H4_STAT_RESET(sc->stat);
947 			break;
948 
949 		default:
950 			error = EINVAL;
951 			break;
952 		}
953 		break;
954 
955 	default:
956 		error = EINVAL;
957 		break;
958 	}
959 
960 	NG_H4_UNLOCK(sc);
961 
962 	NG_RESPOND_MSG(error, node, item, resp);
963 	NG_FREE_MSG(msg);
964 
965 	return (error);
966 } /* ng_h4_rcvmsg */
967 
968 /*
969  * Timeout processing function.
970  * We still have data to output to the device, so try sending more.
971  */
972 
973 static void
974 ng_h4_process_timeout(node_p node, hook_p hook, void *arg1, int arg2)
975 {
976 	ng_h4_info_p	sc = (ng_h4_info_p) NG_NODE_PRIVATE(node);
977 
978 	mtx_lock(&Giant);
979 	ng_h4_start(sc->tp);
980 	mtx_unlock(&Giant);
981 } /* ng_h4_process_timeout */
982 
983 /*
984  * Handle loading and unloading for this node type
985  */
986 
987 static int
988 ng_h4_mod_event(module_t mod, int event, void *data)
989 {
990 	static int	ng_h4_ldisc;
991 	int		error = 0;
992 
993 	switch (event) {
994 	case MOD_LOAD:
995 		/* Register line discipline */
996 		mtx_lock(&Giant);
997 		ng_h4_ldisc = ldisc_register(H4DISC, &ng_h4_disc);
998 		mtx_unlock(&Giant);
999 
1000 		if (ng_h4_ldisc < 0) {
1001 			printf("%s: can't register H4 line discipline\n",
1002 				__func__);
1003 			error = EIO;
1004 		}
1005 		break;
1006 
1007 	case MOD_UNLOAD:
1008 		/* Unregister line discipline */
1009 		mtx_lock(&Giant);
1010 		ldisc_deregister(ng_h4_ldisc);
1011 		mtx_unlock(&Giant);
1012 		break;
1013 
1014 	default:
1015 		error = EOPNOTSUPP;
1016 		break;
1017 	}
1018 
1019 	return (error);
1020 } /* ng_h4_mod_event */
1021 
1022