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/ioccom.h>
51 #include <sys/malloc.h>
52 #include <sys/mbuf.h>
53 #include <sys/priv.h>
54 #include <sys/socket.h>
55 #include <sys/tty.h>
56 #include <sys/ttycom.h>
57 #include <net/if.h>
58 #include <net/if_var.h>
59 #include "ng_message.h"
60 #include "netgraph.h"
61 #include "ng_parse.h"
62 #include "bluetooth/include/ng_bluetooth.h"
63 #include "bluetooth/include/ng_hci.h"
64 #include "bluetooth/include/ng_h4.h"
65 #include "bluetooth/drivers/h4/ng_h4_var.h"
66 #include "bluetooth/drivers/h4/ng_h4_prse.h"
67 
68 /*****************************************************************************
69  *****************************************************************************
70  ** This node implements a Bluetooth HCI UART transport layer as per chapter
71  ** H4 of the Bluetooth Specification Book v1.1. It is a terminal line
72  ** discipline that is also a netgraph node. Installing this line discipline
73  ** on a terminal device instantiates a new netgraph node of this type, which
74  ** allows access to the device via the "hook" hook of the node.
75  **
76  ** Once the line discipline is installed, you can find out the name of the
77  ** corresponding netgraph node via a NGIOCGINFO ioctl().
78  *****************************************************************************
79  *****************************************************************************/
80 
81 /* MALLOC define */
82 #ifndef NG_SEPARATE_MALLOC
83 MALLOC_DEFINE(M_NETGRAPH_H4, "netgraph_h4", "Netgraph Bluetooth H4 node");
84 #else
85 #define M_NETGRAPH_H4 M_NETGRAPH
86 #endif /* NG_SEPARATE_MALLOC */
87 
88 /* Line discipline methods */
89 static int	ng_h4_open	(struct cdev *, struct tty *);
90 static int	ng_h4_close	(struct tty *, int);
91 static int	ng_h4_read	(struct tty *, struct uio *, int);
92 static int	ng_h4_write	(struct tty *, struct uio *, int);
93 static int	ng_h4_input	(int, struct tty *);
94 static int	ng_h4_start	(struct tty *);
95 static int	ng_h4_ioctl	(struct tty *, u_long, caddr_t,
96 					int, struct thread *);
97 
98 /* Line discipline descriptor */
99 static struct linesw		ng_h4_disc = {
100 	ng_h4_open,		/* open */
101 	ng_h4_close,		/* close */
102 	ng_h4_read,		/* read */
103 	ng_h4_write,		/* write */
104 	ng_h4_ioctl,		/* ioctl */
105 	ng_h4_input,		/* input */
106 	ng_h4_start,		/* start */
107 	ttymodem		/* modem */
108 };
109 
110 /* Netgraph methods */
111 static ng_constructor_t		ng_h4_constructor;
112 static ng_rcvmsg_t		ng_h4_rcvmsg;
113 static ng_shutdown_t		ng_h4_shutdown;
114 static ng_newhook_t		ng_h4_newhook;
115 static ng_connect_t		ng_h4_connect;
116 static ng_rcvdata_t		ng_h4_rcvdata;
117 static ng_disconnect_t		ng_h4_disconnect;
118 
119 /* Other stuff */
120 static void	ng_h4_process_timeout	(node_p, hook_p, void *, int);
121 static int	ng_h4_mod_event		(module_t, int, void *);
122 
123 /* Netgraph node type descriptor */
124 static struct ng_type		typestruct = {
125 	.version =	NG_ABI_VERSION,
126 	.name =		NG_H4_NODE_TYPE,
127 	.mod_event =	ng_h4_mod_event,
128 	.constructor =	ng_h4_constructor,
129 	.rcvmsg =	ng_h4_rcvmsg,
130 	.shutdown =	ng_h4_shutdown,
131 	.newhook =	ng_h4_newhook,
132 	.connect =	ng_h4_connect,
133 	.rcvdata =	ng_h4_rcvdata,
134 	.disconnect =	ng_h4_disconnect,
135 	.cmdlist =	ng_h4_cmdlist
136 };
137 NETGRAPH_INIT(h4, &typestruct);
138 MODULE_VERSION(ng_h4, NG_BLUETOOTH_VERSION);
139 
140 static int	ng_h4_node = 0;
141 
142 /*****************************************************************************
143  *****************************************************************************
144  **			    Line discipline methods
145  *****************************************************************************
146  *****************************************************************************/
147 
148 /*
149  * Set our line discipline on the tty.
150  */
151 
152 static int
153 ng_h4_open(struct cdev *dev, struct tty *tp)
154 {
155 	struct thread	*td = curthread;
156 	char		 name[NG_NODESIZ];
157 	ng_h4_info_p	 sc = NULL;
158 	int		 error;
159 
160 	/* Super-user only */
161 	error = priv_check(td, PRIV_NETGRAPH_TTY); /* XXX */
162 	if (error != 0)
163 		return (error);
164 
165 	/* Initialize private struct */
166 	MALLOC(sc, ng_h4_info_p, sizeof(*sc), M_NETGRAPH_H4, M_WAITOK | M_NULLOK | M_ZERO);
167 	if (sc == NULL)
168 		return (ENOMEM);
169 
170 	sc->tp = tp;
171 	sc->debug = NG_H4_WARN_LEVEL;
172 
173 	sc->state = NG_H4_W4_PKT_IND;
174 	sc->want = 1;
175 	sc->got = 0;
176 
177 	mtx_init(&sc->outq.ifq_mtx, "ng_h4 node+queue", NULL, MTX_DEF);
178 	IFQ_SET_MAXLEN(&sc->outq, NG_H4_DEFAULTQLEN);
179 	ng_callout_init(&sc->timo);
180 
181 	NG_H4_LOCK(sc);
182 
183 	/* Setup netgraph node */
184 	error = ng_make_node_common(&typestruct, &sc->node);
185 	if (error != 0) {
186 		NG_H4_UNLOCK(sc);
187 
188 		printf("%s: Unable to create new node!\n", __func__);
189 
190 		mtx_destroy(&sc->outq.ifq_mtx);
191 		bzero(sc, sizeof(*sc));
192 		FREE(sc, M_NETGRAPH_H4);
193 
194 		return (error);
195 	}
196 
197 	/* Assign node its name */
198 	snprintf(name, sizeof(name), "%s%d", typestruct.name, ng_h4_node ++);
199 
200 	error = ng_name_node(sc->node, name);
201 	if (error != 0) {
202 		NG_H4_UNLOCK(sc);
203 
204 		printf("%s: %s - node name exists?\n", __func__, name);
205 
206 		NG_NODE_UNREF(sc->node);
207 		mtx_destroy(&sc->outq.ifq_mtx);
208 		bzero(sc, sizeof(*sc));
209 		FREE(sc, M_NETGRAPH_H4);
210 
211 		return (error);
212 	}
213 
214 	/* Set back pointers */
215 	NG_NODE_SET_PRIVATE(sc->node, sc);
216 	tp->t_lsc = (caddr_t) sc;
217 
218 	/* The node has to be a WRITER because data can change node status */
219 	NG_NODE_FORCE_WRITER(sc->node);
220 
221 	/*
222 	 * Pre-allocate cblocks to the an appropriate amount.
223 	 * I'm not sure what is appropriate.
224 	 */
225 
226 	ttyflush(tp, FREAD | FWRITE);
227 	clist_alloc_cblocks(&tp->t_canq, 0, 0);
228 	clist_alloc_cblocks(&tp->t_rawq, 0, 0);
229 	clist_alloc_cblocks(&tp->t_outq,
230 		MLEN + NG_H4_HIWATER, MLEN + NG_H4_HIWATER);
231 
232 	NG_H4_UNLOCK(sc);
233 
234 	return (error);
235 } /* ng_h4_open */
236 
237 /*
238  * Line specific close routine, called from device close routine
239  * and from ttioctl. This causes the node to be destroyed as well.
240  */
241 
242 static int
243 ng_h4_close(struct tty *tp, int flag)
244 {
245 	ng_h4_info_p	sc = (ng_h4_info_p) tp->t_lsc;
246 
247 	ttyflush(tp, FREAD | FWRITE);
248 	clist_free_cblocks(&tp->t_outq);
249 
250 	if (sc != NULL) {
251 		NG_H4_LOCK(sc);
252 
253 		if (callout_pending(&sc->timo))
254 			ng_uncallout(&sc->timo, sc->node);
255 
256 		tp->t_lsc = NULL;
257 		sc->dying = 1;
258 
259 		NG_H4_UNLOCK(sc);
260 
261 		ng_rmnode_self(sc->node);
262 	}
263 
264 	return (0);
265 } /* ng_h4_close */
266 
267 /*
268  * Once the device has been turned into a node, we don't allow reading.
269  */
270 
271 static int
272 ng_h4_read(struct tty *tp, struct uio *uio, int flag)
273 {
274 	return (EIO);
275 } /* ng_h4_read */
276 
277 /*
278  * Once the device has been turned into a node, we don't allow writing.
279  */
280 
281 static int
282 ng_h4_write(struct tty *tp, struct uio *uio, int flag)
283 {
284 	return (EIO);
285 } /* ng_h4_write */
286 
287 /*
288  * We implement the NGIOCGINFO ioctl() defined in ng_message.h.
289  */
290 
291 static int
292 ng_h4_ioctl(struct tty *tp, u_long cmd, caddr_t data, int flag,
293 		struct thread *td)
294 {
295 	ng_h4_info_p	sc = (ng_h4_info_p) tp->t_lsc;
296 	int		error = 0;
297 
298 	if (sc == NULL)
299 		return (ENXIO);
300 
301 	NG_H4_LOCK(sc);
302 
303 	switch (cmd) {
304 	case NGIOCGINFO:
305 #undef	NI
306 #define NI(x)	((struct nodeinfo *)(x))
307 
308 		bzero(data, sizeof(*NI(data)));
309 
310 		if (NG_NODE_HAS_NAME(sc->node))
311 			strncpy(NI(data)->name, NG_NODE_NAME(sc->node),
312 				sizeof(NI(data)->name) - 1);
313 
314 		strncpy(NI(data)->type, sc->node->nd_type->name,
315 			sizeof(NI(data)->type) - 1);
316 
317 		NI(data)->id = (u_int32_t) ng_node2ID(sc->node);
318 		NI(data)->hooks = NG_NODE_NUMHOOKS(sc->node);
319 		break;
320 
321 	default:
322 		error = ENOIOCTL;
323 		break;
324 	}
325 
326 	NG_H4_UNLOCK(sc);
327 
328 	return (error);
329 } /* ng_h4_ioctl */
330 
331 /*
332  * Receive data coming from the device. We get one character at a time, which
333  * is kindof silly.
334  */
335 
336 static int
337 ng_h4_input(int c, struct tty *tp)
338 {
339 	ng_h4_info_p	sc = (ng_h4_info_p) tp->t_lsc;
340 
341 	if (sc == NULL || tp != sc->tp ||
342 	    sc->node == NULL || NG_NODE_NOT_VALID(sc->node))
343 		return (0);
344 
345 	NG_H4_LOCK(sc);
346 
347 	/* Check for error conditions */
348 	if ((tp->t_state & TS_CONNECTED) == 0) {
349 		NG_H4_INFO("%s: %s - no carrier\n", __func__,
350 			NG_NODE_NAME(sc->node));
351 
352 		sc->state = NG_H4_W4_PKT_IND;
353 		sc->want = 1;
354 		sc->got = 0;
355 
356 		NG_H4_UNLOCK(sc);
357 
358 		return (0); /* XXX Loss of synchronization here! */
359 	}
360 
361 	/* Check for framing error or overrun on this char */
362 	if (c & TTY_ERRORMASK) {
363 		NG_H4_ERR("%s: %s - line error %#x, c=%#x\n", __func__,
364 			NG_NODE_NAME(sc->node), c & TTY_ERRORMASK,
365 			c & TTY_CHARMASK);
366 
367 		NG_H4_STAT_IERROR(sc->stat);
368 
369 		sc->state = NG_H4_W4_PKT_IND;
370 		sc->want = 1;
371 		sc->got = 0;
372 
373 		NG_H4_UNLOCK(sc);
374 
375 		return (0); /* XXX Loss of synchronization here! */
376 	}
377 
378 	NG_H4_STAT_BYTES_RECV(sc->stat, 1);
379 
380 	/* Append char to mbuf */
381 	if (sc->got >= sizeof(sc->ibuf)) {
382 		NG_H4_ALERT("%s: %s - input buffer overflow, c=%#x, got=%d\n",
383 			__func__, NG_NODE_NAME(sc->node), c & TTY_CHARMASK,
384 			sc->got);
385 
386 		NG_H4_STAT_IERROR(sc->stat);
387 
388 		sc->state = NG_H4_W4_PKT_IND;
389 		sc->want = 1;
390 		sc->got = 0;
391 
392 		NG_H4_UNLOCK(sc);
393 
394 		return (0); /* XXX Loss of synchronization here! */
395 	}
396 
397 	sc->ibuf[sc->got ++] = (c & TTY_CHARMASK);
398 
399 	NG_H4_INFO("%s: %s - got char %#x, want=%d, got=%d\n", __func__,
400 		NG_NODE_NAME(sc->node), c, sc->want, sc->got);
401 
402 	if (sc->got < sc->want) {
403 		NG_H4_UNLOCK(sc);
404 
405 		return (0); /* Wait for more */
406 	}
407 
408 	switch (sc->state) {
409 	/* Got packet indicator */
410 	case NG_H4_W4_PKT_IND:
411 		NG_H4_INFO("%s: %s - got packet indicator %#x\n", __func__,
412 			NG_NODE_NAME(sc->node), sc->ibuf[0]);
413 
414 		sc->state = NG_H4_W4_PKT_HDR;
415 
416 		/*
417 		 * Since packet indicator included in the packet header
418 		 * just set sc->want to sizeof(packet header).
419 		 */
420 
421 		switch (sc->ibuf[0]) {
422 		case NG_HCI_ACL_DATA_PKT:
423 			sc->want = sizeof(ng_hci_acldata_pkt_t);
424 			break;
425 
426 		case NG_HCI_SCO_DATA_PKT:
427 			sc->want = sizeof(ng_hci_scodata_pkt_t);
428 			break;
429 
430 		case NG_HCI_EVENT_PKT:
431 			sc->want = sizeof(ng_hci_event_pkt_t);
432 			break;
433 
434 		default:
435 			NG_H4_WARN("%s: %s - ignoring unknown packet " \
436 				"type=%#x\n", __func__, NG_NODE_NAME(sc->node),
437 				sc->ibuf[0]);
438 
439 			NG_H4_STAT_IERROR(sc->stat);
440 
441 			sc->state = NG_H4_W4_PKT_IND;
442 			sc->want = 1;
443 			sc->got = 0;
444 			break;
445 		}
446 		break;
447 
448 	/* Got packet header */
449 	case NG_H4_W4_PKT_HDR:
450 		sc->state = NG_H4_W4_PKT_DATA;
451 
452 		switch (sc->ibuf[0]) {
453 		case NG_HCI_ACL_DATA_PKT:
454 			c = le16toh(((ng_hci_acldata_pkt_t *)
455 				(sc->ibuf))->length);
456 			break;
457 
458 		case NG_HCI_SCO_DATA_PKT:
459 			c = ((ng_hci_scodata_pkt_t *)(sc->ibuf))->length;
460 			break;
461 
462 		case NG_HCI_EVENT_PKT:
463 			c = ((ng_hci_event_pkt_t *)(sc->ibuf))->length;
464 			break;
465 
466 		default:
467 			KASSERT((0), ("Invalid packet type=%#x\n",
468 				sc->ibuf[0]));
469 			break;
470 		}
471 
472 		NG_H4_INFO("%s: %s - got packet header, packet type=%#x, " \
473 			"packet size=%d, payload size=%d\n", __func__,
474 			NG_NODE_NAME(sc->node), sc->ibuf[0], sc->got, c);
475 
476 		if (c > 0) {
477 			sc->want += c;
478 
479 			/*
480 			 * Try to prevent possible buffer overrun
481 			 *
482 			 * XXX I'm *really* confused here. It turns out
483 			 * that Xircom card sends us packets with length
484 			 * greater then 512 bytes! This is greater then
485 			 * our old receive buffer (ibuf) size. In the same
486 			 * time the card demands from us *not* to send
487 			 * packets greater then 192 bytes. Weird! How the
488 			 * hell i should know how big *receive* buffer
489 			 * should be? For now increase receiving buffer
490 			 * size to 1K and add the following check.
491 			 */
492 
493 			if (sc->want >= sizeof(sc->ibuf)) {
494 				int	b;
495 
496 				NG_H4_ALERT("%s: %s - packet too big for " \
497 					"buffer, type=%#x, got=%d, want=%d, " \
498 					"length=%d\n", __func__,
499 					NG_NODE_NAME(sc->node), sc->ibuf[0],
500 					sc->got, sc->want, c);
501 
502 				NG_H4_ALERT("Packet header:\n");
503 				for (b = 0; b < sc->got; b++)
504 					NG_H4_ALERT("%#x ", sc->ibuf[b]);
505 				NG_H4_ALERT("\n");
506 
507 				/* Reset state */
508 				NG_H4_STAT_IERROR(sc->stat);
509 
510 				sc->state = NG_H4_W4_PKT_IND;
511 				sc->want = 1;
512 				sc->got = 0;
513 			}
514 
515 			break;
516 		}
517 
518 		/* else FALLTHROUGH and deliver frame */
519 		/* XXX Is this true? Should we deliver empty frame? */
520 
521 	/* Got packet data */
522 	case NG_H4_W4_PKT_DATA:
523 		NG_H4_INFO("%s: %s - got full packet, packet type=%#x, " \
524 			"packet size=%d\n", __func__,
525 			NG_NODE_NAME(sc->node), sc->ibuf[0], sc->got);
526 
527 		if (sc->hook != NULL && NG_HOOK_IS_VALID(sc->hook)) {
528 			struct mbuf	*m = NULL;
529 
530 			MGETHDR(m, MB_DONTWAIT, MT_DATA);
531 			if (m != NULL) {
532 				m->m_pkthdr.len = 0;
533 
534 				/* XXX m_copyback() is stupid */
535 				m->m_len = min(MHLEN, sc->got);
536 
537 				m_copyback(m, 0, sc->got, sc->ibuf);
538 				NG_SEND_DATA_ONLY(c, sc->hook, m);
539 			} else {
540 				NG_H4_ERR("%s: %s - could not get mbuf\n",
541 					__func__, NG_NODE_NAME(sc->node));
542 
543 				NG_H4_STAT_IERROR(sc->stat);
544 			}
545 		}
546 
547 		sc->state = NG_H4_W4_PKT_IND;
548 		sc->want = 1;
549 		sc->got = 0;
550 
551 		NG_H4_STAT_PCKTS_RECV(sc->stat);
552 		break;
553 
554 	default:
555 		KASSERT((0), ("Invalid H4 node state=%d", sc->state));
556 		break;
557 	}
558 
559 	NG_H4_UNLOCK(sc);
560 
561 	return (0);
562 } /* ng_h4_input */
563 
564 /*
565  * This is called when the device driver is ready for more output. Called from
566  * tty system.
567  */
568 
569 static int
570 ng_h4_start(struct tty *tp)
571 {
572 	ng_h4_info_p	 sc = (ng_h4_info_p) tp->t_lsc;
573 	struct mbuf	*m = NULL;
574 	int		 size;
575 
576 	if (sc == NULL || tp != sc->tp ||
577 	    sc->node == NULL || NG_NODE_NOT_VALID(sc->node))
578 		return (0);
579 
580 #if 0
581 	while (tp->t_outq.c_cc < NG_H4_HIWATER) { /* XXX 2.2 specific ? */
582 #else
583 	while (1) {
584 #endif
585 		/* Remove first mbuf from queue */
586 		IF_DEQUEUE(&sc->outq, m);
587 		if (m == NULL)
588 			break;
589 
590 		/* Send as much of it as possible */
591 		while (m != NULL) {
592 			size = m->m_len - b_to_q(mtod(m, u_char *),
593 					m->m_len, &tp->t_outq);
594 
595 			NG_H4_LOCK(sc);
596 			NG_H4_STAT_BYTES_SENT(sc->stat, size);
597 			NG_H4_UNLOCK(sc);
598 
599 			m->m_data += size;
600 			m->m_len -= size;
601 			if (m->m_len > 0)
602 				break;	/* device can't take no more */
603 
604 			m = m_free(m);
605 		}
606 
607 		/* Put remainder of mbuf chain (if any) back on queue */
608 		if (m != NULL) {
609 			IF_PREPEND(&sc->outq, m);
610 			break;
611 		}
612 
613 		/* Full packet has been sent */
614 		NG_H4_LOCK(sc);
615 		NG_H4_STAT_PCKTS_SENT(sc->stat);
616 		NG_H4_UNLOCK(sc);
617 	}
618 
619 	/*
620 	 * Call output process whether or not there is any output. We are
621 	 * being called in lieu of ttstart and must do what it would.
622 	 */
623 
624 	tt_oproc(sc->tp);
625 
626 	/*
627 	 * This timeout is needed for operation on a pseudo-tty, because the
628 	 * pty code doesn't call pppstart after it has drained the t_outq.
629 	 */
630 
631 	NG_H4_LOCK(sc);
632 
633 	if (!IFQ_IS_EMPTY(&sc->outq) && !callout_pending(&sc->timo))
634 		ng_callout(&sc->timo, sc->node, NULL, 1,
635 			ng_h4_process_timeout, NULL, 0);
636 
637 	NG_H4_UNLOCK(sc);
638 
639 	return (0);
640 } /* ng_h4_start */
641 
642 /*****************************************************************************
643  *****************************************************************************
644  **			    Netgraph node methods
645  *****************************************************************************
646  *****************************************************************************/
647 
648 /*
649  * Initialize a new node of this type. We only allow nodes to be created as
650  * a result of setting the line discipline on a tty, so always return an error
651  * if not.
652  */
653 
654 static int
655 ng_h4_constructor(node_p node)
656 {
657 	return (EOPNOTSUPP);
658 } /* ng_h4_constructor */
659 
660 /*
661  * Add a new hook. There can only be one.
662  */
663 
664 static int
665 ng_h4_newhook(node_p node, hook_p hook, const char *name)
666 {
667 	ng_h4_info_p	sc = (ng_h4_info_p) NG_NODE_PRIVATE(node);
668 
669 	if (strcmp(name, NG_H4_HOOK) != 0)
670 		return (EINVAL);
671 
672 	NG_H4_LOCK(sc);
673 
674 	if (sc->hook != NULL) {
675 		NG_H4_UNLOCK(sc);
676 		return (EISCONN);
677 	}
678 	sc->hook = hook;
679 
680 	NG_H4_UNLOCK(sc);
681 
682 	return (0);
683 } /* ng_h4_newhook */
684 
685 /*
686  * Connect hook. Just say yes.
687  */
688 
689 static int
690 ng_h4_connect(hook_p hook)
691 {
692 	ng_h4_info_p	sc = (ng_h4_info_p) NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
693 
694 	if (hook != sc->hook)
695 		panic("%s: hook != sc->hook\n", __func__);
696 
697 	NG_HOOK_FORCE_QUEUE(NG_HOOK_PEER(hook));
698 	NG_HOOK_FORCE_QUEUE(hook);
699 
700 	return (0);
701 } /* ng_h4_connect */
702 
703 /*
704  * Disconnect the hook
705  */
706 
707 static int
708 ng_h4_disconnect(hook_p hook)
709 {
710 	ng_h4_info_p	sc = (ng_h4_info_p) NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
711 
712 	/*
713 	 * We need to check for sc != NULL because we can be called from
714 	 * ng_h4_close() via ng_rmnode_self()
715 	 */
716 
717 	if (sc != NULL) {
718 		if (hook != sc->hook)
719 			panic("%s: hook != sc->hook\n", __func__);
720 
721 		NG_H4_LOCK(sc);
722 
723 		/* XXX do we have to untimeout and drain out queue? */
724 		if (callout_pending(&sc->timo))
725 			ng_uncallout(&sc->timo, sc->node);
726 
727 		_IF_DRAIN(&sc->outq);
728 
729 		sc->state = NG_H4_W4_PKT_IND;
730 		sc->want = 1;
731 		sc->got = 0;
732 
733 		sc->hook = NULL;
734 
735 		NG_H4_UNLOCK(sc);
736 	}
737 
738 	return (0);
739 } /* ng_h4_disconnect */
740 
741 /*
742  * Remove this node. The does the netgraph portion of the shutdown.
743  * This should only be called indirectly from ng_h4_close().
744  */
745 
746 static int
747 ng_h4_shutdown(node_p node)
748 {
749 	ng_h4_info_p	sc = (ng_h4_info_p) NG_NODE_PRIVATE(node);
750 
751 	NG_H4_LOCK(sc);
752 
753 	if (!sc->dying) {
754 		NG_H4_UNLOCK(sc);
755 
756 		NG_NODE_REVIVE(node);	/* we will persist */
757 
758 		return (EOPNOTSUPP);
759 	}
760 
761 	NG_H4_UNLOCK(sc);
762 
763 	NG_NODE_SET_PRIVATE(node, NULL);
764 
765 	_IF_DRAIN(&sc->outq);
766 
767 	NG_NODE_UNREF(node);
768 	mtx_destroy(&sc->outq.ifq_mtx);
769 	bzero(sc, sizeof(*sc));
770 	FREE(sc, M_NETGRAPH_H4);
771 
772 	return (0);
773 } /* ng_h4_shutdown */
774 
775 /*
776  * Receive incoming data from Netgraph system. Put it on our
777  * output queue and start output if necessary.
778  */
779 
780 static int
781 ng_h4_rcvdata(hook_p hook, item_p item)
782 {
783 	ng_h4_info_p	 sc = (ng_h4_info_p)NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
784 	struct mbuf	*m = NULL;
785 	int		 qlen;
786 
787 	if (sc == NULL)
788 		return (EHOSTDOWN);
789 
790 	if (hook != sc->hook)
791 		panic("%s: hook != sc->hook\n", __func__);
792 
793 	NGI_GET_M(item, m);
794 	NG_FREE_ITEM(item);
795 
796 	NG_H4_LOCK(sc);
797 
798 	if (_IF_QFULL(&sc->outq)) {
799 		NG_H4_ERR("%s: %s - dropping mbuf, len=%d\n", __func__,
800 			NG_NODE_NAME(sc->node), m->m_pkthdr.len);
801 
802 		NG_H4_STAT_OERROR(sc->stat);
803 		_IF_DROP(&sc->outq);
804 
805 		NG_H4_UNLOCK(sc);
806 
807 		NG_FREE_M(m);
808 
809 		return (ENOBUFS);
810 	}
811 
812 	NG_H4_INFO("%s: %s - queue mbuf, len=%d\n", __func__,
813 		NG_NODE_NAME(sc->node), m->m_pkthdr.len);
814 
815 	_IF_ENQUEUE(&sc->outq, m);
816 	qlen = _IF_QLEN(&sc->outq);
817 
818 	NG_H4_UNLOCK(sc);
819 
820 	/*
821 	 * If qlen > 1, then we should already have a scheduled callout
822 	 */
823 
824 	if (qlen == 1) {
825 		mtx_lock(&Giant);
826 		ng_h4_start(sc->tp);
827 		mtx_unlock(&Giant);
828 	}
829 
830 	return (0);
831 } /* ng_h4_rcvdata */
832 
833 /*
834  * Receive control message
835  */
836 
837 static int
838 ng_h4_rcvmsg(node_p node, item_p item, hook_p lasthook)
839 {
840 	ng_h4_info_p	 sc = (ng_h4_info_p) NG_NODE_PRIVATE(node);
841 	struct ng_mesg	*msg = NULL, *resp = NULL;
842 	int		 error = 0;
843 
844 	if (sc == NULL)
845 		return (EHOSTDOWN);
846 
847 	NGI_GET_MSG(item, msg);
848 	NG_H4_LOCK(sc);
849 
850 	switch (msg->header.typecookie) {
851 	case NGM_GENERIC_COOKIE:
852 		switch (msg->header.cmd) {
853 		case NGM_TEXT_STATUS:
854 			NG_MKRESPONSE(resp, msg, NG_TEXTRESPONSE, M_WAITOK | M_NULLOK);
855 			if (resp == NULL)
856 				error = ENOMEM;
857 			else
858 				snprintf(resp->data, NG_TEXTRESPONSE,
859 					"Hook: %s\n"   \
860 					"Debug: %d\n"  \
861 					"State: %d\n"  \
862 					"Queue: [have:%d,max:%d]\n" \
863 					"Input: [got:%d,want:%d]",
864 					(sc->hook != NULL)? NG_H4_HOOK : "",
865 					sc->debug,
866 					sc->state,
867 					_IF_QLEN(&sc->outq),
868 					sc->outq.ifq_maxlen,
869 					sc->got,
870 					sc->want);
871 			break;
872 
873 		default:
874 			error = EINVAL;
875 			break;
876 		}
877 		break;
878 
879 	case NGM_H4_COOKIE:
880 		switch (msg->header.cmd) {
881 		case NGM_H4_NODE_RESET:
882 			_IF_DRAIN(&sc->outq);
883 			sc->state = NG_H4_W4_PKT_IND;
884 			sc->want = 1;
885 			sc->got = 0;
886 			break;
887 
888 		case NGM_H4_NODE_GET_STATE:
889 			NG_MKRESPONSE(resp, msg, sizeof(ng_h4_node_state_ep),
890 				M_WAITOK | M_NULLOK);
891 			if (resp == NULL)
892 				error = ENOMEM;
893 			else
894 				*((ng_h4_node_state_ep *)(resp->data)) =
895 					sc->state;
896 			break;
897 
898 		case NGM_H4_NODE_GET_DEBUG:
899 			NG_MKRESPONSE(resp, msg, sizeof(ng_h4_node_debug_ep),
900 				M_WAITOK | M_NULLOK);
901 			if (resp == NULL)
902 				error = ENOMEM;
903 			else
904 				*((ng_h4_node_debug_ep *)(resp->data)) =
905 					sc->debug;
906 			break;
907 
908 		case NGM_H4_NODE_SET_DEBUG:
909 			if (msg->header.arglen != sizeof(ng_h4_node_debug_ep))
910 				error = EMSGSIZE;
911 			else
912 				sc->debug =
913 					*((ng_h4_node_debug_ep *)(msg->data));
914 			break;
915 
916 		case NGM_H4_NODE_GET_QLEN:
917 			NG_MKRESPONSE(resp, msg, sizeof(ng_h4_node_qlen_ep),
918 				M_WAITOK | M_NULLOK);
919 			if (resp == NULL)
920 				error = ENOMEM;
921 			else
922 				*((ng_h4_node_qlen_ep *)(resp->data)) =
923 					sc->outq.ifq_maxlen;
924 			break;
925 
926 		case NGM_H4_NODE_SET_QLEN:
927 			if (msg->header.arglen != sizeof(ng_h4_node_qlen_ep))
928 				error = EMSGSIZE;
929 			else if (*((ng_h4_node_qlen_ep *)(msg->data)) <= 0)
930 				error = EINVAL;
931 			else
932 				IFQ_SET_MAXLEN(&sc->outq,
933 					*((ng_h4_node_qlen_ep *)(msg->data)));
934 			break;
935 
936 		case NGM_H4_NODE_GET_STAT:
937 			NG_MKRESPONSE(resp, msg, sizeof(ng_h4_node_stat_ep),
938 				M_WAITOK | M_NULLOK);
939 			if (resp == NULL)
940 				error = ENOMEM;
941 			else
942 				bcopy(&sc->stat, resp->data,
943 					sizeof(ng_h4_node_stat_ep));
944 			break;
945 
946 		case NGM_H4_NODE_RESET_STAT:
947 			NG_H4_STAT_RESET(sc->stat);
948 			break;
949 
950 		default:
951 			error = EINVAL;
952 			break;
953 		}
954 		break;
955 
956 	default:
957 		error = EINVAL;
958 		break;
959 	}
960 
961 	NG_H4_UNLOCK(sc);
962 
963 	NG_RESPOND_MSG(error, node, item, resp);
964 	NG_FREE_MSG(msg);
965 
966 	return (error);
967 } /* ng_h4_rcvmsg */
968 
969 /*
970  * Timeout processing function.
971  * We still have data to output to the device, so try sending more.
972  */
973 
974 static void
975 ng_h4_process_timeout(node_p node, hook_p hook, void *arg1, int arg2)
976 {
977 	ng_h4_info_p	sc = (ng_h4_info_p) NG_NODE_PRIVATE(node);
978 
979 	mtx_lock(&Giant);
980 	ng_h4_start(sc->tp);
981 	mtx_unlock(&Giant);
982 } /* ng_h4_process_timeout */
983 
984 /*
985  * Handle loading and unloading for this node type
986  */
987 
988 static int
989 ng_h4_mod_event(module_t mod, int event, void *data)
990 {
991 	static int	ng_h4_ldisc;
992 	int		error = 0;
993 
994 	switch (event) {
995 	case MOD_LOAD:
996 		/* Register line discipline */
997 		mtx_lock(&Giant);
998 		ng_h4_ldisc = ldisc_register(H4DISC, &ng_h4_disc);
999 		mtx_unlock(&Giant);
1000 
1001 		if (ng_h4_ldisc < 0) {
1002 			printf("%s: can't register H4 line discipline\n",
1003 				__func__);
1004 			error = EIO;
1005 		}
1006 		break;
1007 
1008 	case MOD_UNLOAD:
1009 		/* Unregister line discipline */
1010 		mtx_lock(&Giant);
1011 		ldisc_deregister(ng_h4_ldisc);
1012 		mtx_unlock(&Giant);
1013 		break;
1014 
1015 	default:
1016 		error = EOPNOTSUPP;
1017 		break;
1018 	}
1019 
1020 	return (error);
1021 } /* ng_h4_mod_event */
1022 
1023