xref: /freebsd/sys/dev/usb/misc/udbp.c (revision a3cf0ef5a295c885c895fabfd56470c0d1db322d)
1 /*-
2  * Copyright (c) 1996-2000 Whistle Communications, Inc.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of author nor the names of its
14  *    contributors may be used to endorse or promote products derived
15  *    from this software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY NICK HIBMA AND CONTRIBUTORS
18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
21  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27  * POSSIBILITY OF SUCH DAMAGE.
28  *
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 /* Driver for arbitrary double bulk pipe devices.
35  * The driver assumes that there will be the same driver on the other side.
36  *
37  * XXX Some more information on what the framing of the IP packets looks like.
38  *
39  * To take full advantage of bulk transmission, packets should be chosen
40  * between 1k and 5k in size (1k to make sure the sending side starts
41  * streaming, and <5k to avoid overflowing the system with small TDs).
42  */
43 
44 
45 /* probe/attach/detach:
46  *  Connect the driver to the hardware and netgraph
47  *
48  *  The reason we submit a bulk in transfer is that USB does not know about
49  *  interrupts. The bulk transfer continuously polls the device for data.
50  *  While the device has no data available, the device NAKs the TDs. As soon
51  *  as there is data, the transfer happens and the data comes flowing in.
52  *
53  *  In case you were wondering, interrupt transfers happen exactly that way.
54  *  It therefore doesn't make sense to use the interrupt pipe to signal
55  *  'data ready' and then schedule a bulk transfer to fetch it. That would
56  *  incur a 2ms delay at least, without reducing bandwidth requirements.
57  *
58  */
59 
60 #include <sys/stdint.h>
61 #include <sys/stddef.h>
62 #include <sys/param.h>
63 #include <sys/queue.h>
64 #include <sys/types.h>
65 #include <sys/systm.h>
66 #include <sys/kernel.h>
67 #include <sys/bus.h>
68 #include <sys/linker_set.h>
69 #include <sys/module.h>
70 #include <sys/lock.h>
71 #include <sys/mutex.h>
72 #include <sys/condvar.h>
73 #include <sys/sysctl.h>
74 #include <sys/sx.h>
75 #include <sys/unistd.h>
76 #include <sys/callout.h>
77 #include <sys/malloc.h>
78 #include <sys/priv.h>
79 
80 #include <dev/usb/usb.h>
81 #include <dev/usb/usbdi.h>
82 #include <dev/usb/usbdi_util.h>
83 #include "usbdevs.h"
84 
85 #define	USB_DEBUG_VAR udbp_debug
86 #include <dev/usb/usb_debug.h>
87 
88 #include <sys/mbuf.h>
89 
90 #include <netgraph/ng_message.h>
91 #include <netgraph/netgraph.h>
92 #include <netgraph/ng_parse.h>
93 #include <netgraph/bluetooth/include/ng_bluetooth.h>
94 
95 #include <dev/usb/misc/udbp.h>
96 
97 #ifdef USB_DEBUG
98 static int udbp_debug = 0;
99 
100 SYSCTL_NODE(_hw_usb, OID_AUTO, udbp, CTLFLAG_RW, 0, "USB udbp");
101 SYSCTL_INT(_hw_usb_udbp, OID_AUTO, debug, CTLFLAG_RW,
102     &udbp_debug, 0, "udbp debug level");
103 #endif
104 
105 #define	UDBP_TIMEOUT	2000		/* timeout on outbound transfers, in
106 					 * msecs */
107 #define	UDBP_BUFFERSIZE	MCLBYTES	/* maximum number of bytes in one
108 					 * transfer */
109 #define	UDBP_T_WR       0
110 #define	UDBP_T_RD       1
111 #define	UDBP_T_WR_CS    2
112 #define	UDBP_T_RD_CS    3
113 #define	UDBP_T_MAX      4
114 #define	UDBP_Q_MAXLEN   50
115 
116 struct udbp_softc {
117 
118 	struct mtx sc_mtx;
119 	struct ng_bt_mbufq sc_xmitq_hipri;	/* hi-priority transmit queue */
120 	struct ng_bt_mbufq sc_xmitq;	/* low-priority transmit queue */
121 
122 	struct usb_xfer *sc_xfer[UDBP_T_MAX];
123 	node_p	sc_node;		/* back pointer to node */
124 	hook_p	sc_hook;		/* pointer to the hook */
125 	struct mbuf *sc_bulk_in_buffer;
126 
127 	uint32_t sc_packets_in;		/* packets in from downstream */
128 	uint32_t sc_packets_out;	/* packets out towards downstream */
129 
130 	uint8_t	sc_flags;
131 #define	UDBP_FLAG_READ_STALL    0x01	/* read transfer stalled */
132 #define	UDBP_FLAG_WRITE_STALL   0x02	/* write transfer stalled */
133 
134 	uint8_t	sc_name[16];
135 };
136 
137 /* prototypes */
138 
139 static int udbp_modload(module_t mod, int event, void *data);
140 
141 static device_probe_t udbp_probe;
142 static device_attach_t udbp_attach;
143 static device_detach_t udbp_detach;
144 
145 static usb_callback_t udbp_bulk_read_callback;
146 static usb_callback_t udbp_bulk_read_clear_stall_callback;
147 static usb_callback_t udbp_bulk_write_callback;
148 static usb_callback_t udbp_bulk_write_clear_stall_callback;
149 
150 static void	udbp_bulk_read_complete(node_p, hook_p, void *, int);
151 
152 static ng_constructor_t	ng_udbp_constructor;
153 static ng_rcvmsg_t	ng_udbp_rcvmsg;
154 static ng_shutdown_t	ng_udbp_rmnode;
155 static ng_newhook_t	ng_udbp_newhook;
156 static ng_connect_t	ng_udbp_connect;
157 static ng_rcvdata_t	ng_udbp_rcvdata;
158 static ng_disconnect_t	ng_udbp_disconnect;
159 
160 /* Parse type for struct ngudbpstat */
161 static const struct ng_parse_struct_field
162 	ng_udbp_stat_type_fields[] = NG_UDBP_STATS_TYPE_INFO;
163 
164 static const struct ng_parse_type ng_udbp_stat_type = {
165 	&ng_parse_struct_type,
166 	&ng_udbp_stat_type_fields
167 };
168 
169 /* List of commands and how to convert arguments to/from ASCII */
170 static const struct ng_cmdlist ng_udbp_cmdlist[] = {
171 	{
172 		NGM_UDBP_COOKIE,
173 		NGM_UDBP_GET_STATUS,
174 		"getstatus",
175 		NULL,
176 		&ng_udbp_stat_type,
177 	},
178 	{
179 		NGM_UDBP_COOKIE,
180 		NGM_UDBP_SET_FLAG,
181 		"setflag",
182 		&ng_parse_int32_type,
183 		NULL
184 	},
185 	{0}
186 };
187 
188 /* Netgraph node type descriptor */
189 static struct ng_type ng_udbp_typestruct = {
190 	.version = NG_ABI_VERSION,
191 	.name = NG_UDBP_NODE_TYPE,
192 	.constructor = ng_udbp_constructor,
193 	.rcvmsg = ng_udbp_rcvmsg,
194 	.shutdown = ng_udbp_rmnode,
195 	.newhook = ng_udbp_newhook,
196 	.connect = ng_udbp_connect,
197 	.rcvdata = ng_udbp_rcvdata,
198 	.disconnect = ng_udbp_disconnect,
199 	.cmdlist = ng_udbp_cmdlist,
200 };
201 
202 /* USB config */
203 static const struct usb_config udbp_config[UDBP_T_MAX] = {
204 
205 	[UDBP_T_WR] = {
206 		.type = UE_BULK,
207 		.endpoint = UE_ADDR_ANY,
208 		.direction = UE_DIR_OUT,
209 		.bufsize = UDBP_BUFFERSIZE,
210 		.flags = {.pipe_bof = 1,.force_short_xfer = 1,},
211 		.callback = &udbp_bulk_write_callback,
212 		.timeout = UDBP_TIMEOUT,
213 	},
214 
215 	[UDBP_T_RD] = {
216 		.type = UE_BULK,
217 		.endpoint = UE_ADDR_ANY,
218 		.direction = UE_DIR_IN,
219 		.bufsize = UDBP_BUFFERSIZE,
220 		.flags = {.pipe_bof = 1,.short_xfer_ok = 1,},
221 		.callback = &udbp_bulk_read_callback,
222 	},
223 
224 	[UDBP_T_WR_CS] = {
225 		.type = UE_CONTROL,
226 		.endpoint = 0x00,	/* Control pipe */
227 		.direction = UE_DIR_ANY,
228 		.bufsize = sizeof(struct usb_device_request),
229 		.callback = &udbp_bulk_write_clear_stall_callback,
230 		.timeout = 1000,	/* 1 second */
231 		.interval = 50,	/* 50ms */
232 	},
233 
234 	[UDBP_T_RD_CS] = {
235 		.type = UE_CONTROL,
236 		.endpoint = 0x00,	/* Control pipe */
237 		.direction = UE_DIR_ANY,
238 		.bufsize = sizeof(struct usb_device_request),
239 		.callback = &udbp_bulk_read_clear_stall_callback,
240 		.timeout = 1000,	/* 1 second */
241 		.interval = 50,	/* 50ms */
242 	},
243 };
244 
245 static devclass_t udbp_devclass;
246 
247 static device_method_t udbp_methods[] = {
248 	/* Device interface */
249 	DEVMETHOD(device_probe, udbp_probe),
250 	DEVMETHOD(device_attach, udbp_attach),
251 	DEVMETHOD(device_detach, udbp_detach),
252 	{0, 0}
253 };
254 
255 static driver_t udbp_driver = {
256 	.name = "udbp",
257 	.methods = udbp_methods,
258 	.size = sizeof(struct udbp_softc),
259 };
260 
261 DRIVER_MODULE(udbp, uhub, udbp_driver, udbp_devclass, udbp_modload, 0);
262 MODULE_DEPEND(udbp, netgraph, NG_ABI_VERSION, NG_ABI_VERSION, NG_ABI_VERSION);
263 MODULE_DEPEND(udbp, usb, 1, 1, 1);
264 MODULE_VERSION(udbp, 1);
265 
266 static int
267 udbp_modload(module_t mod, int event, void *data)
268 {
269 	int error;
270 
271 	switch (event) {
272 	case MOD_LOAD:
273 		error = ng_newtype(&ng_udbp_typestruct);
274 		if (error != 0) {
275 			printf("%s: Could not register "
276 			    "Netgraph node type, error=%d\n",
277 			    NG_UDBP_NODE_TYPE, error);
278 		}
279 		break;
280 
281 	case MOD_UNLOAD:
282 		error = ng_rmtype(&ng_udbp_typestruct);
283 		break;
284 
285 	default:
286 		error = EOPNOTSUPP;
287 		break;
288 	}
289 	return (error);
290 }
291 
292 static int
293 udbp_probe(device_t dev)
294 {
295 	struct usb_attach_arg *uaa = device_get_ivars(dev);
296 
297 	if (uaa->usb_mode != USB_MODE_HOST) {
298 		return (ENXIO);
299 	}
300 	/*
301 	 * XXX Julian, add the id of the device if you have one to test
302 	 * things with. run 'usbdevs -v' and note the 3 ID's that appear.
303 	 * The Vendor Id and Product Id are in hex and the Revision Id is in
304 	 * bcd. But as usual if the revision is 0x101 then you should
305 	 * compare the revision id in the device descriptor with 0x101 Or go
306 	 * search the file usbdevs.h. Maybe the device is already in there.
307 	 */
308 	if (((uaa->info.idVendor == USB_VENDOR_NETCHIP) &&
309 	    (uaa->info.idProduct == USB_PRODUCT_NETCHIP_TURBOCONNECT)))
310 		return (0);
311 
312 	if (((uaa->info.idVendor == USB_VENDOR_PROLIFIC) &&
313 	    ((uaa->info.idProduct == USB_PRODUCT_PROLIFIC_PL2301) ||
314 	    (uaa->info.idProduct == USB_PRODUCT_PROLIFIC_PL2302))))
315 		return (0);
316 
317 	if ((uaa->info.idVendor == USB_VENDOR_ANCHOR) &&
318 	    (uaa->info.idProduct == USB_PRODUCT_ANCHOR_EZLINK))
319 		return (0);
320 
321 	if ((uaa->info.idVendor == USB_VENDOR_GENESYS) &&
322 	    (uaa->info.idProduct == USB_PRODUCT_GENESYS_GL620USB))
323 		return (0);
324 
325 	return (ENXIO);
326 }
327 
328 static int
329 udbp_attach(device_t dev)
330 {
331 	struct usb_attach_arg *uaa = device_get_ivars(dev);
332 	struct udbp_softc *sc = device_get_softc(dev);
333 	int error;
334 
335 	device_set_usb_desc(dev);
336 
337 	snprintf(sc->sc_name, sizeof(sc->sc_name),
338 	    "%s", device_get_nameunit(dev));
339 
340 	mtx_init(&sc->sc_mtx, "udbp lock", NULL, MTX_DEF | MTX_RECURSE);
341 
342 	error = usbd_transfer_setup(uaa->device, &uaa->info.bIfaceIndex,
343 	    sc->sc_xfer, udbp_config, UDBP_T_MAX, sc, &sc->sc_mtx);
344 	if (error) {
345 		DPRINTF("error=%s\n", usbd_errstr(error));
346 		goto detach;
347 	}
348 	NG_BT_MBUFQ_INIT(&sc->sc_xmitq, UDBP_Q_MAXLEN);
349 
350 	NG_BT_MBUFQ_INIT(&sc->sc_xmitq_hipri, UDBP_Q_MAXLEN);
351 
352 	/* create Netgraph node */
353 
354 	if (ng_make_node_common(&ng_udbp_typestruct, &sc->sc_node) != 0) {
355 		printf("%s: Could not create Netgraph node\n",
356 		    sc->sc_name);
357 		sc->sc_node = NULL;
358 		goto detach;
359 	}
360 	/* name node */
361 
362 	if (ng_name_node(sc->sc_node, sc->sc_name) != 0) {
363 		printf("%s: Could not name node\n",
364 		    sc->sc_name);
365 		NG_NODE_UNREF(sc->sc_node);
366 		sc->sc_node = NULL;
367 		goto detach;
368 	}
369 	NG_NODE_SET_PRIVATE(sc->sc_node, sc);
370 
371 	/* the device is now operational */
372 
373 	return (0);			/* success */
374 
375 detach:
376 	udbp_detach(dev);
377 	return (ENOMEM);		/* failure */
378 }
379 
380 static int
381 udbp_detach(device_t dev)
382 {
383 	struct udbp_softc *sc = device_get_softc(dev);
384 
385 	/* destroy Netgraph node */
386 
387 	if (sc->sc_node != NULL) {
388 		NG_NODE_SET_PRIVATE(sc->sc_node, NULL);
389 		ng_rmnode_self(sc->sc_node);
390 		sc->sc_node = NULL;
391 	}
392 	/* free USB transfers, if any */
393 
394 	usbd_transfer_unsetup(sc->sc_xfer, UDBP_T_MAX);
395 
396 	mtx_destroy(&sc->sc_mtx);
397 
398 	/* destroy queues */
399 
400 	NG_BT_MBUFQ_DESTROY(&sc->sc_xmitq);
401 	NG_BT_MBUFQ_DESTROY(&sc->sc_xmitq_hipri);
402 
403 	/* extra check */
404 
405 	if (sc->sc_bulk_in_buffer) {
406 		m_freem(sc->sc_bulk_in_buffer);
407 		sc->sc_bulk_in_buffer = NULL;
408 	}
409 	return (0);			/* success */
410 }
411 
412 static void
413 udbp_bulk_read_callback(struct usb_xfer *xfer, usb_error_t error)
414 {
415 	struct udbp_softc *sc = usbd_xfer_softc(xfer);
416 	struct usb_page_cache *pc;
417 	struct mbuf *m;
418 	int actlen;
419 
420 	usbd_xfer_status(xfer, &actlen, NULL, NULL, NULL);
421 
422 	switch (USB_GET_STATE(xfer)) {
423 	case USB_ST_TRANSFERRED:
424 
425 		/* allocate new mbuf */
426 
427 		MGETHDR(m, M_DONTWAIT, MT_DATA);
428 
429 		if (m == NULL) {
430 			goto tr_setup;
431 		}
432 		MCLGET(m, M_DONTWAIT);
433 
434 		if (!(m->m_flags & M_EXT)) {
435 			m_freem(m);
436 			goto tr_setup;
437 		}
438 		m->m_pkthdr.len = m->m_len = actlen;
439 
440 		pc = usbd_xfer_get_frame(xfer, 0);
441 		usbd_copy_out(pc, 0, m->m_data, actlen);
442 
443 		sc->sc_bulk_in_buffer = m;
444 
445 		DPRINTF("received package %d bytes\n", actlen);
446 
447 	case USB_ST_SETUP:
448 tr_setup:
449 		if (sc->sc_bulk_in_buffer) {
450 			ng_send_fn(sc->sc_node, NULL, &udbp_bulk_read_complete, NULL, 0);
451 			return;
452 		}
453 		if (sc->sc_flags & UDBP_FLAG_READ_STALL) {
454 			usbd_transfer_start(sc->sc_xfer[UDBP_T_RD_CS]);
455 			return;
456 		}
457 		usbd_xfer_set_frame_len(xfer, 0, usbd_xfer_max_len(xfer));
458 		usbd_transfer_submit(xfer);
459 		return;
460 
461 	default:			/* Error */
462 		if (error != USB_ERR_CANCELLED) {
463 			/* try to clear stall first */
464 			sc->sc_flags |= UDBP_FLAG_READ_STALL;
465 			usbd_transfer_start(sc->sc_xfer[UDBP_T_RD_CS]);
466 		}
467 		return;
468 
469 	}
470 }
471 
472 static void
473 udbp_bulk_read_clear_stall_callback(struct usb_xfer *xfer, usb_error_t error)
474 {
475 	struct udbp_softc *sc = usbd_xfer_softc(xfer);
476 	struct usb_xfer *xfer_other = sc->sc_xfer[UDBP_T_RD];
477 
478 	if (usbd_clear_stall_callback(xfer, xfer_other)) {
479 		DPRINTF("stall cleared\n");
480 		sc->sc_flags &= ~UDBP_FLAG_READ_STALL;
481 		usbd_transfer_start(xfer_other);
482 	}
483 }
484 
485 static void
486 udbp_bulk_read_complete(node_p node, hook_p hook, void *arg1, int arg2)
487 {
488 	struct udbp_softc *sc = NG_NODE_PRIVATE(node);
489 	struct mbuf *m;
490 	int error;
491 
492 	if (sc == NULL) {
493 		return;
494 	}
495 	mtx_lock(&sc->sc_mtx);
496 
497 	m = sc->sc_bulk_in_buffer;
498 
499 	if (m) {
500 
501 		sc->sc_bulk_in_buffer = NULL;
502 
503 		if ((sc->sc_hook == NULL) ||
504 		    NG_HOOK_NOT_VALID(sc->sc_hook)) {
505 			DPRINTF("No upstream hook\n");
506 			goto done;
507 		}
508 		sc->sc_packets_in++;
509 
510 		NG_SEND_DATA_ONLY(error, sc->sc_hook, m);
511 
512 		m = NULL;
513 	}
514 done:
515 	if (m) {
516 		m_freem(m);
517 	}
518 	/* start USB bulk-in transfer, if not already started */
519 
520 	usbd_transfer_start(sc->sc_xfer[UDBP_T_RD]);
521 
522 	mtx_unlock(&sc->sc_mtx);
523 }
524 
525 static void
526 udbp_bulk_write_callback(struct usb_xfer *xfer, usb_error_t error)
527 {
528 	struct udbp_softc *sc = usbd_xfer_softc(xfer);
529 	struct usb_page_cache *pc;
530 	struct mbuf *m;
531 
532 	switch (USB_GET_STATE(xfer)) {
533 	case USB_ST_TRANSFERRED:
534 
535 		sc->sc_packets_out++;
536 
537 	case USB_ST_SETUP:
538 		if (sc->sc_flags & UDBP_FLAG_WRITE_STALL) {
539 			usbd_transfer_start(sc->sc_xfer[UDBP_T_WR_CS]);
540 			return;
541 		}
542 		/* get next mbuf, if any */
543 
544 		NG_BT_MBUFQ_DEQUEUE(&sc->sc_xmitq_hipri, m);
545 		if (m == NULL) {
546 			NG_BT_MBUFQ_DEQUEUE(&sc->sc_xmitq, m);
547 			if (m == NULL) {
548 				DPRINTF("Data queue is empty\n");
549 				return;
550 			}
551 		}
552 		if (m->m_pkthdr.len > MCLBYTES) {
553 			DPRINTF("truncating large packet "
554 			    "from %d to %d bytes\n", m->m_pkthdr.len,
555 			    MCLBYTES);
556 			m->m_pkthdr.len = MCLBYTES;
557 		}
558 		pc = usbd_xfer_get_frame(xfer, 0);
559 		usbd_m_copy_in(pc, 0, m, 0, m->m_pkthdr.len);
560 
561 		usbd_xfer_set_frame_len(xfer, 0, m->m_pkthdr.len);
562 
563 		DPRINTF("packet out: %d bytes\n", m->m_pkthdr.len);
564 
565 		m_freem(m);
566 
567 		usbd_transfer_submit(xfer);
568 		return;
569 
570 	default:			/* Error */
571 		if (error != USB_ERR_CANCELLED) {
572 			/* try to clear stall first */
573 			sc->sc_flags |= UDBP_FLAG_WRITE_STALL;
574 			usbd_transfer_start(sc->sc_xfer[UDBP_T_WR_CS]);
575 		}
576 		return;
577 
578 	}
579 }
580 
581 static void
582 udbp_bulk_write_clear_stall_callback(struct usb_xfer *xfer, usb_error_t error)
583 {
584 	struct udbp_softc *sc = usbd_xfer_softc(xfer);
585 	struct usb_xfer *xfer_other = sc->sc_xfer[UDBP_T_WR];
586 
587 	if (usbd_clear_stall_callback(xfer, xfer_other)) {
588 		DPRINTF("stall cleared\n");
589 		sc->sc_flags &= ~UDBP_FLAG_WRITE_STALL;
590 		usbd_transfer_start(xfer_other);
591 	}
592 }
593 
594 /***********************************************************************
595  * Start of Netgraph methods
596  **********************************************************************/
597 
598 /*
599  * If this is a device node so this work is done in the attach()
600  * routine and the constructor will return EINVAL as you should not be able
601  * to create nodes that depend on hardware (unless you can add the hardware :)
602  */
603 static int
604 ng_udbp_constructor(node_p node)
605 {
606 	return (EINVAL);
607 }
608 
609 /*
610  * Give our ok for a hook to be added...
611  * If we are not running this might kick a device into life.
612  * Possibly decode information out of the hook name.
613  * Add the hook's private info to the hook structure.
614  * (if we had some). In this example, we assume that there is a
615  * an array of structs, called 'channel' in the private info,
616  * one for each active channel. The private
617  * pointer of each hook points to the appropriate UDBP_hookinfo struct
618  * so that the source of an input packet is easily identified.
619  */
620 static int
621 ng_udbp_newhook(node_p node, hook_p hook, const char *name)
622 {
623 	struct udbp_softc *sc = NG_NODE_PRIVATE(node);
624 	int32_t error = 0;
625 
626 	if (strcmp(name, NG_UDBP_HOOK_NAME)) {
627 		return (EINVAL);
628 	}
629 	mtx_lock(&sc->sc_mtx);
630 
631 	if (sc->sc_hook != NULL) {
632 		error = EISCONN;
633 	} else {
634 		sc->sc_hook = hook;
635 		NG_HOOK_SET_PRIVATE(hook, NULL);
636 	}
637 
638 	mtx_unlock(&sc->sc_mtx);
639 
640 	return (error);
641 }
642 
643 /*
644  * Get a netgraph control message.
645  * Check it is one we understand. If needed, send a response.
646  * We could save the address for an async action later, but don't here.
647  * Always free the message.
648  * The response should be in a malloc'd region that the caller can 'free'.
649  * A response is not required.
650  * Theoretically you could respond defferently to old message types if
651  * the cookie in the header didn't match what we consider to be current
652  * (so that old userland programs could continue to work).
653  */
654 static int
655 ng_udbp_rcvmsg(node_p node, item_p item, hook_p lasthook)
656 {
657 	struct udbp_softc *sc = NG_NODE_PRIVATE(node);
658 	struct ng_mesg *resp = NULL;
659 	int error = 0;
660 	struct ng_mesg *msg;
661 
662 	NGI_GET_MSG(item, msg);
663 	/* Deal with message according to cookie and command */
664 	switch (msg->header.typecookie) {
665 	case NGM_UDBP_COOKIE:
666 		switch (msg->header.cmd) {
667 		case NGM_UDBP_GET_STATUS:
668 			{
669 				struct ngudbpstat *stats;
670 
671 				NG_MKRESPONSE(resp, msg, sizeof(*stats), M_NOWAIT);
672 				if (!resp) {
673 					error = ENOMEM;
674 					break;
675 				}
676 				stats = (struct ngudbpstat *)resp->data;
677 				mtx_lock(&sc->sc_mtx);
678 				stats->packets_in = sc->sc_packets_in;
679 				stats->packets_out = sc->sc_packets_out;
680 				mtx_unlock(&sc->sc_mtx);
681 				break;
682 			}
683 		case NGM_UDBP_SET_FLAG:
684 			if (msg->header.arglen != sizeof(uint32_t)) {
685 				error = EINVAL;
686 				break;
687 			}
688 			DPRINTF("flags = 0x%08x\n",
689 			    *((uint32_t *)msg->data));
690 			break;
691 		default:
692 			error = EINVAL;	/* unknown command */
693 			break;
694 		}
695 		break;
696 	default:
697 		error = EINVAL;		/* unknown cookie type */
698 		break;
699 	}
700 
701 	/* Take care of synchronous response, if any */
702 	NG_RESPOND_MSG(error, node, item, resp);
703 	NG_FREE_MSG(msg);
704 	return (error);
705 }
706 
707 /*
708  * Accept data from the hook and queue it for output.
709  */
710 static int
711 ng_udbp_rcvdata(hook_p hook, item_p item)
712 {
713 	struct udbp_softc *sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
714 	struct ng_bt_mbufq *queue_ptr;
715 	struct mbuf *m;
716 	struct ng_tag_prio *ptag;
717 	int error;
718 
719 	if (sc == NULL) {
720 		NG_FREE_ITEM(item);
721 		return (EHOSTDOWN);
722 	}
723 	NGI_GET_M(item, m);
724 	NG_FREE_ITEM(item);
725 
726 	/*
727 	 * Now queue the data for when it can be sent
728 	 */
729 	ptag = (void *)m_tag_locate(m, NGM_GENERIC_COOKIE,
730 	    NG_TAG_PRIO, NULL);
731 
732 	if (ptag && (ptag->priority > NG_PRIO_CUTOFF))
733 		queue_ptr = &sc->sc_xmitq_hipri;
734 	else
735 		queue_ptr = &sc->sc_xmitq;
736 
737 	mtx_lock(&sc->sc_mtx);
738 
739 	if (NG_BT_MBUFQ_FULL(queue_ptr)) {
740 		NG_BT_MBUFQ_DROP(queue_ptr);
741 		NG_FREE_M(m);
742 		error = ENOBUFS;
743 	} else {
744 		NG_BT_MBUFQ_ENQUEUE(queue_ptr, m);
745 		/*
746 		 * start bulk-out transfer, if not already started:
747 		 */
748 		usbd_transfer_start(sc->sc_xfer[UDBP_T_WR]);
749 		error = 0;
750 	}
751 
752 	mtx_unlock(&sc->sc_mtx);
753 
754 	return (error);
755 }
756 
757 /*
758  * Do local shutdown processing..
759  * We are a persistant device, we refuse to go away, and
760  * only remove our links and reset ourself.
761  */
762 static int
763 ng_udbp_rmnode(node_p node)
764 {
765 	struct udbp_softc *sc = NG_NODE_PRIVATE(node);
766 
767 	/* Let old node go */
768 	NG_NODE_SET_PRIVATE(node, NULL);
769 	NG_NODE_UNREF(node);		/* forget it ever existed */
770 
771 	if (sc == NULL) {
772 		goto done;
773 	}
774 	/* Create Netgraph node */
775 	if (ng_make_node_common(&ng_udbp_typestruct, &sc->sc_node) != 0) {
776 		printf("%s: Could not create Netgraph node\n",
777 		    sc->sc_name);
778 		sc->sc_node = NULL;
779 		goto done;
780 	}
781 	/* Name node */
782 	if (ng_name_node(sc->sc_node, sc->sc_name) != 0) {
783 		printf("%s: Could not name Netgraph node\n",
784 		    sc->sc_name);
785 		NG_NODE_UNREF(sc->sc_node);
786 		sc->sc_node = NULL;
787 		goto done;
788 	}
789 	NG_NODE_SET_PRIVATE(sc->sc_node, sc);
790 
791 done:
792 	if (sc) {
793 		mtx_unlock(&sc->sc_mtx);
794 	}
795 	return (0);
796 }
797 
798 /*
799  * This is called once we've already connected a new hook to the other node.
800  * It gives us a chance to balk at the last minute.
801  */
802 static int
803 ng_udbp_connect(hook_p hook)
804 {
805 	struct udbp_softc *sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
806 
807 	/* probably not at splnet, force outward queueing */
808 	NG_HOOK_FORCE_QUEUE(NG_HOOK_PEER(hook));
809 
810 	mtx_lock(&sc->sc_mtx);
811 
812 	sc->sc_flags |= (UDBP_FLAG_READ_STALL |
813 	    UDBP_FLAG_WRITE_STALL);
814 
815 	/* start bulk-in transfer */
816 	usbd_transfer_start(sc->sc_xfer[UDBP_T_RD]);
817 
818 	/* start bulk-out transfer */
819 	usbd_transfer_start(sc->sc_xfer[UDBP_T_WR]);
820 
821 	mtx_unlock(&sc->sc_mtx);
822 
823 	return (0);
824 }
825 
826 /*
827  * Dook disconnection
828  *
829  * For this type, removal of the last link destroys the node
830  */
831 static int
832 ng_udbp_disconnect(hook_p hook)
833 {
834 	struct udbp_softc *sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
835 	int error = 0;
836 
837 	if (sc != NULL) {
838 
839 		mtx_lock(&sc->sc_mtx);
840 
841 		if (hook != sc->sc_hook) {
842 			error = EINVAL;
843 		} else {
844 
845 			/* stop bulk-in transfer */
846 			usbd_transfer_stop(sc->sc_xfer[UDBP_T_RD_CS]);
847 			usbd_transfer_stop(sc->sc_xfer[UDBP_T_RD]);
848 
849 			/* stop bulk-out transfer */
850 			usbd_transfer_stop(sc->sc_xfer[UDBP_T_WR_CS]);
851 			usbd_transfer_stop(sc->sc_xfer[UDBP_T_WR]);
852 
853 			/* cleanup queues */
854 			NG_BT_MBUFQ_DRAIN(&sc->sc_xmitq);
855 			NG_BT_MBUFQ_DRAIN(&sc->sc_xmitq_hipri);
856 
857 			if (sc->sc_bulk_in_buffer) {
858 				m_freem(sc->sc_bulk_in_buffer);
859 				sc->sc_bulk_in_buffer = NULL;
860 			}
861 			sc->sc_hook = NULL;
862 		}
863 
864 		mtx_unlock(&sc->sc_mtx);
865 	}
866 	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
867 	    && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
868 		ng_rmnode_self(NG_HOOK_NODE(hook));
869 
870 	return (error);
871 }
872