xref: /freebsd/sys/dev/usb/net/if_cdceem.c (revision b622dc25cf3c9940df3e4f7ac9fc961093db6ea8)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (C) 2012 Ben Gray <bgray@freebsd.org>.
5  * Copyright (C) 2018 The FreeBSD Foundation.
6  * Copyright (c) 2019 Edward Tomasz Napierala <trasz@FreeBSD.org>
7  *
8  * This software was developed by Arshan Khanifar <arshankhanifar@gmail.com>
9  * under sponsorship from the FreeBSD Foundation.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 /*
34  * Universal Serial Bus Communications Class Subclass Specification
35  * for Ethernet Emulation Model Devices:
36  *
37  * https://usb.org/sites/default/files/CDC_EEM10.pdf
38  */
39 
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include <sys/gsb_crc32.h>
44 #include <sys/eventhandler.h>
45 #include <sys/stdint.h>
46 #include <sys/stddef.h>
47 #include <sys/queue.h>
48 #include <sys/systm.h>
49 #include <sys/socket.h>
50 #include <sys/kernel.h>
51 #include <sys/bus.h>
52 #include <sys/module.h>
53 #include <sys/lock.h>
54 #include <sys/mutex.h>
55 #include <sys/condvar.h>
56 #include <sys/sysctl.h>
57 #include <sys/sx.h>
58 #include <sys/unistd.h>
59 #include <sys/callout.h>
60 #include <sys/malloc.h>
61 #include <sys/priv.h>
62 
63 #include <net/if.h>
64 #include <net/if_var.h>
65 
66 #include <dev/usb/usb.h>
67 #include <dev/usb/usbdi.h>
68 #include <dev/usb/usbdi_util.h>
69 #include <dev/usb/usb_cdc.h>
70 #include "usbdevs.h"
71 
72 #define	USB_DEBUG_VAR cdceem_debug
73 #include <dev/usb/usb_debug.h>
74 #include <dev/usb/usb_process.h>
75 #include <dev/usb/usb_msctest.h>
76 #include "usb_if.h"
77 
78 #include <dev/usb/net/usb_ethernet.h>
79 
80 #define	CDCEEM_FRAMES_MAX	1
81 #define	CDCEEM_ECHO_MAX		1024
82 
83 #define	CDCEEM_ECHO_PAYLOAD	\
84     "ICH DALEKOPIS FALSZUJE GDY PROBY XQV NIE WYTRZYMUJE 1234567890"
85 
86 enum {
87 	CDCEEM_BULK_RX,
88 	CDCEEM_BULK_TX,
89 	CDCEEM_N_TRANSFER,
90 };
91 
92 struct cdceem_softc {
93 	struct usb_ether	sc_ue;
94 	struct mtx		sc_mtx;
95 	int			sc_flags;
96 	struct usb_xfer		*sc_xfer[CDCEEM_N_TRANSFER];
97 	size_t			sc_echo_len;
98 	char			sc_echo_buffer[CDCEEM_ECHO_MAX];
99 };
100 
101 #define	CDCEEM_SC_FLAGS_ECHO_RESPONSE_PENDING	0x1
102 #define	CDCEEM_SC_FLAGS_ECHO_PENDING		0x2
103 
104 static SYSCTL_NODE(_hw_usb, OID_AUTO, cdceem, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
105     "USB CDC EEM");
106 static int cdceem_debug = 1;
107 SYSCTL_INT(_hw_usb_cdceem, OID_AUTO, debug, CTLFLAG_RWTUN,
108     &cdceem_debug, 0, "Debug level");
109 static int cdceem_send_echoes = 0;
110 SYSCTL_INT(_hw_usb_cdceem, OID_AUTO, send_echoes, CTLFLAG_RWTUN,
111     &cdceem_send_echoes, 0, "Send an Echo command");
112 static int cdceem_send_fake_crc = 0;
113 SYSCTL_INT(_hw_usb_cdceem, OID_AUTO, send_fake_crc, CTLFLAG_RWTUN,
114     &cdceem_send_fake_crc, 0, "Use 0xdeadbeef instead of CRC");
115 
116 #define	CDCEEM_DEBUG(S, X, ...)						\
117 	do {								\
118 		if (cdceem_debug > 1) {					\
119 			device_printf(S->sc_ue.ue_dev, "%s: " X "\n",	\
120 			    __func__, ## __VA_ARGS__);			\
121 		}							\
122 	} while (0)
123 
124 #define	CDCEEM_WARN(S, X, ...)						\
125 	do {								\
126 		if (cdceem_debug > 0) {					\
127 			device_printf(S->sc_ue.ue_dev,			\
128 			    "WARNING: %s: " X "\n",			\
129 			    __func__, ## __VA_ARGS__);			\
130 		}							\
131 	} while (0)
132 
133 #define	CDCEEM_LOCK(X)				mtx_lock(&(X)->sc_mtx)
134 #define	CDCEEM_UNLOCK(X)			mtx_unlock(&(X)->sc_mtx)
135 
136 #define	CDCEEM_TYPE_CMD				(0x1 << 15)
137 
138 #define	CDCEEM_CMD_MASK				(0x7 << 11)
139 
140 #define	CDCEEM_CMD_ECHO				(0x0 << 11)
141 #define	CDCEEM_CMD_ECHO_RESPONSE		(0x1 << 11)
142 #define	CDCEEM_CMD_SUSPEND_HINT			(0x2 << 11)
143 #define	CDCEEM_CMD_RESPONSE_HINT		(0x3 << 11)
144 #define	CDCEEM_CMD_RESPONSE_COMPLETE_HINT	(0x4 << 11)
145 #define	CDCEEM_CMD_TICKLE			(0x5 << 11)
146 
147 #define	CDCEEM_CMD_RESERVED			(0x1 << 14)
148 
149 #define	CDCEEM_ECHO_LEN_MASK			0x3ff
150 
151 #define	CDCEEM_DATA_CRC				(0x1 << 14)
152 #define	CDCEEM_DATA_LEN_MASK			0x3fff
153 
154 static device_probe_t cdceem_probe;
155 static device_attach_t cdceem_attach;
156 static device_detach_t cdceem_detach;
157 static device_suspend_t cdceem_suspend;
158 static device_resume_t cdceem_resume;
159 
160 static usb_callback_t cdceem_bulk_write_callback;
161 static usb_callback_t cdceem_bulk_read_callback;
162 
163 static uether_fn_t cdceem_attach_post;
164 static uether_fn_t cdceem_init;
165 static uether_fn_t cdceem_stop;
166 static uether_fn_t cdceem_start;
167 static uether_fn_t cdceem_setmulti;
168 static uether_fn_t cdceem_setpromisc;
169 
170 static uint32_t	cdceem_m_crc32(struct mbuf *, uint32_t, uint32_t);
171 
172 static const struct usb_config cdceem_config[CDCEEM_N_TRANSFER] = {
173 	[CDCEEM_BULK_TX] = {
174 		.type = UE_BULK,
175 		.endpoint = UE_ADDR_ANY,
176 		.direction = UE_DIR_TX,
177 		.bufsize = 16 * (MCLBYTES + 16),
178 		.flags = {.pipe_bof = 1,.force_short_xfer = 1,},
179 		.callback = cdceem_bulk_write_callback,
180 		.timeout = 10000,	/* 10 seconds */
181 		.usb_mode = USB_MODE_DUAL,
182 	},
183 
184 	[CDCEEM_BULK_RX] = {
185 		.type = UE_BULK,
186 		.endpoint = UE_ADDR_ANY,
187 		.direction = UE_DIR_RX,
188 		.bufsize = 20480,	/* bytes */
189 		.flags = {.pipe_bof = 1,.short_xfer_ok = 1,},
190 		.callback = cdceem_bulk_read_callback,
191 		.timeout = 0,	/* no timeout */
192 		.usb_mode = USB_MODE_DUAL,
193 	},
194 };
195 
196 static device_method_t cdceem_methods[] = {
197 	/* Device interface */
198 	DEVMETHOD(device_probe, cdceem_probe),
199 	DEVMETHOD(device_attach, cdceem_attach),
200 	DEVMETHOD(device_detach, cdceem_detach),
201 	DEVMETHOD(device_suspend, cdceem_suspend),
202 	DEVMETHOD(device_resume, cdceem_resume),
203 
204 	DEVMETHOD_END
205 };
206 
207 static driver_t cdceem_driver = {
208 	.name = "cdceem",
209 	.methods = cdceem_methods,
210 	.size = sizeof(struct cdceem_softc),
211 };
212 
213 static devclass_t cdceem_devclass;
214 
215 static const STRUCT_USB_DUAL_ID cdceem_dual_devs[] = {
216 	{USB_IFACE_CLASS(UICLASS_CDC),
217 		USB_IFACE_SUBCLASS(UISUBCLASS_ETHERNET_EMULATION_MODEL),
218 		0},
219 };
220 
221 DRIVER_MODULE(cdceem, uhub, cdceem_driver, cdceem_devclass, NULL, NULL);
222 MODULE_VERSION(cdceem, 1);
223 MODULE_DEPEND(cdceem, uether, 1, 1, 1);
224 MODULE_DEPEND(cdceem, usb, 1, 1, 1);
225 MODULE_DEPEND(cdceem, ether, 1, 1, 1);
226 USB_PNP_DUAL_INFO(cdceem_dual_devs);
227 
228 static const struct usb_ether_methods cdceem_ue_methods = {
229 	.ue_attach_post = cdceem_attach_post,
230 	.ue_start = cdceem_start,
231 	.ue_init = cdceem_init,
232 	.ue_stop = cdceem_stop,
233 	.ue_setmulti = cdceem_setmulti,
234 	.ue_setpromisc = cdceem_setpromisc,
235 };
236 
237 static int
238 cdceem_probe(device_t dev)
239 {
240 	struct usb_attach_arg *uaa;
241 	int error;
242 
243 	uaa = device_get_ivars(dev);
244 	error = usbd_lookup_id_by_uaa(cdceem_dual_devs,
245 	    sizeof(cdceem_dual_devs), uaa);
246 
247 	return (error);
248 }
249 
250 static void
251 cdceem_attach_post(struct usb_ether *ue)
252 {
253 
254 	return;
255 }
256 
257 static int
258 cdceem_attach(device_t dev)
259 {
260 	struct cdceem_softc *sc;
261 	struct usb_ether *ue;
262 	struct usb_attach_arg *uaa;
263 	int error;
264 	uint8_t iface_index;
265 
266 	sc = device_get_softc(dev);
267 	ue = &sc->sc_ue;
268 	uaa = device_get_ivars(dev);
269 
270 	device_set_usb_desc(dev);
271 
272 	mtx_init(&sc->sc_mtx, device_get_nameunit(dev), NULL, MTX_DEF);
273 
274 	/* Setup the endpoints. */
275 	iface_index = 0;
276 	error = usbd_transfer_setup(uaa->device, &iface_index, sc->sc_xfer,
277 	    cdceem_config, CDCEEM_N_TRANSFER, sc, &sc->sc_mtx);
278 	if (error != 0) {
279 		CDCEEM_WARN(sc,
280 		    "allocating USB transfers failed, error %d", error);
281 		mtx_destroy(&sc->sc_mtx);
282 		return (error);
283 	}
284 
285 	/* Random MAC address. */
286 	arc4rand(ue->ue_eaddr, ETHER_ADDR_LEN, 0);
287 	ue->ue_eaddr[0] &= ~0x01;	/* unicast */
288 	ue->ue_eaddr[0] |= 0x02;	/* locally administered */
289 
290 	ue->ue_sc = sc;
291 	ue->ue_dev = dev;
292 	ue->ue_udev = uaa->device;
293 	ue->ue_mtx = &sc->sc_mtx;
294 	ue->ue_methods = &cdceem_ue_methods;
295 
296 	error = uether_ifattach(ue);
297 	if (error != 0) {
298 		CDCEEM_WARN(sc, "could not attach interface, error %d", error);
299 		usbd_transfer_unsetup(sc->sc_xfer, CDCEEM_N_TRANSFER);
300 		mtx_destroy(&sc->sc_mtx);
301 		return (error);
302 	}
303 
304 	return (0);
305 }
306 
307 static int
308 cdceem_detach(device_t dev)
309 {
310 	struct cdceem_softc *sc = device_get_softc(dev);
311 	struct usb_ether *ue = &sc->sc_ue;
312 
313 	/* Stop all USB transfers first. */
314 	usbd_transfer_unsetup(sc->sc_xfer, CDCEEM_N_TRANSFER);
315 	uether_ifdetach(ue);
316 	mtx_destroy(&sc->sc_mtx);
317 
318 	return (0);
319 }
320 
321 static void
322 cdceem_handle_cmd(struct usb_xfer *xfer, uint16_t hdr, int *offp)
323 {
324 	struct cdceem_softc *sc;
325 	struct usb_page_cache *pc;
326 	int actlen, off;
327 	uint16_t pktlen;
328 
329 	off = *offp;
330 	sc = usbd_xfer_softc(xfer);
331 	pc = usbd_xfer_get_frame(xfer, 0);
332 	usbd_xfer_status(xfer, &actlen, NULL, NULL, NULL);
333 
334 	if (hdr & CDCEEM_CMD_RESERVED) {
335 		CDCEEM_WARN(sc, "received command header %#x "
336 		    "with Reserved bit set; ignoring", hdr);
337 		return;
338 	}
339 
340 	switch (hdr & CDCEEM_CMD_MASK) {
341 	case CDCEEM_CMD_ECHO:
342 		pktlen = hdr & CDCEEM_ECHO_LEN_MASK;
343 		CDCEEM_DEBUG(sc, "received Echo, length %d", pktlen);
344 
345 		if (pktlen > (actlen - off)) {
346 			CDCEEM_WARN(sc,
347 			    "bad Echo length %d, should be at most %d",
348 			    pktlen, actlen - off);
349 			break;
350 		}
351 
352 		if (pktlen > sizeof(sc->sc_echo_buffer)) {
353 			CDCEEM_WARN(sc,
354 			    "Echo length %u too big, must be less than %zd",
355 			    pktlen, sizeof(sc->sc_echo_buffer));
356 			break;
357 		}
358 
359 		sc->sc_flags |= CDCEEM_SC_FLAGS_ECHO_RESPONSE_PENDING;
360 		sc->sc_echo_len = pktlen;
361 		usbd_copy_out(pc, off, sc->sc_echo_buffer, pktlen);
362 		off += pktlen;
363 		break;
364 
365 	case CDCEEM_CMD_ECHO_RESPONSE:
366 		pktlen = hdr & CDCEEM_ECHO_LEN_MASK;
367 		CDCEEM_DEBUG(sc, "received Echo Response, length %d", pktlen);
368 
369 		if (pktlen > (actlen - off)) {
370 			CDCEEM_WARN(sc,
371 			    "bad Echo Response length %d, "
372 			    "should be at most %d",
373 			    pktlen, actlen - off);
374 			break;
375 		}
376 
377 		if (pktlen != sizeof(CDCEEM_ECHO_PAYLOAD)) {
378 			CDCEEM_WARN(sc, "received Echo Response with bad "
379 			    "length %hu, should be %zd",
380 			    pktlen, sizeof(CDCEEM_ECHO_PAYLOAD));
381 			break;
382 		}
383 
384 		usbd_copy_out(pc, off, sc->sc_echo_buffer, pktlen);
385 		off += pktlen;
386 
387 		if (memcmp(sc->sc_echo_buffer, CDCEEM_ECHO_PAYLOAD,
388 		    sizeof(CDCEEM_ECHO_PAYLOAD)) != 0) {
389 			CDCEEM_WARN(sc,
390 			    "received Echo Response payload does not match");
391 		} else {
392 			CDCEEM_DEBUG(sc, "received Echo Response is valid");
393 		}
394 		break;
395 
396 	case CDCEEM_CMD_SUSPEND_HINT:
397 		CDCEEM_DEBUG(sc, "received SuspendHint; ignoring");
398 		break;
399 
400 	case CDCEEM_CMD_RESPONSE_HINT:
401 		CDCEEM_DEBUG(sc, "received ResponseHint; ignoring");
402 		break;
403 
404 	case CDCEEM_CMD_RESPONSE_COMPLETE_HINT:
405 		CDCEEM_DEBUG(sc, "received ResponseCompleteHint; ignoring");
406 		break;
407 
408 	case CDCEEM_CMD_TICKLE:
409 		CDCEEM_DEBUG(sc, "received Tickle; ignoring");
410 		break;
411 
412 	default:
413 		CDCEEM_WARN(sc,
414 		    "received unknown command %u, header %#x; ignoring",
415 		    (hdr & CDCEEM_CMD_MASK >> 11), hdr);
416 		break;
417 	}
418 
419 	*offp = off;
420 }
421 
422 static void
423 cdceem_handle_data(struct usb_xfer *xfer, uint16_t hdr, int *offp)
424 {
425 	struct cdceem_softc *sc;
426 	struct usb_page_cache *pc;
427 	struct usb_ether *ue;
428 	struct ifnet *ifp;
429 	struct mbuf *m;
430 	uint32_t computed_crc, received_crc;
431 	int pktlen;
432 	int actlen;
433 	int off;
434 
435 	off = *offp;
436 	sc = usbd_xfer_softc(xfer);
437 	pc = usbd_xfer_get_frame(xfer, 0);
438 	ue = &sc->sc_ue;
439 	ifp = uether_getifp(ue);
440 	usbd_xfer_status(xfer, &actlen, NULL, NULL, NULL);
441 
442 	pktlen = hdr & CDCEEM_DATA_LEN_MASK;
443 	CDCEEM_DEBUG(sc, "received Data, CRC %s, length %d",
444 	    (hdr & CDCEEM_DATA_CRC) ? "valid" : "absent",
445 	    pktlen);
446 
447 	if (pktlen < (ETHER_HDR_LEN + 4)) {
448 		CDCEEM_WARN(sc,
449 		    "bad ethernet frame length %d, should be at least %d",
450 		    pktlen, ETHER_HDR_LEN);
451 		if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
452 		return;
453 	}
454 
455 	if (pktlen > (actlen - off)) {
456 		CDCEEM_WARN(sc,
457 		    "bad ethernet frame length %d, should be at most %d",
458 		    pktlen, actlen - off);
459 		if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
460 		return;
461 	}
462 
463 	m = uether_newbuf();
464 	if (m == NULL) {
465 		CDCEEM_WARN(sc, "uether_newbuf() failed");
466 		if_inc_counter(ifp, IFCOUNTER_IQDROPS, 1);
467 		return;
468 	}
469 
470 	pktlen -= 4; /* Subtract the CRC. */
471 
472 	if (pktlen > m->m_len) {
473 		CDCEEM_WARN(sc, "buffer too small %d vs %d bytes",
474 		    pktlen, m->m_len);
475 		if_inc_counter(ifp, IFCOUNTER_IQDROPS, 1);
476 		m_freem(m);
477 		return;
478 	}
479 	usbd_copy_out(pc, off, mtod(m, uint8_t *), pktlen);
480 	off += pktlen;
481 
482 	usbd_copy_out(pc, off, &received_crc, sizeof(received_crc));
483 	off += sizeof(received_crc);
484 
485 	if (hdr & CDCEEM_DATA_CRC) {
486 		computed_crc = cdceem_m_crc32(m, 0, pktlen);
487 	} else {
488 		computed_crc = be32toh(0xdeadbeef);
489 	}
490 
491 	if (received_crc != computed_crc) {
492 		CDCEEM_WARN(sc,
493 		    "received Data packet with wrong CRC %#x, expected %#x",
494 		    received_crc, computed_crc);
495 		if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
496 		m_freem(m);
497 		return;
498 	} else {
499 		CDCEEM_DEBUG(sc, "received correct CRC %#x", received_crc);
500 	}
501 
502 	uether_rxmbuf(ue, m, pktlen);
503 	*offp = off;
504 }
505 
506 static void
507 cdceem_bulk_read_callback(struct usb_xfer *xfer, usb_error_t usb_error)
508 {
509 	struct cdceem_softc *sc;
510 	struct usb_page_cache *pc;
511 	int actlen, aframes, off;
512 	uint16_t hdr;
513 
514 	sc = usbd_xfer_softc(xfer);
515 	usbd_xfer_status(xfer, &actlen, NULL, &aframes, NULL);
516 
517 	switch (USB_GET_STATE(xfer)) {
518 	case USB_ST_TRANSFERRED:
519 		CDCEEM_DEBUG(sc,
520 		    "received %u bytes in %u frames", actlen, aframes);
521 
522 		pc = usbd_xfer_get_frame(xfer, 0);
523 		off = 0;
524 
525 		while ((off + sizeof(hdr)) <= actlen) {
526 			usbd_copy_out(pc, off, &hdr, sizeof(hdr));
527 			CDCEEM_DEBUG(sc, "hdr = %#x", hdr);
528 			off += sizeof(hdr);
529 
530 			if (hdr == 0) {
531 				CDCEEM_DEBUG(sc, "received Zero Length EEM");
532 				continue;
533 			}
534 
535 			hdr = le16toh(hdr);
536 
537 			if ((hdr & CDCEEM_TYPE_CMD) != 0) {
538 				cdceem_handle_cmd(xfer, hdr, &off);
539 			} else {
540 				cdceem_handle_data(xfer, hdr, &off);
541 			}
542 
543 			KASSERT(off <= actlen,
544 			    ("%s: went past the buffer, off %d, actlen %d",
545 			     __func__, off, actlen));
546 		}
547 
548 		/* FALLTHROUGH */
549 	case USB_ST_SETUP:
550 		CDCEEM_DEBUG(sc, "setup");
551 tr_setup:
552 		usbd_xfer_set_frame_len(xfer, 0, usbd_xfer_max_len(xfer));
553 		usbd_transfer_submit(xfer);
554 		uether_rxflush(&sc->sc_ue);
555 		break;
556 
557 	default:
558 		CDCEEM_WARN(sc, "USB_ST_ERROR: %s", usbd_errstr(usb_error));
559 
560 		if (usb_error != USB_ERR_CANCELLED) {
561 			/* try to clear stall first */
562 			usbd_xfer_set_stall(xfer);
563 			goto tr_setup;
564 		}
565 		break;
566 	}
567 }
568 
569 static void
570 cdceem_send_echo(struct usb_xfer *xfer, int *offp)
571 {
572 	struct cdceem_softc *sc;
573 	struct usb_page_cache *pc;
574 	int maxlen, off;
575 	uint16_t hdr;
576 
577 	off = *offp;
578 	sc = usbd_xfer_softc(xfer);
579 	pc = usbd_xfer_get_frame(xfer, 0);
580 	maxlen = usbd_xfer_max_len(xfer);
581 
582 	CDCEEM_DEBUG(sc, "sending Echo, length %zd",
583 	    sizeof(CDCEEM_ECHO_PAYLOAD));
584 
585 	KASSERT(off + sizeof(hdr) + sizeof(CDCEEM_ECHO_PAYLOAD) < maxlen,
586 	    ("%s: out of space; have %d, need %zd", __func__, maxlen,
587 	    off + sizeof(hdr) + sizeof(CDCEEM_ECHO_PAYLOAD)));
588 
589 	hdr = 0;
590 	hdr |= CDCEEM_TYPE_CMD;
591 	hdr |= CDCEEM_CMD_ECHO;
592 	hdr |= sizeof(CDCEEM_ECHO_PAYLOAD);
593 	CDCEEM_DEBUG(sc, "hdr = %#x", hdr);
594 	hdr = htole16(hdr);
595 
596 	usbd_copy_in(pc, off, &hdr, sizeof(hdr));
597 	off += sizeof(hdr);
598 
599 	usbd_copy_in(pc, off, CDCEEM_ECHO_PAYLOAD,
600 	    sizeof(CDCEEM_ECHO_PAYLOAD));
601 	off += sizeof(CDCEEM_ECHO_PAYLOAD);
602 
603 	sc->sc_flags &= ~CDCEEM_SC_FLAGS_ECHO_PENDING;
604 
605 	*offp = off;
606 }
607 
608 static void
609 cdceem_send_echo_response(struct usb_xfer *xfer, int *offp)
610 {
611 	struct cdceem_softc *sc;
612 	struct usb_page_cache *pc;
613 	int maxlen, off;
614 	uint16_t hdr;
615 
616 	off = *offp;
617 	sc = usbd_xfer_softc(xfer);
618 	pc = usbd_xfer_get_frame(xfer, 0);
619 	maxlen = usbd_xfer_max_len(xfer);
620 
621 	KASSERT(off + sizeof(hdr) + sc->sc_echo_len < maxlen,
622 	    ("%s: out of space; have %d, need %zd", __func__, maxlen,
623 	    off + sizeof(hdr) + sc->sc_echo_len));
624 
625 	CDCEEM_DEBUG(sc, "sending Echo Response, length %zd", sc->sc_echo_len);
626 
627 	hdr = 0;
628 	hdr |= CDCEEM_TYPE_CMD;
629 	hdr |= CDCEEM_CMD_ECHO_RESPONSE;
630 	hdr |= sc->sc_echo_len;
631 	CDCEEM_DEBUG(sc, "hdr = %#x", hdr);
632 	hdr = htole16(hdr);
633 
634 	usbd_copy_in(pc, off, &hdr, sizeof(hdr));
635 	off += sizeof(hdr);
636 
637 	usbd_copy_in(pc, off, sc->sc_echo_buffer, sc->sc_echo_len);
638 	off += sc->sc_echo_len;
639 
640 	sc->sc_flags &= ~CDCEEM_SC_FLAGS_ECHO_RESPONSE_PENDING;
641 	sc->sc_echo_len = 0;
642 
643 	*offp = off;
644 }
645 
646 static void
647 cdceem_send_data(struct usb_xfer *xfer, int *offp)
648 {
649 	struct cdceem_softc *sc;
650 	struct usb_page_cache *pc;
651 	struct ifnet *ifp;
652 	struct mbuf *m;
653 	int maxlen, off;
654 	uint32_t crc;
655 	uint16_t hdr;
656 
657 	off = *offp;
658 	sc = usbd_xfer_softc(xfer);
659 	pc = usbd_xfer_get_frame(xfer, 0);
660 	ifp = uether_getifp(&sc->sc_ue);
661 	maxlen = usbd_xfer_max_len(xfer);
662 
663 	IFQ_DRV_DEQUEUE(&ifp->if_snd, m);
664 	if (m == NULL) {
665 		CDCEEM_DEBUG(sc, "no Data packets to send");
666 		return;
667 	}
668 
669 	KASSERT((m->m_pkthdr.len & CDCEEM_DATA_LEN_MASK) == m->m_pkthdr.len,
670 	    ("%s: packet too long: %d, should be %d\n", __func__,
671 	     m->m_pkthdr.len, m->m_pkthdr.len & CDCEEM_DATA_LEN_MASK));
672 	KASSERT(off + sizeof(hdr) + m->m_pkthdr.len + 4 < maxlen,
673 	    ("%s: out of space; have %d, need %zd", __func__, maxlen,
674 	    off + sizeof(hdr) + m->m_pkthdr.len + 4));
675 
676 	CDCEEM_DEBUG(sc, "sending Data, length %d + 4", m->m_pkthdr.len);
677 
678 	hdr = 0;
679 	if (!cdceem_send_fake_crc)
680 		hdr |= CDCEEM_DATA_CRC;
681 	hdr |= (m->m_pkthdr.len + 4); /* +4 for CRC */
682 	CDCEEM_DEBUG(sc, "hdr = %#x", hdr);
683 	hdr = htole16(hdr);
684 
685 	usbd_copy_in(pc, off, &hdr, sizeof(hdr));
686 	off += sizeof(hdr);
687 
688 	usbd_m_copy_in(pc, off, m, 0, m->m_pkthdr.len);
689 	off += m->m_pkthdr.len;
690 
691 	if (cdceem_send_fake_crc) {
692 		crc = htobe32(0xdeadbeef);
693 	} else {
694 		crc = cdceem_m_crc32(m, 0, m->m_pkthdr.len);
695 	}
696 	CDCEEM_DEBUG(sc, "CRC = %#x", crc);
697 
698 	usbd_copy_in(pc, off, &crc, sizeof(crc));
699 	off += sizeof(crc);
700 
701 	if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
702 
703 	/*
704 	 * If there's a BPF listener, bounce a copy of this frame to it.
705 	 */
706 	BPF_MTAP(ifp, m);
707 	m_freem(m);
708 
709 	*offp = off;
710 }
711 
712 static void
713 cdceem_bulk_write_callback(struct usb_xfer *xfer, usb_error_t usb_error)
714 {
715 	struct cdceem_softc *sc;
716 	struct ifnet *ifp;
717 	int actlen, aframes, maxlen, off;
718 
719 	sc = usbd_xfer_softc(xfer);
720 	maxlen = usbd_xfer_max_len(xfer);
721 
722 	switch (USB_GET_STATE(xfer)) {
723 	case USB_ST_TRANSFERRED:
724 		usbd_xfer_status(xfer, &actlen, NULL, &aframes, NULL);
725 		CDCEEM_DEBUG(sc, "transferred %u bytes in %u frames",
726 		    actlen, aframes);
727 
728 		/* FALLTHROUGH */
729 	case USB_ST_SETUP:
730 		CDCEEM_DEBUG(sc, "setup");
731 tr_setup:
732 
733 		off = 0;
734 		usbd_xfer_set_frame_offset(xfer, 0, 0);
735 
736 		if (sc->sc_flags & CDCEEM_SC_FLAGS_ECHO_PENDING) {
737 			cdceem_send_echo(xfer, &off);
738 		} else if (sc->sc_flags & CDCEEM_SC_FLAGS_ECHO_RESPONSE_PENDING) {
739 			cdceem_send_echo_response(xfer, &off);
740 		} else {
741 			cdceem_send_data(xfer, &off);
742 		}
743 
744 		KASSERT(off <= maxlen,
745 		    ("%s: went past the buffer, off %d, maxlen %d",
746 		     __func__, off, maxlen));
747 
748 		if (off > 0) {
749 			CDCEEM_DEBUG(sc, "starting transfer, length %d", off);
750 			usbd_xfer_set_frame_len(xfer, 0, off);
751 			usbd_transfer_submit(xfer);
752 		} else {
753 			CDCEEM_DEBUG(sc, "nothing to transfer");
754 		}
755 
756 		break;
757 
758 	default:
759 		CDCEEM_WARN(sc, "USB_ST_ERROR: %s", usbd_errstr(usb_error));
760 
761 		ifp = uether_getifp(&sc->sc_ue);
762 		if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
763 
764 		if (usb_error != USB_ERR_CANCELLED) {
765 			/* try to clear stall first */
766 			usbd_xfer_set_stall(xfer);
767 			goto tr_setup;
768 		}
769 		break;
770 	}
771 }
772 
773 static int32_t
774 cdceem_m_crc32_cb(void *arg, void *src, uint32_t count)
775 {
776 	uint32_t *p_crc = arg;
777 
778 	*p_crc = crc32_raw(src, count, *p_crc);
779 	return (0);
780 }
781 
782 static uint32_t
783 cdceem_m_crc32(struct mbuf *m, uint32_t src_offset, uint32_t src_len)
784 {
785 	uint32_t crc = 0xFFFFFFFF;
786 	int error;
787 
788 	error = m_apply(m, src_offset, src_len, cdceem_m_crc32_cb, &crc);
789 	return (crc ^ 0xFFFFFFFF);
790 }
791 
792 static void
793 cdceem_start(struct usb_ether *ue)
794 {
795 	struct cdceem_softc *sc;
796 
797 	sc = uether_getsc(ue);
798 
799 	/*
800 	 * Start the USB transfers, if not already started.
801 	 */
802 	usbd_transfer_start(sc->sc_xfer[CDCEEM_BULK_RX]);
803 	usbd_transfer_start(sc->sc_xfer[CDCEEM_BULK_TX]);
804 }
805 
806 static void
807 cdceem_init(struct usb_ether *ue)
808 {
809 	struct cdceem_softc *sc;
810 	struct ifnet *ifp;
811 
812 	sc = uether_getsc(ue);
813 	ifp = uether_getifp(ue);
814 
815 	ifp->if_drv_flags |= IFF_DRV_RUNNING;
816 
817 	if (cdceem_send_echoes)
818 		sc->sc_flags = CDCEEM_SC_FLAGS_ECHO_PENDING;
819 	else
820 		sc->sc_flags = 0;
821 
822 	/*
823 	 * Stall data write direction, which depends on USB mode.
824 	 *
825 	 * Some USB host stacks (e.g. Mac OS X) don't clears stall
826 	 * bit as it should, so set it in our host mode only.
827 	 */
828 	if (usbd_get_mode(sc->sc_ue.ue_udev) == USB_MODE_HOST)
829 		usbd_xfer_set_stall(sc->sc_xfer[CDCEEM_BULK_TX]);
830 
831 	cdceem_start(ue);
832 }
833 
834 static void
835 cdceem_stop(struct usb_ether *ue)
836 {
837 	struct cdceem_softc *sc;
838 	struct ifnet *ifp;
839 
840 	sc = uether_getsc(ue);
841 	ifp = uether_getifp(ue);
842 
843 	ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
844 
845 	usbd_transfer_stop(sc->sc_xfer[CDCEEM_BULK_RX]);
846 	usbd_transfer_stop(sc->sc_xfer[CDCEEM_BULK_TX]);
847 }
848 
849 static void
850 cdceem_setmulti(struct usb_ether *ue)
851 {
852 	/* no-op */
853 	return;
854 }
855 
856 static void
857 cdceem_setpromisc(struct usb_ether *ue)
858 {
859 	/* no-op */
860 	return;
861 }
862 
863 static int
864 cdceem_suspend(device_t dev)
865 {
866 	struct cdceem_softc *sc = device_get_softc(dev);
867 
868 	CDCEEM_DEBUG(sc, "go");
869 	return (0);
870 }
871 
872 static int
873 cdceem_resume(device_t dev)
874 {
875 	struct cdceem_softc *sc = device_get_softc(dev);
876 
877 	CDCEEM_DEBUG(sc, "go");
878 	return (0);
879 }
880 
881