1 /*
2  * Host Side support for RNDIS Networking Links
3  * Copyright (C) 2005 by David Brownell
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  */
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <linux/netdevice.h>
22 #include <linux/etherdevice.h>
23 #include <linux/ethtool.h>
24 #include <linux/workqueue.h>
25 #include <linux/slab.h>
26 #include <linux/mii.h>
27 #include <linux/usb.h>
28 #include <linux/usb/cdc.h>
29 #include <linux/usb/usbnet.h>
30 #include <linux/usb/rndis_host.h>
31 
32 
33 /*
34  * RNDIS is NDIS remoted over USB.  It's a MSFT variant of CDC ACM ... of
35  * course ACM was intended for modems, not Ethernet links!  USB's standard
36  * for Ethernet links is "CDC Ethernet", which is significantly simpler.
37  *
38  * NOTE that Microsoft's "RNDIS 1.0" specification is incomplete.  Issues
39  * include:
40  *    - Power management in particular relies on information that's scattered
41  *	through other documentation, and which is incomplete or incorrect even
42  *	there.
43  *    - There are various undocumented protocol requirements, such as the
44  *	need to send unused garbage in control-OUT messages.
45  *    - In some cases, MS-Windows will emit undocumented requests; this
46  *	matters more to peripheral implementations than host ones.
47  *
48  * Moreover there's a no-open-specs variant of RNDIS called "ActiveSync".
49  *
50  * For these reasons and others, ** USE OF RNDIS IS STRONGLY DISCOURAGED ** in
51  * favor of such non-proprietary alternatives as CDC Ethernet or the newer (and
52  * currently rare) "Ethernet Emulation Model" (EEM).
53  */
54 
55 /*
56  * RNDIS notifications from device: command completion; "reverse"
57  * keepalives; etc
58  */
rndis_status(struct usbnet * dev,struct urb * urb)59 void rndis_status(struct usbnet *dev, struct urb *urb)
60 {
61 	netdev_dbg(dev->net, "rndis status urb, len %d stat %d\n",
62 		   urb->actual_length, urb->status);
63 	// FIXME for keepalives, respond immediately (asynchronously)
64 	// if not an RNDIS status, do like cdc_status(dev,urb) does
65 }
66 EXPORT_SYMBOL_GPL(rndis_status);
67 
68 /*
69  * RNDIS indicate messages.
70  */
rndis_msg_indicate(struct usbnet * dev,struct rndis_indicate * msg,int buflen)71 static void rndis_msg_indicate(struct usbnet *dev, struct rndis_indicate *msg,
72 				int buflen)
73 {
74 	struct cdc_state *info = (void *)&dev->data;
75 	struct device *udev = &info->control->dev;
76 
77 	if (dev->driver_info->indication) {
78 		dev->driver_info->indication(dev, msg, buflen);
79 	} else {
80 		switch (msg->status) {
81 		case RNDIS_STATUS_MEDIA_CONNECT:
82 			dev_info(udev, "rndis media connect\n");
83 			break;
84 		case RNDIS_STATUS_MEDIA_DISCONNECT:
85 			dev_info(udev, "rndis media disconnect\n");
86 			break;
87 		default:
88 			dev_info(udev, "rndis indication: 0x%08x\n",
89 					le32_to_cpu(msg->status));
90 		}
91 	}
92 }
93 
94 /*
95  * RPC done RNDIS-style.  Caller guarantees:
96  * - message is properly byteswapped
97  * - there's no other request pending
98  * - buf can hold up to 1KB response (required by RNDIS spec)
99  * On return, the first few entries are already byteswapped.
100  *
101  * Call context is likely probe(), before interface name is known,
102  * which is why we won't try to use it in the diagnostics.
103  */
rndis_command(struct usbnet * dev,struct rndis_msg_hdr * buf,int buflen)104 int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf, int buflen)
105 {
106 	struct cdc_state	*info = (void *) &dev->data;
107 	int			master_ifnum;
108 	int			retval;
109 	unsigned		count;
110 	__le32			rsp;
111 	u32			xid = 0, msg_len, request_id;
112 
113 	/* REVISIT when this gets called from contexts other than probe() or
114 	 * disconnect(): either serialize, or dispatch responses on xid
115 	 */
116 
117 	/* Issue the request; xid is unique, don't bother byteswapping it */
118 	if (likely(buf->msg_type != RNDIS_MSG_HALT &&
119 		   buf->msg_type != RNDIS_MSG_RESET)) {
120 		xid = dev->xid++;
121 		if (!xid)
122 			xid = dev->xid++;
123 		buf->request_id = (__force __le32) xid;
124 	}
125 	master_ifnum = info->control->cur_altsetting->desc.bInterfaceNumber;
126 	retval = usb_control_msg(dev->udev,
127 		usb_sndctrlpipe(dev->udev, 0),
128 		USB_CDC_SEND_ENCAPSULATED_COMMAND,
129 		USB_TYPE_CLASS | USB_RECIP_INTERFACE,
130 		0, master_ifnum,
131 		buf, le32_to_cpu(buf->msg_len),
132 		RNDIS_CONTROL_TIMEOUT_MS);
133 	if (unlikely(retval < 0 || xid == 0))
134 		return retval;
135 
136 	// FIXME Seems like some devices discard responses when
137 	// we time out and cancel our "get response" requests...
138 	// so, this is fragile.  Probably need to poll for status.
139 
140 	/* ignore status endpoint, just poll the control channel;
141 	 * the request probably completed immediately
142 	 */
143 	rsp = buf->msg_type | RNDIS_MSG_COMPLETION;
144 	for (count = 0; count < 10; count++) {
145 		memset(buf, 0, CONTROL_BUFFER_SIZE);
146 		retval = usb_control_msg(dev->udev,
147 			usb_rcvctrlpipe(dev->udev, 0),
148 			USB_CDC_GET_ENCAPSULATED_RESPONSE,
149 			USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
150 			0, master_ifnum,
151 			buf, buflen,
152 			RNDIS_CONTROL_TIMEOUT_MS);
153 		if (likely(retval >= 8)) {
154 			msg_len = le32_to_cpu(buf->msg_len);
155 			request_id = (__force u32) buf->request_id;
156 			if (likely(buf->msg_type == rsp)) {
157 				if (likely(request_id == xid)) {
158 					if (unlikely(rsp == RNDIS_MSG_RESET_C))
159 						return 0;
160 					if (likely(RNDIS_STATUS_SUCCESS
161 							== buf->status))
162 						return 0;
163 					dev_dbg(&info->control->dev,
164 						"rndis reply status %08x\n",
165 						le32_to_cpu(buf->status));
166 					return -EL3RST;
167 				}
168 				dev_dbg(&info->control->dev,
169 					"rndis reply id %d expected %d\n",
170 					request_id, xid);
171 				/* then likely retry */
172 			} else switch (buf->msg_type) {
173 			case RNDIS_MSG_INDICATE:	/* fault/event */
174 				rndis_msg_indicate(dev, (void *)buf, buflen);
175 
176 				break;
177 			case RNDIS_MSG_KEEPALIVE: {	/* ping */
178 				struct rndis_keepalive_c *msg = (void *)buf;
179 
180 				msg->msg_type = RNDIS_MSG_KEEPALIVE_C;
181 				msg->msg_len = cpu_to_le32(sizeof *msg);
182 				msg->status = RNDIS_STATUS_SUCCESS;
183 				retval = usb_control_msg(dev->udev,
184 					usb_sndctrlpipe(dev->udev, 0),
185 					USB_CDC_SEND_ENCAPSULATED_COMMAND,
186 					USB_TYPE_CLASS | USB_RECIP_INTERFACE,
187 					0, master_ifnum,
188 					msg, sizeof *msg,
189 					RNDIS_CONTROL_TIMEOUT_MS);
190 				if (unlikely(retval < 0))
191 					dev_dbg(&info->control->dev,
192 						"rndis keepalive err %d\n",
193 						retval);
194 				}
195 				break;
196 			default:
197 				dev_dbg(&info->control->dev,
198 					"unexpected rndis msg %08x len %d\n",
199 					le32_to_cpu(buf->msg_type), msg_len);
200 			}
201 		} else {
202 			/* device probably issued a protocol stall; ignore */
203 			dev_dbg(&info->control->dev,
204 				"rndis response error, code %d\n", retval);
205 		}
206 		msleep(20);
207 	}
208 	dev_dbg(&info->control->dev, "rndis response timeout\n");
209 	return -ETIMEDOUT;
210 }
211 EXPORT_SYMBOL_GPL(rndis_command);
212 
213 /*
214  * rndis_query:
215  *
216  * Performs a query for @oid along with 0 or more bytes of payload as
217  * specified by @in_len. If @reply_len is not set to -1 then the reply
218  * length is checked against this value, resulting in an error if it
219  * doesn't match.
220  *
221  * NOTE: Adding a payload exactly or greater than the size of the expected
222  * response payload is an evident requirement MSFT added for ActiveSync.
223  *
224  * The only exception is for OIDs that return a variably sized response,
225  * in which case no payload should be added.  This undocumented (and
226  * nonsensical!) issue was found by sniffing protocol requests from the
227  * ActiveSync 4.1 Windows driver.
228  */
rndis_query(struct usbnet * dev,struct usb_interface * intf,void * buf,__le32 oid,u32 in_len,void ** reply,int * reply_len)229 static int rndis_query(struct usbnet *dev, struct usb_interface *intf,
230 		void *buf, __le32 oid, u32 in_len,
231 		void **reply, int *reply_len)
232 {
233 	int retval;
234 	union {
235 		void			*buf;
236 		struct rndis_msg_hdr	*header;
237 		struct rndis_query	*get;
238 		struct rndis_query_c	*get_c;
239 	} u;
240 	u32 off, len;
241 
242 	u.buf = buf;
243 
244 	memset(u.get, 0, sizeof *u.get + in_len);
245 	u.get->msg_type = RNDIS_MSG_QUERY;
246 	u.get->msg_len = cpu_to_le32(sizeof *u.get + in_len);
247 	u.get->oid = oid;
248 	u.get->len = cpu_to_le32(in_len);
249 	u.get->offset = cpu_to_le32(20);
250 
251 	retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
252 	if (unlikely(retval < 0)) {
253 		dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) failed, %d\n",
254 				oid, retval);
255 		return retval;
256 	}
257 
258 	off = le32_to_cpu(u.get_c->offset);
259 	len = le32_to_cpu(u.get_c->len);
260 	if (unlikely((8 + off + len) > CONTROL_BUFFER_SIZE))
261 		goto response_error;
262 
263 	if (*reply_len != -1 && len != *reply_len)
264 		goto response_error;
265 
266 	*reply = (unsigned char *) &u.get_c->request_id + off;
267 	*reply_len = len;
268 
269 	return retval;
270 
271 response_error:
272 	dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) "
273 			"invalid response - off %d len %d\n",
274 		oid, off, len);
275 	return -EDOM;
276 }
277 
278 /* same as usbnet_netdev_ops but MTU change not allowed */
279 static const struct net_device_ops rndis_netdev_ops = {
280 	.ndo_open		= usbnet_open,
281 	.ndo_stop		= usbnet_stop,
282 	.ndo_start_xmit		= usbnet_start_xmit,
283 	.ndo_tx_timeout		= usbnet_tx_timeout,
284 	.ndo_set_mac_address 	= eth_mac_addr,
285 	.ndo_validate_addr	= eth_validate_addr,
286 };
287 
288 int
generic_rndis_bind(struct usbnet * dev,struct usb_interface * intf,int flags)289 generic_rndis_bind(struct usbnet *dev, struct usb_interface *intf, int flags)
290 {
291 	int			retval;
292 	struct net_device	*net = dev->net;
293 	struct cdc_state	*info = (void *) &dev->data;
294 	union {
295 		void			*buf;
296 		struct rndis_msg_hdr	*header;
297 		struct rndis_init	*init;
298 		struct rndis_init_c	*init_c;
299 		struct rndis_query	*get;
300 		struct rndis_query_c	*get_c;
301 		struct rndis_set	*set;
302 		struct rndis_set_c	*set_c;
303 		struct rndis_halt	*halt;
304 	} u;
305 	u32			tmp;
306 	__le32			phym_unspec, *phym;
307 	int			reply_len;
308 	unsigned char		*bp;
309 
310 	/* we can't rely on i/o from stack working, or stack allocation */
311 	u.buf = kmalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
312 	if (!u.buf)
313 		return -ENOMEM;
314 	retval = usbnet_generic_cdc_bind(dev, intf);
315 	if (retval < 0)
316 		goto fail;
317 
318 	u.init->msg_type = RNDIS_MSG_INIT;
319 	u.init->msg_len = cpu_to_le32(sizeof *u.init);
320 	u.init->major_version = cpu_to_le32(1);
321 	u.init->minor_version = cpu_to_le32(0);
322 
323 	/* max transfer (in spec) is 0x4000 at full speed, but for
324 	 * TX we'll stick to one Ethernet packet plus RNDIS framing.
325 	 * For RX we handle drivers that zero-pad to end-of-packet.
326 	 * Don't let userspace change these settings.
327 	 *
328 	 * NOTE: there still seems to be wierdness here, as if we need
329 	 * to do some more things to make sure WinCE targets accept this.
330 	 * They default to jumbograms of 8KB or 16KB, which is absurd
331 	 * for such low data rates and which is also more than Linux
332 	 * can usually expect to allocate for SKB data...
333 	 */
334 	net->hard_header_len += sizeof (struct rndis_data_hdr);
335 	dev->hard_mtu = net->mtu + net->hard_header_len;
336 
337 	dev->maxpacket = usb_maxpacket(dev->udev, dev->out, 1);
338 	if (dev->maxpacket == 0) {
339 		netif_dbg(dev, probe, dev->net,
340 			  "dev->maxpacket can't be 0\n");
341 		retval = -EINVAL;
342 		goto fail_and_release;
343 	}
344 
345 	dev->rx_urb_size = dev->hard_mtu + (dev->maxpacket + 1);
346 	dev->rx_urb_size &= ~(dev->maxpacket - 1);
347 	u.init->max_transfer_size = cpu_to_le32(dev->rx_urb_size);
348 
349 	net->netdev_ops = &rndis_netdev_ops;
350 
351 	retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
352 	if (unlikely(retval < 0)) {
353 		/* it might not even be an RNDIS device!! */
354 		dev_err(&intf->dev, "RNDIS init failed, %d\n", retval);
355 		goto fail_and_release;
356 	}
357 	tmp = le32_to_cpu(u.init_c->max_transfer_size);
358 	if (tmp < dev->hard_mtu) {
359 		if (tmp <= net->hard_header_len) {
360 			dev_err(&intf->dev,
361 				"dev can't take %u byte packets (max %u)\n",
362 				dev->hard_mtu, tmp);
363 			retval = -EINVAL;
364 			goto halt_fail_and_release;
365 		}
366 		dev_warn(&intf->dev,
367 			 "dev can't take %u byte packets (max %u), "
368 			 "adjusting MTU to %u\n",
369 			 dev->hard_mtu, tmp, tmp - net->hard_header_len);
370 		dev->hard_mtu = tmp;
371 		net->mtu = dev->hard_mtu - net->hard_header_len;
372 	}
373 
374 	/* REVISIT:  peripheral "alignment" request is ignored ... */
375 	dev_dbg(&intf->dev,
376 		"hard mtu %u (%u from dev), rx buflen %Zu, align %d\n",
377 		dev->hard_mtu, tmp, dev->rx_urb_size,
378 		1 << le32_to_cpu(u.init_c->packet_alignment));
379 
380 	/* module has some device initialization code needs to be done right
381 	 * after RNDIS_INIT */
382 	if (dev->driver_info->early_init &&
383 			dev->driver_info->early_init(dev) != 0)
384 		goto halt_fail_and_release;
385 
386 	/* Check physical medium */
387 	phym = NULL;
388 	reply_len = sizeof *phym;
389 	retval = rndis_query(dev, intf, u.buf, OID_GEN_PHYSICAL_MEDIUM,
390 			0, (void **) &phym, &reply_len);
391 	if (retval != 0 || !phym) {
392 		/* OID is optional so don't fail here. */
393 		phym_unspec = RNDIS_PHYSICAL_MEDIUM_UNSPECIFIED;
394 		phym = &phym_unspec;
395 	}
396 	if ((flags & FLAG_RNDIS_PHYM_WIRELESS) &&
397 			*phym != RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
398 		netif_dbg(dev, probe, dev->net,
399 			  "driver requires wireless physical medium, but device is not\n");
400 		retval = -ENODEV;
401 		goto halt_fail_and_release;
402 	}
403 	if ((flags & FLAG_RNDIS_PHYM_NOT_WIRELESS) &&
404 			*phym == RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
405 		netif_dbg(dev, probe, dev->net,
406 			  "driver requires non-wireless physical medium, but device is wireless.\n");
407 		retval = -ENODEV;
408 		goto halt_fail_and_release;
409 	}
410 
411 	/* Get designated host ethernet address */
412 	reply_len = ETH_ALEN;
413 	retval = rndis_query(dev, intf, u.buf, OID_802_3_PERMANENT_ADDRESS,
414 			48, (void **) &bp, &reply_len);
415 	if (unlikely(retval< 0)) {
416 		dev_err(&intf->dev, "rndis get ethaddr, %d\n", retval);
417 		goto halt_fail_and_release;
418 	}
419 	memcpy(net->dev_addr, bp, ETH_ALEN);
420 	memcpy(net->perm_addr, bp, ETH_ALEN);
421 
422 	/* set a nonzero filter to enable data transfers */
423 	memset(u.set, 0, sizeof *u.set);
424 	u.set->msg_type = RNDIS_MSG_SET;
425 	u.set->msg_len = cpu_to_le32(4 + sizeof *u.set);
426 	u.set->oid = OID_GEN_CURRENT_PACKET_FILTER;
427 	u.set->len = cpu_to_le32(4);
428 	u.set->offset = cpu_to_le32((sizeof *u.set) - 8);
429 	*(__le32 *)(u.buf + sizeof *u.set) = RNDIS_DEFAULT_FILTER;
430 
431 	retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
432 	if (unlikely(retval < 0)) {
433 		dev_err(&intf->dev, "rndis set packet filter, %d\n", retval);
434 		goto halt_fail_and_release;
435 	}
436 
437 	retval = 0;
438 
439 	kfree(u.buf);
440 	return retval;
441 
442 halt_fail_and_release:
443 	memset(u.halt, 0, sizeof *u.halt);
444 	u.halt->msg_type = RNDIS_MSG_HALT;
445 	u.halt->msg_len = cpu_to_le32(sizeof *u.halt);
446 	(void) rndis_command(dev, (void *)u.halt, CONTROL_BUFFER_SIZE);
447 fail_and_release:
448 	usb_set_intfdata(info->data, NULL);
449 	usb_driver_release_interface(driver_of(intf), info->data);
450 	info->data = NULL;
451 fail:
452 	kfree(u.buf);
453 	return retval;
454 }
455 EXPORT_SYMBOL_GPL(generic_rndis_bind);
456 
rndis_bind(struct usbnet * dev,struct usb_interface * intf)457 static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
458 {
459 	return generic_rndis_bind(dev, intf, FLAG_RNDIS_PHYM_NOT_WIRELESS);
460 }
461 
rndis_unbind(struct usbnet * dev,struct usb_interface * intf)462 void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
463 {
464 	struct rndis_halt	*halt;
465 
466 	/* try to clear any rndis state/activity (no i/o from stack!) */
467 	halt = kzalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
468 	if (halt) {
469 		halt->msg_type = RNDIS_MSG_HALT;
470 		halt->msg_len = cpu_to_le32(sizeof *halt);
471 		(void) rndis_command(dev, (void *)halt, CONTROL_BUFFER_SIZE);
472 		kfree(halt);
473 	}
474 
475 	usbnet_cdc_unbind(dev, intf);
476 }
477 EXPORT_SYMBOL_GPL(rndis_unbind);
478 
479 /*
480  * DATA -- host must not write zlps
481  */
rndis_rx_fixup(struct usbnet * dev,struct sk_buff * skb)482 int rndis_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
483 {
484 	/* peripheral may have batched packets to us... */
485 	while (likely(skb->len)) {
486 		struct rndis_data_hdr	*hdr = (void *)skb->data;
487 		struct sk_buff		*skb2;
488 		u32			msg_len, data_offset, data_len;
489 
490 		msg_len = le32_to_cpu(hdr->msg_len);
491 		data_offset = le32_to_cpu(hdr->data_offset);
492 		data_len = le32_to_cpu(hdr->data_len);
493 
494 		/* don't choke if we see oob, per-packet data, etc */
495 		if (unlikely(hdr->msg_type != RNDIS_MSG_PACKET ||
496 			     skb->len < msg_len ||
497 			     (data_offset + data_len + 8) > msg_len)) {
498 			dev->net->stats.rx_frame_errors++;
499 			netdev_dbg(dev->net, "bad rndis message %d/%d/%d/%d, len %d\n",
500 				   le32_to_cpu(hdr->msg_type),
501 				   msg_len, data_offset, data_len, skb->len);
502 			return 0;
503 		}
504 		skb_pull(skb, 8 + data_offset);
505 
506 		/* at most one packet left? */
507 		if (likely((data_len - skb->len) <= sizeof *hdr)) {
508 			skb_trim(skb, data_len);
509 			break;
510 		}
511 
512 		/* try to return all the packets in the batch */
513 		skb2 = skb_clone(skb, GFP_ATOMIC);
514 		if (unlikely(!skb2))
515 			break;
516 		skb_pull(skb, msg_len - sizeof *hdr);
517 		skb_trim(skb2, data_len);
518 		usbnet_skb_return(dev, skb2);
519 	}
520 
521 	/* caller will usbnet_skb_return the remaining packet */
522 	return 1;
523 }
524 EXPORT_SYMBOL_GPL(rndis_rx_fixup);
525 
526 struct sk_buff *
rndis_tx_fixup(struct usbnet * dev,struct sk_buff * skb,gfp_t flags)527 rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
528 {
529 	struct rndis_data_hdr	*hdr;
530 	struct sk_buff		*skb2;
531 	unsigned		len = skb->len;
532 
533 	if (likely(!skb_cloned(skb))) {
534 		int	room = skb_headroom(skb);
535 
536 		/* enough head room as-is? */
537 		if (unlikely((sizeof *hdr) <= room))
538 			goto fill;
539 
540 		/* enough room, but needs to be readjusted? */
541 		room += skb_tailroom(skb);
542 		if (likely((sizeof *hdr) <= room)) {
543 			skb->data = memmove(skb->head + sizeof *hdr,
544 					    skb->data, len);
545 			skb_set_tail_pointer(skb, len);
546 			goto fill;
547 		}
548 	}
549 
550 	/* create a new skb, with the correct size (and tailpad) */
551 	skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
552 	dev_kfree_skb_any(skb);
553 	if (unlikely(!skb2))
554 		return skb2;
555 	skb = skb2;
556 
557 	/* fill out the RNDIS header.  we won't bother trying to batch
558 	 * packets; Linux minimizes wasted bandwidth through tx queues.
559 	 */
560 fill:
561 	hdr = (void *) __skb_push(skb, sizeof *hdr);
562 	memset(hdr, 0, sizeof *hdr);
563 	hdr->msg_type = RNDIS_MSG_PACKET;
564 	hdr->msg_len = cpu_to_le32(skb->len);
565 	hdr->data_offset = cpu_to_le32(sizeof(*hdr) - 8);
566 	hdr->data_len = cpu_to_le32(len);
567 
568 	/* FIXME make the last packet always be short ... */
569 	return skb;
570 }
571 EXPORT_SYMBOL_GPL(rndis_tx_fixup);
572 
573 
574 static const struct driver_info	rndis_info = {
575 	.description =	"RNDIS device",
576 	.flags =	FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_FRAMING_RN | FLAG_NO_SETINT,
577 	.bind =		rndis_bind,
578 	.unbind =	rndis_unbind,
579 	.status =	rndis_status,
580 	.rx_fixup =	rndis_rx_fixup,
581 	.tx_fixup =	rndis_tx_fixup,
582 };
583 
584 /*-------------------------------------------------------------------------*/
585 
586 static const struct usb_device_id	products [] = {
587 {
588 	/* RNDIS is MSFT's un-official variant of CDC ACM */
589 	USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
590 	.driver_info = (unsigned long) &rndis_info,
591 }, {
592 	/* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
593 	USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
594 	.driver_info = (unsigned long) &rndis_info,
595 }, {
596 	/* RNDIS for tethering */
597 	USB_INTERFACE_INFO(USB_CLASS_WIRELESS_CONTROLLER, 1, 3),
598 	.driver_info = (unsigned long) &rndis_info,
599 },
600 	{ },		// END
601 };
602 MODULE_DEVICE_TABLE(usb, products);
603 
604 static struct usb_driver rndis_driver = {
605 	.name =		"rndis_host",
606 	.id_table =	products,
607 	.probe =	usbnet_probe,
608 	.disconnect =	usbnet_disconnect,
609 	.suspend =	usbnet_suspend,
610 	.resume =	usbnet_resume,
611 };
612 
rndis_init(void)613 static int __init rndis_init(void)
614 {
615 	return usb_register(&rndis_driver);
616 }
617 module_init(rndis_init);
618 
rndis_exit(void)619 static void __exit rndis_exit(void)
620 {
621 	usb_deregister(&rndis_driver);
622 }
623 module_exit(rndis_exit);
624 
625 MODULE_AUTHOR("David Brownell");
626 MODULE_DESCRIPTION("USB Host side RNDIS driver");
627 MODULE_LICENSE("GPL");
628