Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...
[linux-2.6.git] / drivers / net / usb / rndis_host.c
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/mii.h>
26 #include <linux/usb.h>
27 #include <linux/usb/cdc.h>
28 #include <linux/usb/usbnet.h>
29 #include <linux/usb/rndis_host.h>
30
31
32 /*
33  * RNDIS is NDIS remoted over USB.  It's a MSFT variant of CDC ACM ... of
34  * course ACM was intended for modems, not Ethernet links!  USB's standard
35  * for Ethernet links is "CDC Ethernet", which is significantly simpler.
36  *
37  * NOTE that Microsoft's "RNDIS 1.0" specification is incomplete.  Issues
38  * include:
39  *    - Power management in particular relies on information that's scattered
40  *      through other documentation, and which is incomplete or incorrect even
41  *      there.
42  *    - There are various undocumented protocol requirements, such as the
43  *      need to send unused garbage in control-OUT messages.
44  *    - In some cases, MS-Windows will emit undocumented requests; this
45  *      matters more to peripheral implementations than host ones.
46  *
47  * Moreover there's a no-open-specs variant of RNDIS called "ActiveSync".
48  *
49  * For these reasons and others, ** USE OF RNDIS IS STRONGLY DISCOURAGED ** in
50  * favor of such non-proprietary alternatives as CDC Ethernet or the newer (and
51  * currently rare) "Ethernet Emulation Model" (EEM).
52  */
53
54 /*
55  * RNDIS notifications from device: command completion; "reverse"
56  * keepalives; etc
57  */
58 void rndis_status(struct usbnet *dev, struct urb *urb)
59 {
60         devdbg(dev, "rndis status urb, len %d stat %d",
61                 urb->actual_length, urb->status);
62         // FIXME for keepalives, respond immediately (asynchronously)
63         // if not an RNDIS status, do like cdc_status(dev,urb) does
64 }
65 EXPORT_SYMBOL_GPL(rndis_status);
66
67 /*
68  * RPC done RNDIS-style.  Caller guarantees:
69  * - message is properly byteswapped
70  * - there's no other request pending
71  * - buf can hold up to 1KB response (required by RNDIS spec)
72  * On return, the first few entries are already byteswapped.
73  *
74  * Call context is likely probe(), before interface name is known,
75  * which is why we won't try to use it in the diagnostics.
76  */
77 int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf)
78 {
79         struct cdc_state        *info = (void *) &dev->data;
80         int                     master_ifnum;
81         int                     retval;
82         unsigned                count;
83         __le32                  rsp;
84         u32                     xid = 0, msg_len, request_id;
85
86         /* REVISIT when this gets called from contexts other than probe() or
87          * disconnect(): either serialize, or dispatch responses on xid
88          */
89
90         /* Issue the request; xid is unique, don't bother byteswapping it */
91         if (likely(buf->msg_type != RNDIS_MSG_HALT
92                         && buf->msg_type != RNDIS_MSG_RESET)) {
93                 xid = dev->xid++;
94                 if (!xid)
95                         xid = dev->xid++;
96                 buf->request_id = (__force __le32) xid;
97         }
98         master_ifnum = info->control->cur_altsetting->desc.bInterfaceNumber;
99         retval = usb_control_msg(dev->udev,
100                 usb_sndctrlpipe(dev->udev, 0),
101                 USB_CDC_SEND_ENCAPSULATED_COMMAND,
102                 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
103                 0, master_ifnum,
104                 buf, le32_to_cpu(buf->msg_len),
105                 RNDIS_CONTROL_TIMEOUT_MS);
106         if (unlikely(retval < 0 || xid == 0))
107                 return retval;
108
109         // FIXME Seems like some devices discard responses when
110         // we time out and cancel our "get response" requests...
111         // so, this is fragile.  Probably need to poll for status.
112
113         /* ignore status endpoint, just poll the control channel;
114          * the request probably completed immediately
115          */
116         rsp = buf->msg_type | RNDIS_MSG_COMPLETION;
117         for (count = 0; count < 10; count++) {
118                 memset(buf, 0, CONTROL_BUFFER_SIZE);
119                 retval = usb_control_msg(dev->udev,
120                         usb_rcvctrlpipe(dev->udev, 0),
121                         USB_CDC_GET_ENCAPSULATED_RESPONSE,
122                         USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
123                         0, master_ifnum,
124                         buf, CONTROL_BUFFER_SIZE,
125                         RNDIS_CONTROL_TIMEOUT_MS);
126                 if (likely(retval >= 8)) {
127                         msg_len = le32_to_cpu(buf->msg_len);
128                         request_id = (__force u32) buf->request_id;
129                         if (likely(buf->msg_type == rsp)) {
130                                 if (likely(request_id == xid)) {
131                                         if (unlikely(rsp == RNDIS_MSG_RESET_C))
132                                                 return 0;
133                                         if (likely(RNDIS_STATUS_SUCCESS
134                                                         == buf->status))
135                                                 return 0;
136                                         dev_dbg(&info->control->dev,
137                                                 "rndis reply status %08x\n",
138                                                 le32_to_cpu(buf->status));
139                                         return -EL3RST;
140                                 }
141                                 dev_dbg(&info->control->dev,
142                                         "rndis reply id %d expected %d\n",
143                                         request_id, xid);
144                                 /* then likely retry */
145                         } else switch (buf->msg_type) {
146                         case RNDIS_MSG_INDICATE: {      /* fault/event */
147                                 struct rndis_indicate *msg = (void *)buf;
148                                 int state = 0;
149
150                                 switch (msg->status) {
151                                 case RNDIS_STATUS_MEDIA_CONNECT:
152                                         state = 1;
153                                 case RNDIS_STATUS_MEDIA_DISCONNECT:
154                                         dev_info(&info->control->dev,
155                                                 "rndis media %sconnect\n",
156                                                 !state?"dis":"");
157                                         if (dev->driver_info->link_change)
158                                                 dev->driver_info->link_change(
159                                                         dev, state);
160                                         break;
161                                 default:
162                                         dev_info(&info->control->dev,
163                                                 "rndis indication: 0x%08x\n",
164                                                 le32_to_cpu(msg->status));
165                                 }
166                                 }
167                                 break;
168                         case RNDIS_MSG_KEEPALIVE: {     /* ping */
169                                 struct rndis_keepalive_c *msg = (void *)buf;
170
171                                 msg->msg_type = RNDIS_MSG_KEEPALIVE_C;
172                                 msg->msg_len = ccpu2(sizeof *msg);
173                                 msg->status = RNDIS_STATUS_SUCCESS;
174                                 retval = usb_control_msg(dev->udev,
175                                         usb_sndctrlpipe(dev->udev, 0),
176                                         USB_CDC_SEND_ENCAPSULATED_COMMAND,
177                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE,
178                                         0, master_ifnum,
179                                         msg, sizeof *msg,
180                                         RNDIS_CONTROL_TIMEOUT_MS);
181                                 if (unlikely(retval < 0))
182                                         dev_dbg(&info->control->dev,
183                                                 "rndis keepalive err %d\n",
184                                                 retval);
185                                 }
186                                 break;
187                         default:
188                                 dev_dbg(&info->control->dev,
189                                         "unexpected rndis msg %08x len %d\n",
190                                         le32_to_cpu(buf->msg_type), msg_len);
191                         }
192                 } else {
193                         /* device probably issued a protocol stall; ignore */
194                         dev_dbg(&info->control->dev,
195                                 "rndis response error, code %d\n", retval);
196                 }
197                 msleep(2);
198         }
199         dev_dbg(&info->control->dev, "rndis response timeout\n");
200         return -ETIMEDOUT;
201 }
202 EXPORT_SYMBOL_GPL(rndis_command);
203
204 /*
205  * rndis_query:
206  *
207  * Performs a query for @oid along with 0 or more bytes of payload as
208  * specified by @in_len. If @reply_len is not set to -1 then the reply
209  * length is checked against this value, resulting in an error if it
210  * doesn't match.
211  *
212  * NOTE: Adding a payload exactly or greater than the size of the expected
213  * response payload is an evident requirement MSFT added for ActiveSync.
214  *
215  * The only exception is for OIDs that return a variably sized response,
216  * in which case no payload should be added.  This undocumented (and
217  * nonsensical!) issue was found by sniffing protocol requests from the
218  * ActiveSync 4.1 Windows driver.
219  */
220 static int rndis_query(struct usbnet *dev, struct usb_interface *intf,
221                 void *buf, __le32 oid, u32 in_len,
222                 void **reply, int *reply_len)
223 {
224         int retval;
225         union {
226                 void                    *buf;
227                 struct rndis_msg_hdr    *header;
228                 struct rndis_query      *get;
229                 struct rndis_query_c    *get_c;
230         } u;
231         u32 off, len;
232
233         u.buf = buf;
234
235         memset(u.get, 0, sizeof *u.get + in_len);
236         u.get->msg_type = RNDIS_MSG_QUERY;
237         u.get->msg_len = cpu_to_le32(sizeof *u.get + in_len);
238         u.get->oid = oid;
239         u.get->len = cpu_to_le32(in_len);
240         u.get->offset = ccpu2(20);
241
242         retval = rndis_command(dev, u.header);
243         if (unlikely(retval < 0)) {
244                 dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) failed, %d\n",
245                                 oid, retval);
246                 return retval;
247         }
248
249         off = le32_to_cpu(u.get_c->offset);
250         len = le32_to_cpu(u.get_c->len);
251         if (unlikely((8 + off + len) > CONTROL_BUFFER_SIZE))
252                 goto response_error;
253
254         if (*reply_len != -1 && len != *reply_len)
255                 goto response_error;
256
257         *reply = (unsigned char *) &u.get_c->request_id + off;
258         *reply_len = len;
259
260         return retval;
261
262 response_error:
263         dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) "
264                         "invalid response - off %d len %d\n",
265                 oid, off, len);
266         return -EDOM;
267 }
268
269 int
270 generic_rndis_bind(struct usbnet *dev, struct usb_interface *intf, int flags)
271 {
272         int                     retval;
273         struct net_device       *net = dev->net;
274         struct cdc_state        *info = (void *) &dev->data;
275         union {
276                 void                    *buf;
277                 struct rndis_msg_hdr    *header;
278                 struct rndis_init       *init;
279                 struct rndis_init_c     *init_c;
280                 struct rndis_query      *get;
281                 struct rndis_query_c    *get_c;
282                 struct rndis_set        *set;
283                 struct rndis_set_c      *set_c;
284                 struct rndis_halt       *halt;
285         } u;
286         u32                     tmp;
287         __le32                  *phym;
288         int                     reply_len;
289         unsigned char           *bp;
290
291         /* we can't rely on i/o from stack working, or stack allocation */
292         u.buf = kmalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
293         if (!u.buf)
294                 return -ENOMEM;
295         retval = usbnet_generic_cdc_bind(dev, intf);
296         if (retval < 0)
297                 goto fail;
298
299         u.init->msg_type = RNDIS_MSG_INIT;
300         u.init->msg_len = ccpu2(sizeof *u.init);
301         u.init->major_version = ccpu2(1);
302         u.init->minor_version = ccpu2(0);
303
304         /* max transfer (in spec) is 0x4000 at full speed, but for
305          * TX we'll stick to one Ethernet packet plus RNDIS framing.
306          * For RX we handle drivers that zero-pad to end-of-packet.
307          * Don't let userspace change these settings.
308          *
309          * NOTE: there still seems to be wierdness here, as if we need
310          * to do some more things to make sure WinCE targets accept this.
311          * They default to jumbograms of 8KB or 16KB, which is absurd
312          * for such low data rates and which is also more than Linux
313          * can usually expect to allocate for SKB data...
314          */
315         net->hard_header_len += sizeof (struct rndis_data_hdr);
316         dev->hard_mtu = net->mtu + net->hard_header_len;
317
318         dev->maxpacket = usb_maxpacket(dev->udev, dev->out, 1);
319         if (dev->maxpacket == 0) {
320                 if (netif_msg_probe(dev))
321                         dev_dbg(&intf->dev, "dev->maxpacket can't be 0\n");
322                 retval = -EINVAL;
323                 goto fail_and_release;
324         }
325
326         dev->rx_urb_size = dev->hard_mtu + (dev->maxpacket + 1);
327         dev->rx_urb_size &= ~(dev->maxpacket - 1);
328         u.init->max_transfer_size = cpu_to_le32(dev->rx_urb_size);
329
330         net->change_mtu = NULL;
331         retval = rndis_command(dev, u.header);
332         if (unlikely(retval < 0)) {
333                 /* it might not even be an RNDIS device!! */
334                 dev_err(&intf->dev, "RNDIS init failed, %d\n", retval);
335                 goto fail_and_release;
336         }
337         tmp = le32_to_cpu(u.init_c->max_transfer_size);
338         if (tmp < dev->hard_mtu) {
339                 if (tmp <= net->hard_header_len) {
340                         dev_err(&intf->dev,
341                                 "dev can't take %u byte packets (max %u)\n",
342                                 dev->hard_mtu, tmp);
343                         retval = -EINVAL;
344                         goto halt_fail_and_release;
345                 }
346                 dev->hard_mtu = tmp;
347                 net->mtu = dev->hard_mtu - net->hard_header_len;
348                 dev_warn(&intf->dev,
349                          "dev can't take %u byte packets (max %u), "
350                          "adjusting MTU to %u\n",
351                          dev->hard_mtu, tmp, net->mtu);
352         }
353
354         /* REVISIT:  peripheral "alignment" request is ignored ... */
355         dev_dbg(&intf->dev,
356                 "hard mtu %u (%u from dev), rx buflen %Zu, align %d\n",
357                 dev->hard_mtu, tmp, dev->rx_urb_size,
358                 1 << le32_to_cpu(u.init_c->packet_alignment));
359
360         /* module has some device initialization code needs to be done right
361          * after RNDIS_INIT */
362         if (dev->driver_info->early_init &&
363                         dev->driver_info->early_init(dev) != 0)
364                 goto halt_fail_and_release;
365
366         /* Check physical medium */
367         reply_len = sizeof *phym;
368         retval = rndis_query(dev, intf, u.buf, OID_GEN_PHYSICAL_MEDIUM,
369                         0, (void **) &phym, &reply_len);
370         if (retval != 0)
371                 /* OID is optional so don't fail here. */
372                 *phym = RNDIS_PHYSICAL_MEDIUM_UNSPECIFIED;
373         if ((flags & FLAG_RNDIS_PHYM_WIRELESS) &&
374                         *phym != RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
375                 if (netif_msg_probe(dev))
376                         dev_dbg(&intf->dev, "driver requires wireless "
377                                 "physical medium, but device is not.\n");
378                 retval = -ENODEV;
379                 goto halt_fail_and_release;
380         }
381         if ((flags & FLAG_RNDIS_PHYM_NOT_WIRELESS) &&
382                         *phym == RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
383                 if (netif_msg_probe(dev))
384                         dev_dbg(&intf->dev, "driver requires non-wireless "
385                                 "physical medium, but device is wireless.\n");
386                 retval = -ENODEV;
387                 goto halt_fail_and_release;
388         }
389
390         /* Get designated host ethernet address */
391         reply_len = ETH_ALEN;
392         retval = rndis_query(dev, intf, u.buf, OID_802_3_PERMANENT_ADDRESS,
393                         48, (void **) &bp, &reply_len);
394         if (unlikely(retval< 0)) {
395                 dev_err(&intf->dev, "rndis get ethaddr, %d\n", retval);
396                 goto halt_fail_and_release;
397         }
398         memcpy(net->dev_addr, bp, ETH_ALEN);
399
400         /* set a nonzero filter to enable data transfers */
401         memset(u.set, 0, sizeof *u.set);
402         u.set->msg_type = RNDIS_MSG_SET;
403         u.set->msg_len = ccpu2(4 + sizeof *u.set);
404         u.set->oid = OID_GEN_CURRENT_PACKET_FILTER;
405         u.set->len = ccpu2(4);
406         u.set->offset = ccpu2((sizeof *u.set) - 8);
407         *(__le32 *)(u.buf + sizeof *u.set) = RNDIS_DEFAULT_FILTER;
408
409         retval = rndis_command(dev, u.header);
410         if (unlikely(retval < 0)) {
411                 dev_err(&intf->dev, "rndis set packet filter, %d\n", retval);
412                 goto halt_fail_and_release;
413         }
414
415         retval = 0;
416
417         kfree(u.buf);
418         return retval;
419
420 halt_fail_and_release:
421         memset(u.halt, 0, sizeof *u.halt);
422         u.halt->msg_type = RNDIS_MSG_HALT;
423         u.halt->msg_len = ccpu2(sizeof *u.halt);
424         (void) rndis_command(dev, (void *)u.halt);
425 fail_and_release:
426         usb_set_intfdata(info->data, NULL);
427         usb_driver_release_interface(driver_of(intf), info->data);
428         info->data = NULL;
429 fail:
430         kfree(u.buf);
431         return retval;
432 }
433 EXPORT_SYMBOL_GPL(generic_rndis_bind);
434
435 static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
436 {
437         return generic_rndis_bind(dev, intf, FLAG_RNDIS_PHYM_NOT_WIRELESS);
438 }
439
440 void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
441 {
442         struct rndis_halt       *halt;
443
444         /* try to clear any rndis state/activity (no i/o from stack!) */
445         halt = kzalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
446         if (halt) {
447                 halt->msg_type = RNDIS_MSG_HALT;
448                 halt->msg_len = ccpu2(sizeof *halt);
449                 (void) rndis_command(dev, (void *)halt);
450                 kfree(halt);
451         }
452
453         usbnet_cdc_unbind(dev, intf);
454 }
455 EXPORT_SYMBOL_GPL(rndis_unbind);
456
457 /*
458  * DATA -- host must not write zlps
459  */
460 int rndis_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
461 {
462         /* peripheral may have batched packets to us... */
463         while (likely(skb->len)) {
464                 struct rndis_data_hdr   *hdr = (void *)skb->data;
465                 struct sk_buff          *skb2;
466                 u32                     msg_len, data_offset, data_len;
467
468                 msg_len = le32_to_cpu(hdr->msg_len);
469                 data_offset = le32_to_cpu(hdr->data_offset);
470                 data_len = le32_to_cpu(hdr->data_len);
471
472                 /* don't choke if we see oob, per-packet data, etc */
473                 if (unlikely(hdr->msg_type != RNDIS_MSG_PACKET
474                                 || skb->len < msg_len
475                                 || (data_offset + data_len + 8) > msg_len)) {
476                         dev->stats.rx_frame_errors++;
477                         devdbg(dev, "bad rndis message %d/%d/%d/%d, len %d",
478                                 le32_to_cpu(hdr->msg_type),
479                                 msg_len, data_offset, data_len, skb->len);
480                         return 0;
481                 }
482                 skb_pull(skb, 8 + data_offset);
483
484                 /* at most one packet left? */
485                 if (likely((data_len - skb->len) <= sizeof *hdr)) {
486                         skb_trim(skb, data_len);
487                         break;
488                 }
489
490                 /* try to return all the packets in the batch */
491                 skb2 = skb_clone(skb, GFP_ATOMIC);
492                 if (unlikely(!skb2))
493                         break;
494                 skb_pull(skb, msg_len - sizeof *hdr);
495                 skb_trim(skb2, data_len);
496                 usbnet_skb_return(dev, skb2);
497         }
498
499         /* caller will usbnet_skb_return the remaining packet */
500         return 1;
501 }
502 EXPORT_SYMBOL_GPL(rndis_rx_fixup);
503
504 struct sk_buff *
505 rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
506 {
507         struct rndis_data_hdr   *hdr;
508         struct sk_buff          *skb2;
509         unsigned                len = skb->len;
510
511         if (likely(!skb_cloned(skb))) {
512                 int     room = skb_headroom(skb);
513
514                 /* enough head room as-is? */
515                 if (unlikely((sizeof *hdr) <= room))
516                         goto fill;
517
518                 /* enough room, but needs to be readjusted? */
519                 room += skb_tailroom(skb);
520                 if (likely((sizeof *hdr) <= room)) {
521                         skb->data = memmove(skb->head + sizeof *hdr,
522                                             skb->data, len);
523                         skb_set_tail_pointer(skb, len);
524                         goto fill;
525                 }
526         }
527
528         /* create a new skb, with the correct size (and tailpad) */
529         skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
530         dev_kfree_skb_any(skb);
531         if (unlikely(!skb2))
532                 return skb2;
533         skb = skb2;
534
535         /* fill out the RNDIS header.  we won't bother trying to batch
536          * packets; Linux minimizes wasted bandwidth through tx queues.
537          */
538 fill:
539         hdr = (void *) __skb_push(skb, sizeof *hdr);
540         memset(hdr, 0, sizeof *hdr);
541         hdr->msg_type = RNDIS_MSG_PACKET;
542         hdr->msg_len = cpu_to_le32(skb->len);
543         hdr->data_offset = ccpu2(sizeof(*hdr) - 8);
544         hdr->data_len = cpu_to_le32(len);
545
546         /* FIXME make the last packet always be short ... */
547         return skb;
548 }
549 EXPORT_SYMBOL_GPL(rndis_tx_fixup);
550
551
552 static const struct driver_info rndis_info = {
553         .description =  "RNDIS device",
554         .flags =        FLAG_ETHER | FLAG_FRAMING_RN | FLAG_NO_SETINT,
555         .bind =         rndis_bind,
556         .unbind =       rndis_unbind,
557         .status =       rndis_status,
558         .rx_fixup =     rndis_rx_fixup,
559         .tx_fixup =     rndis_tx_fixup,
560 };
561
562 #undef ccpu2
563
564
565 /*-------------------------------------------------------------------------*/
566
567 static const struct usb_device_id       products [] = {
568 {
569         /* RNDIS is MSFT's un-official variant of CDC ACM */
570         USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
571         .driver_info = (unsigned long) &rndis_info,
572 }, {
573         /* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
574         USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
575         .driver_info = (unsigned long) &rndis_info,
576 },
577         { },            // END
578 };
579 MODULE_DEVICE_TABLE(usb, products);
580
581 static struct usb_driver rndis_driver = {
582         .name =         "rndis_host",
583         .id_table =     products,
584         .probe =        usbnet_probe,
585         .disconnect =   usbnet_disconnect,
586         .suspend =      usbnet_suspend,
587         .resume =       usbnet_resume,
588 };
589
590 static int __init rndis_init(void)
591 {
592         return usb_register(&rndis_driver);
593 }
594 module_init(rndis_init);
595
596 static void __exit rndis_exit(void)
597 {
598         usb_deregister(&rndis_driver);
599 }
600 module_exit(rndis_exit);
601
602 MODULE_AUTHOR("David Brownell");
603 MODULE_DESCRIPTION("USB Host side RNDIS driver");
604 MODULE_LICENSE("GPL");