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, int buflen)
  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, buflen,
 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 = cpu_to_le32(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(20);
 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 = cpu_to_le32(20);
 241
 242         retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 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 /* same as usbnet_netdev_ops but MTU change not allowed */
 270 static const struct net_device_ops rndis_netdev_ops = {
 271         .ndo_open               = usbnet_open,
 272         .ndo_stop               = usbnet_stop,
 273         .ndo_start_xmit         = usbnet_start_xmit,
 274         .ndo_tx_timeout         = usbnet_tx_timeout,
 275         .ndo_set_mac_address    = eth_mac_addr,
 276         .ndo_validate_addr      = eth_validate_addr,
 277 };
 278
 279 int
 280 generic_rndis_bind(struct usbnet *dev, struct usb_interface *intf, int flags)
 281 {
 282         int                     retval;
 283         struct net_device       *net = dev->net;
 284         struct cdc_state        *info = (void *) &dev->data;
 285         union {
 286                 void                    *buf;
 287                 struct rndis_msg_hdr    *header;
 288                 struct rndis_init       *init;
 289                 struct rndis_init_c     *init_c;
 290                 struct rndis_query      *get;
 291                 struct rndis_query_c    *get_c;
 292                 struct rndis_set        *set;
 293                 struct rndis_set_c      *set_c;
 294                 struct rndis_halt       *halt;
 295         } u;
 296         u32                     tmp;
 297         __le32                  phym_unspec, *phym;
 298         int                     reply_len;
 299         unsigned char           *bp;
 300
 301         /* we can't rely on i/o from stack working, or stack allocation */
 302         u.buf = kmalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 303         if (!u.buf)
 304                 return -ENOMEM;
 305         retval = usbnet_generic_cdc_bind(dev, intf);
 306         if (retval < 0)
 307                 goto fail;
 308
 309         u.init->msg_type = RNDIS_MSG_INIT;
 310         u.init->msg_len = cpu_to_le32(sizeof *u.init);
 311         u.init->major_version = cpu_to_le32(1);
 312         u.init->minor_version = cpu_to_le32(0);
 313
 314         /* max transfer (in spec) is 0x4000 at full speed, but for
 315          * TX we'll stick to one Ethernet packet plus RNDIS framing.
 316          * For RX we handle drivers that zero-pad to end-of-packet.
 317          * Don't let userspace change these settings.
 318          *
 319          * NOTE: there still seems to be wierdness here, as if we need
 320          * to do some more things to make sure WinCE targets accept this.
 321          * They default to jumbograms of 8KB or 16KB, which is absurd
 322          * for such low data rates and which is also more than Linux
 323          * can usually expect to allocate for SKB data...
 324          */
 325         net->hard_header_len += sizeof (struct rndis_data_hdr);
 326         dev->hard_mtu = net->mtu + net->hard_header_len;
 327
 328         dev->maxpacket = usb_maxpacket(dev->udev, dev->out, 1);
 329         if (dev->maxpacket == 0) {
 330                 if (netif_msg_probe(dev))
 331                         dev_dbg(&intf->dev, "dev->maxpacket can't be 0\n");
 332                 retval = -EINVAL;
 333                 goto fail_and_release;
 334         }
 335
 336         dev->rx_urb_size = dev->hard_mtu + (dev->maxpacket + 1);
 337         dev->rx_urb_size &= ~(dev->maxpacket - 1);
 338         u.init->max_transfer_size = cpu_to_le32(dev->rx_urb_size);
 339
 340         net->netdev_ops = &rndis_netdev_ops;
 341
 342         retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 343         if (unlikely(retval < 0)) {
 344                 /* it might not even be an RNDIS device!! */
 345                 dev_err(&intf->dev, "RNDIS init failed, %d\n", retval);
 346                 goto fail_and_release;
 347         }
 348         tmp = le32_to_cpu(u.init_c->max_transfer_size);
 349         if (tmp < dev->hard_mtu) {
 350                 if (tmp <= net->hard_header_len) {
 351                         dev_err(&intf->dev,
 352                                 "dev can't take %u byte packets (max %u)\n",
 353                                 dev->hard_mtu, tmp);
 354                         retval = -EINVAL;
 355                         goto halt_fail_and_release;
 356                 }
 357                 dev->hard_mtu = tmp;
 358                 net->mtu = dev->hard_mtu - net->hard_header_len;
 359                 dev_warn(&intf->dev,
 360                          "dev can't take %u byte packets (max %u), "
 361                          "adjusting MTU to %u\n",
 362                          dev->hard_mtu, tmp, net->mtu);
 363         }
 364
 365         /* REVISIT:  peripheral "alignment" request is ignored ... */
 366         dev_dbg(&intf->dev,
 367                 "hard mtu %u (%u from dev), rx buflen %Zu, align %d\n",
 368                 dev->hard_mtu, tmp, dev->rx_urb_size,
 369                 1 << le32_to_cpu(u.init_c->packet_alignment));
 370
 371         /* module has some device initialization code needs to be done right
 372          * after RNDIS_INIT */
 373         if (dev->driver_info->early_init &&
 374                         dev->driver_info->early_init(dev) != 0)
 375                 goto halt_fail_and_release;
 376
 377         /* Check physical medium */
 378         phym = NULL;
 379         reply_len = sizeof *phym;
 380         retval = rndis_query(dev, intf, u.buf, OID_GEN_PHYSICAL_MEDIUM,
 381                         0, (void **) &phym, &reply_len);
 382         if (retval != 0 || !phym) {
 383                 /* OID is optional so don't fail here. */
 384                 phym_unspec = RNDIS_PHYSICAL_MEDIUM_UNSPECIFIED;
 385                 phym = &phym_unspec;
 386         }
 387         if ((flags & FLAG_RNDIS_PHYM_WIRELESS) &&
 388                         *phym != RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
 389                 if (netif_msg_probe(dev))
 390                         dev_dbg(&intf->dev, "driver requires wireless "
 391                                 "physical medium, but device is not.\n");
 392                 retval = -ENODEV;
 393                 goto halt_fail_and_release;
 394         }
 395         if ((flags & FLAG_RNDIS_PHYM_NOT_WIRELESS) &&
 396                         *phym == RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
 397                 if (netif_msg_probe(dev))
 398                         dev_dbg(&intf->dev, "driver requires non-wireless "
 399                                 "physical medium, but device is wireless.\n");
 400                 retval = -ENODEV;
 401                 goto halt_fail_and_release;
 402         }
 403
 404         /* Get designated host ethernet address */
 405         reply_len = ETH_ALEN;
 406         retval = rndis_query(dev, intf, u.buf, OID_802_3_PERMANENT_ADDRESS,
 407                         48, (void **) &bp, &reply_len);
 408         if (unlikely(retval< 0)) {
 409                 dev_err(&intf->dev, "rndis get ethaddr, %d\n", retval);
 410                 goto halt_fail_and_release;
 411         }
 412         memcpy(net->dev_addr, bp, ETH_ALEN);
 413
 414         /* set a nonzero filter to enable data transfers */
 415         memset(u.set, 0, sizeof *u.set);
 416         u.set->msg_type = RNDIS_MSG_SET;
 417         u.set->msg_len = cpu_to_le32(4 + sizeof *u.set);
 418         u.set->oid = OID_GEN_CURRENT_PACKET_FILTER;
 419         u.set->len = cpu_to_le32(4);
 420         u.set->offset = cpu_to_le32((sizeof *u.set) - 8);
 421         *(__le32 *)(u.buf + sizeof *u.set) = RNDIS_DEFAULT_FILTER;
 422
 423         retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 424         if (unlikely(retval < 0)) {
 425                 dev_err(&intf->dev, "rndis set packet filter, %d\n", retval);
 426                 goto halt_fail_and_release;
 427         }
 428
 429         retval = 0;
 430
 431         kfree(u.buf);
 432         return retval;
 433
 434 halt_fail_and_release:
 435         memset(u.halt, 0, sizeof *u.halt);
 436         u.halt->msg_type = RNDIS_MSG_HALT;
 437         u.halt->msg_len = cpu_to_le32(sizeof *u.halt);
 438         (void) rndis_command(dev, (void *)u.halt, CONTROL_BUFFER_SIZE);
 439 fail_and_release:
 440         usb_set_intfdata(info->data, NULL);
 441         usb_driver_release_interface(driver_of(intf), info->data);
 442         info->data = NULL;
 443 fail:
 444         kfree(u.buf);
 445         return retval;
 446 }
 447 EXPORT_SYMBOL_GPL(generic_rndis_bind);
 448
 449 static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
 450 {
 451         return generic_rndis_bind(dev, intf, FLAG_RNDIS_PHYM_NOT_WIRELESS);
 452 }
 453
 454 void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
 455 {
 456         struct rndis_halt       *halt;
 457
 458         /* try to clear any rndis state/activity (no i/o from stack!) */
 459         halt = kzalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 460         if (halt) {
 461                 halt->msg_type = RNDIS_MSG_HALT;
 462                 halt->msg_len = cpu_to_le32(sizeof *halt);
 463                 (void) rndis_command(dev, (void *)halt, CONTROL_BUFFER_SIZE);
 464                 kfree(halt);
 465         }
 466
 467         usbnet_cdc_unbind(dev, intf);
 468 }
 469 EXPORT_SYMBOL_GPL(rndis_unbind);
 470
 471 /*
 472  * DATA -- host must not write zlps
 473  */
 474 int rndis_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 475 {
 476         /* peripheral may have batched packets to us... */
 477         while (likely(skb->len)) {
 478                 struct rndis_data_hdr   *hdr = (void *)skb->data;
 479                 struct sk_buff          *skb2;
 480                 u32                     msg_len, data_offset, data_len;
 481
 482                 msg_len = le32_to_cpu(hdr->msg_len);
 483                 data_offset = le32_to_cpu(hdr->data_offset);
 484                 data_len = le32_to_cpu(hdr->data_len);
 485
 486                 /* don't choke if we see oob, per-packet data, etc */
 487                 if (unlikely(hdr->msg_type != RNDIS_MSG_PACKET
 488                                 || skb->len < msg_len
 489                                 || (data_offset + data_len + 8) > msg_len)) {
 490                         dev->net->stats.rx_frame_errors++;
 491                         devdbg(dev, "bad rndis message %d/%d/%d/%d, len %d",
 492                                 le32_to_cpu(hdr->msg_type),
 493                                 msg_len, data_offset, data_len, skb->len);
 494                         return 0;
 495                 }
 496                 skb_pull(skb, 8 + data_offset);
 497
 498                 /* at most one packet left? */
 499                 if (likely((data_len - skb->len) <= sizeof *hdr)) {
 500                         skb_trim(skb, data_len);
 501                         break;
 502                 }
 503
 504                 /* try to return all the packets in the batch */
 505                 skb2 = skb_clone(skb, GFP_ATOMIC);
 506                 if (unlikely(!skb2))
 507                         break;
 508                 skb_pull(skb, msg_len - sizeof *hdr);
 509                 skb_trim(skb2, data_len);
 510                 usbnet_skb_return(dev, skb2);
 511         }
 512
 513         /* caller will usbnet_skb_return the remaining packet */
 514         return 1;
 515 }
 516 EXPORT_SYMBOL_GPL(rndis_rx_fixup);
 517
 518 struct sk_buff *
 519 rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 520 {
 521         struct rndis_data_hdr   *hdr;
 522         struct sk_buff          *skb2;
 523         unsigned                len = skb->len;
 524
 525         if (likely(!skb_cloned(skb))) {
 526                 int     room = skb_headroom(skb);
 527
 528                 /* enough head room as-is? */
 529                 if (unlikely((sizeof *hdr) <= room))
 530                         goto fill;
 531
 532                 /* enough room, but needs to be readjusted? */
 533                 room += skb_tailroom(skb);
 534                 if (likely((sizeof *hdr) <= room)) {
 535                         skb->data = memmove(skb->head + sizeof *hdr,
 536                                             skb->data, len);
 537                         skb_set_tail_pointer(skb, len);
 538                         goto fill;
 539                 }
 540         }
 541
 542         /* create a new skb, with the correct size (and tailpad) */
 543         skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
 544         dev_kfree_skb_any(skb);
 545         if (unlikely(!skb2))
 546                 return skb2;
 547         skb = skb2;
 548
 549         /* fill out the RNDIS header.  we won't bother trying to batch
 550          * packets; Linux minimizes wasted bandwidth through tx queues.
 551          */
 552 fill:
 553         hdr = (void *) __skb_push(skb, sizeof *hdr);
 554         memset(hdr, 0, sizeof *hdr);
 555         hdr->msg_type = RNDIS_MSG_PACKET;
 556         hdr->msg_len = cpu_to_le32(skb->len);
 557         hdr->data_offset = cpu_to_le32(sizeof(*hdr) - 8);
 558         hdr->data_len = cpu_to_le32(len);
 559
 560         /* FIXME make the last packet always be short ... */
 561         return skb;
 562 }
 563 EXPORT_SYMBOL_GPL(rndis_tx_fixup);
 564
 565
 566 static const struct driver_info rndis_info = {
 567         .description =  "RNDIS device",
 568         .flags =        FLAG_ETHER | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 569         .bind =         rndis_bind,
 570         .unbind =       rndis_unbind,
 571         .status =       rndis_status,
 572         .rx_fixup =     rndis_rx_fixup,
 573         .tx_fixup =     rndis_tx_fixup,
 574 };
 575
 576 /*-------------------------------------------------------------------------*/
 577
 578 static const struct usb_device_id       products [] = {
 579 {
 580         /* RNDIS is MSFT's un-official variant of CDC ACM */
 581         USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
 582         .driver_info = (unsigned long) &rndis_info,
 583 }, {
 584         /* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
 585         USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
 586         .driver_info = (unsigned long) &rndis_info,
 587 }, {
 588         /* RNDIS for tethering */
 589         USB_INTERFACE_INFO(USB_CLASS_WIRELESS_CONTROLLER, 1, 3),
 590         .driver_info = (unsigned long) &rndis_info,
 591 },
 592         { },            // END
 593 };
 594 MODULE_DEVICE_TABLE(usb, products);
 595
 596 static struct usb_driver rndis_driver = {
 597         .name =         "rndis_host",
 598         .id_table =     products,
 599         .probe =        usbnet_probe,
 600         .disconnect =   usbnet_disconnect,
 601         .suspend =      usbnet_suspend,
 602         .resume =       usbnet_resume,
 603 };
 604
 605 static int __init rndis_init(void)
 606 {
 607         return usb_register(&rndis_driver);
 608 }
 609 module_init(rndis_init);
 610
 611 static void __exit rndis_exit(void)
 612 {
 613         usb_deregister(&rndis_driver);
 614 }
 615 module_exit(rndis_exit);
 616
 617 MODULE_AUTHOR("David Brownell");
 618 MODULE_DESCRIPTION("USB Host side RNDIS driver");
 619 MODULE_LICENSE("GPL");