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/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  */
  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  */
  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  */
 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  */
 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
 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
 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
 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  */
 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 *
 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
 613 static int __init rndis_init(void)
 614 {
 615         return usb_register(&rndis_driver);
 616 }
 617 module_init(rndis_init);
 618
 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");