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         netdev_dbg(dev->net, "rndis status urb, len %d stat %d\n",
  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  * RNDIS indicate messages.
  69  */
  70 static void rndis_msg_indicate(struct usbnet *dev, struct rndis_indicate *msg,
  71                                 int buflen)
  72 {
  73         struct cdc_state *info = (void *)&dev->data;
  74         struct device *udev = &info->control->dev;
  75
  76         if (dev->driver_info->indication) {
  77                 dev->driver_info->indication(dev, msg, buflen);
  78         } else {
  79                 switch (msg->status) {
  80                 case RNDIS_STATUS_MEDIA_CONNECT:
  81                         dev_info(udev, "rndis media connect\n");
  82                         break;
  83                 case RNDIS_STATUS_MEDIA_DISCONNECT:
  84                         dev_info(udev, "rndis media disconnect\n");
  85                         break;
  86                 default:
  87                         dev_info(udev, "rndis indication: 0x%08x\n",
  88                                         le32_to_cpu(msg->status));
  89                 }
  90         }
  91 }
  92
  93 /*
  94  * RPC done RNDIS-style.  Caller guarantees:
  95  * - message is properly byteswapped
  96  * - there's no other request pending
  97  * - buf can hold up to 1KB response (required by RNDIS spec)
  98  * On return, the first few entries are already byteswapped.
  99  *
 100  * Call context is likely probe(), before interface name is known,
 101  * which is why we won't try to use it in the diagnostics.
 102  */
 103 int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf, int buflen)
 104 {
 105         struct cdc_state        *info = (void *) &dev->data;
 106         int                     master_ifnum;
 107         int                     retval;
 108         unsigned                count;
 109         __le32                  rsp;
 110         u32                     xid = 0, msg_len, request_id;
 111
 112         /* REVISIT when this gets called from contexts other than probe() or
 113          * disconnect(): either serialize, or dispatch responses on xid
 114          */
 115
 116         /* Issue the request; xid is unique, don't bother byteswapping it */
 117         if (likely(buf->msg_type != RNDIS_MSG_HALT &&
 118                    buf->msg_type != RNDIS_MSG_RESET)) {
 119                 xid = dev->xid++;
 120                 if (!xid)
 121                         xid = dev->xid++;
 122                 buf->request_id = (__force __le32) xid;
 123         }
 124         master_ifnum = info->control->cur_altsetting->desc.bInterfaceNumber;
 125         retval = usb_control_msg(dev->udev,
 126                 usb_sndctrlpipe(dev->udev, 0),
 127                 USB_CDC_SEND_ENCAPSULATED_COMMAND,
 128                 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 129                 0, master_ifnum,
 130                 buf, le32_to_cpu(buf->msg_len),
 131                 RNDIS_CONTROL_TIMEOUT_MS);
 132         if (unlikely(retval < 0 || xid == 0))
 133                 return retval;
 134
 135         // FIXME Seems like some devices discard responses when
 136         // we time out and cancel our "get response" requests...
 137         // so, this is fragile.  Probably need to poll for status.
 138
 139         /* ignore status endpoint, just poll the control channel;
 140          * the request probably completed immediately
 141          */
 142         rsp = buf->msg_type | RNDIS_MSG_COMPLETION;
 143         for (count = 0; count < 10; count++) {
 144                 memset(buf, 0, CONTROL_BUFFER_SIZE);
 145                 retval = usb_control_msg(dev->udev,
 146                         usb_rcvctrlpipe(dev->udev, 0),
 147                         USB_CDC_GET_ENCAPSULATED_RESPONSE,
 148                         USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 149                         0, master_ifnum,
 150                         buf, buflen,
 151                         RNDIS_CONTROL_TIMEOUT_MS);
 152                 if (likely(retval >= 8)) {
 153                         msg_len = le32_to_cpu(buf->msg_len);
 154                         request_id = (__force u32) buf->request_id;
 155                         if (likely(buf->msg_type == rsp)) {
 156                                 if (likely(request_id == xid)) {
 157                                         if (unlikely(rsp == RNDIS_MSG_RESET_C))
 158                                                 return 0;
 159                                         if (likely(RNDIS_STATUS_SUCCESS
 160                                                         == buf->status))
 161                                                 return 0;
 162                                         dev_dbg(&info->control->dev,
 163                                                 "rndis reply status %08x\n",
 164                                                 le32_to_cpu(buf->status));
 165                                         return -EL3RST;
 166                                 }
 167                                 dev_dbg(&info->control->dev,
 168                                         "rndis reply id %d expected %d\n",
 169                                         request_id, xid);
 170                                 /* then likely retry */
 171                         } else switch (buf->msg_type) {
 172                         case RNDIS_MSG_INDICATE:        /* fault/event */
 173                                 rndis_msg_indicate(dev, (void *)buf, buflen);
 174
 175                                 break;
 176                         case RNDIS_MSG_KEEPALIVE: {     /* ping */
 177                                 struct rndis_keepalive_c *msg = (void *)buf;
 178
 179                                 msg->msg_type = RNDIS_MSG_KEEPALIVE_C;
 180                                 msg->msg_len = cpu_to_le32(sizeof *msg);
 181                                 msg->status = RNDIS_STATUS_SUCCESS;
 182                                 retval = usb_control_msg(dev->udev,
 183                                         usb_sndctrlpipe(dev->udev, 0),
 184                                         USB_CDC_SEND_ENCAPSULATED_COMMAND,
 185                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 186                                         0, master_ifnum,
 187                                         msg, sizeof *msg,
 188                                         RNDIS_CONTROL_TIMEOUT_MS);
 189                                 if (unlikely(retval < 0))
 190                                         dev_dbg(&info->control->dev,
 191                                                 "rndis keepalive err %d\n",
 192                                                 retval);
 193                                 }
 194                                 break;
 195                         default:
 196                                 dev_dbg(&info->control->dev,
 197                                         "unexpected rndis msg %08x len %d\n",
 198                                         le32_to_cpu(buf->msg_type), msg_len);
 199                         }
 200                 } else {
 201                         /* device probably issued a protocol stall; ignore */
 202                         dev_dbg(&info->control->dev,
 203                                 "rndis response error, code %d\n", retval);
 204                 }
 205                 msleep(20);
 206         }
 207         dev_dbg(&info->control->dev, "rndis response timeout\n");
 208         return -ETIMEDOUT;
 209 }
 210 EXPORT_SYMBOL_GPL(rndis_command);
 211
 212 /*
 213  * rndis_query:
 214  *
 215  * Performs a query for @oid along with 0 or more bytes of payload as
 216  * specified by @in_len. If @reply_len is not set to -1 then the reply
 217  * length is checked against this value, resulting in an error if it
 218  * doesn't match.
 219  *
 220  * NOTE: Adding a payload exactly or greater than the size of the expected
 221  * response payload is an evident requirement MSFT added for ActiveSync.
 222  *
 223  * The only exception is for OIDs that return a variably sized response,
 224  * in which case no payload should be added.  This undocumented (and
 225  * nonsensical!) issue was found by sniffing protocol requests from the
 226  * ActiveSync 4.1 Windows driver.
 227  */
 228 static int rndis_query(struct usbnet *dev, struct usb_interface *intf,
 229                 void *buf, __le32 oid, u32 in_len,
 230                 void **reply, int *reply_len)
 231 {
 232         int retval;
 233         union {
 234                 void                    *buf;
 235                 struct rndis_msg_hdr    *header;
 236                 struct rndis_query      *get;
 237                 struct rndis_query_c    *get_c;
 238         } u;
 239         u32 off, len;
 240
 241         u.buf = buf;
 242
 243         memset(u.get, 0, sizeof *u.get + in_len);
 244         u.get->msg_type = RNDIS_MSG_QUERY;
 245         u.get->msg_len = cpu_to_le32(sizeof *u.get + in_len);
 246         u.get->oid = oid;
 247         u.get->len = cpu_to_le32(in_len);
 248         u.get->offset = cpu_to_le32(20);
 249
 250         retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 251         if (unlikely(retval < 0)) {
 252                 dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) failed, %d\n",
 253                                 oid, retval);
 254                 return retval;
 255         }
 256
 257         off = le32_to_cpu(u.get_c->offset);
 258         len = le32_to_cpu(u.get_c->len);
 259         if (unlikely((8 + off + len) > CONTROL_BUFFER_SIZE))
 260                 goto response_error;
 261
 262         if (*reply_len != -1 && len != *reply_len)
 263                 goto response_error;
 264
 265         *reply = (unsigned char *) &u.get_c->request_id + off;
 266         *reply_len = len;
 267
 268         return retval;
 269
 270 response_error:
 271         dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) "
 272                         "invalid response - off %d len %d\n",
 273                 oid, off, len);
 274         return -EDOM;
 275 }
 276
 277 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,29))
 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 #endif
 288
 289 int
 290 generic_rndis_bind(struct usbnet *dev, struct usb_interface *intf, int flags)
 291 {
 292         int                     retval;
 293         struct net_device       *net = dev->net;
 294         struct cdc_state        *info = (void *) &dev->data;
 295         union {
 296                 void                    *buf;
 297                 struct rndis_msg_hdr    *header;
 298                 struct rndis_init       *init;
 299                 struct rndis_init_c     *init_c;
 300                 struct rndis_query      *get;
 301                 struct rndis_query_c    *get_c;
 302                 struct rndis_set        *set;
 303                 struct rndis_set_c      *set_c;
 304                 struct rndis_halt       *halt;
 305         } u;
 306         u32                     tmp;
 307         __le32                  phym_unspec, *phym;
 308         int                     reply_len;
 309         unsigned char           *bp;
 310
 311         /* we can't rely on i/o from stack working, or stack allocation */
 312         u.buf = kmalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 313         if (!u.buf)
 314                 return -ENOMEM;
 315         retval = usbnet_generic_cdc_bind(dev, intf);
 316         if (retval < 0)
 317                 goto fail;
 318
 319         u.init->msg_type = RNDIS_MSG_INIT;
 320         u.init->msg_len = cpu_to_le32(sizeof *u.init);
 321         u.init->major_version = cpu_to_le32(1);
 322         u.init->minor_version = cpu_to_le32(0);
 323
 324         /* max transfer (in spec) is 0x4000 at full speed, but for
 325          * TX we'll stick to one Ethernet packet plus RNDIS framing.
 326          * For RX we handle drivers that zero-pad to end-of-packet.
 327          * Don't let userspace change these settings.
 328          *
 329          * NOTE: there still seems to be wierdness here, as if we need
 330          * to do some more things to make sure WinCE targets accept this.
 331          * They default to jumbograms of 8KB or 16KB, which is absurd
 332          * for such low data rates and which is also more than Linux
 333          * can usually expect to allocate for SKB data...
 334          */
 335         net->hard_header_len += sizeof (struct rndis_data_hdr);
 336         dev->hard_mtu = net->mtu + net->hard_header_len;
 337
 338         dev->maxpacket = usb_maxpacket(dev->udev, dev->out, 1);
 339         if (dev->maxpacket == 0) {
 340                 netif_dbg(dev, probe, dev->net,
 341                           "dev->maxpacket can't be 0\n");
 342                 retval = -EINVAL;
 343                 goto fail_and_release;
 344         }
 345
 346         dev->rx_urb_size = dev->hard_mtu + (dev->maxpacket + 1);
 347         dev->rx_urb_size &= ~(dev->maxpacket - 1);
 348         u.init->max_transfer_size = cpu_to_le32(dev->rx_urb_size);
 349
 350 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,29))
 351         net->netdev_ops = &rndis_netdev_ops;
 352 #else
 353         net->change_mtu = NULL;
 354 #endif
 355
 356         retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 357         if (unlikely(retval < 0)) {
 358                 /* it might not even be an RNDIS device!! */
 359                 dev_err(&intf->dev, "RNDIS init failed, %d\n", retval);
 360                 goto fail_and_release;
 361         }
 362         tmp = le32_to_cpu(u.init_c->max_transfer_size);
 363         if (tmp < dev->hard_mtu) {
 364                 if (tmp <= net->hard_header_len) {
 365                         dev_err(&intf->dev,
 366                                 "dev can't take %u byte packets (max %u)\n",
 367                                 dev->hard_mtu, tmp);
 368                         retval = -EINVAL;
 369                         goto halt_fail_and_release;
 370                 }
 371                 dev_warn(&intf->dev,
 372                          "dev can't take %u byte packets (max %u), "
 373                          "adjusting MTU to %u\n",
 374                          dev->hard_mtu, tmp, tmp - net->hard_header_len);
 375                 dev->hard_mtu = tmp;
 376                 net->mtu = dev->hard_mtu - net->hard_header_len;
 377         }
 378
 379         /* REVISIT:  peripheral "alignment" request is ignored ... */
 380         dev_dbg(&intf->dev,
 381                 "hard mtu %u (%u from dev), rx buflen %Zu, align %d\n",
 382                 dev->hard_mtu, tmp, dev->rx_urb_size,
 383                 1 << le32_to_cpu(u.init_c->packet_alignment));
 384
 385         /* module has some device initialization code needs to be done right
 386          * after RNDIS_INIT */
 387         if (dev->driver_info->early_init &&
 388                         dev->driver_info->early_init(dev) != 0)
 389                 goto halt_fail_and_release;
 390
 391         /* Check physical medium */
 392         phym = NULL;
 393         reply_len = sizeof *phym;
 394         retval = rndis_query(dev, intf, u.buf, OID_GEN_PHYSICAL_MEDIUM,
 395                         0, (void **) &phym, &reply_len);
 396         if (retval != 0 || !phym) {
 397                 /* OID is optional so don't fail here. */
 398                 phym_unspec = RNDIS_PHYSICAL_MEDIUM_UNSPECIFIED;
 399                 phym = &phym_unspec;
 400         }
 401         if ((flags & FLAG_RNDIS_PHYM_WIRELESS) &&
 402                         *phym != RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
 403                 netif_dbg(dev, probe, dev->net,
 404                           "driver requires wireless physical medium, but device is not\n");
 405                 retval = -ENODEV;
 406                 goto halt_fail_and_release;
 407         }
 408         if ((flags & FLAG_RNDIS_PHYM_NOT_WIRELESS) &&
 409                         *phym == RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
 410                 netif_dbg(dev, probe, dev->net,
 411                           "driver requires non-wireless physical medium, but device is wireless.\n");
 412                 retval = -ENODEV;
 413                 goto halt_fail_and_release;
 414         }
 415
 416         /* Get designated host ethernet address */
 417         reply_len = ETH_ALEN;
 418         retval = rndis_query(dev, intf, u.buf, OID_802_3_PERMANENT_ADDRESS,
 419                         48, (void **) &bp, &reply_len);
 420         if (unlikely(retval< 0)) {
 421                 dev_err(&intf->dev, "rndis get ethaddr, %d\n", retval);
 422                 goto halt_fail_and_release;
 423         }
 424         memcpy(net->dev_addr, bp, ETH_ALEN);
 425         memcpy(net->perm_addr, bp, ETH_ALEN);
 426
 427         /* set a nonzero filter to enable data transfers */
 428         memset(u.set, 0, sizeof *u.set);
 429         u.set->msg_type = RNDIS_MSG_SET;
 430         u.set->msg_len = cpu_to_le32(4 + sizeof *u.set);
 431         u.set->oid = OID_GEN_CURRENT_PACKET_FILTER;
 432         u.set->len = cpu_to_le32(4);
 433         u.set->offset = cpu_to_le32((sizeof *u.set) - 8);
 434         *(__le32 *)(u.buf + sizeof *u.set) = RNDIS_DEFAULT_FILTER;
 435
 436         retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 437         if (unlikely(retval < 0)) {
 438                 dev_err(&intf->dev, "rndis set packet filter, %d\n", retval);
 439                 goto halt_fail_and_release;
 440         }
 441
 442         retval = 0;
 443
 444         kfree(u.buf);
 445         return retval;
 446
 447 halt_fail_and_release:
 448         memset(u.halt, 0, sizeof *u.halt);
 449         u.halt->msg_type = RNDIS_MSG_HALT;
 450         u.halt->msg_len = cpu_to_le32(sizeof *u.halt);
 451         (void) rndis_command(dev, (void *)u.halt, CONTROL_BUFFER_SIZE);
 452 fail_and_release:
 453         usb_set_intfdata(info->data, NULL);
 454         usb_driver_release_interface(driver_of(intf), info->data);
 455         info->data = NULL;
 456 fail:
 457         kfree(u.buf);
 458         return retval;
 459 }
 460 EXPORT_SYMBOL_GPL(generic_rndis_bind);
 461
 462 static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
 463 {
 464         return generic_rndis_bind(dev, intf, FLAG_RNDIS_PHYM_NOT_WIRELESS);
 465 }
 466
 467 void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
 468 {
 469         struct rndis_halt       *halt;
 470
 471         /* try to clear any rndis state/activity (no i/o from stack!) */
 472         halt = kzalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 473         if (halt) {
 474                 halt->msg_type = RNDIS_MSG_HALT;
 475                 halt->msg_len = cpu_to_le32(sizeof *halt);
 476                 (void) rndis_command(dev, (void *)halt, CONTROL_BUFFER_SIZE);
 477                 kfree(halt);
 478         }
 479
 480         usbnet_cdc_unbind(dev, intf);
 481 }
 482 EXPORT_SYMBOL_GPL(rndis_unbind);
 483
 484 /*
 485  * DATA -- host must not write zlps
 486  */
 487 int rndis_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 488 {
 489         /* peripheral may have batched packets to us... */
 490         while (likely(skb->len)) {
 491                 struct rndis_data_hdr   *hdr = (void *)skb->data;
 492                 struct sk_buff          *skb2;
 493                 u32                     msg_len, data_offset, data_len;
 494
 495                 msg_len = le32_to_cpu(hdr->msg_len);
 496                 data_offset = le32_to_cpu(hdr->data_offset);
 497                 data_len = le32_to_cpu(hdr->data_len);
 498
 499                 /* don't choke if we see oob, per-packet data, etc */
 500                 if (unlikely(hdr->msg_type != RNDIS_MSG_PACKET ||
 501                              skb->len < msg_len ||
 502                              (data_offset + data_len + 8) > msg_len)) {
 503                         dev->net->stats.rx_frame_errors++;
 504                         netdev_dbg(dev->net, "bad rndis message %d/%d/%d/%d, len %d\n",
 505                                    le32_to_cpu(hdr->msg_type),
 506                                    msg_len, data_offset, data_len, skb->len);
 507                         return 0;
 508                 }
 509                 skb_pull(skb, 8 + data_offset);
 510
 511                 /* at most one packet left? */
 512                 if (likely((data_len - skb->len) <= sizeof *hdr)) {
 513                         skb_trim(skb, data_len);
 514                         break;
 515                 }
 516
 517                 /* try to return all the packets in the batch */
 518                 skb2 = skb_clone(skb, GFP_ATOMIC);
 519                 if (unlikely(!skb2))
 520                         break;
 521                 skb_pull(skb, msg_len - sizeof *hdr);
 522                 skb_trim(skb2, data_len);
 523                 usbnet_skb_return(dev, skb2);
 524         }
 525
 526         /* caller will usbnet_skb_return the remaining packet */
 527         return 1;
 528 }
 529 EXPORT_SYMBOL_GPL(rndis_rx_fixup);
 530
 531 struct sk_buff *
 532 rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 533 {
 534         struct rndis_data_hdr   *hdr;
 535         struct sk_buff          *skb2;
 536         unsigned                len = skb->len;
 537
 538         if (likely(!skb_cloned(skb))) {
 539                 int     room = skb_headroom(skb);
 540
 541                 /* enough head room as-is? */
 542                 if (unlikely((sizeof *hdr) <= room))
 543                         goto fill;
 544
 545                 /* enough room, but needs to be readjusted? */
 546                 room += skb_tailroom(skb);
 547                 if (likely((sizeof *hdr) <= room)) {
 548                         skb->data = memmove(skb->head + sizeof *hdr,
 549                                             skb->data, len);
 550                         skb_set_tail_pointer(skb, len);
 551                         goto fill;
 552                 }
 553         }
 554
 555         /* create a new skb, with the correct size (and tailpad) */
 556         skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
 557         dev_kfree_skb_any(skb);
 558         if (unlikely(!skb2))
 559                 return skb2;
 560         skb = skb2;
 561
 562         /* fill out the RNDIS header.  we won't bother trying to batch
 563          * packets; Linux minimizes wasted bandwidth through tx queues.
 564          */
 565 fill:
 566         hdr = (void *) __skb_push(skb, sizeof *hdr);
 567         memset(hdr, 0, sizeof *hdr);
 568         hdr->msg_type = RNDIS_MSG_PACKET;
 569         hdr->msg_len = cpu_to_le32(skb->len);
 570         hdr->data_offset = cpu_to_le32(sizeof(*hdr) - 8);
 571         hdr->data_len = cpu_to_le32(len);
 572
 573         /* FIXME make the last packet always be short ... */
 574         return skb;
 575 }
 576 EXPORT_SYMBOL_GPL(rndis_tx_fixup);
 577
 578
 579 static const struct driver_info rndis_info = {
 580         .description =  "RNDIS device",
 581         .flags =        FLAG_ETHER | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 582         .bind =         rndis_bind,
 583         .unbind =       rndis_unbind,
 584         .status =       rndis_status,
 585         .rx_fixup =     rndis_rx_fixup,
 586         .tx_fixup =     rndis_tx_fixup,
 587 };
 588
 589 /*-------------------------------------------------------------------------*/
 590
 591 static const struct usb_device_id       products [] = {
 592 {
 593         /* RNDIS is MSFT's un-official variant of CDC ACM */
 594         USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
 595         .driver_info = (unsigned long) &rndis_info,
 596 }, {
 597         /* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
 598         USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
 599         .driver_info = (unsigned long) &rndis_info,
 600 }, {
 601         /* RNDIS for tethering */
 602         USB_INTERFACE_INFO(USB_CLASS_WIRELESS_CONTROLLER, 1, 3),
 603         .driver_info = (unsigned long) &rndis_info,
 604 },
 605         { },            // END
 606 };
 607 MODULE_DEVICE_TABLE(usb, products);
 608
 609 static struct usb_driver rndis_driver = {
 610         .name =         "rndis_host",
 611         .id_table =     products,
 612         .probe =        usbnet_probe,
 613         .disconnect =   usbnet_disconnect,
 614         .suspend =      usbnet_suspend,
 615         .resume =       usbnet_resume,
 616 };
 617
 618 static int __init rndis_init(void)
 619 {
 620         return usb_register(&rndis_driver);
 621 }
 622 module_init(rndis_init);
 623
 624 static void __exit rndis_exit(void)
 625 {
 626         usb_deregister(&rndis_driver);
 627 }
 628 module_exit(rndis_exit);
 629
 630 MODULE_AUTHOR("David Brownell");
 631 MODULE_DESCRIPTION("USB Host side RNDIS driver");
 632 MODULE_LICENSE("GPL");