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, see <http://www.gnu.org/licenses/>.
  17  */
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/netdevice.h>
  21 #include <linux/etherdevice.h>
  22 #include <linux/ethtool.h>
  23 #include <linux/workqueue.h>
  24 #include <linux/slab.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                 u32 status = le32_to_cpu(msg->status);
  80
  81                 switch (status) {
  82                 case RNDIS_STATUS_MEDIA_CONNECT:
  83                         dev_info(udev, "rndis media connect\n");
  84                         break;
  85                 case RNDIS_STATUS_MEDIA_DISCONNECT:
  86                         dev_info(udev, "rndis media disconnect\n");
  87                         break;
  88                 default:
  89                         dev_info(udev, "rndis indication: 0x%08x\n", 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         struct usb_cdc_notification notification;
 108         int                     master_ifnum;
 109         int                     retval;
 110         int                     partial;
 111         unsigned                count;
 112         u32                     xid = 0, msg_len, request_id, msg_type, rsp,
 113                                 status;
 114
 115         /* REVISIT when this gets called from contexts other than probe() or
 116          * disconnect(): either serialize, or dispatch responses on xid
 117          */
 118
 119         msg_type = le32_to_cpu(buf->msg_type);
 120
 121         /* Issue the request; xid is unique, don't bother byteswapping it */
 122         if (likely(msg_type != RNDIS_MSG_HALT && msg_type != RNDIS_MSG_RESET)) {
 123                 xid = dev->xid++;
 124                 if (!xid)
 125                         xid = dev->xid++;
 126                 buf->request_id = (__force __le32) xid;
 127         }
 128         master_ifnum = info->control->cur_altsetting->desc.bInterfaceNumber;
 129         retval = usb_control_msg(dev->udev,
 130                 usb_sndctrlpipe(dev->udev, 0),
 131                 USB_CDC_SEND_ENCAPSULATED_COMMAND,
 132                 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 133                 0, master_ifnum,
 134                 buf, le32_to_cpu(buf->msg_len),
 135                 RNDIS_CONTROL_TIMEOUT_MS);
 136         if (unlikely(retval < 0 || xid == 0))
 137                 return retval;
 138
 139         /* Some devices don't respond on the control channel until
 140          * polled on the status channel, so do that first. */
 141         if (dev->driver_info->data & RNDIS_DRIVER_DATA_POLL_STATUS) {
 142                 retval = usb_interrupt_msg(
 143                         dev->udev,
 144                         usb_rcvintpipe(dev->udev,
 145                                        dev->status->desc.bEndpointAddress),
 146                         &notification, sizeof(notification), &partial,
 147                         RNDIS_CONTROL_TIMEOUT_MS);
 148                 if (unlikely(retval < 0))
 149                         return retval;
 150         }
 151
 152         /* Poll the control channel; the request probably completed immediately */
 153         rsp = le32_to_cpu(buf->msg_type) | RNDIS_MSG_COMPLETION;
 154         for (count = 0; count < 10; count++) {
 155                 memset(buf, 0, CONTROL_BUFFER_SIZE);
 156                 retval = usb_control_msg(dev->udev,
 157                         usb_rcvctrlpipe(dev->udev, 0),
 158                         USB_CDC_GET_ENCAPSULATED_RESPONSE,
 159                         USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 160                         0, master_ifnum,
 161                         buf, buflen,
 162                         RNDIS_CONTROL_TIMEOUT_MS);
 163                 if (likely(retval >= 8)) {
 164                         msg_type = le32_to_cpu(buf->msg_type);
 165                         msg_len = le32_to_cpu(buf->msg_len);
 166                         status = le32_to_cpu(buf->status);
 167                         request_id = (__force u32) buf->request_id;
 168                         if (likely(msg_type == rsp)) {
 169                                 if (likely(request_id == xid)) {
 170                                         if (unlikely(rsp == RNDIS_MSG_RESET_C))
 171                                                 return 0;
 172                                         if (likely(RNDIS_STATUS_SUCCESS ==
 173                                                         status))
 174                                                 return 0;
 175                                         dev_dbg(&info->control->dev,
 176                                                 "rndis reply status %08x\n",
 177                                                 status);
 178                                         return -EL3RST;
 179                                 }
 180                                 dev_dbg(&info->control->dev,
 181                                         "rndis reply id %d expected %d\n",
 182                                         request_id, xid);
 183                                 /* then likely retry */
 184                         } else switch (msg_type) {
 185                         case RNDIS_MSG_INDICATE: /* fault/event */
 186                                 rndis_msg_indicate(dev, (void *)buf, buflen);
 187                                 break;
 188                         case RNDIS_MSG_KEEPALIVE: { /* ping */
 189                                 struct rndis_keepalive_c *msg = (void *)buf;
 190
 191                                 msg->msg_type = cpu_to_le32(RNDIS_MSG_KEEPALIVE_C);
 192                                 msg->msg_len = cpu_to_le32(sizeof *msg);
 193                                 msg->status = cpu_to_le32(RNDIS_STATUS_SUCCESS);
 194                                 retval = usb_control_msg(dev->udev,
 195                                         usb_sndctrlpipe(dev->udev, 0),
 196                                         USB_CDC_SEND_ENCAPSULATED_COMMAND,
 197                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 198                                         0, master_ifnum,
 199                                         msg, sizeof *msg,
 200                                         RNDIS_CONTROL_TIMEOUT_MS);
 201                                 if (unlikely(retval < 0))
 202                                         dev_dbg(&info->control->dev,
 203                                                 "rndis keepalive err %d\n",
 204                                                 retval);
 205                                 }
 206                                 break;
 207                         default:
 208                                 dev_dbg(&info->control->dev,
 209                                         "unexpected rndis msg %08x len %d\n",
 210                                         le32_to_cpu(buf->msg_type), msg_len);
 211                         }
 212                 } else {
 213                         /* device probably issued a protocol stall; ignore */
 214                         dev_dbg(&info->control->dev,
 215                                 "rndis response error, code %d\n", retval);
 216                 }
 217                 msleep(20);
 218         }
 219         dev_dbg(&info->control->dev, "rndis response timeout\n");
 220         return -ETIMEDOUT;
 221 }
 222 EXPORT_SYMBOL_GPL(rndis_command);
 223
 224 /*
 225  * rndis_query:
 226  *
 227  * Performs a query for @oid along with 0 or more bytes of payload as
 228  * specified by @in_len. If @reply_len is not set to -1 then the reply
 229  * length is checked against this value, resulting in an error if it
 230  * doesn't match.
 231  *
 232  * NOTE: Adding a payload exactly or greater than the size of the expected
 233  * response payload is an evident requirement MSFT added for ActiveSync.
 234  *
 235  * The only exception is for OIDs that return a variably sized response,
 236  * in which case no payload should be added.  This undocumented (and
 237  * nonsensical!) issue was found by sniffing protocol requests from the
 238  * ActiveSync 4.1 Windows driver.
 239  */
 240 static int rndis_query(struct usbnet *dev, struct usb_interface *intf,
 241                 void *buf, u32 oid, u32 in_len,
 242                 void **reply, int *reply_len)
 243 {
 244         int retval;
 245         union {
 246                 void                    *buf;
 247                 struct rndis_msg_hdr    *header;
 248                 struct rndis_query      *get;
 249                 struct rndis_query_c    *get_c;
 250         } u;
 251         u32 off, len;
 252
 253         u.buf = buf;
 254
 255         memset(u.get, 0, sizeof *u.get + in_len);
 256         u.get->msg_type = cpu_to_le32(RNDIS_MSG_QUERY);
 257         u.get->msg_len = cpu_to_le32(sizeof *u.get + in_len);
 258         u.get->oid = cpu_to_le32(oid);
 259         u.get->len = cpu_to_le32(in_len);
 260         u.get->offset = cpu_to_le32(20);
 261
 262         retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 263         if (unlikely(retval < 0)) {
 264                 dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) failed, %d\n",
 265                                 oid, retval);
 266                 return retval;
 267         }
 268
 269         off = le32_to_cpu(u.get_c->offset);
 270         len = le32_to_cpu(u.get_c->len);
 271         if (unlikely((8 + off + len) > CONTROL_BUFFER_SIZE))
 272                 goto response_error;
 273
 274         if (*reply_len != -1 && len != *reply_len)
 275                 goto response_error;
 276
 277         *reply = (unsigned char *) &u.get_c->request_id + off;
 278         *reply_len = len;
 279
 280         return retval;
 281
 282 response_error:
 283         dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) "
 284                         "invalid response - off %d len %d\n",
 285                 oid, off, len);
 286         return -EDOM;
 287 }
 288
 289 /* same as usbnet_netdev_ops but MTU change not allowed */
 290 static const struct net_device_ops rndis_netdev_ops = {
 291         .ndo_open               = usbnet_open,
 292         .ndo_stop               = usbnet_stop,
 293         .ndo_start_xmit         = usbnet_start_xmit,
 294         .ndo_tx_timeout         = usbnet_tx_timeout,
 295         .ndo_set_mac_address    = eth_mac_addr,
 296         .ndo_validate_addr      = eth_validate_addr,
 297 };
 298
 299 int
 300 generic_rndis_bind(struct usbnet *dev, struct usb_interface *intf, int flags)
 301 {
 302         int                     retval;
 303         struct net_device       *net = dev->net;
 304         struct cdc_state        *info = (void *) &dev->data;
 305         union {
 306                 void                    *buf;
 307                 struct rndis_msg_hdr    *header;
 308                 struct rndis_init       *init;
 309                 struct rndis_init_c     *init_c;
 310                 struct rndis_query      *get;
 311                 struct rndis_query_c    *get_c;
 312                 struct rndis_set        *set;
 313                 struct rndis_set_c      *set_c;
 314                 struct rndis_halt       *halt;
 315         } u;
 316         u32                     tmp;
 317         __le32                  phym_unspec, *phym;
 318         int                     reply_len;
 319         unsigned char           *bp;
 320
 321         /* we can't rely on i/o from stack working, or stack allocation */
 322         u.buf = kmalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 323         if (!u.buf)
 324                 return -ENOMEM;
 325         retval = usbnet_generic_cdc_bind(dev, intf);
 326         if (retval < 0)
 327                 goto fail;
 328
 329         u.init->msg_type = cpu_to_le32(RNDIS_MSG_INIT);
 330         u.init->msg_len = cpu_to_le32(sizeof *u.init);
 331         u.init->major_version = cpu_to_le32(1);
 332         u.init->minor_version = cpu_to_le32(0);
 333
 334         /* max transfer (in spec) is 0x4000 at full speed, but for
 335          * TX we'll stick to one Ethernet packet plus RNDIS framing.
 336          * For RX we handle drivers that zero-pad to end-of-packet.
 337          * Don't let userspace change these settings.
 338          *
 339          * NOTE: there still seems to be wierdness here, as if we need
 340          * to do some more things to make sure WinCE targets accept this.
 341          * They default to jumbograms of 8KB or 16KB, which is absurd
 342          * for such low data rates and which is also more than Linux
 343          * can usually expect to allocate for SKB data...
 344          */
 345         net->hard_header_len += sizeof (struct rndis_data_hdr);
 346         dev->hard_mtu = net->mtu + net->hard_header_len;
 347
 348         dev->maxpacket = usb_maxpacket(dev->udev, dev->out, 1);
 349         if (dev->maxpacket == 0) {
 350                 netif_dbg(dev, probe, dev->net,
 351                           "dev->maxpacket can't be 0\n");
 352                 retval = -EINVAL;
 353                 goto fail_and_release;
 354         }
 355
 356         dev->rx_urb_size = dev->hard_mtu + (dev->maxpacket + 1);
 357         dev->rx_urb_size &= ~(dev->maxpacket - 1);
 358         u.init->max_transfer_size = cpu_to_le32(dev->rx_urb_size);
 359
 360         net->netdev_ops = &rndis_netdev_ops;
 361
 362         retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 363         if (unlikely(retval < 0)) {
 364                 /* it might not even be an RNDIS device!! */
 365                 dev_err(&intf->dev, "RNDIS init failed, %d\n", retval);
 366                 goto fail_and_release;
 367         }
 368         tmp = le32_to_cpu(u.init_c->max_transfer_size);
 369         if (tmp < dev->hard_mtu) {
 370                 if (tmp <= net->hard_header_len) {
 371                         dev_err(&intf->dev,
 372                                 "dev can't take %u byte packets (max %u)\n",
 373                                 dev->hard_mtu, tmp);
 374                         retval = -EINVAL;
 375                         goto halt_fail_and_release;
 376                 }
 377                 dev_warn(&intf->dev,
 378                          "dev can't take %u byte packets (max %u), "
 379                          "adjusting MTU to %u\n",
 380                          dev->hard_mtu, tmp, tmp - net->hard_header_len);
 381                 dev->hard_mtu = tmp;
 382                 net->mtu = dev->hard_mtu - net->hard_header_len;
 383         }
 384
 385         /* REVISIT:  peripheral "alignment" request is ignored ... */
 386         dev_dbg(&intf->dev,
 387                 "hard mtu %u (%u from dev), rx buflen %Zu, align %d\n",
 388                 dev->hard_mtu, tmp, dev->rx_urb_size,
 389                 1 << le32_to_cpu(u.init_c->packet_alignment));
 390
 391         /* module has some device initialization code needs to be done right
 392          * after RNDIS_INIT */
 393         if (dev->driver_info->early_init &&
 394                         dev->driver_info->early_init(dev) != 0)
 395                 goto halt_fail_and_release;
 396
 397         /* Check physical medium */
 398         phym = NULL;
 399         reply_len = sizeof *phym;
 400         retval = rndis_query(dev, intf, u.buf,
 401                              RNDIS_OID_GEN_PHYSICAL_MEDIUM,
 402                              0, (void **) &phym, &reply_len);
 403         if (retval != 0 || !phym) {
 404                 /* OID is optional so don't fail here. */
 405                 phym_unspec = cpu_to_le32(RNDIS_PHYSICAL_MEDIUM_UNSPECIFIED);
 406                 phym = &phym_unspec;
 407         }
 408         if ((flags & FLAG_RNDIS_PHYM_WIRELESS) &&
 409             le32_to_cpup(phym) != RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
 410                 netif_dbg(dev, probe, dev->net,
 411                           "driver requires wireless physical medium, but device is not\n");
 412                 retval = -ENODEV;
 413                 goto halt_fail_and_release;
 414         }
 415         if ((flags & FLAG_RNDIS_PHYM_NOT_WIRELESS) &&
 416             le32_to_cpup(phym) == RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
 417                 netif_dbg(dev, probe, dev->net,
 418                           "driver requires non-wireless physical medium, but device is wireless.\n");
 419                 retval = -ENODEV;
 420                 goto halt_fail_and_release;
 421         }
 422
 423         /* Get designated host ethernet address */
 424         reply_len = ETH_ALEN;
 425         retval = rndis_query(dev, intf, u.buf,
 426                              RNDIS_OID_802_3_PERMANENT_ADDRESS,
 427                              48, (void **) &bp, &reply_len);
 428         if (unlikely(retval< 0)) {
 429                 dev_err(&intf->dev, "rndis get ethaddr, %d\n", retval);
 430                 goto halt_fail_and_release;
 431         }
 432         memcpy(net->dev_addr, bp, ETH_ALEN);
 433
 434         /* set a nonzero filter to enable data transfers */
 435         memset(u.set, 0, sizeof *u.set);
 436         u.set->msg_type = cpu_to_le32(RNDIS_MSG_SET);
 437         u.set->msg_len = cpu_to_le32(4 + sizeof *u.set);
 438         u.set->oid = cpu_to_le32(RNDIS_OID_GEN_CURRENT_PACKET_FILTER);
 439         u.set->len = cpu_to_le32(4);
 440         u.set->offset = cpu_to_le32((sizeof *u.set) - 8);
 441         *(__le32 *)(u.buf + sizeof *u.set) = cpu_to_le32(RNDIS_DEFAULT_FILTER);
 442
 443         retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 444         if (unlikely(retval < 0)) {
 445                 dev_err(&intf->dev, "rndis set packet filter, %d\n", retval);
 446                 goto halt_fail_and_release;
 447         }
 448
 449         retval = 0;
 450
 451         kfree(u.buf);
 452         return retval;
 453
 454 halt_fail_and_release:
 455         memset(u.halt, 0, sizeof *u.halt);
 456         u.halt->msg_type = cpu_to_le32(RNDIS_MSG_HALT);
 457         u.halt->msg_len = cpu_to_le32(sizeof *u.halt);
 458         (void) rndis_command(dev, (void *)u.halt, CONTROL_BUFFER_SIZE);
 459 fail_and_release:
 460         usb_set_intfdata(info->data, NULL);
 461         usb_driver_release_interface(driver_of(intf), info->data);
 462         info->data = NULL;
 463 fail:
 464         kfree(u.buf);
 465         return retval;
 466 }
 467 EXPORT_SYMBOL_GPL(generic_rndis_bind);
 468
 469 static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
 470 {
 471         return generic_rndis_bind(dev, intf, FLAG_RNDIS_PHYM_NOT_WIRELESS);
 472 }
 473
 474 void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
 475 {
 476         struct rndis_halt       *halt;
 477
 478         /* try to clear any rndis state/activity (no i/o from stack!) */
 479         halt = kzalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 480         if (halt) {
 481                 halt->msg_type = cpu_to_le32(RNDIS_MSG_HALT);
 482                 halt->msg_len = cpu_to_le32(sizeof *halt);
 483                 (void) rndis_command(dev, (void *)halt, CONTROL_BUFFER_SIZE);
 484                 kfree(halt);
 485         }
 486
 487         usbnet_cdc_unbind(dev, intf);
 488 }
 489 EXPORT_SYMBOL_GPL(rndis_unbind);
 490
 491 /*
 492  * DATA -- host must not write zlps
 493  */
 494 int rndis_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 495 {
 496         /* peripheral may have batched packets to us... */
 497         while (likely(skb->len)) {
 498                 struct rndis_data_hdr   *hdr = (void *)skb->data;
 499                 struct sk_buff          *skb2;
 500                 u32                     msg_type, msg_len, data_offset, data_len;
 501
 502                 msg_type = le32_to_cpu(hdr->msg_type);
 503                 msg_len = le32_to_cpu(hdr->msg_len);
 504                 data_offset = le32_to_cpu(hdr->data_offset);
 505                 data_len = le32_to_cpu(hdr->data_len);
 506
 507                 /* don't choke if we see oob, per-packet data, etc */
 508                 if (unlikely(msg_type != RNDIS_MSG_PACKET || skb->len < msg_len
 509                                 || (data_offset + data_len + 8) > msg_len)) {
 510                         dev->net->stats.rx_frame_errors++;
 511                         netdev_dbg(dev->net, "bad rndis message %d/%d/%d/%d, len %d\n",
 512                                    le32_to_cpu(hdr->msg_type),
 513                                    msg_len, data_offset, data_len, skb->len);
 514                         return 0;
 515                 }
 516                 skb_pull(skb, 8 + data_offset);
 517
 518                 /* at most one packet left? */
 519                 if (likely((data_len - skb->len) <= sizeof *hdr)) {
 520                         skb_trim(skb, data_len);
 521                         break;
 522                 }
 523
 524                 /* try to return all the packets in the batch */
 525                 skb2 = skb_clone(skb, GFP_ATOMIC);
 526                 if (unlikely(!skb2))
 527                         break;
 528                 skb_pull(skb, msg_len - sizeof *hdr);
 529                 skb_trim(skb2, data_len);
 530                 usbnet_skb_return(dev, skb2);
 531         }
 532
 533         /* caller will usbnet_skb_return the remaining packet */
 534         return 1;
 535 }
 536 EXPORT_SYMBOL_GPL(rndis_rx_fixup);
 537
 538 struct sk_buff *
 539 rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 540 {
 541         struct rndis_data_hdr   *hdr;
 542         struct sk_buff          *skb2;
 543         unsigned                len = skb->len;
 544
 545         if (likely(!skb_cloned(skb))) {
 546                 int     room = skb_headroom(skb);
 547
 548                 /* enough head room as-is? */
 549                 if (unlikely((sizeof *hdr) <= room))
 550                         goto fill;
 551
 552                 /* enough room, but needs to be readjusted? */
 553                 room += skb_tailroom(skb);
 554                 if (likely((sizeof *hdr) <= room)) {
 555                         skb->data = memmove(skb->head + sizeof *hdr,
 556                                             skb->data, len);
 557                         skb_set_tail_pointer(skb, len);
 558                         goto fill;
 559                 }
 560         }
 561
 562         /* create a new skb, with the correct size (and tailpad) */
 563         skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
 564         dev_kfree_skb_any(skb);
 565         if (unlikely(!skb2))
 566                 return skb2;
 567         skb = skb2;
 568
 569         /* fill out the RNDIS header.  we won't bother trying to batch
 570          * packets; Linux minimizes wasted bandwidth through tx queues.
 571          */
 572 fill:
 573         hdr = (void *) __skb_push(skb, sizeof *hdr);
 574         memset(hdr, 0, sizeof *hdr);
 575         hdr->msg_type = cpu_to_le32(RNDIS_MSG_PACKET);
 576         hdr->msg_len = cpu_to_le32(skb->len);
 577         hdr->data_offset = cpu_to_le32(sizeof(*hdr) - 8);
 578         hdr->data_len = cpu_to_le32(len);
 579
 580         /* FIXME make the last packet always be short ... */
 581         return skb;
 582 }
 583 EXPORT_SYMBOL_GPL(rndis_tx_fixup);
 584
 585
 586 static const struct driver_info rndis_info = {
 587         .description =  "RNDIS device",
 588         .flags =        FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 589         .bind =         rndis_bind,
 590         .unbind =       rndis_unbind,
 591         .status =       rndis_status,
 592         .rx_fixup =     rndis_rx_fixup,
 593         .tx_fixup =     rndis_tx_fixup,
 594 };
 595
 596 static const struct driver_info rndis_poll_status_info = {
 597         .description =  "RNDIS device (poll status before control)",
 598         .flags =        FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 599         .data =         RNDIS_DRIVER_DATA_POLL_STATUS,
 600         .bind =         rndis_bind,
 601         .unbind =       rndis_unbind,
 602         .status =       rndis_status,
 603         .rx_fixup =     rndis_rx_fixup,
 604         .tx_fixup =     rndis_tx_fixup,
 605 };
 606
 607 /*-------------------------------------------------------------------------*/
 608
 609 static const struct usb_device_id       products [] = {
 610 {
 611         /* 2Wire HomePortal 1000SW */
 612         USB_DEVICE_AND_INTERFACE_INFO(0x1630, 0x0042,
 613                                       USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
 614         .driver_info = (unsigned long) &rndis_poll_status_info,
 615 }, {
 616         /* RNDIS is MSFT's un-official variant of CDC ACM */
 617         USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
 618         .driver_info = (unsigned long) &rndis_info,
 619 }, {
 620         /* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
 621         USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
 622         .driver_info = (unsigned long) &rndis_poll_status_info,
 623 }, {
 624         /* RNDIS for tethering */
 625         USB_INTERFACE_INFO(USB_CLASS_WIRELESS_CONTROLLER, 1, 3),
 626         .driver_info = (unsigned long) &rndis_info,
 627 },
 628         { },            // END
 629 };
 630 MODULE_DEVICE_TABLE(usb, products);
 631
 632 static struct usb_driver rndis_driver = {
 633         .name =         "rndis_host",
 634         .id_table =     products,
 635         .probe =        usbnet_probe,
 636         .disconnect =   usbnet_disconnect,
 637         .suspend =      usbnet_suspend,
 638         .resume =       usbnet_resume,
 639         .disable_hub_initiated_lpm = 1,
 640 };
 641
 642 module_usb_driver(rndis_driver);
 643
 644 MODULE_AUTHOR("David Brownell");
 645 MODULE_DESCRIPTION("USB Host side RNDIS driver");
 646 MODULE_LICENSE("GPL");