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                 u32 status = le32_to_cpu(msg->status);
  81
  82                 switch (status) {
  83                 case RNDIS_STATUS_MEDIA_CONNECT:
  84                         dev_info(udev, "rndis media connect\n");
  85                         break;
  86                 case RNDIS_STATUS_MEDIA_DISCONNECT:
  87                         dev_info(udev, "rndis media disconnect\n");
  88                         break;
  89                 default:
  90                         dev_info(udev, "rndis indication: 0x%08x\n", status);
  91                 }
  92         }
  93 }
  94
  95 /*
  96  * RPC done RNDIS-style.  Caller guarantees:
  97  * - message is properly byteswapped
  98  * - there's no other request pending
  99  * - buf can hold up to 1KB response (required by RNDIS spec)
 100  * On return, the first few entries are already byteswapped.
 101  *
 102  * Call context is likely probe(), before interface name is known,
 103  * which is why we won't try to use it in the diagnostics.
 104  */
 105 int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf, int buflen)
 106 {
 107         struct cdc_state        *info = (void *) &dev->data;
 108         struct usb_cdc_notification notification;
 109         int                     master_ifnum;
 110         int                     retval;
 111         int                     partial;
 112         unsigned                count;
 113         u32                     xid = 0, msg_len, request_id, msg_type, rsp,
 114                                 status;
 115
 116         /* REVISIT when this gets called from contexts other than probe() or
 117          * disconnect(): either serialize, or dispatch responses on xid
 118          */
 119
 120         msg_type = le32_to_cpu(buf->msg_type);
 121
 122         /* Issue the request; xid is unique, don't bother byteswapping it */
 123         if (likely(msg_type != RNDIS_MSG_HALT && msg_type != RNDIS_MSG_RESET)) {
 124                 xid = dev->xid++;
 125                 if (!xid)
 126                         xid = dev->xid++;
 127                 buf->request_id = (__force __le32) xid;
 128         }
 129         master_ifnum = info->control->cur_altsetting->desc.bInterfaceNumber;
 130         retval = usb_control_msg(dev->udev,
 131                 usb_sndctrlpipe(dev->udev, 0),
 132                 USB_CDC_SEND_ENCAPSULATED_COMMAND,
 133                 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 134                 0, master_ifnum,
 135                 buf, le32_to_cpu(buf->msg_len),
 136                 RNDIS_CONTROL_TIMEOUT_MS);
 137         if (unlikely(retval < 0 || xid == 0))
 138                 return retval;
 139
 140         /* Some devices don't respond on the control channel until
 141          * polled on the status channel, so do that first. */
 142         if (dev->driver_info->data & RNDIS_DRIVER_DATA_POLL_STATUS) {
 143                 retval = usb_interrupt_msg(
 144                         dev->udev,
 145                         usb_rcvintpipe(dev->udev,
 146                                        dev->status->desc.bEndpointAddress),
 147                         &notification, sizeof(notification), &partial,
 148                         RNDIS_CONTROL_TIMEOUT_MS);
 149                 if (unlikely(retval < 0))
 150                         return retval;
 151         }
 152
 153         /* Poll the control channel; the request probably completed immediately */
 154         rsp = le32_to_cpu(buf->msg_type) | RNDIS_MSG_COMPLETION;
 155         for (count = 0; count < 10; count++) {
 156                 memset(buf, 0, CONTROL_BUFFER_SIZE);
 157                 retval = usb_control_msg(dev->udev,
 158                         usb_rcvctrlpipe(dev->udev, 0),
 159                         USB_CDC_GET_ENCAPSULATED_RESPONSE,
 160                         USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 161                         0, master_ifnum,
 162                         buf, buflen,
 163                         RNDIS_CONTROL_TIMEOUT_MS);
 164                 if (likely(retval >= 8)) {
 165                         msg_type = le32_to_cpu(buf->msg_type);
 166                         msg_len = le32_to_cpu(buf->msg_len);
 167                         status = le32_to_cpu(buf->status);
 168                         request_id = (__force u32) buf->request_id;
 169                         if (likely(msg_type == rsp)) {
 170                                 if (likely(request_id == xid)) {
 171                                         if (unlikely(rsp == RNDIS_MSG_RESET_C))
 172                                                 return 0;
 173                                         if (likely(RNDIS_STATUS_SUCCESS ==
 174                                                         status))
 175                                                 return 0;
 176                                         dev_dbg(&info->control->dev,
 177                                                 "rndis reply status %08x\n",
 178                                                 status);
 179                                         return -EL3RST;
 180                                 }
 181                                 dev_dbg(&info->control->dev,
 182                                         "rndis reply id %d expected %d\n",
 183                                         request_id, xid);
 184                                 /* then likely retry */
 185                         } else switch (msg_type) {
 186                         case RNDIS_MSG_INDICATE: /* fault/event */
 187                                 rndis_msg_indicate(dev, (void *)buf, buflen);
 188                                 break;
 189                         case RNDIS_MSG_KEEPALIVE: { /* ping */
 190                                 struct rndis_keepalive_c *msg = (void *)buf;
 191
 192                                 msg->msg_type = cpu_to_le32(RNDIS_MSG_KEEPALIVE_C);
 193                                 msg->msg_len = cpu_to_le32(sizeof *msg);
 194                                 msg->status = cpu_to_le32(RNDIS_STATUS_SUCCESS);
 195                                 retval = usb_control_msg(dev->udev,
 196                                         usb_sndctrlpipe(dev->udev, 0),
 197                                         USB_CDC_SEND_ENCAPSULATED_COMMAND,
 198                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 199                                         0, master_ifnum,
 200                                         msg, sizeof *msg,
 201                                         RNDIS_CONTROL_TIMEOUT_MS);
 202                                 if (unlikely(retval < 0))
 203                                         dev_dbg(&info->control->dev,
 204                                                 "rndis keepalive err %d\n",
 205                                                 retval);
 206                                 }
 207                                 break;
 208                         default:
 209                                 dev_dbg(&info->control->dev,
 210                                         "unexpected rndis msg %08x len %d\n",
 211                                         le32_to_cpu(buf->msg_type), msg_len);
 212                         }
 213                 } else {
 214                         /* device probably issued a protocol stall; ignore */
 215                         dev_dbg(&info->control->dev,
 216                                 "rndis response error, code %d\n", retval);
 217                 }
 218                 msleep(20);
 219         }
 220         dev_dbg(&info->control->dev, "rndis response timeout\n");
 221         return -ETIMEDOUT;
 222 }
 223 EXPORT_SYMBOL_GPL(rndis_command);
 224
 225 /*
 226  * rndis_query:
 227  *
 228  * Performs a query for @oid along with 0 or more bytes of payload as
 229  * specified by @in_len. If @reply_len is not set to -1 then the reply
 230  * length is checked against this value, resulting in an error if it
 231  * doesn't match.
 232  *
 233  * NOTE: Adding a payload exactly or greater than the size of the expected
 234  * response payload is an evident requirement MSFT added for ActiveSync.
 235  *
 236  * The only exception is for OIDs that return a variably sized response,
 237  * in which case no payload should be added.  This undocumented (and
 238  * nonsensical!) issue was found by sniffing protocol requests from the
 239  * ActiveSync 4.1 Windows driver.
 240  */
 241 static int rndis_query(struct usbnet *dev, struct usb_interface *intf,
 242                 void *buf, u32 oid, u32 in_len,
 243                 void **reply, int *reply_len)
 244 {
 245         int retval;
 246         union {
 247                 void                    *buf;
 248                 struct rndis_msg_hdr    *header;
 249                 struct rndis_query      *get;
 250                 struct rndis_query_c    *get_c;
 251         } u;
 252         u32 off, len;
 253
 254         u.buf = buf;
 255
 256         memset(u.get, 0, sizeof *u.get + in_len);
 257         u.get->msg_type = cpu_to_le32(RNDIS_MSG_QUERY);
 258         u.get->msg_len = cpu_to_le32(sizeof *u.get + in_len);
 259         u.get->oid = cpu_to_le32(oid);
 260         u.get->len = cpu_to_le32(in_len);
 261         u.get->offset = cpu_to_le32(20);
 262
 263         retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 264         if (unlikely(retval < 0)) {
 265                 dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) failed, %d\n",
 266                                 oid, retval);
 267                 return retval;
 268         }
 269
 270         off = le32_to_cpu(u.get_c->offset);
 271         len = le32_to_cpu(u.get_c->len);
 272         if (unlikely((8 + off + len) > CONTROL_BUFFER_SIZE))
 273                 goto response_error;
 274
 275         if (*reply_len != -1 && len != *reply_len)
 276                 goto response_error;
 277
 278         *reply = (unsigned char *) &u.get_c->request_id + off;
 279         *reply_len = len;
 280
 281         return retval;
 282
 283 response_error:
 284         dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) "
 285                         "invalid response - off %d len %d\n",
 286                 oid, off, len);
 287         return -EDOM;
 288 }
 289
 290 /* same as usbnet_netdev_ops but MTU change not allowed */
 291 static const struct net_device_ops rndis_netdev_ops = {
 292         .ndo_open               = usbnet_open,
 293         .ndo_stop               = usbnet_stop,
 294         .ndo_start_xmit         = usbnet_start_xmit,
 295         .ndo_tx_timeout         = usbnet_tx_timeout,
 296         .ndo_set_mac_address    = eth_mac_addr,
 297         .ndo_validate_addr      = eth_validate_addr,
 298 };
 299
 300 int
 301 generic_rndis_bind(struct usbnet *dev, struct usb_interface *intf, int flags)
 302 {
 303         int                     retval;
 304         struct net_device       *net = dev->net;
 305         struct cdc_state        *info = (void *) &dev->data;
 306         union {
 307                 void                    *buf;
 308                 struct rndis_msg_hdr    *header;
 309                 struct rndis_init       *init;
 310                 struct rndis_init_c     *init_c;
 311                 struct rndis_query      *get;
 312                 struct rndis_query_c    *get_c;
 313                 struct rndis_set        *set;
 314                 struct rndis_set_c      *set_c;
 315                 struct rndis_halt       *halt;
 316         } u;
 317         u32                     tmp;
 318         __le32                  phym_unspec, *phym;
 319         int                     reply_len;
 320         unsigned char           *bp;
 321
 322         /* we can't rely on i/o from stack working, or stack allocation */
 323         u.buf = kmalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 324         if (!u.buf)
 325                 return -ENOMEM;
 326         retval = usbnet_generic_cdc_bind(dev, intf);
 327         if (retval < 0)
 328                 goto fail;
 329
 330         u.init->msg_type = cpu_to_le32(RNDIS_MSG_INIT);
 331         u.init->msg_len = cpu_to_le32(sizeof *u.init);
 332         u.init->major_version = cpu_to_le32(1);
 333         u.init->minor_version = cpu_to_le32(0);
 334
 335         /* max transfer (in spec) is 0x4000 at full speed, but for
 336          * TX we'll stick to one Ethernet packet plus RNDIS framing.
 337          * For RX we handle drivers that zero-pad to end-of-packet.
 338          * Don't let userspace change these settings.
 339          *
 340          * NOTE: there still seems to be wierdness here, as if we need
 341          * to do some more things to make sure WinCE targets accept this.
 342          * They default to jumbograms of 8KB or 16KB, which is absurd
 343          * for such low data rates and which is also more than Linux
 344          * can usually expect to allocate for SKB data...
 345          */
 346         net->hard_header_len += sizeof (struct rndis_data_hdr);
 347         dev->hard_mtu = net->mtu + net->hard_header_len;
 348
 349         dev->maxpacket = usb_maxpacket(dev->udev, dev->out, 1);
 350         if (dev->maxpacket == 0) {
 351                 netif_dbg(dev, probe, dev->net,
 352                           "dev->maxpacket can't be 0\n");
 353                 retval = -EINVAL;
 354                 goto fail_and_release;
 355         }
 356
 357         dev->rx_urb_size = dev->hard_mtu + (dev->maxpacket + 1);
 358         dev->rx_urb_size &= ~(dev->maxpacket - 1);
 359         u.init->max_transfer_size = cpu_to_le32(dev->rx_urb_size);
 360
 361         net->netdev_ops = &rndis_netdev_ops;
 362
 363         retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 364         if (unlikely(retval < 0)) {
 365                 /* it might not even be an RNDIS device!! */
 366                 dev_err(&intf->dev, "RNDIS init failed, %d\n", retval);
 367                 goto fail_and_release;
 368         }
 369         tmp = le32_to_cpu(u.init_c->max_transfer_size);
 370         if (tmp < dev->hard_mtu) {
 371                 if (tmp <= net->hard_header_len) {
 372                         dev_err(&intf->dev,
 373                                 "dev can't take %u byte packets (max %u)\n",
 374                                 dev->hard_mtu, tmp);
 375                         retval = -EINVAL;
 376                         goto halt_fail_and_release;
 377                 }
 378                 dev_warn(&intf->dev,
 379                          "dev can't take %u byte packets (max %u), "
 380                          "adjusting MTU to %u\n",
 381                          dev->hard_mtu, tmp, tmp - net->hard_header_len);
 382                 dev->hard_mtu = tmp;
 383                 net->mtu = dev->hard_mtu - net->hard_header_len;
 384         }
 385
 386         /* REVISIT:  peripheral "alignment" request is ignored ... */
 387         dev_dbg(&intf->dev,
 388                 "hard mtu %u (%u from dev), rx buflen %Zu, align %d\n",
 389                 dev->hard_mtu, tmp, dev->rx_urb_size,
 390                 1 << le32_to_cpu(u.init_c->packet_alignment));
 391
 392         /* module has some device initialization code needs to be done right
 393          * after RNDIS_INIT */
 394         if (dev->driver_info->early_init &&
 395                         dev->driver_info->early_init(dev) != 0)
 396                 goto halt_fail_and_release;
 397
 398         /* Check physical medium */
 399         phym = NULL;
 400         reply_len = sizeof *phym;
 401         retval = rndis_query(dev, intf, u.buf,
 402                              RNDIS_OID_GEN_PHYSICAL_MEDIUM,
 403                              0, (void **) &phym, &reply_len);
 404         if (retval != 0 || !phym) {
 405                 /* OID is optional so don't fail here. */
 406                 phym_unspec = cpu_to_le32(RNDIS_PHYSICAL_MEDIUM_UNSPECIFIED);
 407                 phym = &phym_unspec;
 408         }
 409         if ((flags & FLAG_RNDIS_PHYM_WIRELESS) &&
 410             le32_to_cpup(phym) != RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
 411                 netif_dbg(dev, probe, dev->net,
 412                           "driver requires wireless physical medium, but device is not\n");
 413                 retval = -ENODEV;
 414                 goto halt_fail_and_release;
 415         }
 416         if ((flags & FLAG_RNDIS_PHYM_NOT_WIRELESS) &&
 417             le32_to_cpup(phym) == RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
 418                 netif_dbg(dev, probe, dev->net,
 419                           "driver requires non-wireless physical medium, but device is wireless.\n");
 420                 retval = -ENODEV;
 421                 goto halt_fail_and_release;
 422         }
 423
 424         /* Get designated host ethernet address */
 425         reply_len = ETH_ALEN;
 426         retval = rndis_query(dev, intf, u.buf,
 427                              RNDIS_OID_802_3_PERMANENT_ADDRESS,
 428                              48, (void **) &bp, &reply_len);
 429         if (unlikely(retval< 0)) {
 430                 dev_err(&intf->dev, "rndis get ethaddr, %d\n", retval);
 431                 goto halt_fail_and_release;
 432         }
 433         memcpy(net->dev_addr, bp, ETH_ALEN);
 434
 435         /* set a nonzero filter to enable data transfers */
 436         memset(u.set, 0, sizeof *u.set);
 437         u.set->msg_type = cpu_to_le32(RNDIS_MSG_SET);
 438         u.set->msg_len = cpu_to_le32(4 + sizeof *u.set);
 439         u.set->oid = cpu_to_le32(RNDIS_OID_GEN_CURRENT_PACKET_FILTER);
 440         u.set->len = cpu_to_le32(4);
 441         u.set->offset = cpu_to_le32((sizeof *u.set) - 8);
 442         *(__le32 *)(u.buf + sizeof *u.set) = cpu_to_le32(RNDIS_DEFAULT_FILTER);
 443
 444         retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 445         if (unlikely(retval < 0)) {
 446                 dev_err(&intf->dev, "rndis set packet filter, %d\n", retval);
 447                 goto halt_fail_and_release;
 448         }
 449
 450         retval = 0;
 451
 452         kfree(u.buf);
 453         return retval;
 454
 455 halt_fail_and_release:
 456         memset(u.halt, 0, sizeof *u.halt);
 457         u.halt->msg_type = cpu_to_le32(RNDIS_MSG_HALT);
 458         u.halt->msg_len = cpu_to_le32(sizeof *u.halt);
 459         (void) rndis_command(dev, (void *)u.halt, CONTROL_BUFFER_SIZE);
 460 fail_and_release:
 461         usb_set_intfdata(info->data, NULL);
 462         usb_driver_release_interface(driver_of(intf), info->data);
 463         info->data = NULL;
 464 fail:
 465         kfree(u.buf);
 466         return retval;
 467 }
 468 EXPORT_SYMBOL_GPL(generic_rndis_bind);
 469
 470 static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
 471 {
 472         return generic_rndis_bind(dev, intf, FLAG_RNDIS_PHYM_NOT_WIRELESS);
 473 }
 474
 475 void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
 476 {
 477         struct rndis_halt       *halt;
 478
 479         /* try to clear any rndis state/activity (no i/o from stack!) */
 480         halt = kzalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 481         if (halt) {
 482                 halt->msg_type = cpu_to_le32(RNDIS_MSG_HALT);
 483                 halt->msg_len = cpu_to_le32(sizeof *halt);
 484                 (void) rndis_command(dev, (void *)halt, CONTROL_BUFFER_SIZE);
 485                 kfree(halt);
 486         }
 487
 488         usbnet_cdc_unbind(dev, intf);
 489 }
 490 EXPORT_SYMBOL_GPL(rndis_unbind);
 491
 492 /*
 493  * DATA -- host must not write zlps
 494  */
 495 int rndis_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 496 {
 497         /* peripheral may have batched packets to us... */
 498         while (likely(skb->len)) {
 499                 struct rndis_data_hdr   *hdr = (void *)skb->data;
 500                 struct sk_buff          *skb2;
 501                 u32                     msg_type, msg_len, data_offset, data_len;
 502
 503                 msg_type = le32_to_cpu(hdr->msg_type);
 504                 msg_len = le32_to_cpu(hdr->msg_len);
 505                 data_offset = le32_to_cpu(hdr->data_offset);
 506                 data_len = le32_to_cpu(hdr->data_len);
 507
 508                 /* don't choke if we see oob, per-packet data, etc */
 509                 if (unlikely(msg_type != RNDIS_MSG_PACKET || skb->len < msg_len
 510                                 || (data_offset + data_len + 8) > msg_len)) {
 511                         dev->net->stats.rx_frame_errors++;
 512                         netdev_dbg(dev->net, "bad rndis message %d/%d/%d/%d, len %d\n",
 513                                    le32_to_cpu(hdr->msg_type),
 514                                    msg_len, data_offset, data_len, skb->len);
 515                         return 0;
 516                 }
 517                 skb_pull(skb, 8 + data_offset);
 518
 519                 /* at most one packet left? */
 520                 if (likely((data_len - skb->len) <= sizeof *hdr)) {
 521                         skb_trim(skb, data_len);
 522                         break;
 523                 }
 524
 525                 /* try to return all the packets in the batch */
 526                 skb2 = skb_clone(skb, GFP_ATOMIC);
 527                 if (unlikely(!skb2))
 528                         break;
 529                 skb_pull(skb, msg_len - sizeof *hdr);
 530                 skb_trim(skb2, data_len);
 531                 usbnet_skb_return(dev, skb2);
 532         }
 533
 534         /* caller will usbnet_skb_return the remaining packet */
 535         return 1;
 536 }
 537 EXPORT_SYMBOL_GPL(rndis_rx_fixup);
 538
 539 struct sk_buff *
 540 rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 541 {
 542         struct rndis_data_hdr   *hdr;
 543         struct sk_buff          *skb2;
 544         unsigned                len = skb->len;
 545
 546         if (likely(!skb_cloned(skb))) {
 547                 int     room = skb_headroom(skb);
 548
 549                 /* enough head room as-is? */
 550                 if (unlikely((sizeof *hdr) <= room))
 551                         goto fill;
 552
 553                 /* enough room, but needs to be readjusted? */
 554                 room += skb_tailroom(skb);
 555                 if (likely((sizeof *hdr) <= room)) {
 556                         skb->data = memmove(skb->head + sizeof *hdr,
 557                                             skb->data, len);
 558                         skb_set_tail_pointer(skb, len);
 559                         goto fill;
 560                 }
 561         }
 562
 563         /* create a new skb, with the correct size (and tailpad) */
 564         skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
 565         dev_kfree_skb_any(skb);
 566         if (unlikely(!skb2))
 567                 return skb2;
 568         skb = skb2;
 569
 570         /* fill out the RNDIS header.  we won't bother trying to batch
 571          * packets; Linux minimizes wasted bandwidth through tx queues.
 572          */
 573 fill:
 574         hdr = (void *) __skb_push(skb, sizeof *hdr);
 575         memset(hdr, 0, sizeof *hdr);
 576         hdr->msg_type = cpu_to_le32(RNDIS_MSG_PACKET);
 577         hdr->msg_len = cpu_to_le32(skb->len);
 578         hdr->data_offset = cpu_to_le32(sizeof(*hdr) - 8);
 579         hdr->data_len = cpu_to_le32(len);
 580
 581         /* FIXME make the last packet always be short ... */
 582         return skb;
 583 }
 584 EXPORT_SYMBOL_GPL(rndis_tx_fixup);
 585
 586
 587 static const struct driver_info rndis_info = {
 588         .description =  "RNDIS device",
 589         .flags =        FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 590         .bind =         rndis_bind,
 591         .unbind =       rndis_unbind,
 592         .status =       rndis_status,
 593         .rx_fixup =     rndis_rx_fixup,
 594         .tx_fixup =     rndis_tx_fixup,
 595 };
 596
 597 static const struct driver_info rndis_poll_status_info = {
 598         .description =  "RNDIS device (poll status before control)",
 599         .flags =        FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 600         .data =         RNDIS_DRIVER_DATA_POLL_STATUS,
 601         .bind =         rndis_bind,
 602         .unbind =       rndis_unbind,
 603         .status =       rndis_status,
 604         .rx_fixup =     rndis_rx_fixup,
 605         .tx_fixup =     rndis_tx_fixup,
 606 };
 607
 608 /*-------------------------------------------------------------------------*/
 609
 610 static const struct usb_device_id       products [] = {
 611 {
 612         /* 2Wire HomePortal 1000SW */
 613         USB_DEVICE_AND_INTERFACE_INFO(0x1630, 0x0042,
 614                                       USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
 615         .driver_info = (unsigned long) &rndis_poll_status_info,
 616 }, {
 617         /* RNDIS is MSFT's un-official variant of CDC ACM */
 618         USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
 619         .driver_info = (unsigned long) &rndis_info,
 620 }, {
 621         /* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
 622         USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
 623         .driver_info = (unsigned long) &rndis_poll_status_info,
 624 }, {
 625         /* RNDIS for tethering */
 626         USB_INTERFACE_INFO(USB_CLASS_WIRELESS_CONTROLLER, 1, 3),
 627         .driver_info = (unsigned long) &rndis_info,
 628 },
 629         { },            // END
 630 };
 631 MODULE_DEVICE_TABLE(usb, products);
 632
 633 static struct usb_driver rndis_driver = {
 634         .name =         "rndis_host",
 635         .id_table =     products,
 636         .probe =        usbnet_probe,
 637         .disconnect =   usbnet_disconnect,
 638         .suspend =      usbnet_suspend,
 639         .resume =       usbnet_resume,
 640         .disable_hub_initiated_lpm = 1,
 641 };
 642
 643 module_usb_driver(rndis_driver);
 644
 645 MODULE_AUTHOR("David Brownell");
 646 MODULE_DESCRIPTION("USB Host side RNDIS driver");
 647 MODULE_LICENSE("GPL");