linux/drivers/net/usb/rndis_host.c
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   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 */
  59void 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}
  66EXPORT_SYMBOL_GPL(rndis_status);
  67
  68/*
  69 * RNDIS indicate messages.
  70 */
  71static 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 */
 105int 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}
 223EXPORT_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 */
 241static 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
 283response_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 */
 291static 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
 300int
 301generic_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        memcpy(net->perm_addr, bp, ETH_ALEN);
 435
 436        /* set a nonzero filter to enable data transfers */
 437        memset(u.set, 0, sizeof *u.set);
 438        u.set->msg_type = cpu_to_le32(RNDIS_MSG_SET);
 439        u.set->msg_len = cpu_to_le32(4 + sizeof *u.set);
 440        u.set->oid = cpu_to_le32(RNDIS_OID_GEN_CURRENT_PACKET_FILTER);
 441        u.set->len = cpu_to_le32(4);
 442        u.set->offset = cpu_to_le32((sizeof *u.set) - 8);
 443        *(__le32 *)(u.buf + sizeof *u.set) = cpu_to_le32(RNDIS_DEFAULT_FILTER);
 444
 445        retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 446        if (unlikely(retval < 0)) {
 447                dev_err(&intf->dev, "rndis set packet filter, %d\n", retval);
 448                goto halt_fail_and_release;
 449        }
 450
 451        retval = 0;
 452
 453        kfree(u.buf);
 454        return retval;
 455
 456halt_fail_and_release:
 457        memset(u.halt, 0, sizeof *u.halt);
 458        u.halt->msg_type = cpu_to_le32(RNDIS_MSG_HALT);
 459        u.halt->msg_len = cpu_to_le32(sizeof *u.halt);
 460        (void) rndis_command(dev, (void *)u.halt, CONTROL_BUFFER_SIZE);
 461fail_and_release:
 462        usb_set_intfdata(info->data, NULL);
 463        usb_driver_release_interface(driver_of(intf), info->data);
 464        info->data = NULL;
 465fail:
 466        kfree(u.buf);
 467        return retval;
 468}
 469EXPORT_SYMBOL_GPL(generic_rndis_bind);
 470
 471static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
 472{
 473        return generic_rndis_bind(dev, intf, FLAG_RNDIS_PHYM_NOT_WIRELESS);
 474}
 475
 476void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
 477{
 478        struct rndis_halt       *halt;
 479
 480        /* try to clear any rndis state/activity (no i/o from stack!) */
 481        halt = kzalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 482        if (halt) {
 483                halt->msg_type = cpu_to_le32(RNDIS_MSG_HALT);
 484                halt->msg_len = cpu_to_le32(sizeof *halt);
 485                (void) rndis_command(dev, (void *)halt, CONTROL_BUFFER_SIZE);
 486                kfree(halt);
 487        }
 488
 489        usbnet_cdc_unbind(dev, intf);
 490}
 491EXPORT_SYMBOL_GPL(rndis_unbind);
 492
 493/*
 494 * DATA -- host must not write zlps
 495 */
 496int rndis_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 497{
 498        /* peripheral may have batched packets to us... */
 499        while (likely(skb->len)) {
 500                struct rndis_data_hdr   *hdr = (void *)skb->data;
 501                struct sk_buff          *skb2;
 502                u32                     msg_type, msg_len, data_offset, data_len;
 503
 504                msg_type = le32_to_cpu(hdr->msg_type);
 505                msg_len = le32_to_cpu(hdr->msg_len);
 506                data_offset = le32_to_cpu(hdr->data_offset);
 507                data_len = le32_to_cpu(hdr->data_len);
 508
 509                /* don't choke if we see oob, per-packet data, etc */
 510                if (unlikely(msg_type != RNDIS_MSG_PACKET || skb->len < msg_len
 511                                || (data_offset + data_len + 8) > msg_len)) {
 512                        dev->net->stats.rx_frame_errors++;
 513                        netdev_dbg(dev->net, "bad rndis message %d/%d/%d/%d, len %d\n",
 514                                   le32_to_cpu(hdr->msg_type),
 515                                   msg_len, data_offset, data_len, skb->len);
 516                        return 0;
 517                }
 518                skb_pull(skb, 8 + data_offset);
 519
 520                /* at most one packet left? */
 521                if (likely((data_len - skb->len) <= sizeof *hdr)) {
 522                        skb_trim(skb, data_len);
 523                        break;
 524                }
 525
 526                /* try to return all the packets in the batch */
 527                skb2 = skb_clone(skb, GFP_ATOMIC);
 528                if (unlikely(!skb2))
 529                        break;
 530                skb_pull(skb, msg_len - sizeof *hdr);
 531                skb_trim(skb2, data_len);
 532                usbnet_skb_return(dev, skb2);
 533        }
 534
 535        /* caller will usbnet_skb_return the remaining packet */
 536        return 1;
 537}
 538EXPORT_SYMBOL_GPL(rndis_rx_fixup);
 539
 540struct sk_buff *
 541rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 542{
 543        struct rndis_data_hdr   *hdr;
 544        struct sk_buff          *skb2;
 545        unsigned                len = skb->len;
 546
 547        if (likely(!skb_cloned(skb))) {
 548                int     room = skb_headroom(skb);
 549
 550                /* enough head room as-is? */
 551                if (unlikely((sizeof *hdr) <= room))
 552                        goto fill;
 553
 554                /* enough room, but needs to be readjusted? */
 555                room += skb_tailroom(skb);
 556                if (likely((sizeof *hdr) <= room)) {
 557                        skb->data = memmove(skb->head + sizeof *hdr,
 558                                            skb->data, len);
 559                        skb_set_tail_pointer(skb, len);
 560                        goto fill;
 561                }
 562        }
 563
 564        /* create a new skb, with the correct size (and tailpad) */
 565        skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
 566        dev_kfree_skb_any(skb);
 567        if (unlikely(!skb2))
 568                return skb2;
 569        skb = skb2;
 570
 571        /* fill out the RNDIS header.  we won't bother trying to batch
 572         * packets; Linux minimizes wasted bandwidth through tx queues.
 573         */
 574fill:
 575        hdr = (void *) __skb_push(skb, sizeof *hdr);
 576        memset(hdr, 0, sizeof *hdr);
 577        hdr->msg_type = cpu_to_le32(RNDIS_MSG_PACKET);
 578        hdr->msg_len = cpu_to_le32(skb->len);
 579        hdr->data_offset = cpu_to_le32(sizeof(*hdr) - 8);
 580        hdr->data_len = cpu_to_le32(len);
 581
 582        /* FIXME make the last packet always be short ... */
 583        return skb;
 584}
 585EXPORT_SYMBOL_GPL(rndis_tx_fixup);
 586
 587
 588static const struct driver_info rndis_info = {
 589        .description =  "RNDIS device",
 590        .flags =        FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 591        .bind =         rndis_bind,
 592        .unbind =       rndis_unbind,
 593        .status =       rndis_status,
 594        .rx_fixup =     rndis_rx_fixup,
 595        .tx_fixup =     rndis_tx_fixup,
 596};
 597
 598static const struct driver_info rndis_poll_status_info = {
 599        .description =  "RNDIS device (poll status before control)",
 600        .flags =        FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 601        .data =         RNDIS_DRIVER_DATA_POLL_STATUS,
 602        .bind =         rndis_bind,
 603        .unbind =       rndis_unbind,
 604        .status =       rndis_status,
 605        .rx_fixup =     rndis_rx_fixup,
 606        .tx_fixup =     rndis_tx_fixup,
 607};
 608
 609/*-------------------------------------------------------------------------*/
 610
 611static const struct usb_device_id       products [] = {
 612{
 613        /* 2Wire HomePortal 1000SW */
 614        USB_DEVICE_AND_INTERFACE_INFO(0x1630, 0x0042,
 615                                      USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
 616        .driver_info = (unsigned long) &rndis_poll_status_info,
 617}, {
 618        /* RNDIS is MSFT's un-official variant of CDC ACM */
 619        USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
 620        .driver_info = (unsigned long) &rndis_info,
 621}, {
 622        /* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
 623        USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
 624        .driver_info = (unsigned long) &rndis_poll_status_info,
 625}, {
 626        /* RNDIS for tethering */
 627        USB_INTERFACE_INFO(USB_CLASS_WIRELESS_CONTROLLER, 1, 3),
 628        .driver_info = (unsigned long) &rndis_info,
 629},
 630        { },            // END
 631};
 632MODULE_DEVICE_TABLE(usb, products);
 633
 634static struct usb_driver rndis_driver = {
 635        .name =         "rndis_host",
 636        .id_table =     products,
 637        .probe =        usbnet_probe,
 638        .disconnect =   usbnet_disconnect,
 639        .suspend =      usbnet_suspend,
 640        .resume =       usbnet_resume,
 641        .disable_hub_initiated_lpm = 1,
 642};
 643
 644module_usb_driver(rndis_driver);
 645
 646MODULE_AUTHOR("David Brownell");
 647MODULE_DESCRIPTION("USB Host side RNDIS driver");
 648MODULE_LICENSE("GPL");
 649