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, see <http://www.gnu.org/licenses/>.
  17 */
  18#include <linux/module.h>
  19#include <linux/netdevice.h>
  20#include <linux/etherdevice.h>
  21#include <linux/ethtool.h>
  22#include <linux/workqueue.h>
  23#include <linux/slab.h>
  24#include <linux/mii.h>
  25#include <linux/usb.h>
  26#include <linux/usb/cdc.h>
  27#include <linux/usb/usbnet.h>
  28#include <linux/usb/rndis_host.h>
  29
  30
  31/*
  32 * RNDIS is NDIS remoted over USB.  It's a MSFT variant of CDC ACM ... of
  33 * course ACM was intended for modems, not Ethernet links!  USB's standard
  34 * for Ethernet links is "CDC Ethernet", which is significantly simpler.
  35 *
  36 * NOTE that Microsoft's "RNDIS 1.0" specification is incomplete.  Issues
  37 * include:
  38 *    - Power management in particular relies on information that's scattered
  39 *      through other documentation, and which is incomplete or incorrect even
  40 *      there.
  41 *    - There are various undocumented protocol requirements, such as the
  42 *      need to send unused garbage in control-OUT messages.
  43 *    - In some cases, MS-Windows will emit undocumented requests; this
  44 *      matters more to peripheral implementations than host ones.
  45 *
  46 * Moreover there's a no-open-specs variant of RNDIS called "ActiveSync".
  47 *
  48 * For these reasons and others, ** USE OF RNDIS IS STRONGLY DISCOURAGED ** in
  49 * favor of such non-proprietary alternatives as CDC Ethernet or the newer (and
  50 * currently rare) "Ethernet Emulation Model" (EEM).
  51 */
  52
  53/*
  54 * RNDIS notifications from device: command completion; "reverse"
  55 * keepalives; etc
  56 */
  57void rndis_status(struct usbnet *dev, struct urb *urb)
  58{
  59        netdev_dbg(dev->net, "rndis status urb, len %d stat %d\n",
  60                   urb->actual_length, urb->status);
  61        // FIXME for keepalives, respond immediately (asynchronously)
  62        // if not an RNDIS status, do like cdc_status(dev,urb) does
  63}
  64EXPORT_SYMBOL_GPL(rndis_status);
  65
  66/*
  67 * RNDIS indicate messages.
  68 */
  69static void rndis_msg_indicate(struct usbnet *dev, struct rndis_indicate *msg,
  70                                int buflen)
  71{
  72        struct cdc_state *info = (void *)&dev->data;
  73        struct device *udev = &info->control->dev;
  74
  75        if (dev->driver_info->indication) {
  76                dev->driver_info->indication(dev, msg, buflen);
  77        } else {
  78                u32 status = le32_to_cpu(msg->status);
  79
  80                switch (status) {
  81                case RNDIS_STATUS_MEDIA_CONNECT:
  82                        dev_info(udev, "rndis media connect\n");
  83                        break;
  84                case RNDIS_STATUS_MEDIA_DISCONNECT:
  85                        dev_info(udev, "rndis media disconnect\n");
  86                        break;
  87                default:
  88                        dev_info(udev, "rndis indication: 0x%08x\n", 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 */
 103int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf, int buflen)
 104{
 105        struct cdc_state        *info = (void *) &dev->data;
 106        struct usb_cdc_notification notification;
 107        int                     master_ifnum;
 108        int                     retval;
 109        int                     partial;
 110        unsigned                count;
 111        u32                     xid = 0, msg_len, request_id, msg_type, rsp,
 112                                status;
 113
 114        /* REVISIT when this gets called from contexts other than probe() or
 115         * disconnect(): either serialize, or dispatch responses on xid
 116         */
 117
 118        msg_type = le32_to_cpu(buf->msg_type);
 119
 120        /* Issue the request; xid is unique, don't bother byteswapping it */
 121        if (likely(msg_type != RNDIS_MSG_HALT && msg_type != RNDIS_MSG_RESET)) {
 122                xid = dev->xid++;
 123                if (!xid)
 124                        xid = dev->xid++;
 125                buf->request_id = (__force __le32) xid;
 126        }
 127        master_ifnum = info->control->cur_altsetting->desc.bInterfaceNumber;
 128        retval = usb_control_msg(dev->udev,
 129                usb_sndctrlpipe(dev->udev, 0),
 130                USB_CDC_SEND_ENCAPSULATED_COMMAND,
 131                USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 132                0, master_ifnum,
 133                buf, le32_to_cpu(buf->msg_len),
 134                RNDIS_CONTROL_TIMEOUT_MS);
 135        if (unlikely(retval < 0 || xid == 0))
 136                return retval;
 137
 138        /* Some devices don't respond on the control channel until
 139         * polled on the status channel, so do that first. */
 140        if (dev->driver_info->data & RNDIS_DRIVER_DATA_POLL_STATUS) {
 141                retval = usb_interrupt_msg(
 142                        dev->udev,
 143                        usb_rcvintpipe(dev->udev,
 144                                       dev->status->desc.bEndpointAddress),
 145                        &notification, sizeof(notification), &partial,
 146                        RNDIS_CONTROL_TIMEOUT_MS);
 147                if (unlikely(retval < 0))
 148                        return retval;
 149        }
 150
 151        /* Poll the control channel; the request probably completed immediately */
 152        rsp = le32_to_cpu(buf->msg_type) | RNDIS_MSG_COMPLETION;
 153        for (count = 0; count < 10; count++) {
 154                memset(buf, 0, CONTROL_BUFFER_SIZE);
 155                retval = usb_control_msg(dev->udev,
 156                        usb_rcvctrlpipe(dev->udev, 0),
 157                        USB_CDC_GET_ENCAPSULATED_RESPONSE,
 158                        USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 159                        0, master_ifnum,
 160                        buf, buflen,
 161                        RNDIS_CONTROL_TIMEOUT_MS);
 162                if (likely(retval >= 8)) {
 163                        msg_type = le32_to_cpu(buf->msg_type);
 164                        msg_len = le32_to_cpu(buf->msg_len);
 165                        status = le32_to_cpu(buf->status);
 166                        request_id = (__force u32) buf->request_id;
 167                        if (likely(msg_type == rsp)) {
 168                                if (likely(request_id == xid)) {
 169                                        if (unlikely(rsp == RNDIS_MSG_RESET_C))
 170                                                return 0;
 171                                        if (likely(RNDIS_STATUS_SUCCESS ==
 172                                                        status))
 173                                                return 0;
 174                                        dev_dbg(&info->control->dev,
 175                                                "rndis reply status %08x\n",
 176                                                status);
 177                                        return -EL3RST;
 178                                }
 179                                dev_dbg(&info->control->dev,
 180                                        "rndis reply id %d expected %d\n",
 181                                        request_id, xid);
 182                                /* then likely retry */
 183                        } else switch (msg_type) {
 184                        case RNDIS_MSG_INDICATE: /* fault/event */
 185                                rndis_msg_indicate(dev, (void *)buf, buflen);
 186                                break;
 187                        case RNDIS_MSG_KEEPALIVE: { /* ping */
 188                                struct rndis_keepalive_c *msg = (void *)buf;
 189
 190                                msg->msg_type = cpu_to_le32(RNDIS_MSG_KEEPALIVE_C);
 191                                msg->msg_len = cpu_to_le32(sizeof *msg);
 192                                msg->status = cpu_to_le32(RNDIS_STATUS_SUCCESS);
 193                                retval = usb_control_msg(dev->udev,
 194                                        usb_sndctrlpipe(dev->udev, 0),
 195                                        USB_CDC_SEND_ENCAPSULATED_COMMAND,
 196                                        USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 197                                        0, master_ifnum,
 198                                        msg, sizeof *msg,
 199                                        RNDIS_CONTROL_TIMEOUT_MS);
 200                                if (unlikely(retval < 0))
 201                                        dev_dbg(&info->control->dev,
 202                                                "rndis keepalive err %d\n",
 203                                                retval);
 204                                }
 205                                break;
 206                        default:
 207                                dev_dbg(&info->control->dev,
 208                                        "unexpected rndis msg %08x len %d\n",
 209                                        le32_to_cpu(buf->msg_type), msg_len);
 210                        }
 211                } else {
 212                        /* device probably issued a protocol stall; ignore */
 213                        dev_dbg(&info->control->dev,
 214                                "rndis response error, code %d\n", retval);
 215                }
 216                msleep(20);
 217        }
 218        dev_dbg(&info->control->dev, "rndis response timeout\n");
 219        return -ETIMEDOUT;
 220}
 221EXPORT_SYMBOL_GPL(rndis_command);
 222
 223/*
 224 * rndis_query:
 225 *
 226 * Performs a query for @oid along with 0 or more bytes of payload as
 227 * specified by @in_len. If @reply_len is not set to -1 then the reply
 228 * length is checked against this value, resulting in an error if it
 229 * doesn't match.
 230 *
 231 * NOTE: Adding a payload exactly or greater than the size of the expected
 232 * response payload is an evident requirement MSFT added for ActiveSync.
 233 *
 234 * The only exception is for OIDs that return a variably sized response,
 235 * in which case no payload should be added.  This undocumented (and
 236 * nonsensical!) issue was found by sniffing protocol requests from the
 237 * ActiveSync 4.1 Windows driver.
 238 */
 239static int rndis_query(struct usbnet *dev, struct usb_interface *intf,
 240                void *buf, u32 oid, u32 in_len,
 241                void **reply, int *reply_len)
 242{
 243        int retval;
 244        union {
 245                void                    *buf;
 246                struct rndis_msg_hdr    *header;
 247                struct rndis_query      *get;
 248                struct rndis_query_c    *get_c;
 249        } u;
 250        u32 off, len;
 251
 252        u.buf = buf;
 253
 254        memset(u.get, 0, sizeof *u.get + in_len);
 255        u.get->msg_type = cpu_to_le32(RNDIS_MSG_QUERY);
 256        u.get->msg_len = cpu_to_le32(sizeof *u.get + in_len);
 257        u.get->oid = cpu_to_le32(oid);
 258        u.get->len = cpu_to_le32(in_len);
 259        u.get->offset = cpu_to_le32(20);
 260
 261        retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 262        if (unlikely(retval < 0)) {
 263                dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) failed, %d\n",
 264                                oid, retval);
 265                return retval;
 266        }
 267
 268        off = le32_to_cpu(u.get_c->offset);
 269        len = le32_to_cpu(u.get_c->len);
 270        if (unlikely((8 + off + len) > CONTROL_BUFFER_SIZE))
 271                goto response_error;
 272
 273        if (*reply_len != -1 && len != *reply_len)
 274                goto response_error;
 275
 276        *reply = (unsigned char *) &u.get_c->request_id + off;
 277        *reply_len = len;
 278
 279        return retval;
 280
 281response_error:
 282        dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) "
 283                        "invalid response - off %d len %d\n",
 284                oid, off, len);
 285        return -EDOM;
 286}
 287
 288/* same as usbnet_netdev_ops but MTU change not allowed */
 289static const struct net_device_ops rndis_netdev_ops = {
 290        .ndo_open               = usbnet_open,
 291        .ndo_stop               = usbnet_stop,
 292        .ndo_start_xmit         = usbnet_start_xmit,
 293        .ndo_tx_timeout         = usbnet_tx_timeout,
 294        .ndo_set_mac_address    = eth_mac_addr,
 295        .ndo_validate_addr      = eth_validate_addr,
 296};
 297
 298int
 299generic_rndis_bind(struct usbnet *dev, struct usb_interface *intf, int flags)
 300{
 301        int                     retval;
 302        struct net_device       *net = dev->net;
 303        struct cdc_state        *info = (void *) &dev->data;
 304        union {
 305                void                    *buf;
 306                struct rndis_msg_hdr    *header;
 307                struct rndis_init       *init;
 308                struct rndis_init_c     *init_c;
 309                struct rndis_query      *get;
 310                struct rndis_query_c    *get_c;
 311                struct rndis_set        *set;
 312                struct rndis_set_c      *set_c;
 313                struct rndis_halt       *halt;
 314        } u;
 315        u32                     tmp;
 316        __le32                  phym_unspec, *phym;
 317        int                     reply_len;
 318        unsigned char           *bp;
 319
 320        /* we can't rely on i/o from stack working, or stack allocation */
 321        u.buf = kmalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 322        if (!u.buf)
 323                return -ENOMEM;
 324        retval = usbnet_generic_cdc_bind(dev, intf);
 325        if (retval < 0)
 326                goto fail;
 327
 328        u.init->msg_type = cpu_to_le32(RNDIS_MSG_INIT);
 329        u.init->msg_len = cpu_to_le32(sizeof *u.init);
 330        u.init->major_version = cpu_to_le32(1);
 331        u.init->minor_version = cpu_to_le32(0);
 332
 333        /* max transfer (in spec) is 0x4000 at full speed, but for
 334         * TX we'll stick to one Ethernet packet plus RNDIS framing.
 335         * For RX we handle drivers that zero-pad to end-of-packet.
 336         * Don't let userspace change these settings.
 337         *
 338         * NOTE: there still seems to be wierdness here, as if we need
 339         * to do some more things to make sure WinCE targets accept this.
 340         * They default to jumbograms of 8KB or 16KB, which is absurd
 341         * for such low data rates and which is also more than Linux
 342         * can usually expect to allocate for SKB data...
 343         */
 344        net->hard_header_len += sizeof (struct rndis_data_hdr);
 345        dev->hard_mtu = net->mtu + net->hard_header_len;
 346
 347        dev->maxpacket = usb_maxpacket(dev->udev, dev->out, 1);
 348        if (dev->maxpacket == 0) {
 349                netif_dbg(dev, probe, dev->net,
 350                          "dev->maxpacket can't be 0\n");
 351                retval = -EINVAL;
 352                goto fail_and_release;
 353        }
 354
 355        dev->rx_urb_size = dev->hard_mtu + (dev->maxpacket + 1);
 356        dev->rx_urb_size &= ~(dev->maxpacket - 1);
 357        u.init->max_transfer_size = cpu_to_le32(dev->rx_urb_size);
 358
 359        net->netdev_ops = &rndis_netdev_ops;
 360
 361        retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 362        if (unlikely(retval < 0)) {
 363                /* it might not even be an RNDIS device!! */
 364                dev_err(&intf->dev, "RNDIS init failed, %d\n", retval);
 365                goto fail_and_release;
 366        }
 367        tmp = le32_to_cpu(u.init_c->max_transfer_size);
 368        if (tmp < dev->hard_mtu) {
 369                if (tmp <= net->hard_header_len) {
 370                        dev_err(&intf->dev,
 371                                "dev can't take %u byte packets (max %u)\n",
 372                                dev->hard_mtu, tmp);
 373                        retval = -EINVAL;
 374                        goto halt_fail_and_release;
 375                }
 376                dev_warn(&intf->dev,
 377                         "dev can't take %u byte packets (max %u), "
 378                         "adjusting MTU to %u\n",
 379                         dev->hard_mtu, tmp, tmp - net->hard_header_len);
 380                dev->hard_mtu = tmp;
 381                net->mtu = dev->hard_mtu - net->hard_header_len;
 382        }
 383
 384        /* REVISIT:  peripheral "alignment" request is ignored ... */
 385        dev_dbg(&intf->dev,
 386                "hard mtu %u (%u from dev), rx buflen %Zu, align %d\n",
 387                dev->hard_mtu, tmp, dev->rx_urb_size,
 388                1 << le32_to_cpu(u.init_c->packet_alignment));
 389
 390        /* module has some device initialization code needs to be done right
 391         * after RNDIS_INIT */
 392        if (dev->driver_info->early_init &&
 393                        dev->driver_info->early_init(dev) != 0)
 394                goto halt_fail_and_release;
 395
 396        /* Check physical medium */
 397        phym = NULL;
 398        reply_len = sizeof *phym;
 399        retval = rndis_query(dev, intf, u.buf,
 400                             RNDIS_OID_GEN_PHYSICAL_MEDIUM,
 401                             0, (void **) &phym, &reply_len);
 402        if (retval != 0 || !phym) {
 403                /* OID is optional so don't fail here. */
 404                phym_unspec = cpu_to_le32(RNDIS_PHYSICAL_MEDIUM_UNSPECIFIED);
 405                phym = &phym_unspec;
 406        }
 407        if ((flags & FLAG_RNDIS_PHYM_WIRELESS) &&
 408            le32_to_cpup(phym) != RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
 409                netif_dbg(dev, probe, dev->net,
 410                          "driver requires wireless physical medium, but device is not\n");
 411                retval = -ENODEV;
 412                goto halt_fail_and_release;
 413        }
 414        if ((flags & FLAG_RNDIS_PHYM_NOT_WIRELESS) &&
 415            le32_to_cpup(phym) == RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
 416                netif_dbg(dev, probe, dev->net,
 417                          "driver requires non-wireless physical medium, but device is wireless.\n");
 418                retval = -ENODEV;
 419                goto halt_fail_and_release;
 420        }
 421
 422        /* Get designated host ethernet address */
 423        reply_len = ETH_ALEN;
 424        retval = rndis_query(dev, intf, u.buf,
 425                             RNDIS_OID_802_3_PERMANENT_ADDRESS,
 426                             48, (void **) &bp, &reply_len);
 427        if (unlikely(retval< 0)) {
 428                dev_err(&intf->dev, "rndis get ethaddr, %d\n", retval);
 429                goto halt_fail_and_release;
 430        }
 431        memcpy(net->dev_addr, bp, ETH_ALEN);
 432
 433        /* set a nonzero filter to enable data transfers */
 434        memset(u.set, 0, sizeof *u.set);
 435        u.set->msg_type = cpu_to_le32(RNDIS_MSG_SET);
 436        u.set->msg_len = cpu_to_le32(4 + sizeof *u.set);
 437        u.set->oid = cpu_to_le32(RNDIS_OID_GEN_CURRENT_PACKET_FILTER);
 438        u.set->len = cpu_to_le32(4);
 439        u.set->offset = cpu_to_le32((sizeof *u.set) - 8);
 440        *(__le32 *)(u.buf + sizeof *u.set) = cpu_to_le32(RNDIS_DEFAULT_FILTER);
 441
 442        retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
 443        if (unlikely(retval < 0)) {
 444                dev_err(&intf->dev, "rndis set packet filter, %d\n", retval);
 445                goto halt_fail_and_release;
 446        }
 447
 448        retval = 0;
 449
 450        kfree(u.buf);
 451        return retval;
 452
 453halt_fail_and_release:
 454        memset(u.halt, 0, sizeof *u.halt);
 455        u.halt->msg_type = cpu_to_le32(RNDIS_MSG_HALT);
 456        u.halt->msg_len = cpu_to_le32(sizeof *u.halt);
 457        (void) rndis_command(dev, (void *)u.halt, CONTROL_BUFFER_SIZE);
 458fail_and_release:
 459        usb_set_intfdata(info->data, NULL);
 460        usb_driver_release_interface(driver_of(intf), info->data);
 461        info->data = NULL;
 462fail:
 463        kfree(u.buf);
 464        return retval;
 465}
 466EXPORT_SYMBOL_GPL(generic_rndis_bind);
 467
 468static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
 469{
 470        return generic_rndis_bind(dev, intf, FLAG_RNDIS_PHYM_NOT_WIRELESS);
 471}
 472
 473void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
 474{
 475        struct rndis_halt       *halt;
 476
 477        /* try to clear any rndis state/activity (no i/o from stack!) */
 478        halt = kzalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 479        if (halt) {
 480                halt->msg_type = cpu_to_le32(RNDIS_MSG_HALT);
 481                halt->msg_len = cpu_to_le32(sizeof *halt);
 482                (void) rndis_command(dev, (void *)halt, CONTROL_BUFFER_SIZE);
 483                kfree(halt);
 484        }
 485
 486        usbnet_cdc_unbind(dev, intf);
 487}
 488EXPORT_SYMBOL_GPL(rndis_unbind);
 489
 490/*
 491 * DATA -- host must not write zlps
 492 */
 493int rndis_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 494{
 495        /* This check is no longer done by usbnet */
 496        if (skb->len < dev->net->hard_header_len)
 497                return 0;
 498
 499        /* peripheral may have batched packets to us... */
 500        while (likely(skb->len)) {
 501                struct rndis_data_hdr   *hdr = (void *)skb->data;
 502                struct sk_buff          *skb2;
 503                u32                     msg_type, msg_len, data_offset, data_len;
 504
 505                msg_type = le32_to_cpu(hdr->msg_type);
 506                msg_len = le32_to_cpu(hdr->msg_len);
 507                data_offset = le32_to_cpu(hdr->data_offset);
 508                data_len = le32_to_cpu(hdr->data_len);
 509
 510                /* don't choke if we see oob, per-packet data, etc */
 511                if (unlikely(msg_type != RNDIS_MSG_PACKET || skb->len < msg_len
 512                                || (data_offset + data_len + 8) > msg_len)) {
 513                        dev->net->stats.rx_frame_errors++;
 514                        netdev_dbg(dev->net, "bad rndis message %d/%d/%d/%d, len %d\n",
 515                                   le32_to_cpu(hdr->msg_type),
 516                                   msg_len, data_offset, data_len, skb->len);
 517                        return 0;
 518                }
 519                skb_pull(skb, 8 + data_offset);
 520
 521                /* at most one packet left? */
 522                if (likely((data_len - skb->len) <= sizeof *hdr)) {
 523                        skb_trim(skb, data_len);
 524                        break;
 525                }
 526
 527                /* try to return all the packets in the batch */
 528                skb2 = skb_clone(skb, GFP_ATOMIC);
 529                if (unlikely(!skb2))
 530                        break;
 531                skb_pull(skb, msg_len - sizeof *hdr);
 532                skb_trim(skb2, data_len);
 533                usbnet_skb_return(dev, skb2);
 534        }
 535
 536        /* caller will usbnet_skb_return the remaining packet */
 537        return 1;
 538}
 539EXPORT_SYMBOL_GPL(rndis_rx_fixup);
 540
 541struct sk_buff *
 542rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 543{
 544        struct rndis_data_hdr   *hdr;
 545        struct sk_buff          *skb2;
 546        unsigned                len = skb->len;
 547
 548        if (likely(!skb_cloned(skb))) {
 549                int     room = skb_headroom(skb);
 550
 551                /* enough head room as-is? */
 552                if (unlikely((sizeof *hdr) <= room))
 553                        goto fill;
 554
 555                /* enough room, but needs to be readjusted? */
 556                room += skb_tailroom(skb);
 557                if (likely((sizeof *hdr) <= room)) {
 558                        skb->data = memmove(skb->head + sizeof *hdr,
 559                                            skb->data, len);
 560                        skb_set_tail_pointer(skb, len);
 561                        goto fill;
 562                }
 563        }
 564
 565        /* create a new skb, with the correct size (and tailpad) */
 566        skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
 567        dev_kfree_skb_any(skb);
 568        if (unlikely(!skb2))
 569                return skb2;
 570        skb = skb2;
 571
 572        /* fill out the RNDIS header.  we won't bother trying to batch
 573         * packets; Linux minimizes wasted bandwidth through tx queues.
 574         */
 575fill:
 576        hdr = (void *) __skb_push(skb, sizeof *hdr);
 577        memset(hdr, 0, sizeof *hdr);
 578        hdr->msg_type = cpu_to_le32(RNDIS_MSG_PACKET);
 579        hdr->msg_len = cpu_to_le32(skb->len);
 580        hdr->data_offset = cpu_to_le32(sizeof(*hdr) - 8);
 581        hdr->data_len = cpu_to_le32(len);
 582
 583        /* FIXME make the last packet always be short ... */
 584        return skb;
 585}
 586EXPORT_SYMBOL_GPL(rndis_tx_fixup);
 587
 588
 589static const struct driver_info rndis_info = {
 590        .description =  "RNDIS device",
 591        .flags =        FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 592        .bind =         rndis_bind,
 593        .unbind =       rndis_unbind,
 594        .status =       rndis_status,
 595        .rx_fixup =     rndis_rx_fixup,
 596        .tx_fixup =     rndis_tx_fixup,
 597};
 598
 599static const struct driver_info rndis_poll_status_info = {
 600        .description =  "RNDIS device (poll status before control)",
 601        .flags =        FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 602        .data =         RNDIS_DRIVER_DATA_POLL_STATUS,
 603        .bind =         rndis_bind,
 604        .unbind =       rndis_unbind,
 605        .status =       rndis_status,
 606        .rx_fixup =     rndis_rx_fixup,
 607        .tx_fixup =     rndis_tx_fixup,
 608};
 609
 610/*-------------------------------------------------------------------------*/
 611
 612static const struct usb_device_id       products [] = {
 613{
 614        /* 2Wire HomePortal 1000SW */
 615        USB_DEVICE_AND_INTERFACE_INFO(0x1630, 0x0042,
 616                                      USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
 617        .driver_info = (unsigned long) &rndis_poll_status_info,
 618}, {
 619        /* RNDIS is MSFT's un-official variant of CDC ACM */
 620        USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
 621        .driver_info = (unsigned long) &rndis_info,
 622}, {
 623        /* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
 624        USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
 625        .driver_info = (unsigned long) &rndis_poll_status_info,
 626}, {
 627        /* RNDIS for tethering */
 628        USB_INTERFACE_INFO(USB_CLASS_WIRELESS_CONTROLLER, 1, 3),
 629        .driver_info = (unsigned long) &rndis_info,
 630},
 631        { },            // END
 632};
 633MODULE_DEVICE_TABLE(usb, products);
 634
 635static struct usb_driver rndis_driver = {
 636        .name =         "rndis_host",
 637        .id_table =     products,
 638        .probe =        usbnet_probe,
 639        .disconnect =   usbnet_disconnect,
 640        .suspend =      usbnet_suspend,
 641        .resume =       usbnet_resume,
 642        .disable_hub_initiated_lpm = 1,
 643};
 644
 645module_usb_driver(rndis_driver);
 646
 647MODULE_AUTHOR("David Brownell");
 648MODULE_DESCRIPTION("USB Host side RNDIS driver");
 649MODULE_LICENSE("GPL");
 650