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
  20 // #define      DEBUG                   // error path messages, extra info
  21 // #define      VERBOSE                 // more; success messages
  22
  23 #include <linux/module.h>
  24 #include <linux/init.h>
  25 #include <linux/netdevice.h>
  26 #include <linux/etherdevice.h>
  27 #include <linux/ethtool.h>
  28 #include <linux/workqueue.h>
  29 #include <linux/mii.h>
  30 #include <linux/usb.h>
  31 #include <linux/usb/cdc.h>
  32
  33 #include "usbnet.h"
  34
  35
  36 /*
  37  * RNDIS is NDIS remoted over USB.  It's a MSFT variant of CDC ACM ... of
  38  * course ACM was intended for modems, not Ethernet links!  USB's standard
  39  * for Ethernet links is "CDC Ethernet", which is significantly simpler.
  40  *
  41  * NOTE that Microsoft's "RNDIS 1.0" specification is incomplete.  Issues
  42  * include:
  43  *    - Power management in particular relies on information that's scattered
  44  *      through other documentation, and which is incomplete or incorrect even
  45  *      there.
  46  *    - There are various undocumented protocol requirements, such as the
  47  *      need to send unused garbage in control-OUT messages.
  48  *    - In some cases, MS-Windows will emit undocumented requests; this
  49  *      matters more to peripheral implementations than host ones.
  50  *
  51  * Moreover there's a no-open-specs variant of RNDIS called "ActiveSync".
  52  *
  53  * For these reasons and others, ** USE OF RNDIS IS STRONGLY DISCOURAGED ** in
  54  * favor of such non-proprietary alternatives as CDC Ethernet or the newer (and
  55  * currently rare) "Ethernet Emulation Model" (EEM).
  56  */
  57
  58 /*
  59  * CONTROL uses CDC "encapsulated commands" with funky notifications.
  60  *  - control-out:  SEND_ENCAPSULATED
  61  *  - interrupt-in:  RESPONSE_AVAILABLE
  62  *  - control-in:  GET_ENCAPSULATED
  63  *
  64  * We'll try to ignore the RESPONSE_AVAILABLE notifications.
  65  *
  66  * REVISIT some RNDIS implementations seem to have curious issues still
  67  * to be resolved.
  68  */
  69 struct rndis_msg_hdr {
  70         __le32  msg_type;                       /* RNDIS_MSG_* */
  71         __le32  msg_len;
  72         // followed by data that varies between messages
  73         __le32  request_id;
  74         __le32  status;
  75         // ... and more
  76 } __attribute__ ((packed));
  77
  78 /* MS-Windows uses this strange size, but RNDIS spec says 1024 minimum */
  79 #define CONTROL_BUFFER_SIZE             1025
  80
  81 /* RNDIS defines an (absurdly huge) 10 second control timeout,
  82  * but ActiveSync seems to use a more usual 5 second timeout
  83  * (which matches the USB 2.0 spec).
  84  */
  85 #define RNDIS_CONTROL_TIMEOUT_MS        (5 * 1000)
  86
  87
  88 #define ccpu2 __constant_cpu_to_le32
  89
  90 #define RNDIS_MSG_COMPLETION    ccpu2(0x80000000)
  91
  92 /* codes for "msg_type" field of rndis messages;
  93  * only the data channel uses packet messages (maybe batched);
  94  * everything else goes on the control channel.
  95  */
  96 #define RNDIS_MSG_PACKET        ccpu2(0x00000001)       /* 1-N packets */
  97 #define RNDIS_MSG_INIT          ccpu2(0x00000002)
  98 #define RNDIS_MSG_INIT_C        (RNDIS_MSG_INIT|RNDIS_MSG_COMPLETION)
  99 #define RNDIS_MSG_HALT          ccpu2(0x00000003)
 100 #define RNDIS_MSG_QUERY         ccpu2(0x00000004)
 101 #define RNDIS_MSG_QUERY_C       (RNDIS_MSG_QUERY|RNDIS_MSG_COMPLETION)
 102 #define RNDIS_MSG_SET           ccpu2(0x00000005)
 103 #define RNDIS_MSG_SET_C         (RNDIS_MSG_SET|RNDIS_MSG_COMPLETION)
 104 #define RNDIS_MSG_RESET         ccpu2(0x00000006)
 105 #define RNDIS_MSG_RESET_C       (RNDIS_MSG_RESET|RNDIS_MSG_COMPLETION)
 106 #define RNDIS_MSG_INDICATE      ccpu2(0x00000007)
 107 #define RNDIS_MSG_KEEPALIVE     ccpu2(0x00000008)
 108 #define RNDIS_MSG_KEEPALIVE_C   (RNDIS_MSG_KEEPALIVE|RNDIS_MSG_COMPLETION)
 109
 110 /* codes for "status" field of completion messages */
 111 #define RNDIS_STATUS_SUCCESS            ccpu2(0x00000000)
 112 #define RNDIS_STATUS_FAILURE            ccpu2(0xc0000001)
 113 #define RNDIS_STATUS_INVALID_DATA       ccpu2(0xc0010015)
 114 #define RNDIS_STATUS_NOT_SUPPORTED      ccpu2(0xc00000bb)
 115 #define RNDIS_STATUS_MEDIA_CONNECT      ccpu2(0x4001000b)
 116 #define RNDIS_STATUS_MEDIA_DISCONNECT   ccpu2(0x4001000c)
 117
 118
 119 struct rndis_data_hdr {
 120         __le32  msg_type;               /* RNDIS_MSG_PACKET */
 121         __le32  msg_len;                // rndis_data_hdr + data_len + pad
 122         __le32  data_offset;            // 36 -- right after header
 123         __le32  data_len;               // ... real packet size
 124
 125         __le32  oob_data_offset;        // zero
 126         __le32  oob_data_len;           // zero
 127         __le32  num_oob;                // zero
 128         __le32  packet_data_offset;     // zero
 129
 130         __le32  packet_data_len;        // zero
 131         __le32  vc_handle;              // zero
 132         __le32  reserved;               // zero
 133 } __attribute__ ((packed));
 134
 135 struct rndis_init {             /* OUT */
 136         // header and:
 137         __le32  msg_type;                       /* RNDIS_MSG_INIT */
 138         __le32  msg_len;                        // 24
 139         __le32  request_id;
 140         __le32  major_version;                  // of rndis (1.0)
 141         __le32  minor_version;
 142         __le32  max_transfer_size;
 143 } __attribute__ ((packed));
 144
 145 struct rndis_init_c {           /* IN */
 146         // header and:
 147         __le32  msg_type;                       /* RNDIS_MSG_INIT_C */
 148         __le32  msg_len;
 149         __le32  request_id;
 150         __le32  status;
 151         __le32  major_version;                  // of rndis (1.0)
 152         __le32  minor_version;
 153         __le32  device_flags;
 154         __le32  medium;                         // zero == 802.3
 155         __le32  max_packets_per_message;
 156         __le32  max_transfer_size;
 157         __le32  packet_alignment;               // max 7; (1<<n) bytes
 158         __le32  af_list_offset;                 // zero
 159         __le32  af_list_size;                   // zero
 160 } __attribute__ ((packed));
 161
 162 struct rndis_halt {             /* OUT (no reply) */
 163         // header and:
 164         __le32  msg_type;                       /* RNDIS_MSG_HALT */
 165         __le32  msg_len;
 166         __le32  request_id;
 167 } __attribute__ ((packed));
 168
 169 struct rndis_query {            /* OUT */
 170         // header and:
 171         __le32  msg_type;                       /* RNDIS_MSG_QUERY */
 172         __le32  msg_len;
 173         __le32  request_id;
 174         __le32  oid;
 175         __le32  len;
 176         __le32  offset;
 177 /*?*/   __le32  handle;                         // zero
 178 } __attribute__ ((packed));
 179
 180 struct rndis_query_c {          /* IN */
 181         // header and:
 182         __le32  msg_type;                       /* RNDIS_MSG_QUERY_C */
 183         __le32  msg_len;
 184         __le32  request_id;
 185         __le32  status;
 186         __le32  len;
 187         __le32  offset;
 188 } __attribute__ ((packed));
 189
 190 struct rndis_set {              /* OUT */
 191         // header and:
 192         __le32  msg_type;                       /* RNDIS_MSG_SET */
 193         __le32  msg_len;
 194         __le32  request_id;
 195         __le32  oid;
 196         __le32  len;
 197         __le32  offset;
 198 /*?*/   __le32  handle;                         // zero
 199 } __attribute__ ((packed));
 200
 201 struct rndis_set_c {            /* IN */
 202         // header and:
 203         __le32  msg_type;                       /* RNDIS_MSG_SET_C */
 204         __le32  msg_len;
 205         __le32  request_id;
 206         __le32  status;
 207 } __attribute__ ((packed));
 208
 209 struct rndis_reset {            /* IN */
 210         // header and:
 211         __le32  msg_type;                       /* RNDIS_MSG_RESET */
 212         __le32  msg_len;
 213         __le32  reserved;
 214 } __attribute__ ((packed));
 215
 216 struct rndis_reset_c {          /* OUT */
 217         // header and:
 218         __le32  msg_type;                       /* RNDIS_MSG_RESET_C */
 219         __le32  msg_len;
 220         __le32  status;
 221         __le32  addressing_lost;
 222 } __attribute__ ((packed));
 223
 224 struct rndis_indicate {         /* IN (unrequested) */
 225         // header and:
 226         __le32  msg_type;                       /* RNDIS_MSG_INDICATE */
 227         __le32  msg_len;
 228         __le32  status;
 229         __le32  length;
 230         __le32  offset;
 231 /**/    __le32  diag_status;
 232         __le32  error_offset;
 233 /**/    __le32  message;
 234 } __attribute__ ((packed));
 235
 236 struct rndis_keepalive {        /* OUT (optionally IN) */
 237         // header and:
 238         __le32  msg_type;                       /* RNDIS_MSG_KEEPALIVE */
 239         __le32  msg_len;
 240         __le32  request_id;
 241 } __attribute__ ((packed));
 242
 243 struct rndis_keepalive_c {      /* IN (optionally OUT) */
 244         // header and:
 245         __le32  msg_type;                       /* RNDIS_MSG_KEEPALIVE_C */
 246         __le32  msg_len;
 247         __le32  request_id;
 248         __le32  status;
 249 } __attribute__ ((packed));
 250
 251 /* NOTE:  about 30 OIDs are "mandatory" for peripherals to support ... and
 252  * there are gobs more that may optionally be supported.  We'll avoid as much
 253  * of that mess as possible.
 254  */
 255 #define OID_802_3_PERMANENT_ADDRESS     ccpu2(0x01010101)
 256 #define OID_GEN_MAXIMUM_FRAME_SIZE      ccpu2(0x00010106)
 257 #define OID_GEN_CURRENT_PACKET_FILTER   ccpu2(0x0001010e)
 258
 259 /*
 260  * RNDIS notifications from device: command completion; "reverse"
 261  * keepalives; etc
 262  */
 263 static void rndis_status(struct usbnet *dev, struct urb *urb)
 264 {
 265         devdbg(dev, "rndis status urb, len %d stat %d",
 266                 urb->actual_length, urb->status);
 267         // FIXME for keepalives, respond immediately (asynchronously)
 268         // if not an RNDIS status, do like cdc_status(dev,urb) does
 269 }
 270
 271 /*
 272  * RPC done RNDIS-style.  Caller guarantees:
 273  * - message is properly byteswapped
 274  * - there's no other request pending
 275  * - buf can hold up to 1KB response (required by RNDIS spec)
 276  * On return, the first few entries are already byteswapped.
 277  *
 278  * Call context is likely probe(), before interface name is known,
 279  * which is why we won't try to use it in the diagnostics.
 280  */
 281 static int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf)
 282 {
 283         struct cdc_state        *info = (void *) &dev->data;
 284         int                     master_ifnum;
 285         int                     retval;
 286         unsigned                count;
 287         __le32                  rsp;
 288         u32                     xid = 0, msg_len, request_id;
 289
 290         /* REVISIT when this gets called from contexts other than probe() or
 291          * disconnect(): either serialize, or dispatch responses on xid
 292          */
 293
 294         /* Issue the request; xid is unique, don't bother byteswapping it */
 295         if (likely(buf->msg_type != RNDIS_MSG_HALT
 296                         && buf->msg_type != RNDIS_MSG_RESET)) {
 297                 xid = dev->xid++;
 298                 if (!xid)
 299                         xid = dev->xid++;
 300                 buf->request_id = (__force __le32) xid;
 301         }
 302         master_ifnum = info->control->cur_altsetting->desc.bInterfaceNumber;
 303         retval = usb_control_msg(dev->udev,
 304                 usb_sndctrlpipe(dev->udev, 0),
 305                 USB_CDC_SEND_ENCAPSULATED_COMMAND,
 306                 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 307                 0, master_ifnum,
 308                 buf, le32_to_cpu(buf->msg_len),
 309                 RNDIS_CONTROL_TIMEOUT_MS);
 310         if (unlikely(retval < 0 || xid == 0))
 311                 return retval;
 312
 313         // FIXME Seems like some devices discard responses when
 314         // we time out and cancel our "get response" requests...
 315         // so, this is fragile.  Probably need to poll for status.
 316
 317         /* ignore status endpoint, just poll the control channel;
 318          * the request probably completed immediately
 319          */
 320         rsp = buf->msg_type | RNDIS_MSG_COMPLETION;
 321         for (count = 0; count < 10; count++) {
 322                 memset(buf, 0, CONTROL_BUFFER_SIZE);
 323                 retval = usb_control_msg(dev->udev,
 324                         usb_rcvctrlpipe(dev->udev, 0),
 325                         USB_CDC_GET_ENCAPSULATED_RESPONSE,
 326                         USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 327                         0, master_ifnum,
 328                         buf, CONTROL_BUFFER_SIZE,
 329                         RNDIS_CONTROL_TIMEOUT_MS);
 330                 if (likely(retval >= 8)) {
 331                         msg_len = le32_to_cpu(buf->msg_len);
 332                         request_id = (__force u32) buf->request_id;
 333                         if (likely(buf->msg_type == rsp)) {
 334                                 if (likely(request_id == xid)) {
 335                                         if (unlikely(rsp == RNDIS_MSG_RESET_C))
 336                                                 return 0;
 337                                         if (likely(RNDIS_STATUS_SUCCESS
 338                                                         == buf->status))
 339                                                 return 0;
 340                                         dev_dbg(&info->control->dev,
 341                                                 "rndis reply status %08x\n",
 342                                                 le32_to_cpu(buf->status));
 343                                         return -EL3RST;
 344                                 }
 345                                 dev_dbg(&info->control->dev,
 346                                         "rndis reply id %d expected %d\n",
 347                                         request_id, xid);
 348                                 /* then likely retry */
 349                         } else switch (buf->msg_type) {
 350                         case RNDIS_MSG_INDICATE: {      /* fault */
 351                                 // struct rndis_indicate *msg = (void *)buf;
 352                                 dev_info(&info->control->dev,
 353                                         "rndis fault indication\n");
 354                                 }
 355                                 break;
 356                         case RNDIS_MSG_KEEPALIVE: {     /* ping */
 357                                 struct rndis_keepalive_c *msg = (void *)buf;
 358
 359                                 msg->msg_type = RNDIS_MSG_KEEPALIVE_C;
 360                                 msg->msg_len = ccpu2(sizeof *msg);
 361                                 msg->status = RNDIS_STATUS_SUCCESS;
 362                                 retval = usb_control_msg(dev->udev,
 363                                         usb_sndctrlpipe(dev->udev, 0),
 364                                         USB_CDC_SEND_ENCAPSULATED_COMMAND,
 365                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 366                                         0, master_ifnum,
 367                                         msg, sizeof *msg,
 368                                         RNDIS_CONTROL_TIMEOUT_MS);
 369                                 if (unlikely(retval < 0))
 370                                         dev_dbg(&info->control->dev,
 371                                                 "rndis keepalive err %d\n",
 372                                                 retval);
 373                                 }
 374                                 break;
 375                         default:
 376                                 dev_dbg(&info->control->dev,
 377                                         "unexpected rndis msg %08x len %d\n",
 378                                         le32_to_cpu(buf->msg_type), msg_len);
 379                         }
 380                 } else {
 381                         /* device probably issued a protocol stall; ignore */
 382                         dev_dbg(&info->control->dev,
 383                                 "rndis response error, code %d\n", retval);
 384                 }
 385                 msleep(2);
 386         }
 387         dev_dbg(&info->control->dev, "rndis response timeout\n");
 388         return -ETIMEDOUT;
 389 }
 390
 391 /*
 392  * rndis_query:
 393  *
 394  * Performs a query for @oid along with 0 or more bytes of payload as
 395  * specified by @in_len. If @reply_len is not set to -1 then the reply
 396  * length is checked against this value, resulting in an error if it
 397  * doesn't match.
 398  *
 399  * NOTE: Adding a payload exactly or greater than the size of the expected
 400  * response payload is an evident requirement MSFT added for ActiveSync.
 401  *
 402  * The only exception is for OIDs that return a variably sized response,
 403  * in which case no payload should be added.  This undocumented (and
 404  * nonsensical!) issue was found by sniffing protocol requests from the
 405  * ActiveSync 4.1 Windows driver.
 406  */
 407 static int rndis_query(struct usbnet *dev, struct usb_interface *intf,
 408                 void *buf, u32 oid, u32 in_len,
 409                 void **reply, int *reply_len)
 410 {
 411         int retval;
 412         union {
 413                 void                    *buf;
 414                 struct rndis_msg_hdr    *header;
 415                 struct rndis_query      *get;
 416                 struct rndis_query_c    *get_c;
 417         } u;
 418         u32 off, len;
 419
 420         u.buf = buf;
 421
 422         memset(u.get, 0, sizeof *u.get + in_len);
 423         u.get->msg_type = RNDIS_MSG_QUERY;
 424         u.get->msg_len = cpu_to_le32(sizeof *u.get + in_len);
 425         u.get->oid = oid;
 426         u.get->len = cpu_to_le32(in_len);
 427         u.get->offset = ccpu2(20);
 428
 429         retval = rndis_command(dev, u.header);
 430         if (unlikely(retval < 0)) {
 431                 dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) failed, %d\n",
 432                                 oid, retval);
 433                 return retval;
 434         }
 435
 436         off = le32_to_cpu(u.get_c->offset);
 437         len = le32_to_cpu(u.get_c->len);
 438         if (unlikely((8 + off + len) > CONTROL_BUFFER_SIZE))
 439                 goto response_error;
 440
 441         if (*reply_len != -1 && len != *reply_len)
 442                 goto response_error;
 443
 444         *reply = (unsigned char *) &u.get_c->request_id + off;
 445         *reply_len = len;
 446
 447         return retval;
 448
 449 response_error:
 450         dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) "
 451                         "invalid response - off %d len %d\n",
 452                 oid, off, len);
 453         return -EDOM;
 454 }
 455
 456 static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
 457 {
 458         int                     retval;
 459         struct net_device       *net = dev->net;
 460         struct cdc_state        *info = (void *) &dev->data;
 461         union {
 462                 void                    *buf;
 463                 struct rndis_msg_hdr    *header;
 464                 struct rndis_init       *init;
 465                 struct rndis_init_c     *init_c;
 466                 struct rndis_query      *get;
 467                 struct rndis_query_c    *get_c;
 468                 struct rndis_set        *set;
 469                 struct rndis_set_c      *set_c;
 470         } u;
 471         u32                     tmp;
 472         int                     reply_len;
 473         unsigned char           *bp;
 474
 475         /* we can't rely on i/o from stack working, or stack allocation */
 476         u.buf = kmalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 477         if (!u.buf)
 478                 return -ENOMEM;
 479         retval = usbnet_generic_cdc_bind(dev, intf);
 480         if (retval < 0)
 481                 goto fail;
 482
 483         u.init->msg_type = RNDIS_MSG_INIT;
 484         u.init->msg_len = ccpu2(sizeof *u.init);
 485         u.init->major_version = ccpu2(1);
 486         u.init->minor_version = ccpu2(0);
 487
 488         /* max transfer (in spec) is 0x4000 at full speed, but for
 489          * TX we'll stick to one Ethernet packet plus RNDIS framing.
 490          * For RX we handle drivers that zero-pad to end-of-packet.
 491          * Don't let userspace change these settings.
 492          *
 493          * NOTE: there still seems to be wierdness here, as if we need
 494          * to do some more things to make sure WinCE targets accept this.
 495          * They default to jumbograms of 8KB or 16KB, which is absurd
 496          * for such low data rates and which is also more than Linux
 497          * can usually expect to allocate for SKB data...
 498          */
 499         net->hard_header_len += sizeof (struct rndis_data_hdr);
 500         dev->hard_mtu = net->mtu + net->hard_header_len;
 501
 502         dev->rx_urb_size = dev->hard_mtu + (dev->maxpacket + 1);
 503         dev->rx_urb_size &= ~(dev->maxpacket - 1);
 504         u.init->max_transfer_size = cpu_to_le32(dev->rx_urb_size);
 505
 506         net->change_mtu = NULL;
 507         retval = rndis_command(dev, u.header);
 508         if (unlikely(retval < 0)) {
 509                 /* it might not even be an RNDIS device!! */
 510                 dev_err(&intf->dev, "RNDIS init failed, %d\n", retval);
 511                 goto fail_and_release;
 512         }
 513         tmp = le32_to_cpu(u.init_c->max_transfer_size);
 514         if (tmp < dev->hard_mtu) {
 515                 if (tmp <= net->hard_header_len) {
 516                         dev_err(&intf->dev,
 517                                 "dev can't take %u byte packets (max %u)\n",
 518                                 dev->hard_mtu, tmp);
 519                         retval = -EINVAL;
 520                         goto fail_and_release;
 521                 }
 522                 dev->hard_mtu = tmp;
 523                 net->mtu = dev->hard_mtu - net->hard_header_len;
 524                 dev_warn(&intf->dev,
 525                          "dev can't take %u byte packets (max %u), "
 526                          "adjusting MTU to %u\n",
 527                          dev->hard_mtu, tmp, net->mtu);
 528         }
 529
 530         /* REVISIT:  peripheral "alignment" request is ignored ... */
 531         dev_dbg(&intf->dev,
 532                 "hard mtu %u (%u from dev), rx buflen %Zu, align %d\n",
 533                 dev->hard_mtu, tmp, dev->rx_urb_size,
 534                 1 << le32_to_cpu(u.init_c->packet_alignment));
 535
 536         /* Get designated host ethernet address */
 537         reply_len = ETH_ALEN;
 538         retval = rndis_query(dev, intf, u.buf, OID_802_3_PERMANENT_ADDRESS,
 539                         48, (void **) &bp, &reply_len);
 540         if (unlikely(retval< 0)) {
 541                 dev_err(&intf->dev, "rndis get ethaddr, %d\n", retval);
 542                 goto fail_and_release;
 543         }
 544         memcpy(net->dev_addr, bp, ETH_ALEN);
 545
 546         /* set a nonzero filter to enable data transfers */
 547         memset(u.set, 0, sizeof *u.set);
 548         u.set->msg_type = RNDIS_MSG_SET;
 549         u.set->msg_len = ccpu2(4 + sizeof *u.set);
 550         u.set->oid = OID_GEN_CURRENT_PACKET_FILTER;
 551         u.set->len = ccpu2(4);
 552         u.set->offset = ccpu2((sizeof *u.set) - 8);
 553         *(__le32 *)(u.buf + sizeof *u.set) = ccpu2(DEFAULT_FILTER);
 554
 555         retval = rndis_command(dev, u.header);
 556         if (unlikely(retval < 0)) {
 557                 dev_err(&intf->dev, "rndis set packet filter, %d\n", retval);
 558                 goto fail_and_release;
 559         }
 560
 561         retval = 0;
 562
 563         kfree(u.buf);
 564         return retval;
 565
 566 fail_and_release:
 567         usb_set_intfdata(info->data, NULL);
 568         usb_driver_release_interface(driver_of(intf), info->data);
 569         info->data = NULL;
 570 fail:
 571         kfree(u.buf);
 572         return retval;
 573 }
 574
 575 static void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
 576 {
 577         struct rndis_halt       *halt;
 578
 579         /* try to clear any rndis state/activity (no i/o from stack!) */
 580         halt = kzalloc(sizeof *halt, GFP_KERNEL);
 581         if (halt) {
 582                 halt->msg_type = RNDIS_MSG_HALT;
 583                 halt->msg_len = ccpu2(sizeof *halt);
 584                 (void) rndis_command(dev, (void *)halt);
 585                 kfree(halt);
 586         }
 587
 588         return usbnet_cdc_unbind(dev, intf);
 589 }
 590
 591 /*
 592  * DATA -- host must not write zlps
 593  */
 594 static int rndis_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 595 {
 596         /* peripheral may have batched packets to us... */
 597         while (likely(skb->len)) {
 598                 struct rndis_data_hdr   *hdr = (void *)skb->data;
 599                 struct sk_buff          *skb2;
 600                 u32                     msg_len, data_offset, data_len;
 601
 602                 msg_len = le32_to_cpu(hdr->msg_len);
 603                 data_offset = le32_to_cpu(hdr->data_offset);
 604                 data_len = le32_to_cpu(hdr->data_len);
 605
 606                 /* don't choke if we see oob, per-packet data, etc */
 607                 if (unlikely(hdr->msg_type != RNDIS_MSG_PACKET
 608                                 || skb->len < msg_len
 609                                 || (data_offset + data_len + 8) > msg_len)) {
 610                         dev->stats.rx_frame_errors++;
 611                         devdbg(dev, "bad rndis message %d/%d/%d/%d, len %d",
 612                                 le32_to_cpu(hdr->msg_type),
 613                                 msg_len, data_offset, data_len, skb->len);
 614                         return 0;
 615                 }
 616                 skb_pull(skb, 8 + data_offset);
 617
 618                 /* at most one packet left? */
 619                 if (likely((data_len - skb->len) <= sizeof *hdr)) {
 620                         skb_trim(skb, data_len);
 621                         break;
 622                 }
 623
 624                 /* try to return all the packets in the batch */
 625                 skb2 = skb_clone(skb, GFP_ATOMIC);
 626                 if (unlikely(!skb2))
 627                         break;
 628                 skb_pull(skb, msg_len - sizeof *hdr);
 629                 skb_trim(skb2, data_len);
 630                 usbnet_skb_return(dev, skb2);
 631         }
 632
 633         /* caller will usbnet_skb_return the remaining packet */
 634         return 1;
 635 }
 636
 637 static struct sk_buff *
 638 rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 639 {
 640         struct rndis_data_hdr   *hdr;
 641         struct sk_buff          *skb2;
 642         unsigned                len = skb->len;
 643
 644         if (likely(!skb_cloned(skb))) {
 645                 int     room = skb_headroom(skb);
 646
 647                 /* enough head room as-is? */
 648                 if (unlikely((sizeof *hdr) <= room))
 649                         goto fill;
 650
 651                 /* enough room, but needs to be readjusted? */
 652                 room += skb_tailroom(skb);
 653                 if (likely((sizeof *hdr) <= room)) {
 654                         skb->data = memmove(skb->head + sizeof *hdr,
 655                                             skb->data, len);
 656                         skb_set_tail_pointer(skb, len);
 657                         goto fill;
 658                 }
 659         }
 660
 661         /* create a new skb, with the correct size (and tailpad) */
 662         skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
 663         dev_kfree_skb_any(skb);
 664         if (unlikely(!skb2))
 665                 return skb2;
 666         skb = skb2;
 667
 668         /* fill out the RNDIS header.  we won't bother trying to batch
 669          * packets; Linux minimizes wasted bandwidth through tx queues.
 670          */
 671 fill:
 672         hdr = (void *) __skb_push(skb, sizeof *hdr);
 673         memset(hdr, 0, sizeof *hdr);
 674         hdr->msg_type = RNDIS_MSG_PACKET;
 675         hdr->msg_len = cpu_to_le32(skb->len);
 676         hdr->data_offset = ccpu2(sizeof(*hdr) - 8);
 677         hdr->data_len = cpu_to_le32(len);
 678
 679         /* FIXME make the last packet always be short ... */
 680         return skb;
 681 }
 682
 683
 684 static const struct driver_info rndis_info = {
 685         .description =  "RNDIS device",
 686         .flags =        FLAG_ETHER | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 687         .bind =         rndis_bind,
 688         .unbind =       rndis_unbind,
 689         .status =       rndis_status,
 690         .rx_fixup =     rndis_rx_fixup,
 691         .tx_fixup =     rndis_tx_fixup,
 692 };
 693
 694 #undef ccpu2
 695
 696
 697 /*-------------------------------------------------------------------------*/
 698
 699 static const struct usb_device_id       products [] = {
 700 {
 701         /* RNDIS is MSFT's un-official variant of CDC ACM */
 702         USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
 703         .driver_info = (unsigned long) &rndis_info,
 704 }, {
 705         /* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
 706         USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
 707         .driver_info = (unsigned long) &rndis_info,
 708 },
 709         { },            // END
 710 };
 711 MODULE_DEVICE_TABLE(usb, products);
 712
 713 static struct usb_driver rndis_driver = {
 714         .name =         "rndis_host",
 715         .id_table =     products,
 716         .probe =        usbnet_probe,
 717         .disconnect =   usbnet_disconnect,
 718         .suspend =      usbnet_suspend,
 719         .resume =       usbnet_resume,
 720 };
 721
 722 static int __init rndis_init(void)
 723 {
 724         return usb_register(&rndis_driver);
 725 }
 726 module_init(rndis_init);
 727
 728 static void __exit rndis_exit(void)
 729 {
 730         usb_deregister(&rndis_driver);
 731 }
 732 module_exit(rndis_exit);
 733
 734 MODULE_AUTHOR("David Brownell");
 735 MODULE_DESCRIPTION("USB Host side RNDIS driver");
 736 MODULE_LICENSE("GPL");