drivers/usb/net/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/config.h>
  24 #include <linux/module.h>
  25 #include <linux/sched.h>
  26 #include <linux/init.h>
  27 #include <linux/netdevice.h>
  28 #include <linux/etherdevice.h>
  29 #include <linux/ethtool.h>
  30 #include <linux/workqueue.h>
  31 #include <linux/mii.h>
  32 #include <linux/usb.h>
  33 #include <linux/usb/cdc.h>
  34
  35 #include "usbnet.h"
  36
  37
  38 /*
  39  * RNDIS is NDIS remoted over USB.  It's a MSFT variant of CDC ACM ... of
  40  * course ACM was intended for modems, not Ethernet links!  USB's standard
  41  * for Ethernet links is "CDC Ethernet", which is significantly simpler.
  42  *
  43  * NOTE that Microsoft's "RNDIS 1.0" specification is incomplete.  Issues
  44  * include:
  45  *    - Power management in particular relies on information that's scattered
  46  *      through other documentation, and which is incomplete or incorrect even
  47  *      there.
  48  *    - There are various undocumented protocol requirements, such as the
  49  *      need to send unused garbage in control-OUT messages.
  50  *    - In some cases, MS-Windows will emit undocumented requests; this
  51  *      matters more to peripheral implementations than host ones.
  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 struct rndis_msg_hdr {
  67         __le32  msg_type;                       /* RNDIS_MSG_* */
  68         __le32  msg_len;
  69         // followed by data that varies between messages
  70         __le32  request_id;
  71         __le32  status;
  72         // ... and more
  73 } __attribute__ ((packed));
  74
  75 /* RNDIS defines this (absurdly huge) control timeout */
  76 #define RNDIS_CONTROL_TIMEOUT_MS        (10 * 1000)
  77
  78
  79 #define ccpu2 __constant_cpu_to_le32
  80
  81 #define RNDIS_MSG_COMPLETION    ccpu2(0x80000000)
  82
  83 /* codes for "msg_type" field of rndis messages;
  84  * only the data channel uses packet messages (maybe batched);
  85  * everything else goes on the control channel.
  86  */
  87 #define RNDIS_MSG_PACKET        ccpu2(0x00000001)       /* 1-N packets */
  88 #define RNDIS_MSG_INIT          ccpu2(0x00000002)
  89 #define RNDIS_MSG_INIT_C        (RNDIS_MSG_INIT|RNDIS_MSG_COMPLETION)
  90 #define RNDIS_MSG_HALT          ccpu2(0x00000003)
  91 #define RNDIS_MSG_QUERY         ccpu2(0x00000004)
  92 #define RNDIS_MSG_QUERY_C       (RNDIS_MSG_QUERY|RNDIS_MSG_COMPLETION)
  93 #define RNDIS_MSG_SET           ccpu2(0x00000005)
  94 #define RNDIS_MSG_SET_C         (RNDIS_MSG_SET|RNDIS_MSG_COMPLETION)
  95 #define RNDIS_MSG_RESET         ccpu2(0x00000006)
  96 #define RNDIS_MSG_RESET_C       (RNDIS_MSG_RESET|RNDIS_MSG_COMPLETION)
  97 #define RNDIS_MSG_INDICATE      ccpu2(0x00000007)
  98 #define RNDIS_MSG_KEEPALIVE     ccpu2(0x00000008)
  99 #define RNDIS_MSG_KEEPALIVE_C   (RNDIS_MSG_KEEPALIVE|RNDIS_MSG_COMPLETION)
 100
 101 /* codes for "status" field of completion messages */
 102 #define RNDIS_STATUS_SUCCESS            ccpu2(0x00000000)
 103 #define RNDIS_STATUS_FAILURE            ccpu2(0xc0000001)
 104 #define RNDIS_STATUS_INVALID_DATA       ccpu2(0xc0010015)
 105 #define RNDIS_STATUS_NOT_SUPPORTED      ccpu2(0xc00000bb)
 106 #define RNDIS_STATUS_MEDIA_CONNECT      ccpu2(0x4001000b)
 107 #define RNDIS_STATUS_MEDIA_DISCONNECT   ccpu2(0x4001000c)
 108
 109
 110 struct rndis_data_hdr {
 111         __le32  msg_type;               /* RNDIS_MSG_PACKET */
 112         __le32  msg_len;                // rndis_data_hdr + data_len + pad
 113         __le32  data_offset;            // 36 -- right after header
 114         __le32  data_len;               // ... real packet size
 115
 116         __le32  oob_data_offset;        // zero
 117         __le32  oob_data_len;           // zero
 118         __le32  num_oob;                // zero
 119         __le32  packet_data_offset;     // zero
 120
 121         __le32  packet_data_len;        // zero
 122         __le32  vc_handle;              // zero
 123         __le32  reserved;               // zero
 124 } __attribute__ ((packed));
 125
 126 struct rndis_init {             /* OUT */
 127         // header and:
 128         __le32  msg_type;                       /* RNDIS_MSG_INIT */
 129         __le32  msg_len;                        // 24
 130         __le32  request_id;
 131         __le32  major_version;                  // of rndis (1.0)
 132         __le32  minor_version;
 133         __le32  max_transfer_size;
 134 } __attribute__ ((packed));
 135
 136 struct rndis_init_c {           /* IN */
 137         // header and:
 138         __le32  msg_type;                       /* RNDIS_MSG_INIT_C */
 139         __le32  msg_len;
 140         __le32  request_id;
 141         __le32  status;
 142         __le32  major_version;                  // of rndis (1.0)
 143         __le32  minor_version;
 144         __le32  device_flags;
 145         __le32  medium;                         // zero == 802.3
 146         __le32  max_packets_per_message;
 147         __le32  max_transfer_size;
 148         __le32  packet_alignment;               // max 7; (1<<n) bytes
 149         __le32  af_list_offset;                 // zero
 150         __le32  af_list_size;                   // zero
 151 } __attribute__ ((packed));
 152
 153 struct rndis_halt {             /* OUT (no reply) */
 154         // header and:
 155         __le32  msg_type;                       /* RNDIS_MSG_HALT */
 156         __le32  msg_len;
 157         __le32  request_id;
 158 } __attribute__ ((packed));
 159
 160 struct rndis_query {            /* OUT */
 161         // header and:
 162         __le32  msg_type;                       /* RNDIS_MSG_QUERY */
 163         __le32  msg_len;
 164         __le32  request_id;
 165         __le32  oid;
 166         __le32  len;
 167         __le32  offset;
 168 /*?*/   __le32  handle;                         // zero
 169 } __attribute__ ((packed));
 170
 171 struct rndis_query_c {          /* IN */
 172         // header and:
 173         __le32  msg_type;                       /* RNDIS_MSG_QUERY_C */
 174         __le32  msg_len;
 175         __le32  request_id;
 176         __le32  status;
 177         __le32  len;
 178         __le32  offset;
 179 } __attribute__ ((packed));
 180
 181 struct rndis_set {              /* OUT */
 182         // header and:
 183         __le32  msg_type;                       /* RNDIS_MSG_SET */
 184         __le32  msg_len;
 185         __le32  request_id;
 186         __le32  oid;
 187         __le32  len;
 188         __le32  offset;
 189 /*?*/   __le32  handle;                         // zero
 190 } __attribute__ ((packed));
 191
 192 struct rndis_set_c {            /* IN */
 193         // header and:
 194         __le32  msg_type;                       /* RNDIS_MSG_SET_C */
 195         __le32  msg_len;
 196         __le32  request_id;
 197         __le32  status;
 198 } __attribute__ ((packed));
 199
 200 struct rndis_reset {            /* IN */
 201         // header and:
 202         __le32  msg_type;                       /* RNDIS_MSG_RESET */
 203         __le32  msg_len;
 204         __le32  reserved;
 205 } __attribute__ ((packed));
 206
 207 struct rndis_reset_c {          /* OUT */
 208         // header and:
 209         __le32  msg_type;                       /* RNDIS_MSG_RESET_C */
 210         __le32  msg_len;
 211         __le32  status;
 212         __le32  addressing_lost;
 213 } __attribute__ ((packed));
 214
 215 struct rndis_indicate {         /* IN (unrequested) */
 216         // header and:
 217         __le32  msg_type;                       /* RNDIS_MSG_INDICATE */
 218         __le32  msg_len;
 219         __le32  status;
 220         __le32  length;
 221         __le32  offset;
 222 /**/    __le32  diag_status;
 223         __le32  error_offset;
 224 /**/    __le32  message;
 225 } __attribute__ ((packed));
 226
 227 struct rndis_keepalive {        /* OUT (optionally IN) */
 228         // header and:
 229         __le32  msg_type;                       /* RNDIS_MSG_KEEPALIVE */
 230         __le32  msg_len;
 231         __le32  request_id;
 232 } __attribute__ ((packed));
 233
 234 struct rndis_keepalive_c {      /* IN (optionally OUT) */
 235         // header and:
 236         __le32  msg_type;                       /* RNDIS_MSG_KEEPALIVE_C */
 237         __le32  msg_len;
 238         __le32  request_id;
 239         __le32  status;
 240 } __attribute__ ((packed));
 241
 242 /* NOTE:  about 30 OIDs are "mandatory" for peripherals to support ... and
 243  * there are gobs more that may optionally be supported.  We'll avoid as much
 244  * of that mess as possible.
 245  */
 246 #define OID_802_3_PERMANENT_ADDRESS     ccpu2(0x01010101)
 247 #define OID_GEN_CURRENT_PACKET_FILTER   ccpu2(0x0001010e)
 248
 249 /*
 250  * RNDIS notifications from device: command completion; "reverse"
 251  * keepalives; etc
 252  */
 253 static void rndis_status(struct usbnet *dev, struct urb *urb)
 254 {
 255         devdbg(dev, "rndis status urb, len %d stat %d",
 256                 urb->actual_length, urb->status);
 257         // FIXME for keepalives, respond immediately (asynchronously)
 258         // if not an RNDIS status, do like cdc_status(dev,urb) does
 259 }
 260
 261 /*
 262  * RPC done RNDIS-style.  Caller guarantees:
 263  * - message is properly byteswapped
 264  * - there's no other request pending
 265  * - buf can hold up to 1KB response (required by RNDIS spec)
 266  * On return, the first few entries are already byteswapped.
 267  *
 268  * Call context is likely probe(), before interface name is known,
 269  * which is why we won't try to use it in the diagnostics.
 270  */
 271 static int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf)
 272 {
 273         struct cdc_state        *info = (void *) &dev->data;
 274         int                     retval;
 275         unsigned                count;
 276         __le32                  rsp;
 277         u32                     xid = 0, msg_len, request_id;
 278
 279         /* REVISIT when this gets called from contexts other than probe() or
 280          * disconnect(): either serialize, or dispatch responses on xid
 281          */
 282
 283         /* Issue the request; don't bother byteswapping our xid */
 284         if (likely(buf->msg_type != RNDIS_MSG_HALT
 285                         && buf->msg_type != RNDIS_MSG_RESET)) {
 286                 xid = dev->xid++;
 287                 if (!xid)
 288                         xid = dev->xid++;
 289                 buf->request_id = (__force __le32) xid;
 290         }
 291         retval = usb_control_msg(dev->udev,
 292                 usb_sndctrlpipe(dev->udev, 0),
 293                 USB_CDC_SEND_ENCAPSULATED_COMMAND,
 294                 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 295                 0, info->u->bMasterInterface0,
 296                 buf, le32_to_cpu(buf->msg_len),
 297                 RNDIS_CONTROL_TIMEOUT_MS);
 298         if (unlikely(retval < 0 || xid == 0))
 299                 return retval;
 300
 301         // FIXME Seems like some devices discard responses when
 302         // we time out and cancel our "get response" requests...
 303         // so, this is fragile.  Probably need to poll for status.
 304
 305         /* ignore status endpoint, just poll the control channel;
 306          * the request probably completed immediately
 307          */
 308         rsp = buf->msg_type | RNDIS_MSG_COMPLETION;
 309         for (count = 0; count < 10; count++) {
 310                 memset(buf, 0, 1024);
 311                 retval = usb_control_msg(dev->udev,
 312                         usb_rcvctrlpipe(dev->udev, 0),
 313                         USB_CDC_GET_ENCAPSULATED_RESPONSE,
 314                         USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 315                         0, info->u->bMasterInterface0,
 316                         buf, 1024,
 317                         RNDIS_CONTROL_TIMEOUT_MS);
 318                 if (likely(retval >= 8)) {
 319                         msg_len = le32_to_cpu(buf->msg_len);
 320                         request_id = (__force u32) buf->request_id;
 321                         if (likely(buf->msg_type == rsp)) {
 322                                 if (likely(request_id == xid)) {
 323                                         if (unlikely(rsp == RNDIS_MSG_RESET_C))
 324                                                 return 0;
 325                                         if (likely(RNDIS_STATUS_SUCCESS
 326                                                         == buf->status))
 327                                                 return 0;
 328                                         dev_dbg(&info->control->dev,
 329                                                 "rndis reply status %08x\n",
 330                                                 le32_to_cpu(buf->status));
 331                                         return -EL3RST;
 332                                 }
 333                                 dev_dbg(&info->control->dev,
 334                                         "rndis reply id %d expected %d\n",
 335                                         request_id, xid);
 336                                 /* then likely retry */
 337                         } else switch (buf->msg_type) {
 338                         case RNDIS_MSG_INDICATE: {      /* fault */
 339                                 // struct rndis_indicate *msg = (void *)buf;
 340                                 dev_info(&info->control->dev,
 341                                          "rndis fault indication\n");
 342                                 }
 343                                 break;
 344                         case RNDIS_MSG_KEEPALIVE: {     /* ping */
 345                                 struct rndis_keepalive_c *msg = (void *)buf;
 346
 347                                 msg->msg_type = RNDIS_MSG_KEEPALIVE_C;
 348                                 msg->msg_len = ccpu2(sizeof *msg);
 349                                 msg->status = RNDIS_STATUS_SUCCESS;
 350                                 retval = usb_control_msg(dev->udev,
 351                                         usb_sndctrlpipe(dev->udev, 0),
 352                                         USB_CDC_SEND_ENCAPSULATED_COMMAND,
 353                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 354                                         0, info->u->bMasterInterface0,
 355                                         msg, sizeof *msg,
 356                                         RNDIS_CONTROL_TIMEOUT_MS);
 357                                 if (unlikely(retval < 0))
 358                                         dev_dbg(&info->control->dev,
 359                                                 "rndis keepalive err %d\n",
 360                                                 retval);
 361                                 }
 362                                 break;
 363                         default:
 364                                 dev_dbg(&info->control->dev,
 365                                         "unexpected rndis msg %08x len %d\n",
 366                                         le32_to_cpu(buf->msg_type), msg_len);
 367                         }
 368                 } else {
 369                         /* device probably issued a protocol stall; ignore */
 370                         dev_dbg(&info->control->dev,
 371                                 "rndis response error, code %d\n", retval);
 372                 }
 373                 msleep(2);
 374         }
 375         dev_dbg(&info->control->dev, "rndis response timeout\n");
 376         return -ETIMEDOUT;
 377 }
 378
 379 static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
 380 {
 381         int                     retval;
 382         struct net_device       *net = dev->net;
 383         union {
 384                 void                    *buf;
 385                 struct rndis_msg_hdr    *header;
 386                 struct rndis_init       *init;
 387                 struct rndis_init_c     *init_c;
 388                 struct rndis_query      *get;
 389                 struct rndis_query_c    *get_c;
 390                 struct rndis_set        *set;
 391                 struct rndis_set_c      *set_c;
 392         } u;
 393         u32                     tmp;
 394
 395         /* we can't rely on i/o from stack working, or stack allocation */
 396         u.buf = kmalloc(1024, GFP_KERNEL);
 397         if (!u.buf)
 398                 return -ENOMEM;
 399         retval = usbnet_generic_cdc_bind(dev, intf);
 400         if (retval < 0)
 401                 goto done;
 402
 403         net->hard_header_len += sizeof (struct rndis_data_hdr);
 404
 405         /* initialize; max transfer is 16KB at full speed */
 406         u.init->msg_type = RNDIS_MSG_INIT;
 407         u.init->msg_len = ccpu2(sizeof *u.init);
 408         u.init->major_version = ccpu2(1);
 409         u.init->minor_version = ccpu2(0);
 410         u.init->max_transfer_size = ccpu2(net->mtu + net->hard_header_len);
 411
 412         retval = rndis_command(dev, u.header);
 413         if (unlikely(retval < 0)) {
 414                 /* it might not even be an RNDIS device!! */
 415                 dev_err(&intf->dev, "RNDIS init failed, %d\n", retval);
 416 fail:
 417                 usb_driver_release_interface(driver_of(intf),
 418                         ((struct cdc_state *)&(dev->data))->data);
 419                 goto done;
 420         }
 421         dev->hard_mtu = le32_to_cpu(u.init_c->max_transfer_size);
 422         /* REVISIT:  peripheral "alignment" request is ignored ... */
 423         dev_dbg(&intf->dev, "hard mtu %u, align %d\n", dev->hard_mtu,
 424                 1 << le32_to_cpu(u.init_c->packet_alignment));
 425
 426         /* get designated host ethernet address */
 427         memset(u.get, 0, sizeof *u.get);
 428         u.get->msg_type = RNDIS_MSG_QUERY;
 429         u.get->msg_len = ccpu2(sizeof *u.get);
 430         u.get->oid = OID_802_3_PERMANENT_ADDRESS;
 431
 432         retval = rndis_command(dev, u.header);
 433         if (unlikely(retval < 0)) {
 434                 dev_err(&intf->dev, "rndis get ethaddr, %d\n", retval);
 435                 goto fail;
 436         }
 437         tmp = le32_to_cpu(u.get_c->offset);
 438         if (unlikely((tmp + 8) > (1024 - ETH_ALEN)
 439                         || u.get_c->len != ccpu2(ETH_ALEN))) {
 440                 dev_err(&intf->dev, "rndis ethaddr off %d len %d ?\n",
 441                         tmp, le32_to_cpu(u.get_c->len));
 442                 retval = -EDOM;
 443                 goto fail;
 444         }
 445         memcpy(net->dev_addr, tmp + (char *)&u.get_c->request_id, ETH_ALEN);
 446
 447         /* set a nonzero filter to enable data transfers */
 448         memset(u.set, 0, sizeof *u.set);
 449         u.set->msg_type = RNDIS_MSG_SET;
 450         u.set->msg_len = ccpu2(4 + sizeof *u.set);
 451         u.set->oid = OID_GEN_CURRENT_PACKET_FILTER;
 452         u.set->len = ccpu2(4);
 453         u.set->offset = ccpu2((sizeof *u.set) - 8);
 454         *(__le32 *)(u.buf + sizeof *u.set) = ccpu2(DEFAULT_FILTER);
 455
 456         retval = rndis_command(dev, u.header);
 457         if (unlikely(retval < 0)) {
 458                 dev_err(&intf->dev, "rndis set packet filter, %d\n", retval);
 459                 goto fail;
 460         }
 461
 462         retval = 0;
 463 done:
 464         kfree(u.buf);
 465         return retval;
 466 }
 467
 468 static void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
 469 {
 470         struct rndis_halt       *halt;
 471
 472         /* try to clear any rndis state/activity (no i/o from stack!) */
 473         halt = kcalloc(1, sizeof *halt, SLAB_KERNEL);
 474         if (halt) {
 475                 halt->msg_type = RNDIS_MSG_HALT;
 476                 halt->msg_len = ccpu2(sizeof *halt);
 477                 (void) rndis_command(dev, (void *)halt);
 478                 kfree(halt);
 479         }
 480
 481         return usbnet_cdc_unbind(dev, intf);
 482 }
 483
 484 /*
 485  * DATA -- host must not write zlps
 486  */
 487 static int rndis_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 488 {
 489         /* peripheral may have batched packets to us... */
 490         while (likely(skb->len)) {
 491                 struct rndis_data_hdr   *hdr = (void *)skb->data;
 492                 struct sk_buff          *skb2;
 493                 u32                     msg_len, data_offset, data_len;
 494
 495                 msg_len = le32_to_cpu(hdr->msg_len);
 496                 data_offset = le32_to_cpu(hdr->data_offset);
 497                 data_len = le32_to_cpu(hdr->data_len);
 498
 499                 /* don't choke if we see oob, per-packet data, etc */
 500                 if (unlikely(hdr->msg_type != RNDIS_MSG_PACKET
 501                                 || skb->len < msg_len
 502                                 || (data_offset + data_len + 8) > msg_len)) {
 503                         dev->stats.rx_frame_errors++;
 504                         devdbg(dev, "bad rndis message %d/%d/%d/%d, len %d",
 505                                 le32_to_cpu(hdr->msg_type),
 506                                 msg_len, data_offset, data_len, skb->len);
 507                         return 0;
 508                 }
 509                 skb_pull(skb, 8 + data_offset);
 510
 511                 /* at most one packet left? */
 512                 if (likely((data_len - skb->len) <= sizeof *hdr)) {
 513                         skb_trim(skb, data_len);
 514                         break;
 515                 }
 516
 517                 /* try to return all the packets in the batch */
 518                 skb2 = skb_clone(skb, GFP_ATOMIC);
 519                 if (unlikely(!skb2))
 520                         break;
 521                 skb_pull(skb, msg_len - sizeof *hdr);
 522                 skb_trim(skb2, data_len);
 523                 usbnet_skb_return(dev, skb2);
 524         }
 525
 526         /* caller will usbnet_skb_return the remaining packet */
 527         return 1;
 528 }
 529
 530 static struct sk_buff *
 531 rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 532 {
 533         struct rndis_data_hdr   *hdr;
 534         struct sk_buff          *skb2;
 535         unsigned                len = skb->len;
 536
 537         if (likely(!skb_cloned(skb))) {
 538                 int     room = skb_headroom(skb);
 539
 540                 /* enough head room as-is? */
 541                 if (unlikely((sizeof *hdr) <= room))
 542                         goto fill;
 543
 544                 /* enough room, but needs to be readjusted? */
 545                 room += skb_tailroom(skb);
 546                 if (likely((sizeof *hdr) <= room)) {
 547                         skb->data = memmove(skb->head + sizeof *hdr,
 548                                             skb->data, len);
 549                         skb->tail = skb->data + len;
 550                         goto fill;
 551                 }
 552         }
 553
 554         /* create a new skb, with the correct size (and tailpad) */
 555         skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
 556         dev_kfree_skb_any(skb);
 557         if (unlikely(!skb2))
 558                 return skb2;
 559         skb = skb2;
 560
 561         /* fill out the RNDIS header.  we won't bother trying to batch
 562          * packets; Linux minimizes wasted bandwidth through tx queues.
 563          */
 564 fill:
 565         hdr = (void *) __skb_push(skb, sizeof *hdr);
 566         memset(hdr, 0, sizeof *hdr);
 567         hdr->msg_type = RNDIS_MSG_PACKET;
 568         hdr->msg_len = cpu_to_le32(skb->len);
 569         hdr->data_offset = ccpu2(sizeof(*hdr) - 8);
 570         hdr->data_len = cpu_to_le32(len);
 571
 572         /* FIXME make the last packet always be short ... */
 573         return skb;
 574 }
 575
 576
 577 static const struct driver_info rndis_info = {
 578         .description =  "RNDIS device",
 579         .flags =        FLAG_ETHER | FLAG_FRAMING_RN,
 580         .bind =         rndis_bind,
 581         .unbind =       rndis_unbind,
 582         .status =       rndis_status,
 583         .rx_fixup =     rndis_rx_fixup,
 584         .tx_fixup =     rndis_tx_fixup,
 585 };
 586
 587 #undef ccpu2
 588
 589
 590 /*-------------------------------------------------------------------------*/
 591
 592 static const struct usb_device_id       products [] = {
 593 {
 594         /* RNDIS is MSFT's un-official variant of CDC ACM */
 595         USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
 596         .driver_info = (unsigned long) &rndis_info,
 597 },
 598         { },            // END
 599 };
 600 MODULE_DEVICE_TABLE(usb, products);
 601
 602 static struct usb_driver rndis_driver = {
 603         .name =         "rndis_host",
 604         .id_table =     products,
 605         .probe =        usbnet_probe,
 606         .disconnect =   usbnet_disconnect,
 607         .suspend =      usbnet_suspend,
 608         .resume =       usbnet_resume,
 609 };
 610
 611 static int __init rndis_init(void)
 612 {
 613         return usb_register(&rndis_driver);
 614 }
 615 module_init(rndis_init);
 616
 617 static void __exit rndis_exit(void)
 618 {
 619         usb_deregister(&rndis_driver);
 620 }
 621 module_exit(rndis_exit);
 622
 623 MODULE_AUTHOR("David Brownell");
 624 MODULE_DESCRIPTION("USB Host side RNDIS driver");
 625 MODULE_LICENSE("GPL");