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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
  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 #include "rndis_host.h"
  35
  36
  37 /*
  38  * RNDIS is NDIS remoted over USB.  It's a MSFT variant of CDC ACM ... of
  39  * course ACM was intended for modems, not Ethernet links!  USB's standard
  40  * for Ethernet links is "CDC Ethernet", which is significantly simpler.
  41  *
  42  * NOTE that Microsoft's "RNDIS 1.0" specification is incomplete.  Issues
  43  * include:
  44  *    - Power management in particular relies on information that's scattered
  45  *      through other documentation, and which is incomplete or incorrect even
  46  *      there.
  47  *    - There are various undocumented protocol requirements, such as the
  48  *      need to send unused garbage in control-OUT messages.
  49  *    - In some cases, MS-Windows will emit undocumented requests; this
  50  *      matters more to peripheral implementations than host ones.
  51  *
  52  * Moreover there's a no-open-specs variant of RNDIS called "ActiveSync".
  53  *
  54  * For these reasons and others, ** USE OF RNDIS IS STRONGLY DISCOURAGED ** in
  55  * favor of such non-proprietary alternatives as CDC Ethernet or the newer (and
  56  * currently rare) "Ethernet Emulation Model" (EEM).
  57  */
  58
  59 /*
  60  * RNDIS notifications from device: command completion; "reverse"
  61  * keepalives; etc
  62  */
  63 void rndis_status(struct usbnet *dev, struct urb *urb)
  64 {
  65         devdbg(dev, "rndis status urb, len %d stat %d",
  66                 urb->actual_length, urb->status);
  67         // FIXME for keepalives, respond immediately (asynchronously)
  68         // if not an RNDIS status, do like cdc_status(dev,urb) does
  69 }
  70 EXPORT_SYMBOL_GPL(rndis_status);
  71
  72 /*
  73  * RPC done RNDIS-style.  Caller guarantees:
  74  * - message is properly byteswapped
  75  * - there's no other request pending
  76  * - buf can hold up to 1KB response (required by RNDIS spec)
  77  * On return, the first few entries are already byteswapped.
  78  *
  79  * Call context is likely probe(), before interface name is known,
  80  * which is why we won't try to use it in the diagnostics.
  81  */
  82 int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf)
  83 {
  84         struct cdc_state        *info = (void *) &dev->data;
  85         int                     master_ifnum;
  86         int                     retval;
  87         unsigned                count;
  88         __le32                  rsp;
  89         u32                     xid = 0, msg_len, request_id;
  90
  91         /* REVISIT when this gets called from contexts other than probe() or
  92          * disconnect(): either serialize, or dispatch responses on xid
  93          */
  94
  95         /* Issue the request; xid is unique, don't bother byteswapping it */
  96         if (likely(buf->msg_type != RNDIS_MSG_HALT
  97                         && buf->msg_type != RNDIS_MSG_RESET)) {
  98                 xid = dev->xid++;
  99                 if (!xid)
 100                         xid = dev->xid++;
 101                 buf->request_id = (__force __le32) xid;
 102         }
 103         master_ifnum = info->control->cur_altsetting->desc.bInterfaceNumber;
 104         retval = usb_control_msg(dev->udev,
 105                 usb_sndctrlpipe(dev->udev, 0),
 106                 USB_CDC_SEND_ENCAPSULATED_COMMAND,
 107                 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 108                 0, master_ifnum,
 109                 buf, le32_to_cpu(buf->msg_len),
 110                 RNDIS_CONTROL_TIMEOUT_MS);
 111         if (unlikely(retval < 0 || xid == 0))
 112                 return retval;
 113
 114         // FIXME Seems like some devices discard responses when
 115         // we time out and cancel our "get response" requests...
 116         // so, this is fragile.  Probably need to poll for status.
 117
 118         /* ignore status endpoint, just poll the control channel;
 119          * the request probably completed immediately
 120          */
 121         rsp = buf->msg_type | RNDIS_MSG_COMPLETION;
 122         for (count = 0; count < 10; count++) {
 123                 memset(buf, 0, CONTROL_BUFFER_SIZE);
 124                 retval = usb_control_msg(dev->udev,
 125                         usb_rcvctrlpipe(dev->udev, 0),
 126                         USB_CDC_GET_ENCAPSULATED_RESPONSE,
 127                         USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 128                         0, master_ifnum,
 129                         buf, CONTROL_BUFFER_SIZE,
 130                         RNDIS_CONTROL_TIMEOUT_MS);
 131                 if (likely(retval >= 8)) {
 132                         msg_len = le32_to_cpu(buf->msg_len);
 133                         request_id = (__force u32) buf->request_id;
 134                         if (likely(buf->msg_type == rsp)) {
 135                                 if (likely(request_id == xid)) {
 136                                         if (unlikely(rsp == RNDIS_MSG_RESET_C))
 137                                                 return 0;
 138                                         if (likely(RNDIS_STATUS_SUCCESS
 139                                                         == buf->status))
 140                                                 return 0;
 141                                         dev_dbg(&info->control->dev,
 142                                                 "rndis reply status %08x\n",
 143                                                 le32_to_cpu(buf->status));
 144                                         return -EL3RST;
 145                                 }
 146                                 dev_dbg(&info->control->dev,
 147                                         "rndis reply id %d expected %d\n",
 148                                         request_id, xid);
 149                                 /* then likely retry */
 150                         } else switch (buf->msg_type) {
 151                         case RNDIS_MSG_INDICATE: {      /* fault/event */
 152                                 struct rndis_indicate *msg = (void *)buf;
 153                                 int state = 0;
 154
 155                                 switch (msg->status) {
 156                                 case RNDIS_STATUS_MEDIA_CONNECT:
 157                                         state = 1;
 158                                 case RNDIS_STATUS_MEDIA_DISCONNECT:
 159                                         dev_info(&info->control->dev,
 160                                                 "rndis media %sconnect\n",
 161                                                 !state?"dis":"");
 162                                         if (dev->driver_info->link_change)
 163                                                 dev->driver_info->link_change(
 164                                                         dev, state);
 165                                         break;
 166                                 default:
 167                                         dev_info(&info->control->dev,
 168                                                 "rndis indication: 0x%08x\n",
 169                                                 le32_to_cpu(msg->status));
 170                                 }
 171                                 }
 172                                 break;
 173                         case RNDIS_MSG_KEEPALIVE: {     /* ping */
 174                                 struct rndis_keepalive_c *msg = (void *)buf;
 175
 176                                 msg->msg_type = RNDIS_MSG_KEEPALIVE_C;
 177                                 msg->msg_len = ccpu2(sizeof *msg);
 178                                 msg->status = RNDIS_STATUS_SUCCESS;
 179                                 retval = usb_control_msg(dev->udev,
 180                                         usb_sndctrlpipe(dev->udev, 0),
 181                                         USB_CDC_SEND_ENCAPSULATED_COMMAND,
 182                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 183                                         0, master_ifnum,
 184                                         msg, sizeof *msg,
 185                                         RNDIS_CONTROL_TIMEOUT_MS);
 186                                 if (unlikely(retval < 0))
 187                                         dev_dbg(&info->control->dev,
 188                                                 "rndis keepalive err %d\n",
 189                                                 retval);
 190                                 }
 191                                 break;
 192                         default:
 193                                 dev_dbg(&info->control->dev,
 194                                         "unexpected rndis msg %08x len %d\n",
 195                                         le32_to_cpu(buf->msg_type), msg_len);
 196                         }
 197                 } else {
 198                         /* device probably issued a protocol stall; ignore */
 199                         dev_dbg(&info->control->dev,
 200                                 "rndis response error, code %d\n", retval);
 201                 }
 202                 msleep(2);
 203         }
 204         dev_dbg(&info->control->dev, "rndis response timeout\n");
 205         return -ETIMEDOUT;
 206 }
 207 EXPORT_SYMBOL_GPL(rndis_command);
 208
 209 /*
 210  * rndis_query:
 211  *
 212  * Performs a query for @oid along with 0 or more bytes of payload as
 213  * specified by @in_len. If @reply_len is not set to -1 then the reply
 214  * length is checked against this value, resulting in an error if it
 215  * doesn't match.
 216  *
 217  * NOTE: Adding a payload exactly or greater than the size of the expected
 218  * response payload is an evident requirement MSFT added for ActiveSync.
 219  *
 220  * The only exception is for OIDs that return a variably sized response,
 221  * in which case no payload should be added.  This undocumented (and
 222  * nonsensical!) issue was found by sniffing protocol requests from the
 223  * ActiveSync 4.1 Windows driver.
 224  */
 225 static int rndis_query(struct usbnet *dev, struct usb_interface *intf,
 226                 void *buf, u32 oid, u32 in_len,
 227                 void **reply, int *reply_len)
 228 {
 229         int retval;
 230         union {
 231                 void                    *buf;
 232                 struct rndis_msg_hdr    *header;
 233                 struct rndis_query      *get;
 234                 struct rndis_query_c    *get_c;
 235         } u;
 236         u32 off, len;
 237
 238         u.buf = buf;
 239
 240         memset(u.get, 0, sizeof *u.get + in_len);
 241         u.get->msg_type = RNDIS_MSG_QUERY;
 242         u.get->msg_len = cpu_to_le32(sizeof *u.get + in_len);
 243         u.get->oid = oid;
 244         u.get->len = cpu_to_le32(in_len);
 245         u.get->offset = ccpu2(20);
 246
 247         retval = rndis_command(dev, u.header);
 248         if (unlikely(retval < 0)) {
 249                 dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) failed, %d\n",
 250                                 oid, retval);
 251                 return retval;
 252         }
 253
 254         off = le32_to_cpu(u.get_c->offset);
 255         len = le32_to_cpu(u.get_c->len);
 256         if (unlikely((8 + off + len) > CONTROL_BUFFER_SIZE))
 257                 goto response_error;
 258
 259         if (*reply_len != -1 && len != *reply_len)
 260                 goto response_error;
 261
 262         *reply = (unsigned char *) &u.get_c->request_id + off;
 263         *reply_len = len;
 264
 265         return retval;
 266
 267 response_error:
 268         dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) "
 269                         "invalid response - off %d len %d\n",
 270                 oid, off, len);
 271         return -EDOM;
 272 }
 273
 274 int generic_rndis_bind(struct usbnet *dev, struct usb_interface *intf)
 275 {
 276         int                     retval;
 277         struct net_device       *net = dev->net;
 278         struct cdc_state        *info = (void *) &dev->data;
 279         union {
 280                 void                    *buf;
 281                 struct rndis_msg_hdr    *header;
 282                 struct rndis_init       *init;
 283                 struct rndis_init_c     *init_c;
 284                 struct rndis_query      *get;
 285                 struct rndis_query_c    *get_c;
 286                 struct rndis_set        *set;
 287                 struct rndis_set_c      *set_c;
 288                 struct rndis_halt       *halt;
 289         } u;
 290         u32                     tmp;
 291         int                     reply_len;
 292         unsigned char           *bp;
 293
 294         /* we can't rely on i/o from stack working, or stack allocation */
 295         u.buf = kmalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 296         if (!u.buf)
 297                 return -ENOMEM;
 298         retval = usbnet_generic_cdc_bind(dev, intf);
 299         if (retval < 0)
 300                 goto fail;
 301
 302         u.init->msg_type = RNDIS_MSG_INIT;
 303         u.init->msg_len = ccpu2(sizeof *u.init);
 304         u.init->major_version = ccpu2(1);
 305         u.init->minor_version = ccpu2(0);
 306
 307         /* max transfer (in spec) is 0x4000 at full speed, but for
 308          * TX we'll stick to one Ethernet packet plus RNDIS framing.
 309          * For RX we handle drivers that zero-pad to end-of-packet.
 310          * Don't let userspace change these settings.
 311          *
 312          * NOTE: there still seems to be wierdness here, as if we need
 313          * to do some more things to make sure WinCE targets accept this.
 314          * They default to jumbograms of 8KB or 16KB, which is absurd
 315          * for such low data rates and which is also more than Linux
 316          * can usually expect to allocate for SKB data...
 317          */
 318         net->hard_header_len += sizeof (struct rndis_data_hdr);
 319         dev->hard_mtu = net->mtu + net->hard_header_len;
 320
 321         dev->rx_urb_size = dev->hard_mtu + (dev->maxpacket + 1);
 322         dev->rx_urb_size &= ~(dev->maxpacket - 1);
 323         u.init->max_transfer_size = cpu_to_le32(dev->rx_urb_size);
 324
 325         net->change_mtu = NULL;
 326         retval = rndis_command(dev, u.header);
 327         if (unlikely(retval < 0)) {
 328                 /* it might not even be an RNDIS device!! */
 329                 dev_err(&intf->dev, "RNDIS init failed, %d\n", retval);
 330                 goto fail_and_release;
 331         }
 332         tmp = le32_to_cpu(u.init_c->max_transfer_size);
 333         if (tmp < dev->hard_mtu) {
 334                 if (tmp <= net->hard_header_len) {
 335                         dev_err(&intf->dev,
 336                                 "dev can't take %u byte packets (max %u)\n",
 337                                 dev->hard_mtu, tmp);
 338                         retval = -EINVAL;
 339                         goto halt_fail_and_release;
 340                 }
 341                 dev->hard_mtu = tmp;
 342                 net->mtu = dev->hard_mtu - net->hard_header_len;
 343                 dev_warn(&intf->dev,
 344                          "dev can't take %u byte packets (max %u), "
 345                          "adjusting MTU to %u\n",
 346                          dev->hard_mtu, tmp, net->mtu);
 347         }
 348
 349         /* REVISIT:  peripheral "alignment" request is ignored ... */
 350         dev_dbg(&intf->dev,
 351                 "hard mtu %u (%u from dev), rx buflen %Zu, align %d\n",
 352                 dev->hard_mtu, tmp, dev->rx_urb_size,
 353                 1 << le32_to_cpu(u.init_c->packet_alignment));
 354
 355         /* module has some device initialization code needs to be done right
 356          * after RNDIS_INIT */
 357         if (dev->driver_info->early_init &&
 358                         dev->driver_info->early_init(dev) != 0)
 359                 goto halt_fail_and_release;
 360
 361         /* Get designated host ethernet address */
 362         reply_len = ETH_ALEN;
 363         retval = rndis_query(dev, intf, u.buf, OID_802_3_PERMANENT_ADDRESS,
 364                         48, (void **) &bp, &reply_len);
 365         if (unlikely(retval< 0)) {
 366                 dev_err(&intf->dev, "rndis get ethaddr, %d\n", retval);
 367                 goto halt_fail_and_release;
 368         }
 369         memcpy(net->dev_addr, bp, ETH_ALEN);
 370
 371         /* set a nonzero filter to enable data transfers */
 372         memset(u.set, 0, sizeof *u.set);
 373         u.set->msg_type = RNDIS_MSG_SET;
 374         u.set->msg_len = ccpu2(4 + sizeof *u.set);
 375         u.set->oid = OID_GEN_CURRENT_PACKET_FILTER;
 376         u.set->len = ccpu2(4);
 377         u.set->offset = ccpu2((sizeof *u.set) - 8);
 378         *(__le32 *)(u.buf + sizeof *u.set) = RNDIS_DEFAULT_FILTER;
 379
 380         retval = rndis_command(dev, u.header);
 381         if (unlikely(retval < 0)) {
 382                 dev_err(&intf->dev, "rndis set packet filter, %d\n", retval);
 383                 goto halt_fail_and_release;
 384         }
 385
 386         retval = 0;
 387
 388         kfree(u.buf);
 389         return retval;
 390
 391 halt_fail_and_release:
 392         memset(u.halt, 0, sizeof *u.halt);
 393         u.halt->msg_type = RNDIS_MSG_HALT;
 394         u.halt->msg_len = ccpu2(sizeof *u.halt);
 395         (void) rndis_command(dev, (void *)u.halt);
 396 fail_and_release:
 397         usb_set_intfdata(info->data, NULL);
 398         usb_driver_release_interface(driver_of(intf), info->data);
 399         info->data = NULL;
 400 fail:
 401         kfree(u.buf);
 402         return retval;
 403 }
 404 EXPORT_SYMBOL_GPL(generic_rndis_bind);
 405
 406 void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
 407 {
 408         struct rndis_halt       *halt;
 409
 410         /* try to clear any rndis state/activity (no i/o from stack!) */
 411         halt = kzalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
 412         if (halt) {
 413                 halt->msg_type = RNDIS_MSG_HALT;
 414                 halt->msg_len = ccpu2(sizeof *halt);
 415                 (void) rndis_command(dev, (void *)halt);
 416                 kfree(halt);
 417         }
 418
 419         usbnet_cdc_unbind(dev, intf);
 420 }
 421 EXPORT_SYMBOL_GPL(rndis_unbind);
 422
 423 /*
 424  * DATA -- host must not write zlps
 425  */
 426 int rndis_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 427 {
 428         /* peripheral may have batched packets to us... */
 429         while (likely(skb->len)) {
 430                 struct rndis_data_hdr   *hdr = (void *)skb->data;
 431                 struct sk_buff          *skb2;
 432                 u32                     msg_len, data_offset, data_len;
 433
 434                 msg_len = le32_to_cpu(hdr->msg_len);
 435                 data_offset = le32_to_cpu(hdr->data_offset);
 436                 data_len = le32_to_cpu(hdr->data_len);
 437
 438                 /* don't choke if we see oob, per-packet data, etc */
 439                 if (unlikely(hdr->msg_type != RNDIS_MSG_PACKET
 440                                 || skb->len < msg_len
 441                                 || (data_offset + data_len + 8) > msg_len)) {
 442                         dev->stats.rx_frame_errors++;
 443                         devdbg(dev, "bad rndis message %d/%d/%d/%d, len %d",
 444                                 le32_to_cpu(hdr->msg_type),
 445                                 msg_len, data_offset, data_len, skb->len);
 446                         return 0;
 447                 }
 448                 skb_pull(skb, 8 + data_offset);
 449
 450                 /* at most one packet left? */
 451                 if (likely((data_len - skb->len) <= sizeof *hdr)) {
 452                         skb_trim(skb, data_len);
 453                         break;
 454                 }
 455
 456                 /* try to return all the packets in the batch */
 457                 skb2 = skb_clone(skb, GFP_ATOMIC);
 458                 if (unlikely(!skb2))
 459                         break;
 460                 skb_pull(skb, msg_len - sizeof *hdr);
 461                 skb_trim(skb2, data_len);
 462                 usbnet_skb_return(dev, skb2);
 463         }
 464
 465         /* caller will usbnet_skb_return the remaining packet */
 466         return 1;
 467 }
 468 EXPORT_SYMBOL_GPL(rndis_rx_fixup);
 469
 470 struct sk_buff *
 471 rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 472 {
 473         struct rndis_data_hdr   *hdr;
 474         struct sk_buff          *skb2;
 475         unsigned                len = skb->len;
 476
 477         if (likely(!skb_cloned(skb))) {
 478                 int     room = skb_headroom(skb);
 479
 480                 /* enough head room as-is? */
 481                 if (unlikely((sizeof *hdr) <= room))
 482                         goto fill;
 483
 484                 /* enough room, but needs to be readjusted? */
 485                 room += skb_tailroom(skb);
 486                 if (likely((sizeof *hdr) <= room)) {
 487                         skb->data = memmove(skb->head + sizeof *hdr,
 488                                             skb->data, len);
 489                         skb_set_tail_pointer(skb, len);
 490                         goto fill;
 491                 }
 492         }
 493
 494         /* create a new skb, with the correct size (and tailpad) */
 495         skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
 496         dev_kfree_skb_any(skb);
 497         if (unlikely(!skb2))
 498                 return skb2;
 499         skb = skb2;
 500
 501         /* fill out the RNDIS header.  we won't bother trying to batch
 502          * packets; Linux minimizes wasted bandwidth through tx queues.
 503          */
 504 fill:
 505         hdr = (void *) __skb_push(skb, sizeof *hdr);
 506         memset(hdr, 0, sizeof *hdr);
 507         hdr->msg_type = RNDIS_MSG_PACKET;
 508         hdr->msg_len = cpu_to_le32(skb->len);
 509         hdr->data_offset = ccpu2(sizeof(*hdr) - 8);
 510         hdr->data_len = cpu_to_le32(len);
 511
 512         /* FIXME make the last packet always be short ... */
 513         return skb;
 514 }
 515 EXPORT_SYMBOL_GPL(rndis_tx_fixup);
 516
 517
 518 static const struct driver_info rndis_info = {
 519         .description =  "RNDIS device",
 520         .flags =        FLAG_ETHER | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 521         .bind =         generic_rndis_bind,
 522         .unbind =       rndis_unbind,
 523         .status =       rndis_status,
 524         .rx_fixup =     rndis_rx_fixup,
 525         .tx_fixup =     rndis_tx_fixup,
 526 };
 527
 528 #undef ccpu2
 529
 530
 531 /*-------------------------------------------------------------------------*/
 532
 533 static const struct usb_device_id       products [] = {
 534 {
 535         /* RNDIS is MSFT's un-official variant of CDC ACM */
 536         USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
 537         .driver_info = (unsigned long) &rndis_info,
 538 }, {
 539         /* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
 540         USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
 541         .driver_info = (unsigned long) &rndis_info,
 542 },
 543         { },            // END
 544 };
 545 MODULE_DEVICE_TABLE(usb, products);
 546
 547 static struct usb_driver rndis_driver = {
 548         .name =         "rndis_host",
 549         .id_table =     products,
 550         .probe =        usbnet_probe,
 551         .disconnect =   usbnet_disconnect,
 552         .suspend =      usbnet_suspend,
 553         .resume =       usbnet_resume,
 554 };
 555
 556 static int __init rndis_init(void)
 557 {
 558         return usb_register(&rndis_driver);
 559 }
 560 module_init(rndis_init);
 561
 562 static void __exit rndis_exit(void)
 563 {
 564         usb_deregister(&rndis_driver);
 565 }
 566 module_exit(rndis_exit);
 567
 568 MODULE_AUTHOR("David Brownell");
 569 MODULE_DESCRIPTION("USB Host side RNDIS driver");
 570 MODULE_LICENSE("GPL");