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