drivers/usb/usbip/stub_rx.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2003-2008 Takahiro Hirofuchi
   4  */
   5
   6 #include <asm/byteorder.h>
   7 #include <linux/kthread.h>
   8 #include <linux/usb.h>
   9 #include <linux/usb/hcd.h>
  10 #include <linux/scatterlist.h>
  11
  12 #include "usbip_common.h"
  13 #include "stub.h"
  14
  15 static int is_clear_halt_cmd(struct urb *urb)
  16 {
  17         struct usb_ctrlrequest *req;
  18
  19         req = (struct usb_ctrlrequest *) urb->setup_packet;
  20
  21         return (req->bRequest == USB_REQ_CLEAR_FEATURE) &&
  22                (req->bRequestType == USB_RECIP_ENDPOINT) &&
  23                (req->wValue == USB_ENDPOINT_HALT);
  24 }
  25
  26 static int is_set_interface_cmd(struct urb *urb)
  27 {
  28         struct usb_ctrlrequest *req;
  29
  30         req = (struct usb_ctrlrequest *) urb->setup_packet;
  31
  32         return (req->bRequest == USB_REQ_SET_INTERFACE) &&
  33                 (req->bRequestType == USB_RECIP_INTERFACE);
  34 }
  35
  36 static int is_set_configuration_cmd(struct urb *urb)
  37 {
  38         struct usb_ctrlrequest *req;
  39
  40         req = (struct usb_ctrlrequest *) urb->setup_packet;
  41
  42         return (req->bRequest == USB_REQ_SET_CONFIGURATION) &&
  43                 (req->bRequestType == USB_RECIP_DEVICE);
  44 }
  45
  46 static int is_reset_device_cmd(struct urb *urb)
  47 {
  48         struct usb_ctrlrequest *req;
  49         __u16 value;
  50         __u16 index;
  51
  52         req = (struct usb_ctrlrequest *) urb->setup_packet;
  53         value = le16_to_cpu(req->wValue);
  54         index = le16_to_cpu(req->wIndex);
  55
  56         if ((req->bRequest == USB_REQ_SET_FEATURE) &&
  57             (req->bRequestType == USB_RT_PORT) &&
  58             (value == USB_PORT_FEAT_RESET)) {
  59                 usbip_dbg_stub_rx("reset_device_cmd, port %u\n", index);
  60                 return 1;
  61         } else
  62                 return 0;
  63 }
  64
  65 static int tweak_clear_halt_cmd(struct urb *urb)
  66 {
  67         struct usb_ctrlrequest *req;
  68         int target_endp;
  69         int target_dir;
  70         int target_pipe;
  71         int ret;
  72
  73         req = (struct usb_ctrlrequest *) urb->setup_packet;
  74
  75         /*
  76          * The stalled endpoint is specified in the wIndex value. The endpoint
  77          * of the urb is the target of this clear_halt request (i.e., control
  78          * endpoint).
  79          */
  80         target_endp = le16_to_cpu(req->wIndex) & 0x000f;
  81
  82         /* the stalled endpoint direction is IN or OUT?. USB_DIR_IN is 0x80.  */
  83         target_dir = le16_to_cpu(req->wIndex) & 0x0080;
  84
  85         if (target_dir)
  86                 target_pipe = usb_rcvctrlpipe(urb->dev, target_endp);
  87         else
  88                 target_pipe = usb_sndctrlpipe(urb->dev, target_endp);
  89
  90         ret = usb_clear_halt(urb->dev, target_pipe);
  91         if (ret < 0)
  92                 dev_err(&urb->dev->dev,
  93                         "usb_clear_halt error: devnum %d endp %d ret %d\n",
  94                         urb->dev->devnum, target_endp, ret);
  95         else
  96                 dev_info(&urb->dev->dev,
  97                          "usb_clear_halt done: devnum %d endp %d\n",
  98                          urb->dev->devnum, target_endp);
  99
 100         return ret;
 101 }
 102
 103 static int tweak_set_interface_cmd(struct urb *urb)
 104 {
 105         struct usb_ctrlrequest *req;
 106         __u16 alternate;
 107         __u16 interface;
 108         int ret;
 109
 110         req = (struct usb_ctrlrequest *) urb->setup_packet;
 111         alternate = le16_to_cpu(req->wValue);
 112         interface = le16_to_cpu(req->wIndex);
 113
 114         usbip_dbg_stub_rx("set_interface: inf %u alt %u\n",
 115                           interface, alternate);
 116
 117         ret = usb_set_interface(urb->dev, interface, alternate);
 118         if (ret < 0)
 119                 dev_err(&urb->dev->dev,
 120                         "usb_set_interface error: inf %u alt %u ret %d\n",
 121                         interface, alternate, ret);
 122         else
 123                 dev_info(&urb->dev->dev,
 124                         "usb_set_interface done: inf %u alt %u\n",
 125                         interface, alternate);
 126
 127         return ret;
 128 }
 129
 130 static int tweak_set_configuration_cmd(struct urb *urb)
 131 {
 132         struct stub_priv *priv = (struct stub_priv *) urb->context;
 133         struct stub_device *sdev = priv->sdev;
 134         struct usb_ctrlrequest *req;
 135         __u16 config;
 136         int err;
 137
 138         req = (struct usb_ctrlrequest *) urb->setup_packet;
 139         config = le16_to_cpu(req->wValue);
 140
 141         usb_lock_device(sdev->udev);
 142         err = usb_set_configuration(sdev->udev, config);
 143         usb_unlock_device(sdev->udev);
 144         if (err && err != -ENODEV)
 145                 dev_err(&sdev->udev->dev, "can't set config #%d, error %d\n",
 146                         config, err);
 147         return err;
 148 }
 149
 150 static int tweak_reset_device_cmd(struct urb *urb)
 151 {
 152         struct stub_priv *priv = (struct stub_priv *) urb->context;
 153         struct stub_device *sdev = priv->sdev;
 154         int err;
 155
 156         dev_info(&urb->dev->dev, "usb_queue_reset_device\n");
 157
 158         err = usb_lock_device_for_reset(sdev->udev, NULL);
 159         if (err < 0) {
 160                 dev_err(&urb->dev->dev, "could not obtain lock to reset device\n");
 161                 return err;
 162         }
 163         err = usb_reset_device(sdev->udev);
 164         usb_unlock_device(sdev->udev);
 165
 166         return err;
 167 }
 168
 169 /*
 170  * clear_halt, set_interface, and set_configuration require special tricks.
 171  * Returns 1 if request was tweaked, 0 otherwise.
 172  */
 173 static int tweak_special_requests(struct urb *urb)
 174 {
 175         int err;
 176
 177         if (!urb || !urb->setup_packet)
 178                 return 0;
 179
 180         if (usb_pipetype(urb->pipe) != PIPE_CONTROL)
 181                 return 0;
 182
 183         if (is_clear_halt_cmd(urb))
 184                 /* tweak clear_halt */
 185                 err = tweak_clear_halt_cmd(urb);
 186
 187         else if (is_set_interface_cmd(urb))
 188                 /* tweak set_interface */
 189                 err = tweak_set_interface_cmd(urb);
 190
 191         else if (is_set_configuration_cmd(urb))
 192                 /* tweak set_configuration */
 193                 err = tweak_set_configuration_cmd(urb);
 194
 195         else if (is_reset_device_cmd(urb))
 196                 err = tweak_reset_device_cmd(urb);
 197         else {
 198                 usbip_dbg_stub_rx("no need to tweak\n");
 199                 return 0;
 200         }
 201
 202         return !err;
 203 }
 204
 205 /*
 206  * stub_recv_unlink() unlinks the URB by a call to usb_unlink_urb().
 207  * By unlinking the urb asynchronously, stub_rx can continuously
 208  * process coming urbs.  Even if the urb is unlinked, its completion
 209  * handler will be called and stub_tx will send a return pdu.
 210  *
 211  * See also comments about unlinking strategy in vhci_hcd.c.
 212  */
 213 static int stub_recv_cmd_unlink(struct stub_device *sdev,
 214                                 struct usbip_header *pdu)
 215 {
 216         int ret, i;
 217         unsigned long flags;
 218         struct stub_priv *priv;
 219
 220         spin_lock_irqsave(&sdev->priv_lock, flags);
 221
 222         list_for_each_entry(priv, &sdev->priv_init, list) {
 223                 if (priv->seqnum != pdu->u.cmd_unlink.seqnum)
 224                         continue;
 225
 226                 /*
 227                  * This matched urb is not completed yet (i.e., be in
 228                  * flight in usb hcd hardware/driver). Now we are
 229                  * cancelling it. The unlinking flag means that we are
 230                  * now not going to return the normal result pdu of a
 231                  * submission request, but going to return a result pdu
 232                  * of the unlink request.
 233                  */
 234                 priv->unlinking = 1;
 235
 236                 /*
 237                  * In the case that unlinking flag is on, prev->seqnum
 238                  * is changed from the seqnum of the cancelling urb to
 239                  * the seqnum of the unlink request. This will be used
 240                  * to make the result pdu of the unlink request.
 241                  */
 242                 priv->seqnum = pdu->base.seqnum;
 243
 244                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 245
 246                 /*
 247                  * usb_unlink_urb() is now out of spinlocking to avoid
 248                  * spinlock recursion since stub_complete() is
 249                  * sometimes called in this context but not in the
 250                  * interrupt context.  If stub_complete() is executed
 251                  * before we call usb_unlink_urb(), usb_unlink_urb()
 252                  * will return an error value. In this case, stub_tx
 253                  * will return the result pdu of this unlink request
 254                  * though submission is completed and actual unlinking
 255                  * is not executed. OK?
 256                  */
 257                 /* In the above case, urb->status is not -ECONNRESET,
 258                  * so a driver in a client host will know the failure
 259                  * of the unlink request ?
 260                  */
 261                 for (i = priv->completed_urbs; i < priv->num_urbs; i++) {
 262                         ret = usb_unlink_urb(priv->urbs[i]);
 263                         if (ret != -EINPROGRESS)
 264                                 dev_err(&priv->urbs[i]->dev->dev,
 265                                         "failed to unlink %d/%d urb of seqnum %lu, ret %d\n",
 266                                         i + 1, priv->num_urbs,
 267                                         priv->seqnum, ret);
 268                 }
 269                 return 0;
 270         }
 271
 272         usbip_dbg_stub_rx("seqnum %d is not pending\n",
 273                           pdu->u.cmd_unlink.seqnum);
 274
 275         /*
 276          * The urb of the unlink target is not found in priv_init queue. It was
 277          * already completed and its results is/was going to be sent by a
 278          * CMD_RET pdu. In this case, usb_unlink_urb() is not needed. We only
 279          * return the completeness of this unlink request to vhci_hcd.
 280          */
 281         stub_enqueue_ret_unlink(sdev, pdu->base.seqnum, 0);
 282
 283         spin_unlock_irqrestore(&sdev->priv_lock, flags);
 284
 285         return 0;
 286 }
 287
 288 static int valid_request(struct stub_device *sdev, struct usbip_header *pdu)
 289 {
 290         struct usbip_device *ud = &sdev->ud;
 291         int valid = 0;
 292
 293         if (pdu->base.devid == sdev->devid) {
 294                 spin_lock_irq(&ud->lock);
 295                 if (ud->status == SDEV_ST_USED) {
 296                         /* A request is valid. */
 297                         valid = 1;
 298                 }
 299                 spin_unlock_irq(&ud->lock);
 300         }
 301
 302         return valid;
 303 }
 304
 305 static struct stub_priv *stub_priv_alloc(struct stub_device *sdev,
 306                                          struct usbip_header *pdu)
 307 {
 308         struct stub_priv *priv;
 309         struct usbip_device *ud = &sdev->ud;
 310         unsigned long flags;
 311
 312         spin_lock_irqsave(&sdev->priv_lock, flags);
 313
 314         priv = kmem_cache_zalloc(stub_priv_cache, GFP_ATOMIC);
 315         if (!priv) {
 316                 dev_err(&sdev->udev->dev, "alloc stub_priv\n");
 317                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 318                 usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
 319                 return NULL;
 320         }
 321
 322         priv->seqnum = pdu->base.seqnum;
 323         priv->sdev = sdev;
 324
 325         /*
 326          * After a stub_priv is linked to a list_head,
 327          * our error handler can free allocated data.
 328          */
 329         list_add_tail(&priv->list, &sdev->priv_init);
 330
 331         spin_unlock_irqrestore(&sdev->priv_lock, flags);
 332
 333         return priv;
 334 }
 335
 336 static int get_pipe(struct stub_device *sdev, struct usbip_header *pdu)
 337 {
 338         struct usb_device *udev = sdev->udev;
 339         struct usb_host_endpoint *ep;
 340         struct usb_endpoint_descriptor *epd = NULL;
 341         int epnum = pdu->base.ep;
 342         int dir = pdu->base.direction;
 343
 344         if (epnum < 0 || epnum > 15)
 345                 goto err_ret;
 346
 347         if (dir == USBIP_DIR_IN)
 348                 ep = udev->ep_in[epnum & 0x7f];
 349         else
 350                 ep = udev->ep_out[epnum & 0x7f];
 351         if (!ep)
 352                 goto err_ret;
 353
 354         epd = &ep->desc;
 355
 356         if (usb_endpoint_xfer_control(epd)) {
 357                 if (dir == USBIP_DIR_OUT)
 358                         return usb_sndctrlpipe(udev, epnum);
 359                 else
 360                         return usb_rcvctrlpipe(udev, epnum);
 361         }
 362
 363         if (usb_endpoint_xfer_bulk(epd)) {
 364                 if (dir == USBIP_DIR_OUT)
 365                         return usb_sndbulkpipe(udev, epnum);
 366                 else
 367                         return usb_rcvbulkpipe(udev, epnum);
 368         }
 369
 370         if (usb_endpoint_xfer_int(epd)) {
 371                 if (dir == USBIP_DIR_OUT)
 372                         return usb_sndintpipe(udev, epnum);
 373                 else
 374                         return usb_rcvintpipe(udev, epnum);
 375         }
 376
 377         if (usb_endpoint_xfer_isoc(epd)) {
 378                 /* validate number of packets */
 379                 if (pdu->u.cmd_submit.number_of_packets < 0 ||
 380                     pdu->u.cmd_submit.number_of_packets >
 381                     USBIP_MAX_ISO_PACKETS) {
 382                         dev_err(&sdev->udev->dev,
 383                                 "CMD_SUBMIT: isoc invalid num packets %d\n",
 384                                 pdu->u.cmd_submit.number_of_packets);
 385                         return -1;
 386                 }
 387                 if (dir == USBIP_DIR_OUT)
 388                         return usb_sndisocpipe(udev, epnum);
 389                 else
 390                         return usb_rcvisocpipe(udev, epnum);
 391         }
 392
 393 err_ret:
 394         /* NOT REACHED */
 395         dev_err(&sdev->udev->dev, "CMD_SUBMIT: invalid epnum %d\n", epnum);
 396         return -1;
 397 }
 398
 399 static void masking_bogus_flags(struct urb *urb)
 400 {
 401         int                             xfertype;
 402         struct usb_device               *dev;
 403         struct usb_host_endpoint        *ep;
 404         int                             is_out;
 405         unsigned int    allowed;
 406
 407         if (!urb || urb->hcpriv || !urb->complete)
 408                 return;
 409         dev = urb->dev;
 410         if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED))
 411                 return;
 412
 413         ep = (usb_pipein(urb->pipe) ? dev->ep_in : dev->ep_out)
 414                 [usb_pipeendpoint(urb->pipe)];
 415         if (!ep)
 416                 return;
 417
 418         xfertype = usb_endpoint_type(&ep->desc);
 419         if (xfertype == USB_ENDPOINT_XFER_CONTROL) {
 420                 struct usb_ctrlrequest *setup =
 421                         (struct usb_ctrlrequest *) urb->setup_packet;
 422
 423                 if (!setup)
 424                         return;
 425                 is_out = !(setup->bRequestType & USB_DIR_IN) ||
 426                         !setup->wLength;
 427         } else {
 428                 is_out = usb_endpoint_dir_out(&ep->desc);
 429         }
 430
 431         /* enforce simple/standard policy */
 432         allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT |
 433                    URB_DIR_MASK | URB_FREE_BUFFER);
 434         switch (xfertype) {
 435         case USB_ENDPOINT_XFER_BULK:
 436                 if (is_out)
 437                         allowed |= URB_ZERO_PACKET;
 438                 fallthrough;
 439         default:                        /* all non-iso endpoints */
 440                 if (!is_out)
 441                         allowed |= URB_SHORT_NOT_OK;
 442                 break;
 443         case USB_ENDPOINT_XFER_ISOC:
 444                 allowed |= URB_ISO_ASAP;
 445                 break;
 446         }
 447         urb->transfer_flags &= allowed;
 448 }
 449
 450 static int stub_recv_xbuff(struct usbip_device *ud, struct stub_priv *priv)
 451 {
 452         int ret;
 453         int i;
 454
 455         for (i = 0; i < priv->num_urbs; i++) {
 456                 ret = usbip_recv_xbuff(ud, priv->urbs[i]);
 457                 if (ret < 0)
 458                         break;
 459         }
 460
 461         return ret;
 462 }
 463
 464 static void stub_recv_cmd_submit(struct stub_device *sdev,
 465                                  struct usbip_header *pdu)
 466 {
 467         struct stub_priv *priv;
 468         struct usbip_device *ud = &sdev->ud;
 469         struct usb_device *udev = sdev->udev;
 470         struct scatterlist *sgl = NULL, *sg;
 471         void *buffer = NULL;
 472         unsigned long long buf_len;
 473         int nents;
 474         int num_urbs = 1;
 475         int pipe = get_pipe(sdev, pdu);
 476         int use_sg = pdu->u.cmd_submit.transfer_flags & USBIP_URB_DMA_MAP_SG;
 477         int support_sg = 1;
 478         int np = 0;
 479         int ret, i;
 480         int is_tweaked;
 481
 482         if (pipe == -1)
 483                 return;
 484
 485         /*
 486          * Smatch reported the error case where use_sg is true and buf_len is 0.
 487          * In this case, It adds SDEV_EVENT_ERROR_MALLOC and stub_priv will be
 488          * released by stub event handler and connection will be shut down.
 489          */
 490         priv = stub_priv_alloc(sdev, pdu);
 491         if (!priv)
 492                 return;
 493
 494         buf_len = (unsigned long long)pdu->u.cmd_submit.transfer_buffer_length;
 495
 496         if (use_sg && !buf_len) {
 497                 dev_err(&udev->dev, "sg buffer with zero length\n");
 498                 goto err_malloc;
 499         }
 500
 501         /* allocate urb transfer buffer, if needed */
 502         if (buf_len) {
 503                 if (use_sg) {
 504                         sgl = sgl_alloc(buf_len, GFP_KERNEL, &nents);
 505                         if (!sgl)
 506                                 goto err_malloc;
 507
 508                         /* Check if the server's HCD supports SG */
 509                         if (!udev->bus->sg_tablesize) {
 510                                 /*
 511                                  * If the server's HCD doesn't support SG, break
 512                                  * a single SG request into several URBs and map
 513                                  * each SG list entry to corresponding URB
 514                                  * buffer. The previously allocated SG list is
 515                                  * stored in priv->sgl (If the server's HCD
 516                                  * support SG, SG list is stored only in
 517                                  * urb->sg) and it is used as an indicator that
 518                                  * the server split single SG request into
 519                                  * several URBs. Later, priv->sgl is used by
 520                                  * stub_complete() and stub_send_ret_submit() to
 521                                  * reassemble the divied URBs.
 522                                  */
 523                                 support_sg = 0;
 524                                 num_urbs = nents;
 525                                 priv->completed_urbs = 0;
 526                                 pdu->u.cmd_submit.transfer_flags &=
 527                                                                 ~USBIP_URB_DMA_MAP_SG;
 528                         }
 529                 } else {
 530                         buffer = kzalloc(buf_len, GFP_KERNEL);
 531                         if (!buffer)
 532                                 goto err_malloc;
 533                 }
 534         }
 535
 536         /* allocate urb array */
 537         priv->num_urbs = num_urbs;
 538         priv->urbs = kmalloc_array(num_urbs, sizeof(*priv->urbs), GFP_KERNEL);
 539         if (!priv->urbs)
 540                 goto err_urbs;
 541
 542         /* setup a urb */
 543         if (support_sg) {
 544                 if (usb_pipeisoc(pipe))
 545                         np = pdu->u.cmd_submit.number_of_packets;
 546
 547                 priv->urbs[0] = usb_alloc_urb(np, GFP_KERNEL);
 548                 if (!priv->urbs[0])
 549                         goto err_urb;
 550
 551                 if (buf_len) {
 552                         if (use_sg) {
 553                                 priv->urbs[0]->sg = sgl;
 554                                 priv->urbs[0]->num_sgs = nents;
 555                                 priv->urbs[0]->transfer_buffer = NULL;
 556                         } else {
 557                                 priv->urbs[0]->transfer_buffer = buffer;
 558                         }
 559                 }
 560
 561                 /* copy urb setup packet */
 562                 priv->urbs[0]->setup_packet = kmemdup(&pdu->u.cmd_submit.setup,
 563                                         8, GFP_KERNEL);
 564                 if (!priv->urbs[0]->setup_packet) {
 565                         usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
 566                         return;
 567                 }
 568
 569                 usbip_pack_pdu(pdu, priv->urbs[0], USBIP_CMD_SUBMIT, 0);
 570         } else {
 571                 for_each_sg(sgl, sg, nents, i) {
 572                         priv->urbs[i] = usb_alloc_urb(0, GFP_KERNEL);
 573                         /* The URBs which is previously allocated will be freed
 574                          * in stub_device_cleanup_urbs() if error occurs.
 575                          */
 576                         if (!priv->urbs[i])
 577                                 goto err_urb;
 578
 579                         usbip_pack_pdu(pdu, priv->urbs[i], USBIP_CMD_SUBMIT, 0);
 580                         priv->urbs[i]->transfer_buffer = sg_virt(sg);
 581                         priv->urbs[i]->transfer_buffer_length = sg->length;
 582                 }
 583                 priv->sgl = sgl;
 584         }
 585
 586         for (i = 0; i < num_urbs; i++) {
 587                 /* set other members from the base header of pdu */
 588                 priv->urbs[i]->context = (void *) priv;
 589                 priv->urbs[i]->dev = udev;
 590                 priv->urbs[i]->pipe = pipe;
 591                 priv->urbs[i]->complete = stub_complete;
 592
 593                 /*
 594                  * all URBs belong to a single PDU, so a global is_tweaked flag is
 595                  * enough
 596                  */
 597                 is_tweaked = tweak_special_requests(priv->urbs[i]);
 598
 599                 masking_bogus_flags(priv->urbs[i]);
 600         }
 601
 602         if (stub_recv_xbuff(ud, priv) < 0)
 603                 return;
 604
 605         if (usbip_recv_iso(ud, priv->urbs[0]) < 0)
 606                 return;
 607
 608         /* urb is now ready to submit */
 609         for (i = 0; i < priv->num_urbs; i++) {
 610                 if (!is_tweaked) {
 611                         ret = usb_submit_urb(priv->urbs[i], GFP_KERNEL);
 612
 613                         if (ret == 0)
 614                                 usbip_dbg_stub_rx("submit urb ok, seqnum %u\n",
 615                                                 pdu->base.seqnum);
 616                         else {
 617                                 dev_err(&udev->dev, "submit_urb error, %d\n", ret);
 618                                 usbip_dump_header(pdu);
 619                                 usbip_dump_urb(priv->urbs[i]);
 620
 621                                 /*
 622                                  * Pessimistic.
 623                                  * This connection will be discarded.
 624                                  */
 625                                 usbip_event_add(ud, SDEV_EVENT_ERROR_SUBMIT);
 626                                 break;
 627                         }
 628                 } else {
 629                         /*
 630                          * An identical URB was already submitted in
 631                          * tweak_special_requests(). Skip submitting this URB to not
 632                          * duplicate the request.
 633                          */
 634                         priv->urbs[i]->status = 0;
 635                         stub_complete(priv->urbs[i]);
 636                 }
 637         }
 638
 639         usbip_dbg_stub_rx("Leave\n");
 640         return;
 641
 642 err_urb:
 643         kfree(priv->urbs);
 644 err_urbs:
 645         kfree(buffer);
 646         sgl_free(sgl);
 647 err_malloc:
 648         usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
 649 }
 650
 651 /* recv a pdu */
 652 static void stub_rx_pdu(struct usbip_device *ud)
 653 {
 654         int ret;
 655         struct usbip_header pdu;
 656         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 657         struct device *dev = &sdev->udev->dev;
 658
 659         usbip_dbg_stub_rx("Enter\n");
 660
 661         memset(&pdu, 0, sizeof(pdu));
 662
 663         /* receive a pdu header */
 664         ret = usbip_recv(ud->tcp_socket, &pdu, sizeof(pdu));
 665         if (ret != sizeof(pdu)) {
 666                 dev_err(dev, "recv a header, %d\n", ret);
 667                 usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
 668                 return;
 669         }
 670
 671         usbip_header_correct_endian(&pdu, 0);
 672
 673         if (usbip_dbg_flag_stub_rx)
 674                 usbip_dump_header(&pdu);
 675
 676         if (!valid_request(sdev, &pdu)) {
 677                 dev_err(dev, "recv invalid request\n");
 678                 usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
 679                 return;
 680         }
 681
 682         switch (pdu.base.command) {
 683         case USBIP_CMD_UNLINK:
 684                 stub_recv_cmd_unlink(sdev, &pdu);
 685                 break;
 686
 687         case USBIP_CMD_SUBMIT:
 688                 stub_recv_cmd_submit(sdev, &pdu);
 689                 break;
 690
 691         default:
 692                 /* NOTREACHED */
 693                 dev_err(dev, "unknown pdu\n");
 694                 usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
 695                 break;
 696         }
 697 }
 698
 699 int stub_rx_loop(void *data)
 700 {
 701         struct usbip_device *ud = data;
 702
 703         while (!kthread_should_stop()) {
 704                 if (usbip_event_happened(ud))
 705                         break;
 706
 707                 stub_rx_pdu(ud);
 708         }
 709
 710         return 0;
 711 }