drivers/usb/usbip/stub_dev.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2003-2008 Takahiro Hirofuchi
   4  */
   5
   6 #include <linux/device.h>
   7 #include <linux/file.h>
   8 #include <linux/kthread.h>
   9 #include <linux/module.h>
  10
  11 #include "usbip_common.h"
  12 #include "stub.h"
  13
  14 /*
  15  * usbip_status shows the status of usbip-host as long as this driver is bound
  16  * to the target device.
  17  */
  18 static ssize_t usbip_status_show(struct device *dev,
  19                                  struct device_attribute *attr, char *buf)
  20 {
  21         struct stub_device *sdev = dev_get_drvdata(dev);
  22         int status;
  23
  24         if (!sdev) {
  25                 dev_err(dev, "sdev is null\n");
  26                 return -ENODEV;
  27         }
  28
  29         spin_lock_irq(&sdev->ud.lock);
  30         status = sdev->ud.status;
  31         spin_unlock_irq(&sdev->ud.lock);
  32
  33         return snprintf(buf, PAGE_SIZE, "%d\n", status);
  34 }
  35 static DEVICE_ATTR_RO(usbip_status);
  36
  37 /*
  38  * usbip_sockfd gets a socket descriptor of an established TCP connection that
  39  * is used to transfer usbip requests by kernel threads. -1 is a magic number
  40  * by which usbip connection is finished.
  41  */
  42 static ssize_t store_sockfd(struct device *dev, struct device_attribute *attr,
  43                             const char *buf, size_t count)
  44 {
  45         struct stub_device *sdev = dev_get_drvdata(dev);
  46         int sockfd = 0;
  47         struct socket *socket;
  48         int rv;
  49
  50         if (!sdev) {
  51                 dev_err(dev, "sdev is null\n");
  52                 return -ENODEV;
  53         }
  54
  55         rv = sscanf(buf, "%d", &sockfd);
  56         if (rv != 1)
  57                 return -EINVAL;
  58
  59         if (sockfd != -1) {
  60                 int err;
  61
  62                 dev_info(dev, "stub up\n");
  63
  64                 spin_lock_irq(&sdev->ud.lock);
  65
  66                 if (sdev->ud.status != SDEV_ST_AVAILABLE) {
  67                         dev_err(dev, "not ready\n");
  68                         goto err;
  69                 }
  70
  71                 socket = sockfd_lookup(sockfd, &err);
  72                 if (!socket)
  73                         goto err;
  74
  75                 sdev->ud.tcp_socket = socket;
  76
  77                 spin_unlock_irq(&sdev->ud.lock);
  78
  79                 sdev->ud.tcp_rx = kthread_get_run(stub_rx_loop, &sdev->ud,
  80                                                   "stub_rx");
  81                 sdev->ud.tcp_tx = kthread_get_run(stub_tx_loop, &sdev->ud,
  82                                                   "stub_tx");
  83
  84                 spin_lock_irq(&sdev->ud.lock);
  85                 sdev->ud.status = SDEV_ST_USED;
  86                 spin_unlock_irq(&sdev->ud.lock);
  87
  88         } else {
  89                 dev_info(dev, "stub down\n");
  90
  91                 spin_lock_irq(&sdev->ud.lock);
  92                 if (sdev->ud.status != SDEV_ST_USED)
  93                         goto err;
  94
  95                 spin_unlock_irq(&sdev->ud.lock);
  96
  97                 usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN);
  98         }
  99
 100         return count;
 101
 102 err:
 103         spin_unlock_irq(&sdev->ud.lock);
 104         return -EINVAL;
 105 }
 106 static DEVICE_ATTR(usbip_sockfd, S_IWUSR, NULL, store_sockfd);
 107
 108 static int stub_add_files(struct device *dev)
 109 {
 110         int err = 0;
 111
 112         err = device_create_file(dev, &dev_attr_usbip_status);
 113         if (err)
 114                 goto err_status;
 115
 116         err = device_create_file(dev, &dev_attr_usbip_sockfd);
 117         if (err)
 118                 goto err_sockfd;
 119
 120         err = device_create_file(dev, &dev_attr_usbip_debug);
 121         if (err)
 122                 goto err_debug;
 123
 124         return 0;
 125
 126 err_debug:
 127         device_remove_file(dev, &dev_attr_usbip_sockfd);
 128 err_sockfd:
 129         device_remove_file(dev, &dev_attr_usbip_status);
 130 err_status:
 131         return err;
 132 }
 133
 134 static void stub_remove_files(struct device *dev)
 135 {
 136         device_remove_file(dev, &dev_attr_usbip_status);
 137         device_remove_file(dev, &dev_attr_usbip_sockfd);
 138         device_remove_file(dev, &dev_attr_usbip_debug);
 139 }
 140
 141 static void stub_shutdown_connection(struct usbip_device *ud)
 142 {
 143         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 144
 145         /*
 146          * When removing an exported device, kernel panic sometimes occurred
 147          * and then EIP was sk_wait_data of stub_rx thread. Is this because
 148          * sk_wait_data returned though stub_rx thread was already finished by
 149          * step 1?
 150          */
 151         if (ud->tcp_socket) {
 152                 dev_dbg(&sdev->udev->dev, "shutdown tcp_socket %p\n",
 153                         ud->tcp_socket);
 154                 kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
 155         }
 156
 157         /* 1. stop threads */
 158         if (ud->tcp_rx) {
 159                 kthread_stop_put(ud->tcp_rx);
 160                 ud->tcp_rx = NULL;
 161         }
 162         if (ud->tcp_tx) {
 163                 kthread_stop_put(ud->tcp_tx);
 164                 ud->tcp_tx = NULL;
 165         }
 166
 167         /*
 168          * 2. close the socket
 169          *
 170          * tcp_socket is freed after threads are killed so that usbip_xmit does
 171          * not touch NULL socket.
 172          */
 173         if (ud->tcp_socket) {
 174                 sockfd_put(ud->tcp_socket);
 175                 ud->tcp_socket = NULL;
 176         }
 177
 178         /* 3. free used data */
 179         stub_device_cleanup_urbs(sdev);
 180
 181         /* 4. free stub_unlink */
 182         {
 183                 unsigned long flags;
 184                 struct stub_unlink *unlink, *tmp;
 185
 186                 spin_lock_irqsave(&sdev->priv_lock, flags);
 187                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
 188                         list_del(&unlink->list);
 189                         kfree(unlink);
 190                 }
 191                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free,
 192                                          list) {
 193                         list_del(&unlink->list);
 194                         kfree(unlink);
 195                 }
 196                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 197         }
 198 }
 199
 200 static void stub_device_reset(struct usbip_device *ud)
 201 {
 202         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 203         struct usb_device *udev = sdev->udev;
 204         int ret;
 205
 206         dev_dbg(&udev->dev, "device reset");
 207
 208         ret = usb_lock_device_for_reset(udev, NULL);
 209         if (ret < 0) {
 210                 dev_err(&udev->dev, "lock for reset\n");
 211                 spin_lock_irq(&ud->lock);
 212                 ud->status = SDEV_ST_ERROR;
 213                 spin_unlock_irq(&ud->lock);
 214                 return;
 215         }
 216
 217         /* try to reset the device */
 218         ret = usb_reset_device(udev);
 219         usb_unlock_device(udev);
 220
 221         spin_lock_irq(&ud->lock);
 222         if (ret) {
 223                 dev_err(&udev->dev, "device reset\n");
 224                 ud->status = SDEV_ST_ERROR;
 225         } else {
 226                 dev_info(&udev->dev, "device reset\n");
 227                 ud->status = SDEV_ST_AVAILABLE;
 228         }
 229         spin_unlock_irq(&ud->lock);
 230 }
 231
 232 static void stub_device_unusable(struct usbip_device *ud)
 233 {
 234         spin_lock_irq(&ud->lock);
 235         ud->status = SDEV_ST_ERROR;
 236         spin_unlock_irq(&ud->lock);
 237 }
 238
 239 /**
 240  * stub_device_alloc - allocate a new stub_device struct
 241  * @udev: usb_device of a new device
 242  *
 243  * Allocates and initializes a new stub_device struct.
 244  */
 245 static struct stub_device *stub_device_alloc(struct usb_device *udev)
 246 {
 247         struct stub_device *sdev;
 248         int busnum = udev->bus->busnum;
 249         int devnum = udev->devnum;
 250
 251         dev_dbg(&udev->dev, "allocating stub device");
 252
 253         /* yes, it's a new device */
 254         sdev = kzalloc(sizeof(struct stub_device), GFP_KERNEL);
 255         if (!sdev)
 256                 return NULL;
 257
 258         sdev->udev = usb_get_dev(udev);
 259
 260         /*
 261          * devid is defined with devnum when this driver is first allocated.
 262          * devnum may change later if a device is reset. However, devid never
 263          * changes during a usbip connection.
 264          */
 265         sdev->devid             = (busnum << 16) | devnum;
 266         sdev->ud.side           = USBIP_STUB;
 267         sdev->ud.status         = SDEV_ST_AVAILABLE;
 268         spin_lock_init(&sdev->ud.lock);
 269         sdev->ud.tcp_socket     = NULL;
 270
 271         INIT_LIST_HEAD(&sdev->priv_init);
 272         INIT_LIST_HEAD(&sdev->priv_tx);
 273         INIT_LIST_HEAD(&sdev->priv_free);
 274         INIT_LIST_HEAD(&sdev->unlink_free);
 275         INIT_LIST_HEAD(&sdev->unlink_tx);
 276         spin_lock_init(&sdev->priv_lock);
 277
 278         init_waitqueue_head(&sdev->tx_waitq);
 279
 280         sdev->ud.eh_ops.shutdown = stub_shutdown_connection;
 281         sdev->ud.eh_ops.reset    = stub_device_reset;
 282         sdev->ud.eh_ops.unusable = stub_device_unusable;
 283
 284         usbip_start_eh(&sdev->ud);
 285
 286         dev_dbg(&udev->dev, "register new device\n");
 287
 288         return sdev;
 289 }
 290
 291 static void stub_device_free(struct stub_device *sdev)
 292 {
 293         kfree(sdev);
 294 }
 295
 296 static int stub_probe(struct usb_device *udev)
 297 {
 298         struct stub_device *sdev = NULL;
 299         const char *udev_busid = dev_name(&udev->dev);
 300         struct bus_id_priv *busid_priv;
 301         int rc;
 302
 303         dev_dbg(&udev->dev, "Enter\n");
 304
 305         /* check we should claim or not by busid_table */
 306         busid_priv = get_busid_priv(udev_busid);
 307         if (!busid_priv || (busid_priv->status == STUB_BUSID_REMOV) ||
 308             (busid_priv->status == STUB_BUSID_OTHER)) {
 309                 dev_info(&udev->dev,
 310                         "%s is not in match_busid table... skip!\n",
 311                         udev_busid);
 312
 313                 /*
 314                  * Return value should be ENODEV or ENOXIO to continue trying
 315                  * other matched drivers by the driver core.
 316                  * See driver_probe_device() in driver/base/dd.c
 317                  */
 318                 return -ENODEV;
 319         }
 320
 321         if (udev->descriptor.bDeviceClass == USB_CLASS_HUB) {
 322                 dev_dbg(&udev->dev, "%s is a usb hub device... skip!\n",
 323                          udev_busid);
 324                 return -ENODEV;
 325         }
 326
 327         if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
 328                 dev_dbg(&udev->dev,
 329                         "%s is attached on vhci_hcd... skip!\n",
 330                         udev_busid);
 331
 332                 return -ENODEV;
 333         }
 334
 335         /* ok, this is my device */
 336         sdev = stub_device_alloc(udev);
 337         if (!sdev)
 338                 return -ENOMEM;
 339
 340         dev_info(&udev->dev,
 341                 "usbip-host: register new device (bus %u dev %u)\n",
 342                 udev->bus->busnum, udev->devnum);
 343
 344         busid_priv->shutdown_busid = 0;
 345
 346         /* set private data to usb_device */
 347         dev_set_drvdata(&udev->dev, sdev);
 348         busid_priv->sdev = sdev;
 349         busid_priv->udev = udev;
 350
 351         /*
 352          * Claim this hub port.
 353          * It doesn't matter what value we pass as owner
 354          * (struct dev_state) as long as it is unique.
 355          */
 356         rc = usb_hub_claim_port(udev->parent, udev->portnum,
 357                         (struct usb_dev_state *) udev);
 358         if (rc) {
 359                 dev_dbg(&udev->dev, "unable to claim port\n");
 360                 goto err_port;
 361         }
 362
 363         rc = stub_add_files(&udev->dev);
 364         if (rc) {
 365                 dev_err(&udev->dev, "stub_add_files for %s\n", udev_busid);
 366                 goto err_files;
 367         }
 368         busid_priv->status = STUB_BUSID_ALLOC;
 369
 370         return 0;
 371 err_files:
 372         usb_hub_release_port(udev->parent, udev->portnum,
 373                              (struct usb_dev_state *) udev);
 374 err_port:
 375         dev_set_drvdata(&udev->dev, NULL);
 376         usb_put_dev(udev);
 377
 378         busid_priv->sdev = NULL;
 379         stub_device_free(sdev);
 380         return rc;
 381 }
 382
 383 static void shutdown_busid(struct bus_id_priv *busid_priv)
 384 {
 385         if (busid_priv->sdev && !busid_priv->shutdown_busid) {
 386                 busid_priv->shutdown_busid = 1;
 387                 usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);
 388
 389                 /* wait for the stop of the event handler */
 390                 usbip_stop_eh(&busid_priv->sdev->ud);
 391         }
 392 }
 393
 394 /*
 395  * called in usb_disconnect() or usb_deregister()
 396  * but only if actconfig(active configuration) exists
 397  */
 398 static void stub_disconnect(struct usb_device *udev)
 399 {
 400         struct stub_device *sdev;
 401         const char *udev_busid = dev_name(&udev->dev);
 402         struct bus_id_priv *busid_priv;
 403         int rc;
 404
 405         dev_dbg(&udev->dev, "Enter\n");
 406
 407         busid_priv = get_busid_priv(udev_busid);
 408         if (!busid_priv) {
 409                 BUG();
 410                 return;
 411         }
 412
 413         sdev = dev_get_drvdata(&udev->dev);
 414
 415         /* get stub_device */
 416         if (!sdev) {
 417                 dev_err(&udev->dev, "could not get device");
 418                 return;
 419         }
 420
 421         dev_set_drvdata(&udev->dev, NULL);
 422
 423         /*
 424          * NOTE: rx/tx threads are invoked for each usb_device.
 425          */
 426         stub_remove_files(&udev->dev);
 427
 428         /* release port */
 429         rc = usb_hub_release_port(udev->parent, udev->portnum,
 430                                   (struct usb_dev_state *) udev);
 431         if (rc) {
 432                 dev_dbg(&udev->dev, "unable to release port\n");
 433                 return;
 434         }
 435
 436         /* If usb reset is called from event handler */
 437         if (usbip_in_eh(current))
 438                 return;
 439
 440         /* shutdown the current connection */
 441         shutdown_busid(busid_priv);
 442
 443         usb_put_dev(sdev->udev);
 444
 445         /* free sdev */
 446         busid_priv->sdev = NULL;
 447         stub_device_free(sdev);
 448
 449         if (busid_priv->status == STUB_BUSID_ALLOC) {
 450                 busid_priv->status = STUB_BUSID_ADDED;
 451         } else {
 452                 busid_priv->status = STUB_BUSID_OTHER;
 453                 del_match_busid((char *)udev_busid);
 454         }
 455 }
 456
 457 #ifdef CONFIG_PM
 458
 459 /* These functions need usb_port_suspend and usb_port_resume,
 460  * which reside in drivers/usb/core/usb.h. Skip for now. */
 461
 462 static int stub_suspend(struct usb_device *udev, pm_message_t message)
 463 {
 464         dev_dbg(&udev->dev, "stub_suspend\n");
 465
 466         return 0;
 467 }
 468
 469 static int stub_resume(struct usb_device *udev, pm_message_t message)
 470 {
 471         dev_dbg(&udev->dev, "stub_resume\n");
 472
 473         return 0;
 474 }
 475
 476 #endif  /* CONFIG_PM */
 477
 478 struct usb_device_driver stub_driver = {
 479         .name           = "usbip-host",
 480         .probe          = stub_probe,
 481         .disconnect     = stub_disconnect,
 482 #ifdef CONFIG_PM
 483         .suspend        = stub_suspend,
 484         .resume         = stub_resume,
 485 #endif
 486         .supports_autosuspend   =       0,
 487 };