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 sockfd %d\n", ud->sockfd);
 153                 kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
 154         }
 155
 156         /* 1. stop threads */
 157         if (ud->tcp_rx) {
 158                 kthread_stop_put(ud->tcp_rx);
 159                 ud->tcp_rx = NULL;
 160         }
 161         if (ud->tcp_tx) {
 162                 kthread_stop_put(ud->tcp_tx);
 163                 ud->tcp_tx = NULL;
 164         }
 165
 166         /*
 167          * 2. close the socket
 168          *
 169          * tcp_socket is freed after threads are killed so that usbip_xmit does
 170          * not touch NULL socket.
 171          */
 172         if (ud->tcp_socket) {
 173                 sockfd_put(ud->tcp_socket);
 174                 ud->tcp_socket = NULL;
 175         }
 176
 177         /* 3. free used data */
 178         stub_device_cleanup_urbs(sdev);
 179
 180         /* 4. free stub_unlink */
 181         {
 182                 unsigned long flags;
 183                 struct stub_unlink *unlink, *tmp;
 184
 185                 spin_lock_irqsave(&sdev->priv_lock, flags);
 186                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
 187                         list_del(&unlink->list);
 188                         kfree(unlink);
 189                 }
 190                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free,
 191                                          list) {
 192                         list_del(&unlink->list);
 193                         kfree(unlink);
 194                 }
 195                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 196         }
 197 }
 198
 199 static void stub_device_reset(struct usbip_device *ud)
 200 {
 201         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 202         struct usb_device *udev = sdev->udev;
 203         int ret;
 204
 205         dev_dbg(&udev->dev, "device reset");
 206
 207         ret = usb_lock_device_for_reset(udev, NULL);
 208         if (ret < 0) {
 209                 dev_err(&udev->dev, "lock for reset\n");
 210                 spin_lock_irq(&ud->lock);
 211                 ud->status = SDEV_ST_ERROR;
 212                 spin_unlock_irq(&ud->lock);
 213                 return;
 214         }
 215
 216         /* try to reset the device */
 217         ret = usb_reset_device(udev);
 218         usb_unlock_device(udev);
 219
 220         spin_lock_irq(&ud->lock);
 221         if (ret) {
 222                 dev_err(&udev->dev, "device reset\n");
 223                 ud->status = SDEV_ST_ERROR;
 224         } else {
 225                 dev_info(&udev->dev, "device reset\n");
 226                 ud->status = SDEV_ST_AVAILABLE;
 227         }
 228         spin_unlock_irq(&ud->lock);
 229 }
 230
 231 static void stub_device_unusable(struct usbip_device *ud)
 232 {
 233         spin_lock_irq(&ud->lock);
 234         ud->status = SDEV_ST_ERROR;
 235         spin_unlock_irq(&ud->lock);
 236 }
 237
 238 /**
 239  * stub_device_alloc - allocate a new stub_device struct
 240  * @udev: usb_device of a new device
 241  *
 242  * Allocates and initializes a new stub_device struct.
 243  */
 244 static struct stub_device *stub_device_alloc(struct usb_device *udev)
 245 {
 246         struct stub_device *sdev;
 247         int busnum = udev->bus->busnum;
 248         int devnum = udev->devnum;
 249
 250         dev_dbg(&udev->dev, "allocating stub device");
 251
 252         /* yes, it's a new device */
 253         sdev = kzalloc(sizeof(struct stub_device), GFP_KERNEL);
 254         if (!sdev)
 255                 return NULL;
 256
 257         sdev->udev = usb_get_dev(udev);
 258
 259         /*
 260          * devid is defined with devnum when this driver is first allocated.
 261          * devnum may change later if a device is reset. However, devid never
 262          * changes during a usbip connection.
 263          */
 264         sdev->devid             = (busnum << 16) | devnum;
 265         sdev->ud.side           = USBIP_STUB;
 266         sdev->ud.status         = SDEV_ST_AVAILABLE;
 267         spin_lock_init(&sdev->ud.lock);
 268         sdev->ud.tcp_socket     = NULL;
 269
 270         INIT_LIST_HEAD(&sdev->priv_init);
 271         INIT_LIST_HEAD(&sdev->priv_tx);
 272         INIT_LIST_HEAD(&sdev->priv_free);
 273         INIT_LIST_HEAD(&sdev->unlink_free);
 274         INIT_LIST_HEAD(&sdev->unlink_tx);
 275         spin_lock_init(&sdev->priv_lock);
 276
 277         init_waitqueue_head(&sdev->tx_waitq);
 278
 279         sdev->ud.eh_ops.shutdown = stub_shutdown_connection;
 280         sdev->ud.eh_ops.reset    = stub_device_reset;
 281         sdev->ud.eh_ops.unusable = stub_device_unusable;
 282
 283         usbip_start_eh(&sdev->ud);
 284
 285         dev_dbg(&udev->dev, "register new device\n");
 286
 287         return sdev;
 288 }
 289
 290 static void stub_device_free(struct stub_device *sdev)
 291 {
 292         kfree(sdev);
 293 }
 294
 295 static int stub_probe(struct usb_device *udev)
 296 {
 297         struct stub_device *sdev = NULL;
 298         const char *udev_busid = dev_name(&udev->dev);
 299         struct bus_id_priv *busid_priv;
 300         int rc;
 301
 302         dev_dbg(&udev->dev, "Enter\n");
 303
 304         /* check we should claim or not by busid_table */
 305         busid_priv = get_busid_priv(udev_busid);
 306         if (!busid_priv || (busid_priv->status == STUB_BUSID_REMOV) ||
 307             (busid_priv->status == STUB_BUSID_OTHER)) {
 308                 dev_info(&udev->dev,
 309                         "%s is not in match_busid table... skip!\n",
 310                         udev_busid);
 311
 312                 /*
 313                  * Return value should be ENODEV or ENOXIO to continue trying
 314                  * other matched drivers by the driver core.
 315                  * See driver_probe_device() in driver/base/dd.c
 316                  */
 317                 return -ENODEV;
 318         }
 319
 320         if (udev->descriptor.bDeviceClass == USB_CLASS_HUB) {
 321                 dev_dbg(&udev->dev, "%s is a usb hub device... skip!\n",
 322                          udev_busid);
 323                 return -ENODEV;
 324         }
 325
 326         if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
 327                 dev_dbg(&udev->dev,
 328                         "%s is attached on vhci_hcd... skip!\n",
 329                         udev_busid);
 330
 331                 return -ENODEV;
 332         }
 333
 334         /* ok, this is my device */
 335         sdev = stub_device_alloc(udev);
 336         if (!sdev)
 337                 return -ENOMEM;
 338
 339         dev_info(&udev->dev,
 340                 "usbip-host: register new device (bus %u dev %u)\n",
 341                 udev->bus->busnum, udev->devnum);
 342
 343         busid_priv->shutdown_busid = 0;
 344
 345         /* set private data to usb_device */
 346         dev_set_drvdata(&udev->dev, sdev);
 347         busid_priv->sdev = sdev;
 348         busid_priv->udev = udev;
 349
 350         /*
 351          * Claim this hub port.
 352          * It doesn't matter what value we pass as owner
 353          * (struct dev_state) as long as it is unique.
 354          */
 355         rc = usb_hub_claim_port(udev->parent, udev->portnum,
 356                         (struct usb_dev_state *) udev);
 357         if (rc) {
 358                 dev_dbg(&udev->dev, "unable to claim port\n");
 359                 goto err_port;
 360         }
 361
 362         rc = stub_add_files(&udev->dev);
 363         if (rc) {
 364                 dev_err(&udev->dev, "stub_add_files for %s\n", udev_busid);
 365                 goto err_files;
 366         }
 367         busid_priv->status = STUB_BUSID_ALLOC;
 368
 369         return 0;
 370 err_files:
 371         usb_hub_release_port(udev->parent, udev->portnum,
 372                              (struct usb_dev_state *) udev);
 373 err_port:
 374         dev_set_drvdata(&udev->dev, NULL);
 375         usb_put_dev(udev);
 376
 377         busid_priv->sdev = NULL;
 378         stub_device_free(sdev);
 379         return rc;
 380 }
 381
 382 static void shutdown_busid(struct bus_id_priv *busid_priv)
 383 {
 384         if (busid_priv->sdev && !busid_priv->shutdown_busid) {
 385                 busid_priv->shutdown_busid = 1;
 386                 usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);
 387
 388                 /* wait for the stop of the event handler */
 389                 usbip_stop_eh(&busid_priv->sdev->ud);
 390         }
 391 }
 392
 393 /*
 394  * called in usb_disconnect() or usb_deregister()
 395  * but only if actconfig(active configuration) exists
 396  */
 397 static void stub_disconnect(struct usb_device *udev)
 398 {
 399         struct stub_device *sdev;
 400         const char *udev_busid = dev_name(&udev->dev);
 401         struct bus_id_priv *busid_priv;
 402         int rc;
 403
 404         dev_dbg(&udev->dev, "Enter\n");
 405
 406         busid_priv = get_busid_priv(udev_busid);
 407         if (!busid_priv) {
 408                 BUG();
 409                 return;
 410         }
 411
 412         sdev = dev_get_drvdata(&udev->dev);
 413
 414         /* get stub_device */
 415         if (!sdev) {
 416                 dev_err(&udev->dev, "could not get device");
 417                 return;
 418         }
 419
 420         dev_set_drvdata(&udev->dev, NULL);
 421
 422         /*
 423          * NOTE: rx/tx threads are invoked for each usb_device.
 424          */
 425         stub_remove_files(&udev->dev);
 426
 427         /* release port */
 428         rc = usb_hub_release_port(udev->parent, udev->portnum,
 429                                   (struct usb_dev_state *) udev);
 430         if (rc) {
 431                 dev_dbg(&udev->dev, "unable to release port\n");
 432                 return;
 433         }
 434
 435         /* If usb reset is called from event handler */
 436         if (usbip_in_eh(current))
 437                 return;
 438
 439         /* shutdown the current connection */
 440         shutdown_busid(busid_priv);
 441
 442         usb_put_dev(sdev->udev);
 443
 444         /* free sdev */
 445         busid_priv->sdev = NULL;
 446         stub_device_free(sdev);
 447
 448         if (busid_priv->status == STUB_BUSID_ALLOC) {
 449                 busid_priv->status = STUB_BUSID_ADDED;
 450         } else {
 451                 busid_priv->status = STUB_BUSID_OTHER;
 452                 del_match_busid((char *)udev_busid);
 453         }
 454 }
 455
 456 #ifdef CONFIG_PM
 457
 458 /* These functions need usb_port_suspend and usb_port_resume,
 459  * which reside in drivers/usb/core/usb.h. Skip for now. */
 460
 461 static int stub_suspend(struct usb_device *udev, pm_message_t message)
 462 {
 463         dev_dbg(&udev->dev, "stub_suspend\n");
 464
 465         return 0;
 466 }
 467
 468 static int stub_resume(struct usb_device *udev, pm_message_t message)
 469 {
 470         dev_dbg(&udev->dev, "stub_resume\n");
 471
 472         return 0;
 473 }
 474
 475 #endif  /* CONFIG_PM */
 476
 477 struct usb_device_driver stub_driver = {
 478         .name           = "usbip-host",
 479         .probe          = stub_probe,
 480         .disconnect     = stub_disconnect,
 481 #ifdef CONFIG_PM
 482         .suspend        = stub_suspend,
 483         .resume         = stub_resume,
 484 #endif
 485         .supports_autosuspend   =       0,
 486 };