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 usbip_sockfd_store(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         struct task_struct *tcp_rx = NULL;
  50         struct task_struct *tcp_tx = NULL;
  51
  52         if (!sdev) {
  53                 dev_err(dev, "sdev is null\n");
  54                 return -ENODEV;
  55         }
  56
  57         rv = sscanf(buf, "%d", &sockfd);
  58         if (rv != 1)
  59                 return -EINVAL;
  60
  61         if (sockfd != -1) {
  62                 int err;
  63
  64                 dev_info(dev, "stub up\n");
  65
  66                 spin_lock_irq(&sdev->ud.lock);
  67
  68                 if (sdev->ud.status != SDEV_ST_AVAILABLE) {
  69                         dev_err(dev, "not ready\n");
  70                         goto err;
  71                 }
  72
  73                 socket = sockfd_lookup(sockfd, &err);
  74                 if (!socket) {
  75                         dev_err(dev, "failed to lookup sock");
  76                         goto err;
  77                 }
  78
  79                 if (socket->type != SOCK_STREAM) {
  80                         dev_err(dev, "Expecting SOCK_STREAM - found %d",
  81                                 socket->type);
  82                         goto sock_err;
  83                 }
  84
  85                 /* unlock and create threads and get tasks */
  86                 spin_unlock_irq(&sdev->ud.lock);
  87                 tcp_rx = kthread_create(stub_rx_loop, &sdev->ud, "stub_rx");
  88                 if (IS_ERR(tcp_rx)) {
  89                         sockfd_put(socket);
  90                         return -EINVAL;
  91                 }
  92                 tcp_tx = kthread_create(stub_tx_loop, &sdev->ud, "stub_tx");
  93                 if (IS_ERR(tcp_tx)) {
  94                         kthread_stop(tcp_rx);
  95                         sockfd_put(socket);
  96                         return -EINVAL;
  97                 }
  98
  99                 /* get task structs now */
 100                 get_task_struct(tcp_rx);
 101                 get_task_struct(tcp_tx);
 102
 103                 /* lock and update sdev->ud state */
 104                 spin_lock_irq(&sdev->ud.lock);
 105                 sdev->ud.tcp_socket = socket;
 106                 sdev->ud.sockfd = sockfd;
 107                 sdev->ud.tcp_rx = tcp_rx;
 108                 sdev->ud.tcp_tx = tcp_tx;
 109                 sdev->ud.status = SDEV_ST_USED;
 110                 spin_unlock_irq(&sdev->ud.lock);
 111
 112                 wake_up_process(sdev->ud.tcp_rx);
 113                 wake_up_process(sdev->ud.tcp_tx);
 114
 115         } else {
 116                 dev_info(dev, "stub down\n");
 117
 118                 spin_lock_irq(&sdev->ud.lock);
 119                 if (sdev->ud.status != SDEV_ST_USED)
 120                         goto err;
 121
 122                 spin_unlock_irq(&sdev->ud.lock);
 123
 124                 usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN);
 125         }
 126
 127         return count;
 128
 129 sock_err:
 130         sockfd_put(socket);
 131 err:
 132         spin_unlock_irq(&sdev->ud.lock);
 133         return -EINVAL;
 134 }
 135 static DEVICE_ATTR_WO(usbip_sockfd);
 136
 137 static struct attribute *usbip_attrs[] = {
 138         &dev_attr_usbip_status.attr,
 139         &dev_attr_usbip_sockfd.attr,
 140         &dev_attr_usbip_debug.attr,
 141         NULL,
 142 };
 143 ATTRIBUTE_GROUPS(usbip);
 144
 145 static void stub_shutdown_connection(struct usbip_device *ud)
 146 {
 147         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 148
 149         /*
 150          * When removing an exported device, kernel panic sometimes occurred
 151          * and then EIP was sk_wait_data of stub_rx thread. Is this because
 152          * sk_wait_data returned though stub_rx thread was already finished by
 153          * step 1?
 154          */
 155         if (ud->tcp_socket) {
 156                 dev_dbg(&sdev->udev->dev, "shutdown sockfd %d\n", ud->sockfd);
 157                 kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
 158         }
 159
 160         /* 1. stop threads */
 161         if (ud->tcp_rx) {
 162                 kthread_stop_put(ud->tcp_rx);
 163                 ud->tcp_rx = NULL;
 164         }
 165         if (ud->tcp_tx) {
 166                 kthread_stop_put(ud->tcp_tx);
 167                 ud->tcp_tx = NULL;
 168         }
 169
 170         /*
 171          * 2. close the socket
 172          *
 173          * tcp_socket is freed after threads are killed so that usbip_xmit does
 174          * not touch NULL socket.
 175          */
 176         if (ud->tcp_socket) {
 177                 sockfd_put(ud->tcp_socket);
 178                 ud->tcp_socket = NULL;
 179                 ud->sockfd = -1;
 180         }
 181
 182         /* 3. free used data */
 183         stub_device_cleanup_urbs(sdev);
 184
 185         /* 4. free stub_unlink */
 186         {
 187                 unsigned long flags;
 188                 struct stub_unlink *unlink, *tmp;
 189
 190                 spin_lock_irqsave(&sdev->priv_lock, flags);
 191                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
 192                         list_del(&unlink->list);
 193                         kfree(unlink);
 194                 }
 195                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free,
 196                                          list) {
 197                         list_del(&unlink->list);
 198                         kfree(unlink);
 199                 }
 200                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 201         }
 202 }
 203
 204 static void stub_device_reset(struct usbip_device *ud)
 205 {
 206         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 207         struct usb_device *udev = sdev->udev;
 208         int ret;
 209
 210         dev_dbg(&udev->dev, "device reset");
 211
 212         ret = usb_lock_device_for_reset(udev, NULL);
 213         if (ret < 0) {
 214                 dev_err(&udev->dev, "lock for reset\n");
 215                 spin_lock_irq(&ud->lock);
 216                 ud->status = SDEV_ST_ERROR;
 217                 spin_unlock_irq(&ud->lock);
 218                 return;
 219         }
 220
 221         /* try to reset the device */
 222         ret = usb_reset_device(udev);
 223         usb_unlock_device(udev);
 224
 225         spin_lock_irq(&ud->lock);
 226         if (ret) {
 227                 dev_err(&udev->dev, "device reset\n");
 228                 ud->status = SDEV_ST_ERROR;
 229         } else {
 230                 dev_info(&udev->dev, "device reset\n");
 231                 ud->status = SDEV_ST_AVAILABLE;
 232         }
 233         spin_unlock_irq(&ud->lock);
 234 }
 235
 236 static void stub_device_unusable(struct usbip_device *ud)
 237 {
 238         spin_lock_irq(&ud->lock);
 239         ud->status = SDEV_ST_ERROR;
 240         spin_unlock_irq(&ud->lock);
 241 }
 242
 243 /**
 244  * stub_device_alloc - allocate a new stub_device struct
 245  * @udev: usb_device of a new device
 246  *
 247  * Allocates and initializes a new stub_device struct.
 248  */
 249 static struct stub_device *stub_device_alloc(struct usb_device *udev)
 250 {
 251         struct stub_device *sdev;
 252         int busnum = udev->bus->busnum;
 253         int devnum = udev->devnum;
 254
 255         dev_dbg(&udev->dev, "allocating stub device");
 256
 257         /* yes, it's a new device */
 258         sdev = kzalloc(sizeof(struct stub_device), GFP_KERNEL);
 259         if (!sdev)
 260                 return NULL;
 261
 262         sdev->udev = usb_get_dev(udev);
 263
 264         /*
 265          * devid is defined with devnum when this driver is first allocated.
 266          * devnum may change later if a device is reset. However, devid never
 267          * changes during a usbip connection.
 268          */
 269         sdev->devid             = (busnum << 16) | devnum;
 270         sdev->ud.side           = USBIP_STUB;
 271         sdev->ud.status         = SDEV_ST_AVAILABLE;
 272         spin_lock_init(&sdev->ud.lock);
 273         sdev->ud.tcp_socket     = NULL;
 274         sdev->ud.sockfd         = -1;
 275
 276         INIT_LIST_HEAD(&sdev->priv_init);
 277         INIT_LIST_HEAD(&sdev->priv_tx);
 278         INIT_LIST_HEAD(&sdev->priv_free);
 279         INIT_LIST_HEAD(&sdev->unlink_free);
 280         INIT_LIST_HEAD(&sdev->unlink_tx);
 281         spin_lock_init(&sdev->priv_lock);
 282
 283         init_waitqueue_head(&sdev->tx_waitq);
 284
 285         sdev->ud.eh_ops.shutdown = stub_shutdown_connection;
 286         sdev->ud.eh_ops.reset    = stub_device_reset;
 287         sdev->ud.eh_ops.unusable = stub_device_unusable;
 288
 289         usbip_start_eh(&sdev->ud);
 290
 291         dev_dbg(&udev->dev, "register new device\n");
 292
 293         return sdev;
 294 }
 295
 296 static void stub_device_free(struct stub_device *sdev)
 297 {
 298         kfree(sdev);
 299 }
 300
 301 static int stub_probe(struct usb_device *udev)
 302 {
 303         struct stub_device *sdev = NULL;
 304         const char *udev_busid = dev_name(&udev->dev);
 305         struct bus_id_priv *busid_priv;
 306         int rc = 0;
 307         char save_status;
 308
 309         dev_dbg(&udev->dev, "Enter probe\n");
 310
 311         /* Not sure if this is our device. Allocate here to avoid
 312          * calling alloc while holding busid_table lock.
 313          */
 314         sdev = stub_device_alloc(udev);
 315         if (!sdev)
 316                 return -ENOMEM;
 317
 318         /* check we should claim or not by busid_table */
 319         busid_priv = get_busid_priv(udev_busid);
 320         if (!busid_priv || (busid_priv->status == STUB_BUSID_REMOV) ||
 321             (busid_priv->status == STUB_BUSID_OTHER)) {
 322                 dev_info(&udev->dev,
 323                         "%s is not in match_busid table... skip!\n",
 324                         udev_busid);
 325
 326                 /*
 327                  * Return value should be ENODEV or ENOXIO to continue trying
 328                  * other matched drivers by the driver core.
 329                  * See driver_probe_device() in driver/base/dd.c
 330                  */
 331                 rc = -ENODEV;
 332                 if (!busid_priv)
 333                         goto sdev_free;
 334
 335                 goto call_put_busid_priv;
 336         }
 337
 338         if (udev->descriptor.bDeviceClass == USB_CLASS_HUB) {
 339                 dev_dbg(&udev->dev, "%s is a usb hub device... skip!\n",
 340                          udev_busid);
 341                 rc = -ENODEV;
 342                 goto call_put_busid_priv;
 343         }
 344
 345         if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
 346                 dev_dbg(&udev->dev,
 347                         "%s is attached on vhci_hcd... skip!\n",
 348                         udev_busid);
 349
 350                 rc = -ENODEV;
 351                 goto call_put_busid_priv;
 352         }
 353
 354
 355         dev_info(&udev->dev,
 356                 "usbip-host: register new device (bus %u dev %u)\n",
 357                 udev->bus->busnum, udev->devnum);
 358
 359         busid_priv->shutdown_busid = 0;
 360
 361         /* set private data to usb_device */
 362         dev_set_drvdata(&udev->dev, sdev);
 363
 364         busid_priv->sdev = sdev;
 365         busid_priv->udev = udev;
 366
 367         save_status = busid_priv->status;
 368         busid_priv->status = STUB_BUSID_ALLOC;
 369
 370         /* release the busid_lock */
 371         put_busid_priv(busid_priv);
 372
 373         /*
 374          * Claim this hub port.
 375          * It doesn't matter what value we pass as owner
 376          * (struct dev_state) as long as it is unique.
 377          */
 378         rc = usb_hub_claim_port(udev->parent, udev->portnum,
 379                         (struct usb_dev_state *) udev);
 380         if (rc) {
 381                 dev_dbg(&udev->dev, "unable to claim port\n");
 382                 goto err_port;
 383         }
 384
 385         return 0;
 386
 387 err_port:
 388         dev_set_drvdata(&udev->dev, NULL);
 389         usb_put_dev(udev);
 390
 391         /* we already have busid_priv, just lock busid_lock */
 392         spin_lock(&busid_priv->busid_lock);
 393         busid_priv->sdev = NULL;
 394         busid_priv->status = save_status;
 395         spin_unlock(&busid_priv->busid_lock);
 396         /* lock is released - go to free */
 397         goto sdev_free;
 398
 399 call_put_busid_priv:
 400         /* release the busid_lock */
 401         put_busid_priv(busid_priv);
 402
 403 sdev_free:
 404         stub_device_free(sdev);
 405
 406         return rc;
 407 }
 408
 409 static void shutdown_busid(struct bus_id_priv *busid_priv)
 410 {
 411         usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);
 412
 413         /* wait for the stop of the event handler */
 414         usbip_stop_eh(&busid_priv->sdev->ud);
 415 }
 416
 417 /*
 418  * called in usb_disconnect() or usb_deregister()
 419  * but only if actconfig(active configuration) exists
 420  */
 421 static void stub_disconnect(struct usb_device *udev)
 422 {
 423         struct stub_device *sdev;
 424         const char *udev_busid = dev_name(&udev->dev);
 425         struct bus_id_priv *busid_priv;
 426         int rc;
 427
 428         dev_dbg(&udev->dev, "Enter disconnect\n");
 429
 430         busid_priv = get_busid_priv(udev_busid);
 431         if (!busid_priv) {
 432                 BUG();
 433                 return;
 434         }
 435
 436         sdev = dev_get_drvdata(&udev->dev);
 437
 438         /* get stub_device */
 439         if (!sdev) {
 440                 dev_err(&udev->dev, "could not get device");
 441                 /* release busid_lock */
 442                 put_busid_priv(busid_priv);
 443                 return;
 444         }
 445
 446         dev_set_drvdata(&udev->dev, NULL);
 447
 448         /* release busid_lock before call to remove device files */
 449         put_busid_priv(busid_priv);
 450
 451         /*
 452          * NOTE: rx/tx threads are invoked for each usb_device.
 453          */
 454
 455         /* release port */
 456         rc = usb_hub_release_port(udev->parent, udev->portnum,
 457                                   (struct usb_dev_state *) udev);
 458         if (rc) {
 459                 dev_dbg(&udev->dev, "unable to release port\n");
 460                 return;
 461         }
 462
 463         /* If usb reset is called from event handler */
 464         if (usbip_in_eh(current))
 465                 return;
 466
 467         /* we already have busid_priv, just lock busid_lock */
 468         spin_lock(&busid_priv->busid_lock);
 469         if (!busid_priv->shutdown_busid)
 470                 busid_priv->shutdown_busid = 1;
 471         /* release busid_lock */
 472         spin_unlock(&busid_priv->busid_lock);
 473
 474         /* shutdown the current connection */
 475         shutdown_busid(busid_priv);
 476
 477         usb_put_dev(sdev->udev);
 478
 479         /* we already have busid_priv, just lock busid_lock */
 480         spin_lock(&busid_priv->busid_lock);
 481         /* free sdev */
 482         busid_priv->sdev = NULL;
 483         stub_device_free(sdev);
 484
 485         if (busid_priv->status == STUB_BUSID_ALLOC)
 486                 busid_priv->status = STUB_BUSID_ADDED;
 487         /* release busid_lock */
 488         spin_unlock(&busid_priv->busid_lock);
 489         return;
 490 }
 491
 492 #ifdef CONFIG_PM
 493
 494 /* These functions need usb_port_suspend and usb_port_resume,
 495  * which reside in drivers/usb/core/usb.h. Skip for now. */
 496
 497 static int stub_suspend(struct usb_device *udev, pm_message_t message)
 498 {
 499         dev_dbg(&udev->dev, "stub_suspend\n");
 500
 501         return 0;
 502 }
 503
 504 static int stub_resume(struct usb_device *udev, pm_message_t message)
 505 {
 506         dev_dbg(&udev->dev, "stub_resume\n");
 507
 508         return 0;
 509 }
 510
 511 #endif  /* CONFIG_PM */
 512
 513 struct usb_device_driver stub_driver = {
 514         .name           = "usbip-host",
 515         .probe          = stub_probe,
 516         .disconnect     = stub_disconnect,
 517 #ifdef CONFIG_PM
 518         .suspend        = stub_suspend,
 519         .resume         = stub_resume,
 520 #endif
 521         .supports_autosuspend   =       0,
 522         .dev_groups     = usbip_groups,
 523 };