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stub_dev.c

/*
 * $Id: stub_dev.c 66 2008-04-20 13:19:42Z hirofuchi $
 *
 * Copyright (C) 2003-2008 Takahiro Hirofuchi
 *
 *
 * This is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
 * USA.
 */

#include "usbip_common.h"
#include "stub.h"



static int stub_probe(struct usb_interface *interface,  const struct usb_device_id *id);
static void stub_disconnect(struct usb_interface *interface);


/*
 * Define device IDs here if you want to explicitly limit exportable devices.
 * In the most cases, wild card matching will be ok because driver binding can
 * be changed dynamically by a userland program.
 */
static struct usb_device_id stub_table[] = {
#if 0
      /* just an example */
      { USB_DEVICE(0x05ac, 0x0301) },   /* Mac 1 button mouse */
      { USB_DEVICE(0x0430, 0x0009) },   /* Plat Home Keyboard */
      { USB_DEVICE(0x059b, 0x0001) },   /* Iomega USB Zip 100 */
      { USB_DEVICE(0x04b3, 0x4427) },   /* IBM USB CD-ROM */
      { USB_DEVICE(0x05a9, 0xa511) },   /* LifeView USB cam */
      { USB_DEVICE(0x55aa, 0x0201) },   /* Imation card reader */
      { USB_DEVICE(0x046d, 0x0870) },   /* Qcam Express(QV-30) */
      { USB_DEVICE(0x04bb, 0x0101) },   /* IO-DATA HD 120GB */
      { USB_DEVICE(0x04bb, 0x0904) },   /* IO-DATA USB-ET/TX */
      { USB_DEVICE(0x04bb, 0x0201) },   /* IO-DATA USB-ET/TX */
      { USB_DEVICE(0x08bb, 0x2702) },   /* ONKYO USB Speaker */
      { USB_DEVICE(0x046d, 0x08b2) },   /* Logicool Qcam 4000 Pro */
#endif
      /* magic for wild card */
      { .driver_info = 1 },
      { }                                     /* Terminating entry */
};

MODULE_DEVICE_TABLE(usb, stub_table);


struct usb_driver stub_driver = {
      .name       = "usbip",

      .probe            = stub_probe,
      .disconnect = stub_disconnect,

      .id_table   = stub_table,
};



/*-------------------------------------------------------------------------*/

/* Define sysfs entries for a usbip-bound device */


/*
 * usbip_status shows status of usbip as long as this driver is bound to the
 * target device.
 */
static ssize_t show_status(struct device *dev, struct device_attribute *attr,
                     char *buf)
{
      struct stub_device *sdev = dev_get_drvdata(dev);
      int status;

      if (!sdev) {
            uerr("sdev is null\n");
            return -ENODEV;
      }

      spin_lock(&sdev->ud.lock);
      status = sdev->ud.status;
      spin_unlock(&sdev->ud.lock);

      return snprintf(buf, PAGE_SIZE, "%d\n", status);
}
static DEVICE_ATTR(usbip_status, S_IRUGO, show_status, NULL);


/*
 * usbip_sockfd gets a socket descriptor of an established TCP connection that
 * is used to transfer usbip requests by kernel threads. -1 is a magic number
 * by which usbip connection is finished.
 */
static ssize_t store_sockfd(struct device *dev, struct device_attribute *attr,
                      const char *buf, size_t count)
{
      struct stub_device *sdev = dev_get_drvdata(dev);
      int sockfd = 0;
      struct socket *socket;

      if (!sdev) {
            uerr("sdev is null\n");
            return -ENODEV;
      }

      sscanf(buf, "%d", &sockfd);

      if (sockfd != -1) {
            uinfo("stub up\n");

            spin_lock(&sdev->ud.lock);

            if (sdev->ud.status != SDEV_ST_AVAILABLE) {
                  uerr("not ready\n");
                  spin_unlock(&sdev->ud.lock);
                  return -EINVAL;
            }

            socket = sockfd_to_socket(sockfd);
            if (!socket) {
                  spin_unlock(&sdev->ud.lock);
                  return -EINVAL;
            }

#if 0
            setnodelay(socket);
            setkeepalive(socket);
            setreuse(socket);
#endif

            sdev->ud.tcp_socket = socket;

            spin_unlock(&sdev->ud.lock);

            usbip_start_threads(&sdev->ud);

            spin_lock(&sdev->ud.lock);
            sdev->ud.status = SDEV_ST_USED;
            spin_unlock(&sdev->ud.lock);

      } else {
            uinfo("stub down\n");

            spin_lock(&sdev->ud.lock);
            if (sdev->ud.status != SDEV_ST_USED) {
                  spin_unlock(&sdev->ud.lock);
                  return -EINVAL;
            }
            spin_unlock(&sdev->ud.lock);

            usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN);
      }

      return count;
}
static DEVICE_ATTR(usbip_sockfd, S_IWUSR, NULL, store_sockfd);

static int stub_add_files(struct device *dev)
{
      int err = 0;

      err = device_create_file(dev, &dev_attr_usbip_status);
      if (err)
            goto err_status;

      err = device_create_file(dev, &dev_attr_usbip_sockfd);
      if (err)
            goto err_sockfd;

      err = device_create_file(dev, &dev_attr_usbip_debug);
      if (err)
            goto err_debug;

      return 0;

err_debug:
      device_remove_file(dev, &dev_attr_usbip_sockfd);

err_sockfd:
      device_remove_file(dev, &dev_attr_usbip_status);

err_status:
      return err;
}

static void stub_remove_files(struct device *dev)
{
      device_remove_file(dev, &dev_attr_usbip_status);
      device_remove_file(dev, &dev_attr_usbip_sockfd);
      device_remove_file(dev, &dev_attr_usbip_debug);
}



/*-------------------------------------------------------------------------*/

/* Event handler functions called by an event handler thread */

static void stub_shutdown_connection(struct usbip_device *ud)
{
      struct stub_device *sdev = container_of(ud, struct stub_device, ud);

      /*
       * When removing an exported device, kernel panic sometimes occurred
       * and then EIP was sk_wait_data of stub_rx thread. Is this because
       * sk_wait_data returned though stub_rx thread was already finished by
       * step 1?
       */
      if (ud->tcp_socket) {
            udbg("shutdown tcp_socket %p\n", ud->tcp_socket);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24)
            /* in /usr/include/sys/socket.c, SHUT_RDWR is defined as 2. */
            ud->tcp_socket->ops->shutdown(ud->tcp_socket, 2);
#else
            kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
#endif
      }

      /* 1. stop threads */
      usbip_stop_threads(ud);

      /* 2. close the socket */
      /*
       * tcp_socket is freed after threads are killed.
       * So usbip_xmit do not touch NULL socket.
       */
      if (ud->tcp_socket) {
            sock_release(ud->tcp_socket);
            ud->tcp_socket = NULL;
      }

      /* 3. free used data */
      stub_device_cleanup_urbs(sdev);

      /* 4. free stub_unlink */
      {
            unsigned long flags;
            struct stub_unlink *unlink, *tmp;

            spin_lock_irqsave(&sdev->priv_lock, flags);

            list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
                  list_del(&unlink->list);
                  kfree(unlink);
            }

            list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free, list) {
                  list_del(&unlink->list);
                  kfree(unlink);
            }

            spin_unlock_irqrestore(&sdev->priv_lock, flags);
      }
}

static void stub_device_reset(struct usbip_device *ud)
{
      struct stub_device *sdev = container_of(ud, struct stub_device, ud);
      struct usb_device *udev = interface_to_usbdev(sdev->interface);
      int ret;

      udbg("device reset");
      ret = usb_lock_device_for_reset(udev, sdev->interface);
      if (ret < 0) {
            uerr("lock for reset\n");

            spin_lock(&ud->lock);
            ud->status = SDEV_ST_ERROR;
            spin_unlock(&ud->lock);

            return;
      }

      /* try to reset the device */
      ret = usb_reset_device(udev);

      usb_unlock_device(udev);

      spin_lock(&ud->lock);
      if (ret) {
            uerr("device reset\n");
            ud->status = SDEV_ST_ERROR;

      } else {
            uinfo("device reset\n");
            ud->status = SDEV_ST_AVAILABLE;

      }
      spin_unlock(&ud->lock);

      return;
}

static void stub_device_unusable(struct usbip_device *ud)
{
      spin_lock(&ud->lock);
      ud->status = SDEV_ST_ERROR;
      spin_unlock(&ud->lock);
}


/*-------------------------------------------------------------------------*/

/**
 * stub_device_alloc - allocate a new stub_device struct
 * @interface: usb_interface of a new device
 *
 * Allocates and initializes a new stub_device struct.
 */
static struct stub_device * stub_device_alloc(struct usb_interface *interface)
{
      struct stub_device *sdev;
      int busnum = interface_to_busnum(interface);
      int devnum = interface_to_devnum(interface);

      udbg("allocating stub device");
      /* yes, it's a new device */
      sdev = (struct stub_device *) kzalloc(sizeof(struct stub_device), GFP_KERNEL);
      if (!sdev) {
            uerr("no memory for stub_device\n");
            return NULL;
      }

      sdev->interface = interface;

      /*
       * devid is defined with devnum when this driver is first allocated.
       * devnum may change later if a device is reset. However, devid never
       * changes during a usbip connection.
       */
      sdev->devid     = (busnum << 16) | devnum;

      usbip_task_init(&sdev->ud.tcp_rx, "stub_rx", stub_rx_loop);
      usbip_task_init(&sdev->ud.tcp_tx, "stub_tx", stub_tx_loop);

      sdev->ud.side = USBIP_STUB;
      sdev->ud.status = SDEV_ST_AVAILABLE;
      // sdev->ud.lock = SPIN_LOCK_UNLOCKED;
      spin_lock_init(&sdev->ud.lock);
      sdev->ud.tcp_socket = NULL;

      INIT_LIST_HEAD(&sdev->priv_init);
      INIT_LIST_HEAD(&sdev->priv_tx);
      INIT_LIST_HEAD(&sdev->priv_free);
      INIT_LIST_HEAD(&sdev->unlink_free);
      INIT_LIST_HEAD(&sdev->unlink_tx);
      // sdev->priv_lock = SPIN_LOCK_UNLOCKED;
      spin_lock_init(&sdev->priv_lock);

      init_waitqueue_head(&sdev->tx_waitq);

      sdev->ud.eh_ops.shutdown = stub_shutdown_connection;
      sdev->ud.eh_ops.reset    = stub_device_reset;
      sdev->ud.eh_ops.unusable = stub_device_unusable;

      usbip_start_eh(&sdev->ud);

      udbg("register new interface\n");
      return sdev;
}

static int stub_device_free(struct stub_device *sdev)
{
      if (!sdev)
            return -EINVAL;

      kfree(sdev);
      udbg("kfree udev ok\n");

      return 0;
}


/*-------------------------------------------------------------------------*/

/*
 * If a usb device has multiple active interfaces, this driver is bound to all
 * the active interfaces. However, usbip exports *a* usb device (i.e., not *an*
 * active interface). Currently, a userland program must ensure that it
 * looks at the usbip's sysfs entries of only the first active interface.
 *
 * TODO: use "struct usb_device_driver" to bind a usb device.
 * However, it seems it is not fully supported in mainline kernel yet (2.6.19.2).
 */
static int stub_probe(struct usb_interface *interface, const struct usb_device_id *id)
{
      struct usb_device *udev = interface_to_usbdev(interface);
      struct stub_device *sdev = NULL;
      char *udev_busid = interface->dev.parent->bus_id;
      int err = 0;

      udbg("Enter\n");

      /* check we should claim or not by busid_table */
      if (match_busid(udev_busid)) {
            uinfo("this device %s is not in match_busid table. skip!\n", udev_busid);

            /*
             * Return value should be ENODEV or ENOXIO to continue trying
             * other matched drivers by the driver core.
             * See driver_probe_device() in driver/base/dd.c
             */
            return -ENODEV;
      }

      if (udev->descriptor.bDeviceClass ==  USB_CLASS_HUB) {
            udbg("this device %s is a usb hub device. skip!\n", udev_busid);
            return -ENODEV;
      }

      if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
            udbg("this device %s is attached on vhci_hcd. skip!\n", udev_busid);
            return -ENODEV;
      }

      /* ok. this is my device. */

      if ((sdev = stub_device_alloc(interface))) {
            struct usb_device *udev = interface_to_usbdev(interface);

            uinfo("USB/IP Stub: register a new interface (bus %u dev %u ifn %u)\n",
                        udev->bus->busnum, udev->devnum,
                        interface->cur_altsetting->desc.bInterfaceNumber);
      } else
            return -ENOMEM;

      /* set private data to usb_interface */
      usb_set_intfdata(interface, sdev);

      err = stub_add_files(&interface->dev);
      if (err) {
            uerr("create sysfs files for %s\n", udev_busid);
            return err;
      }

      return 0;
}


/*
 * called in usb_disconnect() or usb_deregister()
 * but only if actconfig(active configuration) exists
 */
static void stub_disconnect(struct usb_interface *interface)
{
      struct stub_device *sdev = usb_get_intfdata(interface);

      udbg("Enter\n");

      /* get stub_device */
      if (!sdev) {
            err(" could not get device from inteface data");
            //BUG();
            return;
      }

      usb_set_intfdata(interface, NULL);


      /*
       * NOTE:
       * rx/tx threads are invoked for each usb_device.
       */
      stub_remove_files(&interface->dev);

      /* 1. shutdown the current connection */
      usbip_event_add(&sdev->ud, SDEV_EVENT_REMOVED);

      /* 2. wait for the stop of the event handler */
      usbip_stop_eh(&sdev->ud);

      /* 3. free sdev */
      stub_device_free(sdev);


      udbg("bye\n");
}

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