/*
 * 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 <linux/kthread.h>
#include <linux/file.h>
#include <linux/net.h>

#include "usbip_common.h"
#include "vhci.h"

/* TODO: refine locking ?*/

/* Sysfs entry to show port status */
static ssize_t show_status(struct device *dev, struct device_attribute *attr,
                           char *out)
{
        char *s = out;
        int i = 0;

        BUG_ON(!the_controller || !out);

        spin_lock(&the_controller->lock);

        /*
         * output example:
         * prt sta spd dev socket           local_busid
         * 000 004 000 000         c5a7bb80 1-2.3
         * 001 004 000 000         d8cee980 2-3.4
         *
         * IP address can be retrieved from a socket pointer address by looking
         * up /proc/net/{tcp,tcp6}. Also, a userland program may remember a
         * port number and its peer IP address.
         */
        out += sprintf(out, "prt sta spd bus dev socket           "
                       "local_busid\n");

        for (i = 0; i < VHCI_NPORTS; i++) {
                struct vhci_device *vdev = port_to_vdev(i);

                spin_lock(&vdev->ud.lock);
                out += sprintf(out, "%03u %03u ", i, vdev->ud.status);

                if (vdev->ud.status == VDEV_ST_USED) {
                        out += sprintf(out, "%03u %08x ",
                                       vdev->speed, vdev->devid);
                        out += sprintf(out, "%16p ", vdev->ud.tcp_socket);
                        out += sprintf(out, "%s", dev_name(&vdev->udev->dev));

                } else {
                        out += sprintf(out, "000 000 000 0000000000000000 0-0");
                }

                out += sprintf(out, "\n");
                spin_unlock(&vdev->ud.lock);
        }

        spin_unlock(&the_controller->lock);

        return out - s;
}
static DEVICE_ATTR(status, S_IRUGO, show_status, NULL);

/* Sysfs entry to shutdown a virtual connection */
static int vhci_port_disconnect(__u32 rhport)
{
        struct vhci_device *vdev;

        usbip_dbg_vhci_sysfs("enter\n");

        /* lock */
        spin_lock(&the_controller->lock);

        vdev = port_to_vdev(rhport);

        spin_lock(&vdev->ud.lock);
        if (vdev->ud.status == VDEV_ST_NULL) {
                pr_err("not connected %d\n", vdev->ud.status);

                /* unlock */
                spin_unlock(&vdev->ud.lock);
                spin_unlock(&the_controller->lock);

                return -EINVAL;
        }

        /* unlock */
        spin_unlock(&vdev->ud.lock);
        spin_unlock(&the_controller->lock);

        usbip_event_add(&vdev->ud, VDEV_EVENT_DOWN);

        return 0;
}

static ssize_t store_detach(struct device *dev, struct device_attribute *attr,
                            const char *buf, size_t count)
{
        int err;
        __u32 rhport = 0;

        sscanf(buf, "%u", &rhport);

        /* check rhport */
        if (rhport >= VHCI_NPORTS) {
                dev_err(dev, "invalid port %u\n", rhport);
                return -EINVAL;
        }

        err = vhci_port_disconnect(rhport);
        if (err < 0)
                return -EINVAL;

        usbip_dbg_vhci_sysfs("Leave\n");

        return count;
}
static DEVICE_ATTR(detach, S_IWUSR, NULL, store_detach);

/* Sysfs entry to establish a virtual connection */
static int valid_args(__u32 rhport, enum usb_device_speed speed)
{
        /* check rhport */
        if (rhport >= VHCI_NPORTS) {
                pr_err("port %u\n", rhport);
                return -EINVAL;
        }

        /* check speed */
        switch (speed) {
        case USB_SPEED_LOW:
        case USB_SPEED_FULL:
        case USB_SPEED_HIGH:
        case USB_SPEED_WIRELESS:
                break;
        default:
                pr_err("speed %d\n", speed);
                return -EINVAL;
        }

        return 0;
}

/*
 * To start a new USB/IP attachment, a userland program needs to setup a TCP
 * connection and then write its socket descriptor with remote device
 * information into this sysfs file.
 *
 * A remote device is virtually attached to the root-hub port of @rhport with
 * @speed. @devid is embedded into a request to specify the remote device in a
 * server host.
 *
 * write() returns 0 on success, else negative errno.
 */
static ssize_t store_attach(struct device *dev, struct device_attribute *attr,
                            const char *buf, size_t count)
{
        struct vhci_device *vdev;
        struct socket *socket;
        int sockfd = 0;
        __u32 rhport = 0, devid = 0, speed = 0;

        /*
         * @rhport: port number of vhci_hcd
         * @sockfd: socket descriptor of an established TCP connection
         * @devid: unique device identifier in a remote host
         * @speed: usb device speed in a remote host
         */
        sscanf(buf, "%u %u %u %u", &rhport, &sockfd, &devid, &speed);

        usbip_dbg_vhci_sysfs("rhport(%u) sockfd(%u) devid(%u) speed(%u)\n",
                             rhport, sockfd, devid, speed);

        /* check received parameters */
        if (valid_args(rhport, speed) < 0)
                return -EINVAL;

        /* Extract socket from fd. */
        /* The correct way to clean this up is to fput(socket->file). */
        socket = sockfd_to_socket(sockfd);
        if (!socket)
                return -EINVAL;

        /* now need lock until setting vdev status as used */

        /* begin a lock */
        spin_lock(&the_controller->lock);
        vdev = port_to_vdev(rhport);
        spin_lock(&vdev->ud.lock);

        if (vdev->ud.status != VDEV_ST_NULL) {
                /* end of the lock */
                spin_unlock(&vdev->ud.lock);
                spin_unlock(&the_controller->lock);

                fput(socket->file);

                dev_err(dev, "port %d already used\n", rhport);
                return -EINVAL;
        }

        dev_info(dev, "rhport(%u) sockfd(%d) devid(%u) speed(%u)\n",
                 rhport, sockfd, devid, speed);

        vdev->devid         = devid;
        vdev->speed         = speed;
        vdev->ud.tcp_socket = socket;
        vdev->ud.status     = VDEV_ST_NOTASSIGNED;

        spin_unlock(&vdev->ud.lock);
        spin_unlock(&the_controller->lock);
        /* end the lock */

        vdev->ud.tcp_rx = kthread_get_run(vhci_rx_loop, &vdev->ud, "vhci_rx");
        vdev->ud.tcp_tx = kthread_get_run(vhci_tx_loop, &vdev->ud, "vhci_tx");

        rh_port_connect(rhport, speed);

        return count;
}
static DEVICE_ATTR(attach, S_IWUSR, NULL, store_attach);

static struct attribute *dev_attrs[] = {
        &dev_attr_status.attr,
        &dev_attr_detach.attr,
        &dev_attr_attach.attr,
        &dev_attr_usbip_debug.attr,
        NULL,
};

const struct attribute_group dev_attr_group = {
        .attrs = dev_attrs,
};