// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2003-2008 Takahiro Hirofuchi
 * Copyright (C) 2015-2016 Nobuo Iwata
 */

#include <linux/kthread.h>
#include <linux/file.h>
#include <linux/net.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

/* Hardening for Spectre-v1 */
#include <linux/nospec.h>

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

/* TODO: refine locking ?*/

/*
 * output example:
 * hub port sta spd dev       sockfd local_busid
 * hs  0000 004 000 00000000  000003 1-2.3
 * ................................................
 * ss  0008 004 000 00000000  000004 2-3.4
 * ................................................
 *
 * Output includes socket fd instead of socket pointer address to avoid
 * leaking kernel memory address in:
 *      /sys/devices/platform/vhci_hcd.0/status and in debug output.
 * The socket pointer address is not used at the moment and it was made
 * visible as a convenient way to find IP address from socket pointer
 * address by looking up /proc/net/{tcp,tcp6}. As this opens a security
 * hole, the change is made to use sockfd instead.
 *
 */
static void port_show_vhci(char **out, int hub, int port, struct vhci_device *vdev)
{
        if (hub == HUB_SPEED_HIGH)
                *out += sprintf(*out, "hs  %04u %03u ",
                                      port, vdev->ud.status);
        else /* hub == HUB_SPEED_SUPER */
                *out += sprintf(*out, "ss  %04u %03u ",
                                      port, vdev->ud.status);

        if (vdev->ud.status == VDEV_ST_USED) {
                *out += sprintf(*out, "%03u %08x ",
                                      vdev->speed, vdev->devid);
                *out += sprintf(*out, "%06u %s",
                                      vdev->ud.sockfd,
                                      dev_name(&vdev->udev->dev));

        } else {
                *out += sprintf(*out, "000 00000000 ");
                *out += sprintf(*out, "000000 0-0");
        }

        *out += sprintf(*out, "\n");
}

/* Sysfs entry to show port status */
static ssize_t status_show_vhci(int pdev_nr, char *out)
{
        struct platform_device *pdev = vhcis[pdev_nr].pdev;
        struct vhci *vhci;
        struct usb_hcd *hcd;
        struct vhci_hcd *vhci_hcd;
        char *s = out;
        int i;
        unsigned long flags;

        if (!pdev || !out) {
                usbip_dbg_vhci_sysfs("show status error\n");
                return 0;
        }

        hcd = platform_get_drvdata(pdev);
        vhci_hcd = hcd_to_vhci_hcd(hcd);
        vhci = vhci_hcd->vhci;

        spin_lock_irqsave(&vhci->lock, flags);

        for (i = 0; i < VHCI_HC_PORTS; i++) {
                struct vhci_device *vdev = &vhci->vhci_hcd_hs->vdev[i];

                spin_lock(&vdev->ud.lock);
                port_show_vhci(&out, HUB_SPEED_HIGH,
                               pdev_nr * VHCI_PORTS + i, vdev);
                spin_unlock(&vdev->ud.lock);
        }

        for (i = 0; i < VHCI_HC_PORTS; i++) {
                struct vhci_device *vdev = &vhci->vhci_hcd_ss->vdev[i];

                spin_lock(&vdev->ud.lock);
                port_show_vhci(&out, HUB_SPEED_SUPER,
                               pdev_nr * VHCI_PORTS + VHCI_HC_PORTS + i, vdev);
                spin_unlock(&vdev->ud.lock);
        }

        spin_unlock_irqrestore(&vhci->lock, flags);

        return out - s;
}

static ssize_t status_show_not_ready(int pdev_nr, char *out)
{
        char *s = out;
        int i = 0;

        for (i = 0; i < VHCI_HC_PORTS; i++) {
                out += sprintf(out, "hs  %04u %03u ",
                                    (pdev_nr * VHCI_PORTS) + i,
                                    VDEV_ST_NOTASSIGNED);
                out += sprintf(out, "000 00000000 0000000000000000 0-0");
                out += sprintf(out, "\n");
        }

        for (i = 0; i < VHCI_HC_PORTS; i++) {
                out += sprintf(out, "ss  %04u %03u ",
                                    (pdev_nr * VHCI_PORTS) + VHCI_HC_PORTS + i,
                                    VDEV_ST_NOTASSIGNED);
                out += sprintf(out, "000 00000000 0000000000000000 0-0");
                out += sprintf(out, "\n");
        }
        return out - s;
}

static int status_name_to_id(const char *name)
{
        char *c;
        long val;
        int ret;

        c = strchr(name, '.');
        if (c == NULL)
                return 0;

        ret = kstrtol(c+1, 10, &val);
        if (ret < 0)
                return ret;

        return val;
}

static ssize_t status_show(struct device *dev,
                           struct device_attribute *attr, char *out)
{
        char *s = out;
        int pdev_nr;

        out += sprintf(out,
                       "hub port sta spd dev      sockfd local_busid\n");

        pdev_nr = status_name_to_id(attr->attr.name);
        if (pdev_nr < 0)
                out += status_show_not_ready(pdev_nr, out);
        else
                out += status_show_vhci(pdev_nr, out);

        return out - s;
}

static ssize_t nports_show(struct device *dev, struct device_attribute *attr,
                           char *out)
{
        char *s = out;

        /*
         * Half the ports are for SPEED_HIGH and half for SPEED_SUPER,
         * thus the * 2.
         */
        out += sprintf(out, "%d\n", VHCI_PORTS * vhci_num_controllers);
        return out - s;
}
static DEVICE_ATTR_RO(nports);

/* Sysfs entry to shutdown a virtual connection */
static int vhci_port_disconnect(struct vhci_hcd *vhci_hcd, __u32 rhport)
{
        struct vhci_device *vdev = &vhci_hcd->vdev[rhport];
        struct vhci *vhci = vhci_hcd->vhci;
        unsigned long flags;

        usbip_dbg_vhci_sysfs("enter\n");

        mutex_lock(&vdev->ud.sysfs_lock);

        /* lock */
        spin_lock_irqsave(&vhci->lock, flags);
        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_irqrestore(&vhci->lock, flags);
                mutex_unlock(&vdev->ud.sysfs_lock);

                return -EINVAL;
        }

        /* unlock */
        spin_unlock(&vdev->ud.lock);
        spin_unlock_irqrestore(&vhci->lock, flags);

        usbip_event_add(&vdev->ud, VDEV_EVENT_DOWN);

        mutex_unlock(&vdev->ud.sysfs_lock);

        return 0;
}

static int valid_port(__u32 *pdev_nr, __u32 *rhport)
{
        if (*pdev_nr >= vhci_num_controllers) {
                pr_err("pdev %u\n", *pdev_nr);
                return 0;
        }
        *pdev_nr = array_index_nospec(*pdev_nr, vhci_num_controllers);

        if (*rhport >= VHCI_HC_PORTS) {
                pr_err("rhport %u\n", *rhport);
                return 0;
        }
        *rhport = array_index_nospec(*rhport, VHCI_HC_PORTS);

        return 1;
}

static ssize_t detach_store(struct device *dev, struct device_attribute *attr,
                            const char *buf, size_t count)
{
        __u32 port = 0, pdev_nr = 0, rhport = 0;
        struct usb_hcd *hcd;
        struct vhci_hcd *vhci_hcd;
        int ret;

        if (kstrtoint(buf, 10, &port) < 0)
                return -EINVAL;

        pdev_nr = port_to_pdev_nr(port);
        rhport = port_to_rhport(port);

        if (!valid_port(&pdev_nr, &rhport))
                return -EINVAL;

        hcd = platform_get_drvdata(vhcis[pdev_nr].pdev);
        if (hcd == NULL) {
                dev_err(dev, "port is not ready %u\n", port);
                return -EAGAIN;
        }

        usbip_dbg_vhci_sysfs("rhport %d\n", rhport);

        if ((port / VHCI_HC_PORTS) % 2)
                vhci_hcd = hcd_to_vhci_hcd(hcd)->vhci->vhci_hcd_ss;
        else
                vhci_hcd = hcd_to_vhci_hcd(hcd)->vhci->vhci_hcd_hs;

        ret = vhci_port_disconnect(vhci_hcd, rhport);
        if (ret < 0)
                return -EINVAL;

        usbip_dbg_vhci_sysfs("Leave\n");

        return count;
}
static DEVICE_ATTR_WO(detach);

static int valid_args(__u32 *pdev_nr, __u32 *rhport,
                      enum usb_device_speed speed)
{
        if (!valid_port(pdev_nr, rhport)) {
                return 0;
        }

        switch (speed) {
        case USB_SPEED_LOW:
        case USB_SPEED_FULL:
        case USB_SPEED_HIGH:
        case USB_SPEED_WIRELESS:
        case USB_SPEED_SUPER:
        case USB_SPEED_SUPER_PLUS:
                break;
        default:
                pr_err("Failed attach request for unsupported USB speed: %s\n",
                        usb_speed_string(speed));
                return 0;
        }

        return 1;
}

/* Sysfs entry to establish a virtual connection */
/*
 * 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 attach_store(struct device *dev, struct device_attribute *attr,
                            const char *buf, size_t count)
{
        struct socket *socket;
        int sockfd = 0;
        __u32 port = 0, pdev_nr = 0, rhport = 0, devid = 0, speed = 0;
        struct usb_hcd *hcd;
        struct vhci_hcd *vhci_hcd;
        struct vhci_device *vdev;
        struct vhci *vhci;
        int err;
        unsigned long flags;
        struct task_struct *tcp_rx = NULL;
        struct task_struct *tcp_tx = NULL;

        /*
         * @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
         */
        if (sscanf(buf, "%u %u %u %u", &port, &sockfd, &devid, &speed) != 4)
                return -EINVAL;
        pdev_nr = port_to_pdev_nr(port);
        rhport = port_to_rhport(port);

        usbip_dbg_vhci_sysfs("port(%u) pdev(%d) rhport(%u)\n",
                             port, pdev_nr, rhport);
        usbip_dbg_vhci_sysfs("sockfd(%u) devid(%u) speed(%u)\n",
                             sockfd, devid, speed);

        /* check received parameters */
        if (!valid_args(&pdev_nr, &rhport, speed))
                return -EINVAL;

        hcd = platform_get_drvdata(vhcis[pdev_nr].pdev);
        if (hcd == NULL) {
                dev_err(dev, "port %d is not ready\n", port);
                return -EAGAIN;
        }

        vhci_hcd = hcd_to_vhci_hcd(hcd);
        vhci = vhci_hcd->vhci;

        if (speed >= USB_SPEED_SUPER)
                vdev = &vhci->vhci_hcd_ss->vdev[rhport];
        else
                vdev = &vhci->vhci_hcd_hs->vdev[rhport];

        mutex_lock(&vdev->ud.sysfs_lock);

        /* Extract socket from fd. */
        socket = sockfd_lookup(sockfd, &err);
        if (!socket) {
                dev_err(dev, "failed to lookup sock");
                err = -EINVAL;
                goto unlock_mutex;
        }
        if (socket->type != SOCK_STREAM) {
                dev_err(dev, "Expecting SOCK_STREAM - found %d",
                        socket->type);
                sockfd_put(socket);
                err = -EINVAL;
                goto unlock_mutex;
        }

        /* create threads before locking */
        tcp_rx = kthread_create(vhci_rx_loop, &vdev->ud, "vhci_rx");
        if (IS_ERR(tcp_rx)) {
                sockfd_put(socket);
                err = -EINVAL;
                goto unlock_mutex;
        }
        tcp_tx = kthread_create(vhci_tx_loop, &vdev->ud, "vhci_tx");
        if (IS_ERR(tcp_tx)) {
                kthread_stop(tcp_rx);
                sockfd_put(socket);
                err = -EINVAL;
                goto unlock_mutex;
        }

        /* get task structs now */
        get_task_struct(tcp_rx);
        get_task_struct(tcp_tx);

        /* now begin lock until setting vdev status set */
        spin_lock_irqsave(&vhci->lock, flags);
        spin_lock(&vdev->ud.lock);

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

                sockfd_put(socket);
                kthread_stop_put(tcp_rx);
                kthread_stop_put(tcp_tx);

                dev_err(dev, "port %d already used\n", rhport);
                /*
                 * Will be retried from userspace
                 * if there's another free port.
                 */
                err = -EBUSY;
                goto unlock_mutex;
        }

        dev_info(dev, "pdev(%u) rhport(%u) sockfd(%d)\n",
                 pdev_nr, rhport, sockfd);
        dev_info(dev, "devid(%u) speed(%u) speed_str(%s)\n",
                 devid, speed, usb_speed_string(speed));

        vdev->devid         = devid;
        vdev->speed         = speed;
        vdev->ud.sockfd     = sockfd;
        vdev->ud.tcp_socket = socket;
        vdev->ud.tcp_rx     = tcp_rx;
        vdev->ud.tcp_tx     = tcp_tx;
        vdev->ud.status     = VDEV_ST_NOTASSIGNED;
        usbip_kcov_handle_init(&vdev->ud);

        spin_unlock(&vdev->ud.lock);
        spin_unlock_irqrestore(&vhci->lock, flags);
        /* end the lock */

        wake_up_process(vdev->ud.tcp_rx);
        wake_up_process(vdev->ud.tcp_tx);

        rh_port_connect(vdev, speed);

        dev_info(dev, "Device attached\n");

        mutex_unlock(&vdev->ud.sysfs_lock);

        return count;

unlock_mutex:
        mutex_unlock(&vdev->ud.sysfs_lock);
        return err;
}
static DEVICE_ATTR_WO(attach);

#define MAX_STATUS_NAME 16

struct status_attr {
        struct device_attribute attr;
        char name[MAX_STATUS_NAME+1];
};

static struct status_attr *status_attrs;

static void set_status_attr(int id)
{
        struct status_attr *status;

        status = status_attrs + id;
        if (id == 0)
                strcpy(status->name, "status");
        else
                snprintf(status->name, MAX_STATUS_NAME+1, "status.%d", id);
        status->attr.attr.name = status->name;
        status->attr.attr.mode = S_IRUGO;
        status->attr.show = status_show;
        sysfs_attr_init(&status->attr.attr);
}

static int init_status_attrs(void)
{
        int id;

        status_attrs = kzalloc_objs(struct status_attr, vhci_num_controllers);
        if (status_attrs == NULL)
                return -ENOMEM;

        for (id = 0; id < vhci_num_controllers; id++)
                set_status_attr(id);

        return 0;
}

static void finish_status_attrs(void)
{
        kfree(status_attrs);
}

struct attribute_group vhci_attr_group = {
        .attrs = NULL,
};

int vhci_init_attr_group(void)
{
        struct attribute **attrs;
        int ret, i;

        attrs = kzalloc_objs(struct attribute *, (vhci_num_controllers + 5));
        if (attrs == NULL)
                return -ENOMEM;

        ret = init_status_attrs();
        if (ret) {
                kfree(attrs);
                return ret;
        }
        *attrs = &dev_attr_nports.attr;
        *(attrs + 1) = &dev_attr_detach.attr;
        *(attrs + 2) = &dev_attr_attach.attr;
        *(attrs + 3) = &dev_attr_usbip_debug.attr;
        for (i = 0; i < vhci_num_controllers; i++)
                *(attrs + i + 4) = &((status_attrs + i)->attr.attr);
        vhci_attr_group.attrs = attrs;
        return 0;
}

void vhci_finish_attr_group(void)
{
        finish_status_attrs();
        kfree(vhci_attr_group.attrs);
}