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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2018, Linaro Ltd */
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/skbuff.h>
#include <linux/uaccess.h>
#include "qrtr.h"
struct qrtr_tun {
struct qrtr_endpoint ep;
struct sk_buff_head queue;
wait_queue_head_t readq;
};
static int qrtr_tun_send(struct qrtr_endpoint *ep, struct sk_buff *skb)
{
struct qrtr_tun *tun = container_of(ep, struct qrtr_tun, ep);
skb_queue_tail(&tun->queue, skb);
/* wake up any blocking processes, waiting for new data */
wake_up_interruptible(&tun->readq);
return 0;
}
static int qrtr_tun_open(struct inode *inode, struct file *filp)
{
struct qrtr_tun *tun;
int ret;
tun = kzalloc(sizeof(*tun), GFP_KERNEL);
if (!tun)
return -ENOMEM;
skb_queue_head_init(&tun->queue);
init_waitqueue_head(&tun->readq);
tun->ep.xmit = qrtr_tun_send;
filp->private_data = tun;
ret = qrtr_endpoint_register(&tun->ep, QRTR_EP_NID_AUTO);
if (ret)
goto out;
return 0;
out:
filp->private_data = NULL;
kfree(tun);
return ret;
}
static ssize_t qrtr_tun_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct file *filp = iocb->ki_filp;
struct qrtr_tun *tun = filp->private_data;
struct sk_buff *skb;
int count;
while (!(skb = skb_dequeue(&tun->queue))) {
if (filp->f_flags & O_NONBLOCK)
return -EAGAIN;
/* Wait until we get data or the endpoint goes away */
if (wait_event_interruptible(tun->readq,
!skb_queue_empty(&tun->queue)))
return -ERESTARTSYS;
}
count = min_t(size_t, iov_iter_count(to), skb->len);
if (copy_to_iter(skb->data, count, to) != count)
count = -EFAULT;
kfree_skb(skb);
return count;
}
static ssize_t qrtr_tun_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *filp = iocb->ki_filp;
struct qrtr_tun *tun = filp->private_data;
size_t len = iov_iter_count(from);
ssize_t ret;
void *kbuf;
if (!len)
return -EINVAL;
if (len > KMALLOC_MAX_SIZE)
return -ENOMEM;
kbuf = kzalloc(len, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
if (!copy_from_iter_full(kbuf, len, from)) {
kfree(kbuf);
return -EFAULT;
}
ret = qrtr_endpoint_post(&tun->ep, kbuf, len);
kfree(kbuf);
return ret < 0 ? ret : len;
}
static __poll_t qrtr_tun_poll(struct file *filp, poll_table *wait)
{
struct qrtr_tun *tun = filp->private_data;
__poll_t mask = 0;
poll_wait(filp, &tun->readq, wait);
if (!skb_queue_empty(&tun->queue))
mask |= EPOLLIN | EPOLLRDNORM;
return mask;
}
static int qrtr_tun_release(struct inode *inode, struct file *filp)
{
struct qrtr_tun *tun = filp->private_data;
qrtr_endpoint_unregister(&tun->ep);
/* Discard all SKBs */
skb_queue_purge(&tun->queue);
kfree(tun);
return 0;
}
static const struct file_operations qrtr_tun_ops = {
.owner = THIS_MODULE,
.open = qrtr_tun_open,
.poll = qrtr_tun_poll,
.read_iter = qrtr_tun_read_iter,
.write_iter = qrtr_tun_write_iter,
.release = qrtr_tun_release,
};
static struct miscdevice qrtr_tun_miscdev = {
MISC_DYNAMIC_MINOR,
"qrtr-tun",
&qrtr_tun_ops,
};
static int __init qrtr_tun_init(void)
{
int ret;
ret = misc_register(&qrtr_tun_miscdev);
if (ret)
pr_err("failed to register Qualcomm IPC Router tun device\n");
return ret;
}
static void __exit qrtr_tun_exit(void)
{
misc_deregister(&qrtr_tun_miscdev);
}
module_init(qrtr_tun_init);
module_exit(qrtr_tun_exit);
MODULE_DESCRIPTION("Qualcomm IPC Router TUN device");
MODULE_LICENSE("GPL v2");
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