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