Bjorn Andersson | 28fb4e5 | 2018-04-26 22:28:49 -0700 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* Copyright (c) 2018, Linaro Ltd */ |
| 3 | |
| 4 | #include <linux/miscdevice.h> |
| 5 | #include <linux/module.h> |
| 6 | #include <linux/poll.h> |
| 7 | #include <linux/skbuff.h> |
| 8 | #include <linux/uaccess.h> |
| 9 | |
| 10 | #include "qrtr.h" |
| 11 | |
| 12 | struct qrtr_tun { |
| 13 | struct qrtr_endpoint ep; |
| 14 | |
| 15 | struct sk_buff_head queue; |
| 16 | wait_queue_head_t readq; |
| 17 | }; |
| 18 | |
| 19 | static int qrtr_tun_send(struct qrtr_endpoint *ep, struct sk_buff *skb) |
| 20 | { |
| 21 | struct qrtr_tun *tun = container_of(ep, struct qrtr_tun, ep); |
| 22 | |
| 23 | skb_queue_tail(&tun->queue, skb); |
| 24 | |
| 25 | /* wake up any blocking processes, waiting for new data */ |
| 26 | wake_up_interruptible(&tun->readq); |
| 27 | |
| 28 | return 0; |
| 29 | } |
| 30 | |
| 31 | static int qrtr_tun_open(struct inode *inode, struct file *filp) |
| 32 | { |
| 33 | struct qrtr_tun *tun; |
Takeshi Misawa | fc0494e | 2021-02-22 08:44:27 +0900 | [diff] [blame] | 34 | int ret; |
Bjorn Andersson | 28fb4e5 | 2018-04-26 22:28:49 -0700 | [diff] [blame] | 35 | |
| 36 | tun = kzalloc(sizeof(*tun), GFP_KERNEL); |
| 37 | if (!tun) |
| 38 | return -ENOMEM; |
| 39 | |
| 40 | skb_queue_head_init(&tun->queue); |
| 41 | init_waitqueue_head(&tun->readq); |
| 42 | |
| 43 | tun->ep.xmit = qrtr_tun_send; |
| 44 | |
| 45 | filp->private_data = tun; |
| 46 | |
Takeshi Misawa | fc0494e | 2021-02-22 08:44:27 +0900 | [diff] [blame] | 47 | ret = qrtr_endpoint_register(&tun->ep, QRTR_EP_NID_AUTO); |
| 48 | if (ret) |
| 49 | goto out; |
| 50 | |
| 51 | return 0; |
| 52 | |
| 53 | out: |
| 54 | filp->private_data = NULL; |
| 55 | kfree(tun); |
| 56 | return ret; |
Bjorn Andersson | 28fb4e5 | 2018-04-26 22:28:49 -0700 | [diff] [blame] | 57 | } |
| 58 | |
| 59 | static ssize_t qrtr_tun_read_iter(struct kiocb *iocb, struct iov_iter *to) |
| 60 | { |
| 61 | struct file *filp = iocb->ki_filp; |
| 62 | struct qrtr_tun *tun = filp->private_data; |
| 63 | struct sk_buff *skb; |
| 64 | int count; |
| 65 | |
| 66 | while (!(skb = skb_dequeue(&tun->queue))) { |
| 67 | if (filp->f_flags & O_NONBLOCK) |
| 68 | return -EAGAIN; |
| 69 | |
| 70 | /* Wait until we get data or the endpoint goes away */ |
| 71 | if (wait_event_interruptible(tun->readq, |
| 72 | !skb_queue_empty(&tun->queue))) |
| 73 | return -ERESTARTSYS; |
| 74 | } |
| 75 | |
| 76 | count = min_t(size_t, iov_iter_count(to), skb->len); |
| 77 | if (copy_to_iter(skb->data, count, to) != count) |
| 78 | count = -EFAULT; |
| 79 | |
| 80 | kfree_skb(skb); |
| 81 | |
| 82 | return count; |
| 83 | } |
| 84 | |
| 85 | static ssize_t qrtr_tun_write_iter(struct kiocb *iocb, struct iov_iter *from) |
| 86 | { |
| 87 | struct file *filp = iocb->ki_filp; |
| 88 | struct qrtr_tun *tun = filp->private_data; |
| 89 | size_t len = iov_iter_count(from); |
| 90 | ssize_t ret; |
| 91 | void *kbuf; |
| 92 | |
Sabyrzhan Tasbolatov | 2a80c15 | 2021-02-02 15:20:59 +0600 | [diff] [blame] | 93 | if (!len) |
| 94 | return -EINVAL; |
| 95 | |
| 96 | if (len > KMALLOC_MAX_SIZE) |
| 97 | return -ENOMEM; |
| 98 | |
Bjorn Andersson | 28fb4e5 | 2018-04-26 22:28:49 -0700 | [diff] [blame] | 99 | kbuf = kzalloc(len, GFP_KERNEL); |
| 100 | if (!kbuf) |
| 101 | return -ENOMEM; |
| 102 | |
Navid Emamdoost | a21b7f0 | 2019-09-11 10:09:02 -0500 | [diff] [blame] | 103 | if (!copy_from_iter_full(kbuf, len, from)) { |
| 104 | kfree(kbuf); |
Bjorn Andersson | 28fb4e5 | 2018-04-26 22:28:49 -0700 | [diff] [blame] | 105 | return -EFAULT; |
Navid Emamdoost | a21b7f0 | 2019-09-11 10:09:02 -0500 | [diff] [blame] | 106 | } |
Bjorn Andersson | 28fb4e5 | 2018-04-26 22:28:49 -0700 | [diff] [blame] | 107 | |
| 108 | ret = qrtr_endpoint_post(&tun->ep, kbuf, len); |
| 109 | |
Navid Emamdoost | a21b7f0 | 2019-09-11 10:09:02 -0500 | [diff] [blame] | 110 | kfree(kbuf); |
Bjorn Andersson | 28fb4e5 | 2018-04-26 22:28:49 -0700 | [diff] [blame] | 111 | return ret < 0 ? ret : len; |
| 112 | } |
| 113 | |
| 114 | static __poll_t qrtr_tun_poll(struct file *filp, poll_table *wait) |
| 115 | { |
| 116 | struct qrtr_tun *tun = filp->private_data; |
| 117 | __poll_t mask = 0; |
| 118 | |
| 119 | poll_wait(filp, &tun->readq, wait); |
| 120 | |
| 121 | if (!skb_queue_empty(&tun->queue)) |
| 122 | mask |= EPOLLIN | EPOLLRDNORM; |
| 123 | |
| 124 | return mask; |
| 125 | } |
| 126 | |
| 127 | static int qrtr_tun_release(struct inode *inode, struct file *filp) |
| 128 | { |
| 129 | struct qrtr_tun *tun = filp->private_data; |
Bjorn Andersson | 28fb4e5 | 2018-04-26 22:28:49 -0700 | [diff] [blame] | 130 | |
| 131 | qrtr_endpoint_unregister(&tun->ep); |
| 132 | |
| 133 | /* Discard all SKBs */ |
Christophe JAILLET | 21d8bd1 | 2019-10-30 07:36:40 +0100 | [diff] [blame] | 134 | skb_queue_purge(&tun->queue); |
Bjorn Andersson | 28fb4e5 | 2018-04-26 22:28:49 -0700 | [diff] [blame] | 135 | |
| 136 | kfree(tun); |
| 137 | |
| 138 | return 0; |
| 139 | } |
| 140 | |
| 141 | static const struct file_operations qrtr_tun_ops = { |
| 142 | .owner = THIS_MODULE, |
| 143 | .open = qrtr_tun_open, |
| 144 | .poll = qrtr_tun_poll, |
| 145 | .read_iter = qrtr_tun_read_iter, |
| 146 | .write_iter = qrtr_tun_write_iter, |
| 147 | .release = qrtr_tun_release, |
| 148 | }; |
| 149 | |
| 150 | static struct miscdevice qrtr_tun_miscdev = { |
| 151 | MISC_DYNAMIC_MINOR, |
| 152 | "qrtr-tun", |
| 153 | &qrtr_tun_ops, |
| 154 | }; |
| 155 | |
| 156 | static int __init qrtr_tun_init(void) |
| 157 | { |
| 158 | int ret; |
| 159 | |
| 160 | ret = misc_register(&qrtr_tun_miscdev); |
| 161 | if (ret) |
| 162 | pr_err("failed to register Qualcomm IPC Router tun device\n"); |
| 163 | |
| 164 | return ret; |
| 165 | } |
| 166 | |
| 167 | static void __exit qrtr_tun_exit(void) |
| 168 | { |
| 169 | misc_deregister(&qrtr_tun_miscdev); |
| 170 | } |
| 171 | |
| 172 | module_init(qrtr_tun_init); |
| 173 | module_exit(qrtr_tun_exit); |
| 174 | |
| 175 | MODULE_DESCRIPTION("Qualcomm IPC Router TUN device"); |
| 176 | MODULE_LICENSE("GPL v2"); |