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/*
* TUN - Universal TUN/TAP device driver.
* Copyright (C) 1999-2000 Maxim Krasnyansky <max_mk@yahoo.com>
*
* This program 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 program 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.
*
* $Id: tun.c,v 1.12 2001/03/08 03:29:27 maxk Exp $
*/
/*
* Daniel Podlejski <underley@underley.eu.org>
* Modifications for 2.3.99-pre5 kernel.
*/
#define TUN_VER "1.4"
#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/random.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/miscdevice.h>
#include <linux/rtnetlink.h>
#include <linux/if.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#ifdef TUN_DEBUG
static int debug;
#endif
/* Network device part of the driver */
/* Net device open. */
static int tun_net_open(struct net_device *dev)
{
netif_start_queue(dev);
return 0;
}
/* Net device close. */
static int tun_net_close(struct net_device *dev)
{
netif_stop_queue(dev);
return 0;
}
/* Net device start xmit */
static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct tun_struct *tun = (struct tun_struct *)dev->priv;
DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->name, skb->len);
/* Drop packet if interface is not attached */
if (!tun->attached)
goto drop;
/* Queue packet */
if (!(tun->flags & TUN_ONE_QUEUE)) {
/* Normal queueing mode.
* Packet scheduler handles dropping. */
if (skb_queue_len(&tun->readq) >= TUN_READQ_SIZE)
netif_stop_queue(dev);
} else {
/* Single queue mode.
* Driver handles dropping itself. */
if (skb_queue_len(&tun->readq) >= dev->tx_queue_len)
goto drop;
}
skb_queue_tail(&tun->readq, skb);
/* Notify and wake up reader process */
if (tun->flags & TUN_FASYNC)
kill_fasync(&tun->fasync, SIGIO, POLL_IN);
wake_up_interruptible(&tun->read_wait);
return 0;
drop:
tun->stats.tx_dropped++;
kfree_skb(skb);
return 0;
}
static void tun_net_mclist(struct net_device *dev)
{
/* Nothing to do for multicast filters.
* We always accept all frames. */
return;
}
static struct net_device_stats *tun_net_stats(struct net_device *dev)
{
struct tun_struct *tun = (struct tun_struct *)dev->priv;
return &tun->stats;
}
/* Initialize net device. */
int tun_net_init(struct net_device *dev)
{
struct tun_struct *tun = (struct tun_struct *)dev->priv;
DBG(KERN_INFO "%s: tun_net_init\n", tun->name);
SET_MODULE_OWNER(dev);
dev->open = tun_net_open;
dev->hard_start_xmit = tun_net_xmit;
dev->stop = tun_net_close;
dev->get_stats = tun_net_stats;
switch (tun->flags & TUN_TYPE_MASK) {
case TUN_TUN_DEV:
/* Point-to-Point TUN Device */
dev->hard_header_len = 0;
dev->addr_len = 0;
dev->mtu = 1500;
/* Type PPP seems most suitable */
dev->type = ARPHRD_PPP;
dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
dev->tx_queue_len = 10;
break;
case TUN_TAP_DEV:
/* Ethernet TAP Device */
dev->set_multicast_list = tun_net_mclist;
/* Generate random Ethernet address. */
*(u16 *)dev->dev_addr = htons(0x00FF);
get_random_bytes(dev->dev_addr + sizeof(u16), 4);
ether_setup(dev);
break;
};
return 0;
}
/* Character device part */
/* Poll */
static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
{
struct tun_struct *tun = (struct tun_struct *)file->private_data;
unsigned int mask = POLLOUT | POLLWRNORM;
if (!tun)
return -EBADFD;
DBG(KERN_INFO "%s: tun_chr_poll\n", tun->name);
poll_wait(file, &tun->read_wait, wait);
if (skb_queue_len(&tun->readq))
mask |= POLLIN | POLLRDNORM;
return mask;
}
/* Get packet from user space buffer(already verified) */
static __inline__ ssize_t tun_get_user(struct tun_struct *tun, const char *buf, size_t count)
{
struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
register const char *ptr = buf;
register int len = count;
struct sk_buff *skb;
if (!(tun->flags & TUN_NO_PI)) {
if ((len -= sizeof(pi)) < 0)
return -EINVAL;
copy_from_user(&pi, ptr, sizeof(pi));
ptr += sizeof(pi);
}
if (!(skb = alloc_skb(len + 2, GFP_KERNEL))) {
tun->stats.rx_dropped++;
return -ENOMEM;
}
skb_reserve(skb, 2);
copy_from_user(skb_put(skb, len), ptr, len);
skb->dev = &tun->dev;
switch (tun->flags & TUN_TYPE_MASK) {
case TUN_TUN_DEV:
skb->mac.raw = skb->data;
skb->protocol = pi.proto;
break;
case TUN_TAP_DEV:
skb->protocol = eth_type_trans(skb, &tun->dev);
break;
};
if (tun->flags & TUN_NOCHECKSUM)
skb->ip_summed = CHECKSUM_UNNECESSARY;
netif_rx_ni(skb);
tun->stats.rx_packets++;
tun->stats.rx_bytes += len;
return count;
}
/* Write */
static ssize_t tun_chr_write(struct file * file, const char * buf,
size_t count, loff_t *pos)
{
struct tun_struct *tun = (struct tun_struct *)file->private_data;
if (!tun)
return -EBADFD;
DBG(KERN_INFO "%s: tun_chr_write %d\n", tun->name, count);
if (verify_area(VERIFY_READ, buf, count))
return -EFAULT;
return tun_get_user(tun, buf, count);
}
/* Put packet to user space buffer(already verified) */
static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
struct sk_buff *skb,
char *buf, int count)
{
struct tun_pi pi = { 0, skb->protocol };
int len = count, total = 0;
char *ptr = buf;
if (!(tun->flags & TUN_NO_PI)) {
if ((len -= sizeof(pi)) < 0)
return -EINVAL;
if (len < skb->len) {
/* Packet will be striped */
pi.flags |= TUN_PKT_STRIP;
}
copy_to_user(ptr, &pi, sizeof(pi));
total += sizeof(pi);
ptr += sizeof(pi);
}
len = MIN(skb->len, len);
copy_to_user(ptr, skb->data, len);
total += len;
tun->stats.tx_packets++;
tun->stats.tx_bytes += len;
return total;
}
/* Read */
static ssize_t tun_chr_read(struct file * file, char * buf,
size_t count, loff_t *pos)
{
struct tun_struct *tun = (struct tun_struct *)file->private_data;
DECLARE_WAITQUEUE(wait, current);
struct sk_buff *skb;
ssize_t ret = 0;
if (!tun)
return -EBADFD;
DBG(KERN_INFO "%s: tun_chr_read\n", tun->name);
add_wait_queue(&tun->read_wait, &wait);
while (count) {
current->state = TASK_INTERRUPTIBLE;
/* Read frames from the queue */
if (!(skb=skb_dequeue(&tun->readq))) {
if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
/* Nothing to read, let's sleep */
schedule();
continue;
}
netif_start_queue(&tun->dev);
if (!verify_area(VERIFY_WRITE, buf, count))
ret = tun_put_user(tun, skb, buf, count);
else
ret = -EFAULT;
kfree_skb(skb);
break;
}
current->state = TASK_RUNNING;
remove_wait_queue(&tun->read_wait, &wait);
return ret;
}
static int tun_set_iff(struct file *file, struct ifreq *ifr)
{
struct tun_struct *tun;
struct net_device *dev;
int err;
dev = __dev_get_by_name(ifr->ifr_name);
if (dev) {
/* Device exist */
tun = dev->priv;
if (dev->init != tun_net_init || tun->attached)
return -EBUSY;
/* Check permissions */
if (tun->owner != -1)
if (current->euid != tun->owner && !capable(CAP_NET_ADMIN))
return -EPERM;
} else {
char *name;
/* Allocate new device */
if (!(tun = kmalloc(sizeof(struct tun_struct), GFP_KERNEL)) )
return -ENOMEM;
memset(tun, 0, sizeof(struct tun_struct));
skb_queue_head_init(&tun->readq);
init_waitqueue_head(&tun->read_wait);
tun->owner = -1;
tun->dev.init = tun_net_init;
tun->dev.priv = tun;
err = -EINVAL;
/* Set dev type */
if (ifr->ifr_flags & IFF_TUN) {
/* TUN device */
tun->flags |= TUN_TUN_DEV;
name = "tun%d";
} else if (ifr->ifr_flags & IFF_TAP) {
/* TAP device */
tun->flags |= TUN_TAP_DEV;
name = "tap%d";
} else
goto failed;
if (*ifr->ifr_name)
name = ifr->ifr_name;
if ((err = dev_alloc_name(&tun->dev, name)) < 0)
goto failed;
if ((err = register_netdevice(&tun->dev)))
goto failed;
MOD_INC_USE_COUNT;
tun->name = tun->dev.name;
}
DBG(KERN_INFO "%s: tun_set_iff\n", tun->name);
if (ifr->ifr_flags & IFF_NO_PI)
tun->flags |= TUN_NO_PI;
if (ifr->ifr_flags & IFF_ONE_QUEUE)
tun->flags |= TUN_ONE_QUEUE;
file->private_data = tun;
tun->attached = 1;
strcpy(ifr->ifr_name, tun->name);
return 0;
failed:
kfree(tun);
return err;
}
static int tun_chr_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct tun_struct *tun = (struct tun_struct *)file->private_data;
if (cmd == TUNSETIFF && !tun) {
struct ifreq ifr;
int err;
if (copy_from_user(&ifr, (void *)arg, sizeof(ifr)))
return -EFAULT;
ifr.ifr_name[IFNAMSIZ-1] = '\0';
rtnl_lock();
err = tun_set_iff(file, &ifr);
rtnl_unlock();
if (err)
return err;
copy_to_user((void *)arg, &ifr, sizeof(ifr));
return 0;
}
if (!tun)
return -EBADFD;
DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->name, cmd);
switch (cmd) {
case TUNSETNOCSUM:
/* Disable/Enable checksum */
if (arg)
tun->flags |= TUN_NOCHECKSUM;
else
tun->flags &= ~TUN_NOCHECKSUM;
DBG(KERN_INFO "%s: checksum %s\n",
tun->name, arg ? "disabled" : "enabled");
break;
case TUNSETPERSIST:
/* Disable/Enable persist mode */
if (arg)
tun->flags |= TUN_PERSIST;
else
tun->flags &= ~TUN_PERSIST;
DBG(KERN_INFO "%s: persist %s\n",
tun->name, arg ? "disabled" : "enabled");
break;
case TUNSETOWNER:
/* Set owner of the device */
tun->owner = (uid_t) arg;
DBG(KERN_INFO "%s: owner set to %d\n", tun->owner);
break;
#ifdef TUN_DEBUG
case TUNSETDEBUG:
tun->debug = arg;
break;
#endif
default:
return -EINVAL;
};
return 0;
}
static int tun_chr_fasync(int fd, struct file *file, int on)
{
struct tun_struct *tun = (struct tun_struct *)file->private_data;
int ret;
if (!tun)
return -EBADFD;
DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->name, on);
if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
return ret;
if (on) {
tun->flags |= TUN_FASYNC;
if (!file->f_owner.pid) {
file->f_owner.pid = current->pid;
file->f_owner.uid = current->uid;
file->f_owner.euid = current->euid;
}
} else
tun->flags &= ~TUN_FASYNC;
return 0;
}
static int tun_chr_open(struct inode *inode, struct file * file)
{
DBG1(KERN_INFO "tunX: tun_chr_open\n");
file->private_data = NULL;
return 0;
}
static int tun_chr_close(struct inode *inode, struct file *file)
{
struct tun_struct *tun = (struct tun_struct *)file->private_data;
if (!tun)
return 0;
DBG(KERN_INFO "%s: tun_chr_close\n", tun->name);
tun_chr_fasync(-1, file, 0);
rtnl_lock();
/* Detach from net device */
file->private_data = NULL;
tun->attached = 0;
/* Drop read queue */
skb_queue_purge(&tun->readq);
if (!(tun->flags & TUN_PERSIST)) {
dev_close(&tun->dev);
unregister_netdevice(&tun->dev);
kfree(tun);
MOD_DEC_USE_COUNT;
}
rtnl_unlock();
return 0;
}
static struct file_operations tun_fops = {
owner: THIS_MODULE,
llseek: no_llseek,
read: tun_chr_read,
write: tun_chr_write,
poll: tun_chr_poll,
ioctl: tun_chr_ioctl,
open: tun_chr_open,
release:tun_chr_close,
fasync: tun_chr_fasync
};
static struct miscdevice tun_miscdev=
{
TUN_MINOR,
"net/tun",
&tun_fops
};
int __init tun_init(void)
{
printk(KERN_INFO "Universal TUN/TAP device driver %s "
"(C)1999-2001 Maxim Krasnyansky\n", TUN_VER);
if (misc_register(&tun_miscdev)) {
printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
return -EIO;
}
return 0;
}
void tun_cleanup(void)
{
misc_deregister(&tun_miscdev);
}
module_init(tun_init);
module_exit(tun_cleanup);
MODULE_LICENSE("GPL");
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