tun.c 42.0 KB
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/*
 *  TUN - Universal TUN/TAP device driver.
 *  Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.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 1.15 2002/03/01 02:44:24 maxk Exp $
 */

/*
 *  Changes:
 *
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 *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
 *    Add TUNSETLINK ioctl to set the link encapsulation
 *
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 *  Mark Smith <markzzzsmith@yahoo.com.au>
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 *    Use eth_random_addr() for tap MAC address.
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 *
 *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
 *    Fixes in packet dropping, queue length setting and queue wakeup.
 *    Increased default tx queue length.
 *    Added ethtool API.
 *    Minor cleanups
 *
 *  Daniel Podlejski <underley@underley.eu.org>
 *    Modifications for 2.3.99-pre5 kernel.
 */

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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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#define DRV_NAME	"tun"
#define DRV_VERSION	"1.6"
#define DRV_DESCRIPTION	"Universal TUN/TAP device driver"
#define DRV_COPYRIGHT	"(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/miscdevice.h>
#include <linux/ethtool.h>
#include <linux/rtnetlink.h>
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#include <linux/compat.h>
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#include <linux/if.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#include <linux/crc32.h>
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#include <linux/nsproxy.h>
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#include <linux/virtio_net.h>
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#include <linux/rcupdate.h>
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#include <net/net_namespace.h>
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#include <net/netns/generic.h>
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#include <net/rtnetlink.h>
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#include <net/sock.h>
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#include <asm/uaccess.h>

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/* Uncomment to enable debugging */
/* #define TUN_DEBUG 1 */

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#ifdef TUN_DEBUG
static int debug;
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#define tun_debug(level, tun, fmt, args...)			\
do {								\
	if (tun->debug)						\
		netdev_printk(level, tun->dev, fmt, ##args);	\
} while (0)
#define DBG1(level, fmt, args...)				\
do {								\
	if (debug == 2)						\
		printk(level fmt, ##args);			\
} while (0)
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#else
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#define tun_debug(level, tun, fmt, args...)			\
do {								\
	if (0)							\
		netdev_printk(level, tun->dev, fmt, ##args);	\
} while (0)
#define DBG1(level, fmt, args...)				\
do {								\
	if (0)							\
		printk(level fmt, ##args);			\
} while (0)
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#endif

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#define GOODCOPY_LEN 128

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#define FLT_EXACT_COUNT 8
struct tap_filter {
	unsigned int    count;    /* Number of addrs. Zero means disabled */
	u32             mask[2];  /* Mask of the hashed addrs */
	unsigned char	addr[FLT_EXACT_COUNT][ETH_ALEN];
};

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struct tun_file {
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	atomic_t count;
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	struct tun_struct *tun;
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	struct net *net;
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};

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struct tun_sock;

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struct tun_struct {
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	struct tun_file		*tfile;
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	unsigned int 		flags;
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	kuid_t			owner;
	kgid_t			group;
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	struct net_device	*dev;
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	netdev_features_t	set_features;
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#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
			  NETIF_F_TSO6|NETIF_F_UFO)
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	struct fasync_struct	*fasync;
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	struct tap_filter       txflt;
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	struct socket		socket;
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	struct socket_wq	wq;
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	int			vnet_hdr_sz;

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#ifdef TUN_DEBUG
	int debug;
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#endif
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};
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struct tun_sock {
	struct sock		sk;
	struct tun_struct	*tun;
};

static inline struct tun_sock *tun_sk(struct sock *sk)
{
	return container_of(sk, struct tun_sock, sk);
}

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static int tun_attach(struct tun_struct *tun, struct file *file)
{
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	struct tun_file *tfile = file->private_data;
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	int err;
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	ASSERT_RTNL();

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	netif_tx_lock_bh(tun->dev);

	err = -EINVAL;
	if (tfile->tun)
		goto out;

	err = -EBUSY;
	if (tun->tfile)
		goto out;

	err = 0;
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	tfile->tun = tun;
	tun->tfile = tfile;
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	tun->socket.file = file;
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	netif_carrier_on(tun->dev);
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	dev_hold(tun->dev);
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	sock_hold(tun->socket.sk);
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	atomic_inc(&tfile->count);
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out:
	netif_tx_unlock_bh(tun->dev);
	return err;
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}

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static void __tun_detach(struct tun_struct *tun)
{
	/* Detach from net device */
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	netif_tx_lock_bh(tun->dev);
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	netif_carrier_off(tun->dev);
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	tun->tfile = NULL;
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	netif_tx_unlock_bh(tun->dev);
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	/* Drop read queue */
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	skb_queue_purge(&tun->socket.sk->sk_receive_queue);
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	/* Drop the extra count on the net device */
	dev_put(tun->dev);
}

static void tun_detach(struct tun_struct *tun)
{
	rtnl_lock();
	__tun_detach(tun);
	rtnl_unlock();
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}

static struct tun_struct *__tun_get(struct tun_file *tfile)
{
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	struct tun_struct *tun = NULL;

	if (atomic_inc_not_zero(&tfile->count))
		tun = tfile->tun;

	return tun;
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}

static struct tun_struct *tun_get(struct file *file)
{
	return __tun_get(file->private_data);
}

static void tun_put(struct tun_struct *tun)
{
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	struct tun_file *tfile = tun->tfile;

	if (atomic_dec_and_test(&tfile->count))
		tun_detach(tfile->tun);
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}

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/* TAP filtering */
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static void addr_hash_set(u32 *mask, const u8 *addr)
{
	int n = ether_crc(ETH_ALEN, addr) >> 26;
	mask[n >> 5] |= (1 << (n & 31));
}

static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
{
	int n = ether_crc(ETH_ALEN, addr) >> 26;
	return mask[n >> 5] & (1 << (n & 31));
}

static int update_filter(struct tap_filter *filter, void __user *arg)
{
	struct { u8 u[ETH_ALEN]; } *addr;
	struct tun_filter uf;
	int err, alen, n, nexact;

	if (copy_from_user(&uf, arg, sizeof(uf)))
		return -EFAULT;

	if (!uf.count) {
		/* Disabled */
		filter->count = 0;
		return 0;
	}

	alen = ETH_ALEN * uf.count;
	addr = kmalloc(alen, GFP_KERNEL);
	if (!addr)
		return -ENOMEM;

	if (copy_from_user(addr, arg + sizeof(uf), alen)) {
		err = -EFAULT;
		goto done;
	}

	/* The filter is updated without holding any locks. Which is
	 * perfectly safe. We disable it first and in the worst
	 * case we'll accept a few undesired packets. */
	filter->count = 0;
	wmb();

	/* Use first set of addresses as an exact filter */
	for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
		memcpy(filter->addr[n], addr[n].u, ETH_ALEN);

	nexact = n;

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	/* Remaining multicast addresses are hashed,
	 * unicast will leave the filter disabled. */
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	memset(filter->mask, 0, sizeof(filter->mask));
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	for (; n < uf.count; n++) {
		if (!is_multicast_ether_addr(addr[n].u)) {
			err = 0; /* no filter */
			goto done;
		}
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		addr_hash_set(filter->mask, addr[n].u);
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	}
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	/* For ALLMULTI just set the mask to all ones.
	 * This overrides the mask populated above. */
	if ((uf.flags & TUN_FLT_ALLMULTI))
		memset(filter->mask, ~0, sizeof(filter->mask));

	/* Now enable the filter */
	wmb();
	filter->count = nexact;

	/* Return the number of exact filters */
	err = nexact;

done:
	kfree(addr);
	return err;
}

/* Returns: 0 - drop, !=0 - accept */
static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
{
	/* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
	 * at this point. */
	struct ethhdr *eh = (struct ethhdr *) skb->data;
	int i;

	/* Exact match */
	for (i = 0; i < filter->count; i++)
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		if (ether_addr_equal(eh->h_dest, filter->addr[i]))
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			return 1;

	/* Inexact match (multicast only) */
	if (is_multicast_ether_addr(eh->h_dest))
		return addr_hash_test(filter->mask, eh->h_dest);

	return 0;
}

/*
 * Checks whether the packet is accepted or not.
 * Returns: 0 - drop, !=0 - accept
 */
static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
{
	if (!filter->count)
		return 1;

	return run_filter(filter, skb);
}

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/* Network device part of the driver */

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static const struct ethtool_ops tun_ethtool_ops;
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/* Net device detach from fd. */
static void tun_net_uninit(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);
	struct tun_file *tfile = tun->tfile;

	/* Inform the methods they need to stop using the dev.
	 */
	if (tfile) {
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		wake_up_all(&tun->wq.wait);
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		if (atomic_dec_and_test(&tfile->count))
			__tun_detach(tun);
	}
}

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static void tun_free_netdev(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);

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	BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags));

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	sk_release_kernel(tun->socket.sk);
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}

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/* 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 */
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static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
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{
	struct tun_struct *tun = netdev_priv(dev);

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	tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
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	/* Drop packet if interface is not attached */
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	if (!tun->tfile)
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		goto drop;

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	/* Drop if the filter does not like it.
	 * This is a noop if the filter is disabled.
	 * Filter can be enabled only for the TAP devices. */
	if (!check_filter(&tun->txflt, skb))
		goto drop;

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	if (tun->socket.sk->sk_filter &&
	    sk_filter(tun->socket.sk, skb))
		goto drop;

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	if (skb_queue_len(&tun->socket.sk->sk_receive_queue) >= dev->tx_queue_len) {
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		if (!(tun->flags & TUN_ONE_QUEUE)) {
			/* Normal queueing mode. */
			/* Packet scheduler handles dropping of further packets. */
			netif_stop_queue(dev);

			/* We won't see all dropped packets individually, so overrun
			 * error is more appropriate. */
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			dev->stats.tx_fifo_errors++;
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		} else {
			/* Single queue mode.
			 * Driver handles dropping of all packets itself. */
			goto drop;
		}
	}

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	/* Orphan the skb - required as we might hang on to it
	 * for indefinite time. */
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	if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
		goto drop;
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	skb_orphan(skb);

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	/* Enqueue packet */
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	skb_queue_tail(&tun->socket.sk->sk_receive_queue, skb);
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	/* Notify and wake up reader process */
	if (tun->flags & TUN_FASYNC)
		kill_fasync(&tun->fasync, SIGIO, POLL_IN);
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	wake_up_interruptible_poll(&tun->wq.wait, POLLIN |
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				   POLLRDNORM | POLLRDBAND);
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	return NETDEV_TX_OK;
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drop:
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	dev->stats.tx_dropped++;
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	kfree_skb(skb);
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	return NETDEV_TX_OK;
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}

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static void tun_net_mclist(struct net_device *dev)
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{
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	/*
	 * This callback is supposed to deal with mc filter in
	 * _rx_ path and has nothing to do with the _tx_ path.
	 * In rx path we always accept everything userspace gives us.
	 */
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}

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#define MIN_MTU 68
#define MAX_MTU 65535

static int
tun_net_change_mtu(struct net_device *dev, int new_mtu)
{
	if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
		return -EINVAL;
	dev->mtu = new_mtu;
	return 0;
}

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static netdev_features_t tun_net_fix_features(struct net_device *dev,
	netdev_features_t features)
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{
	struct tun_struct *tun = netdev_priv(dev);

	return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
}
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#ifdef CONFIG_NET_POLL_CONTROLLER
static void tun_poll_controller(struct net_device *dev)
{
	/*
	 * Tun only receives frames when:
	 * 1) the char device endpoint gets data from user space
	 * 2) the tun socket gets a sendmsg call from user space
	 * Since both of those are syncronous operations, we are guaranteed
	 * never to have pending data when we poll for it
	 * so theres nothing to do here but return.
	 * We need this though so netpoll recognizes us as an interface that
	 * supports polling, which enables bridge devices in virt setups to
	 * still use netconsole
	 */
	return;
}
#endif
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static const struct net_device_ops tun_netdev_ops = {
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	.ndo_uninit		= tun_net_uninit,
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	.ndo_open		= tun_net_open,
	.ndo_stop		= tun_net_close,
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	.ndo_start_xmit		= tun_net_xmit,
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	.ndo_change_mtu		= tun_net_change_mtu,
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	.ndo_fix_features	= tun_net_fix_features,
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#ifdef CONFIG_NET_POLL_CONTROLLER
	.ndo_poll_controller	= tun_poll_controller,
#endif
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};

static const struct net_device_ops tap_netdev_ops = {
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	.ndo_uninit		= tun_net_uninit,
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	.ndo_open		= tun_net_open,
	.ndo_stop		= tun_net_close,
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	.ndo_start_xmit		= tun_net_xmit,
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	.ndo_change_mtu		= tun_net_change_mtu,
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	.ndo_fix_features	= tun_net_fix_features,
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	.ndo_set_rx_mode	= tun_net_mclist,
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	.ndo_set_mac_address	= eth_mac_addr,
	.ndo_validate_addr	= eth_validate_addr,
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#ifdef CONFIG_NET_POLL_CONTROLLER
	.ndo_poll_controller	= tun_poll_controller,
#endif
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};

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/* Initialize net device. */
static void tun_net_init(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);
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	switch (tun->flags & TUN_TYPE_MASK) {
	case TUN_TUN_DEV:
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		dev->netdev_ops = &tun_netdev_ops;

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		/* Point-to-Point TUN Device */
		dev->hard_header_len = 0;
		dev->addr_len = 0;
		dev->mtu = 1500;

		/* Zero header length */
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		dev->type = ARPHRD_NONE;
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		dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
		dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
		break;

	case TUN_TAP_DEV:
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		dev->netdev_ops = &tap_netdev_ops;
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		/* Ethernet TAP Device */
		ether_setup(dev);
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		dev->priv_flags &= ~IFF_TX_SKB_SHARING;
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		eth_hw_addr_random(dev);
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		dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
		break;
	}
}

/* Character device part */

/* Poll */
static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
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{
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	struct tun_file *tfile = file->private_data;
	struct tun_struct *tun = __tun_get(tfile);
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	struct sock *sk;
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	unsigned int mask = 0;
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	if (!tun)
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		return POLLERR;
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	sk = tun->socket.sk;
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	tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
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	poll_wait(file, &tun->wq.wait, wait);
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	if (!skb_queue_empty(&sk->sk_receive_queue))
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		mask |= POLLIN | POLLRDNORM;

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	if (sock_writeable(sk) ||
	    (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
	     sock_writeable(sk)))
		mask |= POLLOUT | POLLWRNORM;

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	if (tun->dev->reg_state != NETREG_REGISTERED)
		mask = POLLERR;

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	tun_put(tun);
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	return mask;
}

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/* prepad is the amount to reserve at front.  len is length after that.
 * linear is a hint as to how much to copy (usually headers). */
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static struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
				     size_t prepad, size_t len,
				     size_t linear, int noblock)
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{
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	struct sock *sk = tun->socket.sk;
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	struct sk_buff *skb;
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	int err;
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	/* Under a page?  Don't bother with paged skb. */
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	if (prepad + len < PAGE_SIZE || !linear)
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		linear = len;
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	skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
				   &err);
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	if (!skb)
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		return ERR_PTR(err);
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	skb_reserve(skb, prepad);
	skb_put(skb, linear);
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	skb->data_len = len - linear;
	skb->len += len - linear;
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	return skb;
}

606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683
/* set skb frags from iovec, this can move to core network code for reuse */
static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
				  int offset, size_t count)
{
	int len = iov_length(from, count) - offset;
	int copy = skb_headlen(skb);
	int size, offset1 = 0;
	int i = 0;

	/* Skip over from offset */
	while (count && (offset >= from->iov_len)) {
		offset -= from->iov_len;
		++from;
		--count;
	}

	/* copy up to skb headlen */
	while (count && (copy > 0)) {
		size = min_t(unsigned int, copy, from->iov_len - offset);
		if (copy_from_user(skb->data + offset1, from->iov_base + offset,
				   size))
			return -EFAULT;
		if (copy > size) {
			++from;
			--count;
			offset = 0;
		} else
			offset += size;
		copy -= size;
		offset1 += size;
	}

	if (len == offset1)
		return 0;

	while (count--) {
		struct page *page[MAX_SKB_FRAGS];
		int num_pages;
		unsigned long base;
		unsigned long truesize;

		len = from->iov_len - offset;
		if (!len) {
			offset = 0;
			++from;
			continue;
		}
		base = (unsigned long)from->iov_base + offset;
		size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
		if (i + size > MAX_SKB_FRAGS)
			return -EMSGSIZE;
		num_pages = get_user_pages_fast(base, size, 0, &page[i]);
		if (num_pages != size) {
			for (i = 0; i < num_pages; i++)
				put_page(page[i]);
			return -EFAULT;
		}
		truesize = size * PAGE_SIZE;
		skb->data_len += len;
		skb->len += len;
		skb->truesize += truesize;
		atomic_add(truesize, &skb->sk->sk_wmem_alloc);
		while (len) {
			int off = base & ~PAGE_MASK;
			int size = min_t(int, len, PAGE_SIZE - off);
			__skb_fill_page_desc(skb, i, page[i], off, size);
			skb_shinfo(skb)->nr_frags++;
			/* increase sk_wmem_alloc */
			base += size;
			len -= size;
			i++;
		}
		offset = 0;
		++from;
	}
	return 0;
}

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Linus Torvalds 已提交
684
/* Get packet from user space buffer */
685 686 687
static ssize_t tun_get_user(struct tun_struct *tun, void *msg_control,
			    const struct iovec *iv, size_t total_len,
			    size_t count, int noblock)
L
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688
{
689
	struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
L
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690
	struct sk_buff *skb;
691
	size_t len = total_len, align = NET_SKB_PAD;
692
	struct virtio_net_hdr gso = { 0 };
693
	int offset = 0;
694 695 696
	int copylen;
	bool zerocopy = false;
	int err;
L
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697 698

	if (!(tun->flags & TUN_NO_PI)) {
699
		if ((len -= sizeof(pi)) > total_len)
L
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700 701
			return -EINVAL;

702
		if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
L
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703
			return -EFAULT;
704
		offset += sizeof(pi);
L
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	}

707
	if (tun->flags & TUN_VNET_HDR) {
708
		if ((len -= tun->vnet_hdr_sz) > total_len)
709 710
			return -EINVAL;

711
		if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
712 713
			return -EFAULT;

714 715 716 717
		if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
		    gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
			gso.hdr_len = gso.csum_start + gso.csum_offset + 2;

718 719
		if (gso.hdr_len > len)
			return -EINVAL;
720
		offset += tun->vnet_hdr_sz;
721 722
	}

723
	if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
724
		align += NET_IP_ALIGN;
H
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725 726
		if (unlikely(len < ETH_HLEN ||
			     (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
727 728
			return -EINVAL;
	}
729

730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757
	if (msg_control)
		zerocopy = true;

	if (zerocopy) {
		/* Userspace may produce vectors with count greater than
		 * MAX_SKB_FRAGS, so we need to linearize parts of the skb
		 * to let the rest of data to be fit in the frags.
		 */
		if (count > MAX_SKB_FRAGS) {
			copylen = iov_length(iv, count - MAX_SKB_FRAGS);
			if (copylen < offset)
				copylen = 0;
			else
				copylen -= offset;
		} else
				copylen = 0;
		/* There are 256 bytes to be copied in skb, so there is enough
		 * room for skb expand head in case it is used.
		 * The rest of the buffer is mapped from userspace.
		 */
		if (copylen < gso.hdr_len)
			copylen = gso.hdr_len;
		if (!copylen)
			copylen = GOODCOPY_LEN;
	} else
		copylen = len;

	skb = tun_alloc_skb(tun, align, copylen, gso.hdr_len, noblock);
758 759 760 761
	if (IS_ERR(skb)) {
		if (PTR_ERR(skb) != -EAGAIN)
			tun->dev->stats.rx_dropped++;
		return PTR_ERR(skb);
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	}

764 765 766 767 768 769
	if (zerocopy)
		err = zerocopy_sg_from_iovec(skb, iv, offset, count);
	else
		err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);

	if (err) {
770
		tun->dev->stats.rx_dropped++;
D
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771
		kfree_skb(skb);
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		return -EFAULT;
D
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773
	}
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775 776 777 778 779 780 781
	if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
		if (!skb_partial_csum_set(skb, gso.csum_start,
					  gso.csum_offset)) {
			tun->dev->stats.rx_frame_errors++;
			kfree_skb(skb);
			return -EINVAL;
		}
782
	}
783

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	switch (tun->flags & TUN_TYPE_MASK) {
	case TUN_TUN_DEV:
786 787 788 789 790 791 792 793 794 795 796 797 798 799 800
		if (tun->flags & TUN_NO_PI) {
			switch (skb->data[0] & 0xf0) {
			case 0x40:
				pi.proto = htons(ETH_P_IP);
				break;
			case 0x60:
				pi.proto = htons(ETH_P_IPV6);
				break;
			default:
				tun->dev->stats.rx_dropped++;
				kfree_skb(skb);
				return -EINVAL;
			}
		}

801
		skb_reset_mac_header(skb);
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802
		skb->protocol = pi.proto;
803
		skb->dev = tun->dev;
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		break;
	case TUN_TAP_DEV:
		skb->protocol = eth_type_trans(skb, tun->dev);
		break;
808
	}
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Linus Torvalds 已提交
809

810 811 812 813 814 815 816 817 818
	if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
		pr_debug("GSO!\n");
		switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
		case VIRTIO_NET_HDR_GSO_TCPV4:
			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
			break;
		case VIRTIO_NET_HDR_GSO_TCPV6:
			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
			break;
819 820 821
		case VIRTIO_NET_HDR_GSO_UDP:
			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
			break;
822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841
		default:
			tun->dev->stats.rx_frame_errors++;
			kfree_skb(skb);
			return -EINVAL;
		}

		if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;

		skb_shinfo(skb)->gso_size = gso.gso_size;
		if (skb_shinfo(skb)->gso_size == 0) {
			tun->dev->stats.rx_frame_errors++;
			kfree_skb(skb);
			return -EINVAL;
		}

		/* Header must be checked, and gso_segs computed. */
		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
		skb_shinfo(skb)->gso_segs = 0;
	}
842

843 844 845 846 847 848
	/* copy skb_ubuf_info for callback when skb has no error */
	if (zerocopy) {
		skb_shinfo(skb)->destructor_arg = msg_control;
		skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
	}

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849
	netif_rx_ni(skb);
850

851 852
	tun->dev->stats.rx_packets++;
	tun->dev->stats.rx_bytes += len;
L
Linus Torvalds 已提交
853

854
	return total_len;
855
}
L
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856

857 858
static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
			      unsigned long count, loff_t pos)
L
Linus Torvalds 已提交
859
{
860
	struct file *file = iocb->ki_filp;
H
Herbert Xu 已提交
861
	struct tun_struct *tun = tun_get(file);
E
Eric W. Biederman 已提交
862
	ssize_t result;
L
Linus Torvalds 已提交
863 864 865 866

	if (!tun)
		return -EBADFD;

867
	tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
L
Linus Torvalds 已提交
868

869
	result = tun_get_user(tun, NULL, iv, iov_length(iv, count), count,
870
			      file->f_flags & O_NONBLOCK);
E
Eric W. Biederman 已提交
871 872 873

	tun_put(tun);
	return result;
L
Linus Torvalds 已提交
874 875 876
}

/* Put packet to the user space buffer */
877 878 879
static ssize_t tun_put_user(struct tun_struct *tun,
			    struct sk_buff *skb,
			    const struct iovec *iv, int len)
L
Linus Torvalds 已提交
880 881 882 883 884 885 886 887 888 889 890 891
{
	struct tun_pi pi = { 0, skb->protocol };
	ssize_t total = 0;

	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;
		}
892

893
		if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
L
Linus Torvalds 已提交
894 895
			return -EFAULT;
		total += sizeof(pi);
896
	}
L
Linus Torvalds 已提交
897

898 899
	if (tun->flags & TUN_VNET_HDR) {
		struct virtio_net_hdr gso = { 0 }; /* no info leak */
900
		if ((len -= tun->vnet_hdr_sz) < 0)
901 902 903 904 905 906 907 908 909 910 911 912
			return -EINVAL;

		if (skb_is_gso(skb)) {
			struct skb_shared_info *sinfo = skb_shinfo(skb);

			/* This is a hint as to how much should be linear. */
			gso.hdr_len = skb_headlen(skb);
			gso.gso_size = sinfo->gso_size;
			if (sinfo->gso_type & SKB_GSO_TCPV4)
				gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
			else if (sinfo->gso_type & SKB_GSO_TCPV6)
				gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
913 914
			else if (sinfo->gso_type & SKB_GSO_UDP)
				gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
915
			else {
916
				pr_err("unexpected GSO type: "
917 918 919 920 921 922 923 924 925 926
				       "0x%x, gso_size %d, hdr_len %d\n",
				       sinfo->gso_type, gso.gso_size,
				       gso.hdr_len);
				print_hex_dump(KERN_ERR, "tun: ",
					       DUMP_PREFIX_NONE,
					       16, 1, skb->head,
					       min((int)gso.hdr_len, 64), true);
				WARN_ON_ONCE(1);
				return -EINVAL;
			}
927 928 929 930 931 932 933
			if (sinfo->gso_type & SKB_GSO_TCP_ECN)
				gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
		} else
			gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;

		if (skb->ip_summed == CHECKSUM_PARTIAL) {
			gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
934
			gso.csum_start = skb_checksum_start_offset(skb);
935
			gso.csum_offset = skb->csum_offset;
936 937
		} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
			gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
938 939
		} /* else everything is zero */

940 941
		if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
					       sizeof(gso))))
942
			return -EFAULT;
943
		total += tun->vnet_hdr_sz;
944 945
	}

L
Linus Torvalds 已提交
946 947
	len = min_t(int, skb->len, len);

948
	skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
949
	total += skb->len;
L
Linus Torvalds 已提交
950

951 952
	tun->dev->stats.tx_packets++;
	tun->dev->stats.tx_bytes += len;
L
Linus Torvalds 已提交
953 954 955 956

	return total;
}

957 958 959
static ssize_t tun_do_read(struct tun_struct *tun,
			   struct kiocb *iocb, const struct iovec *iv,
			   ssize_t len, int noblock)
L
Linus Torvalds 已提交
960 961 962
{
	DECLARE_WAITQUEUE(wait, current);
	struct sk_buff *skb;
963
	ssize_t ret = 0;
L
Linus Torvalds 已提交
964

965
	tun_debug(KERN_INFO, tun, "tun_chr_read\n");
L
Linus Torvalds 已提交
966

967 968
	if (unlikely(!noblock))
		add_wait_queue(&tun->wq.wait, &wait);
L
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969 970 971 972
	while (len) {
		current->state = TASK_INTERRUPTIBLE;

		/* Read frames from the queue */
973
		if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) {
974
			if (noblock) {
L
Linus Torvalds 已提交
975 976 977 978 979 980 981
				ret = -EAGAIN;
				break;
			}
			if (signal_pending(current)) {
				ret = -ERESTARTSYS;
				break;
			}
982 983 984 985
			if (tun->dev->reg_state != NETREG_REGISTERED) {
				ret = -EIO;
				break;
			}
L
Linus Torvalds 已提交
986 987 988 989 990 991 992

			/* Nothing to read, let's sleep */
			schedule();
			continue;
		}
		netif_wake_queue(tun->dev);

993
		ret = tun_put_user(tun, skb, iv, len);
994 995
		kfree_skb(skb);
		break;
L
Linus Torvalds 已提交
996 997 998
	}

	current->state = TASK_RUNNING;
999 1000
	if (unlikely(!noblock))
		remove_wait_queue(&tun->wq.wait, &wait);
L
Linus Torvalds 已提交
1001

1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022
	return ret;
}

static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
			    unsigned long count, loff_t pos)
{
	struct file *file = iocb->ki_filp;
	struct tun_file *tfile = file->private_data;
	struct tun_struct *tun = __tun_get(tfile);
	ssize_t len, ret;

	if (!tun)
		return -EBADFD;
	len = iov_length(iv, count);
	if (len < 0) {
		ret = -EINVAL;
		goto out;
	}

	ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK);
	ret = min_t(ssize_t, ret, len);
E
Eric W. Biederman 已提交
1023 1024
out:
	tun_put(tun);
L
Linus Torvalds 已提交
1025 1026 1027 1028 1029 1030 1031
	return ret;
}

static void tun_setup(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);

1032 1033
	tun->owner = INVALID_UID;
	tun->group = INVALID_GID;
L
Linus Torvalds 已提交
1034 1035

	dev->ethtool_ops = &tun_ethtool_ops;
1036
	dev->destructor = tun_free_netdev;
L
Linus Torvalds 已提交
1037 1038
}

1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053
/* Trivial set of netlink ops to allow deleting tun or tap
 * device with netlink.
 */
static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
{
	return -EINVAL;
}

static struct rtnl_link_ops tun_link_ops __read_mostly = {
	.kind		= DRV_NAME,
	.priv_size	= sizeof(struct tun_struct),
	.setup		= tun_setup,
	.validate	= tun_validate,
};

1054 1055 1056
static void tun_sock_write_space(struct sock *sk)
{
	struct tun_struct *tun;
1057
	wait_queue_head_t *wqueue;
1058 1059 1060 1061 1062 1063 1064

	if (!sock_writeable(sk))
		return;

	if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
		return;

1065 1066 1067
	wqueue = sk_sleep(sk);
	if (wqueue && waitqueue_active(wqueue))
		wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1068
						POLLWRNORM | POLLWRBAND);
H
Herbert Xu 已提交
1069

1070
	tun = tun_sk(sk)->tun;
1071 1072 1073 1074 1075
	kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
}

static void tun_sock_destruct(struct sock *sk)
{
1076
	free_netdev(tun_sk(sk)->tun->dev);
1077 1078
}

1079 1080 1081 1082
static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
		       struct msghdr *m, size_t total_len)
{
	struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
1083 1084
	return tun_get_user(tun, m->msg_control, m->msg_iov, total_len,
			    m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103
}

static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
		       struct msghdr *m, size_t total_len,
		       int flags)
{
	struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
	int ret;
	if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
		return -EINVAL;
	ret = tun_do_read(tun, iocb, m->msg_iov, total_len,
			  flags & MSG_DONTWAIT);
	if (ret > total_len) {
		m->msg_flags |= MSG_TRUNC;
		ret = flags & MSG_TRUNC ? ret : total_len;
	}
	return ret;
}

1104 1105 1106 1107 1108 1109 1110
static int tun_release(struct socket *sock)
{
	if (sock->sk)
		sock_put(sock->sk);
	return 0;
}

1111 1112 1113 1114
/* Ops structure to mimic raw sockets with tun */
static const struct proto_ops tun_socket_ops = {
	.sendmsg = tun_sendmsg,
	.recvmsg = tun_recvmsg,
1115
	.release = tun_release,
1116 1117
};

1118 1119 1120 1121 1122
static struct proto tun_proto = {
	.name		= "tun",
	.owner		= THIS_MODULE,
	.obj_size	= sizeof(struct tun_sock),
};
1123

1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155
static int tun_flags(struct tun_struct *tun)
{
	int flags = 0;

	if (tun->flags & TUN_TUN_DEV)
		flags |= IFF_TUN;
	else
		flags |= IFF_TAP;

	if (tun->flags & TUN_NO_PI)
		flags |= IFF_NO_PI;

	if (tun->flags & TUN_ONE_QUEUE)
		flags |= IFF_ONE_QUEUE;

	if (tun->flags & TUN_VNET_HDR)
		flags |= IFF_VNET_HDR;

	return flags;
}

static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
			      char *buf)
{
	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
	return sprintf(buf, "0x%x\n", tun_flags(tun));
}

static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
			      char *buf)
{
	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1156 1157 1158 1159
	return uid_valid(tun->owner)?
		sprintf(buf, "%u\n",
			from_kuid_munged(current_user_ns(), tun->owner)):
		sprintf(buf, "-1\n");
1160 1161 1162 1163 1164 1165
}

static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
			      char *buf)
{
	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1166 1167 1168 1169
	return gid_valid(tun->group) ?
		sprintf(buf, "%u\n",
			from_kgid_munged(current_user_ns(), tun->group)):
		sprintf(buf, "-1\n");
1170 1171 1172 1173 1174 1175
}

static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
static DEVICE_ATTR(group, 0444, tun_show_group, NULL);

1176
static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
L
Linus Torvalds 已提交
1177
{
1178
	struct sock *sk;
L
Linus Torvalds 已提交
1179 1180 1181 1182
	struct tun_struct *tun;
	struct net_device *dev;
	int err;

1183 1184
	dev = __dev_get_by_name(net, ifr->ifr_name);
	if (dev) {
P
Paul Moore 已提交
1185 1186
		const struct cred *cred = current_cred();

1187 1188
		if (ifr->ifr_flags & IFF_TUN_EXCL)
			return -EBUSY;
1189 1190 1191 1192 1193 1194 1195
		if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
			tun = netdev_priv(dev);
		else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
			tun = netdev_priv(dev);
		else
			return -EINVAL;

1196 1197
		if (((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
		     (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
P
Paul Moore 已提交
1198 1199
		    !capable(CAP_NET_ADMIN))
			return -EPERM;
1200
		err = security_tun_dev_attach(tun->socket.sk);
P
Paul Moore 已提交
1201 1202 1203
		if (err < 0)
			return err;

1204 1205 1206
		err = tun_attach(tun, file);
		if (err < 0)
			return err;
1207
	}
L
Linus Torvalds 已提交
1208 1209 1210 1211
	else {
		char *name;
		unsigned long flags = 0;

1212 1213
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;
P
Paul Moore 已提交
1214 1215 1216
		err = security_tun_dev_create();
		if (err < 0)
			return err;
1217

L
Linus Torvalds 已提交
1218 1219 1220 1221 1222 1223 1224 1225 1226
		/* Set dev type */
		if (ifr->ifr_flags & IFF_TUN) {
			/* TUN device */
			flags |= TUN_TUN_DEV;
			name = "tun%d";
		} else if (ifr->ifr_flags & IFF_TAP) {
			/* TAP device */
			flags |= TUN_TAP_DEV;
			name = "tap%d";
1227
		} else
1228
			return -EINVAL;
1229

L
Linus Torvalds 已提交
1230 1231 1232 1233 1234 1235 1236 1237
		if (*ifr->ifr_name)
			name = ifr->ifr_name;

		dev = alloc_netdev(sizeof(struct tun_struct), name,
				   tun_setup);
		if (!dev)
			return -ENOMEM;

1238
		dev_net_set(dev, net);
1239
		dev->rtnl_link_ops = &tun_link_ops;
S
Stephen Hemminger 已提交
1240

L
Linus Torvalds 已提交
1241 1242 1243
		tun = netdev_priv(dev);
		tun->dev = dev;
		tun->flags = flags;
1244
		tun->txflt.count = 0;
1245
		tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1246
		set_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags);
L
Linus Torvalds 已提交
1247

1248
		err = -ENOMEM;
1249
		sk = sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
1250 1251 1252
		if (!sk)
			goto err_free_dev;

1253
		sk_change_net(sk, net);
1254 1255
		tun->socket.wq = &tun->wq;
		init_waitqueue_head(&tun->wq.wait);
1256
		tun->socket.ops = &tun_socket_ops;
1257 1258 1259
		sock_init_data(&tun->socket, sk);
		sk->sk_write_space = tun_sock_write_space;
		sk->sk_sndbuf = INT_MAX;
1260
		sock_set_flag(sk, SOCK_ZEROCOPY);
1261

1262
		tun_sk(sk)->tun = tun;
1263

P
Paul Moore 已提交
1264 1265
		security_tun_dev_post_create(sk);

L
Linus Torvalds 已提交
1266 1267
		tun_net_init(dev);

1268 1269 1270 1271
		dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
			TUN_USER_FEATURES;
		dev->features = dev->hw_features;

L
Linus Torvalds 已提交
1272 1273
		err = register_netdevice(tun->dev);
		if (err < 0)
1274 1275
			goto err_free_sk;

1276 1277 1278
		if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
		    device_create_file(&tun->dev->dev, &dev_attr_owner) ||
		    device_create_file(&tun->dev->dev, &dev_attr_group))
1279
			pr_err("Failed to create tun sysfs files\n");
1280

1281
		sk->sk_destruct = tun_sock_destruct;
1282 1283 1284

		err = tun_attach(tun, file);
		if (err < 0)
1285
			goto failed;
L
Linus Torvalds 已提交
1286 1287
	}

1288
	tun_debug(KERN_INFO, tun, "tun_set_iff\n");
L
Linus Torvalds 已提交
1289 1290 1291

	if (ifr->ifr_flags & IFF_NO_PI)
		tun->flags |= TUN_NO_PI;
1292 1293
	else
		tun->flags &= ~TUN_NO_PI;
L
Linus Torvalds 已提交
1294 1295 1296

	if (ifr->ifr_flags & IFF_ONE_QUEUE)
		tun->flags |= TUN_ONE_QUEUE;
1297 1298
	else
		tun->flags &= ~TUN_ONE_QUEUE;
L
Linus Torvalds 已提交
1299

1300 1301 1302 1303 1304
	if (ifr->ifr_flags & IFF_VNET_HDR)
		tun->flags |= TUN_VNET_HDR;
	else
		tun->flags &= ~TUN_VNET_HDR;

1305 1306 1307 1308 1309 1310
	/* Make sure persistent devices do not get stuck in
	 * xoff state.
	 */
	if (netif_running(tun->dev))
		netif_wake_queue(tun->dev);

L
Linus Torvalds 已提交
1311 1312 1313
	strcpy(ifr->ifr_name, tun->dev->name);
	return 0;

1314
 err_free_sk:
1315
	tun_free_netdev(dev);
L
Linus Torvalds 已提交
1316 1317 1318 1319 1320 1321
 err_free_dev:
	free_netdev(dev);
 failed:
	return err;
}

1322 1323
static int tun_get_iff(struct net *net, struct tun_struct *tun,
		       struct ifreq *ifr)
1324
{
1325
	tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1326 1327 1328

	strcpy(ifr->ifr_name, tun->dev->name);

1329
	ifr->ifr_flags = tun_flags(tun);
1330 1331 1332 1333

	return 0;
}

1334 1335
/* This is like a cut-down ethtool ops, except done via tun fd so no
 * privs required. */
1336
static int set_offload(struct tun_struct *tun, unsigned long arg)
1337
{
1338
	netdev_features_t features = 0;
1339 1340

	if (arg & TUN_F_CSUM) {
1341
		features |= NETIF_F_HW_CSUM;
1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354
		arg &= ~TUN_F_CSUM;

		if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
			if (arg & TUN_F_TSO_ECN) {
				features |= NETIF_F_TSO_ECN;
				arg &= ~TUN_F_TSO_ECN;
			}
			if (arg & TUN_F_TSO4)
				features |= NETIF_F_TSO;
			if (arg & TUN_F_TSO6)
				features |= NETIF_F_TSO6;
			arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
		}
1355 1356 1357 1358 1359

		if (arg & TUN_F_UFO) {
			features |= NETIF_F_UFO;
			arg &= ~TUN_F_UFO;
		}
1360 1361 1362 1363 1364 1365 1366
	}

	/* This gives the user a way to test for new features in future by
	 * trying to set them. */
	if (arg)
		return -EINVAL;

1367 1368
	tun->set_features = features;
	netdev_update_features(tun->dev);
1369 1370 1371 1372

	return 0;
}

1373 1374
static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
			    unsigned long arg, int ifreq_len)
L
Linus Torvalds 已提交
1375
{
E
Eric W. Biederman 已提交
1376
	struct tun_file *tfile = file->private_data;
E
Eric W. Biederman 已提交
1377
	struct tun_struct *tun;
L
Linus Torvalds 已提交
1378
	void __user* argp = (void __user*)arg;
M
Michael S. Tsirkin 已提交
1379
	struct sock_fprog fprog;
L
Linus Torvalds 已提交
1380
	struct ifreq ifr;
1381 1382
	kuid_t owner;
	kgid_t group;
1383
	int sndbuf;
1384
	int vnet_hdr_sz;
1385
	int ret;
L
Linus Torvalds 已提交
1386

1387
	if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) {
1388
		if (copy_from_user(&ifr, argp, ifreq_len))
L
Linus Torvalds 已提交
1389
			return -EFAULT;
D
David S. Miller 已提交
1390
	} else {
1391
		memset(&ifr, 0, sizeof(ifr));
D
David S. Miller 已提交
1392
	}
E
Eric W. Biederman 已提交
1393 1394 1395 1396 1397 1398 1399 1400 1401
	if (cmd == TUNGETFEATURES) {
		/* Currently this just means: "what IFF flags are valid?".
		 * This is needed because we never checked for invalid flags on
		 * TUNSETIFF. */
		return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
				IFF_VNET_HDR,
				(unsigned int __user*)argp);
	}

1402 1403
	rtnl_lock();

E
Eric W. Biederman 已提交
1404
	tun = __tun_get(tfile);
L
Linus Torvalds 已提交
1405 1406 1407
	if (cmd == TUNSETIFF && !tun) {
		ifr.ifr_name[IFNAMSIZ-1] = '\0';

1408
		ret = tun_set_iff(tfile->net, file, &ifr);
L
Linus Torvalds 已提交
1409

1410 1411
		if (ret)
			goto unlock;
L
Linus Torvalds 已提交
1412

1413
		if (copy_to_user(argp, &ifr, ifreq_len))
1414 1415
			ret = -EFAULT;
		goto unlock;
L
Linus Torvalds 已提交
1416 1417
	}

1418
	ret = -EBADFD;
L
Linus Torvalds 已提交
1419
	if (!tun)
1420
		goto unlock;
L
Linus Torvalds 已提交
1421

1422
	tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
L
Linus Torvalds 已提交
1423

E
Eric W. Biederman 已提交
1424
	ret = 0;
L
Linus Torvalds 已提交
1425
	switch (cmd) {
1426
	case TUNGETIFF:
1427
		ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1428
		if (ret)
E
Eric W. Biederman 已提交
1429
			break;
1430

1431
		if (copy_to_user(argp, &ifr, ifreq_len))
E
Eric W. Biederman 已提交
1432
			ret = -EFAULT;
1433 1434
		break;

L
Linus Torvalds 已提交
1435 1436 1437
	case TUNSETNOCSUM:
		/* Disable/Enable checksum */

1438 1439
		/* [unimplemented] */
		tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1440
			  arg ? "disabled" : "enabled");
L
Linus Torvalds 已提交
1441 1442 1443 1444 1445 1446 1447 1448 1449
		break;

	case TUNSETPERSIST:
		/* Disable/Enable persist mode */
		if (arg)
			tun->flags |= TUN_PERSIST;
		else
			tun->flags &= ~TUN_PERSIST;

1450 1451
		tun_debug(KERN_INFO, tun, "persist %s\n",
			  arg ? "enabled" : "disabled");
L
Linus Torvalds 已提交
1452 1453 1454 1455
		break;

	case TUNSETOWNER:
		/* Set owner of the device */
1456 1457 1458 1459 1460 1461
		owner = make_kuid(current_user_ns(), arg);
		if (!uid_valid(owner)) {
			ret = -EINVAL;
			break;
		}
		tun->owner = owner;
1462
		tun_debug(KERN_INFO, tun, "owner set to %u\n",
1463
			  from_kuid(&init_user_ns, tun->owner));
L
Linus Torvalds 已提交
1464 1465
		break;

1466 1467
	case TUNSETGROUP:
		/* Set group of the device */
1468 1469 1470 1471 1472 1473
		group = make_kgid(current_user_ns(), arg);
		if (!gid_valid(group)) {
			ret = -EINVAL;
			break;
		}
		tun->group = group;
1474
		tun_debug(KERN_INFO, tun, "group set to %u\n",
1475
			  from_kgid(&init_user_ns, tun->group));
1476 1477
		break;

1478 1479 1480
	case TUNSETLINK:
		/* Only allow setting the type when the interface is down */
		if (tun->dev->flags & IFF_UP) {
1481 1482
			tun_debug(KERN_INFO, tun,
				  "Linktype set failed because interface is up\n");
1483
			ret = -EBUSY;
1484 1485
		} else {
			tun->dev->type = (int) arg;
1486 1487
			tun_debug(KERN_INFO, tun, "linktype set to %d\n",
				  tun->dev->type);
1488
			ret = 0;
1489
		}
E
Eric W. Biederman 已提交
1490
		break;
1491

L
Linus Torvalds 已提交
1492 1493 1494 1495 1496
#ifdef TUN_DEBUG
	case TUNSETDEBUG:
		tun->debug = arg;
		break;
#endif
1497
	case TUNSETOFFLOAD:
1498
		ret = set_offload(tun, arg);
E
Eric W. Biederman 已提交
1499
		break;
1500

1501 1502
	case TUNSETTXFILTER:
		/* Can be set only for TAPs */
E
Eric W. Biederman 已提交
1503
		ret = -EINVAL;
1504
		if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
E
Eric W. Biederman 已提交
1505
			break;
H
Harvey Harrison 已提交
1506
		ret = update_filter(&tun->txflt, (void __user *)arg);
E
Eric W. Biederman 已提交
1507
		break;
L
Linus Torvalds 已提交
1508 1509

	case SIOCGIFHWADDR:
1510
		/* Get hw address */
1511 1512
		memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
		ifr.ifr_hwaddr.sa_family = tun->dev->type;
1513
		if (copy_to_user(argp, &ifr, ifreq_len))
E
Eric W. Biederman 已提交
1514 1515
			ret = -EFAULT;
		break;
L
Linus Torvalds 已提交
1516 1517

	case SIOCSIFHWADDR:
1518
		/* Set hw address */
1519 1520
		tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
			  ifr.ifr_hwaddr.sa_data);
1521 1522

		ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
E
Eric W. Biederman 已提交
1523
		break;
1524 1525

	case TUNGETSNDBUF:
1526
		sndbuf = tun->socket.sk->sk_sndbuf;
1527 1528 1529 1530 1531 1532 1533 1534 1535 1536
		if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
			ret = -EFAULT;
		break;

	case TUNSETSNDBUF:
		if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
			ret = -EFAULT;
			break;
		}

1537
		tun->socket.sk->sk_sndbuf = sndbuf;
1538 1539
		break;

1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558
	case TUNGETVNETHDRSZ:
		vnet_hdr_sz = tun->vnet_hdr_sz;
		if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
			ret = -EFAULT;
		break;

	case TUNSETVNETHDRSZ:
		if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
			ret = -EFAULT;
			break;
		}
		if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
			ret = -EINVAL;
			break;
		}

		tun->vnet_hdr_sz = vnet_hdr_sz;
		break;

M
Michael S. Tsirkin 已提交
1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578
	case TUNATTACHFILTER:
		/* Can be set only for TAPs */
		ret = -EINVAL;
		if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
			break;
		ret = -EFAULT;
		if (copy_from_user(&fprog, argp, sizeof(fprog)))
			break;

		ret = sk_attach_filter(&fprog, tun->socket.sk);
		break;

	case TUNDETACHFILTER:
		/* Can be set only for TAPs */
		ret = -EINVAL;
		if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
			break;
		ret = sk_detach_filter(tun->socket.sk);
		break;

L
Linus Torvalds 已提交
1579
	default:
E
Eric W. Biederman 已提交
1580 1581
		ret = -EINVAL;
		break;
1582
	}
L
Linus Torvalds 已提交
1583

1584 1585 1586 1587
unlock:
	rtnl_unlock();
	if (tun)
		tun_put(tun);
E
Eric W. Biederman 已提交
1588
	return ret;
L
Linus Torvalds 已提交
1589 1590
}

1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625
static long tun_chr_ioctl(struct file *file,
			  unsigned int cmd, unsigned long arg)
{
	return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
}

#ifdef CONFIG_COMPAT
static long tun_chr_compat_ioctl(struct file *file,
			 unsigned int cmd, unsigned long arg)
{
	switch (cmd) {
	case TUNSETIFF:
	case TUNGETIFF:
	case TUNSETTXFILTER:
	case TUNGETSNDBUF:
	case TUNSETSNDBUF:
	case SIOCGIFHWADDR:
	case SIOCSIFHWADDR:
		arg = (unsigned long)compat_ptr(arg);
		break;
	default:
		arg = (compat_ulong_t)arg;
		break;
	}

	/*
	 * compat_ifreq is shorter than ifreq, so we must not access beyond
	 * the end of that structure. All fields that are used in this
	 * driver are compatible though, we don't need to convert the
	 * contents.
	 */
	return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
}
#endif /* CONFIG_COMPAT */

L
Linus Torvalds 已提交
1626 1627
static int tun_chr_fasync(int fd, struct file *file, int on)
{
E
Eric W. Biederman 已提交
1628
	struct tun_struct *tun = tun_get(file);
L
Linus Torvalds 已提交
1629 1630 1631 1632 1633
	int ret;

	if (!tun)
		return -EBADFD;

1634
	tun_debug(KERN_INFO, tun, "tun_chr_fasync %d\n", on);
L
Linus Torvalds 已提交
1635 1636

	if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
J
Jonathan Corbet 已提交
1637
		goto out;
1638

L
Linus Torvalds 已提交
1639
	if (on) {
1640
		ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
L
Linus Torvalds 已提交
1641
		if (ret)
J
Jonathan Corbet 已提交
1642
			goto out;
L
Linus Torvalds 已提交
1643
		tun->flags |= TUN_FASYNC;
1644
	} else
L
Linus Torvalds 已提交
1645
		tun->flags &= ~TUN_FASYNC;
J
Jonathan Corbet 已提交
1646 1647
	ret = 0;
out:
E
Eric W. Biederman 已提交
1648
	tun_put(tun);
J
Jonathan Corbet 已提交
1649
	return ret;
L
Linus Torvalds 已提交
1650 1651 1652 1653
}

static int tun_chr_open(struct inode *inode, struct file * file)
{
E
Eric W. Biederman 已提交
1654
	struct tun_file *tfile;
T
Thomas Gleixner 已提交
1655

1656
	DBG1(KERN_INFO, "tunX: tun_chr_open\n");
E
Eric W. Biederman 已提交
1657 1658 1659 1660

	tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
	if (!tfile)
		return -ENOMEM;
1661
	atomic_set(&tfile->count, 0);
E
Eric W. Biederman 已提交
1662
	tfile->tun = NULL;
E
Eric W. Biederman 已提交
1663
	tfile->net = get_net(current->nsproxy->net_ns);
E
Eric W. Biederman 已提交
1664
	file->private_data = tfile;
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	return 0;
}

static int tun_chr_close(struct inode *inode, struct file *file)
{
E
Eric W. Biederman 已提交
1670
	struct tun_file *tfile = file->private_data;
E
Eric W. Biederman 已提交
1671
	struct tun_struct *tun;
L
Linus Torvalds 已提交
1672

E
Eric W. Biederman 已提交
1673
	tun = __tun_get(tfile);
E
Eric W. Biederman 已提交
1674
	if (tun) {
H
Herbert Xu 已提交
1675 1676
		struct net_device *dev = tun->dev;

1677
		tun_debug(KERN_INFO, tun, "tun_chr_close\n");
L
Linus Torvalds 已提交
1678

E
Eric W. Biederman 已提交
1679
		__tun_detach(tun);
L
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1680

D
Daniel Mack 已提交
1681
		/* If desirable, unregister the netdevice. */
H
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		if (!(tun->flags & TUN_PERSIST)) {
			rtnl_lock();
			if (dev->reg_state == NETREG_REGISTERED)
				unregister_netdevice(dev);
			rtnl_unlock();
		}
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Eric W. Biederman 已提交
1688
	}
L
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1689

1690 1691
	tun = tfile->tun;
	if (tun)
1692
		sock_put(tun->socket.sk);
1693

E
Eric W. Biederman 已提交
1694
	put_net(tfile->net);
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1695
	kfree(tfile);
L
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	return 0;
}

1700
static const struct file_operations tun_fops = {
1701
	.owner	= THIS_MODULE,
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	.llseek = no_llseek,
1703 1704 1705 1706
	.read  = do_sync_read,
	.aio_read  = tun_chr_aio_read,
	.write = do_sync_write,
	.aio_write = tun_chr_aio_write,
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1707
	.poll	= tun_chr_poll,
1708 1709 1710 1711
	.unlocked_ioctl	= tun_chr_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = tun_chr_compat_ioctl,
#endif
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	.open	= tun_chr_open,
	.release = tun_chr_close,
1714
	.fasync = tun_chr_fasync
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};

static struct miscdevice tun_miscdev = {
	.minor = TUN_MINOR,
	.name = "tun",
1720
	.nodename = "net/tun",
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	.fops = &tun_fops,
};

/* ethtool interface */

static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
	cmd->supported		= 0;
	cmd->advertising	= 0;
1730
	ethtool_cmd_speed_set(cmd, SPEED_10);
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1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744
	cmd->duplex		= DUPLEX_FULL;
	cmd->port		= PORT_TP;
	cmd->phy_address	= 0;
	cmd->transceiver	= XCVR_INTERNAL;
	cmd->autoneg		= AUTONEG_DISABLE;
	cmd->maxtxpkt		= 0;
	cmd->maxrxpkt		= 0;
	return 0;
}

static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
	struct tun_struct *tun = netdev_priv(dev);

1745 1746
	strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
	strlcpy(info->version, DRV_VERSION, sizeof(info->version));
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	switch (tun->flags & TUN_TYPE_MASK) {
	case TUN_TUN_DEV:
1750
		strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
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		break;
	case TUN_TAP_DEV:
1753
		strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
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1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775
		break;
	}
}

static u32 tun_get_msglevel(struct net_device *dev)
{
#ifdef TUN_DEBUG
	struct tun_struct *tun = netdev_priv(dev);
	return tun->debug;
#else
	return -EOPNOTSUPP;
#endif
}

static void tun_set_msglevel(struct net_device *dev, u32 value)
{
#ifdef TUN_DEBUG
	struct tun_struct *tun = netdev_priv(dev);
	tun->debug = value;
#endif
}

1776
static const struct ethtool_ops tun_ethtool_ops = {
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	.get_settings	= tun_get_settings,
	.get_drvinfo	= tun_get_drvinfo,
	.get_msglevel	= tun_get_msglevel,
	.set_msglevel	= tun_set_msglevel,
1781
	.get_link	= ethtool_op_get_link,
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1782 1783
};

1784

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1785 1786 1787 1788
static int __init tun_init(void)
{
	int ret = 0;

1789 1790
	pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
	pr_info("%s\n", DRV_COPYRIGHT);
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1791

1792
	ret = rtnl_link_register(&tun_link_ops);
1793
	if (ret) {
1794
		pr_err("Can't register link_ops\n");
1795
		goto err_linkops;
1796 1797
	}

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1798
	ret = misc_register(&tun_miscdev);
1799
	if (ret) {
1800
		pr_err("Can't register misc device %d\n", TUN_MINOR);
1801 1802
		goto err_misc;
	}
1803
	return  0;
1804
err_misc:
1805 1806
	rtnl_link_unregister(&tun_link_ops);
err_linkops:
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1807 1808 1809 1810 1811
	return ret;
}

static void tun_cleanup(void)
{
1812
	misc_deregister(&tun_miscdev);
1813
	rtnl_link_unregister(&tun_link_ops);
L
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}

1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832
/* Get an underlying socket object from tun file.  Returns error unless file is
 * attached to a device.  The returned object works like a packet socket, it
 * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
 * holding a reference to the file for as long as the socket is in use. */
struct socket *tun_get_socket(struct file *file)
{
	struct tun_struct *tun;
	if (file->f_op != &tun_fops)
		return ERR_PTR(-EINVAL);
	tun = tun_get(file);
	if (!tun)
		return ERR_PTR(-EBADFD);
	tun_put(tun);
	return &tun->socket;
}
EXPORT_SYMBOL_GPL(tun_get_socket);

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module_init(tun_init);
module_exit(tun_cleanup);
MODULE_DESCRIPTION(DRV_DESCRIPTION);
MODULE_AUTHOR(DRV_COPYRIGHT);
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(TUN_MINOR);
1839
MODULE_ALIAS("devname:net/tun");