tun.c 53.8 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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/* DEFAULT_MAX_NUM_RSS_QUEUES were choosed to let the rx/tx queues allocated for
 * the netdevice to be fit in one page. So we can make sure the success of
 * memory allocation. TODO: increase the limit. */
#define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES
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#define MAX_TAP_FLOWS  4096
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#define TUN_FLOW_EXPIRE (3 * HZ)

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/* A tun_file connects an open character device to a tuntap netdevice. It
 * also contains all socket related strctures (except sock_fprog and tap_filter)
 * to serve as one transmit queue for tuntap device. The sock_fprog and
 * tap_filter were kept in tun_struct since they were used for filtering for the
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 * netdevice not for a specific queue (at least I didn't see the requirement for
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 * this).
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 *
 * RCU usage:
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 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
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 * other can only be read while rcu_read_lock or rtnl_lock is held.
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 */
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struct tun_file {
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	struct sock sk;
	struct socket socket;
	struct socket_wq wq;
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	struct tun_struct __rcu *tun;
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	struct net *net;
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	struct fasync_struct *fasync;
	/* only used for fasnyc */
	unsigned int flags;
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	u16 queue_index;
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	struct list_head next;
	struct tun_struct *detached;
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};

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struct tun_flow_entry {
	struct hlist_node hash_link;
	struct rcu_head rcu;
	struct tun_struct *tun;

	u32 rxhash;
	int queue_index;
	unsigned long updated;
};

#define TUN_NUM_FLOW_ENTRIES 1024

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/* Since the socket were moved to tun_file, to preserve the behavior of persist
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 * device, socket filter, sndbuf and vnet header size were restore when the
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 * file were attached to a persist device.
 */
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struct tun_struct {
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	struct tun_file __rcu	*tfiles[MAX_TAP_QUEUES];
	unsigned int            numqueues;
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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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	int			vnet_hdr_sz;
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	int			sndbuf;
	struct tap_filter	txflt;
	struct sock_fprog	fprog;
	/* protected by rtnl lock */
	bool			filter_attached;
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#ifdef TUN_DEBUG
	int debug;
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#endif
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	spinlock_t lock;
	struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
	struct timer_list flow_gc_timer;
	unsigned long ageing_time;
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	unsigned int numdisabled;
	struct list_head disabled;
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	void *security;
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	u32 flow_count;
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};
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static inline u32 tun_hashfn(u32 rxhash)
{
	return rxhash & 0x3ff;
}

static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
{
	struct tun_flow_entry *e;

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	hlist_for_each_entry_rcu(e, head, hash_link) {
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		if (e->rxhash == rxhash)
			return e;
	}
	return NULL;
}

static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
					      struct hlist_head *head,
					      u32 rxhash, u16 queue_index)
{
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	struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);

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	if (e) {
		tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
			  rxhash, queue_index);
		e->updated = jiffies;
		e->rxhash = rxhash;
		e->queue_index = queue_index;
		e->tun = tun;
		hlist_add_head_rcu(&e->hash_link, head);
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		++tun->flow_count;
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	}
	return e;
}

static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
{
	tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
		  e->rxhash, e->queue_index);
	hlist_del_rcu(&e->hash_link);
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	kfree_rcu(e, rcu);
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	--tun->flow_count;
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}

static void tun_flow_flush(struct tun_struct *tun)
{
	int i;

	spin_lock_bh(&tun->lock);
	for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
		struct tun_flow_entry *e;
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		struct hlist_node *n;
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		hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
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			tun_flow_delete(tun, e);
	}
	spin_unlock_bh(&tun->lock);
}

static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
{
	int i;

	spin_lock_bh(&tun->lock);
	for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
		struct tun_flow_entry *e;
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		struct hlist_node *n;
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		hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
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			if (e->queue_index == queue_index)
				tun_flow_delete(tun, e);
		}
	}
	spin_unlock_bh(&tun->lock);
}

static void tun_flow_cleanup(unsigned long data)
{
	struct tun_struct *tun = (struct tun_struct *)data;
	unsigned long delay = tun->ageing_time;
	unsigned long next_timer = jiffies + delay;
	unsigned long count = 0;
	int i;

	tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");

	spin_lock_bh(&tun->lock);
	for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
		struct tun_flow_entry *e;
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		struct hlist_node *n;
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		hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
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			unsigned long this_timer;
			count++;
			this_timer = e->updated + delay;
			if (time_before_eq(this_timer, jiffies))
				tun_flow_delete(tun, e);
			else if (time_before(this_timer, next_timer))
				next_timer = this_timer;
		}
	}

	if (count)
		mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
	spin_unlock_bh(&tun->lock);
}

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static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
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			    struct tun_file *tfile)
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{
	struct hlist_head *head;
	struct tun_flow_entry *e;
	unsigned long delay = tun->ageing_time;
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	u16 queue_index = tfile->queue_index;
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	if (!rxhash)
		return;
	else
		head = &tun->flows[tun_hashfn(rxhash)];

	rcu_read_lock();

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	/* We may get a very small possibility of OOO during switching, not
	 * worth to optimize.*/
	if (tun->numqueues == 1 || tfile->detached)
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		goto unlock;

	e = tun_flow_find(head, rxhash);
	if (likely(e)) {
		/* TODO: keep queueing to old queue until it's empty? */
		e->queue_index = queue_index;
		e->updated = jiffies;
	} else {
		spin_lock_bh(&tun->lock);
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		if (!tun_flow_find(head, rxhash) &&
		    tun->flow_count < MAX_TAP_FLOWS)
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			tun_flow_create(tun, head, rxhash, queue_index);

		if (!timer_pending(&tun->flow_gc_timer))
			mod_timer(&tun->flow_gc_timer,
				  round_jiffies_up(jiffies + delay));
		spin_unlock_bh(&tun->lock);
	}

unlock:
	rcu_read_unlock();
}

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/* We try to identify a flow through its rxhash first. The reason that
 * we do not check rxq no. is becuase some cards(e.g 82599), chooses
 * the rxq based on the txq where the last packet of the flow comes. As
 * the userspace application move between processors, we may get a
 * different rxq no. here. If we could not get rxhash, then we would
 * hope the rxq no. may help here.
 */
static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb)
{
	struct tun_struct *tun = netdev_priv(dev);
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	struct tun_flow_entry *e;
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	u32 txq = 0;
	u32 numqueues = 0;

	rcu_read_lock();
	numqueues = tun->numqueues;

	txq = skb_get_rxhash(skb);
	if (txq) {
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		e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
		if (e)
			txq = e->queue_index;
		else
			/* use multiply and shift instead of expensive divide */
			txq = ((u64)txq * numqueues) >> 32;
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	} else if (likely(skb_rx_queue_recorded(skb))) {
		txq = skb_get_rx_queue(skb);
		while (unlikely(txq >= numqueues))
			txq -= numqueues;
	}

	rcu_read_unlock();
	return txq;
}

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static inline bool tun_not_capable(struct tun_struct *tun)
{
	const struct cred *cred = current_cred();
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	struct net *net = dev_net(tun->dev);
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	return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
		  (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
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		!ns_capable(net->user_ns, CAP_NET_ADMIN);
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}

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static void tun_set_real_num_queues(struct tun_struct *tun)
{
	netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
	netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
}

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static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
{
	tfile->detached = tun;
	list_add_tail(&tfile->next, &tun->disabled);
	++tun->numdisabled;
}

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static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
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{
	struct tun_struct *tun = tfile->detached;

	tfile->detached = NULL;
	list_del_init(&tfile->next);
	--tun->numdisabled;
	return tun;
}

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static void __tun_detach(struct tun_file *tfile, bool clean)
{
	struct tun_file *ntfile;
	struct tun_struct *tun;
	struct net_device *dev;

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	tun = rtnl_dereference(tfile->tun);

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	if (tun && !tfile->detached) {
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		u16 index = tfile->queue_index;
		BUG_ON(index >= tun->numqueues);
		dev = tun->dev;

		rcu_assign_pointer(tun->tfiles[index],
				   tun->tfiles[tun->numqueues - 1]);
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		ntfile = rtnl_dereference(tun->tfiles[index]);
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		ntfile->queue_index = index;

		--tun->numqueues;
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		if (clean) {
			rcu_assign_pointer(tfile->tun, NULL);
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			sock_put(&tfile->sk);
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		} else
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			tun_disable_queue(tun, tfile);
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		synchronize_net();
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		tun_flow_delete_by_queue(tun, tun->numqueues + 1);
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		/* Drop read queue */
		skb_queue_purge(&tfile->sk.sk_receive_queue);
		tun_set_real_num_queues(tun);
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	} else if (tfile->detached && clean) {
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		tun = tun_enable_queue(tfile);
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		sock_put(&tfile->sk);
	}
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	if (clean) {
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		if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
			netif_carrier_off(tun->dev);

			if (!(tun->flags & TUN_PERSIST) &&
			    tun->dev->reg_state == NETREG_REGISTERED)
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				unregister_netdevice(tun->dev);
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		}
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		BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
				 &tfile->socket.flags));
		sk_release_kernel(&tfile->sk);
	}
}

static void tun_detach(struct tun_file *tfile, bool clean)
{
	rtnl_lock();
	__tun_detach(tfile, clean);
	rtnl_unlock();
}

static void tun_detach_all(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);
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	struct tun_file *tfile, *tmp;
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	int i, n = tun->numqueues;

	for (i = 0; i < n; i++) {
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		tfile = rtnl_dereference(tun->tfiles[i]);
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		BUG_ON(!tfile);
		wake_up_all(&tfile->wq.wait);
		rcu_assign_pointer(tfile->tun, NULL);
		--tun->numqueues;
	}
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	list_for_each_entry(tfile, &tun->disabled, next) {
		wake_up_all(&tfile->wq.wait);
		rcu_assign_pointer(tfile->tun, NULL);
	}
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	BUG_ON(tun->numqueues != 0);

	synchronize_net();
	for (i = 0; i < n; i++) {
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		tfile = rtnl_dereference(tun->tfiles[i]);
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		/* Drop read queue */
		skb_queue_purge(&tfile->sk.sk_receive_queue);
		sock_put(&tfile->sk);
	}
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	list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
		tun_enable_queue(tfile);
		skb_queue_purge(&tfile->sk.sk_receive_queue);
		sock_put(&tfile->sk);
	}
	BUG_ON(tun->numdisabled != 0);
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	if (tun->flags & TUN_PERSIST)
		module_put(THIS_MODULE);
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}

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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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	err = security_tun_dev_attach(tfile->socket.sk, tun->security);
	if (err < 0)
		goto out;

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	err = -EINVAL;
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	if (rtnl_dereference(tfile->tun) && !tfile->detached)
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		goto out;

	err = -EBUSY;
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	if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1)
		goto out;

	err = -E2BIG;
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	if (!tfile->detached &&
	    tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
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		goto out;

	err = 0;
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	/* Re-attach the filter to presist device */
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	if (tun->filter_attached == true) {
		err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
		if (!err)
			goto out;
	}
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	tfile->queue_index = tun->numqueues;
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	rcu_assign_pointer(tfile->tun, tun);
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	rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
	tun->numqueues++;
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	if (tfile->detached)
		tun_enable_queue(tfile);
	else
		sock_hold(&tfile->sk);

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	tun_set_real_num_queues(tun);
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	/* device is allowed to go away first, so no need to hold extra
	 * refcnt.
	 */

out:
	return err;
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}

static struct tun_struct *__tun_get(struct tun_file *tfile)
{
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	struct tun_struct *tun;
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	rcu_read_lock();
	tun = rcu_dereference(tfile->tun);
	if (tun)
		dev_hold(tun->dev);
	rcu_read_unlock();
561 562

	return tun;
E
Eric W. Biederman 已提交
563 564 565 566 567 568 569 570 571
}

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

static void tun_put(struct tun_struct *tun)
{
572
	dev_put(tun->dev);
E
Eric W. Biederman 已提交
573 574
}

575
/* TAP filtering */
576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624
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;

625 626
	/* Remaining multicast addresses are hashed,
	 * unicast will leave the filter disabled. */
627
	memset(filter->mask, 0, sizeof(filter->mask));
628 629 630 631 632
	for (; n < uf.count; n++) {
		if (!is_multicast_ether_addr(addr[n].u)) {
			err = 0; /* no filter */
			goto done;
		}
633
		addr_hash_set(filter->mask, addr[n].u);
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

	/* 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++)
663
		if (ether_addr_equal(eh->h_dest, filter->addr[i]))
664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684
			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);
}

L
Linus Torvalds 已提交
685 686
/* Network device part of the driver */

687
static const struct ethtool_ops tun_ethtool_ops;
L
Linus Torvalds 已提交
688

689 690 691
/* Net device detach from fd. */
static void tun_net_uninit(struct net_device *dev)
{
J
Jason Wang 已提交
692
	tun_detach_all(dev);
693 694
}

L
Linus Torvalds 已提交
695 696 697
/* Net device open. */
static int tun_net_open(struct net_device *dev)
{
J
Jason Wang 已提交
698
	netif_tx_start_all_queues(dev);
L
Linus Torvalds 已提交
699 700 701 702 703 704
	return 0;
}

/* Net device close. */
static int tun_net_close(struct net_device *dev)
{
J
Jason Wang 已提交
705
	netif_tx_stop_all_queues(dev);
L
Linus Torvalds 已提交
706 707 708 709
	return 0;
}

/* Net device start xmit */
710
static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
L
Linus Torvalds 已提交
711 712
{
	struct tun_struct *tun = netdev_priv(dev);
J
Jason Wang 已提交
713
	int txq = skb->queue_mapping;
714
	struct tun_file *tfile;
L
Linus Torvalds 已提交
715

716
	rcu_read_lock();
J
Jason Wang 已提交
717 718
	tfile = rcu_dereference(tun->tfiles[txq]);

L
Linus Torvalds 已提交
719
	/* Drop packet if interface is not attached */
J
Jason Wang 已提交
720
	if (txq >= tun->numqueues)
L
Linus Torvalds 已提交
721 722
		goto drop;

723 724
	tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);

J
Jason Wang 已提交
725 726
	BUG_ON(!tfile);

727 728 729 730 731 732
	/* 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;

J
Jason Wang 已提交
733 734
	if (tfile->socket.sk->sk_filter &&
	    sk_filter(tfile->socket.sk, skb))
M
Michael S. Tsirkin 已提交
735 736
		goto drop;

R
Rami Rosen 已提交
737
	/* Limit the number of packets queued by dividing txq length with the
J
Jason Wang 已提交
738 739
	 * number of queues.
	 */
J
Jason Wang 已提交
740
	if (skb_queue_len(&tfile->socket.sk->sk_receive_queue)
741 742
			  >= dev->tx_queue_len / tun->numqueues)
		goto drop;
L
Linus Torvalds 已提交
743

M
Michael S. Tsirkin 已提交
744 745
	/* Orphan the skb - required as we might hang on to it
	 * for indefinite time. */
M
Michael S. Tsirkin 已提交
746 747
	if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
		goto drop;
M
Michael S. Tsirkin 已提交
748 749
	skb_orphan(skb);

750
	/* Enqueue packet */
J
Jason Wang 已提交
751
	skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
L
Linus Torvalds 已提交
752 753

	/* Notify and wake up reader process */
J
Jason Wang 已提交
754 755 756
	if (tfile->flags & TUN_FASYNC)
		kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
	wake_up_interruptible_poll(&tfile->wq.wait, POLLIN |
757
				   POLLRDNORM | POLLRDBAND);
758 759

	rcu_read_unlock();
760
	return NETDEV_TX_OK;
L
Linus Torvalds 已提交
761 762

drop:
763
	dev->stats.tx_dropped++;
764
	skb_tx_error(skb);
L
Linus Torvalds 已提交
765
	kfree_skb(skb);
766
	rcu_read_unlock();
767
	return NETDEV_TX_OK;
L
Linus Torvalds 已提交
768 769
}

770
static void tun_net_mclist(struct net_device *dev)
L
Linus Torvalds 已提交
771
{
772 773 774 775 776
	/*
	 * 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.
	 */
L
Linus Torvalds 已提交
777 778
}

E
Ed Swierk 已提交
779 780 781 782 783 784 785 786 787 788 789 790
#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;
}

791 792
static netdev_features_t tun_net_fix_features(struct net_device *dev,
	netdev_features_t features)
793 794 795 796 797
{
	struct tun_struct *tun = netdev_priv(dev);

	return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
}
798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814
#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
S
Stephen Hemminger 已提交
815
static const struct net_device_ops tun_netdev_ops = {
816
	.ndo_uninit		= tun_net_uninit,
S
Stephen Hemminger 已提交
817 818
	.ndo_open		= tun_net_open,
	.ndo_stop		= tun_net_close,
819
	.ndo_start_xmit		= tun_net_xmit,
S
Stephen Hemminger 已提交
820
	.ndo_change_mtu		= tun_net_change_mtu,
821
	.ndo_fix_features	= tun_net_fix_features,
J
Jason Wang 已提交
822
	.ndo_select_queue	= tun_select_queue,
823 824 825
#ifdef CONFIG_NET_POLL_CONTROLLER
	.ndo_poll_controller	= tun_poll_controller,
#endif
S
Stephen Hemminger 已提交
826 827 828
};

static const struct net_device_ops tap_netdev_ops = {
829
	.ndo_uninit		= tun_net_uninit,
S
Stephen Hemminger 已提交
830 831
	.ndo_open		= tun_net_open,
	.ndo_stop		= tun_net_close,
832
	.ndo_start_xmit		= tun_net_xmit,
S
Stephen Hemminger 已提交
833
	.ndo_change_mtu		= tun_net_change_mtu,
834
	.ndo_fix_features	= tun_net_fix_features,
835
	.ndo_set_rx_mode	= tun_net_mclist,
S
Stephen Hemminger 已提交
836 837
	.ndo_set_mac_address	= eth_mac_addr,
	.ndo_validate_addr	= eth_validate_addr,
J
Jason Wang 已提交
838
	.ndo_select_queue	= tun_select_queue,
839 840 841
#ifdef CONFIG_NET_POLL_CONTROLLER
	.ndo_poll_controller	= tun_poll_controller,
#endif
S
Stephen Hemminger 已提交
842 843
};

J
Jason Wang 已提交
844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864
static int tun_flow_init(struct tun_struct *tun)
{
	int i;

	for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
		INIT_HLIST_HEAD(&tun->flows[i]);

	tun->ageing_time = TUN_FLOW_EXPIRE;
	setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
	mod_timer(&tun->flow_gc_timer,
		  round_jiffies_up(jiffies + tun->ageing_time));

	return 0;
}

static void tun_flow_uninit(struct tun_struct *tun)
{
	del_timer_sync(&tun->flow_gc_timer);
	tun_flow_flush(tun);
}

L
Linus Torvalds 已提交
865 866 867 868
/* Initialize net device. */
static void tun_net_init(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);
869

L
Linus Torvalds 已提交
870 871
	switch (tun->flags & TUN_TYPE_MASK) {
	case TUN_TUN_DEV:
S
Stephen Hemminger 已提交
872 873
		dev->netdev_ops = &tun_netdev_ops;

L
Linus Torvalds 已提交
874 875 876 877 878 879
		/* Point-to-Point TUN Device */
		dev->hard_header_len = 0;
		dev->addr_len = 0;
		dev->mtu = 1500;

		/* Zero header length */
880
		dev->type = ARPHRD_NONE;
L
Linus Torvalds 已提交
881 882 883 884 885
		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:
K
Kusanagi Kouichi 已提交
886
		dev->netdev_ops = &tap_netdev_ops;
L
Linus Torvalds 已提交
887 888
		/* Ethernet TAP Device */
		ether_setup(dev);
889
		dev->priv_flags &= ~IFF_TX_SKB_SHARING;
890
		dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
891

892
		eth_hw_addr_random(dev);
893

L
Linus Torvalds 已提交
894 895 896 897 898 899 900 901
		dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
		break;
	}
}

/* Character device part */

/* Poll */
J
Jason Wang 已提交
902
static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
903
{
904 905
	struct tun_file *tfile = file->private_data;
	struct tun_struct *tun = __tun_get(tfile);
906
	struct sock *sk;
907
	unsigned int mask = 0;
L
Linus Torvalds 已提交
908 909

	if (!tun)
910
		return POLLERR;
L
Linus Torvalds 已提交
911

J
Jason Wang 已提交
912
	sk = tfile->socket.sk;
913

914
	tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
L
Linus Torvalds 已提交
915

J
Jason Wang 已提交
916
	poll_wait(file, &tfile->wq.wait, wait);
917

918
	if (!skb_queue_empty(&sk->sk_receive_queue))
L
Linus Torvalds 已提交
919 920
		mask |= POLLIN | POLLRDNORM;

921 922 923 924 925
	if (sock_writeable(sk) ||
	    (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
	     sock_writeable(sk)))
		mask |= POLLOUT | POLLWRNORM;

926 927 928
	if (tun->dev->reg_state != NETREG_REGISTERED)
		mask = POLLERR;

E
Eric W. Biederman 已提交
929
	tun_put(tun);
L
Linus Torvalds 已提交
930 931 932
	return mask;
}

933 934
/* 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). */
J
Jason Wang 已提交
935
static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
936 937
				     size_t prepad, size_t len,
				     size_t linear, int noblock)
938
{
J
Jason Wang 已提交
939
	struct sock *sk = tfile->socket.sk;
940
	struct sk_buff *skb;
941
	int err;
942 943

	/* Under a page?  Don't bother with paged skb. */
H
Herbert Xu 已提交
944
	if (prepad + len < PAGE_SIZE || !linear)
945
		linear = len;
946

947 948
	skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
				   &err);
949
	if (!skb)
950
		return ERR_PTR(err);
951 952 953

	skb_reserve(skb, prepad);
	skb_put(skb, linear);
954 955
	skb->data_len = len - linear;
	skb->len += len - linear;
956 957 958 959

	return skb;
}

960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037
/* 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;
}

L
Linus Torvalds 已提交
1038
/* Get packet from user space buffer */
J
Jason Wang 已提交
1039 1040 1041
static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
			    void *msg_control, const struct iovec *iv,
			    size_t total_len, size_t count, int noblock)
L
Linus Torvalds 已提交
1042
{
1043
	struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
L
Linus Torvalds 已提交
1044
	struct sk_buff *skb;
1045
	size_t len = total_len, align = NET_SKB_PAD;
1046
	struct virtio_net_hdr gso = { 0 };
1047
	int offset = 0;
1048 1049 1050
	int copylen;
	bool zerocopy = false;
	int err;
1051
	u32 rxhash;
L
Linus Torvalds 已提交
1052 1053

	if (!(tun->flags & TUN_NO_PI)) {
1054
		if ((len -= sizeof(pi)) > total_len)
L
Linus Torvalds 已提交
1055 1056
			return -EINVAL;

1057
		if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
L
Linus Torvalds 已提交
1058
			return -EFAULT;
1059
		offset += sizeof(pi);
L
Linus Torvalds 已提交
1060 1061
	}

1062
	if (tun->flags & TUN_VNET_HDR) {
1063
		if ((len -= tun->vnet_hdr_sz) > total_len)
1064 1065
			return -EINVAL;

1066
		if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
1067 1068
			return -EFAULT;

1069 1070 1071 1072
		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;

1073 1074
		if (gso.hdr_len > len)
			return -EINVAL;
1075
		offset += tun->vnet_hdr_sz;
1076 1077
	}

1078
	if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
1079
		align += NET_IP_ALIGN;
H
Herbert Xu 已提交
1080 1081
		if (unlikely(len < ETH_HLEN ||
			     (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
1082 1083
			return -EINVAL;
	}
1084

1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111
	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;

J
Jason Wang 已提交
1112
	skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, noblock);
1113 1114 1115 1116
	if (IS_ERR(skb)) {
		if (PTR_ERR(skb) != -EAGAIN)
			tun->dev->stats.rx_dropped++;
		return PTR_ERR(skb);
L
Linus Torvalds 已提交
1117 1118
	}

1119 1120 1121 1122 1123 1124
	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) {
1125
		tun->dev->stats.rx_dropped++;
D
Dave Jones 已提交
1126
		kfree_skb(skb);
L
Linus Torvalds 已提交
1127
		return -EFAULT;
D
Dave Jones 已提交
1128
	}
L
Linus Torvalds 已提交
1129

1130 1131 1132 1133 1134 1135 1136
	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;
		}
1137
	}
1138

L
Linus Torvalds 已提交
1139 1140
	switch (tun->flags & TUN_TYPE_MASK) {
	case TUN_TUN_DEV:
1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155
		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;
			}
		}

1156
		skb_reset_mac_header(skb);
L
Linus Torvalds 已提交
1157
		skb->protocol = pi.proto;
1158
		skb->dev = tun->dev;
L
Linus Torvalds 已提交
1159 1160 1161 1162
		break;
	case TUN_TAP_DEV:
		skb->protocol = eth_type_trans(skb, tun->dev);
		break;
1163
	}
L
Linus Torvalds 已提交
1164

1165 1166 1167 1168
	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:
1169
			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1170 1171
			break;
		case VIRTIO_NET_HDR_GSO_TCPV6:
1172
			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1173
			break;
1174
		case VIRTIO_NET_HDR_GSO_UDP:
1175
			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1176
			break;
1177 1178 1179 1180 1181 1182 1183
		default:
			tun->dev->stats.rx_frame_errors++;
			kfree_skb(skb);
			return -EINVAL;
		}

		if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1184
			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196

		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;
	}
1197

1198 1199 1200 1201
	/* 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;
1202
		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1203 1204
	}

1205
	skb_reset_network_header(skb);
1206
	rxhash = skb_get_rxhash(skb);
L
Linus Torvalds 已提交
1207
	netif_rx_ni(skb);
1208

1209 1210
	tun->dev->stats.rx_packets++;
	tun->dev->stats.rx_bytes += len;
L
Linus Torvalds 已提交
1211

1212
	tun_flow_update(tun, rxhash, tfile);
1213
	return total_len;
1214
}
L
Linus Torvalds 已提交
1215

1216 1217
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
1218
{
1219
	struct file *file = iocb->ki_filp;
H
Herbert Xu 已提交
1220
	struct tun_struct *tun = tun_get(file);
J
Jason Wang 已提交
1221
	struct tun_file *tfile = file->private_data;
E
Eric W. Biederman 已提交
1222
	ssize_t result;
L
Linus Torvalds 已提交
1223 1224 1225 1226

	if (!tun)
		return -EBADFD;

1227
	tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
L
Linus Torvalds 已提交
1228

J
Jason Wang 已提交
1229 1230
	result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count),
			      count, file->f_flags & O_NONBLOCK);
E
Eric W. Biederman 已提交
1231 1232 1233

	tun_put(tun);
	return result;
L
Linus Torvalds 已提交
1234 1235 1236
}

/* Put packet to the user space buffer */
1237
static ssize_t tun_put_user(struct tun_struct *tun,
J
Jason Wang 已提交
1238
			    struct tun_file *tfile,
1239 1240
			    struct sk_buff *skb,
			    const struct iovec *iv, int len)
L
Linus Torvalds 已提交
1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252
{
	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;
		}
1253

1254
		if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
L
Linus Torvalds 已提交
1255 1256
			return -EFAULT;
		total += sizeof(pi);
1257
	}
L
Linus Torvalds 已提交
1258

1259 1260
	if (tun->flags & TUN_VNET_HDR) {
		struct virtio_net_hdr gso = { 0 }; /* no info leak */
1261
		if ((len -= tun->vnet_hdr_sz) < 0)
1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273
			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;
1274 1275
			else if (sinfo->gso_type & SKB_GSO_UDP)
				gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1276
			else {
1277
				pr_err("unexpected GSO type: "
1278 1279 1280 1281 1282 1283 1284 1285 1286 1287
				       "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;
			}
1288 1289 1290 1291 1292 1293 1294
			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;
1295
			gso.csum_start = skb_checksum_start_offset(skb);
1296
			gso.csum_offset = skb->csum_offset;
1297 1298
		} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
			gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1299 1300
		} /* else everything is zero */

1301 1302
		if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
					       sizeof(gso))))
1303
			return -EFAULT;
1304
		total += tun->vnet_hdr_sz;
1305 1306
	}

L
Linus Torvalds 已提交
1307 1308
	len = min_t(int, skb->len, len);

1309
	skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
1310
	total += skb->len;
L
Linus Torvalds 已提交
1311

1312 1313
	tun->dev->stats.tx_packets++;
	tun->dev->stats.tx_bytes += len;
L
Linus Torvalds 已提交
1314 1315 1316 1317

	return total;
}

J
Jason Wang 已提交
1318
static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1319 1320
			   struct kiocb *iocb, const struct iovec *iv,
			   ssize_t len, int noblock)
L
Linus Torvalds 已提交
1321 1322 1323
{
	DECLARE_WAITQUEUE(wait, current);
	struct sk_buff *skb;
1324
	ssize_t ret = 0;
L
Linus Torvalds 已提交
1325

1326
	tun_debug(KERN_INFO, tun, "tun_do_read\n");
L
Linus Torvalds 已提交
1327

1328
	if (unlikely(!noblock))
J
Jason Wang 已提交
1329
		add_wait_queue(&tfile->wq.wait, &wait);
L
Linus Torvalds 已提交
1330 1331 1332 1333
	while (len) {
		current->state = TASK_INTERRUPTIBLE;

		/* Read frames from the queue */
J
Jason Wang 已提交
1334
		if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) {
1335
			if (noblock) {
L
Linus Torvalds 已提交
1336 1337 1338 1339 1340 1341 1342
				ret = -EAGAIN;
				break;
			}
			if (signal_pending(current)) {
				ret = -ERESTARTSYS;
				break;
			}
1343 1344 1345 1346
			if (tun->dev->reg_state != NETREG_REGISTERED) {
				ret = -EIO;
				break;
			}
L
Linus Torvalds 已提交
1347 1348 1349 1350 1351 1352

			/* Nothing to read, let's sleep */
			schedule();
			continue;
		}

J
Jason Wang 已提交
1353
		ret = tun_put_user(tun, tfile, skb, iv, len);
1354 1355
		kfree_skb(skb);
		break;
L
Linus Torvalds 已提交
1356 1357 1358
	}

	current->state = TASK_RUNNING;
1359
	if (unlikely(!noblock))
J
Jason Wang 已提交
1360
		remove_wait_queue(&tfile->wq.wait, &wait);
L
Linus Torvalds 已提交
1361

1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380
	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;
	}

J
Jason Wang 已提交
1381 1382
	ret = tun_do_read(tun, tfile, iocb, iv, len,
			  file->f_flags & O_NONBLOCK);
1383
	ret = min_t(ssize_t, ret, len);
E
Eric W. Biederman 已提交
1384 1385
out:
	tun_put(tun);
L
Linus Torvalds 已提交
1386 1387 1388
	return ret;
}

J
Jason Wang 已提交
1389 1390 1391 1392
static void tun_free_netdev(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);

J
Jason Wang 已提交
1393
	BUG_ON(!(list_empty(&tun->disabled)));
J
Jason Wang 已提交
1394
	tun_flow_uninit(tun);
1395
	security_tun_dev_free_security(tun->security);
J
Jason Wang 已提交
1396 1397 1398
	free_netdev(dev);
}

L
Linus Torvalds 已提交
1399 1400 1401 1402
static void tun_setup(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);

1403 1404
	tun->owner = INVALID_UID;
	tun->group = INVALID_GID;
L
Linus Torvalds 已提交
1405 1406

	dev->ethtool_ops = &tun_ethtool_ops;
J
Jason Wang 已提交
1407
	dev->destructor = tun_free_netdev;
L
Linus Torvalds 已提交
1408 1409
}

1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424
/* 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,
};

1425 1426
static void tun_sock_write_space(struct sock *sk)
{
J
Jason Wang 已提交
1427
	struct tun_file *tfile;
1428
	wait_queue_head_t *wqueue;
1429 1430 1431 1432 1433 1434 1435

	if (!sock_writeable(sk))
		return;

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

1436 1437 1438
	wqueue = sk_sleep(sk);
	if (wqueue && waitqueue_active(wqueue))
		wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1439
						POLLWRNORM | POLLWRBAND);
H
Herbert Xu 已提交
1440

J
Jason Wang 已提交
1441 1442
	tfile = container_of(sk, struct tun_file, sk);
	kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1443 1444
}

1445 1446 1447
static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
		       struct msghdr *m, size_t total_len)
{
J
Jason Wang 已提交
1448 1449 1450 1451 1452 1453 1454 1455 1456 1457
	int ret;
	struct tun_file *tfile = container_of(sock, struct tun_file, socket);
	struct tun_struct *tun = __tun_get(tfile);

	if (!tun)
		return -EBADFD;
	ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len,
			   m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
	tun_put(tun);
	return ret;
1458 1459
}

J
Jason Wang 已提交
1460

1461 1462 1463 1464
static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
		       struct msghdr *m, size_t total_len,
		       int flags)
{
J
Jason Wang 已提交
1465 1466
	struct tun_file *tfile = container_of(sock, struct tun_file, socket);
	struct tun_struct *tun = __tun_get(tfile);
1467
	int ret;
J
Jason Wang 已提交
1468 1469 1470 1471

	if (!tun)
		return -EBADFD;

1472 1473
	if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
		return -EINVAL;
J
Jason Wang 已提交
1474
	ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len,
1475 1476 1477 1478 1479
			  flags & MSG_DONTWAIT);
	if (ret > total_len) {
		m->msg_flags |= MSG_TRUNC;
		ret = flags & MSG_TRUNC ? ret : total_len;
	}
J
Jason Wang 已提交
1480
	tun_put(tun);
1481 1482 1483
	return ret;
}

1484 1485 1486 1487 1488 1489 1490
static int tun_release(struct socket *sock)
{
	if (sock->sk)
		sock_put(sock->sk);
	return 0;
}

1491 1492 1493 1494
/* Ops structure to mimic raw sockets with tun */
static const struct proto_ops tun_socket_ops = {
	.sendmsg = tun_sendmsg,
	.recvmsg = tun_recvmsg,
1495
	.release = tun_release,
1496 1497
};

1498 1499 1500
static struct proto tun_proto = {
	.name		= "tun",
	.owner		= THIS_MODULE,
J
Jason Wang 已提交
1501
	.obj_size	= sizeof(struct tun_file),
1502
};
1503

1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515
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;

1516 1517 1518
	/* This flag has no real effect.  We track the value for backwards
	 * compatibility.
	 */
1519 1520 1521 1522 1523 1524
	if (tun->flags & TUN_ONE_QUEUE)
		flags |= IFF_ONE_QUEUE;

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

J
Jason Wang 已提交
1525 1526 1527
	if (tun->flags & TUN_TAP_MQ)
		flags |= IFF_MULTI_QUEUE;

1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541
	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));
1542 1543 1544 1545
	return uid_valid(tun->owner)?
		sprintf(buf, "%u\n",
			from_kuid_munged(current_user_ns(), tun->owner)):
		sprintf(buf, "-1\n");
1546 1547 1548 1549 1550 1551
}

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));
1552 1553 1554 1555
	return gid_valid(tun->group) ?
		sprintf(buf, "%u\n",
			from_kgid_munged(current_user_ns(), tun->group)):
		sprintf(buf, "-1\n");
1556 1557 1558 1559 1560 1561
}

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);

1562
static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
L
Linus Torvalds 已提交
1563 1564
{
	struct tun_struct *tun;
J
Jason Wang 已提交
1565
	struct tun_file *tfile = file->private_data;
L
Linus Torvalds 已提交
1566 1567 1568
	struct net_device *dev;
	int err;

1569 1570 1571
	if (tfile->detached)
		return -EINVAL;

1572 1573
	dev = __dev_get_by_name(net, ifr->ifr_name);
	if (dev) {
1574 1575
		if (ifr->ifr_flags & IFF_TUN_EXCL)
			return -EBUSY;
1576 1577 1578 1579 1580 1581 1582
		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;

1583
		if (tun_not_capable(tun))
P
Paul Moore 已提交
1584
			return -EPERM;
1585
		err = security_tun_dev_open(tun->security);
P
Paul Moore 已提交
1586 1587 1588
		if (err < 0)
			return err;

1589 1590 1591
		err = tun_attach(tun, file);
		if (err < 0)
			return err;
J
Jason Wang 已提交
1592 1593 1594 1595

		if (tun->flags & TUN_TAP_MQ &&
		    (tun->numqueues + tun->numdisabled > 1))
			return err;
1596
	}
L
Linus Torvalds 已提交
1597 1598 1599
	else {
		char *name;
		unsigned long flags = 0;
1600 1601
		int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
			     MAX_TAP_QUEUES : 1;
L
Linus Torvalds 已提交
1602

1603
		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1604
			return -EPERM;
P
Paul Moore 已提交
1605 1606 1607
		err = security_tun_dev_create();
		if (err < 0)
			return err;
1608

L
Linus Torvalds 已提交
1609 1610 1611 1612 1613 1614 1615 1616 1617
		/* 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";
1618
		} else
1619
			return -EINVAL;
1620

L
Linus Torvalds 已提交
1621 1622 1623
		if (*ifr->ifr_name)
			name = ifr->ifr_name;

J
Jason Wang 已提交
1624
		dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1625 1626
				       tun_setup, queues, queues);

L
Linus Torvalds 已提交
1627 1628 1629
		if (!dev)
			return -ENOMEM;

1630
		dev_net_set(dev, net);
1631
		dev->rtnl_link_ops = &tun_link_ops;
S
Stephen Hemminger 已提交
1632

L
Linus Torvalds 已提交
1633 1634 1635
		tun = netdev_priv(dev);
		tun->dev = dev;
		tun->flags = flags;
1636
		tun->txflt.count = 0;
1637
		tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1638

J
Jason Wang 已提交
1639 1640
		tun->filter_attached = false;
		tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1641

J
Jason Wang 已提交
1642 1643
		spin_lock_init(&tun->lock);

1644 1645 1646
		err = security_tun_dev_alloc_security(&tun->security);
		if (err < 0)
			goto err_free_dev;
P
Paul Moore 已提交
1647

L
Linus Torvalds 已提交
1648 1649
		tun_net_init(dev);

1650 1651
		err = tun_flow_init(tun);
		if (err < 0)
J
Jason Wang 已提交
1652 1653
			goto err_free_dev;

1654 1655 1656 1657
		dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
			TUN_USER_FEATURES;
		dev->features = dev->hw_features;

J
Jason Wang 已提交
1658
		INIT_LIST_HEAD(&tun->disabled);
1659 1660 1661 1662
		err = tun_attach(tun, file);
		if (err < 0)
			goto err_free_dev;

L
Linus Torvalds 已提交
1663 1664
		err = register_netdevice(tun->dev);
		if (err < 0)
J
Jason Wang 已提交
1665
			goto err_free_dev;
1666

1667 1668 1669
		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))
1670
			pr_err("Failed to create tun sysfs files\n");
L
Linus Torvalds 已提交
1671 1672
	}

1673 1674
	netif_carrier_on(tun->dev);

1675
	tun_debug(KERN_INFO, tun, "tun_set_iff\n");
L
Linus Torvalds 已提交
1676 1677 1678

	if (ifr->ifr_flags & IFF_NO_PI)
		tun->flags |= TUN_NO_PI;
1679 1680
	else
		tun->flags &= ~TUN_NO_PI;
L
Linus Torvalds 已提交
1681

1682 1683 1684
	/* This flag has no real effect.  We track the value for backwards
	 * compatibility.
	 */
L
Linus Torvalds 已提交
1685 1686
	if (ifr->ifr_flags & IFF_ONE_QUEUE)
		tun->flags |= TUN_ONE_QUEUE;
1687 1688
	else
		tun->flags &= ~TUN_ONE_QUEUE;
L
Linus Torvalds 已提交
1689

1690 1691 1692 1693 1694
	if (ifr->ifr_flags & IFF_VNET_HDR)
		tun->flags |= TUN_VNET_HDR;
	else
		tun->flags &= ~TUN_VNET_HDR;

J
Jason Wang 已提交
1695 1696 1697 1698 1699
	if (ifr->ifr_flags & IFF_MULTI_QUEUE)
		tun->flags |= TUN_TAP_MQ;
	else
		tun->flags &= ~TUN_TAP_MQ;

1700 1701 1702 1703
	/* Make sure persistent devices do not get stuck in
	 * xoff state.
	 */
	if (netif_running(tun->dev))
J
Jason Wang 已提交
1704
		netif_tx_wake_all_queues(tun->dev);
1705

L
Linus Torvalds 已提交
1706 1707 1708 1709 1710 1711 1712 1713
	strcpy(ifr->ifr_name, tun->dev->name);
	return 0;

 err_free_dev:
	free_netdev(dev);
	return err;
}

R
Rami Rosen 已提交
1714
static void tun_get_iff(struct net *net, struct tun_struct *tun,
1715
		       struct ifreq *ifr)
1716
{
1717
	tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1718 1719 1720

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

1721
	ifr->ifr_flags = tun_flags(tun);
1722 1723 1724

}

1725 1726
/* This is like a cut-down ethtool ops, except done via tun fd so no
 * privs required. */
1727
static int set_offload(struct tun_struct *tun, unsigned long arg)
1728
{
1729
	netdev_features_t features = 0;
1730 1731

	if (arg & TUN_F_CSUM) {
1732
		features |= NETIF_F_HW_CSUM;
1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745
		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);
		}
1746 1747 1748 1749 1750

		if (arg & TUN_F_UFO) {
			features |= NETIF_F_UFO;
			arg &= ~TUN_F_UFO;
		}
1751 1752 1753 1754 1755 1756 1757
	}

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

1758 1759
	tun->set_features = features;
	netdev_update_features(tun->dev);
1760 1761 1762 1763

	return 0;
}

J
Jason Wang 已提交
1764 1765 1766 1767 1768 1769
static void tun_detach_filter(struct tun_struct *tun, int n)
{
	int i;
	struct tun_file *tfile;

	for (i = 0; i < n; i++) {
1770
		tfile = rtnl_dereference(tun->tfiles[i]);
J
Jason Wang 已提交
1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782
		sk_detach_filter(tfile->socket.sk);
	}

	tun->filter_attached = false;
}

static int tun_attach_filter(struct tun_struct *tun)
{
	int i, ret = 0;
	struct tun_file *tfile;

	for (i = 0; i < tun->numqueues; i++) {
1783
		tfile = rtnl_dereference(tun->tfiles[i]);
J
Jason Wang 已提交
1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800
		ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
		if (ret) {
			tun_detach_filter(tun, i);
			return ret;
		}
	}

	tun->filter_attached = true;
	return ret;
}

static void tun_set_sndbuf(struct tun_struct *tun)
{
	struct tun_file *tfile;
	int i;

	for (i = 0; i < tun->numqueues; i++) {
1801
		tfile = rtnl_dereference(tun->tfiles[i]);
J
Jason Wang 已提交
1802 1803 1804 1805
		tfile->socket.sk->sk_sndbuf = tun->sndbuf;
	}
}

1806 1807 1808 1809 1810 1811 1812 1813 1814
static int tun_set_queue(struct file *file, struct ifreq *ifr)
{
	struct tun_file *tfile = file->private_data;
	struct tun_struct *tun;
	int ret = 0;

	rtnl_lock();

	if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
J
Jason Wang 已提交
1815
		tun = tfile->detached;
1816
		if (!tun) {
1817
			ret = -EINVAL;
1818 1819 1820 1821 1822 1823
			goto unlock;
		}
		ret = security_tun_dev_attach_queue(tun->security);
		if (ret < 0)
			goto unlock;
		ret = tun_attach(tun, file);
J
Jason Wang 已提交
1824
	} else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1825
		tun = rtnl_dereference(tfile->tun);
1826
		if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached)
J
Jason Wang 已提交
1827 1828 1829 1830
			ret = -EINVAL;
		else
			__tun_detach(tfile, false);
	} else
1831 1832
		ret = -EINVAL;

1833
unlock:
1834 1835 1836 1837
	rtnl_unlock();
	return ret;
}

1838 1839
static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
			    unsigned long arg, int ifreq_len)
L
Linus Torvalds 已提交
1840
{
E
Eric W. Biederman 已提交
1841
	struct tun_file *tfile = file->private_data;
E
Eric W. Biederman 已提交
1842
	struct tun_struct *tun;
L
Linus Torvalds 已提交
1843 1844
	void __user* argp = (void __user*)arg;
	struct ifreq ifr;
1845 1846
	kuid_t owner;
	kgid_t group;
1847
	int sndbuf;
1848
	int vnet_hdr_sz;
1849
	int ret;
L
Linus Torvalds 已提交
1850

1851
	if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1852
		if (copy_from_user(&ifr, argp, ifreq_len))
L
Linus Torvalds 已提交
1853
			return -EFAULT;
D
David S. Miller 已提交
1854
	} else {
1855
		memset(&ifr, 0, sizeof(ifr));
D
David S. Miller 已提交
1856
	}
E
Eric W. Biederman 已提交
1857 1858 1859 1860 1861
	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 |
1862
				IFF_VNET_HDR | IFF_MULTI_QUEUE,
E
Eric W. Biederman 已提交
1863
				(unsigned int __user*)argp);
1864 1865
	} else if (cmd == TUNSETQUEUE)
		return tun_set_queue(file, &ifr);
E
Eric W. Biederman 已提交
1866

J
Jason Wang 已提交
1867
	ret = 0;
1868 1869
	rtnl_lock();

E
Eric W. Biederman 已提交
1870
	tun = __tun_get(tfile);
L
Linus Torvalds 已提交
1871 1872 1873
	if (cmd == TUNSETIFF && !tun) {
		ifr.ifr_name[IFNAMSIZ-1] = '\0';

1874
		ret = tun_set_iff(tfile->net, file, &ifr);
L
Linus Torvalds 已提交
1875

1876 1877
		if (ret)
			goto unlock;
L
Linus Torvalds 已提交
1878

1879
		if (copy_to_user(argp, &ifr, ifreq_len))
1880 1881
			ret = -EFAULT;
		goto unlock;
L
Linus Torvalds 已提交
1882 1883
	}

1884
	ret = -EBADFD;
L
Linus Torvalds 已提交
1885
	if (!tun)
1886
		goto unlock;
L
Linus Torvalds 已提交
1887

1888
	tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
L
Linus Torvalds 已提交
1889

E
Eric W. Biederman 已提交
1890
	ret = 0;
L
Linus Torvalds 已提交
1891
	switch (cmd) {
1892
	case TUNGETIFF:
R
Rami Rosen 已提交
1893
		tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1894

1895
		if (copy_to_user(argp, &ifr, ifreq_len))
E
Eric W. Biederman 已提交
1896
			ret = -EFAULT;
1897 1898
		break;

L
Linus Torvalds 已提交
1899 1900 1901
	case TUNSETNOCSUM:
		/* Disable/Enable checksum */

1902 1903
		/* [unimplemented] */
		tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1904
			  arg ? "disabled" : "enabled");
L
Linus Torvalds 已提交
1905 1906 1907
		break;

	case TUNSETPERSIST:
J
Jason Wang 已提交
1908 1909 1910
		/* Disable/Enable persist mode. Keep an extra reference to the
		 * module to prevent the module being unprobed.
		 */
J
Jason Wang 已提交
1911
		if (arg && !(tun->flags & TUN_PERSIST)) {
L
Linus Torvalds 已提交
1912
			tun->flags |= TUN_PERSIST;
J
Jason Wang 已提交
1913
			__module_get(THIS_MODULE);
J
Jason Wang 已提交
1914 1915
		}
		if (!arg && (tun->flags & TUN_PERSIST)) {
L
Linus Torvalds 已提交
1916
			tun->flags &= ~TUN_PERSIST;
J
Jason Wang 已提交
1917 1918
			module_put(THIS_MODULE);
		}
L
Linus Torvalds 已提交
1919

1920 1921
		tun_debug(KERN_INFO, tun, "persist %s\n",
			  arg ? "enabled" : "disabled");
L
Linus Torvalds 已提交
1922 1923 1924 1925
		break;

	case TUNSETOWNER:
		/* Set owner of the device */
1926 1927 1928 1929 1930 1931
		owner = make_kuid(current_user_ns(), arg);
		if (!uid_valid(owner)) {
			ret = -EINVAL;
			break;
		}
		tun->owner = owner;
1932
		tun_debug(KERN_INFO, tun, "owner set to %u\n",
1933
			  from_kuid(&init_user_ns, tun->owner));
L
Linus Torvalds 已提交
1934 1935
		break;

1936 1937
	case TUNSETGROUP:
		/* Set group of the device */
1938 1939 1940 1941 1942 1943
		group = make_kgid(current_user_ns(), arg);
		if (!gid_valid(group)) {
			ret = -EINVAL;
			break;
		}
		tun->group = group;
1944
		tun_debug(KERN_INFO, tun, "group set to %u\n",
1945
			  from_kgid(&init_user_ns, tun->group));
1946 1947
		break;

1948 1949 1950
	case TUNSETLINK:
		/* Only allow setting the type when the interface is down */
		if (tun->dev->flags & IFF_UP) {
1951 1952
			tun_debug(KERN_INFO, tun,
				  "Linktype set failed because interface is up\n");
1953
			ret = -EBUSY;
1954 1955
		} else {
			tun->dev->type = (int) arg;
1956 1957
			tun_debug(KERN_INFO, tun, "linktype set to %d\n",
				  tun->dev->type);
1958
			ret = 0;
1959
		}
E
Eric W. Biederman 已提交
1960
		break;
1961

L
Linus Torvalds 已提交
1962 1963 1964 1965 1966
#ifdef TUN_DEBUG
	case TUNSETDEBUG:
		tun->debug = arg;
		break;
#endif
1967
	case TUNSETOFFLOAD:
1968
		ret = set_offload(tun, arg);
E
Eric W. Biederman 已提交
1969
		break;
1970

1971 1972
	case TUNSETTXFILTER:
		/* Can be set only for TAPs */
E
Eric W. Biederman 已提交
1973
		ret = -EINVAL;
1974
		if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
E
Eric W. Biederman 已提交
1975
			break;
H
Harvey Harrison 已提交
1976
		ret = update_filter(&tun->txflt, (void __user *)arg);
E
Eric W. Biederman 已提交
1977
		break;
L
Linus Torvalds 已提交
1978 1979

	case SIOCGIFHWADDR:
1980
		/* Get hw address */
1981 1982
		memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
		ifr.ifr_hwaddr.sa_family = tun->dev->type;
1983
		if (copy_to_user(argp, &ifr, ifreq_len))
E
Eric W. Biederman 已提交
1984 1985
			ret = -EFAULT;
		break;
L
Linus Torvalds 已提交
1986 1987

	case SIOCSIFHWADDR:
1988
		/* Set hw address */
1989 1990
		tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
			  ifr.ifr_hwaddr.sa_data);
1991 1992

		ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
E
Eric W. Biederman 已提交
1993
		break;
1994 1995

	case TUNGETSNDBUF:
J
Jason Wang 已提交
1996
		sndbuf = tfile->socket.sk->sk_sndbuf;
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
		if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
			ret = -EFAULT;
		break;

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

J
Jason Wang 已提交
2007 2008
		tun->sndbuf = sndbuf;
		tun_set_sndbuf(tun);
2009 2010
		break;

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029
	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
2030 2031 2032 2033 2034 2035
	case TUNATTACHFILTER:
		/* Can be set only for TAPs */
		ret = -EINVAL;
		if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
			break;
		ret = -EFAULT;
J
Jason Wang 已提交
2036
		if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
M
Michael S. Tsirkin 已提交
2037 2038
			break;

J
Jason Wang 已提交
2039
		ret = tun_attach_filter(tun);
M
Michael S. Tsirkin 已提交
2040 2041 2042 2043 2044 2045 2046
		break;

	case TUNDETACHFILTER:
		/* Can be set only for TAPs */
		ret = -EINVAL;
		if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
			break;
J
Jason Wang 已提交
2047 2048
		ret = 0;
		tun_detach_filter(tun, tun->numqueues);
M
Michael S. Tsirkin 已提交
2049 2050
		break;

L
Linus Torvalds 已提交
2051
	default:
E
Eric W. Biederman 已提交
2052 2053
		ret = -EINVAL;
		break;
2054
	}
L
Linus Torvalds 已提交
2055

2056 2057 2058 2059
unlock:
	rtnl_unlock();
	if (tun)
		tun_put(tun);
E
Eric W. Biederman 已提交
2060
	return ret;
L
Linus Torvalds 已提交
2061 2062
}

2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097
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
2098 2099
static int tun_chr_fasync(int fd, struct file *file, int on)
{
J
Jason Wang 已提交
2100
	struct tun_file *tfile = file->private_data;
L
Linus Torvalds 已提交
2101 2102
	int ret;

J
Jason Wang 已提交
2103
	if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
J
Jonathan Corbet 已提交
2104
		goto out;
2105

L
Linus Torvalds 已提交
2106
	if (on) {
2107
		ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
L
Linus Torvalds 已提交
2108
		if (ret)
J
Jonathan Corbet 已提交
2109
			goto out;
J
Jason Wang 已提交
2110
		tfile->flags |= TUN_FASYNC;
2111
	} else
J
Jason Wang 已提交
2112
		tfile->flags &= ~TUN_FASYNC;
J
Jonathan Corbet 已提交
2113 2114 2115
	ret = 0;
out:
	return ret;
L
Linus Torvalds 已提交
2116 2117 2118 2119
}

static int tun_chr_open(struct inode *inode, struct file * file)
{
E
Eric W. Biederman 已提交
2120
	struct tun_file *tfile;
T
Thomas Gleixner 已提交
2121

2122
	DBG1(KERN_INFO, "tunX: tun_chr_open\n");
E
Eric W. Biederman 已提交
2123

J
Jason Wang 已提交
2124 2125
	tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
					    &tun_proto);
E
Eric W. Biederman 已提交
2126 2127
	if (!tfile)
		return -ENOMEM;
2128
	rcu_assign_pointer(tfile->tun, NULL);
E
Eric W. Biederman 已提交
2129
	tfile->net = get_net(current->nsproxy->net_ns);
J
Jason Wang 已提交
2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143
	tfile->flags = 0;

	rcu_assign_pointer(tfile->socket.wq, &tfile->wq);
	init_waitqueue_head(&tfile->wq.wait);

	tfile->socket.file = file;
	tfile->socket.ops = &tun_socket_ops;

	sock_init_data(&tfile->socket, &tfile->sk);
	sk_change_net(&tfile->sk, tfile->net);

	tfile->sk.sk_write_space = tun_sock_write_space;
	tfile->sk.sk_sndbuf = INT_MAX;

E
Eric W. Biederman 已提交
2144
	file->private_data = tfile;
J
Jason Wang 已提交
2145
	set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
J
Jason Wang 已提交
2146
	INIT_LIST_HEAD(&tfile->next);
J
Jason Wang 已提交
2147

L
Linus Torvalds 已提交
2148 2149 2150 2151 2152
	return 0;
}

static int tun_chr_close(struct inode *inode, struct file *file)
{
E
Eric W. Biederman 已提交
2153
	struct tun_file *tfile = file->private_data;
J
Jason Wang 已提交
2154
	struct net *net = tfile->net;
L
Linus Torvalds 已提交
2155

J
Jason Wang 已提交
2156
	tun_detach(tfile, true);
J
Jason Wang 已提交
2157
	put_net(net);
L
Linus Torvalds 已提交
2158 2159 2160 2161

	return 0;
}

2162
static const struct file_operations tun_fops = {
2163
	.owner	= THIS_MODULE,
L
Linus Torvalds 已提交
2164
	.llseek = no_llseek,
2165 2166 2167 2168
	.read  = do_sync_read,
	.aio_read  = tun_chr_aio_read,
	.write = do_sync_write,
	.aio_write = tun_chr_aio_write,
L
Linus Torvalds 已提交
2169
	.poll	= tun_chr_poll,
2170 2171 2172 2173
	.unlocked_ioctl	= tun_chr_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = tun_chr_compat_ioctl,
#endif
L
Linus Torvalds 已提交
2174 2175
	.open	= tun_chr_open,
	.release = tun_chr_close,
2176
	.fasync = tun_chr_fasync
L
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2177 2178 2179 2180 2181
};

static struct miscdevice tun_miscdev = {
	.minor = TUN_MINOR,
	.name = "tun",
2182
	.nodename = "net/tun",
L
Linus Torvalds 已提交
2183 2184 2185 2186 2187 2188 2189 2190 2191
	.fops = &tun_fops,
};

/* ethtool interface */

static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
	cmd->supported		= 0;
	cmd->advertising	= 0;
2192
	ethtool_cmd_speed_set(cmd, SPEED_10);
L
Linus Torvalds 已提交
2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206
	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);

2207 2208
	strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
	strlcpy(info->version, DRV_VERSION, sizeof(info->version));
L
Linus Torvalds 已提交
2209 2210 2211

	switch (tun->flags & TUN_TYPE_MASK) {
	case TUN_TUN_DEV:
2212
		strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
L
Linus Torvalds 已提交
2213 2214
		break;
	case TUN_TAP_DEV:
2215
		strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
L
Linus Torvalds 已提交
2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237
		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
}

2238
static const struct ethtool_ops tun_ethtool_ops = {
L
Linus Torvalds 已提交
2239 2240 2241 2242
	.get_settings	= tun_get_settings,
	.get_drvinfo	= tun_get_drvinfo,
	.get_msglevel	= tun_get_msglevel,
	.set_msglevel	= tun_set_msglevel,
2243
	.get_link	= ethtool_op_get_link,
L
Linus Torvalds 已提交
2244 2245
};

2246

L
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2247 2248 2249 2250
static int __init tun_init(void)
{
	int ret = 0;

2251 2252
	pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
	pr_info("%s\n", DRV_COPYRIGHT);
L
Linus Torvalds 已提交
2253

2254
	ret = rtnl_link_register(&tun_link_ops);
2255
	if (ret) {
2256
		pr_err("Can't register link_ops\n");
2257
		goto err_linkops;
2258 2259
	}

L
Linus Torvalds 已提交
2260
	ret = misc_register(&tun_miscdev);
2261
	if (ret) {
2262
		pr_err("Can't register misc device %d\n", TUN_MINOR);
2263 2264
		goto err_misc;
	}
2265
	return  0;
2266
err_misc:
2267 2268
	rtnl_link_unregister(&tun_link_ops);
err_linkops:
L
Linus Torvalds 已提交
2269 2270 2271 2272 2273
	return ret;
}

static void tun_cleanup(void)
{
2274
	misc_deregister(&tun_miscdev);
2275
	rtnl_link_unregister(&tun_link_ops);
L
Linus Torvalds 已提交
2276 2277
}

2278 2279 2280 2281 2282 2283
/* 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)
{
2284
	struct tun_file *tfile;
2285 2286
	if (file->f_op != &tun_fops)
		return ERR_PTR(-EINVAL);
2287 2288
	tfile = file->private_data;
	if (!tfile)
2289
		return ERR_PTR(-EBADFD);
J
Jason Wang 已提交
2290
	return &tfile->socket;
2291 2292 2293
}
EXPORT_SYMBOL_GPL(tun_get_socket);

L
Linus Torvalds 已提交
2294 2295 2296 2297 2298 2299
module_init(tun_init);
module_exit(tun_cleanup);
MODULE_DESCRIPTION(DRV_DESCRIPTION);
MODULE_AUTHOR(DRV_COPYRIGHT);
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(TUN_MINOR);
2300
MODULE_ALIAS("devname:net/tun");