2 * TUN - Universal TUN/TAP device driver.
3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
22 * Add TUNSETLINK ioctl to set the link encapsulation
24 * Mark Smith <markzzzsmith@yahoo.com.au>
25 * Use eth_random_addr() for tap MAC address.
27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
28 * Fixes in packet dropping, queue length setting and queue wakeup.
29 * Increased default tx queue length.
33 * Daniel Podlejski <underley@underley.eu.org>
34 * Modifications for 2.3.99-pre5 kernel.
37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
39 #define DRV_NAME "tun"
40 #define DRV_VERSION "1.6"
41 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
42 #define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
44 #include <linux/module.h>
45 #include <linux/errno.h>
46 #include <linux/kernel.h>
47 #include <linux/major.h>
48 #include <linux/slab.h>
49 #include <linux/poll.h>
50 #include <linux/fcntl.h>
51 #include <linux/init.h>
52 #include <linux/skbuff.h>
53 #include <linux/netdevice.h>
54 #include <linux/etherdevice.h>
55 #include <linux/miscdevice.h>
56 #include <linux/ethtool.h>
57 #include <linux/rtnetlink.h>
58 #include <linux/compat.h>
60 #include <linux/if_arp.h>
61 #include <linux/if_ether.h>
62 #include <linux/if_tun.h>
63 #include <linux/crc32.h>
64 #include <linux/nsproxy.h>
65 #include <linux/virtio_net.h>
66 #include <linux/rcupdate.h>
67 #include <net/net_namespace.h>
68 #include <net/netns/generic.h>
69 #include <net/rtnetlink.h>
72 #include <asm/uaccess.h>
74 /* Uncomment to enable debugging */
75 /* #define TUN_DEBUG 1 */
80 #define tun_debug(level, tun, fmt, args...) \
83 netdev_printk(level, tun->dev, fmt, ##args); \
85 #define DBG1(level, fmt, args...) \
88 printk(level fmt, ##args); \
91 #define tun_debug(level, tun, fmt, args...) \
94 netdev_printk(level, tun->dev, fmt, ##args); \
96 #define DBG1(level, fmt, args...) \
99 printk(level fmt, ##args); \
103 #define GOODCOPY_LEN 128
105 #define FLT_EXACT_COUNT 8
107 unsigned int count; /* Number of addrs. Zero means disabled */
108 u32 mask[2]; /* Mask of the hashed addrs */
109 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
112 /* 1024 is probably a high enough limit: modern hypervisors seem to support on
113 * the order of 100-200 CPUs so this leaves us some breathing space if we want
114 * to match a queue per guest CPU.
116 #define MAX_TAP_QUEUES 1024
118 #define TUN_FLOW_EXPIRE (3 * HZ)
120 /* A tun_file connects an open character device to a tuntap netdevice. It
121 * also contains all socket related strctures (except sock_fprog and tap_filter)
122 * to serve as one transmit queue for tuntap device. The sock_fprog and
123 * tap_filter were kept in tun_struct since they were used for filtering for the
124 * netdevice not for a specific queue (at least I didn't see the reqirement for
128 * The tun_file and tun_struct are loosely coupled, the pointer from on to the
129 * other can only be read while rcu_read_lock or rtnl_lock is held.
133 struct socket socket;
135 struct tun_struct __rcu *tun;
137 struct fasync_struct *fasync;
138 /* only used for fasnyc */
143 struct tun_flow_entry {
144 struct hlist_node hash_link;
146 struct tun_struct *tun;
150 unsigned long updated;
153 #define TUN_NUM_FLOW_ENTRIES 1024
155 /* Since the socket were moved to tun_file, to preserve the behavior of persist
156 * device, socket fileter, sndbuf and vnet header size were restore when the
157 * file were attached to a persist device.
160 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
161 unsigned int numqueues;
166 struct net_device *dev;
167 netdev_features_t set_features;
168 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
169 NETIF_F_TSO6|NETIF_F_UFO)
173 struct tap_filter txflt;
174 struct sock_fprog fprog;
175 /* protected by rtnl lock */
176 bool filter_attached;
181 struct kmem_cache *flow_cache;
182 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
183 struct timer_list flow_gc_timer;
184 unsigned long ageing_time;
187 static inline u32 tun_hashfn(u32 rxhash)
189 return rxhash & 0x3ff;
192 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
194 struct tun_flow_entry *e;
195 struct hlist_node *n;
197 hlist_for_each_entry_rcu(e, n, head, hash_link) {
198 if (e->rxhash == rxhash)
204 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
205 struct hlist_head *head,
206 u32 rxhash, u16 queue_index)
208 struct tun_flow_entry *e = kmem_cache_alloc(tun->flow_cache,
211 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
212 rxhash, queue_index);
213 e->updated = jiffies;
215 e->queue_index = queue_index;
217 hlist_add_head_rcu(&e->hash_link, head);
222 static void tun_flow_free(struct rcu_head *head)
224 struct tun_flow_entry *e
225 = container_of(head, struct tun_flow_entry, rcu);
226 kmem_cache_free(e->tun->flow_cache, e);
229 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
231 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
232 e->rxhash, e->queue_index);
233 hlist_del_rcu(&e->hash_link);
234 call_rcu(&e->rcu, tun_flow_free);
237 static void tun_flow_flush(struct tun_struct *tun)
241 spin_lock_bh(&tun->lock);
242 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
243 struct tun_flow_entry *e;
244 struct hlist_node *h, *n;
246 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link)
247 tun_flow_delete(tun, e);
249 spin_unlock_bh(&tun->lock);
252 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
256 spin_lock_bh(&tun->lock);
257 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
258 struct tun_flow_entry *e;
259 struct hlist_node *h, *n;
261 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link) {
262 if (e->queue_index == queue_index)
263 tun_flow_delete(tun, e);
266 spin_unlock_bh(&tun->lock);
269 static void tun_flow_cleanup(unsigned long data)
271 struct tun_struct *tun = (struct tun_struct *)data;
272 unsigned long delay = tun->ageing_time;
273 unsigned long next_timer = jiffies + delay;
274 unsigned long count = 0;
277 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
279 spin_lock_bh(&tun->lock);
280 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
281 struct tun_flow_entry *e;
282 struct hlist_node *h, *n;
284 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link) {
285 unsigned long this_timer;
287 this_timer = e->updated + delay;
288 if (time_before_eq(this_timer, jiffies))
289 tun_flow_delete(tun, e);
290 else if (time_before(this_timer, next_timer))
291 next_timer = this_timer;
296 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
297 spin_unlock_bh(&tun->lock);
300 static void tun_flow_update(struct tun_struct *tun, struct sk_buff *skb,
303 struct hlist_head *head;
304 struct tun_flow_entry *e;
305 unsigned long delay = tun->ageing_time;
306 u32 rxhash = skb_get_rxhash(skb);
311 head = &tun->flows[tun_hashfn(rxhash)];
315 if (tun->numqueues == 1)
318 e = tun_flow_find(head, rxhash);
320 /* TODO: keep queueing to old queue until it's empty? */
321 e->queue_index = queue_index;
322 e->updated = jiffies;
324 spin_lock_bh(&tun->lock);
325 if (!tun_flow_find(head, rxhash))
326 tun_flow_create(tun, head, rxhash, queue_index);
328 if (!timer_pending(&tun->flow_gc_timer))
329 mod_timer(&tun->flow_gc_timer,
330 round_jiffies_up(jiffies + delay));
331 spin_unlock_bh(&tun->lock);
338 /* We try to identify a flow through its rxhash first. The reason that
339 * we do not check rxq no. is becuase some cards(e.g 82599), chooses
340 * the rxq based on the txq where the last packet of the flow comes. As
341 * the userspace application move between processors, we may get a
342 * different rxq no. here. If we could not get rxhash, then we would
343 * hope the rxq no. may help here.
345 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb)
347 struct tun_struct *tun = netdev_priv(dev);
348 struct tun_flow_entry *e;
353 numqueues = tun->numqueues;
355 txq = skb_get_rxhash(skb);
357 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
359 txq = e->queue_index;
361 /* use multiply and shift instead of expensive divide */
362 txq = ((u64)txq * numqueues) >> 32;
363 } else if (likely(skb_rx_queue_recorded(skb))) {
364 txq = skb_get_rx_queue(skb);
365 while (unlikely(txq >= numqueues))
373 static inline bool tun_not_capable(struct tun_struct *tun)
375 const struct cred *cred = current_cred();
377 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
378 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
379 !capable(CAP_NET_ADMIN);
382 static void tun_set_real_num_queues(struct tun_struct *tun)
384 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
385 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
388 static void __tun_detach(struct tun_file *tfile, bool clean)
390 struct tun_file *ntfile;
391 struct tun_struct *tun;
392 struct net_device *dev;
394 tun = rcu_dereference_protected(tfile->tun,
395 lockdep_rtnl_is_held());
397 u16 index = tfile->queue_index;
398 BUG_ON(index >= tun->numqueues);
401 rcu_assign_pointer(tun->tfiles[index],
402 tun->tfiles[tun->numqueues - 1]);
403 rcu_assign_pointer(tfile->tun, NULL);
404 ntfile = rcu_dereference_protected(tun->tfiles[index],
405 lockdep_rtnl_is_held());
406 ntfile->queue_index = index;
409 sock_put(&tfile->sk);
412 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
413 /* Drop read queue */
414 skb_queue_purge(&tfile->sk.sk_receive_queue);
415 tun_set_real_num_queues(tun);
417 if (tun->numqueues == 0 && !(tun->flags & TUN_PERSIST))
418 if (dev->reg_state == NETREG_REGISTERED)
419 unregister_netdevice(dev);
423 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
424 &tfile->socket.flags));
425 sk_release_kernel(&tfile->sk);
429 static void tun_detach(struct tun_file *tfile, bool clean)
432 __tun_detach(tfile, clean);
436 static void tun_detach_all(struct net_device *dev)
438 struct tun_struct *tun = netdev_priv(dev);
439 struct tun_file *tfile;
440 int i, n = tun->numqueues;
442 for (i = 0; i < n; i++) {
443 tfile = rcu_dereference_protected(tun->tfiles[i],
444 lockdep_rtnl_is_held());
446 wake_up_all(&tfile->wq.wait);
447 rcu_assign_pointer(tfile->tun, NULL);
450 BUG_ON(tun->numqueues != 0);
453 for (i = 0; i < n; i++) {
454 tfile = rcu_dereference_protected(tun->tfiles[i],
455 lockdep_rtnl_is_held());
456 /* Drop read queue */
457 skb_queue_purge(&tfile->sk.sk_receive_queue);
458 sock_put(&tfile->sk);
462 static int tun_attach(struct tun_struct *tun, struct file *file)
464 struct tun_file *tfile = file->private_data;
468 if (rcu_dereference_protected(tfile->tun, lockdep_rtnl_is_held()))
472 if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1)
476 if (tun->numqueues == MAX_TAP_QUEUES)
481 /* Re-attach the filter to presist device */
482 if (tun->filter_attached == true) {
483 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
487 tfile->queue_index = tun->numqueues;
488 rcu_assign_pointer(tfile->tun, tun);
489 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
490 sock_hold(&tfile->sk);
493 tun_set_real_num_queues(tun);
495 if (tun->numqueues == 1)
496 netif_carrier_on(tun->dev);
498 /* device is allowed to go away first, so no need to hold extra
506 static struct tun_struct *__tun_get(struct tun_file *tfile)
508 struct tun_struct *tun;
511 tun = rcu_dereference(tfile->tun);
519 static struct tun_struct *tun_get(struct file *file)
521 return __tun_get(file->private_data);
524 static void tun_put(struct tun_struct *tun)
530 static void addr_hash_set(u32 *mask, const u8 *addr)
532 int n = ether_crc(ETH_ALEN, addr) >> 26;
533 mask[n >> 5] |= (1 << (n & 31));
536 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
538 int n = ether_crc(ETH_ALEN, addr) >> 26;
539 return mask[n >> 5] & (1 << (n & 31));
542 static int update_filter(struct tap_filter *filter, void __user *arg)
544 struct { u8 u[ETH_ALEN]; } *addr;
545 struct tun_filter uf;
546 int err, alen, n, nexact;
548 if (copy_from_user(&uf, arg, sizeof(uf)))
557 alen = ETH_ALEN * uf.count;
558 addr = kmalloc(alen, GFP_KERNEL);
562 if (copy_from_user(addr, arg + sizeof(uf), alen)) {
567 /* The filter is updated without holding any locks. Which is
568 * perfectly safe. We disable it first and in the worst
569 * case we'll accept a few undesired packets. */
573 /* Use first set of addresses as an exact filter */
574 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
575 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
579 /* Remaining multicast addresses are hashed,
580 * unicast will leave the filter disabled. */
581 memset(filter->mask, 0, sizeof(filter->mask));
582 for (; n < uf.count; n++) {
583 if (!is_multicast_ether_addr(addr[n].u)) {
584 err = 0; /* no filter */
587 addr_hash_set(filter->mask, addr[n].u);
590 /* For ALLMULTI just set the mask to all ones.
591 * This overrides the mask populated above. */
592 if ((uf.flags & TUN_FLT_ALLMULTI))
593 memset(filter->mask, ~0, sizeof(filter->mask));
595 /* Now enable the filter */
597 filter->count = nexact;
599 /* Return the number of exact filters */
607 /* Returns: 0 - drop, !=0 - accept */
608 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
610 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
612 struct ethhdr *eh = (struct ethhdr *) skb->data;
616 for (i = 0; i < filter->count; i++)
617 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
620 /* Inexact match (multicast only) */
621 if (is_multicast_ether_addr(eh->h_dest))
622 return addr_hash_test(filter->mask, eh->h_dest);
628 * Checks whether the packet is accepted or not.
629 * Returns: 0 - drop, !=0 - accept
631 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
636 return run_filter(filter, skb);
639 /* Network device part of the driver */
641 static const struct ethtool_ops tun_ethtool_ops;
643 /* Net device detach from fd. */
644 static void tun_net_uninit(struct net_device *dev)
649 /* Net device open. */
650 static int tun_net_open(struct net_device *dev)
652 netif_tx_start_all_queues(dev);
656 /* Net device close. */
657 static int tun_net_close(struct net_device *dev)
659 netif_tx_stop_all_queues(dev);
663 /* Net device start xmit */
664 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
666 struct tun_struct *tun = netdev_priv(dev);
667 int txq = skb->queue_mapping;
668 struct tun_file *tfile;
671 tfile = rcu_dereference(tun->tfiles[txq]);
673 /* Drop packet if interface is not attached */
674 if (txq >= tun->numqueues)
677 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
681 /* Drop if the filter does not like it.
682 * This is a noop if the filter is disabled.
683 * Filter can be enabled only for the TAP devices. */
684 if (!check_filter(&tun->txflt, skb))
687 if (tfile->socket.sk->sk_filter &&
688 sk_filter(tfile->socket.sk, skb))
691 /* Limit the number of packets queued by divining txq length with the
694 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue)
695 >= dev->tx_queue_len / tun->numqueues){
696 if (!(tun->flags & TUN_ONE_QUEUE)) {
697 /* Normal queueing mode. */
698 /* Packet scheduler handles dropping of further packets. */
699 netif_stop_subqueue(dev, txq);
701 /* We won't see all dropped packets individually, so overrun
702 * error is more appropriate. */
703 dev->stats.tx_fifo_errors++;
705 /* Single queue mode.
706 * Driver handles dropping of all packets itself. */
711 /* Orphan the skb - required as we might hang on to it
712 * for indefinite time. */
713 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
718 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
720 /* Notify and wake up reader process */
721 if (tfile->flags & TUN_FASYNC)
722 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
723 wake_up_interruptible_poll(&tfile->wq.wait, POLLIN |
724 POLLRDNORM | POLLRDBAND);
730 dev->stats.tx_dropped++;
737 static void tun_net_mclist(struct net_device *dev)
740 * This callback is supposed to deal with mc filter in
741 * _rx_ path and has nothing to do with the _tx_ path.
742 * In rx path we always accept everything userspace gives us.
747 #define MAX_MTU 65535
750 tun_net_change_mtu(struct net_device *dev, int new_mtu)
752 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
758 static netdev_features_t tun_net_fix_features(struct net_device *dev,
759 netdev_features_t features)
761 struct tun_struct *tun = netdev_priv(dev);
763 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
765 #ifdef CONFIG_NET_POLL_CONTROLLER
766 static void tun_poll_controller(struct net_device *dev)
769 * Tun only receives frames when:
770 * 1) the char device endpoint gets data from user space
771 * 2) the tun socket gets a sendmsg call from user space
772 * Since both of those are syncronous operations, we are guaranteed
773 * never to have pending data when we poll for it
774 * so theres nothing to do here but return.
775 * We need this though so netpoll recognizes us as an interface that
776 * supports polling, which enables bridge devices in virt setups to
777 * still use netconsole
782 static const struct net_device_ops tun_netdev_ops = {
783 .ndo_uninit = tun_net_uninit,
784 .ndo_open = tun_net_open,
785 .ndo_stop = tun_net_close,
786 .ndo_start_xmit = tun_net_xmit,
787 .ndo_change_mtu = tun_net_change_mtu,
788 .ndo_fix_features = tun_net_fix_features,
789 .ndo_select_queue = tun_select_queue,
790 #ifdef CONFIG_NET_POLL_CONTROLLER
791 .ndo_poll_controller = tun_poll_controller,
795 static const struct net_device_ops tap_netdev_ops = {
796 .ndo_uninit = tun_net_uninit,
797 .ndo_open = tun_net_open,
798 .ndo_stop = tun_net_close,
799 .ndo_start_xmit = tun_net_xmit,
800 .ndo_change_mtu = tun_net_change_mtu,
801 .ndo_fix_features = tun_net_fix_features,
802 .ndo_set_rx_mode = tun_net_mclist,
803 .ndo_set_mac_address = eth_mac_addr,
804 .ndo_validate_addr = eth_validate_addr,
805 .ndo_select_queue = tun_select_queue,
806 #ifdef CONFIG_NET_POLL_CONTROLLER
807 .ndo_poll_controller = tun_poll_controller,
811 static int tun_flow_init(struct tun_struct *tun)
815 tun->flow_cache = kmem_cache_create("tun_flow_cache",
816 sizeof(struct tun_flow_entry), 0, 0,
818 if (!tun->flow_cache)
821 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
822 INIT_HLIST_HEAD(&tun->flows[i]);
824 tun->ageing_time = TUN_FLOW_EXPIRE;
825 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
826 mod_timer(&tun->flow_gc_timer,
827 round_jiffies_up(jiffies + tun->ageing_time));
832 static void tun_flow_uninit(struct tun_struct *tun)
834 del_timer_sync(&tun->flow_gc_timer);
837 /* Wait for completion of call_rcu()'s */
839 kmem_cache_destroy(tun->flow_cache);
842 /* Initialize net device. */
843 static void tun_net_init(struct net_device *dev)
845 struct tun_struct *tun = netdev_priv(dev);
847 switch (tun->flags & TUN_TYPE_MASK) {
849 dev->netdev_ops = &tun_netdev_ops;
851 /* Point-to-Point TUN Device */
852 dev->hard_header_len = 0;
856 /* Zero header length */
857 dev->type = ARPHRD_NONE;
858 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
859 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
863 dev->netdev_ops = &tap_netdev_ops;
864 /* Ethernet TAP Device */
866 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
868 eth_hw_addr_random(dev);
870 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
875 /* Character device part */
878 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
880 struct tun_file *tfile = file->private_data;
881 struct tun_struct *tun = __tun_get(tfile);
883 unsigned int mask = 0;
888 sk = tfile->socket.sk;
890 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
892 poll_wait(file, &tfile->wq.wait, wait);
894 if (!skb_queue_empty(&sk->sk_receive_queue))
895 mask |= POLLIN | POLLRDNORM;
897 if (sock_writeable(sk) ||
898 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
900 mask |= POLLOUT | POLLWRNORM;
902 if (tun->dev->reg_state != NETREG_REGISTERED)
909 /* prepad is the amount to reserve at front. len is length after that.
910 * linear is a hint as to how much to copy (usually headers). */
911 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
912 size_t prepad, size_t len,
913 size_t linear, int noblock)
915 struct sock *sk = tfile->socket.sk;
919 /* Under a page? Don't bother with paged skb. */
920 if (prepad + len < PAGE_SIZE || !linear)
923 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
928 skb_reserve(skb, prepad);
929 skb_put(skb, linear);
930 skb->data_len = len - linear;
931 skb->len += len - linear;
936 /* set skb frags from iovec, this can move to core network code for reuse */
937 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
938 int offset, size_t count)
940 int len = iov_length(from, count) - offset;
941 int copy = skb_headlen(skb);
942 int size, offset1 = 0;
945 /* Skip over from offset */
946 while (count && (offset >= from->iov_len)) {
947 offset -= from->iov_len;
952 /* copy up to skb headlen */
953 while (count && (copy > 0)) {
954 size = min_t(unsigned int, copy, from->iov_len - offset);
955 if (copy_from_user(skb->data + offset1, from->iov_base + offset,
972 struct page *page[MAX_SKB_FRAGS];
975 unsigned long truesize;
977 len = from->iov_len - offset;
983 base = (unsigned long)from->iov_base + offset;
984 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
985 if (i + size > MAX_SKB_FRAGS)
987 num_pages = get_user_pages_fast(base, size, 0, &page[i]);
988 if (num_pages != size) {
989 for (i = 0; i < num_pages; i++)
993 truesize = size * PAGE_SIZE;
994 skb->data_len += len;
996 skb->truesize += truesize;
997 atomic_add(truesize, &skb->sk->sk_wmem_alloc);
999 int off = base & ~PAGE_MASK;
1000 int size = min_t(int, len, PAGE_SIZE - off);
1001 __skb_fill_page_desc(skb, i, page[i], off, size);
1002 skb_shinfo(skb)->nr_frags++;
1003 /* increase sk_wmem_alloc */
1014 /* Get packet from user space buffer */
1015 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1016 void *msg_control, const struct iovec *iv,
1017 size_t total_len, size_t count, int noblock)
1019 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1020 struct sk_buff *skb;
1021 size_t len = total_len, align = NET_SKB_PAD;
1022 struct virtio_net_hdr gso = { 0 };
1025 bool zerocopy = false;
1028 if (!(tun->flags & TUN_NO_PI)) {
1029 if ((len -= sizeof(pi)) > total_len)
1032 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
1034 offset += sizeof(pi);
1037 if (tun->flags & TUN_VNET_HDR) {
1038 if ((len -= tun->vnet_hdr_sz) > total_len)
1041 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
1044 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1045 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
1046 gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
1048 if (gso.hdr_len > len)
1050 offset += tun->vnet_hdr_sz;
1053 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
1054 align += NET_IP_ALIGN;
1055 if (unlikely(len < ETH_HLEN ||
1056 (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
1064 /* Userspace may produce vectors with count greater than
1065 * MAX_SKB_FRAGS, so we need to linearize parts of the skb
1066 * to let the rest of data to be fit in the frags.
1068 if (count > MAX_SKB_FRAGS) {
1069 copylen = iov_length(iv, count - MAX_SKB_FRAGS);
1070 if (copylen < offset)
1076 /* There are 256 bytes to be copied in skb, so there is enough
1077 * room for skb expand head in case it is used.
1078 * The rest of the buffer is mapped from userspace.
1080 if (copylen < gso.hdr_len)
1081 copylen = gso.hdr_len;
1083 copylen = GOODCOPY_LEN;
1087 skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, noblock);
1089 if (PTR_ERR(skb) != -EAGAIN)
1090 tun->dev->stats.rx_dropped++;
1091 return PTR_ERR(skb);
1095 err = zerocopy_sg_from_iovec(skb, iv, offset, count);
1097 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
1100 tun->dev->stats.rx_dropped++;
1105 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1106 if (!skb_partial_csum_set(skb, gso.csum_start,
1108 tun->dev->stats.rx_frame_errors++;
1114 switch (tun->flags & TUN_TYPE_MASK) {
1116 if (tun->flags & TUN_NO_PI) {
1117 switch (skb->data[0] & 0xf0) {
1119 pi.proto = htons(ETH_P_IP);
1122 pi.proto = htons(ETH_P_IPV6);
1125 tun->dev->stats.rx_dropped++;
1131 skb_reset_mac_header(skb);
1132 skb->protocol = pi.proto;
1133 skb->dev = tun->dev;
1136 skb->protocol = eth_type_trans(skb, tun->dev);
1140 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1142 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1143 case VIRTIO_NET_HDR_GSO_TCPV4:
1144 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1146 case VIRTIO_NET_HDR_GSO_TCPV6:
1147 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1149 case VIRTIO_NET_HDR_GSO_UDP:
1150 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1153 tun->dev->stats.rx_frame_errors++;
1158 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1159 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1161 skb_shinfo(skb)->gso_size = gso.gso_size;
1162 if (skb_shinfo(skb)->gso_size == 0) {
1163 tun->dev->stats.rx_frame_errors++;
1168 /* Header must be checked, and gso_segs computed. */
1169 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1170 skb_shinfo(skb)->gso_segs = 0;
1173 /* copy skb_ubuf_info for callback when skb has no error */
1175 skb_shinfo(skb)->destructor_arg = msg_control;
1176 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1181 tun->dev->stats.rx_packets++;
1182 tun->dev->stats.rx_bytes += len;
1184 tun_flow_update(tun, skb, tfile->queue_index);
1188 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
1189 unsigned long count, loff_t pos)
1191 struct file *file = iocb->ki_filp;
1192 struct tun_struct *tun = tun_get(file);
1193 struct tun_file *tfile = file->private_data;
1199 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
1201 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count),
1202 count, file->f_flags & O_NONBLOCK);
1208 /* Put packet to the user space buffer */
1209 static ssize_t tun_put_user(struct tun_struct *tun,
1210 struct tun_file *tfile,
1211 struct sk_buff *skb,
1212 const struct iovec *iv, int len)
1214 struct tun_pi pi = { 0, skb->protocol };
1217 if (!(tun->flags & TUN_NO_PI)) {
1218 if ((len -= sizeof(pi)) < 0)
1221 if (len < skb->len) {
1222 /* Packet will be striped */
1223 pi.flags |= TUN_PKT_STRIP;
1226 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
1228 total += sizeof(pi);
1231 if (tun->flags & TUN_VNET_HDR) {
1232 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1233 if ((len -= tun->vnet_hdr_sz) < 0)
1236 if (skb_is_gso(skb)) {
1237 struct skb_shared_info *sinfo = skb_shinfo(skb);
1239 /* This is a hint as to how much should be linear. */
1240 gso.hdr_len = skb_headlen(skb);
1241 gso.gso_size = sinfo->gso_size;
1242 if (sinfo->gso_type & SKB_GSO_TCPV4)
1243 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1244 else if (sinfo->gso_type & SKB_GSO_TCPV6)
1245 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1246 else if (sinfo->gso_type & SKB_GSO_UDP)
1247 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1249 pr_err("unexpected GSO type: "
1250 "0x%x, gso_size %d, hdr_len %d\n",
1251 sinfo->gso_type, gso.gso_size,
1253 print_hex_dump(KERN_ERR, "tun: ",
1256 min((int)gso.hdr_len, 64), true);
1260 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1261 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1263 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1265 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1266 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1267 gso.csum_start = skb_checksum_start_offset(skb);
1268 gso.csum_offset = skb->csum_offset;
1269 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1270 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1271 } /* else everything is zero */
1273 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
1276 total += tun->vnet_hdr_sz;
1279 len = min_t(int, skb->len, len);
1281 skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
1284 tun->dev->stats.tx_packets++;
1285 tun->dev->stats.tx_bytes += len;
1290 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1291 struct kiocb *iocb, const struct iovec *iv,
1292 ssize_t len, int noblock)
1294 DECLARE_WAITQUEUE(wait, current);
1295 struct sk_buff *skb;
1298 tun_debug(KERN_INFO, tun, "tun_chr_read\n");
1300 if (unlikely(!noblock))
1301 add_wait_queue(&tfile->wq.wait, &wait);
1303 current->state = TASK_INTERRUPTIBLE;
1305 /* Read frames from the queue */
1306 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) {
1311 if (signal_pending(current)) {
1315 if (tun->dev->reg_state != NETREG_REGISTERED) {
1320 /* Nothing to read, let's sleep */
1324 netif_wake_subqueue(tun->dev, tfile->queue_index);
1326 ret = tun_put_user(tun, tfile, skb, iv, len);
1331 current->state = TASK_RUNNING;
1332 if (unlikely(!noblock))
1333 remove_wait_queue(&tfile->wq.wait, &wait);
1338 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1339 unsigned long count, loff_t pos)
1341 struct file *file = iocb->ki_filp;
1342 struct tun_file *tfile = file->private_data;
1343 struct tun_struct *tun = __tun_get(tfile);
1348 len = iov_length(iv, count);
1354 ret = tun_do_read(tun, tfile, iocb, iv, len,
1355 file->f_flags & O_NONBLOCK);
1356 ret = min_t(ssize_t, ret, len);
1362 static void tun_free_netdev(struct net_device *dev)
1364 struct tun_struct *tun = netdev_priv(dev);
1366 tun_flow_uninit(tun);
1370 static void tun_setup(struct net_device *dev)
1372 struct tun_struct *tun = netdev_priv(dev);
1374 tun->owner = INVALID_UID;
1375 tun->group = INVALID_GID;
1377 dev->ethtool_ops = &tun_ethtool_ops;
1378 dev->destructor = tun_free_netdev;
1381 /* Trivial set of netlink ops to allow deleting tun or tap
1382 * device with netlink.
1384 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1389 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1391 .priv_size = sizeof(struct tun_struct),
1393 .validate = tun_validate,
1396 static void tun_sock_write_space(struct sock *sk)
1398 struct tun_file *tfile;
1399 wait_queue_head_t *wqueue;
1401 if (!sock_writeable(sk))
1404 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1407 wqueue = sk_sleep(sk);
1408 if (wqueue && waitqueue_active(wqueue))
1409 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1410 POLLWRNORM | POLLWRBAND);
1412 tfile = container_of(sk, struct tun_file, sk);
1413 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1416 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1417 struct msghdr *m, size_t total_len)
1420 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1421 struct tun_struct *tun = __tun_get(tfile);
1425 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len,
1426 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1432 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1433 struct msghdr *m, size_t total_len,
1436 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1437 struct tun_struct *tun = __tun_get(tfile);
1443 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1445 ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len,
1446 flags & MSG_DONTWAIT);
1447 if (ret > total_len) {
1448 m->msg_flags |= MSG_TRUNC;
1449 ret = flags & MSG_TRUNC ? ret : total_len;
1455 static int tun_release(struct socket *sock)
1462 /* Ops structure to mimic raw sockets with tun */
1463 static const struct proto_ops tun_socket_ops = {
1464 .sendmsg = tun_sendmsg,
1465 .recvmsg = tun_recvmsg,
1466 .release = tun_release,
1469 static struct proto tun_proto = {
1471 .owner = THIS_MODULE,
1472 .obj_size = sizeof(struct tun_file),
1475 static int tun_flags(struct tun_struct *tun)
1479 if (tun->flags & TUN_TUN_DEV)
1484 if (tun->flags & TUN_NO_PI)
1487 if (tun->flags & TUN_ONE_QUEUE)
1488 flags |= IFF_ONE_QUEUE;
1490 if (tun->flags & TUN_VNET_HDR)
1491 flags |= IFF_VNET_HDR;
1493 if (tun->flags & TUN_TAP_MQ)
1494 flags |= IFF_MULTI_QUEUE;
1499 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1502 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1503 return sprintf(buf, "0x%x\n", tun_flags(tun));
1506 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1509 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1510 return uid_valid(tun->owner)?
1511 sprintf(buf, "%u\n",
1512 from_kuid_munged(current_user_ns(), tun->owner)):
1513 sprintf(buf, "-1\n");
1516 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1519 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1520 return gid_valid(tun->group) ?
1521 sprintf(buf, "%u\n",
1522 from_kgid_munged(current_user_ns(), tun->group)):
1523 sprintf(buf, "-1\n");
1526 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1527 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1528 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1530 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1532 struct tun_struct *tun;
1533 struct tun_file *tfile = file->private_data;
1534 struct net_device *dev;
1537 dev = __dev_get_by_name(net, ifr->ifr_name);
1539 if (ifr->ifr_flags & IFF_TUN_EXCL)
1541 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1542 tun = netdev_priv(dev);
1543 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1544 tun = netdev_priv(dev);
1548 if (tun_not_capable(tun))
1550 err = security_tun_dev_attach(tfile->socket.sk);
1554 err = tun_attach(tun, file);
1560 unsigned long flags = 0;
1562 if (!capable(CAP_NET_ADMIN))
1564 err = security_tun_dev_create();
1569 if (ifr->ifr_flags & IFF_TUN) {
1571 flags |= TUN_TUN_DEV;
1573 } else if (ifr->ifr_flags & IFF_TAP) {
1575 flags |= TUN_TAP_DEV;
1581 name = ifr->ifr_name;
1583 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1585 MAX_TAP_QUEUES, MAX_TAP_QUEUES);
1589 dev_net_set(dev, net);
1590 dev->rtnl_link_ops = &tun_link_ops;
1592 tun = netdev_priv(dev);
1595 tun->txflt.count = 0;
1596 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1598 tun->filter_attached = false;
1599 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1601 spin_lock_init(&tun->lock);
1603 security_tun_dev_post_create(&tfile->sk);
1607 if (tun_flow_init(tun))
1610 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1612 dev->features = dev->hw_features;
1614 err = register_netdevice(tun->dev);
1618 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1619 device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1620 device_create_file(&tun->dev->dev, &dev_attr_group))
1621 pr_err("Failed to create tun sysfs files\n");
1623 err = tun_attach(tun, file);
1628 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1630 if (ifr->ifr_flags & IFF_NO_PI)
1631 tun->flags |= TUN_NO_PI;
1633 tun->flags &= ~TUN_NO_PI;
1635 if (ifr->ifr_flags & IFF_ONE_QUEUE)
1636 tun->flags |= TUN_ONE_QUEUE;
1638 tun->flags &= ~TUN_ONE_QUEUE;
1640 if (ifr->ifr_flags & IFF_VNET_HDR)
1641 tun->flags |= TUN_VNET_HDR;
1643 tun->flags &= ~TUN_VNET_HDR;
1645 if (ifr->ifr_flags & IFF_MULTI_QUEUE)
1646 tun->flags |= TUN_TAP_MQ;
1648 tun->flags &= ~TUN_TAP_MQ;
1650 /* Make sure persistent devices do not get stuck in
1653 if (netif_running(tun->dev))
1654 netif_tx_wake_all_queues(tun->dev);
1656 strcpy(ifr->ifr_name, tun->dev->name);
1664 static int tun_get_iff(struct net *net, struct tun_struct *tun,
1667 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1669 strcpy(ifr->ifr_name, tun->dev->name);
1671 ifr->ifr_flags = tun_flags(tun);
1676 /* This is like a cut-down ethtool ops, except done via tun fd so no
1677 * privs required. */
1678 static int set_offload(struct tun_struct *tun, unsigned long arg)
1680 netdev_features_t features = 0;
1682 if (arg & TUN_F_CSUM) {
1683 features |= NETIF_F_HW_CSUM;
1686 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1687 if (arg & TUN_F_TSO_ECN) {
1688 features |= NETIF_F_TSO_ECN;
1689 arg &= ~TUN_F_TSO_ECN;
1691 if (arg & TUN_F_TSO4)
1692 features |= NETIF_F_TSO;
1693 if (arg & TUN_F_TSO6)
1694 features |= NETIF_F_TSO6;
1695 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1698 if (arg & TUN_F_UFO) {
1699 features |= NETIF_F_UFO;
1704 /* This gives the user a way to test for new features in future by
1705 * trying to set them. */
1709 tun->set_features = features;
1710 netdev_update_features(tun->dev);
1715 static void tun_detach_filter(struct tun_struct *tun, int n)
1718 struct tun_file *tfile;
1720 for (i = 0; i < n; i++) {
1721 tfile = rcu_dereference_protected(tun->tfiles[i],
1722 lockdep_rtnl_is_held());
1723 sk_detach_filter(tfile->socket.sk);
1726 tun->filter_attached = false;
1729 static int tun_attach_filter(struct tun_struct *tun)
1732 struct tun_file *tfile;
1734 for (i = 0; i < tun->numqueues; i++) {
1735 tfile = rcu_dereference_protected(tun->tfiles[i],
1736 lockdep_rtnl_is_held());
1737 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1739 tun_detach_filter(tun, i);
1744 tun->filter_attached = true;
1748 static void tun_set_sndbuf(struct tun_struct *tun)
1750 struct tun_file *tfile;
1753 for (i = 0; i < tun->numqueues; i++) {
1754 tfile = rcu_dereference_protected(tun->tfiles[i],
1755 lockdep_rtnl_is_held());
1756 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1760 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1762 struct tun_file *tfile = file->private_data;
1763 struct tun_struct *tun;
1764 struct net_device *dev;
1769 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1770 dev = __dev_get_by_name(tfile->net, ifr->ifr_name);
1776 tun = netdev_priv(dev);
1777 if (dev->netdev_ops != &tap_netdev_ops &&
1778 dev->netdev_ops != &tun_netdev_ops)
1780 else if (tun_not_capable(tun))
1783 ret = tun_attach(tun, file);
1784 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE)
1785 __tun_detach(tfile, false);
1794 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1795 unsigned long arg, int ifreq_len)
1797 struct tun_file *tfile = file->private_data;
1798 struct tun_struct *tun;
1799 void __user* argp = (void __user*)arg;
1807 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1808 if (copy_from_user(&ifr, argp, ifreq_len))
1811 memset(&ifr, 0, sizeof(ifr));
1813 if (cmd == TUNGETFEATURES) {
1814 /* Currently this just means: "what IFF flags are valid?".
1815 * This is needed because we never checked for invalid flags on
1817 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1818 IFF_VNET_HDR | IFF_MULTI_QUEUE,
1819 (unsigned int __user*)argp);
1820 } else if (cmd == TUNSETQUEUE)
1821 return tun_set_queue(file, &ifr);
1826 tun = __tun_get(tfile);
1827 if (cmd == TUNSETIFF && !tun) {
1828 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1830 ret = tun_set_iff(tfile->net, file, &ifr);
1835 if (copy_to_user(argp, &ifr, ifreq_len))
1844 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1849 ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1853 if (copy_to_user(argp, &ifr, ifreq_len))
1858 /* Disable/Enable checksum */
1860 /* [unimplemented] */
1861 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1862 arg ? "disabled" : "enabled");
1866 /* Disable/Enable persist mode. Keep an extra reference to the
1867 * module to prevent the module being unprobed.
1870 tun->flags |= TUN_PERSIST;
1871 __module_get(THIS_MODULE);
1873 tun->flags &= ~TUN_PERSIST;
1874 module_put(THIS_MODULE);
1877 tun_debug(KERN_INFO, tun, "persist %s\n",
1878 arg ? "enabled" : "disabled");
1882 /* Set owner of the device */
1883 owner = make_kuid(current_user_ns(), arg);
1884 if (!uid_valid(owner)) {
1889 tun_debug(KERN_INFO, tun, "owner set to %u\n",
1890 from_kuid(&init_user_ns, tun->owner));
1894 /* Set group of the device */
1895 group = make_kgid(current_user_ns(), arg);
1896 if (!gid_valid(group)) {
1901 tun_debug(KERN_INFO, tun, "group set to %u\n",
1902 from_kgid(&init_user_ns, tun->group));
1906 /* Only allow setting the type when the interface is down */
1907 if (tun->dev->flags & IFF_UP) {
1908 tun_debug(KERN_INFO, tun,
1909 "Linktype set failed because interface is up\n");
1912 tun->dev->type = (int) arg;
1913 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1925 ret = set_offload(tun, arg);
1928 case TUNSETTXFILTER:
1929 /* Can be set only for TAPs */
1931 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1933 ret = update_filter(&tun->txflt, (void __user *)arg);
1937 /* Get hw address */
1938 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1939 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1940 if (copy_to_user(argp, &ifr, ifreq_len))
1945 /* Set hw address */
1946 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1947 ifr.ifr_hwaddr.sa_data);
1949 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1953 sndbuf = tfile->socket.sk->sk_sndbuf;
1954 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1959 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1964 tun->sndbuf = sndbuf;
1965 tun_set_sndbuf(tun);
1968 case TUNGETVNETHDRSZ:
1969 vnet_hdr_sz = tun->vnet_hdr_sz;
1970 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
1974 case TUNSETVNETHDRSZ:
1975 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
1979 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
1984 tun->vnet_hdr_sz = vnet_hdr_sz;
1987 case TUNATTACHFILTER:
1988 /* Can be set only for TAPs */
1990 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1993 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
1996 ret = tun_attach_filter(tun);
1999 case TUNDETACHFILTER:
2000 /* Can be set only for TAPs */
2002 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2005 tun_detach_filter(tun, tun->numqueues);
2020 static long tun_chr_ioctl(struct file *file,
2021 unsigned int cmd, unsigned long arg)
2023 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2026 #ifdef CONFIG_COMPAT
2027 static long tun_chr_compat_ioctl(struct file *file,
2028 unsigned int cmd, unsigned long arg)
2033 case TUNSETTXFILTER:
2038 arg = (unsigned long)compat_ptr(arg);
2041 arg = (compat_ulong_t)arg;
2046 * compat_ifreq is shorter than ifreq, so we must not access beyond
2047 * the end of that structure. All fields that are used in this
2048 * driver are compatible though, we don't need to convert the
2051 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2053 #endif /* CONFIG_COMPAT */
2055 static int tun_chr_fasync(int fd, struct file *file, int on)
2057 struct tun_file *tfile = file->private_data;
2060 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2064 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2067 tfile->flags |= TUN_FASYNC;
2069 tfile->flags &= ~TUN_FASYNC;
2075 static int tun_chr_open(struct inode *inode, struct file * file)
2077 struct tun_file *tfile;
2079 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2081 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
2085 rcu_assign_pointer(tfile->tun, NULL);
2086 tfile->net = get_net(current->nsproxy->net_ns);
2089 rcu_assign_pointer(tfile->socket.wq, &tfile->wq);
2090 init_waitqueue_head(&tfile->wq.wait);
2092 tfile->socket.file = file;
2093 tfile->socket.ops = &tun_socket_ops;
2095 sock_init_data(&tfile->socket, &tfile->sk);
2096 sk_change_net(&tfile->sk, tfile->net);
2098 tfile->sk.sk_write_space = tun_sock_write_space;
2099 tfile->sk.sk_sndbuf = INT_MAX;
2101 file->private_data = tfile;
2102 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
2107 static int tun_chr_close(struct inode *inode, struct file *file)
2109 struct tun_file *tfile = file->private_data;
2110 struct net *net = tfile->net;
2112 tun_detach(tfile, true);
2118 static const struct file_operations tun_fops = {
2119 .owner = THIS_MODULE,
2120 .llseek = no_llseek,
2121 .read = do_sync_read,
2122 .aio_read = tun_chr_aio_read,
2123 .write = do_sync_write,
2124 .aio_write = tun_chr_aio_write,
2125 .poll = tun_chr_poll,
2126 .unlocked_ioctl = tun_chr_ioctl,
2127 #ifdef CONFIG_COMPAT
2128 .compat_ioctl = tun_chr_compat_ioctl,
2130 .open = tun_chr_open,
2131 .release = tun_chr_close,
2132 .fasync = tun_chr_fasync
2135 static struct miscdevice tun_miscdev = {
2138 .nodename = "net/tun",
2142 /* ethtool interface */
2144 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2147 cmd->advertising = 0;
2148 ethtool_cmd_speed_set(cmd, SPEED_10);
2149 cmd->duplex = DUPLEX_FULL;
2150 cmd->port = PORT_TP;
2151 cmd->phy_address = 0;
2152 cmd->transceiver = XCVR_INTERNAL;
2153 cmd->autoneg = AUTONEG_DISABLE;
2159 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2161 struct tun_struct *tun = netdev_priv(dev);
2163 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2164 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2166 switch (tun->flags & TUN_TYPE_MASK) {
2168 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2171 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2176 static u32 tun_get_msglevel(struct net_device *dev)
2179 struct tun_struct *tun = netdev_priv(dev);
2186 static void tun_set_msglevel(struct net_device *dev, u32 value)
2189 struct tun_struct *tun = netdev_priv(dev);
2194 static const struct ethtool_ops tun_ethtool_ops = {
2195 .get_settings = tun_get_settings,
2196 .get_drvinfo = tun_get_drvinfo,
2197 .get_msglevel = tun_get_msglevel,
2198 .set_msglevel = tun_set_msglevel,
2199 .get_link = ethtool_op_get_link,
2203 static int __init tun_init(void)
2207 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2208 pr_info("%s\n", DRV_COPYRIGHT);
2210 ret = rtnl_link_register(&tun_link_ops);
2212 pr_err("Can't register link_ops\n");
2216 ret = misc_register(&tun_miscdev);
2218 pr_err("Can't register misc device %d\n", TUN_MINOR);
2223 rtnl_link_unregister(&tun_link_ops);
2228 static void tun_cleanup(void)
2230 misc_deregister(&tun_miscdev);
2231 rtnl_link_unregister(&tun_link_ops);
2234 /* Get an underlying socket object from tun file. Returns error unless file is
2235 * attached to a device. The returned object works like a packet socket, it
2236 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
2237 * holding a reference to the file for as long as the socket is in use. */
2238 struct socket *tun_get_socket(struct file *file)
2240 struct tun_file *tfile;
2241 if (file->f_op != &tun_fops)
2242 return ERR_PTR(-EINVAL);
2243 tfile = file->private_data;
2245 return ERR_PTR(-EBADFD);
2246 return &tfile->socket;
2248 EXPORT_SYMBOL_GPL(tun_get_socket);
2250 module_init(tun_init);
2251 module_exit(tun_cleanup);
2252 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2253 MODULE_AUTHOR(DRV_COPYRIGHT);
2254 MODULE_LICENSE("GPL");
2255 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2256 MODULE_ALIAS("devname:net/tun");