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Linux/drivers/net/tun.c

  1 /*
  2  *  TUN - Universal TUN/TAP device driver.
  3  *  Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
  4  *
  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.
  9  *
 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.
 14  *
 15  *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
 16  */
 17 
 18 /*
 19  *  Changes:
 20  *
 21  *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
 22  *    Add TUNSETLINK ioctl to set the link encapsulation
 23  *
 24  *  Mark Smith <markzzzsmith@yahoo.com.au>
 25  *    Use eth_random_addr() for tap MAC address.
 26  *
 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.
 30  *    Added ethtool API.
 31  *    Minor cleanups
 32  *
 33  *  Daniel Podlejski <underley@underley.eu.org>
 34  *    Modifications for 2.3.99-pre5 kernel.
 35  */
 36 
 37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 38 
 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>"
 43 
 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>
 59 #include <linux/if.h>
 60 #include <linux/if_arp.h>
 61 #include <linux/if_ether.h>
 62 #include <linux/if_tun.h>
 63 #include <linux/if_vlan.h>
 64 #include <linux/crc32.h>
 65 #include <linux/nsproxy.h>
 66 #include <linux/virtio_net.h>
 67 #include <linux/rcupdate.h>
 68 #include <net/net_namespace.h>
 69 #include <net/netns/generic.h>
 70 #include <net/rtnetlink.h>
 71 #include <net/sock.h>
 72 #include <linux/seq_file.h>
 73 #include <linux/uio.h>
 74 
 75 #include <asm/uaccess.h>
 76 
 77 /* Uncomment to enable debugging */
 78 /* #define TUN_DEBUG 1 */
 79 
 80 #ifdef TUN_DEBUG
 81 static int debug;
 82 
 83 #define tun_debug(level, tun, fmt, args...)                     \
 84 do {                                                            \
 85         if (tun->debug)                                         \
 86                 netdev_printk(level, tun->dev, fmt, ##args);    \
 87 } while (0)
 88 #define DBG1(level, fmt, args...)                               \
 89 do {                                                            \
 90         if (debug == 2)                                         \
 91                 printk(level fmt, ##args);                      \
 92 } while (0)
 93 #else
 94 #define tun_debug(level, tun, fmt, args...)                     \
 95 do {                                                            \
 96         if (0)                                                  \
 97                 netdev_printk(level, tun->dev, fmt, ##args);    \
 98 } while (0)
 99 #define DBG1(level, fmt, args...)                               \
100 do {                                                            \
101         if (0)                                                  \
102                 printk(level fmt, ##args);                      \
103 } while (0)
104 #endif
105 
106 /* TUN device flags */
107 
108 /* IFF_ATTACH_QUEUE is never stored in device flags,
109  * overload it to mean fasync when stored there.
110  */
111 #define TUN_FASYNC      IFF_ATTACH_QUEUE
112 /* High bits in flags field are unused. */
113 #define TUN_VNET_LE     0x80000000
114 
115 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
116                       IFF_MULTI_QUEUE)
117 #define GOODCOPY_LEN 128
118 
119 #define FLT_EXACT_COUNT 8
120 struct tap_filter {
121         unsigned int    count;    /* Number of addrs. Zero means disabled */
122         u32             mask[2];  /* Mask of the hashed addrs */
123         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
124 };
125 
126 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
127  * to max number of VCPUs in guest. */
128 #define MAX_TAP_QUEUES 256
129 #define MAX_TAP_FLOWS  4096
130 
131 #define TUN_FLOW_EXPIRE (3 * HZ)
132 
133 /* A tun_file connects an open character device to a tuntap netdevice. It
134  * also contains all socket related structures (except sock_fprog and tap_filter)
135  * to serve as one transmit queue for tuntap device. The sock_fprog and
136  * tap_filter were kept in tun_struct since they were used for filtering for the
137  * netdevice not for a specific queue (at least I didn't see the requirement for
138  * this).
139  *
140  * RCU usage:
141  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
142  * other can only be read while rcu_read_lock or rtnl_lock is held.
143  */
144 struct tun_file {
145         struct sock sk;
146         struct socket socket;
147         struct socket_wq wq;
148         struct tun_struct __rcu *tun;
149         struct net *net;
150         struct fasync_struct *fasync;
151         /* only used for fasnyc */
152         unsigned int flags;
153         union {
154                 u16 queue_index;
155                 unsigned int ifindex;
156         };
157         struct list_head next;
158         struct tun_struct *detached;
159 };
160 
161 struct tun_flow_entry {
162         struct hlist_node hash_link;
163         struct rcu_head rcu;
164         struct tun_struct *tun;
165 
166         u32 rxhash;
167         u32 rps_rxhash;
168         int queue_index;
169         unsigned long updated;
170 };
171 
172 #define TUN_NUM_FLOW_ENTRIES 1024
173 
174 /* Since the socket were moved to tun_file, to preserve the behavior of persist
175  * device, socket filter, sndbuf and vnet header size were restore when the
176  * file were attached to a persist device.
177  */
178 struct tun_struct {
179         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
180         unsigned int            numqueues;
181         unsigned int            flags;
182         kuid_t                  owner;
183         kgid_t                  group;
184 
185         struct net_device       *dev;
186         netdev_features_t       set_features;
187 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
188                           NETIF_F_TSO6|NETIF_F_UFO)
189 
190         int                     vnet_hdr_sz;
191         int                     sndbuf;
192         struct tap_filter       txflt;
193         struct sock_fprog       fprog;
194         /* protected by rtnl lock */
195         bool                    filter_attached;
196 #ifdef TUN_DEBUG
197         int debug;
198 #endif
199         spinlock_t lock;
200         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
201         struct timer_list flow_gc_timer;
202         unsigned long ageing_time;
203         unsigned int numdisabled;
204         struct list_head disabled;
205         void *security;
206         u32 flow_count;
207 };
208 
209 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
210 {
211         return __virtio16_to_cpu(tun->flags & TUN_VNET_LE, val);
212 }
213 
214 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
215 {
216         return __cpu_to_virtio16(tun->flags & TUN_VNET_LE, val);
217 }
218 
219 static inline u32 tun_hashfn(u32 rxhash)
220 {
221         return rxhash & 0x3ff;
222 }
223 
224 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
225 {
226         struct tun_flow_entry *e;
227 
228         hlist_for_each_entry_rcu(e, head, hash_link) {
229                 if (e->rxhash == rxhash)
230                         return e;
231         }
232         return NULL;
233 }
234 
235 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
236                                               struct hlist_head *head,
237                                               u32 rxhash, u16 queue_index)
238 {
239         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
240 
241         if (e) {
242                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
243                           rxhash, queue_index);
244                 e->updated = jiffies;
245                 e->rxhash = rxhash;
246                 e->rps_rxhash = 0;
247                 e->queue_index = queue_index;
248                 e->tun = tun;
249                 hlist_add_head_rcu(&e->hash_link, head);
250                 ++tun->flow_count;
251         }
252         return e;
253 }
254 
255 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
256 {
257         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
258                   e->rxhash, e->queue_index);
259         hlist_del_rcu(&e->hash_link);
260         kfree_rcu(e, rcu);
261         --tun->flow_count;
262 }
263 
264 static void tun_flow_flush(struct tun_struct *tun)
265 {
266         int i;
267 
268         spin_lock_bh(&tun->lock);
269         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
270                 struct tun_flow_entry *e;
271                 struct hlist_node *n;
272 
273                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
274                         tun_flow_delete(tun, e);
275         }
276         spin_unlock_bh(&tun->lock);
277 }
278 
279 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
280 {
281         int i;
282 
283         spin_lock_bh(&tun->lock);
284         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
285                 struct tun_flow_entry *e;
286                 struct hlist_node *n;
287 
288                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
289                         if (e->queue_index == queue_index)
290                                 tun_flow_delete(tun, e);
291                 }
292         }
293         spin_unlock_bh(&tun->lock);
294 }
295 
296 static void tun_flow_cleanup(unsigned long data)
297 {
298         struct tun_struct *tun = (struct tun_struct *)data;
299         unsigned long delay = tun->ageing_time;
300         unsigned long next_timer = jiffies + delay;
301         unsigned long count = 0;
302         int i;
303 
304         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
305 
306         spin_lock_bh(&tun->lock);
307         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
308                 struct tun_flow_entry *e;
309                 struct hlist_node *n;
310 
311                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
312                         unsigned long this_timer;
313                         count++;
314                         this_timer = e->updated + delay;
315                         if (time_before_eq(this_timer, jiffies))
316                                 tun_flow_delete(tun, e);
317                         else if (time_before(this_timer, next_timer))
318                                 next_timer = this_timer;
319                 }
320         }
321 
322         if (count)
323                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
324         spin_unlock_bh(&tun->lock);
325 }
326 
327 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
328                             struct tun_file *tfile)
329 {
330         struct hlist_head *head;
331         struct tun_flow_entry *e;
332         unsigned long delay = tun->ageing_time;
333         u16 queue_index = tfile->queue_index;
334 
335         if (!rxhash)
336                 return;
337         else
338                 head = &tun->flows[tun_hashfn(rxhash)];
339 
340         rcu_read_lock();
341 
342         /* We may get a very small possibility of OOO during switching, not
343          * worth to optimize.*/
344         if (tun->numqueues == 1 || tfile->detached)
345                 goto unlock;
346 
347         e = tun_flow_find(head, rxhash);
348         if (likely(e)) {
349                 /* TODO: keep queueing to old queue until it's empty? */
350                 e->queue_index = queue_index;
351                 e->updated = jiffies;
352                 sock_rps_record_flow_hash(e->rps_rxhash);
353         } else {
354                 spin_lock_bh(&tun->lock);
355                 if (!tun_flow_find(head, rxhash) &&
356                     tun->flow_count < MAX_TAP_FLOWS)
357                         tun_flow_create(tun, head, rxhash, queue_index);
358 
359                 if (!timer_pending(&tun->flow_gc_timer))
360                         mod_timer(&tun->flow_gc_timer,
361                                   round_jiffies_up(jiffies + delay));
362                 spin_unlock_bh(&tun->lock);
363         }
364 
365 unlock:
366         rcu_read_unlock();
367 }
368 
369 /**
370  * Save the hash received in the stack receive path and update the
371  * flow_hash table accordingly.
372  */
373 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
374 {
375         if (unlikely(e->rps_rxhash != hash))
376                 e->rps_rxhash = hash;
377 }
378 
379 /* We try to identify a flow through its rxhash first. The reason that
380  * we do not check rxq no. is because some cards(e.g 82599), chooses
381  * the rxq based on the txq where the last packet of the flow comes. As
382  * the userspace application move between processors, we may get a
383  * different rxq no. here. If we could not get rxhash, then we would
384  * hope the rxq no. may help here.
385  */
386 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
387                             void *accel_priv, select_queue_fallback_t fallback)
388 {
389         struct tun_struct *tun = netdev_priv(dev);
390         struct tun_flow_entry *e;
391         u32 txq = 0;
392         u32 numqueues = 0;
393 
394         rcu_read_lock();
395         numqueues = ACCESS_ONCE(tun->numqueues);
396 
397         txq = skb_get_hash(skb);
398         if (txq) {
399                 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
400                 if (e) {
401                         tun_flow_save_rps_rxhash(e, txq);
402                         txq = e->queue_index;
403                 } else
404                         /* use multiply and shift instead of expensive divide */
405                         txq = ((u64)txq * numqueues) >> 32;
406         } else if (likely(skb_rx_queue_recorded(skb))) {
407                 txq = skb_get_rx_queue(skb);
408                 while (unlikely(txq >= numqueues))
409                         txq -= numqueues;
410         }
411 
412         rcu_read_unlock();
413         return txq;
414 }
415 
416 static inline bool tun_not_capable(struct tun_struct *tun)
417 {
418         const struct cred *cred = current_cred();
419         struct net *net = dev_net(tun->dev);
420 
421         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
422                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
423                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
424 }
425 
426 static void tun_set_real_num_queues(struct tun_struct *tun)
427 {
428         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
429         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
430 }
431 
432 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
433 {
434         tfile->detached = tun;
435         list_add_tail(&tfile->next, &tun->disabled);
436         ++tun->numdisabled;
437 }
438 
439 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
440 {
441         struct tun_struct *tun = tfile->detached;
442 
443         tfile->detached = NULL;
444         list_del_init(&tfile->next);
445         --tun->numdisabled;
446         return tun;
447 }
448 
449 static void tun_queue_purge(struct tun_file *tfile)
450 {
451         skb_queue_purge(&tfile->sk.sk_receive_queue);
452         skb_queue_purge(&tfile->sk.sk_error_queue);
453 }
454 
455 static void __tun_detach(struct tun_file *tfile, bool clean)
456 {
457         struct tun_file *ntfile;
458         struct tun_struct *tun;
459 
460         tun = rtnl_dereference(tfile->tun);
461 
462         if (tun && !tfile->detached) {
463                 u16 index = tfile->queue_index;
464                 BUG_ON(index >= tun->numqueues);
465 
466                 rcu_assign_pointer(tun->tfiles[index],
467                                    tun->tfiles[tun->numqueues - 1]);
468                 ntfile = rtnl_dereference(tun->tfiles[index]);
469                 ntfile->queue_index = index;
470 
471                 --tun->numqueues;
472                 if (clean) {
473                         RCU_INIT_POINTER(tfile->tun, NULL);
474                         sock_put(&tfile->sk);
475                 } else
476                         tun_disable_queue(tun, tfile);
477 
478                 synchronize_net();
479                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
480                 /* Drop read queue */
481                 tun_queue_purge(tfile);
482                 tun_set_real_num_queues(tun);
483         } else if (tfile->detached && clean) {
484                 tun = tun_enable_queue(tfile);
485                 sock_put(&tfile->sk);
486         }
487 
488         if (clean) {
489                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
490                         netif_carrier_off(tun->dev);
491 
492                         if (!(tun->flags & IFF_PERSIST) &&
493                             tun->dev->reg_state == NETREG_REGISTERED)
494                                 unregister_netdevice(tun->dev);
495                 }
496 
497                 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
498                                  &tfile->socket.flags));
499                 sk_release_kernel(&tfile->sk);
500         }
501 }
502 
503 static void tun_detach(struct tun_file *tfile, bool clean)
504 {
505         rtnl_lock();
506         __tun_detach(tfile, clean);
507         rtnl_unlock();
508 }
509 
510 static void tun_detach_all(struct net_device *dev)
511 {
512         struct tun_struct *tun = netdev_priv(dev);
513         struct tun_file *tfile, *tmp;
514         int i, n = tun->numqueues;
515 
516         for (i = 0; i < n; i++) {
517                 tfile = rtnl_dereference(tun->tfiles[i]);
518                 BUG_ON(!tfile);
519                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
520                 RCU_INIT_POINTER(tfile->tun, NULL);
521                 --tun->numqueues;
522         }
523         list_for_each_entry(tfile, &tun->disabled, next) {
524                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
525                 RCU_INIT_POINTER(tfile->tun, NULL);
526         }
527         BUG_ON(tun->numqueues != 0);
528 
529         synchronize_net();
530         for (i = 0; i < n; i++) {
531                 tfile = rtnl_dereference(tun->tfiles[i]);
532                 /* Drop read queue */
533                 tun_queue_purge(tfile);
534                 sock_put(&tfile->sk);
535         }
536         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
537                 tun_enable_queue(tfile);
538                 tun_queue_purge(tfile);
539                 sock_put(&tfile->sk);
540         }
541         BUG_ON(tun->numdisabled != 0);
542 
543         if (tun->flags & IFF_PERSIST)
544                 module_put(THIS_MODULE);
545 }
546 
547 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
548 {
549         struct tun_file *tfile = file->private_data;
550         int err;
551 
552         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
553         if (err < 0)
554                 goto out;
555 
556         err = -EINVAL;
557         if (rtnl_dereference(tfile->tun) && !tfile->detached)
558                 goto out;
559 
560         err = -EBUSY;
561         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
562                 goto out;
563 
564         err = -E2BIG;
565         if (!tfile->detached &&
566             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
567                 goto out;
568 
569         err = 0;
570 
571         /* Re-attach the filter to persist device */
572         if (!skip_filter && (tun->filter_attached == true)) {
573                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
574                 if (!err)
575                         goto out;
576         }
577         tfile->queue_index = tun->numqueues;
578         rcu_assign_pointer(tfile->tun, tun);
579         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
580         tun->numqueues++;
581 
582         if (tfile->detached)
583                 tun_enable_queue(tfile);
584         else
585                 sock_hold(&tfile->sk);
586 
587         tun_set_real_num_queues(tun);
588 
589         /* device is allowed to go away first, so no need to hold extra
590          * refcnt.
591          */
592 
593 out:
594         return err;
595 }
596 
597 static struct tun_struct *__tun_get(struct tun_file *tfile)
598 {
599         struct tun_struct *tun;
600 
601         rcu_read_lock();
602         tun = rcu_dereference(tfile->tun);
603         if (tun)
604                 dev_hold(tun->dev);
605         rcu_read_unlock();
606 
607         return tun;
608 }
609 
610 static struct tun_struct *tun_get(struct file *file)
611 {
612         return __tun_get(file->private_data);
613 }
614 
615 static void tun_put(struct tun_struct *tun)
616 {
617         dev_put(tun->dev);
618 }
619 
620 /* TAP filtering */
621 static void addr_hash_set(u32 *mask, const u8 *addr)
622 {
623         int n = ether_crc(ETH_ALEN, addr) >> 26;
624         mask[n >> 5] |= (1 << (n & 31));
625 }
626 
627 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
628 {
629         int n = ether_crc(ETH_ALEN, addr) >> 26;
630         return mask[n >> 5] & (1 << (n & 31));
631 }
632 
633 static int update_filter(struct tap_filter *filter, void __user *arg)
634 {
635         struct { u8 u[ETH_ALEN]; } *addr;
636         struct tun_filter uf;
637         int err, alen, n, nexact;
638 
639         if (copy_from_user(&uf, arg, sizeof(uf)))
640                 return -EFAULT;
641 
642         if (!uf.count) {
643                 /* Disabled */
644                 filter->count = 0;
645                 return 0;
646         }
647 
648         alen = ETH_ALEN * uf.count;
649         addr = kmalloc(alen, GFP_KERNEL);
650         if (!addr)
651                 return -ENOMEM;
652 
653         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
654                 err = -EFAULT;
655                 goto done;
656         }
657 
658         /* The filter is updated without holding any locks. Which is
659          * perfectly safe. We disable it first and in the worst
660          * case we'll accept a few undesired packets. */
661         filter->count = 0;
662         wmb();
663 
664         /* Use first set of addresses as an exact filter */
665         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
666                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
667 
668         nexact = n;
669 
670         /* Remaining multicast addresses are hashed,
671          * unicast will leave the filter disabled. */
672         memset(filter->mask, 0, sizeof(filter->mask));
673         for (; n < uf.count; n++) {
674                 if (!is_multicast_ether_addr(addr[n].u)) {
675                         err = 0; /* no filter */
676                         goto done;
677                 }
678                 addr_hash_set(filter->mask, addr[n].u);
679         }
680 
681         /* For ALLMULTI just set the mask to all ones.
682          * This overrides the mask populated above. */
683         if ((uf.flags & TUN_FLT_ALLMULTI))
684                 memset(filter->mask, ~0, sizeof(filter->mask));
685 
686         /* Now enable the filter */
687         wmb();
688         filter->count = nexact;
689 
690         /* Return the number of exact filters */
691         err = nexact;
692 
693 done:
694         kfree(addr);
695         return err;
696 }
697 
698 /* Returns: 0 - drop, !=0 - accept */
699 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
700 {
701         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
702          * at this point. */
703         struct ethhdr *eh = (struct ethhdr *) skb->data;
704         int i;
705 
706         /* Exact match */
707         for (i = 0; i < filter->count; i++)
708                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
709                         return 1;
710 
711         /* Inexact match (multicast only) */
712         if (is_multicast_ether_addr(eh->h_dest))
713                 return addr_hash_test(filter->mask, eh->h_dest);
714 
715         return 0;
716 }
717 
718 /*
719  * Checks whether the packet is accepted or not.
720  * Returns: 0 - drop, !=0 - accept
721  */
722 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
723 {
724         if (!filter->count)
725                 return 1;
726 
727         return run_filter(filter, skb);
728 }
729 
730 /* Network device part of the driver */
731 
732 static const struct ethtool_ops tun_ethtool_ops;
733 
734 /* Net device detach from fd. */
735 static void tun_net_uninit(struct net_device *dev)
736 {
737         tun_detach_all(dev);
738 }
739 
740 /* Net device open. */
741 static int tun_net_open(struct net_device *dev)
742 {
743         netif_tx_start_all_queues(dev);
744         return 0;
745 }
746 
747 /* Net device close. */
748 static int tun_net_close(struct net_device *dev)
749 {
750         netif_tx_stop_all_queues(dev);
751         return 0;
752 }
753 
754 /* Net device start xmit */
755 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
756 {
757         struct tun_struct *tun = netdev_priv(dev);
758         int txq = skb->queue_mapping;
759         struct tun_file *tfile;
760         u32 numqueues = 0;
761 
762         rcu_read_lock();
763         tfile = rcu_dereference(tun->tfiles[txq]);
764         numqueues = ACCESS_ONCE(tun->numqueues);
765 
766         /* Drop packet if interface is not attached */
767         if (txq >= numqueues)
768                 goto drop;
769 
770         if (numqueues == 1) {
771                 /* Select queue was not called for the skbuff, so we extract the
772                  * RPS hash and save it into the flow_table here.
773                  */
774                 __u32 rxhash;
775 
776                 rxhash = skb_get_hash(skb);
777                 if (rxhash) {
778                         struct tun_flow_entry *e;
779                         e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
780                                         rxhash);
781                         if (e)
782                                 tun_flow_save_rps_rxhash(e, rxhash);
783                 }
784         }
785 
786         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
787 
788         BUG_ON(!tfile);
789 
790         /* Drop if the filter does not like it.
791          * This is a noop if the filter is disabled.
792          * Filter can be enabled only for the TAP devices. */
793         if (!check_filter(&tun->txflt, skb))
794                 goto drop;
795 
796         if (tfile->socket.sk->sk_filter &&
797             sk_filter(tfile->socket.sk, skb))
798                 goto drop;
799 
800         /* Limit the number of packets queued by dividing txq length with the
801          * number of queues.
802          */
803         if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues
804                           >= dev->tx_queue_len)
805                 goto drop;
806 
807         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
808                 goto drop;
809 
810         if (skb->sk) {
811                 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags);
812                 sw_tx_timestamp(skb);
813         }
814 
815         /* Orphan the skb - required as we might hang on to it
816          * for indefinite time.
817          */
818         skb_orphan(skb);
819 
820         nf_reset(skb);
821 
822         /* Enqueue packet */
823         skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
824 
825         /* Notify and wake up reader process */
826         if (tfile->flags & TUN_FASYNC)
827                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
828         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
829 
830         rcu_read_unlock();
831         return NETDEV_TX_OK;
832 
833 drop:
834         dev->stats.tx_dropped++;
835         skb_tx_error(skb);
836         kfree_skb(skb);
837         rcu_read_unlock();
838         return NET_XMIT_DROP;
839 }
840 
841 static void tun_net_mclist(struct net_device *dev)
842 {
843         /*
844          * This callback is supposed to deal with mc filter in
845          * _rx_ path and has nothing to do with the _tx_ path.
846          * In rx path we always accept everything userspace gives us.
847          */
848 }
849 
850 #define MIN_MTU 68
851 #define MAX_MTU 65535
852 
853 static int
854 tun_net_change_mtu(struct net_device *dev, int new_mtu)
855 {
856         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
857                 return -EINVAL;
858         dev->mtu = new_mtu;
859         return 0;
860 }
861 
862 static netdev_features_t tun_net_fix_features(struct net_device *dev,
863         netdev_features_t features)
864 {
865         struct tun_struct *tun = netdev_priv(dev);
866 
867         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
868 }
869 #ifdef CONFIG_NET_POLL_CONTROLLER
870 static void tun_poll_controller(struct net_device *dev)
871 {
872         /*
873          * Tun only receives frames when:
874          * 1) the char device endpoint gets data from user space
875          * 2) the tun socket gets a sendmsg call from user space
876          * Since both of those are synchronous operations, we are guaranteed
877          * never to have pending data when we poll for it
878          * so there is nothing to do here but return.
879          * We need this though so netpoll recognizes us as an interface that
880          * supports polling, which enables bridge devices in virt setups to
881          * still use netconsole
882          */
883         return;
884 }
885 #endif
886 static const struct net_device_ops tun_netdev_ops = {
887         .ndo_uninit             = tun_net_uninit,
888         .ndo_open               = tun_net_open,
889         .ndo_stop               = tun_net_close,
890         .ndo_start_xmit         = tun_net_xmit,
891         .ndo_change_mtu         = tun_net_change_mtu,
892         .ndo_fix_features       = tun_net_fix_features,
893         .ndo_select_queue       = tun_select_queue,
894 #ifdef CONFIG_NET_POLL_CONTROLLER
895         .ndo_poll_controller    = tun_poll_controller,
896 #endif
897 };
898 
899 static const struct net_device_ops tap_netdev_ops = {
900         .ndo_uninit             = tun_net_uninit,
901         .ndo_open               = tun_net_open,
902         .ndo_stop               = tun_net_close,
903         .ndo_start_xmit         = tun_net_xmit,
904         .ndo_change_mtu         = tun_net_change_mtu,
905         .ndo_fix_features       = tun_net_fix_features,
906         .ndo_set_rx_mode        = tun_net_mclist,
907         .ndo_set_mac_address    = eth_mac_addr,
908         .ndo_validate_addr      = eth_validate_addr,
909         .ndo_select_queue       = tun_select_queue,
910 #ifdef CONFIG_NET_POLL_CONTROLLER
911         .ndo_poll_controller    = tun_poll_controller,
912 #endif
913 };
914 
915 static void tun_flow_init(struct tun_struct *tun)
916 {
917         int i;
918 
919         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
920                 INIT_HLIST_HEAD(&tun->flows[i]);
921 
922         tun->ageing_time = TUN_FLOW_EXPIRE;
923         setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
924         mod_timer(&tun->flow_gc_timer,
925                   round_jiffies_up(jiffies + tun->ageing_time));
926 }
927 
928 static void tun_flow_uninit(struct tun_struct *tun)
929 {
930         del_timer_sync(&tun->flow_gc_timer);
931         tun_flow_flush(tun);
932 }
933 
934 /* Initialize net device. */
935 static void tun_net_init(struct net_device *dev)
936 {
937         struct tun_struct *tun = netdev_priv(dev);
938 
939         switch (tun->flags & TUN_TYPE_MASK) {
940         case IFF_TUN:
941                 dev->netdev_ops = &tun_netdev_ops;
942 
943                 /* Point-to-Point TUN Device */
944                 dev->hard_header_len = 0;
945                 dev->addr_len = 0;
946                 dev->mtu = 1500;
947 
948                 /* Zero header length */
949                 dev->type = ARPHRD_NONE;
950                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
951                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
952                 break;
953 
954         case IFF_TAP:
955                 dev->netdev_ops = &tap_netdev_ops;
956                 /* Ethernet TAP Device */
957                 ether_setup(dev);
958                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
959                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
960 
961                 eth_hw_addr_random(dev);
962 
963                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
964                 break;
965         }
966 }
967 
968 /* Character device part */
969 
970 /* Poll */
971 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
972 {
973         struct tun_file *tfile = file->private_data;
974         struct tun_struct *tun = __tun_get(tfile);
975         struct sock *sk;
976         unsigned int mask = 0;
977 
978         if (!tun)
979                 return POLLERR;
980 
981         sk = tfile->socket.sk;
982 
983         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
984 
985         poll_wait(file, sk_sleep(sk), wait);
986 
987         if (!skb_queue_empty(&sk->sk_receive_queue))
988                 mask |= POLLIN | POLLRDNORM;
989 
990         if (sock_writeable(sk) ||
991             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
992              sock_writeable(sk)))
993                 mask |= POLLOUT | POLLWRNORM;
994 
995         if (tun->dev->reg_state != NETREG_REGISTERED)
996                 mask = POLLERR;
997 
998         tun_put(tun);
999         return mask;
1000 }
1001 
1002 /* prepad is the amount to reserve at front.  len is length after that.
1003  * linear is a hint as to how much to copy (usually headers). */
1004 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1005                                      size_t prepad, size_t len,
1006                                      size_t linear, int noblock)
1007 {
1008         struct sock *sk = tfile->socket.sk;
1009         struct sk_buff *skb;
1010         int err;
1011 
1012         /* Under a page?  Don't bother with paged skb. */
1013         if (prepad + len < PAGE_SIZE || !linear)
1014                 linear = len;
1015 
1016         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1017                                    &err, 0);
1018         if (!skb)
1019                 return ERR_PTR(err);
1020 
1021         skb_reserve(skb, prepad);
1022         skb_put(skb, linear);
1023         skb->data_len = len - linear;
1024         skb->len += len - linear;
1025 
1026         return skb;
1027 }
1028 
1029 /* Get packet from user space buffer */
1030 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1031                             void *msg_control, struct iov_iter *from,
1032                             int noblock)
1033 {
1034         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1035         struct sk_buff *skb;
1036         size_t total_len = iov_iter_count(from);
1037         size_t len = total_len, align = NET_SKB_PAD, linear;
1038         struct virtio_net_hdr gso = { 0 };
1039         int good_linear;
1040         int copylen;
1041         bool zerocopy = false;
1042         int err;
1043         u32 rxhash;
1044         ssize_t n;
1045 
1046         if (!(tun->flags & IFF_NO_PI)) {
1047                 if (len < sizeof(pi))
1048                         return -EINVAL;
1049                 len -= sizeof(pi);
1050 
1051                 n = copy_from_iter(&pi, sizeof(pi), from);
1052                 if (n != sizeof(pi))
1053                         return -EFAULT;
1054         }
1055 
1056         if (tun->flags & IFF_VNET_HDR) {
1057                 if (len < tun->vnet_hdr_sz)
1058                         return -EINVAL;
1059                 len -= tun->vnet_hdr_sz;
1060 
1061                 n = copy_from_iter(&gso, sizeof(gso), from);
1062                 if (n != sizeof(gso))
1063                         return -EFAULT;
1064 
1065                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1066                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1067                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1068 
1069                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1070                         return -EINVAL;
1071                 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso));
1072         }
1073 
1074         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1075                 align += NET_IP_ALIGN;
1076                 if (unlikely(len < ETH_HLEN ||
1077                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1078                         return -EINVAL;
1079         }
1080 
1081         good_linear = SKB_MAX_HEAD(align);
1082 
1083         if (msg_control) {
1084                 struct iov_iter i = *from;
1085 
1086                 /* There are 256 bytes to be copied in skb, so there is
1087                  * enough room for skb expand head in case it is used.
1088                  * The rest of the buffer is mapped from userspace.
1089                  */
1090                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1091                 if (copylen > good_linear)
1092                         copylen = good_linear;
1093                 linear = copylen;
1094                 iov_iter_advance(&i, copylen);
1095                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1096                         zerocopy = true;
1097         }
1098 
1099         if (!zerocopy) {
1100                 copylen = len;
1101                 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1102                         linear = good_linear;
1103                 else
1104                         linear = tun16_to_cpu(tun, gso.hdr_len);
1105         }
1106 
1107         skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1108         if (IS_ERR(skb)) {
1109                 if (PTR_ERR(skb) != -EAGAIN)
1110                         tun->dev->stats.rx_dropped++;
1111                 return PTR_ERR(skb);
1112         }
1113 
1114         if (zerocopy)
1115                 err = zerocopy_sg_from_iter(skb, from);
1116         else {
1117                 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1118                 if (!err && msg_control) {
1119                         struct ubuf_info *uarg = msg_control;
1120                         uarg->callback(uarg, false);
1121                 }
1122         }
1123 
1124         if (err) {
1125                 tun->dev->stats.rx_dropped++;
1126                 kfree_skb(skb);
1127                 return -EFAULT;
1128         }
1129 
1130         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1131                 if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start),
1132                                           tun16_to_cpu(tun, gso.csum_offset))) {
1133                         tun->dev->stats.rx_frame_errors++;
1134                         kfree_skb(skb);
1135                         return -EINVAL;
1136                 }
1137         }
1138 
1139         switch (tun->flags & TUN_TYPE_MASK) {
1140         case IFF_TUN:
1141                 if (tun->flags & IFF_NO_PI) {
1142                         switch (skb->data[0] & 0xf0) {
1143                         case 0x40:
1144                                 pi.proto = htons(ETH_P_IP);
1145                                 break;
1146                         case 0x60:
1147                                 pi.proto = htons(ETH_P_IPV6);
1148                                 break;
1149                         default:
1150                                 tun->dev->stats.rx_dropped++;
1151                                 kfree_skb(skb);
1152                                 return -EINVAL;
1153                         }
1154                 }
1155 
1156                 skb_reset_mac_header(skb);
1157                 skb->protocol = pi.proto;
1158                 skb->dev = tun->dev;
1159                 break;
1160         case IFF_TAP:
1161                 skb->protocol = eth_type_trans(skb, tun->dev);
1162                 break;
1163         }
1164 
1165         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1166                 pr_debug("GSO!\n");
1167                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1168                 case VIRTIO_NET_HDR_GSO_TCPV4:
1169                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1170                         break;
1171                 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                 default:
1178                         tun->dev->stats.rx_frame_errors++;
1179                         kfree_skb(skb);
1180                         return -EINVAL;
1181                 }
1182 
1183                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1184                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1185 
1186                 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size);
1187                 if (skb_shinfo(skb)->gso_size == 0) {
1188                         tun->dev->stats.rx_frame_errors++;
1189                         kfree_skb(skb);
1190                         return -EINVAL;
1191                 }
1192 
1193                 /* Header must be checked, and gso_segs computed. */
1194                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1195                 skb_shinfo(skb)->gso_segs = 0;
1196         }
1197 
1198         /* copy skb_ubuf_info for callback when skb has no error */
1199         if (zerocopy) {
1200                 skb_shinfo(skb)->destructor_arg = msg_control;
1201                 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         skb_probe_transport_header(skb, 0);
1207 
1208         rxhash = skb_get_hash(skb);
1209         netif_rx_ni(skb);
1210 
1211         tun->dev->stats.rx_packets++;
1212         tun->dev->stats.rx_bytes += len;
1213 
1214         tun_flow_update(tun, rxhash, tfile);
1215         return total_len;
1216 }
1217 
1218 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1219 {
1220         struct file *file = iocb->ki_filp;
1221         struct tun_struct *tun = tun_get(file);
1222         struct tun_file *tfile = file->private_data;
1223         ssize_t result;
1224 
1225         if (!tun)
1226                 return -EBADFD;
1227 
1228         result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);
1229 
1230         tun_put(tun);
1231         return result;
1232 }
1233 
1234 /* Put packet to the user space buffer */
1235 static ssize_t tun_put_user(struct tun_struct *tun,
1236                             struct tun_file *tfile,
1237                             struct sk_buff *skb,
1238                             struct iov_iter *iter)
1239 {
1240         struct tun_pi pi = { 0, skb->protocol };
1241         ssize_t total;
1242         int vlan_offset = 0;
1243         int vlan_hlen = 0;
1244         int vnet_hdr_sz = 0;
1245 
1246         if (skb_vlan_tag_present(skb))
1247                 vlan_hlen = VLAN_HLEN;
1248 
1249         if (tun->flags & IFF_VNET_HDR)
1250                 vnet_hdr_sz = tun->vnet_hdr_sz;
1251 
1252         total = skb->len + vlan_hlen + vnet_hdr_sz;
1253 
1254         if (!(tun->flags & IFF_NO_PI)) {
1255                 if (iov_iter_count(iter) < sizeof(pi))
1256                         return -EINVAL;
1257 
1258                 total += sizeof(pi);
1259                 if (iov_iter_count(iter) < total) {
1260                         /* Packet will be striped */
1261                         pi.flags |= TUN_PKT_STRIP;
1262                 }
1263 
1264                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1265                         return -EFAULT;
1266         }
1267 
1268         if (vnet_hdr_sz) {
1269                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1270                 if (iov_iter_count(iter) < vnet_hdr_sz)
1271                         return -EINVAL;
1272 
1273                 if (skb_is_gso(skb)) {
1274                         struct skb_shared_info *sinfo = skb_shinfo(skb);
1275 
1276                         /* This is a hint as to how much should be linear. */
1277                         gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb));
1278                         gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size);
1279                         if (sinfo->gso_type & SKB_GSO_TCPV4)
1280                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1281                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
1282                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1283                         else if (sinfo->gso_type & SKB_GSO_UDP)
1284                                 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1285                         else {
1286                                 pr_err("unexpected GSO type: "
1287                                        "0x%x, gso_size %d, hdr_len %d\n",
1288                                        sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1289                                        tun16_to_cpu(tun, gso.hdr_len));
1290                                 print_hex_dump(KERN_ERR, "tun: ",
1291                                                DUMP_PREFIX_NONE,
1292                                                16, 1, skb->head,
1293                                                min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1294                                 WARN_ON_ONCE(1);
1295                                 return -EINVAL;
1296                         }
1297                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1298                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1299                 } else
1300                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1301 
1302                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1303                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1304                         gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) +
1305                                                       vlan_hlen);
1306                         gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset);
1307                 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1308                         gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1309                 } /* else everything is zero */
1310 
1311                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1312                         return -EFAULT;
1313 
1314                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1315         }
1316 
1317         if (vlan_hlen) {
1318                 int ret;
1319                 struct {
1320                         __be16 h_vlan_proto;
1321                         __be16 h_vlan_TCI;
1322                 } veth;
1323 
1324                 veth.h_vlan_proto = skb->vlan_proto;
1325                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1326 
1327                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1328 
1329                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1330                 if (ret || !iov_iter_count(iter))
1331                         goto done;
1332 
1333                 ret = copy_to_iter(&veth, sizeof(veth), iter);
1334                 if (ret != sizeof(veth) || !iov_iter_count(iter))
1335                         goto done;
1336         }
1337 
1338         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1339 
1340 done:
1341         tun->dev->stats.tx_packets++;
1342         tun->dev->stats.tx_bytes += skb->len + vlan_hlen;
1343 
1344         return total;
1345 }
1346 
1347 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1348                            struct iov_iter *to,
1349                            int noblock)
1350 {
1351         struct sk_buff *skb;
1352         ssize_t ret;
1353         int peeked, err, off = 0;
1354 
1355         tun_debug(KERN_INFO, tun, "tun_do_read\n");
1356 
1357         if (!iov_iter_count(to))
1358                 return 0;
1359 
1360         if (tun->dev->reg_state != NETREG_REGISTERED)
1361                 return -EIO;
1362 
1363         /* Read frames from queue */
1364         skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0,
1365                                   &peeked, &off, &err);
1366         if (!skb)
1367                 return err;
1368 
1369         ret = tun_put_user(tun, tfile, skb, to);
1370         if (unlikely(ret < 0))
1371                 kfree_skb(skb);
1372         else
1373                 consume_skb(skb);
1374 
1375         return ret;
1376 }
1377 
1378 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1379 {
1380         struct file *file = iocb->ki_filp;
1381         struct tun_file *tfile = file->private_data;
1382         struct tun_struct *tun = __tun_get(tfile);
1383         ssize_t len = iov_iter_count(to), ret;
1384 
1385         if (!tun)
1386                 return -EBADFD;
1387         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
1388         ret = min_t(ssize_t, ret, len);
1389         if (ret > 0)
1390                 iocb->ki_pos = ret;
1391         tun_put(tun);
1392         return ret;
1393 }
1394 
1395 static void tun_free_netdev(struct net_device *dev)
1396 {
1397         struct tun_struct *tun = netdev_priv(dev);
1398 
1399         BUG_ON(!(list_empty(&tun->disabled)));
1400         tun_flow_uninit(tun);
1401         security_tun_dev_free_security(tun->security);
1402         free_netdev(dev);
1403 }
1404 
1405 static void tun_setup(struct net_device *dev)
1406 {
1407         struct tun_struct *tun = netdev_priv(dev);
1408 
1409         tun->owner = INVALID_UID;
1410         tun->group = INVALID_GID;
1411 
1412         dev->ethtool_ops = &tun_ethtool_ops;
1413         dev->destructor = tun_free_netdev;
1414 }
1415 
1416 /* Trivial set of netlink ops to allow deleting tun or tap
1417  * device with netlink.
1418  */
1419 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1420 {
1421         return -EINVAL;
1422 }
1423 
1424 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1425         .kind           = DRV_NAME,
1426         .priv_size      = sizeof(struct tun_struct),
1427         .setup          = tun_setup,
1428         .validate       = tun_validate,
1429 };
1430 
1431 static void tun_sock_write_space(struct sock *sk)
1432 {
1433         struct tun_file *tfile;
1434         wait_queue_head_t *wqueue;
1435 
1436         if (!sock_writeable(sk))
1437                 return;
1438 
1439         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1440                 return;
1441 
1442         wqueue = sk_sleep(sk);
1443         if (wqueue && waitqueue_active(wqueue))
1444                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1445                                                 POLLWRNORM | POLLWRBAND);
1446 
1447         tfile = container_of(sk, struct tun_file, sk);
1448         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1449 }
1450 
1451 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1452 {
1453         int ret;
1454         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1455         struct tun_struct *tun = __tun_get(tfile);
1456 
1457         if (!tun)
1458                 return -EBADFD;
1459 
1460         ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1461                            m->msg_flags & MSG_DONTWAIT);
1462         tun_put(tun);
1463         return ret;
1464 }
1465 
1466 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1467                        int flags)
1468 {
1469         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1470         struct tun_struct *tun = __tun_get(tfile);
1471         int ret;
1472 
1473         if (!tun)
1474                 return -EBADFD;
1475 
1476         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1477                 ret = -EINVAL;
1478                 goto out;
1479         }
1480         if (flags & MSG_ERRQUEUE) {
1481                 ret = sock_recv_errqueue(sock->sk, m, total_len,
1482                                          SOL_PACKET, TUN_TX_TIMESTAMP);
1483                 goto out;
1484         }
1485         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1486         if (ret > (ssize_t)total_len) {
1487                 m->msg_flags |= MSG_TRUNC;
1488                 ret = flags & MSG_TRUNC ? ret : total_len;
1489         }
1490 out:
1491         tun_put(tun);
1492         return ret;
1493 }
1494 
1495 static int tun_release(struct socket *sock)
1496 {
1497         if (sock->sk)
1498                 sock_put(sock->sk);
1499         return 0;
1500 }
1501 
1502 /* Ops structure to mimic raw sockets with tun */
1503 static const struct proto_ops tun_socket_ops = {
1504         .sendmsg = tun_sendmsg,
1505         .recvmsg = tun_recvmsg,
1506         .release = tun_release,
1507 };
1508 
1509 static struct proto tun_proto = {
1510         .name           = "tun",
1511         .owner          = THIS_MODULE,
1512         .obj_size       = sizeof(struct tun_file),
1513 };
1514 
1515 static int tun_flags(struct tun_struct *tun)
1516 {
1517         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1518 }
1519 
1520 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1521                               char *buf)
1522 {
1523         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1524         return sprintf(buf, "0x%x\n", tun_flags(tun));
1525 }
1526 
1527 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1528                               char *buf)
1529 {
1530         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1531         return uid_valid(tun->owner)?
1532                 sprintf(buf, "%u\n",
1533                         from_kuid_munged(current_user_ns(), tun->owner)):
1534                 sprintf(buf, "-1\n");
1535 }
1536 
1537 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1538                               char *buf)
1539 {
1540         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1541         return gid_valid(tun->group) ?
1542                 sprintf(buf, "%u\n",
1543                         from_kgid_munged(current_user_ns(), tun->group)):
1544                 sprintf(buf, "-1\n");
1545 }
1546 
1547 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1548 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1549 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1550 
1551 static struct attribute *tun_dev_attrs[] = {
1552         &dev_attr_tun_flags.attr,
1553         &dev_attr_owner.attr,
1554         &dev_attr_group.attr,
1555         NULL
1556 };
1557 
1558 static const struct attribute_group tun_attr_group = {
1559         .attrs = tun_dev_attrs
1560 };
1561 
1562 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1563 {
1564         struct tun_struct *tun;
1565         struct tun_file *tfile = file->private_data;
1566         struct net_device *dev;
1567         int err;
1568 
1569         if (tfile->detached)
1570                 return -EINVAL;
1571 
1572         dev = __dev_get_by_name(net, ifr->ifr_name);
1573         if (dev) {
1574                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1575                         return -EBUSY;
1576                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1577                         tun = netdev_priv(dev);
1578                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1579                         tun = netdev_priv(dev);
1580                 else
1581                         return -EINVAL;
1582 
1583                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1584                     !!(tun->flags & IFF_MULTI_QUEUE))
1585                         return -EINVAL;
1586 
1587                 if (tun_not_capable(tun))
1588                         return -EPERM;
1589                 err = security_tun_dev_open(tun->security);
1590                 if (err < 0)
1591                         return err;
1592 
1593                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1594                 if (err < 0)
1595                         return err;
1596 
1597                 if (tun->flags & IFF_MULTI_QUEUE &&
1598                     (tun->numqueues + tun->numdisabled > 1)) {
1599                         /* One or more queue has already been attached, no need
1600                          * to initialize the device again.
1601                          */
1602                         return 0;
1603                 }
1604         }
1605         else {
1606                 char *name;
1607                 unsigned long flags = 0;
1608                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1609                              MAX_TAP_QUEUES : 1;
1610 
1611                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1612                         return -EPERM;
1613                 err = security_tun_dev_create();
1614                 if (err < 0)
1615                         return err;
1616 
1617                 /* Set dev type */
1618                 if (ifr->ifr_flags & IFF_TUN) {
1619                         /* TUN device */
1620                         flags |= IFF_TUN;
1621                         name = "tun%d";
1622                 } else if (ifr->ifr_flags & IFF_TAP) {
1623                         /* TAP device */
1624                         flags |= IFF_TAP;
1625                         name = "tap%d";
1626                 } else
1627                         return -EINVAL;
1628 
1629                 if (*ifr->ifr_name)
1630                         name = ifr->ifr_name;
1631 
1632                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1633                                        NET_NAME_UNKNOWN, tun_setup, queues,
1634                                        queues);
1635 
1636                 if (!dev)
1637                         return -ENOMEM;
1638 
1639                 dev_net_set(dev, net);
1640                 dev->rtnl_link_ops = &tun_link_ops;
1641                 dev->ifindex = tfile->ifindex;
1642                 dev->sysfs_groups[0] = &tun_attr_group;
1643 
1644                 tun = netdev_priv(dev);
1645                 tun->dev = dev;
1646                 tun->flags = flags;
1647                 tun->txflt.count = 0;
1648                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1649 
1650                 tun->filter_attached = false;
1651                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1652 
1653                 spin_lock_init(&tun->lock);
1654 
1655                 err = security_tun_dev_alloc_security(&tun->security);
1656                 if (err < 0)
1657                         goto err_free_dev;
1658 
1659                 tun_net_init(dev);
1660                 tun_flow_init(tun);
1661 
1662                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1663                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1664                                    NETIF_F_HW_VLAN_STAG_TX;
1665                 dev->features = dev->hw_features;
1666                 dev->vlan_features = dev->features &
1667                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
1668                                        NETIF_F_HW_VLAN_STAG_TX);
1669 
1670                 INIT_LIST_HEAD(&tun->disabled);
1671                 err = tun_attach(tun, file, false);
1672                 if (err < 0)
1673                         goto err_free_flow;
1674 
1675                 err = register_netdevice(tun->dev);
1676                 if (err < 0)
1677                         goto err_detach;
1678         }
1679 
1680         netif_carrier_on(tun->dev);
1681 
1682         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1683 
1684         tun->flags = (tun->flags & ~TUN_FEATURES) |
1685                 (ifr->ifr_flags & TUN_FEATURES);
1686 
1687         /* Make sure persistent devices do not get stuck in
1688          * xoff state.
1689          */
1690         if (netif_running(tun->dev))
1691                 netif_tx_wake_all_queues(tun->dev);
1692 
1693         strcpy(ifr->ifr_name, tun->dev->name);
1694         return 0;
1695 
1696 err_detach:
1697         tun_detach_all(dev);
1698 err_free_flow:
1699         tun_flow_uninit(tun);
1700         security_tun_dev_free_security(tun->security);
1701 err_free_dev:
1702         free_netdev(dev);
1703         return err;
1704 }
1705 
1706 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1707                        struct ifreq *ifr)
1708 {
1709         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1710 
1711         strcpy(ifr->ifr_name, tun->dev->name);
1712 
1713         ifr->ifr_flags = tun_flags(tun);
1714 
1715 }
1716 
1717 /* This is like a cut-down ethtool ops, except done via tun fd so no
1718  * privs required. */
1719 static int set_offload(struct tun_struct *tun, unsigned long arg)
1720 {
1721         netdev_features_t features = 0;
1722 
1723         if (arg & TUN_F_CSUM) {
1724                 features |= NETIF_F_HW_CSUM;
1725                 arg &= ~TUN_F_CSUM;
1726 
1727                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1728                         if (arg & TUN_F_TSO_ECN) {
1729                                 features |= NETIF_F_TSO_ECN;
1730                                 arg &= ~TUN_F_TSO_ECN;
1731                         }
1732                         if (arg & TUN_F_TSO4)
1733                                 features |= NETIF_F_TSO;
1734                         if (arg & TUN_F_TSO6)
1735                                 features |= NETIF_F_TSO6;
1736                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1737                 }
1738 
1739                 if (arg & TUN_F_UFO) {
1740                         features |= NETIF_F_UFO;
1741                         arg &= ~TUN_F_UFO;
1742                 }
1743         }
1744 
1745         /* This gives the user a way to test for new features in future by
1746          * trying to set them. */
1747         if (arg)
1748                 return -EINVAL;
1749 
1750         tun->set_features = features;
1751         netdev_update_features(tun->dev);
1752 
1753         return 0;
1754 }
1755 
1756 static void tun_detach_filter(struct tun_struct *tun, int n)
1757 {
1758         int i;
1759         struct tun_file *tfile;
1760 
1761         for (i = 0; i < n; i++) {
1762                 tfile = rtnl_dereference(tun->tfiles[i]);
1763                 sk_detach_filter(tfile->socket.sk);
1764         }
1765 
1766         tun->filter_attached = false;
1767 }
1768 
1769 static int tun_attach_filter(struct tun_struct *tun)
1770 {
1771         int i, ret = 0;
1772         struct tun_file *tfile;
1773 
1774         for (i = 0; i < tun->numqueues; i++) {
1775                 tfile = rtnl_dereference(tun->tfiles[i]);
1776                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1777                 if (ret) {
1778                         tun_detach_filter(tun, i);
1779                         return ret;
1780                 }
1781         }
1782 
1783         tun->filter_attached = true;
1784         return ret;
1785 }
1786 
1787 static void tun_set_sndbuf(struct tun_struct *tun)
1788 {
1789         struct tun_file *tfile;
1790         int i;
1791 
1792         for (i = 0; i < tun->numqueues; i++) {
1793                 tfile = rtnl_dereference(tun->tfiles[i]);
1794                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1795         }
1796 }
1797 
1798 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1799 {
1800         struct tun_file *tfile = file->private_data;
1801         struct tun_struct *tun;
1802         int ret = 0;
1803 
1804         rtnl_lock();
1805 
1806         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1807                 tun = tfile->detached;
1808                 if (!tun) {
1809                         ret = -EINVAL;
1810                         goto unlock;
1811                 }
1812                 ret = security_tun_dev_attach_queue(tun->security);
1813                 if (ret < 0)
1814                         goto unlock;
1815                 ret = tun_attach(tun, file, false);
1816         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1817                 tun = rtnl_dereference(tfile->tun);
1818                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1819                         ret = -EINVAL;
1820                 else
1821                         __tun_detach(tfile, false);
1822         } else
1823                 ret = -EINVAL;
1824 
1825 unlock:
1826         rtnl_unlock();
1827         return ret;
1828 }
1829 
1830 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1831                             unsigned long arg, int ifreq_len)
1832 {
1833         struct tun_file *tfile = file->private_data;
1834         struct tun_struct *tun;
1835         void __user* argp = (void __user*)arg;
1836         struct ifreq ifr;
1837         kuid_t owner;
1838         kgid_t group;
1839         int sndbuf;
1840         int vnet_hdr_sz;
1841         unsigned int ifindex;
1842         int le;
1843         int ret;
1844 
1845         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1846                 if (copy_from_user(&ifr, argp, ifreq_len))
1847                         return -EFAULT;
1848         } else {
1849                 memset(&ifr, 0, sizeof(ifr));
1850         }
1851         if (cmd == TUNGETFEATURES) {
1852                 /* Currently this just means: "what IFF flags are valid?".
1853                  * This is needed because we never checked for invalid flags on
1854                  * TUNSETIFF.
1855                  */
1856                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
1857                                 (unsigned int __user*)argp);
1858         } else if (cmd == TUNSETQUEUE)
1859                 return tun_set_queue(file, &ifr);
1860 
1861         ret = 0;
1862         rtnl_lock();
1863 
1864         tun = __tun_get(tfile);
1865         if (cmd == TUNSETIFF && !tun) {
1866                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1867 
1868                 ret = tun_set_iff(tfile->net, file, &ifr);
1869 
1870                 if (ret)
1871                         goto unlock;
1872 
1873                 if (copy_to_user(argp, &ifr, ifreq_len))
1874                         ret = -EFAULT;
1875                 goto unlock;
1876         }
1877         if (cmd == TUNSETIFINDEX) {
1878                 ret = -EPERM;
1879                 if (tun)
1880                         goto unlock;
1881 
1882                 ret = -EFAULT;
1883                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
1884                         goto unlock;
1885 
1886                 ret = 0;
1887                 tfile->ifindex = ifindex;
1888                 goto unlock;
1889         }
1890 
1891         ret = -EBADFD;
1892         if (!tun)
1893                 goto unlock;
1894 
1895         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1896 
1897         ret = 0;
1898         switch (cmd) {
1899         case TUNGETIFF:
1900                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1901 
1902                 if (tfile->detached)
1903                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
1904                 if (!tfile->socket.sk->sk_filter)
1905                         ifr.ifr_flags |= IFF_NOFILTER;
1906 
1907                 if (copy_to_user(argp, &ifr, ifreq_len))
1908                         ret = -EFAULT;
1909                 break;
1910 
1911         case TUNSETNOCSUM:
1912                 /* Disable/Enable checksum */
1913 
1914                 /* [unimplemented] */
1915                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1916                           arg ? "disabled" : "enabled");
1917                 break;
1918 
1919         case TUNSETPERSIST:
1920                 /* Disable/Enable persist mode. Keep an extra reference to the
1921                  * module to prevent the module being unprobed.
1922                  */
1923                 if (arg && !(tun->flags & IFF_PERSIST)) {
1924                         tun->flags |= IFF_PERSIST;
1925                         __module_get(THIS_MODULE);
1926                 }
1927                 if (!arg && (tun->flags & IFF_PERSIST)) {
1928                         tun->flags &= ~IFF_PERSIST;
1929                         module_put(THIS_MODULE);
1930                 }
1931 
1932                 tun_debug(KERN_INFO, tun, "persist %s\n",
1933                           arg ? "enabled" : "disabled");
1934                 break;
1935 
1936         case TUNSETOWNER:
1937                 /* Set owner of the device */
1938                 owner = make_kuid(current_user_ns(), arg);
1939                 if (!uid_valid(owner)) {
1940                         ret = -EINVAL;
1941                         break;
1942                 }
1943                 tun->owner = owner;
1944                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
1945                           from_kuid(&init_user_ns, tun->owner));
1946                 break;
1947 
1948         case TUNSETGROUP:
1949                 /* Set group of the device */
1950                 group = make_kgid(current_user_ns(), arg);
1951                 if (!gid_valid(group)) {
1952                         ret = -EINVAL;
1953                         break;
1954                 }
1955                 tun->group = group;
1956                 tun_debug(KERN_INFO, tun, "group set to %u\n",
1957                           from_kgid(&init_user_ns, tun->group));
1958                 break;
1959 
1960         case TUNSETLINK:
1961                 /* Only allow setting the type when the interface is down */
1962                 if (tun->dev->flags & IFF_UP) {
1963                         tun_debug(KERN_INFO, tun,
1964                                   "Linktype set failed because interface is up\n");
1965                         ret = -EBUSY;
1966                 } else {
1967                         tun->dev->type = (int) arg;
1968                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1969                                   tun->dev->type);
1970                         ret = 0;
1971                 }
1972                 break;
1973 
1974 #ifdef TUN_DEBUG
1975         case TUNSETDEBUG:
1976                 tun->debug = arg;
1977                 break;
1978 #endif
1979         case TUNSETOFFLOAD:
1980                 ret = set_offload(tun, arg);
1981                 break;
1982 
1983         case TUNSETTXFILTER:
1984                 /* Can be set only for TAPs */
1985                 ret = -EINVAL;
1986                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1987                         break;
1988                 ret = update_filter(&tun->txflt, (void __user *)arg);
1989                 break;
1990 
1991         case SIOCGIFHWADDR:
1992                 /* Get hw address */
1993                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1994                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1995                 if (copy_to_user(argp, &ifr, ifreq_len))
1996                         ret = -EFAULT;
1997                 break;
1998 
1999         case SIOCSIFHWADDR:
2000                 /* Set hw address */
2001                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2002                           ifr.ifr_hwaddr.sa_data);
2003 
2004                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2005                 break;
2006 
2007         case TUNGETSNDBUF:
2008                 sndbuf = tfile->socket.sk->sk_sndbuf;
2009                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2010                         ret = -EFAULT;
2011                 break;
2012 
2013         case TUNSETSNDBUF:
2014                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2015                         ret = -EFAULT;
2016                         break;
2017                 }
2018 
2019                 tun->sndbuf = sndbuf;
2020                 tun_set_sndbuf(tun);
2021                 break;
2022 
2023         case TUNGETVNETHDRSZ:
2024                 vnet_hdr_sz = tun->vnet_hdr_sz;
2025                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2026                         ret = -EFAULT;
2027                 break;
2028 
2029         case TUNSETVNETHDRSZ:
2030                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2031                         ret = -EFAULT;
2032                         break;
2033                 }
2034                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2035                         ret = -EINVAL;
2036                         break;
2037                 }
2038 
2039                 tun->vnet_hdr_sz = vnet_hdr_sz;
2040                 break;
2041 
2042         case TUNGETVNETLE:
2043                 le = !!(tun->flags & TUN_VNET_LE);
2044                 if (put_user(le, (int __user *)argp))
2045                         ret = -EFAULT;
2046                 break;
2047 
2048         case TUNSETVNETLE:
2049                 if (get_user(le, (int __user *)argp)) {
2050                         ret = -EFAULT;
2051                         break;
2052                 }
2053                 if (le)
2054                         tun->flags |= TUN_VNET_LE;
2055                 else
2056                         tun->flags &= ~TUN_VNET_LE;
2057                 break;
2058 
2059         case TUNATTACHFILTER:
2060                 /* Can be set only for TAPs */
2061                 ret = -EINVAL;
2062                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2063                         break;
2064                 ret = -EFAULT;
2065                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2066                         break;
2067 
2068                 ret = tun_attach_filter(tun);
2069                 break;
2070 
2071         case TUNDETACHFILTER:
2072                 /* Can be set only for TAPs */
2073                 ret = -EINVAL;
2074                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2075                         break;
2076                 ret = 0;
2077                 tun_detach_filter(tun, tun->numqueues);
2078                 break;
2079 
2080         case TUNGETFILTER:
2081                 ret = -EINVAL;
2082                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2083                         break;
2084                 ret = -EFAULT;
2085                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2086                         break;
2087                 ret = 0;
2088                 break;
2089 
2090         default:
2091                 ret = -EINVAL;
2092                 break;
2093         }
2094 
2095 unlock:
2096         rtnl_unlock();
2097         if (tun)
2098                 tun_put(tun);
2099         return ret;
2100 }
2101 
2102 static long tun_chr_ioctl(struct file *file,
2103                           unsigned int cmd, unsigned long arg)
2104 {
2105         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2106 }
2107 
2108 #ifdef CONFIG_COMPAT
2109 static long tun_chr_compat_ioctl(struct file *file,
2110                          unsigned int cmd, unsigned long arg)
2111 {
2112         switch (cmd) {
2113         case TUNSETIFF:
2114         case TUNGETIFF:
2115         case TUNSETTXFILTER:
2116         case TUNGETSNDBUF:
2117         case TUNSETSNDBUF:
2118         case SIOCGIFHWADDR:
2119         case SIOCSIFHWADDR:
2120                 arg = (unsigned long)compat_ptr(arg);
2121                 break;
2122         default:
2123                 arg = (compat_ulong_t)arg;
2124                 break;
2125         }
2126 
2127         /*
2128          * compat_ifreq is shorter than ifreq, so we must not access beyond
2129          * the end of that structure. All fields that are used in this
2130          * driver are compatible though, we don't need to convert the
2131          * contents.
2132          */
2133         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2134 }
2135 #endif /* CONFIG_COMPAT */
2136 
2137 static int tun_chr_fasync(int fd, struct file *file, int on)
2138 {
2139         struct tun_file *tfile = file->private_data;
2140         int ret;
2141 
2142         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2143                 goto out;
2144 
2145         if (on) {
2146                 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2147                 tfile->flags |= TUN_FASYNC;
2148         } else
2149                 tfile->flags &= ~TUN_FASYNC;
2150         ret = 0;
2151 out:
2152         return ret;
2153 }
2154 
2155 static int tun_chr_open(struct inode *inode, struct file * file)
2156 {
2157         struct tun_file *tfile;
2158 
2159         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2160 
2161         tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
2162                                             &tun_proto);
2163         if (!tfile)
2164                 return -ENOMEM;
2165         RCU_INIT_POINTER(tfile->tun, NULL);
2166         tfile->net = get_net(current->nsproxy->net_ns);
2167         tfile->flags = 0;
2168         tfile->ifindex = 0;
2169 
2170         init_waitqueue_head(&tfile->wq.wait);
2171         RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2172 
2173         tfile->socket.file = file;
2174         tfile->socket.ops = &tun_socket_ops;
2175 
2176         sock_init_data(&tfile->socket, &tfile->sk);
2177         sk_change_net(&tfile->sk, tfile->net);
2178 
2179         tfile->sk.sk_write_space = tun_sock_write_space;
2180         tfile->sk.sk_sndbuf = INT_MAX;
2181 
2182         file->private_data = tfile;
2183         set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
2184         INIT_LIST_HEAD(&tfile->next);
2185 
2186         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2187 
2188         return 0;
2189 }
2190 
2191 static int tun_chr_close(struct inode *inode, struct file *file)
2192 {
2193         struct tun_file *tfile = file->private_data;
2194         struct net *net = tfile->net;
2195 
2196         tun_detach(tfile, true);
2197         put_net(net);
2198 
2199         return 0;
2200 }
2201 
2202 #ifdef CONFIG_PROC_FS
2203 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2204 {
2205         struct tun_struct *tun;
2206         struct ifreq ifr;
2207 
2208         memset(&ifr, 0, sizeof(ifr));
2209 
2210         rtnl_lock();
2211         tun = tun_get(f);
2212         if (tun)
2213                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2214         rtnl_unlock();
2215 
2216         if (tun)
2217                 tun_put(tun);
2218 
2219         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2220 }
2221 #endif
2222 
2223 static const struct file_operations tun_fops = {
2224         .owner  = THIS_MODULE,
2225         .llseek = no_llseek,
2226         .read_iter  = tun_chr_read_iter,
2227         .write_iter = tun_chr_write_iter,
2228         .poll   = tun_chr_poll,
2229         .unlocked_ioctl = tun_chr_ioctl,
2230 #ifdef CONFIG_COMPAT
2231         .compat_ioctl = tun_chr_compat_ioctl,
2232 #endif
2233         .open   = tun_chr_open,
2234         .release = tun_chr_close,
2235         .fasync = tun_chr_fasync,
2236 #ifdef CONFIG_PROC_FS
2237         .show_fdinfo = tun_chr_show_fdinfo,
2238 #endif
2239 };
2240 
2241 static struct miscdevice tun_miscdev = {
2242         .minor = TUN_MINOR,
2243         .name = "tun",
2244         .nodename = "net/tun",
2245         .fops = &tun_fops,
2246 };
2247 
2248 /* ethtool interface */
2249 
2250 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2251 {
2252         cmd->supported          = 0;
2253         cmd->advertising        = 0;
2254         ethtool_cmd_speed_set(cmd, SPEED_10);
2255         cmd->duplex             = DUPLEX_FULL;
2256         cmd->port               = PORT_TP;
2257         cmd->phy_address        = 0;
2258         cmd->transceiver        = XCVR_INTERNAL;
2259         cmd->autoneg            = AUTONEG_DISABLE;
2260         cmd->maxtxpkt           = 0;
2261         cmd->maxrxpkt           = 0;
2262         return 0;
2263 }
2264 
2265 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2266 {
2267         struct tun_struct *tun = netdev_priv(dev);
2268 
2269         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2270         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2271 
2272         switch (tun->flags & TUN_TYPE_MASK) {
2273         case IFF_TUN:
2274                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2275                 break;
2276         case IFF_TAP:
2277                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2278                 break;
2279         }
2280 }
2281 
2282 static u32 tun_get_msglevel(struct net_device *dev)
2283 {
2284 #ifdef TUN_DEBUG
2285         struct tun_struct *tun = netdev_priv(dev);
2286         return tun->debug;
2287 #else
2288         return -EOPNOTSUPP;
2289 #endif
2290 }
2291 
2292 static void tun_set_msglevel(struct net_device *dev, u32 value)
2293 {
2294 #ifdef TUN_DEBUG
2295         struct tun_struct *tun = netdev_priv(dev);
2296         tun->debug = value;
2297 #endif
2298 }
2299 
2300 static const struct ethtool_ops tun_ethtool_ops = {
2301         .get_settings   = tun_get_settings,
2302         .get_drvinfo    = tun_get_drvinfo,
2303         .get_msglevel   = tun_get_msglevel,
2304         .set_msglevel   = tun_set_msglevel,
2305         .get_link       = ethtool_op_get_link,
2306         .get_ts_info    = ethtool_op_get_ts_info,
2307 };
2308 
2309 
2310 static int __init tun_init(void)
2311 {
2312         int ret = 0;
2313 
2314         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2315         pr_info("%s\n", DRV_COPYRIGHT);
2316 
2317         ret = rtnl_link_register(&tun_link_ops);
2318         if (ret) {
2319                 pr_err("Can't register link_ops\n");
2320                 goto err_linkops;
2321         }
2322 
2323         ret = misc_register(&tun_miscdev);
2324         if (ret) {
2325                 pr_err("Can't register misc device %d\n", TUN_MINOR);
2326                 goto err_misc;
2327         }
2328         return  0;
2329 err_misc:
2330         rtnl_link_unregister(&tun_link_ops);
2331 err_linkops:
2332         return ret;
2333 }
2334 
2335 static void tun_cleanup(void)
2336 {
2337         misc_deregister(&tun_miscdev);
2338         rtnl_link_unregister(&tun_link_ops);
2339 }
2340 
2341 /* Get an underlying socket object from tun file.  Returns error unless file is
2342  * attached to a device.  The returned object works like a packet socket, it
2343  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2344  * holding a reference to the file for as long as the socket is in use. */
2345 struct socket *tun_get_socket(struct file *file)
2346 {
2347         struct tun_file *tfile;
2348         if (file->f_op != &tun_fops)
2349                 return ERR_PTR(-EINVAL);
2350         tfile = file->private_data;
2351         if (!tfile)
2352                 return ERR_PTR(-EBADFD);
2353         return &tfile->socket;
2354 }
2355 EXPORT_SYMBOL_GPL(tun_get_socket);
2356 
2357 module_init(tun_init);
2358 module_exit(tun_cleanup);
2359 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2360 MODULE_AUTHOR(DRV_COPYRIGHT);
2361 MODULE_LICENSE("GPL");
2362 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2363 MODULE_ALIAS("devname:net/tun");
2364 

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