Version:  2.0.40 2.2.26 2.4.37 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19

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 /* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for
127  * the netdevice to be fit in one page. So we can make sure the success of
128  * memory allocation. TODO: increase the limit. */
129 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES
130 #define MAX_TAP_FLOWS  4096
131 
132 #define TUN_FLOW_EXPIRE (3 * HZ)
133 
134 /* A tun_file connects an open character device to a tuntap netdevice. It
135  * also contains all socket related structures (except sock_fprog and tap_filter)
136  * to serve as one transmit queue for tuntap device. The sock_fprog and
137  * tap_filter were kept in tun_struct since they were used for filtering for the
138  * netdevice not for a specific queue (at least I didn't see the requirement for
139  * this).
140  *
141  * RCU usage:
142  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
143  * other can only be read while rcu_read_lock or rtnl_lock is held.
144  */
145 struct tun_file {
146         struct sock sk;
147         struct socket socket;
148         struct socket_wq wq;
149         struct tun_struct __rcu *tun;
150         struct net *net;
151         struct fasync_struct *fasync;
152         /* only used for fasnyc */
153         unsigned int flags;
154         union {
155                 u16 queue_index;
156                 unsigned int ifindex;
157         };
158         struct list_head next;
159         struct tun_struct *detached;
160 };
161 
162 struct tun_flow_entry {
163         struct hlist_node hash_link;
164         struct rcu_head rcu;
165         struct tun_struct *tun;
166 
167         u32 rxhash;
168         u32 rps_rxhash;
169         int queue_index;
170         unsigned long updated;
171 };
172 
173 #define TUN_NUM_FLOW_ENTRIES 1024
174 
175 /* Since the socket were moved to tun_file, to preserve the behavior of persist
176  * device, socket filter, sndbuf and vnet header size were restore when the
177  * file were attached to a persist device.
178  */
179 struct tun_struct {
180         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
181         unsigned int            numqueues;
182         unsigned int            flags;
183         kuid_t                  owner;
184         kgid_t                  group;
185 
186         struct net_device       *dev;
187         netdev_features_t       set_features;
188 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
189                           NETIF_F_TSO6|NETIF_F_UFO)
190 
191         int                     vnet_hdr_sz;
192         int                     sndbuf;
193         struct tap_filter       txflt;
194         struct sock_fprog       fprog;
195         /* protected by rtnl lock */
196         bool                    filter_attached;
197 #ifdef TUN_DEBUG
198         int debug;
199 #endif
200         spinlock_t lock;
201         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
202         struct timer_list flow_gc_timer;
203         unsigned long ageing_time;
204         unsigned int numdisabled;
205         struct list_head disabled;
206         void *security;
207         u32 flow_count;
208 };
209 
210 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
211 {
212         return __virtio16_to_cpu(tun->flags & TUN_VNET_LE, val);
213 }
214 
215 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
216 {
217         return __cpu_to_virtio16(tun->flags & TUN_VNET_LE, val);
218 }
219 
220 static inline u32 tun_hashfn(u32 rxhash)
221 {
222         return rxhash & 0x3ff;
223 }
224 
225 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
226 {
227         struct tun_flow_entry *e;
228 
229         hlist_for_each_entry_rcu(e, head, hash_link) {
230                 if (e->rxhash == rxhash)
231                         return e;
232         }
233         return NULL;
234 }
235 
236 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
237                                               struct hlist_head *head,
238                                               u32 rxhash, u16 queue_index)
239 {
240         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
241 
242         if (e) {
243                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
244                           rxhash, queue_index);
245                 e->updated = jiffies;
246                 e->rxhash = rxhash;
247                 e->rps_rxhash = 0;
248                 e->queue_index = queue_index;
249                 e->tun = tun;
250                 hlist_add_head_rcu(&e->hash_link, head);
251                 ++tun->flow_count;
252         }
253         return e;
254 }
255 
256 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
257 {
258         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
259                   e->rxhash, e->queue_index);
260         sock_rps_reset_flow_hash(e->rps_rxhash);
261         hlist_del_rcu(&e->hash_link);
262         kfree_rcu(e, rcu);
263         --tun->flow_count;
264 }
265 
266 static void tun_flow_flush(struct tun_struct *tun)
267 {
268         int i;
269 
270         spin_lock_bh(&tun->lock);
271         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
272                 struct tun_flow_entry *e;
273                 struct hlist_node *n;
274 
275                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
276                         tun_flow_delete(tun, e);
277         }
278         spin_unlock_bh(&tun->lock);
279 }
280 
281 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
282 {
283         int i;
284 
285         spin_lock_bh(&tun->lock);
286         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
287                 struct tun_flow_entry *e;
288                 struct hlist_node *n;
289 
290                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
291                         if (e->queue_index == queue_index)
292                                 tun_flow_delete(tun, e);
293                 }
294         }
295         spin_unlock_bh(&tun->lock);
296 }
297 
298 static void tun_flow_cleanup(unsigned long data)
299 {
300         struct tun_struct *tun = (struct tun_struct *)data;
301         unsigned long delay = tun->ageing_time;
302         unsigned long next_timer = jiffies + delay;
303         unsigned long count = 0;
304         int i;
305 
306         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
307 
308         spin_lock_bh(&tun->lock);
309         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
310                 struct tun_flow_entry *e;
311                 struct hlist_node *n;
312 
313                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
314                         unsigned long this_timer;
315                         count++;
316                         this_timer = e->updated + delay;
317                         if (time_before_eq(this_timer, jiffies))
318                                 tun_flow_delete(tun, e);
319                         else if (time_before(this_timer, next_timer))
320                                 next_timer = this_timer;
321                 }
322         }
323 
324         if (count)
325                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
326         spin_unlock_bh(&tun->lock);
327 }
328 
329 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
330                             struct tun_file *tfile)
331 {
332         struct hlist_head *head;
333         struct tun_flow_entry *e;
334         unsigned long delay = tun->ageing_time;
335         u16 queue_index = tfile->queue_index;
336 
337         if (!rxhash)
338                 return;
339         else
340                 head = &tun->flows[tun_hashfn(rxhash)];
341 
342         rcu_read_lock();
343 
344         /* We may get a very small possibility of OOO during switching, not
345          * worth to optimize.*/
346         if (tun->numqueues == 1 || tfile->detached)
347                 goto unlock;
348 
349         e = tun_flow_find(head, rxhash);
350         if (likely(e)) {
351                 /* TODO: keep queueing to old queue until it's empty? */
352                 e->queue_index = queue_index;
353                 e->updated = jiffies;
354                 sock_rps_record_flow_hash(e->rps_rxhash);
355         } else {
356                 spin_lock_bh(&tun->lock);
357                 if (!tun_flow_find(head, rxhash) &&
358                     tun->flow_count < MAX_TAP_FLOWS)
359                         tun_flow_create(tun, head, rxhash, queue_index);
360 
361                 if (!timer_pending(&tun->flow_gc_timer))
362                         mod_timer(&tun->flow_gc_timer,
363                                   round_jiffies_up(jiffies + delay));
364                 spin_unlock_bh(&tun->lock);
365         }
366 
367 unlock:
368         rcu_read_unlock();
369 }
370 
371 /**
372  * Save the hash received in the stack receive path and update the
373  * flow_hash table accordingly.
374  */
375 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
376 {
377         if (unlikely(e->rps_rxhash != hash)) {
378                 sock_rps_reset_flow_hash(e->rps_rxhash);
379                 e->rps_rxhash = hash;
380         }
381 }
382 
383 /* We try to identify a flow through its rxhash first. The reason that
384  * we do not check rxq no. is because some cards(e.g 82599), chooses
385  * the rxq based on the txq where the last packet of the flow comes. As
386  * the userspace application move between processors, we may get a
387  * different rxq no. here. If we could not get rxhash, then we would
388  * hope the rxq no. may help here.
389  */
390 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
391                             void *accel_priv, select_queue_fallback_t fallback)
392 {
393         struct tun_struct *tun = netdev_priv(dev);
394         struct tun_flow_entry *e;
395         u32 txq = 0;
396         u32 numqueues = 0;
397 
398         rcu_read_lock();
399         numqueues = ACCESS_ONCE(tun->numqueues);
400 
401         txq = skb_get_hash(skb);
402         if (txq) {
403                 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
404                 if (e) {
405                         tun_flow_save_rps_rxhash(e, txq);
406                         txq = e->queue_index;
407                 } else
408                         /* use multiply and shift instead of expensive divide */
409                         txq = ((u64)txq * numqueues) >> 32;
410         } else if (likely(skb_rx_queue_recorded(skb))) {
411                 txq = skb_get_rx_queue(skb);
412                 while (unlikely(txq >= numqueues))
413                         txq -= numqueues;
414         }
415 
416         rcu_read_unlock();
417         return txq;
418 }
419 
420 static inline bool tun_not_capable(struct tun_struct *tun)
421 {
422         const struct cred *cred = current_cred();
423         struct net *net = dev_net(tun->dev);
424 
425         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
426                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
427                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
428 }
429 
430 static void tun_set_real_num_queues(struct tun_struct *tun)
431 {
432         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
433         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
434 }
435 
436 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
437 {
438         tfile->detached = tun;
439         list_add_tail(&tfile->next, &tun->disabled);
440         ++tun->numdisabled;
441 }
442 
443 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
444 {
445         struct tun_struct *tun = tfile->detached;
446 
447         tfile->detached = NULL;
448         list_del_init(&tfile->next);
449         --tun->numdisabled;
450         return tun;
451 }
452 
453 static void tun_queue_purge(struct tun_file *tfile)
454 {
455         skb_queue_purge(&tfile->sk.sk_receive_queue);
456         skb_queue_purge(&tfile->sk.sk_error_queue);
457 }
458 
459 static void __tun_detach(struct tun_file *tfile, bool clean)
460 {
461         struct tun_file *ntfile;
462         struct tun_struct *tun;
463 
464         tun = rtnl_dereference(tfile->tun);
465 
466         if (tun && !tfile->detached) {
467                 u16 index = tfile->queue_index;
468                 BUG_ON(index >= tun->numqueues);
469 
470                 rcu_assign_pointer(tun->tfiles[index],
471                                    tun->tfiles[tun->numqueues - 1]);
472                 ntfile = rtnl_dereference(tun->tfiles[index]);
473                 ntfile->queue_index = index;
474 
475                 --tun->numqueues;
476                 if (clean) {
477                         RCU_INIT_POINTER(tfile->tun, NULL);
478                         sock_put(&tfile->sk);
479                 } else
480                         tun_disable_queue(tun, tfile);
481 
482                 synchronize_net();
483                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
484                 /* Drop read queue */
485                 tun_queue_purge(tfile);
486                 tun_set_real_num_queues(tun);
487         } else if (tfile->detached && clean) {
488                 tun = tun_enable_queue(tfile);
489                 sock_put(&tfile->sk);
490         }
491 
492         if (clean) {
493                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
494                         netif_carrier_off(tun->dev);
495 
496                         if (!(tun->flags & IFF_PERSIST) &&
497                             tun->dev->reg_state == NETREG_REGISTERED)
498                                 unregister_netdevice(tun->dev);
499                 }
500 
501                 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
502                                  &tfile->socket.flags));
503                 sk_release_kernel(&tfile->sk);
504         }
505 }
506 
507 static void tun_detach(struct tun_file *tfile, bool clean)
508 {
509         rtnl_lock();
510         __tun_detach(tfile, clean);
511         rtnl_unlock();
512 }
513 
514 static void tun_detach_all(struct net_device *dev)
515 {
516         struct tun_struct *tun = netdev_priv(dev);
517         struct tun_file *tfile, *tmp;
518         int i, n = tun->numqueues;
519 
520         for (i = 0; i < n; i++) {
521                 tfile = rtnl_dereference(tun->tfiles[i]);
522                 BUG_ON(!tfile);
523                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
524                 RCU_INIT_POINTER(tfile->tun, NULL);
525                 --tun->numqueues;
526         }
527         list_for_each_entry(tfile, &tun->disabled, next) {
528                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
529                 RCU_INIT_POINTER(tfile->tun, NULL);
530         }
531         BUG_ON(tun->numqueues != 0);
532 
533         synchronize_net();
534         for (i = 0; i < n; i++) {
535                 tfile = rtnl_dereference(tun->tfiles[i]);
536                 /* Drop read queue */
537                 tun_queue_purge(tfile);
538                 sock_put(&tfile->sk);
539         }
540         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
541                 tun_enable_queue(tfile);
542                 tun_queue_purge(tfile);
543                 sock_put(&tfile->sk);
544         }
545         BUG_ON(tun->numdisabled != 0);
546 
547         if (tun->flags & IFF_PERSIST)
548                 module_put(THIS_MODULE);
549 }
550 
551 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
552 {
553         struct tun_file *tfile = file->private_data;
554         int err;
555 
556         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
557         if (err < 0)
558                 goto out;
559 
560         err = -EINVAL;
561         if (rtnl_dereference(tfile->tun) && !tfile->detached)
562                 goto out;
563 
564         err = -EBUSY;
565         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
566                 goto out;
567 
568         err = -E2BIG;
569         if (!tfile->detached &&
570             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
571                 goto out;
572 
573         err = 0;
574 
575         /* Re-attach the filter to persist device */
576         if (!skip_filter && (tun->filter_attached == true)) {
577                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
578                 if (!err)
579                         goto out;
580         }
581         tfile->queue_index = tun->numqueues;
582         rcu_assign_pointer(tfile->tun, tun);
583         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
584         tun->numqueues++;
585 
586         if (tfile->detached)
587                 tun_enable_queue(tfile);
588         else
589                 sock_hold(&tfile->sk);
590 
591         tun_set_real_num_queues(tun);
592 
593         /* device is allowed to go away first, so no need to hold extra
594          * refcnt.
595          */
596 
597 out:
598         return err;
599 }
600 
601 static struct tun_struct *__tun_get(struct tun_file *tfile)
602 {
603         struct tun_struct *tun;
604 
605         rcu_read_lock();
606         tun = rcu_dereference(tfile->tun);
607         if (tun)
608                 dev_hold(tun->dev);
609         rcu_read_unlock();
610 
611         return tun;
612 }
613 
614 static struct tun_struct *tun_get(struct file *file)
615 {
616         return __tun_get(file->private_data);
617 }
618 
619 static void tun_put(struct tun_struct *tun)
620 {
621         dev_put(tun->dev);
622 }
623 
624 /* TAP filtering */
625 static void addr_hash_set(u32 *mask, const u8 *addr)
626 {
627         int n = ether_crc(ETH_ALEN, addr) >> 26;
628         mask[n >> 5] |= (1 << (n & 31));
629 }
630 
631 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
632 {
633         int n = ether_crc(ETH_ALEN, addr) >> 26;
634         return mask[n >> 5] & (1 << (n & 31));
635 }
636 
637 static int update_filter(struct tap_filter *filter, void __user *arg)
638 {
639         struct { u8 u[ETH_ALEN]; } *addr;
640         struct tun_filter uf;
641         int err, alen, n, nexact;
642 
643         if (copy_from_user(&uf, arg, sizeof(uf)))
644                 return -EFAULT;
645 
646         if (!uf.count) {
647                 /* Disabled */
648                 filter->count = 0;
649                 return 0;
650         }
651 
652         alen = ETH_ALEN * uf.count;
653         addr = kmalloc(alen, GFP_KERNEL);
654         if (!addr)
655                 return -ENOMEM;
656 
657         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
658                 err = -EFAULT;
659                 goto done;
660         }
661 
662         /* The filter is updated without holding any locks. Which is
663          * perfectly safe. We disable it first and in the worst
664          * case we'll accept a few undesired packets. */
665         filter->count = 0;
666         wmb();
667 
668         /* Use first set of addresses as an exact filter */
669         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
670                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
671 
672         nexact = n;
673 
674         /* Remaining multicast addresses are hashed,
675          * unicast will leave the filter disabled. */
676         memset(filter->mask, 0, sizeof(filter->mask));
677         for (; n < uf.count; n++) {
678                 if (!is_multicast_ether_addr(addr[n].u)) {
679                         err = 0; /* no filter */
680                         goto done;
681                 }
682                 addr_hash_set(filter->mask, addr[n].u);
683         }
684 
685         /* For ALLMULTI just set the mask to all ones.
686          * This overrides the mask populated above. */
687         if ((uf.flags & TUN_FLT_ALLMULTI))
688                 memset(filter->mask, ~0, sizeof(filter->mask));
689 
690         /* Now enable the filter */
691         wmb();
692         filter->count = nexact;
693 
694         /* Return the number of exact filters */
695         err = nexact;
696 
697 done:
698         kfree(addr);
699         return err;
700 }
701 
702 /* Returns: 0 - drop, !=0 - accept */
703 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
704 {
705         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
706          * at this point. */
707         struct ethhdr *eh = (struct ethhdr *) skb->data;
708         int i;
709 
710         /* Exact match */
711         for (i = 0; i < filter->count; i++)
712                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
713                         return 1;
714 
715         /* Inexact match (multicast only) */
716         if (is_multicast_ether_addr(eh->h_dest))
717                 return addr_hash_test(filter->mask, eh->h_dest);
718 
719         return 0;
720 }
721 
722 /*
723  * Checks whether the packet is accepted or not.
724  * Returns: 0 - drop, !=0 - accept
725  */
726 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
727 {
728         if (!filter->count)
729                 return 1;
730 
731         return run_filter(filter, skb);
732 }
733 
734 /* Network device part of the driver */
735 
736 static const struct ethtool_ops tun_ethtool_ops;
737 
738 /* Net device detach from fd. */
739 static void tun_net_uninit(struct net_device *dev)
740 {
741         tun_detach_all(dev);
742 }
743 
744 /* Net device open. */
745 static int tun_net_open(struct net_device *dev)
746 {
747         netif_tx_start_all_queues(dev);
748         return 0;
749 }
750 
751 /* Net device close. */
752 static int tun_net_close(struct net_device *dev)
753 {
754         netif_tx_stop_all_queues(dev);
755         return 0;
756 }
757 
758 /* Net device start xmit */
759 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
760 {
761         struct tun_struct *tun = netdev_priv(dev);
762         int txq = skb->queue_mapping;
763         struct tun_file *tfile;
764         u32 numqueues = 0;
765 
766         rcu_read_lock();
767         tfile = rcu_dereference(tun->tfiles[txq]);
768         numqueues = ACCESS_ONCE(tun->numqueues);
769 
770         /* Drop packet if interface is not attached */
771         if (txq >= numqueues)
772                 goto drop;
773 
774         if (numqueues == 1) {
775                 /* Select queue was not called for the skbuff, so we extract the
776                  * RPS hash and save it into the flow_table here.
777                  */
778                 __u32 rxhash;
779 
780                 rxhash = skb_get_hash(skb);
781                 if (rxhash) {
782                         struct tun_flow_entry *e;
783                         e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
784                                         rxhash);
785                         if (e)
786                                 tun_flow_save_rps_rxhash(e, rxhash);
787                 }
788         }
789 
790         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
791 
792         BUG_ON(!tfile);
793 
794         /* Drop if the filter does not like it.
795          * This is a noop if the filter is disabled.
796          * Filter can be enabled only for the TAP devices. */
797         if (!check_filter(&tun->txflt, skb))
798                 goto drop;
799 
800         if (tfile->socket.sk->sk_filter &&
801             sk_filter(tfile->socket.sk, skb))
802                 goto drop;
803 
804         /* Limit the number of packets queued by dividing txq length with the
805          * number of queues.
806          */
807         if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues
808                           >= dev->tx_queue_len)
809                 goto drop;
810 
811         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
812                 goto drop;
813 
814         if (skb->sk) {
815                 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags);
816                 sw_tx_timestamp(skb);
817         }
818 
819         /* Orphan the skb - required as we might hang on to it
820          * for indefinite time.
821          */
822         skb_orphan(skb);
823 
824         nf_reset(skb);
825 
826         /* Enqueue packet */
827         skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
828 
829         /* Notify and wake up reader process */
830         if (tfile->flags & TUN_FASYNC)
831                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
832         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
833 
834         rcu_read_unlock();
835         return NETDEV_TX_OK;
836 
837 drop:
838         dev->stats.tx_dropped++;
839         skb_tx_error(skb);
840         kfree_skb(skb);
841         rcu_read_unlock();
842         return NET_XMIT_DROP;
843 }
844 
845 static void tun_net_mclist(struct net_device *dev)
846 {
847         /*
848          * This callback is supposed to deal with mc filter in
849          * _rx_ path and has nothing to do with the _tx_ path.
850          * In rx path we always accept everything userspace gives us.
851          */
852 }
853 
854 #define MIN_MTU 68
855 #define MAX_MTU 65535
856 
857 static int
858 tun_net_change_mtu(struct net_device *dev, int new_mtu)
859 {
860         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
861                 return -EINVAL;
862         dev->mtu = new_mtu;
863         return 0;
864 }
865 
866 static netdev_features_t tun_net_fix_features(struct net_device *dev,
867         netdev_features_t features)
868 {
869         struct tun_struct *tun = netdev_priv(dev);
870 
871         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
872 }
873 #ifdef CONFIG_NET_POLL_CONTROLLER
874 static void tun_poll_controller(struct net_device *dev)
875 {
876         /*
877          * Tun only receives frames when:
878          * 1) the char device endpoint gets data from user space
879          * 2) the tun socket gets a sendmsg call from user space
880          * Since both of those are synchronous operations, we are guaranteed
881          * never to have pending data when we poll for it
882          * so there is nothing to do here but return.
883          * We need this though so netpoll recognizes us as an interface that
884          * supports polling, which enables bridge devices in virt setups to
885          * still use netconsole
886          */
887         return;
888 }
889 #endif
890 static const struct net_device_ops tun_netdev_ops = {
891         .ndo_uninit             = tun_net_uninit,
892         .ndo_open               = tun_net_open,
893         .ndo_stop               = tun_net_close,
894         .ndo_start_xmit         = tun_net_xmit,
895         .ndo_change_mtu         = tun_net_change_mtu,
896         .ndo_fix_features       = tun_net_fix_features,
897         .ndo_select_queue       = tun_select_queue,
898 #ifdef CONFIG_NET_POLL_CONTROLLER
899         .ndo_poll_controller    = tun_poll_controller,
900 #endif
901 };
902 
903 static const struct net_device_ops tap_netdev_ops = {
904         .ndo_uninit             = tun_net_uninit,
905         .ndo_open               = tun_net_open,
906         .ndo_stop               = tun_net_close,
907         .ndo_start_xmit         = tun_net_xmit,
908         .ndo_change_mtu         = tun_net_change_mtu,
909         .ndo_fix_features       = tun_net_fix_features,
910         .ndo_set_rx_mode        = tun_net_mclist,
911         .ndo_set_mac_address    = eth_mac_addr,
912         .ndo_validate_addr      = eth_validate_addr,
913         .ndo_select_queue       = tun_select_queue,
914 #ifdef CONFIG_NET_POLL_CONTROLLER
915         .ndo_poll_controller    = tun_poll_controller,
916 #endif
917 };
918 
919 static void tun_flow_init(struct tun_struct *tun)
920 {
921         int i;
922 
923         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
924                 INIT_HLIST_HEAD(&tun->flows[i]);
925 
926         tun->ageing_time = TUN_FLOW_EXPIRE;
927         setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
928         mod_timer(&tun->flow_gc_timer,
929                   round_jiffies_up(jiffies + tun->ageing_time));
930 }
931 
932 static void tun_flow_uninit(struct tun_struct *tun)
933 {
934         del_timer_sync(&tun->flow_gc_timer);
935         tun_flow_flush(tun);
936 }
937 
938 /* Initialize net device. */
939 static void tun_net_init(struct net_device *dev)
940 {
941         struct tun_struct *tun = netdev_priv(dev);
942 
943         switch (tun->flags & TUN_TYPE_MASK) {
944         case IFF_TUN:
945                 dev->netdev_ops = &tun_netdev_ops;
946 
947                 /* Point-to-Point TUN Device */
948                 dev->hard_header_len = 0;
949                 dev->addr_len = 0;
950                 dev->mtu = 1500;
951 
952                 /* Zero header length */
953                 dev->type = ARPHRD_NONE;
954                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
955                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
956                 break;
957 
958         case IFF_TAP:
959                 dev->netdev_ops = &tap_netdev_ops;
960                 /* Ethernet TAP Device */
961                 ether_setup(dev);
962                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
963                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
964 
965                 eth_hw_addr_random(dev);
966 
967                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
968                 break;
969         }
970 }
971 
972 /* Character device part */
973 
974 /* Poll */
975 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
976 {
977         struct tun_file *tfile = file->private_data;
978         struct tun_struct *tun = __tun_get(tfile);
979         struct sock *sk;
980         unsigned int mask = 0;
981 
982         if (!tun)
983                 return POLLERR;
984 
985         sk = tfile->socket.sk;
986 
987         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
988 
989         poll_wait(file, sk_sleep(sk), wait);
990 
991         if (!skb_queue_empty(&sk->sk_receive_queue))
992                 mask |= POLLIN | POLLRDNORM;
993 
994         if (sock_writeable(sk) ||
995             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
996              sock_writeable(sk)))
997                 mask |= POLLOUT | POLLWRNORM;
998 
999         if (tun->dev->reg_state != NETREG_REGISTERED)
1000                 mask = POLLERR;
1001 
1002         tun_put(tun);
1003         return mask;
1004 }
1005 
1006 /* prepad is the amount to reserve at front.  len is length after that.
1007  * linear is a hint as to how much to copy (usually headers). */
1008 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1009                                      size_t prepad, size_t len,
1010                                      size_t linear, int noblock)
1011 {
1012         struct sock *sk = tfile->socket.sk;
1013         struct sk_buff *skb;
1014         int err;
1015 
1016         /* Under a page?  Don't bother with paged skb. */
1017         if (prepad + len < PAGE_SIZE || !linear)
1018                 linear = len;
1019 
1020         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1021                                    &err, 0);
1022         if (!skb)
1023                 return ERR_PTR(err);
1024 
1025         skb_reserve(skb, prepad);
1026         skb_put(skb, linear);
1027         skb->data_len = len - linear;
1028         skb->len += len - linear;
1029 
1030         return skb;
1031 }
1032 
1033 /* Get packet from user space buffer */
1034 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1035                             void *msg_control, struct iov_iter *from,
1036                             int noblock)
1037 {
1038         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1039         struct sk_buff *skb;
1040         size_t total_len = iov_iter_count(from);
1041         size_t len = total_len, align = NET_SKB_PAD, linear;
1042         struct virtio_net_hdr gso = { 0 };
1043         int good_linear;
1044         int copylen;
1045         bool zerocopy = false;
1046         int err;
1047         u32 rxhash;
1048         ssize_t n;
1049 
1050         if (!(tun->flags & IFF_NO_PI)) {
1051                 if (len < sizeof(pi))
1052                         return -EINVAL;
1053                 len -= sizeof(pi);
1054 
1055                 n = copy_from_iter(&pi, sizeof(pi), from);
1056                 if (n != sizeof(pi))
1057                         return -EFAULT;
1058         }
1059 
1060         if (tun->flags & IFF_VNET_HDR) {
1061                 if (len < tun->vnet_hdr_sz)
1062                         return -EINVAL;
1063                 len -= tun->vnet_hdr_sz;
1064 
1065                 n = copy_from_iter(&gso, sizeof(gso), from);
1066                 if (n != sizeof(gso))
1067                         return -EFAULT;
1068 
1069                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1070                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1071                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1072 
1073                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1074                         return -EINVAL;
1075                 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso));
1076         }
1077 
1078         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1079                 align += NET_IP_ALIGN;
1080                 if (unlikely(len < ETH_HLEN ||
1081                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1082                         return -EINVAL;
1083         }
1084 
1085         good_linear = SKB_MAX_HEAD(align);
1086 
1087         if (msg_control) {
1088                 struct iov_iter i = *from;
1089 
1090                 /* There are 256 bytes to be copied in skb, so there is
1091                  * enough room for skb expand head in case it is used.
1092                  * The rest of the buffer is mapped from userspace.
1093                  */
1094                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1095                 if (copylen > good_linear)
1096                         copylen = good_linear;
1097                 linear = copylen;
1098                 iov_iter_advance(&i, copylen);
1099                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1100                         zerocopy = true;
1101         }
1102 
1103         if (!zerocopy) {
1104                 copylen = len;
1105                 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1106                         linear = good_linear;
1107                 else
1108                         linear = tun16_to_cpu(tun, gso.hdr_len);
1109         }
1110 
1111         skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1112         if (IS_ERR(skb)) {
1113                 if (PTR_ERR(skb) != -EAGAIN)
1114                         tun->dev->stats.rx_dropped++;
1115                 return PTR_ERR(skb);
1116         }
1117 
1118         if (zerocopy)
1119                 err = zerocopy_sg_from_iter(skb, from);
1120         else {
1121                 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1122                 if (!err && msg_control) {
1123                         struct ubuf_info *uarg = msg_control;
1124                         uarg->callback(uarg, false);
1125                 }
1126         }
1127 
1128         if (err) {
1129                 tun->dev->stats.rx_dropped++;
1130                 kfree_skb(skb);
1131                 return -EFAULT;
1132         }
1133 
1134         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1135                 if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start),
1136                                           tun16_to_cpu(tun, gso.csum_offset))) {
1137                         tun->dev->stats.rx_frame_errors++;
1138                         kfree_skb(skb);
1139                         return -EINVAL;
1140                 }
1141         }
1142 
1143         switch (tun->flags & TUN_TYPE_MASK) {
1144         case IFF_TUN:
1145                 if (tun->flags & IFF_NO_PI) {
1146                         switch (skb->data[0] & 0xf0) {
1147                         case 0x40:
1148                                 pi.proto = htons(ETH_P_IP);
1149                                 break;
1150                         case 0x60:
1151                                 pi.proto = htons(ETH_P_IPV6);
1152                                 break;
1153                         default:
1154                                 tun->dev->stats.rx_dropped++;
1155                                 kfree_skb(skb);
1156                                 return -EINVAL;
1157                         }
1158                 }
1159 
1160                 skb_reset_mac_header(skb);
1161                 skb->protocol = pi.proto;
1162                 skb->dev = tun->dev;
1163                 break;
1164         case IFF_TAP:
1165                 skb->protocol = eth_type_trans(skb, tun->dev);
1166                 break;
1167         }
1168 
1169         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1170                 pr_debug("GSO!\n");
1171                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1172                 case VIRTIO_NET_HDR_GSO_TCPV4:
1173                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1174                         break;
1175                 case VIRTIO_NET_HDR_GSO_TCPV6:
1176                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1177                         break;
1178                 case VIRTIO_NET_HDR_GSO_UDP:
1179                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1180                         break;
1181                 default:
1182                         tun->dev->stats.rx_frame_errors++;
1183                         kfree_skb(skb);
1184                         return -EINVAL;
1185                 }
1186 
1187                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1188                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1189 
1190                 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size);
1191                 if (skb_shinfo(skb)->gso_size == 0) {
1192                         tun->dev->stats.rx_frame_errors++;
1193                         kfree_skb(skb);
1194                         return -EINVAL;
1195                 }
1196 
1197                 /* Header must be checked, and gso_segs computed. */
1198                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1199                 skb_shinfo(skb)->gso_segs = 0;
1200         }
1201 
1202         /* copy skb_ubuf_info for callback when skb has no error */
1203         if (zerocopy) {
1204                 skb_shinfo(skb)->destructor_arg = msg_control;
1205                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1206                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1207         }
1208 
1209         skb_reset_network_header(skb);
1210         skb_probe_transport_header(skb, 0);
1211 
1212         rxhash = skb_get_hash(skb);
1213         netif_rx_ni(skb);
1214 
1215         tun->dev->stats.rx_packets++;
1216         tun->dev->stats.rx_bytes += len;
1217 
1218         tun_flow_update(tun, rxhash, tfile);
1219         return total_len;
1220 }
1221 
1222 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1223 {
1224         struct file *file = iocb->ki_filp;
1225         struct tun_struct *tun = tun_get(file);
1226         struct tun_file *tfile = file->private_data;
1227         ssize_t result;
1228 
1229         if (!tun)
1230                 return -EBADFD;
1231 
1232         result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);
1233 
1234         tun_put(tun);
1235         return result;
1236 }
1237 
1238 /* Put packet to the user space buffer */
1239 static ssize_t tun_put_user(struct tun_struct *tun,
1240                             struct tun_file *tfile,
1241                             struct sk_buff *skb,
1242                             struct iov_iter *iter)
1243 {
1244         struct tun_pi pi = { 0, skb->protocol };
1245         ssize_t total;
1246         int vlan_offset = 0;
1247         int vlan_hlen = 0;
1248         int vnet_hdr_sz = 0;
1249 
1250         if (vlan_tx_tag_present(skb))
1251                 vlan_hlen = VLAN_HLEN;
1252 
1253         if (tun->flags & IFF_VNET_HDR)
1254                 vnet_hdr_sz = tun->vnet_hdr_sz;
1255 
1256         total = skb->len + vlan_hlen + vnet_hdr_sz;
1257 
1258         if (!(tun->flags & IFF_NO_PI)) {
1259                 if (iov_iter_count(iter) < sizeof(pi))
1260                         return -EINVAL;
1261 
1262                 total += sizeof(pi);
1263                 if (iov_iter_count(iter) < total) {
1264                         /* Packet will be striped */
1265                         pi.flags |= TUN_PKT_STRIP;
1266                 }
1267 
1268                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1269                         return -EFAULT;
1270         }
1271 
1272         if (vnet_hdr_sz) {
1273                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1274                 if (iov_iter_count(iter) < vnet_hdr_sz)
1275                         return -EINVAL;
1276 
1277                 if (skb_is_gso(skb)) {
1278                         struct skb_shared_info *sinfo = skb_shinfo(skb);
1279 
1280                         /* This is a hint as to how much should be linear. */
1281                         gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb));
1282                         gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size);
1283                         if (sinfo->gso_type & SKB_GSO_TCPV4)
1284                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1285                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
1286                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1287                         else if (sinfo->gso_type & SKB_GSO_UDP)
1288                                 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1289                         else {
1290                                 pr_err("unexpected GSO type: "
1291                                        "0x%x, gso_size %d, hdr_len %d\n",
1292                                        sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1293                                        tun16_to_cpu(tun, gso.hdr_len));
1294                                 print_hex_dump(KERN_ERR, "tun: ",
1295                                                DUMP_PREFIX_NONE,
1296                                                16, 1, skb->head,
1297                                                min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1298                                 WARN_ON_ONCE(1);
1299                                 return -EINVAL;
1300                         }
1301                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1302                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1303                 } else
1304                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1305 
1306                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1307                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1308                         gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) +
1309                                                       vlan_hlen);
1310                         gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset);
1311                 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1312                         gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1313                 } /* else everything is zero */
1314 
1315                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1316                         return -EFAULT;
1317 
1318                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1319         }
1320 
1321         if (vlan_hlen) {
1322                 int ret;
1323                 struct {
1324                         __be16 h_vlan_proto;
1325                         __be16 h_vlan_TCI;
1326                 } veth;
1327 
1328                 veth.h_vlan_proto = skb->vlan_proto;
1329                 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb));
1330 
1331                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1332 
1333                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1334                 if (ret || !iov_iter_count(iter))
1335                         goto done;
1336 
1337                 ret = copy_to_iter(&veth, sizeof(veth), iter);
1338                 if (ret != sizeof(veth) || !iov_iter_count(iter))
1339                         goto done;
1340         }
1341 
1342         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1343 
1344 done:
1345         tun->dev->stats.tx_packets++;
1346         tun->dev->stats.tx_bytes += skb->len + vlan_hlen;
1347 
1348         return total;
1349 }
1350 
1351 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1352                            struct iov_iter *to,
1353                            int noblock)
1354 {
1355         struct sk_buff *skb;
1356         ssize_t ret;
1357         int peeked, err, off = 0;
1358 
1359         tun_debug(KERN_INFO, tun, "tun_do_read\n");
1360 
1361         if (!iov_iter_count(to))
1362                 return 0;
1363 
1364         if (tun->dev->reg_state != NETREG_REGISTERED)
1365                 return -EIO;
1366 
1367         /* Read frames from queue */
1368         skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0,
1369                                   &peeked, &off, &err);
1370         if (!skb)
1371                 return 0;
1372 
1373         ret = tun_put_user(tun, tfile, skb, to);
1374         if (unlikely(ret < 0))
1375                 kfree_skb(skb);
1376         else
1377                 consume_skb(skb);
1378 
1379         return ret;
1380 }
1381 
1382 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1383 {
1384         struct file *file = iocb->ki_filp;
1385         struct tun_file *tfile = file->private_data;
1386         struct tun_struct *tun = __tun_get(tfile);
1387         ssize_t len = iov_iter_count(to), ret;
1388 
1389         if (!tun)
1390                 return -EBADFD;
1391         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
1392         ret = min_t(ssize_t, ret, len);
1393         if (ret > 0)
1394                 iocb->ki_pos = ret;
1395         tun_put(tun);
1396         return ret;
1397 }
1398 
1399 static void tun_free_netdev(struct net_device *dev)
1400 {
1401         struct tun_struct *tun = netdev_priv(dev);
1402 
1403         BUG_ON(!(list_empty(&tun->disabled)));
1404         tun_flow_uninit(tun);
1405         security_tun_dev_free_security(tun->security);
1406         free_netdev(dev);
1407 }
1408 
1409 static void tun_setup(struct net_device *dev)
1410 {
1411         struct tun_struct *tun = netdev_priv(dev);
1412 
1413         tun->owner = INVALID_UID;
1414         tun->group = INVALID_GID;
1415 
1416         dev->ethtool_ops = &tun_ethtool_ops;
1417         dev->destructor = tun_free_netdev;
1418 }
1419 
1420 /* Trivial set of netlink ops to allow deleting tun or tap
1421  * device with netlink.
1422  */
1423 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1424 {
1425         return -EINVAL;
1426 }
1427 
1428 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1429         .kind           = DRV_NAME,
1430         .priv_size      = sizeof(struct tun_struct),
1431         .setup          = tun_setup,
1432         .validate       = tun_validate,
1433 };
1434 
1435 static void tun_sock_write_space(struct sock *sk)
1436 {
1437         struct tun_file *tfile;
1438         wait_queue_head_t *wqueue;
1439 
1440         if (!sock_writeable(sk))
1441                 return;
1442 
1443         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1444                 return;
1445 
1446         wqueue = sk_sleep(sk);
1447         if (wqueue && waitqueue_active(wqueue))
1448                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1449                                                 POLLWRNORM | POLLWRBAND);
1450 
1451         tfile = container_of(sk, struct tun_file, sk);
1452         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1453 }
1454 
1455 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1456                        struct msghdr *m, size_t total_len)
1457 {
1458         int ret;
1459         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1460         struct tun_struct *tun = __tun_get(tfile);
1461 
1462         if (!tun)
1463                 return -EBADFD;
1464 
1465         ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1466                            m->msg_flags & MSG_DONTWAIT);
1467         tun_put(tun);
1468         return ret;
1469 }
1470 
1471 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1472                        struct msghdr *m, size_t total_len,
1473                        int flags)
1474 {
1475         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1476         struct tun_struct *tun = __tun_get(tfile);
1477         int ret;
1478 
1479         if (!tun)
1480                 return -EBADFD;
1481 
1482         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1483                 ret = -EINVAL;
1484                 goto out;
1485         }
1486         if (flags & MSG_ERRQUEUE) {
1487                 ret = sock_recv_errqueue(sock->sk, m, total_len,
1488                                          SOL_PACKET, TUN_TX_TIMESTAMP);
1489                 goto out;
1490         }
1491         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1492         if (ret > total_len) {
1493                 m->msg_flags |= MSG_TRUNC;
1494                 ret = flags & MSG_TRUNC ? ret : total_len;
1495         }
1496 out:
1497         tun_put(tun);
1498         return ret;
1499 }
1500 
1501 static int tun_release(struct socket *sock)
1502 {
1503         if (sock->sk)
1504                 sock_put(sock->sk);
1505         return 0;
1506 }
1507 
1508 /* Ops structure to mimic raw sockets with tun */
1509 static const struct proto_ops tun_socket_ops = {
1510         .sendmsg = tun_sendmsg,
1511         .recvmsg = tun_recvmsg,
1512         .release = tun_release,
1513 };
1514 
1515 static struct proto tun_proto = {
1516         .name           = "tun",
1517         .owner          = THIS_MODULE,
1518         .obj_size       = sizeof(struct tun_file),
1519 };
1520 
1521 static int tun_flags(struct tun_struct *tun)
1522 {
1523         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1524 }
1525 
1526 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1527                               char *buf)
1528 {
1529         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1530         return sprintf(buf, "0x%x\n", tun_flags(tun));
1531 }
1532 
1533 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1534                               char *buf)
1535 {
1536         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1537         return uid_valid(tun->owner)?
1538                 sprintf(buf, "%u\n",
1539                         from_kuid_munged(current_user_ns(), tun->owner)):
1540                 sprintf(buf, "-1\n");
1541 }
1542 
1543 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1544                               char *buf)
1545 {
1546         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1547         return gid_valid(tun->group) ?
1548                 sprintf(buf, "%u\n",
1549                         from_kgid_munged(current_user_ns(), tun->group)):
1550                 sprintf(buf, "-1\n");
1551 }
1552 
1553 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1554 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1555 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1556 
1557 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1558 {
1559         struct tun_struct *tun;
1560         struct tun_file *tfile = file->private_data;
1561         struct net_device *dev;
1562         int err;
1563 
1564         if (tfile->detached)
1565                 return -EINVAL;
1566 
1567         dev = __dev_get_by_name(net, ifr->ifr_name);
1568         if (dev) {
1569                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1570                         return -EBUSY;
1571                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1572                         tun = netdev_priv(dev);
1573                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1574                         tun = netdev_priv(dev);
1575                 else
1576                         return -EINVAL;
1577 
1578                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1579                     !!(tun->flags & IFF_MULTI_QUEUE))
1580                         return -EINVAL;
1581 
1582                 if (tun_not_capable(tun))
1583                         return -EPERM;
1584                 err = security_tun_dev_open(tun->security);
1585                 if (err < 0)
1586                         return err;
1587 
1588                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1589                 if (err < 0)
1590                         return err;
1591 
1592                 if (tun->flags & IFF_MULTI_QUEUE &&
1593                     (tun->numqueues + tun->numdisabled > 1)) {
1594                         /* One or more queue has already been attached, no need
1595                          * to initialize the device again.
1596                          */
1597                         return 0;
1598                 }
1599         }
1600         else {
1601                 char *name;
1602                 unsigned long flags = 0;
1603                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1604                              MAX_TAP_QUEUES : 1;
1605 
1606                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1607                         return -EPERM;
1608                 err = security_tun_dev_create();
1609                 if (err < 0)
1610                         return err;
1611 
1612                 /* Set dev type */
1613                 if (ifr->ifr_flags & IFF_TUN) {
1614                         /* TUN device */
1615                         flags |= IFF_TUN;
1616                         name = "tun%d";
1617                 } else if (ifr->ifr_flags & IFF_TAP) {
1618                         /* TAP device */
1619                         flags |= IFF_TAP;
1620                         name = "tap%d";
1621                 } else
1622                         return -EINVAL;
1623 
1624                 if (*ifr->ifr_name)
1625                         name = ifr->ifr_name;
1626 
1627                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1628                                        NET_NAME_UNKNOWN, tun_setup, queues,
1629                                        queues);
1630 
1631                 if (!dev)
1632                         return -ENOMEM;
1633 
1634                 dev_net_set(dev, net);
1635                 dev->rtnl_link_ops = &tun_link_ops;
1636                 dev->ifindex = tfile->ifindex;
1637 
1638                 tun = netdev_priv(dev);
1639                 tun->dev = dev;
1640                 tun->flags = flags;
1641                 tun->txflt.count = 0;
1642                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1643 
1644                 tun->filter_attached = false;
1645                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1646 
1647                 spin_lock_init(&tun->lock);
1648 
1649                 err = security_tun_dev_alloc_security(&tun->security);
1650                 if (err < 0)
1651                         goto err_free_dev;
1652 
1653                 tun_net_init(dev);
1654                 tun_flow_init(tun);
1655 
1656                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1657                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1658                                    NETIF_F_HW_VLAN_STAG_TX;
1659                 dev->features = dev->hw_features;
1660                 dev->vlan_features = dev->features &
1661                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
1662                                        NETIF_F_HW_VLAN_STAG_TX);
1663 
1664                 INIT_LIST_HEAD(&tun->disabled);
1665                 err = tun_attach(tun, file, false);
1666                 if (err < 0)
1667                         goto err_free_flow;
1668 
1669                 err = register_netdevice(tun->dev);
1670                 if (err < 0)
1671                         goto err_detach;
1672 
1673                 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1674                     device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1675                     device_create_file(&tun->dev->dev, &dev_attr_group))
1676                         pr_err("Failed to create tun sysfs files\n");
1677         }
1678 
1679         netif_carrier_on(tun->dev);
1680 
1681         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1682 
1683         tun->flags = (tun->flags & ~TUN_FEATURES) |
1684                 (ifr->ifr_flags & TUN_FEATURES);
1685 
1686         /* Make sure persistent devices do not get stuck in
1687          * xoff state.
1688          */
1689         if (netif_running(tun->dev))
1690                 netif_tx_wake_all_queues(tun->dev);
1691 
1692         strcpy(ifr->ifr_name, tun->dev->name);
1693         return 0;
1694 
1695 err_detach:
1696         tun_detach_all(dev);
1697 err_free_flow:
1698         tun_flow_uninit(tun);
1699         security_tun_dev_free_security(tun->security);
1700 err_free_dev:
1701         free_netdev(dev);
1702         return err;
1703 }
1704 
1705 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1706                        struct ifreq *ifr)
1707 {
1708         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1709 
1710         strcpy(ifr->ifr_name, tun->dev->name);
1711 
1712         ifr->ifr_flags = tun_flags(tun);
1713 
1714 }
1715 
1716 /* This is like a cut-down ethtool ops, except done via tun fd so no
1717  * privs required. */
1718 static int set_offload(struct tun_struct *tun, unsigned long arg)
1719 {
1720         netdev_features_t features = 0;
1721 
1722         if (arg & TUN_F_CSUM) {
1723                 features |= NETIF_F_HW_CSUM;
1724                 arg &= ~TUN_F_CSUM;
1725 
1726                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1727                         if (arg & TUN_F_TSO_ECN) {
1728                                 features |= NETIF_F_TSO_ECN;
1729                                 arg &= ~TUN_F_TSO_ECN;
1730                         }
1731                         if (arg & TUN_F_TSO4)
1732                                 features |= NETIF_F_TSO;
1733                         if (arg & TUN_F_TSO6)
1734                                 features |= NETIF_F_TSO6;
1735                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1736                 }
1737 
1738                 if (arg & TUN_F_UFO) {
1739                         features |= NETIF_F_UFO;
1740                         arg &= ~TUN_F_UFO;
1741                 }
1742         }
1743 
1744         /* This gives the user a way to test for new features in future by
1745          * trying to set them. */
1746         if (arg)
1747                 return -EINVAL;
1748 
1749         tun->set_features = features;
1750         netdev_update_features(tun->dev);
1751 
1752         return 0;
1753 }
1754 
1755 static void tun_detach_filter(struct tun_struct *tun, int n)
1756 {
1757         int i;
1758         struct tun_file *tfile;
1759 
1760         for (i = 0; i < n; i++) {
1761                 tfile = rtnl_dereference(tun->tfiles[i]);
1762                 sk_detach_filter(tfile->socket.sk);
1763         }
1764 
1765         tun->filter_attached = false;
1766 }
1767 
1768 static int tun_attach_filter(struct tun_struct *tun)
1769 {
1770         int i, ret = 0;
1771         struct tun_file *tfile;
1772 
1773         for (i = 0; i < tun->numqueues; i++) {
1774                 tfile = rtnl_dereference(tun->tfiles[i]);
1775                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1776                 if (ret) {
1777                         tun_detach_filter(tun, i);
1778                         return ret;
1779                 }
1780         }
1781 
1782         tun->filter_attached = true;
1783         return ret;
1784 }
1785 
1786 static void tun_set_sndbuf(struct tun_struct *tun)
1787 {
1788         struct tun_file *tfile;
1789         int i;
1790 
1791         for (i = 0; i < tun->numqueues; i++) {
1792                 tfile = rtnl_dereference(tun->tfiles[i]);
1793                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1794         }
1795 }
1796 
1797 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1798 {
1799         struct tun_file *tfile = file->private_data;
1800         struct tun_struct *tun;
1801         int ret = 0;
1802 
1803         rtnl_lock();
1804 
1805         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1806                 tun = tfile->detached;
1807                 if (!tun) {
1808                         ret = -EINVAL;
1809                         goto unlock;
1810                 }
1811                 ret = security_tun_dev_attach_queue(tun->security);
1812                 if (ret < 0)
1813                         goto unlock;
1814                 ret = tun_attach(tun, file, false);
1815         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1816                 tun = rtnl_dereference(tfile->tun);
1817                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1818                         ret = -EINVAL;
1819                 else
1820                         __tun_detach(tfile, false);
1821         } else
1822                 ret = -EINVAL;
1823 
1824 unlock:
1825         rtnl_unlock();
1826         return ret;
1827 }
1828 
1829 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1830                             unsigned long arg, int ifreq_len)
1831 {
1832         struct tun_file *tfile = file->private_data;
1833         struct tun_struct *tun;
1834         void __user* argp = (void __user*)arg;
1835         struct ifreq ifr;
1836         kuid_t owner;
1837         kgid_t group;
1838         int sndbuf;
1839         int vnet_hdr_sz;
1840         unsigned int ifindex;
1841         int le;
1842         int ret;
1843 
1844         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1845                 if (copy_from_user(&ifr, argp, ifreq_len))
1846                         return -EFAULT;
1847         } else {
1848                 memset(&ifr, 0, sizeof(ifr));
1849         }
1850         if (cmd == TUNGETFEATURES) {
1851                 /* Currently this just means: "what IFF flags are valid?".
1852                  * This is needed because we never checked for invalid flags on
1853                  * TUNSETIFF.
1854                  */
1855                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
1856                                 (unsigned int __user*)argp);
1857         } else if (cmd == TUNSETQUEUE)
1858                 return tun_set_queue(file, &ifr);
1859 
1860         ret = 0;
1861         rtnl_lock();
1862 
1863         tun = __tun_get(tfile);
1864         if (cmd == TUNSETIFF && !tun) {
1865                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1866 
1867                 ret = tun_set_iff(tfile->net, file, &ifr);
1868 
1869                 if (ret)
1870                         goto unlock;
1871 
1872                 if (copy_to_user(argp, &ifr, ifreq_len))
1873                         ret = -EFAULT;
1874                 goto unlock;
1875         }
1876         if (cmd == TUNSETIFINDEX) {
1877                 ret = -EPERM;
1878                 if (tun)
1879                         goto unlock;
1880 
1881                 ret = -EFAULT;
1882                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
1883                         goto unlock;
1884 
1885                 ret = 0;
1886                 tfile->ifindex = ifindex;
1887                 goto unlock;
1888         }
1889 
1890         ret = -EBADFD;
1891         if (!tun)
1892                 goto unlock;
1893 
1894         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1895 
1896         ret = 0;
1897         switch (cmd) {
1898         case TUNGETIFF:
1899                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1900 
1901                 if (tfile->detached)
1902                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
1903                 if (!tfile->socket.sk->sk_filter)
1904                         ifr.ifr_flags |= IFF_NOFILTER;
1905 
1906                 if (copy_to_user(argp, &ifr, ifreq_len))
1907                         ret = -EFAULT;
1908                 break;
1909 
1910         case TUNSETNOCSUM:
1911                 /* Disable/Enable checksum */
1912 
1913                 /* [unimplemented] */
1914                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1915                           arg ? "disabled" : "enabled");
1916                 break;
1917 
1918         case TUNSETPERSIST:
1919                 /* Disable/Enable persist mode. Keep an extra reference to the
1920                  * module to prevent the module being unprobed.
1921                  */
1922                 if (arg && !(tun->flags & IFF_PERSIST)) {
1923                         tun->flags |= IFF_PERSIST;
1924                         __module_get(THIS_MODULE);
1925                 }
1926                 if (!arg && (tun->flags & IFF_PERSIST)) {
1927                         tun->flags &= ~IFF_PERSIST;
1928                         module_put(THIS_MODULE);
1929                 }
1930 
1931                 tun_debug(KERN_INFO, tun, "persist %s\n",
1932                           arg ? "enabled" : "disabled");
1933                 break;
1934 
1935         case TUNSETOWNER:
1936                 /* Set owner of the device */
1937                 owner = make_kuid(current_user_ns(), arg);
1938                 if (!uid_valid(owner)) {
1939                         ret = -EINVAL;
1940                         break;
1941                 }
1942                 tun->owner = owner;
1943                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
1944                           from_kuid(&init_user_ns, tun->owner));
1945                 break;
1946 
1947         case TUNSETGROUP:
1948                 /* Set group of the device */
1949                 group = make_kgid(current_user_ns(), arg);
1950                 if (!gid_valid(group)) {
1951                         ret = -EINVAL;
1952                         break;
1953                 }
1954                 tun->group = group;
1955                 tun_debug(KERN_INFO, tun, "group set to %u\n",
1956                           from_kgid(&init_user_ns, tun->group));
1957                 break;
1958 
1959         case TUNSETLINK:
1960                 /* Only allow setting the type when the interface is down */
1961                 if (tun->dev->flags & IFF_UP) {
1962                         tun_debug(KERN_INFO, tun,
1963                                   "Linktype set failed because interface is up\n");
1964                         ret = -EBUSY;
1965                 } else {
1966                         tun->dev->type = (int) arg;
1967                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1968                                   tun->dev->type);
1969                         ret = 0;
1970                 }
1971                 break;
1972 
1973 #ifdef TUN_DEBUG
1974         case TUNSETDEBUG:
1975                 tun->debug = arg;
1976                 break;
1977 #endif
1978         case TUNSETOFFLOAD:
1979                 ret = set_offload(tun, arg);
1980                 break;
1981 
1982         case TUNSETTXFILTER:
1983                 /* Can be set only for TAPs */
1984                 ret = -EINVAL;
1985                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1986                         break;
1987                 ret = update_filter(&tun->txflt, (void __user *)arg);
1988                 break;
1989 
1990         case SIOCGIFHWADDR:
1991                 /* Get hw address */
1992                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1993                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1994                 if (copy_to_user(argp, &ifr, ifreq_len))
1995                         ret = -EFAULT;
1996                 break;
1997 
1998         case SIOCSIFHWADDR:
1999                 /* Set hw address */
2000                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2001                           ifr.ifr_hwaddr.sa_data);
2002 
2003                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2004                 break;
2005 
2006         case TUNGETSNDBUF:
2007                 sndbuf = tfile->socket.sk->sk_sndbuf;
2008                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2009                         ret = -EFAULT;
2010                 break;
2011 
2012         case TUNSETSNDBUF:
2013                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2014                         ret = -EFAULT;
2015                         break;
2016                 }
2017 
2018                 tun->sndbuf = sndbuf;
2019                 tun_set_sndbuf(tun);
2020                 break;
2021 
2022         case TUNGETVNETHDRSZ:
2023                 vnet_hdr_sz = tun->vnet_hdr_sz;
2024                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2025                         ret = -EFAULT;
2026                 break;
2027 
2028         case TUNSETVNETHDRSZ:
2029                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2030                         ret = -EFAULT;
2031                         break;
2032                 }
2033                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2034                         ret = -EINVAL;
2035                         break;
2036                 }
2037 
2038                 tun->vnet_hdr_sz = vnet_hdr_sz;
2039                 break;
2040 
2041         case TUNGETVNETLE:
2042                 le = !!(tun->flags & TUN_VNET_LE);
2043                 if (put_user(le, (int __user *)argp))
2044                         ret = -EFAULT;
2045                 break;
2046 
2047         case TUNSETVNETLE:
2048                 if (get_user(le, (int __user *)argp)) {
2049                         ret = -EFAULT;
2050                         break;
2051                 }
2052                 if (le)
2053                         tun->flags |= TUN_VNET_LE;
2054                 else
2055                         tun->flags &= ~TUN_VNET_LE;
2056                 break;
2057 
2058         case TUNATTACHFILTER:
2059                 /* Can be set only for TAPs */
2060                 ret = -EINVAL;
2061                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2062                         break;
2063                 ret = -EFAULT;
2064                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2065                         break;
2066 
2067                 ret = tun_attach_filter(tun);
2068                 break;
2069 
2070         case TUNDETACHFILTER:
2071                 /* Can be set only for TAPs */
2072                 ret = -EINVAL;
2073                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2074                         break;
2075                 ret = 0;
2076                 tun_detach_filter(tun, tun->numqueues);
2077                 break;
2078 
2079         case TUNGETFILTER:
2080                 ret = -EINVAL;
2081                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2082                         break;
2083                 ret = -EFAULT;
2084                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2085                         break;
2086                 ret = 0;
2087                 break;
2088 
2089         default:
2090                 ret = -EINVAL;
2091                 break;
2092         }
2093 
2094 unlock:
2095         rtnl_unlock();
2096         if (tun)
2097                 tun_put(tun);
2098         return ret;
2099 }
2100 
2101 static long tun_chr_ioctl(struct file *file,
2102                           unsigned int cmd, unsigned long arg)
2103 {
2104         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2105 }
2106 
2107 #ifdef CONFIG_COMPAT
2108 static long tun_chr_compat_ioctl(struct file *file,
2109                          unsigned int cmd, unsigned long arg)
2110 {
2111         switch (cmd) {
2112         case TUNSETIFF:
2113         case TUNGETIFF:
2114         case TUNSETTXFILTER:
2115         case TUNGETSNDBUF:
2116         case TUNSETSNDBUF:
2117         case SIOCGIFHWADDR:
2118         case SIOCSIFHWADDR:
2119                 arg = (unsigned long)compat_ptr(arg);
2120                 break;
2121         default:
2122                 arg = (compat_ulong_t)arg;
2123                 break;
2124         }
2125 
2126         /*
2127          * compat_ifreq is shorter than ifreq, so we must not access beyond
2128          * the end of that structure. All fields that are used in this
2129          * driver are compatible though, we don't need to convert the
2130          * contents.
2131          */
2132         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2133 }
2134 #endif /* CONFIG_COMPAT */
2135 
2136 static int tun_chr_fasync(int fd, struct file *file, int on)
2137 {
2138         struct tun_file *tfile = file->private_data;
2139         int ret;
2140 
2141         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2142                 goto out;
2143 
2144         if (on) {
2145                 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2146                 tfile->flags |= TUN_FASYNC;
2147         } else
2148                 tfile->flags &= ~TUN_FASYNC;
2149         ret = 0;
2150 out:
2151         return ret;
2152 }
2153 
2154 static int tun_chr_open(struct inode *inode, struct file * file)
2155 {
2156         struct tun_file *tfile;
2157 
2158         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2159 
2160         tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
2161                                             &tun_proto);
2162         if (!tfile)
2163                 return -ENOMEM;
2164         RCU_INIT_POINTER(tfile->tun, NULL);
2165         tfile->net = get_net(current->nsproxy->net_ns);
2166         tfile->flags = 0;
2167         tfile->ifindex = 0;
2168 
2169         init_waitqueue_head(&tfile->wq.wait);
2170         RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2171 
2172         tfile->socket.file = file;
2173         tfile->socket.ops = &tun_socket_ops;
2174 
2175         sock_init_data(&tfile->socket, &tfile->sk);
2176         sk_change_net(&tfile->sk, tfile->net);
2177 
2178         tfile->sk.sk_write_space = tun_sock_write_space;
2179         tfile->sk.sk_sndbuf = INT_MAX;
2180 
2181         file->private_data = tfile;
2182         set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
2183         INIT_LIST_HEAD(&tfile->next);
2184 
2185         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2186 
2187         return 0;
2188 }
2189 
2190 static int tun_chr_close(struct inode *inode, struct file *file)
2191 {
2192         struct tun_file *tfile = file->private_data;
2193         struct net *net = tfile->net;
2194 
2195         tun_detach(tfile, true);
2196         put_net(net);
2197 
2198         return 0;
2199 }
2200 
2201 #ifdef CONFIG_PROC_FS
2202 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2203 {
2204         struct tun_struct *tun;
2205         struct ifreq ifr;
2206 
2207         memset(&ifr, 0, sizeof(ifr));
2208 
2209         rtnl_lock();
2210         tun = tun_get(f);
2211         if (tun)
2212                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2213         rtnl_unlock();
2214 
2215         if (tun)
2216                 tun_put(tun);
2217 
2218         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2219 }
2220 #endif
2221 
2222 static const struct file_operations tun_fops = {
2223         .owner  = THIS_MODULE,
2224         .llseek = no_llseek,
2225         .read  = new_sync_read,
2226         .write = new_sync_write,
2227         .read_iter  = tun_chr_read_iter,
2228         .write_iter = tun_chr_write_iter,
2229         .poll   = tun_chr_poll,
2230         .unlocked_ioctl = tun_chr_ioctl,
2231 #ifdef CONFIG_COMPAT
2232         .compat_ioctl = tun_chr_compat_ioctl,
2233 #endif
2234         .open   = tun_chr_open,
2235         .release = tun_chr_close,
2236         .fasync = tun_chr_fasync,
2237 #ifdef CONFIG_PROC_FS
2238         .show_fdinfo = tun_chr_show_fdinfo,
2239 #endif
2240 };
2241 
2242 static struct miscdevice tun_miscdev = {
2243         .minor = TUN_MINOR,
2244         .name = "tun",
2245         .nodename = "net/tun",
2246         .fops = &tun_fops,
2247 };
2248 
2249 /* ethtool interface */
2250 
2251 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2252 {
2253         cmd->supported          = 0;
2254         cmd->advertising        = 0;
2255         ethtool_cmd_speed_set(cmd, SPEED_10);
2256         cmd->duplex             = DUPLEX_FULL;
2257         cmd->port               = PORT_TP;
2258         cmd->phy_address        = 0;
2259         cmd->transceiver        = XCVR_INTERNAL;
2260         cmd->autoneg            = AUTONEG_DISABLE;
2261         cmd->maxtxpkt           = 0;
2262         cmd->maxrxpkt           = 0;
2263         return 0;
2264 }
2265 
2266 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2267 {
2268         struct tun_struct *tun = netdev_priv(dev);
2269 
2270         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2271         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2272 
2273         switch (tun->flags & TUN_TYPE_MASK) {
2274         case IFF_TUN:
2275                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2276                 break;
2277         case IFF_TAP:
2278                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2279                 break;
2280         }
2281 }
2282 
2283 static u32 tun_get_msglevel(struct net_device *dev)
2284 {
2285 #ifdef TUN_DEBUG
2286         struct tun_struct *tun = netdev_priv(dev);
2287         return tun->debug;
2288 #else
2289         return -EOPNOTSUPP;
2290 #endif
2291 }
2292 
2293 static void tun_set_msglevel(struct net_device *dev, u32 value)
2294 {
2295 #ifdef TUN_DEBUG
2296         struct tun_struct *tun = netdev_priv(dev);
2297         tun->debug = value;
2298 #endif
2299 }
2300 
2301 static const struct ethtool_ops tun_ethtool_ops = {
2302         .get_settings   = tun_get_settings,
2303         .get_drvinfo    = tun_get_drvinfo,
2304         .get_msglevel   = tun_get_msglevel,
2305         .set_msglevel   = tun_set_msglevel,
2306         .get_link       = ethtool_op_get_link,
2307         .get_ts_info    = ethtool_op_get_ts_info,
2308 };
2309 
2310 
2311 static int __init tun_init(void)
2312 {
2313         int ret = 0;
2314 
2315         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2316         pr_info("%s\n", DRV_COPYRIGHT);
2317 
2318         ret = rtnl_link_register(&tun_link_ops);
2319         if (ret) {
2320                 pr_err("Can't register link_ops\n");
2321                 goto err_linkops;
2322         }
2323 
2324         ret = misc_register(&tun_miscdev);
2325         if (ret) {
2326                 pr_err("Can't register misc device %d\n", TUN_MINOR);
2327                 goto err_misc;
2328         }
2329         return  0;
2330 err_misc:
2331         rtnl_link_unregister(&tun_link_ops);
2332 err_linkops:
2333         return ret;
2334 }
2335 
2336 static void tun_cleanup(void)
2337 {
2338         misc_deregister(&tun_miscdev);
2339         rtnl_link_unregister(&tun_link_ops);
2340 }
2341 
2342 /* Get an underlying socket object from tun file.  Returns error unless file is
2343  * attached to a device.  The returned object works like a packet socket, it
2344  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2345  * holding a reference to the file for as long as the socket is in use. */
2346 struct socket *tun_get_socket(struct file *file)
2347 {
2348         struct tun_file *tfile;
2349         if (file->f_op != &tun_fops)
2350                 return ERR_PTR(-EINVAL);
2351         tfile = file->private_data;
2352         if (!tfile)
2353                 return ERR_PTR(-EBADFD);
2354         return &tfile->socket;
2355 }
2356 EXPORT_SYMBOL_GPL(tun_get_socket);
2357 
2358 module_init(tun_init);
2359 module_exit(tun_cleanup);
2360 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2361 MODULE_AUTHOR(DRV_COPYRIGHT);
2362 MODULE_LICENSE("GPL");
2363 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2364 MODULE_ALIAS("devname:net/tun");
2365 

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