Version:  2.0.40 2.2.26 2.4.37 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6

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 #define TUN_VNET_BE     0x40000000
115 
116 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
117                       IFF_MULTI_QUEUE)
118 #define GOODCOPY_LEN 128
119 
120 #define FLT_EXACT_COUNT 8
121 struct tap_filter {
122         unsigned int    count;    /* Number of addrs. Zero means disabled */
123         u32             mask[2];  /* Mask of the hashed addrs */
124         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
125 };
126 
127 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
128  * to max number of VCPUs in guest. */
129 #define MAX_TAP_QUEUES 256
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 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                     align;
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 #ifdef CONFIG_TUN_VNET_CROSS_LE
211 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
212 {
213         return tun->flags & TUN_VNET_BE ? false :
214                 virtio_legacy_is_little_endian();
215 }
216 
217 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
218 {
219         int be = !!(tun->flags & TUN_VNET_BE);
220 
221         if (put_user(be, argp))
222                 return -EFAULT;
223 
224         return 0;
225 }
226 
227 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
228 {
229         int be;
230 
231         if (get_user(be, argp))
232                 return -EFAULT;
233 
234         if (be)
235                 tun->flags |= TUN_VNET_BE;
236         else
237                 tun->flags &= ~TUN_VNET_BE;
238 
239         return 0;
240 }
241 #else
242 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
243 {
244         return virtio_legacy_is_little_endian();
245 }
246 
247 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
248 {
249         return -EINVAL;
250 }
251 
252 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
253 {
254         return -EINVAL;
255 }
256 #endif /* CONFIG_TUN_VNET_CROSS_LE */
257 
258 static inline bool tun_is_little_endian(struct tun_struct *tun)
259 {
260         return tun->flags & TUN_VNET_LE ||
261                 tun_legacy_is_little_endian(tun);
262 }
263 
264 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
265 {
266         return __virtio16_to_cpu(tun_is_little_endian(tun), val);
267 }
268 
269 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
270 {
271         return __cpu_to_virtio16(tun_is_little_endian(tun), val);
272 }
273 
274 static inline u32 tun_hashfn(u32 rxhash)
275 {
276         return rxhash & 0x3ff;
277 }
278 
279 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
280 {
281         struct tun_flow_entry *e;
282 
283         hlist_for_each_entry_rcu(e, head, hash_link) {
284                 if (e->rxhash == rxhash)
285                         return e;
286         }
287         return NULL;
288 }
289 
290 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
291                                               struct hlist_head *head,
292                                               u32 rxhash, u16 queue_index)
293 {
294         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
295 
296         if (e) {
297                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
298                           rxhash, queue_index);
299                 e->updated = jiffies;
300                 e->rxhash = rxhash;
301                 e->rps_rxhash = 0;
302                 e->queue_index = queue_index;
303                 e->tun = tun;
304                 hlist_add_head_rcu(&e->hash_link, head);
305                 ++tun->flow_count;
306         }
307         return e;
308 }
309 
310 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
311 {
312         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
313                   e->rxhash, e->queue_index);
314         hlist_del_rcu(&e->hash_link);
315         kfree_rcu(e, rcu);
316         --tun->flow_count;
317 }
318 
319 static void tun_flow_flush(struct tun_struct *tun)
320 {
321         int i;
322 
323         spin_lock_bh(&tun->lock);
324         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
325                 struct tun_flow_entry *e;
326                 struct hlist_node *n;
327 
328                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
329                         tun_flow_delete(tun, e);
330         }
331         spin_unlock_bh(&tun->lock);
332 }
333 
334 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
335 {
336         int i;
337 
338         spin_lock_bh(&tun->lock);
339         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
340                 struct tun_flow_entry *e;
341                 struct hlist_node *n;
342 
343                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
344                         if (e->queue_index == queue_index)
345                                 tun_flow_delete(tun, e);
346                 }
347         }
348         spin_unlock_bh(&tun->lock);
349 }
350 
351 static void tun_flow_cleanup(unsigned long data)
352 {
353         struct tun_struct *tun = (struct tun_struct *)data;
354         unsigned long delay = tun->ageing_time;
355         unsigned long next_timer = jiffies + delay;
356         unsigned long count = 0;
357         int i;
358 
359         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
360 
361         spin_lock_bh(&tun->lock);
362         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
363                 struct tun_flow_entry *e;
364                 struct hlist_node *n;
365 
366                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
367                         unsigned long this_timer;
368                         count++;
369                         this_timer = e->updated + delay;
370                         if (time_before_eq(this_timer, jiffies))
371                                 tun_flow_delete(tun, e);
372                         else if (time_before(this_timer, next_timer))
373                                 next_timer = this_timer;
374                 }
375         }
376 
377         if (count)
378                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
379         spin_unlock_bh(&tun->lock);
380 }
381 
382 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
383                             struct tun_file *tfile)
384 {
385         struct hlist_head *head;
386         struct tun_flow_entry *e;
387         unsigned long delay = tun->ageing_time;
388         u16 queue_index = tfile->queue_index;
389 
390         if (!rxhash)
391                 return;
392         else
393                 head = &tun->flows[tun_hashfn(rxhash)];
394 
395         rcu_read_lock();
396 
397         /* We may get a very small possibility of OOO during switching, not
398          * worth to optimize.*/
399         if (tun->numqueues == 1 || tfile->detached)
400                 goto unlock;
401 
402         e = tun_flow_find(head, rxhash);
403         if (likely(e)) {
404                 /* TODO: keep queueing to old queue until it's empty? */
405                 e->queue_index = queue_index;
406                 e->updated = jiffies;
407                 sock_rps_record_flow_hash(e->rps_rxhash);
408         } else {
409                 spin_lock_bh(&tun->lock);
410                 if (!tun_flow_find(head, rxhash) &&
411                     tun->flow_count < MAX_TAP_FLOWS)
412                         tun_flow_create(tun, head, rxhash, queue_index);
413 
414                 if (!timer_pending(&tun->flow_gc_timer))
415                         mod_timer(&tun->flow_gc_timer,
416                                   round_jiffies_up(jiffies + delay));
417                 spin_unlock_bh(&tun->lock);
418         }
419 
420 unlock:
421         rcu_read_unlock();
422 }
423 
424 /**
425  * Save the hash received in the stack receive path and update the
426  * flow_hash table accordingly.
427  */
428 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
429 {
430         if (unlikely(e->rps_rxhash != hash))
431                 e->rps_rxhash = hash;
432 }
433 
434 /* We try to identify a flow through its rxhash first. The reason that
435  * we do not check rxq no. is because some cards(e.g 82599), chooses
436  * the rxq based on the txq where the last packet of the flow comes. As
437  * the userspace application move between processors, we may get a
438  * different rxq no. here. If we could not get rxhash, then we would
439  * hope the rxq no. may help here.
440  */
441 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
442                             void *accel_priv, select_queue_fallback_t fallback)
443 {
444         struct tun_struct *tun = netdev_priv(dev);
445         struct tun_flow_entry *e;
446         u32 txq = 0;
447         u32 numqueues = 0;
448 
449         rcu_read_lock();
450         numqueues = ACCESS_ONCE(tun->numqueues);
451 
452         txq = skb_get_hash(skb);
453         if (txq) {
454                 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
455                 if (e) {
456                         tun_flow_save_rps_rxhash(e, txq);
457                         txq = e->queue_index;
458                 } else
459                         /* use multiply and shift instead of expensive divide */
460                         txq = ((u64)txq * numqueues) >> 32;
461         } else if (likely(skb_rx_queue_recorded(skb))) {
462                 txq = skb_get_rx_queue(skb);
463                 while (unlikely(txq >= numqueues))
464                         txq -= numqueues;
465         }
466 
467         rcu_read_unlock();
468         return txq;
469 }
470 
471 static inline bool tun_not_capable(struct tun_struct *tun)
472 {
473         const struct cred *cred = current_cred();
474         struct net *net = dev_net(tun->dev);
475 
476         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
477                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
478                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
479 }
480 
481 static void tun_set_real_num_queues(struct tun_struct *tun)
482 {
483         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
484         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
485 }
486 
487 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
488 {
489         tfile->detached = tun;
490         list_add_tail(&tfile->next, &tun->disabled);
491         ++tun->numdisabled;
492 }
493 
494 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
495 {
496         struct tun_struct *tun = tfile->detached;
497 
498         tfile->detached = NULL;
499         list_del_init(&tfile->next);
500         --tun->numdisabled;
501         return tun;
502 }
503 
504 static void tun_queue_purge(struct tun_file *tfile)
505 {
506         skb_queue_purge(&tfile->sk.sk_receive_queue);
507         skb_queue_purge(&tfile->sk.sk_error_queue);
508 }
509 
510 static void __tun_detach(struct tun_file *tfile, bool clean)
511 {
512         struct tun_file *ntfile;
513         struct tun_struct *tun;
514 
515         tun = rtnl_dereference(tfile->tun);
516 
517         if (tun && !tfile->detached) {
518                 u16 index = tfile->queue_index;
519                 BUG_ON(index >= tun->numqueues);
520 
521                 rcu_assign_pointer(tun->tfiles[index],
522                                    tun->tfiles[tun->numqueues - 1]);
523                 ntfile = rtnl_dereference(tun->tfiles[index]);
524                 ntfile->queue_index = index;
525 
526                 --tun->numqueues;
527                 if (clean) {
528                         RCU_INIT_POINTER(tfile->tun, NULL);
529                         sock_put(&tfile->sk);
530                 } else
531                         tun_disable_queue(tun, tfile);
532 
533                 synchronize_net();
534                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
535                 /* Drop read queue */
536                 tun_queue_purge(tfile);
537                 tun_set_real_num_queues(tun);
538         } else if (tfile->detached && clean) {
539                 tun = tun_enable_queue(tfile);
540                 sock_put(&tfile->sk);
541         }
542 
543         if (clean) {
544                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
545                         netif_carrier_off(tun->dev);
546 
547                         if (!(tun->flags & IFF_PERSIST) &&
548                             tun->dev->reg_state == NETREG_REGISTERED)
549                                 unregister_netdevice(tun->dev);
550                 }
551                 sock_put(&tfile->sk);
552         }
553 }
554 
555 static void tun_detach(struct tun_file *tfile, bool clean)
556 {
557         rtnl_lock();
558         __tun_detach(tfile, clean);
559         rtnl_unlock();
560 }
561 
562 static void tun_detach_all(struct net_device *dev)
563 {
564         struct tun_struct *tun = netdev_priv(dev);
565         struct tun_file *tfile, *tmp;
566         int i, n = tun->numqueues;
567 
568         for (i = 0; i < n; i++) {
569                 tfile = rtnl_dereference(tun->tfiles[i]);
570                 BUG_ON(!tfile);
571                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
572                 RCU_INIT_POINTER(tfile->tun, NULL);
573                 --tun->numqueues;
574         }
575         list_for_each_entry(tfile, &tun->disabled, next) {
576                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
577                 RCU_INIT_POINTER(tfile->tun, NULL);
578         }
579         BUG_ON(tun->numqueues != 0);
580 
581         synchronize_net();
582         for (i = 0; i < n; i++) {
583                 tfile = rtnl_dereference(tun->tfiles[i]);
584                 /* Drop read queue */
585                 tun_queue_purge(tfile);
586                 sock_put(&tfile->sk);
587         }
588         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
589                 tun_enable_queue(tfile);
590                 tun_queue_purge(tfile);
591                 sock_put(&tfile->sk);
592         }
593         BUG_ON(tun->numdisabled != 0);
594 
595         if (tun->flags & IFF_PERSIST)
596                 module_put(THIS_MODULE);
597 }
598 
599 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
600 {
601         struct tun_file *tfile = file->private_data;
602         int err;
603 
604         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
605         if (err < 0)
606                 goto out;
607 
608         err = -EINVAL;
609         if (rtnl_dereference(tfile->tun) && !tfile->detached)
610                 goto out;
611 
612         err = -EBUSY;
613         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
614                 goto out;
615 
616         err = -E2BIG;
617         if (!tfile->detached &&
618             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
619                 goto out;
620 
621         err = 0;
622 
623         /* Re-attach the filter to persist device */
624         if (!skip_filter && (tun->filter_attached == true)) {
625                 err = __sk_attach_filter(&tun->fprog, tfile->socket.sk,
626                                          lockdep_rtnl_is_held());
627                 if (!err)
628                         goto out;
629         }
630         tfile->queue_index = tun->numqueues;
631         rcu_assign_pointer(tfile->tun, tun);
632         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
633         tun->numqueues++;
634 
635         if (tfile->detached)
636                 tun_enable_queue(tfile);
637         else
638                 sock_hold(&tfile->sk);
639 
640         tun_set_real_num_queues(tun);
641 
642         /* device is allowed to go away first, so no need to hold extra
643          * refcnt.
644          */
645 
646 out:
647         return err;
648 }
649 
650 static struct tun_struct *__tun_get(struct tun_file *tfile)
651 {
652         struct tun_struct *tun;
653 
654         rcu_read_lock();
655         tun = rcu_dereference(tfile->tun);
656         if (tun)
657                 dev_hold(tun->dev);
658         rcu_read_unlock();
659 
660         return tun;
661 }
662 
663 static struct tun_struct *tun_get(struct file *file)
664 {
665         return __tun_get(file->private_data);
666 }
667 
668 static void tun_put(struct tun_struct *tun)
669 {
670         dev_put(tun->dev);
671 }
672 
673 /* TAP filtering */
674 static void addr_hash_set(u32 *mask, const u8 *addr)
675 {
676         int n = ether_crc(ETH_ALEN, addr) >> 26;
677         mask[n >> 5] |= (1 << (n & 31));
678 }
679 
680 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
681 {
682         int n = ether_crc(ETH_ALEN, addr) >> 26;
683         return mask[n >> 5] & (1 << (n & 31));
684 }
685 
686 static int update_filter(struct tap_filter *filter, void __user *arg)
687 {
688         struct { u8 u[ETH_ALEN]; } *addr;
689         struct tun_filter uf;
690         int err, alen, n, nexact;
691 
692         if (copy_from_user(&uf, arg, sizeof(uf)))
693                 return -EFAULT;
694 
695         if (!uf.count) {
696                 /* Disabled */
697                 filter->count = 0;
698                 return 0;
699         }
700 
701         alen = ETH_ALEN * uf.count;
702         addr = kmalloc(alen, GFP_KERNEL);
703         if (!addr)
704                 return -ENOMEM;
705 
706         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
707                 err = -EFAULT;
708                 goto done;
709         }
710 
711         /* The filter is updated without holding any locks. Which is
712          * perfectly safe. We disable it first and in the worst
713          * case we'll accept a few undesired packets. */
714         filter->count = 0;
715         wmb();
716 
717         /* Use first set of addresses as an exact filter */
718         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
719                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
720 
721         nexact = n;
722 
723         /* Remaining multicast addresses are hashed,
724          * unicast will leave the filter disabled. */
725         memset(filter->mask, 0, sizeof(filter->mask));
726         for (; n < uf.count; n++) {
727                 if (!is_multicast_ether_addr(addr[n].u)) {
728                         err = 0; /* no filter */
729                         goto done;
730                 }
731                 addr_hash_set(filter->mask, addr[n].u);
732         }
733 
734         /* For ALLMULTI just set the mask to all ones.
735          * This overrides the mask populated above. */
736         if ((uf.flags & TUN_FLT_ALLMULTI))
737                 memset(filter->mask, ~0, sizeof(filter->mask));
738 
739         /* Now enable the filter */
740         wmb();
741         filter->count = nexact;
742 
743         /* Return the number of exact filters */
744         err = nexact;
745 
746 done:
747         kfree(addr);
748         return err;
749 }
750 
751 /* Returns: 0 - drop, !=0 - accept */
752 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
753 {
754         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
755          * at this point. */
756         struct ethhdr *eh = (struct ethhdr *) skb->data;
757         int i;
758 
759         /* Exact match */
760         for (i = 0; i < filter->count; i++)
761                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
762                         return 1;
763 
764         /* Inexact match (multicast only) */
765         if (is_multicast_ether_addr(eh->h_dest))
766                 return addr_hash_test(filter->mask, eh->h_dest);
767 
768         return 0;
769 }
770 
771 /*
772  * Checks whether the packet is accepted or not.
773  * Returns: 0 - drop, !=0 - accept
774  */
775 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
776 {
777         if (!filter->count)
778                 return 1;
779 
780         return run_filter(filter, skb);
781 }
782 
783 /* Network device part of the driver */
784 
785 static const struct ethtool_ops tun_ethtool_ops;
786 
787 /* Net device detach from fd. */
788 static void tun_net_uninit(struct net_device *dev)
789 {
790         tun_detach_all(dev);
791 }
792 
793 /* Net device open. */
794 static int tun_net_open(struct net_device *dev)
795 {
796         netif_tx_start_all_queues(dev);
797         return 0;
798 }
799 
800 /* Net device close. */
801 static int tun_net_close(struct net_device *dev)
802 {
803         netif_tx_stop_all_queues(dev);
804         return 0;
805 }
806 
807 /* Net device start xmit */
808 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
809 {
810         struct tun_struct *tun = netdev_priv(dev);
811         int txq = skb->queue_mapping;
812         struct tun_file *tfile;
813         u32 numqueues = 0;
814 
815         rcu_read_lock();
816         tfile = rcu_dereference(tun->tfiles[txq]);
817         numqueues = ACCESS_ONCE(tun->numqueues);
818 
819         /* Drop packet if interface is not attached */
820         if (txq >= numqueues)
821                 goto drop;
822 
823         if (numqueues == 1) {
824                 /* Select queue was not called for the skbuff, so we extract the
825                  * RPS hash and save it into the flow_table here.
826                  */
827                 __u32 rxhash;
828 
829                 rxhash = skb_get_hash(skb);
830                 if (rxhash) {
831                         struct tun_flow_entry *e;
832                         e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
833                                         rxhash);
834                         if (e)
835                                 tun_flow_save_rps_rxhash(e, rxhash);
836                 }
837         }
838 
839         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
840 
841         BUG_ON(!tfile);
842 
843         /* Drop if the filter does not like it.
844          * This is a noop if the filter is disabled.
845          * Filter can be enabled only for the TAP devices. */
846         if (!check_filter(&tun->txflt, skb))
847                 goto drop;
848 
849         if (tfile->socket.sk->sk_filter &&
850             sk_filter(tfile->socket.sk, skb))
851                 goto drop;
852 
853         /* Limit the number of packets queued by dividing txq length with the
854          * number of queues.
855          */
856         if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues
857                           >= dev->tx_queue_len)
858                 goto drop;
859 
860         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
861                 goto drop;
862 
863         if (skb->sk && sk_fullsock(skb->sk)) {
864                 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags);
865                 sw_tx_timestamp(skb);
866         }
867 
868         /* Orphan the skb - required as we might hang on to it
869          * for indefinite time.
870          */
871         skb_orphan(skb);
872 
873         nf_reset(skb);
874 
875         /* Enqueue packet */
876         skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
877 
878         /* Notify and wake up reader process */
879         if (tfile->flags & TUN_FASYNC)
880                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
881         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
882 
883         rcu_read_unlock();
884         return NETDEV_TX_OK;
885 
886 drop:
887         dev->stats.tx_dropped++;
888         skb_tx_error(skb);
889         kfree_skb(skb);
890         rcu_read_unlock();
891         return NET_XMIT_DROP;
892 }
893 
894 static void tun_net_mclist(struct net_device *dev)
895 {
896         /*
897          * This callback is supposed to deal with mc filter in
898          * _rx_ path and has nothing to do with the _tx_ path.
899          * In rx path we always accept everything userspace gives us.
900          */
901 }
902 
903 #define MIN_MTU 68
904 #define MAX_MTU 65535
905 
906 static int
907 tun_net_change_mtu(struct net_device *dev, int new_mtu)
908 {
909         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
910                 return -EINVAL;
911         dev->mtu = new_mtu;
912         return 0;
913 }
914 
915 static netdev_features_t tun_net_fix_features(struct net_device *dev,
916         netdev_features_t features)
917 {
918         struct tun_struct *tun = netdev_priv(dev);
919 
920         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
921 }
922 #ifdef CONFIG_NET_POLL_CONTROLLER
923 static void tun_poll_controller(struct net_device *dev)
924 {
925         /*
926          * Tun only receives frames when:
927          * 1) the char device endpoint gets data from user space
928          * 2) the tun socket gets a sendmsg call from user space
929          * Since both of those are synchronous operations, we are guaranteed
930          * never to have pending data when we poll for it
931          * so there is nothing to do here but return.
932          * We need this though so netpoll recognizes us as an interface that
933          * supports polling, which enables bridge devices in virt setups to
934          * still use netconsole
935          */
936         return;
937 }
938 #endif
939 
940 static void tun_set_headroom(struct net_device *dev, int new_hr)
941 {
942         struct tun_struct *tun = netdev_priv(dev);
943 
944         if (new_hr < NET_SKB_PAD)
945                 new_hr = NET_SKB_PAD;
946 
947         tun->align = new_hr;
948 }
949 
950 static const struct net_device_ops tun_netdev_ops = {
951         .ndo_uninit             = tun_net_uninit,
952         .ndo_open               = tun_net_open,
953         .ndo_stop               = tun_net_close,
954         .ndo_start_xmit         = tun_net_xmit,
955         .ndo_change_mtu         = tun_net_change_mtu,
956         .ndo_fix_features       = tun_net_fix_features,
957         .ndo_select_queue       = tun_select_queue,
958 #ifdef CONFIG_NET_POLL_CONTROLLER
959         .ndo_poll_controller    = tun_poll_controller,
960 #endif
961         .ndo_set_rx_headroom    = tun_set_headroom,
962 };
963 
964 static const struct net_device_ops tap_netdev_ops = {
965         .ndo_uninit             = tun_net_uninit,
966         .ndo_open               = tun_net_open,
967         .ndo_stop               = tun_net_close,
968         .ndo_start_xmit         = tun_net_xmit,
969         .ndo_change_mtu         = tun_net_change_mtu,
970         .ndo_fix_features       = tun_net_fix_features,
971         .ndo_set_rx_mode        = tun_net_mclist,
972         .ndo_set_mac_address    = eth_mac_addr,
973         .ndo_validate_addr      = eth_validate_addr,
974         .ndo_select_queue       = tun_select_queue,
975 #ifdef CONFIG_NET_POLL_CONTROLLER
976         .ndo_poll_controller    = tun_poll_controller,
977 #endif
978         .ndo_features_check     = passthru_features_check,
979         .ndo_set_rx_headroom    = tun_set_headroom,
980 };
981 
982 static void tun_flow_init(struct tun_struct *tun)
983 {
984         int i;
985 
986         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
987                 INIT_HLIST_HEAD(&tun->flows[i]);
988 
989         tun->ageing_time = TUN_FLOW_EXPIRE;
990         setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
991         mod_timer(&tun->flow_gc_timer,
992                   round_jiffies_up(jiffies + tun->ageing_time));
993 }
994 
995 static void tun_flow_uninit(struct tun_struct *tun)
996 {
997         del_timer_sync(&tun->flow_gc_timer);
998         tun_flow_flush(tun);
999 }
1000 
1001 /* Initialize net device. */
1002 static void tun_net_init(struct net_device *dev)
1003 {
1004         struct tun_struct *tun = netdev_priv(dev);
1005 
1006         switch (tun->flags & TUN_TYPE_MASK) {
1007         case IFF_TUN:
1008                 dev->netdev_ops = &tun_netdev_ops;
1009 
1010                 /* Point-to-Point TUN Device */
1011                 dev->hard_header_len = 0;
1012                 dev->addr_len = 0;
1013                 dev->mtu = 1500;
1014 
1015                 /* Zero header length */
1016                 dev->type = ARPHRD_NONE;
1017                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1018                 break;
1019 
1020         case IFF_TAP:
1021                 dev->netdev_ops = &tap_netdev_ops;
1022                 /* Ethernet TAP Device */
1023                 ether_setup(dev);
1024                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1025                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1026 
1027                 eth_hw_addr_random(dev);
1028 
1029                 break;
1030         }
1031 }
1032 
1033 /* Character device part */
1034 
1035 /* Poll */
1036 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1037 {
1038         struct tun_file *tfile = file->private_data;
1039         struct tun_struct *tun = __tun_get(tfile);
1040         struct sock *sk;
1041         unsigned int mask = 0;
1042 
1043         if (!tun)
1044                 return POLLERR;
1045 
1046         sk = tfile->socket.sk;
1047 
1048         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1049 
1050         poll_wait(file, sk_sleep(sk), wait);
1051 
1052         if (!skb_queue_empty(&sk->sk_receive_queue))
1053                 mask |= POLLIN | POLLRDNORM;
1054 
1055         if (sock_writeable(sk) ||
1056             (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1057              sock_writeable(sk)))
1058                 mask |= POLLOUT | POLLWRNORM;
1059 
1060         if (tun->dev->reg_state != NETREG_REGISTERED)
1061                 mask = POLLERR;
1062 
1063         tun_put(tun);
1064         return mask;
1065 }
1066 
1067 /* prepad is the amount to reserve at front.  len is length after that.
1068  * linear is a hint as to how much to copy (usually headers). */
1069 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1070                                      size_t prepad, size_t len,
1071                                      size_t linear, int noblock)
1072 {
1073         struct sock *sk = tfile->socket.sk;
1074         struct sk_buff *skb;
1075         int err;
1076 
1077         /* Under a page?  Don't bother with paged skb. */
1078         if (prepad + len < PAGE_SIZE || !linear)
1079                 linear = len;
1080 
1081         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1082                                    &err, 0);
1083         if (!skb)
1084                 return ERR_PTR(err);
1085 
1086         skb_reserve(skb, prepad);
1087         skb_put(skb, linear);
1088         skb->data_len = len - linear;
1089         skb->len += len - linear;
1090 
1091         return skb;
1092 }
1093 
1094 /* Get packet from user space buffer */
1095 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1096                             void *msg_control, struct iov_iter *from,
1097                             int noblock)
1098 {
1099         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1100         struct sk_buff *skb;
1101         size_t total_len = iov_iter_count(from);
1102         size_t len = total_len, align = tun->align, linear;
1103         struct virtio_net_hdr gso = { 0 };
1104         int good_linear;
1105         int copylen;
1106         bool zerocopy = false;
1107         int err;
1108         u32 rxhash;
1109         ssize_t n;
1110 
1111         if (!(tun->dev->flags & IFF_UP))
1112                 return -EIO;
1113 
1114         if (!(tun->flags & IFF_NO_PI)) {
1115                 if (len < sizeof(pi))
1116                         return -EINVAL;
1117                 len -= sizeof(pi);
1118 
1119                 n = copy_from_iter(&pi, sizeof(pi), from);
1120                 if (n != sizeof(pi))
1121                         return -EFAULT;
1122         }
1123 
1124         if (tun->flags & IFF_VNET_HDR) {
1125                 if (len < tun->vnet_hdr_sz)
1126                         return -EINVAL;
1127                 len -= tun->vnet_hdr_sz;
1128 
1129                 n = copy_from_iter(&gso, sizeof(gso), from);
1130                 if (n != sizeof(gso))
1131                         return -EFAULT;
1132 
1133                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1134                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1135                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1136 
1137                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1138                         return -EINVAL;
1139                 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso));
1140         }
1141 
1142         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1143                 align += NET_IP_ALIGN;
1144                 if (unlikely(len < ETH_HLEN ||
1145                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1146                         return -EINVAL;
1147         }
1148 
1149         good_linear = SKB_MAX_HEAD(align);
1150 
1151         if (msg_control) {
1152                 struct iov_iter i = *from;
1153 
1154                 /* There are 256 bytes to be copied in skb, so there is
1155                  * enough room for skb expand head in case it is used.
1156                  * The rest of the buffer is mapped from userspace.
1157                  */
1158                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1159                 if (copylen > good_linear)
1160                         copylen = good_linear;
1161                 linear = copylen;
1162                 iov_iter_advance(&i, copylen);
1163                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1164                         zerocopy = true;
1165         }
1166 
1167         if (!zerocopy) {
1168                 copylen = len;
1169                 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1170                         linear = good_linear;
1171                 else
1172                         linear = tun16_to_cpu(tun, gso.hdr_len);
1173         }
1174 
1175         skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1176         if (IS_ERR(skb)) {
1177                 if (PTR_ERR(skb) != -EAGAIN)
1178                         tun->dev->stats.rx_dropped++;
1179                 return PTR_ERR(skb);
1180         }
1181 
1182         if (zerocopy)
1183                 err = zerocopy_sg_from_iter(skb, from);
1184         else {
1185                 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1186                 if (!err && msg_control) {
1187                         struct ubuf_info *uarg = msg_control;
1188                         uarg->callback(uarg, false);
1189                 }
1190         }
1191 
1192         if (err) {
1193                 tun->dev->stats.rx_dropped++;
1194                 kfree_skb(skb);
1195                 return -EFAULT;
1196         }
1197 
1198         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1199                 if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start),
1200                                           tun16_to_cpu(tun, gso.csum_offset))) {
1201                         tun->dev->stats.rx_frame_errors++;
1202                         kfree_skb(skb);
1203                         return -EINVAL;
1204                 }
1205         }
1206 
1207         switch (tun->flags & TUN_TYPE_MASK) {
1208         case IFF_TUN:
1209                 if (tun->flags & IFF_NO_PI) {
1210                         switch (skb->data[0] & 0xf0) {
1211                         case 0x40:
1212                                 pi.proto = htons(ETH_P_IP);
1213                                 break;
1214                         case 0x60:
1215                                 pi.proto = htons(ETH_P_IPV6);
1216                                 break;
1217                         default:
1218                                 tun->dev->stats.rx_dropped++;
1219                                 kfree_skb(skb);
1220                                 return -EINVAL;
1221                         }
1222                 }
1223 
1224                 skb_reset_mac_header(skb);
1225                 skb->protocol = pi.proto;
1226                 skb->dev = tun->dev;
1227                 break;
1228         case IFF_TAP:
1229                 skb->protocol = eth_type_trans(skb, tun->dev);
1230                 break;
1231         }
1232 
1233         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1234                 pr_debug("GSO!\n");
1235                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1236                 case VIRTIO_NET_HDR_GSO_TCPV4:
1237                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1238                         break;
1239                 case VIRTIO_NET_HDR_GSO_TCPV6:
1240                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1241                         break;
1242                 case VIRTIO_NET_HDR_GSO_UDP:
1243                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1244                         break;
1245                 default:
1246                         tun->dev->stats.rx_frame_errors++;
1247                         kfree_skb(skb);
1248                         return -EINVAL;
1249                 }
1250 
1251                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1252                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1253 
1254                 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size);
1255                 if (skb_shinfo(skb)->gso_size == 0) {
1256                         tun->dev->stats.rx_frame_errors++;
1257                         kfree_skb(skb);
1258                         return -EINVAL;
1259                 }
1260 
1261                 /* Header must be checked, and gso_segs computed. */
1262                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1263                 skb_shinfo(skb)->gso_segs = 0;
1264         }
1265 
1266         /* copy skb_ubuf_info for callback when skb has no error */
1267         if (zerocopy) {
1268                 skb_shinfo(skb)->destructor_arg = msg_control;
1269                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1270                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1271         }
1272 
1273         skb_reset_network_header(skb);
1274         skb_probe_transport_header(skb, 0);
1275 
1276         rxhash = skb_get_hash(skb);
1277         netif_rx_ni(skb);
1278 
1279         tun->dev->stats.rx_packets++;
1280         tun->dev->stats.rx_bytes += len;
1281 
1282         tun_flow_update(tun, rxhash, tfile);
1283         return total_len;
1284 }
1285 
1286 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1287 {
1288         struct file *file = iocb->ki_filp;
1289         struct tun_struct *tun = tun_get(file);
1290         struct tun_file *tfile = file->private_data;
1291         ssize_t result;
1292 
1293         if (!tun)
1294                 return -EBADFD;
1295 
1296         result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);
1297 
1298         tun_put(tun);
1299         return result;
1300 }
1301 
1302 /* Put packet to the user space buffer */
1303 static ssize_t tun_put_user(struct tun_struct *tun,
1304                             struct tun_file *tfile,
1305                             struct sk_buff *skb,
1306                             struct iov_iter *iter)
1307 {
1308         struct tun_pi pi = { 0, skb->protocol };
1309         ssize_t total;
1310         int vlan_offset = 0;
1311         int vlan_hlen = 0;
1312         int vnet_hdr_sz = 0;
1313 
1314         if (skb_vlan_tag_present(skb))
1315                 vlan_hlen = VLAN_HLEN;
1316 
1317         if (tun->flags & IFF_VNET_HDR)
1318                 vnet_hdr_sz = tun->vnet_hdr_sz;
1319 
1320         total = skb->len + vlan_hlen + vnet_hdr_sz;
1321 
1322         if (!(tun->flags & IFF_NO_PI)) {
1323                 if (iov_iter_count(iter) < sizeof(pi))
1324                         return -EINVAL;
1325 
1326                 total += sizeof(pi);
1327                 if (iov_iter_count(iter) < total) {
1328                         /* Packet will be striped */
1329                         pi.flags |= TUN_PKT_STRIP;
1330                 }
1331 
1332                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1333                         return -EFAULT;
1334         }
1335 
1336         if (vnet_hdr_sz) {
1337                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1338                 if (iov_iter_count(iter) < vnet_hdr_sz)
1339                         return -EINVAL;
1340 
1341                 if (skb_is_gso(skb)) {
1342                         struct skb_shared_info *sinfo = skb_shinfo(skb);
1343 
1344                         /* This is a hint as to how much should be linear. */
1345                         gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb));
1346                         gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size);
1347                         if (sinfo->gso_type & SKB_GSO_TCPV4)
1348                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1349                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
1350                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1351                         else if (sinfo->gso_type & SKB_GSO_UDP)
1352                                 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1353                         else {
1354                                 pr_err("unexpected GSO type: "
1355                                        "0x%x, gso_size %d, hdr_len %d\n",
1356                                        sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1357                                        tun16_to_cpu(tun, gso.hdr_len));
1358                                 print_hex_dump(KERN_ERR, "tun: ",
1359                                                DUMP_PREFIX_NONE,
1360                                                16, 1, skb->head,
1361                                                min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1362                                 WARN_ON_ONCE(1);
1363                                 return -EINVAL;
1364                         }
1365                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1366                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1367                 } else
1368                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1369 
1370                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1371                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1372                         gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) +
1373                                                       vlan_hlen);
1374                         gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset);
1375                 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1376                         gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1377                 } /* else everything is zero */
1378 
1379                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1380                         return -EFAULT;
1381 
1382                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1383         }
1384 
1385         if (vlan_hlen) {
1386                 int ret;
1387                 struct {
1388                         __be16 h_vlan_proto;
1389                         __be16 h_vlan_TCI;
1390                 } veth;
1391 
1392                 veth.h_vlan_proto = skb->vlan_proto;
1393                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1394 
1395                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1396 
1397                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1398                 if (ret || !iov_iter_count(iter))
1399                         goto done;
1400 
1401                 ret = copy_to_iter(&veth, sizeof(veth), iter);
1402                 if (ret != sizeof(veth) || !iov_iter_count(iter))
1403                         goto done;
1404         }
1405 
1406         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1407 
1408 done:
1409         tun->dev->stats.tx_packets++;
1410         tun->dev->stats.tx_bytes += skb->len + vlan_hlen;
1411 
1412         return total;
1413 }
1414 
1415 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1416                            struct iov_iter *to,
1417                            int noblock)
1418 {
1419         struct sk_buff *skb;
1420         ssize_t ret;
1421         int peeked, err, off = 0;
1422 
1423         tun_debug(KERN_INFO, tun, "tun_do_read\n");
1424 
1425         if (!iov_iter_count(to))
1426                 return 0;
1427 
1428         if (tun->dev->reg_state != NETREG_REGISTERED)
1429                 return -EIO;
1430 
1431         /* Read frames from queue */
1432         skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0,
1433                                   &peeked, &off, &err);
1434         if (!skb)
1435                 return err;
1436 
1437         ret = tun_put_user(tun, tfile, skb, to);
1438         if (unlikely(ret < 0))
1439                 kfree_skb(skb);
1440         else
1441                 consume_skb(skb);
1442 
1443         return ret;
1444 }
1445 
1446 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1447 {
1448         struct file *file = iocb->ki_filp;
1449         struct tun_file *tfile = file->private_data;
1450         struct tun_struct *tun = __tun_get(tfile);
1451         ssize_t len = iov_iter_count(to), ret;
1452 
1453         if (!tun)
1454                 return -EBADFD;
1455         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
1456         ret = min_t(ssize_t, ret, len);
1457         if (ret > 0)
1458                 iocb->ki_pos = ret;
1459         tun_put(tun);
1460         return ret;
1461 }
1462 
1463 static void tun_free_netdev(struct net_device *dev)
1464 {
1465         struct tun_struct *tun = netdev_priv(dev);
1466 
1467         BUG_ON(!(list_empty(&tun->disabled)));
1468         tun_flow_uninit(tun);
1469         security_tun_dev_free_security(tun->security);
1470         free_netdev(dev);
1471 }
1472 
1473 static void tun_setup(struct net_device *dev)
1474 {
1475         struct tun_struct *tun = netdev_priv(dev);
1476 
1477         tun->owner = INVALID_UID;
1478         tun->group = INVALID_GID;
1479 
1480         dev->ethtool_ops = &tun_ethtool_ops;
1481         dev->destructor = tun_free_netdev;
1482         /* We prefer our own queue length */
1483         dev->tx_queue_len = TUN_READQ_SIZE;
1484 }
1485 
1486 /* Trivial set of netlink ops to allow deleting tun or tap
1487  * device with netlink.
1488  */
1489 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1490 {
1491         return -EINVAL;
1492 }
1493 
1494 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1495         .kind           = DRV_NAME,
1496         .priv_size      = sizeof(struct tun_struct),
1497         .setup          = tun_setup,
1498         .validate       = tun_validate,
1499 };
1500 
1501 static void tun_sock_write_space(struct sock *sk)
1502 {
1503         struct tun_file *tfile;
1504         wait_queue_head_t *wqueue;
1505 
1506         if (!sock_writeable(sk))
1507                 return;
1508 
1509         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
1510                 return;
1511 
1512         wqueue = sk_sleep(sk);
1513         if (wqueue && waitqueue_active(wqueue))
1514                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1515                                                 POLLWRNORM | POLLWRBAND);
1516 
1517         tfile = container_of(sk, struct tun_file, sk);
1518         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1519 }
1520 
1521 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1522 {
1523         int ret;
1524         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1525         struct tun_struct *tun = __tun_get(tfile);
1526 
1527         if (!tun)
1528                 return -EBADFD;
1529 
1530         ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1531                            m->msg_flags & MSG_DONTWAIT);
1532         tun_put(tun);
1533         return ret;
1534 }
1535 
1536 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1537                        int flags)
1538 {
1539         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1540         struct tun_struct *tun = __tun_get(tfile);
1541         int ret;
1542 
1543         if (!tun)
1544                 return -EBADFD;
1545 
1546         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1547                 ret = -EINVAL;
1548                 goto out;
1549         }
1550         if (flags & MSG_ERRQUEUE) {
1551                 ret = sock_recv_errqueue(sock->sk, m, total_len,
1552                                          SOL_PACKET, TUN_TX_TIMESTAMP);
1553                 goto out;
1554         }
1555         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1556         if (ret > (ssize_t)total_len) {
1557                 m->msg_flags |= MSG_TRUNC;
1558                 ret = flags & MSG_TRUNC ? ret : total_len;
1559         }
1560 out:
1561         tun_put(tun);
1562         return ret;
1563 }
1564 
1565 /* Ops structure to mimic raw sockets with tun */
1566 static const struct proto_ops tun_socket_ops = {
1567         .sendmsg = tun_sendmsg,
1568         .recvmsg = tun_recvmsg,
1569 };
1570 
1571 static struct proto tun_proto = {
1572         .name           = "tun",
1573         .owner          = THIS_MODULE,
1574         .obj_size       = sizeof(struct tun_file),
1575 };
1576 
1577 static int tun_flags(struct tun_struct *tun)
1578 {
1579         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1580 }
1581 
1582 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1583                               char *buf)
1584 {
1585         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1586         return sprintf(buf, "0x%x\n", tun_flags(tun));
1587 }
1588 
1589 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1590                               char *buf)
1591 {
1592         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1593         return uid_valid(tun->owner)?
1594                 sprintf(buf, "%u\n",
1595                         from_kuid_munged(current_user_ns(), tun->owner)):
1596                 sprintf(buf, "-1\n");
1597 }
1598 
1599 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1600                               char *buf)
1601 {
1602         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1603         return gid_valid(tun->group) ?
1604                 sprintf(buf, "%u\n",
1605                         from_kgid_munged(current_user_ns(), tun->group)):
1606                 sprintf(buf, "-1\n");
1607 }
1608 
1609 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1610 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1611 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1612 
1613 static struct attribute *tun_dev_attrs[] = {
1614         &dev_attr_tun_flags.attr,
1615         &dev_attr_owner.attr,
1616         &dev_attr_group.attr,
1617         NULL
1618 };
1619 
1620 static const struct attribute_group tun_attr_group = {
1621         .attrs = tun_dev_attrs
1622 };
1623 
1624 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1625 {
1626         struct tun_struct *tun;
1627         struct tun_file *tfile = file->private_data;
1628         struct net_device *dev;
1629         int err;
1630 
1631         if (tfile->detached)
1632                 return -EINVAL;
1633 
1634         dev = __dev_get_by_name(net, ifr->ifr_name);
1635         if (dev) {
1636                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1637                         return -EBUSY;
1638                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1639                         tun = netdev_priv(dev);
1640                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1641                         tun = netdev_priv(dev);
1642                 else
1643                         return -EINVAL;
1644 
1645                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1646                     !!(tun->flags & IFF_MULTI_QUEUE))
1647                         return -EINVAL;
1648 
1649                 if (tun_not_capable(tun))
1650                         return -EPERM;
1651                 err = security_tun_dev_open(tun->security);
1652                 if (err < 0)
1653                         return err;
1654 
1655                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1656                 if (err < 0)
1657                         return err;
1658 
1659                 if (tun->flags & IFF_MULTI_QUEUE &&
1660                     (tun->numqueues + tun->numdisabled > 1)) {
1661                         /* One or more queue has already been attached, no need
1662                          * to initialize the device again.
1663                          */
1664                         return 0;
1665                 }
1666         }
1667         else {
1668                 char *name;
1669                 unsigned long flags = 0;
1670                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1671                              MAX_TAP_QUEUES : 1;
1672 
1673                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1674                         return -EPERM;
1675                 err = security_tun_dev_create();
1676                 if (err < 0)
1677                         return err;
1678 
1679                 /* Set dev type */
1680                 if (ifr->ifr_flags & IFF_TUN) {
1681                         /* TUN device */
1682                         flags |= IFF_TUN;
1683                         name = "tun%d";
1684                 } else if (ifr->ifr_flags & IFF_TAP) {
1685                         /* TAP device */
1686                         flags |= IFF_TAP;
1687                         name = "tap%d";
1688                 } else
1689                         return -EINVAL;
1690 
1691                 if (*ifr->ifr_name)
1692                         name = ifr->ifr_name;
1693 
1694                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1695                                        NET_NAME_UNKNOWN, tun_setup, queues,
1696                                        queues);
1697 
1698                 if (!dev)
1699                         return -ENOMEM;
1700 
1701                 dev_net_set(dev, net);
1702                 dev->rtnl_link_ops = &tun_link_ops;
1703                 dev->ifindex = tfile->ifindex;
1704                 dev->sysfs_groups[0] = &tun_attr_group;
1705 
1706                 tun = netdev_priv(dev);
1707                 tun->dev = dev;
1708                 tun->flags = flags;
1709                 tun->txflt.count = 0;
1710                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1711 
1712                 tun->align = NET_SKB_PAD;
1713                 tun->filter_attached = false;
1714                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1715 
1716                 spin_lock_init(&tun->lock);
1717 
1718                 err = security_tun_dev_alloc_security(&tun->security);
1719                 if (err < 0)
1720                         goto err_free_dev;
1721 
1722                 tun_net_init(dev);
1723                 tun_flow_init(tun);
1724 
1725                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1726                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1727                                    NETIF_F_HW_VLAN_STAG_TX;
1728                 dev->features = dev->hw_features;
1729                 dev->vlan_features = dev->features &
1730                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
1731                                        NETIF_F_HW_VLAN_STAG_TX);
1732 
1733                 INIT_LIST_HEAD(&tun->disabled);
1734                 err = tun_attach(tun, file, false);
1735                 if (err < 0)
1736                         goto err_free_flow;
1737 
1738                 err = register_netdevice(tun->dev);
1739                 if (err < 0)
1740                         goto err_detach;
1741         }
1742 
1743         netif_carrier_on(tun->dev);
1744 
1745         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1746 
1747         tun->flags = (tun->flags & ~TUN_FEATURES) |
1748                 (ifr->ifr_flags & TUN_FEATURES);
1749 
1750         /* Make sure persistent devices do not get stuck in
1751          * xoff state.
1752          */
1753         if (netif_running(tun->dev))
1754                 netif_tx_wake_all_queues(tun->dev);
1755 
1756         strcpy(ifr->ifr_name, tun->dev->name);
1757         return 0;
1758 
1759 err_detach:
1760         tun_detach_all(dev);
1761 err_free_flow:
1762         tun_flow_uninit(tun);
1763         security_tun_dev_free_security(tun->security);
1764 err_free_dev:
1765         free_netdev(dev);
1766         return err;
1767 }
1768 
1769 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1770                        struct ifreq *ifr)
1771 {
1772         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1773 
1774         strcpy(ifr->ifr_name, tun->dev->name);
1775 
1776         ifr->ifr_flags = tun_flags(tun);
1777 
1778 }
1779 
1780 /* This is like a cut-down ethtool ops, except done via tun fd so no
1781  * privs required. */
1782 static int set_offload(struct tun_struct *tun, unsigned long arg)
1783 {
1784         netdev_features_t features = 0;
1785 
1786         if (arg & TUN_F_CSUM) {
1787                 features |= NETIF_F_HW_CSUM;
1788                 arg &= ~TUN_F_CSUM;
1789 
1790                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1791                         if (arg & TUN_F_TSO_ECN) {
1792                                 features |= NETIF_F_TSO_ECN;
1793                                 arg &= ~TUN_F_TSO_ECN;
1794                         }
1795                         if (arg & TUN_F_TSO4)
1796                                 features |= NETIF_F_TSO;
1797                         if (arg & TUN_F_TSO6)
1798                                 features |= NETIF_F_TSO6;
1799                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1800                 }
1801 
1802                 if (arg & TUN_F_UFO) {
1803                         features |= NETIF_F_UFO;
1804                         arg &= ~TUN_F_UFO;
1805                 }
1806         }
1807 
1808         /* This gives the user a way to test for new features in future by
1809          * trying to set them. */
1810         if (arg)
1811                 return -EINVAL;
1812 
1813         tun->set_features = features;
1814         netdev_update_features(tun->dev);
1815 
1816         return 0;
1817 }
1818 
1819 static void tun_detach_filter(struct tun_struct *tun, int n)
1820 {
1821         int i;
1822         struct tun_file *tfile;
1823 
1824         for (i = 0; i < n; i++) {
1825                 tfile = rtnl_dereference(tun->tfiles[i]);
1826                 __sk_detach_filter(tfile->socket.sk, lockdep_rtnl_is_held());
1827         }
1828 
1829         tun->filter_attached = false;
1830 }
1831 
1832 static int tun_attach_filter(struct tun_struct *tun)
1833 {
1834         int i, ret = 0;
1835         struct tun_file *tfile;
1836 
1837         for (i = 0; i < tun->numqueues; i++) {
1838                 tfile = rtnl_dereference(tun->tfiles[i]);
1839                 ret = __sk_attach_filter(&tun->fprog, tfile->socket.sk,
1840                                          lockdep_rtnl_is_held());
1841                 if (ret) {
1842                         tun_detach_filter(tun, i);
1843                         return ret;
1844                 }
1845         }
1846 
1847         tun->filter_attached = true;
1848         return ret;
1849 }
1850 
1851 static void tun_set_sndbuf(struct tun_struct *tun)
1852 {
1853         struct tun_file *tfile;
1854         int i;
1855 
1856         for (i = 0; i < tun->numqueues; i++) {
1857                 tfile = rtnl_dereference(tun->tfiles[i]);
1858                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1859         }
1860 }
1861 
1862 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1863 {
1864         struct tun_file *tfile = file->private_data;
1865         struct tun_struct *tun;
1866         int ret = 0;
1867 
1868         rtnl_lock();
1869 
1870         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1871                 tun = tfile->detached;
1872                 if (!tun) {
1873                         ret = -EINVAL;
1874                         goto unlock;
1875                 }
1876                 ret = security_tun_dev_attach_queue(tun->security);
1877                 if (ret < 0)
1878                         goto unlock;
1879                 ret = tun_attach(tun, file, false);
1880         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1881                 tun = rtnl_dereference(tfile->tun);
1882                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1883                         ret = -EINVAL;
1884                 else
1885                         __tun_detach(tfile, false);
1886         } else
1887                 ret = -EINVAL;
1888 
1889 unlock:
1890         rtnl_unlock();
1891         return ret;
1892 }
1893 
1894 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1895                             unsigned long arg, int ifreq_len)
1896 {
1897         struct tun_file *tfile = file->private_data;
1898         struct tun_struct *tun;
1899         void __user* argp = (void __user*)arg;
1900         struct ifreq ifr;
1901         kuid_t owner;
1902         kgid_t group;
1903         int sndbuf;
1904         int vnet_hdr_sz;
1905         unsigned int ifindex;
1906         int le;
1907         int ret;
1908 
1909         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1910                 if (copy_from_user(&ifr, argp, ifreq_len))
1911                         return -EFAULT;
1912         } else {
1913                 memset(&ifr, 0, sizeof(ifr));
1914         }
1915         if (cmd == TUNGETFEATURES) {
1916                 /* Currently this just means: "what IFF flags are valid?".
1917                  * This is needed because we never checked for invalid flags on
1918                  * TUNSETIFF.
1919                  */
1920                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
1921                                 (unsigned int __user*)argp);
1922         } else if (cmd == TUNSETQUEUE)
1923                 return tun_set_queue(file, &ifr);
1924 
1925         ret = 0;
1926         rtnl_lock();
1927 
1928         tun = __tun_get(tfile);
1929         if (cmd == TUNSETIFF && !tun) {
1930                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1931 
1932                 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
1933 
1934                 if (ret)
1935                         goto unlock;
1936 
1937                 if (copy_to_user(argp, &ifr, ifreq_len))
1938                         ret = -EFAULT;
1939                 goto unlock;
1940         }
1941         if (cmd == TUNSETIFINDEX) {
1942                 ret = -EPERM;
1943                 if (tun)
1944                         goto unlock;
1945 
1946                 ret = -EFAULT;
1947                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
1948                         goto unlock;
1949 
1950                 ret = 0;
1951                 tfile->ifindex = ifindex;
1952                 goto unlock;
1953         }
1954 
1955         ret = -EBADFD;
1956         if (!tun)
1957                 goto unlock;
1958 
1959         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1960 
1961         ret = 0;
1962         switch (cmd) {
1963         case TUNGETIFF:
1964                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1965 
1966                 if (tfile->detached)
1967                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
1968                 if (!tfile->socket.sk->sk_filter)
1969                         ifr.ifr_flags |= IFF_NOFILTER;
1970 
1971                 if (copy_to_user(argp, &ifr, ifreq_len))
1972                         ret = -EFAULT;
1973                 break;
1974 
1975         case TUNSETNOCSUM:
1976                 /* Disable/Enable checksum */
1977 
1978                 /* [unimplemented] */
1979                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1980                           arg ? "disabled" : "enabled");
1981                 break;
1982 
1983         case TUNSETPERSIST:
1984                 /* Disable/Enable persist mode. Keep an extra reference to the
1985                  * module to prevent the module being unprobed.
1986                  */
1987                 if (arg && !(tun->flags & IFF_PERSIST)) {
1988                         tun->flags |= IFF_PERSIST;
1989                         __module_get(THIS_MODULE);
1990                 }
1991                 if (!arg && (tun->flags & IFF_PERSIST)) {
1992                         tun->flags &= ~IFF_PERSIST;
1993                         module_put(THIS_MODULE);
1994                 }
1995 
1996                 tun_debug(KERN_INFO, tun, "persist %s\n",
1997                           arg ? "enabled" : "disabled");
1998                 break;
1999 
2000         case TUNSETOWNER:
2001                 /* Set owner of the device */
2002                 owner = make_kuid(current_user_ns(), arg);
2003                 if (!uid_valid(owner)) {
2004                         ret = -EINVAL;
2005                         break;
2006                 }
2007                 tun->owner = owner;
2008                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2009                           from_kuid(&init_user_ns, tun->owner));
2010                 break;
2011 
2012         case TUNSETGROUP:
2013                 /* Set group of the device */
2014                 group = make_kgid(current_user_ns(), arg);
2015                 if (!gid_valid(group)) {
2016                         ret = -EINVAL;
2017                         break;
2018                 }
2019                 tun->group = group;
2020                 tun_debug(KERN_INFO, tun, "group set to %u\n",
2021                           from_kgid(&init_user_ns, tun->group));
2022                 break;
2023 
2024         case TUNSETLINK:
2025                 /* Only allow setting the type when the interface is down */
2026                 if (tun->dev->flags & IFF_UP) {
2027                         tun_debug(KERN_INFO, tun,
2028                                   "Linktype set failed because interface is up\n");
2029                         ret = -EBUSY;
2030                 } else {
2031                         tun->dev->type = (int) arg;
2032                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2033                                   tun->dev->type);
2034                         ret = 0;
2035                 }
2036                 break;
2037 
2038 #ifdef TUN_DEBUG
2039         case TUNSETDEBUG:
2040                 tun->debug = arg;
2041                 break;
2042 #endif
2043         case TUNSETOFFLOAD:
2044                 ret = set_offload(tun, arg);
2045                 break;
2046 
2047         case TUNSETTXFILTER:
2048                 /* Can be set only for TAPs */
2049                 ret = -EINVAL;
2050                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2051                         break;
2052                 ret = update_filter(&tun->txflt, (void __user *)arg);
2053                 break;
2054 
2055         case SIOCGIFHWADDR:
2056                 /* Get hw address */
2057                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2058                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2059                 if (copy_to_user(argp, &ifr, ifreq_len))
2060                         ret = -EFAULT;
2061                 break;
2062 
2063         case SIOCSIFHWADDR:
2064                 /* Set hw address */
2065                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2066                           ifr.ifr_hwaddr.sa_data);
2067 
2068                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2069                 break;
2070 
2071         case TUNGETSNDBUF:
2072                 sndbuf = tfile->socket.sk->sk_sndbuf;
2073                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2074                         ret = -EFAULT;
2075                 break;
2076 
2077         case TUNSETSNDBUF:
2078                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2079                         ret = -EFAULT;
2080                         break;
2081                 }
2082 
2083                 tun->sndbuf = sndbuf;
2084                 tun_set_sndbuf(tun);
2085                 break;
2086 
2087         case TUNGETVNETHDRSZ:
2088                 vnet_hdr_sz = tun->vnet_hdr_sz;
2089                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2090                         ret = -EFAULT;
2091                 break;
2092 
2093         case TUNSETVNETHDRSZ:
2094                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2095                         ret = -EFAULT;
2096                         break;
2097                 }
2098                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2099                         ret = -EINVAL;
2100                         break;
2101                 }
2102 
2103                 tun->vnet_hdr_sz = vnet_hdr_sz;
2104                 break;
2105 
2106         case TUNGETVNETLE:
2107                 le = !!(tun->flags & TUN_VNET_LE);
2108                 if (put_user(le, (int __user *)argp))
2109                         ret = -EFAULT;
2110                 break;
2111 
2112         case TUNSETVNETLE:
2113                 if (get_user(le, (int __user *)argp)) {
2114                         ret = -EFAULT;
2115                         break;
2116                 }
2117                 if (le)
2118                         tun->flags |= TUN_VNET_LE;
2119                 else
2120                         tun->flags &= ~TUN_VNET_LE;
2121                 break;
2122 
2123         case TUNGETVNETBE:
2124                 ret = tun_get_vnet_be(tun, argp);
2125                 break;
2126 
2127         case TUNSETVNETBE:
2128                 ret = tun_set_vnet_be(tun, argp);
2129                 break;
2130 
2131         case TUNATTACHFILTER:
2132                 /* Can be set only for TAPs */
2133                 ret = -EINVAL;
2134                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2135                         break;
2136                 ret = -EFAULT;
2137                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2138                         break;
2139 
2140                 ret = tun_attach_filter(tun);
2141                 break;
2142 
2143         case TUNDETACHFILTER:
2144                 /* Can be set only for TAPs */
2145                 ret = -EINVAL;
2146                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2147                         break;
2148                 ret = 0;
2149                 tun_detach_filter(tun, tun->numqueues);
2150                 break;
2151 
2152         case TUNGETFILTER:
2153                 ret = -EINVAL;
2154                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2155                         break;
2156                 ret = -EFAULT;
2157                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2158                         break;
2159                 ret = 0;
2160                 break;
2161 
2162         default:
2163                 ret = -EINVAL;
2164                 break;
2165         }
2166 
2167 unlock:
2168         rtnl_unlock();
2169         if (tun)
2170                 tun_put(tun);
2171         return ret;
2172 }
2173 
2174 static long tun_chr_ioctl(struct file *file,
2175                           unsigned int cmd, unsigned long arg)
2176 {
2177         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2178 }
2179 
2180 #ifdef CONFIG_COMPAT
2181 static long tun_chr_compat_ioctl(struct file *file,
2182                          unsigned int cmd, unsigned long arg)
2183 {
2184         switch (cmd) {
2185         case TUNSETIFF:
2186         case TUNGETIFF:
2187         case TUNSETTXFILTER:
2188         case TUNGETSNDBUF:
2189         case TUNSETSNDBUF:
2190         case SIOCGIFHWADDR:
2191         case SIOCSIFHWADDR:
2192                 arg = (unsigned long)compat_ptr(arg);
2193                 break;
2194         default:
2195                 arg = (compat_ulong_t)arg;
2196                 break;
2197         }
2198 
2199         /*
2200          * compat_ifreq is shorter than ifreq, so we must not access beyond
2201          * the end of that structure. All fields that are used in this
2202          * driver are compatible though, we don't need to convert the
2203          * contents.
2204          */
2205         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2206 }
2207 #endif /* CONFIG_COMPAT */
2208 
2209 static int tun_chr_fasync(int fd, struct file *file, int on)
2210 {
2211         struct tun_file *tfile = file->private_data;
2212         int ret;
2213 
2214         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2215                 goto out;
2216 
2217         if (on) {
2218                 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2219                 tfile->flags |= TUN_FASYNC;
2220         } else
2221                 tfile->flags &= ~TUN_FASYNC;
2222         ret = 0;
2223 out:
2224         return ret;
2225 }
2226 
2227 static int tun_chr_open(struct inode *inode, struct file * file)
2228 {
2229         struct net *net = current->nsproxy->net_ns;
2230         struct tun_file *tfile;
2231 
2232         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2233 
2234         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2235                                             &tun_proto, 0);
2236         if (!tfile)
2237                 return -ENOMEM;
2238         RCU_INIT_POINTER(tfile->tun, NULL);
2239         tfile->flags = 0;
2240         tfile->ifindex = 0;
2241 
2242         init_waitqueue_head(&tfile->wq.wait);
2243         RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2244 
2245         tfile->socket.file = file;
2246         tfile->socket.ops = &tun_socket_ops;
2247 
2248         sock_init_data(&tfile->socket, &tfile->sk);
2249 
2250         tfile->sk.sk_write_space = tun_sock_write_space;
2251         tfile->sk.sk_sndbuf = INT_MAX;
2252 
2253         file->private_data = tfile;
2254         INIT_LIST_HEAD(&tfile->next);
2255 
2256         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2257 
2258         return 0;
2259 }
2260 
2261 static int tun_chr_close(struct inode *inode, struct file *file)
2262 {
2263         struct tun_file *tfile = file->private_data;
2264 
2265         tun_detach(tfile, true);
2266 
2267         return 0;
2268 }
2269 
2270 #ifdef CONFIG_PROC_FS
2271 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2272 {
2273         struct tun_struct *tun;
2274         struct ifreq ifr;
2275 
2276         memset(&ifr, 0, sizeof(ifr));
2277 
2278         rtnl_lock();
2279         tun = tun_get(f);
2280         if (tun)
2281                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2282         rtnl_unlock();
2283 
2284         if (tun)
2285                 tun_put(tun);
2286 
2287         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2288 }
2289 #endif
2290 
2291 static const struct file_operations tun_fops = {
2292         .owner  = THIS_MODULE,
2293         .llseek = no_llseek,
2294         .read_iter  = tun_chr_read_iter,
2295         .write_iter = tun_chr_write_iter,
2296         .poll   = tun_chr_poll,
2297         .unlocked_ioctl = tun_chr_ioctl,
2298 #ifdef CONFIG_COMPAT
2299         .compat_ioctl = tun_chr_compat_ioctl,
2300 #endif
2301         .open   = tun_chr_open,
2302         .release = tun_chr_close,
2303         .fasync = tun_chr_fasync,
2304 #ifdef CONFIG_PROC_FS
2305         .show_fdinfo = tun_chr_show_fdinfo,
2306 #endif
2307 };
2308 
2309 static struct miscdevice tun_miscdev = {
2310         .minor = TUN_MINOR,
2311         .name = "tun",
2312         .nodename = "net/tun",
2313         .fops = &tun_fops,
2314 };
2315 
2316 /* ethtool interface */
2317 
2318 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2319 {
2320         cmd->supported          = 0;
2321         cmd->advertising        = 0;
2322         ethtool_cmd_speed_set(cmd, SPEED_10);
2323         cmd->duplex             = DUPLEX_FULL;
2324         cmd->port               = PORT_TP;
2325         cmd->phy_address        = 0;
2326         cmd->transceiver        = XCVR_INTERNAL;
2327         cmd->autoneg            = AUTONEG_DISABLE;
2328         cmd->maxtxpkt           = 0;
2329         cmd->maxrxpkt           = 0;
2330         return 0;
2331 }
2332 
2333 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2334 {
2335         struct tun_struct *tun = netdev_priv(dev);
2336 
2337         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2338         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2339 
2340         switch (tun->flags & TUN_TYPE_MASK) {
2341         case IFF_TUN:
2342                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2343                 break;
2344         case IFF_TAP:
2345                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2346                 break;
2347         }
2348 }
2349 
2350 static u32 tun_get_msglevel(struct net_device *dev)
2351 {
2352 #ifdef TUN_DEBUG
2353         struct tun_struct *tun = netdev_priv(dev);
2354         return tun->debug;
2355 #else
2356         return -EOPNOTSUPP;
2357 #endif
2358 }
2359 
2360 static void tun_set_msglevel(struct net_device *dev, u32 value)
2361 {
2362 #ifdef TUN_DEBUG
2363         struct tun_struct *tun = netdev_priv(dev);
2364         tun->debug = value;
2365 #endif
2366 }
2367 
2368 static const struct ethtool_ops tun_ethtool_ops = {
2369         .get_settings   = tun_get_settings,
2370         .get_drvinfo    = tun_get_drvinfo,
2371         .get_msglevel   = tun_get_msglevel,
2372         .set_msglevel   = tun_set_msglevel,
2373         .get_link       = ethtool_op_get_link,
2374         .get_ts_info    = ethtool_op_get_ts_info,
2375 };
2376 
2377 
2378 static int __init tun_init(void)
2379 {
2380         int ret = 0;
2381 
2382         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2383         pr_info("%s\n", DRV_COPYRIGHT);
2384 
2385         ret = rtnl_link_register(&tun_link_ops);
2386         if (ret) {
2387                 pr_err("Can't register link_ops\n");
2388                 goto err_linkops;
2389         }
2390 
2391         ret = misc_register(&tun_miscdev);
2392         if (ret) {
2393                 pr_err("Can't register misc device %d\n", TUN_MINOR);
2394                 goto err_misc;
2395         }
2396         return  0;
2397 err_misc:
2398         rtnl_link_unregister(&tun_link_ops);
2399 err_linkops:
2400         return ret;
2401 }
2402 
2403 static void tun_cleanup(void)
2404 {
2405         misc_deregister(&tun_miscdev);
2406         rtnl_link_unregister(&tun_link_ops);
2407 }
2408 
2409 /* Get an underlying socket object from tun file.  Returns error unless file is
2410  * attached to a device.  The returned object works like a packet socket, it
2411  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2412  * holding a reference to the file for as long as the socket is in use. */
2413 struct socket *tun_get_socket(struct file *file)
2414 {
2415         struct tun_file *tfile;
2416         if (file->f_op != &tun_fops)
2417                 return ERR_PTR(-EINVAL);
2418         tfile = file->private_data;
2419         if (!tfile)
2420                 return ERR_PTR(-EBADFD);
2421         return &tfile->socket;
2422 }
2423 EXPORT_SYMBOL_GPL(tun_get_socket);
2424 
2425 module_init(tun_init);
2426 module_exit(tun_cleanup);
2427 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2428 MODULE_AUTHOR(DRV_COPYRIGHT);
2429 MODULE_LICENSE("GPL");
2430 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2431 MODULE_ALIAS("devname:net/tun");
2432 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us