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Merge tag 'uml-for-linus-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux.git] / drivers / net / tun.c
blob28624cca91f8d124955dcd461573b758e60e36c5
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * TUN - Universal TUN/TAP device driver.
4 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
5 *
6 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
7 */
8
9 /*
10 * Changes:
11 *
12 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
13 * Add TUNSETLINK ioctl to set the link encapsulation
14 *
15 * Mark Smith <markzzzsmith@yahoo.com.au>
16 * Use eth_random_addr() for tap MAC address.
17 *
18 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
19 * Fixes in packet dropping, queue length setting and queue wakeup.
20 * Increased default tx queue length.
21 * Added ethtool API.
22 * Minor cleanups
23 *
24 * Daniel Podlejski <underley@underley.eu.org>
25 * Modifications for 2.3.99-pre5 kernel.
26 */
27
28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29
30 #define DRV_NAME "tun"
31 #define DRV_VERSION "1.6"
32 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
33 #define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
34
35 #include <linux/module.h>
36 #include <linux/errno.h>
37 #include <linux/kernel.h>
38 #include <linux/sched/signal.h>
39 #include <linux/major.h>
40 #include <linux/slab.h>
41 #include <linux/poll.h>
42 #include <linux/fcntl.h>
43 #include <linux/init.h>
44 #include <linux/skbuff.h>
45 #include <linux/netdevice.h>
46 #include <linux/etherdevice.h>
47 #include <linux/miscdevice.h>
48 #include <linux/ethtool.h>
49 #include <linux/rtnetlink.h>
50 #include <linux/compat.h>
51 #include <linux/if.h>
52 #include <linux/if_arp.h>
53 #include <linux/if_ether.h>
54 #include <linux/if_tun.h>
55 #include <linux/if_vlan.h>
56 #include <linux/crc32.h>
57 #include <linux/math.h>
58 #include <linux/nsproxy.h>
59 #include <linux/virtio_net.h>
60 #include <linux/rcupdate.h>
61 #include <net/net_namespace.h>
62 #include <net/netns/generic.h>
63 #include <net/rtnetlink.h>
64 #include <net/sock.h>
65 #include <net/xdp.h>
66 #include <net/ip_tunnels.h>
67 #include <linux/seq_file.h>
68 #include <linux/uio.h>
69 #include <linux/skb_array.h>
70 #include <linux/bpf.h>
71 #include <linux/bpf_trace.h>
72 #include <linux/mutex.h>
73 #include <linux/ieee802154.h>
74 #include <uapi/linux/if_ltalk.h>
75 #include <uapi/linux/if_fddi.h>
76 #include <uapi/linux/if_hippi.h>
77 #include <uapi/linux/if_fc.h>
78 #include <net/ax25.h>
79 #include <net/rose.h>
80 #include <net/6lowpan.h>
81 #include <net/rps.h>
82
83 #include <linux/uaccess.h>
84 #include <linux/proc_fs.h>
85
86 static void tun_default_link_ksettings(struct net_device *dev,
87 struct ethtool_link_ksettings *cmd);
88
89 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
90
91 /* TUN device flags */
92
93 /* IFF_ATTACH_QUEUE is never stored in device flags,
94 * overload it to mean fasync when stored there.
95 */
96 #define TUN_FASYNC IFF_ATTACH_QUEUE
97 /* High bits in flags field are unused. */
98 #define TUN_VNET_LE 0x80000000
99 #define TUN_VNET_BE 0x40000000
100
101 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
102 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
103
104 #define GOODCOPY_LEN 128
105
106 #define FLT_EXACT_COUNT 8
107 struct tap_filter {
108 unsigned int count; /* Number of addrs. Zero means disabled */
109 u32 mask[2]; /* Mask of the hashed addrs */
110 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
111 };
112
113 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
114 * to max number of VCPUs in guest. */
115 #define MAX_TAP_QUEUES 256
116 #define MAX_TAP_FLOWS 4096
117
118 #define TUN_FLOW_EXPIRE (3 * HZ)
119
120 /* A tun_file connects an open character device to a tuntap netdevice. It
121 * also contains all socket related structures (except sock_fprog and tap_filter)
122 * to serve as one transmit queue for tuntap device. The sock_fprog and
123 * tap_filter were kept in tun_struct since they were used for filtering for the
124 * netdevice not for a specific queue (at least I didn't see the requirement for
125 * this).
126 *
127 * RCU usage:
128 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
129 * other can only be read while rcu_read_lock or rtnl_lock is held.
130 */
131 struct tun_file {
132 struct sock sk;
133 struct socket socket;
134 struct tun_struct __rcu *tun;
135 struct fasync_struct *fasync;
136 /* only used for fasnyc */
137 unsigned int flags;
138 union {
139 u16 queue_index;
140 unsigned int ifindex;
141 };
142 struct napi_struct napi;
143 bool napi_enabled;
144 bool napi_frags_enabled;
145 struct mutex napi_mutex; /* Protects access to the above napi */
146 struct list_head next;
147 struct tun_struct *detached;
148 struct ptr_ring tx_ring;
149 struct xdp_rxq_info xdp_rxq;
150 };
151
152 struct tun_page {
153 struct page *page;
154 int count;
155 };
156
157 struct tun_flow_entry {
158 struct hlist_node hash_link;
159 struct rcu_head rcu;
160 struct tun_struct *tun;
161
162 u32 rxhash;
163 u32 rps_rxhash;
164 int queue_index;
165 unsigned long updated ____cacheline_aligned_in_smp;
166 };
167
168 #define TUN_NUM_FLOW_ENTRIES 1024
169 #define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
170
171 struct tun_prog {
172 struct rcu_head rcu;
173 struct bpf_prog *prog;
174 };
175
176 /* Since the socket were moved to tun_file, to preserve the behavior of persist
177 * device, socket filter, sndbuf and vnet header size were restore when the
178 * file were attached to a persist device.
179 */
180 struct tun_struct {
181 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
182 unsigned int numqueues;
183 unsigned int flags;
184 kuid_t owner;
185 kgid_t group;
186
187 struct net_device *dev;
188 netdev_features_t set_features;
189 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
190 NETIF_F_TSO6 | NETIF_F_GSO_UDP_L4)
191
192 int align;
193 int vnet_hdr_sz;
194 int sndbuf;
195 struct tap_filter txflt;
196 struct sock_fprog fprog;
197 /* protected by rtnl lock */
198 bool filter_attached;
199 u32 msg_enable;
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 u32 rx_batched;
209 atomic_long_t rx_frame_errors;
210 struct bpf_prog __rcu *xdp_prog;
211 struct tun_prog __rcu *steering_prog;
212 struct tun_prog __rcu *filter_prog;
213 struct ethtool_link_ksettings link_ksettings;
214 /* init args */
215 struct file *file;
216 struct ifreq *ifr;
217 };
218
219 struct veth {
220 __be16 h_vlan_proto;
221 __be16 h_vlan_TCI;
222 };
223
224 static void tun_flow_init(struct tun_struct *tun);
225 static void tun_flow_uninit(struct tun_struct *tun);
226
227 static int tun_napi_receive(struct napi_struct *napi, int budget)
228 {
229 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
230 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
231 struct sk_buff_head process_queue;
232 struct sk_buff *skb;
233 int received = 0;
234
235 __skb_queue_head_init(&process_queue);
236
237 spin_lock(&queue->lock);
238 skb_queue_splice_tail_init(queue, &process_queue);
239 spin_unlock(&queue->lock);
240
241 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
242 napi_gro_receive(napi, skb);
243 ++received;
244 }
245
246 if (!skb_queue_empty(&process_queue)) {
247 spin_lock(&queue->lock);
248 skb_queue_splice(&process_queue, queue);
249 spin_unlock(&queue->lock);
250 }
251
252 return received;
253 }
254
255 static int tun_napi_poll(struct napi_struct *napi, int budget)
256 {
257 unsigned int received;
258
259 received = tun_napi_receive(napi, budget);
260
261 if (received < budget)
262 napi_complete_done(napi, received);
263
264 return received;
265 }
266
267 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
268 bool napi_en, bool napi_frags)
269 {
270 tfile->napi_enabled = napi_en;
271 tfile->napi_frags_enabled = napi_en && napi_frags;
272 if (napi_en) {
273 netif_napi_add_tx(tun->dev, &tfile->napi, tun_napi_poll);
274 napi_enable(&tfile->napi);
275 }
276 }
277
278 static void tun_napi_enable(struct tun_file *tfile)
279 {
280 if (tfile->napi_enabled)
281 napi_enable(&tfile->napi);
282 }
283
284 static void tun_napi_disable(struct tun_file *tfile)
285 {
286 if (tfile->napi_enabled)
287 napi_disable(&tfile->napi);
288 }
289
290 static void tun_napi_del(struct tun_file *tfile)
291 {
292 if (tfile->napi_enabled)
293 netif_napi_del(&tfile->napi);
294 }
295
296 static bool tun_napi_frags_enabled(const struct tun_file *tfile)
297 {
298 return tfile->napi_frags_enabled;
299 }
300
301 #ifdef CONFIG_TUN_VNET_CROSS_LE
302 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
303 {
304 return tun->flags & TUN_VNET_BE ? false :
305 virtio_legacy_is_little_endian();
306 }
307
308 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
309 {
310 int be = !!(tun->flags & TUN_VNET_BE);
311
312 if (put_user(be, argp))
313 return -EFAULT;
314
315 return 0;
316 }
317
318 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
319 {
320 int be;
321
322 if (get_user(be, argp))
323 return -EFAULT;
324
325 if (be)
326 tun->flags |= TUN_VNET_BE;
327 else
328 tun->flags &= ~TUN_VNET_BE;
329
330 return 0;
331 }
332 #else
333 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
334 {
335 return virtio_legacy_is_little_endian();
336 }
337
338 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
339 {
340 return -EINVAL;
341 }
342
343 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
344 {
345 return -EINVAL;
346 }
347 #endif /* CONFIG_TUN_VNET_CROSS_LE */
348
349 static inline bool tun_is_little_endian(struct tun_struct *tun)
350 {
351 return tun->flags & TUN_VNET_LE ||
352 tun_legacy_is_little_endian(tun);
353 }
354
355 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
356 {
357 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
358 }
359
360 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
361 {
362 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
363 }
364
365 static inline u32 tun_hashfn(u32 rxhash)
366 {
367 return rxhash & TUN_MASK_FLOW_ENTRIES;
368 }
369
370 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
371 {
372 struct tun_flow_entry *e;
373
374 hlist_for_each_entry_rcu(e, head, hash_link) {
375 if (e->rxhash == rxhash)
376 return e;
377 }
378 return NULL;
379 }
380
381 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
382 struct hlist_head *head,
383 u32 rxhash, u16 queue_index)
384 {
385 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
386
387 if (e) {
388 netif_info(tun, tx_queued, tun->dev,
389 "create flow: hash %u index %u\n",
390 rxhash, queue_index);
391 e->updated = jiffies;
392 e->rxhash = rxhash;
393 e->rps_rxhash = 0;
394 e->queue_index = queue_index;
395 e->tun = tun;
396 hlist_add_head_rcu(&e->hash_link, head);
397 ++tun->flow_count;
398 }
399 return e;
400 }
401
402 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
403 {
404 netif_info(tun, tx_queued, tun->dev, "delete flow: hash %u index %u\n",
405 e->rxhash, e->queue_index);
406 hlist_del_rcu(&e->hash_link);
407 kfree_rcu(e, rcu);
408 --tun->flow_count;
409 }
410
411 static void tun_flow_flush(struct tun_struct *tun)
412 {
413 int i;
414
415 spin_lock_bh(&tun->lock);
416 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
417 struct tun_flow_entry *e;
418 struct hlist_node *n;
419
420 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
421 tun_flow_delete(tun, e);
422 }
423 spin_unlock_bh(&tun->lock);
424 }
425
426 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
427 {
428 int i;
429
430 spin_lock_bh(&tun->lock);
431 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
432 struct tun_flow_entry *e;
433 struct hlist_node *n;
434
435 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
436 if (e->queue_index == queue_index)
437 tun_flow_delete(tun, e);
438 }
439 }
440 spin_unlock_bh(&tun->lock);
441 }
442
443 static void tun_flow_cleanup(struct timer_list *t)
444 {
445 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
446 unsigned long delay = tun->ageing_time;
447 unsigned long next_timer = jiffies + delay;
448 unsigned long count = 0;
449 int i;
450
451 spin_lock(&tun->lock);
452 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
453 struct tun_flow_entry *e;
454 struct hlist_node *n;
455
456 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
457 unsigned long this_timer;
458
459 this_timer = e->updated + delay;
460 if (time_before_eq(this_timer, jiffies)) {
461 tun_flow_delete(tun, e);
462 continue;
463 }
464 count++;
465 if (time_before(this_timer, next_timer))
466 next_timer = this_timer;
467 }
468 }
469
470 if (count)
471 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
472 spin_unlock(&tun->lock);
473 }
474
475 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
476 struct tun_file *tfile)
477 {
478 struct hlist_head *head;
479 struct tun_flow_entry *e;
480 unsigned long delay = tun->ageing_time;
481 u16 queue_index = tfile->queue_index;
482
483 head = &tun->flows[tun_hashfn(rxhash)];
484
485 rcu_read_lock();
486
487 e = tun_flow_find(head, rxhash);
488 if (likely(e)) {
489 /* TODO: keep queueing to old queue until it's empty? */
490 if (READ_ONCE(e->queue_index) != queue_index)
491 WRITE_ONCE(e->queue_index, queue_index);
492 if (e->updated != jiffies)
493 e->updated = jiffies;
494 sock_rps_record_flow_hash(e->rps_rxhash);
495 } else {
496 spin_lock_bh(&tun->lock);
497 if (!tun_flow_find(head, rxhash) &&
498 tun->flow_count < MAX_TAP_FLOWS)
499 tun_flow_create(tun, head, rxhash, queue_index);
500
501 if (!timer_pending(&tun->flow_gc_timer))
502 mod_timer(&tun->flow_gc_timer,
503 round_jiffies_up(jiffies + delay));
504 spin_unlock_bh(&tun->lock);
505 }
506
507 rcu_read_unlock();
508 }
509
510 /* Save the hash received in the stack receive path and update the
511 * flow_hash table accordingly.
512 */
513 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
514 {
515 if (unlikely(e->rps_rxhash != hash))
516 e->rps_rxhash = hash;
517 }
518
519 /* We try to identify a flow through its rxhash. The reason that
520 * we do not check rxq no. is because some cards(e.g 82599), chooses
521 * the rxq based on the txq where the last packet of the flow comes. As
522 * the userspace application move between processors, we may get a
523 * different rxq no. here.
524 */
525 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
526 {
527 struct tun_flow_entry *e;
528 u32 txq, numqueues;
529
530 numqueues = READ_ONCE(tun->numqueues);
531
532 txq = __skb_get_hash_symmetric(skb);
533 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
534 if (e) {
535 tun_flow_save_rps_rxhash(e, txq);
536 txq = e->queue_index;
537 } else {
538 txq = reciprocal_scale(txq, numqueues);
539 }
540
541 return txq;
542 }
543
544 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
545 {
546 struct tun_prog *prog;
547 u32 numqueues;
548 u16 ret = 0;
549
550 numqueues = READ_ONCE(tun->numqueues);
551 if (!numqueues)
552 return 0;
553
554 prog = rcu_dereference(tun->steering_prog);
555 if (prog)
556 ret = bpf_prog_run_clear_cb(prog->prog, skb);
557
558 return ret % numqueues;
559 }
560
561 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
562 struct net_device *sb_dev)
563 {
564 struct tun_struct *tun = netdev_priv(dev);
565 u16 ret;
566
567 rcu_read_lock();
568 if (rcu_dereference(tun->steering_prog))
569 ret = tun_ebpf_select_queue(tun, skb);
570 else
571 ret = tun_automq_select_queue(tun, skb);
572 rcu_read_unlock();
573
574 return ret;
575 }
576
577 static inline bool tun_capable(struct tun_struct *tun)
578 {
579 const struct cred *cred = current_cred();
580 struct net *net = dev_net(tun->dev);
581
582 if (ns_capable(net->user_ns, CAP_NET_ADMIN))
583 return 1;
584 if (uid_valid(tun->owner) && uid_eq(cred->euid, tun->owner))
585 return 1;
586 if (gid_valid(tun->group) && in_egroup_p(tun->group))
587 return 1;
588 return 0;
589 }
590
591 static void tun_set_real_num_queues(struct tun_struct *tun)
592 {
593 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
594 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
595 }
596
597 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
598 {
599 tfile->detached = tun;
600 list_add_tail(&tfile->next, &tun->disabled);
601 ++tun->numdisabled;
602 }
603
604 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
605 {
606 struct tun_struct *tun = tfile->detached;
607
608 tfile->detached = NULL;
609 list_del_init(&tfile->next);
610 --tun->numdisabled;
611 return tun;
612 }
613
614 void tun_ptr_free(void *ptr)
615 {
616 if (!ptr)
617 return;
618 if (tun_is_xdp_frame(ptr)) {
619 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
620
621 xdp_return_frame(xdpf);
622 } else {
623 __skb_array_destroy_skb(ptr);
624 }
625 }
626 EXPORT_SYMBOL_GPL(tun_ptr_free);
627
628 static void tun_queue_purge(struct tun_file *tfile)
629 {
630 void *ptr;
631
632 while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
633 tun_ptr_free(ptr);
634
635 skb_queue_purge(&tfile->sk.sk_write_queue);
636 skb_queue_purge(&tfile->sk.sk_error_queue);
637 }
638
639 static void __tun_detach(struct tun_file *tfile, bool clean)
640 {
641 struct tun_file *ntfile;
642 struct tun_struct *tun;
643
644 tun = rtnl_dereference(tfile->tun);
645
646 if (tun && clean) {
647 if (!tfile->detached)
648 tun_napi_disable(tfile);
649 tun_napi_del(tfile);
650 }
651
652 if (tun && !tfile->detached) {
653 u16 index = tfile->queue_index;
654 BUG_ON(index >= tun->numqueues);
655
656 rcu_assign_pointer(tun->tfiles[index],
657 tun->tfiles[tun->numqueues - 1]);
658 ntfile = rtnl_dereference(tun->tfiles[index]);
659 ntfile->queue_index = index;
660 ntfile->xdp_rxq.queue_index = index;
661 rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
662 NULL);
663
664 --tun->numqueues;
665 if (clean) {
666 RCU_INIT_POINTER(tfile->tun, NULL);
667 sock_put(&tfile->sk);
668 } else {
669 tun_disable_queue(tun, tfile);
670 tun_napi_disable(tfile);
671 }
672
673 synchronize_net();
674 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
675 /* Drop read queue */
676 tun_queue_purge(tfile);
677 tun_set_real_num_queues(tun);
678 } else if (tfile->detached && clean) {
679 tun = tun_enable_queue(tfile);
680 sock_put(&tfile->sk);
681 }
682
683 if (clean) {
684 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
685 netif_carrier_off(tun->dev);
686
687 if (!(tun->flags & IFF_PERSIST) &&
688 tun->dev->reg_state == NETREG_REGISTERED)
689 unregister_netdevice(tun->dev);
690 }
691 if (tun)
692 xdp_rxq_info_unreg(&tfile->xdp_rxq);
693 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
694 }
695 }
696
697 static void tun_detach(struct tun_file *tfile, bool clean)
698 {
699 struct tun_struct *tun;
700 struct net_device *dev;
701
702 rtnl_lock();
703 tun = rtnl_dereference(tfile->tun);
704 dev = tun ? tun->dev : NULL;
705 __tun_detach(tfile, clean);
706 if (dev)
707 netdev_state_change(dev);
708 rtnl_unlock();
709
710 if (clean)
711 sock_put(&tfile->sk);
712 }
713
714 static void tun_detach_all(struct net_device *dev)
715 {
716 struct tun_struct *tun = netdev_priv(dev);
717 struct tun_file *tfile, *tmp;
718 int i, n = tun->numqueues;
719
720 for (i = 0; i < n; i++) {
721 tfile = rtnl_dereference(tun->tfiles[i]);
722 BUG_ON(!tfile);
723 tun_napi_disable(tfile);
724 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
725 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
726 RCU_INIT_POINTER(tfile->tun, NULL);
727 --tun->numqueues;
728 }
729 list_for_each_entry(tfile, &tun->disabled, next) {
730 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
731 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
732 RCU_INIT_POINTER(tfile->tun, NULL);
733 }
734 BUG_ON(tun->numqueues != 0);
735
736 synchronize_net();
737 for (i = 0; i < n; i++) {
738 tfile = rtnl_dereference(tun->tfiles[i]);
739 tun_napi_del(tfile);
740 /* Drop read queue */
741 tun_queue_purge(tfile);
742 xdp_rxq_info_unreg(&tfile->xdp_rxq);
743 sock_put(&tfile->sk);
744 }
745 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
746 tun_napi_del(tfile);
747 tun_enable_queue(tfile);
748 tun_queue_purge(tfile);
749 xdp_rxq_info_unreg(&tfile->xdp_rxq);
750 sock_put(&tfile->sk);
751 }
752 BUG_ON(tun->numdisabled != 0);
753
754 if (tun->flags & IFF_PERSIST)
755 module_put(THIS_MODULE);
756 }
757
758 static int tun_attach(struct tun_struct *tun, struct file *file,
759 bool skip_filter, bool napi, bool napi_frags,
760 bool publish_tun)
761 {
762 struct tun_file *tfile = file->private_data;
763 struct net_device *dev = tun->dev;
764 int err;
765
766 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
767 if (err < 0)
768 goto out;
769
770 err = -EINVAL;
771 if (rtnl_dereference(tfile->tun) && !tfile->detached)
772 goto out;
773
774 err = -EBUSY;
775 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
776 goto out;
777
778 err = -E2BIG;
779 if (!tfile->detached &&
780 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
781 goto out;
782
783 err = 0;
784
785 /* Re-attach the filter to persist device */
786 if (!skip_filter && (tun->filter_attached == true)) {
787 lock_sock(tfile->socket.sk);
788 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
789 release_sock(tfile->socket.sk);
790 if (!err)
791 goto out;
792 }
793
794 if (!tfile->detached &&
795 ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
796 GFP_KERNEL, tun_ptr_free)) {
797 err = -ENOMEM;
798 goto out;
799 }
800
801 tfile->queue_index = tun->numqueues;
802 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
803
804 if (tfile->detached) {
805 /* Re-attach detached tfile, updating XDP queue_index */
806 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
807
808 if (tfile->xdp_rxq.queue_index != tfile->queue_index)
809 tfile->xdp_rxq.queue_index = tfile->queue_index;
810 } else {
811 /* Setup XDP RX-queue info, for new tfile getting attached */
812 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
813 tun->dev, tfile->queue_index, 0);
814 if (err < 0)
815 goto out;
816 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
817 MEM_TYPE_PAGE_SHARED, NULL);
818 if (err < 0) {
819 xdp_rxq_info_unreg(&tfile->xdp_rxq);
820 goto out;
821 }
822 err = 0;
823 }
824
825 if (tfile->detached) {
826 tun_enable_queue(tfile);
827 tun_napi_enable(tfile);
828 } else {
829 sock_hold(&tfile->sk);
830 tun_napi_init(tun, tfile, napi, napi_frags);
831 }
832
833 if (rtnl_dereference(tun->xdp_prog))
834 sock_set_flag(&tfile->sk, SOCK_XDP);
835
836 /* device is allowed to go away first, so no need to hold extra
837 * refcnt.
838 */
839
840 /* Publish tfile->tun and tun->tfiles only after we've fully
841 * initialized tfile; otherwise we risk using half-initialized
842 * object.
843 */
844 if (publish_tun)
845 rcu_assign_pointer(tfile->tun, tun);
846 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
847 tun->numqueues++;
848 tun_set_real_num_queues(tun);
849 out:
850 return err;
851 }
852
853 static struct tun_struct *tun_get(struct tun_file *tfile)
854 {
855 struct tun_struct *tun;
856
857 rcu_read_lock();
858 tun = rcu_dereference(tfile->tun);
859 if (tun)
860 dev_hold(tun->dev);
861 rcu_read_unlock();
862
863 return tun;
864 }
865
866 static void tun_put(struct tun_struct *tun)
867 {
868 dev_put(tun->dev);
869 }
870
871 /* TAP filtering */
872 static void addr_hash_set(u32 *mask, const u8 *addr)
873 {
874 int n = ether_crc(ETH_ALEN, addr) >> 26;
875 mask[n >> 5] |= (1 << (n & 31));
876 }
877
878 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
879 {
880 int n = ether_crc(ETH_ALEN, addr) >> 26;
881 return mask[n >> 5] & (1 << (n & 31));
882 }
883
884 static int update_filter(struct tap_filter *filter, void __user *arg)
885 {
886 struct { u8 u[ETH_ALEN]; } *addr;
887 struct tun_filter uf;
888 int err, alen, n, nexact;
889
890 if (copy_from_user(&uf, arg, sizeof(uf)))
891 return -EFAULT;
892
893 if (!uf.count) {
894 /* Disabled */
895 filter->count = 0;
896 return 0;
897 }
898
899 alen = ETH_ALEN * uf.count;
900 addr = memdup_user(arg + sizeof(uf), alen);
901 if (IS_ERR(addr))
902 return PTR_ERR(addr);
903
904 /* The filter is updated without holding any locks. Which is
905 * perfectly safe. We disable it first and in the worst
906 * case we'll accept a few undesired packets. */
907 filter->count = 0;
908 wmb();
909
910 /* Use first set of addresses as an exact filter */
911 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
912 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
913
914 nexact = n;
915
916 /* Remaining multicast addresses are hashed,
917 * unicast will leave the filter disabled. */
918 memset(filter->mask, 0, sizeof(filter->mask));
919 for (; n < uf.count; n++) {
920 if (!is_multicast_ether_addr(addr[n].u)) {
921 err = 0; /* no filter */
922 goto free_addr;
923 }
924 addr_hash_set(filter->mask, addr[n].u);
925 }
926
927 /* For ALLMULTI just set the mask to all ones.
928 * This overrides the mask populated above. */
929 if ((uf.flags & TUN_FLT_ALLMULTI))
930 memset(filter->mask, ~0, sizeof(filter->mask));
931
932 /* Now enable the filter */
933 wmb();
934 filter->count = nexact;
935
936 /* Return the number of exact filters */
937 err = nexact;
938 free_addr:
939 kfree(addr);
940 return err;
941 }
942
943 /* Returns: 0 - drop, !=0 - accept */
944 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
945 {
946 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
947 * at this point. */
948 struct ethhdr *eh = (struct ethhdr *) skb->data;
949 int i;
950
951 /* Exact match */
952 for (i = 0; i < filter->count; i++)
953 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
954 return 1;
955
956 /* Inexact match (multicast only) */
957 if (is_multicast_ether_addr(eh->h_dest))
958 return addr_hash_test(filter->mask, eh->h_dest);
959
960 return 0;
961 }
962
963 /*
964 * Checks whether the packet is accepted or not.
965 * Returns: 0 - drop, !=0 - accept
966 */
967 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
968 {
969 if (!filter->count)
970 return 1;
971
972 return run_filter(filter, skb);
973 }
974
975 /* Network device part of the driver */
976
977 static const struct ethtool_ops tun_ethtool_ops;
978
979 static int tun_net_init(struct net_device *dev)
980 {
981 struct tun_struct *tun = netdev_priv(dev);
982 struct ifreq *ifr = tun->ifr;
983 int err;
984
985 spin_lock_init(&tun->lock);
986
987 err = security_tun_dev_alloc_security(&tun->security);
988 if (err < 0)
989 return err;
990
991 tun_flow_init(tun);
992
993 dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
994 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
995 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
996 NETIF_F_HW_VLAN_STAG_TX;
997 dev->features = dev->hw_features;
998 dev->vlan_features = dev->features &
999 ~(NETIF_F_HW_VLAN_CTAG_TX |
1000 NETIF_F_HW_VLAN_STAG_TX);
1001 dev->lltx = true;
1002
1003 tun->flags = (tun->flags & ~TUN_FEATURES) |
1004 (ifr->ifr_flags & TUN_FEATURES);
1005
1006 INIT_LIST_HEAD(&tun->disabled);
1007 err = tun_attach(tun, tun->file, false, ifr->ifr_flags & IFF_NAPI,
1008 ifr->ifr_flags & IFF_NAPI_FRAGS, false);
1009 if (err < 0) {
1010 tun_flow_uninit(tun);
1011 security_tun_dev_free_security(tun->security);
1012 return err;
1013 }
1014 return 0;
1015 }
1016
1017 /* Net device detach from fd. */
1018 static void tun_net_uninit(struct net_device *dev)
1019 {
1020 tun_detach_all(dev);
1021 }
1022
1023 /* Net device open. */
1024 static int tun_net_open(struct net_device *dev)
1025 {
1026 netif_tx_start_all_queues(dev);
1027
1028 return 0;
1029 }
1030
1031 /* Net device close. */
1032 static int tun_net_close(struct net_device *dev)
1033 {
1034 netif_tx_stop_all_queues(dev);
1035 return 0;
1036 }
1037
1038 /* Net device start xmit */
1039 static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1040 {
1041 #ifdef CONFIG_RPS
1042 if (tun->numqueues == 1 && static_branch_unlikely(&rps_needed)) {
1043 /* Select queue was not called for the skbuff, so we extract the
1044 * RPS hash and save it into the flow_table here.
1045 */
1046 struct tun_flow_entry *e;
1047 __u32 rxhash;
1048
1049 rxhash = __skb_get_hash_symmetric(skb);
1050 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
1051 if (e)
1052 tun_flow_save_rps_rxhash(e, rxhash);
1053 }
1054 #endif
1055 }
1056
1057 static unsigned int run_ebpf_filter(struct tun_struct *tun,
1058 struct sk_buff *skb,
1059 int len)
1060 {
1061 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1062
1063 if (prog)
1064 len = bpf_prog_run_clear_cb(prog->prog, skb);
1065
1066 return len;
1067 }
1068
1069 /* Net device start xmit */
1070 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1071 {
1072 struct tun_struct *tun = netdev_priv(dev);
1073 enum skb_drop_reason drop_reason;
1074 int txq = skb->queue_mapping;
1075 struct netdev_queue *queue;
1076 struct tun_file *tfile;
1077 int len = skb->len;
1078
1079 rcu_read_lock();
1080 tfile = rcu_dereference(tun->tfiles[txq]);
1081
1082 /* Drop packet if interface is not attached */
1083 if (!tfile) {
1084 drop_reason = SKB_DROP_REASON_DEV_READY;
1085 goto drop;
1086 }
1087
1088 if (!rcu_dereference(tun->steering_prog))
1089 tun_automq_xmit(tun, skb);
1090
1091 netif_info(tun, tx_queued, tun->dev, "%s %d\n", __func__, skb->len);
1092
1093 /* Drop if the filter does not like it.
1094 * This is a noop if the filter is disabled.
1095 * Filter can be enabled only for the TAP devices. */
1096 if (!check_filter(&tun->txflt, skb)) {
1097 drop_reason = SKB_DROP_REASON_TAP_TXFILTER;
1098 goto drop;
1099 }
1100
1101 if (tfile->socket.sk->sk_filter &&
1102 sk_filter(tfile->socket.sk, skb)) {
1103 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
1104 goto drop;
1105 }
1106
1107 len = run_ebpf_filter(tun, skb, len);
1108 if (len == 0) {
1109 drop_reason = SKB_DROP_REASON_TAP_FILTER;
1110 goto drop;
1111 }
1112
1113 if (pskb_trim(skb, len)) {
1114 drop_reason = SKB_DROP_REASON_NOMEM;
1115 goto drop;
1116 }
1117
1118 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) {
1119 drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
1120 goto drop;
1121 }
1122
1123 skb_tx_timestamp(skb);
1124
1125 /* Orphan the skb - required as we might hang on to it
1126 * for indefinite time.
1127 */
1128 skb_orphan(skb);
1129
1130 nf_reset_ct(skb);
1131
1132 if (ptr_ring_produce(&tfile->tx_ring, skb)) {
1133 drop_reason = SKB_DROP_REASON_FULL_RING;
1134 goto drop;
1135 }
1136
1137 /* dev->lltx requires to do our own update of trans_start */
1138 queue = netdev_get_tx_queue(dev, txq);
1139 txq_trans_cond_update(queue);
1140
1141 /* Notify and wake up reader process */
1142 if (tfile->flags & TUN_FASYNC)
1143 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1144 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1145
1146 rcu_read_unlock();
1147 return NETDEV_TX_OK;
1148
1149 drop:
1150 dev_core_stats_tx_dropped_inc(dev);
1151 skb_tx_error(skb);
1152 kfree_skb_reason(skb, drop_reason);
1153 rcu_read_unlock();
1154 return NET_XMIT_DROP;
1155 }
1156
1157 static void tun_net_mclist(struct net_device *dev)
1158 {
1159 /*
1160 * This callback is supposed to deal with mc filter in
1161 * _rx_ path and has nothing to do with the _tx_ path.
1162 * In rx path we always accept everything userspace gives us.
1163 */
1164 }
1165
1166 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1167 netdev_features_t features)
1168 {
1169 struct tun_struct *tun = netdev_priv(dev);
1170
1171 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1172 }
1173
1174 static void tun_set_headroom(struct net_device *dev, int new_hr)
1175 {
1176 struct tun_struct *tun = netdev_priv(dev);
1177
1178 if (new_hr < NET_SKB_PAD)
1179 new_hr = NET_SKB_PAD;
1180
1181 tun->align = new_hr;
1182 }
1183
1184 static void
1185 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1186 {
1187 struct tun_struct *tun = netdev_priv(dev);
1188
1189 dev_get_tstats64(dev, stats);
1190
1191 stats->rx_frame_errors +=
1192 (unsigned long)atomic_long_read(&tun->rx_frame_errors);
1193 }
1194
1195 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1196 struct netlink_ext_ack *extack)
1197 {
1198 struct tun_struct *tun = netdev_priv(dev);
1199 struct tun_file *tfile;
1200 struct bpf_prog *old_prog;
1201 int i;
1202
1203 old_prog = rtnl_dereference(tun->xdp_prog);
1204 rcu_assign_pointer(tun->xdp_prog, prog);
1205 if (old_prog)
1206 bpf_prog_put(old_prog);
1207
1208 for (i = 0; i < tun->numqueues; i++) {
1209 tfile = rtnl_dereference(tun->tfiles[i]);
1210 if (prog)
1211 sock_set_flag(&tfile->sk, SOCK_XDP);
1212 else
1213 sock_reset_flag(&tfile->sk, SOCK_XDP);
1214 }
1215 list_for_each_entry(tfile, &tun->disabled, next) {
1216 if (prog)
1217 sock_set_flag(&tfile->sk, SOCK_XDP);
1218 else
1219 sock_reset_flag(&tfile->sk, SOCK_XDP);
1220 }
1221
1222 return 0;
1223 }
1224
1225 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1226 {
1227 switch (xdp->command) {
1228 case XDP_SETUP_PROG:
1229 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1230 default:
1231 return -EINVAL;
1232 }
1233 }
1234
1235 static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1236 {
1237 if (new_carrier) {
1238 struct tun_struct *tun = netdev_priv(dev);
1239
1240 if (!tun->numqueues)
1241 return -EPERM;
1242
1243 netif_carrier_on(dev);
1244 } else {
1245 netif_carrier_off(dev);
1246 }
1247 return 0;
1248 }
1249
1250 static const struct net_device_ops tun_netdev_ops = {
1251 .ndo_init = tun_net_init,
1252 .ndo_uninit = tun_net_uninit,
1253 .ndo_open = tun_net_open,
1254 .ndo_stop = tun_net_close,
1255 .ndo_start_xmit = tun_net_xmit,
1256 .ndo_fix_features = tun_net_fix_features,
1257 .ndo_select_queue = tun_select_queue,
1258 .ndo_set_rx_headroom = tun_set_headroom,
1259 .ndo_get_stats64 = tun_net_get_stats64,
1260 .ndo_change_carrier = tun_net_change_carrier,
1261 };
1262
1263 static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1264 {
1265 /* Notify and wake up reader process */
1266 if (tfile->flags & TUN_FASYNC)
1267 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1268 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1269 }
1270
1271 static int tun_xdp_xmit(struct net_device *dev, int n,
1272 struct xdp_frame **frames, u32 flags)
1273 {
1274 struct tun_struct *tun = netdev_priv(dev);
1275 struct tun_file *tfile;
1276 u32 numqueues;
1277 int nxmit = 0;
1278 int i;
1279
1280 if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1281 return -EINVAL;
1282
1283 rcu_read_lock();
1284
1285 resample:
1286 numqueues = READ_ONCE(tun->numqueues);
1287 if (!numqueues) {
1288 rcu_read_unlock();
1289 return -ENXIO; /* Caller will free/return all frames */
1290 }
1291
1292 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1293 numqueues]);
1294 if (unlikely(!tfile))
1295 goto resample;
1296
1297 spin_lock(&tfile->tx_ring.producer_lock);
1298 for (i = 0; i < n; i++) {
1299 struct xdp_frame *xdp = frames[i];
1300 /* Encode the XDP flag into lowest bit for consumer to differ
1301 * XDP buffer from sk_buff.
1302 */
1303 void *frame = tun_xdp_to_ptr(xdp);
1304
1305 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1306 dev_core_stats_tx_dropped_inc(dev);
1307 break;
1308 }
1309 nxmit++;
1310 }
1311 spin_unlock(&tfile->tx_ring.producer_lock);
1312
1313 if (flags & XDP_XMIT_FLUSH)
1314 __tun_xdp_flush_tfile(tfile);
1315
1316 rcu_read_unlock();
1317 return nxmit;
1318 }
1319
1320 static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1321 {
1322 struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
1323 int nxmit;
1324
1325 if (unlikely(!frame))
1326 return -EOVERFLOW;
1327
1328 nxmit = tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1329 if (!nxmit)
1330 xdp_return_frame_rx_napi(frame);
1331 return nxmit;
1332 }
1333
1334 static const struct net_device_ops tap_netdev_ops = {
1335 .ndo_init = tun_net_init,
1336 .ndo_uninit = tun_net_uninit,
1337 .ndo_open = tun_net_open,
1338 .ndo_stop = tun_net_close,
1339 .ndo_start_xmit = tun_net_xmit,
1340 .ndo_fix_features = tun_net_fix_features,
1341 .ndo_set_rx_mode = tun_net_mclist,
1342 .ndo_set_mac_address = eth_mac_addr,
1343 .ndo_validate_addr = eth_validate_addr,
1344 .ndo_select_queue = tun_select_queue,
1345 .ndo_features_check = passthru_features_check,
1346 .ndo_set_rx_headroom = tun_set_headroom,
1347 .ndo_bpf = tun_xdp,
1348 .ndo_xdp_xmit = tun_xdp_xmit,
1349 .ndo_change_carrier = tun_net_change_carrier,
1350 };
1351
1352 static void tun_flow_init(struct tun_struct *tun)
1353 {
1354 int i;
1355
1356 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1357 INIT_HLIST_HEAD(&tun->flows[i]);
1358
1359 tun->ageing_time = TUN_FLOW_EXPIRE;
1360 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1361 mod_timer(&tun->flow_gc_timer,
1362 round_jiffies_up(jiffies + tun->ageing_time));
1363 }
1364
1365 static void tun_flow_uninit(struct tun_struct *tun)
1366 {
1367 del_timer_sync(&tun->flow_gc_timer);
1368 tun_flow_flush(tun);
1369 }
1370
1371 #define MIN_MTU 68
1372 #define MAX_MTU 65535
1373
1374 /* Initialize net device. */
1375 static void tun_net_initialize(struct net_device *dev)
1376 {
1377 struct tun_struct *tun = netdev_priv(dev);
1378
1379 switch (tun->flags & TUN_TYPE_MASK) {
1380 case IFF_TUN:
1381 dev->netdev_ops = &tun_netdev_ops;
1382 dev->header_ops = &ip_tunnel_header_ops;
1383
1384 /* Point-to-Point TUN Device */
1385 dev->hard_header_len = 0;
1386 dev->addr_len = 0;
1387 dev->mtu = 1500;
1388
1389 /* Zero header length */
1390 dev->type = ARPHRD_NONE;
1391 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1392 break;
1393
1394 case IFF_TAP:
1395 dev->netdev_ops = &tap_netdev_ops;
1396 /* Ethernet TAP Device */
1397 ether_setup(dev);
1398 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1399 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1400
1401 eth_hw_addr_random(dev);
1402
1403 /* Currently tun does not support XDP, only tap does. */
1404 dev->xdp_features = NETDEV_XDP_ACT_BASIC |
1405 NETDEV_XDP_ACT_REDIRECT |
1406 NETDEV_XDP_ACT_NDO_XMIT;
1407
1408 break;
1409 }
1410
1411 dev->min_mtu = MIN_MTU;
1412 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1413 }
1414
1415 static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1416 {
1417 struct sock *sk = tfile->socket.sk;
1418
1419 return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1420 }
1421
1422 /* Character device part */
1423
1424 /* Poll */
1425 static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1426 {
1427 struct tun_file *tfile = file->private_data;
1428 struct tun_struct *tun = tun_get(tfile);
1429 struct sock *sk;
1430 __poll_t mask = 0;
1431
1432 if (!tun)
1433 return EPOLLERR;
1434
1435 sk = tfile->socket.sk;
1436
1437 poll_wait(file, sk_sleep(sk), wait);
1438
1439 if (!ptr_ring_empty(&tfile->tx_ring))
1440 mask |= EPOLLIN | EPOLLRDNORM;
1441
1442 /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1443 * guarantee EPOLLOUT to be raised by either here or
1444 * tun_sock_write_space(). Then process could get notification
1445 * after it writes to a down device and meets -EIO.
1446 */
1447 if (tun_sock_writeable(tun, tfile) ||
1448 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1449 tun_sock_writeable(tun, tfile)))
1450 mask |= EPOLLOUT | EPOLLWRNORM;
1451
1452 if (tun->dev->reg_state != NETREG_REGISTERED)
1453 mask = EPOLLERR;
1454
1455 tun_put(tun);
1456 return mask;
1457 }
1458
1459 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1460 size_t len,
1461 const struct iov_iter *it)
1462 {
1463 struct sk_buff *skb;
1464 size_t linear;
1465 int err;
1466 int i;
1467
1468 if (it->nr_segs > MAX_SKB_FRAGS + 1 ||
1469 len > (ETH_MAX_MTU - NET_SKB_PAD - NET_IP_ALIGN))
1470 return ERR_PTR(-EMSGSIZE);
1471
1472 local_bh_disable();
1473 skb = napi_get_frags(&tfile->napi);
1474 local_bh_enable();
1475 if (!skb)
1476 return ERR_PTR(-ENOMEM);
1477
1478 linear = iov_iter_single_seg_count(it);
1479 err = __skb_grow(skb, linear);
1480 if (err)
1481 goto free;
1482
1483 skb->len = len;
1484 skb->data_len = len - linear;
1485 skb->truesize += skb->data_len;
1486
1487 for (i = 1; i < it->nr_segs; i++) {
1488 const struct iovec *iov = iter_iov(it) + i;
1489 size_t fragsz = iov->iov_len;
1490 struct page *page;
1491 void *frag;
1492
1493 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1494 err = -EINVAL;
1495 goto free;
1496 }
1497 frag = netdev_alloc_frag(fragsz);
1498 if (!frag) {
1499 err = -ENOMEM;
1500 goto free;
1501 }
1502 page = virt_to_head_page(frag);
1503 skb_fill_page_desc(skb, i - 1, page,
1504 frag - page_address(page), fragsz);
1505 }
1506
1507 return skb;
1508 free:
1509 /* frees skb and all frags allocated with napi_alloc_frag() */
1510 napi_free_frags(&tfile->napi);
1511 return ERR_PTR(err);
1512 }
1513
1514 /* prepad is the amount to reserve at front. len is length after that.
1515 * linear is a hint as to how much to copy (usually headers). */
1516 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1517 size_t prepad, size_t len,
1518 size_t linear, int noblock)
1519 {
1520 struct sock *sk = tfile->socket.sk;
1521 struct sk_buff *skb;
1522 int err;
1523
1524 /* Under a page? Don't bother with paged skb. */
1525 if (prepad + len < PAGE_SIZE)
1526 linear = len;
1527
1528 if (len - linear > MAX_SKB_FRAGS * (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
1529 linear = len - MAX_SKB_FRAGS * (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER);
1530 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1531 &err, PAGE_ALLOC_COSTLY_ORDER);
1532 if (!skb)
1533 return ERR_PTR(err);
1534
1535 skb_reserve(skb, prepad);
1536 skb_put(skb, linear);
1537 skb->data_len = len - linear;
1538 skb->len += len - linear;
1539
1540 return skb;
1541 }
1542
1543 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1544 struct sk_buff *skb, int more)
1545 {
1546 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1547 struct sk_buff_head process_queue;
1548 u32 rx_batched = tun->rx_batched;
1549 bool rcv = false;
1550
1551 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1552 local_bh_disable();
1553 skb_record_rx_queue(skb, tfile->queue_index);
1554 netif_receive_skb(skb);
1555 local_bh_enable();
1556 return;
1557 }
1558
1559 spin_lock(&queue->lock);
1560 if (!more || skb_queue_len(queue) == rx_batched) {
1561 __skb_queue_head_init(&process_queue);
1562 skb_queue_splice_tail_init(queue, &process_queue);
1563 rcv = true;
1564 } else {
1565 __skb_queue_tail(queue, skb);
1566 }
1567 spin_unlock(&queue->lock);
1568
1569 if (rcv) {
1570 struct sk_buff *nskb;
1571
1572 local_bh_disable();
1573 while ((nskb = __skb_dequeue(&process_queue))) {
1574 skb_record_rx_queue(nskb, tfile->queue_index);
1575 netif_receive_skb(nskb);
1576 }
1577 skb_record_rx_queue(skb, tfile->queue_index);
1578 netif_receive_skb(skb);
1579 local_bh_enable();
1580 }
1581 }
1582
1583 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1584 int len, int noblock, bool zerocopy)
1585 {
1586 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1587 return false;
1588
1589 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1590 return false;
1591
1592 if (!noblock)
1593 return false;
1594
1595 if (zerocopy)
1596 return false;
1597
1598 if (SKB_DATA_ALIGN(len + TUN_RX_PAD + XDP_PACKET_HEADROOM) +
1599 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1600 return false;
1601
1602 return true;
1603 }
1604
1605 static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
1606 struct page_frag *alloc_frag, char *buf,
1607 int buflen, int len, int pad)
1608 {
1609 struct sk_buff *skb = build_skb(buf, buflen);
1610
1611 if (!skb)
1612 return ERR_PTR(-ENOMEM);
1613
1614 skb_reserve(skb, pad);
1615 skb_put(skb, len);
1616 skb_set_owner_w(skb, tfile->socket.sk);
1617
1618 get_page(alloc_frag->page);
1619 alloc_frag->offset += buflen;
1620
1621 return skb;
1622 }
1623
1624 static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1625 struct xdp_buff *xdp, u32 act)
1626 {
1627 int err;
1628
1629 switch (act) {
1630 case XDP_REDIRECT:
1631 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1632 if (err) {
1633 dev_core_stats_rx_dropped_inc(tun->dev);
1634 return err;
1635 }
1636 dev_sw_netstats_rx_add(tun->dev, xdp->data_end - xdp->data);
1637 break;
1638 case XDP_TX:
1639 err = tun_xdp_tx(tun->dev, xdp);
1640 if (err < 0) {
1641 dev_core_stats_rx_dropped_inc(tun->dev);
1642 return err;
1643 }
1644 dev_sw_netstats_rx_add(tun->dev, xdp->data_end - xdp->data);
1645 break;
1646 case XDP_PASS:
1647 break;
1648 default:
1649 bpf_warn_invalid_xdp_action(tun->dev, xdp_prog, act);
1650 fallthrough;
1651 case XDP_ABORTED:
1652 trace_xdp_exception(tun->dev, xdp_prog, act);
1653 fallthrough;
1654 case XDP_DROP:
1655 dev_core_stats_rx_dropped_inc(tun->dev);
1656 break;
1657 }
1658
1659 return act;
1660 }
1661
1662 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1663 struct tun_file *tfile,
1664 struct iov_iter *from,
1665 struct virtio_net_hdr *hdr,
1666 int len, int *skb_xdp)
1667 {
1668 struct page_frag *alloc_frag = &current->task_frag;
1669 struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
1670 struct bpf_prog *xdp_prog;
1671 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1672 char *buf;
1673 size_t copied;
1674 int pad = TUN_RX_PAD;
1675 int err = 0;
1676
1677 rcu_read_lock();
1678 xdp_prog = rcu_dereference(tun->xdp_prog);
1679 if (xdp_prog)
1680 pad += XDP_PACKET_HEADROOM;
1681 buflen += SKB_DATA_ALIGN(len + pad);
1682 rcu_read_unlock();
1683
1684 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1685 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1686 return ERR_PTR(-ENOMEM);
1687
1688 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1689 copied = copy_page_from_iter(alloc_frag->page,
1690 alloc_frag->offset + pad,
1691 len, from);
1692 if (copied != len)
1693 return ERR_PTR(-EFAULT);
1694
1695 /* There's a small window that XDP may be set after the check
1696 * of xdp_prog above, this should be rare and for simplicity
1697 * we do XDP on skb in case the headroom is not enough.
1698 */
1699 if (hdr->gso_type || !xdp_prog) {
1700 *skb_xdp = 1;
1701 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len,
1702 pad);
1703 }
1704
1705 *skb_xdp = 0;
1706
1707 local_bh_disable();
1708 rcu_read_lock();
1709 bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
1710 xdp_prog = rcu_dereference(tun->xdp_prog);
1711 if (xdp_prog) {
1712 struct xdp_buff xdp;
1713 u32 act;
1714
1715 xdp_init_buff(&xdp, buflen, &tfile->xdp_rxq);
1716 xdp_prepare_buff(&xdp, buf, pad, len, false);
1717
1718 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1719 if (act == XDP_REDIRECT || act == XDP_TX) {
1720 get_page(alloc_frag->page);
1721 alloc_frag->offset += buflen;
1722 }
1723 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1724 if (err < 0) {
1725 if (act == XDP_REDIRECT || act == XDP_TX)
1726 put_page(alloc_frag->page);
1727 goto out;
1728 }
1729
1730 if (err == XDP_REDIRECT)
1731 xdp_do_flush();
1732 if (err != XDP_PASS)
1733 goto out;
1734
1735 pad = xdp.data - xdp.data_hard_start;
1736 len = xdp.data_end - xdp.data;
1737 }
1738 bpf_net_ctx_clear(bpf_net_ctx);
1739 rcu_read_unlock();
1740 local_bh_enable();
1741
1742 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1743
1744 out:
1745 bpf_net_ctx_clear(bpf_net_ctx);
1746 rcu_read_unlock();
1747 local_bh_enable();
1748 return NULL;
1749 }
1750
1751 /* Get packet from user space buffer */
1752 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1753 void *msg_control, struct iov_iter *from,
1754 int noblock, bool more)
1755 {
1756 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1757 struct sk_buff *skb;
1758 size_t total_len = iov_iter_count(from);
1759 size_t len = total_len, align = tun->align, linear;
1760 struct virtio_net_hdr gso = { 0 };
1761 int good_linear;
1762 int copylen;
1763 bool zerocopy = false;
1764 int err;
1765 u32 rxhash = 0;
1766 int skb_xdp = 1;
1767 bool frags = tun_napi_frags_enabled(tfile);
1768 enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
1769
1770 if (!(tun->flags & IFF_NO_PI)) {
1771 if (len < sizeof(pi))
1772 return -EINVAL;
1773 len -= sizeof(pi);
1774
1775 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1776 return -EFAULT;
1777 }
1778
1779 if (tun->flags & IFF_VNET_HDR) {
1780 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1781
1782 if (len < vnet_hdr_sz)
1783 return -EINVAL;
1784 len -= vnet_hdr_sz;
1785
1786 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1787 return -EFAULT;
1788
1789 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1790 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1791 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1792
1793 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1794 return -EINVAL;
1795 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1796 }
1797
1798 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1799 align += NET_IP_ALIGN;
1800 if (unlikely(len < ETH_HLEN ||
1801 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1802 return -EINVAL;
1803 }
1804
1805 good_linear = SKB_MAX_HEAD(align);
1806
1807 if (msg_control) {
1808 struct iov_iter i = *from;
1809
1810 /* There are 256 bytes to be copied in skb, so there is
1811 * enough room for skb expand head in case it is used.
1812 * The rest of the buffer is mapped from userspace.
1813 */
1814 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1815 if (copylen > good_linear)
1816 copylen = good_linear;
1817 linear = copylen;
1818 iov_iter_advance(&i, copylen);
1819 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1820 zerocopy = true;
1821 }
1822
1823 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1824 /* For the packet that is not easy to be processed
1825 * (e.g gso or jumbo packet), we will do it at after
1826 * skb was created with generic XDP routine.
1827 */
1828 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1829 err = PTR_ERR_OR_ZERO(skb);
1830 if (err)
1831 goto drop;
1832 if (!skb)
1833 return total_len;
1834 } else {
1835 if (!zerocopy) {
1836 copylen = len;
1837 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1838 linear = good_linear;
1839 else
1840 linear = tun16_to_cpu(tun, gso.hdr_len);
1841 }
1842
1843 if (frags) {
1844 mutex_lock(&tfile->napi_mutex);
1845 skb = tun_napi_alloc_frags(tfile, copylen, from);
1846 /* tun_napi_alloc_frags() enforces a layout for the skb.
1847 * If zerocopy is enabled, then this layout will be
1848 * overwritten by zerocopy_sg_from_iter().
1849 */
1850 zerocopy = false;
1851 } else {
1852 if (!linear)
1853 linear = min_t(size_t, good_linear, copylen);
1854
1855 skb = tun_alloc_skb(tfile, align, copylen, linear,
1856 noblock);
1857 }
1858
1859 err = PTR_ERR_OR_ZERO(skb);
1860 if (err)
1861 goto drop;
1862
1863 if (zerocopy)
1864 err = zerocopy_sg_from_iter(skb, from);
1865 else
1866 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1867
1868 if (err) {
1869 err = -EFAULT;
1870 drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
1871 goto drop;
1872 }
1873 }
1874
1875 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1876 atomic_long_inc(&tun->rx_frame_errors);
1877 err = -EINVAL;
1878 goto free_skb;
1879 }
1880
1881 switch (tun->flags & TUN_TYPE_MASK) {
1882 case IFF_TUN:
1883 if (tun->flags & IFF_NO_PI) {
1884 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1885
1886 switch (ip_version) {
1887 case 4:
1888 pi.proto = htons(ETH_P_IP);
1889 break;
1890 case 6:
1891 pi.proto = htons(ETH_P_IPV6);
1892 break;
1893 default:
1894 err = -EINVAL;
1895 goto drop;
1896 }
1897 }
1898
1899 skb_reset_mac_header(skb);
1900 skb->protocol = pi.proto;
1901 skb->dev = tun->dev;
1902 break;
1903 case IFF_TAP:
1904 if (frags && !pskb_may_pull(skb, ETH_HLEN)) {
1905 err = -ENOMEM;
1906 drop_reason = SKB_DROP_REASON_HDR_TRUNC;
1907 goto drop;
1908 }
1909 skb->protocol = eth_type_trans(skb, tun->dev);
1910 break;
1911 }
1912
1913 /* copy skb_ubuf_info for callback when skb has no error */
1914 if (zerocopy) {
1915 skb_zcopy_init(skb, msg_control);
1916 } else if (msg_control) {
1917 struct ubuf_info *uarg = msg_control;
1918 uarg->ops->complete(NULL, uarg, false);
1919 }
1920
1921 skb_reset_network_header(skb);
1922 skb_probe_transport_header(skb);
1923 skb_record_rx_queue(skb, tfile->queue_index);
1924
1925 if (skb_xdp) {
1926 struct bpf_prog *xdp_prog;
1927 int ret;
1928
1929 local_bh_disable();
1930 rcu_read_lock();
1931 xdp_prog = rcu_dereference(tun->xdp_prog);
1932 if (xdp_prog) {
1933 ret = do_xdp_generic(xdp_prog, &skb);
1934 if (ret != XDP_PASS) {
1935 rcu_read_unlock();
1936 local_bh_enable();
1937 goto unlock_frags;
1938 }
1939 }
1940 rcu_read_unlock();
1941 local_bh_enable();
1942 }
1943
1944 /* Compute the costly rx hash only if needed for flow updates.
1945 * We may get a very small possibility of OOO during switching, not
1946 * worth to optimize.
1947 */
1948 if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1949 !tfile->detached)
1950 rxhash = __skb_get_hash_symmetric(skb);
1951
1952 rcu_read_lock();
1953 if (unlikely(!(tun->dev->flags & IFF_UP))) {
1954 err = -EIO;
1955 rcu_read_unlock();
1956 drop_reason = SKB_DROP_REASON_DEV_READY;
1957 goto drop;
1958 }
1959
1960 if (frags) {
1961 u32 headlen;
1962
1963 /* Exercise flow dissector code path. */
1964 skb_push(skb, ETH_HLEN);
1965 headlen = eth_get_headlen(tun->dev, skb->data,
1966 skb_headlen(skb));
1967
1968 if (unlikely(headlen > skb_headlen(skb))) {
1969 WARN_ON_ONCE(1);
1970 err = -ENOMEM;
1971 dev_core_stats_rx_dropped_inc(tun->dev);
1972 napi_busy:
1973 napi_free_frags(&tfile->napi);
1974 rcu_read_unlock();
1975 mutex_unlock(&tfile->napi_mutex);
1976 return err;
1977 }
1978
1979 if (likely(napi_schedule_prep(&tfile->napi))) {
1980 local_bh_disable();
1981 napi_gro_frags(&tfile->napi);
1982 napi_complete(&tfile->napi);
1983 local_bh_enable();
1984 } else {
1985 err = -EBUSY;
1986 goto napi_busy;
1987 }
1988 mutex_unlock(&tfile->napi_mutex);
1989 } else if (tfile->napi_enabled) {
1990 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1991 int queue_len;
1992
1993 spin_lock_bh(&queue->lock);
1994
1995 if (unlikely(tfile->detached)) {
1996 spin_unlock_bh(&queue->lock);
1997 rcu_read_unlock();
1998 err = -EBUSY;
1999 goto free_skb;
2000 }
2001
2002 __skb_queue_tail(queue, skb);
2003 queue_len = skb_queue_len(queue);
2004 spin_unlock(&queue->lock);
2005
2006 if (!more || queue_len > NAPI_POLL_WEIGHT)
2007 napi_schedule(&tfile->napi);
2008
2009 local_bh_enable();
2010 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
2011 tun_rx_batched(tun, tfile, skb, more);
2012 } else {
2013 netif_rx(skb);
2014 }
2015 rcu_read_unlock();
2016
2017 preempt_disable();
2018 dev_sw_netstats_rx_add(tun->dev, len);
2019 preempt_enable();
2020
2021 if (rxhash)
2022 tun_flow_update(tun, rxhash, tfile);
2023
2024 return total_len;
2025
2026 drop:
2027 if (err != -EAGAIN)
2028 dev_core_stats_rx_dropped_inc(tun->dev);
2029
2030 free_skb:
2031 if (!IS_ERR_OR_NULL(skb))
2032 kfree_skb_reason(skb, drop_reason);
2033
2034 unlock_frags:
2035 if (frags) {
2036 tfile->napi.skb = NULL;
2037 mutex_unlock(&tfile->napi_mutex);
2038 }
2039
2040 return err ?: total_len;
2041 }
2042
2043 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
2044 {
2045 struct file *file = iocb->ki_filp;
2046 struct tun_file *tfile = file->private_data;
2047 struct tun_struct *tun = tun_get(tfile);
2048 ssize_t result;
2049 int noblock = 0;
2050
2051 if (!tun)
2052 return -EBADFD;
2053
2054 if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
2055 noblock = 1;
2056
2057 result = tun_get_user(tun, tfile, NULL, from, noblock, false);
2058
2059 tun_put(tun);
2060 return result;
2061 }
2062
2063 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2064 struct tun_file *tfile,
2065 struct xdp_frame *xdp_frame,
2066 struct iov_iter *iter)
2067 {
2068 int vnet_hdr_sz = 0;
2069 size_t size = xdp_frame->len;
2070 size_t ret;
2071
2072 if (tun->flags & IFF_VNET_HDR) {
2073 struct virtio_net_hdr gso = { 0 };
2074
2075 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2076 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2077 return -EINVAL;
2078 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2079 sizeof(gso)))
2080 return -EFAULT;
2081 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2082 }
2083
2084 ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2085
2086 preempt_disable();
2087 dev_sw_netstats_tx_add(tun->dev, 1, ret);
2088 preempt_enable();
2089
2090 return ret;
2091 }
2092
2093 /* Put packet to the user space buffer */
2094 static ssize_t tun_put_user(struct tun_struct *tun,
2095 struct tun_file *tfile,
2096 struct sk_buff *skb,
2097 struct iov_iter *iter)
2098 {
2099 struct tun_pi pi = { 0, skb->protocol };
2100 ssize_t total;
2101 int vlan_offset = 0;
2102 int vlan_hlen = 0;
2103 int vnet_hdr_sz = 0;
2104
2105 if (skb_vlan_tag_present(skb))
2106 vlan_hlen = VLAN_HLEN;
2107
2108 if (tun->flags & IFF_VNET_HDR)
2109 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2110
2111 total = skb->len + vlan_hlen + vnet_hdr_sz;
2112
2113 if (!(tun->flags & IFF_NO_PI)) {
2114 if (iov_iter_count(iter) < sizeof(pi))
2115 return -EINVAL;
2116
2117 total += sizeof(pi);
2118 if (iov_iter_count(iter) < total) {
2119 /* Packet will be striped */
2120 pi.flags |= TUN_PKT_STRIP;
2121 }
2122
2123 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2124 return -EFAULT;
2125 }
2126
2127 if (vnet_hdr_sz) {
2128 struct virtio_net_hdr gso;
2129
2130 if (iov_iter_count(iter) < vnet_hdr_sz)
2131 return -EINVAL;
2132
2133 if (virtio_net_hdr_from_skb(skb, &gso,
2134 tun_is_little_endian(tun), true,
2135 vlan_hlen)) {
2136 struct skb_shared_info *sinfo = skb_shinfo(skb);
2137
2138 if (net_ratelimit()) {
2139 netdev_err(tun->dev, "unexpected GSO type: 0x%x, gso_size %d, hdr_len %d\n",
2140 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2141 tun16_to_cpu(tun, gso.hdr_len));
2142 print_hex_dump(KERN_ERR, "tun: ",
2143 DUMP_PREFIX_NONE,
2144 16, 1, skb->head,
2145 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2146 }
2147 WARN_ON_ONCE(1);
2148 return -EINVAL;
2149 }
2150
2151 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2152 return -EFAULT;
2153
2154 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2155 }
2156
2157 if (vlan_hlen) {
2158 int ret;
2159 struct veth veth;
2160
2161 veth.h_vlan_proto = skb->vlan_proto;
2162 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2163
2164 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2165
2166 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2167 if (ret || !iov_iter_count(iter))
2168 goto done;
2169
2170 ret = copy_to_iter(&veth, sizeof(veth), iter);
2171 if (ret != sizeof(veth) || !iov_iter_count(iter))
2172 goto done;
2173 }
2174
2175 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2176
2177 done:
2178 /* caller is in process context, */
2179 preempt_disable();
2180 dev_sw_netstats_tx_add(tun->dev, 1, skb->len + vlan_hlen);
2181 preempt_enable();
2182
2183 return total;
2184 }
2185
2186 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2187 {
2188 DECLARE_WAITQUEUE(wait, current);
2189 void *ptr = NULL;
2190 int error = 0;
2191
2192 ptr = ptr_ring_consume(&tfile->tx_ring);
2193 if (ptr)
2194 goto out;
2195 if (noblock) {
2196 error = -EAGAIN;
2197 goto out;
2198 }
2199
2200 add_wait_queue(&tfile->socket.wq.wait, &wait);
2201
2202 while (1) {
2203 set_current_state(TASK_INTERRUPTIBLE);
2204 ptr = ptr_ring_consume(&tfile->tx_ring);
2205 if (ptr)
2206 break;
2207 if (signal_pending(current)) {
2208 error = -ERESTARTSYS;
2209 break;
2210 }
2211 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2212 error = -EFAULT;
2213 break;
2214 }
2215
2216 schedule();
2217 }
2218
2219 __set_current_state(TASK_RUNNING);
2220 remove_wait_queue(&tfile->socket.wq.wait, &wait);
2221
2222 out:
2223 *err = error;
2224 return ptr;
2225 }
2226
2227 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2228 struct iov_iter *to,
2229 int noblock, void *ptr)
2230 {
2231 ssize_t ret;
2232 int err;
2233
2234 if (!iov_iter_count(to)) {
2235 tun_ptr_free(ptr);
2236 return 0;
2237 }
2238
2239 if (!ptr) {
2240 /* Read frames from ring */
2241 ptr = tun_ring_recv(tfile, noblock, &err);
2242 if (!ptr)
2243 return err;
2244 }
2245
2246 if (tun_is_xdp_frame(ptr)) {
2247 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2248
2249 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2250 xdp_return_frame(xdpf);
2251 } else {
2252 struct sk_buff *skb = ptr;
2253
2254 ret = tun_put_user(tun, tfile, skb, to);
2255 if (unlikely(ret < 0))
2256 kfree_skb(skb);
2257 else
2258 consume_skb(skb);
2259 }
2260
2261 return ret;
2262 }
2263
2264 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2265 {
2266 struct file *file = iocb->ki_filp;
2267 struct tun_file *tfile = file->private_data;
2268 struct tun_struct *tun = tun_get(tfile);
2269 ssize_t len = iov_iter_count(to), ret;
2270 int noblock = 0;
2271
2272 if (!tun)
2273 return -EBADFD;
2274
2275 if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
2276 noblock = 1;
2277
2278 ret = tun_do_read(tun, tfile, to, noblock, NULL);
2279 ret = min_t(ssize_t, ret, len);
2280 if (ret > 0)
2281 iocb->ki_pos = ret;
2282 tun_put(tun);
2283 return ret;
2284 }
2285
2286 static void tun_prog_free(struct rcu_head *rcu)
2287 {
2288 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2289
2290 bpf_prog_destroy(prog->prog);
2291 kfree(prog);
2292 }
2293
2294 static int __tun_set_ebpf(struct tun_struct *tun,
2295 struct tun_prog __rcu **prog_p,
2296 struct bpf_prog *prog)
2297 {
2298 struct tun_prog *old, *new = NULL;
2299
2300 if (prog) {
2301 new = kmalloc(sizeof(*new), GFP_KERNEL);
2302 if (!new)
2303 return -ENOMEM;
2304 new->prog = prog;
2305 }
2306
2307 spin_lock_bh(&tun->lock);
2308 old = rcu_dereference_protected(*prog_p,
2309 lockdep_is_held(&tun->lock));
2310 rcu_assign_pointer(*prog_p, new);
2311 spin_unlock_bh(&tun->lock);
2312
2313 if (old)
2314 call_rcu(&old->rcu, tun_prog_free);
2315
2316 return 0;
2317 }
2318
2319 static void tun_free_netdev(struct net_device *dev)
2320 {
2321 struct tun_struct *tun = netdev_priv(dev);
2322
2323 BUG_ON(!(list_empty(&tun->disabled)));
2324
2325 tun_flow_uninit(tun);
2326 security_tun_dev_free_security(tun->security);
2327 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2328 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2329 }
2330
2331 static void tun_setup(struct net_device *dev)
2332 {
2333 struct tun_struct *tun = netdev_priv(dev);
2334
2335 tun->owner = INVALID_UID;
2336 tun->group = INVALID_GID;
2337 tun_default_link_ksettings(dev, &tun->link_ksettings);
2338
2339 dev->ethtool_ops = &tun_ethtool_ops;
2340 dev->needs_free_netdev = true;
2341 dev->priv_destructor = tun_free_netdev;
2342 /* We prefer our own queue length */
2343 dev->tx_queue_len = TUN_READQ_SIZE;
2344 }
2345
2346 /* Trivial set of netlink ops to allow deleting tun or tap
2347 * device with netlink.
2348 */
2349 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2350 struct netlink_ext_ack *extack)
2351 {
2352 NL_SET_ERR_MSG(extack,
2353 "tun/tap creation via rtnetlink is not supported.");
2354 return -EOPNOTSUPP;
2355 }
2356
2357 static size_t tun_get_size(const struct net_device *dev)
2358 {
2359 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2360 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2361
2362 return nla_total_size(sizeof(uid_t)) + /* OWNER */
2363 nla_total_size(sizeof(gid_t)) + /* GROUP */
2364 nla_total_size(sizeof(u8)) + /* TYPE */
2365 nla_total_size(sizeof(u8)) + /* PI */
2366 nla_total_size(sizeof(u8)) + /* VNET_HDR */
2367 nla_total_size(sizeof(u8)) + /* PERSIST */
2368 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2369 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2370 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2371 0;
2372 }
2373
2374 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2375 {
2376 struct tun_struct *tun = netdev_priv(dev);
2377
2378 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2379 goto nla_put_failure;
2380 if (uid_valid(tun->owner) &&
2381 nla_put_u32(skb, IFLA_TUN_OWNER,
2382 from_kuid_munged(current_user_ns(), tun->owner)))
2383 goto nla_put_failure;
2384 if (gid_valid(tun->group) &&
2385 nla_put_u32(skb, IFLA_TUN_GROUP,
2386 from_kgid_munged(current_user_ns(), tun->group)))
2387 goto nla_put_failure;
2388 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2389 goto nla_put_failure;
2390 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2391 goto nla_put_failure;
2392 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2393 goto nla_put_failure;
2394 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2395 !!(tun->flags & IFF_MULTI_QUEUE)))
2396 goto nla_put_failure;
2397 if (tun->flags & IFF_MULTI_QUEUE) {
2398 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2399 goto nla_put_failure;
2400 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2401 tun->numdisabled))
2402 goto nla_put_failure;
2403 }
2404
2405 return 0;
2406
2407 nla_put_failure:
2408 return -EMSGSIZE;
2409 }
2410
2411 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2412 .kind = DRV_NAME,
2413 .priv_size = sizeof(struct tun_struct),
2414 .setup = tun_setup,
2415 .validate = tun_validate,
2416 .get_size = tun_get_size,
2417 .fill_info = tun_fill_info,
2418 };
2419
2420 static void tun_sock_write_space(struct sock *sk)
2421 {
2422 struct tun_file *tfile;
2423 wait_queue_head_t *wqueue;
2424
2425 if (!sock_writeable(sk))
2426 return;
2427
2428 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2429 return;
2430
2431 wqueue = sk_sleep(sk);
2432 if (wqueue && waitqueue_active(wqueue))
2433 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2434 EPOLLWRNORM | EPOLLWRBAND);
2435
2436 tfile = container_of(sk, struct tun_file, sk);
2437 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2438 }
2439
2440 static void tun_put_page(struct tun_page *tpage)
2441 {
2442 if (tpage->page)
2443 __page_frag_cache_drain(tpage->page, tpage->count);
2444 }
2445
2446 static int tun_xdp_one(struct tun_struct *tun,
2447 struct tun_file *tfile,
2448 struct xdp_buff *xdp, int *flush,
2449 struct tun_page *tpage)
2450 {
2451 unsigned int datasize = xdp->data_end - xdp->data;
2452 struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2453 struct virtio_net_hdr *gso = &hdr->gso;
2454 struct bpf_prog *xdp_prog;
2455 struct sk_buff *skb = NULL;
2456 struct sk_buff_head *queue;
2457 u32 rxhash = 0, act;
2458 int buflen = hdr->buflen;
2459 int ret = 0;
2460 bool skb_xdp = false;
2461 struct page *page;
2462
2463 if (unlikely(datasize < ETH_HLEN))
2464 return -EINVAL;
2465
2466 xdp_prog = rcu_dereference(tun->xdp_prog);
2467 if (xdp_prog) {
2468 if (gso->gso_type) {
2469 skb_xdp = true;
2470 goto build;
2471 }
2472
2473 xdp_init_buff(xdp, buflen, &tfile->xdp_rxq);
2474 xdp_set_data_meta_invalid(xdp);
2475
2476 act = bpf_prog_run_xdp(xdp_prog, xdp);
2477 ret = tun_xdp_act(tun, xdp_prog, xdp, act);
2478 if (ret < 0) {
2479 put_page(virt_to_head_page(xdp->data));
2480 return ret;
2481 }
2482
2483 switch (ret) {
2484 case XDP_REDIRECT:
2485 *flush = true;
2486 fallthrough;
2487 case XDP_TX:
2488 return 0;
2489 case XDP_PASS:
2490 break;
2491 default:
2492 page = virt_to_head_page(xdp->data);
2493 if (tpage->page == page) {
2494 ++tpage->count;
2495 } else {
2496 tun_put_page(tpage);
2497 tpage->page = page;
2498 tpage->count = 1;
2499 }
2500 return 0;
2501 }
2502 }
2503
2504 build:
2505 skb = build_skb(xdp->data_hard_start, buflen);
2506 if (!skb) {
2507 ret = -ENOMEM;
2508 goto out;
2509 }
2510
2511 skb_reserve(skb, xdp->data - xdp->data_hard_start);
2512 skb_put(skb, xdp->data_end - xdp->data);
2513
2514 if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2515 atomic_long_inc(&tun->rx_frame_errors);
2516 kfree_skb(skb);
2517 ret = -EINVAL;
2518 goto out;
2519 }
2520
2521 skb->protocol = eth_type_trans(skb, tun->dev);
2522 skb_reset_network_header(skb);
2523 skb_probe_transport_header(skb);
2524 skb_record_rx_queue(skb, tfile->queue_index);
2525
2526 if (skb_xdp) {
2527 ret = do_xdp_generic(xdp_prog, &skb);
2528 if (ret != XDP_PASS) {
2529 ret = 0;
2530 goto out;
2531 }
2532 }
2533
2534 if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2535 !tfile->detached)
2536 rxhash = __skb_get_hash_symmetric(skb);
2537
2538 if (tfile->napi_enabled) {
2539 queue = &tfile->sk.sk_write_queue;
2540 spin_lock(&queue->lock);
2541
2542 if (unlikely(tfile->detached)) {
2543 spin_unlock(&queue->lock);
2544 kfree_skb(skb);
2545 return -EBUSY;
2546 }
2547
2548 __skb_queue_tail(queue, skb);
2549 spin_unlock(&queue->lock);
2550 ret = 1;
2551 } else {
2552 netif_receive_skb(skb);
2553 ret = 0;
2554 }
2555
2556 /* No need to disable preemption here since this function is
2557 * always called with bh disabled
2558 */
2559 dev_sw_netstats_rx_add(tun->dev, datasize);
2560
2561 if (rxhash)
2562 tun_flow_update(tun, rxhash, tfile);
2563
2564 out:
2565 return ret;
2566 }
2567
2568 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2569 {
2570 int ret, i;
2571 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2572 struct tun_struct *tun = tun_get(tfile);
2573 struct tun_msg_ctl *ctl = m->msg_control;
2574 struct xdp_buff *xdp;
2575
2576 if (!tun)
2577 return -EBADFD;
2578
2579 if (m->msg_controllen == sizeof(struct tun_msg_ctl) &&
2580 ctl && ctl->type == TUN_MSG_PTR) {
2581 struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
2582 struct tun_page tpage;
2583 int n = ctl->num;
2584 int flush = 0, queued = 0;
2585
2586 memset(&tpage, 0, sizeof(tpage));
2587
2588 local_bh_disable();
2589 rcu_read_lock();
2590 bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
2591
2592 for (i = 0; i < n; i++) {
2593 xdp = &((struct xdp_buff *)ctl->ptr)[i];
2594 ret = tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2595 if (ret > 0)
2596 queued += ret;
2597 }
2598
2599 if (flush)
2600 xdp_do_flush();
2601
2602 if (tfile->napi_enabled && queued > 0)
2603 napi_schedule(&tfile->napi);
2604
2605 bpf_net_ctx_clear(bpf_net_ctx);
2606 rcu_read_unlock();
2607 local_bh_enable();
2608
2609 tun_put_page(&tpage);
2610
2611 ret = total_len;
2612 goto out;
2613 }
2614
2615 ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2616 m->msg_flags & MSG_DONTWAIT,
2617 m->msg_flags & MSG_MORE);
2618 out:
2619 tun_put(tun);
2620 return ret;
2621 }
2622
2623 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2624 int flags)
2625 {
2626 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2627 struct tun_struct *tun = tun_get(tfile);
2628 void *ptr = m->msg_control;
2629 int ret;
2630
2631 if (!tun) {
2632 ret = -EBADFD;
2633 goto out_free;
2634 }
2635
2636 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2637 ret = -EINVAL;
2638 goto out_put_tun;
2639 }
2640 if (flags & MSG_ERRQUEUE) {
2641 ret = sock_recv_errqueue(sock->sk, m, total_len,
2642 SOL_PACKET, TUN_TX_TIMESTAMP);
2643 goto out;
2644 }
2645 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2646 if (ret > (ssize_t)total_len) {
2647 m->msg_flags |= MSG_TRUNC;
2648 ret = flags & MSG_TRUNC ? ret : total_len;
2649 }
2650 out:
2651 tun_put(tun);
2652 return ret;
2653
2654 out_put_tun:
2655 tun_put(tun);
2656 out_free:
2657 tun_ptr_free(ptr);
2658 return ret;
2659 }
2660
2661 static int tun_ptr_peek_len(void *ptr)
2662 {
2663 if (likely(ptr)) {
2664 if (tun_is_xdp_frame(ptr)) {
2665 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2666
2667 return xdpf->len;
2668 }
2669 return __skb_array_len_with_tag(ptr);
2670 } else {
2671 return 0;
2672 }
2673 }
2674
2675 static int tun_peek_len(struct socket *sock)
2676 {
2677 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2678 struct tun_struct *tun;
2679 int ret = 0;
2680
2681 tun = tun_get(tfile);
2682 if (!tun)
2683 return 0;
2684
2685 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2686 tun_put(tun);
2687
2688 return ret;
2689 }
2690
2691 /* Ops structure to mimic raw sockets with tun */
2692 static const struct proto_ops tun_socket_ops = {
2693 .peek_len = tun_peek_len,
2694 .sendmsg = tun_sendmsg,
2695 .recvmsg = tun_recvmsg,
2696 };
2697
2698 static struct proto tun_proto = {
2699 .name = "tun",
2700 .owner = THIS_MODULE,
2701 .obj_size = sizeof(struct tun_file),
2702 };
2703
2704 static int tun_flags(struct tun_struct *tun)
2705 {
2706 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2707 }
2708
2709 static ssize_t tun_flags_show(struct device *dev, struct device_attribute *attr,
2710 char *buf)
2711 {
2712 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2713 return sysfs_emit(buf, "0x%x\n", tun_flags(tun));
2714 }
2715
2716 static ssize_t owner_show(struct device *dev, struct device_attribute *attr,
2717 char *buf)
2718 {
2719 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2720 return uid_valid(tun->owner)?
2721 sysfs_emit(buf, "%u\n",
2722 from_kuid_munged(current_user_ns(), tun->owner)) :
2723 sysfs_emit(buf, "-1\n");
2724 }
2725
2726 static ssize_t group_show(struct device *dev, struct device_attribute *attr,
2727 char *buf)
2728 {
2729 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2730 return gid_valid(tun->group) ?
2731 sysfs_emit(buf, "%u\n",
2732 from_kgid_munged(current_user_ns(), tun->group)) :
2733 sysfs_emit(buf, "-1\n");
2734 }
2735
2736 static DEVICE_ATTR_RO(tun_flags);
2737 static DEVICE_ATTR_RO(owner);
2738 static DEVICE_ATTR_RO(group);
2739
2740 static struct attribute *tun_dev_attrs[] = {
2741 &dev_attr_tun_flags.attr,
2742 &dev_attr_owner.attr,
2743 &dev_attr_group.attr,
2744 NULL
2745 };
2746
2747 static const struct attribute_group tun_attr_group = {
2748 .attrs = tun_dev_attrs
2749 };
2750
2751 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2752 {
2753 struct tun_struct *tun;
2754 struct tun_file *tfile = file->private_data;
2755 struct net_device *dev;
2756 int err;
2757
2758 if (tfile->detached)
2759 return -EINVAL;
2760
2761 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2762 if (!capable(CAP_NET_ADMIN))
2763 return -EPERM;
2764
2765 if (!(ifr->ifr_flags & IFF_NAPI) ||
2766 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2767 return -EINVAL;
2768 }
2769
2770 dev = __dev_get_by_name(net, ifr->ifr_name);
2771 if (dev) {
2772 if (ifr->ifr_flags & IFF_TUN_EXCL)
2773 return -EBUSY;
2774 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2775 tun = netdev_priv(dev);
2776 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2777 tun = netdev_priv(dev);
2778 else
2779 return -EINVAL;
2780
2781 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2782 !!(tun->flags & IFF_MULTI_QUEUE))
2783 return -EINVAL;
2784
2785 if (!tun_capable(tun))
2786 return -EPERM;
2787 err = security_tun_dev_open(tun->security);
2788 if (err < 0)
2789 return err;
2790
2791 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2792 ifr->ifr_flags & IFF_NAPI,
2793 ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2794 if (err < 0)
2795 return err;
2796
2797 if (tun->flags & IFF_MULTI_QUEUE &&
2798 (tun->numqueues + tun->numdisabled > 1)) {
2799 /* One or more queue has already been attached, no need
2800 * to initialize the device again.
2801 */
2802 netdev_state_change(dev);
2803 return 0;
2804 }
2805
2806 tun->flags = (tun->flags & ~TUN_FEATURES) |
2807 (ifr->ifr_flags & TUN_FEATURES);
2808
2809 netdev_state_change(dev);
2810 } else {
2811 char *name;
2812 unsigned long flags = 0;
2813 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2814 MAX_TAP_QUEUES : 1;
2815
2816 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2817 return -EPERM;
2818 err = security_tun_dev_create();
2819 if (err < 0)
2820 return err;
2821
2822 /* Set dev type */
2823 if (ifr->ifr_flags & IFF_TUN) {
2824 /* TUN device */
2825 flags |= IFF_TUN;
2826 name = "tun%d";
2827 } else if (ifr->ifr_flags & IFF_TAP) {
2828 /* TAP device */
2829 flags |= IFF_TAP;
2830 name = "tap%d";
2831 } else
2832 return -EINVAL;
2833
2834 if (*ifr->ifr_name)
2835 name = ifr->ifr_name;
2836
2837 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2838 NET_NAME_UNKNOWN, tun_setup, queues,
2839 queues);
2840
2841 if (!dev)
2842 return -ENOMEM;
2843
2844 dev_net_set(dev, net);
2845 dev->rtnl_link_ops = &tun_link_ops;
2846 dev->ifindex = tfile->ifindex;
2847 dev->sysfs_groups[0] = &tun_attr_group;
2848
2849 tun = netdev_priv(dev);
2850 tun->dev = dev;
2851 tun->flags = flags;
2852 tun->txflt.count = 0;
2853 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2854
2855 tun->align = NET_SKB_PAD;
2856 tun->filter_attached = false;
2857 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2858 tun->rx_batched = 0;
2859 RCU_INIT_POINTER(tun->steering_prog, NULL);
2860
2861 tun->ifr = ifr;
2862 tun->file = file;
2863
2864 tun_net_initialize(dev);
2865
2866 err = register_netdevice(tun->dev);
2867 if (err < 0) {
2868 free_netdev(dev);
2869 return err;
2870 }
2871 /* free_netdev() won't check refcnt, to avoid race
2872 * with dev_put() we need publish tun after registration.
2873 */
2874 rcu_assign_pointer(tfile->tun, tun);
2875 }
2876
2877 if (ifr->ifr_flags & IFF_NO_CARRIER)
2878 netif_carrier_off(tun->dev);
2879 else
2880 netif_carrier_on(tun->dev);
2881
2882 /* Make sure persistent devices do not get stuck in
2883 * xoff state.
2884 */
2885 if (netif_running(tun->dev))
2886 netif_tx_wake_all_queues(tun->dev);
2887
2888 strcpy(ifr->ifr_name, tun->dev->name);
2889 return 0;
2890 }
2891
2892 static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2893 {
2894 strcpy(ifr->ifr_name, tun->dev->name);
2895
2896 ifr->ifr_flags = tun_flags(tun);
2897
2898 }
2899
2900 /* This is like a cut-down ethtool ops, except done via tun fd so no
2901 * privs required. */
2902 static int set_offload(struct tun_struct *tun, unsigned long arg)
2903 {
2904 netdev_features_t features = 0;
2905
2906 if (arg & TUN_F_CSUM) {
2907 features |= NETIF_F_HW_CSUM;
2908 arg &= ~TUN_F_CSUM;
2909
2910 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2911 if (arg & TUN_F_TSO_ECN) {
2912 features |= NETIF_F_TSO_ECN;
2913 arg &= ~TUN_F_TSO_ECN;
2914 }
2915 if (arg & TUN_F_TSO4)
2916 features |= NETIF_F_TSO;
2917 if (arg & TUN_F_TSO6)
2918 features |= NETIF_F_TSO6;
2919 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2920 }
2921
2922 arg &= ~TUN_F_UFO;
2923
2924 /* TODO: for now USO4 and USO6 should work simultaneously */
2925 if (arg & TUN_F_USO4 && arg & TUN_F_USO6) {
2926 features |= NETIF_F_GSO_UDP_L4;
2927 arg &= ~(TUN_F_USO4 | TUN_F_USO6);
2928 }
2929 }
2930
2931 /* This gives the user a way to test for new features in future by
2932 * trying to set them. */
2933 if (arg)
2934 return -EINVAL;
2935
2936 tun->set_features = features;
2937 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2938 tun->dev->wanted_features |= features;
2939 netdev_update_features(tun->dev);
2940
2941 return 0;
2942 }
2943
2944 static void tun_detach_filter(struct tun_struct *tun, int n)
2945 {
2946 int i;
2947 struct tun_file *tfile;
2948
2949 for (i = 0; i < n; i++) {
2950 tfile = rtnl_dereference(tun->tfiles[i]);
2951 lock_sock(tfile->socket.sk);
2952 sk_detach_filter(tfile->socket.sk);
2953 release_sock(tfile->socket.sk);
2954 }
2955
2956 tun->filter_attached = false;
2957 }
2958
2959 static int tun_attach_filter(struct tun_struct *tun)
2960 {
2961 int i, ret = 0;
2962 struct tun_file *tfile;
2963
2964 for (i = 0; i < tun->numqueues; i++) {
2965 tfile = rtnl_dereference(tun->tfiles[i]);
2966 lock_sock(tfile->socket.sk);
2967 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2968 release_sock(tfile->socket.sk);
2969 if (ret) {
2970 tun_detach_filter(tun, i);
2971 return ret;
2972 }
2973 }
2974
2975 tun->filter_attached = true;
2976 return ret;
2977 }
2978
2979 static void tun_set_sndbuf(struct tun_struct *tun)
2980 {
2981 struct tun_file *tfile;
2982 int i;
2983
2984 for (i = 0; i < tun->numqueues; i++) {
2985 tfile = rtnl_dereference(tun->tfiles[i]);
2986 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2987 }
2988 }
2989
2990 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2991 {
2992 struct tun_file *tfile = file->private_data;
2993 struct tun_struct *tun;
2994 int ret = 0;
2995
2996 rtnl_lock();
2997
2998 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2999 tun = tfile->detached;
3000 if (!tun) {
3001 ret = -EINVAL;
3002 goto unlock;
3003 }
3004 ret = security_tun_dev_attach_queue(tun->security);
3005 if (ret < 0)
3006 goto unlock;
3007 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
3008 tun->flags & IFF_NAPI_FRAGS, true);
3009 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
3010 tun = rtnl_dereference(tfile->tun);
3011 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
3012 ret = -EINVAL;
3013 else
3014 __tun_detach(tfile, false);
3015 } else
3016 ret = -EINVAL;
3017
3018 if (ret >= 0)
3019 netdev_state_change(tun->dev);
3020
3021 unlock:
3022 rtnl_unlock();
3023 return ret;
3024 }
3025
3026 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog __rcu **prog_p,
3027 void __user *data)
3028 {
3029 struct bpf_prog *prog;
3030 int fd;
3031
3032 if (copy_from_user(&fd, data, sizeof(fd)))
3033 return -EFAULT;
3034
3035 if (fd == -1) {
3036 prog = NULL;
3037 } else {
3038 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
3039 if (IS_ERR(prog))
3040 return PTR_ERR(prog);
3041 }
3042
3043 return __tun_set_ebpf(tun, prog_p, prog);
3044 }
3045
3046 /* Return correct value for tun->dev->addr_len based on tun->dev->type. */
3047 static unsigned char tun_get_addr_len(unsigned short type)
3048 {
3049 switch (type) {
3050 case ARPHRD_IP6GRE:
3051 case ARPHRD_TUNNEL6:
3052 return sizeof(struct in6_addr);
3053 case ARPHRD_IPGRE:
3054 case ARPHRD_TUNNEL:
3055 case ARPHRD_SIT:
3056 return 4;
3057 case ARPHRD_ETHER:
3058 return ETH_ALEN;
3059 case ARPHRD_IEEE802154:
3060 case ARPHRD_IEEE802154_MONITOR:
3061 return IEEE802154_EXTENDED_ADDR_LEN;
3062 case ARPHRD_PHONET_PIPE:
3063 case ARPHRD_PPP:
3064 case ARPHRD_NONE:
3065 return 0;
3066 case ARPHRD_6LOWPAN:
3067 return EUI64_ADDR_LEN;
3068 case ARPHRD_FDDI:
3069 return FDDI_K_ALEN;
3070 case ARPHRD_HIPPI:
3071 return HIPPI_ALEN;
3072 case ARPHRD_IEEE802:
3073 return FC_ALEN;
3074 case ARPHRD_ROSE:
3075 return ROSE_ADDR_LEN;
3076 case ARPHRD_NETROM:
3077 return AX25_ADDR_LEN;
3078 case ARPHRD_LOCALTLK:
3079 return LTALK_ALEN;
3080 default:
3081 return 0;
3082 }
3083 }
3084
3085 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
3086 unsigned long arg, int ifreq_len)
3087 {
3088 struct tun_file *tfile = file->private_data;
3089 struct net *net = sock_net(&tfile->sk);
3090 struct tun_struct *tun;
3091 void __user* argp = (void __user*)arg;
3092 unsigned int carrier;
3093 struct ifreq ifr;
3094 kuid_t owner;
3095 kgid_t group;
3096 int ifindex;
3097 int sndbuf;
3098 int vnet_hdr_sz;
3099 int le;
3100 int ret;
3101 bool do_notify = false;
3102
3103 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3104 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3105 if (copy_from_user(&ifr, argp, ifreq_len))
3106 return -EFAULT;
3107 } else {
3108 memset(&ifr, 0, sizeof(ifr));
3109 }
3110 if (cmd == TUNGETFEATURES) {
3111 /* Currently this just means: "what IFF flags are valid?".
3112 * This is needed because we never checked for invalid flags on
3113 * TUNSETIFF.
3114 */
3115 return put_user(IFF_TUN | IFF_TAP | IFF_NO_CARRIER |
3116 TUN_FEATURES, (unsigned int __user*)argp);
3117 } else if (cmd == TUNSETQUEUE) {
3118 return tun_set_queue(file, &ifr);
3119 } else if (cmd == SIOCGSKNS) {
3120 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3121 return -EPERM;
3122 return open_related_ns(&net->ns, get_net_ns);
3123 }
3124
3125 rtnl_lock();
3126
3127 tun = tun_get(tfile);
3128 if (cmd == TUNSETIFF) {
3129 ret = -EEXIST;
3130 if (tun)
3131 goto unlock;
3132
3133 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3134
3135 ret = tun_set_iff(net, file, &ifr);
3136
3137 if (ret)
3138 goto unlock;
3139
3140 if (copy_to_user(argp, &ifr, ifreq_len))
3141 ret = -EFAULT;
3142 goto unlock;
3143 }
3144 if (cmd == TUNSETIFINDEX) {
3145 ret = -EPERM;
3146 if (tun)
3147 goto unlock;
3148
3149 ret = -EFAULT;
3150 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3151 goto unlock;
3152 ret = -EINVAL;
3153 if (ifindex < 0)
3154 goto unlock;
3155 ret = 0;
3156 tfile->ifindex = ifindex;
3157 goto unlock;
3158 }
3159
3160 ret = -EBADFD;
3161 if (!tun)
3162 goto unlock;
3163
3164 netif_info(tun, drv, tun->dev, "tun_chr_ioctl cmd %u\n", cmd);
3165
3166 net = dev_net(tun->dev);
3167 ret = 0;
3168 switch (cmd) {
3169 case TUNGETIFF:
3170 tun_get_iff(tun, &ifr);
3171
3172 if (tfile->detached)
3173 ifr.ifr_flags |= IFF_DETACH_QUEUE;
3174 if (!tfile->socket.sk->sk_filter)
3175 ifr.ifr_flags |= IFF_NOFILTER;
3176
3177 if (copy_to_user(argp, &ifr, ifreq_len))
3178 ret = -EFAULT;
3179 break;
3180
3181 case TUNSETNOCSUM:
3182 /* Disable/Enable checksum */
3183
3184 /* [unimplemented] */
3185 netif_info(tun, drv, tun->dev, "ignored: set checksum %s\n",
3186 arg ? "disabled" : "enabled");
3187 break;
3188
3189 case TUNSETPERSIST:
3190 /* Disable/Enable persist mode. Keep an extra reference to the
3191 * module to prevent the module being unprobed.
3192 */
3193 if (arg && !(tun->flags & IFF_PERSIST)) {
3194 tun->flags |= IFF_PERSIST;
3195 __module_get(THIS_MODULE);
3196 do_notify = true;
3197 }
3198 if (!arg && (tun->flags & IFF_PERSIST)) {
3199 tun->flags &= ~IFF_PERSIST;
3200 module_put(THIS_MODULE);
3201 do_notify = true;
3202 }
3203
3204 netif_info(tun, drv, tun->dev, "persist %s\n",
3205 arg ? "enabled" : "disabled");
3206 break;
3207
3208 case TUNSETOWNER:
3209 /* Set owner of the device */
3210 owner = make_kuid(current_user_ns(), arg);
3211 if (!uid_valid(owner)) {
3212 ret = -EINVAL;
3213 break;
3214 }
3215 tun->owner = owner;
3216 do_notify = true;
3217 netif_info(tun, drv, tun->dev, "owner set to %u\n",
3218 from_kuid(&init_user_ns, tun->owner));
3219 break;
3220
3221 case TUNSETGROUP:
3222 /* Set group of the device */
3223 group = make_kgid(current_user_ns(), arg);
3224 if (!gid_valid(group)) {
3225 ret = -EINVAL;
3226 break;
3227 }
3228 tun->group = group;
3229 do_notify = true;
3230 netif_info(tun, drv, tun->dev, "group set to %u\n",
3231 from_kgid(&init_user_ns, tun->group));
3232 break;
3233
3234 case TUNSETLINK:
3235 /* Only allow setting the type when the interface is down */
3236 if (tun->dev->flags & IFF_UP) {
3237 netif_info(tun, drv, tun->dev,
3238 "Linktype set failed because interface is up\n");
3239 ret = -EBUSY;
3240 } else {
3241 ret = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE,
3242 tun->dev);
3243 ret = notifier_to_errno(ret);
3244 if (ret) {
3245 netif_info(tun, drv, tun->dev,
3246 "Refused to change device type\n");
3247 break;
3248 }
3249 tun->dev->type = (int) arg;
3250 tun->dev->addr_len = tun_get_addr_len(tun->dev->type);
3251 netif_info(tun, drv, tun->dev, "linktype set to %d\n",
3252 tun->dev->type);
3253 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE,
3254 tun->dev);
3255 }
3256 break;
3257
3258 case TUNSETDEBUG:
3259 tun->msg_enable = (u32)arg;
3260 break;
3261
3262 case TUNSETOFFLOAD:
3263 ret = set_offload(tun, arg);
3264 break;
3265
3266 case TUNSETTXFILTER:
3267 /* Can be set only for TAPs */
3268 ret = -EINVAL;
3269 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3270 break;
3271 ret = update_filter(&tun->txflt, (void __user *)arg);
3272 break;
3273
3274 case SIOCGIFHWADDR:
3275 /* Get hw address */
3276 dev_get_mac_address(&ifr.ifr_hwaddr, net, tun->dev->name);
3277 if (copy_to_user(argp, &ifr, ifreq_len))
3278 ret = -EFAULT;
3279 break;
3280
3281 case SIOCSIFHWADDR:
3282 /* Set hw address */
3283 ret = dev_set_mac_address_user(tun->dev, &ifr.ifr_hwaddr, NULL);
3284 break;
3285
3286 case TUNGETSNDBUF:
3287 sndbuf = tfile->socket.sk->sk_sndbuf;
3288 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3289 ret = -EFAULT;
3290 break;
3291
3292 case TUNSETSNDBUF:
3293 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3294 ret = -EFAULT;
3295 break;
3296 }
3297 if (sndbuf <= 0) {
3298 ret = -EINVAL;
3299 break;
3300 }
3301
3302 tun->sndbuf = sndbuf;
3303 tun_set_sndbuf(tun);
3304 break;
3305
3306 case TUNGETVNETHDRSZ:
3307 vnet_hdr_sz = tun->vnet_hdr_sz;
3308 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3309 ret = -EFAULT;
3310 break;
3311
3312 case TUNSETVNETHDRSZ:
3313 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3314 ret = -EFAULT;
3315 break;
3316 }
3317 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3318 ret = -EINVAL;
3319 break;
3320 }
3321
3322 tun->vnet_hdr_sz = vnet_hdr_sz;
3323 break;
3324
3325 case TUNGETVNETLE:
3326 le = !!(tun->flags & TUN_VNET_LE);
3327 if (put_user(le, (int __user *)argp))
3328 ret = -EFAULT;
3329 break;
3330
3331 case TUNSETVNETLE:
3332 if (get_user(le, (int __user *)argp)) {
3333 ret = -EFAULT;
3334 break;
3335 }
3336 if (le)
3337 tun->flags |= TUN_VNET_LE;
3338 else
3339 tun->flags &= ~TUN_VNET_LE;
3340 break;
3341
3342 case TUNGETVNETBE:
3343 ret = tun_get_vnet_be(tun, argp);
3344 break;
3345
3346 case TUNSETVNETBE:
3347 ret = tun_set_vnet_be(tun, argp);
3348 break;
3349
3350 case TUNATTACHFILTER:
3351 /* Can be set only for TAPs */
3352 ret = -EINVAL;
3353 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3354 break;
3355 ret = -EFAULT;
3356 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3357 break;
3358
3359 ret = tun_attach_filter(tun);
3360 break;
3361
3362 case TUNDETACHFILTER:
3363 /* Can be set only for TAPs */
3364 ret = -EINVAL;
3365 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3366 break;
3367 ret = 0;
3368 tun_detach_filter(tun, tun->numqueues);
3369 break;
3370
3371 case TUNGETFILTER:
3372 ret = -EINVAL;
3373 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3374 break;
3375 ret = -EFAULT;
3376 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3377 break;
3378 ret = 0;
3379 break;
3380
3381 case TUNSETSTEERINGEBPF:
3382 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3383 break;
3384
3385 case TUNSETFILTEREBPF:
3386 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3387 break;
3388
3389 case TUNSETCARRIER:
3390 ret = -EFAULT;
3391 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3392 goto unlock;
3393
3394 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3395 break;
3396
3397 case TUNGETDEVNETNS:
3398 ret = -EPERM;
3399 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3400 goto unlock;
3401 ret = open_related_ns(&net->ns, get_net_ns);
3402 break;
3403
3404 default:
3405 ret = -EINVAL;
3406 break;
3407 }
3408
3409 if (do_notify)
3410 netdev_state_change(tun->dev);
3411
3412 unlock:
3413 rtnl_unlock();
3414 if (tun)
3415 tun_put(tun);
3416 return ret;
3417 }
3418
3419 static long tun_chr_ioctl(struct file *file,
3420 unsigned int cmd, unsigned long arg)
3421 {
3422 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3423 }
3424
3425 #ifdef CONFIG_COMPAT
3426 static long tun_chr_compat_ioctl(struct file *file,
3427 unsigned int cmd, unsigned long arg)
3428 {
3429 switch (cmd) {
3430 case TUNSETIFF:
3431 case TUNGETIFF:
3432 case TUNSETTXFILTER:
3433 case TUNGETSNDBUF:
3434 case TUNSETSNDBUF:
3435 case SIOCGIFHWADDR:
3436 case SIOCSIFHWADDR:
3437 arg = (unsigned long)compat_ptr(arg);
3438 break;
3439 default:
3440 arg = (compat_ulong_t)arg;
3441 break;
3442 }
3443
3444 /*
3445 * compat_ifreq is shorter than ifreq, so we must not access beyond
3446 * the end of that structure. All fields that are used in this
3447 * driver are compatible though, we don't need to convert the
3448 * contents.
3449 */
3450 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3451 }
3452 #endif /* CONFIG_COMPAT */
3453
3454 static int tun_chr_fasync(int fd, struct file *file, int on)
3455 {
3456 struct tun_file *tfile = file->private_data;
3457 int ret;
3458
3459 if (on) {
3460 ret = file_f_owner_allocate(file);
3461 if (ret)
3462 goto out;
3463 }
3464
3465 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3466 goto out;
3467
3468 if (on) {
3469 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3470 tfile->flags |= TUN_FASYNC;
3471 } else
3472 tfile->flags &= ~TUN_FASYNC;
3473 ret = 0;
3474 out:
3475 return ret;
3476 }
3477
3478 static int tun_chr_open(struct inode *inode, struct file * file)
3479 {
3480 struct net *net = current->nsproxy->net_ns;
3481 struct tun_file *tfile;
3482
3483 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3484 &tun_proto, 0);
3485 if (!tfile)
3486 return -ENOMEM;
3487 if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3488 sk_free(&tfile->sk);
3489 return -ENOMEM;
3490 }
3491
3492 mutex_init(&tfile->napi_mutex);
3493 RCU_INIT_POINTER(tfile->tun, NULL);
3494 tfile->flags = 0;
3495 tfile->ifindex = 0;
3496
3497 init_waitqueue_head(&tfile->socket.wq.wait);
3498
3499 tfile->socket.file = file;
3500 tfile->socket.ops = &tun_socket_ops;
3501
3502 sock_init_data_uid(&tfile->socket, &tfile->sk, current_fsuid());
3503
3504 tfile->sk.sk_write_space = tun_sock_write_space;
3505 tfile->sk.sk_sndbuf = INT_MAX;
3506
3507 file->private_data = tfile;
3508 INIT_LIST_HEAD(&tfile->next);
3509
3510 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3511
3512 /* tun groks IOCB_NOWAIT just fine, mark it as such */
3513 file->f_mode |= FMODE_NOWAIT;
3514 return 0;
3515 }
3516
3517 static int tun_chr_close(struct inode *inode, struct file *file)
3518 {
3519 struct tun_file *tfile = file->private_data;
3520
3521 tun_detach(tfile, true);
3522
3523 return 0;
3524 }
3525
3526 #ifdef CONFIG_PROC_FS
3527 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3528 {
3529 struct tun_file *tfile = file->private_data;
3530 struct tun_struct *tun;
3531 struct ifreq ifr;
3532
3533 memset(&ifr, 0, sizeof(ifr));
3534
3535 rtnl_lock();
3536 tun = tun_get(tfile);
3537 if (tun)
3538 tun_get_iff(tun, &ifr);
3539 rtnl_unlock();
3540
3541 if (tun)
3542 tun_put(tun);
3543
3544 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3545 }
3546 #endif
3547
3548 static const struct file_operations tun_fops = {
3549 .owner = THIS_MODULE,
3550 .read_iter = tun_chr_read_iter,
3551 .write_iter = tun_chr_write_iter,
3552 .poll = tun_chr_poll,
3553 .unlocked_ioctl = tun_chr_ioctl,
3554 #ifdef CONFIG_COMPAT
3555 .compat_ioctl = tun_chr_compat_ioctl,
3556 #endif
3557 .open = tun_chr_open,
3558 .release = tun_chr_close,
3559 .fasync = tun_chr_fasync,
3560 #ifdef CONFIG_PROC_FS
3561 .show_fdinfo = tun_chr_show_fdinfo,
3562 #endif
3563 };
3564
3565 static struct miscdevice tun_miscdev = {
3566 .minor = TUN_MINOR,
3567 .name = "tun",
3568 .nodename = "net/tun",
3569 .fops = &tun_fops,
3570 };
3571
3572 /* ethtool interface */
3573
3574 static void tun_default_link_ksettings(struct net_device *dev,
3575 struct ethtool_link_ksettings *cmd)
3576 {
3577 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3578 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3579 cmd->base.speed = SPEED_10000;
3580 cmd->base.duplex = DUPLEX_FULL;
3581 cmd->base.port = PORT_TP;
3582 cmd->base.phy_address = 0;
3583 cmd->base.autoneg = AUTONEG_DISABLE;
3584 }
3585
3586 static int tun_get_link_ksettings(struct net_device *dev,
3587 struct ethtool_link_ksettings *cmd)
3588 {
3589 struct tun_struct *tun = netdev_priv(dev);
3590
3591 memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3592 return 0;
3593 }
3594
3595 static int tun_set_link_ksettings(struct net_device *dev,
3596 const struct ethtool_link_ksettings *cmd)
3597 {
3598 struct tun_struct *tun = netdev_priv(dev);
3599
3600 memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3601 return 0;
3602 }
3603
3604 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3605 {
3606 struct tun_struct *tun = netdev_priv(dev);
3607
3608 strscpy(info->driver, DRV_NAME, sizeof(info->driver));
3609 strscpy(info->version, DRV_VERSION, sizeof(info->version));
3610
3611 switch (tun->flags & TUN_TYPE_MASK) {
3612 case IFF_TUN:
3613 strscpy(info->bus_info, "tun", sizeof(info->bus_info));
3614 break;
3615 case IFF_TAP:
3616 strscpy(info->bus_info, "tap", sizeof(info->bus_info));
3617 break;
3618 }
3619 }
3620
3621 static u32 tun_get_msglevel(struct net_device *dev)
3622 {
3623 struct tun_struct *tun = netdev_priv(dev);
3624
3625 return tun->msg_enable;
3626 }
3627
3628 static void tun_set_msglevel(struct net_device *dev, u32 value)
3629 {
3630 struct tun_struct *tun = netdev_priv(dev);
3631
3632 tun->msg_enable = value;
3633 }
3634
3635 static int tun_get_coalesce(struct net_device *dev,
3636 struct ethtool_coalesce *ec,
3637 struct kernel_ethtool_coalesce *kernel_coal,
3638 struct netlink_ext_ack *extack)
3639 {
3640 struct tun_struct *tun = netdev_priv(dev);
3641
3642 ec->rx_max_coalesced_frames = tun->rx_batched;
3643
3644 return 0;
3645 }
3646
3647 static int tun_set_coalesce(struct net_device *dev,
3648 struct ethtool_coalesce *ec,
3649 struct kernel_ethtool_coalesce *kernel_coal,
3650 struct netlink_ext_ack *extack)
3651 {
3652 struct tun_struct *tun = netdev_priv(dev);
3653
3654 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3655 tun->rx_batched = NAPI_POLL_WEIGHT;
3656 else
3657 tun->rx_batched = ec->rx_max_coalesced_frames;
3658
3659 return 0;
3660 }
3661
3662 static void tun_get_channels(struct net_device *dev,
3663 struct ethtool_channels *channels)
3664 {
3665 struct tun_struct *tun = netdev_priv(dev);
3666
3667 channels->combined_count = tun->numqueues;
3668 channels->max_combined = tun->flags & IFF_MULTI_QUEUE ? MAX_TAP_QUEUES : 1;
3669 }
3670
3671 static const struct ethtool_ops tun_ethtool_ops = {
3672 .supported_coalesce_params = ETHTOOL_COALESCE_RX_MAX_FRAMES,
3673 .get_drvinfo = tun_get_drvinfo,
3674 .get_msglevel = tun_get_msglevel,
3675 .set_msglevel = tun_set_msglevel,
3676 .get_link = ethtool_op_get_link,
3677 .get_channels = tun_get_channels,
3678 .get_ts_info = ethtool_op_get_ts_info,
3679 .get_coalesce = tun_get_coalesce,
3680 .set_coalesce = tun_set_coalesce,
3681 .get_link_ksettings = tun_get_link_ksettings,
3682 .set_link_ksettings = tun_set_link_ksettings,
3683 };
3684
3685 static int tun_queue_resize(struct tun_struct *tun)
3686 {
3687 struct net_device *dev = tun->dev;
3688 struct tun_file *tfile;
3689 struct ptr_ring **rings;
3690 int n = tun->numqueues + tun->numdisabled;
3691 int ret, i;
3692
3693 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3694 if (!rings)
3695 return -ENOMEM;
3696
3697 for (i = 0; i < tun->numqueues; i++) {
3698 tfile = rtnl_dereference(tun->tfiles[i]);
3699 rings[i] = &tfile->tx_ring;
3700 }
3701 list_for_each_entry(tfile, &tun->disabled, next)
3702 rings[i++] = &tfile->tx_ring;
3703
3704 ret = ptr_ring_resize_multiple_bh(rings, n,
3705 dev->tx_queue_len, GFP_KERNEL,
3706 tun_ptr_free);
3707
3708 kfree(rings);
3709 return ret;
3710 }
3711
3712 static int tun_device_event(struct notifier_block *unused,
3713 unsigned long event, void *ptr)
3714 {
3715 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3716 struct tun_struct *tun = netdev_priv(dev);
3717 int i;
3718
3719 if (dev->rtnl_link_ops != &tun_link_ops)
3720 return NOTIFY_DONE;
3721
3722 switch (event) {
3723 case NETDEV_CHANGE_TX_QUEUE_LEN:
3724 if (tun_queue_resize(tun))
3725 return NOTIFY_BAD;
3726 break;
3727 case NETDEV_UP:
3728 for (i = 0; i < tun->numqueues; i++) {
3729 struct tun_file *tfile;
3730
3731 tfile = rtnl_dereference(tun->tfiles[i]);
3732 tfile->socket.sk->sk_write_space(tfile->socket.sk);
3733 }
3734 break;
3735 default:
3736 break;
3737 }
3738
3739 return NOTIFY_DONE;
3740 }
3741
3742 static struct notifier_block tun_notifier_block __read_mostly = {
3743 .notifier_call = tun_device_event,
3744 };
3745
3746 static int __init tun_init(void)
3747 {
3748 int ret = 0;
3749
3750 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3751
3752 ret = rtnl_link_register(&tun_link_ops);
3753 if (ret) {
3754 pr_err("Can't register link_ops\n");
3755 goto err_linkops;
3756 }
3757
3758 ret = misc_register(&tun_miscdev);
3759 if (ret) {
3760 pr_err("Can't register misc device %d\n", TUN_MINOR);
3761 goto err_misc;
3762 }
3763
3764 ret = register_netdevice_notifier(&tun_notifier_block);
3765 if (ret) {
3766 pr_err("Can't register netdevice notifier\n");
3767 goto err_notifier;
3768 }
3769
3770 return 0;
3771
3772 err_notifier:
3773 misc_deregister(&tun_miscdev);
3774 err_misc:
3775 rtnl_link_unregister(&tun_link_ops);
3776 err_linkops:
3777 return ret;
3778 }
3779
3780 static void __exit tun_cleanup(void)
3781 {
3782 misc_deregister(&tun_miscdev);
3783 rtnl_link_unregister(&tun_link_ops);
3784 unregister_netdevice_notifier(&tun_notifier_block);
3785 }
3786
3787 /* Get an underlying socket object from tun file. Returns error unless file is
3788 * attached to a device. The returned object works like a packet socket, it
3789 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3790 * holding a reference to the file for as long as the socket is in use. */
3791 struct socket *tun_get_socket(struct file *file)
3792 {
3793 struct tun_file *tfile;
3794 if (file->f_op != &tun_fops)
3795 return ERR_PTR(-EINVAL);
3796 tfile = file->private_data;
3797 if (!tfile)
3798 return ERR_PTR(-EBADFD);
3799 return &tfile->socket;
3800 }
3801 EXPORT_SYMBOL_GPL(tun_get_socket);
3802
3803 struct ptr_ring *tun_get_tx_ring(struct file *file)
3804 {
3805 struct tun_file *tfile;
3806
3807 if (file->f_op != &tun_fops)
3808 return ERR_PTR(-EINVAL);
3809 tfile = file->private_data;
3810 if (!tfile)
3811 return ERR_PTR(-EBADFD);
3812 return &tfile->tx_ring;
3813 }
3814 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3815
3816 module_init(tun_init);
3817 module_exit(tun_cleanup);
3818 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3819 MODULE_AUTHOR(DRV_COPYRIGHT);
3820 MODULE_LICENSE("GPL");
3821 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3822 MODULE_ALIAS("devname:net/tun");
Linux Kernel