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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / drivers / net / tun.c
blob650c937ed56bbb62640188801c38a1aa1f937c3b
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/nsproxy.h>
58 #include <linux/virtio_net.h>
59 #include <linux/rcupdate.h>
60 #include <net/net_namespace.h>
61 #include <net/netns/generic.h>
62 #include <net/rtnetlink.h>
63 #include <net/sock.h>
64 #include <net/xdp.h>
65 #include <linux/seq_file.h>
66 #include <linux/uio.h>
67 #include <linux/skb_array.h>
68 #include <linux/bpf.h>
69 #include <linux/bpf_trace.h>
70 #include <linux/mutex.h>
71
72 #include <linux/uaccess.h>
73 #include <linux/proc_fs.h>
74
75 static void tun_default_link_ksettings(struct net_device *dev,
76 struct ethtool_link_ksettings *cmd);
77
78 /* Uncomment to enable debugging */
79 /* #define TUN_DEBUG 1 */
80
81 #ifdef TUN_DEBUG
82 static int debug;
83
84 #define tun_debug(level, tun, fmt, args...) \
85 do { \
86 if (tun->debug) \
87 netdev_printk(level, tun->dev, fmt, ##args); \
88 } while (0)
89 #define DBG1(level, fmt, args...) \
90 do { \
91 if (debug == 2) \
92 printk(level fmt, ##args); \
93 } while (0)
94 #else
95 #define tun_debug(level, tun, fmt, args...) \
96 do { \
97 if (0) \
98 netdev_printk(level, tun->dev, fmt, ##args); \
99 } while (0)
100 #define DBG1(level, fmt, args...) \
101 do { \
102 if (0) \
103 printk(level fmt, ##args); \
104 } while (0)
105 #endif
106
107 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
108
109 /* TUN device flags */
110
111 /* IFF_ATTACH_QUEUE is never stored in device flags,
112 * overload it to mean fasync when stored there.
113 */
114 #define TUN_FASYNC IFF_ATTACH_QUEUE
115 /* High bits in flags field are unused. */
116 #define TUN_VNET_LE 0x80000000
117 #define TUN_VNET_BE 0x40000000
118
119 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
120 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
121
122 #define GOODCOPY_LEN 128
123
124 #define FLT_EXACT_COUNT 8
125 struct tap_filter {
126 unsigned int count; /* Number of addrs. Zero means disabled */
127 u32 mask[2]; /* Mask of the hashed addrs */
128 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
129 };
130
131 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
132 * to max number of VCPUs in guest. */
133 #define MAX_TAP_QUEUES 256
134 #define MAX_TAP_FLOWS 4096
135
136 #define TUN_FLOW_EXPIRE (3 * HZ)
137
138 struct tun_pcpu_stats {
139 u64_stats_t rx_packets;
140 u64_stats_t rx_bytes;
141 u64_stats_t tx_packets;
142 u64_stats_t tx_bytes;
143 struct u64_stats_sync syncp;
144 u32 rx_dropped;
145 u32 tx_dropped;
146 u32 rx_frame_errors;
147 };
148
149 /* A tun_file connects an open character device to a tuntap netdevice. It
150 * also contains all socket related structures (except sock_fprog and tap_filter)
151 * to serve as one transmit queue for tuntap device. The sock_fprog and
152 * tap_filter were kept in tun_struct since they were used for filtering for the
153 * netdevice not for a specific queue (at least I didn't see the requirement for
154 * this).
155 *
156 * RCU usage:
157 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
158 * other can only be read while rcu_read_lock or rtnl_lock is held.
159 */
160 struct tun_file {
161 struct sock sk;
162 struct socket socket;
163 struct tun_struct __rcu *tun;
164 struct fasync_struct *fasync;
165 /* only used for fasnyc */
166 unsigned int flags;
167 union {
168 u16 queue_index;
169 unsigned int ifindex;
170 };
171 struct napi_struct napi;
172 bool napi_enabled;
173 bool napi_frags_enabled;
174 struct mutex napi_mutex; /* Protects access to the above napi */
175 struct list_head next;
176 struct tun_struct *detached;
177 struct ptr_ring tx_ring;
178 struct xdp_rxq_info xdp_rxq;
179 };
180
181 struct tun_page {
182 struct page *page;
183 int count;
184 };
185
186 struct tun_flow_entry {
187 struct hlist_node hash_link;
188 struct rcu_head rcu;
189 struct tun_struct *tun;
190
191 u32 rxhash;
192 u32 rps_rxhash;
193 int queue_index;
194 unsigned long updated ____cacheline_aligned_in_smp;
195 };
196
197 #define TUN_NUM_FLOW_ENTRIES 1024
198 #define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
199
200 struct tun_prog {
201 struct rcu_head rcu;
202 struct bpf_prog *prog;
203 };
204
205 /* Since the socket were moved to tun_file, to preserve the behavior of persist
206 * device, socket filter, sndbuf and vnet header size were restore when the
207 * file were attached to a persist device.
208 */
209 struct tun_struct {
210 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
211 unsigned int numqueues;
212 unsigned int flags;
213 kuid_t owner;
214 kgid_t group;
215
216 struct net_device *dev;
217 netdev_features_t set_features;
218 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
219 NETIF_F_TSO6)
220
221 int align;
222 int vnet_hdr_sz;
223 int sndbuf;
224 struct tap_filter txflt;
225 struct sock_fprog fprog;
226 /* protected by rtnl lock */
227 bool filter_attached;
228 #ifdef TUN_DEBUG
229 int debug;
230 #endif
231 spinlock_t lock;
232 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
233 struct timer_list flow_gc_timer;
234 unsigned long ageing_time;
235 unsigned int numdisabled;
236 struct list_head disabled;
237 void *security;
238 u32 flow_count;
239 u32 rx_batched;
240 struct tun_pcpu_stats __percpu *pcpu_stats;
241 struct bpf_prog __rcu *xdp_prog;
242 struct tun_prog __rcu *steering_prog;
243 struct tun_prog __rcu *filter_prog;
244 struct ethtool_link_ksettings link_ksettings;
245 };
246
247 struct veth {
248 __be16 h_vlan_proto;
249 __be16 h_vlan_TCI;
250 };
251
252 bool tun_is_xdp_frame(void *ptr)
253 {
254 return (unsigned long)ptr & TUN_XDP_FLAG;
255 }
256 EXPORT_SYMBOL(tun_is_xdp_frame);
257
258 void *tun_xdp_to_ptr(void *ptr)
259 {
260 return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
261 }
262 EXPORT_SYMBOL(tun_xdp_to_ptr);
263
264 void *tun_ptr_to_xdp(void *ptr)
265 {
266 return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
267 }
268 EXPORT_SYMBOL(tun_ptr_to_xdp);
269
270 static int tun_napi_receive(struct napi_struct *napi, int budget)
271 {
272 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
273 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
274 struct sk_buff_head process_queue;
275 struct sk_buff *skb;
276 int received = 0;
277
278 __skb_queue_head_init(&process_queue);
279
280 spin_lock(&queue->lock);
281 skb_queue_splice_tail_init(queue, &process_queue);
282 spin_unlock(&queue->lock);
283
284 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
285 napi_gro_receive(napi, skb);
286 ++received;
287 }
288
289 if (!skb_queue_empty(&process_queue)) {
290 spin_lock(&queue->lock);
291 skb_queue_splice(&process_queue, queue);
292 spin_unlock(&queue->lock);
293 }
294
295 return received;
296 }
297
298 static int tun_napi_poll(struct napi_struct *napi, int budget)
299 {
300 unsigned int received;
301
302 received = tun_napi_receive(napi, budget);
303
304 if (received < budget)
305 napi_complete_done(napi, received);
306
307 return received;
308 }
309
310 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
311 bool napi_en, bool napi_frags)
312 {
313 tfile->napi_enabled = napi_en;
314 tfile->napi_frags_enabled = napi_en && napi_frags;
315 if (napi_en) {
316 netif_tx_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
317 NAPI_POLL_WEIGHT);
318 napi_enable(&tfile->napi);
319 }
320 }
321
322 static void tun_napi_disable(struct tun_file *tfile)
323 {
324 if (tfile->napi_enabled)
325 napi_disable(&tfile->napi);
326 }
327
328 static void tun_napi_del(struct tun_file *tfile)
329 {
330 if (tfile->napi_enabled)
331 netif_napi_del(&tfile->napi);
332 }
333
334 static bool tun_napi_frags_enabled(const struct tun_file *tfile)
335 {
336 return tfile->napi_frags_enabled;
337 }
338
339 #ifdef CONFIG_TUN_VNET_CROSS_LE
340 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
341 {
342 return tun->flags & TUN_VNET_BE ? false :
343 virtio_legacy_is_little_endian();
344 }
345
346 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
347 {
348 int be = !!(tun->flags & TUN_VNET_BE);
349
350 if (put_user(be, argp))
351 return -EFAULT;
352
353 return 0;
354 }
355
356 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
357 {
358 int be;
359
360 if (get_user(be, argp))
361 return -EFAULT;
362
363 if (be)
364 tun->flags |= TUN_VNET_BE;
365 else
366 tun->flags &= ~TUN_VNET_BE;
367
368 return 0;
369 }
370 #else
371 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
372 {
373 return virtio_legacy_is_little_endian();
374 }
375
376 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
377 {
378 return -EINVAL;
379 }
380
381 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
382 {
383 return -EINVAL;
384 }
385 #endif /* CONFIG_TUN_VNET_CROSS_LE */
386
387 static inline bool tun_is_little_endian(struct tun_struct *tun)
388 {
389 return tun->flags & TUN_VNET_LE ||
390 tun_legacy_is_little_endian(tun);
391 }
392
393 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
394 {
395 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
396 }
397
398 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
399 {
400 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
401 }
402
403 static inline u32 tun_hashfn(u32 rxhash)
404 {
405 return rxhash & TUN_MASK_FLOW_ENTRIES;
406 }
407
408 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
409 {
410 struct tun_flow_entry *e;
411
412 hlist_for_each_entry_rcu(e, head, hash_link) {
413 if (e->rxhash == rxhash)
414 return e;
415 }
416 return NULL;
417 }
418
419 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
420 struct hlist_head *head,
421 u32 rxhash, u16 queue_index)
422 {
423 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
424
425 if (e) {
426 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
427 rxhash, queue_index);
428 e->updated = jiffies;
429 e->rxhash = rxhash;
430 e->rps_rxhash = 0;
431 e->queue_index = queue_index;
432 e->tun = tun;
433 hlist_add_head_rcu(&e->hash_link, head);
434 ++tun->flow_count;
435 }
436 return e;
437 }
438
439 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
440 {
441 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
442 e->rxhash, e->queue_index);
443 hlist_del_rcu(&e->hash_link);
444 kfree_rcu(e, rcu);
445 --tun->flow_count;
446 }
447
448 static void tun_flow_flush(struct tun_struct *tun)
449 {
450 int i;
451
452 spin_lock_bh(&tun->lock);
453 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
454 struct tun_flow_entry *e;
455 struct hlist_node *n;
456
457 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
458 tun_flow_delete(tun, e);
459 }
460 spin_unlock_bh(&tun->lock);
461 }
462
463 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
464 {
465 int i;
466
467 spin_lock_bh(&tun->lock);
468 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
469 struct tun_flow_entry *e;
470 struct hlist_node *n;
471
472 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
473 if (e->queue_index == queue_index)
474 tun_flow_delete(tun, e);
475 }
476 }
477 spin_unlock_bh(&tun->lock);
478 }
479
480 static void tun_flow_cleanup(struct timer_list *t)
481 {
482 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
483 unsigned long delay = tun->ageing_time;
484 unsigned long next_timer = jiffies + delay;
485 unsigned long count = 0;
486 int i;
487
488 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
489
490 spin_lock(&tun->lock);
491 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
492 struct tun_flow_entry *e;
493 struct hlist_node *n;
494
495 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
496 unsigned long this_timer;
497
498 this_timer = e->updated + delay;
499 if (time_before_eq(this_timer, jiffies)) {
500 tun_flow_delete(tun, e);
501 continue;
502 }
503 count++;
504 if (time_before(this_timer, next_timer))
505 next_timer = this_timer;
506 }
507 }
508
509 if (count)
510 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
511 spin_unlock(&tun->lock);
512 }
513
514 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
515 struct tun_file *tfile)
516 {
517 struct hlist_head *head;
518 struct tun_flow_entry *e;
519 unsigned long delay = tun->ageing_time;
520 u16 queue_index = tfile->queue_index;
521
522 head = &tun->flows[tun_hashfn(rxhash)];
523
524 rcu_read_lock();
525
526 e = tun_flow_find(head, rxhash);
527 if (likely(e)) {
528 /* TODO: keep queueing to old queue until it's empty? */
529 if (READ_ONCE(e->queue_index) != queue_index)
530 WRITE_ONCE(e->queue_index, queue_index);
531 if (e->updated != jiffies)
532 e->updated = jiffies;
533 sock_rps_record_flow_hash(e->rps_rxhash);
534 } else {
535 spin_lock_bh(&tun->lock);
536 if (!tun_flow_find(head, rxhash) &&
537 tun->flow_count < MAX_TAP_FLOWS)
538 tun_flow_create(tun, head, rxhash, queue_index);
539
540 if (!timer_pending(&tun->flow_gc_timer))
541 mod_timer(&tun->flow_gc_timer,
542 round_jiffies_up(jiffies + delay));
543 spin_unlock_bh(&tun->lock);
544 }
545
546 rcu_read_unlock();
547 }
548
549 /**
550 * Save the hash received in the stack receive path and update the
551 * flow_hash table accordingly.
552 */
553 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
554 {
555 if (unlikely(e->rps_rxhash != hash))
556 e->rps_rxhash = hash;
557 }
558
559 /* We try to identify a flow through its rxhash. The reason that
560 * we do not check rxq no. is because some cards(e.g 82599), chooses
561 * the rxq based on the txq where the last packet of the flow comes. As
562 * the userspace application move between processors, we may get a
563 * different rxq no. here.
564 */
565 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
566 {
567 struct tun_flow_entry *e;
568 u32 txq = 0;
569 u32 numqueues = 0;
570
571 numqueues = READ_ONCE(tun->numqueues);
572
573 txq = __skb_get_hash_symmetric(skb);
574 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
575 if (e) {
576 tun_flow_save_rps_rxhash(e, txq);
577 txq = e->queue_index;
578 } else {
579 /* use multiply and shift instead of expensive divide */
580 txq = ((u64)txq * numqueues) >> 32;
581 }
582
583 return txq;
584 }
585
586 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
587 {
588 struct tun_prog *prog;
589 u32 numqueues;
590 u16 ret = 0;
591
592 numqueues = READ_ONCE(tun->numqueues);
593 if (!numqueues)
594 return 0;
595
596 prog = rcu_dereference(tun->steering_prog);
597 if (prog)
598 ret = bpf_prog_run_clear_cb(prog->prog, skb);
599
600 return ret % numqueues;
601 }
602
603 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
604 struct net_device *sb_dev)
605 {
606 struct tun_struct *tun = netdev_priv(dev);
607 u16 ret;
608
609 rcu_read_lock();
610 if (rcu_dereference(tun->steering_prog))
611 ret = tun_ebpf_select_queue(tun, skb);
612 else
613 ret = tun_automq_select_queue(tun, skb);
614 rcu_read_unlock();
615
616 return ret;
617 }
618
619 static inline bool tun_not_capable(struct tun_struct *tun)
620 {
621 const struct cred *cred = current_cred();
622 struct net *net = dev_net(tun->dev);
623
624 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
625 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
626 !ns_capable(net->user_ns, CAP_NET_ADMIN);
627 }
628
629 static void tun_set_real_num_queues(struct tun_struct *tun)
630 {
631 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
632 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
633 }
634
635 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
636 {
637 tfile->detached = tun;
638 list_add_tail(&tfile->next, &tun->disabled);
639 ++tun->numdisabled;
640 }
641
642 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
643 {
644 struct tun_struct *tun = tfile->detached;
645
646 tfile->detached = NULL;
647 list_del_init(&tfile->next);
648 --tun->numdisabled;
649 return tun;
650 }
651
652 void tun_ptr_free(void *ptr)
653 {
654 if (!ptr)
655 return;
656 if (tun_is_xdp_frame(ptr)) {
657 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
658
659 xdp_return_frame(xdpf);
660 } else {
661 __skb_array_destroy_skb(ptr);
662 }
663 }
664 EXPORT_SYMBOL_GPL(tun_ptr_free);
665
666 static void tun_queue_purge(struct tun_file *tfile)
667 {
668 void *ptr;
669
670 while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
671 tun_ptr_free(ptr);
672
673 skb_queue_purge(&tfile->sk.sk_write_queue);
674 skb_queue_purge(&tfile->sk.sk_error_queue);
675 }
676
677 static void __tun_detach(struct tun_file *tfile, bool clean)
678 {
679 struct tun_file *ntfile;
680 struct tun_struct *tun;
681
682 tun = rtnl_dereference(tfile->tun);
683
684 if (tun && clean) {
685 tun_napi_disable(tfile);
686 tun_napi_del(tfile);
687 }
688
689 if (tun && !tfile->detached) {
690 u16 index = tfile->queue_index;
691 BUG_ON(index >= tun->numqueues);
692
693 rcu_assign_pointer(tun->tfiles[index],
694 tun->tfiles[tun->numqueues - 1]);
695 ntfile = rtnl_dereference(tun->tfiles[index]);
696 ntfile->queue_index = index;
697 rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
698 NULL);
699
700 --tun->numqueues;
701 if (clean) {
702 RCU_INIT_POINTER(tfile->tun, NULL);
703 sock_put(&tfile->sk);
704 } else
705 tun_disable_queue(tun, tfile);
706
707 synchronize_net();
708 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
709 /* Drop read queue */
710 tun_queue_purge(tfile);
711 tun_set_real_num_queues(tun);
712 } else if (tfile->detached && clean) {
713 tun = tun_enable_queue(tfile);
714 sock_put(&tfile->sk);
715 }
716
717 if (clean) {
718 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
719 netif_carrier_off(tun->dev);
720
721 if (!(tun->flags & IFF_PERSIST) &&
722 tun->dev->reg_state == NETREG_REGISTERED)
723 unregister_netdevice(tun->dev);
724 }
725 if (tun)
726 xdp_rxq_info_unreg(&tfile->xdp_rxq);
727 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
728 sock_put(&tfile->sk);
729 }
730 }
731
732 static void tun_detach(struct tun_file *tfile, bool clean)
733 {
734 struct tun_struct *tun;
735 struct net_device *dev;
736
737 rtnl_lock();
738 tun = rtnl_dereference(tfile->tun);
739 dev = tun ? tun->dev : NULL;
740 __tun_detach(tfile, clean);
741 if (dev)
742 netdev_state_change(dev);
743 rtnl_unlock();
744 }
745
746 static void tun_detach_all(struct net_device *dev)
747 {
748 struct tun_struct *tun = netdev_priv(dev);
749 struct tun_file *tfile, *tmp;
750 int i, n = tun->numqueues;
751
752 for (i = 0; i < n; i++) {
753 tfile = rtnl_dereference(tun->tfiles[i]);
754 BUG_ON(!tfile);
755 tun_napi_disable(tfile);
756 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
757 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
758 RCU_INIT_POINTER(tfile->tun, NULL);
759 --tun->numqueues;
760 }
761 list_for_each_entry(tfile, &tun->disabled, next) {
762 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
763 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
764 RCU_INIT_POINTER(tfile->tun, NULL);
765 }
766 BUG_ON(tun->numqueues != 0);
767
768 synchronize_net();
769 for (i = 0; i < n; i++) {
770 tfile = rtnl_dereference(tun->tfiles[i]);
771 tun_napi_del(tfile);
772 /* Drop read queue */
773 tun_queue_purge(tfile);
774 xdp_rxq_info_unreg(&tfile->xdp_rxq);
775 sock_put(&tfile->sk);
776 }
777 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
778 tun_enable_queue(tfile);
779 tun_queue_purge(tfile);
780 xdp_rxq_info_unreg(&tfile->xdp_rxq);
781 sock_put(&tfile->sk);
782 }
783 BUG_ON(tun->numdisabled != 0);
784
785 if (tun->flags & IFF_PERSIST)
786 module_put(THIS_MODULE);
787 }
788
789 static int tun_attach(struct tun_struct *tun, struct file *file,
790 bool skip_filter, bool napi, bool napi_frags,
791 bool publish_tun)
792 {
793 struct tun_file *tfile = file->private_data;
794 struct net_device *dev = tun->dev;
795 int err;
796
797 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
798 if (err < 0)
799 goto out;
800
801 err = -EINVAL;
802 if (rtnl_dereference(tfile->tun) && !tfile->detached)
803 goto out;
804
805 err = -EBUSY;
806 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
807 goto out;
808
809 err = -E2BIG;
810 if (!tfile->detached &&
811 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
812 goto out;
813
814 err = 0;
815
816 /* Re-attach the filter to persist device */
817 if (!skip_filter && (tun->filter_attached == true)) {
818 lock_sock(tfile->socket.sk);
819 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
820 release_sock(tfile->socket.sk);
821 if (!err)
822 goto out;
823 }
824
825 if (!tfile->detached &&
826 ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
827 GFP_KERNEL, tun_ptr_free)) {
828 err = -ENOMEM;
829 goto out;
830 }
831
832 tfile->queue_index = tun->numqueues;
833 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
834
835 if (tfile->detached) {
836 /* Re-attach detached tfile, updating XDP queue_index */
837 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
838
839 if (tfile->xdp_rxq.queue_index != tfile->queue_index)
840 tfile->xdp_rxq.queue_index = tfile->queue_index;
841 } else {
842 /* Setup XDP RX-queue info, for new tfile getting attached */
843 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
844 tun->dev, tfile->queue_index);
845 if (err < 0)
846 goto out;
847 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
848 MEM_TYPE_PAGE_SHARED, NULL);
849 if (err < 0) {
850 xdp_rxq_info_unreg(&tfile->xdp_rxq);
851 goto out;
852 }
853 err = 0;
854 }
855
856 if (tfile->detached) {
857 tun_enable_queue(tfile);
858 } else {
859 sock_hold(&tfile->sk);
860 tun_napi_init(tun, tfile, napi, napi_frags);
861 }
862
863 if (rtnl_dereference(tun->xdp_prog))
864 sock_set_flag(&tfile->sk, SOCK_XDP);
865
866 /* device is allowed to go away first, so no need to hold extra
867 * refcnt.
868 */
869
870 /* Publish tfile->tun and tun->tfiles only after we've fully
871 * initialized tfile; otherwise we risk using half-initialized
872 * object.
873 */
874 if (publish_tun)
875 rcu_assign_pointer(tfile->tun, tun);
876 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
877 tun->numqueues++;
878 tun_set_real_num_queues(tun);
879 out:
880 return err;
881 }
882
883 static struct tun_struct *tun_get(struct tun_file *tfile)
884 {
885 struct tun_struct *tun;
886
887 rcu_read_lock();
888 tun = rcu_dereference(tfile->tun);
889 if (tun)
890 dev_hold(tun->dev);
891 rcu_read_unlock();
892
893 return tun;
894 }
895
896 static void tun_put(struct tun_struct *tun)
897 {
898 dev_put(tun->dev);
899 }
900
901 /* TAP filtering */
902 static void addr_hash_set(u32 *mask, const u8 *addr)
903 {
904 int n = ether_crc(ETH_ALEN, addr) >> 26;
905 mask[n >> 5] |= (1 << (n & 31));
906 }
907
908 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
909 {
910 int n = ether_crc(ETH_ALEN, addr) >> 26;
911 return mask[n >> 5] & (1 << (n & 31));
912 }
913
914 static int update_filter(struct tap_filter *filter, void __user *arg)
915 {
916 struct { u8 u[ETH_ALEN]; } *addr;
917 struct tun_filter uf;
918 int err, alen, n, nexact;
919
920 if (copy_from_user(&uf, arg, sizeof(uf)))
921 return -EFAULT;
922
923 if (!uf.count) {
924 /* Disabled */
925 filter->count = 0;
926 return 0;
927 }
928
929 alen = ETH_ALEN * uf.count;
930 addr = memdup_user(arg + sizeof(uf), alen);
931 if (IS_ERR(addr))
932 return PTR_ERR(addr);
933
934 /* The filter is updated without holding any locks. Which is
935 * perfectly safe. We disable it first and in the worst
936 * case we'll accept a few undesired packets. */
937 filter->count = 0;
938 wmb();
939
940 /* Use first set of addresses as an exact filter */
941 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
942 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
943
944 nexact = n;
945
946 /* Remaining multicast addresses are hashed,
947 * unicast will leave the filter disabled. */
948 memset(filter->mask, 0, sizeof(filter->mask));
949 for (; n < uf.count; n++) {
950 if (!is_multicast_ether_addr(addr[n].u)) {
951 err = 0; /* no filter */
952 goto free_addr;
953 }
954 addr_hash_set(filter->mask, addr[n].u);
955 }
956
957 /* For ALLMULTI just set the mask to all ones.
958 * This overrides the mask populated above. */
959 if ((uf.flags & TUN_FLT_ALLMULTI))
960 memset(filter->mask, ~0, sizeof(filter->mask));
961
962 /* Now enable the filter */
963 wmb();
964 filter->count = nexact;
965
966 /* Return the number of exact filters */
967 err = nexact;
968 free_addr:
969 kfree(addr);
970 return err;
971 }
972
973 /* Returns: 0 - drop, !=0 - accept */
974 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
975 {
976 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
977 * at this point. */
978 struct ethhdr *eh = (struct ethhdr *) skb->data;
979 int i;
980
981 /* Exact match */
982 for (i = 0; i < filter->count; i++)
983 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
984 return 1;
985
986 /* Inexact match (multicast only) */
987 if (is_multicast_ether_addr(eh->h_dest))
988 return addr_hash_test(filter->mask, eh->h_dest);
989
990 return 0;
991 }
992
993 /*
994 * Checks whether the packet is accepted or not.
995 * Returns: 0 - drop, !=0 - accept
996 */
997 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
998 {
999 if (!filter->count)
1000 return 1;
1001
1002 return run_filter(filter, skb);
1003 }
1004
1005 /* Network device part of the driver */
1006
1007 static const struct ethtool_ops tun_ethtool_ops;
1008
1009 /* Net device detach from fd. */
1010 static void tun_net_uninit(struct net_device *dev)
1011 {
1012 tun_detach_all(dev);
1013 }
1014
1015 /* Net device open. */
1016 static int tun_net_open(struct net_device *dev)
1017 {
1018 netif_tx_start_all_queues(dev);
1019
1020 return 0;
1021 }
1022
1023 /* Net device close. */
1024 static int tun_net_close(struct net_device *dev)
1025 {
1026 netif_tx_stop_all_queues(dev);
1027 return 0;
1028 }
1029
1030 /* Net device start xmit */
1031 static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1032 {
1033 #ifdef CONFIG_RPS
1034 if (tun->numqueues == 1 && static_branch_unlikely(&rps_needed)) {
1035 /* Select queue was not called for the skbuff, so we extract the
1036 * RPS hash and save it into the flow_table here.
1037 */
1038 struct tun_flow_entry *e;
1039 __u32 rxhash;
1040
1041 rxhash = __skb_get_hash_symmetric(skb);
1042 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
1043 if (e)
1044 tun_flow_save_rps_rxhash(e, rxhash);
1045 }
1046 #endif
1047 }
1048
1049 static unsigned int run_ebpf_filter(struct tun_struct *tun,
1050 struct sk_buff *skb,
1051 int len)
1052 {
1053 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1054
1055 if (prog)
1056 len = bpf_prog_run_clear_cb(prog->prog, skb);
1057
1058 return len;
1059 }
1060
1061 /* Net device start xmit */
1062 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1063 {
1064 struct tun_struct *tun = netdev_priv(dev);
1065 int txq = skb->queue_mapping;
1066 struct tun_file *tfile;
1067 int len = skb->len;
1068
1069 rcu_read_lock();
1070 tfile = rcu_dereference(tun->tfiles[txq]);
1071
1072 /* Drop packet if interface is not attached */
1073 if (!tfile)
1074 goto drop;
1075
1076 if (!rcu_dereference(tun->steering_prog))
1077 tun_automq_xmit(tun, skb);
1078
1079 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
1080
1081 BUG_ON(!tfile);
1082
1083 /* Drop if the filter does not like it.
1084 * This is a noop if the filter is disabled.
1085 * Filter can be enabled only for the TAP devices. */
1086 if (!check_filter(&tun->txflt, skb))
1087 goto drop;
1088
1089 if (tfile->socket.sk->sk_filter &&
1090 sk_filter(tfile->socket.sk, skb))
1091 goto drop;
1092
1093 len = run_ebpf_filter(tun, skb, len);
1094 if (len == 0 || pskb_trim(skb, len))
1095 goto drop;
1096
1097 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1098 goto drop;
1099
1100 skb_tx_timestamp(skb);
1101
1102 /* Orphan the skb - required as we might hang on to it
1103 * for indefinite time.
1104 */
1105 skb_orphan(skb);
1106
1107 nf_reset_ct(skb);
1108
1109 if (ptr_ring_produce(&tfile->tx_ring, skb))
1110 goto drop;
1111
1112 /* Notify and wake up reader process */
1113 if (tfile->flags & TUN_FASYNC)
1114 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1115 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1116
1117 rcu_read_unlock();
1118 return NETDEV_TX_OK;
1119
1120 drop:
1121 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1122 skb_tx_error(skb);
1123 kfree_skb(skb);
1124 rcu_read_unlock();
1125 return NET_XMIT_DROP;
1126 }
1127
1128 static void tun_net_mclist(struct net_device *dev)
1129 {
1130 /*
1131 * This callback is supposed to deal with mc filter in
1132 * _rx_ path and has nothing to do with the _tx_ path.
1133 * In rx path we always accept everything userspace gives us.
1134 */
1135 }
1136
1137 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1138 netdev_features_t features)
1139 {
1140 struct tun_struct *tun = netdev_priv(dev);
1141
1142 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1143 }
1144
1145 static void tun_set_headroom(struct net_device *dev, int new_hr)
1146 {
1147 struct tun_struct *tun = netdev_priv(dev);
1148
1149 if (new_hr < NET_SKB_PAD)
1150 new_hr = NET_SKB_PAD;
1151
1152 tun->align = new_hr;
1153 }
1154
1155 static void
1156 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1157 {
1158 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1159 struct tun_struct *tun = netdev_priv(dev);
1160 struct tun_pcpu_stats *p;
1161 int i;
1162
1163 for_each_possible_cpu(i) {
1164 u64 rxpackets, rxbytes, txpackets, txbytes;
1165 unsigned int start;
1166
1167 p = per_cpu_ptr(tun->pcpu_stats, i);
1168 do {
1169 start = u64_stats_fetch_begin(&p->syncp);
1170 rxpackets = u64_stats_read(&p->rx_packets);
1171 rxbytes = u64_stats_read(&p->rx_bytes);
1172 txpackets = u64_stats_read(&p->tx_packets);
1173 txbytes = u64_stats_read(&p->tx_bytes);
1174 } while (u64_stats_fetch_retry(&p->syncp, start));
1175
1176 stats->rx_packets += rxpackets;
1177 stats->rx_bytes += rxbytes;
1178 stats->tx_packets += txpackets;
1179 stats->tx_bytes += txbytes;
1180
1181 /* u32 counters */
1182 rx_dropped += p->rx_dropped;
1183 rx_frame_errors += p->rx_frame_errors;
1184 tx_dropped += p->tx_dropped;
1185 }
1186 stats->rx_dropped = rx_dropped;
1187 stats->rx_frame_errors = rx_frame_errors;
1188 stats->tx_dropped = tx_dropped;
1189 }
1190
1191 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1192 struct netlink_ext_ack *extack)
1193 {
1194 struct tun_struct *tun = netdev_priv(dev);
1195 struct tun_file *tfile;
1196 struct bpf_prog *old_prog;
1197 int i;
1198
1199 old_prog = rtnl_dereference(tun->xdp_prog);
1200 rcu_assign_pointer(tun->xdp_prog, prog);
1201 if (old_prog)
1202 bpf_prog_put(old_prog);
1203
1204 for (i = 0; i < tun->numqueues; i++) {
1205 tfile = rtnl_dereference(tun->tfiles[i]);
1206 if (prog)
1207 sock_set_flag(&tfile->sk, SOCK_XDP);
1208 else
1209 sock_reset_flag(&tfile->sk, SOCK_XDP);
1210 }
1211 list_for_each_entry(tfile, &tun->disabled, next) {
1212 if (prog)
1213 sock_set_flag(&tfile->sk, SOCK_XDP);
1214 else
1215 sock_reset_flag(&tfile->sk, SOCK_XDP);
1216 }
1217
1218 return 0;
1219 }
1220
1221 static u32 tun_xdp_query(struct net_device *dev)
1222 {
1223 struct tun_struct *tun = netdev_priv(dev);
1224 const struct bpf_prog *xdp_prog;
1225
1226 xdp_prog = rtnl_dereference(tun->xdp_prog);
1227 if (xdp_prog)
1228 return xdp_prog->aux->id;
1229
1230 return 0;
1231 }
1232
1233 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1234 {
1235 switch (xdp->command) {
1236 case XDP_SETUP_PROG:
1237 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1238 case XDP_QUERY_PROG:
1239 xdp->prog_id = tun_xdp_query(dev);
1240 return 0;
1241 default:
1242 return -EINVAL;
1243 }
1244 }
1245
1246 static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1247 {
1248 if (new_carrier) {
1249 struct tun_struct *tun = netdev_priv(dev);
1250
1251 if (!tun->numqueues)
1252 return -EPERM;
1253
1254 netif_carrier_on(dev);
1255 } else {
1256 netif_carrier_off(dev);
1257 }
1258 return 0;
1259 }
1260
1261 static const struct net_device_ops tun_netdev_ops = {
1262 .ndo_uninit = tun_net_uninit,
1263 .ndo_open = tun_net_open,
1264 .ndo_stop = tun_net_close,
1265 .ndo_start_xmit = tun_net_xmit,
1266 .ndo_fix_features = tun_net_fix_features,
1267 .ndo_select_queue = tun_select_queue,
1268 .ndo_set_rx_headroom = tun_set_headroom,
1269 .ndo_get_stats64 = tun_net_get_stats64,
1270 .ndo_change_carrier = tun_net_change_carrier,
1271 };
1272
1273 static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1274 {
1275 /* Notify and wake up reader process */
1276 if (tfile->flags & TUN_FASYNC)
1277 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1278 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1279 }
1280
1281 static int tun_xdp_xmit(struct net_device *dev, int n,
1282 struct xdp_frame **frames, u32 flags)
1283 {
1284 struct tun_struct *tun = netdev_priv(dev);
1285 struct tun_file *tfile;
1286 u32 numqueues;
1287 int drops = 0;
1288 int cnt = n;
1289 int i;
1290
1291 if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1292 return -EINVAL;
1293
1294 rcu_read_lock();
1295
1296 resample:
1297 numqueues = READ_ONCE(tun->numqueues);
1298 if (!numqueues) {
1299 rcu_read_unlock();
1300 return -ENXIO; /* Caller will free/return all frames */
1301 }
1302
1303 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1304 numqueues]);
1305 if (unlikely(!tfile))
1306 goto resample;
1307
1308 spin_lock(&tfile->tx_ring.producer_lock);
1309 for (i = 0; i < n; i++) {
1310 struct xdp_frame *xdp = frames[i];
1311 /* Encode the XDP flag into lowest bit for consumer to differ
1312 * XDP buffer from sk_buff.
1313 */
1314 void *frame = tun_xdp_to_ptr(xdp);
1315
1316 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1317 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1318 xdp_return_frame_rx_napi(xdp);
1319 drops++;
1320 }
1321 }
1322 spin_unlock(&tfile->tx_ring.producer_lock);
1323
1324 if (flags & XDP_XMIT_FLUSH)
1325 __tun_xdp_flush_tfile(tfile);
1326
1327 rcu_read_unlock();
1328 return cnt - drops;
1329 }
1330
1331 static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1332 {
1333 struct xdp_frame *frame = convert_to_xdp_frame(xdp);
1334
1335 if (unlikely(!frame))
1336 return -EOVERFLOW;
1337
1338 return tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1339 }
1340
1341 static const struct net_device_ops tap_netdev_ops = {
1342 .ndo_uninit = tun_net_uninit,
1343 .ndo_open = tun_net_open,
1344 .ndo_stop = tun_net_close,
1345 .ndo_start_xmit = tun_net_xmit,
1346 .ndo_fix_features = tun_net_fix_features,
1347 .ndo_set_rx_mode = tun_net_mclist,
1348 .ndo_set_mac_address = eth_mac_addr,
1349 .ndo_validate_addr = eth_validate_addr,
1350 .ndo_select_queue = tun_select_queue,
1351 .ndo_features_check = passthru_features_check,
1352 .ndo_set_rx_headroom = tun_set_headroom,
1353 .ndo_get_stats64 = tun_net_get_stats64,
1354 .ndo_bpf = tun_xdp,
1355 .ndo_xdp_xmit = tun_xdp_xmit,
1356 .ndo_change_carrier = tun_net_change_carrier,
1357 };
1358
1359 static void tun_flow_init(struct tun_struct *tun)
1360 {
1361 int i;
1362
1363 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1364 INIT_HLIST_HEAD(&tun->flows[i]);
1365
1366 tun->ageing_time = TUN_FLOW_EXPIRE;
1367 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1368 mod_timer(&tun->flow_gc_timer,
1369 round_jiffies_up(jiffies + tun->ageing_time));
1370 }
1371
1372 static void tun_flow_uninit(struct tun_struct *tun)
1373 {
1374 del_timer_sync(&tun->flow_gc_timer);
1375 tun_flow_flush(tun);
1376 }
1377
1378 #define MIN_MTU 68
1379 #define MAX_MTU 65535
1380
1381 /* Initialize net device. */
1382 static void tun_net_init(struct net_device *dev)
1383 {
1384 struct tun_struct *tun = netdev_priv(dev);
1385
1386 switch (tun->flags & TUN_TYPE_MASK) {
1387 case IFF_TUN:
1388 dev->netdev_ops = &tun_netdev_ops;
1389
1390 /* Point-to-Point TUN Device */
1391 dev->hard_header_len = 0;
1392 dev->addr_len = 0;
1393 dev->mtu = 1500;
1394
1395 /* Zero header length */
1396 dev->type = ARPHRD_NONE;
1397 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1398 break;
1399
1400 case IFF_TAP:
1401 dev->netdev_ops = &tap_netdev_ops;
1402 /* Ethernet TAP Device */
1403 ether_setup(dev);
1404 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1405 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1406
1407 eth_hw_addr_random(dev);
1408
1409 break;
1410 }
1411
1412 dev->min_mtu = MIN_MTU;
1413 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1414 }
1415
1416 static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1417 {
1418 struct sock *sk = tfile->socket.sk;
1419
1420 return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1421 }
1422
1423 /* Character device part */
1424
1425 /* Poll */
1426 static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1427 {
1428 struct tun_file *tfile = file->private_data;
1429 struct tun_struct *tun = tun_get(tfile);
1430 struct sock *sk;
1431 __poll_t mask = 0;
1432
1433 if (!tun)
1434 return EPOLLERR;
1435
1436 sk = tfile->socket.sk;
1437
1438 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1439
1440 poll_wait(file, sk_sleep(sk), wait);
1441
1442 if (!ptr_ring_empty(&tfile->tx_ring))
1443 mask |= EPOLLIN | EPOLLRDNORM;
1444
1445 /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1446 * guarantee EPOLLOUT to be raised by either here or
1447 * tun_sock_write_space(). Then process could get notification
1448 * after it writes to a down device and meets -EIO.
1449 */
1450 if (tun_sock_writeable(tun, tfile) ||
1451 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1452 tun_sock_writeable(tun, tfile)))
1453 mask |= EPOLLOUT | EPOLLWRNORM;
1454
1455 if (tun->dev->reg_state != NETREG_REGISTERED)
1456 mask = EPOLLERR;
1457
1458 tun_put(tun);
1459 return mask;
1460 }
1461
1462 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1463 size_t len,
1464 const struct iov_iter *it)
1465 {
1466 struct sk_buff *skb;
1467 size_t linear;
1468 int err;
1469 int i;
1470
1471 if (it->nr_segs > MAX_SKB_FRAGS + 1)
1472 return ERR_PTR(-ENOMEM);
1473
1474 local_bh_disable();
1475 skb = napi_get_frags(&tfile->napi);
1476 local_bh_enable();
1477 if (!skb)
1478 return ERR_PTR(-ENOMEM);
1479
1480 linear = iov_iter_single_seg_count(it);
1481 err = __skb_grow(skb, linear);
1482 if (err)
1483 goto free;
1484
1485 skb->len = len;
1486 skb->data_len = len - linear;
1487 skb->truesize += skb->data_len;
1488
1489 for (i = 1; i < it->nr_segs; i++) {
1490 size_t fragsz = it->iov[i].iov_len;
1491 struct page *page;
1492 void *frag;
1493
1494 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1495 err = -EINVAL;
1496 goto free;
1497 }
1498 frag = netdev_alloc_frag(fragsz);
1499 if (!frag) {
1500 err = -ENOMEM;
1501 goto free;
1502 }
1503 page = virt_to_head_page(frag);
1504 skb_fill_page_desc(skb, i - 1, page,
1505 frag - page_address(page), fragsz);
1506 }
1507
1508 return skb;
1509 free:
1510 /* frees skb and all frags allocated with napi_alloc_frag() */
1511 napi_free_frags(&tfile->napi);
1512 return ERR_PTR(err);
1513 }
1514
1515 /* prepad is the amount to reserve at front. len is length after that.
1516 * linear is a hint as to how much to copy (usually headers). */
1517 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1518 size_t prepad, size_t len,
1519 size_t linear, int noblock)
1520 {
1521 struct sock *sk = tfile->socket.sk;
1522 struct sk_buff *skb;
1523 int err;
1524
1525 /* Under a page? Don't bother with paged skb. */
1526 if (prepad + len < PAGE_SIZE || !linear)
1527 linear = len;
1528
1529 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1530 &err, 0);
1531 if (!skb)
1532 return ERR_PTR(err);
1533
1534 skb_reserve(skb, prepad);
1535 skb_put(skb, linear);
1536 skb->data_len = len - linear;
1537 skb->len += len - linear;
1538
1539 return skb;
1540 }
1541
1542 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1543 struct sk_buff *skb, int more)
1544 {
1545 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1546 struct sk_buff_head process_queue;
1547 u32 rx_batched = tun->rx_batched;
1548 bool rcv = false;
1549
1550 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1551 local_bh_disable();
1552 skb_record_rx_queue(skb, tfile->queue_index);
1553 netif_receive_skb(skb);
1554 local_bh_enable();
1555 return;
1556 }
1557
1558 spin_lock(&queue->lock);
1559 if (!more || skb_queue_len(queue) == rx_batched) {
1560 __skb_queue_head_init(&process_queue);
1561 skb_queue_splice_tail_init(queue, &process_queue);
1562 rcv = true;
1563 } else {
1564 __skb_queue_tail(queue, skb);
1565 }
1566 spin_unlock(&queue->lock);
1567
1568 if (rcv) {
1569 struct sk_buff *nskb;
1570
1571 local_bh_disable();
1572 while ((nskb = __skb_dequeue(&process_queue))) {
1573 skb_record_rx_queue(nskb, tfile->queue_index);
1574 netif_receive_skb(nskb);
1575 }
1576 skb_record_rx_queue(skb, tfile->queue_index);
1577 netif_receive_skb(skb);
1578 local_bh_enable();
1579 }
1580 }
1581
1582 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1583 int len, int noblock, bool zerocopy)
1584 {
1585 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1586 return false;
1587
1588 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1589 return false;
1590
1591 if (!noblock)
1592 return false;
1593
1594 if (zerocopy)
1595 return false;
1596
1597 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1598 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1599 return false;
1600
1601 return true;
1602 }
1603
1604 static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
1605 struct page_frag *alloc_frag, char *buf,
1606 int buflen, int len, int pad)
1607 {
1608 struct sk_buff *skb = build_skb(buf, buflen);
1609
1610 if (!skb)
1611 return ERR_PTR(-ENOMEM);
1612
1613 skb_reserve(skb, pad);
1614 skb_put(skb, len);
1615 skb_set_owner_w(skb, tfile->socket.sk);
1616
1617 get_page(alloc_frag->page);
1618 alloc_frag->offset += buflen;
1619
1620 return skb;
1621 }
1622
1623 static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1624 struct xdp_buff *xdp, u32 act)
1625 {
1626 int err;
1627
1628 switch (act) {
1629 case XDP_REDIRECT:
1630 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1631 if (err)
1632 return err;
1633 break;
1634 case XDP_TX:
1635 err = tun_xdp_tx(tun->dev, xdp);
1636 if (err < 0)
1637 return err;
1638 break;
1639 case XDP_PASS:
1640 break;
1641 default:
1642 bpf_warn_invalid_xdp_action(act);
1643 /* fall through */
1644 case XDP_ABORTED:
1645 trace_xdp_exception(tun->dev, xdp_prog, act);
1646 /* fall through */
1647 case XDP_DROP:
1648 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1649 break;
1650 }
1651
1652 return act;
1653 }
1654
1655 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1656 struct tun_file *tfile,
1657 struct iov_iter *from,
1658 struct virtio_net_hdr *hdr,
1659 int len, int *skb_xdp)
1660 {
1661 struct page_frag *alloc_frag = &current->task_frag;
1662 struct bpf_prog *xdp_prog;
1663 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1664 char *buf;
1665 size_t copied;
1666 int pad = TUN_RX_PAD;
1667 int err = 0;
1668
1669 rcu_read_lock();
1670 xdp_prog = rcu_dereference(tun->xdp_prog);
1671 if (xdp_prog)
1672 pad += XDP_PACKET_HEADROOM;
1673 buflen += SKB_DATA_ALIGN(len + pad);
1674 rcu_read_unlock();
1675
1676 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1677 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1678 return ERR_PTR(-ENOMEM);
1679
1680 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1681 copied = copy_page_from_iter(alloc_frag->page,
1682 alloc_frag->offset + pad,
1683 len, from);
1684 if (copied != len)
1685 return ERR_PTR(-EFAULT);
1686
1687 /* There's a small window that XDP may be set after the check
1688 * of xdp_prog above, this should be rare and for simplicity
1689 * we do XDP on skb in case the headroom is not enough.
1690 */
1691 if (hdr->gso_type || !xdp_prog) {
1692 *skb_xdp = 1;
1693 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len,
1694 pad);
1695 }
1696
1697 *skb_xdp = 0;
1698
1699 local_bh_disable();
1700 rcu_read_lock();
1701 xdp_prog = rcu_dereference(tun->xdp_prog);
1702 if (xdp_prog) {
1703 struct xdp_buff xdp;
1704 u32 act;
1705
1706 xdp.data_hard_start = buf;
1707 xdp.data = buf + pad;
1708 xdp_set_data_meta_invalid(&xdp);
1709 xdp.data_end = xdp.data + len;
1710 xdp.rxq = &tfile->xdp_rxq;
1711
1712 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1713 if (act == XDP_REDIRECT || act == XDP_TX) {
1714 get_page(alloc_frag->page);
1715 alloc_frag->offset += buflen;
1716 }
1717 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1718 if (err < 0)
1719 goto err_xdp;
1720 if (err == XDP_REDIRECT)
1721 xdp_do_flush();
1722 if (err != XDP_PASS)
1723 goto out;
1724
1725 pad = xdp.data - xdp.data_hard_start;
1726 len = xdp.data_end - xdp.data;
1727 }
1728 rcu_read_unlock();
1729 local_bh_enable();
1730
1731 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1732
1733 err_xdp:
1734 put_page(alloc_frag->page);
1735 out:
1736 rcu_read_unlock();
1737 local_bh_enable();
1738 return NULL;
1739 }
1740
1741 /* Get packet from user space buffer */
1742 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1743 void *msg_control, struct iov_iter *from,
1744 int noblock, bool more)
1745 {
1746 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1747 struct sk_buff *skb;
1748 size_t total_len = iov_iter_count(from);
1749 size_t len = total_len, align = tun->align, linear;
1750 struct virtio_net_hdr gso = { 0 };
1751 struct tun_pcpu_stats *stats;
1752 int good_linear;
1753 int copylen;
1754 bool zerocopy = false;
1755 int err;
1756 u32 rxhash = 0;
1757 int skb_xdp = 1;
1758 bool frags = tun_napi_frags_enabled(tfile);
1759
1760 if (!(tun->flags & IFF_NO_PI)) {
1761 if (len < sizeof(pi))
1762 return -EINVAL;
1763 len -= sizeof(pi);
1764
1765 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1766 return -EFAULT;
1767 }
1768
1769 if (tun->flags & IFF_VNET_HDR) {
1770 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1771
1772 if (len < vnet_hdr_sz)
1773 return -EINVAL;
1774 len -= vnet_hdr_sz;
1775
1776 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1777 return -EFAULT;
1778
1779 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1780 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1781 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1782
1783 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1784 return -EINVAL;
1785 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1786 }
1787
1788 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1789 align += NET_IP_ALIGN;
1790 if (unlikely(len < ETH_HLEN ||
1791 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1792 return -EINVAL;
1793 }
1794
1795 good_linear = SKB_MAX_HEAD(align);
1796
1797 if (msg_control) {
1798 struct iov_iter i = *from;
1799
1800 /* There are 256 bytes to be copied in skb, so there is
1801 * enough room for skb expand head in case it is used.
1802 * The rest of the buffer is mapped from userspace.
1803 */
1804 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1805 if (copylen > good_linear)
1806 copylen = good_linear;
1807 linear = copylen;
1808 iov_iter_advance(&i, copylen);
1809 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1810 zerocopy = true;
1811 }
1812
1813 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1814 /* For the packet that is not easy to be processed
1815 * (e.g gso or jumbo packet), we will do it at after
1816 * skb was created with generic XDP routine.
1817 */
1818 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1819 if (IS_ERR(skb)) {
1820 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1821 return PTR_ERR(skb);
1822 }
1823 if (!skb)
1824 return total_len;
1825 } else {
1826 if (!zerocopy) {
1827 copylen = len;
1828 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1829 linear = good_linear;
1830 else
1831 linear = tun16_to_cpu(tun, gso.hdr_len);
1832 }
1833
1834 if (frags) {
1835 mutex_lock(&tfile->napi_mutex);
1836 skb = tun_napi_alloc_frags(tfile, copylen, from);
1837 /* tun_napi_alloc_frags() enforces a layout for the skb.
1838 * If zerocopy is enabled, then this layout will be
1839 * overwritten by zerocopy_sg_from_iter().
1840 */
1841 zerocopy = false;
1842 } else {
1843 skb = tun_alloc_skb(tfile, align, copylen, linear,
1844 noblock);
1845 }
1846
1847 if (IS_ERR(skb)) {
1848 if (PTR_ERR(skb) != -EAGAIN)
1849 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1850 if (frags)
1851 mutex_unlock(&tfile->napi_mutex);
1852 return PTR_ERR(skb);
1853 }
1854
1855 if (zerocopy)
1856 err = zerocopy_sg_from_iter(skb, from);
1857 else
1858 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1859
1860 if (err) {
1861 err = -EFAULT;
1862 drop:
1863 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1864 kfree_skb(skb);
1865 if (frags) {
1866 tfile->napi.skb = NULL;
1867 mutex_unlock(&tfile->napi_mutex);
1868 }
1869
1870 return err;
1871 }
1872 }
1873
1874 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1875 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1876 kfree_skb(skb);
1877 if (frags) {
1878 tfile->napi.skb = NULL;
1879 mutex_unlock(&tfile->napi_mutex);
1880 }
1881
1882 return -EINVAL;
1883 }
1884
1885 switch (tun->flags & TUN_TYPE_MASK) {
1886 case IFF_TUN:
1887 if (tun->flags & IFF_NO_PI) {
1888 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1889
1890 switch (ip_version) {
1891 case 4:
1892 pi.proto = htons(ETH_P_IP);
1893 break;
1894 case 6:
1895 pi.proto = htons(ETH_P_IPV6);
1896 break;
1897 default:
1898 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1899 kfree_skb(skb);
1900 return -EINVAL;
1901 }
1902 }
1903
1904 skb_reset_mac_header(skb);
1905 skb->protocol = pi.proto;
1906 skb->dev = tun->dev;
1907 break;
1908 case IFF_TAP:
1909 if (!frags)
1910 skb->protocol = eth_type_trans(skb, tun->dev);
1911 break;
1912 }
1913
1914 /* copy skb_ubuf_info for callback when skb has no error */
1915 if (zerocopy) {
1916 skb_shinfo(skb)->destructor_arg = msg_control;
1917 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1918 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1919 } else if (msg_control) {
1920 struct ubuf_info *uarg = msg_control;
1921 uarg->callback(uarg, false);
1922 }
1923
1924 skb_reset_network_header(skb);
1925 skb_probe_transport_header(skb);
1926
1927 if (skb_xdp) {
1928 struct bpf_prog *xdp_prog;
1929 int ret;
1930
1931 local_bh_disable();
1932 rcu_read_lock();
1933 xdp_prog = rcu_dereference(tun->xdp_prog);
1934 if (xdp_prog) {
1935 ret = do_xdp_generic(xdp_prog, skb);
1936 if (ret != XDP_PASS) {
1937 rcu_read_unlock();
1938 local_bh_enable();
1939 if (frags) {
1940 tfile->napi.skb = NULL;
1941 mutex_unlock(&tfile->napi_mutex);
1942 }
1943 return total_len;
1944 }
1945 }
1946 rcu_read_unlock();
1947 local_bh_enable();
1948 }
1949
1950 /* Compute the costly rx hash only if needed for flow updates.
1951 * We may get a very small possibility of OOO during switching, not
1952 * worth to optimize.
1953 */
1954 if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1955 !tfile->detached)
1956 rxhash = __skb_get_hash_symmetric(skb);
1957
1958 rcu_read_lock();
1959 if (unlikely(!(tun->dev->flags & IFF_UP))) {
1960 err = -EIO;
1961 rcu_read_unlock();
1962 goto drop;
1963 }
1964
1965 if (frags) {
1966 /* Exercise flow dissector code path. */
1967 u32 headlen = eth_get_headlen(tun->dev, skb->data,
1968 skb_headlen(skb));
1969
1970 if (unlikely(headlen > skb_headlen(skb))) {
1971 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1972 napi_free_frags(&tfile->napi);
1973 rcu_read_unlock();
1974 mutex_unlock(&tfile->napi_mutex);
1975 WARN_ON(1);
1976 return -ENOMEM;
1977 }
1978
1979 local_bh_disable();
1980 napi_gro_frags(&tfile->napi);
1981 local_bh_enable();
1982 mutex_unlock(&tfile->napi_mutex);
1983 } else if (tfile->napi_enabled) {
1984 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1985 int queue_len;
1986
1987 spin_lock_bh(&queue->lock);
1988 __skb_queue_tail(queue, skb);
1989 queue_len = skb_queue_len(queue);
1990 spin_unlock(&queue->lock);
1991
1992 if (!more || queue_len > NAPI_POLL_WEIGHT)
1993 napi_schedule(&tfile->napi);
1994
1995 local_bh_enable();
1996 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1997 tun_rx_batched(tun, tfile, skb, more);
1998 } else {
1999 netif_rx_ni(skb);
2000 }
2001 rcu_read_unlock();
2002
2003 stats = get_cpu_ptr(tun->pcpu_stats);
2004 u64_stats_update_begin(&stats->syncp);
2005 u64_stats_inc(&stats->rx_packets);
2006 u64_stats_add(&stats->rx_bytes, len);
2007 u64_stats_update_end(&stats->syncp);
2008 put_cpu_ptr(stats);
2009
2010 if (rxhash)
2011 tun_flow_update(tun, rxhash, tfile);
2012
2013 return total_len;
2014 }
2015
2016 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
2017 {
2018 struct file *file = iocb->ki_filp;
2019 struct tun_file *tfile = file->private_data;
2020 struct tun_struct *tun = tun_get(tfile);
2021 ssize_t result;
2022
2023 if (!tun)
2024 return -EBADFD;
2025
2026 result = tun_get_user(tun, tfile, NULL, from,
2027 file->f_flags & O_NONBLOCK, false);
2028
2029 tun_put(tun);
2030 return result;
2031 }
2032
2033 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2034 struct tun_file *tfile,
2035 struct xdp_frame *xdp_frame,
2036 struct iov_iter *iter)
2037 {
2038 int vnet_hdr_sz = 0;
2039 size_t size = xdp_frame->len;
2040 struct tun_pcpu_stats *stats;
2041 size_t ret;
2042
2043 if (tun->flags & IFF_VNET_HDR) {
2044 struct virtio_net_hdr gso = { 0 };
2045
2046 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2047 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2048 return -EINVAL;
2049 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2050 sizeof(gso)))
2051 return -EFAULT;
2052 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2053 }
2054
2055 ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2056
2057 stats = get_cpu_ptr(tun->pcpu_stats);
2058 u64_stats_update_begin(&stats->syncp);
2059 u64_stats_inc(&stats->tx_packets);
2060 u64_stats_add(&stats->tx_bytes, ret);
2061 u64_stats_update_end(&stats->syncp);
2062 put_cpu_ptr(tun->pcpu_stats);
2063
2064 return ret;
2065 }
2066
2067 /* Put packet to the user space buffer */
2068 static ssize_t tun_put_user(struct tun_struct *tun,
2069 struct tun_file *tfile,
2070 struct sk_buff *skb,
2071 struct iov_iter *iter)
2072 {
2073 struct tun_pi pi = { 0, skb->protocol };
2074 struct tun_pcpu_stats *stats;
2075 ssize_t total;
2076 int vlan_offset = 0;
2077 int vlan_hlen = 0;
2078 int vnet_hdr_sz = 0;
2079
2080 if (skb_vlan_tag_present(skb))
2081 vlan_hlen = VLAN_HLEN;
2082
2083 if (tun->flags & IFF_VNET_HDR)
2084 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2085
2086 total = skb->len + vlan_hlen + vnet_hdr_sz;
2087
2088 if (!(tun->flags & IFF_NO_PI)) {
2089 if (iov_iter_count(iter) < sizeof(pi))
2090 return -EINVAL;
2091
2092 total += sizeof(pi);
2093 if (iov_iter_count(iter) < total) {
2094 /* Packet will be striped */
2095 pi.flags |= TUN_PKT_STRIP;
2096 }
2097
2098 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2099 return -EFAULT;
2100 }
2101
2102 if (vnet_hdr_sz) {
2103 struct virtio_net_hdr gso;
2104
2105 if (iov_iter_count(iter) < vnet_hdr_sz)
2106 return -EINVAL;
2107
2108 if (virtio_net_hdr_from_skb(skb, &gso,
2109 tun_is_little_endian(tun), true,
2110 vlan_hlen)) {
2111 struct skb_shared_info *sinfo = skb_shinfo(skb);
2112 pr_err("unexpected GSO type: "
2113 "0x%x, gso_size %d, hdr_len %d\n",
2114 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2115 tun16_to_cpu(tun, gso.hdr_len));
2116 print_hex_dump(KERN_ERR, "tun: ",
2117 DUMP_PREFIX_NONE,
2118 16, 1, skb->head,
2119 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2120 WARN_ON_ONCE(1);
2121 return -EINVAL;
2122 }
2123
2124 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2125 return -EFAULT;
2126
2127 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2128 }
2129
2130 if (vlan_hlen) {
2131 int ret;
2132 struct veth veth;
2133
2134 veth.h_vlan_proto = skb->vlan_proto;
2135 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2136
2137 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2138
2139 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2140 if (ret || !iov_iter_count(iter))
2141 goto done;
2142
2143 ret = copy_to_iter(&veth, sizeof(veth), iter);
2144 if (ret != sizeof(veth) || !iov_iter_count(iter))
2145 goto done;
2146 }
2147
2148 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2149
2150 done:
2151 /* caller is in process context, */
2152 stats = get_cpu_ptr(tun->pcpu_stats);
2153 u64_stats_update_begin(&stats->syncp);
2154 u64_stats_inc(&stats->tx_packets);
2155 u64_stats_add(&stats->tx_bytes, skb->len + vlan_hlen);
2156 u64_stats_update_end(&stats->syncp);
2157 put_cpu_ptr(tun->pcpu_stats);
2158
2159 return total;
2160 }
2161
2162 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2163 {
2164 DECLARE_WAITQUEUE(wait, current);
2165 void *ptr = NULL;
2166 int error = 0;
2167
2168 ptr = ptr_ring_consume(&tfile->tx_ring);
2169 if (ptr)
2170 goto out;
2171 if (noblock) {
2172 error = -EAGAIN;
2173 goto out;
2174 }
2175
2176 add_wait_queue(&tfile->socket.wq.wait, &wait);
2177
2178 while (1) {
2179 set_current_state(TASK_INTERRUPTIBLE);
2180 ptr = ptr_ring_consume(&tfile->tx_ring);
2181 if (ptr)
2182 break;
2183 if (signal_pending(current)) {
2184 error = -ERESTARTSYS;
2185 break;
2186 }
2187 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2188 error = -EFAULT;
2189 break;
2190 }
2191
2192 schedule();
2193 }
2194
2195 __set_current_state(TASK_RUNNING);
2196 remove_wait_queue(&tfile->socket.wq.wait, &wait);
2197
2198 out:
2199 *err = error;
2200 return ptr;
2201 }
2202
2203 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2204 struct iov_iter *to,
2205 int noblock, void *ptr)
2206 {
2207 ssize_t ret;
2208 int err;
2209
2210 tun_debug(KERN_INFO, tun, "tun_do_read\n");
2211
2212 if (!iov_iter_count(to)) {
2213 tun_ptr_free(ptr);
2214 return 0;
2215 }
2216
2217 if (!ptr) {
2218 /* Read frames from ring */
2219 ptr = tun_ring_recv(tfile, noblock, &err);
2220 if (!ptr)
2221 return err;
2222 }
2223
2224 if (tun_is_xdp_frame(ptr)) {
2225 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2226
2227 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2228 xdp_return_frame(xdpf);
2229 } else {
2230 struct sk_buff *skb = ptr;
2231
2232 ret = tun_put_user(tun, tfile, skb, to);
2233 if (unlikely(ret < 0))
2234 kfree_skb(skb);
2235 else
2236 consume_skb(skb);
2237 }
2238
2239 return ret;
2240 }
2241
2242 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2243 {
2244 struct file *file = iocb->ki_filp;
2245 struct tun_file *tfile = file->private_data;
2246 struct tun_struct *tun = tun_get(tfile);
2247 ssize_t len = iov_iter_count(to), ret;
2248
2249 if (!tun)
2250 return -EBADFD;
2251 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2252 ret = min_t(ssize_t, ret, len);
2253 if (ret > 0)
2254 iocb->ki_pos = ret;
2255 tun_put(tun);
2256 return ret;
2257 }
2258
2259 static void tun_prog_free(struct rcu_head *rcu)
2260 {
2261 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2262
2263 bpf_prog_destroy(prog->prog);
2264 kfree(prog);
2265 }
2266
2267 static int __tun_set_ebpf(struct tun_struct *tun,
2268 struct tun_prog __rcu **prog_p,
2269 struct bpf_prog *prog)
2270 {
2271 struct tun_prog *old, *new = NULL;
2272
2273 if (prog) {
2274 new = kmalloc(sizeof(*new), GFP_KERNEL);
2275 if (!new)
2276 return -ENOMEM;
2277 new->prog = prog;
2278 }
2279
2280 spin_lock_bh(&tun->lock);
2281 old = rcu_dereference_protected(*prog_p,
2282 lockdep_is_held(&tun->lock));
2283 rcu_assign_pointer(*prog_p, new);
2284 spin_unlock_bh(&tun->lock);
2285
2286 if (old)
2287 call_rcu(&old->rcu, tun_prog_free);
2288
2289 return 0;
2290 }
2291
2292 static void tun_free_netdev(struct net_device *dev)
2293 {
2294 struct tun_struct *tun = netdev_priv(dev);
2295
2296 BUG_ON(!(list_empty(&tun->disabled)));
2297
2298 free_percpu(tun->pcpu_stats);
2299 /* We clear pcpu_stats so that tun_set_iff() can tell if
2300 * tun_free_netdev() has been called from register_netdevice().
2301 */
2302 tun->pcpu_stats = NULL;
2303
2304 tun_flow_uninit(tun);
2305 security_tun_dev_free_security(tun->security);
2306 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2307 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2308 }
2309
2310 static void tun_setup(struct net_device *dev)
2311 {
2312 struct tun_struct *tun = netdev_priv(dev);
2313
2314 tun->owner = INVALID_UID;
2315 tun->group = INVALID_GID;
2316 tun_default_link_ksettings(dev, &tun->link_ksettings);
2317
2318 dev->ethtool_ops = &tun_ethtool_ops;
2319 dev->needs_free_netdev = true;
2320 dev->priv_destructor = tun_free_netdev;
2321 /* We prefer our own queue length */
2322 dev->tx_queue_len = TUN_READQ_SIZE;
2323 }
2324
2325 /* Trivial set of netlink ops to allow deleting tun or tap
2326 * device with netlink.
2327 */
2328 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2329 struct netlink_ext_ack *extack)
2330 {
2331 NL_SET_ERR_MSG(extack,
2332 "tun/tap creation via rtnetlink is not supported.");
2333 return -EOPNOTSUPP;
2334 }
2335
2336 static size_t tun_get_size(const struct net_device *dev)
2337 {
2338 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2339 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2340
2341 return nla_total_size(sizeof(uid_t)) + /* OWNER */
2342 nla_total_size(sizeof(gid_t)) + /* GROUP */
2343 nla_total_size(sizeof(u8)) + /* TYPE */
2344 nla_total_size(sizeof(u8)) + /* PI */
2345 nla_total_size(sizeof(u8)) + /* VNET_HDR */
2346 nla_total_size(sizeof(u8)) + /* PERSIST */
2347 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2348 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2349 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2350 0;
2351 }
2352
2353 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2354 {
2355 struct tun_struct *tun = netdev_priv(dev);
2356
2357 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2358 goto nla_put_failure;
2359 if (uid_valid(tun->owner) &&
2360 nla_put_u32(skb, IFLA_TUN_OWNER,
2361 from_kuid_munged(current_user_ns(), tun->owner)))
2362 goto nla_put_failure;
2363 if (gid_valid(tun->group) &&
2364 nla_put_u32(skb, IFLA_TUN_GROUP,
2365 from_kgid_munged(current_user_ns(), tun->group)))
2366 goto nla_put_failure;
2367 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2368 goto nla_put_failure;
2369 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2370 goto nla_put_failure;
2371 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2372 goto nla_put_failure;
2373 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2374 !!(tun->flags & IFF_MULTI_QUEUE)))
2375 goto nla_put_failure;
2376 if (tun->flags & IFF_MULTI_QUEUE) {
2377 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2378 goto nla_put_failure;
2379 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2380 tun->numdisabled))
2381 goto nla_put_failure;
2382 }
2383
2384 return 0;
2385
2386 nla_put_failure:
2387 return -EMSGSIZE;
2388 }
2389
2390 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2391 .kind = DRV_NAME,
2392 .priv_size = sizeof(struct tun_struct),
2393 .setup = tun_setup,
2394 .validate = tun_validate,
2395 .get_size = tun_get_size,
2396 .fill_info = tun_fill_info,
2397 };
2398
2399 static void tun_sock_write_space(struct sock *sk)
2400 {
2401 struct tun_file *tfile;
2402 wait_queue_head_t *wqueue;
2403
2404 if (!sock_writeable(sk))
2405 return;
2406
2407 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2408 return;
2409
2410 wqueue = sk_sleep(sk);
2411 if (wqueue && waitqueue_active(wqueue))
2412 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2413 EPOLLWRNORM | EPOLLWRBAND);
2414
2415 tfile = container_of(sk, struct tun_file, sk);
2416 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2417 }
2418
2419 static void tun_put_page(struct tun_page *tpage)
2420 {
2421 if (tpage->page)
2422 __page_frag_cache_drain(tpage->page, tpage->count);
2423 }
2424
2425 static int tun_xdp_one(struct tun_struct *tun,
2426 struct tun_file *tfile,
2427 struct xdp_buff *xdp, int *flush,
2428 struct tun_page *tpage)
2429 {
2430 unsigned int datasize = xdp->data_end - xdp->data;
2431 struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2432 struct virtio_net_hdr *gso = &hdr->gso;
2433 struct tun_pcpu_stats *stats;
2434 struct bpf_prog *xdp_prog;
2435 struct sk_buff *skb = NULL;
2436 u32 rxhash = 0, act;
2437 int buflen = hdr->buflen;
2438 int err = 0;
2439 bool skb_xdp = false;
2440 struct page *page;
2441
2442 xdp_prog = rcu_dereference(tun->xdp_prog);
2443 if (xdp_prog) {
2444 if (gso->gso_type) {
2445 skb_xdp = true;
2446 goto build;
2447 }
2448 xdp_set_data_meta_invalid(xdp);
2449 xdp->rxq = &tfile->xdp_rxq;
2450
2451 act = bpf_prog_run_xdp(xdp_prog, xdp);
2452 err = tun_xdp_act(tun, xdp_prog, xdp, act);
2453 if (err < 0) {
2454 put_page(virt_to_head_page(xdp->data));
2455 return err;
2456 }
2457
2458 switch (err) {
2459 case XDP_REDIRECT:
2460 *flush = true;
2461 /* fall through */
2462 case XDP_TX:
2463 return 0;
2464 case XDP_PASS:
2465 break;
2466 default:
2467 page = virt_to_head_page(xdp->data);
2468 if (tpage->page == page) {
2469 ++tpage->count;
2470 } else {
2471 tun_put_page(tpage);
2472 tpage->page = page;
2473 tpage->count = 1;
2474 }
2475 return 0;
2476 }
2477 }
2478
2479 build:
2480 skb = build_skb(xdp->data_hard_start, buflen);
2481 if (!skb) {
2482 err = -ENOMEM;
2483 goto out;
2484 }
2485
2486 skb_reserve(skb, xdp->data - xdp->data_hard_start);
2487 skb_put(skb, xdp->data_end - xdp->data);
2488
2489 if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2490 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
2491 kfree_skb(skb);
2492 err = -EINVAL;
2493 goto out;
2494 }
2495
2496 skb->protocol = eth_type_trans(skb, tun->dev);
2497 skb_reset_network_header(skb);
2498 skb_probe_transport_header(skb);
2499
2500 if (skb_xdp) {
2501 err = do_xdp_generic(xdp_prog, skb);
2502 if (err != XDP_PASS)
2503 goto out;
2504 }
2505
2506 if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2507 !tfile->detached)
2508 rxhash = __skb_get_hash_symmetric(skb);
2509
2510 skb_record_rx_queue(skb, tfile->queue_index);
2511 netif_receive_skb(skb);
2512
2513 /* No need for get_cpu_ptr() here since this function is
2514 * always called with bh disabled
2515 */
2516 stats = this_cpu_ptr(tun->pcpu_stats);
2517 u64_stats_update_begin(&stats->syncp);
2518 u64_stats_inc(&stats->rx_packets);
2519 u64_stats_add(&stats->rx_bytes, datasize);
2520 u64_stats_update_end(&stats->syncp);
2521
2522 if (rxhash)
2523 tun_flow_update(tun, rxhash, tfile);
2524
2525 out:
2526 return err;
2527 }
2528
2529 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2530 {
2531 int ret, i;
2532 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2533 struct tun_struct *tun = tun_get(tfile);
2534 struct tun_msg_ctl *ctl = m->msg_control;
2535 struct xdp_buff *xdp;
2536
2537 if (!tun)
2538 return -EBADFD;
2539
2540 if (ctl && (ctl->type == TUN_MSG_PTR)) {
2541 struct tun_page tpage;
2542 int n = ctl->num;
2543 int flush = 0;
2544
2545 memset(&tpage, 0, sizeof(tpage));
2546
2547 local_bh_disable();
2548 rcu_read_lock();
2549
2550 for (i = 0; i < n; i++) {
2551 xdp = &((struct xdp_buff *)ctl->ptr)[i];
2552 tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2553 }
2554
2555 if (flush)
2556 xdp_do_flush();
2557
2558 rcu_read_unlock();
2559 local_bh_enable();
2560
2561 tun_put_page(&tpage);
2562
2563 ret = total_len;
2564 goto out;
2565 }
2566
2567 ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2568 m->msg_flags & MSG_DONTWAIT,
2569 m->msg_flags & MSG_MORE);
2570 out:
2571 tun_put(tun);
2572 return ret;
2573 }
2574
2575 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2576 int flags)
2577 {
2578 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2579 struct tun_struct *tun = tun_get(tfile);
2580 void *ptr = m->msg_control;
2581 int ret;
2582
2583 if (!tun) {
2584 ret = -EBADFD;
2585 goto out_free;
2586 }
2587
2588 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2589 ret = -EINVAL;
2590 goto out_put_tun;
2591 }
2592 if (flags & MSG_ERRQUEUE) {
2593 ret = sock_recv_errqueue(sock->sk, m, total_len,
2594 SOL_PACKET, TUN_TX_TIMESTAMP);
2595 goto out;
2596 }
2597 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2598 if (ret > (ssize_t)total_len) {
2599 m->msg_flags |= MSG_TRUNC;
2600 ret = flags & MSG_TRUNC ? ret : total_len;
2601 }
2602 out:
2603 tun_put(tun);
2604 return ret;
2605
2606 out_put_tun:
2607 tun_put(tun);
2608 out_free:
2609 tun_ptr_free(ptr);
2610 return ret;
2611 }
2612
2613 static int tun_ptr_peek_len(void *ptr)
2614 {
2615 if (likely(ptr)) {
2616 if (tun_is_xdp_frame(ptr)) {
2617 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2618
2619 return xdpf->len;
2620 }
2621 return __skb_array_len_with_tag(ptr);
2622 } else {
2623 return 0;
2624 }
2625 }
2626
2627 static int tun_peek_len(struct socket *sock)
2628 {
2629 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2630 struct tun_struct *tun;
2631 int ret = 0;
2632
2633 tun = tun_get(tfile);
2634 if (!tun)
2635 return 0;
2636
2637 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2638 tun_put(tun);
2639
2640 return ret;
2641 }
2642
2643 /* Ops structure to mimic raw sockets with tun */
2644 static const struct proto_ops tun_socket_ops = {
2645 .peek_len = tun_peek_len,
2646 .sendmsg = tun_sendmsg,
2647 .recvmsg = tun_recvmsg,
2648 };
2649
2650 static struct proto tun_proto = {
2651 .name = "tun",
2652 .owner = THIS_MODULE,
2653 .obj_size = sizeof(struct tun_file),
2654 };
2655
2656 static int tun_flags(struct tun_struct *tun)
2657 {
2658 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2659 }
2660
2661 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2662 char *buf)
2663 {
2664 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2665 return sprintf(buf, "0x%x\n", tun_flags(tun));
2666 }
2667
2668 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2669 char *buf)
2670 {
2671 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2672 return uid_valid(tun->owner)?
2673 sprintf(buf, "%u\n",
2674 from_kuid_munged(current_user_ns(), tun->owner)):
2675 sprintf(buf, "-1\n");
2676 }
2677
2678 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2679 char *buf)
2680 {
2681 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2682 return gid_valid(tun->group) ?
2683 sprintf(buf, "%u\n",
2684 from_kgid_munged(current_user_ns(), tun->group)):
2685 sprintf(buf, "-1\n");
2686 }
2687
2688 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2689 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2690 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2691
2692 static struct attribute *tun_dev_attrs[] = {
2693 &dev_attr_tun_flags.attr,
2694 &dev_attr_owner.attr,
2695 &dev_attr_group.attr,
2696 NULL
2697 };
2698
2699 static const struct attribute_group tun_attr_group = {
2700 .attrs = tun_dev_attrs
2701 };
2702
2703 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2704 {
2705 struct tun_struct *tun;
2706 struct tun_file *tfile = file->private_data;
2707 struct net_device *dev;
2708 int err;
2709
2710 if (tfile->detached)
2711 return -EINVAL;
2712
2713 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2714 if (!capable(CAP_NET_ADMIN))
2715 return -EPERM;
2716
2717 if (!(ifr->ifr_flags & IFF_NAPI) ||
2718 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2719 return -EINVAL;
2720 }
2721
2722 dev = __dev_get_by_name(net, ifr->ifr_name);
2723 if (dev) {
2724 if (ifr->ifr_flags & IFF_TUN_EXCL)
2725 return -EBUSY;
2726 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2727 tun = netdev_priv(dev);
2728 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2729 tun = netdev_priv(dev);
2730 else
2731 return -EINVAL;
2732
2733 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2734 !!(tun->flags & IFF_MULTI_QUEUE))
2735 return -EINVAL;
2736
2737 if (tun_not_capable(tun))
2738 return -EPERM;
2739 err = security_tun_dev_open(tun->security);
2740 if (err < 0)
2741 return err;
2742
2743 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2744 ifr->ifr_flags & IFF_NAPI,
2745 ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2746 if (err < 0)
2747 return err;
2748
2749 if (tun->flags & IFF_MULTI_QUEUE &&
2750 (tun->numqueues + tun->numdisabled > 1)) {
2751 /* One or more queue has already been attached, no need
2752 * to initialize the device again.
2753 */
2754 netdev_state_change(dev);
2755 return 0;
2756 }
2757
2758 tun->flags = (tun->flags & ~TUN_FEATURES) |
2759 (ifr->ifr_flags & TUN_FEATURES);
2760
2761 netdev_state_change(dev);
2762 } else {
2763 char *name;
2764 unsigned long flags = 0;
2765 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2766 MAX_TAP_QUEUES : 1;
2767
2768 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2769 return -EPERM;
2770 err = security_tun_dev_create();
2771 if (err < 0)
2772 return err;
2773
2774 /* Set dev type */
2775 if (ifr->ifr_flags & IFF_TUN) {
2776 /* TUN device */
2777 flags |= IFF_TUN;
2778 name = "tun%d";
2779 } else if (ifr->ifr_flags & IFF_TAP) {
2780 /* TAP device */
2781 flags |= IFF_TAP;
2782 name = "tap%d";
2783 } else
2784 return -EINVAL;
2785
2786 if (*ifr->ifr_name)
2787 name = ifr->ifr_name;
2788
2789 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2790 NET_NAME_UNKNOWN, tun_setup, queues,
2791 queues);
2792
2793 if (!dev)
2794 return -ENOMEM;
2795
2796 dev_net_set(dev, net);
2797 dev->rtnl_link_ops = &tun_link_ops;
2798 dev->ifindex = tfile->ifindex;
2799 dev->sysfs_groups[0] = &tun_attr_group;
2800
2801 tun = netdev_priv(dev);
2802 tun->dev = dev;
2803 tun->flags = flags;
2804 tun->txflt.count = 0;
2805 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2806
2807 tun->align = NET_SKB_PAD;
2808 tun->filter_attached = false;
2809 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2810 tun->rx_batched = 0;
2811 RCU_INIT_POINTER(tun->steering_prog, NULL);
2812
2813 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2814 if (!tun->pcpu_stats) {
2815 err = -ENOMEM;
2816 goto err_free_dev;
2817 }
2818
2819 spin_lock_init(&tun->lock);
2820
2821 err = security_tun_dev_alloc_security(&tun->security);
2822 if (err < 0)
2823 goto err_free_stat;
2824
2825 tun_net_init(dev);
2826 tun_flow_init(tun);
2827
2828 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2829 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2830 NETIF_F_HW_VLAN_STAG_TX;
2831 dev->features = dev->hw_features | NETIF_F_LLTX;
2832 dev->vlan_features = dev->features &
2833 ~(NETIF_F_HW_VLAN_CTAG_TX |
2834 NETIF_F_HW_VLAN_STAG_TX);
2835
2836 tun->flags = (tun->flags & ~TUN_FEATURES) |
2837 (ifr->ifr_flags & TUN_FEATURES);
2838
2839 INIT_LIST_HEAD(&tun->disabled);
2840 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI,
2841 ifr->ifr_flags & IFF_NAPI_FRAGS, false);
2842 if (err < 0)
2843 goto err_free_flow;
2844
2845 err = register_netdevice(tun->dev);
2846 if (err < 0)
2847 goto err_detach;
2848 /* free_netdev() won't check refcnt, to aovid race
2849 * with dev_put() we need publish tun after registration.
2850 */
2851 rcu_assign_pointer(tfile->tun, tun);
2852 }
2853
2854 netif_carrier_on(tun->dev);
2855
2856 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2857
2858 /* Make sure persistent devices do not get stuck in
2859 * xoff state.
2860 */
2861 if (netif_running(tun->dev))
2862 netif_tx_wake_all_queues(tun->dev);
2863
2864 strcpy(ifr->ifr_name, tun->dev->name);
2865 return 0;
2866
2867 err_detach:
2868 tun_detach_all(dev);
2869 /* We are here because register_netdevice() has failed.
2870 * If register_netdevice() already called tun_free_netdev()
2871 * while dealing with the error, tun->pcpu_stats has been cleared.
2872 */
2873 if (!tun->pcpu_stats)
2874 goto err_free_dev;
2875
2876 err_free_flow:
2877 tun_flow_uninit(tun);
2878 security_tun_dev_free_security(tun->security);
2879 err_free_stat:
2880 free_percpu(tun->pcpu_stats);
2881 err_free_dev:
2882 free_netdev(dev);
2883 return err;
2884 }
2885
2886 static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2887 {
2888 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2889
2890 strcpy(ifr->ifr_name, tun->dev->name);
2891
2892 ifr->ifr_flags = tun_flags(tun);
2893
2894 }
2895
2896 /* This is like a cut-down ethtool ops, except done via tun fd so no
2897 * privs required. */
2898 static int set_offload(struct tun_struct *tun, unsigned long arg)
2899 {
2900 netdev_features_t features = 0;
2901
2902 if (arg & TUN_F_CSUM) {
2903 features |= NETIF_F_HW_CSUM;
2904 arg &= ~TUN_F_CSUM;
2905
2906 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2907 if (arg & TUN_F_TSO_ECN) {
2908 features |= NETIF_F_TSO_ECN;
2909 arg &= ~TUN_F_TSO_ECN;
2910 }
2911 if (arg & TUN_F_TSO4)
2912 features |= NETIF_F_TSO;
2913 if (arg & TUN_F_TSO6)
2914 features |= NETIF_F_TSO6;
2915 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2916 }
2917
2918 arg &= ~TUN_F_UFO;
2919 }
2920
2921 /* This gives the user a way to test for new features in future by
2922 * trying to set them. */
2923 if (arg)
2924 return -EINVAL;
2925
2926 tun->set_features = features;
2927 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2928 tun->dev->wanted_features |= features;
2929 netdev_update_features(tun->dev);
2930
2931 return 0;
2932 }
2933
2934 static void tun_detach_filter(struct tun_struct *tun, int n)
2935 {
2936 int i;
2937 struct tun_file *tfile;
2938
2939 for (i = 0; i < n; i++) {
2940 tfile = rtnl_dereference(tun->tfiles[i]);
2941 lock_sock(tfile->socket.sk);
2942 sk_detach_filter(tfile->socket.sk);
2943 release_sock(tfile->socket.sk);
2944 }
2945
2946 tun->filter_attached = false;
2947 }
2948
2949 static int tun_attach_filter(struct tun_struct *tun)
2950 {
2951 int i, ret = 0;
2952 struct tun_file *tfile;
2953
2954 for (i = 0; i < tun->numqueues; i++) {
2955 tfile = rtnl_dereference(tun->tfiles[i]);
2956 lock_sock(tfile->socket.sk);
2957 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2958 release_sock(tfile->socket.sk);
2959 if (ret) {
2960 tun_detach_filter(tun, i);
2961 return ret;
2962 }
2963 }
2964
2965 tun->filter_attached = true;
2966 return ret;
2967 }
2968
2969 static void tun_set_sndbuf(struct tun_struct *tun)
2970 {
2971 struct tun_file *tfile;
2972 int i;
2973
2974 for (i = 0; i < tun->numqueues; i++) {
2975 tfile = rtnl_dereference(tun->tfiles[i]);
2976 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2977 }
2978 }
2979
2980 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2981 {
2982 struct tun_file *tfile = file->private_data;
2983 struct tun_struct *tun;
2984 int ret = 0;
2985
2986 rtnl_lock();
2987
2988 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2989 tun = tfile->detached;
2990 if (!tun) {
2991 ret = -EINVAL;
2992 goto unlock;
2993 }
2994 ret = security_tun_dev_attach_queue(tun->security);
2995 if (ret < 0)
2996 goto unlock;
2997 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2998 tun->flags & IFF_NAPI_FRAGS, true);
2999 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
3000 tun = rtnl_dereference(tfile->tun);
3001 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
3002 ret = -EINVAL;
3003 else
3004 __tun_detach(tfile, false);
3005 } else
3006 ret = -EINVAL;
3007
3008 if (ret >= 0)
3009 netdev_state_change(tun->dev);
3010
3011 unlock:
3012 rtnl_unlock();
3013 return ret;
3014 }
3015
3016 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
3017 void __user *data)
3018 {
3019 struct bpf_prog *prog;
3020 int fd;
3021
3022 if (copy_from_user(&fd, data, sizeof(fd)))
3023 return -EFAULT;
3024
3025 if (fd == -1) {
3026 prog = NULL;
3027 } else {
3028 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
3029 if (IS_ERR(prog))
3030 return PTR_ERR(prog);
3031 }
3032
3033 return __tun_set_ebpf(tun, prog_p, prog);
3034 }
3035
3036 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
3037 unsigned long arg, int ifreq_len)
3038 {
3039 struct tun_file *tfile = file->private_data;
3040 struct net *net = sock_net(&tfile->sk);
3041 struct tun_struct *tun;
3042 void __user* argp = (void __user*)arg;
3043 unsigned int ifindex, carrier;
3044 struct ifreq ifr;
3045 kuid_t owner;
3046 kgid_t group;
3047 int sndbuf;
3048 int vnet_hdr_sz;
3049 int le;
3050 int ret;
3051 bool do_notify = false;
3052
3053 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3054 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3055 if (copy_from_user(&ifr, argp, ifreq_len))
3056 return -EFAULT;
3057 } else {
3058 memset(&ifr, 0, sizeof(ifr));
3059 }
3060 if (cmd == TUNGETFEATURES) {
3061 /* Currently this just means: "what IFF flags are valid?".
3062 * This is needed because we never checked for invalid flags on
3063 * TUNSETIFF.
3064 */
3065 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
3066 (unsigned int __user*)argp);
3067 } else if (cmd == TUNSETQUEUE) {
3068 return tun_set_queue(file, &ifr);
3069 } else if (cmd == SIOCGSKNS) {
3070 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3071 return -EPERM;
3072 return open_related_ns(&net->ns, get_net_ns);
3073 }
3074
3075 ret = 0;
3076 rtnl_lock();
3077
3078 tun = tun_get(tfile);
3079 if (cmd == TUNSETIFF) {
3080 ret = -EEXIST;
3081 if (tun)
3082 goto unlock;
3083
3084 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3085
3086 ret = tun_set_iff(net, file, &ifr);
3087
3088 if (ret)
3089 goto unlock;
3090
3091 if (copy_to_user(argp, &ifr, ifreq_len))
3092 ret = -EFAULT;
3093 goto unlock;
3094 }
3095 if (cmd == TUNSETIFINDEX) {
3096 ret = -EPERM;
3097 if (tun)
3098 goto unlock;
3099
3100 ret = -EFAULT;
3101 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3102 goto unlock;
3103
3104 ret = 0;
3105 tfile->ifindex = ifindex;
3106 goto unlock;
3107 }
3108
3109 ret = -EBADFD;
3110 if (!tun)
3111 goto unlock;
3112
3113 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
3114
3115 net = dev_net(tun->dev);
3116 ret = 0;
3117 switch (cmd) {
3118 case TUNGETIFF:
3119 tun_get_iff(tun, &ifr);
3120
3121 if (tfile->detached)
3122 ifr.ifr_flags |= IFF_DETACH_QUEUE;
3123 if (!tfile->socket.sk->sk_filter)
3124 ifr.ifr_flags |= IFF_NOFILTER;
3125
3126 if (copy_to_user(argp, &ifr, ifreq_len))
3127 ret = -EFAULT;
3128 break;
3129
3130 case TUNSETNOCSUM:
3131 /* Disable/Enable checksum */
3132
3133 /* [unimplemented] */
3134 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
3135 arg ? "disabled" : "enabled");
3136 break;
3137
3138 case TUNSETPERSIST:
3139 /* Disable/Enable persist mode. Keep an extra reference to the
3140 * module to prevent the module being unprobed.
3141 */
3142 if (arg && !(tun->flags & IFF_PERSIST)) {
3143 tun->flags |= IFF_PERSIST;
3144 __module_get(THIS_MODULE);
3145 do_notify = true;
3146 }
3147 if (!arg && (tun->flags & IFF_PERSIST)) {
3148 tun->flags &= ~IFF_PERSIST;
3149 module_put(THIS_MODULE);
3150 do_notify = true;
3151 }
3152
3153 tun_debug(KERN_INFO, tun, "persist %s\n",
3154 arg ? "enabled" : "disabled");
3155 break;
3156
3157 case TUNSETOWNER:
3158 /* Set owner of the device */
3159 owner = make_kuid(current_user_ns(), arg);
3160 if (!uid_valid(owner)) {
3161 ret = -EINVAL;
3162 break;
3163 }
3164 tun->owner = owner;
3165 do_notify = true;
3166 tun_debug(KERN_INFO, tun, "owner set to %u\n",
3167 from_kuid(&init_user_ns, tun->owner));
3168 break;
3169
3170 case TUNSETGROUP:
3171 /* Set group of the device */
3172 group = make_kgid(current_user_ns(), arg);
3173 if (!gid_valid(group)) {
3174 ret = -EINVAL;
3175 break;
3176 }
3177 tun->group = group;
3178 do_notify = true;
3179 tun_debug(KERN_INFO, tun, "group set to %u\n",
3180 from_kgid(&init_user_ns, tun->group));
3181 break;
3182
3183 case TUNSETLINK:
3184 /* Only allow setting the type when the interface is down */
3185 if (tun->dev->flags & IFF_UP) {
3186 tun_debug(KERN_INFO, tun,
3187 "Linktype set failed because interface is up\n");
3188 ret = -EBUSY;
3189 } else {
3190 tun->dev->type = (int) arg;
3191 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
3192 tun->dev->type);
3193 ret = 0;
3194 }
3195 break;
3196
3197 #ifdef TUN_DEBUG
3198 case TUNSETDEBUG:
3199 tun->debug = arg;
3200 break;
3201 #endif
3202 case TUNSETOFFLOAD:
3203 ret = set_offload(tun, arg);
3204 break;
3205
3206 case TUNSETTXFILTER:
3207 /* Can be set only for TAPs */
3208 ret = -EINVAL;
3209 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3210 break;
3211 ret = update_filter(&tun->txflt, (void __user *)arg);
3212 break;
3213
3214 case SIOCGIFHWADDR:
3215 /* Get hw address */
3216 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3217 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3218 if (copy_to_user(argp, &ifr, ifreq_len))
3219 ret = -EFAULT;
3220 break;
3221
3222 case SIOCSIFHWADDR:
3223 /* Set hw address */
3224 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
3225 ifr.ifr_hwaddr.sa_data);
3226
3227 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr, NULL);
3228 break;
3229
3230 case TUNGETSNDBUF:
3231 sndbuf = tfile->socket.sk->sk_sndbuf;
3232 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3233 ret = -EFAULT;
3234 break;
3235
3236 case TUNSETSNDBUF:
3237 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3238 ret = -EFAULT;
3239 break;
3240 }
3241 if (sndbuf <= 0) {
3242 ret = -EINVAL;
3243 break;
3244 }
3245
3246 tun->sndbuf = sndbuf;
3247 tun_set_sndbuf(tun);
3248 break;
3249
3250 case TUNGETVNETHDRSZ:
3251 vnet_hdr_sz = tun->vnet_hdr_sz;
3252 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3253 ret = -EFAULT;
3254 break;
3255
3256 case TUNSETVNETHDRSZ:
3257 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3258 ret = -EFAULT;
3259 break;
3260 }
3261 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3262 ret = -EINVAL;
3263 break;
3264 }
3265
3266 tun->vnet_hdr_sz = vnet_hdr_sz;
3267 break;
3268
3269 case TUNGETVNETLE:
3270 le = !!(tun->flags & TUN_VNET_LE);
3271 if (put_user(le, (int __user *)argp))
3272 ret = -EFAULT;
3273 break;
3274
3275 case TUNSETVNETLE:
3276 if (get_user(le, (int __user *)argp)) {
3277 ret = -EFAULT;
3278 break;
3279 }
3280 if (le)
3281 tun->flags |= TUN_VNET_LE;
3282 else
3283 tun->flags &= ~TUN_VNET_LE;
3284 break;
3285
3286 case TUNGETVNETBE:
3287 ret = tun_get_vnet_be(tun, argp);
3288 break;
3289
3290 case TUNSETVNETBE:
3291 ret = tun_set_vnet_be(tun, argp);
3292 break;
3293
3294 case TUNATTACHFILTER:
3295 /* Can be set only for TAPs */
3296 ret = -EINVAL;
3297 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3298 break;
3299 ret = -EFAULT;
3300 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3301 break;
3302
3303 ret = tun_attach_filter(tun);
3304 break;
3305
3306 case TUNDETACHFILTER:
3307 /* Can be set only for TAPs */
3308 ret = -EINVAL;
3309 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3310 break;
3311 ret = 0;
3312 tun_detach_filter(tun, tun->numqueues);
3313 break;
3314
3315 case TUNGETFILTER:
3316 ret = -EINVAL;
3317 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3318 break;
3319 ret = -EFAULT;
3320 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3321 break;
3322 ret = 0;
3323 break;
3324
3325 case TUNSETSTEERINGEBPF:
3326 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3327 break;
3328
3329 case TUNSETFILTEREBPF:
3330 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3331 break;
3332
3333 case TUNSETCARRIER:
3334 ret = -EFAULT;
3335 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3336 goto unlock;
3337
3338 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3339 break;
3340
3341 case TUNGETDEVNETNS:
3342 ret = -EPERM;
3343 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3344 goto unlock;
3345 ret = open_related_ns(&net->ns, get_net_ns);
3346 break;
3347
3348 default:
3349 ret = -EINVAL;
3350 break;
3351 }
3352
3353 if (do_notify)
3354 netdev_state_change(tun->dev);
3355
3356 unlock:
3357 rtnl_unlock();
3358 if (tun)
3359 tun_put(tun);
3360 return ret;
3361 }
3362
3363 static long tun_chr_ioctl(struct file *file,
3364 unsigned int cmd, unsigned long arg)
3365 {
3366 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3367 }
3368
3369 #ifdef CONFIG_COMPAT
3370 static long tun_chr_compat_ioctl(struct file *file,
3371 unsigned int cmd, unsigned long arg)
3372 {
3373 switch (cmd) {
3374 case TUNSETIFF:
3375 case TUNGETIFF:
3376 case TUNSETTXFILTER:
3377 case TUNGETSNDBUF:
3378 case TUNSETSNDBUF:
3379 case SIOCGIFHWADDR:
3380 case SIOCSIFHWADDR:
3381 arg = (unsigned long)compat_ptr(arg);
3382 break;
3383 default:
3384 arg = (compat_ulong_t)arg;
3385 break;
3386 }
3387
3388 /*
3389 * compat_ifreq is shorter than ifreq, so we must not access beyond
3390 * the end of that structure. All fields that are used in this
3391 * driver are compatible though, we don't need to convert the
3392 * contents.
3393 */
3394 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3395 }
3396 #endif /* CONFIG_COMPAT */
3397
3398 static int tun_chr_fasync(int fd, struct file *file, int on)
3399 {
3400 struct tun_file *tfile = file->private_data;
3401 int ret;
3402
3403 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3404 goto out;
3405
3406 if (on) {
3407 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3408 tfile->flags |= TUN_FASYNC;
3409 } else
3410 tfile->flags &= ~TUN_FASYNC;
3411 ret = 0;
3412 out:
3413 return ret;
3414 }
3415
3416 static int tun_chr_open(struct inode *inode, struct file * file)
3417 {
3418 struct net *net = current->nsproxy->net_ns;
3419 struct tun_file *tfile;
3420
3421 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
3422
3423 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3424 &tun_proto, 0);
3425 if (!tfile)
3426 return -ENOMEM;
3427 if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3428 sk_free(&tfile->sk);
3429 return -ENOMEM;
3430 }
3431
3432 mutex_init(&tfile->napi_mutex);
3433 RCU_INIT_POINTER(tfile->tun, NULL);
3434 tfile->flags = 0;
3435 tfile->ifindex = 0;
3436
3437 init_waitqueue_head(&tfile->socket.wq.wait);
3438
3439 tfile->socket.file = file;
3440 tfile->socket.ops = &tun_socket_ops;
3441
3442 sock_init_data(&tfile->socket, &tfile->sk);
3443
3444 tfile->sk.sk_write_space = tun_sock_write_space;
3445 tfile->sk.sk_sndbuf = INT_MAX;
3446
3447 file->private_data = tfile;
3448 INIT_LIST_HEAD(&tfile->next);
3449
3450 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3451
3452 return 0;
3453 }
3454
3455 static int tun_chr_close(struct inode *inode, struct file *file)
3456 {
3457 struct tun_file *tfile = file->private_data;
3458
3459 tun_detach(tfile, true);
3460
3461 return 0;
3462 }
3463
3464 #ifdef CONFIG_PROC_FS
3465 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3466 {
3467 struct tun_file *tfile = file->private_data;
3468 struct tun_struct *tun;
3469 struct ifreq ifr;
3470
3471 memset(&ifr, 0, sizeof(ifr));
3472
3473 rtnl_lock();
3474 tun = tun_get(tfile);
3475 if (tun)
3476 tun_get_iff(tun, &ifr);
3477 rtnl_unlock();
3478
3479 if (tun)
3480 tun_put(tun);
3481
3482 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3483 }
3484 #endif
3485
3486 static const struct file_operations tun_fops = {
3487 .owner = THIS_MODULE,
3488 .llseek = no_llseek,
3489 .read_iter = tun_chr_read_iter,
3490 .write_iter = tun_chr_write_iter,
3491 .poll = tun_chr_poll,
3492 .unlocked_ioctl = tun_chr_ioctl,
3493 #ifdef CONFIG_COMPAT
3494 .compat_ioctl = tun_chr_compat_ioctl,
3495 #endif
3496 .open = tun_chr_open,
3497 .release = tun_chr_close,
3498 .fasync = tun_chr_fasync,
3499 #ifdef CONFIG_PROC_FS
3500 .show_fdinfo = tun_chr_show_fdinfo,
3501 #endif
3502 };
3503
3504 static struct miscdevice tun_miscdev = {
3505 .minor = TUN_MINOR,
3506 .name = "tun",
3507 .nodename = "net/tun",
3508 .fops = &tun_fops,
3509 };
3510
3511 /* ethtool interface */
3512
3513 static void tun_default_link_ksettings(struct net_device *dev,
3514 struct ethtool_link_ksettings *cmd)
3515 {
3516 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3517 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3518 cmd->base.speed = SPEED_10;
3519 cmd->base.duplex = DUPLEX_FULL;
3520 cmd->base.port = PORT_TP;
3521 cmd->base.phy_address = 0;
3522 cmd->base.autoneg = AUTONEG_DISABLE;
3523 }
3524
3525 static int tun_get_link_ksettings(struct net_device *dev,
3526 struct ethtool_link_ksettings *cmd)
3527 {
3528 struct tun_struct *tun = netdev_priv(dev);
3529
3530 memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3531 return 0;
3532 }
3533
3534 static int tun_set_link_ksettings(struct net_device *dev,
3535 const struct ethtool_link_ksettings *cmd)
3536 {
3537 struct tun_struct *tun = netdev_priv(dev);
3538
3539 memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3540 return 0;
3541 }
3542
3543 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3544 {
3545 struct tun_struct *tun = netdev_priv(dev);
3546
3547 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3548 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3549
3550 switch (tun->flags & TUN_TYPE_MASK) {
3551 case IFF_TUN:
3552 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3553 break;
3554 case IFF_TAP:
3555 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3556 break;
3557 }
3558 }
3559
3560 static u32 tun_get_msglevel(struct net_device *dev)
3561 {
3562 #ifdef TUN_DEBUG
3563 struct tun_struct *tun = netdev_priv(dev);
3564 return tun->debug;
3565 #else
3566 return -EOPNOTSUPP;
3567 #endif
3568 }
3569
3570 static void tun_set_msglevel(struct net_device *dev, u32 value)
3571 {
3572 #ifdef TUN_DEBUG
3573 struct tun_struct *tun = netdev_priv(dev);
3574 tun->debug = value;
3575 #endif
3576 }
3577
3578 static int tun_get_coalesce(struct net_device *dev,
3579 struct ethtool_coalesce *ec)
3580 {
3581 struct tun_struct *tun = netdev_priv(dev);
3582
3583 ec->rx_max_coalesced_frames = tun->rx_batched;
3584
3585 return 0;
3586 }
3587
3588 static int tun_set_coalesce(struct net_device *dev,
3589 struct ethtool_coalesce *ec)
3590 {
3591 struct tun_struct *tun = netdev_priv(dev);
3592
3593 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3594 tun->rx_batched = NAPI_POLL_WEIGHT;
3595 else
3596 tun->rx_batched = ec->rx_max_coalesced_frames;
3597
3598 return 0;
3599 }
3600
3601 static const struct ethtool_ops tun_ethtool_ops = {
3602 .get_drvinfo = tun_get_drvinfo,
3603 .get_msglevel = tun_get_msglevel,
3604 .set_msglevel = tun_set_msglevel,
3605 .get_link = ethtool_op_get_link,
3606 .get_ts_info = ethtool_op_get_ts_info,
3607 .get_coalesce = tun_get_coalesce,
3608 .set_coalesce = tun_set_coalesce,
3609 .get_link_ksettings = tun_get_link_ksettings,
3610 .set_link_ksettings = tun_set_link_ksettings,
3611 };
3612
3613 static int tun_queue_resize(struct tun_struct *tun)
3614 {
3615 struct net_device *dev = tun->dev;
3616 struct tun_file *tfile;
3617 struct ptr_ring **rings;
3618 int n = tun->numqueues + tun->numdisabled;
3619 int ret, i;
3620
3621 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3622 if (!rings)
3623 return -ENOMEM;
3624
3625 for (i = 0; i < tun->numqueues; i++) {
3626 tfile = rtnl_dereference(tun->tfiles[i]);
3627 rings[i] = &tfile->tx_ring;
3628 }
3629 list_for_each_entry(tfile, &tun->disabled, next)
3630 rings[i++] = &tfile->tx_ring;
3631
3632 ret = ptr_ring_resize_multiple(rings, n,
3633 dev->tx_queue_len, GFP_KERNEL,
3634 tun_ptr_free);
3635
3636 kfree(rings);
3637 return ret;
3638 }
3639
3640 static int tun_device_event(struct notifier_block *unused,
3641 unsigned long event, void *ptr)
3642 {
3643 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3644 struct tun_struct *tun = netdev_priv(dev);
3645 int i;
3646
3647 if (dev->rtnl_link_ops != &tun_link_ops)
3648 return NOTIFY_DONE;
3649
3650 switch (event) {
3651 case NETDEV_CHANGE_TX_QUEUE_LEN:
3652 if (tun_queue_resize(tun))
3653 return NOTIFY_BAD;
3654 break;
3655 case NETDEV_UP:
3656 for (i = 0; i < tun->numqueues; i++) {
3657 struct tun_file *tfile;
3658
3659 tfile = rtnl_dereference(tun->tfiles[i]);
3660 tfile->socket.sk->sk_write_space(tfile->socket.sk);
3661 }
3662 break;
3663 default:
3664 break;
3665 }
3666
3667 return NOTIFY_DONE;
3668 }
3669
3670 static struct notifier_block tun_notifier_block __read_mostly = {
3671 .notifier_call = tun_device_event,
3672 };
3673
3674 static int __init tun_init(void)
3675 {
3676 int ret = 0;
3677
3678 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3679
3680 ret = rtnl_link_register(&tun_link_ops);
3681 if (ret) {
3682 pr_err("Can't register link_ops\n");
3683 goto err_linkops;
3684 }
3685
3686 ret = misc_register(&tun_miscdev);
3687 if (ret) {
3688 pr_err("Can't register misc device %d\n", TUN_MINOR);
3689 goto err_misc;
3690 }
3691
3692 ret = register_netdevice_notifier(&tun_notifier_block);
3693 if (ret) {
3694 pr_err("Can't register netdevice notifier\n");
3695 goto err_notifier;
3696 }
3697
3698 return 0;
3699
3700 err_notifier:
3701 misc_deregister(&tun_miscdev);
3702 err_misc:
3703 rtnl_link_unregister(&tun_link_ops);
3704 err_linkops:
3705 return ret;
3706 }
3707
3708 static void tun_cleanup(void)
3709 {
3710 misc_deregister(&tun_miscdev);
3711 rtnl_link_unregister(&tun_link_ops);
3712 unregister_netdevice_notifier(&tun_notifier_block);
3713 }
3714
3715 /* Get an underlying socket object from tun file. Returns error unless file is
3716 * attached to a device. The returned object works like a packet socket, it
3717 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3718 * holding a reference to the file for as long as the socket is in use. */
3719 struct socket *tun_get_socket(struct file *file)
3720 {
3721 struct tun_file *tfile;
3722 if (file->f_op != &tun_fops)
3723 return ERR_PTR(-EINVAL);
3724 tfile = file->private_data;
3725 if (!tfile)
3726 return ERR_PTR(-EBADFD);
3727 return &tfile->socket;
3728 }
3729 EXPORT_SYMBOL_GPL(tun_get_socket);
3730
3731 struct ptr_ring *tun_get_tx_ring(struct file *file)
3732 {
3733 struct tun_file *tfile;
3734
3735 if (file->f_op != &tun_fops)
3736 return ERR_PTR(-EINVAL);
3737 tfile = file->private_data;
3738 if (!tfile)
3739 return ERR_PTR(-EBADFD);
3740 return &tfile->tx_ring;
3741 }
3742 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3743
3744 module_init(tun_init);
3745 module_exit(tun_cleanup);
3746 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3747 MODULE_AUTHOR(DRV_COPYRIGHT);
3748 MODULE_LICENSE("GPL");
3749 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3750 MODULE_ALIAS("devname:net/tun");
Linux with added FPC-III support