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