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