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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * TUN - Universal TUN/TAP device driver.
4 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
5 *
6 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
7 */
8
9/*
10 * Changes:
11 *
12 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
13 * Add TUNSETLINK ioctl to set the link encapsulation
14 *
15 * Mark Smith <markzzzsmith@yahoo.com.au>
16 * Use eth_random_addr() for tap MAC address.
17 *
18 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
19 * Fixes in packet dropping, queue length setting and queue wakeup.
20 * Increased default tx queue length.
21 * Added ethtool API.
22 * Minor cleanups
23 *
24 * Daniel Podlejski <underley@underley.eu.org>
25 * Modifications for 2.3.99-pre5 kernel.
26 */
27
28#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29
30#define DRV_NAME "tun"
31#define DRV_VERSION "1.6"
32#define DRV_DESCRIPTION "Universal TUN/TAP device driver"
33#define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
34
35#include <linux/module.h>
36#include <linux/errno.h>
37#include <linux/kernel.h>
38#include <linux/sched/signal.h>
39#include <linux/major.h>
40#include <linux/slab.h>
41#include <linux/poll.h>
42#include <linux/fcntl.h>
43#include <linux/init.h>
44#include <linux/skbuff.h>
45#include <linux/netdevice.h>
46#include <linux/etherdevice.h>
47#include <linux/miscdevice.h>
48#include <linux/ethtool.h>
49#include <linux/rtnetlink.h>
50#include <linux/compat.h>
51#include <linux/if.h>
52#include <linux/if_arp.h>
53#include <linux/if_ether.h>
54#include <linux/if_tun.h>
55#include <linux/if_vlan.h>
56#include <linux/crc32.h>
57#include <linux/nsproxy.h>
58#include <linux/virtio_net.h>
59#include <linux/rcupdate.h>
60#include <net/net_namespace.h>
61#include <net/netns/generic.h>
62#include <net/rtnetlink.h>
63#include <net/sock.h>
64#include <net/xdp.h>
65#include <net/ip_tunnels.h>
66#include <linux/seq_file.h>
67#include <linux/uio.h>
68#include <linux/skb_array.h>
69#include <linux/bpf.h>
70#include <linux/bpf_trace.h>
71#include <linux/mutex.h>
72#include <linux/ieee802154.h>
73#include <linux/if_ltalk.h>
74#include <uapi/linux/if_fddi.h>
75#include <uapi/linux/if_hippi.h>
76#include <uapi/linux/if_fc.h>
77#include <net/ax25.h>
78#include <net/rose.h>
79#include <net/6lowpan.h>
80
81#include <linux/uaccess.h>
82#include <linux/proc_fs.h>
83
84static void tun_default_link_ksettings(struct net_device *dev,
85 struct ethtool_link_ksettings *cmd);
86
87#define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
88
89/* TUN device flags */
90
91/* IFF_ATTACH_QUEUE is never stored in device flags,
92 * overload it to mean fasync when stored there.
93 */
94#define TUN_FASYNC IFF_ATTACH_QUEUE
95/* High bits in flags field are unused. */
96#define TUN_VNET_LE 0x80000000
97#define TUN_VNET_BE 0x40000000
98
99#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
100 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
101
102#define GOODCOPY_LEN 128
103
104#define FLT_EXACT_COUNT 8
105struct tap_filter {
106 unsigned int count; /* Number of addrs. Zero means disabled */
107 u32 mask[2]; /* Mask of the hashed addrs */
108 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
109};
110
111/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
112 * to max number of VCPUs in guest. */
113#define MAX_TAP_QUEUES 256
114#define MAX_TAP_FLOWS 4096
115
116#define TUN_FLOW_EXPIRE (3 * HZ)
117
118/* A tun_file connects an open character device to a tuntap netdevice. It
119 * also contains all socket related structures (except sock_fprog and tap_filter)
120 * to serve as one transmit queue for tuntap device. The sock_fprog and
121 * tap_filter were kept in tun_struct since they were used for filtering for the
122 * netdevice not for a specific queue (at least I didn't see the requirement for
123 * this).
124 *
125 * RCU usage:
126 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
127 * other can only be read while rcu_read_lock or rtnl_lock is held.
128 */
129struct tun_file {
130 struct sock sk;
131 struct socket socket;
132 struct tun_struct __rcu *tun;
133 struct fasync_struct *fasync;
134 /* only used for fasnyc */
135 unsigned int flags;
136 union {
137 u16 queue_index;
138 unsigned int ifindex;
139 };
140 struct napi_struct napi;
141 bool napi_enabled;
142 bool napi_frags_enabled;
143 struct mutex napi_mutex; /* Protects access to the above napi */
144 struct list_head next;
145 struct tun_struct *detached;
146 struct ptr_ring tx_ring;
147 struct xdp_rxq_info xdp_rxq;
148};
149
150struct tun_page {
151 struct page *page;
152 int count;
153};
154
155struct tun_flow_entry {
156 struct hlist_node hash_link;
157 struct rcu_head rcu;
158 struct tun_struct *tun;
159
160 u32 rxhash;
161 u32 rps_rxhash;
162 int queue_index;
163 unsigned long updated ____cacheline_aligned_in_smp;
164};
165
166#define TUN_NUM_FLOW_ENTRIES 1024
167#define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
168
169struct tun_prog {
170 struct rcu_head rcu;
171 struct bpf_prog *prog;
172};
173
174/* Since the socket were moved to tun_file, to preserve the behavior of persist
175 * device, socket filter, sndbuf and vnet header size were restore when the
176 * file were attached to a persist device.
177 */
178struct tun_struct {
179 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
180 unsigned int numqueues;
181 unsigned int flags;
182 kuid_t owner;
183 kgid_t group;
184
185 struct net_device *dev;
186 netdev_features_t set_features;
187#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
188 NETIF_F_TSO6)
189
190 int align;
191 int vnet_hdr_sz;
192 int sndbuf;
193 struct tap_filter txflt;
194 struct sock_fprog fprog;
195 /* protected by rtnl lock */
196 bool filter_attached;
197 u32 msg_enable;
198 spinlock_t lock;
199 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
200 struct timer_list flow_gc_timer;
201 unsigned long ageing_time;
202 unsigned int numdisabled;
203 struct list_head disabled;
204 void *security;
205 u32 flow_count;
206 u32 rx_batched;
207 atomic_long_t rx_frame_errors;
208 struct bpf_prog __rcu *xdp_prog;
209 struct tun_prog __rcu *steering_prog;
210 struct tun_prog __rcu *filter_prog;
211 struct ethtool_link_ksettings link_ksettings;
212};
213
214struct veth {
215 __be16 h_vlan_proto;
216 __be16 h_vlan_TCI;
217};
218
219static int tun_napi_receive(struct napi_struct *napi, int budget)
220{
221 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
222 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
223 struct sk_buff_head process_queue;
224 struct sk_buff *skb;
225 int received = 0;
226
227 __skb_queue_head_init(&process_queue);
228
229 spin_lock(&queue->lock);
230 skb_queue_splice_tail_init(queue, &process_queue);
231 spin_unlock(&queue->lock);
232
233 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
234 napi_gro_receive(napi, skb);
235 ++received;
236 }
237
238 if (!skb_queue_empty(&process_queue)) {
239 spin_lock(&queue->lock);
240 skb_queue_splice(&process_queue, queue);
241 spin_unlock(&queue->lock);
242 }
243
244 return received;
245}
246
247static int tun_napi_poll(struct napi_struct *napi, int budget)
248{
249 unsigned int received;
250
251 received = tun_napi_receive(napi, budget);
252
253 if (received < budget)
254 napi_complete_done(napi, received);
255
256 return received;
257}
258
259static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
260 bool napi_en, bool napi_frags)
261{
262 tfile->napi_enabled = napi_en;
263 tfile->napi_frags_enabled = napi_en && napi_frags;
264 if (napi_en) {
265 netif_tx_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
266 NAPI_POLL_WEIGHT);
267 napi_enable(&tfile->napi);
268 }
269}
270
271static void tun_napi_disable(struct tun_file *tfile)
272{
273 if (tfile->napi_enabled)
274 napi_disable(&tfile->napi);
275}
276
277static void tun_napi_del(struct tun_file *tfile)
278{
279 if (tfile->napi_enabled)
280 netif_napi_del(&tfile->napi);
281}
282
283static bool tun_napi_frags_enabled(const struct tun_file *tfile)
284{
285 return tfile->napi_frags_enabled;
286}
287
288#ifdef CONFIG_TUN_VNET_CROSS_LE
289static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
290{
291 return tun->flags & TUN_VNET_BE ? false :
292 virtio_legacy_is_little_endian();
293}
294
295static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
296{
297 int be = !!(tun->flags & TUN_VNET_BE);
298
299 if (put_user(be, argp))
300 return -EFAULT;
301
302 return 0;
303}
304
305static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
306{
307 int be;
308
309 if (get_user(be, argp))
310 return -EFAULT;
311
312 if (be)
313 tun->flags |= TUN_VNET_BE;
314 else
315 tun->flags &= ~TUN_VNET_BE;
316
317 return 0;
318}
319#else
320static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
321{
322 return virtio_legacy_is_little_endian();
323}
324
325static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
326{
327 return -EINVAL;
328}
329
330static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
331{
332 return -EINVAL;
333}
334#endif /* CONFIG_TUN_VNET_CROSS_LE */
335
336static inline bool tun_is_little_endian(struct tun_struct *tun)
337{
338 return tun->flags & TUN_VNET_LE ||
339 tun_legacy_is_little_endian(tun);
340}
341
342static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
343{
344 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
345}
346
347static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
348{
349 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
350}
351
352static inline u32 tun_hashfn(u32 rxhash)
353{
354 return rxhash & TUN_MASK_FLOW_ENTRIES;
355}
356
357static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
358{
359 struct tun_flow_entry *e;
360
361 hlist_for_each_entry_rcu(e, head, hash_link) {
362 if (e->rxhash == rxhash)
363 return e;
364 }
365 return NULL;
366}
367
368static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
369 struct hlist_head *head,
370 u32 rxhash, u16 queue_index)
371{
372 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
373
374 if (e) {
375 netif_info(tun, tx_queued, tun->dev,
376 "create flow: hash %u index %u\n",
377 rxhash, queue_index);
378 e->updated = jiffies;
379 e->rxhash = rxhash;
380 e->rps_rxhash = 0;
381 e->queue_index = queue_index;
382 e->tun = tun;
383 hlist_add_head_rcu(&e->hash_link, head);
384 ++tun->flow_count;
385 }
386 return e;
387}
388
389static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
390{
391 netif_info(tun, tx_queued, tun->dev, "delete flow: hash %u index %u\n",
392 e->rxhash, e->queue_index);
393 hlist_del_rcu(&e->hash_link);
394 kfree_rcu(e, rcu);
395 --tun->flow_count;
396}
397
398static void tun_flow_flush(struct tun_struct *tun)
399{
400 int i;
401
402 spin_lock_bh(&tun->lock);
403 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
404 struct tun_flow_entry *e;
405 struct hlist_node *n;
406
407 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
408 tun_flow_delete(tun, e);
409 }
410 spin_unlock_bh(&tun->lock);
411}
412
413static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
414{
415 int i;
416
417 spin_lock_bh(&tun->lock);
418 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
419 struct tun_flow_entry *e;
420 struct hlist_node *n;
421
422 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
423 if (e->queue_index == queue_index)
424 tun_flow_delete(tun, e);
425 }
426 }
427 spin_unlock_bh(&tun->lock);
428}
429
430static void tun_flow_cleanup(struct timer_list *t)
431{
432 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
433 unsigned long delay = tun->ageing_time;
434 unsigned long next_timer = jiffies + delay;
435 unsigned long count = 0;
436 int i;
437
438 spin_lock(&tun->lock);
439 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
440 struct tun_flow_entry *e;
441 struct hlist_node *n;
442
443 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
444 unsigned long this_timer;
445
446 this_timer = e->updated + delay;
447 if (time_before_eq(this_timer, jiffies)) {
448 tun_flow_delete(tun, e);
449 continue;
450 }
451 count++;
452 if (time_before(this_timer, next_timer))
453 next_timer = this_timer;
454 }
455 }
456
457 if (count)
458 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
459 spin_unlock(&tun->lock);
460}
461
462static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
463 struct tun_file *tfile)
464{
465 struct hlist_head *head;
466 struct tun_flow_entry *e;
467 unsigned long delay = tun->ageing_time;
468 u16 queue_index = tfile->queue_index;
469
470 head = &tun->flows[tun_hashfn(rxhash)];
471
472 rcu_read_lock();
473
474 e = tun_flow_find(head, rxhash);
475 if (likely(e)) {
476 /* TODO: keep queueing to old queue until it's empty? */
477 if (READ_ONCE(e->queue_index) != queue_index)
478 WRITE_ONCE(e->queue_index, queue_index);
479 if (e->updated != jiffies)
480 e->updated = jiffies;
481 sock_rps_record_flow_hash(e->rps_rxhash);
482 } else {
483 spin_lock_bh(&tun->lock);
484 if (!tun_flow_find(head, rxhash) &&
485 tun->flow_count < MAX_TAP_FLOWS)
486 tun_flow_create(tun, head, rxhash, queue_index);
487
488 if (!timer_pending(&tun->flow_gc_timer))
489 mod_timer(&tun->flow_gc_timer,
490 round_jiffies_up(jiffies + delay));
491 spin_unlock_bh(&tun->lock);
492 }
493
494 rcu_read_unlock();
495}
496
497/* Save the hash received in the stack receive path and update the
498 * flow_hash table accordingly.
499 */
500static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
501{
502 if (unlikely(e->rps_rxhash != hash))
503 e->rps_rxhash = hash;
504}
505
506/* We try to identify a flow through its rxhash. The reason that
507 * we do not check rxq no. is because some cards(e.g 82599), chooses
508 * the rxq based on the txq where the last packet of the flow comes. As
509 * the userspace application move between processors, we may get a
510 * different rxq no. here.
511 */
512static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
513{
514 struct tun_flow_entry *e;
515 u32 txq = 0;
516 u32 numqueues = 0;
517
518 numqueues = READ_ONCE(tun->numqueues);
519
520 txq = __skb_get_hash_symmetric(skb);
521 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
522 if (e) {
523 tun_flow_save_rps_rxhash(e, txq);
524 txq = e->queue_index;
525 } else {
526 /* use multiply and shift instead of expensive divide */
527 txq = ((u64)txq * numqueues) >> 32;
528 }
529
530 return txq;
531}
532
533static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
534{
535 struct tun_prog *prog;
536 u32 numqueues;
537 u16 ret = 0;
538
539 numqueues = READ_ONCE(tun->numqueues);
540 if (!numqueues)
541 return 0;
542
543 prog = rcu_dereference(tun->steering_prog);
544 if (prog)
545 ret = bpf_prog_run_clear_cb(prog->prog, skb);
546
547 return ret % numqueues;
548}
549
550static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
551 struct net_device *sb_dev)
552{
553 struct tun_struct *tun = netdev_priv(dev);
554 u16 ret;
555
556 rcu_read_lock();
557 if (rcu_dereference(tun->steering_prog))
558 ret = tun_ebpf_select_queue(tun, skb);
559 else
560 ret = tun_automq_select_queue(tun, skb);
561 rcu_read_unlock();
562
563 return ret;
564}
565
566static inline bool tun_not_capable(struct tun_struct *tun)
567{
568 const struct cred *cred = current_cred();
569 struct net *net = dev_net(tun->dev);
570
571 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
572 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
573 !ns_capable(net->user_ns, CAP_NET_ADMIN);
574}
575
576static void tun_set_real_num_queues(struct tun_struct *tun)
577{
578 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
579 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
580}
581
582static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
583{
584 tfile->detached = tun;
585 list_add_tail(&tfile->next, &tun->disabled);
586 ++tun->numdisabled;
587}
588
589static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
590{
591 struct tun_struct *tun = tfile->detached;
592
593 tfile->detached = NULL;
594 list_del_init(&tfile->next);
595 --tun->numdisabled;
596 return tun;
597}
598
599void tun_ptr_free(void *ptr)
600{
601 if (!ptr)
602 return;
603 if (tun_is_xdp_frame(ptr)) {
604 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
605
606 xdp_return_frame(xdpf);
607 } else {
608 __skb_array_destroy_skb(ptr);
609 }
610}
611EXPORT_SYMBOL_GPL(tun_ptr_free);
612
613static void tun_queue_purge(struct tun_file *tfile)
614{
615 void *ptr;
616
617 while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
618 tun_ptr_free(ptr);
619
620 skb_queue_purge(&tfile->sk.sk_write_queue);
621 skb_queue_purge(&tfile->sk.sk_error_queue);
622}
623
624static void __tun_detach(struct tun_file *tfile, bool clean)
625{
626 struct tun_file *ntfile;
627 struct tun_struct *tun;
628
629 tun = rtnl_dereference(tfile->tun);
630
631 if (tun && clean) {
632 tun_napi_disable(tfile);
633 tun_napi_del(tfile);
634 }
635
636 if (tun && !tfile->detached) {
637 u16 index = tfile->queue_index;
638 BUG_ON(index >= tun->numqueues);
639
640 rcu_assign_pointer(tun->tfiles[index],
641 tun->tfiles[tun->numqueues - 1]);
642 ntfile = rtnl_dereference(tun->tfiles[index]);
643 ntfile->queue_index = index;
644 rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
645 NULL);
646
647 --tun->numqueues;
648 if (clean) {
649 RCU_INIT_POINTER(tfile->tun, NULL);
650 sock_put(&tfile->sk);
651 } else
652 tun_disable_queue(tun, tfile);
653
654 synchronize_net();
655 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
656 /* Drop read queue */
657 tun_queue_purge(tfile);
658 tun_set_real_num_queues(tun);
659 } else if (tfile->detached && clean) {
660 tun = tun_enable_queue(tfile);
661 sock_put(&tfile->sk);
662 }
663
664 if (clean) {
665 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
666 netif_carrier_off(tun->dev);
667
668 if (!(tun->flags & IFF_PERSIST) &&
669 tun->dev->reg_state == NETREG_REGISTERED)
670 unregister_netdevice(tun->dev);
671 }
672 if (tun)
673 xdp_rxq_info_unreg(&tfile->xdp_rxq);
674 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
675 sock_put(&tfile->sk);
676 }
677}
678
679static void tun_detach(struct tun_file *tfile, bool clean)
680{
681 struct tun_struct *tun;
682 struct net_device *dev;
683
684 rtnl_lock();
685 tun = rtnl_dereference(tfile->tun);
686 dev = tun ? tun->dev : NULL;
687 __tun_detach(tfile, clean);
688 if (dev)
689 netdev_state_change(dev);
690 rtnl_unlock();
691}
692
693static void tun_detach_all(struct net_device *dev)
694{
695 struct tun_struct *tun = netdev_priv(dev);
696 struct tun_file *tfile, *tmp;
697 int i, n = tun->numqueues;
698
699 for (i = 0; i < n; i++) {
700 tfile = rtnl_dereference(tun->tfiles[i]);
701 BUG_ON(!tfile);
702 tun_napi_disable(tfile);
703 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
704 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
705 RCU_INIT_POINTER(tfile->tun, NULL);
706 --tun->numqueues;
707 }
708 list_for_each_entry(tfile, &tun->disabled, next) {
709 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
710 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
711 RCU_INIT_POINTER(tfile->tun, NULL);
712 }
713 BUG_ON(tun->numqueues != 0);
714
715 synchronize_net();
716 for (i = 0; i < n; i++) {
717 tfile = rtnl_dereference(tun->tfiles[i]);
718 tun_napi_del(tfile);
719 /* Drop read queue */
720 tun_queue_purge(tfile);
721 xdp_rxq_info_unreg(&tfile->xdp_rxq);
722 sock_put(&tfile->sk);
723 }
724 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
725 tun_enable_queue(tfile);
726 tun_queue_purge(tfile);
727 xdp_rxq_info_unreg(&tfile->xdp_rxq);
728 sock_put(&tfile->sk);
729 }
730 BUG_ON(tun->numdisabled != 0);
731
732 if (tun->flags & IFF_PERSIST)
733 module_put(THIS_MODULE);
734}
735
736static int tun_attach(struct tun_struct *tun, struct file *file,
737 bool skip_filter, bool napi, bool napi_frags,
738 bool publish_tun)
739{
740 struct tun_file *tfile = file->private_data;
741 struct net_device *dev = tun->dev;
742 int err;
743
744 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
745 if (err < 0)
746 goto out;
747
748 err = -EINVAL;
749 if (rtnl_dereference(tfile->tun) && !tfile->detached)
750 goto out;
751
752 err = -EBUSY;
753 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
754 goto out;
755
756 err = -E2BIG;
757 if (!tfile->detached &&
758 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
759 goto out;
760
761 err = 0;
762
763 /* Re-attach the filter to persist device */
764 if (!skip_filter && (tun->filter_attached == true)) {
765 lock_sock(tfile->socket.sk);
766 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
767 release_sock(tfile->socket.sk);
768 if (!err)
769 goto out;
770 }
771
772 if (!tfile->detached &&
773 ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
774 GFP_KERNEL, tun_ptr_free)) {
775 err = -ENOMEM;
776 goto out;
777 }
778
779 tfile->queue_index = tun->numqueues;
780 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
781
782 if (tfile->detached) {
783 /* Re-attach detached tfile, updating XDP queue_index */
784 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
785
786 if (tfile->xdp_rxq.queue_index != tfile->queue_index)
787 tfile->xdp_rxq.queue_index = tfile->queue_index;
788 } else {
789 /* Setup XDP RX-queue info, for new tfile getting attached */
790 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
791 tun->dev, tfile->queue_index, 0);
792 if (err < 0)
793 goto out;
794 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
795 MEM_TYPE_PAGE_SHARED, NULL);
796 if (err < 0) {
797 xdp_rxq_info_unreg(&tfile->xdp_rxq);
798 goto out;
799 }
800 err = 0;
801 }
802
803 if (tfile->detached) {
804 tun_enable_queue(tfile);
805 } else {
806 sock_hold(&tfile->sk);
807 tun_napi_init(tun, tfile, napi, napi_frags);
808 }
809
810 if (rtnl_dereference(tun->xdp_prog))
811 sock_set_flag(&tfile->sk, SOCK_XDP);
812
813 /* device is allowed to go away first, so no need to hold extra
814 * refcnt.
815 */
816
817 /* Publish tfile->tun and tun->tfiles only after we've fully
818 * initialized tfile; otherwise we risk using half-initialized
819 * object.
820 */
821 if (publish_tun)
822 rcu_assign_pointer(tfile->tun, tun);
823 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
824 tun->numqueues++;
825 tun_set_real_num_queues(tun);
826out:
827 return err;
828}
829
830static struct tun_struct *tun_get(struct tun_file *tfile)
831{
832 struct tun_struct *tun;
833
834 rcu_read_lock();
835 tun = rcu_dereference(tfile->tun);
836 if (tun)
837 dev_hold(tun->dev);
838 rcu_read_unlock();
839
840 return tun;
841}
842
843static void tun_put(struct tun_struct *tun)
844{
845 dev_put(tun->dev);
846}
847
848/* TAP filtering */
849static void addr_hash_set(u32 *mask, const u8 *addr)
850{
851 int n = ether_crc(ETH_ALEN, addr) >> 26;
852 mask[n >> 5] |= (1 << (n & 31));
853}
854
855static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
856{
857 int n = ether_crc(ETH_ALEN, addr) >> 26;
858 return mask[n >> 5] & (1 << (n & 31));
859}
860
861static int update_filter(struct tap_filter *filter, void __user *arg)
862{
863 struct { u8 u[ETH_ALEN]; } *addr;
864 struct tun_filter uf;
865 int err, alen, n, nexact;
866
867 if (copy_from_user(&uf, arg, sizeof(uf)))
868 return -EFAULT;
869
870 if (!uf.count) {
871 /* Disabled */
872 filter->count = 0;
873 return 0;
874 }
875
876 alen = ETH_ALEN * uf.count;
877 addr = memdup_user(arg + sizeof(uf), alen);
878 if (IS_ERR(addr))
879 return PTR_ERR(addr);
880
881 /* The filter is updated without holding any locks. Which is
882 * perfectly safe. We disable it first and in the worst
883 * case we'll accept a few undesired packets. */
884 filter->count = 0;
885 wmb();
886
887 /* Use first set of addresses as an exact filter */
888 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
889 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
890
891 nexact = n;
892
893 /* Remaining multicast addresses are hashed,
894 * unicast will leave the filter disabled. */
895 memset(filter->mask, 0, sizeof(filter->mask));
896 for (; n < uf.count; n++) {
897 if (!is_multicast_ether_addr(addr[n].u)) {
898 err = 0; /* no filter */
899 goto free_addr;
900 }
901 addr_hash_set(filter->mask, addr[n].u);
902 }
903
904 /* For ALLMULTI just set the mask to all ones.
905 * This overrides the mask populated above. */
906 if ((uf.flags & TUN_FLT_ALLMULTI))
907 memset(filter->mask, ~0, sizeof(filter->mask));
908
909 /* Now enable the filter */
910 wmb();
911 filter->count = nexact;
912
913 /* Return the number of exact filters */
914 err = nexact;
915free_addr:
916 kfree(addr);
917 return err;
918}
919
920/* Returns: 0 - drop, !=0 - accept */
921static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
922{
923 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
924 * at this point. */
925 struct ethhdr *eh = (struct ethhdr *) skb->data;
926 int i;
927
928 /* Exact match */
929 for (i = 0; i < filter->count; i++)
930 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
931 return 1;
932
933 /* Inexact match (multicast only) */
934 if (is_multicast_ether_addr(eh->h_dest))
935 return addr_hash_test(filter->mask, eh->h_dest);
936
937 return 0;
938}
939
940/*
941 * Checks whether the packet is accepted or not.
942 * Returns: 0 - drop, !=0 - accept
943 */
944static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
945{
946 if (!filter->count)
947 return 1;
948
949 return run_filter(filter, skb);
950}
951
952/* Network device part of the driver */
953
954static const struct ethtool_ops tun_ethtool_ops;
955
956/* Net device detach from fd. */
957static void tun_net_uninit(struct net_device *dev)
958{
959 tun_detach_all(dev);
960}
961
962/* Net device open. */
963static int tun_net_open(struct net_device *dev)
964{
965 netif_tx_start_all_queues(dev);
966
967 return 0;
968}
969
970/* Net device close. */
971static int tun_net_close(struct net_device *dev)
972{
973 netif_tx_stop_all_queues(dev);
974 return 0;
975}
976
977/* Net device start xmit */
978static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
979{
980#ifdef CONFIG_RPS
981 if (tun->numqueues == 1 && static_branch_unlikely(&rps_needed)) {
982 /* Select queue was not called for the skbuff, so we extract the
983 * RPS hash and save it into the flow_table here.
984 */
985 struct tun_flow_entry *e;
986 __u32 rxhash;
987
988 rxhash = __skb_get_hash_symmetric(skb);
989 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
990 if (e)
991 tun_flow_save_rps_rxhash(e, rxhash);
992 }
993#endif
994}
995
996static unsigned int run_ebpf_filter(struct tun_struct *tun,
997 struct sk_buff *skb,
998 int len)
999{
1000 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1001
1002 if (prog)
1003 len = bpf_prog_run_clear_cb(prog->prog, skb);
1004
1005 return len;
1006}
1007
1008/* Net device start xmit */
1009static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1010{
1011 struct tun_struct *tun = netdev_priv(dev);
1012 int txq = skb->queue_mapping;
1013 struct tun_file *tfile;
1014 int len = skb->len;
1015
1016 rcu_read_lock();
1017 tfile = rcu_dereference(tun->tfiles[txq]);
1018
1019 /* Drop packet if interface is not attached */
1020 if (!tfile)
1021 goto drop;
1022
1023 if (!rcu_dereference(tun->steering_prog))
1024 tun_automq_xmit(tun, skb);
1025
1026 netif_info(tun, tx_queued, tun->dev, "%s %d\n", __func__, skb->len);
1027
1028 /* Drop if the filter does not like it.
1029 * This is a noop if the filter is disabled.
1030 * Filter can be enabled only for the TAP devices. */
1031 if (!check_filter(&tun->txflt, skb))
1032 goto drop;
1033
1034 if (tfile->socket.sk->sk_filter &&
1035 sk_filter(tfile->socket.sk, skb))
1036 goto drop;
1037
1038 len = run_ebpf_filter(tun, skb, len);
1039 if (len == 0 || pskb_trim(skb, len))
1040 goto drop;
1041
1042 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1043 goto drop;
1044
1045 skb_tx_timestamp(skb);
1046
1047 /* Orphan the skb - required as we might hang on to it
1048 * for indefinite time.
1049 */
1050 skb_orphan(skb);
1051
1052 nf_reset_ct(skb);
1053
1054 if (ptr_ring_produce(&tfile->tx_ring, skb))
1055 goto drop;
1056
1057 /* Notify and wake up reader process */
1058 if (tfile->flags & TUN_FASYNC)
1059 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1060 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1061
1062 rcu_read_unlock();
1063 return NETDEV_TX_OK;
1064
1065drop:
1066 atomic_long_inc(&dev->tx_dropped);
1067 skb_tx_error(skb);
1068 kfree_skb(skb);
1069 rcu_read_unlock();
1070 return NET_XMIT_DROP;
1071}
1072
1073static void tun_net_mclist(struct net_device *dev)
1074{
1075 /*
1076 * This callback is supposed to deal with mc filter in
1077 * _rx_ path and has nothing to do with the _tx_ path.
1078 * In rx path we always accept everything userspace gives us.
1079 */
1080}
1081
1082static netdev_features_t tun_net_fix_features(struct net_device *dev,
1083 netdev_features_t features)
1084{
1085 struct tun_struct *tun = netdev_priv(dev);
1086
1087 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1088}
1089
1090static void tun_set_headroom(struct net_device *dev, int new_hr)
1091{
1092 struct tun_struct *tun = netdev_priv(dev);
1093
1094 if (new_hr < NET_SKB_PAD)
1095 new_hr = NET_SKB_PAD;
1096
1097 tun->align = new_hr;
1098}
1099
1100static void
1101tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1102{
1103 struct tun_struct *tun = netdev_priv(dev);
1104
1105 dev_get_tstats64(dev, stats);
1106
1107 stats->rx_frame_errors +=
1108 (unsigned long)atomic_long_read(&tun->rx_frame_errors);
1109}
1110
1111static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1112 struct netlink_ext_ack *extack)
1113{
1114 struct tun_struct *tun = netdev_priv(dev);
1115 struct tun_file *tfile;
1116 struct bpf_prog *old_prog;
1117 int i;
1118
1119 old_prog = rtnl_dereference(tun->xdp_prog);
1120 rcu_assign_pointer(tun->xdp_prog, prog);
1121 if (old_prog)
1122 bpf_prog_put(old_prog);
1123
1124 for (i = 0; i < tun->numqueues; i++) {
1125 tfile = rtnl_dereference(tun->tfiles[i]);
1126 if (prog)
1127 sock_set_flag(&tfile->sk, SOCK_XDP);
1128 else
1129 sock_reset_flag(&tfile->sk, SOCK_XDP);
1130 }
1131 list_for_each_entry(tfile, &tun->disabled, next) {
1132 if (prog)
1133 sock_set_flag(&tfile->sk, SOCK_XDP);
1134 else
1135 sock_reset_flag(&tfile->sk, SOCK_XDP);
1136 }
1137
1138 return 0;
1139}
1140
1141static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1142{
1143 switch (xdp->command) {
1144 case XDP_SETUP_PROG:
1145 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1146 default:
1147 return -EINVAL;
1148 }
1149}
1150
1151static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1152{
1153 if (new_carrier) {
1154 struct tun_struct *tun = netdev_priv(dev);
1155
1156 if (!tun->numqueues)
1157 return -EPERM;
1158
1159 netif_carrier_on(dev);
1160 } else {
1161 netif_carrier_off(dev);
1162 }
1163 return 0;
1164}
1165
1166static const struct net_device_ops tun_netdev_ops = {
1167 .ndo_uninit = tun_net_uninit,
1168 .ndo_open = tun_net_open,
1169 .ndo_stop = tun_net_close,
1170 .ndo_start_xmit = tun_net_xmit,
1171 .ndo_fix_features = tun_net_fix_features,
1172 .ndo_select_queue = tun_select_queue,
1173 .ndo_set_rx_headroom = tun_set_headroom,
1174 .ndo_get_stats64 = tun_net_get_stats64,
1175 .ndo_change_carrier = tun_net_change_carrier,
1176};
1177
1178static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1179{
1180 /* Notify and wake up reader process */
1181 if (tfile->flags & TUN_FASYNC)
1182 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1183 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1184}
1185
1186static int tun_xdp_xmit(struct net_device *dev, int n,
1187 struct xdp_frame **frames, u32 flags)
1188{
1189 struct tun_struct *tun = netdev_priv(dev);
1190 struct tun_file *tfile;
1191 u32 numqueues;
1192 int nxmit = 0;
1193 int i;
1194
1195 if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1196 return -EINVAL;
1197
1198 rcu_read_lock();
1199
1200resample:
1201 numqueues = READ_ONCE(tun->numqueues);
1202 if (!numqueues) {
1203 rcu_read_unlock();
1204 return -ENXIO; /* Caller will free/return all frames */
1205 }
1206
1207 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1208 numqueues]);
1209 if (unlikely(!tfile))
1210 goto resample;
1211
1212 spin_lock(&tfile->tx_ring.producer_lock);
1213 for (i = 0; i < n; i++) {
1214 struct xdp_frame *xdp = frames[i];
1215 /* Encode the XDP flag into lowest bit for consumer to differ
1216 * XDP buffer from sk_buff.
1217 */
1218 void *frame = tun_xdp_to_ptr(xdp);
1219
1220 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1221 atomic_long_inc(&dev->tx_dropped);
1222 break;
1223 }
1224 nxmit++;
1225 }
1226 spin_unlock(&tfile->tx_ring.producer_lock);
1227
1228 if (flags & XDP_XMIT_FLUSH)
1229 __tun_xdp_flush_tfile(tfile);
1230
1231 rcu_read_unlock();
1232 return nxmit;
1233}
1234
1235static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1236{
1237 struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
1238 int nxmit;
1239
1240 if (unlikely(!frame))
1241 return -EOVERFLOW;
1242
1243 nxmit = tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1244 if (!nxmit)
1245 xdp_return_frame_rx_napi(frame);
1246 return nxmit;
1247}
1248
1249static const struct net_device_ops tap_netdev_ops = {
1250 .ndo_uninit = tun_net_uninit,
1251 .ndo_open = tun_net_open,
1252 .ndo_stop = tun_net_close,
1253 .ndo_start_xmit = tun_net_xmit,
1254 .ndo_fix_features = tun_net_fix_features,
1255 .ndo_set_rx_mode = tun_net_mclist,
1256 .ndo_set_mac_address = eth_mac_addr,
1257 .ndo_validate_addr = eth_validate_addr,
1258 .ndo_select_queue = tun_select_queue,
1259 .ndo_features_check = passthru_features_check,
1260 .ndo_set_rx_headroom = tun_set_headroom,
1261 .ndo_get_stats64 = dev_get_tstats64,
1262 .ndo_bpf = tun_xdp,
1263 .ndo_xdp_xmit = tun_xdp_xmit,
1264 .ndo_change_carrier = tun_net_change_carrier,
1265};
1266
1267static void tun_flow_init(struct tun_struct *tun)
1268{
1269 int i;
1270
1271 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1272 INIT_HLIST_HEAD(&tun->flows[i]);
1273
1274 tun->ageing_time = TUN_FLOW_EXPIRE;
1275 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1276 mod_timer(&tun->flow_gc_timer,
1277 round_jiffies_up(jiffies + tun->ageing_time));
1278}
1279
1280static void tun_flow_uninit(struct tun_struct *tun)
1281{
1282 del_timer_sync(&tun->flow_gc_timer);
1283 tun_flow_flush(tun);
1284}
1285
1286#define MIN_MTU 68
1287#define MAX_MTU 65535
1288
1289/* Initialize net device. */
1290static void tun_net_init(struct net_device *dev)
1291{
1292 struct tun_struct *tun = netdev_priv(dev);
1293
1294 switch (tun->flags & TUN_TYPE_MASK) {
1295 case IFF_TUN:
1296 dev->netdev_ops = &tun_netdev_ops;
1297 dev->header_ops = &ip_tunnel_header_ops;
1298
1299 /* Point-to-Point TUN Device */
1300 dev->hard_header_len = 0;
1301 dev->addr_len = 0;
1302 dev->mtu = 1500;
1303
1304 /* Zero header length */
1305 dev->type = ARPHRD_NONE;
1306 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1307 break;
1308
1309 case IFF_TAP:
1310 dev->netdev_ops = &tap_netdev_ops;
1311 /* Ethernet TAP Device */
1312 ether_setup(dev);
1313 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1314 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1315
1316 eth_hw_addr_random(dev);
1317
1318 break;
1319 }
1320
1321 dev->min_mtu = MIN_MTU;
1322 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1323}
1324
1325static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1326{
1327 struct sock *sk = tfile->socket.sk;
1328
1329 return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1330}
1331
1332/* Character device part */
1333
1334/* Poll */
1335static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1336{
1337 struct tun_file *tfile = file->private_data;
1338 struct tun_struct *tun = tun_get(tfile);
1339 struct sock *sk;
1340 __poll_t mask = 0;
1341
1342 if (!tun)
1343 return EPOLLERR;
1344
1345 sk = tfile->socket.sk;
1346
1347 poll_wait(file, sk_sleep(sk), wait);
1348
1349 if (!ptr_ring_empty(&tfile->tx_ring))
1350 mask |= EPOLLIN | EPOLLRDNORM;
1351
1352 /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1353 * guarantee EPOLLOUT to be raised by either here or
1354 * tun_sock_write_space(). Then process could get notification
1355 * after it writes to a down device and meets -EIO.
1356 */
1357 if (tun_sock_writeable(tun, tfile) ||
1358 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1359 tun_sock_writeable(tun, tfile)))
1360 mask |= EPOLLOUT | EPOLLWRNORM;
1361
1362 if (tun->dev->reg_state != NETREG_REGISTERED)
1363 mask = EPOLLERR;
1364
1365 tun_put(tun);
1366 return mask;
1367}
1368
1369static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1370 size_t len,
1371 const struct iov_iter *it)
1372{
1373 struct sk_buff *skb;
1374 size_t linear;
1375 int err;
1376 int i;
1377
1378 if (it->nr_segs > MAX_SKB_FRAGS + 1)
1379 return ERR_PTR(-EMSGSIZE);
1380
1381 local_bh_disable();
1382 skb = napi_get_frags(&tfile->napi);
1383 local_bh_enable();
1384 if (!skb)
1385 return ERR_PTR(-ENOMEM);
1386
1387 linear = iov_iter_single_seg_count(it);
1388 err = __skb_grow(skb, linear);
1389 if (err)
1390 goto free;
1391
1392 skb->len = len;
1393 skb->data_len = len - linear;
1394 skb->truesize += skb->data_len;
1395
1396 for (i = 1; i < it->nr_segs; i++) {
1397 size_t fragsz = it->iov[i].iov_len;
1398 struct page *page;
1399 void *frag;
1400
1401 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1402 err = -EINVAL;
1403 goto free;
1404 }
1405 frag = netdev_alloc_frag(fragsz);
1406 if (!frag) {
1407 err = -ENOMEM;
1408 goto free;
1409 }
1410 page = virt_to_head_page(frag);
1411 skb_fill_page_desc(skb, i - 1, page,
1412 frag - page_address(page), fragsz);
1413 }
1414
1415 return skb;
1416free:
1417 /* frees skb and all frags allocated with napi_alloc_frag() */
1418 napi_free_frags(&tfile->napi);
1419 return ERR_PTR(err);
1420}
1421
1422/* prepad is the amount to reserve at front. len is length after that.
1423 * linear is a hint as to how much to copy (usually headers). */
1424static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1425 size_t prepad, size_t len,
1426 size_t linear, int noblock)
1427{
1428 struct sock *sk = tfile->socket.sk;
1429 struct sk_buff *skb;
1430 int err;
1431
1432 /* Under a page? Don't bother with paged skb. */
1433 if (prepad + len < PAGE_SIZE || !linear)
1434 linear = len;
1435
1436 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1437 &err, 0);
1438 if (!skb)
1439 return ERR_PTR(err);
1440
1441 skb_reserve(skb, prepad);
1442 skb_put(skb, linear);
1443 skb->data_len = len - linear;
1444 skb->len += len - linear;
1445
1446 return skb;
1447}
1448
1449static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1450 struct sk_buff *skb, int more)
1451{
1452 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1453 struct sk_buff_head process_queue;
1454 u32 rx_batched = tun->rx_batched;
1455 bool rcv = false;
1456
1457 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1458 local_bh_disable();
1459 skb_record_rx_queue(skb, tfile->queue_index);
1460 netif_receive_skb(skb);
1461 local_bh_enable();
1462 return;
1463 }
1464
1465 spin_lock(&queue->lock);
1466 if (!more || skb_queue_len(queue) == rx_batched) {
1467 __skb_queue_head_init(&process_queue);
1468 skb_queue_splice_tail_init(queue, &process_queue);
1469 rcv = true;
1470 } else {
1471 __skb_queue_tail(queue, skb);
1472 }
1473 spin_unlock(&queue->lock);
1474
1475 if (rcv) {
1476 struct sk_buff *nskb;
1477
1478 local_bh_disable();
1479 while ((nskb = __skb_dequeue(&process_queue))) {
1480 skb_record_rx_queue(nskb, tfile->queue_index);
1481 netif_receive_skb(nskb);
1482 }
1483 skb_record_rx_queue(skb, tfile->queue_index);
1484 netif_receive_skb(skb);
1485 local_bh_enable();
1486 }
1487}
1488
1489static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1490 int len, int noblock, bool zerocopy)
1491{
1492 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1493 return false;
1494
1495 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1496 return false;
1497
1498 if (!noblock)
1499 return false;
1500
1501 if (zerocopy)
1502 return false;
1503
1504 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1505 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1506 return false;
1507
1508 return true;
1509}
1510
1511static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
1512 struct page_frag *alloc_frag, char *buf,
1513 int buflen, int len, int pad)
1514{
1515 struct sk_buff *skb = build_skb(buf, buflen);
1516
1517 if (!skb)
1518 return ERR_PTR(-ENOMEM);
1519
1520 skb_reserve(skb, pad);
1521 skb_put(skb, len);
1522 skb_set_owner_w(skb, tfile->socket.sk);
1523
1524 get_page(alloc_frag->page);
1525 alloc_frag->offset += buflen;
1526
1527 return skb;
1528}
1529
1530static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1531 struct xdp_buff *xdp, u32 act)
1532{
1533 int err;
1534
1535 switch (act) {
1536 case XDP_REDIRECT:
1537 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1538 if (err)
1539 return err;
1540 break;
1541 case XDP_TX:
1542 err = tun_xdp_tx(tun->dev, xdp);
1543 if (err < 0)
1544 return err;
1545 break;
1546 case XDP_PASS:
1547 break;
1548 default:
1549 bpf_warn_invalid_xdp_action(act);
1550 fallthrough;
1551 case XDP_ABORTED:
1552 trace_xdp_exception(tun->dev, xdp_prog, act);
1553 fallthrough;
1554 case XDP_DROP:
1555 atomic_long_inc(&tun->dev->rx_dropped);
1556 break;
1557 }
1558
1559 return act;
1560}
1561
1562static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1563 struct tun_file *tfile,
1564 struct iov_iter *from,
1565 struct virtio_net_hdr *hdr,
1566 int len, int *skb_xdp)
1567{
1568 struct page_frag *alloc_frag = ¤t->task_frag;
1569 struct bpf_prog *xdp_prog;
1570 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1571 char *buf;
1572 size_t copied;
1573 int pad = TUN_RX_PAD;
1574 int err = 0;
1575
1576 rcu_read_lock();
1577 xdp_prog = rcu_dereference(tun->xdp_prog);
1578 if (xdp_prog)
1579 pad += XDP_PACKET_HEADROOM;
1580 buflen += SKB_DATA_ALIGN(len + pad);
1581 rcu_read_unlock();
1582
1583 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1584 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1585 return ERR_PTR(-ENOMEM);
1586
1587 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1588 copied = copy_page_from_iter(alloc_frag->page,
1589 alloc_frag->offset + pad,
1590 len, from);
1591 if (copied != len)
1592 return ERR_PTR(-EFAULT);
1593
1594 /* There's a small window that XDP may be set after the check
1595 * of xdp_prog above, this should be rare and for simplicity
1596 * we do XDP on skb in case the headroom is not enough.
1597 */
1598 if (hdr->gso_type || !xdp_prog) {
1599 *skb_xdp = 1;
1600 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len,
1601 pad);
1602 }
1603
1604 *skb_xdp = 0;
1605
1606 local_bh_disable();
1607 rcu_read_lock();
1608 xdp_prog = rcu_dereference(tun->xdp_prog);
1609 if (xdp_prog) {
1610 struct xdp_buff xdp;
1611 u32 act;
1612
1613 xdp_init_buff(&xdp, buflen, &tfile->xdp_rxq);
1614 xdp_prepare_buff(&xdp, buf, pad, len, false);
1615
1616 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1617 if (act == XDP_REDIRECT || act == XDP_TX) {
1618 get_page(alloc_frag->page);
1619 alloc_frag->offset += buflen;
1620 }
1621 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1622 if (err < 0) {
1623 if (act == XDP_REDIRECT || act == XDP_TX)
1624 put_page(alloc_frag->page);
1625 goto out;
1626 }
1627
1628 if (err == XDP_REDIRECT)
1629 xdp_do_flush();
1630 if (err != XDP_PASS)
1631 goto out;
1632
1633 pad = xdp.data - xdp.data_hard_start;
1634 len = xdp.data_end - xdp.data;
1635 }
1636 rcu_read_unlock();
1637 local_bh_enable();
1638
1639 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1640
1641out:
1642 rcu_read_unlock();
1643 local_bh_enable();
1644 return NULL;
1645}
1646
1647/* Get packet from user space buffer */
1648static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1649 void *msg_control, struct iov_iter *from,
1650 int noblock, bool more)
1651{
1652 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1653 struct sk_buff *skb;
1654 size_t total_len = iov_iter_count(from);
1655 size_t len = total_len, align = tun->align, linear;
1656 struct virtio_net_hdr gso = { 0 };
1657 int good_linear;
1658 int copylen;
1659 bool zerocopy = false;
1660 int err;
1661 u32 rxhash = 0;
1662 int skb_xdp = 1;
1663 bool frags = tun_napi_frags_enabled(tfile);
1664
1665 if (!(tun->flags & IFF_NO_PI)) {
1666 if (len < sizeof(pi))
1667 return -EINVAL;
1668 len -= sizeof(pi);
1669
1670 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1671 return -EFAULT;
1672 }
1673
1674 if (tun->flags & IFF_VNET_HDR) {
1675 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1676
1677 if (len < vnet_hdr_sz)
1678 return -EINVAL;
1679 len -= vnet_hdr_sz;
1680
1681 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1682 return -EFAULT;
1683
1684 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1685 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1686 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1687
1688 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1689 return -EINVAL;
1690 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1691 }
1692
1693 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1694 align += NET_IP_ALIGN;
1695 if (unlikely(len < ETH_HLEN ||
1696 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1697 return -EINVAL;
1698 }
1699
1700 good_linear = SKB_MAX_HEAD(align);
1701
1702 if (msg_control) {
1703 struct iov_iter i = *from;
1704
1705 /* There are 256 bytes to be copied in skb, so there is
1706 * enough room for skb expand head in case it is used.
1707 * The rest of the buffer is mapped from userspace.
1708 */
1709 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1710 if (copylen > good_linear)
1711 copylen = good_linear;
1712 linear = copylen;
1713 iov_iter_advance(&i, copylen);
1714 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1715 zerocopy = true;
1716 }
1717
1718 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1719 /* For the packet that is not easy to be processed
1720 * (e.g gso or jumbo packet), we will do it at after
1721 * skb was created with generic XDP routine.
1722 */
1723 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1724 if (IS_ERR(skb)) {
1725 atomic_long_inc(&tun->dev->rx_dropped);
1726 return PTR_ERR(skb);
1727 }
1728 if (!skb)
1729 return total_len;
1730 } else {
1731 if (!zerocopy) {
1732 copylen = len;
1733 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1734 linear = good_linear;
1735 else
1736 linear = tun16_to_cpu(tun, gso.hdr_len);
1737 }
1738
1739 if (frags) {
1740 mutex_lock(&tfile->napi_mutex);
1741 skb = tun_napi_alloc_frags(tfile, copylen, from);
1742 /* tun_napi_alloc_frags() enforces a layout for the skb.
1743 * If zerocopy is enabled, then this layout will be
1744 * overwritten by zerocopy_sg_from_iter().
1745 */
1746 zerocopy = false;
1747 } else {
1748 skb = tun_alloc_skb(tfile, align, copylen, linear,
1749 noblock);
1750 }
1751
1752 if (IS_ERR(skb)) {
1753 if (PTR_ERR(skb) != -EAGAIN)
1754 atomic_long_inc(&tun->dev->rx_dropped);
1755 if (frags)
1756 mutex_unlock(&tfile->napi_mutex);
1757 return PTR_ERR(skb);
1758 }
1759
1760 if (zerocopy)
1761 err = zerocopy_sg_from_iter(skb, from);
1762 else
1763 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1764
1765 if (err) {
1766 err = -EFAULT;
1767drop:
1768 atomic_long_inc(&tun->dev->rx_dropped);
1769 kfree_skb(skb);
1770 if (frags) {
1771 tfile->napi.skb = NULL;
1772 mutex_unlock(&tfile->napi_mutex);
1773 }
1774
1775 return err;
1776 }
1777 }
1778
1779 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1780 atomic_long_inc(&tun->rx_frame_errors);
1781 kfree_skb(skb);
1782 if (frags) {
1783 tfile->napi.skb = NULL;
1784 mutex_unlock(&tfile->napi_mutex);
1785 }
1786
1787 return -EINVAL;
1788 }
1789
1790 switch (tun->flags & TUN_TYPE_MASK) {
1791 case IFF_TUN:
1792 if (tun->flags & IFF_NO_PI) {
1793 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1794
1795 switch (ip_version) {
1796 case 4:
1797 pi.proto = htons(ETH_P_IP);
1798 break;
1799 case 6:
1800 pi.proto = htons(ETH_P_IPV6);
1801 break;
1802 default:
1803 atomic_long_inc(&tun->dev->rx_dropped);
1804 kfree_skb(skb);
1805 return -EINVAL;
1806 }
1807 }
1808
1809 skb_reset_mac_header(skb);
1810 skb->protocol = pi.proto;
1811 skb->dev = tun->dev;
1812 break;
1813 case IFF_TAP:
1814 if (frags && !pskb_may_pull(skb, ETH_HLEN)) {
1815 err = -ENOMEM;
1816 goto drop;
1817 }
1818 skb->protocol = eth_type_trans(skb, tun->dev);
1819 break;
1820 }
1821
1822 /* copy skb_ubuf_info for callback when skb has no error */
1823 if (zerocopy) {
1824 skb_zcopy_init(skb, msg_control);
1825 } else if (msg_control) {
1826 struct ubuf_info *uarg = msg_control;
1827 uarg->callback(NULL, uarg, false);
1828 }
1829
1830 skb_reset_network_header(skb);
1831 skb_probe_transport_header(skb);
1832 skb_record_rx_queue(skb, tfile->queue_index);
1833
1834 if (skb_xdp) {
1835 struct bpf_prog *xdp_prog;
1836 int ret;
1837
1838 local_bh_disable();
1839 rcu_read_lock();
1840 xdp_prog = rcu_dereference(tun->xdp_prog);
1841 if (xdp_prog) {
1842 ret = do_xdp_generic(xdp_prog, skb);
1843 if (ret != XDP_PASS) {
1844 rcu_read_unlock();
1845 local_bh_enable();
1846 if (frags) {
1847 tfile->napi.skb = NULL;
1848 mutex_unlock(&tfile->napi_mutex);
1849 }
1850 return total_len;
1851 }
1852 }
1853 rcu_read_unlock();
1854 local_bh_enable();
1855 }
1856
1857 /* Compute the costly rx hash only if needed for flow updates.
1858 * We may get a very small possibility of OOO during switching, not
1859 * worth to optimize.
1860 */
1861 if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1862 !tfile->detached)
1863 rxhash = __skb_get_hash_symmetric(skb);
1864
1865 rcu_read_lock();
1866 if (unlikely(!(tun->dev->flags & IFF_UP))) {
1867 err = -EIO;
1868 rcu_read_unlock();
1869 goto drop;
1870 }
1871
1872 if (frags) {
1873 u32 headlen;
1874
1875 /* Exercise flow dissector code path. */
1876 skb_push(skb, ETH_HLEN);
1877 headlen = eth_get_headlen(tun->dev, skb->data,
1878 skb_headlen(skb));
1879
1880 if (unlikely(headlen > skb_headlen(skb))) {
1881 atomic_long_inc(&tun->dev->rx_dropped);
1882 napi_free_frags(&tfile->napi);
1883 rcu_read_unlock();
1884 mutex_unlock(&tfile->napi_mutex);
1885 WARN_ON(1);
1886 return -ENOMEM;
1887 }
1888
1889 local_bh_disable();
1890 napi_gro_frags(&tfile->napi);
1891 local_bh_enable();
1892 mutex_unlock(&tfile->napi_mutex);
1893 } else if (tfile->napi_enabled) {
1894 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1895 int queue_len;
1896
1897 spin_lock_bh(&queue->lock);
1898 __skb_queue_tail(queue, skb);
1899 queue_len = skb_queue_len(queue);
1900 spin_unlock(&queue->lock);
1901
1902 if (!more || queue_len > NAPI_POLL_WEIGHT)
1903 napi_schedule(&tfile->napi);
1904
1905 local_bh_enable();
1906 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1907 tun_rx_batched(tun, tfile, skb, more);
1908 } else {
1909 netif_rx_ni(skb);
1910 }
1911 rcu_read_unlock();
1912
1913 preempt_disable();
1914 dev_sw_netstats_rx_add(tun->dev, len);
1915 preempt_enable();
1916
1917 if (rxhash)
1918 tun_flow_update(tun, rxhash, tfile);
1919
1920 return total_len;
1921}
1922
1923static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1924{
1925 struct file *file = iocb->ki_filp;
1926 struct tun_file *tfile = file->private_data;
1927 struct tun_struct *tun = tun_get(tfile);
1928 ssize_t result;
1929 int noblock = 0;
1930
1931 if (!tun)
1932 return -EBADFD;
1933
1934 if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
1935 noblock = 1;
1936
1937 result = tun_get_user(tun, tfile, NULL, from, noblock, false);
1938
1939 tun_put(tun);
1940 return result;
1941}
1942
1943static ssize_t tun_put_user_xdp(struct tun_struct *tun,
1944 struct tun_file *tfile,
1945 struct xdp_frame *xdp_frame,
1946 struct iov_iter *iter)
1947{
1948 int vnet_hdr_sz = 0;
1949 size_t size = xdp_frame->len;
1950 size_t ret;
1951
1952 if (tun->flags & IFF_VNET_HDR) {
1953 struct virtio_net_hdr gso = { 0 };
1954
1955 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1956 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
1957 return -EINVAL;
1958 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
1959 sizeof(gso)))
1960 return -EFAULT;
1961 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1962 }
1963
1964 ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
1965
1966 preempt_disable();
1967 dev_sw_netstats_tx_add(tun->dev, 1, ret);
1968 preempt_enable();
1969
1970 return ret;
1971}
1972
1973/* Put packet to the user space buffer */
1974static ssize_t tun_put_user(struct tun_struct *tun,
1975 struct tun_file *tfile,
1976 struct sk_buff *skb,
1977 struct iov_iter *iter)
1978{
1979 struct tun_pi pi = { 0, skb->protocol };
1980 ssize_t total;
1981 int vlan_offset = 0;
1982 int vlan_hlen = 0;
1983 int vnet_hdr_sz = 0;
1984
1985 if (skb_vlan_tag_present(skb))
1986 vlan_hlen = VLAN_HLEN;
1987
1988 if (tun->flags & IFF_VNET_HDR)
1989 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1990
1991 total = skb->len + vlan_hlen + vnet_hdr_sz;
1992
1993 if (!(tun->flags & IFF_NO_PI)) {
1994 if (iov_iter_count(iter) < sizeof(pi))
1995 return -EINVAL;
1996
1997 total += sizeof(pi);
1998 if (iov_iter_count(iter) < total) {
1999 /* Packet will be striped */
2000 pi.flags |= TUN_PKT_STRIP;
2001 }
2002
2003 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2004 return -EFAULT;
2005 }
2006
2007 if (vnet_hdr_sz) {
2008 struct virtio_net_hdr gso;
2009
2010 if (iov_iter_count(iter) < vnet_hdr_sz)
2011 return -EINVAL;
2012
2013 if (virtio_net_hdr_from_skb(skb, &gso,
2014 tun_is_little_endian(tun), true,
2015 vlan_hlen)) {
2016 struct skb_shared_info *sinfo = skb_shinfo(skb);
2017 pr_err("unexpected GSO type: "
2018 "0x%x, gso_size %d, hdr_len %d\n",
2019 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2020 tun16_to_cpu(tun, gso.hdr_len));
2021 print_hex_dump(KERN_ERR, "tun: ",
2022 DUMP_PREFIX_NONE,
2023 16, 1, skb->head,
2024 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2025 WARN_ON_ONCE(1);
2026 return -EINVAL;
2027 }
2028
2029 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2030 return -EFAULT;
2031
2032 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2033 }
2034
2035 if (vlan_hlen) {
2036 int ret;
2037 struct veth veth;
2038
2039 veth.h_vlan_proto = skb->vlan_proto;
2040 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2041
2042 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2043
2044 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2045 if (ret || !iov_iter_count(iter))
2046 goto done;
2047
2048 ret = copy_to_iter(&veth, sizeof(veth), iter);
2049 if (ret != sizeof(veth) || !iov_iter_count(iter))
2050 goto done;
2051 }
2052
2053 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2054
2055done:
2056 /* caller is in process context, */
2057 preempt_disable();
2058 dev_sw_netstats_tx_add(tun->dev, 1, skb->len + vlan_hlen);
2059 preempt_enable();
2060
2061 return total;
2062}
2063
2064static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2065{
2066 DECLARE_WAITQUEUE(wait, current);
2067 void *ptr = NULL;
2068 int error = 0;
2069
2070 ptr = ptr_ring_consume(&tfile->tx_ring);
2071 if (ptr)
2072 goto out;
2073 if (noblock) {
2074 error = -EAGAIN;
2075 goto out;
2076 }
2077
2078 add_wait_queue(&tfile->socket.wq.wait, &wait);
2079
2080 while (1) {
2081 set_current_state(TASK_INTERRUPTIBLE);
2082 ptr = ptr_ring_consume(&tfile->tx_ring);
2083 if (ptr)
2084 break;
2085 if (signal_pending(current)) {
2086 error = -ERESTARTSYS;
2087 break;
2088 }
2089 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2090 error = -EFAULT;
2091 break;
2092 }
2093
2094 schedule();
2095 }
2096
2097 __set_current_state(TASK_RUNNING);
2098 remove_wait_queue(&tfile->socket.wq.wait, &wait);
2099
2100out:
2101 *err = error;
2102 return ptr;
2103}
2104
2105static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2106 struct iov_iter *to,
2107 int noblock, void *ptr)
2108{
2109 ssize_t ret;
2110 int err;
2111
2112 if (!iov_iter_count(to)) {
2113 tun_ptr_free(ptr);
2114 return 0;
2115 }
2116
2117 if (!ptr) {
2118 /* Read frames from ring */
2119 ptr = tun_ring_recv(tfile, noblock, &err);
2120 if (!ptr)
2121 return err;
2122 }
2123
2124 if (tun_is_xdp_frame(ptr)) {
2125 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2126
2127 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2128 xdp_return_frame(xdpf);
2129 } else {
2130 struct sk_buff *skb = ptr;
2131
2132 ret = tun_put_user(tun, tfile, skb, to);
2133 if (unlikely(ret < 0))
2134 kfree_skb(skb);
2135 else
2136 consume_skb(skb);
2137 }
2138
2139 return ret;
2140}
2141
2142static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2143{
2144 struct file *file = iocb->ki_filp;
2145 struct tun_file *tfile = file->private_data;
2146 struct tun_struct *tun = tun_get(tfile);
2147 ssize_t len = iov_iter_count(to), ret;
2148 int noblock = 0;
2149
2150 if (!tun)
2151 return -EBADFD;
2152
2153 if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
2154 noblock = 1;
2155
2156 ret = tun_do_read(tun, tfile, to, noblock, NULL);
2157 ret = min_t(ssize_t, ret, len);
2158 if (ret > 0)
2159 iocb->ki_pos = ret;
2160 tun_put(tun);
2161 return ret;
2162}
2163
2164static void tun_prog_free(struct rcu_head *rcu)
2165{
2166 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2167
2168 bpf_prog_destroy(prog->prog);
2169 kfree(prog);
2170}
2171
2172static int __tun_set_ebpf(struct tun_struct *tun,
2173 struct tun_prog __rcu **prog_p,
2174 struct bpf_prog *prog)
2175{
2176 struct tun_prog *old, *new = NULL;
2177
2178 if (prog) {
2179 new = kmalloc(sizeof(*new), GFP_KERNEL);
2180 if (!new)
2181 return -ENOMEM;
2182 new->prog = prog;
2183 }
2184
2185 spin_lock_bh(&tun->lock);
2186 old = rcu_dereference_protected(*prog_p,
2187 lockdep_is_held(&tun->lock));
2188 rcu_assign_pointer(*prog_p, new);
2189 spin_unlock_bh(&tun->lock);
2190
2191 if (old)
2192 call_rcu(&old->rcu, tun_prog_free);
2193
2194 return 0;
2195}
2196
2197static void tun_free_netdev(struct net_device *dev)
2198{
2199 struct tun_struct *tun = netdev_priv(dev);
2200
2201 BUG_ON(!(list_empty(&tun->disabled)));
2202
2203 free_percpu(dev->tstats);
2204 /* We clear tstats so that tun_set_iff() can tell if
2205 * tun_free_netdev() has been called from register_netdevice().
2206 */
2207 dev->tstats = NULL;
2208
2209 tun_flow_uninit(tun);
2210 security_tun_dev_free_security(tun->security);
2211 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2212 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2213}
2214
2215static void tun_setup(struct net_device *dev)
2216{
2217 struct tun_struct *tun = netdev_priv(dev);
2218
2219 tun->owner = INVALID_UID;
2220 tun->group = INVALID_GID;
2221 tun_default_link_ksettings(dev, &tun->link_ksettings);
2222
2223 dev->ethtool_ops = &tun_ethtool_ops;
2224 dev->needs_free_netdev = true;
2225 dev->priv_destructor = tun_free_netdev;
2226 /* We prefer our own queue length */
2227 dev->tx_queue_len = TUN_READQ_SIZE;
2228}
2229
2230/* Trivial set of netlink ops to allow deleting tun or tap
2231 * device with netlink.
2232 */
2233static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2234 struct netlink_ext_ack *extack)
2235{
2236 NL_SET_ERR_MSG(extack,
2237 "tun/tap creation via rtnetlink is not supported.");
2238 return -EOPNOTSUPP;
2239}
2240
2241static size_t tun_get_size(const struct net_device *dev)
2242{
2243 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2244 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2245
2246 return nla_total_size(sizeof(uid_t)) + /* OWNER */
2247 nla_total_size(sizeof(gid_t)) + /* GROUP */
2248 nla_total_size(sizeof(u8)) + /* TYPE */
2249 nla_total_size(sizeof(u8)) + /* PI */
2250 nla_total_size(sizeof(u8)) + /* VNET_HDR */
2251 nla_total_size(sizeof(u8)) + /* PERSIST */
2252 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2253 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2254 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2255 0;
2256}
2257
2258static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2259{
2260 struct tun_struct *tun = netdev_priv(dev);
2261
2262 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2263 goto nla_put_failure;
2264 if (uid_valid(tun->owner) &&
2265 nla_put_u32(skb, IFLA_TUN_OWNER,
2266 from_kuid_munged(current_user_ns(), tun->owner)))
2267 goto nla_put_failure;
2268 if (gid_valid(tun->group) &&
2269 nla_put_u32(skb, IFLA_TUN_GROUP,
2270 from_kgid_munged(current_user_ns(), tun->group)))
2271 goto nla_put_failure;
2272 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2273 goto nla_put_failure;
2274 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2275 goto nla_put_failure;
2276 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2277 goto nla_put_failure;
2278 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2279 !!(tun->flags & IFF_MULTI_QUEUE)))
2280 goto nla_put_failure;
2281 if (tun->flags & IFF_MULTI_QUEUE) {
2282 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2283 goto nla_put_failure;
2284 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2285 tun->numdisabled))
2286 goto nla_put_failure;
2287 }
2288
2289 return 0;
2290
2291nla_put_failure:
2292 return -EMSGSIZE;
2293}
2294
2295static struct rtnl_link_ops tun_link_ops __read_mostly = {
2296 .kind = DRV_NAME,
2297 .priv_size = sizeof(struct tun_struct),
2298 .setup = tun_setup,
2299 .validate = tun_validate,
2300 .get_size = tun_get_size,
2301 .fill_info = tun_fill_info,
2302};
2303
2304static void tun_sock_write_space(struct sock *sk)
2305{
2306 struct tun_file *tfile;
2307 wait_queue_head_t *wqueue;
2308
2309 if (!sock_writeable(sk))
2310 return;
2311
2312 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2313 return;
2314
2315 wqueue = sk_sleep(sk);
2316 if (wqueue && waitqueue_active(wqueue))
2317 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2318 EPOLLWRNORM | EPOLLWRBAND);
2319
2320 tfile = container_of(sk, struct tun_file, sk);
2321 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2322}
2323
2324static void tun_put_page(struct tun_page *tpage)
2325{
2326 if (tpage->page)
2327 __page_frag_cache_drain(tpage->page, tpage->count);
2328}
2329
2330static int tun_xdp_one(struct tun_struct *tun,
2331 struct tun_file *tfile,
2332 struct xdp_buff *xdp, int *flush,
2333 struct tun_page *tpage)
2334{
2335 unsigned int datasize = xdp->data_end - xdp->data;
2336 struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2337 struct virtio_net_hdr *gso = &hdr->gso;
2338 struct bpf_prog *xdp_prog;
2339 struct sk_buff *skb = NULL;
2340 u32 rxhash = 0, act;
2341 int buflen = hdr->buflen;
2342 int err = 0;
2343 bool skb_xdp = false;
2344 struct page *page;
2345
2346 xdp_prog = rcu_dereference(tun->xdp_prog);
2347 if (xdp_prog) {
2348 if (gso->gso_type) {
2349 skb_xdp = true;
2350 goto build;
2351 }
2352
2353 xdp_init_buff(xdp, buflen, &tfile->xdp_rxq);
2354 xdp_set_data_meta_invalid(xdp);
2355
2356 act = bpf_prog_run_xdp(xdp_prog, xdp);
2357 err = tun_xdp_act(tun, xdp_prog, xdp, act);
2358 if (err < 0) {
2359 put_page(virt_to_head_page(xdp->data));
2360 return err;
2361 }
2362
2363 switch (err) {
2364 case XDP_REDIRECT:
2365 *flush = true;
2366 fallthrough;
2367 case XDP_TX:
2368 return 0;
2369 case XDP_PASS:
2370 break;
2371 default:
2372 page = virt_to_head_page(xdp->data);
2373 if (tpage->page == page) {
2374 ++tpage->count;
2375 } else {
2376 tun_put_page(tpage);
2377 tpage->page = page;
2378 tpage->count = 1;
2379 }
2380 return 0;
2381 }
2382 }
2383
2384build:
2385 skb = build_skb(xdp->data_hard_start, buflen);
2386 if (!skb) {
2387 err = -ENOMEM;
2388 goto out;
2389 }
2390
2391 skb_reserve(skb, xdp->data - xdp->data_hard_start);
2392 skb_put(skb, xdp->data_end - xdp->data);
2393
2394 if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2395 atomic_long_inc(&tun->rx_frame_errors);
2396 kfree_skb(skb);
2397 err = -EINVAL;
2398 goto out;
2399 }
2400
2401 skb->protocol = eth_type_trans(skb, tun->dev);
2402 skb_reset_network_header(skb);
2403 skb_probe_transport_header(skb);
2404 skb_record_rx_queue(skb, tfile->queue_index);
2405
2406 if (skb_xdp) {
2407 err = do_xdp_generic(xdp_prog, skb);
2408 if (err != XDP_PASS)
2409 goto out;
2410 }
2411
2412 if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2413 !tfile->detached)
2414 rxhash = __skb_get_hash_symmetric(skb);
2415
2416 netif_receive_skb(skb);
2417
2418 /* No need to disable preemption here since this function is
2419 * always called with bh disabled
2420 */
2421 dev_sw_netstats_rx_add(tun->dev, datasize);
2422
2423 if (rxhash)
2424 tun_flow_update(tun, rxhash, tfile);
2425
2426out:
2427 return err;
2428}
2429
2430static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2431{
2432 int ret, i;
2433 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2434 struct tun_struct *tun = tun_get(tfile);
2435 struct tun_msg_ctl *ctl = m->msg_control;
2436 struct xdp_buff *xdp;
2437
2438 if (!tun)
2439 return -EBADFD;
2440
2441 if (ctl && (ctl->type == TUN_MSG_PTR)) {
2442 struct tun_page tpage;
2443 int n = ctl->num;
2444 int flush = 0;
2445
2446 memset(&tpage, 0, sizeof(tpage));
2447
2448 local_bh_disable();
2449 rcu_read_lock();
2450
2451 for (i = 0; i < n; i++) {
2452 xdp = &((struct xdp_buff *)ctl->ptr)[i];
2453 tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2454 }
2455
2456 if (flush)
2457 xdp_do_flush();
2458
2459 rcu_read_unlock();
2460 local_bh_enable();
2461
2462 tun_put_page(&tpage);
2463
2464 ret = total_len;
2465 goto out;
2466 }
2467
2468 ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2469 m->msg_flags & MSG_DONTWAIT,
2470 m->msg_flags & MSG_MORE);
2471out:
2472 tun_put(tun);
2473 return ret;
2474}
2475
2476static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2477 int flags)
2478{
2479 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2480 struct tun_struct *tun = tun_get(tfile);
2481 void *ptr = m->msg_control;
2482 int ret;
2483
2484 if (!tun) {
2485 ret = -EBADFD;
2486 goto out_free;
2487 }
2488
2489 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2490 ret = -EINVAL;
2491 goto out_put_tun;
2492 }
2493 if (flags & MSG_ERRQUEUE) {
2494 ret = sock_recv_errqueue(sock->sk, m, total_len,
2495 SOL_PACKET, TUN_TX_TIMESTAMP);
2496 goto out;
2497 }
2498 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2499 if (ret > (ssize_t)total_len) {
2500 m->msg_flags |= MSG_TRUNC;
2501 ret = flags & MSG_TRUNC ? ret : total_len;
2502 }
2503out:
2504 tun_put(tun);
2505 return ret;
2506
2507out_put_tun:
2508 tun_put(tun);
2509out_free:
2510 tun_ptr_free(ptr);
2511 return ret;
2512}
2513
2514static int tun_ptr_peek_len(void *ptr)
2515{
2516 if (likely(ptr)) {
2517 if (tun_is_xdp_frame(ptr)) {
2518 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2519
2520 return xdpf->len;
2521 }
2522 return __skb_array_len_with_tag(ptr);
2523 } else {
2524 return 0;
2525 }
2526}
2527
2528static int tun_peek_len(struct socket *sock)
2529{
2530 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2531 struct tun_struct *tun;
2532 int ret = 0;
2533
2534 tun = tun_get(tfile);
2535 if (!tun)
2536 return 0;
2537
2538 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2539 tun_put(tun);
2540
2541 return ret;
2542}
2543
2544/* Ops structure to mimic raw sockets with tun */
2545static const struct proto_ops tun_socket_ops = {
2546 .peek_len = tun_peek_len,
2547 .sendmsg = tun_sendmsg,
2548 .recvmsg = tun_recvmsg,
2549};
2550
2551static struct proto tun_proto = {
2552 .name = "tun",
2553 .owner = THIS_MODULE,
2554 .obj_size = sizeof(struct tun_file),
2555};
2556
2557static int tun_flags(struct tun_struct *tun)
2558{
2559 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2560}
2561
2562static ssize_t tun_flags_show(struct device *dev, struct device_attribute *attr,
2563 char *buf)
2564{
2565 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2566 return sprintf(buf, "0x%x\n", tun_flags(tun));
2567}
2568
2569static ssize_t owner_show(struct device *dev, struct device_attribute *attr,
2570 char *buf)
2571{
2572 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2573 return uid_valid(tun->owner)?
2574 sprintf(buf, "%u\n",
2575 from_kuid_munged(current_user_ns(), tun->owner)):
2576 sprintf(buf, "-1\n");
2577}
2578
2579static ssize_t group_show(struct device *dev, struct device_attribute *attr,
2580 char *buf)
2581{
2582 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2583 return gid_valid(tun->group) ?
2584 sprintf(buf, "%u\n",
2585 from_kgid_munged(current_user_ns(), tun->group)):
2586 sprintf(buf, "-1\n");
2587}
2588
2589static DEVICE_ATTR_RO(tun_flags);
2590static DEVICE_ATTR_RO(owner);
2591static DEVICE_ATTR_RO(group);
2592
2593static struct attribute *tun_dev_attrs[] = {
2594 &dev_attr_tun_flags.attr,
2595 &dev_attr_owner.attr,
2596 &dev_attr_group.attr,
2597 NULL
2598};
2599
2600static const struct attribute_group tun_attr_group = {
2601 .attrs = tun_dev_attrs
2602};
2603
2604static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2605{
2606 struct tun_struct *tun;
2607 struct tun_file *tfile = file->private_data;
2608 struct net_device *dev;
2609 int err;
2610
2611 if (tfile->detached)
2612 return -EINVAL;
2613
2614 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2615 if (!capable(CAP_NET_ADMIN))
2616 return -EPERM;
2617
2618 if (!(ifr->ifr_flags & IFF_NAPI) ||
2619 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2620 return -EINVAL;
2621 }
2622
2623 dev = __dev_get_by_name(net, ifr->ifr_name);
2624 if (dev) {
2625 if (ifr->ifr_flags & IFF_TUN_EXCL)
2626 return -EBUSY;
2627 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2628 tun = netdev_priv(dev);
2629 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2630 tun = netdev_priv(dev);
2631 else
2632 return -EINVAL;
2633
2634 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2635 !!(tun->flags & IFF_MULTI_QUEUE))
2636 return -EINVAL;
2637
2638 if (tun_not_capable(tun))
2639 return -EPERM;
2640 err = security_tun_dev_open(tun->security);
2641 if (err < 0)
2642 return err;
2643
2644 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2645 ifr->ifr_flags & IFF_NAPI,
2646 ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2647 if (err < 0)
2648 return err;
2649
2650 if (tun->flags & IFF_MULTI_QUEUE &&
2651 (tun->numqueues + tun->numdisabled > 1)) {
2652 /* One or more queue has already been attached, no need
2653 * to initialize the device again.
2654 */
2655 netdev_state_change(dev);
2656 return 0;
2657 }
2658
2659 tun->flags = (tun->flags & ~TUN_FEATURES) |
2660 (ifr->ifr_flags & TUN_FEATURES);
2661
2662 netdev_state_change(dev);
2663 } else {
2664 char *name;
2665 unsigned long flags = 0;
2666 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2667 MAX_TAP_QUEUES : 1;
2668
2669 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2670 return -EPERM;
2671 err = security_tun_dev_create();
2672 if (err < 0)
2673 return err;
2674
2675 /* Set dev type */
2676 if (ifr->ifr_flags & IFF_TUN) {
2677 /* TUN device */
2678 flags |= IFF_TUN;
2679 name = "tun%d";
2680 } else if (ifr->ifr_flags & IFF_TAP) {
2681 /* TAP device */
2682 flags |= IFF_TAP;
2683 name = "tap%d";
2684 } else
2685 return -EINVAL;
2686
2687 if (*ifr->ifr_name)
2688 name = ifr->ifr_name;
2689
2690 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2691 NET_NAME_UNKNOWN, tun_setup, queues,
2692 queues);
2693
2694 if (!dev)
2695 return -ENOMEM;
2696
2697 dev_net_set(dev, net);
2698 dev->rtnl_link_ops = &tun_link_ops;
2699 dev->ifindex = tfile->ifindex;
2700 dev->sysfs_groups[0] = &tun_attr_group;
2701
2702 tun = netdev_priv(dev);
2703 tun->dev = dev;
2704 tun->flags = flags;
2705 tun->txflt.count = 0;
2706 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2707
2708 tun->align = NET_SKB_PAD;
2709 tun->filter_attached = false;
2710 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2711 tun->rx_batched = 0;
2712 RCU_INIT_POINTER(tun->steering_prog, NULL);
2713
2714 dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
2715 if (!dev->tstats) {
2716 err = -ENOMEM;
2717 goto err_free_dev;
2718 }
2719
2720 spin_lock_init(&tun->lock);
2721
2722 err = security_tun_dev_alloc_security(&tun->security);
2723 if (err < 0)
2724 goto err_free_stat;
2725
2726 tun_net_init(dev);
2727 tun_flow_init(tun);
2728
2729 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2730 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2731 NETIF_F_HW_VLAN_STAG_TX;
2732 dev->features = dev->hw_features | NETIF_F_LLTX;
2733 dev->vlan_features = dev->features &
2734 ~(NETIF_F_HW_VLAN_CTAG_TX |
2735 NETIF_F_HW_VLAN_STAG_TX);
2736
2737 tun->flags = (tun->flags & ~TUN_FEATURES) |
2738 (ifr->ifr_flags & TUN_FEATURES);
2739
2740 INIT_LIST_HEAD(&tun->disabled);
2741 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI,
2742 ifr->ifr_flags & IFF_NAPI_FRAGS, false);
2743 if (err < 0)
2744 goto err_free_flow;
2745
2746 err = register_netdevice(tun->dev);
2747 if (err < 0)
2748 goto err_detach;
2749 /* free_netdev() won't check refcnt, to avoid race
2750 * with dev_put() we need publish tun after registration.
2751 */
2752 rcu_assign_pointer(tfile->tun, tun);
2753 }
2754
2755 netif_carrier_on(tun->dev);
2756
2757 /* Make sure persistent devices do not get stuck in
2758 * xoff state.
2759 */
2760 if (netif_running(tun->dev))
2761 netif_tx_wake_all_queues(tun->dev);
2762
2763 strcpy(ifr->ifr_name, tun->dev->name);
2764 return 0;
2765
2766err_detach:
2767 tun_detach_all(dev);
2768 /* We are here because register_netdevice() has failed.
2769 * If register_netdevice() already called tun_free_netdev()
2770 * while dealing with the error, dev->stats has been cleared.
2771 */
2772 if (!dev->tstats)
2773 goto err_free_dev;
2774
2775err_free_flow:
2776 tun_flow_uninit(tun);
2777 security_tun_dev_free_security(tun->security);
2778err_free_stat:
2779 free_percpu(dev->tstats);
2780err_free_dev:
2781 free_netdev(dev);
2782 return err;
2783}
2784
2785static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2786{
2787 strcpy(ifr->ifr_name, tun->dev->name);
2788
2789 ifr->ifr_flags = tun_flags(tun);
2790
2791}
2792
2793/* This is like a cut-down ethtool ops, except done via tun fd so no
2794 * privs required. */
2795static int set_offload(struct tun_struct *tun, unsigned long arg)
2796{
2797 netdev_features_t features = 0;
2798
2799 if (arg & TUN_F_CSUM) {
2800 features |= NETIF_F_HW_CSUM;
2801 arg &= ~TUN_F_CSUM;
2802
2803 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2804 if (arg & TUN_F_TSO_ECN) {
2805 features |= NETIF_F_TSO_ECN;
2806 arg &= ~TUN_F_TSO_ECN;
2807 }
2808 if (arg & TUN_F_TSO4)
2809 features |= NETIF_F_TSO;
2810 if (arg & TUN_F_TSO6)
2811 features |= NETIF_F_TSO6;
2812 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2813 }
2814
2815 arg &= ~TUN_F_UFO;
2816 }
2817
2818 /* This gives the user a way to test for new features in future by
2819 * trying to set them. */
2820 if (arg)
2821 return -EINVAL;
2822
2823 tun->set_features = features;
2824 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2825 tun->dev->wanted_features |= features;
2826 netdev_update_features(tun->dev);
2827
2828 return 0;
2829}
2830
2831static void tun_detach_filter(struct tun_struct *tun, int n)
2832{
2833 int i;
2834 struct tun_file *tfile;
2835
2836 for (i = 0; i < n; i++) {
2837 tfile = rtnl_dereference(tun->tfiles[i]);
2838 lock_sock(tfile->socket.sk);
2839 sk_detach_filter(tfile->socket.sk);
2840 release_sock(tfile->socket.sk);
2841 }
2842
2843 tun->filter_attached = false;
2844}
2845
2846static int tun_attach_filter(struct tun_struct *tun)
2847{
2848 int i, ret = 0;
2849 struct tun_file *tfile;
2850
2851 for (i = 0; i < tun->numqueues; i++) {
2852 tfile = rtnl_dereference(tun->tfiles[i]);
2853 lock_sock(tfile->socket.sk);
2854 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2855 release_sock(tfile->socket.sk);
2856 if (ret) {
2857 tun_detach_filter(tun, i);
2858 return ret;
2859 }
2860 }
2861
2862 tun->filter_attached = true;
2863 return ret;
2864}
2865
2866static void tun_set_sndbuf(struct tun_struct *tun)
2867{
2868 struct tun_file *tfile;
2869 int i;
2870
2871 for (i = 0; i < tun->numqueues; i++) {
2872 tfile = rtnl_dereference(tun->tfiles[i]);
2873 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2874 }
2875}
2876
2877static int tun_set_queue(struct file *file, struct ifreq *ifr)
2878{
2879 struct tun_file *tfile = file->private_data;
2880 struct tun_struct *tun;
2881 int ret = 0;
2882
2883 rtnl_lock();
2884
2885 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2886 tun = tfile->detached;
2887 if (!tun) {
2888 ret = -EINVAL;
2889 goto unlock;
2890 }
2891 ret = security_tun_dev_attach_queue(tun->security);
2892 if (ret < 0)
2893 goto unlock;
2894 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2895 tun->flags & IFF_NAPI_FRAGS, true);
2896 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2897 tun = rtnl_dereference(tfile->tun);
2898 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2899 ret = -EINVAL;
2900 else
2901 __tun_detach(tfile, false);
2902 } else
2903 ret = -EINVAL;
2904
2905 if (ret >= 0)
2906 netdev_state_change(tun->dev);
2907
2908unlock:
2909 rtnl_unlock();
2910 return ret;
2911}
2912
2913static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog __rcu **prog_p,
2914 void __user *data)
2915{
2916 struct bpf_prog *prog;
2917 int fd;
2918
2919 if (copy_from_user(&fd, data, sizeof(fd)))
2920 return -EFAULT;
2921
2922 if (fd == -1) {
2923 prog = NULL;
2924 } else {
2925 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
2926 if (IS_ERR(prog))
2927 return PTR_ERR(prog);
2928 }
2929
2930 return __tun_set_ebpf(tun, prog_p, prog);
2931}
2932
2933/* Return correct value for tun->dev->addr_len based on tun->dev->type. */
2934static unsigned char tun_get_addr_len(unsigned short type)
2935{
2936 switch (type) {
2937 case ARPHRD_IP6GRE:
2938 case ARPHRD_TUNNEL6:
2939 return sizeof(struct in6_addr);
2940 case ARPHRD_IPGRE:
2941 case ARPHRD_TUNNEL:
2942 case ARPHRD_SIT:
2943 return 4;
2944 case ARPHRD_ETHER:
2945 return ETH_ALEN;
2946 case ARPHRD_IEEE802154:
2947 case ARPHRD_IEEE802154_MONITOR:
2948 return IEEE802154_EXTENDED_ADDR_LEN;
2949 case ARPHRD_PHONET_PIPE:
2950 case ARPHRD_PPP:
2951 case ARPHRD_NONE:
2952 return 0;
2953 case ARPHRD_6LOWPAN:
2954 return EUI64_ADDR_LEN;
2955 case ARPHRD_FDDI:
2956 return FDDI_K_ALEN;
2957 case ARPHRD_HIPPI:
2958 return HIPPI_ALEN;
2959 case ARPHRD_IEEE802:
2960 return FC_ALEN;
2961 case ARPHRD_ROSE:
2962 return ROSE_ADDR_LEN;
2963 case ARPHRD_NETROM:
2964 return AX25_ADDR_LEN;
2965 case ARPHRD_LOCALTLK:
2966 return LTALK_ALEN;
2967 default:
2968 return 0;
2969 }
2970}
2971
2972static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2973 unsigned long arg, int ifreq_len)
2974{
2975 struct tun_file *tfile = file->private_data;
2976 struct net *net = sock_net(&tfile->sk);
2977 struct tun_struct *tun;
2978 void __user* argp = (void __user*)arg;
2979 unsigned int ifindex, carrier;
2980 struct ifreq ifr;
2981 kuid_t owner;
2982 kgid_t group;
2983 int sndbuf;
2984 int vnet_hdr_sz;
2985 int le;
2986 int ret;
2987 bool do_notify = false;
2988
2989 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
2990 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
2991 if (copy_from_user(&ifr, argp, ifreq_len))
2992 return -EFAULT;
2993 } else {
2994 memset(&ifr, 0, sizeof(ifr));
2995 }
2996 if (cmd == TUNGETFEATURES) {
2997 /* Currently this just means: "what IFF flags are valid?".
2998 * This is needed because we never checked for invalid flags on
2999 * TUNSETIFF.
3000 */
3001 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
3002 (unsigned int __user*)argp);
3003 } else if (cmd == TUNSETQUEUE) {
3004 return tun_set_queue(file, &ifr);
3005 } else if (cmd == SIOCGSKNS) {
3006 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3007 return -EPERM;
3008 return open_related_ns(&net->ns, get_net_ns);
3009 }
3010
3011 rtnl_lock();
3012
3013 tun = tun_get(tfile);
3014 if (cmd == TUNSETIFF) {
3015 ret = -EEXIST;
3016 if (tun)
3017 goto unlock;
3018
3019 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3020
3021 ret = tun_set_iff(net, file, &ifr);
3022
3023 if (ret)
3024 goto unlock;
3025
3026 if (copy_to_user(argp, &ifr, ifreq_len))
3027 ret = -EFAULT;
3028 goto unlock;
3029 }
3030 if (cmd == TUNSETIFINDEX) {
3031 ret = -EPERM;
3032 if (tun)
3033 goto unlock;
3034
3035 ret = -EFAULT;
3036 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3037 goto unlock;
3038
3039 ret = 0;
3040 tfile->ifindex = ifindex;
3041 goto unlock;
3042 }
3043
3044 ret = -EBADFD;
3045 if (!tun)
3046 goto unlock;
3047
3048 netif_info(tun, drv, tun->dev, "tun_chr_ioctl cmd %u\n", cmd);
3049
3050 net = dev_net(tun->dev);
3051 ret = 0;
3052 switch (cmd) {
3053 case TUNGETIFF:
3054 tun_get_iff(tun, &ifr);
3055
3056 if (tfile->detached)
3057 ifr.ifr_flags |= IFF_DETACH_QUEUE;
3058 if (!tfile->socket.sk->sk_filter)
3059 ifr.ifr_flags |= IFF_NOFILTER;
3060
3061 if (copy_to_user(argp, &ifr, ifreq_len))
3062 ret = -EFAULT;
3063 break;
3064
3065 case TUNSETNOCSUM:
3066 /* Disable/Enable checksum */
3067
3068 /* [unimplemented] */
3069 netif_info(tun, drv, tun->dev, "ignored: set checksum %s\n",
3070 arg ? "disabled" : "enabled");
3071 break;
3072
3073 case TUNSETPERSIST:
3074 /* Disable/Enable persist mode. Keep an extra reference to the
3075 * module to prevent the module being unprobed.
3076 */
3077 if (arg && !(tun->flags & IFF_PERSIST)) {
3078 tun->flags |= IFF_PERSIST;
3079 __module_get(THIS_MODULE);
3080 do_notify = true;
3081 }
3082 if (!arg && (tun->flags & IFF_PERSIST)) {
3083 tun->flags &= ~IFF_PERSIST;
3084 module_put(THIS_MODULE);
3085 do_notify = true;
3086 }
3087
3088 netif_info(tun, drv, tun->dev, "persist %s\n",
3089 arg ? "enabled" : "disabled");
3090 break;
3091
3092 case TUNSETOWNER:
3093 /* Set owner of the device */
3094 owner = make_kuid(current_user_ns(), arg);
3095 if (!uid_valid(owner)) {
3096 ret = -EINVAL;
3097 break;
3098 }
3099 tun->owner = owner;
3100 do_notify = true;
3101 netif_info(tun, drv, tun->dev, "owner set to %u\n",
3102 from_kuid(&init_user_ns, tun->owner));
3103 break;
3104
3105 case TUNSETGROUP:
3106 /* Set group of the device */
3107 group = make_kgid(current_user_ns(), arg);
3108 if (!gid_valid(group)) {
3109 ret = -EINVAL;
3110 break;
3111 }
3112 tun->group = group;
3113 do_notify = true;
3114 netif_info(tun, drv, tun->dev, "group set to %u\n",
3115 from_kgid(&init_user_ns, tun->group));
3116 break;
3117
3118 case TUNSETLINK:
3119 /* Only allow setting the type when the interface is down */
3120 if (tun->dev->flags & IFF_UP) {
3121 netif_info(tun, drv, tun->dev,
3122 "Linktype set failed because interface is up\n");
3123 ret = -EBUSY;
3124 } else {
3125 ret = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE,
3126 tun->dev);
3127 ret = notifier_to_errno(ret);
3128 if (ret) {
3129 netif_info(tun, drv, tun->dev,
3130 "Refused to change device type\n");
3131 break;
3132 }
3133 tun->dev->type = (int) arg;
3134 tun->dev->addr_len = tun_get_addr_len(tun->dev->type);
3135 netif_info(tun, drv, tun->dev, "linktype set to %d\n",
3136 tun->dev->type);
3137 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE,
3138 tun->dev);
3139 }
3140 break;
3141
3142 case TUNSETDEBUG:
3143 tun->msg_enable = (u32)arg;
3144 break;
3145
3146 case TUNSETOFFLOAD:
3147 ret = set_offload(tun, arg);
3148 break;
3149
3150 case TUNSETTXFILTER:
3151 /* Can be set only for TAPs */
3152 ret = -EINVAL;
3153 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3154 break;
3155 ret = update_filter(&tun->txflt, (void __user *)arg);
3156 break;
3157
3158 case SIOCGIFHWADDR:
3159 /* Get hw address */
3160 dev_get_mac_address(&ifr.ifr_hwaddr, net, tun->dev->name);
3161 if (copy_to_user(argp, &ifr, ifreq_len))
3162 ret = -EFAULT;
3163 break;
3164
3165 case SIOCSIFHWADDR:
3166 /* Set hw address */
3167 ret = dev_set_mac_address_user(tun->dev, &ifr.ifr_hwaddr, NULL);
3168 break;
3169
3170 case TUNGETSNDBUF:
3171 sndbuf = tfile->socket.sk->sk_sndbuf;
3172 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3173 ret = -EFAULT;
3174 break;
3175
3176 case TUNSETSNDBUF:
3177 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3178 ret = -EFAULT;
3179 break;
3180 }
3181 if (sndbuf <= 0) {
3182 ret = -EINVAL;
3183 break;
3184 }
3185
3186 tun->sndbuf = sndbuf;
3187 tun_set_sndbuf(tun);
3188 break;
3189
3190 case TUNGETVNETHDRSZ:
3191 vnet_hdr_sz = tun->vnet_hdr_sz;
3192 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3193 ret = -EFAULT;
3194 break;
3195
3196 case TUNSETVNETHDRSZ:
3197 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3198 ret = -EFAULT;
3199 break;
3200 }
3201 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3202 ret = -EINVAL;
3203 break;
3204 }
3205
3206 tun->vnet_hdr_sz = vnet_hdr_sz;
3207 break;
3208
3209 case TUNGETVNETLE:
3210 le = !!(tun->flags & TUN_VNET_LE);
3211 if (put_user(le, (int __user *)argp))
3212 ret = -EFAULT;
3213 break;
3214
3215 case TUNSETVNETLE:
3216 if (get_user(le, (int __user *)argp)) {
3217 ret = -EFAULT;
3218 break;
3219 }
3220 if (le)
3221 tun->flags |= TUN_VNET_LE;
3222 else
3223 tun->flags &= ~TUN_VNET_LE;
3224 break;
3225
3226 case TUNGETVNETBE:
3227 ret = tun_get_vnet_be(tun, argp);
3228 break;
3229
3230 case TUNSETVNETBE:
3231 ret = tun_set_vnet_be(tun, argp);
3232 break;
3233
3234 case TUNATTACHFILTER:
3235 /* Can be set only for TAPs */
3236 ret = -EINVAL;
3237 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3238 break;
3239 ret = -EFAULT;
3240 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3241 break;
3242
3243 ret = tun_attach_filter(tun);
3244 break;
3245
3246 case TUNDETACHFILTER:
3247 /* Can be set only for TAPs */
3248 ret = -EINVAL;
3249 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3250 break;
3251 ret = 0;
3252 tun_detach_filter(tun, tun->numqueues);
3253 break;
3254
3255 case TUNGETFILTER:
3256 ret = -EINVAL;
3257 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3258 break;
3259 ret = -EFAULT;
3260 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3261 break;
3262 ret = 0;
3263 break;
3264
3265 case TUNSETSTEERINGEBPF:
3266 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3267 break;
3268
3269 case TUNSETFILTEREBPF:
3270 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3271 break;
3272
3273 case TUNSETCARRIER:
3274 ret = -EFAULT;
3275 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3276 goto unlock;
3277
3278 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3279 break;
3280
3281 case TUNGETDEVNETNS:
3282 ret = -EPERM;
3283 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3284 goto unlock;
3285 ret = open_related_ns(&net->ns, get_net_ns);
3286 break;
3287
3288 default:
3289 ret = -EINVAL;
3290 break;
3291 }
3292
3293 if (do_notify)
3294 netdev_state_change(tun->dev);
3295
3296unlock:
3297 rtnl_unlock();
3298 if (tun)
3299 tun_put(tun);
3300 return ret;
3301}
3302
3303static long tun_chr_ioctl(struct file *file,
3304 unsigned int cmd, unsigned long arg)
3305{
3306 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3307}
3308
3309#ifdef CONFIG_COMPAT
3310static long tun_chr_compat_ioctl(struct file *file,
3311 unsigned int cmd, unsigned long arg)
3312{
3313 switch (cmd) {
3314 case TUNSETIFF:
3315 case TUNGETIFF:
3316 case TUNSETTXFILTER:
3317 case TUNGETSNDBUF:
3318 case TUNSETSNDBUF:
3319 case SIOCGIFHWADDR:
3320 case SIOCSIFHWADDR:
3321 arg = (unsigned long)compat_ptr(arg);
3322 break;
3323 default:
3324 arg = (compat_ulong_t)arg;
3325 break;
3326 }
3327
3328 /*
3329 * compat_ifreq is shorter than ifreq, so we must not access beyond
3330 * the end of that structure. All fields that are used in this
3331 * driver are compatible though, we don't need to convert the
3332 * contents.
3333 */
3334 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3335}
3336#endif /* CONFIG_COMPAT */
3337
3338static int tun_chr_fasync(int fd, struct file *file, int on)
3339{
3340 struct tun_file *tfile = file->private_data;
3341 int ret;
3342
3343 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3344 goto out;
3345
3346 if (on) {
3347 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3348 tfile->flags |= TUN_FASYNC;
3349 } else
3350 tfile->flags &= ~TUN_FASYNC;
3351 ret = 0;
3352out:
3353 return ret;
3354}
3355
3356static int tun_chr_open(struct inode *inode, struct file * file)
3357{
3358 struct net *net = current->nsproxy->net_ns;
3359 struct tun_file *tfile;
3360
3361 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3362 &tun_proto, 0);
3363 if (!tfile)
3364 return -ENOMEM;
3365 if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3366 sk_free(&tfile->sk);
3367 return -ENOMEM;
3368 }
3369
3370 mutex_init(&tfile->napi_mutex);
3371 RCU_INIT_POINTER(tfile->tun, NULL);
3372 tfile->flags = 0;
3373 tfile->ifindex = 0;
3374
3375 init_waitqueue_head(&tfile->socket.wq.wait);
3376
3377 tfile->socket.file = file;
3378 tfile->socket.ops = &tun_socket_ops;
3379
3380 sock_init_data(&tfile->socket, &tfile->sk);
3381
3382 tfile->sk.sk_write_space = tun_sock_write_space;
3383 tfile->sk.sk_sndbuf = INT_MAX;
3384
3385 file->private_data = tfile;
3386 INIT_LIST_HEAD(&tfile->next);
3387
3388 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3389
3390 return 0;
3391}
3392
3393static int tun_chr_close(struct inode *inode, struct file *file)
3394{
3395 struct tun_file *tfile = file->private_data;
3396
3397 tun_detach(tfile, true);
3398
3399 return 0;
3400}
3401
3402#ifdef CONFIG_PROC_FS
3403static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3404{
3405 struct tun_file *tfile = file->private_data;
3406 struct tun_struct *tun;
3407 struct ifreq ifr;
3408
3409 memset(&ifr, 0, sizeof(ifr));
3410
3411 rtnl_lock();
3412 tun = tun_get(tfile);
3413 if (tun)
3414 tun_get_iff(tun, &ifr);
3415 rtnl_unlock();
3416
3417 if (tun)
3418 tun_put(tun);
3419
3420 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3421}
3422#endif
3423
3424static const struct file_operations tun_fops = {
3425 .owner = THIS_MODULE,
3426 .llseek = no_llseek,
3427 .read_iter = tun_chr_read_iter,
3428 .write_iter = tun_chr_write_iter,
3429 .poll = tun_chr_poll,
3430 .unlocked_ioctl = tun_chr_ioctl,
3431#ifdef CONFIG_COMPAT
3432 .compat_ioctl = tun_chr_compat_ioctl,
3433#endif
3434 .open = tun_chr_open,
3435 .release = tun_chr_close,
3436 .fasync = tun_chr_fasync,
3437#ifdef CONFIG_PROC_FS
3438 .show_fdinfo = tun_chr_show_fdinfo,
3439#endif
3440};
3441
3442static struct miscdevice tun_miscdev = {
3443 .minor = TUN_MINOR,
3444 .name = "tun",
3445 .nodename = "net/tun",
3446 .fops = &tun_fops,
3447};
3448
3449/* ethtool interface */
3450
3451static void tun_default_link_ksettings(struct net_device *dev,
3452 struct ethtool_link_ksettings *cmd)
3453{
3454 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3455 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3456 cmd->base.speed = SPEED_10;
3457 cmd->base.duplex = DUPLEX_FULL;
3458 cmd->base.port = PORT_TP;
3459 cmd->base.phy_address = 0;
3460 cmd->base.autoneg = AUTONEG_DISABLE;
3461}
3462
3463static int tun_get_link_ksettings(struct net_device *dev,
3464 struct ethtool_link_ksettings *cmd)
3465{
3466 struct tun_struct *tun = netdev_priv(dev);
3467
3468 memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3469 return 0;
3470}
3471
3472static int tun_set_link_ksettings(struct net_device *dev,
3473 const struct ethtool_link_ksettings *cmd)
3474{
3475 struct tun_struct *tun = netdev_priv(dev);
3476
3477 memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3478 return 0;
3479}
3480
3481static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3482{
3483 struct tun_struct *tun = netdev_priv(dev);
3484
3485 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3486 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3487
3488 switch (tun->flags & TUN_TYPE_MASK) {
3489 case IFF_TUN:
3490 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3491 break;
3492 case IFF_TAP:
3493 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3494 break;
3495 }
3496}
3497
3498static u32 tun_get_msglevel(struct net_device *dev)
3499{
3500 struct tun_struct *tun = netdev_priv(dev);
3501
3502 return tun->msg_enable;
3503}
3504
3505static void tun_set_msglevel(struct net_device *dev, u32 value)
3506{
3507 struct tun_struct *tun = netdev_priv(dev);
3508
3509 tun->msg_enable = value;
3510}
3511
3512static int tun_get_coalesce(struct net_device *dev,
3513 struct ethtool_coalesce *ec)
3514{
3515 struct tun_struct *tun = netdev_priv(dev);
3516
3517 ec->rx_max_coalesced_frames = tun->rx_batched;
3518
3519 return 0;
3520}
3521
3522static int tun_set_coalesce(struct net_device *dev,
3523 struct ethtool_coalesce *ec)
3524{
3525 struct tun_struct *tun = netdev_priv(dev);
3526
3527 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3528 tun->rx_batched = NAPI_POLL_WEIGHT;
3529 else
3530 tun->rx_batched = ec->rx_max_coalesced_frames;
3531
3532 return 0;
3533}
3534
3535static const struct ethtool_ops tun_ethtool_ops = {
3536 .supported_coalesce_params = ETHTOOL_COALESCE_RX_MAX_FRAMES,
3537 .get_drvinfo = tun_get_drvinfo,
3538 .get_msglevel = tun_get_msglevel,
3539 .set_msglevel = tun_set_msglevel,
3540 .get_link = ethtool_op_get_link,
3541 .get_ts_info = ethtool_op_get_ts_info,
3542 .get_coalesce = tun_get_coalesce,
3543 .set_coalesce = tun_set_coalesce,
3544 .get_link_ksettings = tun_get_link_ksettings,
3545 .set_link_ksettings = tun_set_link_ksettings,
3546};
3547
3548static int tun_queue_resize(struct tun_struct *tun)
3549{
3550 struct net_device *dev = tun->dev;
3551 struct tun_file *tfile;
3552 struct ptr_ring **rings;
3553 int n = tun->numqueues + tun->numdisabled;
3554 int ret, i;
3555
3556 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3557 if (!rings)
3558 return -ENOMEM;
3559
3560 for (i = 0; i < tun->numqueues; i++) {
3561 tfile = rtnl_dereference(tun->tfiles[i]);
3562 rings[i] = &tfile->tx_ring;
3563 }
3564 list_for_each_entry(tfile, &tun->disabled, next)
3565 rings[i++] = &tfile->tx_ring;
3566
3567 ret = ptr_ring_resize_multiple(rings, n,
3568 dev->tx_queue_len, GFP_KERNEL,
3569 tun_ptr_free);
3570
3571 kfree(rings);
3572 return ret;
3573}
3574
3575static int tun_device_event(struct notifier_block *unused,
3576 unsigned long event, void *ptr)
3577{
3578 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3579 struct tun_struct *tun = netdev_priv(dev);
3580 int i;
3581
3582 if (dev->rtnl_link_ops != &tun_link_ops)
3583 return NOTIFY_DONE;
3584
3585 switch (event) {
3586 case NETDEV_CHANGE_TX_QUEUE_LEN:
3587 if (tun_queue_resize(tun))
3588 return NOTIFY_BAD;
3589 break;
3590 case NETDEV_UP:
3591 for (i = 0; i < tun->numqueues; i++) {
3592 struct tun_file *tfile;
3593
3594 tfile = rtnl_dereference(tun->tfiles[i]);
3595 tfile->socket.sk->sk_write_space(tfile->socket.sk);
3596 }
3597 break;
3598 default:
3599 break;
3600 }
3601
3602 return NOTIFY_DONE;
3603}
3604
3605static struct notifier_block tun_notifier_block __read_mostly = {
3606 .notifier_call = tun_device_event,
3607};
3608
3609static int __init tun_init(void)
3610{
3611 int ret = 0;
3612
3613 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3614
3615 ret = rtnl_link_register(&tun_link_ops);
3616 if (ret) {
3617 pr_err("Can't register link_ops\n");
3618 goto err_linkops;
3619 }
3620
3621 ret = misc_register(&tun_miscdev);
3622 if (ret) {
3623 pr_err("Can't register misc device %d\n", TUN_MINOR);
3624 goto err_misc;
3625 }
3626
3627 ret = register_netdevice_notifier(&tun_notifier_block);
3628 if (ret) {
3629 pr_err("Can't register netdevice notifier\n");
3630 goto err_notifier;
3631 }
3632
3633 return 0;
3634
3635err_notifier:
3636 misc_deregister(&tun_miscdev);
3637err_misc:
3638 rtnl_link_unregister(&tun_link_ops);
3639err_linkops:
3640 return ret;
3641}
3642
3643static void tun_cleanup(void)
3644{
3645 misc_deregister(&tun_miscdev);
3646 rtnl_link_unregister(&tun_link_ops);
3647 unregister_netdevice_notifier(&tun_notifier_block);
3648}
3649
3650/* Get an underlying socket object from tun file. Returns error unless file is
3651 * attached to a device. The returned object works like a packet socket, it
3652 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3653 * holding a reference to the file for as long as the socket is in use. */
3654struct socket *tun_get_socket(struct file *file)
3655{
3656 struct tun_file *tfile;
3657 if (file->f_op != &tun_fops)
3658 return ERR_PTR(-EINVAL);
3659 tfile = file->private_data;
3660 if (!tfile)
3661 return ERR_PTR(-EBADFD);
3662 return &tfile->socket;
3663}
3664EXPORT_SYMBOL_GPL(tun_get_socket);
3665
3666struct ptr_ring *tun_get_tx_ring(struct file *file)
3667{
3668 struct tun_file *tfile;
3669
3670 if (file->f_op != &tun_fops)
3671 return ERR_PTR(-EINVAL);
3672 tfile = file->private_data;
3673 if (!tfile)
3674 return ERR_PTR(-EBADFD);
3675 return &tfile->tx_ring;
3676}
3677EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3678
3679module_init(tun_init);
3680module_exit(tun_cleanup);
3681MODULE_DESCRIPTION(DRV_DESCRIPTION);
3682MODULE_AUTHOR(DRV_COPYRIGHT);
3683MODULE_LICENSE("GPL");
3684MODULE_ALIAS_MISCDEV(TUN_MINOR);
3685MODULE_ALIAS("devname:net/tun");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * TUN - Universal TUN/TAP device driver.
4 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
5 *
6 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
7 */
8
9/*
10 * Changes:
11 *
12 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
13 * Add TUNSETLINK ioctl to set the link encapsulation
14 *
15 * Mark Smith <markzzzsmith@yahoo.com.au>
16 * Use eth_random_addr() for tap MAC address.
17 *
18 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
19 * Fixes in packet dropping, queue length setting and queue wakeup.
20 * Increased default tx queue length.
21 * Added ethtool API.
22 * Minor cleanups
23 *
24 * Daniel Podlejski <underley@underley.eu.org>
25 * Modifications for 2.3.99-pre5 kernel.
26 */
27
28#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29
30#define DRV_NAME "tun"
31#define DRV_VERSION "1.6"
32#define DRV_DESCRIPTION "Universal TUN/TAP device driver"
33#define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
34
35#include <linux/module.h>
36#include <linux/errno.h>
37#include <linux/kernel.h>
38#include <linux/sched/signal.h>
39#include <linux/major.h>
40#include <linux/slab.h>
41#include <linux/poll.h>
42#include <linux/fcntl.h>
43#include <linux/init.h>
44#include <linux/skbuff.h>
45#include <linux/netdevice.h>
46#include <linux/etherdevice.h>
47#include <linux/miscdevice.h>
48#include <linux/ethtool.h>
49#include <linux/rtnetlink.h>
50#include <linux/compat.h>
51#include <linux/if.h>
52#include <linux/if_arp.h>
53#include <linux/if_ether.h>
54#include <linux/if_tun.h>
55#include <linux/if_vlan.h>
56#include <linux/crc32.h>
57#include <linux/nsproxy.h>
58#include <linux/virtio_net.h>
59#include <linux/rcupdate.h>
60#include <net/net_namespace.h>
61#include <net/netns/generic.h>
62#include <net/rtnetlink.h>
63#include <net/sock.h>
64#include <net/xdp.h>
65#include <net/ip_tunnels.h>
66#include <linux/seq_file.h>
67#include <linux/uio.h>
68#include <linux/skb_array.h>
69#include <linux/bpf.h>
70#include <linux/bpf_trace.h>
71#include <linux/mutex.h>
72#include <linux/ieee802154.h>
73#include <linux/if_ltalk.h>
74#include <uapi/linux/if_fddi.h>
75#include <uapi/linux/if_hippi.h>
76#include <uapi/linux/if_fc.h>
77#include <net/ax25.h>
78#include <net/rose.h>
79#include <net/6lowpan.h>
80
81#include <linux/uaccess.h>
82#include <linux/proc_fs.h>
83
84static void tun_default_link_ksettings(struct net_device *dev,
85 struct ethtool_link_ksettings *cmd);
86
87#define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
88
89/* TUN device flags */
90
91/* IFF_ATTACH_QUEUE is never stored in device flags,
92 * overload it to mean fasync when stored there.
93 */
94#define TUN_FASYNC IFF_ATTACH_QUEUE
95/* High bits in flags field are unused. */
96#define TUN_VNET_LE 0x80000000
97#define TUN_VNET_BE 0x40000000
98
99#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
100 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
101
102#define GOODCOPY_LEN 128
103
104#define FLT_EXACT_COUNT 8
105struct tap_filter {
106 unsigned int count; /* Number of addrs. Zero means disabled */
107 u32 mask[2]; /* Mask of the hashed addrs */
108 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
109};
110
111/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
112 * to max number of VCPUs in guest. */
113#define MAX_TAP_QUEUES 256
114#define MAX_TAP_FLOWS 4096
115
116#define TUN_FLOW_EXPIRE (3 * HZ)
117
118/* A tun_file connects an open character device to a tuntap netdevice. It
119 * also contains all socket related structures (except sock_fprog and tap_filter)
120 * to serve as one transmit queue for tuntap device. The sock_fprog and
121 * tap_filter were kept in tun_struct since they were used for filtering for the
122 * netdevice not for a specific queue (at least I didn't see the requirement for
123 * this).
124 *
125 * RCU usage:
126 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
127 * other can only be read while rcu_read_lock or rtnl_lock is held.
128 */
129struct tun_file {
130 struct sock sk;
131 struct socket socket;
132 struct tun_struct __rcu *tun;
133 struct fasync_struct *fasync;
134 /* only used for fasnyc */
135 unsigned int flags;
136 union {
137 u16 queue_index;
138 unsigned int ifindex;
139 };
140 struct napi_struct napi;
141 bool napi_enabled;
142 bool napi_frags_enabled;
143 struct mutex napi_mutex; /* Protects access to the above napi */
144 struct list_head next;
145 struct tun_struct *detached;
146 struct ptr_ring tx_ring;
147 struct xdp_rxq_info xdp_rxq;
148};
149
150struct tun_page {
151 struct page *page;
152 int count;
153};
154
155struct tun_flow_entry {
156 struct hlist_node hash_link;
157 struct rcu_head rcu;
158 struct tun_struct *tun;
159
160 u32 rxhash;
161 u32 rps_rxhash;
162 int queue_index;
163 unsigned long updated ____cacheline_aligned_in_smp;
164};
165
166#define TUN_NUM_FLOW_ENTRIES 1024
167#define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
168
169struct tun_prog {
170 struct rcu_head rcu;
171 struct bpf_prog *prog;
172};
173
174/* Since the socket were moved to tun_file, to preserve the behavior of persist
175 * device, socket filter, sndbuf and vnet header size were restore when the
176 * file were attached to a persist device.
177 */
178struct tun_struct {
179 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
180 unsigned int numqueues;
181 unsigned int flags;
182 kuid_t owner;
183 kgid_t group;
184
185 struct net_device *dev;
186 netdev_features_t set_features;
187#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
188 NETIF_F_TSO6 | NETIF_F_GSO_UDP_L4)
189
190 int align;
191 int vnet_hdr_sz;
192 int sndbuf;
193 struct tap_filter txflt;
194 struct sock_fprog fprog;
195 /* protected by rtnl lock */
196 bool filter_attached;
197 u32 msg_enable;
198 spinlock_t lock;
199 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
200 struct timer_list flow_gc_timer;
201 unsigned long ageing_time;
202 unsigned int numdisabled;
203 struct list_head disabled;
204 void *security;
205 u32 flow_count;
206 u32 rx_batched;
207 atomic_long_t rx_frame_errors;
208 struct bpf_prog __rcu *xdp_prog;
209 struct tun_prog __rcu *steering_prog;
210 struct tun_prog __rcu *filter_prog;
211 struct ethtool_link_ksettings link_ksettings;
212 /* init args */
213 struct file *file;
214 struct ifreq *ifr;
215};
216
217struct veth {
218 __be16 h_vlan_proto;
219 __be16 h_vlan_TCI;
220};
221
222static void tun_flow_init(struct tun_struct *tun);
223static void tun_flow_uninit(struct tun_struct *tun);
224
225static int tun_napi_receive(struct napi_struct *napi, int budget)
226{
227 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
228 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
229 struct sk_buff_head process_queue;
230 struct sk_buff *skb;
231 int received = 0;
232
233 __skb_queue_head_init(&process_queue);
234
235 spin_lock(&queue->lock);
236 skb_queue_splice_tail_init(queue, &process_queue);
237 spin_unlock(&queue->lock);
238
239 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
240 napi_gro_receive(napi, skb);
241 ++received;
242 }
243
244 if (!skb_queue_empty(&process_queue)) {
245 spin_lock(&queue->lock);
246 skb_queue_splice(&process_queue, queue);
247 spin_unlock(&queue->lock);
248 }
249
250 return received;
251}
252
253static int tun_napi_poll(struct napi_struct *napi, int budget)
254{
255 unsigned int received;
256
257 received = tun_napi_receive(napi, budget);
258
259 if (received < budget)
260 napi_complete_done(napi, received);
261
262 return received;
263}
264
265static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
266 bool napi_en, bool napi_frags)
267{
268 tfile->napi_enabled = napi_en;
269 tfile->napi_frags_enabled = napi_en && napi_frags;
270 if (napi_en) {
271 netif_napi_add_tx(tun->dev, &tfile->napi, tun_napi_poll);
272 napi_enable(&tfile->napi);
273 }
274}
275
276static void tun_napi_enable(struct tun_file *tfile)
277{
278 if (tfile->napi_enabled)
279 napi_enable(&tfile->napi);
280}
281
282static void tun_napi_disable(struct tun_file *tfile)
283{
284 if (tfile->napi_enabled)
285 napi_disable(&tfile->napi);
286}
287
288static void tun_napi_del(struct tun_file *tfile)
289{
290 if (tfile->napi_enabled)
291 netif_napi_del(&tfile->napi);
292}
293
294static bool tun_napi_frags_enabled(const struct tun_file *tfile)
295{
296 return tfile->napi_frags_enabled;
297}
298
299#ifdef CONFIG_TUN_VNET_CROSS_LE
300static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
301{
302 return tun->flags & TUN_VNET_BE ? false :
303 virtio_legacy_is_little_endian();
304}
305
306static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
307{
308 int be = !!(tun->flags & TUN_VNET_BE);
309
310 if (put_user(be, argp))
311 return -EFAULT;
312
313 return 0;
314}
315
316static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
317{
318 int be;
319
320 if (get_user(be, argp))
321 return -EFAULT;
322
323 if (be)
324 tun->flags |= TUN_VNET_BE;
325 else
326 tun->flags &= ~TUN_VNET_BE;
327
328 return 0;
329}
330#else
331static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
332{
333 return virtio_legacy_is_little_endian();
334}
335
336static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
337{
338 return -EINVAL;
339}
340
341static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
342{
343 return -EINVAL;
344}
345#endif /* CONFIG_TUN_VNET_CROSS_LE */
346
347static inline bool tun_is_little_endian(struct tun_struct *tun)
348{
349 return tun->flags & TUN_VNET_LE ||
350 tun_legacy_is_little_endian(tun);
351}
352
353static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
354{
355 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
356}
357
358static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
359{
360 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
361}
362
363static inline u32 tun_hashfn(u32 rxhash)
364{
365 return rxhash & TUN_MASK_FLOW_ENTRIES;
366}
367
368static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
369{
370 struct tun_flow_entry *e;
371
372 hlist_for_each_entry_rcu(e, head, hash_link) {
373 if (e->rxhash == rxhash)
374 return e;
375 }
376 return NULL;
377}
378
379static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
380 struct hlist_head *head,
381 u32 rxhash, u16 queue_index)
382{
383 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
384
385 if (e) {
386 netif_info(tun, tx_queued, tun->dev,
387 "create flow: hash %u index %u\n",
388 rxhash, queue_index);
389 e->updated = jiffies;
390 e->rxhash = rxhash;
391 e->rps_rxhash = 0;
392 e->queue_index = queue_index;
393 e->tun = tun;
394 hlist_add_head_rcu(&e->hash_link, head);
395 ++tun->flow_count;
396 }
397 return e;
398}
399
400static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
401{
402 netif_info(tun, tx_queued, tun->dev, "delete flow: hash %u index %u\n",
403 e->rxhash, e->queue_index);
404 hlist_del_rcu(&e->hash_link);
405 kfree_rcu(e, rcu);
406 --tun->flow_count;
407}
408
409static void tun_flow_flush(struct tun_struct *tun)
410{
411 int i;
412
413 spin_lock_bh(&tun->lock);
414 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
415 struct tun_flow_entry *e;
416 struct hlist_node *n;
417
418 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
419 tun_flow_delete(tun, e);
420 }
421 spin_unlock_bh(&tun->lock);
422}
423
424static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
425{
426 int i;
427
428 spin_lock_bh(&tun->lock);
429 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
430 struct tun_flow_entry *e;
431 struct hlist_node *n;
432
433 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
434 if (e->queue_index == queue_index)
435 tun_flow_delete(tun, e);
436 }
437 }
438 spin_unlock_bh(&tun->lock);
439}
440
441static void tun_flow_cleanup(struct timer_list *t)
442{
443 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
444 unsigned long delay = tun->ageing_time;
445 unsigned long next_timer = jiffies + delay;
446 unsigned long count = 0;
447 int i;
448
449 spin_lock(&tun->lock);
450 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
451 struct tun_flow_entry *e;
452 struct hlist_node *n;
453
454 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
455 unsigned long this_timer;
456
457 this_timer = e->updated + delay;
458 if (time_before_eq(this_timer, jiffies)) {
459 tun_flow_delete(tun, e);
460 continue;
461 }
462 count++;
463 if (time_before(this_timer, next_timer))
464 next_timer = this_timer;
465 }
466 }
467
468 if (count)
469 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
470 spin_unlock(&tun->lock);
471}
472
473static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
474 struct tun_file *tfile)
475{
476 struct hlist_head *head;
477 struct tun_flow_entry *e;
478 unsigned long delay = tun->ageing_time;
479 u16 queue_index = tfile->queue_index;
480
481 head = &tun->flows[tun_hashfn(rxhash)];
482
483 rcu_read_lock();
484
485 e = tun_flow_find(head, rxhash);
486 if (likely(e)) {
487 /* TODO: keep queueing to old queue until it's empty? */
488 if (READ_ONCE(e->queue_index) != queue_index)
489 WRITE_ONCE(e->queue_index, queue_index);
490 if (e->updated != jiffies)
491 e->updated = jiffies;
492 sock_rps_record_flow_hash(e->rps_rxhash);
493 } else {
494 spin_lock_bh(&tun->lock);
495 if (!tun_flow_find(head, rxhash) &&
496 tun->flow_count < MAX_TAP_FLOWS)
497 tun_flow_create(tun, head, rxhash, queue_index);
498
499 if (!timer_pending(&tun->flow_gc_timer))
500 mod_timer(&tun->flow_gc_timer,
501 round_jiffies_up(jiffies + delay));
502 spin_unlock_bh(&tun->lock);
503 }
504
505 rcu_read_unlock();
506}
507
508/* Save the hash received in the stack receive path and update the
509 * flow_hash table accordingly.
510 */
511static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
512{
513 if (unlikely(e->rps_rxhash != hash))
514 e->rps_rxhash = hash;
515}
516
517/* We try to identify a flow through its rxhash. The reason that
518 * we do not check rxq no. is because some cards(e.g 82599), chooses
519 * the rxq based on the txq where the last packet of the flow comes. As
520 * the userspace application move between processors, we may get a
521 * different rxq no. here.
522 */
523static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
524{
525 struct tun_flow_entry *e;
526 u32 txq = 0;
527 u32 numqueues = 0;
528
529 numqueues = READ_ONCE(tun->numqueues);
530
531 txq = __skb_get_hash_symmetric(skb);
532 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
533 if (e) {
534 tun_flow_save_rps_rxhash(e, txq);
535 txq = e->queue_index;
536 } else {
537 /* use multiply and shift instead of expensive divide */
538 txq = ((u64)txq * numqueues) >> 32;
539 }
540
541 return txq;
542}
543
544static 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
561static 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
577static 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
587static 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
593static 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
600static 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
610void 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}
622EXPORT_SYMBOL_GPL(tun_ptr_free);
623
624static 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
635static 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 rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
657 NULL);
658
659 --tun->numqueues;
660 if (clean) {
661 RCU_INIT_POINTER(tfile->tun, NULL);
662 sock_put(&tfile->sk);
663 } else {
664 tun_disable_queue(tun, tfile);
665 tun_napi_disable(tfile);
666 }
667
668 synchronize_net();
669 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
670 /* Drop read queue */
671 tun_queue_purge(tfile);
672 tun_set_real_num_queues(tun);
673 } else if (tfile->detached && clean) {
674 tun = tun_enable_queue(tfile);
675 sock_put(&tfile->sk);
676 }
677
678 if (clean) {
679 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
680 netif_carrier_off(tun->dev);
681
682 if (!(tun->flags & IFF_PERSIST) &&
683 tun->dev->reg_state == NETREG_REGISTERED)
684 unregister_netdevice(tun->dev);
685 }
686 if (tun)
687 xdp_rxq_info_unreg(&tfile->xdp_rxq);
688 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
689 }
690}
691
692static void tun_detach(struct tun_file *tfile, bool clean)
693{
694 struct tun_struct *tun;
695 struct net_device *dev;
696
697 rtnl_lock();
698 tun = rtnl_dereference(tfile->tun);
699 dev = tun ? tun->dev : NULL;
700 __tun_detach(tfile, clean);
701 if (dev)
702 netdev_state_change(dev);
703 rtnl_unlock();
704
705 if (clean)
706 sock_put(&tfile->sk);
707}
708
709static void tun_detach_all(struct net_device *dev)
710{
711 struct tun_struct *tun = netdev_priv(dev);
712 struct tun_file *tfile, *tmp;
713 int i, n = tun->numqueues;
714
715 for (i = 0; i < n; i++) {
716 tfile = rtnl_dereference(tun->tfiles[i]);
717 BUG_ON(!tfile);
718 tun_napi_disable(tfile);
719 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
720 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
721 RCU_INIT_POINTER(tfile->tun, NULL);
722 --tun->numqueues;
723 }
724 list_for_each_entry(tfile, &tun->disabled, next) {
725 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
726 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
727 RCU_INIT_POINTER(tfile->tun, NULL);
728 }
729 BUG_ON(tun->numqueues != 0);
730
731 synchronize_net();
732 for (i = 0; i < n; i++) {
733 tfile = rtnl_dereference(tun->tfiles[i]);
734 tun_napi_del(tfile);
735 /* Drop read queue */
736 tun_queue_purge(tfile);
737 xdp_rxq_info_unreg(&tfile->xdp_rxq);
738 sock_put(&tfile->sk);
739 }
740 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
741 tun_napi_del(tfile);
742 tun_enable_queue(tfile);
743 tun_queue_purge(tfile);
744 xdp_rxq_info_unreg(&tfile->xdp_rxq);
745 sock_put(&tfile->sk);
746 }
747 BUG_ON(tun->numdisabled != 0);
748
749 if (tun->flags & IFF_PERSIST)
750 module_put(THIS_MODULE);
751}
752
753static int tun_attach(struct tun_struct *tun, struct file *file,
754 bool skip_filter, bool napi, bool napi_frags,
755 bool publish_tun)
756{
757 struct tun_file *tfile = file->private_data;
758 struct net_device *dev = tun->dev;
759 int err;
760
761 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
762 if (err < 0)
763 goto out;
764
765 err = -EINVAL;
766 if (rtnl_dereference(tfile->tun) && !tfile->detached)
767 goto out;
768
769 err = -EBUSY;
770 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
771 goto out;
772
773 err = -E2BIG;
774 if (!tfile->detached &&
775 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
776 goto out;
777
778 err = 0;
779
780 /* Re-attach the filter to persist device */
781 if (!skip_filter && (tun->filter_attached == true)) {
782 lock_sock(tfile->socket.sk);
783 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
784 release_sock(tfile->socket.sk);
785 if (!err)
786 goto out;
787 }
788
789 if (!tfile->detached &&
790 ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
791 GFP_KERNEL, tun_ptr_free)) {
792 err = -ENOMEM;
793 goto out;
794 }
795
796 tfile->queue_index = tun->numqueues;
797 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
798
799 if (tfile->detached) {
800 /* Re-attach detached tfile, updating XDP queue_index */
801 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
802
803 if (tfile->xdp_rxq.queue_index != tfile->queue_index)
804 tfile->xdp_rxq.queue_index = tfile->queue_index;
805 } else {
806 /* Setup XDP RX-queue info, for new tfile getting attached */
807 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
808 tun->dev, tfile->queue_index, 0);
809 if (err < 0)
810 goto out;
811 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
812 MEM_TYPE_PAGE_SHARED, NULL);
813 if (err < 0) {
814 xdp_rxq_info_unreg(&tfile->xdp_rxq);
815 goto out;
816 }
817 err = 0;
818 }
819
820 if (tfile->detached) {
821 tun_enable_queue(tfile);
822 tun_napi_enable(tfile);
823 } else {
824 sock_hold(&tfile->sk);
825 tun_napi_init(tun, tfile, napi, napi_frags);
826 }
827
828 if (rtnl_dereference(tun->xdp_prog))
829 sock_set_flag(&tfile->sk, SOCK_XDP);
830
831 /* device is allowed to go away first, so no need to hold extra
832 * refcnt.
833 */
834
835 /* Publish tfile->tun and tun->tfiles only after we've fully
836 * initialized tfile; otherwise we risk using half-initialized
837 * object.
838 */
839 if (publish_tun)
840 rcu_assign_pointer(tfile->tun, tun);
841 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
842 tun->numqueues++;
843 tun_set_real_num_queues(tun);
844out:
845 return err;
846}
847
848static struct tun_struct *tun_get(struct tun_file *tfile)
849{
850 struct tun_struct *tun;
851
852 rcu_read_lock();
853 tun = rcu_dereference(tfile->tun);
854 if (tun)
855 dev_hold(tun->dev);
856 rcu_read_unlock();
857
858 return tun;
859}
860
861static void tun_put(struct tun_struct *tun)
862{
863 dev_put(tun->dev);
864}
865
866/* TAP filtering */
867static void addr_hash_set(u32 *mask, const u8 *addr)
868{
869 int n = ether_crc(ETH_ALEN, addr) >> 26;
870 mask[n >> 5] |= (1 << (n & 31));
871}
872
873static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
874{
875 int n = ether_crc(ETH_ALEN, addr) >> 26;
876 return mask[n >> 5] & (1 << (n & 31));
877}
878
879static int update_filter(struct tap_filter *filter, void __user *arg)
880{
881 struct { u8 u[ETH_ALEN]; } *addr;
882 struct tun_filter uf;
883 int err, alen, n, nexact;
884
885 if (copy_from_user(&uf, arg, sizeof(uf)))
886 return -EFAULT;
887
888 if (!uf.count) {
889 /* Disabled */
890 filter->count = 0;
891 return 0;
892 }
893
894 alen = ETH_ALEN * uf.count;
895 addr = memdup_user(arg + sizeof(uf), alen);
896 if (IS_ERR(addr))
897 return PTR_ERR(addr);
898
899 /* The filter is updated without holding any locks. Which is
900 * perfectly safe. We disable it first and in the worst
901 * case we'll accept a few undesired packets. */
902 filter->count = 0;
903 wmb();
904
905 /* Use first set of addresses as an exact filter */
906 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
907 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
908
909 nexact = n;
910
911 /* Remaining multicast addresses are hashed,
912 * unicast will leave the filter disabled. */
913 memset(filter->mask, 0, sizeof(filter->mask));
914 for (; n < uf.count; n++) {
915 if (!is_multicast_ether_addr(addr[n].u)) {
916 err = 0; /* no filter */
917 goto free_addr;
918 }
919 addr_hash_set(filter->mask, addr[n].u);
920 }
921
922 /* For ALLMULTI just set the mask to all ones.
923 * This overrides the mask populated above. */
924 if ((uf.flags & TUN_FLT_ALLMULTI))
925 memset(filter->mask, ~0, sizeof(filter->mask));
926
927 /* Now enable the filter */
928 wmb();
929 filter->count = nexact;
930
931 /* Return the number of exact filters */
932 err = nexact;
933free_addr:
934 kfree(addr);
935 return err;
936}
937
938/* Returns: 0 - drop, !=0 - accept */
939static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
940{
941 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
942 * at this point. */
943 struct ethhdr *eh = (struct ethhdr *) skb->data;
944 int i;
945
946 /* Exact match */
947 for (i = 0; i < filter->count; i++)
948 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
949 return 1;
950
951 /* Inexact match (multicast only) */
952 if (is_multicast_ether_addr(eh->h_dest))
953 return addr_hash_test(filter->mask, eh->h_dest);
954
955 return 0;
956}
957
958/*
959 * Checks whether the packet is accepted or not.
960 * Returns: 0 - drop, !=0 - accept
961 */
962static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
963{
964 if (!filter->count)
965 return 1;
966
967 return run_filter(filter, skb);
968}
969
970/* Network device part of the driver */
971
972static const struct ethtool_ops tun_ethtool_ops;
973
974static int tun_net_init(struct net_device *dev)
975{
976 struct tun_struct *tun = netdev_priv(dev);
977 struct ifreq *ifr = tun->ifr;
978 int err;
979
980 dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
981 if (!dev->tstats)
982 return -ENOMEM;
983
984 spin_lock_init(&tun->lock);
985
986 err = security_tun_dev_alloc_security(&tun->security);
987 if (err < 0) {
988 free_percpu(dev->tstats);
989 return err;
990 }
991
992 tun_flow_init(tun);
993
994 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
995 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
996 NETIF_F_HW_VLAN_STAG_TX;
997 dev->features = dev->hw_features | NETIF_F_LLTX;
998 dev->vlan_features = dev->features &
999 ~(NETIF_F_HW_VLAN_CTAG_TX |
1000 NETIF_F_HW_VLAN_STAG_TX);
1001
1002 tun->flags = (tun->flags & ~TUN_FEATURES) |
1003 (ifr->ifr_flags & TUN_FEATURES);
1004
1005 INIT_LIST_HEAD(&tun->disabled);
1006 err = tun_attach(tun, tun->file, false, ifr->ifr_flags & IFF_NAPI,
1007 ifr->ifr_flags & IFF_NAPI_FRAGS, false);
1008 if (err < 0) {
1009 tun_flow_uninit(tun);
1010 security_tun_dev_free_security(tun->security);
1011 free_percpu(dev->tstats);
1012 return err;
1013 }
1014 return 0;
1015}
1016
1017/* Net device detach from fd. */
1018static void tun_net_uninit(struct net_device *dev)
1019{
1020 tun_detach_all(dev);
1021}
1022
1023/* Net device open. */
1024static int tun_net_open(struct net_device *dev)
1025{
1026 netif_tx_start_all_queues(dev);
1027
1028 return 0;
1029}
1030
1031/* Net device close. */
1032static int tun_net_close(struct net_device *dev)
1033{
1034 netif_tx_stop_all_queues(dev);
1035 return 0;
1036}
1037
1038/* Net device start xmit */
1039static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1040{
1041#ifdef CONFIG_RPS
1042 if (tun->numqueues == 1 && static_branch_unlikely(&rps_needed)) {
1043 /* Select queue was not called for the skbuff, so we extract the
1044 * RPS hash and save it into the flow_table here.
1045 */
1046 struct tun_flow_entry *e;
1047 __u32 rxhash;
1048
1049 rxhash = __skb_get_hash_symmetric(skb);
1050 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
1051 if (e)
1052 tun_flow_save_rps_rxhash(e, rxhash);
1053 }
1054#endif
1055}
1056
1057static unsigned int run_ebpf_filter(struct tun_struct *tun,
1058 struct sk_buff *skb,
1059 int len)
1060{
1061 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1062
1063 if (prog)
1064 len = bpf_prog_run_clear_cb(prog->prog, skb);
1065
1066 return len;
1067}
1068
1069/* Net device start xmit */
1070static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1071{
1072 struct tun_struct *tun = netdev_priv(dev);
1073 enum skb_drop_reason drop_reason;
1074 int txq = skb->queue_mapping;
1075 struct netdev_queue *queue;
1076 struct tun_file *tfile;
1077 int len = skb->len;
1078
1079 rcu_read_lock();
1080 tfile = rcu_dereference(tun->tfiles[txq]);
1081
1082 /* Drop packet if interface is not attached */
1083 if (!tfile) {
1084 drop_reason = SKB_DROP_REASON_DEV_READY;
1085 goto drop;
1086 }
1087
1088 if (!rcu_dereference(tun->steering_prog))
1089 tun_automq_xmit(tun, skb);
1090
1091 netif_info(tun, tx_queued, tun->dev, "%s %d\n", __func__, skb->len);
1092
1093 /* Drop if the filter does not like it.
1094 * This is a noop if the filter is disabled.
1095 * Filter can be enabled only for the TAP devices. */
1096 if (!check_filter(&tun->txflt, skb)) {
1097 drop_reason = SKB_DROP_REASON_TAP_TXFILTER;
1098 goto drop;
1099 }
1100
1101 if (tfile->socket.sk->sk_filter &&
1102 sk_filter(tfile->socket.sk, skb)) {
1103 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
1104 goto drop;
1105 }
1106
1107 len = run_ebpf_filter(tun, skb, len);
1108 if (len == 0) {
1109 drop_reason = SKB_DROP_REASON_TAP_FILTER;
1110 goto drop;
1111 }
1112
1113 if (pskb_trim(skb, len)) {
1114 drop_reason = SKB_DROP_REASON_NOMEM;
1115 goto drop;
1116 }
1117
1118 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) {
1119 drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
1120 goto drop;
1121 }
1122
1123 skb_tx_timestamp(skb);
1124
1125 /* Orphan the skb - required as we might hang on to it
1126 * for indefinite time.
1127 */
1128 skb_orphan(skb);
1129
1130 nf_reset_ct(skb);
1131
1132 if (ptr_ring_produce(&tfile->tx_ring, skb)) {
1133 drop_reason = SKB_DROP_REASON_FULL_RING;
1134 goto drop;
1135 }
1136
1137 /* NETIF_F_LLTX requires to do our own update of trans_start */
1138 queue = netdev_get_tx_queue(dev, txq);
1139 txq_trans_cond_update(queue);
1140
1141 /* Notify and wake up reader process */
1142 if (tfile->flags & TUN_FASYNC)
1143 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1144 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1145
1146 rcu_read_unlock();
1147 return NETDEV_TX_OK;
1148
1149drop:
1150 dev_core_stats_tx_dropped_inc(dev);
1151 skb_tx_error(skb);
1152 kfree_skb_reason(skb, drop_reason);
1153 rcu_read_unlock();
1154 return NET_XMIT_DROP;
1155}
1156
1157static void tun_net_mclist(struct net_device *dev)
1158{
1159 /*
1160 * This callback is supposed to deal with mc filter in
1161 * _rx_ path and has nothing to do with the _tx_ path.
1162 * In rx path we always accept everything userspace gives us.
1163 */
1164}
1165
1166static netdev_features_t tun_net_fix_features(struct net_device *dev,
1167 netdev_features_t features)
1168{
1169 struct tun_struct *tun = netdev_priv(dev);
1170
1171 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1172}
1173
1174static void tun_set_headroom(struct net_device *dev, int new_hr)
1175{
1176 struct tun_struct *tun = netdev_priv(dev);
1177
1178 if (new_hr < NET_SKB_PAD)
1179 new_hr = NET_SKB_PAD;
1180
1181 tun->align = new_hr;
1182}
1183
1184static void
1185tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1186{
1187 struct tun_struct *tun = netdev_priv(dev);
1188
1189 dev_get_tstats64(dev, stats);
1190
1191 stats->rx_frame_errors +=
1192 (unsigned long)atomic_long_read(&tun->rx_frame_errors);
1193}
1194
1195static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1196 struct netlink_ext_ack *extack)
1197{
1198 struct tun_struct *tun = netdev_priv(dev);
1199 struct tun_file *tfile;
1200 struct bpf_prog *old_prog;
1201 int i;
1202
1203 old_prog = rtnl_dereference(tun->xdp_prog);
1204 rcu_assign_pointer(tun->xdp_prog, prog);
1205 if (old_prog)
1206 bpf_prog_put(old_prog);
1207
1208 for (i = 0; i < tun->numqueues; i++) {
1209 tfile = rtnl_dereference(tun->tfiles[i]);
1210 if (prog)
1211 sock_set_flag(&tfile->sk, SOCK_XDP);
1212 else
1213 sock_reset_flag(&tfile->sk, SOCK_XDP);
1214 }
1215 list_for_each_entry(tfile, &tun->disabled, next) {
1216 if (prog)
1217 sock_set_flag(&tfile->sk, SOCK_XDP);
1218 else
1219 sock_reset_flag(&tfile->sk, SOCK_XDP);
1220 }
1221
1222 return 0;
1223}
1224
1225static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1226{
1227 switch (xdp->command) {
1228 case XDP_SETUP_PROG:
1229 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1230 default:
1231 return -EINVAL;
1232 }
1233}
1234
1235static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1236{
1237 if (new_carrier) {
1238 struct tun_struct *tun = netdev_priv(dev);
1239
1240 if (!tun->numqueues)
1241 return -EPERM;
1242
1243 netif_carrier_on(dev);
1244 } else {
1245 netif_carrier_off(dev);
1246 }
1247 return 0;
1248}
1249
1250static const struct net_device_ops tun_netdev_ops = {
1251 .ndo_init = tun_net_init,
1252 .ndo_uninit = tun_net_uninit,
1253 .ndo_open = tun_net_open,
1254 .ndo_stop = tun_net_close,
1255 .ndo_start_xmit = tun_net_xmit,
1256 .ndo_fix_features = tun_net_fix_features,
1257 .ndo_select_queue = tun_select_queue,
1258 .ndo_set_rx_headroom = tun_set_headroom,
1259 .ndo_get_stats64 = tun_net_get_stats64,
1260 .ndo_change_carrier = tun_net_change_carrier,
1261};
1262
1263static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1264{
1265 /* Notify and wake up reader process */
1266 if (tfile->flags & TUN_FASYNC)
1267 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1268 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1269}
1270
1271static int tun_xdp_xmit(struct net_device *dev, int n,
1272 struct xdp_frame **frames, u32 flags)
1273{
1274 struct tun_struct *tun = netdev_priv(dev);
1275 struct tun_file *tfile;
1276 u32 numqueues;
1277 int nxmit = 0;
1278 int i;
1279
1280 if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1281 return -EINVAL;
1282
1283 rcu_read_lock();
1284
1285resample:
1286 numqueues = READ_ONCE(tun->numqueues);
1287 if (!numqueues) {
1288 rcu_read_unlock();
1289 return -ENXIO; /* Caller will free/return all frames */
1290 }
1291
1292 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1293 numqueues]);
1294 if (unlikely(!tfile))
1295 goto resample;
1296
1297 spin_lock(&tfile->tx_ring.producer_lock);
1298 for (i = 0; i < n; i++) {
1299 struct xdp_frame *xdp = frames[i];
1300 /* Encode the XDP flag into lowest bit for consumer to differ
1301 * XDP buffer from sk_buff.
1302 */
1303 void *frame = tun_xdp_to_ptr(xdp);
1304
1305 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1306 dev_core_stats_tx_dropped_inc(dev);
1307 break;
1308 }
1309 nxmit++;
1310 }
1311 spin_unlock(&tfile->tx_ring.producer_lock);
1312
1313 if (flags & XDP_XMIT_FLUSH)
1314 __tun_xdp_flush_tfile(tfile);
1315
1316 rcu_read_unlock();
1317 return nxmit;
1318}
1319
1320static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1321{
1322 struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
1323 int nxmit;
1324
1325 if (unlikely(!frame))
1326 return -EOVERFLOW;
1327
1328 nxmit = tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1329 if (!nxmit)
1330 xdp_return_frame_rx_napi(frame);
1331 return nxmit;
1332}
1333
1334static const struct net_device_ops tap_netdev_ops = {
1335 .ndo_init = tun_net_init,
1336 .ndo_uninit = tun_net_uninit,
1337 .ndo_open = tun_net_open,
1338 .ndo_stop = tun_net_close,
1339 .ndo_start_xmit = tun_net_xmit,
1340 .ndo_fix_features = tun_net_fix_features,
1341 .ndo_set_rx_mode = tun_net_mclist,
1342 .ndo_set_mac_address = eth_mac_addr,
1343 .ndo_validate_addr = eth_validate_addr,
1344 .ndo_select_queue = tun_select_queue,
1345 .ndo_features_check = passthru_features_check,
1346 .ndo_set_rx_headroom = tun_set_headroom,
1347 .ndo_get_stats64 = dev_get_tstats64,
1348 .ndo_bpf = tun_xdp,
1349 .ndo_xdp_xmit = tun_xdp_xmit,
1350 .ndo_change_carrier = tun_net_change_carrier,
1351};
1352
1353static void tun_flow_init(struct tun_struct *tun)
1354{
1355 int i;
1356
1357 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1358 INIT_HLIST_HEAD(&tun->flows[i]);
1359
1360 tun->ageing_time = TUN_FLOW_EXPIRE;
1361 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1362 mod_timer(&tun->flow_gc_timer,
1363 round_jiffies_up(jiffies + tun->ageing_time));
1364}
1365
1366static void tun_flow_uninit(struct tun_struct *tun)
1367{
1368 del_timer_sync(&tun->flow_gc_timer);
1369 tun_flow_flush(tun);
1370}
1371
1372#define MIN_MTU 68
1373#define MAX_MTU 65535
1374
1375/* Initialize net device. */
1376static void tun_net_initialize(struct net_device *dev)
1377{
1378 struct tun_struct *tun = netdev_priv(dev);
1379
1380 switch (tun->flags & TUN_TYPE_MASK) {
1381 case IFF_TUN:
1382 dev->netdev_ops = &tun_netdev_ops;
1383 dev->header_ops = &ip_tunnel_header_ops;
1384
1385 /* Point-to-Point TUN Device */
1386 dev->hard_header_len = 0;
1387 dev->addr_len = 0;
1388 dev->mtu = 1500;
1389
1390 /* Zero header length */
1391 dev->type = ARPHRD_NONE;
1392 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1393 break;
1394
1395 case IFF_TAP:
1396 dev->netdev_ops = &tap_netdev_ops;
1397 /* Ethernet TAP Device */
1398 ether_setup(dev);
1399 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1400 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1401
1402 eth_hw_addr_random(dev);
1403
1404 break;
1405 }
1406
1407 dev->min_mtu = MIN_MTU;
1408 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1409}
1410
1411static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1412{
1413 struct sock *sk = tfile->socket.sk;
1414
1415 return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1416}
1417
1418/* Character device part */
1419
1420/* Poll */
1421static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1422{
1423 struct tun_file *tfile = file->private_data;
1424 struct tun_struct *tun = tun_get(tfile);
1425 struct sock *sk;
1426 __poll_t mask = 0;
1427
1428 if (!tun)
1429 return EPOLLERR;
1430
1431 sk = tfile->socket.sk;
1432
1433 poll_wait(file, sk_sleep(sk), wait);
1434
1435 if (!ptr_ring_empty(&tfile->tx_ring))
1436 mask |= EPOLLIN | EPOLLRDNORM;
1437
1438 /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1439 * guarantee EPOLLOUT to be raised by either here or
1440 * tun_sock_write_space(). Then process could get notification
1441 * after it writes to a down device and meets -EIO.
1442 */
1443 if (tun_sock_writeable(tun, tfile) ||
1444 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1445 tun_sock_writeable(tun, tfile)))
1446 mask |= EPOLLOUT | EPOLLWRNORM;
1447
1448 if (tun->dev->reg_state != NETREG_REGISTERED)
1449 mask = EPOLLERR;
1450
1451 tun_put(tun);
1452 return mask;
1453}
1454
1455static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1456 size_t len,
1457 const struct iov_iter *it)
1458{
1459 struct sk_buff *skb;
1460 size_t linear;
1461 int err;
1462 int i;
1463
1464 if (it->nr_segs > MAX_SKB_FRAGS + 1 ||
1465 len > (ETH_MAX_MTU - NET_SKB_PAD - NET_IP_ALIGN))
1466 return ERR_PTR(-EMSGSIZE);
1467
1468 local_bh_disable();
1469 skb = napi_get_frags(&tfile->napi);
1470 local_bh_enable();
1471 if (!skb)
1472 return ERR_PTR(-ENOMEM);
1473
1474 linear = iov_iter_single_seg_count(it);
1475 err = __skb_grow(skb, linear);
1476 if (err)
1477 goto free;
1478
1479 skb->len = len;
1480 skb->data_len = len - linear;
1481 skb->truesize += skb->data_len;
1482
1483 for (i = 1; i < it->nr_segs; i++) {
1484 size_t fragsz = it->iov[i].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;
1503free:
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). */
1511static 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 || !linear)
1521 linear = len;
1522
1523 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1524 &err, 0);
1525 if (!skb)
1526 return ERR_PTR(err);
1527
1528 skb_reserve(skb, prepad);
1529 skb_put(skb, linear);
1530 skb->data_len = len - linear;
1531 skb->len += len - linear;
1532
1533 return skb;
1534}
1535
1536static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1537 struct sk_buff *skb, int more)
1538{
1539 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1540 struct sk_buff_head process_queue;
1541 u32 rx_batched = tun->rx_batched;
1542 bool rcv = false;
1543
1544 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1545 local_bh_disable();
1546 skb_record_rx_queue(skb, tfile->queue_index);
1547 netif_receive_skb(skb);
1548 local_bh_enable();
1549 return;
1550 }
1551
1552 spin_lock(&queue->lock);
1553 if (!more || skb_queue_len(queue) == rx_batched) {
1554 __skb_queue_head_init(&process_queue);
1555 skb_queue_splice_tail_init(queue, &process_queue);
1556 rcv = true;
1557 } else {
1558 __skb_queue_tail(queue, skb);
1559 }
1560 spin_unlock(&queue->lock);
1561
1562 if (rcv) {
1563 struct sk_buff *nskb;
1564
1565 local_bh_disable();
1566 while ((nskb = __skb_dequeue(&process_queue))) {
1567 skb_record_rx_queue(nskb, tfile->queue_index);
1568 netif_receive_skb(nskb);
1569 }
1570 skb_record_rx_queue(skb, tfile->queue_index);
1571 netif_receive_skb(skb);
1572 local_bh_enable();
1573 }
1574}
1575
1576static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1577 int len, int noblock, bool zerocopy)
1578{
1579 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1580 return false;
1581
1582 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1583 return false;
1584
1585 if (!noblock)
1586 return false;
1587
1588 if (zerocopy)
1589 return false;
1590
1591 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1592 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1593 return false;
1594
1595 return true;
1596}
1597
1598static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
1599 struct page_frag *alloc_frag, char *buf,
1600 int buflen, int len, int pad)
1601{
1602 struct sk_buff *skb = build_skb(buf, buflen);
1603
1604 if (!skb)
1605 return ERR_PTR(-ENOMEM);
1606
1607 skb_reserve(skb, pad);
1608 skb_put(skb, len);
1609 skb_set_owner_w(skb, tfile->socket.sk);
1610
1611 get_page(alloc_frag->page);
1612 alloc_frag->offset += buflen;
1613
1614 return skb;
1615}
1616
1617static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1618 struct xdp_buff *xdp, u32 act)
1619{
1620 int err;
1621
1622 switch (act) {
1623 case XDP_REDIRECT:
1624 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1625 if (err)
1626 return err;
1627 break;
1628 case XDP_TX:
1629 err = tun_xdp_tx(tun->dev, xdp);
1630 if (err < 0)
1631 return err;
1632 break;
1633 case XDP_PASS:
1634 break;
1635 default:
1636 bpf_warn_invalid_xdp_action(tun->dev, xdp_prog, act);
1637 fallthrough;
1638 case XDP_ABORTED:
1639 trace_xdp_exception(tun->dev, xdp_prog, act);
1640 fallthrough;
1641 case XDP_DROP:
1642 dev_core_stats_rx_dropped_inc(tun->dev);
1643 break;
1644 }
1645
1646 return act;
1647}
1648
1649static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1650 struct tun_file *tfile,
1651 struct iov_iter *from,
1652 struct virtio_net_hdr *hdr,
1653 int len, int *skb_xdp)
1654{
1655 struct page_frag *alloc_frag = ¤t->task_frag;
1656 struct bpf_prog *xdp_prog;
1657 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1658 char *buf;
1659 size_t copied;
1660 int pad = TUN_RX_PAD;
1661 int err = 0;
1662
1663 rcu_read_lock();
1664 xdp_prog = rcu_dereference(tun->xdp_prog);
1665 if (xdp_prog)
1666 pad += XDP_PACKET_HEADROOM;
1667 buflen += SKB_DATA_ALIGN(len + pad);
1668 rcu_read_unlock();
1669
1670 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1671 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1672 return ERR_PTR(-ENOMEM);
1673
1674 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1675 copied = copy_page_from_iter(alloc_frag->page,
1676 alloc_frag->offset + pad,
1677 len, from);
1678 if (copied != len)
1679 return ERR_PTR(-EFAULT);
1680
1681 /* There's a small window that XDP may be set after the check
1682 * of xdp_prog above, this should be rare and for simplicity
1683 * we do XDP on skb in case the headroom is not enough.
1684 */
1685 if (hdr->gso_type || !xdp_prog) {
1686 *skb_xdp = 1;
1687 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len,
1688 pad);
1689 }
1690
1691 *skb_xdp = 0;
1692
1693 local_bh_disable();
1694 rcu_read_lock();
1695 xdp_prog = rcu_dereference(tun->xdp_prog);
1696 if (xdp_prog) {
1697 struct xdp_buff xdp;
1698 u32 act;
1699
1700 xdp_init_buff(&xdp, buflen, &tfile->xdp_rxq);
1701 xdp_prepare_buff(&xdp, buf, pad, len, false);
1702
1703 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1704 if (act == XDP_REDIRECT || act == XDP_TX) {
1705 get_page(alloc_frag->page);
1706 alloc_frag->offset += buflen;
1707 }
1708 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1709 if (err < 0) {
1710 if (act == XDP_REDIRECT || act == XDP_TX)
1711 put_page(alloc_frag->page);
1712 goto out;
1713 }
1714
1715 if (err == XDP_REDIRECT)
1716 xdp_do_flush();
1717 if (err != XDP_PASS)
1718 goto out;
1719
1720 pad = xdp.data - xdp.data_hard_start;
1721 len = xdp.data_end - xdp.data;
1722 }
1723 rcu_read_unlock();
1724 local_bh_enable();
1725
1726 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1727
1728out:
1729 rcu_read_unlock();
1730 local_bh_enable();
1731 return NULL;
1732}
1733
1734/* Get packet from user space buffer */
1735static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1736 void *msg_control, struct iov_iter *from,
1737 int noblock, bool more)
1738{
1739 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1740 struct sk_buff *skb;
1741 size_t total_len = iov_iter_count(from);
1742 size_t len = total_len, align = tun->align, linear;
1743 struct virtio_net_hdr gso = { 0 };
1744 int good_linear;
1745 int copylen;
1746 bool zerocopy = false;
1747 int err;
1748 u32 rxhash = 0;
1749 int skb_xdp = 1;
1750 bool frags = tun_napi_frags_enabled(tfile);
1751 enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
1752
1753 if (!(tun->flags & IFF_NO_PI)) {
1754 if (len < sizeof(pi))
1755 return -EINVAL;
1756 len -= sizeof(pi);
1757
1758 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1759 return -EFAULT;
1760 }
1761
1762 if (tun->flags & IFF_VNET_HDR) {
1763 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1764
1765 if (len < vnet_hdr_sz)
1766 return -EINVAL;
1767 len -= vnet_hdr_sz;
1768
1769 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1770 return -EFAULT;
1771
1772 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1773 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1774 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1775
1776 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1777 return -EINVAL;
1778 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1779 }
1780
1781 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1782 align += NET_IP_ALIGN;
1783 if (unlikely(len < ETH_HLEN ||
1784 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1785 return -EINVAL;
1786 }
1787
1788 good_linear = SKB_MAX_HEAD(align);
1789
1790 if (msg_control) {
1791 struct iov_iter i = *from;
1792
1793 /* There are 256 bytes to be copied in skb, so there is
1794 * enough room for skb expand head in case it is used.
1795 * The rest of the buffer is mapped from userspace.
1796 */
1797 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1798 if (copylen > good_linear)
1799 copylen = good_linear;
1800 linear = copylen;
1801 iov_iter_advance(&i, copylen);
1802 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1803 zerocopy = true;
1804 }
1805
1806 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1807 /* For the packet that is not easy to be processed
1808 * (e.g gso or jumbo packet), we will do it at after
1809 * skb was created with generic XDP routine.
1810 */
1811 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1812 err = PTR_ERR_OR_ZERO(skb);
1813 if (err)
1814 goto drop;
1815 if (!skb)
1816 return total_len;
1817 } else {
1818 if (!zerocopy) {
1819 copylen = len;
1820 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1821 linear = good_linear;
1822 else
1823 linear = tun16_to_cpu(tun, gso.hdr_len);
1824 }
1825
1826 if (frags) {
1827 mutex_lock(&tfile->napi_mutex);
1828 skb = tun_napi_alloc_frags(tfile, copylen, from);
1829 /* tun_napi_alloc_frags() enforces a layout for the skb.
1830 * If zerocopy is enabled, then this layout will be
1831 * overwritten by zerocopy_sg_from_iter().
1832 */
1833 zerocopy = false;
1834 } else {
1835 skb = tun_alloc_skb(tfile, align, copylen, linear,
1836 noblock);
1837 }
1838
1839 err = PTR_ERR_OR_ZERO(skb);
1840 if (err)
1841 goto drop;
1842
1843 if (zerocopy)
1844 err = zerocopy_sg_from_iter(skb, from);
1845 else
1846 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1847
1848 if (err) {
1849 err = -EFAULT;
1850 drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
1851 goto drop;
1852 }
1853 }
1854
1855 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1856 atomic_long_inc(&tun->rx_frame_errors);
1857 err = -EINVAL;
1858 goto free_skb;
1859 }
1860
1861 switch (tun->flags & TUN_TYPE_MASK) {
1862 case IFF_TUN:
1863 if (tun->flags & IFF_NO_PI) {
1864 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1865
1866 switch (ip_version) {
1867 case 4:
1868 pi.proto = htons(ETH_P_IP);
1869 break;
1870 case 6:
1871 pi.proto = htons(ETH_P_IPV6);
1872 break;
1873 default:
1874 err = -EINVAL;
1875 goto drop;
1876 }
1877 }
1878
1879 skb_reset_mac_header(skb);
1880 skb->protocol = pi.proto;
1881 skb->dev = tun->dev;
1882 break;
1883 case IFF_TAP:
1884 if (frags && !pskb_may_pull(skb, ETH_HLEN)) {
1885 err = -ENOMEM;
1886 drop_reason = SKB_DROP_REASON_HDR_TRUNC;
1887 goto drop;
1888 }
1889 skb->protocol = eth_type_trans(skb, tun->dev);
1890 break;
1891 }
1892
1893 /* copy skb_ubuf_info for callback when skb has no error */
1894 if (zerocopy) {
1895 skb_zcopy_init(skb, msg_control);
1896 } else if (msg_control) {
1897 struct ubuf_info *uarg = msg_control;
1898 uarg->callback(NULL, uarg, false);
1899 }
1900
1901 skb_reset_network_header(skb);
1902 skb_probe_transport_header(skb);
1903 skb_record_rx_queue(skb, tfile->queue_index);
1904
1905 if (skb_xdp) {
1906 struct bpf_prog *xdp_prog;
1907 int ret;
1908
1909 local_bh_disable();
1910 rcu_read_lock();
1911 xdp_prog = rcu_dereference(tun->xdp_prog);
1912 if (xdp_prog) {
1913 ret = do_xdp_generic(xdp_prog, skb);
1914 if (ret != XDP_PASS) {
1915 rcu_read_unlock();
1916 local_bh_enable();
1917 goto unlock_frags;
1918 }
1919 }
1920 rcu_read_unlock();
1921 local_bh_enable();
1922 }
1923
1924 /* Compute the costly rx hash only if needed for flow updates.
1925 * We may get a very small possibility of OOO during switching, not
1926 * worth to optimize.
1927 */
1928 if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1929 !tfile->detached)
1930 rxhash = __skb_get_hash_symmetric(skb);
1931
1932 rcu_read_lock();
1933 if (unlikely(!(tun->dev->flags & IFF_UP))) {
1934 err = -EIO;
1935 rcu_read_unlock();
1936 drop_reason = SKB_DROP_REASON_DEV_READY;
1937 goto drop;
1938 }
1939
1940 if (frags) {
1941 u32 headlen;
1942
1943 /* Exercise flow dissector code path. */
1944 skb_push(skb, ETH_HLEN);
1945 headlen = eth_get_headlen(tun->dev, skb->data,
1946 skb_headlen(skb));
1947
1948 if (unlikely(headlen > skb_headlen(skb))) {
1949 WARN_ON_ONCE(1);
1950 err = -ENOMEM;
1951 dev_core_stats_rx_dropped_inc(tun->dev);
1952napi_busy:
1953 napi_free_frags(&tfile->napi);
1954 rcu_read_unlock();
1955 mutex_unlock(&tfile->napi_mutex);
1956 return err;
1957 }
1958
1959 if (likely(napi_schedule_prep(&tfile->napi))) {
1960 local_bh_disable();
1961 napi_gro_frags(&tfile->napi);
1962 napi_complete(&tfile->napi);
1963 local_bh_enable();
1964 } else {
1965 err = -EBUSY;
1966 goto napi_busy;
1967 }
1968 mutex_unlock(&tfile->napi_mutex);
1969 } else if (tfile->napi_enabled) {
1970 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1971 int queue_len;
1972
1973 spin_lock_bh(&queue->lock);
1974 __skb_queue_tail(queue, skb);
1975 queue_len = skb_queue_len(queue);
1976 spin_unlock(&queue->lock);
1977
1978 if (!more || queue_len > NAPI_POLL_WEIGHT)
1979 napi_schedule(&tfile->napi);
1980
1981 local_bh_enable();
1982 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1983 tun_rx_batched(tun, tfile, skb, more);
1984 } else {
1985 netif_rx(skb);
1986 }
1987 rcu_read_unlock();
1988
1989 preempt_disable();
1990 dev_sw_netstats_rx_add(tun->dev, len);
1991 preempt_enable();
1992
1993 if (rxhash)
1994 tun_flow_update(tun, rxhash, tfile);
1995
1996 return total_len;
1997
1998drop:
1999 if (err != -EAGAIN)
2000 dev_core_stats_rx_dropped_inc(tun->dev);
2001
2002free_skb:
2003 if (!IS_ERR_OR_NULL(skb))
2004 kfree_skb_reason(skb, drop_reason);
2005
2006unlock_frags:
2007 if (frags) {
2008 tfile->napi.skb = NULL;
2009 mutex_unlock(&tfile->napi_mutex);
2010 }
2011
2012 return err ?: total_len;
2013}
2014
2015static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
2016{
2017 struct file *file = iocb->ki_filp;
2018 struct tun_file *tfile = file->private_data;
2019 struct tun_struct *tun = tun_get(tfile);
2020 ssize_t result;
2021 int noblock = 0;
2022
2023 if (!tun)
2024 return -EBADFD;
2025
2026 if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
2027 noblock = 1;
2028
2029 result = tun_get_user(tun, tfile, NULL, from, noblock, false);
2030
2031 tun_put(tun);
2032 return result;
2033}
2034
2035static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2036 struct tun_file *tfile,
2037 struct xdp_frame *xdp_frame,
2038 struct iov_iter *iter)
2039{
2040 int vnet_hdr_sz = 0;
2041 size_t size = xdp_frame->len;
2042 size_t ret;
2043
2044 if (tun->flags & IFF_VNET_HDR) {
2045 struct virtio_net_hdr gso = { 0 };
2046
2047 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2048 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2049 return -EINVAL;
2050 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2051 sizeof(gso)))
2052 return -EFAULT;
2053 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2054 }
2055
2056 ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2057
2058 preempt_disable();
2059 dev_sw_netstats_tx_add(tun->dev, 1, ret);
2060 preempt_enable();
2061
2062 return ret;
2063}
2064
2065/* Put packet to the user space buffer */
2066static ssize_t tun_put_user(struct tun_struct *tun,
2067 struct tun_file *tfile,
2068 struct sk_buff *skb,
2069 struct iov_iter *iter)
2070{
2071 struct tun_pi pi = { 0, skb->protocol };
2072 ssize_t total;
2073 int vlan_offset = 0;
2074 int vlan_hlen = 0;
2075 int vnet_hdr_sz = 0;
2076
2077 if (skb_vlan_tag_present(skb))
2078 vlan_hlen = VLAN_HLEN;
2079
2080 if (tun->flags & IFF_VNET_HDR)
2081 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2082
2083 total = skb->len + vlan_hlen + vnet_hdr_sz;
2084
2085 if (!(tun->flags & IFF_NO_PI)) {
2086 if (iov_iter_count(iter) < sizeof(pi))
2087 return -EINVAL;
2088
2089 total += sizeof(pi);
2090 if (iov_iter_count(iter) < total) {
2091 /* Packet will be striped */
2092 pi.flags |= TUN_PKT_STRIP;
2093 }
2094
2095 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2096 return -EFAULT;
2097 }
2098
2099 if (vnet_hdr_sz) {
2100 struct virtio_net_hdr gso;
2101
2102 if (iov_iter_count(iter) < vnet_hdr_sz)
2103 return -EINVAL;
2104
2105 if (virtio_net_hdr_from_skb(skb, &gso,
2106 tun_is_little_endian(tun), true,
2107 vlan_hlen)) {
2108 struct skb_shared_info *sinfo = skb_shinfo(skb);
2109 pr_err("unexpected GSO type: "
2110 "0x%x, gso_size %d, hdr_len %d\n",
2111 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2112 tun16_to_cpu(tun, gso.hdr_len));
2113 print_hex_dump(KERN_ERR, "tun: ",
2114 DUMP_PREFIX_NONE,
2115 16, 1, skb->head,
2116 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2117 WARN_ON_ONCE(1);
2118 return -EINVAL;
2119 }
2120
2121 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2122 return -EFAULT;
2123
2124 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2125 }
2126
2127 if (vlan_hlen) {
2128 int ret;
2129 struct veth veth;
2130
2131 veth.h_vlan_proto = skb->vlan_proto;
2132 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2133
2134 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2135
2136 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2137 if (ret || !iov_iter_count(iter))
2138 goto done;
2139
2140 ret = copy_to_iter(&veth, sizeof(veth), iter);
2141 if (ret != sizeof(veth) || !iov_iter_count(iter))
2142 goto done;
2143 }
2144
2145 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2146
2147done:
2148 /* caller is in process context, */
2149 preempt_disable();
2150 dev_sw_netstats_tx_add(tun->dev, 1, skb->len + vlan_hlen);
2151 preempt_enable();
2152
2153 return total;
2154}
2155
2156static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2157{
2158 DECLARE_WAITQUEUE(wait, current);
2159 void *ptr = NULL;
2160 int error = 0;
2161
2162 ptr = ptr_ring_consume(&tfile->tx_ring);
2163 if (ptr)
2164 goto out;
2165 if (noblock) {
2166 error = -EAGAIN;
2167 goto out;
2168 }
2169
2170 add_wait_queue(&tfile->socket.wq.wait, &wait);
2171
2172 while (1) {
2173 set_current_state(TASK_INTERRUPTIBLE);
2174 ptr = ptr_ring_consume(&tfile->tx_ring);
2175 if (ptr)
2176 break;
2177 if (signal_pending(current)) {
2178 error = -ERESTARTSYS;
2179 break;
2180 }
2181 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2182 error = -EFAULT;
2183 break;
2184 }
2185
2186 schedule();
2187 }
2188
2189 __set_current_state(TASK_RUNNING);
2190 remove_wait_queue(&tfile->socket.wq.wait, &wait);
2191
2192out:
2193 *err = error;
2194 return ptr;
2195}
2196
2197static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2198 struct iov_iter *to,
2199 int noblock, void *ptr)
2200{
2201 ssize_t ret;
2202 int err;
2203
2204 if (!iov_iter_count(to)) {
2205 tun_ptr_free(ptr);
2206 return 0;
2207 }
2208
2209 if (!ptr) {
2210 /* Read frames from ring */
2211 ptr = tun_ring_recv(tfile, noblock, &err);
2212 if (!ptr)
2213 return err;
2214 }
2215
2216 if (tun_is_xdp_frame(ptr)) {
2217 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2218
2219 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2220 xdp_return_frame(xdpf);
2221 } else {
2222 struct sk_buff *skb = ptr;
2223
2224 ret = tun_put_user(tun, tfile, skb, to);
2225 if (unlikely(ret < 0))
2226 kfree_skb(skb);
2227 else
2228 consume_skb(skb);
2229 }
2230
2231 return ret;
2232}
2233
2234static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2235{
2236 struct file *file = iocb->ki_filp;
2237 struct tun_file *tfile = file->private_data;
2238 struct tun_struct *tun = tun_get(tfile);
2239 ssize_t len = iov_iter_count(to), ret;
2240 int noblock = 0;
2241
2242 if (!tun)
2243 return -EBADFD;
2244
2245 if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
2246 noblock = 1;
2247
2248 ret = tun_do_read(tun, tfile, to, noblock, NULL);
2249 ret = min_t(ssize_t, ret, len);
2250 if (ret > 0)
2251 iocb->ki_pos = ret;
2252 tun_put(tun);
2253 return ret;
2254}
2255
2256static void tun_prog_free(struct rcu_head *rcu)
2257{
2258 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2259
2260 bpf_prog_destroy(prog->prog);
2261 kfree(prog);
2262}
2263
2264static int __tun_set_ebpf(struct tun_struct *tun,
2265 struct tun_prog __rcu **prog_p,
2266 struct bpf_prog *prog)
2267{
2268 struct tun_prog *old, *new = NULL;
2269
2270 if (prog) {
2271 new = kmalloc(sizeof(*new), GFP_KERNEL);
2272 if (!new)
2273 return -ENOMEM;
2274 new->prog = prog;
2275 }
2276
2277 spin_lock_bh(&tun->lock);
2278 old = rcu_dereference_protected(*prog_p,
2279 lockdep_is_held(&tun->lock));
2280 rcu_assign_pointer(*prog_p, new);
2281 spin_unlock_bh(&tun->lock);
2282
2283 if (old)
2284 call_rcu(&old->rcu, tun_prog_free);
2285
2286 return 0;
2287}
2288
2289static void tun_free_netdev(struct net_device *dev)
2290{
2291 struct tun_struct *tun = netdev_priv(dev);
2292
2293 BUG_ON(!(list_empty(&tun->disabled)));
2294
2295 free_percpu(dev->tstats);
2296 tun_flow_uninit(tun);
2297 security_tun_dev_free_security(tun->security);
2298 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2299 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2300}
2301
2302static void tun_setup(struct net_device *dev)
2303{
2304 struct tun_struct *tun = netdev_priv(dev);
2305
2306 tun->owner = INVALID_UID;
2307 tun->group = INVALID_GID;
2308 tun_default_link_ksettings(dev, &tun->link_ksettings);
2309
2310 dev->ethtool_ops = &tun_ethtool_ops;
2311 dev->needs_free_netdev = true;
2312 dev->priv_destructor = tun_free_netdev;
2313 /* We prefer our own queue length */
2314 dev->tx_queue_len = TUN_READQ_SIZE;
2315}
2316
2317/* Trivial set of netlink ops to allow deleting tun or tap
2318 * device with netlink.
2319 */
2320static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2321 struct netlink_ext_ack *extack)
2322{
2323 NL_SET_ERR_MSG(extack,
2324 "tun/tap creation via rtnetlink is not supported.");
2325 return -EOPNOTSUPP;
2326}
2327
2328static size_t tun_get_size(const struct net_device *dev)
2329{
2330 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2331 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2332
2333 return nla_total_size(sizeof(uid_t)) + /* OWNER */
2334 nla_total_size(sizeof(gid_t)) + /* GROUP */
2335 nla_total_size(sizeof(u8)) + /* TYPE */
2336 nla_total_size(sizeof(u8)) + /* PI */
2337 nla_total_size(sizeof(u8)) + /* VNET_HDR */
2338 nla_total_size(sizeof(u8)) + /* PERSIST */
2339 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2340 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2341 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2342 0;
2343}
2344
2345static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2346{
2347 struct tun_struct *tun = netdev_priv(dev);
2348
2349 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2350 goto nla_put_failure;
2351 if (uid_valid(tun->owner) &&
2352 nla_put_u32(skb, IFLA_TUN_OWNER,
2353 from_kuid_munged(current_user_ns(), tun->owner)))
2354 goto nla_put_failure;
2355 if (gid_valid(tun->group) &&
2356 nla_put_u32(skb, IFLA_TUN_GROUP,
2357 from_kgid_munged(current_user_ns(), tun->group)))
2358 goto nla_put_failure;
2359 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2360 goto nla_put_failure;
2361 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2362 goto nla_put_failure;
2363 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2364 goto nla_put_failure;
2365 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2366 !!(tun->flags & IFF_MULTI_QUEUE)))
2367 goto nla_put_failure;
2368 if (tun->flags & IFF_MULTI_QUEUE) {
2369 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2370 goto nla_put_failure;
2371 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2372 tun->numdisabled))
2373 goto nla_put_failure;
2374 }
2375
2376 return 0;
2377
2378nla_put_failure:
2379 return -EMSGSIZE;
2380}
2381
2382static struct rtnl_link_ops tun_link_ops __read_mostly = {
2383 .kind = DRV_NAME,
2384 .priv_size = sizeof(struct tun_struct),
2385 .setup = tun_setup,
2386 .validate = tun_validate,
2387 .get_size = tun_get_size,
2388 .fill_info = tun_fill_info,
2389};
2390
2391static void tun_sock_write_space(struct sock *sk)
2392{
2393 struct tun_file *tfile;
2394 wait_queue_head_t *wqueue;
2395
2396 if (!sock_writeable(sk))
2397 return;
2398
2399 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2400 return;
2401
2402 wqueue = sk_sleep(sk);
2403 if (wqueue && waitqueue_active(wqueue))
2404 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2405 EPOLLWRNORM | EPOLLWRBAND);
2406
2407 tfile = container_of(sk, struct tun_file, sk);
2408 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2409}
2410
2411static void tun_put_page(struct tun_page *tpage)
2412{
2413 if (tpage->page)
2414 __page_frag_cache_drain(tpage->page, tpage->count);
2415}
2416
2417static int tun_xdp_one(struct tun_struct *tun,
2418 struct tun_file *tfile,
2419 struct xdp_buff *xdp, int *flush,
2420 struct tun_page *tpage)
2421{
2422 unsigned int datasize = xdp->data_end - xdp->data;
2423 struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2424 struct virtio_net_hdr *gso = &hdr->gso;
2425 struct bpf_prog *xdp_prog;
2426 struct sk_buff *skb = NULL;
2427 struct sk_buff_head *queue;
2428 u32 rxhash = 0, act;
2429 int buflen = hdr->buflen;
2430 int ret = 0;
2431 bool skb_xdp = false;
2432 struct page *page;
2433
2434 xdp_prog = rcu_dereference(tun->xdp_prog);
2435 if (xdp_prog) {
2436 if (gso->gso_type) {
2437 skb_xdp = true;
2438 goto build;
2439 }
2440
2441 xdp_init_buff(xdp, buflen, &tfile->xdp_rxq);
2442 xdp_set_data_meta_invalid(xdp);
2443
2444 act = bpf_prog_run_xdp(xdp_prog, xdp);
2445 ret = tun_xdp_act(tun, xdp_prog, xdp, act);
2446 if (ret < 0) {
2447 put_page(virt_to_head_page(xdp->data));
2448 return ret;
2449 }
2450
2451 switch (ret) {
2452 case XDP_REDIRECT:
2453 *flush = true;
2454 fallthrough;
2455 case XDP_TX:
2456 return 0;
2457 case XDP_PASS:
2458 break;
2459 default:
2460 page = virt_to_head_page(xdp->data);
2461 if (tpage->page == page) {
2462 ++tpage->count;
2463 } else {
2464 tun_put_page(tpage);
2465 tpage->page = page;
2466 tpage->count = 1;
2467 }
2468 return 0;
2469 }
2470 }
2471
2472build:
2473 skb = build_skb(xdp->data_hard_start, buflen);
2474 if (!skb) {
2475 ret = -ENOMEM;
2476 goto out;
2477 }
2478
2479 skb_reserve(skb, xdp->data - xdp->data_hard_start);
2480 skb_put(skb, xdp->data_end - xdp->data);
2481
2482 if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2483 atomic_long_inc(&tun->rx_frame_errors);
2484 kfree_skb(skb);
2485 ret = -EINVAL;
2486 goto out;
2487 }
2488
2489 skb->protocol = eth_type_trans(skb, tun->dev);
2490 skb_reset_network_header(skb);
2491 skb_probe_transport_header(skb);
2492 skb_record_rx_queue(skb, tfile->queue_index);
2493
2494 if (skb_xdp) {
2495 ret = do_xdp_generic(xdp_prog, skb);
2496 if (ret != XDP_PASS) {
2497 ret = 0;
2498 goto out;
2499 }
2500 }
2501
2502 if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2503 !tfile->detached)
2504 rxhash = __skb_get_hash_symmetric(skb);
2505
2506 if (tfile->napi_enabled) {
2507 queue = &tfile->sk.sk_write_queue;
2508 spin_lock(&queue->lock);
2509 __skb_queue_tail(queue, skb);
2510 spin_unlock(&queue->lock);
2511 ret = 1;
2512 } else {
2513 netif_receive_skb(skb);
2514 ret = 0;
2515 }
2516
2517 /* No need to disable preemption here since this function is
2518 * always called with bh disabled
2519 */
2520 dev_sw_netstats_rx_add(tun->dev, datasize);
2521
2522 if (rxhash)
2523 tun_flow_update(tun, rxhash, tfile);
2524
2525out:
2526 return ret;
2527}
2528
2529static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2530{
2531 int ret, i;
2532 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2533 struct tun_struct *tun = tun_get(tfile);
2534 struct tun_msg_ctl *ctl = m->msg_control;
2535 struct xdp_buff *xdp;
2536
2537 if (!tun)
2538 return -EBADFD;
2539
2540 if (m->msg_controllen == sizeof(struct tun_msg_ctl) &&
2541 ctl && ctl->type == TUN_MSG_PTR) {
2542 struct tun_page tpage;
2543 int n = ctl->num;
2544 int flush = 0, queued = 0;
2545
2546 memset(&tpage, 0, sizeof(tpage));
2547
2548 local_bh_disable();
2549 rcu_read_lock();
2550
2551 for (i = 0; i < n; i++) {
2552 xdp = &((struct xdp_buff *)ctl->ptr)[i];
2553 ret = tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2554 if (ret > 0)
2555 queued += ret;
2556 }
2557
2558 if (flush)
2559 xdp_do_flush();
2560
2561 if (tfile->napi_enabled && queued > 0)
2562 napi_schedule(&tfile->napi);
2563
2564 rcu_read_unlock();
2565 local_bh_enable();
2566
2567 tun_put_page(&tpage);
2568
2569 ret = total_len;
2570 goto out;
2571 }
2572
2573 ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2574 m->msg_flags & MSG_DONTWAIT,
2575 m->msg_flags & MSG_MORE);
2576out:
2577 tun_put(tun);
2578 return ret;
2579}
2580
2581static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2582 int flags)
2583{
2584 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2585 struct tun_struct *tun = tun_get(tfile);
2586 void *ptr = m->msg_control;
2587 int ret;
2588
2589 if (!tun) {
2590 ret = -EBADFD;
2591 goto out_free;
2592 }
2593
2594 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2595 ret = -EINVAL;
2596 goto out_put_tun;
2597 }
2598 if (flags & MSG_ERRQUEUE) {
2599 ret = sock_recv_errqueue(sock->sk, m, total_len,
2600 SOL_PACKET, TUN_TX_TIMESTAMP);
2601 goto out;
2602 }
2603 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2604 if (ret > (ssize_t)total_len) {
2605 m->msg_flags |= MSG_TRUNC;
2606 ret = flags & MSG_TRUNC ? ret : total_len;
2607 }
2608out:
2609 tun_put(tun);
2610 return ret;
2611
2612out_put_tun:
2613 tun_put(tun);
2614out_free:
2615 tun_ptr_free(ptr);
2616 return ret;
2617}
2618
2619static int tun_ptr_peek_len(void *ptr)
2620{
2621 if (likely(ptr)) {
2622 if (tun_is_xdp_frame(ptr)) {
2623 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2624
2625 return xdpf->len;
2626 }
2627 return __skb_array_len_with_tag(ptr);
2628 } else {
2629 return 0;
2630 }
2631}
2632
2633static int tun_peek_len(struct socket *sock)
2634{
2635 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2636 struct tun_struct *tun;
2637 int ret = 0;
2638
2639 tun = tun_get(tfile);
2640 if (!tun)
2641 return 0;
2642
2643 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2644 tun_put(tun);
2645
2646 return ret;
2647}
2648
2649/* Ops structure to mimic raw sockets with tun */
2650static const struct proto_ops tun_socket_ops = {
2651 .peek_len = tun_peek_len,
2652 .sendmsg = tun_sendmsg,
2653 .recvmsg = tun_recvmsg,
2654};
2655
2656static struct proto tun_proto = {
2657 .name = "tun",
2658 .owner = THIS_MODULE,
2659 .obj_size = sizeof(struct tun_file),
2660};
2661
2662static int tun_flags(struct tun_struct *tun)
2663{
2664 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2665}
2666
2667static ssize_t tun_flags_show(struct device *dev, struct device_attribute *attr,
2668 char *buf)
2669{
2670 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2671 return sysfs_emit(buf, "0x%x\n", tun_flags(tun));
2672}
2673
2674static ssize_t owner_show(struct device *dev, struct device_attribute *attr,
2675 char *buf)
2676{
2677 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2678 return uid_valid(tun->owner)?
2679 sysfs_emit(buf, "%u\n",
2680 from_kuid_munged(current_user_ns(), tun->owner)) :
2681 sysfs_emit(buf, "-1\n");
2682}
2683
2684static ssize_t group_show(struct device *dev, struct device_attribute *attr,
2685 char *buf)
2686{
2687 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2688 return gid_valid(tun->group) ?
2689 sysfs_emit(buf, "%u\n",
2690 from_kgid_munged(current_user_ns(), tun->group)) :
2691 sysfs_emit(buf, "-1\n");
2692}
2693
2694static DEVICE_ATTR_RO(tun_flags);
2695static DEVICE_ATTR_RO(owner);
2696static DEVICE_ATTR_RO(group);
2697
2698static struct attribute *tun_dev_attrs[] = {
2699 &dev_attr_tun_flags.attr,
2700 &dev_attr_owner.attr,
2701 &dev_attr_group.attr,
2702 NULL
2703};
2704
2705static const struct attribute_group tun_attr_group = {
2706 .attrs = tun_dev_attrs
2707};
2708
2709static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2710{
2711 struct tun_struct *tun;
2712 struct tun_file *tfile = file->private_data;
2713 struct net_device *dev;
2714 int err;
2715
2716 if (tfile->detached)
2717 return -EINVAL;
2718
2719 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2720 if (!capable(CAP_NET_ADMIN))
2721 return -EPERM;
2722
2723 if (!(ifr->ifr_flags & IFF_NAPI) ||
2724 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2725 return -EINVAL;
2726 }
2727
2728 dev = __dev_get_by_name(net, ifr->ifr_name);
2729 if (dev) {
2730 if (ifr->ifr_flags & IFF_TUN_EXCL)
2731 return -EBUSY;
2732 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2733 tun = netdev_priv(dev);
2734 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2735 tun = netdev_priv(dev);
2736 else
2737 return -EINVAL;
2738
2739 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2740 !!(tun->flags & IFF_MULTI_QUEUE))
2741 return -EINVAL;
2742
2743 if (tun_not_capable(tun))
2744 return -EPERM;
2745 err = security_tun_dev_open(tun->security);
2746 if (err < 0)
2747 return err;
2748
2749 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2750 ifr->ifr_flags & IFF_NAPI,
2751 ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2752 if (err < 0)
2753 return err;
2754
2755 if (tun->flags & IFF_MULTI_QUEUE &&
2756 (tun->numqueues + tun->numdisabled > 1)) {
2757 /* One or more queue has already been attached, no need
2758 * to initialize the device again.
2759 */
2760 netdev_state_change(dev);
2761 return 0;
2762 }
2763
2764 tun->flags = (tun->flags & ~TUN_FEATURES) |
2765 (ifr->ifr_flags & TUN_FEATURES);
2766
2767 netdev_state_change(dev);
2768 } else {
2769 char *name;
2770 unsigned long flags = 0;
2771 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2772 MAX_TAP_QUEUES : 1;
2773
2774 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2775 return -EPERM;
2776 err = security_tun_dev_create();
2777 if (err < 0)
2778 return err;
2779
2780 /* Set dev type */
2781 if (ifr->ifr_flags & IFF_TUN) {
2782 /* TUN device */
2783 flags |= IFF_TUN;
2784 name = "tun%d";
2785 } else if (ifr->ifr_flags & IFF_TAP) {
2786 /* TAP device */
2787 flags |= IFF_TAP;
2788 name = "tap%d";
2789 } else
2790 return -EINVAL;
2791
2792 if (*ifr->ifr_name)
2793 name = ifr->ifr_name;
2794
2795 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2796 NET_NAME_UNKNOWN, tun_setup, queues,
2797 queues);
2798
2799 if (!dev)
2800 return -ENOMEM;
2801
2802 dev_net_set(dev, net);
2803 dev->rtnl_link_ops = &tun_link_ops;
2804 dev->ifindex = tfile->ifindex;
2805 dev->sysfs_groups[0] = &tun_attr_group;
2806
2807 tun = netdev_priv(dev);
2808 tun->dev = dev;
2809 tun->flags = flags;
2810 tun->txflt.count = 0;
2811 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2812
2813 tun->align = NET_SKB_PAD;
2814 tun->filter_attached = false;
2815 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2816 tun->rx_batched = 0;
2817 RCU_INIT_POINTER(tun->steering_prog, NULL);
2818
2819 tun->ifr = ifr;
2820 tun->file = file;
2821
2822 tun_net_initialize(dev);
2823
2824 err = register_netdevice(tun->dev);
2825 if (err < 0) {
2826 free_netdev(dev);
2827 return err;
2828 }
2829 /* free_netdev() won't check refcnt, to avoid race
2830 * with dev_put() we need publish tun after registration.
2831 */
2832 rcu_assign_pointer(tfile->tun, tun);
2833 }
2834
2835 if (ifr->ifr_flags & IFF_NO_CARRIER)
2836 netif_carrier_off(tun->dev);
2837 else
2838 netif_carrier_on(tun->dev);
2839
2840 /* Make sure persistent devices do not get stuck in
2841 * xoff state.
2842 */
2843 if (netif_running(tun->dev))
2844 netif_tx_wake_all_queues(tun->dev);
2845
2846 strcpy(ifr->ifr_name, tun->dev->name);
2847 return 0;
2848}
2849
2850static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2851{
2852 strcpy(ifr->ifr_name, tun->dev->name);
2853
2854 ifr->ifr_flags = tun_flags(tun);
2855
2856}
2857
2858/* This is like a cut-down ethtool ops, except done via tun fd so no
2859 * privs required. */
2860static int set_offload(struct tun_struct *tun, unsigned long arg)
2861{
2862 netdev_features_t features = 0;
2863
2864 if (arg & TUN_F_CSUM) {
2865 features |= NETIF_F_HW_CSUM;
2866 arg &= ~TUN_F_CSUM;
2867
2868 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2869 if (arg & TUN_F_TSO_ECN) {
2870 features |= NETIF_F_TSO_ECN;
2871 arg &= ~TUN_F_TSO_ECN;
2872 }
2873 if (arg & TUN_F_TSO4)
2874 features |= NETIF_F_TSO;
2875 if (arg & TUN_F_TSO6)
2876 features |= NETIF_F_TSO6;
2877 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2878 }
2879
2880 arg &= ~TUN_F_UFO;
2881
2882 /* TODO: for now USO4 and USO6 should work simultaneously */
2883 if (arg & TUN_F_USO4 && arg & TUN_F_USO6) {
2884 features |= NETIF_F_GSO_UDP_L4;
2885 arg &= ~(TUN_F_USO4 | TUN_F_USO6);
2886 }
2887 }
2888
2889 /* This gives the user a way to test for new features in future by
2890 * trying to set them. */
2891 if (arg)
2892 return -EINVAL;
2893
2894 tun->set_features = features;
2895 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2896 tun->dev->wanted_features |= features;
2897 netdev_update_features(tun->dev);
2898
2899 return 0;
2900}
2901
2902static void tun_detach_filter(struct tun_struct *tun, int n)
2903{
2904 int i;
2905 struct tun_file *tfile;
2906
2907 for (i = 0; i < n; i++) {
2908 tfile = rtnl_dereference(tun->tfiles[i]);
2909 lock_sock(tfile->socket.sk);
2910 sk_detach_filter(tfile->socket.sk);
2911 release_sock(tfile->socket.sk);
2912 }
2913
2914 tun->filter_attached = false;
2915}
2916
2917static int tun_attach_filter(struct tun_struct *tun)
2918{
2919 int i, ret = 0;
2920 struct tun_file *tfile;
2921
2922 for (i = 0; i < tun->numqueues; i++) {
2923 tfile = rtnl_dereference(tun->tfiles[i]);
2924 lock_sock(tfile->socket.sk);
2925 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2926 release_sock(tfile->socket.sk);
2927 if (ret) {
2928 tun_detach_filter(tun, i);
2929 return ret;
2930 }
2931 }
2932
2933 tun->filter_attached = true;
2934 return ret;
2935}
2936
2937static void tun_set_sndbuf(struct tun_struct *tun)
2938{
2939 struct tun_file *tfile;
2940 int i;
2941
2942 for (i = 0; i < tun->numqueues; i++) {
2943 tfile = rtnl_dereference(tun->tfiles[i]);
2944 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2945 }
2946}
2947
2948static int tun_set_queue(struct file *file, struct ifreq *ifr)
2949{
2950 struct tun_file *tfile = file->private_data;
2951 struct tun_struct *tun;
2952 int ret = 0;
2953
2954 rtnl_lock();
2955
2956 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2957 tun = tfile->detached;
2958 if (!tun) {
2959 ret = -EINVAL;
2960 goto unlock;
2961 }
2962 ret = security_tun_dev_attach_queue(tun->security);
2963 if (ret < 0)
2964 goto unlock;
2965 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2966 tun->flags & IFF_NAPI_FRAGS, true);
2967 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2968 tun = rtnl_dereference(tfile->tun);
2969 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2970 ret = -EINVAL;
2971 else
2972 __tun_detach(tfile, false);
2973 } else
2974 ret = -EINVAL;
2975
2976 if (ret >= 0)
2977 netdev_state_change(tun->dev);
2978
2979unlock:
2980 rtnl_unlock();
2981 return ret;
2982}
2983
2984static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog __rcu **prog_p,
2985 void __user *data)
2986{
2987 struct bpf_prog *prog;
2988 int fd;
2989
2990 if (copy_from_user(&fd, data, sizeof(fd)))
2991 return -EFAULT;
2992
2993 if (fd == -1) {
2994 prog = NULL;
2995 } else {
2996 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
2997 if (IS_ERR(prog))
2998 return PTR_ERR(prog);
2999 }
3000
3001 return __tun_set_ebpf(tun, prog_p, prog);
3002}
3003
3004/* Return correct value for tun->dev->addr_len based on tun->dev->type. */
3005static unsigned char tun_get_addr_len(unsigned short type)
3006{
3007 switch (type) {
3008 case ARPHRD_IP6GRE:
3009 case ARPHRD_TUNNEL6:
3010 return sizeof(struct in6_addr);
3011 case ARPHRD_IPGRE:
3012 case ARPHRD_TUNNEL:
3013 case ARPHRD_SIT:
3014 return 4;
3015 case ARPHRD_ETHER:
3016 return ETH_ALEN;
3017 case ARPHRD_IEEE802154:
3018 case ARPHRD_IEEE802154_MONITOR:
3019 return IEEE802154_EXTENDED_ADDR_LEN;
3020 case ARPHRD_PHONET_PIPE:
3021 case ARPHRD_PPP:
3022 case ARPHRD_NONE:
3023 return 0;
3024 case ARPHRD_6LOWPAN:
3025 return EUI64_ADDR_LEN;
3026 case ARPHRD_FDDI:
3027 return FDDI_K_ALEN;
3028 case ARPHRD_HIPPI:
3029 return HIPPI_ALEN;
3030 case ARPHRD_IEEE802:
3031 return FC_ALEN;
3032 case ARPHRD_ROSE:
3033 return ROSE_ADDR_LEN;
3034 case ARPHRD_NETROM:
3035 return AX25_ADDR_LEN;
3036 case ARPHRD_LOCALTLK:
3037 return LTALK_ALEN;
3038 default:
3039 return 0;
3040 }
3041}
3042
3043static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
3044 unsigned long arg, int ifreq_len)
3045{
3046 struct tun_file *tfile = file->private_data;
3047 struct net *net = sock_net(&tfile->sk);
3048 struct tun_struct *tun;
3049 void __user* argp = (void __user*)arg;
3050 unsigned int ifindex, carrier;
3051 struct ifreq ifr;
3052 kuid_t owner;
3053 kgid_t group;
3054 int sndbuf;
3055 int vnet_hdr_sz;
3056 int le;
3057 int ret;
3058 bool do_notify = false;
3059
3060 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3061 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3062 if (copy_from_user(&ifr, argp, ifreq_len))
3063 return -EFAULT;
3064 } else {
3065 memset(&ifr, 0, sizeof(ifr));
3066 }
3067 if (cmd == TUNGETFEATURES) {
3068 /* Currently this just means: "what IFF flags are valid?".
3069 * This is needed because we never checked for invalid flags on
3070 * TUNSETIFF.
3071 */
3072 return put_user(IFF_TUN | IFF_TAP | IFF_NO_CARRIER |
3073 TUN_FEATURES, (unsigned int __user*)argp);
3074 } else if (cmd == TUNSETQUEUE) {
3075 return tun_set_queue(file, &ifr);
3076 } else if (cmd == SIOCGSKNS) {
3077 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3078 return -EPERM;
3079 return open_related_ns(&net->ns, get_net_ns);
3080 }
3081
3082 rtnl_lock();
3083
3084 tun = tun_get(tfile);
3085 if (cmd == TUNSETIFF) {
3086 ret = -EEXIST;
3087 if (tun)
3088 goto unlock;
3089
3090 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3091
3092 ret = tun_set_iff(net, file, &ifr);
3093
3094 if (ret)
3095 goto unlock;
3096
3097 if (copy_to_user(argp, &ifr, ifreq_len))
3098 ret = -EFAULT;
3099 goto unlock;
3100 }
3101 if (cmd == TUNSETIFINDEX) {
3102 ret = -EPERM;
3103 if (tun)
3104 goto unlock;
3105
3106 ret = -EFAULT;
3107 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3108 goto unlock;
3109
3110 ret = 0;
3111 tfile->ifindex = ifindex;
3112 goto unlock;
3113 }
3114
3115 ret = -EBADFD;
3116 if (!tun)
3117 goto unlock;
3118
3119 netif_info(tun, drv, tun->dev, "tun_chr_ioctl cmd %u\n", cmd);
3120
3121 net = dev_net(tun->dev);
3122 ret = 0;
3123 switch (cmd) {
3124 case TUNGETIFF:
3125 tun_get_iff(tun, &ifr);
3126
3127 if (tfile->detached)
3128 ifr.ifr_flags |= IFF_DETACH_QUEUE;
3129 if (!tfile->socket.sk->sk_filter)
3130 ifr.ifr_flags |= IFF_NOFILTER;
3131
3132 if (copy_to_user(argp, &ifr, ifreq_len))
3133 ret = -EFAULT;
3134 break;
3135
3136 case TUNSETNOCSUM:
3137 /* Disable/Enable checksum */
3138
3139 /* [unimplemented] */
3140 netif_info(tun, drv, tun->dev, "ignored: set checksum %s\n",
3141 arg ? "disabled" : "enabled");
3142 break;
3143
3144 case TUNSETPERSIST:
3145 /* Disable/Enable persist mode. Keep an extra reference to the
3146 * module to prevent the module being unprobed.
3147 */
3148 if (arg && !(tun->flags & IFF_PERSIST)) {
3149 tun->flags |= IFF_PERSIST;
3150 __module_get(THIS_MODULE);
3151 do_notify = true;
3152 }
3153 if (!arg && (tun->flags & IFF_PERSIST)) {
3154 tun->flags &= ~IFF_PERSIST;
3155 module_put(THIS_MODULE);
3156 do_notify = true;
3157 }
3158
3159 netif_info(tun, drv, tun->dev, "persist %s\n",
3160 arg ? "enabled" : "disabled");
3161 break;
3162
3163 case TUNSETOWNER:
3164 /* Set owner of the device */
3165 owner = make_kuid(current_user_ns(), arg);
3166 if (!uid_valid(owner)) {
3167 ret = -EINVAL;
3168 break;
3169 }
3170 tun->owner = owner;
3171 do_notify = true;
3172 netif_info(tun, drv, tun->dev, "owner set to %u\n",
3173 from_kuid(&init_user_ns, tun->owner));
3174 break;
3175
3176 case TUNSETGROUP:
3177 /* Set group of the device */
3178 group = make_kgid(current_user_ns(), arg);
3179 if (!gid_valid(group)) {
3180 ret = -EINVAL;
3181 break;
3182 }
3183 tun->group = group;
3184 do_notify = true;
3185 netif_info(tun, drv, tun->dev, "group set to %u\n",
3186 from_kgid(&init_user_ns, tun->group));
3187 break;
3188
3189 case TUNSETLINK:
3190 /* Only allow setting the type when the interface is down */
3191 if (tun->dev->flags & IFF_UP) {
3192 netif_info(tun, drv, tun->dev,
3193 "Linktype set failed because interface is up\n");
3194 ret = -EBUSY;
3195 } else {
3196 ret = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE,
3197 tun->dev);
3198 ret = notifier_to_errno(ret);
3199 if (ret) {
3200 netif_info(tun, drv, tun->dev,
3201 "Refused to change device type\n");
3202 break;
3203 }
3204 tun->dev->type = (int) arg;
3205 tun->dev->addr_len = tun_get_addr_len(tun->dev->type);
3206 netif_info(tun, drv, tun->dev, "linktype set to %d\n",
3207 tun->dev->type);
3208 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE,
3209 tun->dev);
3210 }
3211 break;
3212
3213 case TUNSETDEBUG:
3214 tun->msg_enable = (u32)arg;
3215 break;
3216
3217 case TUNSETOFFLOAD:
3218 ret = set_offload(tun, arg);
3219 break;
3220
3221 case TUNSETTXFILTER:
3222 /* Can be set only for TAPs */
3223 ret = -EINVAL;
3224 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3225 break;
3226 ret = update_filter(&tun->txflt, (void __user *)arg);
3227 break;
3228
3229 case SIOCGIFHWADDR:
3230 /* Get hw address */
3231 dev_get_mac_address(&ifr.ifr_hwaddr, net, tun->dev->name);
3232 if (copy_to_user(argp, &ifr, ifreq_len))
3233 ret = -EFAULT;
3234 break;
3235
3236 case SIOCSIFHWADDR:
3237 /* Set hw address */
3238 ret = dev_set_mac_address_user(tun->dev, &ifr.ifr_hwaddr, NULL);
3239 break;
3240
3241 case TUNGETSNDBUF:
3242 sndbuf = tfile->socket.sk->sk_sndbuf;
3243 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3244 ret = -EFAULT;
3245 break;
3246
3247 case TUNSETSNDBUF:
3248 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3249 ret = -EFAULT;
3250 break;
3251 }
3252 if (sndbuf <= 0) {
3253 ret = -EINVAL;
3254 break;
3255 }
3256
3257 tun->sndbuf = sndbuf;
3258 tun_set_sndbuf(tun);
3259 break;
3260
3261 case TUNGETVNETHDRSZ:
3262 vnet_hdr_sz = tun->vnet_hdr_sz;
3263 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3264 ret = -EFAULT;
3265 break;
3266
3267 case TUNSETVNETHDRSZ:
3268 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3269 ret = -EFAULT;
3270 break;
3271 }
3272 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3273 ret = -EINVAL;
3274 break;
3275 }
3276
3277 tun->vnet_hdr_sz = vnet_hdr_sz;
3278 break;
3279
3280 case TUNGETVNETLE:
3281 le = !!(tun->flags & TUN_VNET_LE);
3282 if (put_user(le, (int __user *)argp))
3283 ret = -EFAULT;
3284 break;
3285
3286 case TUNSETVNETLE:
3287 if (get_user(le, (int __user *)argp)) {
3288 ret = -EFAULT;
3289 break;
3290 }
3291 if (le)
3292 tun->flags |= TUN_VNET_LE;
3293 else
3294 tun->flags &= ~TUN_VNET_LE;
3295 break;
3296
3297 case TUNGETVNETBE:
3298 ret = tun_get_vnet_be(tun, argp);
3299 break;
3300
3301 case TUNSETVNETBE:
3302 ret = tun_set_vnet_be(tun, argp);
3303 break;
3304
3305 case TUNATTACHFILTER:
3306 /* Can be set only for TAPs */
3307 ret = -EINVAL;
3308 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3309 break;
3310 ret = -EFAULT;
3311 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3312 break;
3313
3314 ret = tun_attach_filter(tun);
3315 break;
3316
3317 case TUNDETACHFILTER:
3318 /* Can be set only for TAPs */
3319 ret = -EINVAL;
3320 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3321 break;
3322 ret = 0;
3323 tun_detach_filter(tun, tun->numqueues);
3324 break;
3325
3326 case TUNGETFILTER:
3327 ret = -EINVAL;
3328 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3329 break;
3330 ret = -EFAULT;
3331 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3332 break;
3333 ret = 0;
3334 break;
3335
3336 case TUNSETSTEERINGEBPF:
3337 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3338 break;
3339
3340 case TUNSETFILTEREBPF:
3341 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3342 break;
3343
3344 case TUNSETCARRIER:
3345 ret = -EFAULT;
3346 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3347 goto unlock;
3348
3349 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3350 break;
3351
3352 case TUNGETDEVNETNS:
3353 ret = -EPERM;
3354 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3355 goto unlock;
3356 ret = open_related_ns(&net->ns, get_net_ns);
3357 break;
3358
3359 default:
3360 ret = -EINVAL;
3361 break;
3362 }
3363
3364 if (do_notify)
3365 netdev_state_change(tun->dev);
3366
3367unlock:
3368 rtnl_unlock();
3369 if (tun)
3370 tun_put(tun);
3371 return ret;
3372}
3373
3374static long tun_chr_ioctl(struct file *file,
3375 unsigned int cmd, unsigned long arg)
3376{
3377 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3378}
3379
3380#ifdef CONFIG_COMPAT
3381static long tun_chr_compat_ioctl(struct file *file,
3382 unsigned int cmd, unsigned long arg)
3383{
3384 switch (cmd) {
3385 case TUNSETIFF:
3386 case TUNGETIFF:
3387 case TUNSETTXFILTER:
3388 case TUNGETSNDBUF:
3389 case TUNSETSNDBUF:
3390 case SIOCGIFHWADDR:
3391 case SIOCSIFHWADDR:
3392 arg = (unsigned long)compat_ptr(arg);
3393 break;
3394 default:
3395 arg = (compat_ulong_t)arg;
3396 break;
3397 }
3398
3399 /*
3400 * compat_ifreq is shorter than ifreq, so we must not access beyond
3401 * the end of that structure. All fields that are used in this
3402 * driver are compatible though, we don't need to convert the
3403 * contents.
3404 */
3405 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3406}
3407#endif /* CONFIG_COMPAT */
3408
3409static int tun_chr_fasync(int fd, struct file *file, int on)
3410{
3411 struct tun_file *tfile = file->private_data;
3412 int ret;
3413
3414 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3415 goto out;
3416
3417 if (on) {
3418 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3419 tfile->flags |= TUN_FASYNC;
3420 } else
3421 tfile->flags &= ~TUN_FASYNC;
3422 ret = 0;
3423out:
3424 return ret;
3425}
3426
3427static int tun_chr_open(struct inode *inode, struct file * file)
3428{
3429 struct net *net = current->nsproxy->net_ns;
3430 struct tun_file *tfile;
3431
3432 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3433 &tun_proto, 0);
3434 if (!tfile)
3435 return -ENOMEM;
3436 if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3437 sk_free(&tfile->sk);
3438 return -ENOMEM;
3439 }
3440
3441 mutex_init(&tfile->napi_mutex);
3442 RCU_INIT_POINTER(tfile->tun, NULL);
3443 tfile->flags = 0;
3444 tfile->ifindex = 0;
3445
3446 init_waitqueue_head(&tfile->socket.wq.wait);
3447
3448 tfile->socket.file = file;
3449 tfile->socket.ops = &tun_socket_ops;
3450
3451 sock_init_data(&tfile->socket, &tfile->sk);
3452
3453 tfile->sk.sk_write_space = tun_sock_write_space;
3454 tfile->sk.sk_sndbuf = INT_MAX;
3455
3456 file->private_data = tfile;
3457 INIT_LIST_HEAD(&tfile->next);
3458
3459 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3460
3461 return 0;
3462}
3463
3464static int tun_chr_close(struct inode *inode, struct file *file)
3465{
3466 struct tun_file *tfile = file->private_data;
3467
3468 tun_detach(tfile, true);
3469
3470 return 0;
3471}
3472
3473#ifdef CONFIG_PROC_FS
3474static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3475{
3476 struct tun_file *tfile = file->private_data;
3477 struct tun_struct *tun;
3478 struct ifreq ifr;
3479
3480 memset(&ifr, 0, sizeof(ifr));
3481
3482 rtnl_lock();
3483 tun = tun_get(tfile);
3484 if (tun)
3485 tun_get_iff(tun, &ifr);
3486 rtnl_unlock();
3487
3488 if (tun)
3489 tun_put(tun);
3490
3491 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3492}
3493#endif
3494
3495static const struct file_operations tun_fops = {
3496 .owner = THIS_MODULE,
3497 .llseek = no_llseek,
3498 .read_iter = tun_chr_read_iter,
3499 .write_iter = tun_chr_write_iter,
3500 .poll = tun_chr_poll,
3501 .unlocked_ioctl = tun_chr_ioctl,
3502#ifdef CONFIG_COMPAT
3503 .compat_ioctl = tun_chr_compat_ioctl,
3504#endif
3505 .open = tun_chr_open,
3506 .release = tun_chr_close,
3507 .fasync = tun_chr_fasync,
3508#ifdef CONFIG_PROC_FS
3509 .show_fdinfo = tun_chr_show_fdinfo,
3510#endif
3511};
3512
3513static struct miscdevice tun_miscdev = {
3514 .minor = TUN_MINOR,
3515 .name = "tun",
3516 .nodename = "net/tun",
3517 .fops = &tun_fops,
3518};
3519
3520/* ethtool interface */
3521
3522static void tun_default_link_ksettings(struct net_device *dev,
3523 struct ethtool_link_ksettings *cmd)
3524{
3525 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3526 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3527 cmd->base.speed = SPEED_10000;
3528 cmd->base.duplex = DUPLEX_FULL;
3529 cmd->base.port = PORT_TP;
3530 cmd->base.phy_address = 0;
3531 cmd->base.autoneg = AUTONEG_DISABLE;
3532}
3533
3534static int tun_get_link_ksettings(struct net_device *dev,
3535 struct ethtool_link_ksettings *cmd)
3536{
3537 struct tun_struct *tun = netdev_priv(dev);
3538
3539 memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3540 return 0;
3541}
3542
3543static int tun_set_link_ksettings(struct net_device *dev,
3544 const struct ethtool_link_ksettings *cmd)
3545{
3546 struct tun_struct *tun = netdev_priv(dev);
3547
3548 memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3549 return 0;
3550}
3551
3552static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3553{
3554 struct tun_struct *tun = netdev_priv(dev);
3555
3556 strscpy(info->driver, DRV_NAME, sizeof(info->driver));
3557 strscpy(info->version, DRV_VERSION, sizeof(info->version));
3558
3559 switch (tun->flags & TUN_TYPE_MASK) {
3560 case IFF_TUN:
3561 strscpy(info->bus_info, "tun", sizeof(info->bus_info));
3562 break;
3563 case IFF_TAP:
3564 strscpy(info->bus_info, "tap", sizeof(info->bus_info));
3565 break;
3566 }
3567}
3568
3569static u32 tun_get_msglevel(struct net_device *dev)
3570{
3571 struct tun_struct *tun = netdev_priv(dev);
3572
3573 return tun->msg_enable;
3574}
3575
3576static void tun_set_msglevel(struct net_device *dev, u32 value)
3577{
3578 struct tun_struct *tun = netdev_priv(dev);
3579
3580 tun->msg_enable = value;
3581}
3582
3583static int tun_get_coalesce(struct net_device *dev,
3584 struct ethtool_coalesce *ec,
3585 struct kernel_ethtool_coalesce *kernel_coal,
3586 struct netlink_ext_ack *extack)
3587{
3588 struct tun_struct *tun = netdev_priv(dev);
3589
3590 ec->rx_max_coalesced_frames = tun->rx_batched;
3591
3592 return 0;
3593}
3594
3595static int tun_set_coalesce(struct net_device *dev,
3596 struct ethtool_coalesce *ec,
3597 struct kernel_ethtool_coalesce *kernel_coal,
3598 struct netlink_ext_ack *extack)
3599{
3600 struct tun_struct *tun = netdev_priv(dev);
3601
3602 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3603 tun->rx_batched = NAPI_POLL_WEIGHT;
3604 else
3605 tun->rx_batched = ec->rx_max_coalesced_frames;
3606
3607 return 0;
3608}
3609
3610static const struct ethtool_ops tun_ethtool_ops = {
3611 .supported_coalesce_params = ETHTOOL_COALESCE_RX_MAX_FRAMES,
3612 .get_drvinfo = tun_get_drvinfo,
3613 .get_msglevel = tun_get_msglevel,
3614 .set_msglevel = tun_set_msglevel,
3615 .get_link = ethtool_op_get_link,
3616 .get_ts_info = ethtool_op_get_ts_info,
3617 .get_coalesce = tun_get_coalesce,
3618 .set_coalesce = tun_set_coalesce,
3619 .get_link_ksettings = tun_get_link_ksettings,
3620 .set_link_ksettings = tun_set_link_ksettings,
3621};
3622
3623static int tun_queue_resize(struct tun_struct *tun)
3624{
3625 struct net_device *dev = tun->dev;
3626 struct tun_file *tfile;
3627 struct ptr_ring **rings;
3628 int n = tun->numqueues + tun->numdisabled;
3629 int ret, i;
3630
3631 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3632 if (!rings)
3633 return -ENOMEM;
3634
3635 for (i = 0; i < tun->numqueues; i++) {
3636 tfile = rtnl_dereference(tun->tfiles[i]);
3637 rings[i] = &tfile->tx_ring;
3638 }
3639 list_for_each_entry(tfile, &tun->disabled, next)
3640 rings[i++] = &tfile->tx_ring;
3641
3642 ret = ptr_ring_resize_multiple(rings, n,
3643 dev->tx_queue_len, GFP_KERNEL,
3644 tun_ptr_free);
3645
3646 kfree(rings);
3647 return ret;
3648}
3649
3650static int tun_device_event(struct notifier_block *unused,
3651 unsigned long event, void *ptr)
3652{
3653 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3654 struct tun_struct *tun = netdev_priv(dev);
3655 int i;
3656
3657 if (dev->rtnl_link_ops != &tun_link_ops)
3658 return NOTIFY_DONE;
3659
3660 switch (event) {
3661 case NETDEV_CHANGE_TX_QUEUE_LEN:
3662 if (tun_queue_resize(tun))
3663 return NOTIFY_BAD;
3664 break;
3665 case NETDEV_UP:
3666 for (i = 0; i < tun->numqueues; i++) {
3667 struct tun_file *tfile;
3668
3669 tfile = rtnl_dereference(tun->tfiles[i]);
3670 tfile->socket.sk->sk_write_space(tfile->socket.sk);
3671 }
3672 break;
3673 default:
3674 break;
3675 }
3676
3677 return NOTIFY_DONE;
3678}
3679
3680static struct notifier_block tun_notifier_block __read_mostly = {
3681 .notifier_call = tun_device_event,
3682};
3683
3684static int __init tun_init(void)
3685{
3686 int ret = 0;
3687
3688 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3689
3690 ret = rtnl_link_register(&tun_link_ops);
3691 if (ret) {
3692 pr_err("Can't register link_ops\n");
3693 goto err_linkops;
3694 }
3695
3696 ret = misc_register(&tun_miscdev);
3697 if (ret) {
3698 pr_err("Can't register misc device %d\n", TUN_MINOR);
3699 goto err_misc;
3700 }
3701
3702 ret = register_netdevice_notifier(&tun_notifier_block);
3703 if (ret) {
3704 pr_err("Can't register netdevice notifier\n");
3705 goto err_notifier;
3706 }
3707
3708 return 0;
3709
3710err_notifier:
3711 misc_deregister(&tun_miscdev);
3712err_misc:
3713 rtnl_link_unregister(&tun_link_ops);
3714err_linkops:
3715 return ret;
3716}
3717
3718static void tun_cleanup(void)
3719{
3720 misc_deregister(&tun_miscdev);
3721 rtnl_link_unregister(&tun_link_ops);
3722 unregister_netdevice_notifier(&tun_notifier_block);
3723}
3724
3725/* Get an underlying socket object from tun file. Returns error unless file is
3726 * attached to a device. The returned object works like a packet socket, it
3727 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3728 * holding a reference to the file for as long as the socket is in use. */
3729struct socket *tun_get_socket(struct file *file)
3730{
3731 struct tun_file *tfile;
3732 if (file->f_op != &tun_fops)
3733 return ERR_PTR(-EINVAL);
3734 tfile = file->private_data;
3735 if (!tfile)
3736 return ERR_PTR(-EBADFD);
3737 return &tfile->socket;
3738}
3739EXPORT_SYMBOL_GPL(tun_get_socket);
3740
3741struct ptr_ring *tun_get_tx_ring(struct file *file)
3742{
3743 struct tun_file *tfile;
3744
3745 if (file->f_op != &tun_fops)
3746 return ERR_PTR(-EINVAL);
3747 tfile = file->private_data;
3748 if (!tfile)
3749 return ERR_PTR(-EBADFD);
3750 return &tfile->tx_ring;
3751}
3752EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3753
3754module_init(tun_init);
3755module_exit(tun_cleanup);
3756MODULE_DESCRIPTION(DRV_DESCRIPTION);
3757MODULE_AUTHOR(DRV_COPYRIGHT);
3758MODULE_LICENSE("GPL");
3759MODULE_ALIAS_MISCDEV(TUN_MINOR);
3760MODULE_ALIAS("devname:net/tun");