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1/*
2 * TUN - Universal TUN/TAP device driver.
3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
16 */
17
18/*
19 * Changes:
20 *
21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
22 * Add TUNSETLINK ioctl to set the link encapsulation
23 *
24 * Mark Smith <markzzzsmith@yahoo.com.au>
25 * Use eth_random_addr() for tap MAC address.
26 *
27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
28 * Fixes in packet dropping, queue length setting and queue wakeup.
29 * Increased default tx queue length.
30 * Added ethtool API.
31 * Minor cleanups
32 *
33 * Daniel Podlejski <underley@underley.eu.org>
34 * Modifications for 2.3.99-pre5 kernel.
35 */
36
37#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
38
39#define DRV_NAME "tun"
40#define DRV_VERSION "1.6"
41#define DRV_DESCRIPTION "Universal TUN/TAP device driver"
42#define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
43
44#include <linux/module.h>
45#include <linux/errno.h>
46#include <linux/kernel.h>
47#include <linux/sched/signal.h>
48#include <linux/major.h>
49#include <linux/slab.h>
50#include <linux/poll.h>
51#include <linux/fcntl.h>
52#include <linux/init.h>
53#include <linux/skbuff.h>
54#include <linux/netdevice.h>
55#include <linux/etherdevice.h>
56#include <linux/miscdevice.h>
57#include <linux/ethtool.h>
58#include <linux/rtnetlink.h>
59#include <linux/compat.h>
60#include <linux/if.h>
61#include <linux/if_arp.h>
62#include <linux/if_ether.h>
63#include <linux/if_tun.h>
64#include <linux/if_vlan.h>
65#include <linux/crc32.h>
66#include <linux/nsproxy.h>
67#include <linux/virtio_net.h>
68#include <linux/rcupdate.h>
69#include <net/net_namespace.h>
70#include <net/netns/generic.h>
71#include <net/rtnetlink.h>
72#include <net/sock.h>
73#include <linux/seq_file.h>
74#include <linux/uio.h>
75#include <linux/skb_array.h>
76#include <linux/bpf.h>
77#include <linux/bpf_trace.h>
78#include <linux/mutex.h>
79
80#include <linux/uaccess.h>
81#include <linux/proc_fs.h>
82
83/* Uncomment to enable debugging */
84/* #define TUN_DEBUG 1 */
85
86#ifdef TUN_DEBUG
87static int debug;
88
89#define tun_debug(level, tun, fmt, args...) \
90do { \
91 if (tun->debug) \
92 netdev_printk(level, tun->dev, fmt, ##args); \
93} while (0)
94#define DBG1(level, fmt, args...) \
95do { \
96 if (debug == 2) \
97 printk(level fmt, ##args); \
98} while (0)
99#else
100#define tun_debug(level, tun, fmt, args...) \
101do { \
102 if (0) \
103 netdev_printk(level, tun->dev, fmt, ##args); \
104} while (0)
105#define DBG1(level, fmt, args...) \
106do { \
107 if (0) \
108 printk(level fmt, ##args); \
109} while (0)
110#endif
111
112#define TUN_HEADROOM 256
113#define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
114
115/* TUN device flags */
116
117/* IFF_ATTACH_QUEUE is never stored in device flags,
118 * overload it to mean fasync when stored there.
119 */
120#define TUN_FASYNC IFF_ATTACH_QUEUE
121/* High bits in flags field are unused. */
122#define TUN_VNET_LE 0x80000000
123#define TUN_VNET_BE 0x40000000
124
125#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
126 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
127
128#define GOODCOPY_LEN 128
129
130#define FLT_EXACT_COUNT 8
131struct tap_filter {
132 unsigned int count; /* Number of addrs. Zero means disabled */
133 u32 mask[2]; /* Mask of the hashed addrs */
134 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
135};
136
137/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
138 * to max number of VCPUs in guest. */
139#define MAX_TAP_QUEUES 256
140#define MAX_TAP_FLOWS 4096
141
142#define TUN_FLOW_EXPIRE (3 * HZ)
143
144struct tun_pcpu_stats {
145 u64 rx_packets;
146 u64 rx_bytes;
147 u64 tx_packets;
148 u64 tx_bytes;
149 struct u64_stats_sync syncp;
150 u32 rx_dropped;
151 u32 tx_dropped;
152 u32 rx_frame_errors;
153};
154
155/* A tun_file connects an open character device to a tuntap netdevice. It
156 * also contains all socket related structures (except sock_fprog and tap_filter)
157 * to serve as one transmit queue for tuntap device. The sock_fprog and
158 * tap_filter were kept in tun_struct since they were used for filtering for the
159 * netdevice not for a specific queue (at least I didn't see the requirement for
160 * this).
161 *
162 * RCU usage:
163 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
164 * other can only be read while rcu_read_lock or rtnl_lock is held.
165 */
166struct tun_file {
167 struct sock sk;
168 struct socket socket;
169 struct socket_wq wq;
170 struct tun_struct __rcu *tun;
171 struct fasync_struct *fasync;
172 /* only used for fasnyc */
173 unsigned int flags;
174 union {
175 u16 queue_index;
176 unsigned int ifindex;
177 };
178 struct napi_struct napi;
179 bool napi_enabled;
180 struct mutex napi_mutex; /* Protects access to the above napi */
181 struct list_head next;
182 struct tun_struct *detached;
183 struct ptr_ring tx_ring;
184 struct xdp_rxq_info xdp_rxq;
185};
186
187struct tun_flow_entry {
188 struct hlist_node hash_link;
189 struct rcu_head rcu;
190 struct tun_struct *tun;
191
192 u32 rxhash;
193 u32 rps_rxhash;
194 int queue_index;
195 unsigned long updated;
196};
197
198#define TUN_NUM_FLOW_ENTRIES 1024
199
200struct tun_prog {
201 struct rcu_head rcu;
202 struct bpf_prog *prog;
203};
204
205/* Since the socket were moved to tun_file, to preserve the behavior of persist
206 * device, socket filter, sndbuf and vnet header size were restore when the
207 * file were attached to a persist device.
208 */
209struct tun_struct {
210 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
211 unsigned int numqueues;
212 unsigned int flags;
213 kuid_t owner;
214 kgid_t group;
215
216 struct net_device *dev;
217 netdev_features_t set_features;
218#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
219 NETIF_F_TSO6)
220
221 int align;
222 int vnet_hdr_sz;
223 int sndbuf;
224 struct tap_filter txflt;
225 struct sock_fprog fprog;
226 /* protected by rtnl lock */
227 bool filter_attached;
228#ifdef TUN_DEBUG
229 int debug;
230#endif
231 spinlock_t lock;
232 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
233 struct timer_list flow_gc_timer;
234 unsigned long ageing_time;
235 unsigned int numdisabled;
236 struct list_head disabled;
237 void *security;
238 u32 flow_count;
239 u32 rx_batched;
240 struct tun_pcpu_stats __percpu *pcpu_stats;
241 struct bpf_prog __rcu *xdp_prog;
242 struct tun_prog __rcu *steering_prog;
243 struct tun_prog __rcu *filter_prog;
244};
245
246struct veth {
247 __be16 h_vlan_proto;
248 __be16 h_vlan_TCI;
249};
250
251bool tun_is_xdp_buff(void *ptr)
252{
253 return (unsigned long)ptr & TUN_XDP_FLAG;
254}
255EXPORT_SYMBOL(tun_is_xdp_buff);
256
257void *tun_xdp_to_ptr(void *ptr)
258{
259 return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
260}
261EXPORT_SYMBOL(tun_xdp_to_ptr);
262
263void *tun_ptr_to_xdp(void *ptr)
264{
265 return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
266}
267EXPORT_SYMBOL(tun_ptr_to_xdp);
268
269static int tun_napi_receive(struct napi_struct *napi, int budget)
270{
271 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
272 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
273 struct sk_buff_head process_queue;
274 struct sk_buff *skb;
275 int received = 0;
276
277 __skb_queue_head_init(&process_queue);
278
279 spin_lock(&queue->lock);
280 skb_queue_splice_tail_init(queue, &process_queue);
281 spin_unlock(&queue->lock);
282
283 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
284 napi_gro_receive(napi, skb);
285 ++received;
286 }
287
288 if (!skb_queue_empty(&process_queue)) {
289 spin_lock(&queue->lock);
290 skb_queue_splice(&process_queue, queue);
291 spin_unlock(&queue->lock);
292 }
293
294 return received;
295}
296
297static int tun_napi_poll(struct napi_struct *napi, int budget)
298{
299 unsigned int received;
300
301 received = tun_napi_receive(napi, budget);
302
303 if (received < budget)
304 napi_complete_done(napi, received);
305
306 return received;
307}
308
309static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
310 bool napi_en)
311{
312 tfile->napi_enabled = napi_en;
313 if (napi_en) {
314 netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
315 NAPI_POLL_WEIGHT);
316 napi_enable(&tfile->napi);
317 mutex_init(&tfile->napi_mutex);
318 }
319}
320
321static void tun_napi_disable(struct tun_struct *tun, struct tun_file *tfile)
322{
323 if (tfile->napi_enabled)
324 napi_disable(&tfile->napi);
325}
326
327static void tun_napi_del(struct tun_struct *tun, struct tun_file *tfile)
328{
329 if (tfile->napi_enabled)
330 netif_napi_del(&tfile->napi);
331}
332
333static bool tun_napi_frags_enabled(const struct tun_struct *tun)
334{
335 return READ_ONCE(tun->flags) & IFF_NAPI_FRAGS;
336}
337
338#ifdef CONFIG_TUN_VNET_CROSS_LE
339static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
340{
341 return tun->flags & TUN_VNET_BE ? false :
342 virtio_legacy_is_little_endian();
343}
344
345static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
346{
347 int be = !!(tun->flags & TUN_VNET_BE);
348
349 if (put_user(be, argp))
350 return -EFAULT;
351
352 return 0;
353}
354
355static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
356{
357 int be;
358
359 if (get_user(be, argp))
360 return -EFAULT;
361
362 if (be)
363 tun->flags |= TUN_VNET_BE;
364 else
365 tun->flags &= ~TUN_VNET_BE;
366
367 return 0;
368}
369#else
370static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
371{
372 return virtio_legacy_is_little_endian();
373}
374
375static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
376{
377 return -EINVAL;
378}
379
380static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
381{
382 return -EINVAL;
383}
384#endif /* CONFIG_TUN_VNET_CROSS_LE */
385
386static inline bool tun_is_little_endian(struct tun_struct *tun)
387{
388 return tun->flags & TUN_VNET_LE ||
389 tun_legacy_is_little_endian(tun);
390}
391
392static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
393{
394 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
395}
396
397static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
398{
399 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
400}
401
402static inline u32 tun_hashfn(u32 rxhash)
403{
404 return rxhash & 0x3ff;
405}
406
407static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
408{
409 struct tun_flow_entry *e;
410
411 hlist_for_each_entry_rcu(e, head, hash_link) {
412 if (e->rxhash == rxhash)
413 return e;
414 }
415 return NULL;
416}
417
418static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
419 struct hlist_head *head,
420 u32 rxhash, u16 queue_index)
421{
422 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
423
424 if (e) {
425 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
426 rxhash, queue_index);
427 e->updated = jiffies;
428 e->rxhash = rxhash;
429 e->rps_rxhash = 0;
430 e->queue_index = queue_index;
431 e->tun = tun;
432 hlist_add_head_rcu(&e->hash_link, head);
433 ++tun->flow_count;
434 }
435 return e;
436}
437
438static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
439{
440 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
441 e->rxhash, e->queue_index);
442 hlist_del_rcu(&e->hash_link);
443 kfree_rcu(e, rcu);
444 --tun->flow_count;
445}
446
447static void tun_flow_flush(struct tun_struct *tun)
448{
449 int i;
450
451 spin_lock_bh(&tun->lock);
452 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
453 struct tun_flow_entry *e;
454 struct hlist_node *n;
455
456 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
457 tun_flow_delete(tun, e);
458 }
459 spin_unlock_bh(&tun->lock);
460}
461
462static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
463{
464 int i;
465
466 spin_lock_bh(&tun->lock);
467 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
468 struct tun_flow_entry *e;
469 struct hlist_node *n;
470
471 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
472 if (e->queue_index == queue_index)
473 tun_flow_delete(tun, e);
474 }
475 }
476 spin_unlock_bh(&tun->lock);
477}
478
479static void tun_flow_cleanup(struct timer_list *t)
480{
481 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
482 unsigned long delay = tun->ageing_time;
483 unsigned long next_timer = jiffies + delay;
484 unsigned long count = 0;
485 int i;
486
487 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
488
489 spin_lock(&tun->lock);
490 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
491 struct tun_flow_entry *e;
492 struct hlist_node *n;
493
494 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
495 unsigned long this_timer;
496
497 this_timer = e->updated + delay;
498 if (time_before_eq(this_timer, jiffies)) {
499 tun_flow_delete(tun, e);
500 continue;
501 }
502 count++;
503 if (time_before(this_timer, next_timer))
504 next_timer = this_timer;
505 }
506 }
507
508 if (count)
509 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
510 spin_unlock(&tun->lock);
511}
512
513static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
514 struct tun_file *tfile)
515{
516 struct hlist_head *head;
517 struct tun_flow_entry *e;
518 unsigned long delay = tun->ageing_time;
519 u16 queue_index = tfile->queue_index;
520
521 if (!rxhash)
522 return;
523 else
524 head = &tun->flows[tun_hashfn(rxhash)];
525
526 rcu_read_lock();
527
528 /* We may get a very small possibility of OOO during switching, not
529 * worth to optimize.*/
530 if (tun->numqueues == 1 || tfile->detached)
531 goto unlock;
532
533 e = tun_flow_find(head, rxhash);
534 if (likely(e)) {
535 /* TODO: keep queueing to old queue until it's empty? */
536 e->queue_index = queue_index;
537 e->updated = jiffies;
538 sock_rps_record_flow_hash(e->rps_rxhash);
539 } else {
540 spin_lock_bh(&tun->lock);
541 if (!tun_flow_find(head, rxhash) &&
542 tun->flow_count < MAX_TAP_FLOWS)
543 tun_flow_create(tun, head, rxhash, queue_index);
544
545 if (!timer_pending(&tun->flow_gc_timer))
546 mod_timer(&tun->flow_gc_timer,
547 round_jiffies_up(jiffies + delay));
548 spin_unlock_bh(&tun->lock);
549 }
550
551unlock:
552 rcu_read_unlock();
553}
554
555/**
556 * Save the hash received in the stack receive path and update the
557 * flow_hash table accordingly.
558 */
559static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
560{
561 if (unlikely(e->rps_rxhash != hash))
562 e->rps_rxhash = hash;
563}
564
565/* We try to identify a flow through its rxhash first. The reason that
566 * we do not check rxq no. is because some cards(e.g 82599), chooses
567 * the rxq based on the txq where the last packet of the flow comes. As
568 * the userspace application move between processors, we may get a
569 * different rxq no. here. If we could not get rxhash, then we would
570 * hope the rxq no. may help here.
571 */
572static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
573{
574 struct tun_flow_entry *e;
575 u32 txq = 0;
576 u32 numqueues = 0;
577
578 numqueues = READ_ONCE(tun->numqueues);
579
580 txq = __skb_get_hash_symmetric(skb);
581 if (txq) {
582 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
583 if (e) {
584 tun_flow_save_rps_rxhash(e, txq);
585 txq = e->queue_index;
586 } else
587 /* use multiply and shift instead of expensive divide */
588 txq = ((u64)txq * numqueues) >> 32;
589 } else if (likely(skb_rx_queue_recorded(skb))) {
590 txq = skb_get_rx_queue(skb);
591 while (unlikely(txq >= numqueues))
592 txq -= numqueues;
593 }
594
595 return txq;
596}
597
598static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
599{
600 struct tun_prog *prog;
601 u16 ret = 0;
602
603 prog = rcu_dereference(tun->steering_prog);
604 if (prog)
605 ret = bpf_prog_run_clear_cb(prog->prog, skb);
606
607 return ret % tun->numqueues;
608}
609
610static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
611 void *accel_priv, select_queue_fallback_t fallback)
612{
613 struct tun_struct *tun = netdev_priv(dev);
614 u16 ret;
615
616 rcu_read_lock();
617 if (rcu_dereference(tun->steering_prog))
618 ret = tun_ebpf_select_queue(tun, skb);
619 else
620 ret = tun_automq_select_queue(tun, skb);
621 rcu_read_unlock();
622
623 return ret;
624}
625
626static inline bool tun_not_capable(struct tun_struct *tun)
627{
628 const struct cred *cred = current_cred();
629 struct net *net = dev_net(tun->dev);
630
631 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
632 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
633 !ns_capable(net->user_ns, CAP_NET_ADMIN);
634}
635
636static void tun_set_real_num_queues(struct tun_struct *tun)
637{
638 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
639 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
640}
641
642static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
643{
644 tfile->detached = tun;
645 list_add_tail(&tfile->next, &tun->disabled);
646 ++tun->numdisabled;
647}
648
649static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
650{
651 struct tun_struct *tun = tfile->detached;
652
653 tfile->detached = NULL;
654 list_del_init(&tfile->next);
655 --tun->numdisabled;
656 return tun;
657}
658
659void tun_ptr_free(void *ptr)
660{
661 if (!ptr)
662 return;
663 if (tun_is_xdp_buff(ptr)) {
664 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
665
666 put_page(virt_to_head_page(xdp->data));
667 } else {
668 __skb_array_destroy_skb(ptr);
669 }
670}
671EXPORT_SYMBOL_GPL(tun_ptr_free);
672
673static void tun_queue_purge(struct tun_file *tfile)
674{
675 void *ptr;
676
677 while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
678 tun_ptr_free(ptr);
679
680 skb_queue_purge(&tfile->sk.sk_write_queue);
681 skb_queue_purge(&tfile->sk.sk_error_queue);
682}
683
684static void __tun_detach(struct tun_file *tfile, bool clean)
685{
686 struct tun_file *ntfile;
687 struct tun_struct *tun;
688
689 tun = rtnl_dereference(tfile->tun);
690
691 if (tun && clean) {
692 tun_napi_disable(tun, tfile);
693 tun_napi_del(tun, tfile);
694 }
695
696 if (tun && !tfile->detached) {
697 u16 index = tfile->queue_index;
698 BUG_ON(index >= tun->numqueues);
699
700 rcu_assign_pointer(tun->tfiles[index],
701 tun->tfiles[tun->numqueues - 1]);
702 ntfile = rtnl_dereference(tun->tfiles[index]);
703 ntfile->queue_index = index;
704
705 --tun->numqueues;
706 if (clean) {
707 RCU_INIT_POINTER(tfile->tun, NULL);
708 sock_put(&tfile->sk);
709 } else
710 tun_disable_queue(tun, tfile);
711
712 synchronize_net();
713 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
714 /* Drop read queue */
715 tun_queue_purge(tfile);
716 tun_set_real_num_queues(tun);
717 } else if (tfile->detached && clean) {
718 tun = tun_enable_queue(tfile);
719 sock_put(&tfile->sk);
720 }
721
722 if (clean) {
723 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
724 netif_carrier_off(tun->dev);
725
726 if (!(tun->flags & IFF_PERSIST) &&
727 tun->dev->reg_state == NETREG_REGISTERED)
728 unregister_netdevice(tun->dev);
729 }
730 if (tun)
731 xdp_rxq_info_unreg(&tfile->xdp_rxq);
732 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
733 sock_put(&tfile->sk);
734 }
735}
736
737static void tun_detach(struct tun_file *tfile, bool clean)
738{
739 struct tun_struct *tun;
740 struct net_device *dev;
741
742 rtnl_lock();
743 tun = rtnl_dereference(tfile->tun);
744 dev = tun ? tun->dev : NULL;
745 __tun_detach(tfile, clean);
746 if (dev)
747 netdev_state_change(dev);
748 rtnl_unlock();
749}
750
751static void tun_detach_all(struct net_device *dev)
752{
753 struct tun_struct *tun = netdev_priv(dev);
754 struct tun_file *tfile, *tmp;
755 int i, n = tun->numqueues;
756
757 for (i = 0; i < n; i++) {
758 tfile = rtnl_dereference(tun->tfiles[i]);
759 BUG_ON(!tfile);
760 tun_napi_disable(tun, tfile);
761 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
762 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
763 RCU_INIT_POINTER(tfile->tun, NULL);
764 --tun->numqueues;
765 }
766 list_for_each_entry(tfile, &tun->disabled, next) {
767 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
768 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
769 RCU_INIT_POINTER(tfile->tun, NULL);
770 }
771 BUG_ON(tun->numqueues != 0);
772
773 synchronize_net();
774 for (i = 0; i < n; i++) {
775 tfile = rtnl_dereference(tun->tfiles[i]);
776 tun_napi_del(tun, tfile);
777 /* Drop read queue */
778 tun_queue_purge(tfile);
779 xdp_rxq_info_unreg(&tfile->xdp_rxq);
780 sock_put(&tfile->sk);
781 }
782 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
783 tun_enable_queue(tfile);
784 tun_queue_purge(tfile);
785 xdp_rxq_info_unreg(&tfile->xdp_rxq);
786 sock_put(&tfile->sk);
787 }
788 BUG_ON(tun->numdisabled != 0);
789
790 if (tun->flags & IFF_PERSIST)
791 module_put(THIS_MODULE);
792}
793
794static int tun_attach(struct tun_struct *tun, struct file *file,
795 bool skip_filter, bool napi)
796{
797 struct tun_file *tfile = file->private_data;
798 struct net_device *dev = tun->dev;
799 int err;
800
801 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
802 if (err < 0)
803 goto out;
804
805 err = -EINVAL;
806 if (rtnl_dereference(tfile->tun) && !tfile->detached)
807 goto out;
808
809 err = -EBUSY;
810 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
811 goto out;
812
813 err = -E2BIG;
814 if (!tfile->detached &&
815 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
816 goto out;
817
818 err = 0;
819
820 /* Re-attach the filter to persist device */
821 if (!skip_filter && (tun->filter_attached == true)) {
822 lock_sock(tfile->socket.sk);
823 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
824 release_sock(tfile->socket.sk);
825 if (!err)
826 goto out;
827 }
828
829 if (!tfile->detached &&
830 ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
831 GFP_KERNEL, tun_ptr_free)) {
832 err = -ENOMEM;
833 goto out;
834 }
835
836 tfile->queue_index = tun->numqueues;
837 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
838
839 if (tfile->detached) {
840 /* Re-attach detached tfile, updating XDP queue_index */
841 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
842
843 if (tfile->xdp_rxq.queue_index != tfile->queue_index)
844 tfile->xdp_rxq.queue_index = tfile->queue_index;
845 } else {
846 /* Setup XDP RX-queue info, for new tfile getting attached */
847 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
848 tun->dev, tfile->queue_index);
849 if (err < 0)
850 goto out;
851 err = 0;
852 }
853
854 rcu_assign_pointer(tfile->tun, tun);
855 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
856 tun->numqueues++;
857
858 if (tfile->detached) {
859 tun_enable_queue(tfile);
860 } else {
861 sock_hold(&tfile->sk);
862 tun_napi_init(tun, tfile, napi);
863 }
864
865 tun_set_real_num_queues(tun);
866
867 /* device is allowed to go away first, so no need to hold extra
868 * refcnt.
869 */
870
871out:
872 return err;
873}
874
875static struct tun_struct *tun_get(struct tun_file *tfile)
876{
877 struct tun_struct *tun;
878
879 rcu_read_lock();
880 tun = rcu_dereference(tfile->tun);
881 if (tun)
882 dev_hold(tun->dev);
883 rcu_read_unlock();
884
885 return tun;
886}
887
888static void tun_put(struct tun_struct *tun)
889{
890 dev_put(tun->dev);
891}
892
893/* TAP filtering */
894static void addr_hash_set(u32 *mask, const u8 *addr)
895{
896 int n = ether_crc(ETH_ALEN, addr) >> 26;
897 mask[n >> 5] |= (1 << (n & 31));
898}
899
900static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
901{
902 int n = ether_crc(ETH_ALEN, addr) >> 26;
903 return mask[n >> 5] & (1 << (n & 31));
904}
905
906static int update_filter(struct tap_filter *filter, void __user *arg)
907{
908 struct { u8 u[ETH_ALEN]; } *addr;
909 struct tun_filter uf;
910 int err, alen, n, nexact;
911
912 if (copy_from_user(&uf, arg, sizeof(uf)))
913 return -EFAULT;
914
915 if (!uf.count) {
916 /* Disabled */
917 filter->count = 0;
918 return 0;
919 }
920
921 alen = ETH_ALEN * uf.count;
922 addr = memdup_user(arg + sizeof(uf), alen);
923 if (IS_ERR(addr))
924 return PTR_ERR(addr);
925
926 /* The filter is updated without holding any locks. Which is
927 * perfectly safe. We disable it first and in the worst
928 * case we'll accept a few undesired packets. */
929 filter->count = 0;
930 wmb();
931
932 /* Use first set of addresses as an exact filter */
933 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
934 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
935
936 nexact = n;
937
938 /* Remaining multicast addresses are hashed,
939 * unicast will leave the filter disabled. */
940 memset(filter->mask, 0, sizeof(filter->mask));
941 for (; n < uf.count; n++) {
942 if (!is_multicast_ether_addr(addr[n].u)) {
943 err = 0; /* no filter */
944 goto free_addr;
945 }
946 addr_hash_set(filter->mask, addr[n].u);
947 }
948
949 /* For ALLMULTI just set the mask to all ones.
950 * This overrides the mask populated above. */
951 if ((uf.flags & TUN_FLT_ALLMULTI))
952 memset(filter->mask, ~0, sizeof(filter->mask));
953
954 /* Now enable the filter */
955 wmb();
956 filter->count = nexact;
957
958 /* Return the number of exact filters */
959 err = nexact;
960free_addr:
961 kfree(addr);
962 return err;
963}
964
965/* Returns: 0 - drop, !=0 - accept */
966static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
967{
968 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
969 * at this point. */
970 struct ethhdr *eh = (struct ethhdr *) skb->data;
971 int i;
972
973 /* Exact match */
974 for (i = 0; i < filter->count; i++)
975 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
976 return 1;
977
978 /* Inexact match (multicast only) */
979 if (is_multicast_ether_addr(eh->h_dest))
980 return addr_hash_test(filter->mask, eh->h_dest);
981
982 return 0;
983}
984
985/*
986 * Checks whether the packet is accepted or not.
987 * Returns: 0 - drop, !=0 - accept
988 */
989static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
990{
991 if (!filter->count)
992 return 1;
993
994 return run_filter(filter, skb);
995}
996
997/* Network device part of the driver */
998
999static const struct ethtool_ops tun_ethtool_ops;
1000
1001/* Net device detach from fd. */
1002static void tun_net_uninit(struct net_device *dev)
1003{
1004 tun_detach_all(dev);
1005}
1006
1007/* Net device open. */
1008static int tun_net_open(struct net_device *dev)
1009{
1010 struct tun_struct *tun = netdev_priv(dev);
1011 int i;
1012
1013 netif_tx_start_all_queues(dev);
1014
1015 for (i = 0; i < tun->numqueues; i++) {
1016 struct tun_file *tfile;
1017
1018 tfile = rtnl_dereference(tun->tfiles[i]);
1019 tfile->socket.sk->sk_write_space(tfile->socket.sk);
1020 }
1021
1022 return 0;
1023}
1024
1025/* Net device close. */
1026static int tun_net_close(struct net_device *dev)
1027{
1028 netif_tx_stop_all_queues(dev);
1029 return 0;
1030}
1031
1032/* Net device start xmit */
1033static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1034{
1035#ifdef CONFIG_RPS
1036 if (tun->numqueues == 1 && static_key_false(&rps_needed)) {
1037 /* Select queue was not called for the skbuff, so we extract the
1038 * RPS hash and save it into the flow_table here.
1039 */
1040 __u32 rxhash;
1041
1042 rxhash = __skb_get_hash_symmetric(skb);
1043 if (rxhash) {
1044 struct tun_flow_entry *e;
1045 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
1046 rxhash);
1047 if (e)
1048 tun_flow_save_rps_rxhash(e, rxhash);
1049 }
1050 }
1051#endif
1052}
1053
1054static unsigned int run_ebpf_filter(struct tun_struct *tun,
1055 struct sk_buff *skb,
1056 int len)
1057{
1058 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1059
1060 if (prog)
1061 len = bpf_prog_run_clear_cb(prog->prog, skb);
1062
1063 return len;
1064}
1065
1066/* Net device start xmit */
1067static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1068{
1069 struct tun_struct *tun = netdev_priv(dev);
1070 int txq = skb->queue_mapping;
1071 struct tun_file *tfile;
1072 int len = skb->len;
1073
1074 rcu_read_lock();
1075 tfile = rcu_dereference(tun->tfiles[txq]);
1076
1077 /* Drop packet if interface is not attached */
1078 if (txq >= tun->numqueues)
1079 goto drop;
1080
1081 if (!rcu_dereference(tun->steering_prog))
1082 tun_automq_xmit(tun, skb);
1083
1084 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
1085
1086 BUG_ON(!tfile);
1087
1088 /* Drop if the filter does not like it.
1089 * This is a noop if the filter is disabled.
1090 * Filter can be enabled only for the TAP devices. */
1091 if (!check_filter(&tun->txflt, skb))
1092 goto drop;
1093
1094 if (tfile->socket.sk->sk_filter &&
1095 sk_filter(tfile->socket.sk, skb))
1096 goto drop;
1097
1098 len = run_ebpf_filter(tun, skb, len);
1099 if (len == 0 || pskb_trim(skb, len))
1100 goto drop;
1101
1102 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1103 goto drop;
1104
1105 skb_tx_timestamp(skb);
1106
1107 /* Orphan the skb - required as we might hang on to it
1108 * for indefinite time.
1109 */
1110 skb_orphan(skb);
1111
1112 nf_reset(skb);
1113
1114 if (ptr_ring_produce(&tfile->tx_ring, skb))
1115 goto drop;
1116
1117 /* Notify and wake up reader process */
1118 if (tfile->flags & TUN_FASYNC)
1119 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1120 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1121
1122 rcu_read_unlock();
1123 return NETDEV_TX_OK;
1124
1125drop:
1126 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1127 skb_tx_error(skb);
1128 kfree_skb(skb);
1129 rcu_read_unlock();
1130 return NET_XMIT_DROP;
1131}
1132
1133static void tun_net_mclist(struct net_device *dev)
1134{
1135 /*
1136 * This callback is supposed to deal with mc filter in
1137 * _rx_ path and has nothing to do with the _tx_ path.
1138 * In rx path we always accept everything userspace gives us.
1139 */
1140}
1141
1142static netdev_features_t tun_net_fix_features(struct net_device *dev,
1143 netdev_features_t features)
1144{
1145 struct tun_struct *tun = netdev_priv(dev);
1146
1147 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1148}
1149#ifdef CONFIG_NET_POLL_CONTROLLER
1150static void tun_poll_controller(struct net_device *dev)
1151{
1152 /*
1153 * Tun only receives frames when:
1154 * 1) the char device endpoint gets data from user space
1155 * 2) the tun socket gets a sendmsg call from user space
1156 * If NAPI is not enabled, since both of those are synchronous
1157 * operations, we are guaranteed never to have pending data when we poll
1158 * for it so there is nothing to do here but return.
1159 * We need this though so netpoll recognizes us as an interface that
1160 * supports polling, which enables bridge devices in virt setups to
1161 * still use netconsole
1162 * If NAPI is enabled, however, we need to schedule polling for all
1163 * queues unless we are using napi_gro_frags(), which we call in
1164 * process context and not in NAPI context.
1165 */
1166 struct tun_struct *tun = netdev_priv(dev);
1167
1168 if (tun->flags & IFF_NAPI) {
1169 struct tun_file *tfile;
1170 int i;
1171
1172 if (tun_napi_frags_enabled(tun))
1173 return;
1174
1175 rcu_read_lock();
1176 for (i = 0; i < tun->numqueues; i++) {
1177 tfile = rcu_dereference(tun->tfiles[i]);
1178 if (tfile->napi_enabled)
1179 napi_schedule(&tfile->napi);
1180 }
1181 rcu_read_unlock();
1182 }
1183 return;
1184}
1185#endif
1186
1187static void tun_set_headroom(struct net_device *dev, int new_hr)
1188{
1189 struct tun_struct *tun = netdev_priv(dev);
1190
1191 if (new_hr < NET_SKB_PAD)
1192 new_hr = NET_SKB_PAD;
1193
1194 tun->align = new_hr;
1195}
1196
1197static void
1198tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1199{
1200 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1201 struct tun_struct *tun = netdev_priv(dev);
1202 struct tun_pcpu_stats *p;
1203 int i;
1204
1205 for_each_possible_cpu(i) {
1206 u64 rxpackets, rxbytes, txpackets, txbytes;
1207 unsigned int start;
1208
1209 p = per_cpu_ptr(tun->pcpu_stats, i);
1210 do {
1211 start = u64_stats_fetch_begin(&p->syncp);
1212 rxpackets = p->rx_packets;
1213 rxbytes = p->rx_bytes;
1214 txpackets = p->tx_packets;
1215 txbytes = p->tx_bytes;
1216 } while (u64_stats_fetch_retry(&p->syncp, start));
1217
1218 stats->rx_packets += rxpackets;
1219 stats->rx_bytes += rxbytes;
1220 stats->tx_packets += txpackets;
1221 stats->tx_bytes += txbytes;
1222
1223 /* u32 counters */
1224 rx_dropped += p->rx_dropped;
1225 rx_frame_errors += p->rx_frame_errors;
1226 tx_dropped += p->tx_dropped;
1227 }
1228 stats->rx_dropped = rx_dropped;
1229 stats->rx_frame_errors = rx_frame_errors;
1230 stats->tx_dropped = tx_dropped;
1231}
1232
1233static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1234 struct netlink_ext_ack *extack)
1235{
1236 struct tun_struct *tun = netdev_priv(dev);
1237 struct bpf_prog *old_prog;
1238
1239 old_prog = rtnl_dereference(tun->xdp_prog);
1240 rcu_assign_pointer(tun->xdp_prog, prog);
1241 if (old_prog)
1242 bpf_prog_put(old_prog);
1243
1244 return 0;
1245}
1246
1247static u32 tun_xdp_query(struct net_device *dev)
1248{
1249 struct tun_struct *tun = netdev_priv(dev);
1250 const struct bpf_prog *xdp_prog;
1251
1252 xdp_prog = rtnl_dereference(tun->xdp_prog);
1253 if (xdp_prog)
1254 return xdp_prog->aux->id;
1255
1256 return 0;
1257}
1258
1259static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1260{
1261 switch (xdp->command) {
1262 case XDP_SETUP_PROG:
1263 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1264 case XDP_QUERY_PROG:
1265 xdp->prog_id = tun_xdp_query(dev);
1266 xdp->prog_attached = !!xdp->prog_id;
1267 return 0;
1268 default:
1269 return -EINVAL;
1270 }
1271}
1272
1273static const struct net_device_ops tun_netdev_ops = {
1274 .ndo_uninit = tun_net_uninit,
1275 .ndo_open = tun_net_open,
1276 .ndo_stop = tun_net_close,
1277 .ndo_start_xmit = tun_net_xmit,
1278 .ndo_fix_features = tun_net_fix_features,
1279 .ndo_select_queue = tun_select_queue,
1280#ifdef CONFIG_NET_POLL_CONTROLLER
1281 .ndo_poll_controller = tun_poll_controller,
1282#endif
1283 .ndo_set_rx_headroom = tun_set_headroom,
1284 .ndo_get_stats64 = tun_net_get_stats64,
1285};
1286
1287static int tun_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp)
1288{
1289 struct tun_struct *tun = netdev_priv(dev);
1290 struct xdp_buff *buff = xdp->data_hard_start;
1291 int headroom = xdp->data - xdp->data_hard_start;
1292 struct tun_file *tfile;
1293 u32 numqueues;
1294 int ret = 0;
1295
1296 /* Assure headroom is available and buff is properly aligned */
1297 if (unlikely(headroom < sizeof(*xdp) || tun_is_xdp_buff(xdp)))
1298 return -ENOSPC;
1299
1300 *buff = *xdp;
1301
1302 rcu_read_lock();
1303
1304 numqueues = READ_ONCE(tun->numqueues);
1305 if (!numqueues) {
1306 ret = -ENOSPC;
1307 goto out;
1308 }
1309
1310 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1311 numqueues]);
1312 /* Encode the XDP flag into lowest bit for consumer to differ
1313 * XDP buffer from sk_buff.
1314 */
1315 if (ptr_ring_produce(&tfile->tx_ring, tun_xdp_to_ptr(buff))) {
1316 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1317 ret = -ENOSPC;
1318 }
1319
1320out:
1321 rcu_read_unlock();
1322 return ret;
1323}
1324
1325static void tun_xdp_flush(struct net_device *dev)
1326{
1327 struct tun_struct *tun = netdev_priv(dev);
1328 struct tun_file *tfile;
1329 u32 numqueues;
1330
1331 rcu_read_lock();
1332
1333 numqueues = READ_ONCE(tun->numqueues);
1334 if (!numqueues)
1335 goto out;
1336
1337 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1338 numqueues]);
1339 /* Notify and wake up reader process */
1340 if (tfile->flags & TUN_FASYNC)
1341 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1342 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1343
1344out:
1345 rcu_read_unlock();
1346}
1347
1348static const struct net_device_ops tap_netdev_ops = {
1349 .ndo_uninit = tun_net_uninit,
1350 .ndo_open = tun_net_open,
1351 .ndo_stop = tun_net_close,
1352 .ndo_start_xmit = tun_net_xmit,
1353 .ndo_fix_features = tun_net_fix_features,
1354 .ndo_set_rx_mode = tun_net_mclist,
1355 .ndo_set_mac_address = eth_mac_addr,
1356 .ndo_validate_addr = eth_validate_addr,
1357 .ndo_select_queue = tun_select_queue,
1358#ifdef CONFIG_NET_POLL_CONTROLLER
1359 .ndo_poll_controller = tun_poll_controller,
1360#endif
1361 .ndo_features_check = passthru_features_check,
1362 .ndo_set_rx_headroom = tun_set_headroom,
1363 .ndo_get_stats64 = tun_net_get_stats64,
1364 .ndo_bpf = tun_xdp,
1365 .ndo_xdp_xmit = tun_xdp_xmit,
1366 .ndo_xdp_flush = tun_xdp_flush,
1367};
1368
1369static void tun_flow_init(struct tun_struct *tun)
1370{
1371 int i;
1372
1373 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1374 INIT_HLIST_HEAD(&tun->flows[i]);
1375
1376 tun->ageing_time = TUN_FLOW_EXPIRE;
1377 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1378 mod_timer(&tun->flow_gc_timer,
1379 round_jiffies_up(jiffies + tun->ageing_time));
1380}
1381
1382static void tun_flow_uninit(struct tun_struct *tun)
1383{
1384 del_timer_sync(&tun->flow_gc_timer);
1385 tun_flow_flush(tun);
1386}
1387
1388#define MIN_MTU 68
1389#define MAX_MTU 65535
1390
1391/* Initialize net device. */
1392static void tun_net_init(struct net_device *dev)
1393{
1394 struct tun_struct *tun = netdev_priv(dev);
1395
1396 switch (tun->flags & TUN_TYPE_MASK) {
1397 case IFF_TUN:
1398 dev->netdev_ops = &tun_netdev_ops;
1399
1400 /* Point-to-Point TUN Device */
1401 dev->hard_header_len = 0;
1402 dev->addr_len = 0;
1403 dev->mtu = 1500;
1404
1405 /* Zero header length */
1406 dev->type = ARPHRD_NONE;
1407 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1408 break;
1409
1410 case IFF_TAP:
1411 dev->netdev_ops = &tap_netdev_ops;
1412 /* Ethernet TAP Device */
1413 ether_setup(dev);
1414 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1415 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1416
1417 eth_hw_addr_random(dev);
1418
1419 break;
1420 }
1421
1422 dev->min_mtu = MIN_MTU;
1423 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1424}
1425
1426static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1427{
1428 struct sock *sk = tfile->socket.sk;
1429
1430 return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1431}
1432
1433/* Character device part */
1434
1435/* Poll */
1436static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1437{
1438 struct tun_file *tfile = file->private_data;
1439 struct tun_struct *tun = tun_get(tfile);
1440 struct sock *sk;
1441 __poll_t mask = 0;
1442
1443 if (!tun)
1444 return EPOLLERR;
1445
1446 sk = tfile->socket.sk;
1447
1448 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1449
1450 poll_wait(file, sk_sleep(sk), wait);
1451
1452 if (!ptr_ring_empty(&tfile->tx_ring))
1453 mask |= EPOLLIN | EPOLLRDNORM;
1454
1455 /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1456 * guarantee EPOLLOUT to be raised by either here or
1457 * tun_sock_write_space(). Then process could get notification
1458 * after it writes to a down device and meets -EIO.
1459 */
1460 if (tun_sock_writeable(tun, tfile) ||
1461 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1462 tun_sock_writeable(tun, tfile)))
1463 mask |= EPOLLOUT | EPOLLWRNORM;
1464
1465 if (tun->dev->reg_state != NETREG_REGISTERED)
1466 mask = EPOLLERR;
1467
1468 tun_put(tun);
1469 return mask;
1470}
1471
1472static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1473 size_t len,
1474 const struct iov_iter *it)
1475{
1476 struct sk_buff *skb;
1477 size_t linear;
1478 int err;
1479 int i;
1480
1481 if (it->nr_segs > MAX_SKB_FRAGS + 1)
1482 return ERR_PTR(-ENOMEM);
1483
1484 local_bh_disable();
1485 skb = napi_get_frags(&tfile->napi);
1486 local_bh_enable();
1487 if (!skb)
1488 return ERR_PTR(-ENOMEM);
1489
1490 linear = iov_iter_single_seg_count(it);
1491 err = __skb_grow(skb, linear);
1492 if (err)
1493 goto free;
1494
1495 skb->len = len;
1496 skb->data_len = len - linear;
1497 skb->truesize += skb->data_len;
1498
1499 for (i = 1; i < it->nr_segs; i++) {
1500 struct page_frag *pfrag = ¤t->task_frag;
1501 size_t fragsz = it->iov[i].iov_len;
1502
1503 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1504 err = -EINVAL;
1505 goto free;
1506 }
1507
1508 if (!skb_page_frag_refill(fragsz, pfrag, GFP_KERNEL)) {
1509 err = -ENOMEM;
1510 goto free;
1511 }
1512
1513 skb_fill_page_desc(skb, i - 1, pfrag->page,
1514 pfrag->offset, fragsz);
1515 page_ref_inc(pfrag->page);
1516 pfrag->offset += fragsz;
1517 }
1518
1519 return skb;
1520free:
1521 /* frees skb and all frags allocated with napi_alloc_frag() */
1522 napi_free_frags(&tfile->napi);
1523 return ERR_PTR(err);
1524}
1525
1526/* prepad is the amount to reserve at front. len is length after that.
1527 * linear is a hint as to how much to copy (usually headers). */
1528static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1529 size_t prepad, size_t len,
1530 size_t linear, int noblock)
1531{
1532 struct sock *sk = tfile->socket.sk;
1533 struct sk_buff *skb;
1534 int err;
1535
1536 /* Under a page? Don't bother with paged skb. */
1537 if (prepad + len < PAGE_SIZE || !linear)
1538 linear = len;
1539
1540 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1541 &err, 0);
1542 if (!skb)
1543 return ERR_PTR(err);
1544
1545 skb_reserve(skb, prepad);
1546 skb_put(skb, linear);
1547 skb->data_len = len - linear;
1548 skb->len += len - linear;
1549
1550 return skb;
1551}
1552
1553static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1554 struct sk_buff *skb, int more)
1555{
1556 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1557 struct sk_buff_head process_queue;
1558 u32 rx_batched = tun->rx_batched;
1559 bool rcv = false;
1560
1561 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1562 local_bh_disable();
1563 netif_receive_skb(skb);
1564 local_bh_enable();
1565 return;
1566 }
1567
1568 spin_lock(&queue->lock);
1569 if (!more || skb_queue_len(queue) == rx_batched) {
1570 __skb_queue_head_init(&process_queue);
1571 skb_queue_splice_tail_init(queue, &process_queue);
1572 rcv = true;
1573 } else {
1574 __skb_queue_tail(queue, skb);
1575 }
1576 spin_unlock(&queue->lock);
1577
1578 if (rcv) {
1579 struct sk_buff *nskb;
1580
1581 local_bh_disable();
1582 while ((nskb = __skb_dequeue(&process_queue)))
1583 netif_receive_skb(nskb);
1584 netif_receive_skb(skb);
1585 local_bh_enable();
1586 }
1587}
1588
1589static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1590 int len, int noblock, bool zerocopy)
1591{
1592 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1593 return false;
1594
1595 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1596 return false;
1597
1598 if (!noblock)
1599 return false;
1600
1601 if (zerocopy)
1602 return false;
1603
1604 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1605 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1606 return false;
1607
1608 return true;
1609}
1610
1611static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1612 struct tun_file *tfile,
1613 struct iov_iter *from,
1614 struct virtio_net_hdr *hdr,
1615 int len, int *skb_xdp)
1616{
1617 struct page_frag *alloc_frag = ¤t->task_frag;
1618 struct sk_buff *skb;
1619 struct bpf_prog *xdp_prog;
1620 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1621 unsigned int delta = 0;
1622 char *buf;
1623 size_t copied;
1624 int err, pad = TUN_RX_PAD;
1625
1626 rcu_read_lock();
1627 xdp_prog = rcu_dereference(tun->xdp_prog);
1628 if (xdp_prog)
1629 pad += TUN_HEADROOM;
1630 buflen += SKB_DATA_ALIGN(len + pad);
1631 rcu_read_unlock();
1632
1633 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1634 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1635 return ERR_PTR(-ENOMEM);
1636
1637 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1638 copied = copy_page_from_iter(alloc_frag->page,
1639 alloc_frag->offset + pad,
1640 len, from);
1641 if (copied != len)
1642 return ERR_PTR(-EFAULT);
1643
1644 /* There's a small window that XDP may be set after the check
1645 * of xdp_prog above, this should be rare and for simplicity
1646 * we do XDP on skb in case the headroom is not enough.
1647 */
1648 if (hdr->gso_type || !xdp_prog)
1649 *skb_xdp = 1;
1650 else
1651 *skb_xdp = 0;
1652
1653 local_bh_disable();
1654 rcu_read_lock();
1655 xdp_prog = rcu_dereference(tun->xdp_prog);
1656 if (xdp_prog && !*skb_xdp) {
1657 struct xdp_buff xdp;
1658 void *orig_data;
1659 u32 act;
1660
1661 xdp.data_hard_start = buf;
1662 xdp.data = buf + pad;
1663 xdp_set_data_meta_invalid(&xdp);
1664 xdp.data_end = xdp.data + len;
1665 xdp.rxq = &tfile->xdp_rxq;
1666 orig_data = xdp.data;
1667 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1668
1669 switch (act) {
1670 case XDP_REDIRECT:
1671 get_page(alloc_frag->page);
1672 alloc_frag->offset += buflen;
1673 err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
1674 xdp_do_flush_map();
1675 if (err)
1676 goto err_redirect;
1677 rcu_read_unlock();
1678 local_bh_enable();
1679 return NULL;
1680 case XDP_TX:
1681 get_page(alloc_frag->page);
1682 alloc_frag->offset += buflen;
1683 if (tun_xdp_xmit(tun->dev, &xdp))
1684 goto err_redirect;
1685 tun_xdp_flush(tun->dev);
1686 rcu_read_unlock();
1687 local_bh_enable();
1688 return NULL;
1689 case XDP_PASS:
1690 delta = orig_data - xdp.data;
1691 break;
1692 default:
1693 bpf_warn_invalid_xdp_action(act);
1694 /* fall through */
1695 case XDP_ABORTED:
1696 trace_xdp_exception(tun->dev, xdp_prog, act);
1697 /* fall through */
1698 case XDP_DROP:
1699 goto err_xdp;
1700 }
1701 }
1702
1703 skb = build_skb(buf, buflen);
1704 if (!skb) {
1705 rcu_read_unlock();
1706 local_bh_enable();
1707 return ERR_PTR(-ENOMEM);
1708 }
1709
1710 skb_reserve(skb, pad - delta);
1711 skb_put(skb, len + delta);
1712 get_page(alloc_frag->page);
1713 alloc_frag->offset += buflen;
1714
1715 rcu_read_unlock();
1716 local_bh_enable();
1717
1718 return skb;
1719
1720err_redirect:
1721 put_page(alloc_frag->page);
1722err_xdp:
1723 rcu_read_unlock();
1724 local_bh_enable();
1725 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1726 return NULL;
1727}
1728
1729/* Get packet from user space buffer */
1730static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1731 void *msg_control, struct iov_iter *from,
1732 int noblock, bool more)
1733{
1734 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1735 struct sk_buff *skb;
1736 size_t total_len = iov_iter_count(from);
1737 size_t len = total_len, align = tun->align, linear;
1738 struct virtio_net_hdr gso = { 0 };
1739 struct tun_pcpu_stats *stats;
1740 int good_linear;
1741 int copylen;
1742 bool zerocopy = false;
1743 int err;
1744 u32 rxhash = 0;
1745 int skb_xdp = 1;
1746 bool frags = tun_napi_frags_enabled(tun);
1747
1748 if (!(tun->dev->flags & IFF_UP))
1749 return -EIO;
1750
1751 if (!(tun->flags & IFF_NO_PI)) {
1752 if (len < sizeof(pi))
1753 return -EINVAL;
1754 len -= sizeof(pi);
1755
1756 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1757 return -EFAULT;
1758 }
1759
1760 if (tun->flags & IFF_VNET_HDR) {
1761 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1762
1763 if (len < vnet_hdr_sz)
1764 return -EINVAL;
1765 len -= vnet_hdr_sz;
1766
1767 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1768 return -EFAULT;
1769
1770 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1771 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1772 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1773
1774 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1775 return -EINVAL;
1776 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1777 }
1778
1779 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1780 align += NET_IP_ALIGN;
1781 if (unlikely(len < ETH_HLEN ||
1782 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1783 return -EINVAL;
1784 }
1785
1786 good_linear = SKB_MAX_HEAD(align);
1787
1788 if (msg_control) {
1789 struct iov_iter i = *from;
1790
1791 /* There are 256 bytes to be copied in skb, so there is
1792 * enough room for skb expand head in case it is used.
1793 * The rest of the buffer is mapped from userspace.
1794 */
1795 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1796 if (copylen > good_linear)
1797 copylen = good_linear;
1798 linear = copylen;
1799 iov_iter_advance(&i, copylen);
1800 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1801 zerocopy = true;
1802 }
1803
1804 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1805 /* For the packet that is not easy to be processed
1806 * (e.g gso or jumbo packet), we will do it at after
1807 * skb was created with generic XDP routine.
1808 */
1809 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1810 if (IS_ERR(skb)) {
1811 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1812 return PTR_ERR(skb);
1813 }
1814 if (!skb)
1815 return total_len;
1816 } else {
1817 if (!zerocopy) {
1818 copylen = len;
1819 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1820 linear = good_linear;
1821 else
1822 linear = tun16_to_cpu(tun, gso.hdr_len);
1823 }
1824
1825 if (frags) {
1826 mutex_lock(&tfile->napi_mutex);
1827 skb = tun_napi_alloc_frags(tfile, copylen, from);
1828 /* tun_napi_alloc_frags() enforces a layout for the skb.
1829 * If zerocopy is enabled, then this layout will be
1830 * overwritten by zerocopy_sg_from_iter().
1831 */
1832 zerocopy = false;
1833 } else {
1834 skb = tun_alloc_skb(tfile, align, copylen, linear,
1835 noblock);
1836 }
1837
1838 if (IS_ERR(skb)) {
1839 if (PTR_ERR(skb) != -EAGAIN)
1840 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1841 if (frags)
1842 mutex_unlock(&tfile->napi_mutex);
1843 return PTR_ERR(skb);
1844 }
1845
1846 if (zerocopy)
1847 err = zerocopy_sg_from_iter(skb, from);
1848 else
1849 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1850
1851 if (err) {
1852 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1853 kfree_skb(skb);
1854 if (frags) {
1855 tfile->napi.skb = NULL;
1856 mutex_unlock(&tfile->napi_mutex);
1857 }
1858
1859 return -EFAULT;
1860 }
1861 }
1862
1863 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1864 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1865 kfree_skb(skb);
1866 if (frags) {
1867 tfile->napi.skb = NULL;
1868 mutex_unlock(&tfile->napi_mutex);
1869 }
1870
1871 return -EINVAL;
1872 }
1873
1874 switch (tun->flags & TUN_TYPE_MASK) {
1875 case IFF_TUN:
1876 if (tun->flags & IFF_NO_PI) {
1877 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1878
1879 switch (ip_version) {
1880 case 4:
1881 pi.proto = htons(ETH_P_IP);
1882 break;
1883 case 6:
1884 pi.proto = htons(ETH_P_IPV6);
1885 break;
1886 default:
1887 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1888 kfree_skb(skb);
1889 return -EINVAL;
1890 }
1891 }
1892
1893 skb_reset_mac_header(skb);
1894 skb->protocol = pi.proto;
1895 skb->dev = tun->dev;
1896 break;
1897 case IFF_TAP:
1898 if (!frags)
1899 skb->protocol = eth_type_trans(skb, tun->dev);
1900 break;
1901 }
1902
1903 /* copy skb_ubuf_info for callback when skb has no error */
1904 if (zerocopy) {
1905 skb_shinfo(skb)->destructor_arg = msg_control;
1906 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1907 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1908 } else if (msg_control) {
1909 struct ubuf_info *uarg = msg_control;
1910 uarg->callback(uarg, false);
1911 }
1912
1913 skb_reset_network_header(skb);
1914 skb_probe_transport_header(skb, 0);
1915
1916 if (skb_xdp) {
1917 struct bpf_prog *xdp_prog;
1918 int ret;
1919
1920 local_bh_disable();
1921 rcu_read_lock();
1922 xdp_prog = rcu_dereference(tun->xdp_prog);
1923 if (xdp_prog) {
1924 ret = do_xdp_generic(xdp_prog, skb);
1925 if (ret != XDP_PASS) {
1926 rcu_read_unlock();
1927 local_bh_enable();
1928 return total_len;
1929 }
1930 }
1931 rcu_read_unlock();
1932 local_bh_enable();
1933 }
1934
1935 rcu_read_lock();
1936 if (!rcu_dereference(tun->steering_prog))
1937 rxhash = __skb_get_hash_symmetric(skb);
1938 rcu_read_unlock();
1939
1940 if (frags) {
1941 /* Exercise flow dissector code path. */
1942 u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb));
1943
1944 if (unlikely(headlen > skb_headlen(skb))) {
1945 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1946 napi_free_frags(&tfile->napi);
1947 mutex_unlock(&tfile->napi_mutex);
1948 WARN_ON(1);
1949 return -ENOMEM;
1950 }
1951
1952 local_bh_disable();
1953 napi_gro_frags(&tfile->napi);
1954 local_bh_enable();
1955 mutex_unlock(&tfile->napi_mutex);
1956 } else if (tfile->napi_enabled) {
1957 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1958 int queue_len;
1959
1960 spin_lock_bh(&queue->lock);
1961 __skb_queue_tail(queue, skb);
1962 queue_len = skb_queue_len(queue);
1963 spin_unlock(&queue->lock);
1964
1965 if (!more || queue_len > NAPI_POLL_WEIGHT)
1966 napi_schedule(&tfile->napi);
1967
1968 local_bh_enable();
1969 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1970 tun_rx_batched(tun, tfile, skb, more);
1971 } else {
1972 netif_rx_ni(skb);
1973 }
1974
1975 stats = get_cpu_ptr(tun->pcpu_stats);
1976 u64_stats_update_begin(&stats->syncp);
1977 stats->rx_packets++;
1978 stats->rx_bytes += len;
1979 u64_stats_update_end(&stats->syncp);
1980 put_cpu_ptr(stats);
1981
1982 if (rxhash)
1983 tun_flow_update(tun, rxhash, tfile);
1984
1985 return total_len;
1986}
1987
1988static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1989{
1990 struct file *file = iocb->ki_filp;
1991 struct tun_file *tfile = file->private_data;
1992 struct tun_struct *tun = tun_get(tfile);
1993 ssize_t result;
1994
1995 if (!tun)
1996 return -EBADFD;
1997
1998 result = tun_get_user(tun, tfile, NULL, from,
1999 file->f_flags & O_NONBLOCK, false);
2000
2001 tun_put(tun);
2002 return result;
2003}
2004
2005static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2006 struct tun_file *tfile,
2007 struct xdp_buff *xdp,
2008 struct iov_iter *iter)
2009{
2010 int vnet_hdr_sz = 0;
2011 size_t size = xdp->data_end - xdp->data;
2012 struct tun_pcpu_stats *stats;
2013 size_t ret;
2014
2015 if (tun->flags & IFF_VNET_HDR) {
2016 struct virtio_net_hdr gso = { 0 };
2017
2018 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2019 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2020 return -EINVAL;
2021 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2022 sizeof(gso)))
2023 return -EFAULT;
2024 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2025 }
2026
2027 ret = copy_to_iter(xdp->data, size, iter) + vnet_hdr_sz;
2028
2029 stats = get_cpu_ptr(tun->pcpu_stats);
2030 u64_stats_update_begin(&stats->syncp);
2031 stats->tx_packets++;
2032 stats->tx_bytes += ret;
2033 u64_stats_update_end(&stats->syncp);
2034 put_cpu_ptr(tun->pcpu_stats);
2035
2036 return ret;
2037}
2038
2039/* Put packet to the user space buffer */
2040static ssize_t tun_put_user(struct tun_struct *tun,
2041 struct tun_file *tfile,
2042 struct sk_buff *skb,
2043 struct iov_iter *iter)
2044{
2045 struct tun_pi pi = { 0, skb->protocol };
2046 struct tun_pcpu_stats *stats;
2047 ssize_t total;
2048 int vlan_offset = 0;
2049 int vlan_hlen = 0;
2050 int vnet_hdr_sz = 0;
2051
2052 if (skb_vlan_tag_present(skb))
2053 vlan_hlen = VLAN_HLEN;
2054
2055 if (tun->flags & IFF_VNET_HDR)
2056 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2057
2058 total = skb->len + vlan_hlen + vnet_hdr_sz;
2059
2060 if (!(tun->flags & IFF_NO_PI)) {
2061 if (iov_iter_count(iter) < sizeof(pi))
2062 return -EINVAL;
2063
2064 total += sizeof(pi);
2065 if (iov_iter_count(iter) < total) {
2066 /* Packet will be striped */
2067 pi.flags |= TUN_PKT_STRIP;
2068 }
2069
2070 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2071 return -EFAULT;
2072 }
2073
2074 if (vnet_hdr_sz) {
2075 struct virtio_net_hdr gso;
2076
2077 if (iov_iter_count(iter) < vnet_hdr_sz)
2078 return -EINVAL;
2079
2080 if (virtio_net_hdr_from_skb(skb, &gso,
2081 tun_is_little_endian(tun), true)) {
2082 struct skb_shared_info *sinfo = skb_shinfo(skb);
2083 pr_err("unexpected GSO type: "
2084 "0x%x, gso_size %d, hdr_len %d\n",
2085 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2086 tun16_to_cpu(tun, gso.hdr_len));
2087 print_hex_dump(KERN_ERR, "tun: ",
2088 DUMP_PREFIX_NONE,
2089 16, 1, skb->head,
2090 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2091 WARN_ON_ONCE(1);
2092 return -EINVAL;
2093 }
2094
2095 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2096 return -EFAULT;
2097
2098 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2099 }
2100
2101 if (vlan_hlen) {
2102 int ret;
2103 struct veth veth;
2104
2105 veth.h_vlan_proto = skb->vlan_proto;
2106 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2107
2108 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2109
2110 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2111 if (ret || !iov_iter_count(iter))
2112 goto done;
2113
2114 ret = copy_to_iter(&veth, sizeof(veth), iter);
2115 if (ret != sizeof(veth) || !iov_iter_count(iter))
2116 goto done;
2117 }
2118
2119 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2120
2121done:
2122 /* caller is in process context, */
2123 stats = get_cpu_ptr(tun->pcpu_stats);
2124 u64_stats_update_begin(&stats->syncp);
2125 stats->tx_packets++;
2126 stats->tx_bytes += skb->len + vlan_hlen;
2127 u64_stats_update_end(&stats->syncp);
2128 put_cpu_ptr(tun->pcpu_stats);
2129
2130 return total;
2131}
2132
2133static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2134{
2135 DECLARE_WAITQUEUE(wait, current);
2136 void *ptr = NULL;
2137 int error = 0;
2138
2139 ptr = ptr_ring_consume(&tfile->tx_ring);
2140 if (ptr)
2141 goto out;
2142 if (noblock) {
2143 error = -EAGAIN;
2144 goto out;
2145 }
2146
2147 add_wait_queue(&tfile->wq.wait, &wait);
2148 current->state = TASK_INTERRUPTIBLE;
2149
2150 while (1) {
2151 ptr = ptr_ring_consume(&tfile->tx_ring);
2152 if (ptr)
2153 break;
2154 if (signal_pending(current)) {
2155 error = -ERESTARTSYS;
2156 break;
2157 }
2158 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2159 error = -EFAULT;
2160 break;
2161 }
2162
2163 schedule();
2164 }
2165
2166 current->state = TASK_RUNNING;
2167 remove_wait_queue(&tfile->wq.wait, &wait);
2168
2169out:
2170 *err = error;
2171 return ptr;
2172}
2173
2174static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2175 struct iov_iter *to,
2176 int noblock, void *ptr)
2177{
2178 ssize_t ret;
2179 int err;
2180
2181 tun_debug(KERN_INFO, tun, "tun_do_read\n");
2182
2183 if (!iov_iter_count(to)) {
2184 tun_ptr_free(ptr);
2185 return 0;
2186 }
2187
2188 if (!ptr) {
2189 /* Read frames from ring */
2190 ptr = tun_ring_recv(tfile, noblock, &err);
2191 if (!ptr)
2192 return err;
2193 }
2194
2195 if (tun_is_xdp_buff(ptr)) {
2196 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
2197
2198 ret = tun_put_user_xdp(tun, tfile, xdp, to);
2199 put_page(virt_to_head_page(xdp->data));
2200 } else {
2201 struct sk_buff *skb = ptr;
2202
2203 ret = tun_put_user(tun, tfile, skb, to);
2204 if (unlikely(ret < 0))
2205 kfree_skb(skb);
2206 else
2207 consume_skb(skb);
2208 }
2209
2210 return ret;
2211}
2212
2213static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2214{
2215 struct file *file = iocb->ki_filp;
2216 struct tun_file *tfile = file->private_data;
2217 struct tun_struct *tun = tun_get(tfile);
2218 ssize_t len = iov_iter_count(to), ret;
2219
2220 if (!tun)
2221 return -EBADFD;
2222 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2223 ret = min_t(ssize_t, ret, len);
2224 if (ret > 0)
2225 iocb->ki_pos = ret;
2226 tun_put(tun);
2227 return ret;
2228}
2229
2230static void tun_prog_free(struct rcu_head *rcu)
2231{
2232 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2233
2234 bpf_prog_destroy(prog->prog);
2235 kfree(prog);
2236}
2237
2238static int __tun_set_ebpf(struct tun_struct *tun,
2239 struct tun_prog __rcu **prog_p,
2240 struct bpf_prog *prog)
2241{
2242 struct tun_prog *old, *new = NULL;
2243
2244 if (prog) {
2245 new = kmalloc(sizeof(*new), GFP_KERNEL);
2246 if (!new)
2247 return -ENOMEM;
2248 new->prog = prog;
2249 }
2250
2251 spin_lock_bh(&tun->lock);
2252 old = rcu_dereference_protected(*prog_p,
2253 lockdep_is_held(&tun->lock));
2254 rcu_assign_pointer(*prog_p, new);
2255 spin_unlock_bh(&tun->lock);
2256
2257 if (old)
2258 call_rcu(&old->rcu, tun_prog_free);
2259
2260 return 0;
2261}
2262
2263static void tun_free_netdev(struct net_device *dev)
2264{
2265 struct tun_struct *tun = netdev_priv(dev);
2266
2267 BUG_ON(!(list_empty(&tun->disabled)));
2268 free_percpu(tun->pcpu_stats);
2269 tun_flow_uninit(tun);
2270 security_tun_dev_free_security(tun->security);
2271 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2272 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2273}
2274
2275static void tun_setup(struct net_device *dev)
2276{
2277 struct tun_struct *tun = netdev_priv(dev);
2278
2279 tun->owner = INVALID_UID;
2280 tun->group = INVALID_GID;
2281
2282 dev->ethtool_ops = &tun_ethtool_ops;
2283 dev->needs_free_netdev = true;
2284 dev->priv_destructor = tun_free_netdev;
2285 /* We prefer our own queue length */
2286 dev->tx_queue_len = TUN_READQ_SIZE;
2287}
2288
2289/* Trivial set of netlink ops to allow deleting tun or tap
2290 * device with netlink.
2291 */
2292static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2293 struct netlink_ext_ack *extack)
2294{
2295 return -EINVAL;
2296}
2297
2298static size_t tun_get_size(const struct net_device *dev)
2299{
2300 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2301 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2302
2303 return nla_total_size(sizeof(uid_t)) + /* OWNER */
2304 nla_total_size(sizeof(gid_t)) + /* GROUP */
2305 nla_total_size(sizeof(u8)) + /* TYPE */
2306 nla_total_size(sizeof(u8)) + /* PI */
2307 nla_total_size(sizeof(u8)) + /* VNET_HDR */
2308 nla_total_size(sizeof(u8)) + /* PERSIST */
2309 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2310 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2311 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2312 0;
2313}
2314
2315static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2316{
2317 struct tun_struct *tun = netdev_priv(dev);
2318
2319 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2320 goto nla_put_failure;
2321 if (uid_valid(tun->owner) &&
2322 nla_put_u32(skb, IFLA_TUN_OWNER,
2323 from_kuid_munged(current_user_ns(), tun->owner)))
2324 goto nla_put_failure;
2325 if (gid_valid(tun->group) &&
2326 nla_put_u32(skb, IFLA_TUN_GROUP,
2327 from_kgid_munged(current_user_ns(), tun->group)))
2328 goto nla_put_failure;
2329 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2330 goto nla_put_failure;
2331 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2332 goto nla_put_failure;
2333 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2334 goto nla_put_failure;
2335 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2336 !!(tun->flags & IFF_MULTI_QUEUE)))
2337 goto nla_put_failure;
2338 if (tun->flags & IFF_MULTI_QUEUE) {
2339 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2340 goto nla_put_failure;
2341 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2342 tun->numdisabled))
2343 goto nla_put_failure;
2344 }
2345
2346 return 0;
2347
2348nla_put_failure:
2349 return -EMSGSIZE;
2350}
2351
2352static struct rtnl_link_ops tun_link_ops __read_mostly = {
2353 .kind = DRV_NAME,
2354 .priv_size = sizeof(struct tun_struct),
2355 .setup = tun_setup,
2356 .validate = tun_validate,
2357 .get_size = tun_get_size,
2358 .fill_info = tun_fill_info,
2359};
2360
2361static void tun_sock_write_space(struct sock *sk)
2362{
2363 struct tun_file *tfile;
2364 wait_queue_head_t *wqueue;
2365
2366 if (!sock_writeable(sk))
2367 return;
2368
2369 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2370 return;
2371
2372 wqueue = sk_sleep(sk);
2373 if (wqueue && waitqueue_active(wqueue))
2374 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2375 EPOLLWRNORM | EPOLLWRBAND);
2376
2377 tfile = container_of(sk, struct tun_file, sk);
2378 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2379}
2380
2381static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2382{
2383 int ret;
2384 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2385 struct tun_struct *tun = tun_get(tfile);
2386
2387 if (!tun)
2388 return -EBADFD;
2389
2390 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
2391 m->msg_flags & MSG_DONTWAIT,
2392 m->msg_flags & MSG_MORE);
2393 tun_put(tun);
2394 return ret;
2395}
2396
2397static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2398 int flags)
2399{
2400 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2401 struct tun_struct *tun = tun_get(tfile);
2402 void *ptr = m->msg_control;
2403 int ret;
2404
2405 if (!tun) {
2406 ret = -EBADFD;
2407 goto out_free;
2408 }
2409
2410 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2411 ret = -EINVAL;
2412 goto out_put_tun;
2413 }
2414 if (flags & MSG_ERRQUEUE) {
2415 ret = sock_recv_errqueue(sock->sk, m, total_len,
2416 SOL_PACKET, TUN_TX_TIMESTAMP);
2417 goto out;
2418 }
2419 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2420 if (ret > (ssize_t)total_len) {
2421 m->msg_flags |= MSG_TRUNC;
2422 ret = flags & MSG_TRUNC ? ret : total_len;
2423 }
2424out:
2425 tun_put(tun);
2426 return ret;
2427
2428out_put_tun:
2429 tun_put(tun);
2430out_free:
2431 tun_ptr_free(ptr);
2432 return ret;
2433}
2434
2435static int tun_ptr_peek_len(void *ptr)
2436{
2437 if (likely(ptr)) {
2438 if (tun_is_xdp_buff(ptr)) {
2439 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
2440
2441 return xdp->data_end - xdp->data;
2442 }
2443 return __skb_array_len_with_tag(ptr);
2444 } else {
2445 return 0;
2446 }
2447}
2448
2449static int tun_peek_len(struct socket *sock)
2450{
2451 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2452 struct tun_struct *tun;
2453 int ret = 0;
2454
2455 tun = tun_get(tfile);
2456 if (!tun)
2457 return 0;
2458
2459 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2460 tun_put(tun);
2461
2462 return ret;
2463}
2464
2465/* Ops structure to mimic raw sockets with tun */
2466static const struct proto_ops tun_socket_ops = {
2467 .peek_len = tun_peek_len,
2468 .sendmsg = tun_sendmsg,
2469 .recvmsg = tun_recvmsg,
2470};
2471
2472static struct proto tun_proto = {
2473 .name = "tun",
2474 .owner = THIS_MODULE,
2475 .obj_size = sizeof(struct tun_file),
2476};
2477
2478static int tun_flags(struct tun_struct *tun)
2479{
2480 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2481}
2482
2483static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2484 char *buf)
2485{
2486 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2487 return sprintf(buf, "0x%x\n", tun_flags(tun));
2488}
2489
2490static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2491 char *buf)
2492{
2493 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2494 return uid_valid(tun->owner)?
2495 sprintf(buf, "%u\n",
2496 from_kuid_munged(current_user_ns(), tun->owner)):
2497 sprintf(buf, "-1\n");
2498}
2499
2500static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2501 char *buf)
2502{
2503 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2504 return gid_valid(tun->group) ?
2505 sprintf(buf, "%u\n",
2506 from_kgid_munged(current_user_ns(), tun->group)):
2507 sprintf(buf, "-1\n");
2508}
2509
2510static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2511static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2512static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2513
2514static struct attribute *tun_dev_attrs[] = {
2515 &dev_attr_tun_flags.attr,
2516 &dev_attr_owner.attr,
2517 &dev_attr_group.attr,
2518 NULL
2519};
2520
2521static const struct attribute_group tun_attr_group = {
2522 .attrs = tun_dev_attrs
2523};
2524
2525static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2526{
2527 struct tun_struct *tun;
2528 struct tun_file *tfile = file->private_data;
2529 struct net_device *dev;
2530 int err;
2531
2532 if (tfile->detached)
2533 return -EINVAL;
2534
2535 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2536 if (!capable(CAP_NET_ADMIN))
2537 return -EPERM;
2538
2539 if (!(ifr->ifr_flags & IFF_NAPI) ||
2540 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2541 return -EINVAL;
2542 }
2543
2544 dev = __dev_get_by_name(net, ifr->ifr_name);
2545 if (dev) {
2546 if (ifr->ifr_flags & IFF_TUN_EXCL)
2547 return -EBUSY;
2548 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2549 tun = netdev_priv(dev);
2550 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2551 tun = netdev_priv(dev);
2552 else
2553 return -EINVAL;
2554
2555 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2556 !!(tun->flags & IFF_MULTI_QUEUE))
2557 return -EINVAL;
2558
2559 if (tun_not_capable(tun))
2560 return -EPERM;
2561 err = security_tun_dev_open(tun->security);
2562 if (err < 0)
2563 return err;
2564
2565 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2566 ifr->ifr_flags & IFF_NAPI);
2567 if (err < 0)
2568 return err;
2569
2570 if (tun->flags & IFF_MULTI_QUEUE &&
2571 (tun->numqueues + tun->numdisabled > 1)) {
2572 /* One or more queue has already been attached, no need
2573 * to initialize the device again.
2574 */
2575 netdev_state_change(dev);
2576 return 0;
2577 }
2578
2579 tun->flags = (tun->flags & ~TUN_FEATURES) |
2580 (ifr->ifr_flags & TUN_FEATURES);
2581
2582 netdev_state_change(dev);
2583 } else {
2584 char *name;
2585 unsigned long flags = 0;
2586 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2587 MAX_TAP_QUEUES : 1;
2588
2589 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2590 return -EPERM;
2591 err = security_tun_dev_create();
2592 if (err < 0)
2593 return err;
2594
2595 /* Set dev type */
2596 if (ifr->ifr_flags & IFF_TUN) {
2597 /* TUN device */
2598 flags |= IFF_TUN;
2599 name = "tun%d";
2600 } else if (ifr->ifr_flags & IFF_TAP) {
2601 /* TAP device */
2602 flags |= IFF_TAP;
2603 name = "tap%d";
2604 } else
2605 return -EINVAL;
2606
2607 if (*ifr->ifr_name)
2608 name = ifr->ifr_name;
2609
2610 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2611 NET_NAME_UNKNOWN, tun_setup, queues,
2612 queues);
2613
2614 if (!dev)
2615 return -ENOMEM;
2616 err = dev_get_valid_name(net, dev, name);
2617 if (err < 0)
2618 goto err_free_dev;
2619
2620 dev_net_set(dev, net);
2621 dev->rtnl_link_ops = &tun_link_ops;
2622 dev->ifindex = tfile->ifindex;
2623 dev->sysfs_groups[0] = &tun_attr_group;
2624
2625 tun = netdev_priv(dev);
2626 tun->dev = dev;
2627 tun->flags = flags;
2628 tun->txflt.count = 0;
2629 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2630
2631 tun->align = NET_SKB_PAD;
2632 tun->filter_attached = false;
2633 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2634 tun->rx_batched = 0;
2635 RCU_INIT_POINTER(tun->steering_prog, NULL);
2636
2637 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2638 if (!tun->pcpu_stats) {
2639 err = -ENOMEM;
2640 goto err_free_dev;
2641 }
2642
2643 spin_lock_init(&tun->lock);
2644
2645 err = security_tun_dev_alloc_security(&tun->security);
2646 if (err < 0)
2647 goto err_free_stat;
2648
2649 tun_net_init(dev);
2650 tun_flow_init(tun);
2651
2652 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2653 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2654 NETIF_F_HW_VLAN_STAG_TX;
2655 dev->features = dev->hw_features | NETIF_F_LLTX;
2656 dev->vlan_features = dev->features &
2657 ~(NETIF_F_HW_VLAN_CTAG_TX |
2658 NETIF_F_HW_VLAN_STAG_TX);
2659
2660 tun->flags = (tun->flags & ~TUN_FEATURES) |
2661 (ifr->ifr_flags & TUN_FEATURES);
2662
2663 INIT_LIST_HEAD(&tun->disabled);
2664 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI);
2665 if (err < 0)
2666 goto err_free_flow;
2667
2668 err = register_netdevice(tun->dev);
2669 if (err < 0)
2670 goto err_detach;
2671 }
2672
2673 netif_carrier_on(tun->dev);
2674
2675 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2676
2677 /* Make sure persistent devices do not get stuck in
2678 * xoff state.
2679 */
2680 if (netif_running(tun->dev))
2681 netif_tx_wake_all_queues(tun->dev);
2682
2683 strcpy(ifr->ifr_name, tun->dev->name);
2684 return 0;
2685
2686err_detach:
2687 tun_detach_all(dev);
2688 /* register_netdevice() already called tun_free_netdev() */
2689 goto err_free_dev;
2690
2691err_free_flow:
2692 tun_flow_uninit(tun);
2693 security_tun_dev_free_security(tun->security);
2694err_free_stat:
2695 free_percpu(tun->pcpu_stats);
2696err_free_dev:
2697 free_netdev(dev);
2698 return err;
2699}
2700
2701static void tun_get_iff(struct net *net, struct tun_struct *tun,
2702 struct ifreq *ifr)
2703{
2704 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2705
2706 strcpy(ifr->ifr_name, tun->dev->name);
2707
2708 ifr->ifr_flags = tun_flags(tun);
2709
2710}
2711
2712/* This is like a cut-down ethtool ops, except done via tun fd so no
2713 * privs required. */
2714static int set_offload(struct tun_struct *tun, unsigned long arg)
2715{
2716 netdev_features_t features = 0;
2717
2718 if (arg & TUN_F_CSUM) {
2719 features |= NETIF_F_HW_CSUM;
2720 arg &= ~TUN_F_CSUM;
2721
2722 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2723 if (arg & TUN_F_TSO_ECN) {
2724 features |= NETIF_F_TSO_ECN;
2725 arg &= ~TUN_F_TSO_ECN;
2726 }
2727 if (arg & TUN_F_TSO4)
2728 features |= NETIF_F_TSO;
2729 if (arg & TUN_F_TSO6)
2730 features |= NETIF_F_TSO6;
2731 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2732 }
2733
2734 arg &= ~TUN_F_UFO;
2735 }
2736
2737 /* This gives the user a way to test for new features in future by
2738 * trying to set them. */
2739 if (arg)
2740 return -EINVAL;
2741
2742 tun->set_features = features;
2743 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2744 tun->dev->wanted_features |= features;
2745 netdev_update_features(tun->dev);
2746
2747 return 0;
2748}
2749
2750static void tun_detach_filter(struct tun_struct *tun, int n)
2751{
2752 int i;
2753 struct tun_file *tfile;
2754
2755 for (i = 0; i < n; i++) {
2756 tfile = rtnl_dereference(tun->tfiles[i]);
2757 lock_sock(tfile->socket.sk);
2758 sk_detach_filter(tfile->socket.sk);
2759 release_sock(tfile->socket.sk);
2760 }
2761
2762 tun->filter_attached = false;
2763}
2764
2765static int tun_attach_filter(struct tun_struct *tun)
2766{
2767 int i, ret = 0;
2768 struct tun_file *tfile;
2769
2770 for (i = 0; i < tun->numqueues; i++) {
2771 tfile = rtnl_dereference(tun->tfiles[i]);
2772 lock_sock(tfile->socket.sk);
2773 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2774 release_sock(tfile->socket.sk);
2775 if (ret) {
2776 tun_detach_filter(tun, i);
2777 return ret;
2778 }
2779 }
2780
2781 tun->filter_attached = true;
2782 return ret;
2783}
2784
2785static void tun_set_sndbuf(struct tun_struct *tun)
2786{
2787 struct tun_file *tfile;
2788 int i;
2789
2790 for (i = 0; i < tun->numqueues; i++) {
2791 tfile = rtnl_dereference(tun->tfiles[i]);
2792 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2793 }
2794}
2795
2796static int tun_set_queue(struct file *file, struct ifreq *ifr)
2797{
2798 struct tun_file *tfile = file->private_data;
2799 struct tun_struct *tun;
2800 int ret = 0;
2801
2802 rtnl_lock();
2803
2804 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2805 tun = tfile->detached;
2806 if (!tun) {
2807 ret = -EINVAL;
2808 goto unlock;
2809 }
2810 ret = security_tun_dev_attach_queue(tun->security);
2811 if (ret < 0)
2812 goto unlock;
2813 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI);
2814 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2815 tun = rtnl_dereference(tfile->tun);
2816 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2817 ret = -EINVAL;
2818 else
2819 __tun_detach(tfile, false);
2820 } else
2821 ret = -EINVAL;
2822
2823 if (ret >= 0)
2824 netdev_state_change(tun->dev);
2825
2826unlock:
2827 rtnl_unlock();
2828 return ret;
2829}
2830
2831static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
2832 void __user *data)
2833{
2834 struct bpf_prog *prog;
2835 int fd;
2836
2837 if (copy_from_user(&fd, data, sizeof(fd)))
2838 return -EFAULT;
2839
2840 if (fd == -1) {
2841 prog = NULL;
2842 } else {
2843 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
2844 if (IS_ERR(prog))
2845 return PTR_ERR(prog);
2846 }
2847
2848 return __tun_set_ebpf(tun, prog_p, prog);
2849}
2850
2851static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2852 unsigned long arg, int ifreq_len)
2853{
2854 struct tun_file *tfile = file->private_data;
2855 struct tun_struct *tun;
2856 void __user* argp = (void __user*)arg;
2857 struct ifreq ifr;
2858 struct net *net;
2859 kuid_t owner;
2860 kgid_t group;
2861 int sndbuf;
2862 int vnet_hdr_sz;
2863 unsigned int ifindex;
2864 int le;
2865 int ret;
2866 bool do_notify = false;
2867
2868 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
2869 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
2870 if (copy_from_user(&ifr, argp, ifreq_len))
2871 return -EFAULT;
2872 } else {
2873 memset(&ifr, 0, sizeof(ifr));
2874 }
2875 if (cmd == TUNGETFEATURES) {
2876 /* Currently this just means: "what IFF flags are valid?".
2877 * This is needed because we never checked for invalid flags on
2878 * TUNSETIFF.
2879 */
2880 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2881 (unsigned int __user*)argp);
2882 } else if (cmd == TUNSETQUEUE)
2883 return tun_set_queue(file, &ifr);
2884
2885 ret = 0;
2886 rtnl_lock();
2887
2888 tun = tun_get(tfile);
2889 net = sock_net(&tfile->sk);
2890 if (cmd == TUNSETIFF) {
2891 ret = -EEXIST;
2892 if (tun)
2893 goto unlock;
2894
2895 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2896
2897 ret = tun_set_iff(net, file, &ifr);
2898
2899 if (ret)
2900 goto unlock;
2901
2902 if (copy_to_user(argp, &ifr, ifreq_len))
2903 ret = -EFAULT;
2904 goto unlock;
2905 }
2906 if (cmd == TUNSETIFINDEX) {
2907 ret = -EPERM;
2908 if (tun)
2909 goto unlock;
2910
2911 ret = -EFAULT;
2912 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2913 goto unlock;
2914
2915 ret = 0;
2916 tfile->ifindex = ifindex;
2917 goto unlock;
2918 }
2919 if (cmd == SIOCGSKNS) {
2920 ret = -EPERM;
2921 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2922 goto unlock;
2923
2924 ret = open_related_ns(&net->ns, get_net_ns);
2925 goto unlock;
2926 }
2927
2928 ret = -EBADFD;
2929 if (!tun)
2930 goto unlock;
2931
2932 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2933
2934 ret = 0;
2935 switch (cmd) {
2936 case TUNGETIFF:
2937 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2938
2939 if (tfile->detached)
2940 ifr.ifr_flags |= IFF_DETACH_QUEUE;
2941 if (!tfile->socket.sk->sk_filter)
2942 ifr.ifr_flags |= IFF_NOFILTER;
2943
2944 if (copy_to_user(argp, &ifr, ifreq_len))
2945 ret = -EFAULT;
2946 break;
2947
2948 case TUNSETNOCSUM:
2949 /* Disable/Enable checksum */
2950
2951 /* [unimplemented] */
2952 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2953 arg ? "disabled" : "enabled");
2954 break;
2955
2956 case TUNSETPERSIST:
2957 /* Disable/Enable persist mode. Keep an extra reference to the
2958 * module to prevent the module being unprobed.
2959 */
2960 if (arg && !(tun->flags & IFF_PERSIST)) {
2961 tun->flags |= IFF_PERSIST;
2962 __module_get(THIS_MODULE);
2963 do_notify = true;
2964 }
2965 if (!arg && (tun->flags & IFF_PERSIST)) {
2966 tun->flags &= ~IFF_PERSIST;
2967 module_put(THIS_MODULE);
2968 do_notify = true;
2969 }
2970
2971 tun_debug(KERN_INFO, tun, "persist %s\n",
2972 arg ? "enabled" : "disabled");
2973 break;
2974
2975 case TUNSETOWNER:
2976 /* Set owner of the device */
2977 owner = make_kuid(current_user_ns(), arg);
2978 if (!uid_valid(owner)) {
2979 ret = -EINVAL;
2980 break;
2981 }
2982 tun->owner = owner;
2983 do_notify = true;
2984 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2985 from_kuid(&init_user_ns, tun->owner));
2986 break;
2987
2988 case TUNSETGROUP:
2989 /* Set group of the device */
2990 group = make_kgid(current_user_ns(), arg);
2991 if (!gid_valid(group)) {
2992 ret = -EINVAL;
2993 break;
2994 }
2995 tun->group = group;
2996 do_notify = true;
2997 tun_debug(KERN_INFO, tun, "group set to %u\n",
2998 from_kgid(&init_user_ns, tun->group));
2999 break;
3000
3001 case TUNSETLINK:
3002 /* Only allow setting the type when the interface is down */
3003 if (tun->dev->flags & IFF_UP) {
3004 tun_debug(KERN_INFO, tun,
3005 "Linktype set failed because interface is up\n");
3006 ret = -EBUSY;
3007 } else {
3008 tun->dev->type = (int) arg;
3009 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
3010 tun->dev->type);
3011 ret = 0;
3012 }
3013 break;
3014
3015#ifdef TUN_DEBUG
3016 case TUNSETDEBUG:
3017 tun->debug = arg;
3018 break;
3019#endif
3020 case TUNSETOFFLOAD:
3021 ret = set_offload(tun, arg);
3022 break;
3023
3024 case TUNSETTXFILTER:
3025 /* Can be set only for TAPs */
3026 ret = -EINVAL;
3027 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3028 break;
3029 ret = update_filter(&tun->txflt, (void __user *)arg);
3030 break;
3031
3032 case SIOCGIFHWADDR:
3033 /* Get hw address */
3034 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3035 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3036 if (copy_to_user(argp, &ifr, ifreq_len))
3037 ret = -EFAULT;
3038 break;
3039
3040 case SIOCSIFHWADDR:
3041 /* Set hw address */
3042 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
3043 ifr.ifr_hwaddr.sa_data);
3044
3045 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
3046 break;
3047
3048 case TUNGETSNDBUF:
3049 sndbuf = tfile->socket.sk->sk_sndbuf;
3050 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3051 ret = -EFAULT;
3052 break;
3053
3054 case TUNSETSNDBUF:
3055 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3056 ret = -EFAULT;
3057 break;
3058 }
3059 if (sndbuf <= 0) {
3060 ret = -EINVAL;
3061 break;
3062 }
3063
3064 tun->sndbuf = sndbuf;
3065 tun_set_sndbuf(tun);
3066 break;
3067
3068 case TUNGETVNETHDRSZ:
3069 vnet_hdr_sz = tun->vnet_hdr_sz;
3070 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3071 ret = -EFAULT;
3072 break;
3073
3074 case TUNSETVNETHDRSZ:
3075 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3076 ret = -EFAULT;
3077 break;
3078 }
3079 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3080 ret = -EINVAL;
3081 break;
3082 }
3083
3084 tun->vnet_hdr_sz = vnet_hdr_sz;
3085 break;
3086
3087 case TUNGETVNETLE:
3088 le = !!(tun->flags & TUN_VNET_LE);
3089 if (put_user(le, (int __user *)argp))
3090 ret = -EFAULT;
3091 break;
3092
3093 case TUNSETVNETLE:
3094 if (get_user(le, (int __user *)argp)) {
3095 ret = -EFAULT;
3096 break;
3097 }
3098 if (le)
3099 tun->flags |= TUN_VNET_LE;
3100 else
3101 tun->flags &= ~TUN_VNET_LE;
3102 break;
3103
3104 case TUNGETVNETBE:
3105 ret = tun_get_vnet_be(tun, argp);
3106 break;
3107
3108 case TUNSETVNETBE:
3109 ret = tun_set_vnet_be(tun, argp);
3110 break;
3111
3112 case TUNATTACHFILTER:
3113 /* Can be set only for TAPs */
3114 ret = -EINVAL;
3115 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3116 break;
3117 ret = -EFAULT;
3118 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3119 break;
3120
3121 ret = tun_attach_filter(tun);
3122 break;
3123
3124 case TUNDETACHFILTER:
3125 /* Can be set only for TAPs */
3126 ret = -EINVAL;
3127 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3128 break;
3129 ret = 0;
3130 tun_detach_filter(tun, tun->numqueues);
3131 break;
3132
3133 case TUNGETFILTER:
3134 ret = -EINVAL;
3135 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3136 break;
3137 ret = -EFAULT;
3138 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3139 break;
3140 ret = 0;
3141 break;
3142
3143 case TUNSETSTEERINGEBPF:
3144 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3145 break;
3146
3147 case TUNSETFILTEREBPF:
3148 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3149 break;
3150
3151 default:
3152 ret = -EINVAL;
3153 break;
3154 }
3155
3156 if (do_notify)
3157 netdev_state_change(tun->dev);
3158
3159unlock:
3160 rtnl_unlock();
3161 if (tun)
3162 tun_put(tun);
3163 return ret;
3164}
3165
3166static long tun_chr_ioctl(struct file *file,
3167 unsigned int cmd, unsigned long arg)
3168{
3169 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3170}
3171
3172#ifdef CONFIG_COMPAT
3173static long tun_chr_compat_ioctl(struct file *file,
3174 unsigned int cmd, unsigned long arg)
3175{
3176 switch (cmd) {
3177 case TUNSETIFF:
3178 case TUNGETIFF:
3179 case TUNSETTXFILTER:
3180 case TUNGETSNDBUF:
3181 case TUNSETSNDBUF:
3182 case SIOCGIFHWADDR:
3183 case SIOCSIFHWADDR:
3184 arg = (unsigned long)compat_ptr(arg);
3185 break;
3186 default:
3187 arg = (compat_ulong_t)arg;
3188 break;
3189 }
3190
3191 /*
3192 * compat_ifreq is shorter than ifreq, so we must not access beyond
3193 * the end of that structure. All fields that are used in this
3194 * driver are compatible though, we don't need to convert the
3195 * contents.
3196 */
3197 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3198}
3199#endif /* CONFIG_COMPAT */
3200
3201static int tun_chr_fasync(int fd, struct file *file, int on)
3202{
3203 struct tun_file *tfile = file->private_data;
3204 int ret;
3205
3206 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3207 goto out;
3208
3209 if (on) {
3210 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
3211 tfile->flags |= TUN_FASYNC;
3212 } else
3213 tfile->flags &= ~TUN_FASYNC;
3214 ret = 0;
3215out:
3216 return ret;
3217}
3218
3219static int tun_chr_open(struct inode *inode, struct file * file)
3220{
3221 struct net *net = current->nsproxy->net_ns;
3222 struct tun_file *tfile;
3223
3224 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
3225
3226 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3227 &tun_proto, 0);
3228 if (!tfile)
3229 return -ENOMEM;
3230 if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3231 sk_free(&tfile->sk);
3232 return -ENOMEM;
3233 }
3234
3235 RCU_INIT_POINTER(tfile->tun, NULL);
3236 tfile->flags = 0;
3237 tfile->ifindex = 0;
3238
3239 init_waitqueue_head(&tfile->wq.wait);
3240 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
3241
3242 tfile->socket.file = file;
3243 tfile->socket.ops = &tun_socket_ops;
3244
3245 sock_init_data(&tfile->socket, &tfile->sk);
3246
3247 tfile->sk.sk_write_space = tun_sock_write_space;
3248 tfile->sk.sk_sndbuf = INT_MAX;
3249
3250 file->private_data = tfile;
3251 INIT_LIST_HEAD(&tfile->next);
3252
3253 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3254
3255 return 0;
3256}
3257
3258static int tun_chr_close(struct inode *inode, struct file *file)
3259{
3260 struct tun_file *tfile = file->private_data;
3261
3262 tun_detach(tfile, true);
3263
3264 return 0;
3265}
3266
3267#ifdef CONFIG_PROC_FS
3268static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3269{
3270 struct tun_file *tfile = file->private_data;
3271 struct tun_struct *tun;
3272 struct ifreq ifr;
3273
3274 memset(&ifr, 0, sizeof(ifr));
3275
3276 rtnl_lock();
3277 tun = tun_get(tfile);
3278 if (tun)
3279 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
3280 rtnl_unlock();
3281
3282 if (tun)
3283 tun_put(tun);
3284
3285 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3286}
3287#endif
3288
3289static const struct file_operations tun_fops = {
3290 .owner = THIS_MODULE,
3291 .llseek = no_llseek,
3292 .read_iter = tun_chr_read_iter,
3293 .write_iter = tun_chr_write_iter,
3294 .poll = tun_chr_poll,
3295 .unlocked_ioctl = tun_chr_ioctl,
3296#ifdef CONFIG_COMPAT
3297 .compat_ioctl = tun_chr_compat_ioctl,
3298#endif
3299 .open = tun_chr_open,
3300 .release = tun_chr_close,
3301 .fasync = tun_chr_fasync,
3302#ifdef CONFIG_PROC_FS
3303 .show_fdinfo = tun_chr_show_fdinfo,
3304#endif
3305};
3306
3307static struct miscdevice tun_miscdev = {
3308 .minor = TUN_MINOR,
3309 .name = "tun",
3310 .nodename = "net/tun",
3311 .fops = &tun_fops,
3312};
3313
3314/* ethtool interface */
3315
3316static int tun_get_link_ksettings(struct net_device *dev,
3317 struct ethtool_link_ksettings *cmd)
3318{
3319 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3320 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3321 cmd->base.speed = SPEED_10;
3322 cmd->base.duplex = DUPLEX_FULL;
3323 cmd->base.port = PORT_TP;
3324 cmd->base.phy_address = 0;
3325 cmd->base.autoneg = AUTONEG_DISABLE;
3326 return 0;
3327}
3328
3329static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3330{
3331 struct tun_struct *tun = netdev_priv(dev);
3332
3333 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3334 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3335
3336 switch (tun->flags & TUN_TYPE_MASK) {
3337 case IFF_TUN:
3338 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3339 break;
3340 case IFF_TAP:
3341 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3342 break;
3343 }
3344}
3345
3346static u32 tun_get_msglevel(struct net_device *dev)
3347{
3348#ifdef TUN_DEBUG
3349 struct tun_struct *tun = netdev_priv(dev);
3350 return tun->debug;
3351#else
3352 return -EOPNOTSUPP;
3353#endif
3354}
3355
3356static void tun_set_msglevel(struct net_device *dev, u32 value)
3357{
3358#ifdef TUN_DEBUG
3359 struct tun_struct *tun = netdev_priv(dev);
3360 tun->debug = value;
3361#endif
3362}
3363
3364static int tun_get_coalesce(struct net_device *dev,
3365 struct ethtool_coalesce *ec)
3366{
3367 struct tun_struct *tun = netdev_priv(dev);
3368
3369 ec->rx_max_coalesced_frames = tun->rx_batched;
3370
3371 return 0;
3372}
3373
3374static int tun_set_coalesce(struct net_device *dev,
3375 struct ethtool_coalesce *ec)
3376{
3377 struct tun_struct *tun = netdev_priv(dev);
3378
3379 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3380 tun->rx_batched = NAPI_POLL_WEIGHT;
3381 else
3382 tun->rx_batched = ec->rx_max_coalesced_frames;
3383
3384 return 0;
3385}
3386
3387static const struct ethtool_ops tun_ethtool_ops = {
3388 .get_drvinfo = tun_get_drvinfo,
3389 .get_msglevel = tun_get_msglevel,
3390 .set_msglevel = tun_set_msglevel,
3391 .get_link = ethtool_op_get_link,
3392 .get_ts_info = ethtool_op_get_ts_info,
3393 .get_coalesce = tun_get_coalesce,
3394 .set_coalesce = tun_set_coalesce,
3395 .get_link_ksettings = tun_get_link_ksettings,
3396};
3397
3398static int tun_queue_resize(struct tun_struct *tun)
3399{
3400 struct net_device *dev = tun->dev;
3401 struct tun_file *tfile;
3402 struct ptr_ring **rings;
3403 int n = tun->numqueues + tun->numdisabled;
3404 int ret, i;
3405
3406 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3407 if (!rings)
3408 return -ENOMEM;
3409
3410 for (i = 0; i < tun->numqueues; i++) {
3411 tfile = rtnl_dereference(tun->tfiles[i]);
3412 rings[i] = &tfile->tx_ring;
3413 }
3414 list_for_each_entry(tfile, &tun->disabled, next)
3415 rings[i++] = &tfile->tx_ring;
3416
3417 ret = ptr_ring_resize_multiple(rings, n,
3418 dev->tx_queue_len, GFP_KERNEL,
3419 tun_ptr_free);
3420
3421 kfree(rings);
3422 return ret;
3423}
3424
3425static int tun_device_event(struct notifier_block *unused,
3426 unsigned long event, void *ptr)
3427{
3428 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3429 struct tun_struct *tun = netdev_priv(dev);
3430
3431 if (dev->rtnl_link_ops != &tun_link_ops)
3432 return NOTIFY_DONE;
3433
3434 switch (event) {
3435 case NETDEV_CHANGE_TX_QUEUE_LEN:
3436 if (tun_queue_resize(tun))
3437 return NOTIFY_BAD;
3438 break;
3439 default:
3440 break;
3441 }
3442
3443 return NOTIFY_DONE;
3444}
3445
3446static struct notifier_block tun_notifier_block __read_mostly = {
3447 .notifier_call = tun_device_event,
3448};
3449
3450static int __init tun_init(void)
3451{
3452 int ret = 0;
3453
3454 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3455
3456 ret = rtnl_link_register(&tun_link_ops);
3457 if (ret) {
3458 pr_err("Can't register link_ops\n");
3459 goto err_linkops;
3460 }
3461
3462 ret = misc_register(&tun_miscdev);
3463 if (ret) {
3464 pr_err("Can't register misc device %d\n", TUN_MINOR);
3465 goto err_misc;
3466 }
3467
3468 ret = register_netdevice_notifier(&tun_notifier_block);
3469 if (ret) {
3470 pr_err("Can't register netdevice notifier\n");
3471 goto err_notifier;
3472 }
3473
3474 return 0;
3475
3476err_notifier:
3477 misc_deregister(&tun_miscdev);
3478err_misc:
3479 rtnl_link_unregister(&tun_link_ops);
3480err_linkops:
3481 return ret;
3482}
3483
3484static void tun_cleanup(void)
3485{
3486 misc_deregister(&tun_miscdev);
3487 rtnl_link_unregister(&tun_link_ops);
3488 unregister_netdevice_notifier(&tun_notifier_block);
3489}
3490
3491/* Get an underlying socket object from tun file. Returns error unless file is
3492 * attached to a device. The returned object works like a packet socket, it
3493 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3494 * holding a reference to the file for as long as the socket is in use. */
3495struct socket *tun_get_socket(struct file *file)
3496{
3497 struct tun_file *tfile;
3498 if (file->f_op != &tun_fops)
3499 return ERR_PTR(-EINVAL);
3500 tfile = file->private_data;
3501 if (!tfile)
3502 return ERR_PTR(-EBADFD);
3503 return &tfile->socket;
3504}
3505EXPORT_SYMBOL_GPL(tun_get_socket);
3506
3507struct ptr_ring *tun_get_tx_ring(struct file *file)
3508{
3509 struct tun_file *tfile;
3510
3511 if (file->f_op != &tun_fops)
3512 return ERR_PTR(-EINVAL);
3513 tfile = file->private_data;
3514 if (!tfile)
3515 return ERR_PTR(-EBADFD);
3516 return &tfile->tx_ring;
3517}
3518EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3519
3520module_init(tun_init);
3521module_exit(tun_cleanup);
3522MODULE_DESCRIPTION(DRV_DESCRIPTION);
3523MODULE_AUTHOR(DRV_COPYRIGHT);
3524MODULE_LICENSE("GPL");
3525MODULE_ALIAS_MISCDEV(TUN_MINOR);
3526MODULE_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");