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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * TUN - Universal TUN/TAP device driver.
4 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
5 *
6 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
7 */
8
9/*
10 * Changes:
11 *
12 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
13 * Add TUNSETLINK ioctl to set the link encapsulation
14 *
15 * Mark Smith <markzzzsmith@yahoo.com.au>
16 * Use eth_random_addr() for tap MAC address.
17 *
18 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
19 * Fixes in packet dropping, queue length setting and queue wakeup.
20 * Increased default tx queue length.
21 * Added ethtool API.
22 * Minor cleanups
23 *
24 * Daniel Podlejski <underley@underley.eu.org>
25 * Modifications for 2.3.99-pre5 kernel.
26 */
27
28#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29
30#define DRV_NAME "tun"
31#define DRV_VERSION "1.6"
32#define DRV_DESCRIPTION "Universal TUN/TAP device driver"
33#define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
34
35#include <linux/module.h>
36#include <linux/errno.h>
37#include <linux/kernel.h>
38#include <linux/sched/signal.h>
39#include <linux/major.h>
40#include <linux/slab.h>
41#include <linux/poll.h>
42#include <linux/fcntl.h>
43#include <linux/init.h>
44#include <linux/skbuff.h>
45#include <linux/netdevice.h>
46#include <linux/etherdevice.h>
47#include <linux/miscdevice.h>
48#include <linux/ethtool.h>
49#include <linux/rtnetlink.h>
50#include <linux/compat.h>
51#include <linux/if.h>
52#include <linux/if_arp.h>
53#include <linux/if_ether.h>
54#include <linux/if_tun.h>
55#include <linux/if_vlan.h>
56#include <linux/crc32.h>
57#include <linux/nsproxy.h>
58#include <linux/virtio_net.h>
59#include <linux/rcupdate.h>
60#include <net/net_namespace.h>
61#include <net/netns/generic.h>
62#include <net/rtnetlink.h>
63#include <net/sock.h>
64#include <net/xdp.h>
65#include <linux/seq_file.h>
66#include <linux/uio.h>
67#include <linux/skb_array.h>
68#include <linux/bpf.h>
69#include <linux/bpf_trace.h>
70#include <linux/mutex.h>
71
72#include <linux/uaccess.h>
73#include <linux/proc_fs.h>
74
75static void tun_default_link_ksettings(struct net_device *dev,
76 struct ethtool_link_ksettings *cmd);
77
78/* Uncomment to enable debugging */
79/* #define TUN_DEBUG 1 */
80
81#ifdef TUN_DEBUG
82static int debug;
83
84#define tun_debug(level, tun, fmt, args...) \
85do { \
86 if (tun->debug) \
87 netdev_printk(level, tun->dev, fmt, ##args); \
88} while (0)
89#define DBG1(level, fmt, args...) \
90do { \
91 if (debug == 2) \
92 printk(level fmt, ##args); \
93} while (0)
94#else
95#define tun_debug(level, tun, fmt, args...) \
96do { \
97 if (0) \
98 netdev_printk(level, tun->dev, fmt, ##args); \
99} while (0)
100#define DBG1(level, fmt, args...) \
101do { \
102 if (0) \
103 printk(level fmt, ##args); \
104} while (0)
105#endif
106
107#define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
108
109/* TUN device flags */
110
111/* IFF_ATTACH_QUEUE is never stored in device flags,
112 * overload it to mean fasync when stored there.
113 */
114#define TUN_FASYNC IFF_ATTACH_QUEUE
115/* High bits in flags field are unused. */
116#define TUN_VNET_LE 0x80000000
117#define TUN_VNET_BE 0x40000000
118
119#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
120 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
121
122#define GOODCOPY_LEN 128
123
124#define FLT_EXACT_COUNT 8
125struct tap_filter {
126 unsigned int count; /* Number of addrs. Zero means disabled */
127 u32 mask[2]; /* Mask of the hashed addrs */
128 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
129};
130
131/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
132 * to max number of VCPUs in guest. */
133#define MAX_TAP_QUEUES 256
134#define MAX_TAP_FLOWS 4096
135
136#define TUN_FLOW_EXPIRE (3 * HZ)
137
138struct tun_pcpu_stats {
139 u64 rx_packets;
140 u64 rx_bytes;
141 u64 tx_packets;
142 u64 tx_bytes;
143 struct u64_stats_sync syncp;
144 u32 rx_dropped;
145 u32 tx_dropped;
146 u32 rx_frame_errors;
147};
148
149/* A tun_file connects an open character device to a tuntap netdevice. It
150 * also contains all socket related structures (except sock_fprog and tap_filter)
151 * to serve as one transmit queue for tuntap device. The sock_fprog and
152 * tap_filter were kept in tun_struct since they were used for filtering for the
153 * netdevice not for a specific queue (at least I didn't see the requirement for
154 * this).
155 *
156 * RCU usage:
157 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
158 * other can only be read while rcu_read_lock or rtnl_lock is held.
159 */
160struct tun_file {
161 struct sock sk;
162 struct socket socket;
163 struct tun_struct __rcu *tun;
164 struct fasync_struct *fasync;
165 /* only used for fasnyc */
166 unsigned int flags;
167 union {
168 u16 queue_index;
169 unsigned int ifindex;
170 };
171 struct napi_struct napi;
172 bool napi_enabled;
173 bool napi_frags_enabled;
174 struct mutex napi_mutex; /* Protects access to the above napi */
175 struct list_head next;
176 struct tun_struct *detached;
177 struct ptr_ring tx_ring;
178 struct xdp_rxq_info xdp_rxq;
179};
180
181struct tun_page {
182 struct page *page;
183 int count;
184};
185
186struct tun_flow_entry {
187 struct hlist_node hash_link;
188 struct rcu_head rcu;
189 struct tun_struct *tun;
190
191 u32 rxhash;
192 u32 rps_rxhash;
193 int queue_index;
194 unsigned long updated ____cacheline_aligned_in_smp;
195};
196
197#define TUN_NUM_FLOW_ENTRIES 1024
198#define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
199
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 struct ethtool_link_ksettings link_ksettings;
245};
246
247struct veth {
248 __be16 h_vlan_proto;
249 __be16 h_vlan_TCI;
250};
251
252bool tun_is_xdp_frame(void *ptr)
253{
254 return (unsigned long)ptr & TUN_XDP_FLAG;
255}
256EXPORT_SYMBOL(tun_is_xdp_frame);
257
258void *tun_xdp_to_ptr(void *ptr)
259{
260 return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
261}
262EXPORT_SYMBOL(tun_xdp_to_ptr);
263
264void *tun_ptr_to_xdp(void *ptr)
265{
266 return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
267}
268EXPORT_SYMBOL(tun_ptr_to_xdp);
269
270static int tun_napi_receive(struct napi_struct *napi, int budget)
271{
272 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
273 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
274 struct sk_buff_head process_queue;
275 struct sk_buff *skb;
276 int received = 0;
277
278 __skb_queue_head_init(&process_queue);
279
280 spin_lock(&queue->lock);
281 skb_queue_splice_tail_init(queue, &process_queue);
282 spin_unlock(&queue->lock);
283
284 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
285 napi_gro_receive(napi, skb);
286 ++received;
287 }
288
289 if (!skb_queue_empty(&process_queue)) {
290 spin_lock(&queue->lock);
291 skb_queue_splice(&process_queue, queue);
292 spin_unlock(&queue->lock);
293 }
294
295 return received;
296}
297
298static int tun_napi_poll(struct napi_struct *napi, int budget)
299{
300 unsigned int received;
301
302 received = tun_napi_receive(napi, budget);
303
304 if (received < budget)
305 napi_complete_done(napi, received);
306
307 return received;
308}
309
310static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
311 bool napi_en, bool napi_frags)
312{
313 tfile->napi_enabled = napi_en;
314 tfile->napi_frags_enabled = napi_en && napi_frags;
315 if (napi_en) {
316 netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
317 NAPI_POLL_WEIGHT);
318 napi_enable(&tfile->napi);
319 }
320}
321
322static void tun_napi_disable(struct tun_file *tfile)
323{
324 if (tfile->napi_enabled)
325 napi_disable(&tfile->napi);
326}
327
328static void tun_napi_del(struct tun_file *tfile)
329{
330 if (tfile->napi_enabled)
331 netif_napi_del(&tfile->napi);
332}
333
334static bool tun_napi_frags_enabled(const struct tun_file *tfile)
335{
336 return tfile->napi_frags_enabled;
337}
338
339#ifdef CONFIG_TUN_VNET_CROSS_LE
340static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
341{
342 return tun->flags & TUN_VNET_BE ? false :
343 virtio_legacy_is_little_endian();
344}
345
346static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
347{
348 int be = !!(tun->flags & TUN_VNET_BE);
349
350 if (put_user(be, argp))
351 return -EFAULT;
352
353 return 0;
354}
355
356static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
357{
358 int be;
359
360 if (get_user(be, argp))
361 return -EFAULT;
362
363 if (be)
364 tun->flags |= TUN_VNET_BE;
365 else
366 tun->flags &= ~TUN_VNET_BE;
367
368 return 0;
369}
370#else
371static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
372{
373 return virtio_legacy_is_little_endian();
374}
375
376static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
377{
378 return -EINVAL;
379}
380
381static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
382{
383 return -EINVAL;
384}
385#endif /* CONFIG_TUN_VNET_CROSS_LE */
386
387static inline bool tun_is_little_endian(struct tun_struct *tun)
388{
389 return tun->flags & TUN_VNET_LE ||
390 tun_legacy_is_little_endian(tun);
391}
392
393static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
394{
395 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
396}
397
398static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
399{
400 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
401}
402
403static inline u32 tun_hashfn(u32 rxhash)
404{
405 return rxhash & TUN_MASK_FLOW_ENTRIES;
406}
407
408static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
409{
410 struct tun_flow_entry *e;
411
412 hlist_for_each_entry_rcu(e, head, hash_link) {
413 if (e->rxhash == rxhash)
414 return e;
415 }
416 return NULL;
417}
418
419static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
420 struct hlist_head *head,
421 u32 rxhash, u16 queue_index)
422{
423 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
424
425 if (e) {
426 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
427 rxhash, queue_index);
428 e->updated = jiffies;
429 e->rxhash = rxhash;
430 e->rps_rxhash = 0;
431 e->queue_index = queue_index;
432 e->tun = tun;
433 hlist_add_head_rcu(&e->hash_link, head);
434 ++tun->flow_count;
435 }
436 return e;
437}
438
439static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
440{
441 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
442 e->rxhash, e->queue_index);
443 hlist_del_rcu(&e->hash_link);
444 kfree_rcu(e, rcu);
445 --tun->flow_count;
446}
447
448static void tun_flow_flush(struct tun_struct *tun)
449{
450 int i;
451
452 spin_lock_bh(&tun->lock);
453 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
454 struct tun_flow_entry *e;
455 struct hlist_node *n;
456
457 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
458 tun_flow_delete(tun, e);
459 }
460 spin_unlock_bh(&tun->lock);
461}
462
463static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
464{
465 int i;
466
467 spin_lock_bh(&tun->lock);
468 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
469 struct tun_flow_entry *e;
470 struct hlist_node *n;
471
472 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
473 if (e->queue_index == queue_index)
474 tun_flow_delete(tun, e);
475 }
476 }
477 spin_unlock_bh(&tun->lock);
478}
479
480static void tun_flow_cleanup(struct timer_list *t)
481{
482 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
483 unsigned long delay = tun->ageing_time;
484 unsigned long next_timer = jiffies + delay;
485 unsigned long count = 0;
486 int i;
487
488 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
489
490 spin_lock(&tun->lock);
491 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
492 struct tun_flow_entry *e;
493 struct hlist_node *n;
494
495 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
496 unsigned long this_timer;
497
498 this_timer = e->updated + delay;
499 if (time_before_eq(this_timer, jiffies)) {
500 tun_flow_delete(tun, e);
501 continue;
502 }
503 count++;
504 if (time_before(this_timer, next_timer))
505 next_timer = this_timer;
506 }
507 }
508
509 if (count)
510 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
511 spin_unlock(&tun->lock);
512}
513
514static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
515 struct tun_file *tfile)
516{
517 struct hlist_head *head;
518 struct tun_flow_entry *e;
519 unsigned long delay = tun->ageing_time;
520 u16 queue_index = tfile->queue_index;
521
522 head = &tun->flows[tun_hashfn(rxhash)];
523
524 rcu_read_lock();
525
526 e = tun_flow_find(head, rxhash);
527 if (likely(e)) {
528 /* TODO: keep queueing to old queue until it's empty? */
529 if (READ_ONCE(e->queue_index) != queue_index)
530 WRITE_ONCE(e->queue_index, queue_index);
531 if (e->updated != jiffies)
532 e->updated = jiffies;
533 sock_rps_record_flow_hash(e->rps_rxhash);
534 } else {
535 spin_lock_bh(&tun->lock);
536 if (!tun_flow_find(head, rxhash) &&
537 tun->flow_count < MAX_TAP_FLOWS)
538 tun_flow_create(tun, head, rxhash, queue_index);
539
540 if (!timer_pending(&tun->flow_gc_timer))
541 mod_timer(&tun->flow_gc_timer,
542 round_jiffies_up(jiffies + delay));
543 spin_unlock_bh(&tun->lock);
544 }
545
546 rcu_read_unlock();
547}
548
549/**
550 * Save the hash received in the stack receive path and update the
551 * flow_hash table accordingly.
552 */
553static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
554{
555 if (unlikely(e->rps_rxhash != hash))
556 e->rps_rxhash = hash;
557}
558
559/* We try to identify a flow through its rxhash. The reason that
560 * we do not check rxq no. is because some cards(e.g 82599), chooses
561 * the rxq based on the txq where the last packet of the flow comes. As
562 * the userspace application move between processors, we may get a
563 * different rxq no. here.
564 */
565static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
566{
567 struct tun_flow_entry *e;
568 u32 txq = 0;
569 u32 numqueues = 0;
570
571 numqueues = READ_ONCE(tun->numqueues);
572
573 txq = __skb_get_hash_symmetric(skb);
574 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
575 if (e) {
576 tun_flow_save_rps_rxhash(e, txq);
577 txq = e->queue_index;
578 } else {
579 /* use multiply and shift instead of expensive divide */
580 txq = ((u64)txq * numqueues) >> 32;
581 }
582
583 return txq;
584}
585
586static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
587{
588 struct tun_prog *prog;
589 u32 numqueues;
590 u16 ret = 0;
591
592 numqueues = READ_ONCE(tun->numqueues);
593 if (!numqueues)
594 return 0;
595
596 prog = rcu_dereference(tun->steering_prog);
597 if (prog)
598 ret = bpf_prog_run_clear_cb(prog->prog, skb);
599
600 return ret % numqueues;
601}
602
603static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
604 struct net_device *sb_dev)
605{
606 struct tun_struct *tun = netdev_priv(dev);
607 u16 ret;
608
609 rcu_read_lock();
610 if (rcu_dereference(tun->steering_prog))
611 ret = tun_ebpf_select_queue(tun, skb);
612 else
613 ret = tun_automq_select_queue(tun, skb);
614 rcu_read_unlock();
615
616 return ret;
617}
618
619static inline bool tun_not_capable(struct tun_struct *tun)
620{
621 const struct cred *cred = current_cred();
622 struct net *net = dev_net(tun->dev);
623
624 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
625 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
626 !ns_capable(net->user_ns, CAP_NET_ADMIN);
627}
628
629static void tun_set_real_num_queues(struct tun_struct *tun)
630{
631 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
632 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
633}
634
635static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
636{
637 tfile->detached = tun;
638 list_add_tail(&tfile->next, &tun->disabled);
639 ++tun->numdisabled;
640}
641
642static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
643{
644 struct tun_struct *tun = tfile->detached;
645
646 tfile->detached = NULL;
647 list_del_init(&tfile->next);
648 --tun->numdisabled;
649 return tun;
650}
651
652void tun_ptr_free(void *ptr)
653{
654 if (!ptr)
655 return;
656 if (tun_is_xdp_frame(ptr)) {
657 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
658
659 xdp_return_frame(xdpf);
660 } else {
661 __skb_array_destroy_skb(ptr);
662 }
663}
664EXPORT_SYMBOL_GPL(tun_ptr_free);
665
666static void tun_queue_purge(struct tun_file *tfile)
667{
668 void *ptr;
669
670 while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
671 tun_ptr_free(ptr);
672
673 skb_queue_purge(&tfile->sk.sk_write_queue);
674 skb_queue_purge(&tfile->sk.sk_error_queue);
675}
676
677static void __tun_detach(struct tun_file *tfile, bool clean)
678{
679 struct tun_file *ntfile;
680 struct tun_struct *tun;
681
682 tun = rtnl_dereference(tfile->tun);
683
684 if (tun && clean) {
685 tun_napi_disable(tfile);
686 tun_napi_del(tfile);
687 }
688
689 if (tun && !tfile->detached) {
690 u16 index = tfile->queue_index;
691 BUG_ON(index >= tun->numqueues);
692
693 rcu_assign_pointer(tun->tfiles[index],
694 tun->tfiles[tun->numqueues - 1]);
695 ntfile = rtnl_dereference(tun->tfiles[index]);
696 ntfile->queue_index = index;
697 rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
698 NULL);
699
700 --tun->numqueues;
701 if (clean) {
702 RCU_INIT_POINTER(tfile->tun, NULL);
703 sock_put(&tfile->sk);
704 } else
705 tun_disable_queue(tun, tfile);
706
707 synchronize_net();
708 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
709 /* Drop read queue */
710 tun_queue_purge(tfile);
711 tun_set_real_num_queues(tun);
712 } else if (tfile->detached && clean) {
713 tun = tun_enable_queue(tfile);
714 sock_put(&tfile->sk);
715 }
716
717 if (clean) {
718 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
719 netif_carrier_off(tun->dev);
720
721 if (!(tun->flags & IFF_PERSIST) &&
722 tun->dev->reg_state == NETREG_REGISTERED)
723 unregister_netdevice(tun->dev);
724 }
725 if (tun)
726 xdp_rxq_info_unreg(&tfile->xdp_rxq);
727 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
728 sock_put(&tfile->sk);
729 }
730}
731
732static void tun_detach(struct tun_file *tfile, bool clean)
733{
734 struct tun_struct *tun;
735 struct net_device *dev;
736
737 rtnl_lock();
738 tun = rtnl_dereference(tfile->tun);
739 dev = tun ? tun->dev : NULL;
740 __tun_detach(tfile, clean);
741 if (dev)
742 netdev_state_change(dev);
743 rtnl_unlock();
744}
745
746static void tun_detach_all(struct net_device *dev)
747{
748 struct tun_struct *tun = netdev_priv(dev);
749 struct tun_file *tfile, *tmp;
750 int i, n = tun->numqueues;
751
752 for (i = 0; i < n; i++) {
753 tfile = rtnl_dereference(tun->tfiles[i]);
754 BUG_ON(!tfile);
755 tun_napi_disable(tfile);
756 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
757 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
758 RCU_INIT_POINTER(tfile->tun, NULL);
759 --tun->numqueues;
760 }
761 list_for_each_entry(tfile, &tun->disabled, next) {
762 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
763 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
764 RCU_INIT_POINTER(tfile->tun, NULL);
765 }
766 BUG_ON(tun->numqueues != 0);
767
768 synchronize_net();
769 for (i = 0; i < n; i++) {
770 tfile = rtnl_dereference(tun->tfiles[i]);
771 tun_napi_del(tfile);
772 /* Drop read queue */
773 tun_queue_purge(tfile);
774 xdp_rxq_info_unreg(&tfile->xdp_rxq);
775 sock_put(&tfile->sk);
776 }
777 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
778 tun_enable_queue(tfile);
779 tun_queue_purge(tfile);
780 xdp_rxq_info_unreg(&tfile->xdp_rxq);
781 sock_put(&tfile->sk);
782 }
783 BUG_ON(tun->numdisabled != 0);
784
785 if (tun->flags & IFF_PERSIST)
786 module_put(THIS_MODULE);
787}
788
789static int tun_attach(struct tun_struct *tun, struct file *file,
790 bool skip_filter, bool napi, bool napi_frags,
791 bool publish_tun)
792{
793 struct tun_file *tfile = file->private_data;
794 struct net_device *dev = tun->dev;
795 int err;
796
797 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
798 if (err < 0)
799 goto out;
800
801 err = -EINVAL;
802 if (rtnl_dereference(tfile->tun) && !tfile->detached)
803 goto out;
804
805 err = -EBUSY;
806 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
807 goto out;
808
809 err = -E2BIG;
810 if (!tfile->detached &&
811 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
812 goto out;
813
814 err = 0;
815
816 /* Re-attach the filter to persist device */
817 if (!skip_filter && (tun->filter_attached == true)) {
818 lock_sock(tfile->socket.sk);
819 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
820 release_sock(tfile->socket.sk);
821 if (!err)
822 goto out;
823 }
824
825 if (!tfile->detached &&
826 ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
827 GFP_KERNEL, tun_ptr_free)) {
828 err = -ENOMEM;
829 goto out;
830 }
831
832 tfile->queue_index = tun->numqueues;
833 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
834
835 if (tfile->detached) {
836 /* Re-attach detached tfile, updating XDP queue_index */
837 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
838
839 if (tfile->xdp_rxq.queue_index != tfile->queue_index)
840 tfile->xdp_rxq.queue_index = tfile->queue_index;
841 } else {
842 /* Setup XDP RX-queue info, for new tfile getting attached */
843 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
844 tun->dev, tfile->queue_index);
845 if (err < 0)
846 goto out;
847 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
848 MEM_TYPE_PAGE_SHARED, NULL);
849 if (err < 0) {
850 xdp_rxq_info_unreg(&tfile->xdp_rxq);
851 goto out;
852 }
853 err = 0;
854 }
855
856 if (tfile->detached) {
857 tun_enable_queue(tfile);
858 } else {
859 sock_hold(&tfile->sk);
860 tun_napi_init(tun, tfile, napi, napi_frags);
861 }
862
863 if (rtnl_dereference(tun->xdp_prog))
864 sock_set_flag(&tfile->sk, SOCK_XDP);
865
866 /* device is allowed to go away first, so no need to hold extra
867 * refcnt.
868 */
869
870 /* Publish tfile->tun and tun->tfiles only after we've fully
871 * initialized tfile; otherwise we risk using half-initialized
872 * object.
873 */
874 if (publish_tun)
875 rcu_assign_pointer(tfile->tun, tun);
876 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
877 tun->numqueues++;
878 tun_set_real_num_queues(tun);
879out:
880 return err;
881}
882
883static struct tun_struct *tun_get(struct tun_file *tfile)
884{
885 struct tun_struct *tun;
886
887 rcu_read_lock();
888 tun = rcu_dereference(tfile->tun);
889 if (tun)
890 dev_hold(tun->dev);
891 rcu_read_unlock();
892
893 return tun;
894}
895
896static void tun_put(struct tun_struct *tun)
897{
898 dev_put(tun->dev);
899}
900
901/* TAP filtering */
902static void addr_hash_set(u32 *mask, const u8 *addr)
903{
904 int n = ether_crc(ETH_ALEN, addr) >> 26;
905 mask[n >> 5] |= (1 << (n & 31));
906}
907
908static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
909{
910 int n = ether_crc(ETH_ALEN, addr) >> 26;
911 return mask[n >> 5] & (1 << (n & 31));
912}
913
914static int update_filter(struct tap_filter *filter, void __user *arg)
915{
916 struct { u8 u[ETH_ALEN]; } *addr;
917 struct tun_filter uf;
918 int err, alen, n, nexact;
919
920 if (copy_from_user(&uf, arg, sizeof(uf)))
921 return -EFAULT;
922
923 if (!uf.count) {
924 /* Disabled */
925 filter->count = 0;
926 return 0;
927 }
928
929 alen = ETH_ALEN * uf.count;
930 addr = memdup_user(arg + sizeof(uf), alen);
931 if (IS_ERR(addr))
932 return PTR_ERR(addr);
933
934 /* The filter is updated without holding any locks. Which is
935 * perfectly safe. We disable it first and in the worst
936 * case we'll accept a few undesired packets. */
937 filter->count = 0;
938 wmb();
939
940 /* Use first set of addresses as an exact filter */
941 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
942 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
943
944 nexact = n;
945
946 /* Remaining multicast addresses are hashed,
947 * unicast will leave the filter disabled. */
948 memset(filter->mask, 0, sizeof(filter->mask));
949 for (; n < uf.count; n++) {
950 if (!is_multicast_ether_addr(addr[n].u)) {
951 err = 0; /* no filter */
952 goto free_addr;
953 }
954 addr_hash_set(filter->mask, addr[n].u);
955 }
956
957 /* For ALLMULTI just set the mask to all ones.
958 * This overrides the mask populated above. */
959 if ((uf.flags & TUN_FLT_ALLMULTI))
960 memset(filter->mask, ~0, sizeof(filter->mask));
961
962 /* Now enable the filter */
963 wmb();
964 filter->count = nexact;
965
966 /* Return the number of exact filters */
967 err = nexact;
968free_addr:
969 kfree(addr);
970 return err;
971}
972
973/* Returns: 0 - drop, !=0 - accept */
974static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
975{
976 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
977 * at this point. */
978 struct ethhdr *eh = (struct ethhdr *) skb->data;
979 int i;
980
981 /* Exact match */
982 for (i = 0; i < filter->count; i++)
983 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
984 return 1;
985
986 /* Inexact match (multicast only) */
987 if (is_multicast_ether_addr(eh->h_dest))
988 return addr_hash_test(filter->mask, eh->h_dest);
989
990 return 0;
991}
992
993/*
994 * Checks whether the packet is accepted or not.
995 * Returns: 0 - drop, !=0 - accept
996 */
997static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
998{
999 if (!filter->count)
1000 return 1;
1001
1002 return run_filter(filter, skb);
1003}
1004
1005/* Network device part of the driver */
1006
1007static const struct ethtool_ops tun_ethtool_ops;
1008
1009/* Net device detach from fd. */
1010static void tun_net_uninit(struct net_device *dev)
1011{
1012 tun_detach_all(dev);
1013}
1014
1015/* Net device open. */
1016static int tun_net_open(struct net_device *dev)
1017{
1018 netif_tx_start_all_queues(dev);
1019
1020 return 0;
1021}
1022
1023/* Net device close. */
1024static int tun_net_close(struct net_device *dev)
1025{
1026 netif_tx_stop_all_queues(dev);
1027 return 0;
1028}
1029
1030/* Net device start xmit */
1031static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1032{
1033#ifdef CONFIG_RPS
1034 if (tun->numqueues == 1 && static_branch_unlikely(&rps_needed)) {
1035 /* Select queue was not called for the skbuff, so we extract the
1036 * RPS hash and save it into the flow_table here.
1037 */
1038 struct tun_flow_entry *e;
1039 __u32 rxhash;
1040
1041 rxhash = __skb_get_hash_symmetric(skb);
1042 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
1043 if (e)
1044 tun_flow_save_rps_rxhash(e, rxhash);
1045 }
1046#endif
1047}
1048
1049static unsigned int run_ebpf_filter(struct tun_struct *tun,
1050 struct sk_buff *skb,
1051 int len)
1052{
1053 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1054
1055 if (prog)
1056 len = bpf_prog_run_clear_cb(prog->prog, skb);
1057
1058 return len;
1059}
1060
1061/* Net device start xmit */
1062static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1063{
1064 struct tun_struct *tun = netdev_priv(dev);
1065 int txq = skb->queue_mapping;
1066 struct tun_file *tfile;
1067 int len = skb->len;
1068
1069 rcu_read_lock();
1070 tfile = rcu_dereference(tun->tfiles[txq]);
1071
1072 /* Drop packet if interface is not attached */
1073 if (!tfile)
1074 goto drop;
1075
1076 if (!rcu_dereference(tun->steering_prog))
1077 tun_automq_xmit(tun, skb);
1078
1079 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
1080
1081 BUG_ON(!tfile);
1082
1083 /* Drop if the filter does not like it.
1084 * This is a noop if the filter is disabled.
1085 * Filter can be enabled only for the TAP devices. */
1086 if (!check_filter(&tun->txflt, skb))
1087 goto drop;
1088
1089 if (tfile->socket.sk->sk_filter &&
1090 sk_filter(tfile->socket.sk, skb))
1091 goto drop;
1092
1093 len = run_ebpf_filter(tun, skb, len);
1094 if (len == 0 || pskb_trim(skb, len))
1095 goto drop;
1096
1097 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1098 goto drop;
1099
1100 skb_tx_timestamp(skb);
1101
1102 /* Orphan the skb - required as we might hang on to it
1103 * for indefinite time.
1104 */
1105 skb_orphan(skb);
1106
1107 nf_reset_ct(skb);
1108
1109 if (ptr_ring_produce(&tfile->tx_ring, skb))
1110 goto drop;
1111
1112 /* Notify and wake up reader process */
1113 if (tfile->flags & TUN_FASYNC)
1114 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1115 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1116
1117 rcu_read_unlock();
1118 return NETDEV_TX_OK;
1119
1120drop:
1121 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1122 skb_tx_error(skb);
1123 kfree_skb(skb);
1124 rcu_read_unlock();
1125 return NET_XMIT_DROP;
1126}
1127
1128static void tun_net_mclist(struct net_device *dev)
1129{
1130 /*
1131 * This callback is supposed to deal with mc filter in
1132 * _rx_ path and has nothing to do with the _tx_ path.
1133 * In rx path we always accept everything userspace gives us.
1134 */
1135}
1136
1137static netdev_features_t tun_net_fix_features(struct net_device *dev,
1138 netdev_features_t features)
1139{
1140 struct tun_struct *tun = netdev_priv(dev);
1141
1142 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1143}
1144
1145static void tun_set_headroom(struct net_device *dev, int new_hr)
1146{
1147 struct tun_struct *tun = netdev_priv(dev);
1148
1149 if (new_hr < NET_SKB_PAD)
1150 new_hr = NET_SKB_PAD;
1151
1152 tun->align = new_hr;
1153}
1154
1155static void
1156tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1157{
1158 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1159 struct tun_struct *tun = netdev_priv(dev);
1160 struct tun_pcpu_stats *p;
1161 int i;
1162
1163 for_each_possible_cpu(i) {
1164 u64 rxpackets, rxbytes, txpackets, txbytes;
1165 unsigned int start;
1166
1167 p = per_cpu_ptr(tun->pcpu_stats, i);
1168 do {
1169 start = u64_stats_fetch_begin(&p->syncp);
1170 rxpackets = p->rx_packets;
1171 rxbytes = p->rx_bytes;
1172 txpackets = p->tx_packets;
1173 txbytes = p->tx_bytes;
1174 } while (u64_stats_fetch_retry(&p->syncp, start));
1175
1176 stats->rx_packets += rxpackets;
1177 stats->rx_bytes += rxbytes;
1178 stats->tx_packets += txpackets;
1179 stats->tx_bytes += txbytes;
1180
1181 /* u32 counters */
1182 rx_dropped += p->rx_dropped;
1183 rx_frame_errors += p->rx_frame_errors;
1184 tx_dropped += p->tx_dropped;
1185 }
1186 stats->rx_dropped = rx_dropped;
1187 stats->rx_frame_errors = rx_frame_errors;
1188 stats->tx_dropped = tx_dropped;
1189}
1190
1191static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1192 struct netlink_ext_ack *extack)
1193{
1194 struct tun_struct *tun = netdev_priv(dev);
1195 struct tun_file *tfile;
1196 struct bpf_prog *old_prog;
1197 int i;
1198
1199 old_prog = rtnl_dereference(tun->xdp_prog);
1200 rcu_assign_pointer(tun->xdp_prog, prog);
1201 if (old_prog)
1202 bpf_prog_put(old_prog);
1203
1204 for (i = 0; i < tun->numqueues; i++) {
1205 tfile = rtnl_dereference(tun->tfiles[i]);
1206 if (prog)
1207 sock_set_flag(&tfile->sk, SOCK_XDP);
1208 else
1209 sock_reset_flag(&tfile->sk, SOCK_XDP);
1210 }
1211 list_for_each_entry(tfile, &tun->disabled, next) {
1212 if (prog)
1213 sock_set_flag(&tfile->sk, SOCK_XDP);
1214 else
1215 sock_reset_flag(&tfile->sk, SOCK_XDP);
1216 }
1217
1218 return 0;
1219}
1220
1221static u32 tun_xdp_query(struct net_device *dev)
1222{
1223 struct tun_struct *tun = netdev_priv(dev);
1224 const struct bpf_prog *xdp_prog;
1225
1226 xdp_prog = rtnl_dereference(tun->xdp_prog);
1227 if (xdp_prog)
1228 return xdp_prog->aux->id;
1229
1230 return 0;
1231}
1232
1233static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1234{
1235 switch (xdp->command) {
1236 case XDP_SETUP_PROG:
1237 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1238 case XDP_QUERY_PROG:
1239 xdp->prog_id = tun_xdp_query(dev);
1240 return 0;
1241 default:
1242 return -EINVAL;
1243 }
1244}
1245
1246static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1247{
1248 if (new_carrier) {
1249 struct tun_struct *tun = netdev_priv(dev);
1250
1251 if (!tun->numqueues)
1252 return -EPERM;
1253
1254 netif_carrier_on(dev);
1255 } else {
1256 netif_carrier_off(dev);
1257 }
1258 return 0;
1259}
1260
1261static const struct net_device_ops tun_netdev_ops = {
1262 .ndo_uninit = tun_net_uninit,
1263 .ndo_open = tun_net_open,
1264 .ndo_stop = tun_net_close,
1265 .ndo_start_xmit = tun_net_xmit,
1266 .ndo_fix_features = tun_net_fix_features,
1267 .ndo_select_queue = tun_select_queue,
1268 .ndo_set_rx_headroom = tun_set_headroom,
1269 .ndo_get_stats64 = tun_net_get_stats64,
1270 .ndo_change_carrier = tun_net_change_carrier,
1271};
1272
1273static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1274{
1275 /* Notify and wake up reader process */
1276 if (tfile->flags & TUN_FASYNC)
1277 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1278 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1279}
1280
1281static int tun_xdp_xmit(struct net_device *dev, int n,
1282 struct xdp_frame **frames, u32 flags)
1283{
1284 struct tun_struct *tun = netdev_priv(dev);
1285 struct tun_file *tfile;
1286 u32 numqueues;
1287 int drops = 0;
1288 int cnt = n;
1289 int i;
1290
1291 if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1292 return -EINVAL;
1293
1294 rcu_read_lock();
1295
1296resample:
1297 numqueues = READ_ONCE(tun->numqueues);
1298 if (!numqueues) {
1299 rcu_read_unlock();
1300 return -ENXIO; /* Caller will free/return all frames */
1301 }
1302
1303 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1304 numqueues]);
1305 if (unlikely(!tfile))
1306 goto resample;
1307
1308 spin_lock(&tfile->tx_ring.producer_lock);
1309 for (i = 0; i < n; i++) {
1310 struct xdp_frame *xdp = frames[i];
1311 /* Encode the XDP flag into lowest bit for consumer to differ
1312 * XDP buffer from sk_buff.
1313 */
1314 void *frame = tun_xdp_to_ptr(xdp);
1315
1316 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1317 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1318 xdp_return_frame_rx_napi(xdp);
1319 drops++;
1320 }
1321 }
1322 spin_unlock(&tfile->tx_ring.producer_lock);
1323
1324 if (flags & XDP_XMIT_FLUSH)
1325 __tun_xdp_flush_tfile(tfile);
1326
1327 rcu_read_unlock();
1328 return cnt - drops;
1329}
1330
1331static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1332{
1333 struct xdp_frame *frame = convert_to_xdp_frame(xdp);
1334
1335 if (unlikely(!frame))
1336 return -EOVERFLOW;
1337
1338 return tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1339}
1340
1341static const struct net_device_ops tap_netdev_ops = {
1342 .ndo_uninit = tun_net_uninit,
1343 .ndo_open = tun_net_open,
1344 .ndo_stop = tun_net_close,
1345 .ndo_start_xmit = tun_net_xmit,
1346 .ndo_fix_features = tun_net_fix_features,
1347 .ndo_set_rx_mode = tun_net_mclist,
1348 .ndo_set_mac_address = eth_mac_addr,
1349 .ndo_validate_addr = eth_validate_addr,
1350 .ndo_select_queue = tun_select_queue,
1351 .ndo_features_check = passthru_features_check,
1352 .ndo_set_rx_headroom = tun_set_headroom,
1353 .ndo_get_stats64 = tun_net_get_stats64,
1354 .ndo_bpf = tun_xdp,
1355 .ndo_xdp_xmit = tun_xdp_xmit,
1356 .ndo_change_carrier = tun_net_change_carrier,
1357};
1358
1359static void tun_flow_init(struct tun_struct *tun)
1360{
1361 int i;
1362
1363 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1364 INIT_HLIST_HEAD(&tun->flows[i]);
1365
1366 tun->ageing_time = TUN_FLOW_EXPIRE;
1367 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1368 mod_timer(&tun->flow_gc_timer,
1369 round_jiffies_up(jiffies + tun->ageing_time));
1370}
1371
1372static void tun_flow_uninit(struct tun_struct *tun)
1373{
1374 del_timer_sync(&tun->flow_gc_timer);
1375 tun_flow_flush(tun);
1376}
1377
1378#define MIN_MTU 68
1379#define MAX_MTU 65535
1380
1381/* Initialize net device. */
1382static void tun_net_init(struct net_device *dev)
1383{
1384 struct tun_struct *tun = netdev_priv(dev);
1385
1386 switch (tun->flags & TUN_TYPE_MASK) {
1387 case IFF_TUN:
1388 dev->netdev_ops = &tun_netdev_ops;
1389
1390 /* Point-to-Point TUN Device */
1391 dev->hard_header_len = 0;
1392 dev->addr_len = 0;
1393 dev->mtu = 1500;
1394
1395 /* Zero header length */
1396 dev->type = ARPHRD_NONE;
1397 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1398 break;
1399
1400 case IFF_TAP:
1401 dev->netdev_ops = &tap_netdev_ops;
1402 /* Ethernet TAP Device */
1403 ether_setup(dev);
1404 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1405 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1406
1407 eth_hw_addr_random(dev);
1408
1409 break;
1410 }
1411
1412 dev->min_mtu = MIN_MTU;
1413 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1414}
1415
1416static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1417{
1418 struct sock *sk = tfile->socket.sk;
1419
1420 return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1421}
1422
1423/* Character device part */
1424
1425/* Poll */
1426static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1427{
1428 struct tun_file *tfile = file->private_data;
1429 struct tun_struct *tun = tun_get(tfile);
1430 struct sock *sk;
1431 __poll_t mask = 0;
1432
1433 if (!tun)
1434 return EPOLLERR;
1435
1436 sk = tfile->socket.sk;
1437
1438 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1439
1440 poll_wait(file, sk_sleep(sk), wait);
1441
1442 if (!ptr_ring_empty(&tfile->tx_ring))
1443 mask |= EPOLLIN | EPOLLRDNORM;
1444
1445 /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1446 * guarantee EPOLLOUT to be raised by either here or
1447 * tun_sock_write_space(). Then process could get notification
1448 * after it writes to a down device and meets -EIO.
1449 */
1450 if (tun_sock_writeable(tun, tfile) ||
1451 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1452 tun_sock_writeable(tun, tfile)))
1453 mask |= EPOLLOUT | EPOLLWRNORM;
1454
1455 if (tun->dev->reg_state != NETREG_REGISTERED)
1456 mask = EPOLLERR;
1457
1458 tun_put(tun);
1459 return mask;
1460}
1461
1462static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1463 size_t len,
1464 const struct iov_iter *it)
1465{
1466 struct sk_buff *skb;
1467 size_t linear;
1468 int err;
1469 int i;
1470
1471 if (it->nr_segs > MAX_SKB_FRAGS + 1)
1472 return ERR_PTR(-ENOMEM);
1473
1474 local_bh_disable();
1475 skb = napi_get_frags(&tfile->napi);
1476 local_bh_enable();
1477 if (!skb)
1478 return ERR_PTR(-ENOMEM);
1479
1480 linear = iov_iter_single_seg_count(it);
1481 err = __skb_grow(skb, linear);
1482 if (err)
1483 goto free;
1484
1485 skb->len = len;
1486 skb->data_len = len - linear;
1487 skb->truesize += skb->data_len;
1488
1489 for (i = 1; i < it->nr_segs; i++) {
1490 size_t fragsz = it->iov[i].iov_len;
1491 struct page *page;
1492 void *frag;
1493
1494 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1495 err = -EINVAL;
1496 goto free;
1497 }
1498 frag = netdev_alloc_frag(fragsz);
1499 if (!frag) {
1500 err = -ENOMEM;
1501 goto free;
1502 }
1503 page = virt_to_head_page(frag);
1504 skb_fill_page_desc(skb, i - 1, page,
1505 frag - page_address(page), fragsz);
1506 }
1507
1508 return skb;
1509free:
1510 /* frees skb and all frags allocated with napi_alloc_frag() */
1511 napi_free_frags(&tfile->napi);
1512 return ERR_PTR(err);
1513}
1514
1515/* prepad is the amount to reserve at front. len is length after that.
1516 * linear is a hint as to how much to copy (usually headers). */
1517static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1518 size_t prepad, size_t len,
1519 size_t linear, int noblock)
1520{
1521 struct sock *sk = tfile->socket.sk;
1522 struct sk_buff *skb;
1523 int err;
1524
1525 /* Under a page? Don't bother with paged skb. */
1526 if (prepad + len < PAGE_SIZE || !linear)
1527 linear = len;
1528
1529 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1530 &err, 0);
1531 if (!skb)
1532 return ERR_PTR(err);
1533
1534 skb_reserve(skb, prepad);
1535 skb_put(skb, linear);
1536 skb->data_len = len - linear;
1537 skb->len += len - linear;
1538
1539 return skb;
1540}
1541
1542static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1543 struct sk_buff *skb, int more)
1544{
1545 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1546 struct sk_buff_head process_queue;
1547 u32 rx_batched = tun->rx_batched;
1548 bool rcv = false;
1549
1550 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1551 local_bh_disable();
1552 skb_record_rx_queue(skb, tfile->queue_index);
1553 netif_receive_skb(skb);
1554 local_bh_enable();
1555 return;
1556 }
1557
1558 spin_lock(&queue->lock);
1559 if (!more || skb_queue_len(queue) == rx_batched) {
1560 __skb_queue_head_init(&process_queue);
1561 skb_queue_splice_tail_init(queue, &process_queue);
1562 rcv = true;
1563 } else {
1564 __skb_queue_tail(queue, skb);
1565 }
1566 spin_unlock(&queue->lock);
1567
1568 if (rcv) {
1569 struct sk_buff *nskb;
1570
1571 local_bh_disable();
1572 while ((nskb = __skb_dequeue(&process_queue))) {
1573 skb_record_rx_queue(nskb, tfile->queue_index);
1574 netif_receive_skb(nskb);
1575 }
1576 skb_record_rx_queue(skb, tfile->queue_index);
1577 netif_receive_skb(skb);
1578 local_bh_enable();
1579 }
1580}
1581
1582static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1583 int len, int noblock, bool zerocopy)
1584{
1585 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1586 return false;
1587
1588 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1589 return false;
1590
1591 if (!noblock)
1592 return false;
1593
1594 if (zerocopy)
1595 return false;
1596
1597 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1598 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1599 return false;
1600
1601 return true;
1602}
1603
1604static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
1605 struct page_frag *alloc_frag, char *buf,
1606 int buflen, int len, int pad)
1607{
1608 struct sk_buff *skb = build_skb(buf, buflen);
1609
1610 if (!skb)
1611 return ERR_PTR(-ENOMEM);
1612
1613 skb_reserve(skb, pad);
1614 skb_put(skb, len);
1615 skb_set_owner_w(skb, tfile->socket.sk);
1616
1617 get_page(alloc_frag->page);
1618 alloc_frag->offset += buflen;
1619
1620 return skb;
1621}
1622
1623static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1624 struct xdp_buff *xdp, u32 act)
1625{
1626 int err;
1627
1628 switch (act) {
1629 case XDP_REDIRECT:
1630 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1631 if (err)
1632 return err;
1633 break;
1634 case XDP_TX:
1635 err = tun_xdp_tx(tun->dev, xdp);
1636 if (err < 0)
1637 return err;
1638 break;
1639 case XDP_PASS:
1640 break;
1641 default:
1642 bpf_warn_invalid_xdp_action(act);
1643 /* fall through */
1644 case XDP_ABORTED:
1645 trace_xdp_exception(tun->dev, xdp_prog, act);
1646 /* fall through */
1647 case XDP_DROP:
1648 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1649 break;
1650 }
1651
1652 return act;
1653}
1654
1655static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1656 struct tun_file *tfile,
1657 struct iov_iter *from,
1658 struct virtio_net_hdr *hdr,
1659 int len, int *skb_xdp)
1660{
1661 struct page_frag *alloc_frag = ¤t->task_frag;
1662 struct bpf_prog *xdp_prog;
1663 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1664 char *buf;
1665 size_t copied;
1666 int pad = TUN_RX_PAD;
1667 int err = 0;
1668
1669 rcu_read_lock();
1670 xdp_prog = rcu_dereference(tun->xdp_prog);
1671 if (xdp_prog)
1672 pad += XDP_PACKET_HEADROOM;
1673 buflen += SKB_DATA_ALIGN(len + pad);
1674 rcu_read_unlock();
1675
1676 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1677 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1678 return ERR_PTR(-ENOMEM);
1679
1680 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1681 copied = copy_page_from_iter(alloc_frag->page,
1682 alloc_frag->offset + pad,
1683 len, from);
1684 if (copied != len)
1685 return ERR_PTR(-EFAULT);
1686
1687 /* There's a small window that XDP may be set after the check
1688 * of xdp_prog above, this should be rare and for simplicity
1689 * we do XDP on skb in case the headroom is not enough.
1690 */
1691 if (hdr->gso_type || !xdp_prog) {
1692 *skb_xdp = 1;
1693 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len,
1694 pad);
1695 }
1696
1697 *skb_xdp = 0;
1698
1699 local_bh_disable();
1700 rcu_read_lock();
1701 xdp_prog = rcu_dereference(tun->xdp_prog);
1702 if (xdp_prog) {
1703 struct xdp_buff xdp;
1704 u32 act;
1705
1706 xdp.data_hard_start = buf;
1707 xdp.data = buf + pad;
1708 xdp_set_data_meta_invalid(&xdp);
1709 xdp.data_end = xdp.data + len;
1710 xdp.rxq = &tfile->xdp_rxq;
1711
1712 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1713 if (act == XDP_REDIRECT || act == XDP_TX) {
1714 get_page(alloc_frag->page);
1715 alloc_frag->offset += buflen;
1716 }
1717 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1718 if (err < 0)
1719 goto err_xdp;
1720 if (err == XDP_REDIRECT)
1721 xdp_do_flush_map();
1722 if (err != XDP_PASS)
1723 goto out;
1724
1725 pad = xdp.data - xdp.data_hard_start;
1726 len = xdp.data_end - xdp.data;
1727 }
1728 rcu_read_unlock();
1729 local_bh_enable();
1730
1731 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1732
1733err_xdp:
1734 put_page(alloc_frag->page);
1735out:
1736 rcu_read_unlock();
1737 local_bh_enable();
1738 return NULL;
1739}
1740
1741/* Get packet from user space buffer */
1742static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1743 void *msg_control, struct iov_iter *from,
1744 int noblock, bool more)
1745{
1746 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1747 struct sk_buff *skb;
1748 size_t total_len = iov_iter_count(from);
1749 size_t len = total_len, align = tun->align, linear;
1750 struct virtio_net_hdr gso = { 0 };
1751 struct tun_pcpu_stats *stats;
1752 int good_linear;
1753 int copylen;
1754 bool zerocopy = false;
1755 int err;
1756 u32 rxhash = 0;
1757 int skb_xdp = 1;
1758 bool frags = tun_napi_frags_enabled(tfile);
1759
1760 if (!(tun->flags & IFF_NO_PI)) {
1761 if (len < sizeof(pi))
1762 return -EINVAL;
1763 len -= sizeof(pi);
1764
1765 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1766 return -EFAULT;
1767 }
1768
1769 if (tun->flags & IFF_VNET_HDR) {
1770 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1771
1772 if (len < vnet_hdr_sz)
1773 return -EINVAL;
1774 len -= vnet_hdr_sz;
1775
1776 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1777 return -EFAULT;
1778
1779 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1780 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1781 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1782
1783 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1784 return -EINVAL;
1785 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1786 }
1787
1788 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1789 align += NET_IP_ALIGN;
1790 if (unlikely(len < ETH_HLEN ||
1791 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1792 return -EINVAL;
1793 }
1794
1795 good_linear = SKB_MAX_HEAD(align);
1796
1797 if (msg_control) {
1798 struct iov_iter i = *from;
1799
1800 /* There are 256 bytes to be copied in skb, so there is
1801 * enough room for skb expand head in case it is used.
1802 * The rest of the buffer is mapped from userspace.
1803 */
1804 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1805 if (copylen > good_linear)
1806 copylen = good_linear;
1807 linear = copylen;
1808 iov_iter_advance(&i, copylen);
1809 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1810 zerocopy = true;
1811 }
1812
1813 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1814 /* For the packet that is not easy to be processed
1815 * (e.g gso or jumbo packet), we will do it at after
1816 * skb was created with generic XDP routine.
1817 */
1818 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1819 if (IS_ERR(skb)) {
1820 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1821 return PTR_ERR(skb);
1822 }
1823 if (!skb)
1824 return total_len;
1825 } else {
1826 if (!zerocopy) {
1827 copylen = len;
1828 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1829 linear = good_linear;
1830 else
1831 linear = tun16_to_cpu(tun, gso.hdr_len);
1832 }
1833
1834 if (frags) {
1835 mutex_lock(&tfile->napi_mutex);
1836 skb = tun_napi_alloc_frags(tfile, copylen, from);
1837 /* tun_napi_alloc_frags() enforces a layout for the skb.
1838 * If zerocopy is enabled, then this layout will be
1839 * overwritten by zerocopy_sg_from_iter().
1840 */
1841 zerocopy = false;
1842 } else {
1843 skb = tun_alloc_skb(tfile, align, copylen, linear,
1844 noblock);
1845 }
1846
1847 if (IS_ERR(skb)) {
1848 if (PTR_ERR(skb) != -EAGAIN)
1849 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1850 if (frags)
1851 mutex_unlock(&tfile->napi_mutex);
1852 return PTR_ERR(skb);
1853 }
1854
1855 if (zerocopy)
1856 err = zerocopy_sg_from_iter(skb, from);
1857 else
1858 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1859
1860 if (err) {
1861 err = -EFAULT;
1862drop:
1863 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1864 kfree_skb(skb);
1865 if (frags) {
1866 tfile->napi.skb = NULL;
1867 mutex_unlock(&tfile->napi_mutex);
1868 }
1869
1870 return err;
1871 }
1872 }
1873
1874 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1875 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1876 kfree_skb(skb);
1877 if (frags) {
1878 tfile->napi.skb = NULL;
1879 mutex_unlock(&tfile->napi_mutex);
1880 }
1881
1882 return -EINVAL;
1883 }
1884
1885 switch (tun->flags & TUN_TYPE_MASK) {
1886 case IFF_TUN:
1887 if (tun->flags & IFF_NO_PI) {
1888 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1889
1890 switch (ip_version) {
1891 case 4:
1892 pi.proto = htons(ETH_P_IP);
1893 break;
1894 case 6:
1895 pi.proto = htons(ETH_P_IPV6);
1896 break;
1897 default:
1898 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1899 kfree_skb(skb);
1900 return -EINVAL;
1901 }
1902 }
1903
1904 skb_reset_mac_header(skb);
1905 skb->protocol = pi.proto;
1906 skb->dev = tun->dev;
1907 break;
1908 case IFF_TAP:
1909 if (!frags)
1910 skb->protocol = eth_type_trans(skb, tun->dev);
1911 break;
1912 }
1913
1914 /* copy skb_ubuf_info for callback when skb has no error */
1915 if (zerocopy) {
1916 skb_shinfo(skb)->destructor_arg = msg_control;
1917 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1918 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1919 } else if (msg_control) {
1920 struct ubuf_info *uarg = msg_control;
1921 uarg->callback(uarg, false);
1922 }
1923
1924 skb_reset_network_header(skb);
1925 skb_probe_transport_header(skb);
1926
1927 if (skb_xdp) {
1928 struct bpf_prog *xdp_prog;
1929 int ret;
1930
1931 local_bh_disable();
1932 rcu_read_lock();
1933 xdp_prog = rcu_dereference(tun->xdp_prog);
1934 if (xdp_prog) {
1935 ret = do_xdp_generic(xdp_prog, skb);
1936 if (ret != XDP_PASS) {
1937 rcu_read_unlock();
1938 local_bh_enable();
1939 return total_len;
1940 }
1941 }
1942 rcu_read_unlock();
1943 local_bh_enable();
1944 }
1945
1946 /* Compute the costly rx hash only if needed for flow updates.
1947 * We may get a very small possibility of OOO during switching, not
1948 * worth to optimize.
1949 */
1950 if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1951 !tfile->detached)
1952 rxhash = __skb_get_hash_symmetric(skb);
1953
1954 rcu_read_lock();
1955 if (unlikely(!(tun->dev->flags & IFF_UP))) {
1956 err = -EIO;
1957 rcu_read_unlock();
1958 goto drop;
1959 }
1960
1961 if (frags) {
1962 /* Exercise flow dissector code path. */
1963 u32 headlen = eth_get_headlen(tun->dev, skb->data,
1964 skb_headlen(skb));
1965
1966 if (unlikely(headlen > skb_headlen(skb))) {
1967 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1968 napi_free_frags(&tfile->napi);
1969 rcu_read_unlock();
1970 mutex_unlock(&tfile->napi_mutex);
1971 WARN_ON(1);
1972 return -ENOMEM;
1973 }
1974
1975 local_bh_disable();
1976 napi_gro_frags(&tfile->napi);
1977 local_bh_enable();
1978 mutex_unlock(&tfile->napi_mutex);
1979 } else if (tfile->napi_enabled) {
1980 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1981 int queue_len;
1982
1983 spin_lock_bh(&queue->lock);
1984 __skb_queue_tail(queue, skb);
1985 queue_len = skb_queue_len(queue);
1986 spin_unlock(&queue->lock);
1987
1988 if (!more || queue_len > NAPI_POLL_WEIGHT)
1989 napi_schedule(&tfile->napi);
1990
1991 local_bh_enable();
1992 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1993 tun_rx_batched(tun, tfile, skb, more);
1994 } else {
1995 netif_rx_ni(skb);
1996 }
1997 rcu_read_unlock();
1998
1999 stats = get_cpu_ptr(tun->pcpu_stats);
2000 u64_stats_update_begin(&stats->syncp);
2001 stats->rx_packets++;
2002 stats->rx_bytes += len;
2003 u64_stats_update_end(&stats->syncp);
2004 put_cpu_ptr(stats);
2005
2006 if (rxhash)
2007 tun_flow_update(tun, rxhash, tfile);
2008
2009 return total_len;
2010}
2011
2012static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
2013{
2014 struct file *file = iocb->ki_filp;
2015 struct tun_file *tfile = file->private_data;
2016 struct tun_struct *tun = tun_get(tfile);
2017 ssize_t result;
2018
2019 if (!tun)
2020 return -EBADFD;
2021
2022 result = tun_get_user(tun, tfile, NULL, from,
2023 file->f_flags & O_NONBLOCK, false);
2024
2025 tun_put(tun);
2026 return result;
2027}
2028
2029static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2030 struct tun_file *tfile,
2031 struct xdp_frame *xdp_frame,
2032 struct iov_iter *iter)
2033{
2034 int vnet_hdr_sz = 0;
2035 size_t size = xdp_frame->len;
2036 struct tun_pcpu_stats *stats;
2037 size_t ret;
2038
2039 if (tun->flags & IFF_VNET_HDR) {
2040 struct virtio_net_hdr gso = { 0 };
2041
2042 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2043 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2044 return -EINVAL;
2045 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2046 sizeof(gso)))
2047 return -EFAULT;
2048 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2049 }
2050
2051 ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2052
2053 stats = get_cpu_ptr(tun->pcpu_stats);
2054 u64_stats_update_begin(&stats->syncp);
2055 stats->tx_packets++;
2056 stats->tx_bytes += ret;
2057 u64_stats_update_end(&stats->syncp);
2058 put_cpu_ptr(tun->pcpu_stats);
2059
2060 return ret;
2061}
2062
2063/* Put packet to the user space buffer */
2064static ssize_t tun_put_user(struct tun_struct *tun,
2065 struct tun_file *tfile,
2066 struct sk_buff *skb,
2067 struct iov_iter *iter)
2068{
2069 struct tun_pi pi = { 0, skb->protocol };
2070 struct tun_pcpu_stats *stats;
2071 ssize_t total;
2072 int vlan_offset = 0;
2073 int vlan_hlen = 0;
2074 int vnet_hdr_sz = 0;
2075
2076 if (skb_vlan_tag_present(skb))
2077 vlan_hlen = VLAN_HLEN;
2078
2079 if (tun->flags & IFF_VNET_HDR)
2080 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2081
2082 total = skb->len + vlan_hlen + vnet_hdr_sz;
2083
2084 if (!(tun->flags & IFF_NO_PI)) {
2085 if (iov_iter_count(iter) < sizeof(pi))
2086 return -EINVAL;
2087
2088 total += sizeof(pi);
2089 if (iov_iter_count(iter) < total) {
2090 /* Packet will be striped */
2091 pi.flags |= TUN_PKT_STRIP;
2092 }
2093
2094 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2095 return -EFAULT;
2096 }
2097
2098 if (vnet_hdr_sz) {
2099 struct virtio_net_hdr gso;
2100
2101 if (iov_iter_count(iter) < vnet_hdr_sz)
2102 return -EINVAL;
2103
2104 if (virtio_net_hdr_from_skb(skb, &gso,
2105 tun_is_little_endian(tun), true,
2106 vlan_hlen)) {
2107 struct skb_shared_info *sinfo = skb_shinfo(skb);
2108 pr_err("unexpected GSO type: "
2109 "0x%x, gso_size %d, hdr_len %d\n",
2110 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2111 tun16_to_cpu(tun, gso.hdr_len));
2112 print_hex_dump(KERN_ERR, "tun: ",
2113 DUMP_PREFIX_NONE,
2114 16, 1, skb->head,
2115 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2116 WARN_ON_ONCE(1);
2117 return -EINVAL;
2118 }
2119
2120 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2121 return -EFAULT;
2122
2123 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2124 }
2125
2126 if (vlan_hlen) {
2127 int ret;
2128 struct veth veth;
2129
2130 veth.h_vlan_proto = skb->vlan_proto;
2131 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2132
2133 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2134
2135 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2136 if (ret || !iov_iter_count(iter))
2137 goto done;
2138
2139 ret = copy_to_iter(&veth, sizeof(veth), iter);
2140 if (ret != sizeof(veth) || !iov_iter_count(iter))
2141 goto done;
2142 }
2143
2144 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2145
2146done:
2147 /* caller is in process context, */
2148 stats = get_cpu_ptr(tun->pcpu_stats);
2149 u64_stats_update_begin(&stats->syncp);
2150 stats->tx_packets++;
2151 stats->tx_bytes += skb->len + vlan_hlen;
2152 u64_stats_update_end(&stats->syncp);
2153 put_cpu_ptr(tun->pcpu_stats);
2154
2155 return total;
2156}
2157
2158static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2159{
2160 DECLARE_WAITQUEUE(wait, current);
2161 void *ptr = NULL;
2162 int error = 0;
2163
2164 ptr = ptr_ring_consume(&tfile->tx_ring);
2165 if (ptr)
2166 goto out;
2167 if (noblock) {
2168 error = -EAGAIN;
2169 goto out;
2170 }
2171
2172 add_wait_queue(&tfile->socket.wq.wait, &wait);
2173
2174 while (1) {
2175 set_current_state(TASK_INTERRUPTIBLE);
2176 ptr = ptr_ring_consume(&tfile->tx_ring);
2177 if (ptr)
2178 break;
2179 if (signal_pending(current)) {
2180 error = -ERESTARTSYS;
2181 break;
2182 }
2183 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2184 error = -EFAULT;
2185 break;
2186 }
2187
2188 schedule();
2189 }
2190
2191 __set_current_state(TASK_RUNNING);
2192 remove_wait_queue(&tfile->socket.wq.wait, &wait);
2193
2194out:
2195 *err = error;
2196 return ptr;
2197}
2198
2199static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2200 struct iov_iter *to,
2201 int noblock, void *ptr)
2202{
2203 ssize_t ret;
2204 int err;
2205
2206 tun_debug(KERN_INFO, tun, "tun_do_read\n");
2207
2208 if (!iov_iter_count(to)) {
2209 tun_ptr_free(ptr);
2210 return 0;
2211 }
2212
2213 if (!ptr) {
2214 /* Read frames from ring */
2215 ptr = tun_ring_recv(tfile, noblock, &err);
2216 if (!ptr)
2217 return err;
2218 }
2219
2220 if (tun_is_xdp_frame(ptr)) {
2221 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2222
2223 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2224 xdp_return_frame(xdpf);
2225 } else {
2226 struct sk_buff *skb = ptr;
2227
2228 ret = tun_put_user(tun, tfile, skb, to);
2229 if (unlikely(ret < 0))
2230 kfree_skb(skb);
2231 else
2232 consume_skb(skb);
2233 }
2234
2235 return ret;
2236}
2237
2238static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2239{
2240 struct file *file = iocb->ki_filp;
2241 struct tun_file *tfile = file->private_data;
2242 struct tun_struct *tun = tun_get(tfile);
2243 ssize_t len = iov_iter_count(to), ret;
2244
2245 if (!tun)
2246 return -EBADFD;
2247 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2248 ret = min_t(ssize_t, ret, len);
2249 if (ret > 0)
2250 iocb->ki_pos = ret;
2251 tun_put(tun);
2252 return ret;
2253}
2254
2255static void tun_prog_free(struct rcu_head *rcu)
2256{
2257 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2258
2259 bpf_prog_destroy(prog->prog);
2260 kfree(prog);
2261}
2262
2263static int __tun_set_ebpf(struct tun_struct *tun,
2264 struct tun_prog __rcu **prog_p,
2265 struct bpf_prog *prog)
2266{
2267 struct tun_prog *old, *new = NULL;
2268
2269 if (prog) {
2270 new = kmalloc(sizeof(*new), GFP_KERNEL);
2271 if (!new)
2272 return -ENOMEM;
2273 new->prog = prog;
2274 }
2275
2276 spin_lock_bh(&tun->lock);
2277 old = rcu_dereference_protected(*prog_p,
2278 lockdep_is_held(&tun->lock));
2279 rcu_assign_pointer(*prog_p, new);
2280 spin_unlock_bh(&tun->lock);
2281
2282 if (old)
2283 call_rcu(&old->rcu, tun_prog_free);
2284
2285 return 0;
2286}
2287
2288static void tun_free_netdev(struct net_device *dev)
2289{
2290 struct tun_struct *tun = netdev_priv(dev);
2291
2292 BUG_ON(!(list_empty(&tun->disabled)));
2293 free_percpu(tun->pcpu_stats);
2294 tun_flow_uninit(tun);
2295 security_tun_dev_free_security(tun->security);
2296 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2297 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2298}
2299
2300static void tun_setup(struct net_device *dev)
2301{
2302 struct tun_struct *tun = netdev_priv(dev);
2303
2304 tun->owner = INVALID_UID;
2305 tun->group = INVALID_GID;
2306 tun_default_link_ksettings(dev, &tun->link_ksettings);
2307
2308 dev->ethtool_ops = &tun_ethtool_ops;
2309 dev->needs_free_netdev = true;
2310 dev->priv_destructor = tun_free_netdev;
2311 /* We prefer our own queue length */
2312 dev->tx_queue_len = TUN_READQ_SIZE;
2313}
2314
2315/* Trivial set of netlink ops to allow deleting tun or tap
2316 * device with netlink.
2317 */
2318static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2319 struct netlink_ext_ack *extack)
2320{
2321 NL_SET_ERR_MSG(extack,
2322 "tun/tap creation via rtnetlink is not supported.");
2323 return -EOPNOTSUPP;
2324}
2325
2326static size_t tun_get_size(const struct net_device *dev)
2327{
2328 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2329 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2330
2331 return nla_total_size(sizeof(uid_t)) + /* OWNER */
2332 nla_total_size(sizeof(gid_t)) + /* GROUP */
2333 nla_total_size(sizeof(u8)) + /* TYPE */
2334 nla_total_size(sizeof(u8)) + /* PI */
2335 nla_total_size(sizeof(u8)) + /* VNET_HDR */
2336 nla_total_size(sizeof(u8)) + /* PERSIST */
2337 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2338 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2339 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2340 0;
2341}
2342
2343static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2344{
2345 struct tun_struct *tun = netdev_priv(dev);
2346
2347 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2348 goto nla_put_failure;
2349 if (uid_valid(tun->owner) &&
2350 nla_put_u32(skb, IFLA_TUN_OWNER,
2351 from_kuid_munged(current_user_ns(), tun->owner)))
2352 goto nla_put_failure;
2353 if (gid_valid(tun->group) &&
2354 nla_put_u32(skb, IFLA_TUN_GROUP,
2355 from_kgid_munged(current_user_ns(), tun->group)))
2356 goto nla_put_failure;
2357 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2358 goto nla_put_failure;
2359 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2360 goto nla_put_failure;
2361 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2362 goto nla_put_failure;
2363 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2364 !!(tun->flags & IFF_MULTI_QUEUE)))
2365 goto nla_put_failure;
2366 if (tun->flags & IFF_MULTI_QUEUE) {
2367 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2368 goto nla_put_failure;
2369 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2370 tun->numdisabled))
2371 goto nla_put_failure;
2372 }
2373
2374 return 0;
2375
2376nla_put_failure:
2377 return -EMSGSIZE;
2378}
2379
2380static struct rtnl_link_ops tun_link_ops __read_mostly = {
2381 .kind = DRV_NAME,
2382 .priv_size = sizeof(struct tun_struct),
2383 .setup = tun_setup,
2384 .validate = tun_validate,
2385 .get_size = tun_get_size,
2386 .fill_info = tun_fill_info,
2387};
2388
2389static void tun_sock_write_space(struct sock *sk)
2390{
2391 struct tun_file *tfile;
2392 wait_queue_head_t *wqueue;
2393
2394 if (!sock_writeable(sk))
2395 return;
2396
2397 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2398 return;
2399
2400 wqueue = sk_sleep(sk);
2401 if (wqueue && waitqueue_active(wqueue))
2402 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2403 EPOLLWRNORM | EPOLLWRBAND);
2404
2405 tfile = container_of(sk, struct tun_file, sk);
2406 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2407}
2408
2409static void tun_put_page(struct tun_page *tpage)
2410{
2411 if (tpage->page)
2412 __page_frag_cache_drain(tpage->page, tpage->count);
2413}
2414
2415static int tun_xdp_one(struct tun_struct *tun,
2416 struct tun_file *tfile,
2417 struct xdp_buff *xdp, int *flush,
2418 struct tun_page *tpage)
2419{
2420 unsigned int datasize = xdp->data_end - xdp->data;
2421 struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2422 struct virtio_net_hdr *gso = &hdr->gso;
2423 struct tun_pcpu_stats *stats;
2424 struct bpf_prog *xdp_prog;
2425 struct sk_buff *skb = NULL;
2426 u32 rxhash = 0, act;
2427 int buflen = hdr->buflen;
2428 int err = 0;
2429 bool skb_xdp = false;
2430 struct page *page;
2431
2432 xdp_prog = rcu_dereference(tun->xdp_prog);
2433 if (xdp_prog) {
2434 if (gso->gso_type) {
2435 skb_xdp = true;
2436 goto build;
2437 }
2438 xdp_set_data_meta_invalid(xdp);
2439 xdp->rxq = &tfile->xdp_rxq;
2440
2441 act = bpf_prog_run_xdp(xdp_prog, xdp);
2442 err = tun_xdp_act(tun, xdp_prog, xdp, act);
2443 if (err < 0) {
2444 put_page(virt_to_head_page(xdp->data));
2445 return err;
2446 }
2447
2448 switch (err) {
2449 case XDP_REDIRECT:
2450 *flush = true;
2451 /* fall through */
2452 case XDP_TX:
2453 return 0;
2454 case XDP_PASS:
2455 break;
2456 default:
2457 page = virt_to_head_page(xdp->data);
2458 if (tpage->page == page) {
2459 ++tpage->count;
2460 } else {
2461 tun_put_page(tpage);
2462 tpage->page = page;
2463 tpage->count = 1;
2464 }
2465 return 0;
2466 }
2467 }
2468
2469build:
2470 skb = build_skb(xdp->data_hard_start, buflen);
2471 if (!skb) {
2472 err = -ENOMEM;
2473 goto out;
2474 }
2475
2476 skb_reserve(skb, xdp->data - xdp->data_hard_start);
2477 skb_put(skb, xdp->data_end - xdp->data);
2478
2479 if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2480 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
2481 kfree_skb(skb);
2482 err = -EINVAL;
2483 goto out;
2484 }
2485
2486 skb->protocol = eth_type_trans(skb, tun->dev);
2487 skb_reset_network_header(skb);
2488 skb_probe_transport_header(skb);
2489
2490 if (skb_xdp) {
2491 err = do_xdp_generic(xdp_prog, skb);
2492 if (err != XDP_PASS)
2493 goto out;
2494 }
2495
2496 if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2497 !tfile->detached)
2498 rxhash = __skb_get_hash_symmetric(skb);
2499
2500 skb_record_rx_queue(skb, tfile->queue_index);
2501 netif_receive_skb(skb);
2502
2503 /* No need for get_cpu_ptr() here since this function is
2504 * always called with bh disabled
2505 */
2506 stats = this_cpu_ptr(tun->pcpu_stats);
2507 u64_stats_update_begin(&stats->syncp);
2508 stats->rx_packets++;
2509 stats->rx_bytes += datasize;
2510 u64_stats_update_end(&stats->syncp);
2511
2512 if (rxhash)
2513 tun_flow_update(tun, rxhash, tfile);
2514
2515out:
2516 return err;
2517}
2518
2519static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2520{
2521 int ret, i;
2522 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2523 struct tun_struct *tun = tun_get(tfile);
2524 struct tun_msg_ctl *ctl = m->msg_control;
2525 struct xdp_buff *xdp;
2526
2527 if (!tun)
2528 return -EBADFD;
2529
2530 if (ctl && (ctl->type == TUN_MSG_PTR)) {
2531 struct tun_page tpage;
2532 int n = ctl->num;
2533 int flush = 0;
2534
2535 memset(&tpage, 0, sizeof(tpage));
2536
2537 local_bh_disable();
2538 rcu_read_lock();
2539
2540 for (i = 0; i < n; i++) {
2541 xdp = &((struct xdp_buff *)ctl->ptr)[i];
2542 tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2543 }
2544
2545 if (flush)
2546 xdp_do_flush_map();
2547
2548 rcu_read_unlock();
2549 local_bh_enable();
2550
2551 tun_put_page(&tpage);
2552
2553 ret = total_len;
2554 goto out;
2555 }
2556
2557 ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2558 m->msg_flags & MSG_DONTWAIT,
2559 m->msg_flags & MSG_MORE);
2560out:
2561 tun_put(tun);
2562 return ret;
2563}
2564
2565static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2566 int flags)
2567{
2568 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2569 struct tun_struct *tun = tun_get(tfile);
2570 void *ptr = m->msg_control;
2571 int ret;
2572
2573 if (!tun) {
2574 ret = -EBADFD;
2575 goto out_free;
2576 }
2577
2578 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2579 ret = -EINVAL;
2580 goto out_put_tun;
2581 }
2582 if (flags & MSG_ERRQUEUE) {
2583 ret = sock_recv_errqueue(sock->sk, m, total_len,
2584 SOL_PACKET, TUN_TX_TIMESTAMP);
2585 goto out;
2586 }
2587 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2588 if (ret > (ssize_t)total_len) {
2589 m->msg_flags |= MSG_TRUNC;
2590 ret = flags & MSG_TRUNC ? ret : total_len;
2591 }
2592out:
2593 tun_put(tun);
2594 return ret;
2595
2596out_put_tun:
2597 tun_put(tun);
2598out_free:
2599 tun_ptr_free(ptr);
2600 return ret;
2601}
2602
2603static int tun_ptr_peek_len(void *ptr)
2604{
2605 if (likely(ptr)) {
2606 if (tun_is_xdp_frame(ptr)) {
2607 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2608
2609 return xdpf->len;
2610 }
2611 return __skb_array_len_with_tag(ptr);
2612 } else {
2613 return 0;
2614 }
2615}
2616
2617static int tun_peek_len(struct socket *sock)
2618{
2619 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2620 struct tun_struct *tun;
2621 int ret = 0;
2622
2623 tun = tun_get(tfile);
2624 if (!tun)
2625 return 0;
2626
2627 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2628 tun_put(tun);
2629
2630 return ret;
2631}
2632
2633/* Ops structure to mimic raw sockets with tun */
2634static const struct proto_ops tun_socket_ops = {
2635 .peek_len = tun_peek_len,
2636 .sendmsg = tun_sendmsg,
2637 .recvmsg = tun_recvmsg,
2638};
2639
2640static struct proto tun_proto = {
2641 .name = "tun",
2642 .owner = THIS_MODULE,
2643 .obj_size = sizeof(struct tun_file),
2644};
2645
2646static int tun_flags(struct tun_struct *tun)
2647{
2648 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2649}
2650
2651static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2652 char *buf)
2653{
2654 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2655 return sprintf(buf, "0x%x\n", tun_flags(tun));
2656}
2657
2658static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2659 char *buf)
2660{
2661 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2662 return uid_valid(tun->owner)?
2663 sprintf(buf, "%u\n",
2664 from_kuid_munged(current_user_ns(), tun->owner)):
2665 sprintf(buf, "-1\n");
2666}
2667
2668static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2669 char *buf)
2670{
2671 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2672 return gid_valid(tun->group) ?
2673 sprintf(buf, "%u\n",
2674 from_kgid_munged(current_user_ns(), tun->group)):
2675 sprintf(buf, "-1\n");
2676}
2677
2678static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2679static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2680static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2681
2682static struct attribute *tun_dev_attrs[] = {
2683 &dev_attr_tun_flags.attr,
2684 &dev_attr_owner.attr,
2685 &dev_attr_group.attr,
2686 NULL
2687};
2688
2689static const struct attribute_group tun_attr_group = {
2690 .attrs = tun_dev_attrs
2691};
2692
2693static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2694{
2695 struct tun_struct *tun;
2696 struct tun_file *tfile = file->private_data;
2697 struct net_device *dev;
2698 int err;
2699
2700 if (tfile->detached)
2701 return -EINVAL;
2702
2703 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2704 if (!capable(CAP_NET_ADMIN))
2705 return -EPERM;
2706
2707 if (!(ifr->ifr_flags & IFF_NAPI) ||
2708 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2709 return -EINVAL;
2710 }
2711
2712 dev = __dev_get_by_name(net, ifr->ifr_name);
2713 if (dev) {
2714 if (ifr->ifr_flags & IFF_TUN_EXCL)
2715 return -EBUSY;
2716 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2717 tun = netdev_priv(dev);
2718 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2719 tun = netdev_priv(dev);
2720 else
2721 return -EINVAL;
2722
2723 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2724 !!(tun->flags & IFF_MULTI_QUEUE))
2725 return -EINVAL;
2726
2727 if (tun_not_capable(tun))
2728 return -EPERM;
2729 err = security_tun_dev_open(tun->security);
2730 if (err < 0)
2731 return err;
2732
2733 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2734 ifr->ifr_flags & IFF_NAPI,
2735 ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2736 if (err < 0)
2737 return err;
2738
2739 if (tun->flags & IFF_MULTI_QUEUE &&
2740 (tun->numqueues + tun->numdisabled > 1)) {
2741 /* One or more queue has already been attached, no need
2742 * to initialize the device again.
2743 */
2744 netdev_state_change(dev);
2745 return 0;
2746 }
2747
2748 tun->flags = (tun->flags & ~TUN_FEATURES) |
2749 (ifr->ifr_flags & TUN_FEATURES);
2750
2751 netdev_state_change(dev);
2752 } else {
2753 char *name;
2754 unsigned long flags = 0;
2755 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2756 MAX_TAP_QUEUES : 1;
2757
2758 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2759 return -EPERM;
2760 err = security_tun_dev_create();
2761 if (err < 0)
2762 return err;
2763
2764 /* Set dev type */
2765 if (ifr->ifr_flags & IFF_TUN) {
2766 /* TUN device */
2767 flags |= IFF_TUN;
2768 name = "tun%d";
2769 } else if (ifr->ifr_flags & IFF_TAP) {
2770 /* TAP device */
2771 flags |= IFF_TAP;
2772 name = "tap%d";
2773 } else
2774 return -EINVAL;
2775
2776 if (*ifr->ifr_name)
2777 name = ifr->ifr_name;
2778
2779 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2780 NET_NAME_UNKNOWN, tun_setup, queues,
2781 queues);
2782
2783 if (!dev)
2784 return -ENOMEM;
2785 err = dev_get_valid_name(net, dev, name);
2786 if (err < 0)
2787 goto err_free_dev;
2788
2789 dev_net_set(dev, net);
2790 dev->rtnl_link_ops = &tun_link_ops;
2791 dev->ifindex = tfile->ifindex;
2792 dev->sysfs_groups[0] = &tun_attr_group;
2793
2794 tun = netdev_priv(dev);
2795 tun->dev = dev;
2796 tun->flags = flags;
2797 tun->txflt.count = 0;
2798 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2799
2800 tun->align = NET_SKB_PAD;
2801 tun->filter_attached = false;
2802 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2803 tun->rx_batched = 0;
2804 RCU_INIT_POINTER(tun->steering_prog, NULL);
2805
2806 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2807 if (!tun->pcpu_stats) {
2808 err = -ENOMEM;
2809 goto err_free_dev;
2810 }
2811
2812 spin_lock_init(&tun->lock);
2813
2814 err = security_tun_dev_alloc_security(&tun->security);
2815 if (err < 0)
2816 goto err_free_stat;
2817
2818 tun_net_init(dev);
2819 tun_flow_init(tun);
2820
2821 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2822 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2823 NETIF_F_HW_VLAN_STAG_TX;
2824 dev->features = dev->hw_features | NETIF_F_LLTX;
2825 dev->vlan_features = dev->features &
2826 ~(NETIF_F_HW_VLAN_CTAG_TX |
2827 NETIF_F_HW_VLAN_STAG_TX);
2828
2829 tun->flags = (tun->flags & ~TUN_FEATURES) |
2830 (ifr->ifr_flags & TUN_FEATURES);
2831
2832 INIT_LIST_HEAD(&tun->disabled);
2833 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI,
2834 ifr->ifr_flags & IFF_NAPI_FRAGS, false);
2835 if (err < 0)
2836 goto err_free_flow;
2837
2838 err = register_netdevice(tun->dev);
2839 if (err < 0)
2840 goto err_detach;
2841 /* free_netdev() won't check refcnt, to aovid race
2842 * with dev_put() we need publish tun after registration.
2843 */
2844 rcu_assign_pointer(tfile->tun, tun);
2845 }
2846
2847 netif_carrier_on(tun->dev);
2848
2849 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2850
2851 /* Make sure persistent devices do not get stuck in
2852 * xoff state.
2853 */
2854 if (netif_running(tun->dev))
2855 netif_tx_wake_all_queues(tun->dev);
2856
2857 strcpy(ifr->ifr_name, tun->dev->name);
2858 return 0;
2859
2860err_detach:
2861 tun_detach_all(dev);
2862 /* register_netdevice() already called tun_free_netdev() */
2863 goto err_free_dev;
2864
2865err_free_flow:
2866 tun_flow_uninit(tun);
2867 security_tun_dev_free_security(tun->security);
2868err_free_stat:
2869 free_percpu(tun->pcpu_stats);
2870err_free_dev:
2871 free_netdev(dev);
2872 return err;
2873}
2874
2875static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2876{
2877 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2878
2879 strcpy(ifr->ifr_name, tun->dev->name);
2880
2881 ifr->ifr_flags = tun_flags(tun);
2882
2883}
2884
2885/* This is like a cut-down ethtool ops, except done via tun fd so no
2886 * privs required. */
2887static int set_offload(struct tun_struct *tun, unsigned long arg)
2888{
2889 netdev_features_t features = 0;
2890
2891 if (arg & TUN_F_CSUM) {
2892 features |= NETIF_F_HW_CSUM;
2893 arg &= ~TUN_F_CSUM;
2894
2895 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2896 if (arg & TUN_F_TSO_ECN) {
2897 features |= NETIF_F_TSO_ECN;
2898 arg &= ~TUN_F_TSO_ECN;
2899 }
2900 if (arg & TUN_F_TSO4)
2901 features |= NETIF_F_TSO;
2902 if (arg & TUN_F_TSO6)
2903 features |= NETIF_F_TSO6;
2904 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2905 }
2906
2907 arg &= ~TUN_F_UFO;
2908 }
2909
2910 /* This gives the user a way to test for new features in future by
2911 * trying to set them. */
2912 if (arg)
2913 return -EINVAL;
2914
2915 tun->set_features = features;
2916 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2917 tun->dev->wanted_features |= features;
2918 netdev_update_features(tun->dev);
2919
2920 return 0;
2921}
2922
2923static void tun_detach_filter(struct tun_struct *tun, int n)
2924{
2925 int i;
2926 struct tun_file *tfile;
2927
2928 for (i = 0; i < n; i++) {
2929 tfile = rtnl_dereference(tun->tfiles[i]);
2930 lock_sock(tfile->socket.sk);
2931 sk_detach_filter(tfile->socket.sk);
2932 release_sock(tfile->socket.sk);
2933 }
2934
2935 tun->filter_attached = false;
2936}
2937
2938static int tun_attach_filter(struct tun_struct *tun)
2939{
2940 int i, ret = 0;
2941 struct tun_file *tfile;
2942
2943 for (i = 0; i < tun->numqueues; i++) {
2944 tfile = rtnl_dereference(tun->tfiles[i]);
2945 lock_sock(tfile->socket.sk);
2946 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2947 release_sock(tfile->socket.sk);
2948 if (ret) {
2949 tun_detach_filter(tun, i);
2950 return ret;
2951 }
2952 }
2953
2954 tun->filter_attached = true;
2955 return ret;
2956}
2957
2958static void tun_set_sndbuf(struct tun_struct *tun)
2959{
2960 struct tun_file *tfile;
2961 int i;
2962
2963 for (i = 0; i < tun->numqueues; i++) {
2964 tfile = rtnl_dereference(tun->tfiles[i]);
2965 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2966 }
2967}
2968
2969static int tun_set_queue(struct file *file, struct ifreq *ifr)
2970{
2971 struct tun_file *tfile = file->private_data;
2972 struct tun_struct *tun;
2973 int ret = 0;
2974
2975 rtnl_lock();
2976
2977 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2978 tun = tfile->detached;
2979 if (!tun) {
2980 ret = -EINVAL;
2981 goto unlock;
2982 }
2983 ret = security_tun_dev_attach_queue(tun->security);
2984 if (ret < 0)
2985 goto unlock;
2986 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2987 tun->flags & IFF_NAPI_FRAGS, true);
2988 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2989 tun = rtnl_dereference(tfile->tun);
2990 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2991 ret = -EINVAL;
2992 else
2993 __tun_detach(tfile, false);
2994 } else
2995 ret = -EINVAL;
2996
2997 if (ret >= 0)
2998 netdev_state_change(tun->dev);
2999
3000unlock:
3001 rtnl_unlock();
3002 return ret;
3003}
3004
3005static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
3006 void __user *data)
3007{
3008 struct bpf_prog *prog;
3009 int fd;
3010
3011 if (copy_from_user(&fd, data, sizeof(fd)))
3012 return -EFAULT;
3013
3014 if (fd == -1) {
3015 prog = NULL;
3016 } else {
3017 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
3018 if (IS_ERR(prog))
3019 return PTR_ERR(prog);
3020 }
3021
3022 return __tun_set_ebpf(tun, prog_p, prog);
3023}
3024
3025static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
3026 unsigned long arg, int ifreq_len)
3027{
3028 struct tun_file *tfile = file->private_data;
3029 struct net *net = sock_net(&tfile->sk);
3030 struct tun_struct *tun;
3031 void __user* argp = (void __user*)arg;
3032 unsigned int ifindex, carrier;
3033 struct ifreq ifr;
3034 kuid_t owner;
3035 kgid_t group;
3036 int sndbuf;
3037 int vnet_hdr_sz;
3038 int le;
3039 int ret;
3040 bool do_notify = false;
3041
3042 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3043 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3044 if (copy_from_user(&ifr, argp, ifreq_len))
3045 return -EFAULT;
3046 } else {
3047 memset(&ifr, 0, sizeof(ifr));
3048 }
3049 if (cmd == TUNGETFEATURES) {
3050 /* Currently this just means: "what IFF flags are valid?".
3051 * This is needed because we never checked for invalid flags on
3052 * TUNSETIFF.
3053 */
3054 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
3055 (unsigned int __user*)argp);
3056 } else if (cmd == TUNSETQUEUE) {
3057 return tun_set_queue(file, &ifr);
3058 } else if (cmd == SIOCGSKNS) {
3059 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3060 return -EPERM;
3061 return open_related_ns(&net->ns, get_net_ns);
3062 }
3063
3064 ret = 0;
3065 rtnl_lock();
3066
3067 tun = tun_get(tfile);
3068 if (cmd == TUNSETIFF) {
3069 ret = -EEXIST;
3070 if (tun)
3071 goto unlock;
3072
3073 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3074
3075 ret = tun_set_iff(net, file, &ifr);
3076
3077 if (ret)
3078 goto unlock;
3079
3080 if (copy_to_user(argp, &ifr, ifreq_len))
3081 ret = -EFAULT;
3082 goto unlock;
3083 }
3084 if (cmd == TUNSETIFINDEX) {
3085 ret = -EPERM;
3086 if (tun)
3087 goto unlock;
3088
3089 ret = -EFAULT;
3090 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3091 goto unlock;
3092
3093 ret = 0;
3094 tfile->ifindex = ifindex;
3095 goto unlock;
3096 }
3097
3098 ret = -EBADFD;
3099 if (!tun)
3100 goto unlock;
3101
3102 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
3103
3104 net = dev_net(tun->dev);
3105 ret = 0;
3106 switch (cmd) {
3107 case TUNGETIFF:
3108 tun_get_iff(tun, &ifr);
3109
3110 if (tfile->detached)
3111 ifr.ifr_flags |= IFF_DETACH_QUEUE;
3112 if (!tfile->socket.sk->sk_filter)
3113 ifr.ifr_flags |= IFF_NOFILTER;
3114
3115 if (copy_to_user(argp, &ifr, ifreq_len))
3116 ret = -EFAULT;
3117 break;
3118
3119 case TUNSETNOCSUM:
3120 /* Disable/Enable checksum */
3121
3122 /* [unimplemented] */
3123 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
3124 arg ? "disabled" : "enabled");
3125 break;
3126
3127 case TUNSETPERSIST:
3128 /* Disable/Enable persist mode. Keep an extra reference to the
3129 * module to prevent the module being unprobed.
3130 */
3131 if (arg && !(tun->flags & IFF_PERSIST)) {
3132 tun->flags |= IFF_PERSIST;
3133 __module_get(THIS_MODULE);
3134 do_notify = true;
3135 }
3136 if (!arg && (tun->flags & IFF_PERSIST)) {
3137 tun->flags &= ~IFF_PERSIST;
3138 module_put(THIS_MODULE);
3139 do_notify = true;
3140 }
3141
3142 tun_debug(KERN_INFO, tun, "persist %s\n",
3143 arg ? "enabled" : "disabled");
3144 break;
3145
3146 case TUNSETOWNER:
3147 /* Set owner of the device */
3148 owner = make_kuid(current_user_ns(), arg);
3149 if (!uid_valid(owner)) {
3150 ret = -EINVAL;
3151 break;
3152 }
3153 tun->owner = owner;
3154 do_notify = true;
3155 tun_debug(KERN_INFO, tun, "owner set to %u\n",
3156 from_kuid(&init_user_ns, tun->owner));
3157 break;
3158
3159 case TUNSETGROUP:
3160 /* Set group of the device */
3161 group = make_kgid(current_user_ns(), arg);
3162 if (!gid_valid(group)) {
3163 ret = -EINVAL;
3164 break;
3165 }
3166 tun->group = group;
3167 do_notify = true;
3168 tun_debug(KERN_INFO, tun, "group set to %u\n",
3169 from_kgid(&init_user_ns, tun->group));
3170 break;
3171
3172 case TUNSETLINK:
3173 /* Only allow setting the type when the interface is down */
3174 if (tun->dev->flags & IFF_UP) {
3175 tun_debug(KERN_INFO, tun,
3176 "Linktype set failed because interface is up\n");
3177 ret = -EBUSY;
3178 } else {
3179 tun->dev->type = (int) arg;
3180 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
3181 tun->dev->type);
3182 ret = 0;
3183 }
3184 break;
3185
3186#ifdef TUN_DEBUG
3187 case TUNSETDEBUG:
3188 tun->debug = arg;
3189 break;
3190#endif
3191 case TUNSETOFFLOAD:
3192 ret = set_offload(tun, arg);
3193 break;
3194
3195 case TUNSETTXFILTER:
3196 /* Can be set only for TAPs */
3197 ret = -EINVAL;
3198 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3199 break;
3200 ret = update_filter(&tun->txflt, (void __user *)arg);
3201 break;
3202
3203 case SIOCGIFHWADDR:
3204 /* Get hw address */
3205 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3206 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3207 if (copy_to_user(argp, &ifr, ifreq_len))
3208 ret = -EFAULT;
3209 break;
3210
3211 case SIOCSIFHWADDR:
3212 /* Set hw address */
3213 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
3214 ifr.ifr_hwaddr.sa_data);
3215
3216 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr, NULL);
3217 break;
3218
3219 case TUNGETSNDBUF:
3220 sndbuf = tfile->socket.sk->sk_sndbuf;
3221 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3222 ret = -EFAULT;
3223 break;
3224
3225 case TUNSETSNDBUF:
3226 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3227 ret = -EFAULT;
3228 break;
3229 }
3230 if (sndbuf <= 0) {
3231 ret = -EINVAL;
3232 break;
3233 }
3234
3235 tun->sndbuf = sndbuf;
3236 tun_set_sndbuf(tun);
3237 break;
3238
3239 case TUNGETVNETHDRSZ:
3240 vnet_hdr_sz = tun->vnet_hdr_sz;
3241 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3242 ret = -EFAULT;
3243 break;
3244
3245 case TUNSETVNETHDRSZ:
3246 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3247 ret = -EFAULT;
3248 break;
3249 }
3250 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3251 ret = -EINVAL;
3252 break;
3253 }
3254
3255 tun->vnet_hdr_sz = vnet_hdr_sz;
3256 break;
3257
3258 case TUNGETVNETLE:
3259 le = !!(tun->flags & TUN_VNET_LE);
3260 if (put_user(le, (int __user *)argp))
3261 ret = -EFAULT;
3262 break;
3263
3264 case TUNSETVNETLE:
3265 if (get_user(le, (int __user *)argp)) {
3266 ret = -EFAULT;
3267 break;
3268 }
3269 if (le)
3270 tun->flags |= TUN_VNET_LE;
3271 else
3272 tun->flags &= ~TUN_VNET_LE;
3273 break;
3274
3275 case TUNGETVNETBE:
3276 ret = tun_get_vnet_be(tun, argp);
3277 break;
3278
3279 case TUNSETVNETBE:
3280 ret = tun_set_vnet_be(tun, argp);
3281 break;
3282
3283 case TUNATTACHFILTER:
3284 /* Can be set only for TAPs */
3285 ret = -EINVAL;
3286 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3287 break;
3288 ret = -EFAULT;
3289 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3290 break;
3291
3292 ret = tun_attach_filter(tun);
3293 break;
3294
3295 case TUNDETACHFILTER:
3296 /* Can be set only for TAPs */
3297 ret = -EINVAL;
3298 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3299 break;
3300 ret = 0;
3301 tun_detach_filter(tun, tun->numqueues);
3302 break;
3303
3304 case TUNGETFILTER:
3305 ret = -EINVAL;
3306 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3307 break;
3308 ret = -EFAULT;
3309 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3310 break;
3311 ret = 0;
3312 break;
3313
3314 case TUNSETSTEERINGEBPF:
3315 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3316 break;
3317
3318 case TUNSETFILTEREBPF:
3319 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3320 break;
3321
3322 case TUNSETCARRIER:
3323 ret = -EFAULT;
3324 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3325 goto unlock;
3326
3327 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3328 break;
3329
3330 case TUNGETDEVNETNS:
3331 ret = -EPERM;
3332 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3333 goto unlock;
3334 ret = open_related_ns(&net->ns, get_net_ns);
3335 break;
3336
3337 default:
3338 ret = -EINVAL;
3339 break;
3340 }
3341
3342 if (do_notify)
3343 netdev_state_change(tun->dev);
3344
3345unlock:
3346 rtnl_unlock();
3347 if (tun)
3348 tun_put(tun);
3349 return ret;
3350}
3351
3352static long tun_chr_ioctl(struct file *file,
3353 unsigned int cmd, unsigned long arg)
3354{
3355 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3356}
3357
3358#ifdef CONFIG_COMPAT
3359static long tun_chr_compat_ioctl(struct file *file,
3360 unsigned int cmd, unsigned long arg)
3361{
3362 switch (cmd) {
3363 case TUNSETIFF:
3364 case TUNGETIFF:
3365 case TUNSETTXFILTER:
3366 case TUNGETSNDBUF:
3367 case TUNSETSNDBUF:
3368 case SIOCGIFHWADDR:
3369 case SIOCSIFHWADDR:
3370 arg = (unsigned long)compat_ptr(arg);
3371 break;
3372 default:
3373 arg = (compat_ulong_t)arg;
3374 break;
3375 }
3376
3377 /*
3378 * compat_ifreq is shorter than ifreq, so we must not access beyond
3379 * the end of that structure. All fields that are used in this
3380 * driver are compatible though, we don't need to convert the
3381 * contents.
3382 */
3383 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3384}
3385#endif /* CONFIG_COMPAT */
3386
3387static int tun_chr_fasync(int fd, struct file *file, int on)
3388{
3389 struct tun_file *tfile = file->private_data;
3390 int ret;
3391
3392 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3393 goto out;
3394
3395 if (on) {
3396 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3397 tfile->flags |= TUN_FASYNC;
3398 } else
3399 tfile->flags &= ~TUN_FASYNC;
3400 ret = 0;
3401out:
3402 return ret;
3403}
3404
3405static int tun_chr_open(struct inode *inode, struct file * file)
3406{
3407 struct net *net = current->nsproxy->net_ns;
3408 struct tun_file *tfile;
3409
3410 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
3411
3412 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3413 &tun_proto, 0);
3414 if (!tfile)
3415 return -ENOMEM;
3416 if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3417 sk_free(&tfile->sk);
3418 return -ENOMEM;
3419 }
3420
3421 mutex_init(&tfile->napi_mutex);
3422 RCU_INIT_POINTER(tfile->tun, NULL);
3423 tfile->flags = 0;
3424 tfile->ifindex = 0;
3425
3426 init_waitqueue_head(&tfile->socket.wq.wait);
3427
3428 tfile->socket.file = file;
3429 tfile->socket.ops = &tun_socket_ops;
3430
3431 sock_init_data(&tfile->socket, &tfile->sk);
3432
3433 tfile->sk.sk_write_space = tun_sock_write_space;
3434 tfile->sk.sk_sndbuf = INT_MAX;
3435
3436 file->private_data = tfile;
3437 INIT_LIST_HEAD(&tfile->next);
3438
3439 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3440
3441 return 0;
3442}
3443
3444static int tun_chr_close(struct inode *inode, struct file *file)
3445{
3446 struct tun_file *tfile = file->private_data;
3447
3448 tun_detach(tfile, true);
3449
3450 return 0;
3451}
3452
3453#ifdef CONFIG_PROC_FS
3454static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3455{
3456 struct tun_file *tfile = file->private_data;
3457 struct tun_struct *tun;
3458 struct ifreq ifr;
3459
3460 memset(&ifr, 0, sizeof(ifr));
3461
3462 rtnl_lock();
3463 tun = tun_get(tfile);
3464 if (tun)
3465 tun_get_iff(tun, &ifr);
3466 rtnl_unlock();
3467
3468 if (tun)
3469 tun_put(tun);
3470
3471 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3472}
3473#endif
3474
3475static const struct file_operations tun_fops = {
3476 .owner = THIS_MODULE,
3477 .llseek = no_llseek,
3478 .read_iter = tun_chr_read_iter,
3479 .write_iter = tun_chr_write_iter,
3480 .poll = tun_chr_poll,
3481 .unlocked_ioctl = tun_chr_ioctl,
3482#ifdef CONFIG_COMPAT
3483 .compat_ioctl = tun_chr_compat_ioctl,
3484#endif
3485 .open = tun_chr_open,
3486 .release = tun_chr_close,
3487 .fasync = tun_chr_fasync,
3488#ifdef CONFIG_PROC_FS
3489 .show_fdinfo = tun_chr_show_fdinfo,
3490#endif
3491};
3492
3493static struct miscdevice tun_miscdev = {
3494 .minor = TUN_MINOR,
3495 .name = "tun",
3496 .nodename = "net/tun",
3497 .fops = &tun_fops,
3498};
3499
3500/* ethtool interface */
3501
3502static void tun_default_link_ksettings(struct net_device *dev,
3503 struct ethtool_link_ksettings *cmd)
3504{
3505 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3506 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3507 cmd->base.speed = SPEED_10;
3508 cmd->base.duplex = DUPLEX_FULL;
3509 cmd->base.port = PORT_TP;
3510 cmd->base.phy_address = 0;
3511 cmd->base.autoneg = AUTONEG_DISABLE;
3512}
3513
3514static int tun_get_link_ksettings(struct net_device *dev,
3515 struct ethtool_link_ksettings *cmd)
3516{
3517 struct tun_struct *tun = netdev_priv(dev);
3518
3519 memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3520 return 0;
3521}
3522
3523static int tun_set_link_ksettings(struct net_device *dev,
3524 const struct ethtool_link_ksettings *cmd)
3525{
3526 struct tun_struct *tun = netdev_priv(dev);
3527
3528 memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3529 return 0;
3530}
3531
3532static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3533{
3534 struct tun_struct *tun = netdev_priv(dev);
3535
3536 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3537 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3538
3539 switch (tun->flags & TUN_TYPE_MASK) {
3540 case IFF_TUN:
3541 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3542 break;
3543 case IFF_TAP:
3544 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3545 break;
3546 }
3547}
3548
3549static u32 tun_get_msglevel(struct net_device *dev)
3550{
3551#ifdef TUN_DEBUG
3552 struct tun_struct *tun = netdev_priv(dev);
3553 return tun->debug;
3554#else
3555 return -EOPNOTSUPP;
3556#endif
3557}
3558
3559static void tun_set_msglevel(struct net_device *dev, u32 value)
3560{
3561#ifdef TUN_DEBUG
3562 struct tun_struct *tun = netdev_priv(dev);
3563 tun->debug = value;
3564#endif
3565}
3566
3567static int tun_get_coalesce(struct net_device *dev,
3568 struct ethtool_coalesce *ec)
3569{
3570 struct tun_struct *tun = netdev_priv(dev);
3571
3572 ec->rx_max_coalesced_frames = tun->rx_batched;
3573
3574 return 0;
3575}
3576
3577static int tun_set_coalesce(struct net_device *dev,
3578 struct ethtool_coalesce *ec)
3579{
3580 struct tun_struct *tun = netdev_priv(dev);
3581
3582 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3583 tun->rx_batched = NAPI_POLL_WEIGHT;
3584 else
3585 tun->rx_batched = ec->rx_max_coalesced_frames;
3586
3587 return 0;
3588}
3589
3590static const struct ethtool_ops tun_ethtool_ops = {
3591 .get_drvinfo = tun_get_drvinfo,
3592 .get_msglevel = tun_get_msglevel,
3593 .set_msglevel = tun_set_msglevel,
3594 .get_link = ethtool_op_get_link,
3595 .get_ts_info = ethtool_op_get_ts_info,
3596 .get_coalesce = tun_get_coalesce,
3597 .set_coalesce = tun_set_coalesce,
3598 .get_link_ksettings = tun_get_link_ksettings,
3599 .set_link_ksettings = tun_set_link_ksettings,
3600};
3601
3602static int tun_queue_resize(struct tun_struct *tun)
3603{
3604 struct net_device *dev = tun->dev;
3605 struct tun_file *tfile;
3606 struct ptr_ring **rings;
3607 int n = tun->numqueues + tun->numdisabled;
3608 int ret, i;
3609
3610 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3611 if (!rings)
3612 return -ENOMEM;
3613
3614 for (i = 0; i < tun->numqueues; i++) {
3615 tfile = rtnl_dereference(tun->tfiles[i]);
3616 rings[i] = &tfile->tx_ring;
3617 }
3618 list_for_each_entry(tfile, &tun->disabled, next)
3619 rings[i++] = &tfile->tx_ring;
3620
3621 ret = ptr_ring_resize_multiple(rings, n,
3622 dev->tx_queue_len, GFP_KERNEL,
3623 tun_ptr_free);
3624
3625 kfree(rings);
3626 return ret;
3627}
3628
3629static int tun_device_event(struct notifier_block *unused,
3630 unsigned long event, void *ptr)
3631{
3632 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3633 struct tun_struct *tun = netdev_priv(dev);
3634 int i;
3635
3636 if (dev->rtnl_link_ops != &tun_link_ops)
3637 return NOTIFY_DONE;
3638
3639 switch (event) {
3640 case NETDEV_CHANGE_TX_QUEUE_LEN:
3641 if (tun_queue_resize(tun))
3642 return NOTIFY_BAD;
3643 break;
3644 case NETDEV_UP:
3645 for (i = 0; i < tun->numqueues; i++) {
3646 struct tun_file *tfile;
3647
3648 tfile = rtnl_dereference(tun->tfiles[i]);
3649 tfile->socket.sk->sk_write_space(tfile->socket.sk);
3650 }
3651 break;
3652 default:
3653 break;
3654 }
3655
3656 return NOTIFY_DONE;
3657}
3658
3659static struct notifier_block tun_notifier_block __read_mostly = {
3660 .notifier_call = tun_device_event,
3661};
3662
3663static int __init tun_init(void)
3664{
3665 int ret = 0;
3666
3667 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3668
3669 ret = rtnl_link_register(&tun_link_ops);
3670 if (ret) {
3671 pr_err("Can't register link_ops\n");
3672 goto err_linkops;
3673 }
3674
3675 ret = misc_register(&tun_miscdev);
3676 if (ret) {
3677 pr_err("Can't register misc device %d\n", TUN_MINOR);
3678 goto err_misc;
3679 }
3680
3681 ret = register_netdevice_notifier(&tun_notifier_block);
3682 if (ret) {
3683 pr_err("Can't register netdevice notifier\n");
3684 goto err_notifier;
3685 }
3686
3687 return 0;
3688
3689err_notifier:
3690 misc_deregister(&tun_miscdev);
3691err_misc:
3692 rtnl_link_unregister(&tun_link_ops);
3693err_linkops:
3694 return ret;
3695}
3696
3697static void tun_cleanup(void)
3698{
3699 misc_deregister(&tun_miscdev);
3700 rtnl_link_unregister(&tun_link_ops);
3701 unregister_netdevice_notifier(&tun_notifier_block);
3702}
3703
3704/* Get an underlying socket object from tun file. Returns error unless file is
3705 * attached to a device. The returned object works like a packet socket, it
3706 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3707 * holding a reference to the file for as long as the socket is in use. */
3708struct socket *tun_get_socket(struct file *file)
3709{
3710 struct tun_file *tfile;
3711 if (file->f_op != &tun_fops)
3712 return ERR_PTR(-EINVAL);
3713 tfile = file->private_data;
3714 if (!tfile)
3715 return ERR_PTR(-EBADFD);
3716 return &tfile->socket;
3717}
3718EXPORT_SYMBOL_GPL(tun_get_socket);
3719
3720struct ptr_ring *tun_get_tx_ring(struct file *file)
3721{
3722 struct tun_file *tfile;
3723
3724 if (file->f_op != &tun_fops)
3725 return ERR_PTR(-EINVAL);
3726 tfile = file->private_data;
3727 if (!tfile)
3728 return ERR_PTR(-EBADFD);
3729 return &tfile->tx_ring;
3730}
3731EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3732
3733module_init(tun_init);
3734module_exit(tun_cleanup);
3735MODULE_DESCRIPTION(DRV_DESCRIPTION);
3736MODULE_AUTHOR(DRV_COPYRIGHT);
3737MODULE_LICENSE("GPL");
3738MODULE_ALIAS_MISCDEV(TUN_MINOR);
3739MODULE_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
73#include <linux/uaccess.h>
74#include <linux/proc_fs.h>
75
76static void tun_default_link_ksettings(struct net_device *dev,
77 struct ethtool_link_ksettings *cmd);
78
79#define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
80
81/* TUN device flags */
82
83/* IFF_ATTACH_QUEUE is never stored in device flags,
84 * overload it to mean fasync when stored there.
85 */
86#define TUN_FASYNC IFF_ATTACH_QUEUE
87/* High bits in flags field are unused. */
88#define TUN_VNET_LE 0x80000000
89#define TUN_VNET_BE 0x40000000
90
91#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
92 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
93
94#define GOODCOPY_LEN 128
95
96#define FLT_EXACT_COUNT 8
97struct tap_filter {
98 unsigned int count; /* Number of addrs. Zero means disabled */
99 u32 mask[2]; /* Mask of the hashed addrs */
100 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
101};
102
103/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
104 * to max number of VCPUs in guest. */
105#define MAX_TAP_QUEUES 256
106#define MAX_TAP_FLOWS 4096
107
108#define TUN_FLOW_EXPIRE (3 * HZ)
109
110struct tun_pcpu_stats {
111 u64_stats_t rx_packets;
112 u64_stats_t rx_bytes;
113 u64_stats_t tx_packets;
114 u64_stats_t tx_bytes;
115 struct u64_stats_sync syncp;
116 u32 rx_dropped;
117 u32 tx_dropped;
118 u32 rx_frame_errors;
119};
120
121/* A tun_file connects an open character device to a tuntap netdevice. It
122 * also contains all socket related structures (except sock_fprog and tap_filter)
123 * to serve as one transmit queue for tuntap device. The sock_fprog and
124 * tap_filter were kept in tun_struct since they were used for filtering for the
125 * netdevice not for a specific queue (at least I didn't see the requirement for
126 * this).
127 *
128 * RCU usage:
129 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
130 * other can only be read while rcu_read_lock or rtnl_lock is held.
131 */
132struct tun_file {
133 struct sock sk;
134 struct socket socket;
135 struct tun_struct __rcu *tun;
136 struct fasync_struct *fasync;
137 /* only used for fasnyc */
138 unsigned int flags;
139 union {
140 u16 queue_index;
141 unsigned int ifindex;
142 };
143 struct napi_struct napi;
144 bool napi_enabled;
145 bool napi_frags_enabled;
146 struct mutex napi_mutex; /* Protects access to the above napi */
147 struct list_head next;
148 struct tun_struct *detached;
149 struct ptr_ring tx_ring;
150 struct xdp_rxq_info xdp_rxq;
151};
152
153struct tun_page {
154 struct page *page;
155 int count;
156};
157
158struct tun_flow_entry {
159 struct hlist_node hash_link;
160 struct rcu_head rcu;
161 struct tun_struct *tun;
162
163 u32 rxhash;
164 u32 rps_rxhash;
165 int queue_index;
166 unsigned long updated ____cacheline_aligned_in_smp;
167};
168
169#define TUN_NUM_FLOW_ENTRIES 1024
170#define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
171
172struct tun_prog {
173 struct rcu_head rcu;
174 struct bpf_prog *prog;
175};
176
177/* Since the socket were moved to tun_file, to preserve the behavior of persist
178 * device, socket filter, sndbuf and vnet header size were restore when the
179 * file were attached to a persist device.
180 */
181struct tun_struct {
182 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
183 unsigned int numqueues;
184 unsigned int flags;
185 kuid_t owner;
186 kgid_t group;
187
188 struct net_device *dev;
189 netdev_features_t set_features;
190#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
191 NETIF_F_TSO6)
192
193 int align;
194 int vnet_hdr_sz;
195 int sndbuf;
196 struct tap_filter txflt;
197 struct sock_fprog fprog;
198 /* protected by rtnl lock */
199 bool filter_attached;
200 u32 msg_enable;
201 spinlock_t lock;
202 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
203 struct timer_list flow_gc_timer;
204 unsigned long ageing_time;
205 unsigned int numdisabled;
206 struct list_head disabled;
207 void *security;
208 u32 flow_count;
209 u32 rx_batched;
210 struct tun_pcpu_stats __percpu *pcpu_stats;
211 struct bpf_prog __rcu *xdp_prog;
212 struct tun_prog __rcu *steering_prog;
213 struct tun_prog __rcu *filter_prog;
214 struct ethtool_link_ksettings link_ksettings;
215};
216
217struct veth {
218 __be16 h_vlan_proto;
219 __be16 h_vlan_TCI;
220};
221
222bool tun_is_xdp_frame(void *ptr)
223{
224 return (unsigned long)ptr & TUN_XDP_FLAG;
225}
226EXPORT_SYMBOL(tun_is_xdp_frame);
227
228void *tun_xdp_to_ptr(void *ptr)
229{
230 return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
231}
232EXPORT_SYMBOL(tun_xdp_to_ptr);
233
234void *tun_ptr_to_xdp(void *ptr)
235{
236 return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
237}
238EXPORT_SYMBOL(tun_ptr_to_xdp);
239
240static int tun_napi_receive(struct napi_struct *napi, int budget)
241{
242 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
243 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
244 struct sk_buff_head process_queue;
245 struct sk_buff *skb;
246 int received = 0;
247
248 __skb_queue_head_init(&process_queue);
249
250 spin_lock(&queue->lock);
251 skb_queue_splice_tail_init(queue, &process_queue);
252 spin_unlock(&queue->lock);
253
254 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
255 napi_gro_receive(napi, skb);
256 ++received;
257 }
258
259 if (!skb_queue_empty(&process_queue)) {
260 spin_lock(&queue->lock);
261 skb_queue_splice(&process_queue, queue);
262 spin_unlock(&queue->lock);
263 }
264
265 return received;
266}
267
268static int tun_napi_poll(struct napi_struct *napi, int budget)
269{
270 unsigned int received;
271
272 received = tun_napi_receive(napi, budget);
273
274 if (received < budget)
275 napi_complete_done(napi, received);
276
277 return received;
278}
279
280static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
281 bool napi_en, bool napi_frags)
282{
283 tfile->napi_enabled = napi_en;
284 tfile->napi_frags_enabled = napi_en && napi_frags;
285 if (napi_en) {
286 netif_tx_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
287 NAPI_POLL_WEIGHT);
288 napi_enable(&tfile->napi);
289 }
290}
291
292static void tun_napi_disable(struct tun_file *tfile)
293{
294 if (tfile->napi_enabled)
295 napi_disable(&tfile->napi);
296}
297
298static void tun_napi_del(struct tun_file *tfile)
299{
300 if (tfile->napi_enabled)
301 netif_napi_del(&tfile->napi);
302}
303
304static bool tun_napi_frags_enabled(const struct tun_file *tfile)
305{
306 return tfile->napi_frags_enabled;
307}
308
309#ifdef CONFIG_TUN_VNET_CROSS_LE
310static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
311{
312 return tun->flags & TUN_VNET_BE ? false :
313 virtio_legacy_is_little_endian();
314}
315
316static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
317{
318 int be = !!(tun->flags & TUN_VNET_BE);
319
320 if (put_user(be, argp))
321 return -EFAULT;
322
323 return 0;
324}
325
326static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
327{
328 int be;
329
330 if (get_user(be, argp))
331 return -EFAULT;
332
333 if (be)
334 tun->flags |= TUN_VNET_BE;
335 else
336 tun->flags &= ~TUN_VNET_BE;
337
338 return 0;
339}
340#else
341static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
342{
343 return virtio_legacy_is_little_endian();
344}
345
346static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
347{
348 return -EINVAL;
349}
350
351static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
352{
353 return -EINVAL;
354}
355#endif /* CONFIG_TUN_VNET_CROSS_LE */
356
357static inline bool tun_is_little_endian(struct tun_struct *tun)
358{
359 return tun->flags & TUN_VNET_LE ||
360 tun_legacy_is_little_endian(tun);
361}
362
363static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
364{
365 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
366}
367
368static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
369{
370 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
371}
372
373static inline u32 tun_hashfn(u32 rxhash)
374{
375 return rxhash & TUN_MASK_FLOW_ENTRIES;
376}
377
378static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
379{
380 struct tun_flow_entry *e;
381
382 hlist_for_each_entry_rcu(e, head, hash_link) {
383 if (e->rxhash == rxhash)
384 return e;
385 }
386 return NULL;
387}
388
389static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
390 struct hlist_head *head,
391 u32 rxhash, u16 queue_index)
392{
393 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
394
395 if (e) {
396 netif_info(tun, tx_queued, tun->dev,
397 "create flow: hash %u index %u\n",
398 rxhash, queue_index);
399 e->updated = jiffies;
400 e->rxhash = rxhash;
401 e->rps_rxhash = 0;
402 e->queue_index = queue_index;
403 e->tun = tun;
404 hlist_add_head_rcu(&e->hash_link, head);
405 ++tun->flow_count;
406 }
407 return e;
408}
409
410static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
411{
412 netif_info(tun, tx_queued, tun->dev, "delete flow: hash %u index %u\n",
413 e->rxhash, e->queue_index);
414 hlist_del_rcu(&e->hash_link);
415 kfree_rcu(e, rcu);
416 --tun->flow_count;
417}
418
419static void tun_flow_flush(struct tun_struct *tun)
420{
421 int i;
422
423 spin_lock_bh(&tun->lock);
424 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
425 struct tun_flow_entry *e;
426 struct hlist_node *n;
427
428 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
429 tun_flow_delete(tun, e);
430 }
431 spin_unlock_bh(&tun->lock);
432}
433
434static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
435{
436 int i;
437
438 spin_lock_bh(&tun->lock);
439 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
440 struct tun_flow_entry *e;
441 struct hlist_node *n;
442
443 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
444 if (e->queue_index == queue_index)
445 tun_flow_delete(tun, e);
446 }
447 }
448 spin_unlock_bh(&tun->lock);
449}
450
451static void tun_flow_cleanup(struct timer_list *t)
452{
453 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
454 unsigned long delay = tun->ageing_time;
455 unsigned long next_timer = jiffies + delay;
456 unsigned long count = 0;
457 int i;
458
459 spin_lock(&tun->lock);
460 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
461 struct tun_flow_entry *e;
462 struct hlist_node *n;
463
464 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
465 unsigned long this_timer;
466
467 this_timer = e->updated + delay;
468 if (time_before_eq(this_timer, jiffies)) {
469 tun_flow_delete(tun, e);
470 continue;
471 }
472 count++;
473 if (time_before(this_timer, next_timer))
474 next_timer = this_timer;
475 }
476 }
477
478 if (count)
479 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
480 spin_unlock(&tun->lock);
481}
482
483static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
484 struct tun_file *tfile)
485{
486 struct hlist_head *head;
487 struct tun_flow_entry *e;
488 unsigned long delay = tun->ageing_time;
489 u16 queue_index = tfile->queue_index;
490
491 head = &tun->flows[tun_hashfn(rxhash)];
492
493 rcu_read_lock();
494
495 e = tun_flow_find(head, rxhash);
496 if (likely(e)) {
497 /* TODO: keep queueing to old queue until it's empty? */
498 if (READ_ONCE(e->queue_index) != queue_index)
499 WRITE_ONCE(e->queue_index, queue_index);
500 if (e->updated != jiffies)
501 e->updated = jiffies;
502 sock_rps_record_flow_hash(e->rps_rxhash);
503 } else {
504 spin_lock_bh(&tun->lock);
505 if (!tun_flow_find(head, rxhash) &&
506 tun->flow_count < MAX_TAP_FLOWS)
507 tun_flow_create(tun, head, rxhash, queue_index);
508
509 if (!timer_pending(&tun->flow_gc_timer))
510 mod_timer(&tun->flow_gc_timer,
511 round_jiffies_up(jiffies + delay));
512 spin_unlock_bh(&tun->lock);
513 }
514
515 rcu_read_unlock();
516}
517
518/* Save the hash received in the stack receive path and update the
519 * flow_hash table accordingly.
520 */
521static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
522{
523 if (unlikely(e->rps_rxhash != hash))
524 e->rps_rxhash = hash;
525}
526
527/* We try to identify a flow through its rxhash. The reason that
528 * we do not check rxq no. is because some cards(e.g 82599), chooses
529 * the rxq based on the txq where the last packet of the flow comes. As
530 * the userspace application move between processors, we may get a
531 * different rxq no. here.
532 */
533static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
534{
535 struct tun_flow_entry *e;
536 u32 txq = 0;
537 u32 numqueues = 0;
538
539 numqueues = READ_ONCE(tun->numqueues);
540
541 txq = __skb_get_hash_symmetric(skb);
542 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
543 if (e) {
544 tun_flow_save_rps_rxhash(e, txq);
545 txq = e->queue_index;
546 } else {
547 /* use multiply and shift instead of expensive divide */
548 txq = ((u64)txq * numqueues) >> 32;
549 }
550
551 return txq;
552}
553
554static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
555{
556 struct tun_prog *prog;
557 u32 numqueues;
558 u16 ret = 0;
559
560 numqueues = READ_ONCE(tun->numqueues);
561 if (!numqueues)
562 return 0;
563
564 prog = rcu_dereference(tun->steering_prog);
565 if (prog)
566 ret = bpf_prog_run_clear_cb(prog->prog, skb);
567
568 return ret % numqueues;
569}
570
571static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
572 struct net_device *sb_dev)
573{
574 struct tun_struct *tun = netdev_priv(dev);
575 u16 ret;
576
577 rcu_read_lock();
578 if (rcu_dereference(tun->steering_prog))
579 ret = tun_ebpf_select_queue(tun, skb);
580 else
581 ret = tun_automq_select_queue(tun, skb);
582 rcu_read_unlock();
583
584 return ret;
585}
586
587static inline bool tun_not_capable(struct tun_struct *tun)
588{
589 const struct cred *cred = current_cred();
590 struct net *net = dev_net(tun->dev);
591
592 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
593 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
594 !ns_capable(net->user_ns, CAP_NET_ADMIN);
595}
596
597static void tun_set_real_num_queues(struct tun_struct *tun)
598{
599 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
600 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
601}
602
603static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
604{
605 tfile->detached = tun;
606 list_add_tail(&tfile->next, &tun->disabled);
607 ++tun->numdisabled;
608}
609
610static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
611{
612 struct tun_struct *tun = tfile->detached;
613
614 tfile->detached = NULL;
615 list_del_init(&tfile->next);
616 --tun->numdisabled;
617 return tun;
618}
619
620void tun_ptr_free(void *ptr)
621{
622 if (!ptr)
623 return;
624 if (tun_is_xdp_frame(ptr)) {
625 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
626
627 xdp_return_frame(xdpf);
628 } else {
629 __skb_array_destroy_skb(ptr);
630 }
631}
632EXPORT_SYMBOL_GPL(tun_ptr_free);
633
634static void tun_queue_purge(struct tun_file *tfile)
635{
636 void *ptr;
637
638 while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
639 tun_ptr_free(ptr);
640
641 skb_queue_purge(&tfile->sk.sk_write_queue);
642 skb_queue_purge(&tfile->sk.sk_error_queue);
643}
644
645static void __tun_detach(struct tun_file *tfile, bool clean)
646{
647 struct tun_file *ntfile;
648 struct tun_struct *tun;
649
650 tun = rtnl_dereference(tfile->tun);
651
652 if (tun && clean) {
653 tun_napi_disable(tfile);
654 tun_napi_del(tfile);
655 }
656
657 if (tun && !tfile->detached) {
658 u16 index = tfile->queue_index;
659 BUG_ON(index >= tun->numqueues);
660
661 rcu_assign_pointer(tun->tfiles[index],
662 tun->tfiles[tun->numqueues - 1]);
663 ntfile = rtnl_dereference(tun->tfiles[index]);
664 ntfile->queue_index = index;
665 rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
666 NULL);
667
668 --tun->numqueues;
669 if (clean) {
670 RCU_INIT_POINTER(tfile->tun, NULL);
671 sock_put(&tfile->sk);
672 } else
673 tun_disable_queue(tun, tfile);
674
675 synchronize_net();
676 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
677 /* Drop read queue */
678 tun_queue_purge(tfile);
679 tun_set_real_num_queues(tun);
680 } else if (tfile->detached && clean) {
681 tun = tun_enable_queue(tfile);
682 sock_put(&tfile->sk);
683 }
684
685 if (clean) {
686 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
687 netif_carrier_off(tun->dev);
688
689 if (!(tun->flags & IFF_PERSIST) &&
690 tun->dev->reg_state == NETREG_REGISTERED)
691 unregister_netdevice(tun->dev);
692 }
693 if (tun)
694 xdp_rxq_info_unreg(&tfile->xdp_rxq);
695 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
696 sock_put(&tfile->sk);
697 }
698}
699
700static void tun_detach(struct tun_file *tfile, bool clean)
701{
702 struct tun_struct *tun;
703 struct net_device *dev;
704
705 rtnl_lock();
706 tun = rtnl_dereference(tfile->tun);
707 dev = tun ? tun->dev : NULL;
708 __tun_detach(tfile, clean);
709 if (dev)
710 netdev_state_change(dev);
711 rtnl_unlock();
712}
713
714static void tun_detach_all(struct net_device *dev)
715{
716 struct tun_struct *tun = netdev_priv(dev);
717 struct tun_file *tfile, *tmp;
718 int i, n = tun->numqueues;
719
720 for (i = 0; i < n; i++) {
721 tfile = rtnl_dereference(tun->tfiles[i]);
722 BUG_ON(!tfile);
723 tun_napi_disable(tfile);
724 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
725 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
726 RCU_INIT_POINTER(tfile->tun, NULL);
727 --tun->numqueues;
728 }
729 list_for_each_entry(tfile, &tun->disabled, next) {
730 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
731 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
732 RCU_INIT_POINTER(tfile->tun, NULL);
733 }
734 BUG_ON(tun->numqueues != 0);
735
736 synchronize_net();
737 for (i = 0; i < n; i++) {
738 tfile = rtnl_dereference(tun->tfiles[i]);
739 tun_napi_del(tfile);
740 /* Drop read queue */
741 tun_queue_purge(tfile);
742 xdp_rxq_info_unreg(&tfile->xdp_rxq);
743 sock_put(&tfile->sk);
744 }
745 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
746 tun_enable_queue(tfile);
747 tun_queue_purge(tfile);
748 xdp_rxq_info_unreg(&tfile->xdp_rxq);
749 sock_put(&tfile->sk);
750 }
751 BUG_ON(tun->numdisabled != 0);
752
753 if (tun->flags & IFF_PERSIST)
754 module_put(THIS_MODULE);
755}
756
757static int tun_attach(struct tun_struct *tun, struct file *file,
758 bool skip_filter, bool napi, bool napi_frags,
759 bool publish_tun)
760{
761 struct tun_file *tfile = file->private_data;
762 struct net_device *dev = tun->dev;
763 int err;
764
765 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
766 if (err < 0)
767 goto out;
768
769 err = -EINVAL;
770 if (rtnl_dereference(tfile->tun) && !tfile->detached)
771 goto out;
772
773 err = -EBUSY;
774 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
775 goto out;
776
777 err = -E2BIG;
778 if (!tfile->detached &&
779 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
780 goto out;
781
782 err = 0;
783
784 /* Re-attach the filter to persist device */
785 if (!skip_filter && (tun->filter_attached == true)) {
786 lock_sock(tfile->socket.sk);
787 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
788 release_sock(tfile->socket.sk);
789 if (!err)
790 goto out;
791 }
792
793 if (!tfile->detached &&
794 ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
795 GFP_KERNEL, tun_ptr_free)) {
796 err = -ENOMEM;
797 goto out;
798 }
799
800 tfile->queue_index = tun->numqueues;
801 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
802
803 if (tfile->detached) {
804 /* Re-attach detached tfile, updating XDP queue_index */
805 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
806
807 if (tfile->xdp_rxq.queue_index != tfile->queue_index)
808 tfile->xdp_rxq.queue_index = tfile->queue_index;
809 } else {
810 /* Setup XDP RX-queue info, for new tfile getting attached */
811 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
812 tun->dev, tfile->queue_index);
813 if (err < 0)
814 goto out;
815 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
816 MEM_TYPE_PAGE_SHARED, NULL);
817 if (err < 0) {
818 xdp_rxq_info_unreg(&tfile->xdp_rxq);
819 goto out;
820 }
821 err = 0;
822 }
823
824 if (tfile->detached) {
825 tun_enable_queue(tfile);
826 } else {
827 sock_hold(&tfile->sk);
828 tun_napi_init(tun, tfile, napi, napi_frags);
829 }
830
831 if (rtnl_dereference(tun->xdp_prog))
832 sock_set_flag(&tfile->sk, SOCK_XDP);
833
834 /* device is allowed to go away first, so no need to hold extra
835 * refcnt.
836 */
837
838 /* Publish tfile->tun and tun->tfiles only after we've fully
839 * initialized tfile; otherwise we risk using half-initialized
840 * object.
841 */
842 if (publish_tun)
843 rcu_assign_pointer(tfile->tun, tun);
844 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
845 tun->numqueues++;
846 tun_set_real_num_queues(tun);
847out:
848 return err;
849}
850
851static struct tun_struct *tun_get(struct tun_file *tfile)
852{
853 struct tun_struct *tun;
854
855 rcu_read_lock();
856 tun = rcu_dereference(tfile->tun);
857 if (tun)
858 dev_hold(tun->dev);
859 rcu_read_unlock();
860
861 return tun;
862}
863
864static void tun_put(struct tun_struct *tun)
865{
866 dev_put(tun->dev);
867}
868
869/* TAP filtering */
870static void addr_hash_set(u32 *mask, const u8 *addr)
871{
872 int n = ether_crc(ETH_ALEN, addr) >> 26;
873 mask[n >> 5] |= (1 << (n & 31));
874}
875
876static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
877{
878 int n = ether_crc(ETH_ALEN, addr) >> 26;
879 return mask[n >> 5] & (1 << (n & 31));
880}
881
882static int update_filter(struct tap_filter *filter, void __user *arg)
883{
884 struct { u8 u[ETH_ALEN]; } *addr;
885 struct tun_filter uf;
886 int err, alen, n, nexact;
887
888 if (copy_from_user(&uf, arg, sizeof(uf)))
889 return -EFAULT;
890
891 if (!uf.count) {
892 /* Disabled */
893 filter->count = 0;
894 return 0;
895 }
896
897 alen = ETH_ALEN * uf.count;
898 addr = memdup_user(arg + sizeof(uf), alen);
899 if (IS_ERR(addr))
900 return PTR_ERR(addr);
901
902 /* The filter is updated without holding any locks. Which is
903 * perfectly safe. We disable it first and in the worst
904 * case we'll accept a few undesired packets. */
905 filter->count = 0;
906 wmb();
907
908 /* Use first set of addresses as an exact filter */
909 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
910 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
911
912 nexact = n;
913
914 /* Remaining multicast addresses are hashed,
915 * unicast will leave the filter disabled. */
916 memset(filter->mask, 0, sizeof(filter->mask));
917 for (; n < uf.count; n++) {
918 if (!is_multicast_ether_addr(addr[n].u)) {
919 err = 0; /* no filter */
920 goto free_addr;
921 }
922 addr_hash_set(filter->mask, addr[n].u);
923 }
924
925 /* For ALLMULTI just set the mask to all ones.
926 * This overrides the mask populated above. */
927 if ((uf.flags & TUN_FLT_ALLMULTI))
928 memset(filter->mask, ~0, sizeof(filter->mask));
929
930 /* Now enable the filter */
931 wmb();
932 filter->count = nexact;
933
934 /* Return the number of exact filters */
935 err = nexact;
936free_addr:
937 kfree(addr);
938 return err;
939}
940
941/* Returns: 0 - drop, !=0 - accept */
942static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
943{
944 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
945 * at this point. */
946 struct ethhdr *eh = (struct ethhdr *) skb->data;
947 int i;
948
949 /* Exact match */
950 for (i = 0; i < filter->count; i++)
951 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
952 return 1;
953
954 /* Inexact match (multicast only) */
955 if (is_multicast_ether_addr(eh->h_dest))
956 return addr_hash_test(filter->mask, eh->h_dest);
957
958 return 0;
959}
960
961/*
962 * Checks whether the packet is accepted or not.
963 * Returns: 0 - drop, !=0 - accept
964 */
965static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
966{
967 if (!filter->count)
968 return 1;
969
970 return run_filter(filter, skb);
971}
972
973/* Network device part of the driver */
974
975static const struct ethtool_ops tun_ethtool_ops;
976
977/* Net device detach from fd. */
978static void tun_net_uninit(struct net_device *dev)
979{
980 tun_detach_all(dev);
981}
982
983/* Net device open. */
984static int tun_net_open(struct net_device *dev)
985{
986 netif_tx_start_all_queues(dev);
987
988 return 0;
989}
990
991/* Net device close. */
992static int tun_net_close(struct net_device *dev)
993{
994 netif_tx_stop_all_queues(dev);
995 return 0;
996}
997
998/* Net device start xmit */
999static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1000{
1001#ifdef CONFIG_RPS
1002 if (tun->numqueues == 1 && static_branch_unlikely(&rps_needed)) {
1003 /* Select queue was not called for the skbuff, so we extract the
1004 * RPS hash and save it into the flow_table here.
1005 */
1006 struct tun_flow_entry *e;
1007 __u32 rxhash;
1008
1009 rxhash = __skb_get_hash_symmetric(skb);
1010 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
1011 if (e)
1012 tun_flow_save_rps_rxhash(e, rxhash);
1013 }
1014#endif
1015}
1016
1017static unsigned int run_ebpf_filter(struct tun_struct *tun,
1018 struct sk_buff *skb,
1019 int len)
1020{
1021 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1022
1023 if (prog)
1024 len = bpf_prog_run_clear_cb(prog->prog, skb);
1025
1026 return len;
1027}
1028
1029/* Net device start xmit */
1030static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1031{
1032 struct tun_struct *tun = netdev_priv(dev);
1033 int txq = skb->queue_mapping;
1034 struct tun_file *tfile;
1035 int len = skb->len;
1036
1037 rcu_read_lock();
1038 tfile = rcu_dereference(tun->tfiles[txq]);
1039
1040 /* Drop packet if interface is not attached */
1041 if (!tfile)
1042 goto drop;
1043
1044 if (!rcu_dereference(tun->steering_prog))
1045 tun_automq_xmit(tun, skb);
1046
1047 netif_info(tun, tx_queued, tun->dev, "%s %d\n", __func__, skb->len);
1048
1049 /* Drop if the filter does not like it.
1050 * This is a noop if the filter is disabled.
1051 * Filter can be enabled only for the TAP devices. */
1052 if (!check_filter(&tun->txflt, skb))
1053 goto drop;
1054
1055 if (tfile->socket.sk->sk_filter &&
1056 sk_filter(tfile->socket.sk, skb))
1057 goto drop;
1058
1059 len = run_ebpf_filter(tun, skb, len);
1060 if (len == 0 || pskb_trim(skb, len))
1061 goto drop;
1062
1063 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1064 goto drop;
1065
1066 skb_tx_timestamp(skb);
1067
1068 /* Orphan the skb - required as we might hang on to it
1069 * for indefinite time.
1070 */
1071 skb_orphan(skb);
1072
1073 nf_reset_ct(skb);
1074
1075 if (ptr_ring_produce(&tfile->tx_ring, skb))
1076 goto drop;
1077
1078 /* Notify and wake up reader process */
1079 if (tfile->flags & TUN_FASYNC)
1080 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1081 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1082
1083 rcu_read_unlock();
1084 return NETDEV_TX_OK;
1085
1086drop:
1087 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1088 skb_tx_error(skb);
1089 kfree_skb(skb);
1090 rcu_read_unlock();
1091 return NET_XMIT_DROP;
1092}
1093
1094static void tun_net_mclist(struct net_device *dev)
1095{
1096 /*
1097 * This callback is supposed to deal with mc filter in
1098 * _rx_ path and has nothing to do with the _tx_ path.
1099 * In rx path we always accept everything userspace gives us.
1100 */
1101}
1102
1103static netdev_features_t tun_net_fix_features(struct net_device *dev,
1104 netdev_features_t features)
1105{
1106 struct tun_struct *tun = netdev_priv(dev);
1107
1108 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1109}
1110
1111static void tun_set_headroom(struct net_device *dev, int new_hr)
1112{
1113 struct tun_struct *tun = netdev_priv(dev);
1114
1115 if (new_hr < NET_SKB_PAD)
1116 new_hr = NET_SKB_PAD;
1117
1118 tun->align = new_hr;
1119}
1120
1121static void
1122tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1123{
1124 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1125 struct tun_struct *tun = netdev_priv(dev);
1126 struct tun_pcpu_stats *p;
1127 int i;
1128
1129 for_each_possible_cpu(i) {
1130 u64 rxpackets, rxbytes, txpackets, txbytes;
1131 unsigned int start;
1132
1133 p = per_cpu_ptr(tun->pcpu_stats, i);
1134 do {
1135 start = u64_stats_fetch_begin(&p->syncp);
1136 rxpackets = u64_stats_read(&p->rx_packets);
1137 rxbytes = u64_stats_read(&p->rx_bytes);
1138 txpackets = u64_stats_read(&p->tx_packets);
1139 txbytes = u64_stats_read(&p->tx_bytes);
1140 } while (u64_stats_fetch_retry(&p->syncp, start));
1141
1142 stats->rx_packets += rxpackets;
1143 stats->rx_bytes += rxbytes;
1144 stats->tx_packets += txpackets;
1145 stats->tx_bytes += txbytes;
1146
1147 /* u32 counters */
1148 rx_dropped += p->rx_dropped;
1149 rx_frame_errors += p->rx_frame_errors;
1150 tx_dropped += p->tx_dropped;
1151 }
1152 stats->rx_dropped = rx_dropped;
1153 stats->rx_frame_errors = rx_frame_errors;
1154 stats->tx_dropped = tx_dropped;
1155}
1156
1157static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1158 struct netlink_ext_ack *extack)
1159{
1160 struct tun_struct *tun = netdev_priv(dev);
1161 struct tun_file *tfile;
1162 struct bpf_prog *old_prog;
1163 int i;
1164
1165 old_prog = rtnl_dereference(tun->xdp_prog);
1166 rcu_assign_pointer(tun->xdp_prog, prog);
1167 if (old_prog)
1168 bpf_prog_put(old_prog);
1169
1170 for (i = 0; i < tun->numqueues; i++) {
1171 tfile = rtnl_dereference(tun->tfiles[i]);
1172 if (prog)
1173 sock_set_flag(&tfile->sk, SOCK_XDP);
1174 else
1175 sock_reset_flag(&tfile->sk, SOCK_XDP);
1176 }
1177 list_for_each_entry(tfile, &tun->disabled, next) {
1178 if (prog)
1179 sock_set_flag(&tfile->sk, SOCK_XDP);
1180 else
1181 sock_reset_flag(&tfile->sk, SOCK_XDP);
1182 }
1183
1184 return 0;
1185}
1186
1187static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1188{
1189 switch (xdp->command) {
1190 case XDP_SETUP_PROG:
1191 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1192 default:
1193 return -EINVAL;
1194 }
1195}
1196
1197static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1198{
1199 if (new_carrier) {
1200 struct tun_struct *tun = netdev_priv(dev);
1201
1202 if (!tun->numqueues)
1203 return -EPERM;
1204
1205 netif_carrier_on(dev);
1206 } else {
1207 netif_carrier_off(dev);
1208 }
1209 return 0;
1210}
1211
1212static const struct net_device_ops tun_netdev_ops = {
1213 .ndo_uninit = tun_net_uninit,
1214 .ndo_open = tun_net_open,
1215 .ndo_stop = tun_net_close,
1216 .ndo_start_xmit = tun_net_xmit,
1217 .ndo_fix_features = tun_net_fix_features,
1218 .ndo_select_queue = tun_select_queue,
1219 .ndo_set_rx_headroom = tun_set_headroom,
1220 .ndo_get_stats64 = tun_net_get_stats64,
1221 .ndo_change_carrier = tun_net_change_carrier,
1222};
1223
1224static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1225{
1226 /* Notify and wake up reader process */
1227 if (tfile->flags & TUN_FASYNC)
1228 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1229 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1230}
1231
1232static int tun_xdp_xmit(struct net_device *dev, int n,
1233 struct xdp_frame **frames, u32 flags)
1234{
1235 struct tun_struct *tun = netdev_priv(dev);
1236 struct tun_file *tfile;
1237 u32 numqueues;
1238 int drops = 0;
1239 int cnt = n;
1240 int i;
1241
1242 if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1243 return -EINVAL;
1244
1245 rcu_read_lock();
1246
1247resample:
1248 numqueues = READ_ONCE(tun->numqueues);
1249 if (!numqueues) {
1250 rcu_read_unlock();
1251 return -ENXIO; /* Caller will free/return all frames */
1252 }
1253
1254 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1255 numqueues]);
1256 if (unlikely(!tfile))
1257 goto resample;
1258
1259 spin_lock(&tfile->tx_ring.producer_lock);
1260 for (i = 0; i < n; i++) {
1261 struct xdp_frame *xdp = frames[i];
1262 /* Encode the XDP flag into lowest bit for consumer to differ
1263 * XDP buffer from sk_buff.
1264 */
1265 void *frame = tun_xdp_to_ptr(xdp);
1266
1267 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1268 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1269 xdp_return_frame_rx_napi(xdp);
1270 drops++;
1271 }
1272 }
1273 spin_unlock(&tfile->tx_ring.producer_lock);
1274
1275 if (flags & XDP_XMIT_FLUSH)
1276 __tun_xdp_flush_tfile(tfile);
1277
1278 rcu_read_unlock();
1279 return cnt - drops;
1280}
1281
1282static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1283{
1284 struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
1285
1286 if (unlikely(!frame))
1287 return -EOVERFLOW;
1288
1289 return tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1290}
1291
1292static const struct net_device_ops tap_netdev_ops = {
1293 .ndo_uninit = tun_net_uninit,
1294 .ndo_open = tun_net_open,
1295 .ndo_stop = tun_net_close,
1296 .ndo_start_xmit = tun_net_xmit,
1297 .ndo_fix_features = tun_net_fix_features,
1298 .ndo_set_rx_mode = tun_net_mclist,
1299 .ndo_set_mac_address = eth_mac_addr,
1300 .ndo_validate_addr = eth_validate_addr,
1301 .ndo_select_queue = tun_select_queue,
1302 .ndo_features_check = passthru_features_check,
1303 .ndo_set_rx_headroom = tun_set_headroom,
1304 .ndo_get_stats64 = tun_net_get_stats64,
1305 .ndo_bpf = tun_xdp,
1306 .ndo_xdp_xmit = tun_xdp_xmit,
1307 .ndo_change_carrier = tun_net_change_carrier,
1308};
1309
1310static void tun_flow_init(struct tun_struct *tun)
1311{
1312 int i;
1313
1314 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1315 INIT_HLIST_HEAD(&tun->flows[i]);
1316
1317 tun->ageing_time = TUN_FLOW_EXPIRE;
1318 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1319 mod_timer(&tun->flow_gc_timer,
1320 round_jiffies_up(jiffies + tun->ageing_time));
1321}
1322
1323static void tun_flow_uninit(struct tun_struct *tun)
1324{
1325 del_timer_sync(&tun->flow_gc_timer);
1326 tun_flow_flush(tun);
1327}
1328
1329#define MIN_MTU 68
1330#define MAX_MTU 65535
1331
1332/* Initialize net device. */
1333static void tun_net_init(struct net_device *dev)
1334{
1335 struct tun_struct *tun = netdev_priv(dev);
1336
1337 switch (tun->flags & TUN_TYPE_MASK) {
1338 case IFF_TUN:
1339 dev->netdev_ops = &tun_netdev_ops;
1340 dev->header_ops = &ip_tunnel_header_ops;
1341
1342 /* Point-to-Point TUN Device */
1343 dev->hard_header_len = 0;
1344 dev->addr_len = 0;
1345 dev->mtu = 1500;
1346
1347 /* Zero header length */
1348 dev->type = ARPHRD_NONE;
1349 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1350 break;
1351
1352 case IFF_TAP:
1353 dev->netdev_ops = &tap_netdev_ops;
1354 /* Ethernet TAP Device */
1355 ether_setup(dev);
1356 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1357 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1358
1359 eth_hw_addr_random(dev);
1360
1361 break;
1362 }
1363
1364 dev->min_mtu = MIN_MTU;
1365 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1366}
1367
1368static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1369{
1370 struct sock *sk = tfile->socket.sk;
1371
1372 return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1373}
1374
1375/* Character device part */
1376
1377/* Poll */
1378static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1379{
1380 struct tun_file *tfile = file->private_data;
1381 struct tun_struct *tun = tun_get(tfile);
1382 struct sock *sk;
1383 __poll_t mask = 0;
1384
1385 if (!tun)
1386 return EPOLLERR;
1387
1388 sk = tfile->socket.sk;
1389
1390 poll_wait(file, sk_sleep(sk), wait);
1391
1392 if (!ptr_ring_empty(&tfile->tx_ring))
1393 mask |= EPOLLIN | EPOLLRDNORM;
1394
1395 /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1396 * guarantee EPOLLOUT to be raised by either here or
1397 * tun_sock_write_space(). Then process could get notification
1398 * after it writes to a down device and meets -EIO.
1399 */
1400 if (tun_sock_writeable(tun, tfile) ||
1401 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1402 tun_sock_writeable(tun, tfile)))
1403 mask |= EPOLLOUT | EPOLLWRNORM;
1404
1405 if (tun->dev->reg_state != NETREG_REGISTERED)
1406 mask = EPOLLERR;
1407
1408 tun_put(tun);
1409 return mask;
1410}
1411
1412static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1413 size_t len,
1414 const struct iov_iter *it)
1415{
1416 struct sk_buff *skb;
1417 size_t linear;
1418 int err;
1419 int i;
1420
1421 if (it->nr_segs > MAX_SKB_FRAGS + 1)
1422 return ERR_PTR(-ENOMEM);
1423
1424 local_bh_disable();
1425 skb = napi_get_frags(&tfile->napi);
1426 local_bh_enable();
1427 if (!skb)
1428 return ERR_PTR(-ENOMEM);
1429
1430 linear = iov_iter_single_seg_count(it);
1431 err = __skb_grow(skb, linear);
1432 if (err)
1433 goto free;
1434
1435 skb->len = len;
1436 skb->data_len = len - linear;
1437 skb->truesize += skb->data_len;
1438
1439 for (i = 1; i < it->nr_segs; i++) {
1440 size_t fragsz = it->iov[i].iov_len;
1441 struct page *page;
1442 void *frag;
1443
1444 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1445 err = -EINVAL;
1446 goto free;
1447 }
1448 frag = netdev_alloc_frag(fragsz);
1449 if (!frag) {
1450 err = -ENOMEM;
1451 goto free;
1452 }
1453 page = virt_to_head_page(frag);
1454 skb_fill_page_desc(skb, i - 1, page,
1455 frag - page_address(page), fragsz);
1456 }
1457
1458 return skb;
1459free:
1460 /* frees skb and all frags allocated with napi_alloc_frag() */
1461 napi_free_frags(&tfile->napi);
1462 return ERR_PTR(err);
1463}
1464
1465/* prepad is the amount to reserve at front. len is length after that.
1466 * linear is a hint as to how much to copy (usually headers). */
1467static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1468 size_t prepad, size_t len,
1469 size_t linear, int noblock)
1470{
1471 struct sock *sk = tfile->socket.sk;
1472 struct sk_buff *skb;
1473 int err;
1474
1475 /* Under a page? Don't bother with paged skb. */
1476 if (prepad + len < PAGE_SIZE || !linear)
1477 linear = len;
1478
1479 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1480 &err, 0);
1481 if (!skb)
1482 return ERR_PTR(err);
1483
1484 skb_reserve(skb, prepad);
1485 skb_put(skb, linear);
1486 skb->data_len = len - linear;
1487 skb->len += len - linear;
1488
1489 return skb;
1490}
1491
1492static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1493 struct sk_buff *skb, int more)
1494{
1495 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1496 struct sk_buff_head process_queue;
1497 u32 rx_batched = tun->rx_batched;
1498 bool rcv = false;
1499
1500 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1501 local_bh_disable();
1502 skb_record_rx_queue(skb, tfile->queue_index);
1503 netif_receive_skb(skb);
1504 local_bh_enable();
1505 return;
1506 }
1507
1508 spin_lock(&queue->lock);
1509 if (!more || skb_queue_len(queue) == rx_batched) {
1510 __skb_queue_head_init(&process_queue);
1511 skb_queue_splice_tail_init(queue, &process_queue);
1512 rcv = true;
1513 } else {
1514 __skb_queue_tail(queue, skb);
1515 }
1516 spin_unlock(&queue->lock);
1517
1518 if (rcv) {
1519 struct sk_buff *nskb;
1520
1521 local_bh_disable();
1522 while ((nskb = __skb_dequeue(&process_queue))) {
1523 skb_record_rx_queue(nskb, tfile->queue_index);
1524 netif_receive_skb(nskb);
1525 }
1526 skb_record_rx_queue(skb, tfile->queue_index);
1527 netif_receive_skb(skb);
1528 local_bh_enable();
1529 }
1530}
1531
1532static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1533 int len, int noblock, bool zerocopy)
1534{
1535 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1536 return false;
1537
1538 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1539 return false;
1540
1541 if (!noblock)
1542 return false;
1543
1544 if (zerocopy)
1545 return false;
1546
1547 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1548 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1549 return false;
1550
1551 return true;
1552}
1553
1554static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
1555 struct page_frag *alloc_frag, char *buf,
1556 int buflen, int len, int pad)
1557{
1558 struct sk_buff *skb = build_skb(buf, buflen);
1559
1560 if (!skb)
1561 return ERR_PTR(-ENOMEM);
1562
1563 skb_reserve(skb, pad);
1564 skb_put(skb, len);
1565 skb_set_owner_w(skb, tfile->socket.sk);
1566
1567 get_page(alloc_frag->page);
1568 alloc_frag->offset += buflen;
1569
1570 return skb;
1571}
1572
1573static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1574 struct xdp_buff *xdp, u32 act)
1575{
1576 int err;
1577
1578 switch (act) {
1579 case XDP_REDIRECT:
1580 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1581 if (err)
1582 return err;
1583 break;
1584 case XDP_TX:
1585 err = tun_xdp_tx(tun->dev, xdp);
1586 if (err < 0)
1587 return err;
1588 break;
1589 case XDP_PASS:
1590 break;
1591 default:
1592 bpf_warn_invalid_xdp_action(act);
1593 fallthrough;
1594 case XDP_ABORTED:
1595 trace_xdp_exception(tun->dev, xdp_prog, act);
1596 fallthrough;
1597 case XDP_DROP:
1598 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1599 break;
1600 }
1601
1602 return act;
1603}
1604
1605static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1606 struct tun_file *tfile,
1607 struct iov_iter *from,
1608 struct virtio_net_hdr *hdr,
1609 int len, int *skb_xdp)
1610{
1611 struct page_frag *alloc_frag = ¤t->task_frag;
1612 struct bpf_prog *xdp_prog;
1613 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1614 char *buf;
1615 size_t copied;
1616 int pad = TUN_RX_PAD;
1617 int err = 0;
1618
1619 rcu_read_lock();
1620 xdp_prog = rcu_dereference(tun->xdp_prog);
1621 if (xdp_prog)
1622 pad += XDP_PACKET_HEADROOM;
1623 buflen += SKB_DATA_ALIGN(len + pad);
1624 rcu_read_unlock();
1625
1626 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1627 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1628 return ERR_PTR(-ENOMEM);
1629
1630 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1631 copied = copy_page_from_iter(alloc_frag->page,
1632 alloc_frag->offset + pad,
1633 len, from);
1634 if (copied != len)
1635 return ERR_PTR(-EFAULT);
1636
1637 /* There's a small window that XDP may be set after the check
1638 * of xdp_prog above, this should be rare and for simplicity
1639 * we do XDP on skb in case the headroom is not enough.
1640 */
1641 if (hdr->gso_type || !xdp_prog) {
1642 *skb_xdp = 1;
1643 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len,
1644 pad);
1645 }
1646
1647 *skb_xdp = 0;
1648
1649 local_bh_disable();
1650 rcu_read_lock();
1651 xdp_prog = rcu_dereference(tun->xdp_prog);
1652 if (xdp_prog) {
1653 struct xdp_buff xdp;
1654 u32 act;
1655
1656 xdp.data_hard_start = buf;
1657 xdp.data = buf + pad;
1658 xdp_set_data_meta_invalid(&xdp);
1659 xdp.data_end = xdp.data + len;
1660 xdp.rxq = &tfile->xdp_rxq;
1661 xdp.frame_sz = buflen;
1662
1663 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1664 if (act == XDP_REDIRECT || act == XDP_TX) {
1665 get_page(alloc_frag->page);
1666 alloc_frag->offset += buflen;
1667 }
1668 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1669 if (err < 0) {
1670 if (act == XDP_REDIRECT || act == XDP_TX)
1671 put_page(alloc_frag->page);
1672 goto out;
1673 }
1674
1675 if (err == XDP_REDIRECT)
1676 xdp_do_flush();
1677 if (err != XDP_PASS)
1678 goto out;
1679
1680 pad = xdp.data - xdp.data_hard_start;
1681 len = xdp.data_end - xdp.data;
1682 }
1683 rcu_read_unlock();
1684 local_bh_enable();
1685
1686 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1687
1688out:
1689 rcu_read_unlock();
1690 local_bh_enable();
1691 return NULL;
1692}
1693
1694/* Get packet from user space buffer */
1695static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1696 void *msg_control, struct iov_iter *from,
1697 int noblock, bool more)
1698{
1699 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1700 struct sk_buff *skb;
1701 size_t total_len = iov_iter_count(from);
1702 size_t len = total_len, align = tun->align, linear;
1703 struct virtio_net_hdr gso = { 0 };
1704 struct tun_pcpu_stats *stats;
1705 int good_linear;
1706 int copylen;
1707 bool zerocopy = false;
1708 int err;
1709 u32 rxhash = 0;
1710 int skb_xdp = 1;
1711 bool frags = tun_napi_frags_enabled(tfile);
1712
1713 if (!(tun->flags & IFF_NO_PI)) {
1714 if (len < sizeof(pi))
1715 return -EINVAL;
1716 len -= sizeof(pi);
1717
1718 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1719 return -EFAULT;
1720 }
1721
1722 if (tun->flags & IFF_VNET_HDR) {
1723 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1724
1725 if (len < vnet_hdr_sz)
1726 return -EINVAL;
1727 len -= vnet_hdr_sz;
1728
1729 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1730 return -EFAULT;
1731
1732 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1733 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1734 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1735
1736 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1737 return -EINVAL;
1738 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1739 }
1740
1741 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1742 align += NET_IP_ALIGN;
1743 if (unlikely(len < ETH_HLEN ||
1744 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1745 return -EINVAL;
1746 }
1747
1748 good_linear = SKB_MAX_HEAD(align);
1749
1750 if (msg_control) {
1751 struct iov_iter i = *from;
1752
1753 /* There are 256 bytes to be copied in skb, so there is
1754 * enough room for skb expand head in case it is used.
1755 * The rest of the buffer is mapped from userspace.
1756 */
1757 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1758 if (copylen > good_linear)
1759 copylen = good_linear;
1760 linear = copylen;
1761 iov_iter_advance(&i, copylen);
1762 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1763 zerocopy = true;
1764 }
1765
1766 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1767 /* For the packet that is not easy to be processed
1768 * (e.g gso or jumbo packet), we will do it at after
1769 * skb was created with generic XDP routine.
1770 */
1771 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1772 if (IS_ERR(skb)) {
1773 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1774 return PTR_ERR(skb);
1775 }
1776 if (!skb)
1777 return total_len;
1778 } else {
1779 if (!zerocopy) {
1780 copylen = len;
1781 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1782 linear = good_linear;
1783 else
1784 linear = tun16_to_cpu(tun, gso.hdr_len);
1785 }
1786
1787 if (frags) {
1788 mutex_lock(&tfile->napi_mutex);
1789 skb = tun_napi_alloc_frags(tfile, copylen, from);
1790 /* tun_napi_alloc_frags() enforces a layout for the skb.
1791 * If zerocopy is enabled, then this layout will be
1792 * overwritten by zerocopy_sg_from_iter().
1793 */
1794 zerocopy = false;
1795 } else {
1796 skb = tun_alloc_skb(tfile, align, copylen, linear,
1797 noblock);
1798 }
1799
1800 if (IS_ERR(skb)) {
1801 if (PTR_ERR(skb) != -EAGAIN)
1802 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1803 if (frags)
1804 mutex_unlock(&tfile->napi_mutex);
1805 return PTR_ERR(skb);
1806 }
1807
1808 if (zerocopy)
1809 err = zerocopy_sg_from_iter(skb, from);
1810 else
1811 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1812
1813 if (err) {
1814 err = -EFAULT;
1815drop:
1816 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1817 kfree_skb(skb);
1818 if (frags) {
1819 tfile->napi.skb = NULL;
1820 mutex_unlock(&tfile->napi_mutex);
1821 }
1822
1823 return err;
1824 }
1825 }
1826
1827 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1828 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1829 kfree_skb(skb);
1830 if (frags) {
1831 tfile->napi.skb = NULL;
1832 mutex_unlock(&tfile->napi_mutex);
1833 }
1834
1835 return -EINVAL;
1836 }
1837
1838 switch (tun->flags & TUN_TYPE_MASK) {
1839 case IFF_TUN:
1840 if (tun->flags & IFF_NO_PI) {
1841 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1842
1843 switch (ip_version) {
1844 case 4:
1845 pi.proto = htons(ETH_P_IP);
1846 break;
1847 case 6:
1848 pi.proto = htons(ETH_P_IPV6);
1849 break;
1850 default:
1851 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1852 kfree_skb(skb);
1853 return -EINVAL;
1854 }
1855 }
1856
1857 skb_reset_mac_header(skb);
1858 skb->protocol = pi.proto;
1859 skb->dev = tun->dev;
1860 break;
1861 case IFF_TAP:
1862 if (frags && !pskb_may_pull(skb, ETH_HLEN)) {
1863 err = -ENOMEM;
1864 goto drop;
1865 }
1866 skb->protocol = eth_type_trans(skb, tun->dev);
1867 break;
1868 }
1869
1870 /* copy skb_ubuf_info for callback when skb has no error */
1871 if (zerocopy) {
1872 skb_shinfo(skb)->destructor_arg = msg_control;
1873 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1874 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1875 } else if (msg_control) {
1876 struct ubuf_info *uarg = msg_control;
1877 uarg->callback(uarg, false);
1878 }
1879
1880 skb_reset_network_header(skb);
1881 skb_probe_transport_header(skb);
1882 skb_record_rx_queue(skb, tfile->queue_index);
1883
1884 if (skb_xdp) {
1885 struct bpf_prog *xdp_prog;
1886 int ret;
1887
1888 local_bh_disable();
1889 rcu_read_lock();
1890 xdp_prog = rcu_dereference(tun->xdp_prog);
1891 if (xdp_prog) {
1892 ret = do_xdp_generic(xdp_prog, skb);
1893 if (ret != XDP_PASS) {
1894 rcu_read_unlock();
1895 local_bh_enable();
1896 if (frags) {
1897 tfile->napi.skb = NULL;
1898 mutex_unlock(&tfile->napi_mutex);
1899 }
1900 return total_len;
1901 }
1902 }
1903 rcu_read_unlock();
1904 local_bh_enable();
1905 }
1906
1907 /* Compute the costly rx hash only if needed for flow updates.
1908 * We may get a very small possibility of OOO during switching, not
1909 * worth to optimize.
1910 */
1911 if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1912 !tfile->detached)
1913 rxhash = __skb_get_hash_symmetric(skb);
1914
1915 rcu_read_lock();
1916 if (unlikely(!(tun->dev->flags & IFF_UP))) {
1917 err = -EIO;
1918 rcu_read_unlock();
1919 goto drop;
1920 }
1921
1922 if (frags) {
1923 u32 headlen;
1924
1925 /* Exercise flow dissector code path. */
1926 skb_push(skb, ETH_HLEN);
1927 headlen = eth_get_headlen(tun->dev, skb->data,
1928 skb_headlen(skb));
1929
1930 if (unlikely(headlen > skb_headlen(skb))) {
1931 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1932 napi_free_frags(&tfile->napi);
1933 rcu_read_unlock();
1934 mutex_unlock(&tfile->napi_mutex);
1935 WARN_ON(1);
1936 return -ENOMEM;
1937 }
1938
1939 local_bh_disable();
1940 napi_gro_frags(&tfile->napi);
1941 local_bh_enable();
1942 mutex_unlock(&tfile->napi_mutex);
1943 } else if (tfile->napi_enabled) {
1944 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1945 int queue_len;
1946
1947 spin_lock_bh(&queue->lock);
1948 __skb_queue_tail(queue, skb);
1949 queue_len = skb_queue_len(queue);
1950 spin_unlock(&queue->lock);
1951
1952 if (!more || queue_len > NAPI_POLL_WEIGHT)
1953 napi_schedule(&tfile->napi);
1954
1955 local_bh_enable();
1956 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1957 tun_rx_batched(tun, tfile, skb, more);
1958 } else {
1959 netif_rx_ni(skb);
1960 }
1961 rcu_read_unlock();
1962
1963 stats = get_cpu_ptr(tun->pcpu_stats);
1964 u64_stats_update_begin(&stats->syncp);
1965 u64_stats_inc(&stats->rx_packets);
1966 u64_stats_add(&stats->rx_bytes, len);
1967 u64_stats_update_end(&stats->syncp);
1968 put_cpu_ptr(stats);
1969
1970 if (rxhash)
1971 tun_flow_update(tun, rxhash, tfile);
1972
1973 return total_len;
1974}
1975
1976static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1977{
1978 struct file *file = iocb->ki_filp;
1979 struct tun_file *tfile = file->private_data;
1980 struct tun_struct *tun = tun_get(tfile);
1981 ssize_t result;
1982
1983 if (!tun)
1984 return -EBADFD;
1985
1986 result = tun_get_user(tun, tfile, NULL, from,
1987 file->f_flags & O_NONBLOCK, false);
1988
1989 tun_put(tun);
1990 return result;
1991}
1992
1993static ssize_t tun_put_user_xdp(struct tun_struct *tun,
1994 struct tun_file *tfile,
1995 struct xdp_frame *xdp_frame,
1996 struct iov_iter *iter)
1997{
1998 int vnet_hdr_sz = 0;
1999 size_t size = xdp_frame->len;
2000 struct tun_pcpu_stats *stats;
2001 size_t ret;
2002
2003 if (tun->flags & IFF_VNET_HDR) {
2004 struct virtio_net_hdr gso = { 0 };
2005
2006 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2007 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2008 return -EINVAL;
2009 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2010 sizeof(gso)))
2011 return -EFAULT;
2012 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2013 }
2014
2015 ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2016
2017 stats = get_cpu_ptr(tun->pcpu_stats);
2018 u64_stats_update_begin(&stats->syncp);
2019 u64_stats_inc(&stats->tx_packets);
2020 u64_stats_add(&stats->tx_bytes, ret);
2021 u64_stats_update_end(&stats->syncp);
2022 put_cpu_ptr(tun->pcpu_stats);
2023
2024 return ret;
2025}
2026
2027/* Put packet to the user space buffer */
2028static ssize_t tun_put_user(struct tun_struct *tun,
2029 struct tun_file *tfile,
2030 struct sk_buff *skb,
2031 struct iov_iter *iter)
2032{
2033 struct tun_pi pi = { 0, skb->protocol };
2034 struct tun_pcpu_stats *stats;
2035 ssize_t total;
2036 int vlan_offset = 0;
2037 int vlan_hlen = 0;
2038 int vnet_hdr_sz = 0;
2039
2040 if (skb_vlan_tag_present(skb))
2041 vlan_hlen = VLAN_HLEN;
2042
2043 if (tun->flags & IFF_VNET_HDR)
2044 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2045
2046 total = skb->len + vlan_hlen + vnet_hdr_sz;
2047
2048 if (!(tun->flags & IFF_NO_PI)) {
2049 if (iov_iter_count(iter) < sizeof(pi))
2050 return -EINVAL;
2051
2052 total += sizeof(pi);
2053 if (iov_iter_count(iter) < total) {
2054 /* Packet will be striped */
2055 pi.flags |= TUN_PKT_STRIP;
2056 }
2057
2058 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2059 return -EFAULT;
2060 }
2061
2062 if (vnet_hdr_sz) {
2063 struct virtio_net_hdr gso;
2064
2065 if (iov_iter_count(iter) < vnet_hdr_sz)
2066 return -EINVAL;
2067
2068 if (virtio_net_hdr_from_skb(skb, &gso,
2069 tun_is_little_endian(tun), true,
2070 vlan_hlen)) {
2071 struct skb_shared_info *sinfo = skb_shinfo(skb);
2072 pr_err("unexpected GSO type: "
2073 "0x%x, gso_size %d, hdr_len %d\n",
2074 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2075 tun16_to_cpu(tun, gso.hdr_len));
2076 print_hex_dump(KERN_ERR, "tun: ",
2077 DUMP_PREFIX_NONE,
2078 16, 1, skb->head,
2079 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2080 WARN_ON_ONCE(1);
2081 return -EINVAL;
2082 }
2083
2084 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2085 return -EFAULT;
2086
2087 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2088 }
2089
2090 if (vlan_hlen) {
2091 int ret;
2092 struct veth veth;
2093
2094 veth.h_vlan_proto = skb->vlan_proto;
2095 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2096
2097 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2098
2099 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2100 if (ret || !iov_iter_count(iter))
2101 goto done;
2102
2103 ret = copy_to_iter(&veth, sizeof(veth), iter);
2104 if (ret != sizeof(veth) || !iov_iter_count(iter))
2105 goto done;
2106 }
2107
2108 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2109
2110done:
2111 /* caller is in process context, */
2112 stats = get_cpu_ptr(tun->pcpu_stats);
2113 u64_stats_update_begin(&stats->syncp);
2114 u64_stats_inc(&stats->tx_packets);
2115 u64_stats_add(&stats->tx_bytes, skb->len + vlan_hlen);
2116 u64_stats_update_end(&stats->syncp);
2117 put_cpu_ptr(tun->pcpu_stats);
2118
2119 return total;
2120}
2121
2122static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2123{
2124 DECLARE_WAITQUEUE(wait, current);
2125 void *ptr = NULL;
2126 int error = 0;
2127
2128 ptr = ptr_ring_consume(&tfile->tx_ring);
2129 if (ptr)
2130 goto out;
2131 if (noblock) {
2132 error = -EAGAIN;
2133 goto out;
2134 }
2135
2136 add_wait_queue(&tfile->socket.wq.wait, &wait);
2137
2138 while (1) {
2139 set_current_state(TASK_INTERRUPTIBLE);
2140 ptr = ptr_ring_consume(&tfile->tx_ring);
2141 if (ptr)
2142 break;
2143 if (signal_pending(current)) {
2144 error = -ERESTARTSYS;
2145 break;
2146 }
2147 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2148 error = -EFAULT;
2149 break;
2150 }
2151
2152 schedule();
2153 }
2154
2155 __set_current_state(TASK_RUNNING);
2156 remove_wait_queue(&tfile->socket.wq.wait, &wait);
2157
2158out:
2159 *err = error;
2160 return ptr;
2161}
2162
2163static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2164 struct iov_iter *to,
2165 int noblock, void *ptr)
2166{
2167 ssize_t ret;
2168 int err;
2169
2170 if (!iov_iter_count(to)) {
2171 tun_ptr_free(ptr);
2172 return 0;
2173 }
2174
2175 if (!ptr) {
2176 /* Read frames from ring */
2177 ptr = tun_ring_recv(tfile, noblock, &err);
2178 if (!ptr)
2179 return err;
2180 }
2181
2182 if (tun_is_xdp_frame(ptr)) {
2183 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2184
2185 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2186 xdp_return_frame(xdpf);
2187 } else {
2188 struct sk_buff *skb = ptr;
2189
2190 ret = tun_put_user(tun, tfile, skb, to);
2191 if (unlikely(ret < 0))
2192 kfree_skb(skb);
2193 else
2194 consume_skb(skb);
2195 }
2196
2197 return ret;
2198}
2199
2200static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2201{
2202 struct file *file = iocb->ki_filp;
2203 struct tun_file *tfile = file->private_data;
2204 struct tun_struct *tun = tun_get(tfile);
2205 ssize_t len = iov_iter_count(to), ret;
2206
2207 if (!tun)
2208 return -EBADFD;
2209 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2210 ret = min_t(ssize_t, ret, len);
2211 if (ret > 0)
2212 iocb->ki_pos = ret;
2213 tun_put(tun);
2214 return ret;
2215}
2216
2217static void tun_prog_free(struct rcu_head *rcu)
2218{
2219 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2220
2221 bpf_prog_destroy(prog->prog);
2222 kfree(prog);
2223}
2224
2225static int __tun_set_ebpf(struct tun_struct *tun,
2226 struct tun_prog __rcu **prog_p,
2227 struct bpf_prog *prog)
2228{
2229 struct tun_prog *old, *new = NULL;
2230
2231 if (prog) {
2232 new = kmalloc(sizeof(*new), GFP_KERNEL);
2233 if (!new)
2234 return -ENOMEM;
2235 new->prog = prog;
2236 }
2237
2238 spin_lock_bh(&tun->lock);
2239 old = rcu_dereference_protected(*prog_p,
2240 lockdep_is_held(&tun->lock));
2241 rcu_assign_pointer(*prog_p, new);
2242 spin_unlock_bh(&tun->lock);
2243
2244 if (old)
2245 call_rcu(&old->rcu, tun_prog_free);
2246
2247 return 0;
2248}
2249
2250static void tun_free_netdev(struct net_device *dev)
2251{
2252 struct tun_struct *tun = netdev_priv(dev);
2253
2254 BUG_ON(!(list_empty(&tun->disabled)));
2255
2256 free_percpu(tun->pcpu_stats);
2257 /* We clear pcpu_stats so that tun_set_iff() can tell if
2258 * tun_free_netdev() has been called from register_netdevice().
2259 */
2260 tun->pcpu_stats = NULL;
2261
2262 tun_flow_uninit(tun);
2263 security_tun_dev_free_security(tun->security);
2264 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2265 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2266}
2267
2268static void tun_setup(struct net_device *dev)
2269{
2270 struct tun_struct *tun = netdev_priv(dev);
2271
2272 tun->owner = INVALID_UID;
2273 tun->group = INVALID_GID;
2274 tun_default_link_ksettings(dev, &tun->link_ksettings);
2275
2276 dev->ethtool_ops = &tun_ethtool_ops;
2277 dev->needs_free_netdev = true;
2278 dev->priv_destructor = tun_free_netdev;
2279 /* We prefer our own queue length */
2280 dev->tx_queue_len = TUN_READQ_SIZE;
2281}
2282
2283/* Trivial set of netlink ops to allow deleting tun or tap
2284 * device with netlink.
2285 */
2286static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2287 struct netlink_ext_ack *extack)
2288{
2289 NL_SET_ERR_MSG(extack,
2290 "tun/tap creation via rtnetlink is not supported.");
2291 return -EOPNOTSUPP;
2292}
2293
2294static size_t tun_get_size(const struct net_device *dev)
2295{
2296 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2297 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2298
2299 return nla_total_size(sizeof(uid_t)) + /* OWNER */
2300 nla_total_size(sizeof(gid_t)) + /* GROUP */
2301 nla_total_size(sizeof(u8)) + /* TYPE */
2302 nla_total_size(sizeof(u8)) + /* PI */
2303 nla_total_size(sizeof(u8)) + /* VNET_HDR */
2304 nla_total_size(sizeof(u8)) + /* PERSIST */
2305 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2306 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2307 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2308 0;
2309}
2310
2311static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2312{
2313 struct tun_struct *tun = netdev_priv(dev);
2314
2315 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2316 goto nla_put_failure;
2317 if (uid_valid(tun->owner) &&
2318 nla_put_u32(skb, IFLA_TUN_OWNER,
2319 from_kuid_munged(current_user_ns(), tun->owner)))
2320 goto nla_put_failure;
2321 if (gid_valid(tun->group) &&
2322 nla_put_u32(skb, IFLA_TUN_GROUP,
2323 from_kgid_munged(current_user_ns(), tun->group)))
2324 goto nla_put_failure;
2325 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2326 goto nla_put_failure;
2327 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2328 goto nla_put_failure;
2329 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2330 goto nla_put_failure;
2331 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2332 !!(tun->flags & IFF_MULTI_QUEUE)))
2333 goto nla_put_failure;
2334 if (tun->flags & IFF_MULTI_QUEUE) {
2335 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2336 goto nla_put_failure;
2337 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2338 tun->numdisabled))
2339 goto nla_put_failure;
2340 }
2341
2342 return 0;
2343
2344nla_put_failure:
2345 return -EMSGSIZE;
2346}
2347
2348static struct rtnl_link_ops tun_link_ops __read_mostly = {
2349 .kind = DRV_NAME,
2350 .priv_size = sizeof(struct tun_struct),
2351 .setup = tun_setup,
2352 .validate = tun_validate,
2353 .get_size = tun_get_size,
2354 .fill_info = tun_fill_info,
2355};
2356
2357static void tun_sock_write_space(struct sock *sk)
2358{
2359 struct tun_file *tfile;
2360 wait_queue_head_t *wqueue;
2361
2362 if (!sock_writeable(sk))
2363 return;
2364
2365 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2366 return;
2367
2368 wqueue = sk_sleep(sk);
2369 if (wqueue && waitqueue_active(wqueue))
2370 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2371 EPOLLWRNORM | EPOLLWRBAND);
2372
2373 tfile = container_of(sk, struct tun_file, sk);
2374 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2375}
2376
2377static void tun_put_page(struct tun_page *tpage)
2378{
2379 if (tpage->page)
2380 __page_frag_cache_drain(tpage->page, tpage->count);
2381}
2382
2383static int tun_xdp_one(struct tun_struct *tun,
2384 struct tun_file *tfile,
2385 struct xdp_buff *xdp, int *flush,
2386 struct tun_page *tpage)
2387{
2388 unsigned int datasize = xdp->data_end - xdp->data;
2389 struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2390 struct virtio_net_hdr *gso = &hdr->gso;
2391 struct tun_pcpu_stats *stats;
2392 struct bpf_prog *xdp_prog;
2393 struct sk_buff *skb = NULL;
2394 u32 rxhash = 0, act;
2395 int buflen = hdr->buflen;
2396 int err = 0;
2397 bool skb_xdp = false;
2398 struct page *page;
2399
2400 xdp_prog = rcu_dereference(tun->xdp_prog);
2401 if (xdp_prog) {
2402 if (gso->gso_type) {
2403 skb_xdp = true;
2404 goto build;
2405 }
2406 xdp_set_data_meta_invalid(xdp);
2407 xdp->rxq = &tfile->xdp_rxq;
2408 xdp->frame_sz = buflen;
2409
2410 act = bpf_prog_run_xdp(xdp_prog, xdp);
2411 err = tun_xdp_act(tun, xdp_prog, xdp, act);
2412 if (err < 0) {
2413 put_page(virt_to_head_page(xdp->data));
2414 return err;
2415 }
2416
2417 switch (err) {
2418 case XDP_REDIRECT:
2419 *flush = true;
2420 fallthrough;
2421 case XDP_TX:
2422 return 0;
2423 case XDP_PASS:
2424 break;
2425 default:
2426 page = virt_to_head_page(xdp->data);
2427 if (tpage->page == page) {
2428 ++tpage->count;
2429 } else {
2430 tun_put_page(tpage);
2431 tpage->page = page;
2432 tpage->count = 1;
2433 }
2434 return 0;
2435 }
2436 }
2437
2438build:
2439 skb = build_skb(xdp->data_hard_start, buflen);
2440 if (!skb) {
2441 err = -ENOMEM;
2442 goto out;
2443 }
2444
2445 skb_reserve(skb, xdp->data - xdp->data_hard_start);
2446 skb_put(skb, xdp->data_end - xdp->data);
2447
2448 if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2449 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
2450 kfree_skb(skb);
2451 err = -EINVAL;
2452 goto out;
2453 }
2454
2455 skb->protocol = eth_type_trans(skb, tun->dev);
2456 skb_reset_network_header(skb);
2457 skb_probe_transport_header(skb);
2458 skb_record_rx_queue(skb, tfile->queue_index);
2459
2460 if (skb_xdp) {
2461 err = do_xdp_generic(xdp_prog, skb);
2462 if (err != XDP_PASS)
2463 goto out;
2464 }
2465
2466 if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2467 !tfile->detached)
2468 rxhash = __skb_get_hash_symmetric(skb);
2469
2470 netif_receive_skb(skb);
2471
2472 /* No need for get_cpu_ptr() here since this function is
2473 * always called with bh disabled
2474 */
2475 stats = this_cpu_ptr(tun->pcpu_stats);
2476 u64_stats_update_begin(&stats->syncp);
2477 u64_stats_inc(&stats->rx_packets);
2478 u64_stats_add(&stats->rx_bytes, datasize);
2479 u64_stats_update_end(&stats->syncp);
2480
2481 if (rxhash)
2482 tun_flow_update(tun, rxhash, tfile);
2483
2484out:
2485 return err;
2486}
2487
2488static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2489{
2490 int ret, i;
2491 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2492 struct tun_struct *tun = tun_get(tfile);
2493 struct tun_msg_ctl *ctl = m->msg_control;
2494 struct xdp_buff *xdp;
2495
2496 if (!tun)
2497 return -EBADFD;
2498
2499 if (ctl && (ctl->type == TUN_MSG_PTR)) {
2500 struct tun_page tpage;
2501 int n = ctl->num;
2502 int flush = 0;
2503
2504 memset(&tpage, 0, sizeof(tpage));
2505
2506 local_bh_disable();
2507 rcu_read_lock();
2508
2509 for (i = 0; i < n; i++) {
2510 xdp = &((struct xdp_buff *)ctl->ptr)[i];
2511 tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2512 }
2513
2514 if (flush)
2515 xdp_do_flush();
2516
2517 rcu_read_unlock();
2518 local_bh_enable();
2519
2520 tun_put_page(&tpage);
2521
2522 ret = total_len;
2523 goto out;
2524 }
2525
2526 ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2527 m->msg_flags & MSG_DONTWAIT,
2528 m->msg_flags & MSG_MORE);
2529out:
2530 tun_put(tun);
2531 return ret;
2532}
2533
2534static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2535 int flags)
2536{
2537 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2538 struct tun_struct *tun = tun_get(tfile);
2539 void *ptr = m->msg_control;
2540 int ret;
2541
2542 if (!tun) {
2543 ret = -EBADFD;
2544 goto out_free;
2545 }
2546
2547 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2548 ret = -EINVAL;
2549 goto out_put_tun;
2550 }
2551 if (flags & MSG_ERRQUEUE) {
2552 ret = sock_recv_errqueue(sock->sk, m, total_len,
2553 SOL_PACKET, TUN_TX_TIMESTAMP);
2554 goto out;
2555 }
2556 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2557 if (ret > (ssize_t)total_len) {
2558 m->msg_flags |= MSG_TRUNC;
2559 ret = flags & MSG_TRUNC ? ret : total_len;
2560 }
2561out:
2562 tun_put(tun);
2563 return ret;
2564
2565out_put_tun:
2566 tun_put(tun);
2567out_free:
2568 tun_ptr_free(ptr);
2569 return ret;
2570}
2571
2572static int tun_ptr_peek_len(void *ptr)
2573{
2574 if (likely(ptr)) {
2575 if (tun_is_xdp_frame(ptr)) {
2576 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2577
2578 return xdpf->len;
2579 }
2580 return __skb_array_len_with_tag(ptr);
2581 } else {
2582 return 0;
2583 }
2584}
2585
2586static int tun_peek_len(struct socket *sock)
2587{
2588 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2589 struct tun_struct *tun;
2590 int ret = 0;
2591
2592 tun = tun_get(tfile);
2593 if (!tun)
2594 return 0;
2595
2596 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2597 tun_put(tun);
2598
2599 return ret;
2600}
2601
2602/* Ops structure to mimic raw sockets with tun */
2603static const struct proto_ops tun_socket_ops = {
2604 .peek_len = tun_peek_len,
2605 .sendmsg = tun_sendmsg,
2606 .recvmsg = tun_recvmsg,
2607};
2608
2609static struct proto tun_proto = {
2610 .name = "tun",
2611 .owner = THIS_MODULE,
2612 .obj_size = sizeof(struct tun_file),
2613};
2614
2615static int tun_flags(struct tun_struct *tun)
2616{
2617 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2618}
2619
2620static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2621 char *buf)
2622{
2623 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2624 return sprintf(buf, "0x%x\n", tun_flags(tun));
2625}
2626
2627static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2628 char *buf)
2629{
2630 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2631 return uid_valid(tun->owner)?
2632 sprintf(buf, "%u\n",
2633 from_kuid_munged(current_user_ns(), tun->owner)):
2634 sprintf(buf, "-1\n");
2635}
2636
2637static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2638 char *buf)
2639{
2640 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2641 return gid_valid(tun->group) ?
2642 sprintf(buf, "%u\n",
2643 from_kgid_munged(current_user_ns(), tun->group)):
2644 sprintf(buf, "-1\n");
2645}
2646
2647static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2648static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2649static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2650
2651static struct attribute *tun_dev_attrs[] = {
2652 &dev_attr_tun_flags.attr,
2653 &dev_attr_owner.attr,
2654 &dev_attr_group.attr,
2655 NULL
2656};
2657
2658static const struct attribute_group tun_attr_group = {
2659 .attrs = tun_dev_attrs
2660};
2661
2662static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2663{
2664 struct tun_struct *tun;
2665 struct tun_file *tfile = file->private_data;
2666 struct net_device *dev;
2667 int err;
2668
2669 if (tfile->detached)
2670 return -EINVAL;
2671
2672 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2673 if (!capable(CAP_NET_ADMIN))
2674 return -EPERM;
2675
2676 if (!(ifr->ifr_flags & IFF_NAPI) ||
2677 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2678 return -EINVAL;
2679 }
2680
2681 dev = __dev_get_by_name(net, ifr->ifr_name);
2682 if (dev) {
2683 if (ifr->ifr_flags & IFF_TUN_EXCL)
2684 return -EBUSY;
2685 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2686 tun = netdev_priv(dev);
2687 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2688 tun = netdev_priv(dev);
2689 else
2690 return -EINVAL;
2691
2692 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2693 !!(tun->flags & IFF_MULTI_QUEUE))
2694 return -EINVAL;
2695
2696 if (tun_not_capable(tun))
2697 return -EPERM;
2698 err = security_tun_dev_open(tun->security);
2699 if (err < 0)
2700 return err;
2701
2702 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2703 ifr->ifr_flags & IFF_NAPI,
2704 ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2705 if (err < 0)
2706 return err;
2707
2708 if (tun->flags & IFF_MULTI_QUEUE &&
2709 (tun->numqueues + tun->numdisabled > 1)) {
2710 /* One or more queue has already been attached, no need
2711 * to initialize the device again.
2712 */
2713 netdev_state_change(dev);
2714 return 0;
2715 }
2716
2717 tun->flags = (tun->flags & ~TUN_FEATURES) |
2718 (ifr->ifr_flags & TUN_FEATURES);
2719
2720 netdev_state_change(dev);
2721 } else {
2722 char *name;
2723 unsigned long flags = 0;
2724 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2725 MAX_TAP_QUEUES : 1;
2726
2727 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2728 return -EPERM;
2729 err = security_tun_dev_create();
2730 if (err < 0)
2731 return err;
2732
2733 /* Set dev type */
2734 if (ifr->ifr_flags & IFF_TUN) {
2735 /* TUN device */
2736 flags |= IFF_TUN;
2737 name = "tun%d";
2738 } else if (ifr->ifr_flags & IFF_TAP) {
2739 /* TAP device */
2740 flags |= IFF_TAP;
2741 name = "tap%d";
2742 } else
2743 return -EINVAL;
2744
2745 if (*ifr->ifr_name)
2746 name = ifr->ifr_name;
2747
2748 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2749 NET_NAME_UNKNOWN, tun_setup, queues,
2750 queues);
2751
2752 if (!dev)
2753 return -ENOMEM;
2754
2755 dev_net_set(dev, net);
2756 dev->rtnl_link_ops = &tun_link_ops;
2757 dev->ifindex = tfile->ifindex;
2758 dev->sysfs_groups[0] = &tun_attr_group;
2759
2760 tun = netdev_priv(dev);
2761 tun->dev = dev;
2762 tun->flags = flags;
2763 tun->txflt.count = 0;
2764 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2765
2766 tun->align = NET_SKB_PAD;
2767 tun->filter_attached = false;
2768 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2769 tun->rx_batched = 0;
2770 RCU_INIT_POINTER(tun->steering_prog, NULL);
2771
2772 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2773 if (!tun->pcpu_stats) {
2774 err = -ENOMEM;
2775 goto err_free_dev;
2776 }
2777
2778 spin_lock_init(&tun->lock);
2779
2780 err = security_tun_dev_alloc_security(&tun->security);
2781 if (err < 0)
2782 goto err_free_stat;
2783
2784 tun_net_init(dev);
2785 tun_flow_init(tun);
2786
2787 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2788 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2789 NETIF_F_HW_VLAN_STAG_TX;
2790 dev->features = dev->hw_features | NETIF_F_LLTX;
2791 dev->vlan_features = dev->features &
2792 ~(NETIF_F_HW_VLAN_CTAG_TX |
2793 NETIF_F_HW_VLAN_STAG_TX);
2794
2795 tun->flags = (tun->flags & ~TUN_FEATURES) |
2796 (ifr->ifr_flags & TUN_FEATURES);
2797
2798 INIT_LIST_HEAD(&tun->disabled);
2799 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI,
2800 ifr->ifr_flags & IFF_NAPI_FRAGS, false);
2801 if (err < 0)
2802 goto err_free_flow;
2803
2804 err = register_netdevice(tun->dev);
2805 if (err < 0)
2806 goto err_detach;
2807 /* free_netdev() won't check refcnt, to aovid race
2808 * with dev_put() we need publish tun after registration.
2809 */
2810 rcu_assign_pointer(tfile->tun, tun);
2811 }
2812
2813 netif_carrier_on(tun->dev);
2814
2815 /* Make sure persistent devices do not get stuck in
2816 * xoff state.
2817 */
2818 if (netif_running(tun->dev))
2819 netif_tx_wake_all_queues(tun->dev);
2820
2821 strcpy(ifr->ifr_name, tun->dev->name);
2822 return 0;
2823
2824err_detach:
2825 tun_detach_all(dev);
2826 /* We are here because register_netdevice() has failed.
2827 * If register_netdevice() already called tun_free_netdev()
2828 * while dealing with the error, tun->pcpu_stats has been cleared.
2829 */
2830 if (!tun->pcpu_stats)
2831 goto err_free_dev;
2832
2833err_free_flow:
2834 tun_flow_uninit(tun);
2835 security_tun_dev_free_security(tun->security);
2836err_free_stat:
2837 free_percpu(tun->pcpu_stats);
2838err_free_dev:
2839 free_netdev(dev);
2840 return err;
2841}
2842
2843static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2844{
2845 strcpy(ifr->ifr_name, tun->dev->name);
2846
2847 ifr->ifr_flags = tun_flags(tun);
2848
2849}
2850
2851/* This is like a cut-down ethtool ops, except done via tun fd so no
2852 * privs required. */
2853static int set_offload(struct tun_struct *tun, unsigned long arg)
2854{
2855 netdev_features_t features = 0;
2856
2857 if (arg & TUN_F_CSUM) {
2858 features |= NETIF_F_HW_CSUM;
2859 arg &= ~TUN_F_CSUM;
2860
2861 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2862 if (arg & TUN_F_TSO_ECN) {
2863 features |= NETIF_F_TSO_ECN;
2864 arg &= ~TUN_F_TSO_ECN;
2865 }
2866 if (arg & TUN_F_TSO4)
2867 features |= NETIF_F_TSO;
2868 if (arg & TUN_F_TSO6)
2869 features |= NETIF_F_TSO6;
2870 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2871 }
2872
2873 arg &= ~TUN_F_UFO;
2874 }
2875
2876 /* This gives the user a way to test for new features in future by
2877 * trying to set them. */
2878 if (arg)
2879 return -EINVAL;
2880
2881 tun->set_features = features;
2882 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2883 tun->dev->wanted_features |= features;
2884 netdev_update_features(tun->dev);
2885
2886 return 0;
2887}
2888
2889static void tun_detach_filter(struct tun_struct *tun, int n)
2890{
2891 int i;
2892 struct tun_file *tfile;
2893
2894 for (i = 0; i < n; i++) {
2895 tfile = rtnl_dereference(tun->tfiles[i]);
2896 lock_sock(tfile->socket.sk);
2897 sk_detach_filter(tfile->socket.sk);
2898 release_sock(tfile->socket.sk);
2899 }
2900
2901 tun->filter_attached = false;
2902}
2903
2904static int tun_attach_filter(struct tun_struct *tun)
2905{
2906 int i, ret = 0;
2907 struct tun_file *tfile;
2908
2909 for (i = 0; i < tun->numqueues; i++) {
2910 tfile = rtnl_dereference(tun->tfiles[i]);
2911 lock_sock(tfile->socket.sk);
2912 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2913 release_sock(tfile->socket.sk);
2914 if (ret) {
2915 tun_detach_filter(tun, i);
2916 return ret;
2917 }
2918 }
2919
2920 tun->filter_attached = true;
2921 return ret;
2922}
2923
2924static void tun_set_sndbuf(struct tun_struct *tun)
2925{
2926 struct tun_file *tfile;
2927 int i;
2928
2929 for (i = 0; i < tun->numqueues; i++) {
2930 tfile = rtnl_dereference(tun->tfiles[i]);
2931 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2932 }
2933}
2934
2935static int tun_set_queue(struct file *file, struct ifreq *ifr)
2936{
2937 struct tun_file *tfile = file->private_data;
2938 struct tun_struct *tun;
2939 int ret = 0;
2940
2941 rtnl_lock();
2942
2943 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2944 tun = tfile->detached;
2945 if (!tun) {
2946 ret = -EINVAL;
2947 goto unlock;
2948 }
2949 ret = security_tun_dev_attach_queue(tun->security);
2950 if (ret < 0)
2951 goto unlock;
2952 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2953 tun->flags & IFF_NAPI_FRAGS, true);
2954 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2955 tun = rtnl_dereference(tfile->tun);
2956 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2957 ret = -EINVAL;
2958 else
2959 __tun_detach(tfile, false);
2960 } else
2961 ret = -EINVAL;
2962
2963 if (ret >= 0)
2964 netdev_state_change(tun->dev);
2965
2966unlock:
2967 rtnl_unlock();
2968 return ret;
2969}
2970
2971static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog __rcu **prog_p,
2972 void __user *data)
2973{
2974 struct bpf_prog *prog;
2975 int fd;
2976
2977 if (copy_from_user(&fd, data, sizeof(fd)))
2978 return -EFAULT;
2979
2980 if (fd == -1) {
2981 prog = NULL;
2982 } else {
2983 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
2984 if (IS_ERR(prog))
2985 return PTR_ERR(prog);
2986 }
2987
2988 return __tun_set_ebpf(tun, prog_p, prog);
2989}
2990
2991static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2992 unsigned long arg, int ifreq_len)
2993{
2994 struct tun_file *tfile = file->private_data;
2995 struct net *net = sock_net(&tfile->sk);
2996 struct tun_struct *tun;
2997 void __user* argp = (void __user*)arg;
2998 unsigned int ifindex, carrier;
2999 struct ifreq ifr;
3000 kuid_t owner;
3001 kgid_t group;
3002 int sndbuf;
3003 int vnet_hdr_sz;
3004 int le;
3005 int ret;
3006 bool do_notify = false;
3007
3008 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3009 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3010 if (copy_from_user(&ifr, argp, ifreq_len))
3011 return -EFAULT;
3012 } else {
3013 memset(&ifr, 0, sizeof(ifr));
3014 }
3015 if (cmd == TUNGETFEATURES) {
3016 /* Currently this just means: "what IFF flags are valid?".
3017 * This is needed because we never checked for invalid flags on
3018 * TUNSETIFF.
3019 */
3020 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
3021 (unsigned int __user*)argp);
3022 } else if (cmd == TUNSETQUEUE) {
3023 return tun_set_queue(file, &ifr);
3024 } else if (cmd == SIOCGSKNS) {
3025 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3026 return -EPERM;
3027 return open_related_ns(&net->ns, get_net_ns);
3028 }
3029
3030 ret = 0;
3031 rtnl_lock();
3032
3033 tun = tun_get(tfile);
3034 if (cmd == TUNSETIFF) {
3035 ret = -EEXIST;
3036 if (tun)
3037 goto unlock;
3038
3039 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3040
3041 ret = tun_set_iff(net, file, &ifr);
3042
3043 if (ret)
3044 goto unlock;
3045
3046 if (copy_to_user(argp, &ifr, ifreq_len))
3047 ret = -EFAULT;
3048 goto unlock;
3049 }
3050 if (cmd == TUNSETIFINDEX) {
3051 ret = -EPERM;
3052 if (tun)
3053 goto unlock;
3054
3055 ret = -EFAULT;
3056 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3057 goto unlock;
3058
3059 ret = 0;
3060 tfile->ifindex = ifindex;
3061 goto unlock;
3062 }
3063
3064 ret = -EBADFD;
3065 if (!tun)
3066 goto unlock;
3067
3068 netif_info(tun, drv, tun->dev, "tun_chr_ioctl cmd %u\n", cmd);
3069
3070 net = dev_net(tun->dev);
3071 ret = 0;
3072 switch (cmd) {
3073 case TUNGETIFF:
3074 tun_get_iff(tun, &ifr);
3075
3076 if (tfile->detached)
3077 ifr.ifr_flags |= IFF_DETACH_QUEUE;
3078 if (!tfile->socket.sk->sk_filter)
3079 ifr.ifr_flags |= IFF_NOFILTER;
3080
3081 if (copy_to_user(argp, &ifr, ifreq_len))
3082 ret = -EFAULT;
3083 break;
3084
3085 case TUNSETNOCSUM:
3086 /* Disable/Enable checksum */
3087
3088 /* [unimplemented] */
3089 netif_info(tun, drv, tun->dev, "ignored: set checksum %s\n",
3090 arg ? "disabled" : "enabled");
3091 break;
3092
3093 case TUNSETPERSIST:
3094 /* Disable/Enable persist mode. Keep an extra reference to the
3095 * module to prevent the module being unprobed.
3096 */
3097 if (arg && !(tun->flags & IFF_PERSIST)) {
3098 tun->flags |= IFF_PERSIST;
3099 __module_get(THIS_MODULE);
3100 do_notify = true;
3101 }
3102 if (!arg && (tun->flags & IFF_PERSIST)) {
3103 tun->flags &= ~IFF_PERSIST;
3104 module_put(THIS_MODULE);
3105 do_notify = true;
3106 }
3107
3108 netif_info(tun, drv, tun->dev, "persist %s\n",
3109 arg ? "enabled" : "disabled");
3110 break;
3111
3112 case TUNSETOWNER:
3113 /* Set owner of the device */
3114 owner = make_kuid(current_user_ns(), arg);
3115 if (!uid_valid(owner)) {
3116 ret = -EINVAL;
3117 break;
3118 }
3119 tun->owner = owner;
3120 do_notify = true;
3121 netif_info(tun, drv, tun->dev, "owner set to %u\n",
3122 from_kuid(&init_user_ns, tun->owner));
3123 break;
3124
3125 case TUNSETGROUP:
3126 /* Set group of the device */
3127 group = make_kgid(current_user_ns(), arg);
3128 if (!gid_valid(group)) {
3129 ret = -EINVAL;
3130 break;
3131 }
3132 tun->group = group;
3133 do_notify = true;
3134 netif_info(tun, drv, tun->dev, "group set to %u\n",
3135 from_kgid(&init_user_ns, tun->group));
3136 break;
3137
3138 case TUNSETLINK:
3139 /* Only allow setting the type when the interface is down */
3140 if (tun->dev->flags & IFF_UP) {
3141 netif_info(tun, drv, tun->dev,
3142 "Linktype set failed because interface is up\n");
3143 ret = -EBUSY;
3144 } else {
3145 tun->dev->type = (int) arg;
3146 netif_info(tun, drv, tun->dev, "linktype set to %d\n",
3147 tun->dev->type);
3148 ret = 0;
3149 }
3150 break;
3151
3152 case TUNSETDEBUG:
3153 tun->msg_enable = (u32)arg;
3154 break;
3155
3156 case TUNSETOFFLOAD:
3157 ret = set_offload(tun, arg);
3158 break;
3159
3160 case TUNSETTXFILTER:
3161 /* Can be set only for TAPs */
3162 ret = -EINVAL;
3163 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3164 break;
3165 ret = update_filter(&tun->txflt, (void __user *)arg);
3166 break;
3167
3168 case SIOCGIFHWADDR:
3169 /* Get hw address */
3170 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3171 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3172 if (copy_to_user(argp, &ifr, ifreq_len))
3173 ret = -EFAULT;
3174 break;
3175
3176 case SIOCSIFHWADDR:
3177 /* Set hw address */
3178 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr, NULL);
3179 break;
3180
3181 case TUNGETSNDBUF:
3182 sndbuf = tfile->socket.sk->sk_sndbuf;
3183 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3184 ret = -EFAULT;
3185 break;
3186
3187 case TUNSETSNDBUF:
3188 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3189 ret = -EFAULT;
3190 break;
3191 }
3192 if (sndbuf <= 0) {
3193 ret = -EINVAL;
3194 break;
3195 }
3196
3197 tun->sndbuf = sndbuf;
3198 tun_set_sndbuf(tun);
3199 break;
3200
3201 case TUNGETVNETHDRSZ:
3202 vnet_hdr_sz = tun->vnet_hdr_sz;
3203 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3204 ret = -EFAULT;
3205 break;
3206
3207 case TUNSETVNETHDRSZ:
3208 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3209 ret = -EFAULT;
3210 break;
3211 }
3212 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3213 ret = -EINVAL;
3214 break;
3215 }
3216
3217 tun->vnet_hdr_sz = vnet_hdr_sz;
3218 break;
3219
3220 case TUNGETVNETLE:
3221 le = !!(tun->flags & TUN_VNET_LE);
3222 if (put_user(le, (int __user *)argp))
3223 ret = -EFAULT;
3224 break;
3225
3226 case TUNSETVNETLE:
3227 if (get_user(le, (int __user *)argp)) {
3228 ret = -EFAULT;
3229 break;
3230 }
3231 if (le)
3232 tun->flags |= TUN_VNET_LE;
3233 else
3234 tun->flags &= ~TUN_VNET_LE;
3235 break;
3236
3237 case TUNGETVNETBE:
3238 ret = tun_get_vnet_be(tun, argp);
3239 break;
3240
3241 case TUNSETVNETBE:
3242 ret = tun_set_vnet_be(tun, argp);
3243 break;
3244
3245 case TUNATTACHFILTER:
3246 /* Can be set only for TAPs */
3247 ret = -EINVAL;
3248 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3249 break;
3250 ret = -EFAULT;
3251 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3252 break;
3253
3254 ret = tun_attach_filter(tun);
3255 break;
3256
3257 case TUNDETACHFILTER:
3258 /* Can be set only for TAPs */
3259 ret = -EINVAL;
3260 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3261 break;
3262 ret = 0;
3263 tun_detach_filter(tun, tun->numqueues);
3264 break;
3265
3266 case TUNGETFILTER:
3267 ret = -EINVAL;
3268 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3269 break;
3270 ret = -EFAULT;
3271 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3272 break;
3273 ret = 0;
3274 break;
3275
3276 case TUNSETSTEERINGEBPF:
3277 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3278 break;
3279
3280 case TUNSETFILTEREBPF:
3281 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3282 break;
3283
3284 case TUNSETCARRIER:
3285 ret = -EFAULT;
3286 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3287 goto unlock;
3288
3289 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3290 break;
3291
3292 case TUNGETDEVNETNS:
3293 ret = -EPERM;
3294 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3295 goto unlock;
3296 ret = open_related_ns(&net->ns, get_net_ns);
3297 break;
3298
3299 default:
3300 ret = -EINVAL;
3301 break;
3302 }
3303
3304 if (do_notify)
3305 netdev_state_change(tun->dev);
3306
3307unlock:
3308 rtnl_unlock();
3309 if (tun)
3310 tun_put(tun);
3311 return ret;
3312}
3313
3314static long tun_chr_ioctl(struct file *file,
3315 unsigned int cmd, unsigned long arg)
3316{
3317 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3318}
3319
3320#ifdef CONFIG_COMPAT
3321static long tun_chr_compat_ioctl(struct file *file,
3322 unsigned int cmd, unsigned long arg)
3323{
3324 switch (cmd) {
3325 case TUNSETIFF:
3326 case TUNGETIFF:
3327 case TUNSETTXFILTER:
3328 case TUNGETSNDBUF:
3329 case TUNSETSNDBUF:
3330 case SIOCGIFHWADDR:
3331 case SIOCSIFHWADDR:
3332 arg = (unsigned long)compat_ptr(arg);
3333 break;
3334 default:
3335 arg = (compat_ulong_t)arg;
3336 break;
3337 }
3338
3339 /*
3340 * compat_ifreq is shorter than ifreq, so we must not access beyond
3341 * the end of that structure. All fields that are used in this
3342 * driver are compatible though, we don't need to convert the
3343 * contents.
3344 */
3345 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3346}
3347#endif /* CONFIG_COMPAT */
3348
3349static int tun_chr_fasync(int fd, struct file *file, int on)
3350{
3351 struct tun_file *tfile = file->private_data;
3352 int ret;
3353
3354 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3355 goto out;
3356
3357 if (on) {
3358 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3359 tfile->flags |= TUN_FASYNC;
3360 } else
3361 tfile->flags &= ~TUN_FASYNC;
3362 ret = 0;
3363out:
3364 return ret;
3365}
3366
3367static int tun_chr_open(struct inode *inode, struct file * file)
3368{
3369 struct net *net = current->nsproxy->net_ns;
3370 struct tun_file *tfile;
3371
3372 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3373 &tun_proto, 0);
3374 if (!tfile)
3375 return -ENOMEM;
3376 if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3377 sk_free(&tfile->sk);
3378 return -ENOMEM;
3379 }
3380
3381 mutex_init(&tfile->napi_mutex);
3382 RCU_INIT_POINTER(tfile->tun, NULL);
3383 tfile->flags = 0;
3384 tfile->ifindex = 0;
3385
3386 init_waitqueue_head(&tfile->socket.wq.wait);
3387
3388 tfile->socket.file = file;
3389 tfile->socket.ops = &tun_socket_ops;
3390
3391 sock_init_data(&tfile->socket, &tfile->sk);
3392
3393 tfile->sk.sk_write_space = tun_sock_write_space;
3394 tfile->sk.sk_sndbuf = INT_MAX;
3395
3396 file->private_data = tfile;
3397 INIT_LIST_HEAD(&tfile->next);
3398
3399 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3400
3401 return 0;
3402}
3403
3404static int tun_chr_close(struct inode *inode, struct file *file)
3405{
3406 struct tun_file *tfile = file->private_data;
3407
3408 tun_detach(tfile, true);
3409
3410 return 0;
3411}
3412
3413#ifdef CONFIG_PROC_FS
3414static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3415{
3416 struct tun_file *tfile = file->private_data;
3417 struct tun_struct *tun;
3418 struct ifreq ifr;
3419
3420 memset(&ifr, 0, sizeof(ifr));
3421
3422 rtnl_lock();
3423 tun = tun_get(tfile);
3424 if (tun)
3425 tun_get_iff(tun, &ifr);
3426 rtnl_unlock();
3427
3428 if (tun)
3429 tun_put(tun);
3430
3431 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3432}
3433#endif
3434
3435static const struct file_operations tun_fops = {
3436 .owner = THIS_MODULE,
3437 .llseek = no_llseek,
3438 .read_iter = tun_chr_read_iter,
3439 .write_iter = tun_chr_write_iter,
3440 .poll = tun_chr_poll,
3441 .unlocked_ioctl = tun_chr_ioctl,
3442#ifdef CONFIG_COMPAT
3443 .compat_ioctl = tun_chr_compat_ioctl,
3444#endif
3445 .open = tun_chr_open,
3446 .release = tun_chr_close,
3447 .fasync = tun_chr_fasync,
3448#ifdef CONFIG_PROC_FS
3449 .show_fdinfo = tun_chr_show_fdinfo,
3450#endif
3451};
3452
3453static struct miscdevice tun_miscdev = {
3454 .minor = TUN_MINOR,
3455 .name = "tun",
3456 .nodename = "net/tun",
3457 .fops = &tun_fops,
3458};
3459
3460/* ethtool interface */
3461
3462static void tun_default_link_ksettings(struct net_device *dev,
3463 struct ethtool_link_ksettings *cmd)
3464{
3465 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3466 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3467 cmd->base.speed = SPEED_10;
3468 cmd->base.duplex = DUPLEX_FULL;
3469 cmd->base.port = PORT_TP;
3470 cmd->base.phy_address = 0;
3471 cmd->base.autoneg = AUTONEG_DISABLE;
3472}
3473
3474static int tun_get_link_ksettings(struct net_device *dev,
3475 struct ethtool_link_ksettings *cmd)
3476{
3477 struct tun_struct *tun = netdev_priv(dev);
3478
3479 memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3480 return 0;
3481}
3482
3483static int tun_set_link_ksettings(struct net_device *dev,
3484 const struct ethtool_link_ksettings *cmd)
3485{
3486 struct tun_struct *tun = netdev_priv(dev);
3487
3488 memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3489 return 0;
3490}
3491
3492static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3493{
3494 struct tun_struct *tun = netdev_priv(dev);
3495
3496 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3497 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3498
3499 switch (tun->flags & TUN_TYPE_MASK) {
3500 case IFF_TUN:
3501 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3502 break;
3503 case IFF_TAP:
3504 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3505 break;
3506 }
3507}
3508
3509static u32 tun_get_msglevel(struct net_device *dev)
3510{
3511 struct tun_struct *tun = netdev_priv(dev);
3512
3513 return tun->msg_enable;
3514}
3515
3516static void tun_set_msglevel(struct net_device *dev, u32 value)
3517{
3518 struct tun_struct *tun = netdev_priv(dev);
3519
3520 tun->msg_enable = value;
3521}
3522
3523static int tun_get_coalesce(struct net_device *dev,
3524 struct ethtool_coalesce *ec)
3525{
3526 struct tun_struct *tun = netdev_priv(dev);
3527
3528 ec->rx_max_coalesced_frames = tun->rx_batched;
3529
3530 return 0;
3531}
3532
3533static int tun_set_coalesce(struct net_device *dev,
3534 struct ethtool_coalesce *ec)
3535{
3536 struct tun_struct *tun = netdev_priv(dev);
3537
3538 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3539 tun->rx_batched = NAPI_POLL_WEIGHT;
3540 else
3541 tun->rx_batched = ec->rx_max_coalesced_frames;
3542
3543 return 0;
3544}
3545
3546static const struct ethtool_ops tun_ethtool_ops = {
3547 .supported_coalesce_params = ETHTOOL_COALESCE_RX_MAX_FRAMES,
3548 .get_drvinfo = tun_get_drvinfo,
3549 .get_msglevel = tun_get_msglevel,
3550 .set_msglevel = tun_set_msglevel,
3551 .get_link = ethtool_op_get_link,
3552 .get_ts_info = ethtool_op_get_ts_info,
3553 .get_coalesce = tun_get_coalesce,
3554 .set_coalesce = tun_set_coalesce,
3555 .get_link_ksettings = tun_get_link_ksettings,
3556 .set_link_ksettings = tun_set_link_ksettings,
3557};
3558
3559static int tun_queue_resize(struct tun_struct *tun)
3560{
3561 struct net_device *dev = tun->dev;
3562 struct tun_file *tfile;
3563 struct ptr_ring **rings;
3564 int n = tun->numqueues + tun->numdisabled;
3565 int ret, i;
3566
3567 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3568 if (!rings)
3569 return -ENOMEM;
3570
3571 for (i = 0; i < tun->numqueues; i++) {
3572 tfile = rtnl_dereference(tun->tfiles[i]);
3573 rings[i] = &tfile->tx_ring;
3574 }
3575 list_for_each_entry(tfile, &tun->disabled, next)
3576 rings[i++] = &tfile->tx_ring;
3577
3578 ret = ptr_ring_resize_multiple(rings, n,
3579 dev->tx_queue_len, GFP_KERNEL,
3580 tun_ptr_free);
3581
3582 kfree(rings);
3583 return ret;
3584}
3585
3586static int tun_device_event(struct notifier_block *unused,
3587 unsigned long event, void *ptr)
3588{
3589 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3590 struct tun_struct *tun = netdev_priv(dev);
3591 int i;
3592
3593 if (dev->rtnl_link_ops != &tun_link_ops)
3594 return NOTIFY_DONE;
3595
3596 switch (event) {
3597 case NETDEV_CHANGE_TX_QUEUE_LEN:
3598 if (tun_queue_resize(tun))
3599 return NOTIFY_BAD;
3600 break;
3601 case NETDEV_UP:
3602 for (i = 0; i < tun->numqueues; i++) {
3603 struct tun_file *tfile;
3604
3605 tfile = rtnl_dereference(tun->tfiles[i]);
3606 tfile->socket.sk->sk_write_space(tfile->socket.sk);
3607 }
3608 break;
3609 default:
3610 break;
3611 }
3612
3613 return NOTIFY_DONE;
3614}
3615
3616static struct notifier_block tun_notifier_block __read_mostly = {
3617 .notifier_call = tun_device_event,
3618};
3619
3620static int __init tun_init(void)
3621{
3622 int ret = 0;
3623
3624 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3625
3626 ret = rtnl_link_register(&tun_link_ops);
3627 if (ret) {
3628 pr_err("Can't register link_ops\n");
3629 goto err_linkops;
3630 }
3631
3632 ret = misc_register(&tun_miscdev);
3633 if (ret) {
3634 pr_err("Can't register misc device %d\n", TUN_MINOR);
3635 goto err_misc;
3636 }
3637
3638 ret = register_netdevice_notifier(&tun_notifier_block);
3639 if (ret) {
3640 pr_err("Can't register netdevice notifier\n");
3641 goto err_notifier;
3642 }
3643
3644 return 0;
3645
3646err_notifier:
3647 misc_deregister(&tun_miscdev);
3648err_misc:
3649 rtnl_link_unregister(&tun_link_ops);
3650err_linkops:
3651 return ret;
3652}
3653
3654static void tun_cleanup(void)
3655{
3656 misc_deregister(&tun_miscdev);
3657 rtnl_link_unregister(&tun_link_ops);
3658 unregister_netdevice_notifier(&tun_notifier_block);
3659}
3660
3661/* Get an underlying socket object from tun file. Returns error unless file is
3662 * attached to a device. The returned object works like a packet socket, it
3663 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3664 * holding a reference to the file for as long as the socket is in use. */
3665struct socket *tun_get_socket(struct file *file)
3666{
3667 struct tun_file *tfile;
3668 if (file->f_op != &tun_fops)
3669 return ERR_PTR(-EINVAL);
3670 tfile = file->private_data;
3671 if (!tfile)
3672 return ERR_PTR(-EBADFD);
3673 return &tfile->socket;
3674}
3675EXPORT_SYMBOL_GPL(tun_get_socket);
3676
3677struct ptr_ring *tun_get_tx_ring(struct file *file)
3678{
3679 struct tun_file *tfile;
3680
3681 if (file->f_op != &tun_fops)
3682 return ERR_PTR(-EINVAL);
3683 tfile = file->private_data;
3684 if (!tfile)
3685 return ERR_PTR(-EBADFD);
3686 return &tfile->tx_ring;
3687}
3688EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3689
3690module_init(tun_init);
3691module_exit(tun_cleanup);
3692MODULE_DESCRIPTION(DRV_DESCRIPTION);
3693MODULE_AUTHOR(DRV_COPYRIGHT);
3694MODULE_LICENSE("GPL");
3695MODULE_ALIAS_MISCDEV(TUN_MINOR);
3696MODULE_ALIAS("devname:net/tun");