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1/*
2 * TUN - Universal TUN/TAP device driver.
3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
16 */
17
18/*
19 * Changes:
20 *
21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
22 * Add TUNSETLINK ioctl to set the link encapsulation
23 *
24 * Mark Smith <markzzzsmith@yahoo.com.au>
25 * Use random_ether_addr() for tap MAC address.
26 *
27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
28 * Fixes in packet dropping, queue length setting and queue wakeup.
29 * Increased default tx queue length.
30 * Added ethtool API.
31 * Minor cleanups
32 *
33 * Daniel Podlejski <underley@underley.eu.org>
34 * Modifications for 2.3.99-pre5 kernel.
35 */
36
37#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
38
39#define DRV_NAME "tun"
40#define DRV_VERSION "1.6"
41#define DRV_DESCRIPTION "Universal TUN/TAP device driver"
42#define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
43
44#include <linux/module.h>
45#include <linux/errno.h>
46#include <linux/kernel.h>
47#include <linux/major.h>
48#include <linux/slab.h>
49#include <linux/poll.h>
50#include <linux/fcntl.h>
51#include <linux/init.h>
52#include <linux/skbuff.h>
53#include <linux/netdevice.h>
54#include <linux/etherdevice.h>
55#include <linux/miscdevice.h>
56#include <linux/ethtool.h>
57#include <linux/rtnetlink.h>
58#include <linux/compat.h>
59#include <linux/if.h>
60#include <linux/if_arp.h>
61#include <linux/if_ether.h>
62#include <linux/if_tun.h>
63#include <linux/crc32.h>
64#include <linux/nsproxy.h>
65#include <linux/virtio_net.h>
66#include <linux/rcupdate.h>
67#include <net/net_namespace.h>
68#include <net/netns/generic.h>
69#include <net/rtnetlink.h>
70#include <net/sock.h>
71
72#include <asm/system.h>
73#include <asm/uaccess.h>
74
75/* Uncomment to enable debugging */
76/* #define TUN_DEBUG 1 */
77
78#ifdef TUN_DEBUG
79static int debug;
80
81#define tun_debug(level, tun, fmt, args...) \
82do { \
83 if (tun->debug) \
84 netdev_printk(level, tun->dev, fmt, ##args); \
85} while (0)
86#define DBG1(level, fmt, args...) \
87do { \
88 if (debug == 2) \
89 printk(level fmt, ##args); \
90} while (0)
91#else
92#define tun_debug(level, tun, fmt, args...) \
93do { \
94 if (0) \
95 netdev_printk(level, tun->dev, fmt, ##args); \
96} while (0)
97#define DBG1(level, fmt, args...) \
98do { \
99 if (0) \
100 printk(level fmt, ##args); \
101} while (0)
102#endif
103
104#define FLT_EXACT_COUNT 8
105struct tap_filter {
106 unsigned int count; /* Number of addrs. Zero means disabled */
107 u32 mask[2]; /* Mask of the hashed addrs */
108 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
109};
110
111struct tun_file {
112 atomic_t count;
113 struct tun_struct *tun;
114 struct net *net;
115};
116
117struct tun_sock;
118
119struct tun_struct {
120 struct tun_file *tfile;
121 unsigned int flags;
122 uid_t owner;
123 gid_t group;
124
125 struct net_device *dev;
126 u32 set_features;
127#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
128 NETIF_F_TSO6|NETIF_F_UFO)
129 struct fasync_struct *fasync;
130
131 struct tap_filter txflt;
132 struct socket socket;
133 struct socket_wq wq;
134
135 int vnet_hdr_sz;
136
137#ifdef TUN_DEBUG
138 int debug;
139#endif
140};
141
142struct tun_sock {
143 struct sock sk;
144 struct tun_struct *tun;
145};
146
147static inline struct tun_sock *tun_sk(struct sock *sk)
148{
149 return container_of(sk, struct tun_sock, sk);
150}
151
152static int tun_attach(struct tun_struct *tun, struct file *file)
153{
154 struct tun_file *tfile = file->private_data;
155 int err;
156
157 ASSERT_RTNL();
158
159 netif_tx_lock_bh(tun->dev);
160
161 err = -EINVAL;
162 if (tfile->tun)
163 goto out;
164
165 err = -EBUSY;
166 if (tun->tfile)
167 goto out;
168
169 err = 0;
170 tfile->tun = tun;
171 tun->tfile = tfile;
172 tun->socket.file = file;
173 netif_carrier_on(tun->dev);
174 dev_hold(tun->dev);
175 sock_hold(tun->socket.sk);
176 atomic_inc(&tfile->count);
177
178out:
179 netif_tx_unlock_bh(tun->dev);
180 return err;
181}
182
183static void __tun_detach(struct tun_struct *tun)
184{
185 /* Detach from net device */
186 netif_tx_lock_bh(tun->dev);
187 netif_carrier_off(tun->dev);
188 tun->tfile = NULL;
189 tun->socket.file = NULL;
190 netif_tx_unlock_bh(tun->dev);
191
192 /* Drop read queue */
193 skb_queue_purge(&tun->socket.sk->sk_receive_queue);
194
195 /* Drop the extra count on the net device */
196 dev_put(tun->dev);
197}
198
199static void tun_detach(struct tun_struct *tun)
200{
201 rtnl_lock();
202 __tun_detach(tun);
203 rtnl_unlock();
204}
205
206static struct tun_struct *__tun_get(struct tun_file *tfile)
207{
208 struct tun_struct *tun = NULL;
209
210 if (atomic_inc_not_zero(&tfile->count))
211 tun = tfile->tun;
212
213 return tun;
214}
215
216static struct tun_struct *tun_get(struct file *file)
217{
218 return __tun_get(file->private_data);
219}
220
221static void tun_put(struct tun_struct *tun)
222{
223 struct tun_file *tfile = tun->tfile;
224
225 if (atomic_dec_and_test(&tfile->count))
226 tun_detach(tfile->tun);
227}
228
229/* TAP filtering */
230static void addr_hash_set(u32 *mask, const u8 *addr)
231{
232 int n = ether_crc(ETH_ALEN, addr) >> 26;
233 mask[n >> 5] |= (1 << (n & 31));
234}
235
236static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
237{
238 int n = ether_crc(ETH_ALEN, addr) >> 26;
239 return mask[n >> 5] & (1 << (n & 31));
240}
241
242static int update_filter(struct tap_filter *filter, void __user *arg)
243{
244 struct { u8 u[ETH_ALEN]; } *addr;
245 struct tun_filter uf;
246 int err, alen, n, nexact;
247
248 if (copy_from_user(&uf, arg, sizeof(uf)))
249 return -EFAULT;
250
251 if (!uf.count) {
252 /* Disabled */
253 filter->count = 0;
254 return 0;
255 }
256
257 alen = ETH_ALEN * uf.count;
258 addr = kmalloc(alen, GFP_KERNEL);
259 if (!addr)
260 return -ENOMEM;
261
262 if (copy_from_user(addr, arg + sizeof(uf), alen)) {
263 err = -EFAULT;
264 goto done;
265 }
266
267 /* The filter is updated without holding any locks. Which is
268 * perfectly safe. We disable it first and in the worst
269 * case we'll accept a few undesired packets. */
270 filter->count = 0;
271 wmb();
272
273 /* Use first set of addresses as an exact filter */
274 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
275 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
276
277 nexact = n;
278
279 /* Remaining multicast addresses are hashed,
280 * unicast will leave the filter disabled. */
281 memset(filter->mask, 0, sizeof(filter->mask));
282 for (; n < uf.count; n++) {
283 if (!is_multicast_ether_addr(addr[n].u)) {
284 err = 0; /* no filter */
285 goto done;
286 }
287 addr_hash_set(filter->mask, addr[n].u);
288 }
289
290 /* For ALLMULTI just set the mask to all ones.
291 * This overrides the mask populated above. */
292 if ((uf.flags & TUN_FLT_ALLMULTI))
293 memset(filter->mask, ~0, sizeof(filter->mask));
294
295 /* Now enable the filter */
296 wmb();
297 filter->count = nexact;
298
299 /* Return the number of exact filters */
300 err = nexact;
301
302done:
303 kfree(addr);
304 return err;
305}
306
307/* Returns: 0 - drop, !=0 - accept */
308static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
309{
310 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
311 * at this point. */
312 struct ethhdr *eh = (struct ethhdr *) skb->data;
313 int i;
314
315 /* Exact match */
316 for (i = 0; i < filter->count; i++)
317 if (!compare_ether_addr(eh->h_dest, filter->addr[i]))
318 return 1;
319
320 /* Inexact match (multicast only) */
321 if (is_multicast_ether_addr(eh->h_dest))
322 return addr_hash_test(filter->mask, eh->h_dest);
323
324 return 0;
325}
326
327/*
328 * Checks whether the packet is accepted or not.
329 * Returns: 0 - drop, !=0 - accept
330 */
331static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
332{
333 if (!filter->count)
334 return 1;
335
336 return run_filter(filter, skb);
337}
338
339/* Network device part of the driver */
340
341static const struct ethtool_ops tun_ethtool_ops;
342
343/* Net device detach from fd. */
344static void tun_net_uninit(struct net_device *dev)
345{
346 struct tun_struct *tun = netdev_priv(dev);
347 struct tun_file *tfile = tun->tfile;
348
349 /* Inform the methods they need to stop using the dev.
350 */
351 if (tfile) {
352 wake_up_all(&tun->wq.wait);
353 if (atomic_dec_and_test(&tfile->count))
354 __tun_detach(tun);
355 }
356}
357
358static void tun_free_netdev(struct net_device *dev)
359{
360 struct tun_struct *tun = netdev_priv(dev);
361
362 sock_put(tun->socket.sk);
363}
364
365/* Net device open. */
366static int tun_net_open(struct net_device *dev)
367{
368 netif_start_queue(dev);
369 return 0;
370}
371
372/* Net device close. */
373static int tun_net_close(struct net_device *dev)
374{
375 netif_stop_queue(dev);
376 return 0;
377}
378
379/* Net device start xmit */
380static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
381{
382 struct tun_struct *tun = netdev_priv(dev);
383
384 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
385
386 /* Drop packet if interface is not attached */
387 if (!tun->tfile)
388 goto drop;
389
390 /* Drop if the filter does not like it.
391 * This is a noop if the filter is disabled.
392 * Filter can be enabled only for the TAP devices. */
393 if (!check_filter(&tun->txflt, skb))
394 goto drop;
395
396 if (tun->socket.sk->sk_filter &&
397 sk_filter(tun->socket.sk, skb))
398 goto drop;
399
400 if (skb_queue_len(&tun->socket.sk->sk_receive_queue) >= dev->tx_queue_len) {
401 if (!(tun->flags & TUN_ONE_QUEUE)) {
402 /* Normal queueing mode. */
403 /* Packet scheduler handles dropping of further packets. */
404 netif_stop_queue(dev);
405
406 /* We won't see all dropped packets individually, so overrun
407 * error is more appropriate. */
408 dev->stats.tx_fifo_errors++;
409 } else {
410 /* Single queue mode.
411 * Driver handles dropping of all packets itself. */
412 goto drop;
413 }
414 }
415
416 /* Orphan the skb - required as we might hang on to it
417 * for indefinite time. */
418 skb_orphan(skb);
419
420 /* Enqueue packet */
421 skb_queue_tail(&tun->socket.sk->sk_receive_queue, skb);
422
423 /* Notify and wake up reader process */
424 if (tun->flags & TUN_FASYNC)
425 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
426 wake_up_interruptible_poll(&tun->wq.wait, POLLIN |
427 POLLRDNORM | POLLRDBAND);
428 return NETDEV_TX_OK;
429
430drop:
431 dev->stats.tx_dropped++;
432 kfree_skb(skb);
433 return NETDEV_TX_OK;
434}
435
436static void tun_net_mclist(struct net_device *dev)
437{
438 /*
439 * This callback is supposed to deal with mc filter in
440 * _rx_ path and has nothing to do with the _tx_ path.
441 * In rx path we always accept everything userspace gives us.
442 */
443}
444
445#define MIN_MTU 68
446#define MAX_MTU 65535
447
448static int
449tun_net_change_mtu(struct net_device *dev, int new_mtu)
450{
451 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
452 return -EINVAL;
453 dev->mtu = new_mtu;
454 return 0;
455}
456
457static u32 tun_net_fix_features(struct net_device *dev, u32 features)
458{
459 struct tun_struct *tun = netdev_priv(dev);
460
461 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
462}
463#ifdef CONFIG_NET_POLL_CONTROLLER
464static void tun_poll_controller(struct net_device *dev)
465{
466 /*
467 * Tun only receives frames when:
468 * 1) the char device endpoint gets data from user space
469 * 2) the tun socket gets a sendmsg call from user space
470 * Since both of those are syncronous operations, we are guaranteed
471 * never to have pending data when we poll for it
472 * so theres nothing to do here but return.
473 * We need this though so netpoll recognizes us as an interface that
474 * supports polling, which enables bridge devices in virt setups to
475 * still use netconsole
476 */
477 return;
478}
479#endif
480static const struct net_device_ops tun_netdev_ops = {
481 .ndo_uninit = tun_net_uninit,
482 .ndo_open = tun_net_open,
483 .ndo_stop = tun_net_close,
484 .ndo_start_xmit = tun_net_xmit,
485 .ndo_change_mtu = tun_net_change_mtu,
486 .ndo_fix_features = tun_net_fix_features,
487#ifdef CONFIG_NET_POLL_CONTROLLER
488 .ndo_poll_controller = tun_poll_controller,
489#endif
490};
491
492static const struct net_device_ops tap_netdev_ops = {
493 .ndo_uninit = tun_net_uninit,
494 .ndo_open = tun_net_open,
495 .ndo_stop = tun_net_close,
496 .ndo_start_xmit = tun_net_xmit,
497 .ndo_change_mtu = tun_net_change_mtu,
498 .ndo_fix_features = tun_net_fix_features,
499 .ndo_set_multicast_list = tun_net_mclist,
500 .ndo_set_mac_address = eth_mac_addr,
501 .ndo_validate_addr = eth_validate_addr,
502#ifdef CONFIG_NET_POLL_CONTROLLER
503 .ndo_poll_controller = tun_poll_controller,
504#endif
505};
506
507/* Initialize net device. */
508static void tun_net_init(struct net_device *dev)
509{
510 struct tun_struct *tun = netdev_priv(dev);
511
512 switch (tun->flags & TUN_TYPE_MASK) {
513 case TUN_TUN_DEV:
514 dev->netdev_ops = &tun_netdev_ops;
515
516 /* Point-to-Point TUN Device */
517 dev->hard_header_len = 0;
518 dev->addr_len = 0;
519 dev->mtu = 1500;
520
521 /* Zero header length */
522 dev->type = ARPHRD_NONE;
523 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
524 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
525 break;
526
527 case TUN_TAP_DEV:
528 dev->netdev_ops = &tap_netdev_ops;
529 /* Ethernet TAP Device */
530 ether_setup(dev);
531 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
532
533 random_ether_addr(dev->dev_addr);
534
535 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
536 break;
537 }
538}
539
540/* Character device part */
541
542/* Poll */
543static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
544{
545 struct tun_file *tfile = file->private_data;
546 struct tun_struct *tun = __tun_get(tfile);
547 struct sock *sk;
548 unsigned int mask = 0;
549
550 if (!tun)
551 return POLLERR;
552
553 sk = tun->socket.sk;
554
555 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
556
557 poll_wait(file, &tun->wq.wait, wait);
558
559 if (!skb_queue_empty(&sk->sk_receive_queue))
560 mask |= POLLIN | POLLRDNORM;
561
562 if (sock_writeable(sk) ||
563 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
564 sock_writeable(sk)))
565 mask |= POLLOUT | POLLWRNORM;
566
567 if (tun->dev->reg_state != NETREG_REGISTERED)
568 mask = POLLERR;
569
570 tun_put(tun);
571 return mask;
572}
573
574/* prepad is the amount to reserve at front. len is length after that.
575 * linear is a hint as to how much to copy (usually headers). */
576static struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
577 size_t prepad, size_t len,
578 size_t linear, int noblock)
579{
580 struct sock *sk = tun->socket.sk;
581 struct sk_buff *skb;
582 int err;
583
584 sock_update_classid(sk);
585
586 /* Under a page? Don't bother with paged skb. */
587 if (prepad + len < PAGE_SIZE || !linear)
588 linear = len;
589
590 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
591 &err);
592 if (!skb)
593 return ERR_PTR(err);
594
595 skb_reserve(skb, prepad);
596 skb_put(skb, linear);
597 skb->data_len = len - linear;
598 skb->len += len - linear;
599
600 return skb;
601}
602
603/* Get packet from user space buffer */
604static ssize_t tun_get_user(struct tun_struct *tun,
605 const struct iovec *iv, size_t count,
606 int noblock)
607{
608 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
609 struct sk_buff *skb;
610 size_t len = count, align = NET_SKB_PAD;
611 struct virtio_net_hdr gso = { 0 };
612 int offset = 0;
613
614 if (!(tun->flags & TUN_NO_PI)) {
615 if ((len -= sizeof(pi)) > count)
616 return -EINVAL;
617
618 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
619 return -EFAULT;
620 offset += sizeof(pi);
621 }
622
623 if (tun->flags & TUN_VNET_HDR) {
624 if ((len -= tun->vnet_hdr_sz) > count)
625 return -EINVAL;
626
627 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
628 return -EFAULT;
629
630 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
631 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
632 gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
633
634 if (gso.hdr_len > len)
635 return -EINVAL;
636 offset += tun->vnet_hdr_sz;
637 }
638
639 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
640 align += NET_IP_ALIGN;
641 if (unlikely(len < ETH_HLEN ||
642 (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
643 return -EINVAL;
644 }
645
646 skb = tun_alloc_skb(tun, align, len, gso.hdr_len, noblock);
647 if (IS_ERR(skb)) {
648 if (PTR_ERR(skb) != -EAGAIN)
649 tun->dev->stats.rx_dropped++;
650 return PTR_ERR(skb);
651 }
652
653 if (skb_copy_datagram_from_iovec(skb, 0, iv, offset, len)) {
654 tun->dev->stats.rx_dropped++;
655 kfree_skb(skb);
656 return -EFAULT;
657 }
658
659 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
660 if (!skb_partial_csum_set(skb, gso.csum_start,
661 gso.csum_offset)) {
662 tun->dev->stats.rx_frame_errors++;
663 kfree_skb(skb);
664 return -EINVAL;
665 }
666 }
667
668 switch (tun->flags & TUN_TYPE_MASK) {
669 case TUN_TUN_DEV:
670 if (tun->flags & TUN_NO_PI) {
671 switch (skb->data[0] & 0xf0) {
672 case 0x40:
673 pi.proto = htons(ETH_P_IP);
674 break;
675 case 0x60:
676 pi.proto = htons(ETH_P_IPV6);
677 break;
678 default:
679 tun->dev->stats.rx_dropped++;
680 kfree_skb(skb);
681 return -EINVAL;
682 }
683 }
684
685 skb_reset_mac_header(skb);
686 skb->protocol = pi.proto;
687 skb->dev = tun->dev;
688 break;
689 case TUN_TAP_DEV:
690 skb->protocol = eth_type_trans(skb, tun->dev);
691 break;
692 }
693
694 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
695 pr_debug("GSO!\n");
696 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
697 case VIRTIO_NET_HDR_GSO_TCPV4:
698 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
699 break;
700 case VIRTIO_NET_HDR_GSO_TCPV6:
701 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
702 break;
703 case VIRTIO_NET_HDR_GSO_UDP:
704 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
705 break;
706 default:
707 tun->dev->stats.rx_frame_errors++;
708 kfree_skb(skb);
709 return -EINVAL;
710 }
711
712 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
713 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
714
715 skb_shinfo(skb)->gso_size = gso.gso_size;
716 if (skb_shinfo(skb)->gso_size == 0) {
717 tun->dev->stats.rx_frame_errors++;
718 kfree_skb(skb);
719 return -EINVAL;
720 }
721
722 /* Header must be checked, and gso_segs computed. */
723 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
724 skb_shinfo(skb)->gso_segs = 0;
725 }
726
727 netif_rx_ni(skb);
728
729 tun->dev->stats.rx_packets++;
730 tun->dev->stats.rx_bytes += len;
731
732 return count;
733}
734
735static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
736 unsigned long count, loff_t pos)
737{
738 struct file *file = iocb->ki_filp;
739 struct tun_struct *tun = tun_get(file);
740 ssize_t result;
741
742 if (!tun)
743 return -EBADFD;
744
745 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
746
747 result = tun_get_user(tun, iv, iov_length(iv, count),
748 file->f_flags & O_NONBLOCK);
749
750 tun_put(tun);
751 return result;
752}
753
754/* Put packet to the user space buffer */
755static ssize_t tun_put_user(struct tun_struct *tun,
756 struct sk_buff *skb,
757 const struct iovec *iv, int len)
758{
759 struct tun_pi pi = { 0, skb->protocol };
760 ssize_t total = 0;
761
762 if (!(tun->flags & TUN_NO_PI)) {
763 if ((len -= sizeof(pi)) < 0)
764 return -EINVAL;
765
766 if (len < skb->len) {
767 /* Packet will be striped */
768 pi.flags |= TUN_PKT_STRIP;
769 }
770
771 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
772 return -EFAULT;
773 total += sizeof(pi);
774 }
775
776 if (tun->flags & TUN_VNET_HDR) {
777 struct virtio_net_hdr gso = { 0 }; /* no info leak */
778 if ((len -= tun->vnet_hdr_sz) < 0)
779 return -EINVAL;
780
781 if (skb_is_gso(skb)) {
782 struct skb_shared_info *sinfo = skb_shinfo(skb);
783
784 /* This is a hint as to how much should be linear. */
785 gso.hdr_len = skb_headlen(skb);
786 gso.gso_size = sinfo->gso_size;
787 if (sinfo->gso_type & SKB_GSO_TCPV4)
788 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
789 else if (sinfo->gso_type & SKB_GSO_TCPV6)
790 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
791 else if (sinfo->gso_type & SKB_GSO_UDP)
792 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
793 else {
794 pr_err("unexpected GSO type: "
795 "0x%x, gso_size %d, hdr_len %d\n",
796 sinfo->gso_type, gso.gso_size,
797 gso.hdr_len);
798 print_hex_dump(KERN_ERR, "tun: ",
799 DUMP_PREFIX_NONE,
800 16, 1, skb->head,
801 min((int)gso.hdr_len, 64), true);
802 WARN_ON_ONCE(1);
803 return -EINVAL;
804 }
805 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
806 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
807 } else
808 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
809
810 if (skb->ip_summed == CHECKSUM_PARTIAL) {
811 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
812 gso.csum_start = skb_checksum_start_offset(skb);
813 gso.csum_offset = skb->csum_offset;
814 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
815 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
816 } /* else everything is zero */
817
818 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
819 sizeof(gso))))
820 return -EFAULT;
821 total += tun->vnet_hdr_sz;
822 }
823
824 len = min_t(int, skb->len, len);
825
826 skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
827 total += skb->len;
828
829 tun->dev->stats.tx_packets++;
830 tun->dev->stats.tx_bytes += len;
831
832 return total;
833}
834
835static ssize_t tun_do_read(struct tun_struct *tun,
836 struct kiocb *iocb, const struct iovec *iv,
837 ssize_t len, int noblock)
838{
839 DECLARE_WAITQUEUE(wait, current);
840 struct sk_buff *skb;
841 ssize_t ret = 0;
842
843 tun_debug(KERN_INFO, tun, "tun_chr_read\n");
844
845 if (unlikely(!noblock))
846 add_wait_queue(&tun->wq.wait, &wait);
847 while (len) {
848 current->state = TASK_INTERRUPTIBLE;
849
850 /* Read frames from the queue */
851 if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) {
852 if (noblock) {
853 ret = -EAGAIN;
854 break;
855 }
856 if (signal_pending(current)) {
857 ret = -ERESTARTSYS;
858 break;
859 }
860 if (tun->dev->reg_state != NETREG_REGISTERED) {
861 ret = -EIO;
862 break;
863 }
864
865 /* Nothing to read, let's sleep */
866 schedule();
867 continue;
868 }
869 netif_wake_queue(tun->dev);
870
871 ret = tun_put_user(tun, skb, iv, len);
872 kfree_skb(skb);
873 break;
874 }
875
876 current->state = TASK_RUNNING;
877 if (unlikely(!noblock))
878 remove_wait_queue(&tun->wq.wait, &wait);
879
880 return ret;
881}
882
883static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
884 unsigned long count, loff_t pos)
885{
886 struct file *file = iocb->ki_filp;
887 struct tun_file *tfile = file->private_data;
888 struct tun_struct *tun = __tun_get(tfile);
889 ssize_t len, ret;
890
891 if (!tun)
892 return -EBADFD;
893 len = iov_length(iv, count);
894 if (len < 0) {
895 ret = -EINVAL;
896 goto out;
897 }
898
899 ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK);
900 ret = min_t(ssize_t, ret, len);
901out:
902 tun_put(tun);
903 return ret;
904}
905
906static void tun_setup(struct net_device *dev)
907{
908 struct tun_struct *tun = netdev_priv(dev);
909
910 tun->owner = -1;
911 tun->group = -1;
912
913 dev->ethtool_ops = &tun_ethtool_ops;
914 dev->destructor = tun_free_netdev;
915}
916
917/* Trivial set of netlink ops to allow deleting tun or tap
918 * device with netlink.
919 */
920static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
921{
922 return -EINVAL;
923}
924
925static struct rtnl_link_ops tun_link_ops __read_mostly = {
926 .kind = DRV_NAME,
927 .priv_size = sizeof(struct tun_struct),
928 .setup = tun_setup,
929 .validate = tun_validate,
930};
931
932static void tun_sock_write_space(struct sock *sk)
933{
934 struct tun_struct *tun;
935 wait_queue_head_t *wqueue;
936
937 if (!sock_writeable(sk))
938 return;
939
940 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
941 return;
942
943 wqueue = sk_sleep(sk);
944 if (wqueue && waitqueue_active(wqueue))
945 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
946 POLLWRNORM | POLLWRBAND);
947
948 tun = tun_sk(sk)->tun;
949 kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
950}
951
952static void tun_sock_destruct(struct sock *sk)
953{
954 free_netdev(tun_sk(sk)->tun->dev);
955}
956
957static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
958 struct msghdr *m, size_t total_len)
959{
960 struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
961 return tun_get_user(tun, m->msg_iov, total_len,
962 m->msg_flags & MSG_DONTWAIT);
963}
964
965static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
966 struct msghdr *m, size_t total_len,
967 int flags)
968{
969 struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
970 int ret;
971 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
972 return -EINVAL;
973 ret = tun_do_read(tun, iocb, m->msg_iov, total_len,
974 flags & MSG_DONTWAIT);
975 if (ret > total_len) {
976 m->msg_flags |= MSG_TRUNC;
977 ret = flags & MSG_TRUNC ? ret : total_len;
978 }
979 return ret;
980}
981
982/* Ops structure to mimic raw sockets with tun */
983static const struct proto_ops tun_socket_ops = {
984 .sendmsg = tun_sendmsg,
985 .recvmsg = tun_recvmsg,
986};
987
988static struct proto tun_proto = {
989 .name = "tun",
990 .owner = THIS_MODULE,
991 .obj_size = sizeof(struct tun_sock),
992};
993
994static int tun_flags(struct tun_struct *tun)
995{
996 int flags = 0;
997
998 if (tun->flags & TUN_TUN_DEV)
999 flags |= IFF_TUN;
1000 else
1001 flags |= IFF_TAP;
1002
1003 if (tun->flags & TUN_NO_PI)
1004 flags |= IFF_NO_PI;
1005
1006 if (tun->flags & TUN_ONE_QUEUE)
1007 flags |= IFF_ONE_QUEUE;
1008
1009 if (tun->flags & TUN_VNET_HDR)
1010 flags |= IFF_VNET_HDR;
1011
1012 return flags;
1013}
1014
1015static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1016 char *buf)
1017{
1018 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1019 return sprintf(buf, "0x%x\n", tun_flags(tun));
1020}
1021
1022static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1023 char *buf)
1024{
1025 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1026 return sprintf(buf, "%d\n", tun->owner);
1027}
1028
1029static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1030 char *buf)
1031{
1032 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1033 return sprintf(buf, "%d\n", tun->group);
1034}
1035
1036static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1037static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1038static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1039
1040static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1041{
1042 struct sock *sk;
1043 struct tun_struct *tun;
1044 struct net_device *dev;
1045 int err;
1046
1047 dev = __dev_get_by_name(net, ifr->ifr_name);
1048 if (dev) {
1049 const struct cred *cred = current_cred();
1050
1051 if (ifr->ifr_flags & IFF_TUN_EXCL)
1052 return -EBUSY;
1053 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1054 tun = netdev_priv(dev);
1055 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1056 tun = netdev_priv(dev);
1057 else
1058 return -EINVAL;
1059
1060 if (((tun->owner != -1 && cred->euid != tun->owner) ||
1061 (tun->group != -1 && !in_egroup_p(tun->group))) &&
1062 !capable(CAP_NET_ADMIN))
1063 return -EPERM;
1064 err = security_tun_dev_attach(tun->socket.sk);
1065 if (err < 0)
1066 return err;
1067
1068 err = tun_attach(tun, file);
1069 if (err < 0)
1070 return err;
1071 }
1072 else {
1073 char *name;
1074 unsigned long flags = 0;
1075
1076 if (!capable(CAP_NET_ADMIN))
1077 return -EPERM;
1078 err = security_tun_dev_create();
1079 if (err < 0)
1080 return err;
1081
1082 /* Set dev type */
1083 if (ifr->ifr_flags & IFF_TUN) {
1084 /* TUN device */
1085 flags |= TUN_TUN_DEV;
1086 name = "tun%d";
1087 } else if (ifr->ifr_flags & IFF_TAP) {
1088 /* TAP device */
1089 flags |= TUN_TAP_DEV;
1090 name = "tap%d";
1091 } else
1092 return -EINVAL;
1093
1094 if (*ifr->ifr_name)
1095 name = ifr->ifr_name;
1096
1097 dev = alloc_netdev(sizeof(struct tun_struct), name,
1098 tun_setup);
1099 if (!dev)
1100 return -ENOMEM;
1101
1102 dev_net_set(dev, net);
1103 dev->rtnl_link_ops = &tun_link_ops;
1104
1105 tun = netdev_priv(dev);
1106 tun->dev = dev;
1107 tun->flags = flags;
1108 tun->txflt.count = 0;
1109 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1110
1111 err = -ENOMEM;
1112 sk = sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
1113 if (!sk)
1114 goto err_free_dev;
1115
1116 tun->socket.wq = &tun->wq;
1117 init_waitqueue_head(&tun->wq.wait);
1118 tun->socket.ops = &tun_socket_ops;
1119 sock_init_data(&tun->socket, sk);
1120 sk->sk_write_space = tun_sock_write_space;
1121 sk->sk_sndbuf = INT_MAX;
1122
1123 tun_sk(sk)->tun = tun;
1124
1125 security_tun_dev_post_create(sk);
1126
1127 tun_net_init(dev);
1128
1129 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1130 TUN_USER_FEATURES;
1131 dev->features = dev->hw_features;
1132
1133 err = register_netdevice(tun->dev);
1134 if (err < 0)
1135 goto err_free_sk;
1136
1137 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1138 device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1139 device_create_file(&tun->dev->dev, &dev_attr_group))
1140 pr_err("Failed to create tun sysfs files\n");
1141
1142 sk->sk_destruct = tun_sock_destruct;
1143
1144 err = tun_attach(tun, file);
1145 if (err < 0)
1146 goto failed;
1147 }
1148
1149 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1150
1151 if (ifr->ifr_flags & IFF_NO_PI)
1152 tun->flags |= TUN_NO_PI;
1153 else
1154 tun->flags &= ~TUN_NO_PI;
1155
1156 if (ifr->ifr_flags & IFF_ONE_QUEUE)
1157 tun->flags |= TUN_ONE_QUEUE;
1158 else
1159 tun->flags &= ~TUN_ONE_QUEUE;
1160
1161 if (ifr->ifr_flags & IFF_VNET_HDR)
1162 tun->flags |= TUN_VNET_HDR;
1163 else
1164 tun->flags &= ~TUN_VNET_HDR;
1165
1166 /* Make sure persistent devices do not get stuck in
1167 * xoff state.
1168 */
1169 if (netif_running(tun->dev))
1170 netif_wake_queue(tun->dev);
1171
1172 strcpy(ifr->ifr_name, tun->dev->name);
1173 return 0;
1174
1175 err_free_sk:
1176 sock_put(sk);
1177 err_free_dev:
1178 free_netdev(dev);
1179 failed:
1180 return err;
1181}
1182
1183static int tun_get_iff(struct net *net, struct tun_struct *tun,
1184 struct ifreq *ifr)
1185{
1186 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1187
1188 strcpy(ifr->ifr_name, tun->dev->name);
1189
1190 ifr->ifr_flags = tun_flags(tun);
1191
1192 return 0;
1193}
1194
1195/* This is like a cut-down ethtool ops, except done via tun fd so no
1196 * privs required. */
1197static int set_offload(struct tun_struct *tun, unsigned long arg)
1198{
1199 u32 features = 0;
1200
1201 if (arg & TUN_F_CSUM) {
1202 features |= NETIF_F_HW_CSUM;
1203 arg &= ~TUN_F_CSUM;
1204
1205 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1206 if (arg & TUN_F_TSO_ECN) {
1207 features |= NETIF_F_TSO_ECN;
1208 arg &= ~TUN_F_TSO_ECN;
1209 }
1210 if (arg & TUN_F_TSO4)
1211 features |= NETIF_F_TSO;
1212 if (arg & TUN_F_TSO6)
1213 features |= NETIF_F_TSO6;
1214 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1215 }
1216
1217 if (arg & TUN_F_UFO) {
1218 features |= NETIF_F_UFO;
1219 arg &= ~TUN_F_UFO;
1220 }
1221 }
1222
1223 /* This gives the user a way to test for new features in future by
1224 * trying to set them. */
1225 if (arg)
1226 return -EINVAL;
1227
1228 tun->set_features = features;
1229 netdev_update_features(tun->dev);
1230
1231 return 0;
1232}
1233
1234static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1235 unsigned long arg, int ifreq_len)
1236{
1237 struct tun_file *tfile = file->private_data;
1238 struct tun_struct *tun;
1239 void __user* argp = (void __user*)arg;
1240 struct sock_fprog fprog;
1241 struct ifreq ifr;
1242 int sndbuf;
1243 int vnet_hdr_sz;
1244 int ret;
1245
1246 if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
1247 if (copy_from_user(&ifr, argp, ifreq_len))
1248 return -EFAULT;
1249
1250 if (cmd == TUNGETFEATURES) {
1251 /* Currently this just means: "what IFF flags are valid?".
1252 * This is needed because we never checked for invalid flags on
1253 * TUNSETIFF. */
1254 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1255 IFF_VNET_HDR,
1256 (unsigned int __user*)argp);
1257 }
1258
1259 rtnl_lock();
1260
1261 tun = __tun_get(tfile);
1262 if (cmd == TUNSETIFF && !tun) {
1263 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1264
1265 ret = tun_set_iff(tfile->net, file, &ifr);
1266
1267 if (ret)
1268 goto unlock;
1269
1270 if (copy_to_user(argp, &ifr, ifreq_len))
1271 ret = -EFAULT;
1272 goto unlock;
1273 }
1274
1275 ret = -EBADFD;
1276 if (!tun)
1277 goto unlock;
1278
1279 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %d\n", cmd);
1280
1281 ret = 0;
1282 switch (cmd) {
1283 case TUNGETIFF:
1284 ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1285 if (ret)
1286 break;
1287
1288 if (copy_to_user(argp, &ifr, ifreq_len))
1289 ret = -EFAULT;
1290 break;
1291
1292 case TUNSETNOCSUM:
1293 /* Disable/Enable checksum */
1294
1295 /* [unimplemented] */
1296 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1297 arg ? "disabled" : "enabled");
1298 break;
1299
1300 case TUNSETPERSIST:
1301 /* Disable/Enable persist mode */
1302 if (arg)
1303 tun->flags |= TUN_PERSIST;
1304 else
1305 tun->flags &= ~TUN_PERSIST;
1306
1307 tun_debug(KERN_INFO, tun, "persist %s\n",
1308 arg ? "enabled" : "disabled");
1309 break;
1310
1311 case TUNSETOWNER:
1312 /* Set owner of the device */
1313 tun->owner = (uid_t) arg;
1314
1315 tun_debug(KERN_INFO, tun, "owner set to %d\n", tun->owner);
1316 break;
1317
1318 case TUNSETGROUP:
1319 /* Set group of the device */
1320 tun->group= (gid_t) arg;
1321
1322 tun_debug(KERN_INFO, tun, "group set to %d\n", tun->group);
1323 break;
1324
1325 case TUNSETLINK:
1326 /* Only allow setting the type when the interface is down */
1327 if (tun->dev->flags & IFF_UP) {
1328 tun_debug(KERN_INFO, tun,
1329 "Linktype set failed because interface is up\n");
1330 ret = -EBUSY;
1331 } else {
1332 tun->dev->type = (int) arg;
1333 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1334 tun->dev->type);
1335 ret = 0;
1336 }
1337 break;
1338
1339#ifdef TUN_DEBUG
1340 case TUNSETDEBUG:
1341 tun->debug = arg;
1342 break;
1343#endif
1344 case TUNSETOFFLOAD:
1345 ret = set_offload(tun, arg);
1346 break;
1347
1348 case TUNSETTXFILTER:
1349 /* Can be set only for TAPs */
1350 ret = -EINVAL;
1351 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1352 break;
1353 ret = update_filter(&tun->txflt, (void __user *)arg);
1354 break;
1355
1356 case SIOCGIFHWADDR:
1357 /* Get hw address */
1358 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1359 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1360 if (copy_to_user(argp, &ifr, ifreq_len))
1361 ret = -EFAULT;
1362 break;
1363
1364 case SIOCSIFHWADDR:
1365 /* Set hw address */
1366 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1367 ifr.ifr_hwaddr.sa_data);
1368
1369 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1370 break;
1371
1372 case TUNGETSNDBUF:
1373 sndbuf = tun->socket.sk->sk_sndbuf;
1374 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1375 ret = -EFAULT;
1376 break;
1377
1378 case TUNSETSNDBUF:
1379 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1380 ret = -EFAULT;
1381 break;
1382 }
1383
1384 tun->socket.sk->sk_sndbuf = sndbuf;
1385 break;
1386
1387 case TUNGETVNETHDRSZ:
1388 vnet_hdr_sz = tun->vnet_hdr_sz;
1389 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
1390 ret = -EFAULT;
1391 break;
1392
1393 case TUNSETVNETHDRSZ:
1394 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
1395 ret = -EFAULT;
1396 break;
1397 }
1398 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
1399 ret = -EINVAL;
1400 break;
1401 }
1402
1403 tun->vnet_hdr_sz = vnet_hdr_sz;
1404 break;
1405
1406 case TUNATTACHFILTER:
1407 /* Can be set only for TAPs */
1408 ret = -EINVAL;
1409 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1410 break;
1411 ret = -EFAULT;
1412 if (copy_from_user(&fprog, argp, sizeof(fprog)))
1413 break;
1414
1415 ret = sk_attach_filter(&fprog, tun->socket.sk);
1416 break;
1417
1418 case TUNDETACHFILTER:
1419 /* Can be set only for TAPs */
1420 ret = -EINVAL;
1421 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1422 break;
1423 ret = sk_detach_filter(tun->socket.sk);
1424 break;
1425
1426 default:
1427 ret = -EINVAL;
1428 break;
1429 }
1430
1431unlock:
1432 rtnl_unlock();
1433 if (tun)
1434 tun_put(tun);
1435 return ret;
1436}
1437
1438static long tun_chr_ioctl(struct file *file,
1439 unsigned int cmd, unsigned long arg)
1440{
1441 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
1442}
1443
1444#ifdef CONFIG_COMPAT
1445static long tun_chr_compat_ioctl(struct file *file,
1446 unsigned int cmd, unsigned long arg)
1447{
1448 switch (cmd) {
1449 case TUNSETIFF:
1450 case TUNGETIFF:
1451 case TUNSETTXFILTER:
1452 case TUNGETSNDBUF:
1453 case TUNSETSNDBUF:
1454 case SIOCGIFHWADDR:
1455 case SIOCSIFHWADDR:
1456 arg = (unsigned long)compat_ptr(arg);
1457 break;
1458 default:
1459 arg = (compat_ulong_t)arg;
1460 break;
1461 }
1462
1463 /*
1464 * compat_ifreq is shorter than ifreq, so we must not access beyond
1465 * the end of that structure. All fields that are used in this
1466 * driver are compatible though, we don't need to convert the
1467 * contents.
1468 */
1469 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
1470}
1471#endif /* CONFIG_COMPAT */
1472
1473static int tun_chr_fasync(int fd, struct file *file, int on)
1474{
1475 struct tun_struct *tun = tun_get(file);
1476 int ret;
1477
1478 if (!tun)
1479 return -EBADFD;
1480
1481 tun_debug(KERN_INFO, tun, "tun_chr_fasync %d\n", on);
1482
1483 if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1484 goto out;
1485
1486 if (on) {
1487 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1488 if (ret)
1489 goto out;
1490 tun->flags |= TUN_FASYNC;
1491 } else
1492 tun->flags &= ~TUN_FASYNC;
1493 ret = 0;
1494out:
1495 tun_put(tun);
1496 return ret;
1497}
1498
1499static int tun_chr_open(struct inode *inode, struct file * file)
1500{
1501 struct tun_file *tfile;
1502
1503 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
1504
1505 tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1506 if (!tfile)
1507 return -ENOMEM;
1508 atomic_set(&tfile->count, 0);
1509 tfile->tun = NULL;
1510 tfile->net = get_net(current->nsproxy->net_ns);
1511 file->private_data = tfile;
1512 return 0;
1513}
1514
1515static int tun_chr_close(struct inode *inode, struct file *file)
1516{
1517 struct tun_file *tfile = file->private_data;
1518 struct tun_struct *tun;
1519
1520 tun = __tun_get(tfile);
1521 if (tun) {
1522 struct net_device *dev = tun->dev;
1523
1524 tun_debug(KERN_INFO, tun, "tun_chr_close\n");
1525
1526 __tun_detach(tun);
1527
1528 /* If desirable, unregister the netdevice. */
1529 if (!(tun->flags & TUN_PERSIST)) {
1530 rtnl_lock();
1531 if (dev->reg_state == NETREG_REGISTERED)
1532 unregister_netdevice(dev);
1533 rtnl_unlock();
1534 }
1535 }
1536
1537 tun = tfile->tun;
1538 if (tun)
1539 sock_put(tun->socket.sk);
1540
1541 put_net(tfile->net);
1542 kfree(tfile);
1543
1544 return 0;
1545}
1546
1547static const struct file_operations tun_fops = {
1548 .owner = THIS_MODULE,
1549 .llseek = no_llseek,
1550 .read = do_sync_read,
1551 .aio_read = tun_chr_aio_read,
1552 .write = do_sync_write,
1553 .aio_write = tun_chr_aio_write,
1554 .poll = tun_chr_poll,
1555 .unlocked_ioctl = tun_chr_ioctl,
1556#ifdef CONFIG_COMPAT
1557 .compat_ioctl = tun_chr_compat_ioctl,
1558#endif
1559 .open = tun_chr_open,
1560 .release = tun_chr_close,
1561 .fasync = tun_chr_fasync
1562};
1563
1564static struct miscdevice tun_miscdev = {
1565 .minor = TUN_MINOR,
1566 .name = "tun",
1567 .nodename = "net/tun",
1568 .fops = &tun_fops,
1569};
1570
1571/* ethtool interface */
1572
1573static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1574{
1575 cmd->supported = 0;
1576 cmd->advertising = 0;
1577 ethtool_cmd_speed_set(cmd, SPEED_10);
1578 cmd->duplex = DUPLEX_FULL;
1579 cmd->port = PORT_TP;
1580 cmd->phy_address = 0;
1581 cmd->transceiver = XCVR_INTERNAL;
1582 cmd->autoneg = AUTONEG_DISABLE;
1583 cmd->maxtxpkt = 0;
1584 cmd->maxrxpkt = 0;
1585 return 0;
1586}
1587
1588static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1589{
1590 struct tun_struct *tun = netdev_priv(dev);
1591
1592 strcpy(info->driver, DRV_NAME);
1593 strcpy(info->version, DRV_VERSION);
1594 strcpy(info->fw_version, "N/A");
1595
1596 switch (tun->flags & TUN_TYPE_MASK) {
1597 case TUN_TUN_DEV:
1598 strcpy(info->bus_info, "tun");
1599 break;
1600 case TUN_TAP_DEV:
1601 strcpy(info->bus_info, "tap");
1602 break;
1603 }
1604}
1605
1606static u32 tun_get_msglevel(struct net_device *dev)
1607{
1608#ifdef TUN_DEBUG
1609 struct tun_struct *tun = netdev_priv(dev);
1610 return tun->debug;
1611#else
1612 return -EOPNOTSUPP;
1613#endif
1614}
1615
1616static void tun_set_msglevel(struct net_device *dev, u32 value)
1617{
1618#ifdef TUN_DEBUG
1619 struct tun_struct *tun = netdev_priv(dev);
1620 tun->debug = value;
1621#endif
1622}
1623
1624static const struct ethtool_ops tun_ethtool_ops = {
1625 .get_settings = tun_get_settings,
1626 .get_drvinfo = tun_get_drvinfo,
1627 .get_msglevel = tun_get_msglevel,
1628 .set_msglevel = tun_set_msglevel,
1629 .get_link = ethtool_op_get_link,
1630};
1631
1632
1633static int __init tun_init(void)
1634{
1635 int ret = 0;
1636
1637 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1638 pr_info("%s\n", DRV_COPYRIGHT);
1639
1640 ret = rtnl_link_register(&tun_link_ops);
1641 if (ret) {
1642 pr_err("Can't register link_ops\n");
1643 goto err_linkops;
1644 }
1645
1646 ret = misc_register(&tun_miscdev);
1647 if (ret) {
1648 pr_err("Can't register misc device %d\n", TUN_MINOR);
1649 goto err_misc;
1650 }
1651 return 0;
1652err_misc:
1653 rtnl_link_unregister(&tun_link_ops);
1654err_linkops:
1655 return ret;
1656}
1657
1658static void tun_cleanup(void)
1659{
1660 misc_deregister(&tun_miscdev);
1661 rtnl_link_unregister(&tun_link_ops);
1662}
1663
1664/* Get an underlying socket object from tun file. Returns error unless file is
1665 * attached to a device. The returned object works like a packet socket, it
1666 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
1667 * holding a reference to the file for as long as the socket is in use. */
1668struct socket *tun_get_socket(struct file *file)
1669{
1670 struct tun_struct *tun;
1671 if (file->f_op != &tun_fops)
1672 return ERR_PTR(-EINVAL);
1673 tun = tun_get(file);
1674 if (!tun)
1675 return ERR_PTR(-EBADFD);
1676 tun_put(tun);
1677 return &tun->socket;
1678}
1679EXPORT_SYMBOL_GPL(tun_get_socket);
1680
1681module_init(tun_init);
1682module_exit(tun_cleanup);
1683MODULE_DESCRIPTION(DRV_DESCRIPTION);
1684MODULE_AUTHOR(DRV_COPYRIGHT);
1685MODULE_LICENSE("GPL");
1686MODULE_ALIAS_MISCDEV(TUN_MINOR);
1687MODULE_ALIAS("devname:net/tun");
1/*
2 * TUN - Universal TUN/TAP device driver.
3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
16 */
17
18/*
19 * Changes:
20 *
21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
22 * Add TUNSETLINK ioctl to set the link encapsulation
23 *
24 * Mark Smith <markzzzsmith@yahoo.com.au>
25 * Use eth_random_addr() for tap MAC address.
26 *
27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
28 * Fixes in packet dropping, queue length setting and queue wakeup.
29 * Increased default tx queue length.
30 * Added ethtool API.
31 * Minor cleanups
32 *
33 * Daniel Podlejski <underley@underley.eu.org>
34 * Modifications for 2.3.99-pre5 kernel.
35 */
36
37#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
38
39#define DRV_NAME "tun"
40#define DRV_VERSION "1.6"
41#define DRV_DESCRIPTION "Universal TUN/TAP device driver"
42#define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
43
44#include <linux/module.h>
45#include <linux/errno.h>
46#include <linux/kernel.h>
47#include <linux/major.h>
48#include <linux/slab.h>
49#include <linux/poll.h>
50#include <linux/fcntl.h>
51#include <linux/init.h>
52#include <linux/skbuff.h>
53#include <linux/netdevice.h>
54#include <linux/etherdevice.h>
55#include <linux/miscdevice.h>
56#include <linux/ethtool.h>
57#include <linux/rtnetlink.h>
58#include <linux/compat.h>
59#include <linux/if.h>
60#include <linux/if_arp.h>
61#include <linux/if_ether.h>
62#include <linux/if_tun.h>
63#include <linux/if_vlan.h>
64#include <linux/crc32.h>
65#include <linux/nsproxy.h>
66#include <linux/virtio_net.h>
67#include <linux/rcupdate.h>
68#include <net/net_namespace.h>
69#include <net/netns/generic.h>
70#include <net/rtnetlink.h>
71#include <net/sock.h>
72#include <linux/seq_file.h>
73#include <linux/uio.h>
74#include <linux/skb_array.h>
75
76#include <linux/uaccess.h>
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/* TUN device flags */
108
109/* IFF_ATTACH_QUEUE is never stored in device flags,
110 * overload it to mean fasync when stored there.
111 */
112#define TUN_FASYNC IFF_ATTACH_QUEUE
113/* High bits in flags field are unused. */
114#define TUN_VNET_LE 0x80000000
115#define TUN_VNET_BE 0x40000000
116
117#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
118 IFF_MULTI_QUEUE)
119#define GOODCOPY_LEN 128
120
121#define FLT_EXACT_COUNT 8
122struct tap_filter {
123 unsigned int count; /* Number of addrs. Zero means disabled */
124 u32 mask[2]; /* Mask of the hashed addrs */
125 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
126};
127
128/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
129 * to max number of VCPUs in guest. */
130#define MAX_TAP_QUEUES 256
131#define MAX_TAP_FLOWS 4096
132
133#define TUN_FLOW_EXPIRE (3 * HZ)
134
135struct tun_pcpu_stats {
136 u64 rx_packets;
137 u64 rx_bytes;
138 u64 tx_packets;
139 u64 tx_bytes;
140 struct u64_stats_sync syncp;
141 u32 rx_dropped;
142 u32 tx_dropped;
143 u32 rx_frame_errors;
144};
145
146/* A tun_file connects an open character device to a tuntap netdevice. It
147 * also contains all socket related structures (except sock_fprog and tap_filter)
148 * to serve as one transmit queue for tuntap device. The sock_fprog and
149 * tap_filter were kept in tun_struct since they were used for filtering for the
150 * netdevice not for a specific queue (at least I didn't see the requirement for
151 * this).
152 *
153 * RCU usage:
154 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
155 * other can only be read while rcu_read_lock or rtnl_lock is held.
156 */
157struct tun_file {
158 struct sock sk;
159 struct socket socket;
160 struct socket_wq wq;
161 struct tun_struct __rcu *tun;
162 struct fasync_struct *fasync;
163 /* only used for fasnyc */
164 unsigned int flags;
165 union {
166 u16 queue_index;
167 unsigned int ifindex;
168 };
169 struct list_head next;
170 struct tun_struct *detached;
171 struct skb_array tx_array;
172};
173
174struct tun_flow_entry {
175 struct hlist_node hash_link;
176 struct rcu_head rcu;
177 struct tun_struct *tun;
178
179 u32 rxhash;
180 u32 rps_rxhash;
181 int queue_index;
182 unsigned long updated;
183};
184
185#define TUN_NUM_FLOW_ENTRIES 1024
186
187/* Since the socket were moved to tun_file, to preserve the behavior of persist
188 * device, socket filter, sndbuf and vnet header size were restore when the
189 * file were attached to a persist device.
190 */
191struct tun_struct {
192 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
193 unsigned int numqueues;
194 unsigned int flags;
195 kuid_t owner;
196 kgid_t group;
197
198 struct net_device *dev;
199 netdev_features_t set_features;
200#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
201 NETIF_F_TSO6|NETIF_F_UFO)
202
203 int align;
204 int vnet_hdr_sz;
205 int sndbuf;
206 struct tap_filter txflt;
207 struct sock_fprog fprog;
208 /* protected by rtnl lock */
209 bool filter_attached;
210#ifdef TUN_DEBUG
211 int debug;
212#endif
213 spinlock_t lock;
214 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
215 struct timer_list flow_gc_timer;
216 unsigned long ageing_time;
217 unsigned int numdisabled;
218 struct list_head disabled;
219 void *security;
220 u32 flow_count;
221 struct tun_pcpu_stats __percpu *pcpu_stats;
222};
223
224#ifdef CONFIG_TUN_VNET_CROSS_LE
225static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
226{
227 return tun->flags & TUN_VNET_BE ? false :
228 virtio_legacy_is_little_endian();
229}
230
231static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
232{
233 int be = !!(tun->flags & TUN_VNET_BE);
234
235 if (put_user(be, argp))
236 return -EFAULT;
237
238 return 0;
239}
240
241static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
242{
243 int be;
244
245 if (get_user(be, argp))
246 return -EFAULT;
247
248 if (be)
249 tun->flags |= TUN_VNET_BE;
250 else
251 tun->flags &= ~TUN_VNET_BE;
252
253 return 0;
254}
255#else
256static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
257{
258 return virtio_legacy_is_little_endian();
259}
260
261static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
262{
263 return -EINVAL;
264}
265
266static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
267{
268 return -EINVAL;
269}
270#endif /* CONFIG_TUN_VNET_CROSS_LE */
271
272static inline bool tun_is_little_endian(struct tun_struct *tun)
273{
274 return tun->flags & TUN_VNET_LE ||
275 tun_legacy_is_little_endian(tun);
276}
277
278static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
279{
280 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
281}
282
283static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
284{
285 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
286}
287
288static inline u32 tun_hashfn(u32 rxhash)
289{
290 return rxhash & 0x3ff;
291}
292
293static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
294{
295 struct tun_flow_entry *e;
296
297 hlist_for_each_entry_rcu(e, head, hash_link) {
298 if (e->rxhash == rxhash)
299 return e;
300 }
301 return NULL;
302}
303
304static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
305 struct hlist_head *head,
306 u32 rxhash, u16 queue_index)
307{
308 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
309
310 if (e) {
311 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
312 rxhash, queue_index);
313 e->updated = jiffies;
314 e->rxhash = rxhash;
315 e->rps_rxhash = 0;
316 e->queue_index = queue_index;
317 e->tun = tun;
318 hlist_add_head_rcu(&e->hash_link, head);
319 ++tun->flow_count;
320 }
321 return e;
322}
323
324static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
325{
326 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
327 e->rxhash, e->queue_index);
328 hlist_del_rcu(&e->hash_link);
329 kfree_rcu(e, rcu);
330 --tun->flow_count;
331}
332
333static void tun_flow_flush(struct tun_struct *tun)
334{
335 int i;
336
337 spin_lock_bh(&tun->lock);
338 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
339 struct tun_flow_entry *e;
340 struct hlist_node *n;
341
342 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
343 tun_flow_delete(tun, e);
344 }
345 spin_unlock_bh(&tun->lock);
346}
347
348static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
349{
350 int i;
351
352 spin_lock_bh(&tun->lock);
353 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
354 struct tun_flow_entry *e;
355 struct hlist_node *n;
356
357 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
358 if (e->queue_index == queue_index)
359 tun_flow_delete(tun, e);
360 }
361 }
362 spin_unlock_bh(&tun->lock);
363}
364
365static void tun_flow_cleanup(unsigned long data)
366{
367 struct tun_struct *tun = (struct tun_struct *)data;
368 unsigned long delay = tun->ageing_time;
369 unsigned long next_timer = jiffies + delay;
370 unsigned long count = 0;
371 int i;
372
373 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
374
375 spin_lock_bh(&tun->lock);
376 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
377 struct tun_flow_entry *e;
378 struct hlist_node *n;
379
380 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
381 unsigned long this_timer;
382 count++;
383 this_timer = e->updated + delay;
384 if (time_before_eq(this_timer, jiffies))
385 tun_flow_delete(tun, e);
386 else if (time_before(this_timer, next_timer))
387 next_timer = this_timer;
388 }
389 }
390
391 if (count)
392 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
393 spin_unlock_bh(&tun->lock);
394}
395
396static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
397 struct tun_file *tfile)
398{
399 struct hlist_head *head;
400 struct tun_flow_entry *e;
401 unsigned long delay = tun->ageing_time;
402 u16 queue_index = tfile->queue_index;
403
404 if (!rxhash)
405 return;
406 else
407 head = &tun->flows[tun_hashfn(rxhash)];
408
409 rcu_read_lock();
410
411 /* We may get a very small possibility of OOO during switching, not
412 * worth to optimize.*/
413 if (tun->numqueues == 1 || tfile->detached)
414 goto unlock;
415
416 e = tun_flow_find(head, rxhash);
417 if (likely(e)) {
418 /* TODO: keep queueing to old queue until it's empty? */
419 e->queue_index = queue_index;
420 e->updated = jiffies;
421 sock_rps_record_flow_hash(e->rps_rxhash);
422 } else {
423 spin_lock_bh(&tun->lock);
424 if (!tun_flow_find(head, rxhash) &&
425 tun->flow_count < MAX_TAP_FLOWS)
426 tun_flow_create(tun, head, rxhash, queue_index);
427
428 if (!timer_pending(&tun->flow_gc_timer))
429 mod_timer(&tun->flow_gc_timer,
430 round_jiffies_up(jiffies + delay));
431 spin_unlock_bh(&tun->lock);
432 }
433
434unlock:
435 rcu_read_unlock();
436}
437
438/**
439 * Save the hash received in the stack receive path and update the
440 * flow_hash table accordingly.
441 */
442static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
443{
444 if (unlikely(e->rps_rxhash != hash))
445 e->rps_rxhash = hash;
446}
447
448/* We try to identify a flow through its rxhash first. The reason that
449 * we do not check rxq no. is because some cards(e.g 82599), chooses
450 * the rxq based on the txq where the last packet of the flow comes. As
451 * the userspace application move between processors, we may get a
452 * different rxq no. here. If we could not get rxhash, then we would
453 * hope the rxq no. may help here.
454 */
455static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
456 void *accel_priv, select_queue_fallback_t fallback)
457{
458 struct tun_struct *tun = netdev_priv(dev);
459 struct tun_flow_entry *e;
460 u32 txq = 0;
461 u32 numqueues = 0;
462
463 rcu_read_lock();
464 numqueues = ACCESS_ONCE(tun->numqueues);
465
466 txq = skb_get_hash(skb);
467 if (txq) {
468 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
469 if (e) {
470 tun_flow_save_rps_rxhash(e, txq);
471 txq = e->queue_index;
472 } else
473 /* use multiply and shift instead of expensive divide */
474 txq = ((u64)txq * numqueues) >> 32;
475 } else if (likely(skb_rx_queue_recorded(skb))) {
476 txq = skb_get_rx_queue(skb);
477 while (unlikely(txq >= numqueues))
478 txq -= numqueues;
479 }
480
481 rcu_read_unlock();
482 return txq;
483}
484
485static inline bool tun_not_capable(struct tun_struct *tun)
486{
487 const struct cred *cred = current_cred();
488 struct net *net = dev_net(tun->dev);
489
490 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
491 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
492 !ns_capable(net->user_ns, CAP_NET_ADMIN);
493}
494
495static void tun_set_real_num_queues(struct tun_struct *tun)
496{
497 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
498 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
499}
500
501static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
502{
503 tfile->detached = tun;
504 list_add_tail(&tfile->next, &tun->disabled);
505 ++tun->numdisabled;
506}
507
508static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
509{
510 struct tun_struct *tun = tfile->detached;
511
512 tfile->detached = NULL;
513 list_del_init(&tfile->next);
514 --tun->numdisabled;
515 return tun;
516}
517
518static void tun_queue_purge(struct tun_file *tfile)
519{
520 struct sk_buff *skb;
521
522 while ((skb = skb_array_consume(&tfile->tx_array)) != NULL)
523 kfree_skb(skb);
524
525 skb_queue_purge(&tfile->sk.sk_error_queue);
526}
527
528static void __tun_detach(struct tun_file *tfile, bool clean)
529{
530 struct tun_file *ntfile;
531 struct tun_struct *tun;
532
533 tun = rtnl_dereference(tfile->tun);
534
535 if (tun && !tfile->detached) {
536 u16 index = tfile->queue_index;
537 BUG_ON(index >= tun->numqueues);
538
539 rcu_assign_pointer(tun->tfiles[index],
540 tun->tfiles[tun->numqueues - 1]);
541 ntfile = rtnl_dereference(tun->tfiles[index]);
542 ntfile->queue_index = index;
543
544 --tun->numqueues;
545 if (clean) {
546 RCU_INIT_POINTER(tfile->tun, NULL);
547 sock_put(&tfile->sk);
548 } else
549 tun_disable_queue(tun, tfile);
550
551 synchronize_net();
552 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
553 /* Drop read queue */
554 tun_queue_purge(tfile);
555 tun_set_real_num_queues(tun);
556 } else if (tfile->detached && clean) {
557 tun = tun_enable_queue(tfile);
558 sock_put(&tfile->sk);
559 }
560
561 if (clean) {
562 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
563 netif_carrier_off(tun->dev);
564
565 if (!(tun->flags & IFF_PERSIST) &&
566 tun->dev->reg_state == NETREG_REGISTERED)
567 unregister_netdevice(tun->dev);
568 }
569 if (tun)
570 skb_array_cleanup(&tfile->tx_array);
571 sock_put(&tfile->sk);
572 }
573}
574
575static void tun_detach(struct tun_file *tfile, bool clean)
576{
577 rtnl_lock();
578 __tun_detach(tfile, clean);
579 rtnl_unlock();
580}
581
582static void tun_detach_all(struct net_device *dev)
583{
584 struct tun_struct *tun = netdev_priv(dev);
585 struct tun_file *tfile, *tmp;
586 int i, n = tun->numqueues;
587
588 for (i = 0; i < n; i++) {
589 tfile = rtnl_dereference(tun->tfiles[i]);
590 BUG_ON(!tfile);
591 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
592 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
593 RCU_INIT_POINTER(tfile->tun, NULL);
594 --tun->numqueues;
595 }
596 list_for_each_entry(tfile, &tun->disabled, next) {
597 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
598 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
599 RCU_INIT_POINTER(tfile->tun, NULL);
600 }
601 BUG_ON(tun->numqueues != 0);
602
603 synchronize_net();
604 for (i = 0; i < n; i++) {
605 tfile = rtnl_dereference(tun->tfiles[i]);
606 /* Drop read queue */
607 tun_queue_purge(tfile);
608 sock_put(&tfile->sk);
609 }
610 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
611 tun_enable_queue(tfile);
612 tun_queue_purge(tfile);
613 sock_put(&tfile->sk);
614 }
615 BUG_ON(tun->numdisabled != 0);
616
617 if (tun->flags & IFF_PERSIST)
618 module_put(THIS_MODULE);
619}
620
621static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
622{
623 struct tun_file *tfile = file->private_data;
624 struct net_device *dev = tun->dev;
625 int err;
626
627 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
628 if (err < 0)
629 goto out;
630
631 err = -EINVAL;
632 if (rtnl_dereference(tfile->tun) && !tfile->detached)
633 goto out;
634
635 err = -EBUSY;
636 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
637 goto out;
638
639 err = -E2BIG;
640 if (!tfile->detached &&
641 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
642 goto out;
643
644 err = 0;
645
646 /* Re-attach the filter to persist device */
647 if (!skip_filter && (tun->filter_attached == true)) {
648 lock_sock(tfile->socket.sk);
649 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
650 release_sock(tfile->socket.sk);
651 if (!err)
652 goto out;
653 }
654
655 if (!tfile->detached &&
656 skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL)) {
657 err = -ENOMEM;
658 goto out;
659 }
660
661 tfile->queue_index = tun->numqueues;
662 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
663 rcu_assign_pointer(tfile->tun, tun);
664 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
665 tun->numqueues++;
666
667 if (tfile->detached)
668 tun_enable_queue(tfile);
669 else
670 sock_hold(&tfile->sk);
671
672 tun_set_real_num_queues(tun);
673
674 /* device is allowed to go away first, so no need to hold extra
675 * refcnt.
676 */
677
678out:
679 return err;
680}
681
682static struct tun_struct *__tun_get(struct tun_file *tfile)
683{
684 struct tun_struct *tun;
685
686 rcu_read_lock();
687 tun = rcu_dereference(tfile->tun);
688 if (tun)
689 dev_hold(tun->dev);
690 rcu_read_unlock();
691
692 return tun;
693}
694
695static struct tun_struct *tun_get(struct file *file)
696{
697 return __tun_get(file->private_data);
698}
699
700static void tun_put(struct tun_struct *tun)
701{
702 dev_put(tun->dev);
703}
704
705/* TAP filtering */
706static void addr_hash_set(u32 *mask, const u8 *addr)
707{
708 int n = ether_crc(ETH_ALEN, addr) >> 26;
709 mask[n >> 5] |= (1 << (n & 31));
710}
711
712static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
713{
714 int n = ether_crc(ETH_ALEN, addr) >> 26;
715 return mask[n >> 5] & (1 << (n & 31));
716}
717
718static int update_filter(struct tap_filter *filter, void __user *arg)
719{
720 struct { u8 u[ETH_ALEN]; } *addr;
721 struct tun_filter uf;
722 int err, alen, n, nexact;
723
724 if (copy_from_user(&uf, arg, sizeof(uf)))
725 return -EFAULT;
726
727 if (!uf.count) {
728 /* Disabled */
729 filter->count = 0;
730 return 0;
731 }
732
733 alen = ETH_ALEN * uf.count;
734 addr = memdup_user(arg + sizeof(uf), alen);
735 if (IS_ERR(addr))
736 return PTR_ERR(addr);
737
738 /* The filter is updated without holding any locks. Which is
739 * perfectly safe. We disable it first and in the worst
740 * case we'll accept a few undesired packets. */
741 filter->count = 0;
742 wmb();
743
744 /* Use first set of addresses as an exact filter */
745 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
746 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
747
748 nexact = n;
749
750 /* Remaining multicast addresses are hashed,
751 * unicast will leave the filter disabled. */
752 memset(filter->mask, 0, sizeof(filter->mask));
753 for (; n < uf.count; n++) {
754 if (!is_multicast_ether_addr(addr[n].u)) {
755 err = 0; /* no filter */
756 goto free_addr;
757 }
758 addr_hash_set(filter->mask, addr[n].u);
759 }
760
761 /* For ALLMULTI just set the mask to all ones.
762 * This overrides the mask populated above. */
763 if ((uf.flags & TUN_FLT_ALLMULTI))
764 memset(filter->mask, ~0, sizeof(filter->mask));
765
766 /* Now enable the filter */
767 wmb();
768 filter->count = nexact;
769
770 /* Return the number of exact filters */
771 err = nexact;
772free_addr:
773 kfree(addr);
774 return err;
775}
776
777/* Returns: 0 - drop, !=0 - accept */
778static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
779{
780 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
781 * at this point. */
782 struct ethhdr *eh = (struct ethhdr *) skb->data;
783 int i;
784
785 /* Exact match */
786 for (i = 0; i < filter->count; i++)
787 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
788 return 1;
789
790 /* Inexact match (multicast only) */
791 if (is_multicast_ether_addr(eh->h_dest))
792 return addr_hash_test(filter->mask, eh->h_dest);
793
794 return 0;
795}
796
797/*
798 * Checks whether the packet is accepted or not.
799 * Returns: 0 - drop, !=0 - accept
800 */
801static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
802{
803 if (!filter->count)
804 return 1;
805
806 return run_filter(filter, skb);
807}
808
809/* Network device part of the driver */
810
811static const struct ethtool_ops tun_ethtool_ops;
812
813/* Net device detach from fd. */
814static void tun_net_uninit(struct net_device *dev)
815{
816 tun_detach_all(dev);
817}
818
819/* Net device open. */
820static int tun_net_open(struct net_device *dev)
821{
822 struct tun_struct *tun = netdev_priv(dev);
823 int i;
824
825 netif_tx_start_all_queues(dev);
826
827 for (i = 0; i < tun->numqueues; i++) {
828 struct tun_file *tfile;
829
830 tfile = rtnl_dereference(tun->tfiles[i]);
831 tfile->socket.sk->sk_write_space(tfile->socket.sk);
832 }
833
834 return 0;
835}
836
837/* Net device close. */
838static int tun_net_close(struct net_device *dev)
839{
840 netif_tx_stop_all_queues(dev);
841 return 0;
842}
843
844/* Net device start xmit */
845static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
846{
847 struct tun_struct *tun = netdev_priv(dev);
848 int txq = skb->queue_mapping;
849 struct tun_file *tfile;
850 u32 numqueues = 0;
851
852 rcu_read_lock();
853 tfile = rcu_dereference(tun->tfiles[txq]);
854 numqueues = ACCESS_ONCE(tun->numqueues);
855
856 /* Drop packet if interface is not attached */
857 if (txq >= numqueues)
858 goto drop;
859
860#ifdef CONFIG_RPS
861 if (numqueues == 1 && static_key_false(&rps_needed)) {
862 /* Select queue was not called for the skbuff, so we extract the
863 * RPS hash and save it into the flow_table here.
864 */
865 __u32 rxhash;
866
867 rxhash = skb_get_hash(skb);
868 if (rxhash) {
869 struct tun_flow_entry *e;
870 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
871 rxhash);
872 if (e)
873 tun_flow_save_rps_rxhash(e, rxhash);
874 }
875 }
876#endif
877
878 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
879
880 BUG_ON(!tfile);
881
882 /* Drop if the filter does not like it.
883 * This is a noop if the filter is disabled.
884 * Filter can be enabled only for the TAP devices. */
885 if (!check_filter(&tun->txflt, skb))
886 goto drop;
887
888 if (tfile->socket.sk->sk_filter &&
889 sk_filter(tfile->socket.sk, skb))
890 goto drop;
891
892 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
893 goto drop;
894
895 skb_tx_timestamp(skb);
896
897 /* Orphan the skb - required as we might hang on to it
898 * for indefinite time.
899 */
900 skb_orphan(skb);
901
902 nf_reset(skb);
903
904 if (skb_array_produce(&tfile->tx_array, skb))
905 goto drop;
906
907 /* Notify and wake up reader process */
908 if (tfile->flags & TUN_FASYNC)
909 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
910 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
911
912 rcu_read_unlock();
913 return NETDEV_TX_OK;
914
915drop:
916 this_cpu_inc(tun->pcpu_stats->tx_dropped);
917 skb_tx_error(skb);
918 kfree_skb(skb);
919 rcu_read_unlock();
920 return NET_XMIT_DROP;
921}
922
923static void tun_net_mclist(struct net_device *dev)
924{
925 /*
926 * This callback is supposed to deal with mc filter in
927 * _rx_ path and has nothing to do with the _tx_ path.
928 * In rx path we always accept everything userspace gives us.
929 */
930}
931
932static netdev_features_t tun_net_fix_features(struct net_device *dev,
933 netdev_features_t features)
934{
935 struct tun_struct *tun = netdev_priv(dev);
936
937 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
938}
939#ifdef CONFIG_NET_POLL_CONTROLLER
940static void tun_poll_controller(struct net_device *dev)
941{
942 /*
943 * Tun only receives frames when:
944 * 1) the char device endpoint gets data from user space
945 * 2) the tun socket gets a sendmsg call from user space
946 * Since both of those are synchronous operations, we are guaranteed
947 * never to have pending data when we poll for it
948 * so there is nothing to do here but return.
949 * We need this though so netpoll recognizes us as an interface that
950 * supports polling, which enables bridge devices in virt setups to
951 * still use netconsole
952 */
953 return;
954}
955#endif
956
957static void tun_set_headroom(struct net_device *dev, int new_hr)
958{
959 struct tun_struct *tun = netdev_priv(dev);
960
961 if (new_hr < NET_SKB_PAD)
962 new_hr = NET_SKB_PAD;
963
964 tun->align = new_hr;
965}
966
967static struct rtnl_link_stats64 *
968tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
969{
970 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
971 struct tun_struct *tun = netdev_priv(dev);
972 struct tun_pcpu_stats *p;
973 int i;
974
975 for_each_possible_cpu(i) {
976 u64 rxpackets, rxbytes, txpackets, txbytes;
977 unsigned int start;
978
979 p = per_cpu_ptr(tun->pcpu_stats, i);
980 do {
981 start = u64_stats_fetch_begin(&p->syncp);
982 rxpackets = p->rx_packets;
983 rxbytes = p->rx_bytes;
984 txpackets = p->tx_packets;
985 txbytes = p->tx_bytes;
986 } while (u64_stats_fetch_retry(&p->syncp, start));
987
988 stats->rx_packets += rxpackets;
989 stats->rx_bytes += rxbytes;
990 stats->tx_packets += txpackets;
991 stats->tx_bytes += txbytes;
992
993 /* u32 counters */
994 rx_dropped += p->rx_dropped;
995 rx_frame_errors += p->rx_frame_errors;
996 tx_dropped += p->tx_dropped;
997 }
998 stats->rx_dropped = rx_dropped;
999 stats->rx_frame_errors = rx_frame_errors;
1000 stats->tx_dropped = tx_dropped;
1001 return stats;
1002}
1003
1004static const struct net_device_ops tun_netdev_ops = {
1005 .ndo_uninit = tun_net_uninit,
1006 .ndo_open = tun_net_open,
1007 .ndo_stop = tun_net_close,
1008 .ndo_start_xmit = tun_net_xmit,
1009 .ndo_fix_features = tun_net_fix_features,
1010 .ndo_select_queue = tun_select_queue,
1011#ifdef CONFIG_NET_POLL_CONTROLLER
1012 .ndo_poll_controller = tun_poll_controller,
1013#endif
1014 .ndo_set_rx_headroom = tun_set_headroom,
1015 .ndo_get_stats64 = tun_net_get_stats64,
1016};
1017
1018static const struct net_device_ops tap_netdev_ops = {
1019 .ndo_uninit = tun_net_uninit,
1020 .ndo_open = tun_net_open,
1021 .ndo_stop = tun_net_close,
1022 .ndo_start_xmit = tun_net_xmit,
1023 .ndo_fix_features = tun_net_fix_features,
1024 .ndo_set_rx_mode = tun_net_mclist,
1025 .ndo_set_mac_address = eth_mac_addr,
1026 .ndo_validate_addr = eth_validate_addr,
1027 .ndo_select_queue = tun_select_queue,
1028#ifdef CONFIG_NET_POLL_CONTROLLER
1029 .ndo_poll_controller = tun_poll_controller,
1030#endif
1031 .ndo_features_check = passthru_features_check,
1032 .ndo_set_rx_headroom = tun_set_headroom,
1033 .ndo_get_stats64 = tun_net_get_stats64,
1034};
1035
1036static void tun_flow_init(struct tun_struct *tun)
1037{
1038 int i;
1039
1040 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1041 INIT_HLIST_HEAD(&tun->flows[i]);
1042
1043 tun->ageing_time = TUN_FLOW_EXPIRE;
1044 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
1045 mod_timer(&tun->flow_gc_timer,
1046 round_jiffies_up(jiffies + tun->ageing_time));
1047}
1048
1049static void tun_flow_uninit(struct tun_struct *tun)
1050{
1051 del_timer_sync(&tun->flow_gc_timer);
1052 tun_flow_flush(tun);
1053}
1054
1055#define MIN_MTU 68
1056#define MAX_MTU 65535
1057
1058/* Initialize net device. */
1059static void tun_net_init(struct net_device *dev)
1060{
1061 struct tun_struct *tun = netdev_priv(dev);
1062
1063 switch (tun->flags & TUN_TYPE_MASK) {
1064 case IFF_TUN:
1065 dev->netdev_ops = &tun_netdev_ops;
1066
1067 /* Point-to-Point TUN Device */
1068 dev->hard_header_len = 0;
1069 dev->addr_len = 0;
1070 dev->mtu = 1500;
1071
1072 /* Zero header length */
1073 dev->type = ARPHRD_NONE;
1074 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1075 break;
1076
1077 case IFF_TAP:
1078 dev->netdev_ops = &tap_netdev_ops;
1079 /* Ethernet TAP Device */
1080 ether_setup(dev);
1081 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1082 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1083
1084 eth_hw_addr_random(dev);
1085
1086 break;
1087 }
1088
1089 dev->min_mtu = MIN_MTU;
1090 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1091}
1092
1093/* Character device part */
1094
1095/* Poll */
1096static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1097{
1098 struct tun_file *tfile = file->private_data;
1099 struct tun_struct *tun = __tun_get(tfile);
1100 struct sock *sk;
1101 unsigned int mask = 0;
1102
1103 if (!tun)
1104 return POLLERR;
1105
1106 sk = tfile->socket.sk;
1107
1108 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1109
1110 poll_wait(file, sk_sleep(sk), wait);
1111
1112 if (!skb_array_empty(&tfile->tx_array))
1113 mask |= POLLIN | POLLRDNORM;
1114
1115 if (tun->dev->flags & IFF_UP &&
1116 (sock_writeable(sk) ||
1117 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1118 sock_writeable(sk))))
1119 mask |= POLLOUT | POLLWRNORM;
1120
1121 if (tun->dev->reg_state != NETREG_REGISTERED)
1122 mask = POLLERR;
1123
1124 tun_put(tun);
1125 return mask;
1126}
1127
1128/* prepad is the amount to reserve at front. len is length after that.
1129 * linear is a hint as to how much to copy (usually headers). */
1130static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1131 size_t prepad, size_t len,
1132 size_t linear, int noblock)
1133{
1134 struct sock *sk = tfile->socket.sk;
1135 struct sk_buff *skb;
1136 int err;
1137
1138 /* Under a page? Don't bother with paged skb. */
1139 if (prepad + len < PAGE_SIZE || !linear)
1140 linear = len;
1141
1142 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1143 &err, 0);
1144 if (!skb)
1145 return ERR_PTR(err);
1146
1147 skb_reserve(skb, prepad);
1148 skb_put(skb, linear);
1149 skb->data_len = len - linear;
1150 skb->len += len - linear;
1151
1152 return skb;
1153}
1154
1155/* Get packet from user space buffer */
1156static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1157 void *msg_control, struct iov_iter *from,
1158 int noblock)
1159{
1160 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1161 struct sk_buff *skb;
1162 size_t total_len = iov_iter_count(from);
1163 size_t len = total_len, align = tun->align, linear;
1164 struct virtio_net_hdr gso = { 0 };
1165 struct tun_pcpu_stats *stats;
1166 int good_linear;
1167 int copylen;
1168 bool zerocopy = false;
1169 int err;
1170 u32 rxhash;
1171
1172 if (!(tun->dev->flags & IFF_UP))
1173 return -EIO;
1174
1175 if (!(tun->flags & IFF_NO_PI)) {
1176 if (len < sizeof(pi))
1177 return -EINVAL;
1178 len -= sizeof(pi);
1179
1180 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1181 return -EFAULT;
1182 }
1183
1184 if (tun->flags & IFF_VNET_HDR) {
1185 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1186
1187 if (len < vnet_hdr_sz)
1188 return -EINVAL;
1189 len -= vnet_hdr_sz;
1190
1191 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1192 return -EFAULT;
1193
1194 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1195 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1196 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1197
1198 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1199 return -EINVAL;
1200 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1201 }
1202
1203 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1204 align += NET_IP_ALIGN;
1205 if (unlikely(len < ETH_HLEN ||
1206 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1207 return -EINVAL;
1208 }
1209
1210 good_linear = SKB_MAX_HEAD(align);
1211
1212 if (msg_control) {
1213 struct iov_iter i = *from;
1214
1215 /* There are 256 bytes to be copied in skb, so there is
1216 * enough room for skb expand head in case it is used.
1217 * The rest of the buffer is mapped from userspace.
1218 */
1219 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1220 if (copylen > good_linear)
1221 copylen = good_linear;
1222 linear = copylen;
1223 iov_iter_advance(&i, copylen);
1224 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1225 zerocopy = true;
1226 }
1227
1228 if (!zerocopy) {
1229 copylen = len;
1230 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1231 linear = good_linear;
1232 else
1233 linear = tun16_to_cpu(tun, gso.hdr_len);
1234 }
1235
1236 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1237 if (IS_ERR(skb)) {
1238 if (PTR_ERR(skb) != -EAGAIN)
1239 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1240 return PTR_ERR(skb);
1241 }
1242
1243 if (zerocopy)
1244 err = zerocopy_sg_from_iter(skb, from);
1245 else
1246 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1247
1248 if (err) {
1249 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1250 kfree_skb(skb);
1251 return -EFAULT;
1252 }
1253
1254 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1255 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1256 kfree_skb(skb);
1257 return -EINVAL;
1258 }
1259
1260 switch (tun->flags & TUN_TYPE_MASK) {
1261 case IFF_TUN:
1262 if (tun->flags & IFF_NO_PI) {
1263 switch (skb->data[0] & 0xf0) {
1264 case 0x40:
1265 pi.proto = htons(ETH_P_IP);
1266 break;
1267 case 0x60:
1268 pi.proto = htons(ETH_P_IPV6);
1269 break;
1270 default:
1271 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1272 kfree_skb(skb);
1273 return -EINVAL;
1274 }
1275 }
1276
1277 skb_reset_mac_header(skb);
1278 skb->protocol = pi.proto;
1279 skb->dev = tun->dev;
1280 break;
1281 case IFF_TAP:
1282 skb->protocol = eth_type_trans(skb, tun->dev);
1283 break;
1284 }
1285
1286 /* copy skb_ubuf_info for callback when skb has no error */
1287 if (zerocopy) {
1288 skb_shinfo(skb)->destructor_arg = msg_control;
1289 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1290 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1291 } else if (msg_control) {
1292 struct ubuf_info *uarg = msg_control;
1293 uarg->callback(uarg, false);
1294 }
1295
1296 skb_reset_network_header(skb);
1297 skb_probe_transport_header(skb, 0);
1298
1299 rxhash = skb_get_hash(skb);
1300#ifndef CONFIG_4KSTACKS
1301 local_bh_disable();
1302 netif_receive_skb(skb);
1303 local_bh_enable();
1304#else
1305 netif_rx_ni(skb);
1306#endif
1307
1308 stats = get_cpu_ptr(tun->pcpu_stats);
1309 u64_stats_update_begin(&stats->syncp);
1310 stats->rx_packets++;
1311 stats->rx_bytes += len;
1312 u64_stats_update_end(&stats->syncp);
1313 put_cpu_ptr(stats);
1314
1315 tun_flow_update(tun, rxhash, tfile);
1316 return total_len;
1317}
1318
1319static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1320{
1321 struct file *file = iocb->ki_filp;
1322 struct tun_struct *tun = tun_get(file);
1323 struct tun_file *tfile = file->private_data;
1324 ssize_t result;
1325
1326 if (!tun)
1327 return -EBADFD;
1328
1329 result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);
1330
1331 tun_put(tun);
1332 return result;
1333}
1334
1335/* Put packet to the user space buffer */
1336static ssize_t tun_put_user(struct tun_struct *tun,
1337 struct tun_file *tfile,
1338 struct sk_buff *skb,
1339 struct iov_iter *iter)
1340{
1341 struct tun_pi pi = { 0, skb->protocol };
1342 struct tun_pcpu_stats *stats;
1343 ssize_t total;
1344 int vlan_offset = 0;
1345 int vlan_hlen = 0;
1346 int vnet_hdr_sz = 0;
1347
1348 if (skb_vlan_tag_present(skb))
1349 vlan_hlen = VLAN_HLEN;
1350
1351 if (tun->flags & IFF_VNET_HDR)
1352 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1353
1354 total = skb->len + vlan_hlen + vnet_hdr_sz;
1355
1356 if (!(tun->flags & IFF_NO_PI)) {
1357 if (iov_iter_count(iter) < sizeof(pi))
1358 return -EINVAL;
1359
1360 total += sizeof(pi);
1361 if (iov_iter_count(iter) < total) {
1362 /* Packet will be striped */
1363 pi.flags |= TUN_PKT_STRIP;
1364 }
1365
1366 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1367 return -EFAULT;
1368 }
1369
1370 if (vnet_hdr_sz) {
1371 struct virtio_net_hdr gso;
1372
1373 if (iov_iter_count(iter) < vnet_hdr_sz)
1374 return -EINVAL;
1375
1376 if (virtio_net_hdr_from_skb(skb, &gso,
1377 tun_is_little_endian(tun), true)) {
1378 struct skb_shared_info *sinfo = skb_shinfo(skb);
1379 pr_err("unexpected GSO type: "
1380 "0x%x, gso_size %d, hdr_len %d\n",
1381 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1382 tun16_to_cpu(tun, gso.hdr_len));
1383 print_hex_dump(KERN_ERR, "tun: ",
1384 DUMP_PREFIX_NONE,
1385 16, 1, skb->head,
1386 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1387 WARN_ON_ONCE(1);
1388 return -EINVAL;
1389 }
1390
1391 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1392 return -EFAULT;
1393
1394 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1395 }
1396
1397 if (vlan_hlen) {
1398 int ret;
1399 struct {
1400 __be16 h_vlan_proto;
1401 __be16 h_vlan_TCI;
1402 } veth;
1403
1404 veth.h_vlan_proto = skb->vlan_proto;
1405 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1406
1407 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1408
1409 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1410 if (ret || !iov_iter_count(iter))
1411 goto done;
1412
1413 ret = copy_to_iter(&veth, sizeof(veth), iter);
1414 if (ret != sizeof(veth) || !iov_iter_count(iter))
1415 goto done;
1416 }
1417
1418 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1419
1420done:
1421 /* caller is in process context, */
1422 stats = get_cpu_ptr(tun->pcpu_stats);
1423 u64_stats_update_begin(&stats->syncp);
1424 stats->tx_packets++;
1425 stats->tx_bytes += skb->len + vlan_hlen;
1426 u64_stats_update_end(&stats->syncp);
1427 put_cpu_ptr(tun->pcpu_stats);
1428
1429 return total;
1430}
1431
1432static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
1433 int *err)
1434{
1435 DECLARE_WAITQUEUE(wait, current);
1436 struct sk_buff *skb = NULL;
1437 int error = 0;
1438
1439 skb = skb_array_consume(&tfile->tx_array);
1440 if (skb)
1441 goto out;
1442 if (noblock) {
1443 error = -EAGAIN;
1444 goto out;
1445 }
1446
1447 add_wait_queue(&tfile->wq.wait, &wait);
1448 current->state = TASK_INTERRUPTIBLE;
1449
1450 while (1) {
1451 skb = skb_array_consume(&tfile->tx_array);
1452 if (skb)
1453 break;
1454 if (signal_pending(current)) {
1455 error = -ERESTARTSYS;
1456 break;
1457 }
1458 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
1459 error = -EFAULT;
1460 break;
1461 }
1462
1463 schedule();
1464 }
1465
1466 current->state = TASK_RUNNING;
1467 remove_wait_queue(&tfile->wq.wait, &wait);
1468
1469out:
1470 *err = error;
1471 return skb;
1472}
1473
1474static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1475 struct iov_iter *to,
1476 int noblock)
1477{
1478 struct sk_buff *skb;
1479 ssize_t ret;
1480 int err;
1481
1482 tun_debug(KERN_INFO, tun, "tun_do_read\n");
1483
1484 if (!iov_iter_count(to))
1485 return 0;
1486
1487 /* Read frames from ring */
1488 skb = tun_ring_recv(tfile, noblock, &err);
1489 if (!skb)
1490 return err;
1491
1492 ret = tun_put_user(tun, tfile, skb, to);
1493 if (unlikely(ret < 0))
1494 kfree_skb(skb);
1495 else
1496 consume_skb(skb);
1497
1498 return ret;
1499}
1500
1501static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1502{
1503 struct file *file = iocb->ki_filp;
1504 struct tun_file *tfile = file->private_data;
1505 struct tun_struct *tun = __tun_get(tfile);
1506 ssize_t len = iov_iter_count(to), ret;
1507
1508 if (!tun)
1509 return -EBADFD;
1510 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
1511 ret = min_t(ssize_t, ret, len);
1512 if (ret > 0)
1513 iocb->ki_pos = ret;
1514 tun_put(tun);
1515 return ret;
1516}
1517
1518static void tun_free_netdev(struct net_device *dev)
1519{
1520 struct tun_struct *tun = netdev_priv(dev);
1521
1522 BUG_ON(!(list_empty(&tun->disabled)));
1523 free_percpu(tun->pcpu_stats);
1524 tun_flow_uninit(tun);
1525 security_tun_dev_free_security(tun->security);
1526 free_netdev(dev);
1527}
1528
1529static void tun_setup(struct net_device *dev)
1530{
1531 struct tun_struct *tun = netdev_priv(dev);
1532
1533 tun->owner = INVALID_UID;
1534 tun->group = INVALID_GID;
1535
1536 dev->ethtool_ops = &tun_ethtool_ops;
1537 dev->destructor = tun_free_netdev;
1538 /* We prefer our own queue length */
1539 dev->tx_queue_len = TUN_READQ_SIZE;
1540}
1541
1542/* Trivial set of netlink ops to allow deleting tun or tap
1543 * device with netlink.
1544 */
1545static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1546{
1547 return -EINVAL;
1548}
1549
1550static struct rtnl_link_ops tun_link_ops __read_mostly = {
1551 .kind = DRV_NAME,
1552 .priv_size = sizeof(struct tun_struct),
1553 .setup = tun_setup,
1554 .validate = tun_validate,
1555};
1556
1557static void tun_sock_write_space(struct sock *sk)
1558{
1559 struct tun_file *tfile;
1560 wait_queue_head_t *wqueue;
1561
1562 if (!sock_writeable(sk))
1563 return;
1564
1565 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
1566 return;
1567
1568 wqueue = sk_sleep(sk);
1569 if (wqueue && waitqueue_active(wqueue))
1570 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1571 POLLWRNORM | POLLWRBAND);
1572
1573 tfile = container_of(sk, struct tun_file, sk);
1574 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1575}
1576
1577static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1578{
1579 int ret;
1580 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1581 struct tun_struct *tun = __tun_get(tfile);
1582
1583 if (!tun)
1584 return -EBADFD;
1585
1586 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1587 m->msg_flags & MSG_DONTWAIT);
1588 tun_put(tun);
1589 return ret;
1590}
1591
1592static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1593 int flags)
1594{
1595 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1596 struct tun_struct *tun = __tun_get(tfile);
1597 int ret;
1598
1599 if (!tun)
1600 return -EBADFD;
1601
1602 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1603 ret = -EINVAL;
1604 goto out;
1605 }
1606 if (flags & MSG_ERRQUEUE) {
1607 ret = sock_recv_errqueue(sock->sk, m, total_len,
1608 SOL_PACKET, TUN_TX_TIMESTAMP);
1609 goto out;
1610 }
1611 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1612 if (ret > (ssize_t)total_len) {
1613 m->msg_flags |= MSG_TRUNC;
1614 ret = flags & MSG_TRUNC ? ret : total_len;
1615 }
1616out:
1617 tun_put(tun);
1618 return ret;
1619}
1620
1621static int tun_peek_len(struct socket *sock)
1622{
1623 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1624 struct tun_struct *tun;
1625 int ret = 0;
1626
1627 tun = __tun_get(tfile);
1628 if (!tun)
1629 return 0;
1630
1631 ret = skb_array_peek_len(&tfile->tx_array);
1632 tun_put(tun);
1633
1634 return ret;
1635}
1636
1637/* Ops structure to mimic raw sockets with tun */
1638static const struct proto_ops tun_socket_ops = {
1639 .peek_len = tun_peek_len,
1640 .sendmsg = tun_sendmsg,
1641 .recvmsg = tun_recvmsg,
1642};
1643
1644static struct proto tun_proto = {
1645 .name = "tun",
1646 .owner = THIS_MODULE,
1647 .obj_size = sizeof(struct tun_file),
1648};
1649
1650static int tun_flags(struct tun_struct *tun)
1651{
1652 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1653}
1654
1655static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1656 char *buf)
1657{
1658 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1659 return sprintf(buf, "0x%x\n", tun_flags(tun));
1660}
1661
1662static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1663 char *buf)
1664{
1665 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1666 return uid_valid(tun->owner)?
1667 sprintf(buf, "%u\n",
1668 from_kuid_munged(current_user_ns(), tun->owner)):
1669 sprintf(buf, "-1\n");
1670}
1671
1672static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1673 char *buf)
1674{
1675 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1676 return gid_valid(tun->group) ?
1677 sprintf(buf, "%u\n",
1678 from_kgid_munged(current_user_ns(), tun->group)):
1679 sprintf(buf, "-1\n");
1680}
1681
1682static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1683static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1684static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1685
1686static struct attribute *tun_dev_attrs[] = {
1687 &dev_attr_tun_flags.attr,
1688 &dev_attr_owner.attr,
1689 &dev_attr_group.attr,
1690 NULL
1691};
1692
1693static const struct attribute_group tun_attr_group = {
1694 .attrs = tun_dev_attrs
1695};
1696
1697static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1698{
1699 struct tun_struct *tun;
1700 struct tun_file *tfile = file->private_data;
1701 struct net_device *dev;
1702 int err;
1703
1704 if (tfile->detached)
1705 return -EINVAL;
1706
1707 dev = __dev_get_by_name(net, ifr->ifr_name);
1708 if (dev) {
1709 if (ifr->ifr_flags & IFF_TUN_EXCL)
1710 return -EBUSY;
1711 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1712 tun = netdev_priv(dev);
1713 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1714 tun = netdev_priv(dev);
1715 else
1716 return -EINVAL;
1717
1718 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1719 !!(tun->flags & IFF_MULTI_QUEUE))
1720 return -EINVAL;
1721
1722 if (tun_not_capable(tun))
1723 return -EPERM;
1724 err = security_tun_dev_open(tun->security);
1725 if (err < 0)
1726 return err;
1727
1728 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1729 if (err < 0)
1730 return err;
1731
1732 if (tun->flags & IFF_MULTI_QUEUE &&
1733 (tun->numqueues + tun->numdisabled > 1)) {
1734 /* One or more queue has already been attached, no need
1735 * to initialize the device again.
1736 */
1737 return 0;
1738 }
1739 }
1740 else {
1741 char *name;
1742 unsigned long flags = 0;
1743 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1744 MAX_TAP_QUEUES : 1;
1745
1746 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1747 return -EPERM;
1748 err = security_tun_dev_create();
1749 if (err < 0)
1750 return err;
1751
1752 /* Set dev type */
1753 if (ifr->ifr_flags & IFF_TUN) {
1754 /* TUN device */
1755 flags |= IFF_TUN;
1756 name = "tun%d";
1757 } else if (ifr->ifr_flags & IFF_TAP) {
1758 /* TAP device */
1759 flags |= IFF_TAP;
1760 name = "tap%d";
1761 } else
1762 return -EINVAL;
1763
1764 if (*ifr->ifr_name)
1765 name = ifr->ifr_name;
1766
1767 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1768 NET_NAME_UNKNOWN, tun_setup, queues,
1769 queues);
1770
1771 if (!dev)
1772 return -ENOMEM;
1773
1774 dev_net_set(dev, net);
1775 dev->rtnl_link_ops = &tun_link_ops;
1776 dev->ifindex = tfile->ifindex;
1777 dev->sysfs_groups[0] = &tun_attr_group;
1778
1779 tun = netdev_priv(dev);
1780 tun->dev = dev;
1781 tun->flags = flags;
1782 tun->txflt.count = 0;
1783 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1784
1785 tun->align = NET_SKB_PAD;
1786 tun->filter_attached = false;
1787 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1788
1789 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
1790 if (!tun->pcpu_stats) {
1791 err = -ENOMEM;
1792 goto err_free_dev;
1793 }
1794
1795 spin_lock_init(&tun->lock);
1796
1797 err = security_tun_dev_alloc_security(&tun->security);
1798 if (err < 0)
1799 goto err_free_stat;
1800
1801 tun_net_init(dev);
1802 tun_flow_init(tun);
1803
1804 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1805 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1806 NETIF_F_HW_VLAN_STAG_TX;
1807 dev->features = dev->hw_features | NETIF_F_LLTX;
1808 dev->vlan_features = dev->features &
1809 ~(NETIF_F_HW_VLAN_CTAG_TX |
1810 NETIF_F_HW_VLAN_STAG_TX);
1811
1812 INIT_LIST_HEAD(&tun->disabled);
1813 err = tun_attach(tun, file, false);
1814 if (err < 0)
1815 goto err_free_flow;
1816
1817 err = register_netdevice(tun->dev);
1818 if (err < 0)
1819 goto err_detach;
1820 }
1821
1822 netif_carrier_on(tun->dev);
1823
1824 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1825
1826 tun->flags = (tun->flags & ~TUN_FEATURES) |
1827 (ifr->ifr_flags & TUN_FEATURES);
1828
1829 /* Make sure persistent devices do not get stuck in
1830 * xoff state.
1831 */
1832 if (netif_running(tun->dev))
1833 netif_tx_wake_all_queues(tun->dev);
1834
1835 strcpy(ifr->ifr_name, tun->dev->name);
1836 return 0;
1837
1838err_detach:
1839 tun_detach_all(dev);
1840err_free_flow:
1841 tun_flow_uninit(tun);
1842 security_tun_dev_free_security(tun->security);
1843err_free_stat:
1844 free_percpu(tun->pcpu_stats);
1845err_free_dev:
1846 free_netdev(dev);
1847 return err;
1848}
1849
1850static void tun_get_iff(struct net *net, struct tun_struct *tun,
1851 struct ifreq *ifr)
1852{
1853 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1854
1855 strcpy(ifr->ifr_name, tun->dev->name);
1856
1857 ifr->ifr_flags = tun_flags(tun);
1858
1859}
1860
1861/* This is like a cut-down ethtool ops, except done via tun fd so no
1862 * privs required. */
1863static int set_offload(struct tun_struct *tun, unsigned long arg)
1864{
1865 netdev_features_t features = 0;
1866
1867 if (arg & TUN_F_CSUM) {
1868 features |= NETIF_F_HW_CSUM;
1869 arg &= ~TUN_F_CSUM;
1870
1871 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1872 if (arg & TUN_F_TSO_ECN) {
1873 features |= NETIF_F_TSO_ECN;
1874 arg &= ~TUN_F_TSO_ECN;
1875 }
1876 if (arg & TUN_F_TSO4)
1877 features |= NETIF_F_TSO;
1878 if (arg & TUN_F_TSO6)
1879 features |= NETIF_F_TSO6;
1880 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1881 }
1882
1883 if (arg & TUN_F_UFO) {
1884 features |= NETIF_F_UFO;
1885 arg &= ~TUN_F_UFO;
1886 }
1887 }
1888
1889 /* This gives the user a way to test for new features in future by
1890 * trying to set them. */
1891 if (arg)
1892 return -EINVAL;
1893
1894 tun->set_features = features;
1895 netdev_update_features(tun->dev);
1896
1897 return 0;
1898}
1899
1900static void tun_detach_filter(struct tun_struct *tun, int n)
1901{
1902 int i;
1903 struct tun_file *tfile;
1904
1905 for (i = 0; i < n; i++) {
1906 tfile = rtnl_dereference(tun->tfiles[i]);
1907 lock_sock(tfile->socket.sk);
1908 sk_detach_filter(tfile->socket.sk);
1909 release_sock(tfile->socket.sk);
1910 }
1911
1912 tun->filter_attached = false;
1913}
1914
1915static int tun_attach_filter(struct tun_struct *tun)
1916{
1917 int i, ret = 0;
1918 struct tun_file *tfile;
1919
1920 for (i = 0; i < tun->numqueues; i++) {
1921 tfile = rtnl_dereference(tun->tfiles[i]);
1922 lock_sock(tfile->socket.sk);
1923 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1924 release_sock(tfile->socket.sk);
1925 if (ret) {
1926 tun_detach_filter(tun, i);
1927 return ret;
1928 }
1929 }
1930
1931 tun->filter_attached = true;
1932 return ret;
1933}
1934
1935static void tun_set_sndbuf(struct tun_struct *tun)
1936{
1937 struct tun_file *tfile;
1938 int i;
1939
1940 for (i = 0; i < tun->numqueues; i++) {
1941 tfile = rtnl_dereference(tun->tfiles[i]);
1942 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1943 }
1944}
1945
1946static int tun_set_queue(struct file *file, struct ifreq *ifr)
1947{
1948 struct tun_file *tfile = file->private_data;
1949 struct tun_struct *tun;
1950 int ret = 0;
1951
1952 rtnl_lock();
1953
1954 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1955 tun = tfile->detached;
1956 if (!tun) {
1957 ret = -EINVAL;
1958 goto unlock;
1959 }
1960 ret = security_tun_dev_attach_queue(tun->security);
1961 if (ret < 0)
1962 goto unlock;
1963 ret = tun_attach(tun, file, false);
1964 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1965 tun = rtnl_dereference(tfile->tun);
1966 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1967 ret = -EINVAL;
1968 else
1969 __tun_detach(tfile, false);
1970 } else
1971 ret = -EINVAL;
1972
1973unlock:
1974 rtnl_unlock();
1975 return ret;
1976}
1977
1978static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1979 unsigned long arg, int ifreq_len)
1980{
1981 struct tun_file *tfile = file->private_data;
1982 struct tun_struct *tun;
1983 void __user* argp = (void __user*)arg;
1984 struct ifreq ifr;
1985 kuid_t owner;
1986 kgid_t group;
1987 int sndbuf;
1988 int vnet_hdr_sz;
1989 unsigned int ifindex;
1990 int le;
1991 int ret;
1992
1993 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) {
1994 if (copy_from_user(&ifr, argp, ifreq_len))
1995 return -EFAULT;
1996 } else {
1997 memset(&ifr, 0, sizeof(ifr));
1998 }
1999 if (cmd == TUNGETFEATURES) {
2000 /* Currently this just means: "what IFF flags are valid?".
2001 * This is needed because we never checked for invalid flags on
2002 * TUNSETIFF.
2003 */
2004 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2005 (unsigned int __user*)argp);
2006 } else if (cmd == TUNSETQUEUE)
2007 return tun_set_queue(file, &ifr);
2008
2009 ret = 0;
2010 rtnl_lock();
2011
2012 tun = __tun_get(tfile);
2013 if (cmd == TUNSETIFF) {
2014 ret = -EEXIST;
2015 if (tun)
2016 goto unlock;
2017
2018 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2019
2020 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
2021
2022 if (ret)
2023 goto unlock;
2024
2025 if (copy_to_user(argp, &ifr, ifreq_len))
2026 ret = -EFAULT;
2027 goto unlock;
2028 }
2029 if (cmd == TUNSETIFINDEX) {
2030 ret = -EPERM;
2031 if (tun)
2032 goto unlock;
2033
2034 ret = -EFAULT;
2035 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2036 goto unlock;
2037
2038 ret = 0;
2039 tfile->ifindex = ifindex;
2040 goto unlock;
2041 }
2042
2043 ret = -EBADFD;
2044 if (!tun)
2045 goto unlock;
2046
2047 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2048
2049 ret = 0;
2050 switch (cmd) {
2051 case TUNGETIFF:
2052 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2053
2054 if (tfile->detached)
2055 ifr.ifr_flags |= IFF_DETACH_QUEUE;
2056 if (!tfile->socket.sk->sk_filter)
2057 ifr.ifr_flags |= IFF_NOFILTER;
2058
2059 if (copy_to_user(argp, &ifr, ifreq_len))
2060 ret = -EFAULT;
2061 break;
2062
2063 case TUNSETNOCSUM:
2064 /* Disable/Enable checksum */
2065
2066 /* [unimplemented] */
2067 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2068 arg ? "disabled" : "enabled");
2069 break;
2070
2071 case TUNSETPERSIST:
2072 /* Disable/Enable persist mode. Keep an extra reference to the
2073 * module to prevent the module being unprobed.
2074 */
2075 if (arg && !(tun->flags & IFF_PERSIST)) {
2076 tun->flags |= IFF_PERSIST;
2077 __module_get(THIS_MODULE);
2078 }
2079 if (!arg && (tun->flags & IFF_PERSIST)) {
2080 tun->flags &= ~IFF_PERSIST;
2081 module_put(THIS_MODULE);
2082 }
2083
2084 tun_debug(KERN_INFO, tun, "persist %s\n",
2085 arg ? "enabled" : "disabled");
2086 break;
2087
2088 case TUNSETOWNER:
2089 /* Set owner of the device */
2090 owner = make_kuid(current_user_ns(), arg);
2091 if (!uid_valid(owner)) {
2092 ret = -EINVAL;
2093 break;
2094 }
2095 tun->owner = owner;
2096 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2097 from_kuid(&init_user_ns, tun->owner));
2098 break;
2099
2100 case TUNSETGROUP:
2101 /* Set group of the device */
2102 group = make_kgid(current_user_ns(), arg);
2103 if (!gid_valid(group)) {
2104 ret = -EINVAL;
2105 break;
2106 }
2107 tun->group = group;
2108 tun_debug(KERN_INFO, tun, "group set to %u\n",
2109 from_kgid(&init_user_ns, tun->group));
2110 break;
2111
2112 case TUNSETLINK:
2113 /* Only allow setting the type when the interface is down */
2114 if (tun->dev->flags & IFF_UP) {
2115 tun_debug(KERN_INFO, tun,
2116 "Linktype set failed because interface is up\n");
2117 ret = -EBUSY;
2118 } else {
2119 tun->dev->type = (int) arg;
2120 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2121 tun->dev->type);
2122 ret = 0;
2123 }
2124 break;
2125
2126#ifdef TUN_DEBUG
2127 case TUNSETDEBUG:
2128 tun->debug = arg;
2129 break;
2130#endif
2131 case TUNSETOFFLOAD:
2132 ret = set_offload(tun, arg);
2133 break;
2134
2135 case TUNSETTXFILTER:
2136 /* Can be set only for TAPs */
2137 ret = -EINVAL;
2138 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2139 break;
2140 ret = update_filter(&tun->txflt, (void __user *)arg);
2141 break;
2142
2143 case SIOCGIFHWADDR:
2144 /* Get hw address */
2145 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2146 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2147 if (copy_to_user(argp, &ifr, ifreq_len))
2148 ret = -EFAULT;
2149 break;
2150
2151 case SIOCSIFHWADDR:
2152 /* Set hw address */
2153 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2154 ifr.ifr_hwaddr.sa_data);
2155
2156 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2157 break;
2158
2159 case TUNGETSNDBUF:
2160 sndbuf = tfile->socket.sk->sk_sndbuf;
2161 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2162 ret = -EFAULT;
2163 break;
2164
2165 case TUNSETSNDBUF:
2166 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2167 ret = -EFAULT;
2168 break;
2169 }
2170
2171 tun->sndbuf = sndbuf;
2172 tun_set_sndbuf(tun);
2173 break;
2174
2175 case TUNGETVNETHDRSZ:
2176 vnet_hdr_sz = tun->vnet_hdr_sz;
2177 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2178 ret = -EFAULT;
2179 break;
2180
2181 case TUNSETVNETHDRSZ:
2182 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2183 ret = -EFAULT;
2184 break;
2185 }
2186 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2187 ret = -EINVAL;
2188 break;
2189 }
2190
2191 tun->vnet_hdr_sz = vnet_hdr_sz;
2192 break;
2193
2194 case TUNGETVNETLE:
2195 le = !!(tun->flags & TUN_VNET_LE);
2196 if (put_user(le, (int __user *)argp))
2197 ret = -EFAULT;
2198 break;
2199
2200 case TUNSETVNETLE:
2201 if (get_user(le, (int __user *)argp)) {
2202 ret = -EFAULT;
2203 break;
2204 }
2205 if (le)
2206 tun->flags |= TUN_VNET_LE;
2207 else
2208 tun->flags &= ~TUN_VNET_LE;
2209 break;
2210
2211 case TUNGETVNETBE:
2212 ret = tun_get_vnet_be(tun, argp);
2213 break;
2214
2215 case TUNSETVNETBE:
2216 ret = tun_set_vnet_be(tun, argp);
2217 break;
2218
2219 case TUNATTACHFILTER:
2220 /* Can be set only for TAPs */
2221 ret = -EINVAL;
2222 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2223 break;
2224 ret = -EFAULT;
2225 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2226 break;
2227
2228 ret = tun_attach_filter(tun);
2229 break;
2230
2231 case TUNDETACHFILTER:
2232 /* Can be set only for TAPs */
2233 ret = -EINVAL;
2234 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2235 break;
2236 ret = 0;
2237 tun_detach_filter(tun, tun->numqueues);
2238 break;
2239
2240 case TUNGETFILTER:
2241 ret = -EINVAL;
2242 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2243 break;
2244 ret = -EFAULT;
2245 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2246 break;
2247 ret = 0;
2248 break;
2249
2250 default:
2251 ret = -EINVAL;
2252 break;
2253 }
2254
2255unlock:
2256 rtnl_unlock();
2257 if (tun)
2258 tun_put(tun);
2259 return ret;
2260}
2261
2262static long tun_chr_ioctl(struct file *file,
2263 unsigned int cmd, unsigned long arg)
2264{
2265 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2266}
2267
2268#ifdef CONFIG_COMPAT
2269static long tun_chr_compat_ioctl(struct file *file,
2270 unsigned int cmd, unsigned long arg)
2271{
2272 switch (cmd) {
2273 case TUNSETIFF:
2274 case TUNGETIFF:
2275 case TUNSETTXFILTER:
2276 case TUNGETSNDBUF:
2277 case TUNSETSNDBUF:
2278 case SIOCGIFHWADDR:
2279 case SIOCSIFHWADDR:
2280 arg = (unsigned long)compat_ptr(arg);
2281 break;
2282 default:
2283 arg = (compat_ulong_t)arg;
2284 break;
2285 }
2286
2287 /*
2288 * compat_ifreq is shorter than ifreq, so we must not access beyond
2289 * the end of that structure. All fields that are used in this
2290 * driver are compatible though, we don't need to convert the
2291 * contents.
2292 */
2293 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2294}
2295#endif /* CONFIG_COMPAT */
2296
2297static int tun_chr_fasync(int fd, struct file *file, int on)
2298{
2299 struct tun_file *tfile = file->private_data;
2300 int ret;
2301
2302 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2303 goto out;
2304
2305 if (on) {
2306 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2307 tfile->flags |= TUN_FASYNC;
2308 } else
2309 tfile->flags &= ~TUN_FASYNC;
2310 ret = 0;
2311out:
2312 return ret;
2313}
2314
2315static int tun_chr_open(struct inode *inode, struct file * file)
2316{
2317 struct net *net = current->nsproxy->net_ns;
2318 struct tun_file *tfile;
2319
2320 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2321
2322 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2323 &tun_proto, 0);
2324 if (!tfile)
2325 return -ENOMEM;
2326 RCU_INIT_POINTER(tfile->tun, NULL);
2327 tfile->flags = 0;
2328 tfile->ifindex = 0;
2329
2330 init_waitqueue_head(&tfile->wq.wait);
2331 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2332
2333 tfile->socket.file = file;
2334 tfile->socket.ops = &tun_socket_ops;
2335
2336 sock_init_data(&tfile->socket, &tfile->sk);
2337
2338 tfile->sk.sk_write_space = tun_sock_write_space;
2339 tfile->sk.sk_sndbuf = INT_MAX;
2340
2341 file->private_data = tfile;
2342 INIT_LIST_HEAD(&tfile->next);
2343
2344 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2345
2346 return 0;
2347}
2348
2349static int tun_chr_close(struct inode *inode, struct file *file)
2350{
2351 struct tun_file *tfile = file->private_data;
2352
2353 tun_detach(tfile, true);
2354
2355 return 0;
2356}
2357
2358#ifdef CONFIG_PROC_FS
2359static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2360{
2361 struct tun_struct *tun;
2362 struct ifreq ifr;
2363
2364 memset(&ifr, 0, sizeof(ifr));
2365
2366 rtnl_lock();
2367 tun = tun_get(f);
2368 if (tun)
2369 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2370 rtnl_unlock();
2371
2372 if (tun)
2373 tun_put(tun);
2374
2375 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2376}
2377#endif
2378
2379static const struct file_operations tun_fops = {
2380 .owner = THIS_MODULE,
2381 .llseek = no_llseek,
2382 .read_iter = tun_chr_read_iter,
2383 .write_iter = tun_chr_write_iter,
2384 .poll = tun_chr_poll,
2385 .unlocked_ioctl = tun_chr_ioctl,
2386#ifdef CONFIG_COMPAT
2387 .compat_ioctl = tun_chr_compat_ioctl,
2388#endif
2389 .open = tun_chr_open,
2390 .release = tun_chr_close,
2391 .fasync = tun_chr_fasync,
2392#ifdef CONFIG_PROC_FS
2393 .show_fdinfo = tun_chr_show_fdinfo,
2394#endif
2395};
2396
2397static struct miscdevice tun_miscdev = {
2398 .minor = TUN_MINOR,
2399 .name = "tun",
2400 .nodename = "net/tun",
2401 .fops = &tun_fops,
2402};
2403
2404/* ethtool interface */
2405
2406static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2407{
2408 cmd->supported = 0;
2409 cmd->advertising = 0;
2410 ethtool_cmd_speed_set(cmd, SPEED_10);
2411 cmd->duplex = DUPLEX_FULL;
2412 cmd->port = PORT_TP;
2413 cmd->phy_address = 0;
2414 cmd->transceiver = XCVR_INTERNAL;
2415 cmd->autoneg = AUTONEG_DISABLE;
2416 cmd->maxtxpkt = 0;
2417 cmd->maxrxpkt = 0;
2418 return 0;
2419}
2420
2421static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2422{
2423 struct tun_struct *tun = netdev_priv(dev);
2424
2425 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2426 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2427
2428 switch (tun->flags & TUN_TYPE_MASK) {
2429 case IFF_TUN:
2430 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2431 break;
2432 case IFF_TAP:
2433 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2434 break;
2435 }
2436}
2437
2438static u32 tun_get_msglevel(struct net_device *dev)
2439{
2440#ifdef TUN_DEBUG
2441 struct tun_struct *tun = netdev_priv(dev);
2442 return tun->debug;
2443#else
2444 return -EOPNOTSUPP;
2445#endif
2446}
2447
2448static void tun_set_msglevel(struct net_device *dev, u32 value)
2449{
2450#ifdef TUN_DEBUG
2451 struct tun_struct *tun = netdev_priv(dev);
2452 tun->debug = value;
2453#endif
2454}
2455
2456static const struct ethtool_ops tun_ethtool_ops = {
2457 .get_settings = tun_get_settings,
2458 .get_drvinfo = tun_get_drvinfo,
2459 .get_msglevel = tun_get_msglevel,
2460 .set_msglevel = tun_set_msglevel,
2461 .get_link = ethtool_op_get_link,
2462 .get_ts_info = ethtool_op_get_ts_info,
2463};
2464
2465static int tun_queue_resize(struct tun_struct *tun)
2466{
2467 struct net_device *dev = tun->dev;
2468 struct tun_file *tfile;
2469 struct skb_array **arrays;
2470 int n = tun->numqueues + tun->numdisabled;
2471 int ret, i;
2472
2473 arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL);
2474 if (!arrays)
2475 return -ENOMEM;
2476
2477 for (i = 0; i < tun->numqueues; i++) {
2478 tfile = rtnl_dereference(tun->tfiles[i]);
2479 arrays[i] = &tfile->tx_array;
2480 }
2481 list_for_each_entry(tfile, &tun->disabled, next)
2482 arrays[i++] = &tfile->tx_array;
2483
2484 ret = skb_array_resize_multiple(arrays, n,
2485 dev->tx_queue_len, GFP_KERNEL);
2486
2487 kfree(arrays);
2488 return ret;
2489}
2490
2491static int tun_device_event(struct notifier_block *unused,
2492 unsigned long event, void *ptr)
2493{
2494 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
2495 struct tun_struct *tun = netdev_priv(dev);
2496
2497 if (dev->rtnl_link_ops != &tun_link_ops)
2498 return NOTIFY_DONE;
2499
2500 switch (event) {
2501 case NETDEV_CHANGE_TX_QUEUE_LEN:
2502 if (tun_queue_resize(tun))
2503 return NOTIFY_BAD;
2504 break;
2505 default:
2506 break;
2507 }
2508
2509 return NOTIFY_DONE;
2510}
2511
2512static struct notifier_block tun_notifier_block __read_mostly = {
2513 .notifier_call = tun_device_event,
2514};
2515
2516static int __init tun_init(void)
2517{
2518 int ret = 0;
2519
2520 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2521 pr_info("%s\n", DRV_COPYRIGHT);
2522
2523 ret = rtnl_link_register(&tun_link_ops);
2524 if (ret) {
2525 pr_err("Can't register link_ops\n");
2526 goto err_linkops;
2527 }
2528
2529 ret = misc_register(&tun_miscdev);
2530 if (ret) {
2531 pr_err("Can't register misc device %d\n", TUN_MINOR);
2532 goto err_misc;
2533 }
2534
2535 register_netdevice_notifier(&tun_notifier_block);
2536 return 0;
2537err_misc:
2538 rtnl_link_unregister(&tun_link_ops);
2539err_linkops:
2540 return ret;
2541}
2542
2543static void tun_cleanup(void)
2544{
2545 misc_deregister(&tun_miscdev);
2546 rtnl_link_unregister(&tun_link_ops);
2547 unregister_netdevice_notifier(&tun_notifier_block);
2548}
2549
2550/* Get an underlying socket object from tun file. Returns error unless file is
2551 * attached to a device. The returned object works like a packet socket, it
2552 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
2553 * holding a reference to the file for as long as the socket is in use. */
2554struct socket *tun_get_socket(struct file *file)
2555{
2556 struct tun_file *tfile;
2557 if (file->f_op != &tun_fops)
2558 return ERR_PTR(-EINVAL);
2559 tfile = file->private_data;
2560 if (!tfile)
2561 return ERR_PTR(-EBADFD);
2562 return &tfile->socket;
2563}
2564EXPORT_SYMBOL_GPL(tun_get_socket);
2565
2566module_init(tun_init);
2567module_exit(tun_cleanup);
2568MODULE_DESCRIPTION(DRV_DESCRIPTION);
2569MODULE_AUTHOR(DRV_COPYRIGHT);
2570MODULE_LICENSE("GPL");
2571MODULE_ALIAS_MISCDEV(TUN_MINOR);
2572MODULE_ALIAS("devname:net/tun");