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Merge branch 'master' of git://1984.lsi.us.es/nf-next
[deliverable/linux.git] / drivers / net / tun.c
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/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/uaccess.h>
73
74 /* Uncomment to enable debugging */
75 /* #define TUN_DEBUG 1 */
76
77 #ifdef TUN_DEBUG
78 static int debug;
79
80 #define tun_debug(level, tun, fmt, args...) \
81 do { \
82 if (tun->debug) \
83 netdev_printk(level, tun->dev, fmt, ##args); \
84 } while (0)
85 #define DBG1(level, fmt, args...) \
86 do { \
87 if (debug == 2) \
88 printk(level fmt, ##args); \
89 } while (0)
90 #else
91 #define tun_debug(level, tun, fmt, args...) \
92 do { \
93 if (0) \
94 netdev_printk(level, tun->dev, fmt, ##args); \
95 } while (0)
96 #define DBG1(level, fmt, args...) \
97 do { \
98 if (0) \
99 printk(level fmt, ##args); \
100 } while (0)
101 #endif
102
103 #define GOODCOPY_LEN 128
104
105 #define FLT_EXACT_COUNT 8
106 struct tap_filter {
107 unsigned int count; /* Number of addrs. Zero means disabled */
108 u32 mask[2]; /* Mask of the hashed addrs */
109 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
110 };
111
112 struct tun_file {
113 atomic_t count;
114 struct tun_struct *tun;
115 struct net *net;
116 };
117
118 struct tun_sock;
119
120 struct tun_struct {
121 struct tun_file *tfile;
122 unsigned int flags;
123 kuid_t owner;
124 kgid_t group;
125
126 struct net_device *dev;
127 netdev_features_t set_features;
128 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
129 NETIF_F_TSO6|NETIF_F_UFO)
130 struct fasync_struct *fasync;
131
132 struct tap_filter txflt;
133 struct socket socket;
134 struct socket_wq wq;
135
136 int vnet_hdr_sz;
137
138 #ifdef TUN_DEBUG
139 int debug;
140 #endif
141 };
142
143 struct tun_sock {
144 struct sock sk;
145 struct tun_struct *tun;
146 };
147
148 static inline struct tun_sock *tun_sk(struct sock *sk)
149 {
150 return container_of(sk, struct tun_sock, sk);
151 }
152
153 static int tun_attach(struct tun_struct *tun, struct file *file)
154 {
155 struct tun_file *tfile = file->private_data;
156 int err;
157
158 ASSERT_RTNL();
159
160 netif_tx_lock_bh(tun->dev);
161
162 err = -EINVAL;
163 if (tfile->tun)
164 goto out;
165
166 err = -EBUSY;
167 if (tun->tfile)
168 goto out;
169
170 err = 0;
171 tfile->tun = tun;
172 tun->tfile = tfile;
173 tun->socket.file = file;
174 netif_carrier_on(tun->dev);
175 dev_hold(tun->dev);
176 sock_hold(tun->socket.sk);
177 atomic_inc(&tfile->count);
178
179 out:
180 netif_tx_unlock_bh(tun->dev);
181 return err;
182 }
183
184 static void __tun_detach(struct tun_struct *tun)
185 {
186 /* Detach from net device */
187 netif_tx_lock_bh(tun->dev);
188 netif_carrier_off(tun->dev);
189 tun->tfile = 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
199 static void tun_detach(struct tun_struct *tun)
200 {
201 rtnl_lock();
202 __tun_detach(tun);
203 rtnl_unlock();
204 }
205
206 static 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
216 static struct tun_struct *tun_get(struct file *file)
217 {
218 return __tun_get(file->private_data);
219 }
220
221 static 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 */
230 static 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
236 static 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
242 static 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
302 done:
303 kfree(addr);
304 return err;
305 }
306
307 /* Returns: 0 - drop, !=0 - accept */
308 static 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 (ether_addr_equal(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 */
331 static 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
341 static const struct ethtool_ops tun_ethtool_ops;
342
343 /* Net device detach from fd. */
344 static 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
358 static void tun_free_netdev(struct net_device *dev)
359 {
360 struct tun_struct *tun = netdev_priv(dev);
361
362 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags));
363
364 sk_release_kernel(tun->socket.sk);
365 }
366
367 /* Net device open. */
368 static int tun_net_open(struct net_device *dev)
369 {
370 netif_start_queue(dev);
371 return 0;
372 }
373
374 /* Net device close. */
375 static int tun_net_close(struct net_device *dev)
376 {
377 netif_stop_queue(dev);
378 return 0;
379 }
380
381 /* Net device start xmit */
382 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
383 {
384 struct tun_struct *tun = netdev_priv(dev);
385
386 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
387
388 /* Drop packet if interface is not attached */
389 if (!tun->tfile)
390 goto drop;
391
392 /* Drop if the filter does not like it.
393 * This is a noop if the filter is disabled.
394 * Filter can be enabled only for the TAP devices. */
395 if (!check_filter(&tun->txflt, skb))
396 goto drop;
397
398 if (tun->socket.sk->sk_filter &&
399 sk_filter(tun->socket.sk, skb))
400 goto drop;
401
402 if (skb_queue_len(&tun->socket.sk->sk_receive_queue) >= dev->tx_queue_len) {
403 if (!(tun->flags & TUN_ONE_QUEUE)) {
404 /* Normal queueing mode. */
405 /* Packet scheduler handles dropping of further packets. */
406 netif_stop_queue(dev);
407
408 /* We won't see all dropped packets individually, so overrun
409 * error is more appropriate. */
410 dev->stats.tx_fifo_errors++;
411 } else {
412 /* Single queue mode.
413 * Driver handles dropping of all packets itself. */
414 goto drop;
415 }
416 }
417
418 /* Orphan the skb - required as we might hang on to it
419 * for indefinite time. */
420 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
421 goto drop;
422 skb_orphan(skb);
423
424 /* Enqueue packet */
425 skb_queue_tail(&tun->socket.sk->sk_receive_queue, skb);
426
427 /* Notify and wake up reader process */
428 if (tun->flags & TUN_FASYNC)
429 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
430 wake_up_interruptible_poll(&tun->wq.wait, POLLIN |
431 POLLRDNORM | POLLRDBAND);
432 return NETDEV_TX_OK;
433
434 drop:
435 dev->stats.tx_dropped++;
436 kfree_skb(skb);
437 return NETDEV_TX_OK;
438 }
439
440 static void tun_net_mclist(struct net_device *dev)
441 {
442 /*
443 * This callback is supposed to deal with mc filter in
444 * _rx_ path and has nothing to do with the _tx_ path.
445 * In rx path we always accept everything userspace gives us.
446 */
447 }
448
449 #define MIN_MTU 68
450 #define MAX_MTU 65535
451
452 static int
453 tun_net_change_mtu(struct net_device *dev, int new_mtu)
454 {
455 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
456 return -EINVAL;
457 dev->mtu = new_mtu;
458 return 0;
459 }
460
461 static netdev_features_t tun_net_fix_features(struct net_device *dev,
462 netdev_features_t features)
463 {
464 struct tun_struct *tun = netdev_priv(dev);
465
466 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
467 }
468 #ifdef CONFIG_NET_POLL_CONTROLLER
469 static void tun_poll_controller(struct net_device *dev)
470 {
471 /*
472 * Tun only receives frames when:
473 * 1) the char device endpoint gets data from user space
474 * 2) the tun socket gets a sendmsg call from user space
475 * Since both of those are syncronous operations, we are guaranteed
476 * never to have pending data when we poll for it
477 * so theres nothing to do here but return.
478 * We need this though so netpoll recognizes us as an interface that
479 * supports polling, which enables bridge devices in virt setups to
480 * still use netconsole
481 */
482 return;
483 }
484 #endif
485 static const struct net_device_ops tun_netdev_ops = {
486 .ndo_uninit = tun_net_uninit,
487 .ndo_open = tun_net_open,
488 .ndo_stop = tun_net_close,
489 .ndo_start_xmit = tun_net_xmit,
490 .ndo_change_mtu = tun_net_change_mtu,
491 .ndo_fix_features = tun_net_fix_features,
492 #ifdef CONFIG_NET_POLL_CONTROLLER
493 .ndo_poll_controller = tun_poll_controller,
494 #endif
495 };
496
497 static const struct net_device_ops tap_netdev_ops = {
498 .ndo_uninit = tun_net_uninit,
499 .ndo_open = tun_net_open,
500 .ndo_stop = tun_net_close,
501 .ndo_start_xmit = tun_net_xmit,
502 .ndo_change_mtu = tun_net_change_mtu,
503 .ndo_fix_features = tun_net_fix_features,
504 .ndo_set_rx_mode = tun_net_mclist,
505 .ndo_set_mac_address = eth_mac_addr,
506 .ndo_validate_addr = eth_validate_addr,
507 #ifdef CONFIG_NET_POLL_CONTROLLER
508 .ndo_poll_controller = tun_poll_controller,
509 #endif
510 };
511
512 /* Initialize net device. */
513 static void tun_net_init(struct net_device *dev)
514 {
515 struct tun_struct *tun = netdev_priv(dev);
516
517 switch (tun->flags & TUN_TYPE_MASK) {
518 case TUN_TUN_DEV:
519 dev->netdev_ops = &tun_netdev_ops;
520
521 /* Point-to-Point TUN Device */
522 dev->hard_header_len = 0;
523 dev->addr_len = 0;
524 dev->mtu = 1500;
525
526 /* Zero header length */
527 dev->type = ARPHRD_NONE;
528 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
529 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
530 break;
531
532 case TUN_TAP_DEV:
533 dev->netdev_ops = &tap_netdev_ops;
534 /* Ethernet TAP Device */
535 ether_setup(dev);
536 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
537
538 eth_hw_addr_random(dev);
539
540 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
541 break;
542 }
543 }
544
545 /* Character device part */
546
547 /* Poll */
548 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
549 {
550 struct tun_file *tfile = file->private_data;
551 struct tun_struct *tun = __tun_get(tfile);
552 struct sock *sk;
553 unsigned int mask = 0;
554
555 if (!tun)
556 return POLLERR;
557
558 sk = tun->socket.sk;
559
560 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
561
562 poll_wait(file, &tun->wq.wait, wait);
563
564 if (!skb_queue_empty(&sk->sk_receive_queue))
565 mask |= POLLIN | POLLRDNORM;
566
567 if (sock_writeable(sk) ||
568 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
569 sock_writeable(sk)))
570 mask |= POLLOUT | POLLWRNORM;
571
572 if (tun->dev->reg_state != NETREG_REGISTERED)
573 mask = POLLERR;
574
575 tun_put(tun);
576 return mask;
577 }
578
579 /* prepad is the amount to reserve at front. len is length after that.
580 * linear is a hint as to how much to copy (usually headers). */
581 static struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
582 size_t prepad, size_t len,
583 size_t linear, int noblock)
584 {
585 struct sock *sk = tun->socket.sk;
586 struct sk_buff *skb;
587 int err;
588
589 /* Under a page? Don't bother with paged skb. */
590 if (prepad + len < PAGE_SIZE || !linear)
591 linear = len;
592
593 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
594 &err);
595 if (!skb)
596 return ERR_PTR(err);
597
598 skb_reserve(skb, prepad);
599 skb_put(skb, linear);
600 skb->data_len = len - linear;
601 skb->len += len - linear;
602
603 return skb;
604 }
605
606 /* set skb frags from iovec, this can move to core network code for reuse */
607 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
608 int offset, size_t count)
609 {
610 int len = iov_length(from, count) - offset;
611 int copy = skb_headlen(skb);
612 int size, offset1 = 0;
613 int i = 0;
614
615 /* Skip over from offset */
616 while (count && (offset >= from->iov_len)) {
617 offset -= from->iov_len;
618 ++from;
619 --count;
620 }
621
622 /* copy up to skb headlen */
623 while (count && (copy > 0)) {
624 size = min_t(unsigned int, copy, from->iov_len - offset);
625 if (copy_from_user(skb->data + offset1, from->iov_base + offset,
626 size))
627 return -EFAULT;
628 if (copy > size) {
629 ++from;
630 --count;
631 offset = 0;
632 } else
633 offset += size;
634 copy -= size;
635 offset1 += size;
636 }
637
638 if (len == offset1)
639 return 0;
640
641 while (count--) {
642 struct page *page[MAX_SKB_FRAGS];
643 int num_pages;
644 unsigned long base;
645 unsigned long truesize;
646
647 len = from->iov_len - offset;
648 if (!len) {
649 offset = 0;
650 ++from;
651 continue;
652 }
653 base = (unsigned long)from->iov_base + offset;
654 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
655 if (i + size > MAX_SKB_FRAGS)
656 return -EMSGSIZE;
657 num_pages = get_user_pages_fast(base, size, 0, &page[i]);
658 if (num_pages != size) {
659 for (i = 0; i < num_pages; i++)
660 put_page(page[i]);
661 return -EFAULT;
662 }
663 truesize = size * PAGE_SIZE;
664 skb->data_len += len;
665 skb->len += len;
666 skb->truesize += truesize;
667 atomic_add(truesize, &skb->sk->sk_wmem_alloc);
668 while (len) {
669 int off = base & ~PAGE_MASK;
670 int size = min_t(int, len, PAGE_SIZE - off);
671 __skb_fill_page_desc(skb, i, page[i], off, size);
672 skb_shinfo(skb)->nr_frags++;
673 /* increase sk_wmem_alloc */
674 base += size;
675 len -= size;
676 i++;
677 }
678 offset = 0;
679 ++from;
680 }
681 return 0;
682 }
683
684 /* Get packet from user space buffer */
685 static ssize_t tun_get_user(struct tun_struct *tun, void *msg_control,
686 const struct iovec *iv, size_t total_len,
687 size_t count, int noblock)
688 {
689 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
690 struct sk_buff *skb;
691 size_t len = total_len, align = NET_SKB_PAD;
692 struct virtio_net_hdr gso = { 0 };
693 int offset = 0;
694 int copylen;
695 bool zerocopy = false;
696 int err;
697
698 if (!(tun->flags & TUN_NO_PI)) {
699 if ((len -= sizeof(pi)) > total_len)
700 return -EINVAL;
701
702 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
703 return -EFAULT;
704 offset += sizeof(pi);
705 }
706
707 if (tun->flags & TUN_VNET_HDR) {
708 if ((len -= tun->vnet_hdr_sz) > total_len)
709 return -EINVAL;
710
711 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
712 return -EFAULT;
713
714 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
715 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
716 gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
717
718 if (gso.hdr_len > len)
719 return -EINVAL;
720 offset += tun->vnet_hdr_sz;
721 }
722
723 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
724 align += NET_IP_ALIGN;
725 if (unlikely(len < ETH_HLEN ||
726 (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
727 return -EINVAL;
728 }
729
730 if (msg_control)
731 zerocopy = true;
732
733 if (zerocopy) {
734 /* Userspace may produce vectors with count greater than
735 * MAX_SKB_FRAGS, so we need to linearize parts of the skb
736 * to let the rest of data to be fit in the frags.
737 */
738 if (count > MAX_SKB_FRAGS) {
739 copylen = iov_length(iv, count - MAX_SKB_FRAGS);
740 if (copylen < offset)
741 copylen = 0;
742 else
743 copylen -= offset;
744 } else
745 copylen = 0;
746 /* There are 256 bytes to be copied in skb, so there is enough
747 * room for skb expand head in case it is used.
748 * The rest of the buffer is mapped from userspace.
749 */
750 if (copylen < gso.hdr_len)
751 copylen = gso.hdr_len;
752 if (!copylen)
753 copylen = GOODCOPY_LEN;
754 } else
755 copylen = len;
756
757 skb = tun_alloc_skb(tun, align, copylen, gso.hdr_len, noblock);
758 if (IS_ERR(skb)) {
759 if (PTR_ERR(skb) != -EAGAIN)
760 tun->dev->stats.rx_dropped++;
761 return PTR_ERR(skb);
762 }
763
764 if (zerocopy)
765 err = zerocopy_sg_from_iovec(skb, iv, offset, count);
766 else
767 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
768
769 if (err) {
770 tun->dev->stats.rx_dropped++;
771 kfree_skb(skb);
772 return -EFAULT;
773 }
774
775 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
776 if (!skb_partial_csum_set(skb, gso.csum_start,
777 gso.csum_offset)) {
778 tun->dev->stats.rx_frame_errors++;
779 kfree_skb(skb);
780 return -EINVAL;
781 }
782 }
783
784 switch (tun->flags & TUN_TYPE_MASK) {
785 case TUN_TUN_DEV:
786 if (tun->flags & TUN_NO_PI) {
787 switch (skb->data[0] & 0xf0) {
788 case 0x40:
789 pi.proto = htons(ETH_P_IP);
790 break;
791 case 0x60:
792 pi.proto = htons(ETH_P_IPV6);
793 break;
794 default:
795 tun->dev->stats.rx_dropped++;
796 kfree_skb(skb);
797 return -EINVAL;
798 }
799 }
800
801 skb_reset_mac_header(skb);
802 skb->protocol = pi.proto;
803 skb->dev = tun->dev;
804 break;
805 case TUN_TAP_DEV:
806 skb->protocol = eth_type_trans(skb, tun->dev);
807 break;
808 }
809
810 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
811 pr_debug("GSO!\n");
812 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
813 case VIRTIO_NET_HDR_GSO_TCPV4:
814 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
815 break;
816 case VIRTIO_NET_HDR_GSO_TCPV6:
817 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
818 break;
819 case VIRTIO_NET_HDR_GSO_UDP:
820 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
821 break;
822 default:
823 tun->dev->stats.rx_frame_errors++;
824 kfree_skb(skb);
825 return -EINVAL;
826 }
827
828 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
829 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
830
831 skb_shinfo(skb)->gso_size = gso.gso_size;
832 if (skb_shinfo(skb)->gso_size == 0) {
833 tun->dev->stats.rx_frame_errors++;
834 kfree_skb(skb);
835 return -EINVAL;
836 }
837
838 /* Header must be checked, and gso_segs computed. */
839 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
840 skb_shinfo(skb)->gso_segs = 0;
841 }
842
843 /* copy skb_ubuf_info for callback when skb has no error */
844 if (zerocopy) {
845 skb_shinfo(skb)->destructor_arg = msg_control;
846 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
847 }
848
849 netif_rx_ni(skb);
850
851 tun->dev->stats.rx_packets++;
852 tun->dev->stats.rx_bytes += len;
853
854 return total_len;
855 }
856
857 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
858 unsigned long count, loff_t pos)
859 {
860 struct file *file = iocb->ki_filp;
861 struct tun_struct *tun = tun_get(file);
862 ssize_t result;
863
864 if (!tun)
865 return -EBADFD;
866
867 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
868
869 result = tun_get_user(tun, NULL, iv, iov_length(iv, count), count,
870 file->f_flags & O_NONBLOCK);
871
872 tun_put(tun);
873 return result;
874 }
875
876 /* Put packet to the user space buffer */
877 static ssize_t tun_put_user(struct tun_struct *tun,
878 struct sk_buff *skb,
879 const struct iovec *iv, int len)
880 {
881 struct tun_pi pi = { 0, skb->protocol };
882 ssize_t total = 0;
883
884 if (!(tun->flags & TUN_NO_PI)) {
885 if ((len -= sizeof(pi)) < 0)
886 return -EINVAL;
887
888 if (len < skb->len) {
889 /* Packet will be striped */
890 pi.flags |= TUN_PKT_STRIP;
891 }
892
893 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
894 return -EFAULT;
895 total += sizeof(pi);
896 }
897
898 if (tun->flags & TUN_VNET_HDR) {
899 struct virtio_net_hdr gso = { 0 }; /* no info leak */
900 if ((len -= tun->vnet_hdr_sz) < 0)
901 return -EINVAL;
902
903 if (skb_is_gso(skb)) {
904 struct skb_shared_info *sinfo = skb_shinfo(skb);
905
906 /* This is a hint as to how much should be linear. */
907 gso.hdr_len = skb_headlen(skb);
908 gso.gso_size = sinfo->gso_size;
909 if (sinfo->gso_type & SKB_GSO_TCPV4)
910 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
911 else if (sinfo->gso_type & SKB_GSO_TCPV6)
912 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
913 else if (sinfo->gso_type & SKB_GSO_UDP)
914 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
915 else {
916 pr_err("unexpected GSO type: "
917 "0x%x, gso_size %d, hdr_len %d\n",
918 sinfo->gso_type, gso.gso_size,
919 gso.hdr_len);
920 print_hex_dump(KERN_ERR, "tun: ",
921 DUMP_PREFIX_NONE,
922 16, 1, skb->head,
923 min((int)gso.hdr_len, 64), true);
924 WARN_ON_ONCE(1);
925 return -EINVAL;
926 }
927 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
928 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
929 } else
930 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
931
932 if (skb->ip_summed == CHECKSUM_PARTIAL) {
933 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
934 gso.csum_start = skb_checksum_start_offset(skb);
935 gso.csum_offset = skb->csum_offset;
936 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
937 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
938 } /* else everything is zero */
939
940 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
941 sizeof(gso))))
942 return -EFAULT;
943 total += tun->vnet_hdr_sz;
944 }
945
946 len = min_t(int, skb->len, len);
947
948 skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
949 total += skb->len;
950
951 tun->dev->stats.tx_packets++;
952 tun->dev->stats.tx_bytes += len;
953
954 return total;
955 }
956
957 static ssize_t tun_do_read(struct tun_struct *tun,
958 struct kiocb *iocb, const struct iovec *iv,
959 ssize_t len, int noblock)
960 {
961 DECLARE_WAITQUEUE(wait, current);
962 struct sk_buff *skb;
963 ssize_t ret = 0;
964
965 tun_debug(KERN_INFO, tun, "tun_chr_read\n");
966
967 if (unlikely(!noblock))
968 add_wait_queue(&tun->wq.wait, &wait);
969 while (len) {
970 current->state = TASK_INTERRUPTIBLE;
971
972 /* Read frames from the queue */
973 if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) {
974 if (noblock) {
975 ret = -EAGAIN;
976 break;
977 }
978 if (signal_pending(current)) {
979 ret = -ERESTARTSYS;
980 break;
981 }
982 if (tun->dev->reg_state != NETREG_REGISTERED) {
983 ret = -EIO;
984 break;
985 }
986
987 /* Nothing to read, let's sleep */
988 schedule();
989 continue;
990 }
991 netif_wake_queue(tun->dev);
992
993 ret = tun_put_user(tun, skb, iv, len);
994 kfree_skb(skb);
995 break;
996 }
997
998 current->state = TASK_RUNNING;
999 if (unlikely(!noblock))
1000 remove_wait_queue(&tun->wq.wait, &wait);
1001
1002 return ret;
1003 }
1004
1005 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1006 unsigned long count, loff_t pos)
1007 {
1008 struct file *file = iocb->ki_filp;
1009 struct tun_file *tfile = file->private_data;
1010 struct tun_struct *tun = __tun_get(tfile);
1011 ssize_t len, ret;
1012
1013 if (!tun)
1014 return -EBADFD;
1015 len = iov_length(iv, count);
1016 if (len < 0) {
1017 ret = -EINVAL;
1018 goto out;
1019 }
1020
1021 ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK);
1022 ret = min_t(ssize_t, ret, len);
1023 out:
1024 tun_put(tun);
1025 return ret;
1026 }
1027
1028 static void tun_setup(struct net_device *dev)
1029 {
1030 struct tun_struct *tun = netdev_priv(dev);
1031
1032 tun->owner = INVALID_UID;
1033 tun->group = INVALID_GID;
1034
1035 dev->ethtool_ops = &tun_ethtool_ops;
1036 dev->destructor = tun_free_netdev;
1037 }
1038
1039 /* Trivial set of netlink ops to allow deleting tun or tap
1040 * device with netlink.
1041 */
1042 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1043 {
1044 return -EINVAL;
1045 }
1046
1047 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1048 .kind = DRV_NAME,
1049 .priv_size = sizeof(struct tun_struct),
1050 .setup = tun_setup,
1051 .validate = tun_validate,
1052 };
1053
1054 static void tun_sock_write_space(struct sock *sk)
1055 {
1056 struct tun_struct *tun;
1057 wait_queue_head_t *wqueue;
1058
1059 if (!sock_writeable(sk))
1060 return;
1061
1062 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1063 return;
1064
1065 wqueue = sk_sleep(sk);
1066 if (wqueue && waitqueue_active(wqueue))
1067 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1068 POLLWRNORM | POLLWRBAND);
1069
1070 tun = tun_sk(sk)->tun;
1071 kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
1072 }
1073
1074 static void tun_sock_destruct(struct sock *sk)
1075 {
1076 free_netdev(tun_sk(sk)->tun->dev);
1077 }
1078
1079 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1080 struct msghdr *m, size_t total_len)
1081 {
1082 struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
1083 return tun_get_user(tun, m->msg_control, m->msg_iov, total_len,
1084 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1085 }
1086
1087 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1088 struct msghdr *m, size_t total_len,
1089 int flags)
1090 {
1091 struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
1092 int ret;
1093 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1094 return -EINVAL;
1095 ret = tun_do_read(tun, iocb, m->msg_iov, total_len,
1096 flags & MSG_DONTWAIT);
1097 if (ret > total_len) {
1098 m->msg_flags |= MSG_TRUNC;
1099 ret = flags & MSG_TRUNC ? ret : total_len;
1100 }
1101 return ret;
1102 }
1103
1104 static int tun_release(struct socket *sock)
1105 {
1106 if (sock->sk)
1107 sock_put(sock->sk);
1108 return 0;
1109 }
1110
1111 /* Ops structure to mimic raw sockets with tun */
1112 static const struct proto_ops tun_socket_ops = {
1113 .sendmsg = tun_sendmsg,
1114 .recvmsg = tun_recvmsg,
1115 .release = tun_release,
1116 };
1117
1118 static struct proto tun_proto = {
1119 .name = "tun",
1120 .owner = THIS_MODULE,
1121 .obj_size = sizeof(struct tun_sock),
1122 };
1123
1124 static int tun_flags(struct tun_struct *tun)
1125 {
1126 int flags = 0;
1127
1128 if (tun->flags & TUN_TUN_DEV)
1129 flags |= IFF_TUN;
1130 else
1131 flags |= IFF_TAP;
1132
1133 if (tun->flags & TUN_NO_PI)
1134 flags |= IFF_NO_PI;
1135
1136 if (tun->flags & TUN_ONE_QUEUE)
1137 flags |= IFF_ONE_QUEUE;
1138
1139 if (tun->flags & TUN_VNET_HDR)
1140 flags |= IFF_VNET_HDR;
1141
1142 return flags;
1143 }
1144
1145 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1146 char *buf)
1147 {
1148 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1149 return sprintf(buf, "0x%x\n", tun_flags(tun));
1150 }
1151
1152 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1153 char *buf)
1154 {
1155 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1156 return uid_valid(tun->owner)?
1157 sprintf(buf, "%u\n",
1158 from_kuid_munged(current_user_ns(), tun->owner)):
1159 sprintf(buf, "-1\n");
1160 }
1161
1162 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1163 char *buf)
1164 {
1165 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1166 return gid_valid(tun->group) ?
1167 sprintf(buf, "%u\n",
1168 from_kgid_munged(current_user_ns(), tun->group)):
1169 sprintf(buf, "-1\n");
1170 }
1171
1172 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1173 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1174 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1175
1176 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1177 {
1178 struct sock *sk;
1179 struct tun_struct *tun;
1180 struct net_device *dev;
1181 int err;
1182
1183 dev = __dev_get_by_name(net, ifr->ifr_name);
1184 if (dev) {
1185 const struct cred *cred = current_cred();
1186
1187 if (ifr->ifr_flags & IFF_TUN_EXCL)
1188 return -EBUSY;
1189 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1190 tun = netdev_priv(dev);
1191 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1192 tun = netdev_priv(dev);
1193 else
1194 return -EINVAL;
1195
1196 if (((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
1197 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
1198 !capable(CAP_NET_ADMIN))
1199 return -EPERM;
1200 err = security_tun_dev_attach(tun->socket.sk);
1201 if (err < 0)
1202 return err;
1203
1204 err = tun_attach(tun, file);
1205 if (err < 0)
1206 return err;
1207 }
1208 else {
1209 char *name;
1210 unsigned long flags = 0;
1211
1212 if (!capable(CAP_NET_ADMIN))
1213 return -EPERM;
1214 err = security_tun_dev_create();
1215 if (err < 0)
1216 return err;
1217
1218 /* Set dev type */
1219 if (ifr->ifr_flags & IFF_TUN) {
1220 /* TUN device */
1221 flags |= TUN_TUN_DEV;
1222 name = "tun%d";
1223 } else if (ifr->ifr_flags & IFF_TAP) {
1224 /* TAP device */
1225 flags |= TUN_TAP_DEV;
1226 name = "tap%d";
1227 } else
1228 return -EINVAL;
1229
1230 if (*ifr->ifr_name)
1231 name = ifr->ifr_name;
1232
1233 dev = alloc_netdev(sizeof(struct tun_struct), name,
1234 tun_setup);
1235 if (!dev)
1236 return -ENOMEM;
1237
1238 dev_net_set(dev, net);
1239 dev->rtnl_link_ops = &tun_link_ops;
1240
1241 tun = netdev_priv(dev);
1242 tun->dev = dev;
1243 tun->flags = flags;
1244 tun->txflt.count = 0;
1245 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1246 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags);
1247
1248 err = -ENOMEM;
1249 sk = sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
1250 if (!sk)
1251 goto err_free_dev;
1252
1253 sk_change_net(sk, net);
1254 tun->socket.wq = &tun->wq;
1255 init_waitqueue_head(&tun->wq.wait);
1256 tun->socket.ops = &tun_socket_ops;
1257 sock_init_data(&tun->socket, sk);
1258 sk->sk_write_space = tun_sock_write_space;
1259 sk->sk_sndbuf = INT_MAX;
1260 sock_set_flag(sk, SOCK_ZEROCOPY);
1261
1262 tun_sk(sk)->tun = tun;
1263
1264 security_tun_dev_post_create(sk);
1265
1266 tun_net_init(dev);
1267
1268 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1269 TUN_USER_FEATURES;
1270 dev->features = dev->hw_features;
1271
1272 err = register_netdevice(tun->dev);
1273 if (err < 0)
1274 goto err_free_sk;
1275
1276 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1277 device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1278 device_create_file(&tun->dev->dev, &dev_attr_group))
1279 pr_err("Failed to create tun sysfs files\n");
1280
1281 sk->sk_destruct = tun_sock_destruct;
1282
1283 err = tun_attach(tun, file);
1284 if (err < 0)
1285 goto failed;
1286 }
1287
1288 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1289
1290 if (ifr->ifr_flags & IFF_NO_PI)
1291 tun->flags |= TUN_NO_PI;
1292 else
1293 tun->flags &= ~TUN_NO_PI;
1294
1295 if (ifr->ifr_flags & IFF_ONE_QUEUE)
1296 tun->flags |= TUN_ONE_QUEUE;
1297 else
1298 tun->flags &= ~TUN_ONE_QUEUE;
1299
1300 if (ifr->ifr_flags & IFF_VNET_HDR)
1301 tun->flags |= TUN_VNET_HDR;
1302 else
1303 tun->flags &= ~TUN_VNET_HDR;
1304
1305 /* Make sure persistent devices do not get stuck in
1306 * xoff state.
1307 */
1308 if (netif_running(tun->dev))
1309 netif_wake_queue(tun->dev);
1310
1311 strcpy(ifr->ifr_name, tun->dev->name);
1312 return 0;
1313
1314 err_free_sk:
1315 tun_free_netdev(dev);
1316 err_free_dev:
1317 free_netdev(dev);
1318 failed:
1319 return err;
1320 }
1321
1322 static int tun_get_iff(struct net *net, struct tun_struct *tun,
1323 struct ifreq *ifr)
1324 {
1325 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1326
1327 strcpy(ifr->ifr_name, tun->dev->name);
1328
1329 ifr->ifr_flags = tun_flags(tun);
1330
1331 return 0;
1332 }
1333
1334 /* This is like a cut-down ethtool ops, except done via tun fd so no
1335 * privs required. */
1336 static int set_offload(struct tun_struct *tun, unsigned long arg)
1337 {
1338 netdev_features_t features = 0;
1339
1340 if (arg & TUN_F_CSUM) {
1341 features |= NETIF_F_HW_CSUM;
1342 arg &= ~TUN_F_CSUM;
1343
1344 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1345 if (arg & TUN_F_TSO_ECN) {
1346 features |= NETIF_F_TSO_ECN;
1347 arg &= ~TUN_F_TSO_ECN;
1348 }
1349 if (arg & TUN_F_TSO4)
1350 features |= NETIF_F_TSO;
1351 if (arg & TUN_F_TSO6)
1352 features |= NETIF_F_TSO6;
1353 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1354 }
1355
1356 if (arg & TUN_F_UFO) {
1357 features |= NETIF_F_UFO;
1358 arg &= ~TUN_F_UFO;
1359 }
1360 }
1361
1362 /* This gives the user a way to test for new features in future by
1363 * trying to set them. */
1364 if (arg)
1365 return -EINVAL;
1366
1367 tun->set_features = features;
1368 netdev_update_features(tun->dev);
1369
1370 return 0;
1371 }
1372
1373 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1374 unsigned long arg, int ifreq_len)
1375 {
1376 struct tun_file *tfile = file->private_data;
1377 struct tun_struct *tun;
1378 void __user* argp = (void __user*)arg;
1379 struct sock_fprog fprog;
1380 struct ifreq ifr;
1381 kuid_t owner;
1382 kgid_t group;
1383 int sndbuf;
1384 int vnet_hdr_sz;
1385 int ret;
1386
1387 if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) {
1388 if (copy_from_user(&ifr, argp, ifreq_len))
1389 return -EFAULT;
1390 } else {
1391 memset(&ifr, 0, sizeof(ifr));
1392 }
1393 if (cmd == TUNGETFEATURES) {
1394 /* Currently this just means: "what IFF flags are valid?".
1395 * This is needed because we never checked for invalid flags on
1396 * TUNSETIFF. */
1397 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1398 IFF_VNET_HDR,
1399 (unsigned int __user*)argp);
1400 }
1401
1402 rtnl_lock();
1403
1404 tun = __tun_get(tfile);
1405 if (cmd == TUNSETIFF && !tun) {
1406 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1407
1408 ret = tun_set_iff(tfile->net, file, &ifr);
1409
1410 if (ret)
1411 goto unlock;
1412
1413 if (copy_to_user(argp, &ifr, ifreq_len))
1414 ret = -EFAULT;
1415 goto unlock;
1416 }
1417
1418 ret = -EBADFD;
1419 if (!tun)
1420 goto unlock;
1421
1422 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %d\n", cmd);
1423
1424 ret = 0;
1425 switch (cmd) {
1426 case TUNGETIFF:
1427 ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1428 if (ret)
1429 break;
1430
1431 if (copy_to_user(argp, &ifr, ifreq_len))
1432 ret = -EFAULT;
1433 break;
1434
1435 case TUNSETNOCSUM:
1436 /* Disable/Enable checksum */
1437
1438 /* [unimplemented] */
1439 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1440 arg ? "disabled" : "enabled");
1441 break;
1442
1443 case TUNSETPERSIST:
1444 /* Disable/Enable persist mode */
1445 if (arg)
1446 tun->flags |= TUN_PERSIST;
1447 else
1448 tun->flags &= ~TUN_PERSIST;
1449
1450 tun_debug(KERN_INFO, tun, "persist %s\n",
1451 arg ? "enabled" : "disabled");
1452 break;
1453
1454 case TUNSETOWNER:
1455 /* Set owner of the device */
1456 owner = make_kuid(current_user_ns(), arg);
1457 if (!uid_valid(owner)) {
1458 ret = -EINVAL;
1459 break;
1460 }
1461 tun->owner = owner;
1462 tun_debug(KERN_INFO, tun, "owner set to %d\n",
1463 from_kuid(&init_user_ns, tun->owner));
1464 break;
1465
1466 case TUNSETGROUP:
1467 /* Set group of the device */
1468 group = make_kgid(current_user_ns(), arg);
1469 if (!gid_valid(group)) {
1470 ret = -EINVAL;
1471 break;
1472 }
1473 tun->group = group;
1474 tun_debug(KERN_INFO, tun, "group set to %d\n",
1475 from_kgid(&init_user_ns, tun->group));
1476 break;
1477
1478 case TUNSETLINK:
1479 /* Only allow setting the type when the interface is down */
1480 if (tun->dev->flags & IFF_UP) {
1481 tun_debug(KERN_INFO, tun,
1482 "Linktype set failed because interface is up\n");
1483 ret = -EBUSY;
1484 } else {
1485 tun->dev->type = (int) arg;
1486 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1487 tun->dev->type);
1488 ret = 0;
1489 }
1490 break;
1491
1492 #ifdef TUN_DEBUG
1493 case TUNSETDEBUG:
1494 tun->debug = arg;
1495 break;
1496 #endif
1497 case TUNSETOFFLOAD:
1498 ret = set_offload(tun, arg);
1499 break;
1500
1501 case TUNSETTXFILTER:
1502 /* Can be set only for TAPs */
1503 ret = -EINVAL;
1504 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1505 break;
1506 ret = update_filter(&tun->txflt, (void __user *)arg);
1507 break;
1508
1509 case SIOCGIFHWADDR:
1510 /* Get hw address */
1511 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1512 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1513 if (copy_to_user(argp, &ifr, ifreq_len))
1514 ret = -EFAULT;
1515 break;
1516
1517 case SIOCSIFHWADDR:
1518 /* Set hw address */
1519 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1520 ifr.ifr_hwaddr.sa_data);
1521
1522 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1523 break;
1524
1525 case TUNGETSNDBUF:
1526 sndbuf = tun->socket.sk->sk_sndbuf;
1527 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1528 ret = -EFAULT;
1529 break;
1530
1531 case TUNSETSNDBUF:
1532 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1533 ret = -EFAULT;
1534 break;
1535 }
1536
1537 tun->socket.sk->sk_sndbuf = sndbuf;
1538 break;
1539
1540 case TUNGETVNETHDRSZ:
1541 vnet_hdr_sz = tun->vnet_hdr_sz;
1542 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
1543 ret = -EFAULT;
1544 break;
1545
1546 case TUNSETVNETHDRSZ:
1547 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
1548 ret = -EFAULT;
1549 break;
1550 }
1551 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
1552 ret = -EINVAL;
1553 break;
1554 }
1555
1556 tun->vnet_hdr_sz = vnet_hdr_sz;
1557 break;
1558
1559 case TUNATTACHFILTER:
1560 /* Can be set only for TAPs */
1561 ret = -EINVAL;
1562 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1563 break;
1564 ret = -EFAULT;
1565 if (copy_from_user(&fprog, argp, sizeof(fprog)))
1566 break;
1567
1568 ret = sk_attach_filter(&fprog, tun->socket.sk);
1569 break;
1570
1571 case TUNDETACHFILTER:
1572 /* Can be set only for TAPs */
1573 ret = -EINVAL;
1574 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1575 break;
1576 ret = sk_detach_filter(tun->socket.sk);
1577 break;
1578
1579 default:
1580 ret = -EINVAL;
1581 break;
1582 }
1583
1584 unlock:
1585 rtnl_unlock();
1586 if (tun)
1587 tun_put(tun);
1588 return ret;
1589 }
1590
1591 static long tun_chr_ioctl(struct file *file,
1592 unsigned int cmd, unsigned long arg)
1593 {
1594 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
1595 }
1596
1597 #ifdef CONFIG_COMPAT
1598 static long tun_chr_compat_ioctl(struct file *file,
1599 unsigned int cmd, unsigned long arg)
1600 {
1601 switch (cmd) {
1602 case TUNSETIFF:
1603 case TUNGETIFF:
1604 case TUNSETTXFILTER:
1605 case TUNGETSNDBUF:
1606 case TUNSETSNDBUF:
1607 case SIOCGIFHWADDR:
1608 case SIOCSIFHWADDR:
1609 arg = (unsigned long)compat_ptr(arg);
1610 break;
1611 default:
1612 arg = (compat_ulong_t)arg;
1613 break;
1614 }
1615
1616 /*
1617 * compat_ifreq is shorter than ifreq, so we must not access beyond
1618 * the end of that structure. All fields that are used in this
1619 * driver are compatible though, we don't need to convert the
1620 * contents.
1621 */
1622 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
1623 }
1624 #endif /* CONFIG_COMPAT */
1625
1626 static int tun_chr_fasync(int fd, struct file *file, int on)
1627 {
1628 struct tun_struct *tun = tun_get(file);
1629 int ret;
1630
1631 if (!tun)
1632 return -EBADFD;
1633
1634 tun_debug(KERN_INFO, tun, "tun_chr_fasync %d\n", on);
1635
1636 if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1637 goto out;
1638
1639 if (on) {
1640 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1641 if (ret)
1642 goto out;
1643 tun->flags |= TUN_FASYNC;
1644 } else
1645 tun->flags &= ~TUN_FASYNC;
1646 ret = 0;
1647 out:
1648 tun_put(tun);
1649 return ret;
1650 }
1651
1652 static int tun_chr_open(struct inode *inode, struct file * file)
1653 {
1654 struct tun_file *tfile;
1655
1656 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
1657
1658 tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1659 if (!tfile)
1660 return -ENOMEM;
1661 atomic_set(&tfile->count, 0);
1662 tfile->tun = NULL;
1663 tfile->net = get_net(current->nsproxy->net_ns);
1664 file->private_data = tfile;
1665 return 0;
1666 }
1667
1668 static int tun_chr_close(struct inode *inode, struct file *file)
1669 {
1670 struct tun_file *tfile = file->private_data;
1671 struct tun_struct *tun;
1672
1673 tun = __tun_get(tfile);
1674 if (tun) {
1675 struct net_device *dev = tun->dev;
1676
1677 tun_debug(KERN_INFO, tun, "tun_chr_close\n");
1678
1679 __tun_detach(tun);
1680
1681 /* If desirable, unregister the netdevice. */
1682 if (!(tun->flags & TUN_PERSIST)) {
1683 rtnl_lock();
1684 if (dev->reg_state == NETREG_REGISTERED)
1685 unregister_netdevice(dev);
1686 rtnl_unlock();
1687 }
1688 }
1689
1690 tun = tfile->tun;
1691 if (tun)
1692 sock_put(tun->socket.sk);
1693
1694 put_net(tfile->net);
1695 kfree(tfile);
1696
1697 return 0;
1698 }
1699
1700 static const struct file_operations tun_fops = {
1701 .owner = THIS_MODULE,
1702 .llseek = no_llseek,
1703 .read = do_sync_read,
1704 .aio_read = tun_chr_aio_read,
1705 .write = do_sync_write,
1706 .aio_write = tun_chr_aio_write,
1707 .poll = tun_chr_poll,
1708 .unlocked_ioctl = tun_chr_ioctl,
1709 #ifdef CONFIG_COMPAT
1710 .compat_ioctl = tun_chr_compat_ioctl,
1711 #endif
1712 .open = tun_chr_open,
1713 .release = tun_chr_close,
1714 .fasync = tun_chr_fasync
1715 };
1716
1717 static struct miscdevice tun_miscdev = {
1718 .minor = TUN_MINOR,
1719 .name = "tun",
1720 .nodename = "net/tun",
1721 .fops = &tun_fops,
1722 };
1723
1724 /* ethtool interface */
1725
1726 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1727 {
1728 cmd->supported = 0;
1729 cmd->advertising = 0;
1730 ethtool_cmd_speed_set(cmd, SPEED_10);
1731 cmd->duplex = DUPLEX_FULL;
1732 cmd->port = PORT_TP;
1733 cmd->phy_address = 0;
1734 cmd->transceiver = XCVR_INTERNAL;
1735 cmd->autoneg = AUTONEG_DISABLE;
1736 cmd->maxtxpkt = 0;
1737 cmd->maxrxpkt = 0;
1738 return 0;
1739 }
1740
1741 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1742 {
1743 struct tun_struct *tun = netdev_priv(dev);
1744
1745 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
1746 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
1747
1748 switch (tun->flags & TUN_TYPE_MASK) {
1749 case TUN_TUN_DEV:
1750 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
1751 break;
1752 case TUN_TAP_DEV:
1753 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
1754 break;
1755 }
1756 }
1757
1758 static u32 tun_get_msglevel(struct net_device *dev)
1759 {
1760 #ifdef TUN_DEBUG
1761 struct tun_struct *tun = netdev_priv(dev);
1762 return tun->debug;
1763 #else
1764 return -EOPNOTSUPP;
1765 #endif
1766 }
1767
1768 static void tun_set_msglevel(struct net_device *dev, u32 value)
1769 {
1770 #ifdef TUN_DEBUG
1771 struct tun_struct *tun = netdev_priv(dev);
1772 tun->debug = value;
1773 #endif
1774 }
1775
1776 static const struct ethtool_ops tun_ethtool_ops = {
1777 .get_settings = tun_get_settings,
1778 .get_drvinfo = tun_get_drvinfo,
1779 .get_msglevel = tun_get_msglevel,
1780 .set_msglevel = tun_set_msglevel,
1781 .get_link = ethtool_op_get_link,
1782 };
1783
1784
1785 static int __init tun_init(void)
1786 {
1787 int ret = 0;
1788
1789 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1790 pr_info("%s\n", DRV_COPYRIGHT);
1791
1792 ret = rtnl_link_register(&tun_link_ops);
1793 if (ret) {
1794 pr_err("Can't register link_ops\n");
1795 goto err_linkops;
1796 }
1797
1798 ret = misc_register(&tun_miscdev);
1799 if (ret) {
1800 pr_err("Can't register misc device %d\n", TUN_MINOR);
1801 goto err_misc;
1802 }
1803 return 0;
1804 err_misc:
1805 rtnl_link_unregister(&tun_link_ops);
1806 err_linkops:
1807 return ret;
1808 }
1809
1810 static void tun_cleanup(void)
1811 {
1812 misc_deregister(&tun_miscdev);
1813 rtnl_link_unregister(&tun_link_ops);
1814 }
1815
1816 /* Get an underlying socket object from tun file. Returns error unless file is
1817 * attached to a device. The returned object works like a packet socket, it
1818 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
1819 * holding a reference to the file for as long as the socket is in use. */
1820 struct socket *tun_get_socket(struct file *file)
1821 {
1822 struct tun_struct *tun;
1823 if (file->f_op != &tun_fops)
1824 return ERR_PTR(-EINVAL);
1825 tun = tun_get(file);
1826 if (!tun)
1827 return ERR_PTR(-EBADFD);
1828 tun_put(tun);
1829 return &tun->socket;
1830 }
1831 EXPORT_SYMBOL_GPL(tun_get_socket);
1832
1833 module_init(tun_init);
1834 module_exit(tun_cleanup);
1835 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1836 MODULE_AUTHOR(DRV_COPYRIGHT);
1837 MODULE_LICENSE("GPL");
1838 MODULE_ALIAS_MISCDEV(TUN_MINOR);
1839 MODULE_ALIAS("devname:net/tun");
Linux kernel - Deliverables
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