tun/tap: Fix crashes if open() /dev/net/tun and then poll() it.
[linux-2.6.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 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 DRV_NAME        "tun"
38 #define DRV_VERSION     "1.6"
39 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
40 #define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
41
42 #include <linux/module.h>
43 #include <linux/errno.h>
44 #include <linux/kernel.h>
45 #include <linux/major.h>
46 #include <linux/slab.h>
47 #include <linux/smp_lock.h>
48 #include <linux/poll.h>
49 #include <linux/fcntl.h>
50 #include <linux/init.h>
51 #include <linux/skbuff.h>
52 #include <linux/netdevice.h>
53 #include <linux/etherdevice.h>
54 #include <linux/miscdevice.h>
55 #include <linux/ethtool.h>
56 #include <linux/rtnetlink.h>
57 #include <linux/if.h>
58 #include <linux/if_arp.h>
59 #include <linux/if_ether.h>
60 #include <linux/if_tun.h>
61 #include <linux/crc32.h>
62 #include <linux/nsproxy.h>
63 #include <linux/virtio_net.h>
64 #include <net/net_namespace.h>
65 #include <net/netns/generic.h>
66 #include <net/rtnetlink.h>
67 #include <net/sock.h>
68
69 #include <asm/system.h>
70 #include <asm/uaccess.h>
71
72 /* Uncomment to enable debugging */
73 /* #define TUN_DEBUG 1 */
74
75 #ifdef TUN_DEBUG
76 static int debug;
77
78 #define DBG  if(tun->debug)printk
79 #define DBG1 if(debug==2)printk
80 #else
81 #define DBG( a... )
82 #define DBG1( a... )
83 #endif
84
85 #define FLT_EXACT_COUNT 8
86 struct tap_filter {
87         unsigned int    count;    /* Number of addrs. Zero means disabled */
88         u32             mask[2];  /* Mask of the hashed addrs */
89         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
90 };
91
92 struct tun_file {
93         atomic_t count;
94         struct tun_struct *tun;
95         struct net *net;
96 };
97
98 struct tun_sock;
99
100 struct tun_struct {
101         struct tun_file         *tfile;
102         unsigned int            flags;
103         uid_t                   owner;
104         gid_t                   group;
105
106         struct sk_buff_head     readq;
107
108         struct net_device       *dev;
109         struct fasync_struct    *fasync;
110
111         struct tap_filter       txflt;
112         struct sock             *sk;
113         struct socket           socket;
114
115 #ifdef TUN_DEBUG
116         int debug;
117 #endif
118 };
119
120 struct tun_sock {
121         struct sock             sk;
122         struct tun_struct       *tun;
123 };
124
125 static inline struct tun_sock *tun_sk(struct sock *sk)
126 {
127         return container_of(sk, struct tun_sock, sk);
128 }
129
130 static int tun_attach(struct tun_struct *tun, struct file *file)
131 {
132         struct tun_file *tfile = file->private_data;
133         const struct cred *cred = current_cred();
134         int err;
135
136         ASSERT_RTNL();
137
138         /* Check permissions */
139         if (((tun->owner != -1 && cred->euid != tun->owner) ||
140              (tun->group != -1 && !in_egroup_p(tun->group))) &&
141                 !capable(CAP_NET_ADMIN))
142                 return -EPERM;
143
144         netif_tx_lock_bh(tun->dev);
145
146         err = -EINVAL;
147         if (tfile->tun)
148                 goto out;
149
150         err = -EBUSY;
151         if (tun->tfile)
152                 goto out;
153
154         err = 0;
155         tfile->tun = tun;
156         tun->tfile = tfile;
157         dev_hold(tun->dev);
158         sock_hold(tun->sk);
159         atomic_inc(&tfile->count);
160
161 out:
162         netif_tx_unlock_bh(tun->dev);
163         return err;
164 }
165
166 static void __tun_detach(struct tun_struct *tun)
167 {
168         /* Detach from net device */
169         netif_tx_lock_bh(tun->dev);
170         tun->tfile = NULL;
171         netif_tx_unlock_bh(tun->dev);
172
173         /* Drop read queue */
174         skb_queue_purge(&tun->readq);
175
176         /* Drop the extra count on the net device */
177         dev_put(tun->dev);
178 }
179
180 static void tun_detach(struct tun_struct *tun)
181 {
182         rtnl_lock();
183         __tun_detach(tun);
184         rtnl_unlock();
185 }
186
187 static struct tun_struct *__tun_get(struct tun_file *tfile)
188 {
189         struct tun_struct *tun = NULL;
190
191         if (atomic_inc_not_zero(&tfile->count))
192                 tun = tfile->tun;
193
194         return tun;
195 }
196
197 static struct tun_struct *tun_get(struct file *file)
198 {
199         return __tun_get(file->private_data);
200 }
201
202 static void tun_put(struct tun_struct *tun)
203 {
204         struct tun_file *tfile = tun->tfile;
205
206         if (atomic_dec_and_test(&tfile->count))
207                 tun_detach(tfile->tun);
208 }
209
210 /* TAP filterting */
211 static void addr_hash_set(u32 *mask, const u8 *addr)
212 {
213         int n = ether_crc(ETH_ALEN, addr) >> 26;
214         mask[n >> 5] |= (1 << (n & 31));
215 }
216
217 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
218 {
219         int n = ether_crc(ETH_ALEN, addr) >> 26;
220         return mask[n >> 5] & (1 << (n & 31));
221 }
222
223 static int update_filter(struct tap_filter *filter, void __user *arg)
224 {
225         struct { u8 u[ETH_ALEN]; } *addr;
226         struct tun_filter uf;
227         int err, alen, n, nexact;
228
229         if (copy_from_user(&uf, arg, sizeof(uf)))
230                 return -EFAULT;
231
232         if (!uf.count) {
233                 /* Disabled */
234                 filter->count = 0;
235                 return 0;
236         }
237
238         alen = ETH_ALEN * uf.count;
239         addr = kmalloc(alen, GFP_KERNEL);
240         if (!addr)
241                 return -ENOMEM;
242
243         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
244                 err = -EFAULT;
245                 goto done;
246         }
247
248         /* The filter is updated without holding any locks. Which is
249          * perfectly safe. We disable it first and in the worst
250          * case we'll accept a few undesired packets. */
251         filter->count = 0;
252         wmb();
253
254         /* Use first set of addresses as an exact filter */
255         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
256                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
257
258         nexact = n;
259
260         /* Remaining multicast addresses are hashed,
261          * unicast will leave the filter disabled. */
262         memset(filter->mask, 0, sizeof(filter->mask));
263         for (; n < uf.count; n++) {
264                 if (!is_multicast_ether_addr(addr[n].u)) {
265                         err = 0; /* no filter */
266                         goto done;
267                 }
268                 addr_hash_set(filter->mask, addr[n].u);
269         }
270
271         /* For ALLMULTI just set the mask to all ones.
272          * This overrides the mask populated above. */
273         if ((uf.flags & TUN_FLT_ALLMULTI))
274                 memset(filter->mask, ~0, sizeof(filter->mask));
275
276         /* Now enable the filter */
277         wmb();
278         filter->count = nexact;
279
280         /* Return the number of exact filters */
281         err = nexact;
282
283 done:
284         kfree(addr);
285         return err;
286 }
287
288 /* Returns: 0 - drop, !=0 - accept */
289 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
290 {
291         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
292          * at this point. */
293         struct ethhdr *eh = (struct ethhdr *) skb->data;
294         int i;
295
296         /* Exact match */
297         for (i = 0; i < filter->count; i++)
298                 if (!compare_ether_addr(eh->h_dest, filter->addr[i]))
299                         return 1;
300
301         /* Inexact match (multicast only) */
302         if (is_multicast_ether_addr(eh->h_dest))
303                 return addr_hash_test(filter->mask, eh->h_dest);
304
305         return 0;
306 }
307
308 /*
309  * Checks whether the packet is accepted or not.
310  * Returns: 0 - drop, !=0 - accept
311  */
312 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
313 {
314         if (!filter->count)
315                 return 1;
316
317         return run_filter(filter, skb);
318 }
319
320 /* Network device part of the driver */
321
322 static const struct ethtool_ops tun_ethtool_ops;
323
324 /* Net device detach from fd. */
325 static void tun_net_uninit(struct net_device *dev)
326 {
327         struct tun_struct *tun = netdev_priv(dev);
328         struct tun_file *tfile = tun->tfile;
329
330         /* Inform the methods they need to stop using the dev.
331          */
332         if (tfile) {
333                 wake_up_all(&tun->socket.wait);
334                 if (atomic_dec_and_test(&tfile->count))
335                         __tun_detach(tun);
336         }
337 }
338
339 static void tun_free_netdev(struct net_device *dev)
340 {
341         struct tun_struct *tun = netdev_priv(dev);
342
343         sock_put(tun->sk);
344 }
345
346 /* Net device open. */
347 static int tun_net_open(struct net_device *dev)
348 {
349         netif_start_queue(dev);
350         return 0;
351 }
352
353 /* Net device close. */
354 static int tun_net_close(struct net_device *dev)
355 {
356         netif_stop_queue(dev);
357         return 0;
358 }
359
360 /* Net device start xmit */
361 static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
362 {
363         struct tun_struct *tun = netdev_priv(dev);
364
365         DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
366
367         /* Drop packet if interface is not attached */
368         if (!tun->tfile)
369                 goto drop;
370
371         /* Drop if the filter does not like it.
372          * This is a noop if the filter is disabled.
373          * Filter can be enabled only for the TAP devices. */
374         if (!check_filter(&tun->txflt, skb))
375                 goto drop;
376
377         if (skb_queue_len(&tun->readq) >= dev->tx_queue_len) {
378                 if (!(tun->flags & TUN_ONE_QUEUE)) {
379                         /* Normal queueing mode. */
380                         /* Packet scheduler handles dropping of further packets. */
381                         netif_stop_queue(dev);
382
383                         /* We won't see all dropped packets individually, so overrun
384                          * error is more appropriate. */
385                         dev->stats.tx_fifo_errors++;
386                 } else {
387                         /* Single queue mode.
388                          * Driver handles dropping of all packets itself. */
389                         goto drop;
390                 }
391         }
392
393         /* Enqueue packet */
394         skb_queue_tail(&tun->readq, skb);
395         dev->trans_start = jiffies;
396
397         /* Notify and wake up reader process */
398         if (tun->flags & TUN_FASYNC)
399                 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
400         wake_up_interruptible(&tun->socket.wait);
401         return 0;
402
403 drop:
404         dev->stats.tx_dropped++;
405         kfree_skb(skb);
406         return 0;
407 }
408
409 static void tun_net_mclist(struct net_device *dev)
410 {
411         /*
412          * This callback is supposed to deal with mc filter in
413          * _rx_ path and has nothing to do with the _tx_ path.
414          * In rx path we always accept everything userspace gives us.
415          */
416         return;
417 }
418
419 #define MIN_MTU 68
420 #define MAX_MTU 65535
421
422 static int
423 tun_net_change_mtu(struct net_device *dev, int new_mtu)
424 {
425         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
426                 return -EINVAL;
427         dev->mtu = new_mtu;
428         return 0;
429 }
430
431 static const struct net_device_ops tun_netdev_ops = {
432         .ndo_uninit             = tun_net_uninit,
433         .ndo_open               = tun_net_open,
434         .ndo_stop               = tun_net_close,
435         .ndo_start_xmit         = tun_net_xmit,
436         .ndo_change_mtu         = tun_net_change_mtu,
437 };
438
439 static const struct net_device_ops tap_netdev_ops = {
440         .ndo_uninit             = tun_net_uninit,
441         .ndo_open               = tun_net_open,
442         .ndo_stop               = tun_net_close,
443         .ndo_start_xmit         = tun_net_xmit,
444         .ndo_change_mtu         = tun_net_change_mtu,
445         .ndo_set_multicast_list = tun_net_mclist,
446         .ndo_set_mac_address    = eth_mac_addr,
447         .ndo_validate_addr      = eth_validate_addr,
448 };
449
450 /* Initialize net device. */
451 static void tun_net_init(struct net_device *dev)
452 {
453         struct tun_struct *tun = netdev_priv(dev);
454
455         switch (tun->flags & TUN_TYPE_MASK) {
456         case TUN_TUN_DEV:
457                 dev->netdev_ops = &tun_netdev_ops;
458
459                 /* Point-to-Point TUN Device */
460                 dev->hard_header_len = 0;
461                 dev->addr_len = 0;
462                 dev->mtu = 1500;
463
464                 /* Zero header length */
465                 dev->type = ARPHRD_NONE;
466                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
467                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
468                 break;
469
470         case TUN_TAP_DEV:
471                 dev->netdev_ops = &tap_netdev_ops;
472                 /* Ethernet TAP Device */
473                 ether_setup(dev);
474
475                 random_ether_addr(dev->dev_addr);
476
477                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
478                 break;
479         }
480 }
481
482 /* Character device part */
483
484 /* Poll */
485 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
486 {
487         struct tun_file *tfile = file->private_data;
488         struct tun_struct *tun = __tun_get(tfile);
489         struct sock *sk;
490         unsigned int mask = 0;
491
492         if (!tun)
493                 return POLLERR;
494
495         sk = tun->sk;
496
497         DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
498
499         poll_wait(file, &tun->socket.wait, wait);
500
501         if (!skb_queue_empty(&tun->readq))
502                 mask |= POLLIN | POLLRDNORM;
503
504         if (sock_writeable(sk) ||
505             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
506              sock_writeable(sk)))
507                 mask |= POLLOUT | POLLWRNORM;
508
509         if (tun->dev->reg_state != NETREG_REGISTERED)
510                 mask = POLLERR;
511
512         tun_put(tun);
513         return mask;
514 }
515
516 /* prepad is the amount to reserve at front.  len is length after that.
517  * linear is a hint as to how much to copy (usually headers). */
518 static inline struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
519                                             size_t prepad, size_t len,
520                                             size_t linear, int noblock)
521 {
522         struct sock *sk = tun->sk;
523         struct sk_buff *skb;
524         int err;
525
526         /* Under a page?  Don't bother with paged skb. */
527         if (prepad + len < PAGE_SIZE || !linear)
528                 linear = len;
529
530         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
531                                    &err);
532         if (!skb)
533                 return ERR_PTR(err);
534
535         skb_reserve(skb, prepad);
536         skb_put(skb, linear);
537         skb->data_len = len - linear;
538         skb->len += len - linear;
539
540         return skb;
541 }
542
543 /* Get packet from user space buffer */
544 static __inline__ ssize_t tun_get_user(struct tun_struct *tun,
545                                        const struct iovec *iv, size_t count,
546                                        int noblock)
547 {
548         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
549         struct sk_buff *skb;
550         size_t len = count, align = 0;
551         struct virtio_net_hdr gso = { 0 };
552         int offset = 0;
553
554         if (!(tun->flags & TUN_NO_PI)) {
555                 if ((len -= sizeof(pi)) > count)
556                         return -EINVAL;
557
558                 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
559                         return -EFAULT;
560                 offset += sizeof(pi);
561         }
562
563         if (tun->flags & TUN_VNET_HDR) {
564                 if ((len -= sizeof(gso)) > count)
565                         return -EINVAL;
566
567                 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
568                         return -EFAULT;
569
570                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
571                     gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
572                         gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
573
574                 if (gso.hdr_len > len)
575                         return -EINVAL;
576                 offset += sizeof(gso);
577         }
578
579         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
580                 align = NET_IP_ALIGN;
581                 if (unlikely(len < ETH_HLEN ||
582                              (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
583                         return -EINVAL;
584         }
585
586         skb = tun_alloc_skb(tun, align, len, gso.hdr_len, noblock);
587         if (IS_ERR(skb)) {
588                 if (PTR_ERR(skb) != -EAGAIN)
589                         tun->dev->stats.rx_dropped++;
590                 return PTR_ERR(skb);
591         }
592
593         if (skb_copy_datagram_from_iovec(skb, 0, iv, offset, len)) {
594                 tun->dev->stats.rx_dropped++;
595                 kfree_skb(skb);
596                 return -EFAULT;
597         }
598
599         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
600                 if (!skb_partial_csum_set(skb, gso.csum_start,
601                                           gso.csum_offset)) {
602                         tun->dev->stats.rx_frame_errors++;
603                         kfree_skb(skb);
604                         return -EINVAL;
605                 }
606         } else if (tun->flags & TUN_NOCHECKSUM)
607                 skb->ip_summed = CHECKSUM_UNNECESSARY;
608
609         switch (tun->flags & TUN_TYPE_MASK) {
610         case TUN_TUN_DEV:
611                 if (tun->flags & TUN_NO_PI) {
612                         switch (skb->data[0] & 0xf0) {
613                         case 0x40:
614                                 pi.proto = htons(ETH_P_IP);
615                                 break;
616                         case 0x60:
617                                 pi.proto = htons(ETH_P_IPV6);
618                                 break;
619                         default:
620                                 tun->dev->stats.rx_dropped++;
621                                 kfree_skb(skb);
622                                 return -EINVAL;
623                         }
624                 }
625
626                 skb_reset_mac_header(skb);
627                 skb->protocol = pi.proto;
628                 skb->dev = tun->dev;
629                 break;
630         case TUN_TAP_DEV:
631                 skb->protocol = eth_type_trans(skb, tun->dev);
632                 break;
633         };
634
635         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
636                 pr_debug("GSO!\n");
637                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
638                 case VIRTIO_NET_HDR_GSO_TCPV4:
639                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
640                         break;
641                 case VIRTIO_NET_HDR_GSO_TCPV6:
642                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
643                         break;
644                 default:
645                         tun->dev->stats.rx_frame_errors++;
646                         kfree_skb(skb);
647                         return -EINVAL;
648                 }
649
650                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
651                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
652
653                 skb_shinfo(skb)->gso_size = gso.gso_size;
654                 if (skb_shinfo(skb)->gso_size == 0) {
655                         tun->dev->stats.rx_frame_errors++;
656                         kfree_skb(skb);
657                         return -EINVAL;
658                 }
659
660                 /* Header must be checked, and gso_segs computed. */
661                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
662                 skb_shinfo(skb)->gso_segs = 0;
663         }
664
665         netif_rx_ni(skb);
666
667         tun->dev->stats.rx_packets++;
668         tun->dev->stats.rx_bytes += len;
669
670         return count;
671 }
672
673 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
674                               unsigned long count, loff_t pos)
675 {
676         struct file *file = iocb->ki_filp;
677         struct tun_struct *tun = tun_get(file);
678         ssize_t result;
679
680         if (!tun)
681                 return -EBADFD;
682
683         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
684
685         result = tun_get_user(tun, iv, iov_length(iv, count),
686                               file->f_flags & O_NONBLOCK);
687
688         tun_put(tun);
689         return result;
690 }
691
692 /* Put packet to the user space buffer */
693 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
694                                        struct sk_buff *skb,
695                                        const struct iovec *iv, int len)
696 {
697         struct tun_pi pi = { 0, skb->protocol };
698         ssize_t total = 0;
699
700         if (!(tun->flags & TUN_NO_PI)) {
701                 if ((len -= sizeof(pi)) < 0)
702                         return -EINVAL;
703
704                 if (len < skb->len) {
705                         /* Packet will be striped */
706                         pi.flags |= TUN_PKT_STRIP;
707                 }
708
709                 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
710                         return -EFAULT;
711                 total += sizeof(pi);
712         }
713
714         if (tun->flags & TUN_VNET_HDR) {
715                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
716                 if ((len -= sizeof(gso)) < 0)
717                         return -EINVAL;
718
719                 if (skb_is_gso(skb)) {
720                         struct skb_shared_info *sinfo = skb_shinfo(skb);
721
722                         /* This is a hint as to how much should be linear. */
723                         gso.hdr_len = skb_headlen(skb);
724                         gso.gso_size = sinfo->gso_size;
725                         if (sinfo->gso_type & SKB_GSO_TCPV4)
726                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
727                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
728                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
729                         else
730                                 BUG();
731                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
732                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
733                 } else
734                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
735
736                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
737                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
738                         gso.csum_start = skb->csum_start - skb_headroom(skb);
739                         gso.csum_offset = skb->csum_offset;
740                 } /* else everything is zero */
741
742                 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
743                                                sizeof(gso))))
744                         return -EFAULT;
745                 total += sizeof(gso);
746         }
747
748         len = min_t(int, skb->len, len);
749
750         skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
751         total += len;
752
753         tun->dev->stats.tx_packets++;
754         tun->dev->stats.tx_bytes += len;
755
756         return total;
757 }
758
759 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
760                             unsigned long count, loff_t pos)
761 {
762         struct file *file = iocb->ki_filp;
763         struct tun_file *tfile = file->private_data;
764         struct tun_struct *tun = __tun_get(tfile);
765         DECLARE_WAITQUEUE(wait, current);
766         struct sk_buff *skb;
767         ssize_t len, ret = 0;
768
769         if (!tun)
770                 return -EBADFD;
771
772         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
773
774         len = iov_length(iv, count);
775         if (len < 0) {
776                 ret = -EINVAL;
777                 goto out;
778         }
779
780         add_wait_queue(&tun->socket.wait, &wait);
781         while (len) {
782                 current->state = TASK_INTERRUPTIBLE;
783
784                 /* Read frames from the queue */
785                 if (!(skb=skb_dequeue(&tun->readq))) {
786                         if (file->f_flags & O_NONBLOCK) {
787                                 ret = -EAGAIN;
788                                 break;
789                         }
790                         if (signal_pending(current)) {
791                                 ret = -ERESTARTSYS;
792                                 break;
793                         }
794                         if (tun->dev->reg_state != NETREG_REGISTERED) {
795                                 ret = -EIO;
796                                 break;
797                         }
798
799                         /* Nothing to read, let's sleep */
800                         schedule();
801                         continue;
802                 }
803                 netif_wake_queue(tun->dev);
804
805                 ret = tun_put_user(tun, skb, iv, len);
806                 kfree_skb(skb);
807                 break;
808         }
809
810         current->state = TASK_RUNNING;
811         remove_wait_queue(&tun->socket.wait, &wait);
812
813 out:
814         tun_put(tun);
815         return ret;
816 }
817
818 static void tun_setup(struct net_device *dev)
819 {
820         struct tun_struct *tun = netdev_priv(dev);
821
822         skb_queue_head_init(&tun->readq);
823
824         tun->owner = -1;
825         tun->group = -1;
826
827         dev->ethtool_ops = &tun_ethtool_ops;
828         dev->destructor = tun_free_netdev;
829 }
830
831 /* Trivial set of netlink ops to allow deleting tun or tap
832  * device with netlink.
833  */
834 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
835 {
836         return -EINVAL;
837 }
838
839 static struct rtnl_link_ops tun_link_ops __read_mostly = {
840         .kind           = DRV_NAME,
841         .priv_size      = sizeof(struct tun_struct),
842         .setup          = tun_setup,
843         .validate       = tun_validate,
844 };
845
846 static void tun_sock_write_space(struct sock *sk)
847 {
848         struct tun_struct *tun;
849
850         if (!sock_writeable(sk))
851                 return;
852
853         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
854                 return;
855
856         if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
857                 wake_up_interruptible_sync(sk->sk_sleep);
858
859         tun = container_of(sk, struct tun_sock, sk)->tun;
860         kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
861 }
862
863 static void tun_sock_destruct(struct sock *sk)
864 {
865         free_netdev(container_of(sk, struct tun_sock, sk)->tun->dev);
866 }
867
868 static struct proto tun_proto = {
869         .name           = "tun",
870         .owner          = THIS_MODULE,
871         .obj_size       = sizeof(struct tun_sock),
872 };
873
874 static int tun_flags(struct tun_struct *tun)
875 {
876         int flags = 0;
877
878         if (tun->flags & TUN_TUN_DEV)
879                 flags |= IFF_TUN;
880         else
881                 flags |= IFF_TAP;
882
883         if (tun->flags & TUN_NO_PI)
884                 flags |= IFF_NO_PI;
885
886         if (tun->flags & TUN_ONE_QUEUE)
887                 flags |= IFF_ONE_QUEUE;
888
889         if (tun->flags & TUN_VNET_HDR)
890                 flags |= IFF_VNET_HDR;
891
892         return flags;
893 }
894
895 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
896                               char *buf)
897 {
898         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
899         return sprintf(buf, "0x%x\n", tun_flags(tun));
900 }
901
902 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
903                               char *buf)
904 {
905         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
906         return sprintf(buf, "%d\n", tun->owner);
907 }
908
909 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
910                               char *buf)
911 {
912         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
913         return sprintf(buf, "%d\n", tun->group);
914 }
915
916 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
917 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
918 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
919
920 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
921 {
922         struct sock *sk;
923         struct tun_struct *tun;
924         struct net_device *dev;
925         int err;
926
927         dev = __dev_get_by_name(net, ifr->ifr_name);
928         if (dev) {
929                 if (ifr->ifr_flags & IFF_TUN_EXCL)
930                         return -EBUSY;
931                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
932                         tun = netdev_priv(dev);
933                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
934                         tun = netdev_priv(dev);
935                 else
936                         return -EINVAL;
937
938                 err = tun_attach(tun, file);
939                 if (err < 0)
940                         return err;
941         }
942         else {
943                 char *name;
944                 unsigned long flags = 0;
945
946                 err = -EINVAL;
947
948                 if (!capable(CAP_NET_ADMIN))
949                         return -EPERM;
950
951                 /* Set dev type */
952                 if (ifr->ifr_flags & IFF_TUN) {
953                         /* TUN device */
954                         flags |= TUN_TUN_DEV;
955                         name = "tun%d";
956                 } else if (ifr->ifr_flags & IFF_TAP) {
957                         /* TAP device */
958                         flags |= TUN_TAP_DEV;
959                         name = "tap%d";
960                 } else
961                         goto failed;
962
963                 if (*ifr->ifr_name)
964                         name = ifr->ifr_name;
965
966                 dev = alloc_netdev(sizeof(struct tun_struct), name,
967                                    tun_setup);
968                 if (!dev)
969                         return -ENOMEM;
970
971                 dev_net_set(dev, net);
972                 dev->rtnl_link_ops = &tun_link_ops;
973
974                 tun = netdev_priv(dev);
975                 tun->dev = dev;
976                 tun->flags = flags;
977                 tun->txflt.count = 0;
978
979                 err = -ENOMEM;
980                 sk = sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
981                 if (!sk)
982                         goto err_free_dev;
983
984                 init_waitqueue_head(&tun->socket.wait);
985                 sock_init_data(&tun->socket, sk);
986                 sk->sk_write_space = tun_sock_write_space;
987                 sk->sk_sndbuf = INT_MAX;
988
989                 tun->sk = sk;
990                 container_of(sk, struct tun_sock, sk)->tun = tun;
991
992                 tun_net_init(dev);
993
994                 if (strchr(dev->name, '%')) {
995                         err = dev_alloc_name(dev, dev->name);
996                         if (err < 0)
997                                 goto err_free_sk;
998                 }
999
1000                 err = -EINVAL;
1001                 err = register_netdevice(tun->dev);
1002                 if (err < 0)
1003                         goto err_free_sk;
1004
1005                 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1006                     device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1007                     device_create_file(&tun->dev->dev, &dev_attr_group))
1008                         printk(KERN_ERR "Failed to create tun sysfs files\n");
1009
1010                 sk->sk_destruct = tun_sock_destruct;
1011
1012                 err = tun_attach(tun, file);
1013                 if (err < 0)
1014                         goto failed;
1015         }
1016
1017         DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
1018
1019         if (ifr->ifr_flags & IFF_NO_PI)
1020                 tun->flags |= TUN_NO_PI;
1021         else
1022                 tun->flags &= ~TUN_NO_PI;
1023
1024         if (ifr->ifr_flags & IFF_ONE_QUEUE)
1025                 tun->flags |= TUN_ONE_QUEUE;
1026         else
1027                 tun->flags &= ~TUN_ONE_QUEUE;
1028
1029         if (ifr->ifr_flags & IFF_VNET_HDR)
1030                 tun->flags |= TUN_VNET_HDR;
1031         else
1032                 tun->flags &= ~TUN_VNET_HDR;
1033
1034         /* Make sure persistent devices do not get stuck in
1035          * xoff state.
1036          */
1037         if (netif_running(tun->dev))
1038                 netif_wake_queue(tun->dev);
1039
1040         strcpy(ifr->ifr_name, tun->dev->name);
1041         return 0;
1042
1043  err_free_sk:
1044         sock_put(sk);
1045  err_free_dev:
1046         free_netdev(dev);
1047  failed:
1048         return err;
1049 }
1050
1051 static int tun_get_iff(struct net *net, struct file *file, struct ifreq *ifr)
1052 {
1053         struct tun_struct *tun = tun_get(file);
1054
1055         if (!tun)
1056                 return -EBADFD;
1057
1058         DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
1059
1060         strcpy(ifr->ifr_name, tun->dev->name);
1061
1062         ifr->ifr_flags = tun_flags(tun);
1063
1064         tun_put(tun);
1065         return 0;
1066 }
1067
1068 /* This is like a cut-down ethtool ops, except done via tun fd so no
1069  * privs required. */
1070 static int set_offload(struct net_device *dev, unsigned long arg)
1071 {
1072         unsigned int old_features, features;
1073
1074         old_features = dev->features;
1075         /* Unset features, set them as we chew on the arg. */
1076         features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
1077                                     |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6));
1078
1079         if (arg & TUN_F_CSUM) {
1080                 features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1081                 arg &= ~TUN_F_CSUM;
1082
1083                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1084                         if (arg & TUN_F_TSO_ECN) {
1085                                 features |= NETIF_F_TSO_ECN;
1086                                 arg &= ~TUN_F_TSO_ECN;
1087                         }
1088                         if (arg & TUN_F_TSO4)
1089                                 features |= NETIF_F_TSO;
1090                         if (arg & TUN_F_TSO6)
1091                                 features |= NETIF_F_TSO6;
1092                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1093                 }
1094         }
1095
1096         /* This gives the user a way to test for new features in future by
1097          * trying to set them. */
1098         if (arg)
1099                 return -EINVAL;
1100
1101         dev->features = features;
1102         if (old_features != dev->features)
1103                 netdev_features_change(dev);
1104
1105         return 0;
1106 }
1107
1108 static int tun_chr_ioctl(struct inode *inode, struct file *file,
1109                          unsigned int cmd, unsigned long arg)
1110 {
1111         struct tun_file *tfile = file->private_data;
1112         struct tun_struct *tun;
1113         void __user* argp = (void __user*)arg;
1114         struct ifreq ifr;
1115         int sndbuf;
1116         int ret;
1117
1118         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
1119                 if (copy_from_user(&ifr, argp, sizeof ifr))
1120                         return -EFAULT;
1121
1122         if (cmd == TUNGETFEATURES) {
1123                 /* Currently this just means: "what IFF flags are valid?".
1124                  * This is needed because we never checked for invalid flags on
1125                  * TUNSETIFF. */
1126                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1127                                 IFF_VNET_HDR,
1128                                 (unsigned int __user*)argp);
1129         }
1130
1131         tun = __tun_get(tfile);
1132         if (cmd == TUNSETIFF && !tun) {
1133                 int err;
1134
1135                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1136
1137                 rtnl_lock();
1138                 err = tun_set_iff(tfile->net, file, &ifr);
1139                 rtnl_unlock();
1140
1141                 if (err)
1142                         return err;
1143
1144                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
1145                         return -EFAULT;
1146                 return 0;
1147         }
1148
1149
1150         if (!tun)
1151                 return -EBADFD;
1152
1153         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
1154
1155         ret = 0;
1156         switch (cmd) {
1157         case TUNGETIFF:
1158                 ret = tun_get_iff(current->nsproxy->net_ns, file, &ifr);
1159                 if (ret)
1160                         break;
1161
1162                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
1163                         ret = -EFAULT;
1164                 break;
1165
1166         case TUNSETNOCSUM:
1167                 /* Disable/Enable checksum */
1168                 if (arg)
1169                         tun->flags |= TUN_NOCHECKSUM;
1170                 else
1171                         tun->flags &= ~TUN_NOCHECKSUM;
1172
1173                 DBG(KERN_INFO "%s: checksum %s\n",
1174                     tun->dev->name, arg ? "disabled" : "enabled");
1175                 break;
1176
1177         case TUNSETPERSIST:
1178                 /* Disable/Enable persist mode */
1179                 if (arg)
1180                         tun->flags |= TUN_PERSIST;
1181                 else
1182                         tun->flags &= ~TUN_PERSIST;
1183
1184                 DBG(KERN_INFO "%s: persist %s\n",
1185                     tun->dev->name, arg ? "enabled" : "disabled");
1186                 break;
1187
1188         case TUNSETOWNER:
1189                 /* Set owner of the device */
1190                 tun->owner = (uid_t) arg;
1191
1192                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
1193                 break;
1194
1195         case TUNSETGROUP:
1196                 /* Set group of the device */
1197                 tun->group= (gid_t) arg;
1198
1199                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
1200                 break;
1201
1202         case TUNSETLINK:
1203                 /* Only allow setting the type when the interface is down */
1204                 rtnl_lock();
1205                 if (tun->dev->flags & IFF_UP) {
1206                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
1207                                 tun->dev->name);
1208                         ret = -EBUSY;
1209                 } else {
1210                         tun->dev->type = (int) arg;
1211                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
1212                         ret = 0;
1213                 }
1214                 rtnl_unlock();
1215                 break;
1216
1217 #ifdef TUN_DEBUG
1218         case TUNSETDEBUG:
1219                 tun->debug = arg;
1220                 break;
1221 #endif
1222         case TUNSETOFFLOAD:
1223                 rtnl_lock();
1224                 ret = set_offload(tun->dev, arg);
1225                 rtnl_unlock();
1226                 break;
1227
1228         case TUNSETTXFILTER:
1229                 /* Can be set only for TAPs */
1230                 ret = -EINVAL;
1231                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1232                         break;
1233                 rtnl_lock();
1234                 ret = update_filter(&tun->txflt, (void __user *)arg);
1235                 rtnl_unlock();
1236                 break;
1237
1238         case SIOCGIFHWADDR:
1239                 /* Get hw addres */
1240                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1241                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1242                 if (copy_to_user(argp, &ifr, sizeof ifr))
1243                         ret = -EFAULT;
1244                 break;
1245
1246         case SIOCSIFHWADDR:
1247                 /* Set hw address */
1248                 DBG(KERN_DEBUG "%s: set hw address: %pM\n",
1249                         tun->dev->name, ifr.ifr_hwaddr.sa_data);
1250
1251                 rtnl_lock();
1252                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1253                 rtnl_unlock();
1254                 break;
1255
1256         case TUNGETSNDBUF:
1257                 sndbuf = tun->sk->sk_sndbuf;
1258                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1259                         ret = -EFAULT;
1260                 break;
1261
1262         case TUNSETSNDBUF:
1263                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1264                         ret = -EFAULT;
1265                         break;
1266                 }
1267
1268                 tun->sk->sk_sndbuf = sndbuf;
1269                 break;
1270
1271         default:
1272                 ret = -EINVAL;
1273                 break;
1274         };
1275
1276         tun_put(tun);
1277         return ret;
1278 }
1279
1280 static int tun_chr_fasync(int fd, struct file *file, int on)
1281 {
1282         struct tun_struct *tun = tun_get(file);
1283         int ret;
1284
1285         if (!tun)
1286                 return -EBADFD;
1287
1288         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
1289
1290         lock_kernel();
1291         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1292                 goto out;
1293
1294         if (on) {
1295                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1296                 if (ret)
1297                         goto out;
1298                 tun->flags |= TUN_FASYNC;
1299         } else
1300                 tun->flags &= ~TUN_FASYNC;
1301         ret = 0;
1302 out:
1303         unlock_kernel();
1304         tun_put(tun);
1305         return ret;
1306 }
1307
1308 static int tun_chr_open(struct inode *inode, struct file * file)
1309 {
1310         struct tun_file *tfile;
1311         cycle_kernel_lock();
1312         DBG1(KERN_INFO "tunX: tun_chr_open\n");
1313
1314         tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1315         if (!tfile)
1316                 return -ENOMEM;
1317         atomic_set(&tfile->count, 0);
1318         tfile->tun = NULL;
1319         tfile->net = get_net(current->nsproxy->net_ns);
1320         file->private_data = tfile;
1321         return 0;
1322 }
1323
1324 static int tun_chr_close(struct inode *inode, struct file *file)
1325 {
1326         struct tun_file *tfile = file->private_data;
1327         struct tun_struct *tun;
1328
1329         tun = __tun_get(tfile);
1330         if (tun) {
1331                 struct net_device *dev = tun->dev;
1332
1333                 DBG(KERN_INFO "%s: tun_chr_close\n", dev->name);
1334
1335                 __tun_detach(tun);
1336
1337                 /* If desireable, unregister the netdevice. */
1338                 if (!(tun->flags & TUN_PERSIST)) {
1339                         rtnl_lock();
1340                         if (dev->reg_state == NETREG_REGISTERED)
1341                                 unregister_netdevice(dev);
1342                         rtnl_unlock();
1343                 }
1344         }
1345
1346         tun = tfile->tun;
1347         if (tun)
1348                 sock_put(tun->sk);
1349
1350         put_net(tfile->net);
1351         kfree(tfile);
1352
1353         return 0;
1354 }
1355
1356 static const struct file_operations tun_fops = {
1357         .owner  = THIS_MODULE,
1358         .llseek = no_llseek,
1359         .read  = do_sync_read,
1360         .aio_read  = tun_chr_aio_read,
1361         .write = do_sync_write,
1362         .aio_write = tun_chr_aio_write,
1363         .poll   = tun_chr_poll,
1364         .ioctl  = tun_chr_ioctl,
1365         .open   = tun_chr_open,
1366         .release = tun_chr_close,
1367         .fasync = tun_chr_fasync
1368 };
1369
1370 static struct miscdevice tun_miscdev = {
1371         .minor = TUN_MINOR,
1372         .name = "tun",
1373         .devnode = "net/tun",
1374         .fops = &tun_fops,
1375 };
1376
1377 /* ethtool interface */
1378
1379 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1380 {
1381         cmd->supported          = 0;
1382         cmd->advertising        = 0;
1383         cmd->speed              = SPEED_10;
1384         cmd->duplex             = DUPLEX_FULL;
1385         cmd->port               = PORT_TP;
1386         cmd->phy_address        = 0;
1387         cmd->transceiver        = XCVR_INTERNAL;
1388         cmd->autoneg            = AUTONEG_DISABLE;
1389         cmd->maxtxpkt           = 0;
1390         cmd->maxrxpkt           = 0;
1391         return 0;
1392 }
1393
1394 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1395 {
1396         struct tun_struct *tun = netdev_priv(dev);
1397
1398         strcpy(info->driver, DRV_NAME);
1399         strcpy(info->version, DRV_VERSION);
1400         strcpy(info->fw_version, "N/A");
1401
1402         switch (tun->flags & TUN_TYPE_MASK) {
1403         case TUN_TUN_DEV:
1404                 strcpy(info->bus_info, "tun");
1405                 break;
1406         case TUN_TAP_DEV:
1407                 strcpy(info->bus_info, "tap");
1408                 break;
1409         }
1410 }
1411
1412 static u32 tun_get_msglevel(struct net_device *dev)
1413 {
1414 #ifdef TUN_DEBUG
1415         struct tun_struct *tun = netdev_priv(dev);
1416         return tun->debug;
1417 #else
1418         return -EOPNOTSUPP;
1419 #endif
1420 }
1421
1422 static void tun_set_msglevel(struct net_device *dev, u32 value)
1423 {
1424 #ifdef TUN_DEBUG
1425         struct tun_struct *tun = netdev_priv(dev);
1426         tun->debug = value;
1427 #endif
1428 }
1429
1430 static u32 tun_get_link(struct net_device *dev)
1431 {
1432         struct tun_struct *tun = netdev_priv(dev);
1433         return !!tun->tfile;
1434 }
1435
1436 static u32 tun_get_rx_csum(struct net_device *dev)
1437 {
1438         struct tun_struct *tun = netdev_priv(dev);
1439         return (tun->flags & TUN_NOCHECKSUM) == 0;
1440 }
1441
1442 static int tun_set_rx_csum(struct net_device *dev, u32 data)
1443 {
1444         struct tun_struct *tun = netdev_priv(dev);
1445         if (data)
1446                 tun->flags &= ~TUN_NOCHECKSUM;
1447         else
1448                 tun->flags |= TUN_NOCHECKSUM;
1449         return 0;
1450 }
1451
1452 static const struct ethtool_ops tun_ethtool_ops = {
1453         .get_settings   = tun_get_settings,
1454         .get_drvinfo    = tun_get_drvinfo,
1455         .get_msglevel   = tun_get_msglevel,
1456         .set_msglevel   = tun_set_msglevel,
1457         .get_link       = tun_get_link,
1458         .get_rx_csum    = tun_get_rx_csum,
1459         .set_rx_csum    = tun_set_rx_csum
1460 };
1461
1462
1463 static int __init tun_init(void)
1464 {
1465         int ret = 0;
1466
1467         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1468         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
1469
1470         ret = rtnl_link_register(&tun_link_ops);
1471         if (ret) {
1472                 printk(KERN_ERR "tun: Can't register link_ops\n");
1473                 goto err_linkops;
1474         }
1475
1476         ret = misc_register(&tun_miscdev);
1477         if (ret) {
1478                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
1479                 goto err_misc;
1480         }
1481         return  0;
1482 err_misc:
1483         rtnl_link_unregister(&tun_link_ops);
1484 err_linkops:
1485         return ret;
1486 }
1487
1488 static void tun_cleanup(void)
1489 {
1490         misc_deregister(&tun_miscdev);
1491         rtnl_link_unregister(&tun_link_ops);
1492 }
1493
1494 module_init(tun_init);
1495 module_exit(tun_cleanup);
1496 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1497 MODULE_AUTHOR(DRV_COPYRIGHT);
1498 MODULE_LICENSE("GPL");
1499 MODULE_ALIAS_MISCDEV(TUN_MINOR);