CRED: Wrap task credential accesses in the network device drivers
[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
67 #include <asm/system.h>
68 #include <asm/uaccess.h>
69
70 /* Uncomment to enable debugging */
71 /* #define TUN_DEBUG 1 */
72
73 #ifdef TUN_DEBUG
74 static int debug;
75
76 #define DBG  if(tun->debug)printk
77 #define DBG1 if(debug==2)printk
78 #else
79 #define DBG( a... )
80 #define DBG1( a... )
81 #endif
82
83 #define FLT_EXACT_COUNT 8
84 struct tap_filter {
85         unsigned int    count;    /* Number of addrs. Zero means disabled */
86         u32             mask[2];  /* Mask of the hashed addrs */
87         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
88 };
89
90 struct tun_struct {
91         struct list_head        list;
92         unsigned int            flags;
93         int                     attached;
94         uid_t                   owner;
95         gid_t                   group;
96
97         wait_queue_head_t       read_wait;
98         struct sk_buff_head     readq;
99
100         struct net_device       *dev;
101         struct fasync_struct    *fasync;
102
103         struct tap_filter       txflt;
104
105 #ifdef TUN_DEBUG
106         int debug;
107 #endif
108 };
109
110 /* TAP filterting */
111 static void addr_hash_set(u32 *mask, const u8 *addr)
112 {
113         int n = ether_crc(ETH_ALEN, addr) >> 26;
114         mask[n >> 5] |= (1 << (n & 31));
115 }
116
117 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
118 {
119         int n = ether_crc(ETH_ALEN, addr) >> 26;
120         return mask[n >> 5] & (1 << (n & 31));
121 }
122
123 static int update_filter(struct tap_filter *filter, void __user *arg)
124 {
125         struct { u8 u[ETH_ALEN]; } *addr;
126         struct tun_filter uf;
127         int err, alen, n, nexact;
128
129         if (copy_from_user(&uf, arg, sizeof(uf)))
130                 return -EFAULT;
131
132         if (!uf.count) {
133                 /* Disabled */
134                 filter->count = 0;
135                 return 0;
136         }
137
138         alen = ETH_ALEN * uf.count;
139         addr = kmalloc(alen, GFP_KERNEL);
140         if (!addr)
141                 return -ENOMEM;
142
143         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
144                 err = -EFAULT;
145                 goto done;
146         }
147
148         /* The filter is updated without holding any locks. Which is
149          * perfectly safe. We disable it first and in the worst
150          * case we'll accept a few undesired packets. */
151         filter->count = 0;
152         wmb();
153
154         /* Use first set of addresses as an exact filter */
155         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
156                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
157
158         nexact = n;
159
160         /* The rest is hashed */
161         memset(filter->mask, 0, sizeof(filter->mask));
162         for (; n < uf.count; n++)
163                 addr_hash_set(filter->mask, addr[n].u);
164
165         /* For ALLMULTI just set the mask to all ones.
166          * This overrides the mask populated above. */
167         if ((uf.flags & TUN_FLT_ALLMULTI))
168                 memset(filter->mask, ~0, sizeof(filter->mask));
169
170         /* Now enable the filter */
171         wmb();
172         filter->count = nexact;
173
174         /* Return the number of exact filters */
175         err = nexact;
176
177 done:
178         kfree(addr);
179         return err;
180 }
181
182 /* Returns: 0 - drop, !=0 - accept */
183 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
184 {
185         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
186          * at this point. */
187         struct ethhdr *eh = (struct ethhdr *) skb->data;
188         int i;
189
190         /* Exact match */
191         for (i = 0; i < filter->count; i++)
192                 if (!compare_ether_addr(eh->h_dest, filter->addr[i]))
193                         return 1;
194
195         /* Inexact match (multicast only) */
196         if (is_multicast_ether_addr(eh->h_dest))
197                 return addr_hash_test(filter->mask, eh->h_dest);
198
199         return 0;
200 }
201
202 /*
203  * Checks whether the packet is accepted or not.
204  * Returns: 0 - drop, !=0 - accept
205  */
206 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
207 {
208         if (!filter->count)
209                 return 1;
210
211         return run_filter(filter, skb);
212 }
213
214 /* Network device part of the driver */
215
216 static unsigned int tun_net_id;
217 struct tun_net {
218         struct list_head dev_list;
219 };
220
221 static const struct ethtool_ops tun_ethtool_ops;
222
223 /* Net device open. */
224 static int tun_net_open(struct net_device *dev)
225 {
226         netif_start_queue(dev);
227         return 0;
228 }
229
230 /* Net device close. */
231 static int tun_net_close(struct net_device *dev)
232 {
233         netif_stop_queue(dev);
234         return 0;
235 }
236
237 /* Net device start xmit */
238 static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
239 {
240         struct tun_struct *tun = netdev_priv(dev);
241
242         DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
243
244         /* Drop packet if interface is not attached */
245         if (!tun->attached)
246                 goto drop;
247
248         /* Drop if the filter does not like it.
249          * This is a noop if the filter is disabled.
250          * Filter can be enabled only for the TAP devices. */
251         if (!check_filter(&tun->txflt, skb))
252                 goto drop;
253
254         if (skb_queue_len(&tun->readq) >= dev->tx_queue_len) {
255                 if (!(tun->flags & TUN_ONE_QUEUE)) {
256                         /* Normal queueing mode. */
257                         /* Packet scheduler handles dropping of further packets. */
258                         netif_stop_queue(dev);
259
260                         /* We won't see all dropped packets individually, so overrun
261                          * error is more appropriate. */
262                         dev->stats.tx_fifo_errors++;
263                 } else {
264                         /* Single queue mode.
265                          * Driver handles dropping of all packets itself. */
266                         goto drop;
267                 }
268         }
269
270         /* Enqueue packet */
271         skb_queue_tail(&tun->readq, skb);
272         dev->trans_start = jiffies;
273
274         /* Notify and wake up reader process */
275         if (tun->flags & TUN_FASYNC)
276                 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
277         wake_up_interruptible(&tun->read_wait);
278         return 0;
279
280 drop:
281         dev->stats.tx_dropped++;
282         kfree_skb(skb);
283         return 0;
284 }
285
286 static void tun_net_mclist(struct net_device *dev)
287 {
288         /*
289          * This callback is supposed to deal with mc filter in
290          * _rx_ path and has nothing to do with the _tx_ path.
291          * In rx path we always accept everything userspace gives us.
292          */
293         return;
294 }
295
296 #define MIN_MTU 68
297 #define MAX_MTU 65535
298
299 static int
300 tun_net_change_mtu(struct net_device *dev, int new_mtu)
301 {
302         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
303                 return -EINVAL;
304         dev->mtu = new_mtu;
305         return 0;
306 }
307
308 /* Initialize net device. */
309 static void tun_net_init(struct net_device *dev)
310 {
311         struct tun_struct *tun = netdev_priv(dev);
312
313         switch (tun->flags & TUN_TYPE_MASK) {
314         case TUN_TUN_DEV:
315                 /* Point-to-Point TUN Device */
316                 dev->hard_header_len = 0;
317                 dev->addr_len = 0;
318                 dev->mtu = 1500;
319                 dev->change_mtu = tun_net_change_mtu;
320
321                 /* Zero header length */
322                 dev->type = ARPHRD_NONE;
323                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
324                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
325                 break;
326
327         case TUN_TAP_DEV:
328                 /* Ethernet TAP Device */
329                 ether_setup(dev);
330                 dev->change_mtu         = tun_net_change_mtu;
331                 dev->set_multicast_list = tun_net_mclist;
332
333                 random_ether_addr(dev->dev_addr);
334
335                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
336                 break;
337         }
338 }
339
340 /* Character device part */
341
342 /* Poll */
343 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
344 {
345         struct tun_struct *tun = file->private_data;
346         unsigned int mask = POLLOUT | POLLWRNORM;
347
348         if (!tun)
349                 return -EBADFD;
350
351         DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
352
353         poll_wait(file, &tun->read_wait, wait);
354
355         if (!skb_queue_empty(&tun->readq))
356                 mask |= POLLIN | POLLRDNORM;
357
358         return mask;
359 }
360
361 /* prepad is the amount to reserve at front.  len is length after that.
362  * linear is a hint as to how much to copy (usually headers). */
363 static struct sk_buff *tun_alloc_skb(size_t prepad, size_t len, size_t linear,
364                                      gfp_t gfp)
365 {
366         struct sk_buff *skb;
367         unsigned int i;
368
369         skb = alloc_skb(prepad + len, gfp|__GFP_NOWARN);
370         if (skb) {
371                 skb_reserve(skb, prepad);
372                 skb_put(skb, len);
373                 return skb;
374         }
375
376         /* Under a page?  Don't bother with paged skb. */
377         if (prepad + len < PAGE_SIZE)
378                 return NULL;
379
380         /* Start with a normal skb, and add pages. */
381         skb = alloc_skb(prepad + linear, gfp);
382         if (!skb)
383                 return NULL;
384
385         skb_reserve(skb, prepad);
386         skb_put(skb, linear);
387
388         len -= linear;
389
390         for (i = 0; i < MAX_SKB_FRAGS; i++) {
391                 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
392
393                 f->page = alloc_page(gfp|__GFP_ZERO);
394                 if (!f->page)
395                         break;
396
397                 f->page_offset = 0;
398                 f->size = PAGE_SIZE;
399
400                 skb->data_len += PAGE_SIZE;
401                 skb->len += PAGE_SIZE;
402                 skb->truesize += PAGE_SIZE;
403                 skb_shinfo(skb)->nr_frags++;
404
405                 if (len < PAGE_SIZE) {
406                         len = 0;
407                         break;
408                 }
409                 len -= PAGE_SIZE;
410         }
411
412         /* Too large, or alloc fail? */
413         if (unlikely(len)) {
414                 kfree_skb(skb);
415                 skb = NULL;
416         }
417
418         return skb;
419 }
420
421 /* Get packet from user space buffer */
422 static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
423 {
424         struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
425         struct sk_buff *skb;
426         size_t len = count, align = 0;
427         struct virtio_net_hdr gso = { 0 };
428
429         if (!(tun->flags & TUN_NO_PI)) {
430                 if ((len -= sizeof(pi)) > count)
431                         return -EINVAL;
432
433                 if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
434                         return -EFAULT;
435         }
436
437         if (tun->flags & TUN_VNET_HDR) {
438                 if ((len -= sizeof(gso)) > count)
439                         return -EINVAL;
440
441                 if (memcpy_fromiovec((void *)&gso, iv, sizeof(gso)))
442                         return -EFAULT;
443
444                 if (gso.hdr_len > len)
445                         return -EINVAL;
446         }
447
448         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
449                 align = NET_IP_ALIGN;
450                 if (unlikely(len < ETH_HLEN))
451                         return -EINVAL;
452         }
453
454         if (!(skb = tun_alloc_skb(align, len, gso.hdr_len, GFP_KERNEL))) {
455                 tun->dev->stats.rx_dropped++;
456                 return -ENOMEM;
457         }
458
459         if (skb_copy_datagram_from_iovec(skb, 0, iv, len)) {
460                 tun->dev->stats.rx_dropped++;
461                 kfree_skb(skb);
462                 return -EFAULT;
463         }
464
465         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
466                 if (!skb_partial_csum_set(skb, gso.csum_start,
467                                           gso.csum_offset)) {
468                         tun->dev->stats.rx_frame_errors++;
469                         kfree_skb(skb);
470                         return -EINVAL;
471                 }
472         } else if (tun->flags & TUN_NOCHECKSUM)
473                 skb->ip_summed = CHECKSUM_UNNECESSARY;
474
475         switch (tun->flags & TUN_TYPE_MASK) {
476         case TUN_TUN_DEV:
477                 if (tun->flags & TUN_NO_PI) {
478                         switch (skb->data[0] & 0xf0) {
479                         case 0x40:
480                                 pi.proto = htons(ETH_P_IP);
481                                 break;
482                         case 0x60:
483                                 pi.proto = htons(ETH_P_IPV6);
484                                 break;
485                         default:
486                                 tun->dev->stats.rx_dropped++;
487                                 kfree_skb(skb);
488                                 return -EINVAL;
489                         }
490                 }
491
492                 skb_reset_mac_header(skb);
493                 skb->protocol = pi.proto;
494                 skb->dev = tun->dev;
495                 break;
496         case TUN_TAP_DEV:
497                 skb->protocol = eth_type_trans(skb, tun->dev);
498                 break;
499         };
500
501         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
502                 pr_debug("GSO!\n");
503                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
504                 case VIRTIO_NET_HDR_GSO_TCPV4:
505                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
506                         break;
507                 case VIRTIO_NET_HDR_GSO_TCPV6:
508                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
509                         break;
510                 default:
511                         tun->dev->stats.rx_frame_errors++;
512                         kfree_skb(skb);
513                         return -EINVAL;
514                 }
515
516                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
517                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
518
519                 skb_shinfo(skb)->gso_size = gso.gso_size;
520                 if (skb_shinfo(skb)->gso_size == 0) {
521                         tun->dev->stats.rx_frame_errors++;
522                         kfree_skb(skb);
523                         return -EINVAL;
524                 }
525
526                 /* Header must be checked, and gso_segs computed. */
527                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
528                 skb_shinfo(skb)->gso_segs = 0;
529         }
530
531         netif_rx_ni(skb);
532         tun->dev->last_rx = jiffies;
533
534         tun->dev->stats.rx_packets++;
535         tun->dev->stats.rx_bytes += len;
536
537         return count;
538 }
539
540 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
541                               unsigned long count, loff_t pos)
542 {
543         struct tun_struct *tun = iocb->ki_filp->private_data;
544
545         if (!tun)
546                 return -EBADFD;
547
548         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
549
550         return tun_get_user(tun, (struct iovec *) iv, iov_length(iv, count));
551 }
552
553 /* Put packet to the user space buffer */
554 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
555                                        struct sk_buff *skb,
556                                        struct iovec *iv, int len)
557 {
558         struct tun_pi pi = { 0, skb->protocol };
559         ssize_t total = 0;
560
561         if (!(tun->flags & TUN_NO_PI)) {
562                 if ((len -= sizeof(pi)) < 0)
563                         return -EINVAL;
564
565                 if (len < skb->len) {
566                         /* Packet will be striped */
567                         pi.flags |= TUN_PKT_STRIP;
568                 }
569
570                 if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
571                         return -EFAULT;
572                 total += sizeof(pi);
573         }
574
575         if (tun->flags & TUN_VNET_HDR) {
576                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
577                 if ((len -= sizeof(gso)) < 0)
578                         return -EINVAL;
579
580                 if (skb_is_gso(skb)) {
581                         struct skb_shared_info *sinfo = skb_shinfo(skb);
582
583                         /* This is a hint as to how much should be linear. */
584                         gso.hdr_len = skb_headlen(skb);
585                         gso.gso_size = sinfo->gso_size;
586                         if (sinfo->gso_type & SKB_GSO_TCPV4)
587                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
588                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
589                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
590                         else
591                                 BUG();
592                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
593                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
594                 } else
595                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
596
597                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
598                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
599                         gso.csum_start = skb->csum_start - skb_headroom(skb);
600                         gso.csum_offset = skb->csum_offset;
601                 } /* else everything is zero */
602
603                 if (unlikely(memcpy_toiovec(iv, (void *)&gso, sizeof(gso))))
604                         return -EFAULT;
605                 total += sizeof(gso);
606         }
607
608         len = min_t(int, skb->len, len);
609
610         skb_copy_datagram_iovec(skb, 0, iv, len);
611         total += len;
612
613         tun->dev->stats.tx_packets++;
614         tun->dev->stats.tx_bytes += len;
615
616         return total;
617 }
618
619 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
620                             unsigned long count, loff_t pos)
621 {
622         struct file *file = iocb->ki_filp;
623         struct tun_struct *tun = file->private_data;
624         DECLARE_WAITQUEUE(wait, current);
625         struct sk_buff *skb;
626         ssize_t len, ret = 0;
627
628         if (!tun)
629                 return -EBADFD;
630
631         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
632
633         len = iov_length(iv, count);
634         if (len < 0)
635                 return -EINVAL;
636
637         add_wait_queue(&tun->read_wait, &wait);
638         while (len) {
639                 current->state = TASK_INTERRUPTIBLE;
640
641                 /* Read frames from the queue */
642                 if (!(skb=skb_dequeue(&tun->readq))) {
643                         if (file->f_flags & O_NONBLOCK) {
644                                 ret = -EAGAIN;
645                                 break;
646                         }
647                         if (signal_pending(current)) {
648                                 ret = -ERESTARTSYS;
649                                 break;
650                         }
651
652                         /* Nothing to read, let's sleep */
653                         schedule();
654                         continue;
655                 }
656                 netif_wake_queue(tun->dev);
657
658                 ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
659                 kfree_skb(skb);
660                 break;
661         }
662
663         current->state = TASK_RUNNING;
664         remove_wait_queue(&tun->read_wait, &wait);
665
666         return ret;
667 }
668
669 static void tun_setup(struct net_device *dev)
670 {
671         struct tun_struct *tun = netdev_priv(dev);
672
673         skb_queue_head_init(&tun->readq);
674         init_waitqueue_head(&tun->read_wait);
675
676         tun->owner = -1;
677         tun->group = -1;
678
679         dev->open = tun_net_open;
680         dev->hard_start_xmit = tun_net_xmit;
681         dev->stop = tun_net_close;
682         dev->ethtool_ops = &tun_ethtool_ops;
683         dev->destructor = free_netdev;
684         dev->features |= NETIF_F_NETNS_LOCAL;
685 }
686
687 static struct tun_struct *tun_get_by_name(struct tun_net *tn, const char *name)
688 {
689         struct tun_struct *tun;
690
691         ASSERT_RTNL();
692         list_for_each_entry(tun, &tn->dev_list, list) {
693                 if (!strncmp(tun->dev->name, name, IFNAMSIZ))
694                     return tun;
695         }
696
697         return NULL;
698 }
699
700 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
701 {
702         struct tun_net *tn;
703         struct tun_struct *tun;
704         struct net_device *dev;
705         int err;
706
707         tn = net_generic(net, tun_net_id);
708         tun = tun_get_by_name(tn, ifr->ifr_name);
709         if (tun) {
710                 if (tun->attached)
711                         return -EBUSY;
712
713                 /* Check permissions */
714                 if (((tun->owner != -1 &&
715                       current_euid() != tun->owner) ||
716                      (tun->group != -1 &&
717                       current_egid() != tun->group)) &&
718                      !capable(CAP_NET_ADMIN))
719                         return -EPERM;
720         }
721         else if (__dev_get_by_name(net, ifr->ifr_name))
722                 return -EINVAL;
723         else {
724                 char *name;
725                 unsigned long flags = 0;
726
727                 err = -EINVAL;
728
729                 if (!capable(CAP_NET_ADMIN))
730                         return -EPERM;
731
732                 /* Set dev type */
733                 if (ifr->ifr_flags & IFF_TUN) {
734                         /* TUN device */
735                         flags |= TUN_TUN_DEV;
736                         name = "tun%d";
737                 } else if (ifr->ifr_flags & IFF_TAP) {
738                         /* TAP device */
739                         flags |= TUN_TAP_DEV;
740                         name = "tap%d";
741                 } else
742                         goto failed;
743
744                 if (*ifr->ifr_name)
745                         name = ifr->ifr_name;
746
747                 dev = alloc_netdev(sizeof(struct tun_struct), name,
748                                    tun_setup);
749                 if (!dev)
750                         return -ENOMEM;
751
752                 dev_net_set(dev, net);
753                 tun = netdev_priv(dev);
754                 tun->dev = dev;
755                 tun->flags = flags;
756                 tun->txflt.count = 0;
757
758                 tun_net_init(dev);
759
760                 if (strchr(dev->name, '%')) {
761                         err = dev_alloc_name(dev, dev->name);
762                         if (err < 0)
763                                 goto err_free_dev;
764                 }
765
766                 err = register_netdevice(tun->dev);
767                 if (err < 0)
768                         goto err_free_dev;
769
770                 list_add(&tun->list, &tn->dev_list);
771         }
772
773         DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
774
775         if (ifr->ifr_flags & IFF_NO_PI)
776                 tun->flags |= TUN_NO_PI;
777         else
778                 tun->flags &= ~TUN_NO_PI;
779
780         if (ifr->ifr_flags & IFF_ONE_QUEUE)
781                 tun->flags |= TUN_ONE_QUEUE;
782         else
783                 tun->flags &= ~TUN_ONE_QUEUE;
784
785         if (ifr->ifr_flags & IFF_VNET_HDR)
786                 tun->flags |= TUN_VNET_HDR;
787         else
788                 tun->flags &= ~TUN_VNET_HDR;
789
790         file->private_data = tun;
791         tun->attached = 1;
792         get_net(dev_net(tun->dev));
793
794         /* Make sure persistent devices do not get stuck in
795          * xoff state.
796          */
797         if (netif_running(tun->dev))
798                 netif_wake_queue(tun->dev);
799
800         strcpy(ifr->ifr_name, tun->dev->name);
801         return 0;
802
803  err_free_dev:
804         free_netdev(dev);
805  failed:
806         return err;
807 }
808
809 static int tun_get_iff(struct net *net, struct file *file, struct ifreq *ifr)
810 {
811         struct tun_struct *tun = file->private_data;
812
813         if (!tun)
814                 return -EBADFD;
815
816         DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
817
818         strcpy(ifr->ifr_name, tun->dev->name);
819
820         ifr->ifr_flags = 0;
821
822         if (ifr->ifr_flags & TUN_TUN_DEV)
823                 ifr->ifr_flags |= IFF_TUN;
824         else
825                 ifr->ifr_flags |= IFF_TAP;
826
827         if (tun->flags & TUN_NO_PI)
828                 ifr->ifr_flags |= IFF_NO_PI;
829
830         if (tun->flags & TUN_ONE_QUEUE)
831                 ifr->ifr_flags |= IFF_ONE_QUEUE;
832
833         if (tun->flags & TUN_VNET_HDR)
834                 ifr->ifr_flags |= IFF_VNET_HDR;
835
836         return 0;
837 }
838
839 /* This is like a cut-down ethtool ops, except done via tun fd so no
840  * privs required. */
841 static int set_offload(struct net_device *dev, unsigned long arg)
842 {
843         unsigned int old_features, features;
844
845         old_features = dev->features;
846         /* Unset features, set them as we chew on the arg. */
847         features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
848                                     |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6));
849
850         if (arg & TUN_F_CSUM) {
851                 features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
852                 arg &= ~TUN_F_CSUM;
853
854                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
855                         if (arg & TUN_F_TSO_ECN) {
856                                 features |= NETIF_F_TSO_ECN;
857                                 arg &= ~TUN_F_TSO_ECN;
858                         }
859                         if (arg & TUN_F_TSO4)
860                                 features |= NETIF_F_TSO;
861                         if (arg & TUN_F_TSO6)
862                                 features |= NETIF_F_TSO6;
863                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
864                 }
865         }
866
867         /* This gives the user a way to test for new features in future by
868          * trying to set them. */
869         if (arg)
870                 return -EINVAL;
871
872         dev->features = features;
873         if (old_features != dev->features)
874                 netdev_features_change(dev);
875
876         return 0;
877 }
878
879 static int tun_chr_ioctl(struct inode *inode, struct file *file,
880                          unsigned int cmd, unsigned long arg)
881 {
882         struct tun_struct *tun = file->private_data;
883         void __user* argp = (void __user*)arg;
884         struct ifreq ifr;
885         int ret;
886         DECLARE_MAC_BUF(mac);
887
888         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
889                 if (copy_from_user(&ifr, argp, sizeof ifr))
890                         return -EFAULT;
891
892         if (cmd == TUNSETIFF && !tun) {
893                 int err;
894
895                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
896
897                 rtnl_lock();
898                 err = tun_set_iff(current->nsproxy->net_ns, file, &ifr);
899                 rtnl_unlock();
900
901                 if (err)
902                         return err;
903
904                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
905                         return -EFAULT;
906                 return 0;
907         }
908
909         if (cmd == TUNGETFEATURES) {
910                 /* Currently this just means: "what IFF flags are valid?".
911                  * This is needed because we never checked for invalid flags on
912                  * TUNSETIFF. */
913                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
914                                 IFF_VNET_HDR,
915                                 (unsigned int __user*)argp);
916         }
917
918         if (!tun)
919                 return -EBADFD;
920
921         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
922
923         switch (cmd) {
924         case TUNGETIFF:
925                 ret = tun_get_iff(current->nsproxy->net_ns, file, &ifr);
926                 if (ret)
927                         return ret;
928
929                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
930                         return -EFAULT;
931                 break;
932
933         case TUNSETNOCSUM:
934                 /* Disable/Enable checksum */
935                 if (arg)
936                         tun->flags |= TUN_NOCHECKSUM;
937                 else
938                         tun->flags &= ~TUN_NOCHECKSUM;
939
940                 DBG(KERN_INFO "%s: checksum %s\n",
941                     tun->dev->name, arg ? "disabled" : "enabled");
942                 break;
943
944         case TUNSETPERSIST:
945                 /* Disable/Enable persist mode */
946                 if (arg)
947                         tun->flags |= TUN_PERSIST;
948                 else
949                         tun->flags &= ~TUN_PERSIST;
950
951                 DBG(KERN_INFO "%s: persist %s\n",
952                     tun->dev->name, arg ? "enabled" : "disabled");
953                 break;
954
955         case TUNSETOWNER:
956                 /* Set owner of the device */
957                 tun->owner = (uid_t) arg;
958
959                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
960                 break;
961
962         case TUNSETGROUP:
963                 /* Set group of the device */
964                 tun->group= (gid_t) arg;
965
966                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
967                 break;
968
969         case TUNSETLINK:
970                 /* Only allow setting the type when the interface is down */
971                 rtnl_lock();
972                 if (tun->dev->flags & IFF_UP) {
973                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
974                                 tun->dev->name);
975                         ret = -EBUSY;
976                 } else {
977                         tun->dev->type = (int) arg;
978                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
979                         ret = 0;
980                 }
981                 rtnl_unlock();
982                 return ret;
983
984 #ifdef TUN_DEBUG
985         case TUNSETDEBUG:
986                 tun->debug = arg;
987                 break;
988 #endif
989         case TUNSETOFFLOAD:
990                 rtnl_lock();
991                 ret = set_offload(tun->dev, arg);
992                 rtnl_unlock();
993                 return ret;
994
995         case TUNSETTXFILTER:
996                 /* Can be set only for TAPs */
997                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
998                         return -EINVAL;
999                 rtnl_lock();
1000                 ret = update_filter(&tun->txflt, (void __user *)arg);
1001                 rtnl_unlock();
1002                 return ret;
1003
1004         case SIOCGIFHWADDR:
1005                 /* Get hw addres */
1006                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1007                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1008                 if (copy_to_user(argp, &ifr, sizeof ifr))
1009                         return -EFAULT;
1010                 return 0;
1011
1012         case SIOCSIFHWADDR:
1013                 /* Set hw address */
1014                 DBG(KERN_DEBUG "%s: set hw address: %s\n",
1015                         tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
1016
1017                 rtnl_lock();
1018                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1019                 rtnl_unlock();
1020                 return ret;
1021
1022         default:
1023                 return -EINVAL;
1024         };
1025
1026         return 0;
1027 }
1028
1029 static int tun_chr_fasync(int fd, struct file *file, int on)
1030 {
1031         struct tun_struct *tun = file->private_data;
1032         int ret;
1033
1034         if (!tun)
1035                 return -EBADFD;
1036
1037         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
1038
1039         lock_kernel();
1040         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1041                 goto out;
1042
1043         if (on) {
1044                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1045                 if (ret)
1046                         goto out;
1047                 tun->flags |= TUN_FASYNC;
1048         } else
1049                 tun->flags &= ~TUN_FASYNC;
1050         ret = 0;
1051 out:
1052         unlock_kernel();
1053         return ret;
1054 }
1055
1056 static int tun_chr_open(struct inode *inode, struct file * file)
1057 {
1058         cycle_kernel_lock();
1059         DBG1(KERN_INFO "tunX: tun_chr_open\n");
1060         file->private_data = NULL;
1061         return 0;
1062 }
1063
1064 static int tun_chr_close(struct inode *inode, struct file *file)
1065 {
1066         struct tun_struct *tun = file->private_data;
1067
1068         if (!tun)
1069                 return 0;
1070
1071         DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
1072
1073         rtnl_lock();
1074
1075         /* Detach from net device */
1076         file->private_data = NULL;
1077         tun->attached = 0;
1078         put_net(dev_net(tun->dev));
1079
1080         /* Drop read queue */
1081         skb_queue_purge(&tun->readq);
1082
1083         if (!(tun->flags & TUN_PERSIST)) {
1084                 list_del(&tun->list);
1085                 unregister_netdevice(tun->dev);
1086         }
1087
1088         rtnl_unlock();
1089
1090         return 0;
1091 }
1092
1093 static const struct file_operations tun_fops = {
1094         .owner  = THIS_MODULE,
1095         .llseek = no_llseek,
1096         .read  = do_sync_read,
1097         .aio_read  = tun_chr_aio_read,
1098         .write = do_sync_write,
1099         .aio_write = tun_chr_aio_write,
1100         .poll   = tun_chr_poll,
1101         .ioctl  = tun_chr_ioctl,
1102         .open   = tun_chr_open,
1103         .release = tun_chr_close,
1104         .fasync = tun_chr_fasync
1105 };
1106
1107 static struct miscdevice tun_miscdev = {
1108         .minor = TUN_MINOR,
1109         .name = "tun",
1110         .fops = &tun_fops,
1111 };
1112
1113 /* ethtool interface */
1114
1115 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1116 {
1117         cmd->supported          = 0;
1118         cmd->advertising        = 0;
1119         cmd->speed              = SPEED_10;
1120         cmd->duplex             = DUPLEX_FULL;
1121         cmd->port               = PORT_TP;
1122         cmd->phy_address        = 0;
1123         cmd->transceiver        = XCVR_INTERNAL;
1124         cmd->autoneg            = AUTONEG_DISABLE;
1125         cmd->maxtxpkt           = 0;
1126         cmd->maxrxpkt           = 0;
1127         return 0;
1128 }
1129
1130 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1131 {
1132         struct tun_struct *tun = netdev_priv(dev);
1133
1134         strcpy(info->driver, DRV_NAME);
1135         strcpy(info->version, DRV_VERSION);
1136         strcpy(info->fw_version, "N/A");
1137
1138         switch (tun->flags & TUN_TYPE_MASK) {
1139         case TUN_TUN_DEV:
1140                 strcpy(info->bus_info, "tun");
1141                 break;
1142         case TUN_TAP_DEV:
1143                 strcpy(info->bus_info, "tap");
1144                 break;
1145         }
1146 }
1147
1148 static u32 tun_get_msglevel(struct net_device *dev)
1149 {
1150 #ifdef TUN_DEBUG
1151         struct tun_struct *tun = netdev_priv(dev);
1152         return tun->debug;
1153 #else
1154         return -EOPNOTSUPP;
1155 #endif
1156 }
1157
1158 static void tun_set_msglevel(struct net_device *dev, u32 value)
1159 {
1160 #ifdef TUN_DEBUG
1161         struct tun_struct *tun = netdev_priv(dev);
1162         tun->debug = value;
1163 #endif
1164 }
1165
1166 static u32 tun_get_link(struct net_device *dev)
1167 {
1168         struct tun_struct *tun = netdev_priv(dev);
1169         return tun->attached;
1170 }
1171
1172 static u32 tun_get_rx_csum(struct net_device *dev)
1173 {
1174         struct tun_struct *tun = netdev_priv(dev);
1175         return (tun->flags & TUN_NOCHECKSUM) == 0;
1176 }
1177
1178 static int tun_set_rx_csum(struct net_device *dev, u32 data)
1179 {
1180         struct tun_struct *tun = netdev_priv(dev);
1181         if (data)
1182                 tun->flags &= ~TUN_NOCHECKSUM;
1183         else
1184                 tun->flags |= TUN_NOCHECKSUM;
1185         return 0;
1186 }
1187
1188 static const struct ethtool_ops tun_ethtool_ops = {
1189         .get_settings   = tun_get_settings,
1190         .get_drvinfo    = tun_get_drvinfo,
1191         .get_msglevel   = tun_get_msglevel,
1192         .set_msglevel   = tun_set_msglevel,
1193         .get_link       = tun_get_link,
1194         .get_rx_csum    = tun_get_rx_csum,
1195         .set_rx_csum    = tun_set_rx_csum
1196 };
1197
1198 static int tun_init_net(struct net *net)
1199 {
1200         struct tun_net *tn;
1201
1202         tn = kmalloc(sizeof(*tn), GFP_KERNEL);
1203         if (tn == NULL)
1204                 return -ENOMEM;
1205
1206         INIT_LIST_HEAD(&tn->dev_list);
1207
1208         if (net_assign_generic(net, tun_net_id, tn)) {
1209                 kfree(tn);
1210                 return -ENOMEM;
1211         }
1212
1213         return 0;
1214 }
1215
1216 static void tun_exit_net(struct net *net)
1217 {
1218         struct tun_net *tn;
1219         struct tun_struct *tun, *nxt;
1220
1221         tn = net_generic(net, tun_net_id);
1222
1223         rtnl_lock();
1224         list_for_each_entry_safe(tun, nxt, &tn->dev_list, list) {
1225                 DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
1226                 unregister_netdevice(tun->dev);
1227         }
1228         rtnl_unlock();
1229
1230         kfree(tn);
1231 }
1232
1233 static struct pernet_operations tun_net_ops = {
1234         .init = tun_init_net,
1235         .exit = tun_exit_net,
1236 };
1237
1238 static int __init tun_init(void)
1239 {
1240         int ret = 0;
1241
1242         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1243         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
1244
1245         ret = register_pernet_gen_device(&tun_net_id, &tun_net_ops);
1246         if (ret) {
1247                 printk(KERN_ERR "tun: Can't register pernet ops\n");
1248                 goto err_pernet;
1249         }
1250
1251         ret = misc_register(&tun_miscdev);
1252         if (ret) {
1253                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
1254                 goto err_misc;
1255         }
1256         return 0;
1257
1258 err_misc:
1259         unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
1260 err_pernet:
1261         return ret;
1262 }
1263
1264 static void tun_cleanup(void)
1265 {
1266         misc_deregister(&tun_miscdev);
1267         unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
1268 }
1269
1270 module_init(tun_init);
1271 module_exit(tun_cleanup);
1272 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1273 MODULE_AUTHOR(DRV_COPYRIGHT);
1274 MODULE_LICENSE("GPL");
1275 MODULE_ALIAS_MISCDEV(TUN_MINOR);