Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus
[linux-2.6] / 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         /* Remaining multicast addresses are hashed,
161          * unicast will leave the filter disabled. */
162         memset(filter->mask, 0, sizeof(filter->mask));
163         for (; n < uf.count; n++) {
164                 if (!is_multicast_ether_addr(addr[n].u)) {
165                         err = 0; /* no filter */
166                         goto done;
167                 }
168                 addr_hash_set(filter->mask, addr[n].u);
169         }
170
171         /* For ALLMULTI just set the mask to all ones.
172          * This overrides the mask populated above. */
173         if ((uf.flags & TUN_FLT_ALLMULTI))
174                 memset(filter->mask, ~0, sizeof(filter->mask));
175
176         /* Now enable the filter */
177         wmb();
178         filter->count = nexact;
179
180         /* Return the number of exact filters */
181         err = nexact;
182
183 done:
184         kfree(addr);
185         return err;
186 }
187
188 /* Returns: 0 - drop, !=0 - accept */
189 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
190 {
191         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
192          * at this point. */
193         struct ethhdr *eh = (struct ethhdr *) skb->data;
194         int i;
195
196         /* Exact match */
197         for (i = 0; i < filter->count; i++)
198                 if (!compare_ether_addr(eh->h_dest, filter->addr[i]))
199                         return 1;
200
201         /* Inexact match (multicast only) */
202         if (is_multicast_ether_addr(eh->h_dest))
203                 return addr_hash_test(filter->mask, eh->h_dest);
204
205         return 0;
206 }
207
208 /*
209  * Checks whether the packet is accepted or not.
210  * Returns: 0 - drop, !=0 - accept
211  */
212 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
213 {
214         if (!filter->count)
215                 return 1;
216
217         return run_filter(filter, skb);
218 }
219
220 /* Network device part of the driver */
221
222 static int tun_net_id;
223 struct tun_net {
224         struct list_head dev_list;
225 };
226
227 static const struct ethtool_ops tun_ethtool_ops;
228
229 /* Net device open. */
230 static int tun_net_open(struct net_device *dev)
231 {
232         netif_start_queue(dev);
233         return 0;
234 }
235
236 /* Net device close. */
237 static int tun_net_close(struct net_device *dev)
238 {
239         netif_stop_queue(dev);
240         return 0;
241 }
242
243 /* Net device start xmit */
244 static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
245 {
246         struct tun_struct *tun = netdev_priv(dev);
247
248         DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
249
250         /* Drop packet if interface is not attached */
251         if (!tun->attached)
252                 goto drop;
253
254         /* Drop if the filter does not like it.
255          * This is a noop if the filter is disabled.
256          * Filter can be enabled only for the TAP devices. */
257         if (!check_filter(&tun->txflt, skb))
258                 goto drop;
259
260         if (skb_queue_len(&tun->readq) >= dev->tx_queue_len) {
261                 if (!(tun->flags & TUN_ONE_QUEUE)) {
262                         /* Normal queueing mode. */
263                         /* Packet scheduler handles dropping of further packets. */
264                         netif_stop_queue(dev);
265
266                         /* We won't see all dropped packets individually, so overrun
267                          * error is more appropriate. */
268                         dev->stats.tx_fifo_errors++;
269                 } else {
270                         /* Single queue mode.
271                          * Driver handles dropping of all packets itself. */
272                         goto drop;
273                 }
274         }
275
276         /* Enqueue packet */
277         skb_queue_tail(&tun->readq, skb);
278         dev->trans_start = jiffies;
279
280         /* Notify and wake up reader process */
281         if (tun->flags & TUN_FASYNC)
282                 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
283         wake_up_interruptible(&tun->read_wait);
284         return 0;
285
286 drop:
287         dev->stats.tx_dropped++;
288         kfree_skb(skb);
289         return 0;
290 }
291
292 static void tun_net_mclist(struct net_device *dev)
293 {
294         /*
295          * This callback is supposed to deal with mc filter in
296          * _rx_ path and has nothing to do with the _tx_ path.
297          * In rx path we always accept everything userspace gives us.
298          */
299         return;
300 }
301
302 #define MIN_MTU 68
303 #define MAX_MTU 65535
304
305 static int
306 tun_net_change_mtu(struct net_device *dev, int new_mtu)
307 {
308         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
309                 return -EINVAL;
310         dev->mtu = new_mtu;
311         return 0;
312 }
313
314 static const struct net_device_ops tun_netdev_ops = {
315         .ndo_open               = tun_net_open,
316         .ndo_stop               = tun_net_close,
317         .ndo_start_xmit         = tun_net_xmit,
318         .ndo_change_mtu         = tun_net_change_mtu,
319 };
320
321 static const struct net_device_ops tap_netdev_ops = {
322         .ndo_open               = tun_net_open,
323         .ndo_stop               = tun_net_close,
324         .ndo_start_xmit         = tun_net_xmit,
325         .ndo_change_mtu         = tun_net_change_mtu,
326         .ndo_set_multicast_list = tun_net_mclist,
327         .ndo_set_mac_address    = eth_mac_addr,
328         .ndo_validate_addr      = eth_validate_addr,
329 };
330
331 /* Initialize net device. */
332 static void tun_net_init(struct net_device *dev)
333 {
334         struct tun_struct *tun = netdev_priv(dev);
335
336         switch (tun->flags & TUN_TYPE_MASK) {
337         case TUN_TUN_DEV:
338                 dev->netdev_ops = &tun_netdev_ops;
339
340                 /* Point-to-Point TUN Device */
341                 dev->hard_header_len = 0;
342                 dev->addr_len = 0;
343                 dev->mtu = 1500;
344
345                 /* Zero header length */
346                 dev->type = ARPHRD_NONE;
347                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
348                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
349                 break;
350
351         case TUN_TAP_DEV:
352                 dev->netdev_ops = &tap_netdev_ops;
353                 /* Ethernet TAP Device */
354                 ether_setup(dev);
355
356                 random_ether_addr(dev->dev_addr);
357
358                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
359                 break;
360         }
361 }
362
363 /* Character device part */
364
365 /* Poll */
366 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
367 {
368         struct tun_struct *tun = file->private_data;
369         unsigned int mask = POLLOUT | POLLWRNORM;
370
371         if (!tun)
372                 return -EBADFD;
373
374         DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
375
376         poll_wait(file, &tun->read_wait, wait);
377
378         if (!skb_queue_empty(&tun->readq))
379                 mask |= POLLIN | POLLRDNORM;
380
381         return mask;
382 }
383
384 /* prepad is the amount to reserve at front.  len is length after that.
385  * linear is a hint as to how much to copy (usually headers). */
386 static struct sk_buff *tun_alloc_skb(size_t prepad, size_t len, size_t linear,
387                                      gfp_t gfp)
388 {
389         struct sk_buff *skb;
390         unsigned int i;
391
392         skb = alloc_skb(prepad + len, gfp|__GFP_NOWARN);
393         if (skb) {
394                 skb_reserve(skb, prepad);
395                 skb_put(skb, len);
396                 return skb;
397         }
398
399         /* Under a page?  Don't bother with paged skb. */
400         if (prepad + len < PAGE_SIZE)
401                 return NULL;
402
403         /* Start with a normal skb, and add pages. */
404         skb = alloc_skb(prepad + linear, gfp);
405         if (!skb)
406                 return NULL;
407
408         skb_reserve(skb, prepad);
409         skb_put(skb, linear);
410
411         len -= linear;
412
413         for (i = 0; i < MAX_SKB_FRAGS; i++) {
414                 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
415
416                 f->page = alloc_page(gfp|__GFP_ZERO);
417                 if (!f->page)
418                         break;
419
420                 f->page_offset = 0;
421                 f->size = PAGE_SIZE;
422
423                 skb->data_len += PAGE_SIZE;
424                 skb->len += PAGE_SIZE;
425                 skb->truesize += PAGE_SIZE;
426                 skb_shinfo(skb)->nr_frags++;
427
428                 if (len < PAGE_SIZE) {
429                         len = 0;
430                         break;
431                 }
432                 len -= PAGE_SIZE;
433         }
434
435         /* Too large, or alloc fail? */
436         if (unlikely(len)) {
437                 kfree_skb(skb);
438                 skb = NULL;
439         }
440
441         return skb;
442 }
443
444 /* Get packet from user space buffer */
445 static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
446 {
447         struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
448         struct sk_buff *skb;
449         size_t len = count, align = 0;
450         struct virtio_net_hdr gso = { 0 };
451
452         if (!(tun->flags & TUN_NO_PI)) {
453                 if ((len -= sizeof(pi)) > count)
454                         return -EINVAL;
455
456                 if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
457                         return -EFAULT;
458         }
459
460         if (tun->flags & TUN_VNET_HDR) {
461                 if ((len -= sizeof(gso)) > count)
462                         return -EINVAL;
463
464                 if (memcpy_fromiovec((void *)&gso, iv, sizeof(gso)))
465                         return -EFAULT;
466
467                 if (gso.hdr_len > len)
468                         return -EINVAL;
469         }
470
471         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
472                 align = NET_IP_ALIGN;
473                 if (unlikely(len < ETH_HLEN))
474                         return -EINVAL;
475         }
476
477         if (!(skb = tun_alloc_skb(align, len, gso.hdr_len, GFP_KERNEL))) {
478                 tun->dev->stats.rx_dropped++;
479                 return -ENOMEM;
480         }
481
482         if (skb_copy_datagram_from_iovec(skb, 0, iv, len)) {
483                 tun->dev->stats.rx_dropped++;
484                 kfree_skb(skb);
485                 return -EFAULT;
486         }
487
488         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
489                 if (!skb_partial_csum_set(skb, gso.csum_start,
490                                           gso.csum_offset)) {
491                         tun->dev->stats.rx_frame_errors++;
492                         kfree_skb(skb);
493                         return -EINVAL;
494                 }
495         } else if (tun->flags & TUN_NOCHECKSUM)
496                 skb->ip_summed = CHECKSUM_UNNECESSARY;
497
498         switch (tun->flags & TUN_TYPE_MASK) {
499         case TUN_TUN_DEV:
500                 if (tun->flags & TUN_NO_PI) {
501                         switch (skb->data[0] & 0xf0) {
502                         case 0x40:
503                                 pi.proto = htons(ETH_P_IP);
504                                 break;
505                         case 0x60:
506                                 pi.proto = htons(ETH_P_IPV6);
507                                 break;
508                         default:
509                                 tun->dev->stats.rx_dropped++;
510                                 kfree_skb(skb);
511                                 return -EINVAL;
512                         }
513                 }
514
515                 skb_reset_mac_header(skb);
516                 skb->protocol = pi.proto;
517                 skb->dev = tun->dev;
518                 break;
519         case TUN_TAP_DEV:
520                 skb->protocol = eth_type_trans(skb, tun->dev);
521                 break;
522         };
523
524         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
525                 pr_debug("GSO!\n");
526                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
527                 case VIRTIO_NET_HDR_GSO_TCPV4:
528                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
529                         break;
530                 case VIRTIO_NET_HDR_GSO_TCPV6:
531                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
532                         break;
533                 default:
534                         tun->dev->stats.rx_frame_errors++;
535                         kfree_skb(skb);
536                         return -EINVAL;
537                 }
538
539                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
540                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
541
542                 skb_shinfo(skb)->gso_size = gso.gso_size;
543                 if (skb_shinfo(skb)->gso_size == 0) {
544                         tun->dev->stats.rx_frame_errors++;
545                         kfree_skb(skb);
546                         return -EINVAL;
547                 }
548
549                 /* Header must be checked, and gso_segs computed. */
550                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
551                 skb_shinfo(skb)->gso_segs = 0;
552         }
553
554         netif_rx_ni(skb);
555
556         tun->dev->stats.rx_packets++;
557         tun->dev->stats.rx_bytes += len;
558
559         return count;
560 }
561
562 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
563                               unsigned long count, loff_t pos)
564 {
565         struct tun_struct *tun = iocb->ki_filp->private_data;
566
567         if (!tun)
568                 return -EBADFD;
569
570         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
571
572         return tun_get_user(tun, (struct iovec *) iv, iov_length(iv, count));
573 }
574
575 /* Put packet to the user space buffer */
576 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
577                                        struct sk_buff *skb,
578                                        struct iovec *iv, int len)
579 {
580         struct tun_pi pi = { 0, skb->protocol };
581         ssize_t total = 0;
582
583         if (!(tun->flags & TUN_NO_PI)) {
584                 if ((len -= sizeof(pi)) < 0)
585                         return -EINVAL;
586
587                 if (len < skb->len) {
588                         /* Packet will be striped */
589                         pi.flags |= TUN_PKT_STRIP;
590                 }
591
592                 if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
593                         return -EFAULT;
594                 total += sizeof(pi);
595         }
596
597         if (tun->flags & TUN_VNET_HDR) {
598                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
599                 if ((len -= sizeof(gso)) < 0)
600                         return -EINVAL;
601
602                 if (skb_is_gso(skb)) {
603                         struct skb_shared_info *sinfo = skb_shinfo(skb);
604
605                         /* This is a hint as to how much should be linear. */
606                         gso.hdr_len = skb_headlen(skb);
607                         gso.gso_size = sinfo->gso_size;
608                         if (sinfo->gso_type & SKB_GSO_TCPV4)
609                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
610                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
611                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
612                         else
613                                 BUG();
614                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
615                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
616                 } else
617                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
618
619                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
620                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
621                         gso.csum_start = skb->csum_start - skb_headroom(skb);
622                         gso.csum_offset = skb->csum_offset;
623                 } /* else everything is zero */
624
625                 if (unlikely(memcpy_toiovec(iv, (void *)&gso, sizeof(gso))))
626                         return -EFAULT;
627                 total += sizeof(gso);
628         }
629
630         len = min_t(int, skb->len, len);
631
632         skb_copy_datagram_iovec(skb, 0, iv, len);
633         total += len;
634
635         tun->dev->stats.tx_packets++;
636         tun->dev->stats.tx_bytes += len;
637
638         return total;
639 }
640
641 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
642                             unsigned long count, loff_t pos)
643 {
644         struct file *file = iocb->ki_filp;
645         struct tun_struct *tun = file->private_data;
646         DECLARE_WAITQUEUE(wait, current);
647         struct sk_buff *skb;
648         ssize_t len, ret = 0;
649
650         if (!tun)
651                 return -EBADFD;
652
653         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
654
655         len = iov_length(iv, count);
656         if (len < 0)
657                 return -EINVAL;
658
659         add_wait_queue(&tun->read_wait, &wait);
660         while (len) {
661                 current->state = TASK_INTERRUPTIBLE;
662
663                 /* Read frames from the queue */
664                 if (!(skb=skb_dequeue(&tun->readq))) {
665                         if (file->f_flags & O_NONBLOCK) {
666                                 ret = -EAGAIN;
667                                 break;
668                         }
669                         if (signal_pending(current)) {
670                                 ret = -ERESTARTSYS;
671                                 break;
672                         }
673
674                         /* Nothing to read, let's sleep */
675                         schedule();
676                         continue;
677                 }
678                 netif_wake_queue(tun->dev);
679
680                 ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
681                 kfree_skb(skb);
682                 break;
683         }
684
685         current->state = TASK_RUNNING;
686         remove_wait_queue(&tun->read_wait, &wait);
687
688         return ret;
689 }
690
691 static void tun_setup(struct net_device *dev)
692 {
693         struct tun_struct *tun = netdev_priv(dev);
694
695         skb_queue_head_init(&tun->readq);
696         init_waitqueue_head(&tun->read_wait);
697
698         tun->owner = -1;
699         tun->group = -1;
700
701         dev->ethtool_ops = &tun_ethtool_ops;
702         dev->destructor = free_netdev;
703         dev->features |= NETIF_F_NETNS_LOCAL;
704 }
705
706 static struct tun_struct *tun_get_by_name(struct tun_net *tn, const char *name)
707 {
708         struct tun_struct *tun;
709
710         ASSERT_RTNL();
711         list_for_each_entry(tun, &tn->dev_list, list) {
712                 if (!strncmp(tun->dev->name, name, IFNAMSIZ))
713                     return tun;
714         }
715
716         return NULL;
717 }
718
719 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
720 {
721         struct tun_net *tn;
722         struct tun_struct *tun;
723         struct net_device *dev;
724         const struct cred *cred = current_cred();
725         int err;
726
727         tn = net_generic(net, tun_net_id);
728         tun = tun_get_by_name(tn, ifr->ifr_name);
729         if (tun) {
730                 if (tun->attached)
731                         return -EBUSY;
732
733                 /* Check permissions */
734                 if (((tun->owner != -1 &&
735                       cred->euid != tun->owner) ||
736                      (tun->group != -1 &&
737                       cred->egid != tun->group)) &&
738                     !capable(CAP_NET_ADMIN)) {
739                         return -EPERM;
740                 }
741         }
742         else if (__dev_get_by_name(net, ifr->ifr_name))
743                 return -EINVAL;
744         else {
745                 char *name;
746                 unsigned long flags = 0;
747
748                 err = -EINVAL;
749
750                 if (!capable(CAP_NET_ADMIN))
751                         return -EPERM;
752
753                 /* Set dev type */
754                 if (ifr->ifr_flags & IFF_TUN) {
755                         /* TUN device */
756                         flags |= TUN_TUN_DEV;
757                         name = "tun%d";
758                 } else if (ifr->ifr_flags & IFF_TAP) {
759                         /* TAP device */
760                         flags |= TUN_TAP_DEV;
761                         name = "tap%d";
762                 } else
763                         goto failed;
764
765                 if (*ifr->ifr_name)
766                         name = ifr->ifr_name;
767
768                 dev = alloc_netdev(sizeof(struct tun_struct), name,
769                                    tun_setup);
770                 if (!dev)
771                         return -ENOMEM;
772
773                 dev_net_set(dev, net);
774
775                 tun = netdev_priv(dev);
776                 tun->dev = dev;
777                 tun->flags = flags;
778                 tun->txflt.count = 0;
779
780                 tun_net_init(dev);
781
782                 if (strchr(dev->name, '%')) {
783                         err = dev_alloc_name(dev, dev->name);
784                         if (err < 0)
785                                 goto err_free_dev;
786                 }
787
788                 err = register_netdevice(tun->dev);
789                 if (err < 0)
790                         goto err_free_dev;
791
792                 list_add(&tun->list, &tn->dev_list);
793         }
794
795         DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
796
797         if (ifr->ifr_flags & IFF_NO_PI)
798                 tun->flags |= TUN_NO_PI;
799         else
800                 tun->flags &= ~TUN_NO_PI;
801
802         if (ifr->ifr_flags & IFF_ONE_QUEUE)
803                 tun->flags |= TUN_ONE_QUEUE;
804         else
805                 tun->flags &= ~TUN_ONE_QUEUE;
806
807         if (ifr->ifr_flags & IFF_VNET_HDR)
808                 tun->flags |= TUN_VNET_HDR;
809         else
810                 tun->flags &= ~TUN_VNET_HDR;
811
812         file->private_data = tun;
813         tun->attached = 1;
814         get_net(dev_net(tun->dev));
815
816         /* Make sure persistent devices do not get stuck in
817          * xoff state.
818          */
819         if (netif_running(tun->dev))
820                 netif_wake_queue(tun->dev);
821
822         strcpy(ifr->ifr_name, tun->dev->name);
823         return 0;
824
825  err_free_dev:
826         free_netdev(dev);
827  failed:
828         return err;
829 }
830
831 static int tun_get_iff(struct net *net, struct file *file, struct ifreq *ifr)
832 {
833         struct tun_struct *tun = file->private_data;
834
835         if (!tun)
836                 return -EBADFD;
837
838         DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
839
840         strcpy(ifr->ifr_name, tun->dev->name);
841
842         ifr->ifr_flags = 0;
843
844         if (ifr->ifr_flags & TUN_TUN_DEV)
845                 ifr->ifr_flags |= IFF_TUN;
846         else
847                 ifr->ifr_flags |= IFF_TAP;
848
849         if (tun->flags & TUN_NO_PI)
850                 ifr->ifr_flags |= IFF_NO_PI;
851
852         if (tun->flags & TUN_ONE_QUEUE)
853                 ifr->ifr_flags |= IFF_ONE_QUEUE;
854
855         if (tun->flags & TUN_VNET_HDR)
856                 ifr->ifr_flags |= IFF_VNET_HDR;
857
858         return 0;
859 }
860
861 /* This is like a cut-down ethtool ops, except done via tun fd so no
862  * privs required. */
863 static int set_offload(struct net_device *dev, unsigned long arg)
864 {
865         unsigned int old_features, features;
866
867         old_features = dev->features;
868         /* Unset features, set them as we chew on the arg. */
869         features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
870                                     |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6));
871
872         if (arg & TUN_F_CSUM) {
873                 features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
874                 arg &= ~TUN_F_CSUM;
875
876                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
877                         if (arg & TUN_F_TSO_ECN) {
878                                 features |= NETIF_F_TSO_ECN;
879                                 arg &= ~TUN_F_TSO_ECN;
880                         }
881                         if (arg & TUN_F_TSO4)
882                                 features |= NETIF_F_TSO;
883                         if (arg & TUN_F_TSO6)
884                                 features |= NETIF_F_TSO6;
885                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
886                 }
887         }
888
889         /* This gives the user a way to test for new features in future by
890          * trying to set them. */
891         if (arg)
892                 return -EINVAL;
893
894         dev->features = features;
895         if (old_features != dev->features)
896                 netdev_features_change(dev);
897
898         return 0;
899 }
900
901 static int tun_chr_ioctl(struct inode *inode, struct file *file,
902                          unsigned int cmd, unsigned long arg)
903 {
904         struct tun_struct *tun = file->private_data;
905         void __user* argp = (void __user*)arg;
906         struct ifreq ifr;
907         int ret;
908
909         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
910                 if (copy_from_user(&ifr, argp, sizeof ifr))
911                         return -EFAULT;
912
913         if (cmd == TUNSETIFF && !tun) {
914                 int err;
915
916                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
917
918                 rtnl_lock();
919                 err = tun_set_iff(current->nsproxy->net_ns, file, &ifr);
920                 rtnl_unlock();
921
922                 if (err)
923                         return err;
924
925                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
926                         return -EFAULT;
927                 return 0;
928         }
929
930         if (cmd == TUNGETFEATURES) {
931                 /* Currently this just means: "what IFF flags are valid?".
932                  * This is needed because we never checked for invalid flags on
933                  * TUNSETIFF. */
934                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
935                                 IFF_VNET_HDR,
936                                 (unsigned int __user*)argp);
937         }
938
939         if (!tun)
940                 return -EBADFD;
941
942         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
943
944         switch (cmd) {
945         case TUNGETIFF:
946                 ret = tun_get_iff(current->nsproxy->net_ns, file, &ifr);
947                 if (ret)
948                         return ret;
949
950                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
951                         return -EFAULT;
952                 break;
953
954         case TUNSETNOCSUM:
955                 /* Disable/Enable checksum */
956                 if (arg)
957                         tun->flags |= TUN_NOCHECKSUM;
958                 else
959                         tun->flags &= ~TUN_NOCHECKSUM;
960
961                 DBG(KERN_INFO "%s: checksum %s\n",
962                     tun->dev->name, arg ? "disabled" : "enabled");
963                 break;
964
965         case TUNSETPERSIST:
966                 /* Disable/Enable persist mode */
967                 if (arg)
968                         tun->flags |= TUN_PERSIST;
969                 else
970                         tun->flags &= ~TUN_PERSIST;
971
972                 DBG(KERN_INFO "%s: persist %s\n",
973                     tun->dev->name, arg ? "enabled" : "disabled");
974                 break;
975
976         case TUNSETOWNER:
977                 /* Set owner of the device */
978                 tun->owner = (uid_t) arg;
979
980                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
981                 break;
982
983         case TUNSETGROUP:
984                 /* Set group of the device */
985                 tun->group= (gid_t) arg;
986
987                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
988                 break;
989
990         case TUNSETLINK:
991                 /* Only allow setting the type when the interface is down */
992                 rtnl_lock();
993                 if (tun->dev->flags & IFF_UP) {
994                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
995                                 tun->dev->name);
996                         ret = -EBUSY;
997                 } else {
998                         tun->dev->type = (int) arg;
999                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
1000                         ret = 0;
1001                 }
1002                 rtnl_unlock();
1003                 return ret;
1004
1005 #ifdef TUN_DEBUG
1006         case TUNSETDEBUG:
1007                 tun->debug = arg;
1008                 break;
1009 #endif
1010         case TUNSETOFFLOAD:
1011                 rtnl_lock();
1012                 ret = set_offload(tun->dev, arg);
1013                 rtnl_unlock();
1014                 return ret;
1015
1016         case TUNSETTXFILTER:
1017                 /* Can be set only for TAPs */
1018                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1019                         return -EINVAL;
1020                 rtnl_lock();
1021                 ret = update_filter(&tun->txflt, (void __user *)arg);
1022                 rtnl_unlock();
1023                 return ret;
1024
1025         case SIOCGIFHWADDR:
1026                 /* Get hw addres */
1027                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1028                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1029                 if (copy_to_user(argp, &ifr, sizeof ifr))
1030                         return -EFAULT;
1031                 return 0;
1032
1033         case SIOCSIFHWADDR:
1034                 /* Set hw address */
1035                 DBG(KERN_DEBUG "%s: set hw address: %pM\n",
1036                         tun->dev->name, ifr.ifr_hwaddr.sa_data);
1037
1038                 rtnl_lock();
1039                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1040                 rtnl_unlock();
1041                 return ret;
1042
1043         default:
1044                 return -EINVAL;
1045         };
1046
1047         return 0;
1048 }
1049
1050 static int tun_chr_fasync(int fd, struct file *file, int on)
1051 {
1052         struct tun_struct *tun = file->private_data;
1053         int ret;
1054
1055         if (!tun)
1056                 return -EBADFD;
1057
1058         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
1059
1060         lock_kernel();
1061         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1062                 goto out;
1063
1064         if (on) {
1065                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1066                 if (ret)
1067                         goto out;
1068                 tun->flags |= TUN_FASYNC;
1069         } else
1070                 tun->flags &= ~TUN_FASYNC;
1071         ret = 0;
1072 out:
1073         unlock_kernel();
1074         return ret;
1075 }
1076
1077 static int tun_chr_open(struct inode *inode, struct file * file)
1078 {
1079         cycle_kernel_lock();
1080         DBG1(KERN_INFO "tunX: tun_chr_open\n");
1081         file->private_data = NULL;
1082         return 0;
1083 }
1084
1085 static int tun_chr_close(struct inode *inode, struct file *file)
1086 {
1087         struct tun_struct *tun = file->private_data;
1088
1089         if (!tun)
1090                 return 0;
1091
1092         DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
1093
1094         rtnl_lock();
1095
1096         /* Detach from net device */
1097         file->private_data = NULL;
1098         tun->attached = 0;
1099         put_net(dev_net(tun->dev));
1100
1101         /* Drop read queue */
1102         skb_queue_purge(&tun->readq);
1103
1104         if (!(tun->flags & TUN_PERSIST)) {
1105                 list_del(&tun->list);
1106                 unregister_netdevice(tun->dev);
1107         }
1108
1109         rtnl_unlock();
1110
1111         return 0;
1112 }
1113
1114 static const struct file_operations tun_fops = {
1115         .owner  = THIS_MODULE,
1116         .llseek = no_llseek,
1117         .read  = do_sync_read,
1118         .aio_read  = tun_chr_aio_read,
1119         .write = do_sync_write,
1120         .aio_write = tun_chr_aio_write,
1121         .poll   = tun_chr_poll,
1122         .ioctl  = tun_chr_ioctl,
1123         .open   = tun_chr_open,
1124         .release = tun_chr_close,
1125         .fasync = tun_chr_fasync
1126 };
1127
1128 static struct miscdevice tun_miscdev = {
1129         .minor = TUN_MINOR,
1130         .name = "tun",
1131         .fops = &tun_fops,
1132 };
1133
1134 /* ethtool interface */
1135
1136 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1137 {
1138         cmd->supported          = 0;
1139         cmd->advertising        = 0;
1140         cmd->speed              = SPEED_10;
1141         cmd->duplex             = DUPLEX_FULL;
1142         cmd->port               = PORT_TP;
1143         cmd->phy_address        = 0;
1144         cmd->transceiver        = XCVR_INTERNAL;
1145         cmd->autoneg            = AUTONEG_DISABLE;
1146         cmd->maxtxpkt           = 0;
1147         cmd->maxrxpkt           = 0;
1148         return 0;
1149 }
1150
1151 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1152 {
1153         struct tun_struct *tun = netdev_priv(dev);
1154
1155         strcpy(info->driver, DRV_NAME);
1156         strcpy(info->version, DRV_VERSION);
1157         strcpy(info->fw_version, "N/A");
1158
1159         switch (tun->flags & TUN_TYPE_MASK) {
1160         case TUN_TUN_DEV:
1161                 strcpy(info->bus_info, "tun");
1162                 break;
1163         case TUN_TAP_DEV:
1164                 strcpy(info->bus_info, "tap");
1165                 break;
1166         }
1167 }
1168
1169 static u32 tun_get_msglevel(struct net_device *dev)
1170 {
1171 #ifdef TUN_DEBUG
1172         struct tun_struct *tun = netdev_priv(dev);
1173         return tun->debug;
1174 #else
1175         return -EOPNOTSUPP;
1176 #endif
1177 }
1178
1179 static void tun_set_msglevel(struct net_device *dev, u32 value)
1180 {
1181 #ifdef TUN_DEBUG
1182         struct tun_struct *tun = netdev_priv(dev);
1183         tun->debug = value;
1184 #endif
1185 }
1186
1187 static u32 tun_get_link(struct net_device *dev)
1188 {
1189         struct tun_struct *tun = netdev_priv(dev);
1190         return tun->attached;
1191 }
1192
1193 static u32 tun_get_rx_csum(struct net_device *dev)
1194 {
1195         struct tun_struct *tun = netdev_priv(dev);
1196         return (tun->flags & TUN_NOCHECKSUM) == 0;
1197 }
1198
1199 static int tun_set_rx_csum(struct net_device *dev, u32 data)
1200 {
1201         struct tun_struct *tun = netdev_priv(dev);
1202         if (data)
1203                 tun->flags &= ~TUN_NOCHECKSUM;
1204         else
1205                 tun->flags |= TUN_NOCHECKSUM;
1206         return 0;
1207 }
1208
1209 static const struct ethtool_ops tun_ethtool_ops = {
1210         .get_settings   = tun_get_settings,
1211         .get_drvinfo    = tun_get_drvinfo,
1212         .get_msglevel   = tun_get_msglevel,
1213         .set_msglevel   = tun_set_msglevel,
1214         .get_link       = tun_get_link,
1215         .get_rx_csum    = tun_get_rx_csum,
1216         .set_rx_csum    = tun_set_rx_csum
1217 };
1218
1219 static int tun_init_net(struct net *net)
1220 {
1221         struct tun_net *tn;
1222
1223         tn = kmalloc(sizeof(*tn), GFP_KERNEL);
1224         if (tn == NULL)
1225                 return -ENOMEM;
1226
1227         INIT_LIST_HEAD(&tn->dev_list);
1228
1229         if (net_assign_generic(net, tun_net_id, tn)) {
1230                 kfree(tn);
1231                 return -ENOMEM;
1232         }
1233
1234         return 0;
1235 }
1236
1237 static void tun_exit_net(struct net *net)
1238 {
1239         struct tun_net *tn;
1240         struct tun_struct *tun, *nxt;
1241
1242         tn = net_generic(net, tun_net_id);
1243
1244         rtnl_lock();
1245         list_for_each_entry_safe(tun, nxt, &tn->dev_list, list) {
1246                 DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
1247                 unregister_netdevice(tun->dev);
1248         }
1249         rtnl_unlock();
1250
1251         kfree(tn);
1252 }
1253
1254 static struct pernet_operations tun_net_ops = {
1255         .init = tun_init_net,
1256         .exit = tun_exit_net,
1257 };
1258
1259 static int __init tun_init(void)
1260 {
1261         int ret = 0;
1262
1263         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1264         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
1265
1266         ret = register_pernet_gen_device(&tun_net_id, &tun_net_ops);
1267         if (ret) {
1268                 printk(KERN_ERR "tun: Can't register pernet ops\n");
1269                 goto err_pernet;
1270         }
1271
1272         ret = misc_register(&tun_miscdev);
1273         if (ret) {
1274                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
1275                 goto err_misc;
1276         }
1277         return 0;
1278
1279 err_misc:
1280         unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
1281 err_pernet:
1282         return ret;
1283 }
1284
1285 static void tun_cleanup(void)
1286 {
1287         misc_deregister(&tun_miscdev);
1288         unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
1289 }
1290
1291 module_init(tun_init);
1292 module_exit(tun_cleanup);
1293 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1294 MODULE_AUTHOR(DRV_COPYRIGHT);
1295 MODULE_LICENSE("GPL");
1296 MODULE_ALIAS_MISCDEV(TUN_MINOR);