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