drivers/net/tun.c

   1 /*
   2  *  TUN - Universal TUN/TAP device driver.
   3  *  Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
  16  */
  17
  18 /*
  19  *  Changes:
  20  *
  21  *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
  22  *    Add TUNSETLINK ioctl to set the link encapsulation
  23  *
  24  *  Mark Smith <markzzzsmith@yahoo.com.au>
  25  *    Use eth_random_addr() for tap MAC address.
  26  *
  27  *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
  28  *    Fixes in packet dropping, queue length setting and queue wakeup.
  29  *    Increased default tx queue length.
  30  *    Added ethtool API.
  31  *    Minor cleanups
  32  *
  33  *  Daniel Podlejski <underley@underley.eu.org>
  34  *    Modifications for 2.3.99-pre5 kernel.
  35  */
  36
  37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  38
  39 #define DRV_NAME        "tun"
  40 #define DRV_VERSION     "1.6"
  41 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  42 #define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
  43
  44 #include <linux/module.h>
  45 #include <linux/errno.h>
  46 #include <linux/kernel.h>
  47 #include <linux/major.h>
  48 #include <linux/slab.h>
  49 #include <linux/poll.h>
  50 #include <linux/fcntl.h>
  51 #include <linux/init.h>
  52 #include <linux/skbuff.h>
  53 #include <linux/netdevice.h>
  54 #include <linux/etherdevice.h>
  55 #include <linux/miscdevice.h>
  56 #include <linux/ethtool.h>
  57 #include <linux/rtnetlink.h>
  58 #include <linux/compat.h>
  59 #include <linux/if.h>
  60 #include <linux/if_arp.h>
  61 #include <linux/if_ether.h>
  62 #include <linux/if_tun.h>
  63 #include <linux/if_vlan.h>
  64 #include <linux/crc32.h>
  65 #include <linux/nsproxy.h>
  66 #include <linux/virtio_net.h>
  67 #include <linux/rcupdate.h>
  68 #include <net/ipv6.h>
  69 #include <net/net_namespace.h>
  70 #include <net/netns/generic.h>
  71 #include <net/rtnetlink.h>
  72 #include <net/sock.h>
  73 #include <linux/seq_file.h>
  74
  75 #include <asm/uaccess.h>
  76
  77 /* Uncomment to enable debugging */
  78 /* #define TUN_DEBUG 1 */
  79
  80 #ifdef TUN_DEBUG
  81 static int debug;
  82
  83 #define tun_debug(level, tun, fmt, args...)                     \
  84 do {                                                            \
  85         if (tun->debug)                                         \
  86                 netdev_printk(level, tun->dev, fmt, ##args);    \
  87 } while (0)
  88 #define DBG1(level, fmt, args...)                               \
  89 do {                                                            \
  90         if (debug == 2)                                         \
  91                 printk(level fmt, ##args);                      \
  92 } while (0)
  93 #else
  94 #define tun_debug(level, tun, fmt, args...)                     \
  95 do {                                                            \
  96         if (0)                                                  \
  97                 netdev_printk(level, tun->dev, fmt, ##args);    \
  98 } while (0)
  99 #define DBG1(level, fmt, args...)                               \
 100 do {                                                            \
 101         if (0)                                                  \
 102                 printk(level fmt, ##args);                      \
 103 } while (0)
 104 #endif
 105
 106 #define GOODCOPY_LEN 128
 107
 108 #define FLT_EXACT_COUNT 8
 109 struct tap_filter {
 110         unsigned int    count;    /* Number of addrs. Zero means disabled */
 111         u32             mask[2];  /* Mask of the hashed addrs */
 112         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 113 };
 114
 115 /* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for
 116  * the netdevice to be fit in one page. So we can make sure the success of
 117  * memory allocation. TODO: increase the limit. */
 118 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES
 119 #define MAX_TAP_FLOWS  4096
 120
 121 #define TUN_FLOW_EXPIRE (3 * HZ)
 122
 123 /* A tun_file connects an open character device to a tuntap netdevice. It
 124  * also contains all socket related structures (except sock_fprog and tap_filter)
 125  * to serve as one transmit queue for tuntap device. The sock_fprog and
 126  * tap_filter were kept in tun_struct since they were used for filtering for the
 127  * netdevice not for a specific queue (at least I didn't see the requirement for
 128  * this).
 129  *
 130  * RCU usage:
 131  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
 132  * other can only be read while rcu_read_lock or rtnl_lock is held.
 133  */
 134 struct tun_file {
 135         struct sock sk;
 136         struct socket socket;
 137         struct socket_wq wq;
 138         struct tun_struct __rcu *tun;
 139         struct net *net;
 140         struct fasync_struct *fasync;
 141         /* only used for fasnyc */
 142         unsigned int flags;
 143         union {
 144                 u16 queue_index;
 145                 unsigned int ifindex;
 146         };
 147         struct list_head next;
 148         struct tun_struct *detached;
 149 };
 150
 151 struct tun_flow_entry {
 152         struct hlist_node hash_link;
 153         struct rcu_head rcu;
 154         struct tun_struct *tun;
 155
 156         u32 rxhash;
 157         u32 rps_rxhash;
 158         int queue_index;
 159         unsigned long updated;
 160 };
 161
 162 #define TUN_NUM_FLOW_ENTRIES 1024
 163
 164 /* Since the socket were moved to tun_file, to preserve the behavior of persist
 165  * device, socket filter, sndbuf and vnet header size were restore when the
 166  * file were attached to a persist device.
 167  */
 168 struct tun_struct {
 169         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
 170         unsigned int            numqueues;
 171         unsigned int            flags;
 172         kuid_t                  owner;
 173         kgid_t                  group;
 174
 175         struct net_device       *dev;
 176         netdev_features_t       set_features;
 177 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 178                           NETIF_F_TSO6|NETIF_F_UFO)
 179
 180         int                     vnet_hdr_sz;
 181         int                     sndbuf;
 182         struct tap_filter       txflt;
 183         struct sock_fprog       fprog;
 184         /* protected by rtnl lock */
 185         bool                    filter_attached;
 186 #ifdef TUN_DEBUG
 187         int debug;
 188 #endif
 189         spinlock_t lock;
 190         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 191         struct timer_list flow_gc_timer;
 192         unsigned long ageing_time;
 193         unsigned int numdisabled;
 194         struct list_head disabled;
 195         void *security;
 196         u32 flow_count;
 197 };
 198
 199 static inline u32 tun_hashfn(u32 rxhash)
 200 {
 201         return rxhash & 0x3ff;
 202 }
 203
 204 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 205 {
 206         struct tun_flow_entry *e;
 207
 208         hlist_for_each_entry_rcu(e, head, hash_link) {
 209                 if (e->rxhash == rxhash)
 210                         return e;
 211         }
 212         return NULL;
 213 }
 214
 215 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 216                                               struct hlist_head *head,
 217                                               u32 rxhash, u16 queue_index)
 218 {
 219         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 220
 221         if (e) {
 222                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 223                           rxhash, queue_index);
 224                 e->updated = jiffies;
 225                 e->rxhash = rxhash;
 226                 e->rps_rxhash = 0;
 227                 e->queue_index = queue_index;
 228                 e->tun = tun;
 229                 hlist_add_head_rcu(&e->hash_link, head);
 230                 ++tun->flow_count;
 231         }
 232         return e;
 233 }
 234
 235 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 236 {
 237         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 238                   e->rxhash, e->queue_index);
 239         sock_rps_reset_flow_hash(e->rps_rxhash);
 240         hlist_del_rcu(&e->hash_link);
 241         kfree_rcu(e, rcu);
 242         --tun->flow_count;
 243 }
 244
 245 static void tun_flow_flush(struct tun_struct *tun)
 246 {
 247         int i;
 248
 249         spin_lock_bh(&tun->lock);
 250         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 251                 struct tun_flow_entry *e;
 252                 struct hlist_node *n;
 253
 254                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 255                         tun_flow_delete(tun, e);
 256         }
 257         spin_unlock_bh(&tun->lock);
 258 }
 259
 260 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 261 {
 262         int i;
 263
 264         spin_lock_bh(&tun->lock);
 265         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 266                 struct tun_flow_entry *e;
 267                 struct hlist_node *n;
 268
 269                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 270                         if (e->queue_index == queue_index)
 271                                 tun_flow_delete(tun, e);
 272                 }
 273         }
 274         spin_unlock_bh(&tun->lock);
 275 }
 276
 277 static void tun_flow_cleanup(unsigned long data)
 278 {
 279         struct tun_struct *tun = (struct tun_struct *)data;
 280         unsigned long delay = tun->ageing_time;
 281         unsigned long next_timer = jiffies + delay;
 282         unsigned long count = 0;
 283         int i;
 284
 285         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 286
 287         spin_lock_bh(&tun->lock);
 288         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 289                 struct tun_flow_entry *e;
 290                 struct hlist_node *n;
 291
 292                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 293                         unsigned long this_timer;
 294                         count++;
 295                         this_timer = e->updated + delay;
 296                         if (time_before_eq(this_timer, jiffies))
 297                                 tun_flow_delete(tun, e);
 298                         else if (time_before(this_timer, next_timer))
 299                                 next_timer = this_timer;
 300                 }
 301         }
 302
 303         if (count)
 304                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 305         spin_unlock_bh(&tun->lock);
 306 }
 307
 308 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 309                             struct tun_file *tfile)
 310 {
 311         struct hlist_head *head;
 312         struct tun_flow_entry *e;
 313         unsigned long delay = tun->ageing_time;
 314         u16 queue_index = tfile->queue_index;
 315
 316         if (!rxhash)
 317                 return;
 318         else
 319                 head = &tun->flows[tun_hashfn(rxhash)];
 320
 321         rcu_read_lock();
 322
 323         /* We may get a very small possibility of OOO during switching, not
 324          * worth to optimize.*/
 325         if (tun->numqueues == 1 || tfile->detached)
 326                 goto unlock;
 327
 328         e = tun_flow_find(head, rxhash);
 329         if (likely(e)) {
 330                 /* TODO: keep queueing to old queue until it's empty? */
 331                 e->queue_index = queue_index;
 332                 e->updated = jiffies;
 333                 sock_rps_record_flow_hash(e->rps_rxhash);
 334         } else {
 335                 spin_lock_bh(&tun->lock);
 336                 if (!tun_flow_find(head, rxhash) &&
 337                     tun->flow_count < MAX_TAP_FLOWS)
 338                         tun_flow_create(tun, head, rxhash, queue_index);
 339
 340                 if (!timer_pending(&tun->flow_gc_timer))
 341                         mod_timer(&tun->flow_gc_timer,
 342                                   round_jiffies_up(jiffies + delay));
 343                 spin_unlock_bh(&tun->lock);
 344         }
 345
 346 unlock:
 347         rcu_read_unlock();
 348 }
 349
 350 /**
 351  * Save the hash received in the stack receive path and update the
 352  * flow_hash table accordingly.
 353  */
 354 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
 355 {
 356         if (unlikely(e->rps_rxhash != hash)) {
 357                 sock_rps_reset_flow_hash(e->rps_rxhash);
 358                 e->rps_rxhash = hash;
 359         }
 360 }
 361
 362 /* We try to identify a flow through its rxhash first. The reason that
 363  * we do not check rxq no. is because some cards(e.g 82599), chooses
 364  * the rxq based on the txq where the last packet of the flow comes. As
 365  * the userspace application move between processors, we may get a
 366  * different rxq no. here. If we could not get rxhash, then we would
 367  * hope the rxq no. may help here.
 368  */
 369 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
 370                             void *accel_priv, select_queue_fallback_t fallback)
 371 {
 372         struct tun_struct *tun = netdev_priv(dev);
 373         struct tun_flow_entry *e;
 374         u32 txq = 0;
 375         u32 numqueues = 0;
 376
 377         rcu_read_lock();
 378         numqueues = ACCESS_ONCE(tun->numqueues);
 379
 380         txq = skb_get_hash(skb);
 381         if (txq) {
 382                 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 383                 if (e) {
 384                         tun_flow_save_rps_rxhash(e, txq);
 385                         txq = e->queue_index;
 386                 } else
 387                         /* use multiply and shift instead of expensive divide */
 388                         txq = ((u64)txq * numqueues) >> 32;
 389         } else if (likely(skb_rx_queue_recorded(skb))) {
 390                 txq = skb_get_rx_queue(skb);
 391                 while (unlikely(txq >= numqueues))
 392                         txq -= numqueues;
 393         }
 394
 395         rcu_read_unlock();
 396         return txq;
 397 }
 398
 399 static inline bool tun_not_capable(struct tun_struct *tun)
 400 {
 401         const struct cred *cred = current_cred();
 402         struct net *net = dev_net(tun->dev);
 403
 404         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 405                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 406                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 407 }
 408
 409 static void tun_set_real_num_queues(struct tun_struct *tun)
 410 {
 411         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 412         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 413 }
 414
 415 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 416 {
 417         tfile->detached = tun;
 418         list_add_tail(&tfile->next, &tun->disabled);
 419         ++tun->numdisabled;
 420 }
 421
 422 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 423 {
 424         struct tun_struct *tun = tfile->detached;
 425
 426         tfile->detached = NULL;
 427         list_del_init(&tfile->next);
 428         --tun->numdisabled;
 429         return tun;
 430 }
 431
 432 static void tun_queue_purge(struct tun_file *tfile)
 433 {
 434         skb_queue_purge(&tfile->sk.sk_receive_queue);
 435         skb_queue_purge(&tfile->sk.sk_error_queue);
 436 }
 437
 438 static void __tun_detach(struct tun_file *tfile, bool clean)
 439 {
 440         struct tun_file *ntfile;
 441         struct tun_struct *tun;
 442
 443         tun = rtnl_dereference(tfile->tun);
 444
 445         if (tun && !tfile->detached) {
 446                 u16 index = tfile->queue_index;
 447                 BUG_ON(index >= tun->numqueues);
 448
 449                 rcu_assign_pointer(tun->tfiles[index],
 450                                    tun->tfiles[tun->numqueues - 1]);
 451                 ntfile = rtnl_dereference(tun->tfiles[index]);
 452                 ntfile->queue_index = index;
 453
 454                 --tun->numqueues;
 455                 if (clean) {
 456                         rcu_assign_pointer(tfile->tun, NULL);
 457                         sock_put(&tfile->sk);
 458                 } else
 459                         tun_disable_queue(tun, tfile);
 460
 461                 synchronize_net();
 462                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 463                 /* Drop read queue */
 464                 tun_queue_purge(tfile);
 465                 tun_set_real_num_queues(tun);
 466         } else if (tfile->detached && clean) {
 467                 tun = tun_enable_queue(tfile);
 468                 sock_put(&tfile->sk);
 469         }
 470
 471         if (clean) {
 472                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 473                         netif_carrier_off(tun->dev);
 474
 475                         if (!(tun->flags & TUN_PERSIST) &&
 476                             tun->dev->reg_state == NETREG_REGISTERED)
 477                                 unregister_netdevice(tun->dev);
 478                 }
 479
 480                 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
 481                                  &tfile->socket.flags));
 482                 sk_release_kernel(&tfile->sk);
 483         }
 484 }
 485
 486 static void tun_detach(struct tun_file *tfile, bool clean)
 487 {
 488         rtnl_lock();
 489         __tun_detach(tfile, clean);
 490         rtnl_unlock();
 491 }
 492
 493 static void tun_detach_all(struct net_device *dev)
 494 {
 495         struct tun_struct *tun = netdev_priv(dev);
 496         struct tun_file *tfile, *tmp;
 497         int i, n = tun->numqueues;
 498
 499         for (i = 0; i < n; i++) {
 500                 tfile = rtnl_dereference(tun->tfiles[i]);
 501                 BUG_ON(!tfile);
 502                 wake_up_all(&tfile->wq.wait);
 503                 rcu_assign_pointer(tfile->tun, NULL);
 504                 --tun->numqueues;
 505         }
 506         list_for_each_entry(tfile, &tun->disabled, next) {
 507                 wake_up_all(&tfile->wq.wait);
 508                 rcu_assign_pointer(tfile->tun, NULL);
 509         }
 510         BUG_ON(tun->numqueues != 0);
 511
 512         synchronize_net();
 513         for (i = 0; i < n; i++) {
 514                 tfile = rtnl_dereference(tun->tfiles[i]);
 515                 /* Drop read queue */
 516                 tun_queue_purge(tfile);
 517                 sock_put(&tfile->sk);
 518         }
 519         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 520                 tun_enable_queue(tfile);
 521                 tun_queue_purge(tfile);
 522                 sock_put(&tfile->sk);
 523         }
 524         BUG_ON(tun->numdisabled != 0);
 525
 526         if (tun->flags & TUN_PERSIST)
 527                 module_put(THIS_MODULE);
 528 }
 529
 530 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
 531 {
 532         struct tun_file *tfile = file->private_data;
 533         int err;
 534
 535         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 536         if (err < 0)
 537                 goto out;
 538
 539         err = -EINVAL;
 540         if (rtnl_dereference(tfile->tun) && !tfile->detached)
 541                 goto out;
 542
 543         err = -EBUSY;
 544         if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1)
 545                 goto out;
 546
 547         err = -E2BIG;
 548         if (!tfile->detached &&
 549             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 550                 goto out;
 551
 552         err = 0;
 553
 554         /* Re-attach the filter to persist device */
 555         if (!skip_filter && (tun->filter_attached == true)) {
 556                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 557                 if (!err)
 558                         goto out;
 559         }
 560         tfile->queue_index = tun->numqueues;
 561         rcu_assign_pointer(tfile->tun, tun);
 562         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 563         tun->numqueues++;
 564
 565         if (tfile->detached)
 566                 tun_enable_queue(tfile);
 567         else
 568                 sock_hold(&tfile->sk);
 569
 570         tun_set_real_num_queues(tun);
 571
 572         /* device is allowed to go away first, so no need to hold extra
 573          * refcnt.
 574          */
 575
 576 out:
 577         return err;
 578 }
 579
 580 static struct tun_struct *__tun_get(struct tun_file *tfile)
 581 {
 582         struct tun_struct *tun;
 583
 584         rcu_read_lock();
 585         tun = rcu_dereference(tfile->tun);
 586         if (tun)
 587                 dev_hold(tun->dev);
 588         rcu_read_unlock();
 589
 590         return tun;
 591 }
 592
 593 static struct tun_struct *tun_get(struct file *file)
 594 {
 595         return __tun_get(file->private_data);
 596 }
 597
 598 static void tun_put(struct tun_struct *tun)
 599 {
 600         dev_put(tun->dev);
 601 }
 602
 603 /* TAP filtering */
 604 static void addr_hash_set(u32 *mask, const u8 *addr)
 605 {
 606         int n = ether_crc(ETH_ALEN, addr) >> 26;
 607         mask[n >> 5] |= (1 << (n & 31));
 608 }
 609
 610 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 611 {
 612         int n = ether_crc(ETH_ALEN, addr) >> 26;
 613         return mask[n >> 5] & (1 << (n & 31));
 614 }
 615
 616 static int update_filter(struct tap_filter *filter, void __user *arg)
 617 {
 618         struct { u8 u[ETH_ALEN]; } *addr;
 619         struct tun_filter uf;
 620         int err, alen, n, nexact;
 621
 622         if (copy_from_user(&uf, arg, sizeof(uf)))
 623                 return -EFAULT;
 624
 625         if (!uf.count) {
 626                 /* Disabled */
 627                 filter->count = 0;
 628                 return 0;
 629         }
 630
 631         alen = ETH_ALEN * uf.count;
 632         addr = kmalloc(alen, GFP_KERNEL);
 633         if (!addr)
 634                 return -ENOMEM;
 635
 636         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 637                 err = -EFAULT;
 638                 goto done;
 639         }
 640
 641         /* The filter is updated without holding any locks. Which is
 642          * perfectly safe. We disable it first and in the worst
 643          * case we'll accept a few undesired packets. */
 644         filter->count = 0;
 645         wmb();
 646
 647         /* Use first set of addresses as an exact filter */
 648         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 649                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 650
 651         nexact = n;
 652
 653         /* Remaining multicast addresses are hashed,
 654          * unicast will leave the filter disabled. */
 655         memset(filter->mask, 0, sizeof(filter->mask));
 656         for (; n < uf.count; n++) {
 657                 if (!is_multicast_ether_addr(addr[n].u)) {
 658                         err = 0; /* no filter */
 659                         goto done;
 660                 }
 661                 addr_hash_set(filter->mask, addr[n].u);
 662         }
 663
 664         /* For ALLMULTI just set the mask to all ones.
 665          * This overrides the mask populated above. */
 666         if ((uf.flags & TUN_FLT_ALLMULTI))
 667                 memset(filter->mask, ~0, sizeof(filter->mask));
 668
 669         /* Now enable the filter */
 670         wmb();
 671         filter->count = nexact;
 672
 673         /* Return the number of exact filters */
 674         err = nexact;
 675
 676 done:
 677         kfree(addr);
 678         return err;
 679 }
 680
 681 /* Returns: 0 - drop, !=0 - accept */
 682 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 683 {
 684         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 685          * at this point. */
 686         struct ethhdr *eh = (struct ethhdr *) skb->data;
 687         int i;
 688
 689         /* Exact match */
 690         for (i = 0; i < filter->count; i++)
 691                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 692                         return 1;
 693
 694         /* Inexact match (multicast only) */
 695         if (is_multicast_ether_addr(eh->h_dest))
 696                 return addr_hash_test(filter->mask, eh->h_dest);
 697
 698         return 0;
 699 }
 700
 701 /*
 702  * Checks whether the packet is accepted or not.
 703  * Returns: 0 - drop, !=0 - accept
 704  */
 705 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 706 {
 707         if (!filter->count)
 708                 return 1;
 709
 710         return run_filter(filter, skb);
 711 }
 712
 713 /* Network device part of the driver */
 714
 715 static const struct ethtool_ops tun_ethtool_ops;
 716
 717 /* Net device detach from fd. */
 718 static void tun_net_uninit(struct net_device *dev)
 719 {
 720         tun_detach_all(dev);
 721 }
 722
 723 /* Net device open. */
 724 static int tun_net_open(struct net_device *dev)
 725 {
 726         netif_tx_start_all_queues(dev);
 727         return 0;
 728 }
 729
 730 /* Net device close. */
 731 static int tun_net_close(struct net_device *dev)
 732 {
 733         netif_tx_stop_all_queues(dev);
 734         return 0;
 735 }
 736
 737 /* Net device start xmit */
 738 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 739 {
 740         struct tun_struct *tun = netdev_priv(dev);
 741         int txq = skb->queue_mapping;
 742         struct tun_file *tfile;
 743         u32 numqueues = 0;
 744
 745         rcu_read_lock();
 746         tfile = rcu_dereference(tun->tfiles[txq]);
 747         numqueues = ACCESS_ONCE(tun->numqueues);
 748
 749         /* Drop packet if interface is not attached */
 750         if (txq >= numqueues)
 751                 goto drop;
 752
 753         if (numqueues == 1) {
 754                 /* Select queue was not called for the skbuff, so we extract the
 755                  * RPS hash and save it into the flow_table here.
 756                  */
 757                 __u32 rxhash;
 758
 759                 rxhash = skb_get_hash(skb);
 760                 if (rxhash) {
 761                         struct tun_flow_entry *e;
 762                         e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
 763                                         rxhash);
 764                         if (e)
 765                                 tun_flow_save_rps_rxhash(e, rxhash);
 766                 }
 767         }
 768
 769         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 770
 771         BUG_ON(!tfile);
 772
 773         /* Drop if the filter does not like it.
 774          * This is a noop if the filter is disabled.
 775          * Filter can be enabled only for the TAP devices. */
 776         if (!check_filter(&tun->txflt, skb))
 777                 goto drop;
 778
 779         if (tfile->socket.sk->sk_filter &&
 780             sk_filter(tfile->socket.sk, skb))
 781                 goto drop;
 782
 783         /* Limit the number of packets queued by dividing txq length with the
 784          * number of queues.
 785          */
 786         if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues
 787                           >= dev->tx_queue_len)
 788                 goto drop;
 789
 790         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 791                 goto drop;
 792
 793         if (skb->sk) {
 794                 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags);
 795                 sw_tx_timestamp(skb);
 796         }
 797
 798         /* Orphan the skb - required as we might hang on to it
 799          * for indefinite time.
 800          */
 801         skb_orphan(skb);
 802
 803         nf_reset(skb);
 804
 805         /* Enqueue packet */
 806         skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
 807
 808         /* Notify and wake up reader process */
 809         if (tfile->flags & TUN_FASYNC)
 810                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
 811         wake_up_interruptible_poll(&tfile->wq.wait, POLLIN |
 812                                    POLLRDNORM | POLLRDBAND);
 813
 814         rcu_read_unlock();
 815         return NETDEV_TX_OK;
 816
 817 drop:
 818         dev->stats.tx_dropped++;
 819         skb_tx_error(skb);
 820         kfree_skb(skb);
 821         rcu_read_unlock();
 822         return NETDEV_TX_OK;
 823 }
 824
 825 static void tun_net_mclist(struct net_device *dev)
 826 {
 827         /*
 828          * This callback is supposed to deal with mc filter in
 829          * _rx_ path and has nothing to do with the _tx_ path.
 830          * In rx path we always accept everything userspace gives us.
 831          */
 832 }
 833
 834 #define MIN_MTU 68
 835 #define MAX_MTU 65535
 836
 837 static int
 838 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 839 {
 840         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 841                 return -EINVAL;
 842         dev->mtu = new_mtu;
 843         return 0;
 844 }
 845
 846 static netdev_features_t tun_net_fix_features(struct net_device *dev,
 847         netdev_features_t features)
 848 {
 849         struct tun_struct *tun = netdev_priv(dev);
 850
 851         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 852 }
 853 #ifdef CONFIG_NET_POLL_CONTROLLER
 854 static void tun_poll_controller(struct net_device *dev)
 855 {
 856         /*
 857          * Tun only receives frames when:
 858          * 1) the char device endpoint gets data from user space
 859          * 2) the tun socket gets a sendmsg call from user space
 860          * Since both of those are synchronous operations, we are guaranteed
 861          * never to have pending data when we poll for it
 862          * so there is nothing to do here but return.
 863          * We need this though so netpoll recognizes us as an interface that
 864          * supports polling, which enables bridge devices in virt setups to
 865          * still use netconsole
 866          */
 867         return;
 868 }
 869 #endif
 870 static const struct net_device_ops tun_netdev_ops = {
 871         .ndo_uninit             = tun_net_uninit,
 872         .ndo_open               = tun_net_open,
 873         .ndo_stop               = tun_net_close,
 874         .ndo_start_xmit         = tun_net_xmit,
 875         .ndo_change_mtu         = tun_net_change_mtu,
 876         .ndo_fix_features       = tun_net_fix_features,
 877         .ndo_select_queue       = tun_select_queue,
 878 #ifdef CONFIG_NET_POLL_CONTROLLER
 879         .ndo_poll_controller    = tun_poll_controller,
 880 #endif
 881 };
 882
 883 static const struct net_device_ops tap_netdev_ops = {
 884         .ndo_uninit             = tun_net_uninit,
 885         .ndo_open               = tun_net_open,
 886         .ndo_stop               = tun_net_close,
 887         .ndo_start_xmit         = tun_net_xmit,
 888         .ndo_change_mtu         = tun_net_change_mtu,
 889         .ndo_fix_features       = tun_net_fix_features,
 890         .ndo_set_rx_mode        = tun_net_mclist,
 891         .ndo_set_mac_address    = eth_mac_addr,
 892         .ndo_validate_addr      = eth_validate_addr,
 893         .ndo_select_queue       = tun_select_queue,
 894 #ifdef CONFIG_NET_POLL_CONTROLLER
 895         .ndo_poll_controller    = tun_poll_controller,
 896 #endif
 897 };
 898
 899 static void tun_flow_init(struct tun_struct *tun)
 900 {
 901         int i;
 902
 903         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
 904                 INIT_HLIST_HEAD(&tun->flows[i]);
 905
 906         tun->ageing_time = TUN_FLOW_EXPIRE;
 907         setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
 908         mod_timer(&tun->flow_gc_timer,
 909                   round_jiffies_up(jiffies + tun->ageing_time));
 910 }
 911
 912 static void tun_flow_uninit(struct tun_struct *tun)
 913 {
 914         del_timer_sync(&tun->flow_gc_timer);
 915         tun_flow_flush(tun);
 916 }
 917
 918 /* Initialize net device. */
 919 static void tun_net_init(struct net_device *dev)
 920 {
 921         struct tun_struct *tun = netdev_priv(dev);
 922
 923         switch (tun->flags & TUN_TYPE_MASK) {
 924         case TUN_TUN_DEV:
 925                 dev->netdev_ops = &tun_netdev_ops;
 926
 927                 /* Point-to-Point TUN Device */
 928                 dev->hard_header_len = 0;
 929                 dev->addr_len = 0;
 930                 dev->mtu = 1500;
 931
 932                 /* Zero header length */
 933                 dev->type = ARPHRD_NONE;
 934                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 935                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 936                 break;
 937
 938         case TUN_TAP_DEV:
 939                 dev->netdev_ops = &tap_netdev_ops;
 940                 /* Ethernet TAP Device */
 941                 ether_setup(dev);
 942                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 943                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
 944
 945                 eth_hw_addr_random(dev);
 946
 947                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 948                 break;
 949         }
 950 }
 951
 952 /* Character device part */
 953
 954 /* Poll */
 955 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
 956 {
 957         struct tun_file *tfile = file->private_data;
 958         struct tun_struct *tun = __tun_get(tfile);
 959         struct sock *sk;
 960         unsigned int mask = 0;
 961
 962         if (!tun)
 963                 return POLLERR;
 964
 965         sk = tfile->socket.sk;
 966
 967         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
 968
 969         poll_wait(file, &tfile->wq.wait, wait);
 970
 971         if (!skb_queue_empty(&sk->sk_receive_queue))
 972                 mask |= POLLIN | POLLRDNORM;
 973
 974         if (sock_writeable(sk) ||
 975             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 976              sock_writeable(sk)))
 977                 mask |= POLLOUT | POLLWRNORM;
 978
 979         if (tun->dev->reg_state != NETREG_REGISTERED)
 980                 mask = POLLERR;
 981
 982         tun_put(tun);
 983         return mask;
 984 }
 985
 986 /* prepad is the amount to reserve at front.  len is length after that.
 987  * linear is a hint as to how much to copy (usually headers). */
 988 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
 989                                      size_t prepad, size_t len,
 990                                      size_t linear, int noblock)
 991 {
 992         struct sock *sk = tfile->socket.sk;
 993         struct sk_buff *skb;
 994         int err;
 995
 996         /* Under a page?  Don't bother with paged skb. */
 997         if (prepad + len < PAGE_SIZE || !linear)
 998                 linear = len;
 999
1000         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1001                                    &err, 0);
1002         if (!skb)
1003                 return ERR_PTR(err);
1004
1005         skb_reserve(skb, prepad);
1006         skb_put(skb, linear);
1007         skb->data_len = len - linear;
1008         skb->len += len - linear;
1009
1010         return skb;
1011 }
1012
1013 /* Get packet from user space buffer */
1014 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1015                             void *msg_control, const struct iovec *iv,
1016                             size_t total_len, size_t count, int noblock)
1017 {
1018         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1019         struct sk_buff *skb;
1020         size_t len = total_len, align = NET_SKB_PAD, linear;
1021         struct virtio_net_hdr gso = { 0 };
1022         int good_linear;
1023         int offset = 0;
1024         int copylen;
1025         bool zerocopy = false;
1026         int err;
1027         u32 rxhash;
1028
1029         if (!(tun->flags & TUN_NO_PI)) {
1030                 if (len < sizeof(pi))
1031                         return -EINVAL;
1032                 len -= sizeof(pi);
1033
1034                 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
1035                         return -EFAULT;
1036                 offset += sizeof(pi);
1037         }
1038
1039         if (tun->flags & TUN_VNET_HDR) {
1040                 if (len < tun->vnet_hdr_sz)
1041                         return -EINVAL;
1042                 len -= tun->vnet_hdr_sz;
1043
1044                 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
1045                         return -EFAULT;
1046
1047                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1048                     gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
1049                         gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
1050
1051                 if (gso.hdr_len > len)
1052                         return -EINVAL;
1053                 offset += tun->vnet_hdr_sz;
1054         }
1055
1056         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
1057                 align += NET_IP_ALIGN;
1058                 if (unlikely(len < ETH_HLEN ||
1059                              (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
1060                         return -EINVAL;
1061         }
1062
1063         good_linear = SKB_MAX_HEAD(align);
1064
1065         if (msg_control) {
1066                 /* There are 256 bytes to be copied in skb, so there is
1067                  * enough room for skb expand head in case it is used.
1068                  * The rest of the buffer is mapped from userspace.
1069                  */
1070                 copylen = gso.hdr_len ? gso.hdr_len : GOODCOPY_LEN;
1071                 if (copylen > good_linear)
1072                         copylen = good_linear;
1073                 linear = copylen;
1074                 if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS)
1075                         zerocopy = true;
1076         }
1077
1078         if (!zerocopy) {
1079                 copylen = len;
1080                 if (gso.hdr_len > good_linear)
1081                         linear = good_linear;
1082                 else
1083                         linear = gso.hdr_len;
1084         }
1085
1086         skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1087         if (IS_ERR(skb)) {
1088                 if (PTR_ERR(skb) != -EAGAIN)
1089                         tun->dev->stats.rx_dropped++;
1090                 return PTR_ERR(skb);
1091         }
1092
1093         if (zerocopy)
1094                 err = zerocopy_sg_from_iovec(skb, iv, offset, count);
1095         else {
1096                 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
1097                 if (!err && msg_control) {
1098                         struct ubuf_info *uarg = msg_control;
1099                         uarg->callback(uarg, false);
1100                 }
1101         }
1102
1103         if (err) {
1104                 tun->dev->stats.rx_dropped++;
1105                 kfree_skb(skb);
1106                 return -EFAULT;
1107         }
1108
1109         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1110                 if (!skb_partial_csum_set(skb, gso.csum_start,
1111                                           gso.csum_offset)) {
1112                         tun->dev->stats.rx_frame_errors++;
1113                         kfree_skb(skb);
1114                         return -EINVAL;
1115                 }
1116         }
1117
1118         switch (tun->flags & TUN_TYPE_MASK) {
1119         case TUN_TUN_DEV:
1120                 if (tun->flags & TUN_NO_PI) {
1121                         switch (skb->data[0] & 0xf0) {
1122                         case 0x40:
1123                                 pi.proto = htons(ETH_P_IP);
1124                                 break;
1125                         case 0x60:
1126                                 pi.proto = htons(ETH_P_IPV6);
1127                                 break;
1128                         default:
1129                                 tun->dev->stats.rx_dropped++;
1130                                 kfree_skb(skb);
1131                                 return -EINVAL;
1132                         }
1133                 }
1134
1135                 skb_reset_mac_header(skb);
1136                 skb->protocol = pi.proto;
1137                 skb->dev = tun->dev;
1138                 break;
1139         case TUN_TAP_DEV:
1140                 skb->protocol = eth_type_trans(skb, tun->dev);
1141                 break;
1142         }
1143
1144         skb_reset_network_header(skb);
1145
1146         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1147                 pr_debug("GSO!\n");
1148                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1149                 case VIRTIO_NET_HDR_GSO_TCPV4:
1150                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1151                         break;
1152                 case VIRTIO_NET_HDR_GSO_TCPV6:
1153                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1154                         break;
1155                 case VIRTIO_NET_HDR_GSO_UDP:
1156                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1157                         if (skb->protocol == htons(ETH_P_IPV6))
1158                                 ipv6_proxy_select_ident(skb);
1159                         break;
1160                 default:
1161                         tun->dev->stats.rx_frame_errors++;
1162                         kfree_skb(skb);
1163                         return -EINVAL;
1164                 }
1165
1166                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1167                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1168
1169                 skb_shinfo(skb)->gso_size = gso.gso_size;
1170                 if (skb_shinfo(skb)->gso_size == 0) {
1171                         tun->dev->stats.rx_frame_errors++;
1172                         kfree_skb(skb);
1173                         return -EINVAL;
1174                 }
1175
1176                 /* Header must be checked, and gso_segs computed. */
1177                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1178                 skb_shinfo(skb)->gso_segs = 0;
1179         }
1180
1181         /* copy skb_ubuf_info for callback when skb has no error */
1182         if (zerocopy) {
1183                 skb_shinfo(skb)->destructor_arg = msg_control;
1184                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1185                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1186         }
1187
1188         skb_probe_transport_header(skb, 0);
1189
1190         rxhash = skb_get_hash(skb);
1191         netif_rx_ni(skb);
1192
1193         tun->dev->stats.rx_packets++;
1194         tun->dev->stats.rx_bytes += len;
1195
1196         tun_flow_update(tun, rxhash, tfile);
1197         return total_len;
1198 }
1199
1200 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
1201                               unsigned long count, loff_t pos)
1202 {
1203         struct file *file = iocb->ki_filp;
1204         struct tun_struct *tun = tun_get(file);
1205         struct tun_file *tfile = file->private_data;
1206         ssize_t result;
1207
1208         if (!tun)
1209                 return -EBADFD;
1210
1211         tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
1212
1213         result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count),
1214                               count, file->f_flags & O_NONBLOCK);
1215
1216         tun_put(tun);
1217         return result;
1218 }
1219
1220 /* Put packet to the user space buffer */
1221 static ssize_t tun_put_user(struct tun_struct *tun,
1222                             struct tun_file *tfile,
1223                             struct sk_buff *skb,
1224                             const struct iovec *iv, int len)
1225 {
1226         struct tun_pi pi = { 0, skb->protocol };
1227         ssize_t total = 0;
1228         int vlan_offset = 0, copied;
1229         int vlan_hlen = 0;
1230
1231         if (vlan_tx_tag_present(skb))
1232                 vlan_hlen = VLAN_HLEN;
1233
1234         if (!(tun->flags & TUN_NO_PI)) {
1235                 if ((len -= sizeof(pi)) < 0)
1236                         return -EINVAL;
1237
1238                 if (len < skb->len) {
1239                         /* Packet will be striped */
1240                         pi.flags |= TUN_PKT_STRIP;
1241                 }
1242
1243                 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
1244                         return -EFAULT;
1245                 total += sizeof(pi);
1246         }
1247
1248         if (tun->flags & TUN_VNET_HDR) {
1249                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1250                 if ((len -= tun->vnet_hdr_sz) < 0)
1251                         return -EINVAL;
1252
1253                 if (skb_is_gso(skb)) {
1254                         struct skb_shared_info *sinfo = skb_shinfo(skb);
1255
1256                         /* This is a hint as to how much should be linear. */
1257                         gso.hdr_len = skb_headlen(skb);
1258                         gso.gso_size = sinfo->gso_size;
1259                         if (sinfo->gso_type & SKB_GSO_TCPV4)
1260                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1261                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
1262                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1263                         else if (sinfo->gso_type & SKB_GSO_UDP)
1264                                 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1265                         else {
1266                                 pr_err("unexpected GSO type: "
1267                                        "0x%x, gso_size %d, hdr_len %d\n",
1268                                        sinfo->gso_type, gso.gso_size,
1269                                        gso.hdr_len);
1270                                 print_hex_dump(KERN_ERR, "tun: ",
1271                                                DUMP_PREFIX_NONE,
1272                                                16, 1, skb->head,
1273                                                min((int)gso.hdr_len, 64), true);
1274                                 WARN_ON_ONCE(1);
1275                                 return -EINVAL;
1276                         }
1277                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1278                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1279                 } else
1280                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1281
1282                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1283                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1284                         gso.csum_start = skb_checksum_start_offset(skb) +
1285                                          vlan_hlen;
1286                         gso.csum_offset = skb->csum_offset;
1287                 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1288                         gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1289                 } /* else everything is zero */
1290
1291                 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
1292                                                sizeof(gso))))
1293                         return -EFAULT;
1294                 total += tun->vnet_hdr_sz;
1295         }
1296
1297         copied = total;
1298         len = min_t(int, skb->len + vlan_hlen, len);
1299         total += skb->len + vlan_hlen;
1300         if (vlan_hlen) {
1301                 int copy, ret;
1302                 struct {
1303                         __be16 h_vlan_proto;
1304                         __be16 h_vlan_TCI;
1305                 } veth;
1306
1307                 veth.h_vlan_proto = skb->vlan_proto;
1308                 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb));
1309
1310                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1311
1312                 copy = min_t(int, vlan_offset, len);
1313                 ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy);
1314                 len -= copy;
1315                 copied += copy;
1316                 if (ret || !len)
1317                         goto done;
1318
1319                 copy = min_t(int, sizeof(veth), len);
1320                 ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy);
1321                 len -= copy;
1322                 copied += copy;
1323                 if (ret || !len)
1324                         goto done;
1325         }
1326
1327         skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len);
1328
1329 done:
1330         tun->dev->stats.tx_packets++;
1331         tun->dev->stats.tx_bytes += len;
1332
1333         return total;
1334 }
1335
1336 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1337                            const struct iovec *iv, ssize_t len, int noblock)
1338 {
1339         DECLARE_WAITQUEUE(wait, current);
1340         struct sk_buff *skb;
1341         ssize_t ret = 0;
1342
1343         tun_debug(KERN_INFO, tun, "tun_do_read\n");
1344
1345         if (unlikely(!noblock))
1346                 add_wait_queue(&tfile->wq.wait, &wait);
1347         while (len) {
1348                 if (unlikely(!noblock))
1349                         current->state = TASK_INTERRUPTIBLE;
1350
1351                 /* Read frames from the queue */
1352                 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) {
1353                         if (noblock) {
1354                                 ret = -EAGAIN;
1355                                 break;
1356                         }
1357                         if (signal_pending(current)) {
1358                                 ret = -ERESTARTSYS;
1359                                 break;
1360                         }
1361                         if (tun->dev->reg_state != NETREG_REGISTERED) {
1362                                 ret = -EIO;
1363                                 break;
1364                         }
1365
1366                         /* Nothing to read, let's sleep */
1367                         schedule();
1368                         continue;
1369                 }
1370
1371                 ret = tun_put_user(tun, tfile, skb, iv, len);
1372                 kfree_skb(skb);
1373                 break;
1374         }
1375
1376         if (unlikely(!noblock)) {
1377                 current->state = TASK_RUNNING;
1378                 remove_wait_queue(&tfile->wq.wait, &wait);
1379         }
1380
1381         return ret;
1382 }
1383
1384 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1385                             unsigned long count, loff_t pos)
1386 {
1387         struct file *file = iocb->ki_filp;
1388         struct tun_file *tfile = file->private_data;
1389         struct tun_struct *tun = __tun_get(tfile);
1390         ssize_t len, ret;
1391
1392         if (!tun)
1393                 return -EBADFD;
1394         len = iov_length(iv, count);
1395         if (len < 0) {
1396                 ret = -EINVAL;
1397                 goto out;
1398         }
1399
1400         ret = tun_do_read(tun, tfile, iv, len,
1401                           file->f_flags & O_NONBLOCK);
1402         ret = min_t(ssize_t, ret, len);
1403         if (ret > 0)
1404                 iocb->ki_pos = ret;
1405 out:
1406         tun_put(tun);
1407         return ret;
1408 }
1409
1410 static void tun_free_netdev(struct net_device *dev)
1411 {
1412         struct tun_struct *tun = netdev_priv(dev);
1413
1414         BUG_ON(!(list_empty(&tun->disabled)));
1415         tun_flow_uninit(tun);
1416         security_tun_dev_free_security(tun->security);
1417         free_netdev(dev);
1418 }
1419
1420 static void tun_setup(struct net_device *dev)
1421 {
1422         struct tun_struct *tun = netdev_priv(dev);
1423
1424         tun->owner = INVALID_UID;
1425         tun->group = INVALID_GID;
1426
1427         dev->ethtool_ops = &tun_ethtool_ops;
1428         dev->destructor = tun_free_netdev;
1429 }
1430
1431 /* Trivial set of netlink ops to allow deleting tun or tap
1432  * device with netlink.
1433  */
1434 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1435 {
1436         return -EINVAL;
1437 }
1438
1439 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1440         .kind           = DRV_NAME,
1441         .priv_size      = sizeof(struct tun_struct),
1442         .setup          = tun_setup,
1443         .validate       = tun_validate,
1444 };
1445
1446 static void tun_sock_write_space(struct sock *sk)
1447 {
1448         struct tun_file *tfile;
1449         wait_queue_head_t *wqueue;
1450
1451         if (!sock_writeable(sk))
1452                 return;
1453
1454         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1455                 return;
1456
1457         wqueue = sk_sleep(sk);
1458         if (wqueue && waitqueue_active(wqueue))
1459                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1460                                                 POLLWRNORM | POLLWRBAND);
1461
1462         tfile = container_of(sk, struct tun_file, sk);
1463         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1464 }
1465
1466 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1467                        struct msghdr *m, size_t total_len)
1468 {
1469         int ret;
1470         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1471         struct tun_struct *tun = __tun_get(tfile);
1472
1473         if (!tun)
1474                 return -EBADFD;
1475         ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len,
1476                            m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1477         tun_put(tun);
1478         return ret;
1479 }
1480
1481 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1482                        struct msghdr *m, size_t total_len,
1483                        int flags)
1484 {
1485         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1486         struct tun_struct *tun = __tun_get(tfile);
1487         int ret;
1488
1489         if (!tun)
1490                 return -EBADFD;
1491
1492         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1493                 ret = -EINVAL;
1494                 goto out;
1495         }
1496         if (flags & MSG_ERRQUEUE) {
1497                 ret = sock_recv_errqueue(sock->sk, m, total_len,
1498                                          SOL_PACKET, TUN_TX_TIMESTAMP);
1499                 goto out;
1500         }
1501         ret = tun_do_read(tun, tfile, m->msg_iov, total_len,
1502                           flags & MSG_DONTWAIT);
1503         if (ret > total_len) {
1504                 m->msg_flags |= MSG_TRUNC;
1505                 ret = flags & MSG_TRUNC ? ret : total_len;
1506         }
1507 out:
1508         tun_put(tun);
1509         return ret;
1510 }
1511
1512 static int tun_release(struct socket *sock)
1513 {
1514         if (sock->sk)
1515                 sock_put(sock->sk);
1516         return 0;
1517 }
1518
1519 /* Ops structure to mimic raw sockets with tun */
1520 static const struct proto_ops tun_socket_ops = {
1521         .sendmsg = tun_sendmsg,
1522         .recvmsg = tun_recvmsg,
1523         .release = tun_release,
1524 };
1525
1526 static struct proto tun_proto = {
1527         .name           = "tun",
1528         .owner          = THIS_MODULE,
1529         .obj_size       = sizeof(struct tun_file),
1530 };
1531
1532 static int tun_flags(struct tun_struct *tun)
1533 {
1534         int flags = 0;
1535
1536         if (tun->flags & TUN_TUN_DEV)
1537                 flags |= IFF_TUN;
1538         else
1539                 flags |= IFF_TAP;
1540
1541         if (tun->flags & TUN_NO_PI)
1542                 flags |= IFF_NO_PI;
1543
1544         /* This flag has no real effect.  We track the value for backwards
1545          * compatibility.
1546          */
1547         if (tun->flags & TUN_ONE_QUEUE)
1548                 flags |= IFF_ONE_QUEUE;
1549
1550         if (tun->flags & TUN_VNET_HDR)
1551                 flags |= IFF_VNET_HDR;
1552
1553         if (tun->flags & TUN_TAP_MQ)
1554                 flags |= IFF_MULTI_QUEUE;
1555
1556         if (tun->flags & TUN_PERSIST)
1557                 flags |= IFF_PERSIST;
1558
1559         return flags;
1560 }
1561
1562 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1563                               char *buf)
1564 {
1565         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1566         return sprintf(buf, "0x%x\n", tun_flags(tun));
1567 }
1568
1569 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1570                               char *buf)
1571 {
1572         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1573         return uid_valid(tun->owner)?
1574                 sprintf(buf, "%u\n",
1575                         from_kuid_munged(current_user_ns(), tun->owner)):
1576                 sprintf(buf, "-1\n");
1577 }
1578
1579 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1580                               char *buf)
1581 {
1582         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1583         return gid_valid(tun->group) ?
1584                 sprintf(buf, "%u\n",
1585                         from_kgid_munged(current_user_ns(), tun->group)):
1586                 sprintf(buf, "-1\n");
1587 }
1588
1589 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1590 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1591 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1592
1593 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1594 {
1595         struct tun_struct *tun;
1596         struct tun_file *tfile = file->private_data;
1597         struct net_device *dev;
1598         int err;
1599
1600         if (tfile->detached)
1601                 return -EINVAL;
1602
1603         dev = __dev_get_by_name(net, ifr->ifr_name);
1604         if (dev) {
1605                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1606                         return -EBUSY;
1607                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1608                         tun = netdev_priv(dev);
1609                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1610                         tun = netdev_priv(dev);
1611                 else
1612                         return -EINVAL;
1613
1614                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1615                     !!(tun->flags & TUN_TAP_MQ))
1616                         return -EINVAL;
1617
1618                 if (tun_not_capable(tun))
1619                         return -EPERM;
1620                 err = security_tun_dev_open(tun->security);
1621                 if (err < 0)
1622                         return err;
1623
1624                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1625                 if (err < 0)
1626                         return err;
1627
1628                 if (tun->flags & TUN_TAP_MQ &&
1629                     (tun->numqueues + tun->numdisabled > 1)) {
1630                         /* One or more queue has already been attached, no need
1631                          * to initialize the device again.
1632                          */
1633                         return 0;
1634                 }
1635         }
1636         else {
1637                 char *name;
1638                 unsigned long flags = 0;
1639                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1640                              MAX_TAP_QUEUES : 1;
1641
1642                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1643                         return -EPERM;
1644                 err = security_tun_dev_create();
1645                 if (err < 0)
1646                         return err;
1647
1648                 /* Set dev type */
1649                 if (ifr->ifr_flags & IFF_TUN) {
1650                         /* TUN device */
1651                         flags |= TUN_TUN_DEV;
1652                         name = "tun%d";
1653                 } else if (ifr->ifr_flags & IFF_TAP) {
1654                         /* TAP device */
1655                         flags |= TUN_TAP_DEV;
1656                         name = "tap%d";
1657                 } else
1658                         return -EINVAL;
1659
1660                 if (*ifr->ifr_name)
1661                         name = ifr->ifr_name;
1662
1663                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1664                                        tun_setup, queues, queues);
1665
1666                 if (!dev)
1667                         return -ENOMEM;
1668
1669                 dev_net_set(dev, net);
1670                 dev->rtnl_link_ops = &tun_link_ops;
1671                 dev->ifindex = tfile->ifindex;
1672
1673                 tun = netdev_priv(dev);
1674                 tun->dev = dev;
1675                 tun->flags = flags;
1676                 tun->txflt.count = 0;
1677                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1678
1679                 tun->filter_attached = false;
1680                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1681
1682                 spin_lock_init(&tun->lock);
1683
1684                 err = security_tun_dev_alloc_security(&tun->security);
1685                 if (err < 0)
1686                         goto err_free_dev;
1687
1688                 tun_net_init(dev);
1689                 tun_flow_init(tun);
1690
1691                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1692                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1693                                    NETIF_F_HW_VLAN_STAG_TX;
1694                 dev->features = dev->hw_features;
1695                 dev->vlan_features = dev->features &
1696                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
1697                                        NETIF_F_HW_VLAN_STAG_TX);
1698
1699                 INIT_LIST_HEAD(&tun->disabled);
1700                 err = tun_attach(tun, file, false);
1701                 if (err < 0)
1702                         goto err_free_flow;
1703
1704                 err = register_netdevice(tun->dev);
1705                 if (err < 0)
1706                         goto err_detach;
1707
1708                 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1709                     device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1710                     device_create_file(&tun->dev->dev, &dev_attr_group))
1711                         pr_err("Failed to create tun sysfs files\n");
1712         }
1713
1714         netif_carrier_on(tun->dev);
1715
1716         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1717
1718         if (ifr->ifr_flags & IFF_NO_PI)
1719                 tun->flags |= TUN_NO_PI;
1720         else
1721                 tun->flags &= ~TUN_NO_PI;
1722
1723         /* This flag has no real effect.  We track the value for backwards
1724          * compatibility.
1725          */
1726         if (ifr->ifr_flags & IFF_ONE_QUEUE)
1727                 tun->flags |= TUN_ONE_QUEUE;
1728         else
1729                 tun->flags &= ~TUN_ONE_QUEUE;
1730
1731         if (ifr->ifr_flags & IFF_VNET_HDR)
1732                 tun->flags |= TUN_VNET_HDR;
1733         else
1734                 tun->flags &= ~TUN_VNET_HDR;
1735
1736         if (ifr->ifr_flags & IFF_MULTI_QUEUE)
1737                 tun->flags |= TUN_TAP_MQ;
1738         else
1739                 tun->flags &= ~TUN_TAP_MQ;
1740
1741         /* Make sure persistent devices do not get stuck in
1742          * xoff state.
1743          */
1744         if (netif_running(tun->dev))
1745                 netif_tx_wake_all_queues(tun->dev);
1746
1747         strcpy(ifr->ifr_name, tun->dev->name);
1748         return 0;
1749
1750 err_detach:
1751         tun_detach_all(dev);
1752 err_free_flow:
1753         tun_flow_uninit(tun);
1754         security_tun_dev_free_security(tun->security);
1755 err_free_dev:
1756         free_netdev(dev);
1757         return err;
1758 }
1759
1760 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1761                        struct ifreq *ifr)
1762 {
1763         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1764
1765         strcpy(ifr->ifr_name, tun->dev->name);
1766
1767         ifr->ifr_flags = tun_flags(tun);
1768
1769 }
1770
1771 /* This is like a cut-down ethtool ops, except done via tun fd so no
1772  * privs required. */
1773 static int set_offload(struct tun_struct *tun, unsigned long arg)
1774 {
1775         netdev_features_t features = 0;
1776
1777         if (arg & TUN_F_CSUM) {
1778                 features |= NETIF_F_HW_CSUM;
1779                 arg &= ~TUN_F_CSUM;
1780
1781                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1782                         if (arg & TUN_F_TSO_ECN) {
1783                                 features |= NETIF_F_TSO_ECN;
1784                                 arg &= ~TUN_F_TSO_ECN;
1785                         }
1786                         if (arg & TUN_F_TSO4)
1787                                 features |= NETIF_F_TSO;
1788                         if (arg & TUN_F_TSO6)
1789                                 features |= NETIF_F_TSO6;
1790                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1791                 }
1792
1793                 if (arg & TUN_F_UFO) {
1794                         features |= NETIF_F_UFO;
1795                         arg &= ~TUN_F_UFO;
1796                 }
1797         }
1798
1799         /* This gives the user a way to test for new features in future by
1800          * trying to set them. */
1801         if (arg)
1802                 return -EINVAL;
1803
1804         tun->set_features = features;
1805         netdev_update_features(tun->dev);
1806
1807         return 0;
1808 }
1809
1810 static void tun_detach_filter(struct tun_struct *tun, int n)
1811 {
1812         int i;
1813         struct tun_file *tfile;
1814
1815         for (i = 0; i < n; i++) {
1816                 tfile = rtnl_dereference(tun->tfiles[i]);
1817                 sk_detach_filter(tfile->socket.sk);
1818         }
1819
1820         tun->filter_attached = false;
1821 }
1822
1823 static int tun_attach_filter(struct tun_struct *tun)
1824 {
1825         int i, ret = 0;
1826         struct tun_file *tfile;
1827
1828         for (i = 0; i < tun->numqueues; i++) {
1829                 tfile = rtnl_dereference(tun->tfiles[i]);
1830                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1831                 if (ret) {
1832                         tun_detach_filter(tun, i);
1833                         return ret;
1834                 }
1835         }
1836
1837         tun->filter_attached = true;
1838         return ret;
1839 }
1840
1841 static void tun_set_sndbuf(struct tun_struct *tun)
1842 {
1843         struct tun_file *tfile;
1844         int i;
1845
1846         for (i = 0; i < tun->numqueues; i++) {
1847                 tfile = rtnl_dereference(tun->tfiles[i]);
1848                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1849         }
1850 }
1851
1852 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1853 {
1854         struct tun_file *tfile = file->private_data;
1855         struct tun_struct *tun;
1856         int ret = 0;
1857
1858         rtnl_lock();
1859
1860         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1861                 tun = tfile->detached;
1862                 if (!tun) {
1863                         ret = -EINVAL;
1864                         goto unlock;
1865                 }
1866                 ret = security_tun_dev_attach_queue(tun->security);
1867                 if (ret < 0)
1868                         goto unlock;
1869                 ret = tun_attach(tun, file, false);
1870         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1871                 tun = rtnl_dereference(tfile->tun);
1872                 if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached)
1873                         ret = -EINVAL;
1874                 else
1875                         __tun_detach(tfile, false);
1876         } else
1877                 ret = -EINVAL;
1878
1879 unlock:
1880         rtnl_unlock();
1881         return ret;
1882 }
1883
1884 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1885                             unsigned long arg, int ifreq_len)
1886 {
1887         struct tun_file *tfile = file->private_data;
1888         struct tun_struct *tun;
1889         void __user* argp = (void __user*)arg;
1890         struct ifreq ifr;
1891         kuid_t owner;
1892         kgid_t group;
1893         int sndbuf;
1894         int vnet_hdr_sz;
1895         unsigned int ifindex;
1896         int ret;
1897
1898         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1899                 if (copy_from_user(&ifr, argp, ifreq_len))
1900                         return -EFAULT;
1901         } else {
1902                 memset(&ifr, 0, sizeof(ifr));
1903         }
1904         if (cmd == TUNGETFEATURES) {
1905                 /* Currently this just means: "what IFF flags are valid?".
1906                  * This is needed because we never checked for invalid flags on
1907                  * TUNSETIFF. */
1908                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1909                                 IFF_VNET_HDR | IFF_MULTI_QUEUE,
1910                                 (unsigned int __user*)argp);
1911         } else if (cmd == TUNSETQUEUE)
1912                 return tun_set_queue(file, &ifr);
1913
1914         ret = 0;
1915         rtnl_lock();
1916
1917         tun = __tun_get(tfile);
1918         if (cmd == TUNSETIFF && !tun) {
1919                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1920
1921                 ret = tun_set_iff(tfile->net, file, &ifr);
1922
1923                 if (ret)
1924                         goto unlock;
1925
1926                 if (copy_to_user(argp, &ifr, ifreq_len))
1927                         ret = -EFAULT;
1928                 goto unlock;
1929         }
1930         if (cmd == TUNSETIFINDEX) {
1931                 ret = -EPERM;
1932                 if (tun)
1933                         goto unlock;
1934
1935                 ret = -EFAULT;
1936                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
1937                         goto unlock;
1938
1939                 ret = 0;
1940                 tfile->ifindex = ifindex;
1941                 goto unlock;
1942         }
1943
1944         ret = -EBADFD;
1945         if (!tun)
1946                 goto unlock;
1947
1948         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1949
1950         ret = 0;
1951         switch (cmd) {
1952         case TUNGETIFF:
1953                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1954
1955                 if (tfile->detached)
1956                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
1957                 if (!tfile->socket.sk->sk_filter)
1958                         ifr.ifr_flags |= IFF_NOFILTER;
1959
1960                 if (copy_to_user(argp, &ifr, ifreq_len))
1961                         ret = -EFAULT;
1962                 break;
1963
1964         case TUNSETNOCSUM:
1965                 /* Disable/Enable checksum */
1966
1967                 /* [unimplemented] */
1968                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1969                           arg ? "disabled" : "enabled");
1970                 break;
1971
1972         case TUNSETPERSIST:
1973                 /* Disable/Enable persist mode. Keep an extra reference to the
1974                  * module to prevent the module being unprobed.
1975                  */
1976                 if (arg && !(tun->flags & TUN_PERSIST)) {
1977                         tun->flags |= TUN_PERSIST;
1978                         __module_get(THIS_MODULE);
1979                 }
1980                 if (!arg && (tun->flags & TUN_PERSIST)) {
1981                         tun->flags &= ~TUN_PERSIST;
1982                         module_put(THIS_MODULE);
1983                 }
1984
1985                 tun_debug(KERN_INFO, tun, "persist %s\n",
1986                           arg ? "enabled" : "disabled");
1987                 break;
1988
1989         case TUNSETOWNER:
1990                 /* Set owner of the device */
1991                 owner = make_kuid(current_user_ns(), arg);
1992                 if (!uid_valid(owner)) {
1993                         ret = -EINVAL;
1994                         break;
1995                 }
1996                 tun->owner = owner;
1997                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
1998                           from_kuid(&init_user_ns, tun->owner));
1999                 break;
2000
2001         case TUNSETGROUP:
2002                 /* Set group of the device */
2003                 group = make_kgid(current_user_ns(), arg);
2004                 if (!gid_valid(group)) {
2005                         ret = -EINVAL;
2006                         break;
2007                 }
2008                 tun->group = group;
2009                 tun_debug(KERN_INFO, tun, "group set to %u\n",
2010                           from_kgid(&init_user_ns, tun->group));
2011                 break;
2012
2013         case TUNSETLINK:
2014                 /* Only allow setting the type when the interface is down */
2015                 if (tun->dev->flags & IFF_UP) {
2016                         tun_debug(KERN_INFO, tun,
2017                                   "Linktype set failed because interface is up\n");
2018                         ret = -EBUSY;
2019                 } else {
2020                         tun->dev->type = (int) arg;
2021                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2022                                   tun->dev->type);
2023                         ret = 0;
2024                 }
2025                 break;
2026
2027 #ifdef TUN_DEBUG
2028         case TUNSETDEBUG:
2029                 tun->debug = arg;
2030                 break;
2031 #endif
2032         case TUNSETOFFLOAD:
2033                 ret = set_offload(tun, arg);
2034                 break;
2035
2036         case TUNSETTXFILTER:
2037                 /* Can be set only for TAPs */
2038                 ret = -EINVAL;
2039                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2040                         break;
2041                 ret = update_filter(&tun->txflt, (void __user *)arg);
2042                 break;
2043
2044         case SIOCGIFHWADDR:
2045                 /* Get hw address */
2046                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2047                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2048                 if (copy_to_user(argp, &ifr, ifreq_len))
2049                         ret = -EFAULT;
2050                 break;
2051
2052         case SIOCSIFHWADDR:
2053                 /* Set hw address */
2054                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2055                           ifr.ifr_hwaddr.sa_data);
2056
2057                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2058                 break;
2059
2060         case TUNGETSNDBUF:
2061                 sndbuf = tfile->socket.sk->sk_sndbuf;
2062                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2063                         ret = -EFAULT;
2064                 break;
2065
2066         case TUNSETSNDBUF:
2067                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2068                         ret = -EFAULT;
2069                         break;
2070                 }
2071
2072                 tun->sndbuf = sndbuf;
2073                 tun_set_sndbuf(tun);
2074                 break;
2075
2076         case TUNGETVNETHDRSZ:
2077                 vnet_hdr_sz = tun->vnet_hdr_sz;
2078                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2079                         ret = -EFAULT;
2080                 break;
2081
2082         case TUNSETVNETHDRSZ:
2083                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2084                         ret = -EFAULT;
2085                         break;
2086                 }
2087                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2088                         ret = -EINVAL;
2089                         break;
2090                 }
2091
2092                 tun->vnet_hdr_sz = vnet_hdr_sz;
2093                 break;
2094
2095         case TUNATTACHFILTER:
2096                 /* Can be set only for TAPs */
2097                 ret = -EINVAL;
2098                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2099                         break;
2100                 ret = -EFAULT;
2101                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2102                         break;
2103
2104                 ret = tun_attach_filter(tun);
2105                 break;
2106
2107         case TUNDETACHFILTER:
2108                 /* Can be set only for TAPs */
2109                 ret = -EINVAL;
2110                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2111                         break;
2112                 ret = 0;
2113                 tun_detach_filter(tun, tun->numqueues);
2114                 break;
2115
2116         case TUNGETFILTER:
2117                 ret = -EINVAL;
2118                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2119                         break;
2120                 ret = -EFAULT;
2121                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2122                         break;
2123                 ret = 0;
2124                 break;
2125
2126         default:
2127                 ret = -EINVAL;
2128                 break;
2129         }
2130
2131 unlock:
2132         rtnl_unlock();
2133         if (tun)
2134                 tun_put(tun);
2135         return ret;
2136 }
2137
2138 static long tun_chr_ioctl(struct file *file,
2139                           unsigned int cmd, unsigned long arg)
2140 {
2141         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2142 }
2143
2144 #ifdef CONFIG_COMPAT
2145 static long tun_chr_compat_ioctl(struct file *file,
2146                          unsigned int cmd, unsigned long arg)
2147 {
2148         switch (cmd) {
2149         case TUNSETIFF:
2150         case TUNGETIFF:
2151         case TUNSETTXFILTER:
2152         case TUNGETSNDBUF:
2153         case TUNSETSNDBUF:
2154         case SIOCGIFHWADDR:
2155         case SIOCSIFHWADDR:
2156                 arg = (unsigned long)compat_ptr(arg);
2157                 break;
2158         default:
2159                 arg = (compat_ulong_t)arg;
2160                 break;
2161         }
2162
2163         /*
2164          * compat_ifreq is shorter than ifreq, so we must not access beyond
2165          * the end of that structure. All fields that are used in this
2166          * driver are compatible though, we don't need to convert the
2167          * contents.
2168          */
2169         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2170 }
2171 #endif /* CONFIG_COMPAT */
2172
2173 static int tun_chr_fasync(int fd, struct file *file, int on)
2174 {
2175         struct tun_file *tfile = file->private_data;
2176         int ret;
2177
2178         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2179                 goto out;
2180
2181         if (on) {
2182                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2183                 if (ret)
2184                         goto out;
2185                 tfile->flags |= TUN_FASYNC;
2186         } else
2187                 tfile->flags &= ~TUN_FASYNC;
2188         ret = 0;
2189 out:
2190         return ret;
2191 }
2192
2193 static int tun_chr_open(struct inode *inode, struct file * file)
2194 {
2195         struct tun_file *tfile;
2196
2197         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2198
2199         tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
2200                                             &tun_proto);
2201         if (!tfile)
2202                 return -ENOMEM;
2203         rcu_assign_pointer(tfile->tun, NULL);
2204         tfile->net = get_net(current->nsproxy->net_ns);
2205         tfile->flags = 0;
2206         tfile->ifindex = 0;
2207
2208         rcu_assign_pointer(tfile->socket.wq, &tfile->wq);
2209         init_waitqueue_head(&tfile->wq.wait);
2210
2211         tfile->socket.file = file;
2212         tfile->socket.ops = &tun_socket_ops;
2213
2214         sock_init_data(&tfile->socket, &tfile->sk);
2215         sk_change_net(&tfile->sk, tfile->net);
2216
2217         tfile->sk.sk_write_space = tun_sock_write_space;
2218         tfile->sk.sk_sndbuf = INT_MAX;
2219
2220         file->private_data = tfile;
2221         set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
2222         INIT_LIST_HEAD(&tfile->next);
2223
2224         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2225
2226         return 0;
2227 }
2228
2229 static int tun_chr_close(struct inode *inode, struct file *file)
2230 {
2231         struct tun_file *tfile = file->private_data;
2232         struct net *net = tfile->net;
2233
2234         tun_detach(tfile, true);
2235         put_net(net);
2236
2237         return 0;
2238 }
2239
2240 #ifdef CONFIG_PROC_FS
2241 static int tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2242 {
2243         struct tun_struct *tun;
2244         struct ifreq ifr;
2245
2246         memset(&ifr, 0, sizeof(ifr));
2247
2248         rtnl_lock();
2249         tun = tun_get(f);
2250         if (tun)
2251                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2252         rtnl_unlock();
2253
2254         if (tun)
2255                 tun_put(tun);
2256
2257         return seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2258 }
2259 #endif
2260
2261 static const struct file_operations tun_fops = {
2262         .owner  = THIS_MODULE,
2263         .llseek = no_llseek,
2264         .read  = do_sync_read,
2265         .aio_read  = tun_chr_aio_read,
2266         .write = do_sync_write,
2267         .aio_write = tun_chr_aio_write,
2268         .poll   = tun_chr_poll,
2269         .unlocked_ioctl = tun_chr_ioctl,
2270 #ifdef CONFIG_COMPAT
2271         .compat_ioctl = tun_chr_compat_ioctl,
2272 #endif
2273         .open   = tun_chr_open,
2274         .release = tun_chr_close,
2275         .fasync = tun_chr_fasync,
2276 #ifdef CONFIG_PROC_FS
2277         .show_fdinfo = tun_chr_show_fdinfo,
2278 #endif
2279 };
2280
2281 static struct miscdevice tun_miscdev = {
2282         .minor = TUN_MINOR,
2283         .name = "tun",
2284         .nodename = "net/tun",
2285         .fops = &tun_fops,
2286 };
2287
2288 /* ethtool interface */
2289
2290 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2291 {
2292         cmd->supported          = 0;
2293         cmd->advertising        = 0;
2294         ethtool_cmd_speed_set(cmd, SPEED_10);
2295         cmd->duplex             = DUPLEX_FULL;
2296         cmd->port               = PORT_TP;
2297         cmd->phy_address        = 0;
2298         cmd->transceiver        = XCVR_INTERNAL;
2299         cmd->autoneg            = AUTONEG_DISABLE;
2300         cmd->maxtxpkt           = 0;
2301         cmd->maxrxpkt           = 0;
2302         return 0;
2303 }
2304
2305 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2306 {
2307         struct tun_struct *tun = netdev_priv(dev);
2308
2309         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2310         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2311
2312         switch (tun->flags & TUN_TYPE_MASK) {
2313         case TUN_TUN_DEV:
2314                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2315                 break;
2316         case TUN_TAP_DEV:
2317                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2318                 break;
2319         }
2320 }
2321
2322 static u32 tun_get_msglevel(struct net_device *dev)
2323 {
2324 #ifdef TUN_DEBUG
2325         struct tun_struct *tun = netdev_priv(dev);
2326         return tun->debug;
2327 #else
2328         return -EOPNOTSUPP;
2329 #endif
2330 }
2331
2332 static void tun_set_msglevel(struct net_device *dev, u32 value)
2333 {
2334 #ifdef TUN_DEBUG
2335         struct tun_struct *tun = netdev_priv(dev);
2336         tun->debug = value;
2337 #endif
2338 }
2339
2340 static const struct ethtool_ops tun_ethtool_ops = {
2341         .get_settings   = tun_get_settings,
2342         .get_drvinfo    = tun_get_drvinfo,
2343         .get_msglevel   = tun_get_msglevel,
2344         .set_msglevel   = tun_set_msglevel,
2345         .get_link       = ethtool_op_get_link,
2346         .get_ts_info    = ethtool_op_get_ts_info,
2347 };
2348
2349
2350 static int __init tun_init(void)
2351 {
2352         int ret = 0;
2353
2354         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2355         pr_info("%s\n", DRV_COPYRIGHT);
2356
2357         ret = rtnl_link_register(&tun_link_ops);
2358         if (ret) {
2359                 pr_err("Can't register link_ops\n");
2360                 goto err_linkops;
2361         }
2362
2363         ret = misc_register(&tun_miscdev);
2364         if (ret) {
2365                 pr_err("Can't register misc device %d\n", TUN_MINOR);
2366                 goto err_misc;
2367         }
2368         return  0;
2369 err_misc:
2370         rtnl_link_unregister(&tun_link_ops);
2371 err_linkops:
2372         return ret;
2373 }
2374
2375 static void tun_cleanup(void)
2376 {
2377         misc_deregister(&tun_miscdev);
2378         rtnl_link_unregister(&tun_link_ops);
2379 }
2380
2381 /* Get an underlying socket object from tun file.  Returns error unless file is
2382  * attached to a device.  The returned object works like a packet socket, it
2383  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2384  * holding a reference to the file for as long as the socket is in use. */
2385 struct socket *tun_get_socket(struct file *file)
2386 {
2387         struct tun_file *tfile;
2388         if (file->f_op != &tun_fops)
2389                 return ERR_PTR(-EINVAL);
2390         tfile = file->private_data;
2391         if (!tfile)
2392                 return ERR_PTR(-EBADFD);
2393         return &tfile->socket;
2394 }
2395 EXPORT_SYMBOL_GPL(tun_get_socket);
2396
2397 module_init(tun_init);
2398 module_exit(tun_cleanup);
2399 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2400 MODULE_AUTHOR(DRV_COPYRIGHT);
2401 MODULE_LICENSE("GPL");
2402 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2403 MODULE_ALIAS("devname:net/tun");