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/net_namespace.h>
  69 #include <net/netns/generic.h>
  70 #include <net/rtnetlink.h>
  71 #include <net/sock.h>
  72 #include <linux/seq_file.h>
  73 #include <linux/uio.h>
  74 #include <linux/skb_array.h>
  75
  76 #include <linux/uaccess.h>
  77
  78 /* Uncomment to enable debugging */
  79 /* #define TUN_DEBUG 1 */
  80
  81 #ifdef TUN_DEBUG
  82 static int debug;
  83
  84 #define tun_debug(level, tun, fmt, args...)                     \
  85 do {                                                            \
  86         if (tun->debug)                                         \
  87                 netdev_printk(level, tun->dev, fmt, ##args);    \
  88 } while (0)
  89 #define DBG1(level, fmt, args...)                               \
  90 do {                                                            \
  91         if (debug == 2)                                         \
  92                 printk(level fmt, ##args);                      \
  93 } while (0)
  94 #else
  95 #define tun_debug(level, tun, fmt, args...)                     \
  96 do {                                                            \
  97         if (0)                                                  \
  98                 netdev_printk(level, tun->dev, fmt, ##args);    \
  99 } while (0)
 100 #define DBG1(level, fmt, args...)                               \
 101 do {                                                            \
 102         if (0)                                                  \
 103                 printk(level fmt, ##args);                      \
 104 } while (0)
 105 #endif
 106
 107 /* TUN device flags */
 108
 109 /* IFF_ATTACH_QUEUE is never stored in device flags,
 110  * overload it to mean fasync when stored there.
 111  */
 112 #define TUN_FASYNC      IFF_ATTACH_QUEUE
 113 /* High bits in flags field are unused. */
 114 #define TUN_VNET_LE     0x80000000
 115 #define TUN_VNET_BE     0x40000000
 116
 117 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
 118                       IFF_MULTI_QUEUE)
 119 #define GOODCOPY_LEN 128
 120
 121 #define FLT_EXACT_COUNT 8
 122 struct tap_filter {
 123         unsigned int    count;    /* Number of addrs. Zero means disabled */
 124         u32             mask[2];  /* Mask of the hashed addrs */
 125         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 126 };
 127
 128 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
 129  * to max number of VCPUs in guest. */
 130 #define MAX_TAP_QUEUES 256
 131 #define MAX_TAP_FLOWS  4096
 132
 133 #define TUN_FLOW_EXPIRE (3 * HZ)
 134
 135 struct tun_pcpu_stats {
 136         u64 rx_packets;
 137         u64 rx_bytes;
 138         u64 tx_packets;
 139         u64 tx_bytes;
 140         struct u64_stats_sync syncp;
 141         u32 rx_dropped;
 142         u32 tx_dropped;
 143         u32 rx_frame_errors;
 144 };
 145
 146 /* A tun_file connects an open character device to a tuntap netdevice. It
 147  * also contains all socket related structures (except sock_fprog and tap_filter)
 148  * to serve as one transmit queue for tuntap device. The sock_fprog and
 149  * tap_filter were kept in tun_struct since they were used for filtering for the
 150  * netdevice not for a specific queue (at least I didn't see the requirement for
 151  * this).
 152  *
 153  * RCU usage:
 154  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
 155  * other can only be read while rcu_read_lock or rtnl_lock is held.
 156  */
 157 struct tun_file {
 158         struct sock sk;
 159         struct socket socket;
 160         struct socket_wq wq;
 161         struct tun_struct __rcu *tun;
 162         struct fasync_struct *fasync;
 163         /* only used for fasnyc */
 164         unsigned int flags;
 165         union {
 166                 u16 queue_index;
 167                 unsigned int ifindex;
 168         };
 169         struct list_head next;
 170         struct tun_struct *detached;
 171         struct skb_array tx_array;
 172 };
 173
 174 struct tun_flow_entry {
 175         struct hlist_node hash_link;
 176         struct rcu_head rcu;
 177         struct tun_struct *tun;
 178
 179         u32 rxhash;
 180         u32 rps_rxhash;
 181         int queue_index;
 182         unsigned long updated;
 183 };
 184
 185 #define TUN_NUM_FLOW_ENTRIES 1024
 186
 187 /* Since the socket were moved to tun_file, to preserve the behavior of persist
 188  * device, socket filter, sndbuf and vnet header size were restore when the
 189  * file were attached to a persist device.
 190  */
 191 struct tun_struct {
 192         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
 193         unsigned int            numqueues;
 194         unsigned int            flags;
 195         kuid_t                  owner;
 196         kgid_t                  group;
 197
 198         struct net_device       *dev;
 199         netdev_features_t       set_features;
 200 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 201                           NETIF_F_TSO6|NETIF_F_UFO)
 202
 203         int                     align;
 204         int                     vnet_hdr_sz;
 205         int                     sndbuf;
 206         struct tap_filter       txflt;
 207         struct sock_fprog       fprog;
 208         /* protected by rtnl lock */
 209         bool                    filter_attached;
 210 #ifdef TUN_DEBUG
 211         int debug;
 212 #endif
 213         spinlock_t lock;
 214         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 215         struct timer_list flow_gc_timer;
 216         unsigned long ageing_time;
 217         unsigned int numdisabled;
 218         struct list_head disabled;
 219         void *security;
 220         u32 flow_count;
 221         u32 rx_batched;
 222         struct tun_pcpu_stats __percpu *pcpu_stats;
 223 };
 224
 225 #ifdef CONFIG_TUN_VNET_CROSS_LE
 226 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 227 {
 228         return tun->flags & TUN_VNET_BE ? false :
 229                 virtio_legacy_is_little_endian();
 230 }
 231
 232 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 233 {
 234         int be = !!(tun->flags & TUN_VNET_BE);
 235
 236         if (put_user(be, argp))
 237                 return -EFAULT;
 238
 239         return 0;
 240 }
 241
 242 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 243 {
 244         int be;
 245
 246         if (get_user(be, argp))
 247                 return -EFAULT;
 248
 249         if (be)
 250                 tun->flags |= TUN_VNET_BE;
 251         else
 252                 tun->flags &= ~TUN_VNET_BE;
 253
 254         return 0;
 255 }
 256 #else
 257 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 258 {
 259         return virtio_legacy_is_little_endian();
 260 }
 261
 262 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 263 {
 264         return -EINVAL;
 265 }
 266
 267 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 268 {
 269         return -EINVAL;
 270 }
 271 #endif /* CONFIG_TUN_VNET_CROSS_LE */
 272
 273 static inline bool tun_is_little_endian(struct tun_struct *tun)
 274 {
 275         return tun->flags & TUN_VNET_LE ||
 276                 tun_legacy_is_little_endian(tun);
 277 }
 278
 279 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
 280 {
 281         return __virtio16_to_cpu(tun_is_little_endian(tun), val);
 282 }
 283
 284 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
 285 {
 286         return __cpu_to_virtio16(tun_is_little_endian(tun), val);
 287 }
 288
 289 static inline u32 tun_hashfn(u32 rxhash)
 290 {
 291         return rxhash & 0x3ff;
 292 }
 293
 294 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 295 {
 296         struct tun_flow_entry *e;
 297
 298         hlist_for_each_entry_rcu(e, head, hash_link) {
 299                 if (e->rxhash == rxhash)
 300                         return e;
 301         }
 302         return NULL;
 303 }
 304
 305 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 306                                               struct hlist_head *head,
 307                                               u32 rxhash, u16 queue_index)
 308 {
 309         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 310
 311         if (e) {
 312                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 313                           rxhash, queue_index);
 314                 e->updated = jiffies;
 315                 e->rxhash = rxhash;
 316                 e->rps_rxhash = 0;
 317                 e->queue_index = queue_index;
 318                 e->tun = tun;
 319                 hlist_add_head_rcu(&e->hash_link, head);
 320                 ++tun->flow_count;
 321         }
 322         return e;
 323 }
 324
 325 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 326 {
 327         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 328                   e->rxhash, e->queue_index);
 329         hlist_del_rcu(&e->hash_link);
 330         kfree_rcu(e, rcu);
 331         --tun->flow_count;
 332 }
 333
 334 static void tun_flow_flush(struct tun_struct *tun)
 335 {
 336         int i;
 337
 338         spin_lock_bh(&tun->lock);
 339         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 340                 struct tun_flow_entry *e;
 341                 struct hlist_node *n;
 342
 343                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 344                         tun_flow_delete(tun, e);
 345         }
 346         spin_unlock_bh(&tun->lock);
 347 }
 348
 349 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 350 {
 351         int i;
 352
 353         spin_lock_bh(&tun->lock);
 354         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 355                 struct tun_flow_entry *e;
 356                 struct hlist_node *n;
 357
 358                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 359                         if (e->queue_index == queue_index)
 360                                 tun_flow_delete(tun, e);
 361                 }
 362         }
 363         spin_unlock_bh(&tun->lock);
 364 }
 365
 366 static void tun_flow_cleanup(unsigned long data)
 367 {
 368         struct tun_struct *tun = (struct tun_struct *)data;
 369         unsigned long delay = tun->ageing_time;
 370         unsigned long next_timer = jiffies + delay;
 371         unsigned long count = 0;
 372         int i;
 373
 374         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 375
 376         spin_lock_bh(&tun->lock);
 377         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 378                 struct tun_flow_entry *e;
 379                 struct hlist_node *n;
 380
 381                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 382                         unsigned long this_timer;
 383                         count++;
 384                         this_timer = e->updated + delay;
 385                         if (time_before_eq(this_timer, jiffies))
 386                                 tun_flow_delete(tun, e);
 387                         else if (time_before(this_timer, next_timer))
 388                                 next_timer = this_timer;
 389                 }
 390         }
 391
 392         if (count)
 393                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 394         spin_unlock_bh(&tun->lock);
 395 }
 396
 397 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 398                             struct tun_file *tfile)
 399 {
 400         struct hlist_head *head;
 401         struct tun_flow_entry *e;
 402         unsigned long delay = tun->ageing_time;
 403         u16 queue_index = tfile->queue_index;
 404
 405         if (!rxhash)
 406                 return;
 407         else
 408                 head = &tun->flows[tun_hashfn(rxhash)];
 409
 410         rcu_read_lock();
 411
 412         /* We may get a very small possibility of OOO during switching, not
 413          * worth to optimize.*/
 414         if (tun->numqueues == 1 || tfile->detached)
 415                 goto unlock;
 416
 417         e = tun_flow_find(head, rxhash);
 418         if (likely(e)) {
 419                 /* TODO: keep queueing to old queue until it's empty? */
 420                 e->queue_index = queue_index;
 421                 e->updated = jiffies;
 422                 sock_rps_record_flow_hash(e->rps_rxhash);
 423         } else {
 424                 spin_lock_bh(&tun->lock);
 425                 if (!tun_flow_find(head, rxhash) &&
 426                     tun->flow_count < MAX_TAP_FLOWS)
 427                         tun_flow_create(tun, head, rxhash, queue_index);
 428
 429                 if (!timer_pending(&tun->flow_gc_timer))
 430                         mod_timer(&tun->flow_gc_timer,
 431                                   round_jiffies_up(jiffies + delay));
 432                 spin_unlock_bh(&tun->lock);
 433         }
 434
 435 unlock:
 436         rcu_read_unlock();
 437 }
 438
 439 /**
 440  * Save the hash received in the stack receive path and update the
 441  * flow_hash table accordingly.
 442  */
 443 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
 444 {
 445         if (unlikely(e->rps_rxhash != hash))
 446                 e->rps_rxhash = hash;
 447 }
 448
 449 /* We try to identify a flow through its rxhash first. The reason that
 450  * we do not check rxq no. is because some cards(e.g 82599), chooses
 451  * the rxq based on the txq where the last packet of the flow comes. As
 452  * the userspace application move between processors, we may get a
 453  * different rxq no. here. If we could not get rxhash, then we would
 454  * hope the rxq no. may help here.
 455  */
 456 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
 457                             void *accel_priv, select_queue_fallback_t fallback)
 458 {
 459         struct tun_struct *tun = netdev_priv(dev);
 460         struct tun_flow_entry *e;
 461         u32 txq = 0;
 462         u32 numqueues = 0;
 463
 464         rcu_read_lock();
 465         numqueues = ACCESS_ONCE(tun->numqueues);
 466
 467         txq = skb_get_hash(skb);
 468         if (txq) {
 469                 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 470                 if (e) {
 471                         tun_flow_save_rps_rxhash(e, txq);
 472                         txq = e->queue_index;
 473                 } else
 474                         /* use multiply and shift instead of expensive divide */
 475                         txq = ((u64)txq * numqueues) >> 32;
 476         } else if (likely(skb_rx_queue_recorded(skb))) {
 477                 txq = skb_get_rx_queue(skb);
 478                 while (unlikely(txq >= numqueues))
 479                         txq -= numqueues;
 480         }
 481
 482         rcu_read_unlock();
 483         return txq;
 484 }
 485
 486 static inline bool tun_not_capable(struct tun_struct *tun)
 487 {
 488         const struct cred *cred = current_cred();
 489         struct net *net = dev_net(tun->dev);
 490
 491         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 492                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 493                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 494 }
 495
 496 static void tun_set_real_num_queues(struct tun_struct *tun)
 497 {
 498         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 499         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 500 }
 501
 502 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 503 {
 504         tfile->detached = tun;
 505         list_add_tail(&tfile->next, &tun->disabled);
 506         ++tun->numdisabled;
 507 }
 508
 509 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 510 {
 511         struct tun_struct *tun = tfile->detached;
 512
 513         tfile->detached = NULL;
 514         list_del_init(&tfile->next);
 515         --tun->numdisabled;
 516         return tun;
 517 }
 518
 519 static void tun_queue_purge(struct tun_file *tfile)
 520 {
 521         struct sk_buff *skb;
 522
 523         while ((skb = skb_array_consume(&tfile->tx_array)) != NULL)
 524                 kfree_skb(skb);
 525
 526         skb_queue_purge(&tfile->sk.sk_write_queue);
 527         skb_queue_purge(&tfile->sk.sk_error_queue);
 528 }
 529
 530 static void __tun_detach(struct tun_file *tfile, bool clean)
 531 {
 532         struct tun_file *ntfile;
 533         struct tun_struct *tun;
 534
 535         tun = rtnl_dereference(tfile->tun);
 536
 537         if (tun && !tfile->detached) {
 538                 u16 index = tfile->queue_index;
 539                 BUG_ON(index >= tun->numqueues);
 540
 541                 rcu_assign_pointer(tun->tfiles[index],
 542                                    tun->tfiles[tun->numqueues - 1]);
 543                 ntfile = rtnl_dereference(tun->tfiles[index]);
 544                 ntfile->queue_index = index;
 545
 546                 --tun->numqueues;
 547                 if (clean) {
 548                         RCU_INIT_POINTER(tfile->tun, NULL);
 549                         sock_put(&tfile->sk);
 550                 } else
 551                         tun_disable_queue(tun, tfile);
 552
 553                 synchronize_net();
 554                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 555                 /* Drop read queue */
 556                 tun_queue_purge(tfile);
 557                 tun_set_real_num_queues(tun);
 558         } else if (tfile->detached && clean) {
 559                 tun = tun_enable_queue(tfile);
 560                 sock_put(&tfile->sk);
 561         }
 562
 563         if (clean) {
 564                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 565                         netif_carrier_off(tun->dev);
 566
 567                         if (!(tun->flags & IFF_PERSIST) &&
 568                             tun->dev->reg_state == NETREG_REGISTERED)
 569                                 unregister_netdevice(tun->dev);
 570                 }
 571                 if (tun)
 572                         skb_array_cleanup(&tfile->tx_array);
 573                 sock_put(&tfile->sk);
 574         }
 575 }
 576
 577 static void tun_detach(struct tun_file *tfile, bool clean)
 578 {
 579         rtnl_lock();
 580         __tun_detach(tfile, clean);
 581         rtnl_unlock();
 582 }
 583
 584 static void tun_detach_all(struct net_device *dev)
 585 {
 586         struct tun_struct *tun = netdev_priv(dev);
 587         struct tun_file *tfile, *tmp;
 588         int i, n = tun->numqueues;
 589
 590         for (i = 0; i < n; i++) {
 591                 tfile = rtnl_dereference(tun->tfiles[i]);
 592                 BUG_ON(!tfile);
 593                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 594                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 595                 RCU_INIT_POINTER(tfile->tun, NULL);
 596                 --tun->numqueues;
 597         }
 598         list_for_each_entry(tfile, &tun->disabled, next) {
 599                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 600                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 601                 RCU_INIT_POINTER(tfile->tun, NULL);
 602         }
 603         BUG_ON(tun->numqueues != 0);
 604
 605         synchronize_net();
 606         for (i = 0; i < n; i++) {
 607                 tfile = rtnl_dereference(tun->tfiles[i]);
 608                 /* Drop read queue */
 609                 tun_queue_purge(tfile);
 610                 sock_put(&tfile->sk);
 611         }
 612         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 613                 tun_enable_queue(tfile);
 614                 tun_queue_purge(tfile);
 615                 sock_put(&tfile->sk);
 616         }
 617         BUG_ON(tun->numdisabled != 0);
 618
 619         if (tun->flags & IFF_PERSIST)
 620                 module_put(THIS_MODULE);
 621 }
 622
 623 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
 624 {
 625         struct tun_file *tfile = file->private_data;
 626         struct net_device *dev = tun->dev;
 627         int err;
 628
 629         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 630         if (err < 0)
 631                 goto out;
 632
 633         err = -EINVAL;
 634         if (rtnl_dereference(tfile->tun) && !tfile->detached)
 635                 goto out;
 636
 637         err = -EBUSY;
 638         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
 639                 goto out;
 640
 641         err = -E2BIG;
 642         if (!tfile->detached &&
 643             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 644                 goto out;
 645
 646         err = 0;
 647
 648         /* Re-attach the filter to persist device */
 649         if (!skip_filter && (tun->filter_attached == true)) {
 650                 lock_sock(tfile->socket.sk);
 651                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 652                 release_sock(tfile->socket.sk);
 653                 if (!err)
 654                         goto out;
 655         }
 656
 657         if (!tfile->detached &&
 658             skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL)) {
 659                 err = -ENOMEM;
 660                 goto out;
 661         }
 662
 663         tfile->queue_index = tun->numqueues;
 664         tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
 665         rcu_assign_pointer(tfile->tun, tun);
 666         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 667         tun->numqueues++;
 668
 669         if (tfile->detached)
 670                 tun_enable_queue(tfile);
 671         else
 672                 sock_hold(&tfile->sk);
 673
 674         tun_set_real_num_queues(tun);
 675
 676         /* device is allowed to go away first, so no need to hold extra
 677          * refcnt.
 678          */
 679
 680 out:
 681         return err;
 682 }
 683
 684 static struct tun_struct *__tun_get(struct tun_file *tfile)
 685 {
 686         struct tun_struct *tun;
 687
 688         rcu_read_lock();
 689         tun = rcu_dereference(tfile->tun);
 690         if (tun)
 691                 dev_hold(tun->dev);
 692         rcu_read_unlock();
 693
 694         return tun;
 695 }
 696
 697 static struct tun_struct *tun_get(struct file *file)
 698 {
 699         return __tun_get(file->private_data);
 700 }
 701
 702 static void tun_put(struct tun_struct *tun)
 703 {
 704         dev_put(tun->dev);
 705 }
 706
 707 /* TAP filtering */
 708 static void addr_hash_set(u32 *mask, const u8 *addr)
 709 {
 710         int n = ether_crc(ETH_ALEN, addr) >> 26;
 711         mask[n >> 5] |= (1 << (n & 31));
 712 }
 713
 714 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 715 {
 716         int n = ether_crc(ETH_ALEN, addr) >> 26;
 717         return mask[n >> 5] & (1 << (n & 31));
 718 }
 719
 720 static int update_filter(struct tap_filter *filter, void __user *arg)
 721 {
 722         struct { u8 u[ETH_ALEN]; } *addr;
 723         struct tun_filter uf;
 724         int err, alen, n, nexact;
 725
 726         if (copy_from_user(&uf, arg, sizeof(uf)))
 727                 return -EFAULT;
 728
 729         if (!uf.count) {
 730                 /* Disabled */
 731                 filter->count = 0;
 732                 return 0;
 733         }
 734
 735         alen = ETH_ALEN * uf.count;
 736         addr = memdup_user(arg + sizeof(uf), alen);
 737         if (IS_ERR(addr))
 738                 return PTR_ERR(addr);
 739
 740         /* The filter is updated without holding any locks. Which is
 741          * perfectly safe. We disable it first and in the worst
 742          * case we'll accept a few undesired packets. */
 743         filter->count = 0;
 744         wmb();
 745
 746         /* Use first set of addresses as an exact filter */
 747         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 748                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 749
 750         nexact = n;
 751
 752         /* Remaining multicast addresses are hashed,
 753          * unicast will leave the filter disabled. */
 754         memset(filter->mask, 0, sizeof(filter->mask));
 755         for (; n < uf.count; n++) {
 756                 if (!is_multicast_ether_addr(addr[n].u)) {
 757                         err = 0; /* no filter */
 758                         goto free_addr;
 759                 }
 760                 addr_hash_set(filter->mask, addr[n].u);
 761         }
 762
 763         /* For ALLMULTI just set the mask to all ones.
 764          * This overrides the mask populated above. */
 765         if ((uf.flags & TUN_FLT_ALLMULTI))
 766                 memset(filter->mask, ~0, sizeof(filter->mask));
 767
 768         /* Now enable the filter */
 769         wmb();
 770         filter->count = nexact;
 771
 772         /* Return the number of exact filters */
 773         err = nexact;
 774 free_addr:
 775         kfree(addr);
 776         return err;
 777 }
 778
 779 /* Returns: 0 - drop, !=0 - accept */
 780 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 781 {
 782         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 783          * at this point. */
 784         struct ethhdr *eh = (struct ethhdr *) skb->data;
 785         int i;
 786
 787         /* Exact match */
 788         for (i = 0; i < filter->count; i++)
 789                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 790                         return 1;
 791
 792         /* Inexact match (multicast only) */
 793         if (is_multicast_ether_addr(eh->h_dest))
 794                 return addr_hash_test(filter->mask, eh->h_dest);
 795
 796         return 0;
 797 }
 798
 799 /*
 800  * Checks whether the packet is accepted or not.
 801  * Returns: 0 - drop, !=0 - accept
 802  */
 803 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 804 {
 805         if (!filter->count)
 806                 return 1;
 807
 808         return run_filter(filter, skb);
 809 }
 810
 811 /* Network device part of the driver */
 812
 813 static const struct ethtool_ops tun_ethtool_ops;
 814
 815 /* Net device detach from fd. */
 816 static void tun_net_uninit(struct net_device *dev)
 817 {
 818         tun_detach_all(dev);
 819 }
 820
 821 /* Net device open. */
 822 static int tun_net_open(struct net_device *dev)
 823 {
 824         netif_tx_start_all_queues(dev);
 825         return 0;
 826 }
 827
 828 /* Net device close. */
 829 static int tun_net_close(struct net_device *dev)
 830 {
 831         netif_tx_stop_all_queues(dev);
 832         return 0;
 833 }
 834
 835 /* Net device start xmit */
 836 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 837 {
 838         struct tun_struct *tun = netdev_priv(dev);
 839         int txq = skb->queue_mapping;
 840         struct tun_file *tfile;
 841         u32 numqueues = 0;
 842
 843         rcu_read_lock();
 844         tfile = rcu_dereference(tun->tfiles[txq]);
 845         numqueues = ACCESS_ONCE(tun->numqueues);
 846
 847         /* Drop packet if interface is not attached */
 848         if (txq >= numqueues)
 849                 goto drop;
 850
 851 #ifdef CONFIG_RPS
 852         if (numqueues == 1 && static_key_false(&rps_needed)) {
 853                 /* Select queue was not called for the skbuff, so we extract the
 854                  * RPS hash and save it into the flow_table here.
 855                  */
 856                 __u32 rxhash;
 857
 858                 rxhash = skb_get_hash(skb);
 859                 if (rxhash) {
 860                         struct tun_flow_entry *e;
 861                         e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
 862                                         rxhash);
 863                         if (e)
 864                                 tun_flow_save_rps_rxhash(e, rxhash);
 865                 }
 866         }
 867 #endif
 868
 869         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 870
 871         BUG_ON(!tfile);
 872
 873         /* Drop if the filter does not like it.
 874          * This is a noop if the filter is disabled.
 875          * Filter can be enabled only for the TAP devices. */
 876         if (!check_filter(&tun->txflt, skb))
 877                 goto drop;
 878
 879         if (tfile->socket.sk->sk_filter &&
 880             sk_filter(tfile->socket.sk, skb))
 881                 goto drop;
 882
 883         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 884                 goto drop;
 885
 886         skb_tx_timestamp(skb);
 887
 888         /* Orphan the skb - required as we might hang on to it
 889          * for indefinite time.
 890          */
 891         skb_orphan(skb);
 892
 893         nf_reset(skb);
 894
 895         if (skb_array_produce(&tfile->tx_array, skb))
 896                 goto drop;
 897
 898         /* Notify and wake up reader process */
 899         if (tfile->flags & TUN_FASYNC)
 900                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
 901         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 902
 903         rcu_read_unlock();
 904         return NETDEV_TX_OK;
 905
 906 drop:
 907         this_cpu_inc(tun->pcpu_stats->tx_dropped);
 908         skb_tx_error(skb);
 909         kfree_skb(skb);
 910         rcu_read_unlock();
 911         return NET_XMIT_DROP;
 912 }
 913
 914 static void tun_net_mclist(struct net_device *dev)
 915 {
 916         /*
 917          * This callback is supposed to deal with mc filter in
 918          * _rx_ path and has nothing to do with the _tx_ path.
 919          * In rx path we always accept everything userspace gives us.
 920          */
 921 }
 922
 923 static netdev_features_t tun_net_fix_features(struct net_device *dev,
 924         netdev_features_t features)
 925 {
 926         struct tun_struct *tun = netdev_priv(dev);
 927
 928         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 929 }
 930 #ifdef CONFIG_NET_POLL_CONTROLLER
 931 static void tun_poll_controller(struct net_device *dev)
 932 {
 933         /*
 934          * Tun only receives frames when:
 935          * 1) the char device endpoint gets data from user space
 936          * 2) the tun socket gets a sendmsg call from user space
 937          * Since both of those are synchronous operations, we are guaranteed
 938          * never to have pending data when we poll for it
 939          * so there is nothing to do here but return.
 940          * We need this though so netpoll recognizes us as an interface that
 941          * supports polling, which enables bridge devices in virt setups to
 942          * still use netconsole
 943          */
 944         return;
 945 }
 946 #endif
 947
 948 static void tun_set_headroom(struct net_device *dev, int new_hr)
 949 {
 950         struct tun_struct *tun = netdev_priv(dev);
 951
 952         if (new_hr < NET_SKB_PAD)
 953                 new_hr = NET_SKB_PAD;
 954
 955         tun->align = new_hr;
 956 }
 957
 958 static void
 959 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 960 {
 961         u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
 962         struct tun_struct *tun = netdev_priv(dev);
 963         struct tun_pcpu_stats *p;
 964         int i;
 965
 966         for_each_possible_cpu(i) {
 967                 u64 rxpackets, rxbytes, txpackets, txbytes;
 968                 unsigned int start;
 969
 970                 p = per_cpu_ptr(tun->pcpu_stats, i);
 971                 do {
 972                         start = u64_stats_fetch_begin(&p->syncp);
 973                         rxpackets       = p->rx_packets;
 974                         rxbytes         = p->rx_bytes;
 975                         txpackets       = p->tx_packets;
 976                         txbytes         = p->tx_bytes;
 977                 } while (u64_stats_fetch_retry(&p->syncp, start));
 978
 979                 stats->rx_packets       += rxpackets;
 980                 stats->rx_bytes         += rxbytes;
 981                 stats->tx_packets       += txpackets;
 982                 stats->tx_bytes         += txbytes;
 983
 984                 /* u32 counters */
 985                 rx_dropped      += p->rx_dropped;
 986                 rx_frame_errors += p->rx_frame_errors;
 987                 tx_dropped      += p->tx_dropped;
 988         }
 989         stats->rx_dropped  = rx_dropped;
 990         stats->rx_frame_errors = rx_frame_errors;
 991         stats->tx_dropped = tx_dropped;
 992 }
 993
 994 static const struct net_device_ops tun_netdev_ops = {
 995         .ndo_uninit             = tun_net_uninit,
 996         .ndo_open               = tun_net_open,
 997         .ndo_stop               = tun_net_close,
 998         .ndo_start_xmit         = tun_net_xmit,
 999         .ndo_fix_features       = tun_net_fix_features,
1000         .ndo_select_queue       = tun_select_queue,
1001 #ifdef CONFIG_NET_POLL_CONTROLLER
1002         .ndo_poll_controller    = tun_poll_controller,
1003 #endif
1004         .ndo_set_rx_headroom    = tun_set_headroom,
1005         .ndo_get_stats64        = tun_net_get_stats64,
1006 };
1007
1008 static const struct net_device_ops tap_netdev_ops = {
1009         .ndo_uninit             = tun_net_uninit,
1010         .ndo_open               = tun_net_open,
1011         .ndo_stop               = tun_net_close,
1012         .ndo_start_xmit         = tun_net_xmit,
1013         .ndo_fix_features       = tun_net_fix_features,
1014         .ndo_set_rx_mode        = tun_net_mclist,
1015         .ndo_set_mac_address    = eth_mac_addr,
1016         .ndo_validate_addr      = eth_validate_addr,
1017         .ndo_select_queue       = tun_select_queue,
1018 #ifdef CONFIG_NET_POLL_CONTROLLER
1019         .ndo_poll_controller    = tun_poll_controller,
1020 #endif
1021         .ndo_features_check     = passthru_features_check,
1022         .ndo_set_rx_headroom    = tun_set_headroom,
1023         .ndo_get_stats64        = tun_net_get_stats64,
1024 };
1025
1026 static void tun_flow_init(struct tun_struct *tun)
1027 {
1028         int i;
1029
1030         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1031                 INIT_HLIST_HEAD(&tun->flows[i]);
1032
1033         tun->ageing_time = TUN_FLOW_EXPIRE;
1034         setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
1035         mod_timer(&tun->flow_gc_timer,
1036                   round_jiffies_up(jiffies + tun->ageing_time));
1037 }
1038
1039 static void tun_flow_uninit(struct tun_struct *tun)
1040 {
1041         del_timer_sync(&tun->flow_gc_timer);
1042         tun_flow_flush(tun);
1043 }
1044
1045 #define MIN_MTU 68
1046 #define MAX_MTU 65535
1047
1048 /* Initialize net device. */
1049 static void tun_net_init(struct net_device *dev)
1050 {
1051         struct tun_struct *tun = netdev_priv(dev);
1052
1053         switch (tun->flags & TUN_TYPE_MASK) {
1054         case IFF_TUN:
1055                 dev->netdev_ops = &tun_netdev_ops;
1056
1057                 /* Point-to-Point TUN Device */
1058                 dev->hard_header_len = 0;
1059                 dev->addr_len = 0;
1060                 dev->mtu = 1500;
1061
1062                 /* Zero header length */
1063                 dev->type = ARPHRD_NONE;
1064                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1065                 break;
1066
1067         case IFF_TAP:
1068                 dev->netdev_ops = &tap_netdev_ops;
1069                 /* Ethernet TAP Device */
1070                 ether_setup(dev);
1071                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1072                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1073
1074                 eth_hw_addr_random(dev);
1075
1076                 break;
1077         }
1078
1079         dev->min_mtu = MIN_MTU;
1080         dev->max_mtu = MAX_MTU - dev->hard_header_len;
1081 }
1082
1083 /* Character device part */
1084
1085 /* Poll */
1086 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1087 {
1088         struct tun_file *tfile = file->private_data;
1089         struct tun_struct *tun = __tun_get(tfile);
1090         struct sock *sk;
1091         unsigned int mask = 0;
1092
1093         if (!tun)
1094                 return POLLERR;
1095
1096         sk = tfile->socket.sk;
1097
1098         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1099
1100         poll_wait(file, sk_sleep(sk), wait);
1101
1102         if (!skb_array_empty(&tfile->tx_array))
1103                 mask |= POLLIN | POLLRDNORM;
1104
1105         if (sock_writeable(sk) ||
1106             (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1107              sock_writeable(sk)))
1108                 mask |= POLLOUT | POLLWRNORM;
1109
1110         if (tun->dev->reg_state != NETREG_REGISTERED)
1111                 mask = POLLERR;
1112
1113         tun_put(tun);
1114         return mask;
1115 }
1116
1117 /* prepad is the amount to reserve at front.  len is length after that.
1118  * linear is a hint as to how much to copy (usually headers). */
1119 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1120                                      size_t prepad, size_t len,
1121                                      size_t linear, int noblock)
1122 {
1123         struct sock *sk = tfile->socket.sk;
1124         struct sk_buff *skb;
1125         int err;
1126
1127         /* Under a page?  Don't bother with paged skb. */
1128         if (prepad + len < PAGE_SIZE || !linear)
1129                 linear = len;
1130
1131         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1132                                    &err, 0);
1133         if (!skb)
1134                 return ERR_PTR(err);
1135
1136         skb_reserve(skb, prepad);
1137         skb_put(skb, linear);
1138         skb->data_len = len - linear;
1139         skb->len += len - linear;
1140
1141         return skb;
1142 }
1143
1144 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1145                            struct sk_buff *skb, int more)
1146 {
1147         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1148         struct sk_buff_head process_queue;
1149         u32 rx_batched = tun->rx_batched;
1150         bool rcv = false;
1151
1152         if (!rx_batched || (!more && skb_queue_empty(queue))) {
1153                 local_bh_disable();
1154                 netif_receive_skb(skb);
1155                 local_bh_enable();
1156                 return;
1157         }
1158
1159         spin_lock(&queue->lock);
1160         if (!more || skb_queue_len(queue) == rx_batched) {
1161                 __skb_queue_head_init(&process_queue);
1162                 skb_queue_splice_tail_init(queue, &process_queue);
1163                 rcv = true;
1164         } else {
1165                 __skb_queue_tail(queue, skb);
1166         }
1167         spin_unlock(&queue->lock);
1168
1169         if (rcv) {
1170                 struct sk_buff *nskb;
1171
1172                 local_bh_disable();
1173                 while ((nskb = __skb_dequeue(&process_queue)))
1174                         netif_receive_skb(nskb);
1175                 netif_receive_skb(skb);
1176                 local_bh_enable();
1177         }
1178 }
1179
1180 /* Get packet from user space buffer */
1181 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1182                             void *msg_control, struct iov_iter *from,
1183                             int noblock, bool more)
1184 {
1185         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1186         struct sk_buff *skb;
1187         size_t total_len = iov_iter_count(from);
1188         size_t len = total_len, align = tun->align, linear;
1189         struct virtio_net_hdr gso = { 0 };
1190         struct tun_pcpu_stats *stats;
1191         int good_linear;
1192         int copylen;
1193         bool zerocopy = false;
1194         int err;
1195         u32 rxhash;
1196
1197         if (!(tun->dev->flags & IFF_UP))
1198                 return -EIO;
1199
1200         if (!(tun->flags & IFF_NO_PI)) {
1201                 if (len < sizeof(pi))
1202                         return -EINVAL;
1203                 len -= sizeof(pi);
1204
1205                 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1206                         return -EFAULT;
1207         }
1208
1209         if (tun->flags & IFF_VNET_HDR) {
1210                 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1211
1212                 if (len < vnet_hdr_sz)
1213                         return -EINVAL;
1214                 len -= vnet_hdr_sz;
1215
1216                 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1217                         return -EFAULT;
1218
1219                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1220                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1221                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1222
1223                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1224                         return -EINVAL;
1225                 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1226         }
1227
1228         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1229                 align += NET_IP_ALIGN;
1230                 if (unlikely(len < ETH_HLEN ||
1231                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1232                         return -EINVAL;
1233         }
1234
1235         good_linear = SKB_MAX_HEAD(align);
1236
1237         if (msg_control) {
1238                 struct iov_iter i = *from;
1239
1240                 /* There are 256 bytes to be copied in skb, so there is
1241                  * enough room for skb expand head in case it is used.
1242                  * The rest of the buffer is mapped from userspace.
1243                  */
1244                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1245                 if (copylen > good_linear)
1246                         copylen = good_linear;
1247                 linear = copylen;
1248                 iov_iter_advance(&i, copylen);
1249                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1250                         zerocopy = true;
1251         }
1252
1253         if (!zerocopy) {
1254                 copylen = len;
1255                 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1256                         linear = good_linear;
1257                 else
1258                         linear = tun16_to_cpu(tun, gso.hdr_len);
1259         }
1260
1261         skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1262         if (IS_ERR(skb)) {
1263                 if (PTR_ERR(skb) != -EAGAIN)
1264                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1265                 return PTR_ERR(skb);
1266         }
1267
1268         if (zerocopy)
1269                 err = zerocopy_sg_from_iter(skb, from);
1270         else
1271                 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1272
1273         if (err) {
1274                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1275                 kfree_skb(skb);
1276                 return -EFAULT;
1277         }
1278
1279         if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1280                 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1281                 kfree_skb(skb);
1282                 return -EINVAL;
1283         }
1284
1285         switch (tun->flags & TUN_TYPE_MASK) {
1286         case IFF_TUN:
1287                 if (tun->flags & IFF_NO_PI) {
1288                         switch (skb->data[0] & 0xf0) {
1289                         case 0x40:
1290                                 pi.proto = htons(ETH_P_IP);
1291                                 break;
1292                         case 0x60:
1293                                 pi.proto = htons(ETH_P_IPV6);
1294                                 break;
1295                         default:
1296                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1297                                 kfree_skb(skb);
1298                                 return -EINVAL;
1299                         }
1300                 }
1301
1302                 skb_reset_mac_header(skb);
1303                 skb->protocol = pi.proto;
1304                 skb->dev = tun->dev;
1305                 break;
1306         case IFF_TAP:
1307                 skb->protocol = eth_type_trans(skb, tun->dev);
1308                 break;
1309         }
1310
1311         /* copy skb_ubuf_info for callback when skb has no error */
1312         if (zerocopy) {
1313                 skb_shinfo(skb)->destructor_arg = msg_control;
1314                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1315                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1316         } else if (msg_control) {
1317                 struct ubuf_info *uarg = msg_control;
1318                 uarg->callback(uarg, false);
1319         }
1320
1321         skb_reset_network_header(skb);
1322         skb_probe_transport_header(skb, 0);
1323
1324         rxhash = skb_get_hash(skb);
1325 #ifndef CONFIG_4KSTACKS
1326         tun_rx_batched(tun, tfile, skb, more);
1327 #else
1328         netif_rx_ni(skb);
1329 #endif
1330
1331         stats = get_cpu_ptr(tun->pcpu_stats);
1332         u64_stats_update_begin(&stats->syncp);
1333         stats->rx_packets++;
1334         stats->rx_bytes += len;
1335         u64_stats_update_end(&stats->syncp);
1336         put_cpu_ptr(stats);
1337
1338         tun_flow_update(tun, rxhash, tfile);
1339         return total_len;
1340 }
1341
1342 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1343 {
1344         struct file *file = iocb->ki_filp;
1345         struct tun_struct *tun = tun_get(file);
1346         struct tun_file *tfile = file->private_data;
1347         ssize_t result;
1348
1349         if (!tun)
1350                 return -EBADFD;
1351
1352         result = tun_get_user(tun, tfile, NULL, from,
1353                               file->f_flags & O_NONBLOCK, false);
1354
1355         tun_put(tun);
1356         return result;
1357 }
1358
1359 /* Put packet to the user space buffer */
1360 static ssize_t tun_put_user(struct tun_struct *tun,
1361                             struct tun_file *tfile,
1362                             struct sk_buff *skb,
1363                             struct iov_iter *iter)
1364 {
1365         struct tun_pi pi = { 0, skb->protocol };
1366         struct tun_pcpu_stats *stats;
1367         ssize_t total;
1368         int vlan_offset = 0;
1369         int vlan_hlen = 0;
1370         int vnet_hdr_sz = 0;
1371
1372         if (skb_vlan_tag_present(skb))
1373                 vlan_hlen = VLAN_HLEN;
1374
1375         if (tun->flags & IFF_VNET_HDR)
1376                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1377
1378         total = skb->len + vlan_hlen + vnet_hdr_sz;
1379
1380         if (!(tun->flags & IFF_NO_PI)) {
1381                 if (iov_iter_count(iter) < sizeof(pi))
1382                         return -EINVAL;
1383
1384                 total += sizeof(pi);
1385                 if (iov_iter_count(iter) < total) {
1386                         /* Packet will be striped */
1387                         pi.flags |= TUN_PKT_STRIP;
1388                 }
1389
1390                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1391                         return -EFAULT;
1392         }
1393
1394         if (vnet_hdr_sz) {
1395                 struct virtio_net_hdr gso;
1396
1397                 if (iov_iter_count(iter) < vnet_hdr_sz)
1398                         return -EINVAL;
1399
1400                 if (virtio_net_hdr_from_skb(skb, &gso,
1401                                             tun_is_little_endian(tun), true)) {
1402                         struct skb_shared_info *sinfo = skb_shinfo(skb);
1403                         pr_err("unexpected GSO type: "
1404                                "0x%x, gso_size %d, hdr_len %d\n",
1405                                sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1406                                tun16_to_cpu(tun, gso.hdr_len));
1407                         print_hex_dump(KERN_ERR, "tun: ",
1408                                        DUMP_PREFIX_NONE,
1409                                        16, 1, skb->head,
1410                                        min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1411                         WARN_ON_ONCE(1);
1412                         return -EINVAL;
1413                 }
1414
1415                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1416                         return -EFAULT;
1417
1418                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1419         }
1420
1421         if (vlan_hlen) {
1422                 int ret;
1423                 struct {
1424                         __be16 h_vlan_proto;
1425                         __be16 h_vlan_TCI;
1426                 } veth;
1427
1428                 veth.h_vlan_proto = skb->vlan_proto;
1429                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1430
1431                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1432
1433                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1434                 if (ret || !iov_iter_count(iter))
1435                         goto done;
1436
1437                 ret = copy_to_iter(&veth, sizeof(veth), iter);
1438                 if (ret != sizeof(veth) || !iov_iter_count(iter))
1439                         goto done;
1440         }
1441
1442         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1443
1444 done:
1445         /* caller is in process context, */
1446         stats = get_cpu_ptr(tun->pcpu_stats);
1447         u64_stats_update_begin(&stats->syncp);
1448         stats->tx_packets++;
1449         stats->tx_bytes += skb->len + vlan_hlen;
1450         u64_stats_update_end(&stats->syncp);
1451         put_cpu_ptr(tun->pcpu_stats);
1452
1453         return total;
1454 }
1455
1456 static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
1457                                      int *err)
1458 {
1459         DECLARE_WAITQUEUE(wait, current);
1460         struct sk_buff *skb = NULL;
1461         int error = 0;
1462
1463         skb = skb_array_consume(&tfile->tx_array);
1464         if (skb)
1465                 goto out;
1466         if (noblock) {
1467                 error = -EAGAIN;
1468                 goto out;
1469         }
1470
1471         add_wait_queue(&tfile->wq.wait, &wait);
1472         current->state = TASK_INTERRUPTIBLE;
1473
1474         while (1) {
1475                 skb = skb_array_consume(&tfile->tx_array);
1476                 if (skb)
1477                         break;
1478                 if (signal_pending(current)) {
1479                         error = -ERESTARTSYS;
1480                         break;
1481                 }
1482                 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
1483                         error = -EFAULT;
1484                         break;
1485                 }
1486
1487                 schedule();
1488         }
1489
1490         current->state = TASK_RUNNING;
1491         remove_wait_queue(&tfile->wq.wait, &wait);
1492
1493 out:
1494         *err = error;
1495         return skb;
1496 }
1497
1498 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1499                            struct iov_iter *to,
1500                            int noblock)
1501 {
1502         struct sk_buff *skb;
1503         ssize_t ret;
1504         int err;
1505
1506         tun_debug(KERN_INFO, tun, "tun_do_read\n");
1507
1508         if (!iov_iter_count(to))
1509                 return 0;
1510
1511         /* Read frames from ring */
1512         skb = tun_ring_recv(tfile, noblock, &err);
1513         if (!skb)
1514                 return err;
1515
1516         ret = tun_put_user(tun, tfile, skb, to);
1517         if (unlikely(ret < 0))
1518                 kfree_skb(skb);
1519         else
1520                 consume_skb(skb);
1521
1522         return ret;
1523 }
1524
1525 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1526 {
1527         struct file *file = iocb->ki_filp;
1528         struct tun_file *tfile = file->private_data;
1529         struct tun_struct *tun = __tun_get(tfile);
1530         ssize_t len = iov_iter_count(to), ret;
1531
1532         if (!tun)
1533                 return -EBADFD;
1534         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
1535         ret = min_t(ssize_t, ret, len);
1536         if (ret > 0)
1537                 iocb->ki_pos = ret;
1538         tun_put(tun);
1539         return ret;
1540 }
1541
1542 static void tun_free_netdev(struct net_device *dev)
1543 {
1544         struct tun_struct *tun = netdev_priv(dev);
1545
1546         BUG_ON(!(list_empty(&tun->disabled)));
1547         free_percpu(tun->pcpu_stats);
1548         tun_flow_uninit(tun);
1549         security_tun_dev_free_security(tun->security);
1550         free_netdev(dev);
1551 }
1552
1553 static void tun_setup(struct net_device *dev)
1554 {
1555         struct tun_struct *tun = netdev_priv(dev);
1556
1557         tun->owner = INVALID_UID;
1558         tun->group = INVALID_GID;
1559
1560         dev->ethtool_ops = &tun_ethtool_ops;
1561         dev->destructor = tun_free_netdev;
1562         /* We prefer our own queue length */
1563         dev->tx_queue_len = TUN_READQ_SIZE;
1564 }
1565
1566 /* Trivial set of netlink ops to allow deleting tun or tap
1567  * device with netlink.
1568  */
1569 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1570 {
1571         return -EINVAL;
1572 }
1573
1574 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1575         .kind           = DRV_NAME,
1576         .priv_size      = sizeof(struct tun_struct),
1577         .setup          = tun_setup,
1578         .validate       = tun_validate,
1579 };
1580
1581 static void tun_sock_write_space(struct sock *sk)
1582 {
1583         struct tun_file *tfile;
1584         wait_queue_head_t *wqueue;
1585
1586         if (!sock_writeable(sk))
1587                 return;
1588
1589         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
1590                 return;
1591
1592         wqueue = sk_sleep(sk);
1593         if (wqueue && waitqueue_active(wqueue))
1594                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1595                                                 POLLWRNORM | POLLWRBAND);
1596
1597         tfile = container_of(sk, struct tun_file, sk);
1598         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1599 }
1600
1601 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1602 {
1603         int ret;
1604         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1605         struct tun_struct *tun = __tun_get(tfile);
1606
1607         if (!tun)
1608                 return -EBADFD;
1609
1610         ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1611                            m->msg_flags & MSG_DONTWAIT,
1612                            m->msg_flags & MSG_MORE);
1613         tun_put(tun);
1614         return ret;
1615 }
1616
1617 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1618                        int flags)
1619 {
1620         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1621         struct tun_struct *tun = __tun_get(tfile);
1622         int ret;
1623
1624         if (!tun)
1625                 return -EBADFD;
1626
1627         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1628                 ret = -EINVAL;
1629                 goto out;
1630         }
1631         if (flags & MSG_ERRQUEUE) {
1632                 ret = sock_recv_errqueue(sock->sk, m, total_len,
1633                                          SOL_PACKET, TUN_TX_TIMESTAMP);
1634                 goto out;
1635         }
1636         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1637         if (ret > (ssize_t)total_len) {
1638                 m->msg_flags |= MSG_TRUNC;
1639                 ret = flags & MSG_TRUNC ? ret : total_len;
1640         }
1641 out:
1642         tun_put(tun);
1643         return ret;
1644 }
1645
1646 static int tun_peek_len(struct socket *sock)
1647 {
1648         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1649         struct tun_struct *tun;
1650         int ret = 0;
1651
1652         tun = __tun_get(tfile);
1653         if (!tun)
1654                 return 0;
1655
1656         ret = skb_array_peek_len(&tfile->tx_array);
1657         tun_put(tun);
1658
1659         return ret;
1660 }
1661
1662 /* Ops structure to mimic raw sockets with tun */
1663 static const struct proto_ops tun_socket_ops = {
1664         .peek_len = tun_peek_len,
1665         .sendmsg = tun_sendmsg,
1666         .recvmsg = tun_recvmsg,
1667 };
1668
1669 static struct proto tun_proto = {
1670         .name           = "tun",
1671         .owner          = THIS_MODULE,
1672         .obj_size       = sizeof(struct tun_file),
1673 };
1674
1675 static int tun_flags(struct tun_struct *tun)
1676 {
1677         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1678 }
1679
1680 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1681                               char *buf)
1682 {
1683         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1684         return sprintf(buf, "0x%x\n", tun_flags(tun));
1685 }
1686
1687 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1688                               char *buf)
1689 {
1690         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1691         return uid_valid(tun->owner)?
1692                 sprintf(buf, "%u\n",
1693                         from_kuid_munged(current_user_ns(), tun->owner)):
1694                 sprintf(buf, "-1\n");
1695 }
1696
1697 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1698                               char *buf)
1699 {
1700         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1701         return gid_valid(tun->group) ?
1702                 sprintf(buf, "%u\n",
1703                         from_kgid_munged(current_user_ns(), tun->group)):
1704                 sprintf(buf, "-1\n");
1705 }
1706
1707 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1708 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1709 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1710
1711 static struct attribute *tun_dev_attrs[] = {
1712         &dev_attr_tun_flags.attr,
1713         &dev_attr_owner.attr,
1714         &dev_attr_group.attr,
1715         NULL
1716 };
1717
1718 static const struct attribute_group tun_attr_group = {
1719         .attrs = tun_dev_attrs
1720 };
1721
1722 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1723 {
1724         struct tun_struct *tun;
1725         struct tun_file *tfile = file->private_data;
1726         struct net_device *dev;
1727         int err;
1728
1729         if (tfile->detached)
1730                 return -EINVAL;
1731
1732         dev = __dev_get_by_name(net, ifr->ifr_name);
1733         if (dev) {
1734                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1735                         return -EBUSY;
1736                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1737                         tun = netdev_priv(dev);
1738                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1739                         tun = netdev_priv(dev);
1740                 else
1741                         return -EINVAL;
1742
1743                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1744                     !!(tun->flags & IFF_MULTI_QUEUE))
1745                         return -EINVAL;
1746
1747                 if (tun_not_capable(tun))
1748                         return -EPERM;
1749                 err = security_tun_dev_open(tun->security);
1750                 if (err < 0)
1751                         return err;
1752
1753                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1754                 if (err < 0)
1755                         return err;
1756
1757                 if (tun->flags & IFF_MULTI_QUEUE &&
1758                     (tun->numqueues + tun->numdisabled > 1)) {
1759                         /* One or more queue has already been attached, no need
1760                          * to initialize the device again.
1761                          */
1762                         return 0;
1763                 }
1764         }
1765         else {
1766                 char *name;
1767                 unsigned long flags = 0;
1768                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1769                              MAX_TAP_QUEUES : 1;
1770
1771                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1772                         return -EPERM;
1773                 err = security_tun_dev_create();
1774                 if (err < 0)
1775                         return err;
1776
1777                 /* Set dev type */
1778                 if (ifr->ifr_flags & IFF_TUN) {
1779                         /* TUN device */
1780                         flags |= IFF_TUN;
1781                         name = "tun%d";
1782                 } else if (ifr->ifr_flags & IFF_TAP) {
1783                         /* TAP device */
1784                         flags |= IFF_TAP;
1785                         name = "tap%d";
1786                 } else
1787                         return -EINVAL;
1788
1789                 if (*ifr->ifr_name)
1790                         name = ifr->ifr_name;
1791
1792                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1793                                        NET_NAME_UNKNOWN, tun_setup, queues,
1794                                        queues);
1795
1796                 if (!dev)
1797                         return -ENOMEM;
1798
1799                 dev_net_set(dev, net);
1800                 dev->rtnl_link_ops = &tun_link_ops;
1801                 dev->ifindex = tfile->ifindex;
1802                 dev->sysfs_groups[0] = &tun_attr_group;
1803
1804                 tun = netdev_priv(dev);
1805                 tun->dev = dev;
1806                 tun->flags = flags;
1807                 tun->txflt.count = 0;
1808                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1809
1810                 tun->align = NET_SKB_PAD;
1811                 tun->filter_attached = false;
1812                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1813                 tun->rx_batched = 0;
1814
1815                 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
1816                 if (!tun->pcpu_stats) {
1817                         err = -ENOMEM;
1818                         goto err_free_dev;
1819                 }
1820
1821                 spin_lock_init(&tun->lock);
1822
1823                 err = security_tun_dev_alloc_security(&tun->security);
1824                 if (err < 0)
1825                         goto err_free_stat;
1826
1827                 tun_net_init(dev);
1828                 tun_flow_init(tun);
1829
1830                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1831                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1832                                    NETIF_F_HW_VLAN_STAG_TX;
1833                 dev->features = dev->hw_features | NETIF_F_LLTX;
1834                 dev->vlan_features = dev->features &
1835                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
1836                                        NETIF_F_HW_VLAN_STAG_TX);
1837
1838                 INIT_LIST_HEAD(&tun->disabled);
1839                 err = tun_attach(tun, file, false);
1840                 if (err < 0)
1841                         goto err_free_flow;
1842
1843                 err = register_netdevice(tun->dev);
1844                 if (err < 0)
1845                         goto err_detach;
1846         }
1847
1848         netif_carrier_on(tun->dev);
1849
1850         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1851
1852         tun->flags = (tun->flags & ~TUN_FEATURES) |
1853                 (ifr->ifr_flags & TUN_FEATURES);
1854
1855         /* Make sure persistent devices do not get stuck in
1856          * xoff state.
1857          */
1858         if (netif_running(tun->dev))
1859                 netif_tx_wake_all_queues(tun->dev);
1860
1861         strcpy(ifr->ifr_name, tun->dev->name);
1862         return 0;
1863
1864 err_detach:
1865         tun_detach_all(dev);
1866 err_free_flow:
1867         tun_flow_uninit(tun);
1868         security_tun_dev_free_security(tun->security);
1869 err_free_stat:
1870         free_percpu(tun->pcpu_stats);
1871 err_free_dev:
1872         free_netdev(dev);
1873         return err;
1874 }
1875
1876 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1877                        struct ifreq *ifr)
1878 {
1879         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1880
1881         strcpy(ifr->ifr_name, tun->dev->name);
1882
1883         ifr->ifr_flags = tun_flags(tun);
1884
1885 }
1886
1887 /* This is like a cut-down ethtool ops, except done via tun fd so no
1888  * privs required. */
1889 static int set_offload(struct tun_struct *tun, unsigned long arg)
1890 {
1891         netdev_features_t features = 0;
1892
1893         if (arg & TUN_F_CSUM) {
1894                 features |= NETIF_F_HW_CSUM;
1895                 arg &= ~TUN_F_CSUM;
1896
1897                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1898                         if (arg & TUN_F_TSO_ECN) {
1899                                 features |= NETIF_F_TSO_ECN;
1900                                 arg &= ~TUN_F_TSO_ECN;
1901                         }
1902                         if (arg & TUN_F_TSO4)
1903                                 features |= NETIF_F_TSO;
1904                         if (arg & TUN_F_TSO6)
1905                                 features |= NETIF_F_TSO6;
1906                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1907                 }
1908
1909                 if (arg & TUN_F_UFO) {
1910                         features |= NETIF_F_UFO;
1911                         arg &= ~TUN_F_UFO;
1912                 }
1913         }
1914
1915         /* This gives the user a way to test for new features in future by
1916          * trying to set them. */
1917         if (arg)
1918                 return -EINVAL;
1919
1920         tun->set_features = features;
1921         netdev_update_features(tun->dev);
1922
1923         return 0;
1924 }
1925
1926 static void tun_detach_filter(struct tun_struct *tun, int n)
1927 {
1928         int i;
1929         struct tun_file *tfile;
1930
1931         for (i = 0; i < n; i++) {
1932                 tfile = rtnl_dereference(tun->tfiles[i]);
1933                 lock_sock(tfile->socket.sk);
1934                 sk_detach_filter(tfile->socket.sk);
1935                 release_sock(tfile->socket.sk);
1936         }
1937
1938         tun->filter_attached = false;
1939 }
1940
1941 static int tun_attach_filter(struct tun_struct *tun)
1942 {
1943         int i, ret = 0;
1944         struct tun_file *tfile;
1945
1946         for (i = 0; i < tun->numqueues; i++) {
1947                 tfile = rtnl_dereference(tun->tfiles[i]);
1948                 lock_sock(tfile->socket.sk);
1949                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1950                 release_sock(tfile->socket.sk);
1951                 if (ret) {
1952                         tun_detach_filter(tun, i);
1953                         return ret;
1954                 }
1955         }
1956
1957         tun->filter_attached = true;
1958         return ret;
1959 }
1960
1961 static void tun_set_sndbuf(struct tun_struct *tun)
1962 {
1963         struct tun_file *tfile;
1964         int i;
1965
1966         for (i = 0; i < tun->numqueues; i++) {
1967                 tfile = rtnl_dereference(tun->tfiles[i]);
1968                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1969         }
1970 }
1971
1972 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1973 {
1974         struct tun_file *tfile = file->private_data;
1975         struct tun_struct *tun;
1976         int ret = 0;
1977
1978         rtnl_lock();
1979
1980         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1981                 tun = tfile->detached;
1982                 if (!tun) {
1983                         ret = -EINVAL;
1984                         goto unlock;
1985                 }
1986                 ret = security_tun_dev_attach_queue(tun->security);
1987                 if (ret < 0)
1988                         goto unlock;
1989                 ret = tun_attach(tun, file, false);
1990         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1991                 tun = rtnl_dereference(tfile->tun);
1992                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1993                         ret = -EINVAL;
1994                 else
1995                         __tun_detach(tfile, false);
1996         } else
1997                 ret = -EINVAL;
1998
1999 unlock:
2000         rtnl_unlock();
2001         return ret;
2002 }
2003
2004 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2005                             unsigned long arg, int ifreq_len)
2006 {
2007         struct tun_file *tfile = file->private_data;
2008         struct tun_struct *tun;
2009         void __user* argp = (void __user*)arg;
2010         struct ifreq ifr;
2011         kuid_t owner;
2012         kgid_t group;
2013         int sndbuf;
2014         int vnet_hdr_sz;
2015         unsigned int ifindex;
2016         int le;
2017         int ret;
2018
2019         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) {
2020                 if (copy_from_user(&ifr, argp, ifreq_len))
2021                         return -EFAULT;
2022         } else {
2023                 memset(&ifr, 0, sizeof(ifr));
2024         }
2025         if (cmd == TUNGETFEATURES) {
2026                 /* Currently this just means: "what IFF flags are valid?".
2027                  * This is needed because we never checked for invalid flags on
2028                  * TUNSETIFF.
2029                  */
2030                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2031                                 (unsigned int __user*)argp);
2032         } else if (cmd == TUNSETQUEUE)
2033                 return tun_set_queue(file, &ifr);
2034
2035         ret = 0;
2036         rtnl_lock();
2037
2038         tun = __tun_get(tfile);
2039         if (cmd == TUNSETIFF) {
2040                 ret = -EEXIST;
2041                 if (tun)
2042                         goto unlock;
2043
2044                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2045
2046                 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
2047
2048                 if (ret)
2049                         goto unlock;
2050
2051                 if (copy_to_user(argp, &ifr, ifreq_len))
2052                         ret = -EFAULT;
2053                 goto unlock;
2054         }
2055         if (cmd == TUNSETIFINDEX) {
2056                 ret = -EPERM;
2057                 if (tun)
2058                         goto unlock;
2059
2060                 ret = -EFAULT;
2061                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2062                         goto unlock;
2063
2064                 ret = 0;
2065                 tfile->ifindex = ifindex;
2066                 goto unlock;
2067         }
2068
2069         ret = -EBADFD;
2070         if (!tun)
2071                 goto unlock;
2072
2073         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2074
2075         ret = 0;
2076         switch (cmd) {
2077         case TUNGETIFF:
2078                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2079
2080                 if (tfile->detached)
2081                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
2082                 if (!tfile->socket.sk->sk_filter)
2083                         ifr.ifr_flags |= IFF_NOFILTER;
2084
2085                 if (copy_to_user(argp, &ifr, ifreq_len))
2086                         ret = -EFAULT;
2087                 break;
2088
2089         case TUNSETNOCSUM:
2090                 /* Disable/Enable checksum */
2091
2092                 /* [unimplemented] */
2093                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2094                           arg ? "disabled" : "enabled");
2095                 break;
2096
2097         case TUNSETPERSIST:
2098                 /* Disable/Enable persist mode. Keep an extra reference to the
2099                  * module to prevent the module being unprobed.
2100                  */
2101                 if (arg && !(tun->flags & IFF_PERSIST)) {
2102                         tun->flags |= IFF_PERSIST;
2103                         __module_get(THIS_MODULE);
2104                 }
2105                 if (!arg && (tun->flags & IFF_PERSIST)) {
2106                         tun->flags &= ~IFF_PERSIST;
2107                         module_put(THIS_MODULE);
2108                 }
2109
2110                 tun_debug(KERN_INFO, tun, "persist %s\n",
2111                           arg ? "enabled" : "disabled");
2112                 break;
2113
2114         case TUNSETOWNER:
2115                 /* Set owner of the device */
2116                 owner = make_kuid(current_user_ns(), arg);
2117                 if (!uid_valid(owner)) {
2118                         ret = -EINVAL;
2119                         break;
2120                 }
2121                 tun->owner = owner;
2122                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2123                           from_kuid(&init_user_ns, tun->owner));
2124                 break;
2125
2126         case TUNSETGROUP:
2127                 /* Set group of the device */
2128                 group = make_kgid(current_user_ns(), arg);
2129                 if (!gid_valid(group)) {
2130                         ret = -EINVAL;
2131                         break;
2132                 }
2133                 tun->group = group;
2134                 tun_debug(KERN_INFO, tun, "group set to %u\n",
2135                           from_kgid(&init_user_ns, tun->group));
2136                 break;
2137
2138         case TUNSETLINK:
2139                 /* Only allow setting the type when the interface is down */
2140                 if (tun->dev->flags & IFF_UP) {
2141                         tun_debug(KERN_INFO, tun,
2142                                   "Linktype set failed because interface is up\n");
2143                         ret = -EBUSY;
2144                 } else {
2145                         tun->dev->type = (int) arg;
2146                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2147                                   tun->dev->type);
2148                         ret = 0;
2149                 }
2150                 break;
2151
2152 #ifdef TUN_DEBUG
2153         case TUNSETDEBUG:
2154                 tun->debug = arg;
2155                 break;
2156 #endif
2157         case TUNSETOFFLOAD:
2158                 ret = set_offload(tun, arg);
2159                 break;
2160
2161         case TUNSETTXFILTER:
2162                 /* Can be set only for TAPs */
2163                 ret = -EINVAL;
2164                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2165                         break;
2166                 ret = update_filter(&tun->txflt, (void __user *)arg);
2167                 break;
2168
2169         case SIOCGIFHWADDR:
2170                 /* Get hw address */
2171                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2172                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2173                 if (copy_to_user(argp, &ifr, ifreq_len))
2174                         ret = -EFAULT;
2175                 break;
2176
2177         case SIOCSIFHWADDR:
2178                 /* Set hw address */
2179                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2180                           ifr.ifr_hwaddr.sa_data);
2181
2182                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2183                 break;
2184
2185         case TUNGETSNDBUF:
2186                 sndbuf = tfile->socket.sk->sk_sndbuf;
2187                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2188                         ret = -EFAULT;
2189                 break;
2190
2191         case TUNSETSNDBUF:
2192                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2193                         ret = -EFAULT;
2194                         break;
2195                 }
2196
2197                 tun->sndbuf = sndbuf;
2198                 tun_set_sndbuf(tun);
2199                 break;
2200
2201         case TUNGETVNETHDRSZ:
2202                 vnet_hdr_sz = tun->vnet_hdr_sz;
2203                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2204                         ret = -EFAULT;
2205                 break;
2206
2207         case TUNSETVNETHDRSZ:
2208                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2209                         ret = -EFAULT;
2210                         break;
2211                 }
2212                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2213                         ret = -EINVAL;
2214                         break;
2215                 }
2216
2217                 tun->vnet_hdr_sz = vnet_hdr_sz;
2218                 break;
2219
2220         case TUNGETVNETLE:
2221                 le = !!(tun->flags & TUN_VNET_LE);
2222                 if (put_user(le, (int __user *)argp))
2223                         ret = -EFAULT;
2224                 break;
2225
2226         case TUNSETVNETLE:
2227                 if (get_user(le, (int __user *)argp)) {
2228                         ret = -EFAULT;
2229                         break;
2230                 }
2231                 if (le)
2232                         tun->flags |= TUN_VNET_LE;
2233                 else
2234                         tun->flags &= ~TUN_VNET_LE;
2235                 break;
2236
2237         case TUNGETVNETBE:
2238                 ret = tun_get_vnet_be(tun, argp);
2239                 break;
2240
2241         case TUNSETVNETBE:
2242                 ret = tun_set_vnet_be(tun, argp);
2243                 break;
2244
2245         case TUNATTACHFILTER:
2246                 /* Can be set only for TAPs */
2247                 ret = -EINVAL;
2248                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2249                         break;
2250                 ret = -EFAULT;
2251                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2252                         break;
2253
2254                 ret = tun_attach_filter(tun);
2255                 break;
2256
2257         case TUNDETACHFILTER:
2258                 /* Can be set only for TAPs */
2259                 ret = -EINVAL;
2260                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2261                         break;
2262                 ret = 0;
2263                 tun_detach_filter(tun, tun->numqueues);
2264                 break;
2265
2266         case TUNGETFILTER:
2267                 ret = -EINVAL;
2268                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2269                         break;
2270                 ret = -EFAULT;
2271                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2272                         break;
2273                 ret = 0;
2274                 break;
2275
2276         default:
2277                 ret = -EINVAL;
2278                 break;
2279         }
2280
2281 unlock:
2282         rtnl_unlock();
2283         if (tun)
2284                 tun_put(tun);
2285         return ret;
2286 }
2287
2288 static long tun_chr_ioctl(struct file *file,
2289                           unsigned int cmd, unsigned long arg)
2290 {
2291         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2292 }
2293
2294 #ifdef CONFIG_COMPAT
2295 static long tun_chr_compat_ioctl(struct file *file,
2296                          unsigned int cmd, unsigned long arg)
2297 {
2298         switch (cmd) {
2299         case TUNSETIFF:
2300         case TUNGETIFF:
2301         case TUNSETTXFILTER:
2302         case TUNGETSNDBUF:
2303         case TUNSETSNDBUF:
2304         case SIOCGIFHWADDR:
2305         case SIOCSIFHWADDR:
2306                 arg = (unsigned long)compat_ptr(arg);
2307                 break;
2308         default:
2309                 arg = (compat_ulong_t)arg;
2310                 break;
2311         }
2312
2313         /*
2314          * compat_ifreq is shorter than ifreq, so we must not access beyond
2315          * the end of that structure. All fields that are used in this
2316          * driver are compatible though, we don't need to convert the
2317          * contents.
2318          */
2319         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2320 }
2321 #endif /* CONFIG_COMPAT */
2322
2323 static int tun_chr_fasync(int fd, struct file *file, int on)
2324 {
2325         struct tun_file *tfile = file->private_data;
2326         int ret;
2327
2328         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2329                 goto out;
2330
2331         if (on) {
2332                 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2333                 tfile->flags |= TUN_FASYNC;
2334         } else
2335                 tfile->flags &= ~TUN_FASYNC;
2336         ret = 0;
2337 out:
2338         return ret;
2339 }
2340
2341 static int tun_chr_open(struct inode *inode, struct file * file)
2342 {
2343         struct net *net = current->nsproxy->net_ns;
2344         struct tun_file *tfile;
2345
2346         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2347
2348         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2349                                             &tun_proto, 0);
2350         if (!tfile)
2351                 return -ENOMEM;
2352         RCU_INIT_POINTER(tfile->tun, NULL);
2353         tfile->flags = 0;
2354         tfile->ifindex = 0;
2355
2356         init_waitqueue_head(&tfile->wq.wait);
2357         RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2358
2359         tfile->socket.file = file;
2360         tfile->socket.ops = &tun_socket_ops;
2361
2362         sock_init_data(&tfile->socket, &tfile->sk);
2363
2364         tfile->sk.sk_write_space = tun_sock_write_space;
2365         tfile->sk.sk_sndbuf = INT_MAX;
2366
2367         file->private_data = tfile;
2368         INIT_LIST_HEAD(&tfile->next);
2369
2370         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2371
2372         return 0;
2373 }
2374
2375 static int tun_chr_close(struct inode *inode, struct file *file)
2376 {
2377         struct tun_file *tfile = file->private_data;
2378
2379         tun_detach(tfile, true);
2380
2381         return 0;
2382 }
2383
2384 #ifdef CONFIG_PROC_FS
2385 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2386 {
2387         struct tun_struct *tun;
2388         struct ifreq ifr;
2389
2390         memset(&ifr, 0, sizeof(ifr));
2391
2392         rtnl_lock();
2393         tun = tun_get(f);
2394         if (tun)
2395                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2396         rtnl_unlock();
2397
2398         if (tun)
2399                 tun_put(tun);
2400
2401         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2402 }
2403 #endif
2404
2405 static const struct file_operations tun_fops = {
2406         .owner  = THIS_MODULE,
2407         .llseek = no_llseek,
2408         .read_iter  = tun_chr_read_iter,
2409         .write_iter = tun_chr_write_iter,
2410         .poll   = tun_chr_poll,
2411         .unlocked_ioctl = tun_chr_ioctl,
2412 #ifdef CONFIG_COMPAT
2413         .compat_ioctl = tun_chr_compat_ioctl,
2414 #endif
2415         .open   = tun_chr_open,
2416         .release = tun_chr_close,
2417         .fasync = tun_chr_fasync,
2418 #ifdef CONFIG_PROC_FS
2419         .show_fdinfo = tun_chr_show_fdinfo,
2420 #endif
2421 };
2422
2423 static struct miscdevice tun_miscdev = {
2424         .minor = TUN_MINOR,
2425         .name = "tun",
2426         .nodename = "net/tun",
2427         .fops = &tun_fops,
2428 };
2429
2430 /* ethtool interface */
2431
2432 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2433 {
2434         cmd->supported          = 0;
2435         cmd->advertising        = 0;
2436         ethtool_cmd_speed_set(cmd, SPEED_10);
2437         cmd->duplex             = DUPLEX_FULL;
2438         cmd->port               = PORT_TP;
2439         cmd->phy_address        = 0;
2440         cmd->transceiver        = XCVR_INTERNAL;
2441         cmd->autoneg            = AUTONEG_DISABLE;
2442         cmd->maxtxpkt           = 0;
2443         cmd->maxrxpkt           = 0;
2444         return 0;
2445 }
2446
2447 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2448 {
2449         struct tun_struct *tun = netdev_priv(dev);
2450
2451         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2452         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2453
2454         switch (tun->flags & TUN_TYPE_MASK) {
2455         case IFF_TUN:
2456                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2457                 break;
2458         case IFF_TAP:
2459                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2460                 break;
2461         }
2462 }
2463
2464 static u32 tun_get_msglevel(struct net_device *dev)
2465 {
2466 #ifdef TUN_DEBUG
2467         struct tun_struct *tun = netdev_priv(dev);
2468         return tun->debug;
2469 #else
2470         return -EOPNOTSUPP;
2471 #endif
2472 }
2473
2474 static void tun_set_msglevel(struct net_device *dev, u32 value)
2475 {
2476 #ifdef TUN_DEBUG
2477         struct tun_struct *tun = netdev_priv(dev);
2478         tun->debug = value;
2479 #endif
2480 }
2481
2482 static int tun_get_coalesce(struct net_device *dev,
2483                             struct ethtool_coalesce *ec)
2484 {
2485         struct tun_struct *tun = netdev_priv(dev);
2486
2487         ec->rx_max_coalesced_frames = tun->rx_batched;
2488
2489         return 0;
2490 }
2491
2492 static int tun_set_coalesce(struct net_device *dev,
2493                             struct ethtool_coalesce *ec)
2494 {
2495         struct tun_struct *tun = netdev_priv(dev);
2496
2497         if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
2498                 tun->rx_batched = NAPI_POLL_WEIGHT;
2499         else
2500                 tun->rx_batched = ec->rx_max_coalesced_frames;
2501
2502         return 0;
2503 }
2504
2505 static const struct ethtool_ops tun_ethtool_ops = {
2506         .get_settings   = tun_get_settings,
2507         .get_drvinfo    = tun_get_drvinfo,
2508         .get_msglevel   = tun_get_msglevel,
2509         .set_msglevel   = tun_set_msglevel,
2510         .get_link       = ethtool_op_get_link,
2511         .get_ts_info    = ethtool_op_get_ts_info,
2512         .get_coalesce   = tun_get_coalesce,
2513         .set_coalesce   = tun_set_coalesce,
2514 };
2515
2516 static int tun_queue_resize(struct tun_struct *tun)
2517 {
2518         struct net_device *dev = tun->dev;
2519         struct tun_file *tfile;
2520         struct skb_array **arrays;
2521         int n = tun->numqueues + tun->numdisabled;
2522         int ret, i;
2523
2524         arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL);
2525         if (!arrays)
2526                 return -ENOMEM;
2527
2528         for (i = 0; i < tun->numqueues; i++) {
2529                 tfile = rtnl_dereference(tun->tfiles[i]);
2530                 arrays[i] = &tfile->tx_array;
2531         }
2532         list_for_each_entry(tfile, &tun->disabled, next)
2533                 arrays[i++] = &tfile->tx_array;
2534
2535         ret = skb_array_resize_multiple(arrays, n,
2536                                         dev->tx_queue_len, GFP_KERNEL);
2537
2538         kfree(arrays);
2539         return ret;
2540 }
2541
2542 static int tun_device_event(struct notifier_block *unused,
2543                             unsigned long event, void *ptr)
2544 {
2545         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
2546         struct tun_struct *tun = netdev_priv(dev);
2547
2548         if (dev->rtnl_link_ops != &tun_link_ops)
2549                 return NOTIFY_DONE;
2550
2551         switch (event) {
2552         case NETDEV_CHANGE_TX_QUEUE_LEN:
2553                 if (tun_queue_resize(tun))
2554                         return NOTIFY_BAD;
2555                 break;
2556         default:
2557                 break;
2558         }
2559
2560         return NOTIFY_DONE;
2561 }
2562
2563 static struct notifier_block tun_notifier_block __read_mostly = {
2564         .notifier_call  = tun_device_event,
2565 };
2566
2567 static int __init tun_init(void)
2568 {
2569         int ret = 0;
2570
2571         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2572         pr_info("%s\n", DRV_COPYRIGHT);
2573
2574         ret = rtnl_link_register(&tun_link_ops);
2575         if (ret) {
2576                 pr_err("Can't register link_ops\n");
2577                 goto err_linkops;
2578         }
2579
2580         ret = misc_register(&tun_miscdev);
2581         if (ret) {
2582                 pr_err("Can't register misc device %d\n", TUN_MINOR);
2583                 goto err_misc;
2584         }
2585
2586         register_netdevice_notifier(&tun_notifier_block);
2587         return  0;
2588 err_misc:
2589         rtnl_link_unregister(&tun_link_ops);
2590 err_linkops:
2591         return ret;
2592 }
2593
2594 static void tun_cleanup(void)
2595 {
2596         misc_deregister(&tun_miscdev);
2597         rtnl_link_unregister(&tun_link_ops);
2598         unregister_netdevice_notifier(&tun_notifier_block);
2599 }
2600
2601 /* Get an underlying socket object from tun file.  Returns error unless file is
2602  * attached to a device.  The returned object works like a packet socket, it
2603  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2604  * holding a reference to the file for as long as the socket is in use. */
2605 struct socket *tun_get_socket(struct file *file)
2606 {
2607         struct tun_file *tfile;
2608         if (file->f_op != &tun_fops)
2609                 return ERR_PTR(-EINVAL);
2610         tfile = file->private_data;
2611         if (!tfile)
2612                 return ERR_PTR(-EBADFD);
2613         return &tfile->socket;
2614 }
2615 EXPORT_SYMBOL_GPL(tun_get_socket);
2616
2617 module_init(tun_init);
2618 module_exit(tun_cleanup);
2619 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2620 MODULE_AUTHOR(DRV_COPYRIGHT);
2621 MODULE_LICENSE("GPL");
2622 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2623 MODULE_ALIAS("devname:net/tun");