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 <asm/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         struct tun_pcpu_stats __percpu *pcpu_stats;
 222 };
 223
 224 #ifdef CONFIG_TUN_VNET_CROSS_LE
 225 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 226 {
 227         return tun->flags & TUN_VNET_BE ? false :
 228                 virtio_legacy_is_little_endian();
 229 }
 230
 231 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 232 {
 233         int be = !!(tun->flags & TUN_VNET_BE);
 234
 235         if (put_user(be, argp))
 236                 return -EFAULT;
 237
 238         return 0;
 239 }
 240
 241 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 242 {
 243         int be;
 244
 245         if (get_user(be, argp))
 246                 return -EFAULT;
 247
 248         if (be)
 249                 tun->flags |= TUN_VNET_BE;
 250         else
 251                 tun->flags &= ~TUN_VNET_BE;
 252
 253         return 0;
 254 }
 255 #else
 256 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 257 {
 258         return virtio_legacy_is_little_endian();
 259 }
 260
 261 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 262 {
 263         return -EINVAL;
 264 }
 265
 266 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 267 {
 268         return -EINVAL;
 269 }
 270 #endif /* CONFIG_TUN_VNET_CROSS_LE */
 271
 272 static inline bool tun_is_little_endian(struct tun_struct *tun)
 273 {
 274         return tun->flags & TUN_VNET_LE ||
 275                 tun_legacy_is_little_endian(tun);
 276 }
 277
 278 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
 279 {
 280         return __virtio16_to_cpu(tun_is_little_endian(tun), val);
 281 }
 282
 283 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
 284 {
 285         return __cpu_to_virtio16(tun_is_little_endian(tun), val);
 286 }
 287
 288 static inline u32 tun_hashfn(u32 rxhash)
 289 {
 290         return rxhash & 0x3ff;
 291 }
 292
 293 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 294 {
 295         struct tun_flow_entry *e;
 296
 297         hlist_for_each_entry_rcu(e, head, hash_link) {
 298                 if (e->rxhash == rxhash)
 299                         return e;
 300         }
 301         return NULL;
 302 }
 303
 304 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 305                                               struct hlist_head *head,
 306                                               u32 rxhash, u16 queue_index)
 307 {
 308         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 309
 310         if (e) {
 311                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 312                           rxhash, queue_index);
 313                 e->updated = jiffies;
 314                 e->rxhash = rxhash;
 315                 e->rps_rxhash = 0;
 316                 e->queue_index = queue_index;
 317                 e->tun = tun;
 318                 hlist_add_head_rcu(&e->hash_link, head);
 319                 ++tun->flow_count;
 320         }
 321         return e;
 322 }
 323
 324 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 325 {
 326         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 327                   e->rxhash, e->queue_index);
 328         hlist_del_rcu(&e->hash_link);
 329         kfree_rcu(e, rcu);
 330         --tun->flow_count;
 331 }
 332
 333 static void tun_flow_flush(struct tun_struct *tun)
 334 {
 335         int i;
 336
 337         spin_lock_bh(&tun->lock);
 338         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 339                 struct tun_flow_entry *e;
 340                 struct hlist_node *n;
 341
 342                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 343                         tun_flow_delete(tun, e);
 344         }
 345         spin_unlock_bh(&tun->lock);
 346 }
 347
 348 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 349 {
 350         int i;
 351
 352         spin_lock_bh(&tun->lock);
 353         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 354                 struct tun_flow_entry *e;
 355                 struct hlist_node *n;
 356
 357                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 358                         if (e->queue_index == queue_index)
 359                                 tun_flow_delete(tun, e);
 360                 }
 361         }
 362         spin_unlock_bh(&tun->lock);
 363 }
 364
 365 static void tun_flow_cleanup(unsigned long data)
 366 {
 367         struct tun_struct *tun = (struct tun_struct *)data;
 368         unsigned long delay = tun->ageing_time;
 369         unsigned long next_timer = jiffies + delay;
 370         unsigned long count = 0;
 371         int i;
 372
 373         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 374
 375         spin_lock_bh(&tun->lock);
 376         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 377                 struct tun_flow_entry *e;
 378                 struct hlist_node *n;
 379
 380                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 381                         unsigned long this_timer;
 382                         count++;
 383                         this_timer = e->updated + delay;
 384                         if (time_before_eq(this_timer, jiffies))
 385                                 tun_flow_delete(tun, e);
 386                         else if (time_before(this_timer, next_timer))
 387                                 next_timer = this_timer;
 388                 }
 389         }
 390
 391         if (count)
 392                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 393         spin_unlock_bh(&tun->lock);
 394 }
 395
 396 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 397                             struct tun_file *tfile)
 398 {
 399         struct hlist_head *head;
 400         struct tun_flow_entry *e;
 401         unsigned long delay = tun->ageing_time;
 402         u16 queue_index = tfile->queue_index;
 403
 404         if (!rxhash)
 405                 return;
 406         else
 407                 head = &tun->flows[tun_hashfn(rxhash)];
 408
 409         rcu_read_lock();
 410
 411         /* We may get a very small possibility of OOO during switching, not
 412          * worth to optimize.*/
 413         if (tun->numqueues == 1 || tfile->detached)
 414                 goto unlock;
 415
 416         e = tun_flow_find(head, rxhash);
 417         if (likely(e)) {
 418                 /* TODO: keep queueing to old queue until it's empty? */
 419                 e->queue_index = queue_index;
 420                 e->updated = jiffies;
 421                 sock_rps_record_flow_hash(e->rps_rxhash);
 422         } else {
 423                 spin_lock_bh(&tun->lock);
 424                 if (!tun_flow_find(head, rxhash) &&
 425                     tun->flow_count < MAX_TAP_FLOWS)
 426                         tun_flow_create(tun, head, rxhash, queue_index);
 427
 428                 if (!timer_pending(&tun->flow_gc_timer))
 429                         mod_timer(&tun->flow_gc_timer,
 430                                   round_jiffies_up(jiffies + delay));
 431                 spin_unlock_bh(&tun->lock);
 432         }
 433
 434 unlock:
 435         rcu_read_unlock();
 436 }
 437
 438 /**
 439  * Save the hash received in the stack receive path and update the
 440  * flow_hash table accordingly.
 441  */
 442 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
 443 {
 444         if (unlikely(e->rps_rxhash != hash))
 445                 e->rps_rxhash = hash;
 446 }
 447
 448 /* We try to identify a flow through its rxhash first. The reason that
 449  * we do not check rxq no. is because some cards(e.g 82599), chooses
 450  * the rxq based on the txq where the last packet of the flow comes. As
 451  * the userspace application move between processors, we may get a
 452  * different rxq no. here. If we could not get rxhash, then we would
 453  * hope the rxq no. may help here.
 454  */
 455 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
 456                             void *accel_priv, select_queue_fallback_t fallback)
 457 {
 458         struct tun_struct *tun = netdev_priv(dev);
 459         struct tun_flow_entry *e;
 460         u32 txq = 0;
 461         u32 numqueues = 0;
 462
 463         rcu_read_lock();
 464         numqueues = ACCESS_ONCE(tun->numqueues);
 465
 466         txq = skb_get_hash(skb);
 467         if (txq) {
 468                 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 469                 if (e) {
 470                         tun_flow_save_rps_rxhash(e, txq);
 471                         txq = e->queue_index;
 472                 } else
 473                         /* use multiply and shift instead of expensive divide */
 474                         txq = ((u64)txq * numqueues) >> 32;
 475         } else if (likely(skb_rx_queue_recorded(skb))) {
 476                 txq = skb_get_rx_queue(skb);
 477                 while (unlikely(txq >= numqueues))
 478                         txq -= numqueues;
 479         }
 480
 481         rcu_read_unlock();
 482         return txq;
 483 }
 484
 485 static inline bool tun_not_capable(struct tun_struct *tun)
 486 {
 487         const struct cred *cred = current_cred();
 488         struct net *net = dev_net(tun->dev);
 489
 490         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 491                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 492                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 493 }
 494
 495 static void tun_set_real_num_queues(struct tun_struct *tun)
 496 {
 497         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 498         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 499 }
 500
 501 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 502 {
 503         tfile->detached = tun;
 504         list_add_tail(&tfile->next, &tun->disabled);
 505         ++tun->numdisabled;
 506 }
 507
 508 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 509 {
 510         struct tun_struct *tun = tfile->detached;
 511
 512         tfile->detached = NULL;
 513         list_del_init(&tfile->next);
 514         --tun->numdisabled;
 515         return tun;
 516 }
 517
 518 static void tun_queue_purge(struct tun_file *tfile)
 519 {
 520         struct sk_buff *skb;
 521
 522         while ((skb = skb_array_consume(&tfile->tx_array)) != NULL)
 523                 kfree_skb(skb);
 524
 525         skb_queue_purge(&tfile->sk.sk_error_queue);
 526 }
 527
 528 static void __tun_detach(struct tun_file *tfile, bool clean)
 529 {
 530         struct tun_file *ntfile;
 531         struct tun_struct *tun;
 532
 533         tun = rtnl_dereference(tfile->tun);
 534
 535         if (tun && !tfile->detached) {
 536                 u16 index = tfile->queue_index;
 537                 BUG_ON(index >= tun->numqueues);
 538
 539                 rcu_assign_pointer(tun->tfiles[index],
 540                                    tun->tfiles[tun->numqueues - 1]);
 541                 ntfile = rtnl_dereference(tun->tfiles[index]);
 542                 ntfile->queue_index = index;
 543
 544                 --tun->numqueues;
 545                 if (clean) {
 546                         RCU_INIT_POINTER(tfile->tun, NULL);
 547                         sock_put(&tfile->sk);
 548                 } else
 549                         tun_disable_queue(tun, tfile);
 550
 551                 synchronize_net();
 552                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 553                 /* Drop read queue */
 554                 tun_queue_purge(tfile);
 555                 tun_set_real_num_queues(tun);
 556         } else if (tfile->detached && clean) {
 557                 tun = tun_enable_queue(tfile);
 558                 sock_put(&tfile->sk);
 559         }
 560
 561         if (clean) {
 562                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 563                         netif_carrier_off(tun->dev);
 564
 565                         if (!(tun->flags & IFF_PERSIST) &&
 566                             tun->dev->reg_state == NETREG_REGISTERED)
 567                                 unregister_netdevice(tun->dev);
 568                 }
 569                 if (tun)
 570                         skb_array_cleanup(&tfile->tx_array);
 571                 sock_put(&tfile->sk);
 572         }
 573 }
 574
 575 static void tun_detach(struct tun_file *tfile, bool clean)
 576 {
 577         rtnl_lock();
 578         __tun_detach(tfile, clean);
 579         rtnl_unlock();
 580 }
 581
 582 static void tun_detach_all(struct net_device *dev)
 583 {
 584         struct tun_struct *tun = netdev_priv(dev);
 585         struct tun_file *tfile, *tmp;
 586         int i, n = tun->numqueues;
 587
 588         for (i = 0; i < n; i++) {
 589                 tfile = rtnl_dereference(tun->tfiles[i]);
 590                 BUG_ON(!tfile);
 591                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 592                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 593                 RCU_INIT_POINTER(tfile->tun, NULL);
 594                 --tun->numqueues;
 595         }
 596         list_for_each_entry(tfile, &tun->disabled, next) {
 597                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 598                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 599                 RCU_INIT_POINTER(tfile->tun, NULL);
 600         }
 601         BUG_ON(tun->numqueues != 0);
 602
 603         synchronize_net();
 604         for (i = 0; i < n; i++) {
 605                 tfile = rtnl_dereference(tun->tfiles[i]);
 606                 /* Drop read queue */
 607                 tun_queue_purge(tfile);
 608                 sock_put(&tfile->sk);
 609         }
 610         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 611                 tun_enable_queue(tfile);
 612                 tun_queue_purge(tfile);
 613                 sock_put(&tfile->sk);
 614         }
 615         BUG_ON(tun->numdisabled != 0);
 616
 617         if (tun->flags & IFF_PERSIST)
 618                 module_put(THIS_MODULE);
 619 }
 620
 621 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
 622 {
 623         struct tun_file *tfile = file->private_data;
 624         struct net_device *dev = tun->dev;
 625         int err;
 626
 627         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 628         if (err < 0)
 629                 goto out;
 630
 631         err = -EINVAL;
 632         if (rtnl_dereference(tfile->tun) && !tfile->detached)
 633                 goto out;
 634
 635         err = -EBUSY;
 636         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
 637                 goto out;
 638
 639         err = -E2BIG;
 640         if (!tfile->detached &&
 641             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 642                 goto out;
 643
 644         err = 0;
 645
 646         /* Re-attach the filter to persist device */
 647         if (!skip_filter && (tun->filter_attached == true)) {
 648                 lock_sock(tfile->socket.sk);
 649                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 650                 release_sock(tfile->socket.sk);
 651                 if (!err)
 652                         goto out;
 653         }
 654
 655         if (!tfile->detached &&
 656             skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL)) {
 657                 err = -ENOMEM;
 658                 goto out;
 659         }
 660
 661         tfile->queue_index = tun->numqueues;
 662         tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
 663         rcu_assign_pointer(tfile->tun, tun);
 664         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 665         tun->numqueues++;
 666
 667         if (tfile->detached)
 668                 tun_enable_queue(tfile);
 669         else
 670                 sock_hold(&tfile->sk);
 671
 672         tun_set_real_num_queues(tun);
 673
 674         /* device is allowed to go away first, so no need to hold extra
 675          * refcnt.
 676          */
 677
 678 out:
 679         return err;
 680 }
 681
 682 static struct tun_struct *__tun_get(struct tun_file *tfile)
 683 {
 684         struct tun_struct *tun;
 685
 686         rcu_read_lock();
 687         tun = rcu_dereference(tfile->tun);
 688         if (tun)
 689                 dev_hold(tun->dev);
 690         rcu_read_unlock();
 691
 692         return tun;
 693 }
 694
 695 static struct tun_struct *tun_get(struct file *file)
 696 {
 697         return __tun_get(file->private_data);
 698 }
 699
 700 static void tun_put(struct tun_struct *tun)
 701 {
 702         dev_put(tun->dev);
 703 }
 704
 705 /* TAP filtering */
 706 static void addr_hash_set(u32 *mask, const u8 *addr)
 707 {
 708         int n = ether_crc(ETH_ALEN, addr) >> 26;
 709         mask[n >> 5] |= (1 << (n & 31));
 710 }
 711
 712 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 713 {
 714         int n = ether_crc(ETH_ALEN, addr) >> 26;
 715         return mask[n >> 5] & (1 << (n & 31));
 716 }
 717
 718 static int update_filter(struct tap_filter *filter, void __user *arg)
 719 {
 720         struct { u8 u[ETH_ALEN]; } *addr;
 721         struct tun_filter uf;
 722         int err, alen, n, nexact;
 723
 724         if (copy_from_user(&uf, arg, sizeof(uf)))
 725                 return -EFAULT;
 726
 727         if (!uf.count) {
 728                 /* Disabled */
 729                 filter->count = 0;
 730                 return 0;
 731         }
 732
 733         alen = ETH_ALEN * uf.count;
 734         addr = kmalloc(alen, GFP_KERNEL);
 735         if (!addr)
 736                 return -ENOMEM;
 737
 738         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 739                 err = -EFAULT;
 740                 goto done;
 741         }
 742
 743         /* The filter is updated without holding any locks. Which is
 744          * perfectly safe. We disable it first and in the worst
 745          * case we'll accept a few undesired packets. */
 746         filter->count = 0;
 747         wmb();
 748
 749         /* Use first set of addresses as an exact filter */
 750         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 751                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 752
 753         nexact = n;
 754
 755         /* Remaining multicast addresses are hashed,
 756          * unicast will leave the filter disabled. */
 757         memset(filter->mask, 0, sizeof(filter->mask));
 758         for (; n < uf.count; n++) {
 759                 if (!is_multicast_ether_addr(addr[n].u)) {
 760                         err = 0; /* no filter */
 761                         goto done;
 762                 }
 763                 addr_hash_set(filter->mask, addr[n].u);
 764         }
 765
 766         /* For ALLMULTI just set the mask to all ones.
 767          * This overrides the mask populated above. */
 768         if ((uf.flags & TUN_FLT_ALLMULTI))
 769                 memset(filter->mask, ~0, sizeof(filter->mask));
 770
 771         /* Now enable the filter */
 772         wmb();
 773         filter->count = nexact;
 774
 775         /* Return the number of exact filters */
 776         err = nexact;
 777
 778 done:
 779         kfree(addr);
 780         return err;
 781 }
 782
 783 /* Returns: 0 - drop, !=0 - accept */
 784 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 785 {
 786         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 787          * at this point. */
 788         struct ethhdr *eh = (struct ethhdr *) skb->data;
 789         int i;
 790
 791         /* Exact match */
 792         for (i = 0; i < filter->count; i++)
 793                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 794                         return 1;
 795
 796         /* Inexact match (multicast only) */
 797         if (is_multicast_ether_addr(eh->h_dest))
 798                 return addr_hash_test(filter->mask, eh->h_dest);
 799
 800         return 0;
 801 }
 802
 803 /*
 804  * Checks whether the packet is accepted or not.
 805  * Returns: 0 - drop, !=0 - accept
 806  */
 807 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 808 {
 809         if (!filter->count)
 810                 return 1;
 811
 812         return run_filter(filter, skb);
 813 }
 814
 815 /* Network device part of the driver */
 816
 817 static const struct ethtool_ops tun_ethtool_ops;
 818
 819 /* Net device detach from fd. */
 820 static void tun_net_uninit(struct net_device *dev)
 821 {
 822         tun_detach_all(dev);
 823 }
 824
 825 /* Net device open. */
 826 static int tun_net_open(struct net_device *dev)
 827 {
 828         netif_tx_start_all_queues(dev);
 829         return 0;
 830 }
 831
 832 /* Net device close. */
 833 static int tun_net_close(struct net_device *dev)
 834 {
 835         netif_tx_stop_all_queues(dev);
 836         return 0;
 837 }
 838
 839 /* Net device start xmit */
 840 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 841 {
 842         struct tun_struct *tun = netdev_priv(dev);
 843         int txq = skb->queue_mapping;
 844         struct tun_file *tfile;
 845         u32 numqueues = 0;
 846
 847         rcu_read_lock();
 848         tfile = rcu_dereference(tun->tfiles[txq]);
 849         numqueues = ACCESS_ONCE(tun->numqueues);
 850
 851         /* Drop packet if interface is not attached */
 852         if (txq >= numqueues)
 853                 goto drop;
 854
 855 #ifdef CONFIG_RPS
 856         if (numqueues == 1 && static_key_false(&rps_needed)) {
 857                 /* Select queue was not called for the skbuff, so we extract the
 858                  * RPS hash and save it into the flow_table here.
 859                  */
 860                 __u32 rxhash;
 861
 862                 rxhash = skb_get_hash(skb);
 863                 if (rxhash) {
 864                         struct tun_flow_entry *e;
 865                         e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
 866                                         rxhash);
 867                         if (e)
 868                                 tun_flow_save_rps_rxhash(e, rxhash);
 869                 }
 870         }
 871 #endif
 872
 873         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 874
 875         BUG_ON(!tfile);
 876
 877         /* Drop if the filter does not like it.
 878          * This is a noop if the filter is disabled.
 879          * Filter can be enabled only for the TAP devices. */
 880         if (!check_filter(&tun->txflt, skb))
 881                 goto drop;
 882
 883         if (tfile->socket.sk->sk_filter &&
 884             sk_filter(tfile->socket.sk, skb))
 885                 goto drop;
 886
 887         /* Limit the number of packets queued by dividing txq length with the
 888          * number of queues.
 889          */
 890         if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues
 891                           >= dev->tx_queue_len)
 892                 goto drop;
 893
 894         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 895                 goto drop;
 896
 897         if (skb->sk && sk_fullsock(skb->sk)) {
 898                 sock_tx_timestamp(skb->sk, skb->sk->sk_tsflags,
 899                                   &skb_shinfo(skb)->tx_flags);
 900                 sw_tx_timestamp(skb);
 901         }
 902
 903         /* Orphan the skb - required as we might hang on to it
 904          * for indefinite time.
 905          */
 906         skb_orphan(skb);
 907
 908         nf_reset(skb);
 909
 910         if (skb_array_produce(&tfile->tx_array, skb))
 911                 goto drop;
 912
 913         /* Notify and wake up reader process */
 914         if (tfile->flags & TUN_FASYNC)
 915                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
 916         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 917
 918         rcu_read_unlock();
 919         return NETDEV_TX_OK;
 920
 921 drop:
 922         this_cpu_inc(tun->pcpu_stats->tx_dropped);
 923         skb_tx_error(skb);
 924         kfree_skb(skb);
 925         rcu_read_unlock();
 926         return NET_XMIT_DROP;
 927 }
 928
 929 static void tun_net_mclist(struct net_device *dev)
 930 {
 931         /*
 932          * This callback is supposed to deal with mc filter in
 933          * _rx_ path and has nothing to do with the _tx_ path.
 934          * In rx path we always accept everything userspace gives us.
 935          */
 936 }
 937
 938 #define MIN_MTU 68
 939 #define MAX_MTU 65535
 940
 941 static int
 942 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 943 {
 944         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 945                 return -EINVAL;
 946         dev->mtu = new_mtu;
 947         return 0;
 948 }
 949
 950 static netdev_features_t tun_net_fix_features(struct net_device *dev,
 951         netdev_features_t features)
 952 {
 953         struct tun_struct *tun = netdev_priv(dev);
 954
 955         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 956 }
 957 #ifdef CONFIG_NET_POLL_CONTROLLER
 958 static void tun_poll_controller(struct net_device *dev)
 959 {
 960         /*
 961          * Tun only receives frames when:
 962          * 1) the char device endpoint gets data from user space
 963          * 2) the tun socket gets a sendmsg call from user space
 964          * Since both of those are synchronous operations, we are guaranteed
 965          * never to have pending data when we poll for it
 966          * so there is nothing to do here but return.
 967          * We need this though so netpoll recognizes us as an interface that
 968          * supports polling, which enables bridge devices in virt setups to
 969          * still use netconsole
 970          */
 971         return;
 972 }
 973 #endif
 974
 975 static void tun_set_headroom(struct net_device *dev, int new_hr)
 976 {
 977         struct tun_struct *tun = netdev_priv(dev);
 978
 979         if (new_hr < NET_SKB_PAD)
 980                 new_hr = NET_SKB_PAD;
 981
 982         tun->align = new_hr;
 983 }
 984
 985 static struct rtnl_link_stats64 *
 986 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 987 {
 988         u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
 989         struct tun_struct *tun = netdev_priv(dev);
 990         struct tun_pcpu_stats *p;
 991         int i;
 992
 993         for_each_possible_cpu(i) {
 994                 u64 rxpackets, rxbytes, txpackets, txbytes;
 995                 unsigned int start;
 996
 997                 p = per_cpu_ptr(tun->pcpu_stats, i);
 998                 do {
 999                         start = u64_stats_fetch_begin(&p->syncp);
1000                         rxpackets       = p->rx_packets;
1001                         rxbytes         = p->rx_bytes;
1002                         txpackets       = p->tx_packets;
1003                         txbytes         = p->tx_bytes;
1004                 } while (u64_stats_fetch_retry(&p->syncp, start));
1005
1006                 stats->rx_packets       += rxpackets;
1007                 stats->rx_bytes         += rxbytes;
1008                 stats->tx_packets       += txpackets;
1009                 stats->tx_bytes         += txbytes;
1010
1011                 /* u32 counters */
1012                 rx_dropped      += p->rx_dropped;
1013                 rx_frame_errors += p->rx_frame_errors;
1014                 tx_dropped      += p->tx_dropped;
1015         }
1016         stats->rx_dropped  = rx_dropped;
1017         stats->rx_frame_errors = rx_frame_errors;
1018         stats->tx_dropped = tx_dropped;
1019         return stats;
1020 }
1021
1022 static const struct net_device_ops tun_netdev_ops = {
1023         .ndo_uninit             = tun_net_uninit,
1024         .ndo_open               = tun_net_open,
1025         .ndo_stop               = tun_net_close,
1026         .ndo_start_xmit         = tun_net_xmit,
1027         .ndo_change_mtu         = tun_net_change_mtu,
1028         .ndo_fix_features       = tun_net_fix_features,
1029         .ndo_select_queue       = tun_select_queue,
1030 #ifdef CONFIG_NET_POLL_CONTROLLER
1031         .ndo_poll_controller    = tun_poll_controller,
1032 #endif
1033         .ndo_set_rx_headroom    = tun_set_headroom,
1034         .ndo_get_stats64        = tun_net_get_stats64,
1035 };
1036
1037 static const struct net_device_ops tap_netdev_ops = {
1038         .ndo_uninit             = tun_net_uninit,
1039         .ndo_open               = tun_net_open,
1040         .ndo_stop               = tun_net_close,
1041         .ndo_start_xmit         = tun_net_xmit,
1042         .ndo_change_mtu         = tun_net_change_mtu,
1043         .ndo_fix_features       = tun_net_fix_features,
1044         .ndo_set_rx_mode        = tun_net_mclist,
1045         .ndo_set_mac_address    = eth_mac_addr,
1046         .ndo_validate_addr      = eth_validate_addr,
1047         .ndo_select_queue       = tun_select_queue,
1048 #ifdef CONFIG_NET_POLL_CONTROLLER
1049         .ndo_poll_controller    = tun_poll_controller,
1050 #endif
1051         .ndo_features_check     = passthru_features_check,
1052         .ndo_set_rx_headroom    = tun_set_headroom,
1053         .ndo_get_stats64        = tun_net_get_stats64,
1054 };
1055
1056 static void tun_flow_init(struct tun_struct *tun)
1057 {
1058         int i;
1059
1060         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1061                 INIT_HLIST_HEAD(&tun->flows[i]);
1062
1063         tun->ageing_time = TUN_FLOW_EXPIRE;
1064         setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
1065         mod_timer(&tun->flow_gc_timer,
1066                   round_jiffies_up(jiffies + tun->ageing_time));
1067 }
1068
1069 static void tun_flow_uninit(struct tun_struct *tun)
1070 {
1071         del_timer_sync(&tun->flow_gc_timer);
1072         tun_flow_flush(tun);
1073 }
1074
1075 /* Initialize net device. */
1076 static void tun_net_init(struct net_device *dev)
1077 {
1078         struct tun_struct *tun = netdev_priv(dev);
1079
1080         switch (tun->flags & TUN_TYPE_MASK) {
1081         case IFF_TUN:
1082                 dev->netdev_ops = &tun_netdev_ops;
1083
1084                 /* Point-to-Point TUN Device */
1085                 dev->hard_header_len = 0;
1086                 dev->addr_len = 0;
1087                 dev->mtu = 1500;
1088
1089                 /* Zero header length */
1090                 dev->type = ARPHRD_NONE;
1091                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1092                 break;
1093
1094         case IFF_TAP:
1095                 dev->netdev_ops = &tap_netdev_ops;
1096                 /* Ethernet TAP Device */
1097                 ether_setup(dev);
1098                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1099                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1100
1101                 eth_hw_addr_random(dev);
1102
1103                 break;
1104         }
1105 }
1106
1107 /* Character device part */
1108
1109 /* Poll */
1110 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1111 {
1112         struct tun_file *tfile = file->private_data;
1113         struct tun_struct *tun = __tun_get(tfile);
1114         struct sock *sk;
1115         unsigned int mask = 0;
1116
1117         if (!tun)
1118                 return POLLERR;
1119
1120         sk = tfile->socket.sk;
1121
1122         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1123
1124         poll_wait(file, sk_sleep(sk), wait);
1125
1126         if (!skb_array_empty(&tfile->tx_array))
1127                 mask |= POLLIN | POLLRDNORM;
1128
1129         if (sock_writeable(sk) ||
1130             (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1131              sock_writeable(sk)))
1132                 mask |= POLLOUT | POLLWRNORM;
1133
1134         if (tun->dev->reg_state != NETREG_REGISTERED)
1135                 mask = POLLERR;
1136
1137         tun_put(tun);
1138         return mask;
1139 }
1140
1141 /* prepad is the amount to reserve at front.  len is length after that.
1142  * linear is a hint as to how much to copy (usually headers). */
1143 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1144                                      size_t prepad, size_t len,
1145                                      size_t linear, int noblock)
1146 {
1147         struct sock *sk = tfile->socket.sk;
1148         struct sk_buff *skb;
1149         int err;
1150
1151         /* Under a page?  Don't bother with paged skb. */
1152         if (prepad + len < PAGE_SIZE || !linear)
1153                 linear = len;
1154
1155         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1156                                    &err, 0);
1157         if (!skb)
1158                 return ERR_PTR(err);
1159
1160         skb_reserve(skb, prepad);
1161         skb_put(skb, linear);
1162         skb->data_len = len - linear;
1163         skb->len += len - linear;
1164
1165         return skb;
1166 }
1167
1168 /* Get packet from user space buffer */
1169 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1170                             void *msg_control, struct iov_iter *from,
1171                             int noblock)
1172 {
1173         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1174         struct sk_buff *skb;
1175         size_t total_len = iov_iter_count(from);
1176         size_t len = total_len, align = tun->align, linear;
1177         struct virtio_net_hdr gso = { 0 };
1178         struct tun_pcpu_stats *stats;
1179         int good_linear;
1180         int copylen;
1181         bool zerocopy = false;
1182         int err;
1183         u32 rxhash;
1184         ssize_t n;
1185
1186         if (!(tun->dev->flags & IFF_UP))
1187                 return -EIO;
1188
1189         if (!(tun->flags & IFF_NO_PI)) {
1190                 if (len < sizeof(pi))
1191                         return -EINVAL;
1192                 len -= sizeof(pi);
1193
1194                 n = copy_from_iter(&pi, sizeof(pi), from);
1195                 if (n != sizeof(pi))
1196                         return -EFAULT;
1197         }
1198
1199         if (tun->flags & IFF_VNET_HDR) {
1200                 if (len < tun->vnet_hdr_sz)
1201                         return -EINVAL;
1202                 len -= tun->vnet_hdr_sz;
1203
1204                 n = copy_from_iter(&gso, sizeof(gso), from);
1205                 if (n != sizeof(gso))
1206                         return -EFAULT;
1207
1208                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1209                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1210                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1211
1212                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1213                         return -EINVAL;
1214                 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso));
1215         }
1216
1217         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1218                 align += NET_IP_ALIGN;
1219                 if (unlikely(len < ETH_HLEN ||
1220                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1221                         return -EINVAL;
1222         }
1223
1224         good_linear = SKB_MAX_HEAD(align);
1225
1226         if (msg_control) {
1227                 struct iov_iter i = *from;
1228
1229                 /* There are 256 bytes to be copied in skb, so there is
1230                  * enough room for skb expand head in case it is used.
1231                  * The rest of the buffer is mapped from userspace.
1232                  */
1233                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1234                 if (copylen > good_linear)
1235                         copylen = good_linear;
1236                 linear = copylen;
1237                 iov_iter_advance(&i, copylen);
1238                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1239                         zerocopy = true;
1240         }
1241
1242         if (!zerocopy) {
1243                 copylen = len;
1244                 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1245                         linear = good_linear;
1246                 else
1247                         linear = tun16_to_cpu(tun, gso.hdr_len);
1248         }
1249
1250         skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1251         if (IS_ERR(skb)) {
1252                 if (PTR_ERR(skb) != -EAGAIN)
1253                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1254                 return PTR_ERR(skb);
1255         }
1256
1257         if (zerocopy)
1258                 err = zerocopy_sg_from_iter(skb, from);
1259         else {
1260                 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1261                 if (!err && msg_control) {
1262                         struct ubuf_info *uarg = msg_control;
1263                         uarg->callback(uarg, false);
1264                 }
1265         }
1266
1267         if (err) {
1268                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1269                 kfree_skb(skb);
1270                 return -EFAULT;
1271         }
1272
1273         err = virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun));
1274         if (err) {
1275                 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1276                 kfree_skb(skb);
1277                 return -EINVAL;
1278         }
1279
1280         switch (tun->flags & TUN_TYPE_MASK) {
1281         case IFF_TUN:
1282                 if (tun->flags & IFF_NO_PI) {
1283                         switch (skb->data[0] & 0xf0) {
1284                         case 0x40:
1285                                 pi.proto = htons(ETH_P_IP);
1286                                 break;
1287                         case 0x60:
1288                                 pi.proto = htons(ETH_P_IPV6);
1289                                 break;
1290                         default:
1291                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1292                                 kfree_skb(skb);
1293                                 return -EINVAL;
1294                         }
1295                 }
1296
1297                 skb_reset_mac_header(skb);
1298                 skb->protocol = pi.proto;
1299                 skb->dev = tun->dev;
1300                 break;
1301         case IFF_TAP:
1302                 skb->protocol = eth_type_trans(skb, tun->dev);
1303                 break;
1304         }
1305
1306         /* copy skb_ubuf_info for callback when skb has no error */
1307         if (zerocopy) {
1308                 skb_shinfo(skb)->destructor_arg = msg_control;
1309                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1310                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1311         }
1312
1313         skb_reset_network_header(skb);
1314         skb_probe_transport_header(skb, 0);
1315
1316         rxhash = skb_get_hash(skb);
1317         netif_rx_ni(skb);
1318
1319         stats = get_cpu_ptr(tun->pcpu_stats);
1320         u64_stats_update_begin(&stats->syncp);
1321         stats->rx_packets++;
1322         stats->rx_bytes += len;
1323         u64_stats_update_end(&stats->syncp);
1324         put_cpu_ptr(stats);
1325
1326         tun_flow_update(tun, rxhash, tfile);
1327         return total_len;
1328 }
1329
1330 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1331 {
1332         struct file *file = iocb->ki_filp;
1333         struct tun_struct *tun = tun_get(file);
1334         struct tun_file *tfile = file->private_data;
1335         ssize_t result;
1336
1337         if (!tun)
1338                 return -EBADFD;
1339
1340         result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);
1341
1342         tun_put(tun);
1343         return result;
1344 }
1345
1346 /* Put packet to the user space buffer */
1347 static ssize_t tun_put_user(struct tun_struct *tun,
1348                             struct tun_file *tfile,
1349                             struct sk_buff *skb,
1350                             struct iov_iter *iter)
1351 {
1352         struct tun_pi pi = { 0, skb->protocol };
1353         struct tun_pcpu_stats *stats;
1354         ssize_t total;
1355         int vlan_offset = 0;
1356         int vlan_hlen = 0;
1357         int vnet_hdr_sz = 0;
1358
1359         if (skb_vlan_tag_present(skb))
1360                 vlan_hlen = VLAN_HLEN;
1361
1362         if (tun->flags & IFF_VNET_HDR)
1363                 vnet_hdr_sz = tun->vnet_hdr_sz;
1364
1365         total = skb->len + vlan_hlen + vnet_hdr_sz;
1366
1367         if (!(tun->flags & IFF_NO_PI)) {
1368                 if (iov_iter_count(iter) < sizeof(pi))
1369                         return -EINVAL;
1370
1371                 total += sizeof(pi);
1372                 if (iov_iter_count(iter) < total) {
1373                         /* Packet will be striped */
1374                         pi.flags |= TUN_PKT_STRIP;
1375                 }
1376
1377                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1378                         return -EFAULT;
1379         }
1380
1381         if (vnet_hdr_sz) {
1382                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1383                 int ret;
1384
1385                 if (iov_iter_count(iter) < vnet_hdr_sz)
1386                         return -EINVAL;
1387
1388                 ret = virtio_net_hdr_from_skb(skb, &gso,
1389                                               tun_is_little_endian(tun));
1390                 if (ret) {
1391                         struct skb_shared_info *sinfo = skb_shinfo(skb);
1392                         pr_err("unexpected GSO type: "
1393                                "0x%x, gso_size %d, hdr_len %d\n",
1394                                sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1395                                tun16_to_cpu(tun, gso.hdr_len));
1396                         print_hex_dump(KERN_ERR, "tun: ",
1397                                        DUMP_PREFIX_NONE,
1398                                        16, 1, skb->head,
1399                                        min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1400                         WARN_ON_ONCE(1);
1401                         return -EINVAL;
1402                 }
1403
1404                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1405                         return -EFAULT;
1406
1407                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1408         }
1409
1410         if (vlan_hlen) {
1411                 int ret;
1412                 struct {
1413                         __be16 h_vlan_proto;
1414                         __be16 h_vlan_TCI;
1415                 } veth;
1416
1417                 veth.h_vlan_proto = skb->vlan_proto;
1418                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1419
1420                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1421
1422                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1423                 if (ret || !iov_iter_count(iter))
1424                         goto done;
1425
1426                 ret = copy_to_iter(&veth, sizeof(veth), iter);
1427                 if (ret != sizeof(veth) || !iov_iter_count(iter))
1428                         goto done;
1429         }
1430
1431         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1432
1433 done:
1434         /* caller is in process context, */
1435         stats = get_cpu_ptr(tun->pcpu_stats);
1436         u64_stats_update_begin(&stats->syncp);
1437         stats->tx_packets++;
1438         stats->tx_bytes += skb->len + vlan_hlen;
1439         u64_stats_update_end(&stats->syncp);
1440         put_cpu_ptr(tun->pcpu_stats);
1441
1442         return total;
1443 }
1444
1445 static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
1446                                      int *err)
1447 {
1448         DECLARE_WAITQUEUE(wait, current);
1449         struct sk_buff *skb = NULL;
1450         int error = 0;
1451
1452         skb = skb_array_consume(&tfile->tx_array);
1453         if (skb)
1454                 goto out;
1455         if (noblock) {
1456                 error = -EAGAIN;
1457                 goto out;
1458         }
1459
1460         add_wait_queue(&tfile->wq.wait, &wait);
1461         current->state = TASK_INTERRUPTIBLE;
1462
1463         while (1) {
1464                 skb = skb_array_consume(&tfile->tx_array);
1465                 if (skb)
1466                         break;
1467                 if (signal_pending(current)) {
1468                         error = -ERESTARTSYS;
1469                         break;
1470                 }
1471                 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
1472                         error = -EFAULT;
1473                         break;
1474                 }
1475
1476                 schedule();
1477         }
1478
1479         current->state = TASK_RUNNING;
1480         remove_wait_queue(&tfile->wq.wait, &wait);
1481
1482 out:
1483         *err = error;
1484         return skb;
1485 }
1486
1487 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1488                            struct iov_iter *to,
1489                            int noblock)
1490 {
1491         struct sk_buff *skb;
1492         ssize_t ret;
1493         int err;
1494
1495         tun_debug(KERN_INFO, tun, "tun_do_read\n");
1496
1497         if (!iov_iter_count(to))
1498                 return 0;
1499
1500         /* Read frames from ring */
1501         skb = tun_ring_recv(tfile, noblock, &err);
1502         if (!skb)
1503                 return err;
1504
1505         ret = tun_put_user(tun, tfile, skb, to);
1506         if (unlikely(ret < 0))
1507                 kfree_skb(skb);
1508         else
1509                 consume_skb(skb);
1510
1511         return ret;
1512 }
1513
1514 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1515 {
1516         struct file *file = iocb->ki_filp;
1517         struct tun_file *tfile = file->private_data;
1518         struct tun_struct *tun = __tun_get(tfile);
1519         ssize_t len = iov_iter_count(to), ret;
1520
1521         if (!tun)
1522                 return -EBADFD;
1523         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
1524         ret = min_t(ssize_t, ret, len);
1525         if (ret > 0)
1526                 iocb->ki_pos = ret;
1527         tun_put(tun);
1528         return ret;
1529 }
1530
1531 static void tun_free_netdev(struct net_device *dev)
1532 {
1533         struct tun_struct *tun = netdev_priv(dev);
1534
1535         BUG_ON(!(list_empty(&tun->disabled)));
1536         free_percpu(tun->pcpu_stats);
1537         tun_flow_uninit(tun);
1538         security_tun_dev_free_security(tun->security);
1539         free_netdev(dev);
1540 }
1541
1542 static void tun_setup(struct net_device *dev)
1543 {
1544         struct tun_struct *tun = netdev_priv(dev);
1545
1546         tun->owner = INVALID_UID;
1547         tun->group = INVALID_GID;
1548
1549         dev->ethtool_ops = &tun_ethtool_ops;
1550         dev->destructor = tun_free_netdev;
1551         /* We prefer our own queue length */
1552         dev->tx_queue_len = TUN_READQ_SIZE;
1553 }
1554
1555 /* Trivial set of netlink ops to allow deleting tun or tap
1556  * device with netlink.
1557  */
1558 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1559 {
1560         return -EINVAL;
1561 }
1562
1563 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1564         .kind           = DRV_NAME,
1565         .priv_size      = sizeof(struct tun_struct),
1566         .setup          = tun_setup,
1567         .validate       = tun_validate,
1568 };
1569
1570 static void tun_sock_write_space(struct sock *sk)
1571 {
1572         struct tun_file *tfile;
1573         wait_queue_head_t *wqueue;
1574
1575         if (!sock_writeable(sk))
1576                 return;
1577
1578         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
1579                 return;
1580
1581         wqueue = sk_sleep(sk);
1582         if (wqueue && waitqueue_active(wqueue))
1583                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1584                                                 POLLWRNORM | POLLWRBAND);
1585
1586         tfile = container_of(sk, struct tun_file, sk);
1587         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1588 }
1589
1590 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1591 {
1592         int ret;
1593         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1594         struct tun_struct *tun = __tun_get(tfile);
1595
1596         if (!tun)
1597                 return -EBADFD;
1598
1599         ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1600                            m->msg_flags & MSG_DONTWAIT);
1601         tun_put(tun);
1602         return ret;
1603 }
1604
1605 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1606                        int flags)
1607 {
1608         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1609         struct tun_struct *tun = __tun_get(tfile);
1610         int ret;
1611
1612         if (!tun)
1613                 return -EBADFD;
1614
1615         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1616                 ret = -EINVAL;
1617                 goto out;
1618         }
1619         if (flags & MSG_ERRQUEUE) {
1620                 ret = sock_recv_errqueue(sock->sk, m, total_len,
1621                                          SOL_PACKET, TUN_TX_TIMESTAMP);
1622                 goto out;
1623         }
1624         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1625         if (ret > (ssize_t)total_len) {
1626                 m->msg_flags |= MSG_TRUNC;
1627                 ret = flags & MSG_TRUNC ? ret : total_len;
1628         }
1629 out:
1630         tun_put(tun);
1631         return ret;
1632 }
1633
1634 static int tun_peek_len(struct socket *sock)
1635 {
1636         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1637         struct tun_struct *tun;
1638         int ret = 0;
1639
1640         tun = __tun_get(tfile);
1641         if (!tun)
1642                 return 0;
1643
1644         ret = skb_array_peek_len(&tfile->tx_array);
1645         tun_put(tun);
1646
1647         return ret;
1648 }
1649
1650 /* Ops structure to mimic raw sockets with tun */
1651 static const struct proto_ops tun_socket_ops = {
1652         .peek_len = tun_peek_len,
1653         .sendmsg = tun_sendmsg,
1654         .recvmsg = tun_recvmsg,
1655 };
1656
1657 static struct proto tun_proto = {
1658         .name           = "tun",
1659         .owner          = THIS_MODULE,
1660         .obj_size       = sizeof(struct tun_file),
1661 };
1662
1663 static int tun_flags(struct tun_struct *tun)
1664 {
1665         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1666 }
1667
1668 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1669                               char *buf)
1670 {
1671         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1672         return sprintf(buf, "0x%x\n", tun_flags(tun));
1673 }
1674
1675 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1676                               char *buf)
1677 {
1678         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1679         return uid_valid(tun->owner)?
1680                 sprintf(buf, "%u\n",
1681                         from_kuid_munged(current_user_ns(), tun->owner)):
1682                 sprintf(buf, "-1\n");
1683 }
1684
1685 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1686                               char *buf)
1687 {
1688         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1689         return gid_valid(tun->group) ?
1690                 sprintf(buf, "%u\n",
1691                         from_kgid_munged(current_user_ns(), tun->group)):
1692                 sprintf(buf, "-1\n");
1693 }
1694
1695 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1696 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1697 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1698
1699 static struct attribute *tun_dev_attrs[] = {
1700         &dev_attr_tun_flags.attr,
1701         &dev_attr_owner.attr,
1702         &dev_attr_group.attr,
1703         NULL
1704 };
1705
1706 static const struct attribute_group tun_attr_group = {
1707         .attrs = tun_dev_attrs
1708 };
1709
1710 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1711 {
1712         struct tun_struct *tun;
1713         struct tun_file *tfile = file->private_data;
1714         struct net_device *dev;
1715         int err;
1716
1717         if (tfile->detached)
1718                 return -EINVAL;
1719
1720         dev = __dev_get_by_name(net, ifr->ifr_name);
1721         if (dev) {
1722                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1723                         return -EBUSY;
1724                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1725                         tun = netdev_priv(dev);
1726                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1727                         tun = netdev_priv(dev);
1728                 else
1729                         return -EINVAL;
1730
1731                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1732                     !!(tun->flags & IFF_MULTI_QUEUE))
1733                         return -EINVAL;
1734
1735                 if (tun_not_capable(tun))
1736                         return -EPERM;
1737                 err = security_tun_dev_open(tun->security);
1738                 if (err < 0)
1739                         return err;
1740
1741                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1742                 if (err < 0)
1743                         return err;
1744
1745                 if (tun->flags & IFF_MULTI_QUEUE &&
1746                     (tun->numqueues + tun->numdisabled > 1)) {
1747                         /* One or more queue has already been attached, no need
1748                          * to initialize the device again.
1749                          */
1750                         return 0;
1751                 }
1752         }
1753         else {
1754                 char *name;
1755                 unsigned long flags = 0;
1756                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1757                              MAX_TAP_QUEUES : 1;
1758
1759                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1760                         return -EPERM;
1761                 err = security_tun_dev_create();
1762                 if (err < 0)
1763                         return err;
1764
1765                 /* Set dev type */
1766                 if (ifr->ifr_flags & IFF_TUN) {
1767                         /* TUN device */
1768                         flags |= IFF_TUN;
1769                         name = "tun%d";
1770                 } else if (ifr->ifr_flags & IFF_TAP) {
1771                         /* TAP device */
1772                         flags |= IFF_TAP;
1773                         name = "tap%d";
1774                 } else
1775                         return -EINVAL;
1776
1777                 if (*ifr->ifr_name)
1778                         name = ifr->ifr_name;
1779
1780                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1781                                        NET_NAME_UNKNOWN, tun_setup, queues,
1782                                        queues);
1783
1784                 if (!dev)
1785                         return -ENOMEM;
1786
1787                 dev_net_set(dev, net);
1788                 dev->rtnl_link_ops = &tun_link_ops;
1789                 dev->ifindex = tfile->ifindex;
1790                 dev->sysfs_groups[0] = &tun_attr_group;
1791
1792                 tun = netdev_priv(dev);
1793                 tun->dev = dev;
1794                 tun->flags = flags;
1795                 tun->txflt.count = 0;
1796                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1797
1798                 tun->align = NET_SKB_PAD;
1799                 tun->filter_attached = false;
1800                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1801
1802                 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
1803                 if (!tun->pcpu_stats) {
1804                         err = -ENOMEM;
1805                         goto err_free_dev;
1806                 }
1807
1808                 spin_lock_init(&tun->lock);
1809
1810                 err = security_tun_dev_alloc_security(&tun->security);
1811                 if (err < 0)
1812                         goto err_free_stat;
1813
1814                 tun_net_init(dev);
1815                 tun_flow_init(tun);
1816
1817                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1818                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1819                                    NETIF_F_HW_VLAN_STAG_TX;
1820                 dev->features = dev->hw_features | NETIF_F_LLTX;
1821                 dev->vlan_features = dev->features &
1822                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
1823                                        NETIF_F_HW_VLAN_STAG_TX);
1824
1825                 INIT_LIST_HEAD(&tun->disabled);
1826                 err = tun_attach(tun, file, false);
1827                 if (err < 0)
1828                         goto err_free_flow;
1829
1830                 err = register_netdevice(tun->dev);
1831                 if (err < 0)
1832                         goto err_detach;
1833         }
1834
1835         netif_carrier_on(tun->dev);
1836
1837         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1838
1839         tun->flags = (tun->flags & ~TUN_FEATURES) |
1840                 (ifr->ifr_flags & TUN_FEATURES);
1841
1842         /* Make sure persistent devices do not get stuck in
1843          * xoff state.
1844          */
1845         if (netif_running(tun->dev))
1846                 netif_tx_wake_all_queues(tun->dev);
1847
1848         strcpy(ifr->ifr_name, tun->dev->name);
1849         return 0;
1850
1851 err_detach:
1852         tun_detach_all(dev);
1853 err_free_flow:
1854         tun_flow_uninit(tun);
1855         security_tun_dev_free_security(tun->security);
1856 err_free_stat:
1857         free_percpu(tun->pcpu_stats);
1858 err_free_dev:
1859         free_netdev(dev);
1860         return err;
1861 }
1862
1863 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1864                        struct ifreq *ifr)
1865 {
1866         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1867
1868         strcpy(ifr->ifr_name, tun->dev->name);
1869
1870         ifr->ifr_flags = tun_flags(tun);
1871
1872 }
1873
1874 /* This is like a cut-down ethtool ops, except done via tun fd so no
1875  * privs required. */
1876 static int set_offload(struct tun_struct *tun, unsigned long arg)
1877 {
1878         netdev_features_t features = 0;
1879
1880         if (arg & TUN_F_CSUM) {
1881                 features |= NETIF_F_HW_CSUM;
1882                 arg &= ~TUN_F_CSUM;
1883
1884                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1885                         if (arg & TUN_F_TSO_ECN) {
1886                                 features |= NETIF_F_TSO_ECN;
1887                                 arg &= ~TUN_F_TSO_ECN;
1888                         }
1889                         if (arg & TUN_F_TSO4)
1890                                 features |= NETIF_F_TSO;
1891                         if (arg & TUN_F_TSO6)
1892                                 features |= NETIF_F_TSO6;
1893                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1894                 }
1895
1896                 if (arg & TUN_F_UFO) {
1897                         features |= NETIF_F_UFO;
1898                         arg &= ~TUN_F_UFO;
1899                 }
1900         }
1901
1902         /* This gives the user a way to test for new features in future by
1903          * trying to set them. */
1904         if (arg)
1905                 return -EINVAL;
1906
1907         tun->set_features = features;
1908         netdev_update_features(tun->dev);
1909
1910         return 0;
1911 }
1912
1913 static void tun_detach_filter(struct tun_struct *tun, int n)
1914 {
1915         int i;
1916         struct tun_file *tfile;
1917
1918         for (i = 0; i < n; i++) {
1919                 tfile = rtnl_dereference(tun->tfiles[i]);
1920                 lock_sock(tfile->socket.sk);
1921                 sk_detach_filter(tfile->socket.sk);
1922                 release_sock(tfile->socket.sk);
1923         }
1924
1925         tun->filter_attached = false;
1926 }
1927
1928 static int tun_attach_filter(struct tun_struct *tun)
1929 {
1930         int i, ret = 0;
1931         struct tun_file *tfile;
1932
1933         for (i = 0; i < tun->numqueues; i++) {
1934                 tfile = rtnl_dereference(tun->tfiles[i]);
1935                 lock_sock(tfile->socket.sk);
1936                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1937                 release_sock(tfile->socket.sk);
1938                 if (ret) {
1939                         tun_detach_filter(tun, i);
1940                         return ret;
1941                 }
1942         }
1943
1944         tun->filter_attached = true;
1945         return ret;
1946 }
1947
1948 static void tun_set_sndbuf(struct tun_struct *tun)
1949 {
1950         struct tun_file *tfile;
1951         int i;
1952
1953         for (i = 0; i < tun->numqueues; i++) {
1954                 tfile = rtnl_dereference(tun->tfiles[i]);
1955                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1956         }
1957 }
1958
1959 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1960 {
1961         struct tun_file *tfile = file->private_data;
1962         struct tun_struct *tun;
1963         int ret = 0;
1964
1965         rtnl_lock();
1966
1967         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1968                 tun = tfile->detached;
1969                 if (!tun) {
1970                         ret = -EINVAL;
1971                         goto unlock;
1972                 }
1973                 ret = security_tun_dev_attach_queue(tun->security);
1974                 if (ret < 0)
1975                         goto unlock;
1976                 ret = tun_attach(tun, file, false);
1977         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1978                 tun = rtnl_dereference(tfile->tun);
1979                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1980                         ret = -EINVAL;
1981                 else
1982                         __tun_detach(tfile, false);
1983         } else
1984                 ret = -EINVAL;
1985
1986 unlock:
1987         rtnl_unlock();
1988         return ret;
1989 }
1990
1991 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1992                             unsigned long arg, int ifreq_len)
1993 {
1994         struct tun_file *tfile = file->private_data;
1995         struct tun_struct *tun;
1996         void __user* argp = (void __user*)arg;
1997         struct ifreq ifr;
1998         kuid_t owner;
1999         kgid_t group;
2000         int sndbuf;
2001         int vnet_hdr_sz;
2002         unsigned int ifindex;
2003         int le;
2004         int ret;
2005
2006         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
2007                 if (copy_from_user(&ifr, argp, ifreq_len))
2008                         return -EFAULT;
2009         } else {
2010                 memset(&ifr, 0, sizeof(ifr));
2011         }
2012         if (cmd == TUNGETFEATURES) {
2013                 /* Currently this just means: "what IFF flags are valid?".
2014                  * This is needed because we never checked for invalid flags on
2015                  * TUNSETIFF.
2016                  */
2017                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2018                                 (unsigned int __user*)argp);
2019         } else if (cmd == TUNSETQUEUE)
2020                 return tun_set_queue(file, &ifr);
2021
2022         ret = 0;
2023         rtnl_lock();
2024
2025         tun = __tun_get(tfile);
2026         if (cmd == TUNSETIFF && !tun) {
2027                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2028
2029                 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
2030
2031                 if (ret)
2032                         goto unlock;
2033
2034                 if (copy_to_user(argp, &ifr, ifreq_len))
2035                         ret = -EFAULT;
2036                 goto unlock;
2037         }
2038         if (cmd == TUNSETIFINDEX) {
2039                 ret = -EPERM;
2040                 if (tun)
2041                         goto unlock;
2042
2043                 ret = -EFAULT;
2044                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2045                         goto unlock;
2046
2047                 ret = 0;
2048                 tfile->ifindex = ifindex;
2049                 goto unlock;
2050         }
2051
2052         ret = -EBADFD;
2053         if (!tun)
2054                 goto unlock;
2055
2056         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2057
2058         ret = 0;
2059         switch (cmd) {
2060         case TUNGETIFF:
2061                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2062
2063                 if (tfile->detached)
2064                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
2065                 if (!tfile->socket.sk->sk_filter)
2066                         ifr.ifr_flags |= IFF_NOFILTER;
2067
2068                 if (copy_to_user(argp, &ifr, ifreq_len))
2069                         ret = -EFAULT;
2070                 break;
2071
2072         case TUNSETNOCSUM:
2073                 /* Disable/Enable checksum */
2074
2075                 /* [unimplemented] */
2076                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2077                           arg ? "disabled" : "enabled");
2078                 break;
2079
2080         case TUNSETPERSIST:
2081                 /* Disable/Enable persist mode. Keep an extra reference to the
2082                  * module to prevent the module being unprobed.
2083                  */
2084                 if (arg && !(tun->flags & IFF_PERSIST)) {
2085                         tun->flags |= IFF_PERSIST;
2086                         __module_get(THIS_MODULE);
2087                 }
2088                 if (!arg && (tun->flags & IFF_PERSIST)) {
2089                         tun->flags &= ~IFF_PERSIST;
2090                         module_put(THIS_MODULE);
2091                 }
2092
2093                 tun_debug(KERN_INFO, tun, "persist %s\n",
2094                           arg ? "enabled" : "disabled");
2095                 break;
2096
2097         case TUNSETOWNER:
2098                 /* Set owner of the device */
2099                 owner = make_kuid(current_user_ns(), arg);
2100                 if (!uid_valid(owner)) {
2101                         ret = -EINVAL;
2102                         break;
2103                 }
2104                 tun->owner = owner;
2105                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2106                           from_kuid(&init_user_ns, tun->owner));
2107                 break;
2108
2109         case TUNSETGROUP:
2110                 /* Set group of the device */
2111                 group = make_kgid(current_user_ns(), arg);
2112                 if (!gid_valid(group)) {
2113                         ret = -EINVAL;
2114                         break;
2115                 }
2116                 tun->group = group;
2117                 tun_debug(KERN_INFO, tun, "group set to %u\n",
2118                           from_kgid(&init_user_ns, tun->group));
2119                 break;
2120
2121         case TUNSETLINK:
2122                 /* Only allow setting the type when the interface is down */
2123                 if (tun->dev->flags & IFF_UP) {
2124                         tun_debug(KERN_INFO, tun,
2125                                   "Linktype set failed because interface is up\n");
2126                         ret = -EBUSY;
2127                 } else {
2128                         tun->dev->type = (int) arg;
2129                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2130                                   tun->dev->type);
2131                         ret = 0;
2132                 }
2133                 break;
2134
2135 #ifdef TUN_DEBUG
2136         case TUNSETDEBUG:
2137                 tun->debug = arg;
2138                 break;
2139 #endif
2140         case TUNSETOFFLOAD:
2141                 ret = set_offload(tun, arg);
2142                 break;
2143
2144         case TUNSETTXFILTER:
2145                 /* Can be set only for TAPs */
2146                 ret = -EINVAL;
2147                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2148                         break;
2149                 ret = update_filter(&tun->txflt, (void __user *)arg);
2150                 break;
2151
2152         case SIOCGIFHWADDR:
2153                 /* Get hw address */
2154                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2155                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2156                 if (copy_to_user(argp, &ifr, ifreq_len))
2157                         ret = -EFAULT;
2158                 break;
2159
2160         case SIOCSIFHWADDR:
2161                 /* Set hw address */
2162                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2163                           ifr.ifr_hwaddr.sa_data);
2164
2165                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2166                 break;
2167
2168         case TUNGETSNDBUF:
2169                 sndbuf = tfile->socket.sk->sk_sndbuf;
2170                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2171                         ret = -EFAULT;
2172                 break;
2173
2174         case TUNSETSNDBUF:
2175                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2176                         ret = -EFAULT;
2177                         break;
2178                 }
2179
2180                 tun->sndbuf = sndbuf;
2181                 tun_set_sndbuf(tun);
2182                 break;
2183
2184         case TUNGETVNETHDRSZ:
2185                 vnet_hdr_sz = tun->vnet_hdr_sz;
2186                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2187                         ret = -EFAULT;
2188                 break;
2189
2190         case TUNSETVNETHDRSZ:
2191                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2192                         ret = -EFAULT;
2193                         break;
2194                 }
2195                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2196                         ret = -EINVAL;
2197                         break;
2198                 }
2199
2200                 tun->vnet_hdr_sz = vnet_hdr_sz;
2201                 break;
2202
2203         case TUNGETVNETLE:
2204                 le = !!(tun->flags & TUN_VNET_LE);
2205                 if (put_user(le, (int __user *)argp))
2206                         ret = -EFAULT;
2207                 break;
2208
2209         case TUNSETVNETLE:
2210                 if (get_user(le, (int __user *)argp)) {
2211                         ret = -EFAULT;
2212                         break;
2213                 }
2214                 if (le)
2215                         tun->flags |= TUN_VNET_LE;
2216                 else
2217                         tun->flags &= ~TUN_VNET_LE;
2218                 break;
2219
2220         case TUNGETVNETBE:
2221                 ret = tun_get_vnet_be(tun, argp);
2222                 break;
2223
2224         case TUNSETVNETBE:
2225                 ret = tun_set_vnet_be(tun, argp);
2226                 break;
2227
2228         case TUNATTACHFILTER:
2229                 /* Can be set only for TAPs */
2230                 ret = -EINVAL;
2231                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2232                         break;
2233                 ret = -EFAULT;
2234                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2235                         break;
2236
2237                 ret = tun_attach_filter(tun);
2238                 break;
2239
2240         case TUNDETACHFILTER:
2241                 /* Can be set only for TAPs */
2242                 ret = -EINVAL;
2243                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2244                         break;
2245                 ret = 0;
2246                 tun_detach_filter(tun, tun->numqueues);
2247                 break;
2248
2249         case TUNGETFILTER:
2250                 ret = -EINVAL;
2251                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2252                         break;
2253                 ret = -EFAULT;
2254                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2255                         break;
2256                 ret = 0;
2257                 break;
2258
2259         default:
2260                 ret = -EINVAL;
2261                 break;
2262         }
2263
2264 unlock:
2265         rtnl_unlock();
2266         if (tun)
2267                 tun_put(tun);
2268         return ret;
2269 }
2270
2271 static long tun_chr_ioctl(struct file *file,
2272                           unsigned int cmd, unsigned long arg)
2273 {
2274         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2275 }
2276
2277 #ifdef CONFIG_COMPAT
2278 static long tun_chr_compat_ioctl(struct file *file,
2279                          unsigned int cmd, unsigned long arg)
2280 {
2281         switch (cmd) {
2282         case TUNSETIFF:
2283         case TUNGETIFF:
2284         case TUNSETTXFILTER:
2285         case TUNGETSNDBUF:
2286         case TUNSETSNDBUF:
2287         case SIOCGIFHWADDR:
2288         case SIOCSIFHWADDR:
2289                 arg = (unsigned long)compat_ptr(arg);
2290                 break;
2291         default:
2292                 arg = (compat_ulong_t)arg;
2293                 break;
2294         }
2295
2296         /*
2297          * compat_ifreq is shorter than ifreq, so we must not access beyond
2298          * the end of that structure. All fields that are used in this
2299          * driver are compatible though, we don't need to convert the
2300          * contents.
2301          */
2302         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2303 }
2304 #endif /* CONFIG_COMPAT */
2305
2306 static int tun_chr_fasync(int fd, struct file *file, int on)
2307 {
2308         struct tun_file *tfile = file->private_data;
2309         int ret;
2310
2311         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2312                 goto out;
2313
2314         if (on) {
2315                 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2316                 tfile->flags |= TUN_FASYNC;
2317         } else
2318                 tfile->flags &= ~TUN_FASYNC;
2319         ret = 0;
2320 out:
2321         return ret;
2322 }
2323
2324 static int tun_chr_open(struct inode *inode, struct file * file)
2325 {
2326         struct net *net = current->nsproxy->net_ns;
2327         struct tun_file *tfile;
2328
2329         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2330
2331         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2332                                             &tun_proto, 0);
2333         if (!tfile)
2334                 return -ENOMEM;
2335         RCU_INIT_POINTER(tfile->tun, NULL);
2336         tfile->flags = 0;
2337         tfile->ifindex = 0;
2338
2339         init_waitqueue_head(&tfile->wq.wait);
2340         RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2341
2342         tfile->socket.file = file;
2343         tfile->socket.ops = &tun_socket_ops;
2344
2345         sock_init_data(&tfile->socket, &tfile->sk);
2346
2347         tfile->sk.sk_write_space = tun_sock_write_space;
2348         tfile->sk.sk_sndbuf = INT_MAX;
2349
2350         file->private_data = tfile;
2351         INIT_LIST_HEAD(&tfile->next);
2352
2353         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2354
2355         return 0;
2356 }
2357
2358 static int tun_chr_close(struct inode *inode, struct file *file)
2359 {
2360         struct tun_file *tfile = file->private_data;
2361
2362         tun_detach(tfile, true);
2363
2364         return 0;
2365 }
2366
2367 #ifdef CONFIG_PROC_FS
2368 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2369 {
2370         struct tun_struct *tun;
2371         struct ifreq ifr;
2372
2373         memset(&ifr, 0, sizeof(ifr));
2374
2375         rtnl_lock();
2376         tun = tun_get(f);
2377         if (tun)
2378                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2379         rtnl_unlock();
2380
2381         if (tun)
2382                 tun_put(tun);
2383
2384         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2385 }
2386 #endif
2387
2388 static const struct file_operations tun_fops = {
2389         .owner  = THIS_MODULE,
2390         .llseek = no_llseek,
2391         .read_iter  = tun_chr_read_iter,
2392         .write_iter = tun_chr_write_iter,
2393         .poll   = tun_chr_poll,
2394         .unlocked_ioctl = tun_chr_ioctl,
2395 #ifdef CONFIG_COMPAT
2396         .compat_ioctl = tun_chr_compat_ioctl,
2397 #endif
2398         .open   = tun_chr_open,
2399         .release = tun_chr_close,
2400         .fasync = tun_chr_fasync,
2401 #ifdef CONFIG_PROC_FS
2402         .show_fdinfo = tun_chr_show_fdinfo,
2403 #endif
2404 };
2405
2406 static struct miscdevice tun_miscdev = {
2407         .minor = TUN_MINOR,
2408         .name = "tun",
2409         .nodename = "net/tun",
2410         .fops = &tun_fops,
2411 };
2412
2413 /* ethtool interface */
2414
2415 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2416 {
2417         cmd->supported          = 0;
2418         cmd->advertising        = 0;
2419         ethtool_cmd_speed_set(cmd, SPEED_10);
2420         cmd->duplex             = DUPLEX_FULL;
2421         cmd->port               = PORT_TP;
2422         cmd->phy_address        = 0;
2423         cmd->transceiver        = XCVR_INTERNAL;
2424         cmd->autoneg            = AUTONEG_DISABLE;
2425         cmd->maxtxpkt           = 0;
2426         cmd->maxrxpkt           = 0;
2427         return 0;
2428 }
2429
2430 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2431 {
2432         struct tun_struct *tun = netdev_priv(dev);
2433
2434         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2435         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2436
2437         switch (tun->flags & TUN_TYPE_MASK) {
2438         case IFF_TUN:
2439                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2440                 break;
2441         case IFF_TAP:
2442                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2443                 break;
2444         }
2445 }
2446
2447 static u32 tun_get_msglevel(struct net_device *dev)
2448 {
2449 #ifdef TUN_DEBUG
2450         struct tun_struct *tun = netdev_priv(dev);
2451         return tun->debug;
2452 #else
2453         return -EOPNOTSUPP;
2454 #endif
2455 }
2456
2457 static void tun_set_msglevel(struct net_device *dev, u32 value)
2458 {
2459 #ifdef TUN_DEBUG
2460         struct tun_struct *tun = netdev_priv(dev);
2461         tun->debug = value;
2462 #endif
2463 }
2464
2465 static const struct ethtool_ops tun_ethtool_ops = {
2466         .get_settings   = tun_get_settings,
2467         .get_drvinfo    = tun_get_drvinfo,
2468         .get_msglevel   = tun_get_msglevel,
2469         .set_msglevel   = tun_set_msglevel,
2470         .get_link       = ethtool_op_get_link,
2471         .get_ts_info    = ethtool_op_get_ts_info,
2472 };
2473
2474 static int tun_queue_resize(struct tun_struct *tun)
2475 {
2476         struct net_device *dev = tun->dev;
2477         struct tun_file *tfile;
2478         struct skb_array **arrays;
2479         int n = tun->numqueues + tun->numdisabled;
2480         int ret, i;
2481
2482         arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL);
2483         if (!arrays)
2484                 return -ENOMEM;
2485
2486         for (i = 0; i < tun->numqueues; i++) {
2487                 tfile = rtnl_dereference(tun->tfiles[i]);
2488                 arrays[i] = &tfile->tx_array;
2489         }
2490         list_for_each_entry(tfile, &tun->disabled, next)
2491                 arrays[i++] = &tfile->tx_array;
2492
2493         ret = skb_array_resize_multiple(arrays, n,
2494                                         dev->tx_queue_len, GFP_KERNEL);
2495
2496         kfree(arrays);
2497         return ret;
2498 }
2499
2500 static int tun_device_event(struct notifier_block *unused,
2501                             unsigned long event, void *ptr)
2502 {
2503         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
2504         struct tun_struct *tun = netdev_priv(dev);
2505
2506         if (dev->rtnl_link_ops != &tun_link_ops)
2507                 return NOTIFY_DONE;
2508
2509         switch (event) {
2510         case NETDEV_CHANGE_TX_QUEUE_LEN:
2511                 if (tun_queue_resize(tun))
2512                         return NOTIFY_BAD;
2513                 break;
2514         default:
2515                 break;
2516         }
2517
2518         return NOTIFY_DONE;
2519 }
2520
2521 static struct notifier_block tun_notifier_block __read_mostly = {
2522         .notifier_call  = tun_device_event,
2523 };
2524
2525 static int __init tun_init(void)
2526 {
2527         int ret = 0;
2528
2529         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2530         pr_info("%s\n", DRV_COPYRIGHT);
2531
2532         ret = rtnl_link_register(&tun_link_ops);
2533         if (ret) {
2534                 pr_err("Can't register link_ops\n");
2535                 goto err_linkops;
2536         }
2537
2538         ret = misc_register(&tun_miscdev);
2539         if (ret) {
2540                 pr_err("Can't register misc device %d\n", TUN_MINOR);
2541                 goto err_misc;
2542         }
2543
2544         register_netdevice_notifier(&tun_notifier_block);
2545         return  0;
2546 err_misc:
2547         rtnl_link_unregister(&tun_link_ops);
2548 err_linkops:
2549         return ret;
2550 }
2551
2552 static void tun_cleanup(void)
2553 {
2554         misc_deregister(&tun_miscdev);
2555         rtnl_link_unregister(&tun_link_ops);
2556         unregister_netdevice_notifier(&tun_notifier_block);
2557 }
2558
2559 /* Get an underlying socket object from tun file.  Returns error unless file is
2560  * attached to a device.  The returned object works like a packet socket, it
2561  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2562  * holding a reference to the file for as long as the socket is in use. */
2563 struct socket *tun_get_socket(struct file *file)
2564 {
2565         struct tun_file *tfile;
2566         if (file->f_op != &tun_fops)
2567                 return ERR_PTR(-EINVAL);
2568         tfile = file->private_data;
2569         if (!tfile)
2570                 return ERR_PTR(-EBADFD);
2571         return &tfile->socket;
2572 }
2573 EXPORT_SYMBOL_GPL(tun_get_socket);
2574
2575 module_init(tun_init);
2576 module_exit(tun_cleanup);
2577 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2578 MODULE_AUTHOR(DRV_COPYRIGHT);
2579 MODULE_LICENSE("GPL");
2580 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2581 MODULE_ALIAS("devname:net/tun");