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 = memdup_user(arg + sizeof(uf), alen);
 735         if (IS_ERR(addr))
 736                 return PTR_ERR(addr);
 737
 738         /* The filter is updated without holding any locks. Which is
 739          * perfectly safe. We disable it first and in the worst
 740          * case we'll accept a few undesired packets. */
 741         filter->count = 0;
 742         wmb();
 743
 744         /* Use first set of addresses as an exact filter */
 745         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 746                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 747
 748         nexact = n;
 749
 750         /* Remaining multicast addresses are hashed,
 751          * unicast will leave the filter disabled. */
 752         memset(filter->mask, 0, sizeof(filter->mask));
 753         for (; n < uf.count; n++) {
 754                 if (!is_multicast_ether_addr(addr[n].u)) {
 755                         err = 0; /* no filter */
 756                         goto free_addr;
 757                 }
 758                 addr_hash_set(filter->mask, addr[n].u);
 759         }
 760
 761         /* For ALLMULTI just set the mask to all ones.
 762          * This overrides the mask populated above. */
 763         if ((uf.flags & TUN_FLT_ALLMULTI))
 764                 memset(filter->mask, ~0, sizeof(filter->mask));
 765
 766         /* Now enable the filter */
 767         wmb();
 768         filter->count = nexact;
 769
 770         /* Return the number of exact filters */
 771         err = nexact;
 772 free_addr:
 773         kfree(addr);
 774         return err;
 775 }
 776
 777 /* Returns: 0 - drop, !=0 - accept */
 778 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 779 {
 780         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 781          * at this point. */
 782         struct ethhdr *eh = (struct ethhdr *) skb->data;
 783         int i;
 784
 785         /* Exact match */
 786         for (i = 0; i < filter->count; i++)
 787                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 788                         return 1;
 789
 790         /* Inexact match (multicast only) */
 791         if (is_multicast_ether_addr(eh->h_dest))
 792                 return addr_hash_test(filter->mask, eh->h_dest);
 793
 794         return 0;
 795 }
 796
 797 /*
 798  * Checks whether the packet is accepted or not.
 799  * Returns: 0 - drop, !=0 - accept
 800  */
 801 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 802 {
 803         if (!filter->count)
 804                 return 1;
 805
 806         return run_filter(filter, skb);
 807 }
 808
 809 /* Network device part of the driver */
 810
 811 static const struct ethtool_ops tun_ethtool_ops;
 812
 813 /* Net device detach from fd. */
 814 static void tun_net_uninit(struct net_device *dev)
 815 {
 816         tun_detach_all(dev);
 817 }
 818
 819 /* Net device open. */
 820 static int tun_net_open(struct net_device *dev)
 821 {
 822         netif_tx_start_all_queues(dev);
 823         return 0;
 824 }
 825
 826 /* Net device close. */
 827 static int tun_net_close(struct net_device *dev)
 828 {
 829         netif_tx_stop_all_queues(dev);
 830         return 0;
 831 }
 832
 833 /* Net device start xmit */
 834 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 835 {
 836         struct tun_struct *tun = netdev_priv(dev);
 837         int txq = skb->queue_mapping;
 838         struct tun_file *tfile;
 839         u32 numqueues = 0;
 840
 841         rcu_read_lock();
 842         tfile = rcu_dereference(tun->tfiles[txq]);
 843         numqueues = ACCESS_ONCE(tun->numqueues);
 844
 845         /* Drop packet if interface is not attached */
 846         if (txq >= numqueues)
 847                 goto drop;
 848
 849 #ifdef CONFIG_RPS
 850         if (numqueues == 1 && static_key_false(&rps_needed)) {
 851                 /* Select queue was not called for the skbuff, so we extract the
 852                  * RPS hash and save it into the flow_table here.
 853                  */
 854                 __u32 rxhash;
 855
 856                 rxhash = skb_get_hash(skb);
 857                 if (rxhash) {
 858                         struct tun_flow_entry *e;
 859                         e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
 860                                         rxhash);
 861                         if (e)
 862                                 tun_flow_save_rps_rxhash(e, rxhash);
 863                 }
 864         }
 865 #endif
 866
 867         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 868
 869         BUG_ON(!tfile);
 870
 871         /* Drop if the filter does not like it.
 872          * This is a noop if the filter is disabled.
 873          * Filter can be enabled only for the TAP devices. */
 874         if (!check_filter(&tun->txflt, skb))
 875                 goto drop;
 876
 877         if (tfile->socket.sk->sk_filter &&
 878             sk_filter(tfile->socket.sk, skb))
 879                 goto drop;
 880
 881         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 882                 goto drop;
 883
 884         skb_tx_timestamp(skb);
 885
 886         /* Orphan the skb - required as we might hang on to it
 887          * for indefinite time.
 888          */
 889         skb_orphan(skb);
 890
 891         nf_reset(skb);
 892
 893         if (skb_array_produce(&tfile->tx_array, skb))
 894                 goto drop;
 895
 896         /* Notify and wake up reader process */
 897         if (tfile->flags & TUN_FASYNC)
 898                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
 899         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 900
 901         rcu_read_unlock();
 902         return NETDEV_TX_OK;
 903
 904 drop:
 905         this_cpu_inc(tun->pcpu_stats->tx_dropped);
 906         skb_tx_error(skb);
 907         kfree_skb(skb);
 908         rcu_read_unlock();
 909         return NET_XMIT_DROP;
 910 }
 911
 912 static void tun_net_mclist(struct net_device *dev)
 913 {
 914         /*
 915          * This callback is supposed to deal with mc filter in
 916          * _rx_ path and has nothing to do with the _tx_ path.
 917          * In rx path we always accept everything userspace gives us.
 918          */
 919 }
 920
 921 static netdev_features_t tun_net_fix_features(struct net_device *dev,
 922         netdev_features_t features)
 923 {
 924         struct tun_struct *tun = netdev_priv(dev);
 925
 926         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 927 }
 928 #ifdef CONFIG_NET_POLL_CONTROLLER
 929 static void tun_poll_controller(struct net_device *dev)
 930 {
 931         /*
 932          * Tun only receives frames when:
 933          * 1) the char device endpoint gets data from user space
 934          * 2) the tun socket gets a sendmsg call from user space
 935          * Since both of those are synchronous operations, we are guaranteed
 936          * never to have pending data when we poll for it
 937          * so there is nothing to do here but return.
 938          * We need this though so netpoll recognizes us as an interface that
 939          * supports polling, which enables bridge devices in virt setups to
 940          * still use netconsole
 941          */
 942         return;
 943 }
 944 #endif
 945
 946 static void tun_set_headroom(struct net_device *dev, int new_hr)
 947 {
 948         struct tun_struct *tun = netdev_priv(dev);
 949
 950         if (new_hr < NET_SKB_PAD)
 951                 new_hr = NET_SKB_PAD;
 952
 953         tun->align = new_hr;
 954 }
 955
 956 static struct rtnl_link_stats64 *
 957 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 958 {
 959         u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
 960         struct tun_struct *tun = netdev_priv(dev);
 961         struct tun_pcpu_stats *p;
 962         int i;
 963
 964         for_each_possible_cpu(i) {
 965                 u64 rxpackets, rxbytes, txpackets, txbytes;
 966                 unsigned int start;
 967
 968                 p = per_cpu_ptr(tun->pcpu_stats, i);
 969                 do {
 970                         start = u64_stats_fetch_begin(&p->syncp);
 971                         rxpackets       = p->rx_packets;
 972                         rxbytes         = p->rx_bytes;
 973                         txpackets       = p->tx_packets;
 974                         txbytes         = p->tx_bytes;
 975                 } while (u64_stats_fetch_retry(&p->syncp, start));
 976
 977                 stats->rx_packets       += rxpackets;
 978                 stats->rx_bytes         += rxbytes;
 979                 stats->tx_packets       += txpackets;
 980                 stats->tx_bytes         += txbytes;
 981
 982                 /* u32 counters */
 983                 rx_dropped      += p->rx_dropped;
 984                 rx_frame_errors += p->rx_frame_errors;
 985                 tx_dropped      += p->tx_dropped;
 986         }
 987         stats->rx_dropped  = rx_dropped;
 988         stats->rx_frame_errors = rx_frame_errors;
 989         stats->tx_dropped = tx_dropped;
 990         return stats;
 991 }
 992
 993 static const struct net_device_ops tun_netdev_ops = {
 994         .ndo_uninit             = tun_net_uninit,
 995         .ndo_open               = tun_net_open,
 996         .ndo_stop               = tun_net_close,
 997         .ndo_start_xmit         = tun_net_xmit,
 998         .ndo_fix_features       = tun_net_fix_features,
 999         .ndo_select_queue       = tun_select_queue,
1000 #ifdef CONFIG_NET_POLL_CONTROLLER
1001         .ndo_poll_controller    = tun_poll_controller,
1002 #endif
1003         .ndo_set_rx_headroom    = tun_set_headroom,
1004         .ndo_get_stats64        = tun_net_get_stats64,
1005 };
1006
1007 static const struct net_device_ops tap_netdev_ops = {
1008         .ndo_uninit             = tun_net_uninit,
1009         .ndo_open               = tun_net_open,
1010         .ndo_stop               = tun_net_close,
1011         .ndo_start_xmit         = tun_net_xmit,
1012         .ndo_fix_features       = tun_net_fix_features,
1013         .ndo_set_rx_mode        = tun_net_mclist,
1014         .ndo_set_mac_address    = eth_mac_addr,
1015         .ndo_validate_addr      = eth_validate_addr,
1016         .ndo_select_queue       = tun_select_queue,
1017 #ifdef CONFIG_NET_POLL_CONTROLLER
1018         .ndo_poll_controller    = tun_poll_controller,
1019 #endif
1020         .ndo_features_check     = passthru_features_check,
1021         .ndo_set_rx_headroom    = tun_set_headroom,
1022         .ndo_get_stats64        = tun_net_get_stats64,
1023 };
1024
1025 static void tun_flow_init(struct tun_struct *tun)
1026 {
1027         int i;
1028
1029         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1030                 INIT_HLIST_HEAD(&tun->flows[i]);
1031
1032         tun->ageing_time = TUN_FLOW_EXPIRE;
1033         setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
1034         mod_timer(&tun->flow_gc_timer,
1035                   round_jiffies_up(jiffies + tun->ageing_time));
1036 }
1037
1038 static void tun_flow_uninit(struct tun_struct *tun)
1039 {
1040         del_timer_sync(&tun->flow_gc_timer);
1041         tun_flow_flush(tun);
1042 }
1043
1044 #define MIN_MTU 68
1045 #define MAX_MTU 65535
1046
1047 /* Initialize net device. */
1048 static void tun_net_init(struct net_device *dev)
1049 {
1050         struct tun_struct *tun = netdev_priv(dev);
1051
1052         switch (tun->flags & TUN_TYPE_MASK) {
1053         case IFF_TUN:
1054                 dev->netdev_ops = &tun_netdev_ops;
1055
1056                 /* Point-to-Point TUN Device */
1057                 dev->hard_header_len = 0;
1058                 dev->addr_len = 0;
1059                 dev->mtu = 1500;
1060
1061                 /* Zero header length */
1062                 dev->type = ARPHRD_NONE;
1063                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1064                 break;
1065
1066         case IFF_TAP:
1067                 dev->netdev_ops = &tap_netdev_ops;
1068                 /* Ethernet TAP Device */
1069                 ether_setup(dev);
1070                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1071                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1072
1073                 eth_hw_addr_random(dev);
1074
1075                 break;
1076         }
1077
1078         dev->min_mtu = MIN_MTU;
1079         dev->max_mtu = MAX_MTU - dev->hard_header_len;
1080 }
1081
1082 /* Character device part */
1083
1084 /* Poll */
1085 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1086 {
1087         struct tun_file *tfile = file->private_data;
1088         struct tun_struct *tun = __tun_get(tfile);
1089         struct sock *sk;
1090         unsigned int mask = 0;
1091
1092         if (!tun)
1093                 return POLLERR;
1094
1095         sk = tfile->socket.sk;
1096
1097         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1098
1099         poll_wait(file, sk_sleep(sk), wait);
1100
1101         if (!skb_array_empty(&tfile->tx_array))
1102                 mask |= POLLIN | POLLRDNORM;
1103
1104         if (sock_writeable(sk) ||
1105             (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1106              sock_writeable(sk)))
1107                 mask |= POLLOUT | POLLWRNORM;
1108
1109         if (tun->dev->reg_state != NETREG_REGISTERED)
1110                 mask = POLLERR;
1111
1112         tun_put(tun);
1113         return mask;
1114 }
1115
1116 /* prepad is the amount to reserve at front.  len is length after that.
1117  * linear is a hint as to how much to copy (usually headers). */
1118 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1119                                      size_t prepad, size_t len,
1120                                      size_t linear, int noblock)
1121 {
1122         struct sock *sk = tfile->socket.sk;
1123         struct sk_buff *skb;
1124         int err;
1125
1126         /* Under a page?  Don't bother with paged skb. */
1127         if (prepad + len < PAGE_SIZE || !linear)
1128                 linear = len;
1129
1130         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1131                                    &err, 0);
1132         if (!skb)
1133                 return ERR_PTR(err);
1134
1135         skb_reserve(skb, prepad);
1136         skb_put(skb, linear);
1137         skb->data_len = len - linear;
1138         skb->len += len - linear;
1139
1140         return skb;
1141 }
1142
1143 /* Get packet from user space buffer */
1144 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1145                             void *msg_control, struct iov_iter *from,
1146                             int noblock)
1147 {
1148         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1149         struct sk_buff *skb;
1150         size_t total_len = iov_iter_count(from);
1151         size_t len = total_len, align = tun->align, linear;
1152         struct virtio_net_hdr gso = { 0 };
1153         struct tun_pcpu_stats *stats;
1154         int good_linear;
1155         int copylen;
1156         bool zerocopy = false;
1157         int err;
1158         u32 rxhash;
1159         ssize_t n;
1160
1161         if (!(tun->dev->flags & IFF_UP))
1162                 return -EIO;
1163
1164         if (!(tun->flags & IFF_NO_PI)) {
1165                 if (len < sizeof(pi))
1166                         return -EINVAL;
1167                 len -= sizeof(pi);
1168
1169                 n = copy_from_iter(&pi, sizeof(pi), from);
1170                 if (n != sizeof(pi))
1171                         return -EFAULT;
1172         }
1173
1174         if (tun->flags & IFF_VNET_HDR) {
1175                 if (len < tun->vnet_hdr_sz)
1176                         return -EINVAL;
1177                 len -= tun->vnet_hdr_sz;
1178
1179                 n = copy_from_iter(&gso, sizeof(gso), from);
1180                 if (n != sizeof(gso))
1181                         return -EFAULT;
1182
1183                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1184                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1185                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1186
1187                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1188                         return -EINVAL;
1189                 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso));
1190         }
1191
1192         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1193                 align += NET_IP_ALIGN;
1194                 if (unlikely(len < ETH_HLEN ||
1195                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1196                         return -EINVAL;
1197         }
1198
1199         good_linear = SKB_MAX_HEAD(align);
1200
1201         if (msg_control) {
1202                 struct iov_iter i = *from;
1203
1204                 /* There are 256 bytes to be copied in skb, so there is
1205                  * enough room for skb expand head in case it is used.
1206                  * The rest of the buffer is mapped from userspace.
1207                  */
1208                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1209                 if (copylen > good_linear)
1210                         copylen = good_linear;
1211                 linear = copylen;
1212                 iov_iter_advance(&i, copylen);
1213                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1214                         zerocopy = true;
1215         }
1216
1217         if (!zerocopy) {
1218                 copylen = len;
1219                 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1220                         linear = good_linear;
1221                 else
1222                         linear = tun16_to_cpu(tun, gso.hdr_len);
1223         }
1224
1225         skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1226         if (IS_ERR(skb)) {
1227                 if (PTR_ERR(skb) != -EAGAIN)
1228                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1229                 return PTR_ERR(skb);
1230         }
1231
1232         if (zerocopy)
1233                 err = zerocopy_sg_from_iter(skb, from);
1234         else
1235                 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1236
1237         if (err) {
1238                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1239                 kfree_skb(skb);
1240                 return -EFAULT;
1241         }
1242
1243         if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1244                 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1245                 kfree_skb(skb);
1246                 return -EINVAL;
1247         }
1248
1249         switch (tun->flags & TUN_TYPE_MASK) {
1250         case IFF_TUN:
1251                 if (tun->flags & IFF_NO_PI) {
1252                         switch (skb->data[0] & 0xf0) {
1253                         case 0x40:
1254                                 pi.proto = htons(ETH_P_IP);
1255                                 break;
1256                         case 0x60:
1257                                 pi.proto = htons(ETH_P_IPV6);
1258                                 break;
1259                         default:
1260                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1261                                 kfree_skb(skb);
1262                                 return -EINVAL;
1263                         }
1264                 }
1265
1266                 skb_reset_mac_header(skb);
1267                 skb->protocol = pi.proto;
1268                 skb->dev = tun->dev;
1269                 break;
1270         case IFF_TAP:
1271                 skb->protocol = eth_type_trans(skb, tun->dev);
1272                 break;
1273         }
1274
1275         /* copy skb_ubuf_info for callback when skb has no error */
1276         if (zerocopy) {
1277                 skb_shinfo(skb)->destructor_arg = msg_control;
1278                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1279                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1280         } else if (msg_control) {
1281                 struct ubuf_info *uarg = msg_control;
1282                 uarg->callback(uarg, false);
1283         }
1284
1285         skb_reset_network_header(skb);
1286         skb_probe_transport_header(skb, 0);
1287
1288         rxhash = skb_get_hash(skb);
1289 #ifndef CONFIG_4KSTACKS
1290         local_bh_disable();
1291         netif_receive_skb(skb);
1292         local_bh_enable();
1293 #else
1294         netif_rx_ni(skb);
1295 #endif
1296
1297         stats = get_cpu_ptr(tun->pcpu_stats);
1298         u64_stats_update_begin(&stats->syncp);
1299         stats->rx_packets++;
1300         stats->rx_bytes += len;
1301         u64_stats_update_end(&stats->syncp);
1302         put_cpu_ptr(stats);
1303
1304         tun_flow_update(tun, rxhash, tfile);
1305         return total_len;
1306 }
1307
1308 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1309 {
1310         struct file *file = iocb->ki_filp;
1311         struct tun_struct *tun = tun_get(file);
1312         struct tun_file *tfile = file->private_data;
1313         ssize_t result;
1314
1315         if (!tun)
1316                 return -EBADFD;
1317
1318         result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);
1319
1320         tun_put(tun);
1321         return result;
1322 }
1323
1324 /* Put packet to the user space buffer */
1325 static ssize_t tun_put_user(struct tun_struct *tun,
1326                             struct tun_file *tfile,
1327                             struct sk_buff *skb,
1328                             struct iov_iter *iter)
1329 {
1330         struct tun_pi pi = { 0, skb->protocol };
1331         struct tun_pcpu_stats *stats;
1332         ssize_t total;
1333         int vlan_offset = 0;
1334         int vlan_hlen = 0;
1335         int vnet_hdr_sz = 0;
1336
1337         if (skb_vlan_tag_present(skb))
1338                 vlan_hlen = VLAN_HLEN;
1339
1340         if (tun->flags & IFF_VNET_HDR)
1341                 vnet_hdr_sz = tun->vnet_hdr_sz;
1342
1343         total = skb->len + vlan_hlen + vnet_hdr_sz;
1344
1345         if (!(tun->flags & IFF_NO_PI)) {
1346                 if (iov_iter_count(iter) < sizeof(pi))
1347                         return -EINVAL;
1348
1349                 total += sizeof(pi);
1350                 if (iov_iter_count(iter) < total) {
1351                         /* Packet will be striped */
1352                         pi.flags |= TUN_PKT_STRIP;
1353                 }
1354
1355                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1356                         return -EFAULT;
1357         }
1358
1359         if (vnet_hdr_sz) {
1360                 struct virtio_net_hdr gso;
1361
1362                 if (iov_iter_count(iter) < vnet_hdr_sz)
1363                         return -EINVAL;
1364
1365                 if (virtio_net_hdr_from_skb(skb, &gso,
1366                                             tun_is_little_endian(tun))) {
1367                         struct skb_shared_info *sinfo = skb_shinfo(skb);
1368                         pr_err("unexpected GSO type: "
1369                                "0x%x, gso_size %d, hdr_len %d\n",
1370                                sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1371                                tun16_to_cpu(tun, gso.hdr_len));
1372                         print_hex_dump(KERN_ERR, "tun: ",
1373                                        DUMP_PREFIX_NONE,
1374                                        16, 1, skb->head,
1375                                        min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1376                         WARN_ON_ONCE(1);
1377                         return -EINVAL;
1378                 }
1379
1380                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1381                         return -EFAULT;
1382
1383                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1384         }
1385
1386         if (vlan_hlen) {
1387                 int ret;
1388                 struct {
1389                         __be16 h_vlan_proto;
1390                         __be16 h_vlan_TCI;
1391                 } veth;
1392
1393                 veth.h_vlan_proto = skb->vlan_proto;
1394                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1395
1396                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1397
1398                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1399                 if (ret || !iov_iter_count(iter))
1400                         goto done;
1401
1402                 ret = copy_to_iter(&veth, sizeof(veth), iter);
1403                 if (ret != sizeof(veth) || !iov_iter_count(iter))
1404                         goto done;
1405         }
1406
1407         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1408
1409 done:
1410         /* caller is in process context, */
1411         stats = get_cpu_ptr(tun->pcpu_stats);
1412         u64_stats_update_begin(&stats->syncp);
1413         stats->tx_packets++;
1414         stats->tx_bytes += skb->len + vlan_hlen;
1415         u64_stats_update_end(&stats->syncp);
1416         put_cpu_ptr(tun->pcpu_stats);
1417
1418         return total;
1419 }
1420
1421 static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
1422                                      int *err)
1423 {
1424         DECLARE_WAITQUEUE(wait, current);
1425         struct sk_buff *skb = NULL;
1426         int error = 0;
1427
1428         skb = skb_array_consume(&tfile->tx_array);
1429         if (skb)
1430                 goto out;
1431         if (noblock) {
1432                 error = -EAGAIN;
1433                 goto out;
1434         }
1435
1436         add_wait_queue(&tfile->wq.wait, &wait);
1437         current->state = TASK_INTERRUPTIBLE;
1438
1439         while (1) {
1440                 skb = skb_array_consume(&tfile->tx_array);
1441                 if (skb)
1442                         break;
1443                 if (signal_pending(current)) {
1444                         error = -ERESTARTSYS;
1445                         break;
1446                 }
1447                 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
1448                         error = -EFAULT;
1449                         break;
1450                 }
1451
1452                 schedule();
1453         }
1454
1455         current->state = TASK_RUNNING;
1456         remove_wait_queue(&tfile->wq.wait, &wait);
1457
1458 out:
1459         *err = error;
1460         return skb;
1461 }
1462
1463 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1464                            struct iov_iter *to,
1465                            int noblock)
1466 {
1467         struct sk_buff *skb;
1468         ssize_t ret;
1469         int err;
1470
1471         tun_debug(KERN_INFO, tun, "tun_do_read\n");
1472
1473         if (!iov_iter_count(to))
1474                 return 0;
1475
1476         /* Read frames from ring */
1477         skb = tun_ring_recv(tfile, noblock, &err);
1478         if (!skb)
1479                 return err;
1480
1481         ret = tun_put_user(tun, tfile, skb, to);
1482         if (unlikely(ret < 0))
1483                 kfree_skb(skb);
1484         else
1485                 consume_skb(skb);
1486
1487         return ret;
1488 }
1489
1490 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1491 {
1492         struct file *file = iocb->ki_filp;
1493         struct tun_file *tfile = file->private_data;
1494         struct tun_struct *tun = __tun_get(tfile);
1495         ssize_t len = iov_iter_count(to), ret;
1496
1497         if (!tun)
1498                 return -EBADFD;
1499         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
1500         ret = min_t(ssize_t, ret, len);
1501         if (ret > 0)
1502                 iocb->ki_pos = ret;
1503         tun_put(tun);
1504         return ret;
1505 }
1506
1507 static void tun_free_netdev(struct net_device *dev)
1508 {
1509         struct tun_struct *tun = netdev_priv(dev);
1510
1511         BUG_ON(!(list_empty(&tun->disabled)));
1512         free_percpu(tun->pcpu_stats);
1513         tun_flow_uninit(tun);
1514         security_tun_dev_free_security(tun->security);
1515         free_netdev(dev);
1516 }
1517
1518 static void tun_setup(struct net_device *dev)
1519 {
1520         struct tun_struct *tun = netdev_priv(dev);
1521
1522         tun->owner = INVALID_UID;
1523         tun->group = INVALID_GID;
1524
1525         dev->ethtool_ops = &tun_ethtool_ops;
1526         dev->destructor = tun_free_netdev;
1527         /* We prefer our own queue length */
1528         dev->tx_queue_len = TUN_READQ_SIZE;
1529 }
1530
1531 /* Trivial set of netlink ops to allow deleting tun or tap
1532  * device with netlink.
1533  */
1534 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1535 {
1536         return -EINVAL;
1537 }
1538
1539 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1540         .kind           = DRV_NAME,
1541         .priv_size      = sizeof(struct tun_struct),
1542         .setup          = tun_setup,
1543         .validate       = tun_validate,
1544 };
1545
1546 static void tun_sock_write_space(struct sock *sk)
1547 {
1548         struct tun_file *tfile;
1549         wait_queue_head_t *wqueue;
1550
1551         if (!sock_writeable(sk))
1552                 return;
1553
1554         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
1555                 return;
1556
1557         wqueue = sk_sleep(sk);
1558         if (wqueue && waitqueue_active(wqueue))
1559                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1560                                                 POLLWRNORM | POLLWRBAND);
1561
1562         tfile = container_of(sk, struct tun_file, sk);
1563         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1564 }
1565
1566 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1567 {
1568         int ret;
1569         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1570         struct tun_struct *tun = __tun_get(tfile);
1571
1572         if (!tun)
1573                 return -EBADFD;
1574
1575         ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1576                            m->msg_flags & MSG_DONTWAIT);
1577         tun_put(tun);
1578         return ret;
1579 }
1580
1581 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1582                        int flags)
1583 {
1584         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1585         struct tun_struct *tun = __tun_get(tfile);
1586         int ret;
1587
1588         if (!tun)
1589                 return -EBADFD;
1590
1591         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1592                 ret = -EINVAL;
1593                 goto out;
1594         }
1595         if (flags & MSG_ERRQUEUE) {
1596                 ret = sock_recv_errqueue(sock->sk, m, total_len,
1597                                          SOL_PACKET, TUN_TX_TIMESTAMP);
1598                 goto out;
1599         }
1600         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1601         if (ret > (ssize_t)total_len) {
1602                 m->msg_flags |= MSG_TRUNC;
1603                 ret = flags & MSG_TRUNC ? ret : total_len;
1604         }
1605 out:
1606         tun_put(tun);
1607         return ret;
1608 }
1609
1610 static int tun_peek_len(struct socket *sock)
1611 {
1612         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1613         struct tun_struct *tun;
1614         int ret = 0;
1615
1616         tun = __tun_get(tfile);
1617         if (!tun)
1618                 return 0;
1619
1620         ret = skb_array_peek_len(&tfile->tx_array);
1621         tun_put(tun);
1622
1623         return ret;
1624 }
1625
1626 /* Ops structure to mimic raw sockets with tun */
1627 static const struct proto_ops tun_socket_ops = {
1628         .peek_len = tun_peek_len,
1629         .sendmsg = tun_sendmsg,
1630         .recvmsg = tun_recvmsg,
1631 };
1632
1633 static struct proto tun_proto = {
1634         .name           = "tun",
1635         .owner          = THIS_MODULE,
1636         .obj_size       = sizeof(struct tun_file),
1637 };
1638
1639 static int tun_flags(struct tun_struct *tun)
1640 {
1641         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1642 }
1643
1644 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1645                               char *buf)
1646 {
1647         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1648         return sprintf(buf, "0x%x\n", tun_flags(tun));
1649 }
1650
1651 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1652                               char *buf)
1653 {
1654         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1655         return uid_valid(tun->owner)?
1656                 sprintf(buf, "%u\n",
1657                         from_kuid_munged(current_user_ns(), tun->owner)):
1658                 sprintf(buf, "-1\n");
1659 }
1660
1661 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1662                               char *buf)
1663 {
1664         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1665         return gid_valid(tun->group) ?
1666                 sprintf(buf, "%u\n",
1667                         from_kgid_munged(current_user_ns(), tun->group)):
1668                 sprintf(buf, "-1\n");
1669 }
1670
1671 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1672 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1673 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1674
1675 static struct attribute *tun_dev_attrs[] = {
1676         &dev_attr_tun_flags.attr,
1677         &dev_attr_owner.attr,
1678         &dev_attr_group.attr,
1679         NULL
1680 };
1681
1682 static const struct attribute_group tun_attr_group = {
1683         .attrs = tun_dev_attrs
1684 };
1685
1686 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1687 {
1688         struct tun_struct *tun;
1689         struct tun_file *tfile = file->private_data;
1690         struct net_device *dev;
1691         int err;
1692
1693         if (tfile->detached)
1694                 return -EINVAL;
1695
1696         dev = __dev_get_by_name(net, ifr->ifr_name);
1697         if (dev) {
1698                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1699                         return -EBUSY;
1700                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1701                         tun = netdev_priv(dev);
1702                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1703                         tun = netdev_priv(dev);
1704                 else
1705                         return -EINVAL;
1706
1707                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1708                     !!(tun->flags & IFF_MULTI_QUEUE))
1709                         return -EINVAL;
1710
1711                 if (tun_not_capable(tun))
1712                         return -EPERM;
1713                 err = security_tun_dev_open(tun->security);
1714                 if (err < 0)
1715                         return err;
1716
1717                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1718                 if (err < 0)
1719                         return err;
1720
1721                 if (tun->flags & IFF_MULTI_QUEUE &&
1722                     (tun->numqueues + tun->numdisabled > 1)) {
1723                         /* One or more queue has already been attached, no need
1724                          * to initialize the device again.
1725                          */
1726                         return 0;
1727                 }
1728         }
1729         else {
1730                 char *name;
1731                 unsigned long flags = 0;
1732                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1733                              MAX_TAP_QUEUES : 1;
1734
1735                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1736                         return -EPERM;
1737                 err = security_tun_dev_create();
1738                 if (err < 0)
1739                         return err;
1740
1741                 /* Set dev type */
1742                 if (ifr->ifr_flags & IFF_TUN) {
1743                         /* TUN device */
1744                         flags |= IFF_TUN;
1745                         name = "tun%d";
1746                 } else if (ifr->ifr_flags & IFF_TAP) {
1747                         /* TAP device */
1748                         flags |= IFF_TAP;
1749                         name = "tap%d";
1750                 } else
1751                         return -EINVAL;
1752
1753                 if (*ifr->ifr_name)
1754                         name = ifr->ifr_name;
1755
1756                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1757                                        NET_NAME_UNKNOWN, tun_setup, queues,
1758                                        queues);
1759
1760                 if (!dev)
1761                         return -ENOMEM;
1762
1763                 dev_net_set(dev, net);
1764                 dev->rtnl_link_ops = &tun_link_ops;
1765                 dev->ifindex = tfile->ifindex;
1766                 dev->sysfs_groups[0] = &tun_attr_group;
1767
1768                 tun = netdev_priv(dev);
1769                 tun->dev = dev;
1770                 tun->flags = flags;
1771                 tun->txflt.count = 0;
1772                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1773
1774                 tun->align = NET_SKB_PAD;
1775                 tun->filter_attached = false;
1776                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1777
1778                 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
1779                 if (!tun->pcpu_stats) {
1780                         err = -ENOMEM;
1781                         goto err_free_dev;
1782                 }
1783
1784                 spin_lock_init(&tun->lock);
1785
1786                 err = security_tun_dev_alloc_security(&tun->security);
1787                 if (err < 0)
1788                         goto err_free_stat;
1789
1790                 tun_net_init(dev);
1791                 tun_flow_init(tun);
1792
1793                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1794                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1795                                    NETIF_F_HW_VLAN_STAG_TX;
1796                 dev->features = dev->hw_features | NETIF_F_LLTX;
1797                 dev->vlan_features = dev->features &
1798                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
1799                                        NETIF_F_HW_VLAN_STAG_TX);
1800
1801                 INIT_LIST_HEAD(&tun->disabled);
1802                 err = tun_attach(tun, file, false);
1803                 if (err < 0)
1804                         goto err_free_flow;
1805
1806                 err = register_netdevice(tun->dev);
1807                 if (err < 0)
1808                         goto err_detach;
1809         }
1810
1811         netif_carrier_on(tun->dev);
1812
1813         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1814
1815         tun->flags = (tun->flags & ~TUN_FEATURES) |
1816                 (ifr->ifr_flags & TUN_FEATURES);
1817
1818         /* Make sure persistent devices do not get stuck in
1819          * xoff state.
1820          */
1821         if (netif_running(tun->dev))
1822                 netif_tx_wake_all_queues(tun->dev);
1823
1824         strcpy(ifr->ifr_name, tun->dev->name);
1825         return 0;
1826
1827 err_detach:
1828         tun_detach_all(dev);
1829 err_free_flow:
1830         tun_flow_uninit(tun);
1831         security_tun_dev_free_security(tun->security);
1832 err_free_stat:
1833         free_percpu(tun->pcpu_stats);
1834 err_free_dev:
1835         free_netdev(dev);
1836         return err;
1837 }
1838
1839 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1840                        struct ifreq *ifr)
1841 {
1842         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1843
1844         strcpy(ifr->ifr_name, tun->dev->name);
1845
1846         ifr->ifr_flags = tun_flags(tun);
1847
1848 }
1849
1850 /* This is like a cut-down ethtool ops, except done via tun fd so no
1851  * privs required. */
1852 static int set_offload(struct tun_struct *tun, unsigned long arg)
1853 {
1854         netdev_features_t features = 0;
1855
1856         if (arg & TUN_F_CSUM) {
1857                 features |= NETIF_F_HW_CSUM;
1858                 arg &= ~TUN_F_CSUM;
1859
1860                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1861                         if (arg & TUN_F_TSO_ECN) {
1862                                 features |= NETIF_F_TSO_ECN;
1863                                 arg &= ~TUN_F_TSO_ECN;
1864                         }
1865                         if (arg & TUN_F_TSO4)
1866                                 features |= NETIF_F_TSO;
1867                         if (arg & TUN_F_TSO6)
1868                                 features |= NETIF_F_TSO6;
1869                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1870                 }
1871
1872                 if (arg & TUN_F_UFO) {
1873                         features |= NETIF_F_UFO;
1874                         arg &= ~TUN_F_UFO;
1875                 }
1876         }
1877
1878         /* This gives the user a way to test for new features in future by
1879          * trying to set them. */
1880         if (arg)
1881                 return -EINVAL;
1882
1883         tun->set_features = features;
1884         netdev_update_features(tun->dev);
1885
1886         return 0;
1887 }
1888
1889 static void tun_detach_filter(struct tun_struct *tun, int n)
1890 {
1891         int i;
1892         struct tun_file *tfile;
1893
1894         for (i = 0; i < n; i++) {
1895                 tfile = rtnl_dereference(tun->tfiles[i]);
1896                 lock_sock(tfile->socket.sk);
1897                 sk_detach_filter(tfile->socket.sk);
1898                 release_sock(tfile->socket.sk);
1899         }
1900
1901         tun->filter_attached = false;
1902 }
1903
1904 static int tun_attach_filter(struct tun_struct *tun)
1905 {
1906         int i, ret = 0;
1907         struct tun_file *tfile;
1908
1909         for (i = 0; i < tun->numqueues; i++) {
1910                 tfile = rtnl_dereference(tun->tfiles[i]);
1911                 lock_sock(tfile->socket.sk);
1912                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1913                 release_sock(tfile->socket.sk);
1914                 if (ret) {
1915                         tun_detach_filter(tun, i);
1916                         return ret;
1917                 }
1918         }
1919
1920         tun->filter_attached = true;
1921         return ret;
1922 }
1923
1924 static void tun_set_sndbuf(struct tun_struct *tun)
1925 {
1926         struct tun_file *tfile;
1927         int i;
1928
1929         for (i = 0; i < tun->numqueues; i++) {
1930                 tfile = rtnl_dereference(tun->tfiles[i]);
1931                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1932         }
1933 }
1934
1935 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1936 {
1937         struct tun_file *tfile = file->private_data;
1938         struct tun_struct *tun;
1939         int ret = 0;
1940
1941         rtnl_lock();
1942
1943         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1944                 tun = tfile->detached;
1945                 if (!tun) {
1946                         ret = -EINVAL;
1947                         goto unlock;
1948                 }
1949                 ret = security_tun_dev_attach_queue(tun->security);
1950                 if (ret < 0)
1951                         goto unlock;
1952                 ret = tun_attach(tun, file, false);
1953         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1954                 tun = rtnl_dereference(tfile->tun);
1955                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1956                         ret = -EINVAL;
1957                 else
1958                         __tun_detach(tfile, false);
1959         } else
1960                 ret = -EINVAL;
1961
1962 unlock:
1963         rtnl_unlock();
1964         return ret;
1965 }
1966
1967 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1968                             unsigned long arg, int ifreq_len)
1969 {
1970         struct tun_file *tfile = file->private_data;
1971         struct tun_struct *tun;
1972         void __user* argp = (void __user*)arg;
1973         struct ifreq ifr;
1974         kuid_t owner;
1975         kgid_t group;
1976         int sndbuf;
1977         int vnet_hdr_sz;
1978         unsigned int ifindex;
1979         int le;
1980         int ret;
1981
1982         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) {
1983                 if (copy_from_user(&ifr, argp, ifreq_len))
1984                         return -EFAULT;
1985         } else {
1986                 memset(&ifr, 0, sizeof(ifr));
1987         }
1988         if (cmd == TUNGETFEATURES) {
1989                 /* Currently this just means: "what IFF flags are valid?".
1990                  * This is needed because we never checked for invalid flags on
1991                  * TUNSETIFF.
1992                  */
1993                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
1994                                 (unsigned int __user*)argp);
1995         } else if (cmd == TUNSETQUEUE)
1996                 return tun_set_queue(file, &ifr);
1997
1998         ret = 0;
1999         rtnl_lock();
2000
2001         tun = __tun_get(tfile);
2002         if (cmd == TUNSETIFF) {
2003                 ret = -EEXIST;
2004                 if (tun)
2005                         goto unlock;
2006
2007                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2008
2009                 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
2010
2011                 if (ret)
2012                         goto unlock;
2013
2014                 if (copy_to_user(argp, &ifr, ifreq_len))
2015                         ret = -EFAULT;
2016                 goto unlock;
2017         }
2018         if (cmd == TUNSETIFINDEX) {
2019                 ret = -EPERM;
2020                 if (tun)
2021                         goto unlock;
2022
2023                 ret = -EFAULT;
2024                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2025                         goto unlock;
2026
2027                 ret = 0;
2028                 tfile->ifindex = ifindex;
2029                 goto unlock;
2030         }
2031
2032         ret = -EBADFD;
2033         if (!tun)
2034                 goto unlock;
2035
2036         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2037
2038         ret = 0;
2039         switch (cmd) {
2040         case TUNGETIFF:
2041                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2042
2043                 if (tfile->detached)
2044                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
2045                 if (!tfile->socket.sk->sk_filter)
2046                         ifr.ifr_flags |= IFF_NOFILTER;
2047
2048                 if (copy_to_user(argp, &ifr, ifreq_len))
2049                         ret = -EFAULT;
2050                 break;
2051
2052         case TUNSETNOCSUM:
2053                 /* Disable/Enable checksum */
2054
2055                 /* [unimplemented] */
2056                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2057                           arg ? "disabled" : "enabled");
2058                 break;
2059
2060         case TUNSETPERSIST:
2061                 /* Disable/Enable persist mode. Keep an extra reference to the
2062                  * module to prevent the module being unprobed.
2063                  */
2064                 if (arg && !(tun->flags & IFF_PERSIST)) {
2065                         tun->flags |= IFF_PERSIST;
2066                         __module_get(THIS_MODULE);
2067                 }
2068                 if (!arg && (tun->flags & IFF_PERSIST)) {
2069                         tun->flags &= ~IFF_PERSIST;
2070                         module_put(THIS_MODULE);
2071                 }
2072
2073                 tun_debug(KERN_INFO, tun, "persist %s\n",
2074                           arg ? "enabled" : "disabled");
2075                 break;
2076
2077         case TUNSETOWNER:
2078                 /* Set owner of the device */
2079                 owner = make_kuid(current_user_ns(), arg);
2080                 if (!uid_valid(owner)) {
2081                         ret = -EINVAL;
2082                         break;
2083                 }
2084                 tun->owner = owner;
2085                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2086                           from_kuid(&init_user_ns, tun->owner));
2087                 break;
2088
2089         case TUNSETGROUP:
2090                 /* Set group of the device */
2091                 group = make_kgid(current_user_ns(), arg);
2092                 if (!gid_valid(group)) {
2093                         ret = -EINVAL;
2094                         break;
2095                 }
2096                 tun->group = group;
2097                 tun_debug(KERN_INFO, tun, "group set to %u\n",
2098                           from_kgid(&init_user_ns, tun->group));
2099                 break;
2100
2101         case TUNSETLINK:
2102                 /* Only allow setting the type when the interface is down */
2103                 if (tun->dev->flags & IFF_UP) {
2104                         tun_debug(KERN_INFO, tun,
2105                                   "Linktype set failed because interface is up\n");
2106                         ret = -EBUSY;
2107                 } else {
2108                         tun->dev->type = (int) arg;
2109                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2110                                   tun->dev->type);
2111                         ret = 0;
2112                 }
2113                 break;
2114
2115 #ifdef TUN_DEBUG
2116         case TUNSETDEBUG:
2117                 tun->debug = arg;
2118                 break;
2119 #endif
2120         case TUNSETOFFLOAD:
2121                 ret = set_offload(tun, arg);
2122                 break;
2123
2124         case TUNSETTXFILTER:
2125                 /* Can be set only for TAPs */
2126                 ret = -EINVAL;
2127                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2128                         break;
2129                 ret = update_filter(&tun->txflt, (void __user *)arg);
2130                 break;
2131
2132         case SIOCGIFHWADDR:
2133                 /* Get hw address */
2134                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2135                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2136                 if (copy_to_user(argp, &ifr, ifreq_len))
2137                         ret = -EFAULT;
2138                 break;
2139
2140         case SIOCSIFHWADDR:
2141                 /* Set hw address */
2142                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2143                           ifr.ifr_hwaddr.sa_data);
2144
2145                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2146                 break;
2147
2148         case TUNGETSNDBUF:
2149                 sndbuf = tfile->socket.sk->sk_sndbuf;
2150                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2151                         ret = -EFAULT;
2152                 break;
2153
2154         case TUNSETSNDBUF:
2155                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2156                         ret = -EFAULT;
2157                         break;
2158                 }
2159
2160                 tun->sndbuf = sndbuf;
2161                 tun_set_sndbuf(tun);
2162                 break;
2163
2164         case TUNGETVNETHDRSZ:
2165                 vnet_hdr_sz = tun->vnet_hdr_sz;
2166                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2167                         ret = -EFAULT;
2168                 break;
2169
2170         case TUNSETVNETHDRSZ:
2171                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2172                         ret = -EFAULT;
2173                         break;
2174                 }
2175                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2176                         ret = -EINVAL;
2177                         break;
2178                 }
2179
2180                 tun->vnet_hdr_sz = vnet_hdr_sz;
2181                 break;
2182
2183         case TUNGETVNETLE:
2184                 le = !!(tun->flags & TUN_VNET_LE);
2185                 if (put_user(le, (int __user *)argp))
2186                         ret = -EFAULT;
2187                 break;
2188
2189         case TUNSETVNETLE:
2190                 if (get_user(le, (int __user *)argp)) {
2191                         ret = -EFAULT;
2192                         break;
2193                 }
2194                 if (le)
2195                         tun->flags |= TUN_VNET_LE;
2196                 else
2197                         tun->flags &= ~TUN_VNET_LE;
2198                 break;
2199
2200         case TUNGETVNETBE:
2201                 ret = tun_get_vnet_be(tun, argp);
2202                 break;
2203
2204         case TUNSETVNETBE:
2205                 ret = tun_set_vnet_be(tun, argp);
2206                 break;
2207
2208         case TUNATTACHFILTER:
2209                 /* Can be set only for TAPs */
2210                 ret = -EINVAL;
2211                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2212                         break;
2213                 ret = -EFAULT;
2214                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2215                         break;
2216
2217                 ret = tun_attach_filter(tun);
2218                 break;
2219
2220         case TUNDETACHFILTER:
2221                 /* Can be set only for TAPs */
2222                 ret = -EINVAL;
2223                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2224                         break;
2225                 ret = 0;
2226                 tun_detach_filter(tun, tun->numqueues);
2227                 break;
2228
2229         case TUNGETFILTER:
2230                 ret = -EINVAL;
2231                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2232                         break;
2233                 ret = -EFAULT;
2234                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2235                         break;
2236                 ret = 0;
2237                 break;
2238
2239         default:
2240                 ret = -EINVAL;
2241                 break;
2242         }
2243
2244 unlock:
2245         rtnl_unlock();
2246         if (tun)
2247                 tun_put(tun);
2248         return ret;
2249 }
2250
2251 static long tun_chr_ioctl(struct file *file,
2252                           unsigned int cmd, unsigned long arg)
2253 {
2254         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2255 }
2256
2257 #ifdef CONFIG_COMPAT
2258 static long tun_chr_compat_ioctl(struct file *file,
2259                          unsigned int cmd, unsigned long arg)
2260 {
2261         switch (cmd) {
2262         case TUNSETIFF:
2263         case TUNGETIFF:
2264         case TUNSETTXFILTER:
2265         case TUNGETSNDBUF:
2266         case TUNSETSNDBUF:
2267         case SIOCGIFHWADDR:
2268         case SIOCSIFHWADDR:
2269                 arg = (unsigned long)compat_ptr(arg);
2270                 break;
2271         default:
2272                 arg = (compat_ulong_t)arg;
2273                 break;
2274         }
2275
2276         /*
2277          * compat_ifreq is shorter than ifreq, so we must not access beyond
2278          * the end of that structure. All fields that are used in this
2279          * driver are compatible though, we don't need to convert the
2280          * contents.
2281          */
2282         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2283 }
2284 #endif /* CONFIG_COMPAT */
2285
2286 static int tun_chr_fasync(int fd, struct file *file, int on)
2287 {
2288         struct tun_file *tfile = file->private_data;
2289         int ret;
2290
2291         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2292                 goto out;
2293
2294         if (on) {
2295                 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2296                 tfile->flags |= TUN_FASYNC;
2297         } else
2298                 tfile->flags &= ~TUN_FASYNC;
2299         ret = 0;
2300 out:
2301         return ret;
2302 }
2303
2304 static int tun_chr_open(struct inode *inode, struct file * file)
2305 {
2306         struct net *net = current->nsproxy->net_ns;
2307         struct tun_file *tfile;
2308
2309         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2310
2311         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2312                                             &tun_proto, 0);
2313         if (!tfile)
2314                 return -ENOMEM;
2315         RCU_INIT_POINTER(tfile->tun, NULL);
2316         tfile->flags = 0;
2317         tfile->ifindex = 0;
2318
2319         init_waitqueue_head(&tfile->wq.wait);
2320         RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2321
2322         tfile->socket.file = file;
2323         tfile->socket.ops = &tun_socket_ops;
2324
2325         sock_init_data(&tfile->socket, &tfile->sk);
2326
2327         tfile->sk.sk_write_space = tun_sock_write_space;
2328         tfile->sk.sk_sndbuf = INT_MAX;
2329
2330         file->private_data = tfile;
2331         INIT_LIST_HEAD(&tfile->next);
2332
2333         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2334
2335         return 0;
2336 }
2337
2338 static int tun_chr_close(struct inode *inode, struct file *file)
2339 {
2340         struct tun_file *tfile = file->private_data;
2341
2342         tun_detach(tfile, true);
2343
2344         return 0;
2345 }
2346
2347 #ifdef CONFIG_PROC_FS
2348 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2349 {
2350         struct tun_struct *tun;
2351         struct ifreq ifr;
2352
2353         memset(&ifr, 0, sizeof(ifr));
2354
2355         rtnl_lock();
2356         tun = tun_get(f);
2357         if (tun)
2358                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2359         rtnl_unlock();
2360
2361         if (tun)
2362                 tun_put(tun);
2363
2364         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2365 }
2366 #endif
2367
2368 static const struct file_operations tun_fops = {
2369         .owner  = THIS_MODULE,
2370         .llseek = no_llseek,
2371         .read_iter  = tun_chr_read_iter,
2372         .write_iter = tun_chr_write_iter,
2373         .poll   = tun_chr_poll,
2374         .unlocked_ioctl = tun_chr_ioctl,
2375 #ifdef CONFIG_COMPAT
2376         .compat_ioctl = tun_chr_compat_ioctl,
2377 #endif
2378         .open   = tun_chr_open,
2379         .release = tun_chr_close,
2380         .fasync = tun_chr_fasync,
2381 #ifdef CONFIG_PROC_FS
2382         .show_fdinfo = tun_chr_show_fdinfo,
2383 #endif
2384 };
2385
2386 static struct miscdevice tun_miscdev = {
2387         .minor = TUN_MINOR,
2388         .name = "tun",
2389         .nodename = "net/tun",
2390         .fops = &tun_fops,
2391 };
2392
2393 /* ethtool interface */
2394
2395 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2396 {
2397         cmd->supported          = 0;
2398         cmd->advertising        = 0;
2399         ethtool_cmd_speed_set(cmd, SPEED_10);
2400         cmd->duplex             = DUPLEX_FULL;
2401         cmd->port               = PORT_TP;
2402         cmd->phy_address        = 0;
2403         cmd->transceiver        = XCVR_INTERNAL;
2404         cmd->autoneg            = AUTONEG_DISABLE;
2405         cmd->maxtxpkt           = 0;
2406         cmd->maxrxpkt           = 0;
2407         return 0;
2408 }
2409
2410 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2411 {
2412         struct tun_struct *tun = netdev_priv(dev);
2413
2414         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2415         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2416
2417         switch (tun->flags & TUN_TYPE_MASK) {
2418         case IFF_TUN:
2419                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2420                 break;
2421         case IFF_TAP:
2422                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2423                 break;
2424         }
2425 }
2426
2427 static u32 tun_get_msglevel(struct net_device *dev)
2428 {
2429 #ifdef TUN_DEBUG
2430         struct tun_struct *tun = netdev_priv(dev);
2431         return tun->debug;
2432 #else
2433         return -EOPNOTSUPP;
2434 #endif
2435 }
2436
2437 static void tun_set_msglevel(struct net_device *dev, u32 value)
2438 {
2439 #ifdef TUN_DEBUG
2440         struct tun_struct *tun = netdev_priv(dev);
2441         tun->debug = value;
2442 #endif
2443 }
2444
2445 static const struct ethtool_ops tun_ethtool_ops = {
2446         .get_settings   = tun_get_settings,
2447         .get_drvinfo    = tun_get_drvinfo,
2448         .get_msglevel   = tun_get_msglevel,
2449         .set_msglevel   = tun_set_msglevel,
2450         .get_link       = ethtool_op_get_link,
2451         .get_ts_info    = ethtool_op_get_ts_info,
2452 };
2453
2454 static int tun_queue_resize(struct tun_struct *tun)
2455 {
2456         struct net_device *dev = tun->dev;
2457         struct tun_file *tfile;
2458         struct skb_array **arrays;
2459         int n = tun->numqueues + tun->numdisabled;
2460         int ret, i;
2461
2462         arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL);
2463         if (!arrays)
2464                 return -ENOMEM;
2465
2466         for (i = 0; i < tun->numqueues; i++) {
2467                 tfile = rtnl_dereference(tun->tfiles[i]);
2468                 arrays[i] = &tfile->tx_array;
2469         }
2470         list_for_each_entry(tfile, &tun->disabled, next)
2471                 arrays[i++] = &tfile->tx_array;
2472
2473         ret = skb_array_resize_multiple(arrays, n,
2474                                         dev->tx_queue_len, GFP_KERNEL);
2475
2476         kfree(arrays);
2477         return ret;
2478 }
2479
2480 static int tun_device_event(struct notifier_block *unused,
2481                             unsigned long event, void *ptr)
2482 {
2483         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
2484         struct tun_struct *tun = netdev_priv(dev);
2485
2486         if (dev->rtnl_link_ops != &tun_link_ops)
2487                 return NOTIFY_DONE;
2488
2489         switch (event) {
2490         case NETDEV_CHANGE_TX_QUEUE_LEN:
2491                 if (tun_queue_resize(tun))
2492                         return NOTIFY_BAD;
2493                 break;
2494         default:
2495                 break;
2496         }
2497
2498         return NOTIFY_DONE;
2499 }
2500
2501 static struct notifier_block tun_notifier_block __read_mostly = {
2502         .notifier_call  = tun_device_event,
2503 };
2504
2505 static int __init tun_init(void)
2506 {
2507         int ret = 0;
2508
2509         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2510         pr_info("%s\n", DRV_COPYRIGHT);
2511
2512         ret = rtnl_link_register(&tun_link_ops);
2513         if (ret) {
2514                 pr_err("Can't register link_ops\n");
2515                 goto err_linkops;
2516         }
2517
2518         ret = misc_register(&tun_miscdev);
2519         if (ret) {
2520                 pr_err("Can't register misc device %d\n", TUN_MINOR);
2521                 goto err_misc;
2522         }
2523
2524         register_netdevice_notifier(&tun_notifier_block);
2525         return  0;
2526 err_misc:
2527         rtnl_link_unregister(&tun_link_ops);
2528 err_linkops:
2529         return ret;
2530 }
2531
2532 static void tun_cleanup(void)
2533 {
2534         misc_deregister(&tun_miscdev);
2535         rtnl_link_unregister(&tun_link_ops);
2536         unregister_netdevice_notifier(&tun_notifier_block);
2537 }
2538
2539 /* Get an underlying socket object from tun file.  Returns error unless file is
2540  * attached to a device.  The returned object works like a packet socket, it
2541  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2542  * holding a reference to the file for as long as the socket is in use. */
2543 struct socket *tun_get_socket(struct file *file)
2544 {
2545         struct tun_file *tfile;
2546         if (file->f_op != &tun_fops)
2547                 return ERR_PTR(-EINVAL);
2548         tfile = file->private_data;
2549         if (!tfile)
2550                 return ERR_PTR(-EBADFD);
2551         return &tfile->socket;
2552 }
2553 EXPORT_SYMBOL_GPL(tun_get_socket);
2554
2555 module_init(tun_init);
2556 module_exit(tun_cleanup);
2557 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2558 MODULE_AUTHOR(DRV_COPYRIGHT);
2559 MODULE_LICENSE("GPL");
2560 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2561 MODULE_ALIAS("devname:net/tun");