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
  75 #include <asm/uaccess.h>
  76
  77 /* Uncomment to enable debugging */
  78 /* #define TUN_DEBUG 1 */
  79
  80 #ifdef TUN_DEBUG
  81 static int debug;
  82
  83 #define tun_debug(level, tun, fmt, args...)                     \
  84 do {                                                            \
  85         if (tun->debug)                                         \
  86                 netdev_printk(level, tun->dev, fmt, ##args);    \
  87 } while (0)
  88 #define DBG1(level, fmt, args...)                               \
  89 do {                                                            \
  90         if (debug == 2)                                         \
  91                 printk(level fmt, ##args);                      \
  92 } while (0)
  93 #else
  94 #define tun_debug(level, tun, fmt, args...)                     \
  95 do {                                                            \
  96         if (0)                                                  \
  97                 netdev_printk(level, tun->dev, fmt, ##args);    \
  98 } while (0)
  99 #define DBG1(level, fmt, args...)                               \
 100 do {                                                            \
 101         if (0)                                                  \
 102                 printk(level fmt, ##args);                      \
 103 } while (0)
 104 #endif
 105
 106 /* TUN device flags */
 107
 108 /* IFF_ATTACH_QUEUE is never stored in device flags,
 109  * overload it to mean fasync when stored there.
 110  */
 111 #define TUN_FASYNC      IFF_ATTACH_QUEUE
 112 /* High bits in flags field are unused. */
 113 #define TUN_VNET_LE     0x80000000
 114 #define TUN_VNET_BE     0x40000000
 115
 116 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
 117                       IFF_MULTI_QUEUE)
 118 #define GOODCOPY_LEN 128
 119
 120 #define FLT_EXACT_COUNT 8
 121 struct tap_filter {
 122         unsigned int    count;    /* Number of addrs. Zero means disabled */
 123         u32             mask[2];  /* Mask of the hashed addrs */
 124         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 125 };
 126
 127 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
 128  * to max number of VCPUs in guest. */
 129 #define MAX_TAP_QUEUES 256
 130 #define MAX_TAP_FLOWS  4096
 131
 132 #define TUN_FLOW_EXPIRE (3 * HZ)
 133
 134 /* A tun_file connects an open character device to a tuntap netdevice. It
 135  * also contains all socket related structures (except sock_fprog and tap_filter)
 136  * to serve as one transmit queue for tuntap device. The sock_fprog and
 137  * tap_filter were kept in tun_struct since they were used for filtering for the
 138  * netdevice not for a specific queue (at least I didn't see the requirement for
 139  * this).
 140  *
 141  * RCU usage:
 142  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
 143  * other can only be read while rcu_read_lock or rtnl_lock is held.
 144  */
 145 struct tun_file {
 146         struct sock sk;
 147         struct socket socket;
 148         struct socket_wq wq;
 149         struct tun_struct __rcu *tun;
 150         struct fasync_struct *fasync;
 151         /* only used for fasnyc */
 152         unsigned int flags;
 153         union {
 154                 u16 queue_index;
 155                 unsigned int ifindex;
 156         };
 157         struct list_head next;
 158         struct tun_struct *detached;
 159 };
 160
 161 struct tun_flow_entry {
 162         struct hlist_node hash_link;
 163         struct rcu_head rcu;
 164         struct tun_struct *tun;
 165
 166         u32 rxhash;
 167         u32 rps_rxhash;
 168         int queue_index;
 169         unsigned long updated;
 170 };
 171
 172 #define TUN_NUM_FLOW_ENTRIES 1024
 173
 174 /* Since the socket were moved to tun_file, to preserve the behavior of persist
 175  * device, socket filter, sndbuf and vnet header size were restore when the
 176  * file were attached to a persist device.
 177  */
 178 struct tun_struct {
 179         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
 180         unsigned int            numqueues;
 181         unsigned int            flags;
 182         kuid_t                  owner;
 183         kgid_t                  group;
 184
 185         struct net_device       *dev;
 186         netdev_features_t       set_features;
 187 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 188                           NETIF_F_TSO6|NETIF_F_UFO)
 189
 190         int                     align;
 191         int                     vnet_hdr_sz;
 192         int                     sndbuf;
 193         struct tap_filter       txflt;
 194         struct sock_fprog       fprog;
 195         /* protected by rtnl lock */
 196         bool                    filter_attached;
 197 #ifdef TUN_DEBUG
 198         int debug;
 199 #endif
 200         spinlock_t lock;
 201         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 202         struct timer_list flow_gc_timer;
 203         unsigned long ageing_time;
 204         unsigned int numdisabled;
 205         struct list_head disabled;
 206         void *security;
 207         u32 flow_count;
 208 };
 209
 210 #ifdef CONFIG_TUN_VNET_CROSS_LE
 211 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 212 {
 213         return tun->flags & TUN_VNET_BE ? false :
 214                 virtio_legacy_is_little_endian();
 215 }
 216
 217 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 218 {
 219         int be = !!(tun->flags & TUN_VNET_BE);
 220
 221         if (put_user(be, argp))
 222                 return -EFAULT;
 223
 224         return 0;
 225 }
 226
 227 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 228 {
 229         int be;
 230
 231         if (get_user(be, argp))
 232                 return -EFAULT;
 233
 234         if (be)
 235                 tun->flags |= TUN_VNET_BE;
 236         else
 237                 tun->flags &= ~TUN_VNET_BE;
 238
 239         return 0;
 240 }
 241 #else
 242 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 243 {
 244         return virtio_legacy_is_little_endian();
 245 }
 246
 247 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 248 {
 249         return -EINVAL;
 250 }
 251
 252 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 253 {
 254         return -EINVAL;
 255 }
 256 #endif /* CONFIG_TUN_VNET_CROSS_LE */
 257
 258 static inline bool tun_is_little_endian(struct tun_struct *tun)
 259 {
 260         return tun->flags & TUN_VNET_LE ||
 261                 tun_legacy_is_little_endian(tun);
 262 }
 263
 264 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
 265 {
 266         return __virtio16_to_cpu(tun_is_little_endian(tun), val);
 267 }
 268
 269 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
 270 {
 271         return __cpu_to_virtio16(tun_is_little_endian(tun), val);
 272 }
 273
 274 static inline u32 tun_hashfn(u32 rxhash)
 275 {
 276         return rxhash & 0x3ff;
 277 }
 278
 279 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 280 {
 281         struct tun_flow_entry *e;
 282
 283         hlist_for_each_entry_rcu(e, head, hash_link) {
 284                 if (e->rxhash == rxhash)
 285                         return e;
 286         }
 287         return NULL;
 288 }
 289
 290 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 291                                               struct hlist_head *head,
 292                                               u32 rxhash, u16 queue_index)
 293 {
 294         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 295
 296         if (e) {
 297                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 298                           rxhash, queue_index);
 299                 e->updated = jiffies;
 300                 e->rxhash = rxhash;
 301                 e->rps_rxhash = 0;
 302                 e->queue_index = queue_index;
 303                 e->tun = tun;
 304                 hlist_add_head_rcu(&e->hash_link, head);
 305                 ++tun->flow_count;
 306         }
 307         return e;
 308 }
 309
 310 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 311 {
 312         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 313                   e->rxhash, e->queue_index);
 314         hlist_del_rcu(&e->hash_link);
 315         kfree_rcu(e, rcu);
 316         --tun->flow_count;
 317 }
 318
 319 static void tun_flow_flush(struct tun_struct *tun)
 320 {
 321         int i;
 322
 323         spin_lock_bh(&tun->lock);
 324         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 325                 struct tun_flow_entry *e;
 326                 struct hlist_node *n;
 327
 328                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 329                         tun_flow_delete(tun, e);
 330         }
 331         spin_unlock_bh(&tun->lock);
 332 }
 333
 334 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 335 {
 336         int i;
 337
 338         spin_lock_bh(&tun->lock);
 339         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 340                 struct tun_flow_entry *e;
 341                 struct hlist_node *n;
 342
 343                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 344                         if (e->queue_index == queue_index)
 345                                 tun_flow_delete(tun, e);
 346                 }
 347         }
 348         spin_unlock_bh(&tun->lock);
 349 }
 350
 351 static void tun_flow_cleanup(unsigned long data)
 352 {
 353         struct tun_struct *tun = (struct tun_struct *)data;
 354         unsigned long delay = tun->ageing_time;
 355         unsigned long next_timer = jiffies + delay;
 356         unsigned long count = 0;
 357         int i;
 358
 359         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 360
 361         spin_lock_bh(&tun->lock);
 362         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 363                 struct tun_flow_entry *e;
 364                 struct hlist_node *n;
 365
 366                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 367                         unsigned long this_timer;
 368                         count++;
 369                         this_timer = e->updated + delay;
 370                         if (time_before_eq(this_timer, jiffies))
 371                                 tun_flow_delete(tun, e);
 372                         else if (time_before(this_timer, next_timer))
 373                                 next_timer = this_timer;
 374                 }
 375         }
 376
 377         if (count)
 378                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 379         spin_unlock_bh(&tun->lock);
 380 }
 381
 382 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 383                             struct tun_file *tfile)
 384 {
 385         struct hlist_head *head;
 386         struct tun_flow_entry *e;
 387         unsigned long delay = tun->ageing_time;
 388         u16 queue_index = tfile->queue_index;
 389
 390         if (!rxhash)
 391                 return;
 392         else
 393                 head = &tun->flows[tun_hashfn(rxhash)];
 394
 395         rcu_read_lock();
 396
 397         /* We may get a very small possibility of OOO during switching, not
 398          * worth to optimize.*/
 399         if (tun->numqueues == 1 || tfile->detached)
 400                 goto unlock;
 401
 402         e = tun_flow_find(head, rxhash);
 403         if (likely(e)) {
 404                 /* TODO: keep queueing to old queue until it's empty? */
 405                 e->queue_index = queue_index;
 406                 e->updated = jiffies;
 407                 sock_rps_record_flow_hash(e->rps_rxhash);
 408         } else {
 409                 spin_lock_bh(&tun->lock);
 410                 if (!tun_flow_find(head, rxhash) &&
 411                     tun->flow_count < MAX_TAP_FLOWS)
 412                         tun_flow_create(tun, head, rxhash, queue_index);
 413
 414                 if (!timer_pending(&tun->flow_gc_timer))
 415                         mod_timer(&tun->flow_gc_timer,
 416                                   round_jiffies_up(jiffies + delay));
 417                 spin_unlock_bh(&tun->lock);
 418         }
 419
 420 unlock:
 421         rcu_read_unlock();
 422 }
 423
 424 /**
 425  * Save the hash received in the stack receive path and update the
 426  * flow_hash table accordingly.
 427  */
 428 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
 429 {
 430         if (unlikely(e->rps_rxhash != hash))
 431                 e->rps_rxhash = hash;
 432 }
 433
 434 /* We try to identify a flow through its rxhash first. The reason that
 435  * we do not check rxq no. is because some cards(e.g 82599), chooses
 436  * the rxq based on the txq where the last packet of the flow comes. As
 437  * the userspace application move between processors, we may get a
 438  * different rxq no. here. If we could not get rxhash, then we would
 439  * hope the rxq no. may help here.
 440  */
 441 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
 442                             void *accel_priv, select_queue_fallback_t fallback)
 443 {
 444         struct tun_struct *tun = netdev_priv(dev);
 445         struct tun_flow_entry *e;
 446         u32 txq = 0;
 447         u32 numqueues = 0;
 448
 449         rcu_read_lock();
 450         numqueues = ACCESS_ONCE(tun->numqueues);
 451
 452         txq = skb_get_hash(skb);
 453         if (txq) {
 454                 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 455                 if (e) {
 456                         tun_flow_save_rps_rxhash(e, txq);
 457                         txq = e->queue_index;
 458                 } else
 459                         /* use multiply and shift instead of expensive divide */
 460                         txq = ((u64)txq * numqueues) >> 32;
 461         } else if (likely(skb_rx_queue_recorded(skb))) {
 462                 txq = skb_get_rx_queue(skb);
 463                 while (unlikely(txq >= numqueues))
 464                         txq -= numqueues;
 465         }
 466
 467         rcu_read_unlock();
 468         return txq;
 469 }
 470
 471 static inline bool tun_not_capable(struct tun_struct *tun)
 472 {
 473         const struct cred *cred = current_cred();
 474         struct net *net = dev_net(tun->dev);
 475
 476         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 477                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 478                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 479 }
 480
 481 static void tun_set_real_num_queues(struct tun_struct *tun)
 482 {
 483         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 484         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 485 }
 486
 487 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 488 {
 489         tfile->detached = tun;
 490         list_add_tail(&tfile->next, &tun->disabled);
 491         ++tun->numdisabled;
 492 }
 493
 494 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 495 {
 496         struct tun_struct *tun = tfile->detached;
 497
 498         tfile->detached = NULL;
 499         list_del_init(&tfile->next);
 500         --tun->numdisabled;
 501         return tun;
 502 }
 503
 504 static void tun_queue_purge(struct tun_file *tfile)
 505 {
 506         skb_queue_purge(&tfile->sk.sk_receive_queue);
 507         skb_queue_purge(&tfile->sk.sk_error_queue);
 508 }
 509
 510 static void __tun_detach(struct tun_file *tfile, bool clean)
 511 {
 512         struct tun_file *ntfile;
 513         struct tun_struct *tun;
 514
 515         tun = rtnl_dereference(tfile->tun);
 516
 517         if (tun && !tfile->detached) {
 518                 u16 index = tfile->queue_index;
 519                 BUG_ON(index >= tun->numqueues);
 520
 521                 rcu_assign_pointer(tun->tfiles[index],
 522                                    tun->tfiles[tun->numqueues - 1]);
 523                 ntfile = rtnl_dereference(tun->tfiles[index]);
 524                 ntfile->queue_index = index;
 525
 526                 --tun->numqueues;
 527                 if (clean) {
 528                         RCU_INIT_POINTER(tfile->tun, NULL);
 529                         sock_put(&tfile->sk);
 530                 } else
 531                         tun_disable_queue(tun, tfile);
 532
 533                 synchronize_net();
 534                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 535                 /* Drop read queue */
 536                 tun_queue_purge(tfile);
 537                 tun_set_real_num_queues(tun);
 538         } else if (tfile->detached && clean) {
 539                 tun = tun_enable_queue(tfile);
 540                 sock_put(&tfile->sk);
 541         }
 542
 543         if (clean) {
 544                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 545                         netif_carrier_off(tun->dev);
 546
 547                         if (!(tun->flags & IFF_PERSIST) &&
 548                             tun->dev->reg_state == NETREG_REGISTERED)
 549                                 unregister_netdevice(tun->dev);
 550                 }
 551                 sock_put(&tfile->sk);
 552         }
 553 }
 554
 555 static void tun_detach(struct tun_file *tfile, bool clean)
 556 {
 557         rtnl_lock();
 558         __tun_detach(tfile, clean);
 559         rtnl_unlock();
 560 }
 561
 562 static void tun_detach_all(struct net_device *dev)
 563 {
 564         struct tun_struct *tun = netdev_priv(dev);
 565         struct tun_file *tfile, *tmp;
 566         int i, n = tun->numqueues;
 567
 568         for (i = 0; i < n; i++) {
 569                 tfile = rtnl_dereference(tun->tfiles[i]);
 570                 BUG_ON(!tfile);
 571                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 572                 RCU_INIT_POINTER(tfile->tun, NULL);
 573                 --tun->numqueues;
 574         }
 575         list_for_each_entry(tfile, &tun->disabled, next) {
 576                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 577                 RCU_INIT_POINTER(tfile->tun, NULL);
 578         }
 579         BUG_ON(tun->numqueues != 0);
 580
 581         synchronize_net();
 582         for (i = 0; i < n; i++) {
 583                 tfile = rtnl_dereference(tun->tfiles[i]);
 584                 /* Drop read queue */
 585                 tun_queue_purge(tfile);
 586                 sock_put(&tfile->sk);
 587         }
 588         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 589                 tun_enable_queue(tfile);
 590                 tun_queue_purge(tfile);
 591                 sock_put(&tfile->sk);
 592         }
 593         BUG_ON(tun->numdisabled != 0);
 594
 595         if (tun->flags & IFF_PERSIST)
 596                 module_put(THIS_MODULE);
 597 }
 598
 599 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
 600 {
 601         struct tun_file *tfile = file->private_data;
 602         int err;
 603
 604         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 605         if (err < 0)
 606                 goto out;
 607
 608         err = -EINVAL;
 609         if (rtnl_dereference(tfile->tun) && !tfile->detached)
 610                 goto out;
 611
 612         err = -EBUSY;
 613         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
 614                 goto out;
 615
 616         err = -E2BIG;
 617         if (!tfile->detached &&
 618             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 619                 goto out;
 620
 621         err = 0;
 622
 623         /* Re-attach the filter to persist device */
 624         if (!skip_filter && (tun->filter_attached == true)) {
 625                 err = __sk_attach_filter(&tun->fprog, tfile->socket.sk,
 626                                          lockdep_rtnl_is_held());
 627                 if (!err)
 628                         goto out;
 629         }
 630         tfile->queue_index = tun->numqueues;
 631         rcu_assign_pointer(tfile->tun, tun);
 632         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 633         tun->numqueues++;
 634
 635         if (tfile->detached)
 636                 tun_enable_queue(tfile);
 637         else
 638                 sock_hold(&tfile->sk);
 639
 640         tun_set_real_num_queues(tun);
 641
 642         /* device is allowed to go away first, so no need to hold extra
 643          * refcnt.
 644          */
 645
 646 out:
 647         return err;
 648 }
 649
 650 static struct tun_struct *__tun_get(struct tun_file *tfile)
 651 {
 652         struct tun_struct *tun;
 653
 654         rcu_read_lock();
 655         tun = rcu_dereference(tfile->tun);
 656         if (tun)
 657                 dev_hold(tun->dev);
 658         rcu_read_unlock();
 659
 660         return tun;
 661 }
 662
 663 static struct tun_struct *tun_get(struct file *file)
 664 {
 665         return __tun_get(file->private_data);
 666 }
 667
 668 static void tun_put(struct tun_struct *tun)
 669 {
 670         dev_put(tun->dev);
 671 }
 672
 673 /* TAP filtering */
 674 static void addr_hash_set(u32 *mask, const u8 *addr)
 675 {
 676         int n = ether_crc(ETH_ALEN, addr) >> 26;
 677         mask[n >> 5] |= (1 << (n & 31));
 678 }
 679
 680 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 681 {
 682         int n = ether_crc(ETH_ALEN, addr) >> 26;
 683         return mask[n >> 5] & (1 << (n & 31));
 684 }
 685
 686 static int update_filter(struct tap_filter *filter, void __user *arg)
 687 {
 688         struct { u8 u[ETH_ALEN]; } *addr;
 689         struct tun_filter uf;
 690         int err, alen, n, nexact;
 691
 692         if (copy_from_user(&uf, arg, sizeof(uf)))
 693                 return -EFAULT;
 694
 695         if (!uf.count) {
 696                 /* Disabled */
 697                 filter->count = 0;
 698                 return 0;
 699         }
 700
 701         alen = ETH_ALEN * uf.count;
 702         addr = kmalloc(alen, GFP_KERNEL);
 703         if (!addr)
 704                 return -ENOMEM;
 705
 706         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 707                 err = -EFAULT;
 708                 goto done;
 709         }
 710
 711         /* The filter is updated without holding any locks. Which is
 712          * perfectly safe. We disable it first and in the worst
 713          * case we'll accept a few undesired packets. */
 714         filter->count = 0;
 715         wmb();
 716
 717         /* Use first set of addresses as an exact filter */
 718         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 719                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 720
 721         nexact = n;
 722
 723         /* Remaining multicast addresses are hashed,
 724          * unicast will leave the filter disabled. */
 725         memset(filter->mask, 0, sizeof(filter->mask));
 726         for (; n < uf.count; n++) {
 727                 if (!is_multicast_ether_addr(addr[n].u)) {
 728                         err = 0; /* no filter */
 729                         goto done;
 730                 }
 731                 addr_hash_set(filter->mask, addr[n].u);
 732         }
 733
 734         /* For ALLMULTI just set the mask to all ones.
 735          * This overrides the mask populated above. */
 736         if ((uf.flags & TUN_FLT_ALLMULTI))
 737                 memset(filter->mask, ~0, sizeof(filter->mask));
 738
 739         /* Now enable the filter */
 740         wmb();
 741         filter->count = nexact;
 742
 743         /* Return the number of exact filters */
 744         err = nexact;
 745
 746 done:
 747         kfree(addr);
 748         return err;
 749 }
 750
 751 /* Returns: 0 - drop, !=0 - accept */
 752 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 753 {
 754         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 755          * at this point. */
 756         struct ethhdr *eh = (struct ethhdr *) skb->data;
 757         int i;
 758
 759         /* Exact match */
 760         for (i = 0; i < filter->count; i++)
 761                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 762                         return 1;
 763
 764         /* Inexact match (multicast only) */
 765         if (is_multicast_ether_addr(eh->h_dest))
 766                 return addr_hash_test(filter->mask, eh->h_dest);
 767
 768         return 0;
 769 }
 770
 771 /*
 772  * Checks whether the packet is accepted or not.
 773  * Returns: 0 - drop, !=0 - accept
 774  */
 775 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 776 {
 777         if (!filter->count)
 778                 return 1;
 779
 780         return run_filter(filter, skb);
 781 }
 782
 783 /* Network device part of the driver */
 784
 785 static const struct ethtool_ops tun_ethtool_ops;
 786
 787 /* Net device detach from fd. */
 788 static void tun_net_uninit(struct net_device *dev)
 789 {
 790         tun_detach_all(dev);
 791 }
 792
 793 /* Net device open. */
 794 static int tun_net_open(struct net_device *dev)
 795 {
 796         netif_tx_start_all_queues(dev);
 797         return 0;
 798 }
 799
 800 /* Net device close. */
 801 static int tun_net_close(struct net_device *dev)
 802 {
 803         netif_tx_stop_all_queues(dev);
 804         return 0;
 805 }
 806
 807 /* Net device start xmit */
 808 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 809 {
 810         struct tun_struct *tun = netdev_priv(dev);
 811         int txq = skb->queue_mapping;
 812         struct tun_file *tfile;
 813         u32 numqueues = 0;
 814
 815         rcu_read_lock();
 816         tfile = rcu_dereference(tun->tfiles[txq]);
 817         numqueues = ACCESS_ONCE(tun->numqueues);
 818
 819         /* Drop packet if interface is not attached */
 820         if (txq >= numqueues)
 821                 goto drop;
 822
 823         if (numqueues == 1) {
 824                 /* Select queue was not called for the skbuff, so we extract the
 825                  * RPS hash and save it into the flow_table here.
 826                  */
 827                 __u32 rxhash;
 828
 829                 rxhash = skb_get_hash(skb);
 830                 if (rxhash) {
 831                         struct tun_flow_entry *e;
 832                         e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
 833                                         rxhash);
 834                         if (e)
 835                                 tun_flow_save_rps_rxhash(e, rxhash);
 836                 }
 837         }
 838
 839         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 840
 841         BUG_ON(!tfile);
 842
 843         /* Drop if the filter does not like it.
 844          * This is a noop if the filter is disabled.
 845          * Filter can be enabled only for the TAP devices. */
 846         if (!check_filter(&tun->txflt, skb))
 847                 goto drop;
 848
 849         if (tfile->socket.sk->sk_filter &&
 850             sk_filter(tfile->socket.sk, skb))
 851                 goto drop;
 852
 853         /* Limit the number of packets queued by dividing txq length with the
 854          * number of queues.
 855          */
 856         if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues
 857                           >= dev->tx_queue_len)
 858                 goto drop;
 859
 860         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 861                 goto drop;
 862
 863         if (skb->sk && sk_fullsock(skb->sk)) {
 864                 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags);
 865                 sw_tx_timestamp(skb);
 866         }
 867
 868         /* Orphan the skb - required as we might hang on to it
 869          * for indefinite time.
 870          */
 871         skb_orphan(skb);
 872
 873         nf_reset(skb);
 874
 875         /* Enqueue packet */
 876         skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
 877
 878         /* Notify and wake up reader process */
 879         if (tfile->flags & TUN_FASYNC)
 880                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
 881         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 882
 883         rcu_read_unlock();
 884         return NETDEV_TX_OK;
 885
 886 drop:
 887         dev->stats.tx_dropped++;
 888         skb_tx_error(skb);
 889         kfree_skb(skb);
 890         rcu_read_unlock();
 891         return NET_XMIT_DROP;
 892 }
 893
 894 static void tun_net_mclist(struct net_device *dev)
 895 {
 896         /*
 897          * This callback is supposed to deal with mc filter in
 898          * _rx_ path and has nothing to do with the _tx_ path.
 899          * In rx path we always accept everything userspace gives us.
 900          */
 901 }
 902
 903 #define MIN_MTU 68
 904 #define MAX_MTU 65535
 905
 906 static int
 907 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 908 {
 909         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 910                 return -EINVAL;
 911         dev->mtu = new_mtu;
 912         return 0;
 913 }
 914
 915 static netdev_features_t tun_net_fix_features(struct net_device *dev,
 916         netdev_features_t features)
 917 {
 918         struct tun_struct *tun = netdev_priv(dev);
 919
 920         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 921 }
 922 #ifdef CONFIG_NET_POLL_CONTROLLER
 923 static void tun_poll_controller(struct net_device *dev)
 924 {
 925         /*
 926          * Tun only receives frames when:
 927          * 1) the char device endpoint gets data from user space
 928          * 2) the tun socket gets a sendmsg call from user space
 929          * Since both of those are synchronous operations, we are guaranteed
 930          * never to have pending data when we poll for it
 931          * so there is nothing to do here but return.
 932          * We need this though so netpoll recognizes us as an interface that
 933          * supports polling, which enables bridge devices in virt setups to
 934          * still use netconsole
 935          */
 936         return;
 937 }
 938 #endif
 939
 940 static void tun_set_headroom(struct net_device *dev, int new_hr)
 941 {
 942         struct tun_struct *tun = netdev_priv(dev);
 943
 944         if (new_hr < NET_SKB_PAD)
 945                 new_hr = NET_SKB_PAD;
 946
 947         tun->align = new_hr;
 948 }
 949
 950 static const struct net_device_ops tun_netdev_ops = {
 951         .ndo_uninit             = tun_net_uninit,
 952         .ndo_open               = tun_net_open,
 953         .ndo_stop               = tun_net_close,
 954         .ndo_start_xmit         = tun_net_xmit,
 955         .ndo_change_mtu         = tun_net_change_mtu,
 956         .ndo_fix_features       = tun_net_fix_features,
 957         .ndo_select_queue       = tun_select_queue,
 958 #ifdef CONFIG_NET_POLL_CONTROLLER
 959         .ndo_poll_controller    = tun_poll_controller,
 960 #endif
 961         .ndo_set_rx_headroom    = tun_set_headroom,
 962 };
 963
 964 static const struct net_device_ops tap_netdev_ops = {
 965         .ndo_uninit             = tun_net_uninit,
 966         .ndo_open               = tun_net_open,
 967         .ndo_stop               = tun_net_close,
 968         .ndo_start_xmit         = tun_net_xmit,
 969         .ndo_change_mtu         = tun_net_change_mtu,
 970         .ndo_fix_features       = tun_net_fix_features,
 971         .ndo_set_rx_mode        = tun_net_mclist,
 972         .ndo_set_mac_address    = eth_mac_addr,
 973         .ndo_validate_addr      = eth_validate_addr,
 974         .ndo_select_queue       = tun_select_queue,
 975 #ifdef CONFIG_NET_POLL_CONTROLLER
 976         .ndo_poll_controller    = tun_poll_controller,
 977 #endif
 978         .ndo_features_check     = passthru_features_check,
 979         .ndo_set_rx_headroom    = tun_set_headroom,
 980 };
 981
 982 static void tun_flow_init(struct tun_struct *tun)
 983 {
 984         int i;
 985
 986         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
 987                 INIT_HLIST_HEAD(&tun->flows[i]);
 988
 989         tun->ageing_time = TUN_FLOW_EXPIRE;
 990         setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
 991         mod_timer(&tun->flow_gc_timer,
 992                   round_jiffies_up(jiffies + tun->ageing_time));
 993 }
 994
 995 static void tun_flow_uninit(struct tun_struct *tun)
 996 {
 997         del_timer_sync(&tun->flow_gc_timer);
 998         tun_flow_flush(tun);
 999 }
1000
1001 /* Initialize net device. */
1002 static void tun_net_init(struct net_device *dev)
1003 {
1004         struct tun_struct *tun = netdev_priv(dev);
1005
1006         switch (tun->flags & TUN_TYPE_MASK) {
1007         case IFF_TUN:
1008                 dev->netdev_ops = &tun_netdev_ops;
1009
1010                 /* Point-to-Point TUN Device */
1011                 dev->hard_header_len = 0;
1012                 dev->addr_len = 0;
1013                 dev->mtu = 1500;
1014
1015                 /* Zero header length */
1016                 dev->type = ARPHRD_NONE;
1017                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1018                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
1019                 break;
1020
1021         case IFF_TAP:
1022                 dev->netdev_ops = &tap_netdev_ops;
1023                 /* Ethernet TAP Device */
1024                 ether_setup(dev);
1025                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1026                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1027
1028                 eth_hw_addr_random(dev);
1029
1030                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
1031                 break;
1032         }
1033 }
1034
1035 /* Character device part */
1036
1037 /* Poll */
1038 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1039 {
1040         struct tun_file *tfile = file->private_data;
1041         struct tun_struct *tun = __tun_get(tfile);
1042         struct sock *sk;
1043         unsigned int mask = 0;
1044
1045         if (!tun)
1046                 return POLLERR;
1047
1048         sk = tfile->socket.sk;
1049
1050         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1051
1052         poll_wait(file, sk_sleep(sk), wait);
1053
1054         if (!skb_queue_empty(&sk->sk_receive_queue))
1055                 mask |= POLLIN | POLLRDNORM;
1056
1057         if (sock_writeable(sk) ||
1058             (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1059              sock_writeable(sk)))
1060                 mask |= POLLOUT | POLLWRNORM;
1061
1062         if (tun->dev->reg_state != NETREG_REGISTERED)
1063                 mask = POLLERR;
1064
1065         tun_put(tun);
1066         return mask;
1067 }
1068
1069 /* prepad is the amount to reserve at front.  len is length after that.
1070  * linear is a hint as to how much to copy (usually headers). */
1071 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1072                                      size_t prepad, size_t len,
1073                                      size_t linear, int noblock)
1074 {
1075         struct sock *sk = tfile->socket.sk;
1076         struct sk_buff *skb;
1077         int err;
1078
1079         /* Under a page?  Don't bother with paged skb. */
1080         if (prepad + len < PAGE_SIZE || !linear)
1081                 linear = len;
1082
1083         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1084                                    &err, 0);
1085         if (!skb)
1086                 return ERR_PTR(err);
1087
1088         skb_reserve(skb, prepad);
1089         skb_put(skb, linear);
1090         skb->data_len = len - linear;
1091         skb->len += len - linear;
1092
1093         return skb;
1094 }
1095
1096 /* Get packet from user space buffer */
1097 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1098                             void *msg_control, struct iov_iter *from,
1099                             int noblock)
1100 {
1101         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1102         struct sk_buff *skb;
1103         size_t total_len = iov_iter_count(from);
1104         size_t len = total_len, align = tun->align, linear;
1105         struct virtio_net_hdr gso = { 0 };
1106         int good_linear;
1107         int copylen;
1108         bool zerocopy = false;
1109         int err;
1110         u32 rxhash;
1111         ssize_t n;
1112
1113         if (!(tun->dev->flags & IFF_UP))
1114                 return -EIO;
1115
1116         if (!(tun->flags & IFF_NO_PI)) {
1117                 if (len < sizeof(pi))
1118                         return -EINVAL;
1119                 len -= sizeof(pi);
1120
1121                 n = copy_from_iter(&pi, sizeof(pi), from);
1122                 if (n != sizeof(pi))
1123                         return -EFAULT;
1124         }
1125
1126         if (tun->flags & IFF_VNET_HDR) {
1127                 if (len < tun->vnet_hdr_sz)
1128                         return -EINVAL;
1129                 len -= tun->vnet_hdr_sz;
1130
1131                 n = copy_from_iter(&gso, sizeof(gso), from);
1132                 if (n != sizeof(gso))
1133                         return -EFAULT;
1134
1135                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1136                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1137                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1138
1139                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1140                         return -EINVAL;
1141                 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso));
1142         }
1143
1144         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1145                 align += NET_IP_ALIGN;
1146                 if (unlikely(len < ETH_HLEN ||
1147                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1148                         return -EINVAL;
1149         }
1150
1151         good_linear = SKB_MAX_HEAD(align);
1152
1153         if (msg_control) {
1154                 struct iov_iter i = *from;
1155
1156                 /* There are 256 bytes to be copied in skb, so there is
1157                  * enough room for skb expand head in case it is used.
1158                  * The rest of the buffer is mapped from userspace.
1159                  */
1160                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1161                 if (copylen > good_linear)
1162                         copylen = good_linear;
1163                 linear = copylen;
1164                 iov_iter_advance(&i, copylen);
1165                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1166                         zerocopy = true;
1167         }
1168
1169         if (!zerocopy) {
1170                 copylen = len;
1171                 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1172                         linear = good_linear;
1173                 else
1174                         linear = tun16_to_cpu(tun, gso.hdr_len);
1175         }
1176
1177         skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1178         if (IS_ERR(skb)) {
1179                 if (PTR_ERR(skb) != -EAGAIN)
1180                         tun->dev->stats.rx_dropped++;
1181                 return PTR_ERR(skb);
1182         }
1183
1184         if (zerocopy)
1185                 err = zerocopy_sg_from_iter(skb, from);
1186         else {
1187                 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1188                 if (!err && msg_control) {
1189                         struct ubuf_info *uarg = msg_control;
1190                         uarg->callback(uarg, false);
1191                 }
1192         }
1193
1194         if (err) {
1195                 tun->dev->stats.rx_dropped++;
1196                 kfree_skb(skb);
1197                 return -EFAULT;
1198         }
1199
1200         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1201                 if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start),
1202                                           tun16_to_cpu(tun, gso.csum_offset))) {
1203                         tun->dev->stats.rx_frame_errors++;
1204                         kfree_skb(skb);
1205                         return -EINVAL;
1206                 }
1207         }
1208
1209         switch (tun->flags & TUN_TYPE_MASK) {
1210         case IFF_TUN:
1211                 if (tun->flags & IFF_NO_PI) {
1212                         switch (skb->data[0] & 0xf0) {
1213                         case 0x40:
1214                                 pi.proto = htons(ETH_P_IP);
1215                                 break;
1216                         case 0x60:
1217                                 pi.proto = htons(ETH_P_IPV6);
1218                                 break;
1219                         default:
1220                                 tun->dev->stats.rx_dropped++;
1221                                 kfree_skb(skb);
1222                                 return -EINVAL;
1223                         }
1224                 }
1225
1226                 skb_reset_mac_header(skb);
1227                 skb->protocol = pi.proto;
1228                 skb->dev = tun->dev;
1229                 break;
1230         case IFF_TAP:
1231                 skb->protocol = eth_type_trans(skb, tun->dev);
1232                 break;
1233         }
1234
1235         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1236                 pr_debug("GSO!\n");
1237                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1238                 case VIRTIO_NET_HDR_GSO_TCPV4:
1239                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1240                         break;
1241                 case VIRTIO_NET_HDR_GSO_TCPV6:
1242                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1243                         break;
1244                 case VIRTIO_NET_HDR_GSO_UDP:
1245                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1246                         break;
1247                 default:
1248                         tun->dev->stats.rx_frame_errors++;
1249                         kfree_skb(skb);
1250                         return -EINVAL;
1251                 }
1252
1253                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1254                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1255
1256                 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size);
1257                 if (skb_shinfo(skb)->gso_size == 0) {
1258                         tun->dev->stats.rx_frame_errors++;
1259                         kfree_skb(skb);
1260                         return -EINVAL;
1261                 }
1262
1263                 /* Header must be checked, and gso_segs computed. */
1264                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1265                 skb_shinfo(skb)->gso_segs = 0;
1266         }
1267
1268         /* copy skb_ubuf_info for callback when skb has no error */
1269         if (zerocopy) {
1270                 skb_shinfo(skb)->destructor_arg = msg_control;
1271                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1272                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1273         }
1274
1275         skb_reset_network_header(skb);
1276         skb_probe_transport_header(skb, 0);
1277
1278         rxhash = skb_get_hash(skb);
1279         netif_rx_ni(skb);
1280
1281         tun->dev->stats.rx_packets++;
1282         tun->dev->stats.rx_bytes += len;
1283
1284         tun_flow_update(tun, rxhash, tfile);
1285         return total_len;
1286 }
1287
1288 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1289 {
1290         struct file *file = iocb->ki_filp;
1291         struct tun_struct *tun = tun_get(file);
1292         struct tun_file *tfile = file->private_data;
1293         ssize_t result;
1294
1295         if (!tun)
1296                 return -EBADFD;
1297
1298         result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);
1299
1300         tun_put(tun);
1301         return result;
1302 }
1303
1304 /* Put packet to the user space buffer */
1305 static ssize_t tun_put_user(struct tun_struct *tun,
1306                             struct tun_file *tfile,
1307                             struct sk_buff *skb,
1308                             struct iov_iter *iter)
1309 {
1310         struct tun_pi pi = { 0, skb->protocol };
1311         ssize_t total;
1312         int vlan_offset = 0;
1313         int vlan_hlen = 0;
1314         int vnet_hdr_sz = 0;
1315
1316         if (skb_vlan_tag_present(skb))
1317                 vlan_hlen = VLAN_HLEN;
1318
1319         if (tun->flags & IFF_VNET_HDR)
1320                 vnet_hdr_sz = tun->vnet_hdr_sz;
1321
1322         total = skb->len + vlan_hlen + vnet_hdr_sz;
1323
1324         if (!(tun->flags & IFF_NO_PI)) {
1325                 if (iov_iter_count(iter) < sizeof(pi))
1326                         return -EINVAL;
1327
1328                 total += sizeof(pi);
1329                 if (iov_iter_count(iter) < total) {
1330                         /* Packet will be striped */
1331                         pi.flags |= TUN_PKT_STRIP;
1332                 }
1333
1334                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1335                         return -EFAULT;
1336         }
1337
1338         if (vnet_hdr_sz) {
1339                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1340                 if (iov_iter_count(iter) < vnet_hdr_sz)
1341                         return -EINVAL;
1342
1343                 if (skb_is_gso(skb)) {
1344                         struct skb_shared_info *sinfo = skb_shinfo(skb);
1345
1346                         /* This is a hint as to how much should be linear. */
1347                         gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb));
1348                         gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size);
1349                         if (sinfo->gso_type & SKB_GSO_TCPV4)
1350                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1351                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
1352                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1353                         else if (sinfo->gso_type & SKB_GSO_UDP)
1354                                 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1355                         else {
1356                                 pr_err("unexpected GSO type: "
1357                                        "0x%x, gso_size %d, hdr_len %d\n",
1358                                        sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1359                                        tun16_to_cpu(tun, gso.hdr_len));
1360                                 print_hex_dump(KERN_ERR, "tun: ",
1361                                                DUMP_PREFIX_NONE,
1362                                                16, 1, skb->head,
1363                                                min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1364                                 WARN_ON_ONCE(1);
1365                                 return -EINVAL;
1366                         }
1367                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1368                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1369                 } else
1370                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1371
1372                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1373                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1374                         gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) +
1375                                                       vlan_hlen);
1376                         gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset);
1377                 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1378                         gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1379                 } /* else everything is zero */
1380
1381                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1382                         return -EFAULT;
1383
1384                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1385         }
1386
1387         if (vlan_hlen) {
1388                 int ret;
1389                 struct {
1390                         __be16 h_vlan_proto;
1391                         __be16 h_vlan_TCI;
1392                 } veth;
1393
1394                 veth.h_vlan_proto = skb->vlan_proto;
1395                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1396
1397                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1398
1399                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1400                 if (ret || !iov_iter_count(iter))
1401                         goto done;
1402
1403                 ret = copy_to_iter(&veth, sizeof(veth), iter);
1404                 if (ret != sizeof(veth) || !iov_iter_count(iter))
1405                         goto done;
1406         }
1407
1408         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1409
1410 done:
1411         tun->dev->stats.tx_packets++;
1412         tun->dev->stats.tx_bytes += skb->len + vlan_hlen;
1413
1414         return total;
1415 }
1416
1417 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1418                            struct iov_iter *to,
1419                            int noblock)
1420 {
1421         struct sk_buff *skb;
1422         ssize_t ret;
1423         int peeked, err, off = 0;
1424
1425         tun_debug(KERN_INFO, tun, "tun_do_read\n");
1426
1427         if (!iov_iter_count(to))
1428                 return 0;
1429
1430         if (tun->dev->reg_state != NETREG_REGISTERED)
1431                 return -EIO;
1432
1433         /* Read frames from queue */
1434         skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0,
1435                                   &peeked, &off, &err);
1436         if (!skb)
1437                 return err;
1438
1439         ret = tun_put_user(tun, tfile, skb, to);
1440         if (unlikely(ret < 0))
1441                 kfree_skb(skb);
1442         else
1443                 consume_skb(skb);
1444
1445         return ret;
1446 }
1447
1448 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1449 {
1450         struct file *file = iocb->ki_filp;
1451         struct tun_file *tfile = file->private_data;
1452         struct tun_struct *tun = __tun_get(tfile);
1453         ssize_t len = iov_iter_count(to), ret;
1454
1455         if (!tun)
1456                 return -EBADFD;
1457         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
1458         ret = min_t(ssize_t, ret, len);
1459         if (ret > 0)
1460                 iocb->ki_pos = ret;
1461         tun_put(tun);
1462         return ret;
1463 }
1464
1465 static void tun_free_netdev(struct net_device *dev)
1466 {
1467         struct tun_struct *tun = netdev_priv(dev);
1468
1469         BUG_ON(!(list_empty(&tun->disabled)));
1470         tun_flow_uninit(tun);
1471         security_tun_dev_free_security(tun->security);
1472         free_netdev(dev);
1473 }
1474
1475 static void tun_setup(struct net_device *dev)
1476 {
1477         struct tun_struct *tun = netdev_priv(dev);
1478
1479         tun->owner = INVALID_UID;
1480         tun->group = INVALID_GID;
1481
1482         dev->ethtool_ops = &tun_ethtool_ops;
1483         dev->destructor = tun_free_netdev;
1484 }
1485
1486 /* Trivial set of netlink ops to allow deleting tun or tap
1487  * device with netlink.
1488  */
1489 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1490 {
1491         return -EINVAL;
1492 }
1493
1494 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1495         .kind           = DRV_NAME,
1496         .priv_size      = sizeof(struct tun_struct),
1497         .setup          = tun_setup,
1498         .validate       = tun_validate,
1499 };
1500
1501 static void tun_sock_write_space(struct sock *sk)
1502 {
1503         struct tun_file *tfile;
1504         wait_queue_head_t *wqueue;
1505
1506         if (!sock_writeable(sk))
1507                 return;
1508
1509         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
1510                 return;
1511
1512         wqueue = sk_sleep(sk);
1513         if (wqueue && waitqueue_active(wqueue))
1514                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1515                                                 POLLWRNORM | POLLWRBAND);
1516
1517         tfile = container_of(sk, struct tun_file, sk);
1518         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1519 }
1520
1521 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1522 {
1523         int ret;
1524         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1525         struct tun_struct *tun = __tun_get(tfile);
1526
1527         if (!tun)
1528                 return -EBADFD;
1529
1530         ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1531                            m->msg_flags & MSG_DONTWAIT);
1532         tun_put(tun);
1533         return ret;
1534 }
1535
1536 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1537                        int flags)
1538 {
1539         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1540         struct tun_struct *tun = __tun_get(tfile);
1541         int ret;
1542
1543         if (!tun)
1544                 return -EBADFD;
1545
1546         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1547                 ret = -EINVAL;
1548                 goto out;
1549         }
1550         if (flags & MSG_ERRQUEUE) {
1551                 ret = sock_recv_errqueue(sock->sk, m, total_len,
1552                                          SOL_PACKET, TUN_TX_TIMESTAMP);
1553                 goto out;
1554         }
1555         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1556         if (ret > (ssize_t)total_len) {
1557                 m->msg_flags |= MSG_TRUNC;
1558                 ret = flags & MSG_TRUNC ? ret : total_len;
1559         }
1560 out:
1561         tun_put(tun);
1562         return ret;
1563 }
1564
1565 /* Ops structure to mimic raw sockets with tun */
1566 static const struct proto_ops tun_socket_ops = {
1567         .sendmsg = tun_sendmsg,
1568         .recvmsg = tun_recvmsg,
1569 };
1570
1571 static struct proto tun_proto = {
1572         .name           = "tun",
1573         .owner          = THIS_MODULE,
1574         .obj_size       = sizeof(struct tun_file),
1575 };
1576
1577 static int tun_flags(struct tun_struct *tun)
1578 {
1579         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1580 }
1581
1582 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1583                               char *buf)
1584 {
1585         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1586         return sprintf(buf, "0x%x\n", tun_flags(tun));
1587 }
1588
1589 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1590                               char *buf)
1591 {
1592         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1593         return uid_valid(tun->owner)?
1594                 sprintf(buf, "%u\n",
1595                         from_kuid_munged(current_user_ns(), tun->owner)):
1596                 sprintf(buf, "-1\n");
1597 }
1598
1599 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1600                               char *buf)
1601 {
1602         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1603         return gid_valid(tun->group) ?
1604                 sprintf(buf, "%u\n",
1605                         from_kgid_munged(current_user_ns(), tun->group)):
1606                 sprintf(buf, "-1\n");
1607 }
1608
1609 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1610 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1611 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1612
1613 static struct attribute *tun_dev_attrs[] = {
1614         &dev_attr_tun_flags.attr,
1615         &dev_attr_owner.attr,
1616         &dev_attr_group.attr,
1617         NULL
1618 };
1619
1620 static const struct attribute_group tun_attr_group = {
1621         .attrs = tun_dev_attrs
1622 };
1623
1624 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1625 {
1626         struct tun_struct *tun;
1627         struct tun_file *tfile = file->private_data;
1628         struct net_device *dev;
1629         int err;
1630
1631         if (tfile->detached)
1632                 return -EINVAL;
1633
1634         dev = __dev_get_by_name(net, ifr->ifr_name);
1635         if (dev) {
1636                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1637                         return -EBUSY;
1638                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1639                         tun = netdev_priv(dev);
1640                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1641                         tun = netdev_priv(dev);
1642                 else
1643                         return -EINVAL;
1644
1645                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1646                     !!(tun->flags & IFF_MULTI_QUEUE))
1647                         return -EINVAL;
1648
1649                 if (tun_not_capable(tun))
1650                         return -EPERM;
1651                 err = security_tun_dev_open(tun->security);
1652                 if (err < 0)
1653                         return err;
1654
1655                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1656                 if (err < 0)
1657                         return err;
1658
1659                 if (tun->flags & IFF_MULTI_QUEUE &&
1660                     (tun->numqueues + tun->numdisabled > 1)) {
1661                         /* One or more queue has already been attached, no need
1662                          * to initialize the device again.
1663                          */
1664                         return 0;
1665                 }
1666         }
1667         else {
1668                 char *name;
1669                 unsigned long flags = 0;
1670                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1671                              MAX_TAP_QUEUES : 1;
1672
1673                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1674                         return -EPERM;
1675                 err = security_tun_dev_create();
1676                 if (err < 0)
1677                         return err;
1678
1679                 /* Set dev type */
1680                 if (ifr->ifr_flags & IFF_TUN) {
1681                         /* TUN device */
1682                         flags |= IFF_TUN;
1683                         name = "tun%d";
1684                 } else if (ifr->ifr_flags & IFF_TAP) {
1685                         /* TAP device */
1686                         flags |= IFF_TAP;
1687                         name = "tap%d";
1688                 } else
1689                         return -EINVAL;
1690
1691                 if (*ifr->ifr_name)
1692                         name = ifr->ifr_name;
1693
1694                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1695                                        NET_NAME_UNKNOWN, tun_setup, queues,
1696                                        queues);
1697
1698                 if (!dev)
1699                         return -ENOMEM;
1700
1701                 dev_net_set(dev, net);
1702                 dev->rtnl_link_ops = &tun_link_ops;
1703                 dev->ifindex = tfile->ifindex;
1704                 dev->sysfs_groups[0] = &tun_attr_group;
1705
1706                 tun = netdev_priv(dev);
1707                 tun->dev = dev;
1708                 tun->flags = flags;
1709                 tun->txflt.count = 0;
1710                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1711
1712                 tun->align = NET_SKB_PAD;
1713                 tun->filter_attached = false;
1714                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1715
1716                 spin_lock_init(&tun->lock);
1717
1718                 err = security_tun_dev_alloc_security(&tun->security);
1719                 if (err < 0)
1720                         goto err_free_dev;
1721
1722                 tun_net_init(dev);
1723                 tun_flow_init(tun);
1724
1725                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1726                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1727                                    NETIF_F_HW_VLAN_STAG_TX;
1728                 dev->features = dev->hw_features;
1729                 dev->vlan_features = dev->features &
1730                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
1731                                        NETIF_F_HW_VLAN_STAG_TX);
1732
1733                 INIT_LIST_HEAD(&tun->disabled);
1734                 err = tun_attach(tun, file, false);
1735                 if (err < 0)
1736                         goto err_free_flow;
1737
1738                 err = register_netdevice(tun->dev);
1739                 if (err < 0)
1740                         goto err_detach;
1741         }
1742
1743         netif_carrier_on(tun->dev);
1744
1745         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1746
1747         tun->flags = (tun->flags & ~TUN_FEATURES) |
1748                 (ifr->ifr_flags & TUN_FEATURES);
1749
1750         /* Make sure persistent devices do not get stuck in
1751          * xoff state.
1752          */
1753         if (netif_running(tun->dev))
1754                 netif_tx_wake_all_queues(tun->dev);
1755
1756         strcpy(ifr->ifr_name, tun->dev->name);
1757         return 0;
1758
1759 err_detach:
1760         tun_detach_all(dev);
1761 err_free_flow:
1762         tun_flow_uninit(tun);
1763         security_tun_dev_free_security(tun->security);
1764 err_free_dev:
1765         free_netdev(dev);
1766         return err;
1767 }
1768
1769 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1770                        struct ifreq *ifr)
1771 {
1772         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1773
1774         strcpy(ifr->ifr_name, tun->dev->name);
1775
1776         ifr->ifr_flags = tun_flags(tun);
1777
1778 }
1779
1780 /* This is like a cut-down ethtool ops, except done via tun fd so no
1781  * privs required. */
1782 static int set_offload(struct tun_struct *tun, unsigned long arg)
1783 {
1784         netdev_features_t features = 0;
1785
1786         if (arg & TUN_F_CSUM) {
1787                 features |= NETIF_F_HW_CSUM;
1788                 arg &= ~TUN_F_CSUM;
1789
1790                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1791                         if (arg & TUN_F_TSO_ECN) {
1792                                 features |= NETIF_F_TSO_ECN;
1793                                 arg &= ~TUN_F_TSO_ECN;
1794                         }
1795                         if (arg & TUN_F_TSO4)
1796                                 features |= NETIF_F_TSO;
1797                         if (arg & TUN_F_TSO6)
1798                                 features |= NETIF_F_TSO6;
1799                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1800                 }
1801
1802                 if (arg & TUN_F_UFO) {
1803                         features |= NETIF_F_UFO;
1804                         arg &= ~TUN_F_UFO;
1805                 }
1806         }
1807
1808         /* This gives the user a way to test for new features in future by
1809          * trying to set them. */
1810         if (arg)
1811                 return -EINVAL;
1812
1813         tun->set_features = features;
1814         netdev_update_features(tun->dev);
1815
1816         return 0;
1817 }
1818
1819 static void tun_detach_filter(struct tun_struct *tun, int n)
1820 {
1821         int i;
1822         struct tun_file *tfile;
1823
1824         for (i = 0; i < n; i++) {
1825                 tfile = rtnl_dereference(tun->tfiles[i]);
1826                 __sk_detach_filter(tfile->socket.sk, lockdep_rtnl_is_held());
1827         }
1828
1829         tun->filter_attached = false;
1830 }
1831
1832 static int tun_attach_filter(struct tun_struct *tun)
1833 {
1834         int i, ret = 0;
1835         struct tun_file *tfile;
1836
1837         for (i = 0; i < tun->numqueues; i++) {
1838                 tfile = rtnl_dereference(tun->tfiles[i]);
1839                 ret = __sk_attach_filter(&tun->fprog, tfile->socket.sk,
1840                                          lockdep_rtnl_is_held());
1841                 if (ret) {
1842                         tun_detach_filter(tun, i);
1843                         return ret;
1844                 }
1845         }
1846
1847         tun->filter_attached = true;
1848         return ret;
1849 }
1850
1851 static void tun_set_sndbuf(struct tun_struct *tun)
1852 {
1853         struct tun_file *tfile;
1854         int i;
1855
1856         for (i = 0; i < tun->numqueues; i++) {
1857                 tfile = rtnl_dereference(tun->tfiles[i]);
1858                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1859         }
1860 }
1861
1862 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1863 {
1864         struct tun_file *tfile = file->private_data;
1865         struct tun_struct *tun;
1866         int ret = 0;
1867
1868         rtnl_lock();
1869
1870         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1871                 tun = tfile->detached;
1872                 if (!tun) {
1873                         ret = -EINVAL;
1874                         goto unlock;
1875                 }
1876                 ret = security_tun_dev_attach_queue(tun->security);
1877                 if (ret < 0)
1878                         goto unlock;
1879                 ret = tun_attach(tun, file, false);
1880         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1881                 tun = rtnl_dereference(tfile->tun);
1882                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1883                         ret = -EINVAL;
1884                 else
1885                         __tun_detach(tfile, false);
1886         } else
1887                 ret = -EINVAL;
1888
1889 unlock:
1890         rtnl_unlock();
1891         return ret;
1892 }
1893
1894 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1895                             unsigned long arg, int ifreq_len)
1896 {
1897         struct tun_file *tfile = file->private_data;
1898         struct tun_struct *tun;
1899         void __user* argp = (void __user*)arg;
1900         struct ifreq ifr;
1901         kuid_t owner;
1902         kgid_t group;
1903         int sndbuf;
1904         int vnet_hdr_sz;
1905         unsigned int ifindex;
1906         int le;
1907         int ret;
1908
1909         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1910                 if (copy_from_user(&ifr, argp, ifreq_len))
1911                         return -EFAULT;
1912         } else {
1913                 memset(&ifr, 0, sizeof(ifr));
1914         }
1915         if (cmd == TUNGETFEATURES) {
1916                 /* Currently this just means: "what IFF flags are valid?".
1917                  * This is needed because we never checked for invalid flags on
1918                  * TUNSETIFF.
1919                  */
1920                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
1921                                 (unsigned int __user*)argp);
1922         } else if (cmd == TUNSETQUEUE)
1923                 return tun_set_queue(file, &ifr);
1924
1925         ret = 0;
1926         rtnl_lock();
1927
1928         tun = __tun_get(tfile);
1929         if (cmd == TUNSETIFF && !tun) {
1930                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1931
1932                 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
1933
1934                 if (ret)
1935                         goto unlock;
1936
1937                 if (copy_to_user(argp, &ifr, ifreq_len))
1938                         ret = -EFAULT;
1939                 goto unlock;
1940         }
1941         if (cmd == TUNSETIFINDEX) {
1942                 ret = -EPERM;
1943                 if (tun)
1944                         goto unlock;
1945
1946                 ret = -EFAULT;
1947                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
1948                         goto unlock;
1949
1950                 ret = 0;
1951                 tfile->ifindex = ifindex;
1952                 goto unlock;
1953         }
1954
1955         ret = -EBADFD;
1956         if (!tun)
1957                 goto unlock;
1958
1959         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1960
1961         ret = 0;
1962         switch (cmd) {
1963         case TUNGETIFF:
1964                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1965
1966                 if (tfile->detached)
1967                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
1968                 if (!tfile->socket.sk->sk_filter)
1969                         ifr.ifr_flags |= IFF_NOFILTER;
1970
1971                 if (copy_to_user(argp, &ifr, ifreq_len))
1972                         ret = -EFAULT;
1973                 break;
1974
1975         case TUNSETNOCSUM:
1976                 /* Disable/Enable checksum */
1977
1978                 /* [unimplemented] */
1979                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1980                           arg ? "disabled" : "enabled");
1981                 break;
1982
1983         case TUNSETPERSIST:
1984                 /* Disable/Enable persist mode. Keep an extra reference to the
1985                  * module to prevent the module being unprobed.
1986                  */
1987                 if (arg && !(tun->flags & IFF_PERSIST)) {
1988                         tun->flags |= IFF_PERSIST;
1989                         __module_get(THIS_MODULE);
1990                 }
1991                 if (!arg && (tun->flags & IFF_PERSIST)) {
1992                         tun->flags &= ~IFF_PERSIST;
1993                         module_put(THIS_MODULE);
1994                 }
1995
1996                 tun_debug(KERN_INFO, tun, "persist %s\n",
1997                           arg ? "enabled" : "disabled");
1998                 break;
1999
2000         case TUNSETOWNER:
2001                 /* Set owner of the device */
2002                 owner = make_kuid(current_user_ns(), arg);
2003                 if (!uid_valid(owner)) {
2004                         ret = -EINVAL;
2005                         break;
2006                 }
2007                 tun->owner = owner;
2008                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2009                           from_kuid(&init_user_ns, tun->owner));
2010                 break;
2011
2012         case TUNSETGROUP:
2013                 /* Set group of the device */
2014                 group = make_kgid(current_user_ns(), arg);
2015                 if (!gid_valid(group)) {
2016                         ret = -EINVAL;
2017                         break;
2018                 }
2019                 tun->group = group;
2020                 tun_debug(KERN_INFO, tun, "group set to %u\n",
2021                           from_kgid(&init_user_ns, tun->group));
2022                 break;
2023
2024         case TUNSETLINK:
2025                 /* Only allow setting the type when the interface is down */
2026                 if (tun->dev->flags & IFF_UP) {
2027                         tun_debug(KERN_INFO, tun,
2028                                   "Linktype set failed because interface is up\n");
2029                         ret = -EBUSY;
2030                 } else {
2031                         tun->dev->type = (int) arg;
2032                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2033                                   tun->dev->type);
2034                         ret = 0;
2035                 }
2036                 break;
2037
2038 #ifdef TUN_DEBUG
2039         case TUNSETDEBUG:
2040                 tun->debug = arg;
2041                 break;
2042 #endif
2043         case TUNSETOFFLOAD:
2044                 ret = set_offload(tun, arg);
2045                 break;
2046
2047         case TUNSETTXFILTER:
2048                 /* Can be set only for TAPs */
2049                 ret = -EINVAL;
2050                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2051                         break;
2052                 ret = update_filter(&tun->txflt, (void __user *)arg);
2053                 break;
2054
2055         case SIOCGIFHWADDR:
2056                 /* Get hw address */
2057                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2058                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2059                 if (copy_to_user(argp, &ifr, ifreq_len))
2060                         ret = -EFAULT;
2061                 break;
2062
2063         case SIOCSIFHWADDR:
2064                 /* Set hw address */
2065                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2066                           ifr.ifr_hwaddr.sa_data);
2067
2068                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2069                 break;
2070
2071         case TUNGETSNDBUF:
2072                 sndbuf = tfile->socket.sk->sk_sndbuf;
2073                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2074                         ret = -EFAULT;
2075                 break;
2076
2077         case TUNSETSNDBUF:
2078                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2079                         ret = -EFAULT;
2080                         break;
2081                 }
2082
2083                 tun->sndbuf = sndbuf;
2084                 tun_set_sndbuf(tun);
2085                 break;
2086
2087         case TUNGETVNETHDRSZ:
2088                 vnet_hdr_sz = tun->vnet_hdr_sz;
2089                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2090                         ret = -EFAULT;
2091                 break;
2092
2093         case TUNSETVNETHDRSZ:
2094                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2095                         ret = -EFAULT;
2096                         break;
2097                 }
2098                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2099                         ret = -EINVAL;
2100                         break;
2101                 }
2102
2103                 tun->vnet_hdr_sz = vnet_hdr_sz;
2104                 break;
2105
2106         case TUNGETVNETLE:
2107                 le = !!(tun->flags & TUN_VNET_LE);
2108                 if (put_user(le, (int __user *)argp))
2109                         ret = -EFAULT;
2110                 break;
2111
2112         case TUNSETVNETLE:
2113                 if (get_user(le, (int __user *)argp)) {
2114                         ret = -EFAULT;
2115                         break;
2116                 }
2117                 if (le)
2118                         tun->flags |= TUN_VNET_LE;
2119                 else
2120                         tun->flags &= ~TUN_VNET_LE;
2121                 break;
2122
2123         case TUNGETVNETBE:
2124                 ret = tun_get_vnet_be(tun, argp);
2125                 break;
2126
2127         case TUNSETVNETBE:
2128                 ret = tun_set_vnet_be(tun, argp);
2129                 break;
2130
2131         case TUNATTACHFILTER:
2132                 /* Can be set only for TAPs */
2133                 ret = -EINVAL;
2134                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2135                         break;
2136                 ret = -EFAULT;
2137                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2138                         break;
2139
2140                 ret = tun_attach_filter(tun);
2141                 break;
2142
2143         case TUNDETACHFILTER:
2144                 /* Can be set only for TAPs */
2145                 ret = -EINVAL;
2146                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2147                         break;
2148                 ret = 0;
2149                 tun_detach_filter(tun, tun->numqueues);
2150                 break;
2151
2152         case TUNGETFILTER:
2153                 ret = -EINVAL;
2154                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2155                         break;
2156                 ret = -EFAULT;
2157                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2158                         break;
2159                 ret = 0;
2160                 break;
2161
2162         default:
2163                 ret = -EINVAL;
2164                 break;
2165         }
2166
2167 unlock:
2168         rtnl_unlock();
2169         if (tun)
2170                 tun_put(tun);
2171         return ret;
2172 }
2173
2174 static long tun_chr_ioctl(struct file *file,
2175                           unsigned int cmd, unsigned long arg)
2176 {
2177         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2178 }
2179
2180 #ifdef CONFIG_COMPAT
2181 static long tun_chr_compat_ioctl(struct file *file,
2182                          unsigned int cmd, unsigned long arg)
2183 {
2184         switch (cmd) {
2185         case TUNSETIFF:
2186         case TUNGETIFF:
2187         case TUNSETTXFILTER:
2188         case TUNGETSNDBUF:
2189         case TUNSETSNDBUF:
2190         case SIOCGIFHWADDR:
2191         case SIOCSIFHWADDR:
2192                 arg = (unsigned long)compat_ptr(arg);
2193                 break;
2194         default:
2195                 arg = (compat_ulong_t)arg;
2196                 break;
2197         }
2198
2199         /*
2200          * compat_ifreq is shorter than ifreq, so we must not access beyond
2201          * the end of that structure. All fields that are used in this
2202          * driver are compatible though, we don't need to convert the
2203          * contents.
2204          */
2205         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2206 }
2207 #endif /* CONFIG_COMPAT */
2208
2209 static int tun_chr_fasync(int fd, struct file *file, int on)
2210 {
2211         struct tun_file *tfile = file->private_data;
2212         int ret;
2213
2214         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2215                 goto out;
2216
2217         if (on) {
2218                 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2219                 tfile->flags |= TUN_FASYNC;
2220         } else
2221                 tfile->flags &= ~TUN_FASYNC;
2222         ret = 0;
2223 out:
2224         return ret;
2225 }
2226
2227 static int tun_chr_open(struct inode *inode, struct file * file)
2228 {
2229         struct net *net = current->nsproxy->net_ns;
2230         struct tun_file *tfile;
2231
2232         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2233
2234         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2235                                             &tun_proto, 0);
2236         if (!tfile)
2237                 return -ENOMEM;
2238         RCU_INIT_POINTER(tfile->tun, NULL);
2239         tfile->flags = 0;
2240         tfile->ifindex = 0;
2241
2242         init_waitqueue_head(&tfile->wq.wait);
2243         RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2244
2245         tfile->socket.file = file;
2246         tfile->socket.ops = &tun_socket_ops;
2247
2248         sock_init_data(&tfile->socket, &tfile->sk);
2249
2250         tfile->sk.sk_write_space = tun_sock_write_space;
2251         tfile->sk.sk_sndbuf = INT_MAX;
2252
2253         file->private_data = tfile;
2254         INIT_LIST_HEAD(&tfile->next);
2255
2256         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2257
2258         return 0;
2259 }
2260
2261 static int tun_chr_close(struct inode *inode, struct file *file)
2262 {
2263         struct tun_file *tfile = file->private_data;
2264
2265         tun_detach(tfile, true);
2266
2267         return 0;
2268 }
2269
2270 #ifdef CONFIG_PROC_FS
2271 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2272 {
2273         struct tun_struct *tun;
2274         struct ifreq ifr;
2275
2276         memset(&ifr, 0, sizeof(ifr));
2277
2278         rtnl_lock();
2279         tun = tun_get(f);
2280         if (tun)
2281                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2282         rtnl_unlock();
2283
2284         if (tun)
2285                 tun_put(tun);
2286
2287         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2288 }
2289 #endif
2290
2291 static const struct file_operations tun_fops = {
2292         .owner  = THIS_MODULE,
2293         .llseek = no_llseek,
2294         .read_iter  = tun_chr_read_iter,
2295         .write_iter = tun_chr_write_iter,
2296         .poll   = tun_chr_poll,
2297         .unlocked_ioctl = tun_chr_ioctl,
2298 #ifdef CONFIG_COMPAT
2299         .compat_ioctl = tun_chr_compat_ioctl,
2300 #endif
2301         .open   = tun_chr_open,
2302         .release = tun_chr_close,
2303         .fasync = tun_chr_fasync,
2304 #ifdef CONFIG_PROC_FS
2305         .show_fdinfo = tun_chr_show_fdinfo,
2306 #endif
2307 };
2308
2309 static struct miscdevice tun_miscdev = {
2310         .minor = TUN_MINOR,
2311         .name = "tun",
2312         .nodename = "net/tun",
2313         .fops = &tun_fops,
2314 };
2315
2316 /* ethtool interface */
2317
2318 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2319 {
2320         cmd->supported          = 0;
2321         cmd->advertising        = 0;
2322         ethtool_cmd_speed_set(cmd, SPEED_10);
2323         cmd->duplex             = DUPLEX_FULL;
2324         cmd->port               = PORT_TP;
2325         cmd->phy_address        = 0;
2326         cmd->transceiver        = XCVR_INTERNAL;
2327         cmd->autoneg            = AUTONEG_DISABLE;
2328         cmd->maxtxpkt           = 0;
2329         cmd->maxrxpkt           = 0;
2330         return 0;
2331 }
2332
2333 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2334 {
2335         struct tun_struct *tun = netdev_priv(dev);
2336
2337         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2338         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2339
2340         switch (tun->flags & TUN_TYPE_MASK) {
2341         case IFF_TUN:
2342                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2343                 break;
2344         case IFF_TAP:
2345                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2346                 break;
2347         }
2348 }
2349
2350 static u32 tun_get_msglevel(struct net_device *dev)
2351 {
2352 #ifdef TUN_DEBUG
2353         struct tun_struct *tun = netdev_priv(dev);
2354         return tun->debug;
2355 #else
2356         return -EOPNOTSUPP;
2357 #endif
2358 }
2359
2360 static void tun_set_msglevel(struct net_device *dev, u32 value)
2361 {
2362 #ifdef TUN_DEBUG
2363         struct tun_struct *tun = netdev_priv(dev);
2364         tun->debug = value;
2365 #endif
2366 }
2367
2368 static const struct ethtool_ops tun_ethtool_ops = {
2369         .get_settings   = tun_get_settings,
2370         .get_drvinfo    = tun_get_drvinfo,
2371         .get_msglevel   = tun_get_msglevel,
2372         .set_msglevel   = tun_set_msglevel,
2373         .get_link       = ethtool_op_get_link,
2374         .get_ts_info    = ethtool_op_get_ts_info,
2375 };
2376
2377
2378 static int __init tun_init(void)
2379 {
2380         int ret = 0;
2381
2382         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2383         pr_info("%s\n", DRV_COPYRIGHT);
2384
2385         ret = rtnl_link_register(&tun_link_ops);
2386         if (ret) {
2387                 pr_err("Can't register link_ops\n");
2388                 goto err_linkops;
2389         }
2390
2391         ret = misc_register(&tun_miscdev);
2392         if (ret) {
2393                 pr_err("Can't register misc device %d\n", TUN_MINOR);
2394                 goto err_misc;
2395         }
2396         return  0;
2397 err_misc:
2398         rtnl_link_unregister(&tun_link_ops);
2399 err_linkops:
2400         return ret;
2401 }
2402
2403 static void tun_cleanup(void)
2404 {
2405         misc_deregister(&tun_miscdev);
2406         rtnl_link_unregister(&tun_link_ops);
2407 }
2408
2409 /* Get an underlying socket object from tun file.  Returns error unless file is
2410  * attached to a device.  The returned object works like a packet socket, it
2411  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2412  * holding a reference to the file for as long as the socket is in use. */
2413 struct socket *tun_get_socket(struct file *file)
2414 {
2415         struct tun_file *tfile;
2416         if (file->f_op != &tun_fops)
2417                 return ERR_PTR(-EINVAL);
2418         tfile = file->private_data;
2419         if (!tfile)
2420                 return ERR_PTR(-EBADFD);
2421         return &tfile->socket;
2422 }
2423 EXPORT_SYMBOL_GPL(tun_get_socket);
2424
2425 module_init(tun_init);
2426 module_exit(tun_cleanup);
2427 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2428 MODULE_AUTHOR(DRV_COPYRIGHT);
2429 MODULE_LICENSE("GPL");
2430 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2431 MODULE_ALIAS("devname:net/tun");