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