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/ipv6.h>
  69 #include <net/net_namespace.h>
  70 #include <net/netns/generic.h>
  71 #include <net/rtnetlink.h>
  72 #include <net/sock.h>
  73 #include <linux/seq_file.h>
  74 #include <linux/uio.h>
  75
  76 #include <asm/uaccess.h>
  77
  78 /* Uncomment to enable debugging */
  79 /* #define TUN_DEBUG 1 */
  80
  81 #ifdef TUN_DEBUG
  82 static int debug;
  83
  84 #define tun_debug(level, tun, fmt, args...)                     \
  85 do {                                                            \
  86         if (tun->debug)                                         \
  87                 netdev_printk(level, tun->dev, fmt, ##args);    \
  88 } while (0)
  89 #define DBG1(level, fmt, args...)                               \
  90 do {                                                            \
  91         if (debug == 2)                                         \
  92                 printk(level fmt, ##args);                      \
  93 } while (0)
  94 #else
  95 #define tun_debug(level, tun, fmt, args...)                     \
  96 do {                                                            \
  97         if (0)                                                  \
  98                 netdev_printk(level, tun->dev, fmt, ##args);    \
  99 } while (0)
 100 #define DBG1(level, fmt, args...)                               \
 101 do {                                                            \
 102         if (0)                                                  \
 103                 printk(level fmt, ##args);                      \
 104 } while (0)
 105 #endif
 106
 107 /* TUN device flags */
 108
 109 /* IFF_ATTACH_QUEUE is never stored in device flags,
 110  * overload it to mean fasync when stored there.
 111  */
 112 #define TUN_FASYNC      IFF_ATTACH_QUEUE
 113
 114 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
 115                       IFF_VNET_LE | IFF_MULTI_QUEUE)
 116 #define GOODCOPY_LEN 128
 117
 118 #define FLT_EXACT_COUNT 8
 119 struct tap_filter {
 120         unsigned int    count;    /* Number of addrs. Zero means disabled */
 121         u32             mask[2];  /* Mask of the hashed addrs */
 122         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 123 };
 124
 125 /* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for
 126  * the netdevice to be fit in one page. So we can make sure the success of
 127  * memory allocation. TODO: increase the limit. */
 128 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES
 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 net *net;
 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)
 189
 190         int                     vnet_hdr_sz;
 191         int                     sndbuf;
 192         struct tap_filter       txflt;
 193         struct sock_fprog       fprog;
 194         /* protected by rtnl lock */
 195         bool                    filter_attached;
 196 #ifdef TUN_DEBUG
 197         int debug;
 198 #endif
 199         spinlock_t lock;
 200         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 201         struct timer_list flow_gc_timer;
 202         unsigned long ageing_time;
 203         unsigned int numdisabled;
 204         struct list_head disabled;
 205         void *security;
 206         u32 flow_count;
 207 };
 208
 209 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
 210 {
 211         return __virtio16_to_cpu(tun->flags & IFF_VNET_LE, val);
 212 }
 213
 214 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
 215 {
 216         return __cpu_to_virtio16(tun->flags & IFF_VNET_LE, val);
 217 }
 218
 219 static inline u32 tun_hashfn(u32 rxhash)
 220 {
 221         return rxhash & 0x3ff;
 222 }
 223
 224 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 225 {
 226         struct tun_flow_entry *e;
 227
 228         hlist_for_each_entry_rcu(e, head, hash_link) {
 229                 if (e->rxhash == rxhash)
 230                         return e;
 231         }
 232         return NULL;
 233 }
 234
 235 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 236                                               struct hlist_head *head,
 237                                               u32 rxhash, u16 queue_index)
 238 {
 239         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 240
 241         if (e) {
 242                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 243                           rxhash, queue_index);
 244                 e->updated = jiffies;
 245                 e->rxhash = rxhash;
 246                 e->rps_rxhash = 0;
 247                 e->queue_index = queue_index;
 248                 e->tun = tun;
 249                 hlist_add_head_rcu(&e->hash_link, head);
 250                 ++tun->flow_count;
 251         }
 252         return e;
 253 }
 254
 255 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 256 {
 257         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 258                   e->rxhash, e->queue_index);
 259         sock_rps_reset_flow_hash(e->rps_rxhash);
 260         hlist_del_rcu(&e->hash_link);
 261         kfree_rcu(e, rcu);
 262         --tun->flow_count;
 263 }
 264
 265 static void tun_flow_flush(struct tun_struct *tun)
 266 {
 267         int i;
 268
 269         spin_lock_bh(&tun->lock);
 270         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 271                 struct tun_flow_entry *e;
 272                 struct hlist_node *n;
 273
 274                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 275                         tun_flow_delete(tun, e);
 276         }
 277         spin_unlock_bh(&tun->lock);
 278 }
 279
 280 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 281 {
 282         int i;
 283
 284         spin_lock_bh(&tun->lock);
 285         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 286                 struct tun_flow_entry *e;
 287                 struct hlist_node *n;
 288
 289                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 290                         if (e->queue_index == queue_index)
 291                                 tun_flow_delete(tun, e);
 292                 }
 293         }
 294         spin_unlock_bh(&tun->lock);
 295 }
 296
 297 static void tun_flow_cleanup(unsigned long data)
 298 {
 299         struct tun_struct *tun = (struct tun_struct *)data;
 300         unsigned long delay = tun->ageing_time;
 301         unsigned long next_timer = jiffies + delay;
 302         unsigned long count = 0;
 303         int i;
 304
 305         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 306
 307         spin_lock_bh(&tun->lock);
 308         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 309                 struct tun_flow_entry *e;
 310                 struct hlist_node *n;
 311
 312                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 313                         unsigned long this_timer;
 314                         count++;
 315                         this_timer = e->updated + delay;
 316                         if (time_before_eq(this_timer, jiffies))
 317                                 tun_flow_delete(tun, e);
 318                         else if (time_before(this_timer, next_timer))
 319                                 next_timer = this_timer;
 320                 }
 321         }
 322
 323         if (count)
 324                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 325         spin_unlock_bh(&tun->lock);
 326 }
 327
 328 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 329                             struct tun_file *tfile)
 330 {
 331         struct hlist_head *head;
 332         struct tun_flow_entry *e;
 333         unsigned long delay = tun->ageing_time;
 334         u16 queue_index = tfile->queue_index;
 335
 336         if (!rxhash)
 337                 return;
 338         else
 339                 head = &tun->flows[tun_hashfn(rxhash)];
 340
 341         rcu_read_lock();
 342
 343         /* We may get a very small possibility of OOO during switching, not
 344          * worth to optimize.*/
 345         if (tun->numqueues == 1 || tfile->detached)
 346                 goto unlock;
 347
 348         e = tun_flow_find(head, rxhash);
 349         if (likely(e)) {
 350                 /* TODO: keep queueing to old queue until it's empty? */
 351                 e->queue_index = queue_index;
 352                 e->updated = jiffies;
 353                 sock_rps_record_flow_hash(e->rps_rxhash);
 354         } else {
 355                 spin_lock_bh(&tun->lock);
 356                 if (!tun_flow_find(head, rxhash) &&
 357                     tun->flow_count < MAX_TAP_FLOWS)
 358                         tun_flow_create(tun, head, rxhash, queue_index);
 359
 360                 if (!timer_pending(&tun->flow_gc_timer))
 361                         mod_timer(&tun->flow_gc_timer,
 362                                   round_jiffies_up(jiffies + delay));
 363                 spin_unlock_bh(&tun->lock);
 364         }
 365
 366 unlock:
 367         rcu_read_unlock();
 368 }
 369
 370 /**
 371  * Save the hash received in the stack receive path and update the
 372  * flow_hash table accordingly.
 373  */
 374 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
 375 {
 376         if (unlikely(e->rps_rxhash != hash)) {
 377                 sock_rps_reset_flow_hash(e->rps_rxhash);
 378                 e->rps_rxhash = hash;
 379         }
 380 }
 381
 382 /* We try to identify a flow through its rxhash first. The reason that
 383  * we do not check rxq no. is because some cards(e.g 82599), chooses
 384  * the rxq based on the txq where the last packet of the flow comes. As
 385  * the userspace application move between processors, we may get a
 386  * different rxq no. here. If we could not get rxhash, then we would
 387  * hope the rxq no. may help here.
 388  */
 389 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
 390                             void *accel_priv, select_queue_fallback_t fallback)
 391 {
 392         struct tun_struct *tun = netdev_priv(dev);
 393         struct tun_flow_entry *e;
 394         u32 txq = 0;
 395         u32 numqueues = 0;
 396
 397         rcu_read_lock();
 398         numqueues = ACCESS_ONCE(tun->numqueues);
 399
 400         txq = skb_get_hash(skb);
 401         if (txq) {
 402                 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 403                 if (e) {
 404                         tun_flow_save_rps_rxhash(e, txq);
 405                         txq = e->queue_index;
 406                 } else
 407                         /* use multiply and shift instead of expensive divide */
 408                         txq = ((u64)txq * numqueues) >> 32;
 409         } else if (likely(skb_rx_queue_recorded(skb))) {
 410                 txq = skb_get_rx_queue(skb);
 411                 while (unlikely(txq >= numqueues))
 412                         txq -= numqueues;
 413         }
 414
 415         rcu_read_unlock();
 416         return txq;
 417 }
 418
 419 static inline bool tun_not_capable(struct tun_struct *tun)
 420 {
 421         const struct cred *cred = current_cred();
 422         struct net *net = dev_net(tun->dev);
 423
 424         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 425                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 426                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 427 }
 428
 429 static void tun_set_real_num_queues(struct tun_struct *tun)
 430 {
 431         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 432         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 433 }
 434
 435 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 436 {
 437         tfile->detached = tun;
 438         list_add_tail(&tfile->next, &tun->disabled);
 439         ++tun->numdisabled;
 440 }
 441
 442 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 443 {
 444         struct tun_struct *tun = tfile->detached;
 445
 446         tfile->detached = NULL;
 447         list_del_init(&tfile->next);
 448         --tun->numdisabled;
 449         return tun;
 450 }
 451
 452 static void tun_queue_purge(struct tun_file *tfile)
 453 {
 454         skb_queue_purge(&tfile->sk.sk_receive_queue);
 455         skb_queue_purge(&tfile->sk.sk_error_queue);
 456 }
 457
 458 static void __tun_detach(struct tun_file *tfile, bool clean)
 459 {
 460         struct tun_file *ntfile;
 461         struct tun_struct *tun;
 462
 463         tun = rtnl_dereference(tfile->tun);
 464
 465         if (tun && !tfile->detached) {
 466                 u16 index = tfile->queue_index;
 467                 BUG_ON(index >= tun->numqueues);
 468
 469                 rcu_assign_pointer(tun->tfiles[index],
 470                                    tun->tfiles[tun->numqueues - 1]);
 471                 ntfile = rtnl_dereference(tun->tfiles[index]);
 472                 ntfile->queue_index = index;
 473
 474                 --tun->numqueues;
 475                 if (clean) {
 476                         RCU_INIT_POINTER(tfile->tun, NULL);
 477                         sock_put(&tfile->sk);
 478                 } else
 479                         tun_disable_queue(tun, tfile);
 480
 481                 synchronize_net();
 482                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 483                 /* Drop read queue */
 484                 tun_queue_purge(tfile);
 485                 tun_set_real_num_queues(tun);
 486         } else if (tfile->detached && clean) {
 487                 tun = tun_enable_queue(tfile);
 488                 sock_put(&tfile->sk);
 489         }
 490
 491         if (clean) {
 492                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 493                         netif_carrier_off(tun->dev);
 494
 495                         if (!(tun->flags & IFF_PERSIST) &&
 496                             tun->dev->reg_state == NETREG_REGISTERED)
 497                                 unregister_netdevice(tun->dev);
 498                 }
 499
 500                 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
 501                                  &tfile->socket.flags));
 502                 sk_release_kernel(&tfile->sk);
 503         }
 504 }
 505
 506 static void tun_detach(struct tun_file *tfile, bool clean)
 507 {
 508         rtnl_lock();
 509         __tun_detach(tfile, clean);
 510         rtnl_unlock();
 511 }
 512
 513 static void tun_detach_all(struct net_device *dev)
 514 {
 515         struct tun_struct *tun = netdev_priv(dev);
 516         struct tun_file *tfile, *tmp;
 517         int i, n = tun->numqueues;
 518
 519         for (i = 0; i < n; i++) {
 520                 tfile = rtnl_dereference(tun->tfiles[i]);
 521                 BUG_ON(!tfile);
 522                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 523                 RCU_INIT_POINTER(tfile->tun, NULL);
 524                 --tun->numqueues;
 525         }
 526         list_for_each_entry(tfile, &tun->disabled, next) {
 527                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 528                 RCU_INIT_POINTER(tfile->tun, NULL);
 529         }
 530         BUG_ON(tun->numqueues != 0);
 531
 532         synchronize_net();
 533         for (i = 0; i < n; i++) {
 534                 tfile = rtnl_dereference(tun->tfiles[i]);
 535                 /* Drop read queue */
 536                 tun_queue_purge(tfile);
 537                 sock_put(&tfile->sk);
 538         }
 539         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 540                 tun_enable_queue(tfile);
 541                 tun_queue_purge(tfile);
 542                 sock_put(&tfile->sk);
 543         }
 544         BUG_ON(tun->numdisabled != 0);
 545
 546         if (tun->flags & IFF_PERSIST)
 547                 module_put(THIS_MODULE);
 548 }
 549
 550 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
 551 {
 552         struct tun_file *tfile = file->private_data;
 553         int err;
 554
 555         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 556         if (err < 0)
 557                 goto out;
 558
 559         err = -EINVAL;
 560         if (rtnl_dereference(tfile->tun) && !tfile->detached)
 561                 goto out;
 562
 563         err = -EBUSY;
 564         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
 565                 goto out;
 566
 567         err = -E2BIG;
 568         if (!tfile->detached &&
 569             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 570                 goto out;
 571
 572         err = 0;
 573
 574         /* Re-attach the filter to persist device */
 575         if (!skip_filter && (tun->filter_attached == true)) {
 576                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 577                 if (!err)
 578                         goto out;
 579         }
 580         tfile->queue_index = tun->numqueues;
 581         rcu_assign_pointer(tfile->tun, tun);
 582         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 583         tun->numqueues++;
 584
 585         if (tfile->detached)
 586                 tun_enable_queue(tfile);
 587         else
 588                 sock_hold(&tfile->sk);
 589
 590         tun_set_real_num_queues(tun);
 591
 592         /* device is allowed to go away first, so no need to hold extra
 593          * refcnt.
 594          */
 595
 596 out:
 597         return err;
 598 }
 599
 600 static struct tun_struct *__tun_get(struct tun_file *tfile)
 601 {
 602         struct tun_struct *tun;
 603
 604         rcu_read_lock();
 605         tun = rcu_dereference(tfile->tun);
 606         if (tun)
 607                 dev_hold(tun->dev);
 608         rcu_read_unlock();
 609
 610         return tun;
 611 }
 612
 613 static struct tun_struct *tun_get(struct file *file)
 614 {
 615         return __tun_get(file->private_data);
 616 }
 617
 618 static void tun_put(struct tun_struct *tun)
 619 {
 620         dev_put(tun->dev);
 621 }
 622
 623 /* TAP filtering */
 624 static void addr_hash_set(u32 *mask, const u8 *addr)
 625 {
 626         int n = ether_crc(ETH_ALEN, addr) >> 26;
 627         mask[n >> 5] |= (1 << (n & 31));
 628 }
 629
 630 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 631 {
 632         int n = ether_crc(ETH_ALEN, addr) >> 26;
 633         return mask[n >> 5] & (1 << (n & 31));
 634 }
 635
 636 static int update_filter(struct tap_filter *filter, void __user *arg)
 637 {
 638         struct { u8 u[ETH_ALEN]; } *addr;
 639         struct tun_filter uf;
 640         int err, alen, n, nexact;
 641
 642         if (copy_from_user(&uf, arg, sizeof(uf)))
 643                 return -EFAULT;
 644
 645         if (!uf.count) {
 646                 /* Disabled */
 647                 filter->count = 0;
 648                 return 0;
 649         }
 650
 651         alen = ETH_ALEN * uf.count;
 652         addr = kmalloc(alen, GFP_KERNEL);
 653         if (!addr)
 654                 return -ENOMEM;
 655
 656         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 657                 err = -EFAULT;
 658                 goto done;
 659         }
 660
 661         /* The filter is updated without holding any locks. Which is
 662          * perfectly safe. We disable it first and in the worst
 663          * case we'll accept a few undesired packets. */
 664         filter->count = 0;
 665         wmb();
 666
 667         /* Use first set of addresses as an exact filter */
 668         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 669                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 670
 671         nexact = n;
 672
 673         /* Remaining multicast addresses are hashed,
 674          * unicast will leave the filter disabled. */
 675         memset(filter->mask, 0, sizeof(filter->mask));
 676         for (; n < uf.count; n++) {
 677                 if (!is_multicast_ether_addr(addr[n].u)) {
 678                         err = 0; /* no filter */
 679                         goto done;
 680                 }
 681                 addr_hash_set(filter->mask, addr[n].u);
 682         }
 683
 684         /* For ALLMULTI just set the mask to all ones.
 685          * This overrides the mask populated above. */
 686         if ((uf.flags & TUN_FLT_ALLMULTI))
 687                 memset(filter->mask, ~0, sizeof(filter->mask));
 688
 689         /* Now enable the filter */
 690         wmb();
 691         filter->count = nexact;
 692
 693         /* Return the number of exact filters */
 694         err = nexact;
 695
 696 done:
 697         kfree(addr);
 698         return err;
 699 }
 700
 701 /* Returns: 0 - drop, !=0 - accept */
 702 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 703 {
 704         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 705          * at this point. */
 706         struct ethhdr *eh = (struct ethhdr *) skb->data;
 707         int i;
 708
 709         /* Exact match */
 710         for (i = 0; i < filter->count; i++)
 711                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 712                         return 1;
 713
 714         /* Inexact match (multicast only) */
 715         if (is_multicast_ether_addr(eh->h_dest))
 716                 return addr_hash_test(filter->mask, eh->h_dest);
 717
 718         return 0;
 719 }
 720
 721 /*
 722  * Checks whether the packet is accepted or not.
 723  * Returns: 0 - drop, !=0 - accept
 724  */
 725 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 726 {
 727         if (!filter->count)
 728                 return 1;
 729
 730         return run_filter(filter, skb);
 731 }
 732
 733 /* Network device part of the driver */
 734
 735 static const struct ethtool_ops tun_ethtool_ops;
 736
 737 /* Net device detach from fd. */
 738 static void tun_net_uninit(struct net_device *dev)
 739 {
 740         tun_detach_all(dev);
 741 }
 742
 743 /* Net device open. */
 744 static int tun_net_open(struct net_device *dev)
 745 {
 746         netif_tx_start_all_queues(dev);
 747         return 0;
 748 }
 749
 750 /* Net device close. */
 751 static int tun_net_close(struct net_device *dev)
 752 {
 753         netif_tx_stop_all_queues(dev);
 754         return 0;
 755 }
 756
 757 /* Net device start xmit */
 758 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 759 {
 760         struct tun_struct *tun = netdev_priv(dev);
 761         int txq = skb->queue_mapping;
 762         struct tun_file *tfile;
 763         u32 numqueues = 0;
 764
 765         rcu_read_lock();
 766         tfile = rcu_dereference(tun->tfiles[txq]);
 767         numqueues = ACCESS_ONCE(tun->numqueues);
 768
 769         /* Drop packet if interface is not attached */
 770         if (txq >= numqueues)
 771                 goto drop;
 772
 773         if (numqueues == 1) {
 774                 /* Select queue was not called for the skbuff, so we extract the
 775                  * RPS hash and save it into the flow_table here.
 776                  */
 777                 __u32 rxhash;
 778
 779                 rxhash = skb_get_hash(skb);
 780                 if (rxhash) {
 781                         struct tun_flow_entry *e;
 782                         e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
 783                                         rxhash);
 784                         if (e)
 785                                 tun_flow_save_rps_rxhash(e, rxhash);
 786                 }
 787         }
 788
 789         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 790
 791         BUG_ON(!tfile);
 792
 793         /* Drop if the filter does not like it.
 794          * This is a noop if the filter is disabled.
 795          * Filter can be enabled only for the TAP devices. */
 796         if (!check_filter(&tun->txflt, skb))
 797                 goto drop;
 798
 799         if (tfile->socket.sk->sk_filter &&
 800             sk_filter(tfile->socket.sk, skb))
 801                 goto drop;
 802
 803         /* Limit the number of packets queued by dividing txq length with the
 804          * number of queues.
 805          */
 806         if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues
 807                           >= dev->tx_queue_len)
 808                 goto drop;
 809
 810         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 811                 goto drop;
 812
 813         if (skb->sk) {
 814                 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags);
 815                 sw_tx_timestamp(skb);
 816         }
 817
 818         /* Orphan the skb - required as we might hang on to it
 819          * for indefinite time.
 820          */
 821         skb_orphan(skb);
 822
 823         nf_reset(skb);
 824
 825         /* Enqueue packet */
 826         skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
 827
 828         /* Notify and wake up reader process */
 829         if (tfile->flags & TUN_FASYNC)
 830                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
 831         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 832
 833         rcu_read_unlock();
 834         return NETDEV_TX_OK;
 835
 836 drop:
 837         dev->stats.tx_dropped++;
 838         skb_tx_error(skb);
 839         kfree_skb(skb);
 840         rcu_read_unlock();
 841         return NET_XMIT_DROP;
 842 }
 843
 844 static void tun_net_mclist(struct net_device *dev)
 845 {
 846         /*
 847          * This callback is supposed to deal with mc filter in
 848          * _rx_ path and has nothing to do with the _tx_ path.
 849          * In rx path we always accept everything userspace gives us.
 850          */
 851 }
 852
 853 #define MIN_MTU 68
 854 #define MAX_MTU 65535
 855
 856 static int
 857 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 858 {
 859         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 860                 return -EINVAL;
 861         dev->mtu = new_mtu;
 862         return 0;
 863 }
 864
 865 static netdev_features_t tun_net_fix_features(struct net_device *dev,
 866         netdev_features_t features)
 867 {
 868         struct tun_struct *tun = netdev_priv(dev);
 869
 870         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 871 }
 872 #ifdef CONFIG_NET_POLL_CONTROLLER
 873 static void tun_poll_controller(struct net_device *dev)
 874 {
 875         /*
 876          * Tun only receives frames when:
 877          * 1) the char device endpoint gets data from user space
 878          * 2) the tun socket gets a sendmsg call from user space
 879          * Since both of those are synchronous operations, we are guaranteed
 880          * never to have pending data when we poll for it
 881          * so there is nothing to do here but return.
 882          * We need this though so netpoll recognizes us as an interface that
 883          * supports polling, which enables bridge devices in virt setups to
 884          * still use netconsole
 885          */
 886         return;
 887 }
 888 #endif
 889 static const struct net_device_ops tun_netdev_ops = {
 890         .ndo_uninit             = tun_net_uninit,
 891         .ndo_open               = tun_net_open,
 892         .ndo_stop               = tun_net_close,
 893         .ndo_start_xmit         = tun_net_xmit,
 894         .ndo_change_mtu         = tun_net_change_mtu,
 895         .ndo_fix_features       = tun_net_fix_features,
 896         .ndo_select_queue       = tun_select_queue,
 897 #ifdef CONFIG_NET_POLL_CONTROLLER
 898         .ndo_poll_controller    = tun_poll_controller,
 899 #endif
 900 };
 901
 902 static const struct net_device_ops tap_netdev_ops = {
 903         .ndo_uninit             = tun_net_uninit,
 904         .ndo_open               = tun_net_open,
 905         .ndo_stop               = tun_net_close,
 906         .ndo_start_xmit         = tun_net_xmit,
 907         .ndo_change_mtu         = tun_net_change_mtu,
 908         .ndo_fix_features       = tun_net_fix_features,
 909         .ndo_set_rx_mode        = tun_net_mclist,
 910         .ndo_set_mac_address    = eth_mac_addr,
 911         .ndo_validate_addr      = eth_validate_addr,
 912         .ndo_select_queue       = tun_select_queue,
 913 #ifdef CONFIG_NET_POLL_CONTROLLER
 914         .ndo_poll_controller    = tun_poll_controller,
 915 #endif
 916 };
 917
 918 static void tun_flow_init(struct tun_struct *tun)
 919 {
 920         int i;
 921
 922         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
 923                 INIT_HLIST_HEAD(&tun->flows[i]);
 924
 925         tun->ageing_time = TUN_FLOW_EXPIRE;
 926         setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
 927         mod_timer(&tun->flow_gc_timer,
 928                   round_jiffies_up(jiffies + tun->ageing_time));
 929 }
 930
 931 static void tun_flow_uninit(struct tun_struct *tun)
 932 {
 933         del_timer_sync(&tun->flow_gc_timer);
 934         tun_flow_flush(tun);
 935 }
 936
 937 /* Initialize net device. */
 938 static void tun_net_init(struct net_device *dev)
 939 {
 940         struct tun_struct *tun = netdev_priv(dev);
 941
 942         switch (tun->flags & TUN_TYPE_MASK) {
 943         case IFF_TUN:
 944                 dev->netdev_ops = &tun_netdev_ops;
 945
 946                 /* Point-to-Point TUN Device */
 947                 dev->hard_header_len = 0;
 948                 dev->addr_len = 0;
 949                 dev->mtu = 1500;
 950
 951                 /* Zero header length */
 952                 dev->type = ARPHRD_NONE;
 953                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 954                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 955                 break;
 956
 957         case IFF_TAP:
 958                 dev->netdev_ops = &tap_netdev_ops;
 959                 /* Ethernet TAP Device */
 960                 ether_setup(dev);
 961                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 962                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
 963
 964                 eth_hw_addr_random(dev);
 965
 966                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 967                 break;
 968         }
 969 }
 970
 971 /* Character device part */
 972
 973 /* Poll */
 974 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
 975 {
 976         struct tun_file *tfile = file->private_data;
 977         struct tun_struct *tun = __tun_get(tfile);
 978         struct sock *sk;
 979         unsigned int mask = 0;
 980
 981         if (!tun)
 982                 return POLLERR;
 983
 984         sk = tfile->socket.sk;
 985
 986         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
 987
 988         poll_wait(file, sk_sleep(sk), wait);
 989
 990         if (!skb_queue_empty(&sk->sk_receive_queue))
 991                 mask |= POLLIN | POLLRDNORM;
 992
 993         if (sock_writeable(sk) ||
 994             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 995              sock_writeable(sk)))
 996                 mask |= POLLOUT | POLLWRNORM;
 997
 998         if (tun->dev->reg_state != NETREG_REGISTERED)
 999                 mask = POLLERR;
1000
1001         tun_put(tun);
1002         return mask;
1003 }
1004
1005 /* prepad is the amount to reserve at front.  len is length after that.
1006  * linear is a hint as to how much to copy (usually headers). */
1007 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1008                                      size_t prepad, size_t len,
1009                                      size_t linear, int noblock)
1010 {
1011         struct sock *sk = tfile->socket.sk;
1012         struct sk_buff *skb;
1013         int err;
1014
1015         /* Under a page?  Don't bother with paged skb. */
1016         if (prepad + len < PAGE_SIZE || !linear)
1017                 linear = len;
1018
1019         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1020                                    &err, 0);
1021         if (!skb)
1022                 return ERR_PTR(err);
1023
1024         skb_reserve(skb, prepad);
1025         skb_put(skb, linear);
1026         skb->data_len = len - linear;
1027         skb->len += len - linear;
1028
1029         return skb;
1030 }
1031
1032 /* Get packet from user space buffer */
1033 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1034                             void *msg_control, struct iov_iter *from,
1035                             int noblock)
1036 {
1037         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1038         struct sk_buff *skb;
1039         size_t total_len = iov_iter_count(from);
1040         size_t len = total_len, align = NET_SKB_PAD, linear;
1041         struct virtio_net_hdr gso = { 0 };
1042         int good_linear;
1043         int copylen;
1044         bool zerocopy = false;
1045         int err;
1046         u32 rxhash;
1047         ssize_t n;
1048
1049         if (!(tun->flags & IFF_NO_PI)) {
1050                 if (len < sizeof(pi))
1051                         return -EINVAL;
1052                 len -= sizeof(pi);
1053
1054                 n = copy_from_iter(&pi, sizeof(pi), from);
1055                 if (n != sizeof(pi))
1056                         return -EFAULT;
1057         }
1058
1059         if (tun->flags & IFF_VNET_HDR) {
1060                 if (len < tun->vnet_hdr_sz)
1061                         return -EINVAL;
1062                 len -= tun->vnet_hdr_sz;
1063
1064                 n = copy_from_iter(&gso, sizeof(gso), from);
1065                 if (n != sizeof(gso))
1066                         return -EFAULT;
1067
1068                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1069                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1070                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1071
1072                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1073                         return -EINVAL;
1074                 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso));
1075         }
1076
1077         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1078                 align += NET_IP_ALIGN;
1079                 if (unlikely(len < ETH_HLEN ||
1080                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1081                         return -EINVAL;
1082         }
1083
1084         good_linear = SKB_MAX_HEAD(align);
1085
1086         if (msg_control) {
1087                 struct iov_iter i = *from;
1088
1089                 /* There are 256 bytes to be copied in skb, so there is
1090                  * enough room for skb expand head in case it is used.
1091                  * The rest of the buffer is mapped from userspace.
1092                  */
1093                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1094                 if (copylen > good_linear)
1095                         copylen = good_linear;
1096                 linear = copylen;
1097                 iov_iter_advance(&i, copylen);
1098                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1099                         zerocopy = true;
1100         }
1101
1102         if (!zerocopy) {
1103                 copylen = len;
1104                 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1105                         linear = good_linear;
1106                 else
1107                         linear = tun16_to_cpu(tun, gso.hdr_len);
1108         }
1109
1110         skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1111         if (IS_ERR(skb)) {
1112                 if (PTR_ERR(skb) != -EAGAIN)
1113                         tun->dev->stats.rx_dropped++;
1114                 return PTR_ERR(skb);
1115         }
1116
1117         if (zerocopy)
1118                 err = zerocopy_sg_from_iter(skb, from);
1119         else {
1120                 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1121                 if (!err && msg_control) {
1122                         struct ubuf_info *uarg = msg_control;
1123                         uarg->callback(uarg, false);
1124                 }
1125         }
1126
1127         if (err) {
1128                 tun->dev->stats.rx_dropped++;
1129                 kfree_skb(skb);
1130                 return -EFAULT;
1131         }
1132
1133         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1134                 if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start),
1135                                           tun16_to_cpu(tun, gso.csum_offset))) {
1136                         tun->dev->stats.rx_frame_errors++;
1137                         kfree_skb(skb);
1138                         return -EINVAL;
1139                 }
1140         }
1141
1142         switch (tun->flags & TUN_TYPE_MASK) {
1143         case IFF_TUN:
1144                 if (tun->flags & IFF_NO_PI) {
1145                         switch (skb->data[0] & 0xf0) {
1146                         case 0x40:
1147                                 pi.proto = htons(ETH_P_IP);
1148                                 break;
1149                         case 0x60:
1150                                 pi.proto = htons(ETH_P_IPV6);
1151                                 break;
1152                         default:
1153                                 tun->dev->stats.rx_dropped++;
1154                                 kfree_skb(skb);
1155                                 return -EINVAL;
1156                         }
1157                 }
1158
1159                 skb_reset_mac_header(skb);
1160                 skb->protocol = pi.proto;
1161                 skb->dev = tun->dev;
1162                 break;
1163         case IFF_TAP:
1164                 skb->protocol = eth_type_trans(skb, tun->dev);
1165                 break;
1166         }
1167
1168         skb_reset_network_header(skb);
1169
1170         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1171                 pr_debug("GSO!\n");
1172                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1173                 case VIRTIO_NET_HDR_GSO_TCPV4:
1174                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1175                         break;
1176                 case VIRTIO_NET_HDR_GSO_TCPV6:
1177                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1178                         break;
1179                 case VIRTIO_NET_HDR_GSO_UDP:
1180                 {
1181                         static bool warned;
1182
1183                         if (!warned) {
1184                                 warned = true;
1185                                 netdev_warn(tun->dev,
1186                                             "%s: using disabled UFO feature; please fix this program\n",
1187                                             current->comm);
1188                         }
1189                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1190                         if (skb->protocol == htons(ETH_P_IPV6))
1191                                 ipv6_proxy_select_ident(skb);
1192                         break;
1193                 }
1194                 default:
1195                         tun->dev->stats.rx_frame_errors++;
1196                         kfree_skb(skb);
1197                         return -EINVAL;
1198                 }
1199
1200                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1201                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1202
1203                 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size);
1204                 if (skb_shinfo(skb)->gso_size == 0) {
1205                         tun->dev->stats.rx_frame_errors++;
1206                         kfree_skb(skb);
1207                         return -EINVAL;
1208                 }
1209
1210                 /* Header must be checked, and gso_segs computed. */
1211                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1212                 skb_shinfo(skb)->gso_segs = 0;
1213         }
1214
1215         /* copy skb_ubuf_info for callback when skb has no error */
1216         if (zerocopy) {
1217                 skb_shinfo(skb)->destructor_arg = msg_control;
1218                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1219                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1220         }
1221
1222         skb_probe_transport_header(skb, 0);
1223
1224         rxhash = skb_get_hash(skb);
1225         netif_rx_ni(skb);
1226
1227         tun->dev->stats.rx_packets++;
1228         tun->dev->stats.rx_bytes += len;
1229
1230         tun_flow_update(tun, rxhash, tfile);
1231         return total_len;
1232 }
1233
1234 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1235 {
1236         struct file *file = iocb->ki_filp;
1237         struct tun_struct *tun = tun_get(file);
1238         struct tun_file *tfile = file->private_data;
1239         ssize_t result;
1240
1241         if (!tun)
1242                 return -EBADFD;
1243
1244         result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);
1245
1246         tun_put(tun);
1247         return result;
1248 }
1249
1250 /* Put packet to the user space buffer */
1251 static ssize_t tun_put_user(struct tun_struct *tun,
1252                             struct tun_file *tfile,
1253                             struct sk_buff *skb,
1254                             struct iov_iter *iter)
1255 {
1256         struct tun_pi pi = { 0, skb->protocol };
1257         ssize_t total;
1258         int vlan_offset = 0;
1259         int vlan_hlen = 0;
1260         int vnet_hdr_sz = 0;
1261
1262         if (vlan_tx_tag_present(skb))
1263                 vlan_hlen = VLAN_HLEN;
1264
1265         if (tun->flags & IFF_VNET_HDR)
1266                 vnet_hdr_sz = tun->vnet_hdr_sz;
1267
1268         total = skb->len + vlan_hlen + vnet_hdr_sz;
1269
1270         if (!(tun->flags & IFF_NO_PI)) {
1271                 if (iov_iter_count(iter) < sizeof(pi))
1272                         return -EINVAL;
1273
1274                 total += sizeof(pi);
1275                 if (iov_iter_count(iter) < total) {
1276                         /* Packet will be striped */
1277                         pi.flags |= TUN_PKT_STRIP;
1278                 }
1279
1280                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1281                         return -EFAULT;
1282         }
1283
1284         if (vnet_hdr_sz) {
1285                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1286                 if (iov_iter_count(iter) < vnet_hdr_sz)
1287                         return -EINVAL;
1288
1289                 if (skb_is_gso(skb)) {
1290                         struct skb_shared_info *sinfo = skb_shinfo(skb);
1291
1292                         /* This is a hint as to how much should be linear. */
1293                         gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb));
1294                         gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size);
1295                         if (sinfo->gso_type & SKB_GSO_TCPV4)
1296                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1297                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
1298                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1299                         else {
1300                                 pr_err("unexpected GSO type: "
1301                                        "0x%x, gso_size %d, hdr_len %d\n",
1302                                        sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1303                                        tun16_to_cpu(tun, gso.hdr_len));
1304                                 print_hex_dump(KERN_ERR, "tun: ",
1305                                                DUMP_PREFIX_NONE,
1306                                                16, 1, skb->head,
1307                                                min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1308                                 WARN_ON_ONCE(1);
1309                                 return -EINVAL;
1310                         }
1311                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1312                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1313                 } else
1314                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1315
1316                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1317                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1318                         gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) +
1319                                                       vlan_hlen);
1320                         gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset);
1321                 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1322                         gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1323                 } /* else everything is zero */
1324
1325                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1326                         return -EFAULT;
1327
1328                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1329         }
1330
1331         if (vlan_hlen) {
1332                 int ret;
1333                 struct {
1334                         __be16 h_vlan_proto;
1335                         __be16 h_vlan_TCI;
1336                 } veth;
1337
1338                 veth.h_vlan_proto = skb->vlan_proto;
1339                 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb));
1340
1341                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1342
1343                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1344                 if (ret || !iov_iter_count(iter))
1345                         goto done;
1346
1347                 ret = copy_to_iter(&veth, sizeof(veth), iter);
1348                 if (ret != sizeof(veth) || !iov_iter_count(iter))
1349                         goto done;
1350         }
1351
1352         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1353
1354 done:
1355         tun->dev->stats.tx_packets++;
1356         tun->dev->stats.tx_bytes += skb->len + vlan_hlen;
1357
1358         return total;
1359 }
1360
1361 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1362                            struct iov_iter *to,
1363                            int noblock)
1364 {
1365         struct sk_buff *skb;
1366         ssize_t ret;
1367         int peeked, err, off = 0;
1368
1369         tun_debug(KERN_INFO, tun, "tun_do_read\n");
1370
1371         if (!iov_iter_count(to))
1372                 return 0;
1373
1374         if (tun->dev->reg_state != NETREG_REGISTERED)
1375                 return -EIO;
1376
1377         /* Read frames from queue */
1378         skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0,
1379                                   &peeked, &off, &err);
1380         if (!skb)
1381                 return 0;
1382
1383         ret = tun_put_user(tun, tfile, skb, to);
1384         if (unlikely(ret < 0))
1385                 kfree_skb(skb);
1386         else
1387                 consume_skb(skb);
1388
1389         return ret;
1390 }
1391
1392 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1393 {
1394         struct file *file = iocb->ki_filp;
1395         struct tun_file *tfile = file->private_data;
1396         struct tun_struct *tun = __tun_get(tfile);
1397         ssize_t len = iov_iter_count(to), ret;
1398
1399         if (!tun)
1400                 return -EBADFD;
1401         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
1402         ret = min_t(ssize_t, ret, len);
1403         if (ret > 0)
1404                 iocb->ki_pos = ret;
1405         tun_put(tun);
1406         return ret;
1407 }
1408
1409 static void tun_free_netdev(struct net_device *dev)
1410 {
1411         struct tun_struct *tun = netdev_priv(dev);
1412
1413         BUG_ON(!(list_empty(&tun->disabled)));
1414         tun_flow_uninit(tun);
1415         security_tun_dev_free_security(tun->security);
1416         free_netdev(dev);
1417 }
1418
1419 static void tun_setup(struct net_device *dev)
1420 {
1421         struct tun_struct *tun = netdev_priv(dev);
1422
1423         tun->owner = INVALID_UID;
1424         tun->group = INVALID_GID;
1425
1426         dev->ethtool_ops = &tun_ethtool_ops;
1427         dev->destructor = tun_free_netdev;
1428 }
1429
1430 /* Trivial set of netlink ops to allow deleting tun or tap
1431  * device with netlink.
1432  */
1433 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1434 {
1435         return -EINVAL;
1436 }
1437
1438 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1439         .kind           = DRV_NAME,
1440         .priv_size      = sizeof(struct tun_struct),
1441         .setup          = tun_setup,
1442         .validate       = tun_validate,
1443 };
1444
1445 static void tun_sock_write_space(struct sock *sk)
1446 {
1447         struct tun_file *tfile;
1448         wait_queue_head_t *wqueue;
1449
1450         if (!sock_writeable(sk))
1451                 return;
1452
1453         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1454                 return;
1455
1456         wqueue = sk_sleep(sk);
1457         if (wqueue && waitqueue_active(wqueue))
1458                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1459                                                 POLLWRNORM | POLLWRBAND);
1460
1461         tfile = container_of(sk, struct tun_file, sk);
1462         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1463 }
1464
1465 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1466                        struct msghdr *m, size_t total_len)
1467 {
1468         int ret;
1469         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1470         struct tun_struct *tun = __tun_get(tfile);
1471
1472         if (!tun)
1473                 return -EBADFD;
1474
1475         ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1476                            m->msg_flags & MSG_DONTWAIT);
1477         tun_put(tun);
1478         return ret;
1479 }
1480
1481 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1482                        struct msghdr *m, size_t total_len,
1483                        int flags)
1484 {
1485         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1486         struct tun_struct *tun = __tun_get(tfile);
1487         int ret;
1488
1489         if (!tun)
1490                 return -EBADFD;
1491
1492         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1493                 ret = -EINVAL;
1494                 goto out;
1495         }
1496         if (flags & MSG_ERRQUEUE) {
1497                 ret = sock_recv_errqueue(sock->sk, m, total_len,
1498                                          SOL_PACKET, TUN_TX_TIMESTAMP);
1499                 goto out;
1500         }
1501         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1502         if (ret > total_len) {
1503                 m->msg_flags |= MSG_TRUNC;
1504                 ret = flags & MSG_TRUNC ? ret : total_len;
1505         }
1506 out:
1507         tun_put(tun);
1508         return ret;
1509 }
1510
1511 static int tun_release(struct socket *sock)
1512 {
1513         if (sock->sk)
1514                 sock_put(sock->sk);
1515         return 0;
1516 }
1517
1518 /* Ops structure to mimic raw sockets with tun */
1519 static const struct proto_ops tun_socket_ops = {
1520         .sendmsg = tun_sendmsg,
1521         .recvmsg = tun_recvmsg,
1522         .release = tun_release,
1523 };
1524
1525 static struct proto tun_proto = {
1526         .name           = "tun",
1527         .owner          = THIS_MODULE,
1528         .obj_size       = sizeof(struct tun_file),
1529 };
1530
1531 static int tun_flags(struct tun_struct *tun)
1532 {
1533         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1534 }
1535
1536 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1537                               char *buf)
1538 {
1539         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1540         return sprintf(buf, "0x%x\n", tun_flags(tun));
1541 }
1542
1543 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1544                               char *buf)
1545 {
1546         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1547         return uid_valid(tun->owner)?
1548                 sprintf(buf, "%u\n",
1549                         from_kuid_munged(current_user_ns(), tun->owner)):
1550                 sprintf(buf, "-1\n");
1551 }
1552
1553 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1554                               char *buf)
1555 {
1556         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1557         return gid_valid(tun->group) ?
1558                 sprintf(buf, "%u\n",
1559                         from_kgid_munged(current_user_ns(), tun->group)):
1560                 sprintf(buf, "-1\n");
1561 }
1562
1563 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1564 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1565 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1566
1567 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1568 {
1569         struct tun_struct *tun;
1570         struct tun_file *tfile = file->private_data;
1571         struct net_device *dev;
1572         int err;
1573
1574         if (tfile->detached)
1575                 return -EINVAL;
1576
1577         dev = __dev_get_by_name(net, ifr->ifr_name);
1578         if (dev) {
1579                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1580                         return -EBUSY;
1581                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1582                         tun = netdev_priv(dev);
1583                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1584                         tun = netdev_priv(dev);
1585                 else
1586                         return -EINVAL;
1587
1588                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1589                     !!(tun->flags & IFF_MULTI_QUEUE))
1590                         return -EINVAL;
1591
1592                 if (tun_not_capable(tun))
1593                         return -EPERM;
1594                 err = security_tun_dev_open(tun->security);
1595                 if (err < 0)
1596                         return err;
1597
1598                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1599                 if (err < 0)
1600                         return err;
1601
1602                 if (tun->flags & IFF_MULTI_QUEUE &&
1603                     (tun->numqueues + tun->numdisabled > 1)) {
1604                         /* One or more queue has already been attached, no need
1605                          * to initialize the device again.
1606                          */
1607                         return 0;
1608                 }
1609         }
1610         else {
1611                 char *name;
1612                 unsigned long flags = 0;
1613                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1614                              MAX_TAP_QUEUES : 1;
1615
1616                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1617                         return -EPERM;
1618                 err = security_tun_dev_create();
1619                 if (err < 0)
1620                         return err;
1621
1622                 /* Set dev type */
1623                 if (ifr->ifr_flags & IFF_TUN) {
1624                         /* TUN device */
1625                         flags |= IFF_TUN;
1626                         name = "tun%d";
1627                 } else if (ifr->ifr_flags & IFF_TAP) {
1628                         /* TAP device */
1629                         flags |= IFF_TAP;
1630                         name = "tap%d";
1631                 } else
1632                         return -EINVAL;
1633
1634                 if (*ifr->ifr_name)
1635                         name = ifr->ifr_name;
1636
1637                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1638                                        NET_NAME_UNKNOWN, tun_setup, queues,
1639                                        queues);
1640
1641                 if (!dev)
1642                         return -ENOMEM;
1643
1644                 dev_net_set(dev, net);
1645                 dev->rtnl_link_ops = &tun_link_ops;
1646                 dev->ifindex = tfile->ifindex;
1647
1648                 tun = netdev_priv(dev);
1649                 tun->dev = dev;
1650                 tun->flags = flags;
1651                 tun->txflt.count = 0;
1652                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1653
1654                 tun->filter_attached = false;
1655                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1656
1657                 spin_lock_init(&tun->lock);
1658
1659                 err = security_tun_dev_alloc_security(&tun->security);
1660                 if (err < 0)
1661                         goto err_free_dev;
1662
1663                 tun_net_init(dev);
1664                 tun_flow_init(tun);
1665
1666                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1667                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1668                                    NETIF_F_HW_VLAN_STAG_TX;
1669                 dev->features = dev->hw_features;
1670                 dev->vlan_features = dev->features &
1671                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
1672                                        NETIF_F_HW_VLAN_STAG_TX);
1673
1674                 INIT_LIST_HEAD(&tun->disabled);
1675                 err = tun_attach(tun, file, false);
1676                 if (err < 0)
1677                         goto err_free_flow;
1678
1679                 err = register_netdevice(tun->dev);
1680                 if (err < 0)
1681                         goto err_detach;
1682
1683                 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1684                     device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1685                     device_create_file(&tun->dev->dev, &dev_attr_group))
1686                         pr_err("Failed to create tun sysfs files\n");
1687         }
1688
1689         netif_carrier_on(tun->dev);
1690
1691         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1692
1693         tun->flags = (tun->flags & ~TUN_FEATURES) |
1694                 (ifr->ifr_flags & TUN_FEATURES);
1695
1696         /* Make sure persistent devices do not get stuck in
1697          * xoff state.
1698          */
1699         if (netif_running(tun->dev))
1700                 netif_tx_wake_all_queues(tun->dev);
1701
1702         strcpy(ifr->ifr_name, tun->dev->name);
1703         return 0;
1704
1705 err_detach:
1706         tun_detach_all(dev);
1707 err_free_flow:
1708         tun_flow_uninit(tun);
1709         security_tun_dev_free_security(tun->security);
1710 err_free_dev:
1711         free_netdev(dev);
1712         return err;
1713 }
1714
1715 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1716                        struct ifreq *ifr)
1717 {
1718         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1719
1720         strcpy(ifr->ifr_name, tun->dev->name);
1721
1722         ifr->ifr_flags = tun_flags(tun);
1723
1724 }
1725
1726 /* This is like a cut-down ethtool ops, except done via tun fd so no
1727  * privs required. */
1728 static int set_offload(struct tun_struct *tun, unsigned long arg)
1729 {
1730         netdev_features_t features = 0;
1731
1732         if (arg & TUN_F_CSUM) {
1733                 features |= NETIF_F_HW_CSUM;
1734                 arg &= ~TUN_F_CSUM;
1735
1736                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1737                         if (arg & TUN_F_TSO_ECN) {
1738                                 features |= NETIF_F_TSO_ECN;
1739                                 arg &= ~TUN_F_TSO_ECN;
1740                         }
1741                         if (arg & TUN_F_TSO4)
1742                                 features |= NETIF_F_TSO;
1743                         if (arg & TUN_F_TSO6)
1744                                 features |= NETIF_F_TSO6;
1745                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1746                 }
1747         }
1748
1749         /* This gives the user a way to test for new features in future by
1750          * trying to set them. */
1751         if (arg)
1752                 return -EINVAL;
1753
1754         tun->set_features = features;
1755         netdev_update_features(tun->dev);
1756
1757         return 0;
1758 }
1759
1760 static void tun_detach_filter(struct tun_struct *tun, int n)
1761 {
1762         int i;
1763         struct tun_file *tfile;
1764
1765         for (i = 0; i < n; i++) {
1766                 tfile = rtnl_dereference(tun->tfiles[i]);
1767                 sk_detach_filter(tfile->socket.sk);
1768         }
1769
1770         tun->filter_attached = false;
1771 }
1772
1773 static int tun_attach_filter(struct tun_struct *tun)
1774 {
1775         int i, ret = 0;
1776         struct tun_file *tfile;
1777
1778         for (i = 0; i < tun->numqueues; i++) {
1779                 tfile = rtnl_dereference(tun->tfiles[i]);
1780                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1781                 if (ret) {
1782                         tun_detach_filter(tun, i);
1783                         return ret;
1784                 }
1785         }
1786
1787         tun->filter_attached = true;
1788         return ret;
1789 }
1790
1791 static void tun_set_sndbuf(struct tun_struct *tun)
1792 {
1793         struct tun_file *tfile;
1794         int i;
1795
1796         for (i = 0; i < tun->numqueues; i++) {
1797                 tfile = rtnl_dereference(tun->tfiles[i]);
1798                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1799         }
1800 }
1801
1802 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1803 {
1804         struct tun_file *tfile = file->private_data;
1805         struct tun_struct *tun;
1806         int ret = 0;
1807
1808         rtnl_lock();
1809
1810         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1811                 tun = tfile->detached;
1812                 if (!tun) {
1813                         ret = -EINVAL;
1814                         goto unlock;
1815                 }
1816                 ret = security_tun_dev_attach_queue(tun->security);
1817                 if (ret < 0)
1818                         goto unlock;
1819                 ret = tun_attach(tun, file, false);
1820         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1821                 tun = rtnl_dereference(tfile->tun);
1822                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1823                         ret = -EINVAL;
1824                 else
1825                         __tun_detach(tfile, false);
1826         } else
1827                 ret = -EINVAL;
1828
1829 unlock:
1830         rtnl_unlock();
1831         return ret;
1832 }
1833
1834 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1835                             unsigned long arg, int ifreq_len)
1836 {
1837         struct tun_file *tfile = file->private_data;
1838         struct tun_struct *tun;
1839         void __user* argp = (void __user*)arg;
1840         struct ifreq ifr;
1841         kuid_t owner;
1842         kgid_t group;
1843         int sndbuf;
1844         int vnet_hdr_sz;
1845         unsigned int ifindex;
1846         int ret;
1847
1848         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1849                 if (copy_from_user(&ifr, argp, ifreq_len))
1850                         return -EFAULT;
1851         } else {
1852                 memset(&ifr, 0, sizeof(ifr));
1853         }
1854         if (cmd == TUNGETFEATURES) {
1855                 /* Currently this just means: "what IFF flags are valid?".
1856                  * This is needed because we never checked for invalid flags on
1857                  * TUNSETIFF.
1858                  */
1859                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
1860                                 (unsigned int __user*)argp);
1861         } else if (cmd == TUNSETQUEUE)
1862                 return tun_set_queue(file, &ifr);
1863
1864         ret = 0;
1865         rtnl_lock();
1866
1867         tun = __tun_get(tfile);
1868         if (cmd == TUNSETIFF && !tun) {
1869                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1870
1871                 ret = tun_set_iff(tfile->net, file, &ifr);
1872
1873                 if (ret)
1874                         goto unlock;
1875
1876                 if (copy_to_user(argp, &ifr, ifreq_len))
1877                         ret = -EFAULT;
1878                 goto unlock;
1879         }
1880         if (cmd == TUNSETIFINDEX) {
1881                 ret = -EPERM;
1882                 if (tun)
1883                         goto unlock;
1884
1885                 ret = -EFAULT;
1886                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
1887                         goto unlock;
1888
1889                 ret = 0;
1890                 tfile->ifindex = ifindex;
1891                 goto unlock;
1892         }
1893
1894         ret = -EBADFD;
1895         if (!tun)
1896                 goto unlock;
1897
1898         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1899
1900         ret = 0;
1901         switch (cmd) {
1902         case TUNGETIFF:
1903                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1904
1905                 if (tfile->detached)
1906                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
1907                 if (!tfile->socket.sk->sk_filter)
1908                         ifr.ifr_flags |= IFF_NOFILTER;
1909
1910                 if (copy_to_user(argp, &ifr, ifreq_len))
1911                         ret = -EFAULT;
1912                 break;
1913
1914         case TUNSETNOCSUM:
1915                 /* Disable/Enable checksum */
1916
1917                 /* [unimplemented] */
1918                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1919                           arg ? "disabled" : "enabled");
1920                 break;
1921
1922         case TUNSETPERSIST:
1923                 /* Disable/Enable persist mode. Keep an extra reference to the
1924                  * module to prevent the module being unprobed.
1925                  */
1926                 if (arg && !(tun->flags & IFF_PERSIST)) {
1927                         tun->flags |= IFF_PERSIST;
1928                         __module_get(THIS_MODULE);
1929                 }
1930                 if (!arg && (tun->flags & IFF_PERSIST)) {
1931                         tun->flags &= ~IFF_PERSIST;
1932                         module_put(THIS_MODULE);
1933                 }
1934
1935                 tun_debug(KERN_INFO, tun, "persist %s\n",
1936                           arg ? "enabled" : "disabled");
1937                 break;
1938
1939         case TUNSETOWNER:
1940                 /* Set owner of the device */
1941                 owner = make_kuid(current_user_ns(), arg);
1942                 if (!uid_valid(owner)) {
1943                         ret = -EINVAL;
1944                         break;
1945                 }
1946                 tun->owner = owner;
1947                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
1948                           from_kuid(&init_user_ns, tun->owner));
1949                 break;
1950
1951         case TUNSETGROUP:
1952                 /* Set group of the device */
1953                 group = make_kgid(current_user_ns(), arg);
1954                 if (!gid_valid(group)) {
1955                         ret = -EINVAL;
1956                         break;
1957                 }
1958                 tun->group = group;
1959                 tun_debug(KERN_INFO, tun, "group set to %u\n",
1960                           from_kgid(&init_user_ns, tun->group));
1961                 break;
1962
1963         case TUNSETLINK:
1964                 /* Only allow setting the type when the interface is down */
1965                 if (tun->dev->flags & IFF_UP) {
1966                         tun_debug(KERN_INFO, tun,
1967                                   "Linktype set failed because interface is up\n");
1968                         ret = -EBUSY;
1969                 } else {
1970                         tun->dev->type = (int) arg;
1971                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1972                                   tun->dev->type);
1973                         ret = 0;
1974                 }
1975                 break;
1976
1977 #ifdef TUN_DEBUG
1978         case TUNSETDEBUG:
1979                 tun->debug = arg;
1980                 break;
1981 #endif
1982         case TUNSETOFFLOAD:
1983                 ret = set_offload(tun, arg);
1984                 break;
1985
1986         case TUNSETTXFILTER:
1987                 /* Can be set only for TAPs */
1988                 ret = -EINVAL;
1989                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1990                         break;
1991                 ret = update_filter(&tun->txflt, (void __user *)arg);
1992                 break;
1993
1994         case SIOCGIFHWADDR:
1995                 /* Get hw address */
1996                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1997                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1998                 if (copy_to_user(argp, &ifr, ifreq_len))
1999                         ret = -EFAULT;
2000                 break;
2001
2002         case SIOCSIFHWADDR:
2003                 /* Set hw address */
2004                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2005                           ifr.ifr_hwaddr.sa_data);
2006
2007                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2008                 break;
2009
2010         case TUNGETSNDBUF:
2011                 sndbuf = tfile->socket.sk->sk_sndbuf;
2012                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2013                         ret = -EFAULT;
2014                 break;
2015
2016         case TUNSETSNDBUF:
2017                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2018                         ret = -EFAULT;
2019                         break;
2020                 }
2021
2022                 tun->sndbuf = sndbuf;
2023                 tun_set_sndbuf(tun);
2024                 break;
2025
2026         case TUNGETVNETHDRSZ:
2027                 vnet_hdr_sz = tun->vnet_hdr_sz;
2028                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2029                         ret = -EFAULT;
2030                 break;
2031
2032         case TUNSETVNETHDRSZ:
2033                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2034                         ret = -EFAULT;
2035                         break;
2036                 }
2037                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2038                         ret = -EINVAL;
2039                         break;
2040                 }
2041
2042                 tun->vnet_hdr_sz = vnet_hdr_sz;
2043                 break;
2044
2045         case TUNATTACHFILTER:
2046                 /* Can be set only for TAPs */
2047                 ret = -EINVAL;
2048                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2049                         break;
2050                 ret = -EFAULT;
2051                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2052                         break;
2053
2054                 ret = tun_attach_filter(tun);
2055                 break;
2056
2057         case TUNDETACHFILTER:
2058                 /* Can be set only for TAPs */
2059                 ret = -EINVAL;
2060                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2061                         break;
2062                 ret = 0;
2063                 tun_detach_filter(tun, tun->numqueues);
2064                 break;
2065
2066         case TUNGETFILTER:
2067                 ret = -EINVAL;
2068                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2069                         break;
2070                 ret = -EFAULT;
2071                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2072                         break;
2073                 ret = 0;
2074                 break;
2075
2076         default:
2077                 ret = -EINVAL;
2078                 break;
2079         }
2080
2081 unlock:
2082         rtnl_unlock();
2083         if (tun)
2084                 tun_put(tun);
2085         return ret;
2086 }
2087
2088 static long tun_chr_ioctl(struct file *file,
2089                           unsigned int cmd, unsigned long arg)
2090 {
2091         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2092 }
2093
2094 #ifdef CONFIG_COMPAT
2095 static long tun_chr_compat_ioctl(struct file *file,
2096                          unsigned int cmd, unsigned long arg)
2097 {
2098         switch (cmd) {
2099         case TUNSETIFF:
2100         case TUNGETIFF:
2101         case TUNSETTXFILTER:
2102         case TUNGETSNDBUF:
2103         case TUNSETSNDBUF:
2104         case SIOCGIFHWADDR:
2105         case SIOCSIFHWADDR:
2106                 arg = (unsigned long)compat_ptr(arg);
2107                 break;
2108         default:
2109                 arg = (compat_ulong_t)arg;
2110                 break;
2111         }
2112
2113         /*
2114          * compat_ifreq is shorter than ifreq, so we must not access beyond
2115          * the end of that structure. All fields that are used in this
2116          * driver are compatible though, we don't need to convert the
2117          * contents.
2118          */
2119         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2120 }
2121 #endif /* CONFIG_COMPAT */
2122
2123 static int tun_chr_fasync(int fd, struct file *file, int on)
2124 {
2125         struct tun_file *tfile = file->private_data;
2126         int ret;
2127
2128         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2129                 goto out;
2130
2131         if (on) {
2132                 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2133                 tfile->flags |= TUN_FASYNC;
2134         } else
2135                 tfile->flags &= ~TUN_FASYNC;
2136         ret = 0;
2137 out:
2138         return ret;
2139 }
2140
2141 static int tun_chr_open(struct inode *inode, struct file * file)
2142 {
2143         struct tun_file *tfile;
2144
2145         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2146
2147         tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
2148                                             &tun_proto);
2149         if (!tfile)
2150                 return -ENOMEM;
2151         RCU_INIT_POINTER(tfile->tun, NULL);
2152         tfile->net = get_net(current->nsproxy->net_ns);
2153         tfile->flags = 0;
2154         tfile->ifindex = 0;
2155
2156         init_waitqueue_head(&tfile->wq.wait);
2157         RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2158
2159         tfile->socket.file = file;
2160         tfile->socket.ops = &tun_socket_ops;
2161
2162         sock_init_data(&tfile->socket, &tfile->sk);
2163         sk_change_net(&tfile->sk, tfile->net);
2164
2165         tfile->sk.sk_write_space = tun_sock_write_space;
2166         tfile->sk.sk_sndbuf = INT_MAX;
2167
2168         file->private_data = tfile;
2169         set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
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         struct net *net = tfile->net;
2181
2182         tun_detach(tfile, true);
2183         put_net(net);
2184
2185         return 0;
2186 }
2187
2188 #ifdef CONFIG_PROC_FS
2189 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2190 {
2191         struct tun_struct *tun;
2192         struct ifreq ifr;
2193
2194         memset(&ifr, 0, sizeof(ifr));
2195
2196         rtnl_lock();
2197         tun = tun_get(f);
2198         if (tun)
2199                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2200         rtnl_unlock();
2201
2202         if (tun)
2203                 tun_put(tun);
2204
2205         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2206 }
2207 #endif
2208
2209 static const struct file_operations tun_fops = {
2210         .owner  = THIS_MODULE,
2211         .llseek = no_llseek,
2212         .read  = new_sync_read,
2213         .write = new_sync_write,
2214         .read_iter  = tun_chr_read_iter,
2215         .write_iter = tun_chr_write_iter,
2216         .poll   = tun_chr_poll,
2217         .unlocked_ioctl = tun_chr_ioctl,
2218 #ifdef CONFIG_COMPAT
2219         .compat_ioctl = tun_chr_compat_ioctl,
2220 #endif
2221         .open   = tun_chr_open,
2222         .release = tun_chr_close,
2223         .fasync = tun_chr_fasync,
2224 #ifdef CONFIG_PROC_FS
2225         .show_fdinfo = tun_chr_show_fdinfo,
2226 #endif
2227 };
2228
2229 static struct miscdevice tun_miscdev = {
2230         .minor = TUN_MINOR,
2231         .name = "tun",
2232         .nodename = "net/tun",
2233         .fops = &tun_fops,
2234 };
2235
2236 /* ethtool interface */
2237
2238 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2239 {
2240         cmd->supported          = 0;
2241         cmd->advertising        = 0;
2242         ethtool_cmd_speed_set(cmd, SPEED_10);
2243         cmd->duplex             = DUPLEX_FULL;
2244         cmd->port               = PORT_TP;
2245         cmd->phy_address        = 0;
2246         cmd->transceiver        = XCVR_INTERNAL;
2247         cmd->autoneg            = AUTONEG_DISABLE;
2248         cmd->maxtxpkt           = 0;
2249         cmd->maxrxpkt           = 0;
2250         return 0;
2251 }
2252
2253 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2254 {
2255         struct tun_struct *tun = netdev_priv(dev);
2256
2257         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2258         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2259
2260         switch (tun->flags & TUN_TYPE_MASK) {
2261         case IFF_TUN:
2262                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2263                 break;
2264         case IFF_TAP:
2265                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2266                 break;
2267         }
2268 }
2269
2270 static u32 tun_get_msglevel(struct net_device *dev)
2271 {
2272 #ifdef TUN_DEBUG
2273         struct tun_struct *tun = netdev_priv(dev);
2274         return tun->debug;
2275 #else
2276         return -EOPNOTSUPP;
2277 #endif
2278 }
2279
2280 static void tun_set_msglevel(struct net_device *dev, u32 value)
2281 {
2282 #ifdef TUN_DEBUG
2283         struct tun_struct *tun = netdev_priv(dev);
2284         tun->debug = value;
2285 #endif
2286 }
2287
2288 static const struct ethtool_ops tun_ethtool_ops = {
2289         .get_settings   = tun_get_settings,
2290         .get_drvinfo    = tun_get_drvinfo,
2291         .get_msglevel   = tun_get_msglevel,
2292         .set_msglevel   = tun_set_msglevel,
2293         .get_link       = ethtool_op_get_link,
2294         .get_ts_info    = ethtool_op_get_ts_info,
2295 };
2296
2297
2298 static int __init tun_init(void)
2299 {
2300         int ret = 0;
2301
2302         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2303         pr_info("%s\n", DRV_COPYRIGHT);
2304
2305         ret = rtnl_link_register(&tun_link_ops);
2306         if (ret) {
2307                 pr_err("Can't register link_ops\n");
2308                 goto err_linkops;
2309         }
2310
2311         ret = misc_register(&tun_miscdev);
2312         if (ret) {
2313                 pr_err("Can't register misc device %d\n", TUN_MINOR);
2314                 goto err_misc;
2315         }
2316         return  0;
2317 err_misc:
2318         rtnl_link_unregister(&tun_link_ops);
2319 err_linkops:
2320         return ret;
2321 }
2322
2323 static void tun_cleanup(void)
2324 {
2325         misc_deregister(&tun_miscdev);
2326         rtnl_link_unregister(&tun_link_ops);
2327 }
2328
2329 /* Get an underlying socket object from tun file.  Returns error unless file is
2330  * attached to a device.  The returned object works like a packet socket, it
2331  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2332  * holding a reference to the file for as long as the socket is in use. */
2333 struct socket *tun_get_socket(struct file *file)
2334 {
2335         struct tun_file *tfile;
2336         if (file->f_op != &tun_fops)
2337                 return ERR_PTR(-EINVAL);
2338         tfile = file->private_data;
2339         if (!tfile)
2340                 return ERR_PTR(-EBADFD);
2341         return &tfile->socket;
2342 }
2343 EXPORT_SYMBOL_GPL(tun_get_socket);
2344
2345 module_init(tun_init);
2346 module_exit(tun_cleanup);
2347 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2348 MODULE_AUTHOR(DRV_COPYRIGHT);
2349 MODULE_LICENSE("GPL");
2350 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2351 MODULE_ALIAS("devname:net/tun");