Pileus Git - ~andy/linux/blob - 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/crc32.h>
  64 #include <linux/nsproxy.h>
  65 #include <linux/virtio_net.h>
  66 #include <linux/rcupdate.h>
  67 #include <net/net_namespace.h>
  68 #include <net/netns/generic.h>
  69 #include <net/rtnetlink.h>
  70 #include <net/sock.h>
  71
  72 #include <asm/uaccess.h>
  73
  74 /* Uncomment to enable debugging */
  75 /* #define TUN_DEBUG 1 */
  76
  77 #ifdef TUN_DEBUG
  78 static int debug;
  79
  80 #define tun_debug(level, tun, fmt, args...)                     \
  81 do {                                                            \
  82         if (tun->debug)                                         \
  83                 netdev_printk(level, tun->dev, fmt, ##args);    \
  84 } while (0)
  85 #define DBG1(level, fmt, args...)                               \
  86 do {                                                            \
  87         if (debug == 2)                                         \
  88                 printk(level fmt, ##args);                      \
  89 } while (0)
  90 #else
  91 #define tun_debug(level, tun, fmt, args...)                     \
  92 do {                                                            \
  93         if (0)                                                  \
  94                 netdev_printk(level, tun->dev, fmt, ##args);    \
  95 } while (0)
  96 #define DBG1(level, fmt, args...)                               \
  97 do {                                                            \
  98         if (0)                                                  \
  99                 printk(level fmt, ##args);                      \
 100 } while (0)
 101 #endif
 102
 103 #define GOODCOPY_LEN 128
 104
 105 #define FLT_EXACT_COUNT 8
 106 struct tap_filter {
 107         unsigned int    count;    /* Number of addrs. Zero means disabled */
 108         u32             mask[2];  /* Mask of the hashed addrs */
 109         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 110 };
 111
 112 /* 1024 is probably a high enough limit: modern hypervisors seem to support on
 113  * the order of 100-200 CPUs so this leaves us some breathing space if we want
 114  * to match a queue per guest CPU.
 115  */
 116 #define MAX_TAP_QUEUES 1024
 117
 118 #define TUN_FLOW_EXPIRE (3 * HZ)
 119
 120 /* A tun_file connects an open character device to a tuntap netdevice. It
 121  * also contains all socket related strctures (except sock_fprog and tap_filter)
 122  * to serve as one transmit queue for tuntap device. The sock_fprog and
 123  * tap_filter were kept in tun_struct since they were used for filtering for the
 124  * netdevice not for a specific queue (at least I didn't see the requirement for
 125  * this).
 126  *
 127  * RCU usage:
 128  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
 129  * other can only be read while rcu_read_lock or rtnl_lock is held.
 130  */
 131 struct tun_file {
 132         struct sock sk;
 133         struct socket socket;
 134         struct socket_wq wq;
 135         struct tun_struct __rcu *tun;
 136         struct net *net;
 137         struct fasync_struct *fasync;
 138         /* only used for fasnyc */
 139         unsigned int flags;
 140         u16 queue_index;
 141         struct list_head next;
 142         struct tun_struct *detached;
 143 };
 144
 145 struct tun_flow_entry {
 146         struct hlist_node hash_link;
 147         struct rcu_head rcu;
 148         struct tun_struct *tun;
 149
 150         u32 rxhash;
 151         int queue_index;
 152         unsigned long updated;
 153 };
 154
 155 #define TUN_NUM_FLOW_ENTRIES 1024
 156
 157 /* Since the socket were moved to tun_file, to preserve the behavior of persist
 158  * device, socket filter, sndbuf and vnet header size were restore when the
 159  * file were attached to a persist device.
 160  */
 161 struct tun_struct {
 162         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
 163         unsigned int            numqueues;
 164         unsigned int            flags;
 165         kuid_t                  owner;
 166         kgid_t                  group;
 167
 168         struct net_device       *dev;
 169         netdev_features_t       set_features;
 170 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 171                           NETIF_F_TSO6|NETIF_F_UFO)
 172
 173         int                     vnet_hdr_sz;
 174         int                     sndbuf;
 175         struct tap_filter       txflt;
 176         struct sock_fprog       fprog;
 177         /* protected by rtnl lock */
 178         bool                    filter_attached;
 179 #ifdef TUN_DEBUG
 180         int debug;
 181 #endif
 182         spinlock_t lock;
 183         struct kmem_cache *flow_cache;
 184         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 185         struct timer_list flow_gc_timer;
 186         unsigned long ageing_time;
 187         unsigned int numdisabled;
 188         struct list_head disabled;
 189 };
 190
 191 static inline u32 tun_hashfn(u32 rxhash)
 192 {
 193         return rxhash & 0x3ff;
 194 }
 195
 196 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 197 {
 198         struct tun_flow_entry *e;
 199         struct hlist_node *n;
 200
 201         hlist_for_each_entry_rcu(e, n, head, hash_link) {
 202                 if (e->rxhash == rxhash)
 203                         return e;
 204         }
 205         return NULL;
 206 }
 207
 208 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 209                                               struct hlist_head *head,
 210                                               u32 rxhash, u16 queue_index)
 211 {
 212         struct tun_flow_entry *e = kmem_cache_alloc(tun->flow_cache,
 213                                                     GFP_ATOMIC);
 214         if (e) {
 215                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 216                           rxhash, queue_index);
 217                 e->updated = jiffies;
 218                 e->rxhash = rxhash;
 219                 e->queue_index = queue_index;
 220                 e->tun = tun;
 221                 hlist_add_head_rcu(&e->hash_link, head);
 222         }
 223         return e;
 224 }
 225
 226 static void tun_flow_free(struct rcu_head *head)
 227 {
 228         struct tun_flow_entry *e
 229                 = container_of(head, struct tun_flow_entry, rcu);
 230         kmem_cache_free(e->tun->flow_cache, e);
 231 }
 232
 233 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 234 {
 235         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 236                   e->rxhash, e->queue_index);
 237         hlist_del_rcu(&e->hash_link);
 238         call_rcu(&e->rcu, tun_flow_free);
 239 }
 240
 241 static void tun_flow_flush(struct tun_struct *tun)
 242 {
 243         int i;
 244
 245         spin_lock_bh(&tun->lock);
 246         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 247                 struct tun_flow_entry *e;
 248                 struct hlist_node *h, *n;
 249
 250                 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link)
 251                         tun_flow_delete(tun, e);
 252         }
 253         spin_unlock_bh(&tun->lock);
 254 }
 255
 256 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 257 {
 258         int i;
 259
 260         spin_lock_bh(&tun->lock);
 261         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 262                 struct tun_flow_entry *e;
 263                 struct hlist_node *h, *n;
 264
 265                 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link) {
 266                         if (e->queue_index == queue_index)
 267                                 tun_flow_delete(tun, e);
 268                 }
 269         }
 270         spin_unlock_bh(&tun->lock);
 271 }
 272
 273 static void tun_flow_cleanup(unsigned long data)
 274 {
 275         struct tun_struct *tun = (struct tun_struct *)data;
 276         unsigned long delay = tun->ageing_time;
 277         unsigned long next_timer = jiffies + delay;
 278         unsigned long count = 0;
 279         int i;
 280
 281         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 282
 283         spin_lock_bh(&tun->lock);
 284         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 285                 struct tun_flow_entry *e;
 286                 struct hlist_node *h, *n;
 287
 288                 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link) {
 289                         unsigned long this_timer;
 290                         count++;
 291                         this_timer = e->updated + delay;
 292                         if (time_before_eq(this_timer, jiffies))
 293                                 tun_flow_delete(tun, e);
 294                         else if (time_before(this_timer, next_timer))
 295                                 next_timer = this_timer;
 296                 }
 297         }
 298
 299         if (count)
 300                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 301         spin_unlock_bh(&tun->lock);
 302 }
 303
 304 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 305                             u16 queue_index)
 306 {
 307         struct hlist_head *head;
 308         struct tun_flow_entry *e;
 309         unsigned long delay = tun->ageing_time;
 310
 311         if (!rxhash)
 312                 return;
 313         else
 314                 head = &tun->flows[tun_hashfn(rxhash)];
 315
 316         rcu_read_lock();
 317
 318         if (tun->numqueues == 1)
 319                 goto unlock;
 320
 321         e = tun_flow_find(head, rxhash);
 322         if (likely(e)) {
 323                 /* TODO: keep queueing to old queue until it's empty? */
 324                 e->queue_index = queue_index;
 325                 e->updated = jiffies;
 326         } else {
 327                 spin_lock_bh(&tun->lock);
 328                 if (!tun_flow_find(head, rxhash))
 329                         tun_flow_create(tun, head, rxhash, queue_index);
 330
 331                 if (!timer_pending(&tun->flow_gc_timer))
 332                         mod_timer(&tun->flow_gc_timer,
 333                                   round_jiffies_up(jiffies + delay));
 334                 spin_unlock_bh(&tun->lock);
 335         }
 336
 337 unlock:
 338         rcu_read_unlock();
 339 }
 340
 341 /* We try to identify a flow through its rxhash first. The reason that
 342  * we do not check rxq no. is becuase some cards(e.g 82599), chooses
 343  * the rxq based on the txq where the last packet of the flow comes. As
 344  * the userspace application move between processors, we may get a
 345  * different rxq no. here. If we could not get rxhash, then we would
 346  * hope the rxq no. may help here.
 347  */
 348 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb)
 349 {
 350         struct tun_struct *tun = netdev_priv(dev);
 351         struct tun_flow_entry *e;
 352         u32 txq = 0;
 353         u32 numqueues = 0;
 354
 355         rcu_read_lock();
 356         numqueues = tun->numqueues;
 357
 358         txq = skb_get_rxhash(skb);
 359         if (txq) {
 360                 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 361                 if (e)
 362                         txq = e->queue_index;
 363                 else
 364                         /* use multiply and shift instead of expensive divide */
 365                         txq = ((u64)txq * numqueues) >> 32;
 366         } else if (likely(skb_rx_queue_recorded(skb))) {
 367                 txq = skb_get_rx_queue(skb);
 368                 while (unlikely(txq >= numqueues))
 369                         txq -= numqueues;
 370         }
 371
 372         rcu_read_unlock();
 373         return txq;
 374 }
 375
 376 static inline bool tun_not_capable(struct tun_struct *tun)
 377 {
 378         const struct cred *cred = current_cred();
 379         struct net *net = dev_net(tun->dev);
 380
 381         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 382                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 383                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 384 }
 385
 386 static void tun_set_real_num_queues(struct tun_struct *tun)
 387 {
 388         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 389         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 390 }
 391
 392 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 393 {
 394         tfile->detached = tun;
 395         list_add_tail(&tfile->next, &tun->disabled);
 396         ++tun->numdisabled;
 397 }
 398
 399 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 400 {
 401         struct tun_struct *tun = tfile->detached;
 402
 403         tfile->detached = NULL;
 404         list_del_init(&tfile->next);
 405         --tun->numdisabled;
 406         return tun;
 407 }
 408
 409 static void __tun_detach(struct tun_file *tfile, bool clean)
 410 {
 411         struct tun_file *ntfile;
 412         struct tun_struct *tun;
 413         struct net_device *dev;
 414
 415         tun = rcu_dereference_protected(tfile->tun,
 416                                         lockdep_rtnl_is_held());
 417         if (tun) {
 418                 u16 index = tfile->queue_index;
 419                 BUG_ON(index >= tun->numqueues);
 420                 dev = tun->dev;
 421
 422                 rcu_assign_pointer(tun->tfiles[index],
 423                                    tun->tfiles[tun->numqueues - 1]);
 424                 rcu_assign_pointer(tfile->tun, NULL);
 425                 ntfile = rcu_dereference_protected(tun->tfiles[index],
 426                                                    lockdep_rtnl_is_held());
 427                 ntfile->queue_index = index;
 428
 429                 --tun->numqueues;
 430                 if (clean)
 431                         sock_put(&tfile->sk);
 432                 else
 433                         tun_disable_queue(tun, tfile);
 434
 435                 synchronize_net();
 436                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 437                 /* Drop read queue */
 438                 skb_queue_purge(&tfile->sk.sk_receive_queue);
 439                 tun_set_real_num_queues(tun);
 440         } else if (tfile->detached && clean)
 441                 tun = tun_enable_queue(tfile);
 442
 443         if (clean) {
 444                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0 &&
 445                     !(tun->flags & TUN_PERSIST))
 446                         if (tun->dev->reg_state == NETREG_REGISTERED)
 447                                 unregister_netdevice(tun->dev);
 448
 449                 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
 450                                  &tfile->socket.flags));
 451                 sk_release_kernel(&tfile->sk);
 452         }
 453 }
 454
 455 static void tun_detach(struct tun_file *tfile, bool clean)
 456 {
 457         rtnl_lock();
 458         __tun_detach(tfile, clean);
 459         rtnl_unlock();
 460 }
 461
 462 static void tun_detach_all(struct net_device *dev)
 463 {
 464         struct tun_struct *tun = netdev_priv(dev);
 465         struct tun_file *tfile, *tmp;
 466         int i, n = tun->numqueues;
 467
 468         for (i = 0; i < n; i++) {
 469                 tfile = rcu_dereference_protected(tun->tfiles[i],
 470                                                   lockdep_rtnl_is_held());
 471                 BUG_ON(!tfile);
 472                 wake_up_all(&tfile->wq.wait);
 473                 rcu_assign_pointer(tfile->tun, NULL);
 474                 --tun->numqueues;
 475         }
 476         BUG_ON(tun->numqueues != 0);
 477
 478         synchronize_net();
 479         for (i = 0; i < n; i++) {
 480                 tfile = rcu_dereference_protected(tun->tfiles[i],
 481                                                   lockdep_rtnl_is_held());
 482                 /* Drop read queue */
 483                 skb_queue_purge(&tfile->sk.sk_receive_queue);
 484                 sock_put(&tfile->sk);
 485         }
 486         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 487                 tun_enable_queue(tfile);
 488                 skb_queue_purge(&tfile->sk.sk_receive_queue);
 489                 sock_put(&tfile->sk);
 490         }
 491         BUG_ON(tun->numdisabled != 0);
 492 }
 493
 494 static int tun_attach(struct tun_struct *tun, struct file *file)
 495 {
 496         struct tun_file *tfile = file->private_data;
 497         int err;
 498
 499         err = -EINVAL;
 500         if (rcu_dereference_protected(tfile->tun, lockdep_rtnl_is_held()))
 501                 goto out;
 502
 503         err = -EBUSY;
 504         if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1)
 505                 goto out;
 506
 507         err = -E2BIG;
 508         if (!tfile->detached &&
 509             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 510                 goto out;
 511
 512         err = 0;
 513
 514         /* Re-attach the filter to presist device */
 515         if (tun->filter_attached == true) {
 516                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 517                 if (!err)
 518                         goto out;
 519         }
 520         tfile->queue_index = tun->numqueues;
 521         rcu_assign_pointer(tfile->tun, tun);
 522         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 523         tun->numqueues++;
 524
 525         if (tfile->detached)
 526                 tun_enable_queue(tfile);
 527         else
 528                 sock_hold(&tfile->sk);
 529
 530         tun_set_real_num_queues(tun);
 531
 532         /* device is allowed to go away first, so no need to hold extra
 533          * refcnt.
 534          */
 535
 536 out:
 537         return err;
 538 }
 539
 540 static struct tun_struct *__tun_get(struct tun_file *tfile)
 541 {
 542         struct tun_struct *tun;
 543
 544         rcu_read_lock();
 545         tun = rcu_dereference(tfile->tun);
 546         if (tun)
 547                 dev_hold(tun->dev);
 548         rcu_read_unlock();
 549
 550         return tun;
 551 }
 552
 553 static struct tun_struct *tun_get(struct file *file)
 554 {
 555         return __tun_get(file->private_data);
 556 }
 557
 558 static void tun_put(struct tun_struct *tun)
 559 {
 560         dev_put(tun->dev);
 561 }
 562
 563 /* TAP filtering */
 564 static void addr_hash_set(u32 *mask, const u8 *addr)
 565 {
 566         int n = ether_crc(ETH_ALEN, addr) >> 26;
 567         mask[n >> 5] |= (1 << (n & 31));
 568 }
 569
 570 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 571 {
 572         int n = ether_crc(ETH_ALEN, addr) >> 26;
 573         return mask[n >> 5] & (1 << (n & 31));
 574 }
 575
 576 static int update_filter(struct tap_filter *filter, void __user *arg)
 577 {
 578         struct { u8 u[ETH_ALEN]; } *addr;
 579         struct tun_filter uf;
 580         int err, alen, n, nexact;
 581
 582         if (copy_from_user(&uf, arg, sizeof(uf)))
 583                 return -EFAULT;
 584
 585         if (!uf.count) {
 586                 /* Disabled */
 587                 filter->count = 0;
 588                 return 0;
 589         }
 590
 591         alen = ETH_ALEN * uf.count;
 592         addr = kmalloc(alen, GFP_KERNEL);
 593         if (!addr)
 594                 return -ENOMEM;
 595
 596         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 597                 err = -EFAULT;
 598                 goto done;
 599         }
 600
 601         /* The filter is updated without holding any locks. Which is
 602          * perfectly safe. We disable it first and in the worst
 603          * case we'll accept a few undesired packets. */
 604         filter->count = 0;
 605         wmb();
 606
 607         /* Use first set of addresses as an exact filter */
 608         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 609                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 610
 611         nexact = n;
 612
 613         /* Remaining multicast addresses are hashed,
 614          * unicast will leave the filter disabled. */
 615         memset(filter->mask, 0, sizeof(filter->mask));
 616         for (; n < uf.count; n++) {
 617                 if (!is_multicast_ether_addr(addr[n].u)) {
 618                         err = 0; /* no filter */
 619                         goto done;
 620                 }
 621                 addr_hash_set(filter->mask, addr[n].u);
 622         }
 623
 624         /* For ALLMULTI just set the mask to all ones.
 625          * This overrides the mask populated above. */
 626         if ((uf.flags & TUN_FLT_ALLMULTI))
 627                 memset(filter->mask, ~0, sizeof(filter->mask));
 628
 629         /* Now enable the filter */
 630         wmb();
 631         filter->count = nexact;
 632
 633         /* Return the number of exact filters */
 634         err = nexact;
 635
 636 done:
 637         kfree(addr);
 638         return err;
 639 }
 640
 641 /* Returns: 0 - drop, !=0 - accept */
 642 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 643 {
 644         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 645          * at this point. */
 646         struct ethhdr *eh = (struct ethhdr *) skb->data;
 647         int i;
 648
 649         /* Exact match */
 650         for (i = 0; i < filter->count; i++)
 651                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 652                         return 1;
 653
 654         /* Inexact match (multicast only) */
 655         if (is_multicast_ether_addr(eh->h_dest))
 656                 return addr_hash_test(filter->mask, eh->h_dest);
 657
 658         return 0;
 659 }
 660
 661 /*
 662  * Checks whether the packet is accepted or not.
 663  * Returns: 0 - drop, !=0 - accept
 664  */
 665 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 666 {
 667         if (!filter->count)
 668                 return 1;
 669
 670         return run_filter(filter, skb);
 671 }
 672
 673 /* Network device part of the driver */
 674
 675 static const struct ethtool_ops tun_ethtool_ops;
 676
 677 /* Net device detach from fd. */
 678 static void tun_net_uninit(struct net_device *dev)
 679 {
 680         tun_detach_all(dev);
 681 }
 682
 683 /* Net device open. */
 684 static int tun_net_open(struct net_device *dev)
 685 {
 686         netif_tx_start_all_queues(dev);
 687         return 0;
 688 }
 689
 690 /* Net device close. */
 691 static int tun_net_close(struct net_device *dev)
 692 {
 693         netif_tx_stop_all_queues(dev);
 694         return 0;
 695 }
 696
 697 /* Net device start xmit */
 698 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 699 {
 700         struct tun_struct *tun = netdev_priv(dev);
 701         int txq = skb->queue_mapping;
 702         struct tun_file *tfile;
 703
 704         rcu_read_lock();
 705         tfile = rcu_dereference(tun->tfiles[txq]);
 706
 707         /* Drop packet if interface is not attached */
 708         if (txq >= tun->numqueues)
 709                 goto drop;
 710
 711         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 712
 713         BUG_ON(!tfile);
 714
 715         /* Drop if the filter does not like it.
 716          * This is a noop if the filter is disabled.
 717          * Filter can be enabled only for the TAP devices. */
 718         if (!check_filter(&tun->txflt, skb))
 719                 goto drop;
 720
 721         if (tfile->socket.sk->sk_filter &&
 722             sk_filter(tfile->socket.sk, skb))
 723                 goto drop;
 724
 725         /* Limit the number of packets queued by dividing txq length with the
 726          * number of queues.
 727          */
 728         if (skb_queue_len(&tfile->socket.sk->sk_receive_queue)
 729                           >= dev->tx_queue_len / tun->numqueues)
 730                 goto drop;
 731
 732         /* Orphan the skb - required as we might hang on to it
 733          * for indefinite time. */
 734         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 735                 goto drop;
 736         skb_orphan(skb);
 737
 738         /* Enqueue packet */
 739         skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
 740
 741         /* Notify and wake up reader process */
 742         if (tfile->flags & TUN_FASYNC)
 743                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
 744         wake_up_interruptible_poll(&tfile->wq.wait, POLLIN |
 745                                    POLLRDNORM | POLLRDBAND);
 746
 747         rcu_read_unlock();
 748         return NETDEV_TX_OK;
 749
 750 drop:
 751         dev->stats.tx_dropped++;
 752         skb_tx_error(skb);
 753         kfree_skb(skb);
 754         rcu_read_unlock();
 755         return NETDEV_TX_OK;
 756 }
 757
 758 static void tun_net_mclist(struct net_device *dev)
 759 {
 760         /*
 761          * This callback is supposed to deal with mc filter in
 762          * _rx_ path and has nothing to do with the _tx_ path.
 763          * In rx path we always accept everything userspace gives us.
 764          */
 765 }
 766
 767 #define MIN_MTU 68
 768 #define MAX_MTU 65535
 769
 770 static int
 771 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 772 {
 773         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 774                 return -EINVAL;
 775         dev->mtu = new_mtu;
 776         return 0;
 777 }
 778
 779 static netdev_features_t tun_net_fix_features(struct net_device *dev,
 780         netdev_features_t features)
 781 {
 782         struct tun_struct *tun = netdev_priv(dev);
 783
 784         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 785 }
 786 #ifdef CONFIG_NET_POLL_CONTROLLER
 787 static void tun_poll_controller(struct net_device *dev)
 788 {
 789         /*
 790          * Tun only receives frames when:
 791          * 1) the char device endpoint gets data from user space
 792          * 2) the tun socket gets a sendmsg call from user space
 793          * Since both of those are syncronous operations, we are guaranteed
 794          * never to have pending data when we poll for it
 795          * so theres nothing to do here but return.
 796          * We need this though so netpoll recognizes us as an interface that
 797          * supports polling, which enables bridge devices in virt setups to
 798          * still use netconsole
 799          */
 800         return;
 801 }
 802 #endif
 803 static const struct net_device_ops tun_netdev_ops = {
 804         .ndo_uninit             = tun_net_uninit,
 805         .ndo_open               = tun_net_open,
 806         .ndo_stop               = tun_net_close,
 807         .ndo_start_xmit         = tun_net_xmit,
 808         .ndo_change_mtu         = tun_net_change_mtu,
 809         .ndo_fix_features       = tun_net_fix_features,
 810         .ndo_select_queue       = tun_select_queue,
 811 #ifdef CONFIG_NET_POLL_CONTROLLER
 812         .ndo_poll_controller    = tun_poll_controller,
 813 #endif
 814 };
 815
 816 static const struct net_device_ops tap_netdev_ops = {
 817         .ndo_uninit             = tun_net_uninit,
 818         .ndo_open               = tun_net_open,
 819         .ndo_stop               = tun_net_close,
 820         .ndo_start_xmit         = tun_net_xmit,
 821         .ndo_change_mtu         = tun_net_change_mtu,
 822         .ndo_fix_features       = tun_net_fix_features,
 823         .ndo_set_rx_mode        = tun_net_mclist,
 824         .ndo_set_mac_address    = eth_mac_addr,
 825         .ndo_validate_addr      = eth_validate_addr,
 826         .ndo_select_queue       = tun_select_queue,
 827 #ifdef CONFIG_NET_POLL_CONTROLLER
 828         .ndo_poll_controller    = tun_poll_controller,
 829 #endif
 830 };
 831
 832 static int tun_flow_init(struct tun_struct *tun)
 833 {
 834         int i;
 835
 836         tun->flow_cache = kmem_cache_create("tun_flow_cache",
 837                                             sizeof(struct tun_flow_entry), 0, 0,
 838                                             NULL);
 839         if (!tun->flow_cache)
 840                 return -ENOMEM;
 841
 842         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
 843                 INIT_HLIST_HEAD(&tun->flows[i]);
 844
 845         tun->ageing_time = TUN_FLOW_EXPIRE;
 846         setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
 847         mod_timer(&tun->flow_gc_timer,
 848                   round_jiffies_up(jiffies + tun->ageing_time));
 849
 850         return 0;
 851 }
 852
 853 static void tun_flow_uninit(struct tun_struct *tun)
 854 {
 855         del_timer_sync(&tun->flow_gc_timer);
 856         tun_flow_flush(tun);
 857
 858         /* Wait for completion of call_rcu()'s */
 859         rcu_barrier();
 860         kmem_cache_destroy(tun->flow_cache);
 861 }
 862
 863 /* Initialize net device. */
 864 static void tun_net_init(struct net_device *dev)
 865 {
 866         struct tun_struct *tun = netdev_priv(dev);
 867
 868         switch (tun->flags & TUN_TYPE_MASK) {
 869         case TUN_TUN_DEV:
 870                 dev->netdev_ops = &tun_netdev_ops;
 871
 872                 /* Point-to-Point TUN Device */
 873                 dev->hard_header_len = 0;
 874                 dev->addr_len = 0;
 875                 dev->mtu = 1500;
 876
 877                 /* Zero header length */
 878                 dev->type = ARPHRD_NONE;
 879                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 880                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 881                 break;
 882
 883         case TUN_TAP_DEV:
 884                 dev->netdev_ops = &tap_netdev_ops;
 885                 /* Ethernet TAP Device */
 886                 ether_setup(dev);
 887                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 888                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
 889
 890                 eth_hw_addr_random(dev);
 891
 892                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 893                 break;
 894         }
 895 }
 896
 897 /* Character device part */
 898
 899 /* Poll */
 900 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
 901 {
 902         struct tun_file *tfile = file->private_data;
 903         struct tun_struct *tun = __tun_get(tfile);
 904         struct sock *sk;
 905         unsigned int mask = 0;
 906
 907         if (!tun)
 908                 return POLLERR;
 909
 910         sk = tfile->socket.sk;
 911
 912         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
 913
 914         poll_wait(file, &tfile->wq.wait, wait);
 915
 916         if (!skb_queue_empty(&sk->sk_receive_queue))
 917                 mask |= POLLIN | POLLRDNORM;
 918
 919         if (sock_writeable(sk) ||
 920             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 921              sock_writeable(sk)))
 922                 mask |= POLLOUT | POLLWRNORM;
 923
 924         if (tun->dev->reg_state != NETREG_REGISTERED)
 925                 mask = POLLERR;
 926
 927         tun_put(tun);
 928         return mask;
 929 }
 930
 931 /* prepad is the amount to reserve at front.  len is length after that.
 932  * linear is a hint as to how much to copy (usually headers). */
 933 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
 934                                      size_t prepad, size_t len,
 935                                      size_t linear, int noblock)
 936 {
 937         struct sock *sk = tfile->socket.sk;
 938         struct sk_buff *skb;
 939         int err;
 940
 941         /* Under a page?  Don't bother with paged skb. */
 942         if (prepad + len < PAGE_SIZE || !linear)
 943                 linear = len;
 944
 945         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 946                                    &err);
 947         if (!skb)
 948                 return ERR_PTR(err);
 949
 950         skb_reserve(skb, prepad);
 951         skb_put(skb, linear);
 952         skb->data_len = len - linear;
 953         skb->len += len - linear;
 954
 955         return skb;
 956 }
 957
 958 /* set skb frags from iovec, this can move to core network code for reuse */
 959 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
 960                                   int offset, size_t count)
 961 {
 962         int len = iov_length(from, count) - offset;
 963         int copy = skb_headlen(skb);
 964         int size, offset1 = 0;
 965         int i = 0;
 966
 967         /* Skip over from offset */
 968         while (count && (offset >= from->iov_len)) {
 969                 offset -= from->iov_len;
 970                 ++from;
 971                 --count;
 972         }
 973
 974         /* copy up to skb headlen */
 975         while (count && (copy > 0)) {
 976                 size = min_t(unsigned int, copy, from->iov_len - offset);
 977                 if (copy_from_user(skb->data + offset1, from->iov_base + offset,
 978                                    size))
 979                         return -EFAULT;
 980                 if (copy > size) {
 981                         ++from;
 982                         --count;
 983                         offset = 0;
 984                 } else
 985                         offset += size;
 986                 copy -= size;
 987                 offset1 += size;
 988         }
 989
 990         if (len == offset1)
 991                 return 0;
 992
 993         while (count--) {
 994                 struct page *page[MAX_SKB_FRAGS];
 995                 int num_pages;
 996                 unsigned long base;
 997                 unsigned long truesize;
 998
 999                 len = from->iov_len - offset;
1000                 if (!len) {
1001                         offset = 0;
1002                         ++from;
1003                         continue;
1004                 }
1005                 base = (unsigned long)from->iov_base + offset;
1006                 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
1007                 if (i + size > MAX_SKB_FRAGS)
1008                         return -EMSGSIZE;
1009                 num_pages = get_user_pages_fast(base, size, 0, &page[i]);
1010                 if (num_pages != size) {
1011                         for (i = 0; i < num_pages; i++)
1012                                 put_page(page[i]);
1013                         return -EFAULT;
1014                 }
1015                 truesize = size * PAGE_SIZE;
1016                 skb->data_len += len;
1017                 skb->len += len;
1018                 skb->truesize += truesize;
1019                 atomic_add(truesize, &skb->sk->sk_wmem_alloc);
1020                 while (len) {
1021                         int off = base & ~PAGE_MASK;
1022                         int size = min_t(int, len, PAGE_SIZE - off);
1023                         __skb_fill_page_desc(skb, i, page[i], off, size);
1024                         skb_shinfo(skb)->nr_frags++;
1025                         /* increase sk_wmem_alloc */
1026                         base += size;
1027                         len -= size;
1028                         i++;
1029                 }
1030                 offset = 0;
1031                 ++from;
1032         }
1033         return 0;
1034 }
1035
1036 /* Get packet from user space buffer */
1037 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1038                             void *msg_control, const struct iovec *iv,
1039                             size_t total_len, size_t count, int noblock)
1040 {
1041         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1042         struct sk_buff *skb;
1043         size_t len = total_len, align = NET_SKB_PAD;
1044         struct virtio_net_hdr gso = { 0 };
1045         int offset = 0;
1046         int copylen;
1047         bool zerocopy = false;
1048         int err;
1049         u32 rxhash;
1050
1051         if (!(tun->flags & TUN_NO_PI)) {
1052                 if ((len -= sizeof(pi)) > total_len)
1053                         return -EINVAL;
1054
1055                 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
1056                         return -EFAULT;
1057                 offset += sizeof(pi);
1058         }
1059
1060         if (tun->flags & TUN_VNET_HDR) {
1061                 if ((len -= tun->vnet_hdr_sz) > total_len)
1062                         return -EINVAL;
1063
1064                 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
1065                         return -EFAULT;
1066
1067                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1068                     gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
1069                         gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
1070
1071                 if (gso.hdr_len > len)
1072                         return -EINVAL;
1073                 offset += tun->vnet_hdr_sz;
1074         }
1075
1076         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
1077                 align += NET_IP_ALIGN;
1078                 if (unlikely(len < ETH_HLEN ||
1079                              (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
1080                         return -EINVAL;
1081         }
1082
1083         if (msg_control)
1084                 zerocopy = true;
1085
1086         if (zerocopy) {
1087                 /* Userspace may produce vectors with count greater than
1088                  * MAX_SKB_FRAGS, so we need to linearize parts of the skb
1089                  * to let the rest of data to be fit in the frags.
1090                  */
1091                 if (count > MAX_SKB_FRAGS) {
1092                         copylen = iov_length(iv, count - MAX_SKB_FRAGS);
1093                         if (copylen < offset)
1094                                 copylen = 0;
1095                         else
1096                                 copylen -= offset;
1097                 } else
1098                                 copylen = 0;
1099                 /* There are 256 bytes to be copied in skb, so there is enough
1100                  * room for skb expand head in case it is used.
1101                  * The rest of the buffer is mapped from userspace.
1102                  */
1103                 if (copylen < gso.hdr_len)
1104                         copylen = gso.hdr_len;
1105                 if (!copylen)
1106                         copylen = GOODCOPY_LEN;
1107         } else
1108                 copylen = len;
1109
1110         skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, 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_iovec(skb, iv, offset, count);
1119         else
1120                 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
1121
1122         if (err) {
1123                 tun->dev->stats.rx_dropped++;
1124                 kfree_skb(skb);
1125                 return -EFAULT;
1126         }
1127
1128         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1129                 if (!skb_partial_csum_set(skb, gso.csum_start,
1130                                           gso.csum_offset)) {
1131                         tun->dev->stats.rx_frame_errors++;
1132                         kfree_skb(skb);
1133                         return -EINVAL;
1134                 }
1135         }
1136
1137         switch (tun->flags & TUN_TYPE_MASK) {
1138         case TUN_TUN_DEV:
1139                 if (tun->flags & TUN_NO_PI) {
1140                         switch (skb->data[0] & 0xf0) {
1141                         case 0x40:
1142                                 pi.proto = htons(ETH_P_IP);
1143                                 break;
1144                         case 0x60:
1145                                 pi.proto = htons(ETH_P_IPV6);
1146                                 break;
1147                         default:
1148                                 tun->dev->stats.rx_dropped++;
1149                                 kfree_skb(skb);
1150                                 return -EINVAL;
1151                         }
1152                 }
1153
1154                 skb_reset_mac_header(skb);
1155                 skb->protocol = pi.proto;
1156                 skb->dev = tun->dev;
1157                 break;
1158         case TUN_TAP_DEV:
1159                 skb->protocol = eth_type_trans(skb, tun->dev);
1160                 break;
1161         }
1162
1163         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1164                 pr_debug("GSO!\n");
1165                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1166                 case VIRTIO_NET_HDR_GSO_TCPV4:
1167                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1168                         break;
1169                 case VIRTIO_NET_HDR_GSO_TCPV6:
1170                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1171                         break;
1172                 case VIRTIO_NET_HDR_GSO_UDP:
1173                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1174                         break;
1175                 default:
1176                         tun->dev->stats.rx_frame_errors++;
1177                         kfree_skb(skb);
1178                         return -EINVAL;
1179                 }
1180
1181                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1182                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1183
1184                 skb_shinfo(skb)->gso_size = gso.gso_size;
1185                 if (skb_shinfo(skb)->gso_size == 0) {
1186                         tun->dev->stats.rx_frame_errors++;
1187                         kfree_skb(skb);
1188                         return -EINVAL;
1189                 }
1190
1191                 /* Header must be checked, and gso_segs computed. */
1192                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1193                 skb_shinfo(skb)->gso_segs = 0;
1194         }
1195
1196         /* copy skb_ubuf_info for callback when skb has no error */
1197         if (zerocopy) {
1198                 skb_shinfo(skb)->destructor_arg = msg_control;
1199                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1200         }
1201
1202         skb_reset_network_header(skb);
1203         rxhash = skb_get_rxhash(skb);
1204         netif_rx_ni(skb);
1205
1206         tun->dev->stats.rx_packets++;
1207         tun->dev->stats.rx_bytes += len;
1208
1209         tun_flow_update(tun, rxhash, tfile->queue_index);
1210         return total_len;
1211 }
1212
1213 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
1214                               unsigned long count, loff_t pos)
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         tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
1225
1226         result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count),
1227                               count, file->f_flags & O_NONBLOCK);
1228
1229         tun_put(tun);
1230         return result;
1231 }
1232
1233 /* Put packet to the user space buffer */
1234 static ssize_t tun_put_user(struct tun_struct *tun,
1235                             struct tun_file *tfile,
1236                             struct sk_buff *skb,
1237                             const struct iovec *iv, int len)
1238 {
1239         struct tun_pi pi = { 0, skb->protocol };
1240         ssize_t total = 0;
1241
1242         if (!(tun->flags & TUN_NO_PI)) {
1243                 if ((len -= sizeof(pi)) < 0)
1244                         return -EINVAL;
1245
1246                 if (len < skb->len) {
1247                         /* Packet will be striped */
1248                         pi.flags |= TUN_PKT_STRIP;
1249                 }
1250
1251                 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
1252                         return -EFAULT;
1253                 total += sizeof(pi);
1254         }
1255
1256         if (tun->flags & TUN_VNET_HDR) {
1257                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1258                 if ((len -= tun->vnet_hdr_sz) < 0)
1259                         return -EINVAL;
1260
1261                 if (skb_is_gso(skb)) {
1262                         struct skb_shared_info *sinfo = skb_shinfo(skb);
1263
1264                         /* This is a hint as to how much should be linear. */
1265                         gso.hdr_len = skb_headlen(skb);
1266                         gso.gso_size = sinfo->gso_size;
1267                         if (sinfo->gso_type & SKB_GSO_TCPV4)
1268                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1269                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
1270                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1271                         else if (sinfo->gso_type & SKB_GSO_UDP)
1272                                 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1273                         else {
1274                                 pr_err("unexpected GSO type: "
1275                                        "0x%x, gso_size %d, hdr_len %d\n",
1276                                        sinfo->gso_type, gso.gso_size,
1277                                        gso.hdr_len);
1278                                 print_hex_dump(KERN_ERR, "tun: ",
1279                                                DUMP_PREFIX_NONE,
1280                                                16, 1, skb->head,
1281                                                min((int)gso.hdr_len, 64), true);
1282                                 WARN_ON_ONCE(1);
1283                                 return -EINVAL;
1284                         }
1285                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1286                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1287                 } else
1288                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1289
1290                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1291                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1292                         gso.csum_start = skb_checksum_start_offset(skb);
1293                         gso.csum_offset = skb->csum_offset;
1294                 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1295                         gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1296                 } /* else everything is zero */
1297
1298                 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
1299                                                sizeof(gso))))
1300                         return -EFAULT;
1301                 total += tun->vnet_hdr_sz;
1302         }
1303
1304         len = min_t(int, skb->len, len);
1305
1306         skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
1307         total += skb->len;
1308
1309         tun->dev->stats.tx_packets++;
1310         tun->dev->stats.tx_bytes += len;
1311
1312         return total;
1313 }
1314
1315 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1316                            struct kiocb *iocb, const struct iovec *iv,
1317                            ssize_t len, int noblock)
1318 {
1319         DECLARE_WAITQUEUE(wait, current);
1320         struct sk_buff *skb;
1321         ssize_t ret = 0;
1322
1323         tun_debug(KERN_INFO, tun, "tun_do_read\n");
1324
1325         if (unlikely(!noblock))
1326                 add_wait_queue(&tfile->wq.wait, &wait);
1327         while (len) {
1328                 current->state = TASK_INTERRUPTIBLE;
1329
1330                 /* Read frames from the queue */
1331                 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) {
1332                         if (noblock) {
1333                                 ret = -EAGAIN;
1334                                 break;
1335                         }
1336                         if (signal_pending(current)) {
1337                                 ret = -ERESTARTSYS;
1338                                 break;
1339                         }
1340                         if (tun->dev->reg_state != NETREG_REGISTERED) {
1341                                 ret = -EIO;
1342                                 break;
1343                         }
1344
1345                         /* Nothing to read, let's sleep */
1346                         schedule();
1347                         continue;
1348                 }
1349
1350                 ret = tun_put_user(tun, tfile, skb, iv, len);
1351                 kfree_skb(skb);
1352                 break;
1353         }
1354
1355         current->state = TASK_RUNNING;
1356         if (unlikely(!noblock))
1357                 remove_wait_queue(&tfile->wq.wait, &wait);
1358
1359         return ret;
1360 }
1361
1362 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1363                             unsigned long count, loff_t pos)
1364 {
1365         struct file *file = iocb->ki_filp;
1366         struct tun_file *tfile = file->private_data;
1367         struct tun_struct *tun = __tun_get(tfile);
1368         ssize_t len, ret;
1369
1370         if (!tun)
1371                 return -EBADFD;
1372         len = iov_length(iv, count);
1373         if (len < 0) {
1374                 ret = -EINVAL;
1375                 goto out;
1376         }
1377
1378         ret = tun_do_read(tun, tfile, iocb, iv, len,
1379                           file->f_flags & O_NONBLOCK);
1380         ret = min_t(ssize_t, ret, len);
1381 out:
1382         tun_put(tun);
1383         return ret;
1384 }
1385
1386 static void tun_free_netdev(struct net_device *dev)
1387 {
1388         struct tun_struct *tun = netdev_priv(dev);
1389
1390         BUG_ON(!(list_empty(&tun->disabled)));
1391         tun_flow_uninit(tun);
1392         free_netdev(dev);
1393 }
1394
1395 static void tun_setup(struct net_device *dev)
1396 {
1397         struct tun_struct *tun = netdev_priv(dev);
1398
1399         tun->owner = INVALID_UID;
1400         tun->group = INVALID_GID;
1401
1402         dev->ethtool_ops = &tun_ethtool_ops;
1403         dev->destructor = tun_free_netdev;
1404 }
1405
1406 /* Trivial set of netlink ops to allow deleting tun or tap
1407  * device with netlink.
1408  */
1409 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1410 {
1411         return -EINVAL;
1412 }
1413
1414 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1415         .kind           = DRV_NAME,
1416         .priv_size      = sizeof(struct tun_struct),
1417         .setup          = tun_setup,
1418         .validate       = tun_validate,
1419 };
1420
1421 static void tun_sock_write_space(struct sock *sk)
1422 {
1423         struct tun_file *tfile;
1424         wait_queue_head_t *wqueue;
1425
1426         if (!sock_writeable(sk))
1427                 return;
1428
1429         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1430                 return;
1431
1432         wqueue = sk_sleep(sk);
1433         if (wqueue && waitqueue_active(wqueue))
1434                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1435                                                 POLLWRNORM | POLLWRBAND);
1436
1437         tfile = container_of(sk, struct tun_file, sk);
1438         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1439 }
1440
1441 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1442                        struct msghdr *m, size_t total_len)
1443 {
1444         int ret;
1445         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1446         struct tun_struct *tun = __tun_get(tfile);
1447
1448         if (!tun)
1449                 return -EBADFD;
1450         ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len,
1451                            m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1452         tun_put(tun);
1453         return ret;
1454 }
1455
1456
1457 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1458                        struct msghdr *m, size_t total_len,
1459                        int flags)
1460 {
1461         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1462         struct tun_struct *tun = __tun_get(tfile);
1463         int ret;
1464
1465         if (!tun)
1466                 return -EBADFD;
1467
1468         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1469                 return -EINVAL;
1470         ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len,
1471                           flags & MSG_DONTWAIT);
1472         if (ret > total_len) {
1473                 m->msg_flags |= MSG_TRUNC;
1474                 ret = flags & MSG_TRUNC ? ret : total_len;
1475         }
1476         tun_put(tun);
1477         return ret;
1478 }
1479
1480 static int tun_release(struct socket *sock)
1481 {
1482         if (sock->sk)
1483                 sock_put(sock->sk);
1484         return 0;
1485 }
1486
1487 /* Ops structure to mimic raw sockets with tun */
1488 static const struct proto_ops tun_socket_ops = {
1489         .sendmsg = tun_sendmsg,
1490         .recvmsg = tun_recvmsg,
1491         .release = tun_release,
1492 };
1493
1494 static struct proto tun_proto = {
1495         .name           = "tun",
1496         .owner          = THIS_MODULE,
1497         .obj_size       = sizeof(struct tun_file),
1498 };
1499
1500 static int tun_flags(struct tun_struct *tun)
1501 {
1502         int flags = 0;
1503
1504         if (tun->flags & TUN_TUN_DEV)
1505                 flags |= IFF_TUN;
1506         else
1507                 flags |= IFF_TAP;
1508
1509         if (tun->flags & TUN_NO_PI)
1510                 flags |= IFF_NO_PI;
1511
1512         /* This flag has no real effect.  We track the value for backwards
1513          * compatibility.
1514          */
1515         if (tun->flags & TUN_ONE_QUEUE)
1516                 flags |= IFF_ONE_QUEUE;
1517
1518         if (tun->flags & TUN_VNET_HDR)
1519                 flags |= IFF_VNET_HDR;
1520
1521         if (tun->flags & TUN_TAP_MQ)
1522                 flags |= IFF_MULTI_QUEUE;
1523
1524         return flags;
1525 }
1526
1527 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1528                               char *buf)
1529 {
1530         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1531         return sprintf(buf, "0x%x\n", tun_flags(tun));
1532 }
1533
1534 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1535                               char *buf)
1536 {
1537         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1538         return uid_valid(tun->owner)?
1539                 sprintf(buf, "%u\n",
1540                         from_kuid_munged(current_user_ns(), tun->owner)):
1541                 sprintf(buf, "-1\n");
1542 }
1543
1544 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1545                               char *buf)
1546 {
1547         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1548         return gid_valid(tun->group) ?
1549                 sprintf(buf, "%u\n",
1550                         from_kgid_munged(current_user_ns(), tun->group)):
1551                 sprintf(buf, "-1\n");
1552 }
1553
1554 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1555 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1556 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1557
1558 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1559 {
1560         struct tun_struct *tun;
1561         struct tun_file *tfile = file->private_data;
1562         struct net_device *dev;
1563         int err;
1564
1565         dev = __dev_get_by_name(net, ifr->ifr_name);
1566         if (dev) {
1567                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1568                         return -EBUSY;
1569                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1570                         tun = netdev_priv(dev);
1571                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1572                         tun = netdev_priv(dev);
1573                 else
1574                         return -EINVAL;
1575
1576                 if (tun_not_capable(tun))
1577                         return -EPERM;
1578                 err = security_tun_dev_attach(tfile->socket.sk);
1579                 if (err < 0)
1580                         return err;
1581
1582                 err = tun_attach(tun, file);
1583                 if (err < 0)
1584                         return err;
1585
1586                 if (tun->flags & TUN_TAP_MQ &&
1587                     (tun->numqueues + tun->numdisabled > 1))
1588                         return err;
1589         }
1590         else {
1591                 char *name;
1592                 unsigned long flags = 0;
1593
1594                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1595                         return -EPERM;
1596                 err = security_tun_dev_create();
1597                 if (err < 0)
1598                         return err;
1599
1600                 /* Set dev type */
1601                 if (ifr->ifr_flags & IFF_TUN) {
1602                         /* TUN device */
1603                         flags |= TUN_TUN_DEV;
1604                         name = "tun%d";
1605                 } else if (ifr->ifr_flags & IFF_TAP) {
1606                         /* TAP device */
1607                         flags |= TUN_TAP_DEV;
1608                         name = "tap%d";
1609                 } else
1610                         return -EINVAL;
1611
1612                 if (*ifr->ifr_name)
1613                         name = ifr->ifr_name;
1614
1615                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1616                                        tun_setup,
1617                                        MAX_TAP_QUEUES, MAX_TAP_QUEUES);
1618                 if (!dev)
1619                         return -ENOMEM;
1620
1621                 dev_net_set(dev, net);
1622                 dev->rtnl_link_ops = &tun_link_ops;
1623
1624                 tun = netdev_priv(dev);
1625                 tun->dev = dev;
1626                 tun->flags = flags;
1627                 tun->txflt.count = 0;
1628                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1629
1630                 tun->filter_attached = false;
1631                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1632
1633                 spin_lock_init(&tun->lock);
1634
1635                 security_tun_dev_post_create(&tfile->sk);
1636
1637                 tun_net_init(dev);
1638
1639                 err = tun_flow_init(tun);
1640                 if (err < 0)
1641                         goto err_free_dev;
1642
1643                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1644                         TUN_USER_FEATURES;
1645                 dev->features = dev->hw_features;
1646
1647                 INIT_LIST_HEAD(&tun->disabled);
1648                 err = tun_attach(tun, file);
1649                 if (err < 0)
1650                         goto err_free_dev;
1651
1652                 err = register_netdevice(tun->dev);
1653                 if (err < 0)
1654                         goto err_free_dev;
1655
1656                 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1657                     device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1658                     device_create_file(&tun->dev->dev, &dev_attr_group))
1659                         pr_err("Failed to create tun sysfs files\n");
1660
1661                 netif_carrier_on(tun->dev);
1662         }
1663
1664         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1665
1666         if (ifr->ifr_flags & IFF_NO_PI)
1667                 tun->flags |= TUN_NO_PI;
1668         else
1669                 tun->flags &= ~TUN_NO_PI;
1670
1671         /* This flag has no real effect.  We track the value for backwards
1672          * compatibility.
1673          */
1674         if (ifr->ifr_flags & IFF_ONE_QUEUE)
1675                 tun->flags |= TUN_ONE_QUEUE;
1676         else
1677                 tun->flags &= ~TUN_ONE_QUEUE;
1678
1679         if (ifr->ifr_flags & IFF_VNET_HDR)
1680                 tun->flags |= TUN_VNET_HDR;
1681         else
1682                 tun->flags &= ~TUN_VNET_HDR;
1683
1684         if (ifr->ifr_flags & IFF_MULTI_QUEUE)
1685                 tun->flags |= TUN_TAP_MQ;
1686         else
1687                 tun->flags &= ~TUN_TAP_MQ;
1688
1689         /* Make sure persistent devices do not get stuck in
1690          * xoff state.
1691          */
1692         if (netif_running(tun->dev))
1693                 netif_tx_wake_all_queues(tun->dev);
1694
1695         strcpy(ifr->ifr_name, tun->dev->name);
1696         return 0;
1697
1698  err_free_dev:
1699         free_netdev(dev);
1700         return err;
1701 }
1702
1703 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1704                        struct ifreq *ifr)
1705 {
1706         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1707
1708         strcpy(ifr->ifr_name, tun->dev->name);
1709
1710         ifr->ifr_flags = tun_flags(tun);
1711
1712 }
1713
1714 /* This is like a cut-down ethtool ops, except done via tun fd so no
1715  * privs required. */
1716 static int set_offload(struct tun_struct *tun, unsigned long arg)
1717 {
1718         netdev_features_t features = 0;
1719
1720         if (arg & TUN_F_CSUM) {
1721                 features |= NETIF_F_HW_CSUM;
1722                 arg &= ~TUN_F_CSUM;
1723
1724                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1725                         if (arg & TUN_F_TSO_ECN) {
1726                                 features |= NETIF_F_TSO_ECN;
1727                                 arg &= ~TUN_F_TSO_ECN;
1728                         }
1729                         if (arg & TUN_F_TSO4)
1730                                 features |= NETIF_F_TSO;
1731                         if (arg & TUN_F_TSO6)
1732                                 features |= NETIF_F_TSO6;
1733                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1734                 }
1735
1736                 if (arg & TUN_F_UFO) {
1737                         features |= NETIF_F_UFO;
1738                         arg &= ~TUN_F_UFO;
1739                 }
1740         }
1741
1742         /* This gives the user a way to test for new features in future by
1743          * trying to set them. */
1744         if (arg)
1745                 return -EINVAL;
1746
1747         tun->set_features = features;
1748         netdev_update_features(tun->dev);
1749
1750         return 0;
1751 }
1752
1753 static void tun_detach_filter(struct tun_struct *tun, int n)
1754 {
1755         int i;
1756         struct tun_file *tfile;
1757
1758         for (i = 0; i < n; i++) {
1759                 tfile = rcu_dereference_protected(tun->tfiles[i],
1760                                                   lockdep_rtnl_is_held());
1761                 sk_detach_filter(tfile->socket.sk);
1762         }
1763
1764         tun->filter_attached = false;
1765 }
1766
1767 static int tun_attach_filter(struct tun_struct *tun)
1768 {
1769         int i, ret = 0;
1770         struct tun_file *tfile;
1771
1772         for (i = 0; i < tun->numqueues; i++) {
1773                 tfile = rcu_dereference_protected(tun->tfiles[i],
1774                                                   lockdep_rtnl_is_held());
1775                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1776                 if (ret) {
1777                         tun_detach_filter(tun, i);
1778                         return ret;
1779                 }
1780         }
1781
1782         tun->filter_attached = true;
1783         return ret;
1784 }
1785
1786 static void tun_set_sndbuf(struct tun_struct *tun)
1787 {
1788         struct tun_file *tfile;
1789         int i;
1790
1791         for (i = 0; i < tun->numqueues; i++) {
1792                 tfile = rcu_dereference_protected(tun->tfiles[i],
1793                                                 lockdep_rtnl_is_held());
1794                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1795         }
1796 }
1797
1798 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1799 {
1800         struct tun_file *tfile = file->private_data;
1801         struct tun_struct *tun;
1802         int ret = 0;
1803
1804         rtnl_lock();
1805
1806         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1807                 tun = tfile->detached;
1808                 if (!tun)
1809                         ret = -EINVAL;
1810                 else if (tun_not_capable(tun))
1811                         ret = -EPERM;
1812                 else
1813                         ret = tun_attach(tun, file);
1814         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1815                 tun = rcu_dereference_protected(tfile->tun,
1816                                                 lockdep_rtnl_is_held());
1817                 if (!tun || !(tun->flags & TUN_TAP_MQ))
1818                         ret = -EINVAL;
1819                 else
1820                         __tun_detach(tfile, false);
1821         } else
1822                 ret = -EINVAL;
1823
1824         rtnl_unlock();
1825         return ret;
1826 }
1827
1828 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1829                             unsigned long arg, int ifreq_len)
1830 {
1831         struct tun_file *tfile = file->private_data;
1832         struct tun_struct *tun;
1833         void __user* argp = (void __user*)arg;
1834         struct ifreq ifr;
1835         kuid_t owner;
1836         kgid_t group;
1837         int sndbuf;
1838         int vnet_hdr_sz;
1839         int ret;
1840
1841         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1842                 if (copy_from_user(&ifr, argp, ifreq_len))
1843                         return -EFAULT;
1844         } else {
1845                 memset(&ifr, 0, sizeof(ifr));
1846         }
1847         if (cmd == TUNGETFEATURES) {
1848                 /* Currently this just means: "what IFF flags are valid?".
1849                  * This is needed because we never checked for invalid flags on
1850                  * TUNSETIFF. */
1851                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1852                                 IFF_VNET_HDR | IFF_MULTI_QUEUE,
1853                                 (unsigned int __user*)argp);
1854         } else if (cmd == TUNSETQUEUE)
1855                 return tun_set_queue(file, &ifr);
1856
1857         ret = 0;
1858         rtnl_lock();
1859
1860         tun = __tun_get(tfile);
1861         if (cmd == TUNSETIFF && !tun) {
1862                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1863
1864                 ret = tun_set_iff(tfile->net, file, &ifr);
1865
1866                 if (ret)
1867                         goto unlock;
1868
1869                 if (copy_to_user(argp, &ifr, ifreq_len))
1870                         ret = -EFAULT;
1871                 goto unlock;
1872         }
1873
1874         ret = -EBADFD;
1875         if (!tun)
1876                 goto unlock;
1877
1878         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1879
1880         ret = 0;
1881         switch (cmd) {
1882         case TUNGETIFF:
1883                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1884
1885                 if (copy_to_user(argp, &ifr, ifreq_len))
1886                         ret = -EFAULT;
1887                 break;
1888
1889         case TUNSETNOCSUM:
1890                 /* Disable/Enable checksum */
1891
1892                 /* [unimplemented] */
1893                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1894                           arg ? "disabled" : "enabled");
1895                 break;
1896
1897         case TUNSETPERSIST:
1898                 /* Disable/Enable persist mode. Keep an extra reference to the
1899                  * module to prevent the module being unprobed.
1900                  */
1901                 if (arg) {
1902                         tun->flags |= TUN_PERSIST;
1903                         __module_get(THIS_MODULE);
1904                 } else {
1905                         tun->flags &= ~TUN_PERSIST;
1906                         module_put(THIS_MODULE);
1907                 }
1908
1909                 tun_debug(KERN_INFO, tun, "persist %s\n",
1910                           arg ? "enabled" : "disabled");
1911                 break;
1912
1913         case TUNSETOWNER:
1914                 /* Set owner of the device */
1915                 owner = make_kuid(current_user_ns(), arg);
1916                 if (!uid_valid(owner)) {
1917                         ret = -EINVAL;
1918                         break;
1919                 }
1920                 tun->owner = owner;
1921                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
1922                           from_kuid(&init_user_ns, tun->owner));
1923                 break;
1924
1925         case TUNSETGROUP:
1926                 /* Set group of the device */
1927                 group = make_kgid(current_user_ns(), arg);
1928                 if (!gid_valid(group)) {
1929                         ret = -EINVAL;
1930                         break;
1931                 }
1932                 tun->group = group;
1933                 tun_debug(KERN_INFO, tun, "group set to %u\n",
1934                           from_kgid(&init_user_ns, tun->group));
1935                 break;
1936
1937         case TUNSETLINK:
1938                 /* Only allow setting the type when the interface is down */
1939                 if (tun->dev->flags & IFF_UP) {
1940                         tun_debug(KERN_INFO, tun,
1941                                   "Linktype set failed because interface is up\n");
1942                         ret = -EBUSY;
1943                 } else {
1944                         tun->dev->type = (int) arg;
1945                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1946                                   tun->dev->type);
1947                         ret = 0;
1948                 }
1949                 break;
1950
1951 #ifdef TUN_DEBUG
1952         case TUNSETDEBUG:
1953                 tun->debug = arg;
1954                 break;
1955 #endif
1956         case TUNSETOFFLOAD:
1957                 ret = set_offload(tun, arg);
1958                 break;
1959
1960         case TUNSETTXFILTER:
1961                 /* Can be set only for TAPs */
1962                 ret = -EINVAL;
1963                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1964                         break;
1965                 ret = update_filter(&tun->txflt, (void __user *)arg);
1966                 break;
1967
1968         case SIOCGIFHWADDR:
1969                 /* Get hw address */
1970                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1971                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1972                 if (copy_to_user(argp, &ifr, ifreq_len))
1973                         ret = -EFAULT;
1974                 break;
1975
1976         case SIOCSIFHWADDR:
1977                 /* Set hw address */
1978                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1979                           ifr.ifr_hwaddr.sa_data);
1980
1981                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1982                 break;
1983
1984         case TUNGETSNDBUF:
1985                 sndbuf = tfile->socket.sk->sk_sndbuf;
1986                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1987                         ret = -EFAULT;
1988                 break;
1989
1990         case TUNSETSNDBUF:
1991                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1992                         ret = -EFAULT;
1993                         break;
1994                 }
1995
1996                 tun->sndbuf = sndbuf;
1997                 tun_set_sndbuf(tun);
1998                 break;
1999
2000         case TUNGETVNETHDRSZ:
2001                 vnet_hdr_sz = tun->vnet_hdr_sz;
2002                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2003                         ret = -EFAULT;
2004                 break;
2005
2006         case TUNSETVNETHDRSZ:
2007                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2008                         ret = -EFAULT;
2009                         break;
2010                 }
2011                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2012                         ret = -EINVAL;
2013                         break;
2014                 }
2015
2016                 tun->vnet_hdr_sz = vnet_hdr_sz;
2017                 break;
2018
2019         case TUNATTACHFILTER:
2020                 /* Can be set only for TAPs */
2021                 ret = -EINVAL;
2022                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2023                         break;
2024                 ret = -EFAULT;
2025                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2026                         break;
2027
2028                 ret = tun_attach_filter(tun);
2029                 break;
2030
2031         case TUNDETACHFILTER:
2032                 /* Can be set only for TAPs */
2033                 ret = -EINVAL;
2034                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2035                         break;
2036                 ret = 0;
2037                 tun_detach_filter(tun, tun->numqueues);
2038                 break;
2039
2040         default:
2041                 ret = -EINVAL;
2042                 break;
2043         }
2044
2045 unlock:
2046         rtnl_unlock();
2047         if (tun)
2048                 tun_put(tun);
2049         return ret;
2050 }
2051
2052 static long tun_chr_ioctl(struct file *file,
2053                           unsigned int cmd, unsigned long arg)
2054 {
2055         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2056 }
2057
2058 #ifdef CONFIG_COMPAT
2059 static long tun_chr_compat_ioctl(struct file *file,
2060                          unsigned int cmd, unsigned long arg)
2061 {
2062         switch (cmd) {
2063         case TUNSETIFF:
2064         case TUNGETIFF:
2065         case TUNSETTXFILTER:
2066         case TUNGETSNDBUF:
2067         case TUNSETSNDBUF:
2068         case SIOCGIFHWADDR:
2069         case SIOCSIFHWADDR:
2070                 arg = (unsigned long)compat_ptr(arg);
2071                 break;
2072         default:
2073                 arg = (compat_ulong_t)arg;
2074                 break;
2075         }
2076
2077         /*
2078          * compat_ifreq is shorter than ifreq, so we must not access beyond
2079          * the end of that structure. All fields that are used in this
2080          * driver are compatible though, we don't need to convert the
2081          * contents.
2082          */
2083         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2084 }
2085 #endif /* CONFIG_COMPAT */
2086
2087 static int tun_chr_fasync(int fd, struct file *file, int on)
2088 {
2089         struct tun_file *tfile = file->private_data;
2090         int ret;
2091
2092         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2093                 goto out;
2094
2095         if (on) {
2096                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2097                 if (ret)
2098                         goto out;
2099                 tfile->flags |= TUN_FASYNC;
2100         } else
2101                 tfile->flags &= ~TUN_FASYNC;
2102         ret = 0;
2103 out:
2104         return ret;
2105 }
2106
2107 static int tun_chr_open(struct inode *inode, struct file * file)
2108 {
2109         struct tun_file *tfile;
2110
2111         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2112
2113         tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
2114                                             &tun_proto);
2115         if (!tfile)
2116                 return -ENOMEM;
2117         rcu_assign_pointer(tfile->tun, NULL);
2118         tfile->net = get_net(current->nsproxy->net_ns);
2119         tfile->flags = 0;
2120
2121         rcu_assign_pointer(tfile->socket.wq, &tfile->wq);
2122         init_waitqueue_head(&tfile->wq.wait);
2123
2124         tfile->socket.file = file;
2125         tfile->socket.ops = &tun_socket_ops;
2126
2127         sock_init_data(&tfile->socket, &tfile->sk);
2128         sk_change_net(&tfile->sk, tfile->net);
2129
2130         tfile->sk.sk_write_space = tun_sock_write_space;
2131         tfile->sk.sk_sndbuf = INT_MAX;
2132
2133         file->private_data = tfile;
2134         set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
2135         INIT_LIST_HEAD(&tfile->next);
2136
2137         return 0;
2138 }
2139
2140 static int tun_chr_close(struct inode *inode, struct file *file)
2141 {
2142         struct tun_file *tfile = file->private_data;
2143         struct net *net = tfile->net;
2144
2145         tun_detach(tfile, true);
2146         put_net(net);
2147
2148         return 0;
2149 }
2150
2151 static const struct file_operations tun_fops = {
2152         .owner  = THIS_MODULE,
2153         .llseek = no_llseek,
2154         .read  = do_sync_read,
2155         .aio_read  = tun_chr_aio_read,
2156         .write = do_sync_write,
2157         .aio_write = tun_chr_aio_write,
2158         .poll   = tun_chr_poll,
2159         .unlocked_ioctl = tun_chr_ioctl,
2160 #ifdef CONFIG_COMPAT
2161         .compat_ioctl = tun_chr_compat_ioctl,
2162 #endif
2163         .open   = tun_chr_open,
2164         .release = tun_chr_close,
2165         .fasync = tun_chr_fasync
2166 };
2167
2168 static struct miscdevice tun_miscdev = {
2169         .minor = TUN_MINOR,
2170         .name = "tun",
2171         .nodename = "net/tun",
2172         .fops = &tun_fops,
2173 };
2174
2175 /* ethtool interface */
2176
2177 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2178 {
2179         cmd->supported          = 0;
2180         cmd->advertising        = 0;
2181         ethtool_cmd_speed_set(cmd, SPEED_10);
2182         cmd->duplex             = DUPLEX_FULL;
2183         cmd->port               = PORT_TP;
2184         cmd->phy_address        = 0;
2185         cmd->transceiver        = XCVR_INTERNAL;
2186         cmd->autoneg            = AUTONEG_DISABLE;
2187         cmd->maxtxpkt           = 0;
2188         cmd->maxrxpkt           = 0;
2189         return 0;
2190 }
2191
2192 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2193 {
2194         struct tun_struct *tun = netdev_priv(dev);
2195
2196         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2197         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2198
2199         switch (tun->flags & TUN_TYPE_MASK) {
2200         case TUN_TUN_DEV:
2201                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2202                 break;
2203         case TUN_TAP_DEV:
2204                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2205                 break;
2206         }
2207 }
2208
2209 static u32 tun_get_msglevel(struct net_device *dev)
2210 {
2211 #ifdef TUN_DEBUG
2212         struct tun_struct *tun = netdev_priv(dev);
2213         return tun->debug;
2214 #else
2215         return -EOPNOTSUPP;
2216 #endif
2217 }
2218
2219 static void tun_set_msglevel(struct net_device *dev, u32 value)
2220 {
2221 #ifdef TUN_DEBUG
2222         struct tun_struct *tun = netdev_priv(dev);
2223         tun->debug = value;
2224 #endif
2225 }
2226
2227 static const struct ethtool_ops tun_ethtool_ops = {
2228         .get_settings   = tun_get_settings,
2229         .get_drvinfo    = tun_get_drvinfo,
2230         .get_msglevel   = tun_get_msglevel,
2231         .set_msglevel   = tun_set_msglevel,
2232         .get_link       = ethtool_op_get_link,
2233 };
2234
2235
2236 static int __init tun_init(void)
2237 {
2238         int ret = 0;
2239
2240         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2241         pr_info("%s\n", DRV_COPYRIGHT);
2242
2243         ret = rtnl_link_register(&tun_link_ops);
2244         if (ret) {
2245                 pr_err("Can't register link_ops\n");
2246                 goto err_linkops;
2247         }
2248
2249         ret = misc_register(&tun_miscdev);
2250         if (ret) {
2251                 pr_err("Can't register misc device %d\n", TUN_MINOR);
2252                 goto err_misc;
2253         }
2254         return  0;
2255 err_misc:
2256         rtnl_link_unregister(&tun_link_ops);
2257 err_linkops:
2258         return ret;
2259 }
2260
2261 static void tun_cleanup(void)
2262 {
2263         misc_deregister(&tun_miscdev);
2264         rtnl_link_unregister(&tun_link_ops);
2265 }
2266
2267 /* Get an underlying socket object from tun file.  Returns error unless file is
2268  * attached to a device.  The returned object works like a packet socket, it
2269  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2270  * holding a reference to the file for as long as the socket is in use. */
2271 struct socket *tun_get_socket(struct file *file)
2272 {
2273         struct tun_file *tfile;
2274         if (file->f_op != &tun_fops)
2275                 return ERR_PTR(-EINVAL);
2276         tfile = file->private_data;
2277         if (!tfile)
2278                 return ERR_PTR(-EBADFD);
2279         return &tfile->socket;
2280 }
2281 EXPORT_SYMBOL_GPL(tun_get_socket);
2282
2283 module_init(tun_init);
2284 module_exit(tun_cleanup);
2285 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2286 MODULE_AUTHOR(DRV_COPYRIGHT);
2287 MODULE_LICENSE("GPL");
2288 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2289 MODULE_ALIAS("devname:net/tun");