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 };
 142
 143 struct tun_flow_entry {
 144         struct hlist_node hash_link;
 145         struct rcu_head rcu;
 146         struct tun_struct *tun;
 147
 148         u32 rxhash;
 149         int queue_index;
 150         unsigned long updated;
 151 };
 152
 153 #define TUN_NUM_FLOW_ENTRIES 1024
 154
 155 /* Since the socket were moved to tun_file, to preserve the behavior of persist
 156  * device, socket filter, sndbuf and vnet header size were restore when the
 157  * file were attached to a persist device.
 158  */
 159 struct tun_struct {
 160         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
 161         unsigned int            numqueues;
 162         unsigned int            flags;
 163         kuid_t                  owner;
 164         kgid_t                  group;
 165
 166         struct net_device       *dev;
 167         netdev_features_t       set_features;
 168 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 169                           NETIF_F_TSO6|NETIF_F_UFO)
 170
 171         int                     vnet_hdr_sz;
 172         int                     sndbuf;
 173         struct tap_filter       txflt;
 174         struct sock_fprog       fprog;
 175         /* protected by rtnl lock */
 176         bool                    filter_attached;
 177 #ifdef TUN_DEBUG
 178         int debug;
 179 #endif
 180         spinlock_t lock;
 181         struct kmem_cache *flow_cache;
 182         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 183         struct timer_list flow_gc_timer;
 184         unsigned long ageing_time;
 185 };
 186
 187 static inline u32 tun_hashfn(u32 rxhash)
 188 {
 189         return rxhash & 0x3ff;
 190 }
 191
 192 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 193 {
 194         struct tun_flow_entry *e;
 195         struct hlist_node *n;
 196
 197         hlist_for_each_entry_rcu(e, n, head, hash_link) {
 198                 if (e->rxhash == rxhash)
 199                         return e;
 200         }
 201         return NULL;
 202 }
 203
 204 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 205                                               struct hlist_head *head,
 206                                               u32 rxhash, u16 queue_index)
 207 {
 208         struct tun_flow_entry *e = kmem_cache_alloc(tun->flow_cache,
 209                                                     GFP_ATOMIC);
 210         if (e) {
 211                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 212                           rxhash, queue_index);
 213                 e->updated = jiffies;
 214                 e->rxhash = rxhash;
 215                 e->queue_index = queue_index;
 216                 e->tun = tun;
 217                 hlist_add_head_rcu(&e->hash_link, head);
 218         }
 219         return e;
 220 }
 221
 222 static void tun_flow_free(struct rcu_head *head)
 223 {
 224         struct tun_flow_entry *e
 225                 = container_of(head, struct tun_flow_entry, rcu);
 226         kmem_cache_free(e->tun->flow_cache, e);
 227 }
 228
 229 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 230 {
 231         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 232                   e->rxhash, e->queue_index);
 233         hlist_del_rcu(&e->hash_link);
 234         call_rcu(&e->rcu, tun_flow_free);
 235 }
 236
 237 static void tun_flow_flush(struct tun_struct *tun)
 238 {
 239         int i;
 240
 241         spin_lock_bh(&tun->lock);
 242         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 243                 struct tun_flow_entry *e;
 244                 struct hlist_node *h, *n;
 245
 246                 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link)
 247                         tun_flow_delete(tun, e);
 248         }
 249         spin_unlock_bh(&tun->lock);
 250 }
 251
 252 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 253 {
 254         int i;
 255
 256         spin_lock_bh(&tun->lock);
 257         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 258                 struct tun_flow_entry *e;
 259                 struct hlist_node *h, *n;
 260
 261                 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link) {
 262                         if (e->queue_index == queue_index)
 263                                 tun_flow_delete(tun, e);
 264                 }
 265         }
 266         spin_unlock_bh(&tun->lock);
 267 }
 268
 269 static void tun_flow_cleanup(unsigned long data)
 270 {
 271         struct tun_struct *tun = (struct tun_struct *)data;
 272         unsigned long delay = tun->ageing_time;
 273         unsigned long next_timer = jiffies + delay;
 274         unsigned long count = 0;
 275         int i;
 276
 277         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 278
 279         spin_lock_bh(&tun->lock);
 280         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 281                 struct tun_flow_entry *e;
 282                 struct hlist_node *h, *n;
 283
 284                 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link) {
 285                         unsigned long this_timer;
 286                         count++;
 287                         this_timer = e->updated + delay;
 288                         if (time_before_eq(this_timer, jiffies))
 289                                 tun_flow_delete(tun, e);
 290                         else if (time_before(this_timer, next_timer))
 291                                 next_timer = this_timer;
 292                 }
 293         }
 294
 295         if (count)
 296                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 297         spin_unlock_bh(&tun->lock);
 298 }
 299
 300 static void tun_flow_update(struct tun_struct *tun, struct sk_buff *skb,
 301                             u16 queue_index)
 302 {
 303         struct hlist_head *head;
 304         struct tun_flow_entry *e;
 305         unsigned long delay = tun->ageing_time;
 306         u32 rxhash = skb_get_rxhash(skb);
 307
 308         if (!rxhash)
 309                 return;
 310         else
 311                 head = &tun->flows[tun_hashfn(rxhash)];
 312
 313         rcu_read_lock();
 314
 315         if (tun->numqueues == 1)
 316                 goto unlock;
 317
 318         e = tun_flow_find(head, rxhash);
 319         if (likely(e)) {
 320                 /* TODO: keep queueing to old queue until it's empty? */
 321                 e->queue_index = queue_index;
 322                 e->updated = jiffies;
 323         } else {
 324                 spin_lock_bh(&tun->lock);
 325                 if (!tun_flow_find(head, rxhash))
 326                         tun_flow_create(tun, head, rxhash, queue_index);
 327
 328                 if (!timer_pending(&tun->flow_gc_timer))
 329                         mod_timer(&tun->flow_gc_timer,
 330                                   round_jiffies_up(jiffies + delay));
 331                 spin_unlock_bh(&tun->lock);
 332         }
 333
 334 unlock:
 335         rcu_read_unlock();
 336 }
 337
 338 /* We try to identify a flow through its rxhash first. The reason that
 339  * we do not check rxq no. is becuase some cards(e.g 82599), chooses
 340  * the rxq based on the txq where the last packet of the flow comes. As
 341  * the userspace application move between processors, we may get a
 342  * different rxq no. here. If we could not get rxhash, then we would
 343  * hope the rxq no. may help here.
 344  */
 345 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb)
 346 {
 347         struct tun_struct *tun = netdev_priv(dev);
 348         struct tun_flow_entry *e;
 349         u32 txq = 0;
 350         u32 numqueues = 0;
 351
 352         rcu_read_lock();
 353         numqueues = tun->numqueues;
 354
 355         txq = skb_get_rxhash(skb);
 356         if (txq) {
 357                 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 358                 if (e)
 359                         txq = e->queue_index;
 360                 else
 361                         /* use multiply and shift instead of expensive divide */
 362                         txq = ((u64)txq * numqueues) >> 32;
 363         } else if (likely(skb_rx_queue_recorded(skb))) {
 364                 txq = skb_get_rx_queue(skb);
 365                 while (unlikely(txq >= numqueues))
 366                         txq -= numqueues;
 367         }
 368
 369         rcu_read_unlock();
 370         return txq;
 371 }
 372
 373 static inline bool tun_not_capable(struct tun_struct *tun)
 374 {
 375         const struct cred *cred = current_cred();
 376         struct net *net = dev_net(tun->dev);
 377
 378         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 379                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 380                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 381 }
 382
 383 static void tun_set_real_num_queues(struct tun_struct *tun)
 384 {
 385         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 386         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 387 }
 388
 389 static void __tun_detach(struct tun_file *tfile, bool clean)
 390 {
 391         struct tun_file *ntfile;
 392         struct tun_struct *tun;
 393         struct net_device *dev;
 394
 395         tun = rcu_dereference_protected(tfile->tun,
 396                                         lockdep_rtnl_is_held());
 397         if (tun) {
 398                 u16 index = tfile->queue_index;
 399                 BUG_ON(index >= tun->numqueues);
 400                 dev = tun->dev;
 401
 402                 rcu_assign_pointer(tun->tfiles[index],
 403                                    tun->tfiles[tun->numqueues - 1]);
 404                 rcu_assign_pointer(tfile->tun, NULL);
 405                 ntfile = rcu_dereference_protected(tun->tfiles[index],
 406                                                    lockdep_rtnl_is_held());
 407                 ntfile->queue_index = index;
 408
 409                 --tun->numqueues;
 410                 sock_put(&tfile->sk);
 411
 412                 synchronize_net();
 413                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 414                 /* Drop read queue */
 415                 skb_queue_purge(&tfile->sk.sk_receive_queue);
 416                 tun_set_real_num_queues(tun);
 417
 418                 if (tun->numqueues == 0 && !(tun->flags & TUN_PERSIST))
 419                         if (dev->reg_state == NETREG_REGISTERED)
 420                                 unregister_netdevice(dev);
 421         }
 422
 423         if (clean) {
 424                 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
 425                                  &tfile->socket.flags));
 426                 sk_release_kernel(&tfile->sk);
 427         }
 428 }
 429
 430 static void tun_detach(struct tun_file *tfile, bool clean)
 431 {
 432         rtnl_lock();
 433         __tun_detach(tfile, clean);
 434         rtnl_unlock();
 435 }
 436
 437 static void tun_detach_all(struct net_device *dev)
 438 {
 439         struct tun_struct *tun = netdev_priv(dev);
 440         struct tun_file *tfile;
 441         int i, n = tun->numqueues;
 442
 443         for (i = 0; i < n; i++) {
 444                 tfile = rcu_dereference_protected(tun->tfiles[i],
 445                                                   lockdep_rtnl_is_held());
 446                 BUG_ON(!tfile);
 447                 wake_up_all(&tfile->wq.wait);
 448                 rcu_assign_pointer(tfile->tun, NULL);
 449                 --tun->numqueues;
 450         }
 451         BUG_ON(tun->numqueues != 0);
 452
 453         synchronize_net();
 454         for (i = 0; i < n; i++) {
 455                 tfile = rcu_dereference_protected(tun->tfiles[i],
 456                                                   lockdep_rtnl_is_held());
 457                 /* Drop read queue */
 458                 skb_queue_purge(&tfile->sk.sk_receive_queue);
 459                 sock_put(&tfile->sk);
 460         }
 461 }
 462
 463 static int tun_attach(struct tun_struct *tun, struct file *file)
 464 {
 465         struct tun_file *tfile = file->private_data;
 466         int err;
 467
 468         err = -EINVAL;
 469         if (rcu_dereference_protected(tfile->tun, lockdep_rtnl_is_held()))
 470                 goto out;
 471
 472         err = -EBUSY;
 473         if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1)
 474                 goto out;
 475
 476         err = -E2BIG;
 477         if (tun->numqueues == MAX_TAP_QUEUES)
 478                 goto out;
 479
 480         err = 0;
 481
 482         /* Re-attach the filter to presist device */
 483         if (tun->filter_attached == true) {
 484                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 485                 if (!err)
 486                         goto out;
 487         }
 488         tfile->queue_index = tun->numqueues;
 489         rcu_assign_pointer(tfile->tun, tun);
 490         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 491         sock_hold(&tfile->sk);
 492         tun->numqueues++;
 493
 494         tun_set_real_num_queues(tun);
 495
 496         /* device is allowed to go away first, so no need to hold extra
 497          * refcnt.
 498          */
 499
 500 out:
 501         return err;
 502 }
 503
 504 static struct tun_struct *__tun_get(struct tun_file *tfile)
 505 {
 506         struct tun_struct *tun;
 507
 508         rcu_read_lock();
 509         tun = rcu_dereference(tfile->tun);
 510         if (tun)
 511                 dev_hold(tun->dev);
 512         rcu_read_unlock();
 513
 514         return tun;
 515 }
 516
 517 static struct tun_struct *tun_get(struct file *file)
 518 {
 519         return __tun_get(file->private_data);
 520 }
 521
 522 static void tun_put(struct tun_struct *tun)
 523 {
 524         dev_put(tun->dev);
 525 }
 526
 527 /* TAP filtering */
 528 static void addr_hash_set(u32 *mask, const u8 *addr)
 529 {
 530         int n = ether_crc(ETH_ALEN, addr) >> 26;
 531         mask[n >> 5] |= (1 << (n & 31));
 532 }
 533
 534 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 535 {
 536         int n = ether_crc(ETH_ALEN, addr) >> 26;
 537         return mask[n >> 5] & (1 << (n & 31));
 538 }
 539
 540 static int update_filter(struct tap_filter *filter, void __user *arg)
 541 {
 542         struct { u8 u[ETH_ALEN]; } *addr;
 543         struct tun_filter uf;
 544         int err, alen, n, nexact;
 545
 546         if (copy_from_user(&uf, arg, sizeof(uf)))
 547                 return -EFAULT;
 548
 549         if (!uf.count) {
 550                 /* Disabled */
 551                 filter->count = 0;
 552                 return 0;
 553         }
 554
 555         alen = ETH_ALEN * uf.count;
 556         addr = kmalloc(alen, GFP_KERNEL);
 557         if (!addr)
 558                 return -ENOMEM;
 559
 560         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 561                 err = -EFAULT;
 562                 goto done;
 563         }
 564
 565         /* The filter is updated without holding any locks. Which is
 566          * perfectly safe. We disable it first and in the worst
 567          * case we'll accept a few undesired packets. */
 568         filter->count = 0;
 569         wmb();
 570
 571         /* Use first set of addresses as an exact filter */
 572         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 573                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 574
 575         nexact = n;
 576
 577         /* Remaining multicast addresses are hashed,
 578          * unicast will leave the filter disabled. */
 579         memset(filter->mask, 0, sizeof(filter->mask));
 580         for (; n < uf.count; n++) {
 581                 if (!is_multicast_ether_addr(addr[n].u)) {
 582                         err = 0; /* no filter */
 583                         goto done;
 584                 }
 585                 addr_hash_set(filter->mask, addr[n].u);
 586         }
 587
 588         /* For ALLMULTI just set the mask to all ones.
 589          * This overrides the mask populated above. */
 590         if ((uf.flags & TUN_FLT_ALLMULTI))
 591                 memset(filter->mask, ~0, sizeof(filter->mask));
 592
 593         /* Now enable the filter */
 594         wmb();
 595         filter->count = nexact;
 596
 597         /* Return the number of exact filters */
 598         err = nexact;
 599
 600 done:
 601         kfree(addr);
 602         return err;
 603 }
 604
 605 /* Returns: 0 - drop, !=0 - accept */
 606 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 607 {
 608         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 609          * at this point. */
 610         struct ethhdr *eh = (struct ethhdr *) skb->data;
 611         int i;
 612
 613         /* Exact match */
 614         for (i = 0; i < filter->count; i++)
 615                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 616                         return 1;
 617
 618         /* Inexact match (multicast only) */
 619         if (is_multicast_ether_addr(eh->h_dest))
 620                 return addr_hash_test(filter->mask, eh->h_dest);
 621
 622         return 0;
 623 }
 624
 625 /*
 626  * Checks whether the packet is accepted or not.
 627  * Returns: 0 - drop, !=0 - accept
 628  */
 629 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 630 {
 631         if (!filter->count)
 632                 return 1;
 633
 634         return run_filter(filter, skb);
 635 }
 636
 637 /* Network device part of the driver */
 638
 639 static const struct ethtool_ops tun_ethtool_ops;
 640
 641 /* Net device detach from fd. */
 642 static void tun_net_uninit(struct net_device *dev)
 643 {
 644         tun_detach_all(dev);
 645 }
 646
 647 /* Net device open. */
 648 static int tun_net_open(struct net_device *dev)
 649 {
 650         netif_tx_start_all_queues(dev);
 651         return 0;
 652 }
 653
 654 /* Net device close. */
 655 static int tun_net_close(struct net_device *dev)
 656 {
 657         netif_tx_stop_all_queues(dev);
 658         return 0;
 659 }
 660
 661 /* Net device start xmit */
 662 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 663 {
 664         struct tun_struct *tun = netdev_priv(dev);
 665         int txq = skb->queue_mapping;
 666         struct tun_file *tfile;
 667
 668         rcu_read_lock();
 669         tfile = rcu_dereference(tun->tfiles[txq]);
 670
 671         /* Drop packet if interface is not attached */
 672         if (txq >= tun->numqueues)
 673                 goto drop;
 674
 675         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 676
 677         BUG_ON(!tfile);
 678
 679         /* Drop if the filter does not like it.
 680          * This is a noop if the filter is disabled.
 681          * Filter can be enabled only for the TAP devices. */
 682         if (!check_filter(&tun->txflt, skb))
 683                 goto drop;
 684
 685         if (tfile->socket.sk->sk_filter &&
 686             sk_filter(tfile->socket.sk, skb))
 687                 goto drop;
 688
 689         /* Limit the number of packets queued by dividing txq length with the
 690          * number of queues.
 691          */
 692         if (skb_queue_len(&tfile->socket.sk->sk_receive_queue)
 693                           >= dev->tx_queue_len / tun->numqueues)
 694                 goto drop;
 695
 696         /* Orphan the skb - required as we might hang on to it
 697          * for indefinite time. */
 698         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 699                 goto drop;
 700         skb_orphan(skb);
 701
 702         /* Enqueue packet */
 703         skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
 704
 705         /* Notify and wake up reader process */
 706         if (tfile->flags & TUN_FASYNC)
 707                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
 708         wake_up_interruptible_poll(&tfile->wq.wait, POLLIN |
 709                                    POLLRDNORM | POLLRDBAND);
 710
 711         rcu_read_unlock();
 712         return NETDEV_TX_OK;
 713
 714 drop:
 715         dev->stats.tx_dropped++;
 716         skb_tx_error(skb);
 717         kfree_skb(skb);
 718         rcu_read_unlock();
 719         return NETDEV_TX_OK;
 720 }
 721
 722 static void tun_net_mclist(struct net_device *dev)
 723 {
 724         /*
 725          * This callback is supposed to deal with mc filter in
 726          * _rx_ path and has nothing to do with the _tx_ path.
 727          * In rx path we always accept everything userspace gives us.
 728          */
 729 }
 730
 731 #define MIN_MTU 68
 732 #define MAX_MTU 65535
 733
 734 static int
 735 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 736 {
 737         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 738                 return -EINVAL;
 739         dev->mtu = new_mtu;
 740         return 0;
 741 }
 742
 743 static netdev_features_t tun_net_fix_features(struct net_device *dev,
 744         netdev_features_t features)
 745 {
 746         struct tun_struct *tun = netdev_priv(dev);
 747
 748         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 749 }
 750 #ifdef CONFIG_NET_POLL_CONTROLLER
 751 static void tun_poll_controller(struct net_device *dev)
 752 {
 753         /*
 754          * Tun only receives frames when:
 755          * 1) the char device endpoint gets data from user space
 756          * 2) the tun socket gets a sendmsg call from user space
 757          * Since both of those are syncronous operations, we are guaranteed
 758          * never to have pending data when we poll for it
 759          * so theres nothing to do here but return.
 760          * We need this though so netpoll recognizes us as an interface that
 761          * supports polling, which enables bridge devices in virt setups to
 762          * still use netconsole
 763          */
 764         return;
 765 }
 766 #endif
 767 static const struct net_device_ops tun_netdev_ops = {
 768         .ndo_uninit             = tun_net_uninit,
 769         .ndo_open               = tun_net_open,
 770         .ndo_stop               = tun_net_close,
 771         .ndo_start_xmit         = tun_net_xmit,
 772         .ndo_change_mtu         = tun_net_change_mtu,
 773         .ndo_fix_features       = tun_net_fix_features,
 774         .ndo_select_queue       = tun_select_queue,
 775 #ifdef CONFIG_NET_POLL_CONTROLLER
 776         .ndo_poll_controller    = tun_poll_controller,
 777 #endif
 778 };
 779
 780 static const struct net_device_ops tap_netdev_ops = {
 781         .ndo_uninit             = tun_net_uninit,
 782         .ndo_open               = tun_net_open,
 783         .ndo_stop               = tun_net_close,
 784         .ndo_start_xmit         = tun_net_xmit,
 785         .ndo_change_mtu         = tun_net_change_mtu,
 786         .ndo_fix_features       = tun_net_fix_features,
 787         .ndo_set_rx_mode        = tun_net_mclist,
 788         .ndo_set_mac_address    = eth_mac_addr,
 789         .ndo_validate_addr      = eth_validate_addr,
 790         .ndo_select_queue       = tun_select_queue,
 791 #ifdef CONFIG_NET_POLL_CONTROLLER
 792         .ndo_poll_controller    = tun_poll_controller,
 793 #endif
 794 };
 795
 796 static int tun_flow_init(struct tun_struct *tun)
 797 {
 798         int i;
 799
 800         tun->flow_cache = kmem_cache_create("tun_flow_cache",
 801                                             sizeof(struct tun_flow_entry), 0, 0,
 802                                             NULL);
 803         if (!tun->flow_cache)
 804                 return -ENOMEM;
 805
 806         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
 807                 INIT_HLIST_HEAD(&tun->flows[i]);
 808
 809         tun->ageing_time = TUN_FLOW_EXPIRE;
 810         setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
 811         mod_timer(&tun->flow_gc_timer,
 812                   round_jiffies_up(jiffies + tun->ageing_time));
 813
 814         return 0;
 815 }
 816
 817 static void tun_flow_uninit(struct tun_struct *tun)
 818 {
 819         del_timer_sync(&tun->flow_gc_timer);
 820         tun_flow_flush(tun);
 821
 822         /* Wait for completion of call_rcu()'s */
 823         rcu_barrier();
 824         kmem_cache_destroy(tun->flow_cache);
 825 }
 826
 827 /* Initialize net device. */
 828 static void tun_net_init(struct net_device *dev)
 829 {
 830         struct tun_struct *tun = netdev_priv(dev);
 831
 832         switch (tun->flags & TUN_TYPE_MASK) {
 833         case TUN_TUN_DEV:
 834                 dev->netdev_ops = &tun_netdev_ops;
 835
 836                 /* Point-to-Point TUN Device */
 837                 dev->hard_header_len = 0;
 838                 dev->addr_len = 0;
 839                 dev->mtu = 1500;
 840
 841                 /* Zero header length */
 842                 dev->type = ARPHRD_NONE;
 843                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 844                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 845                 break;
 846
 847         case TUN_TAP_DEV:
 848                 dev->netdev_ops = &tap_netdev_ops;
 849                 /* Ethernet TAP Device */
 850                 ether_setup(dev);
 851                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 852
 853                 eth_hw_addr_random(dev);
 854
 855                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 856                 break;
 857         }
 858 }
 859
 860 /* Character device part */
 861
 862 /* Poll */
 863 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
 864 {
 865         struct tun_file *tfile = file->private_data;
 866         struct tun_struct *tun = __tun_get(tfile);
 867         struct sock *sk;
 868         unsigned int mask = 0;
 869
 870         if (!tun)
 871                 return POLLERR;
 872
 873         sk = tfile->socket.sk;
 874
 875         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
 876
 877         poll_wait(file, &tfile->wq.wait, wait);
 878
 879         if (!skb_queue_empty(&sk->sk_receive_queue))
 880                 mask |= POLLIN | POLLRDNORM;
 881
 882         if (sock_writeable(sk) ||
 883             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 884              sock_writeable(sk)))
 885                 mask |= POLLOUT | POLLWRNORM;
 886
 887         if (tun->dev->reg_state != NETREG_REGISTERED)
 888                 mask = POLLERR;
 889
 890         tun_put(tun);
 891         return mask;
 892 }
 893
 894 /* prepad is the amount to reserve at front.  len is length after that.
 895  * linear is a hint as to how much to copy (usually headers). */
 896 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
 897                                      size_t prepad, size_t len,
 898                                      size_t linear, int noblock)
 899 {
 900         struct sock *sk = tfile->socket.sk;
 901         struct sk_buff *skb;
 902         int err;
 903
 904         /* Under a page?  Don't bother with paged skb. */
 905         if (prepad + len < PAGE_SIZE || !linear)
 906                 linear = len;
 907
 908         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 909                                    &err);
 910         if (!skb)
 911                 return ERR_PTR(err);
 912
 913         skb_reserve(skb, prepad);
 914         skb_put(skb, linear);
 915         skb->data_len = len - linear;
 916         skb->len += len - linear;
 917
 918         return skb;
 919 }
 920
 921 /* set skb frags from iovec, this can move to core network code for reuse */
 922 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
 923                                   int offset, size_t count)
 924 {
 925         int len = iov_length(from, count) - offset;
 926         int copy = skb_headlen(skb);
 927         int size, offset1 = 0;
 928         int i = 0;
 929
 930         /* Skip over from offset */
 931         while (count && (offset >= from->iov_len)) {
 932                 offset -= from->iov_len;
 933                 ++from;
 934                 --count;
 935         }
 936
 937         /* copy up to skb headlen */
 938         while (count && (copy > 0)) {
 939                 size = min_t(unsigned int, copy, from->iov_len - offset);
 940                 if (copy_from_user(skb->data + offset1, from->iov_base + offset,
 941                                    size))
 942                         return -EFAULT;
 943                 if (copy > size) {
 944                         ++from;
 945                         --count;
 946                         offset = 0;
 947                 } else
 948                         offset += size;
 949                 copy -= size;
 950                 offset1 += size;
 951         }
 952
 953         if (len == offset1)
 954                 return 0;
 955
 956         while (count--) {
 957                 struct page *page[MAX_SKB_FRAGS];
 958                 int num_pages;
 959                 unsigned long base;
 960                 unsigned long truesize;
 961
 962                 len = from->iov_len - offset;
 963                 if (!len) {
 964                         offset = 0;
 965                         ++from;
 966                         continue;
 967                 }
 968                 base = (unsigned long)from->iov_base + offset;
 969                 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
 970                 if (i + size > MAX_SKB_FRAGS)
 971                         return -EMSGSIZE;
 972                 num_pages = get_user_pages_fast(base, size, 0, &page[i]);
 973                 if (num_pages != size) {
 974                         for (i = 0; i < num_pages; i++)
 975                                 put_page(page[i]);
 976                         return -EFAULT;
 977                 }
 978                 truesize = size * PAGE_SIZE;
 979                 skb->data_len += len;
 980                 skb->len += len;
 981                 skb->truesize += truesize;
 982                 atomic_add(truesize, &skb->sk->sk_wmem_alloc);
 983                 while (len) {
 984                         int off = base & ~PAGE_MASK;
 985                         int size = min_t(int, len, PAGE_SIZE - off);
 986                         __skb_fill_page_desc(skb, i, page[i], off, size);
 987                         skb_shinfo(skb)->nr_frags++;
 988                         /* increase sk_wmem_alloc */
 989                         base += size;
 990                         len -= size;
 991                         i++;
 992                 }
 993                 offset = 0;
 994                 ++from;
 995         }
 996         return 0;
 997 }
 998
 999 /* Get packet from user space buffer */
1000 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1001                             void *msg_control, const struct iovec *iv,
1002                             size_t total_len, size_t count, int noblock)
1003 {
1004         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1005         struct sk_buff *skb;
1006         size_t len = total_len, align = NET_SKB_PAD;
1007         struct virtio_net_hdr gso = { 0 };
1008         int offset = 0;
1009         int copylen;
1010         bool zerocopy = false;
1011         int err;
1012
1013         if (!(tun->flags & TUN_NO_PI)) {
1014                 if ((len -= sizeof(pi)) > total_len)
1015                         return -EINVAL;
1016
1017                 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
1018                         return -EFAULT;
1019                 offset += sizeof(pi);
1020         }
1021
1022         if (tun->flags & TUN_VNET_HDR) {
1023                 if ((len -= tun->vnet_hdr_sz) > total_len)
1024                         return -EINVAL;
1025
1026                 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
1027                         return -EFAULT;
1028
1029                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1030                     gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
1031                         gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
1032
1033                 if (gso.hdr_len > len)
1034                         return -EINVAL;
1035                 offset += tun->vnet_hdr_sz;
1036         }
1037
1038         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
1039                 align += NET_IP_ALIGN;
1040                 if (unlikely(len < ETH_HLEN ||
1041                              (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
1042                         return -EINVAL;
1043         }
1044
1045         if (msg_control)
1046                 zerocopy = true;
1047
1048         if (zerocopy) {
1049                 /* Userspace may produce vectors with count greater than
1050                  * MAX_SKB_FRAGS, so we need to linearize parts of the skb
1051                  * to let the rest of data to be fit in the frags.
1052                  */
1053                 if (count > MAX_SKB_FRAGS) {
1054                         copylen = iov_length(iv, count - MAX_SKB_FRAGS);
1055                         if (copylen < offset)
1056                                 copylen = 0;
1057                         else
1058                                 copylen -= offset;
1059                 } else
1060                                 copylen = 0;
1061                 /* There are 256 bytes to be copied in skb, so there is enough
1062                  * room for skb expand head in case it is used.
1063                  * The rest of the buffer is mapped from userspace.
1064                  */
1065                 if (copylen < gso.hdr_len)
1066                         copylen = gso.hdr_len;
1067                 if (!copylen)
1068                         copylen = GOODCOPY_LEN;
1069         } else
1070                 copylen = len;
1071
1072         skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, noblock);
1073         if (IS_ERR(skb)) {
1074                 if (PTR_ERR(skb) != -EAGAIN)
1075                         tun->dev->stats.rx_dropped++;
1076                 return PTR_ERR(skb);
1077         }
1078
1079         if (zerocopy)
1080                 err = zerocopy_sg_from_iovec(skb, iv, offset, count);
1081         else
1082                 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
1083
1084         if (err) {
1085                 tun->dev->stats.rx_dropped++;
1086                 kfree_skb(skb);
1087                 return -EFAULT;
1088         }
1089
1090         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1091                 if (!skb_partial_csum_set(skb, gso.csum_start,
1092                                           gso.csum_offset)) {
1093                         tun->dev->stats.rx_frame_errors++;
1094                         kfree_skb(skb);
1095                         return -EINVAL;
1096                 }
1097         }
1098
1099         switch (tun->flags & TUN_TYPE_MASK) {
1100         case TUN_TUN_DEV:
1101                 if (tun->flags & TUN_NO_PI) {
1102                         switch (skb->data[0] & 0xf0) {
1103                         case 0x40:
1104                                 pi.proto = htons(ETH_P_IP);
1105                                 break;
1106                         case 0x60:
1107                                 pi.proto = htons(ETH_P_IPV6);
1108                                 break;
1109                         default:
1110                                 tun->dev->stats.rx_dropped++;
1111                                 kfree_skb(skb);
1112                                 return -EINVAL;
1113                         }
1114                 }
1115
1116                 skb_reset_mac_header(skb);
1117                 skb->protocol = pi.proto;
1118                 skb->dev = tun->dev;
1119                 break;
1120         case TUN_TAP_DEV:
1121                 skb->protocol = eth_type_trans(skb, tun->dev);
1122                 break;
1123         }
1124
1125         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1126                 pr_debug("GSO!\n");
1127                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1128                 case VIRTIO_NET_HDR_GSO_TCPV4:
1129                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1130                         break;
1131                 case VIRTIO_NET_HDR_GSO_TCPV6:
1132                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1133                         break;
1134                 case VIRTIO_NET_HDR_GSO_UDP:
1135                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1136                         break;
1137                 default:
1138                         tun->dev->stats.rx_frame_errors++;
1139                         kfree_skb(skb);
1140                         return -EINVAL;
1141                 }
1142
1143                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1144                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1145
1146                 skb_shinfo(skb)->gso_size = gso.gso_size;
1147                 if (skb_shinfo(skb)->gso_size == 0) {
1148                         tun->dev->stats.rx_frame_errors++;
1149                         kfree_skb(skb);
1150                         return -EINVAL;
1151                 }
1152
1153                 /* Header must be checked, and gso_segs computed. */
1154                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1155                 skb_shinfo(skb)->gso_segs = 0;
1156         }
1157
1158         /* copy skb_ubuf_info for callback when skb has no error */
1159         if (zerocopy) {
1160                 skb_shinfo(skb)->destructor_arg = msg_control;
1161                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1162         }
1163
1164         netif_rx_ni(skb);
1165
1166         tun->dev->stats.rx_packets++;
1167         tun->dev->stats.rx_bytes += len;
1168
1169         tun_flow_update(tun, skb, tfile->queue_index);
1170         return total_len;
1171 }
1172
1173 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
1174                               unsigned long count, loff_t pos)
1175 {
1176         struct file *file = iocb->ki_filp;
1177         struct tun_struct *tun = tun_get(file);
1178         struct tun_file *tfile = file->private_data;
1179         ssize_t result;
1180
1181         if (!tun)
1182                 return -EBADFD;
1183
1184         tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
1185
1186         result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count),
1187                               count, file->f_flags & O_NONBLOCK);
1188
1189         tun_put(tun);
1190         return result;
1191 }
1192
1193 /* Put packet to the user space buffer */
1194 static ssize_t tun_put_user(struct tun_struct *tun,
1195                             struct tun_file *tfile,
1196                             struct sk_buff *skb,
1197                             const struct iovec *iv, int len)
1198 {
1199         struct tun_pi pi = { 0, skb->protocol };
1200         ssize_t total = 0;
1201
1202         if (!(tun->flags & TUN_NO_PI)) {
1203                 if ((len -= sizeof(pi)) < 0)
1204                         return -EINVAL;
1205
1206                 if (len < skb->len) {
1207                         /* Packet will be striped */
1208                         pi.flags |= TUN_PKT_STRIP;
1209                 }
1210
1211                 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
1212                         return -EFAULT;
1213                 total += sizeof(pi);
1214         }
1215
1216         if (tun->flags & TUN_VNET_HDR) {
1217                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1218                 if ((len -= tun->vnet_hdr_sz) < 0)
1219                         return -EINVAL;
1220
1221                 if (skb_is_gso(skb)) {
1222                         struct skb_shared_info *sinfo = skb_shinfo(skb);
1223
1224                         /* This is a hint as to how much should be linear. */
1225                         gso.hdr_len = skb_headlen(skb);
1226                         gso.gso_size = sinfo->gso_size;
1227                         if (sinfo->gso_type & SKB_GSO_TCPV4)
1228                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1229                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
1230                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1231                         else if (sinfo->gso_type & SKB_GSO_UDP)
1232                                 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1233                         else {
1234                                 pr_err("unexpected GSO type: "
1235                                        "0x%x, gso_size %d, hdr_len %d\n",
1236                                        sinfo->gso_type, gso.gso_size,
1237                                        gso.hdr_len);
1238                                 print_hex_dump(KERN_ERR, "tun: ",
1239                                                DUMP_PREFIX_NONE,
1240                                                16, 1, skb->head,
1241                                                min((int)gso.hdr_len, 64), true);
1242                                 WARN_ON_ONCE(1);
1243                                 return -EINVAL;
1244                         }
1245                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1246                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1247                 } else
1248                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1249
1250                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1251                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1252                         gso.csum_start = skb_checksum_start_offset(skb);
1253                         gso.csum_offset = skb->csum_offset;
1254                 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1255                         gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1256                 } /* else everything is zero */
1257
1258                 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
1259                                                sizeof(gso))))
1260                         return -EFAULT;
1261                 total += tun->vnet_hdr_sz;
1262         }
1263
1264         len = min_t(int, skb->len, len);
1265
1266         skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
1267         total += skb->len;
1268
1269         tun->dev->stats.tx_packets++;
1270         tun->dev->stats.tx_bytes += len;
1271
1272         return total;
1273 }
1274
1275 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1276                            struct kiocb *iocb, const struct iovec *iv,
1277                            ssize_t len, int noblock)
1278 {
1279         DECLARE_WAITQUEUE(wait, current);
1280         struct sk_buff *skb;
1281         ssize_t ret = 0;
1282
1283         tun_debug(KERN_INFO, tun, "tun_do_read\n");
1284
1285         if (unlikely(!noblock))
1286                 add_wait_queue(&tfile->wq.wait, &wait);
1287         while (len) {
1288                 current->state = TASK_INTERRUPTIBLE;
1289
1290                 /* Read frames from the queue */
1291                 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) {
1292                         if (noblock) {
1293                                 ret = -EAGAIN;
1294                                 break;
1295                         }
1296                         if (signal_pending(current)) {
1297                                 ret = -ERESTARTSYS;
1298                                 break;
1299                         }
1300                         if (tun->dev->reg_state != NETREG_REGISTERED) {
1301                                 ret = -EIO;
1302                                 break;
1303                         }
1304
1305                         /* Nothing to read, let's sleep */
1306                         schedule();
1307                         continue;
1308                 }
1309
1310                 ret = tun_put_user(tun, tfile, skb, iv, len);
1311                 kfree_skb(skb);
1312                 break;
1313         }
1314
1315         current->state = TASK_RUNNING;
1316         if (unlikely(!noblock))
1317                 remove_wait_queue(&tfile->wq.wait, &wait);
1318
1319         return ret;
1320 }
1321
1322 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1323                             unsigned long count, loff_t pos)
1324 {
1325         struct file *file = iocb->ki_filp;
1326         struct tun_file *tfile = file->private_data;
1327         struct tun_struct *tun = __tun_get(tfile);
1328         ssize_t len, ret;
1329
1330         if (!tun)
1331                 return -EBADFD;
1332         len = iov_length(iv, count);
1333         if (len < 0) {
1334                 ret = -EINVAL;
1335                 goto out;
1336         }
1337
1338         ret = tun_do_read(tun, tfile, iocb, iv, len,
1339                           file->f_flags & O_NONBLOCK);
1340         ret = min_t(ssize_t, ret, len);
1341 out:
1342         tun_put(tun);
1343         return ret;
1344 }
1345
1346 static void tun_free_netdev(struct net_device *dev)
1347 {
1348         struct tun_struct *tun = netdev_priv(dev);
1349
1350         tun_flow_uninit(tun);
1351         free_netdev(dev);
1352 }
1353
1354 static void tun_setup(struct net_device *dev)
1355 {
1356         struct tun_struct *tun = netdev_priv(dev);
1357
1358         tun->owner = INVALID_UID;
1359         tun->group = INVALID_GID;
1360
1361         dev->ethtool_ops = &tun_ethtool_ops;
1362         dev->destructor = tun_free_netdev;
1363 }
1364
1365 /* Trivial set of netlink ops to allow deleting tun or tap
1366  * device with netlink.
1367  */
1368 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1369 {
1370         return -EINVAL;
1371 }
1372
1373 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1374         .kind           = DRV_NAME,
1375         .priv_size      = sizeof(struct tun_struct),
1376         .setup          = tun_setup,
1377         .validate       = tun_validate,
1378 };
1379
1380 static void tun_sock_write_space(struct sock *sk)
1381 {
1382         struct tun_file *tfile;
1383         wait_queue_head_t *wqueue;
1384
1385         if (!sock_writeable(sk))
1386                 return;
1387
1388         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1389                 return;
1390
1391         wqueue = sk_sleep(sk);
1392         if (wqueue && waitqueue_active(wqueue))
1393                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1394                                                 POLLWRNORM | POLLWRBAND);
1395
1396         tfile = container_of(sk, struct tun_file, sk);
1397         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1398 }
1399
1400 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1401                        struct msghdr *m, size_t total_len)
1402 {
1403         int ret;
1404         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1405         struct tun_struct *tun = __tun_get(tfile);
1406
1407         if (!tun)
1408                 return -EBADFD;
1409         ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len,
1410                            m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1411         tun_put(tun);
1412         return ret;
1413 }
1414
1415
1416 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1417                        struct msghdr *m, size_t total_len,
1418                        int flags)
1419 {
1420         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1421         struct tun_struct *tun = __tun_get(tfile);
1422         int ret;
1423
1424         if (!tun)
1425                 return -EBADFD;
1426
1427         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1428                 return -EINVAL;
1429         ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len,
1430                           flags & MSG_DONTWAIT);
1431         if (ret > total_len) {
1432                 m->msg_flags |= MSG_TRUNC;
1433                 ret = flags & MSG_TRUNC ? ret : total_len;
1434         }
1435         tun_put(tun);
1436         return ret;
1437 }
1438
1439 static int tun_release(struct socket *sock)
1440 {
1441         if (sock->sk)
1442                 sock_put(sock->sk);
1443         return 0;
1444 }
1445
1446 /* Ops structure to mimic raw sockets with tun */
1447 static const struct proto_ops tun_socket_ops = {
1448         .sendmsg = tun_sendmsg,
1449         .recvmsg = tun_recvmsg,
1450         .release = tun_release,
1451 };
1452
1453 static struct proto tun_proto = {
1454         .name           = "tun",
1455         .owner          = THIS_MODULE,
1456         .obj_size       = sizeof(struct tun_file),
1457 };
1458
1459 static int tun_flags(struct tun_struct *tun)
1460 {
1461         int flags = 0;
1462
1463         if (tun->flags & TUN_TUN_DEV)
1464                 flags |= IFF_TUN;
1465         else
1466                 flags |= IFF_TAP;
1467
1468         if (tun->flags & TUN_NO_PI)
1469                 flags |= IFF_NO_PI;
1470
1471         /* This flag has no real effect.  We track the value for backwards
1472          * compatibility.
1473          */
1474         if (tun->flags & TUN_ONE_QUEUE)
1475                 flags |= IFF_ONE_QUEUE;
1476
1477         if (tun->flags & TUN_VNET_HDR)
1478                 flags |= IFF_VNET_HDR;
1479
1480         if (tun->flags & TUN_TAP_MQ)
1481                 flags |= IFF_MULTI_QUEUE;
1482
1483         return flags;
1484 }
1485
1486 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1487                               char *buf)
1488 {
1489         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1490         return sprintf(buf, "0x%x\n", tun_flags(tun));
1491 }
1492
1493 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1494                               char *buf)
1495 {
1496         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1497         return uid_valid(tun->owner)?
1498                 sprintf(buf, "%u\n",
1499                         from_kuid_munged(current_user_ns(), tun->owner)):
1500                 sprintf(buf, "-1\n");
1501 }
1502
1503 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1504                               char *buf)
1505 {
1506         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1507         return gid_valid(tun->group) ?
1508                 sprintf(buf, "%u\n",
1509                         from_kgid_munged(current_user_ns(), tun->group)):
1510                 sprintf(buf, "-1\n");
1511 }
1512
1513 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1514 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1515 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1516
1517 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1518 {
1519         struct tun_struct *tun;
1520         struct tun_file *tfile = file->private_data;
1521         struct net_device *dev;
1522         int err;
1523
1524         dev = __dev_get_by_name(net, ifr->ifr_name);
1525         if (dev) {
1526                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1527                         return -EBUSY;
1528                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1529                         tun = netdev_priv(dev);
1530                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1531                         tun = netdev_priv(dev);
1532                 else
1533                         return -EINVAL;
1534
1535                 if (tun_not_capable(tun))
1536                         return -EPERM;
1537                 err = security_tun_dev_attach(tfile->socket.sk);
1538                 if (err < 0)
1539                         return err;
1540
1541                 err = tun_attach(tun, file);
1542                 if (err < 0)
1543                         return err;
1544         }
1545         else {
1546                 char *name;
1547                 unsigned long flags = 0;
1548
1549                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1550                         return -EPERM;
1551                 err = security_tun_dev_create();
1552                 if (err < 0)
1553                         return err;
1554
1555                 /* Set dev type */
1556                 if (ifr->ifr_flags & IFF_TUN) {
1557                         /* TUN device */
1558                         flags |= TUN_TUN_DEV;
1559                         name = "tun%d";
1560                 } else if (ifr->ifr_flags & IFF_TAP) {
1561                         /* TAP device */
1562                         flags |= TUN_TAP_DEV;
1563                         name = "tap%d";
1564                 } else
1565                         return -EINVAL;
1566
1567                 if (*ifr->ifr_name)
1568                         name = ifr->ifr_name;
1569
1570                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1571                                        tun_setup,
1572                                        MAX_TAP_QUEUES, MAX_TAP_QUEUES);
1573                 if (!dev)
1574                         return -ENOMEM;
1575
1576                 dev_net_set(dev, net);
1577                 dev->rtnl_link_ops = &tun_link_ops;
1578
1579                 tun = netdev_priv(dev);
1580                 tun->dev = dev;
1581                 tun->flags = flags;
1582                 tun->txflt.count = 0;
1583                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1584
1585                 tun->filter_attached = false;
1586                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1587
1588                 spin_lock_init(&tun->lock);
1589
1590                 security_tun_dev_post_create(&tfile->sk);
1591
1592                 tun_net_init(dev);
1593
1594                 err = tun_flow_init(tun);
1595                 if (err < 0)
1596                         goto err_free_dev;
1597
1598                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1599                         TUN_USER_FEATURES;
1600                 dev->features = dev->hw_features;
1601
1602                 err = tun_attach(tun, file);
1603                 if (err < 0)
1604                         goto err_free_dev;
1605
1606                 err = register_netdevice(tun->dev);
1607                 if (err < 0)
1608                         goto err_free_dev;
1609
1610                 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1611                     device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1612                     device_create_file(&tun->dev->dev, &dev_attr_group))
1613                         pr_err("Failed to create tun sysfs files\n");
1614
1615                 netif_carrier_on(tun->dev);
1616         }
1617
1618         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1619
1620         if (ifr->ifr_flags & IFF_NO_PI)
1621                 tun->flags |= TUN_NO_PI;
1622         else
1623                 tun->flags &= ~TUN_NO_PI;
1624
1625         /* This flag has no real effect.  We track the value for backwards
1626          * compatibility.
1627          */
1628         if (ifr->ifr_flags & IFF_ONE_QUEUE)
1629                 tun->flags |= TUN_ONE_QUEUE;
1630         else
1631                 tun->flags &= ~TUN_ONE_QUEUE;
1632
1633         if (ifr->ifr_flags & IFF_VNET_HDR)
1634                 tun->flags |= TUN_VNET_HDR;
1635         else
1636                 tun->flags &= ~TUN_VNET_HDR;
1637
1638         if (ifr->ifr_flags & IFF_MULTI_QUEUE)
1639                 tun->flags |= TUN_TAP_MQ;
1640         else
1641                 tun->flags &= ~TUN_TAP_MQ;
1642
1643         /* Make sure persistent devices do not get stuck in
1644          * xoff state.
1645          */
1646         if (netif_running(tun->dev))
1647                 netif_tx_wake_all_queues(tun->dev);
1648
1649         strcpy(ifr->ifr_name, tun->dev->name);
1650         return 0;
1651
1652  err_free_dev:
1653         free_netdev(dev);
1654         return err;
1655 }
1656
1657 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1658                        struct ifreq *ifr)
1659 {
1660         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1661
1662         strcpy(ifr->ifr_name, tun->dev->name);
1663
1664         ifr->ifr_flags = tun_flags(tun);
1665
1666 }
1667
1668 /* This is like a cut-down ethtool ops, except done via tun fd so no
1669  * privs required. */
1670 static int set_offload(struct tun_struct *tun, unsigned long arg)
1671 {
1672         netdev_features_t features = 0;
1673
1674         if (arg & TUN_F_CSUM) {
1675                 features |= NETIF_F_HW_CSUM;
1676                 arg &= ~TUN_F_CSUM;
1677
1678                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1679                         if (arg & TUN_F_TSO_ECN) {
1680                                 features |= NETIF_F_TSO_ECN;
1681                                 arg &= ~TUN_F_TSO_ECN;
1682                         }
1683                         if (arg & TUN_F_TSO4)
1684                                 features |= NETIF_F_TSO;
1685                         if (arg & TUN_F_TSO6)
1686                                 features |= NETIF_F_TSO6;
1687                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1688                 }
1689
1690                 if (arg & TUN_F_UFO) {
1691                         features |= NETIF_F_UFO;
1692                         arg &= ~TUN_F_UFO;
1693                 }
1694         }
1695
1696         /* This gives the user a way to test for new features in future by
1697          * trying to set them. */
1698         if (arg)
1699                 return -EINVAL;
1700
1701         tun->set_features = features;
1702         netdev_update_features(tun->dev);
1703
1704         return 0;
1705 }
1706
1707 static void tun_detach_filter(struct tun_struct *tun, int n)
1708 {
1709         int i;
1710         struct tun_file *tfile;
1711
1712         for (i = 0; i < n; i++) {
1713                 tfile = rcu_dereference_protected(tun->tfiles[i],
1714                                                   lockdep_rtnl_is_held());
1715                 sk_detach_filter(tfile->socket.sk);
1716         }
1717
1718         tun->filter_attached = false;
1719 }
1720
1721 static int tun_attach_filter(struct tun_struct *tun)
1722 {
1723         int i, ret = 0;
1724         struct tun_file *tfile;
1725
1726         for (i = 0; i < tun->numqueues; i++) {
1727                 tfile = rcu_dereference_protected(tun->tfiles[i],
1728                                                   lockdep_rtnl_is_held());
1729                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1730                 if (ret) {
1731                         tun_detach_filter(tun, i);
1732                         return ret;
1733                 }
1734         }
1735
1736         tun->filter_attached = true;
1737         return ret;
1738 }
1739
1740 static void tun_set_sndbuf(struct tun_struct *tun)
1741 {
1742         struct tun_file *tfile;
1743         int i;
1744
1745         for (i = 0; i < tun->numqueues; i++) {
1746                 tfile = rcu_dereference_protected(tun->tfiles[i],
1747                                                 lockdep_rtnl_is_held());
1748                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1749         }
1750 }
1751
1752 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1753 {
1754         struct tun_file *tfile = file->private_data;
1755         struct tun_struct *tun;
1756         struct net_device *dev;
1757         int ret = 0;
1758
1759         rtnl_lock();
1760
1761         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1762                 dev = __dev_get_by_name(tfile->net, ifr->ifr_name);
1763                 if (!dev) {
1764                         ret = -EINVAL;
1765                         goto unlock;
1766                 }
1767
1768                 tun = netdev_priv(dev);
1769                 if (dev->netdev_ops != &tap_netdev_ops &&
1770                         dev->netdev_ops != &tun_netdev_ops)
1771                         ret = -EINVAL;
1772                 else if (tun_not_capable(tun))
1773                         ret = -EPERM;
1774                 else
1775                         ret = tun_attach(tun, file);
1776         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE)
1777                 __tun_detach(tfile, false);
1778         else
1779                 ret = -EINVAL;
1780
1781 unlock:
1782         rtnl_unlock();
1783         return ret;
1784 }
1785
1786 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1787                             unsigned long arg, int ifreq_len)
1788 {
1789         struct tun_file *tfile = file->private_data;
1790         struct tun_struct *tun;
1791         void __user* argp = (void __user*)arg;
1792         struct ifreq ifr;
1793         kuid_t owner;
1794         kgid_t group;
1795         int sndbuf;
1796         int vnet_hdr_sz;
1797         int ret;
1798
1799         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1800                 if (copy_from_user(&ifr, argp, ifreq_len))
1801                         return -EFAULT;
1802         } else {
1803                 memset(&ifr, 0, sizeof(ifr));
1804         }
1805         if (cmd == TUNGETFEATURES) {
1806                 /* Currently this just means: "what IFF flags are valid?".
1807                  * This is needed because we never checked for invalid flags on
1808                  * TUNSETIFF. */
1809                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1810                                 IFF_VNET_HDR | IFF_MULTI_QUEUE,
1811                                 (unsigned int __user*)argp);
1812         } else if (cmd == TUNSETQUEUE)
1813                 return tun_set_queue(file, &ifr);
1814
1815         ret = 0;
1816         rtnl_lock();
1817
1818         tun = __tun_get(tfile);
1819         if (cmd == TUNSETIFF && !tun) {
1820                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1821
1822                 ret = tun_set_iff(tfile->net, file, &ifr);
1823
1824                 if (ret)
1825                         goto unlock;
1826
1827                 if (copy_to_user(argp, &ifr, ifreq_len))
1828                         ret = -EFAULT;
1829                 goto unlock;
1830         }
1831
1832         ret = -EBADFD;
1833         if (!tun)
1834                 goto unlock;
1835
1836         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1837
1838         ret = 0;
1839         switch (cmd) {
1840         case TUNGETIFF:
1841                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1842
1843                 if (copy_to_user(argp, &ifr, ifreq_len))
1844                         ret = -EFAULT;
1845                 break;
1846
1847         case TUNSETNOCSUM:
1848                 /* Disable/Enable checksum */
1849
1850                 /* [unimplemented] */
1851                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1852                           arg ? "disabled" : "enabled");
1853                 break;
1854
1855         case TUNSETPERSIST:
1856                 /* Disable/Enable persist mode. Keep an extra reference to the
1857                  * module to prevent the module being unprobed.
1858                  */
1859                 if (arg) {
1860                         tun->flags |= TUN_PERSIST;
1861                         __module_get(THIS_MODULE);
1862                 } else {
1863                         tun->flags &= ~TUN_PERSIST;
1864                         module_put(THIS_MODULE);
1865                 }
1866
1867                 tun_debug(KERN_INFO, tun, "persist %s\n",
1868                           arg ? "enabled" : "disabled");
1869                 break;
1870
1871         case TUNSETOWNER:
1872                 /* Set owner of the device */
1873                 owner = make_kuid(current_user_ns(), arg);
1874                 if (!uid_valid(owner)) {
1875                         ret = -EINVAL;
1876                         break;
1877                 }
1878                 tun->owner = owner;
1879                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
1880                           from_kuid(&init_user_ns, tun->owner));
1881                 break;
1882
1883         case TUNSETGROUP:
1884                 /* Set group of the device */
1885                 group = make_kgid(current_user_ns(), arg);
1886                 if (!gid_valid(group)) {
1887                         ret = -EINVAL;
1888                         break;
1889                 }
1890                 tun->group = group;
1891                 tun_debug(KERN_INFO, tun, "group set to %u\n",
1892                           from_kgid(&init_user_ns, tun->group));
1893                 break;
1894
1895         case TUNSETLINK:
1896                 /* Only allow setting the type when the interface is down */
1897                 if (tun->dev->flags & IFF_UP) {
1898                         tun_debug(KERN_INFO, tun,
1899                                   "Linktype set failed because interface is up\n");
1900                         ret = -EBUSY;
1901                 } else {
1902                         tun->dev->type = (int) arg;
1903                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1904                                   tun->dev->type);
1905                         ret = 0;
1906                 }
1907                 break;
1908
1909 #ifdef TUN_DEBUG
1910         case TUNSETDEBUG:
1911                 tun->debug = arg;
1912                 break;
1913 #endif
1914         case TUNSETOFFLOAD:
1915                 ret = set_offload(tun, arg);
1916                 break;
1917
1918         case TUNSETTXFILTER:
1919                 /* Can be set only for TAPs */
1920                 ret = -EINVAL;
1921                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1922                         break;
1923                 ret = update_filter(&tun->txflt, (void __user *)arg);
1924                 break;
1925
1926         case SIOCGIFHWADDR:
1927                 /* Get hw address */
1928                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1929                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1930                 if (copy_to_user(argp, &ifr, ifreq_len))
1931                         ret = -EFAULT;
1932                 break;
1933
1934         case SIOCSIFHWADDR:
1935                 /* Set hw address */
1936                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1937                           ifr.ifr_hwaddr.sa_data);
1938
1939                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1940                 break;
1941
1942         case TUNGETSNDBUF:
1943                 sndbuf = tfile->socket.sk->sk_sndbuf;
1944                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1945                         ret = -EFAULT;
1946                 break;
1947
1948         case TUNSETSNDBUF:
1949                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1950                         ret = -EFAULT;
1951                         break;
1952                 }
1953
1954                 tun->sndbuf = sndbuf;
1955                 tun_set_sndbuf(tun);
1956                 break;
1957
1958         case TUNGETVNETHDRSZ:
1959                 vnet_hdr_sz = tun->vnet_hdr_sz;
1960                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
1961                         ret = -EFAULT;
1962                 break;
1963
1964         case TUNSETVNETHDRSZ:
1965                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
1966                         ret = -EFAULT;
1967                         break;
1968                 }
1969                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
1970                         ret = -EINVAL;
1971                         break;
1972                 }
1973
1974                 tun->vnet_hdr_sz = vnet_hdr_sz;
1975                 break;
1976
1977         case TUNATTACHFILTER:
1978                 /* Can be set only for TAPs */
1979                 ret = -EINVAL;
1980                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1981                         break;
1982                 ret = -EFAULT;
1983                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
1984                         break;
1985
1986                 ret = tun_attach_filter(tun);
1987                 break;
1988
1989         case TUNDETACHFILTER:
1990                 /* Can be set only for TAPs */
1991                 ret = -EINVAL;
1992                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1993                         break;
1994                 ret = 0;
1995                 tun_detach_filter(tun, tun->numqueues);
1996                 break;
1997
1998         default:
1999                 ret = -EINVAL;
2000                 break;
2001         }
2002
2003 unlock:
2004         rtnl_unlock();
2005         if (tun)
2006                 tun_put(tun);
2007         return ret;
2008 }
2009
2010 static long tun_chr_ioctl(struct file *file,
2011                           unsigned int cmd, unsigned long arg)
2012 {
2013         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2014 }
2015
2016 #ifdef CONFIG_COMPAT
2017 static long tun_chr_compat_ioctl(struct file *file,
2018                          unsigned int cmd, unsigned long arg)
2019 {
2020         switch (cmd) {
2021         case TUNSETIFF:
2022         case TUNGETIFF:
2023         case TUNSETTXFILTER:
2024         case TUNGETSNDBUF:
2025         case TUNSETSNDBUF:
2026         case SIOCGIFHWADDR:
2027         case SIOCSIFHWADDR:
2028                 arg = (unsigned long)compat_ptr(arg);
2029                 break;
2030         default:
2031                 arg = (compat_ulong_t)arg;
2032                 break;
2033         }
2034
2035         /*
2036          * compat_ifreq is shorter than ifreq, so we must not access beyond
2037          * the end of that structure. All fields that are used in this
2038          * driver are compatible though, we don't need to convert the
2039          * contents.
2040          */
2041         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2042 }
2043 #endif /* CONFIG_COMPAT */
2044
2045 static int tun_chr_fasync(int fd, struct file *file, int on)
2046 {
2047         struct tun_file *tfile = file->private_data;
2048         int ret;
2049
2050         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2051                 goto out;
2052
2053         if (on) {
2054                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2055                 if (ret)
2056                         goto out;
2057                 tfile->flags |= TUN_FASYNC;
2058         } else
2059                 tfile->flags &= ~TUN_FASYNC;
2060         ret = 0;
2061 out:
2062         return ret;
2063 }
2064
2065 static int tun_chr_open(struct inode *inode, struct file * file)
2066 {
2067         struct tun_file *tfile;
2068
2069         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2070
2071         tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
2072                                             &tun_proto);
2073         if (!tfile)
2074                 return -ENOMEM;
2075         rcu_assign_pointer(tfile->tun, NULL);
2076         tfile->net = get_net(current->nsproxy->net_ns);
2077         tfile->flags = 0;
2078
2079         rcu_assign_pointer(tfile->socket.wq, &tfile->wq);
2080         init_waitqueue_head(&tfile->wq.wait);
2081
2082         tfile->socket.file = file;
2083         tfile->socket.ops = &tun_socket_ops;
2084
2085         sock_init_data(&tfile->socket, &tfile->sk);
2086         sk_change_net(&tfile->sk, tfile->net);
2087
2088         tfile->sk.sk_write_space = tun_sock_write_space;
2089         tfile->sk.sk_sndbuf = INT_MAX;
2090
2091         file->private_data = tfile;
2092         set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
2093
2094         return 0;
2095 }
2096
2097 static int tun_chr_close(struct inode *inode, struct file *file)
2098 {
2099         struct tun_file *tfile = file->private_data;
2100         struct net *net = tfile->net;
2101
2102         tun_detach(tfile, true);
2103         put_net(net);
2104
2105         return 0;
2106 }
2107
2108 static const struct file_operations tun_fops = {
2109         .owner  = THIS_MODULE,
2110         .llseek = no_llseek,
2111         .read  = do_sync_read,
2112         .aio_read  = tun_chr_aio_read,
2113         .write = do_sync_write,
2114         .aio_write = tun_chr_aio_write,
2115         .poll   = tun_chr_poll,
2116         .unlocked_ioctl = tun_chr_ioctl,
2117 #ifdef CONFIG_COMPAT
2118         .compat_ioctl = tun_chr_compat_ioctl,
2119 #endif
2120         .open   = tun_chr_open,
2121         .release = tun_chr_close,
2122         .fasync = tun_chr_fasync
2123 };
2124
2125 static struct miscdevice tun_miscdev = {
2126         .minor = TUN_MINOR,
2127         .name = "tun",
2128         .nodename = "net/tun",
2129         .fops = &tun_fops,
2130 };
2131
2132 /* ethtool interface */
2133
2134 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2135 {
2136         cmd->supported          = 0;
2137         cmd->advertising        = 0;
2138         ethtool_cmd_speed_set(cmd, SPEED_10);
2139         cmd->duplex             = DUPLEX_FULL;
2140         cmd->port               = PORT_TP;
2141         cmd->phy_address        = 0;
2142         cmd->transceiver        = XCVR_INTERNAL;
2143         cmd->autoneg            = AUTONEG_DISABLE;
2144         cmd->maxtxpkt           = 0;
2145         cmd->maxrxpkt           = 0;
2146         return 0;
2147 }
2148
2149 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2150 {
2151         struct tun_struct *tun = netdev_priv(dev);
2152
2153         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2154         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2155
2156         switch (tun->flags & TUN_TYPE_MASK) {
2157         case TUN_TUN_DEV:
2158                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2159                 break;
2160         case TUN_TAP_DEV:
2161                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2162                 break;
2163         }
2164 }
2165
2166 static u32 tun_get_msglevel(struct net_device *dev)
2167 {
2168 #ifdef TUN_DEBUG
2169         struct tun_struct *tun = netdev_priv(dev);
2170         return tun->debug;
2171 #else
2172         return -EOPNOTSUPP;
2173 #endif
2174 }
2175
2176 static void tun_set_msglevel(struct net_device *dev, u32 value)
2177 {
2178 #ifdef TUN_DEBUG
2179         struct tun_struct *tun = netdev_priv(dev);
2180         tun->debug = value;
2181 #endif
2182 }
2183
2184 static const struct ethtool_ops tun_ethtool_ops = {
2185         .get_settings   = tun_get_settings,
2186         .get_drvinfo    = tun_get_drvinfo,
2187         .get_msglevel   = tun_get_msglevel,
2188         .set_msglevel   = tun_set_msglevel,
2189         .get_link       = ethtool_op_get_link,
2190 };
2191
2192
2193 static int __init tun_init(void)
2194 {
2195         int ret = 0;
2196
2197         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2198         pr_info("%s\n", DRV_COPYRIGHT);
2199
2200         ret = rtnl_link_register(&tun_link_ops);
2201         if (ret) {
2202                 pr_err("Can't register link_ops\n");
2203                 goto err_linkops;
2204         }
2205
2206         ret = misc_register(&tun_miscdev);
2207         if (ret) {
2208                 pr_err("Can't register misc device %d\n", TUN_MINOR);
2209                 goto err_misc;
2210         }
2211         return  0;
2212 err_misc:
2213         rtnl_link_unregister(&tun_link_ops);
2214 err_linkops:
2215         return ret;
2216 }
2217
2218 static void tun_cleanup(void)
2219 {
2220         misc_deregister(&tun_miscdev);
2221         rtnl_link_unregister(&tun_link_ops);
2222 }
2223
2224 /* Get an underlying socket object from tun file.  Returns error unless file is
2225  * attached to a device.  The returned object works like a packet socket, it
2226  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2227  * holding a reference to the file for as long as the socket is in use. */
2228 struct socket *tun_get_socket(struct file *file)
2229 {
2230         struct tun_file *tfile;
2231         if (file->f_op != &tun_fops)
2232                 return ERR_PTR(-EINVAL);
2233         tfile = file->private_data;
2234         if (!tfile)
2235                 return ERR_PTR(-EBADFD);
2236         return &tfile->socket;
2237 }
2238 EXPORT_SYMBOL_GPL(tun_get_socket);
2239
2240 module_init(tun_init);
2241 module_exit(tun_cleanup);
2242 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2243 MODULE_AUTHOR(DRV_COPYRIGHT);
2244 MODULE_LICENSE("GPL");
2245 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2246 MODULE_ALIAS("devname:net/tun");