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 hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 184         struct timer_list flow_gc_timer;
 185         unsigned long ageing_time;
 186         unsigned int numdisabled;
 187         struct list_head disabled;
 188 };
 189
 190 static inline u32 tun_hashfn(u32 rxhash)
 191 {
 192         return rxhash & 0x3ff;
 193 }
 194
 195 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 196 {
 197         struct tun_flow_entry *e;
 198         struct hlist_node *n;
 199
 200         hlist_for_each_entry_rcu(e, n, head, hash_link) {
 201                 if (e->rxhash == rxhash)
 202                         return e;
 203         }
 204         return NULL;
 205 }
 206
 207 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 208                                               struct hlist_head *head,
 209                                               u32 rxhash, u16 queue_index)
 210 {
 211         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 212
 213         if (e) {
 214                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 215                           rxhash, queue_index);
 216                 e->updated = jiffies;
 217                 e->rxhash = rxhash;
 218                 e->queue_index = queue_index;
 219                 e->tun = tun;
 220                 hlist_add_head_rcu(&e->hash_link, head);
 221         }
 222         return e;
 223 }
 224
 225 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 226 {
 227         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 228                   e->rxhash, e->queue_index);
 229         hlist_del_rcu(&e->hash_link);
 230         kfree_rcu(e, rcu);
 231 }
 232
 233 static void tun_flow_flush(struct tun_struct *tun)
 234 {
 235         int i;
 236
 237         spin_lock_bh(&tun->lock);
 238         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 239                 struct tun_flow_entry *e;
 240                 struct hlist_node *h, *n;
 241
 242                 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link)
 243                         tun_flow_delete(tun, e);
 244         }
 245         spin_unlock_bh(&tun->lock);
 246 }
 247
 248 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 249 {
 250         int i;
 251
 252         spin_lock_bh(&tun->lock);
 253         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 254                 struct tun_flow_entry *e;
 255                 struct hlist_node *h, *n;
 256
 257                 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link) {
 258                         if (e->queue_index == queue_index)
 259                                 tun_flow_delete(tun, e);
 260                 }
 261         }
 262         spin_unlock_bh(&tun->lock);
 263 }
 264
 265 static void tun_flow_cleanup(unsigned long data)
 266 {
 267         struct tun_struct *tun = (struct tun_struct *)data;
 268         unsigned long delay = tun->ageing_time;
 269         unsigned long next_timer = jiffies + delay;
 270         unsigned long count = 0;
 271         int i;
 272
 273         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 274
 275         spin_lock_bh(&tun->lock);
 276         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 277                 struct tun_flow_entry *e;
 278                 struct hlist_node *h, *n;
 279
 280                 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link) {
 281                         unsigned long this_timer;
 282                         count++;
 283                         this_timer = e->updated + delay;
 284                         if (time_before_eq(this_timer, jiffies))
 285                                 tun_flow_delete(tun, e);
 286                         else if (time_before(this_timer, next_timer))
 287                                 next_timer = this_timer;
 288                 }
 289         }
 290
 291         if (count)
 292                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 293         spin_unlock_bh(&tun->lock);
 294 }
 295
 296 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 297                             u16 queue_index)
 298 {
 299         struct hlist_head *head;
 300         struct tun_flow_entry *e;
 301         unsigned long delay = tun->ageing_time;
 302
 303         if (!rxhash)
 304                 return;
 305         else
 306                 head = &tun->flows[tun_hashfn(rxhash)];
 307
 308         rcu_read_lock();
 309
 310         if (tun->numqueues == 1)
 311                 goto unlock;
 312
 313         e = tun_flow_find(head, rxhash);
 314         if (likely(e)) {
 315                 /* TODO: keep queueing to old queue until it's empty? */
 316                 e->queue_index = queue_index;
 317                 e->updated = jiffies;
 318         } else {
 319                 spin_lock_bh(&tun->lock);
 320                 if (!tun_flow_find(head, rxhash))
 321                         tun_flow_create(tun, head, rxhash, queue_index);
 322
 323                 if (!timer_pending(&tun->flow_gc_timer))
 324                         mod_timer(&tun->flow_gc_timer,
 325                                   round_jiffies_up(jiffies + delay));
 326                 spin_unlock_bh(&tun->lock);
 327         }
 328
 329 unlock:
 330         rcu_read_unlock();
 331 }
 332
 333 /* We try to identify a flow through its rxhash first. The reason that
 334  * we do not check rxq no. is becuase some cards(e.g 82599), chooses
 335  * the rxq based on the txq where the last packet of the flow comes. As
 336  * the userspace application move between processors, we may get a
 337  * different rxq no. here. If we could not get rxhash, then we would
 338  * hope the rxq no. may help here.
 339  */
 340 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb)
 341 {
 342         struct tun_struct *tun = netdev_priv(dev);
 343         struct tun_flow_entry *e;
 344         u32 txq = 0;
 345         u32 numqueues = 0;
 346
 347         rcu_read_lock();
 348         numqueues = tun->numqueues;
 349
 350         txq = skb_get_rxhash(skb);
 351         if (txq) {
 352                 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 353                 if (e)
 354                         txq = e->queue_index;
 355                 else
 356                         /* use multiply and shift instead of expensive divide */
 357                         txq = ((u64)txq * numqueues) >> 32;
 358         } else if (likely(skb_rx_queue_recorded(skb))) {
 359                 txq = skb_get_rx_queue(skb);
 360                 while (unlikely(txq >= numqueues))
 361                         txq -= numqueues;
 362         }
 363
 364         rcu_read_unlock();
 365         return txq;
 366 }
 367
 368 static inline bool tun_not_capable(struct tun_struct *tun)
 369 {
 370         const struct cred *cred = current_cred();
 371         struct net *net = dev_net(tun->dev);
 372
 373         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 374                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 375                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 376 }
 377
 378 static void tun_set_real_num_queues(struct tun_struct *tun)
 379 {
 380         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 381         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 382 }
 383
 384 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 385 {
 386         tfile->detached = tun;
 387         list_add_tail(&tfile->next, &tun->disabled);
 388         ++tun->numdisabled;
 389 }
 390
 391 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 392 {
 393         struct tun_struct *tun = tfile->detached;
 394
 395         tfile->detached = NULL;
 396         list_del_init(&tfile->next);
 397         --tun->numdisabled;
 398         return tun;
 399 }
 400
 401 static void __tun_detach(struct tun_file *tfile, bool clean)
 402 {
 403         struct tun_file *ntfile;
 404         struct tun_struct *tun;
 405         struct net_device *dev;
 406
 407         tun = rtnl_dereference(tfile->tun);
 408
 409         if (tun) {
 410                 u16 index = tfile->queue_index;
 411                 BUG_ON(index >= tun->numqueues);
 412                 dev = tun->dev;
 413
 414                 rcu_assign_pointer(tun->tfiles[index],
 415                                    tun->tfiles[tun->numqueues - 1]);
 416                 rcu_assign_pointer(tfile->tun, NULL);
 417                 ntfile = rtnl_dereference(tun->tfiles[index]);
 418                 ntfile->queue_index = index;
 419
 420                 --tun->numqueues;
 421                 if (clean)
 422                         sock_put(&tfile->sk);
 423                 else
 424                         tun_disable_queue(tun, tfile);
 425
 426                 synchronize_net();
 427                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 428                 /* Drop read queue */
 429                 skb_queue_purge(&tfile->sk.sk_receive_queue);
 430                 tun_set_real_num_queues(tun);
 431         } else if (tfile->detached && clean)
 432                 tun = tun_enable_queue(tfile);
 433
 434         if (clean) {
 435                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0 &&
 436                     !(tun->flags & TUN_PERSIST))
 437                         if (tun->dev->reg_state == NETREG_REGISTERED)
 438                                 unregister_netdevice(tun->dev);
 439
 440                 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
 441                                  &tfile->socket.flags));
 442                 sk_release_kernel(&tfile->sk);
 443         }
 444 }
 445
 446 static void tun_detach(struct tun_file *tfile, bool clean)
 447 {
 448         rtnl_lock();
 449         __tun_detach(tfile, clean);
 450         rtnl_unlock();
 451 }
 452
 453 static void tun_detach_all(struct net_device *dev)
 454 {
 455         struct tun_struct *tun = netdev_priv(dev);
 456         struct tun_file *tfile, *tmp;
 457         int i, n = tun->numqueues;
 458
 459         for (i = 0; i < n; i++) {
 460                 tfile = rtnl_dereference(tun->tfiles[i]);
 461                 BUG_ON(!tfile);
 462                 wake_up_all(&tfile->wq.wait);
 463                 rcu_assign_pointer(tfile->tun, NULL);
 464                 --tun->numqueues;
 465         }
 466         BUG_ON(tun->numqueues != 0);
 467
 468         synchronize_net();
 469         for (i = 0; i < n; i++) {
 470                 tfile = rtnl_dereference(tun->tfiles[i]);
 471                 /* Drop read queue */
 472                 skb_queue_purge(&tfile->sk.sk_receive_queue);
 473                 sock_put(&tfile->sk);
 474         }
 475         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 476                 tun_enable_queue(tfile);
 477                 skb_queue_purge(&tfile->sk.sk_receive_queue);
 478                 sock_put(&tfile->sk);
 479         }
 480         BUG_ON(tun->numdisabled != 0);
 481 }
 482
 483 static int tun_attach(struct tun_struct *tun, struct file *file)
 484 {
 485         struct tun_file *tfile = file->private_data;
 486         int err;
 487
 488         err = -EINVAL;
 489         if (rtnl_dereference(tfile->tun))
 490                 goto out;
 491
 492         err = -EBUSY;
 493         if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1)
 494                 goto out;
 495
 496         err = -E2BIG;
 497         if (!tfile->detached &&
 498             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 499                 goto out;
 500
 501         err = 0;
 502
 503         /* Re-attach the filter to presist device */
 504         if (tun->filter_attached == true) {
 505                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 506                 if (!err)
 507                         goto out;
 508         }
 509         tfile->queue_index = tun->numqueues;
 510         rcu_assign_pointer(tfile->tun, tun);
 511         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 512         tun->numqueues++;
 513
 514         if (tfile->detached)
 515                 tun_enable_queue(tfile);
 516         else
 517                 sock_hold(&tfile->sk);
 518
 519         tun_set_real_num_queues(tun);
 520
 521         /* device is allowed to go away first, so no need to hold extra
 522          * refcnt.
 523          */
 524
 525 out:
 526         return err;
 527 }
 528
 529 static struct tun_struct *__tun_get(struct tun_file *tfile)
 530 {
 531         struct tun_struct *tun;
 532
 533         rcu_read_lock();
 534         tun = rcu_dereference(tfile->tun);
 535         if (tun)
 536                 dev_hold(tun->dev);
 537         rcu_read_unlock();
 538
 539         return tun;
 540 }
 541
 542 static struct tun_struct *tun_get(struct file *file)
 543 {
 544         return __tun_get(file->private_data);
 545 }
 546
 547 static void tun_put(struct tun_struct *tun)
 548 {
 549         dev_put(tun->dev);
 550 }
 551
 552 /* TAP filtering */
 553 static void addr_hash_set(u32 *mask, const u8 *addr)
 554 {
 555         int n = ether_crc(ETH_ALEN, addr) >> 26;
 556         mask[n >> 5] |= (1 << (n & 31));
 557 }
 558
 559 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 560 {
 561         int n = ether_crc(ETH_ALEN, addr) >> 26;
 562         return mask[n >> 5] & (1 << (n & 31));
 563 }
 564
 565 static int update_filter(struct tap_filter *filter, void __user *arg)
 566 {
 567         struct { u8 u[ETH_ALEN]; } *addr;
 568         struct tun_filter uf;
 569         int err, alen, n, nexact;
 570
 571         if (copy_from_user(&uf, arg, sizeof(uf)))
 572                 return -EFAULT;
 573
 574         if (!uf.count) {
 575                 /* Disabled */
 576                 filter->count = 0;
 577                 return 0;
 578         }
 579
 580         alen = ETH_ALEN * uf.count;
 581         addr = kmalloc(alen, GFP_KERNEL);
 582         if (!addr)
 583                 return -ENOMEM;
 584
 585         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 586                 err = -EFAULT;
 587                 goto done;
 588         }
 589
 590         /* The filter is updated without holding any locks. Which is
 591          * perfectly safe. We disable it first and in the worst
 592          * case we'll accept a few undesired packets. */
 593         filter->count = 0;
 594         wmb();
 595
 596         /* Use first set of addresses as an exact filter */
 597         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 598                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 599
 600         nexact = n;
 601
 602         /* Remaining multicast addresses are hashed,
 603          * unicast will leave the filter disabled. */
 604         memset(filter->mask, 0, sizeof(filter->mask));
 605         for (; n < uf.count; n++) {
 606                 if (!is_multicast_ether_addr(addr[n].u)) {
 607                         err = 0; /* no filter */
 608                         goto done;
 609                 }
 610                 addr_hash_set(filter->mask, addr[n].u);
 611         }
 612
 613         /* For ALLMULTI just set the mask to all ones.
 614          * This overrides the mask populated above. */
 615         if ((uf.flags & TUN_FLT_ALLMULTI))
 616                 memset(filter->mask, ~0, sizeof(filter->mask));
 617
 618         /* Now enable the filter */
 619         wmb();
 620         filter->count = nexact;
 621
 622         /* Return the number of exact filters */
 623         err = nexact;
 624
 625 done:
 626         kfree(addr);
 627         return err;
 628 }
 629
 630 /* Returns: 0 - drop, !=0 - accept */
 631 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 632 {
 633         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 634          * at this point. */
 635         struct ethhdr *eh = (struct ethhdr *) skb->data;
 636         int i;
 637
 638         /* Exact match */
 639         for (i = 0; i < filter->count; i++)
 640                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 641                         return 1;
 642
 643         /* Inexact match (multicast only) */
 644         if (is_multicast_ether_addr(eh->h_dest))
 645                 return addr_hash_test(filter->mask, eh->h_dest);
 646
 647         return 0;
 648 }
 649
 650 /*
 651  * Checks whether the packet is accepted or not.
 652  * Returns: 0 - drop, !=0 - accept
 653  */
 654 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 655 {
 656         if (!filter->count)
 657                 return 1;
 658
 659         return run_filter(filter, skb);
 660 }
 661
 662 /* Network device part of the driver */
 663
 664 static const struct ethtool_ops tun_ethtool_ops;
 665
 666 /* Net device detach from fd. */
 667 static void tun_net_uninit(struct net_device *dev)
 668 {
 669         tun_detach_all(dev);
 670 }
 671
 672 /* Net device open. */
 673 static int tun_net_open(struct net_device *dev)
 674 {
 675         netif_tx_start_all_queues(dev);
 676         return 0;
 677 }
 678
 679 /* Net device close. */
 680 static int tun_net_close(struct net_device *dev)
 681 {
 682         netif_tx_stop_all_queues(dev);
 683         return 0;
 684 }
 685
 686 /* Net device start xmit */
 687 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 688 {
 689         struct tun_struct *tun = netdev_priv(dev);
 690         int txq = skb->queue_mapping;
 691         struct tun_file *tfile;
 692
 693         rcu_read_lock();
 694         tfile = rcu_dereference(tun->tfiles[txq]);
 695
 696         /* Drop packet if interface is not attached */
 697         if (txq >= tun->numqueues)
 698                 goto drop;
 699
 700         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 701
 702         BUG_ON(!tfile);
 703
 704         /* Drop if the filter does not like it.
 705          * This is a noop if the filter is disabled.
 706          * Filter can be enabled only for the TAP devices. */
 707         if (!check_filter(&tun->txflt, skb))
 708                 goto drop;
 709
 710         if (tfile->socket.sk->sk_filter &&
 711             sk_filter(tfile->socket.sk, skb))
 712                 goto drop;
 713
 714         /* Limit the number of packets queued by dividing txq length with the
 715          * number of queues.
 716          */
 717         if (skb_queue_len(&tfile->socket.sk->sk_receive_queue)
 718                           >= dev->tx_queue_len / tun->numqueues)
 719                 goto drop;
 720
 721         /* Orphan the skb - required as we might hang on to it
 722          * for indefinite time. */
 723         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 724                 goto drop;
 725         skb_orphan(skb);
 726
 727         /* Enqueue packet */
 728         skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
 729
 730         /* Notify and wake up reader process */
 731         if (tfile->flags & TUN_FASYNC)
 732                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
 733         wake_up_interruptible_poll(&tfile->wq.wait, POLLIN |
 734                                    POLLRDNORM | POLLRDBAND);
 735
 736         rcu_read_unlock();
 737         return NETDEV_TX_OK;
 738
 739 drop:
 740         dev->stats.tx_dropped++;
 741         skb_tx_error(skb);
 742         kfree_skb(skb);
 743         rcu_read_unlock();
 744         return NETDEV_TX_OK;
 745 }
 746
 747 static void tun_net_mclist(struct net_device *dev)
 748 {
 749         /*
 750          * This callback is supposed to deal with mc filter in
 751          * _rx_ path and has nothing to do with the _tx_ path.
 752          * In rx path we always accept everything userspace gives us.
 753          */
 754 }
 755
 756 #define MIN_MTU 68
 757 #define MAX_MTU 65535
 758
 759 static int
 760 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 761 {
 762         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 763                 return -EINVAL;
 764         dev->mtu = new_mtu;
 765         return 0;
 766 }
 767
 768 static netdev_features_t tun_net_fix_features(struct net_device *dev,
 769         netdev_features_t features)
 770 {
 771         struct tun_struct *tun = netdev_priv(dev);
 772
 773         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 774 }
 775 #ifdef CONFIG_NET_POLL_CONTROLLER
 776 static void tun_poll_controller(struct net_device *dev)
 777 {
 778         /*
 779          * Tun only receives frames when:
 780          * 1) the char device endpoint gets data from user space
 781          * 2) the tun socket gets a sendmsg call from user space
 782          * Since both of those are syncronous operations, we are guaranteed
 783          * never to have pending data when we poll for it
 784          * so theres nothing to do here but return.
 785          * We need this though so netpoll recognizes us as an interface that
 786          * supports polling, which enables bridge devices in virt setups to
 787          * still use netconsole
 788          */
 789         return;
 790 }
 791 #endif
 792 static const struct net_device_ops tun_netdev_ops = {
 793         .ndo_uninit             = tun_net_uninit,
 794         .ndo_open               = tun_net_open,
 795         .ndo_stop               = tun_net_close,
 796         .ndo_start_xmit         = tun_net_xmit,
 797         .ndo_change_mtu         = tun_net_change_mtu,
 798         .ndo_fix_features       = tun_net_fix_features,
 799         .ndo_select_queue       = tun_select_queue,
 800 #ifdef CONFIG_NET_POLL_CONTROLLER
 801         .ndo_poll_controller    = tun_poll_controller,
 802 #endif
 803 };
 804
 805 static const struct net_device_ops tap_netdev_ops = {
 806         .ndo_uninit             = tun_net_uninit,
 807         .ndo_open               = tun_net_open,
 808         .ndo_stop               = tun_net_close,
 809         .ndo_start_xmit         = tun_net_xmit,
 810         .ndo_change_mtu         = tun_net_change_mtu,
 811         .ndo_fix_features       = tun_net_fix_features,
 812         .ndo_set_rx_mode        = tun_net_mclist,
 813         .ndo_set_mac_address    = eth_mac_addr,
 814         .ndo_validate_addr      = eth_validate_addr,
 815         .ndo_select_queue       = tun_select_queue,
 816 #ifdef CONFIG_NET_POLL_CONTROLLER
 817         .ndo_poll_controller    = tun_poll_controller,
 818 #endif
 819 };
 820
 821 static int tun_flow_init(struct tun_struct *tun)
 822 {
 823         int i;
 824
 825         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
 826                 INIT_HLIST_HEAD(&tun->flows[i]);
 827
 828         tun->ageing_time = TUN_FLOW_EXPIRE;
 829         setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
 830         mod_timer(&tun->flow_gc_timer,
 831                   round_jiffies_up(jiffies + tun->ageing_time));
 832
 833         return 0;
 834 }
 835
 836 static void tun_flow_uninit(struct tun_struct *tun)
 837 {
 838         del_timer_sync(&tun->flow_gc_timer);
 839         tun_flow_flush(tun);
 840 }
 841
 842 /* Initialize net device. */
 843 static void tun_net_init(struct net_device *dev)
 844 {
 845         struct tun_struct *tun = netdev_priv(dev);
 846
 847         switch (tun->flags & TUN_TYPE_MASK) {
 848         case TUN_TUN_DEV:
 849                 dev->netdev_ops = &tun_netdev_ops;
 850
 851                 /* Point-to-Point TUN Device */
 852                 dev->hard_header_len = 0;
 853                 dev->addr_len = 0;
 854                 dev->mtu = 1500;
 855
 856                 /* Zero header length */
 857                 dev->type = ARPHRD_NONE;
 858                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 859                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 860                 break;
 861
 862         case TUN_TAP_DEV:
 863                 dev->netdev_ops = &tap_netdev_ops;
 864                 /* Ethernet TAP Device */
 865                 ether_setup(dev);
 866                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 867                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
 868
 869                 eth_hw_addr_random(dev);
 870
 871                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 872                 break;
 873         }
 874 }
 875
 876 /* Character device part */
 877
 878 /* Poll */
 879 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
 880 {
 881         struct tun_file *tfile = file->private_data;
 882         struct tun_struct *tun = __tun_get(tfile);
 883         struct sock *sk;
 884         unsigned int mask = 0;
 885
 886         if (!tun)
 887                 return POLLERR;
 888
 889         sk = tfile->socket.sk;
 890
 891         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
 892
 893         poll_wait(file, &tfile->wq.wait, wait);
 894
 895         if (!skb_queue_empty(&sk->sk_receive_queue))
 896                 mask |= POLLIN | POLLRDNORM;
 897
 898         if (sock_writeable(sk) ||
 899             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 900              sock_writeable(sk)))
 901                 mask |= POLLOUT | POLLWRNORM;
 902
 903         if (tun->dev->reg_state != NETREG_REGISTERED)
 904                 mask = POLLERR;
 905
 906         tun_put(tun);
 907         return mask;
 908 }
 909
 910 /* prepad is the amount to reserve at front.  len is length after that.
 911  * linear is a hint as to how much to copy (usually headers). */
 912 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
 913                                      size_t prepad, size_t len,
 914                                      size_t linear, int noblock)
 915 {
 916         struct sock *sk = tfile->socket.sk;
 917         struct sk_buff *skb;
 918         int err;
 919
 920         /* Under a page?  Don't bother with paged skb. */
 921         if (prepad + len < PAGE_SIZE || !linear)
 922                 linear = len;
 923
 924         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 925                                    &err);
 926         if (!skb)
 927                 return ERR_PTR(err);
 928
 929         skb_reserve(skb, prepad);
 930         skb_put(skb, linear);
 931         skb->data_len = len - linear;
 932         skb->len += len - linear;
 933
 934         return skb;
 935 }
 936
 937 /* set skb frags from iovec, this can move to core network code for reuse */
 938 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
 939                                   int offset, size_t count)
 940 {
 941         int len = iov_length(from, count) - offset;
 942         int copy = skb_headlen(skb);
 943         int size, offset1 = 0;
 944         int i = 0;
 945
 946         /* Skip over from offset */
 947         while (count && (offset >= from->iov_len)) {
 948                 offset -= from->iov_len;
 949                 ++from;
 950                 --count;
 951         }
 952
 953         /* copy up to skb headlen */
 954         while (count && (copy > 0)) {
 955                 size = min_t(unsigned int, copy, from->iov_len - offset);
 956                 if (copy_from_user(skb->data + offset1, from->iov_base + offset,
 957                                    size))
 958                         return -EFAULT;
 959                 if (copy > size) {
 960                         ++from;
 961                         --count;
 962                         offset = 0;
 963                 } else
 964                         offset += size;
 965                 copy -= size;
 966                 offset1 += size;
 967         }
 968
 969         if (len == offset1)
 970                 return 0;
 971
 972         while (count--) {
 973                 struct page *page[MAX_SKB_FRAGS];
 974                 int num_pages;
 975                 unsigned long base;
 976                 unsigned long truesize;
 977
 978                 len = from->iov_len - offset;
 979                 if (!len) {
 980                         offset = 0;
 981                         ++from;
 982                         continue;
 983                 }
 984                 base = (unsigned long)from->iov_base + offset;
 985                 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
 986                 if (i + size > MAX_SKB_FRAGS)
 987                         return -EMSGSIZE;
 988                 num_pages = get_user_pages_fast(base, size, 0, &page[i]);
 989                 if (num_pages != size) {
 990                         for (i = 0; i < num_pages; i++)
 991                                 put_page(page[i]);
 992                         return -EFAULT;
 993                 }
 994                 truesize = size * PAGE_SIZE;
 995                 skb->data_len += len;
 996                 skb->len += len;
 997                 skb->truesize += truesize;
 998                 atomic_add(truesize, &skb->sk->sk_wmem_alloc);
 999                 while (len) {
1000                         int off = base & ~PAGE_MASK;
1001                         int size = min_t(int, len, PAGE_SIZE - off);
1002                         __skb_fill_page_desc(skb, i, page[i], off, size);
1003                         skb_shinfo(skb)->nr_frags++;
1004                         /* increase sk_wmem_alloc */
1005                         base += size;
1006                         len -= size;
1007                         i++;
1008                 }
1009                 offset = 0;
1010                 ++from;
1011         }
1012         return 0;
1013 }
1014
1015 /* Get packet from user space buffer */
1016 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1017                             void *msg_control, const struct iovec *iv,
1018                             size_t total_len, size_t count, int noblock)
1019 {
1020         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1021         struct sk_buff *skb;
1022         size_t len = total_len, align = NET_SKB_PAD;
1023         struct virtio_net_hdr gso = { 0 };
1024         int offset = 0;
1025         int copylen;
1026         bool zerocopy = false;
1027         int err;
1028         u32 rxhash;
1029
1030         if (!(tun->flags & TUN_NO_PI)) {
1031                 if ((len -= sizeof(pi)) > total_len)
1032                         return -EINVAL;
1033
1034                 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
1035                         return -EFAULT;
1036                 offset += sizeof(pi);
1037         }
1038
1039         if (tun->flags & TUN_VNET_HDR) {
1040                 if ((len -= tun->vnet_hdr_sz) > total_len)
1041                         return -EINVAL;
1042
1043                 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
1044                         return -EFAULT;
1045
1046                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1047                     gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
1048                         gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
1049
1050                 if (gso.hdr_len > len)
1051                         return -EINVAL;
1052                 offset += tun->vnet_hdr_sz;
1053         }
1054
1055         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
1056                 align += NET_IP_ALIGN;
1057                 if (unlikely(len < ETH_HLEN ||
1058                              (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
1059                         return -EINVAL;
1060         }
1061
1062         if (msg_control)
1063                 zerocopy = true;
1064
1065         if (zerocopy) {
1066                 /* Userspace may produce vectors with count greater than
1067                  * MAX_SKB_FRAGS, so we need to linearize parts of the skb
1068                  * to let the rest of data to be fit in the frags.
1069                  */
1070                 if (count > MAX_SKB_FRAGS) {
1071                         copylen = iov_length(iv, count - MAX_SKB_FRAGS);
1072                         if (copylen < offset)
1073                                 copylen = 0;
1074                         else
1075                                 copylen -= offset;
1076                 } else
1077                                 copylen = 0;
1078                 /* There are 256 bytes to be copied in skb, so there is enough
1079                  * room for skb expand head in case it is used.
1080                  * The rest of the buffer is mapped from userspace.
1081                  */
1082                 if (copylen < gso.hdr_len)
1083                         copylen = gso.hdr_len;
1084                 if (!copylen)
1085                         copylen = GOODCOPY_LEN;
1086         } else
1087                 copylen = len;
1088
1089         skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, noblock);
1090         if (IS_ERR(skb)) {
1091                 if (PTR_ERR(skb) != -EAGAIN)
1092                         tun->dev->stats.rx_dropped++;
1093                 return PTR_ERR(skb);
1094         }
1095
1096         if (zerocopy)
1097                 err = zerocopy_sg_from_iovec(skb, iv, offset, count);
1098         else
1099                 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
1100
1101         if (err) {
1102                 tun->dev->stats.rx_dropped++;
1103                 kfree_skb(skb);
1104                 return -EFAULT;
1105         }
1106
1107         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1108                 if (!skb_partial_csum_set(skb, gso.csum_start,
1109                                           gso.csum_offset)) {
1110                         tun->dev->stats.rx_frame_errors++;
1111                         kfree_skb(skb);
1112                         return -EINVAL;
1113                 }
1114         }
1115
1116         switch (tun->flags & TUN_TYPE_MASK) {
1117         case TUN_TUN_DEV:
1118                 if (tun->flags & TUN_NO_PI) {
1119                         switch (skb->data[0] & 0xf0) {
1120                         case 0x40:
1121                                 pi.proto = htons(ETH_P_IP);
1122                                 break;
1123                         case 0x60:
1124                                 pi.proto = htons(ETH_P_IPV6);
1125                                 break;
1126                         default:
1127                                 tun->dev->stats.rx_dropped++;
1128                                 kfree_skb(skb);
1129                                 return -EINVAL;
1130                         }
1131                 }
1132
1133                 skb_reset_mac_header(skb);
1134                 skb->protocol = pi.proto;
1135                 skb->dev = tun->dev;
1136                 break;
1137         case TUN_TAP_DEV:
1138                 skb->protocol = eth_type_trans(skb, tun->dev);
1139                 break;
1140         }
1141
1142         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1143                 pr_debug("GSO!\n");
1144                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1145                 case VIRTIO_NET_HDR_GSO_TCPV4:
1146                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1147                         break;
1148                 case VIRTIO_NET_HDR_GSO_TCPV6:
1149                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1150                         break;
1151                 case VIRTIO_NET_HDR_GSO_UDP:
1152                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1153                         break;
1154                 default:
1155                         tun->dev->stats.rx_frame_errors++;
1156                         kfree_skb(skb);
1157                         return -EINVAL;
1158                 }
1159
1160                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1161                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1162
1163                 skb_shinfo(skb)->gso_size = gso.gso_size;
1164                 if (skb_shinfo(skb)->gso_size == 0) {
1165                         tun->dev->stats.rx_frame_errors++;
1166                         kfree_skb(skb);
1167                         return -EINVAL;
1168                 }
1169
1170                 /* Header must be checked, and gso_segs computed. */
1171                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1172                 skb_shinfo(skb)->gso_segs = 0;
1173         }
1174
1175         /* copy skb_ubuf_info for callback when skb has no error */
1176         if (zerocopy) {
1177                 skb_shinfo(skb)->destructor_arg = msg_control;
1178                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1179         }
1180
1181         skb_reset_network_header(skb);
1182         rxhash = skb_get_rxhash(skb);
1183         netif_rx_ni(skb);
1184
1185         tun->dev->stats.rx_packets++;
1186         tun->dev->stats.rx_bytes += len;
1187
1188         tun_flow_update(tun, rxhash, tfile->queue_index);
1189         return total_len;
1190 }
1191
1192 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
1193                               unsigned long count, loff_t pos)
1194 {
1195         struct file *file = iocb->ki_filp;
1196         struct tun_struct *tun = tun_get(file);
1197         struct tun_file *tfile = file->private_data;
1198         ssize_t result;
1199
1200         if (!tun)
1201                 return -EBADFD;
1202
1203         tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
1204
1205         result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count),
1206                               count, file->f_flags & O_NONBLOCK);
1207
1208         tun_put(tun);
1209         return result;
1210 }
1211
1212 /* Put packet to the user space buffer */
1213 static ssize_t tun_put_user(struct tun_struct *tun,
1214                             struct tun_file *tfile,
1215                             struct sk_buff *skb,
1216                             const struct iovec *iv, int len)
1217 {
1218         struct tun_pi pi = { 0, skb->protocol };
1219         ssize_t total = 0;
1220
1221         if (!(tun->flags & TUN_NO_PI)) {
1222                 if ((len -= sizeof(pi)) < 0)
1223                         return -EINVAL;
1224
1225                 if (len < skb->len) {
1226                         /* Packet will be striped */
1227                         pi.flags |= TUN_PKT_STRIP;
1228                 }
1229
1230                 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
1231                         return -EFAULT;
1232                 total += sizeof(pi);
1233         }
1234
1235         if (tun->flags & TUN_VNET_HDR) {
1236                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1237                 if ((len -= tun->vnet_hdr_sz) < 0)
1238                         return -EINVAL;
1239
1240                 if (skb_is_gso(skb)) {
1241                         struct skb_shared_info *sinfo = skb_shinfo(skb);
1242
1243                         /* This is a hint as to how much should be linear. */
1244                         gso.hdr_len = skb_headlen(skb);
1245                         gso.gso_size = sinfo->gso_size;
1246                         if (sinfo->gso_type & SKB_GSO_TCPV4)
1247                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1248                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
1249                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1250                         else if (sinfo->gso_type & SKB_GSO_UDP)
1251                                 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1252                         else {
1253                                 pr_err("unexpected GSO type: "
1254                                        "0x%x, gso_size %d, hdr_len %d\n",
1255                                        sinfo->gso_type, gso.gso_size,
1256                                        gso.hdr_len);
1257                                 print_hex_dump(KERN_ERR, "tun: ",
1258                                                DUMP_PREFIX_NONE,
1259                                                16, 1, skb->head,
1260                                                min((int)gso.hdr_len, 64), true);
1261                                 WARN_ON_ONCE(1);
1262                                 return -EINVAL;
1263                         }
1264                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1265                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1266                 } else
1267                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1268
1269                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1270                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1271                         gso.csum_start = skb_checksum_start_offset(skb);
1272                         gso.csum_offset = skb->csum_offset;
1273                 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1274                         gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1275                 } /* else everything is zero */
1276
1277                 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
1278                                                sizeof(gso))))
1279                         return -EFAULT;
1280                 total += tun->vnet_hdr_sz;
1281         }
1282
1283         len = min_t(int, skb->len, len);
1284
1285         skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
1286         total += skb->len;
1287
1288         tun->dev->stats.tx_packets++;
1289         tun->dev->stats.tx_bytes += len;
1290
1291         return total;
1292 }
1293
1294 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1295                            struct kiocb *iocb, const struct iovec *iv,
1296                            ssize_t len, int noblock)
1297 {
1298         DECLARE_WAITQUEUE(wait, current);
1299         struct sk_buff *skb;
1300         ssize_t ret = 0;
1301
1302         tun_debug(KERN_INFO, tun, "tun_do_read\n");
1303
1304         if (unlikely(!noblock))
1305                 add_wait_queue(&tfile->wq.wait, &wait);
1306         while (len) {
1307                 current->state = TASK_INTERRUPTIBLE;
1308
1309                 /* Read frames from the queue */
1310                 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) {
1311                         if (noblock) {
1312                                 ret = -EAGAIN;
1313                                 break;
1314                         }
1315                         if (signal_pending(current)) {
1316                                 ret = -ERESTARTSYS;
1317                                 break;
1318                         }
1319                         if (tun->dev->reg_state != NETREG_REGISTERED) {
1320                                 ret = -EIO;
1321                                 break;
1322                         }
1323
1324                         /* Nothing to read, let's sleep */
1325                         schedule();
1326                         continue;
1327                 }
1328
1329                 ret = tun_put_user(tun, tfile, skb, iv, len);
1330                 kfree_skb(skb);
1331                 break;
1332         }
1333
1334         current->state = TASK_RUNNING;
1335         if (unlikely(!noblock))
1336                 remove_wait_queue(&tfile->wq.wait, &wait);
1337
1338         return ret;
1339 }
1340
1341 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1342                             unsigned long count, loff_t pos)
1343 {
1344         struct file *file = iocb->ki_filp;
1345         struct tun_file *tfile = file->private_data;
1346         struct tun_struct *tun = __tun_get(tfile);
1347         ssize_t len, ret;
1348
1349         if (!tun)
1350                 return -EBADFD;
1351         len = iov_length(iv, count);
1352         if (len < 0) {
1353                 ret = -EINVAL;
1354                 goto out;
1355         }
1356
1357         ret = tun_do_read(tun, tfile, iocb, iv, len,
1358                           file->f_flags & O_NONBLOCK);
1359         ret = min_t(ssize_t, ret, len);
1360 out:
1361         tun_put(tun);
1362         return ret;
1363 }
1364
1365 static void tun_free_netdev(struct net_device *dev)
1366 {
1367         struct tun_struct *tun = netdev_priv(dev);
1368
1369         BUG_ON(!(list_empty(&tun->disabled)));
1370         tun_flow_uninit(tun);
1371         free_netdev(dev);
1372 }
1373
1374 static void tun_setup(struct net_device *dev)
1375 {
1376         struct tun_struct *tun = netdev_priv(dev);
1377
1378         tun->owner = INVALID_UID;
1379         tun->group = INVALID_GID;
1380
1381         dev->ethtool_ops = &tun_ethtool_ops;
1382         dev->destructor = tun_free_netdev;
1383 }
1384
1385 /* Trivial set of netlink ops to allow deleting tun or tap
1386  * device with netlink.
1387  */
1388 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1389 {
1390         return -EINVAL;
1391 }
1392
1393 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1394         .kind           = DRV_NAME,
1395         .priv_size      = sizeof(struct tun_struct),
1396         .setup          = tun_setup,
1397         .validate       = tun_validate,
1398 };
1399
1400 static void tun_sock_write_space(struct sock *sk)
1401 {
1402         struct tun_file *tfile;
1403         wait_queue_head_t *wqueue;
1404
1405         if (!sock_writeable(sk))
1406                 return;
1407
1408         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1409                 return;
1410
1411         wqueue = sk_sleep(sk);
1412         if (wqueue && waitqueue_active(wqueue))
1413                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1414                                                 POLLWRNORM | POLLWRBAND);
1415
1416         tfile = container_of(sk, struct tun_file, sk);
1417         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1418 }
1419
1420 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1421                        struct msghdr *m, size_t total_len)
1422 {
1423         int ret;
1424         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1425         struct tun_struct *tun = __tun_get(tfile);
1426
1427         if (!tun)
1428                 return -EBADFD;
1429         ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len,
1430                            m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1431         tun_put(tun);
1432         return ret;
1433 }
1434
1435
1436 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1437                        struct msghdr *m, size_t total_len,
1438                        int flags)
1439 {
1440         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1441         struct tun_struct *tun = __tun_get(tfile);
1442         int ret;
1443
1444         if (!tun)
1445                 return -EBADFD;
1446
1447         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1448                 return -EINVAL;
1449         ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len,
1450                           flags & MSG_DONTWAIT);
1451         if (ret > total_len) {
1452                 m->msg_flags |= MSG_TRUNC;
1453                 ret = flags & MSG_TRUNC ? ret : total_len;
1454         }
1455         tun_put(tun);
1456         return ret;
1457 }
1458
1459 static int tun_release(struct socket *sock)
1460 {
1461         if (sock->sk)
1462                 sock_put(sock->sk);
1463         return 0;
1464 }
1465
1466 /* Ops structure to mimic raw sockets with tun */
1467 static const struct proto_ops tun_socket_ops = {
1468         .sendmsg = tun_sendmsg,
1469         .recvmsg = tun_recvmsg,
1470         .release = tun_release,
1471 };
1472
1473 static struct proto tun_proto = {
1474         .name           = "tun",
1475         .owner          = THIS_MODULE,
1476         .obj_size       = sizeof(struct tun_file),
1477 };
1478
1479 static int tun_flags(struct tun_struct *tun)
1480 {
1481         int flags = 0;
1482
1483         if (tun->flags & TUN_TUN_DEV)
1484                 flags |= IFF_TUN;
1485         else
1486                 flags |= IFF_TAP;
1487
1488         if (tun->flags & TUN_NO_PI)
1489                 flags |= IFF_NO_PI;
1490
1491         /* This flag has no real effect.  We track the value for backwards
1492          * compatibility.
1493          */
1494         if (tun->flags & TUN_ONE_QUEUE)
1495                 flags |= IFF_ONE_QUEUE;
1496
1497         if (tun->flags & TUN_VNET_HDR)
1498                 flags |= IFF_VNET_HDR;
1499
1500         if (tun->flags & TUN_TAP_MQ)
1501                 flags |= IFF_MULTI_QUEUE;
1502
1503         return flags;
1504 }
1505
1506 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1507                               char *buf)
1508 {
1509         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1510         return sprintf(buf, "0x%x\n", tun_flags(tun));
1511 }
1512
1513 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1514                               char *buf)
1515 {
1516         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1517         return uid_valid(tun->owner)?
1518                 sprintf(buf, "%u\n",
1519                         from_kuid_munged(current_user_ns(), tun->owner)):
1520                 sprintf(buf, "-1\n");
1521 }
1522
1523 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1524                               char *buf)
1525 {
1526         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1527         return gid_valid(tun->group) ?
1528                 sprintf(buf, "%u\n",
1529                         from_kgid_munged(current_user_ns(), tun->group)):
1530                 sprintf(buf, "-1\n");
1531 }
1532
1533 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1534 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1535 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1536
1537 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1538 {
1539         struct tun_struct *tun;
1540         struct tun_file *tfile = file->private_data;
1541         struct net_device *dev;
1542         int err;
1543
1544         if (tfile->detached)
1545                 return -EINVAL;
1546
1547         dev = __dev_get_by_name(net, ifr->ifr_name);
1548         if (dev) {
1549                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1550                         return -EBUSY;
1551                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1552                         tun = netdev_priv(dev);
1553                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1554                         tun = netdev_priv(dev);
1555                 else
1556                         return -EINVAL;
1557
1558                 if (tun_not_capable(tun))
1559                         return -EPERM;
1560                 err = security_tun_dev_attach(tfile->socket.sk);
1561                 if (err < 0)
1562                         return err;
1563
1564                 err = tun_attach(tun, file);
1565                 if (err < 0)
1566                         return err;
1567
1568                 if (tun->flags & TUN_TAP_MQ &&
1569                     (tun->numqueues + tun->numdisabled > 1))
1570                         return err;
1571         }
1572         else {
1573                 char *name;
1574                 unsigned long flags = 0;
1575
1576                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1577                         return -EPERM;
1578                 err = security_tun_dev_create();
1579                 if (err < 0)
1580                         return err;
1581
1582                 /* Set dev type */
1583                 if (ifr->ifr_flags & IFF_TUN) {
1584                         /* TUN device */
1585                         flags |= TUN_TUN_DEV;
1586                         name = "tun%d";
1587                 } else if (ifr->ifr_flags & IFF_TAP) {
1588                         /* TAP device */
1589                         flags |= TUN_TAP_DEV;
1590                         name = "tap%d";
1591                 } else
1592                         return -EINVAL;
1593
1594                 if (*ifr->ifr_name)
1595                         name = ifr->ifr_name;
1596
1597                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1598                                        tun_setup,
1599                                        MAX_TAP_QUEUES, MAX_TAP_QUEUES);
1600                 if (!dev)
1601                         return -ENOMEM;
1602
1603                 dev_net_set(dev, net);
1604                 dev->rtnl_link_ops = &tun_link_ops;
1605
1606                 tun = netdev_priv(dev);
1607                 tun->dev = dev;
1608                 tun->flags = flags;
1609                 tun->txflt.count = 0;
1610                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1611
1612                 tun->filter_attached = false;
1613                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1614
1615                 spin_lock_init(&tun->lock);
1616
1617                 security_tun_dev_post_create(&tfile->sk);
1618
1619                 tun_net_init(dev);
1620
1621                 err = tun_flow_init(tun);
1622                 if (err < 0)
1623                         goto err_free_dev;
1624
1625                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1626                         TUN_USER_FEATURES;
1627                 dev->features = dev->hw_features;
1628
1629                 INIT_LIST_HEAD(&tun->disabled);
1630                 err = tun_attach(tun, file);
1631                 if (err < 0)
1632                         goto err_free_dev;
1633
1634                 err = register_netdevice(tun->dev);
1635                 if (err < 0)
1636                         goto err_free_dev;
1637
1638                 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1639                     device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1640                     device_create_file(&tun->dev->dev, &dev_attr_group))
1641                         pr_err("Failed to create tun sysfs files\n");
1642
1643                 netif_carrier_on(tun->dev);
1644         }
1645
1646         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1647
1648         if (ifr->ifr_flags & IFF_NO_PI)
1649                 tun->flags |= TUN_NO_PI;
1650         else
1651                 tun->flags &= ~TUN_NO_PI;
1652
1653         /* This flag has no real effect.  We track the value for backwards
1654          * compatibility.
1655          */
1656         if (ifr->ifr_flags & IFF_ONE_QUEUE)
1657                 tun->flags |= TUN_ONE_QUEUE;
1658         else
1659                 tun->flags &= ~TUN_ONE_QUEUE;
1660
1661         if (ifr->ifr_flags & IFF_VNET_HDR)
1662                 tun->flags |= TUN_VNET_HDR;
1663         else
1664                 tun->flags &= ~TUN_VNET_HDR;
1665
1666         if (ifr->ifr_flags & IFF_MULTI_QUEUE)
1667                 tun->flags |= TUN_TAP_MQ;
1668         else
1669                 tun->flags &= ~TUN_TAP_MQ;
1670
1671         /* Make sure persistent devices do not get stuck in
1672          * xoff state.
1673          */
1674         if (netif_running(tun->dev))
1675                 netif_tx_wake_all_queues(tun->dev);
1676
1677         strcpy(ifr->ifr_name, tun->dev->name);
1678         return 0;
1679
1680  err_free_dev:
1681         free_netdev(dev);
1682         return err;
1683 }
1684
1685 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1686                        struct ifreq *ifr)
1687 {
1688         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1689
1690         strcpy(ifr->ifr_name, tun->dev->name);
1691
1692         ifr->ifr_flags = tun_flags(tun);
1693
1694 }
1695
1696 /* This is like a cut-down ethtool ops, except done via tun fd so no
1697  * privs required. */
1698 static int set_offload(struct tun_struct *tun, unsigned long arg)
1699 {
1700         netdev_features_t features = 0;
1701
1702         if (arg & TUN_F_CSUM) {
1703                 features |= NETIF_F_HW_CSUM;
1704                 arg &= ~TUN_F_CSUM;
1705
1706                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1707                         if (arg & TUN_F_TSO_ECN) {
1708                                 features |= NETIF_F_TSO_ECN;
1709                                 arg &= ~TUN_F_TSO_ECN;
1710                         }
1711                         if (arg & TUN_F_TSO4)
1712                                 features |= NETIF_F_TSO;
1713                         if (arg & TUN_F_TSO6)
1714                                 features |= NETIF_F_TSO6;
1715                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1716                 }
1717
1718                 if (arg & TUN_F_UFO) {
1719                         features |= NETIF_F_UFO;
1720                         arg &= ~TUN_F_UFO;
1721                 }
1722         }
1723
1724         /* This gives the user a way to test for new features in future by
1725          * trying to set them. */
1726         if (arg)
1727                 return -EINVAL;
1728
1729         tun->set_features = features;
1730         netdev_update_features(tun->dev);
1731
1732         return 0;
1733 }
1734
1735 static void tun_detach_filter(struct tun_struct *tun, int n)
1736 {
1737         int i;
1738         struct tun_file *tfile;
1739
1740         for (i = 0; i < n; i++) {
1741                 tfile = rtnl_dereference(tun->tfiles[i]);
1742                 sk_detach_filter(tfile->socket.sk);
1743         }
1744
1745         tun->filter_attached = false;
1746 }
1747
1748 static int tun_attach_filter(struct tun_struct *tun)
1749 {
1750         int i, ret = 0;
1751         struct tun_file *tfile;
1752
1753         for (i = 0; i < tun->numqueues; i++) {
1754                 tfile = rtnl_dereference(tun->tfiles[i]);
1755                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1756                 if (ret) {
1757                         tun_detach_filter(tun, i);
1758                         return ret;
1759                 }
1760         }
1761
1762         tun->filter_attached = true;
1763         return ret;
1764 }
1765
1766 static void tun_set_sndbuf(struct tun_struct *tun)
1767 {
1768         struct tun_file *tfile;
1769         int i;
1770
1771         for (i = 0; i < tun->numqueues; i++) {
1772                 tfile = rtnl_dereference(tun->tfiles[i]);
1773                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1774         }
1775 }
1776
1777 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1778 {
1779         struct tun_file *tfile = file->private_data;
1780         struct tun_struct *tun;
1781         int ret = 0;
1782
1783         rtnl_lock();
1784
1785         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1786                 tun = tfile->detached;
1787                 if (!tun)
1788                         ret = -EINVAL;
1789                 else
1790                         ret = tun_attach(tun, file);
1791         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1792                 tun = rtnl_dereference(tfile->tun);
1793                 if (!tun || !(tun->flags & TUN_TAP_MQ))
1794                         ret = -EINVAL;
1795                 else
1796                         __tun_detach(tfile, false);
1797         } else
1798                 ret = -EINVAL;
1799
1800         rtnl_unlock();
1801         return ret;
1802 }
1803
1804 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1805                             unsigned long arg, int ifreq_len)
1806 {
1807         struct tun_file *tfile = file->private_data;
1808         struct tun_struct *tun;
1809         void __user* argp = (void __user*)arg;
1810         struct ifreq ifr;
1811         kuid_t owner;
1812         kgid_t group;
1813         int sndbuf;
1814         int vnet_hdr_sz;
1815         int ret;
1816
1817         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1818                 if (copy_from_user(&ifr, argp, ifreq_len))
1819                         return -EFAULT;
1820         } else {
1821                 memset(&ifr, 0, sizeof(ifr));
1822         }
1823         if (cmd == TUNGETFEATURES) {
1824                 /* Currently this just means: "what IFF flags are valid?".
1825                  * This is needed because we never checked for invalid flags on
1826                  * TUNSETIFF. */
1827                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1828                                 IFF_VNET_HDR | IFF_MULTI_QUEUE,
1829                                 (unsigned int __user*)argp);
1830         } else if (cmd == TUNSETQUEUE)
1831                 return tun_set_queue(file, &ifr);
1832
1833         ret = 0;
1834         rtnl_lock();
1835
1836         tun = __tun_get(tfile);
1837         if (cmd == TUNSETIFF && !tun) {
1838                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1839
1840                 ret = tun_set_iff(tfile->net, file, &ifr);
1841
1842                 if (ret)
1843                         goto unlock;
1844
1845                 if (copy_to_user(argp, &ifr, ifreq_len))
1846                         ret = -EFAULT;
1847                 goto unlock;
1848         }
1849
1850         ret = -EBADFD;
1851         if (!tun)
1852                 goto unlock;
1853
1854         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1855
1856         ret = 0;
1857         switch (cmd) {
1858         case TUNGETIFF:
1859                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1860
1861                 if (copy_to_user(argp, &ifr, ifreq_len))
1862                         ret = -EFAULT;
1863                 break;
1864
1865         case TUNSETNOCSUM:
1866                 /* Disable/Enable checksum */
1867
1868                 /* [unimplemented] */
1869                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1870                           arg ? "disabled" : "enabled");
1871                 break;
1872
1873         case TUNSETPERSIST:
1874                 /* Disable/Enable persist mode. Keep an extra reference to the
1875                  * module to prevent the module being unprobed.
1876                  */
1877                 if (arg) {
1878                         tun->flags |= TUN_PERSIST;
1879                         __module_get(THIS_MODULE);
1880                 } else {
1881                         tun->flags &= ~TUN_PERSIST;
1882                         module_put(THIS_MODULE);
1883                 }
1884
1885                 tun_debug(KERN_INFO, tun, "persist %s\n",
1886                           arg ? "enabled" : "disabled");
1887                 break;
1888
1889         case TUNSETOWNER:
1890                 /* Set owner of the device */
1891                 owner = make_kuid(current_user_ns(), arg);
1892                 if (!uid_valid(owner)) {
1893                         ret = -EINVAL;
1894                         break;
1895                 }
1896                 tun->owner = owner;
1897                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
1898                           from_kuid(&init_user_ns, tun->owner));
1899                 break;
1900
1901         case TUNSETGROUP:
1902                 /* Set group of the device */
1903                 group = make_kgid(current_user_ns(), arg);
1904                 if (!gid_valid(group)) {
1905                         ret = -EINVAL;
1906                         break;
1907                 }
1908                 tun->group = group;
1909                 tun_debug(KERN_INFO, tun, "group set to %u\n",
1910                           from_kgid(&init_user_ns, tun->group));
1911                 break;
1912
1913         case TUNSETLINK:
1914                 /* Only allow setting the type when the interface is down */
1915                 if (tun->dev->flags & IFF_UP) {
1916                         tun_debug(KERN_INFO, tun,
1917                                   "Linktype set failed because interface is up\n");
1918                         ret = -EBUSY;
1919                 } else {
1920                         tun->dev->type = (int) arg;
1921                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1922                                   tun->dev->type);
1923                         ret = 0;
1924                 }
1925                 break;
1926
1927 #ifdef TUN_DEBUG
1928         case TUNSETDEBUG:
1929                 tun->debug = arg;
1930                 break;
1931 #endif
1932         case TUNSETOFFLOAD:
1933                 ret = set_offload(tun, arg);
1934                 break;
1935
1936         case TUNSETTXFILTER:
1937                 /* Can be set only for TAPs */
1938                 ret = -EINVAL;
1939                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1940                         break;
1941                 ret = update_filter(&tun->txflt, (void __user *)arg);
1942                 break;
1943
1944         case SIOCGIFHWADDR:
1945                 /* Get hw address */
1946                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1947                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1948                 if (copy_to_user(argp, &ifr, ifreq_len))
1949                         ret = -EFAULT;
1950                 break;
1951
1952         case SIOCSIFHWADDR:
1953                 /* Set hw address */
1954                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1955                           ifr.ifr_hwaddr.sa_data);
1956
1957                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1958                 break;
1959
1960         case TUNGETSNDBUF:
1961                 sndbuf = tfile->socket.sk->sk_sndbuf;
1962                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1963                         ret = -EFAULT;
1964                 break;
1965
1966         case TUNSETSNDBUF:
1967                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1968                         ret = -EFAULT;
1969                         break;
1970                 }
1971
1972                 tun->sndbuf = sndbuf;
1973                 tun_set_sndbuf(tun);
1974                 break;
1975
1976         case TUNGETVNETHDRSZ:
1977                 vnet_hdr_sz = tun->vnet_hdr_sz;
1978                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
1979                         ret = -EFAULT;
1980                 break;
1981
1982         case TUNSETVNETHDRSZ:
1983                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
1984                         ret = -EFAULT;
1985                         break;
1986                 }
1987                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
1988                         ret = -EINVAL;
1989                         break;
1990                 }
1991
1992                 tun->vnet_hdr_sz = vnet_hdr_sz;
1993                 break;
1994
1995         case TUNATTACHFILTER:
1996                 /* Can be set only for TAPs */
1997                 ret = -EINVAL;
1998                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1999                         break;
2000                 ret = -EFAULT;
2001                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2002                         break;
2003
2004                 ret = tun_attach_filter(tun);
2005                 break;
2006
2007         case TUNDETACHFILTER:
2008                 /* Can be set only for TAPs */
2009                 ret = -EINVAL;
2010                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2011                         break;
2012                 ret = 0;
2013                 tun_detach_filter(tun, tun->numqueues);
2014                 break;
2015
2016         default:
2017                 ret = -EINVAL;
2018                 break;
2019         }
2020
2021 unlock:
2022         rtnl_unlock();
2023         if (tun)
2024                 tun_put(tun);
2025         return ret;
2026 }
2027
2028 static long tun_chr_ioctl(struct file *file,
2029                           unsigned int cmd, unsigned long arg)
2030 {
2031         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2032 }
2033
2034 #ifdef CONFIG_COMPAT
2035 static long tun_chr_compat_ioctl(struct file *file,
2036                          unsigned int cmd, unsigned long arg)
2037 {
2038         switch (cmd) {
2039         case TUNSETIFF:
2040         case TUNGETIFF:
2041         case TUNSETTXFILTER:
2042         case TUNGETSNDBUF:
2043         case TUNSETSNDBUF:
2044         case SIOCGIFHWADDR:
2045         case SIOCSIFHWADDR:
2046                 arg = (unsigned long)compat_ptr(arg);
2047                 break;
2048         default:
2049                 arg = (compat_ulong_t)arg;
2050                 break;
2051         }
2052
2053         /*
2054          * compat_ifreq is shorter than ifreq, so we must not access beyond
2055          * the end of that structure. All fields that are used in this
2056          * driver are compatible though, we don't need to convert the
2057          * contents.
2058          */
2059         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2060 }
2061 #endif /* CONFIG_COMPAT */
2062
2063 static int tun_chr_fasync(int fd, struct file *file, int on)
2064 {
2065         struct tun_file *tfile = file->private_data;
2066         int ret;
2067
2068         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2069                 goto out;
2070
2071         if (on) {
2072                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2073                 if (ret)
2074                         goto out;
2075                 tfile->flags |= TUN_FASYNC;
2076         } else
2077                 tfile->flags &= ~TUN_FASYNC;
2078         ret = 0;
2079 out:
2080         return ret;
2081 }
2082
2083 static int tun_chr_open(struct inode *inode, struct file * file)
2084 {
2085         struct tun_file *tfile;
2086
2087         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2088
2089         tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
2090                                             &tun_proto);
2091         if (!tfile)
2092                 return -ENOMEM;
2093         rcu_assign_pointer(tfile->tun, NULL);
2094         tfile->net = get_net(current->nsproxy->net_ns);
2095         tfile->flags = 0;
2096
2097         rcu_assign_pointer(tfile->socket.wq, &tfile->wq);
2098         init_waitqueue_head(&tfile->wq.wait);
2099
2100         tfile->socket.file = file;
2101         tfile->socket.ops = &tun_socket_ops;
2102
2103         sock_init_data(&tfile->socket, &tfile->sk);
2104         sk_change_net(&tfile->sk, tfile->net);
2105
2106         tfile->sk.sk_write_space = tun_sock_write_space;
2107         tfile->sk.sk_sndbuf = INT_MAX;
2108
2109         file->private_data = tfile;
2110         set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
2111         INIT_LIST_HEAD(&tfile->next);
2112
2113         return 0;
2114 }
2115
2116 static int tun_chr_close(struct inode *inode, struct file *file)
2117 {
2118         struct tun_file *tfile = file->private_data;
2119         struct net *net = tfile->net;
2120
2121         tun_detach(tfile, true);
2122         put_net(net);
2123
2124         return 0;
2125 }
2126
2127 static const struct file_operations tun_fops = {
2128         .owner  = THIS_MODULE,
2129         .llseek = no_llseek,
2130         .read  = do_sync_read,
2131         .aio_read  = tun_chr_aio_read,
2132         .write = do_sync_write,
2133         .aio_write = tun_chr_aio_write,
2134         .poll   = tun_chr_poll,
2135         .unlocked_ioctl = tun_chr_ioctl,
2136 #ifdef CONFIG_COMPAT
2137         .compat_ioctl = tun_chr_compat_ioctl,
2138 #endif
2139         .open   = tun_chr_open,
2140         .release = tun_chr_close,
2141         .fasync = tun_chr_fasync
2142 };
2143
2144 static struct miscdevice tun_miscdev = {
2145         .minor = TUN_MINOR,
2146         .name = "tun",
2147         .nodename = "net/tun",
2148         .fops = &tun_fops,
2149 };
2150
2151 /* ethtool interface */
2152
2153 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2154 {
2155         cmd->supported          = 0;
2156         cmd->advertising        = 0;
2157         ethtool_cmd_speed_set(cmd, SPEED_10);
2158         cmd->duplex             = DUPLEX_FULL;
2159         cmd->port               = PORT_TP;
2160         cmd->phy_address        = 0;
2161         cmd->transceiver        = XCVR_INTERNAL;
2162         cmd->autoneg            = AUTONEG_DISABLE;
2163         cmd->maxtxpkt           = 0;
2164         cmd->maxrxpkt           = 0;
2165         return 0;
2166 }
2167
2168 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2169 {
2170         struct tun_struct *tun = netdev_priv(dev);
2171
2172         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2173         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2174
2175         switch (tun->flags & TUN_TYPE_MASK) {
2176         case TUN_TUN_DEV:
2177                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2178                 break;
2179         case TUN_TAP_DEV:
2180                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2181                 break;
2182         }
2183 }
2184
2185 static u32 tun_get_msglevel(struct net_device *dev)
2186 {
2187 #ifdef TUN_DEBUG
2188         struct tun_struct *tun = netdev_priv(dev);
2189         return tun->debug;
2190 #else
2191         return -EOPNOTSUPP;
2192 #endif
2193 }
2194
2195 static void tun_set_msglevel(struct net_device *dev, u32 value)
2196 {
2197 #ifdef TUN_DEBUG
2198         struct tun_struct *tun = netdev_priv(dev);
2199         tun->debug = value;
2200 #endif
2201 }
2202
2203 static const struct ethtool_ops tun_ethtool_ops = {
2204         .get_settings   = tun_get_settings,
2205         .get_drvinfo    = tun_get_drvinfo,
2206         .get_msglevel   = tun_get_msglevel,
2207         .set_msglevel   = tun_set_msglevel,
2208         .get_link       = ethtool_op_get_link,
2209 };
2210
2211
2212 static int __init tun_init(void)
2213 {
2214         int ret = 0;
2215
2216         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2217         pr_info("%s\n", DRV_COPYRIGHT);
2218
2219         ret = rtnl_link_register(&tun_link_ops);
2220         if (ret) {
2221                 pr_err("Can't register link_ops\n");
2222                 goto err_linkops;
2223         }
2224
2225         ret = misc_register(&tun_miscdev);
2226         if (ret) {
2227                 pr_err("Can't register misc device %d\n", TUN_MINOR);
2228                 goto err_misc;
2229         }
2230         return  0;
2231 err_misc:
2232         rtnl_link_unregister(&tun_link_ops);
2233 err_linkops:
2234         return ret;
2235 }
2236
2237 static void tun_cleanup(void)
2238 {
2239         misc_deregister(&tun_miscdev);
2240         rtnl_link_unregister(&tun_link_ops);
2241 }
2242
2243 /* Get an underlying socket object from tun file.  Returns error unless file is
2244  * attached to a device.  The returned object works like a packet socket, it
2245  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2246  * holding a reference to the file for as long as the socket is in use. */
2247 struct socket *tun_get_socket(struct file *file)
2248 {
2249         struct tun_file *tfile;
2250         if (file->f_op != &tun_fops)
2251                 return ERR_PTR(-EINVAL);
2252         tfile = file->private_data;
2253         if (!tfile)
2254                 return ERR_PTR(-EBADFD);
2255         return &tfile->socket;
2256 }
2257 EXPORT_SYMBOL_GPL(tun_get_socket);
2258
2259 module_init(tun_init);
2260 module_exit(tun_cleanup);
2261 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2262 MODULE_AUTHOR(DRV_COPYRIGHT);
2263 MODULE_LICENSE("GPL");
2264 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2265 MODULE_ALIAS("devname:net/tun");