linux/drivers/net/tun.c
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   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
  78static int debug;
  79
  80#define tun_debug(level, tun, fmt, args...)                     \
  81do {                                                            \
  82        if (tun->debug)                                         \
  83                netdev_printk(level, tun->dev, fmt, ##args);    \
  84} while (0)
  85#define DBG1(level, fmt, args...)                               \
  86do {                                                            \
  87        if (debug == 2)                                         \
  88                printk(level fmt, ##args);                      \
  89} while (0)
  90#else
  91#define tun_debug(level, tun, fmt, args...)                     \
  92do {                                                            \
  93        if (0)                                                  \
  94                netdev_printk(level, tun->dev, fmt, ##args);    \
  95} while (0)
  96#define DBG1(level, fmt, args...)                               \
  97do {                                                            \
  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
 106struct 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/* DEFAULT_MAX_NUM_RSS_QUEUES were choosed to let the rx/tx queues allocated for
 113 * the netdevice to be fit in one page. So we can make sure the success of
 114 * memory allocation. TODO: increase the limit. */
 115#define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES
 116#define MAX_TAP_FLOWS  4096
 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 */
 131struct 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
 145struct 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 */
 161struct 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        void *security;
 189        u32 flow_count;
 190};
 191
 192static inline u32 tun_hashfn(u32 rxhash)
 193{
 194        return rxhash & 0x3ff;
 195}
 196
 197static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 198{
 199        struct tun_flow_entry *e;
 200        struct hlist_node *n;
 201
 202        hlist_for_each_entry_rcu(e, n, head, hash_link) {
 203                if (e->rxhash == rxhash)
 204                        return e;
 205        }
 206        return NULL;
 207}
 208
 209static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 210                                              struct hlist_head *head,
 211                                              u32 rxhash, u16 queue_index)
 212{
 213        struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 214
 215        if (e) {
 216                tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 217                          rxhash, queue_index);
 218                e->updated = jiffies;
 219                e->rxhash = rxhash;
 220                e->queue_index = queue_index;
 221                e->tun = tun;
 222                hlist_add_head_rcu(&e->hash_link, head);
 223                ++tun->flow_count;
 224        }
 225        return e;
 226}
 227
 228static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 229{
 230        tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 231                  e->rxhash, e->queue_index);
 232        hlist_del_rcu(&e->hash_link);
 233        kfree_rcu(e, rcu);
 234        --tun->flow_count;
 235}
 236
 237static 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
 252static 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
 269static 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
 300static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 301                            struct tun_file *tfile)
 302{
 303        struct hlist_head *head;
 304        struct tun_flow_entry *e;
 305        unsigned long delay = tun->ageing_time;
 306        u16 queue_index = tfile->queue_index;
 307
 308        if (!rxhash)
 309                return;
 310        else
 311                head = &tun->flows[tun_hashfn(rxhash)];
 312
 313        rcu_read_lock();
 314
 315        /* We may get a very small possibility of OOO during switching, not
 316         * worth to optimize.*/
 317        if (tun->numqueues == 1 || tfile->detached)
 318                goto unlock;
 319
 320        e = tun_flow_find(head, rxhash);
 321        if (likely(e)) {
 322                /* TODO: keep queueing to old queue until it's empty? */
 323                e->queue_index = queue_index;
 324                e->updated = jiffies;
 325        } else {
 326                spin_lock_bh(&tun->lock);
 327                if (!tun_flow_find(head, rxhash) &&
 328                    tun->flow_count < MAX_TAP_FLOWS)
 329                        tun_flow_create(tun, head, rxhash, queue_index);
 330
 331                if (!timer_pending(&tun->flow_gc_timer))
 332                        mod_timer(&tun->flow_gc_timer,
 333                                  round_jiffies_up(jiffies + delay));
 334                spin_unlock_bh(&tun->lock);
 335        }
 336
 337unlock:
 338        rcu_read_unlock();
 339}
 340
 341/* We try to identify a flow through its rxhash first. The reason that
 342 * we do not check rxq no. is becuase some cards(e.g 82599), chooses
 343 * the rxq based on the txq where the last packet of the flow comes. As
 344 * the userspace application move between processors, we may get a
 345 * different rxq no. here. If we could not get rxhash, then we would
 346 * hope the rxq no. may help here.
 347 */
 348static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb)
 349{
 350        struct tun_struct *tun = netdev_priv(dev);
 351        struct tun_flow_entry *e;
 352        u32 txq = 0;
 353        u32 numqueues = 0;
 354
 355        rcu_read_lock();
 356        numqueues = tun->numqueues;
 357
 358        txq = skb_get_rxhash(skb);
 359        if (txq) {
 360                e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 361                if (e)
 362                        txq = e->queue_index;
 363                else
 364                        /* use multiply and shift instead of expensive divide */
 365                        txq = ((u64)txq * numqueues) >> 32;
 366        } else if (likely(skb_rx_queue_recorded(skb))) {
 367                txq = skb_get_rx_queue(skb);
 368                while (unlikely(txq >= numqueues))
 369                        txq -= numqueues;
 370        }
 371
 372        rcu_read_unlock();
 373        return txq;
 374}
 375
 376static inline bool tun_not_capable(struct tun_struct *tun)
 377{
 378        const struct cred *cred = current_cred();
 379        struct net *net = dev_net(tun->dev);
 380
 381        return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 382                  (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 383                !ns_capable(net->user_ns, CAP_NET_ADMIN);
 384}
 385
 386static void tun_set_real_num_queues(struct tun_struct *tun)
 387{
 388        netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 389        netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 390}
 391
 392static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 393{
 394        tfile->detached = tun;
 395        list_add_tail(&tfile->next, &tun->disabled);
 396        ++tun->numdisabled;
 397}
 398
 399static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 400{
 401        struct tun_struct *tun = tfile->detached;
 402
 403        tfile->detached = NULL;
 404        list_del_init(&tfile->next);
 405        --tun->numdisabled;
 406        return tun;
 407}
 408
 409static void __tun_detach(struct tun_file *tfile, bool clean)
 410{
 411        struct tun_file *ntfile;
 412        struct tun_struct *tun;
 413        struct net_device *dev;
 414
 415        tun = rtnl_dereference(tfile->tun);
 416
 417        if (tun && !tfile->detached) {
 418                u16 index = tfile->queue_index;
 419                BUG_ON(index >= tun->numqueues);
 420                dev = tun->dev;
 421
 422                rcu_assign_pointer(tun->tfiles[index],
 423                                   tun->tfiles[tun->numqueues - 1]);
 424                ntfile = rtnl_dereference(tun->tfiles[index]);
 425                ntfile->queue_index = index;
 426
 427                --tun->numqueues;
 428                if (clean) {
 429                        rcu_assign_pointer(tfile->tun, NULL);
 430                        sock_put(&tfile->sk);
 431                } else
 432                        tun_disable_queue(tun, tfile);
 433
 434                synchronize_net();
 435                tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 436                /* Drop read queue */
 437                skb_queue_purge(&tfile->sk.sk_receive_queue);
 438                tun_set_real_num_queues(tun);
 439        } else if (tfile->detached && clean) {
 440                tun = tun_enable_queue(tfile);
 441                sock_put(&tfile->sk);
 442        }
 443
 444        if (clean) {
 445                if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 446                        netif_carrier_off(tun->dev);
 447
 448                        if (!(tun->flags & TUN_PERSIST) &&
 449                            tun->dev->reg_state == NETREG_REGISTERED)
 450                                unregister_netdevice(tun->dev);
 451                }
 452
 453                BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
 454                                 &tfile->socket.flags));
 455                sk_release_kernel(&tfile->sk);
 456        }
 457}
 458
 459static void tun_detach(struct tun_file *tfile, bool clean)
 460{
 461        rtnl_lock();
 462        __tun_detach(tfile, clean);
 463        rtnl_unlock();
 464}
 465
 466static void tun_detach_all(struct net_device *dev)
 467{
 468        struct tun_struct *tun = netdev_priv(dev);
 469        struct tun_file *tfile, *tmp;
 470        int i, n = tun->numqueues;
 471
 472        for (i = 0; i < n; i++) {
 473                tfile = rtnl_dereference(tun->tfiles[i]);
 474                BUG_ON(!tfile);
 475                wake_up_all(&tfile->wq.wait);
 476                rcu_assign_pointer(tfile->tun, NULL);
 477                --tun->numqueues;
 478        }
 479        list_for_each_entry(tfile, &tun->disabled, next) {
 480                wake_up_all(&tfile->wq.wait);
 481                rcu_assign_pointer(tfile->tun, NULL);
 482        }
 483        BUG_ON(tun->numqueues != 0);
 484
 485        synchronize_net();
 486        for (i = 0; i < n; i++) {
 487                tfile = rtnl_dereference(tun->tfiles[i]);
 488                /* Drop read queue */
 489                skb_queue_purge(&tfile->sk.sk_receive_queue);
 490                sock_put(&tfile->sk);
 491        }
 492        list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 493                tun_enable_queue(tfile);
 494                skb_queue_purge(&tfile->sk.sk_receive_queue);
 495                sock_put(&tfile->sk);
 496        }
 497        BUG_ON(tun->numdisabled != 0);
 498
 499        if (tun->flags & TUN_PERSIST)
 500                module_put(THIS_MODULE);
 501}
 502
 503static int tun_attach(struct tun_struct *tun, struct file *file)
 504{
 505        struct tun_file *tfile = file->private_data;
 506        int err;
 507
 508        err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 509        if (err < 0)
 510                goto out;
 511
 512        err = -EINVAL;
 513        if (rtnl_dereference(tfile->tun) && !tfile->detached)
 514                goto out;
 515
 516        err = -EBUSY;
 517        if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1)
 518                goto out;
 519
 520        err = -E2BIG;
 521        if (!tfile->detached &&
 522            tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 523                goto out;
 524
 525        err = 0;
 526
 527        /* Re-attach the filter to presist device */
 528        if (tun->filter_attached == true) {
 529                err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 530                if (!err)
 531                        goto out;
 532        }
 533        tfile->queue_index = tun->numqueues;
 534        rcu_assign_pointer(tfile->tun, tun);
 535        rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 536        tun->numqueues++;
 537
 538        if (tfile->detached)
 539                tun_enable_queue(tfile);
 540        else
 541                sock_hold(&tfile->sk);
 542
 543        tun_set_real_num_queues(tun);
 544
 545        /* device is allowed to go away first, so no need to hold extra
 546         * refcnt.
 547         */
 548
 549out:
 550        return err;
 551}
 552
 553static struct tun_struct *__tun_get(struct tun_file *tfile)
 554{
 555        struct tun_struct *tun;
 556
 557        rcu_read_lock();
 558        tun = rcu_dereference(tfile->tun);
 559        if (tun)
 560                dev_hold(tun->dev);
 561        rcu_read_unlock();
 562
 563        return tun;
 564}
 565
 566static struct tun_struct *tun_get(struct file *file)
 567{
 568        return __tun_get(file->private_data);
 569}
 570
 571static void tun_put(struct tun_struct *tun)
 572{
 573        dev_put(tun->dev);
 574}
 575
 576/* TAP filtering */
 577static void addr_hash_set(u32 *mask, const u8 *addr)
 578{
 579        int n = ether_crc(ETH_ALEN, addr) >> 26;
 580        mask[n >> 5] |= (1 << (n & 31));
 581}
 582
 583static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 584{
 585        int n = ether_crc(ETH_ALEN, addr) >> 26;
 586        return mask[n >> 5] & (1 << (n & 31));
 587}
 588
 589static int update_filter(struct tap_filter *filter, void __user *arg)
 590{
 591        struct { u8 u[ETH_ALEN]; } *addr;
 592        struct tun_filter uf;
 593        int err, alen, n, nexact;
 594
 595        if (copy_from_user(&uf, arg, sizeof(uf)))
 596                return -EFAULT;
 597
 598        if (!uf.count) {
 599                /* Disabled */
 600                filter->count = 0;
 601                return 0;
 602        }
 603
 604        alen = ETH_ALEN * uf.count;
 605        addr = kmalloc(alen, GFP_KERNEL);
 606        if (!addr)
 607                return -ENOMEM;
 608
 609        if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 610                err = -EFAULT;
 611                goto done;
 612        }
 613
 614        /* The filter is updated without holding any locks. Which is
 615         * perfectly safe. We disable it first and in the worst
 616         * case we'll accept a few undesired packets. */
 617        filter->count = 0;
 618        wmb();
 619
 620        /* Use first set of addresses as an exact filter */
 621        for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 622                memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 623
 624        nexact = n;
 625
 626        /* Remaining multicast addresses are hashed,
 627         * unicast will leave the filter disabled. */
 628        memset(filter->mask, 0, sizeof(filter->mask));
 629        for (; n < uf.count; n++) {
 630                if (!is_multicast_ether_addr(addr[n].u)) {
 631                        err = 0; /* no filter */
 632                        goto done;
 633                }
 634                addr_hash_set(filter->mask, addr[n].u);
 635        }
 636
 637        /* For ALLMULTI just set the mask to all ones.
 638         * This overrides the mask populated above. */
 639        if ((uf.flags & TUN_FLT_ALLMULTI))
 640                memset(filter->mask, ~0, sizeof(filter->mask));
 641
 642        /* Now enable the filter */
 643        wmb();
 644        filter->count = nexact;
 645
 646        /* Return the number of exact filters */
 647        err = nexact;
 648
 649done:
 650        kfree(addr);
 651        return err;
 652}
 653
 654/* Returns: 0 - drop, !=0 - accept */
 655static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 656{
 657        /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 658         * at this point. */
 659        struct ethhdr *eh = (struct ethhdr *) skb->data;
 660        int i;
 661
 662        /* Exact match */
 663        for (i = 0; i < filter->count; i++)
 664                if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 665                        return 1;
 666
 667        /* Inexact match (multicast only) */
 668        if (is_multicast_ether_addr(eh->h_dest))
 669                return addr_hash_test(filter->mask, eh->h_dest);
 670
 671        return 0;
 672}
 673
 674/*
 675 * Checks whether the packet is accepted or not.
 676 * Returns: 0 - drop, !=0 - accept
 677 */
 678static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 679{
 680        if (!filter->count)
 681                return 1;
 682
 683        return run_filter(filter, skb);
 684}
 685
 686/* Network device part of the driver */
 687
 688static const struct ethtool_ops tun_ethtool_ops;
 689
 690/* Net device detach from fd. */
 691static void tun_net_uninit(struct net_device *dev)
 692{
 693        tun_detach_all(dev);
 694}
 695
 696/* Net device open. */
 697static int tun_net_open(struct net_device *dev)
 698{
 699        netif_tx_start_all_queues(dev);
 700        return 0;
 701}
 702
 703/* Net device close. */
 704static int tun_net_close(struct net_device *dev)
 705{
 706        netif_tx_stop_all_queues(dev);
 707        return 0;
 708}
 709
 710/* Net device start xmit */
 711static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 712{
 713        struct tun_struct *tun = netdev_priv(dev);
 714        int txq = skb->queue_mapping;
 715        struct tun_file *tfile;
 716
 717        rcu_read_lock();
 718        tfile = rcu_dereference(tun->tfiles[txq]);
 719
 720        /* Drop packet if interface is not attached */
 721        if (txq >= tun->numqueues)
 722                goto drop;
 723
 724        tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 725
 726        BUG_ON(!tfile);
 727
 728        /* Drop if the filter does not like it.
 729         * This is a noop if the filter is disabled.
 730         * Filter can be enabled only for the TAP devices. */
 731        if (!check_filter(&tun->txflt, skb))
 732                goto drop;
 733
 734        if (tfile->socket.sk->sk_filter &&
 735            sk_filter(tfile->socket.sk, skb))
 736                goto drop;
 737
 738        /* Limit the number of packets queued by dividing txq length with the
 739         * number of queues.
 740         */
 741        if (skb_queue_len(&tfile->socket.sk->sk_receive_queue)
 742                          >= dev->tx_queue_len / tun->numqueues)
 743                goto drop;
 744
 745        /* Orphan the skb - required as we might hang on to it
 746         * for indefinite time. */
 747        if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 748                goto drop;
 749        skb_orphan(skb);
 750
 751        /* Enqueue packet */
 752        skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
 753
 754        /* Notify and wake up reader process */
 755        if (tfile->flags & TUN_FASYNC)
 756                kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
 757        wake_up_interruptible_poll(&tfile->wq.wait, POLLIN |
 758                                   POLLRDNORM | POLLRDBAND);
 759
 760        rcu_read_unlock();
 761        return NETDEV_TX_OK;
 762
 763drop:
 764        dev->stats.tx_dropped++;
 765        skb_tx_error(skb);
 766        kfree_skb(skb);
 767        rcu_read_unlock();
 768        return NETDEV_TX_OK;
 769}
 770
 771static void tun_net_mclist(struct net_device *dev)
 772{
 773        /*
 774         * This callback is supposed to deal with mc filter in
 775         * _rx_ path and has nothing to do with the _tx_ path.
 776         * In rx path we always accept everything userspace gives us.
 777         */
 778}
 779
 780#define MIN_MTU 68
 781#define MAX_MTU 65535
 782
 783static int
 784tun_net_change_mtu(struct net_device *dev, int new_mtu)
 785{
 786        if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 787                return -EINVAL;
 788        dev->mtu = new_mtu;
 789        return 0;
 790}
 791
 792static netdev_features_t tun_net_fix_features(struct net_device *dev,
 793        netdev_features_t features)
 794{
 795        struct tun_struct *tun = netdev_priv(dev);
 796
 797        return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 798}
 799#ifdef CONFIG_NET_POLL_CONTROLLER
 800static void tun_poll_controller(struct net_device *dev)
 801{
 802        /*
 803         * Tun only receives frames when:
 804         * 1) the char device endpoint gets data from user space
 805         * 2) the tun socket gets a sendmsg call from user space
 806         * Since both of those are syncronous operations, we are guaranteed
 807         * never to have pending data when we poll for it
 808         * so theres nothing to do here but return.
 809         * We need this though so netpoll recognizes us as an interface that
 810         * supports polling, which enables bridge devices in virt setups to
 811         * still use netconsole
 812         */
 813        return;
 814}
 815#endif
 816static const struct net_device_ops tun_netdev_ops = {
 817        .ndo_uninit             = tun_net_uninit,
 818        .ndo_open               = tun_net_open,
 819        .ndo_stop               = tun_net_close,
 820        .ndo_start_xmit         = tun_net_xmit,
 821        .ndo_change_mtu         = tun_net_change_mtu,
 822        .ndo_fix_features       = tun_net_fix_features,
 823        .ndo_select_queue       = tun_select_queue,
 824#ifdef CONFIG_NET_POLL_CONTROLLER
 825        .ndo_poll_controller    = tun_poll_controller,
 826#endif
 827};
 828
 829static const struct net_device_ops tap_netdev_ops = {
 830        .ndo_uninit             = tun_net_uninit,
 831        .ndo_open               = tun_net_open,
 832        .ndo_stop               = tun_net_close,
 833        .ndo_start_xmit         = tun_net_xmit,
 834        .ndo_change_mtu         = tun_net_change_mtu,
 835        .ndo_fix_features       = tun_net_fix_features,
 836        .ndo_set_rx_mode        = tun_net_mclist,
 837        .ndo_set_mac_address    = eth_mac_addr,
 838        .ndo_validate_addr      = eth_validate_addr,
 839        .ndo_select_queue       = tun_select_queue,
 840#ifdef CONFIG_NET_POLL_CONTROLLER
 841        .ndo_poll_controller    = tun_poll_controller,
 842#endif
 843};
 844
 845static int tun_flow_init(struct tun_struct *tun)
 846{
 847        int i;
 848
 849        for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
 850                INIT_HLIST_HEAD(&tun->flows[i]);
 851
 852        tun->ageing_time = TUN_FLOW_EXPIRE;
 853        setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
 854        mod_timer(&tun->flow_gc_timer,
 855                  round_jiffies_up(jiffies + tun->ageing_time));
 856
 857        return 0;
 858}
 859
 860static void tun_flow_uninit(struct tun_struct *tun)
 861{
 862        del_timer_sync(&tun->flow_gc_timer);
 863        tun_flow_flush(tun);
 864}
 865
 866/* Initialize net device. */
 867static void tun_net_init(struct net_device *dev)
 868{
 869        struct tun_struct *tun = netdev_priv(dev);
 870
 871        switch (tun->flags & TUN_TYPE_MASK) {
 872        case TUN_TUN_DEV:
 873                dev->netdev_ops = &tun_netdev_ops;
 874
 875                /* Point-to-Point TUN Device */
 876                dev->hard_header_len = 0;
 877                dev->addr_len = 0;
 878                dev->mtu = 1500;
 879
 880                /* Zero header length */
 881                dev->type = ARPHRD_NONE;
 882                dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 883                dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 884                break;
 885
 886        case TUN_TAP_DEV:
 887                dev->netdev_ops = &tap_netdev_ops;
 888                /* Ethernet TAP Device */
 889                ether_setup(dev);
 890                dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 891                dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
 892
 893                eth_hw_addr_random(dev);
 894
 895                dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 896                break;
 897        }
 898}
 899
 900/* Character device part */
 901
 902/* Poll */
 903static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
 904{
 905        struct tun_file *tfile = file->private_data;
 906        struct tun_struct *tun = __tun_get(tfile);
 907        struct sock *sk;
 908        unsigned int mask = 0;
 909
 910        if (!tun)
 911                return POLLERR;
 912
 913        sk = tfile->socket.sk;
 914
 915        tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
 916
 917        poll_wait(file, &tfile->wq.wait, wait);
 918
 919        if (!skb_queue_empty(&sk->sk_receive_queue))
 920                mask |= POLLIN | POLLRDNORM;
 921
 922        if (sock_writeable(sk) ||
 923            (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 924             sock_writeable(sk)))
 925                mask |= POLLOUT | POLLWRNORM;
 926
 927        if (tun->dev->reg_state != NETREG_REGISTERED)
 928                mask = POLLERR;
 929
 930        tun_put(tun);
 931        return mask;
 932}
 933
 934/* prepad is the amount to reserve at front.  len is length after that.
 935 * linear is a hint as to how much to copy (usually headers). */
 936static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
 937                                     size_t prepad, size_t len,
 938                                     size_t linear, int noblock)
 939{
 940        struct sock *sk = tfile->socket.sk;
 941        struct sk_buff *skb;
 942        int err;
 943
 944        /* Under a page?  Don't bother with paged skb. */
 945        if (prepad + len < PAGE_SIZE || !linear)
 946                linear = len;
 947
 948        skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 949                                   &err);
 950        if (!skb)
 951                return ERR_PTR(err);
 952
 953        skb_reserve(skb, prepad);
 954        skb_put(skb, linear);
 955        skb->data_len = len - linear;
 956        skb->len += len - linear;
 957
 958        return skb;
 959}
 960
 961/* set skb frags from iovec, this can move to core network code for reuse */
 962static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
 963                                  int offset, size_t count)
 964{
 965        int len = iov_length(from, count) - offset;
 966        int copy = skb_headlen(skb);
 967        int size, offset1 = 0;
 968        int i = 0;
 969
 970        /* Skip over from offset */
 971        while (count && (offset >= from->iov_len)) {
 972                offset -= from->iov_len;
 973                ++from;
 974                --count;
 975        }
 976
 977        /* copy up to skb headlen */
 978        while (count && (copy > 0)) {
 979                size = min_t(unsigned int, copy, from->iov_len - offset);
 980                if (copy_from_user(skb->data + offset1, from->iov_base + offset,
 981                                   size))
 982                        return -EFAULT;
 983                if (copy > size) {
 984                        ++from;
 985                        --count;
 986                        offset = 0;
 987                } else
 988                        offset += size;
 989                copy -= size;
 990                offset1 += size;
 991        }
 992
 993        if (len == offset1)
 994                return 0;
 995
 996        while (count--) {
 997                struct page *page[MAX_SKB_FRAGS];
 998                int num_pages;
 999                unsigned long base;
1000                unsigned long truesize;
1001
1002                len = from->iov_len - offset;
1003                if (!len) {
1004                        offset = 0;
1005                        ++from;
1006                        continue;
1007                }
1008                base = (unsigned long)from->iov_base + offset;
1009                size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
1010                if (i + size > MAX_SKB_FRAGS)
1011                        return -EMSGSIZE;
1012                num_pages = get_user_pages_fast(base, size, 0, &page[i]);
1013                if (num_pages != size) {
1014                        for (i = 0; i < num_pages; i++)
1015                                put_page(page[i]);
1016                        return -EFAULT;
1017                }
1018                truesize = size * PAGE_SIZE;
1019                skb->data_len += len;
1020                skb->len += len;
1021                skb->truesize += truesize;
1022                atomic_add(truesize, &skb->sk->sk_wmem_alloc);
1023                while (len) {
1024                        int off = base & ~PAGE_MASK;
1025                        int size = min_t(int, len, PAGE_SIZE - off);
1026                        __skb_fill_page_desc(skb, i, page[i], off, size);
1027                        skb_shinfo(skb)->nr_frags++;
1028                        /* increase sk_wmem_alloc */
1029                        base += size;
1030                        len -= size;
1031                        i++;
1032                }
1033                offset = 0;
1034                ++from;
1035        }
1036        return 0;
1037}
1038
1039/* Get packet from user space buffer */
1040static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1041                            void *msg_control, const struct iovec *iv,
1042                            size_t total_len, size_t count, int noblock)
1043{
1044        struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1045        struct sk_buff *skb;
1046        size_t len = total_len, align = NET_SKB_PAD;
1047        struct virtio_net_hdr gso = { 0 };
1048        int offset = 0;
1049        int copylen;
1050        bool zerocopy = false;
1051        int err;
1052        u32 rxhash;
1053
1054        if (!(tun->flags & TUN_NO_PI)) {
1055                if ((len -= sizeof(pi)) > total_len)
1056                        return -EINVAL;
1057
1058                if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
1059                        return -EFAULT;
1060                offset += sizeof(pi);
1061        }
1062
1063        if (tun->flags & TUN_VNET_HDR) {
1064                if ((len -= tun->vnet_hdr_sz) > total_len)
1065                        return -EINVAL;
1066
1067                if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
1068                        return -EFAULT;
1069
1070                if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1071                    gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
1072                        gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
1073
1074                if (gso.hdr_len > len)
1075                        return -EINVAL;
1076                offset += tun->vnet_hdr_sz;
1077        }
1078
1079        if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
1080                align += NET_IP_ALIGN;
1081                if (unlikely(len < ETH_HLEN ||
1082                             (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
1083                        return -EINVAL;
1084        }
1085
1086        if (msg_control)
1087                zerocopy = true;
1088
1089        if (zerocopy) {
1090                /* Userspace may produce vectors with count greater than
1091                 * MAX_SKB_FRAGS, so we need to linearize parts of the skb
1092                 * to let the rest of data to be fit in the frags.
1093                 */
1094                if (count > MAX_SKB_FRAGS) {
1095                        copylen = iov_length(iv, count - MAX_SKB_FRAGS);
1096                        if (copylen < offset)
1097                                copylen = 0;
1098                        else
1099                                copylen -= offset;
1100                } else
1101                                copylen = 0;
1102                /* There are 256 bytes to be copied in skb, so there is enough
1103                 * room for skb expand head in case it is used.
1104                 * The rest of the buffer is mapped from userspace.
1105                 */
1106                if (copylen < gso.hdr_len)
1107                        copylen = gso.hdr_len;
1108                if (!copylen)
1109                        copylen = GOODCOPY_LEN;
1110        } else
1111                copylen = len;
1112
1113        skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, noblock);
1114        if (IS_ERR(skb)) {
1115                if (PTR_ERR(skb) != -EAGAIN)
1116                        tun->dev->stats.rx_dropped++;
1117                return PTR_ERR(skb);
1118        }
1119
1120        if (zerocopy)
1121                err = zerocopy_sg_from_iovec(skb, iv, offset, count);
1122        else
1123                err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
1124
1125        if (err) {
1126                tun->dev->stats.rx_dropped++;
1127                kfree_skb(skb);
1128                return -EFAULT;
1129        }
1130
1131        if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1132                if (!skb_partial_csum_set(skb, gso.csum_start,
1133                                          gso.csum_offset)) {
1134                        tun->dev->stats.rx_frame_errors++;
1135                        kfree_skb(skb);
1136                        return -EINVAL;
1137                }
1138        }
1139
1140        switch (tun->flags & TUN_TYPE_MASK) {
1141        case TUN_TUN_DEV:
1142                if (tun->flags & TUN_NO_PI) {
1143                        switch (skb->data[0] & 0xf0) {
1144                        case 0x40:
1145                                pi.proto = htons(ETH_P_IP);
1146                                break;
1147                        case 0x60:
1148                                pi.proto = htons(ETH_P_IPV6);
1149                                break;
1150                        default:
1151                                tun->dev->stats.rx_dropped++;
1152                                kfree_skb(skb);
1153                                return -EINVAL;
1154                        }
1155                }
1156
1157                skb_reset_mac_header(skb);
1158                skb->protocol = pi.proto;
1159                skb->dev = tun->dev;
1160                break;
1161        case TUN_TAP_DEV:
1162                skb->protocol = eth_type_trans(skb, tun->dev);
1163                break;
1164        }
1165
1166        if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1167                pr_debug("GSO!\n");
1168                switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1169                case VIRTIO_NET_HDR_GSO_TCPV4:
1170                        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1171                        break;
1172                case VIRTIO_NET_HDR_GSO_TCPV6:
1173                        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1174                        break;
1175                case VIRTIO_NET_HDR_GSO_UDP:
1176                        skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1177                        break;
1178                default:
1179                        tun->dev->stats.rx_frame_errors++;
1180                        kfree_skb(skb);
1181                        return -EINVAL;
1182                }
1183
1184                if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1185                        skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1186
1187                skb_shinfo(skb)->gso_size = gso.gso_size;
1188                if (skb_shinfo(skb)->gso_size == 0) {
1189                        tun->dev->stats.rx_frame_errors++;
1190                        kfree_skb(skb);
1191                        return -EINVAL;
1192                }
1193
1194                /* Header must be checked, and gso_segs computed. */
1195                skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1196                skb_shinfo(skb)->gso_segs = 0;
1197        }
1198
1199        /* copy skb_ubuf_info for callback when skb has no error */
1200        if (zerocopy) {
1201                skb_shinfo(skb)->destructor_arg = msg_control;
1202                skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1203        }
1204
1205        skb_reset_network_header(skb);
1206        rxhash = skb_get_rxhash(skb);
1207        netif_rx_ni(skb);
1208
1209        tun->dev->stats.rx_packets++;
1210        tun->dev->stats.rx_bytes += len;
1211
1212        tun_flow_update(tun, rxhash, tfile);
1213        return total_len;
1214}
1215
1216static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
1217                              unsigned long count, loff_t pos)
1218{
1219        struct file *file = iocb->ki_filp;
1220        struct tun_struct *tun = tun_get(file);
1221        struct tun_file *tfile = file->private_data;
1222        ssize_t result;
1223
1224        if (!tun)
1225                return -EBADFD;
1226
1227        tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
1228
1229        result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count),
1230                              count, file->f_flags & O_NONBLOCK);
1231
1232        tun_put(tun);
1233        return result;
1234}
1235
1236/* Put packet to the user space buffer */
1237static ssize_t tun_put_user(struct tun_struct *tun,
1238                            struct tun_file *tfile,
1239                            struct sk_buff *skb,
1240                            const struct iovec *iv, int len)
1241{
1242        struct tun_pi pi = { 0, skb->protocol };
1243        ssize_t total = 0;
1244
1245        if (!(tun->flags & TUN_NO_PI)) {
1246                if ((len -= sizeof(pi)) < 0)
1247                        return -EINVAL;
1248
1249                if (len < skb->len) {
1250                        /* Packet will be striped */
1251                        pi.flags |= TUN_PKT_STRIP;
1252                }
1253
1254                if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
1255                        return -EFAULT;
1256                total += sizeof(pi);
1257        }
1258
1259        if (tun->flags & TUN_VNET_HDR) {
1260                struct virtio_net_hdr gso = { 0 }; /* no info leak */
1261                if ((len -= tun->vnet_hdr_sz) < 0)
1262                        return -EINVAL;
1263
1264                if (skb_is_gso(skb)) {
1265                        struct skb_shared_info *sinfo = skb_shinfo(skb);
1266
1267                        /* This is a hint as to how much should be linear. */
1268                        gso.hdr_len = skb_headlen(skb);
1269                        gso.gso_size = sinfo->gso_size;
1270                        if (sinfo->gso_type & SKB_GSO_TCPV4)
1271                                gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1272                        else if (sinfo->gso_type & SKB_GSO_TCPV6)
1273                                gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1274                        else if (sinfo->gso_type & SKB_GSO_UDP)
1275                                gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1276                        else {
1277                                pr_err("unexpected GSO type: "
1278                                       "0x%x, gso_size %d, hdr_len %d\n",
1279                                       sinfo->gso_type, gso.gso_size,
1280                                       gso.hdr_len);
1281                                print_hex_dump(KERN_ERR, "tun: ",
1282                                               DUMP_PREFIX_NONE,
1283                                               16, 1, skb->head,
1284                                               min((int)gso.hdr_len, 64), true);
1285                                WARN_ON_ONCE(1);
1286                                return -EINVAL;
1287                        }
1288                        if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1289                                gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1290                } else
1291                        gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1292
1293                if (skb->ip_summed == CHECKSUM_PARTIAL) {
1294                        gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1295                        gso.csum_start = skb_checksum_start_offset(skb);
1296                        gso.csum_offset = skb->csum_offset;
1297                } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1298                        gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1299                } /* else everything is zero */
1300
1301                if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
1302                                               sizeof(gso))))
1303                        return -EFAULT;
1304                total += tun->vnet_hdr_sz;
1305        }
1306
1307        len = min_t(int, skb->len, len);
1308
1309        skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
1310        total += skb->len;
1311
1312        tun->dev->stats.tx_packets++;
1313        tun->dev->stats.tx_bytes += len;
1314
1315        return total;
1316}
1317
1318static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1319                           struct kiocb *iocb, const struct iovec *iv,
1320                           ssize_t len, int noblock)
1321{
1322        DECLARE_WAITQUEUE(wait, current);
1323        struct sk_buff *skb;
1324        ssize_t ret = 0;
1325
1326        tun_debug(KERN_INFO, tun, "tun_do_read\n");
1327
1328        if (unlikely(!noblock))
1329                add_wait_queue(&tfile->wq.wait, &wait);
1330        while (len) {
1331                current->state = TASK_INTERRUPTIBLE;
1332
1333                /* Read frames from the queue */
1334                if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) {
1335                        if (noblock) {
1336                                ret = -EAGAIN;
1337                                break;
1338                        }
1339                        if (signal_pending(current)) {
1340                                ret = -ERESTARTSYS;
1341                                break;
1342                        }
1343                        if (tun->dev->reg_state != NETREG_REGISTERED) {
1344                                ret = -EIO;
1345                                break;
1346                        }
1347
1348                        /* Nothing to read, let's sleep */
1349                        schedule();
1350                        continue;
1351                }
1352
1353                ret = tun_put_user(tun, tfile, skb, iv, len);
1354                kfree_skb(skb);
1355                break;
1356        }
1357
1358        current->state = TASK_RUNNING;
1359        if (unlikely(!noblock))
1360                remove_wait_queue(&tfile->wq.wait, &wait);
1361
1362        return ret;
1363}
1364
1365static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1366                            unsigned long count, loff_t pos)
1367{
1368        struct file *file = iocb->ki_filp;
1369        struct tun_file *tfile = file->private_data;
1370        struct tun_struct *tun = __tun_get(tfile);
1371        ssize_t len, ret;
1372
1373        if (!tun)
1374                return -EBADFD;
1375        len = iov_length(iv, count);
1376        if (len < 0) {
1377                ret = -EINVAL;
1378                goto out;
1379        }
1380
1381        ret = tun_do_read(tun, tfile, iocb, iv, len,
1382                          file->f_flags & O_NONBLOCK);
1383        ret = min_t(ssize_t, ret, len);
1384out:
1385        tun_put(tun);
1386        return ret;
1387}
1388
1389static void tun_free_netdev(struct net_device *dev)
1390{
1391        struct tun_struct *tun = netdev_priv(dev);
1392
1393        BUG_ON(!(list_empty(&tun->disabled)));
1394        tun_flow_uninit(tun);
1395        security_tun_dev_free_security(tun->security);
1396        free_netdev(dev);
1397}
1398
1399static void tun_setup(struct net_device *dev)
1400{
1401        struct tun_struct *tun = netdev_priv(dev);
1402
1403        tun->owner = INVALID_UID;
1404        tun->group = INVALID_GID;
1405
1406        dev->ethtool_ops = &tun_ethtool_ops;
1407        dev->destructor = tun_free_netdev;
1408}
1409
1410/* Trivial set of netlink ops to allow deleting tun or tap
1411 * device with netlink.
1412 */
1413static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1414{
1415        return -EINVAL;
1416}
1417
1418static struct rtnl_link_ops tun_link_ops __read_mostly = {
1419        .kind           = DRV_NAME,
1420        .priv_size      = sizeof(struct tun_struct),
1421        .setup          = tun_setup,
1422        .validate       = tun_validate,
1423};
1424
1425static void tun_sock_write_space(struct sock *sk)
1426{
1427        struct tun_file *tfile;
1428        wait_queue_head_t *wqueue;
1429
1430        if (!sock_writeable(sk))
1431                return;
1432
1433        if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1434                return;
1435
1436        wqueue = sk_sleep(sk);
1437        if (wqueue && waitqueue_active(wqueue))
1438                wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1439                                                POLLWRNORM | POLLWRBAND);
1440
1441        tfile = container_of(sk, struct tun_file, sk);
1442        kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1443}
1444
1445static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1446                       struct msghdr *m, size_t total_len)
1447{
1448        int ret;
1449        struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1450        struct tun_struct *tun = __tun_get(tfile);
1451
1452        if (!tun)
1453                return -EBADFD;
1454        ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len,
1455                           m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1456        tun_put(tun);
1457        return ret;
1458}
1459
1460
1461static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1462                       struct msghdr *m, size_t total_len,
1463                       int flags)
1464{
1465        struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1466        struct tun_struct *tun = __tun_get(tfile);
1467        int ret;
1468
1469        if (!tun)
1470                return -EBADFD;
1471
1472        if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1473                return -EINVAL;
1474        ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len,
1475                          flags & MSG_DONTWAIT);
1476        if (ret > total_len) {
1477                m->msg_flags |= MSG_TRUNC;
1478                ret = flags & MSG_TRUNC ? ret : total_len;
1479        }
1480        tun_put(tun);
1481        return ret;
1482}
1483
1484static int tun_release(struct socket *sock)
1485{
1486        if (sock->sk)
1487                sock_put(sock->sk);
1488        return 0;
1489}
1490
1491/* Ops structure to mimic raw sockets with tun */
1492static const struct proto_ops tun_socket_ops = {
1493        .sendmsg = tun_sendmsg,
1494        .recvmsg = tun_recvmsg,
1495        .release = tun_release,
1496};
1497
1498static struct proto tun_proto = {
1499        .name           = "tun",
1500        .owner          = THIS_MODULE,
1501        .obj_size       = sizeof(struct tun_file),
1502};
1503
1504static int tun_flags(struct tun_struct *tun)
1505{
1506        int flags = 0;
1507
1508        if (tun->flags & TUN_TUN_DEV)
1509                flags |= IFF_TUN;
1510        else
1511                flags |= IFF_TAP;
1512
1513        if (tun->flags & TUN_NO_PI)
1514                flags |= IFF_NO_PI;
1515
1516        /* This flag has no real effect.  We track the value for backwards
1517         * compatibility.
1518         */
1519        if (tun->flags & TUN_ONE_QUEUE)
1520                flags |= IFF_ONE_QUEUE;
1521
1522        if (tun->flags & TUN_VNET_HDR)
1523                flags |= IFF_VNET_HDR;
1524
1525        if (tun->flags & TUN_TAP_MQ)
1526                flags |= IFF_MULTI_QUEUE;
1527
1528        return flags;
1529}
1530
1531static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1532                              char *buf)
1533{
1534        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1535        return sprintf(buf, "0x%x\n", tun_flags(tun));
1536}
1537
1538static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1539                              char *buf)
1540{
1541        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1542        return uid_valid(tun->owner)?
1543                sprintf(buf, "%u\n",
1544                        from_kuid_munged(current_user_ns(), tun->owner)):
1545                sprintf(buf, "-1\n");
1546}
1547
1548static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1549                              char *buf)
1550{
1551        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1552        return gid_valid(tun->group) ?
1553                sprintf(buf, "%u\n",
1554                        from_kgid_munged(current_user_ns(), tun->group)):
1555                sprintf(buf, "-1\n");
1556}
1557
1558static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1559static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1560static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1561
1562static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1563{
1564        struct tun_struct *tun;
1565        struct tun_file *tfile = file->private_data;
1566        struct net_device *dev;
1567        int err;
1568
1569        if (tfile->detached)
1570                return -EINVAL;
1571
1572        dev = __dev_get_by_name(net, ifr->ifr_name);
1573        if (dev) {
1574                if (ifr->ifr_flags & IFF_TUN_EXCL)
1575                        return -EBUSY;
1576                if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1577                        tun = netdev_priv(dev);
1578                else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1579                        tun = netdev_priv(dev);
1580                else
1581                        return -EINVAL;
1582
1583                if (tun_not_capable(tun))
1584                        return -EPERM;
1585                err = security_tun_dev_open(tun->security);
1586                if (err < 0)
1587                        return err;
1588
1589                err = tun_attach(tun, file);
1590                if (err < 0)
1591                        return err;
1592
1593                if (tun->flags & TUN_TAP_MQ &&
1594                    (tun->numqueues + tun->numdisabled > 1))
1595                        return err;
1596        }
1597        else {
1598                char *name;
1599                unsigned long flags = 0;
1600                int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1601                             MAX_TAP_QUEUES : 1;
1602
1603                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1604                        return -EPERM;
1605                err = security_tun_dev_create();
1606                if (err < 0)
1607                        return err;
1608
1609                /* Set dev type */
1610                if (ifr->ifr_flags & IFF_TUN) {
1611                        /* TUN device */
1612                        flags |= TUN_TUN_DEV;
1613                        name = "tun%d";
1614                } else if (ifr->ifr_flags & IFF_TAP) {
1615                        /* TAP device */
1616                        flags |= TUN_TAP_DEV;
1617                        name = "tap%d";
1618                } else
1619                        return -EINVAL;
1620
1621                if (*ifr->ifr_name)
1622                        name = ifr->ifr_name;
1623
1624                dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1625                                       tun_setup, queues, queues);
1626
1627                if (!dev)
1628                        return -ENOMEM;
1629
1630                dev_net_set(dev, net);
1631                dev->rtnl_link_ops = &tun_link_ops;
1632
1633                tun = netdev_priv(dev);
1634                tun->dev = dev;
1635                tun->flags = flags;
1636                tun->txflt.count = 0;
1637                tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1638
1639                tun->filter_attached = false;
1640                tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1641
1642                spin_lock_init(&tun->lock);
1643
1644                err = security_tun_dev_alloc_security(&tun->security);
1645                if (err < 0)
1646                        goto err_free_dev;
1647
1648                tun_net_init(dev);
1649
1650                err = tun_flow_init(tun);
1651                if (err < 0)
1652                        goto err_free_dev;
1653
1654                dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1655                        TUN_USER_FEATURES;
1656                dev->features = dev->hw_features;
1657
1658                INIT_LIST_HEAD(&tun->disabled);
1659                err = tun_attach(tun, file);
1660                if (err < 0)
1661                        goto err_free_dev;
1662
1663                err = register_netdevice(tun->dev);
1664                if (err < 0)
1665                        goto err_free_dev;
1666
1667                if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1668                    device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1669                    device_create_file(&tun->dev->dev, &dev_attr_group))
1670                        pr_err("Failed to create tun sysfs files\n");
1671        }
1672
1673        netif_carrier_on(tun->dev);
1674
1675        tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1676
1677        if (ifr->ifr_flags & IFF_NO_PI)
1678                tun->flags |= TUN_NO_PI;
1679        else
1680                tun->flags &= ~TUN_NO_PI;
1681
1682        /* This flag has no real effect.  We track the value for backwards
1683         * compatibility.
1684         */
1685        if (ifr->ifr_flags & IFF_ONE_QUEUE)
1686                tun->flags |= TUN_ONE_QUEUE;
1687        else
1688                tun->flags &= ~TUN_ONE_QUEUE;
1689
1690        if (ifr->ifr_flags & IFF_VNET_HDR)
1691                tun->flags |= TUN_VNET_HDR;
1692        else
1693                tun->flags &= ~TUN_VNET_HDR;
1694
1695        if (ifr->ifr_flags & IFF_MULTI_QUEUE)
1696                tun->flags |= TUN_TAP_MQ;
1697        else
1698                tun->flags &= ~TUN_TAP_MQ;
1699
1700        /* Make sure persistent devices do not get stuck in
1701         * xoff state.
1702         */
1703        if (netif_running(tun->dev))
1704                netif_tx_wake_all_queues(tun->dev);
1705
1706        strcpy(ifr->ifr_name, tun->dev->name);
1707        return 0;
1708
1709 err_free_dev:
1710        free_netdev(dev);
1711        return err;
1712}
1713
1714static void tun_get_iff(struct net *net, struct tun_struct *tun,
1715                       struct ifreq *ifr)
1716{
1717        tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1718
1719        strcpy(ifr->ifr_name, tun->dev->name);
1720
1721        ifr->ifr_flags = tun_flags(tun);
1722
1723}
1724
1725/* This is like a cut-down ethtool ops, except done via tun fd so no
1726 * privs required. */
1727static int set_offload(struct tun_struct *tun, unsigned long arg)
1728{
1729        netdev_features_t features = 0;
1730
1731        if (arg & TUN_F_CSUM) {
1732                features |= NETIF_F_HW_CSUM;
1733                arg &= ~TUN_F_CSUM;
1734
1735                if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1736                        if (arg & TUN_F_TSO_ECN) {
1737                                features |= NETIF_F_TSO_ECN;
1738                                arg &= ~TUN_F_TSO_ECN;
1739                        }
1740                        if (arg & TUN_F_TSO4)
1741                                features |= NETIF_F_TSO;
1742                        if (arg & TUN_F_TSO6)
1743                                features |= NETIF_F_TSO6;
1744                        arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1745                }
1746
1747                if (arg & TUN_F_UFO) {
1748                        features |= NETIF_F_UFO;
1749                        arg &= ~TUN_F_UFO;
1750                }
1751        }
1752
1753        /* This gives the user a way to test for new features in future by
1754         * trying to set them. */
1755        if (arg)
1756                return -EINVAL;
1757
1758        tun->set_features = features;
1759        netdev_update_features(tun->dev);
1760
1761        return 0;
1762}
1763
1764static void tun_detach_filter(struct tun_struct *tun, int n)
1765{
1766        int i;
1767        struct tun_file *tfile;
1768
1769        for (i = 0; i < n; i++) {
1770                tfile = rtnl_dereference(tun->tfiles[i]);
1771                sk_detach_filter(tfile->socket.sk);
1772        }
1773
1774        tun->filter_attached = false;
1775}
1776
1777static int tun_attach_filter(struct tun_struct *tun)
1778{
1779        int i, ret = 0;
1780        struct tun_file *tfile;
1781
1782        for (i = 0; i < tun->numqueues; i++) {
1783                tfile = rtnl_dereference(tun->tfiles[i]);
1784                ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1785                if (ret) {
1786                        tun_detach_filter(tun, i);
1787                        return ret;
1788                }
1789        }
1790
1791        tun->filter_attached = true;
1792        return ret;
1793}
1794
1795static void tun_set_sndbuf(struct tun_struct *tun)
1796{
1797        struct tun_file *tfile;
1798        int i;
1799
1800        for (i = 0; i < tun->numqueues; i++) {
1801                tfile = rtnl_dereference(tun->tfiles[i]);
1802                tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1803        }
1804}
1805
1806static int tun_set_queue(struct file *file, struct ifreq *ifr)
1807{
1808        struct tun_file *tfile = file->private_data;
1809        struct tun_struct *tun;
1810        int ret = 0;
1811
1812        rtnl_lock();
1813
1814        if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1815                tun = tfile->detached;
1816                if (!tun) {
1817                        ret = -EINVAL;
1818                        goto unlock;
1819                }
1820                ret = security_tun_dev_attach_queue(tun->security);
1821                if (ret < 0)
1822                        goto unlock;
1823                ret = tun_attach(tun, file);
1824        } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1825                tun = rtnl_dereference(tfile->tun);
1826                if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached)
1827                        ret = -EINVAL;
1828                else
1829                        __tun_detach(tfile, false);
1830        } else
1831                ret = -EINVAL;
1832
1833unlock:
1834        rtnl_unlock();
1835        return ret;
1836}
1837
1838static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1839                            unsigned long arg, int ifreq_len)
1840{
1841        struct tun_file *tfile = file->private_data;
1842        struct tun_struct *tun;
1843        void __user* argp = (void __user*)arg;
1844        struct ifreq ifr;
1845        kuid_t owner;
1846        kgid_t group;
1847        int sndbuf;
1848        int vnet_hdr_sz;
1849        int ret;
1850
1851        if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1852                if (copy_from_user(&ifr, argp, ifreq_len))
1853                        return -EFAULT;
1854        } else {
1855                memset(&ifr, 0, sizeof(ifr));
1856        }
1857        if (cmd == TUNGETFEATURES) {
1858                /* Currently this just means: "what IFF flags are valid?".
1859                 * This is needed because we never checked for invalid flags on
1860                 * TUNSETIFF. */
1861                return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1862                                IFF_VNET_HDR | IFF_MULTI_QUEUE,
1863                                (unsigned int __user*)argp);
1864        } else if (cmd == TUNSETQUEUE)
1865                return tun_set_queue(file, &ifr);
1866
1867        ret = 0;
1868        rtnl_lock();
1869
1870        tun = __tun_get(tfile);
1871        if (cmd == TUNSETIFF && !tun) {
1872                ifr.ifr_name[IFNAMSIZ-1] = '\0';
1873
1874                ret = tun_set_iff(tfile->net, file, &ifr);
1875
1876                if (ret)
1877                        goto unlock;
1878
1879                if (copy_to_user(argp, &ifr, ifreq_len))
1880                        ret = -EFAULT;
1881                goto unlock;
1882        }
1883
1884        ret = -EBADFD;
1885        if (!tun)
1886                goto unlock;
1887
1888        tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1889
1890        ret = 0;
1891        switch (cmd) {
1892        case TUNGETIFF:
1893                tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1894
1895                if (copy_to_user(argp, &ifr, ifreq_len))
1896                        ret = -EFAULT;
1897                break;
1898
1899        case TUNSETNOCSUM:
1900                /* Disable/Enable checksum */
1901
1902                /* [unimplemented] */
1903                tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1904                          arg ? "disabled" : "enabled");
1905                break;
1906
1907        case TUNSETPERSIST:
1908                /* Disable/Enable persist mode. Keep an extra reference to the
1909                 * module to prevent the module being unprobed.
1910                 */
1911                if (arg && !(tun->flags & TUN_PERSIST)) {
1912                        tun->flags |= TUN_PERSIST;
1913                        __module_get(THIS_MODULE);
1914                }
1915                if (!arg && (tun->flags & TUN_PERSIST)) {
1916                        tun->flags &= ~TUN_PERSIST;
1917                        module_put(THIS_MODULE);
1918                }
1919
1920                tun_debug(KERN_INFO, tun, "persist %s\n",
1921                          arg ? "enabled" : "disabled");
1922                break;
1923
1924        case TUNSETOWNER:
1925                /* Set owner of the device */
1926                owner = make_kuid(current_user_ns(), arg);
1927                if (!uid_valid(owner)) {
1928                        ret = -EINVAL;
1929                        break;
1930                }
1931                tun->owner = owner;
1932                tun_debug(KERN_INFO, tun, "owner set to %u\n",
1933                          from_kuid(&init_user_ns, tun->owner));
1934                break;
1935
1936        case TUNSETGROUP:
1937                /* Set group of the device */
1938                group = make_kgid(current_user_ns(), arg);
1939                if (!gid_valid(group)) {
1940                        ret = -EINVAL;
1941                        break;
1942                }
1943                tun->group = group;
1944                tun_debug(KERN_INFO, tun, "group set to %u\n",
1945                          from_kgid(&init_user_ns, tun->group));
1946                break;
1947
1948        case TUNSETLINK:
1949                /* Only allow setting the type when the interface is down */
1950                if (tun->dev->flags & IFF_UP) {
1951                        tun_debug(KERN_INFO, tun,
1952                                  "Linktype set failed because interface is up\n");
1953                        ret = -EBUSY;
1954                } else {
1955                        tun->dev->type = (int) arg;
1956                        tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1957                                  tun->dev->type);
1958                        ret = 0;
1959                }
1960                break;
1961
1962#ifdef TUN_DEBUG
1963        case TUNSETDEBUG:
1964                tun->debug = arg;
1965                break;
1966#endif
1967        case TUNSETOFFLOAD:
1968                ret = set_offload(tun, arg);
1969                break;
1970
1971        case TUNSETTXFILTER:
1972                /* Can be set only for TAPs */
1973                ret = -EINVAL;
1974                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1975                        break;
1976                ret = update_filter(&tun->txflt, (void __user *)arg);
1977                break;
1978
1979        case SIOCGIFHWADDR:
1980                /* Get hw address */
1981                memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1982                ifr.ifr_hwaddr.sa_family = tun->dev->type;
1983                if (copy_to_user(argp, &ifr, ifreq_len))
1984                        ret = -EFAULT;
1985                break;
1986
1987        case SIOCSIFHWADDR:
1988                /* Set hw address */
1989                tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1990                          ifr.ifr_hwaddr.sa_data);
1991
1992                ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1993                break;
1994
1995        case TUNGETSNDBUF:
1996                sndbuf = tfile->socket.sk->sk_sndbuf;
1997                if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1998                        ret = -EFAULT;
1999                break;
2000
2001        case TUNSETSNDBUF:
2002                if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2003                        ret = -EFAULT;
2004                        break;
2005                }
2006
2007                tun->sndbuf = sndbuf;
2008                tun_set_sndbuf(tun);
2009                break;
2010
2011        case TUNGETVNETHDRSZ:
2012                vnet_hdr_sz = tun->vnet_hdr_sz;
2013                if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2014                        ret = -EFAULT;
2015                break;
2016
2017        case TUNSETVNETHDRSZ:
2018                if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2019                        ret = -EFAULT;
2020                        break;
2021                }
2022                if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2023                        ret = -EINVAL;
2024                        break;
2025                }
2026
2027                tun->vnet_hdr_sz = vnet_hdr_sz;
2028                break;
2029
2030        case TUNATTACHFILTER:
2031                /* Can be set only for TAPs */
2032                ret = -EINVAL;
2033                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2034                        break;
2035                ret = -EFAULT;
2036                if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2037                        break;
2038
2039                ret = tun_attach_filter(tun);
2040                break;
2041
2042        case TUNDETACHFILTER:
2043                /* Can be set only for TAPs */
2044                ret = -EINVAL;
2045                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2046                        break;
2047                ret = 0;
2048                tun_detach_filter(tun, tun->numqueues);
2049                break;
2050
2051        default:
2052                ret = -EINVAL;
2053                break;
2054        }
2055
2056unlock:
2057        rtnl_unlock();
2058        if (tun)
2059                tun_put(tun);
2060        return ret;
2061}
2062
2063static long tun_chr_ioctl(struct file *file,
2064                          unsigned int cmd, unsigned long arg)
2065{
2066        return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2067}
2068
2069#ifdef CONFIG_COMPAT
2070static long tun_chr_compat_ioctl(struct file *file,
2071                         unsigned int cmd, unsigned long arg)
2072{
2073        switch (cmd) {
2074        case TUNSETIFF:
2075        case TUNGETIFF:
2076        case TUNSETTXFILTER:
2077        case TUNGETSNDBUF:
2078        case TUNSETSNDBUF:
2079        case SIOCGIFHWADDR:
2080        case SIOCSIFHWADDR:
2081                arg = (unsigned long)compat_ptr(arg);
2082                break;
2083        default:
2084                arg = (compat_ulong_t)arg;
2085                break;
2086        }
2087
2088        /*
2089         * compat_ifreq is shorter than ifreq, so we must not access beyond
2090         * the end of that structure. All fields that are used in this
2091         * driver are compatible though, we don't need to convert the
2092         * contents.
2093         */
2094        return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2095}
2096#endif /* CONFIG_COMPAT */
2097
2098static int tun_chr_fasync(int fd, struct file *file, int on)
2099{
2100        struct tun_file *tfile = file->private_data;
2101        int ret;
2102
2103        if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2104                goto out;
2105
2106        if (on) {
2107                ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2108                if (ret)
2109                        goto out;
2110                tfile->flags |= TUN_FASYNC;
2111        } else
2112                tfile->flags &= ~TUN_FASYNC;
2113        ret = 0;
2114out:
2115        return ret;
2116}
2117
2118static int tun_chr_open(struct inode *inode, struct file * file)
2119{
2120        struct tun_file *tfile;
2121
2122        DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2123
2124        tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
2125                                            &tun_proto);
2126        if (!tfile)
2127                return -ENOMEM;
2128        rcu_assign_pointer(tfile->tun, NULL);
2129        tfile->net = get_net(current->nsproxy->net_ns);
2130        tfile->flags = 0;
2131
2132        rcu_assign_pointer(tfile->socket.wq, &tfile->wq);
2133        init_waitqueue_head(&tfile->wq.wait);
2134
2135        tfile->socket.file = file;
2136        tfile->socket.ops = &tun_socket_ops;
2137
2138        sock_init_data(&tfile->socket, &tfile->sk);
2139        sk_change_net(&tfile->sk, tfile->net);
2140
2141        tfile->sk.sk_write_space = tun_sock_write_space;
2142        tfile->sk.sk_sndbuf = INT_MAX;
2143
2144        file->private_data = tfile;
2145        set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
2146        INIT_LIST_HEAD(&tfile->next);
2147
2148        return 0;
2149}
2150
2151static int tun_chr_close(struct inode *inode, struct file *file)
2152{
2153        struct tun_file *tfile = file->private_data;
2154        struct net *net = tfile->net;
2155
2156        tun_detach(tfile, true);
2157        put_net(net);
2158
2159        return 0;
2160}
2161
2162static const struct file_operations tun_fops = {
2163        .owner  = THIS_MODULE,
2164        .llseek = no_llseek,
2165        .read  = do_sync_read,
2166        .aio_read  = tun_chr_aio_read,
2167        .write = do_sync_write,
2168        .aio_write = tun_chr_aio_write,
2169        .poll   = tun_chr_poll,
2170        .unlocked_ioctl = tun_chr_ioctl,
2171#ifdef CONFIG_COMPAT
2172        .compat_ioctl = tun_chr_compat_ioctl,
2173#endif
2174        .open   = tun_chr_open,
2175        .release = tun_chr_close,
2176        .fasync = tun_chr_fasync
2177};
2178
2179static struct miscdevice tun_miscdev = {
2180        .minor = TUN_MINOR,
2181        .name = "tun",
2182        .nodename = "net/tun",
2183        .fops = &tun_fops,
2184};
2185
2186/* ethtool interface */
2187
2188static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2189{
2190        cmd->supported          = 0;
2191        cmd->advertising        = 0;
2192        ethtool_cmd_speed_set(cmd, SPEED_10);
2193        cmd->duplex             = DUPLEX_FULL;
2194        cmd->port               = PORT_TP;
2195        cmd->phy_address        = 0;
2196        cmd->transceiver        = XCVR_INTERNAL;
2197        cmd->autoneg            = AUTONEG_DISABLE;
2198        cmd->maxtxpkt           = 0;
2199        cmd->maxrxpkt           = 0;
2200        return 0;
2201}
2202
2203static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2204{
2205        struct tun_struct *tun = netdev_priv(dev);
2206
2207        strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2208        strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2209
2210        switch (tun->flags & TUN_TYPE_MASK) {
2211        case TUN_TUN_DEV:
2212                strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2213                break;
2214        case TUN_TAP_DEV:
2215                strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2216                break;
2217        }
2218}
2219
2220static u32 tun_get_msglevel(struct net_device *dev)
2221{
2222#ifdef TUN_DEBUG
2223        struct tun_struct *tun = netdev_priv(dev);
2224        return tun->debug;
2225#else
2226        return -EOPNOTSUPP;
2227#endif
2228}
2229
2230static void tun_set_msglevel(struct net_device *dev, u32 value)
2231{
2232#ifdef TUN_DEBUG
2233        struct tun_struct *tun = netdev_priv(dev);
2234        tun->debug = value;
2235#endif
2236}
2237
2238static const struct ethtool_ops tun_ethtool_ops = {
2239        .get_settings   = tun_get_settings,
2240        .get_drvinfo    = tun_get_drvinfo,
2241        .get_msglevel   = tun_get_msglevel,
2242        .set_msglevel   = tun_set_msglevel,
2243        .get_link       = ethtool_op_get_link,
2244};
2245
2246
2247static int __init tun_init(void)
2248{
2249        int ret = 0;
2250
2251        pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2252        pr_info("%s\n", DRV_COPYRIGHT);
2253
2254        ret = rtnl_link_register(&tun_link_ops);
2255        if (ret) {
2256                pr_err("Can't register link_ops\n");
2257                goto err_linkops;
2258        }
2259
2260        ret = misc_register(&tun_miscdev);
2261        if (ret) {
2262                pr_err("Can't register misc device %d\n", TUN_MINOR);
2263                goto err_misc;
2264        }
2265        return  0;
2266err_misc:
2267        rtnl_link_unregister(&tun_link_ops);
2268err_linkops:
2269        return ret;
2270}
2271
2272static void tun_cleanup(void)
2273{
2274        misc_deregister(&tun_miscdev);
2275        rtnl_link_unregister(&tun_link_ops);
2276}
2277
2278/* Get an underlying socket object from tun file.  Returns error unless file is
2279 * attached to a device.  The returned object works like a packet socket, it
2280 * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2281 * holding a reference to the file for as long as the socket is in use. */
2282struct socket *tun_get_socket(struct file *file)
2283{
2284        struct tun_file *tfile;
2285        if (file->f_op != &tun_fops)
2286                return ERR_PTR(-EINVAL);
2287        tfile = file->private_data;
2288        if (!tfile)
2289                return ERR_PTR(-EBADFD);
2290        return &tfile->socket;
2291}
2292EXPORT_SYMBOL_GPL(tun_get_socket);
2293
2294module_init(tun_init);
2295module_exit(tun_cleanup);
2296MODULE_DESCRIPTION(DRV_DESCRIPTION);
2297MODULE_AUTHOR(DRV_COPYRIGHT);
2298MODULE_LICENSE("GPL");
2299MODULE_ALIAS_MISCDEV(TUN_MINOR);
2300MODULE_ALIAS("devname:net/tun");
2301
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