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
 201        hlist_for_each_entry_rcu(e, head, hash_link) {
 202                if (e->rxhash == rxhash)
 203                        return e;
 204        }
 205        return NULL;
 206}
 207
 208static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 209                                              struct hlist_head *head,
 210                                              u32 rxhash, u16 queue_index)
 211{
 212        struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 213
 214        if (e) {
 215                tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 216                          rxhash, queue_index);
 217                e->updated = jiffies;
 218                e->rxhash = rxhash;
 219                e->queue_index = queue_index;
 220                e->tun = tun;
 221                hlist_add_head_rcu(&e->hash_link, head);
 222                ++tun->flow_count;
 223        }
 224        return e;
 225}
 226
 227static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 228{
 229        tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 230                  e->rxhash, e->queue_index);
 231        hlist_del_rcu(&e->hash_link);
 232        kfree_rcu(e, rcu);
 233        --tun->flow_count;
 234}
 235
 236static void tun_flow_flush(struct tun_struct *tun)
 237{
 238        int i;
 239
 240        spin_lock_bh(&tun->lock);
 241        for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 242                struct tun_flow_entry *e;
 243                struct hlist_node *n;
 244
 245                hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 246                        tun_flow_delete(tun, e);
 247        }
 248        spin_unlock_bh(&tun->lock);
 249}
 250
 251static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 252{
 253        int i;
 254
 255        spin_lock_bh(&tun->lock);
 256        for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 257                struct tun_flow_entry *e;
 258                struct hlist_node *n;
 259
 260                hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 261                        if (e->queue_index == queue_index)
 262                                tun_flow_delete(tun, e);
 263                }
 264        }
 265        spin_unlock_bh(&tun->lock);
 266}
 267
 268static void tun_flow_cleanup(unsigned long data)
 269{
 270        struct tun_struct *tun = (struct tun_struct *)data;
 271        unsigned long delay = tun->ageing_time;
 272        unsigned long next_timer = jiffies + delay;
 273        unsigned long count = 0;
 274        int i;
 275
 276        tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 277
 278        spin_lock_bh(&tun->lock);
 279        for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 280                struct tun_flow_entry *e;
 281                struct hlist_node *n;
 282
 283                hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 284                        unsigned long this_timer;
 285                        count++;
 286                        this_timer = e->updated + delay;
 287                        if (time_before_eq(this_timer, jiffies))
 288                                tun_flow_delete(tun, e);
 289                        else if (time_before(this_timer, next_timer))
 290                                next_timer = this_timer;
 291                }
 292        }
 293
 294        if (count)
 295                mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 296        spin_unlock_bh(&tun->lock);
 297}
 298
 299static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 300                            struct tun_file *tfile)
 301{
 302        struct hlist_head *head;
 303        struct tun_flow_entry *e;
 304        unsigned long delay = tun->ageing_time;
 305        u16 queue_index = tfile->queue_index;
 306
 307        if (!rxhash)
 308                return;
 309        else
 310                head = &tun->flows[tun_hashfn(rxhash)];
 311
 312        rcu_read_lock();
 313
 314        /* We may get a very small possibility of OOO during switching, not
 315         * worth to optimize.*/
 316        if (tun->numqueues == 1 || tfile->detached)
 317                goto unlock;
 318
 319        e = tun_flow_find(head, rxhash);
 320        if (likely(e)) {
 321                /* TODO: keep queueing to old queue until it's empty? */
 322                e->queue_index = queue_index;
 323                e->updated = jiffies;
 324        } else {
 325                spin_lock_bh(&tun->lock);
 326                if (!tun_flow_find(head, rxhash) &&
 327                    tun->flow_count < MAX_TAP_FLOWS)
 328                        tun_flow_create(tun, head, rxhash, queue_index);
 329
 330                if (!timer_pending(&tun->flow_gc_timer))
 331                        mod_timer(&tun->flow_gc_timer,
 332                                  round_jiffies_up(jiffies + delay));
 333                spin_unlock_bh(&tun->lock);
 334        }
 335
 336unlock:
 337        rcu_read_unlock();
 338}
 339
 340/* We try to identify a flow through its rxhash first. The reason that
 341 * we do not check rxq no. is becuase some cards(e.g 82599), chooses
 342 * the rxq based on the txq where the last packet of the flow comes. As
 343 * the userspace application move between processors, we may get a
 344 * different rxq no. here. If we could not get rxhash, then we would
 345 * hope the rxq no. may help here.
 346 */
 347static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb)
 348{
 349        struct tun_struct *tun = netdev_priv(dev);
 350        struct tun_flow_entry *e;
 351        u32 txq = 0;
 352        u32 numqueues = 0;
 353
 354        rcu_read_lock();
 355        numqueues = ACCESS_ONCE(tun->numqueues);
 356
 357        txq = skb_get_rxhash(skb);
 358        if (txq) {
 359                e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 360                if (e)
 361                        txq = e->queue_index;
 362                else
 363                        /* use multiply and shift instead of expensive divide */
 364                        txq = ((u64)txq * numqueues) >> 32;
 365        } else if (likely(skb_rx_queue_recorded(skb))) {
 366                txq = skb_get_rx_queue(skb);
 367                while (unlikely(txq >= numqueues))
 368                        txq -= numqueues;
 369        }
 370
 371        rcu_read_unlock();
 372        return txq;
 373}
 374
 375static inline bool tun_not_capable(struct tun_struct *tun)
 376{
 377        const struct cred *cred = current_cred();
 378        struct net *net = dev_net(tun->dev);
 379
 380        return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 381                  (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 382                !ns_capable(net->user_ns, CAP_NET_ADMIN);
 383}
 384
 385static void tun_set_real_num_queues(struct tun_struct *tun)
 386{
 387        netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 388        netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 389}
 390
 391static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 392{
 393        tfile->detached = tun;
 394        list_add_tail(&tfile->next, &tun->disabled);
 395        ++tun->numdisabled;
 396}
 397
 398static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 399{
 400        struct tun_struct *tun = tfile->detached;
 401
 402        tfile->detached = NULL;
 403        list_del_init(&tfile->next);
 404        --tun->numdisabled;
 405        return tun;
 406}
 407
 408static void __tun_detach(struct tun_file *tfile, bool clean)
 409{
 410        struct tun_file *ntfile;
 411        struct tun_struct *tun;
 412
 413        tun = rtnl_dereference(tfile->tun);
 414
 415        if (tun && !tfile->detached) {
 416                u16 index = tfile->queue_index;
 417                BUG_ON(index >= tun->numqueues);
 418
 419                rcu_assign_pointer(tun->tfiles[index],
 420                                   tun->tfiles[tun->numqueues - 1]);
 421                ntfile = rtnl_dereference(tun->tfiles[index]);
 422                ntfile->queue_index = index;
 423
 424                --tun->numqueues;
 425                if (clean) {
 426                        rcu_assign_pointer(tfile->tun, NULL);
 427                        sock_put(&tfile->sk);
 428                } else
 429                        tun_disable_queue(tun, tfile);
 430
 431                synchronize_net();
 432                tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 433                /* Drop read queue */
 434                skb_queue_purge(&tfile->sk.sk_receive_queue);
 435                tun_set_real_num_queues(tun);
 436        } else if (tfile->detached && clean) {
 437                tun = tun_enable_queue(tfile);
 438                sock_put(&tfile->sk);
 439        }
 440
 441        if (clean) {
 442                if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 443                        netif_carrier_off(tun->dev);
 444
 445                        if (!(tun->flags & TUN_PERSIST) &&
 446                            tun->dev->reg_state == NETREG_REGISTERED)
 447                                unregister_netdevice(tun->dev);
 448                }
 449
 450                BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
 451                                 &tfile->socket.flags));
 452                sk_release_kernel(&tfile->sk);
 453        }
 454}
 455
 456static void tun_detach(struct tun_file *tfile, bool clean)
 457{
 458        rtnl_lock();
 459        __tun_detach(tfile, clean);
 460        rtnl_unlock();
 461}
 462
 463static void tun_detach_all(struct net_device *dev)
 464{
 465        struct tun_struct *tun = netdev_priv(dev);
 466        struct tun_file *tfile, *tmp;
 467        int i, n = tun->numqueues;
 468
 469        for (i = 0; i < n; i++) {
 470                tfile = rtnl_dereference(tun->tfiles[i]);
 471                BUG_ON(!tfile);
 472                wake_up_all(&tfile->wq.wait);
 473                rcu_assign_pointer(tfile->tun, NULL);
 474                --tun->numqueues;
 475        }
 476        list_for_each_entry(tfile, &tun->disabled, next) {
 477                wake_up_all(&tfile->wq.wait);
 478                rcu_assign_pointer(tfile->tun, NULL);
 479        }
 480        BUG_ON(tun->numqueues != 0);
 481
 482        synchronize_net();
 483        for (i = 0; i < n; i++) {
 484                tfile = rtnl_dereference(tun->tfiles[i]);
 485                /* Drop read queue */
 486                skb_queue_purge(&tfile->sk.sk_receive_queue);
 487                sock_put(&tfile->sk);
 488        }
 489        list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 490                tun_enable_queue(tfile);
 491                skb_queue_purge(&tfile->sk.sk_receive_queue);
 492                sock_put(&tfile->sk);
 493        }
 494        BUG_ON(tun->numdisabled != 0);
 495
 496        if (tun->flags & TUN_PERSIST)
 497                module_put(THIS_MODULE);
 498}
 499
 500static int tun_attach(struct tun_struct *tun, struct file *file)
 501{
 502        struct tun_file *tfile = file->private_data;
 503        int err;
 504
 505        err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 506        if (err < 0)
 507                goto out;
 508
 509        err = -EINVAL;
 510        if (rtnl_dereference(tfile->tun) && !tfile->detached)
 511                goto out;
 512
 513        err = -EBUSY;
 514        if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1)
 515                goto out;
 516
 517        err = -E2BIG;
 518        if (!tfile->detached &&
 519            tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 520                goto out;
 521
 522        err = 0;
 523
 524        /* Re-attach the filter to presist device */
 525        if (tun->filter_attached == true) {
 526                err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 527                if (!err)
 528                        goto out;
 529        }
 530        tfile->queue_index = tun->numqueues;
 531        rcu_assign_pointer(tfile->tun, tun);
 532        rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 533        tun->numqueues++;
 534
 535        if (tfile->detached)
 536                tun_enable_queue(tfile);
 537        else
 538                sock_hold(&tfile->sk);
 539
 540        tun_set_real_num_queues(tun);
 541
 542        /* device is allowed to go away first, so no need to hold extra
 543         * refcnt.
 544         */
 545
 546out:
 547        return err;
 548}
 549
 550static struct tun_struct *__tun_get(struct tun_file *tfile)
 551{
 552        struct tun_struct *tun;
 553
 554        rcu_read_lock();
 555        tun = rcu_dereference(tfile->tun);
 556        if (tun)
 557                dev_hold(tun->dev);
 558        rcu_read_unlock();
 559
 560        return tun;
 561}
 562
 563static struct tun_struct *tun_get(struct file *file)
 564{
 565        return __tun_get(file->private_data);
 566}
 567
 568static void tun_put(struct tun_struct *tun)
 569{
 570        dev_put(tun->dev);
 571}
 572
 573/* TAP filtering */
 574static void addr_hash_set(u32 *mask, const u8 *addr)
 575{
 576        int n = ether_crc(ETH_ALEN, addr) >> 26;
 577        mask[n >> 5] |= (1 << (n & 31));
 578}
 579
 580static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 581{
 582        int n = ether_crc(ETH_ALEN, addr) >> 26;
 583        return mask[n >> 5] & (1 << (n & 31));
 584}
 585
 586static int update_filter(struct tap_filter *filter, void __user *arg)
 587{
 588        struct { u8 u[ETH_ALEN]; } *addr;
 589        struct tun_filter uf;
 590        int err, alen, n, nexact;
 591
 592        if (copy_from_user(&uf, arg, sizeof(uf)))
 593                return -EFAULT;
 594
 595        if (!uf.count) {
 596                /* Disabled */
 597                filter->count = 0;
 598                return 0;
 599        }
 600
 601        alen = ETH_ALEN * uf.count;
 602        addr = kmalloc(alen, GFP_KERNEL);
 603        if (!addr)
 604                return -ENOMEM;
 605
 606        if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 607                err = -EFAULT;
 608                goto done;
 609        }
 610
 611        /* The filter is updated without holding any locks. Which is
 612         * perfectly safe. We disable it first and in the worst
 613         * case we'll accept a few undesired packets. */
 614        filter->count = 0;
 615        wmb();
 616
 617        /* Use first set of addresses as an exact filter */
 618        for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 619                memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 620
 621        nexact = n;
 622
 623        /* Remaining multicast addresses are hashed,
 624         * unicast will leave the filter disabled. */
 625        memset(filter->mask, 0, sizeof(filter->mask));
 626        for (; n < uf.count; n++) {
 627                if (!is_multicast_ether_addr(addr[n].u)) {
 628                        err = 0; /* no filter */
 629                        goto done;
 630                }
 631                addr_hash_set(filter->mask, addr[n].u);
 632        }
 633
 634        /* For ALLMULTI just set the mask to all ones.
 635         * This overrides the mask populated above. */
 636        if ((uf.flags & TUN_FLT_ALLMULTI))
 637                memset(filter->mask, ~0, sizeof(filter->mask));
 638
 639        /* Now enable the filter */
 640        wmb();
 641        filter->count = nexact;
 642
 643        /* Return the number of exact filters */
 644        err = nexact;
 645
 646done:
 647        kfree(addr);
 648        return err;
 649}
 650
 651/* Returns: 0 - drop, !=0 - accept */
 652static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 653{
 654        /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 655         * at this point. */
 656        struct ethhdr *eh = (struct ethhdr *) skb->data;
 657        int i;
 658
 659        /* Exact match */
 660        for (i = 0; i < filter->count; i++)
 661                if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 662                        return 1;
 663
 664        /* Inexact match (multicast only) */
 665        if (is_multicast_ether_addr(eh->h_dest))
 666                return addr_hash_test(filter->mask, eh->h_dest);
 667
 668        return 0;
 669}
 670
 671/*
 672 * Checks whether the packet is accepted or not.
 673 * Returns: 0 - drop, !=0 - accept
 674 */
 675static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 676{
 677        if (!filter->count)
 678                return 1;
 679
 680        return run_filter(filter, skb);
 681}
 682
 683/* Network device part of the driver */
 684
 685static const struct ethtool_ops tun_ethtool_ops;
 686
 687/* Net device detach from fd. */
 688static void tun_net_uninit(struct net_device *dev)
 689{
 690        tun_detach_all(dev);
 691}
 692
 693/* Net device open. */
 694static int tun_net_open(struct net_device *dev)
 695{
 696        netif_tx_start_all_queues(dev);
 697        return 0;
 698}
 699
 700/* Net device close. */
 701static int tun_net_close(struct net_device *dev)
 702{
 703        netif_tx_stop_all_queues(dev);
 704        return 0;
 705}
 706
 707/* Net device start xmit */
 708static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 709{
 710        struct tun_struct *tun = netdev_priv(dev);
 711        int txq = skb->queue_mapping;
 712        struct tun_file *tfile;
 713
 714        rcu_read_lock();
 715        tfile = rcu_dereference(tun->tfiles[txq]);
 716
 717        /* Drop packet if interface is not attached */
 718        if (txq >= tun->numqueues)
 719                goto drop;
 720
 721        tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 722
 723        BUG_ON(!tfile);
 724
 725        /* Drop if the filter does not like it.
 726         * This is a noop if the filter is disabled.
 727         * Filter can be enabled only for the TAP devices. */
 728        if (!check_filter(&tun->txflt, skb))
 729                goto drop;
 730
 731        if (tfile->socket.sk->sk_filter &&
 732            sk_filter(tfile->socket.sk, skb))
 733                goto drop;
 734
 735        /* Limit the number of packets queued by dividing txq length with the
 736         * number of queues.
 737         */
 738        if (skb_queue_len(&tfile->socket.sk->sk_receive_queue)
 739                          >= dev->tx_queue_len / tun->numqueues)
 740                goto drop;
 741
 742        /* Orphan the skb - required as we might hang on to it
 743         * for indefinite time. */
 744        if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 745                goto drop;
 746        skb_orphan(skb);
 747
 748        nf_reset(skb);
 749
 750        /* Enqueue packet */
 751        skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
 752
 753        /* Notify and wake up reader process */
 754        if (tfile->flags & TUN_FASYNC)
 755                kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
 756        wake_up_interruptible_poll(&tfile->wq.wait, POLLIN |
 757                                   POLLRDNORM | POLLRDBAND);
 758
 759        rcu_read_unlock();
 760        return NETDEV_TX_OK;
 761
 762drop:
 763        dev->stats.tx_dropped++;
 764        skb_tx_error(skb);
 765        kfree_skb(skb);
 766        rcu_read_unlock();
 767        return NETDEV_TX_OK;
 768}
 769
 770static void tun_net_mclist(struct net_device *dev)
 771{
 772        /*
 773         * This callback is supposed to deal with mc filter in
 774         * _rx_ path and has nothing to do with the _tx_ path.
 775         * In rx path we always accept everything userspace gives us.
 776         */
 777}
 778
 779#define MIN_MTU 68
 780#define MAX_MTU 65535
 781
 782static int
 783tun_net_change_mtu(struct net_device *dev, int new_mtu)
 784{
 785        if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 786                return -EINVAL;
 787        dev->mtu = new_mtu;
 788        return 0;
 789}
 790
 791static netdev_features_t tun_net_fix_features(struct net_device *dev,
 792        netdev_features_t features)
 793{
 794        struct tun_struct *tun = netdev_priv(dev);
 795
 796        return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 797}
 798#ifdef CONFIG_NET_POLL_CONTROLLER
 799static void tun_poll_controller(struct net_device *dev)
 800{
 801        /*
 802         * Tun only receives frames when:
 803         * 1) the char device endpoint gets data from user space
 804         * 2) the tun socket gets a sendmsg call from user space
 805         * Since both of those are syncronous operations, we are guaranteed
 806         * never to have pending data when we poll for it
 807         * so theres nothing to do here but return.
 808         * We need this though so netpoll recognizes us as an interface that
 809         * supports polling, which enables bridge devices in virt setups to
 810         * still use netconsole
 811         */
 812        return;
 813}
 814#endif
 815static const struct net_device_ops tun_netdev_ops = {
 816        .ndo_uninit             = tun_net_uninit,
 817        .ndo_open               = tun_net_open,
 818        .ndo_stop               = tun_net_close,
 819        .ndo_start_xmit         = tun_net_xmit,
 820        .ndo_change_mtu         = tun_net_change_mtu,
 821        .ndo_fix_features       = tun_net_fix_features,
 822        .ndo_select_queue       = tun_select_queue,
 823#ifdef CONFIG_NET_POLL_CONTROLLER
 824        .ndo_poll_controller    = tun_poll_controller,
 825#endif
 826};
 827
 828static const struct net_device_ops tap_netdev_ops = {
 829        .ndo_uninit             = tun_net_uninit,
 830        .ndo_open               = tun_net_open,
 831        .ndo_stop               = tun_net_close,
 832        .ndo_start_xmit         = tun_net_xmit,
 833        .ndo_change_mtu         = tun_net_change_mtu,
 834        .ndo_fix_features       = tun_net_fix_features,
 835        .ndo_set_rx_mode        = tun_net_mclist,
 836        .ndo_set_mac_address    = eth_mac_addr,
 837        .ndo_validate_addr      = eth_validate_addr,
 838        .ndo_select_queue       = tun_select_queue,
 839#ifdef CONFIG_NET_POLL_CONTROLLER
 840        .ndo_poll_controller    = tun_poll_controller,
 841#endif
 842};
 843
 844static int tun_flow_init(struct tun_struct *tun)
 845{
 846        int i;
 847
 848        for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
 849                INIT_HLIST_HEAD(&tun->flows[i]);
 850
 851        tun->ageing_time = TUN_FLOW_EXPIRE;
 852        setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
 853        mod_timer(&tun->flow_gc_timer,
 854                  round_jiffies_up(jiffies + tun->ageing_time));
 855
 856        return 0;
 857}
 858
 859static void tun_flow_uninit(struct tun_struct *tun)
 860{
 861        del_timer_sync(&tun->flow_gc_timer);
 862        tun_flow_flush(tun);
 863}
 864
 865/* Initialize net device. */
 866static void tun_net_init(struct net_device *dev)
 867{
 868        struct tun_struct *tun = netdev_priv(dev);
 869
 870        switch (tun->flags & TUN_TYPE_MASK) {
 871        case TUN_TUN_DEV:
 872                dev->netdev_ops = &tun_netdev_ops;
 873
 874                /* Point-to-Point TUN Device */
 875                dev->hard_header_len = 0;
 876                dev->addr_len = 0;
 877                dev->mtu = 1500;
 878
 879                /* Zero header length */
 880                dev->type = ARPHRD_NONE;
 881                dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 882                dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 883                break;
 884
 885        case TUN_TAP_DEV:
 886                dev->netdev_ops = &tap_netdev_ops;
 887                /* Ethernet TAP Device */
 888                ether_setup(dev);
 889                dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 890                dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
 891
 892                eth_hw_addr_random(dev);
 893
 894                dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 895                break;
 896        }
 897}
 898
 899/* Character device part */
 900
 901/* Poll */
 902static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
 903{
 904        struct tun_file *tfile = file->private_data;
 905        struct tun_struct *tun = __tun_get(tfile);
 906        struct sock *sk;
 907        unsigned int mask = 0;
 908
 909        if (!tun)
 910                return POLLERR;
 911
 912        sk = tfile->socket.sk;
 913
 914        tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
 915
 916        poll_wait(file, &tfile->wq.wait, wait);
 917
 918        if (!skb_queue_empty(&sk->sk_receive_queue))
 919                mask |= POLLIN | POLLRDNORM;
 920
 921        if (sock_writeable(sk) ||
 922            (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 923             sock_writeable(sk)))
 924                mask |= POLLOUT | POLLWRNORM;
 925
 926        if (tun->dev->reg_state != NETREG_REGISTERED)
 927                mask = POLLERR;
 928
 929        tun_put(tun);
 930        return mask;
 931}
 932
 933/* prepad is the amount to reserve at front.  len is length after that.
 934 * linear is a hint as to how much to copy (usually headers). */
 935static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
 936                                     size_t prepad, size_t len,
 937                                     size_t linear, int noblock)
 938{
 939        struct sock *sk = tfile->socket.sk;
 940        struct sk_buff *skb;
 941        int err;
 942
 943        /* Under a page?  Don't bother with paged skb. */
 944        if (prepad + len < PAGE_SIZE || !linear)
 945                linear = len;
 946
 947        skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 948                                   &err);
 949        if (!skb)
 950                return ERR_PTR(err);
 951
 952        skb_reserve(skb, prepad);
 953        skb_put(skb, linear);
 954        skb->data_len = len - linear;
 955        skb->len += len - linear;
 956
 957        return skb;
 958}
 959
 960/* set skb frags from iovec, this can move to core network code for reuse */
 961static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
 962                                  int offset, size_t count)
 963{
 964        int len = iov_length(from, count) - offset;
 965        int copy = skb_headlen(skb);
 966        int size, offset1 = 0;
 967        int i = 0;
 968
 969        /* Skip over from offset */
 970        while (count && (offset >= from->iov_len)) {
 971                offset -= from->iov_len;
 972                ++from;
 973                --count;
 974        }
 975
 976        /* copy up to skb headlen */
 977        while (count && (copy > 0)) {
 978                size = min_t(unsigned int, copy, from->iov_len - offset);
 979                if (copy_from_user(skb->data + offset1, from->iov_base + offset,
 980                                   size))
 981                        return -EFAULT;
 982                if (copy > size) {
 983                        ++from;
 984                        --count;
 985                        offset = 0;
 986                } else
 987                        offset += size;
 988                copy -= size;
 989                offset1 += size;
 990        }
 991
 992        if (len == offset1)
 993                return 0;
 994
 995        while (count--) {
 996                struct page *page[MAX_SKB_FRAGS];
 997                int num_pages;
 998                unsigned long base;
 999                unsigned long truesize;
1000
1001                len = from->iov_len - offset;
1002                if (!len) {
1003                        offset = 0;
1004                        ++from;
1005                        continue;
1006                }
1007                base = (unsigned long)from->iov_base + offset;
1008                size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
1009                if (i + size > MAX_SKB_FRAGS)
1010                        return -EMSGSIZE;
1011                num_pages = get_user_pages_fast(base, size, 0, &page[i]);
1012                if (num_pages != size) {
1013                        int j;
1014
1015                        for (j = 0; j < num_pages; j++)
1016                                put_page(page[i + j]);
1017                        return -EFAULT;
1018                }
1019                truesize = size * PAGE_SIZE;
1020                skb->data_len += len;
1021                skb->len += len;
1022                skb->truesize += truesize;
1023                atomic_add(truesize, &skb->sk->sk_wmem_alloc);
1024                while (len) {
1025                        int off = base & ~PAGE_MASK;
1026                        int size = min_t(int, len, PAGE_SIZE - off);
1027                        __skb_fill_page_desc(skb, i, page[i], off, size);
1028                        skb_shinfo(skb)->nr_frags++;
1029                        /* increase sk_wmem_alloc */
1030                        base += size;
1031                        len -= size;
1032                        i++;
1033                }
1034                offset = 0;
1035                ++from;
1036        }
1037        return 0;
1038}
1039
1040/* Get packet from user space buffer */
1041static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1042                            void *msg_control, const struct iovec *iv,
1043                            size_t total_len, size_t count, int noblock)
1044{
1045        struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1046        struct sk_buff *skb;
1047        size_t len = total_len, align = NET_SKB_PAD;
1048        struct virtio_net_hdr gso = { 0 };
1049        int offset = 0;
1050        int copylen;
1051        bool zerocopy = false;
1052        int err;
1053        u32 rxhash;
1054
1055        if (!(tun->flags & TUN_NO_PI)) {
1056                if ((len -= sizeof(pi)) > total_len)
1057                        return -EINVAL;
1058
1059                if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
1060                        return -EFAULT;
1061                offset += sizeof(pi);
1062        }
1063
1064        if (tun->flags & TUN_VNET_HDR) {
1065                if ((len -= tun->vnet_hdr_sz) > total_len)
1066                        return -EINVAL;
1067
1068                if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
1069                        return -EFAULT;
1070
1071                if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1072                    gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
1073                        gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
1074
1075                if (gso.hdr_len > len)
1076                        return -EINVAL;
1077                offset += tun->vnet_hdr_sz;
1078        }
1079
1080        if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
1081                align += NET_IP_ALIGN;
1082                if (unlikely(len < ETH_HLEN ||
1083                             (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
1084                        return -EINVAL;
1085        }
1086
1087        if (msg_control)
1088                zerocopy = true;
1089
1090        if (zerocopy) {
1091                /* Userspace may produce vectors with count greater than
1092                 * MAX_SKB_FRAGS, so we need to linearize parts of the skb
1093                 * to let the rest of data to be fit in the frags.
1094                 */
1095                if (count > MAX_SKB_FRAGS) {
1096                        copylen = iov_length(iv, count - MAX_SKB_FRAGS);
1097                        if (copylen < offset)
1098                                copylen = 0;
1099                        else
1100                                copylen -= offset;
1101                } else
1102                                copylen = 0;
1103                /* There are 256 bytes to be copied in skb, so there is enough
1104                 * room for skb expand head in case it is used.
1105                 * The rest of the buffer is mapped from userspace.
1106                 */
1107                if (copylen < gso.hdr_len)
1108                        copylen = gso.hdr_len;
1109                if (!copylen)
1110                        copylen = GOODCOPY_LEN;
1111        } else
1112                copylen = len;
1113
1114        skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, noblock);
1115        if (IS_ERR(skb)) {
1116                if (PTR_ERR(skb) != -EAGAIN)
1117                        tun->dev->stats.rx_dropped++;
1118                return PTR_ERR(skb);
1119        }
1120
1121        if (zerocopy)
1122                err = zerocopy_sg_from_iovec(skb, iv, offset, count);
1123        else
1124                err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
1125
1126        if (err) {
1127                tun->dev->stats.rx_dropped++;
1128                kfree_skb(skb);
1129                return -EFAULT;
1130        }
1131
1132        if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1133                if (!skb_partial_csum_set(skb, gso.csum_start,
1134                                          gso.csum_offset)) {
1135                        tun->dev->stats.rx_frame_errors++;
1136                        kfree_skb(skb);
1137                        return -EINVAL;
1138                }
1139        }
1140
1141        switch (tun->flags & TUN_TYPE_MASK) {
1142        case TUN_TUN_DEV:
1143                if (tun->flags & TUN_NO_PI) {
1144                        switch (skb->data[0] & 0xf0) {
1145                        case 0x40:
1146                                pi.proto = htons(ETH_P_IP);
1147                                break;
1148                        case 0x60:
1149                                pi.proto = htons(ETH_P_IPV6);
1150                                break;
1151                        default:
1152                                tun->dev->stats.rx_dropped++;
1153                                kfree_skb(skb);
1154                                return -EINVAL;
1155                        }
1156                }
1157
1158                skb_reset_mac_header(skb);
1159                skb->protocol = pi.proto;
1160                skb->dev = tun->dev;
1161                break;
1162        case TUN_TAP_DEV:
1163                skb->protocol = eth_type_trans(skb, tun->dev);
1164                break;
1165        }
1166
1167        if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1168                pr_debug("GSO!\n");
1169                switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1170                case VIRTIO_NET_HDR_GSO_TCPV4:
1171                        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1172                        break;
1173                case VIRTIO_NET_HDR_GSO_TCPV6:
1174                        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1175                        break;
1176                case VIRTIO_NET_HDR_GSO_UDP:
1177                        skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1178                        break;
1179                default:
1180                        tun->dev->stats.rx_frame_errors++;
1181                        kfree_skb(skb);
1182                        return -EINVAL;
1183                }
1184
1185                if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1186                        skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1187
1188                skb_shinfo(skb)->gso_size = gso.gso_size;
1189                if (skb_shinfo(skb)->gso_size == 0) {
1190                        tun->dev->stats.rx_frame_errors++;
1191                        kfree_skb(skb);
1192                        return -EINVAL;
1193                }
1194
1195                /* Header must be checked, and gso_segs computed. */
1196                skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1197                skb_shinfo(skb)->gso_segs = 0;
1198        }
1199
1200        /* copy skb_ubuf_info for callback when skb has no error */
1201        if (zerocopy) {
1202                skb_shinfo(skb)->destructor_arg = msg_control;
1203                skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1204                skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1205        }
1206
1207        skb_reset_network_header(skb);
1208        skb_probe_transport_header(skb, 0);
1209
1210        rxhash = skb_get_rxhash(skb);
1211        netif_rx_ni(skb);
1212
1213        tun->dev->stats.rx_packets++;
1214        tun->dev->stats.rx_bytes += len;
1215
1216        tun_flow_update(tun, rxhash, tfile);
1217        return total_len;
1218}
1219
1220static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
1221                              unsigned long count, loff_t pos)
1222{
1223        struct file *file = iocb->ki_filp;
1224        struct tun_struct *tun = tun_get(file);
1225        struct tun_file *tfile = file->private_data;
1226        ssize_t result;
1227
1228        if (!tun)
1229                return -EBADFD;
1230
1231        tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
1232
1233        result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count),
1234                              count, file->f_flags & O_NONBLOCK);
1235
1236        tun_put(tun);
1237        return result;
1238}
1239
1240/* Put packet to the user space buffer */
1241static ssize_t tun_put_user(struct tun_struct *tun,
1242                            struct tun_file *tfile,
1243                            struct sk_buff *skb,
1244                            const struct iovec *iv, int len)
1245{
1246        struct tun_pi pi = { 0, skb->protocol };
1247        ssize_t total = 0;
1248
1249        if (!(tun->flags & TUN_NO_PI)) {
1250                if ((len -= sizeof(pi)) < 0)
1251                        return -EINVAL;
1252
1253                if (len < skb->len) {
1254                        /* Packet will be striped */
1255                        pi.flags |= TUN_PKT_STRIP;
1256                }
1257
1258                if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
1259                        return -EFAULT;
1260                total += sizeof(pi);
1261        }
1262
1263        if (tun->flags & TUN_VNET_HDR) {
1264                struct virtio_net_hdr gso = { 0 }; /* no info leak */
1265                if ((len -= tun->vnet_hdr_sz) < 0)
1266                        return -EINVAL;
1267
1268                if (skb_is_gso(skb)) {
1269                        struct skb_shared_info *sinfo = skb_shinfo(skb);
1270
1271                        /* This is a hint as to how much should be linear. */
1272                        gso.hdr_len = skb_headlen(skb);
1273                        gso.gso_size = sinfo->gso_size;
1274                        if (sinfo->gso_type & SKB_GSO_TCPV4)
1275                                gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1276                        else if (sinfo->gso_type & SKB_GSO_TCPV6)
1277                                gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1278                        else if (sinfo->gso_type & SKB_GSO_UDP)
1279                                gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1280                        else {
1281                                pr_err("unexpected GSO type: "
1282                                       "0x%x, gso_size %d, hdr_len %d\n",
1283                                       sinfo->gso_type, gso.gso_size,
1284                                       gso.hdr_len);
1285                                print_hex_dump(KERN_ERR, "tun: ",
1286                                               DUMP_PREFIX_NONE,
1287                                               16, 1, skb->head,
1288                                               min((int)gso.hdr_len, 64), true);
1289                                WARN_ON_ONCE(1);
1290                                return -EINVAL;
1291                        }
1292                        if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1293                                gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1294                } else
1295                        gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1296
1297                if (skb->ip_summed == CHECKSUM_PARTIAL) {
1298                        gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1299                        gso.csum_start = skb_checksum_start_offset(skb);
1300                        gso.csum_offset = skb->csum_offset;
1301                } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1302                        gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1303                } /* else everything is zero */
1304
1305                if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
1306                                               sizeof(gso))))
1307                        return -EFAULT;
1308                total += tun->vnet_hdr_sz;
1309        }
1310
1311        len = min_t(int, skb->len, len);
1312
1313        skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
1314        total += skb->len;
1315
1316        tun->dev->stats.tx_packets++;
1317        tun->dev->stats.tx_bytes += len;
1318
1319        return total;
1320}
1321
1322static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1323                           struct kiocb *iocb, const struct iovec *iv,
1324                           ssize_t len, int noblock)
1325{
1326        DECLARE_WAITQUEUE(wait, current);
1327        struct sk_buff *skb;
1328        ssize_t ret = 0;
1329
1330        tun_debug(KERN_INFO, tun, "tun_do_read\n");
1331
1332        if (unlikely(!noblock))
1333                add_wait_queue(&tfile->wq.wait, &wait);
1334        while (len) {
1335                current->state = TASK_INTERRUPTIBLE;
1336
1337                /* Read frames from the queue */
1338                if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) {
1339                        if (noblock) {
1340                                ret = -EAGAIN;
1341                                break;
1342                        }
1343                        if (signal_pending(current)) {
1344                                ret = -ERESTARTSYS;
1345                                break;
1346                        }
1347                        if (tun->dev->reg_state != NETREG_REGISTERED) {
1348                                ret = -EIO;
1349                                break;
1350                        }
1351
1352                        /* Nothing to read, let's sleep */
1353                        schedule();
1354                        continue;
1355                }
1356
1357                ret = tun_put_user(tun, tfile, skb, iv, len);
1358                kfree_skb(skb);
1359                break;
1360        }
1361
1362        current->state = TASK_RUNNING;
1363        if (unlikely(!noblock))
1364                remove_wait_queue(&tfile->wq.wait, &wait);
1365
1366        return ret;
1367}
1368
1369static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1370                            unsigned long count, loff_t pos)
1371{
1372        struct file *file = iocb->ki_filp;
1373        struct tun_file *tfile = file->private_data;
1374        struct tun_struct *tun = __tun_get(tfile);
1375        ssize_t len, ret;
1376
1377        if (!tun)
1378                return -EBADFD;
1379        len = iov_length(iv, count);
1380        if (len < 0) {
1381                ret = -EINVAL;
1382                goto out;
1383        }
1384
1385        ret = tun_do_read(tun, tfile, iocb, iv, len,
1386                          file->f_flags & O_NONBLOCK);
1387        ret = min_t(ssize_t, ret, len);
1388out:
1389        tun_put(tun);
1390        return ret;
1391}
1392
1393static void tun_free_netdev(struct net_device *dev)
1394{
1395        struct tun_struct *tun = netdev_priv(dev);
1396
1397        BUG_ON(!(list_empty(&tun->disabled)));
1398        tun_flow_uninit(tun);
1399        security_tun_dev_free_security(tun->security);
1400        free_netdev(dev);
1401}
1402
1403static void tun_setup(struct net_device *dev)
1404{
1405        struct tun_struct *tun = netdev_priv(dev);
1406
1407        tun->owner = INVALID_UID;
1408        tun->group = INVALID_GID;
1409
1410        dev->ethtool_ops = &tun_ethtool_ops;
1411        dev->destructor = tun_free_netdev;
1412}
1413
1414/* Trivial set of netlink ops to allow deleting tun or tap
1415 * device with netlink.
1416 */
1417static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1418{
1419        return -EINVAL;
1420}
1421
1422static struct rtnl_link_ops tun_link_ops __read_mostly = {
1423        .kind           = DRV_NAME,
1424        .priv_size      = sizeof(struct tun_struct),
1425        .setup          = tun_setup,
1426        .validate       = tun_validate,
1427};
1428
1429static void tun_sock_write_space(struct sock *sk)
1430{
1431        struct tun_file *tfile;
1432        wait_queue_head_t *wqueue;
1433
1434        if (!sock_writeable(sk))
1435                return;
1436
1437        if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1438                return;
1439
1440        wqueue = sk_sleep(sk);
1441        if (wqueue && waitqueue_active(wqueue))
1442                wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1443                                                POLLWRNORM | POLLWRBAND);
1444
1445        tfile = container_of(sk, struct tun_file, sk);
1446        kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1447}
1448
1449static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1450                       struct msghdr *m, size_t total_len)
1451{
1452        int ret;
1453        struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1454        struct tun_struct *tun = __tun_get(tfile);
1455
1456        if (!tun)
1457                return -EBADFD;
1458        ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len,
1459                           m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1460        tun_put(tun);
1461        return ret;
1462}
1463
1464
1465static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1466                       struct msghdr *m, size_t total_len,
1467                       int flags)
1468{
1469        struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1470        struct tun_struct *tun = __tun_get(tfile);
1471        int ret;
1472
1473        if (!tun)
1474                return -EBADFD;
1475
1476        if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) {
1477                ret = -EINVAL;
1478                goto out;
1479        }
1480        ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len,
1481                          flags & MSG_DONTWAIT);
1482        if (ret > total_len) {
1483                m->msg_flags |= MSG_TRUNC;
1484                ret = flags & MSG_TRUNC ? ret : total_len;
1485        }
1486out:
1487        tun_put(tun);
1488        return ret;
1489}
1490
1491static int tun_release(struct socket *sock)
1492{
1493        if (sock->sk)
1494                sock_put(sock->sk);
1495        return 0;
1496}
1497
1498/* Ops structure to mimic raw sockets with tun */
1499static const struct proto_ops tun_socket_ops = {
1500        .sendmsg = tun_sendmsg,
1501        .recvmsg = tun_recvmsg,
1502        .release = tun_release,
1503};
1504
1505static struct proto tun_proto = {
1506        .name           = "tun",
1507        .owner          = THIS_MODULE,
1508        .obj_size       = sizeof(struct tun_file),
1509};
1510
1511static int tun_flags(struct tun_struct *tun)
1512{
1513        int flags = 0;
1514
1515        if (tun->flags & TUN_TUN_DEV)
1516                flags |= IFF_TUN;
1517        else
1518                flags |= IFF_TAP;
1519
1520        if (tun->flags & TUN_NO_PI)
1521                flags |= IFF_NO_PI;
1522
1523        /* This flag has no real effect.  We track the value for backwards
1524         * compatibility.
1525         */
1526        if (tun->flags & TUN_ONE_QUEUE)
1527                flags |= IFF_ONE_QUEUE;
1528
1529        if (tun->flags & TUN_VNET_HDR)
1530                flags |= IFF_VNET_HDR;
1531
1532        if (tun->flags & TUN_TAP_MQ)
1533                flags |= IFF_MULTI_QUEUE;
1534
1535        return flags;
1536}
1537
1538static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1539                              char *buf)
1540{
1541        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1542        return sprintf(buf, "0x%x\n", tun_flags(tun));
1543}
1544
1545static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1546                              char *buf)
1547{
1548        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1549        return uid_valid(tun->owner)?
1550                sprintf(buf, "%u\n",
1551                        from_kuid_munged(current_user_ns(), tun->owner)):
1552                sprintf(buf, "-1\n");
1553}
1554
1555static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1556                              char *buf)
1557{
1558        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1559        return gid_valid(tun->group) ?
1560                sprintf(buf, "%u\n",
1561                        from_kgid_munged(current_user_ns(), tun->group)):
1562                sprintf(buf, "-1\n");
1563}
1564
1565static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1566static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1567static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1568
1569static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1570{
1571        struct tun_struct *tun;
1572        struct tun_file *tfile = file->private_data;
1573        struct net_device *dev;
1574        int err;
1575
1576        if (tfile->detached)
1577                return -EINVAL;
1578
1579        dev = __dev_get_by_name(net, ifr->ifr_name);
1580        if (dev) {
1581                if (ifr->ifr_flags & IFF_TUN_EXCL)
1582                        return -EBUSY;
1583                if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1584                        tun = netdev_priv(dev);
1585                else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1586                        tun = netdev_priv(dev);
1587                else
1588                        return -EINVAL;
1589
1590                if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1591                    !!(tun->flags & TUN_TAP_MQ))
1592                        return -EINVAL;
1593
1594                if (tun_not_capable(tun))
1595                        return -EPERM;
1596                err = security_tun_dev_open(tun->security);
1597                if (err < 0)
1598                        return err;
1599
1600                err = tun_attach(tun, file);
1601                if (err < 0)
1602                        return err;
1603
1604                if (tun->flags & TUN_TAP_MQ &&
1605                    (tun->numqueues + tun->numdisabled > 1)) {
1606                        /* One or more queue has already been attached, no need
1607                         * to initialize the device again.
1608                         */
1609                        return 0;
1610                }
1611        }
1612        else {
1613                char *name;
1614                unsigned long flags = 0;
1615                int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1616                             MAX_TAP_QUEUES : 1;
1617
1618                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1619                        return -EPERM;
1620                err = security_tun_dev_create();
1621                if (err < 0)
1622                        return err;
1623
1624                /* Set dev type */
1625                if (ifr->ifr_flags & IFF_TUN) {
1626                        /* TUN device */
1627                        flags |= TUN_TUN_DEV;
1628                        name = "tun%d";
1629                } else if (ifr->ifr_flags & IFF_TAP) {
1630                        /* TAP device */
1631                        flags |= TUN_TAP_DEV;
1632                        name = "tap%d";
1633                } else
1634                        return -EINVAL;
1635
1636                if (*ifr->ifr_name)
1637                        name = ifr->ifr_name;
1638
1639                dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1640                                       tun_setup, queues, queues);
1641
1642                if (!dev)
1643                        return -ENOMEM;
1644
1645                dev_net_set(dev, net);
1646                dev->rtnl_link_ops = &tun_link_ops;
1647
1648                tun = netdev_priv(dev);
1649                tun->dev = dev;
1650                tun->flags = flags;
1651                tun->txflt.count = 0;
1652                tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1653
1654                tun->filter_attached = false;
1655                tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1656
1657                spin_lock_init(&tun->lock);
1658
1659                err = security_tun_dev_alloc_security(&tun->security);
1660                if (err < 0)
1661                        goto err_free_dev;
1662
1663                tun_net_init(dev);
1664
1665                err = tun_flow_init(tun);
1666                if (err < 0)
1667                        goto err_free_dev;
1668
1669                dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1670                        TUN_USER_FEATURES;
1671                dev->features = dev->hw_features;
1672                dev->vlan_features = dev->features;
1673
1674                INIT_LIST_HEAD(&tun->disabled);
1675                err = tun_attach(tun, file);
1676                if (err < 0)
1677                        goto err_free_dev;
1678
1679                err = register_netdevice(tun->dev);
1680                if (err < 0)
1681                        goto err_free_dev;
1682
1683                if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1684                    device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1685                    device_create_file(&tun->dev->dev, &dev_attr_group))
1686                        pr_err("Failed to create tun sysfs files\n");
1687        }
1688
1689        netif_carrier_on(tun->dev);
1690
1691        tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1692
1693        if (ifr->ifr_flags & IFF_NO_PI)
1694                tun->flags |= TUN_NO_PI;
1695        else
1696                tun->flags &= ~TUN_NO_PI;
1697
1698        /* This flag has no real effect.  We track the value for backwards
1699         * compatibility.
1700         */
1701        if (ifr->ifr_flags & IFF_ONE_QUEUE)
1702                tun->flags |= TUN_ONE_QUEUE;
1703        else
1704                tun->flags &= ~TUN_ONE_QUEUE;
1705
1706        if (ifr->ifr_flags & IFF_VNET_HDR)
1707                tun->flags |= TUN_VNET_HDR;
1708        else
1709                tun->flags &= ~TUN_VNET_HDR;
1710
1711        if (ifr->ifr_flags & IFF_MULTI_QUEUE)
1712                tun->flags |= TUN_TAP_MQ;
1713        else
1714                tun->flags &= ~TUN_TAP_MQ;
1715
1716        /* Make sure persistent devices do not get stuck in
1717         * xoff state.
1718         */
1719        if (netif_running(tun->dev))
1720                netif_tx_wake_all_queues(tun->dev);
1721
1722        strcpy(ifr->ifr_name, tun->dev->name);
1723        return 0;
1724
1725 err_free_dev:
1726        free_netdev(dev);
1727        return err;
1728}
1729
1730static void tun_get_iff(struct net *net, struct tun_struct *tun,
1731                       struct ifreq *ifr)
1732{
1733        tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1734
1735        strcpy(ifr->ifr_name, tun->dev->name);
1736
1737        ifr->ifr_flags = tun_flags(tun);
1738
1739}
1740
1741/* This is like a cut-down ethtool ops, except done via tun fd so no
1742 * privs required. */
1743static int set_offload(struct tun_struct *tun, unsigned long arg)
1744{
1745        netdev_features_t features = 0;
1746
1747        if (arg & TUN_F_CSUM) {
1748                features |= NETIF_F_HW_CSUM;
1749                arg &= ~TUN_F_CSUM;
1750
1751                if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1752                        if (arg & TUN_F_TSO_ECN) {
1753                                features |= NETIF_F_TSO_ECN;
1754                                arg &= ~TUN_F_TSO_ECN;
1755                        }
1756                        if (arg & TUN_F_TSO4)
1757                                features |= NETIF_F_TSO;
1758                        if (arg & TUN_F_TSO6)
1759                                features |= NETIF_F_TSO6;
1760                        arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1761                }
1762
1763                if (arg & TUN_F_UFO) {
1764                        features |= NETIF_F_UFO;
1765                        arg &= ~TUN_F_UFO;
1766                }
1767        }
1768
1769        /* This gives the user a way to test for new features in future by
1770         * trying to set them. */
1771        if (arg)
1772                return -EINVAL;
1773
1774        tun->set_features = features;
1775        netdev_update_features(tun->dev);
1776
1777        return 0;
1778}
1779
1780static void tun_detach_filter(struct tun_struct *tun, int n)
1781{
1782        int i;
1783        struct tun_file *tfile;
1784
1785        for (i = 0; i < n; i++) {
1786                tfile = rtnl_dereference(tun->tfiles[i]);
1787                sk_detach_filter(tfile->socket.sk);
1788        }
1789
1790        tun->filter_attached = false;
1791}
1792
1793static int tun_attach_filter(struct tun_struct *tun)
1794{
1795        int i, ret = 0;
1796        struct tun_file *tfile;
1797
1798        for (i = 0; i < tun->numqueues; i++) {
1799                tfile = rtnl_dereference(tun->tfiles[i]);
1800                ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1801                if (ret) {
1802                        tun_detach_filter(tun, i);
1803                        return ret;
1804                }
1805        }
1806
1807        tun->filter_attached = true;
1808        return ret;
1809}
1810
1811static void tun_set_sndbuf(struct tun_struct *tun)
1812{
1813        struct tun_file *tfile;
1814        int i;
1815
1816        for (i = 0; i < tun->numqueues; i++) {
1817                tfile = rtnl_dereference(tun->tfiles[i]);
1818                tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1819        }
1820}
1821
1822static int tun_set_queue(struct file *file, struct ifreq *ifr)
1823{
1824        struct tun_file *tfile = file->private_data;
1825        struct tun_struct *tun;
1826        int ret = 0;
1827
1828        rtnl_lock();
1829
1830        if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1831                tun = tfile->detached;
1832                if (!tun) {
1833                        ret = -EINVAL;
1834                        goto unlock;
1835                }
1836                ret = security_tun_dev_attach_queue(tun->security);
1837                if (ret < 0)
1838                        goto unlock;
1839                ret = tun_attach(tun, file);
1840        } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1841                tun = rtnl_dereference(tfile->tun);
1842                if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached)
1843                        ret = -EINVAL;
1844                else
1845                        __tun_detach(tfile, false);
1846        } else
1847                ret = -EINVAL;
1848
1849unlock:
1850        rtnl_unlock();
1851        return ret;
1852}
1853
1854static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1855                            unsigned long arg, int ifreq_len)
1856{
1857        struct tun_file *tfile = file->private_data;
1858        struct tun_struct *tun;
1859        void __user* argp = (void __user*)arg;
1860        struct ifreq ifr;
1861        kuid_t owner;
1862        kgid_t group;
1863        int sndbuf;
1864        int vnet_hdr_sz;
1865        int ret;
1866
1867        if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1868                if (copy_from_user(&ifr, argp, ifreq_len))
1869                        return -EFAULT;
1870        } else {
1871                memset(&ifr, 0, sizeof(ifr));
1872        }
1873        if (cmd == TUNGETFEATURES) {
1874                /* Currently this just means: "what IFF flags are valid?".
1875                 * This is needed because we never checked for invalid flags on
1876                 * TUNSETIFF. */
1877                return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1878                                IFF_VNET_HDR | IFF_MULTI_QUEUE,
1879                                (unsigned int __user*)argp);
1880        } else if (cmd == TUNSETQUEUE)
1881                return tun_set_queue(file, &ifr);
1882
1883        ret = 0;
1884        rtnl_lock();
1885
1886        tun = __tun_get(tfile);
1887        if (cmd == TUNSETIFF && !tun) {
1888                ifr.ifr_name[IFNAMSIZ-1] = '\0';
1889
1890                ret = tun_set_iff(tfile->net, file, &ifr);
1891
1892                if (ret)
1893                        goto unlock;
1894
1895                if (copy_to_user(argp, &ifr, ifreq_len))
1896                        ret = -EFAULT;
1897                goto unlock;
1898        }
1899
1900        ret = -EBADFD;
1901        if (!tun)
1902                goto unlock;
1903
1904        tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1905
1906        ret = 0;
1907        switch (cmd) {
1908        case TUNGETIFF:
1909                tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1910
1911                if (copy_to_user(argp, &ifr, ifreq_len))
1912                        ret = -EFAULT;
1913                break;
1914
1915        case TUNSETNOCSUM:
1916                /* Disable/Enable checksum */
1917
1918                /* [unimplemented] */
1919                tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1920                          arg ? "disabled" : "enabled");
1921                break;
1922
1923        case TUNSETPERSIST:
1924                /* Disable/Enable persist mode. Keep an extra reference to the
1925                 * module to prevent the module being unprobed.
1926                 */
1927                if (arg && !(tun->flags & TUN_PERSIST)) {
1928                        tun->flags |= TUN_PERSIST;
1929                        __module_get(THIS_MODULE);
1930                }
1931                if (!arg && (tun->flags & TUN_PERSIST)) {
1932                        tun->flags &= ~TUN_PERSIST;
1933                        module_put(THIS_MODULE);
1934                }
1935
1936                tun_debug(KERN_INFO, tun, "persist %s\n",
1937                          arg ? "enabled" : "disabled");
1938                break;
1939
1940        case TUNSETOWNER:
1941                /* Set owner of the device */
1942                owner = make_kuid(current_user_ns(), arg);
1943                if (!uid_valid(owner)) {
1944                        ret = -EINVAL;
1945                        break;
1946                }
1947                tun->owner = owner;
1948                tun_debug(KERN_INFO, tun, "owner set to %u\n",
1949                          from_kuid(&init_user_ns, tun->owner));
1950                break;
1951
1952        case TUNSETGROUP:
1953                /* Set group of the device */
1954                group = make_kgid(current_user_ns(), arg);
1955                if (!gid_valid(group)) {
1956                        ret = -EINVAL;
1957                        break;
1958                }
1959                tun->group = group;
1960                tun_debug(KERN_INFO, tun, "group set to %u\n",
1961                          from_kgid(&init_user_ns, tun->group));
1962                break;
1963
1964        case TUNSETLINK:
1965                /* Only allow setting the type when the interface is down */
1966                if (tun->dev->flags & IFF_UP) {
1967                        tun_debug(KERN_INFO, tun,
1968                                  "Linktype set failed because interface is up\n");
1969                        ret = -EBUSY;
1970                } else {
1971                        tun->dev->type = (int) arg;
1972                        tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1973                                  tun->dev->type);
1974                        ret = 0;
1975                }
1976                break;
1977
1978#ifdef TUN_DEBUG
1979        case TUNSETDEBUG:
1980                tun->debug = arg;
1981                break;
1982#endif
1983        case TUNSETOFFLOAD:
1984                ret = set_offload(tun, arg);
1985                break;
1986
1987        case TUNSETTXFILTER:
1988                /* Can be set only for TAPs */
1989                ret = -EINVAL;
1990                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1991                        break;
1992                ret = update_filter(&tun->txflt, (void __user *)arg);
1993                break;
1994
1995        case SIOCGIFHWADDR:
1996                /* Get hw address */
1997                memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1998                ifr.ifr_hwaddr.sa_family = tun->dev->type;
1999                if (copy_to_user(argp, &ifr, ifreq_len))
2000                        ret = -EFAULT;
2001                break;
2002
2003        case SIOCSIFHWADDR:
2004                /* Set hw address */
2005                tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2006                          ifr.ifr_hwaddr.sa_data);
2007
2008                ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2009                break;
2010
2011        case TUNGETSNDBUF:
2012                sndbuf = tfile->socket.sk->sk_sndbuf;
2013                if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2014                        ret = -EFAULT;
2015                break;
2016
2017        case TUNSETSNDBUF:
2018                if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2019                        ret = -EFAULT;
2020                        break;
2021                }
2022
2023                tun->sndbuf = sndbuf;
2024                tun_set_sndbuf(tun);
2025                break;
2026
2027        case TUNGETVNETHDRSZ:
2028                vnet_hdr_sz = tun->vnet_hdr_sz;
2029                if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2030                        ret = -EFAULT;
2031                break;
2032
2033        case TUNSETVNETHDRSZ:
2034                if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2035                        ret = -EFAULT;
2036                        break;
2037                }
2038                if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2039                        ret = -EINVAL;
2040                        break;
2041                }
2042
2043                tun->vnet_hdr_sz = vnet_hdr_sz;
2044                break;
2045
2046        case TUNATTACHFILTER:
2047                /* Can be set only for TAPs */
2048                ret = -EINVAL;
2049                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2050                        break;
2051                ret = -EFAULT;
2052                if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2053                        break;
2054
2055                ret = tun_attach_filter(tun);
2056                break;
2057
2058        case TUNDETACHFILTER:
2059                /* Can be set only for TAPs */
2060                ret = -EINVAL;
2061                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2062                        break;
2063                ret = 0;
2064                tun_detach_filter(tun, tun->numqueues);
2065                break;
2066
2067        default:
2068                ret = -EINVAL;
2069                break;
2070        }
2071
2072unlock:
2073        rtnl_unlock();
2074        if (tun)
2075                tun_put(tun);
2076        return ret;
2077}
2078
2079static long tun_chr_ioctl(struct file *file,
2080                          unsigned int cmd, unsigned long arg)
2081{
2082        return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2083}
2084
2085#ifdef CONFIG_COMPAT
2086static long tun_chr_compat_ioctl(struct file *file,
2087                         unsigned int cmd, unsigned long arg)
2088{
2089        switch (cmd) {
2090        case TUNSETIFF:
2091        case TUNGETIFF:
2092        case TUNSETTXFILTER:
2093        case TUNGETSNDBUF:
2094        case TUNSETSNDBUF:
2095        case SIOCGIFHWADDR:
2096        case SIOCSIFHWADDR:
2097                arg = (unsigned long)compat_ptr(arg);
2098                break;
2099        default:
2100                arg = (compat_ulong_t)arg;
2101                break;
2102        }
2103
2104        /*
2105         * compat_ifreq is shorter than ifreq, so we must not access beyond
2106         * the end of that structure. All fields that are used in this
2107         * driver are compatible though, we don't need to convert the
2108         * contents.
2109         */
2110        return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2111}
2112#endif /* CONFIG_COMPAT */
2113
2114static int tun_chr_fasync(int fd, struct file *file, int on)
2115{
2116        struct tun_file *tfile = file->private_data;
2117        int ret;
2118
2119        if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2120                goto out;
2121
2122        if (on) {
2123                ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2124                if (ret)
2125                        goto out;
2126                tfile->flags |= TUN_FASYNC;
2127        } else
2128                tfile->flags &= ~TUN_FASYNC;
2129        ret = 0;
2130out:
2131        return ret;
2132}
2133
2134static int tun_chr_open(struct inode *inode, struct file * file)
2135{
2136        struct tun_file *tfile;
2137
2138        DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2139
2140        tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
2141                                            &tun_proto);
2142        if (!tfile)
2143                return -ENOMEM;
2144        rcu_assign_pointer(tfile->tun, NULL);
2145        tfile->net = get_net(current->nsproxy->net_ns);
2146        tfile->flags = 0;
2147
2148        rcu_assign_pointer(tfile->socket.wq, &tfile->wq);
2149        init_waitqueue_head(&tfile->wq.wait);
2150
2151        tfile->socket.file = file;
2152        tfile->socket.ops = &tun_socket_ops;
2153
2154        sock_init_data(&tfile->socket, &tfile->sk);
2155        sk_change_net(&tfile->sk, tfile->net);
2156
2157        tfile->sk.sk_write_space = tun_sock_write_space;
2158        tfile->sk.sk_sndbuf = INT_MAX;
2159
2160        file->private_data = tfile;
2161        set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
2162        INIT_LIST_HEAD(&tfile->next);
2163
2164        sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2165
2166        return 0;
2167}
2168
2169static int tun_chr_close(struct inode *inode, struct file *file)
2170{
2171        struct tun_file *tfile = file->private_data;
2172        struct net *net = tfile->net;
2173
2174        tun_detach(tfile, true);
2175        put_net(net);
2176
2177        return 0;
2178}
2179
2180static const struct file_operations tun_fops = {
2181        .owner  = THIS_MODULE,
2182        .llseek = no_llseek,
2183        .read  = do_sync_read,
2184        .aio_read  = tun_chr_aio_read,
2185        .write = do_sync_write,
2186        .aio_write = tun_chr_aio_write,
2187        .poll   = tun_chr_poll,
2188        .unlocked_ioctl = tun_chr_ioctl,
2189#ifdef CONFIG_COMPAT
2190        .compat_ioctl = tun_chr_compat_ioctl,
2191#endif
2192        .open   = tun_chr_open,
2193        .release = tun_chr_close,
2194        .fasync = tun_chr_fasync
2195};
2196
2197static struct miscdevice tun_miscdev = {
2198        .minor = TUN_MINOR,
2199        .name = "tun",
2200        .nodename = "net/tun",
2201        .fops = &tun_fops,
2202};
2203
2204/* ethtool interface */
2205
2206static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2207{
2208        cmd->supported          = 0;
2209        cmd->advertising        = 0;
2210        ethtool_cmd_speed_set(cmd, SPEED_10);
2211        cmd->duplex             = DUPLEX_FULL;
2212        cmd->port               = PORT_TP;
2213        cmd->phy_address        = 0;
2214        cmd->transceiver        = XCVR_INTERNAL;
2215        cmd->autoneg            = AUTONEG_DISABLE;
2216        cmd->maxtxpkt           = 0;
2217        cmd->maxrxpkt           = 0;
2218        return 0;
2219}
2220
2221static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2222{
2223        struct tun_struct *tun = netdev_priv(dev);
2224
2225        strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2226        strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2227
2228        switch (tun->flags & TUN_TYPE_MASK) {
2229        case TUN_TUN_DEV:
2230                strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2231                break;
2232        case TUN_TAP_DEV:
2233                strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2234                break;
2235        }
2236}
2237
2238static u32 tun_get_msglevel(struct net_device *dev)
2239{
2240#ifdef TUN_DEBUG
2241        struct tun_struct *tun = netdev_priv(dev);
2242        return tun->debug;
2243#else
2244        return -EOPNOTSUPP;
2245#endif
2246}
2247
2248static void tun_set_msglevel(struct net_device *dev, u32 value)
2249{
2250#ifdef TUN_DEBUG
2251        struct tun_struct *tun = netdev_priv(dev);
2252        tun->debug = value;
2253#endif
2254}
2255
2256static const struct ethtool_ops tun_ethtool_ops = {
2257        .get_settings   = tun_get_settings,
2258        .get_drvinfo    = tun_get_drvinfo,
2259        .get_msglevel   = tun_get_msglevel,
2260        .set_msglevel   = tun_set_msglevel,
2261        .get_link       = ethtool_op_get_link,
2262};
2263
2264
2265static int __init tun_init(void)
2266{
2267        int ret = 0;
2268
2269        pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2270        pr_info("%s\n", DRV_COPYRIGHT);
2271
2272        ret = rtnl_link_register(&tun_link_ops);
2273        if (ret) {
2274                pr_err("Can't register link_ops\n");
2275                goto err_linkops;
2276        }
2277
2278        ret = misc_register(&tun_miscdev);
2279        if (ret) {
2280                pr_err("Can't register misc device %d\n", TUN_MINOR);
2281                goto err_misc;
2282        }
2283        return  0;
2284err_misc:
2285        rtnl_link_unregister(&tun_link_ops);
2286err_linkops:
2287        return ret;
2288}
2289
2290static void tun_cleanup(void)
2291{
2292        misc_deregister(&tun_miscdev);
2293        rtnl_link_unregister(&tun_link_ops);
2294}
2295
2296/* Get an underlying socket object from tun file.  Returns error unless file is
2297 * attached to a device.  The returned object works like a packet socket, it
2298 * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2299 * holding a reference to the file for as long as the socket is in use. */
2300struct socket *tun_get_socket(struct file *file)
2301{
2302        struct tun_file *tfile;
2303        if (file->f_op != &tun_fops)
2304                return ERR_PTR(-EINVAL);
2305        tfile = file->private_data;
2306        if (!tfile)
2307                return ERR_PTR(-EBADFD);
2308        return &tfile->socket;
2309}
2310EXPORT_SYMBOL_GPL(tun_get_socket);
2311
2312module_init(tun_init);
2313module_exit(tun_cleanup);
2314MODULE_DESCRIPTION(DRV_DESCRIPTION);
2315MODULE_AUTHOR(DRV_COPYRIGHT);
2316MODULE_LICENSE("GPL");
2317MODULE_ALIAS_MISCDEV(TUN_MINOR);
2318MODULE_ALIAS("devname:net/tun");
2319
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