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/if_vlan.h>
  64#include <linux/crc32.h>
  65#include <linux/nsproxy.h>
  66#include <linux/virtio_net.h>
  67#include <linux/rcupdate.h>
  68#include <net/net_namespace.h>
  69#include <net/netns/generic.h>
  70#include <net/rtnetlink.h>
  71#include <net/sock.h>
  72
  73#include <asm/uaccess.h>
  74
  75/* Uncomment to enable debugging */
  76/* #define TUN_DEBUG 1 */
  77
  78#ifdef TUN_DEBUG
  79static int debug;
  80
  81#define tun_debug(level, tun, fmt, args...)                     \
  82do {                                                            \
  83        if (tun->debug)                                         \
  84                netdev_printk(level, tun->dev, fmt, ##args);    \
  85} while (0)
  86#define DBG1(level, fmt, args...)                               \
  87do {                                                            \
  88        if (debug == 2)                                         \
  89                printk(level fmt, ##args);                      \
  90} while (0)
  91#else
  92#define tun_debug(level, tun, fmt, args...)                     \
  93do {                                                            \
  94        if (0)                                                  \
  95                netdev_printk(level, tun->dev, fmt, ##args);    \
  96} while (0)
  97#define DBG1(level, fmt, args...)                               \
  98do {                                                            \
  99        if (0)                                                  \
 100                printk(level fmt, ##args);                      \
 101} while (0)
 102#endif
 103
 104#define GOODCOPY_LEN 128
 105
 106#define FLT_EXACT_COUNT 8
 107struct tap_filter {
 108        unsigned int    count;    /* Number of addrs. Zero means disabled */
 109        u32             mask[2];  /* Mask of the hashed addrs */
 110        unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 111};
 112
 113/* DEFAULT_MAX_NUM_RSS_QUEUES were choosed to let the rx/tx queues allocated for
 114 * the netdevice to be fit in one page. So we can make sure the success of
 115 * memory allocation. TODO: increase the limit. */
 116#define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES
 117#define MAX_TAP_FLOWS  4096
 118
 119#define TUN_FLOW_EXPIRE (3 * HZ)
 120
 121/* A tun_file connects an open character device to a tuntap netdevice. It
 122 * also contains all socket related strctures (except sock_fprog and tap_filter)
 123 * to serve as one transmit queue for tuntap device. The sock_fprog and
 124 * tap_filter were kept in tun_struct since they were used for filtering for the
 125 * netdevice not for a specific queue (at least I didn't see the requirement for
 126 * this).
 127 *
 128 * RCU usage:
 129 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
 130 * other can only be read while rcu_read_lock or rtnl_lock is held.
 131 */
 132struct tun_file {
 133        struct sock sk;
 134        struct socket socket;
 135        struct socket_wq wq;
 136        struct tun_struct __rcu *tun;
 137        struct net *net;
 138        struct fasync_struct *fasync;
 139        /* only used for fasnyc */
 140        unsigned int flags;
 141        union {
 142                u16 queue_index;
 143                unsigned int ifindex;
 144        };
 145        struct list_head next;
 146        struct tun_struct *detached;
 147};
 148
 149struct tun_flow_entry {
 150        struct hlist_node hash_link;
 151        struct rcu_head rcu;
 152        struct tun_struct *tun;
 153
 154        u32 rxhash;
 155        int queue_index;
 156        unsigned long updated;
 157};
 158
 159#define TUN_NUM_FLOW_ENTRIES 1024
 160
 161/* Since the socket were moved to tun_file, to preserve the behavior of persist
 162 * device, socket filter, sndbuf and vnet header size were restore when the
 163 * file were attached to a persist device.
 164 */
 165struct tun_struct {
 166        struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
 167        unsigned int            numqueues;
 168        unsigned int            flags;
 169        kuid_t                  owner;
 170        kgid_t                  group;
 171
 172        struct net_device       *dev;
 173        netdev_features_t       set_features;
 174#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 175                          NETIF_F_TSO6|NETIF_F_UFO)
 176
 177        int                     vnet_hdr_sz;
 178        int                     sndbuf;
 179        struct tap_filter       txflt;
 180        struct sock_fprog       fprog;
 181        /* protected by rtnl lock */
 182        bool                    filter_attached;
 183#ifdef TUN_DEBUG
 184        int debug;
 185#endif
 186        spinlock_t lock;
 187        struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 188        struct timer_list flow_gc_timer;
 189        unsigned long ageing_time;
 190        unsigned int numdisabled;
 191        struct list_head disabled;
 192        void *security;
 193        u32 flow_count;
 194};
 195
 196static inline u32 tun_hashfn(u32 rxhash)
 197{
 198        return rxhash & 0x3ff;
 199}
 200
 201static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 202{
 203        struct tun_flow_entry *e;
 204
 205        hlist_for_each_entry_rcu(e, head, hash_link) {
 206                if (e->rxhash == rxhash)
 207                        return e;
 208        }
 209        return NULL;
 210}
 211
 212static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 213                                              struct hlist_head *head,
 214                                              u32 rxhash, u16 queue_index)
 215{
 216        struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 217
 218        if (e) {
 219                tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 220                          rxhash, queue_index);
 221                e->updated = jiffies;
 222                e->rxhash = rxhash;
 223                e->queue_index = queue_index;
 224                e->tun = tun;
 225                hlist_add_head_rcu(&e->hash_link, head);
 226                ++tun->flow_count;
 227        }
 228        return e;
 229}
 230
 231static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 232{
 233        tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 234                  e->rxhash, e->queue_index);
 235        hlist_del_rcu(&e->hash_link);
 236        kfree_rcu(e, rcu);
 237        --tun->flow_count;
 238}
 239
 240static void tun_flow_flush(struct tun_struct *tun)
 241{
 242        int i;
 243
 244        spin_lock_bh(&tun->lock);
 245        for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 246                struct tun_flow_entry *e;
 247                struct hlist_node *n;
 248
 249                hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 250                        tun_flow_delete(tun, e);
 251        }
 252        spin_unlock_bh(&tun->lock);
 253}
 254
 255static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 256{
 257        int i;
 258
 259        spin_lock_bh(&tun->lock);
 260        for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 261                struct tun_flow_entry *e;
 262                struct hlist_node *n;
 263
 264                hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 265                        if (e->queue_index == queue_index)
 266                                tun_flow_delete(tun, e);
 267                }
 268        }
 269        spin_unlock_bh(&tun->lock);
 270}
 271
 272static void tun_flow_cleanup(unsigned long data)
 273{
 274        struct tun_struct *tun = (struct tun_struct *)data;
 275        unsigned long delay = tun->ageing_time;
 276        unsigned long next_timer = jiffies + delay;
 277        unsigned long count = 0;
 278        int i;
 279
 280        tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 281
 282        spin_lock_bh(&tun->lock);
 283        for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 284                struct tun_flow_entry *e;
 285                struct hlist_node *n;
 286
 287                hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 288                        unsigned long this_timer;
 289                        count++;
 290                        this_timer = e->updated + delay;
 291                        if (time_before_eq(this_timer, jiffies))
 292                                tun_flow_delete(tun, e);
 293                        else if (time_before(this_timer, next_timer))
 294                                next_timer = this_timer;
 295                }
 296        }
 297
 298        if (count)
 299                mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 300        spin_unlock_bh(&tun->lock);
 301}
 302
 303static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 304                            struct tun_file *tfile)
 305{
 306        struct hlist_head *head;
 307        struct tun_flow_entry *e;
 308        unsigned long delay = tun->ageing_time;
 309        u16 queue_index = tfile->queue_index;
 310
 311        if (!rxhash)
 312                return;
 313        else
 314                head = &tun->flows[tun_hashfn(rxhash)];
 315
 316        rcu_read_lock();
 317
 318        /* We may get a very small possibility of OOO during switching, not
 319         * worth to optimize.*/
 320        if (tun->numqueues == 1 || tfile->detached)
 321                goto unlock;
 322
 323        e = tun_flow_find(head, rxhash);
 324        if (likely(e)) {
 325                /* TODO: keep queueing to old queue until it's empty? */
 326                e->queue_index = queue_index;
 327                e->updated = jiffies;
 328        } else {
 329                spin_lock_bh(&tun->lock);
 330                if (!tun_flow_find(head, rxhash) &&
 331                    tun->flow_count < MAX_TAP_FLOWS)
 332                        tun_flow_create(tun, head, rxhash, queue_index);
 333
 334                if (!timer_pending(&tun->flow_gc_timer))
 335                        mod_timer(&tun->flow_gc_timer,
 336                                  round_jiffies_up(jiffies + delay));
 337                spin_unlock_bh(&tun->lock);
 338        }
 339
 340unlock:
 341        rcu_read_unlock();
 342}
 343
 344/* We try to identify a flow through its rxhash first. The reason that
 345 * we do not check rxq no. is becuase some cards(e.g 82599), chooses
 346 * the rxq based on the txq where the last packet of the flow comes. As
 347 * the userspace application move between processors, we may get a
 348 * different rxq no. here. If we could not get rxhash, then we would
 349 * hope the rxq no. may help here.
 350 */
 351static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb)
 352{
 353        struct tun_struct *tun = netdev_priv(dev);
 354        struct tun_flow_entry *e;
 355        u32 txq = 0;
 356        u32 numqueues = 0;
 357
 358        rcu_read_lock();
 359        numqueues = ACCESS_ONCE(tun->numqueues);
 360
 361        txq = skb_get_rxhash(skb);
 362        if (txq) {
 363                e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 364                if (e)
 365                        txq = e->queue_index;
 366                else
 367                        /* use multiply and shift instead of expensive divide */
 368                        txq = ((u64)txq * numqueues) >> 32;
 369        } else if (likely(skb_rx_queue_recorded(skb))) {
 370                txq = skb_get_rx_queue(skb);
 371                while (unlikely(txq >= numqueues))
 372                        txq -= numqueues;
 373        }
 374
 375        rcu_read_unlock();
 376        return txq;
 377}
 378
 379static inline bool tun_not_capable(struct tun_struct *tun)
 380{
 381        const struct cred *cred = current_cred();
 382        struct net *net = dev_net(tun->dev);
 383
 384        return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 385                  (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 386                !ns_capable(net->user_ns, CAP_NET_ADMIN);
 387}
 388
 389static void tun_set_real_num_queues(struct tun_struct *tun)
 390{
 391        netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 392        netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 393}
 394
 395static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 396{
 397        tfile->detached = tun;
 398        list_add_tail(&tfile->next, &tun->disabled);
 399        ++tun->numdisabled;
 400}
 401
 402static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 403{
 404        struct tun_struct *tun = tfile->detached;
 405
 406        tfile->detached = NULL;
 407        list_del_init(&tfile->next);
 408        --tun->numdisabled;
 409        return tun;
 410}
 411
 412static void tun_queue_purge(struct tun_file *tfile)
 413{
 414        skb_queue_purge(&tfile->sk.sk_receive_queue);
 415        skb_queue_purge(&tfile->sk.sk_error_queue);
 416}
 417
 418static void __tun_detach(struct tun_file *tfile, bool clean)
 419{
 420        struct tun_file *ntfile;
 421        struct tun_struct *tun;
 422
 423        tun = rtnl_dereference(tfile->tun);
 424
 425        if (tun && !tfile->detached) {
 426                u16 index = tfile->queue_index;
 427                BUG_ON(index >= tun->numqueues);
 428
 429                rcu_assign_pointer(tun->tfiles[index],
 430                                   tun->tfiles[tun->numqueues - 1]);
 431                ntfile = rtnl_dereference(tun->tfiles[index]);
 432                ntfile->queue_index = index;
 433
 434                --tun->numqueues;
 435                if (clean) {
 436                        rcu_assign_pointer(tfile->tun, NULL);
 437                        sock_put(&tfile->sk);
 438                } else
 439                        tun_disable_queue(tun, tfile);
 440
 441                synchronize_net();
 442                tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 443                /* Drop read queue */
 444                tun_queue_purge(tfile);
 445                tun_set_real_num_queues(tun);
 446        } else if (tfile->detached && clean) {
 447                tun = tun_enable_queue(tfile);
 448                sock_put(&tfile->sk);
 449        }
 450
 451        if (clean) {
 452                if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 453                        netif_carrier_off(tun->dev);
 454
 455                        if (!(tun->flags & TUN_PERSIST) &&
 456                            tun->dev->reg_state == NETREG_REGISTERED)
 457                                unregister_netdevice(tun->dev);
 458                }
 459
 460                BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
 461                                 &tfile->socket.flags));
 462                sk_release_kernel(&tfile->sk);
 463        }
 464}
 465
 466static void tun_detach(struct tun_file *tfile, bool clean)
 467{
 468        rtnl_lock();
 469        __tun_detach(tfile, clean);
 470        rtnl_unlock();
 471}
 472
 473static void tun_detach_all(struct net_device *dev)
 474{
 475        struct tun_struct *tun = netdev_priv(dev);
 476        struct tun_file *tfile, *tmp;
 477        int i, n = tun->numqueues;
 478
 479        for (i = 0; i < n; i++) {
 480                tfile = rtnl_dereference(tun->tfiles[i]);
 481                BUG_ON(!tfile);
 482                wake_up_all(&tfile->wq.wait);
 483                rcu_assign_pointer(tfile->tun, NULL);
 484                --tun->numqueues;
 485        }
 486        list_for_each_entry(tfile, &tun->disabled, next) {
 487                wake_up_all(&tfile->wq.wait);
 488                rcu_assign_pointer(tfile->tun, NULL);
 489        }
 490        BUG_ON(tun->numqueues != 0);
 491
 492        synchronize_net();
 493        for (i = 0; i < n; i++) {
 494                tfile = rtnl_dereference(tun->tfiles[i]);
 495                /* Drop read queue */
 496                tun_queue_purge(tfile);
 497                sock_put(&tfile->sk);
 498        }
 499        list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 500                tun_enable_queue(tfile);
 501                tun_queue_purge(tfile);
 502                sock_put(&tfile->sk);
 503        }
 504        BUG_ON(tun->numdisabled != 0);
 505
 506        if (tun->flags & TUN_PERSIST)
 507                module_put(THIS_MODULE);
 508}
 509
 510static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
 511{
 512        struct tun_file *tfile = file->private_data;
 513        int err;
 514
 515        err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 516        if (err < 0)
 517                goto out;
 518
 519        err = -EINVAL;
 520        if (rtnl_dereference(tfile->tun) && !tfile->detached)
 521                goto out;
 522
 523        err = -EBUSY;
 524        if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1)
 525                goto out;
 526
 527        err = -E2BIG;
 528        if (!tfile->detached &&
 529            tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 530                goto out;
 531
 532        err = 0;
 533
 534        /* Re-attach the filter to presist device */
 535        if (!skip_filter && (tun->filter_attached == true)) {
 536                err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 537                if (!err)
 538                        goto out;
 539        }
 540        tfile->queue_index = tun->numqueues;
 541        rcu_assign_pointer(tfile->tun, tun);
 542        rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 543        tun->numqueues++;
 544
 545        if (tfile->detached)
 546                tun_enable_queue(tfile);
 547        else
 548                sock_hold(&tfile->sk);
 549
 550        tun_set_real_num_queues(tun);
 551
 552        /* device is allowed to go away first, so no need to hold extra
 553         * refcnt.
 554         */
 555
 556out:
 557        return err;
 558}
 559
 560static struct tun_struct *__tun_get(struct tun_file *tfile)
 561{
 562        struct tun_struct *tun;
 563
 564        rcu_read_lock();
 565        tun = rcu_dereference(tfile->tun);
 566        if (tun)
 567                dev_hold(tun->dev);
 568        rcu_read_unlock();
 569
 570        return tun;
 571}
 572
 573static struct tun_struct *tun_get(struct file *file)
 574{
 575        return __tun_get(file->private_data);
 576}
 577
 578static void tun_put(struct tun_struct *tun)
 579{
 580        dev_put(tun->dev);
 581}
 582
 583/* TAP filtering */
 584static void addr_hash_set(u32 *mask, const u8 *addr)
 585{
 586        int n = ether_crc(ETH_ALEN, addr) >> 26;
 587        mask[n >> 5] |= (1 << (n & 31));
 588}
 589
 590static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 591{
 592        int n = ether_crc(ETH_ALEN, addr) >> 26;
 593        return mask[n >> 5] & (1 << (n & 31));
 594}
 595
 596static int update_filter(struct tap_filter *filter, void __user *arg)
 597{
 598        struct { u8 u[ETH_ALEN]; } *addr;
 599        struct tun_filter uf;
 600        int err, alen, n, nexact;
 601
 602        if (copy_from_user(&uf, arg, sizeof(uf)))
 603                return -EFAULT;
 604
 605        if (!uf.count) {
 606                /* Disabled */
 607                filter->count = 0;
 608                return 0;
 609        }
 610
 611        alen = ETH_ALEN * uf.count;
 612        addr = kmalloc(alen, GFP_KERNEL);
 613        if (!addr)
 614                return -ENOMEM;
 615
 616        if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 617                err = -EFAULT;
 618                goto done;
 619        }
 620
 621        /* The filter is updated without holding any locks. Which is
 622         * perfectly safe. We disable it first and in the worst
 623         * case we'll accept a few undesired packets. */
 624        filter->count = 0;
 625        wmb();
 626
 627        /* Use first set of addresses as an exact filter */
 628        for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 629                memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 630
 631        nexact = n;
 632
 633        /* Remaining multicast addresses are hashed,
 634         * unicast will leave the filter disabled. */
 635        memset(filter->mask, 0, sizeof(filter->mask));
 636        for (; n < uf.count; n++) {
 637                if (!is_multicast_ether_addr(addr[n].u)) {
 638                        err = 0; /* no filter */
 639                        goto done;
 640                }
 641                addr_hash_set(filter->mask, addr[n].u);
 642        }
 643
 644        /* For ALLMULTI just set the mask to all ones.
 645         * This overrides the mask populated above. */
 646        if ((uf.flags & TUN_FLT_ALLMULTI))
 647                memset(filter->mask, ~0, sizeof(filter->mask));
 648
 649        /* Now enable the filter */
 650        wmb();
 651        filter->count = nexact;
 652
 653        /* Return the number of exact filters */
 654        err = nexact;
 655
 656done:
 657        kfree(addr);
 658        return err;
 659}
 660
 661/* Returns: 0 - drop, !=0 - accept */
 662static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 663{
 664        /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 665         * at this point. */
 666        struct ethhdr *eh = (struct ethhdr *) skb->data;
 667        int i;
 668
 669        /* Exact match */
 670        for (i = 0; i < filter->count; i++)
 671                if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 672                        return 1;
 673
 674        /* Inexact match (multicast only) */
 675        if (is_multicast_ether_addr(eh->h_dest))
 676                return addr_hash_test(filter->mask, eh->h_dest);
 677
 678        return 0;
 679}
 680
 681/*
 682 * Checks whether the packet is accepted or not.
 683 * Returns: 0 - drop, !=0 - accept
 684 */
 685static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 686{
 687        if (!filter->count)
 688                return 1;
 689
 690        return run_filter(filter, skb);
 691}
 692
 693/* Network device part of the driver */
 694
 695static const struct ethtool_ops tun_ethtool_ops;
 696
 697/* Net device detach from fd. */
 698static void tun_net_uninit(struct net_device *dev)
 699{
 700        tun_detach_all(dev);
 701}
 702
 703/* Net device open. */
 704static int tun_net_open(struct net_device *dev)
 705{
 706        netif_tx_start_all_queues(dev);
 707        return 0;
 708}
 709
 710/* Net device close. */
 711static int tun_net_close(struct net_device *dev)
 712{
 713        netif_tx_stop_all_queues(dev);
 714        return 0;
 715}
 716
 717/* Net device start xmit */
 718static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 719{
 720        struct tun_struct *tun = netdev_priv(dev);
 721        int txq = skb->queue_mapping;
 722        struct tun_file *tfile;
 723
 724        rcu_read_lock();
 725        tfile = rcu_dereference(tun->tfiles[txq]);
 726
 727        /* Drop packet if interface is not attached */
 728        if (txq >= tun->numqueues)
 729                goto drop;
 730
 731        tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 732
 733        BUG_ON(!tfile);
 734
 735        /* Drop if the filter does not like it.
 736         * This is a noop if the filter is disabled.
 737         * Filter can be enabled only for the TAP devices. */
 738        if (!check_filter(&tun->txflt, skb))
 739                goto drop;
 740
 741        if (tfile->socket.sk->sk_filter &&
 742            sk_filter(tfile->socket.sk, skb))
 743                goto drop;
 744
 745        /* Limit the number of packets queued by dividing txq length with the
 746         * number of queues.
 747         */
 748        if (skb_queue_len(&tfile->socket.sk->sk_receive_queue)
 749                          >= dev->tx_queue_len / tun->numqueues)
 750                goto drop;
 751
 752        if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 753                goto drop;
 754
 755        if (skb->sk) {
 756                sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags);
 757                sw_tx_timestamp(skb);
 758        }
 759
 760        /* Orphan the skb - required as we might hang on to it
 761         * for indefinite time.
 762         */
 763        skb_orphan(skb);
 764
 765        nf_reset(skb);
 766
 767        /* Enqueue packet */
 768        skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
 769
 770        /* Notify and wake up reader process */
 771        if (tfile->flags & TUN_FASYNC)
 772                kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
 773        wake_up_interruptible_poll(&tfile->wq.wait, POLLIN |
 774                                   POLLRDNORM | POLLRDBAND);
 775
 776        rcu_read_unlock();
 777        return NETDEV_TX_OK;
 778
 779drop:
 780        dev->stats.tx_dropped++;
 781        skb_tx_error(skb);
 782        kfree_skb(skb);
 783        rcu_read_unlock();
 784        return NETDEV_TX_OK;
 785}
 786
 787static void tun_net_mclist(struct net_device *dev)
 788{
 789        /*
 790         * This callback is supposed to deal with mc filter in
 791         * _rx_ path and has nothing to do with the _tx_ path.
 792         * In rx path we always accept everything userspace gives us.
 793         */
 794}
 795
 796#define MIN_MTU 68
 797#define MAX_MTU 65535
 798
 799static int
 800tun_net_change_mtu(struct net_device *dev, int new_mtu)
 801{
 802        if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 803                return -EINVAL;
 804        dev->mtu = new_mtu;
 805        return 0;
 806}
 807
 808static netdev_features_t tun_net_fix_features(struct net_device *dev,
 809        netdev_features_t features)
 810{
 811        struct tun_struct *tun = netdev_priv(dev);
 812
 813        return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 814}
 815#ifdef CONFIG_NET_POLL_CONTROLLER
 816static void tun_poll_controller(struct net_device *dev)
 817{
 818        /*
 819         * Tun only receives frames when:
 820         * 1) the char device endpoint gets data from user space
 821         * 2) the tun socket gets a sendmsg call from user space
 822         * Since both of those are syncronous operations, we are guaranteed
 823         * never to have pending data when we poll for it
 824         * so theres nothing to do here but return.
 825         * We need this though so netpoll recognizes us as an interface that
 826         * supports polling, which enables bridge devices in virt setups to
 827         * still use netconsole
 828         */
 829        return;
 830}
 831#endif
 832static const struct net_device_ops tun_netdev_ops = {
 833        .ndo_uninit             = tun_net_uninit,
 834        .ndo_open               = tun_net_open,
 835        .ndo_stop               = tun_net_close,
 836        .ndo_start_xmit         = tun_net_xmit,
 837        .ndo_change_mtu         = tun_net_change_mtu,
 838        .ndo_fix_features       = tun_net_fix_features,
 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 const struct net_device_ops tap_netdev_ops = {
 846        .ndo_uninit             = tun_net_uninit,
 847        .ndo_open               = tun_net_open,
 848        .ndo_stop               = tun_net_close,
 849        .ndo_start_xmit         = tun_net_xmit,
 850        .ndo_change_mtu         = tun_net_change_mtu,
 851        .ndo_fix_features       = tun_net_fix_features,
 852        .ndo_set_rx_mode        = tun_net_mclist,
 853        .ndo_set_mac_address    = eth_mac_addr,
 854        .ndo_validate_addr      = eth_validate_addr,
 855        .ndo_select_queue       = tun_select_queue,
 856#ifdef CONFIG_NET_POLL_CONTROLLER
 857        .ndo_poll_controller    = tun_poll_controller,
 858#endif
 859};
 860
 861static void tun_flow_init(struct tun_struct *tun)
 862{
 863        int i;
 864
 865        for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
 866                INIT_HLIST_HEAD(&tun->flows[i]);
 867
 868        tun->ageing_time = TUN_FLOW_EXPIRE;
 869        setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
 870        mod_timer(&tun->flow_gc_timer,
 871                  round_jiffies_up(jiffies + tun->ageing_time));
 872}
 873
 874static void tun_flow_uninit(struct tun_struct *tun)
 875{
 876        del_timer_sync(&tun->flow_gc_timer);
 877        tun_flow_flush(tun);
 878}
 879
 880/* Initialize net device. */
 881static void tun_net_init(struct net_device *dev)
 882{
 883        struct tun_struct *tun = netdev_priv(dev);
 884
 885        switch (tun->flags & TUN_TYPE_MASK) {
 886        case TUN_TUN_DEV:
 887                dev->netdev_ops = &tun_netdev_ops;
 888
 889                /* Point-to-Point TUN Device */
 890                dev->hard_header_len = 0;
 891                dev->addr_len = 0;
 892                dev->mtu = 1500;
 893
 894                /* Zero header length */
 895                dev->type = ARPHRD_NONE;
 896                dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 897                dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 898                break;
 899
 900        case TUN_TAP_DEV:
 901                dev->netdev_ops = &tap_netdev_ops;
 902                /* Ethernet TAP Device */
 903                ether_setup(dev);
 904                dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 905                dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
 906
 907                eth_hw_addr_random(dev);
 908
 909                dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 910                break;
 911        }
 912}
 913
 914/* Character device part */
 915
 916/* Poll */
 917static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
 918{
 919        struct tun_file *tfile = file->private_data;
 920        struct tun_struct *tun = __tun_get(tfile);
 921        struct sock *sk;
 922        unsigned int mask = 0;
 923
 924        if (!tun)
 925                return POLLERR;
 926
 927        sk = tfile->socket.sk;
 928
 929        tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
 930
 931        poll_wait(file, &tfile->wq.wait, wait);
 932
 933        if (!skb_queue_empty(&sk->sk_receive_queue))
 934                mask |= POLLIN | POLLRDNORM;
 935
 936        if (sock_writeable(sk) ||
 937            (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 938             sock_writeable(sk)))
 939                mask |= POLLOUT | POLLWRNORM;
 940
 941        if (tun->dev->reg_state != NETREG_REGISTERED)
 942                mask = POLLERR;
 943
 944        tun_put(tun);
 945        return mask;
 946}
 947
 948/* prepad is the amount to reserve at front.  len is length after that.
 949 * linear is a hint as to how much to copy (usually headers). */
 950static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
 951                                     size_t prepad, size_t len,
 952                                     size_t linear, int noblock)
 953{
 954        struct sock *sk = tfile->socket.sk;
 955        struct sk_buff *skb;
 956        int err;
 957
 958        /* Under a page?  Don't bother with paged skb. */
 959        if (prepad + len < PAGE_SIZE || !linear)
 960                linear = len;
 961
 962        skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 963                                   &err, 0);
 964        if (!skb)
 965                return ERR_PTR(err);
 966
 967        skb_reserve(skb, prepad);
 968        skb_put(skb, linear);
 969        skb->data_len = len - linear;
 970        skb->len += len - linear;
 971
 972        return skb;
 973}
 974
 975/* Get packet from user space buffer */
 976static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 977                            void *msg_control, const struct iovec *iv,
 978                            size_t total_len, size_t count, int noblock)
 979{
 980        struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
 981        struct sk_buff *skb;
 982        size_t len = total_len, align = NET_SKB_PAD, linear;
 983        struct virtio_net_hdr gso = { 0 };
 984        int offset = 0;
 985        int copylen;
 986        bool zerocopy = false;
 987        int err;
 988        u32 rxhash;
 989
 990        if (!(tun->flags & TUN_NO_PI)) {
 991                if (len < sizeof(pi))
 992                        return -EINVAL;
 993                len -= sizeof(pi);
 994
 995                if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
 996                        return -EFAULT;
 997                offset += sizeof(pi);
 998        }
 999
1000        if (tun->flags & TUN_VNET_HDR) {
1001                if (len < tun->vnet_hdr_sz)
1002                        return -EINVAL;
1003                len -= tun->vnet_hdr_sz;
1004
1005                if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
1006                        return -EFAULT;
1007
1008                if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1009                    gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
1010                        gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
1011
1012                if (gso.hdr_len > len)
1013                        return -EINVAL;
1014                offset += tun->vnet_hdr_sz;
1015        }
1016
1017        if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
1018                align += NET_IP_ALIGN;
1019                if (unlikely(len < ETH_HLEN ||
1020                             (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
1021                        return -EINVAL;
1022        }
1023
1024        if (msg_control) {
1025                /* There are 256 bytes to be copied in skb, so there is
1026                 * enough room for skb expand head in case it is used.
1027                 * The rest of the buffer is mapped from userspace.
1028                 */
1029                copylen = gso.hdr_len ? gso.hdr_len : GOODCOPY_LEN;
1030                linear = copylen;
1031                if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS)
1032                        zerocopy = true;
1033        }
1034
1035        if (!zerocopy) {
1036                copylen = len;
1037                linear = gso.hdr_len;
1038        }
1039
1040        skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1041        if (IS_ERR(skb)) {
1042                if (PTR_ERR(skb) != -EAGAIN)
1043                        tun->dev->stats.rx_dropped++;
1044                return PTR_ERR(skb);
1045        }
1046
1047        if (zerocopy)
1048                err = zerocopy_sg_from_iovec(skb, iv, offset, count);
1049        else {
1050                err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
1051                if (!err && msg_control) {
1052                        struct ubuf_info *uarg = msg_control;
1053                        uarg->callback(uarg, false);
1054                }
1055        }
1056
1057        if (err) {
1058                tun->dev->stats.rx_dropped++;
1059                kfree_skb(skb);
1060                return -EFAULT;
1061        }
1062
1063        if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1064                if (!skb_partial_csum_set(skb, gso.csum_start,
1065                                          gso.csum_offset)) {
1066                        tun->dev->stats.rx_frame_errors++;
1067                        kfree_skb(skb);
1068                        return -EINVAL;
1069                }
1070        }
1071
1072        switch (tun->flags & TUN_TYPE_MASK) {
1073        case TUN_TUN_DEV:
1074                if (tun->flags & TUN_NO_PI) {
1075                        switch (skb->data[0] & 0xf0) {
1076                        case 0x40:
1077                                pi.proto = htons(ETH_P_IP);
1078                                break;
1079                        case 0x60:
1080                                pi.proto = htons(ETH_P_IPV6);
1081                                break;
1082                        default:
1083                                tun->dev->stats.rx_dropped++;
1084                                kfree_skb(skb);
1085                                return -EINVAL;
1086                        }
1087                }
1088
1089                skb_reset_mac_header(skb);
1090                skb->protocol = pi.proto;
1091                skb->dev = tun->dev;
1092                break;
1093        case TUN_TAP_DEV:
1094                skb->protocol = eth_type_trans(skb, tun->dev);
1095                break;
1096        }
1097
1098        if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1099                pr_debug("GSO!\n");
1100                switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1101                case VIRTIO_NET_HDR_GSO_TCPV4:
1102                        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1103                        break;
1104                case VIRTIO_NET_HDR_GSO_TCPV6:
1105                        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1106                        break;
1107                case VIRTIO_NET_HDR_GSO_UDP:
1108                        skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1109                        break;
1110                default:
1111                        tun->dev->stats.rx_frame_errors++;
1112                        kfree_skb(skb);
1113                        return -EINVAL;
1114                }
1115
1116                if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1117                        skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1118
1119                skb_shinfo(skb)->gso_size = gso.gso_size;
1120                if (skb_shinfo(skb)->gso_size == 0) {
1121                        tun->dev->stats.rx_frame_errors++;
1122                        kfree_skb(skb);
1123                        return -EINVAL;
1124                }
1125
1126                /* Header must be checked, and gso_segs computed. */
1127                skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1128                skb_shinfo(skb)->gso_segs = 0;
1129        }
1130
1131        /* copy skb_ubuf_info for callback when skb has no error */
1132        if (zerocopy) {
1133                skb_shinfo(skb)->destructor_arg = msg_control;
1134                skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1135                skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1136        }
1137
1138        skb_reset_network_header(skb);
1139        skb_probe_transport_header(skb, 0);
1140
1141        rxhash = skb_get_rxhash(skb);
1142        netif_rx_ni(skb);
1143
1144        tun->dev->stats.rx_packets++;
1145        tun->dev->stats.rx_bytes += len;
1146
1147        tun_flow_update(tun, rxhash, tfile);
1148        return total_len;
1149}
1150
1151static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
1152                              unsigned long count, loff_t pos)
1153{
1154        struct file *file = iocb->ki_filp;
1155        struct tun_struct *tun = tun_get(file);
1156        struct tun_file *tfile = file->private_data;
1157        ssize_t result;
1158
1159        if (!tun)
1160                return -EBADFD;
1161
1162        tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
1163
1164        result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count),
1165                              count, file->f_flags & O_NONBLOCK);
1166
1167        tun_put(tun);
1168        return result;
1169}
1170
1171/* Put packet to the user space buffer */
1172static ssize_t tun_put_user(struct tun_struct *tun,
1173                            struct tun_file *tfile,
1174                            struct sk_buff *skb,
1175                            const struct iovec *iv, int len)
1176{
1177        struct tun_pi pi = { 0, skb->protocol };
1178        ssize_t total = 0;
1179        int vlan_offset = 0;
1180
1181        if (!(tun->flags & TUN_NO_PI)) {
1182                if ((len -= sizeof(pi)) < 0)
1183                        return -EINVAL;
1184
1185                if (len < skb->len) {
1186                        /* Packet will be striped */
1187                        pi.flags |= TUN_PKT_STRIP;
1188                }
1189
1190                if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
1191                        return -EFAULT;
1192                total += sizeof(pi);
1193        }
1194
1195        if (tun->flags & TUN_VNET_HDR) {
1196                struct virtio_net_hdr gso = { 0 }; /* no info leak */
1197                if ((len -= tun->vnet_hdr_sz) < 0)
1198                        return -EINVAL;
1199
1200                if (skb_is_gso(skb)) {
1201                        struct skb_shared_info *sinfo = skb_shinfo(skb);
1202
1203                        /* This is a hint as to how much should be linear. */
1204                        gso.hdr_len = skb_headlen(skb);
1205                        gso.gso_size = sinfo->gso_size;
1206                        if (sinfo->gso_type & SKB_GSO_TCPV4)
1207                                gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1208                        else if (sinfo->gso_type & SKB_GSO_TCPV6)
1209                                gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1210                        else if (sinfo->gso_type & SKB_GSO_UDP)
1211                                gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1212                        else {
1213                                pr_err("unexpected GSO type: "
1214                                       "0x%x, gso_size %d, hdr_len %d\n",
1215                                       sinfo->gso_type, gso.gso_size,
1216                                       gso.hdr_len);
1217                                print_hex_dump(KERN_ERR, "tun: ",
1218                                               DUMP_PREFIX_NONE,
1219                                               16, 1, skb->head,
1220                                               min((int)gso.hdr_len, 64), true);
1221                                WARN_ON_ONCE(1);
1222                                return -EINVAL;
1223                        }
1224                        if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1225                                gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1226                } else
1227                        gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1228
1229                if (skb->ip_summed == CHECKSUM_PARTIAL) {
1230                        gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1231                        gso.csum_start = skb_checksum_start_offset(skb);
1232                        gso.csum_offset = skb->csum_offset;
1233                } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1234                        gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1235                } /* else everything is zero */
1236
1237                if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
1238                                               sizeof(gso))))
1239                        return -EFAULT;
1240                total += tun->vnet_hdr_sz;
1241        }
1242
1243        if (!vlan_tx_tag_present(skb)) {
1244                len = min_t(int, skb->len, len);
1245        } else {
1246                int copy, ret;
1247                struct {
1248                        __be16 h_vlan_proto;
1249                        __be16 h_vlan_TCI;
1250                } veth;
1251
1252                veth.h_vlan_proto = skb->vlan_proto;
1253                veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb));
1254
1255                vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1256                len = min_t(int, skb->len + VLAN_HLEN, len);
1257
1258                copy = min_t(int, vlan_offset, len);
1259                ret = skb_copy_datagram_const_iovec(skb, 0, iv, total, copy);
1260                len -= copy;
1261                total += copy;
1262                if (ret || !len)
1263                        goto done;
1264
1265                copy = min_t(int, sizeof(veth), len);
1266                ret = memcpy_toiovecend(iv, (void *)&veth, total, copy);
1267                len -= copy;
1268                total += copy;
1269                if (ret || !len)
1270                        goto done;
1271        }
1272
1273        skb_copy_datagram_const_iovec(skb, vlan_offset, iv, total, len);
1274        total += len;
1275
1276done:
1277        tun->dev->stats.tx_packets++;
1278        tun->dev->stats.tx_bytes += len;
1279
1280        return total;
1281}
1282
1283static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1284                           struct kiocb *iocb, const struct iovec *iv,
1285                           ssize_t len, int noblock)
1286{
1287        DECLARE_WAITQUEUE(wait, current);
1288        struct sk_buff *skb;
1289        ssize_t ret = 0;
1290
1291        tun_debug(KERN_INFO, tun, "tun_do_read\n");
1292
1293        if (unlikely(!noblock))
1294                add_wait_queue(&tfile->wq.wait, &wait);
1295        while (len) {
1296                if (unlikely(!noblock))
1297                        current->state = TASK_INTERRUPTIBLE;
1298
1299                /* Read frames from the queue */
1300                if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) {
1301                        if (noblock) {
1302                                ret = -EAGAIN;
1303                                break;
1304                        }
1305                        if (signal_pending(current)) {
1306                                ret = -ERESTARTSYS;
1307                                break;
1308                        }
1309                        if (tun->dev->reg_state != NETREG_REGISTERED) {
1310                                ret = -EIO;
1311                                break;
1312                        }
1313
1314                        /* Nothing to read, let's sleep */
1315                        schedule();
1316                        continue;
1317                }
1318
1319                ret = tun_put_user(tun, tfile, skb, iv, len);
1320                kfree_skb(skb);
1321                break;
1322        }
1323
1324        if (unlikely(!noblock)) {
1325                current->state = TASK_RUNNING;
1326                remove_wait_queue(&tfile->wq.wait, &wait);
1327        }
1328
1329        return ret;
1330}
1331
1332static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1333                            unsigned long count, loff_t pos)
1334{
1335        struct file *file = iocb->ki_filp;
1336        struct tun_file *tfile = file->private_data;
1337        struct tun_struct *tun = __tun_get(tfile);
1338        ssize_t len, ret;
1339
1340        if (!tun)
1341                return -EBADFD;
1342        len = iov_length(iv, count);
1343        if (len < 0) {
1344                ret = -EINVAL;
1345                goto out;
1346        }
1347
1348        ret = tun_do_read(tun, tfile, iocb, iv, len,
1349                          file->f_flags & O_NONBLOCK);
1350        ret = min_t(ssize_t, ret, len);
1351out:
1352        tun_put(tun);
1353        return ret;
1354}
1355
1356static void tun_free_netdev(struct net_device *dev)
1357{
1358        struct tun_struct *tun = netdev_priv(dev);
1359
1360        BUG_ON(!(list_empty(&tun->disabled)));
1361        tun_flow_uninit(tun);
1362        security_tun_dev_free_security(tun->security);
1363        free_netdev(dev);
1364}
1365
1366static void tun_setup(struct net_device *dev)
1367{
1368        struct tun_struct *tun = netdev_priv(dev);
1369
1370        tun->owner = INVALID_UID;
1371        tun->group = INVALID_GID;
1372
1373        dev->ethtool_ops = &tun_ethtool_ops;
1374        dev->destructor = tun_free_netdev;
1375}
1376
1377/* Trivial set of netlink ops to allow deleting tun or tap
1378 * device with netlink.
1379 */
1380static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1381{
1382        return -EINVAL;
1383}
1384
1385static struct rtnl_link_ops tun_link_ops __read_mostly = {
1386        .kind           = DRV_NAME,
1387        .priv_size      = sizeof(struct tun_struct),
1388        .setup          = tun_setup,
1389        .validate       = tun_validate,
1390};
1391
1392static void tun_sock_write_space(struct sock *sk)
1393{
1394        struct tun_file *tfile;
1395        wait_queue_head_t *wqueue;
1396
1397        if (!sock_writeable(sk))
1398                return;
1399
1400        if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1401                return;
1402
1403        wqueue = sk_sleep(sk);
1404        if (wqueue && waitqueue_active(wqueue))
1405                wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1406                                                POLLWRNORM | POLLWRBAND);
1407
1408        tfile = container_of(sk, struct tun_file, sk);
1409        kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1410}
1411
1412static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1413                       struct msghdr *m, size_t total_len)
1414{
1415        int ret;
1416        struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1417        struct tun_struct *tun = __tun_get(tfile);
1418
1419        if (!tun)
1420                return -EBADFD;
1421        ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len,
1422                           m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1423        tun_put(tun);
1424        return ret;
1425}
1426
1427static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1428                       struct msghdr *m, size_t total_len,
1429                       int flags)
1430{
1431        struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1432        struct tun_struct *tun = __tun_get(tfile);
1433        int ret;
1434
1435        if (!tun)
1436                return -EBADFD;
1437
1438        if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1439                ret = -EINVAL;
1440                goto out;
1441        }
1442        if (flags & MSG_ERRQUEUE) {
1443                ret = sock_recv_errqueue(sock->sk, m, total_len,
1444                                         SOL_PACKET, TUN_TX_TIMESTAMP);
1445                goto out;
1446        }
1447        ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len,
1448                          flags & MSG_DONTWAIT);
1449        if (ret > total_len) {
1450                m->msg_flags |= MSG_TRUNC;
1451                ret = flags & MSG_TRUNC ? ret : total_len;
1452        }
1453out:
1454        tun_put(tun);
1455        return ret;
1456}
1457
1458static int tun_release(struct socket *sock)
1459{
1460        if (sock->sk)
1461                sock_put(sock->sk);
1462        return 0;
1463}
1464
1465/* Ops structure to mimic raw sockets with tun */
1466static const struct proto_ops tun_socket_ops = {
1467        .sendmsg = tun_sendmsg,
1468        .recvmsg = tun_recvmsg,
1469        .release = tun_release,
1470};
1471
1472static struct proto tun_proto = {
1473        .name           = "tun",
1474        .owner          = THIS_MODULE,
1475        .obj_size       = sizeof(struct tun_file),
1476};
1477
1478static int tun_flags(struct tun_struct *tun)
1479{
1480        int flags = 0;
1481
1482        if (tun->flags & TUN_TUN_DEV)
1483                flags |= IFF_TUN;
1484        else
1485                flags |= IFF_TAP;
1486
1487        if (tun->flags & TUN_NO_PI)
1488                flags |= IFF_NO_PI;
1489
1490        /* This flag has no real effect.  We track the value for backwards
1491         * compatibility.
1492         */
1493        if (tun->flags & TUN_ONE_QUEUE)
1494                flags |= IFF_ONE_QUEUE;
1495
1496        if (tun->flags & TUN_VNET_HDR)
1497                flags |= IFF_VNET_HDR;
1498
1499        if (tun->flags & TUN_TAP_MQ)
1500                flags |= IFF_MULTI_QUEUE;
1501
1502        if (tun->flags & TUN_PERSIST)
1503                flags |= IFF_PERSIST;
1504
1505        return flags;
1506}
1507
1508static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1509                              char *buf)
1510{
1511        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1512        return sprintf(buf, "0x%x\n", tun_flags(tun));
1513}
1514
1515static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1516                              char *buf)
1517{
1518        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1519        return uid_valid(tun->owner)?
1520                sprintf(buf, "%u\n",
1521                        from_kuid_munged(current_user_ns(), tun->owner)):
1522                sprintf(buf, "-1\n");
1523}
1524
1525static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1526                              char *buf)
1527{
1528        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1529        return gid_valid(tun->group) ?
1530                sprintf(buf, "%u\n",
1531                        from_kgid_munged(current_user_ns(), tun->group)):
1532                sprintf(buf, "-1\n");
1533}
1534
1535static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1536static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1537static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1538
1539static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1540{
1541        struct tun_struct *tun;
1542        struct tun_file *tfile = file->private_data;
1543        struct net_device *dev;
1544        int err;
1545
1546        if (tfile->detached)
1547                return -EINVAL;
1548
1549        dev = __dev_get_by_name(net, ifr->ifr_name);
1550        if (dev) {
1551                if (ifr->ifr_flags & IFF_TUN_EXCL)
1552                        return -EBUSY;
1553                if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1554                        tun = netdev_priv(dev);
1555                else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1556                        tun = netdev_priv(dev);
1557                else
1558                        return -EINVAL;
1559
1560                if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1561                    !!(tun->flags & TUN_TAP_MQ))
1562                        return -EINVAL;
1563
1564                if (tun_not_capable(tun))
1565                        return -EPERM;
1566                err = security_tun_dev_open(tun->security);
1567                if (err < 0)
1568                        return err;
1569
1570                err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1571                if (err < 0)
1572                        return err;
1573
1574                if (tun->flags & TUN_TAP_MQ &&
1575                    (tun->numqueues + tun->numdisabled > 1)) {
1576                        /* One or more queue has already been attached, no need
1577                         * to initialize the device again.
1578                         */
1579                        return 0;
1580                }
1581        }
1582        else {
1583                char *name;
1584                unsigned long flags = 0;
1585                int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1586                             MAX_TAP_QUEUES : 1;
1587
1588                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1589                        return -EPERM;
1590                err = security_tun_dev_create();
1591                if (err < 0)
1592                        return err;
1593
1594                /* Set dev type */
1595                if (ifr->ifr_flags & IFF_TUN) {
1596                        /* TUN device */
1597                        flags |= TUN_TUN_DEV;
1598                        name = "tun%d";
1599                } else if (ifr->ifr_flags & IFF_TAP) {
1600                        /* TAP device */
1601                        flags |= TUN_TAP_DEV;
1602                        name = "tap%d";
1603                } else
1604                        return -EINVAL;
1605
1606                if (*ifr->ifr_name)
1607                        name = ifr->ifr_name;
1608
1609                dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1610                                       tun_setup, queues, queues);
1611
1612                if (!dev)
1613                        return -ENOMEM;
1614
1615                dev_net_set(dev, net);
1616                dev->rtnl_link_ops = &tun_link_ops;
1617                dev->ifindex = tfile->ifindex;
1618
1619                tun = netdev_priv(dev);
1620                tun->dev = dev;
1621                tun->flags = flags;
1622                tun->txflt.count = 0;
1623                tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1624
1625                tun->filter_attached = false;
1626                tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1627
1628                spin_lock_init(&tun->lock);
1629
1630                err = security_tun_dev_alloc_security(&tun->security);
1631                if (err < 0)
1632                        goto err_free_dev;
1633
1634                tun_net_init(dev);
1635                tun_flow_init(tun);
1636
1637                dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1638                                   TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1639                                   NETIF_F_HW_VLAN_STAG_TX;
1640                dev->features = dev->hw_features;
1641                dev->vlan_features = dev->features;
1642
1643                INIT_LIST_HEAD(&tun->disabled);
1644                err = tun_attach(tun, file, false);
1645                if (err < 0)
1646                        goto err_free_flow;
1647
1648                err = register_netdevice(tun->dev);
1649                if (err < 0)
1650                        goto err_detach;
1651
1652                if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1653                    device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1654                    device_create_file(&tun->dev->dev, &dev_attr_group))
1655                        pr_err("Failed to create tun sysfs files\n");
1656        }
1657
1658        netif_carrier_on(tun->dev);
1659
1660        tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1661
1662        if (ifr->ifr_flags & IFF_NO_PI)
1663                tun->flags |= TUN_NO_PI;
1664        else
1665                tun->flags &= ~TUN_NO_PI;
1666
1667        /* This flag has no real effect.  We track the value for backwards
1668         * compatibility.
1669         */
1670        if (ifr->ifr_flags & IFF_ONE_QUEUE)
1671                tun->flags |= TUN_ONE_QUEUE;
1672        else
1673                tun->flags &= ~TUN_ONE_QUEUE;
1674
1675        if (ifr->ifr_flags & IFF_VNET_HDR)
1676                tun->flags |= TUN_VNET_HDR;
1677        else
1678                tun->flags &= ~TUN_VNET_HDR;
1679
1680        if (ifr->ifr_flags & IFF_MULTI_QUEUE)
1681                tun->flags |= TUN_TAP_MQ;
1682        else
1683                tun->flags &= ~TUN_TAP_MQ;
1684
1685        /* Make sure persistent devices do not get stuck in
1686         * xoff state.
1687         */
1688        if (netif_running(tun->dev))
1689                netif_tx_wake_all_queues(tun->dev);
1690
1691        strcpy(ifr->ifr_name, tun->dev->name);
1692        return 0;
1693
1694err_detach:
1695        tun_detach_all(dev);
1696err_free_flow:
1697        tun_flow_uninit(tun);
1698        security_tun_dev_free_security(tun->security);
1699err_free_dev:
1700        free_netdev(dev);
1701        return err;
1702}
1703
1704static void tun_get_iff(struct net *net, struct tun_struct *tun,
1705                       struct ifreq *ifr)
1706{
1707        tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1708
1709        strcpy(ifr->ifr_name, tun->dev->name);
1710
1711        ifr->ifr_flags = tun_flags(tun);
1712
1713}
1714
1715/* This is like a cut-down ethtool ops, except done via tun fd so no
1716 * privs required. */
1717static int set_offload(struct tun_struct *tun, unsigned long arg)
1718{
1719        netdev_features_t features = 0;
1720
1721        if (arg & TUN_F_CSUM) {
1722                features |= NETIF_F_HW_CSUM;
1723                arg &= ~TUN_F_CSUM;
1724
1725                if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1726                        if (arg & TUN_F_TSO_ECN) {
1727                                features |= NETIF_F_TSO_ECN;
1728                                arg &= ~TUN_F_TSO_ECN;
1729                        }
1730                        if (arg & TUN_F_TSO4)
1731                                features |= NETIF_F_TSO;
1732                        if (arg & TUN_F_TSO6)
1733                                features |= NETIF_F_TSO6;
1734                        arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1735                }
1736
1737                if (arg & TUN_F_UFO) {
1738                        features |= NETIF_F_UFO;
1739                        arg &= ~TUN_F_UFO;
1740                }
1741        }
1742
1743        /* This gives the user a way to test for new features in future by
1744         * trying to set them. */
1745        if (arg)
1746                return -EINVAL;
1747
1748        tun->set_features = features;
1749        netdev_update_features(tun->dev);
1750
1751        return 0;
1752}
1753
1754static void tun_detach_filter(struct tun_struct *tun, int n)
1755{
1756        int i;
1757        struct tun_file *tfile;
1758
1759        for (i = 0; i < n; i++) {
1760                tfile = rtnl_dereference(tun->tfiles[i]);
1761                sk_detach_filter(tfile->socket.sk);
1762        }
1763
1764        tun->filter_attached = false;
1765}
1766
1767static int tun_attach_filter(struct tun_struct *tun)
1768{
1769        int i, ret = 0;
1770        struct tun_file *tfile;
1771
1772        for (i = 0; i < tun->numqueues; i++) {
1773                tfile = rtnl_dereference(tun->tfiles[i]);
1774                ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1775                if (ret) {
1776                        tun_detach_filter(tun, i);
1777                        return ret;
1778                }
1779        }
1780
1781        tun->filter_attached = true;
1782        return ret;
1783}
1784
1785static void tun_set_sndbuf(struct tun_struct *tun)
1786{
1787        struct tun_file *tfile;
1788        int i;
1789
1790        for (i = 0; i < tun->numqueues; i++) {
1791                tfile = rtnl_dereference(tun->tfiles[i]);
1792                tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1793        }
1794}
1795
1796static int tun_set_queue(struct file *file, struct ifreq *ifr)
1797{
1798        struct tun_file *tfile = file->private_data;
1799        struct tun_struct *tun;
1800        int ret = 0;
1801
1802        rtnl_lock();
1803
1804        if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1805                tun = tfile->detached;
1806                if (!tun) {
1807                        ret = -EINVAL;
1808                        goto unlock;
1809                }
1810                ret = security_tun_dev_attach_queue(tun->security);
1811                if (ret < 0)
1812                        goto unlock;
1813                ret = tun_attach(tun, file, false);
1814        } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1815                tun = rtnl_dereference(tfile->tun);
1816                if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached)
1817                        ret = -EINVAL;
1818                else
1819                        __tun_detach(tfile, false);
1820        } else
1821                ret = -EINVAL;
1822
1823unlock:
1824        rtnl_unlock();
1825        return ret;
1826}
1827
1828static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1829                            unsigned long arg, int ifreq_len)
1830{
1831        struct tun_file *tfile = file->private_data;
1832        struct tun_struct *tun;
1833        void __user* argp = (void __user*)arg;
1834        struct ifreq ifr;
1835        kuid_t owner;
1836        kgid_t group;
1837        int sndbuf;
1838        int vnet_hdr_sz;
1839        unsigned int ifindex;
1840        int ret;
1841
1842        if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1843                if (copy_from_user(&ifr, argp, ifreq_len))
1844                        return -EFAULT;
1845        } else {
1846                memset(&ifr, 0, sizeof(ifr));
1847        }
1848        if (cmd == TUNGETFEATURES) {
1849                /* Currently this just means: "what IFF flags are valid?".
1850                 * This is needed because we never checked for invalid flags on
1851                 * TUNSETIFF. */
1852                return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1853                                IFF_VNET_HDR | IFF_MULTI_QUEUE,
1854                                (unsigned int __user*)argp);
1855        } else if (cmd == TUNSETQUEUE)
1856                return tun_set_queue(file, &ifr);
1857
1858        ret = 0;
1859        rtnl_lock();
1860
1861        tun = __tun_get(tfile);
1862        if (cmd == TUNSETIFF && !tun) {
1863                ifr.ifr_name[IFNAMSIZ-1] = '\0';
1864
1865                ret = tun_set_iff(tfile->net, file, &ifr);
1866
1867                if (ret)
1868                        goto unlock;
1869
1870                if (copy_to_user(argp, &ifr, ifreq_len))
1871                        ret = -EFAULT;
1872                goto unlock;
1873        }
1874        if (cmd == TUNSETIFINDEX) {
1875                ret = -EPERM;
1876                if (tun)
1877                        goto unlock;
1878
1879                ret = -EFAULT;
1880                if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
1881                        goto unlock;
1882
1883                ret = 0;
1884                tfile->ifindex = ifindex;
1885                goto unlock;
1886        }
1887
1888        ret = -EBADFD;
1889        if (!tun)
1890                goto unlock;
1891
1892        tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1893
1894        ret = 0;
1895        switch (cmd) {
1896        case TUNGETIFF:
1897                tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1898
1899                if (tfile->detached)
1900                        ifr.ifr_flags |= IFF_DETACH_QUEUE;
1901                if (!tfile->socket.sk->sk_filter)
1902                        ifr.ifr_flags |= IFF_NOFILTER;
1903
1904                if (copy_to_user(argp, &ifr, ifreq_len))
1905                        ret = -EFAULT;
1906                break;
1907
1908        case TUNSETNOCSUM:
1909                /* Disable/Enable checksum */
1910
1911                /* [unimplemented] */
1912                tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1913                          arg ? "disabled" : "enabled");
1914                break;
1915
1916        case TUNSETPERSIST:
1917                /* Disable/Enable persist mode. Keep an extra reference to the
1918                 * module to prevent the module being unprobed.
1919                 */
1920                if (arg && !(tun->flags & TUN_PERSIST)) {
1921                        tun->flags |= TUN_PERSIST;
1922                        __module_get(THIS_MODULE);
1923                }
1924                if (!arg && (tun->flags & TUN_PERSIST)) {
1925                        tun->flags &= ~TUN_PERSIST;
1926                        module_put(THIS_MODULE);
1927                }
1928
1929                tun_debug(KERN_INFO, tun, "persist %s\n",
1930                          arg ? "enabled" : "disabled");
1931                break;
1932
1933        case TUNSETOWNER:
1934                /* Set owner of the device */
1935                owner = make_kuid(current_user_ns(), arg);
1936                if (!uid_valid(owner)) {
1937                        ret = -EINVAL;
1938                        break;
1939                }
1940                tun->owner = owner;
1941                tun_debug(KERN_INFO, tun, "owner set to %u\n",
1942                          from_kuid(&init_user_ns, tun->owner));
1943                break;
1944
1945        case TUNSETGROUP:
1946                /* Set group of the device */
1947                group = make_kgid(current_user_ns(), arg);
1948                if (!gid_valid(group)) {
1949                        ret = -EINVAL;
1950                        break;
1951                }
1952                tun->group = group;
1953                tun_debug(KERN_INFO, tun, "group set to %u\n",
1954                          from_kgid(&init_user_ns, tun->group));
1955                break;
1956
1957        case TUNSETLINK:
1958                /* Only allow setting the type when the interface is down */
1959                if (tun->dev->flags & IFF_UP) {
1960                        tun_debug(KERN_INFO, tun,
1961                                  "Linktype set failed because interface is up\n");
1962                        ret = -EBUSY;
1963                } else {
1964                        tun->dev->type = (int) arg;
1965                        tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1966                                  tun->dev->type);
1967                        ret = 0;
1968                }
1969                break;
1970
1971#ifdef TUN_DEBUG
1972        case TUNSETDEBUG:
1973                tun->debug = arg;
1974                break;
1975#endif
1976        case TUNSETOFFLOAD:
1977                ret = set_offload(tun, arg);
1978                break;
1979
1980        case TUNSETTXFILTER:
1981                /* Can be set only for TAPs */
1982                ret = -EINVAL;
1983                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1984                        break;
1985                ret = update_filter(&tun->txflt, (void __user *)arg);
1986                break;
1987
1988        case SIOCGIFHWADDR:
1989                /* Get hw address */
1990                memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1991                ifr.ifr_hwaddr.sa_family = tun->dev->type;
1992                if (copy_to_user(argp, &ifr, ifreq_len))
1993                        ret = -EFAULT;
1994                break;
1995
1996        case SIOCSIFHWADDR:
1997                /* Set hw address */
1998                tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1999                          ifr.ifr_hwaddr.sa_data);
2000
2001                ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2002                break;
2003
2004        case TUNGETSNDBUF:
2005                sndbuf = tfile->socket.sk->sk_sndbuf;
2006                if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2007                        ret = -EFAULT;
2008                break;
2009
2010        case TUNSETSNDBUF:
2011                if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2012                        ret = -EFAULT;
2013                        break;
2014                }
2015
2016                tun->sndbuf = sndbuf;
2017                tun_set_sndbuf(tun);
2018                break;
2019
2020        case TUNGETVNETHDRSZ:
2021                vnet_hdr_sz = tun->vnet_hdr_sz;
2022                if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2023                        ret = -EFAULT;
2024                break;
2025
2026        case TUNSETVNETHDRSZ:
2027                if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2028                        ret = -EFAULT;
2029                        break;
2030                }
2031                if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2032                        ret = -EINVAL;
2033                        break;
2034                }
2035
2036                tun->vnet_hdr_sz = vnet_hdr_sz;
2037                break;
2038
2039        case TUNATTACHFILTER:
2040                /* Can be set only for TAPs */
2041                ret = -EINVAL;
2042                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2043                        break;
2044                ret = -EFAULT;
2045                if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2046                        break;
2047
2048                ret = tun_attach_filter(tun);
2049                break;
2050
2051        case TUNDETACHFILTER:
2052                /* Can be set only for TAPs */
2053                ret = -EINVAL;
2054                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2055                        break;
2056                ret = 0;
2057                tun_detach_filter(tun, tun->numqueues);
2058                break;
2059
2060        case TUNGETFILTER:
2061                ret = -EINVAL;
2062                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2063                        break;
2064                ret = -EFAULT;
2065                if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2066                        break;
2067                ret = 0;
2068                break;
2069
2070        default:
2071                ret = -EINVAL;
2072                break;
2073        }
2074
2075unlock:
2076        rtnl_unlock();
2077        if (tun)
2078                tun_put(tun);
2079        return ret;
2080}
2081
2082static long tun_chr_ioctl(struct file *file,
2083                          unsigned int cmd, unsigned long arg)
2084{
2085        return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2086}
2087
2088#ifdef CONFIG_COMPAT
2089static long tun_chr_compat_ioctl(struct file *file,
2090                         unsigned int cmd, unsigned long arg)
2091{
2092        switch (cmd) {
2093        case TUNSETIFF:
2094        case TUNGETIFF:
2095        case TUNSETTXFILTER:
2096        case TUNGETSNDBUF:
2097        case TUNSETSNDBUF:
2098        case SIOCGIFHWADDR:
2099        case SIOCSIFHWADDR:
2100                arg = (unsigned long)compat_ptr(arg);
2101                break;
2102        default:
2103                arg = (compat_ulong_t)arg;
2104                break;
2105        }
2106
2107        /*
2108         * compat_ifreq is shorter than ifreq, so we must not access beyond
2109         * the end of that structure. All fields that are used in this
2110         * driver are compatible though, we don't need to convert the
2111         * contents.
2112         */
2113        return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2114}
2115#endif /* CONFIG_COMPAT */
2116
2117static int tun_chr_fasync(int fd, struct file *file, int on)
2118{
2119        struct tun_file *tfile = file->private_data;
2120        int ret;
2121
2122        if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2123                goto out;
2124
2125        if (on) {
2126                ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2127                if (ret)
2128                        goto out;
2129                tfile->flags |= TUN_FASYNC;
2130        } else
2131                tfile->flags &= ~TUN_FASYNC;
2132        ret = 0;
2133out:
2134        return ret;
2135}
2136
2137static int tun_chr_open(struct inode *inode, struct file * file)
2138{
2139        struct tun_file *tfile;
2140
2141        DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2142
2143        tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
2144                                            &tun_proto);
2145        if (!tfile)
2146                return -ENOMEM;
2147        rcu_assign_pointer(tfile->tun, NULL);
2148        tfile->net = get_net(current->nsproxy->net_ns);
2149        tfile->flags = 0;
2150        tfile->ifindex = 0;
2151
2152        rcu_assign_pointer(tfile->socket.wq, &tfile->wq);
2153        init_waitqueue_head(&tfile->wq.wait);
2154
2155        tfile->socket.file = file;
2156        tfile->socket.ops = &tun_socket_ops;
2157
2158        sock_init_data(&tfile->socket, &tfile->sk);
2159        sk_change_net(&tfile->sk, tfile->net);
2160
2161        tfile->sk.sk_write_space = tun_sock_write_space;
2162        tfile->sk.sk_sndbuf = INT_MAX;
2163
2164        file->private_data = tfile;
2165        set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
2166        INIT_LIST_HEAD(&tfile->next);
2167
2168        sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2169
2170        return 0;
2171}
2172
2173static int tun_chr_close(struct inode *inode, struct file *file)
2174{
2175        struct tun_file *tfile = file->private_data;
2176        struct net *net = tfile->net;
2177
2178        tun_detach(tfile, true);
2179        put_net(net);
2180
2181        return 0;
2182}
2183
2184static const struct file_operations tun_fops = {
2185        .owner  = THIS_MODULE,
2186        .llseek = no_llseek,
2187        .read  = do_sync_read,
2188        .aio_read  = tun_chr_aio_read,
2189        .write = do_sync_write,
2190        .aio_write = tun_chr_aio_write,
2191        .poll   = tun_chr_poll,
2192        .unlocked_ioctl = tun_chr_ioctl,
2193#ifdef CONFIG_COMPAT
2194        .compat_ioctl = tun_chr_compat_ioctl,
2195#endif
2196        .open   = tun_chr_open,
2197        .release = tun_chr_close,
2198        .fasync = tun_chr_fasync
2199};
2200
2201static struct miscdevice tun_miscdev = {
2202        .minor = TUN_MINOR,
2203        .name = "tun",
2204        .nodename = "net/tun",
2205        .fops = &tun_fops,
2206};
2207
2208/* ethtool interface */
2209
2210static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2211{
2212        cmd->supported          = 0;
2213        cmd->advertising        = 0;
2214        ethtool_cmd_speed_set(cmd, SPEED_10);
2215        cmd->duplex             = DUPLEX_FULL;
2216        cmd->port               = PORT_TP;
2217        cmd->phy_address        = 0;
2218        cmd->transceiver        = XCVR_INTERNAL;
2219        cmd->autoneg            = AUTONEG_DISABLE;
2220        cmd->maxtxpkt           = 0;
2221        cmd->maxrxpkt           = 0;
2222        return 0;
2223}
2224
2225static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2226{
2227        struct tun_struct *tun = netdev_priv(dev);
2228
2229        strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2230        strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2231
2232        switch (tun->flags & TUN_TYPE_MASK) {
2233        case TUN_TUN_DEV:
2234                strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2235                break;
2236        case TUN_TAP_DEV:
2237                strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2238                break;
2239        }
2240}
2241
2242static u32 tun_get_msglevel(struct net_device *dev)
2243{
2244#ifdef TUN_DEBUG
2245        struct tun_struct *tun = netdev_priv(dev);
2246        return tun->debug;
2247#else
2248        return -EOPNOTSUPP;
2249#endif
2250}
2251
2252static void tun_set_msglevel(struct net_device *dev, u32 value)
2253{
2254#ifdef TUN_DEBUG
2255        struct tun_struct *tun = netdev_priv(dev);
2256        tun->debug = value;
2257#endif
2258}
2259
2260static const struct ethtool_ops tun_ethtool_ops = {
2261        .get_settings   = tun_get_settings,
2262        .get_drvinfo    = tun_get_drvinfo,
2263        .get_msglevel   = tun_get_msglevel,
2264        .set_msglevel   = tun_set_msglevel,
2265        .get_link       = ethtool_op_get_link,
2266        .get_ts_info    = ethtool_op_get_ts_info,
2267};
2268
2269
2270static int __init tun_init(void)
2271{
2272        int ret = 0;
2273
2274        pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2275        pr_info("%s\n", DRV_COPYRIGHT);
2276
2277        ret = rtnl_link_register(&tun_link_ops);
2278        if (ret) {
2279                pr_err("Can't register link_ops\n");
2280                goto err_linkops;
2281        }
2282
2283        ret = misc_register(&tun_miscdev);
2284        if (ret) {
2285                pr_err("Can't register misc device %d\n", TUN_MINOR);
2286                goto err_misc;
2287        }
2288        return  0;
2289err_misc:
2290        rtnl_link_unregister(&tun_link_ops);
2291err_linkops:
2292        return ret;
2293}
2294
2295static void tun_cleanup(void)
2296{
2297        misc_deregister(&tun_miscdev);
2298        rtnl_link_unregister(&tun_link_ops);
2299}
2300
2301/* Get an underlying socket object from tun file.  Returns error unless file is
2302 * attached to a device.  The returned object works like a packet socket, it
2303 * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2304 * holding a reference to the file for as long as the socket is in use. */
2305struct socket *tun_get_socket(struct file *file)
2306{
2307        struct tun_file *tfile;
2308        if (file->f_op != &tun_fops)
2309                return ERR_PTR(-EINVAL);
2310        tfile = file->private_data;
2311        if (!tfile)
2312                return ERR_PTR(-EBADFD);
2313        return &tfile->socket;
2314}
2315EXPORT_SYMBOL_GPL(tun_get_socket);
2316
2317module_init(tun_init);
2318module_exit(tun_cleanup);
2319MODULE_DESCRIPTION(DRV_DESCRIPTION);
2320MODULE_AUTHOR(DRV_COPYRIGHT);
2321MODULE_LICENSE("GPL");
2322MODULE_ALIAS_MISCDEV(TUN_MINOR);
2323MODULE_ALIAS("devname:net/tun");
2324
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