drivers/net/tun.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  TUN - Universal TUN/TAP device driver.
   4  *  Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
   5  *
   6  *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
   7  */
   8
   9 /*
  10  *  Changes:
  11  *
  12  *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
  13  *    Add TUNSETLINK ioctl to set the link encapsulation
  14  *
  15  *  Mark Smith <markzzzsmith@yahoo.com.au>
  16  *    Use eth_random_addr() for tap MAC address.
  17  *
  18  *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
  19  *    Fixes in packet dropping, queue length setting and queue wakeup.
  20  *    Increased default tx queue length.
  21  *    Added ethtool API.
  22  *    Minor cleanups
  23  *
  24  *  Daniel Podlejski <underley@underley.eu.org>
  25  *    Modifications for 2.3.99-pre5 kernel.
  26  */
  27
  28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  29
  30 #define DRV_NAME        "tun"
  31 #define DRV_VERSION     "1.6"
  32 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  33 #define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
  34
  35 #include <linux/module.h>
  36 #include <linux/errno.h>
  37 #include <linux/kernel.h>
  38 #include <linux/sched/signal.h>
  39 #include <linux/major.h>
  40 #include <linux/slab.h>
  41 #include <linux/poll.h>
  42 #include <linux/fcntl.h>
  43 #include <linux/init.h>
  44 #include <linux/skbuff.h>
  45 #include <linux/netdevice.h>
  46 #include <linux/etherdevice.h>
  47 #include <linux/miscdevice.h>
  48 #include <linux/ethtool.h>
  49 #include <linux/rtnetlink.h>
  50 #include <linux/compat.h>
  51 #include <linux/if.h>
  52 #include <linux/if_arp.h>
  53 #include <linux/if_ether.h>
  54 #include <linux/if_tun.h>
  55 #include <linux/if_vlan.h>
  56 #include <linux/crc32.h>
  57 #include <linux/nsproxy.h>
  58 #include <linux/virtio_net.h>
  59 #include <linux/rcupdate.h>
  60 #include <net/net_namespace.h>
  61 #include <net/netns/generic.h>
  62 #include <net/rtnetlink.h>
  63 #include <net/sock.h>
  64 #include <net/xdp.h>
  65 #include <net/ip_tunnels.h>
  66 #include <linux/seq_file.h>
  67 #include <linux/uio.h>
  68 #include <linux/skb_array.h>
  69 #include <linux/bpf.h>
  70 #include <linux/bpf_trace.h>
  71 #include <linux/mutex.h>
  72
  73 #include <linux/uaccess.h>
  74 #include <linux/proc_fs.h>
  75
  76 static void tun_default_link_ksettings(struct net_device *dev,
  77                                        struct ethtool_link_ksettings *cmd);
  78
  79 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
  80
  81 /* TUN device flags */
  82
  83 /* IFF_ATTACH_QUEUE is never stored in device flags,
  84  * overload it to mean fasync when stored there.
  85  */
  86 #define TUN_FASYNC      IFF_ATTACH_QUEUE
  87 /* High bits in flags field are unused. */
  88 #define TUN_VNET_LE     0x80000000
  89 #define TUN_VNET_BE     0x40000000
  90
  91 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
  92                       IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
  93
  94 #define GOODCOPY_LEN 128
  95
  96 #define FLT_EXACT_COUNT 8
  97 struct tap_filter {
  98         unsigned int    count;    /* Number of addrs. Zero means disabled */
  99         u32             mask[2];  /* Mask of the hashed addrs */
 100         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 101 };
 102
 103 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
 104  * to max number of VCPUs in guest. */
 105 #define MAX_TAP_QUEUES 256
 106 #define MAX_TAP_FLOWS  4096
 107
 108 #define TUN_FLOW_EXPIRE (3 * HZ)
 109
 110 /* A tun_file connects an open character device to a tuntap netdevice. It
 111  * also contains all socket related structures (except sock_fprog and tap_filter)
 112  * to serve as one transmit queue for tuntap device. The sock_fprog and
 113  * tap_filter were kept in tun_struct since they were used for filtering for the
 114  * netdevice not for a specific queue (at least I didn't see the requirement for
 115  * this).
 116  *
 117  * RCU usage:
 118  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
 119  * other can only be read while rcu_read_lock or rtnl_lock is held.
 120  */
 121 struct tun_file {
 122         struct sock sk;
 123         struct socket socket;
 124         struct tun_struct __rcu *tun;
 125         struct fasync_struct *fasync;
 126         /* only used for fasnyc */
 127         unsigned int flags;
 128         union {
 129                 u16 queue_index;
 130                 unsigned int ifindex;
 131         };
 132         struct napi_struct napi;
 133         bool napi_enabled;
 134         bool napi_frags_enabled;
 135         struct mutex napi_mutex;        /* Protects access to the above napi */
 136         struct list_head next;
 137         struct tun_struct *detached;
 138         struct ptr_ring tx_ring;
 139         struct xdp_rxq_info xdp_rxq;
 140 };
 141
 142 struct tun_page {
 143         struct page *page;
 144         int count;
 145 };
 146
 147 struct tun_flow_entry {
 148         struct hlist_node hash_link;
 149         struct rcu_head rcu;
 150         struct tun_struct *tun;
 151
 152         u32 rxhash;
 153         u32 rps_rxhash;
 154         int queue_index;
 155         unsigned long updated ____cacheline_aligned_in_smp;
 156 };
 157
 158 #define TUN_NUM_FLOW_ENTRIES 1024
 159 #define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
 160
 161 struct tun_prog {
 162         struct rcu_head rcu;
 163         struct bpf_prog *prog;
 164 };
 165
 166 /* Since the socket were moved to tun_file, to preserve the behavior of persist
 167  * device, socket filter, sndbuf and vnet header size were restore when the
 168  * file were attached to a persist device.
 169  */
 170 struct tun_struct {
 171         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
 172         unsigned int            numqueues;
 173         unsigned int            flags;
 174         kuid_t                  owner;
 175         kgid_t                  group;
 176
 177         struct net_device       *dev;
 178         netdev_features_t       set_features;
 179 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 180                           NETIF_F_TSO6)
 181
 182         int                     align;
 183         int                     vnet_hdr_sz;
 184         int                     sndbuf;
 185         struct tap_filter       txflt;
 186         struct sock_fprog       fprog;
 187         /* protected by rtnl lock */
 188         bool                    filter_attached;
 189         u32                     msg_enable;
 190         spinlock_t lock;
 191         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 192         struct timer_list flow_gc_timer;
 193         unsigned long ageing_time;
 194         unsigned int numdisabled;
 195         struct list_head disabled;
 196         void *security;
 197         u32 flow_count;
 198         u32 rx_batched;
 199         atomic_long_t rx_frame_errors;
 200         struct bpf_prog __rcu *xdp_prog;
 201         struct tun_prog __rcu *steering_prog;
 202         struct tun_prog __rcu *filter_prog;
 203         struct ethtool_link_ksettings link_ksettings;
 204 };
 205
 206 struct veth {
 207         __be16 h_vlan_proto;
 208         __be16 h_vlan_TCI;
 209 };
 210
 211 static int tun_napi_receive(struct napi_struct *napi, int budget)
 212 {
 213         struct tun_file *tfile = container_of(napi, struct tun_file, napi);
 214         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
 215         struct sk_buff_head process_queue;
 216         struct sk_buff *skb;
 217         int received = 0;
 218
 219         __skb_queue_head_init(&process_queue);
 220
 221         spin_lock(&queue->lock);
 222         skb_queue_splice_tail_init(queue, &process_queue);
 223         spin_unlock(&queue->lock);
 224
 225         while (received < budget && (skb = __skb_dequeue(&process_queue))) {
 226                 napi_gro_receive(napi, skb);
 227                 ++received;
 228         }
 229
 230         if (!skb_queue_empty(&process_queue)) {
 231                 spin_lock(&queue->lock);
 232                 skb_queue_splice(&process_queue, queue);
 233                 spin_unlock(&queue->lock);
 234         }
 235
 236         return received;
 237 }
 238
 239 static int tun_napi_poll(struct napi_struct *napi, int budget)
 240 {
 241         unsigned int received;
 242
 243         received = tun_napi_receive(napi, budget);
 244
 245         if (received < budget)
 246                 napi_complete_done(napi, received);
 247
 248         return received;
 249 }
 250
 251 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
 252                           bool napi_en, bool napi_frags)
 253 {
 254         tfile->napi_enabled = napi_en;
 255         tfile->napi_frags_enabled = napi_en && napi_frags;
 256         if (napi_en) {
 257                 netif_tx_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
 258                                   NAPI_POLL_WEIGHT);
 259                 napi_enable(&tfile->napi);
 260         }
 261 }
 262
 263 static void tun_napi_disable(struct tun_file *tfile)
 264 {
 265         if (tfile->napi_enabled)
 266                 napi_disable(&tfile->napi);
 267 }
 268
 269 static void tun_napi_del(struct tun_file *tfile)
 270 {
 271         if (tfile->napi_enabled)
 272                 netif_napi_del(&tfile->napi);
 273 }
 274
 275 static bool tun_napi_frags_enabled(const struct tun_file *tfile)
 276 {
 277         return tfile->napi_frags_enabled;
 278 }
 279
 280 #ifdef CONFIG_TUN_VNET_CROSS_LE
 281 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 282 {
 283         return tun->flags & TUN_VNET_BE ? false :
 284                 virtio_legacy_is_little_endian();
 285 }
 286
 287 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 288 {
 289         int be = !!(tun->flags & TUN_VNET_BE);
 290
 291         if (put_user(be, argp))
 292                 return -EFAULT;
 293
 294         return 0;
 295 }
 296
 297 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 298 {
 299         int be;
 300
 301         if (get_user(be, argp))
 302                 return -EFAULT;
 303
 304         if (be)
 305                 tun->flags |= TUN_VNET_BE;
 306         else
 307                 tun->flags &= ~TUN_VNET_BE;
 308
 309         return 0;
 310 }
 311 #else
 312 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 313 {
 314         return virtio_legacy_is_little_endian();
 315 }
 316
 317 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 318 {
 319         return -EINVAL;
 320 }
 321
 322 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 323 {
 324         return -EINVAL;
 325 }
 326 #endif /* CONFIG_TUN_VNET_CROSS_LE */
 327
 328 static inline bool tun_is_little_endian(struct tun_struct *tun)
 329 {
 330         return tun->flags & TUN_VNET_LE ||
 331                 tun_legacy_is_little_endian(tun);
 332 }
 333
 334 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
 335 {
 336         return __virtio16_to_cpu(tun_is_little_endian(tun), val);
 337 }
 338
 339 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
 340 {
 341         return __cpu_to_virtio16(tun_is_little_endian(tun), val);
 342 }
 343
 344 static inline u32 tun_hashfn(u32 rxhash)
 345 {
 346         return rxhash & TUN_MASK_FLOW_ENTRIES;
 347 }
 348
 349 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 350 {
 351         struct tun_flow_entry *e;
 352
 353         hlist_for_each_entry_rcu(e, head, hash_link) {
 354                 if (e->rxhash == rxhash)
 355                         return e;
 356         }
 357         return NULL;
 358 }
 359
 360 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 361                                               struct hlist_head *head,
 362                                               u32 rxhash, u16 queue_index)
 363 {
 364         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 365
 366         if (e) {
 367                 netif_info(tun, tx_queued, tun->dev,
 368                            "create flow: hash %u index %u\n",
 369                            rxhash, queue_index);
 370                 e->updated = jiffies;
 371                 e->rxhash = rxhash;
 372                 e->rps_rxhash = 0;
 373                 e->queue_index = queue_index;
 374                 e->tun = tun;
 375                 hlist_add_head_rcu(&e->hash_link, head);
 376                 ++tun->flow_count;
 377         }
 378         return e;
 379 }
 380
 381 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 382 {
 383         netif_info(tun, tx_queued, tun->dev, "delete flow: hash %u index %u\n",
 384                    e->rxhash, e->queue_index);
 385         hlist_del_rcu(&e->hash_link);
 386         kfree_rcu(e, rcu);
 387         --tun->flow_count;
 388 }
 389
 390 static void tun_flow_flush(struct tun_struct *tun)
 391 {
 392         int i;
 393
 394         spin_lock_bh(&tun->lock);
 395         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 396                 struct tun_flow_entry *e;
 397                 struct hlist_node *n;
 398
 399                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 400                         tun_flow_delete(tun, e);
 401         }
 402         spin_unlock_bh(&tun->lock);
 403 }
 404
 405 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 406 {
 407         int i;
 408
 409         spin_lock_bh(&tun->lock);
 410         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 411                 struct tun_flow_entry *e;
 412                 struct hlist_node *n;
 413
 414                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 415                         if (e->queue_index == queue_index)
 416                                 tun_flow_delete(tun, e);
 417                 }
 418         }
 419         spin_unlock_bh(&tun->lock);
 420 }
 421
 422 static void tun_flow_cleanup(struct timer_list *t)
 423 {
 424         struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
 425         unsigned long delay = tun->ageing_time;
 426         unsigned long next_timer = jiffies + delay;
 427         unsigned long count = 0;
 428         int i;
 429
 430         spin_lock(&tun->lock);
 431         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 432                 struct tun_flow_entry *e;
 433                 struct hlist_node *n;
 434
 435                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 436                         unsigned long this_timer;
 437
 438                         this_timer = e->updated + delay;
 439                         if (time_before_eq(this_timer, jiffies)) {
 440                                 tun_flow_delete(tun, e);
 441                                 continue;
 442                         }
 443                         count++;
 444                         if (time_before(this_timer, next_timer))
 445                                 next_timer = this_timer;
 446                 }
 447         }
 448
 449         if (count)
 450                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 451         spin_unlock(&tun->lock);
 452 }
 453
 454 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 455                             struct tun_file *tfile)
 456 {
 457         struct hlist_head *head;
 458         struct tun_flow_entry *e;
 459         unsigned long delay = tun->ageing_time;
 460         u16 queue_index = tfile->queue_index;
 461
 462         head = &tun->flows[tun_hashfn(rxhash)];
 463
 464         rcu_read_lock();
 465
 466         e = tun_flow_find(head, rxhash);
 467         if (likely(e)) {
 468                 /* TODO: keep queueing to old queue until it's empty? */
 469                 if (READ_ONCE(e->queue_index) != queue_index)
 470                         WRITE_ONCE(e->queue_index, queue_index);
 471                 if (e->updated != jiffies)
 472                         e->updated = jiffies;
 473                 sock_rps_record_flow_hash(e->rps_rxhash);
 474         } else {
 475                 spin_lock_bh(&tun->lock);
 476                 if (!tun_flow_find(head, rxhash) &&
 477                     tun->flow_count < MAX_TAP_FLOWS)
 478                         tun_flow_create(tun, head, rxhash, queue_index);
 479
 480                 if (!timer_pending(&tun->flow_gc_timer))
 481                         mod_timer(&tun->flow_gc_timer,
 482                                   round_jiffies_up(jiffies + delay));
 483                 spin_unlock_bh(&tun->lock);
 484         }
 485
 486         rcu_read_unlock();
 487 }
 488
 489 /* Save the hash received in the stack receive path and update the
 490  * flow_hash table accordingly.
 491  */
 492 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
 493 {
 494         if (unlikely(e->rps_rxhash != hash))
 495                 e->rps_rxhash = hash;
 496 }
 497
 498 /* We try to identify a flow through its rxhash. The reason that
 499  * we do not check rxq no. is because some cards(e.g 82599), chooses
 500  * the rxq based on the txq where the last packet of the flow comes. As
 501  * the userspace application move between processors, we may get a
 502  * different rxq no. here.
 503  */
 504 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 505 {
 506         struct tun_flow_entry *e;
 507         u32 txq = 0;
 508         u32 numqueues = 0;
 509
 510         numqueues = READ_ONCE(tun->numqueues);
 511
 512         txq = __skb_get_hash_symmetric(skb);
 513         e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 514         if (e) {
 515                 tun_flow_save_rps_rxhash(e, txq);
 516                 txq = e->queue_index;
 517         } else {
 518                 /* use multiply and shift instead of expensive divide */
 519                 txq = ((u64)txq * numqueues) >> 32;
 520         }
 521
 522         return txq;
 523 }
 524
 525 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 526 {
 527         struct tun_prog *prog;
 528         u32 numqueues;
 529         u16 ret = 0;
 530
 531         numqueues = READ_ONCE(tun->numqueues);
 532         if (!numqueues)
 533                 return 0;
 534
 535         prog = rcu_dereference(tun->steering_prog);
 536         if (prog)
 537                 ret = bpf_prog_run_clear_cb(prog->prog, skb);
 538
 539         return ret % numqueues;
 540 }
 541
 542 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
 543                             struct net_device *sb_dev)
 544 {
 545         struct tun_struct *tun = netdev_priv(dev);
 546         u16 ret;
 547
 548         rcu_read_lock();
 549         if (rcu_dereference(tun->steering_prog))
 550                 ret = tun_ebpf_select_queue(tun, skb);
 551         else
 552                 ret = tun_automq_select_queue(tun, skb);
 553         rcu_read_unlock();
 554
 555         return ret;
 556 }
 557
 558 static inline bool tun_not_capable(struct tun_struct *tun)
 559 {
 560         const struct cred *cred = current_cred();
 561         struct net *net = dev_net(tun->dev);
 562
 563         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 564                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 565                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 566 }
 567
 568 static void tun_set_real_num_queues(struct tun_struct *tun)
 569 {
 570         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 571         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 572 }
 573
 574 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 575 {
 576         tfile->detached = tun;
 577         list_add_tail(&tfile->next, &tun->disabled);
 578         ++tun->numdisabled;
 579 }
 580
 581 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 582 {
 583         struct tun_struct *tun = tfile->detached;
 584
 585         tfile->detached = NULL;
 586         list_del_init(&tfile->next);
 587         --tun->numdisabled;
 588         return tun;
 589 }
 590
 591 void tun_ptr_free(void *ptr)
 592 {
 593         if (!ptr)
 594                 return;
 595         if (tun_is_xdp_frame(ptr)) {
 596                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
 597
 598                 xdp_return_frame(xdpf);
 599         } else {
 600                 __skb_array_destroy_skb(ptr);
 601         }
 602 }
 603 EXPORT_SYMBOL_GPL(tun_ptr_free);
 604
 605 static void tun_queue_purge(struct tun_file *tfile)
 606 {
 607         void *ptr;
 608
 609         while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
 610                 tun_ptr_free(ptr);
 611
 612         skb_queue_purge(&tfile->sk.sk_write_queue);
 613         skb_queue_purge(&tfile->sk.sk_error_queue);
 614 }
 615
 616 static void __tun_detach(struct tun_file *tfile, bool clean)
 617 {
 618         struct tun_file *ntfile;
 619         struct tun_struct *tun;
 620
 621         tun = rtnl_dereference(tfile->tun);
 622
 623         if (tun && clean) {
 624                 tun_napi_disable(tfile);
 625                 tun_napi_del(tfile);
 626         }
 627
 628         if (tun && !tfile->detached) {
 629                 u16 index = tfile->queue_index;
 630                 BUG_ON(index >= tun->numqueues);
 631
 632                 rcu_assign_pointer(tun->tfiles[index],
 633                                    tun->tfiles[tun->numqueues - 1]);
 634                 ntfile = rtnl_dereference(tun->tfiles[index]);
 635                 ntfile->queue_index = index;
 636                 rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
 637                                    NULL);
 638
 639                 --tun->numqueues;
 640                 if (clean) {
 641                         RCU_INIT_POINTER(tfile->tun, NULL);
 642                         sock_put(&tfile->sk);
 643                 } else
 644                         tun_disable_queue(tun, tfile);
 645
 646                 synchronize_net();
 647                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 648                 /* Drop read queue */
 649                 tun_queue_purge(tfile);
 650                 tun_set_real_num_queues(tun);
 651         } else if (tfile->detached && clean) {
 652                 tun = tun_enable_queue(tfile);
 653                 sock_put(&tfile->sk);
 654         }
 655
 656         if (clean) {
 657                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 658                         netif_carrier_off(tun->dev);
 659
 660                         if (!(tun->flags & IFF_PERSIST) &&
 661                             tun->dev->reg_state == NETREG_REGISTERED)
 662                                 unregister_netdevice(tun->dev);
 663                 }
 664                 if (tun)
 665                         xdp_rxq_info_unreg(&tfile->xdp_rxq);
 666                 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
 667                 sock_put(&tfile->sk);
 668         }
 669 }
 670
 671 static void tun_detach(struct tun_file *tfile, bool clean)
 672 {
 673         struct tun_struct *tun;
 674         struct net_device *dev;
 675
 676         rtnl_lock();
 677         tun = rtnl_dereference(tfile->tun);
 678         dev = tun ? tun->dev : NULL;
 679         __tun_detach(tfile, clean);
 680         if (dev)
 681                 netdev_state_change(dev);
 682         rtnl_unlock();
 683 }
 684
 685 static void tun_detach_all(struct net_device *dev)
 686 {
 687         struct tun_struct *tun = netdev_priv(dev);
 688         struct tun_file *tfile, *tmp;
 689         int i, n = tun->numqueues;
 690
 691         for (i = 0; i < n; i++) {
 692                 tfile = rtnl_dereference(tun->tfiles[i]);
 693                 BUG_ON(!tfile);
 694                 tun_napi_disable(tfile);
 695                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 696                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 697                 RCU_INIT_POINTER(tfile->tun, NULL);
 698                 --tun->numqueues;
 699         }
 700         list_for_each_entry(tfile, &tun->disabled, next) {
 701                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 702                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 703                 RCU_INIT_POINTER(tfile->tun, NULL);
 704         }
 705         BUG_ON(tun->numqueues != 0);
 706
 707         synchronize_net();
 708         for (i = 0; i < n; i++) {
 709                 tfile = rtnl_dereference(tun->tfiles[i]);
 710                 tun_napi_del(tfile);
 711                 /* Drop read queue */
 712                 tun_queue_purge(tfile);
 713                 xdp_rxq_info_unreg(&tfile->xdp_rxq);
 714                 sock_put(&tfile->sk);
 715         }
 716         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 717                 tun_enable_queue(tfile);
 718                 tun_queue_purge(tfile);
 719                 xdp_rxq_info_unreg(&tfile->xdp_rxq);
 720                 sock_put(&tfile->sk);
 721         }
 722         BUG_ON(tun->numdisabled != 0);
 723
 724         if (tun->flags & IFF_PERSIST)
 725                 module_put(THIS_MODULE);
 726 }
 727
 728 static int tun_attach(struct tun_struct *tun, struct file *file,
 729                       bool skip_filter, bool napi, bool napi_frags,
 730                       bool publish_tun)
 731 {
 732         struct tun_file *tfile = file->private_data;
 733         struct net_device *dev = tun->dev;
 734         int err;
 735
 736         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 737         if (err < 0)
 738                 goto out;
 739
 740         err = -EINVAL;
 741         if (rtnl_dereference(tfile->tun) && !tfile->detached)
 742                 goto out;
 743
 744         err = -EBUSY;
 745         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
 746                 goto out;
 747
 748         err = -E2BIG;
 749         if (!tfile->detached &&
 750             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 751                 goto out;
 752
 753         err = 0;
 754
 755         /* Re-attach the filter to persist device */
 756         if (!skip_filter && (tun->filter_attached == true)) {
 757                 lock_sock(tfile->socket.sk);
 758                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 759                 release_sock(tfile->socket.sk);
 760                 if (!err)
 761                         goto out;
 762         }
 763
 764         if (!tfile->detached &&
 765             ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
 766                             GFP_KERNEL, tun_ptr_free)) {
 767                 err = -ENOMEM;
 768                 goto out;
 769         }
 770
 771         tfile->queue_index = tun->numqueues;
 772         tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
 773
 774         if (tfile->detached) {
 775                 /* Re-attach detached tfile, updating XDP queue_index */
 776                 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
 777
 778                 if (tfile->xdp_rxq.queue_index    != tfile->queue_index)
 779                         tfile->xdp_rxq.queue_index = tfile->queue_index;
 780         } else {
 781                 /* Setup XDP RX-queue info, for new tfile getting attached */
 782                 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
 783                                        tun->dev, tfile->queue_index, 0);
 784                 if (err < 0)
 785                         goto out;
 786                 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
 787                                                  MEM_TYPE_PAGE_SHARED, NULL);
 788                 if (err < 0) {
 789                         xdp_rxq_info_unreg(&tfile->xdp_rxq);
 790                         goto out;
 791                 }
 792                 err = 0;
 793         }
 794
 795         if (tfile->detached) {
 796                 tun_enable_queue(tfile);
 797         } else {
 798                 sock_hold(&tfile->sk);
 799                 tun_napi_init(tun, tfile, napi, napi_frags);
 800         }
 801
 802         if (rtnl_dereference(tun->xdp_prog))
 803                 sock_set_flag(&tfile->sk, SOCK_XDP);
 804
 805         /* device is allowed to go away first, so no need to hold extra
 806          * refcnt.
 807          */
 808
 809         /* Publish tfile->tun and tun->tfiles only after we've fully
 810          * initialized tfile; otherwise we risk using half-initialized
 811          * object.
 812          */
 813         if (publish_tun)
 814                 rcu_assign_pointer(tfile->tun, tun);
 815         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 816         tun->numqueues++;
 817         tun_set_real_num_queues(tun);
 818 out:
 819         return err;
 820 }
 821
 822 static struct tun_struct *tun_get(struct tun_file *tfile)
 823 {
 824         struct tun_struct *tun;
 825
 826         rcu_read_lock();
 827         tun = rcu_dereference(tfile->tun);
 828         if (tun)
 829                 dev_hold(tun->dev);
 830         rcu_read_unlock();
 831
 832         return tun;
 833 }
 834
 835 static void tun_put(struct tun_struct *tun)
 836 {
 837         dev_put(tun->dev);
 838 }
 839
 840 /* TAP filtering */
 841 static void addr_hash_set(u32 *mask, const u8 *addr)
 842 {
 843         int n = ether_crc(ETH_ALEN, addr) >> 26;
 844         mask[n >> 5] |= (1 << (n & 31));
 845 }
 846
 847 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 848 {
 849         int n = ether_crc(ETH_ALEN, addr) >> 26;
 850         return mask[n >> 5] & (1 << (n & 31));
 851 }
 852
 853 static int update_filter(struct tap_filter *filter, void __user *arg)
 854 {
 855         struct { u8 u[ETH_ALEN]; } *addr;
 856         struct tun_filter uf;
 857         int err, alen, n, nexact;
 858
 859         if (copy_from_user(&uf, arg, sizeof(uf)))
 860                 return -EFAULT;
 861
 862         if (!uf.count) {
 863                 /* Disabled */
 864                 filter->count = 0;
 865                 return 0;
 866         }
 867
 868         alen = ETH_ALEN * uf.count;
 869         addr = memdup_user(arg + sizeof(uf), alen);
 870         if (IS_ERR(addr))
 871                 return PTR_ERR(addr);
 872
 873         /* The filter is updated without holding any locks. Which is
 874          * perfectly safe. We disable it first and in the worst
 875          * case we'll accept a few undesired packets. */
 876         filter->count = 0;
 877         wmb();
 878
 879         /* Use first set of addresses as an exact filter */
 880         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 881                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 882
 883         nexact = n;
 884
 885         /* Remaining multicast addresses are hashed,
 886          * unicast will leave the filter disabled. */
 887         memset(filter->mask, 0, sizeof(filter->mask));
 888         for (; n < uf.count; n++) {
 889                 if (!is_multicast_ether_addr(addr[n].u)) {
 890                         err = 0; /* no filter */
 891                         goto free_addr;
 892                 }
 893                 addr_hash_set(filter->mask, addr[n].u);
 894         }
 895
 896         /* For ALLMULTI just set the mask to all ones.
 897          * This overrides the mask populated above. */
 898         if ((uf.flags & TUN_FLT_ALLMULTI))
 899                 memset(filter->mask, ~0, sizeof(filter->mask));
 900
 901         /* Now enable the filter */
 902         wmb();
 903         filter->count = nexact;
 904
 905         /* Return the number of exact filters */
 906         err = nexact;
 907 free_addr:
 908         kfree(addr);
 909         return err;
 910 }
 911
 912 /* Returns: 0 - drop, !=0 - accept */
 913 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 914 {
 915         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 916          * at this point. */
 917         struct ethhdr *eh = (struct ethhdr *) skb->data;
 918         int i;
 919
 920         /* Exact match */
 921         for (i = 0; i < filter->count; i++)
 922                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 923                         return 1;
 924
 925         /* Inexact match (multicast only) */
 926         if (is_multicast_ether_addr(eh->h_dest))
 927                 return addr_hash_test(filter->mask, eh->h_dest);
 928
 929         return 0;
 930 }
 931
 932 /*
 933  * Checks whether the packet is accepted or not.
 934  * Returns: 0 - drop, !=0 - accept
 935  */
 936 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 937 {
 938         if (!filter->count)
 939                 return 1;
 940
 941         return run_filter(filter, skb);
 942 }
 943
 944 /* Network device part of the driver */
 945
 946 static const struct ethtool_ops tun_ethtool_ops;
 947
 948 /* Net device detach from fd. */
 949 static void tun_net_uninit(struct net_device *dev)
 950 {
 951         tun_detach_all(dev);
 952 }
 953
 954 /* Net device open. */
 955 static int tun_net_open(struct net_device *dev)
 956 {
 957         netif_tx_start_all_queues(dev);
 958
 959         return 0;
 960 }
 961
 962 /* Net device close. */
 963 static int tun_net_close(struct net_device *dev)
 964 {
 965         netif_tx_stop_all_queues(dev);
 966         return 0;
 967 }
 968
 969 /* Net device start xmit */
 970 static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
 971 {
 972 #ifdef CONFIG_RPS
 973         if (tun->numqueues == 1 && static_branch_unlikely(&rps_needed)) {
 974                 /* Select queue was not called for the skbuff, so we extract the
 975                  * RPS hash and save it into the flow_table here.
 976                  */
 977                 struct tun_flow_entry *e;
 978                 __u32 rxhash;
 979
 980                 rxhash = __skb_get_hash_symmetric(skb);
 981                 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
 982                 if (e)
 983                         tun_flow_save_rps_rxhash(e, rxhash);
 984         }
 985 #endif
 986 }
 987
 988 static unsigned int run_ebpf_filter(struct tun_struct *tun,
 989                                     struct sk_buff *skb,
 990                                     int len)
 991 {
 992         struct tun_prog *prog = rcu_dereference(tun->filter_prog);
 993
 994         if (prog)
 995                 len = bpf_prog_run_clear_cb(prog->prog, skb);
 996
 997         return len;
 998 }
 999
1000 /* Net device start xmit */
1001 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1002 {
1003         struct tun_struct *tun = netdev_priv(dev);
1004         int txq = skb->queue_mapping;
1005         struct tun_file *tfile;
1006         int len = skb->len;
1007
1008         rcu_read_lock();
1009         tfile = rcu_dereference(tun->tfiles[txq]);
1010
1011         /* Drop packet if interface is not attached */
1012         if (!tfile)
1013                 goto drop;
1014
1015         if (!rcu_dereference(tun->steering_prog))
1016                 tun_automq_xmit(tun, skb);
1017
1018         netif_info(tun, tx_queued, tun->dev, "%s %d\n", __func__, skb->len);
1019
1020         /* Drop if the filter does not like it.
1021          * This is a noop if the filter is disabled.
1022          * Filter can be enabled only for the TAP devices. */
1023         if (!check_filter(&tun->txflt, skb))
1024                 goto drop;
1025
1026         if (tfile->socket.sk->sk_filter &&
1027             sk_filter(tfile->socket.sk, skb))
1028                 goto drop;
1029
1030         len = run_ebpf_filter(tun, skb, len);
1031         if (len == 0 || pskb_trim(skb, len))
1032                 goto drop;
1033
1034         if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1035                 goto drop;
1036
1037         skb_tx_timestamp(skb);
1038
1039         /* Orphan the skb - required as we might hang on to it
1040          * for indefinite time.
1041          */
1042         skb_orphan(skb);
1043
1044         nf_reset_ct(skb);
1045
1046         if (ptr_ring_produce(&tfile->tx_ring, skb))
1047                 goto drop;
1048
1049         /* Notify and wake up reader process */
1050         if (tfile->flags & TUN_FASYNC)
1051                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1052         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1053
1054         rcu_read_unlock();
1055         return NETDEV_TX_OK;
1056
1057 drop:
1058         atomic_long_inc(&dev->tx_dropped);
1059         skb_tx_error(skb);
1060         kfree_skb(skb);
1061         rcu_read_unlock();
1062         return NET_XMIT_DROP;
1063 }
1064
1065 static void tun_net_mclist(struct net_device *dev)
1066 {
1067         /*
1068          * This callback is supposed to deal with mc filter in
1069          * _rx_ path and has nothing to do with the _tx_ path.
1070          * In rx path we always accept everything userspace gives us.
1071          */
1072 }
1073
1074 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1075         netdev_features_t features)
1076 {
1077         struct tun_struct *tun = netdev_priv(dev);
1078
1079         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1080 }
1081
1082 static void tun_set_headroom(struct net_device *dev, int new_hr)
1083 {
1084         struct tun_struct *tun = netdev_priv(dev);
1085
1086         if (new_hr < NET_SKB_PAD)
1087                 new_hr = NET_SKB_PAD;
1088
1089         tun->align = new_hr;
1090 }
1091
1092 static void
1093 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1094 {
1095         struct tun_struct *tun = netdev_priv(dev);
1096
1097         dev_get_tstats64(dev, stats);
1098
1099         stats->rx_frame_errors +=
1100                 (unsigned long)atomic_long_read(&tun->rx_frame_errors);
1101 }
1102
1103 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1104                        struct netlink_ext_ack *extack)
1105 {
1106         struct tun_struct *tun = netdev_priv(dev);
1107         struct tun_file *tfile;
1108         struct bpf_prog *old_prog;
1109         int i;
1110
1111         old_prog = rtnl_dereference(tun->xdp_prog);
1112         rcu_assign_pointer(tun->xdp_prog, prog);
1113         if (old_prog)
1114                 bpf_prog_put(old_prog);
1115
1116         for (i = 0; i < tun->numqueues; i++) {
1117                 tfile = rtnl_dereference(tun->tfiles[i]);
1118                 if (prog)
1119                         sock_set_flag(&tfile->sk, SOCK_XDP);
1120                 else
1121                         sock_reset_flag(&tfile->sk, SOCK_XDP);
1122         }
1123         list_for_each_entry(tfile, &tun->disabled, next) {
1124                 if (prog)
1125                         sock_set_flag(&tfile->sk, SOCK_XDP);
1126                 else
1127                         sock_reset_flag(&tfile->sk, SOCK_XDP);
1128         }
1129
1130         return 0;
1131 }
1132
1133 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1134 {
1135         switch (xdp->command) {
1136         case XDP_SETUP_PROG:
1137                 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1138         default:
1139                 return -EINVAL;
1140         }
1141 }
1142
1143 static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1144 {
1145         if (new_carrier) {
1146                 struct tun_struct *tun = netdev_priv(dev);
1147
1148                 if (!tun->numqueues)
1149                         return -EPERM;
1150
1151                 netif_carrier_on(dev);
1152         } else {
1153                 netif_carrier_off(dev);
1154         }
1155         return 0;
1156 }
1157
1158 static const struct net_device_ops tun_netdev_ops = {
1159         .ndo_uninit             = tun_net_uninit,
1160         .ndo_open               = tun_net_open,
1161         .ndo_stop               = tun_net_close,
1162         .ndo_start_xmit         = tun_net_xmit,
1163         .ndo_fix_features       = tun_net_fix_features,
1164         .ndo_select_queue       = tun_select_queue,
1165         .ndo_set_rx_headroom    = tun_set_headroom,
1166         .ndo_get_stats64        = tun_net_get_stats64,
1167         .ndo_change_carrier     = tun_net_change_carrier,
1168 };
1169
1170 static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1171 {
1172         /* Notify and wake up reader process */
1173         if (tfile->flags & TUN_FASYNC)
1174                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1175         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1176 }
1177
1178 static int tun_xdp_xmit(struct net_device *dev, int n,
1179                         struct xdp_frame **frames, u32 flags)
1180 {
1181         struct tun_struct *tun = netdev_priv(dev);
1182         struct tun_file *tfile;
1183         u32 numqueues;
1184         int drops = 0;
1185         int cnt = n;
1186         int i;
1187
1188         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1189                 return -EINVAL;
1190
1191         rcu_read_lock();
1192
1193 resample:
1194         numqueues = READ_ONCE(tun->numqueues);
1195         if (!numqueues) {
1196                 rcu_read_unlock();
1197                 return -ENXIO; /* Caller will free/return all frames */
1198         }
1199
1200         tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1201                                             numqueues]);
1202         if (unlikely(!tfile))
1203                 goto resample;
1204
1205         spin_lock(&tfile->tx_ring.producer_lock);
1206         for (i = 0; i < n; i++) {
1207                 struct xdp_frame *xdp = frames[i];
1208                 /* Encode the XDP flag into lowest bit for consumer to differ
1209                  * XDP buffer from sk_buff.
1210                  */
1211                 void *frame = tun_xdp_to_ptr(xdp);
1212
1213                 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1214                         atomic_long_inc(&dev->tx_dropped);
1215                         xdp_return_frame_rx_napi(xdp);
1216                         drops++;
1217                 }
1218         }
1219         spin_unlock(&tfile->tx_ring.producer_lock);
1220
1221         if (flags & XDP_XMIT_FLUSH)
1222                 __tun_xdp_flush_tfile(tfile);
1223
1224         rcu_read_unlock();
1225         return cnt - drops;
1226 }
1227
1228 static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1229 {
1230         struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
1231
1232         if (unlikely(!frame))
1233                 return -EOVERFLOW;
1234
1235         return tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1236 }
1237
1238 static const struct net_device_ops tap_netdev_ops = {
1239         .ndo_uninit             = tun_net_uninit,
1240         .ndo_open               = tun_net_open,
1241         .ndo_stop               = tun_net_close,
1242         .ndo_start_xmit         = tun_net_xmit,
1243         .ndo_fix_features       = tun_net_fix_features,
1244         .ndo_set_rx_mode        = tun_net_mclist,
1245         .ndo_set_mac_address    = eth_mac_addr,
1246         .ndo_validate_addr      = eth_validate_addr,
1247         .ndo_select_queue       = tun_select_queue,
1248         .ndo_features_check     = passthru_features_check,
1249         .ndo_set_rx_headroom    = tun_set_headroom,
1250         .ndo_get_stats64        = dev_get_tstats64,
1251         .ndo_bpf                = tun_xdp,
1252         .ndo_xdp_xmit           = tun_xdp_xmit,
1253         .ndo_change_carrier     = tun_net_change_carrier,
1254 };
1255
1256 static void tun_flow_init(struct tun_struct *tun)
1257 {
1258         int i;
1259
1260         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1261                 INIT_HLIST_HEAD(&tun->flows[i]);
1262
1263         tun->ageing_time = TUN_FLOW_EXPIRE;
1264         timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1265         mod_timer(&tun->flow_gc_timer,
1266                   round_jiffies_up(jiffies + tun->ageing_time));
1267 }
1268
1269 static void tun_flow_uninit(struct tun_struct *tun)
1270 {
1271         del_timer_sync(&tun->flow_gc_timer);
1272         tun_flow_flush(tun);
1273 }
1274
1275 #define MIN_MTU 68
1276 #define MAX_MTU 65535
1277
1278 /* Initialize net device. */
1279 static void tun_net_init(struct net_device *dev)
1280 {
1281         struct tun_struct *tun = netdev_priv(dev);
1282
1283         switch (tun->flags & TUN_TYPE_MASK) {
1284         case IFF_TUN:
1285                 dev->netdev_ops = &tun_netdev_ops;
1286                 dev->header_ops = &ip_tunnel_header_ops;
1287
1288                 /* Point-to-Point TUN Device */
1289                 dev->hard_header_len = 0;
1290                 dev->addr_len = 0;
1291                 dev->mtu = 1500;
1292
1293                 /* Zero header length */
1294                 dev->type = ARPHRD_NONE;
1295                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1296                 break;
1297
1298         case IFF_TAP:
1299                 dev->netdev_ops = &tap_netdev_ops;
1300                 /* Ethernet TAP Device */
1301                 ether_setup(dev);
1302                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1303                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1304
1305                 eth_hw_addr_random(dev);
1306
1307                 break;
1308         }
1309
1310         dev->min_mtu = MIN_MTU;
1311         dev->max_mtu = MAX_MTU - dev->hard_header_len;
1312 }
1313
1314 static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1315 {
1316         struct sock *sk = tfile->socket.sk;
1317
1318         return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1319 }
1320
1321 /* Character device part */
1322
1323 /* Poll */
1324 static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1325 {
1326         struct tun_file *tfile = file->private_data;
1327         struct tun_struct *tun = tun_get(tfile);
1328         struct sock *sk;
1329         __poll_t mask = 0;
1330
1331         if (!tun)
1332                 return EPOLLERR;
1333
1334         sk = tfile->socket.sk;
1335
1336         poll_wait(file, sk_sleep(sk), wait);
1337
1338         if (!ptr_ring_empty(&tfile->tx_ring))
1339                 mask |= EPOLLIN | EPOLLRDNORM;
1340
1341         /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1342          * guarantee EPOLLOUT to be raised by either here or
1343          * tun_sock_write_space(). Then process could get notification
1344          * after it writes to a down device and meets -EIO.
1345          */
1346         if (tun_sock_writeable(tun, tfile) ||
1347             (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1348              tun_sock_writeable(tun, tfile)))
1349                 mask |= EPOLLOUT | EPOLLWRNORM;
1350
1351         if (tun->dev->reg_state != NETREG_REGISTERED)
1352                 mask = EPOLLERR;
1353
1354         tun_put(tun);
1355         return mask;
1356 }
1357
1358 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1359                                             size_t len,
1360                                             const struct iov_iter *it)
1361 {
1362         struct sk_buff *skb;
1363         size_t linear;
1364         int err;
1365         int i;
1366
1367         if (it->nr_segs > MAX_SKB_FRAGS + 1)
1368                 return ERR_PTR(-ENOMEM);
1369
1370         local_bh_disable();
1371         skb = napi_get_frags(&tfile->napi);
1372         local_bh_enable();
1373         if (!skb)
1374                 return ERR_PTR(-ENOMEM);
1375
1376         linear = iov_iter_single_seg_count(it);
1377         err = __skb_grow(skb, linear);
1378         if (err)
1379                 goto free;
1380
1381         skb->len = len;
1382         skb->data_len = len - linear;
1383         skb->truesize += skb->data_len;
1384
1385         for (i = 1; i < it->nr_segs; i++) {
1386                 size_t fragsz = it->iov[i].iov_len;
1387                 struct page *page;
1388                 void *frag;
1389
1390                 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1391                         err = -EINVAL;
1392                         goto free;
1393                 }
1394                 frag = netdev_alloc_frag(fragsz);
1395                 if (!frag) {
1396                         err = -ENOMEM;
1397                         goto free;
1398                 }
1399                 page = virt_to_head_page(frag);
1400                 skb_fill_page_desc(skb, i - 1, page,
1401                                    frag - page_address(page), fragsz);
1402         }
1403
1404         return skb;
1405 free:
1406         /* frees skb and all frags allocated with napi_alloc_frag() */
1407         napi_free_frags(&tfile->napi);
1408         return ERR_PTR(err);
1409 }
1410
1411 /* prepad is the amount to reserve at front.  len is length after that.
1412  * linear is a hint as to how much to copy (usually headers). */
1413 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1414                                      size_t prepad, size_t len,
1415                                      size_t linear, int noblock)
1416 {
1417         struct sock *sk = tfile->socket.sk;
1418         struct sk_buff *skb;
1419         int err;
1420
1421         /* Under a page?  Don't bother with paged skb. */
1422         if (prepad + len < PAGE_SIZE || !linear)
1423                 linear = len;
1424
1425         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1426                                    &err, 0);
1427         if (!skb)
1428                 return ERR_PTR(err);
1429
1430         skb_reserve(skb, prepad);
1431         skb_put(skb, linear);
1432         skb->data_len = len - linear;
1433         skb->len += len - linear;
1434
1435         return skb;
1436 }
1437
1438 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1439                            struct sk_buff *skb, int more)
1440 {
1441         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1442         struct sk_buff_head process_queue;
1443         u32 rx_batched = tun->rx_batched;
1444         bool rcv = false;
1445
1446         if (!rx_batched || (!more && skb_queue_empty(queue))) {
1447                 local_bh_disable();
1448                 skb_record_rx_queue(skb, tfile->queue_index);
1449                 netif_receive_skb(skb);
1450                 local_bh_enable();
1451                 return;
1452         }
1453
1454         spin_lock(&queue->lock);
1455         if (!more || skb_queue_len(queue) == rx_batched) {
1456                 __skb_queue_head_init(&process_queue);
1457                 skb_queue_splice_tail_init(queue, &process_queue);
1458                 rcv = true;
1459         } else {
1460                 __skb_queue_tail(queue, skb);
1461         }
1462         spin_unlock(&queue->lock);
1463
1464         if (rcv) {
1465                 struct sk_buff *nskb;
1466
1467                 local_bh_disable();
1468                 while ((nskb = __skb_dequeue(&process_queue))) {
1469                         skb_record_rx_queue(nskb, tfile->queue_index);
1470                         netif_receive_skb(nskb);
1471                 }
1472                 skb_record_rx_queue(skb, tfile->queue_index);
1473                 netif_receive_skb(skb);
1474                 local_bh_enable();
1475         }
1476 }
1477
1478 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1479                               int len, int noblock, bool zerocopy)
1480 {
1481         if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1482                 return false;
1483
1484         if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1485                 return false;
1486
1487         if (!noblock)
1488                 return false;
1489
1490         if (zerocopy)
1491                 return false;
1492
1493         if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1494             SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1495                 return false;
1496
1497         return true;
1498 }
1499
1500 static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
1501                                        struct page_frag *alloc_frag, char *buf,
1502                                        int buflen, int len, int pad)
1503 {
1504         struct sk_buff *skb = build_skb(buf, buflen);
1505
1506         if (!skb)
1507                 return ERR_PTR(-ENOMEM);
1508
1509         skb_reserve(skb, pad);
1510         skb_put(skb, len);
1511         skb_set_owner_w(skb, tfile->socket.sk);
1512
1513         get_page(alloc_frag->page);
1514         alloc_frag->offset += buflen;
1515
1516         return skb;
1517 }
1518
1519 static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1520                        struct xdp_buff *xdp, u32 act)
1521 {
1522         int err;
1523
1524         switch (act) {
1525         case XDP_REDIRECT:
1526                 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1527                 if (err)
1528                         return err;
1529                 break;
1530         case XDP_TX:
1531                 err = tun_xdp_tx(tun->dev, xdp);
1532                 if (err < 0)
1533                         return err;
1534                 break;
1535         case XDP_PASS:
1536                 break;
1537         default:
1538                 bpf_warn_invalid_xdp_action(act);
1539                 fallthrough;
1540         case XDP_ABORTED:
1541                 trace_xdp_exception(tun->dev, xdp_prog, act);
1542                 fallthrough;
1543         case XDP_DROP:
1544                 atomic_long_inc(&tun->dev->rx_dropped);
1545                 break;
1546         }
1547
1548         return act;
1549 }
1550
1551 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1552                                      struct tun_file *tfile,
1553                                      struct iov_iter *from,
1554                                      struct virtio_net_hdr *hdr,
1555                                      int len, int *skb_xdp)
1556 {
1557         struct page_frag *alloc_frag = &current->task_frag;
1558         struct bpf_prog *xdp_prog;
1559         int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1560         char *buf;
1561         size_t copied;
1562         int pad = TUN_RX_PAD;
1563         int err = 0;
1564
1565         rcu_read_lock();
1566         xdp_prog = rcu_dereference(tun->xdp_prog);
1567         if (xdp_prog)
1568                 pad += XDP_PACKET_HEADROOM;
1569         buflen += SKB_DATA_ALIGN(len + pad);
1570         rcu_read_unlock();
1571
1572         alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1573         if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1574                 return ERR_PTR(-ENOMEM);
1575
1576         buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1577         copied = copy_page_from_iter(alloc_frag->page,
1578                                      alloc_frag->offset + pad,
1579                                      len, from);
1580         if (copied != len)
1581                 return ERR_PTR(-EFAULT);
1582
1583         /* There's a small window that XDP may be set after the check
1584          * of xdp_prog above, this should be rare and for simplicity
1585          * we do XDP on skb in case the headroom is not enough.
1586          */
1587         if (hdr->gso_type || !xdp_prog) {
1588                 *skb_xdp = 1;
1589                 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len,
1590                                        pad);
1591         }
1592
1593         *skb_xdp = 0;
1594
1595         local_bh_disable();
1596         rcu_read_lock();
1597         xdp_prog = rcu_dereference(tun->xdp_prog);
1598         if (xdp_prog) {
1599                 struct xdp_buff xdp;
1600                 u32 act;
1601
1602                 xdp.data_hard_start = buf;
1603                 xdp.data = buf + pad;
1604                 xdp_set_data_meta_invalid(&xdp);
1605                 xdp.data_end = xdp.data + len;
1606                 xdp.rxq = &tfile->xdp_rxq;
1607                 xdp.frame_sz = buflen;
1608
1609                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1610                 if (act == XDP_REDIRECT || act == XDP_TX) {
1611                         get_page(alloc_frag->page);
1612                         alloc_frag->offset += buflen;
1613                 }
1614                 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1615                 if (err < 0) {
1616                         if (act == XDP_REDIRECT || act == XDP_TX)
1617                                 put_page(alloc_frag->page);
1618                         goto out;
1619                 }
1620
1621                 if (err == XDP_REDIRECT)
1622                         xdp_do_flush();
1623                 if (err != XDP_PASS)
1624                         goto out;
1625
1626                 pad = xdp.data - xdp.data_hard_start;
1627                 len = xdp.data_end - xdp.data;
1628         }
1629         rcu_read_unlock();
1630         local_bh_enable();
1631
1632         return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1633
1634 out:
1635         rcu_read_unlock();
1636         local_bh_enable();
1637         return NULL;
1638 }
1639
1640 /* Get packet from user space buffer */
1641 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1642                             void *msg_control, struct iov_iter *from,
1643                             int noblock, bool more)
1644 {
1645         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1646         struct sk_buff *skb;
1647         size_t total_len = iov_iter_count(from);
1648         size_t len = total_len, align = tun->align, linear;
1649         struct virtio_net_hdr gso = { 0 };
1650         int good_linear;
1651         int copylen;
1652         bool zerocopy = false;
1653         int err;
1654         u32 rxhash = 0;
1655         int skb_xdp = 1;
1656         bool frags = tun_napi_frags_enabled(tfile);
1657
1658         if (!(tun->flags & IFF_NO_PI)) {
1659                 if (len < sizeof(pi))
1660                         return -EINVAL;
1661                 len -= sizeof(pi);
1662
1663                 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1664                         return -EFAULT;
1665         }
1666
1667         if (tun->flags & IFF_VNET_HDR) {
1668                 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1669
1670                 if (len < vnet_hdr_sz)
1671                         return -EINVAL;
1672                 len -= vnet_hdr_sz;
1673
1674                 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1675                         return -EFAULT;
1676
1677                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1678                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1679                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1680
1681                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1682                         return -EINVAL;
1683                 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1684         }
1685
1686         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1687                 align += NET_IP_ALIGN;
1688                 if (unlikely(len < ETH_HLEN ||
1689                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1690                         return -EINVAL;
1691         }
1692
1693         good_linear = SKB_MAX_HEAD(align);
1694
1695         if (msg_control) {
1696                 struct iov_iter i = *from;
1697
1698                 /* There are 256 bytes to be copied in skb, so there is
1699                  * enough room for skb expand head in case it is used.
1700                  * The rest of the buffer is mapped from userspace.
1701                  */
1702                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1703                 if (copylen > good_linear)
1704                         copylen = good_linear;
1705                 linear = copylen;
1706                 iov_iter_advance(&i, copylen);
1707                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1708                         zerocopy = true;
1709         }
1710
1711         if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1712                 /* For the packet that is not easy to be processed
1713                  * (e.g gso or jumbo packet), we will do it at after
1714                  * skb was created with generic XDP routine.
1715                  */
1716                 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1717                 if (IS_ERR(skb)) {
1718                         atomic_long_inc(&tun->dev->rx_dropped);
1719                         return PTR_ERR(skb);
1720                 }
1721                 if (!skb)
1722                         return total_len;
1723         } else {
1724                 if (!zerocopy) {
1725                         copylen = len;
1726                         if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1727                                 linear = good_linear;
1728                         else
1729                                 linear = tun16_to_cpu(tun, gso.hdr_len);
1730                 }
1731
1732                 if (frags) {
1733                         mutex_lock(&tfile->napi_mutex);
1734                         skb = tun_napi_alloc_frags(tfile, copylen, from);
1735                         /* tun_napi_alloc_frags() enforces a layout for the skb.
1736                          * If zerocopy is enabled, then this layout will be
1737                          * overwritten by zerocopy_sg_from_iter().
1738                          */
1739                         zerocopy = false;
1740                 } else {
1741                         skb = tun_alloc_skb(tfile, align, copylen, linear,
1742                                             noblock);
1743                 }
1744
1745                 if (IS_ERR(skb)) {
1746                         if (PTR_ERR(skb) != -EAGAIN)
1747                                 atomic_long_inc(&tun->dev->rx_dropped);
1748                         if (frags)
1749                                 mutex_unlock(&tfile->napi_mutex);
1750                         return PTR_ERR(skb);
1751                 }
1752
1753                 if (zerocopy)
1754                         err = zerocopy_sg_from_iter(skb, from);
1755                 else
1756                         err = skb_copy_datagram_from_iter(skb, 0, from, len);
1757
1758                 if (err) {
1759                         err = -EFAULT;
1760 drop:
1761                         atomic_long_inc(&tun->dev->rx_dropped);
1762                         kfree_skb(skb);
1763                         if (frags) {
1764                                 tfile->napi.skb = NULL;
1765                                 mutex_unlock(&tfile->napi_mutex);
1766                         }
1767
1768                         return err;
1769                 }
1770         }
1771
1772         if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1773                 atomic_long_inc(&tun->rx_frame_errors);
1774                 kfree_skb(skb);
1775                 if (frags) {
1776                         tfile->napi.skb = NULL;
1777                         mutex_unlock(&tfile->napi_mutex);
1778                 }
1779
1780                 return -EINVAL;
1781         }
1782
1783         switch (tun->flags & TUN_TYPE_MASK) {
1784         case IFF_TUN:
1785                 if (tun->flags & IFF_NO_PI) {
1786                         u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1787
1788                         switch (ip_version) {
1789                         case 4:
1790                                 pi.proto = htons(ETH_P_IP);
1791                                 break;
1792                         case 6:
1793                                 pi.proto = htons(ETH_P_IPV6);
1794                                 break;
1795                         default:
1796                                 atomic_long_inc(&tun->dev->rx_dropped);
1797                                 kfree_skb(skb);
1798                                 return -EINVAL;
1799                         }
1800                 }
1801
1802                 skb_reset_mac_header(skb);
1803                 skb->protocol = pi.proto;
1804                 skb->dev = tun->dev;
1805                 break;
1806         case IFF_TAP:
1807                 if (frags && !pskb_may_pull(skb, ETH_HLEN)) {
1808                         err = -ENOMEM;
1809                         goto drop;
1810                 }
1811                 skb->protocol = eth_type_trans(skb, tun->dev);
1812                 break;
1813         }
1814
1815         /* copy skb_ubuf_info for callback when skb has no error */
1816         if (zerocopy) {
1817                 skb_shinfo(skb)->destructor_arg = msg_control;
1818                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1819                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1820         } else if (msg_control) {
1821                 struct ubuf_info *uarg = msg_control;
1822                 uarg->callback(uarg, false);
1823         }
1824
1825         skb_reset_network_header(skb);
1826         skb_probe_transport_header(skb);
1827         skb_record_rx_queue(skb, tfile->queue_index);
1828
1829         if (skb_xdp) {
1830                 struct bpf_prog *xdp_prog;
1831                 int ret;
1832
1833                 local_bh_disable();
1834                 rcu_read_lock();
1835                 xdp_prog = rcu_dereference(tun->xdp_prog);
1836                 if (xdp_prog) {
1837                         ret = do_xdp_generic(xdp_prog, skb);
1838                         if (ret != XDP_PASS) {
1839                                 rcu_read_unlock();
1840                                 local_bh_enable();
1841                                 if (frags) {
1842                                         tfile->napi.skb = NULL;
1843                                         mutex_unlock(&tfile->napi_mutex);
1844                                 }
1845                                 return total_len;
1846                         }
1847                 }
1848                 rcu_read_unlock();
1849                 local_bh_enable();
1850         }
1851
1852         /* Compute the costly rx hash only if needed for flow updates.
1853          * We may get a very small possibility of OOO during switching, not
1854          * worth to optimize.
1855          */
1856         if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1857             !tfile->detached)
1858                 rxhash = __skb_get_hash_symmetric(skb);
1859
1860         rcu_read_lock();
1861         if (unlikely(!(tun->dev->flags & IFF_UP))) {
1862                 err = -EIO;
1863                 rcu_read_unlock();
1864                 goto drop;
1865         }
1866
1867         if (frags) {
1868                 u32 headlen;
1869
1870                 /* Exercise flow dissector code path. */
1871                 skb_push(skb, ETH_HLEN);
1872                 headlen = eth_get_headlen(tun->dev, skb->data,
1873                                           skb_headlen(skb));
1874
1875                 if (unlikely(headlen > skb_headlen(skb))) {
1876                         atomic_long_inc(&tun->dev->rx_dropped);
1877                         napi_free_frags(&tfile->napi);
1878                         rcu_read_unlock();
1879                         mutex_unlock(&tfile->napi_mutex);
1880                         WARN_ON(1);
1881                         return -ENOMEM;
1882                 }
1883
1884                 local_bh_disable();
1885                 napi_gro_frags(&tfile->napi);
1886                 local_bh_enable();
1887                 mutex_unlock(&tfile->napi_mutex);
1888         } else if (tfile->napi_enabled) {
1889                 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1890                 int queue_len;
1891
1892                 spin_lock_bh(&queue->lock);
1893                 __skb_queue_tail(queue, skb);
1894                 queue_len = skb_queue_len(queue);
1895                 spin_unlock(&queue->lock);
1896
1897                 if (!more || queue_len > NAPI_POLL_WEIGHT)
1898                         napi_schedule(&tfile->napi);
1899
1900                 local_bh_enable();
1901         } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1902                 tun_rx_batched(tun, tfile, skb, more);
1903         } else {
1904                 netif_rx_ni(skb);
1905         }
1906         rcu_read_unlock();
1907
1908         preempt_disable();
1909         dev_sw_netstats_rx_add(tun->dev, len);
1910         preempt_enable();
1911
1912         if (rxhash)
1913                 tun_flow_update(tun, rxhash, tfile);
1914
1915         return total_len;
1916 }
1917
1918 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1919 {
1920         struct file *file = iocb->ki_filp;
1921         struct tun_file *tfile = file->private_data;
1922         struct tun_struct *tun = tun_get(tfile);
1923         ssize_t result;
1924         int noblock = 0;
1925
1926         if (!tun)
1927                 return -EBADFD;
1928
1929         if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
1930                 noblock = 1;
1931
1932         result = tun_get_user(tun, tfile, NULL, from, noblock, false);
1933
1934         tun_put(tun);
1935         return result;
1936 }
1937
1938 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
1939                                 struct tun_file *tfile,
1940                                 struct xdp_frame *xdp_frame,
1941                                 struct iov_iter *iter)
1942 {
1943         int vnet_hdr_sz = 0;
1944         size_t size = xdp_frame->len;
1945         size_t ret;
1946
1947         if (tun->flags & IFF_VNET_HDR) {
1948                 struct virtio_net_hdr gso = { 0 };
1949
1950                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1951                 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
1952                         return -EINVAL;
1953                 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
1954                              sizeof(gso)))
1955                         return -EFAULT;
1956                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1957         }
1958
1959         ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
1960
1961         preempt_disable();
1962         dev_sw_netstats_tx_add(tun->dev, 1, ret);
1963         preempt_enable();
1964
1965         return ret;
1966 }
1967
1968 /* Put packet to the user space buffer */
1969 static ssize_t tun_put_user(struct tun_struct *tun,
1970                             struct tun_file *tfile,
1971                             struct sk_buff *skb,
1972                             struct iov_iter *iter)
1973 {
1974         struct tun_pi pi = { 0, skb->protocol };
1975         ssize_t total;
1976         int vlan_offset = 0;
1977         int vlan_hlen = 0;
1978         int vnet_hdr_sz = 0;
1979
1980         if (skb_vlan_tag_present(skb))
1981                 vlan_hlen = VLAN_HLEN;
1982
1983         if (tun->flags & IFF_VNET_HDR)
1984                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1985
1986         total = skb->len + vlan_hlen + vnet_hdr_sz;
1987
1988         if (!(tun->flags & IFF_NO_PI)) {
1989                 if (iov_iter_count(iter) < sizeof(pi))
1990                         return -EINVAL;
1991
1992                 total += sizeof(pi);
1993                 if (iov_iter_count(iter) < total) {
1994                         /* Packet will be striped */
1995                         pi.flags |= TUN_PKT_STRIP;
1996                 }
1997
1998                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1999                         return -EFAULT;
2000         }
2001
2002         if (vnet_hdr_sz) {
2003                 struct virtio_net_hdr gso;
2004
2005                 if (iov_iter_count(iter) < vnet_hdr_sz)
2006                         return -EINVAL;
2007
2008                 if (virtio_net_hdr_from_skb(skb, &gso,
2009                                             tun_is_little_endian(tun), true,
2010                                             vlan_hlen)) {
2011                         struct skb_shared_info *sinfo = skb_shinfo(skb);
2012                         pr_err("unexpected GSO type: "
2013                                "0x%x, gso_size %d, hdr_len %d\n",
2014                                sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2015                                tun16_to_cpu(tun, gso.hdr_len));
2016                         print_hex_dump(KERN_ERR, "tun: ",
2017                                        DUMP_PREFIX_NONE,
2018                                        16, 1, skb->head,
2019                                        min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2020                         WARN_ON_ONCE(1);
2021                         return -EINVAL;
2022                 }
2023
2024                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2025                         return -EFAULT;
2026
2027                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2028         }
2029
2030         if (vlan_hlen) {
2031                 int ret;
2032                 struct veth veth;
2033
2034                 veth.h_vlan_proto = skb->vlan_proto;
2035                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2036
2037                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2038
2039                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2040                 if (ret || !iov_iter_count(iter))
2041                         goto done;
2042
2043                 ret = copy_to_iter(&veth, sizeof(veth), iter);
2044                 if (ret != sizeof(veth) || !iov_iter_count(iter))
2045                         goto done;
2046         }
2047
2048         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2049
2050 done:
2051         /* caller is in process context, */
2052         preempt_disable();
2053         dev_sw_netstats_tx_add(tun->dev, 1, skb->len + vlan_hlen);
2054         preempt_enable();
2055
2056         return total;
2057 }
2058
2059 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2060 {
2061         DECLARE_WAITQUEUE(wait, current);
2062         void *ptr = NULL;
2063         int error = 0;
2064
2065         ptr = ptr_ring_consume(&tfile->tx_ring);
2066         if (ptr)
2067                 goto out;
2068         if (noblock) {
2069                 error = -EAGAIN;
2070                 goto out;
2071         }
2072
2073         add_wait_queue(&tfile->socket.wq.wait, &wait);
2074
2075         while (1) {
2076                 set_current_state(TASK_INTERRUPTIBLE);
2077                 ptr = ptr_ring_consume(&tfile->tx_ring);
2078                 if (ptr)
2079                         break;
2080                 if (signal_pending(current)) {
2081                         error = -ERESTARTSYS;
2082                         break;
2083                 }
2084                 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2085                         error = -EFAULT;
2086                         break;
2087                 }
2088
2089                 schedule();
2090         }
2091
2092         __set_current_state(TASK_RUNNING);
2093         remove_wait_queue(&tfile->socket.wq.wait, &wait);
2094
2095 out:
2096         *err = error;
2097         return ptr;
2098 }
2099
2100 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2101                            struct iov_iter *to,
2102                            int noblock, void *ptr)
2103 {
2104         ssize_t ret;
2105         int err;
2106
2107         if (!iov_iter_count(to)) {
2108                 tun_ptr_free(ptr);
2109                 return 0;
2110         }
2111
2112         if (!ptr) {
2113                 /* Read frames from ring */
2114                 ptr = tun_ring_recv(tfile, noblock, &err);
2115                 if (!ptr)
2116                         return err;
2117         }
2118
2119         if (tun_is_xdp_frame(ptr)) {
2120                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2121
2122                 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2123                 xdp_return_frame(xdpf);
2124         } else {
2125                 struct sk_buff *skb = ptr;
2126
2127                 ret = tun_put_user(tun, tfile, skb, to);
2128                 if (unlikely(ret < 0))
2129                         kfree_skb(skb);
2130                 else
2131                         consume_skb(skb);
2132         }
2133
2134         return ret;
2135 }
2136
2137 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2138 {
2139         struct file *file = iocb->ki_filp;
2140         struct tun_file *tfile = file->private_data;
2141         struct tun_struct *tun = tun_get(tfile);
2142         ssize_t len = iov_iter_count(to), ret;
2143         int noblock = 0;
2144
2145         if (!tun)
2146                 return -EBADFD;
2147
2148         if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
2149                 noblock = 1;
2150
2151         ret = tun_do_read(tun, tfile, to, noblock, NULL);
2152         ret = min_t(ssize_t, ret, len);
2153         if (ret > 0)
2154                 iocb->ki_pos = ret;
2155         tun_put(tun);
2156         return ret;
2157 }
2158
2159 static void tun_prog_free(struct rcu_head *rcu)
2160 {
2161         struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2162
2163         bpf_prog_destroy(prog->prog);
2164         kfree(prog);
2165 }
2166
2167 static int __tun_set_ebpf(struct tun_struct *tun,
2168                           struct tun_prog __rcu **prog_p,
2169                           struct bpf_prog *prog)
2170 {
2171         struct tun_prog *old, *new = NULL;
2172
2173         if (prog) {
2174                 new = kmalloc(sizeof(*new), GFP_KERNEL);
2175                 if (!new)
2176                         return -ENOMEM;
2177                 new->prog = prog;
2178         }
2179
2180         spin_lock_bh(&tun->lock);
2181         old = rcu_dereference_protected(*prog_p,
2182                                         lockdep_is_held(&tun->lock));
2183         rcu_assign_pointer(*prog_p, new);
2184         spin_unlock_bh(&tun->lock);
2185
2186         if (old)
2187                 call_rcu(&old->rcu, tun_prog_free);
2188
2189         return 0;
2190 }
2191
2192 static void tun_free_netdev(struct net_device *dev)
2193 {
2194         struct tun_struct *tun = netdev_priv(dev);
2195
2196         BUG_ON(!(list_empty(&tun->disabled)));
2197
2198         free_percpu(dev->tstats);
2199         /* We clear tstats so that tun_set_iff() can tell if
2200          * tun_free_netdev() has been called from register_netdevice().
2201          */
2202         dev->tstats = NULL;
2203
2204         tun_flow_uninit(tun);
2205         security_tun_dev_free_security(tun->security);
2206         __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2207         __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2208 }
2209
2210 static void tun_setup(struct net_device *dev)
2211 {
2212         struct tun_struct *tun = netdev_priv(dev);
2213
2214         tun->owner = INVALID_UID;
2215         tun->group = INVALID_GID;
2216         tun_default_link_ksettings(dev, &tun->link_ksettings);
2217
2218         dev->ethtool_ops = &tun_ethtool_ops;
2219         dev->needs_free_netdev = true;
2220         dev->priv_destructor = tun_free_netdev;
2221         /* We prefer our own queue length */
2222         dev->tx_queue_len = TUN_READQ_SIZE;
2223 }
2224
2225 /* Trivial set of netlink ops to allow deleting tun or tap
2226  * device with netlink.
2227  */
2228 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2229                         struct netlink_ext_ack *extack)
2230 {
2231         NL_SET_ERR_MSG(extack,
2232                        "tun/tap creation via rtnetlink is not supported.");
2233         return -EOPNOTSUPP;
2234 }
2235
2236 static size_t tun_get_size(const struct net_device *dev)
2237 {
2238         BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2239         BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2240
2241         return nla_total_size(sizeof(uid_t)) + /* OWNER */
2242                nla_total_size(sizeof(gid_t)) + /* GROUP */
2243                nla_total_size(sizeof(u8)) + /* TYPE */
2244                nla_total_size(sizeof(u8)) + /* PI */
2245                nla_total_size(sizeof(u8)) + /* VNET_HDR */
2246                nla_total_size(sizeof(u8)) + /* PERSIST */
2247                nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2248                nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2249                nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2250                0;
2251 }
2252
2253 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2254 {
2255         struct tun_struct *tun = netdev_priv(dev);
2256
2257         if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2258                 goto nla_put_failure;
2259         if (uid_valid(tun->owner) &&
2260             nla_put_u32(skb, IFLA_TUN_OWNER,
2261                         from_kuid_munged(current_user_ns(), tun->owner)))
2262                 goto nla_put_failure;
2263         if (gid_valid(tun->group) &&
2264             nla_put_u32(skb, IFLA_TUN_GROUP,
2265                         from_kgid_munged(current_user_ns(), tun->group)))
2266                 goto nla_put_failure;
2267         if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2268                 goto nla_put_failure;
2269         if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2270                 goto nla_put_failure;
2271         if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2272                 goto nla_put_failure;
2273         if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2274                        !!(tun->flags & IFF_MULTI_QUEUE)))
2275                 goto nla_put_failure;
2276         if (tun->flags & IFF_MULTI_QUEUE) {
2277                 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2278                         goto nla_put_failure;
2279                 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2280                                 tun->numdisabled))
2281                         goto nla_put_failure;
2282         }
2283
2284         return 0;
2285
2286 nla_put_failure:
2287         return -EMSGSIZE;
2288 }
2289
2290 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2291         .kind           = DRV_NAME,
2292         .priv_size      = sizeof(struct tun_struct),
2293         .setup          = tun_setup,
2294         .validate       = tun_validate,
2295         .get_size       = tun_get_size,
2296         .fill_info      = tun_fill_info,
2297 };
2298
2299 static void tun_sock_write_space(struct sock *sk)
2300 {
2301         struct tun_file *tfile;
2302         wait_queue_head_t *wqueue;
2303
2304         if (!sock_writeable(sk))
2305                 return;
2306
2307         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2308                 return;
2309
2310         wqueue = sk_sleep(sk);
2311         if (wqueue && waitqueue_active(wqueue))
2312                 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2313                                                 EPOLLWRNORM | EPOLLWRBAND);
2314
2315         tfile = container_of(sk, struct tun_file, sk);
2316         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2317 }
2318
2319 static void tun_put_page(struct tun_page *tpage)
2320 {
2321         if (tpage->page)
2322                 __page_frag_cache_drain(tpage->page, tpage->count);
2323 }
2324
2325 static int tun_xdp_one(struct tun_struct *tun,
2326                        struct tun_file *tfile,
2327                        struct xdp_buff *xdp, int *flush,
2328                        struct tun_page *tpage)
2329 {
2330         unsigned int datasize = xdp->data_end - xdp->data;
2331         struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2332         struct virtio_net_hdr *gso = &hdr->gso;
2333         struct bpf_prog *xdp_prog;
2334         struct sk_buff *skb = NULL;
2335         u32 rxhash = 0, act;
2336         int buflen = hdr->buflen;
2337         int err = 0;
2338         bool skb_xdp = false;
2339         struct page *page;
2340
2341         xdp_prog = rcu_dereference(tun->xdp_prog);
2342         if (xdp_prog) {
2343                 if (gso->gso_type) {
2344                         skb_xdp = true;
2345                         goto build;
2346                 }
2347                 xdp_set_data_meta_invalid(xdp);
2348                 xdp->rxq = &tfile->xdp_rxq;
2349                 xdp->frame_sz = buflen;
2350
2351                 act = bpf_prog_run_xdp(xdp_prog, xdp);
2352                 err = tun_xdp_act(tun, xdp_prog, xdp, act);
2353                 if (err < 0) {
2354                         put_page(virt_to_head_page(xdp->data));
2355                         return err;
2356                 }
2357
2358                 switch (err) {
2359                 case XDP_REDIRECT:
2360                         *flush = true;
2361                         fallthrough;
2362                 case XDP_TX:
2363                         return 0;
2364                 case XDP_PASS:
2365                         break;
2366                 default:
2367                         page = virt_to_head_page(xdp->data);
2368                         if (tpage->page == page) {
2369                                 ++tpage->count;
2370                         } else {
2371                                 tun_put_page(tpage);
2372                                 tpage->page = page;
2373                                 tpage->count = 1;
2374                         }
2375                         return 0;
2376                 }
2377         }
2378
2379 build:
2380         skb = build_skb(xdp->data_hard_start, buflen);
2381         if (!skb) {
2382                 err = -ENOMEM;
2383                 goto out;
2384         }
2385
2386         skb_reserve(skb, xdp->data - xdp->data_hard_start);
2387         skb_put(skb, xdp->data_end - xdp->data);
2388
2389         if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2390                 atomic_long_inc(&tun->rx_frame_errors);
2391                 kfree_skb(skb);
2392                 err = -EINVAL;
2393                 goto out;
2394         }
2395
2396         skb->protocol = eth_type_trans(skb, tun->dev);
2397         skb_reset_network_header(skb);
2398         skb_probe_transport_header(skb);
2399         skb_record_rx_queue(skb, tfile->queue_index);
2400
2401         if (skb_xdp) {
2402                 err = do_xdp_generic(xdp_prog, skb);
2403                 if (err != XDP_PASS)
2404                         goto out;
2405         }
2406
2407         if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2408             !tfile->detached)
2409                 rxhash = __skb_get_hash_symmetric(skb);
2410
2411         netif_receive_skb(skb);
2412
2413         /* No need to disable preemption here since this function is
2414          * always called with bh disabled
2415          */
2416         dev_sw_netstats_rx_add(tun->dev, datasize);
2417
2418         if (rxhash)
2419                 tun_flow_update(tun, rxhash, tfile);
2420
2421 out:
2422         return err;
2423 }
2424
2425 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2426 {
2427         int ret, i;
2428         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2429         struct tun_struct *tun = tun_get(tfile);
2430         struct tun_msg_ctl *ctl = m->msg_control;
2431         struct xdp_buff *xdp;
2432
2433         if (!tun)
2434                 return -EBADFD;
2435
2436         if (ctl && (ctl->type == TUN_MSG_PTR)) {
2437                 struct tun_page tpage;
2438                 int n = ctl->num;
2439                 int flush = 0;
2440
2441                 memset(&tpage, 0, sizeof(tpage));
2442
2443                 local_bh_disable();
2444                 rcu_read_lock();
2445
2446                 for (i = 0; i < n; i++) {
2447                         xdp = &((struct xdp_buff *)ctl->ptr)[i];
2448                         tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2449                 }
2450
2451                 if (flush)
2452                         xdp_do_flush();
2453
2454                 rcu_read_unlock();
2455                 local_bh_enable();
2456
2457                 tun_put_page(&tpage);
2458
2459                 ret = total_len;
2460                 goto out;
2461         }
2462
2463         ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2464                            m->msg_flags & MSG_DONTWAIT,
2465                            m->msg_flags & MSG_MORE);
2466 out:
2467         tun_put(tun);
2468         return ret;
2469 }
2470
2471 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2472                        int flags)
2473 {
2474         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2475         struct tun_struct *tun = tun_get(tfile);
2476         void *ptr = m->msg_control;
2477         int ret;
2478
2479         if (!tun) {
2480                 ret = -EBADFD;
2481                 goto out_free;
2482         }
2483
2484         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2485                 ret = -EINVAL;
2486                 goto out_put_tun;
2487         }
2488         if (flags & MSG_ERRQUEUE) {
2489                 ret = sock_recv_errqueue(sock->sk, m, total_len,
2490                                          SOL_PACKET, TUN_TX_TIMESTAMP);
2491                 goto out;
2492         }
2493         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2494         if (ret > (ssize_t)total_len) {
2495                 m->msg_flags |= MSG_TRUNC;
2496                 ret = flags & MSG_TRUNC ? ret : total_len;
2497         }
2498 out:
2499         tun_put(tun);
2500         return ret;
2501
2502 out_put_tun:
2503         tun_put(tun);
2504 out_free:
2505         tun_ptr_free(ptr);
2506         return ret;
2507 }
2508
2509 static int tun_ptr_peek_len(void *ptr)
2510 {
2511         if (likely(ptr)) {
2512                 if (tun_is_xdp_frame(ptr)) {
2513                         struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2514
2515                         return xdpf->len;
2516                 }
2517                 return __skb_array_len_with_tag(ptr);
2518         } else {
2519                 return 0;
2520         }
2521 }
2522
2523 static int tun_peek_len(struct socket *sock)
2524 {
2525         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2526         struct tun_struct *tun;
2527         int ret = 0;
2528
2529         tun = tun_get(tfile);
2530         if (!tun)
2531                 return 0;
2532
2533         ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2534         tun_put(tun);
2535
2536         return ret;
2537 }
2538
2539 /* Ops structure to mimic raw sockets with tun */
2540 static const struct proto_ops tun_socket_ops = {
2541         .peek_len = tun_peek_len,
2542         .sendmsg = tun_sendmsg,
2543         .recvmsg = tun_recvmsg,
2544 };
2545
2546 static struct proto tun_proto = {
2547         .name           = "tun",
2548         .owner          = THIS_MODULE,
2549         .obj_size       = sizeof(struct tun_file),
2550 };
2551
2552 static int tun_flags(struct tun_struct *tun)
2553 {
2554         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2555 }
2556
2557 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2558                               char *buf)
2559 {
2560         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2561         return sprintf(buf, "0x%x\n", tun_flags(tun));
2562 }
2563
2564 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2565                               char *buf)
2566 {
2567         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2568         return uid_valid(tun->owner)?
2569                 sprintf(buf, "%u\n",
2570                         from_kuid_munged(current_user_ns(), tun->owner)):
2571                 sprintf(buf, "-1\n");
2572 }
2573
2574 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2575                               char *buf)
2576 {
2577         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2578         return gid_valid(tun->group) ?
2579                 sprintf(buf, "%u\n",
2580                         from_kgid_munged(current_user_ns(), tun->group)):
2581                 sprintf(buf, "-1\n");
2582 }
2583
2584 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2585 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2586 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2587
2588 static struct attribute *tun_dev_attrs[] = {
2589         &dev_attr_tun_flags.attr,
2590         &dev_attr_owner.attr,
2591         &dev_attr_group.attr,
2592         NULL
2593 };
2594
2595 static const struct attribute_group tun_attr_group = {
2596         .attrs = tun_dev_attrs
2597 };
2598
2599 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2600 {
2601         struct tun_struct *tun;
2602         struct tun_file *tfile = file->private_data;
2603         struct net_device *dev;
2604         int err;
2605
2606         if (tfile->detached)
2607                 return -EINVAL;
2608
2609         if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2610                 if (!capable(CAP_NET_ADMIN))
2611                         return -EPERM;
2612
2613                 if (!(ifr->ifr_flags & IFF_NAPI) ||
2614                     (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2615                         return -EINVAL;
2616         }
2617
2618         dev = __dev_get_by_name(net, ifr->ifr_name);
2619         if (dev) {
2620                 if (ifr->ifr_flags & IFF_TUN_EXCL)
2621                         return -EBUSY;
2622                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2623                         tun = netdev_priv(dev);
2624                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2625                         tun = netdev_priv(dev);
2626                 else
2627                         return -EINVAL;
2628
2629                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2630                     !!(tun->flags & IFF_MULTI_QUEUE))
2631                         return -EINVAL;
2632
2633                 if (tun_not_capable(tun))
2634                         return -EPERM;
2635                 err = security_tun_dev_open(tun->security);
2636                 if (err < 0)
2637                         return err;
2638
2639                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2640                                  ifr->ifr_flags & IFF_NAPI,
2641                                  ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2642                 if (err < 0)
2643                         return err;
2644
2645                 if (tun->flags & IFF_MULTI_QUEUE &&
2646                     (tun->numqueues + tun->numdisabled > 1)) {
2647                         /* One or more queue has already been attached, no need
2648                          * to initialize the device again.
2649                          */
2650                         netdev_state_change(dev);
2651                         return 0;
2652                 }
2653
2654                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2655                               (ifr->ifr_flags & TUN_FEATURES);
2656
2657                 netdev_state_change(dev);
2658         } else {
2659                 char *name;
2660                 unsigned long flags = 0;
2661                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2662                              MAX_TAP_QUEUES : 1;
2663
2664                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2665                         return -EPERM;
2666                 err = security_tun_dev_create();
2667                 if (err < 0)
2668                         return err;
2669
2670                 /* Set dev type */
2671                 if (ifr->ifr_flags & IFF_TUN) {
2672                         /* TUN device */
2673                         flags |= IFF_TUN;
2674                         name = "tun%d";
2675                 } else if (ifr->ifr_flags & IFF_TAP) {
2676                         /* TAP device */
2677                         flags |= IFF_TAP;
2678                         name = "tap%d";
2679                 } else
2680                         return -EINVAL;
2681
2682                 if (*ifr->ifr_name)
2683                         name = ifr->ifr_name;
2684
2685                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2686                                        NET_NAME_UNKNOWN, tun_setup, queues,
2687                                        queues);
2688
2689                 if (!dev)
2690                         return -ENOMEM;
2691
2692                 dev_net_set(dev, net);
2693                 dev->rtnl_link_ops = &tun_link_ops;
2694                 dev->ifindex = tfile->ifindex;
2695                 dev->sysfs_groups[0] = &tun_attr_group;
2696
2697                 tun = netdev_priv(dev);
2698                 tun->dev = dev;
2699                 tun->flags = flags;
2700                 tun->txflt.count = 0;
2701                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2702
2703                 tun->align = NET_SKB_PAD;
2704                 tun->filter_attached = false;
2705                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2706                 tun->rx_batched = 0;
2707                 RCU_INIT_POINTER(tun->steering_prog, NULL);
2708
2709                 dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
2710                 if (!dev->tstats) {
2711                         err = -ENOMEM;
2712                         goto err_free_dev;
2713                 }
2714
2715                 spin_lock_init(&tun->lock);
2716
2717                 err = security_tun_dev_alloc_security(&tun->security);
2718                 if (err < 0)
2719                         goto err_free_stat;
2720
2721                 tun_net_init(dev);
2722                 tun_flow_init(tun);
2723
2724                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2725                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2726                                    NETIF_F_HW_VLAN_STAG_TX;
2727                 dev->features = dev->hw_features | NETIF_F_LLTX;
2728                 dev->vlan_features = dev->features &
2729                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
2730                                        NETIF_F_HW_VLAN_STAG_TX);
2731
2732                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2733                               (ifr->ifr_flags & TUN_FEATURES);
2734
2735                 INIT_LIST_HEAD(&tun->disabled);
2736                 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI,
2737                                  ifr->ifr_flags & IFF_NAPI_FRAGS, false);
2738                 if (err < 0)
2739                         goto err_free_flow;
2740
2741                 err = register_netdevice(tun->dev);
2742                 if (err < 0)
2743                         goto err_detach;
2744                 /* free_netdev() won't check refcnt, to aovid race
2745                  * with dev_put() we need publish tun after registration.
2746                  */
2747                 rcu_assign_pointer(tfile->tun, tun);
2748         }
2749
2750         netif_carrier_on(tun->dev);
2751
2752         /* Make sure persistent devices do not get stuck in
2753          * xoff state.
2754          */
2755         if (netif_running(tun->dev))
2756                 netif_tx_wake_all_queues(tun->dev);
2757
2758         strcpy(ifr->ifr_name, tun->dev->name);
2759         return 0;
2760
2761 err_detach:
2762         tun_detach_all(dev);
2763         /* We are here because register_netdevice() has failed.
2764          * If register_netdevice() already called tun_free_netdev()
2765          * while dealing with the error, dev->stats has been cleared.
2766          */
2767         if (!dev->tstats)
2768                 goto err_free_dev;
2769
2770 err_free_flow:
2771         tun_flow_uninit(tun);
2772         security_tun_dev_free_security(tun->security);
2773 err_free_stat:
2774         free_percpu(dev->tstats);
2775 err_free_dev:
2776         free_netdev(dev);
2777         return err;
2778 }
2779
2780 static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2781 {
2782         strcpy(ifr->ifr_name, tun->dev->name);
2783
2784         ifr->ifr_flags = tun_flags(tun);
2785
2786 }
2787
2788 /* This is like a cut-down ethtool ops, except done via tun fd so no
2789  * privs required. */
2790 static int set_offload(struct tun_struct *tun, unsigned long arg)
2791 {
2792         netdev_features_t features = 0;
2793
2794         if (arg & TUN_F_CSUM) {
2795                 features |= NETIF_F_HW_CSUM;
2796                 arg &= ~TUN_F_CSUM;
2797
2798                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2799                         if (arg & TUN_F_TSO_ECN) {
2800                                 features |= NETIF_F_TSO_ECN;
2801                                 arg &= ~TUN_F_TSO_ECN;
2802                         }
2803                         if (arg & TUN_F_TSO4)
2804                                 features |= NETIF_F_TSO;
2805                         if (arg & TUN_F_TSO6)
2806                                 features |= NETIF_F_TSO6;
2807                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2808                 }
2809
2810                 arg &= ~TUN_F_UFO;
2811         }
2812
2813         /* This gives the user a way to test for new features in future by
2814          * trying to set them. */
2815         if (arg)
2816                 return -EINVAL;
2817
2818         tun->set_features = features;
2819         tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2820         tun->dev->wanted_features |= features;
2821         netdev_update_features(tun->dev);
2822
2823         return 0;
2824 }
2825
2826 static void tun_detach_filter(struct tun_struct *tun, int n)
2827 {
2828         int i;
2829         struct tun_file *tfile;
2830
2831         for (i = 0; i < n; i++) {
2832                 tfile = rtnl_dereference(tun->tfiles[i]);
2833                 lock_sock(tfile->socket.sk);
2834                 sk_detach_filter(tfile->socket.sk);
2835                 release_sock(tfile->socket.sk);
2836         }
2837
2838         tun->filter_attached = false;
2839 }
2840
2841 static int tun_attach_filter(struct tun_struct *tun)
2842 {
2843         int i, ret = 0;
2844         struct tun_file *tfile;
2845
2846         for (i = 0; i < tun->numqueues; i++) {
2847                 tfile = rtnl_dereference(tun->tfiles[i]);
2848                 lock_sock(tfile->socket.sk);
2849                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2850                 release_sock(tfile->socket.sk);
2851                 if (ret) {
2852                         tun_detach_filter(tun, i);
2853                         return ret;
2854                 }
2855         }
2856
2857         tun->filter_attached = true;
2858         return ret;
2859 }
2860
2861 static void tun_set_sndbuf(struct tun_struct *tun)
2862 {
2863         struct tun_file *tfile;
2864         int i;
2865
2866         for (i = 0; i < tun->numqueues; i++) {
2867                 tfile = rtnl_dereference(tun->tfiles[i]);
2868                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2869         }
2870 }
2871
2872 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2873 {
2874         struct tun_file *tfile = file->private_data;
2875         struct tun_struct *tun;
2876         int ret = 0;
2877
2878         rtnl_lock();
2879
2880         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2881                 tun = tfile->detached;
2882                 if (!tun) {
2883                         ret = -EINVAL;
2884                         goto unlock;
2885                 }
2886                 ret = security_tun_dev_attach_queue(tun->security);
2887                 if (ret < 0)
2888                         goto unlock;
2889                 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2890                                  tun->flags & IFF_NAPI_FRAGS, true);
2891         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2892                 tun = rtnl_dereference(tfile->tun);
2893                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2894                         ret = -EINVAL;
2895                 else
2896                         __tun_detach(tfile, false);
2897         } else
2898                 ret = -EINVAL;
2899
2900         if (ret >= 0)
2901                 netdev_state_change(tun->dev);
2902
2903 unlock:
2904         rtnl_unlock();
2905         return ret;
2906 }
2907
2908 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog __rcu **prog_p,
2909                         void __user *data)
2910 {
2911         struct bpf_prog *prog;
2912         int fd;
2913
2914         if (copy_from_user(&fd, data, sizeof(fd)))
2915                 return -EFAULT;
2916
2917         if (fd == -1) {
2918                 prog = NULL;
2919         } else {
2920                 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
2921                 if (IS_ERR(prog))
2922                         return PTR_ERR(prog);
2923         }
2924
2925         return __tun_set_ebpf(tun, prog_p, prog);
2926 }
2927
2928 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2929                             unsigned long arg, int ifreq_len)
2930 {
2931         struct tun_file *tfile = file->private_data;
2932         struct net *net = sock_net(&tfile->sk);
2933         struct tun_struct *tun;
2934         void __user* argp = (void __user*)arg;
2935         unsigned int ifindex, carrier;
2936         struct ifreq ifr;
2937         kuid_t owner;
2938         kgid_t group;
2939         int sndbuf;
2940         int vnet_hdr_sz;
2941         int le;
2942         int ret;
2943         bool do_notify = false;
2944
2945         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
2946             (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
2947                 if (copy_from_user(&ifr, argp, ifreq_len))
2948                         return -EFAULT;
2949         } else {
2950                 memset(&ifr, 0, sizeof(ifr));
2951         }
2952         if (cmd == TUNGETFEATURES) {
2953                 /* Currently this just means: "what IFF flags are valid?".
2954                  * This is needed because we never checked for invalid flags on
2955                  * TUNSETIFF.
2956                  */
2957                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2958                                 (unsigned int __user*)argp);
2959         } else if (cmd == TUNSETQUEUE) {
2960                 return tun_set_queue(file, &ifr);
2961         } else if (cmd == SIOCGSKNS) {
2962                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2963                         return -EPERM;
2964                 return open_related_ns(&net->ns, get_net_ns);
2965         }
2966
2967         ret = 0;
2968         rtnl_lock();
2969
2970         tun = tun_get(tfile);
2971         if (cmd == TUNSETIFF) {
2972                 ret = -EEXIST;
2973                 if (tun)
2974                         goto unlock;
2975
2976                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2977
2978                 ret = tun_set_iff(net, file, &ifr);
2979
2980                 if (ret)
2981                         goto unlock;
2982
2983                 if (copy_to_user(argp, &ifr, ifreq_len))
2984                         ret = -EFAULT;
2985                 goto unlock;
2986         }
2987         if (cmd == TUNSETIFINDEX) {
2988                 ret = -EPERM;
2989                 if (tun)
2990                         goto unlock;
2991
2992                 ret = -EFAULT;
2993                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2994                         goto unlock;
2995
2996                 ret = 0;
2997                 tfile->ifindex = ifindex;
2998                 goto unlock;
2999         }
3000
3001         ret = -EBADFD;
3002         if (!tun)
3003                 goto unlock;
3004
3005         netif_info(tun, drv, tun->dev, "tun_chr_ioctl cmd %u\n", cmd);
3006
3007         net = dev_net(tun->dev);
3008         ret = 0;
3009         switch (cmd) {
3010         case TUNGETIFF:
3011                 tun_get_iff(tun, &ifr);
3012
3013                 if (tfile->detached)
3014                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
3015                 if (!tfile->socket.sk->sk_filter)
3016                         ifr.ifr_flags |= IFF_NOFILTER;
3017
3018                 if (copy_to_user(argp, &ifr, ifreq_len))
3019                         ret = -EFAULT;
3020                 break;
3021
3022         case TUNSETNOCSUM:
3023                 /* Disable/Enable checksum */
3024
3025                 /* [unimplemented] */
3026                 netif_info(tun, drv, tun->dev, "ignored: set checksum %s\n",
3027                            arg ? "disabled" : "enabled");
3028                 break;
3029
3030         case TUNSETPERSIST:
3031                 /* Disable/Enable persist mode. Keep an extra reference to the
3032                  * module to prevent the module being unprobed.
3033                  */
3034                 if (arg && !(tun->flags & IFF_PERSIST)) {
3035                         tun->flags |= IFF_PERSIST;
3036                         __module_get(THIS_MODULE);
3037                         do_notify = true;
3038                 }
3039                 if (!arg && (tun->flags & IFF_PERSIST)) {
3040                         tun->flags &= ~IFF_PERSIST;
3041                         module_put(THIS_MODULE);
3042                         do_notify = true;
3043                 }
3044
3045                 netif_info(tun, drv, tun->dev, "persist %s\n",
3046                            arg ? "enabled" : "disabled");
3047                 break;
3048
3049         case TUNSETOWNER:
3050                 /* Set owner of the device */
3051                 owner = make_kuid(current_user_ns(), arg);
3052                 if (!uid_valid(owner)) {
3053                         ret = -EINVAL;
3054                         break;
3055                 }
3056                 tun->owner = owner;
3057                 do_notify = true;
3058                 netif_info(tun, drv, tun->dev, "owner set to %u\n",
3059                            from_kuid(&init_user_ns, tun->owner));
3060                 break;
3061
3062         case TUNSETGROUP:
3063                 /* Set group of the device */
3064                 group = make_kgid(current_user_ns(), arg);
3065                 if (!gid_valid(group)) {
3066                         ret = -EINVAL;
3067                         break;
3068                 }
3069                 tun->group = group;
3070                 do_notify = true;
3071                 netif_info(tun, drv, tun->dev, "group set to %u\n",
3072                            from_kgid(&init_user_ns, tun->group));
3073                 break;
3074
3075         case TUNSETLINK:
3076                 /* Only allow setting the type when the interface is down */
3077                 if (tun->dev->flags & IFF_UP) {
3078                         netif_info(tun, drv, tun->dev,
3079                                    "Linktype set failed because interface is up\n");
3080                         ret = -EBUSY;
3081                 } else {
3082                         ret = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE,
3083                                                        tun->dev);
3084                         ret = notifier_to_errno(ret);
3085                         if (ret) {
3086                                 netif_info(tun, drv, tun->dev,
3087                                            "Refused to change device type\n");
3088                                 break;
3089                         }
3090                         tun->dev->type = (int) arg;
3091                         netif_info(tun, drv, tun->dev, "linktype set to %d\n",
3092                                    tun->dev->type);
3093                         call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE,
3094                                                  tun->dev);
3095                 }
3096                 break;
3097
3098         case TUNSETDEBUG:
3099                 tun->msg_enable = (u32)arg;
3100                 break;
3101
3102         case TUNSETOFFLOAD:
3103                 ret = set_offload(tun, arg);
3104                 break;
3105
3106         case TUNSETTXFILTER:
3107                 /* Can be set only for TAPs */
3108                 ret = -EINVAL;
3109                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3110                         break;
3111                 ret = update_filter(&tun->txflt, (void __user *)arg);
3112                 break;
3113
3114         case SIOCGIFHWADDR:
3115                 /* Get hw address */
3116                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3117                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3118                 if (copy_to_user(argp, &ifr, ifreq_len))
3119                         ret = -EFAULT;
3120                 break;
3121
3122         case SIOCSIFHWADDR:
3123                 /* Set hw address */
3124                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr, NULL);
3125                 break;
3126
3127         case TUNGETSNDBUF:
3128                 sndbuf = tfile->socket.sk->sk_sndbuf;
3129                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3130                         ret = -EFAULT;
3131                 break;
3132
3133         case TUNSETSNDBUF:
3134                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3135                         ret = -EFAULT;
3136                         break;
3137                 }
3138                 if (sndbuf <= 0) {
3139                         ret = -EINVAL;
3140                         break;
3141                 }
3142
3143                 tun->sndbuf = sndbuf;
3144                 tun_set_sndbuf(tun);
3145                 break;
3146
3147         case TUNGETVNETHDRSZ:
3148                 vnet_hdr_sz = tun->vnet_hdr_sz;
3149                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3150                         ret = -EFAULT;
3151                 break;
3152
3153         case TUNSETVNETHDRSZ:
3154                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3155                         ret = -EFAULT;
3156                         break;
3157                 }
3158                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3159                         ret = -EINVAL;
3160                         break;
3161                 }
3162
3163                 tun->vnet_hdr_sz = vnet_hdr_sz;
3164                 break;
3165
3166         case TUNGETVNETLE:
3167                 le = !!(tun->flags & TUN_VNET_LE);
3168                 if (put_user(le, (int __user *)argp))
3169                         ret = -EFAULT;
3170                 break;
3171
3172         case TUNSETVNETLE:
3173                 if (get_user(le, (int __user *)argp)) {
3174                         ret = -EFAULT;
3175                         break;
3176                 }
3177                 if (le)
3178                         tun->flags |= TUN_VNET_LE;
3179                 else
3180                         tun->flags &= ~TUN_VNET_LE;
3181                 break;
3182
3183         case TUNGETVNETBE:
3184                 ret = tun_get_vnet_be(tun, argp);
3185                 break;
3186
3187         case TUNSETVNETBE:
3188                 ret = tun_set_vnet_be(tun, argp);
3189                 break;
3190
3191         case TUNATTACHFILTER:
3192                 /* Can be set only for TAPs */
3193                 ret = -EINVAL;
3194                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3195                         break;
3196                 ret = -EFAULT;
3197                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3198                         break;
3199
3200                 ret = tun_attach_filter(tun);
3201                 break;
3202
3203         case TUNDETACHFILTER:
3204                 /* Can be set only for TAPs */
3205                 ret = -EINVAL;
3206                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3207                         break;
3208                 ret = 0;
3209                 tun_detach_filter(tun, tun->numqueues);
3210                 break;
3211
3212         case TUNGETFILTER:
3213                 ret = -EINVAL;
3214                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3215                         break;
3216                 ret = -EFAULT;
3217                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3218                         break;
3219                 ret = 0;
3220                 break;
3221
3222         case TUNSETSTEERINGEBPF:
3223                 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3224                 break;
3225
3226         case TUNSETFILTEREBPF:
3227                 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3228                 break;
3229
3230         case TUNSETCARRIER:
3231                 ret = -EFAULT;
3232                 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3233                         goto unlock;
3234
3235                 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3236                 break;
3237
3238         case TUNGETDEVNETNS:
3239                 ret = -EPERM;
3240                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3241                         goto unlock;
3242                 ret = open_related_ns(&net->ns, get_net_ns);
3243                 break;
3244
3245         default:
3246                 ret = -EINVAL;
3247                 break;
3248         }
3249
3250         if (do_notify)
3251                 netdev_state_change(tun->dev);
3252
3253 unlock:
3254         rtnl_unlock();
3255         if (tun)
3256                 tun_put(tun);
3257         return ret;
3258 }
3259
3260 static long tun_chr_ioctl(struct file *file,
3261                           unsigned int cmd, unsigned long arg)
3262 {
3263         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3264 }
3265
3266 #ifdef CONFIG_COMPAT
3267 static long tun_chr_compat_ioctl(struct file *file,
3268                          unsigned int cmd, unsigned long arg)
3269 {
3270         switch (cmd) {
3271         case TUNSETIFF:
3272         case TUNGETIFF:
3273         case TUNSETTXFILTER:
3274         case TUNGETSNDBUF:
3275         case TUNSETSNDBUF:
3276         case SIOCGIFHWADDR:
3277         case SIOCSIFHWADDR:
3278                 arg = (unsigned long)compat_ptr(arg);
3279                 break;
3280         default:
3281                 arg = (compat_ulong_t)arg;
3282                 break;
3283         }
3284
3285         /*
3286          * compat_ifreq is shorter than ifreq, so we must not access beyond
3287          * the end of that structure. All fields that are used in this
3288          * driver are compatible though, we don't need to convert the
3289          * contents.
3290          */
3291         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3292 }
3293 #endif /* CONFIG_COMPAT */
3294
3295 static int tun_chr_fasync(int fd, struct file *file, int on)
3296 {
3297         struct tun_file *tfile = file->private_data;
3298         int ret;
3299
3300         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3301                 goto out;
3302
3303         if (on) {
3304                 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3305                 tfile->flags |= TUN_FASYNC;
3306         } else
3307                 tfile->flags &= ~TUN_FASYNC;
3308         ret = 0;
3309 out:
3310         return ret;
3311 }
3312
3313 static int tun_chr_open(struct inode *inode, struct file * file)
3314 {
3315         struct net *net = current->nsproxy->net_ns;
3316         struct tun_file *tfile;
3317
3318         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3319                                             &tun_proto, 0);
3320         if (!tfile)
3321                 return -ENOMEM;
3322         if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3323                 sk_free(&tfile->sk);
3324                 return -ENOMEM;
3325         }
3326
3327         mutex_init(&tfile->napi_mutex);
3328         RCU_INIT_POINTER(tfile->tun, NULL);
3329         tfile->flags = 0;
3330         tfile->ifindex = 0;
3331
3332         init_waitqueue_head(&tfile->socket.wq.wait);
3333
3334         tfile->socket.file = file;
3335         tfile->socket.ops = &tun_socket_ops;
3336
3337         sock_init_data(&tfile->socket, &tfile->sk);
3338
3339         tfile->sk.sk_write_space = tun_sock_write_space;
3340         tfile->sk.sk_sndbuf = INT_MAX;
3341
3342         file->private_data = tfile;
3343         INIT_LIST_HEAD(&tfile->next);
3344
3345         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3346
3347         return 0;
3348 }
3349
3350 static int tun_chr_close(struct inode *inode, struct file *file)
3351 {
3352         struct tun_file *tfile = file->private_data;
3353
3354         tun_detach(tfile, true);
3355
3356         return 0;
3357 }
3358
3359 #ifdef CONFIG_PROC_FS
3360 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3361 {
3362         struct tun_file *tfile = file->private_data;
3363         struct tun_struct *tun;
3364         struct ifreq ifr;
3365
3366         memset(&ifr, 0, sizeof(ifr));
3367
3368         rtnl_lock();
3369         tun = tun_get(tfile);
3370         if (tun)
3371                 tun_get_iff(tun, &ifr);
3372         rtnl_unlock();
3373
3374         if (tun)
3375                 tun_put(tun);
3376
3377         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3378 }
3379 #endif
3380
3381 static const struct file_operations tun_fops = {
3382         .owner  = THIS_MODULE,
3383         .llseek = no_llseek,
3384         .read_iter  = tun_chr_read_iter,
3385         .write_iter = tun_chr_write_iter,
3386         .poll   = tun_chr_poll,
3387         .unlocked_ioctl = tun_chr_ioctl,
3388 #ifdef CONFIG_COMPAT
3389         .compat_ioctl = tun_chr_compat_ioctl,
3390 #endif
3391         .open   = tun_chr_open,
3392         .release = tun_chr_close,
3393         .fasync = tun_chr_fasync,
3394 #ifdef CONFIG_PROC_FS
3395         .show_fdinfo = tun_chr_show_fdinfo,
3396 #endif
3397 };
3398
3399 static struct miscdevice tun_miscdev = {
3400         .minor = TUN_MINOR,
3401         .name = "tun",
3402         .nodename = "net/tun",
3403         .fops = &tun_fops,
3404 };
3405
3406 /* ethtool interface */
3407
3408 static void tun_default_link_ksettings(struct net_device *dev,
3409                                        struct ethtool_link_ksettings *cmd)
3410 {
3411         ethtool_link_ksettings_zero_link_mode(cmd, supported);
3412         ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3413         cmd->base.speed         = SPEED_10;
3414         cmd->base.duplex        = DUPLEX_FULL;
3415         cmd->base.port          = PORT_TP;
3416         cmd->base.phy_address   = 0;
3417         cmd->base.autoneg       = AUTONEG_DISABLE;
3418 }
3419
3420 static int tun_get_link_ksettings(struct net_device *dev,
3421                                   struct ethtool_link_ksettings *cmd)
3422 {
3423         struct tun_struct *tun = netdev_priv(dev);
3424
3425         memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3426         return 0;
3427 }
3428
3429 static int tun_set_link_ksettings(struct net_device *dev,
3430                                   const struct ethtool_link_ksettings *cmd)
3431 {
3432         struct tun_struct *tun = netdev_priv(dev);
3433
3434         memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3435         return 0;
3436 }
3437
3438 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3439 {
3440         struct tun_struct *tun = netdev_priv(dev);
3441
3442         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3443         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3444
3445         switch (tun->flags & TUN_TYPE_MASK) {
3446         case IFF_TUN:
3447                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3448                 break;
3449         case IFF_TAP:
3450                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3451                 break;
3452         }
3453 }
3454
3455 static u32 tun_get_msglevel(struct net_device *dev)
3456 {
3457         struct tun_struct *tun = netdev_priv(dev);
3458
3459         return tun->msg_enable;
3460 }
3461
3462 static void tun_set_msglevel(struct net_device *dev, u32 value)
3463 {
3464         struct tun_struct *tun = netdev_priv(dev);
3465
3466         tun->msg_enable = value;
3467 }
3468
3469 static int tun_get_coalesce(struct net_device *dev,
3470                             struct ethtool_coalesce *ec)
3471 {
3472         struct tun_struct *tun = netdev_priv(dev);
3473
3474         ec->rx_max_coalesced_frames = tun->rx_batched;
3475
3476         return 0;
3477 }
3478
3479 static int tun_set_coalesce(struct net_device *dev,
3480                             struct ethtool_coalesce *ec)
3481 {
3482         struct tun_struct *tun = netdev_priv(dev);
3483
3484         if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3485                 tun->rx_batched = NAPI_POLL_WEIGHT;
3486         else
3487                 tun->rx_batched = ec->rx_max_coalesced_frames;
3488
3489         return 0;
3490 }
3491
3492 static const struct ethtool_ops tun_ethtool_ops = {
3493         .supported_coalesce_params = ETHTOOL_COALESCE_RX_MAX_FRAMES,
3494         .get_drvinfo    = tun_get_drvinfo,
3495         .get_msglevel   = tun_get_msglevel,
3496         .set_msglevel   = tun_set_msglevel,
3497         .get_link       = ethtool_op_get_link,
3498         .get_ts_info    = ethtool_op_get_ts_info,
3499         .get_coalesce   = tun_get_coalesce,
3500         .set_coalesce   = tun_set_coalesce,
3501         .get_link_ksettings = tun_get_link_ksettings,
3502         .set_link_ksettings = tun_set_link_ksettings,
3503 };
3504
3505 static int tun_queue_resize(struct tun_struct *tun)
3506 {
3507         struct net_device *dev = tun->dev;
3508         struct tun_file *tfile;
3509         struct ptr_ring **rings;
3510         int n = tun->numqueues + tun->numdisabled;
3511         int ret, i;
3512
3513         rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3514         if (!rings)
3515                 return -ENOMEM;
3516
3517         for (i = 0; i < tun->numqueues; i++) {
3518                 tfile = rtnl_dereference(tun->tfiles[i]);
3519                 rings[i] = &tfile->tx_ring;
3520         }
3521         list_for_each_entry(tfile, &tun->disabled, next)
3522                 rings[i++] = &tfile->tx_ring;
3523
3524         ret = ptr_ring_resize_multiple(rings, n,
3525                                        dev->tx_queue_len, GFP_KERNEL,
3526                                        tun_ptr_free);
3527
3528         kfree(rings);
3529         return ret;
3530 }
3531
3532 static int tun_device_event(struct notifier_block *unused,
3533                             unsigned long event, void *ptr)
3534 {
3535         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3536         struct tun_struct *tun = netdev_priv(dev);
3537         int i;
3538
3539         if (dev->rtnl_link_ops != &tun_link_ops)
3540                 return NOTIFY_DONE;
3541
3542         switch (event) {
3543         case NETDEV_CHANGE_TX_QUEUE_LEN:
3544                 if (tun_queue_resize(tun))
3545                         return NOTIFY_BAD;
3546                 break;
3547         case NETDEV_UP:
3548                 for (i = 0; i < tun->numqueues; i++) {
3549                         struct tun_file *tfile;
3550
3551                         tfile = rtnl_dereference(tun->tfiles[i]);
3552                         tfile->socket.sk->sk_write_space(tfile->socket.sk);
3553                 }
3554                 break;
3555         default:
3556                 break;
3557         }
3558
3559         return NOTIFY_DONE;
3560 }
3561
3562 static struct notifier_block tun_notifier_block __read_mostly = {
3563         .notifier_call  = tun_device_event,
3564 };
3565
3566 static int __init tun_init(void)
3567 {
3568         int ret = 0;
3569
3570         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3571
3572         ret = rtnl_link_register(&tun_link_ops);
3573         if (ret) {
3574                 pr_err("Can't register link_ops\n");
3575                 goto err_linkops;
3576         }
3577
3578         ret = misc_register(&tun_miscdev);
3579         if (ret) {
3580                 pr_err("Can't register misc device %d\n", TUN_MINOR);
3581                 goto err_misc;
3582         }
3583
3584         ret = register_netdevice_notifier(&tun_notifier_block);
3585         if (ret) {
3586                 pr_err("Can't register netdevice notifier\n");
3587                 goto err_notifier;
3588         }
3589
3590         return  0;
3591
3592 err_notifier:
3593         misc_deregister(&tun_miscdev);
3594 err_misc:
3595         rtnl_link_unregister(&tun_link_ops);
3596 err_linkops:
3597         return ret;
3598 }
3599
3600 static void tun_cleanup(void)
3601 {
3602         misc_deregister(&tun_miscdev);
3603         rtnl_link_unregister(&tun_link_ops);
3604         unregister_netdevice_notifier(&tun_notifier_block);
3605 }
3606
3607 /* Get an underlying socket object from tun file.  Returns error unless file is
3608  * attached to a device.  The returned object works like a packet socket, it
3609  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
3610  * holding a reference to the file for as long as the socket is in use. */
3611 struct socket *tun_get_socket(struct file *file)
3612 {
3613         struct tun_file *tfile;
3614         if (file->f_op != &tun_fops)
3615                 return ERR_PTR(-EINVAL);
3616         tfile = file->private_data;
3617         if (!tfile)
3618                 return ERR_PTR(-EBADFD);
3619         return &tfile->socket;
3620 }
3621 EXPORT_SYMBOL_GPL(tun_get_socket);
3622
3623 struct ptr_ring *tun_get_tx_ring(struct file *file)
3624 {
3625         struct tun_file *tfile;
3626
3627         if (file->f_op != &tun_fops)
3628                 return ERR_PTR(-EINVAL);
3629         tfile = file->private_data;
3630         if (!tfile)
3631                 return ERR_PTR(-EBADFD);
3632         return &tfile->tx_ring;
3633 }
3634 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3635
3636 module_init(tun_init);
3637 module_exit(tun_cleanup);
3638 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3639 MODULE_AUTHOR(DRV_COPYRIGHT);
3640 MODULE_LICENSE("GPL");
3641 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3642 MODULE_ALIAS("devname:net/tun");