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 <[email protected]>
   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 <[email protected]> 2005/08/14
  13  *    Add TUNSETLINK ioctl to set the link encapsulation
  14  *
  15  *  Mark Smith <[email protected]>
  16  *    Use eth_random_addr() for tap MAC address.
  17  *
  18  *  Harald Roelle <[email protected]>  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 <[email protected]>
  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 <[email protected]>"
  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/math.h>
  58 #include <linux/nsproxy.h>
  59 #include <linux/virtio_net.h>
  60 #include <linux/rcupdate.h>
  61 #include <net/net_namespace.h>
  62 #include <net/netns/generic.h>
  63 #include <net/rtnetlink.h>
  64 #include <net/sock.h>
  65 #include <net/xdp.h>
  66 #include <net/ip_tunnels.h>
  67 #include <linux/seq_file.h>
  68 #include <linux/uio.h>
  69 #include <linux/skb_array.h>
  70 #include <linux/bpf.h>
  71 #include <linux/bpf_trace.h>
  72 #include <linux/mutex.h>
  73 #include <linux/ieee802154.h>
  74 #include <linux/if_ltalk.h>
  75 #include <uapi/linux/if_fddi.h>
  76 #include <uapi/linux/if_hippi.h>
  77 #include <uapi/linux/if_fc.h>
  78 #include <net/ax25.h>
  79 #include <net/rose.h>
  80 #include <net/6lowpan.h>
  81 #include <net/rps.h>
  82
  83 #include <linux/uaccess.h>
  84 #include <linux/proc_fs.h>
  85
  86 static void tun_default_link_ksettings(struct net_device *dev,
  87                                        struct ethtool_link_ksettings *cmd);
  88
  89 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
  90
  91 /* TUN device flags */
  92
  93 /* IFF_ATTACH_QUEUE is never stored in device flags,
  94  * overload it to mean fasync when stored there.
  95  */
  96 #define TUN_FASYNC      IFF_ATTACH_QUEUE
  97 /* High bits in flags field are unused. */
  98 #define TUN_VNET_LE     0x80000000
  99 #define TUN_VNET_BE     0x40000000
 100
 101 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
 102                       IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
 103
 104 #define GOODCOPY_LEN 128
 105
 106 #define FLT_EXACT_COUNT 8
 107 struct tap_filter {
 108         unsigned int    count;    /* Number of addrs. Zero means disabled */
 109         u32             mask[2];  /* Mask of the hashed addrs */
 110         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 111 };
 112
 113 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
 114  * to max number of VCPUs in guest. */
 115 #define MAX_TAP_QUEUES 256
 116 #define MAX_TAP_FLOWS  4096
 117
 118 #define TUN_FLOW_EXPIRE (3 * HZ)
 119
 120 /* A tun_file connects an open character device to a tuntap netdevice. It
 121  * also contains all socket related structures (except sock_fprog and tap_filter)
 122  * to serve as one transmit queue for tuntap device. The sock_fprog and
 123  * tap_filter were kept in tun_struct since they were used for filtering for the
 124  * netdevice not for a specific queue (at least I didn't see the requirement for
 125  * this).
 126  *
 127  * RCU usage:
 128  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
 129  * other can only be read while rcu_read_lock or rtnl_lock is held.
 130  */
 131 struct tun_file {
 132         struct sock sk;
 133         struct socket socket;
 134         struct tun_struct __rcu *tun;
 135         struct fasync_struct *fasync;
 136         /* only used for fasnyc */
 137         unsigned int flags;
 138         union {
 139                 u16 queue_index;
 140                 unsigned int ifindex;
 141         };
 142         struct napi_struct napi;
 143         bool napi_enabled;
 144         bool napi_frags_enabled;
 145         struct mutex napi_mutex;        /* Protects access to the above napi */
 146         struct list_head next;
 147         struct tun_struct *detached;
 148         struct ptr_ring tx_ring;
 149         struct xdp_rxq_info xdp_rxq;
 150 };
 151
 152 struct tun_page {
 153         struct page *page;
 154         int count;
 155 };
 156
 157 struct tun_flow_entry {
 158         struct hlist_node hash_link;
 159         struct rcu_head rcu;
 160         struct tun_struct *tun;
 161
 162         u32 rxhash;
 163         u32 rps_rxhash;
 164         int queue_index;
 165         unsigned long updated ____cacheline_aligned_in_smp;
 166 };
 167
 168 #define TUN_NUM_FLOW_ENTRIES 1024
 169 #define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
 170
 171 struct tun_prog {
 172         struct rcu_head rcu;
 173         struct bpf_prog *prog;
 174 };
 175
 176 /* Since the socket were moved to tun_file, to preserve the behavior of persist
 177  * device, socket filter, sndbuf and vnet header size were restore when the
 178  * file were attached to a persist device.
 179  */
 180 struct tun_struct {
 181         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
 182         unsigned int            numqueues;
 183         unsigned int            flags;
 184         kuid_t                  owner;
 185         kgid_t                  group;
 186
 187         struct net_device       *dev;
 188         netdev_features_t       set_features;
 189 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 190                           NETIF_F_TSO6 | NETIF_F_GSO_UDP_L4)
 191
 192         int                     align;
 193         int                     vnet_hdr_sz;
 194         int                     sndbuf;
 195         struct tap_filter       txflt;
 196         struct sock_fprog       fprog;
 197         /* protected by rtnl lock */
 198         bool                    filter_attached;
 199         u32                     msg_enable;
 200         spinlock_t lock;
 201         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 202         struct timer_list flow_gc_timer;
 203         unsigned long ageing_time;
 204         unsigned int numdisabled;
 205         struct list_head disabled;
 206         void *security;
 207         u32 flow_count;
 208         u32 rx_batched;
 209         atomic_long_t rx_frame_errors;
 210         struct bpf_prog __rcu *xdp_prog;
 211         struct tun_prog __rcu *steering_prog;
 212         struct tun_prog __rcu *filter_prog;
 213         struct ethtool_link_ksettings link_ksettings;
 214         /* init args */
 215         struct file *file;
 216         struct ifreq *ifr;
 217 };
 218
 219 struct veth {
 220         __be16 h_vlan_proto;
 221         __be16 h_vlan_TCI;
 222 };
 223
 224 static void tun_flow_init(struct tun_struct *tun);
 225 static void tun_flow_uninit(struct tun_struct *tun);
 226
 227 static int tun_napi_receive(struct napi_struct *napi, int budget)
 228 {
 229         struct tun_file *tfile = container_of(napi, struct tun_file, napi);
 230         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
 231         struct sk_buff_head process_queue;
 232         struct sk_buff *skb;
 233         int received = 0;
 234
 235         __skb_queue_head_init(&process_queue);
 236
 237         spin_lock(&queue->lock);
 238         skb_queue_splice_tail_init(queue, &process_queue);
 239         spin_unlock(&queue->lock);
 240
 241         while (received < budget && (skb = __skb_dequeue(&process_queue))) {
 242                 napi_gro_receive(napi, skb);
 243                 ++received;
 244         }
 245
 246         if (!skb_queue_empty(&process_queue)) {
 247                 spin_lock(&queue->lock);
 248                 skb_queue_splice(&process_queue, queue);
 249                 spin_unlock(&queue->lock);
 250         }
 251
 252         return received;
 253 }
 254
 255 static int tun_napi_poll(struct napi_struct *napi, int budget)
 256 {
 257         unsigned int received;
 258
 259         received = tun_napi_receive(napi, budget);
 260
 261         if (received < budget)
 262                 napi_complete_done(napi, received);
 263
 264         return received;
 265 }
 266
 267 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
 268                           bool napi_en, bool napi_frags)
 269 {
 270         tfile->napi_enabled = napi_en;
 271         tfile->napi_frags_enabled = napi_en && napi_frags;
 272         if (napi_en) {
 273                 netif_napi_add_tx(tun->dev, &tfile->napi, tun_napi_poll);
 274                 napi_enable(&tfile->napi);
 275         }
 276 }
 277
 278 static void tun_napi_enable(struct tun_file *tfile)
 279 {
 280         if (tfile->napi_enabled)
 281                 napi_enable(&tfile->napi);
 282 }
 283
 284 static void tun_napi_disable(struct tun_file *tfile)
 285 {
 286         if (tfile->napi_enabled)
 287                 napi_disable(&tfile->napi);
 288 }
 289
 290 static void tun_napi_del(struct tun_file *tfile)
 291 {
 292         if (tfile->napi_enabled)
 293                 netif_napi_del(&tfile->napi);
 294 }
 295
 296 static bool tun_napi_frags_enabled(const struct tun_file *tfile)
 297 {
 298         return tfile->napi_frags_enabled;
 299 }
 300
 301 #ifdef CONFIG_TUN_VNET_CROSS_LE
 302 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 303 {
 304         return tun->flags & TUN_VNET_BE ? false :
 305                 virtio_legacy_is_little_endian();
 306 }
 307
 308 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 309 {
 310         int be = !!(tun->flags & TUN_VNET_BE);
 311
 312         if (put_user(be, argp))
 313                 return -EFAULT;
 314
 315         return 0;
 316 }
 317
 318 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 319 {
 320         int be;
 321
 322         if (get_user(be, argp))
 323                 return -EFAULT;
 324
 325         if (be)
 326                 tun->flags |= TUN_VNET_BE;
 327         else
 328                 tun->flags &= ~TUN_VNET_BE;
 329
 330         return 0;
 331 }
 332 #else
 333 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 334 {
 335         return virtio_legacy_is_little_endian();
 336 }
 337
 338 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 339 {
 340         return -EINVAL;
 341 }
 342
 343 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 344 {
 345         return -EINVAL;
 346 }
 347 #endif /* CONFIG_TUN_VNET_CROSS_LE */
 348
 349 static inline bool tun_is_little_endian(struct tun_struct *tun)
 350 {
 351         return tun->flags & TUN_VNET_LE ||
 352                 tun_legacy_is_little_endian(tun);
 353 }
 354
 355 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
 356 {
 357         return __virtio16_to_cpu(tun_is_little_endian(tun), val);
 358 }
 359
 360 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
 361 {
 362         return __cpu_to_virtio16(tun_is_little_endian(tun), val);
 363 }
 364
 365 static inline u32 tun_hashfn(u32 rxhash)
 366 {
 367         return rxhash & TUN_MASK_FLOW_ENTRIES;
 368 }
 369
 370 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 371 {
 372         struct tun_flow_entry *e;
 373
 374         hlist_for_each_entry_rcu(e, head, hash_link) {
 375                 if (e->rxhash == rxhash)
 376                         return e;
 377         }
 378         return NULL;
 379 }
 380
 381 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 382                                               struct hlist_head *head,
 383                                               u32 rxhash, u16 queue_index)
 384 {
 385         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 386
 387         if (e) {
 388                 netif_info(tun, tx_queued, tun->dev,
 389                            "create flow: hash %u index %u\n",
 390                            rxhash, queue_index);
 391                 e->updated = jiffies;
 392                 e->rxhash = rxhash;
 393                 e->rps_rxhash = 0;
 394                 e->queue_index = queue_index;
 395                 e->tun = tun;
 396                 hlist_add_head_rcu(&e->hash_link, head);
 397                 ++tun->flow_count;
 398         }
 399         return e;
 400 }
 401
 402 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 403 {
 404         netif_info(tun, tx_queued, tun->dev, "delete flow: hash %u index %u\n",
 405                    e->rxhash, e->queue_index);
 406         hlist_del_rcu(&e->hash_link);
 407         kfree_rcu(e, rcu);
 408         --tun->flow_count;
 409 }
 410
 411 static void tun_flow_flush(struct tun_struct *tun)
 412 {
 413         int i;
 414
 415         spin_lock_bh(&tun->lock);
 416         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 417                 struct tun_flow_entry *e;
 418                 struct hlist_node *n;
 419
 420                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 421                         tun_flow_delete(tun, e);
 422         }
 423         spin_unlock_bh(&tun->lock);
 424 }
 425
 426 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 427 {
 428         int i;
 429
 430         spin_lock_bh(&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                         if (e->queue_index == queue_index)
 437                                 tun_flow_delete(tun, e);
 438                 }
 439         }
 440         spin_unlock_bh(&tun->lock);
 441 }
 442
 443 static void tun_flow_cleanup(struct timer_list *t)
 444 {
 445         struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
 446         unsigned long delay = tun->ageing_time;
 447         unsigned long next_timer = jiffies + delay;
 448         unsigned long count = 0;
 449         int i;
 450
 451         spin_lock(&tun->lock);
 452         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 453                 struct tun_flow_entry *e;
 454                 struct hlist_node *n;
 455
 456                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 457                         unsigned long this_timer;
 458
 459                         this_timer = e->updated + delay;
 460                         if (time_before_eq(this_timer, jiffies)) {
 461                                 tun_flow_delete(tun, e);
 462                                 continue;
 463                         }
 464                         count++;
 465                         if (time_before(this_timer, next_timer))
 466                                 next_timer = this_timer;
 467                 }
 468         }
 469
 470         if (count)
 471                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 472         spin_unlock(&tun->lock);
 473 }
 474
 475 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 476                             struct tun_file *tfile)
 477 {
 478         struct hlist_head *head;
 479         struct tun_flow_entry *e;
 480         unsigned long delay = tun->ageing_time;
 481         u16 queue_index = tfile->queue_index;
 482
 483         head = &tun->flows[tun_hashfn(rxhash)];
 484
 485         rcu_read_lock();
 486
 487         e = tun_flow_find(head, rxhash);
 488         if (likely(e)) {
 489                 /* TODO: keep queueing to old queue until it's empty? */
 490                 if (READ_ONCE(e->queue_index) != queue_index)
 491                         WRITE_ONCE(e->queue_index, queue_index);
 492                 if (e->updated != jiffies)
 493                         e->updated = jiffies;
 494                 sock_rps_record_flow_hash(e->rps_rxhash);
 495         } else {
 496                 spin_lock_bh(&tun->lock);
 497                 if (!tun_flow_find(head, rxhash) &&
 498                     tun->flow_count < MAX_TAP_FLOWS)
 499                         tun_flow_create(tun, head, rxhash, queue_index);
 500
 501                 if (!timer_pending(&tun->flow_gc_timer))
 502                         mod_timer(&tun->flow_gc_timer,
 503                                   round_jiffies_up(jiffies + delay));
 504                 spin_unlock_bh(&tun->lock);
 505         }
 506
 507         rcu_read_unlock();
 508 }
 509
 510 /* Save the hash received in the stack receive path and update the
 511  * flow_hash table accordingly.
 512  */
 513 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
 514 {
 515         if (unlikely(e->rps_rxhash != hash))
 516                 e->rps_rxhash = hash;
 517 }
 518
 519 /* We try to identify a flow through its rxhash. The reason that
 520  * we do not check rxq no. is because some cards(e.g 82599), chooses
 521  * the rxq based on the txq where the last packet of the flow comes. As
 522  * the userspace application move between processors, we may get a
 523  * different rxq no. here.
 524  */
 525 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 526 {
 527         struct tun_flow_entry *e;
 528         u32 txq, numqueues;
 529
 530         numqueues = READ_ONCE(tun->numqueues);
 531
 532         txq = __skb_get_hash_symmetric(skb);
 533         e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 534         if (e) {
 535                 tun_flow_save_rps_rxhash(e, txq);
 536                 txq = e->queue_index;
 537         } else {
 538                 txq = reciprocal_scale(txq, numqueues);
 539         }
 540
 541         return txq;
 542 }
 543
 544 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 545 {
 546         struct tun_prog *prog;
 547         u32 numqueues;
 548         u16 ret = 0;
 549
 550         numqueues = READ_ONCE(tun->numqueues);
 551         if (!numqueues)
 552                 return 0;
 553
 554         prog = rcu_dereference(tun->steering_prog);
 555         if (prog)
 556                 ret = bpf_prog_run_clear_cb(prog->prog, skb);
 557
 558         return ret % numqueues;
 559 }
 560
 561 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
 562                             struct net_device *sb_dev)
 563 {
 564         struct tun_struct *tun = netdev_priv(dev);
 565         u16 ret;
 566
 567         rcu_read_lock();
 568         if (rcu_dereference(tun->steering_prog))
 569                 ret = tun_ebpf_select_queue(tun, skb);
 570         else
 571                 ret = tun_automq_select_queue(tun, skb);
 572         rcu_read_unlock();
 573
 574         return ret;
 575 }
 576
 577 static inline bool tun_not_capable(struct tun_struct *tun)
 578 {
 579         const struct cred *cred = current_cred();
 580         struct net *net = dev_net(tun->dev);
 581
 582         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 583                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 584                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 585 }
 586
 587 static void tun_set_real_num_queues(struct tun_struct *tun)
 588 {
 589         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 590         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 591 }
 592
 593 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 594 {
 595         tfile->detached = tun;
 596         list_add_tail(&tfile->next, &tun->disabled);
 597         ++tun->numdisabled;
 598 }
 599
 600 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 601 {
 602         struct tun_struct *tun = tfile->detached;
 603
 604         tfile->detached = NULL;
 605         list_del_init(&tfile->next);
 606         --tun->numdisabled;
 607         return tun;
 608 }
 609
 610 void tun_ptr_free(void *ptr)
 611 {
 612         if (!ptr)
 613                 return;
 614         if (tun_is_xdp_frame(ptr)) {
 615                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
 616
 617                 xdp_return_frame(xdpf);
 618         } else {
 619                 __skb_array_destroy_skb(ptr);
 620         }
 621 }
 622 EXPORT_SYMBOL_GPL(tun_ptr_free);
 623
 624 static void tun_queue_purge(struct tun_file *tfile)
 625 {
 626         void *ptr;
 627
 628         while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
 629                 tun_ptr_free(ptr);
 630
 631         skb_queue_purge(&tfile->sk.sk_write_queue);
 632         skb_queue_purge(&tfile->sk.sk_error_queue);
 633 }
 634
 635 static void __tun_detach(struct tun_file *tfile, bool clean)
 636 {
 637         struct tun_file *ntfile;
 638         struct tun_struct *tun;
 639
 640         tun = rtnl_dereference(tfile->tun);
 641
 642         if (tun && clean) {
 643                 if (!tfile->detached)
 644                         tun_napi_disable(tfile);
 645                 tun_napi_del(tfile);
 646         }
 647
 648         if (tun && !tfile->detached) {
 649                 u16 index = tfile->queue_index;
 650                 BUG_ON(index >= tun->numqueues);
 651
 652                 rcu_assign_pointer(tun->tfiles[index],
 653                                    tun->tfiles[tun->numqueues - 1]);
 654                 ntfile = rtnl_dereference(tun->tfiles[index]);
 655                 ntfile->queue_index = index;
 656                 ntfile->xdp_rxq.queue_index = index;
 657                 rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
 658                                    NULL);
 659
 660                 --tun->numqueues;
 661                 if (clean) {
 662                         RCU_INIT_POINTER(tfile->tun, NULL);
 663                         sock_put(&tfile->sk);
 664                 } else {
 665                         tun_disable_queue(tun, tfile);
 666                         tun_napi_disable(tfile);
 667                 }
 668
 669                 synchronize_net();
 670                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 671                 /* Drop read queue */
 672                 tun_queue_purge(tfile);
 673                 tun_set_real_num_queues(tun);
 674         } else if (tfile->detached && clean) {
 675                 tun = tun_enable_queue(tfile);
 676                 sock_put(&tfile->sk);
 677         }
 678
 679         if (clean) {
 680                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 681                         netif_carrier_off(tun->dev);
 682
 683                         if (!(tun->flags & IFF_PERSIST) &&
 684                             tun->dev->reg_state == NETREG_REGISTERED)
 685                                 unregister_netdevice(tun->dev);
 686                 }
 687                 if (tun)
 688                         xdp_rxq_info_unreg(&tfile->xdp_rxq);
 689                 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
 690         }
 691 }
 692
 693 static void tun_detach(struct tun_file *tfile, bool clean)
 694 {
 695         struct tun_struct *tun;
 696         struct net_device *dev;
 697
 698         rtnl_lock();
 699         tun = rtnl_dereference(tfile->tun);
 700         dev = tun ? tun->dev : NULL;
 701         __tun_detach(tfile, clean);
 702         if (dev)
 703                 netdev_state_change(dev);
 704         rtnl_unlock();
 705
 706         if (clean)
 707                 sock_put(&tfile->sk);
 708 }
 709
 710 static void tun_detach_all(struct net_device *dev)
 711 {
 712         struct tun_struct *tun = netdev_priv(dev);
 713         struct tun_file *tfile, *tmp;
 714         int i, n = tun->numqueues;
 715
 716         for (i = 0; i < n; i++) {
 717                 tfile = rtnl_dereference(tun->tfiles[i]);
 718                 BUG_ON(!tfile);
 719                 tun_napi_disable(tfile);
 720                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 721                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 722                 RCU_INIT_POINTER(tfile->tun, NULL);
 723                 --tun->numqueues;
 724         }
 725         list_for_each_entry(tfile, &tun->disabled, next) {
 726                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 727                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 728                 RCU_INIT_POINTER(tfile->tun, NULL);
 729         }
 730         BUG_ON(tun->numqueues != 0);
 731
 732         synchronize_net();
 733         for (i = 0; i < n; i++) {
 734                 tfile = rtnl_dereference(tun->tfiles[i]);
 735                 tun_napi_del(tfile);
 736                 /* Drop read queue */
 737                 tun_queue_purge(tfile);
 738                 xdp_rxq_info_unreg(&tfile->xdp_rxq);
 739                 sock_put(&tfile->sk);
 740         }
 741         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 742                 tun_napi_del(tfile);
 743                 tun_enable_queue(tfile);
 744                 tun_queue_purge(tfile);
 745                 xdp_rxq_info_unreg(&tfile->xdp_rxq);
 746                 sock_put(&tfile->sk);
 747         }
 748         BUG_ON(tun->numdisabled != 0);
 749
 750         if (tun->flags & IFF_PERSIST)
 751                 module_put(THIS_MODULE);
 752 }
 753
 754 static int tun_attach(struct tun_struct *tun, struct file *file,
 755                       bool skip_filter, bool napi, bool napi_frags,
 756                       bool publish_tun)
 757 {
 758         struct tun_file *tfile = file->private_data;
 759         struct net_device *dev = tun->dev;
 760         int err;
 761
 762         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 763         if (err < 0)
 764                 goto out;
 765
 766         err = -EINVAL;
 767         if (rtnl_dereference(tfile->tun) && !tfile->detached)
 768                 goto out;
 769
 770         err = -EBUSY;
 771         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
 772                 goto out;
 773
 774         err = -E2BIG;
 775         if (!tfile->detached &&
 776             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 777                 goto out;
 778
 779         err = 0;
 780
 781         /* Re-attach the filter to persist device */
 782         if (!skip_filter && (tun->filter_attached == true)) {
 783                 lock_sock(tfile->socket.sk);
 784                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 785                 release_sock(tfile->socket.sk);
 786                 if (!err)
 787                         goto out;
 788         }
 789
 790         if (!tfile->detached &&
 791             ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
 792                             GFP_KERNEL, tun_ptr_free)) {
 793                 err = -ENOMEM;
 794                 goto out;
 795         }
 796
 797         tfile->queue_index = tun->numqueues;
 798         tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
 799
 800         if (tfile->detached) {
 801                 /* Re-attach detached tfile, updating XDP queue_index */
 802                 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
 803
 804                 if (tfile->xdp_rxq.queue_index    != tfile->queue_index)
 805                         tfile->xdp_rxq.queue_index = tfile->queue_index;
 806         } else {
 807                 /* Setup XDP RX-queue info, for new tfile getting attached */
 808                 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
 809                                        tun->dev, tfile->queue_index, 0);
 810                 if (err < 0)
 811                         goto out;
 812                 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
 813                                                  MEM_TYPE_PAGE_SHARED, NULL);
 814                 if (err < 0) {
 815                         xdp_rxq_info_unreg(&tfile->xdp_rxq);
 816                         goto out;
 817                 }
 818                 err = 0;
 819         }
 820
 821         if (tfile->detached) {
 822                 tun_enable_queue(tfile);
 823                 tun_napi_enable(tfile);
 824         } else {
 825                 sock_hold(&tfile->sk);
 826                 tun_napi_init(tun, tfile, napi, napi_frags);
 827         }
 828
 829         if (rtnl_dereference(tun->xdp_prog))
 830                 sock_set_flag(&tfile->sk, SOCK_XDP);
 831
 832         /* device is allowed to go away first, so no need to hold extra
 833          * refcnt.
 834          */
 835
 836         /* Publish tfile->tun and tun->tfiles only after we've fully
 837          * initialized tfile; otherwise we risk using half-initialized
 838          * object.
 839          */
 840         if (publish_tun)
 841                 rcu_assign_pointer(tfile->tun, tun);
 842         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 843         tun->numqueues++;
 844         tun_set_real_num_queues(tun);
 845 out:
 846         return err;
 847 }
 848
 849 static struct tun_struct *tun_get(struct tun_file *tfile)
 850 {
 851         struct tun_struct *tun;
 852
 853         rcu_read_lock();
 854         tun = rcu_dereference(tfile->tun);
 855         if (tun)
 856                 dev_hold(tun->dev);
 857         rcu_read_unlock();
 858
 859         return tun;
 860 }
 861
 862 static void tun_put(struct tun_struct *tun)
 863 {
 864         dev_put(tun->dev);
 865 }
 866
 867 /* TAP filtering */
 868 static void addr_hash_set(u32 *mask, const u8 *addr)
 869 {
 870         int n = ether_crc(ETH_ALEN, addr) >> 26;
 871         mask[n >> 5] |= (1 << (n & 31));
 872 }
 873
 874 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 875 {
 876         int n = ether_crc(ETH_ALEN, addr) >> 26;
 877         return mask[n >> 5] & (1 << (n & 31));
 878 }
 879
 880 static int update_filter(struct tap_filter *filter, void __user *arg)
 881 {
 882         struct { u8 u[ETH_ALEN]; } *addr;
 883         struct tun_filter uf;
 884         int err, alen, n, nexact;
 885
 886         if (copy_from_user(&uf, arg, sizeof(uf)))
 887                 return -EFAULT;
 888
 889         if (!uf.count) {
 890                 /* Disabled */
 891                 filter->count = 0;
 892                 return 0;
 893         }
 894
 895         alen = ETH_ALEN * uf.count;
 896         addr = memdup_user(arg + sizeof(uf), alen);
 897         if (IS_ERR(addr))
 898                 return PTR_ERR(addr);
 899
 900         /* The filter is updated without holding any locks. Which is
 901          * perfectly safe. We disable it first and in the worst
 902          * case we'll accept a few undesired packets. */
 903         filter->count = 0;
 904         wmb();
 905
 906         /* Use first set of addresses as an exact filter */
 907         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 908                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 909
 910         nexact = n;
 911
 912         /* Remaining multicast addresses are hashed,
 913          * unicast will leave the filter disabled. */
 914         memset(filter->mask, 0, sizeof(filter->mask));
 915         for (; n < uf.count; n++) {
 916                 if (!is_multicast_ether_addr(addr[n].u)) {
 917                         err = 0; /* no filter */
 918                         goto free_addr;
 919                 }
 920                 addr_hash_set(filter->mask, addr[n].u);
 921         }
 922
 923         /* For ALLMULTI just set the mask to all ones.
 924          * This overrides the mask populated above. */
 925         if ((uf.flags & TUN_FLT_ALLMULTI))
 926                 memset(filter->mask, ~0, sizeof(filter->mask));
 927
 928         /* Now enable the filter */
 929         wmb();
 930         filter->count = nexact;
 931
 932         /* Return the number of exact filters */
 933         err = nexact;
 934 free_addr:
 935         kfree(addr);
 936         return err;
 937 }
 938
 939 /* Returns: 0 - drop, !=0 - accept */
 940 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 941 {
 942         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 943          * at this point. */
 944         struct ethhdr *eh = (struct ethhdr *) skb->data;
 945         int i;
 946
 947         /* Exact match */
 948         for (i = 0; i < filter->count; i++)
 949                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 950                         return 1;
 951
 952         /* Inexact match (multicast only) */
 953         if (is_multicast_ether_addr(eh->h_dest))
 954                 return addr_hash_test(filter->mask, eh->h_dest);
 955
 956         return 0;
 957 }
 958
 959 /*
 960  * Checks whether the packet is accepted or not.
 961  * Returns: 0 - drop, !=0 - accept
 962  */
 963 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 964 {
 965         if (!filter->count)
 966                 return 1;
 967
 968         return run_filter(filter, skb);
 969 }
 970
 971 /* Network device part of the driver */
 972
 973 static const struct ethtool_ops tun_ethtool_ops;
 974
 975 static int tun_net_init(struct net_device *dev)
 976 {
 977         struct tun_struct *tun = netdev_priv(dev);
 978         struct ifreq *ifr = tun->ifr;
 979         int err;
 980
 981         spin_lock_init(&tun->lock);
 982
 983         err = security_tun_dev_alloc_security(&tun->security);
 984         if (err < 0)
 985                 return err;
 986
 987         tun_flow_init(tun);
 988
 989         dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
 990         dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
 991                            TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
 992                            NETIF_F_HW_VLAN_STAG_TX;
 993         dev->features = dev->hw_features | NETIF_F_LLTX;
 994         dev->vlan_features = dev->features &
 995                              ~(NETIF_F_HW_VLAN_CTAG_TX |
 996                                NETIF_F_HW_VLAN_STAG_TX);
 997
 998         tun->flags = (tun->flags & ~TUN_FEATURES) |
 999                       (ifr->ifr_flags & TUN_FEATURES);
1000
1001         INIT_LIST_HEAD(&tun->disabled);
1002         err = tun_attach(tun, tun->file, false, ifr->ifr_flags & IFF_NAPI,
1003                          ifr->ifr_flags & IFF_NAPI_FRAGS, false);
1004         if (err < 0) {
1005                 tun_flow_uninit(tun);
1006                 security_tun_dev_free_security(tun->security);
1007                 return err;
1008         }
1009         return 0;
1010 }
1011
1012 /* Net device detach from fd. */
1013 static void tun_net_uninit(struct net_device *dev)
1014 {
1015         tun_detach_all(dev);
1016 }
1017
1018 /* Net device open. */
1019 static int tun_net_open(struct net_device *dev)
1020 {
1021         netif_tx_start_all_queues(dev);
1022
1023         return 0;
1024 }
1025
1026 /* Net device close. */
1027 static int tun_net_close(struct net_device *dev)
1028 {
1029         netif_tx_stop_all_queues(dev);
1030         return 0;
1031 }
1032
1033 /* Net device start xmit */
1034 static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1035 {
1036 #ifdef CONFIG_RPS
1037         if (tun->numqueues == 1 && static_branch_unlikely(&rps_needed)) {
1038                 /* Select queue was not called for the skbuff, so we extract the
1039                  * RPS hash and save it into the flow_table here.
1040                  */
1041                 struct tun_flow_entry *e;
1042                 __u32 rxhash;
1043
1044                 rxhash = __skb_get_hash_symmetric(skb);
1045                 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
1046                 if (e)
1047                         tun_flow_save_rps_rxhash(e, rxhash);
1048         }
1049 #endif
1050 }
1051
1052 static unsigned int run_ebpf_filter(struct tun_struct *tun,
1053                                     struct sk_buff *skb,
1054                                     int len)
1055 {
1056         struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1057
1058         if (prog)
1059                 len = bpf_prog_run_clear_cb(prog->prog, skb);
1060
1061         return len;
1062 }
1063
1064 /* Net device start xmit */
1065 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1066 {
1067         struct tun_struct *tun = netdev_priv(dev);
1068         enum skb_drop_reason drop_reason;
1069         int txq = skb->queue_mapping;
1070         struct netdev_queue *queue;
1071         struct tun_file *tfile;
1072         int len = skb->len;
1073
1074         rcu_read_lock();
1075         tfile = rcu_dereference(tun->tfiles[txq]);
1076
1077         /* Drop packet if interface is not attached */
1078         if (!tfile) {
1079                 drop_reason = SKB_DROP_REASON_DEV_READY;
1080                 goto drop;
1081         }
1082
1083         if (!rcu_dereference(tun->steering_prog))
1084                 tun_automq_xmit(tun, skb);
1085
1086         netif_info(tun, tx_queued, tun->dev, "%s %d\n", __func__, skb->len);
1087
1088         /* Drop if the filter does not like it.
1089          * This is a noop if the filter is disabled.
1090          * Filter can be enabled only for the TAP devices. */
1091         if (!check_filter(&tun->txflt, skb)) {
1092                 drop_reason = SKB_DROP_REASON_TAP_TXFILTER;
1093                 goto drop;
1094         }
1095
1096         if (tfile->socket.sk->sk_filter &&
1097             sk_filter(tfile->socket.sk, skb)) {
1098                 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
1099                 goto drop;
1100         }
1101
1102         len = run_ebpf_filter(tun, skb, len);
1103         if (len == 0) {
1104                 drop_reason = SKB_DROP_REASON_TAP_FILTER;
1105                 goto drop;
1106         }
1107
1108         if (pskb_trim(skb, len)) {
1109                 drop_reason = SKB_DROP_REASON_NOMEM;
1110                 goto drop;
1111         }
1112
1113         if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) {
1114                 drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
1115                 goto drop;
1116         }
1117
1118         skb_tx_timestamp(skb);
1119
1120         /* Orphan the skb - required as we might hang on to it
1121          * for indefinite time.
1122          */
1123         skb_orphan(skb);
1124
1125         nf_reset_ct(skb);
1126
1127         if (ptr_ring_produce(&tfile->tx_ring, skb)) {
1128                 drop_reason = SKB_DROP_REASON_FULL_RING;
1129                 goto drop;
1130         }
1131
1132         /* NETIF_F_LLTX requires to do our own update of trans_start */
1133         queue = netdev_get_tx_queue(dev, txq);
1134         txq_trans_cond_update(queue);
1135
1136         /* Notify and wake up reader process */
1137         if (tfile->flags & TUN_FASYNC)
1138                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1139         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1140
1141         rcu_read_unlock();
1142         return NETDEV_TX_OK;
1143
1144 drop:
1145         dev_core_stats_tx_dropped_inc(dev);
1146         skb_tx_error(skb);
1147         kfree_skb_reason(skb, drop_reason);
1148         rcu_read_unlock();
1149         return NET_XMIT_DROP;
1150 }
1151
1152 static void tun_net_mclist(struct net_device *dev)
1153 {
1154         /*
1155          * This callback is supposed to deal with mc filter in
1156          * _rx_ path and has nothing to do with the _tx_ path.
1157          * In rx path we always accept everything userspace gives us.
1158          */
1159 }
1160
1161 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1162         netdev_features_t features)
1163 {
1164         struct tun_struct *tun = netdev_priv(dev);
1165
1166         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1167 }
1168
1169 static void tun_set_headroom(struct net_device *dev, int new_hr)
1170 {
1171         struct tun_struct *tun = netdev_priv(dev);
1172
1173         if (new_hr < NET_SKB_PAD)
1174                 new_hr = NET_SKB_PAD;
1175
1176         tun->align = new_hr;
1177 }
1178
1179 static void
1180 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1181 {
1182         struct tun_struct *tun = netdev_priv(dev);
1183
1184         dev_get_tstats64(dev, stats);
1185
1186         stats->rx_frame_errors +=
1187                 (unsigned long)atomic_long_read(&tun->rx_frame_errors);
1188 }
1189
1190 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1191                        struct netlink_ext_ack *extack)
1192 {
1193         struct tun_struct *tun = netdev_priv(dev);
1194         struct tun_file *tfile;
1195         struct bpf_prog *old_prog;
1196         int i;
1197
1198         old_prog = rtnl_dereference(tun->xdp_prog);
1199         rcu_assign_pointer(tun->xdp_prog, prog);
1200         if (old_prog)
1201                 bpf_prog_put(old_prog);
1202
1203         for (i = 0; i < tun->numqueues; i++) {
1204                 tfile = rtnl_dereference(tun->tfiles[i]);
1205                 if (prog)
1206                         sock_set_flag(&tfile->sk, SOCK_XDP);
1207                 else
1208                         sock_reset_flag(&tfile->sk, SOCK_XDP);
1209         }
1210         list_for_each_entry(tfile, &tun->disabled, next) {
1211                 if (prog)
1212                         sock_set_flag(&tfile->sk, SOCK_XDP);
1213                 else
1214                         sock_reset_flag(&tfile->sk, SOCK_XDP);
1215         }
1216
1217         return 0;
1218 }
1219
1220 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1221 {
1222         switch (xdp->command) {
1223         case XDP_SETUP_PROG:
1224                 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1225         default:
1226                 return -EINVAL;
1227         }
1228 }
1229
1230 static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1231 {
1232         if (new_carrier) {
1233                 struct tun_struct *tun = netdev_priv(dev);
1234
1235                 if (!tun->numqueues)
1236                         return -EPERM;
1237
1238                 netif_carrier_on(dev);
1239         } else {
1240                 netif_carrier_off(dev);
1241         }
1242         return 0;
1243 }
1244
1245 static const struct net_device_ops tun_netdev_ops = {
1246         .ndo_init               = tun_net_init,
1247         .ndo_uninit             = tun_net_uninit,
1248         .ndo_open               = tun_net_open,
1249         .ndo_stop               = tun_net_close,
1250         .ndo_start_xmit         = tun_net_xmit,
1251         .ndo_fix_features       = tun_net_fix_features,
1252         .ndo_select_queue       = tun_select_queue,
1253         .ndo_set_rx_headroom    = tun_set_headroom,
1254         .ndo_get_stats64        = tun_net_get_stats64,
1255         .ndo_change_carrier     = tun_net_change_carrier,
1256 };
1257
1258 static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1259 {
1260         /* Notify and wake up reader process */
1261         if (tfile->flags & TUN_FASYNC)
1262                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1263         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1264 }
1265
1266 static int tun_xdp_xmit(struct net_device *dev, int n,
1267                         struct xdp_frame **frames, u32 flags)
1268 {
1269         struct tun_struct *tun = netdev_priv(dev);
1270         struct tun_file *tfile;
1271         u32 numqueues;
1272         int nxmit = 0;
1273         int i;
1274
1275         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1276                 return -EINVAL;
1277
1278         rcu_read_lock();
1279
1280 resample:
1281         numqueues = READ_ONCE(tun->numqueues);
1282         if (!numqueues) {
1283                 rcu_read_unlock();
1284                 return -ENXIO; /* Caller will free/return all frames */
1285         }
1286
1287         tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1288                                             numqueues]);
1289         if (unlikely(!tfile))
1290                 goto resample;
1291
1292         spin_lock(&tfile->tx_ring.producer_lock);
1293         for (i = 0; i < n; i++) {
1294                 struct xdp_frame *xdp = frames[i];
1295                 /* Encode the XDP flag into lowest bit for consumer to differ
1296                  * XDP buffer from sk_buff.
1297                  */
1298                 void *frame = tun_xdp_to_ptr(xdp);
1299
1300                 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1301                         dev_core_stats_tx_dropped_inc(dev);
1302                         break;
1303                 }
1304                 nxmit++;
1305         }
1306         spin_unlock(&tfile->tx_ring.producer_lock);
1307
1308         if (flags & XDP_XMIT_FLUSH)
1309                 __tun_xdp_flush_tfile(tfile);
1310
1311         rcu_read_unlock();
1312         return nxmit;
1313 }
1314
1315 static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1316 {
1317         struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
1318         int nxmit;
1319
1320         if (unlikely(!frame))
1321                 return -EOVERFLOW;
1322
1323         nxmit = tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1324         if (!nxmit)
1325                 xdp_return_frame_rx_napi(frame);
1326         return nxmit;
1327 }
1328
1329 static const struct net_device_ops tap_netdev_ops = {
1330         .ndo_init               = tun_net_init,
1331         .ndo_uninit             = tun_net_uninit,
1332         .ndo_open               = tun_net_open,
1333         .ndo_stop               = tun_net_close,
1334         .ndo_start_xmit         = tun_net_xmit,
1335         .ndo_fix_features       = tun_net_fix_features,
1336         .ndo_set_rx_mode        = tun_net_mclist,
1337         .ndo_set_mac_address    = eth_mac_addr,
1338         .ndo_validate_addr      = eth_validate_addr,
1339         .ndo_select_queue       = tun_select_queue,
1340         .ndo_features_check     = passthru_features_check,
1341         .ndo_set_rx_headroom    = tun_set_headroom,
1342         .ndo_bpf                = tun_xdp,
1343         .ndo_xdp_xmit           = tun_xdp_xmit,
1344         .ndo_change_carrier     = tun_net_change_carrier,
1345 };
1346
1347 static void tun_flow_init(struct tun_struct *tun)
1348 {
1349         int i;
1350
1351         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1352                 INIT_HLIST_HEAD(&tun->flows[i]);
1353
1354         tun->ageing_time = TUN_FLOW_EXPIRE;
1355         timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1356         mod_timer(&tun->flow_gc_timer,
1357                   round_jiffies_up(jiffies + tun->ageing_time));
1358 }
1359
1360 static void tun_flow_uninit(struct tun_struct *tun)
1361 {
1362         del_timer_sync(&tun->flow_gc_timer);
1363         tun_flow_flush(tun);
1364 }
1365
1366 #define MIN_MTU 68
1367 #define MAX_MTU 65535
1368
1369 /* Initialize net device. */
1370 static void tun_net_initialize(struct net_device *dev)
1371 {
1372         struct tun_struct *tun = netdev_priv(dev);
1373
1374         switch (tun->flags & TUN_TYPE_MASK) {
1375         case IFF_TUN:
1376                 dev->netdev_ops = &tun_netdev_ops;
1377                 dev->header_ops = &ip_tunnel_header_ops;
1378
1379                 /* Point-to-Point TUN Device */
1380                 dev->hard_header_len = 0;
1381                 dev->addr_len = 0;
1382                 dev->mtu = 1500;
1383
1384                 /* Zero header length */
1385                 dev->type = ARPHRD_NONE;
1386                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1387                 break;
1388
1389         case IFF_TAP:
1390                 dev->netdev_ops = &tap_netdev_ops;
1391                 /* Ethernet TAP Device */
1392                 ether_setup(dev);
1393                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1394                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1395
1396                 eth_hw_addr_random(dev);
1397
1398                 /* Currently tun does not support XDP, only tap does. */
1399                 dev->xdp_features = NETDEV_XDP_ACT_BASIC |
1400                                     NETDEV_XDP_ACT_REDIRECT |
1401                                     NETDEV_XDP_ACT_NDO_XMIT;
1402
1403                 break;
1404         }
1405
1406         dev->min_mtu = MIN_MTU;
1407         dev->max_mtu = MAX_MTU - dev->hard_header_len;
1408 }
1409
1410 static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1411 {
1412         struct sock *sk = tfile->socket.sk;
1413
1414         return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1415 }
1416
1417 /* Character device part */
1418
1419 /* Poll */
1420 static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1421 {
1422         struct tun_file *tfile = file->private_data;
1423         struct tun_struct *tun = tun_get(tfile);
1424         struct sock *sk;
1425         __poll_t mask = 0;
1426
1427         if (!tun)
1428                 return EPOLLERR;
1429
1430         sk = tfile->socket.sk;
1431
1432         poll_wait(file, sk_sleep(sk), wait);
1433
1434         if (!ptr_ring_empty(&tfile->tx_ring))
1435                 mask |= EPOLLIN | EPOLLRDNORM;
1436
1437         /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1438          * guarantee EPOLLOUT to be raised by either here or
1439          * tun_sock_write_space(). Then process could get notification
1440          * after it writes to a down device and meets -EIO.
1441          */
1442         if (tun_sock_writeable(tun, tfile) ||
1443             (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1444              tun_sock_writeable(tun, tfile)))
1445                 mask |= EPOLLOUT | EPOLLWRNORM;
1446
1447         if (tun->dev->reg_state != NETREG_REGISTERED)
1448                 mask = EPOLLERR;
1449
1450         tun_put(tun);
1451         return mask;
1452 }
1453
1454 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1455                                             size_t len,
1456                                             const struct iov_iter *it)
1457 {
1458         struct sk_buff *skb;
1459         size_t linear;
1460         int err;
1461         int i;
1462
1463         if (it->nr_segs > MAX_SKB_FRAGS + 1 ||
1464             len > (ETH_MAX_MTU - NET_SKB_PAD - NET_IP_ALIGN))
1465                 return ERR_PTR(-EMSGSIZE);
1466
1467         local_bh_disable();
1468         skb = napi_get_frags(&tfile->napi);
1469         local_bh_enable();
1470         if (!skb)
1471                 return ERR_PTR(-ENOMEM);
1472
1473         linear = iov_iter_single_seg_count(it);
1474         err = __skb_grow(skb, linear);
1475         if (err)
1476                 goto free;
1477
1478         skb->len = len;
1479         skb->data_len = len - linear;
1480         skb->truesize += skb->data_len;
1481
1482         for (i = 1; i < it->nr_segs; i++) {
1483                 const struct iovec *iov = iter_iov(it);
1484                 size_t fragsz = iov->iov_len;
1485                 struct page *page;
1486                 void *frag;
1487
1488                 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1489                         err = -EINVAL;
1490                         goto free;
1491                 }
1492                 frag = netdev_alloc_frag(fragsz);
1493                 if (!frag) {
1494                         err = -ENOMEM;
1495                         goto free;
1496                 }
1497                 page = virt_to_head_page(frag);
1498                 skb_fill_page_desc(skb, i - 1, page,
1499                                    frag - page_address(page), fragsz);
1500         }
1501
1502         return skb;
1503 free:
1504         /* frees skb and all frags allocated with napi_alloc_frag() */
1505         napi_free_frags(&tfile->napi);
1506         return ERR_PTR(err);
1507 }
1508
1509 /* prepad is the amount to reserve at front.  len is length after that.
1510  * linear is a hint as to how much to copy (usually headers). */
1511 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1512                                      size_t prepad, size_t len,
1513                                      size_t linear, int noblock)
1514 {
1515         struct sock *sk = tfile->socket.sk;
1516         struct sk_buff *skb;
1517         int err;
1518
1519         /* Under a page?  Don't bother with paged skb. */
1520         if (prepad + len < PAGE_SIZE)
1521                 linear = len;
1522
1523         if (len - linear > MAX_SKB_FRAGS * (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
1524                 linear = len - MAX_SKB_FRAGS * (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER);
1525         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1526                                    &err, PAGE_ALLOC_COSTLY_ORDER);
1527         if (!skb)
1528                 return ERR_PTR(err);
1529
1530         skb_reserve(skb, prepad);
1531         skb_put(skb, linear);
1532         skb->data_len = len - linear;
1533         skb->len += len - linear;
1534
1535         return skb;
1536 }
1537
1538 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1539                            struct sk_buff *skb, int more)
1540 {
1541         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1542         struct sk_buff_head process_queue;
1543         u32 rx_batched = tun->rx_batched;
1544         bool rcv = false;
1545
1546         if (!rx_batched || (!more && skb_queue_empty(queue))) {
1547                 local_bh_disable();
1548                 skb_record_rx_queue(skb, tfile->queue_index);
1549                 netif_receive_skb(skb);
1550                 local_bh_enable();
1551                 return;
1552         }
1553
1554         spin_lock(&queue->lock);
1555         if (!more || skb_queue_len(queue) == rx_batched) {
1556                 __skb_queue_head_init(&process_queue);
1557                 skb_queue_splice_tail_init(queue, &process_queue);
1558                 rcv = true;
1559         } else {
1560                 __skb_queue_tail(queue, skb);
1561         }
1562         spin_unlock(&queue->lock);
1563
1564         if (rcv) {
1565                 struct sk_buff *nskb;
1566
1567                 local_bh_disable();
1568                 while ((nskb = __skb_dequeue(&process_queue))) {
1569                         skb_record_rx_queue(nskb, tfile->queue_index);
1570                         netif_receive_skb(nskb);
1571                 }
1572                 skb_record_rx_queue(skb, tfile->queue_index);
1573                 netif_receive_skb(skb);
1574                 local_bh_enable();
1575         }
1576 }
1577
1578 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1579                               int len, int noblock, bool zerocopy)
1580 {
1581         if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1582                 return false;
1583
1584         if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1585                 return false;
1586
1587         if (!noblock)
1588                 return false;
1589
1590         if (zerocopy)
1591                 return false;
1592
1593         if (SKB_DATA_ALIGN(len + TUN_RX_PAD + XDP_PACKET_HEADROOM) +
1594             SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1595                 return false;
1596
1597         return true;
1598 }
1599
1600 static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
1601                                        struct page_frag *alloc_frag, char *buf,
1602                                        int buflen, int len, int pad)
1603 {
1604         struct sk_buff *skb = build_skb(buf, buflen);
1605
1606         if (!skb)
1607                 return ERR_PTR(-ENOMEM);
1608
1609         skb_reserve(skb, pad);
1610         skb_put(skb, len);
1611         skb_set_owner_w(skb, tfile->socket.sk);
1612
1613         get_page(alloc_frag->page);
1614         alloc_frag->offset += buflen;
1615
1616         return skb;
1617 }
1618
1619 static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1620                        struct xdp_buff *xdp, u32 act)
1621 {
1622         int err;
1623
1624         switch (act) {
1625         case XDP_REDIRECT:
1626                 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1627                 if (err) {
1628                         dev_core_stats_rx_dropped_inc(tun->dev);
1629                         return err;
1630                 }
1631                 dev_sw_netstats_rx_add(tun->dev, xdp->data_end - xdp->data);
1632                 break;
1633         case XDP_TX:
1634                 err = tun_xdp_tx(tun->dev, xdp);
1635                 if (err < 0) {
1636                         dev_core_stats_rx_dropped_inc(tun->dev);
1637                         return err;
1638                 }
1639                 dev_sw_netstats_rx_add(tun->dev, xdp->data_end - xdp->data);
1640                 break;
1641         case XDP_PASS:
1642                 break;
1643         default:
1644                 bpf_warn_invalid_xdp_action(tun->dev, xdp_prog, act);
1645                 fallthrough;
1646         case XDP_ABORTED:
1647                 trace_xdp_exception(tun->dev, xdp_prog, act);
1648                 fallthrough;
1649         case XDP_DROP:
1650                 dev_core_stats_rx_dropped_inc(tun->dev);
1651                 break;
1652         }
1653
1654         return act;
1655 }
1656
1657 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1658                                      struct tun_file *tfile,
1659                                      struct iov_iter *from,
1660                                      struct virtio_net_hdr *hdr,
1661                                      int len, int *skb_xdp)
1662 {
1663         struct page_frag *alloc_frag = &current->task_frag;
1664         struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
1665         struct bpf_prog *xdp_prog;
1666         int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1667         char *buf;
1668         size_t copied;
1669         int pad = TUN_RX_PAD;
1670         int err = 0;
1671
1672         rcu_read_lock();
1673         xdp_prog = rcu_dereference(tun->xdp_prog);
1674         if (xdp_prog)
1675                 pad += XDP_PACKET_HEADROOM;
1676         buflen += SKB_DATA_ALIGN(len + pad);
1677         rcu_read_unlock();
1678
1679         alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1680         if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1681                 return ERR_PTR(-ENOMEM);
1682
1683         buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1684         copied = copy_page_from_iter(alloc_frag->page,
1685                                      alloc_frag->offset + pad,
1686                                      len, from);
1687         if (copied != len)
1688                 return ERR_PTR(-EFAULT);
1689
1690         /* There's a small window that XDP may be set after the check
1691          * of xdp_prog above, this should be rare and for simplicity
1692          * we do XDP on skb in case the headroom is not enough.
1693          */
1694         if (hdr->gso_type || !xdp_prog) {
1695                 *skb_xdp = 1;
1696                 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len,
1697                                        pad);
1698         }
1699
1700         *skb_xdp = 0;
1701
1702         local_bh_disable();
1703         rcu_read_lock();
1704         bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
1705         xdp_prog = rcu_dereference(tun->xdp_prog);
1706         if (xdp_prog) {
1707                 struct xdp_buff xdp;
1708                 u32 act;
1709
1710                 xdp_init_buff(&xdp, buflen, &tfile->xdp_rxq);
1711                 xdp_prepare_buff(&xdp, buf, pad, len, false);
1712
1713                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1714                 if (act == XDP_REDIRECT || act == XDP_TX) {
1715                         get_page(alloc_frag->page);
1716                         alloc_frag->offset += buflen;
1717                 }
1718                 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1719                 if (err < 0) {
1720                         if (act == XDP_REDIRECT || act == XDP_TX)
1721                                 put_page(alloc_frag->page);
1722                         goto out;
1723                 }
1724
1725                 if (err == XDP_REDIRECT)
1726                         xdp_do_flush();
1727                 if (err != XDP_PASS)
1728                         goto out;
1729
1730                 pad = xdp.data - xdp.data_hard_start;
1731                 len = xdp.data_end - xdp.data;
1732         }
1733         bpf_net_ctx_clear(bpf_net_ctx);
1734         rcu_read_unlock();
1735         local_bh_enable();
1736
1737         return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1738
1739 out:
1740         bpf_net_ctx_clear(bpf_net_ctx);
1741         rcu_read_unlock();
1742         local_bh_enable();
1743         return NULL;
1744 }
1745
1746 /* Get packet from user space buffer */
1747 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1748                             void *msg_control, struct iov_iter *from,
1749                             int noblock, bool more)
1750 {
1751         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1752         struct sk_buff *skb;
1753         size_t total_len = iov_iter_count(from);
1754         size_t len = total_len, align = tun->align, linear;
1755         struct virtio_net_hdr gso = { 0 };
1756         int good_linear;
1757         int copylen;
1758         bool zerocopy = false;
1759         int err;
1760         u32 rxhash = 0;
1761         int skb_xdp = 1;
1762         bool frags = tun_napi_frags_enabled(tfile);
1763         enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
1764
1765         if (!(tun->flags & IFF_NO_PI)) {
1766                 if (len < sizeof(pi))
1767                         return -EINVAL;
1768                 len -= sizeof(pi);
1769
1770                 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1771                         return -EFAULT;
1772         }
1773
1774         if (tun->flags & IFF_VNET_HDR) {
1775                 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1776
1777                 if (len < vnet_hdr_sz)
1778                         return -EINVAL;
1779                 len -= vnet_hdr_sz;
1780
1781                 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1782                         return -EFAULT;
1783
1784                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1785                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1786                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1787
1788                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1789                         return -EINVAL;
1790                 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1791         }
1792
1793         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1794                 align += NET_IP_ALIGN;
1795                 if (unlikely(len < ETH_HLEN ||
1796                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1797                         return -EINVAL;
1798         }
1799
1800         good_linear = SKB_MAX_HEAD(align);
1801
1802         if (msg_control) {
1803                 struct iov_iter i = *from;
1804
1805                 /* There are 256 bytes to be copied in skb, so there is
1806                  * enough room for skb expand head in case it is used.
1807                  * The rest of the buffer is mapped from userspace.
1808                  */
1809                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1810                 if (copylen > good_linear)
1811                         copylen = good_linear;
1812                 linear = copylen;
1813                 iov_iter_advance(&i, copylen);
1814                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1815                         zerocopy = true;
1816         }
1817
1818         if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1819                 /* For the packet that is not easy to be processed
1820                  * (e.g gso or jumbo packet), we will do it at after
1821                  * skb was created with generic XDP routine.
1822                  */
1823                 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1824                 err = PTR_ERR_OR_ZERO(skb);
1825                 if (err)
1826                         goto drop;
1827                 if (!skb)
1828                         return total_len;
1829         } else {
1830                 if (!zerocopy) {
1831                         copylen = len;
1832                         if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1833                                 linear = good_linear;
1834                         else
1835                                 linear = tun16_to_cpu(tun, gso.hdr_len);
1836                 }
1837
1838                 if (frags) {
1839                         mutex_lock(&tfile->napi_mutex);
1840                         skb = tun_napi_alloc_frags(tfile, copylen, from);
1841                         /* tun_napi_alloc_frags() enforces a layout for the skb.
1842                          * If zerocopy is enabled, then this layout will be
1843                          * overwritten by zerocopy_sg_from_iter().
1844                          */
1845                         zerocopy = false;
1846                 } else {
1847                         if (!linear)
1848                                 linear = min_t(size_t, good_linear, copylen);
1849
1850                         skb = tun_alloc_skb(tfile, align, copylen, linear,
1851                                             noblock);
1852                 }
1853
1854                 err = PTR_ERR_OR_ZERO(skb);
1855                 if (err)
1856                         goto drop;
1857
1858                 if (zerocopy)
1859                         err = zerocopy_sg_from_iter(skb, from);
1860                 else
1861                         err = skb_copy_datagram_from_iter(skb, 0, from, len);
1862
1863                 if (err) {
1864                         err = -EFAULT;
1865                         drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
1866                         goto drop;
1867                 }
1868         }
1869
1870         if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1871                 atomic_long_inc(&tun->rx_frame_errors);
1872                 err = -EINVAL;
1873                 goto free_skb;
1874         }
1875
1876         switch (tun->flags & TUN_TYPE_MASK) {
1877         case IFF_TUN:
1878                 if (tun->flags & IFF_NO_PI) {
1879                         u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1880
1881                         switch (ip_version) {
1882                         case 4:
1883                                 pi.proto = htons(ETH_P_IP);
1884                                 break;
1885                         case 6:
1886                                 pi.proto = htons(ETH_P_IPV6);
1887                                 break;
1888                         default:
1889                                 err = -EINVAL;
1890                                 goto drop;
1891                         }
1892                 }
1893
1894                 skb_reset_mac_header(skb);
1895                 skb->protocol = pi.proto;
1896                 skb->dev = tun->dev;
1897                 break;
1898         case IFF_TAP:
1899                 if (frags && !pskb_may_pull(skb, ETH_HLEN)) {
1900                         err = -ENOMEM;
1901                         drop_reason = SKB_DROP_REASON_HDR_TRUNC;
1902                         goto drop;
1903                 }
1904                 skb->protocol = eth_type_trans(skb, tun->dev);
1905                 break;
1906         }
1907
1908         /* copy skb_ubuf_info for callback when skb has no error */
1909         if (zerocopy) {
1910                 skb_zcopy_init(skb, msg_control);
1911         } else if (msg_control) {
1912                 struct ubuf_info *uarg = msg_control;
1913                 uarg->ops->complete(NULL, uarg, false);
1914         }
1915
1916         skb_reset_network_header(skb);
1917         skb_probe_transport_header(skb);
1918         skb_record_rx_queue(skb, tfile->queue_index);
1919
1920         if (skb_xdp) {
1921                 struct bpf_prog *xdp_prog;
1922                 int ret;
1923
1924                 local_bh_disable();
1925                 rcu_read_lock();
1926                 xdp_prog = rcu_dereference(tun->xdp_prog);
1927                 if (xdp_prog) {
1928                         ret = do_xdp_generic(xdp_prog, &skb);
1929                         if (ret != XDP_PASS) {
1930                                 rcu_read_unlock();
1931                                 local_bh_enable();
1932                                 goto unlock_frags;
1933                         }
1934                 }
1935                 rcu_read_unlock();
1936                 local_bh_enable();
1937         }
1938
1939         /* Compute the costly rx hash only if needed for flow updates.
1940          * We may get a very small possibility of OOO during switching, not
1941          * worth to optimize.
1942          */
1943         if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1944             !tfile->detached)
1945                 rxhash = __skb_get_hash_symmetric(skb);
1946
1947         rcu_read_lock();
1948         if (unlikely(!(tun->dev->flags & IFF_UP))) {
1949                 err = -EIO;
1950                 rcu_read_unlock();
1951                 drop_reason = SKB_DROP_REASON_DEV_READY;
1952                 goto drop;
1953         }
1954
1955         if (frags) {
1956                 u32 headlen;
1957
1958                 /* Exercise flow dissector code path. */
1959                 skb_push(skb, ETH_HLEN);
1960                 headlen = eth_get_headlen(tun->dev, skb->data,
1961                                           skb_headlen(skb));
1962
1963                 if (unlikely(headlen > skb_headlen(skb))) {
1964                         WARN_ON_ONCE(1);
1965                         err = -ENOMEM;
1966                         dev_core_stats_rx_dropped_inc(tun->dev);
1967 napi_busy:
1968                         napi_free_frags(&tfile->napi);
1969                         rcu_read_unlock();
1970                         mutex_unlock(&tfile->napi_mutex);
1971                         return err;
1972                 }
1973
1974                 if (likely(napi_schedule_prep(&tfile->napi))) {
1975                         local_bh_disable();
1976                         napi_gro_frags(&tfile->napi);
1977                         napi_complete(&tfile->napi);
1978                         local_bh_enable();
1979                 } else {
1980                         err = -EBUSY;
1981                         goto napi_busy;
1982                 }
1983                 mutex_unlock(&tfile->napi_mutex);
1984         } else if (tfile->napi_enabled) {
1985                 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1986                 int queue_len;
1987
1988                 spin_lock_bh(&queue->lock);
1989
1990                 if (unlikely(tfile->detached)) {
1991                         spin_unlock_bh(&queue->lock);
1992                         rcu_read_unlock();
1993                         err = -EBUSY;
1994                         goto free_skb;
1995                 }
1996
1997                 __skb_queue_tail(queue, skb);
1998                 queue_len = skb_queue_len(queue);
1999                 spin_unlock(&queue->lock);
2000
2001                 if (!more || queue_len > NAPI_POLL_WEIGHT)
2002                         napi_schedule(&tfile->napi);
2003
2004                 local_bh_enable();
2005         } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
2006                 tun_rx_batched(tun, tfile, skb, more);
2007         } else {
2008                 netif_rx(skb);
2009         }
2010         rcu_read_unlock();
2011
2012         preempt_disable();
2013         dev_sw_netstats_rx_add(tun->dev, len);
2014         preempt_enable();
2015
2016         if (rxhash)
2017                 tun_flow_update(tun, rxhash, tfile);
2018
2019         return total_len;
2020
2021 drop:
2022         if (err != -EAGAIN)
2023                 dev_core_stats_rx_dropped_inc(tun->dev);
2024
2025 free_skb:
2026         if (!IS_ERR_OR_NULL(skb))
2027                 kfree_skb_reason(skb, drop_reason);
2028
2029 unlock_frags:
2030         if (frags) {
2031                 tfile->napi.skb = NULL;
2032                 mutex_unlock(&tfile->napi_mutex);
2033         }
2034
2035         return err ?: total_len;
2036 }
2037
2038 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
2039 {
2040         struct file *file = iocb->ki_filp;
2041         struct tun_file *tfile = file->private_data;
2042         struct tun_struct *tun = tun_get(tfile);
2043         ssize_t result;
2044         int noblock = 0;
2045
2046         if (!tun)
2047                 return -EBADFD;
2048
2049         if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
2050                 noblock = 1;
2051
2052         result = tun_get_user(tun, tfile, NULL, from, noblock, false);
2053
2054         tun_put(tun);
2055         return result;
2056 }
2057
2058 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2059                                 struct tun_file *tfile,
2060                                 struct xdp_frame *xdp_frame,
2061                                 struct iov_iter *iter)
2062 {
2063         int vnet_hdr_sz = 0;
2064         size_t size = xdp_frame->len;
2065         size_t ret;
2066
2067         if (tun->flags & IFF_VNET_HDR) {
2068                 struct virtio_net_hdr gso = { 0 };
2069
2070                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2071                 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2072                         return -EINVAL;
2073                 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2074                              sizeof(gso)))
2075                         return -EFAULT;
2076                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2077         }
2078
2079         ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2080
2081         preempt_disable();
2082         dev_sw_netstats_tx_add(tun->dev, 1, ret);
2083         preempt_enable();
2084
2085         return ret;
2086 }
2087
2088 /* Put packet to the user space buffer */
2089 static ssize_t tun_put_user(struct tun_struct *tun,
2090                             struct tun_file *tfile,
2091                             struct sk_buff *skb,
2092                             struct iov_iter *iter)
2093 {
2094         struct tun_pi pi = { 0, skb->protocol };
2095         ssize_t total;
2096         int vlan_offset = 0;
2097         int vlan_hlen = 0;
2098         int vnet_hdr_sz = 0;
2099
2100         if (skb_vlan_tag_present(skb))
2101                 vlan_hlen = VLAN_HLEN;
2102
2103         if (tun->flags & IFF_VNET_HDR)
2104                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2105
2106         total = skb->len + vlan_hlen + vnet_hdr_sz;
2107
2108         if (!(tun->flags & IFF_NO_PI)) {
2109                 if (iov_iter_count(iter) < sizeof(pi))
2110                         return -EINVAL;
2111
2112                 total += sizeof(pi);
2113                 if (iov_iter_count(iter) < total) {
2114                         /* Packet will be striped */
2115                         pi.flags |= TUN_PKT_STRIP;
2116                 }
2117
2118                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2119                         return -EFAULT;
2120         }
2121
2122         if (vnet_hdr_sz) {
2123                 struct virtio_net_hdr gso;
2124
2125                 if (iov_iter_count(iter) < vnet_hdr_sz)
2126                         return -EINVAL;
2127
2128                 if (virtio_net_hdr_from_skb(skb, &gso,
2129                                             tun_is_little_endian(tun), true,
2130                                             vlan_hlen)) {
2131                         struct skb_shared_info *sinfo = skb_shinfo(skb);
2132
2133                         if (net_ratelimit()) {
2134                                 netdev_err(tun->dev, "unexpected GSO type: 0x%x, gso_size %d, hdr_len %d\n",
2135                                            sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2136                                            tun16_to_cpu(tun, gso.hdr_len));
2137                                 print_hex_dump(KERN_ERR, "tun: ",
2138                                                DUMP_PREFIX_NONE,
2139                                                16, 1, skb->head,
2140                                                min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2141                         }
2142                         WARN_ON_ONCE(1);
2143                         return -EINVAL;
2144                 }
2145
2146                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2147                         return -EFAULT;
2148
2149                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2150         }
2151
2152         if (vlan_hlen) {
2153                 int ret;
2154                 struct veth veth;
2155
2156                 veth.h_vlan_proto = skb->vlan_proto;
2157                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2158
2159                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2160
2161                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2162                 if (ret || !iov_iter_count(iter))
2163                         goto done;
2164
2165                 ret = copy_to_iter(&veth, sizeof(veth), iter);
2166                 if (ret != sizeof(veth) || !iov_iter_count(iter))
2167                         goto done;
2168         }
2169
2170         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2171
2172 done:
2173         /* caller is in process context, */
2174         preempt_disable();
2175         dev_sw_netstats_tx_add(tun->dev, 1, skb->len + vlan_hlen);
2176         preempt_enable();
2177
2178         return total;
2179 }
2180
2181 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2182 {
2183         DECLARE_WAITQUEUE(wait, current);
2184         void *ptr = NULL;
2185         int error = 0;
2186
2187         ptr = ptr_ring_consume(&tfile->tx_ring);
2188         if (ptr)
2189                 goto out;
2190         if (noblock) {
2191                 error = -EAGAIN;
2192                 goto out;
2193         }
2194
2195         add_wait_queue(&tfile->socket.wq.wait, &wait);
2196
2197         while (1) {
2198                 set_current_state(TASK_INTERRUPTIBLE);
2199                 ptr = ptr_ring_consume(&tfile->tx_ring);
2200                 if (ptr)
2201                         break;
2202                 if (signal_pending(current)) {
2203                         error = -ERESTARTSYS;
2204                         break;
2205                 }
2206                 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2207                         error = -EFAULT;
2208                         break;
2209                 }
2210
2211                 schedule();
2212         }
2213
2214         __set_current_state(TASK_RUNNING);
2215         remove_wait_queue(&tfile->socket.wq.wait, &wait);
2216
2217 out:
2218         *err = error;
2219         return ptr;
2220 }
2221
2222 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2223                            struct iov_iter *to,
2224                            int noblock, void *ptr)
2225 {
2226         ssize_t ret;
2227         int err;
2228
2229         if (!iov_iter_count(to)) {
2230                 tun_ptr_free(ptr);
2231                 return 0;
2232         }
2233
2234         if (!ptr) {
2235                 /* Read frames from ring */
2236                 ptr = tun_ring_recv(tfile, noblock, &err);
2237                 if (!ptr)
2238                         return err;
2239         }
2240
2241         if (tun_is_xdp_frame(ptr)) {
2242                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2243
2244                 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2245                 xdp_return_frame(xdpf);
2246         } else {
2247                 struct sk_buff *skb = ptr;
2248
2249                 ret = tun_put_user(tun, tfile, skb, to);
2250                 if (unlikely(ret < 0))
2251                         kfree_skb(skb);
2252                 else
2253                         consume_skb(skb);
2254         }
2255
2256         return ret;
2257 }
2258
2259 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2260 {
2261         struct file *file = iocb->ki_filp;
2262         struct tun_file *tfile = file->private_data;
2263         struct tun_struct *tun = tun_get(tfile);
2264         ssize_t len = iov_iter_count(to), ret;
2265         int noblock = 0;
2266
2267         if (!tun)
2268                 return -EBADFD;
2269
2270         if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
2271                 noblock = 1;
2272
2273         ret = tun_do_read(tun, tfile, to, noblock, NULL);
2274         ret = min_t(ssize_t, ret, len);
2275         if (ret > 0)
2276                 iocb->ki_pos = ret;
2277         tun_put(tun);
2278         return ret;
2279 }
2280
2281 static void tun_prog_free(struct rcu_head *rcu)
2282 {
2283         struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2284
2285         bpf_prog_destroy(prog->prog);
2286         kfree(prog);
2287 }
2288
2289 static int __tun_set_ebpf(struct tun_struct *tun,
2290                           struct tun_prog __rcu **prog_p,
2291                           struct bpf_prog *prog)
2292 {
2293         struct tun_prog *old, *new = NULL;
2294
2295         if (prog) {
2296                 new = kmalloc(sizeof(*new), GFP_KERNEL);
2297                 if (!new)
2298                         return -ENOMEM;
2299                 new->prog = prog;
2300         }
2301
2302         spin_lock_bh(&tun->lock);
2303         old = rcu_dereference_protected(*prog_p,
2304                                         lockdep_is_held(&tun->lock));
2305         rcu_assign_pointer(*prog_p, new);
2306         spin_unlock_bh(&tun->lock);
2307
2308         if (old)
2309                 call_rcu(&old->rcu, tun_prog_free);
2310
2311         return 0;
2312 }
2313
2314 static void tun_free_netdev(struct net_device *dev)
2315 {
2316         struct tun_struct *tun = netdev_priv(dev);
2317
2318         BUG_ON(!(list_empty(&tun->disabled)));
2319
2320         tun_flow_uninit(tun);
2321         security_tun_dev_free_security(tun->security);
2322         __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2323         __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2324 }
2325
2326 static void tun_setup(struct net_device *dev)
2327 {
2328         struct tun_struct *tun = netdev_priv(dev);
2329
2330         tun->owner = INVALID_UID;
2331         tun->group = INVALID_GID;
2332         tun_default_link_ksettings(dev, &tun->link_ksettings);
2333
2334         dev->ethtool_ops = &tun_ethtool_ops;
2335         dev->needs_free_netdev = true;
2336         dev->priv_destructor = tun_free_netdev;
2337         /* We prefer our own queue length */
2338         dev->tx_queue_len = TUN_READQ_SIZE;
2339 }
2340
2341 /* Trivial set of netlink ops to allow deleting tun or tap
2342  * device with netlink.
2343  */
2344 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2345                         struct netlink_ext_ack *extack)
2346 {
2347         NL_SET_ERR_MSG(extack,
2348                        "tun/tap creation via rtnetlink is not supported.");
2349         return -EOPNOTSUPP;
2350 }
2351
2352 static size_t tun_get_size(const struct net_device *dev)
2353 {
2354         BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2355         BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2356
2357         return nla_total_size(sizeof(uid_t)) + /* OWNER */
2358                nla_total_size(sizeof(gid_t)) + /* GROUP */
2359                nla_total_size(sizeof(u8)) + /* TYPE */
2360                nla_total_size(sizeof(u8)) + /* PI */
2361                nla_total_size(sizeof(u8)) + /* VNET_HDR */
2362                nla_total_size(sizeof(u8)) + /* PERSIST */
2363                nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2364                nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2365                nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2366                0;
2367 }
2368
2369 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2370 {
2371         struct tun_struct *tun = netdev_priv(dev);
2372
2373         if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2374                 goto nla_put_failure;
2375         if (uid_valid(tun->owner) &&
2376             nla_put_u32(skb, IFLA_TUN_OWNER,
2377                         from_kuid_munged(current_user_ns(), tun->owner)))
2378                 goto nla_put_failure;
2379         if (gid_valid(tun->group) &&
2380             nla_put_u32(skb, IFLA_TUN_GROUP,
2381                         from_kgid_munged(current_user_ns(), tun->group)))
2382                 goto nla_put_failure;
2383         if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2384                 goto nla_put_failure;
2385         if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2386                 goto nla_put_failure;
2387         if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2388                 goto nla_put_failure;
2389         if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2390                        !!(tun->flags & IFF_MULTI_QUEUE)))
2391                 goto nla_put_failure;
2392         if (tun->flags & IFF_MULTI_QUEUE) {
2393                 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2394                         goto nla_put_failure;
2395                 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2396                                 tun->numdisabled))
2397                         goto nla_put_failure;
2398         }
2399
2400         return 0;
2401
2402 nla_put_failure:
2403         return -EMSGSIZE;
2404 }
2405
2406 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2407         .kind           = DRV_NAME,
2408         .priv_size      = sizeof(struct tun_struct),
2409         .setup          = tun_setup,
2410         .validate       = tun_validate,
2411         .get_size       = tun_get_size,
2412         .fill_info      = tun_fill_info,
2413 };
2414
2415 static void tun_sock_write_space(struct sock *sk)
2416 {
2417         struct tun_file *tfile;
2418         wait_queue_head_t *wqueue;
2419
2420         if (!sock_writeable(sk))
2421                 return;
2422
2423         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2424                 return;
2425
2426         wqueue = sk_sleep(sk);
2427         if (wqueue && waitqueue_active(wqueue))
2428                 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2429                                                 EPOLLWRNORM | EPOLLWRBAND);
2430
2431         tfile = container_of(sk, struct tun_file, sk);
2432         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2433 }
2434
2435 static void tun_put_page(struct tun_page *tpage)
2436 {
2437         if (tpage->page)
2438                 __page_frag_cache_drain(tpage->page, tpage->count);
2439 }
2440
2441 static int tun_xdp_one(struct tun_struct *tun,
2442                        struct tun_file *tfile,
2443                        struct xdp_buff *xdp, int *flush,
2444                        struct tun_page *tpage)
2445 {
2446         unsigned int datasize = xdp->data_end - xdp->data;
2447         struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2448         struct virtio_net_hdr *gso = &hdr->gso;
2449         struct bpf_prog *xdp_prog;
2450         struct sk_buff *skb = NULL;
2451         struct sk_buff_head *queue;
2452         u32 rxhash = 0, act;
2453         int buflen = hdr->buflen;
2454         int ret = 0;
2455         bool skb_xdp = false;
2456         struct page *page;
2457
2458         if (unlikely(datasize < ETH_HLEN))
2459                 return -EINVAL;
2460
2461         xdp_prog = rcu_dereference(tun->xdp_prog);
2462         if (xdp_prog) {
2463                 if (gso->gso_type) {
2464                         skb_xdp = true;
2465                         goto build;
2466                 }
2467
2468                 xdp_init_buff(xdp, buflen, &tfile->xdp_rxq);
2469                 xdp_set_data_meta_invalid(xdp);
2470
2471                 act = bpf_prog_run_xdp(xdp_prog, xdp);
2472                 ret = tun_xdp_act(tun, xdp_prog, xdp, act);
2473                 if (ret < 0) {
2474                         put_page(virt_to_head_page(xdp->data));
2475                         return ret;
2476                 }
2477
2478                 switch (ret) {
2479                 case XDP_REDIRECT:
2480                         *flush = true;
2481                         fallthrough;
2482                 case XDP_TX:
2483                         return 0;
2484                 case XDP_PASS:
2485                         break;
2486                 default:
2487                         page = virt_to_head_page(xdp->data);
2488                         if (tpage->page == page) {
2489                                 ++tpage->count;
2490                         } else {
2491                                 tun_put_page(tpage);
2492                                 tpage->page = page;
2493                                 tpage->count = 1;
2494                         }
2495                         return 0;
2496                 }
2497         }
2498
2499 build:
2500         skb = build_skb(xdp->data_hard_start, buflen);
2501         if (!skb) {
2502                 ret = -ENOMEM;
2503                 goto out;
2504         }
2505
2506         skb_reserve(skb, xdp->data - xdp->data_hard_start);
2507         skb_put(skb, xdp->data_end - xdp->data);
2508
2509         if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2510                 atomic_long_inc(&tun->rx_frame_errors);
2511                 kfree_skb(skb);
2512                 ret = -EINVAL;
2513                 goto out;
2514         }
2515
2516         skb->protocol = eth_type_trans(skb, tun->dev);
2517         skb_reset_network_header(skb);
2518         skb_probe_transport_header(skb);
2519         skb_record_rx_queue(skb, tfile->queue_index);
2520
2521         if (skb_xdp) {
2522                 ret = do_xdp_generic(xdp_prog, &skb);
2523                 if (ret != XDP_PASS) {
2524                         ret = 0;
2525                         goto out;
2526                 }
2527         }
2528
2529         if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2530             !tfile->detached)
2531                 rxhash = __skb_get_hash_symmetric(skb);
2532
2533         if (tfile->napi_enabled) {
2534                 queue = &tfile->sk.sk_write_queue;
2535                 spin_lock(&queue->lock);
2536
2537                 if (unlikely(tfile->detached)) {
2538                         spin_unlock(&queue->lock);
2539                         kfree_skb(skb);
2540                         return -EBUSY;
2541                 }
2542
2543                 __skb_queue_tail(queue, skb);
2544                 spin_unlock(&queue->lock);
2545                 ret = 1;
2546         } else {
2547                 netif_receive_skb(skb);
2548                 ret = 0;
2549         }
2550
2551         /* No need to disable preemption here since this function is
2552          * always called with bh disabled
2553          */
2554         dev_sw_netstats_rx_add(tun->dev, datasize);
2555
2556         if (rxhash)
2557                 tun_flow_update(tun, rxhash, tfile);
2558
2559 out:
2560         return ret;
2561 }
2562
2563 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2564 {
2565         int ret, i;
2566         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2567         struct tun_struct *tun = tun_get(tfile);
2568         struct tun_msg_ctl *ctl = m->msg_control;
2569         struct xdp_buff *xdp;
2570
2571         if (!tun)
2572                 return -EBADFD;
2573
2574         if (m->msg_controllen == sizeof(struct tun_msg_ctl) &&
2575             ctl && ctl->type == TUN_MSG_PTR) {
2576                 struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
2577                 struct tun_page tpage;
2578                 int n = ctl->num;
2579                 int flush = 0, queued = 0;
2580
2581                 memset(&tpage, 0, sizeof(tpage));
2582
2583                 local_bh_disable();
2584                 rcu_read_lock();
2585                 bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
2586
2587                 for (i = 0; i < n; i++) {
2588                         xdp = &((struct xdp_buff *)ctl->ptr)[i];
2589                         ret = tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2590                         if (ret > 0)
2591                                 queued += ret;
2592                 }
2593
2594                 if (flush)
2595                         xdp_do_flush();
2596
2597                 if (tfile->napi_enabled && queued > 0)
2598                         napi_schedule(&tfile->napi);
2599
2600                 bpf_net_ctx_clear(bpf_net_ctx);
2601                 rcu_read_unlock();
2602                 local_bh_enable();
2603
2604                 tun_put_page(&tpage);
2605
2606                 ret = total_len;
2607                 goto out;
2608         }
2609
2610         ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2611                            m->msg_flags & MSG_DONTWAIT,
2612                            m->msg_flags & MSG_MORE);
2613 out:
2614         tun_put(tun);
2615         return ret;
2616 }
2617
2618 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2619                        int flags)
2620 {
2621         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2622         struct tun_struct *tun = tun_get(tfile);
2623         void *ptr = m->msg_control;
2624         int ret;
2625
2626         if (!tun) {
2627                 ret = -EBADFD;
2628                 goto out_free;
2629         }
2630
2631         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2632                 ret = -EINVAL;
2633                 goto out_put_tun;
2634         }
2635         if (flags & MSG_ERRQUEUE) {
2636                 ret = sock_recv_errqueue(sock->sk, m, total_len,
2637                                          SOL_PACKET, TUN_TX_TIMESTAMP);
2638                 goto out;
2639         }
2640         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2641         if (ret > (ssize_t)total_len) {
2642                 m->msg_flags |= MSG_TRUNC;
2643                 ret = flags & MSG_TRUNC ? ret : total_len;
2644         }
2645 out:
2646         tun_put(tun);
2647         return ret;
2648
2649 out_put_tun:
2650         tun_put(tun);
2651 out_free:
2652         tun_ptr_free(ptr);
2653         return ret;
2654 }
2655
2656 static int tun_ptr_peek_len(void *ptr)
2657 {
2658         if (likely(ptr)) {
2659                 if (tun_is_xdp_frame(ptr)) {
2660                         struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2661
2662                         return xdpf->len;
2663                 }
2664                 return __skb_array_len_with_tag(ptr);
2665         } else {
2666                 return 0;
2667         }
2668 }
2669
2670 static int tun_peek_len(struct socket *sock)
2671 {
2672         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2673         struct tun_struct *tun;
2674         int ret = 0;
2675
2676         tun = tun_get(tfile);
2677         if (!tun)
2678                 return 0;
2679
2680         ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2681         tun_put(tun);
2682
2683         return ret;
2684 }
2685
2686 /* Ops structure to mimic raw sockets with tun */
2687 static const struct proto_ops tun_socket_ops = {
2688         .peek_len = tun_peek_len,
2689         .sendmsg = tun_sendmsg,
2690         .recvmsg = tun_recvmsg,
2691 };
2692
2693 static struct proto tun_proto = {
2694         .name           = "tun",
2695         .owner          = THIS_MODULE,
2696         .obj_size       = sizeof(struct tun_file),
2697 };
2698
2699 static int tun_flags(struct tun_struct *tun)
2700 {
2701         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2702 }
2703
2704 static ssize_t tun_flags_show(struct device *dev, struct device_attribute *attr,
2705                               char *buf)
2706 {
2707         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2708         return sysfs_emit(buf, "0x%x\n", tun_flags(tun));
2709 }
2710
2711 static ssize_t owner_show(struct device *dev, struct device_attribute *attr,
2712                           char *buf)
2713 {
2714         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2715         return uid_valid(tun->owner)?
2716                 sysfs_emit(buf, "%u\n",
2717                            from_kuid_munged(current_user_ns(), tun->owner)) :
2718                 sysfs_emit(buf, "-1\n");
2719 }
2720
2721 static ssize_t group_show(struct device *dev, struct device_attribute *attr,
2722                           char *buf)
2723 {
2724         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2725         return gid_valid(tun->group) ?
2726                 sysfs_emit(buf, "%u\n",
2727                            from_kgid_munged(current_user_ns(), tun->group)) :
2728                 sysfs_emit(buf, "-1\n");
2729 }
2730
2731 static DEVICE_ATTR_RO(tun_flags);
2732 static DEVICE_ATTR_RO(owner);
2733 static DEVICE_ATTR_RO(group);
2734
2735 static struct attribute *tun_dev_attrs[] = {
2736         &dev_attr_tun_flags.attr,
2737         &dev_attr_owner.attr,
2738         &dev_attr_group.attr,
2739         NULL
2740 };
2741
2742 static const struct attribute_group tun_attr_group = {
2743         .attrs = tun_dev_attrs
2744 };
2745
2746 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2747 {
2748         struct tun_struct *tun;
2749         struct tun_file *tfile = file->private_data;
2750         struct net_device *dev;
2751         int err;
2752
2753         if (tfile->detached)
2754                 return -EINVAL;
2755
2756         if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2757                 if (!capable(CAP_NET_ADMIN))
2758                         return -EPERM;
2759
2760                 if (!(ifr->ifr_flags & IFF_NAPI) ||
2761                     (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2762                         return -EINVAL;
2763         }
2764
2765         dev = __dev_get_by_name(net, ifr->ifr_name);
2766         if (dev) {
2767                 if (ifr->ifr_flags & IFF_TUN_EXCL)
2768                         return -EBUSY;
2769                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2770                         tun = netdev_priv(dev);
2771                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2772                         tun = netdev_priv(dev);
2773                 else
2774                         return -EINVAL;
2775
2776                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2777                     !!(tun->flags & IFF_MULTI_QUEUE))
2778                         return -EINVAL;
2779
2780                 if (tun_not_capable(tun))
2781                         return -EPERM;
2782                 err = security_tun_dev_open(tun->security);
2783                 if (err < 0)
2784                         return err;
2785
2786                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2787                                  ifr->ifr_flags & IFF_NAPI,
2788                                  ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2789                 if (err < 0)
2790                         return err;
2791
2792                 if (tun->flags & IFF_MULTI_QUEUE &&
2793                     (tun->numqueues + tun->numdisabled > 1)) {
2794                         /* One or more queue has already been attached, no need
2795                          * to initialize the device again.
2796                          */
2797                         netdev_state_change(dev);
2798                         return 0;
2799                 }
2800
2801                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2802                               (ifr->ifr_flags & TUN_FEATURES);
2803
2804                 netdev_state_change(dev);
2805         } else {
2806                 char *name;
2807                 unsigned long flags = 0;
2808                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2809                              MAX_TAP_QUEUES : 1;
2810
2811                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2812                         return -EPERM;
2813                 err = security_tun_dev_create();
2814                 if (err < 0)
2815                         return err;
2816
2817                 /* Set dev type */
2818                 if (ifr->ifr_flags & IFF_TUN) {
2819                         /* TUN device */
2820                         flags |= IFF_TUN;
2821                         name = "tun%d";
2822                 } else if (ifr->ifr_flags & IFF_TAP) {
2823                         /* TAP device */
2824                         flags |= IFF_TAP;
2825                         name = "tap%d";
2826                 } else
2827                         return -EINVAL;
2828
2829                 if (*ifr->ifr_name)
2830                         name = ifr->ifr_name;
2831
2832                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2833                                        NET_NAME_UNKNOWN, tun_setup, queues,
2834                                        queues);
2835
2836                 if (!dev)
2837                         return -ENOMEM;
2838
2839                 dev_net_set(dev, net);
2840                 dev->rtnl_link_ops = &tun_link_ops;
2841                 dev->ifindex = tfile->ifindex;
2842                 dev->sysfs_groups[0] = &tun_attr_group;
2843
2844                 tun = netdev_priv(dev);
2845                 tun->dev = dev;
2846                 tun->flags = flags;
2847                 tun->txflt.count = 0;
2848                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2849
2850                 tun->align = NET_SKB_PAD;
2851                 tun->filter_attached = false;
2852                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2853                 tun->rx_batched = 0;
2854                 RCU_INIT_POINTER(tun->steering_prog, NULL);
2855
2856                 tun->ifr = ifr;
2857                 tun->file = file;
2858
2859                 tun_net_initialize(dev);
2860
2861                 err = register_netdevice(tun->dev);
2862                 if (err < 0) {
2863                         free_netdev(dev);
2864                         return err;
2865                 }
2866                 /* free_netdev() won't check refcnt, to avoid race
2867                  * with dev_put() we need publish tun after registration.
2868                  */
2869                 rcu_assign_pointer(tfile->tun, tun);
2870         }
2871
2872         if (ifr->ifr_flags & IFF_NO_CARRIER)
2873                 netif_carrier_off(tun->dev);
2874         else
2875                 netif_carrier_on(tun->dev);
2876
2877         /* Make sure persistent devices do not get stuck in
2878          * xoff state.
2879          */
2880         if (netif_running(tun->dev))
2881                 netif_tx_wake_all_queues(tun->dev);
2882
2883         strcpy(ifr->ifr_name, tun->dev->name);
2884         return 0;
2885 }
2886
2887 static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2888 {
2889         strcpy(ifr->ifr_name, tun->dev->name);
2890
2891         ifr->ifr_flags = tun_flags(tun);
2892
2893 }
2894
2895 /* This is like a cut-down ethtool ops, except done via tun fd so no
2896  * privs required. */
2897 static int set_offload(struct tun_struct *tun, unsigned long arg)
2898 {
2899         netdev_features_t features = 0;
2900
2901         if (arg & TUN_F_CSUM) {
2902                 features |= NETIF_F_HW_CSUM;
2903                 arg &= ~TUN_F_CSUM;
2904
2905                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2906                         if (arg & TUN_F_TSO_ECN) {
2907                                 features |= NETIF_F_TSO_ECN;
2908                                 arg &= ~TUN_F_TSO_ECN;
2909                         }
2910                         if (arg & TUN_F_TSO4)
2911                                 features |= NETIF_F_TSO;
2912                         if (arg & TUN_F_TSO6)
2913                                 features |= NETIF_F_TSO6;
2914                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2915                 }
2916
2917                 arg &= ~TUN_F_UFO;
2918
2919                 /* TODO: for now USO4 and USO6 should work simultaneously */
2920                 if (arg & TUN_F_USO4 && arg & TUN_F_USO6) {
2921                         features |= NETIF_F_GSO_UDP_L4;
2922                         arg &= ~(TUN_F_USO4 | TUN_F_USO6);
2923                 }
2924         }
2925
2926         /* This gives the user a way to test for new features in future by
2927          * trying to set them. */
2928         if (arg)
2929                 return -EINVAL;
2930
2931         tun->set_features = features;
2932         tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2933         tun->dev->wanted_features |= features;
2934         netdev_update_features(tun->dev);
2935
2936         return 0;
2937 }
2938
2939 static void tun_detach_filter(struct tun_struct *tun, int n)
2940 {
2941         int i;
2942         struct tun_file *tfile;
2943
2944         for (i = 0; i < n; i++) {
2945                 tfile = rtnl_dereference(tun->tfiles[i]);
2946                 lock_sock(tfile->socket.sk);
2947                 sk_detach_filter(tfile->socket.sk);
2948                 release_sock(tfile->socket.sk);
2949         }
2950
2951         tun->filter_attached = false;
2952 }
2953
2954 static int tun_attach_filter(struct tun_struct *tun)
2955 {
2956         int i, ret = 0;
2957         struct tun_file *tfile;
2958
2959         for (i = 0; i < tun->numqueues; i++) {
2960                 tfile = rtnl_dereference(tun->tfiles[i]);
2961                 lock_sock(tfile->socket.sk);
2962                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2963                 release_sock(tfile->socket.sk);
2964                 if (ret) {
2965                         tun_detach_filter(tun, i);
2966                         return ret;
2967                 }
2968         }
2969
2970         tun->filter_attached = true;
2971         return ret;
2972 }
2973
2974 static void tun_set_sndbuf(struct tun_struct *tun)
2975 {
2976         struct tun_file *tfile;
2977         int i;
2978
2979         for (i = 0; i < tun->numqueues; i++) {
2980                 tfile = rtnl_dereference(tun->tfiles[i]);
2981                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2982         }
2983 }
2984
2985 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2986 {
2987         struct tun_file *tfile = file->private_data;
2988         struct tun_struct *tun;
2989         int ret = 0;
2990
2991         rtnl_lock();
2992
2993         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2994                 tun = tfile->detached;
2995                 if (!tun) {
2996                         ret = -EINVAL;
2997                         goto unlock;
2998                 }
2999                 ret = security_tun_dev_attach_queue(tun->security);
3000                 if (ret < 0)
3001                         goto unlock;
3002                 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
3003                                  tun->flags & IFF_NAPI_FRAGS, true);
3004         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
3005                 tun = rtnl_dereference(tfile->tun);
3006                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
3007                         ret = -EINVAL;
3008                 else
3009                         __tun_detach(tfile, false);
3010         } else
3011                 ret = -EINVAL;
3012
3013         if (ret >= 0)
3014                 netdev_state_change(tun->dev);
3015
3016 unlock:
3017         rtnl_unlock();
3018         return ret;
3019 }
3020
3021 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog __rcu **prog_p,
3022                         void __user *data)
3023 {
3024         struct bpf_prog *prog;
3025         int fd;
3026
3027         if (copy_from_user(&fd, data, sizeof(fd)))
3028                 return -EFAULT;
3029
3030         if (fd == -1) {
3031                 prog = NULL;
3032         } else {
3033                 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
3034                 if (IS_ERR(prog))
3035                         return PTR_ERR(prog);
3036         }
3037
3038         return __tun_set_ebpf(tun, prog_p, prog);
3039 }
3040
3041 /* Return correct value for tun->dev->addr_len based on tun->dev->type. */
3042 static unsigned char tun_get_addr_len(unsigned short type)
3043 {
3044         switch (type) {
3045         case ARPHRD_IP6GRE:
3046         case ARPHRD_TUNNEL6:
3047                 return sizeof(struct in6_addr);
3048         case ARPHRD_IPGRE:
3049         case ARPHRD_TUNNEL:
3050         case ARPHRD_SIT:
3051                 return 4;
3052         case ARPHRD_ETHER:
3053                 return ETH_ALEN;
3054         case ARPHRD_IEEE802154:
3055         case ARPHRD_IEEE802154_MONITOR:
3056                 return IEEE802154_EXTENDED_ADDR_LEN;
3057         case ARPHRD_PHONET_PIPE:
3058         case ARPHRD_PPP:
3059         case ARPHRD_NONE:
3060                 return 0;
3061         case ARPHRD_6LOWPAN:
3062                 return EUI64_ADDR_LEN;
3063         case ARPHRD_FDDI:
3064                 return FDDI_K_ALEN;
3065         case ARPHRD_HIPPI:
3066                 return HIPPI_ALEN;
3067         case ARPHRD_IEEE802:
3068                 return FC_ALEN;
3069         case ARPHRD_ROSE:
3070                 return ROSE_ADDR_LEN;
3071         case ARPHRD_NETROM:
3072                 return AX25_ADDR_LEN;
3073         case ARPHRD_LOCALTLK:
3074                 return LTALK_ALEN;
3075         default:
3076                 return 0;
3077         }
3078 }
3079
3080 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
3081                             unsigned long arg, int ifreq_len)
3082 {
3083         struct tun_file *tfile = file->private_data;
3084         struct net *net = sock_net(&tfile->sk);
3085         struct tun_struct *tun;
3086         void __user* argp = (void __user*)arg;
3087         unsigned int carrier;
3088         struct ifreq ifr;
3089         kuid_t owner;
3090         kgid_t group;
3091         int ifindex;
3092         int sndbuf;
3093         int vnet_hdr_sz;
3094         int le;
3095         int ret;
3096         bool do_notify = false;
3097
3098         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3099             (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3100                 if (copy_from_user(&ifr, argp, ifreq_len))
3101                         return -EFAULT;
3102         } else {
3103                 memset(&ifr, 0, sizeof(ifr));
3104         }
3105         if (cmd == TUNGETFEATURES) {
3106                 /* Currently this just means: "what IFF flags are valid?".
3107                  * This is needed because we never checked for invalid flags on
3108                  * TUNSETIFF.
3109                  */
3110                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_CARRIER |
3111                                 TUN_FEATURES, (unsigned int __user*)argp);
3112         } else if (cmd == TUNSETQUEUE) {
3113                 return tun_set_queue(file, &ifr);
3114         } else if (cmd == SIOCGSKNS) {
3115                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3116                         return -EPERM;
3117                 return open_related_ns(&net->ns, get_net_ns);
3118         }
3119
3120         rtnl_lock();
3121
3122         tun = tun_get(tfile);
3123         if (cmd == TUNSETIFF) {
3124                 ret = -EEXIST;
3125                 if (tun)
3126                         goto unlock;
3127
3128                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3129
3130                 ret = tun_set_iff(net, file, &ifr);
3131
3132                 if (ret)
3133                         goto unlock;
3134
3135                 if (copy_to_user(argp, &ifr, ifreq_len))
3136                         ret = -EFAULT;
3137                 goto unlock;
3138         }
3139         if (cmd == TUNSETIFINDEX) {
3140                 ret = -EPERM;
3141                 if (tun)
3142                         goto unlock;
3143
3144                 ret = -EFAULT;
3145                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3146                         goto unlock;
3147                 ret = -EINVAL;
3148                 if (ifindex < 0)
3149                         goto unlock;
3150                 ret = 0;
3151                 tfile->ifindex = ifindex;
3152                 goto unlock;
3153         }
3154
3155         ret = -EBADFD;
3156         if (!tun)
3157                 goto unlock;
3158
3159         netif_info(tun, drv, tun->dev, "tun_chr_ioctl cmd %u\n", cmd);
3160
3161         net = dev_net(tun->dev);
3162         ret = 0;
3163         switch (cmd) {
3164         case TUNGETIFF:
3165                 tun_get_iff(tun, &ifr);
3166
3167                 if (tfile->detached)
3168                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
3169                 if (!tfile->socket.sk->sk_filter)
3170                         ifr.ifr_flags |= IFF_NOFILTER;
3171
3172                 if (copy_to_user(argp, &ifr, ifreq_len))
3173                         ret = -EFAULT;
3174                 break;
3175
3176         case TUNSETNOCSUM:
3177                 /* Disable/Enable checksum */
3178
3179                 /* [unimplemented] */
3180                 netif_info(tun, drv, tun->dev, "ignored: set checksum %s\n",
3181                            arg ? "disabled" : "enabled");
3182                 break;
3183
3184         case TUNSETPERSIST:
3185                 /* Disable/Enable persist mode. Keep an extra reference to the
3186                  * module to prevent the module being unprobed.
3187                  */
3188                 if (arg && !(tun->flags & IFF_PERSIST)) {
3189                         tun->flags |= IFF_PERSIST;
3190                         __module_get(THIS_MODULE);
3191                         do_notify = true;
3192                 }
3193                 if (!arg && (tun->flags & IFF_PERSIST)) {
3194                         tun->flags &= ~IFF_PERSIST;
3195                         module_put(THIS_MODULE);
3196                         do_notify = true;
3197                 }
3198
3199                 netif_info(tun, drv, tun->dev, "persist %s\n",
3200                            arg ? "enabled" : "disabled");
3201                 break;
3202
3203         case TUNSETOWNER:
3204                 /* Set owner of the device */
3205                 owner = make_kuid(current_user_ns(), arg);
3206                 if (!uid_valid(owner)) {
3207                         ret = -EINVAL;
3208                         break;
3209                 }
3210                 tun->owner = owner;
3211                 do_notify = true;
3212                 netif_info(tun, drv, tun->dev, "owner set to %u\n",
3213                            from_kuid(&init_user_ns, tun->owner));
3214                 break;
3215
3216         case TUNSETGROUP:
3217                 /* Set group of the device */
3218                 group = make_kgid(current_user_ns(), arg);
3219                 if (!gid_valid(group)) {
3220                         ret = -EINVAL;
3221                         break;
3222                 }
3223                 tun->group = group;
3224                 do_notify = true;
3225                 netif_info(tun, drv, tun->dev, "group set to %u\n",
3226                            from_kgid(&init_user_ns, tun->group));
3227                 break;
3228
3229         case TUNSETLINK:
3230                 /* Only allow setting the type when the interface is down */
3231                 if (tun->dev->flags & IFF_UP) {
3232                         netif_info(tun, drv, tun->dev,
3233                                    "Linktype set failed because interface is up\n");
3234                         ret = -EBUSY;
3235                 } else {
3236                         ret = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE,
3237                                                        tun->dev);
3238                         ret = notifier_to_errno(ret);
3239                         if (ret) {
3240                                 netif_info(tun, drv, tun->dev,
3241                                            "Refused to change device type\n");
3242                                 break;
3243                         }
3244                         tun->dev->type = (int) arg;
3245                         tun->dev->addr_len = tun_get_addr_len(tun->dev->type);
3246                         netif_info(tun, drv, tun->dev, "linktype set to %d\n",
3247                                    tun->dev->type);
3248                         call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE,
3249                                                  tun->dev);
3250                 }
3251                 break;
3252
3253         case TUNSETDEBUG:
3254                 tun->msg_enable = (u32)arg;
3255                 break;
3256
3257         case TUNSETOFFLOAD:
3258                 ret = set_offload(tun, arg);
3259                 break;
3260
3261         case TUNSETTXFILTER:
3262                 /* Can be set only for TAPs */
3263                 ret = -EINVAL;
3264                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3265                         break;
3266                 ret = update_filter(&tun->txflt, (void __user *)arg);
3267                 break;
3268
3269         case SIOCGIFHWADDR:
3270                 /* Get hw address */
3271                 dev_get_mac_address(&ifr.ifr_hwaddr, net, tun->dev->name);
3272                 if (copy_to_user(argp, &ifr, ifreq_len))
3273                         ret = -EFAULT;
3274                 break;
3275
3276         case SIOCSIFHWADDR:
3277                 /* Set hw address */
3278                 ret = dev_set_mac_address_user(tun->dev, &ifr.ifr_hwaddr, NULL);
3279                 break;
3280
3281         case TUNGETSNDBUF:
3282                 sndbuf = tfile->socket.sk->sk_sndbuf;
3283                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3284                         ret = -EFAULT;
3285                 break;
3286
3287         case TUNSETSNDBUF:
3288                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3289                         ret = -EFAULT;
3290                         break;
3291                 }
3292                 if (sndbuf <= 0) {
3293                         ret = -EINVAL;
3294                         break;
3295                 }
3296
3297                 tun->sndbuf = sndbuf;
3298                 tun_set_sndbuf(tun);
3299                 break;
3300
3301         case TUNGETVNETHDRSZ:
3302                 vnet_hdr_sz = tun->vnet_hdr_sz;
3303                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3304                         ret = -EFAULT;
3305                 break;
3306
3307         case TUNSETVNETHDRSZ:
3308                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3309                         ret = -EFAULT;
3310                         break;
3311                 }
3312                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3313                         ret = -EINVAL;
3314                         break;
3315                 }
3316
3317                 tun->vnet_hdr_sz = vnet_hdr_sz;
3318                 break;
3319
3320         case TUNGETVNETLE:
3321                 le = !!(tun->flags & TUN_VNET_LE);
3322                 if (put_user(le, (int __user *)argp))
3323                         ret = -EFAULT;
3324                 break;
3325
3326         case TUNSETVNETLE:
3327                 if (get_user(le, (int __user *)argp)) {
3328                         ret = -EFAULT;
3329                         break;
3330                 }
3331                 if (le)
3332                         tun->flags |= TUN_VNET_LE;
3333                 else
3334                         tun->flags &= ~TUN_VNET_LE;
3335                 break;
3336
3337         case TUNGETVNETBE:
3338                 ret = tun_get_vnet_be(tun, argp);
3339                 break;
3340
3341         case TUNSETVNETBE:
3342                 ret = tun_set_vnet_be(tun, argp);
3343                 break;
3344
3345         case TUNATTACHFILTER:
3346                 /* Can be set only for TAPs */
3347                 ret = -EINVAL;
3348                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3349                         break;
3350                 ret = -EFAULT;
3351                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3352                         break;
3353
3354                 ret = tun_attach_filter(tun);
3355                 break;
3356
3357         case TUNDETACHFILTER:
3358                 /* Can be set only for TAPs */
3359                 ret = -EINVAL;
3360                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3361                         break;
3362                 ret = 0;
3363                 tun_detach_filter(tun, tun->numqueues);
3364                 break;
3365
3366         case TUNGETFILTER:
3367                 ret = -EINVAL;
3368                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3369                         break;
3370                 ret = -EFAULT;
3371                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3372                         break;
3373                 ret = 0;
3374                 break;
3375
3376         case TUNSETSTEERINGEBPF:
3377                 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3378                 break;
3379
3380         case TUNSETFILTEREBPF:
3381                 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3382                 break;
3383
3384         case TUNSETCARRIER:
3385                 ret = -EFAULT;
3386                 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3387                         goto unlock;
3388
3389                 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3390                 break;
3391
3392         case TUNGETDEVNETNS:
3393                 ret = -EPERM;
3394                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3395                         goto unlock;
3396                 ret = open_related_ns(&net->ns, get_net_ns);
3397                 break;
3398
3399         default:
3400                 ret = -EINVAL;
3401                 break;
3402         }
3403
3404         if (do_notify)
3405                 netdev_state_change(tun->dev);
3406
3407 unlock:
3408         rtnl_unlock();
3409         if (tun)
3410                 tun_put(tun);
3411         return ret;
3412 }
3413
3414 static long tun_chr_ioctl(struct file *file,
3415                           unsigned int cmd, unsigned long arg)
3416 {
3417         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3418 }
3419
3420 #ifdef CONFIG_COMPAT
3421 static long tun_chr_compat_ioctl(struct file *file,
3422                          unsigned int cmd, unsigned long arg)
3423 {
3424         switch (cmd) {
3425         case TUNSETIFF:
3426         case TUNGETIFF:
3427         case TUNSETTXFILTER:
3428         case TUNGETSNDBUF:
3429         case TUNSETSNDBUF:
3430         case SIOCGIFHWADDR:
3431         case SIOCSIFHWADDR:
3432                 arg = (unsigned long)compat_ptr(arg);
3433                 break;
3434         default:
3435                 arg = (compat_ulong_t)arg;
3436                 break;
3437         }
3438
3439         /*
3440          * compat_ifreq is shorter than ifreq, so we must not access beyond
3441          * the end of that structure. All fields that are used in this
3442          * driver are compatible though, we don't need to convert the
3443          * contents.
3444          */
3445         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3446 }
3447 #endif /* CONFIG_COMPAT */
3448
3449 static int tun_chr_fasync(int fd, struct file *file, int on)
3450 {
3451         struct tun_file *tfile = file->private_data;
3452         int ret;
3453
3454         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3455                 goto out;
3456
3457         if (on) {
3458                 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3459                 tfile->flags |= TUN_FASYNC;
3460         } else
3461                 tfile->flags &= ~TUN_FASYNC;
3462         ret = 0;
3463 out:
3464         return ret;
3465 }
3466
3467 static int tun_chr_open(struct inode *inode, struct file * file)
3468 {
3469         struct net *net = current->nsproxy->net_ns;
3470         struct tun_file *tfile;
3471
3472         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3473                                             &tun_proto, 0);
3474         if (!tfile)
3475                 return -ENOMEM;
3476         if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3477                 sk_free(&tfile->sk);
3478                 return -ENOMEM;
3479         }
3480
3481         mutex_init(&tfile->napi_mutex);
3482         RCU_INIT_POINTER(tfile->tun, NULL);
3483         tfile->flags = 0;
3484         tfile->ifindex = 0;
3485
3486         init_waitqueue_head(&tfile->socket.wq.wait);
3487
3488         tfile->socket.file = file;
3489         tfile->socket.ops = &tun_socket_ops;
3490
3491         sock_init_data_uid(&tfile->socket, &tfile->sk, current_fsuid());
3492
3493         tfile->sk.sk_write_space = tun_sock_write_space;
3494         tfile->sk.sk_sndbuf = INT_MAX;
3495
3496         file->private_data = tfile;
3497         INIT_LIST_HEAD(&tfile->next);
3498
3499         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3500
3501         /* tun groks IOCB_NOWAIT just fine, mark it as such */
3502         file->f_mode |= FMODE_NOWAIT;
3503         return 0;
3504 }
3505
3506 static int tun_chr_close(struct inode *inode, struct file *file)
3507 {
3508         struct tun_file *tfile = file->private_data;
3509
3510         tun_detach(tfile, true);
3511
3512         return 0;
3513 }
3514
3515 #ifdef CONFIG_PROC_FS
3516 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3517 {
3518         struct tun_file *tfile = file->private_data;
3519         struct tun_struct *tun;
3520         struct ifreq ifr;
3521
3522         memset(&ifr, 0, sizeof(ifr));
3523
3524         rtnl_lock();
3525         tun = tun_get(tfile);
3526         if (tun)
3527                 tun_get_iff(tun, &ifr);
3528         rtnl_unlock();
3529
3530         if (tun)
3531                 tun_put(tun);
3532
3533         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3534 }
3535 #endif
3536
3537 static const struct file_operations tun_fops = {
3538         .owner  = THIS_MODULE,
3539         .llseek = no_llseek,
3540         .read_iter  = tun_chr_read_iter,
3541         .write_iter = tun_chr_write_iter,
3542         .poll   = tun_chr_poll,
3543         .unlocked_ioctl = tun_chr_ioctl,
3544 #ifdef CONFIG_COMPAT
3545         .compat_ioctl = tun_chr_compat_ioctl,
3546 #endif
3547         .open   = tun_chr_open,
3548         .release = tun_chr_close,
3549         .fasync = tun_chr_fasync,
3550 #ifdef CONFIG_PROC_FS
3551         .show_fdinfo = tun_chr_show_fdinfo,
3552 #endif
3553 };
3554
3555 static struct miscdevice tun_miscdev = {
3556         .minor = TUN_MINOR,
3557         .name = "tun",
3558         .nodename = "net/tun",
3559         .fops = &tun_fops,
3560 };
3561
3562 /* ethtool interface */
3563
3564 static void tun_default_link_ksettings(struct net_device *dev,
3565                                        struct ethtool_link_ksettings *cmd)
3566 {
3567         ethtool_link_ksettings_zero_link_mode(cmd, supported);
3568         ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3569         cmd->base.speed         = SPEED_10000;
3570         cmd->base.duplex        = DUPLEX_FULL;
3571         cmd->base.port          = PORT_TP;
3572         cmd->base.phy_address   = 0;
3573         cmd->base.autoneg       = AUTONEG_DISABLE;
3574 }
3575
3576 static int tun_get_link_ksettings(struct net_device *dev,
3577                                   struct ethtool_link_ksettings *cmd)
3578 {
3579         struct tun_struct *tun = netdev_priv(dev);
3580
3581         memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3582         return 0;
3583 }
3584
3585 static int tun_set_link_ksettings(struct net_device *dev,
3586                                   const struct ethtool_link_ksettings *cmd)
3587 {
3588         struct tun_struct *tun = netdev_priv(dev);
3589
3590         memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3591         return 0;
3592 }
3593
3594 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3595 {
3596         struct tun_struct *tun = netdev_priv(dev);
3597
3598         strscpy(info->driver, DRV_NAME, sizeof(info->driver));
3599         strscpy(info->version, DRV_VERSION, sizeof(info->version));
3600
3601         switch (tun->flags & TUN_TYPE_MASK) {
3602         case IFF_TUN:
3603                 strscpy(info->bus_info, "tun", sizeof(info->bus_info));
3604                 break;
3605         case IFF_TAP:
3606                 strscpy(info->bus_info, "tap", sizeof(info->bus_info));
3607                 break;
3608         }
3609 }
3610
3611 static u32 tun_get_msglevel(struct net_device *dev)
3612 {
3613         struct tun_struct *tun = netdev_priv(dev);
3614
3615         return tun->msg_enable;
3616 }
3617
3618 static void tun_set_msglevel(struct net_device *dev, u32 value)
3619 {
3620         struct tun_struct *tun = netdev_priv(dev);
3621
3622         tun->msg_enable = value;
3623 }
3624
3625 static int tun_get_coalesce(struct net_device *dev,
3626                             struct ethtool_coalesce *ec,
3627                             struct kernel_ethtool_coalesce *kernel_coal,
3628                             struct netlink_ext_ack *extack)
3629 {
3630         struct tun_struct *tun = netdev_priv(dev);
3631
3632         ec->rx_max_coalesced_frames = tun->rx_batched;
3633
3634         return 0;
3635 }
3636
3637 static int tun_set_coalesce(struct net_device *dev,
3638                             struct ethtool_coalesce *ec,
3639                             struct kernel_ethtool_coalesce *kernel_coal,
3640                             struct netlink_ext_ack *extack)
3641 {
3642         struct tun_struct *tun = netdev_priv(dev);
3643
3644         if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3645                 tun->rx_batched = NAPI_POLL_WEIGHT;
3646         else
3647                 tun->rx_batched = ec->rx_max_coalesced_frames;
3648
3649         return 0;
3650 }
3651
3652 static void tun_get_channels(struct net_device *dev,
3653                              struct ethtool_channels *channels)
3654 {
3655         struct tun_struct *tun = netdev_priv(dev);
3656
3657         channels->combined_count = tun->numqueues;
3658         channels->max_combined = tun->flags & IFF_MULTI_QUEUE ? MAX_TAP_QUEUES : 1;
3659 }
3660
3661 static const struct ethtool_ops tun_ethtool_ops = {
3662         .supported_coalesce_params = ETHTOOL_COALESCE_RX_MAX_FRAMES,
3663         .get_drvinfo    = tun_get_drvinfo,
3664         .get_msglevel   = tun_get_msglevel,
3665         .set_msglevel   = tun_set_msglevel,
3666         .get_link       = ethtool_op_get_link,
3667         .get_channels   = tun_get_channels,
3668         .get_ts_info    = ethtool_op_get_ts_info,
3669         .get_coalesce   = tun_get_coalesce,
3670         .set_coalesce   = tun_set_coalesce,
3671         .get_link_ksettings = tun_get_link_ksettings,
3672         .set_link_ksettings = tun_set_link_ksettings,
3673 };
3674
3675 static int tun_queue_resize(struct tun_struct *tun)
3676 {
3677         struct net_device *dev = tun->dev;
3678         struct tun_file *tfile;
3679         struct ptr_ring **rings;
3680         int n = tun->numqueues + tun->numdisabled;
3681         int ret, i;
3682
3683         rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3684         if (!rings)
3685                 return -ENOMEM;
3686
3687         for (i = 0; i < tun->numqueues; i++) {
3688                 tfile = rtnl_dereference(tun->tfiles[i]);
3689                 rings[i] = &tfile->tx_ring;
3690         }
3691         list_for_each_entry(tfile, &tun->disabled, next)
3692                 rings[i++] = &tfile->tx_ring;
3693
3694         ret = ptr_ring_resize_multiple(rings, n,
3695                                        dev->tx_queue_len, GFP_KERNEL,
3696                                        tun_ptr_free);
3697
3698         kfree(rings);
3699         return ret;
3700 }
3701
3702 static int tun_device_event(struct notifier_block *unused,
3703                             unsigned long event, void *ptr)
3704 {
3705         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3706         struct tun_struct *tun = netdev_priv(dev);
3707         int i;
3708
3709         if (dev->rtnl_link_ops != &tun_link_ops)
3710                 return NOTIFY_DONE;
3711
3712         switch (event) {
3713         case NETDEV_CHANGE_TX_QUEUE_LEN:
3714                 if (tun_queue_resize(tun))
3715                         return NOTIFY_BAD;
3716                 break;
3717         case NETDEV_UP:
3718                 for (i = 0; i < tun->numqueues; i++) {
3719                         struct tun_file *tfile;
3720
3721                         tfile = rtnl_dereference(tun->tfiles[i]);
3722                         tfile->socket.sk->sk_write_space(tfile->socket.sk);
3723                 }
3724                 break;
3725         default:
3726                 break;
3727         }
3728
3729         return NOTIFY_DONE;
3730 }
3731
3732 static struct notifier_block tun_notifier_block __read_mostly = {
3733         .notifier_call  = tun_device_event,
3734 };
3735
3736 static int __init tun_init(void)
3737 {
3738         int ret = 0;
3739
3740         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3741
3742         ret = rtnl_link_register(&tun_link_ops);
3743         if (ret) {
3744                 pr_err("Can't register link_ops\n");
3745                 goto err_linkops;
3746         }
3747
3748         ret = misc_register(&tun_miscdev);
3749         if (ret) {
3750                 pr_err("Can't register misc device %d\n", TUN_MINOR);
3751                 goto err_misc;
3752         }
3753
3754         ret = register_netdevice_notifier(&tun_notifier_block);
3755         if (ret) {
3756                 pr_err("Can't register netdevice notifier\n");
3757                 goto err_notifier;
3758         }
3759
3760         return  0;
3761
3762 err_notifier:
3763         misc_deregister(&tun_miscdev);
3764 err_misc:
3765         rtnl_link_unregister(&tun_link_ops);
3766 err_linkops:
3767         return ret;
3768 }
3769
3770 static void __exit tun_cleanup(void)
3771 {
3772         misc_deregister(&tun_miscdev);
3773         rtnl_link_unregister(&tun_link_ops);
3774         unregister_netdevice_notifier(&tun_notifier_block);
3775 }
3776
3777 /* Get an underlying socket object from tun file.  Returns error unless file is
3778  * attached to a device.  The returned object works like a packet socket, it
3779  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
3780  * holding a reference to the file for as long as the socket is in use. */
3781 struct socket *tun_get_socket(struct file *file)
3782 {
3783         struct tun_file *tfile;
3784         if (file->f_op != &tun_fops)
3785                 return ERR_PTR(-EINVAL);
3786         tfile = file->private_data;
3787         if (!tfile)
3788                 return ERR_PTR(-EBADFD);
3789         return &tfile->socket;
3790 }
3791 EXPORT_SYMBOL_GPL(tun_get_socket);
3792
3793 struct ptr_ring *tun_get_tx_ring(struct file *file)
3794 {
3795         struct tun_file *tfile;
3796
3797         if (file->f_op != &tun_fops)
3798                 return ERR_PTR(-EINVAL);
3799         tfile = file->private_data;
3800         if (!tfile)
3801                 return ERR_PTR(-EBADFD);
3802         return &tfile->tx_ring;
3803 }
3804 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3805
3806 module_init(tun_init);
3807 module_exit(tun_cleanup);
3808 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3809 MODULE_AUTHOR(DRV_COPYRIGHT);
3810 MODULE_LICENSE("GPL");
3811 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3812 MODULE_ALIAS("devname:net/tun");