drivers/net/tun.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  TUN - Universal TUN/TAP device driver.
   4  *  Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
   5  *
   6  *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
   7  */
   8
   9 /*
  10  *  Changes:
  11  *
  12  *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
  13  *    Add TUNSETLINK ioctl to set the link encapsulation
  14  *
  15  *  Mark Smith <markzzzsmith@yahoo.com.au>
  16  *    Use eth_random_addr() for tap MAC address.
  17  *
  18  *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
  19  *    Fixes in packet dropping, queue length setting and queue wakeup.
  20  *    Increased default tx queue length.
  21  *    Added ethtool API.
  22  *    Minor cleanups
  23  *
  24  *  Daniel Podlejski <underley@underley.eu.org>
  25  *    Modifications for 2.3.99-pre5 kernel.
  26  */
  27
  28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  29
  30 #define DRV_NAME        "tun"
  31 #define DRV_VERSION     "1.6"
  32 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  33 #define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
  34
  35 #include <linux/module.h>
  36 #include <linux/errno.h>
  37 #include <linux/kernel.h>
  38 #include <linux/sched/signal.h>
  39 #include <linux/major.h>
  40 #include <linux/slab.h>
  41 #include <linux/poll.h>
  42 #include <linux/fcntl.h>
  43 #include <linux/init.h>
  44 #include <linux/skbuff.h>
  45 #include <linux/netdevice.h>
  46 #include <linux/etherdevice.h>
  47 #include <linux/miscdevice.h>
  48 #include <linux/ethtool.h>
  49 #include <linux/rtnetlink.h>
  50 #include <linux/compat.h>
  51 #include <linux/if.h>
  52 #include <linux/if_arp.h>
  53 #include <linux/if_ether.h>
  54 #include <linux/if_tun.h>
  55 #include <linux/if_vlan.h>
  56 #include <linux/crc32.h>
  57 #include <linux/nsproxy.h>
  58 #include <linux/virtio_net.h>
  59 #include <linux/rcupdate.h>
  60 #include <net/net_namespace.h>
  61 #include <net/netns/generic.h>
  62 #include <net/rtnetlink.h>
  63 #include <net/sock.h>
  64 #include <net/xdp.h>
  65 #include <net/ip_tunnels.h>
  66 #include <linux/seq_file.h>
  67 #include <linux/uio.h>
  68 #include <linux/skb_array.h>
  69 #include <linux/bpf.h>
  70 #include <linux/bpf_trace.h>
  71 #include <linux/mutex.h>
  72 #include <linux/ieee802154.h>
  73 #include <linux/if_ltalk.h>
  74 #include <uapi/linux/if_fddi.h>
  75 #include <uapi/linux/if_hippi.h>
  76 #include <uapi/linux/if_fc.h>
  77 #include <net/ax25.h>
  78 #include <net/rose.h>
  79 #include <net/6lowpan.h>
  80
  81 #include <linux/uaccess.h>
  82 #include <linux/proc_fs.h>
  83
  84 static void tun_default_link_ksettings(struct net_device *dev,
  85                                        struct ethtool_link_ksettings *cmd);
  86
  87 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
  88
  89 /* TUN device flags */
  90
  91 /* IFF_ATTACH_QUEUE is never stored in device flags,
  92  * overload it to mean fasync when stored there.
  93  */
  94 #define TUN_FASYNC      IFF_ATTACH_QUEUE
  95 /* High bits in flags field are unused. */
  96 #define TUN_VNET_LE     0x80000000
  97 #define TUN_VNET_BE     0x40000000
  98
  99 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
 100                       IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
 101
 102 #define GOODCOPY_LEN 128
 103
 104 #define FLT_EXACT_COUNT 8
 105 struct tap_filter {
 106         unsigned int    count;    /* Number of addrs. Zero means disabled */
 107         u32             mask[2];  /* Mask of the hashed addrs */
 108         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 109 };
 110
 111 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
 112  * to max number of VCPUs in guest. */
 113 #define MAX_TAP_QUEUES 256
 114 #define MAX_TAP_FLOWS  4096
 115
 116 #define TUN_FLOW_EXPIRE (3 * HZ)
 117
 118 /* A tun_file connects an open character device to a tuntap netdevice. It
 119  * also contains all socket related structures (except sock_fprog and tap_filter)
 120  * to serve as one transmit queue for tuntap device. The sock_fprog and
 121  * tap_filter were kept in tun_struct since they were used for filtering for the
 122  * netdevice not for a specific queue (at least I didn't see the requirement for
 123  * this).
 124  *
 125  * RCU usage:
 126  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
 127  * other can only be read while rcu_read_lock or rtnl_lock is held.
 128  */
 129 struct tun_file {
 130         struct sock sk;
 131         struct socket socket;
 132         struct tun_struct __rcu *tun;
 133         struct fasync_struct *fasync;
 134         /* only used for fasnyc */
 135         unsigned int flags;
 136         union {
 137                 u16 queue_index;
 138                 unsigned int ifindex;
 139         };
 140         struct napi_struct napi;
 141         bool napi_enabled;
 142         bool napi_frags_enabled;
 143         struct mutex napi_mutex;        /* Protects access to the above napi */
 144         struct list_head next;
 145         struct tun_struct *detached;
 146         struct ptr_ring tx_ring;
 147         struct xdp_rxq_info xdp_rxq;
 148 };
 149
 150 struct tun_page {
 151         struct page *page;
 152         int count;
 153 };
 154
 155 struct tun_flow_entry {
 156         struct hlist_node hash_link;
 157         struct rcu_head rcu;
 158         struct tun_struct *tun;
 159
 160         u32 rxhash;
 161         u32 rps_rxhash;
 162         int queue_index;
 163         unsigned long updated ____cacheline_aligned_in_smp;
 164 };
 165
 166 #define TUN_NUM_FLOW_ENTRIES 1024
 167 #define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
 168
 169 struct tun_prog {
 170         struct rcu_head rcu;
 171         struct bpf_prog *prog;
 172 };
 173
 174 /* Since the socket were moved to tun_file, to preserve the behavior of persist
 175  * device, socket filter, sndbuf and vnet header size were restore when the
 176  * file were attached to a persist device.
 177  */
 178 struct tun_struct {
 179         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
 180         unsigned int            numqueues;
 181         unsigned int            flags;
 182         kuid_t                  owner;
 183         kgid_t                  group;
 184
 185         struct net_device       *dev;
 186         netdev_features_t       set_features;
 187 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 188                           NETIF_F_TSO6 | NETIF_F_GSO_UDP_L4)
 189
 190         int                     align;
 191         int                     vnet_hdr_sz;
 192         int                     sndbuf;
 193         struct tap_filter       txflt;
 194         struct sock_fprog       fprog;
 195         /* protected by rtnl lock */
 196         bool                    filter_attached;
 197         u32                     msg_enable;
 198         spinlock_t lock;
 199         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 200         struct timer_list flow_gc_timer;
 201         unsigned long ageing_time;
 202         unsigned int numdisabled;
 203         struct list_head disabled;
 204         void *security;
 205         u32 flow_count;
 206         u32 rx_batched;
 207         atomic_long_t rx_frame_errors;
 208         struct bpf_prog __rcu *xdp_prog;
 209         struct tun_prog __rcu *steering_prog;
 210         struct tun_prog __rcu *filter_prog;
 211         struct ethtool_link_ksettings link_ksettings;
 212         /* init args */
 213         struct file *file;
 214         struct ifreq *ifr;
 215 };
 216
 217 struct veth {
 218         __be16 h_vlan_proto;
 219         __be16 h_vlan_TCI;
 220 };
 221
 222 static void tun_flow_init(struct tun_struct *tun);
 223 static void tun_flow_uninit(struct tun_struct *tun);
 224
 225 static int tun_napi_receive(struct napi_struct *napi, int budget)
 226 {
 227         struct tun_file *tfile = container_of(napi, struct tun_file, napi);
 228         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
 229         struct sk_buff_head process_queue;
 230         struct sk_buff *skb;
 231         int received = 0;
 232
 233         __skb_queue_head_init(&process_queue);
 234
 235         spin_lock(&queue->lock);
 236         skb_queue_splice_tail_init(queue, &process_queue);
 237         spin_unlock(&queue->lock);
 238
 239         while (received < budget && (skb = __skb_dequeue(&process_queue))) {
 240                 napi_gro_receive(napi, skb);
 241                 ++received;
 242         }
 243
 244         if (!skb_queue_empty(&process_queue)) {
 245                 spin_lock(&queue->lock);
 246                 skb_queue_splice(&process_queue, queue);
 247                 spin_unlock(&queue->lock);
 248         }
 249
 250         return received;
 251 }
 252
 253 static int tun_napi_poll(struct napi_struct *napi, int budget)
 254 {
 255         unsigned int received;
 256
 257         received = tun_napi_receive(napi, budget);
 258
 259         if (received < budget)
 260                 napi_complete_done(napi, received);
 261
 262         return received;
 263 }
 264
 265 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
 266                           bool napi_en, bool napi_frags)
 267 {
 268         tfile->napi_enabled = napi_en;
 269         tfile->napi_frags_enabled = napi_en && napi_frags;
 270         if (napi_en) {
 271                 netif_napi_add_tx(tun->dev, &tfile->napi, tun_napi_poll);
 272                 napi_enable(&tfile->napi);
 273         }
 274 }
 275
 276 static void tun_napi_enable(struct tun_file *tfile)
 277 {
 278         if (tfile->napi_enabled)
 279                 napi_enable(&tfile->napi);
 280 }
 281
 282 static void tun_napi_disable(struct tun_file *tfile)
 283 {
 284         if (tfile->napi_enabled)
 285                 napi_disable(&tfile->napi);
 286 }
 287
 288 static void tun_napi_del(struct tun_file *tfile)
 289 {
 290         if (tfile->napi_enabled)
 291                 netif_napi_del(&tfile->napi);
 292 }
 293
 294 static bool tun_napi_frags_enabled(const struct tun_file *tfile)
 295 {
 296         return tfile->napi_frags_enabled;
 297 }
 298
 299 #ifdef CONFIG_TUN_VNET_CROSS_LE
 300 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 301 {
 302         return tun->flags & TUN_VNET_BE ? false :
 303                 virtio_legacy_is_little_endian();
 304 }
 305
 306 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 307 {
 308         int be = !!(tun->flags & TUN_VNET_BE);
 309
 310         if (put_user(be, argp))
 311                 return -EFAULT;
 312
 313         return 0;
 314 }
 315
 316 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 317 {
 318         int be;
 319
 320         if (get_user(be, argp))
 321                 return -EFAULT;
 322
 323         if (be)
 324                 tun->flags |= TUN_VNET_BE;
 325         else
 326                 tun->flags &= ~TUN_VNET_BE;
 327
 328         return 0;
 329 }
 330 #else
 331 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 332 {
 333         return virtio_legacy_is_little_endian();
 334 }
 335
 336 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 337 {
 338         return -EINVAL;
 339 }
 340
 341 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 342 {
 343         return -EINVAL;
 344 }
 345 #endif /* CONFIG_TUN_VNET_CROSS_LE */
 346
 347 static inline bool tun_is_little_endian(struct tun_struct *tun)
 348 {
 349         return tun->flags & TUN_VNET_LE ||
 350                 tun_legacy_is_little_endian(tun);
 351 }
 352
 353 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
 354 {
 355         return __virtio16_to_cpu(tun_is_little_endian(tun), val);
 356 }
 357
 358 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
 359 {
 360         return __cpu_to_virtio16(tun_is_little_endian(tun), val);
 361 }
 362
 363 static inline u32 tun_hashfn(u32 rxhash)
 364 {
 365         return rxhash & TUN_MASK_FLOW_ENTRIES;
 366 }
 367
 368 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 369 {
 370         struct tun_flow_entry *e;
 371
 372         hlist_for_each_entry_rcu(e, head, hash_link) {
 373                 if (e->rxhash == rxhash)
 374                         return e;
 375         }
 376         return NULL;
 377 }
 378
 379 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 380                                               struct hlist_head *head,
 381                                               u32 rxhash, u16 queue_index)
 382 {
 383         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 384
 385         if (e) {
 386                 netif_info(tun, tx_queued, tun->dev,
 387                            "create flow: hash %u index %u\n",
 388                            rxhash, queue_index);
 389                 e->updated = jiffies;
 390                 e->rxhash = rxhash;
 391                 e->rps_rxhash = 0;
 392                 e->queue_index = queue_index;
 393                 e->tun = tun;
 394                 hlist_add_head_rcu(&e->hash_link, head);
 395                 ++tun->flow_count;
 396         }
 397         return e;
 398 }
 399
 400 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 401 {
 402         netif_info(tun, tx_queued, tun->dev, "delete flow: hash %u index %u\n",
 403                    e->rxhash, e->queue_index);
 404         hlist_del_rcu(&e->hash_link);
 405         kfree_rcu(e, rcu);
 406         --tun->flow_count;
 407 }
 408
 409 static void tun_flow_flush(struct tun_struct *tun)
 410 {
 411         int i;
 412
 413         spin_lock_bh(&tun->lock);
 414         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 415                 struct tun_flow_entry *e;
 416                 struct hlist_node *n;
 417
 418                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 419                         tun_flow_delete(tun, e);
 420         }
 421         spin_unlock_bh(&tun->lock);
 422 }
 423
 424 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 425 {
 426         int i;
 427
 428         spin_lock_bh(&tun->lock);
 429         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 430                 struct tun_flow_entry *e;
 431                 struct hlist_node *n;
 432
 433                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 434                         if (e->queue_index == queue_index)
 435                                 tun_flow_delete(tun, e);
 436                 }
 437         }
 438         spin_unlock_bh(&tun->lock);
 439 }
 440
 441 static void tun_flow_cleanup(struct timer_list *t)
 442 {
 443         struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
 444         unsigned long delay = tun->ageing_time;
 445         unsigned long next_timer = jiffies + delay;
 446         unsigned long count = 0;
 447         int i;
 448
 449         spin_lock(&tun->lock);
 450         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 451                 struct tun_flow_entry *e;
 452                 struct hlist_node *n;
 453
 454                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 455                         unsigned long this_timer;
 456
 457                         this_timer = e->updated + delay;
 458                         if (time_before_eq(this_timer, jiffies)) {
 459                                 tun_flow_delete(tun, e);
 460                                 continue;
 461                         }
 462                         count++;
 463                         if (time_before(this_timer, next_timer))
 464                                 next_timer = this_timer;
 465                 }
 466         }
 467
 468         if (count)
 469                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 470         spin_unlock(&tun->lock);
 471 }
 472
 473 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 474                             struct tun_file *tfile)
 475 {
 476         struct hlist_head *head;
 477         struct tun_flow_entry *e;
 478         unsigned long delay = tun->ageing_time;
 479         u16 queue_index = tfile->queue_index;
 480
 481         head = &tun->flows[tun_hashfn(rxhash)];
 482
 483         rcu_read_lock();
 484
 485         e = tun_flow_find(head, rxhash);
 486         if (likely(e)) {
 487                 /* TODO: keep queueing to old queue until it's empty? */
 488                 if (READ_ONCE(e->queue_index) != queue_index)
 489                         WRITE_ONCE(e->queue_index, queue_index);
 490                 if (e->updated != jiffies)
 491                         e->updated = jiffies;
 492                 sock_rps_record_flow_hash(e->rps_rxhash);
 493         } else {
 494                 spin_lock_bh(&tun->lock);
 495                 if (!tun_flow_find(head, rxhash) &&
 496                     tun->flow_count < MAX_TAP_FLOWS)
 497                         tun_flow_create(tun, head, rxhash, queue_index);
 498
 499                 if (!timer_pending(&tun->flow_gc_timer))
 500                         mod_timer(&tun->flow_gc_timer,
 501                                   round_jiffies_up(jiffies + delay));
 502                 spin_unlock_bh(&tun->lock);
 503         }
 504
 505         rcu_read_unlock();
 506 }
 507
 508 /* Save the hash received in the stack receive path and update the
 509  * flow_hash table accordingly.
 510  */
 511 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
 512 {
 513         if (unlikely(e->rps_rxhash != hash))
 514                 e->rps_rxhash = hash;
 515 }
 516
 517 /* We try to identify a flow through its rxhash. The reason that
 518  * we do not check rxq no. is because some cards(e.g 82599), chooses
 519  * the rxq based on the txq where the last packet of the flow comes. As
 520  * the userspace application move between processors, we may get a
 521  * different rxq no. here.
 522  */
 523 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 524 {
 525         struct tun_flow_entry *e;
 526         u32 txq = 0;
 527         u32 numqueues = 0;
 528
 529         numqueues = READ_ONCE(tun->numqueues);
 530
 531         txq = __skb_get_hash_symmetric(skb);
 532         e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 533         if (e) {
 534                 tun_flow_save_rps_rxhash(e, txq);
 535                 txq = e->queue_index;
 536         } else {
 537                 /* use multiply and shift instead of expensive divide */
 538                 txq = ((u64)txq * numqueues) >> 32;
 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                 rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
 657                                    NULL);
 658
 659                 --tun->numqueues;
 660                 if (clean) {
 661                         RCU_INIT_POINTER(tfile->tun, NULL);
 662                         sock_put(&tfile->sk);
 663                 } else {
 664                         tun_disable_queue(tun, tfile);
 665                         tun_napi_disable(tfile);
 666                 }
 667
 668                 synchronize_net();
 669                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 670                 /* Drop read queue */
 671                 tun_queue_purge(tfile);
 672                 tun_set_real_num_queues(tun);
 673         } else if (tfile->detached && clean) {
 674                 tun = tun_enable_queue(tfile);
 675                 sock_put(&tfile->sk);
 676         }
 677
 678         if (clean) {
 679                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 680                         netif_carrier_off(tun->dev);
 681
 682                         if (!(tun->flags & IFF_PERSIST) &&
 683                             tun->dev->reg_state == NETREG_REGISTERED)
 684                                 unregister_netdevice(tun->dev);
 685                 }
 686                 if (tun)
 687                         xdp_rxq_info_unreg(&tfile->xdp_rxq);
 688                 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
 689         }
 690 }
 691
 692 static void tun_detach(struct tun_file *tfile, bool clean)
 693 {
 694         struct tun_struct *tun;
 695         struct net_device *dev;
 696
 697         rtnl_lock();
 698         tun = rtnl_dereference(tfile->tun);
 699         dev = tun ? tun->dev : NULL;
 700         __tun_detach(tfile, clean);
 701         if (dev)
 702                 netdev_state_change(dev);
 703         rtnl_unlock();
 704
 705         if (clean)
 706                 sock_put(&tfile->sk);
 707 }
 708
 709 static void tun_detach_all(struct net_device *dev)
 710 {
 711         struct tun_struct *tun = netdev_priv(dev);
 712         struct tun_file *tfile, *tmp;
 713         int i, n = tun->numqueues;
 714
 715         for (i = 0; i < n; i++) {
 716                 tfile = rtnl_dereference(tun->tfiles[i]);
 717                 BUG_ON(!tfile);
 718                 tun_napi_disable(tfile);
 719                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 720                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 721                 RCU_INIT_POINTER(tfile->tun, NULL);
 722                 --tun->numqueues;
 723         }
 724         list_for_each_entry(tfile, &tun->disabled, next) {
 725                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 726                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 727                 RCU_INIT_POINTER(tfile->tun, NULL);
 728         }
 729         BUG_ON(tun->numqueues != 0);
 730
 731         synchronize_net();
 732         for (i = 0; i < n; i++) {
 733                 tfile = rtnl_dereference(tun->tfiles[i]);
 734                 tun_napi_del(tfile);
 735                 /* Drop read queue */
 736                 tun_queue_purge(tfile);
 737                 xdp_rxq_info_unreg(&tfile->xdp_rxq);
 738                 sock_put(&tfile->sk);
 739         }
 740         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 741                 tun_napi_del(tfile);
 742                 tun_enable_queue(tfile);
 743                 tun_queue_purge(tfile);
 744                 xdp_rxq_info_unreg(&tfile->xdp_rxq);
 745                 sock_put(&tfile->sk);
 746         }
 747         BUG_ON(tun->numdisabled != 0);
 748
 749         if (tun->flags & IFF_PERSIST)
 750                 module_put(THIS_MODULE);
 751 }
 752
 753 static int tun_attach(struct tun_struct *tun, struct file *file,
 754                       bool skip_filter, bool napi, bool napi_frags,
 755                       bool publish_tun)
 756 {
 757         struct tun_file *tfile = file->private_data;
 758         struct net_device *dev = tun->dev;
 759         int err;
 760
 761         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 762         if (err < 0)
 763                 goto out;
 764
 765         err = -EINVAL;
 766         if (rtnl_dereference(tfile->tun) && !tfile->detached)
 767                 goto out;
 768
 769         err = -EBUSY;
 770         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
 771                 goto out;
 772
 773         err = -E2BIG;
 774         if (!tfile->detached &&
 775             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 776                 goto out;
 777
 778         err = 0;
 779
 780         /* Re-attach the filter to persist device */
 781         if (!skip_filter && (tun->filter_attached == true)) {
 782                 lock_sock(tfile->socket.sk);
 783                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 784                 release_sock(tfile->socket.sk);
 785                 if (!err)
 786                         goto out;
 787         }
 788
 789         if (!tfile->detached &&
 790             ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
 791                             GFP_KERNEL, tun_ptr_free)) {
 792                 err = -ENOMEM;
 793                 goto out;
 794         }
 795
 796         tfile->queue_index = tun->numqueues;
 797         tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
 798
 799         if (tfile->detached) {
 800                 /* Re-attach detached tfile, updating XDP queue_index */
 801                 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
 802
 803                 if (tfile->xdp_rxq.queue_index    != tfile->queue_index)
 804                         tfile->xdp_rxq.queue_index = tfile->queue_index;
 805         } else {
 806                 /* Setup XDP RX-queue info, for new tfile getting attached */
 807                 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
 808                                        tun->dev, tfile->queue_index, 0);
 809                 if (err < 0)
 810                         goto out;
 811                 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
 812                                                  MEM_TYPE_PAGE_SHARED, NULL);
 813                 if (err < 0) {
 814                         xdp_rxq_info_unreg(&tfile->xdp_rxq);
 815                         goto out;
 816                 }
 817                 err = 0;
 818         }
 819
 820         if (tfile->detached) {
 821                 tun_enable_queue(tfile);
 822                 tun_napi_enable(tfile);
 823         } else {
 824                 sock_hold(&tfile->sk);
 825                 tun_napi_init(tun, tfile, napi, napi_frags);
 826         }
 827
 828         if (rtnl_dereference(tun->xdp_prog))
 829                 sock_set_flag(&tfile->sk, SOCK_XDP);
 830
 831         /* device is allowed to go away first, so no need to hold extra
 832          * refcnt.
 833          */
 834
 835         /* Publish tfile->tun and tun->tfiles only after we've fully
 836          * initialized tfile; otherwise we risk using half-initialized
 837          * object.
 838          */
 839         if (publish_tun)
 840                 rcu_assign_pointer(tfile->tun, tun);
 841         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 842         tun->numqueues++;
 843         tun_set_real_num_queues(tun);
 844 out:
 845         return err;
 846 }
 847
 848 static struct tun_struct *tun_get(struct tun_file *tfile)
 849 {
 850         struct tun_struct *tun;
 851
 852         rcu_read_lock();
 853         tun = rcu_dereference(tfile->tun);
 854         if (tun)
 855                 dev_hold(tun->dev);
 856         rcu_read_unlock();
 857
 858         return tun;
 859 }
 860
 861 static void tun_put(struct tun_struct *tun)
 862 {
 863         dev_put(tun->dev);
 864 }
 865
 866 /* TAP filtering */
 867 static void addr_hash_set(u32 *mask, const u8 *addr)
 868 {
 869         int n = ether_crc(ETH_ALEN, addr) >> 26;
 870         mask[n >> 5] |= (1 << (n & 31));
 871 }
 872
 873 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 874 {
 875         int n = ether_crc(ETH_ALEN, addr) >> 26;
 876         return mask[n >> 5] & (1 << (n & 31));
 877 }
 878
 879 static int update_filter(struct tap_filter *filter, void __user *arg)
 880 {
 881         struct { u8 u[ETH_ALEN]; } *addr;
 882         struct tun_filter uf;
 883         int err, alen, n, nexact;
 884
 885         if (copy_from_user(&uf, arg, sizeof(uf)))
 886                 return -EFAULT;
 887
 888         if (!uf.count) {
 889                 /* Disabled */
 890                 filter->count = 0;
 891                 return 0;
 892         }
 893
 894         alen = ETH_ALEN * uf.count;
 895         addr = memdup_user(arg + sizeof(uf), alen);
 896         if (IS_ERR(addr))
 897                 return PTR_ERR(addr);
 898
 899         /* The filter is updated without holding any locks. Which is
 900          * perfectly safe. We disable it first and in the worst
 901          * case we'll accept a few undesired packets. */
 902         filter->count = 0;
 903         wmb();
 904
 905         /* Use first set of addresses as an exact filter */
 906         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 907                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 908
 909         nexact = n;
 910
 911         /* Remaining multicast addresses are hashed,
 912          * unicast will leave the filter disabled. */
 913         memset(filter->mask, 0, sizeof(filter->mask));
 914         for (; n < uf.count; n++) {
 915                 if (!is_multicast_ether_addr(addr[n].u)) {
 916                         err = 0; /* no filter */
 917                         goto free_addr;
 918                 }
 919                 addr_hash_set(filter->mask, addr[n].u);
 920         }
 921
 922         /* For ALLMULTI just set the mask to all ones.
 923          * This overrides the mask populated above. */
 924         if ((uf.flags & TUN_FLT_ALLMULTI))
 925                 memset(filter->mask, ~0, sizeof(filter->mask));
 926
 927         /* Now enable the filter */
 928         wmb();
 929         filter->count = nexact;
 930
 931         /* Return the number of exact filters */
 932         err = nexact;
 933 free_addr:
 934         kfree(addr);
 935         return err;
 936 }
 937
 938 /* Returns: 0 - drop, !=0 - accept */
 939 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 940 {
 941         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 942          * at this point. */
 943         struct ethhdr *eh = (struct ethhdr *) skb->data;
 944         int i;
 945
 946         /* Exact match */
 947         for (i = 0; i < filter->count; i++)
 948                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 949                         return 1;
 950
 951         /* Inexact match (multicast only) */
 952         if (is_multicast_ether_addr(eh->h_dest))
 953                 return addr_hash_test(filter->mask, eh->h_dest);
 954
 955         return 0;
 956 }
 957
 958 /*
 959  * Checks whether the packet is accepted or not.
 960  * Returns: 0 - drop, !=0 - accept
 961  */
 962 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 963 {
 964         if (!filter->count)
 965                 return 1;
 966
 967         return run_filter(filter, skb);
 968 }
 969
 970 /* Network device part of the driver */
 971
 972 static const struct ethtool_ops tun_ethtool_ops;
 973
 974 static int tun_net_init(struct net_device *dev)
 975 {
 976         struct tun_struct *tun = netdev_priv(dev);
 977         struct ifreq *ifr = tun->ifr;
 978         int err;
 979
 980         dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
 981         if (!dev->tstats)
 982                 return -ENOMEM;
 983
 984         spin_lock_init(&tun->lock);
 985
 986         err = security_tun_dev_alloc_security(&tun->security);
 987         if (err < 0) {
 988                 free_percpu(dev->tstats);
 989                 return err;
 990         }
 991
 992         tun_flow_init(tun);
 993
 994         dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
 995                            TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
 996                            NETIF_F_HW_VLAN_STAG_TX;
 997         dev->features = dev->hw_features | NETIF_F_LLTX;
 998         dev->vlan_features = dev->features &
 999                              ~(NETIF_F_HW_VLAN_CTAG_TX |
1000                                NETIF_F_HW_VLAN_STAG_TX);
1001
1002         tun->flags = (tun->flags & ~TUN_FEATURES) |
1003                       (ifr->ifr_flags & TUN_FEATURES);
1004
1005         INIT_LIST_HEAD(&tun->disabled);
1006         err = tun_attach(tun, tun->file, false, ifr->ifr_flags & IFF_NAPI,
1007                          ifr->ifr_flags & IFF_NAPI_FRAGS, false);
1008         if (err < 0) {
1009                 tun_flow_uninit(tun);
1010                 security_tun_dev_free_security(tun->security);
1011                 free_percpu(dev->tstats);
1012                 return err;
1013         }
1014         return 0;
1015 }
1016
1017 /* Net device detach from fd. */
1018 static void tun_net_uninit(struct net_device *dev)
1019 {
1020         tun_detach_all(dev);
1021 }
1022
1023 /* Net device open. */
1024 static int tun_net_open(struct net_device *dev)
1025 {
1026         netif_tx_start_all_queues(dev);
1027
1028         return 0;
1029 }
1030
1031 /* Net device close. */
1032 static int tun_net_close(struct net_device *dev)
1033 {
1034         netif_tx_stop_all_queues(dev);
1035         return 0;
1036 }
1037
1038 /* Net device start xmit */
1039 static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1040 {
1041 #ifdef CONFIG_RPS
1042         if (tun->numqueues == 1 && static_branch_unlikely(&rps_needed)) {
1043                 /* Select queue was not called for the skbuff, so we extract the
1044                  * RPS hash and save it into the flow_table here.
1045                  */
1046                 struct tun_flow_entry *e;
1047                 __u32 rxhash;
1048
1049                 rxhash = __skb_get_hash_symmetric(skb);
1050                 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
1051                 if (e)
1052                         tun_flow_save_rps_rxhash(e, rxhash);
1053         }
1054 #endif
1055 }
1056
1057 static unsigned int run_ebpf_filter(struct tun_struct *tun,
1058                                     struct sk_buff *skb,
1059                                     int len)
1060 {
1061         struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1062
1063         if (prog)
1064                 len = bpf_prog_run_clear_cb(prog->prog, skb);
1065
1066         return len;
1067 }
1068
1069 /* Net device start xmit */
1070 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1071 {
1072         struct tun_struct *tun = netdev_priv(dev);
1073         enum skb_drop_reason drop_reason;
1074         int txq = skb->queue_mapping;
1075         struct netdev_queue *queue;
1076         struct tun_file *tfile;
1077         int len = skb->len;
1078
1079         rcu_read_lock();
1080         tfile = rcu_dereference(tun->tfiles[txq]);
1081
1082         /* Drop packet if interface is not attached */
1083         if (!tfile) {
1084                 drop_reason = SKB_DROP_REASON_DEV_READY;
1085                 goto drop;
1086         }
1087
1088         if (!rcu_dereference(tun->steering_prog))
1089                 tun_automq_xmit(tun, skb);
1090
1091         netif_info(tun, tx_queued, tun->dev, "%s %d\n", __func__, skb->len);
1092
1093         /* Drop if the filter does not like it.
1094          * This is a noop if the filter is disabled.
1095          * Filter can be enabled only for the TAP devices. */
1096         if (!check_filter(&tun->txflt, skb)) {
1097                 drop_reason = SKB_DROP_REASON_TAP_TXFILTER;
1098                 goto drop;
1099         }
1100
1101         if (tfile->socket.sk->sk_filter &&
1102             sk_filter(tfile->socket.sk, skb)) {
1103                 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
1104                 goto drop;
1105         }
1106
1107         len = run_ebpf_filter(tun, skb, len);
1108         if (len == 0) {
1109                 drop_reason = SKB_DROP_REASON_TAP_FILTER;
1110                 goto drop;
1111         }
1112
1113         if (pskb_trim(skb, len)) {
1114                 drop_reason = SKB_DROP_REASON_NOMEM;
1115                 goto drop;
1116         }
1117
1118         if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) {
1119                 drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
1120                 goto drop;
1121         }
1122
1123         skb_tx_timestamp(skb);
1124
1125         /* Orphan the skb - required as we might hang on to it
1126          * for indefinite time.
1127          */
1128         skb_orphan(skb);
1129
1130         nf_reset_ct(skb);
1131
1132         if (ptr_ring_produce(&tfile->tx_ring, skb)) {
1133                 drop_reason = SKB_DROP_REASON_FULL_RING;
1134                 goto drop;
1135         }
1136
1137         /* NETIF_F_LLTX requires to do our own update of trans_start */
1138         queue = netdev_get_tx_queue(dev, txq);
1139         txq_trans_cond_update(queue);
1140
1141         /* Notify and wake up reader process */
1142         if (tfile->flags & TUN_FASYNC)
1143                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1144         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1145
1146         rcu_read_unlock();
1147         return NETDEV_TX_OK;
1148
1149 drop:
1150         dev_core_stats_tx_dropped_inc(dev);
1151         skb_tx_error(skb);
1152         kfree_skb_reason(skb, drop_reason);
1153         rcu_read_unlock();
1154         return NET_XMIT_DROP;
1155 }
1156
1157 static void tun_net_mclist(struct net_device *dev)
1158 {
1159         /*
1160          * This callback is supposed to deal with mc filter in
1161          * _rx_ path and has nothing to do with the _tx_ path.
1162          * In rx path we always accept everything userspace gives us.
1163          */
1164 }
1165
1166 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1167         netdev_features_t features)
1168 {
1169         struct tun_struct *tun = netdev_priv(dev);
1170
1171         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1172 }
1173
1174 static void tun_set_headroom(struct net_device *dev, int new_hr)
1175 {
1176         struct tun_struct *tun = netdev_priv(dev);
1177
1178         if (new_hr < NET_SKB_PAD)
1179                 new_hr = NET_SKB_PAD;
1180
1181         tun->align = new_hr;
1182 }
1183
1184 static void
1185 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1186 {
1187         struct tun_struct *tun = netdev_priv(dev);
1188
1189         dev_get_tstats64(dev, stats);
1190
1191         stats->rx_frame_errors +=
1192                 (unsigned long)atomic_long_read(&tun->rx_frame_errors);
1193 }
1194
1195 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1196                        struct netlink_ext_ack *extack)
1197 {
1198         struct tun_struct *tun = netdev_priv(dev);
1199         struct tun_file *tfile;
1200         struct bpf_prog *old_prog;
1201         int i;
1202
1203         old_prog = rtnl_dereference(tun->xdp_prog);
1204         rcu_assign_pointer(tun->xdp_prog, prog);
1205         if (old_prog)
1206                 bpf_prog_put(old_prog);
1207
1208         for (i = 0; i < tun->numqueues; i++) {
1209                 tfile = rtnl_dereference(tun->tfiles[i]);
1210                 if (prog)
1211                         sock_set_flag(&tfile->sk, SOCK_XDP);
1212                 else
1213                         sock_reset_flag(&tfile->sk, SOCK_XDP);
1214         }
1215         list_for_each_entry(tfile, &tun->disabled, next) {
1216                 if (prog)
1217                         sock_set_flag(&tfile->sk, SOCK_XDP);
1218                 else
1219                         sock_reset_flag(&tfile->sk, SOCK_XDP);
1220         }
1221
1222         return 0;
1223 }
1224
1225 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1226 {
1227         switch (xdp->command) {
1228         case XDP_SETUP_PROG:
1229                 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1230         default:
1231                 return -EINVAL;
1232         }
1233 }
1234
1235 static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1236 {
1237         if (new_carrier) {
1238                 struct tun_struct *tun = netdev_priv(dev);
1239
1240                 if (!tun->numqueues)
1241                         return -EPERM;
1242
1243                 netif_carrier_on(dev);
1244         } else {
1245                 netif_carrier_off(dev);
1246         }
1247         return 0;
1248 }
1249
1250 static const struct net_device_ops tun_netdev_ops = {
1251         .ndo_init               = tun_net_init,
1252         .ndo_uninit             = tun_net_uninit,
1253         .ndo_open               = tun_net_open,
1254         .ndo_stop               = tun_net_close,
1255         .ndo_start_xmit         = tun_net_xmit,
1256         .ndo_fix_features       = tun_net_fix_features,
1257         .ndo_select_queue       = tun_select_queue,
1258         .ndo_set_rx_headroom    = tun_set_headroom,
1259         .ndo_get_stats64        = tun_net_get_stats64,
1260         .ndo_change_carrier     = tun_net_change_carrier,
1261 };
1262
1263 static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1264 {
1265         /* Notify and wake up reader process */
1266         if (tfile->flags & TUN_FASYNC)
1267                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1268         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1269 }
1270
1271 static int tun_xdp_xmit(struct net_device *dev, int n,
1272                         struct xdp_frame **frames, u32 flags)
1273 {
1274         struct tun_struct *tun = netdev_priv(dev);
1275         struct tun_file *tfile;
1276         u32 numqueues;
1277         int nxmit = 0;
1278         int i;
1279
1280         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1281                 return -EINVAL;
1282
1283         rcu_read_lock();
1284
1285 resample:
1286         numqueues = READ_ONCE(tun->numqueues);
1287         if (!numqueues) {
1288                 rcu_read_unlock();
1289                 return -ENXIO; /* Caller will free/return all frames */
1290         }
1291
1292         tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1293                                             numqueues]);
1294         if (unlikely(!tfile))
1295                 goto resample;
1296
1297         spin_lock(&tfile->tx_ring.producer_lock);
1298         for (i = 0; i < n; i++) {
1299                 struct xdp_frame *xdp = frames[i];
1300                 /* Encode the XDP flag into lowest bit for consumer to differ
1301                  * XDP buffer from sk_buff.
1302                  */
1303                 void *frame = tun_xdp_to_ptr(xdp);
1304
1305                 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1306                         dev_core_stats_tx_dropped_inc(dev);
1307                         break;
1308                 }
1309                 nxmit++;
1310         }
1311         spin_unlock(&tfile->tx_ring.producer_lock);
1312
1313         if (flags & XDP_XMIT_FLUSH)
1314                 __tun_xdp_flush_tfile(tfile);
1315
1316         rcu_read_unlock();
1317         return nxmit;
1318 }
1319
1320 static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1321 {
1322         struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
1323         int nxmit;
1324
1325         if (unlikely(!frame))
1326                 return -EOVERFLOW;
1327
1328         nxmit = tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1329         if (!nxmit)
1330                 xdp_return_frame_rx_napi(frame);
1331         return nxmit;
1332 }
1333
1334 static const struct net_device_ops tap_netdev_ops = {
1335         .ndo_init               = tun_net_init,
1336         .ndo_uninit             = tun_net_uninit,
1337         .ndo_open               = tun_net_open,
1338         .ndo_stop               = tun_net_close,
1339         .ndo_start_xmit         = tun_net_xmit,
1340         .ndo_fix_features       = tun_net_fix_features,
1341         .ndo_set_rx_mode        = tun_net_mclist,
1342         .ndo_set_mac_address    = eth_mac_addr,
1343         .ndo_validate_addr      = eth_validate_addr,
1344         .ndo_select_queue       = tun_select_queue,
1345         .ndo_features_check     = passthru_features_check,
1346         .ndo_set_rx_headroom    = tun_set_headroom,
1347         .ndo_get_stats64        = dev_get_tstats64,
1348         .ndo_bpf                = tun_xdp,
1349         .ndo_xdp_xmit           = tun_xdp_xmit,
1350         .ndo_change_carrier     = tun_net_change_carrier,
1351 };
1352
1353 static void tun_flow_init(struct tun_struct *tun)
1354 {
1355         int i;
1356
1357         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1358                 INIT_HLIST_HEAD(&tun->flows[i]);
1359
1360         tun->ageing_time = TUN_FLOW_EXPIRE;
1361         timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1362         mod_timer(&tun->flow_gc_timer,
1363                   round_jiffies_up(jiffies + tun->ageing_time));
1364 }
1365
1366 static void tun_flow_uninit(struct tun_struct *tun)
1367 {
1368         del_timer_sync(&tun->flow_gc_timer);
1369         tun_flow_flush(tun);
1370 }
1371
1372 #define MIN_MTU 68
1373 #define MAX_MTU 65535
1374
1375 /* Initialize net device. */
1376 static void tun_net_initialize(struct net_device *dev)
1377 {
1378         struct tun_struct *tun = netdev_priv(dev);
1379
1380         switch (tun->flags & TUN_TYPE_MASK) {
1381         case IFF_TUN:
1382                 dev->netdev_ops = &tun_netdev_ops;
1383                 dev->header_ops = &ip_tunnel_header_ops;
1384
1385                 /* Point-to-Point TUN Device */
1386                 dev->hard_header_len = 0;
1387                 dev->addr_len = 0;
1388                 dev->mtu = 1500;
1389
1390                 /* Zero header length */
1391                 dev->type = ARPHRD_NONE;
1392                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1393                 break;
1394
1395         case IFF_TAP:
1396                 dev->netdev_ops = &tap_netdev_ops;
1397                 /* Ethernet TAP Device */
1398                 ether_setup(dev);
1399                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1400                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1401
1402                 eth_hw_addr_random(dev);
1403
1404                 /* Currently tun does not support XDP, only tap does. */
1405                 dev->xdp_features = NETDEV_XDP_ACT_BASIC |
1406                                     NETDEV_XDP_ACT_REDIRECT |
1407                                     NETDEV_XDP_ACT_NDO_XMIT;
1408
1409                 break;
1410         }
1411
1412         dev->min_mtu = MIN_MTU;
1413         dev->max_mtu = MAX_MTU - dev->hard_header_len;
1414 }
1415
1416 static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1417 {
1418         struct sock *sk = tfile->socket.sk;
1419
1420         return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1421 }
1422
1423 /* Character device part */
1424
1425 /* Poll */
1426 static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1427 {
1428         struct tun_file *tfile = file->private_data;
1429         struct tun_struct *tun = tun_get(tfile);
1430         struct sock *sk;
1431         __poll_t mask = 0;
1432
1433         if (!tun)
1434                 return EPOLLERR;
1435
1436         sk = tfile->socket.sk;
1437
1438         poll_wait(file, sk_sleep(sk), wait);
1439
1440         if (!ptr_ring_empty(&tfile->tx_ring))
1441                 mask |= EPOLLIN | EPOLLRDNORM;
1442
1443         /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1444          * guarantee EPOLLOUT to be raised by either here or
1445          * tun_sock_write_space(). Then process could get notification
1446          * after it writes to a down device and meets -EIO.
1447          */
1448         if (tun_sock_writeable(tun, tfile) ||
1449             (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1450              tun_sock_writeable(tun, tfile)))
1451                 mask |= EPOLLOUT | EPOLLWRNORM;
1452
1453         if (tun->dev->reg_state != NETREG_REGISTERED)
1454                 mask = EPOLLERR;
1455
1456         tun_put(tun);
1457         return mask;
1458 }
1459
1460 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1461                                             size_t len,
1462                                             const struct iov_iter *it)
1463 {
1464         struct sk_buff *skb;
1465         size_t linear;
1466         int err;
1467         int i;
1468
1469         if (it->nr_segs > MAX_SKB_FRAGS + 1 ||
1470             len > (ETH_MAX_MTU - NET_SKB_PAD - NET_IP_ALIGN))
1471                 return ERR_PTR(-EMSGSIZE);
1472
1473         local_bh_disable();
1474         skb = napi_get_frags(&tfile->napi);
1475         local_bh_enable();
1476         if (!skb)
1477                 return ERR_PTR(-ENOMEM);
1478
1479         linear = iov_iter_single_seg_count(it);
1480         err = __skb_grow(skb, linear);
1481         if (err)
1482                 goto free;
1483
1484         skb->len = len;
1485         skb->data_len = len - linear;
1486         skb->truesize += skb->data_len;
1487
1488         for (i = 1; i < it->nr_segs; i++) {
1489                 const struct iovec *iov = iter_iov(it);
1490                 size_t fragsz = iov->iov_len;
1491                 struct page *page;
1492                 void *frag;
1493
1494                 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1495                         err = -EINVAL;
1496                         goto free;
1497                 }
1498                 frag = netdev_alloc_frag(fragsz);
1499                 if (!frag) {
1500                         err = -ENOMEM;
1501                         goto free;
1502                 }
1503                 page = virt_to_head_page(frag);
1504                 skb_fill_page_desc(skb, i - 1, page,
1505                                    frag - page_address(page), fragsz);
1506         }
1507
1508         return skb;
1509 free:
1510         /* frees skb and all frags allocated with napi_alloc_frag() */
1511         napi_free_frags(&tfile->napi);
1512         return ERR_PTR(err);
1513 }
1514
1515 /* prepad is the amount to reserve at front.  len is length after that.
1516  * linear is a hint as to how much to copy (usually headers). */
1517 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1518                                      size_t prepad, size_t len,
1519                                      size_t linear, int noblock)
1520 {
1521         struct sock *sk = tfile->socket.sk;
1522         struct sk_buff *skb;
1523         int err;
1524
1525         /* Under a page?  Don't bother with paged skb. */
1526         if (prepad + len < PAGE_SIZE || !linear)
1527                 linear = len;
1528
1529         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1530                                    &err, 0);
1531         if (!skb)
1532                 return ERR_PTR(err);
1533
1534         skb_reserve(skb, prepad);
1535         skb_put(skb, linear);
1536         skb->data_len = len - linear;
1537         skb->len += len - linear;
1538
1539         return skb;
1540 }
1541
1542 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1543                            struct sk_buff *skb, int more)
1544 {
1545         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1546         struct sk_buff_head process_queue;
1547         u32 rx_batched = tun->rx_batched;
1548         bool rcv = false;
1549
1550         if (!rx_batched || (!more && skb_queue_empty(queue))) {
1551                 local_bh_disable();
1552                 skb_record_rx_queue(skb, tfile->queue_index);
1553                 netif_receive_skb(skb);
1554                 local_bh_enable();
1555                 return;
1556         }
1557
1558         spin_lock(&queue->lock);
1559         if (!more || skb_queue_len(queue) == rx_batched) {
1560                 __skb_queue_head_init(&process_queue);
1561                 skb_queue_splice_tail_init(queue, &process_queue);
1562                 rcv = true;
1563         } else {
1564                 __skb_queue_tail(queue, skb);
1565         }
1566         spin_unlock(&queue->lock);
1567
1568         if (rcv) {
1569                 struct sk_buff *nskb;
1570
1571                 local_bh_disable();
1572                 while ((nskb = __skb_dequeue(&process_queue))) {
1573                         skb_record_rx_queue(nskb, tfile->queue_index);
1574                         netif_receive_skb(nskb);
1575                 }
1576                 skb_record_rx_queue(skb, tfile->queue_index);
1577                 netif_receive_skb(skb);
1578                 local_bh_enable();
1579         }
1580 }
1581
1582 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1583                               int len, int noblock, bool zerocopy)
1584 {
1585         if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1586                 return false;
1587
1588         if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1589                 return false;
1590
1591         if (!noblock)
1592                 return false;
1593
1594         if (zerocopy)
1595                 return false;
1596
1597         if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1598             SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1599                 return false;
1600
1601         return true;
1602 }
1603
1604 static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
1605                                        struct page_frag *alloc_frag, char *buf,
1606                                        int buflen, int len, int pad)
1607 {
1608         struct sk_buff *skb = build_skb(buf, buflen);
1609
1610         if (!skb)
1611                 return ERR_PTR(-ENOMEM);
1612
1613         skb_reserve(skb, pad);
1614         skb_put(skb, len);
1615         skb_set_owner_w(skb, tfile->socket.sk);
1616
1617         get_page(alloc_frag->page);
1618         alloc_frag->offset += buflen;
1619
1620         return skb;
1621 }
1622
1623 static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1624                        struct xdp_buff *xdp, u32 act)
1625 {
1626         int err;
1627
1628         switch (act) {
1629         case XDP_REDIRECT:
1630                 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1631                 if (err)
1632                         return err;
1633                 break;
1634         case XDP_TX:
1635                 err = tun_xdp_tx(tun->dev, xdp);
1636                 if (err < 0)
1637                         return err;
1638                 break;
1639         case XDP_PASS:
1640                 break;
1641         default:
1642                 bpf_warn_invalid_xdp_action(tun->dev, xdp_prog, act);
1643                 fallthrough;
1644         case XDP_ABORTED:
1645                 trace_xdp_exception(tun->dev, xdp_prog, act);
1646                 fallthrough;
1647         case XDP_DROP:
1648                 dev_core_stats_rx_dropped_inc(tun->dev);
1649                 break;
1650         }
1651
1652         return act;
1653 }
1654
1655 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1656                                      struct tun_file *tfile,
1657                                      struct iov_iter *from,
1658                                      struct virtio_net_hdr *hdr,
1659                                      int len, int *skb_xdp)
1660 {
1661         struct page_frag *alloc_frag = &current->task_frag;
1662         struct bpf_prog *xdp_prog;
1663         int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1664         char *buf;
1665         size_t copied;
1666         int pad = TUN_RX_PAD;
1667         int err = 0;
1668
1669         rcu_read_lock();
1670         xdp_prog = rcu_dereference(tun->xdp_prog);
1671         if (xdp_prog)
1672                 pad += XDP_PACKET_HEADROOM;
1673         buflen += SKB_DATA_ALIGN(len + pad);
1674         rcu_read_unlock();
1675
1676         alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1677         if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1678                 return ERR_PTR(-ENOMEM);
1679
1680         buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1681         copied = copy_page_from_iter(alloc_frag->page,
1682                                      alloc_frag->offset + pad,
1683                                      len, from);
1684         if (copied != len)
1685                 return ERR_PTR(-EFAULT);
1686
1687         /* There's a small window that XDP may be set after the check
1688          * of xdp_prog above, this should be rare and for simplicity
1689          * we do XDP on skb in case the headroom is not enough.
1690          */
1691         if (hdr->gso_type || !xdp_prog) {
1692                 *skb_xdp = 1;
1693                 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len,
1694                                        pad);
1695         }
1696
1697         *skb_xdp = 0;
1698
1699         local_bh_disable();
1700         rcu_read_lock();
1701         xdp_prog = rcu_dereference(tun->xdp_prog);
1702         if (xdp_prog) {
1703                 struct xdp_buff xdp;
1704                 u32 act;
1705
1706                 xdp_init_buff(&xdp, buflen, &tfile->xdp_rxq);
1707                 xdp_prepare_buff(&xdp, buf, pad, len, false);
1708
1709                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1710                 if (act == XDP_REDIRECT || act == XDP_TX) {
1711                         get_page(alloc_frag->page);
1712                         alloc_frag->offset += buflen;
1713                 }
1714                 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1715                 if (err < 0) {
1716                         if (act == XDP_REDIRECT || act == XDP_TX)
1717                                 put_page(alloc_frag->page);
1718                         goto out;
1719                 }
1720
1721                 if (err == XDP_REDIRECT)
1722                         xdp_do_flush();
1723                 if (err != XDP_PASS)
1724                         goto out;
1725
1726                 pad = xdp.data - xdp.data_hard_start;
1727                 len = xdp.data_end - xdp.data;
1728         }
1729         rcu_read_unlock();
1730         local_bh_enable();
1731
1732         return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1733
1734 out:
1735         rcu_read_unlock();
1736         local_bh_enable();
1737         return NULL;
1738 }
1739
1740 /* Get packet from user space buffer */
1741 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1742                             void *msg_control, struct iov_iter *from,
1743                             int noblock, bool more)
1744 {
1745         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1746         struct sk_buff *skb;
1747         size_t total_len = iov_iter_count(from);
1748         size_t len = total_len, align = tun->align, linear;
1749         struct virtio_net_hdr gso = { 0 };
1750         int good_linear;
1751         int copylen;
1752         bool zerocopy = false;
1753         int err;
1754         u32 rxhash = 0;
1755         int skb_xdp = 1;
1756         bool frags = tun_napi_frags_enabled(tfile);
1757         enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
1758
1759         if (!(tun->flags & IFF_NO_PI)) {
1760                 if (len < sizeof(pi))
1761                         return -EINVAL;
1762                 len -= sizeof(pi);
1763
1764                 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1765                         return -EFAULT;
1766         }
1767
1768         if (tun->flags & IFF_VNET_HDR) {
1769                 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1770
1771                 if (len < vnet_hdr_sz)
1772                         return -EINVAL;
1773                 len -= vnet_hdr_sz;
1774
1775                 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1776                         return -EFAULT;
1777
1778                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1779                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1780                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1781
1782                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1783                         return -EINVAL;
1784                 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1785         }
1786
1787         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1788                 align += NET_IP_ALIGN;
1789                 if (unlikely(len < ETH_HLEN ||
1790                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1791                         return -EINVAL;
1792         }
1793
1794         good_linear = SKB_MAX_HEAD(align);
1795
1796         if (msg_control) {
1797                 struct iov_iter i = *from;
1798
1799                 /* There are 256 bytes to be copied in skb, so there is
1800                  * enough room for skb expand head in case it is used.
1801                  * The rest of the buffer is mapped from userspace.
1802                  */
1803                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1804                 if (copylen > good_linear)
1805                         copylen = good_linear;
1806                 linear = copylen;
1807                 iov_iter_advance(&i, copylen);
1808                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1809                         zerocopy = true;
1810         }
1811
1812         if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1813                 /* For the packet that is not easy to be processed
1814                  * (e.g gso or jumbo packet), we will do it at after
1815                  * skb was created with generic XDP routine.
1816                  */
1817                 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1818                 err = PTR_ERR_OR_ZERO(skb);
1819                 if (err)
1820                         goto drop;
1821                 if (!skb)
1822                         return total_len;
1823         } else {
1824                 if (!zerocopy) {
1825                         copylen = len;
1826                         if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1827                                 linear = good_linear;
1828                         else
1829                                 linear = tun16_to_cpu(tun, gso.hdr_len);
1830                 }
1831
1832                 if (frags) {
1833                         mutex_lock(&tfile->napi_mutex);
1834                         skb = tun_napi_alloc_frags(tfile, copylen, from);
1835                         /* tun_napi_alloc_frags() enforces a layout for the skb.
1836                          * If zerocopy is enabled, then this layout will be
1837                          * overwritten by zerocopy_sg_from_iter().
1838                          */
1839                         zerocopy = false;
1840                 } else {
1841                         skb = tun_alloc_skb(tfile, align, copylen, linear,
1842                                             noblock);
1843                 }
1844
1845                 err = PTR_ERR_OR_ZERO(skb);
1846                 if (err)
1847                         goto drop;
1848
1849                 if (zerocopy)
1850                         err = zerocopy_sg_from_iter(skb, from);
1851                 else
1852                         err = skb_copy_datagram_from_iter(skb, 0, from, len);
1853
1854                 if (err) {
1855                         err = -EFAULT;
1856                         drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
1857                         goto drop;
1858                 }
1859         }
1860
1861         if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1862                 atomic_long_inc(&tun->rx_frame_errors);
1863                 err = -EINVAL;
1864                 goto free_skb;
1865         }
1866
1867         switch (tun->flags & TUN_TYPE_MASK) {
1868         case IFF_TUN:
1869                 if (tun->flags & IFF_NO_PI) {
1870                         u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1871
1872                         switch (ip_version) {
1873                         case 4:
1874                                 pi.proto = htons(ETH_P_IP);
1875                                 break;
1876                         case 6:
1877                                 pi.proto = htons(ETH_P_IPV6);
1878                                 break;
1879                         default:
1880                                 err = -EINVAL;
1881                                 goto drop;
1882                         }
1883                 }
1884
1885                 skb_reset_mac_header(skb);
1886                 skb->protocol = pi.proto;
1887                 skb->dev = tun->dev;
1888                 break;
1889         case IFF_TAP:
1890                 if (frags && !pskb_may_pull(skb, ETH_HLEN)) {
1891                         err = -ENOMEM;
1892                         drop_reason = SKB_DROP_REASON_HDR_TRUNC;
1893                         goto drop;
1894                 }
1895                 skb->protocol = eth_type_trans(skb, tun->dev);
1896                 break;
1897         }
1898
1899         /* copy skb_ubuf_info for callback when skb has no error */
1900         if (zerocopy) {
1901                 skb_zcopy_init(skb, msg_control);
1902         } else if (msg_control) {
1903                 struct ubuf_info *uarg = msg_control;
1904                 uarg->callback(NULL, uarg, false);
1905         }
1906
1907         skb_reset_network_header(skb);
1908         skb_probe_transport_header(skb);
1909         skb_record_rx_queue(skb, tfile->queue_index);
1910
1911         if (skb_xdp) {
1912                 struct bpf_prog *xdp_prog;
1913                 int ret;
1914
1915                 local_bh_disable();
1916                 rcu_read_lock();
1917                 xdp_prog = rcu_dereference(tun->xdp_prog);
1918                 if (xdp_prog) {
1919                         ret = do_xdp_generic(xdp_prog, skb);
1920                         if (ret != XDP_PASS) {
1921                                 rcu_read_unlock();
1922                                 local_bh_enable();
1923                                 goto unlock_frags;
1924                         }
1925                 }
1926                 rcu_read_unlock();
1927                 local_bh_enable();
1928         }
1929
1930         /* Compute the costly rx hash only if needed for flow updates.
1931          * We may get a very small possibility of OOO during switching, not
1932          * worth to optimize.
1933          */
1934         if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1935             !tfile->detached)
1936                 rxhash = __skb_get_hash_symmetric(skb);
1937
1938         rcu_read_lock();
1939         if (unlikely(!(tun->dev->flags & IFF_UP))) {
1940                 err = -EIO;
1941                 rcu_read_unlock();
1942                 drop_reason = SKB_DROP_REASON_DEV_READY;
1943                 goto drop;
1944         }
1945
1946         if (frags) {
1947                 u32 headlen;
1948
1949                 /* Exercise flow dissector code path. */
1950                 skb_push(skb, ETH_HLEN);
1951                 headlen = eth_get_headlen(tun->dev, skb->data,
1952                                           skb_headlen(skb));
1953
1954                 if (unlikely(headlen > skb_headlen(skb))) {
1955                         WARN_ON_ONCE(1);
1956                         err = -ENOMEM;
1957                         dev_core_stats_rx_dropped_inc(tun->dev);
1958 napi_busy:
1959                         napi_free_frags(&tfile->napi);
1960                         rcu_read_unlock();
1961                         mutex_unlock(&tfile->napi_mutex);
1962                         return err;
1963                 }
1964
1965                 if (likely(napi_schedule_prep(&tfile->napi))) {
1966                         local_bh_disable();
1967                         napi_gro_frags(&tfile->napi);
1968                         napi_complete(&tfile->napi);
1969                         local_bh_enable();
1970                 } else {
1971                         err = -EBUSY;
1972                         goto napi_busy;
1973                 }
1974                 mutex_unlock(&tfile->napi_mutex);
1975         } else if (tfile->napi_enabled) {
1976                 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1977                 int queue_len;
1978
1979                 spin_lock_bh(&queue->lock);
1980                 __skb_queue_tail(queue, skb);
1981                 queue_len = skb_queue_len(queue);
1982                 spin_unlock(&queue->lock);
1983
1984                 if (!more || queue_len > NAPI_POLL_WEIGHT)
1985                         napi_schedule(&tfile->napi);
1986
1987                 local_bh_enable();
1988         } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1989                 tun_rx_batched(tun, tfile, skb, more);
1990         } else {
1991                 netif_rx(skb);
1992         }
1993         rcu_read_unlock();
1994
1995         preempt_disable();
1996         dev_sw_netstats_rx_add(tun->dev, len);
1997         preempt_enable();
1998
1999         if (rxhash)
2000                 tun_flow_update(tun, rxhash, tfile);
2001
2002         return total_len;
2003
2004 drop:
2005         if (err != -EAGAIN)
2006                 dev_core_stats_rx_dropped_inc(tun->dev);
2007
2008 free_skb:
2009         if (!IS_ERR_OR_NULL(skb))
2010                 kfree_skb_reason(skb, drop_reason);
2011
2012 unlock_frags:
2013         if (frags) {
2014                 tfile->napi.skb = NULL;
2015                 mutex_unlock(&tfile->napi_mutex);
2016         }
2017
2018         return err ?: total_len;
2019 }
2020
2021 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
2022 {
2023         struct file *file = iocb->ki_filp;
2024         struct tun_file *tfile = file->private_data;
2025         struct tun_struct *tun = tun_get(tfile);
2026         ssize_t result;
2027         int noblock = 0;
2028
2029         if (!tun)
2030                 return -EBADFD;
2031
2032         if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
2033                 noblock = 1;
2034
2035         result = tun_get_user(tun, tfile, NULL, from, noblock, false);
2036
2037         tun_put(tun);
2038         return result;
2039 }
2040
2041 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2042                                 struct tun_file *tfile,
2043                                 struct xdp_frame *xdp_frame,
2044                                 struct iov_iter *iter)
2045 {
2046         int vnet_hdr_sz = 0;
2047         size_t size = xdp_frame->len;
2048         size_t ret;
2049
2050         if (tun->flags & IFF_VNET_HDR) {
2051                 struct virtio_net_hdr gso = { 0 };
2052
2053                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2054                 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2055                         return -EINVAL;
2056                 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2057                              sizeof(gso)))
2058                         return -EFAULT;
2059                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2060         }
2061
2062         ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2063
2064         preempt_disable();
2065         dev_sw_netstats_tx_add(tun->dev, 1, ret);
2066         preempt_enable();
2067
2068         return ret;
2069 }
2070
2071 /* Put packet to the user space buffer */
2072 static ssize_t tun_put_user(struct tun_struct *tun,
2073                             struct tun_file *tfile,
2074                             struct sk_buff *skb,
2075                             struct iov_iter *iter)
2076 {
2077         struct tun_pi pi = { 0, skb->protocol };
2078         ssize_t total;
2079         int vlan_offset = 0;
2080         int vlan_hlen = 0;
2081         int vnet_hdr_sz = 0;
2082
2083         if (skb_vlan_tag_present(skb))
2084                 vlan_hlen = VLAN_HLEN;
2085
2086         if (tun->flags & IFF_VNET_HDR)
2087                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2088
2089         total = skb->len + vlan_hlen + vnet_hdr_sz;
2090
2091         if (!(tun->flags & IFF_NO_PI)) {
2092                 if (iov_iter_count(iter) < sizeof(pi))
2093                         return -EINVAL;
2094
2095                 total += sizeof(pi);
2096                 if (iov_iter_count(iter) < total) {
2097                         /* Packet will be striped */
2098                         pi.flags |= TUN_PKT_STRIP;
2099                 }
2100
2101                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2102                         return -EFAULT;
2103         }
2104
2105         if (vnet_hdr_sz) {
2106                 struct virtio_net_hdr gso;
2107
2108                 if (iov_iter_count(iter) < vnet_hdr_sz)
2109                         return -EINVAL;
2110
2111                 if (virtio_net_hdr_from_skb(skb, &gso,
2112                                             tun_is_little_endian(tun), true,
2113                                             vlan_hlen)) {
2114                         struct skb_shared_info *sinfo = skb_shinfo(skb);
2115                         pr_err("unexpected GSO type: "
2116                                "0x%x, gso_size %d, hdr_len %d\n",
2117                                sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2118                                tun16_to_cpu(tun, gso.hdr_len));
2119                         print_hex_dump(KERN_ERR, "tun: ",
2120                                        DUMP_PREFIX_NONE,
2121                                        16, 1, skb->head,
2122                                        min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2123                         WARN_ON_ONCE(1);
2124                         return -EINVAL;
2125                 }
2126
2127                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2128                         return -EFAULT;
2129
2130                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2131         }
2132
2133         if (vlan_hlen) {
2134                 int ret;
2135                 struct veth veth;
2136
2137                 veth.h_vlan_proto = skb->vlan_proto;
2138                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2139
2140                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2141
2142                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2143                 if (ret || !iov_iter_count(iter))
2144                         goto done;
2145
2146                 ret = copy_to_iter(&veth, sizeof(veth), iter);
2147                 if (ret != sizeof(veth) || !iov_iter_count(iter))
2148                         goto done;
2149         }
2150
2151         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2152
2153 done:
2154         /* caller is in process context, */
2155         preempt_disable();
2156         dev_sw_netstats_tx_add(tun->dev, 1, skb->len + vlan_hlen);
2157         preempt_enable();
2158
2159         return total;
2160 }
2161
2162 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2163 {
2164         DECLARE_WAITQUEUE(wait, current);
2165         void *ptr = NULL;
2166         int error = 0;
2167
2168         ptr = ptr_ring_consume(&tfile->tx_ring);
2169         if (ptr)
2170                 goto out;
2171         if (noblock) {
2172                 error = -EAGAIN;
2173                 goto out;
2174         }
2175
2176         add_wait_queue(&tfile->socket.wq.wait, &wait);
2177
2178         while (1) {
2179                 set_current_state(TASK_INTERRUPTIBLE);
2180                 ptr = ptr_ring_consume(&tfile->tx_ring);
2181                 if (ptr)
2182                         break;
2183                 if (signal_pending(current)) {
2184                         error = -ERESTARTSYS;
2185                         break;
2186                 }
2187                 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2188                         error = -EFAULT;
2189                         break;
2190                 }
2191
2192                 schedule();
2193         }
2194
2195         __set_current_state(TASK_RUNNING);
2196         remove_wait_queue(&tfile->socket.wq.wait, &wait);
2197
2198 out:
2199         *err = error;
2200         return ptr;
2201 }
2202
2203 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2204                            struct iov_iter *to,
2205                            int noblock, void *ptr)
2206 {
2207         ssize_t ret;
2208         int err;
2209
2210         if (!iov_iter_count(to)) {
2211                 tun_ptr_free(ptr);
2212                 return 0;
2213         }
2214
2215         if (!ptr) {
2216                 /* Read frames from ring */
2217                 ptr = tun_ring_recv(tfile, noblock, &err);
2218                 if (!ptr)
2219                         return err;
2220         }
2221
2222         if (tun_is_xdp_frame(ptr)) {
2223                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2224
2225                 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2226                 xdp_return_frame(xdpf);
2227         } else {
2228                 struct sk_buff *skb = ptr;
2229
2230                 ret = tun_put_user(tun, tfile, skb, to);
2231                 if (unlikely(ret < 0))
2232                         kfree_skb(skb);
2233                 else
2234                         consume_skb(skb);
2235         }
2236
2237         return ret;
2238 }
2239
2240 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2241 {
2242         struct file *file = iocb->ki_filp;
2243         struct tun_file *tfile = file->private_data;
2244         struct tun_struct *tun = tun_get(tfile);
2245         ssize_t len = iov_iter_count(to), ret;
2246         int noblock = 0;
2247
2248         if (!tun)
2249                 return -EBADFD;
2250
2251         if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
2252                 noblock = 1;
2253
2254         ret = tun_do_read(tun, tfile, to, noblock, NULL);
2255         ret = min_t(ssize_t, ret, len);
2256         if (ret > 0)
2257                 iocb->ki_pos = ret;
2258         tun_put(tun);
2259         return ret;
2260 }
2261
2262 static void tun_prog_free(struct rcu_head *rcu)
2263 {
2264         struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2265
2266         bpf_prog_destroy(prog->prog);
2267         kfree(prog);
2268 }
2269
2270 static int __tun_set_ebpf(struct tun_struct *tun,
2271                           struct tun_prog __rcu **prog_p,
2272                           struct bpf_prog *prog)
2273 {
2274         struct tun_prog *old, *new = NULL;
2275
2276         if (prog) {
2277                 new = kmalloc(sizeof(*new), GFP_KERNEL);
2278                 if (!new)
2279                         return -ENOMEM;
2280                 new->prog = prog;
2281         }
2282
2283         spin_lock_bh(&tun->lock);
2284         old = rcu_dereference_protected(*prog_p,
2285                                         lockdep_is_held(&tun->lock));
2286         rcu_assign_pointer(*prog_p, new);
2287         spin_unlock_bh(&tun->lock);
2288
2289         if (old)
2290                 call_rcu(&old->rcu, tun_prog_free);
2291
2292         return 0;
2293 }
2294
2295 static void tun_free_netdev(struct net_device *dev)
2296 {
2297         struct tun_struct *tun = netdev_priv(dev);
2298
2299         BUG_ON(!(list_empty(&tun->disabled)));
2300
2301         free_percpu(dev->tstats);
2302         tun_flow_uninit(tun);
2303         security_tun_dev_free_security(tun->security);
2304         __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2305         __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2306 }
2307
2308 static void tun_setup(struct net_device *dev)
2309 {
2310         struct tun_struct *tun = netdev_priv(dev);
2311
2312         tun->owner = INVALID_UID;
2313         tun->group = INVALID_GID;
2314         tun_default_link_ksettings(dev, &tun->link_ksettings);
2315
2316         dev->ethtool_ops = &tun_ethtool_ops;
2317         dev->needs_free_netdev = true;
2318         dev->priv_destructor = tun_free_netdev;
2319         /* We prefer our own queue length */
2320         dev->tx_queue_len = TUN_READQ_SIZE;
2321 }
2322
2323 /* Trivial set of netlink ops to allow deleting tun or tap
2324  * device with netlink.
2325  */
2326 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2327                         struct netlink_ext_ack *extack)
2328 {
2329         NL_SET_ERR_MSG(extack,
2330                        "tun/tap creation via rtnetlink is not supported.");
2331         return -EOPNOTSUPP;
2332 }
2333
2334 static size_t tun_get_size(const struct net_device *dev)
2335 {
2336         BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2337         BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2338
2339         return nla_total_size(sizeof(uid_t)) + /* OWNER */
2340                nla_total_size(sizeof(gid_t)) + /* GROUP */
2341                nla_total_size(sizeof(u8)) + /* TYPE */
2342                nla_total_size(sizeof(u8)) + /* PI */
2343                nla_total_size(sizeof(u8)) + /* VNET_HDR */
2344                nla_total_size(sizeof(u8)) + /* PERSIST */
2345                nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2346                nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2347                nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2348                0;
2349 }
2350
2351 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2352 {
2353         struct tun_struct *tun = netdev_priv(dev);
2354
2355         if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2356                 goto nla_put_failure;
2357         if (uid_valid(tun->owner) &&
2358             nla_put_u32(skb, IFLA_TUN_OWNER,
2359                         from_kuid_munged(current_user_ns(), tun->owner)))
2360                 goto nla_put_failure;
2361         if (gid_valid(tun->group) &&
2362             nla_put_u32(skb, IFLA_TUN_GROUP,
2363                         from_kgid_munged(current_user_ns(), tun->group)))
2364                 goto nla_put_failure;
2365         if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2366                 goto nla_put_failure;
2367         if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2368                 goto nla_put_failure;
2369         if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2370                 goto nla_put_failure;
2371         if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2372                        !!(tun->flags & IFF_MULTI_QUEUE)))
2373                 goto nla_put_failure;
2374         if (tun->flags & IFF_MULTI_QUEUE) {
2375                 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2376                         goto nla_put_failure;
2377                 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2378                                 tun->numdisabled))
2379                         goto nla_put_failure;
2380         }
2381
2382         return 0;
2383
2384 nla_put_failure:
2385         return -EMSGSIZE;
2386 }
2387
2388 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2389         .kind           = DRV_NAME,
2390         .priv_size      = sizeof(struct tun_struct),
2391         .setup          = tun_setup,
2392         .validate       = tun_validate,
2393         .get_size       = tun_get_size,
2394         .fill_info      = tun_fill_info,
2395 };
2396
2397 static void tun_sock_write_space(struct sock *sk)
2398 {
2399         struct tun_file *tfile;
2400         wait_queue_head_t *wqueue;
2401
2402         if (!sock_writeable(sk))
2403                 return;
2404
2405         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2406                 return;
2407
2408         wqueue = sk_sleep(sk);
2409         if (wqueue && waitqueue_active(wqueue))
2410                 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2411                                                 EPOLLWRNORM | EPOLLWRBAND);
2412
2413         tfile = container_of(sk, struct tun_file, sk);
2414         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2415 }
2416
2417 static void tun_put_page(struct tun_page *tpage)
2418 {
2419         if (tpage->page)
2420                 __page_frag_cache_drain(tpage->page, tpage->count);
2421 }
2422
2423 static int tun_xdp_one(struct tun_struct *tun,
2424                        struct tun_file *tfile,
2425                        struct xdp_buff *xdp, int *flush,
2426                        struct tun_page *tpage)
2427 {
2428         unsigned int datasize = xdp->data_end - xdp->data;
2429         struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2430         struct virtio_net_hdr *gso = &hdr->gso;
2431         struct bpf_prog *xdp_prog;
2432         struct sk_buff *skb = NULL;
2433         struct sk_buff_head *queue;
2434         u32 rxhash = 0, act;
2435         int buflen = hdr->buflen;
2436         int ret = 0;
2437         bool skb_xdp = false;
2438         struct page *page;
2439
2440         xdp_prog = rcu_dereference(tun->xdp_prog);
2441         if (xdp_prog) {
2442                 if (gso->gso_type) {
2443                         skb_xdp = true;
2444                         goto build;
2445                 }
2446
2447                 xdp_init_buff(xdp, buflen, &tfile->xdp_rxq);
2448                 xdp_set_data_meta_invalid(xdp);
2449
2450                 act = bpf_prog_run_xdp(xdp_prog, xdp);
2451                 ret = tun_xdp_act(tun, xdp_prog, xdp, act);
2452                 if (ret < 0) {
2453                         put_page(virt_to_head_page(xdp->data));
2454                         return ret;
2455                 }
2456
2457                 switch (ret) {
2458                 case XDP_REDIRECT:
2459                         *flush = true;
2460                         fallthrough;
2461                 case XDP_TX:
2462                         return 0;
2463                 case XDP_PASS:
2464                         break;
2465                 default:
2466                         page = virt_to_head_page(xdp->data);
2467                         if (tpage->page == page) {
2468                                 ++tpage->count;
2469                         } else {
2470                                 tun_put_page(tpage);
2471                                 tpage->page = page;
2472                                 tpage->count = 1;
2473                         }
2474                         return 0;
2475                 }
2476         }
2477
2478 build:
2479         skb = build_skb(xdp->data_hard_start, buflen);
2480         if (!skb) {
2481                 ret = -ENOMEM;
2482                 goto out;
2483         }
2484
2485         skb_reserve(skb, xdp->data - xdp->data_hard_start);
2486         skb_put(skb, xdp->data_end - xdp->data);
2487
2488         if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2489                 atomic_long_inc(&tun->rx_frame_errors);
2490                 kfree_skb(skb);
2491                 ret = -EINVAL;
2492                 goto out;
2493         }
2494
2495         skb->protocol = eth_type_trans(skb, tun->dev);
2496         skb_reset_network_header(skb);
2497         skb_probe_transport_header(skb);
2498         skb_record_rx_queue(skb, tfile->queue_index);
2499
2500         if (skb_xdp) {
2501                 ret = do_xdp_generic(xdp_prog, skb);
2502                 if (ret != XDP_PASS) {
2503                         ret = 0;
2504                         goto out;
2505                 }
2506         }
2507
2508         if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2509             !tfile->detached)
2510                 rxhash = __skb_get_hash_symmetric(skb);
2511
2512         if (tfile->napi_enabled) {
2513                 queue = &tfile->sk.sk_write_queue;
2514                 spin_lock(&queue->lock);
2515                 __skb_queue_tail(queue, skb);
2516                 spin_unlock(&queue->lock);
2517                 ret = 1;
2518         } else {
2519                 netif_receive_skb(skb);
2520                 ret = 0;
2521         }
2522
2523         /* No need to disable preemption here since this function is
2524          * always called with bh disabled
2525          */
2526         dev_sw_netstats_rx_add(tun->dev, datasize);
2527
2528         if (rxhash)
2529                 tun_flow_update(tun, rxhash, tfile);
2530
2531 out:
2532         return ret;
2533 }
2534
2535 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2536 {
2537         int ret, i;
2538         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2539         struct tun_struct *tun = tun_get(tfile);
2540         struct tun_msg_ctl *ctl = m->msg_control;
2541         struct xdp_buff *xdp;
2542
2543         if (!tun)
2544                 return -EBADFD;
2545
2546         if (m->msg_controllen == sizeof(struct tun_msg_ctl) &&
2547             ctl && ctl->type == TUN_MSG_PTR) {
2548                 struct tun_page tpage;
2549                 int n = ctl->num;
2550                 int flush = 0, queued = 0;
2551
2552                 memset(&tpage, 0, sizeof(tpage));
2553
2554                 local_bh_disable();
2555                 rcu_read_lock();
2556
2557                 for (i = 0; i < n; i++) {
2558                         xdp = &((struct xdp_buff *)ctl->ptr)[i];
2559                         ret = tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2560                         if (ret > 0)
2561                                 queued += ret;
2562                 }
2563
2564                 if (flush)
2565                         xdp_do_flush();
2566
2567                 if (tfile->napi_enabled && queued > 0)
2568                         napi_schedule(&tfile->napi);
2569
2570                 rcu_read_unlock();
2571                 local_bh_enable();
2572
2573                 tun_put_page(&tpage);
2574
2575                 ret = total_len;
2576                 goto out;
2577         }
2578
2579         ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2580                            m->msg_flags & MSG_DONTWAIT,
2581                            m->msg_flags & MSG_MORE);
2582 out:
2583         tun_put(tun);
2584         return ret;
2585 }
2586
2587 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2588                        int flags)
2589 {
2590         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2591         struct tun_struct *tun = tun_get(tfile);
2592         void *ptr = m->msg_control;
2593         int ret;
2594
2595         if (!tun) {
2596                 ret = -EBADFD;
2597                 goto out_free;
2598         }
2599
2600         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2601                 ret = -EINVAL;
2602                 goto out_put_tun;
2603         }
2604         if (flags & MSG_ERRQUEUE) {
2605                 ret = sock_recv_errqueue(sock->sk, m, total_len,
2606                                          SOL_PACKET, TUN_TX_TIMESTAMP);
2607                 goto out;
2608         }
2609         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2610         if (ret > (ssize_t)total_len) {
2611                 m->msg_flags |= MSG_TRUNC;
2612                 ret = flags & MSG_TRUNC ? ret : total_len;
2613         }
2614 out:
2615         tun_put(tun);
2616         return ret;
2617
2618 out_put_tun:
2619         tun_put(tun);
2620 out_free:
2621         tun_ptr_free(ptr);
2622         return ret;
2623 }
2624
2625 static int tun_ptr_peek_len(void *ptr)
2626 {
2627         if (likely(ptr)) {
2628                 if (tun_is_xdp_frame(ptr)) {
2629                         struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2630
2631                         return xdpf->len;
2632                 }
2633                 return __skb_array_len_with_tag(ptr);
2634         } else {
2635                 return 0;
2636         }
2637 }
2638
2639 static int tun_peek_len(struct socket *sock)
2640 {
2641         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2642         struct tun_struct *tun;
2643         int ret = 0;
2644
2645         tun = tun_get(tfile);
2646         if (!tun)
2647                 return 0;
2648
2649         ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2650         tun_put(tun);
2651
2652         return ret;
2653 }
2654
2655 /* Ops structure to mimic raw sockets with tun */
2656 static const struct proto_ops tun_socket_ops = {
2657         .peek_len = tun_peek_len,
2658         .sendmsg = tun_sendmsg,
2659         .recvmsg = tun_recvmsg,
2660 };
2661
2662 static struct proto tun_proto = {
2663         .name           = "tun",
2664         .owner          = THIS_MODULE,
2665         .obj_size       = sizeof(struct tun_file),
2666 };
2667
2668 static int tun_flags(struct tun_struct *tun)
2669 {
2670         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2671 }
2672
2673 static ssize_t tun_flags_show(struct device *dev, struct device_attribute *attr,
2674                               char *buf)
2675 {
2676         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2677         return sysfs_emit(buf, "0x%x\n", tun_flags(tun));
2678 }
2679
2680 static ssize_t owner_show(struct device *dev, struct device_attribute *attr,
2681                           char *buf)
2682 {
2683         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2684         return uid_valid(tun->owner)?
2685                 sysfs_emit(buf, "%u\n",
2686                            from_kuid_munged(current_user_ns(), tun->owner)) :
2687                 sysfs_emit(buf, "-1\n");
2688 }
2689
2690 static ssize_t group_show(struct device *dev, struct device_attribute *attr,
2691                           char *buf)
2692 {
2693         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2694         return gid_valid(tun->group) ?
2695                 sysfs_emit(buf, "%u\n",
2696                            from_kgid_munged(current_user_ns(), tun->group)) :
2697                 sysfs_emit(buf, "-1\n");
2698 }
2699
2700 static DEVICE_ATTR_RO(tun_flags);
2701 static DEVICE_ATTR_RO(owner);
2702 static DEVICE_ATTR_RO(group);
2703
2704 static struct attribute *tun_dev_attrs[] = {
2705         &dev_attr_tun_flags.attr,
2706         &dev_attr_owner.attr,
2707         &dev_attr_group.attr,
2708         NULL
2709 };
2710
2711 static const struct attribute_group tun_attr_group = {
2712         .attrs = tun_dev_attrs
2713 };
2714
2715 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2716 {
2717         struct tun_struct *tun;
2718         struct tun_file *tfile = file->private_data;
2719         struct net_device *dev;
2720         int err;
2721
2722         if (tfile->detached)
2723                 return -EINVAL;
2724
2725         if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2726                 if (!capable(CAP_NET_ADMIN))
2727                         return -EPERM;
2728
2729                 if (!(ifr->ifr_flags & IFF_NAPI) ||
2730                     (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2731                         return -EINVAL;
2732         }
2733
2734         dev = __dev_get_by_name(net, ifr->ifr_name);
2735         if (dev) {
2736                 if (ifr->ifr_flags & IFF_TUN_EXCL)
2737                         return -EBUSY;
2738                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2739                         tun = netdev_priv(dev);
2740                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2741                         tun = netdev_priv(dev);
2742                 else
2743                         return -EINVAL;
2744
2745                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2746                     !!(tun->flags & IFF_MULTI_QUEUE))
2747                         return -EINVAL;
2748
2749                 if (tun_not_capable(tun))
2750                         return -EPERM;
2751                 err = security_tun_dev_open(tun->security);
2752                 if (err < 0)
2753                         return err;
2754
2755                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2756                                  ifr->ifr_flags & IFF_NAPI,
2757                                  ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2758                 if (err < 0)
2759                         return err;
2760
2761                 if (tun->flags & IFF_MULTI_QUEUE &&
2762                     (tun->numqueues + tun->numdisabled > 1)) {
2763                         /* One or more queue has already been attached, no need
2764                          * to initialize the device again.
2765                          */
2766                         netdev_state_change(dev);
2767                         return 0;
2768                 }
2769
2770                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2771                               (ifr->ifr_flags & TUN_FEATURES);
2772
2773                 netdev_state_change(dev);
2774         } else {
2775                 char *name;
2776                 unsigned long flags = 0;
2777                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2778                              MAX_TAP_QUEUES : 1;
2779
2780                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2781                         return -EPERM;
2782                 err = security_tun_dev_create();
2783                 if (err < 0)
2784                         return err;
2785
2786                 /* Set dev type */
2787                 if (ifr->ifr_flags & IFF_TUN) {
2788                         /* TUN device */
2789                         flags |= IFF_TUN;
2790                         name = "tun%d";
2791                 } else if (ifr->ifr_flags & IFF_TAP) {
2792                         /* TAP device */
2793                         flags |= IFF_TAP;
2794                         name = "tap%d";
2795                 } else
2796                         return -EINVAL;
2797
2798                 if (*ifr->ifr_name)
2799                         name = ifr->ifr_name;
2800
2801                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2802                                        NET_NAME_UNKNOWN, tun_setup, queues,
2803                                        queues);
2804
2805                 if (!dev)
2806                         return -ENOMEM;
2807
2808                 dev_net_set(dev, net);
2809                 dev->rtnl_link_ops = &tun_link_ops;
2810                 dev->ifindex = tfile->ifindex;
2811                 dev->sysfs_groups[0] = &tun_attr_group;
2812
2813                 tun = netdev_priv(dev);
2814                 tun->dev = dev;
2815                 tun->flags = flags;
2816                 tun->txflt.count = 0;
2817                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2818
2819                 tun->align = NET_SKB_PAD;
2820                 tun->filter_attached = false;
2821                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2822                 tun->rx_batched = 0;
2823                 RCU_INIT_POINTER(tun->steering_prog, NULL);
2824
2825                 tun->ifr = ifr;
2826                 tun->file = file;
2827
2828                 tun_net_initialize(dev);
2829
2830                 err = register_netdevice(tun->dev);
2831                 if (err < 0) {
2832                         free_netdev(dev);
2833                         return err;
2834                 }
2835                 /* free_netdev() won't check refcnt, to avoid race
2836                  * with dev_put() we need publish tun after registration.
2837                  */
2838                 rcu_assign_pointer(tfile->tun, tun);
2839         }
2840
2841         if (ifr->ifr_flags & IFF_NO_CARRIER)
2842                 netif_carrier_off(tun->dev);
2843         else
2844                 netif_carrier_on(tun->dev);
2845
2846         /* Make sure persistent devices do not get stuck in
2847          * xoff state.
2848          */
2849         if (netif_running(tun->dev))
2850                 netif_tx_wake_all_queues(tun->dev);
2851
2852         strcpy(ifr->ifr_name, tun->dev->name);
2853         return 0;
2854 }
2855
2856 static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2857 {
2858         strcpy(ifr->ifr_name, tun->dev->name);
2859
2860         ifr->ifr_flags = tun_flags(tun);
2861
2862 }
2863
2864 /* This is like a cut-down ethtool ops, except done via tun fd so no
2865  * privs required. */
2866 static int set_offload(struct tun_struct *tun, unsigned long arg)
2867 {
2868         netdev_features_t features = 0;
2869
2870         if (arg & TUN_F_CSUM) {
2871                 features |= NETIF_F_HW_CSUM;
2872                 arg &= ~TUN_F_CSUM;
2873
2874                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2875                         if (arg & TUN_F_TSO_ECN) {
2876                                 features |= NETIF_F_TSO_ECN;
2877                                 arg &= ~TUN_F_TSO_ECN;
2878                         }
2879                         if (arg & TUN_F_TSO4)
2880                                 features |= NETIF_F_TSO;
2881                         if (arg & TUN_F_TSO6)
2882                                 features |= NETIF_F_TSO6;
2883                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2884                 }
2885
2886                 arg &= ~TUN_F_UFO;
2887
2888                 /* TODO: for now USO4 and USO6 should work simultaneously */
2889                 if (arg & TUN_F_USO4 && arg & TUN_F_USO6) {
2890                         features |= NETIF_F_GSO_UDP_L4;
2891                         arg &= ~(TUN_F_USO4 | TUN_F_USO6);
2892                 }
2893         }
2894
2895         /* This gives the user a way to test for new features in future by
2896          * trying to set them. */
2897         if (arg)
2898                 return -EINVAL;
2899
2900         tun->set_features = features;
2901         tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2902         tun->dev->wanted_features |= features;
2903         netdev_update_features(tun->dev);
2904
2905         return 0;
2906 }
2907
2908 static void tun_detach_filter(struct tun_struct *tun, int n)
2909 {
2910         int i;
2911         struct tun_file *tfile;
2912
2913         for (i = 0; i < n; i++) {
2914                 tfile = rtnl_dereference(tun->tfiles[i]);
2915                 lock_sock(tfile->socket.sk);
2916                 sk_detach_filter(tfile->socket.sk);
2917                 release_sock(tfile->socket.sk);
2918         }
2919
2920         tun->filter_attached = false;
2921 }
2922
2923 static int tun_attach_filter(struct tun_struct *tun)
2924 {
2925         int i, ret = 0;
2926         struct tun_file *tfile;
2927
2928         for (i = 0; i < tun->numqueues; i++) {
2929                 tfile = rtnl_dereference(tun->tfiles[i]);
2930                 lock_sock(tfile->socket.sk);
2931                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2932                 release_sock(tfile->socket.sk);
2933                 if (ret) {
2934                         tun_detach_filter(tun, i);
2935                         return ret;
2936                 }
2937         }
2938
2939         tun->filter_attached = true;
2940         return ret;
2941 }
2942
2943 static void tun_set_sndbuf(struct tun_struct *tun)
2944 {
2945         struct tun_file *tfile;
2946         int i;
2947
2948         for (i = 0; i < tun->numqueues; i++) {
2949                 tfile = rtnl_dereference(tun->tfiles[i]);
2950                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2951         }
2952 }
2953
2954 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2955 {
2956         struct tun_file *tfile = file->private_data;
2957         struct tun_struct *tun;
2958         int ret = 0;
2959
2960         rtnl_lock();
2961
2962         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2963                 tun = tfile->detached;
2964                 if (!tun) {
2965                         ret = -EINVAL;
2966                         goto unlock;
2967                 }
2968                 ret = security_tun_dev_attach_queue(tun->security);
2969                 if (ret < 0)
2970                         goto unlock;
2971                 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2972                                  tun->flags & IFF_NAPI_FRAGS, true);
2973         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2974                 tun = rtnl_dereference(tfile->tun);
2975                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2976                         ret = -EINVAL;
2977                 else
2978                         __tun_detach(tfile, false);
2979         } else
2980                 ret = -EINVAL;
2981
2982         if (ret >= 0)
2983                 netdev_state_change(tun->dev);
2984
2985 unlock:
2986         rtnl_unlock();
2987         return ret;
2988 }
2989
2990 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog __rcu **prog_p,
2991                         void __user *data)
2992 {
2993         struct bpf_prog *prog;
2994         int fd;
2995
2996         if (copy_from_user(&fd, data, sizeof(fd)))
2997                 return -EFAULT;
2998
2999         if (fd == -1) {
3000                 prog = NULL;
3001         } else {
3002                 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
3003                 if (IS_ERR(prog))
3004                         return PTR_ERR(prog);
3005         }
3006
3007         return __tun_set_ebpf(tun, prog_p, prog);
3008 }
3009
3010 /* Return correct value for tun->dev->addr_len based on tun->dev->type. */
3011 static unsigned char tun_get_addr_len(unsigned short type)
3012 {
3013         switch (type) {
3014         case ARPHRD_IP6GRE:
3015         case ARPHRD_TUNNEL6:
3016                 return sizeof(struct in6_addr);
3017         case ARPHRD_IPGRE:
3018         case ARPHRD_TUNNEL:
3019         case ARPHRD_SIT:
3020                 return 4;
3021         case ARPHRD_ETHER:
3022                 return ETH_ALEN;
3023         case ARPHRD_IEEE802154:
3024         case ARPHRD_IEEE802154_MONITOR:
3025                 return IEEE802154_EXTENDED_ADDR_LEN;
3026         case ARPHRD_PHONET_PIPE:
3027         case ARPHRD_PPP:
3028         case ARPHRD_NONE:
3029                 return 0;
3030         case ARPHRD_6LOWPAN:
3031                 return EUI64_ADDR_LEN;
3032         case ARPHRD_FDDI:
3033                 return FDDI_K_ALEN;
3034         case ARPHRD_HIPPI:
3035                 return HIPPI_ALEN;
3036         case ARPHRD_IEEE802:
3037                 return FC_ALEN;
3038         case ARPHRD_ROSE:
3039                 return ROSE_ADDR_LEN;
3040         case ARPHRD_NETROM:
3041                 return AX25_ADDR_LEN;
3042         case ARPHRD_LOCALTLK:
3043                 return LTALK_ALEN;
3044         default:
3045                 return 0;
3046         }
3047 }
3048
3049 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
3050                             unsigned long arg, int ifreq_len)
3051 {
3052         struct tun_file *tfile = file->private_data;
3053         struct net *net = sock_net(&tfile->sk);
3054         struct tun_struct *tun;
3055         void __user* argp = (void __user*)arg;
3056         unsigned int ifindex, carrier;
3057         struct ifreq ifr;
3058         kuid_t owner;
3059         kgid_t group;
3060         int sndbuf;
3061         int vnet_hdr_sz;
3062         int le;
3063         int ret;
3064         bool do_notify = false;
3065
3066         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3067             (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3068                 if (copy_from_user(&ifr, argp, ifreq_len))
3069                         return -EFAULT;
3070         } else {
3071                 memset(&ifr, 0, sizeof(ifr));
3072         }
3073         if (cmd == TUNGETFEATURES) {
3074                 /* Currently this just means: "what IFF flags are valid?".
3075                  * This is needed because we never checked for invalid flags on
3076                  * TUNSETIFF.
3077                  */
3078                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_CARRIER |
3079                                 TUN_FEATURES, (unsigned int __user*)argp);
3080         } else if (cmd == TUNSETQUEUE) {
3081                 return tun_set_queue(file, &ifr);
3082         } else if (cmd == SIOCGSKNS) {
3083                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3084                         return -EPERM;
3085                 return open_related_ns(&net->ns, get_net_ns);
3086         }
3087
3088         rtnl_lock();
3089
3090         tun = tun_get(tfile);
3091         if (cmd == TUNSETIFF) {
3092                 ret = -EEXIST;
3093                 if (tun)
3094                         goto unlock;
3095
3096                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3097
3098                 ret = tun_set_iff(net, file, &ifr);
3099
3100                 if (ret)
3101                         goto unlock;
3102
3103                 if (copy_to_user(argp, &ifr, ifreq_len))
3104                         ret = -EFAULT;
3105                 goto unlock;
3106         }
3107         if (cmd == TUNSETIFINDEX) {
3108                 ret = -EPERM;
3109                 if (tun)
3110                         goto unlock;
3111
3112                 ret = -EFAULT;
3113                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3114                         goto unlock;
3115
3116                 ret = 0;
3117                 tfile->ifindex = ifindex;
3118                 goto unlock;
3119         }
3120
3121         ret = -EBADFD;
3122         if (!tun)
3123                 goto unlock;
3124
3125         netif_info(tun, drv, tun->dev, "tun_chr_ioctl cmd %u\n", cmd);
3126
3127         net = dev_net(tun->dev);
3128         ret = 0;
3129         switch (cmd) {
3130         case TUNGETIFF:
3131                 tun_get_iff(tun, &ifr);
3132
3133                 if (tfile->detached)
3134                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
3135                 if (!tfile->socket.sk->sk_filter)
3136                         ifr.ifr_flags |= IFF_NOFILTER;
3137
3138                 if (copy_to_user(argp, &ifr, ifreq_len))
3139                         ret = -EFAULT;
3140                 break;
3141
3142         case TUNSETNOCSUM:
3143                 /* Disable/Enable checksum */
3144
3145                 /* [unimplemented] */
3146                 netif_info(tun, drv, tun->dev, "ignored: set checksum %s\n",
3147                            arg ? "disabled" : "enabled");
3148                 break;
3149
3150         case TUNSETPERSIST:
3151                 /* Disable/Enable persist mode. Keep an extra reference to the
3152                  * module to prevent the module being unprobed.
3153                  */
3154                 if (arg && !(tun->flags & IFF_PERSIST)) {
3155                         tun->flags |= IFF_PERSIST;
3156                         __module_get(THIS_MODULE);
3157                         do_notify = true;
3158                 }
3159                 if (!arg && (tun->flags & IFF_PERSIST)) {
3160                         tun->flags &= ~IFF_PERSIST;
3161                         module_put(THIS_MODULE);
3162                         do_notify = true;
3163                 }
3164
3165                 netif_info(tun, drv, tun->dev, "persist %s\n",
3166                            arg ? "enabled" : "disabled");
3167                 break;
3168
3169         case TUNSETOWNER:
3170                 /* Set owner of the device */
3171                 owner = make_kuid(current_user_ns(), arg);
3172                 if (!uid_valid(owner)) {
3173                         ret = -EINVAL;
3174                         break;
3175                 }
3176                 tun->owner = owner;
3177                 do_notify = true;
3178                 netif_info(tun, drv, tun->dev, "owner set to %u\n",
3179                            from_kuid(&init_user_ns, tun->owner));
3180                 break;
3181
3182         case TUNSETGROUP:
3183                 /* Set group of the device */
3184                 group = make_kgid(current_user_ns(), arg);
3185                 if (!gid_valid(group)) {
3186                         ret = -EINVAL;
3187                         break;
3188                 }
3189                 tun->group = group;
3190                 do_notify = true;
3191                 netif_info(tun, drv, tun->dev, "group set to %u\n",
3192                            from_kgid(&init_user_ns, tun->group));
3193                 break;
3194
3195         case TUNSETLINK:
3196                 /* Only allow setting the type when the interface is down */
3197                 if (tun->dev->flags & IFF_UP) {
3198                         netif_info(tun, drv, tun->dev,
3199                                    "Linktype set failed because interface is up\n");
3200                         ret = -EBUSY;
3201                 } else {
3202                         ret = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE,
3203                                                        tun->dev);
3204                         ret = notifier_to_errno(ret);
3205                         if (ret) {
3206                                 netif_info(tun, drv, tun->dev,
3207                                            "Refused to change device type\n");
3208                                 break;
3209                         }
3210                         tun->dev->type = (int) arg;
3211                         tun->dev->addr_len = tun_get_addr_len(tun->dev->type);
3212                         netif_info(tun, drv, tun->dev, "linktype set to %d\n",
3213                                    tun->dev->type);
3214                         call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE,
3215                                                  tun->dev);
3216                 }
3217                 break;
3218
3219         case TUNSETDEBUG:
3220                 tun->msg_enable = (u32)arg;
3221                 break;
3222
3223         case TUNSETOFFLOAD:
3224                 ret = set_offload(tun, arg);
3225                 break;
3226
3227         case TUNSETTXFILTER:
3228                 /* Can be set only for TAPs */
3229                 ret = -EINVAL;
3230                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3231                         break;
3232                 ret = update_filter(&tun->txflt, (void __user *)arg);
3233                 break;
3234
3235         case SIOCGIFHWADDR:
3236                 /* Get hw address */
3237                 dev_get_mac_address(&ifr.ifr_hwaddr, net, tun->dev->name);
3238                 if (copy_to_user(argp, &ifr, ifreq_len))
3239                         ret = -EFAULT;
3240                 break;
3241
3242         case SIOCSIFHWADDR:
3243                 /* Set hw address */
3244                 ret = dev_set_mac_address_user(tun->dev, &ifr.ifr_hwaddr, NULL);
3245                 break;
3246
3247         case TUNGETSNDBUF:
3248                 sndbuf = tfile->socket.sk->sk_sndbuf;
3249                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3250                         ret = -EFAULT;
3251                 break;
3252
3253         case TUNSETSNDBUF:
3254                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3255                         ret = -EFAULT;
3256                         break;
3257                 }
3258                 if (sndbuf <= 0) {
3259                         ret = -EINVAL;
3260                         break;
3261                 }
3262
3263                 tun->sndbuf = sndbuf;
3264                 tun_set_sndbuf(tun);
3265                 break;
3266
3267         case TUNGETVNETHDRSZ:
3268                 vnet_hdr_sz = tun->vnet_hdr_sz;
3269                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3270                         ret = -EFAULT;
3271                 break;
3272
3273         case TUNSETVNETHDRSZ:
3274                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3275                         ret = -EFAULT;
3276                         break;
3277                 }
3278                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3279                         ret = -EINVAL;
3280                         break;
3281                 }
3282
3283                 tun->vnet_hdr_sz = vnet_hdr_sz;
3284                 break;
3285
3286         case TUNGETVNETLE:
3287                 le = !!(tun->flags & TUN_VNET_LE);
3288                 if (put_user(le, (int __user *)argp))
3289                         ret = -EFAULT;
3290                 break;
3291
3292         case TUNSETVNETLE:
3293                 if (get_user(le, (int __user *)argp)) {
3294                         ret = -EFAULT;
3295                         break;
3296                 }
3297                 if (le)
3298                         tun->flags |= TUN_VNET_LE;
3299                 else
3300                         tun->flags &= ~TUN_VNET_LE;
3301                 break;
3302
3303         case TUNGETVNETBE:
3304                 ret = tun_get_vnet_be(tun, argp);
3305                 break;
3306
3307         case TUNSETVNETBE:
3308                 ret = tun_set_vnet_be(tun, argp);
3309                 break;
3310
3311         case TUNATTACHFILTER:
3312                 /* Can be set only for TAPs */
3313                 ret = -EINVAL;
3314                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3315                         break;
3316                 ret = -EFAULT;
3317                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3318                         break;
3319
3320                 ret = tun_attach_filter(tun);
3321                 break;
3322
3323         case TUNDETACHFILTER:
3324                 /* Can be set only for TAPs */
3325                 ret = -EINVAL;
3326                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3327                         break;
3328                 ret = 0;
3329                 tun_detach_filter(tun, tun->numqueues);
3330                 break;
3331
3332         case TUNGETFILTER:
3333                 ret = -EINVAL;
3334                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3335                         break;
3336                 ret = -EFAULT;
3337                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3338                         break;
3339                 ret = 0;
3340                 break;
3341
3342         case TUNSETSTEERINGEBPF:
3343                 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3344                 break;
3345
3346         case TUNSETFILTEREBPF:
3347                 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3348                 break;
3349
3350         case TUNSETCARRIER:
3351                 ret = -EFAULT;
3352                 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3353                         goto unlock;
3354
3355                 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3356                 break;
3357
3358         case TUNGETDEVNETNS:
3359                 ret = -EPERM;
3360                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3361                         goto unlock;
3362                 ret = open_related_ns(&net->ns, get_net_ns);
3363                 break;
3364
3365         default:
3366                 ret = -EINVAL;
3367                 break;
3368         }
3369
3370         if (do_notify)
3371                 netdev_state_change(tun->dev);
3372
3373 unlock:
3374         rtnl_unlock();
3375         if (tun)
3376                 tun_put(tun);
3377         return ret;
3378 }
3379
3380 static long tun_chr_ioctl(struct file *file,
3381                           unsigned int cmd, unsigned long arg)
3382 {
3383         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3384 }
3385
3386 #ifdef CONFIG_COMPAT
3387 static long tun_chr_compat_ioctl(struct file *file,
3388                          unsigned int cmd, unsigned long arg)
3389 {
3390         switch (cmd) {
3391         case TUNSETIFF:
3392         case TUNGETIFF:
3393         case TUNSETTXFILTER:
3394         case TUNGETSNDBUF:
3395         case TUNSETSNDBUF:
3396         case SIOCGIFHWADDR:
3397         case SIOCSIFHWADDR:
3398                 arg = (unsigned long)compat_ptr(arg);
3399                 break;
3400         default:
3401                 arg = (compat_ulong_t)arg;
3402                 break;
3403         }
3404
3405         /*
3406          * compat_ifreq is shorter than ifreq, so we must not access beyond
3407          * the end of that structure. All fields that are used in this
3408          * driver are compatible though, we don't need to convert the
3409          * contents.
3410          */
3411         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3412 }
3413 #endif /* CONFIG_COMPAT */
3414
3415 static int tun_chr_fasync(int fd, struct file *file, int on)
3416 {
3417         struct tun_file *tfile = file->private_data;
3418         int ret;
3419
3420         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3421                 goto out;
3422
3423         if (on) {
3424                 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3425                 tfile->flags |= TUN_FASYNC;
3426         } else
3427                 tfile->flags &= ~TUN_FASYNC;
3428         ret = 0;
3429 out:
3430         return ret;
3431 }
3432
3433 static int tun_chr_open(struct inode *inode, struct file * file)
3434 {
3435         struct net *net = current->nsproxy->net_ns;
3436         struct tun_file *tfile;
3437
3438         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3439                                             &tun_proto, 0);
3440         if (!tfile)
3441                 return -ENOMEM;
3442         if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3443                 sk_free(&tfile->sk);
3444                 return -ENOMEM;
3445         }
3446
3447         mutex_init(&tfile->napi_mutex);
3448         RCU_INIT_POINTER(tfile->tun, NULL);
3449         tfile->flags = 0;
3450         tfile->ifindex = 0;
3451
3452         init_waitqueue_head(&tfile->socket.wq.wait);
3453
3454         tfile->socket.file = file;
3455         tfile->socket.ops = &tun_socket_ops;
3456
3457         sock_init_data_uid(&tfile->socket, &tfile->sk, inode->i_uid);
3458
3459         tfile->sk.sk_write_space = tun_sock_write_space;
3460         tfile->sk.sk_sndbuf = INT_MAX;
3461
3462         file->private_data = tfile;
3463         INIT_LIST_HEAD(&tfile->next);
3464
3465         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3466
3467         /* tun groks IOCB_NOWAIT just fine, mark it as such */
3468         file->f_mode |= FMODE_NOWAIT;
3469         return 0;
3470 }
3471
3472 static int tun_chr_close(struct inode *inode, struct file *file)
3473 {
3474         struct tun_file *tfile = file->private_data;
3475
3476         tun_detach(tfile, true);
3477
3478         return 0;
3479 }
3480
3481 #ifdef CONFIG_PROC_FS
3482 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3483 {
3484         struct tun_file *tfile = file->private_data;
3485         struct tun_struct *tun;
3486         struct ifreq ifr;
3487
3488         memset(&ifr, 0, sizeof(ifr));
3489
3490         rtnl_lock();
3491         tun = tun_get(tfile);
3492         if (tun)
3493                 tun_get_iff(tun, &ifr);
3494         rtnl_unlock();
3495
3496         if (tun)
3497                 tun_put(tun);
3498
3499         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3500 }
3501 #endif
3502
3503 static const struct file_operations tun_fops = {
3504         .owner  = THIS_MODULE,
3505         .llseek = no_llseek,
3506         .read_iter  = tun_chr_read_iter,
3507         .write_iter = tun_chr_write_iter,
3508         .poll   = tun_chr_poll,
3509         .unlocked_ioctl = tun_chr_ioctl,
3510 #ifdef CONFIG_COMPAT
3511         .compat_ioctl = tun_chr_compat_ioctl,
3512 #endif
3513         .open   = tun_chr_open,
3514         .release = tun_chr_close,
3515         .fasync = tun_chr_fasync,
3516 #ifdef CONFIG_PROC_FS
3517         .show_fdinfo = tun_chr_show_fdinfo,
3518 #endif
3519 };
3520
3521 static struct miscdevice tun_miscdev = {
3522         .minor = TUN_MINOR,
3523         .name = "tun",
3524         .nodename = "net/tun",
3525         .fops = &tun_fops,
3526 };
3527
3528 /* ethtool interface */
3529
3530 static void tun_default_link_ksettings(struct net_device *dev,
3531                                        struct ethtool_link_ksettings *cmd)
3532 {
3533         ethtool_link_ksettings_zero_link_mode(cmd, supported);
3534         ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3535         cmd->base.speed         = SPEED_10000;
3536         cmd->base.duplex        = DUPLEX_FULL;
3537         cmd->base.port          = PORT_TP;
3538         cmd->base.phy_address   = 0;
3539         cmd->base.autoneg       = AUTONEG_DISABLE;
3540 }
3541
3542 static int tun_get_link_ksettings(struct net_device *dev,
3543                                   struct ethtool_link_ksettings *cmd)
3544 {
3545         struct tun_struct *tun = netdev_priv(dev);
3546
3547         memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3548         return 0;
3549 }
3550
3551 static int tun_set_link_ksettings(struct net_device *dev,
3552                                   const struct ethtool_link_ksettings *cmd)
3553 {
3554         struct tun_struct *tun = netdev_priv(dev);
3555
3556         memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3557         return 0;
3558 }
3559
3560 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3561 {
3562         struct tun_struct *tun = netdev_priv(dev);
3563
3564         strscpy(info->driver, DRV_NAME, sizeof(info->driver));
3565         strscpy(info->version, DRV_VERSION, sizeof(info->version));
3566
3567         switch (tun->flags & TUN_TYPE_MASK) {
3568         case IFF_TUN:
3569                 strscpy(info->bus_info, "tun", sizeof(info->bus_info));
3570                 break;
3571         case IFF_TAP:
3572                 strscpy(info->bus_info, "tap", sizeof(info->bus_info));
3573                 break;
3574         }
3575 }
3576
3577 static u32 tun_get_msglevel(struct net_device *dev)
3578 {
3579         struct tun_struct *tun = netdev_priv(dev);
3580
3581         return tun->msg_enable;
3582 }
3583
3584 static void tun_set_msglevel(struct net_device *dev, u32 value)
3585 {
3586         struct tun_struct *tun = netdev_priv(dev);
3587
3588         tun->msg_enable = value;
3589 }
3590
3591 static int tun_get_coalesce(struct net_device *dev,
3592                             struct ethtool_coalesce *ec,
3593                             struct kernel_ethtool_coalesce *kernel_coal,
3594                             struct netlink_ext_ack *extack)
3595 {
3596         struct tun_struct *tun = netdev_priv(dev);
3597
3598         ec->rx_max_coalesced_frames = tun->rx_batched;
3599
3600         return 0;
3601 }
3602
3603 static int tun_set_coalesce(struct net_device *dev,
3604                             struct ethtool_coalesce *ec,
3605                             struct kernel_ethtool_coalesce *kernel_coal,
3606                             struct netlink_ext_ack *extack)
3607 {
3608         struct tun_struct *tun = netdev_priv(dev);
3609
3610         if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3611                 tun->rx_batched = NAPI_POLL_WEIGHT;
3612         else
3613                 tun->rx_batched = ec->rx_max_coalesced_frames;
3614
3615         return 0;
3616 }
3617
3618 static const struct ethtool_ops tun_ethtool_ops = {
3619         .supported_coalesce_params = ETHTOOL_COALESCE_RX_MAX_FRAMES,
3620         .get_drvinfo    = tun_get_drvinfo,
3621         .get_msglevel   = tun_get_msglevel,
3622         .set_msglevel   = tun_set_msglevel,
3623         .get_link       = ethtool_op_get_link,
3624         .get_ts_info    = ethtool_op_get_ts_info,
3625         .get_coalesce   = tun_get_coalesce,
3626         .set_coalesce   = tun_set_coalesce,
3627         .get_link_ksettings = tun_get_link_ksettings,
3628         .set_link_ksettings = tun_set_link_ksettings,
3629 };
3630
3631 static int tun_queue_resize(struct tun_struct *tun)
3632 {
3633         struct net_device *dev = tun->dev;
3634         struct tun_file *tfile;
3635         struct ptr_ring **rings;
3636         int n = tun->numqueues + tun->numdisabled;
3637         int ret, i;
3638
3639         rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3640         if (!rings)
3641                 return -ENOMEM;
3642
3643         for (i = 0; i < tun->numqueues; i++) {
3644                 tfile = rtnl_dereference(tun->tfiles[i]);
3645                 rings[i] = &tfile->tx_ring;
3646         }
3647         list_for_each_entry(tfile, &tun->disabled, next)
3648                 rings[i++] = &tfile->tx_ring;
3649
3650         ret = ptr_ring_resize_multiple(rings, n,
3651                                        dev->tx_queue_len, GFP_KERNEL,
3652                                        tun_ptr_free);
3653
3654         kfree(rings);
3655         return ret;
3656 }
3657
3658 static int tun_device_event(struct notifier_block *unused,
3659                             unsigned long event, void *ptr)
3660 {
3661         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3662         struct tun_struct *tun = netdev_priv(dev);
3663         int i;
3664
3665         if (dev->rtnl_link_ops != &tun_link_ops)
3666                 return NOTIFY_DONE;
3667
3668         switch (event) {
3669         case NETDEV_CHANGE_TX_QUEUE_LEN:
3670                 if (tun_queue_resize(tun))
3671                         return NOTIFY_BAD;
3672                 break;
3673         case NETDEV_UP:
3674                 for (i = 0; i < tun->numqueues; i++) {
3675                         struct tun_file *tfile;
3676
3677                         tfile = rtnl_dereference(tun->tfiles[i]);
3678                         tfile->socket.sk->sk_write_space(tfile->socket.sk);
3679                 }
3680                 break;
3681         default:
3682                 break;
3683         }
3684
3685         return NOTIFY_DONE;
3686 }
3687
3688 static struct notifier_block tun_notifier_block __read_mostly = {
3689         .notifier_call  = tun_device_event,
3690 };
3691
3692 static int __init tun_init(void)
3693 {
3694         int ret = 0;
3695
3696         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3697
3698         ret = rtnl_link_register(&tun_link_ops);
3699         if (ret) {
3700                 pr_err("Can't register link_ops\n");
3701                 goto err_linkops;
3702         }
3703
3704         ret = misc_register(&tun_miscdev);
3705         if (ret) {
3706                 pr_err("Can't register misc device %d\n", TUN_MINOR);
3707                 goto err_misc;
3708         }
3709
3710         ret = register_netdevice_notifier(&tun_notifier_block);
3711         if (ret) {
3712                 pr_err("Can't register netdevice notifier\n");
3713                 goto err_notifier;
3714         }
3715
3716         return  0;
3717
3718 err_notifier:
3719         misc_deregister(&tun_miscdev);
3720 err_misc:
3721         rtnl_link_unregister(&tun_link_ops);
3722 err_linkops:
3723         return ret;
3724 }
3725
3726 static void tun_cleanup(void)
3727 {
3728         misc_deregister(&tun_miscdev);
3729         rtnl_link_unregister(&tun_link_ops);
3730         unregister_netdevice_notifier(&tun_notifier_block);
3731 }
3732
3733 /* Get an underlying socket object from tun file.  Returns error unless file is
3734  * attached to a device.  The returned object works like a packet socket, it
3735  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
3736  * holding a reference to the file for as long as the socket is in use. */
3737 struct socket *tun_get_socket(struct file *file)
3738 {
3739         struct tun_file *tfile;
3740         if (file->f_op != &tun_fops)
3741                 return ERR_PTR(-EINVAL);
3742         tfile = file->private_data;
3743         if (!tfile)
3744                 return ERR_PTR(-EBADFD);
3745         return &tfile->socket;
3746 }
3747 EXPORT_SYMBOL_GPL(tun_get_socket);
3748
3749 struct ptr_ring *tun_get_tx_ring(struct file *file)
3750 {
3751         struct tun_file *tfile;
3752
3753         if (file->f_op != &tun_fops)
3754                 return ERR_PTR(-EINVAL);
3755         tfile = file->private_data;
3756         if (!tfile)
3757                 return ERR_PTR(-EBADFD);
3758         return &tfile->tx_ring;
3759 }
3760 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3761
3762 module_init(tun_init);
3763 module_exit(tun_cleanup);
3764 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3765 MODULE_AUTHOR(DRV_COPYRIGHT);
3766 MODULE_LICENSE("GPL");
3767 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3768 MODULE_ALIAS("devname:net/tun");