drivers/net/tun.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  TUN - Universal TUN/TAP device driver.
   4  *  Copyright (C) 1999-2002 Maxim Krasnyansky <[email protected]>
   5  *
   6  *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
   7  */
   8
   9 /*
  10  *  Changes:
  11  *
  12  *  Mike Kershaw <[email protected]> 2005/08/14
  13  *    Add TUNSETLINK ioctl to set the link encapsulation
  14  *
  15  *  Mark Smith <[email protected]>
  16  *    Use eth_random_addr() for tap MAC address.
  17  *
  18  *  Harald Roelle <[email protected]>  2004/04/20
  19  *    Fixes in packet dropping, queue length setting and queue wakeup.
  20  *    Increased default tx queue length.
  21  *    Added ethtool API.
  22  *    Minor cleanups
  23  *
  24  *  Daniel Podlejski <[email protected]>
  25  *    Modifications for 2.3.99-pre5 kernel.
  26  */
  27
  28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  29
  30 #define DRV_NAME        "tun"
  31 #define DRV_VERSION     "1.6"
  32 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  33 #define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <[email protected]>"
  34
  35 #include <linux/module.h>
  36 #include <linux/errno.h>
  37 #include <linux/kernel.h>
  38 #include <linux/sched/signal.h>
  39 #include <linux/major.h>
  40 #include <linux/slab.h>
  41 #include <linux/poll.h>
  42 #include <linux/fcntl.h>
  43 #include <linux/init.h>
  44 #include <linux/skbuff.h>
  45 #include <linux/netdevice.h>
  46 #include <linux/etherdevice.h>
  47 #include <linux/miscdevice.h>
  48 #include <linux/ethtool.h>
  49 #include <linux/rtnetlink.h>
  50 #include <linux/compat.h>
  51 #include <linux/if.h>
  52 #include <linux/if_arp.h>
  53 #include <linux/if_ether.h>
  54 #include <linux/if_tun.h>
  55 #include <linux/if_vlan.h>
  56 #include <linux/crc32.h>
  57 #include <linux/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 <linux/seq_file.h>
  66 #include <linux/uio.h>
  67 #include <linux/skb_array.h>
  68 #include <linux/bpf.h>
  69 #include <linux/bpf_trace.h>
  70 #include <linux/mutex.h>
  71
  72 #include <linux/uaccess.h>
  73 #include <linux/proc_fs.h>
  74
  75 static void tun_default_link_ksettings(struct net_device *dev,
  76                                        struct ethtool_link_ksettings *cmd);
  77
  78 /* Uncomment to enable debugging */
  79 /* #define TUN_DEBUG 1 */
  80
  81 #ifdef TUN_DEBUG
  82 static int debug;
  83
  84 #define tun_debug(level, tun, fmt, args...)                     \
  85 do {                                                            \
  86         if (tun->debug)                                         \
  87                 netdev_printk(level, tun->dev, fmt, ##args);    \
  88 } while (0)
  89 #define DBG1(level, fmt, args...)                               \
  90 do {                                                            \
  91         if (debug == 2)                                         \
  92                 printk(level fmt, ##args);                      \
  93 } while (0)
  94 #else
  95 #define tun_debug(level, tun, fmt, args...)                     \
  96 do {                                                            \
  97         if (0)                                                  \
  98                 netdev_printk(level, tun->dev, fmt, ##args);    \
  99 } while (0)
 100 #define DBG1(level, fmt, args...)                               \
 101 do {                                                            \
 102         if (0)                                                  \
 103                 printk(level fmt, ##args);                      \
 104 } while (0)
 105 #endif
 106
 107 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
 108
 109 /* TUN device flags */
 110
 111 /* IFF_ATTACH_QUEUE is never stored in device flags,
 112  * overload it to mean fasync when stored there.
 113  */
 114 #define TUN_FASYNC      IFF_ATTACH_QUEUE
 115 /* High bits in flags field are unused. */
 116 #define TUN_VNET_LE     0x80000000
 117 #define TUN_VNET_BE     0x40000000
 118
 119 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
 120                       IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
 121
 122 #define GOODCOPY_LEN 128
 123
 124 #define FLT_EXACT_COUNT 8
 125 struct tap_filter {
 126         unsigned int    count;    /* Number of addrs. Zero means disabled */
 127         u32             mask[2];  /* Mask of the hashed addrs */
 128         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 129 };
 130
 131 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
 132  * to max number of VCPUs in guest. */
 133 #define MAX_TAP_QUEUES 256
 134 #define MAX_TAP_FLOWS  4096
 135
 136 #define TUN_FLOW_EXPIRE (3 * HZ)
 137
 138 struct tun_pcpu_stats {
 139         u64 rx_packets;
 140         u64 rx_bytes;
 141         u64 tx_packets;
 142         u64 tx_bytes;
 143         struct u64_stats_sync syncp;
 144         u32 rx_dropped;
 145         u32 tx_dropped;
 146         u32 rx_frame_errors;
 147 };
 148
 149 /* A tun_file connects an open character device to a tuntap netdevice. It
 150  * also contains all socket related structures (except sock_fprog and tap_filter)
 151  * to serve as one transmit queue for tuntap device. The sock_fprog and
 152  * tap_filter were kept in tun_struct since they were used for filtering for the
 153  * netdevice not for a specific queue (at least I didn't see the requirement for
 154  * this).
 155  *
 156  * RCU usage:
 157  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
 158  * other can only be read while rcu_read_lock or rtnl_lock is held.
 159  */
 160 struct tun_file {
 161         struct sock sk;
 162         struct socket socket;
 163         struct tun_struct __rcu *tun;
 164         struct fasync_struct *fasync;
 165         /* only used for fasnyc */
 166         unsigned int flags;
 167         union {
 168                 u16 queue_index;
 169                 unsigned int ifindex;
 170         };
 171         struct napi_struct napi;
 172         bool napi_enabled;
 173         bool napi_frags_enabled;
 174         struct mutex napi_mutex;        /* Protects access to the above napi */
 175         struct list_head next;
 176         struct tun_struct *detached;
 177         struct ptr_ring tx_ring;
 178         struct xdp_rxq_info xdp_rxq;
 179 };
 180
 181 struct tun_page {
 182         struct page *page;
 183         int count;
 184 };
 185
 186 struct tun_flow_entry {
 187         struct hlist_node hash_link;
 188         struct rcu_head rcu;
 189         struct tun_struct *tun;
 190
 191         u32 rxhash;
 192         u32 rps_rxhash;
 193         int queue_index;
 194         unsigned long updated ____cacheline_aligned_in_smp;
 195 };
 196
 197 #define TUN_NUM_FLOW_ENTRIES 1024
 198 #define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
 199
 200 struct tun_prog {
 201         struct rcu_head rcu;
 202         struct bpf_prog *prog;
 203 };
 204
 205 /* Since the socket were moved to tun_file, to preserve the behavior of persist
 206  * device, socket filter, sndbuf and vnet header size were restore when the
 207  * file were attached to a persist device.
 208  */
 209 struct tun_struct {
 210         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
 211         unsigned int            numqueues;
 212         unsigned int            flags;
 213         kuid_t                  owner;
 214         kgid_t                  group;
 215
 216         struct net_device       *dev;
 217         netdev_features_t       set_features;
 218 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 219                           NETIF_F_TSO6)
 220
 221         int                     align;
 222         int                     vnet_hdr_sz;
 223         int                     sndbuf;
 224         struct tap_filter       txflt;
 225         struct sock_fprog       fprog;
 226         /* protected by rtnl lock */
 227         bool                    filter_attached;
 228 #ifdef TUN_DEBUG
 229         int debug;
 230 #endif
 231         spinlock_t lock;
 232         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 233         struct timer_list flow_gc_timer;
 234         unsigned long ageing_time;
 235         unsigned int numdisabled;
 236         struct list_head disabled;
 237         void *security;
 238         u32 flow_count;
 239         u32 rx_batched;
 240         struct tun_pcpu_stats __percpu *pcpu_stats;
 241         struct bpf_prog __rcu *xdp_prog;
 242         struct tun_prog __rcu *steering_prog;
 243         struct tun_prog __rcu *filter_prog;
 244         struct ethtool_link_ksettings link_ksettings;
 245 };
 246
 247 struct veth {
 248         __be16 h_vlan_proto;
 249         __be16 h_vlan_TCI;
 250 };
 251
 252 bool tun_is_xdp_frame(void *ptr)
 253 {
 254         return (unsigned long)ptr & TUN_XDP_FLAG;
 255 }
 256 EXPORT_SYMBOL(tun_is_xdp_frame);
 257
 258 void *tun_xdp_to_ptr(void *ptr)
 259 {
 260         return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
 261 }
 262 EXPORT_SYMBOL(tun_xdp_to_ptr);
 263
 264 void *tun_ptr_to_xdp(void *ptr)
 265 {
 266         return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
 267 }
 268 EXPORT_SYMBOL(tun_ptr_to_xdp);
 269
 270 static int tun_napi_receive(struct napi_struct *napi, int budget)
 271 {
 272         struct tun_file *tfile = container_of(napi, struct tun_file, napi);
 273         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
 274         struct sk_buff_head process_queue;
 275         struct sk_buff *skb;
 276         int received = 0;
 277
 278         __skb_queue_head_init(&process_queue);
 279
 280         spin_lock(&queue->lock);
 281         skb_queue_splice_tail_init(queue, &process_queue);
 282         spin_unlock(&queue->lock);
 283
 284         while (received < budget && (skb = __skb_dequeue(&process_queue))) {
 285                 napi_gro_receive(napi, skb);
 286                 ++received;
 287         }
 288
 289         if (!skb_queue_empty(&process_queue)) {
 290                 spin_lock(&queue->lock);
 291                 skb_queue_splice(&process_queue, queue);
 292                 spin_unlock(&queue->lock);
 293         }
 294
 295         return received;
 296 }
 297
 298 static int tun_napi_poll(struct napi_struct *napi, int budget)
 299 {
 300         unsigned int received;
 301
 302         received = tun_napi_receive(napi, budget);
 303
 304         if (received < budget)
 305                 napi_complete_done(napi, received);
 306
 307         return received;
 308 }
 309
 310 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
 311                           bool napi_en, bool napi_frags)
 312 {
 313         tfile->napi_enabled = napi_en;
 314         tfile->napi_frags_enabled = napi_en && napi_frags;
 315         if (napi_en) {
 316                 netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
 317                                NAPI_POLL_WEIGHT);
 318                 napi_enable(&tfile->napi);
 319         }
 320 }
 321
 322 static void tun_napi_disable(struct tun_file *tfile)
 323 {
 324         if (tfile->napi_enabled)
 325                 napi_disable(&tfile->napi);
 326 }
 327
 328 static void tun_napi_del(struct tun_file *tfile)
 329 {
 330         if (tfile->napi_enabled)
 331                 netif_napi_del(&tfile->napi);
 332 }
 333
 334 static bool tun_napi_frags_enabled(const struct tun_file *tfile)
 335 {
 336         return tfile->napi_frags_enabled;
 337 }
 338
 339 #ifdef CONFIG_TUN_VNET_CROSS_LE
 340 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 341 {
 342         return tun->flags & TUN_VNET_BE ? false :
 343                 virtio_legacy_is_little_endian();
 344 }
 345
 346 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 347 {
 348         int be = !!(tun->flags & TUN_VNET_BE);
 349
 350         if (put_user(be, argp))
 351                 return -EFAULT;
 352
 353         return 0;
 354 }
 355
 356 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 357 {
 358         int be;
 359
 360         if (get_user(be, argp))
 361                 return -EFAULT;
 362
 363         if (be)
 364                 tun->flags |= TUN_VNET_BE;
 365         else
 366                 tun->flags &= ~TUN_VNET_BE;
 367
 368         return 0;
 369 }
 370 #else
 371 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 372 {
 373         return virtio_legacy_is_little_endian();
 374 }
 375
 376 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 377 {
 378         return -EINVAL;
 379 }
 380
 381 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 382 {
 383         return -EINVAL;
 384 }
 385 #endif /* CONFIG_TUN_VNET_CROSS_LE */
 386
 387 static inline bool tun_is_little_endian(struct tun_struct *tun)
 388 {
 389         return tun->flags & TUN_VNET_LE ||
 390                 tun_legacy_is_little_endian(tun);
 391 }
 392
 393 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
 394 {
 395         return __virtio16_to_cpu(tun_is_little_endian(tun), val);
 396 }
 397
 398 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
 399 {
 400         return __cpu_to_virtio16(tun_is_little_endian(tun), val);
 401 }
 402
 403 static inline u32 tun_hashfn(u32 rxhash)
 404 {
 405         return rxhash & TUN_MASK_FLOW_ENTRIES;
 406 }
 407
 408 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 409 {
 410         struct tun_flow_entry *e;
 411
 412         hlist_for_each_entry_rcu(e, head, hash_link) {
 413                 if (e->rxhash == rxhash)
 414                         return e;
 415         }
 416         return NULL;
 417 }
 418
 419 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 420                                               struct hlist_head *head,
 421                                               u32 rxhash, u16 queue_index)
 422 {
 423         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 424
 425         if (e) {
 426                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 427                           rxhash, queue_index);
 428                 e->updated = jiffies;
 429                 e->rxhash = rxhash;
 430                 e->rps_rxhash = 0;
 431                 e->queue_index = queue_index;
 432                 e->tun = tun;
 433                 hlist_add_head_rcu(&e->hash_link, head);
 434                 ++tun->flow_count;
 435         }
 436         return e;
 437 }
 438
 439 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 440 {
 441         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 442                   e->rxhash, e->queue_index);
 443         hlist_del_rcu(&e->hash_link);
 444         kfree_rcu(e, rcu);
 445         --tun->flow_count;
 446 }
 447
 448 static void tun_flow_flush(struct tun_struct *tun)
 449 {
 450         int i;
 451
 452         spin_lock_bh(&tun->lock);
 453         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 454                 struct tun_flow_entry *e;
 455                 struct hlist_node *n;
 456
 457                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 458                         tun_flow_delete(tun, e);
 459         }
 460         spin_unlock_bh(&tun->lock);
 461 }
 462
 463 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 464 {
 465         int i;
 466
 467         spin_lock_bh(&tun->lock);
 468         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 469                 struct tun_flow_entry *e;
 470                 struct hlist_node *n;
 471
 472                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 473                         if (e->queue_index == queue_index)
 474                                 tun_flow_delete(tun, e);
 475                 }
 476         }
 477         spin_unlock_bh(&tun->lock);
 478 }
 479
 480 static void tun_flow_cleanup(struct timer_list *t)
 481 {
 482         struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
 483         unsigned long delay = tun->ageing_time;
 484         unsigned long next_timer = jiffies + delay;
 485         unsigned long count = 0;
 486         int i;
 487
 488         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 489
 490         spin_lock(&tun->lock);
 491         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 492                 struct tun_flow_entry *e;
 493                 struct hlist_node *n;
 494
 495                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 496                         unsigned long this_timer;
 497
 498                         this_timer = e->updated + delay;
 499                         if (time_before_eq(this_timer, jiffies)) {
 500                                 tun_flow_delete(tun, e);
 501                                 continue;
 502                         }
 503                         count++;
 504                         if (time_before(this_timer, next_timer))
 505                                 next_timer = this_timer;
 506                 }
 507         }
 508
 509         if (count)
 510                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 511         spin_unlock(&tun->lock);
 512 }
 513
 514 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 515                             struct tun_file *tfile)
 516 {
 517         struct hlist_head *head;
 518         struct tun_flow_entry *e;
 519         unsigned long delay = tun->ageing_time;
 520         u16 queue_index = tfile->queue_index;
 521
 522         head = &tun->flows[tun_hashfn(rxhash)];
 523
 524         rcu_read_lock();
 525
 526         e = tun_flow_find(head, rxhash);
 527         if (likely(e)) {
 528                 /* TODO: keep queueing to old queue until it's empty? */
 529                 if (READ_ONCE(e->queue_index) != queue_index)
 530                         WRITE_ONCE(e->queue_index, queue_index);
 531                 if (e->updated != jiffies)
 532                         e->updated = jiffies;
 533                 sock_rps_record_flow_hash(e->rps_rxhash);
 534         } else {
 535                 spin_lock_bh(&tun->lock);
 536                 if (!tun_flow_find(head, rxhash) &&
 537                     tun->flow_count < MAX_TAP_FLOWS)
 538                         tun_flow_create(tun, head, rxhash, queue_index);
 539
 540                 if (!timer_pending(&tun->flow_gc_timer))
 541                         mod_timer(&tun->flow_gc_timer,
 542                                   round_jiffies_up(jiffies + delay));
 543                 spin_unlock_bh(&tun->lock);
 544         }
 545
 546         rcu_read_unlock();
 547 }
 548
 549 /**
 550  * Save the hash received in the stack receive path and update the
 551  * flow_hash table accordingly.
 552  */
 553 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
 554 {
 555         if (unlikely(e->rps_rxhash != hash))
 556                 e->rps_rxhash = hash;
 557 }
 558
 559 /* We try to identify a flow through its rxhash. The reason that
 560  * we do not check rxq no. is because some cards(e.g 82599), chooses
 561  * the rxq based on the txq where the last packet of the flow comes. As
 562  * the userspace application move between processors, we may get a
 563  * different rxq no. here.
 564  */
 565 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 566 {
 567         struct tun_flow_entry *e;
 568         u32 txq = 0;
 569         u32 numqueues = 0;
 570
 571         numqueues = READ_ONCE(tun->numqueues);
 572
 573         txq = __skb_get_hash_symmetric(skb);
 574         e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 575         if (e) {
 576                 tun_flow_save_rps_rxhash(e, txq);
 577                 txq = e->queue_index;
 578         } else {
 579                 /* use multiply and shift instead of expensive divide */
 580                 txq = ((u64)txq * numqueues) >> 32;
 581         }
 582
 583         return txq;
 584 }
 585
 586 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 587 {
 588         struct tun_prog *prog;
 589         u32 numqueues;
 590         u16 ret = 0;
 591
 592         numqueues = READ_ONCE(tun->numqueues);
 593         if (!numqueues)
 594                 return 0;
 595
 596         prog = rcu_dereference(tun->steering_prog);
 597         if (prog)
 598                 ret = bpf_prog_run_clear_cb(prog->prog, skb);
 599
 600         return ret % numqueues;
 601 }
 602
 603 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
 604                             struct net_device *sb_dev)
 605 {
 606         struct tun_struct *tun = netdev_priv(dev);
 607         u16 ret;
 608
 609         rcu_read_lock();
 610         if (rcu_dereference(tun->steering_prog))
 611                 ret = tun_ebpf_select_queue(tun, skb);
 612         else
 613                 ret = tun_automq_select_queue(tun, skb);
 614         rcu_read_unlock();
 615
 616         return ret;
 617 }
 618
 619 static inline bool tun_not_capable(struct tun_struct *tun)
 620 {
 621         const struct cred *cred = current_cred();
 622         struct net *net = dev_net(tun->dev);
 623
 624         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 625                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 626                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 627 }
 628
 629 static void tun_set_real_num_queues(struct tun_struct *tun)
 630 {
 631         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 632         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 633 }
 634
 635 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 636 {
 637         tfile->detached = tun;
 638         list_add_tail(&tfile->next, &tun->disabled);
 639         ++tun->numdisabled;
 640 }
 641
 642 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 643 {
 644         struct tun_struct *tun = tfile->detached;
 645
 646         tfile->detached = NULL;
 647         list_del_init(&tfile->next);
 648         --tun->numdisabled;
 649         return tun;
 650 }
 651
 652 void tun_ptr_free(void *ptr)
 653 {
 654         if (!ptr)
 655                 return;
 656         if (tun_is_xdp_frame(ptr)) {
 657                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
 658
 659                 xdp_return_frame(xdpf);
 660         } else {
 661                 __skb_array_destroy_skb(ptr);
 662         }
 663 }
 664 EXPORT_SYMBOL_GPL(tun_ptr_free);
 665
 666 static void tun_queue_purge(struct tun_file *tfile)
 667 {
 668         void *ptr;
 669
 670         while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
 671                 tun_ptr_free(ptr);
 672
 673         skb_queue_purge(&tfile->sk.sk_write_queue);
 674         skb_queue_purge(&tfile->sk.sk_error_queue);
 675 }
 676
 677 static void __tun_detach(struct tun_file *tfile, bool clean)
 678 {
 679         struct tun_file *ntfile;
 680         struct tun_struct *tun;
 681
 682         tun = rtnl_dereference(tfile->tun);
 683
 684         if (tun && clean) {
 685                 tun_napi_disable(tfile);
 686                 tun_napi_del(tfile);
 687         }
 688
 689         if (tun && !tfile->detached) {
 690                 u16 index = tfile->queue_index;
 691                 BUG_ON(index >= tun->numqueues);
 692
 693                 rcu_assign_pointer(tun->tfiles[index],
 694                                    tun->tfiles[tun->numqueues - 1]);
 695                 ntfile = rtnl_dereference(tun->tfiles[index]);
 696                 ntfile->queue_index = index;
 697                 rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
 698                                    NULL);
 699
 700                 --tun->numqueues;
 701                 if (clean) {
 702                         RCU_INIT_POINTER(tfile->tun, NULL);
 703                         sock_put(&tfile->sk);
 704                 } else
 705                         tun_disable_queue(tun, tfile);
 706
 707                 synchronize_net();
 708                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 709                 /* Drop read queue */
 710                 tun_queue_purge(tfile);
 711                 tun_set_real_num_queues(tun);
 712         } else if (tfile->detached && clean) {
 713                 tun = tun_enable_queue(tfile);
 714                 sock_put(&tfile->sk);
 715         }
 716
 717         if (clean) {
 718                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 719                         netif_carrier_off(tun->dev);
 720
 721                         if (!(tun->flags & IFF_PERSIST) &&
 722                             tun->dev->reg_state == NETREG_REGISTERED)
 723                                 unregister_netdevice(tun->dev);
 724                 }
 725                 if (tun)
 726                         xdp_rxq_info_unreg(&tfile->xdp_rxq);
 727                 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
 728                 sock_put(&tfile->sk);
 729         }
 730 }
 731
 732 static void tun_detach(struct tun_file *tfile, bool clean)
 733 {
 734         struct tun_struct *tun;
 735         struct net_device *dev;
 736
 737         rtnl_lock();
 738         tun = rtnl_dereference(tfile->tun);
 739         dev = tun ? tun->dev : NULL;
 740         __tun_detach(tfile, clean);
 741         if (dev)
 742                 netdev_state_change(dev);
 743         rtnl_unlock();
 744 }
 745
 746 static void tun_detach_all(struct net_device *dev)
 747 {
 748         struct tun_struct *tun = netdev_priv(dev);
 749         struct tun_file *tfile, *tmp;
 750         int i, n = tun->numqueues;
 751
 752         for (i = 0; i < n; i++) {
 753                 tfile = rtnl_dereference(tun->tfiles[i]);
 754                 BUG_ON(!tfile);
 755                 tun_napi_disable(tfile);
 756                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 757                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 758                 RCU_INIT_POINTER(tfile->tun, NULL);
 759                 --tun->numqueues;
 760         }
 761         list_for_each_entry(tfile, &tun->disabled, next) {
 762                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 763                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 764                 RCU_INIT_POINTER(tfile->tun, NULL);
 765         }
 766         BUG_ON(tun->numqueues != 0);
 767
 768         synchronize_net();
 769         for (i = 0; i < n; i++) {
 770                 tfile = rtnl_dereference(tun->tfiles[i]);
 771                 tun_napi_del(tfile);
 772                 /* Drop read queue */
 773                 tun_queue_purge(tfile);
 774                 xdp_rxq_info_unreg(&tfile->xdp_rxq);
 775                 sock_put(&tfile->sk);
 776         }
 777         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 778                 tun_enable_queue(tfile);
 779                 tun_queue_purge(tfile);
 780                 xdp_rxq_info_unreg(&tfile->xdp_rxq);
 781                 sock_put(&tfile->sk);
 782         }
 783         BUG_ON(tun->numdisabled != 0);
 784
 785         if (tun->flags & IFF_PERSIST)
 786                 module_put(THIS_MODULE);
 787 }
 788
 789 static int tun_attach(struct tun_struct *tun, struct file *file,
 790                       bool skip_filter, bool napi, bool napi_frags,
 791                       bool publish_tun)
 792 {
 793         struct tun_file *tfile = file->private_data;
 794         struct net_device *dev = tun->dev;
 795         int err;
 796
 797         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 798         if (err < 0)
 799                 goto out;
 800
 801         err = -EINVAL;
 802         if (rtnl_dereference(tfile->tun) && !tfile->detached)
 803                 goto out;
 804
 805         err = -EBUSY;
 806         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
 807                 goto out;
 808
 809         err = -E2BIG;
 810         if (!tfile->detached &&
 811             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 812                 goto out;
 813
 814         err = 0;
 815
 816         /* Re-attach the filter to persist device */
 817         if (!skip_filter && (tun->filter_attached == true)) {
 818                 lock_sock(tfile->socket.sk);
 819                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 820                 release_sock(tfile->socket.sk);
 821                 if (!err)
 822                         goto out;
 823         }
 824
 825         if (!tfile->detached &&
 826             ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
 827                             GFP_KERNEL, tun_ptr_free)) {
 828                 err = -ENOMEM;
 829                 goto out;
 830         }
 831
 832         tfile->queue_index = tun->numqueues;
 833         tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
 834
 835         if (tfile->detached) {
 836                 /* Re-attach detached tfile, updating XDP queue_index */
 837                 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
 838
 839                 if (tfile->xdp_rxq.queue_index    != tfile->queue_index)
 840                         tfile->xdp_rxq.queue_index = tfile->queue_index;
 841         } else {
 842                 /* Setup XDP RX-queue info, for new tfile getting attached */
 843                 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
 844                                        tun->dev, tfile->queue_index);
 845                 if (err < 0)
 846                         goto out;
 847                 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
 848                                                  MEM_TYPE_PAGE_SHARED, NULL);
 849                 if (err < 0) {
 850                         xdp_rxq_info_unreg(&tfile->xdp_rxq);
 851                         goto out;
 852                 }
 853                 err = 0;
 854         }
 855
 856         if (tfile->detached) {
 857                 tun_enable_queue(tfile);
 858         } else {
 859                 sock_hold(&tfile->sk);
 860                 tun_napi_init(tun, tfile, napi, napi_frags);
 861         }
 862
 863         if (rtnl_dereference(tun->xdp_prog))
 864                 sock_set_flag(&tfile->sk, SOCK_XDP);
 865
 866         /* device is allowed to go away first, so no need to hold extra
 867          * refcnt.
 868          */
 869
 870         /* Publish tfile->tun and tun->tfiles only after we've fully
 871          * initialized tfile; otherwise we risk using half-initialized
 872          * object.
 873          */
 874         if (publish_tun)
 875                 rcu_assign_pointer(tfile->tun, tun);
 876         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 877         tun->numqueues++;
 878         tun_set_real_num_queues(tun);
 879 out:
 880         return err;
 881 }
 882
 883 static struct tun_struct *tun_get(struct tun_file *tfile)
 884 {
 885         struct tun_struct *tun;
 886
 887         rcu_read_lock();
 888         tun = rcu_dereference(tfile->tun);
 889         if (tun)
 890                 dev_hold(tun->dev);
 891         rcu_read_unlock();
 892
 893         return tun;
 894 }
 895
 896 static void tun_put(struct tun_struct *tun)
 897 {
 898         dev_put(tun->dev);
 899 }
 900
 901 /* TAP filtering */
 902 static void addr_hash_set(u32 *mask, const u8 *addr)
 903 {
 904         int n = ether_crc(ETH_ALEN, addr) >> 26;
 905         mask[n >> 5] |= (1 << (n & 31));
 906 }
 907
 908 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 909 {
 910         int n = ether_crc(ETH_ALEN, addr) >> 26;
 911         return mask[n >> 5] & (1 << (n & 31));
 912 }
 913
 914 static int update_filter(struct tap_filter *filter, void __user *arg)
 915 {
 916         struct { u8 u[ETH_ALEN]; } *addr;
 917         struct tun_filter uf;
 918         int err, alen, n, nexact;
 919
 920         if (copy_from_user(&uf, arg, sizeof(uf)))
 921                 return -EFAULT;
 922
 923         if (!uf.count) {
 924                 /* Disabled */
 925                 filter->count = 0;
 926                 return 0;
 927         }
 928
 929         alen = ETH_ALEN * uf.count;
 930         addr = memdup_user(arg + sizeof(uf), alen);
 931         if (IS_ERR(addr))
 932                 return PTR_ERR(addr);
 933
 934         /* The filter is updated without holding any locks. Which is
 935          * perfectly safe. We disable it first and in the worst
 936          * case we'll accept a few undesired packets. */
 937         filter->count = 0;
 938         wmb();
 939
 940         /* Use first set of addresses as an exact filter */
 941         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 942                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 943
 944         nexact = n;
 945
 946         /* Remaining multicast addresses are hashed,
 947          * unicast will leave the filter disabled. */
 948         memset(filter->mask, 0, sizeof(filter->mask));
 949         for (; n < uf.count; n++) {
 950                 if (!is_multicast_ether_addr(addr[n].u)) {
 951                         err = 0; /* no filter */
 952                         goto free_addr;
 953                 }
 954                 addr_hash_set(filter->mask, addr[n].u);
 955         }
 956
 957         /* For ALLMULTI just set the mask to all ones.
 958          * This overrides the mask populated above. */
 959         if ((uf.flags & TUN_FLT_ALLMULTI))
 960                 memset(filter->mask, ~0, sizeof(filter->mask));
 961
 962         /* Now enable the filter */
 963         wmb();
 964         filter->count = nexact;
 965
 966         /* Return the number of exact filters */
 967         err = nexact;
 968 free_addr:
 969         kfree(addr);
 970         return err;
 971 }
 972
 973 /* Returns: 0 - drop, !=0 - accept */
 974 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 975 {
 976         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 977          * at this point. */
 978         struct ethhdr *eh = (struct ethhdr *) skb->data;
 979         int i;
 980
 981         /* Exact match */
 982         for (i = 0; i < filter->count; i++)
 983                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 984                         return 1;
 985
 986         /* Inexact match (multicast only) */
 987         if (is_multicast_ether_addr(eh->h_dest))
 988                 return addr_hash_test(filter->mask, eh->h_dest);
 989
 990         return 0;
 991 }
 992
 993 /*
 994  * Checks whether the packet is accepted or not.
 995  * Returns: 0 - drop, !=0 - accept
 996  */
 997 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 998 {
 999         if (!filter->count)
1000                 return 1;
1001
1002         return run_filter(filter, skb);
1003 }
1004
1005 /* Network device part of the driver */
1006
1007 static const struct ethtool_ops tun_ethtool_ops;
1008
1009 /* Net device detach from fd. */
1010 static void tun_net_uninit(struct net_device *dev)
1011 {
1012         tun_detach_all(dev);
1013 }
1014
1015 /* Net device open. */
1016 static int tun_net_open(struct net_device *dev)
1017 {
1018         netif_tx_start_all_queues(dev);
1019
1020         return 0;
1021 }
1022
1023 /* Net device close. */
1024 static int tun_net_close(struct net_device *dev)
1025 {
1026         netif_tx_stop_all_queues(dev);
1027         return 0;
1028 }
1029
1030 /* Net device start xmit */
1031 static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1032 {
1033 #ifdef CONFIG_RPS
1034         if (tun->numqueues == 1 && static_branch_unlikely(&rps_needed)) {
1035                 /* Select queue was not called for the skbuff, so we extract the
1036                  * RPS hash and save it into the flow_table here.
1037                  */
1038                 struct tun_flow_entry *e;
1039                 __u32 rxhash;
1040
1041                 rxhash = __skb_get_hash_symmetric(skb);
1042                 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
1043                 if (e)
1044                         tun_flow_save_rps_rxhash(e, rxhash);
1045         }
1046 #endif
1047 }
1048
1049 static unsigned int run_ebpf_filter(struct tun_struct *tun,
1050                                     struct sk_buff *skb,
1051                                     int len)
1052 {
1053         struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1054
1055         if (prog)
1056                 len = bpf_prog_run_clear_cb(prog->prog, skb);
1057
1058         return len;
1059 }
1060
1061 /* Net device start xmit */
1062 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1063 {
1064         struct tun_struct *tun = netdev_priv(dev);
1065         int txq = skb->queue_mapping;
1066         struct tun_file *tfile;
1067         int len = skb->len;
1068
1069         rcu_read_lock();
1070         tfile = rcu_dereference(tun->tfiles[txq]);
1071
1072         /* Drop packet if interface is not attached */
1073         if (!tfile)
1074                 goto drop;
1075
1076         if (!rcu_dereference(tun->steering_prog))
1077                 tun_automq_xmit(tun, skb);
1078
1079         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
1080
1081         BUG_ON(!tfile);
1082
1083         /* Drop if the filter does not like it.
1084          * This is a noop if the filter is disabled.
1085          * Filter can be enabled only for the TAP devices. */
1086         if (!check_filter(&tun->txflt, skb))
1087                 goto drop;
1088
1089         if (tfile->socket.sk->sk_filter &&
1090             sk_filter(tfile->socket.sk, skb))
1091                 goto drop;
1092
1093         len = run_ebpf_filter(tun, skb, len);
1094         if (len == 0 || pskb_trim(skb, len))
1095                 goto drop;
1096
1097         if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1098                 goto drop;
1099
1100         skb_tx_timestamp(skb);
1101
1102         /* Orphan the skb - required as we might hang on to it
1103          * for indefinite time.
1104          */
1105         skb_orphan(skb);
1106
1107         nf_reset_ct(skb);
1108
1109         if (ptr_ring_produce(&tfile->tx_ring, skb))
1110                 goto drop;
1111
1112         /* Notify and wake up reader process */
1113         if (tfile->flags & TUN_FASYNC)
1114                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1115         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1116
1117         rcu_read_unlock();
1118         return NETDEV_TX_OK;
1119
1120 drop:
1121         this_cpu_inc(tun->pcpu_stats->tx_dropped);
1122         skb_tx_error(skb);
1123         kfree_skb(skb);
1124         rcu_read_unlock();
1125         return NET_XMIT_DROP;
1126 }
1127
1128 static void tun_net_mclist(struct net_device *dev)
1129 {
1130         /*
1131          * This callback is supposed to deal with mc filter in
1132          * _rx_ path and has nothing to do with the _tx_ path.
1133          * In rx path we always accept everything userspace gives us.
1134          */
1135 }
1136
1137 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1138         netdev_features_t features)
1139 {
1140         struct tun_struct *tun = netdev_priv(dev);
1141
1142         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1143 }
1144
1145 static void tun_set_headroom(struct net_device *dev, int new_hr)
1146 {
1147         struct tun_struct *tun = netdev_priv(dev);
1148
1149         if (new_hr < NET_SKB_PAD)
1150                 new_hr = NET_SKB_PAD;
1151
1152         tun->align = new_hr;
1153 }
1154
1155 static void
1156 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1157 {
1158         u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1159         struct tun_struct *tun = netdev_priv(dev);
1160         struct tun_pcpu_stats *p;
1161         int i;
1162
1163         for_each_possible_cpu(i) {
1164                 u64 rxpackets, rxbytes, txpackets, txbytes;
1165                 unsigned int start;
1166
1167                 p = per_cpu_ptr(tun->pcpu_stats, i);
1168                 do {
1169                         start = u64_stats_fetch_begin(&p->syncp);
1170                         rxpackets       = p->rx_packets;
1171                         rxbytes         = p->rx_bytes;
1172                         txpackets       = p->tx_packets;
1173                         txbytes         = p->tx_bytes;
1174                 } while (u64_stats_fetch_retry(&p->syncp, start));
1175
1176                 stats->rx_packets       += rxpackets;
1177                 stats->rx_bytes         += rxbytes;
1178                 stats->tx_packets       += txpackets;
1179                 stats->tx_bytes         += txbytes;
1180
1181                 /* u32 counters */
1182                 rx_dropped      += p->rx_dropped;
1183                 rx_frame_errors += p->rx_frame_errors;
1184                 tx_dropped      += p->tx_dropped;
1185         }
1186         stats->rx_dropped  = rx_dropped;
1187         stats->rx_frame_errors = rx_frame_errors;
1188         stats->tx_dropped = tx_dropped;
1189 }
1190
1191 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1192                        struct netlink_ext_ack *extack)
1193 {
1194         struct tun_struct *tun = netdev_priv(dev);
1195         struct tun_file *tfile;
1196         struct bpf_prog *old_prog;
1197         int i;
1198
1199         old_prog = rtnl_dereference(tun->xdp_prog);
1200         rcu_assign_pointer(tun->xdp_prog, prog);
1201         if (old_prog)
1202                 bpf_prog_put(old_prog);
1203
1204         for (i = 0; i < tun->numqueues; i++) {
1205                 tfile = rtnl_dereference(tun->tfiles[i]);
1206                 if (prog)
1207                         sock_set_flag(&tfile->sk, SOCK_XDP);
1208                 else
1209                         sock_reset_flag(&tfile->sk, SOCK_XDP);
1210         }
1211         list_for_each_entry(tfile, &tun->disabled, next) {
1212                 if (prog)
1213                         sock_set_flag(&tfile->sk, SOCK_XDP);
1214                 else
1215                         sock_reset_flag(&tfile->sk, SOCK_XDP);
1216         }
1217
1218         return 0;
1219 }
1220
1221 static u32 tun_xdp_query(struct net_device *dev)
1222 {
1223         struct tun_struct *tun = netdev_priv(dev);
1224         const struct bpf_prog *xdp_prog;
1225
1226         xdp_prog = rtnl_dereference(tun->xdp_prog);
1227         if (xdp_prog)
1228                 return xdp_prog->aux->id;
1229
1230         return 0;
1231 }
1232
1233 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1234 {
1235         switch (xdp->command) {
1236         case XDP_SETUP_PROG:
1237                 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1238         case XDP_QUERY_PROG:
1239                 xdp->prog_id = tun_xdp_query(dev);
1240                 return 0;
1241         default:
1242                 return -EINVAL;
1243         }
1244 }
1245
1246 static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1247 {
1248         if (new_carrier) {
1249                 struct tun_struct *tun = netdev_priv(dev);
1250
1251                 if (!tun->numqueues)
1252                         return -EPERM;
1253
1254                 netif_carrier_on(dev);
1255         } else {
1256                 netif_carrier_off(dev);
1257         }
1258         return 0;
1259 }
1260
1261 static const struct net_device_ops tun_netdev_ops = {
1262         .ndo_uninit             = tun_net_uninit,
1263         .ndo_open               = tun_net_open,
1264         .ndo_stop               = tun_net_close,
1265         .ndo_start_xmit         = tun_net_xmit,
1266         .ndo_fix_features       = tun_net_fix_features,
1267         .ndo_select_queue       = tun_select_queue,
1268         .ndo_set_rx_headroom    = tun_set_headroom,
1269         .ndo_get_stats64        = tun_net_get_stats64,
1270         .ndo_change_carrier     = tun_net_change_carrier,
1271 };
1272
1273 static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1274 {
1275         /* Notify and wake up reader process */
1276         if (tfile->flags & TUN_FASYNC)
1277                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1278         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1279 }
1280
1281 static int tun_xdp_xmit(struct net_device *dev, int n,
1282                         struct xdp_frame **frames, u32 flags)
1283 {
1284         struct tun_struct *tun = netdev_priv(dev);
1285         struct tun_file *tfile;
1286         u32 numqueues;
1287         int drops = 0;
1288         int cnt = n;
1289         int i;
1290
1291         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1292                 return -EINVAL;
1293
1294         rcu_read_lock();
1295
1296 resample:
1297         numqueues = READ_ONCE(tun->numqueues);
1298         if (!numqueues) {
1299                 rcu_read_unlock();
1300                 return -ENXIO; /* Caller will free/return all frames */
1301         }
1302
1303         tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1304                                             numqueues]);
1305         if (unlikely(!tfile))
1306                 goto resample;
1307
1308         spin_lock(&tfile->tx_ring.producer_lock);
1309         for (i = 0; i < n; i++) {
1310                 struct xdp_frame *xdp = frames[i];
1311                 /* Encode the XDP flag into lowest bit for consumer to differ
1312                  * XDP buffer from sk_buff.
1313                  */
1314                 void *frame = tun_xdp_to_ptr(xdp);
1315
1316                 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1317                         this_cpu_inc(tun->pcpu_stats->tx_dropped);
1318                         xdp_return_frame_rx_napi(xdp);
1319                         drops++;
1320                 }
1321         }
1322         spin_unlock(&tfile->tx_ring.producer_lock);
1323
1324         if (flags & XDP_XMIT_FLUSH)
1325                 __tun_xdp_flush_tfile(tfile);
1326
1327         rcu_read_unlock();
1328         return cnt - drops;
1329 }
1330
1331 static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1332 {
1333         struct xdp_frame *frame = convert_to_xdp_frame(xdp);
1334
1335         if (unlikely(!frame))
1336                 return -EOVERFLOW;
1337
1338         return tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1339 }
1340
1341 static const struct net_device_ops tap_netdev_ops = {
1342         .ndo_uninit             = tun_net_uninit,
1343         .ndo_open               = tun_net_open,
1344         .ndo_stop               = tun_net_close,
1345         .ndo_start_xmit         = tun_net_xmit,
1346         .ndo_fix_features       = tun_net_fix_features,
1347         .ndo_set_rx_mode        = tun_net_mclist,
1348         .ndo_set_mac_address    = eth_mac_addr,
1349         .ndo_validate_addr      = eth_validate_addr,
1350         .ndo_select_queue       = tun_select_queue,
1351         .ndo_features_check     = passthru_features_check,
1352         .ndo_set_rx_headroom    = tun_set_headroom,
1353         .ndo_get_stats64        = tun_net_get_stats64,
1354         .ndo_bpf                = tun_xdp,
1355         .ndo_xdp_xmit           = tun_xdp_xmit,
1356         .ndo_change_carrier     = tun_net_change_carrier,
1357 };
1358
1359 static void tun_flow_init(struct tun_struct *tun)
1360 {
1361         int i;
1362
1363         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1364                 INIT_HLIST_HEAD(&tun->flows[i]);
1365
1366         tun->ageing_time = TUN_FLOW_EXPIRE;
1367         timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1368         mod_timer(&tun->flow_gc_timer,
1369                   round_jiffies_up(jiffies + tun->ageing_time));
1370 }
1371
1372 static void tun_flow_uninit(struct tun_struct *tun)
1373 {
1374         del_timer_sync(&tun->flow_gc_timer);
1375         tun_flow_flush(tun);
1376 }
1377
1378 #define MIN_MTU 68
1379 #define MAX_MTU 65535
1380
1381 /* Initialize net device. */
1382 static void tun_net_init(struct net_device *dev)
1383 {
1384         struct tun_struct *tun = netdev_priv(dev);
1385
1386         switch (tun->flags & TUN_TYPE_MASK) {
1387         case IFF_TUN:
1388                 dev->netdev_ops = &tun_netdev_ops;
1389
1390                 /* Point-to-Point TUN Device */
1391                 dev->hard_header_len = 0;
1392                 dev->addr_len = 0;
1393                 dev->mtu = 1500;
1394
1395                 /* Zero header length */
1396                 dev->type = ARPHRD_NONE;
1397                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1398                 break;
1399
1400         case IFF_TAP:
1401                 dev->netdev_ops = &tap_netdev_ops;
1402                 /* Ethernet TAP Device */
1403                 ether_setup(dev);
1404                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1405                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1406
1407                 eth_hw_addr_random(dev);
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         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1439
1440         poll_wait(file, sk_sleep(sk), wait);
1441
1442         if (!ptr_ring_empty(&tfile->tx_ring))
1443                 mask |= EPOLLIN | EPOLLRDNORM;
1444
1445         /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1446          * guarantee EPOLLOUT to be raised by either here or
1447          * tun_sock_write_space(). Then process could get notification
1448          * after it writes to a down device and meets -EIO.
1449          */
1450         if (tun_sock_writeable(tun, tfile) ||
1451             (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1452              tun_sock_writeable(tun, tfile)))
1453                 mask |= EPOLLOUT | EPOLLWRNORM;
1454
1455         if (tun->dev->reg_state != NETREG_REGISTERED)
1456                 mask = EPOLLERR;
1457
1458         tun_put(tun);
1459         return mask;
1460 }
1461
1462 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1463                                             size_t len,
1464                                             const struct iov_iter *it)
1465 {
1466         struct sk_buff *skb;
1467         size_t linear;
1468         int err;
1469         int i;
1470
1471         if (it->nr_segs > MAX_SKB_FRAGS + 1)
1472                 return ERR_PTR(-ENOMEM);
1473
1474         local_bh_disable();
1475         skb = napi_get_frags(&tfile->napi);
1476         local_bh_enable();
1477         if (!skb)
1478                 return ERR_PTR(-ENOMEM);
1479
1480         linear = iov_iter_single_seg_count(it);
1481         err = __skb_grow(skb, linear);
1482         if (err)
1483                 goto free;
1484
1485         skb->len = len;
1486         skb->data_len = len - linear;
1487         skb->truesize += skb->data_len;
1488
1489         for (i = 1; i < it->nr_segs; i++) {
1490                 size_t fragsz = it->iov[i].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(act);
1643                 /* fall through */
1644         case XDP_ABORTED:
1645                 trace_xdp_exception(tun->dev, xdp_prog, act);
1646                 /* fall through */
1647         case XDP_DROP:
1648                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
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.data_hard_start = buf;
1707                 xdp.data = buf + pad;
1708                 xdp_set_data_meta_invalid(&xdp);
1709                 xdp.data_end = xdp.data + len;
1710                 xdp.rxq = &tfile->xdp_rxq;
1711
1712                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1713                 if (act == XDP_REDIRECT || act == XDP_TX) {
1714                         get_page(alloc_frag->page);
1715                         alloc_frag->offset += buflen;
1716                 }
1717                 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1718                 if (err < 0)
1719                         goto err_xdp;
1720                 if (err == XDP_REDIRECT)
1721                         xdp_do_flush_map();
1722                 if (err != XDP_PASS)
1723                         goto out;
1724
1725                 pad = xdp.data - xdp.data_hard_start;
1726                 len = xdp.data_end - xdp.data;
1727         }
1728         rcu_read_unlock();
1729         local_bh_enable();
1730
1731         return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1732
1733 err_xdp:
1734         put_page(alloc_frag->page);
1735 out:
1736         rcu_read_unlock();
1737         local_bh_enable();
1738         return NULL;
1739 }
1740
1741 /* Get packet from user space buffer */
1742 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1743                             void *msg_control, struct iov_iter *from,
1744                             int noblock, bool more)
1745 {
1746         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1747         struct sk_buff *skb;
1748         size_t total_len = iov_iter_count(from);
1749         size_t len = total_len, align = tun->align, linear;
1750         struct virtio_net_hdr gso = { 0 };
1751         struct tun_pcpu_stats *stats;
1752         int good_linear;
1753         int copylen;
1754         bool zerocopy = false;
1755         int err;
1756         u32 rxhash = 0;
1757         int skb_xdp = 1;
1758         bool frags = tun_napi_frags_enabled(tfile);
1759
1760         if (!(tun->flags & IFF_NO_PI)) {
1761                 if (len < sizeof(pi))
1762                         return -EINVAL;
1763                 len -= sizeof(pi);
1764
1765                 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1766                         return -EFAULT;
1767         }
1768
1769         if (tun->flags & IFF_VNET_HDR) {
1770                 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1771
1772                 if (len < vnet_hdr_sz)
1773                         return -EINVAL;
1774                 len -= vnet_hdr_sz;
1775
1776                 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1777                         return -EFAULT;
1778
1779                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1780                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1781                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1782
1783                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1784                         return -EINVAL;
1785                 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1786         }
1787
1788         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1789                 align += NET_IP_ALIGN;
1790                 if (unlikely(len < ETH_HLEN ||
1791                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1792                         return -EINVAL;
1793         }
1794
1795         good_linear = SKB_MAX_HEAD(align);
1796
1797         if (msg_control) {
1798                 struct iov_iter i = *from;
1799
1800                 /* There are 256 bytes to be copied in skb, so there is
1801                  * enough room for skb expand head in case it is used.
1802                  * The rest of the buffer is mapped from userspace.
1803                  */
1804                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1805                 if (copylen > good_linear)
1806                         copylen = good_linear;
1807                 linear = copylen;
1808                 iov_iter_advance(&i, copylen);
1809                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1810                         zerocopy = true;
1811         }
1812
1813         if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1814                 /* For the packet that is not easy to be processed
1815                  * (e.g gso or jumbo packet), we will do it at after
1816                  * skb was created with generic XDP routine.
1817                  */
1818                 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1819                 if (IS_ERR(skb)) {
1820                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1821                         return PTR_ERR(skb);
1822                 }
1823                 if (!skb)
1824                         return total_len;
1825         } else {
1826                 if (!zerocopy) {
1827                         copylen = len;
1828                         if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1829                                 linear = good_linear;
1830                         else
1831                                 linear = tun16_to_cpu(tun, gso.hdr_len);
1832                 }
1833
1834                 if (frags) {
1835                         mutex_lock(&tfile->napi_mutex);
1836                         skb = tun_napi_alloc_frags(tfile, copylen, from);
1837                         /* tun_napi_alloc_frags() enforces a layout for the skb.
1838                          * If zerocopy is enabled, then this layout will be
1839                          * overwritten by zerocopy_sg_from_iter().
1840                          */
1841                         zerocopy = false;
1842                 } else {
1843                         skb = tun_alloc_skb(tfile, align, copylen, linear,
1844                                             noblock);
1845                 }
1846
1847                 if (IS_ERR(skb)) {
1848                         if (PTR_ERR(skb) != -EAGAIN)
1849                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1850                         if (frags)
1851                                 mutex_unlock(&tfile->napi_mutex);
1852                         return PTR_ERR(skb);
1853                 }
1854
1855                 if (zerocopy)
1856                         err = zerocopy_sg_from_iter(skb, from);
1857                 else
1858                         err = skb_copy_datagram_from_iter(skb, 0, from, len);
1859
1860                 if (err) {
1861                         err = -EFAULT;
1862 drop:
1863                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1864                         kfree_skb(skb);
1865                         if (frags) {
1866                                 tfile->napi.skb = NULL;
1867                                 mutex_unlock(&tfile->napi_mutex);
1868                         }
1869
1870                         return err;
1871                 }
1872         }
1873
1874         if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1875                 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1876                 kfree_skb(skb);
1877                 if (frags) {
1878                         tfile->napi.skb = NULL;
1879                         mutex_unlock(&tfile->napi_mutex);
1880                 }
1881
1882                 return -EINVAL;
1883         }
1884
1885         switch (tun->flags & TUN_TYPE_MASK) {
1886         case IFF_TUN:
1887                 if (tun->flags & IFF_NO_PI) {
1888                         u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1889
1890                         switch (ip_version) {
1891                         case 4:
1892                                 pi.proto = htons(ETH_P_IP);
1893                                 break;
1894                         case 6:
1895                                 pi.proto = htons(ETH_P_IPV6);
1896                                 break;
1897                         default:
1898                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1899                                 kfree_skb(skb);
1900                                 return -EINVAL;
1901                         }
1902                 }
1903
1904                 skb_reset_mac_header(skb);
1905                 skb->protocol = pi.proto;
1906                 skb->dev = tun->dev;
1907                 break;
1908         case IFF_TAP:
1909                 if (!frags)
1910                         skb->protocol = eth_type_trans(skb, tun->dev);
1911                 break;
1912         }
1913
1914         /* copy skb_ubuf_info for callback when skb has no error */
1915         if (zerocopy) {
1916                 skb_shinfo(skb)->destructor_arg = msg_control;
1917                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1918                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1919         } else if (msg_control) {
1920                 struct ubuf_info *uarg = msg_control;
1921                 uarg->callback(uarg, false);
1922         }
1923
1924         skb_reset_network_header(skb);
1925         skb_probe_transport_header(skb);
1926
1927         if (skb_xdp) {
1928                 struct bpf_prog *xdp_prog;
1929                 int ret;
1930
1931                 local_bh_disable();
1932                 rcu_read_lock();
1933                 xdp_prog = rcu_dereference(tun->xdp_prog);
1934                 if (xdp_prog) {
1935                         ret = do_xdp_generic(xdp_prog, skb);
1936                         if (ret != XDP_PASS) {
1937                                 rcu_read_unlock();
1938                                 local_bh_enable();
1939                                 return total_len;
1940                         }
1941                 }
1942                 rcu_read_unlock();
1943                 local_bh_enable();
1944         }
1945
1946         /* Compute the costly rx hash only if needed for flow updates.
1947          * We may get a very small possibility of OOO during switching, not
1948          * worth to optimize.
1949          */
1950         if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1951             !tfile->detached)
1952                 rxhash = __skb_get_hash_symmetric(skb);
1953
1954         rcu_read_lock();
1955         if (unlikely(!(tun->dev->flags & IFF_UP))) {
1956                 err = -EIO;
1957                 rcu_read_unlock();
1958                 goto drop;
1959         }
1960
1961         if (frags) {
1962                 /* Exercise flow dissector code path. */
1963                 u32 headlen = eth_get_headlen(tun->dev, skb->data,
1964                                               skb_headlen(skb));
1965
1966                 if (unlikely(headlen > skb_headlen(skb))) {
1967                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1968                         napi_free_frags(&tfile->napi);
1969                         rcu_read_unlock();
1970                         mutex_unlock(&tfile->napi_mutex);
1971                         WARN_ON(1);
1972                         return -ENOMEM;
1973                 }
1974
1975                 local_bh_disable();
1976                 napi_gro_frags(&tfile->napi);
1977                 local_bh_enable();
1978                 mutex_unlock(&tfile->napi_mutex);
1979         } else if (tfile->napi_enabled) {
1980                 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1981                 int queue_len;
1982
1983                 spin_lock_bh(&queue->lock);
1984                 __skb_queue_tail(queue, skb);
1985                 queue_len = skb_queue_len(queue);
1986                 spin_unlock(&queue->lock);
1987
1988                 if (!more || queue_len > NAPI_POLL_WEIGHT)
1989                         napi_schedule(&tfile->napi);
1990
1991                 local_bh_enable();
1992         } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1993                 tun_rx_batched(tun, tfile, skb, more);
1994         } else {
1995                 netif_rx_ni(skb);
1996         }
1997         rcu_read_unlock();
1998
1999         stats = get_cpu_ptr(tun->pcpu_stats);
2000         u64_stats_update_begin(&stats->syncp);
2001         stats->rx_packets++;
2002         stats->rx_bytes += len;
2003         u64_stats_update_end(&stats->syncp);
2004         put_cpu_ptr(stats);
2005
2006         if (rxhash)
2007                 tun_flow_update(tun, rxhash, tfile);
2008
2009         return total_len;
2010 }
2011
2012 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
2013 {
2014         struct file *file = iocb->ki_filp;
2015         struct tun_file *tfile = file->private_data;
2016         struct tun_struct *tun = tun_get(tfile);
2017         ssize_t result;
2018
2019         if (!tun)
2020                 return -EBADFD;
2021
2022         result = tun_get_user(tun, tfile, NULL, from,
2023                               file->f_flags & O_NONBLOCK, false);
2024
2025         tun_put(tun);
2026         return result;
2027 }
2028
2029 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2030                                 struct tun_file *tfile,
2031                                 struct xdp_frame *xdp_frame,
2032                                 struct iov_iter *iter)
2033 {
2034         int vnet_hdr_sz = 0;
2035         size_t size = xdp_frame->len;
2036         struct tun_pcpu_stats *stats;
2037         size_t ret;
2038
2039         if (tun->flags & IFF_VNET_HDR) {
2040                 struct virtio_net_hdr gso = { 0 };
2041
2042                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2043                 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2044                         return -EINVAL;
2045                 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2046                              sizeof(gso)))
2047                         return -EFAULT;
2048                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2049         }
2050
2051         ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2052
2053         stats = get_cpu_ptr(tun->pcpu_stats);
2054         u64_stats_update_begin(&stats->syncp);
2055         stats->tx_packets++;
2056         stats->tx_bytes += ret;
2057         u64_stats_update_end(&stats->syncp);
2058         put_cpu_ptr(tun->pcpu_stats);
2059
2060         return ret;
2061 }
2062
2063 /* Put packet to the user space buffer */
2064 static ssize_t tun_put_user(struct tun_struct *tun,
2065                             struct tun_file *tfile,
2066                             struct sk_buff *skb,
2067                             struct iov_iter *iter)
2068 {
2069         struct tun_pi pi = { 0, skb->protocol };
2070         struct tun_pcpu_stats *stats;
2071         ssize_t total;
2072         int vlan_offset = 0;
2073         int vlan_hlen = 0;
2074         int vnet_hdr_sz = 0;
2075
2076         if (skb_vlan_tag_present(skb))
2077                 vlan_hlen = VLAN_HLEN;
2078
2079         if (tun->flags & IFF_VNET_HDR)
2080                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2081
2082         total = skb->len + vlan_hlen + vnet_hdr_sz;
2083
2084         if (!(tun->flags & IFF_NO_PI)) {
2085                 if (iov_iter_count(iter) < sizeof(pi))
2086                         return -EINVAL;
2087
2088                 total += sizeof(pi);
2089                 if (iov_iter_count(iter) < total) {
2090                         /* Packet will be striped */
2091                         pi.flags |= TUN_PKT_STRIP;
2092                 }
2093
2094                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2095                         return -EFAULT;
2096         }
2097
2098         if (vnet_hdr_sz) {
2099                 struct virtio_net_hdr gso;
2100
2101                 if (iov_iter_count(iter) < vnet_hdr_sz)
2102                         return -EINVAL;
2103
2104                 if (virtio_net_hdr_from_skb(skb, &gso,
2105                                             tun_is_little_endian(tun), true,
2106                                             vlan_hlen)) {
2107                         struct skb_shared_info *sinfo = skb_shinfo(skb);
2108                         pr_err("unexpected GSO type: "
2109                                "0x%x, gso_size %d, hdr_len %d\n",
2110                                sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2111                                tun16_to_cpu(tun, gso.hdr_len));
2112                         print_hex_dump(KERN_ERR, "tun: ",
2113                                        DUMP_PREFIX_NONE,
2114                                        16, 1, skb->head,
2115                                        min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2116                         WARN_ON_ONCE(1);
2117                         return -EINVAL;
2118                 }
2119
2120                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2121                         return -EFAULT;
2122
2123                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2124         }
2125
2126         if (vlan_hlen) {
2127                 int ret;
2128                 struct veth veth;
2129
2130                 veth.h_vlan_proto = skb->vlan_proto;
2131                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2132
2133                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2134
2135                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2136                 if (ret || !iov_iter_count(iter))
2137                         goto done;
2138
2139                 ret = copy_to_iter(&veth, sizeof(veth), iter);
2140                 if (ret != sizeof(veth) || !iov_iter_count(iter))
2141                         goto done;
2142         }
2143
2144         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2145
2146 done:
2147         /* caller is in process context, */
2148         stats = get_cpu_ptr(tun->pcpu_stats);
2149         u64_stats_update_begin(&stats->syncp);
2150         stats->tx_packets++;
2151         stats->tx_bytes += skb->len + vlan_hlen;
2152         u64_stats_update_end(&stats->syncp);
2153         put_cpu_ptr(tun->pcpu_stats);
2154
2155         return total;
2156 }
2157
2158 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2159 {
2160         DECLARE_WAITQUEUE(wait, current);
2161         void *ptr = NULL;
2162         int error = 0;
2163
2164         ptr = ptr_ring_consume(&tfile->tx_ring);
2165         if (ptr)
2166                 goto out;
2167         if (noblock) {
2168                 error = -EAGAIN;
2169                 goto out;
2170         }
2171
2172         add_wait_queue(&tfile->socket.wq.wait, &wait);
2173
2174         while (1) {
2175                 set_current_state(TASK_INTERRUPTIBLE);
2176                 ptr = ptr_ring_consume(&tfile->tx_ring);
2177                 if (ptr)
2178                         break;
2179                 if (signal_pending(current)) {
2180                         error = -ERESTARTSYS;
2181                         break;
2182                 }
2183                 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2184                         error = -EFAULT;
2185                         break;
2186                 }
2187
2188                 schedule();
2189         }
2190
2191         __set_current_state(TASK_RUNNING);
2192         remove_wait_queue(&tfile->socket.wq.wait, &wait);
2193
2194 out:
2195         *err = error;
2196         return ptr;
2197 }
2198
2199 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2200                            struct iov_iter *to,
2201                            int noblock, void *ptr)
2202 {
2203         ssize_t ret;
2204         int err;
2205
2206         tun_debug(KERN_INFO, tun, "tun_do_read\n");
2207
2208         if (!iov_iter_count(to)) {
2209                 tun_ptr_free(ptr);
2210                 return 0;
2211         }
2212
2213         if (!ptr) {
2214                 /* Read frames from ring */
2215                 ptr = tun_ring_recv(tfile, noblock, &err);
2216                 if (!ptr)
2217                         return err;
2218         }
2219
2220         if (tun_is_xdp_frame(ptr)) {
2221                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2222
2223                 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2224                 xdp_return_frame(xdpf);
2225         } else {
2226                 struct sk_buff *skb = ptr;
2227
2228                 ret = tun_put_user(tun, tfile, skb, to);
2229                 if (unlikely(ret < 0))
2230                         kfree_skb(skb);
2231                 else
2232                         consume_skb(skb);
2233         }
2234
2235         return ret;
2236 }
2237
2238 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2239 {
2240         struct file *file = iocb->ki_filp;
2241         struct tun_file *tfile = file->private_data;
2242         struct tun_struct *tun = tun_get(tfile);
2243         ssize_t len = iov_iter_count(to), ret;
2244
2245         if (!tun)
2246                 return -EBADFD;
2247         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2248         ret = min_t(ssize_t, ret, len);
2249         if (ret > 0)
2250                 iocb->ki_pos = ret;
2251         tun_put(tun);
2252         return ret;
2253 }
2254
2255 static void tun_prog_free(struct rcu_head *rcu)
2256 {
2257         struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2258
2259         bpf_prog_destroy(prog->prog);
2260         kfree(prog);
2261 }
2262
2263 static int __tun_set_ebpf(struct tun_struct *tun,
2264                           struct tun_prog __rcu **prog_p,
2265                           struct bpf_prog *prog)
2266 {
2267         struct tun_prog *old, *new = NULL;
2268
2269         if (prog) {
2270                 new = kmalloc(sizeof(*new), GFP_KERNEL);
2271                 if (!new)
2272                         return -ENOMEM;
2273                 new->prog = prog;
2274         }
2275
2276         spin_lock_bh(&tun->lock);
2277         old = rcu_dereference_protected(*prog_p,
2278                                         lockdep_is_held(&tun->lock));
2279         rcu_assign_pointer(*prog_p, new);
2280         spin_unlock_bh(&tun->lock);
2281
2282         if (old)
2283                 call_rcu(&old->rcu, tun_prog_free);
2284
2285         return 0;
2286 }
2287
2288 static void tun_free_netdev(struct net_device *dev)
2289 {
2290         struct tun_struct *tun = netdev_priv(dev);
2291
2292         BUG_ON(!(list_empty(&tun->disabled)));
2293         free_percpu(tun->pcpu_stats);
2294         tun_flow_uninit(tun);
2295         security_tun_dev_free_security(tun->security);
2296         __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2297         __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2298 }
2299
2300 static void tun_setup(struct net_device *dev)
2301 {
2302         struct tun_struct *tun = netdev_priv(dev);
2303
2304         tun->owner = INVALID_UID;
2305         tun->group = INVALID_GID;
2306         tun_default_link_ksettings(dev, &tun->link_ksettings);
2307
2308         dev->ethtool_ops = &tun_ethtool_ops;
2309         dev->needs_free_netdev = true;
2310         dev->priv_destructor = tun_free_netdev;
2311         /* We prefer our own queue length */
2312         dev->tx_queue_len = TUN_READQ_SIZE;
2313 }
2314
2315 /* Trivial set of netlink ops to allow deleting tun or tap
2316  * device with netlink.
2317  */
2318 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2319                         struct netlink_ext_ack *extack)
2320 {
2321         NL_SET_ERR_MSG(extack,
2322                        "tun/tap creation via rtnetlink is not supported.");
2323         return -EOPNOTSUPP;
2324 }
2325
2326 static size_t tun_get_size(const struct net_device *dev)
2327 {
2328         BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2329         BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2330
2331         return nla_total_size(sizeof(uid_t)) + /* OWNER */
2332                nla_total_size(sizeof(gid_t)) + /* GROUP */
2333                nla_total_size(sizeof(u8)) + /* TYPE */
2334                nla_total_size(sizeof(u8)) + /* PI */
2335                nla_total_size(sizeof(u8)) + /* VNET_HDR */
2336                nla_total_size(sizeof(u8)) + /* PERSIST */
2337                nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2338                nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2339                nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2340                0;
2341 }
2342
2343 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2344 {
2345         struct tun_struct *tun = netdev_priv(dev);
2346
2347         if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2348                 goto nla_put_failure;
2349         if (uid_valid(tun->owner) &&
2350             nla_put_u32(skb, IFLA_TUN_OWNER,
2351                         from_kuid_munged(current_user_ns(), tun->owner)))
2352                 goto nla_put_failure;
2353         if (gid_valid(tun->group) &&
2354             nla_put_u32(skb, IFLA_TUN_GROUP,
2355                         from_kgid_munged(current_user_ns(), tun->group)))
2356                 goto nla_put_failure;
2357         if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2358                 goto nla_put_failure;
2359         if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2360                 goto nla_put_failure;
2361         if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2362                 goto nla_put_failure;
2363         if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2364                        !!(tun->flags & IFF_MULTI_QUEUE)))
2365                 goto nla_put_failure;
2366         if (tun->flags & IFF_MULTI_QUEUE) {
2367                 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2368                         goto nla_put_failure;
2369                 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2370                                 tun->numdisabled))
2371                         goto nla_put_failure;
2372         }
2373
2374         return 0;
2375
2376 nla_put_failure:
2377         return -EMSGSIZE;
2378 }
2379
2380 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2381         .kind           = DRV_NAME,
2382         .priv_size      = sizeof(struct tun_struct),
2383         .setup          = tun_setup,
2384         .validate       = tun_validate,
2385         .get_size       = tun_get_size,
2386         .fill_info      = tun_fill_info,
2387 };
2388
2389 static void tun_sock_write_space(struct sock *sk)
2390 {
2391         struct tun_file *tfile;
2392         wait_queue_head_t *wqueue;
2393
2394         if (!sock_writeable(sk))
2395                 return;
2396
2397         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2398                 return;
2399
2400         wqueue = sk_sleep(sk);
2401         if (wqueue && waitqueue_active(wqueue))
2402                 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2403                                                 EPOLLWRNORM | EPOLLWRBAND);
2404
2405         tfile = container_of(sk, struct tun_file, sk);
2406         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2407 }
2408
2409 static void tun_put_page(struct tun_page *tpage)
2410 {
2411         if (tpage->page)
2412                 __page_frag_cache_drain(tpage->page, tpage->count);
2413 }
2414
2415 static int tun_xdp_one(struct tun_struct *tun,
2416                        struct tun_file *tfile,
2417                        struct xdp_buff *xdp, int *flush,
2418                        struct tun_page *tpage)
2419 {
2420         unsigned int datasize = xdp->data_end - xdp->data;
2421         struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2422         struct virtio_net_hdr *gso = &hdr->gso;
2423         struct tun_pcpu_stats *stats;
2424         struct bpf_prog *xdp_prog;
2425         struct sk_buff *skb = NULL;
2426         u32 rxhash = 0, act;
2427         int buflen = hdr->buflen;
2428         int err = 0;
2429         bool skb_xdp = false;
2430         struct page *page;
2431
2432         xdp_prog = rcu_dereference(tun->xdp_prog);
2433         if (xdp_prog) {
2434                 if (gso->gso_type) {
2435                         skb_xdp = true;
2436                         goto build;
2437                 }
2438                 xdp_set_data_meta_invalid(xdp);
2439                 xdp->rxq = &tfile->xdp_rxq;
2440
2441                 act = bpf_prog_run_xdp(xdp_prog, xdp);
2442                 err = tun_xdp_act(tun, xdp_prog, xdp, act);
2443                 if (err < 0) {
2444                         put_page(virt_to_head_page(xdp->data));
2445                         return err;
2446                 }
2447
2448                 switch (err) {
2449                 case XDP_REDIRECT:
2450                         *flush = true;
2451                         /* fall through */
2452                 case XDP_TX:
2453                         return 0;
2454                 case XDP_PASS:
2455                         break;
2456                 default:
2457                         page = virt_to_head_page(xdp->data);
2458                         if (tpage->page == page) {
2459                                 ++tpage->count;
2460                         } else {
2461                                 tun_put_page(tpage);
2462                                 tpage->page = page;
2463                                 tpage->count = 1;
2464                         }
2465                         return 0;
2466                 }
2467         }
2468
2469 build:
2470         skb = build_skb(xdp->data_hard_start, buflen);
2471         if (!skb) {
2472                 err = -ENOMEM;
2473                 goto out;
2474         }
2475
2476         skb_reserve(skb, xdp->data - xdp->data_hard_start);
2477         skb_put(skb, xdp->data_end - xdp->data);
2478
2479         if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2480                 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
2481                 kfree_skb(skb);
2482                 err = -EINVAL;
2483                 goto out;
2484         }
2485
2486         skb->protocol = eth_type_trans(skb, tun->dev);
2487         skb_reset_network_header(skb);
2488         skb_probe_transport_header(skb);
2489
2490         if (skb_xdp) {
2491                 err = do_xdp_generic(xdp_prog, skb);
2492                 if (err != XDP_PASS)
2493                         goto out;
2494         }
2495
2496         if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2497             !tfile->detached)
2498                 rxhash = __skb_get_hash_symmetric(skb);
2499
2500         skb_record_rx_queue(skb, tfile->queue_index);
2501         netif_receive_skb(skb);
2502
2503         /* No need for get_cpu_ptr() here since this function is
2504          * always called with bh disabled
2505          */
2506         stats = this_cpu_ptr(tun->pcpu_stats);
2507         u64_stats_update_begin(&stats->syncp);
2508         stats->rx_packets++;
2509         stats->rx_bytes += datasize;
2510         u64_stats_update_end(&stats->syncp);
2511
2512         if (rxhash)
2513                 tun_flow_update(tun, rxhash, tfile);
2514
2515 out:
2516         return err;
2517 }
2518
2519 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2520 {
2521         int ret, i;
2522         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2523         struct tun_struct *tun = tun_get(tfile);
2524         struct tun_msg_ctl *ctl = m->msg_control;
2525         struct xdp_buff *xdp;
2526
2527         if (!tun)
2528                 return -EBADFD;
2529
2530         if (ctl && (ctl->type == TUN_MSG_PTR)) {
2531                 struct tun_page tpage;
2532                 int n = ctl->num;
2533                 int flush = 0;
2534
2535                 memset(&tpage, 0, sizeof(tpage));
2536
2537                 local_bh_disable();
2538                 rcu_read_lock();
2539
2540                 for (i = 0; i < n; i++) {
2541                         xdp = &((struct xdp_buff *)ctl->ptr)[i];
2542                         tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2543                 }
2544
2545                 if (flush)
2546                         xdp_do_flush_map();
2547
2548                 rcu_read_unlock();
2549                 local_bh_enable();
2550
2551                 tun_put_page(&tpage);
2552
2553                 ret = total_len;
2554                 goto out;
2555         }
2556
2557         ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2558                            m->msg_flags & MSG_DONTWAIT,
2559                            m->msg_flags & MSG_MORE);
2560 out:
2561         tun_put(tun);
2562         return ret;
2563 }
2564
2565 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2566                        int flags)
2567 {
2568         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2569         struct tun_struct *tun = tun_get(tfile);
2570         void *ptr = m->msg_control;
2571         int ret;
2572
2573         if (!tun) {
2574                 ret = -EBADFD;
2575                 goto out_free;
2576         }
2577
2578         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2579                 ret = -EINVAL;
2580                 goto out_put_tun;
2581         }
2582         if (flags & MSG_ERRQUEUE) {
2583                 ret = sock_recv_errqueue(sock->sk, m, total_len,
2584                                          SOL_PACKET, TUN_TX_TIMESTAMP);
2585                 goto out;
2586         }
2587         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2588         if (ret > (ssize_t)total_len) {
2589                 m->msg_flags |= MSG_TRUNC;
2590                 ret = flags & MSG_TRUNC ? ret : total_len;
2591         }
2592 out:
2593         tun_put(tun);
2594         return ret;
2595
2596 out_put_tun:
2597         tun_put(tun);
2598 out_free:
2599         tun_ptr_free(ptr);
2600         return ret;
2601 }
2602
2603 static int tun_ptr_peek_len(void *ptr)
2604 {
2605         if (likely(ptr)) {
2606                 if (tun_is_xdp_frame(ptr)) {
2607                         struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2608
2609                         return xdpf->len;
2610                 }
2611                 return __skb_array_len_with_tag(ptr);
2612         } else {
2613                 return 0;
2614         }
2615 }
2616
2617 static int tun_peek_len(struct socket *sock)
2618 {
2619         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2620         struct tun_struct *tun;
2621         int ret = 0;
2622
2623         tun = tun_get(tfile);
2624         if (!tun)
2625                 return 0;
2626
2627         ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2628         tun_put(tun);
2629
2630         return ret;
2631 }
2632
2633 /* Ops structure to mimic raw sockets with tun */
2634 static const struct proto_ops tun_socket_ops = {
2635         .peek_len = tun_peek_len,
2636         .sendmsg = tun_sendmsg,
2637         .recvmsg = tun_recvmsg,
2638 };
2639
2640 static struct proto tun_proto = {
2641         .name           = "tun",
2642         .owner          = THIS_MODULE,
2643         .obj_size       = sizeof(struct tun_file),
2644 };
2645
2646 static int tun_flags(struct tun_struct *tun)
2647 {
2648         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2649 }
2650
2651 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2652                               char *buf)
2653 {
2654         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2655         return sprintf(buf, "0x%x\n", tun_flags(tun));
2656 }
2657
2658 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2659                               char *buf)
2660 {
2661         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2662         return uid_valid(tun->owner)?
2663                 sprintf(buf, "%u\n",
2664                         from_kuid_munged(current_user_ns(), tun->owner)):
2665                 sprintf(buf, "-1\n");
2666 }
2667
2668 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2669                               char *buf)
2670 {
2671         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2672         return gid_valid(tun->group) ?
2673                 sprintf(buf, "%u\n",
2674                         from_kgid_munged(current_user_ns(), tun->group)):
2675                 sprintf(buf, "-1\n");
2676 }
2677
2678 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2679 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2680 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2681
2682 static struct attribute *tun_dev_attrs[] = {
2683         &dev_attr_tun_flags.attr,
2684         &dev_attr_owner.attr,
2685         &dev_attr_group.attr,
2686         NULL
2687 };
2688
2689 static const struct attribute_group tun_attr_group = {
2690         .attrs = tun_dev_attrs
2691 };
2692
2693 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2694 {
2695         struct tun_struct *tun;
2696         struct tun_file *tfile = file->private_data;
2697         struct net_device *dev;
2698         int err;
2699
2700         if (tfile->detached)
2701                 return -EINVAL;
2702
2703         if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2704                 if (!capable(CAP_NET_ADMIN))
2705                         return -EPERM;
2706
2707                 if (!(ifr->ifr_flags & IFF_NAPI) ||
2708                     (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2709                         return -EINVAL;
2710         }
2711
2712         dev = __dev_get_by_name(net, ifr->ifr_name);
2713         if (dev) {
2714                 if (ifr->ifr_flags & IFF_TUN_EXCL)
2715                         return -EBUSY;
2716                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2717                         tun = netdev_priv(dev);
2718                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2719                         tun = netdev_priv(dev);
2720                 else
2721                         return -EINVAL;
2722
2723                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2724                     !!(tun->flags & IFF_MULTI_QUEUE))
2725                         return -EINVAL;
2726
2727                 if (tun_not_capable(tun))
2728                         return -EPERM;
2729                 err = security_tun_dev_open(tun->security);
2730                 if (err < 0)
2731                         return err;
2732
2733                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2734                                  ifr->ifr_flags & IFF_NAPI,
2735                                  ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2736                 if (err < 0)
2737                         return err;
2738
2739                 if (tun->flags & IFF_MULTI_QUEUE &&
2740                     (tun->numqueues + tun->numdisabled > 1)) {
2741                         /* One or more queue has already been attached, no need
2742                          * to initialize the device again.
2743                          */
2744                         netdev_state_change(dev);
2745                         return 0;
2746                 }
2747
2748                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2749                               (ifr->ifr_flags & TUN_FEATURES);
2750
2751                 netdev_state_change(dev);
2752         } else {
2753                 char *name;
2754                 unsigned long flags = 0;
2755                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2756                              MAX_TAP_QUEUES : 1;
2757
2758                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2759                         return -EPERM;
2760                 err = security_tun_dev_create();
2761                 if (err < 0)
2762                         return err;
2763
2764                 /* Set dev type */
2765                 if (ifr->ifr_flags & IFF_TUN) {
2766                         /* TUN device */
2767                         flags |= IFF_TUN;
2768                         name = "tun%d";
2769                 } else if (ifr->ifr_flags & IFF_TAP) {
2770                         /* TAP device */
2771                         flags |= IFF_TAP;
2772                         name = "tap%d";
2773                 } else
2774                         return -EINVAL;
2775
2776                 if (*ifr->ifr_name)
2777                         name = ifr->ifr_name;
2778
2779                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2780                                        NET_NAME_UNKNOWN, tun_setup, queues,
2781                                        queues);
2782
2783                 if (!dev)
2784                         return -ENOMEM;
2785                 err = dev_get_valid_name(net, dev, name);
2786                 if (err < 0)
2787                         goto err_free_dev;
2788
2789                 dev_net_set(dev, net);
2790                 dev->rtnl_link_ops = &tun_link_ops;
2791                 dev->ifindex = tfile->ifindex;
2792                 dev->sysfs_groups[0] = &tun_attr_group;
2793
2794                 tun = netdev_priv(dev);
2795                 tun->dev = dev;
2796                 tun->flags = flags;
2797                 tun->txflt.count = 0;
2798                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2799
2800                 tun->align = NET_SKB_PAD;
2801                 tun->filter_attached = false;
2802                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2803                 tun->rx_batched = 0;
2804                 RCU_INIT_POINTER(tun->steering_prog, NULL);
2805
2806                 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2807                 if (!tun->pcpu_stats) {
2808                         err = -ENOMEM;
2809                         goto err_free_dev;
2810                 }
2811
2812                 spin_lock_init(&tun->lock);
2813
2814                 err = security_tun_dev_alloc_security(&tun->security);
2815                 if (err < 0)
2816                         goto err_free_stat;
2817
2818                 tun_net_init(dev);
2819                 tun_flow_init(tun);
2820
2821                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2822                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2823                                    NETIF_F_HW_VLAN_STAG_TX;
2824                 dev->features = dev->hw_features | NETIF_F_LLTX;
2825                 dev->vlan_features = dev->features &
2826                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
2827                                        NETIF_F_HW_VLAN_STAG_TX);
2828
2829                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2830                               (ifr->ifr_flags & TUN_FEATURES);
2831
2832                 INIT_LIST_HEAD(&tun->disabled);
2833                 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI,
2834                                  ifr->ifr_flags & IFF_NAPI_FRAGS, false);
2835                 if (err < 0)
2836                         goto err_free_flow;
2837
2838                 err = register_netdevice(tun->dev);
2839                 if (err < 0)
2840                         goto err_detach;
2841                 /* free_netdev() won't check refcnt, to aovid race
2842                  * with dev_put() we need publish tun after registration.
2843                  */
2844                 rcu_assign_pointer(tfile->tun, tun);
2845         }
2846
2847         netif_carrier_on(tun->dev);
2848
2849         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2850
2851         /* Make sure persistent devices do not get stuck in
2852          * xoff state.
2853          */
2854         if (netif_running(tun->dev))
2855                 netif_tx_wake_all_queues(tun->dev);
2856
2857         strcpy(ifr->ifr_name, tun->dev->name);
2858         return 0;
2859
2860 err_detach:
2861         tun_detach_all(dev);
2862         /* register_netdevice() already called tun_free_netdev() */
2863         goto err_free_dev;
2864
2865 err_free_flow:
2866         tun_flow_uninit(tun);
2867         security_tun_dev_free_security(tun->security);
2868 err_free_stat:
2869         free_percpu(tun->pcpu_stats);
2870 err_free_dev:
2871         free_netdev(dev);
2872         return err;
2873 }
2874
2875 static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2876 {
2877         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2878
2879         strcpy(ifr->ifr_name, tun->dev->name);
2880
2881         ifr->ifr_flags = tun_flags(tun);
2882
2883 }
2884
2885 /* This is like a cut-down ethtool ops, except done via tun fd so no
2886  * privs required. */
2887 static int set_offload(struct tun_struct *tun, unsigned long arg)
2888 {
2889         netdev_features_t features = 0;
2890
2891         if (arg & TUN_F_CSUM) {
2892                 features |= NETIF_F_HW_CSUM;
2893                 arg &= ~TUN_F_CSUM;
2894
2895                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2896                         if (arg & TUN_F_TSO_ECN) {
2897                                 features |= NETIF_F_TSO_ECN;
2898                                 arg &= ~TUN_F_TSO_ECN;
2899                         }
2900                         if (arg & TUN_F_TSO4)
2901                                 features |= NETIF_F_TSO;
2902                         if (arg & TUN_F_TSO6)
2903                                 features |= NETIF_F_TSO6;
2904                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2905                 }
2906
2907                 arg &= ~TUN_F_UFO;
2908         }
2909
2910         /* This gives the user a way to test for new features in future by
2911          * trying to set them. */
2912         if (arg)
2913                 return -EINVAL;
2914
2915         tun->set_features = features;
2916         tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2917         tun->dev->wanted_features |= features;
2918         netdev_update_features(tun->dev);
2919
2920         return 0;
2921 }
2922
2923 static void tun_detach_filter(struct tun_struct *tun, int n)
2924 {
2925         int i;
2926         struct tun_file *tfile;
2927
2928         for (i = 0; i < n; i++) {
2929                 tfile = rtnl_dereference(tun->tfiles[i]);
2930                 lock_sock(tfile->socket.sk);
2931                 sk_detach_filter(tfile->socket.sk);
2932                 release_sock(tfile->socket.sk);
2933         }
2934
2935         tun->filter_attached = false;
2936 }
2937
2938 static int tun_attach_filter(struct tun_struct *tun)
2939 {
2940         int i, ret = 0;
2941         struct tun_file *tfile;
2942
2943         for (i = 0; i < tun->numqueues; i++) {
2944                 tfile = rtnl_dereference(tun->tfiles[i]);
2945                 lock_sock(tfile->socket.sk);
2946                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2947                 release_sock(tfile->socket.sk);
2948                 if (ret) {
2949                         tun_detach_filter(tun, i);
2950                         return ret;
2951                 }
2952         }
2953
2954         tun->filter_attached = true;
2955         return ret;
2956 }
2957
2958 static void tun_set_sndbuf(struct tun_struct *tun)
2959 {
2960         struct tun_file *tfile;
2961         int i;
2962
2963         for (i = 0; i < tun->numqueues; i++) {
2964                 tfile = rtnl_dereference(tun->tfiles[i]);
2965                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2966         }
2967 }
2968
2969 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2970 {
2971         struct tun_file *tfile = file->private_data;
2972         struct tun_struct *tun;
2973         int ret = 0;
2974
2975         rtnl_lock();
2976
2977         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2978                 tun = tfile->detached;
2979                 if (!tun) {
2980                         ret = -EINVAL;
2981                         goto unlock;
2982                 }
2983                 ret = security_tun_dev_attach_queue(tun->security);
2984                 if (ret < 0)
2985                         goto unlock;
2986                 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2987                                  tun->flags & IFF_NAPI_FRAGS, true);
2988         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2989                 tun = rtnl_dereference(tfile->tun);
2990                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2991                         ret = -EINVAL;
2992                 else
2993                         __tun_detach(tfile, false);
2994         } else
2995                 ret = -EINVAL;
2996
2997         if (ret >= 0)
2998                 netdev_state_change(tun->dev);
2999
3000 unlock:
3001         rtnl_unlock();
3002         return ret;
3003 }
3004
3005 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
3006                         void __user *data)
3007 {
3008         struct bpf_prog *prog;
3009         int fd;
3010
3011         if (copy_from_user(&fd, data, sizeof(fd)))
3012                 return -EFAULT;
3013
3014         if (fd == -1) {
3015                 prog = NULL;
3016         } else {
3017                 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
3018                 if (IS_ERR(prog))
3019                         return PTR_ERR(prog);
3020         }
3021
3022         return __tun_set_ebpf(tun, prog_p, prog);
3023 }
3024
3025 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
3026                             unsigned long arg, int ifreq_len)
3027 {
3028         struct tun_file *tfile = file->private_data;
3029         struct net *net = sock_net(&tfile->sk);
3030         struct tun_struct *tun;
3031         void __user* argp = (void __user*)arg;
3032         unsigned int ifindex, carrier;
3033         struct ifreq ifr;
3034         kuid_t owner;
3035         kgid_t group;
3036         int sndbuf;
3037         int vnet_hdr_sz;
3038         int le;
3039         int ret;
3040         bool do_notify = false;
3041
3042         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3043             (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3044                 if (copy_from_user(&ifr, argp, ifreq_len))
3045                         return -EFAULT;
3046         } else {
3047                 memset(&ifr, 0, sizeof(ifr));
3048         }
3049         if (cmd == TUNGETFEATURES) {
3050                 /* Currently this just means: "what IFF flags are valid?".
3051                  * This is needed because we never checked for invalid flags on
3052                  * TUNSETIFF.
3053                  */
3054                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
3055                                 (unsigned int __user*)argp);
3056         } else if (cmd == TUNSETQUEUE) {
3057                 return tun_set_queue(file, &ifr);
3058         } else if (cmd == SIOCGSKNS) {
3059                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3060                         return -EPERM;
3061                 return open_related_ns(&net->ns, get_net_ns);
3062         }
3063
3064         ret = 0;
3065         rtnl_lock();
3066
3067         tun = tun_get(tfile);
3068         if (cmd == TUNSETIFF) {
3069                 ret = -EEXIST;
3070                 if (tun)
3071                         goto unlock;
3072
3073                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3074
3075                 ret = tun_set_iff(net, file, &ifr);
3076
3077                 if (ret)
3078                         goto unlock;
3079
3080                 if (copy_to_user(argp, &ifr, ifreq_len))
3081                         ret = -EFAULT;
3082                 goto unlock;
3083         }
3084         if (cmd == TUNSETIFINDEX) {
3085                 ret = -EPERM;
3086                 if (tun)
3087                         goto unlock;
3088
3089                 ret = -EFAULT;
3090                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3091                         goto unlock;
3092
3093                 ret = 0;
3094                 tfile->ifindex = ifindex;
3095                 goto unlock;
3096         }
3097
3098         ret = -EBADFD;
3099         if (!tun)
3100                 goto unlock;
3101
3102         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
3103
3104         net = dev_net(tun->dev);
3105         ret = 0;
3106         switch (cmd) {
3107         case TUNGETIFF:
3108                 tun_get_iff(tun, &ifr);
3109
3110                 if (tfile->detached)
3111                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
3112                 if (!tfile->socket.sk->sk_filter)
3113                         ifr.ifr_flags |= IFF_NOFILTER;
3114
3115                 if (copy_to_user(argp, &ifr, ifreq_len))
3116                         ret = -EFAULT;
3117                 break;
3118
3119         case TUNSETNOCSUM:
3120                 /* Disable/Enable checksum */
3121
3122                 /* [unimplemented] */
3123                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
3124                           arg ? "disabled" : "enabled");
3125                 break;
3126
3127         case TUNSETPERSIST:
3128                 /* Disable/Enable persist mode. Keep an extra reference to the
3129                  * module to prevent the module being unprobed.
3130                  */
3131                 if (arg && !(tun->flags & IFF_PERSIST)) {
3132                         tun->flags |= IFF_PERSIST;
3133                         __module_get(THIS_MODULE);
3134                         do_notify = true;
3135                 }
3136                 if (!arg && (tun->flags & IFF_PERSIST)) {
3137                         tun->flags &= ~IFF_PERSIST;
3138                         module_put(THIS_MODULE);
3139                         do_notify = true;
3140                 }
3141
3142                 tun_debug(KERN_INFO, tun, "persist %s\n",
3143                           arg ? "enabled" : "disabled");
3144                 break;
3145
3146         case TUNSETOWNER:
3147                 /* Set owner of the device */
3148                 owner = make_kuid(current_user_ns(), arg);
3149                 if (!uid_valid(owner)) {
3150                         ret = -EINVAL;
3151                         break;
3152                 }
3153                 tun->owner = owner;
3154                 do_notify = true;
3155                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
3156                           from_kuid(&init_user_ns, tun->owner));
3157                 break;
3158
3159         case TUNSETGROUP:
3160                 /* Set group of the device */
3161                 group = make_kgid(current_user_ns(), arg);
3162                 if (!gid_valid(group)) {
3163                         ret = -EINVAL;
3164                         break;
3165                 }
3166                 tun->group = group;
3167                 do_notify = true;
3168                 tun_debug(KERN_INFO, tun, "group set to %u\n",
3169                           from_kgid(&init_user_ns, tun->group));
3170                 break;
3171
3172         case TUNSETLINK:
3173                 /* Only allow setting the type when the interface is down */
3174                 if (tun->dev->flags & IFF_UP) {
3175                         tun_debug(KERN_INFO, tun,
3176                                   "Linktype set failed because interface is up\n");
3177                         ret = -EBUSY;
3178                 } else {
3179                         tun->dev->type = (int) arg;
3180                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
3181                                   tun->dev->type);
3182                         ret = 0;
3183                 }
3184                 break;
3185
3186 #ifdef TUN_DEBUG
3187         case TUNSETDEBUG:
3188                 tun->debug = arg;
3189                 break;
3190 #endif
3191         case TUNSETOFFLOAD:
3192                 ret = set_offload(tun, arg);
3193                 break;
3194
3195         case TUNSETTXFILTER:
3196                 /* Can be set only for TAPs */
3197                 ret = -EINVAL;
3198                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3199                         break;
3200                 ret = update_filter(&tun->txflt, (void __user *)arg);
3201                 break;
3202
3203         case SIOCGIFHWADDR:
3204                 /* Get hw address */
3205                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3206                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3207                 if (copy_to_user(argp, &ifr, ifreq_len))
3208                         ret = -EFAULT;
3209                 break;
3210
3211         case SIOCSIFHWADDR:
3212                 /* Set hw address */
3213                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
3214                           ifr.ifr_hwaddr.sa_data);
3215
3216                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr, NULL);
3217                 break;
3218
3219         case TUNGETSNDBUF:
3220                 sndbuf = tfile->socket.sk->sk_sndbuf;
3221                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3222                         ret = -EFAULT;
3223                 break;
3224
3225         case TUNSETSNDBUF:
3226                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3227                         ret = -EFAULT;
3228                         break;
3229                 }
3230                 if (sndbuf <= 0) {
3231                         ret = -EINVAL;
3232                         break;
3233                 }
3234
3235                 tun->sndbuf = sndbuf;
3236                 tun_set_sndbuf(tun);
3237                 break;
3238
3239         case TUNGETVNETHDRSZ:
3240                 vnet_hdr_sz = tun->vnet_hdr_sz;
3241                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3242                         ret = -EFAULT;
3243                 break;
3244
3245         case TUNSETVNETHDRSZ:
3246                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3247                         ret = -EFAULT;
3248                         break;
3249                 }
3250                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3251                         ret = -EINVAL;
3252                         break;
3253                 }
3254
3255                 tun->vnet_hdr_sz = vnet_hdr_sz;
3256                 break;
3257
3258         case TUNGETVNETLE:
3259                 le = !!(tun->flags & TUN_VNET_LE);
3260                 if (put_user(le, (int __user *)argp))
3261                         ret = -EFAULT;
3262                 break;
3263
3264         case TUNSETVNETLE:
3265                 if (get_user(le, (int __user *)argp)) {
3266                         ret = -EFAULT;
3267                         break;
3268                 }
3269                 if (le)
3270                         tun->flags |= TUN_VNET_LE;
3271                 else
3272                         tun->flags &= ~TUN_VNET_LE;
3273                 break;
3274
3275         case TUNGETVNETBE:
3276                 ret = tun_get_vnet_be(tun, argp);
3277                 break;
3278
3279         case TUNSETVNETBE:
3280                 ret = tun_set_vnet_be(tun, argp);
3281                 break;
3282
3283         case TUNATTACHFILTER:
3284                 /* Can be set only for TAPs */
3285                 ret = -EINVAL;
3286                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3287                         break;
3288                 ret = -EFAULT;
3289                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3290                         break;
3291
3292                 ret = tun_attach_filter(tun);
3293                 break;
3294
3295         case TUNDETACHFILTER:
3296                 /* Can be set only for TAPs */
3297                 ret = -EINVAL;
3298                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3299                         break;
3300                 ret = 0;
3301                 tun_detach_filter(tun, tun->numqueues);
3302                 break;
3303
3304         case TUNGETFILTER:
3305                 ret = -EINVAL;
3306                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3307                         break;
3308                 ret = -EFAULT;
3309                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3310                         break;
3311                 ret = 0;
3312                 break;
3313
3314         case TUNSETSTEERINGEBPF:
3315                 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3316                 break;
3317
3318         case TUNSETFILTEREBPF:
3319                 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3320                 break;
3321
3322         case TUNSETCARRIER:
3323                 ret = -EFAULT;
3324                 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3325                         goto unlock;
3326
3327                 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3328                 break;
3329
3330         case TUNGETDEVNETNS:
3331                 ret = -EPERM;
3332                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3333                         goto unlock;
3334                 ret = open_related_ns(&net->ns, get_net_ns);
3335                 break;
3336
3337         default:
3338                 ret = -EINVAL;
3339                 break;
3340         }
3341
3342         if (do_notify)
3343                 netdev_state_change(tun->dev);
3344
3345 unlock:
3346         rtnl_unlock();
3347         if (tun)
3348                 tun_put(tun);
3349         return ret;
3350 }
3351
3352 static long tun_chr_ioctl(struct file *file,
3353                           unsigned int cmd, unsigned long arg)
3354 {
3355         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3356 }
3357
3358 #ifdef CONFIG_COMPAT
3359 static long tun_chr_compat_ioctl(struct file *file,
3360                          unsigned int cmd, unsigned long arg)
3361 {
3362         switch (cmd) {
3363         case TUNSETIFF:
3364         case TUNGETIFF:
3365         case TUNSETTXFILTER:
3366         case TUNGETSNDBUF:
3367         case TUNSETSNDBUF:
3368         case SIOCGIFHWADDR:
3369         case SIOCSIFHWADDR:
3370                 arg = (unsigned long)compat_ptr(arg);
3371                 break;
3372         default:
3373                 arg = (compat_ulong_t)arg;
3374                 break;
3375         }
3376
3377         /*
3378          * compat_ifreq is shorter than ifreq, so we must not access beyond
3379          * the end of that structure. All fields that are used in this
3380          * driver are compatible though, we don't need to convert the
3381          * contents.
3382          */
3383         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3384 }
3385 #endif /* CONFIG_COMPAT */
3386
3387 static int tun_chr_fasync(int fd, struct file *file, int on)
3388 {
3389         struct tun_file *tfile = file->private_data;
3390         int ret;
3391
3392         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3393                 goto out;
3394
3395         if (on) {
3396                 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3397                 tfile->flags |= TUN_FASYNC;
3398         } else
3399                 tfile->flags &= ~TUN_FASYNC;
3400         ret = 0;
3401 out:
3402         return ret;
3403 }
3404
3405 static int tun_chr_open(struct inode *inode, struct file * file)
3406 {
3407         struct net *net = current->nsproxy->net_ns;
3408         struct tun_file *tfile;
3409
3410         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
3411
3412         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3413                                             &tun_proto, 0);
3414         if (!tfile)
3415                 return -ENOMEM;
3416         if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3417                 sk_free(&tfile->sk);
3418                 return -ENOMEM;
3419         }
3420
3421         mutex_init(&tfile->napi_mutex);
3422         RCU_INIT_POINTER(tfile->tun, NULL);
3423         tfile->flags = 0;
3424         tfile->ifindex = 0;
3425
3426         init_waitqueue_head(&tfile->socket.wq.wait);
3427
3428         tfile->socket.file = file;
3429         tfile->socket.ops = &tun_socket_ops;
3430
3431         sock_init_data(&tfile->socket, &tfile->sk);
3432
3433         tfile->sk.sk_write_space = tun_sock_write_space;
3434         tfile->sk.sk_sndbuf = INT_MAX;
3435
3436         file->private_data = tfile;
3437         INIT_LIST_HEAD(&tfile->next);
3438
3439         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3440
3441         return 0;
3442 }
3443
3444 static int tun_chr_close(struct inode *inode, struct file *file)
3445 {
3446         struct tun_file *tfile = file->private_data;
3447
3448         tun_detach(tfile, true);
3449
3450         return 0;
3451 }
3452
3453 #ifdef CONFIG_PROC_FS
3454 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3455 {
3456         struct tun_file *tfile = file->private_data;
3457         struct tun_struct *tun;
3458         struct ifreq ifr;
3459
3460         memset(&ifr, 0, sizeof(ifr));
3461
3462         rtnl_lock();
3463         tun = tun_get(tfile);
3464         if (tun)
3465                 tun_get_iff(tun, &ifr);
3466         rtnl_unlock();
3467
3468         if (tun)
3469                 tun_put(tun);
3470
3471         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3472 }
3473 #endif
3474
3475 static const struct file_operations tun_fops = {
3476         .owner  = THIS_MODULE,
3477         .llseek = no_llseek,
3478         .read_iter  = tun_chr_read_iter,
3479         .write_iter = tun_chr_write_iter,
3480         .poll   = tun_chr_poll,
3481         .unlocked_ioctl = tun_chr_ioctl,
3482 #ifdef CONFIG_COMPAT
3483         .compat_ioctl = tun_chr_compat_ioctl,
3484 #endif
3485         .open   = tun_chr_open,
3486         .release = tun_chr_close,
3487         .fasync = tun_chr_fasync,
3488 #ifdef CONFIG_PROC_FS
3489         .show_fdinfo = tun_chr_show_fdinfo,
3490 #endif
3491 };
3492
3493 static struct miscdevice tun_miscdev = {
3494         .minor = TUN_MINOR,
3495         .name = "tun",
3496         .nodename = "net/tun",
3497         .fops = &tun_fops,
3498 };
3499
3500 /* ethtool interface */
3501
3502 static void tun_default_link_ksettings(struct net_device *dev,
3503                                        struct ethtool_link_ksettings *cmd)
3504 {
3505         ethtool_link_ksettings_zero_link_mode(cmd, supported);
3506         ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3507         cmd->base.speed         = SPEED_10;
3508         cmd->base.duplex        = DUPLEX_FULL;
3509         cmd->base.port          = PORT_TP;
3510         cmd->base.phy_address   = 0;
3511         cmd->base.autoneg       = AUTONEG_DISABLE;
3512 }
3513
3514 static int tun_get_link_ksettings(struct net_device *dev,
3515                                   struct ethtool_link_ksettings *cmd)
3516 {
3517         struct tun_struct *tun = netdev_priv(dev);
3518
3519         memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3520         return 0;
3521 }
3522
3523 static int tun_set_link_ksettings(struct net_device *dev,
3524                                   const struct ethtool_link_ksettings *cmd)
3525 {
3526         struct tun_struct *tun = netdev_priv(dev);
3527
3528         memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3529         return 0;
3530 }
3531
3532 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3533 {
3534         struct tun_struct *tun = netdev_priv(dev);
3535
3536         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3537         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3538
3539         switch (tun->flags & TUN_TYPE_MASK) {
3540         case IFF_TUN:
3541                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3542                 break;
3543         case IFF_TAP:
3544                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3545                 break;
3546         }
3547 }
3548
3549 static u32 tun_get_msglevel(struct net_device *dev)
3550 {
3551 #ifdef TUN_DEBUG
3552         struct tun_struct *tun = netdev_priv(dev);
3553         return tun->debug;
3554 #else
3555         return -EOPNOTSUPP;
3556 #endif
3557 }
3558
3559 static void tun_set_msglevel(struct net_device *dev, u32 value)
3560 {
3561 #ifdef TUN_DEBUG
3562         struct tun_struct *tun = netdev_priv(dev);
3563         tun->debug = value;
3564 #endif
3565 }
3566
3567 static int tun_get_coalesce(struct net_device *dev,
3568                             struct ethtool_coalesce *ec)
3569 {
3570         struct tun_struct *tun = netdev_priv(dev);
3571
3572         ec->rx_max_coalesced_frames = tun->rx_batched;
3573
3574         return 0;
3575 }
3576
3577 static int tun_set_coalesce(struct net_device *dev,
3578                             struct ethtool_coalesce *ec)
3579 {
3580         struct tun_struct *tun = netdev_priv(dev);
3581
3582         if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3583                 tun->rx_batched = NAPI_POLL_WEIGHT;
3584         else
3585                 tun->rx_batched = ec->rx_max_coalesced_frames;
3586
3587         return 0;
3588 }
3589
3590 static const struct ethtool_ops tun_ethtool_ops = {
3591         .get_drvinfo    = tun_get_drvinfo,
3592         .get_msglevel   = tun_get_msglevel,
3593         .set_msglevel   = tun_set_msglevel,
3594         .get_link       = ethtool_op_get_link,
3595         .get_ts_info    = ethtool_op_get_ts_info,
3596         .get_coalesce   = tun_get_coalesce,
3597         .set_coalesce   = tun_set_coalesce,
3598         .get_link_ksettings = tun_get_link_ksettings,
3599         .set_link_ksettings = tun_set_link_ksettings,
3600 };
3601
3602 static int tun_queue_resize(struct tun_struct *tun)
3603 {
3604         struct net_device *dev = tun->dev;
3605         struct tun_file *tfile;
3606         struct ptr_ring **rings;
3607         int n = tun->numqueues + tun->numdisabled;
3608         int ret, i;
3609
3610         rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3611         if (!rings)
3612                 return -ENOMEM;
3613
3614         for (i = 0; i < tun->numqueues; i++) {
3615                 tfile = rtnl_dereference(tun->tfiles[i]);
3616                 rings[i] = &tfile->tx_ring;
3617         }
3618         list_for_each_entry(tfile, &tun->disabled, next)
3619                 rings[i++] = &tfile->tx_ring;
3620
3621         ret = ptr_ring_resize_multiple(rings, n,
3622                                        dev->tx_queue_len, GFP_KERNEL,
3623                                        tun_ptr_free);
3624
3625         kfree(rings);
3626         return ret;
3627 }
3628
3629 static int tun_device_event(struct notifier_block *unused,
3630                             unsigned long event, void *ptr)
3631 {
3632         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3633         struct tun_struct *tun = netdev_priv(dev);
3634         int i;
3635
3636         if (dev->rtnl_link_ops != &tun_link_ops)
3637                 return NOTIFY_DONE;
3638
3639         switch (event) {
3640         case NETDEV_CHANGE_TX_QUEUE_LEN:
3641                 if (tun_queue_resize(tun))
3642                         return NOTIFY_BAD;
3643                 break;
3644         case NETDEV_UP:
3645                 for (i = 0; i < tun->numqueues; i++) {
3646                         struct tun_file *tfile;
3647
3648                         tfile = rtnl_dereference(tun->tfiles[i]);
3649                         tfile->socket.sk->sk_write_space(tfile->socket.sk);
3650                 }
3651                 break;
3652         default:
3653                 break;
3654         }
3655
3656         return NOTIFY_DONE;
3657 }
3658
3659 static struct notifier_block tun_notifier_block __read_mostly = {
3660         .notifier_call  = tun_device_event,
3661 };
3662
3663 static int __init tun_init(void)
3664 {
3665         int ret = 0;
3666
3667         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3668
3669         ret = rtnl_link_register(&tun_link_ops);
3670         if (ret) {
3671                 pr_err("Can't register link_ops\n");
3672                 goto err_linkops;
3673         }
3674
3675         ret = misc_register(&tun_miscdev);
3676         if (ret) {
3677                 pr_err("Can't register misc device %d\n", TUN_MINOR);
3678                 goto err_misc;
3679         }
3680
3681         ret = register_netdevice_notifier(&tun_notifier_block);
3682         if (ret) {
3683                 pr_err("Can't register netdevice notifier\n");
3684                 goto err_notifier;
3685         }
3686
3687         return  0;
3688
3689 err_notifier:
3690         misc_deregister(&tun_miscdev);
3691 err_misc:
3692         rtnl_link_unregister(&tun_link_ops);
3693 err_linkops:
3694         return ret;
3695 }
3696
3697 static void tun_cleanup(void)
3698 {
3699         misc_deregister(&tun_miscdev);
3700         rtnl_link_unregister(&tun_link_ops);
3701         unregister_netdevice_notifier(&tun_notifier_block);
3702 }
3703
3704 /* Get an underlying socket object from tun file.  Returns error unless file is
3705  * attached to a device.  The returned object works like a packet socket, it
3706  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
3707  * holding a reference to the file for as long as the socket is in use. */
3708 struct socket *tun_get_socket(struct file *file)
3709 {
3710         struct tun_file *tfile;
3711         if (file->f_op != &tun_fops)
3712                 return ERR_PTR(-EINVAL);
3713         tfile = file->private_data;
3714         if (!tfile)
3715                 return ERR_PTR(-EBADFD);
3716         return &tfile->socket;
3717 }
3718 EXPORT_SYMBOL_GPL(tun_get_socket);
3719
3720 struct ptr_ring *tun_get_tx_ring(struct file *file)
3721 {
3722         struct tun_file *tfile;
3723
3724         if (file->f_op != &tun_fops)
3725                 return ERR_PTR(-EINVAL);
3726         tfile = file->private_data;
3727         if (!tfile)
3728                 return ERR_PTR(-EBADFD);
3729         return &tfile->tx_ring;
3730 }
3731 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3732
3733 module_init(tun_init);
3734 module_exit(tun_cleanup);
3735 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3736 MODULE_AUTHOR(DRV_COPYRIGHT);
3737 MODULE_LICENSE("GPL");
3738 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3739 MODULE_ALIAS("devname:net/tun");