drivers/net/tun.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  TUN - Universal TUN/TAP device driver.
   4  *  Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
   5  *
   6  *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
   7  */
   8
   9 /*
  10  *  Changes:
  11  *
  12  *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
  13  *    Add TUNSETLINK ioctl to set the link encapsulation
  14  *
  15  *  Mark Smith <markzzzsmith@yahoo.com.au>
  16  *    Use eth_random_addr() for tap MAC address.
  17  *
  18  *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
  19  *    Fixes in packet dropping, queue length setting and queue wakeup.
  20  *    Increased default tx queue length.
  21  *    Added ethtool API.
  22  *    Minor cleanups
  23  *
  24  *  Daniel Podlejski <underley@underley.eu.org>
  25  *    Modifications for 2.3.99-pre5 kernel.
  26  */
  27
  28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  29
  30 #define DRV_NAME        "tun"
  31 #define DRV_VERSION     "1.6"
  32 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  33 #define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
  34
  35 #include <linux/module.h>
  36 #include <linux/errno.h>
  37 #include <linux/kernel.h>
  38 #include <linux/sched/signal.h>
  39 #include <linux/major.h>
  40 #include <linux/slab.h>
  41 #include <linux/poll.h>
  42 #include <linux/fcntl.h>
  43 #include <linux/init.h>
  44 #include <linux/skbuff.h>
  45 #include <linux/netdevice.h>
  46 #include <linux/etherdevice.h>
  47 #include <linux/miscdevice.h>
  48 #include <linux/ethtool.h>
  49 #include <linux/rtnetlink.h>
  50 #include <linux/compat.h>
  51 #include <linux/if.h>
  52 #include <linux/if_arp.h>
  53 #include <linux/if_ether.h>
  54 #include <linux/if_tun.h>
  55 #include <linux/if_vlan.h>
  56 #include <linux/crc32.h>
  57 #include <linux/nsproxy.h>
  58 #include <linux/virtio_net.h>
  59 #include <linux/rcupdate.h>
  60 #include <net/net_namespace.h>
  61 #include <net/netns/generic.h>
  62 #include <net/rtnetlink.h>
  63 #include <net/sock.h>
  64 #include <net/xdp.h>
  65 #include <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_tx_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                         if (act == XDP_REDIRECT || act == XDP_TX)
1720                                 put_page(alloc_frag->page);
1721                         goto out;
1722                 }
1723
1724                 if (err == XDP_REDIRECT)
1725                         xdp_do_flush_map();
1726                 if (err != XDP_PASS)
1727                         goto out;
1728
1729                 pad = xdp.data - xdp.data_hard_start;
1730                 len = xdp.data_end - xdp.data;
1731         }
1732         rcu_read_unlock();
1733         local_bh_enable();
1734
1735         return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1736
1737 out:
1738         rcu_read_unlock();
1739         local_bh_enable();
1740         return NULL;
1741 }
1742
1743 /* Get packet from user space buffer */
1744 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1745                             void *msg_control, struct iov_iter *from,
1746                             int noblock, bool more)
1747 {
1748         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1749         struct sk_buff *skb;
1750         size_t total_len = iov_iter_count(from);
1751         size_t len = total_len, align = tun->align, linear;
1752         struct virtio_net_hdr gso = { 0 };
1753         struct tun_pcpu_stats *stats;
1754         int good_linear;
1755         int copylen;
1756         bool zerocopy = false;
1757         int err;
1758         u32 rxhash = 0;
1759         int skb_xdp = 1;
1760         bool frags = tun_napi_frags_enabled(tfile);
1761
1762         if (!(tun->flags & IFF_NO_PI)) {
1763                 if (len < sizeof(pi))
1764                         return -EINVAL;
1765                 len -= sizeof(pi);
1766
1767                 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1768                         return -EFAULT;
1769         }
1770
1771         if (tun->flags & IFF_VNET_HDR) {
1772                 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1773
1774                 if (len < vnet_hdr_sz)
1775                         return -EINVAL;
1776                 len -= vnet_hdr_sz;
1777
1778                 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1779                         return -EFAULT;
1780
1781                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1782                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1783                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1784
1785                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1786                         return -EINVAL;
1787                 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1788         }
1789
1790         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1791                 align += NET_IP_ALIGN;
1792                 if (unlikely(len < ETH_HLEN ||
1793                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1794                         return -EINVAL;
1795         }
1796
1797         good_linear = SKB_MAX_HEAD(align);
1798
1799         if (msg_control) {
1800                 struct iov_iter i = *from;
1801
1802                 /* There are 256 bytes to be copied in skb, so there is
1803                  * enough room for skb expand head in case it is used.
1804                  * The rest of the buffer is mapped from userspace.
1805                  */
1806                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1807                 if (copylen > good_linear)
1808                         copylen = good_linear;
1809                 linear = copylen;
1810                 iov_iter_advance(&i, copylen);
1811                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1812                         zerocopy = true;
1813         }
1814
1815         if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1816                 /* For the packet that is not easy to be processed
1817                  * (e.g gso or jumbo packet), we will do it at after
1818                  * skb was created with generic XDP routine.
1819                  */
1820                 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1821                 if (IS_ERR(skb)) {
1822                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1823                         return PTR_ERR(skb);
1824                 }
1825                 if (!skb)
1826                         return total_len;
1827         } else {
1828                 if (!zerocopy) {
1829                         copylen = len;
1830                         if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1831                                 linear = good_linear;
1832                         else
1833                                 linear = tun16_to_cpu(tun, gso.hdr_len);
1834                 }
1835
1836                 if (frags) {
1837                         mutex_lock(&tfile->napi_mutex);
1838                         skb = tun_napi_alloc_frags(tfile, copylen, from);
1839                         /* tun_napi_alloc_frags() enforces a layout for the skb.
1840                          * If zerocopy is enabled, then this layout will be
1841                          * overwritten by zerocopy_sg_from_iter().
1842                          */
1843                         zerocopy = false;
1844                 } else {
1845                         skb = tun_alloc_skb(tfile, align, copylen, linear,
1846                                             noblock);
1847                 }
1848
1849                 if (IS_ERR(skb)) {
1850                         if (PTR_ERR(skb) != -EAGAIN)
1851                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1852                         if (frags)
1853                                 mutex_unlock(&tfile->napi_mutex);
1854                         return PTR_ERR(skb);
1855                 }
1856
1857                 if (zerocopy)
1858                         err = zerocopy_sg_from_iter(skb, from);
1859                 else
1860                         err = skb_copy_datagram_from_iter(skb, 0, from, len);
1861
1862                 if (err) {
1863                         err = -EFAULT;
1864 drop:
1865                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1866                         kfree_skb(skb);
1867                         if (frags) {
1868                                 tfile->napi.skb = NULL;
1869                                 mutex_unlock(&tfile->napi_mutex);
1870                         }
1871
1872                         return err;
1873                 }
1874         }
1875
1876         if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1877                 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1878                 kfree_skb(skb);
1879                 if (frags) {
1880                         tfile->napi.skb = NULL;
1881                         mutex_unlock(&tfile->napi_mutex);
1882                 }
1883
1884                 return -EINVAL;
1885         }
1886
1887         switch (tun->flags & TUN_TYPE_MASK) {
1888         case IFF_TUN:
1889                 if (tun->flags & IFF_NO_PI) {
1890                         u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1891
1892                         switch (ip_version) {
1893                         case 4:
1894                                 pi.proto = htons(ETH_P_IP);
1895                                 break;
1896                         case 6:
1897                                 pi.proto = htons(ETH_P_IPV6);
1898                                 break;
1899                         default:
1900                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1901                                 kfree_skb(skb);
1902                                 return -EINVAL;
1903                         }
1904                 }
1905
1906                 skb_reset_mac_header(skb);
1907                 skb->protocol = pi.proto;
1908                 skb->dev = tun->dev;
1909                 break;
1910         case IFF_TAP:
1911                 if (frags && !pskb_may_pull(skb, ETH_HLEN)) {
1912                         err = -ENOMEM;
1913                         goto drop;
1914                 }
1915                 skb->protocol = eth_type_trans(skb, tun->dev);
1916                 break;
1917         }
1918
1919         /* copy skb_ubuf_info for callback when skb has no error */
1920         if (zerocopy) {
1921                 skb_shinfo(skb)->destructor_arg = msg_control;
1922                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1923                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1924         } else if (msg_control) {
1925                 struct ubuf_info *uarg = msg_control;
1926                 uarg->callback(uarg, false);
1927         }
1928
1929         skb_reset_network_header(skb);
1930         skb_probe_transport_header(skb);
1931         skb_record_rx_queue(skb, tfile->queue_index);
1932
1933         if (skb_xdp) {
1934                 struct bpf_prog *xdp_prog;
1935                 int ret;
1936
1937                 local_bh_disable();
1938                 rcu_read_lock();
1939                 xdp_prog = rcu_dereference(tun->xdp_prog);
1940                 if (xdp_prog) {
1941                         ret = do_xdp_generic(xdp_prog, skb);
1942                         if (ret != XDP_PASS) {
1943                                 rcu_read_unlock();
1944                                 local_bh_enable();
1945                                 if (frags) {
1946                                         tfile->napi.skb = NULL;
1947                                         mutex_unlock(&tfile->napi_mutex);
1948                                 }
1949                                 return total_len;
1950                         }
1951                 }
1952                 rcu_read_unlock();
1953                 local_bh_enable();
1954         }
1955
1956         /* Compute the costly rx hash only if needed for flow updates.
1957          * We may get a very small possibility of OOO during switching, not
1958          * worth to optimize.
1959          */
1960         if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1961             !tfile->detached)
1962                 rxhash = __skb_get_hash_symmetric(skb);
1963
1964         rcu_read_lock();
1965         if (unlikely(!(tun->dev->flags & IFF_UP))) {
1966                 err = -EIO;
1967                 rcu_read_unlock();
1968                 goto drop;
1969         }
1970
1971         if (frags) {
1972                 u32 headlen;
1973
1974                 /* Exercise flow dissector code path. */
1975                 skb_push(skb, ETH_HLEN);
1976                 headlen = eth_get_headlen(tun->dev, skb->data,
1977                                           skb_headlen(skb));
1978
1979                 if (unlikely(headlen > skb_headlen(skb))) {
1980                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1981                         napi_free_frags(&tfile->napi);
1982                         rcu_read_unlock();
1983                         mutex_unlock(&tfile->napi_mutex);
1984                         WARN_ON(1);
1985                         return -ENOMEM;
1986                 }
1987
1988                 local_bh_disable();
1989                 napi_gro_frags(&tfile->napi);
1990                 local_bh_enable();
1991                 mutex_unlock(&tfile->napi_mutex);
1992         } else if (tfile->napi_enabled) {
1993                 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1994                 int queue_len;
1995
1996                 spin_lock_bh(&queue->lock);
1997                 __skb_queue_tail(queue, skb);
1998                 queue_len = skb_queue_len(queue);
1999                 spin_unlock(&queue->lock);
2000
2001                 if (!more || queue_len > NAPI_POLL_WEIGHT)
2002                         napi_schedule(&tfile->napi);
2003
2004                 local_bh_enable();
2005         } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
2006                 tun_rx_batched(tun, tfile, skb, more);
2007         } else {
2008                 netif_rx_ni(skb);
2009         }
2010         rcu_read_unlock();
2011
2012         stats = get_cpu_ptr(tun->pcpu_stats);
2013         u64_stats_update_begin(&stats->syncp);
2014         stats->rx_packets++;
2015         stats->rx_bytes += len;
2016         u64_stats_update_end(&stats->syncp);
2017         put_cpu_ptr(stats);
2018
2019         if (rxhash)
2020                 tun_flow_update(tun, rxhash, tfile);
2021
2022         return total_len;
2023 }
2024
2025 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
2026 {
2027         struct file *file = iocb->ki_filp;
2028         struct tun_file *tfile = file->private_data;
2029         struct tun_struct *tun = tun_get(tfile);
2030         ssize_t result;
2031
2032         if (!tun)
2033                 return -EBADFD;
2034
2035         result = tun_get_user(tun, tfile, NULL, from,
2036                               file->f_flags & O_NONBLOCK, false);
2037
2038         tun_put(tun);
2039         return result;
2040 }
2041
2042 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2043                                 struct tun_file *tfile,
2044                                 struct xdp_frame *xdp_frame,
2045                                 struct iov_iter *iter)
2046 {
2047         int vnet_hdr_sz = 0;
2048         size_t size = xdp_frame->len;
2049         struct tun_pcpu_stats *stats;
2050         size_t ret;
2051
2052         if (tun->flags & IFF_VNET_HDR) {
2053                 struct virtio_net_hdr gso = { 0 };
2054
2055                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2056                 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2057                         return -EINVAL;
2058                 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2059                              sizeof(gso)))
2060                         return -EFAULT;
2061                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2062         }
2063
2064         ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2065
2066         stats = get_cpu_ptr(tun->pcpu_stats);
2067         u64_stats_update_begin(&stats->syncp);
2068         stats->tx_packets++;
2069         stats->tx_bytes += ret;
2070         u64_stats_update_end(&stats->syncp);
2071         put_cpu_ptr(tun->pcpu_stats);
2072
2073         return ret;
2074 }
2075
2076 /* Put packet to the user space buffer */
2077 static ssize_t tun_put_user(struct tun_struct *tun,
2078                             struct tun_file *tfile,
2079                             struct sk_buff *skb,
2080                             struct iov_iter *iter)
2081 {
2082         struct tun_pi pi = { 0, skb->protocol };
2083         struct tun_pcpu_stats *stats;
2084         ssize_t total;
2085         int vlan_offset = 0;
2086         int vlan_hlen = 0;
2087         int vnet_hdr_sz = 0;
2088
2089         if (skb_vlan_tag_present(skb))
2090                 vlan_hlen = VLAN_HLEN;
2091
2092         if (tun->flags & IFF_VNET_HDR)
2093                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2094
2095         total = skb->len + vlan_hlen + vnet_hdr_sz;
2096
2097         if (!(tun->flags & IFF_NO_PI)) {
2098                 if (iov_iter_count(iter) < sizeof(pi))
2099                         return -EINVAL;
2100
2101                 total += sizeof(pi);
2102                 if (iov_iter_count(iter) < total) {
2103                         /* Packet will be striped */
2104                         pi.flags |= TUN_PKT_STRIP;
2105                 }
2106
2107                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2108                         return -EFAULT;
2109         }
2110
2111         if (vnet_hdr_sz) {
2112                 struct virtio_net_hdr gso;
2113
2114                 if (iov_iter_count(iter) < vnet_hdr_sz)
2115                         return -EINVAL;
2116
2117                 if (virtio_net_hdr_from_skb(skb, &gso,
2118                                             tun_is_little_endian(tun), true,
2119                                             vlan_hlen)) {
2120                         struct skb_shared_info *sinfo = skb_shinfo(skb);
2121                         pr_err("unexpected GSO type: "
2122                                "0x%x, gso_size %d, hdr_len %d\n",
2123                                sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2124                                tun16_to_cpu(tun, gso.hdr_len));
2125                         print_hex_dump(KERN_ERR, "tun: ",
2126                                        DUMP_PREFIX_NONE,
2127                                        16, 1, skb->head,
2128                                        min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2129                         WARN_ON_ONCE(1);
2130                         return -EINVAL;
2131                 }
2132
2133                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2134                         return -EFAULT;
2135
2136                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2137         }
2138
2139         if (vlan_hlen) {
2140                 int ret;
2141                 struct veth veth;
2142
2143                 veth.h_vlan_proto = skb->vlan_proto;
2144                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2145
2146                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2147
2148                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2149                 if (ret || !iov_iter_count(iter))
2150                         goto done;
2151
2152                 ret = copy_to_iter(&veth, sizeof(veth), iter);
2153                 if (ret != sizeof(veth) || !iov_iter_count(iter))
2154                         goto done;
2155         }
2156
2157         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2158
2159 done:
2160         /* caller is in process context, */
2161         stats = get_cpu_ptr(tun->pcpu_stats);
2162         u64_stats_update_begin(&stats->syncp);
2163         stats->tx_packets++;
2164         stats->tx_bytes += skb->len + vlan_hlen;
2165         u64_stats_update_end(&stats->syncp);
2166         put_cpu_ptr(tun->pcpu_stats);
2167
2168         return total;
2169 }
2170
2171 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2172 {
2173         DECLARE_WAITQUEUE(wait, current);
2174         void *ptr = NULL;
2175         int error = 0;
2176
2177         ptr = ptr_ring_consume(&tfile->tx_ring);
2178         if (ptr)
2179                 goto out;
2180         if (noblock) {
2181                 error = -EAGAIN;
2182                 goto out;
2183         }
2184
2185         add_wait_queue(&tfile->socket.wq.wait, &wait);
2186
2187         while (1) {
2188                 set_current_state(TASK_INTERRUPTIBLE);
2189                 ptr = ptr_ring_consume(&tfile->tx_ring);
2190                 if (ptr)
2191                         break;
2192                 if (signal_pending(current)) {
2193                         error = -ERESTARTSYS;
2194                         break;
2195                 }
2196                 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2197                         error = -EFAULT;
2198                         break;
2199                 }
2200
2201                 schedule();
2202         }
2203
2204         __set_current_state(TASK_RUNNING);
2205         remove_wait_queue(&tfile->socket.wq.wait, &wait);
2206
2207 out:
2208         *err = error;
2209         return ptr;
2210 }
2211
2212 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2213                            struct iov_iter *to,
2214                            int noblock, void *ptr)
2215 {
2216         ssize_t ret;
2217         int err;
2218
2219         tun_debug(KERN_INFO, tun, "tun_do_read\n");
2220
2221         if (!iov_iter_count(to)) {
2222                 tun_ptr_free(ptr);
2223                 return 0;
2224         }
2225
2226         if (!ptr) {
2227                 /* Read frames from ring */
2228                 ptr = tun_ring_recv(tfile, noblock, &err);
2229                 if (!ptr)
2230                         return err;
2231         }
2232
2233         if (tun_is_xdp_frame(ptr)) {
2234                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2235
2236                 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2237                 xdp_return_frame(xdpf);
2238         } else {
2239                 struct sk_buff *skb = ptr;
2240
2241                 ret = tun_put_user(tun, tfile, skb, to);
2242                 if (unlikely(ret < 0))
2243                         kfree_skb(skb);
2244                 else
2245                         consume_skb(skb);
2246         }
2247
2248         return ret;
2249 }
2250
2251 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2252 {
2253         struct file *file = iocb->ki_filp;
2254         struct tun_file *tfile = file->private_data;
2255         struct tun_struct *tun = tun_get(tfile);
2256         ssize_t len = iov_iter_count(to), ret;
2257
2258         if (!tun)
2259                 return -EBADFD;
2260         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2261         ret = min_t(ssize_t, ret, len);
2262         if (ret > 0)
2263                 iocb->ki_pos = ret;
2264         tun_put(tun);
2265         return ret;
2266 }
2267
2268 static void tun_prog_free(struct rcu_head *rcu)
2269 {
2270         struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2271
2272         bpf_prog_destroy(prog->prog);
2273         kfree(prog);
2274 }
2275
2276 static int __tun_set_ebpf(struct tun_struct *tun,
2277                           struct tun_prog __rcu **prog_p,
2278                           struct bpf_prog *prog)
2279 {
2280         struct tun_prog *old, *new = NULL;
2281
2282         if (prog) {
2283                 new = kmalloc(sizeof(*new), GFP_KERNEL);
2284                 if (!new)
2285                         return -ENOMEM;
2286                 new->prog = prog;
2287         }
2288
2289         spin_lock_bh(&tun->lock);
2290         old = rcu_dereference_protected(*prog_p,
2291                                         lockdep_is_held(&tun->lock));
2292         rcu_assign_pointer(*prog_p, new);
2293         spin_unlock_bh(&tun->lock);
2294
2295         if (old)
2296                 call_rcu(&old->rcu, tun_prog_free);
2297
2298         return 0;
2299 }
2300
2301 static void tun_free_netdev(struct net_device *dev)
2302 {
2303         struct tun_struct *tun = netdev_priv(dev);
2304
2305         BUG_ON(!(list_empty(&tun->disabled)));
2306         free_percpu(tun->pcpu_stats);
2307         tun_flow_uninit(tun);
2308         security_tun_dev_free_security(tun->security);
2309         __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2310         __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2311 }
2312
2313 static void tun_setup(struct net_device *dev)
2314 {
2315         struct tun_struct *tun = netdev_priv(dev);
2316
2317         tun->owner = INVALID_UID;
2318         tun->group = INVALID_GID;
2319         tun_default_link_ksettings(dev, &tun->link_ksettings);
2320
2321         dev->ethtool_ops = &tun_ethtool_ops;
2322         dev->needs_free_netdev = true;
2323         dev->priv_destructor = tun_free_netdev;
2324         /* We prefer our own queue length */
2325         dev->tx_queue_len = TUN_READQ_SIZE;
2326 }
2327
2328 /* Trivial set of netlink ops to allow deleting tun or tap
2329  * device with netlink.
2330  */
2331 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2332                         struct netlink_ext_ack *extack)
2333 {
2334         NL_SET_ERR_MSG(extack,
2335                        "tun/tap creation via rtnetlink is not supported.");
2336         return -EOPNOTSUPP;
2337 }
2338
2339 static size_t tun_get_size(const struct net_device *dev)
2340 {
2341         BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2342         BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2343
2344         return nla_total_size(sizeof(uid_t)) + /* OWNER */
2345                nla_total_size(sizeof(gid_t)) + /* GROUP */
2346                nla_total_size(sizeof(u8)) + /* TYPE */
2347                nla_total_size(sizeof(u8)) + /* PI */
2348                nla_total_size(sizeof(u8)) + /* VNET_HDR */
2349                nla_total_size(sizeof(u8)) + /* PERSIST */
2350                nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2351                nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2352                nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2353                0;
2354 }
2355
2356 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2357 {
2358         struct tun_struct *tun = netdev_priv(dev);
2359
2360         if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2361                 goto nla_put_failure;
2362         if (uid_valid(tun->owner) &&
2363             nla_put_u32(skb, IFLA_TUN_OWNER,
2364                         from_kuid_munged(current_user_ns(), tun->owner)))
2365                 goto nla_put_failure;
2366         if (gid_valid(tun->group) &&
2367             nla_put_u32(skb, IFLA_TUN_GROUP,
2368                         from_kgid_munged(current_user_ns(), tun->group)))
2369                 goto nla_put_failure;
2370         if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2371                 goto nla_put_failure;
2372         if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2373                 goto nla_put_failure;
2374         if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2375                 goto nla_put_failure;
2376         if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2377                        !!(tun->flags & IFF_MULTI_QUEUE)))
2378                 goto nla_put_failure;
2379         if (tun->flags & IFF_MULTI_QUEUE) {
2380                 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2381                         goto nla_put_failure;
2382                 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2383                                 tun->numdisabled))
2384                         goto nla_put_failure;
2385         }
2386
2387         return 0;
2388
2389 nla_put_failure:
2390         return -EMSGSIZE;
2391 }
2392
2393 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2394         .kind           = DRV_NAME,
2395         .priv_size      = sizeof(struct tun_struct),
2396         .setup          = tun_setup,
2397         .validate       = tun_validate,
2398         .get_size       = tun_get_size,
2399         .fill_info      = tun_fill_info,
2400 };
2401
2402 static void tun_sock_write_space(struct sock *sk)
2403 {
2404         struct tun_file *tfile;
2405         wait_queue_head_t *wqueue;
2406
2407         if (!sock_writeable(sk))
2408                 return;
2409
2410         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2411                 return;
2412
2413         wqueue = sk_sleep(sk);
2414         if (wqueue && waitqueue_active(wqueue))
2415                 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2416                                                 EPOLLWRNORM | EPOLLWRBAND);
2417
2418         tfile = container_of(sk, struct tun_file, sk);
2419         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2420 }
2421
2422 static void tun_put_page(struct tun_page *tpage)
2423 {
2424         if (tpage->page)
2425                 __page_frag_cache_drain(tpage->page, tpage->count);
2426 }
2427
2428 static int tun_xdp_one(struct tun_struct *tun,
2429                        struct tun_file *tfile,
2430                        struct xdp_buff *xdp, int *flush,
2431                        struct tun_page *tpage)
2432 {
2433         unsigned int datasize = xdp->data_end - xdp->data;
2434         struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2435         struct virtio_net_hdr *gso = &hdr->gso;
2436         struct tun_pcpu_stats *stats;
2437         struct bpf_prog *xdp_prog;
2438         struct sk_buff *skb = NULL;
2439         u32 rxhash = 0, act;
2440         int buflen = hdr->buflen;
2441         int err = 0;
2442         bool skb_xdp = false;
2443         struct page *page;
2444
2445         xdp_prog = rcu_dereference(tun->xdp_prog);
2446         if (xdp_prog) {
2447                 if (gso->gso_type) {
2448                         skb_xdp = true;
2449                         goto build;
2450                 }
2451                 xdp_set_data_meta_invalid(xdp);
2452                 xdp->rxq = &tfile->xdp_rxq;
2453
2454                 act = bpf_prog_run_xdp(xdp_prog, xdp);
2455                 err = tun_xdp_act(tun, xdp_prog, xdp, act);
2456                 if (err < 0) {
2457                         put_page(virt_to_head_page(xdp->data));
2458                         return err;
2459                 }
2460
2461                 switch (err) {
2462                 case XDP_REDIRECT:
2463                         *flush = true;
2464                         /* fall through */
2465                 case XDP_TX:
2466                         return 0;
2467                 case XDP_PASS:
2468                         break;
2469                 default:
2470                         page = virt_to_head_page(xdp->data);
2471                         if (tpage->page == page) {
2472                                 ++tpage->count;
2473                         } else {
2474                                 tun_put_page(tpage);
2475                                 tpage->page = page;
2476                                 tpage->count = 1;
2477                         }
2478                         return 0;
2479                 }
2480         }
2481
2482 build:
2483         skb = build_skb(xdp->data_hard_start, buflen);
2484         if (!skb) {
2485                 err = -ENOMEM;
2486                 goto out;
2487         }
2488
2489         skb_reserve(skb, xdp->data - xdp->data_hard_start);
2490         skb_put(skb, xdp->data_end - xdp->data);
2491
2492         if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2493                 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
2494                 kfree_skb(skb);
2495                 err = -EINVAL;
2496                 goto out;
2497         }
2498
2499         skb->protocol = eth_type_trans(skb, tun->dev);
2500         skb_reset_network_header(skb);
2501         skb_probe_transport_header(skb);
2502         skb_record_rx_queue(skb, tfile->queue_index);
2503
2504         if (skb_xdp) {
2505                 err = do_xdp_generic(xdp_prog, skb);
2506                 if (err != XDP_PASS)
2507                         goto out;
2508         }
2509
2510         if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2511             !tfile->detached)
2512                 rxhash = __skb_get_hash_symmetric(skb);
2513
2514         netif_receive_skb(skb);
2515
2516         /* No need for get_cpu_ptr() here since this function is
2517          * always called with bh disabled
2518          */
2519         stats = this_cpu_ptr(tun->pcpu_stats);
2520         u64_stats_update_begin(&stats->syncp);
2521         stats->rx_packets++;
2522         stats->rx_bytes += datasize;
2523         u64_stats_update_end(&stats->syncp);
2524
2525         if (rxhash)
2526                 tun_flow_update(tun, rxhash, tfile);
2527
2528 out:
2529         return err;
2530 }
2531
2532 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2533 {
2534         int ret, i;
2535         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2536         struct tun_struct *tun = tun_get(tfile);
2537         struct tun_msg_ctl *ctl = m->msg_control;
2538         struct xdp_buff *xdp;
2539
2540         if (!tun)
2541                 return -EBADFD;
2542
2543         if (ctl && (ctl->type == TUN_MSG_PTR)) {
2544                 struct tun_page tpage;
2545                 int n = ctl->num;
2546                 int flush = 0;
2547
2548                 memset(&tpage, 0, sizeof(tpage));
2549
2550                 local_bh_disable();
2551                 rcu_read_lock();
2552
2553                 for (i = 0; i < n; i++) {
2554                         xdp = &((struct xdp_buff *)ctl->ptr)[i];
2555                         tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2556                 }
2557
2558                 if (flush)
2559                         xdp_do_flush_map();
2560
2561                 rcu_read_unlock();
2562                 local_bh_enable();
2563
2564                 tun_put_page(&tpage);
2565
2566                 ret = total_len;
2567                 goto out;
2568         }
2569
2570         ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2571                            m->msg_flags & MSG_DONTWAIT,
2572                            m->msg_flags & MSG_MORE);
2573 out:
2574         tun_put(tun);
2575         return ret;
2576 }
2577
2578 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2579                        int flags)
2580 {
2581         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2582         struct tun_struct *tun = tun_get(tfile);
2583         void *ptr = m->msg_control;
2584         int ret;
2585
2586         if (!tun) {
2587                 ret = -EBADFD;
2588                 goto out_free;
2589         }
2590
2591         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2592                 ret = -EINVAL;
2593                 goto out_put_tun;
2594         }
2595         if (flags & MSG_ERRQUEUE) {
2596                 ret = sock_recv_errqueue(sock->sk, m, total_len,
2597                                          SOL_PACKET, TUN_TX_TIMESTAMP);
2598                 goto out;
2599         }
2600         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2601         if (ret > (ssize_t)total_len) {
2602                 m->msg_flags |= MSG_TRUNC;
2603                 ret = flags & MSG_TRUNC ? ret : total_len;
2604         }
2605 out:
2606         tun_put(tun);
2607         return ret;
2608
2609 out_put_tun:
2610         tun_put(tun);
2611 out_free:
2612         tun_ptr_free(ptr);
2613         return ret;
2614 }
2615
2616 static int tun_ptr_peek_len(void *ptr)
2617 {
2618         if (likely(ptr)) {
2619                 if (tun_is_xdp_frame(ptr)) {
2620                         struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2621
2622                         return xdpf->len;
2623                 }
2624                 return __skb_array_len_with_tag(ptr);
2625         } else {
2626                 return 0;
2627         }
2628 }
2629
2630 static int tun_peek_len(struct socket *sock)
2631 {
2632         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2633         struct tun_struct *tun;
2634         int ret = 0;
2635
2636         tun = tun_get(tfile);
2637         if (!tun)
2638                 return 0;
2639
2640         ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2641         tun_put(tun);
2642
2643         return ret;
2644 }
2645
2646 /* Ops structure to mimic raw sockets with tun */
2647 static const struct proto_ops tun_socket_ops = {
2648         .peek_len = tun_peek_len,
2649         .sendmsg = tun_sendmsg,
2650         .recvmsg = tun_recvmsg,
2651 };
2652
2653 static struct proto tun_proto = {
2654         .name           = "tun",
2655         .owner          = THIS_MODULE,
2656         .obj_size       = sizeof(struct tun_file),
2657 };
2658
2659 static int tun_flags(struct tun_struct *tun)
2660 {
2661         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2662 }
2663
2664 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2665                               char *buf)
2666 {
2667         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2668         return sprintf(buf, "0x%x\n", tun_flags(tun));
2669 }
2670
2671 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2672                               char *buf)
2673 {
2674         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2675         return uid_valid(tun->owner)?
2676                 sprintf(buf, "%u\n",
2677                         from_kuid_munged(current_user_ns(), tun->owner)):
2678                 sprintf(buf, "-1\n");
2679 }
2680
2681 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2682                               char *buf)
2683 {
2684         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2685         return gid_valid(tun->group) ?
2686                 sprintf(buf, "%u\n",
2687                         from_kgid_munged(current_user_ns(), tun->group)):
2688                 sprintf(buf, "-1\n");
2689 }
2690
2691 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2692 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2693 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2694
2695 static struct attribute *tun_dev_attrs[] = {
2696         &dev_attr_tun_flags.attr,
2697         &dev_attr_owner.attr,
2698         &dev_attr_group.attr,
2699         NULL
2700 };
2701
2702 static const struct attribute_group tun_attr_group = {
2703         .attrs = tun_dev_attrs
2704 };
2705
2706 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2707 {
2708         struct tun_struct *tun;
2709         struct tun_file *tfile = file->private_data;
2710         struct net_device *dev;
2711         int err;
2712
2713         if (tfile->detached)
2714                 return -EINVAL;
2715
2716         if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2717                 if (!capable(CAP_NET_ADMIN))
2718                         return -EPERM;
2719
2720                 if (!(ifr->ifr_flags & IFF_NAPI) ||
2721                     (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2722                         return -EINVAL;
2723         }
2724
2725         dev = __dev_get_by_name(net, ifr->ifr_name);
2726         if (dev) {
2727                 if (ifr->ifr_flags & IFF_TUN_EXCL)
2728                         return -EBUSY;
2729                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2730                         tun = netdev_priv(dev);
2731                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2732                         tun = netdev_priv(dev);
2733                 else
2734                         return -EINVAL;
2735
2736                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2737                     !!(tun->flags & IFF_MULTI_QUEUE))
2738                         return -EINVAL;
2739
2740                 if (tun_not_capable(tun))
2741                         return -EPERM;
2742                 err = security_tun_dev_open(tun->security);
2743                 if (err < 0)
2744                         return err;
2745
2746                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2747                                  ifr->ifr_flags & IFF_NAPI,
2748                                  ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2749                 if (err < 0)
2750                         return err;
2751
2752                 if (tun->flags & IFF_MULTI_QUEUE &&
2753                     (tun->numqueues + tun->numdisabled > 1)) {
2754                         /* One or more queue has already been attached, no need
2755                          * to initialize the device again.
2756                          */
2757                         netdev_state_change(dev);
2758                         return 0;
2759                 }
2760
2761                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2762                               (ifr->ifr_flags & TUN_FEATURES);
2763
2764                 netdev_state_change(dev);
2765         } else {
2766                 char *name;
2767                 unsigned long flags = 0;
2768                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2769                              MAX_TAP_QUEUES : 1;
2770
2771                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2772                         return -EPERM;
2773                 err = security_tun_dev_create();
2774                 if (err < 0)
2775                         return err;
2776
2777                 /* Set dev type */
2778                 if (ifr->ifr_flags & IFF_TUN) {
2779                         /* TUN device */
2780                         flags |= IFF_TUN;
2781                         name = "tun%d";
2782                 } else if (ifr->ifr_flags & IFF_TAP) {
2783                         /* TAP device */
2784                         flags |= IFF_TAP;
2785                         name = "tap%d";
2786                 } else
2787                         return -EINVAL;
2788
2789                 if (*ifr->ifr_name)
2790                         name = ifr->ifr_name;
2791
2792                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2793                                        NET_NAME_UNKNOWN, tun_setup, queues,
2794                                        queues);
2795
2796                 if (!dev)
2797                         return -ENOMEM;
2798                 err = dev_get_valid_name(net, dev, name);
2799                 if (err < 0)
2800                         goto err_free_dev;
2801
2802                 dev_net_set(dev, net);
2803                 dev->rtnl_link_ops = &tun_link_ops;
2804                 dev->ifindex = tfile->ifindex;
2805                 dev->sysfs_groups[0] = &tun_attr_group;
2806
2807                 tun = netdev_priv(dev);
2808                 tun->dev = dev;
2809                 tun->flags = flags;
2810                 tun->txflt.count = 0;
2811                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2812
2813                 tun->align = NET_SKB_PAD;
2814                 tun->filter_attached = false;
2815                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2816                 tun->rx_batched = 0;
2817                 RCU_INIT_POINTER(tun->steering_prog, NULL);
2818
2819                 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2820                 if (!tun->pcpu_stats) {
2821                         err = -ENOMEM;
2822                         goto err_free_dev;
2823                 }
2824
2825                 spin_lock_init(&tun->lock);
2826
2827                 err = security_tun_dev_alloc_security(&tun->security);
2828                 if (err < 0)
2829                         goto err_free_stat;
2830
2831                 tun_net_init(dev);
2832                 tun_flow_init(tun);
2833
2834                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2835                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2836                                    NETIF_F_HW_VLAN_STAG_TX;
2837                 dev->features = dev->hw_features | NETIF_F_LLTX;
2838                 dev->vlan_features = dev->features &
2839                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
2840                                        NETIF_F_HW_VLAN_STAG_TX);
2841
2842                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2843                               (ifr->ifr_flags & TUN_FEATURES);
2844
2845                 INIT_LIST_HEAD(&tun->disabled);
2846                 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI,
2847                                  ifr->ifr_flags & IFF_NAPI_FRAGS, false);
2848                 if (err < 0)
2849                         goto err_free_flow;
2850
2851                 err = register_netdevice(tun->dev);
2852                 if (err < 0)
2853                         goto err_detach;
2854                 /* free_netdev() won't check refcnt, to aovid race
2855                  * with dev_put() we need publish tun after registration.
2856                  */
2857                 rcu_assign_pointer(tfile->tun, tun);
2858         }
2859
2860         netif_carrier_on(tun->dev);
2861
2862         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2863
2864         /* Make sure persistent devices do not get stuck in
2865          * xoff state.
2866          */
2867         if (netif_running(tun->dev))
2868                 netif_tx_wake_all_queues(tun->dev);
2869
2870         strcpy(ifr->ifr_name, tun->dev->name);
2871         return 0;
2872
2873 err_detach:
2874         tun_detach_all(dev);
2875         /* register_netdevice() already called tun_free_netdev() */
2876         goto err_free_dev;
2877
2878 err_free_flow:
2879         tun_flow_uninit(tun);
2880         security_tun_dev_free_security(tun->security);
2881 err_free_stat:
2882         free_percpu(tun->pcpu_stats);
2883 err_free_dev:
2884         free_netdev(dev);
2885         return err;
2886 }
2887
2888 static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2889 {
2890         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2891
2892         strcpy(ifr->ifr_name, tun->dev->name);
2893
2894         ifr->ifr_flags = tun_flags(tun);
2895
2896 }
2897
2898 /* This is like a cut-down ethtool ops, except done via tun fd so no
2899  * privs required. */
2900 static int set_offload(struct tun_struct *tun, unsigned long arg)
2901 {
2902         netdev_features_t features = 0;
2903
2904         if (arg & TUN_F_CSUM) {
2905                 features |= NETIF_F_HW_CSUM;
2906                 arg &= ~TUN_F_CSUM;
2907
2908                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2909                         if (arg & TUN_F_TSO_ECN) {
2910                                 features |= NETIF_F_TSO_ECN;
2911                                 arg &= ~TUN_F_TSO_ECN;
2912                         }
2913                         if (arg & TUN_F_TSO4)
2914                                 features |= NETIF_F_TSO;
2915                         if (arg & TUN_F_TSO6)
2916                                 features |= NETIF_F_TSO6;
2917                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2918                 }
2919
2920                 arg &= ~TUN_F_UFO;
2921         }
2922
2923         /* This gives the user a way to test for new features in future by
2924          * trying to set them. */
2925         if (arg)
2926                 return -EINVAL;
2927
2928         tun->set_features = features;
2929         tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2930         tun->dev->wanted_features |= features;
2931         netdev_update_features(tun->dev);
2932
2933         return 0;
2934 }
2935
2936 static void tun_detach_filter(struct tun_struct *tun, int n)
2937 {
2938         int i;
2939         struct tun_file *tfile;
2940
2941         for (i = 0; i < n; i++) {
2942                 tfile = rtnl_dereference(tun->tfiles[i]);
2943                 lock_sock(tfile->socket.sk);
2944                 sk_detach_filter(tfile->socket.sk);
2945                 release_sock(tfile->socket.sk);
2946         }
2947
2948         tun->filter_attached = false;
2949 }
2950
2951 static int tun_attach_filter(struct tun_struct *tun)
2952 {
2953         int i, ret = 0;
2954         struct tun_file *tfile;
2955
2956         for (i = 0; i < tun->numqueues; i++) {
2957                 tfile = rtnl_dereference(tun->tfiles[i]);
2958                 lock_sock(tfile->socket.sk);
2959                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2960                 release_sock(tfile->socket.sk);
2961                 if (ret) {
2962                         tun_detach_filter(tun, i);
2963                         return ret;
2964                 }
2965         }
2966
2967         tun->filter_attached = true;
2968         return ret;
2969 }
2970
2971 static void tun_set_sndbuf(struct tun_struct *tun)
2972 {
2973         struct tun_file *tfile;
2974         int i;
2975
2976         for (i = 0; i < tun->numqueues; i++) {
2977                 tfile = rtnl_dereference(tun->tfiles[i]);
2978                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2979         }
2980 }
2981
2982 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2983 {
2984         struct tun_file *tfile = file->private_data;
2985         struct tun_struct *tun;
2986         int ret = 0;
2987
2988         rtnl_lock();
2989
2990         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2991                 tun = tfile->detached;
2992                 if (!tun) {
2993                         ret = -EINVAL;
2994                         goto unlock;
2995                 }
2996                 ret = security_tun_dev_attach_queue(tun->security);
2997                 if (ret < 0)
2998                         goto unlock;
2999                 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
3000                                  tun->flags & IFF_NAPI_FRAGS, true);
3001         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
3002                 tun = rtnl_dereference(tfile->tun);
3003                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
3004                         ret = -EINVAL;
3005                 else
3006                         __tun_detach(tfile, false);
3007         } else
3008                 ret = -EINVAL;
3009
3010         if (ret >= 0)
3011                 netdev_state_change(tun->dev);
3012
3013 unlock:
3014         rtnl_unlock();
3015         return ret;
3016 }
3017
3018 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
3019                         void __user *data)
3020 {
3021         struct bpf_prog *prog;
3022         int fd;
3023
3024         if (copy_from_user(&fd, data, sizeof(fd)))
3025                 return -EFAULT;
3026
3027         if (fd == -1) {
3028                 prog = NULL;
3029         } else {
3030                 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
3031                 if (IS_ERR(prog))
3032                         return PTR_ERR(prog);
3033         }
3034
3035         return __tun_set_ebpf(tun, prog_p, prog);
3036 }
3037
3038 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
3039                             unsigned long arg, int ifreq_len)
3040 {
3041         struct tun_file *tfile = file->private_data;
3042         struct net *net = sock_net(&tfile->sk);
3043         struct tun_struct *tun;
3044         void __user* argp = (void __user*)arg;
3045         unsigned int ifindex, carrier;
3046         struct ifreq ifr;
3047         kuid_t owner;
3048         kgid_t group;
3049         int sndbuf;
3050         int vnet_hdr_sz;
3051         int le;
3052         int ret;
3053         bool do_notify = false;
3054
3055         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3056             (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3057                 if (copy_from_user(&ifr, argp, ifreq_len))
3058                         return -EFAULT;
3059         } else {
3060                 memset(&ifr, 0, sizeof(ifr));
3061         }
3062         if (cmd == TUNGETFEATURES) {
3063                 /* Currently this just means: "what IFF flags are valid?".
3064                  * This is needed because we never checked for invalid flags on
3065                  * TUNSETIFF.
3066                  */
3067                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
3068                                 (unsigned int __user*)argp);
3069         } else if (cmd == TUNSETQUEUE) {
3070                 return tun_set_queue(file, &ifr);
3071         } else if (cmd == SIOCGSKNS) {
3072                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3073                         return -EPERM;
3074                 return open_related_ns(&net->ns, get_net_ns);
3075         }
3076
3077         ret = 0;
3078         rtnl_lock();
3079
3080         tun = tun_get(tfile);
3081         if (cmd == TUNSETIFF) {
3082                 ret = -EEXIST;
3083                 if (tun)
3084                         goto unlock;
3085
3086                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3087
3088                 ret = tun_set_iff(net, file, &ifr);
3089
3090                 if (ret)
3091                         goto unlock;
3092
3093                 if (copy_to_user(argp, &ifr, ifreq_len))
3094                         ret = -EFAULT;
3095                 goto unlock;
3096         }
3097         if (cmd == TUNSETIFINDEX) {
3098                 ret = -EPERM;
3099                 if (tun)
3100                         goto unlock;
3101
3102                 ret = -EFAULT;
3103                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3104                         goto unlock;
3105
3106                 ret = 0;
3107                 tfile->ifindex = ifindex;
3108                 goto unlock;
3109         }
3110
3111         ret = -EBADFD;
3112         if (!tun)
3113                 goto unlock;
3114
3115         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
3116
3117         net = dev_net(tun->dev);
3118         ret = 0;
3119         switch (cmd) {
3120         case TUNGETIFF:
3121                 tun_get_iff(tun, &ifr);
3122
3123                 if (tfile->detached)
3124                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
3125                 if (!tfile->socket.sk->sk_filter)
3126                         ifr.ifr_flags |= IFF_NOFILTER;
3127
3128                 if (copy_to_user(argp, &ifr, ifreq_len))
3129                         ret = -EFAULT;
3130                 break;
3131
3132         case TUNSETNOCSUM:
3133                 /* Disable/Enable checksum */
3134
3135                 /* [unimplemented] */
3136                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
3137                           arg ? "disabled" : "enabled");
3138                 break;
3139
3140         case TUNSETPERSIST:
3141                 /* Disable/Enable persist mode. Keep an extra reference to the
3142                  * module to prevent the module being unprobed.
3143                  */
3144                 if (arg && !(tun->flags & IFF_PERSIST)) {
3145                         tun->flags |= IFF_PERSIST;
3146                         __module_get(THIS_MODULE);
3147                         do_notify = true;
3148                 }
3149                 if (!arg && (tun->flags & IFF_PERSIST)) {
3150                         tun->flags &= ~IFF_PERSIST;
3151                         module_put(THIS_MODULE);
3152                         do_notify = true;
3153                 }
3154
3155                 tun_debug(KERN_INFO, tun, "persist %s\n",
3156                           arg ? "enabled" : "disabled");
3157                 break;
3158
3159         case TUNSETOWNER:
3160                 /* Set owner of the device */
3161                 owner = make_kuid(current_user_ns(), arg);
3162                 if (!uid_valid(owner)) {
3163                         ret = -EINVAL;
3164                         break;
3165                 }
3166                 tun->owner = owner;
3167                 do_notify = true;
3168                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
3169                           from_kuid(&init_user_ns, tun->owner));
3170                 break;
3171
3172         case TUNSETGROUP:
3173                 /* Set group of the device */
3174                 group = make_kgid(current_user_ns(), arg);
3175                 if (!gid_valid(group)) {
3176                         ret = -EINVAL;
3177                         break;
3178                 }
3179                 tun->group = group;
3180                 do_notify = true;
3181                 tun_debug(KERN_INFO, tun, "group set to %u\n",
3182                           from_kgid(&init_user_ns, tun->group));
3183                 break;
3184
3185         case TUNSETLINK:
3186                 /* Only allow setting the type when the interface is down */
3187                 if (tun->dev->flags & IFF_UP) {
3188                         tun_debug(KERN_INFO, tun,
3189                                   "Linktype set failed because interface is up\n");
3190                         ret = -EBUSY;
3191                 } else {
3192                         tun->dev->type = (int) arg;
3193                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
3194                                   tun->dev->type);
3195                         ret = 0;
3196                 }
3197                 break;
3198
3199 #ifdef TUN_DEBUG
3200         case TUNSETDEBUG:
3201                 tun->debug = arg;
3202                 break;
3203 #endif
3204         case TUNSETOFFLOAD:
3205                 ret = set_offload(tun, arg);
3206                 break;
3207
3208         case TUNSETTXFILTER:
3209                 /* Can be set only for TAPs */
3210                 ret = -EINVAL;
3211                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3212                         break;
3213                 ret = update_filter(&tun->txflt, (void __user *)arg);
3214                 break;
3215
3216         case SIOCGIFHWADDR:
3217                 /* Get hw address */
3218                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3219                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3220                 if (copy_to_user(argp, &ifr, ifreq_len))
3221                         ret = -EFAULT;
3222                 break;
3223
3224         case SIOCSIFHWADDR:
3225                 /* Set hw address */
3226                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
3227                           ifr.ifr_hwaddr.sa_data);
3228
3229                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr, NULL);
3230                 break;
3231
3232         case TUNGETSNDBUF:
3233                 sndbuf = tfile->socket.sk->sk_sndbuf;
3234                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3235                         ret = -EFAULT;
3236                 break;
3237
3238         case TUNSETSNDBUF:
3239                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3240                         ret = -EFAULT;
3241                         break;
3242                 }
3243                 if (sndbuf <= 0) {
3244                         ret = -EINVAL;
3245                         break;
3246                 }
3247
3248                 tun->sndbuf = sndbuf;
3249                 tun_set_sndbuf(tun);
3250                 break;
3251
3252         case TUNGETVNETHDRSZ:
3253                 vnet_hdr_sz = tun->vnet_hdr_sz;
3254                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3255                         ret = -EFAULT;
3256                 break;
3257
3258         case TUNSETVNETHDRSZ:
3259                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3260                         ret = -EFAULT;
3261                         break;
3262                 }
3263                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3264                         ret = -EINVAL;
3265                         break;
3266                 }
3267
3268                 tun->vnet_hdr_sz = vnet_hdr_sz;
3269                 break;
3270
3271         case TUNGETVNETLE:
3272                 le = !!(tun->flags & TUN_VNET_LE);
3273                 if (put_user(le, (int __user *)argp))
3274                         ret = -EFAULT;
3275                 break;
3276
3277         case TUNSETVNETLE:
3278                 if (get_user(le, (int __user *)argp)) {
3279                         ret = -EFAULT;
3280                         break;
3281                 }
3282                 if (le)
3283                         tun->flags |= TUN_VNET_LE;
3284                 else
3285                         tun->flags &= ~TUN_VNET_LE;
3286                 break;
3287
3288         case TUNGETVNETBE:
3289                 ret = tun_get_vnet_be(tun, argp);
3290                 break;
3291
3292         case TUNSETVNETBE:
3293                 ret = tun_set_vnet_be(tun, argp);
3294                 break;
3295
3296         case TUNATTACHFILTER:
3297                 /* Can be set only for TAPs */
3298                 ret = -EINVAL;
3299                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3300                         break;
3301                 ret = -EFAULT;
3302                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3303                         break;
3304
3305                 ret = tun_attach_filter(tun);
3306                 break;
3307
3308         case TUNDETACHFILTER:
3309                 /* Can be set only for TAPs */
3310                 ret = -EINVAL;
3311                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3312                         break;
3313                 ret = 0;
3314                 tun_detach_filter(tun, tun->numqueues);
3315                 break;
3316
3317         case TUNGETFILTER:
3318                 ret = -EINVAL;
3319                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3320                         break;
3321                 ret = -EFAULT;
3322                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3323                         break;
3324                 ret = 0;
3325                 break;
3326
3327         case TUNSETSTEERINGEBPF:
3328                 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3329                 break;
3330
3331         case TUNSETFILTEREBPF:
3332                 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3333                 break;
3334
3335         case TUNSETCARRIER:
3336                 ret = -EFAULT;
3337                 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3338                         goto unlock;
3339
3340                 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3341                 break;
3342
3343         case TUNGETDEVNETNS:
3344                 ret = -EPERM;
3345                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3346                         goto unlock;
3347                 ret = open_related_ns(&net->ns, get_net_ns);
3348                 break;
3349
3350         default:
3351                 ret = -EINVAL;
3352                 break;
3353         }
3354
3355         if (do_notify)
3356                 netdev_state_change(tun->dev);
3357
3358 unlock:
3359         rtnl_unlock();
3360         if (tun)
3361                 tun_put(tun);
3362         return ret;
3363 }
3364
3365 static long tun_chr_ioctl(struct file *file,
3366                           unsigned int cmd, unsigned long arg)
3367 {
3368         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3369 }
3370
3371 #ifdef CONFIG_COMPAT
3372 static long tun_chr_compat_ioctl(struct file *file,
3373                          unsigned int cmd, unsigned long arg)
3374 {
3375         switch (cmd) {
3376         case TUNSETIFF:
3377         case TUNGETIFF:
3378         case TUNSETTXFILTER:
3379         case TUNGETSNDBUF:
3380         case TUNSETSNDBUF:
3381         case SIOCGIFHWADDR:
3382         case SIOCSIFHWADDR:
3383                 arg = (unsigned long)compat_ptr(arg);
3384                 break;
3385         default:
3386                 arg = (compat_ulong_t)arg;
3387                 break;
3388         }
3389
3390         /*
3391          * compat_ifreq is shorter than ifreq, so we must not access beyond
3392          * the end of that structure. All fields that are used in this
3393          * driver are compatible though, we don't need to convert the
3394          * contents.
3395          */
3396         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3397 }
3398 #endif /* CONFIG_COMPAT */
3399
3400 static int tun_chr_fasync(int fd, struct file *file, int on)
3401 {
3402         struct tun_file *tfile = file->private_data;
3403         int ret;
3404
3405         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3406                 goto out;
3407
3408         if (on) {
3409                 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3410                 tfile->flags |= TUN_FASYNC;
3411         } else
3412                 tfile->flags &= ~TUN_FASYNC;
3413         ret = 0;
3414 out:
3415         return ret;
3416 }
3417
3418 static int tun_chr_open(struct inode *inode, struct file * file)
3419 {
3420         struct net *net = current->nsproxy->net_ns;
3421         struct tun_file *tfile;
3422
3423         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
3424
3425         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3426                                             &tun_proto, 0);
3427         if (!tfile)
3428                 return -ENOMEM;
3429         if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3430                 sk_free(&tfile->sk);
3431                 return -ENOMEM;
3432         }
3433
3434         mutex_init(&tfile->napi_mutex);
3435         RCU_INIT_POINTER(tfile->tun, NULL);
3436         tfile->flags = 0;
3437         tfile->ifindex = 0;
3438
3439         init_waitqueue_head(&tfile->socket.wq.wait);
3440
3441         tfile->socket.file = file;
3442         tfile->socket.ops = &tun_socket_ops;
3443
3444         sock_init_data(&tfile->socket, &tfile->sk);
3445
3446         tfile->sk.sk_write_space = tun_sock_write_space;
3447         tfile->sk.sk_sndbuf = INT_MAX;
3448
3449         file->private_data = tfile;
3450         INIT_LIST_HEAD(&tfile->next);
3451
3452         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3453
3454         return 0;
3455 }
3456
3457 static int tun_chr_close(struct inode *inode, struct file *file)
3458 {
3459         struct tun_file *tfile = file->private_data;
3460
3461         tun_detach(tfile, true);
3462
3463         return 0;
3464 }
3465
3466 #ifdef CONFIG_PROC_FS
3467 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3468 {
3469         struct tun_file *tfile = file->private_data;
3470         struct tun_struct *tun;
3471         struct ifreq ifr;
3472
3473         memset(&ifr, 0, sizeof(ifr));
3474
3475         rtnl_lock();
3476         tun = tun_get(tfile);
3477         if (tun)
3478                 tun_get_iff(tun, &ifr);
3479         rtnl_unlock();
3480
3481         if (tun)
3482                 tun_put(tun);
3483
3484         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3485 }
3486 #endif
3487
3488 static const struct file_operations tun_fops = {
3489         .owner  = THIS_MODULE,
3490         .llseek = no_llseek,
3491         .read_iter  = tun_chr_read_iter,
3492         .write_iter = tun_chr_write_iter,
3493         .poll   = tun_chr_poll,
3494         .unlocked_ioctl = tun_chr_ioctl,
3495 #ifdef CONFIG_COMPAT
3496         .compat_ioctl = tun_chr_compat_ioctl,
3497 #endif
3498         .open   = tun_chr_open,
3499         .release = tun_chr_close,
3500         .fasync = tun_chr_fasync,
3501 #ifdef CONFIG_PROC_FS
3502         .show_fdinfo = tun_chr_show_fdinfo,
3503 #endif
3504 };
3505
3506 static struct miscdevice tun_miscdev = {
3507         .minor = TUN_MINOR,
3508         .name = "tun",
3509         .nodename = "net/tun",
3510         .fops = &tun_fops,
3511 };
3512
3513 /* ethtool interface */
3514
3515 static void tun_default_link_ksettings(struct net_device *dev,
3516                                        struct ethtool_link_ksettings *cmd)
3517 {
3518         ethtool_link_ksettings_zero_link_mode(cmd, supported);
3519         ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3520         cmd->base.speed         = SPEED_10;
3521         cmd->base.duplex        = DUPLEX_FULL;
3522         cmd->base.port          = PORT_TP;
3523         cmd->base.phy_address   = 0;
3524         cmd->base.autoneg       = AUTONEG_DISABLE;
3525 }
3526
3527 static int tun_get_link_ksettings(struct net_device *dev,
3528                                   struct ethtool_link_ksettings *cmd)
3529 {
3530         struct tun_struct *tun = netdev_priv(dev);
3531
3532         memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3533         return 0;
3534 }
3535
3536 static int tun_set_link_ksettings(struct net_device *dev,
3537                                   const struct ethtool_link_ksettings *cmd)
3538 {
3539         struct tun_struct *tun = netdev_priv(dev);
3540
3541         memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3542         return 0;
3543 }
3544
3545 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3546 {
3547         struct tun_struct *tun = netdev_priv(dev);
3548
3549         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3550         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3551
3552         switch (tun->flags & TUN_TYPE_MASK) {
3553         case IFF_TUN:
3554                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3555                 break;
3556         case IFF_TAP:
3557                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3558                 break;
3559         }
3560 }
3561
3562 static u32 tun_get_msglevel(struct net_device *dev)
3563 {
3564 #ifdef TUN_DEBUG
3565         struct tun_struct *tun = netdev_priv(dev);
3566         return tun->debug;
3567 #else
3568         return -EOPNOTSUPP;
3569 #endif
3570 }
3571
3572 static void tun_set_msglevel(struct net_device *dev, u32 value)
3573 {
3574 #ifdef TUN_DEBUG
3575         struct tun_struct *tun = netdev_priv(dev);
3576         tun->debug = value;
3577 #endif
3578 }
3579
3580 static int tun_get_coalesce(struct net_device *dev,
3581                             struct ethtool_coalesce *ec)
3582 {
3583         struct tun_struct *tun = netdev_priv(dev);
3584
3585         ec->rx_max_coalesced_frames = tun->rx_batched;
3586
3587         return 0;
3588 }
3589
3590 static int tun_set_coalesce(struct net_device *dev,
3591                             struct ethtool_coalesce *ec)
3592 {
3593         struct tun_struct *tun = netdev_priv(dev);
3594
3595         if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3596                 tun->rx_batched = NAPI_POLL_WEIGHT;
3597         else
3598                 tun->rx_batched = ec->rx_max_coalesced_frames;
3599
3600         return 0;
3601 }
3602
3603 static const struct ethtool_ops tun_ethtool_ops = {
3604         .get_drvinfo    = tun_get_drvinfo,
3605         .get_msglevel   = tun_get_msglevel,
3606         .set_msglevel   = tun_set_msglevel,
3607         .get_link       = ethtool_op_get_link,
3608         .get_ts_info    = ethtool_op_get_ts_info,
3609         .get_coalesce   = tun_get_coalesce,
3610         .set_coalesce   = tun_set_coalesce,
3611         .get_link_ksettings = tun_get_link_ksettings,
3612         .set_link_ksettings = tun_set_link_ksettings,
3613 };
3614
3615 static int tun_queue_resize(struct tun_struct *tun)
3616 {
3617         struct net_device *dev = tun->dev;
3618         struct tun_file *tfile;
3619         struct ptr_ring **rings;
3620         int n = tun->numqueues + tun->numdisabled;
3621         int ret, i;
3622
3623         rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3624         if (!rings)
3625                 return -ENOMEM;
3626
3627         for (i = 0; i < tun->numqueues; i++) {
3628                 tfile = rtnl_dereference(tun->tfiles[i]);
3629                 rings[i] = &tfile->tx_ring;
3630         }
3631         list_for_each_entry(tfile, &tun->disabled, next)
3632                 rings[i++] = &tfile->tx_ring;
3633
3634         ret = ptr_ring_resize_multiple(rings, n,
3635                                        dev->tx_queue_len, GFP_KERNEL,
3636                                        tun_ptr_free);
3637
3638         kfree(rings);
3639         return ret;
3640 }
3641
3642 static int tun_device_event(struct notifier_block *unused,
3643                             unsigned long event, void *ptr)
3644 {
3645         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3646         struct tun_struct *tun = netdev_priv(dev);
3647         int i;
3648
3649         if (dev->rtnl_link_ops != &tun_link_ops)
3650                 return NOTIFY_DONE;
3651
3652         switch (event) {
3653         case NETDEV_CHANGE_TX_QUEUE_LEN:
3654                 if (tun_queue_resize(tun))
3655                         return NOTIFY_BAD;
3656                 break;
3657         case NETDEV_UP:
3658                 for (i = 0; i < tun->numqueues; i++) {
3659                         struct tun_file *tfile;
3660
3661                         tfile = rtnl_dereference(tun->tfiles[i]);
3662                         tfile->socket.sk->sk_write_space(tfile->socket.sk);
3663                 }
3664                 break;
3665         default:
3666                 break;
3667         }
3668
3669         return NOTIFY_DONE;
3670 }
3671
3672 static struct notifier_block tun_notifier_block __read_mostly = {
3673         .notifier_call  = tun_device_event,
3674 };
3675
3676 static int __init tun_init(void)
3677 {
3678         int ret = 0;
3679
3680         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3681
3682         ret = rtnl_link_register(&tun_link_ops);
3683         if (ret) {
3684                 pr_err("Can't register link_ops\n");
3685                 goto err_linkops;
3686         }
3687
3688         ret = misc_register(&tun_miscdev);
3689         if (ret) {
3690                 pr_err("Can't register misc device %d\n", TUN_MINOR);
3691                 goto err_misc;
3692         }
3693
3694         ret = register_netdevice_notifier(&tun_notifier_block);
3695         if (ret) {
3696                 pr_err("Can't register netdevice notifier\n");
3697                 goto err_notifier;
3698         }
3699
3700         return  0;
3701
3702 err_notifier:
3703         misc_deregister(&tun_miscdev);
3704 err_misc:
3705         rtnl_link_unregister(&tun_link_ops);
3706 err_linkops:
3707         return ret;
3708 }
3709
3710 static void tun_cleanup(void)
3711 {
3712         misc_deregister(&tun_miscdev);
3713         rtnl_link_unregister(&tun_link_ops);
3714         unregister_netdevice_notifier(&tun_notifier_block);
3715 }
3716
3717 /* Get an underlying socket object from tun file.  Returns error unless file is
3718  * attached to a device.  The returned object works like a packet socket, it
3719  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
3720  * holding a reference to the file for as long as the socket is in use. */
3721 struct socket *tun_get_socket(struct file *file)
3722 {
3723         struct tun_file *tfile;
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->socket;
3730 }
3731 EXPORT_SYMBOL_GPL(tun_get_socket);
3732
3733 struct ptr_ring *tun_get_tx_ring(struct file *file)
3734 {
3735         struct tun_file *tfile;
3736
3737         if (file->f_op != &tun_fops)
3738                 return ERR_PTR(-EINVAL);
3739         tfile = file->private_data;
3740         if (!tfile)
3741                 return ERR_PTR(-EBADFD);
3742         return &tfile->tx_ring;
3743 }
3744 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3745
3746 module_init(tun_init);
3747 module_exit(tun_cleanup);
3748 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3749 MODULE_AUTHOR(DRV_COPYRIGHT);
3750 MODULE_LICENSE("GPL");
3751 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3752 MODULE_ALIAS("devname:net/tun");