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_stats_t rx_packets;
 140         u64_stats_t rx_bytes;
 141         u64_stats_t tx_packets;
 142         u64_stats_t 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       = u64_stats_read(&p->rx_packets);
1171                         rxbytes         = u64_stats_read(&p->rx_bytes);
1172                         txpackets       = u64_stats_read(&p->tx_packets);
1173                         txbytes         = u64_stats_read(&p->tx_bytes);
1174                 } while (u64_stats_fetch_retry(&p->syncp, start));
1175
1176                 stats->rx_packets       += rxpackets;
1177                 stats->rx_bytes         += rxbytes;
1178                 stats->tx_packets       += txpackets;
1179                 stats->tx_bytes         += txbytes;
1180
1181                 /* u32 counters */
1182                 rx_dropped      += p->rx_dropped;
1183                 rx_frame_errors += p->rx_frame_errors;
1184                 tx_dropped      += p->tx_dropped;
1185         }
1186         stats->rx_dropped  = rx_dropped;
1187         stats->rx_frame_errors = rx_frame_errors;
1188         stats->tx_dropped = tx_dropped;
1189 }
1190
1191 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1192                        struct netlink_ext_ack *extack)
1193 {
1194         struct tun_struct *tun = netdev_priv(dev);
1195         struct tun_file *tfile;
1196         struct bpf_prog *old_prog;
1197         int i;
1198
1199         old_prog = rtnl_dereference(tun->xdp_prog);
1200         rcu_assign_pointer(tun->xdp_prog, prog);
1201         if (old_prog)
1202                 bpf_prog_put(old_prog);
1203
1204         for (i = 0; i < tun->numqueues; i++) {
1205                 tfile = rtnl_dereference(tun->tfiles[i]);
1206                 if (prog)
1207                         sock_set_flag(&tfile->sk, SOCK_XDP);
1208                 else
1209                         sock_reset_flag(&tfile->sk, SOCK_XDP);
1210         }
1211         list_for_each_entry(tfile, &tun->disabled, next) {
1212                 if (prog)
1213                         sock_set_flag(&tfile->sk, SOCK_XDP);
1214                 else
1215                         sock_reset_flag(&tfile->sk, SOCK_XDP);
1216         }
1217
1218         return 0;
1219 }
1220
1221 static u32 tun_xdp_query(struct net_device *dev)
1222 {
1223         struct tun_struct *tun = netdev_priv(dev);
1224         const struct bpf_prog *xdp_prog;
1225
1226         xdp_prog = rtnl_dereference(tun->xdp_prog);
1227         if (xdp_prog)
1228                 return xdp_prog->aux->id;
1229
1230         return 0;
1231 }
1232
1233 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1234 {
1235         switch (xdp->command) {
1236         case XDP_SETUP_PROG:
1237                 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1238         case XDP_QUERY_PROG:
1239                 xdp->prog_id = tun_xdp_query(dev);
1240                 return 0;
1241         default:
1242                 return -EINVAL;
1243         }
1244 }
1245
1246 static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1247 {
1248         if (new_carrier) {
1249                 struct tun_struct *tun = netdev_priv(dev);
1250
1251                 if (!tun->numqueues)
1252                         return -EPERM;
1253
1254                 netif_carrier_on(dev);
1255         } else {
1256                 netif_carrier_off(dev);
1257         }
1258         return 0;
1259 }
1260
1261 static const struct net_device_ops tun_netdev_ops = {
1262         .ndo_uninit             = tun_net_uninit,
1263         .ndo_open               = tun_net_open,
1264         .ndo_stop               = tun_net_close,
1265         .ndo_start_xmit         = tun_net_xmit,
1266         .ndo_fix_features       = tun_net_fix_features,
1267         .ndo_select_queue       = tun_select_queue,
1268         .ndo_set_rx_headroom    = tun_set_headroom,
1269         .ndo_get_stats64        = tun_net_get_stats64,
1270         .ndo_change_carrier     = tun_net_change_carrier,
1271 };
1272
1273 static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1274 {
1275         /* Notify and wake up reader process */
1276         if (tfile->flags & TUN_FASYNC)
1277                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1278         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1279 }
1280
1281 static int tun_xdp_xmit(struct net_device *dev, int n,
1282                         struct xdp_frame **frames, u32 flags)
1283 {
1284         struct tun_struct *tun = netdev_priv(dev);
1285         struct tun_file *tfile;
1286         u32 numqueues;
1287         int drops = 0;
1288         int cnt = n;
1289         int i;
1290
1291         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1292                 return -EINVAL;
1293
1294         rcu_read_lock();
1295
1296 resample:
1297         numqueues = READ_ONCE(tun->numqueues);
1298         if (!numqueues) {
1299                 rcu_read_unlock();
1300                 return -ENXIO; /* Caller will free/return all frames */
1301         }
1302
1303         tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1304                                             numqueues]);
1305         if (unlikely(!tfile))
1306                 goto resample;
1307
1308         spin_lock(&tfile->tx_ring.producer_lock);
1309         for (i = 0; i < n; i++) {
1310                 struct xdp_frame *xdp = frames[i];
1311                 /* Encode the XDP flag into lowest bit for consumer to differ
1312                  * XDP buffer from sk_buff.
1313                  */
1314                 void *frame = tun_xdp_to_ptr(xdp);
1315
1316                 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1317                         this_cpu_inc(tun->pcpu_stats->tx_dropped);
1318                         xdp_return_frame_rx_napi(xdp);
1319                         drops++;
1320                 }
1321         }
1322         spin_unlock(&tfile->tx_ring.producer_lock);
1323
1324         if (flags & XDP_XMIT_FLUSH)
1325                 __tun_xdp_flush_tfile(tfile);
1326
1327         rcu_read_unlock();
1328         return cnt - drops;
1329 }
1330
1331 static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1332 {
1333         struct xdp_frame *frame = convert_to_xdp_frame(xdp);
1334
1335         if (unlikely(!frame))
1336                 return -EOVERFLOW;
1337
1338         return tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1339 }
1340
1341 static const struct net_device_ops tap_netdev_ops = {
1342         .ndo_uninit             = tun_net_uninit,
1343         .ndo_open               = tun_net_open,
1344         .ndo_stop               = tun_net_close,
1345         .ndo_start_xmit         = tun_net_xmit,
1346         .ndo_fix_features       = tun_net_fix_features,
1347         .ndo_set_rx_mode        = tun_net_mclist,
1348         .ndo_set_mac_address    = eth_mac_addr,
1349         .ndo_validate_addr      = eth_validate_addr,
1350         .ndo_select_queue       = tun_select_queue,
1351         .ndo_features_check     = passthru_features_check,
1352         .ndo_set_rx_headroom    = tun_set_headroom,
1353         .ndo_get_stats64        = tun_net_get_stats64,
1354         .ndo_bpf                = tun_xdp,
1355         .ndo_xdp_xmit           = tun_xdp_xmit,
1356         .ndo_change_carrier     = tun_net_change_carrier,
1357 };
1358
1359 static void tun_flow_init(struct tun_struct *tun)
1360 {
1361         int i;
1362
1363         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1364                 INIT_HLIST_HEAD(&tun->flows[i]);
1365
1366         tun->ageing_time = TUN_FLOW_EXPIRE;
1367         timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1368         mod_timer(&tun->flow_gc_timer,
1369                   round_jiffies_up(jiffies + tun->ageing_time));
1370 }
1371
1372 static void tun_flow_uninit(struct tun_struct *tun)
1373 {
1374         del_timer_sync(&tun->flow_gc_timer);
1375         tun_flow_flush(tun);
1376 }
1377
1378 #define MIN_MTU 68
1379 #define MAX_MTU 65535
1380
1381 /* Initialize net device. */
1382 static void tun_net_init(struct net_device *dev)
1383 {
1384         struct tun_struct *tun = netdev_priv(dev);
1385
1386         switch (tun->flags & TUN_TYPE_MASK) {
1387         case IFF_TUN:
1388                 dev->netdev_ops = &tun_netdev_ops;
1389
1390                 /* Point-to-Point TUN Device */
1391                 dev->hard_header_len = 0;
1392                 dev->addr_len = 0;
1393                 dev->mtu = 1500;
1394
1395                 /* Zero header length */
1396                 dev->type = ARPHRD_NONE;
1397                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1398                 break;
1399
1400         case IFF_TAP:
1401                 dev->netdev_ops = &tap_netdev_ops;
1402                 /* Ethernet TAP Device */
1403                 ether_setup(dev);
1404                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1405                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1406
1407                 eth_hw_addr_random(dev);
1408
1409                 break;
1410         }
1411
1412         dev->min_mtu = MIN_MTU;
1413         dev->max_mtu = MAX_MTU - dev->hard_header_len;
1414 }
1415
1416 static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1417 {
1418         struct sock *sk = tfile->socket.sk;
1419
1420         return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1421 }
1422
1423 /* Character device part */
1424
1425 /* Poll */
1426 static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1427 {
1428         struct tun_file *tfile = file->private_data;
1429         struct tun_struct *tun = tun_get(tfile);
1430         struct sock *sk;
1431         __poll_t mask = 0;
1432
1433         if (!tun)
1434                 return EPOLLERR;
1435
1436         sk = tfile->socket.sk;
1437
1438         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1439
1440         poll_wait(file, sk_sleep(sk), wait);
1441
1442         if (!ptr_ring_empty(&tfile->tx_ring))
1443                 mask |= EPOLLIN | EPOLLRDNORM;
1444
1445         /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1446          * guarantee EPOLLOUT to be raised by either here or
1447          * tun_sock_write_space(). Then process could get notification
1448          * after it writes to a down device and meets -EIO.
1449          */
1450         if (tun_sock_writeable(tun, tfile) ||
1451             (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1452              tun_sock_writeable(tun, tfile)))
1453                 mask |= EPOLLOUT | EPOLLWRNORM;
1454
1455         if (tun->dev->reg_state != NETREG_REGISTERED)
1456                 mask = EPOLLERR;
1457
1458         tun_put(tun);
1459         return mask;
1460 }
1461
1462 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1463                                             size_t len,
1464                                             const struct iov_iter *it)
1465 {
1466         struct sk_buff *skb;
1467         size_t linear;
1468         int err;
1469         int i;
1470
1471         if (it->nr_segs > MAX_SKB_FRAGS + 1)
1472                 return ERR_PTR(-ENOMEM);
1473
1474         local_bh_disable();
1475         skb = napi_get_frags(&tfile->napi);
1476         local_bh_enable();
1477         if (!skb)
1478                 return ERR_PTR(-ENOMEM);
1479
1480         linear = iov_iter_single_seg_count(it);
1481         err = __skb_grow(skb, linear);
1482         if (err)
1483                 goto free;
1484
1485         skb->len = len;
1486         skb->data_len = len - linear;
1487         skb->truesize += skb->data_len;
1488
1489         for (i = 1; i < it->nr_segs; i++) {
1490                 size_t fragsz = it->iov[i].iov_len;
1491                 struct page *page;
1492                 void *frag;
1493
1494                 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1495                         err = -EINVAL;
1496                         goto free;
1497                 }
1498                 frag = netdev_alloc_frag(fragsz);
1499                 if (!frag) {
1500                         err = -ENOMEM;
1501                         goto free;
1502                 }
1503                 page = virt_to_head_page(frag);
1504                 skb_fill_page_desc(skb, i - 1, page,
1505                                    frag - page_address(page), fragsz);
1506         }
1507
1508         return skb;
1509 free:
1510         /* frees skb and all frags allocated with napi_alloc_frag() */
1511         napi_free_frags(&tfile->napi);
1512         return ERR_PTR(err);
1513 }
1514
1515 /* prepad is the amount to reserve at front.  len is length after that.
1516  * linear is a hint as to how much to copy (usually headers). */
1517 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1518                                      size_t prepad, size_t len,
1519                                      size_t linear, int noblock)
1520 {
1521         struct sock *sk = tfile->socket.sk;
1522         struct sk_buff *skb;
1523         int err;
1524
1525         /* Under a page?  Don't bother with paged skb. */
1526         if (prepad + len < PAGE_SIZE || !linear)
1527                 linear = len;
1528
1529         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1530                                    &err, 0);
1531         if (!skb)
1532                 return ERR_PTR(err);
1533
1534         skb_reserve(skb, prepad);
1535         skb_put(skb, linear);
1536         skb->data_len = len - linear;
1537         skb->len += len - linear;
1538
1539         return skb;
1540 }
1541
1542 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1543                            struct sk_buff *skb, int more)
1544 {
1545         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1546         struct sk_buff_head process_queue;
1547         u32 rx_batched = tun->rx_batched;
1548         bool rcv = false;
1549
1550         if (!rx_batched || (!more && skb_queue_empty(queue))) {
1551                 local_bh_disable();
1552                 skb_record_rx_queue(skb, tfile->queue_index);
1553                 netif_receive_skb(skb);
1554                 local_bh_enable();
1555                 return;
1556         }
1557
1558         spin_lock(&queue->lock);
1559         if (!more || skb_queue_len(queue) == rx_batched) {
1560                 __skb_queue_head_init(&process_queue);
1561                 skb_queue_splice_tail_init(queue, &process_queue);
1562                 rcv = true;
1563         } else {
1564                 __skb_queue_tail(queue, skb);
1565         }
1566         spin_unlock(&queue->lock);
1567
1568         if (rcv) {
1569                 struct sk_buff *nskb;
1570
1571                 local_bh_disable();
1572                 while ((nskb = __skb_dequeue(&process_queue))) {
1573                         skb_record_rx_queue(nskb, tfile->queue_index);
1574                         netif_receive_skb(nskb);
1575                 }
1576                 skb_record_rx_queue(skb, tfile->queue_index);
1577                 netif_receive_skb(skb);
1578                 local_bh_enable();
1579         }
1580 }
1581
1582 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1583                               int len, int noblock, bool zerocopy)
1584 {
1585         if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1586                 return false;
1587
1588         if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1589                 return false;
1590
1591         if (!noblock)
1592                 return false;
1593
1594         if (zerocopy)
1595                 return false;
1596
1597         if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1598             SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1599                 return false;
1600
1601         return true;
1602 }
1603
1604 static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
1605                                        struct page_frag *alloc_frag, char *buf,
1606                                        int buflen, int len, int pad)
1607 {
1608         struct sk_buff *skb = build_skb(buf, buflen);
1609
1610         if (!skb)
1611                 return ERR_PTR(-ENOMEM);
1612
1613         skb_reserve(skb, pad);
1614         skb_put(skb, len);
1615         skb_set_owner_w(skb, tfile->socket.sk);
1616
1617         get_page(alloc_frag->page);
1618         alloc_frag->offset += buflen;
1619
1620         return skb;
1621 }
1622
1623 static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1624                        struct xdp_buff *xdp, u32 act)
1625 {
1626         int err;
1627
1628         switch (act) {
1629         case XDP_REDIRECT:
1630                 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1631                 if (err)
1632                         return err;
1633                 break;
1634         case XDP_TX:
1635                 err = tun_xdp_tx(tun->dev, xdp);
1636                 if (err < 0)
1637                         return err;
1638                 break;
1639         case XDP_PASS:
1640                 break;
1641         default:
1642                 bpf_warn_invalid_xdp_action(act);
1643                 /* fall through */
1644         case XDP_ABORTED:
1645                 trace_xdp_exception(tun->dev, xdp_prog, act);
1646                 /* fall through */
1647         case XDP_DROP:
1648                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1649                 break;
1650         }
1651
1652         return act;
1653 }
1654
1655 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1656                                      struct tun_file *tfile,
1657                                      struct iov_iter *from,
1658                                      struct virtio_net_hdr *hdr,
1659                                      int len, int *skb_xdp)
1660 {
1661         struct page_frag *alloc_frag = &current->task_frag;
1662         struct bpf_prog *xdp_prog;
1663         int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1664         char *buf;
1665         size_t copied;
1666         int pad = TUN_RX_PAD;
1667         int err = 0;
1668
1669         rcu_read_lock();
1670         xdp_prog = rcu_dereference(tun->xdp_prog);
1671         if (xdp_prog)
1672                 pad += XDP_PACKET_HEADROOM;
1673         buflen += SKB_DATA_ALIGN(len + pad);
1674         rcu_read_unlock();
1675
1676         alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1677         if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1678                 return ERR_PTR(-ENOMEM);
1679
1680         buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1681         copied = copy_page_from_iter(alloc_frag->page,
1682                                      alloc_frag->offset + pad,
1683                                      len, from);
1684         if (copied != len)
1685                 return ERR_PTR(-EFAULT);
1686
1687         /* There's a small window that XDP may be set after the check
1688          * of xdp_prog above, this should be rare and for simplicity
1689          * we do XDP on skb in case the headroom is not enough.
1690          */
1691         if (hdr->gso_type || !xdp_prog) {
1692                 *skb_xdp = 1;
1693                 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len,
1694                                        pad);
1695         }
1696
1697         *skb_xdp = 0;
1698
1699         local_bh_disable();
1700         rcu_read_lock();
1701         xdp_prog = rcu_dereference(tun->xdp_prog);
1702         if (xdp_prog) {
1703                 struct xdp_buff xdp;
1704                 u32 act;
1705
1706                 xdp.data_hard_start = buf;
1707                 xdp.data = buf + pad;
1708                 xdp_set_data_meta_invalid(&xdp);
1709                 xdp.data_end = xdp.data + len;
1710                 xdp.rxq = &tfile->xdp_rxq;
1711
1712                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1713                 if (act == XDP_REDIRECT || act == XDP_TX) {
1714                         get_page(alloc_frag->page);
1715                         alloc_frag->offset += buflen;
1716                 }
1717                 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1718                 if (err < 0)
1719                         goto err_xdp;
1720                 if (err == XDP_REDIRECT)
1721                         xdp_do_flush();
1722                 if (err != XDP_PASS)
1723                         goto out;
1724
1725                 pad = xdp.data - xdp.data_hard_start;
1726                 len = xdp.data_end - xdp.data;
1727         }
1728         rcu_read_unlock();
1729         local_bh_enable();
1730
1731         return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1732
1733 err_xdp:
1734         put_page(alloc_frag->page);
1735 out:
1736         rcu_read_unlock();
1737         local_bh_enable();
1738         return NULL;
1739 }
1740
1741 /* Get packet from user space buffer */
1742 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1743                             void *msg_control, struct iov_iter *from,
1744                             int noblock, bool more)
1745 {
1746         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1747         struct sk_buff *skb;
1748         size_t total_len = iov_iter_count(from);
1749         size_t len = total_len, align = tun->align, linear;
1750         struct virtio_net_hdr gso = { 0 };
1751         struct tun_pcpu_stats *stats;
1752         int good_linear;
1753         int copylen;
1754         bool zerocopy = false;
1755         int err;
1756         u32 rxhash = 0;
1757         int skb_xdp = 1;
1758         bool frags = tun_napi_frags_enabled(tfile);
1759
1760         if (!(tun->flags & IFF_NO_PI)) {
1761                 if (len < sizeof(pi))
1762                         return -EINVAL;
1763                 len -= sizeof(pi);
1764
1765                 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1766                         return -EFAULT;
1767         }
1768
1769         if (tun->flags & IFF_VNET_HDR) {
1770                 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1771
1772                 if (len < vnet_hdr_sz)
1773                         return -EINVAL;
1774                 len -= vnet_hdr_sz;
1775
1776                 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1777                         return -EFAULT;
1778
1779                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1780                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1781                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1782
1783                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1784                         return -EINVAL;
1785                 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1786         }
1787
1788         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1789                 align += NET_IP_ALIGN;
1790                 if (unlikely(len < ETH_HLEN ||
1791                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1792                         return -EINVAL;
1793         }
1794
1795         good_linear = SKB_MAX_HEAD(align);
1796
1797         if (msg_control) {
1798                 struct iov_iter i = *from;
1799
1800                 /* There are 256 bytes to be copied in skb, so there is
1801                  * enough room for skb expand head in case it is used.
1802                  * The rest of the buffer is mapped from userspace.
1803                  */
1804                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1805                 if (copylen > good_linear)
1806                         copylen = good_linear;
1807                 linear = copylen;
1808                 iov_iter_advance(&i, copylen);
1809                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1810                         zerocopy = true;
1811         }
1812
1813         if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1814                 /* For the packet that is not easy to be processed
1815                  * (e.g gso or jumbo packet), we will do it at after
1816                  * skb was created with generic XDP routine.
1817                  */
1818                 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1819                 if (IS_ERR(skb)) {
1820                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1821                         return PTR_ERR(skb);
1822                 }
1823                 if (!skb)
1824                         return total_len;
1825         } else {
1826                 if (!zerocopy) {
1827                         copylen = len;
1828                         if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1829                                 linear = good_linear;
1830                         else
1831                                 linear = tun16_to_cpu(tun, gso.hdr_len);
1832                 }
1833
1834                 if (frags) {
1835                         mutex_lock(&tfile->napi_mutex);
1836                         skb = tun_napi_alloc_frags(tfile, copylen, from);
1837                         /* tun_napi_alloc_frags() enforces a layout for the skb.
1838                          * If zerocopy is enabled, then this layout will be
1839                          * overwritten by zerocopy_sg_from_iter().
1840                          */
1841                         zerocopy = false;
1842                 } else {
1843                         skb = tun_alloc_skb(tfile, align, copylen, linear,
1844                                             noblock);
1845                 }
1846
1847                 if (IS_ERR(skb)) {
1848                         if (PTR_ERR(skb) != -EAGAIN)
1849                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1850                         if (frags)
1851                                 mutex_unlock(&tfile->napi_mutex);
1852                         return PTR_ERR(skb);
1853                 }
1854
1855                 if (zerocopy)
1856                         err = zerocopy_sg_from_iter(skb, from);
1857                 else
1858                         err = skb_copy_datagram_from_iter(skb, 0, from, len);
1859
1860                 if (err) {
1861                         err = -EFAULT;
1862 drop:
1863                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1864                         kfree_skb(skb);
1865                         if (frags) {
1866                                 tfile->napi.skb = NULL;
1867                                 mutex_unlock(&tfile->napi_mutex);
1868                         }
1869
1870                         return err;
1871                 }
1872         }
1873
1874         if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1875                 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1876                 kfree_skb(skb);
1877                 if (frags) {
1878                         tfile->napi.skb = NULL;
1879                         mutex_unlock(&tfile->napi_mutex);
1880                 }
1881
1882                 return -EINVAL;
1883         }
1884
1885         switch (tun->flags & TUN_TYPE_MASK) {
1886         case IFF_TUN:
1887                 if (tun->flags & IFF_NO_PI) {
1888                         u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1889
1890                         switch (ip_version) {
1891                         case 4:
1892                                 pi.proto = htons(ETH_P_IP);
1893                                 break;
1894                         case 6:
1895                                 pi.proto = htons(ETH_P_IPV6);
1896                                 break;
1897                         default:
1898                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1899                                 kfree_skb(skb);
1900                                 return -EINVAL;
1901                         }
1902                 }
1903
1904                 skb_reset_mac_header(skb);
1905                 skb->protocol = pi.proto;
1906                 skb->dev = tun->dev;
1907                 break;
1908         case IFF_TAP:
1909                 if (!frags)
1910                         skb->protocol = eth_type_trans(skb, tun->dev);
1911                 break;
1912         }
1913
1914         /* copy skb_ubuf_info for callback when skb has no error */
1915         if (zerocopy) {
1916                 skb_shinfo(skb)->destructor_arg = msg_control;
1917                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1918                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1919         } else if (msg_control) {
1920                 struct ubuf_info *uarg = msg_control;
1921                 uarg->callback(uarg, false);
1922         }
1923
1924         skb_reset_network_header(skb);
1925         skb_probe_transport_header(skb);
1926
1927         if (skb_xdp) {
1928                 struct bpf_prog *xdp_prog;
1929                 int ret;
1930
1931                 local_bh_disable();
1932                 rcu_read_lock();
1933                 xdp_prog = rcu_dereference(tun->xdp_prog);
1934                 if (xdp_prog) {
1935                         ret = do_xdp_generic(xdp_prog, skb);
1936                         if (ret != XDP_PASS) {
1937                                 rcu_read_unlock();
1938                                 local_bh_enable();
1939                                 if (frags) {
1940                                         tfile->napi.skb = NULL;
1941                                         mutex_unlock(&tfile->napi_mutex);
1942                                 }
1943                                 return total_len;
1944                         }
1945                 }
1946                 rcu_read_unlock();
1947                 local_bh_enable();
1948         }
1949
1950         /* Compute the costly rx hash only if needed for flow updates.
1951          * We may get a very small possibility of OOO during switching, not
1952          * worth to optimize.
1953          */
1954         if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1955             !tfile->detached)
1956                 rxhash = __skb_get_hash_symmetric(skb);
1957
1958         rcu_read_lock();
1959         if (unlikely(!(tun->dev->flags & IFF_UP))) {
1960                 err = -EIO;
1961                 rcu_read_unlock();
1962                 goto drop;
1963         }
1964
1965         if (frags) {
1966                 /* Exercise flow dissector code path. */
1967                 u32 headlen = eth_get_headlen(tun->dev, skb->data,
1968                                               skb_headlen(skb));
1969
1970                 if (unlikely(headlen > skb_headlen(skb))) {
1971                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1972                         napi_free_frags(&tfile->napi);
1973                         rcu_read_unlock();
1974                         mutex_unlock(&tfile->napi_mutex);
1975                         WARN_ON(1);
1976                         return -ENOMEM;
1977                 }
1978
1979                 local_bh_disable();
1980                 napi_gro_frags(&tfile->napi);
1981                 local_bh_enable();
1982                 mutex_unlock(&tfile->napi_mutex);
1983         } else if (tfile->napi_enabled) {
1984                 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1985                 int queue_len;
1986
1987                 spin_lock_bh(&queue->lock);
1988                 __skb_queue_tail(queue, skb);
1989                 queue_len = skb_queue_len(queue);
1990                 spin_unlock(&queue->lock);
1991
1992                 if (!more || queue_len > NAPI_POLL_WEIGHT)
1993                         napi_schedule(&tfile->napi);
1994
1995                 local_bh_enable();
1996         } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1997                 tun_rx_batched(tun, tfile, skb, more);
1998         } else {
1999                 netif_rx_ni(skb);
2000         }
2001         rcu_read_unlock();
2002
2003         stats = get_cpu_ptr(tun->pcpu_stats);
2004         u64_stats_update_begin(&stats->syncp);
2005         u64_stats_inc(&stats->rx_packets);
2006         u64_stats_add(&stats->rx_bytes, len);
2007         u64_stats_update_end(&stats->syncp);
2008         put_cpu_ptr(stats);
2009
2010         if (rxhash)
2011                 tun_flow_update(tun, rxhash, tfile);
2012
2013         return total_len;
2014 }
2015
2016 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
2017 {
2018         struct file *file = iocb->ki_filp;
2019         struct tun_file *tfile = file->private_data;
2020         struct tun_struct *tun = tun_get(tfile);
2021         ssize_t result;
2022
2023         if (!tun)
2024                 return -EBADFD;
2025
2026         result = tun_get_user(tun, tfile, NULL, from,
2027                               file->f_flags & O_NONBLOCK, false);
2028
2029         tun_put(tun);
2030         return result;
2031 }
2032
2033 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2034                                 struct tun_file *tfile,
2035                                 struct xdp_frame *xdp_frame,
2036                                 struct iov_iter *iter)
2037 {
2038         int vnet_hdr_sz = 0;
2039         size_t size = xdp_frame->len;
2040         struct tun_pcpu_stats *stats;
2041         size_t ret;
2042
2043         if (tun->flags & IFF_VNET_HDR) {
2044                 struct virtio_net_hdr gso = { 0 };
2045
2046                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2047                 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2048                         return -EINVAL;
2049                 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2050                              sizeof(gso)))
2051                         return -EFAULT;
2052                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2053         }
2054
2055         ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2056
2057         stats = get_cpu_ptr(tun->pcpu_stats);
2058         u64_stats_update_begin(&stats->syncp);
2059         u64_stats_inc(&stats->tx_packets);
2060         u64_stats_add(&stats->tx_bytes, ret);
2061         u64_stats_update_end(&stats->syncp);
2062         put_cpu_ptr(tun->pcpu_stats);
2063
2064         return ret;
2065 }
2066
2067 /* Put packet to the user space buffer */
2068 static ssize_t tun_put_user(struct tun_struct *tun,
2069                             struct tun_file *tfile,
2070                             struct sk_buff *skb,
2071                             struct iov_iter *iter)
2072 {
2073         struct tun_pi pi = { 0, skb->protocol };
2074         struct tun_pcpu_stats *stats;
2075         ssize_t total;
2076         int vlan_offset = 0;
2077         int vlan_hlen = 0;
2078         int vnet_hdr_sz = 0;
2079
2080         if (skb_vlan_tag_present(skb))
2081                 vlan_hlen = VLAN_HLEN;
2082
2083         if (tun->flags & IFF_VNET_HDR)
2084                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2085
2086         total = skb->len + vlan_hlen + vnet_hdr_sz;
2087
2088         if (!(tun->flags & IFF_NO_PI)) {
2089                 if (iov_iter_count(iter) < sizeof(pi))
2090                         return -EINVAL;
2091
2092                 total += sizeof(pi);
2093                 if (iov_iter_count(iter) < total) {
2094                         /* Packet will be striped */
2095                         pi.flags |= TUN_PKT_STRIP;
2096                 }
2097
2098                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2099                         return -EFAULT;
2100         }
2101
2102         if (vnet_hdr_sz) {
2103                 struct virtio_net_hdr gso;
2104
2105                 if (iov_iter_count(iter) < vnet_hdr_sz)
2106                         return -EINVAL;
2107
2108                 if (virtio_net_hdr_from_skb(skb, &gso,
2109                                             tun_is_little_endian(tun), true,
2110                                             vlan_hlen)) {
2111                         struct skb_shared_info *sinfo = skb_shinfo(skb);
2112                         pr_err("unexpected GSO type: "
2113                                "0x%x, gso_size %d, hdr_len %d\n",
2114                                sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2115                                tun16_to_cpu(tun, gso.hdr_len));
2116                         print_hex_dump(KERN_ERR, "tun: ",
2117                                        DUMP_PREFIX_NONE,
2118                                        16, 1, skb->head,
2119                                        min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2120                         WARN_ON_ONCE(1);
2121                         return -EINVAL;
2122                 }
2123
2124                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2125                         return -EFAULT;
2126
2127                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2128         }
2129
2130         if (vlan_hlen) {
2131                 int ret;
2132                 struct veth veth;
2133
2134                 veth.h_vlan_proto = skb->vlan_proto;
2135                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2136
2137                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2138
2139                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2140                 if (ret || !iov_iter_count(iter))
2141                         goto done;
2142
2143                 ret = copy_to_iter(&veth, sizeof(veth), iter);
2144                 if (ret != sizeof(veth) || !iov_iter_count(iter))
2145                         goto done;
2146         }
2147
2148         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2149
2150 done:
2151         /* caller is in process context, */
2152         stats = get_cpu_ptr(tun->pcpu_stats);
2153         u64_stats_update_begin(&stats->syncp);
2154         u64_stats_inc(&stats->tx_packets);
2155         u64_stats_add(&stats->tx_bytes, skb->len + vlan_hlen);
2156         u64_stats_update_end(&stats->syncp);
2157         put_cpu_ptr(tun->pcpu_stats);
2158
2159         return total;
2160 }
2161
2162 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2163 {
2164         DECLARE_WAITQUEUE(wait, current);
2165         void *ptr = NULL;
2166         int error = 0;
2167
2168         ptr = ptr_ring_consume(&tfile->tx_ring);
2169         if (ptr)
2170                 goto out;
2171         if (noblock) {
2172                 error = -EAGAIN;
2173                 goto out;
2174         }
2175
2176         add_wait_queue(&tfile->socket.wq.wait, &wait);
2177
2178         while (1) {
2179                 set_current_state(TASK_INTERRUPTIBLE);
2180                 ptr = ptr_ring_consume(&tfile->tx_ring);
2181                 if (ptr)
2182                         break;
2183                 if (signal_pending(current)) {
2184                         error = -ERESTARTSYS;
2185                         break;
2186                 }
2187                 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2188                         error = -EFAULT;
2189                         break;
2190                 }
2191
2192                 schedule();
2193         }
2194
2195         __set_current_state(TASK_RUNNING);
2196         remove_wait_queue(&tfile->socket.wq.wait, &wait);
2197
2198 out:
2199         *err = error;
2200         return ptr;
2201 }
2202
2203 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2204                            struct iov_iter *to,
2205                            int noblock, void *ptr)
2206 {
2207         ssize_t ret;
2208         int err;
2209
2210         tun_debug(KERN_INFO, tun, "tun_do_read\n");
2211
2212         if (!iov_iter_count(to)) {
2213                 tun_ptr_free(ptr);
2214                 return 0;
2215         }
2216
2217         if (!ptr) {
2218                 /* Read frames from ring */
2219                 ptr = tun_ring_recv(tfile, noblock, &err);
2220                 if (!ptr)
2221                         return err;
2222         }
2223
2224         if (tun_is_xdp_frame(ptr)) {
2225                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2226
2227                 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2228                 xdp_return_frame(xdpf);
2229         } else {
2230                 struct sk_buff *skb = ptr;
2231
2232                 ret = tun_put_user(tun, tfile, skb, to);
2233                 if (unlikely(ret < 0))
2234                         kfree_skb(skb);
2235                 else
2236                         consume_skb(skb);
2237         }
2238
2239         return ret;
2240 }
2241
2242 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2243 {
2244         struct file *file = iocb->ki_filp;
2245         struct tun_file *tfile = file->private_data;
2246         struct tun_struct *tun = tun_get(tfile);
2247         ssize_t len = iov_iter_count(to), ret;
2248
2249         if (!tun)
2250                 return -EBADFD;
2251         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2252         ret = min_t(ssize_t, ret, len);
2253         if (ret > 0)
2254                 iocb->ki_pos = ret;
2255         tun_put(tun);
2256         return ret;
2257 }
2258
2259 static void tun_prog_free(struct rcu_head *rcu)
2260 {
2261         struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2262
2263         bpf_prog_destroy(prog->prog);
2264         kfree(prog);
2265 }
2266
2267 static int __tun_set_ebpf(struct tun_struct *tun,
2268                           struct tun_prog __rcu **prog_p,
2269                           struct bpf_prog *prog)
2270 {
2271         struct tun_prog *old, *new = NULL;
2272
2273         if (prog) {
2274                 new = kmalloc(sizeof(*new), GFP_KERNEL);
2275                 if (!new)
2276                         return -ENOMEM;
2277                 new->prog = prog;
2278         }
2279
2280         spin_lock_bh(&tun->lock);
2281         old = rcu_dereference_protected(*prog_p,
2282                                         lockdep_is_held(&tun->lock));
2283         rcu_assign_pointer(*prog_p, new);
2284         spin_unlock_bh(&tun->lock);
2285
2286         if (old)
2287                 call_rcu(&old->rcu, tun_prog_free);
2288
2289         return 0;
2290 }
2291
2292 static void tun_free_netdev(struct net_device *dev)
2293 {
2294         struct tun_struct *tun = netdev_priv(dev);
2295
2296         BUG_ON(!(list_empty(&tun->disabled)));
2297
2298         free_percpu(tun->pcpu_stats);
2299         /* We clear pcpu_stats so that tun_set_iff() can tell if
2300          * tun_free_netdev() has been called from register_netdevice().
2301          */
2302         tun->pcpu_stats = NULL;
2303
2304         tun_flow_uninit(tun);
2305         security_tun_dev_free_security(tun->security);
2306         __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2307         __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2308 }
2309
2310 static void tun_setup(struct net_device *dev)
2311 {
2312         struct tun_struct *tun = netdev_priv(dev);
2313
2314         tun->owner = INVALID_UID;
2315         tun->group = INVALID_GID;
2316         tun_default_link_ksettings(dev, &tun->link_ksettings);
2317
2318         dev->ethtool_ops = &tun_ethtool_ops;
2319         dev->needs_free_netdev = true;
2320         dev->priv_destructor = tun_free_netdev;
2321         /* We prefer our own queue length */
2322         dev->tx_queue_len = TUN_READQ_SIZE;
2323 }
2324
2325 /* Trivial set of netlink ops to allow deleting tun or tap
2326  * device with netlink.
2327  */
2328 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2329                         struct netlink_ext_ack *extack)
2330 {
2331         NL_SET_ERR_MSG(extack,
2332                        "tun/tap creation via rtnetlink is not supported.");
2333         return -EOPNOTSUPP;
2334 }
2335
2336 static size_t tun_get_size(const struct net_device *dev)
2337 {
2338         BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2339         BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2340
2341         return nla_total_size(sizeof(uid_t)) + /* OWNER */
2342                nla_total_size(sizeof(gid_t)) + /* GROUP */
2343                nla_total_size(sizeof(u8)) + /* TYPE */
2344                nla_total_size(sizeof(u8)) + /* PI */
2345                nla_total_size(sizeof(u8)) + /* VNET_HDR */
2346                nla_total_size(sizeof(u8)) + /* PERSIST */
2347                nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2348                nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2349                nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2350                0;
2351 }
2352
2353 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2354 {
2355         struct tun_struct *tun = netdev_priv(dev);
2356
2357         if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2358                 goto nla_put_failure;
2359         if (uid_valid(tun->owner) &&
2360             nla_put_u32(skb, IFLA_TUN_OWNER,
2361                         from_kuid_munged(current_user_ns(), tun->owner)))
2362                 goto nla_put_failure;
2363         if (gid_valid(tun->group) &&
2364             nla_put_u32(skb, IFLA_TUN_GROUP,
2365                         from_kgid_munged(current_user_ns(), tun->group)))
2366                 goto nla_put_failure;
2367         if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2368                 goto nla_put_failure;
2369         if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2370                 goto nla_put_failure;
2371         if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2372                 goto nla_put_failure;
2373         if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2374                        !!(tun->flags & IFF_MULTI_QUEUE)))
2375                 goto nla_put_failure;
2376         if (tun->flags & IFF_MULTI_QUEUE) {
2377                 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2378                         goto nla_put_failure;
2379                 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2380                                 tun->numdisabled))
2381                         goto nla_put_failure;
2382         }
2383
2384         return 0;
2385
2386 nla_put_failure:
2387         return -EMSGSIZE;
2388 }
2389
2390 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2391         .kind           = DRV_NAME,
2392         .priv_size      = sizeof(struct tun_struct),
2393         .setup          = tun_setup,
2394         .validate       = tun_validate,
2395         .get_size       = tun_get_size,
2396         .fill_info      = tun_fill_info,
2397 };
2398
2399 static void tun_sock_write_space(struct sock *sk)
2400 {
2401         struct tun_file *tfile;
2402         wait_queue_head_t *wqueue;
2403
2404         if (!sock_writeable(sk))
2405                 return;
2406
2407         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2408                 return;
2409
2410         wqueue = sk_sleep(sk);
2411         if (wqueue && waitqueue_active(wqueue))
2412                 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2413                                                 EPOLLWRNORM | EPOLLWRBAND);
2414
2415         tfile = container_of(sk, struct tun_file, sk);
2416         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2417 }
2418
2419 static void tun_put_page(struct tun_page *tpage)
2420 {
2421         if (tpage->page)
2422                 __page_frag_cache_drain(tpage->page, tpage->count);
2423 }
2424
2425 static int tun_xdp_one(struct tun_struct *tun,
2426                        struct tun_file *tfile,
2427                        struct xdp_buff *xdp, int *flush,
2428                        struct tun_page *tpage)
2429 {
2430         unsigned int datasize = xdp->data_end - xdp->data;
2431         struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2432         struct virtio_net_hdr *gso = &hdr->gso;
2433         struct tun_pcpu_stats *stats;
2434         struct bpf_prog *xdp_prog;
2435         struct sk_buff *skb = NULL;
2436         u32 rxhash = 0, act;
2437         int buflen = hdr->buflen;
2438         int err = 0;
2439         bool skb_xdp = false;
2440         struct page *page;
2441
2442         xdp_prog = rcu_dereference(tun->xdp_prog);
2443         if (xdp_prog) {
2444                 if (gso->gso_type) {
2445                         skb_xdp = true;
2446                         goto build;
2447                 }
2448                 xdp_set_data_meta_invalid(xdp);
2449                 xdp->rxq = &tfile->xdp_rxq;
2450
2451                 act = bpf_prog_run_xdp(xdp_prog, xdp);
2452                 err = tun_xdp_act(tun, xdp_prog, xdp, act);
2453                 if (err < 0) {
2454                         put_page(virt_to_head_page(xdp->data));
2455                         return err;
2456                 }
2457
2458                 switch (err) {
2459                 case XDP_REDIRECT:
2460                         *flush = true;
2461                         /* fall through */
2462                 case XDP_TX:
2463                         return 0;
2464                 case XDP_PASS:
2465                         break;
2466                 default:
2467                         page = virt_to_head_page(xdp->data);
2468                         if (tpage->page == page) {
2469                                 ++tpage->count;
2470                         } else {
2471                                 tun_put_page(tpage);
2472                                 tpage->page = page;
2473                                 tpage->count = 1;
2474                         }
2475                         return 0;
2476                 }
2477         }
2478
2479 build:
2480         skb = build_skb(xdp->data_hard_start, buflen);
2481         if (!skb) {
2482                 err = -ENOMEM;
2483                 goto out;
2484         }
2485
2486         skb_reserve(skb, xdp->data - xdp->data_hard_start);
2487         skb_put(skb, xdp->data_end - xdp->data);
2488
2489         if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2490                 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
2491                 kfree_skb(skb);
2492                 err = -EINVAL;
2493                 goto out;
2494         }
2495
2496         skb->protocol = eth_type_trans(skb, tun->dev);
2497         skb_reset_network_header(skb);
2498         skb_probe_transport_header(skb);
2499
2500         if (skb_xdp) {
2501                 err = do_xdp_generic(xdp_prog, skb);
2502                 if (err != XDP_PASS)
2503                         goto out;
2504         }
2505
2506         if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2507             !tfile->detached)
2508                 rxhash = __skb_get_hash_symmetric(skb);
2509
2510         skb_record_rx_queue(skb, tfile->queue_index);
2511         netif_receive_skb(skb);
2512
2513         /* No need for get_cpu_ptr() here since this function is
2514          * always called with bh disabled
2515          */
2516         stats = this_cpu_ptr(tun->pcpu_stats);
2517         u64_stats_update_begin(&stats->syncp);
2518         u64_stats_inc(&stats->rx_packets);
2519         u64_stats_add(&stats->rx_bytes, datasize);
2520         u64_stats_update_end(&stats->syncp);
2521
2522         if (rxhash)
2523                 tun_flow_update(tun, rxhash, tfile);
2524
2525 out:
2526         return err;
2527 }
2528
2529 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2530 {
2531         int ret, i;
2532         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2533         struct tun_struct *tun = tun_get(tfile);
2534         struct tun_msg_ctl *ctl = m->msg_control;
2535         struct xdp_buff *xdp;
2536
2537         if (!tun)
2538                 return -EBADFD;
2539
2540         if (ctl && (ctl->type == TUN_MSG_PTR)) {
2541                 struct tun_page tpage;
2542                 int n = ctl->num;
2543                 int flush = 0;
2544
2545                 memset(&tpage, 0, sizeof(tpage));
2546
2547                 local_bh_disable();
2548                 rcu_read_lock();
2549
2550                 for (i = 0; i < n; i++) {
2551                         xdp = &((struct xdp_buff *)ctl->ptr)[i];
2552                         tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2553                 }
2554
2555                 if (flush)
2556                         xdp_do_flush();
2557
2558                 rcu_read_unlock();
2559                 local_bh_enable();
2560
2561                 tun_put_page(&tpage);
2562
2563                 ret = total_len;
2564                 goto out;
2565         }
2566
2567         ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2568                            m->msg_flags & MSG_DONTWAIT,
2569                            m->msg_flags & MSG_MORE);
2570 out:
2571         tun_put(tun);
2572         return ret;
2573 }
2574
2575 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2576                        int flags)
2577 {
2578         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2579         struct tun_struct *tun = tun_get(tfile);
2580         void *ptr = m->msg_control;
2581         int ret;
2582
2583         if (!tun) {
2584                 ret = -EBADFD;
2585                 goto out_free;
2586         }
2587
2588         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2589                 ret = -EINVAL;
2590                 goto out_put_tun;
2591         }
2592         if (flags & MSG_ERRQUEUE) {
2593                 ret = sock_recv_errqueue(sock->sk, m, total_len,
2594                                          SOL_PACKET, TUN_TX_TIMESTAMP);
2595                 goto out;
2596         }
2597         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2598         if (ret > (ssize_t)total_len) {
2599                 m->msg_flags |= MSG_TRUNC;
2600                 ret = flags & MSG_TRUNC ? ret : total_len;
2601         }
2602 out:
2603         tun_put(tun);
2604         return ret;
2605
2606 out_put_tun:
2607         tun_put(tun);
2608 out_free:
2609         tun_ptr_free(ptr);
2610         return ret;
2611 }
2612
2613 static int tun_ptr_peek_len(void *ptr)
2614 {
2615         if (likely(ptr)) {
2616                 if (tun_is_xdp_frame(ptr)) {
2617                         struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2618
2619                         return xdpf->len;
2620                 }
2621                 return __skb_array_len_with_tag(ptr);
2622         } else {
2623                 return 0;
2624         }
2625 }
2626
2627 static int tun_peek_len(struct socket *sock)
2628 {
2629         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2630         struct tun_struct *tun;
2631         int ret = 0;
2632
2633         tun = tun_get(tfile);
2634         if (!tun)
2635                 return 0;
2636
2637         ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2638         tun_put(tun);
2639
2640         return ret;
2641 }
2642
2643 /* Ops structure to mimic raw sockets with tun */
2644 static const struct proto_ops tun_socket_ops = {
2645         .peek_len = tun_peek_len,
2646         .sendmsg = tun_sendmsg,
2647         .recvmsg = tun_recvmsg,
2648 };
2649
2650 static struct proto tun_proto = {
2651         .name           = "tun",
2652         .owner          = THIS_MODULE,
2653         .obj_size       = sizeof(struct tun_file),
2654 };
2655
2656 static int tun_flags(struct tun_struct *tun)
2657 {
2658         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2659 }
2660
2661 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2662                               char *buf)
2663 {
2664         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2665         return sprintf(buf, "0x%x\n", tun_flags(tun));
2666 }
2667
2668 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2669                               char *buf)
2670 {
2671         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2672         return uid_valid(tun->owner)?
2673                 sprintf(buf, "%u\n",
2674                         from_kuid_munged(current_user_ns(), tun->owner)):
2675                 sprintf(buf, "-1\n");
2676 }
2677
2678 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2679                               char *buf)
2680 {
2681         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2682         return gid_valid(tun->group) ?
2683                 sprintf(buf, "%u\n",
2684                         from_kgid_munged(current_user_ns(), tun->group)):
2685                 sprintf(buf, "-1\n");
2686 }
2687
2688 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2689 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2690 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2691
2692 static struct attribute *tun_dev_attrs[] = {
2693         &dev_attr_tun_flags.attr,
2694         &dev_attr_owner.attr,
2695         &dev_attr_group.attr,
2696         NULL
2697 };
2698
2699 static const struct attribute_group tun_attr_group = {
2700         .attrs = tun_dev_attrs
2701 };
2702
2703 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2704 {
2705         struct tun_struct *tun;
2706         struct tun_file *tfile = file->private_data;
2707         struct net_device *dev;
2708         int err;
2709
2710         if (tfile->detached)
2711                 return -EINVAL;
2712
2713         if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2714                 if (!capable(CAP_NET_ADMIN))
2715                         return -EPERM;
2716
2717                 if (!(ifr->ifr_flags & IFF_NAPI) ||
2718                     (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2719                         return -EINVAL;
2720         }
2721
2722         dev = __dev_get_by_name(net, ifr->ifr_name);
2723         if (dev) {
2724                 if (ifr->ifr_flags & IFF_TUN_EXCL)
2725                         return -EBUSY;
2726                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2727                         tun = netdev_priv(dev);
2728                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2729                         tun = netdev_priv(dev);
2730                 else
2731                         return -EINVAL;
2732
2733                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2734                     !!(tun->flags & IFF_MULTI_QUEUE))
2735                         return -EINVAL;
2736
2737                 if (tun_not_capable(tun))
2738                         return -EPERM;
2739                 err = security_tun_dev_open(tun->security);
2740                 if (err < 0)
2741                         return err;
2742
2743                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2744                                  ifr->ifr_flags & IFF_NAPI,
2745                                  ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2746                 if (err < 0)
2747                         return err;
2748
2749                 if (tun->flags & IFF_MULTI_QUEUE &&
2750                     (tun->numqueues + tun->numdisabled > 1)) {
2751                         /* One or more queue has already been attached, no need
2752                          * to initialize the device again.
2753                          */
2754                         netdev_state_change(dev);
2755                         return 0;
2756                 }
2757
2758                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2759                               (ifr->ifr_flags & TUN_FEATURES);
2760
2761                 netdev_state_change(dev);
2762         } else {
2763                 char *name;
2764                 unsigned long flags = 0;
2765                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2766                              MAX_TAP_QUEUES : 1;
2767
2768                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2769                         return -EPERM;
2770                 err = security_tun_dev_create();
2771                 if (err < 0)
2772                         return err;
2773
2774                 /* Set dev type */
2775                 if (ifr->ifr_flags & IFF_TUN) {
2776                         /* TUN device */
2777                         flags |= IFF_TUN;
2778                         name = "tun%d";
2779                 } else if (ifr->ifr_flags & IFF_TAP) {
2780                         /* TAP device */
2781                         flags |= IFF_TAP;
2782                         name = "tap%d";
2783                 } else
2784                         return -EINVAL;
2785
2786                 if (*ifr->ifr_name)
2787                         name = ifr->ifr_name;
2788
2789                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2790                                        NET_NAME_UNKNOWN, tun_setup, queues,
2791                                        queues);
2792
2793                 if (!dev)
2794                         return -ENOMEM;
2795
2796                 dev_net_set(dev, net);
2797                 dev->rtnl_link_ops = &tun_link_ops;
2798                 dev->ifindex = tfile->ifindex;
2799                 dev->sysfs_groups[0] = &tun_attr_group;
2800
2801                 tun = netdev_priv(dev);
2802                 tun->dev = dev;
2803                 tun->flags = flags;
2804                 tun->txflt.count = 0;
2805                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2806
2807                 tun->align = NET_SKB_PAD;
2808                 tun->filter_attached = false;
2809                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2810                 tun->rx_batched = 0;
2811                 RCU_INIT_POINTER(tun->steering_prog, NULL);
2812
2813                 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2814                 if (!tun->pcpu_stats) {
2815                         err = -ENOMEM;
2816                         goto err_free_dev;
2817                 }
2818
2819                 spin_lock_init(&tun->lock);
2820
2821                 err = security_tun_dev_alloc_security(&tun->security);
2822                 if (err < 0)
2823                         goto err_free_stat;
2824
2825                 tun_net_init(dev);
2826                 tun_flow_init(tun);
2827
2828                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2829                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2830                                    NETIF_F_HW_VLAN_STAG_TX;
2831                 dev->features = dev->hw_features | NETIF_F_LLTX;
2832                 dev->vlan_features = dev->features &
2833                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
2834                                        NETIF_F_HW_VLAN_STAG_TX);
2835
2836                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2837                               (ifr->ifr_flags & TUN_FEATURES);
2838
2839                 INIT_LIST_HEAD(&tun->disabled);
2840                 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI,
2841                                  ifr->ifr_flags & IFF_NAPI_FRAGS, false);
2842                 if (err < 0)
2843                         goto err_free_flow;
2844
2845                 err = register_netdevice(tun->dev);
2846                 if (err < 0)
2847                         goto err_detach;
2848                 /* free_netdev() won't check refcnt, to aovid race
2849                  * with dev_put() we need publish tun after registration.
2850                  */
2851                 rcu_assign_pointer(tfile->tun, tun);
2852         }
2853
2854         netif_carrier_on(tun->dev);
2855
2856         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2857
2858         /* Make sure persistent devices do not get stuck in
2859          * xoff state.
2860          */
2861         if (netif_running(tun->dev))
2862                 netif_tx_wake_all_queues(tun->dev);
2863
2864         strcpy(ifr->ifr_name, tun->dev->name);
2865         return 0;
2866
2867 err_detach:
2868         tun_detach_all(dev);
2869         /* We are here because register_netdevice() has failed.
2870          * If register_netdevice() already called tun_free_netdev()
2871          * while dealing with the error, tun->pcpu_stats has been cleared.
2872          */
2873         if (!tun->pcpu_stats)
2874                 goto err_free_dev;
2875
2876 err_free_flow:
2877         tun_flow_uninit(tun);
2878         security_tun_dev_free_security(tun->security);
2879 err_free_stat:
2880         free_percpu(tun->pcpu_stats);
2881 err_free_dev:
2882         free_netdev(dev);
2883         return err;
2884 }
2885
2886 static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2887 {
2888         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2889
2890         strcpy(ifr->ifr_name, tun->dev->name);
2891
2892         ifr->ifr_flags = tun_flags(tun);
2893
2894 }
2895
2896 /* This is like a cut-down ethtool ops, except done via tun fd so no
2897  * privs required. */
2898 static int set_offload(struct tun_struct *tun, unsigned long arg)
2899 {
2900         netdev_features_t features = 0;
2901
2902         if (arg & TUN_F_CSUM) {
2903                 features |= NETIF_F_HW_CSUM;
2904                 arg &= ~TUN_F_CSUM;
2905
2906                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2907                         if (arg & TUN_F_TSO_ECN) {
2908                                 features |= NETIF_F_TSO_ECN;
2909                                 arg &= ~TUN_F_TSO_ECN;
2910                         }
2911                         if (arg & TUN_F_TSO4)
2912                                 features |= NETIF_F_TSO;
2913                         if (arg & TUN_F_TSO6)
2914                                 features |= NETIF_F_TSO6;
2915                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2916                 }
2917
2918                 arg &= ~TUN_F_UFO;
2919         }
2920
2921         /* This gives the user a way to test for new features in future by
2922          * trying to set them. */
2923         if (arg)
2924                 return -EINVAL;
2925
2926         tun->set_features = features;
2927         tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2928         tun->dev->wanted_features |= features;
2929         netdev_update_features(tun->dev);
2930
2931         return 0;
2932 }
2933
2934 static void tun_detach_filter(struct tun_struct *tun, int n)
2935 {
2936         int i;
2937         struct tun_file *tfile;
2938
2939         for (i = 0; i < n; i++) {
2940                 tfile = rtnl_dereference(tun->tfiles[i]);
2941                 lock_sock(tfile->socket.sk);
2942                 sk_detach_filter(tfile->socket.sk);
2943                 release_sock(tfile->socket.sk);
2944         }
2945
2946         tun->filter_attached = false;
2947 }
2948
2949 static int tun_attach_filter(struct tun_struct *tun)
2950 {
2951         int i, ret = 0;
2952         struct tun_file *tfile;
2953
2954         for (i = 0; i < tun->numqueues; i++) {
2955                 tfile = rtnl_dereference(tun->tfiles[i]);
2956                 lock_sock(tfile->socket.sk);
2957                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2958                 release_sock(tfile->socket.sk);
2959                 if (ret) {
2960                         tun_detach_filter(tun, i);
2961                         return ret;
2962                 }
2963         }
2964
2965         tun->filter_attached = true;
2966         return ret;
2967 }
2968
2969 static void tun_set_sndbuf(struct tun_struct *tun)
2970 {
2971         struct tun_file *tfile;
2972         int i;
2973
2974         for (i = 0; i < tun->numqueues; i++) {
2975                 tfile = rtnl_dereference(tun->tfiles[i]);
2976                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2977         }
2978 }
2979
2980 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2981 {
2982         struct tun_file *tfile = file->private_data;
2983         struct tun_struct *tun;
2984         int ret = 0;
2985
2986         rtnl_lock();
2987
2988         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2989                 tun = tfile->detached;
2990                 if (!tun) {
2991                         ret = -EINVAL;
2992                         goto unlock;
2993                 }
2994                 ret = security_tun_dev_attach_queue(tun->security);
2995                 if (ret < 0)
2996                         goto unlock;
2997                 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2998                                  tun->flags & IFF_NAPI_FRAGS, true);
2999         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
3000                 tun = rtnl_dereference(tfile->tun);
3001                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
3002                         ret = -EINVAL;
3003                 else
3004                         __tun_detach(tfile, false);
3005         } else
3006                 ret = -EINVAL;
3007
3008         if (ret >= 0)
3009                 netdev_state_change(tun->dev);
3010
3011 unlock:
3012         rtnl_unlock();
3013         return ret;
3014 }
3015
3016 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
3017                         void __user *data)
3018 {
3019         struct bpf_prog *prog;
3020         int fd;
3021
3022         if (copy_from_user(&fd, data, sizeof(fd)))
3023                 return -EFAULT;
3024
3025         if (fd == -1) {
3026                 prog = NULL;
3027         } else {
3028                 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
3029                 if (IS_ERR(prog))
3030                         return PTR_ERR(prog);
3031         }
3032
3033         return __tun_set_ebpf(tun, prog_p, prog);
3034 }
3035
3036 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
3037                             unsigned long arg, int ifreq_len)
3038 {
3039         struct tun_file *tfile = file->private_data;
3040         struct net *net = sock_net(&tfile->sk);
3041         struct tun_struct *tun;
3042         void __user* argp = (void __user*)arg;
3043         unsigned int ifindex, carrier;
3044         struct ifreq ifr;
3045         kuid_t owner;
3046         kgid_t group;
3047         int sndbuf;
3048         int vnet_hdr_sz;
3049         int le;
3050         int ret;
3051         bool do_notify = false;
3052
3053         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3054             (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3055                 if (copy_from_user(&ifr, argp, ifreq_len))
3056                         return -EFAULT;
3057         } else {
3058                 memset(&ifr, 0, sizeof(ifr));
3059         }
3060         if (cmd == TUNGETFEATURES) {
3061                 /* Currently this just means: "what IFF flags are valid?".
3062                  * This is needed because we never checked for invalid flags on
3063                  * TUNSETIFF.
3064                  */
3065                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
3066                                 (unsigned int __user*)argp);
3067         } else if (cmd == TUNSETQUEUE) {
3068                 return tun_set_queue(file, &ifr);
3069         } else if (cmd == SIOCGSKNS) {
3070                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3071                         return -EPERM;
3072                 return open_related_ns(&net->ns, get_net_ns);
3073         }
3074
3075         ret = 0;
3076         rtnl_lock();
3077
3078         tun = tun_get(tfile);
3079         if (cmd == TUNSETIFF) {
3080                 ret = -EEXIST;
3081                 if (tun)
3082                         goto unlock;
3083
3084                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3085
3086                 ret = tun_set_iff(net, file, &ifr);
3087
3088                 if (ret)
3089                         goto unlock;
3090
3091                 if (copy_to_user(argp, &ifr, ifreq_len))
3092                         ret = -EFAULT;
3093                 goto unlock;
3094         }
3095         if (cmd == TUNSETIFINDEX) {
3096                 ret = -EPERM;
3097                 if (tun)
3098                         goto unlock;
3099
3100                 ret = -EFAULT;
3101                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3102                         goto unlock;
3103
3104                 ret = 0;
3105                 tfile->ifindex = ifindex;
3106                 goto unlock;
3107         }
3108
3109         ret = -EBADFD;
3110         if (!tun)
3111                 goto unlock;
3112
3113         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
3114
3115         net = dev_net(tun->dev);
3116         ret = 0;
3117         switch (cmd) {
3118         case TUNGETIFF:
3119                 tun_get_iff(tun, &ifr);
3120
3121                 if (tfile->detached)
3122                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
3123                 if (!tfile->socket.sk->sk_filter)
3124                         ifr.ifr_flags |= IFF_NOFILTER;
3125
3126                 if (copy_to_user(argp, &ifr, ifreq_len))
3127                         ret = -EFAULT;
3128                 break;
3129
3130         case TUNSETNOCSUM:
3131                 /* Disable/Enable checksum */
3132
3133                 /* [unimplemented] */
3134                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
3135                           arg ? "disabled" : "enabled");
3136                 break;
3137
3138         case TUNSETPERSIST:
3139                 /* Disable/Enable persist mode. Keep an extra reference to the
3140                  * module to prevent the module being unprobed.
3141                  */
3142                 if (arg && !(tun->flags & IFF_PERSIST)) {
3143                         tun->flags |= IFF_PERSIST;
3144                         __module_get(THIS_MODULE);
3145                         do_notify = true;
3146                 }
3147                 if (!arg && (tun->flags & IFF_PERSIST)) {
3148                         tun->flags &= ~IFF_PERSIST;
3149                         module_put(THIS_MODULE);
3150                         do_notify = true;
3151                 }
3152
3153                 tun_debug(KERN_INFO, tun, "persist %s\n",
3154                           arg ? "enabled" : "disabled");
3155                 break;
3156
3157         case TUNSETOWNER:
3158                 /* Set owner of the device */
3159                 owner = make_kuid(current_user_ns(), arg);
3160                 if (!uid_valid(owner)) {
3161                         ret = -EINVAL;
3162                         break;
3163                 }
3164                 tun->owner = owner;
3165                 do_notify = true;
3166                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
3167                           from_kuid(&init_user_ns, tun->owner));
3168                 break;
3169
3170         case TUNSETGROUP:
3171                 /* Set group of the device */
3172                 group = make_kgid(current_user_ns(), arg);
3173                 if (!gid_valid(group)) {
3174                         ret = -EINVAL;
3175                         break;
3176                 }
3177                 tun->group = group;
3178                 do_notify = true;
3179                 tun_debug(KERN_INFO, tun, "group set to %u\n",
3180                           from_kgid(&init_user_ns, tun->group));
3181                 break;
3182
3183         case TUNSETLINK:
3184                 /* Only allow setting the type when the interface is down */
3185                 if (tun->dev->flags & IFF_UP) {
3186                         tun_debug(KERN_INFO, tun,
3187                                   "Linktype set failed because interface is up\n");
3188                         ret = -EBUSY;
3189                 } else {
3190                         tun->dev->type = (int) arg;
3191                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
3192                                   tun->dev->type);
3193                         ret = 0;
3194                 }
3195                 break;
3196
3197 #ifdef TUN_DEBUG
3198         case TUNSETDEBUG:
3199                 tun->debug = arg;
3200                 break;
3201 #endif
3202         case TUNSETOFFLOAD:
3203                 ret = set_offload(tun, arg);
3204                 break;
3205
3206         case TUNSETTXFILTER:
3207                 /* Can be set only for TAPs */
3208                 ret = -EINVAL;
3209                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3210                         break;
3211                 ret = update_filter(&tun->txflt, (void __user *)arg);
3212                 break;
3213
3214         case SIOCGIFHWADDR:
3215                 /* Get hw address */
3216                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3217                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3218                 if (copy_to_user(argp, &ifr, ifreq_len))
3219                         ret = -EFAULT;
3220                 break;
3221
3222         case SIOCSIFHWADDR:
3223                 /* Set hw address */
3224                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
3225                           ifr.ifr_hwaddr.sa_data);
3226
3227                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr, NULL);
3228                 break;
3229
3230         case TUNGETSNDBUF:
3231                 sndbuf = tfile->socket.sk->sk_sndbuf;
3232                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3233                         ret = -EFAULT;
3234                 break;
3235
3236         case TUNSETSNDBUF:
3237                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3238                         ret = -EFAULT;
3239                         break;
3240                 }
3241                 if (sndbuf <= 0) {
3242                         ret = -EINVAL;
3243                         break;
3244                 }
3245
3246                 tun->sndbuf = sndbuf;
3247                 tun_set_sndbuf(tun);
3248                 break;
3249
3250         case TUNGETVNETHDRSZ:
3251                 vnet_hdr_sz = tun->vnet_hdr_sz;
3252                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3253                         ret = -EFAULT;
3254                 break;
3255
3256         case TUNSETVNETHDRSZ:
3257                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3258                         ret = -EFAULT;
3259                         break;
3260                 }
3261                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3262                         ret = -EINVAL;
3263                         break;
3264                 }
3265
3266                 tun->vnet_hdr_sz = vnet_hdr_sz;
3267                 break;
3268
3269         case TUNGETVNETLE:
3270                 le = !!(tun->flags & TUN_VNET_LE);
3271                 if (put_user(le, (int __user *)argp))
3272                         ret = -EFAULT;
3273                 break;
3274
3275         case TUNSETVNETLE:
3276                 if (get_user(le, (int __user *)argp)) {
3277                         ret = -EFAULT;
3278                         break;
3279                 }
3280                 if (le)
3281                         tun->flags |= TUN_VNET_LE;
3282                 else
3283                         tun->flags &= ~TUN_VNET_LE;
3284                 break;
3285
3286         case TUNGETVNETBE:
3287                 ret = tun_get_vnet_be(tun, argp);
3288                 break;
3289
3290         case TUNSETVNETBE:
3291                 ret = tun_set_vnet_be(tun, argp);
3292                 break;
3293
3294         case TUNATTACHFILTER:
3295                 /* Can be set only for TAPs */
3296                 ret = -EINVAL;
3297                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3298                         break;
3299                 ret = -EFAULT;
3300                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3301                         break;
3302
3303                 ret = tun_attach_filter(tun);
3304                 break;
3305
3306         case TUNDETACHFILTER:
3307                 /* Can be set only for TAPs */
3308                 ret = -EINVAL;
3309                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3310                         break;
3311                 ret = 0;
3312                 tun_detach_filter(tun, tun->numqueues);
3313                 break;
3314
3315         case TUNGETFILTER:
3316                 ret = -EINVAL;
3317                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3318                         break;
3319                 ret = -EFAULT;
3320                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3321                         break;
3322                 ret = 0;
3323                 break;
3324
3325         case TUNSETSTEERINGEBPF:
3326                 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3327                 break;
3328
3329         case TUNSETFILTEREBPF:
3330                 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3331                 break;
3332
3333         case TUNSETCARRIER:
3334                 ret = -EFAULT;
3335                 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3336                         goto unlock;
3337
3338                 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3339                 break;
3340
3341         case TUNGETDEVNETNS:
3342                 ret = -EPERM;
3343                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3344                         goto unlock;
3345                 ret = open_related_ns(&net->ns, get_net_ns);
3346                 break;
3347
3348         default:
3349                 ret = -EINVAL;
3350                 break;
3351         }
3352
3353         if (do_notify)
3354                 netdev_state_change(tun->dev);
3355
3356 unlock:
3357         rtnl_unlock();
3358         if (tun)
3359                 tun_put(tun);
3360         return ret;
3361 }
3362
3363 static long tun_chr_ioctl(struct file *file,
3364                           unsigned int cmd, unsigned long arg)
3365 {
3366         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3367 }
3368
3369 #ifdef CONFIG_COMPAT
3370 static long tun_chr_compat_ioctl(struct file *file,
3371                          unsigned int cmd, unsigned long arg)
3372 {
3373         switch (cmd) {
3374         case TUNSETIFF:
3375         case TUNGETIFF:
3376         case TUNSETTXFILTER:
3377         case TUNGETSNDBUF:
3378         case TUNSETSNDBUF:
3379         case SIOCGIFHWADDR:
3380         case SIOCSIFHWADDR:
3381                 arg = (unsigned long)compat_ptr(arg);
3382                 break;
3383         default:
3384                 arg = (compat_ulong_t)arg;
3385                 break;
3386         }
3387
3388         /*
3389          * compat_ifreq is shorter than ifreq, so we must not access beyond
3390          * the end of that structure. All fields that are used in this
3391          * driver are compatible though, we don't need to convert the
3392          * contents.
3393          */
3394         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3395 }
3396 #endif /* CONFIG_COMPAT */
3397
3398 static int tun_chr_fasync(int fd, struct file *file, int on)
3399 {
3400         struct tun_file *tfile = file->private_data;
3401         int ret;
3402
3403         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3404                 goto out;
3405
3406         if (on) {
3407                 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3408                 tfile->flags |= TUN_FASYNC;
3409         } else
3410                 tfile->flags &= ~TUN_FASYNC;
3411         ret = 0;
3412 out:
3413         return ret;
3414 }
3415
3416 static int tun_chr_open(struct inode *inode, struct file * file)
3417 {
3418         struct net *net = current->nsproxy->net_ns;
3419         struct tun_file *tfile;
3420
3421         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
3422
3423         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3424                                             &tun_proto, 0);
3425         if (!tfile)
3426                 return -ENOMEM;
3427         if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3428                 sk_free(&tfile->sk);
3429                 return -ENOMEM;
3430         }
3431
3432         mutex_init(&tfile->napi_mutex);
3433         RCU_INIT_POINTER(tfile->tun, NULL);
3434         tfile->flags = 0;
3435         tfile->ifindex = 0;
3436
3437         init_waitqueue_head(&tfile->socket.wq.wait);
3438
3439         tfile->socket.file = file;
3440         tfile->socket.ops = &tun_socket_ops;
3441
3442         sock_init_data(&tfile->socket, &tfile->sk);
3443
3444         tfile->sk.sk_write_space = tun_sock_write_space;
3445         tfile->sk.sk_sndbuf = INT_MAX;
3446
3447         file->private_data = tfile;
3448         INIT_LIST_HEAD(&tfile->next);
3449
3450         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3451
3452         return 0;
3453 }
3454
3455 static int tun_chr_close(struct inode *inode, struct file *file)
3456 {
3457         struct tun_file *tfile = file->private_data;
3458
3459         tun_detach(tfile, true);
3460
3461         return 0;
3462 }
3463
3464 #ifdef CONFIG_PROC_FS
3465 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3466 {
3467         struct tun_file *tfile = file->private_data;
3468         struct tun_struct *tun;
3469         struct ifreq ifr;
3470
3471         memset(&ifr, 0, sizeof(ifr));
3472
3473         rtnl_lock();
3474         tun = tun_get(tfile);
3475         if (tun)
3476                 tun_get_iff(tun, &ifr);
3477         rtnl_unlock();
3478
3479         if (tun)
3480                 tun_put(tun);
3481
3482         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3483 }
3484 #endif
3485
3486 static const struct file_operations tun_fops = {
3487         .owner  = THIS_MODULE,
3488         .llseek = no_llseek,
3489         .read_iter  = tun_chr_read_iter,
3490         .write_iter = tun_chr_write_iter,
3491         .poll   = tun_chr_poll,
3492         .unlocked_ioctl = tun_chr_ioctl,
3493 #ifdef CONFIG_COMPAT
3494         .compat_ioctl = tun_chr_compat_ioctl,
3495 #endif
3496         .open   = tun_chr_open,
3497         .release = tun_chr_close,
3498         .fasync = tun_chr_fasync,
3499 #ifdef CONFIG_PROC_FS
3500         .show_fdinfo = tun_chr_show_fdinfo,
3501 #endif
3502 };
3503
3504 static struct miscdevice tun_miscdev = {
3505         .minor = TUN_MINOR,
3506         .name = "tun",
3507         .nodename = "net/tun",
3508         .fops = &tun_fops,
3509 };
3510
3511 /* ethtool interface */
3512
3513 static void tun_default_link_ksettings(struct net_device *dev,
3514                                        struct ethtool_link_ksettings *cmd)
3515 {
3516         ethtool_link_ksettings_zero_link_mode(cmd, supported);
3517         ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3518         cmd->base.speed         = SPEED_10;
3519         cmd->base.duplex        = DUPLEX_FULL;
3520         cmd->base.port          = PORT_TP;
3521         cmd->base.phy_address   = 0;
3522         cmd->base.autoneg       = AUTONEG_DISABLE;
3523 }
3524
3525 static int tun_get_link_ksettings(struct net_device *dev,
3526                                   struct ethtool_link_ksettings *cmd)
3527 {
3528         struct tun_struct *tun = netdev_priv(dev);
3529
3530         memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3531         return 0;
3532 }
3533
3534 static int tun_set_link_ksettings(struct net_device *dev,
3535                                   const struct ethtool_link_ksettings *cmd)
3536 {
3537         struct tun_struct *tun = netdev_priv(dev);
3538
3539         memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3540         return 0;
3541 }
3542
3543 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3544 {
3545         struct tun_struct *tun = netdev_priv(dev);
3546
3547         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3548         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3549
3550         switch (tun->flags & TUN_TYPE_MASK) {
3551         case IFF_TUN:
3552                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3553                 break;
3554         case IFF_TAP:
3555                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3556                 break;
3557         }
3558 }
3559
3560 static u32 tun_get_msglevel(struct net_device *dev)
3561 {
3562 #ifdef TUN_DEBUG
3563         struct tun_struct *tun = netdev_priv(dev);
3564         return tun->debug;
3565 #else
3566         return -EOPNOTSUPP;
3567 #endif
3568 }
3569
3570 static void tun_set_msglevel(struct net_device *dev, u32 value)
3571 {
3572 #ifdef TUN_DEBUG
3573         struct tun_struct *tun = netdev_priv(dev);
3574         tun->debug = value;
3575 #endif
3576 }
3577
3578 static int tun_get_coalesce(struct net_device *dev,
3579                             struct ethtool_coalesce *ec)
3580 {
3581         struct tun_struct *tun = netdev_priv(dev);
3582
3583         ec->rx_max_coalesced_frames = tun->rx_batched;
3584
3585         return 0;
3586 }
3587
3588 static int tun_set_coalesce(struct net_device *dev,
3589                             struct ethtool_coalesce *ec)
3590 {
3591         struct tun_struct *tun = netdev_priv(dev);
3592
3593         if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3594                 tun->rx_batched = NAPI_POLL_WEIGHT;
3595         else
3596                 tun->rx_batched = ec->rx_max_coalesced_frames;
3597
3598         return 0;
3599 }
3600
3601 static const struct ethtool_ops tun_ethtool_ops = {
3602         .get_drvinfo    = tun_get_drvinfo,
3603         .get_msglevel   = tun_get_msglevel,
3604         .set_msglevel   = tun_set_msglevel,
3605         .get_link       = ethtool_op_get_link,
3606         .get_ts_info    = ethtool_op_get_ts_info,
3607         .get_coalesce   = tun_get_coalesce,
3608         .set_coalesce   = tun_set_coalesce,
3609         .get_link_ksettings = tun_get_link_ksettings,
3610         .set_link_ksettings = tun_set_link_ksettings,
3611 };
3612
3613 static int tun_queue_resize(struct tun_struct *tun)
3614 {
3615         struct net_device *dev = tun->dev;
3616         struct tun_file *tfile;
3617         struct ptr_ring **rings;
3618         int n = tun->numqueues + tun->numdisabled;
3619         int ret, i;
3620
3621         rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3622         if (!rings)
3623                 return -ENOMEM;
3624
3625         for (i = 0; i < tun->numqueues; i++) {
3626                 tfile = rtnl_dereference(tun->tfiles[i]);
3627                 rings[i] = &tfile->tx_ring;
3628         }
3629         list_for_each_entry(tfile, &tun->disabled, next)
3630                 rings[i++] = &tfile->tx_ring;
3631
3632         ret = ptr_ring_resize_multiple(rings, n,
3633                                        dev->tx_queue_len, GFP_KERNEL,
3634                                        tun_ptr_free);
3635
3636         kfree(rings);
3637         return ret;
3638 }
3639
3640 static int tun_device_event(struct notifier_block *unused,
3641                             unsigned long event, void *ptr)
3642 {
3643         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3644         struct tun_struct *tun = netdev_priv(dev);
3645         int i;
3646
3647         if (dev->rtnl_link_ops != &tun_link_ops)
3648                 return NOTIFY_DONE;
3649
3650         switch (event) {
3651         case NETDEV_CHANGE_TX_QUEUE_LEN:
3652                 if (tun_queue_resize(tun))
3653                         return NOTIFY_BAD;
3654                 break;
3655         case NETDEV_UP:
3656                 for (i = 0; i < tun->numqueues; i++) {
3657                         struct tun_file *tfile;
3658
3659                         tfile = rtnl_dereference(tun->tfiles[i]);
3660                         tfile->socket.sk->sk_write_space(tfile->socket.sk);
3661                 }
3662                 break;
3663         default:
3664                 break;
3665         }
3666
3667         return NOTIFY_DONE;
3668 }
3669
3670 static struct notifier_block tun_notifier_block __read_mostly = {
3671         .notifier_call  = tun_device_event,
3672 };
3673
3674 static int __init tun_init(void)
3675 {
3676         int ret = 0;
3677
3678         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3679
3680         ret = rtnl_link_register(&tun_link_ops);
3681         if (ret) {
3682                 pr_err("Can't register link_ops\n");
3683                 goto err_linkops;
3684         }
3685
3686         ret = misc_register(&tun_miscdev);
3687         if (ret) {
3688                 pr_err("Can't register misc device %d\n", TUN_MINOR);
3689                 goto err_misc;
3690         }
3691
3692         ret = register_netdevice_notifier(&tun_notifier_block);
3693         if (ret) {
3694                 pr_err("Can't register netdevice notifier\n");
3695                 goto err_notifier;
3696         }
3697
3698         return  0;
3699
3700 err_notifier:
3701         misc_deregister(&tun_miscdev);
3702 err_misc:
3703         rtnl_link_unregister(&tun_link_ops);
3704 err_linkops:
3705         return ret;
3706 }
3707
3708 static void tun_cleanup(void)
3709 {
3710         misc_deregister(&tun_miscdev);
3711         rtnl_link_unregister(&tun_link_ops);
3712         unregister_netdevice_notifier(&tun_notifier_block);
3713 }
3714
3715 /* Get an underlying socket object from tun file.  Returns error unless file is
3716  * attached to a device.  The returned object works like a packet socket, it
3717  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
3718  * holding a reference to the file for as long as the socket is in use. */
3719 struct socket *tun_get_socket(struct file *file)
3720 {
3721         struct tun_file *tfile;
3722         if (file->f_op != &tun_fops)
3723                 return ERR_PTR(-EINVAL);
3724         tfile = file->private_data;
3725         if (!tfile)
3726                 return ERR_PTR(-EBADFD);
3727         return &tfile->socket;
3728 }
3729 EXPORT_SYMBOL_GPL(tun_get_socket);
3730
3731 struct ptr_ring *tun_get_tx_ring(struct file *file)
3732 {
3733         struct tun_file *tfile;
3734
3735         if (file->f_op != &tun_fops)
3736                 return ERR_PTR(-EINVAL);
3737         tfile = file->private_data;
3738         if (!tfile)
3739                 return ERR_PTR(-EBADFD);
3740         return &tfile->tx_ring;
3741 }
3742 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3743
3744 module_init(tun_init);
3745 module_exit(tun_cleanup);
3746 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3747 MODULE_AUTHOR(DRV_COPYRIGHT);
3748 MODULE_LICENSE("GPL");
3749 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3750 MODULE_ALIAS("devname:net/tun");