drivers/net/tun.c

   1 /*
   2  *  TUN - Universal TUN/TAP device driver.
   3  *  Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
  16  */
  17
  18 /*
  19  *  Changes:
  20  *
  21  *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
  22  *    Add TUNSETLINK ioctl to set the link encapsulation
  23  *
  24  *  Mark Smith <markzzzsmith@yahoo.com.au>
  25  *    Use eth_random_addr() for tap MAC address.
  26  *
  27  *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
  28  *    Fixes in packet dropping, queue length setting and queue wakeup.
  29  *    Increased default tx queue length.
  30  *    Added ethtool API.
  31  *    Minor cleanups
  32  *
  33  *  Daniel Podlejski <underley@underley.eu.org>
  34  *    Modifications for 2.3.99-pre5 kernel.
  35  */
  36
  37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  38
  39 #define DRV_NAME        "tun"
  40 #define DRV_VERSION     "1.6"
  41 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  42 #define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
  43
  44 #include <linux/module.h>
  45 #include <linux/errno.h>
  46 #include <linux/kernel.h>
  47 #include <linux/sched/signal.h>
  48 #include <linux/major.h>
  49 #include <linux/slab.h>
  50 #include <linux/poll.h>
  51 #include <linux/fcntl.h>
  52 #include <linux/init.h>
  53 #include <linux/skbuff.h>
  54 #include <linux/netdevice.h>
  55 #include <linux/etherdevice.h>
  56 #include <linux/miscdevice.h>
  57 #include <linux/ethtool.h>
  58 #include <linux/rtnetlink.h>
  59 #include <linux/compat.h>
  60 #include <linux/if.h>
  61 #include <linux/if_arp.h>
  62 #include <linux/if_ether.h>
  63 #include <linux/if_tun.h>
  64 #include <linux/if_vlan.h>
  65 #include <linux/crc32.h>
  66 #include <linux/nsproxy.h>
  67 #include <linux/virtio_net.h>
  68 #include <linux/rcupdate.h>
  69 #include <net/net_namespace.h>
  70 #include <net/netns/generic.h>
  71 #include <net/rtnetlink.h>
  72 #include <net/sock.h>
  73 #include <net/xdp.h>
  74 #include <linux/seq_file.h>
  75 #include <linux/uio.h>
  76 #include <linux/skb_array.h>
  77 #include <linux/bpf.h>
  78 #include <linux/bpf_trace.h>
  79 #include <linux/mutex.h>
  80
  81 #include <linux/uaccess.h>
  82 #include <linux/proc_fs.h>
  83
  84 /* Uncomment to enable debugging */
  85 /* #define TUN_DEBUG 1 */
  86
  87 #ifdef TUN_DEBUG
  88 static int debug;
  89
  90 #define tun_debug(level, tun, fmt, args...)                     \
  91 do {                                                            \
  92         if (tun->debug)                                         \
  93                 netdev_printk(level, tun->dev, fmt, ##args);    \
  94 } while (0)
  95 #define DBG1(level, fmt, args...)                               \
  96 do {                                                            \
  97         if (debug == 2)                                         \
  98                 printk(level fmt, ##args);                      \
  99 } while (0)
 100 #else
 101 #define tun_debug(level, tun, fmt, args...)                     \
 102 do {                                                            \
 103         if (0)                                                  \
 104                 netdev_printk(level, tun->dev, fmt, ##args);    \
 105 } while (0)
 106 #define DBG1(level, fmt, args...)                               \
 107 do {                                                            \
 108         if (0)                                                  \
 109                 printk(level fmt, ##args);                      \
 110 } while (0)
 111 #endif
 112
 113 #define TUN_HEADROOM 256
 114 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
 115
 116 /* TUN device flags */
 117
 118 /* IFF_ATTACH_QUEUE is never stored in device flags,
 119  * overload it to mean fasync when stored there.
 120  */
 121 #define TUN_FASYNC      IFF_ATTACH_QUEUE
 122 /* High bits in flags field are unused. */
 123 #define TUN_VNET_LE     0x80000000
 124 #define TUN_VNET_BE     0x40000000
 125
 126 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
 127                       IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
 128
 129 #define GOODCOPY_LEN 128
 130
 131 #define FLT_EXACT_COUNT 8
 132 struct tap_filter {
 133         unsigned int    count;    /* Number of addrs. Zero means disabled */
 134         u32             mask[2];  /* Mask of the hashed addrs */
 135         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 136 };
 137
 138 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
 139  * to max number of VCPUs in guest. */
 140 #define MAX_TAP_QUEUES 256
 141 #define MAX_TAP_FLOWS  4096
 142
 143 #define TUN_FLOW_EXPIRE (3 * HZ)
 144
 145 struct tun_pcpu_stats {
 146         u64 rx_packets;
 147         u64 rx_bytes;
 148         u64 tx_packets;
 149         u64 tx_bytes;
 150         struct u64_stats_sync syncp;
 151         u32 rx_dropped;
 152         u32 tx_dropped;
 153         u32 rx_frame_errors;
 154 };
 155
 156 /* A tun_file connects an open character device to a tuntap netdevice. It
 157  * also contains all socket related structures (except sock_fprog and tap_filter)
 158  * to serve as one transmit queue for tuntap device. The sock_fprog and
 159  * tap_filter were kept in tun_struct since they were used for filtering for the
 160  * netdevice not for a specific queue (at least I didn't see the requirement for
 161  * this).
 162  *
 163  * RCU usage:
 164  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
 165  * other can only be read while rcu_read_lock or rtnl_lock is held.
 166  */
 167 struct tun_file {
 168         struct sock sk;
 169         struct socket socket;
 170         struct socket_wq wq;
 171         struct tun_struct __rcu *tun;
 172         struct fasync_struct *fasync;
 173         /* only used for fasnyc */
 174         unsigned int flags;
 175         union {
 176                 u16 queue_index;
 177                 unsigned int ifindex;
 178         };
 179         struct napi_struct napi;
 180         bool napi_enabled;
 181         struct mutex napi_mutex;        /* Protects access to the above napi */
 182         struct list_head next;
 183         struct tun_struct *detached;
 184         struct ptr_ring tx_ring;
 185         struct xdp_rxq_info xdp_rxq;
 186 };
 187
 188 struct tun_flow_entry {
 189         struct hlist_node hash_link;
 190         struct rcu_head rcu;
 191         struct tun_struct *tun;
 192
 193         u32 rxhash;
 194         u32 rps_rxhash;
 195         int queue_index;
 196         unsigned long updated;
 197 };
 198
 199 #define TUN_NUM_FLOW_ENTRIES 1024
 200
 201 struct tun_prog {
 202         struct rcu_head rcu;
 203         struct bpf_prog *prog;
 204 };
 205
 206 /* Since the socket were moved to tun_file, to preserve the behavior of persist
 207  * device, socket filter, sndbuf and vnet header size were restore when the
 208  * file were attached to a persist device.
 209  */
 210 struct tun_struct {
 211         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
 212         unsigned int            numqueues;
 213         unsigned int            flags;
 214         kuid_t                  owner;
 215         kgid_t                  group;
 216
 217         struct net_device       *dev;
 218         netdev_features_t       set_features;
 219 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 220                           NETIF_F_TSO6)
 221
 222         int                     align;
 223         int                     vnet_hdr_sz;
 224         int                     sndbuf;
 225         struct tap_filter       txflt;
 226         struct sock_fprog       fprog;
 227         /* protected by rtnl lock */
 228         bool                    filter_attached;
 229 #ifdef TUN_DEBUG
 230         int debug;
 231 #endif
 232         spinlock_t lock;
 233         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 234         struct timer_list flow_gc_timer;
 235         unsigned long ageing_time;
 236         unsigned int numdisabled;
 237         struct list_head disabled;
 238         void *security;
 239         u32 flow_count;
 240         u32 rx_batched;
 241         struct tun_pcpu_stats __percpu *pcpu_stats;
 242         struct bpf_prog __rcu *xdp_prog;
 243         struct tun_prog __rcu *steering_prog;
 244         struct tun_prog __rcu *filter_prog;
 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)
 312 {
 313         tfile->napi_enabled = napi_en;
 314         if (napi_en) {
 315                 netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
 316                                NAPI_POLL_WEIGHT);
 317                 napi_enable(&tfile->napi);
 318                 mutex_init(&tfile->napi_mutex);
 319         }
 320 }
 321
 322 static void tun_napi_disable(struct tun_struct *tun, 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_struct *tun, 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_struct *tun)
 335 {
 336         return READ_ONCE(tun->flags) & IFF_NAPI_FRAGS;
 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 & 0x3ff;
 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         if (!rxhash)
 523                 return;
 524         else
 525                 head = &tun->flows[tun_hashfn(rxhash)];
 526
 527         rcu_read_lock();
 528
 529         e = tun_flow_find(head, rxhash);
 530         if (likely(e)) {
 531                 /* TODO: keep queueing to old queue until it's empty? */
 532                 e->queue_index = queue_index;
 533                 e->updated = jiffies;
 534                 sock_rps_record_flow_hash(e->rps_rxhash);
 535         } else {
 536                 spin_lock_bh(&tun->lock);
 537                 if (!tun_flow_find(head, rxhash) &&
 538                     tun->flow_count < MAX_TAP_FLOWS)
 539                         tun_flow_create(tun, head, rxhash, queue_index);
 540
 541                 if (!timer_pending(&tun->flow_gc_timer))
 542                         mod_timer(&tun->flow_gc_timer,
 543                                   round_jiffies_up(jiffies + delay));
 544                 spin_unlock_bh(&tun->lock);
 545         }
 546
 547         rcu_read_unlock();
 548 }
 549
 550 /**
 551  * Save the hash received in the stack receive path and update the
 552  * flow_hash table accordingly.
 553  */
 554 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
 555 {
 556         if (unlikely(e->rps_rxhash != hash))
 557                 e->rps_rxhash = hash;
 558 }
 559
 560 /* We try to identify a flow through its rxhash first. The reason that
 561  * we do not check rxq no. is because some cards(e.g 82599), chooses
 562  * the rxq based on the txq where the last packet of the flow comes. As
 563  * the userspace application move between processors, we may get a
 564  * different rxq no. here. If we could not get rxhash, then we would
 565  * hope the rxq no. may help here.
 566  */
 567 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 568 {
 569         struct tun_flow_entry *e;
 570         u32 txq = 0;
 571         u32 numqueues = 0;
 572
 573         numqueues = READ_ONCE(tun->numqueues);
 574
 575         txq = __skb_get_hash_symmetric(skb);
 576         if (txq) {
 577                 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 578                 if (e) {
 579                         tun_flow_save_rps_rxhash(e, txq);
 580                         txq = e->queue_index;
 581                 } else
 582                         /* use multiply and shift instead of expensive divide */
 583                         txq = ((u64)txq * numqueues) >> 32;
 584         } else if (likely(skb_rx_queue_recorded(skb))) {
 585                 txq = skb_get_rx_queue(skb);
 586                 while (unlikely(txq >= numqueues))
 587                         txq -= numqueues;
 588         }
 589
 590         return txq;
 591 }
 592
 593 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 594 {
 595         struct tun_prog *prog;
 596         u16 ret = 0;
 597
 598         prog = rcu_dereference(tun->steering_prog);
 599         if (prog)
 600                 ret = bpf_prog_run_clear_cb(prog->prog, skb);
 601
 602         return ret % tun->numqueues;
 603 }
 604
 605 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
 606                             void *accel_priv, select_queue_fallback_t fallback)
 607 {
 608         struct tun_struct *tun = netdev_priv(dev);
 609         u16 ret;
 610
 611         rcu_read_lock();
 612         if (rcu_dereference(tun->steering_prog))
 613                 ret = tun_ebpf_select_queue(tun, skb);
 614         else
 615                 ret = tun_automq_select_queue(tun, skb);
 616         rcu_read_unlock();
 617
 618         return ret;
 619 }
 620
 621 static inline bool tun_not_capable(struct tun_struct *tun)
 622 {
 623         const struct cred *cred = current_cred();
 624         struct net *net = dev_net(tun->dev);
 625
 626         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 627                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 628                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 629 }
 630
 631 static void tun_set_real_num_queues(struct tun_struct *tun)
 632 {
 633         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 634         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 635 }
 636
 637 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 638 {
 639         tfile->detached = tun;
 640         list_add_tail(&tfile->next, &tun->disabled);
 641         ++tun->numdisabled;
 642 }
 643
 644 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 645 {
 646         struct tun_struct *tun = tfile->detached;
 647
 648         tfile->detached = NULL;
 649         list_del_init(&tfile->next);
 650         --tun->numdisabled;
 651         return tun;
 652 }
 653
 654 void tun_ptr_free(void *ptr)
 655 {
 656         if (!ptr)
 657                 return;
 658         if (tun_is_xdp_frame(ptr)) {
 659                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
 660
 661                 xdp_return_frame(xdpf);
 662         } else {
 663                 __skb_array_destroy_skb(ptr);
 664         }
 665 }
 666 EXPORT_SYMBOL_GPL(tun_ptr_free);
 667
 668 static void tun_queue_purge(struct tun_file *tfile)
 669 {
 670         void *ptr;
 671
 672         while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
 673                 tun_ptr_free(ptr);
 674
 675         skb_queue_purge(&tfile->sk.sk_write_queue);
 676         skb_queue_purge(&tfile->sk.sk_error_queue);
 677 }
 678
 679 static void __tun_detach(struct tun_file *tfile, bool clean)
 680 {
 681         struct tun_file *ntfile;
 682         struct tun_struct *tun;
 683
 684         tun = rtnl_dereference(tfile->tun);
 685
 686         if (tun && clean) {
 687                 tun_napi_disable(tun, tfile);
 688                 tun_napi_del(tun, tfile);
 689         }
 690
 691         if (tun && !tfile->detached) {
 692                 u16 index = tfile->queue_index;
 693                 BUG_ON(index >= tun->numqueues);
 694
 695                 rcu_assign_pointer(tun->tfiles[index],
 696                                    tun->tfiles[tun->numqueues - 1]);
 697                 ntfile = rtnl_dereference(tun->tfiles[index]);
 698                 ntfile->queue_index = index;
 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(tun, 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(tun, 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)
 791 {
 792         struct tun_file *tfile = file->private_data;
 793         struct net_device *dev = tun->dev;
 794         int err;
 795
 796         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 797         if (err < 0)
 798                 goto out;
 799
 800         err = -EINVAL;
 801         if (rtnl_dereference(tfile->tun) && !tfile->detached)
 802                 goto out;
 803
 804         err = -EBUSY;
 805         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
 806                 goto out;
 807
 808         err = -E2BIG;
 809         if (!tfile->detached &&
 810             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 811                 goto out;
 812
 813         err = 0;
 814
 815         /* Re-attach the filter to persist device */
 816         if (!skip_filter && (tun->filter_attached == true)) {
 817                 lock_sock(tfile->socket.sk);
 818                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 819                 release_sock(tfile->socket.sk);
 820                 if (!err)
 821                         goto out;
 822         }
 823
 824         if (!tfile->detached &&
 825             ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
 826                             GFP_KERNEL, tun_ptr_free)) {
 827                 err = -ENOMEM;
 828                 goto out;
 829         }
 830
 831         tfile->queue_index = tun->numqueues;
 832         tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
 833
 834         if (tfile->detached) {
 835                 /* Re-attach detached tfile, updating XDP queue_index */
 836                 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
 837
 838                 if (tfile->xdp_rxq.queue_index    != tfile->queue_index)
 839                         tfile->xdp_rxq.queue_index = tfile->queue_index;
 840         } else {
 841                 /* Setup XDP RX-queue info, for new tfile getting attached */
 842                 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
 843                                        tun->dev, tfile->queue_index);
 844                 if (err < 0)
 845                         goto out;
 846                 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
 847                                                  MEM_TYPE_PAGE_SHARED, NULL);
 848                 if (err < 0) {
 849                         xdp_rxq_info_unreg(&tfile->xdp_rxq);
 850                         goto out;
 851                 }
 852                 err = 0;
 853         }
 854
 855         rcu_assign_pointer(tfile->tun, tun);
 856         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 857         tun->numqueues++;
 858
 859         if (tfile->detached) {
 860                 tun_enable_queue(tfile);
 861         } else {
 862                 sock_hold(&tfile->sk);
 863                 tun_napi_init(tun, tfile, napi);
 864         }
 865
 866         tun_set_real_num_queues(tun);
 867
 868         /* device is allowed to go away first, so no need to hold extra
 869          * refcnt.
 870          */
 871
 872 out:
 873         return err;
 874 }
 875
 876 static struct tun_struct *tun_get(struct tun_file *tfile)
 877 {
 878         struct tun_struct *tun;
 879
 880         rcu_read_lock();
 881         tun = rcu_dereference(tfile->tun);
 882         if (tun)
 883                 dev_hold(tun->dev);
 884         rcu_read_unlock();
 885
 886         return tun;
 887 }
 888
 889 static void tun_put(struct tun_struct *tun)
 890 {
 891         dev_put(tun->dev);
 892 }
 893
 894 /* TAP filtering */
 895 static void addr_hash_set(u32 *mask, const u8 *addr)
 896 {
 897         int n = ether_crc(ETH_ALEN, addr) >> 26;
 898         mask[n >> 5] |= (1 << (n & 31));
 899 }
 900
 901 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 902 {
 903         int n = ether_crc(ETH_ALEN, addr) >> 26;
 904         return mask[n >> 5] & (1 << (n & 31));
 905 }
 906
 907 static int update_filter(struct tap_filter *filter, void __user *arg)
 908 {
 909         struct { u8 u[ETH_ALEN]; } *addr;
 910         struct tun_filter uf;
 911         int err, alen, n, nexact;
 912
 913         if (copy_from_user(&uf, arg, sizeof(uf)))
 914                 return -EFAULT;
 915
 916         if (!uf.count) {
 917                 /* Disabled */
 918                 filter->count = 0;
 919                 return 0;
 920         }
 921
 922         alen = ETH_ALEN * uf.count;
 923         addr = memdup_user(arg + sizeof(uf), alen);
 924         if (IS_ERR(addr))
 925                 return PTR_ERR(addr);
 926
 927         /* The filter is updated without holding any locks. Which is
 928          * perfectly safe. We disable it first and in the worst
 929          * case we'll accept a few undesired packets. */
 930         filter->count = 0;
 931         wmb();
 932
 933         /* Use first set of addresses as an exact filter */
 934         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 935                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 936
 937         nexact = n;
 938
 939         /* Remaining multicast addresses are hashed,
 940          * unicast will leave the filter disabled. */
 941         memset(filter->mask, 0, sizeof(filter->mask));
 942         for (; n < uf.count; n++) {
 943                 if (!is_multicast_ether_addr(addr[n].u)) {
 944                         err = 0; /* no filter */
 945                         goto free_addr;
 946                 }
 947                 addr_hash_set(filter->mask, addr[n].u);
 948         }
 949
 950         /* For ALLMULTI just set the mask to all ones.
 951          * This overrides the mask populated above. */
 952         if ((uf.flags & TUN_FLT_ALLMULTI))
 953                 memset(filter->mask, ~0, sizeof(filter->mask));
 954
 955         /* Now enable the filter */
 956         wmb();
 957         filter->count = nexact;
 958
 959         /* Return the number of exact filters */
 960         err = nexact;
 961 free_addr:
 962         kfree(addr);
 963         return err;
 964 }
 965
 966 /* Returns: 0 - drop, !=0 - accept */
 967 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 968 {
 969         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 970          * at this point. */
 971         struct ethhdr *eh = (struct ethhdr *) skb->data;
 972         int i;
 973
 974         /* Exact match */
 975         for (i = 0; i < filter->count; i++)
 976                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 977                         return 1;
 978
 979         /* Inexact match (multicast only) */
 980         if (is_multicast_ether_addr(eh->h_dest))
 981                 return addr_hash_test(filter->mask, eh->h_dest);
 982
 983         return 0;
 984 }
 985
 986 /*
 987  * Checks whether the packet is accepted or not.
 988  * Returns: 0 - drop, !=0 - accept
 989  */
 990 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 991 {
 992         if (!filter->count)
 993                 return 1;
 994
 995         return run_filter(filter, skb);
 996 }
 997
 998 /* Network device part of the driver */
 999
1000 static const struct ethtool_ops tun_ethtool_ops;
1001
1002 /* Net device detach from fd. */
1003 static void tun_net_uninit(struct net_device *dev)
1004 {
1005         tun_detach_all(dev);
1006 }
1007
1008 /* Net device open. */
1009 static int tun_net_open(struct net_device *dev)
1010 {
1011         struct tun_struct *tun = netdev_priv(dev);
1012         int i;
1013
1014         netif_tx_start_all_queues(dev);
1015
1016         for (i = 0; i < tun->numqueues; i++) {
1017                 struct tun_file *tfile;
1018
1019                 tfile = rtnl_dereference(tun->tfiles[i]);
1020                 tfile->socket.sk->sk_write_space(tfile->socket.sk);
1021         }
1022
1023         return 0;
1024 }
1025
1026 /* Net device close. */
1027 static int tun_net_close(struct net_device *dev)
1028 {
1029         netif_tx_stop_all_queues(dev);
1030         return 0;
1031 }
1032
1033 /* Net device start xmit */
1034 static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1035 {
1036 #ifdef CONFIG_RPS
1037         if (tun->numqueues == 1 && static_key_false(&rps_needed)) {
1038                 /* Select queue was not called for the skbuff, so we extract the
1039                  * RPS hash and save it into the flow_table here.
1040                  */
1041                 __u32 rxhash;
1042
1043                 rxhash = __skb_get_hash_symmetric(skb);
1044                 if (rxhash) {
1045                         struct tun_flow_entry *e;
1046                         e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
1047                                         rxhash);
1048                         if (e)
1049                                 tun_flow_save_rps_rxhash(e, rxhash);
1050                 }
1051         }
1052 #endif
1053 }
1054
1055 static unsigned int run_ebpf_filter(struct tun_struct *tun,
1056                                     struct sk_buff *skb,
1057                                     int len)
1058 {
1059         struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1060
1061         if (prog)
1062                 len = bpf_prog_run_clear_cb(prog->prog, skb);
1063
1064         return len;
1065 }
1066
1067 /* Net device start xmit */
1068 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1069 {
1070         struct tun_struct *tun = netdev_priv(dev);
1071         int txq = skb->queue_mapping;
1072         struct tun_file *tfile;
1073         int len = skb->len;
1074
1075         rcu_read_lock();
1076         tfile = rcu_dereference(tun->tfiles[txq]);
1077
1078         /* Drop packet if interface is not attached */
1079         if (txq >= tun->numqueues)
1080                 goto drop;
1081
1082         if (!rcu_dereference(tun->steering_prog))
1083                 tun_automq_xmit(tun, skb);
1084
1085         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
1086
1087         BUG_ON(!tfile);
1088
1089         /* Drop if the filter does not like it.
1090          * This is a noop if the filter is disabled.
1091          * Filter can be enabled only for the TAP devices. */
1092         if (!check_filter(&tun->txflt, skb))
1093                 goto drop;
1094
1095         if (tfile->socket.sk->sk_filter &&
1096             sk_filter(tfile->socket.sk, skb))
1097                 goto drop;
1098
1099         len = run_ebpf_filter(tun, skb, len);
1100         if (len == 0 || pskb_trim(skb, len))
1101                 goto drop;
1102
1103         if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1104                 goto drop;
1105
1106         skb_tx_timestamp(skb);
1107
1108         /* Orphan the skb - required as we might hang on to it
1109          * for indefinite time.
1110          */
1111         skb_orphan(skb);
1112
1113         nf_reset(skb);
1114
1115         if (ptr_ring_produce(&tfile->tx_ring, skb))
1116                 goto drop;
1117
1118         /* Notify and wake up reader process */
1119         if (tfile->flags & TUN_FASYNC)
1120                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1121         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1122
1123         rcu_read_unlock();
1124         return NETDEV_TX_OK;
1125
1126 drop:
1127         this_cpu_inc(tun->pcpu_stats->tx_dropped);
1128         skb_tx_error(skb);
1129         kfree_skb(skb);
1130         rcu_read_unlock();
1131         return NET_XMIT_DROP;
1132 }
1133
1134 static void tun_net_mclist(struct net_device *dev)
1135 {
1136         /*
1137          * This callback is supposed to deal with mc filter in
1138          * _rx_ path and has nothing to do with the _tx_ path.
1139          * In rx path we always accept everything userspace gives us.
1140          */
1141 }
1142
1143 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1144         netdev_features_t features)
1145 {
1146         struct tun_struct *tun = netdev_priv(dev);
1147
1148         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1149 }
1150 #ifdef CONFIG_NET_POLL_CONTROLLER
1151 static void tun_poll_controller(struct net_device *dev)
1152 {
1153         /*
1154          * Tun only receives frames when:
1155          * 1) the char device endpoint gets data from user space
1156          * 2) the tun socket gets a sendmsg call from user space
1157          * If NAPI is not enabled, since both of those are synchronous
1158          * operations, we are guaranteed never to have pending data when we poll
1159          * for it so there is nothing to do here but return.
1160          * We need this though so netpoll recognizes us as an interface that
1161          * supports polling, which enables bridge devices in virt setups to
1162          * still use netconsole
1163          * If NAPI is enabled, however, we need to schedule polling for all
1164          * queues unless we are using napi_gro_frags(), which we call in
1165          * process context and not in NAPI context.
1166          */
1167         struct tun_struct *tun = netdev_priv(dev);
1168
1169         if (tun->flags & IFF_NAPI) {
1170                 struct tun_file *tfile;
1171                 int i;
1172
1173                 if (tun_napi_frags_enabled(tun))
1174                         return;
1175
1176                 rcu_read_lock();
1177                 for (i = 0; i < tun->numqueues; i++) {
1178                         tfile = rcu_dereference(tun->tfiles[i]);
1179                         if (tfile->napi_enabled)
1180                                 napi_schedule(&tfile->napi);
1181                 }
1182                 rcu_read_unlock();
1183         }
1184         return;
1185 }
1186 #endif
1187
1188 static void tun_set_headroom(struct net_device *dev, int new_hr)
1189 {
1190         struct tun_struct *tun = netdev_priv(dev);
1191
1192         if (new_hr < NET_SKB_PAD)
1193                 new_hr = NET_SKB_PAD;
1194
1195         tun->align = new_hr;
1196 }
1197
1198 static void
1199 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1200 {
1201         u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1202         struct tun_struct *tun = netdev_priv(dev);
1203         struct tun_pcpu_stats *p;
1204         int i;
1205
1206         for_each_possible_cpu(i) {
1207                 u64 rxpackets, rxbytes, txpackets, txbytes;
1208                 unsigned int start;
1209
1210                 p = per_cpu_ptr(tun->pcpu_stats, i);
1211                 do {
1212                         start = u64_stats_fetch_begin(&p->syncp);
1213                         rxpackets       = p->rx_packets;
1214                         rxbytes         = p->rx_bytes;
1215                         txpackets       = p->tx_packets;
1216                         txbytes         = p->tx_bytes;
1217                 } while (u64_stats_fetch_retry(&p->syncp, start));
1218
1219                 stats->rx_packets       += rxpackets;
1220                 stats->rx_bytes         += rxbytes;
1221                 stats->tx_packets       += txpackets;
1222                 stats->tx_bytes         += txbytes;
1223
1224                 /* u32 counters */
1225                 rx_dropped      += p->rx_dropped;
1226                 rx_frame_errors += p->rx_frame_errors;
1227                 tx_dropped      += p->tx_dropped;
1228         }
1229         stats->rx_dropped  = rx_dropped;
1230         stats->rx_frame_errors = rx_frame_errors;
1231         stats->tx_dropped = tx_dropped;
1232 }
1233
1234 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1235                        struct netlink_ext_ack *extack)
1236 {
1237         struct tun_struct *tun = netdev_priv(dev);
1238         struct bpf_prog *old_prog;
1239
1240         old_prog = rtnl_dereference(tun->xdp_prog);
1241         rcu_assign_pointer(tun->xdp_prog, prog);
1242         if (old_prog)
1243                 bpf_prog_put(old_prog);
1244
1245         return 0;
1246 }
1247
1248 static u32 tun_xdp_query(struct net_device *dev)
1249 {
1250         struct tun_struct *tun = netdev_priv(dev);
1251         const struct bpf_prog *xdp_prog;
1252
1253         xdp_prog = rtnl_dereference(tun->xdp_prog);
1254         if (xdp_prog)
1255                 return xdp_prog->aux->id;
1256
1257         return 0;
1258 }
1259
1260 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1261 {
1262         switch (xdp->command) {
1263         case XDP_SETUP_PROG:
1264                 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1265         case XDP_QUERY_PROG:
1266                 xdp->prog_id = tun_xdp_query(dev);
1267                 xdp->prog_attached = !!xdp->prog_id;
1268                 return 0;
1269         default:
1270                 return -EINVAL;
1271         }
1272 }
1273
1274 static const struct net_device_ops tun_netdev_ops = {
1275         .ndo_uninit             = tun_net_uninit,
1276         .ndo_open               = tun_net_open,
1277         .ndo_stop               = tun_net_close,
1278         .ndo_start_xmit         = tun_net_xmit,
1279         .ndo_fix_features       = tun_net_fix_features,
1280         .ndo_select_queue       = tun_select_queue,
1281 #ifdef CONFIG_NET_POLL_CONTROLLER
1282         .ndo_poll_controller    = tun_poll_controller,
1283 #endif
1284         .ndo_set_rx_headroom    = tun_set_headroom,
1285         .ndo_get_stats64        = tun_net_get_stats64,
1286 };
1287
1288 static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1289 {
1290         /* Notify and wake up reader process */
1291         if (tfile->flags & TUN_FASYNC)
1292                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1293         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1294 }
1295
1296 static int tun_xdp_xmit(struct net_device *dev, int n,
1297                         struct xdp_frame **frames, u32 flags)
1298 {
1299         struct tun_struct *tun = netdev_priv(dev);
1300         struct tun_file *tfile;
1301         u32 numqueues;
1302         int drops = 0;
1303         int cnt = n;
1304         int i;
1305
1306         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1307                 return -EINVAL;
1308
1309         rcu_read_lock();
1310
1311         numqueues = READ_ONCE(tun->numqueues);
1312         if (!numqueues) {
1313                 rcu_read_unlock();
1314                 return -ENXIO; /* Caller will free/return all frames */
1315         }
1316
1317         tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1318                                             numqueues]);
1319
1320         spin_lock(&tfile->tx_ring.producer_lock);
1321         for (i = 0; i < n; i++) {
1322                 struct xdp_frame *xdp = frames[i];
1323                 /* Encode the XDP flag into lowest bit for consumer to differ
1324                  * XDP buffer from sk_buff.
1325                  */
1326                 void *frame = tun_xdp_to_ptr(xdp);
1327
1328                 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1329                         this_cpu_inc(tun->pcpu_stats->tx_dropped);
1330                         xdp_return_frame_rx_napi(xdp);
1331                         drops++;
1332                 }
1333         }
1334         spin_unlock(&tfile->tx_ring.producer_lock);
1335
1336         if (flags & XDP_XMIT_FLUSH)
1337                 __tun_xdp_flush_tfile(tfile);
1338
1339         rcu_read_unlock();
1340         return cnt - drops;
1341 }
1342
1343 static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1344 {
1345         struct xdp_frame *frame = convert_to_xdp_frame(xdp);
1346
1347         if (unlikely(!frame))
1348                 return -EOVERFLOW;
1349
1350         return tun_xdp_xmit(dev, 1, &frame, 0);
1351 }
1352
1353 static void tun_xdp_flush(struct net_device *dev)
1354 {
1355         struct tun_struct *tun = netdev_priv(dev);
1356         struct tun_file *tfile;
1357         u32 numqueues;
1358
1359         rcu_read_lock();
1360
1361         numqueues = READ_ONCE(tun->numqueues);
1362         if (!numqueues)
1363                 goto out;
1364
1365         tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1366                                             numqueues]);
1367         __tun_xdp_flush_tfile(tfile);
1368 out:
1369         rcu_read_unlock();
1370 }
1371
1372 static const struct net_device_ops tap_netdev_ops = {
1373         .ndo_uninit             = tun_net_uninit,
1374         .ndo_open               = tun_net_open,
1375         .ndo_stop               = tun_net_close,
1376         .ndo_start_xmit         = tun_net_xmit,
1377         .ndo_fix_features       = tun_net_fix_features,
1378         .ndo_set_rx_mode        = tun_net_mclist,
1379         .ndo_set_mac_address    = eth_mac_addr,
1380         .ndo_validate_addr      = eth_validate_addr,
1381         .ndo_select_queue       = tun_select_queue,
1382 #ifdef CONFIG_NET_POLL_CONTROLLER
1383         .ndo_poll_controller    = tun_poll_controller,
1384 #endif
1385         .ndo_features_check     = passthru_features_check,
1386         .ndo_set_rx_headroom    = tun_set_headroom,
1387         .ndo_get_stats64        = tun_net_get_stats64,
1388         .ndo_bpf                = tun_xdp,
1389         .ndo_xdp_xmit           = tun_xdp_xmit,
1390         .ndo_xdp_flush          = tun_xdp_flush,
1391 };
1392
1393 static void tun_flow_init(struct tun_struct *tun)
1394 {
1395         int i;
1396
1397         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1398                 INIT_HLIST_HEAD(&tun->flows[i]);
1399
1400         tun->ageing_time = TUN_FLOW_EXPIRE;
1401         timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1402         mod_timer(&tun->flow_gc_timer,
1403                   round_jiffies_up(jiffies + tun->ageing_time));
1404 }
1405
1406 static void tun_flow_uninit(struct tun_struct *tun)
1407 {
1408         del_timer_sync(&tun->flow_gc_timer);
1409         tun_flow_flush(tun);
1410 }
1411
1412 #define MIN_MTU 68
1413 #define MAX_MTU 65535
1414
1415 /* Initialize net device. */
1416 static void tun_net_init(struct net_device *dev)
1417 {
1418         struct tun_struct *tun = netdev_priv(dev);
1419
1420         switch (tun->flags & TUN_TYPE_MASK) {
1421         case IFF_TUN:
1422                 dev->netdev_ops = &tun_netdev_ops;
1423
1424                 /* Point-to-Point TUN Device */
1425                 dev->hard_header_len = 0;
1426                 dev->addr_len = 0;
1427                 dev->mtu = 1500;
1428
1429                 /* Zero header length */
1430                 dev->type = ARPHRD_NONE;
1431                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1432                 break;
1433
1434         case IFF_TAP:
1435                 dev->netdev_ops = &tap_netdev_ops;
1436                 /* Ethernet TAP Device */
1437                 ether_setup(dev);
1438                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1439                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1440
1441                 eth_hw_addr_random(dev);
1442
1443                 break;
1444         }
1445
1446         dev->min_mtu = MIN_MTU;
1447         dev->max_mtu = MAX_MTU - dev->hard_header_len;
1448 }
1449
1450 static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1451 {
1452         struct sock *sk = tfile->socket.sk;
1453
1454         return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1455 }
1456
1457 /* Character device part */
1458
1459 /* Poll */
1460 static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1461 {
1462         struct tun_file *tfile = file->private_data;
1463         struct tun_struct *tun = tun_get(tfile);
1464         struct sock *sk;
1465         __poll_t mask = 0;
1466
1467         if (!tun)
1468                 return EPOLLERR;
1469
1470         sk = tfile->socket.sk;
1471
1472         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1473
1474         poll_wait(file, sk_sleep(sk), wait);
1475
1476         if (!ptr_ring_empty(&tfile->tx_ring))
1477                 mask |= EPOLLIN | EPOLLRDNORM;
1478
1479         /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1480          * guarantee EPOLLOUT to be raised by either here or
1481          * tun_sock_write_space(). Then process could get notification
1482          * after it writes to a down device and meets -EIO.
1483          */
1484         if (tun_sock_writeable(tun, tfile) ||
1485             (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1486              tun_sock_writeable(tun, tfile)))
1487                 mask |= EPOLLOUT | EPOLLWRNORM;
1488
1489         if (tun->dev->reg_state != NETREG_REGISTERED)
1490                 mask = EPOLLERR;
1491
1492         tun_put(tun);
1493         return mask;
1494 }
1495
1496 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1497                                             size_t len,
1498                                             const struct iov_iter *it)
1499 {
1500         struct sk_buff *skb;
1501         size_t linear;
1502         int err;
1503         int i;
1504
1505         if (it->nr_segs > MAX_SKB_FRAGS + 1)
1506                 return ERR_PTR(-ENOMEM);
1507
1508         local_bh_disable();
1509         skb = napi_get_frags(&tfile->napi);
1510         local_bh_enable();
1511         if (!skb)
1512                 return ERR_PTR(-ENOMEM);
1513
1514         linear = iov_iter_single_seg_count(it);
1515         err = __skb_grow(skb, linear);
1516         if (err)
1517                 goto free;
1518
1519         skb->len = len;
1520         skb->data_len = len - linear;
1521         skb->truesize += skb->data_len;
1522
1523         for (i = 1; i < it->nr_segs; i++) {
1524                 struct page_frag *pfrag = &current->task_frag;
1525                 size_t fragsz = it->iov[i].iov_len;
1526
1527                 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1528                         err = -EINVAL;
1529                         goto free;
1530                 }
1531
1532                 if (!skb_page_frag_refill(fragsz, pfrag, GFP_KERNEL)) {
1533                         err = -ENOMEM;
1534                         goto free;
1535                 }
1536
1537                 skb_fill_page_desc(skb, i - 1, pfrag->page,
1538                                    pfrag->offset, fragsz);
1539                 page_ref_inc(pfrag->page);
1540                 pfrag->offset += fragsz;
1541         }
1542
1543         return skb;
1544 free:
1545         /* frees skb and all frags allocated with napi_alloc_frag() */
1546         napi_free_frags(&tfile->napi);
1547         return ERR_PTR(err);
1548 }
1549
1550 /* prepad is the amount to reserve at front.  len is length after that.
1551  * linear is a hint as to how much to copy (usually headers). */
1552 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1553                                      size_t prepad, size_t len,
1554                                      size_t linear, int noblock)
1555 {
1556         struct sock *sk = tfile->socket.sk;
1557         struct sk_buff *skb;
1558         int err;
1559
1560         /* Under a page?  Don't bother with paged skb. */
1561         if (prepad + len < PAGE_SIZE || !linear)
1562                 linear = len;
1563
1564         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1565                                    &err, 0);
1566         if (!skb)
1567                 return ERR_PTR(err);
1568
1569         skb_reserve(skb, prepad);
1570         skb_put(skb, linear);
1571         skb->data_len = len - linear;
1572         skb->len += len - linear;
1573
1574         return skb;
1575 }
1576
1577 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1578                            struct sk_buff *skb, int more)
1579 {
1580         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1581         struct sk_buff_head process_queue;
1582         u32 rx_batched = tun->rx_batched;
1583         bool rcv = false;
1584
1585         if (!rx_batched || (!more && skb_queue_empty(queue))) {
1586                 local_bh_disable();
1587                 netif_receive_skb(skb);
1588                 local_bh_enable();
1589                 return;
1590         }
1591
1592         spin_lock(&queue->lock);
1593         if (!more || skb_queue_len(queue) == rx_batched) {
1594                 __skb_queue_head_init(&process_queue);
1595                 skb_queue_splice_tail_init(queue, &process_queue);
1596                 rcv = true;
1597         } else {
1598                 __skb_queue_tail(queue, skb);
1599         }
1600         spin_unlock(&queue->lock);
1601
1602         if (rcv) {
1603                 struct sk_buff *nskb;
1604
1605                 local_bh_disable();
1606                 while ((nskb = __skb_dequeue(&process_queue)))
1607                         netif_receive_skb(nskb);
1608                 netif_receive_skb(skb);
1609                 local_bh_enable();
1610         }
1611 }
1612
1613 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1614                               int len, int noblock, bool zerocopy)
1615 {
1616         if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1617                 return false;
1618
1619         if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1620                 return false;
1621
1622         if (!noblock)
1623                 return false;
1624
1625         if (zerocopy)
1626                 return false;
1627
1628         if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1629             SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1630                 return false;
1631
1632         return true;
1633 }
1634
1635 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1636                                      struct tun_file *tfile,
1637                                      struct iov_iter *from,
1638                                      struct virtio_net_hdr *hdr,
1639                                      int len, int *skb_xdp)
1640 {
1641         struct page_frag *alloc_frag = &current->task_frag;
1642         struct sk_buff *skb;
1643         struct bpf_prog *xdp_prog;
1644         int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1645         unsigned int delta = 0;
1646         char *buf;
1647         size_t copied;
1648         int err, pad = TUN_RX_PAD;
1649
1650         rcu_read_lock();
1651         xdp_prog = rcu_dereference(tun->xdp_prog);
1652         if (xdp_prog)
1653                 pad += TUN_HEADROOM;
1654         buflen += SKB_DATA_ALIGN(len + pad);
1655         rcu_read_unlock();
1656
1657         alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1658         if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1659                 return ERR_PTR(-ENOMEM);
1660
1661         buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1662         copied = copy_page_from_iter(alloc_frag->page,
1663                                      alloc_frag->offset + pad,
1664                                      len, from);
1665         if (copied != len)
1666                 return ERR_PTR(-EFAULT);
1667
1668         /* There's a small window that XDP may be set after the check
1669          * of xdp_prog above, this should be rare and for simplicity
1670          * we do XDP on skb in case the headroom is not enough.
1671          */
1672         if (hdr->gso_type || !xdp_prog)
1673                 *skb_xdp = 1;
1674         else
1675                 *skb_xdp = 0;
1676
1677         preempt_disable();
1678         rcu_read_lock();
1679         xdp_prog = rcu_dereference(tun->xdp_prog);
1680         if (xdp_prog && !*skb_xdp) {
1681                 struct xdp_buff xdp;
1682                 void *orig_data;
1683                 u32 act;
1684
1685                 xdp.data_hard_start = buf;
1686                 xdp.data = buf + pad;
1687                 xdp_set_data_meta_invalid(&xdp);
1688                 xdp.data_end = xdp.data + len;
1689                 xdp.rxq = &tfile->xdp_rxq;
1690                 orig_data = xdp.data;
1691                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1692
1693                 switch (act) {
1694                 case XDP_REDIRECT:
1695                         get_page(alloc_frag->page);
1696                         alloc_frag->offset += buflen;
1697                         err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
1698                         xdp_do_flush_map();
1699                         if (err)
1700                                 goto err_redirect;
1701                         rcu_read_unlock();
1702                         preempt_enable();
1703                         return NULL;
1704                 case XDP_TX:
1705                         get_page(alloc_frag->page);
1706                         alloc_frag->offset += buflen;
1707                         if (tun_xdp_tx(tun->dev, &xdp))
1708                                 goto err_redirect;
1709                         tun_xdp_flush(tun->dev);
1710                         rcu_read_unlock();
1711                         preempt_enable();
1712                         return NULL;
1713                 case XDP_PASS:
1714                         delta = orig_data - xdp.data;
1715                         len = xdp.data_end - xdp.data;
1716                         break;
1717                 default:
1718                         bpf_warn_invalid_xdp_action(act);
1719                         /* fall through */
1720                 case XDP_ABORTED:
1721                         trace_xdp_exception(tun->dev, xdp_prog, act);
1722                         /* fall through */
1723                 case XDP_DROP:
1724                         goto err_xdp;
1725                 }
1726         }
1727
1728         skb = build_skb(buf, buflen);
1729         if (!skb) {
1730                 rcu_read_unlock();
1731                 preempt_enable();
1732                 return ERR_PTR(-ENOMEM);
1733         }
1734
1735         skb_reserve(skb, pad - delta);
1736         skb_put(skb, len);
1737         get_page(alloc_frag->page);
1738         alloc_frag->offset += buflen;
1739
1740         rcu_read_unlock();
1741         preempt_enable();
1742
1743         return skb;
1744
1745 err_redirect:
1746         put_page(alloc_frag->page);
1747 err_xdp:
1748         rcu_read_unlock();
1749         preempt_enable();
1750         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1751         return NULL;
1752 }
1753
1754 /* Get packet from user space buffer */
1755 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1756                             void *msg_control, struct iov_iter *from,
1757                             int noblock, bool more)
1758 {
1759         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1760         struct sk_buff *skb;
1761         size_t total_len = iov_iter_count(from);
1762         size_t len = total_len, align = tun->align, linear;
1763         struct virtio_net_hdr gso = { 0 };
1764         struct tun_pcpu_stats *stats;
1765         int good_linear;
1766         int copylen;
1767         bool zerocopy = false;
1768         int err;
1769         u32 rxhash = 0;
1770         int skb_xdp = 1;
1771         bool frags = tun_napi_frags_enabled(tun);
1772
1773         if (!(tun->dev->flags & IFF_UP))
1774                 return -EIO;
1775
1776         if (!(tun->flags & IFF_NO_PI)) {
1777                 if (len < sizeof(pi))
1778                         return -EINVAL;
1779                 len -= sizeof(pi);
1780
1781                 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1782                         return -EFAULT;
1783         }
1784
1785         if (tun->flags & IFF_VNET_HDR) {
1786                 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1787
1788                 if (len < vnet_hdr_sz)
1789                         return -EINVAL;
1790                 len -= vnet_hdr_sz;
1791
1792                 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1793                         return -EFAULT;
1794
1795                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1796                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1797                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1798
1799                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1800                         return -EINVAL;
1801                 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1802         }
1803
1804         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1805                 align += NET_IP_ALIGN;
1806                 if (unlikely(len < ETH_HLEN ||
1807                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1808                         return -EINVAL;
1809         }
1810
1811         good_linear = SKB_MAX_HEAD(align);
1812
1813         if (msg_control) {
1814                 struct iov_iter i = *from;
1815
1816                 /* There are 256 bytes to be copied in skb, so there is
1817                  * enough room for skb expand head in case it is used.
1818                  * The rest of the buffer is mapped from userspace.
1819                  */
1820                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1821                 if (copylen > good_linear)
1822                         copylen = good_linear;
1823                 linear = copylen;
1824                 iov_iter_advance(&i, copylen);
1825                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1826                         zerocopy = true;
1827         }
1828
1829         if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1830                 /* For the packet that is not easy to be processed
1831                  * (e.g gso or jumbo packet), we will do it at after
1832                  * skb was created with generic XDP routine.
1833                  */
1834                 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1835                 if (IS_ERR(skb)) {
1836                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1837                         return PTR_ERR(skb);
1838                 }
1839                 if (!skb)
1840                         return total_len;
1841         } else {
1842                 if (!zerocopy) {
1843                         copylen = len;
1844                         if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1845                                 linear = good_linear;
1846                         else
1847                                 linear = tun16_to_cpu(tun, gso.hdr_len);
1848                 }
1849
1850                 if (frags) {
1851                         mutex_lock(&tfile->napi_mutex);
1852                         skb = tun_napi_alloc_frags(tfile, copylen, from);
1853                         /* tun_napi_alloc_frags() enforces a layout for the skb.
1854                          * If zerocopy is enabled, then this layout will be
1855                          * overwritten by zerocopy_sg_from_iter().
1856                          */
1857                         zerocopy = false;
1858                 } else {
1859                         skb = tun_alloc_skb(tfile, align, copylen, linear,
1860                                             noblock);
1861                 }
1862
1863                 if (IS_ERR(skb)) {
1864                         if (PTR_ERR(skb) != -EAGAIN)
1865                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1866                         if (frags)
1867                                 mutex_unlock(&tfile->napi_mutex);
1868                         return PTR_ERR(skb);
1869                 }
1870
1871                 if (zerocopy)
1872                         err = zerocopy_sg_from_iter(skb, from);
1873                 else
1874                         err = skb_copy_datagram_from_iter(skb, 0, from, len);
1875
1876                 if (err) {
1877                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1878                         kfree_skb(skb);
1879                         if (frags) {
1880                                 tfile->napi.skb = NULL;
1881                                 mutex_unlock(&tfile->napi_mutex);
1882                         }
1883
1884                         return -EFAULT;
1885                 }
1886         }
1887
1888         if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1889                 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1890                 kfree_skb(skb);
1891                 if (frags) {
1892                         tfile->napi.skb = NULL;
1893                         mutex_unlock(&tfile->napi_mutex);
1894                 }
1895
1896                 return -EINVAL;
1897         }
1898
1899         switch (tun->flags & TUN_TYPE_MASK) {
1900         case IFF_TUN:
1901                 if (tun->flags & IFF_NO_PI) {
1902                         u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1903
1904                         switch (ip_version) {
1905                         case 4:
1906                                 pi.proto = htons(ETH_P_IP);
1907                                 break;
1908                         case 6:
1909                                 pi.proto = htons(ETH_P_IPV6);
1910                                 break;
1911                         default:
1912                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1913                                 kfree_skb(skb);
1914                                 return -EINVAL;
1915                         }
1916                 }
1917
1918                 skb_reset_mac_header(skb);
1919                 skb->protocol = pi.proto;
1920                 skb->dev = tun->dev;
1921                 break;
1922         case IFF_TAP:
1923                 if (!frags)
1924                         skb->protocol = eth_type_trans(skb, tun->dev);
1925                 break;
1926         }
1927
1928         /* copy skb_ubuf_info for callback when skb has no error */
1929         if (zerocopy) {
1930                 skb_shinfo(skb)->destructor_arg = msg_control;
1931                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1932                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1933         } else if (msg_control) {
1934                 struct ubuf_info *uarg = msg_control;
1935                 uarg->callback(uarg, false);
1936         }
1937
1938         skb_reset_network_header(skb);
1939         skb_probe_transport_header(skb, 0);
1940
1941         if (skb_xdp) {
1942                 struct bpf_prog *xdp_prog;
1943                 int ret;
1944
1945                 rcu_read_lock();
1946                 xdp_prog = rcu_dereference(tun->xdp_prog);
1947                 if (xdp_prog) {
1948                         ret = do_xdp_generic(xdp_prog, skb);
1949                         if (ret != XDP_PASS) {
1950                                 rcu_read_unlock();
1951                                 return total_len;
1952                         }
1953                 }
1954                 rcu_read_unlock();
1955         }
1956
1957         /* Compute the costly rx hash only if needed for flow updates.
1958          * We may get a very small possibility of OOO during switching, not
1959          * worth to optimize.
1960          */
1961         if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1962             !tfile->detached)
1963                 rxhash = __skb_get_hash_symmetric(skb);
1964
1965         if (frags) {
1966                 /* Exercise flow dissector code path. */
1967                 u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb));
1968
1969                 if (unlikely(headlen > skb_headlen(skb))) {
1970                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1971                         napi_free_frags(&tfile->napi);
1972                         mutex_unlock(&tfile->napi_mutex);
1973                         WARN_ON(1);
1974                         return -ENOMEM;
1975                 }
1976
1977                 local_bh_disable();
1978                 napi_gro_frags(&tfile->napi);
1979                 local_bh_enable();
1980                 mutex_unlock(&tfile->napi_mutex);
1981         } else if (tfile->napi_enabled) {
1982                 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1983                 int queue_len;
1984
1985                 spin_lock_bh(&queue->lock);
1986                 __skb_queue_tail(queue, skb);
1987                 queue_len = skb_queue_len(queue);
1988                 spin_unlock(&queue->lock);
1989
1990                 if (!more || queue_len > NAPI_POLL_WEIGHT)
1991                         napi_schedule(&tfile->napi);
1992
1993                 local_bh_enable();
1994         } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1995                 tun_rx_batched(tun, tfile, skb, more);
1996         } else {
1997                 netif_rx_ni(skb);
1998         }
1999
2000         stats = get_cpu_ptr(tun->pcpu_stats);
2001         u64_stats_update_begin(&stats->syncp);
2002         stats->rx_packets++;
2003         stats->rx_bytes += len;
2004         u64_stats_update_end(&stats->syncp);
2005         put_cpu_ptr(stats);
2006
2007         if (rxhash)
2008                 tun_flow_update(tun, rxhash, tfile);
2009
2010         return total_len;
2011 }
2012
2013 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
2014 {
2015         struct file *file = iocb->ki_filp;
2016         struct tun_file *tfile = file->private_data;
2017         struct tun_struct *tun = tun_get(tfile);
2018         ssize_t result;
2019
2020         if (!tun)
2021                 return -EBADFD;
2022
2023         result = tun_get_user(tun, tfile, NULL, from,
2024                               file->f_flags & O_NONBLOCK, false);
2025
2026         tun_put(tun);
2027         return result;
2028 }
2029
2030 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2031                                 struct tun_file *tfile,
2032                                 struct xdp_frame *xdp_frame,
2033                                 struct iov_iter *iter)
2034 {
2035         int vnet_hdr_sz = 0;
2036         size_t size = xdp_frame->len;
2037         struct tun_pcpu_stats *stats;
2038         size_t ret;
2039
2040         if (tun->flags & IFF_VNET_HDR) {
2041                 struct virtio_net_hdr gso = { 0 };
2042
2043                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2044                 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2045                         return -EINVAL;
2046                 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2047                              sizeof(gso)))
2048                         return -EFAULT;
2049                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2050         }
2051
2052         ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2053
2054         stats = get_cpu_ptr(tun->pcpu_stats);
2055         u64_stats_update_begin(&stats->syncp);
2056         stats->tx_packets++;
2057         stats->tx_bytes += ret;
2058         u64_stats_update_end(&stats->syncp);
2059         put_cpu_ptr(tun->pcpu_stats);
2060
2061         return ret;
2062 }
2063
2064 /* Put packet to the user space buffer */
2065 static ssize_t tun_put_user(struct tun_struct *tun,
2066                             struct tun_file *tfile,
2067                             struct sk_buff *skb,
2068                             struct iov_iter *iter)
2069 {
2070         struct tun_pi pi = { 0, skb->protocol };
2071         struct tun_pcpu_stats *stats;
2072         ssize_t total;
2073         int vlan_offset = 0;
2074         int vlan_hlen = 0;
2075         int vnet_hdr_sz = 0;
2076
2077         if (skb_vlan_tag_present(skb))
2078                 vlan_hlen = VLAN_HLEN;
2079
2080         if (tun->flags & IFF_VNET_HDR)
2081                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2082
2083         total = skb->len + vlan_hlen + vnet_hdr_sz;
2084
2085         if (!(tun->flags & IFF_NO_PI)) {
2086                 if (iov_iter_count(iter) < sizeof(pi))
2087                         return -EINVAL;
2088
2089                 total += sizeof(pi);
2090                 if (iov_iter_count(iter) < total) {
2091                         /* Packet will be striped */
2092                         pi.flags |= TUN_PKT_STRIP;
2093                 }
2094
2095                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2096                         return -EFAULT;
2097         }
2098
2099         if (vnet_hdr_sz) {
2100                 struct virtio_net_hdr gso;
2101
2102                 if (iov_iter_count(iter) < vnet_hdr_sz)
2103                         return -EINVAL;
2104
2105                 if (virtio_net_hdr_from_skb(skb, &gso,
2106                                             tun_is_little_endian(tun), true)) {
2107                         struct skb_shared_info *sinfo = skb_shinfo(skb);
2108                         pr_err("unexpected GSO type: "
2109                                "0x%x, gso_size %d, hdr_len %d\n",
2110                                sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2111                                tun16_to_cpu(tun, gso.hdr_len));
2112                         print_hex_dump(KERN_ERR, "tun: ",
2113                                        DUMP_PREFIX_NONE,
2114                                        16, 1, skb->head,
2115                                        min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2116                         WARN_ON_ONCE(1);
2117                         return -EINVAL;
2118                 }
2119
2120                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2121                         return -EFAULT;
2122
2123                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2124         }
2125
2126         if (vlan_hlen) {
2127                 int ret;
2128                 struct veth veth;
2129
2130                 veth.h_vlan_proto = skb->vlan_proto;
2131                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2132
2133                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2134
2135                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2136                 if (ret || !iov_iter_count(iter))
2137                         goto done;
2138
2139                 ret = copy_to_iter(&veth, sizeof(veth), iter);
2140                 if (ret != sizeof(veth) || !iov_iter_count(iter))
2141                         goto done;
2142         }
2143
2144         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2145
2146 done:
2147         /* caller is in process context, */
2148         stats = get_cpu_ptr(tun->pcpu_stats);
2149         u64_stats_update_begin(&stats->syncp);
2150         stats->tx_packets++;
2151         stats->tx_bytes += skb->len + vlan_hlen;
2152         u64_stats_update_end(&stats->syncp);
2153         put_cpu_ptr(tun->pcpu_stats);
2154
2155         return total;
2156 }
2157
2158 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2159 {
2160         DECLARE_WAITQUEUE(wait, current);
2161         void *ptr = NULL;
2162         int error = 0;
2163
2164         ptr = ptr_ring_consume(&tfile->tx_ring);
2165         if (ptr)
2166                 goto out;
2167         if (noblock) {
2168                 error = -EAGAIN;
2169                 goto out;
2170         }
2171
2172         add_wait_queue(&tfile->wq.wait, &wait);
2173         current->state = TASK_INTERRUPTIBLE;
2174
2175         while (1) {
2176                 ptr = ptr_ring_consume(&tfile->tx_ring);
2177                 if (ptr)
2178                         break;
2179                 if (signal_pending(current)) {
2180                         error = -ERESTARTSYS;
2181                         break;
2182                 }
2183                 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2184                         error = -EFAULT;
2185                         break;
2186                 }
2187
2188                 schedule();
2189         }
2190
2191         current->state = TASK_RUNNING;
2192         remove_wait_queue(&tfile->wq.wait, &wait);
2193
2194 out:
2195         *err = error;
2196         return ptr;
2197 }
2198
2199 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2200                            struct iov_iter *to,
2201                            int noblock, void *ptr)
2202 {
2203         ssize_t ret;
2204         int err;
2205
2206         tun_debug(KERN_INFO, tun, "tun_do_read\n");
2207
2208         if (!iov_iter_count(to)) {
2209                 tun_ptr_free(ptr);
2210                 return 0;
2211         }
2212
2213         if (!ptr) {
2214                 /* Read frames from ring */
2215                 ptr = tun_ring_recv(tfile, noblock, &err);
2216                 if (!ptr)
2217                         return err;
2218         }
2219
2220         if (tun_is_xdp_frame(ptr)) {
2221                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2222
2223                 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2224                 xdp_return_frame(xdpf);
2225         } else {
2226                 struct sk_buff *skb = ptr;
2227
2228                 ret = tun_put_user(tun, tfile, skb, to);
2229                 if (unlikely(ret < 0))
2230                         kfree_skb(skb);
2231                 else
2232                         consume_skb(skb);
2233         }
2234
2235         return ret;
2236 }
2237
2238 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2239 {
2240         struct file *file = iocb->ki_filp;
2241         struct tun_file *tfile = file->private_data;
2242         struct tun_struct *tun = tun_get(tfile);
2243         ssize_t len = iov_iter_count(to), ret;
2244
2245         if (!tun)
2246                 return -EBADFD;
2247         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2248         ret = min_t(ssize_t, ret, len);
2249         if (ret > 0)
2250                 iocb->ki_pos = ret;
2251         tun_put(tun);
2252         return ret;
2253 }
2254
2255 static void tun_prog_free(struct rcu_head *rcu)
2256 {
2257         struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2258
2259         bpf_prog_destroy(prog->prog);
2260         kfree(prog);
2261 }
2262
2263 static int __tun_set_ebpf(struct tun_struct *tun,
2264                           struct tun_prog __rcu **prog_p,
2265                           struct bpf_prog *prog)
2266 {
2267         struct tun_prog *old, *new = NULL;
2268
2269         if (prog) {
2270                 new = kmalloc(sizeof(*new), GFP_KERNEL);
2271                 if (!new)
2272                         return -ENOMEM;
2273                 new->prog = prog;
2274         }
2275
2276         spin_lock_bh(&tun->lock);
2277         old = rcu_dereference_protected(*prog_p,
2278                                         lockdep_is_held(&tun->lock));
2279         rcu_assign_pointer(*prog_p, new);
2280         spin_unlock_bh(&tun->lock);
2281
2282         if (old)
2283                 call_rcu(&old->rcu, tun_prog_free);
2284
2285         return 0;
2286 }
2287
2288 static void tun_free_netdev(struct net_device *dev)
2289 {
2290         struct tun_struct *tun = netdev_priv(dev);
2291
2292         BUG_ON(!(list_empty(&tun->disabled)));
2293         free_percpu(tun->pcpu_stats);
2294         tun_flow_uninit(tun);
2295         security_tun_dev_free_security(tun->security);
2296         __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2297         __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2298 }
2299
2300 static void tun_setup(struct net_device *dev)
2301 {
2302         struct tun_struct *tun = netdev_priv(dev);
2303
2304         tun->owner = INVALID_UID;
2305         tun->group = INVALID_GID;
2306
2307         dev->ethtool_ops = &tun_ethtool_ops;
2308         dev->needs_free_netdev = true;
2309         dev->priv_destructor = tun_free_netdev;
2310         /* We prefer our own queue length */
2311         dev->tx_queue_len = TUN_READQ_SIZE;
2312 }
2313
2314 /* Trivial set of netlink ops to allow deleting tun or tap
2315  * device with netlink.
2316  */
2317 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2318                         struct netlink_ext_ack *extack)
2319 {
2320         return -EINVAL;
2321 }
2322
2323 static size_t tun_get_size(const struct net_device *dev)
2324 {
2325         BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2326         BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2327
2328         return nla_total_size(sizeof(uid_t)) + /* OWNER */
2329                nla_total_size(sizeof(gid_t)) + /* GROUP */
2330                nla_total_size(sizeof(u8)) + /* TYPE */
2331                nla_total_size(sizeof(u8)) + /* PI */
2332                nla_total_size(sizeof(u8)) + /* VNET_HDR */
2333                nla_total_size(sizeof(u8)) + /* PERSIST */
2334                nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2335                nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2336                nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2337                0;
2338 }
2339
2340 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2341 {
2342         struct tun_struct *tun = netdev_priv(dev);
2343
2344         if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2345                 goto nla_put_failure;
2346         if (uid_valid(tun->owner) &&
2347             nla_put_u32(skb, IFLA_TUN_OWNER,
2348                         from_kuid_munged(current_user_ns(), tun->owner)))
2349                 goto nla_put_failure;
2350         if (gid_valid(tun->group) &&
2351             nla_put_u32(skb, IFLA_TUN_GROUP,
2352                         from_kgid_munged(current_user_ns(), tun->group)))
2353                 goto nla_put_failure;
2354         if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2355                 goto nla_put_failure;
2356         if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2357                 goto nla_put_failure;
2358         if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2359                 goto nla_put_failure;
2360         if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2361                        !!(tun->flags & IFF_MULTI_QUEUE)))
2362                 goto nla_put_failure;
2363         if (tun->flags & IFF_MULTI_QUEUE) {
2364                 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2365                         goto nla_put_failure;
2366                 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2367                                 tun->numdisabled))
2368                         goto nla_put_failure;
2369         }
2370
2371         return 0;
2372
2373 nla_put_failure:
2374         return -EMSGSIZE;
2375 }
2376
2377 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2378         .kind           = DRV_NAME,
2379         .priv_size      = sizeof(struct tun_struct),
2380         .setup          = tun_setup,
2381         .validate       = tun_validate,
2382         .get_size       = tun_get_size,
2383         .fill_info      = tun_fill_info,
2384 };
2385
2386 static void tun_sock_write_space(struct sock *sk)
2387 {
2388         struct tun_file *tfile;
2389         wait_queue_head_t *wqueue;
2390
2391         if (!sock_writeable(sk))
2392                 return;
2393
2394         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2395                 return;
2396
2397         wqueue = sk_sleep(sk);
2398         if (wqueue && waitqueue_active(wqueue))
2399                 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2400                                                 EPOLLWRNORM | EPOLLWRBAND);
2401
2402         tfile = container_of(sk, struct tun_file, sk);
2403         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2404 }
2405
2406 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2407 {
2408         int ret;
2409         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2410         struct tun_struct *tun = tun_get(tfile);
2411
2412         if (!tun)
2413                 return -EBADFD;
2414
2415         ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
2416                            m->msg_flags & MSG_DONTWAIT,
2417                            m->msg_flags & MSG_MORE);
2418         tun_put(tun);
2419         return ret;
2420 }
2421
2422 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2423                        int flags)
2424 {
2425         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2426         struct tun_struct *tun = tun_get(tfile);
2427         void *ptr = m->msg_control;
2428         int ret;
2429
2430         if (!tun) {
2431                 ret = -EBADFD;
2432                 goto out_free;
2433         }
2434
2435         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2436                 ret = -EINVAL;
2437                 goto out_put_tun;
2438         }
2439         if (flags & MSG_ERRQUEUE) {
2440                 ret = sock_recv_errqueue(sock->sk, m, total_len,
2441                                          SOL_PACKET, TUN_TX_TIMESTAMP);
2442                 goto out;
2443         }
2444         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2445         if (ret > (ssize_t)total_len) {
2446                 m->msg_flags |= MSG_TRUNC;
2447                 ret = flags & MSG_TRUNC ? ret : total_len;
2448         }
2449 out:
2450         tun_put(tun);
2451         return ret;
2452
2453 out_put_tun:
2454         tun_put(tun);
2455 out_free:
2456         tun_ptr_free(ptr);
2457         return ret;
2458 }
2459
2460 static int tun_ptr_peek_len(void *ptr)
2461 {
2462         if (likely(ptr)) {
2463                 if (tun_is_xdp_frame(ptr)) {
2464                         struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2465
2466                         return xdpf->len;
2467                 }
2468                 return __skb_array_len_with_tag(ptr);
2469         } else {
2470                 return 0;
2471         }
2472 }
2473
2474 static int tun_peek_len(struct socket *sock)
2475 {
2476         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2477         struct tun_struct *tun;
2478         int ret = 0;
2479
2480         tun = tun_get(tfile);
2481         if (!tun)
2482                 return 0;
2483
2484         ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2485         tun_put(tun);
2486
2487         return ret;
2488 }
2489
2490 /* Ops structure to mimic raw sockets with tun */
2491 static const struct proto_ops tun_socket_ops = {
2492         .peek_len = tun_peek_len,
2493         .sendmsg = tun_sendmsg,
2494         .recvmsg = tun_recvmsg,
2495 };
2496
2497 static struct proto tun_proto = {
2498         .name           = "tun",
2499         .owner          = THIS_MODULE,
2500         .obj_size       = sizeof(struct tun_file),
2501 };
2502
2503 static int tun_flags(struct tun_struct *tun)
2504 {
2505         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2506 }
2507
2508 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2509                               char *buf)
2510 {
2511         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2512         return sprintf(buf, "0x%x\n", tun_flags(tun));
2513 }
2514
2515 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2516                               char *buf)
2517 {
2518         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2519         return uid_valid(tun->owner)?
2520                 sprintf(buf, "%u\n",
2521                         from_kuid_munged(current_user_ns(), tun->owner)):
2522                 sprintf(buf, "-1\n");
2523 }
2524
2525 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2526                               char *buf)
2527 {
2528         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2529         return gid_valid(tun->group) ?
2530                 sprintf(buf, "%u\n",
2531                         from_kgid_munged(current_user_ns(), tun->group)):
2532                 sprintf(buf, "-1\n");
2533 }
2534
2535 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2536 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2537 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2538
2539 static struct attribute *tun_dev_attrs[] = {
2540         &dev_attr_tun_flags.attr,
2541         &dev_attr_owner.attr,
2542         &dev_attr_group.attr,
2543         NULL
2544 };
2545
2546 static const struct attribute_group tun_attr_group = {
2547         .attrs = tun_dev_attrs
2548 };
2549
2550 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2551 {
2552         struct tun_struct *tun;
2553         struct tun_file *tfile = file->private_data;
2554         struct net_device *dev;
2555         int err;
2556
2557         if (tfile->detached)
2558                 return -EINVAL;
2559
2560         if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2561                 if (!capable(CAP_NET_ADMIN))
2562                         return -EPERM;
2563
2564                 if (!(ifr->ifr_flags & IFF_NAPI) ||
2565                     (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2566                         return -EINVAL;
2567         }
2568
2569         dev = __dev_get_by_name(net, ifr->ifr_name);
2570         if (dev) {
2571                 if (ifr->ifr_flags & IFF_TUN_EXCL)
2572                         return -EBUSY;
2573                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2574                         tun = netdev_priv(dev);
2575                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2576                         tun = netdev_priv(dev);
2577                 else
2578                         return -EINVAL;
2579
2580                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2581                     !!(tun->flags & IFF_MULTI_QUEUE))
2582                         return -EINVAL;
2583
2584                 if (tun_not_capable(tun))
2585                         return -EPERM;
2586                 err = security_tun_dev_open(tun->security);
2587                 if (err < 0)
2588                         return err;
2589
2590                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2591                                  ifr->ifr_flags & IFF_NAPI);
2592                 if (err < 0)
2593                         return err;
2594
2595                 if (tun->flags & IFF_MULTI_QUEUE &&
2596                     (tun->numqueues + tun->numdisabled > 1)) {
2597                         /* One or more queue has already been attached, no need
2598                          * to initialize the device again.
2599                          */
2600                         netdev_state_change(dev);
2601                         return 0;
2602                 }
2603
2604                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2605                               (ifr->ifr_flags & TUN_FEATURES);
2606
2607                 netdev_state_change(dev);
2608         } else {
2609                 char *name;
2610                 unsigned long flags = 0;
2611                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2612                              MAX_TAP_QUEUES : 1;
2613
2614                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2615                         return -EPERM;
2616                 err = security_tun_dev_create();
2617                 if (err < 0)
2618                         return err;
2619
2620                 /* Set dev type */
2621                 if (ifr->ifr_flags & IFF_TUN) {
2622                         /* TUN device */
2623                         flags |= IFF_TUN;
2624                         name = "tun%d";
2625                 } else if (ifr->ifr_flags & IFF_TAP) {
2626                         /* TAP device */
2627                         flags |= IFF_TAP;
2628                         name = "tap%d";
2629                 } else
2630                         return -EINVAL;
2631
2632                 if (*ifr->ifr_name)
2633                         name = ifr->ifr_name;
2634
2635                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2636                                        NET_NAME_UNKNOWN, tun_setup, queues,
2637                                        queues);
2638
2639                 if (!dev)
2640                         return -ENOMEM;
2641                 err = dev_get_valid_name(net, dev, name);
2642                 if (err < 0)
2643                         goto err_free_dev;
2644
2645                 dev_net_set(dev, net);
2646                 dev->rtnl_link_ops = &tun_link_ops;
2647                 dev->ifindex = tfile->ifindex;
2648                 dev->sysfs_groups[0] = &tun_attr_group;
2649
2650                 tun = netdev_priv(dev);
2651                 tun->dev = dev;
2652                 tun->flags = flags;
2653                 tun->txflt.count = 0;
2654                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2655
2656                 tun->align = NET_SKB_PAD;
2657                 tun->filter_attached = false;
2658                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2659                 tun->rx_batched = 0;
2660                 RCU_INIT_POINTER(tun->steering_prog, NULL);
2661
2662                 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2663                 if (!tun->pcpu_stats) {
2664                         err = -ENOMEM;
2665                         goto err_free_dev;
2666                 }
2667
2668                 spin_lock_init(&tun->lock);
2669
2670                 err = security_tun_dev_alloc_security(&tun->security);
2671                 if (err < 0)
2672                         goto err_free_stat;
2673
2674                 tun_net_init(dev);
2675                 tun_flow_init(tun);
2676
2677                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2678                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2679                                    NETIF_F_HW_VLAN_STAG_TX;
2680                 dev->features = dev->hw_features | NETIF_F_LLTX;
2681                 dev->vlan_features = dev->features &
2682                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
2683                                        NETIF_F_HW_VLAN_STAG_TX);
2684
2685                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2686                               (ifr->ifr_flags & TUN_FEATURES);
2687
2688                 INIT_LIST_HEAD(&tun->disabled);
2689                 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI);
2690                 if (err < 0)
2691                         goto err_free_flow;
2692
2693                 err = register_netdevice(tun->dev);
2694                 if (err < 0)
2695                         goto err_detach;
2696         }
2697
2698         netif_carrier_on(tun->dev);
2699
2700         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2701
2702         /* Make sure persistent devices do not get stuck in
2703          * xoff state.
2704          */
2705         if (netif_running(tun->dev))
2706                 netif_tx_wake_all_queues(tun->dev);
2707
2708         strcpy(ifr->ifr_name, tun->dev->name);
2709         return 0;
2710
2711 err_detach:
2712         tun_detach_all(dev);
2713         /* register_netdevice() already called tun_free_netdev() */
2714         goto err_free_dev;
2715
2716 err_free_flow:
2717         tun_flow_uninit(tun);
2718         security_tun_dev_free_security(tun->security);
2719 err_free_stat:
2720         free_percpu(tun->pcpu_stats);
2721 err_free_dev:
2722         free_netdev(dev);
2723         return err;
2724 }
2725
2726 static void tun_get_iff(struct net *net, struct tun_struct *tun,
2727                        struct ifreq *ifr)
2728 {
2729         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2730
2731         strcpy(ifr->ifr_name, tun->dev->name);
2732
2733         ifr->ifr_flags = tun_flags(tun);
2734
2735 }
2736
2737 /* This is like a cut-down ethtool ops, except done via tun fd so no
2738  * privs required. */
2739 static int set_offload(struct tun_struct *tun, unsigned long arg)
2740 {
2741         netdev_features_t features = 0;
2742
2743         if (arg & TUN_F_CSUM) {
2744                 features |= NETIF_F_HW_CSUM;
2745                 arg &= ~TUN_F_CSUM;
2746
2747                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2748                         if (arg & TUN_F_TSO_ECN) {
2749                                 features |= NETIF_F_TSO_ECN;
2750                                 arg &= ~TUN_F_TSO_ECN;
2751                         }
2752                         if (arg & TUN_F_TSO4)
2753                                 features |= NETIF_F_TSO;
2754                         if (arg & TUN_F_TSO6)
2755                                 features |= NETIF_F_TSO6;
2756                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2757                 }
2758
2759                 arg &= ~TUN_F_UFO;
2760         }
2761
2762         /* This gives the user a way to test for new features in future by
2763          * trying to set them. */
2764         if (arg)
2765                 return -EINVAL;
2766
2767         tun->set_features = features;
2768         tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2769         tun->dev->wanted_features |= features;
2770         netdev_update_features(tun->dev);
2771
2772         return 0;
2773 }
2774
2775 static void tun_detach_filter(struct tun_struct *tun, int n)
2776 {
2777         int i;
2778         struct tun_file *tfile;
2779
2780         for (i = 0; i < n; i++) {
2781                 tfile = rtnl_dereference(tun->tfiles[i]);
2782                 lock_sock(tfile->socket.sk);
2783                 sk_detach_filter(tfile->socket.sk);
2784                 release_sock(tfile->socket.sk);
2785         }
2786
2787         tun->filter_attached = false;
2788 }
2789
2790 static int tun_attach_filter(struct tun_struct *tun)
2791 {
2792         int i, ret = 0;
2793         struct tun_file *tfile;
2794
2795         for (i = 0; i < tun->numqueues; i++) {
2796                 tfile = rtnl_dereference(tun->tfiles[i]);
2797                 lock_sock(tfile->socket.sk);
2798                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2799                 release_sock(tfile->socket.sk);
2800                 if (ret) {
2801                         tun_detach_filter(tun, i);
2802                         return ret;
2803                 }
2804         }
2805
2806         tun->filter_attached = true;
2807         return ret;
2808 }
2809
2810 static void tun_set_sndbuf(struct tun_struct *tun)
2811 {
2812         struct tun_file *tfile;
2813         int i;
2814
2815         for (i = 0; i < tun->numqueues; i++) {
2816                 tfile = rtnl_dereference(tun->tfiles[i]);
2817                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2818         }
2819 }
2820
2821 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2822 {
2823         struct tun_file *tfile = file->private_data;
2824         struct tun_struct *tun;
2825         int ret = 0;
2826
2827         rtnl_lock();
2828
2829         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2830                 tun = tfile->detached;
2831                 if (!tun) {
2832                         ret = -EINVAL;
2833                         goto unlock;
2834                 }
2835                 ret = security_tun_dev_attach_queue(tun->security);
2836                 if (ret < 0)
2837                         goto unlock;
2838                 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI);
2839         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2840                 tun = rtnl_dereference(tfile->tun);
2841                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2842                         ret = -EINVAL;
2843                 else
2844                         __tun_detach(tfile, false);
2845         } else
2846                 ret = -EINVAL;
2847
2848         if (ret >= 0)
2849                 netdev_state_change(tun->dev);
2850
2851 unlock:
2852         rtnl_unlock();
2853         return ret;
2854 }
2855
2856 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
2857                         void __user *data)
2858 {
2859         struct bpf_prog *prog;
2860         int fd;
2861
2862         if (copy_from_user(&fd, data, sizeof(fd)))
2863                 return -EFAULT;
2864
2865         if (fd == -1) {
2866                 prog = NULL;
2867         } else {
2868                 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
2869                 if (IS_ERR(prog))
2870                         return PTR_ERR(prog);
2871         }
2872
2873         return __tun_set_ebpf(tun, prog_p, prog);
2874 }
2875
2876 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2877                             unsigned long arg, int ifreq_len)
2878 {
2879         struct tun_file *tfile = file->private_data;
2880         struct net *net = sock_net(&tfile->sk);
2881         struct tun_struct *tun;
2882         void __user* argp = (void __user*)arg;
2883         struct ifreq ifr;
2884         kuid_t owner;
2885         kgid_t group;
2886         int sndbuf;
2887         int vnet_hdr_sz;
2888         unsigned int ifindex;
2889         int le;
2890         int ret;
2891         bool do_notify = false;
2892
2893         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
2894             (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
2895                 if (copy_from_user(&ifr, argp, ifreq_len))
2896                         return -EFAULT;
2897         } else {
2898                 memset(&ifr, 0, sizeof(ifr));
2899         }
2900         if (cmd == TUNGETFEATURES) {
2901                 /* Currently this just means: "what IFF flags are valid?".
2902                  * This is needed because we never checked for invalid flags on
2903                  * TUNSETIFF.
2904                  */
2905                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2906                                 (unsigned int __user*)argp);
2907         } else if (cmd == TUNSETQUEUE) {
2908                 return tun_set_queue(file, &ifr);
2909         } else if (cmd == SIOCGSKNS) {
2910                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2911                         return -EPERM;
2912                 return open_related_ns(&net->ns, get_net_ns);
2913         }
2914
2915         ret = 0;
2916         rtnl_lock();
2917
2918         tun = tun_get(tfile);
2919         if (cmd == TUNSETIFF) {
2920                 ret = -EEXIST;
2921                 if (tun)
2922                         goto unlock;
2923
2924                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2925
2926                 ret = tun_set_iff(net, file, &ifr);
2927
2928                 if (ret)
2929                         goto unlock;
2930
2931                 if (copy_to_user(argp, &ifr, ifreq_len))
2932                         ret = -EFAULT;
2933                 goto unlock;
2934         }
2935         if (cmd == TUNSETIFINDEX) {
2936                 ret = -EPERM;
2937                 if (tun)
2938                         goto unlock;
2939
2940                 ret = -EFAULT;
2941                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2942                         goto unlock;
2943
2944                 ret = 0;
2945                 tfile->ifindex = ifindex;
2946                 goto unlock;
2947         }
2948
2949         ret = -EBADFD;
2950         if (!tun)
2951                 goto unlock;
2952
2953         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2954
2955         ret = 0;
2956         switch (cmd) {
2957         case TUNGETIFF:
2958                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2959
2960                 if (tfile->detached)
2961                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
2962                 if (!tfile->socket.sk->sk_filter)
2963                         ifr.ifr_flags |= IFF_NOFILTER;
2964
2965                 if (copy_to_user(argp, &ifr, ifreq_len))
2966                         ret = -EFAULT;
2967                 break;
2968
2969         case TUNSETNOCSUM:
2970                 /* Disable/Enable checksum */
2971
2972                 /* [unimplemented] */
2973                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2974                           arg ? "disabled" : "enabled");
2975                 break;
2976
2977         case TUNSETPERSIST:
2978                 /* Disable/Enable persist mode. Keep an extra reference to the
2979                  * module to prevent the module being unprobed.
2980                  */
2981                 if (arg && !(tun->flags & IFF_PERSIST)) {
2982                         tun->flags |= IFF_PERSIST;
2983                         __module_get(THIS_MODULE);
2984                         do_notify = true;
2985                 }
2986                 if (!arg && (tun->flags & IFF_PERSIST)) {
2987                         tun->flags &= ~IFF_PERSIST;
2988                         module_put(THIS_MODULE);
2989                         do_notify = true;
2990                 }
2991
2992                 tun_debug(KERN_INFO, tun, "persist %s\n",
2993                           arg ? "enabled" : "disabled");
2994                 break;
2995
2996         case TUNSETOWNER:
2997                 /* Set owner of the device */
2998                 owner = make_kuid(current_user_ns(), arg);
2999                 if (!uid_valid(owner)) {
3000                         ret = -EINVAL;
3001                         break;
3002                 }
3003                 tun->owner = owner;
3004                 do_notify = true;
3005                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
3006                           from_kuid(&init_user_ns, tun->owner));
3007                 break;
3008
3009         case TUNSETGROUP:
3010                 /* Set group of the device */
3011                 group = make_kgid(current_user_ns(), arg);
3012                 if (!gid_valid(group)) {
3013                         ret = -EINVAL;
3014                         break;
3015                 }
3016                 tun->group = group;
3017                 do_notify = true;
3018                 tun_debug(KERN_INFO, tun, "group set to %u\n",
3019                           from_kgid(&init_user_ns, tun->group));
3020                 break;
3021
3022         case TUNSETLINK:
3023                 /* Only allow setting the type when the interface is down */
3024                 if (tun->dev->flags & IFF_UP) {
3025                         tun_debug(KERN_INFO, tun,
3026                                   "Linktype set failed because interface is up\n");
3027                         ret = -EBUSY;
3028                 } else {
3029                         tun->dev->type = (int) arg;
3030                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
3031                                   tun->dev->type);
3032                         ret = 0;
3033                 }
3034                 break;
3035
3036 #ifdef TUN_DEBUG
3037         case TUNSETDEBUG:
3038                 tun->debug = arg;
3039                 break;
3040 #endif
3041         case TUNSETOFFLOAD:
3042                 ret = set_offload(tun, arg);
3043                 break;
3044
3045         case TUNSETTXFILTER:
3046                 /* Can be set only for TAPs */
3047                 ret = -EINVAL;
3048                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3049                         break;
3050                 ret = update_filter(&tun->txflt, (void __user *)arg);
3051                 break;
3052
3053         case SIOCGIFHWADDR:
3054                 /* Get hw address */
3055                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3056                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3057                 if (copy_to_user(argp, &ifr, ifreq_len))
3058                         ret = -EFAULT;
3059                 break;
3060
3061         case SIOCSIFHWADDR:
3062                 /* Set hw address */
3063                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
3064                           ifr.ifr_hwaddr.sa_data);
3065
3066                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
3067                 break;
3068
3069         case TUNGETSNDBUF:
3070                 sndbuf = tfile->socket.sk->sk_sndbuf;
3071                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3072                         ret = -EFAULT;
3073                 break;
3074
3075         case TUNSETSNDBUF:
3076                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3077                         ret = -EFAULT;
3078                         break;
3079                 }
3080                 if (sndbuf <= 0) {
3081                         ret = -EINVAL;
3082                         break;
3083                 }
3084
3085                 tun->sndbuf = sndbuf;
3086                 tun_set_sndbuf(tun);
3087                 break;
3088
3089         case TUNGETVNETHDRSZ:
3090                 vnet_hdr_sz = tun->vnet_hdr_sz;
3091                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3092                         ret = -EFAULT;
3093                 break;
3094
3095         case TUNSETVNETHDRSZ:
3096                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3097                         ret = -EFAULT;
3098                         break;
3099                 }
3100                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3101                         ret = -EINVAL;
3102                         break;
3103                 }
3104
3105                 tun->vnet_hdr_sz = vnet_hdr_sz;
3106                 break;
3107
3108         case TUNGETVNETLE:
3109                 le = !!(tun->flags & TUN_VNET_LE);
3110                 if (put_user(le, (int __user *)argp))
3111                         ret = -EFAULT;
3112                 break;
3113
3114         case TUNSETVNETLE:
3115                 if (get_user(le, (int __user *)argp)) {
3116                         ret = -EFAULT;
3117                         break;
3118                 }
3119                 if (le)
3120                         tun->flags |= TUN_VNET_LE;
3121                 else
3122                         tun->flags &= ~TUN_VNET_LE;
3123                 break;
3124
3125         case TUNGETVNETBE:
3126                 ret = tun_get_vnet_be(tun, argp);
3127                 break;
3128
3129         case TUNSETVNETBE:
3130                 ret = tun_set_vnet_be(tun, argp);
3131                 break;
3132
3133         case TUNATTACHFILTER:
3134                 /* Can be set only for TAPs */
3135                 ret = -EINVAL;
3136                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3137                         break;
3138                 ret = -EFAULT;
3139                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3140                         break;
3141
3142                 ret = tun_attach_filter(tun);
3143                 break;
3144
3145         case TUNDETACHFILTER:
3146                 /* Can be set only for TAPs */
3147                 ret = -EINVAL;
3148                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3149                         break;
3150                 ret = 0;
3151                 tun_detach_filter(tun, tun->numqueues);
3152                 break;
3153
3154         case TUNGETFILTER:
3155                 ret = -EINVAL;
3156                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3157                         break;
3158                 ret = -EFAULT;
3159                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3160                         break;
3161                 ret = 0;
3162                 break;
3163
3164         case TUNSETSTEERINGEBPF:
3165                 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3166                 break;
3167
3168         case TUNSETFILTEREBPF:
3169                 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3170                 break;
3171
3172         default:
3173                 ret = -EINVAL;
3174                 break;
3175         }
3176
3177         if (do_notify)
3178                 netdev_state_change(tun->dev);
3179
3180 unlock:
3181         rtnl_unlock();
3182         if (tun)
3183                 tun_put(tun);
3184         return ret;
3185 }
3186
3187 static long tun_chr_ioctl(struct file *file,
3188                           unsigned int cmd, unsigned long arg)
3189 {
3190         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3191 }
3192
3193 #ifdef CONFIG_COMPAT
3194 static long tun_chr_compat_ioctl(struct file *file,
3195                          unsigned int cmd, unsigned long arg)
3196 {
3197         switch (cmd) {
3198         case TUNSETIFF:
3199         case TUNGETIFF:
3200         case TUNSETTXFILTER:
3201         case TUNGETSNDBUF:
3202         case TUNSETSNDBUF:
3203         case SIOCGIFHWADDR:
3204         case SIOCSIFHWADDR:
3205                 arg = (unsigned long)compat_ptr(arg);
3206                 break;
3207         default:
3208                 arg = (compat_ulong_t)arg;
3209                 break;
3210         }
3211
3212         /*
3213          * compat_ifreq is shorter than ifreq, so we must not access beyond
3214          * the end of that structure. All fields that are used in this
3215          * driver are compatible though, we don't need to convert the
3216          * contents.
3217          */
3218         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3219 }
3220 #endif /* CONFIG_COMPAT */
3221
3222 static int tun_chr_fasync(int fd, struct file *file, int on)
3223 {
3224         struct tun_file *tfile = file->private_data;
3225         int ret;
3226
3227         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3228                 goto out;
3229
3230         if (on) {
3231                 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
3232                 tfile->flags |= TUN_FASYNC;
3233         } else
3234                 tfile->flags &= ~TUN_FASYNC;
3235         ret = 0;
3236 out:
3237         return ret;
3238 }
3239
3240 static int tun_chr_open(struct inode *inode, struct file * file)
3241 {
3242         struct net *net = current->nsproxy->net_ns;
3243         struct tun_file *tfile;
3244
3245         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
3246
3247         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3248                                             &tun_proto, 0);
3249         if (!tfile)
3250                 return -ENOMEM;
3251         if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3252                 sk_free(&tfile->sk);
3253                 return -ENOMEM;
3254         }
3255
3256         RCU_INIT_POINTER(tfile->tun, NULL);
3257         tfile->flags = 0;
3258         tfile->ifindex = 0;
3259
3260         init_waitqueue_head(&tfile->wq.wait);
3261         RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
3262
3263         tfile->socket.file = file;
3264         tfile->socket.ops = &tun_socket_ops;
3265
3266         sock_init_data(&tfile->socket, &tfile->sk);
3267
3268         tfile->sk.sk_write_space = tun_sock_write_space;
3269         tfile->sk.sk_sndbuf = INT_MAX;
3270
3271         file->private_data = tfile;
3272         INIT_LIST_HEAD(&tfile->next);
3273
3274         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3275
3276         return 0;
3277 }
3278
3279 static int tun_chr_close(struct inode *inode, struct file *file)
3280 {
3281         struct tun_file *tfile = file->private_data;
3282
3283         tun_detach(tfile, true);
3284
3285         return 0;
3286 }
3287
3288 #ifdef CONFIG_PROC_FS
3289 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3290 {
3291         struct tun_file *tfile = file->private_data;
3292         struct tun_struct *tun;
3293         struct ifreq ifr;
3294
3295         memset(&ifr, 0, sizeof(ifr));
3296
3297         rtnl_lock();
3298         tun = tun_get(tfile);
3299         if (tun)
3300                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
3301         rtnl_unlock();
3302
3303         if (tun)
3304                 tun_put(tun);
3305
3306         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3307 }
3308 #endif
3309
3310 static const struct file_operations tun_fops = {
3311         .owner  = THIS_MODULE,
3312         .llseek = no_llseek,
3313         .read_iter  = tun_chr_read_iter,
3314         .write_iter = tun_chr_write_iter,
3315         .poll   = tun_chr_poll,
3316         .unlocked_ioctl = tun_chr_ioctl,
3317 #ifdef CONFIG_COMPAT
3318         .compat_ioctl = tun_chr_compat_ioctl,
3319 #endif
3320         .open   = tun_chr_open,
3321         .release = tun_chr_close,
3322         .fasync = tun_chr_fasync,
3323 #ifdef CONFIG_PROC_FS
3324         .show_fdinfo = tun_chr_show_fdinfo,
3325 #endif
3326 };
3327
3328 static struct miscdevice tun_miscdev = {
3329         .minor = TUN_MINOR,
3330         .name = "tun",
3331         .nodename = "net/tun",
3332         .fops = &tun_fops,
3333 };
3334
3335 /* ethtool interface */
3336
3337 static int tun_get_link_ksettings(struct net_device *dev,
3338                                   struct ethtool_link_ksettings *cmd)
3339 {
3340         ethtool_link_ksettings_zero_link_mode(cmd, supported);
3341         ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3342         cmd->base.speed         = SPEED_10;
3343         cmd->base.duplex        = DUPLEX_FULL;
3344         cmd->base.port          = PORT_TP;
3345         cmd->base.phy_address   = 0;
3346         cmd->base.autoneg       = AUTONEG_DISABLE;
3347         return 0;
3348 }
3349
3350 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3351 {
3352         struct tun_struct *tun = netdev_priv(dev);
3353
3354         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3355         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3356
3357         switch (tun->flags & TUN_TYPE_MASK) {
3358         case IFF_TUN:
3359                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3360                 break;
3361         case IFF_TAP:
3362                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3363                 break;
3364         }
3365 }
3366
3367 static u32 tun_get_msglevel(struct net_device *dev)
3368 {
3369 #ifdef TUN_DEBUG
3370         struct tun_struct *tun = netdev_priv(dev);
3371         return tun->debug;
3372 #else
3373         return -EOPNOTSUPP;
3374 #endif
3375 }
3376
3377 static void tun_set_msglevel(struct net_device *dev, u32 value)
3378 {
3379 #ifdef TUN_DEBUG
3380         struct tun_struct *tun = netdev_priv(dev);
3381         tun->debug = value;
3382 #endif
3383 }
3384
3385 static int tun_get_coalesce(struct net_device *dev,
3386                             struct ethtool_coalesce *ec)
3387 {
3388         struct tun_struct *tun = netdev_priv(dev);
3389
3390         ec->rx_max_coalesced_frames = tun->rx_batched;
3391
3392         return 0;
3393 }
3394
3395 static int tun_set_coalesce(struct net_device *dev,
3396                             struct ethtool_coalesce *ec)
3397 {
3398         struct tun_struct *tun = netdev_priv(dev);
3399
3400         if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3401                 tun->rx_batched = NAPI_POLL_WEIGHT;
3402         else
3403                 tun->rx_batched = ec->rx_max_coalesced_frames;
3404
3405         return 0;
3406 }
3407
3408 static const struct ethtool_ops tun_ethtool_ops = {
3409         .get_drvinfo    = tun_get_drvinfo,
3410         .get_msglevel   = tun_get_msglevel,
3411         .set_msglevel   = tun_set_msglevel,
3412         .get_link       = ethtool_op_get_link,
3413         .get_ts_info    = ethtool_op_get_ts_info,
3414         .get_coalesce   = tun_get_coalesce,
3415         .set_coalesce   = tun_set_coalesce,
3416         .get_link_ksettings = tun_get_link_ksettings,
3417 };
3418
3419 static int tun_queue_resize(struct tun_struct *tun)
3420 {
3421         struct net_device *dev = tun->dev;
3422         struct tun_file *tfile;
3423         struct ptr_ring **rings;
3424         int n = tun->numqueues + tun->numdisabled;
3425         int ret, i;
3426
3427         rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3428         if (!rings)
3429                 return -ENOMEM;
3430
3431         for (i = 0; i < tun->numqueues; i++) {
3432                 tfile = rtnl_dereference(tun->tfiles[i]);
3433                 rings[i] = &tfile->tx_ring;
3434         }
3435         list_for_each_entry(tfile, &tun->disabled, next)
3436                 rings[i++] = &tfile->tx_ring;
3437
3438         ret = ptr_ring_resize_multiple(rings, n,
3439                                        dev->tx_queue_len, GFP_KERNEL,
3440                                        tun_ptr_free);
3441
3442         kfree(rings);
3443         return ret;
3444 }
3445
3446 static int tun_device_event(struct notifier_block *unused,
3447                             unsigned long event, void *ptr)
3448 {
3449         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3450         struct tun_struct *tun = netdev_priv(dev);
3451
3452         if (dev->rtnl_link_ops != &tun_link_ops)
3453                 return NOTIFY_DONE;
3454
3455         switch (event) {
3456         case NETDEV_CHANGE_TX_QUEUE_LEN:
3457                 if (tun_queue_resize(tun))
3458                         return NOTIFY_BAD;
3459                 break;
3460         default:
3461                 break;
3462         }
3463
3464         return NOTIFY_DONE;
3465 }
3466
3467 static struct notifier_block tun_notifier_block __read_mostly = {
3468         .notifier_call  = tun_device_event,
3469 };
3470
3471 static int __init tun_init(void)
3472 {
3473         int ret = 0;
3474
3475         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3476
3477         ret = rtnl_link_register(&tun_link_ops);
3478         if (ret) {
3479                 pr_err("Can't register link_ops\n");
3480                 goto err_linkops;
3481         }
3482
3483         ret = misc_register(&tun_miscdev);
3484         if (ret) {
3485                 pr_err("Can't register misc device %d\n", TUN_MINOR);
3486                 goto err_misc;
3487         }
3488
3489         ret = register_netdevice_notifier(&tun_notifier_block);
3490         if (ret) {
3491                 pr_err("Can't register netdevice notifier\n");
3492                 goto err_notifier;
3493         }
3494
3495         return  0;
3496
3497 err_notifier:
3498         misc_deregister(&tun_miscdev);
3499 err_misc:
3500         rtnl_link_unregister(&tun_link_ops);
3501 err_linkops:
3502         return ret;
3503 }
3504
3505 static void tun_cleanup(void)
3506 {
3507         misc_deregister(&tun_miscdev);
3508         rtnl_link_unregister(&tun_link_ops);
3509         unregister_netdevice_notifier(&tun_notifier_block);
3510 }
3511
3512 /* Get an underlying socket object from tun file.  Returns error unless file is
3513  * attached to a device.  The returned object works like a packet socket, it
3514  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
3515  * holding a reference to the file for as long as the socket is in use. */
3516 struct socket *tun_get_socket(struct file *file)
3517 {
3518         struct tun_file *tfile;
3519         if (file->f_op != &tun_fops)
3520                 return ERR_PTR(-EINVAL);
3521         tfile = file->private_data;
3522         if (!tfile)
3523                 return ERR_PTR(-EBADFD);
3524         return &tfile->socket;
3525 }
3526 EXPORT_SYMBOL_GPL(tun_get_socket);
3527
3528 struct ptr_ring *tun_get_tx_ring(struct file *file)
3529 {
3530         struct tun_file *tfile;
3531
3532         if (file->f_op != &tun_fops)
3533                 return ERR_PTR(-EINVAL);
3534         tfile = file->private_data;
3535         if (!tfile)
3536                 return ERR_PTR(-EBADFD);
3537         return &tfile->tx_ring;
3538 }
3539 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3540
3541 module_init(tun_init);
3542 module_exit(tun_cleanup);
3543 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3544 MODULE_AUTHOR(DRV_COPYRIGHT);
3545 MODULE_LICENSE("GPL");
3546 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3547 MODULE_ALIAS("devname:net/tun");