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 static void tun_default_link_ksettings(struct net_device *dev,
  85                                        struct ethtool_link_ksettings *cmd);
  86
  87 /* Uncomment to enable debugging */
  88 /* #define TUN_DEBUG 1 */
  89
  90 #ifdef TUN_DEBUG
  91 static int debug;
  92
  93 #define tun_debug(level, tun, fmt, args...)                     \
  94 do {                                                            \
  95         if (tun->debug)                                         \
  96                 netdev_printk(level, tun->dev, fmt, ##args);    \
  97 } while (0)
  98 #define DBG1(level, fmt, args...)                               \
  99 do {                                                            \
 100         if (debug == 2)                                         \
 101                 printk(level fmt, ##args);                      \
 102 } while (0)
 103 #else
 104 #define tun_debug(level, tun, fmt, args...)                     \
 105 do {                                                            \
 106         if (0)                                                  \
 107                 netdev_printk(level, tun->dev, fmt, ##args);    \
 108 } while (0)
 109 #define DBG1(level, fmt, args...)                               \
 110 do {                                                            \
 111         if (0)                                                  \
 112                 printk(level fmt, ##args);                      \
 113 } while (0)
 114 #endif
 115
 116 #define TUN_HEADROOM 256
 117 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
 118
 119 /* TUN device flags */
 120
 121 /* IFF_ATTACH_QUEUE is never stored in device flags,
 122  * overload it to mean fasync when stored there.
 123  */
 124 #define TUN_FASYNC      IFF_ATTACH_QUEUE
 125 /* High bits in flags field are unused. */
 126 #define TUN_VNET_LE     0x80000000
 127 #define TUN_VNET_BE     0x40000000
 128
 129 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
 130                       IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
 131
 132 #define GOODCOPY_LEN 128
 133
 134 #define FLT_EXACT_COUNT 8
 135 struct tap_filter {
 136         unsigned int    count;    /* Number of addrs. Zero means disabled */
 137         u32             mask[2];  /* Mask of the hashed addrs */
 138         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 139 };
 140
 141 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
 142  * to max number of VCPUs in guest. */
 143 #define MAX_TAP_QUEUES 256
 144 #define MAX_TAP_FLOWS  4096
 145
 146 #define TUN_FLOW_EXPIRE (3 * HZ)
 147
 148 struct tun_pcpu_stats {
 149         u64 rx_packets;
 150         u64 rx_bytes;
 151         u64 tx_packets;
 152         u64 tx_bytes;
 153         struct u64_stats_sync syncp;
 154         u32 rx_dropped;
 155         u32 tx_dropped;
 156         u32 rx_frame_errors;
 157 };
 158
 159 /* A tun_file connects an open character device to a tuntap netdevice. It
 160  * also contains all socket related structures (except sock_fprog and tap_filter)
 161  * to serve as one transmit queue for tuntap device. The sock_fprog and
 162  * tap_filter were kept in tun_struct since they were used for filtering for the
 163  * netdevice not for a specific queue (at least I didn't see the requirement for
 164  * this).
 165  *
 166  * RCU usage:
 167  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
 168  * other can only be read while rcu_read_lock or rtnl_lock is held.
 169  */
 170 struct tun_file {
 171         struct sock sk;
 172         struct socket socket;
 173         struct socket_wq wq;
 174         struct tun_struct __rcu *tun;
 175         struct fasync_struct *fasync;
 176         /* only used for fasnyc */
 177         unsigned int flags;
 178         union {
 179                 u16 queue_index;
 180                 unsigned int ifindex;
 181         };
 182         struct napi_struct napi;
 183         bool napi_enabled;
 184         bool napi_frags_enabled;
 185         struct mutex napi_mutex;        /* Protects access to the above napi */
 186         struct list_head next;
 187         struct tun_struct *detached;
 188         struct ptr_ring tx_ring;
 189         struct xdp_rxq_info xdp_rxq;
 190 };
 191
 192 struct tun_flow_entry {
 193         struct hlist_node hash_link;
 194         struct rcu_head rcu;
 195         struct tun_struct *tun;
 196
 197         u32 rxhash;
 198         u32 rps_rxhash;
 199         int queue_index;
 200         unsigned long updated;
 201 };
 202
 203 #define TUN_NUM_FLOW_ENTRIES 1024
 204 #define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
 205
 206 struct tun_prog {
 207         struct rcu_head rcu;
 208         struct bpf_prog *prog;
 209 };
 210
 211 /* Since the socket were moved to tun_file, to preserve the behavior of persist
 212  * device, socket filter, sndbuf and vnet header size were restore when the
 213  * file were attached to a persist device.
 214  */
 215 struct tun_struct {
 216         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
 217         unsigned int            numqueues;
 218         unsigned int            flags;
 219         kuid_t                  owner;
 220         kgid_t                  group;
 221
 222         struct net_device       *dev;
 223         netdev_features_t       set_features;
 224 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 225                           NETIF_F_TSO6)
 226
 227         int                     align;
 228         int                     vnet_hdr_sz;
 229         int                     sndbuf;
 230         struct tap_filter       txflt;
 231         struct sock_fprog       fprog;
 232         /* protected by rtnl lock */
 233         bool                    filter_attached;
 234 #ifdef TUN_DEBUG
 235         int debug;
 236 #endif
 237         spinlock_t lock;
 238         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 239         struct timer_list flow_gc_timer;
 240         unsigned long ageing_time;
 241         unsigned int numdisabled;
 242         struct list_head disabled;
 243         void *security;
 244         u32 flow_count;
 245         u32 rx_batched;
 246         struct tun_pcpu_stats __percpu *pcpu_stats;
 247         struct bpf_prog __rcu *xdp_prog;
 248         struct tun_prog __rcu *steering_prog;
 249         struct tun_prog __rcu *filter_prog;
 250         struct ethtool_link_ksettings link_ksettings;
 251 };
 252
 253 struct veth {
 254         __be16 h_vlan_proto;
 255         __be16 h_vlan_TCI;
 256 };
 257
 258 bool tun_is_xdp_frame(void *ptr)
 259 {
 260         return (unsigned long)ptr & TUN_XDP_FLAG;
 261 }
 262 EXPORT_SYMBOL(tun_is_xdp_frame);
 263
 264 void *tun_xdp_to_ptr(void *ptr)
 265 {
 266         return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
 267 }
 268 EXPORT_SYMBOL(tun_xdp_to_ptr);
 269
 270 void *tun_ptr_to_xdp(void *ptr)
 271 {
 272         return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
 273 }
 274 EXPORT_SYMBOL(tun_ptr_to_xdp);
 275
 276 static int tun_napi_receive(struct napi_struct *napi, int budget)
 277 {
 278         struct tun_file *tfile = container_of(napi, struct tun_file, napi);
 279         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
 280         struct sk_buff_head process_queue;
 281         struct sk_buff *skb;
 282         int received = 0;
 283
 284         __skb_queue_head_init(&process_queue);
 285
 286         spin_lock(&queue->lock);
 287         skb_queue_splice_tail_init(queue, &process_queue);
 288         spin_unlock(&queue->lock);
 289
 290         while (received < budget && (skb = __skb_dequeue(&process_queue))) {
 291                 napi_gro_receive(napi, skb);
 292                 ++received;
 293         }
 294
 295         if (!skb_queue_empty(&process_queue)) {
 296                 spin_lock(&queue->lock);
 297                 skb_queue_splice(&process_queue, queue);
 298                 spin_unlock(&queue->lock);
 299         }
 300
 301         return received;
 302 }
 303
 304 static int tun_napi_poll(struct napi_struct *napi, int budget)
 305 {
 306         unsigned int received;
 307
 308         received = tun_napi_receive(napi, budget);
 309
 310         if (received < budget)
 311                 napi_complete_done(napi, received);
 312
 313         return received;
 314 }
 315
 316 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
 317                           bool napi_en, bool napi_frags)
 318 {
 319         tfile->napi_enabled = napi_en;
 320         tfile->napi_frags_enabled = napi_en && napi_frags;
 321         if (napi_en) {
 322                 netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
 323                                NAPI_POLL_WEIGHT);
 324                 napi_enable(&tfile->napi);
 325         }
 326 }
 327
 328 static void tun_napi_disable(struct tun_file *tfile)
 329 {
 330         if (tfile->napi_enabled)
 331                 napi_disable(&tfile->napi);
 332 }
 333
 334 static void tun_napi_del(struct tun_file *tfile)
 335 {
 336         if (tfile->napi_enabled)
 337                 netif_napi_del(&tfile->napi);
 338 }
 339
 340 static bool tun_napi_frags_enabled(const struct tun_file *tfile)
 341 {
 342         return tfile->napi_frags_enabled;
 343 }
 344
 345 #ifdef CONFIG_TUN_VNET_CROSS_LE
 346 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 347 {
 348         return tun->flags & TUN_VNET_BE ? false :
 349                 virtio_legacy_is_little_endian();
 350 }
 351
 352 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 353 {
 354         int be = !!(tun->flags & TUN_VNET_BE);
 355
 356         if (put_user(be, argp))
 357                 return -EFAULT;
 358
 359         return 0;
 360 }
 361
 362 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 363 {
 364         int be;
 365
 366         if (get_user(be, argp))
 367                 return -EFAULT;
 368
 369         if (be)
 370                 tun->flags |= TUN_VNET_BE;
 371         else
 372                 tun->flags &= ~TUN_VNET_BE;
 373
 374         return 0;
 375 }
 376 #else
 377 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 378 {
 379         return virtio_legacy_is_little_endian();
 380 }
 381
 382 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 383 {
 384         return -EINVAL;
 385 }
 386
 387 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 388 {
 389         return -EINVAL;
 390 }
 391 #endif /* CONFIG_TUN_VNET_CROSS_LE */
 392
 393 static inline bool tun_is_little_endian(struct tun_struct *tun)
 394 {
 395         return tun->flags & TUN_VNET_LE ||
 396                 tun_legacy_is_little_endian(tun);
 397 }
 398
 399 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
 400 {
 401         return __virtio16_to_cpu(tun_is_little_endian(tun), val);
 402 }
 403
 404 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
 405 {
 406         return __cpu_to_virtio16(tun_is_little_endian(tun), val);
 407 }
 408
 409 static inline u32 tun_hashfn(u32 rxhash)
 410 {
 411         return rxhash & TUN_MASK_FLOW_ENTRIES;
 412 }
 413
 414 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 415 {
 416         struct tun_flow_entry *e;
 417
 418         hlist_for_each_entry_rcu(e, head, hash_link) {
 419                 if (e->rxhash == rxhash)
 420                         return e;
 421         }
 422         return NULL;
 423 }
 424
 425 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 426                                               struct hlist_head *head,
 427                                               u32 rxhash, u16 queue_index)
 428 {
 429         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 430
 431         if (e) {
 432                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 433                           rxhash, queue_index);
 434                 e->updated = jiffies;
 435                 e->rxhash = rxhash;
 436                 e->rps_rxhash = 0;
 437                 e->queue_index = queue_index;
 438                 e->tun = tun;
 439                 hlist_add_head_rcu(&e->hash_link, head);
 440                 ++tun->flow_count;
 441         }
 442         return e;
 443 }
 444
 445 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 446 {
 447         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 448                   e->rxhash, e->queue_index);
 449         hlist_del_rcu(&e->hash_link);
 450         kfree_rcu(e, rcu);
 451         --tun->flow_count;
 452 }
 453
 454 static void tun_flow_flush(struct tun_struct *tun)
 455 {
 456         int i;
 457
 458         spin_lock_bh(&tun->lock);
 459         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 460                 struct tun_flow_entry *e;
 461                 struct hlist_node *n;
 462
 463                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 464                         tun_flow_delete(tun, e);
 465         }
 466         spin_unlock_bh(&tun->lock);
 467 }
 468
 469 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 470 {
 471         int i;
 472
 473         spin_lock_bh(&tun->lock);
 474         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 475                 struct tun_flow_entry *e;
 476                 struct hlist_node *n;
 477
 478                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 479                         if (e->queue_index == queue_index)
 480                                 tun_flow_delete(tun, e);
 481                 }
 482         }
 483         spin_unlock_bh(&tun->lock);
 484 }
 485
 486 static void tun_flow_cleanup(struct timer_list *t)
 487 {
 488         struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
 489         unsigned long delay = tun->ageing_time;
 490         unsigned long next_timer = jiffies + delay;
 491         unsigned long count = 0;
 492         int i;
 493
 494         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 495
 496         spin_lock(&tun->lock);
 497         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 498                 struct tun_flow_entry *e;
 499                 struct hlist_node *n;
 500
 501                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 502                         unsigned long this_timer;
 503
 504                         this_timer = e->updated + delay;
 505                         if (time_before_eq(this_timer, jiffies)) {
 506                                 tun_flow_delete(tun, e);
 507                                 continue;
 508                         }
 509                         count++;
 510                         if (time_before(this_timer, next_timer))
 511                                 next_timer = this_timer;
 512                 }
 513         }
 514
 515         if (count)
 516                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 517         spin_unlock(&tun->lock);
 518 }
 519
 520 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 521                             struct tun_file *tfile)
 522 {
 523         struct hlist_head *head;
 524         struct tun_flow_entry *e;
 525         unsigned long delay = tun->ageing_time;
 526         u16 queue_index = tfile->queue_index;
 527
 528         if (!rxhash)
 529                 return;
 530         else
 531                 head = &tun->flows[tun_hashfn(rxhash)];
 532
 533         rcu_read_lock();
 534
 535         e = tun_flow_find(head, rxhash);
 536         if (likely(e)) {
 537                 /* TODO: keep queueing to old queue until it's empty? */
 538                 e->queue_index = queue_index;
 539                 e->updated = jiffies;
 540                 sock_rps_record_flow_hash(e->rps_rxhash);
 541         } else {
 542                 spin_lock_bh(&tun->lock);
 543                 if (!tun_flow_find(head, rxhash) &&
 544                     tun->flow_count < MAX_TAP_FLOWS)
 545                         tun_flow_create(tun, head, rxhash, queue_index);
 546
 547                 if (!timer_pending(&tun->flow_gc_timer))
 548                         mod_timer(&tun->flow_gc_timer,
 549                                   round_jiffies_up(jiffies + delay));
 550                 spin_unlock_bh(&tun->lock);
 551         }
 552
 553         rcu_read_unlock();
 554 }
 555
 556 /**
 557  * Save the hash received in the stack receive path and update the
 558  * flow_hash table accordingly.
 559  */
 560 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
 561 {
 562         if (unlikely(e->rps_rxhash != hash))
 563                 e->rps_rxhash = hash;
 564 }
 565
 566 /* We try to identify a flow through its rxhash first. The reason that
 567  * we do not check rxq no. is because some cards(e.g 82599), chooses
 568  * the rxq based on the txq where the last packet of the flow comes. As
 569  * the userspace application move between processors, we may get a
 570  * different rxq no. here. If we could not get rxhash, then we would
 571  * hope the rxq no. may help here.
 572  */
 573 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 574 {
 575         struct tun_flow_entry *e;
 576         u32 txq = 0;
 577         u32 numqueues = 0;
 578
 579         numqueues = READ_ONCE(tun->numqueues);
 580
 581         txq = __skb_get_hash_symmetric(skb);
 582         if (txq) {
 583                 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 584                 if (e) {
 585                         tun_flow_save_rps_rxhash(e, txq);
 586                         txq = e->queue_index;
 587                 } else
 588                         /* use multiply and shift instead of expensive divide */
 589                         txq = ((u64)txq * numqueues) >> 32;
 590         } else if (likely(skb_rx_queue_recorded(skb))) {
 591                 txq = skb_get_rx_queue(skb);
 592                 while (unlikely(txq >= numqueues))
 593                         txq -= numqueues;
 594         }
 595
 596         return txq;
 597 }
 598
 599 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 600 {
 601         struct tun_prog *prog;
 602         u16 ret = 0;
 603
 604         prog = rcu_dereference(tun->steering_prog);
 605         if (prog)
 606                 ret = bpf_prog_run_clear_cb(prog->prog, skb);
 607
 608         return ret % tun->numqueues;
 609 }
 610
 611 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
 612                             struct net_device *sb_dev,
 613                             select_queue_fallback_t fallback)
 614 {
 615         struct tun_struct *tun = netdev_priv(dev);
 616         u16 ret;
 617
 618         rcu_read_lock();
 619         if (rcu_dereference(tun->steering_prog))
 620                 ret = tun_ebpf_select_queue(tun, skb);
 621         else
 622                 ret = tun_automq_select_queue(tun, skb);
 623         rcu_read_unlock();
 624
 625         return ret;
 626 }
 627
 628 static inline bool tun_not_capable(struct tun_struct *tun)
 629 {
 630         const struct cred *cred = current_cred();
 631         struct net *net = dev_net(tun->dev);
 632
 633         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 634                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 635                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 636 }
 637
 638 static void tun_set_real_num_queues(struct tun_struct *tun)
 639 {
 640         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 641         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 642 }
 643
 644 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 645 {
 646         tfile->detached = tun;
 647         list_add_tail(&tfile->next, &tun->disabled);
 648         ++tun->numdisabled;
 649 }
 650
 651 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 652 {
 653         struct tun_struct *tun = tfile->detached;
 654
 655         tfile->detached = NULL;
 656         list_del_init(&tfile->next);
 657         --tun->numdisabled;
 658         return tun;
 659 }
 660
 661 void tun_ptr_free(void *ptr)
 662 {
 663         if (!ptr)
 664                 return;
 665         if (tun_is_xdp_frame(ptr)) {
 666                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
 667
 668                 xdp_return_frame(xdpf);
 669         } else {
 670                 __skb_array_destroy_skb(ptr);
 671         }
 672 }
 673 EXPORT_SYMBOL_GPL(tun_ptr_free);
 674
 675 static void tun_queue_purge(struct tun_file *tfile)
 676 {
 677         void *ptr;
 678
 679         while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
 680                 tun_ptr_free(ptr);
 681
 682         skb_queue_purge(&tfile->sk.sk_write_queue);
 683         skb_queue_purge(&tfile->sk.sk_error_queue);
 684 }
 685
 686 static void __tun_detach(struct tun_file *tfile, bool clean)
 687 {
 688         struct tun_file *ntfile;
 689         struct tun_struct *tun;
 690
 691         tun = rtnl_dereference(tfile->tun);
 692
 693         if (tun && clean) {
 694                 tun_napi_disable(tfile);
 695                 tun_napi_del(tfile);
 696         }
 697
 698         if (tun && !tfile->detached) {
 699                 u16 index = tfile->queue_index;
 700                 BUG_ON(index >= tun->numqueues);
 701
 702                 rcu_assign_pointer(tun->tfiles[index],
 703                                    tun->tfiles[tun->numqueues - 1]);
 704                 ntfile = rtnl_dereference(tun->tfiles[index]);
 705                 ntfile->queue_index = index;
 706
 707                 --tun->numqueues;
 708                 if (clean) {
 709                         RCU_INIT_POINTER(tfile->tun, NULL);
 710                         sock_put(&tfile->sk);
 711                 } else
 712                         tun_disable_queue(tun, tfile);
 713
 714                 synchronize_net();
 715                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 716                 /* Drop read queue */
 717                 tun_queue_purge(tfile);
 718                 tun_set_real_num_queues(tun);
 719         } else if (tfile->detached && clean) {
 720                 tun = tun_enable_queue(tfile);
 721                 sock_put(&tfile->sk);
 722         }
 723
 724         if (clean) {
 725                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 726                         netif_carrier_off(tun->dev);
 727
 728                         if (!(tun->flags & IFF_PERSIST) &&
 729                             tun->dev->reg_state == NETREG_REGISTERED)
 730                                 unregister_netdevice(tun->dev);
 731                 }
 732                 if (tun)
 733                         xdp_rxq_info_unreg(&tfile->xdp_rxq);
 734                 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
 735                 sock_put(&tfile->sk);
 736         }
 737 }
 738
 739 static void tun_detach(struct tun_file *tfile, bool clean)
 740 {
 741         struct tun_struct *tun;
 742         struct net_device *dev;
 743
 744         rtnl_lock();
 745         tun = rtnl_dereference(tfile->tun);
 746         dev = tun ? tun->dev : NULL;
 747         __tun_detach(tfile, clean);
 748         if (dev)
 749                 netdev_state_change(dev);
 750         rtnl_unlock();
 751 }
 752
 753 static void tun_detach_all(struct net_device *dev)
 754 {
 755         struct tun_struct *tun = netdev_priv(dev);
 756         struct tun_file *tfile, *tmp;
 757         int i, n = tun->numqueues;
 758
 759         for (i = 0; i < n; i++) {
 760                 tfile = rtnl_dereference(tun->tfiles[i]);
 761                 BUG_ON(!tfile);
 762                 tun_napi_disable(tfile);
 763                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 764                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 765                 RCU_INIT_POINTER(tfile->tun, NULL);
 766                 --tun->numqueues;
 767         }
 768         list_for_each_entry(tfile, &tun->disabled, next) {
 769                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 770                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 771                 RCU_INIT_POINTER(tfile->tun, NULL);
 772         }
 773         BUG_ON(tun->numqueues != 0);
 774
 775         synchronize_net();
 776         for (i = 0; i < n; i++) {
 777                 tfile = rtnl_dereference(tun->tfiles[i]);
 778                 tun_napi_del(tfile);
 779                 /* Drop read queue */
 780                 tun_queue_purge(tfile);
 781                 xdp_rxq_info_unreg(&tfile->xdp_rxq);
 782                 sock_put(&tfile->sk);
 783         }
 784         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 785                 tun_enable_queue(tfile);
 786                 tun_queue_purge(tfile);
 787                 xdp_rxq_info_unreg(&tfile->xdp_rxq);
 788                 sock_put(&tfile->sk);
 789         }
 790         BUG_ON(tun->numdisabled != 0);
 791
 792         if (tun->flags & IFF_PERSIST)
 793                 module_put(THIS_MODULE);
 794 }
 795
 796 static int tun_attach(struct tun_struct *tun, struct file *file,
 797                       bool skip_filter, bool napi, bool napi_frags)
 798 {
 799         struct tun_file *tfile = file->private_data;
 800         struct net_device *dev = tun->dev;
 801         int err;
 802
 803         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 804         if (err < 0)
 805                 goto out;
 806
 807         err = -EINVAL;
 808         if (rtnl_dereference(tfile->tun) && !tfile->detached)
 809                 goto out;
 810
 811         err = -EBUSY;
 812         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
 813                 goto out;
 814
 815         err = -E2BIG;
 816         if (!tfile->detached &&
 817             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 818                 goto out;
 819
 820         err = 0;
 821
 822         /* Re-attach the filter to persist device */
 823         if (!skip_filter && (tun->filter_attached == true)) {
 824                 lock_sock(tfile->socket.sk);
 825                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 826                 release_sock(tfile->socket.sk);
 827                 if (!err)
 828                         goto out;
 829         }
 830
 831         if (!tfile->detached &&
 832             ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
 833                             GFP_KERNEL, tun_ptr_free)) {
 834                 err = -ENOMEM;
 835                 goto out;
 836         }
 837
 838         tfile->queue_index = tun->numqueues;
 839         tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
 840
 841         if (tfile->detached) {
 842                 /* Re-attach detached tfile, updating XDP queue_index */
 843                 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
 844
 845                 if (tfile->xdp_rxq.queue_index    != tfile->queue_index)
 846                         tfile->xdp_rxq.queue_index = tfile->queue_index;
 847         } else {
 848                 /* Setup XDP RX-queue info, for new tfile getting attached */
 849                 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
 850                                        tun->dev, tfile->queue_index);
 851                 if (err < 0)
 852                         goto out;
 853                 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
 854                                                  MEM_TYPE_PAGE_SHARED, NULL);
 855                 if (err < 0) {
 856                         xdp_rxq_info_unreg(&tfile->xdp_rxq);
 857                         goto out;
 858                 }
 859                 err = 0;
 860         }
 861
 862         rcu_assign_pointer(tfile->tun, tun);
 863         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 864         tun->numqueues++;
 865
 866         if (tfile->detached) {
 867                 tun_enable_queue(tfile);
 868         } else {
 869                 sock_hold(&tfile->sk);
 870                 tun_napi_init(tun, tfile, napi, napi_frags);
 871         }
 872
 873         tun_set_real_num_queues(tun);
 874
 875         /* device is allowed to go away first, so no need to hold extra
 876          * refcnt.
 877          */
 878
 879 out:
 880         return err;
 881 }
 882
 883 static struct tun_struct *tun_get(struct tun_file *tfile)
 884 {
 885         struct tun_struct *tun;
 886
 887         rcu_read_lock();
 888         tun = rcu_dereference(tfile->tun);
 889         if (tun)
 890                 dev_hold(tun->dev);
 891         rcu_read_unlock();
 892
 893         return tun;
 894 }
 895
 896 static void tun_put(struct tun_struct *tun)
 897 {
 898         dev_put(tun->dev);
 899 }
 900
 901 /* TAP filtering */
 902 static void addr_hash_set(u32 *mask, const u8 *addr)
 903 {
 904         int n = ether_crc(ETH_ALEN, addr) >> 26;
 905         mask[n >> 5] |= (1 << (n & 31));
 906 }
 907
 908 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 909 {
 910         int n = ether_crc(ETH_ALEN, addr) >> 26;
 911         return mask[n >> 5] & (1 << (n & 31));
 912 }
 913
 914 static int update_filter(struct tap_filter *filter, void __user *arg)
 915 {
 916         struct { u8 u[ETH_ALEN]; } *addr;
 917         struct tun_filter uf;
 918         int err, alen, n, nexact;
 919
 920         if (copy_from_user(&uf, arg, sizeof(uf)))
 921                 return -EFAULT;
 922
 923         if (!uf.count) {
 924                 /* Disabled */
 925                 filter->count = 0;
 926                 return 0;
 927         }
 928
 929         alen = ETH_ALEN * uf.count;
 930         addr = memdup_user(arg + sizeof(uf), alen);
 931         if (IS_ERR(addr))
 932                 return PTR_ERR(addr);
 933
 934         /* The filter is updated without holding any locks. Which is
 935          * perfectly safe. We disable it first and in the worst
 936          * case we'll accept a few undesired packets. */
 937         filter->count = 0;
 938         wmb();
 939
 940         /* Use first set of addresses as an exact filter */
 941         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 942                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 943
 944         nexact = n;
 945
 946         /* Remaining multicast addresses are hashed,
 947          * unicast will leave the filter disabled. */
 948         memset(filter->mask, 0, sizeof(filter->mask));
 949         for (; n < uf.count; n++) {
 950                 if (!is_multicast_ether_addr(addr[n].u)) {
 951                         err = 0; /* no filter */
 952                         goto free_addr;
 953                 }
 954                 addr_hash_set(filter->mask, addr[n].u);
 955         }
 956
 957         /* For ALLMULTI just set the mask to all ones.
 958          * This overrides the mask populated above. */
 959         if ((uf.flags & TUN_FLT_ALLMULTI))
 960                 memset(filter->mask, ~0, sizeof(filter->mask));
 961
 962         /* Now enable the filter */
 963         wmb();
 964         filter->count = nexact;
 965
 966         /* Return the number of exact filters */
 967         err = nexact;
 968 free_addr:
 969         kfree(addr);
 970         return err;
 971 }
 972
 973 /* Returns: 0 - drop, !=0 - accept */
 974 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 975 {
 976         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 977          * at this point. */
 978         struct ethhdr *eh = (struct ethhdr *) skb->data;
 979         int i;
 980
 981         /* Exact match */
 982         for (i = 0; i < filter->count; i++)
 983                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 984                         return 1;
 985
 986         /* Inexact match (multicast only) */
 987         if (is_multicast_ether_addr(eh->h_dest))
 988                 return addr_hash_test(filter->mask, eh->h_dest);
 989
 990         return 0;
 991 }
 992
 993 /*
 994  * Checks whether the packet is accepted or not.
 995  * Returns: 0 - drop, !=0 - accept
 996  */
 997 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 998 {
 999         if (!filter->count)
1000                 return 1;
1001
1002         return run_filter(filter, skb);
1003 }
1004
1005 /* Network device part of the driver */
1006
1007 static const struct ethtool_ops tun_ethtool_ops;
1008
1009 /* Net device detach from fd. */
1010 static void tun_net_uninit(struct net_device *dev)
1011 {
1012         tun_detach_all(dev);
1013 }
1014
1015 /* Net device open. */
1016 static int tun_net_open(struct net_device *dev)
1017 {
1018         struct tun_struct *tun = netdev_priv(dev);
1019         int i;
1020
1021         netif_tx_start_all_queues(dev);
1022
1023         for (i = 0; i < tun->numqueues; i++) {
1024                 struct tun_file *tfile;
1025
1026                 tfile = rtnl_dereference(tun->tfiles[i]);
1027                 tfile->socket.sk->sk_write_space(tfile->socket.sk);
1028         }
1029
1030         return 0;
1031 }
1032
1033 /* Net device close. */
1034 static int tun_net_close(struct net_device *dev)
1035 {
1036         netif_tx_stop_all_queues(dev);
1037         return 0;
1038 }
1039
1040 /* Net device start xmit */
1041 static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1042 {
1043 #ifdef CONFIG_RPS
1044         if (tun->numqueues == 1 && static_key_false(&rps_needed)) {
1045                 /* Select queue was not called for the skbuff, so we extract the
1046                  * RPS hash and save it into the flow_table here.
1047                  */
1048                 __u32 rxhash;
1049
1050                 rxhash = __skb_get_hash_symmetric(skb);
1051                 if (rxhash) {
1052                         struct tun_flow_entry *e;
1053                         e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
1054                                         rxhash);
1055                         if (e)
1056                                 tun_flow_save_rps_rxhash(e, rxhash);
1057                 }
1058         }
1059 #endif
1060 }
1061
1062 static unsigned int run_ebpf_filter(struct tun_struct *tun,
1063                                     struct sk_buff *skb,
1064                                     int len)
1065 {
1066         struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1067
1068         if (prog)
1069                 len = bpf_prog_run_clear_cb(prog->prog, skb);
1070
1071         return len;
1072 }
1073
1074 /* Net device start xmit */
1075 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1076 {
1077         struct tun_struct *tun = netdev_priv(dev);
1078         int txq = skb->queue_mapping;
1079         struct tun_file *tfile;
1080         int len = skb->len;
1081
1082         rcu_read_lock();
1083         tfile = rcu_dereference(tun->tfiles[txq]);
1084
1085         /* Drop packet if interface is not attached */
1086         if (txq >= tun->numqueues)
1087                 goto drop;
1088
1089         if (!rcu_dereference(tun->steering_prog))
1090                 tun_automq_xmit(tun, skb);
1091
1092         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
1093
1094         BUG_ON(!tfile);
1095
1096         /* Drop if the filter does not like it.
1097          * This is a noop if the filter is disabled.
1098          * Filter can be enabled only for the TAP devices. */
1099         if (!check_filter(&tun->txflt, skb))
1100                 goto drop;
1101
1102         if (tfile->socket.sk->sk_filter &&
1103             sk_filter(tfile->socket.sk, skb))
1104                 goto drop;
1105
1106         len = run_ebpf_filter(tun, skb, len);
1107         if (len == 0 || pskb_trim(skb, len))
1108                 goto drop;
1109
1110         if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1111                 goto drop;
1112
1113         skb_tx_timestamp(skb);
1114
1115         /* Orphan the skb - required as we might hang on to it
1116          * for indefinite time.
1117          */
1118         skb_orphan(skb);
1119
1120         nf_reset(skb);
1121
1122         if (ptr_ring_produce(&tfile->tx_ring, skb))
1123                 goto drop;
1124
1125         /* Notify and wake up reader process */
1126         if (tfile->flags & TUN_FASYNC)
1127                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1128         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1129
1130         rcu_read_unlock();
1131         return NETDEV_TX_OK;
1132
1133 drop:
1134         this_cpu_inc(tun->pcpu_stats->tx_dropped);
1135         skb_tx_error(skb);
1136         kfree_skb(skb);
1137         rcu_read_unlock();
1138         return NET_XMIT_DROP;
1139 }
1140
1141 static void tun_net_mclist(struct net_device *dev)
1142 {
1143         /*
1144          * This callback is supposed to deal with mc filter in
1145          * _rx_ path and has nothing to do with the _tx_ path.
1146          * In rx path we always accept everything userspace gives us.
1147          */
1148 }
1149
1150 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1151         netdev_features_t features)
1152 {
1153         struct tun_struct *tun = netdev_priv(dev);
1154
1155         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1156 }
1157
1158 static void tun_set_headroom(struct net_device *dev, int new_hr)
1159 {
1160         struct tun_struct *tun = netdev_priv(dev);
1161
1162         if (new_hr < NET_SKB_PAD)
1163                 new_hr = NET_SKB_PAD;
1164
1165         tun->align = new_hr;
1166 }
1167
1168 static void
1169 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1170 {
1171         u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1172         struct tun_struct *tun = netdev_priv(dev);
1173         struct tun_pcpu_stats *p;
1174         int i;
1175
1176         for_each_possible_cpu(i) {
1177                 u64 rxpackets, rxbytes, txpackets, txbytes;
1178                 unsigned int start;
1179
1180                 p = per_cpu_ptr(tun->pcpu_stats, i);
1181                 do {
1182                         start = u64_stats_fetch_begin(&p->syncp);
1183                         rxpackets       = p->rx_packets;
1184                         rxbytes         = p->rx_bytes;
1185                         txpackets       = p->tx_packets;
1186                         txbytes         = p->tx_bytes;
1187                 } while (u64_stats_fetch_retry(&p->syncp, start));
1188
1189                 stats->rx_packets       += rxpackets;
1190                 stats->rx_bytes         += rxbytes;
1191                 stats->tx_packets       += txpackets;
1192                 stats->tx_bytes         += txbytes;
1193
1194                 /* u32 counters */
1195                 rx_dropped      += p->rx_dropped;
1196                 rx_frame_errors += p->rx_frame_errors;
1197                 tx_dropped      += p->tx_dropped;
1198         }
1199         stats->rx_dropped  = rx_dropped;
1200         stats->rx_frame_errors = rx_frame_errors;
1201         stats->tx_dropped = tx_dropped;
1202 }
1203
1204 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1205                        struct netlink_ext_ack *extack)
1206 {
1207         struct tun_struct *tun = netdev_priv(dev);
1208         struct bpf_prog *old_prog;
1209
1210         old_prog = rtnl_dereference(tun->xdp_prog);
1211         rcu_assign_pointer(tun->xdp_prog, prog);
1212         if (old_prog)
1213                 bpf_prog_put(old_prog);
1214
1215         return 0;
1216 }
1217
1218 static u32 tun_xdp_query(struct net_device *dev)
1219 {
1220         struct tun_struct *tun = netdev_priv(dev);
1221         const struct bpf_prog *xdp_prog;
1222
1223         xdp_prog = rtnl_dereference(tun->xdp_prog);
1224         if (xdp_prog)
1225                 return xdp_prog->aux->id;
1226
1227         return 0;
1228 }
1229
1230 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1231 {
1232         switch (xdp->command) {
1233         case XDP_SETUP_PROG:
1234                 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1235         case XDP_QUERY_PROG:
1236                 xdp->prog_id = tun_xdp_query(dev);
1237                 return 0;
1238         default:
1239                 return -EINVAL;
1240         }
1241 }
1242
1243 static const struct net_device_ops tun_netdev_ops = {
1244         .ndo_uninit             = tun_net_uninit,
1245         .ndo_open               = tun_net_open,
1246         .ndo_stop               = tun_net_close,
1247         .ndo_start_xmit         = tun_net_xmit,
1248         .ndo_fix_features       = tun_net_fix_features,
1249         .ndo_select_queue       = tun_select_queue,
1250         .ndo_set_rx_headroom    = tun_set_headroom,
1251         .ndo_get_stats64        = tun_net_get_stats64,
1252 };
1253
1254 static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1255 {
1256         /* Notify and wake up reader process */
1257         if (tfile->flags & TUN_FASYNC)
1258                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1259         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1260 }
1261
1262 static int tun_xdp_xmit(struct net_device *dev, int n,
1263                         struct xdp_frame **frames, u32 flags)
1264 {
1265         struct tun_struct *tun = netdev_priv(dev);
1266         struct tun_file *tfile;
1267         u32 numqueues;
1268         int drops = 0;
1269         int cnt = n;
1270         int i;
1271
1272         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1273                 return -EINVAL;
1274
1275         rcu_read_lock();
1276
1277         numqueues = READ_ONCE(tun->numqueues);
1278         if (!numqueues) {
1279                 rcu_read_unlock();
1280                 return -ENXIO; /* Caller will free/return all frames */
1281         }
1282
1283         tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1284                                             numqueues]);
1285
1286         spin_lock(&tfile->tx_ring.producer_lock);
1287         for (i = 0; i < n; i++) {
1288                 struct xdp_frame *xdp = frames[i];
1289                 /* Encode the XDP flag into lowest bit for consumer to differ
1290                  * XDP buffer from sk_buff.
1291                  */
1292                 void *frame = tun_xdp_to_ptr(xdp);
1293
1294                 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1295                         this_cpu_inc(tun->pcpu_stats->tx_dropped);
1296                         xdp_return_frame_rx_napi(xdp);
1297                         drops++;
1298                 }
1299         }
1300         spin_unlock(&tfile->tx_ring.producer_lock);
1301
1302         if (flags & XDP_XMIT_FLUSH)
1303                 __tun_xdp_flush_tfile(tfile);
1304
1305         rcu_read_unlock();
1306         return cnt - drops;
1307 }
1308
1309 static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1310 {
1311         struct xdp_frame *frame = convert_to_xdp_frame(xdp);
1312
1313         if (unlikely(!frame))
1314                 return -EOVERFLOW;
1315
1316         return tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1317 }
1318
1319 static const struct net_device_ops tap_netdev_ops = {
1320         .ndo_uninit             = tun_net_uninit,
1321         .ndo_open               = tun_net_open,
1322         .ndo_stop               = tun_net_close,
1323         .ndo_start_xmit         = tun_net_xmit,
1324         .ndo_fix_features       = tun_net_fix_features,
1325         .ndo_set_rx_mode        = tun_net_mclist,
1326         .ndo_set_mac_address    = eth_mac_addr,
1327         .ndo_validate_addr      = eth_validate_addr,
1328         .ndo_select_queue       = tun_select_queue,
1329         .ndo_features_check     = passthru_features_check,
1330         .ndo_set_rx_headroom    = tun_set_headroom,
1331         .ndo_get_stats64        = tun_net_get_stats64,
1332         .ndo_bpf                = tun_xdp,
1333         .ndo_xdp_xmit           = tun_xdp_xmit,
1334 };
1335
1336 static void tun_flow_init(struct tun_struct *tun)
1337 {
1338         int i;
1339
1340         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1341                 INIT_HLIST_HEAD(&tun->flows[i]);
1342
1343         tun->ageing_time = TUN_FLOW_EXPIRE;
1344         timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1345         mod_timer(&tun->flow_gc_timer,
1346                   round_jiffies_up(jiffies + tun->ageing_time));
1347 }
1348
1349 static void tun_flow_uninit(struct tun_struct *tun)
1350 {
1351         del_timer_sync(&tun->flow_gc_timer);
1352         tun_flow_flush(tun);
1353 }
1354
1355 #define MIN_MTU 68
1356 #define MAX_MTU 65535
1357
1358 /* Initialize net device. */
1359 static void tun_net_init(struct net_device *dev)
1360 {
1361         struct tun_struct *tun = netdev_priv(dev);
1362
1363         switch (tun->flags & TUN_TYPE_MASK) {
1364         case IFF_TUN:
1365                 dev->netdev_ops = &tun_netdev_ops;
1366
1367                 /* Point-to-Point TUN Device */
1368                 dev->hard_header_len = 0;
1369                 dev->addr_len = 0;
1370                 dev->mtu = 1500;
1371
1372                 /* Zero header length */
1373                 dev->type = ARPHRD_NONE;
1374                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1375                 break;
1376
1377         case IFF_TAP:
1378                 dev->netdev_ops = &tap_netdev_ops;
1379                 /* Ethernet TAP Device */
1380                 ether_setup(dev);
1381                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1382                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1383
1384                 eth_hw_addr_random(dev);
1385
1386                 break;
1387         }
1388
1389         dev->min_mtu = MIN_MTU;
1390         dev->max_mtu = MAX_MTU - dev->hard_header_len;
1391 }
1392
1393 static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1394 {
1395         struct sock *sk = tfile->socket.sk;
1396
1397         return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1398 }
1399
1400 /* Character device part */
1401
1402 /* Poll */
1403 static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1404 {
1405         struct tun_file *tfile = file->private_data;
1406         struct tun_struct *tun = tun_get(tfile);
1407         struct sock *sk;
1408         __poll_t mask = 0;
1409
1410         if (!tun)
1411                 return EPOLLERR;
1412
1413         sk = tfile->socket.sk;
1414
1415         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1416
1417         poll_wait(file, sk_sleep(sk), wait);
1418
1419         if (!ptr_ring_empty(&tfile->tx_ring))
1420                 mask |= EPOLLIN | EPOLLRDNORM;
1421
1422         /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1423          * guarantee EPOLLOUT to be raised by either here or
1424          * tun_sock_write_space(). Then process could get notification
1425          * after it writes to a down device and meets -EIO.
1426          */
1427         if (tun_sock_writeable(tun, tfile) ||
1428             (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1429              tun_sock_writeable(tun, tfile)))
1430                 mask |= EPOLLOUT | EPOLLWRNORM;
1431
1432         if (tun->dev->reg_state != NETREG_REGISTERED)
1433                 mask = EPOLLERR;
1434
1435         tun_put(tun);
1436         return mask;
1437 }
1438
1439 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1440                                             size_t len,
1441                                             const struct iov_iter *it)
1442 {
1443         struct sk_buff *skb;
1444         size_t linear;
1445         int err;
1446         int i;
1447
1448         if (it->nr_segs > MAX_SKB_FRAGS + 1)
1449                 return ERR_PTR(-ENOMEM);
1450
1451         local_bh_disable();
1452         skb = napi_get_frags(&tfile->napi);
1453         local_bh_enable();
1454         if (!skb)
1455                 return ERR_PTR(-ENOMEM);
1456
1457         linear = iov_iter_single_seg_count(it);
1458         err = __skb_grow(skb, linear);
1459         if (err)
1460                 goto free;
1461
1462         skb->len = len;
1463         skb->data_len = len - linear;
1464         skb->truesize += skb->data_len;
1465
1466         for (i = 1; i < it->nr_segs; i++) {
1467                 struct page_frag *pfrag = &current->task_frag;
1468                 size_t fragsz = it->iov[i].iov_len;
1469
1470                 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1471                         err = -EINVAL;
1472                         goto free;
1473                 }
1474
1475                 if (!skb_page_frag_refill(fragsz, pfrag, GFP_KERNEL)) {
1476                         err = -ENOMEM;
1477                         goto free;
1478                 }
1479
1480                 skb_fill_page_desc(skb, i - 1, pfrag->page,
1481                                    pfrag->offset, fragsz);
1482                 page_ref_inc(pfrag->page);
1483                 pfrag->offset += fragsz;
1484         }
1485
1486         return skb;
1487 free:
1488         /* frees skb and all frags allocated with napi_alloc_frag() */
1489         napi_free_frags(&tfile->napi);
1490         return ERR_PTR(err);
1491 }
1492
1493 /* prepad is the amount to reserve at front.  len is length after that.
1494  * linear is a hint as to how much to copy (usually headers). */
1495 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1496                                      size_t prepad, size_t len,
1497                                      size_t linear, int noblock)
1498 {
1499         struct sock *sk = tfile->socket.sk;
1500         struct sk_buff *skb;
1501         int err;
1502
1503         /* Under a page?  Don't bother with paged skb. */
1504         if (prepad + len < PAGE_SIZE || !linear)
1505                 linear = len;
1506
1507         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1508                                    &err, 0);
1509         if (!skb)
1510                 return ERR_PTR(err);
1511
1512         skb_reserve(skb, prepad);
1513         skb_put(skb, linear);
1514         skb->data_len = len - linear;
1515         skb->len += len - linear;
1516
1517         return skb;
1518 }
1519
1520 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1521                            struct sk_buff *skb, int more)
1522 {
1523         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1524         struct sk_buff_head process_queue;
1525         u32 rx_batched = tun->rx_batched;
1526         bool rcv = false;
1527
1528         if (!rx_batched || (!more && skb_queue_empty(queue))) {
1529                 local_bh_disable();
1530                 netif_receive_skb(skb);
1531                 local_bh_enable();
1532                 return;
1533         }
1534
1535         spin_lock(&queue->lock);
1536         if (!more || skb_queue_len(queue) == rx_batched) {
1537                 __skb_queue_head_init(&process_queue);
1538                 skb_queue_splice_tail_init(queue, &process_queue);
1539                 rcv = true;
1540         } else {
1541                 __skb_queue_tail(queue, skb);
1542         }
1543         spin_unlock(&queue->lock);
1544
1545         if (rcv) {
1546                 struct sk_buff *nskb;
1547
1548                 local_bh_disable();
1549                 while ((nskb = __skb_dequeue(&process_queue)))
1550                         netif_receive_skb(nskb);
1551                 netif_receive_skb(skb);
1552                 local_bh_enable();
1553         }
1554 }
1555
1556 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1557                               int len, int noblock, bool zerocopy)
1558 {
1559         if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1560                 return false;
1561
1562         if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1563                 return false;
1564
1565         if (!noblock)
1566                 return false;
1567
1568         if (zerocopy)
1569                 return false;
1570
1571         if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1572             SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1573                 return false;
1574
1575         return true;
1576 }
1577
1578 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1579                                      struct tun_file *tfile,
1580                                      struct iov_iter *from,
1581                                      struct virtio_net_hdr *hdr,
1582                                      int len, int *skb_xdp)
1583 {
1584         struct page_frag *alloc_frag = &current->task_frag;
1585         struct sk_buff *skb;
1586         struct bpf_prog *xdp_prog;
1587         int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1588         unsigned int delta = 0;
1589         char *buf;
1590         size_t copied;
1591         int err, pad = TUN_RX_PAD;
1592
1593         rcu_read_lock();
1594         xdp_prog = rcu_dereference(tun->xdp_prog);
1595         if (xdp_prog)
1596                 pad += TUN_HEADROOM;
1597         buflen += SKB_DATA_ALIGN(len + pad);
1598         rcu_read_unlock();
1599
1600         alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1601         if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1602                 return ERR_PTR(-ENOMEM);
1603
1604         buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1605         copied = copy_page_from_iter(alloc_frag->page,
1606                                      alloc_frag->offset + pad,
1607                                      len, from);
1608         if (copied != len)
1609                 return ERR_PTR(-EFAULT);
1610
1611         /* There's a small window that XDP may be set after the check
1612          * of xdp_prog above, this should be rare and for simplicity
1613          * we do XDP on skb in case the headroom is not enough.
1614          */
1615         if (hdr->gso_type || !xdp_prog)
1616                 *skb_xdp = 1;
1617         else
1618                 *skb_xdp = 0;
1619
1620         local_bh_disable();
1621         rcu_read_lock();
1622         xdp_prog = rcu_dereference(tun->xdp_prog);
1623         if (xdp_prog && !*skb_xdp) {
1624                 struct xdp_buff xdp;
1625                 void *orig_data;
1626                 u32 act;
1627
1628                 xdp.data_hard_start = buf;
1629                 xdp.data = buf + pad;
1630                 xdp_set_data_meta_invalid(&xdp);
1631                 xdp.data_end = xdp.data + len;
1632                 xdp.rxq = &tfile->xdp_rxq;
1633                 orig_data = xdp.data;
1634                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1635
1636                 switch (act) {
1637                 case XDP_REDIRECT:
1638                         get_page(alloc_frag->page);
1639                         alloc_frag->offset += buflen;
1640                         err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
1641                         xdp_do_flush_map();
1642                         if (err)
1643                                 goto err_redirect;
1644                         rcu_read_unlock();
1645                         local_bh_enable();
1646                         return NULL;
1647                 case XDP_TX:
1648                         get_page(alloc_frag->page);
1649                         alloc_frag->offset += buflen;
1650                         if (tun_xdp_tx(tun->dev, &xdp) < 0)
1651                                 goto err_redirect;
1652                         rcu_read_unlock();
1653                         local_bh_enable();
1654                         return NULL;
1655                 case XDP_PASS:
1656                         delta = orig_data - xdp.data;
1657                         len = xdp.data_end - xdp.data;
1658                         break;
1659                 default:
1660                         bpf_warn_invalid_xdp_action(act);
1661                         /* fall through */
1662                 case XDP_ABORTED:
1663                         trace_xdp_exception(tun->dev, xdp_prog, act);
1664                         /* fall through */
1665                 case XDP_DROP:
1666                         goto err_xdp;
1667                 }
1668         }
1669
1670         skb = build_skb(buf, buflen);
1671         if (!skb) {
1672                 rcu_read_unlock();
1673                 local_bh_enable();
1674                 return ERR_PTR(-ENOMEM);
1675         }
1676
1677         skb_reserve(skb, pad - delta);
1678         skb_put(skb, len);
1679         get_page(alloc_frag->page);
1680         alloc_frag->offset += buflen;
1681
1682         rcu_read_unlock();
1683         local_bh_enable();
1684
1685         return skb;
1686
1687 err_redirect:
1688         put_page(alloc_frag->page);
1689 err_xdp:
1690         rcu_read_unlock();
1691         local_bh_enable();
1692         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1693         return NULL;
1694 }
1695
1696 /* Get packet from user space buffer */
1697 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1698                             void *msg_control, struct iov_iter *from,
1699                             int noblock, bool more)
1700 {
1701         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1702         struct sk_buff *skb;
1703         size_t total_len = iov_iter_count(from);
1704         size_t len = total_len, align = tun->align, linear;
1705         struct virtio_net_hdr gso = { 0 };
1706         struct tun_pcpu_stats *stats;
1707         int good_linear;
1708         int copylen;
1709         bool zerocopy = false;
1710         int err;
1711         u32 rxhash = 0;
1712         int skb_xdp = 1;
1713         bool frags = tun_napi_frags_enabled(tfile);
1714
1715         if (!(tun->dev->flags & IFF_UP))
1716                 return -EIO;
1717
1718         if (!(tun->flags & IFF_NO_PI)) {
1719                 if (len < sizeof(pi))
1720                         return -EINVAL;
1721                 len -= sizeof(pi);
1722
1723                 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1724                         return -EFAULT;
1725         }
1726
1727         if (tun->flags & IFF_VNET_HDR) {
1728                 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1729
1730                 if (len < vnet_hdr_sz)
1731                         return -EINVAL;
1732                 len -= vnet_hdr_sz;
1733
1734                 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1735                         return -EFAULT;
1736
1737                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1738                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1739                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1740
1741                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1742                         return -EINVAL;
1743                 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1744         }
1745
1746         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1747                 align += NET_IP_ALIGN;
1748                 if (unlikely(len < ETH_HLEN ||
1749                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1750                         return -EINVAL;
1751         }
1752
1753         good_linear = SKB_MAX_HEAD(align);
1754
1755         if (msg_control) {
1756                 struct iov_iter i = *from;
1757
1758                 /* There are 256 bytes to be copied in skb, so there is
1759                  * enough room for skb expand head in case it is used.
1760                  * The rest of the buffer is mapped from userspace.
1761                  */
1762                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1763                 if (copylen > good_linear)
1764                         copylen = good_linear;
1765                 linear = copylen;
1766                 iov_iter_advance(&i, copylen);
1767                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1768                         zerocopy = true;
1769         }
1770
1771         if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1772                 /* For the packet that is not easy to be processed
1773                  * (e.g gso or jumbo packet), we will do it at after
1774                  * skb was created with generic XDP routine.
1775                  */
1776                 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1777                 if (IS_ERR(skb)) {
1778                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1779                         return PTR_ERR(skb);
1780                 }
1781                 if (!skb)
1782                         return total_len;
1783         } else {
1784                 if (!zerocopy) {
1785                         copylen = len;
1786                         if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1787                                 linear = good_linear;
1788                         else
1789                                 linear = tun16_to_cpu(tun, gso.hdr_len);
1790                 }
1791
1792                 if (frags) {
1793                         mutex_lock(&tfile->napi_mutex);
1794                         skb = tun_napi_alloc_frags(tfile, copylen, from);
1795                         /* tun_napi_alloc_frags() enforces a layout for the skb.
1796                          * If zerocopy is enabled, then this layout will be
1797                          * overwritten by zerocopy_sg_from_iter().
1798                          */
1799                         zerocopy = false;
1800                 } else {
1801                         skb = tun_alloc_skb(tfile, align, copylen, linear,
1802                                             noblock);
1803                 }
1804
1805                 if (IS_ERR(skb)) {
1806                         if (PTR_ERR(skb) != -EAGAIN)
1807                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1808                         if (frags)
1809                                 mutex_unlock(&tfile->napi_mutex);
1810                         return PTR_ERR(skb);
1811                 }
1812
1813                 if (zerocopy)
1814                         err = zerocopy_sg_from_iter(skb, from);
1815                 else
1816                         err = skb_copy_datagram_from_iter(skb, 0, from, len);
1817
1818                 if (err) {
1819                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1820                         kfree_skb(skb);
1821                         if (frags) {
1822                                 tfile->napi.skb = NULL;
1823                                 mutex_unlock(&tfile->napi_mutex);
1824                         }
1825
1826                         return -EFAULT;
1827                 }
1828         }
1829
1830         if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1831                 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1832                 kfree_skb(skb);
1833                 if (frags) {
1834                         tfile->napi.skb = NULL;
1835                         mutex_unlock(&tfile->napi_mutex);
1836                 }
1837
1838                 return -EINVAL;
1839         }
1840
1841         switch (tun->flags & TUN_TYPE_MASK) {
1842         case IFF_TUN:
1843                 if (tun->flags & IFF_NO_PI) {
1844                         u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1845
1846                         switch (ip_version) {
1847                         case 4:
1848                                 pi.proto = htons(ETH_P_IP);
1849                                 break;
1850                         case 6:
1851                                 pi.proto = htons(ETH_P_IPV6);
1852                                 break;
1853                         default:
1854                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1855                                 kfree_skb(skb);
1856                                 return -EINVAL;
1857                         }
1858                 }
1859
1860                 skb_reset_mac_header(skb);
1861                 skb->protocol = pi.proto;
1862                 skb->dev = tun->dev;
1863                 break;
1864         case IFF_TAP:
1865                 if (!frags)
1866                         skb->protocol = eth_type_trans(skb, tun->dev);
1867                 break;
1868         }
1869
1870         /* copy skb_ubuf_info for callback when skb has no error */
1871         if (zerocopy) {
1872                 skb_shinfo(skb)->destructor_arg = msg_control;
1873                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1874                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1875         } else if (msg_control) {
1876                 struct ubuf_info *uarg = msg_control;
1877                 uarg->callback(uarg, false);
1878         }
1879
1880         skb_reset_network_header(skb);
1881         skb_probe_transport_header(skb, 0);
1882
1883         if (skb_xdp) {
1884                 struct bpf_prog *xdp_prog;
1885                 int ret;
1886
1887                 local_bh_disable();
1888                 rcu_read_lock();
1889                 xdp_prog = rcu_dereference(tun->xdp_prog);
1890                 if (xdp_prog) {
1891                         ret = do_xdp_generic(xdp_prog, skb);
1892                         if (ret != XDP_PASS) {
1893                                 rcu_read_unlock();
1894                                 local_bh_enable();
1895                                 return total_len;
1896                         }
1897                 }
1898                 rcu_read_unlock();
1899                 local_bh_enable();
1900         }
1901
1902         /* Compute the costly rx hash only if needed for flow updates.
1903          * We may get a very small possibility of OOO during switching, not
1904          * worth to optimize.
1905          */
1906         if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1907             !tfile->detached)
1908                 rxhash = __skb_get_hash_symmetric(skb);
1909
1910         if (frags) {
1911                 /* Exercise flow dissector code path. */
1912                 u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb));
1913
1914                 if (unlikely(headlen > skb_headlen(skb))) {
1915                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1916                         napi_free_frags(&tfile->napi);
1917                         mutex_unlock(&tfile->napi_mutex);
1918                         WARN_ON(1);
1919                         return -ENOMEM;
1920                 }
1921
1922                 local_bh_disable();
1923                 napi_gro_frags(&tfile->napi);
1924                 local_bh_enable();
1925                 mutex_unlock(&tfile->napi_mutex);
1926         } else if (tfile->napi_enabled) {
1927                 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1928                 int queue_len;
1929
1930                 spin_lock_bh(&queue->lock);
1931                 __skb_queue_tail(queue, skb);
1932                 queue_len = skb_queue_len(queue);
1933                 spin_unlock(&queue->lock);
1934
1935                 if (!more || queue_len > NAPI_POLL_WEIGHT)
1936                         napi_schedule(&tfile->napi);
1937
1938                 local_bh_enable();
1939         } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1940                 tun_rx_batched(tun, tfile, skb, more);
1941         } else {
1942                 netif_rx_ni(skb);
1943         }
1944
1945         stats = get_cpu_ptr(tun->pcpu_stats);
1946         u64_stats_update_begin(&stats->syncp);
1947         stats->rx_packets++;
1948         stats->rx_bytes += len;
1949         u64_stats_update_end(&stats->syncp);
1950         put_cpu_ptr(stats);
1951
1952         if (rxhash)
1953                 tun_flow_update(tun, rxhash, tfile);
1954
1955         return total_len;
1956 }
1957
1958 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1959 {
1960         struct file *file = iocb->ki_filp;
1961         struct tun_file *tfile = file->private_data;
1962         struct tun_struct *tun = tun_get(tfile);
1963         ssize_t result;
1964
1965         if (!tun)
1966                 return -EBADFD;
1967
1968         result = tun_get_user(tun, tfile, NULL, from,
1969                               file->f_flags & O_NONBLOCK, false);
1970
1971         tun_put(tun);
1972         return result;
1973 }
1974
1975 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
1976                                 struct tun_file *tfile,
1977                                 struct xdp_frame *xdp_frame,
1978                                 struct iov_iter *iter)
1979 {
1980         int vnet_hdr_sz = 0;
1981         size_t size = xdp_frame->len;
1982         struct tun_pcpu_stats *stats;
1983         size_t ret;
1984
1985         if (tun->flags & IFF_VNET_HDR) {
1986                 struct virtio_net_hdr gso = { 0 };
1987
1988                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1989                 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
1990                         return -EINVAL;
1991                 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
1992                              sizeof(gso)))
1993                         return -EFAULT;
1994                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1995         }
1996
1997         ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
1998
1999         stats = get_cpu_ptr(tun->pcpu_stats);
2000         u64_stats_update_begin(&stats->syncp);
2001         stats->tx_packets++;
2002         stats->tx_bytes += ret;
2003         u64_stats_update_end(&stats->syncp);
2004         put_cpu_ptr(tun->pcpu_stats);
2005
2006         return ret;
2007 }
2008
2009 /* Put packet to the user space buffer */
2010 static ssize_t tun_put_user(struct tun_struct *tun,
2011                             struct tun_file *tfile,
2012                             struct sk_buff *skb,
2013                             struct iov_iter *iter)
2014 {
2015         struct tun_pi pi = { 0, skb->protocol };
2016         struct tun_pcpu_stats *stats;
2017         ssize_t total;
2018         int vlan_offset = 0;
2019         int vlan_hlen = 0;
2020         int vnet_hdr_sz = 0;
2021
2022         if (skb_vlan_tag_present(skb))
2023                 vlan_hlen = VLAN_HLEN;
2024
2025         if (tun->flags & IFF_VNET_HDR)
2026                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2027
2028         total = skb->len + vlan_hlen + vnet_hdr_sz;
2029
2030         if (!(tun->flags & IFF_NO_PI)) {
2031                 if (iov_iter_count(iter) < sizeof(pi))
2032                         return -EINVAL;
2033
2034                 total += sizeof(pi);
2035                 if (iov_iter_count(iter) < total) {
2036                         /* Packet will be striped */
2037                         pi.flags |= TUN_PKT_STRIP;
2038                 }
2039
2040                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2041                         return -EFAULT;
2042         }
2043
2044         if (vnet_hdr_sz) {
2045                 struct virtio_net_hdr gso;
2046
2047                 if (iov_iter_count(iter) < vnet_hdr_sz)
2048                         return -EINVAL;
2049
2050                 if (virtio_net_hdr_from_skb(skb, &gso,
2051                                             tun_is_little_endian(tun), true,
2052                                             vlan_hlen)) {
2053                         struct skb_shared_info *sinfo = skb_shinfo(skb);
2054                         pr_err("unexpected GSO type: "
2055                                "0x%x, gso_size %d, hdr_len %d\n",
2056                                sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2057                                tun16_to_cpu(tun, gso.hdr_len));
2058                         print_hex_dump(KERN_ERR, "tun: ",
2059                                        DUMP_PREFIX_NONE,
2060                                        16, 1, skb->head,
2061                                        min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2062                         WARN_ON_ONCE(1);
2063                         return -EINVAL;
2064                 }
2065
2066                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2067                         return -EFAULT;
2068
2069                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2070         }
2071
2072         if (vlan_hlen) {
2073                 int ret;
2074                 struct veth veth;
2075
2076                 veth.h_vlan_proto = skb->vlan_proto;
2077                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2078
2079                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2080
2081                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2082                 if (ret || !iov_iter_count(iter))
2083                         goto done;
2084
2085                 ret = copy_to_iter(&veth, sizeof(veth), iter);
2086                 if (ret != sizeof(veth) || !iov_iter_count(iter))
2087                         goto done;
2088         }
2089
2090         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2091
2092 done:
2093         /* caller is in process context, */
2094         stats = get_cpu_ptr(tun->pcpu_stats);
2095         u64_stats_update_begin(&stats->syncp);
2096         stats->tx_packets++;
2097         stats->tx_bytes += skb->len + vlan_hlen;
2098         u64_stats_update_end(&stats->syncp);
2099         put_cpu_ptr(tun->pcpu_stats);
2100
2101         return total;
2102 }
2103
2104 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2105 {
2106         DECLARE_WAITQUEUE(wait, current);
2107         void *ptr = NULL;
2108         int error = 0;
2109
2110         ptr = ptr_ring_consume(&tfile->tx_ring);
2111         if (ptr)
2112                 goto out;
2113         if (noblock) {
2114                 error = -EAGAIN;
2115                 goto out;
2116         }
2117
2118         add_wait_queue(&tfile->wq.wait, &wait);
2119         current->state = TASK_INTERRUPTIBLE;
2120
2121         while (1) {
2122                 ptr = ptr_ring_consume(&tfile->tx_ring);
2123                 if (ptr)
2124                         break;
2125                 if (signal_pending(current)) {
2126                         error = -ERESTARTSYS;
2127                         break;
2128                 }
2129                 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2130                         error = -EFAULT;
2131                         break;
2132                 }
2133
2134                 schedule();
2135         }
2136
2137         current->state = TASK_RUNNING;
2138         remove_wait_queue(&tfile->wq.wait, &wait);
2139
2140 out:
2141         *err = error;
2142         return ptr;
2143 }
2144
2145 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2146                            struct iov_iter *to,
2147                            int noblock, void *ptr)
2148 {
2149         ssize_t ret;
2150         int err;
2151
2152         tun_debug(KERN_INFO, tun, "tun_do_read\n");
2153
2154         if (!iov_iter_count(to)) {
2155                 tun_ptr_free(ptr);
2156                 return 0;
2157         }
2158
2159         if (!ptr) {
2160                 /* Read frames from ring */
2161                 ptr = tun_ring_recv(tfile, noblock, &err);
2162                 if (!ptr)
2163                         return err;
2164         }
2165
2166         if (tun_is_xdp_frame(ptr)) {
2167                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2168
2169                 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2170                 xdp_return_frame(xdpf);
2171         } else {
2172                 struct sk_buff *skb = ptr;
2173
2174                 ret = tun_put_user(tun, tfile, skb, to);
2175                 if (unlikely(ret < 0))
2176                         kfree_skb(skb);
2177                 else
2178                         consume_skb(skb);
2179         }
2180
2181         return ret;
2182 }
2183
2184 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2185 {
2186         struct file *file = iocb->ki_filp;
2187         struct tun_file *tfile = file->private_data;
2188         struct tun_struct *tun = tun_get(tfile);
2189         ssize_t len = iov_iter_count(to), ret;
2190
2191         if (!tun)
2192                 return -EBADFD;
2193         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2194         ret = min_t(ssize_t, ret, len);
2195         if (ret > 0)
2196                 iocb->ki_pos = ret;
2197         tun_put(tun);
2198         return ret;
2199 }
2200
2201 static void tun_prog_free(struct rcu_head *rcu)
2202 {
2203         struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2204
2205         bpf_prog_destroy(prog->prog);
2206         kfree(prog);
2207 }
2208
2209 static int __tun_set_ebpf(struct tun_struct *tun,
2210                           struct tun_prog __rcu **prog_p,
2211                           struct bpf_prog *prog)
2212 {
2213         struct tun_prog *old, *new = NULL;
2214
2215         if (prog) {
2216                 new = kmalloc(sizeof(*new), GFP_KERNEL);
2217                 if (!new)
2218                         return -ENOMEM;
2219                 new->prog = prog;
2220         }
2221
2222         spin_lock_bh(&tun->lock);
2223         old = rcu_dereference_protected(*prog_p,
2224                                         lockdep_is_held(&tun->lock));
2225         rcu_assign_pointer(*prog_p, new);
2226         spin_unlock_bh(&tun->lock);
2227
2228         if (old)
2229                 call_rcu(&old->rcu, tun_prog_free);
2230
2231         return 0;
2232 }
2233
2234 static void tun_free_netdev(struct net_device *dev)
2235 {
2236         struct tun_struct *tun = netdev_priv(dev);
2237
2238         BUG_ON(!(list_empty(&tun->disabled)));
2239         free_percpu(tun->pcpu_stats);
2240         tun_flow_uninit(tun);
2241         security_tun_dev_free_security(tun->security);
2242         __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2243         __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2244 }
2245
2246 static void tun_setup(struct net_device *dev)
2247 {
2248         struct tun_struct *tun = netdev_priv(dev);
2249
2250         tun->owner = INVALID_UID;
2251         tun->group = INVALID_GID;
2252         tun_default_link_ksettings(dev, &tun->link_ksettings);
2253
2254         dev->ethtool_ops = &tun_ethtool_ops;
2255         dev->needs_free_netdev = true;
2256         dev->priv_destructor = tun_free_netdev;
2257         /* We prefer our own queue length */
2258         dev->tx_queue_len = TUN_READQ_SIZE;
2259 }
2260
2261 /* Trivial set of netlink ops to allow deleting tun or tap
2262  * device with netlink.
2263  */
2264 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2265                         struct netlink_ext_ack *extack)
2266 {
2267         return -EINVAL;
2268 }
2269
2270 static size_t tun_get_size(const struct net_device *dev)
2271 {
2272         BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2273         BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2274
2275         return nla_total_size(sizeof(uid_t)) + /* OWNER */
2276                nla_total_size(sizeof(gid_t)) + /* GROUP */
2277                nla_total_size(sizeof(u8)) + /* TYPE */
2278                nla_total_size(sizeof(u8)) + /* PI */
2279                nla_total_size(sizeof(u8)) + /* VNET_HDR */
2280                nla_total_size(sizeof(u8)) + /* PERSIST */
2281                nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2282                nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2283                nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2284                0;
2285 }
2286
2287 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2288 {
2289         struct tun_struct *tun = netdev_priv(dev);
2290
2291         if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2292                 goto nla_put_failure;
2293         if (uid_valid(tun->owner) &&
2294             nla_put_u32(skb, IFLA_TUN_OWNER,
2295                         from_kuid_munged(current_user_ns(), tun->owner)))
2296                 goto nla_put_failure;
2297         if (gid_valid(tun->group) &&
2298             nla_put_u32(skb, IFLA_TUN_GROUP,
2299                         from_kgid_munged(current_user_ns(), tun->group)))
2300                 goto nla_put_failure;
2301         if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2302                 goto nla_put_failure;
2303         if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2304                 goto nla_put_failure;
2305         if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2306                 goto nla_put_failure;
2307         if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2308                        !!(tun->flags & IFF_MULTI_QUEUE)))
2309                 goto nla_put_failure;
2310         if (tun->flags & IFF_MULTI_QUEUE) {
2311                 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2312                         goto nla_put_failure;
2313                 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2314                                 tun->numdisabled))
2315                         goto nla_put_failure;
2316         }
2317
2318         return 0;
2319
2320 nla_put_failure:
2321         return -EMSGSIZE;
2322 }
2323
2324 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2325         .kind           = DRV_NAME,
2326         .priv_size      = sizeof(struct tun_struct),
2327         .setup          = tun_setup,
2328         .validate       = tun_validate,
2329         .get_size       = tun_get_size,
2330         .fill_info      = tun_fill_info,
2331 };
2332
2333 static void tun_sock_write_space(struct sock *sk)
2334 {
2335         struct tun_file *tfile;
2336         wait_queue_head_t *wqueue;
2337
2338         if (!sock_writeable(sk))
2339                 return;
2340
2341         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2342                 return;
2343
2344         wqueue = sk_sleep(sk);
2345         if (wqueue && waitqueue_active(wqueue))
2346                 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2347                                                 EPOLLWRNORM | EPOLLWRBAND);
2348
2349         tfile = container_of(sk, struct tun_file, sk);
2350         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2351 }
2352
2353 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2354 {
2355         int ret;
2356         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2357         struct tun_struct *tun = tun_get(tfile);
2358
2359         if (!tun)
2360                 return -EBADFD;
2361
2362         ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
2363                            m->msg_flags & MSG_DONTWAIT,
2364                            m->msg_flags & MSG_MORE);
2365         tun_put(tun);
2366         return ret;
2367 }
2368
2369 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2370                        int flags)
2371 {
2372         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2373         struct tun_struct *tun = tun_get(tfile);
2374         void *ptr = m->msg_control;
2375         int ret;
2376
2377         if (!tun) {
2378                 ret = -EBADFD;
2379                 goto out_free;
2380         }
2381
2382         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2383                 ret = -EINVAL;
2384                 goto out_put_tun;
2385         }
2386         if (flags & MSG_ERRQUEUE) {
2387                 ret = sock_recv_errqueue(sock->sk, m, total_len,
2388                                          SOL_PACKET, TUN_TX_TIMESTAMP);
2389                 goto out;
2390         }
2391         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2392         if (ret > (ssize_t)total_len) {
2393                 m->msg_flags |= MSG_TRUNC;
2394                 ret = flags & MSG_TRUNC ? ret : total_len;
2395         }
2396 out:
2397         tun_put(tun);
2398         return ret;
2399
2400 out_put_tun:
2401         tun_put(tun);
2402 out_free:
2403         tun_ptr_free(ptr);
2404         return ret;
2405 }
2406
2407 static int tun_ptr_peek_len(void *ptr)
2408 {
2409         if (likely(ptr)) {
2410                 if (tun_is_xdp_frame(ptr)) {
2411                         struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2412
2413                         return xdpf->len;
2414                 }
2415                 return __skb_array_len_with_tag(ptr);
2416         } else {
2417                 return 0;
2418         }
2419 }
2420
2421 static int tun_peek_len(struct socket *sock)
2422 {
2423         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2424         struct tun_struct *tun;
2425         int ret = 0;
2426
2427         tun = tun_get(tfile);
2428         if (!tun)
2429                 return 0;
2430
2431         ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2432         tun_put(tun);
2433
2434         return ret;
2435 }
2436
2437 /* Ops structure to mimic raw sockets with tun */
2438 static const struct proto_ops tun_socket_ops = {
2439         .peek_len = tun_peek_len,
2440         .sendmsg = tun_sendmsg,
2441         .recvmsg = tun_recvmsg,
2442 };
2443
2444 static struct proto tun_proto = {
2445         .name           = "tun",
2446         .owner          = THIS_MODULE,
2447         .obj_size       = sizeof(struct tun_file),
2448 };
2449
2450 static int tun_flags(struct tun_struct *tun)
2451 {
2452         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2453 }
2454
2455 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2456                               char *buf)
2457 {
2458         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2459         return sprintf(buf, "0x%x\n", tun_flags(tun));
2460 }
2461
2462 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2463                               char *buf)
2464 {
2465         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2466         return uid_valid(tun->owner)?
2467                 sprintf(buf, "%u\n",
2468                         from_kuid_munged(current_user_ns(), tun->owner)):
2469                 sprintf(buf, "-1\n");
2470 }
2471
2472 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2473                               char *buf)
2474 {
2475         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2476         return gid_valid(tun->group) ?
2477                 sprintf(buf, "%u\n",
2478                         from_kgid_munged(current_user_ns(), tun->group)):
2479                 sprintf(buf, "-1\n");
2480 }
2481
2482 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2483 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2484 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2485
2486 static struct attribute *tun_dev_attrs[] = {
2487         &dev_attr_tun_flags.attr,
2488         &dev_attr_owner.attr,
2489         &dev_attr_group.attr,
2490         NULL
2491 };
2492
2493 static const struct attribute_group tun_attr_group = {
2494         .attrs = tun_dev_attrs
2495 };
2496
2497 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2498 {
2499         struct tun_struct *tun;
2500         struct tun_file *tfile = file->private_data;
2501         struct net_device *dev;
2502         int err;
2503
2504         if (tfile->detached)
2505                 return -EINVAL;
2506
2507         if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2508                 if (!capable(CAP_NET_ADMIN))
2509                         return -EPERM;
2510
2511                 if (!(ifr->ifr_flags & IFF_NAPI) ||
2512                     (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2513                         return -EINVAL;
2514         }
2515
2516         dev = __dev_get_by_name(net, ifr->ifr_name);
2517         if (dev) {
2518                 if (ifr->ifr_flags & IFF_TUN_EXCL)
2519                         return -EBUSY;
2520                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2521                         tun = netdev_priv(dev);
2522                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2523                         tun = netdev_priv(dev);
2524                 else
2525                         return -EINVAL;
2526
2527                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2528                     !!(tun->flags & IFF_MULTI_QUEUE))
2529                         return -EINVAL;
2530
2531                 if (tun_not_capable(tun))
2532                         return -EPERM;
2533                 err = security_tun_dev_open(tun->security);
2534                 if (err < 0)
2535                         return err;
2536
2537                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2538                                  ifr->ifr_flags & IFF_NAPI,
2539                                  ifr->ifr_flags & IFF_NAPI_FRAGS);
2540                 if (err < 0)
2541                         return err;
2542
2543                 if (tun->flags & IFF_MULTI_QUEUE &&
2544                     (tun->numqueues + tun->numdisabled > 1)) {
2545                         /* One or more queue has already been attached, no need
2546                          * to initialize the device again.
2547                          */
2548                         netdev_state_change(dev);
2549                         return 0;
2550                 }
2551
2552                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2553                               (ifr->ifr_flags & TUN_FEATURES);
2554
2555                 netdev_state_change(dev);
2556         } else {
2557                 char *name;
2558                 unsigned long flags = 0;
2559                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2560                              MAX_TAP_QUEUES : 1;
2561
2562                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2563                         return -EPERM;
2564                 err = security_tun_dev_create();
2565                 if (err < 0)
2566                         return err;
2567
2568                 /* Set dev type */
2569                 if (ifr->ifr_flags & IFF_TUN) {
2570                         /* TUN device */
2571                         flags |= IFF_TUN;
2572                         name = "tun%d";
2573                 } else if (ifr->ifr_flags & IFF_TAP) {
2574                         /* TAP device */
2575                         flags |= IFF_TAP;
2576                         name = "tap%d";
2577                 } else
2578                         return -EINVAL;
2579
2580                 if (*ifr->ifr_name)
2581                         name = ifr->ifr_name;
2582
2583                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2584                                        NET_NAME_UNKNOWN, tun_setup, queues,
2585                                        queues);
2586
2587                 if (!dev)
2588                         return -ENOMEM;
2589                 err = dev_get_valid_name(net, dev, name);
2590                 if (err < 0)
2591                         goto err_free_dev;
2592
2593                 dev_net_set(dev, net);
2594                 dev->rtnl_link_ops = &tun_link_ops;
2595                 dev->ifindex = tfile->ifindex;
2596                 dev->sysfs_groups[0] = &tun_attr_group;
2597
2598                 tun = netdev_priv(dev);
2599                 tun->dev = dev;
2600                 tun->flags = flags;
2601                 tun->txflt.count = 0;
2602                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2603
2604                 tun->align = NET_SKB_PAD;
2605                 tun->filter_attached = false;
2606                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2607                 tun->rx_batched = 0;
2608                 RCU_INIT_POINTER(tun->steering_prog, NULL);
2609
2610                 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2611                 if (!tun->pcpu_stats) {
2612                         err = -ENOMEM;
2613                         goto err_free_dev;
2614                 }
2615
2616                 spin_lock_init(&tun->lock);
2617
2618                 err = security_tun_dev_alloc_security(&tun->security);
2619                 if (err < 0)
2620                         goto err_free_stat;
2621
2622                 tun_net_init(dev);
2623                 tun_flow_init(tun);
2624
2625                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2626                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2627                                    NETIF_F_HW_VLAN_STAG_TX;
2628                 dev->features = dev->hw_features | NETIF_F_LLTX;
2629                 dev->vlan_features = dev->features &
2630                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
2631                                        NETIF_F_HW_VLAN_STAG_TX);
2632
2633                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2634                               (ifr->ifr_flags & TUN_FEATURES);
2635
2636                 INIT_LIST_HEAD(&tun->disabled);
2637                 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI,
2638                                  ifr->ifr_flags & IFF_NAPI_FRAGS);
2639                 if (err < 0)
2640                         goto err_free_flow;
2641
2642                 err = register_netdevice(tun->dev);
2643                 if (err < 0)
2644                         goto err_detach;
2645         }
2646
2647         netif_carrier_on(tun->dev);
2648
2649         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2650
2651         /* Make sure persistent devices do not get stuck in
2652          * xoff state.
2653          */
2654         if (netif_running(tun->dev))
2655                 netif_tx_wake_all_queues(tun->dev);
2656
2657         strcpy(ifr->ifr_name, tun->dev->name);
2658         return 0;
2659
2660 err_detach:
2661         tun_detach_all(dev);
2662         /* register_netdevice() already called tun_free_netdev() */
2663         goto err_free_dev;
2664
2665 err_free_flow:
2666         tun_flow_uninit(tun);
2667         security_tun_dev_free_security(tun->security);
2668 err_free_stat:
2669         free_percpu(tun->pcpu_stats);
2670 err_free_dev:
2671         free_netdev(dev);
2672         return err;
2673 }
2674
2675 static void tun_get_iff(struct net *net, struct tun_struct *tun,
2676                        struct ifreq *ifr)
2677 {
2678         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2679
2680         strcpy(ifr->ifr_name, tun->dev->name);
2681
2682         ifr->ifr_flags = tun_flags(tun);
2683
2684 }
2685
2686 /* This is like a cut-down ethtool ops, except done via tun fd so no
2687  * privs required. */
2688 static int set_offload(struct tun_struct *tun, unsigned long arg)
2689 {
2690         netdev_features_t features = 0;
2691
2692         if (arg & TUN_F_CSUM) {
2693                 features |= NETIF_F_HW_CSUM;
2694                 arg &= ~TUN_F_CSUM;
2695
2696                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2697                         if (arg & TUN_F_TSO_ECN) {
2698                                 features |= NETIF_F_TSO_ECN;
2699                                 arg &= ~TUN_F_TSO_ECN;
2700                         }
2701                         if (arg & TUN_F_TSO4)
2702                                 features |= NETIF_F_TSO;
2703                         if (arg & TUN_F_TSO6)
2704                                 features |= NETIF_F_TSO6;
2705                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2706                 }
2707
2708                 arg &= ~TUN_F_UFO;
2709         }
2710
2711         /* This gives the user a way to test for new features in future by
2712          * trying to set them. */
2713         if (arg)
2714                 return -EINVAL;
2715
2716         tun->set_features = features;
2717         tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2718         tun->dev->wanted_features |= features;
2719         netdev_update_features(tun->dev);
2720
2721         return 0;
2722 }
2723
2724 static void tun_detach_filter(struct tun_struct *tun, int n)
2725 {
2726         int i;
2727         struct tun_file *tfile;
2728
2729         for (i = 0; i < n; i++) {
2730                 tfile = rtnl_dereference(tun->tfiles[i]);
2731                 lock_sock(tfile->socket.sk);
2732                 sk_detach_filter(tfile->socket.sk);
2733                 release_sock(tfile->socket.sk);
2734         }
2735
2736         tun->filter_attached = false;
2737 }
2738
2739 static int tun_attach_filter(struct tun_struct *tun)
2740 {
2741         int i, ret = 0;
2742         struct tun_file *tfile;
2743
2744         for (i = 0; i < tun->numqueues; i++) {
2745                 tfile = rtnl_dereference(tun->tfiles[i]);
2746                 lock_sock(tfile->socket.sk);
2747                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2748                 release_sock(tfile->socket.sk);
2749                 if (ret) {
2750                         tun_detach_filter(tun, i);
2751                         return ret;
2752                 }
2753         }
2754
2755         tun->filter_attached = true;
2756         return ret;
2757 }
2758
2759 static void tun_set_sndbuf(struct tun_struct *tun)
2760 {
2761         struct tun_file *tfile;
2762         int i;
2763
2764         for (i = 0; i < tun->numqueues; i++) {
2765                 tfile = rtnl_dereference(tun->tfiles[i]);
2766                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2767         }
2768 }
2769
2770 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2771 {
2772         struct tun_file *tfile = file->private_data;
2773         struct tun_struct *tun;
2774         int ret = 0;
2775
2776         rtnl_lock();
2777
2778         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2779                 tun = tfile->detached;
2780                 if (!tun) {
2781                         ret = -EINVAL;
2782                         goto unlock;
2783                 }
2784                 ret = security_tun_dev_attach_queue(tun->security);
2785                 if (ret < 0)
2786                         goto unlock;
2787                 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2788                                  tun->flags & IFF_NAPI_FRAGS);
2789         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2790                 tun = rtnl_dereference(tfile->tun);
2791                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2792                         ret = -EINVAL;
2793                 else
2794                         __tun_detach(tfile, false);
2795         } else
2796                 ret = -EINVAL;
2797
2798         if (ret >= 0)
2799                 netdev_state_change(tun->dev);
2800
2801 unlock:
2802         rtnl_unlock();
2803         return ret;
2804 }
2805
2806 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
2807                         void __user *data)
2808 {
2809         struct bpf_prog *prog;
2810         int fd;
2811
2812         if (copy_from_user(&fd, data, sizeof(fd)))
2813                 return -EFAULT;
2814
2815         if (fd == -1) {
2816                 prog = NULL;
2817         } else {
2818                 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
2819                 if (IS_ERR(prog))
2820                         return PTR_ERR(prog);
2821         }
2822
2823         return __tun_set_ebpf(tun, prog_p, prog);
2824 }
2825
2826 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2827                             unsigned long arg, int ifreq_len)
2828 {
2829         struct tun_file *tfile = file->private_data;
2830         struct net *net = sock_net(&tfile->sk);
2831         struct tun_struct *tun;
2832         void __user* argp = (void __user*)arg;
2833         struct ifreq ifr;
2834         kuid_t owner;
2835         kgid_t group;
2836         int sndbuf;
2837         int vnet_hdr_sz;
2838         unsigned int ifindex;
2839         int le;
2840         int ret;
2841         bool do_notify = false;
2842
2843         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
2844             (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
2845                 if (copy_from_user(&ifr, argp, ifreq_len))
2846                         return -EFAULT;
2847         } else {
2848                 memset(&ifr, 0, sizeof(ifr));
2849         }
2850         if (cmd == TUNGETFEATURES) {
2851                 /* Currently this just means: "what IFF flags are valid?".
2852                  * This is needed because we never checked for invalid flags on
2853                  * TUNSETIFF.
2854                  */
2855                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2856                                 (unsigned int __user*)argp);
2857         } else if (cmd == TUNSETQUEUE) {
2858                 return tun_set_queue(file, &ifr);
2859         } else if (cmd == SIOCGSKNS) {
2860                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2861                         return -EPERM;
2862                 return open_related_ns(&net->ns, get_net_ns);
2863         }
2864
2865         ret = 0;
2866         rtnl_lock();
2867
2868         tun = tun_get(tfile);
2869         if (cmd == TUNSETIFF) {
2870                 ret = -EEXIST;
2871                 if (tun)
2872                         goto unlock;
2873
2874                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2875
2876                 ret = tun_set_iff(net, file, &ifr);
2877
2878                 if (ret)
2879                         goto unlock;
2880
2881                 if (copy_to_user(argp, &ifr, ifreq_len))
2882                         ret = -EFAULT;
2883                 goto unlock;
2884         }
2885         if (cmd == TUNSETIFINDEX) {
2886                 ret = -EPERM;
2887                 if (tun)
2888                         goto unlock;
2889
2890                 ret = -EFAULT;
2891                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2892                         goto unlock;
2893
2894                 ret = 0;
2895                 tfile->ifindex = ifindex;
2896                 goto unlock;
2897         }
2898
2899         ret = -EBADFD;
2900         if (!tun)
2901                 goto unlock;
2902
2903         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2904
2905         ret = 0;
2906         switch (cmd) {
2907         case TUNGETIFF:
2908                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2909
2910                 if (tfile->detached)
2911                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
2912                 if (!tfile->socket.sk->sk_filter)
2913                         ifr.ifr_flags |= IFF_NOFILTER;
2914
2915                 if (copy_to_user(argp, &ifr, ifreq_len))
2916                         ret = -EFAULT;
2917                 break;
2918
2919         case TUNSETNOCSUM:
2920                 /* Disable/Enable checksum */
2921
2922                 /* [unimplemented] */
2923                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2924                           arg ? "disabled" : "enabled");
2925                 break;
2926
2927         case TUNSETPERSIST:
2928                 /* Disable/Enable persist mode. Keep an extra reference to the
2929                  * module to prevent the module being unprobed.
2930                  */
2931                 if (arg && !(tun->flags & IFF_PERSIST)) {
2932                         tun->flags |= IFF_PERSIST;
2933                         __module_get(THIS_MODULE);
2934                         do_notify = true;
2935                 }
2936                 if (!arg && (tun->flags & IFF_PERSIST)) {
2937                         tun->flags &= ~IFF_PERSIST;
2938                         module_put(THIS_MODULE);
2939                         do_notify = true;
2940                 }
2941
2942                 tun_debug(KERN_INFO, tun, "persist %s\n",
2943                           arg ? "enabled" : "disabled");
2944                 break;
2945
2946         case TUNSETOWNER:
2947                 /* Set owner of the device */
2948                 owner = make_kuid(current_user_ns(), arg);
2949                 if (!uid_valid(owner)) {
2950                         ret = -EINVAL;
2951                         break;
2952                 }
2953                 tun->owner = owner;
2954                 do_notify = true;
2955                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2956                           from_kuid(&init_user_ns, tun->owner));
2957                 break;
2958
2959         case TUNSETGROUP:
2960                 /* Set group of the device */
2961                 group = make_kgid(current_user_ns(), arg);
2962                 if (!gid_valid(group)) {
2963                         ret = -EINVAL;
2964                         break;
2965                 }
2966                 tun->group = group;
2967                 do_notify = true;
2968                 tun_debug(KERN_INFO, tun, "group set to %u\n",
2969                           from_kgid(&init_user_ns, tun->group));
2970                 break;
2971
2972         case TUNSETLINK:
2973                 /* Only allow setting the type when the interface is down */
2974                 if (tun->dev->flags & IFF_UP) {
2975                         tun_debug(KERN_INFO, tun,
2976                                   "Linktype set failed because interface is up\n");
2977                         ret = -EBUSY;
2978                 } else {
2979                         tun->dev->type = (int) arg;
2980                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2981                                   tun->dev->type);
2982                         ret = 0;
2983                 }
2984                 break;
2985
2986 #ifdef TUN_DEBUG
2987         case TUNSETDEBUG:
2988                 tun->debug = arg;
2989                 break;
2990 #endif
2991         case TUNSETOFFLOAD:
2992                 ret = set_offload(tun, arg);
2993                 break;
2994
2995         case TUNSETTXFILTER:
2996                 /* Can be set only for TAPs */
2997                 ret = -EINVAL;
2998                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2999                         break;
3000                 ret = update_filter(&tun->txflt, (void __user *)arg);
3001                 break;
3002
3003         case SIOCGIFHWADDR:
3004                 /* Get hw address */
3005                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3006                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3007                 if (copy_to_user(argp, &ifr, ifreq_len))
3008                         ret = -EFAULT;
3009                 break;
3010
3011         case SIOCSIFHWADDR:
3012                 /* Set hw address */
3013                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
3014                           ifr.ifr_hwaddr.sa_data);
3015
3016                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
3017                 break;
3018
3019         case TUNGETSNDBUF:
3020                 sndbuf = tfile->socket.sk->sk_sndbuf;
3021                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3022                         ret = -EFAULT;
3023                 break;
3024
3025         case TUNSETSNDBUF:
3026                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3027                         ret = -EFAULT;
3028                         break;
3029                 }
3030                 if (sndbuf <= 0) {
3031                         ret = -EINVAL;
3032                         break;
3033                 }
3034
3035                 tun->sndbuf = sndbuf;
3036                 tun_set_sndbuf(tun);
3037                 break;
3038
3039         case TUNGETVNETHDRSZ:
3040                 vnet_hdr_sz = tun->vnet_hdr_sz;
3041                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3042                         ret = -EFAULT;
3043                 break;
3044
3045         case TUNSETVNETHDRSZ:
3046                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3047                         ret = -EFAULT;
3048                         break;
3049                 }
3050                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3051                         ret = -EINVAL;
3052                         break;
3053                 }
3054
3055                 tun->vnet_hdr_sz = vnet_hdr_sz;
3056                 break;
3057
3058         case TUNGETVNETLE:
3059                 le = !!(tun->flags & TUN_VNET_LE);
3060                 if (put_user(le, (int __user *)argp))
3061                         ret = -EFAULT;
3062                 break;
3063
3064         case TUNSETVNETLE:
3065                 if (get_user(le, (int __user *)argp)) {
3066                         ret = -EFAULT;
3067                         break;
3068                 }
3069                 if (le)
3070                         tun->flags |= TUN_VNET_LE;
3071                 else
3072                         tun->flags &= ~TUN_VNET_LE;
3073                 break;
3074
3075         case TUNGETVNETBE:
3076                 ret = tun_get_vnet_be(tun, argp);
3077                 break;
3078
3079         case TUNSETVNETBE:
3080                 ret = tun_set_vnet_be(tun, argp);
3081                 break;
3082
3083         case TUNATTACHFILTER:
3084                 /* Can be set only for TAPs */
3085                 ret = -EINVAL;
3086                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3087                         break;
3088                 ret = -EFAULT;
3089                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3090                         break;
3091
3092                 ret = tun_attach_filter(tun);
3093                 break;
3094
3095         case TUNDETACHFILTER:
3096                 /* Can be set only for TAPs */
3097                 ret = -EINVAL;
3098                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3099                         break;
3100                 ret = 0;
3101                 tun_detach_filter(tun, tun->numqueues);
3102                 break;
3103
3104         case TUNGETFILTER:
3105                 ret = -EINVAL;
3106                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3107                         break;
3108                 ret = -EFAULT;
3109                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3110                         break;
3111                 ret = 0;
3112                 break;
3113
3114         case TUNSETSTEERINGEBPF:
3115                 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3116                 break;
3117
3118         case TUNSETFILTEREBPF:
3119                 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3120                 break;
3121
3122         default:
3123                 ret = -EINVAL;
3124                 break;
3125         }
3126
3127         if (do_notify)
3128                 netdev_state_change(tun->dev);
3129
3130 unlock:
3131         rtnl_unlock();
3132         if (tun)
3133                 tun_put(tun);
3134         return ret;
3135 }
3136
3137 static long tun_chr_ioctl(struct file *file,
3138                           unsigned int cmd, unsigned long arg)
3139 {
3140         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3141 }
3142
3143 #ifdef CONFIG_COMPAT
3144 static long tun_chr_compat_ioctl(struct file *file,
3145                          unsigned int cmd, unsigned long arg)
3146 {
3147         switch (cmd) {
3148         case TUNSETIFF:
3149         case TUNGETIFF:
3150         case TUNSETTXFILTER:
3151         case TUNGETSNDBUF:
3152         case TUNSETSNDBUF:
3153         case SIOCGIFHWADDR:
3154         case SIOCSIFHWADDR:
3155                 arg = (unsigned long)compat_ptr(arg);
3156                 break;
3157         default:
3158                 arg = (compat_ulong_t)arg;
3159                 break;
3160         }
3161
3162         /*
3163          * compat_ifreq is shorter than ifreq, so we must not access beyond
3164          * the end of that structure. All fields that are used in this
3165          * driver are compatible though, we don't need to convert the
3166          * contents.
3167          */
3168         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3169 }
3170 #endif /* CONFIG_COMPAT */
3171
3172 static int tun_chr_fasync(int fd, struct file *file, int on)
3173 {
3174         struct tun_file *tfile = file->private_data;
3175         int ret;
3176
3177         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3178                 goto out;
3179
3180         if (on) {
3181                 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3182                 tfile->flags |= TUN_FASYNC;
3183         } else
3184                 tfile->flags &= ~TUN_FASYNC;
3185         ret = 0;
3186 out:
3187         return ret;
3188 }
3189
3190 static int tun_chr_open(struct inode *inode, struct file * file)
3191 {
3192         struct net *net = current->nsproxy->net_ns;
3193         struct tun_file *tfile;
3194
3195         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
3196
3197         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3198                                             &tun_proto, 0);
3199         if (!tfile)
3200                 return -ENOMEM;
3201         if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3202                 sk_free(&tfile->sk);
3203                 return -ENOMEM;
3204         }
3205
3206         mutex_init(&tfile->napi_mutex);
3207         RCU_INIT_POINTER(tfile->tun, NULL);
3208         tfile->flags = 0;
3209         tfile->ifindex = 0;
3210
3211         init_waitqueue_head(&tfile->wq.wait);
3212         RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
3213
3214         tfile->socket.file = file;
3215         tfile->socket.ops = &tun_socket_ops;
3216
3217         sock_init_data(&tfile->socket, &tfile->sk);
3218
3219         tfile->sk.sk_write_space = tun_sock_write_space;
3220         tfile->sk.sk_sndbuf = INT_MAX;
3221
3222         file->private_data = tfile;
3223         INIT_LIST_HEAD(&tfile->next);
3224
3225         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3226
3227         return 0;
3228 }
3229
3230 static int tun_chr_close(struct inode *inode, struct file *file)
3231 {
3232         struct tun_file *tfile = file->private_data;
3233
3234         tun_detach(tfile, true);
3235
3236         return 0;
3237 }
3238
3239 #ifdef CONFIG_PROC_FS
3240 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3241 {
3242         struct tun_file *tfile = file->private_data;
3243         struct tun_struct *tun;
3244         struct ifreq ifr;
3245
3246         memset(&ifr, 0, sizeof(ifr));
3247
3248         rtnl_lock();
3249         tun = tun_get(tfile);
3250         if (tun)
3251                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
3252         rtnl_unlock();
3253
3254         if (tun)
3255                 tun_put(tun);
3256
3257         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3258 }
3259 #endif
3260
3261 static const struct file_operations tun_fops = {
3262         .owner  = THIS_MODULE,
3263         .llseek = no_llseek,
3264         .read_iter  = tun_chr_read_iter,
3265         .write_iter = tun_chr_write_iter,
3266         .poll   = tun_chr_poll,
3267         .unlocked_ioctl = tun_chr_ioctl,
3268 #ifdef CONFIG_COMPAT
3269         .compat_ioctl = tun_chr_compat_ioctl,
3270 #endif
3271         .open   = tun_chr_open,
3272         .release = tun_chr_close,
3273         .fasync = tun_chr_fasync,
3274 #ifdef CONFIG_PROC_FS
3275         .show_fdinfo = tun_chr_show_fdinfo,
3276 #endif
3277 };
3278
3279 static struct miscdevice tun_miscdev = {
3280         .minor = TUN_MINOR,
3281         .name = "tun",
3282         .nodename = "net/tun",
3283         .fops = &tun_fops,
3284 };
3285
3286 /* ethtool interface */
3287
3288 static void tun_default_link_ksettings(struct net_device *dev,
3289                                        struct ethtool_link_ksettings *cmd)
3290 {
3291         ethtool_link_ksettings_zero_link_mode(cmd, supported);
3292         ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3293         cmd->base.speed         = SPEED_10;
3294         cmd->base.duplex        = DUPLEX_FULL;
3295         cmd->base.port          = PORT_TP;
3296         cmd->base.phy_address   = 0;
3297         cmd->base.autoneg       = AUTONEG_DISABLE;
3298 }
3299
3300 static int tun_get_link_ksettings(struct net_device *dev,
3301                                   struct ethtool_link_ksettings *cmd)
3302 {
3303         struct tun_struct *tun = netdev_priv(dev);
3304
3305         memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3306         return 0;
3307 }
3308
3309 static int tun_set_link_ksettings(struct net_device *dev,
3310                                   const struct ethtool_link_ksettings *cmd)
3311 {
3312         struct tun_struct *tun = netdev_priv(dev);
3313
3314         memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3315         return 0;
3316 }
3317
3318 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3319 {
3320         struct tun_struct *tun = netdev_priv(dev);
3321
3322         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3323         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3324
3325         switch (tun->flags & TUN_TYPE_MASK) {
3326         case IFF_TUN:
3327                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3328                 break;
3329         case IFF_TAP:
3330                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3331                 break;
3332         }
3333 }
3334
3335 static u32 tun_get_msglevel(struct net_device *dev)
3336 {
3337 #ifdef TUN_DEBUG
3338         struct tun_struct *tun = netdev_priv(dev);
3339         return tun->debug;
3340 #else
3341         return -EOPNOTSUPP;
3342 #endif
3343 }
3344
3345 static void tun_set_msglevel(struct net_device *dev, u32 value)
3346 {
3347 #ifdef TUN_DEBUG
3348         struct tun_struct *tun = netdev_priv(dev);
3349         tun->debug = value;
3350 #endif
3351 }
3352
3353 static int tun_get_coalesce(struct net_device *dev,
3354                             struct ethtool_coalesce *ec)
3355 {
3356         struct tun_struct *tun = netdev_priv(dev);
3357
3358         ec->rx_max_coalesced_frames = tun->rx_batched;
3359
3360         return 0;
3361 }
3362
3363 static int tun_set_coalesce(struct net_device *dev,
3364                             struct ethtool_coalesce *ec)
3365 {
3366         struct tun_struct *tun = netdev_priv(dev);
3367
3368         if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3369                 tun->rx_batched = NAPI_POLL_WEIGHT;
3370         else
3371                 tun->rx_batched = ec->rx_max_coalesced_frames;
3372
3373         return 0;
3374 }
3375
3376 static const struct ethtool_ops tun_ethtool_ops = {
3377         .get_drvinfo    = tun_get_drvinfo,
3378         .get_msglevel   = tun_get_msglevel,
3379         .set_msglevel   = tun_set_msglevel,
3380         .get_link       = ethtool_op_get_link,
3381         .get_ts_info    = ethtool_op_get_ts_info,
3382         .get_coalesce   = tun_get_coalesce,
3383         .set_coalesce   = tun_set_coalesce,
3384         .get_link_ksettings = tun_get_link_ksettings,
3385         .set_link_ksettings = tun_set_link_ksettings,
3386 };
3387
3388 static int tun_queue_resize(struct tun_struct *tun)
3389 {
3390         struct net_device *dev = tun->dev;
3391         struct tun_file *tfile;
3392         struct ptr_ring **rings;
3393         int n = tun->numqueues + tun->numdisabled;
3394         int ret, i;
3395
3396         rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3397         if (!rings)
3398                 return -ENOMEM;
3399
3400         for (i = 0; i < tun->numqueues; i++) {
3401                 tfile = rtnl_dereference(tun->tfiles[i]);
3402                 rings[i] = &tfile->tx_ring;
3403         }
3404         list_for_each_entry(tfile, &tun->disabled, next)
3405                 rings[i++] = &tfile->tx_ring;
3406
3407         ret = ptr_ring_resize_multiple(rings, n,
3408                                        dev->tx_queue_len, GFP_KERNEL,
3409                                        tun_ptr_free);
3410
3411         kfree(rings);
3412         return ret;
3413 }
3414
3415 static int tun_device_event(struct notifier_block *unused,
3416                             unsigned long event, void *ptr)
3417 {
3418         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3419         struct tun_struct *tun = netdev_priv(dev);
3420
3421         if (dev->rtnl_link_ops != &tun_link_ops)
3422                 return NOTIFY_DONE;
3423
3424         switch (event) {
3425         case NETDEV_CHANGE_TX_QUEUE_LEN:
3426                 if (tun_queue_resize(tun))
3427                         return NOTIFY_BAD;
3428                 break;
3429         default:
3430                 break;
3431         }
3432
3433         return NOTIFY_DONE;
3434 }
3435
3436 static struct notifier_block tun_notifier_block __read_mostly = {
3437         .notifier_call  = tun_device_event,
3438 };
3439
3440 static int __init tun_init(void)
3441 {
3442         int ret = 0;
3443
3444         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3445
3446         ret = rtnl_link_register(&tun_link_ops);
3447         if (ret) {
3448                 pr_err("Can't register link_ops\n");
3449                 goto err_linkops;
3450         }
3451
3452         ret = misc_register(&tun_miscdev);
3453         if (ret) {
3454                 pr_err("Can't register misc device %d\n", TUN_MINOR);
3455                 goto err_misc;
3456         }
3457
3458         ret = register_netdevice_notifier(&tun_notifier_block);
3459         if (ret) {
3460                 pr_err("Can't register netdevice notifier\n");
3461                 goto err_notifier;
3462         }
3463
3464         return  0;
3465
3466 err_notifier:
3467         misc_deregister(&tun_miscdev);
3468 err_misc:
3469         rtnl_link_unregister(&tun_link_ops);
3470 err_linkops:
3471         return ret;
3472 }
3473
3474 static void tun_cleanup(void)
3475 {
3476         misc_deregister(&tun_miscdev);
3477         rtnl_link_unregister(&tun_link_ops);
3478         unregister_netdevice_notifier(&tun_notifier_block);
3479 }
3480
3481 /* Get an underlying socket object from tun file.  Returns error unless file is
3482  * attached to a device.  The returned object works like a packet socket, it
3483  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
3484  * holding a reference to the file for as long as the socket is in use. */
3485 struct socket *tun_get_socket(struct file *file)
3486 {
3487         struct tun_file *tfile;
3488         if (file->f_op != &tun_fops)
3489                 return ERR_PTR(-EINVAL);
3490         tfile = file->private_data;
3491         if (!tfile)
3492                 return ERR_PTR(-EBADFD);
3493         return &tfile->socket;
3494 }
3495 EXPORT_SYMBOL_GPL(tun_get_socket);
3496
3497 struct ptr_ring *tun_get_tx_ring(struct file *file)
3498 {
3499         struct tun_file *tfile;
3500
3501         if (file->f_op != &tun_fops)
3502                 return ERR_PTR(-EINVAL);
3503         tfile = file->private_data;
3504         if (!tfile)
3505                 return ERR_PTR(-EBADFD);
3506         return &tfile->tx_ring;
3507 }
3508 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3509
3510 module_init(tun_init);
3511 module_exit(tun_cleanup);
3512 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3513 MODULE_AUTHOR(DRV_COPYRIGHT);
3514 MODULE_LICENSE("GPL");
3515 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3516 MODULE_ALIAS("devname:net/tun");