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_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
 117
 118 /* TUN device flags */
 119
 120 /* IFF_ATTACH_QUEUE is never stored in device flags,
 121  * overload it to mean fasync when stored there.
 122  */
 123 #define TUN_FASYNC      IFF_ATTACH_QUEUE
 124 /* High bits in flags field are unused. */
 125 #define TUN_VNET_LE     0x80000000
 126 #define TUN_VNET_BE     0x40000000
 127
 128 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
 129                       IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
 130
 131 #define GOODCOPY_LEN 128
 132
 133 #define FLT_EXACT_COUNT 8
 134 struct tap_filter {
 135         unsigned int    count;    /* Number of addrs. Zero means disabled */
 136         u32             mask[2];  /* Mask of the hashed addrs */
 137         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 138 };
 139
 140 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
 141  * to max number of VCPUs in guest. */
 142 #define MAX_TAP_QUEUES 256
 143 #define MAX_TAP_FLOWS  4096
 144
 145 #define TUN_FLOW_EXPIRE (3 * HZ)
 146
 147 struct tun_pcpu_stats {
 148         u64 rx_packets;
 149         u64 rx_bytes;
 150         u64 tx_packets;
 151         u64 tx_bytes;
 152         struct u64_stats_sync syncp;
 153         u32 rx_dropped;
 154         u32 tx_dropped;
 155         u32 rx_frame_errors;
 156 };
 157
 158 /* A tun_file connects an open character device to a tuntap netdevice. It
 159  * also contains all socket related structures (except sock_fprog and tap_filter)
 160  * to serve as one transmit queue for tuntap device. The sock_fprog and
 161  * tap_filter were kept in tun_struct since they were used for filtering for the
 162  * netdevice not for a specific queue (at least I didn't see the requirement for
 163  * this).
 164  *
 165  * RCU usage:
 166  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
 167  * other can only be read while rcu_read_lock or rtnl_lock is held.
 168  */
 169 struct tun_file {
 170         struct sock sk;
 171         struct socket socket;
 172         struct socket_wq wq;
 173         struct tun_struct __rcu *tun;
 174         struct fasync_struct *fasync;
 175         /* only used for fasnyc */
 176         unsigned int flags;
 177         union {
 178                 u16 queue_index;
 179                 unsigned int ifindex;
 180         };
 181         struct napi_struct napi;
 182         bool napi_enabled;
 183         bool napi_frags_enabled;
 184         struct mutex napi_mutex;        /* Protects access to the above napi */
 185         struct list_head next;
 186         struct tun_struct *detached;
 187         struct ptr_ring tx_ring;
 188         struct xdp_rxq_info xdp_rxq;
 189 };
 190
 191 struct tun_flow_entry {
 192         struct hlist_node hash_link;
 193         struct rcu_head rcu;
 194         struct tun_struct *tun;
 195
 196         u32 rxhash;
 197         u32 rps_rxhash;
 198         int queue_index;
 199         unsigned long updated;
 200 };
 201
 202 #define TUN_NUM_FLOW_ENTRIES 1024
 203 #define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
 204
 205 struct tun_prog {
 206         struct rcu_head rcu;
 207         struct bpf_prog *prog;
 208 };
 209
 210 /* Since the socket were moved to tun_file, to preserve the behavior of persist
 211  * device, socket filter, sndbuf and vnet header size were restore when the
 212  * file were attached to a persist device.
 213  */
 214 struct tun_struct {
 215         struct tun_file __rcu   *tfiles[MAX_TAP_QUEUES];
 216         unsigned int            numqueues;
 217         unsigned int            flags;
 218         kuid_t                  owner;
 219         kgid_t                  group;
 220
 221         struct net_device       *dev;
 222         netdev_features_t       set_features;
 223 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 224                           NETIF_F_TSO6)
 225
 226         int                     align;
 227         int                     vnet_hdr_sz;
 228         int                     sndbuf;
 229         struct tap_filter       txflt;
 230         struct sock_fprog       fprog;
 231         /* protected by rtnl lock */
 232         bool                    filter_attached;
 233 #ifdef TUN_DEBUG
 234         int debug;
 235 #endif
 236         spinlock_t lock;
 237         struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 238         struct timer_list flow_gc_timer;
 239         unsigned long ageing_time;
 240         unsigned int numdisabled;
 241         struct list_head disabled;
 242         void *security;
 243         u32 flow_count;
 244         u32 rx_batched;
 245         struct tun_pcpu_stats __percpu *pcpu_stats;
 246         struct bpf_prog __rcu *xdp_prog;
 247         struct tun_prog __rcu *steering_prog;
 248         struct tun_prog __rcu *filter_prog;
 249         struct ethtool_link_ksettings link_ksettings;
 250 };
 251
 252 struct veth {
 253         __be16 h_vlan_proto;
 254         __be16 h_vlan_TCI;
 255 };
 256
 257 bool tun_is_xdp_frame(void *ptr)
 258 {
 259         return (unsigned long)ptr & TUN_XDP_FLAG;
 260 }
 261 EXPORT_SYMBOL(tun_is_xdp_frame);
 262
 263 void *tun_xdp_to_ptr(void *ptr)
 264 {
 265         return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
 266 }
 267 EXPORT_SYMBOL(tun_xdp_to_ptr);
 268
 269 void *tun_ptr_to_xdp(void *ptr)
 270 {
 271         return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
 272 }
 273 EXPORT_SYMBOL(tun_ptr_to_xdp);
 274
 275 static int tun_napi_receive(struct napi_struct *napi, int budget)
 276 {
 277         struct tun_file *tfile = container_of(napi, struct tun_file, napi);
 278         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
 279         struct sk_buff_head process_queue;
 280         struct sk_buff *skb;
 281         int received = 0;
 282
 283         __skb_queue_head_init(&process_queue);
 284
 285         spin_lock(&queue->lock);
 286         skb_queue_splice_tail_init(queue, &process_queue);
 287         spin_unlock(&queue->lock);
 288
 289         while (received < budget && (skb = __skb_dequeue(&process_queue))) {
 290                 napi_gro_receive(napi, skb);
 291                 ++received;
 292         }
 293
 294         if (!skb_queue_empty(&process_queue)) {
 295                 spin_lock(&queue->lock);
 296                 skb_queue_splice(&process_queue, queue);
 297                 spin_unlock(&queue->lock);
 298         }
 299
 300         return received;
 301 }
 302
 303 static int tun_napi_poll(struct napi_struct *napi, int budget)
 304 {
 305         unsigned int received;
 306
 307         received = tun_napi_receive(napi, budget);
 308
 309         if (received < budget)
 310                 napi_complete_done(napi, received);
 311
 312         return received;
 313 }
 314
 315 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
 316                           bool napi_en, bool napi_frags)
 317 {
 318         tfile->napi_enabled = napi_en;
 319         tfile->napi_frags_enabled = napi_en && napi_frags;
 320         if (napi_en) {
 321                 netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
 322                                NAPI_POLL_WEIGHT);
 323                 napi_enable(&tfile->napi);
 324         }
 325 }
 326
 327 static void tun_napi_disable(struct tun_file *tfile)
 328 {
 329         if (tfile->napi_enabled)
 330                 napi_disable(&tfile->napi);
 331 }
 332
 333 static void tun_napi_del(struct tun_file *tfile)
 334 {
 335         if (tfile->napi_enabled)
 336                 netif_napi_del(&tfile->napi);
 337 }
 338
 339 static bool tun_napi_frags_enabled(const struct tun_file *tfile)
 340 {
 341         return tfile->napi_frags_enabled;
 342 }
 343
 344 #ifdef CONFIG_TUN_VNET_CROSS_LE
 345 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 346 {
 347         return tun->flags & TUN_VNET_BE ? false :
 348                 virtio_legacy_is_little_endian();
 349 }
 350
 351 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 352 {
 353         int be = !!(tun->flags & TUN_VNET_BE);
 354
 355         if (put_user(be, argp))
 356                 return -EFAULT;
 357
 358         return 0;
 359 }
 360
 361 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 362 {
 363         int be;
 364
 365         if (get_user(be, argp))
 366                 return -EFAULT;
 367
 368         if (be)
 369                 tun->flags |= TUN_VNET_BE;
 370         else
 371                 tun->flags &= ~TUN_VNET_BE;
 372
 373         return 0;
 374 }
 375 #else
 376 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 377 {
 378         return virtio_legacy_is_little_endian();
 379 }
 380
 381 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 382 {
 383         return -EINVAL;
 384 }
 385
 386 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 387 {
 388         return -EINVAL;
 389 }
 390 #endif /* CONFIG_TUN_VNET_CROSS_LE */
 391
 392 static inline bool tun_is_little_endian(struct tun_struct *tun)
 393 {
 394         return tun->flags & TUN_VNET_LE ||
 395                 tun_legacy_is_little_endian(tun);
 396 }
 397
 398 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
 399 {
 400         return __virtio16_to_cpu(tun_is_little_endian(tun), val);
 401 }
 402
 403 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
 404 {
 405         return __cpu_to_virtio16(tun_is_little_endian(tun), val);
 406 }
 407
 408 static inline u32 tun_hashfn(u32 rxhash)
 409 {
 410         return rxhash & TUN_MASK_FLOW_ENTRIES;
 411 }
 412
 413 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 414 {
 415         struct tun_flow_entry *e;
 416
 417         hlist_for_each_entry_rcu(e, head, hash_link) {
 418                 if (e->rxhash == rxhash)
 419                         return e;
 420         }
 421         return NULL;
 422 }
 423
 424 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 425                                               struct hlist_head *head,
 426                                               u32 rxhash, u16 queue_index)
 427 {
 428         struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 429
 430         if (e) {
 431                 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 432                           rxhash, queue_index);
 433                 e->updated = jiffies;
 434                 e->rxhash = rxhash;
 435                 e->rps_rxhash = 0;
 436                 e->queue_index = queue_index;
 437                 e->tun = tun;
 438                 hlist_add_head_rcu(&e->hash_link, head);
 439                 ++tun->flow_count;
 440         }
 441         return e;
 442 }
 443
 444 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 445 {
 446         tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 447                   e->rxhash, e->queue_index);
 448         hlist_del_rcu(&e->hash_link);
 449         kfree_rcu(e, rcu);
 450         --tun->flow_count;
 451 }
 452
 453 static void tun_flow_flush(struct tun_struct *tun)
 454 {
 455         int i;
 456
 457         spin_lock_bh(&tun->lock);
 458         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 459                 struct tun_flow_entry *e;
 460                 struct hlist_node *n;
 461
 462                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 463                         tun_flow_delete(tun, e);
 464         }
 465         spin_unlock_bh(&tun->lock);
 466 }
 467
 468 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 469 {
 470         int i;
 471
 472         spin_lock_bh(&tun->lock);
 473         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 474                 struct tun_flow_entry *e;
 475                 struct hlist_node *n;
 476
 477                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 478                         if (e->queue_index == queue_index)
 479                                 tun_flow_delete(tun, e);
 480                 }
 481         }
 482         spin_unlock_bh(&tun->lock);
 483 }
 484
 485 static void tun_flow_cleanup(struct timer_list *t)
 486 {
 487         struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
 488         unsigned long delay = tun->ageing_time;
 489         unsigned long next_timer = jiffies + delay;
 490         unsigned long count = 0;
 491         int i;
 492
 493         tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 494
 495         spin_lock(&tun->lock);
 496         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 497                 struct tun_flow_entry *e;
 498                 struct hlist_node *n;
 499
 500                 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 501                         unsigned long this_timer;
 502
 503                         this_timer = e->updated + delay;
 504                         if (time_before_eq(this_timer, jiffies)) {
 505                                 tun_flow_delete(tun, e);
 506                                 continue;
 507                         }
 508                         count++;
 509                         if (time_before(this_timer, next_timer))
 510                                 next_timer = this_timer;
 511                 }
 512         }
 513
 514         if (count)
 515                 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 516         spin_unlock(&tun->lock);
 517 }
 518
 519 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 520                             struct tun_file *tfile)
 521 {
 522         struct hlist_head *head;
 523         struct tun_flow_entry *e;
 524         unsigned long delay = tun->ageing_time;
 525         u16 queue_index = tfile->queue_index;
 526
 527         if (!rxhash)
 528                 return;
 529         else
 530                 head = &tun->flows[tun_hashfn(rxhash)];
 531
 532         rcu_read_lock();
 533
 534         e = tun_flow_find(head, rxhash);
 535         if (likely(e)) {
 536                 /* TODO: keep queueing to old queue until it's empty? */
 537                 e->queue_index = queue_index;
 538                 e->updated = jiffies;
 539                 sock_rps_record_flow_hash(e->rps_rxhash);
 540         } else {
 541                 spin_lock_bh(&tun->lock);
 542                 if (!tun_flow_find(head, rxhash) &&
 543                     tun->flow_count < MAX_TAP_FLOWS)
 544                         tun_flow_create(tun, head, rxhash, queue_index);
 545
 546                 if (!timer_pending(&tun->flow_gc_timer))
 547                         mod_timer(&tun->flow_gc_timer,
 548                                   round_jiffies_up(jiffies + delay));
 549                 spin_unlock_bh(&tun->lock);
 550         }
 551
 552         rcu_read_unlock();
 553 }
 554
 555 /**
 556  * Save the hash received in the stack receive path and update the
 557  * flow_hash table accordingly.
 558  */
 559 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
 560 {
 561         if (unlikely(e->rps_rxhash != hash))
 562                 e->rps_rxhash = hash;
 563 }
 564
 565 /* We try to identify a flow through its rxhash. The reason that
 566  * we do not check rxq no. is because some cards(e.g 82599), chooses
 567  * the rxq based on the txq where the last packet of the flow comes. As
 568  * the userspace application move between processors, we may get a
 569  * different rxq no. here.
 570  */
 571 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 572 {
 573         struct tun_flow_entry *e;
 574         u32 txq = 0;
 575         u32 numqueues = 0;
 576
 577         numqueues = READ_ONCE(tun->numqueues);
 578
 579         txq = __skb_get_hash_symmetric(skb);
 580         e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 581         if (e) {
 582                 tun_flow_save_rps_rxhash(e, txq);
 583                 txq = e->queue_index;
 584         } else {
 585                 /* use multiply and shift instead of expensive divide */
 586                 txq = ((u64)txq * numqueues) >> 32;
 587         }
 588
 589         return txq;
 590 }
 591
 592 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
 593 {
 594         struct tun_prog *prog;
 595         u16 ret = 0;
 596
 597         prog = rcu_dereference(tun->steering_prog);
 598         if (prog)
 599                 ret = bpf_prog_run_clear_cb(prog->prog, skb);
 600
 601         return ret % tun->numqueues;
 602 }
 603
 604 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
 605                             struct net_device *sb_dev,
 606                             select_queue_fallback_t fallback)
 607 {
 608         struct tun_struct *tun = netdev_priv(dev);
 609         u16 ret;
 610
 611         rcu_read_lock();
 612         if (rcu_dereference(tun->steering_prog))
 613                 ret = tun_ebpf_select_queue(tun, skb);
 614         else
 615                 ret = tun_automq_select_queue(tun, skb);
 616         rcu_read_unlock();
 617
 618         return ret;
 619 }
 620
 621 static inline bool tun_not_capable(struct tun_struct *tun)
 622 {
 623         const struct cred *cred = current_cred();
 624         struct net *net = dev_net(tun->dev);
 625
 626         return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 627                   (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 628                 !ns_capable(net->user_ns, CAP_NET_ADMIN);
 629 }
 630
 631 static void tun_set_real_num_queues(struct tun_struct *tun)
 632 {
 633         netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 634         netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 635 }
 636
 637 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 638 {
 639         tfile->detached = tun;
 640         list_add_tail(&tfile->next, &tun->disabled);
 641         ++tun->numdisabled;
 642 }
 643
 644 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 645 {
 646         struct tun_struct *tun = tfile->detached;
 647
 648         tfile->detached = NULL;
 649         list_del_init(&tfile->next);
 650         --tun->numdisabled;
 651         return tun;
 652 }
 653
 654 void tun_ptr_free(void *ptr)
 655 {
 656         if (!ptr)
 657                 return;
 658         if (tun_is_xdp_frame(ptr)) {
 659                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
 660
 661                 xdp_return_frame(xdpf);
 662         } else {
 663                 __skb_array_destroy_skb(ptr);
 664         }
 665 }
 666 EXPORT_SYMBOL_GPL(tun_ptr_free);
 667
 668 static void tun_queue_purge(struct tun_file *tfile)
 669 {
 670         void *ptr;
 671
 672         while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
 673                 tun_ptr_free(ptr);
 674
 675         skb_queue_purge(&tfile->sk.sk_write_queue);
 676         skb_queue_purge(&tfile->sk.sk_error_queue);
 677 }
 678
 679 static void __tun_detach(struct tun_file *tfile, bool clean)
 680 {
 681         struct tun_file *ntfile;
 682         struct tun_struct *tun;
 683
 684         tun = rtnl_dereference(tfile->tun);
 685
 686         if (tun && clean) {
 687                 tun_napi_disable(tfile);
 688                 tun_napi_del(tfile);
 689         }
 690
 691         if (tun && !tfile->detached) {
 692                 u16 index = tfile->queue_index;
 693                 BUG_ON(index >= tun->numqueues);
 694
 695                 rcu_assign_pointer(tun->tfiles[index],
 696                                    tun->tfiles[tun->numqueues - 1]);
 697                 ntfile = rtnl_dereference(tun->tfiles[index]);
 698                 ntfile->queue_index = index;
 699
 700                 --tun->numqueues;
 701                 if (clean) {
 702                         RCU_INIT_POINTER(tfile->tun, NULL);
 703                         sock_put(&tfile->sk);
 704                 } else
 705                         tun_disable_queue(tun, tfile);
 706
 707                 synchronize_net();
 708                 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 709                 /* Drop read queue */
 710                 tun_queue_purge(tfile);
 711                 tun_set_real_num_queues(tun);
 712         } else if (tfile->detached && clean) {
 713                 tun = tun_enable_queue(tfile);
 714                 sock_put(&tfile->sk);
 715         }
 716
 717         if (clean) {
 718                 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 719                         netif_carrier_off(tun->dev);
 720
 721                         if (!(tun->flags & IFF_PERSIST) &&
 722                             tun->dev->reg_state == NETREG_REGISTERED)
 723                                 unregister_netdevice(tun->dev);
 724                 }
 725                 if (tun)
 726                         xdp_rxq_info_unreg(&tfile->xdp_rxq);
 727                 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
 728                 sock_put(&tfile->sk);
 729         }
 730 }
 731
 732 static void tun_detach(struct tun_file *tfile, bool clean)
 733 {
 734         struct tun_struct *tun;
 735         struct net_device *dev;
 736
 737         rtnl_lock();
 738         tun = rtnl_dereference(tfile->tun);
 739         dev = tun ? tun->dev : NULL;
 740         __tun_detach(tfile, clean);
 741         if (dev)
 742                 netdev_state_change(dev);
 743         rtnl_unlock();
 744 }
 745
 746 static void tun_detach_all(struct net_device *dev)
 747 {
 748         struct tun_struct *tun = netdev_priv(dev);
 749         struct tun_file *tfile, *tmp;
 750         int i, n = tun->numqueues;
 751
 752         for (i = 0; i < n; i++) {
 753                 tfile = rtnl_dereference(tun->tfiles[i]);
 754                 BUG_ON(!tfile);
 755                 tun_napi_disable(tfile);
 756                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 757                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 758                 RCU_INIT_POINTER(tfile->tun, NULL);
 759                 --tun->numqueues;
 760         }
 761         list_for_each_entry(tfile, &tun->disabled, next) {
 762                 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
 763                 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 764                 RCU_INIT_POINTER(tfile->tun, NULL);
 765         }
 766         BUG_ON(tun->numqueues != 0);
 767
 768         synchronize_net();
 769         for (i = 0; i < n; i++) {
 770                 tfile = rtnl_dereference(tun->tfiles[i]);
 771                 tun_napi_del(tfile);
 772                 /* Drop read queue */
 773                 tun_queue_purge(tfile);
 774                 xdp_rxq_info_unreg(&tfile->xdp_rxq);
 775                 sock_put(&tfile->sk);
 776         }
 777         list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 778                 tun_enable_queue(tfile);
 779                 tun_queue_purge(tfile);
 780                 xdp_rxq_info_unreg(&tfile->xdp_rxq);
 781                 sock_put(&tfile->sk);
 782         }
 783         BUG_ON(tun->numdisabled != 0);
 784
 785         if (tun->flags & IFF_PERSIST)
 786                 module_put(THIS_MODULE);
 787 }
 788
 789 static int tun_attach(struct tun_struct *tun, struct file *file,
 790                       bool skip_filter, bool napi, bool napi_frags)
 791 {
 792         struct tun_file *tfile = file->private_data;
 793         struct net_device *dev = tun->dev;
 794         int err;
 795
 796         err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 797         if (err < 0)
 798                 goto out;
 799
 800         err = -EINVAL;
 801         if (rtnl_dereference(tfile->tun) && !tfile->detached)
 802                 goto out;
 803
 804         err = -EBUSY;
 805         if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
 806                 goto out;
 807
 808         err = -E2BIG;
 809         if (!tfile->detached &&
 810             tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 811                 goto out;
 812
 813         err = 0;
 814
 815         /* Re-attach the filter to persist device */
 816         if (!skip_filter && (tun->filter_attached == true)) {
 817                 lock_sock(tfile->socket.sk);
 818                 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 819                 release_sock(tfile->socket.sk);
 820                 if (!err)
 821                         goto out;
 822         }
 823
 824         if (!tfile->detached &&
 825             ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
 826                             GFP_KERNEL, tun_ptr_free)) {
 827                 err = -ENOMEM;
 828                 goto out;
 829         }
 830
 831         tfile->queue_index = tun->numqueues;
 832         tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
 833
 834         if (tfile->detached) {
 835                 /* Re-attach detached tfile, updating XDP queue_index */
 836                 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
 837
 838                 if (tfile->xdp_rxq.queue_index    != tfile->queue_index)
 839                         tfile->xdp_rxq.queue_index = tfile->queue_index;
 840         } else {
 841                 /* Setup XDP RX-queue info, for new tfile getting attached */
 842                 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
 843                                        tun->dev, tfile->queue_index);
 844                 if (err < 0)
 845                         goto out;
 846                 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
 847                                                  MEM_TYPE_PAGE_SHARED, NULL);
 848                 if (err < 0) {
 849                         xdp_rxq_info_unreg(&tfile->xdp_rxq);
 850                         goto out;
 851                 }
 852                 err = 0;
 853         }
 854
 855         rcu_assign_pointer(tfile->tun, tun);
 856         rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 857         tun->numqueues++;
 858
 859         if (tfile->detached) {
 860                 tun_enable_queue(tfile);
 861         } else {
 862                 sock_hold(&tfile->sk);
 863                 tun_napi_init(tun, tfile, napi, napi_frags);
 864         }
 865
 866         if (rtnl_dereference(tun->xdp_prog))
 867                 sock_set_flag(&tfile->sk, SOCK_XDP);
 868
 869         tun_set_real_num_queues(tun);
 870
 871         /* device is allowed to go away first, so no need to hold extra
 872          * refcnt.
 873          */
 874
 875 out:
 876         return err;
 877 }
 878
 879 static struct tun_struct *tun_get(struct tun_file *tfile)
 880 {
 881         struct tun_struct *tun;
 882
 883         rcu_read_lock();
 884         tun = rcu_dereference(tfile->tun);
 885         if (tun)
 886                 dev_hold(tun->dev);
 887         rcu_read_unlock();
 888
 889         return tun;
 890 }
 891
 892 static void tun_put(struct tun_struct *tun)
 893 {
 894         dev_put(tun->dev);
 895 }
 896
 897 /* TAP filtering */
 898 static void addr_hash_set(u32 *mask, const u8 *addr)
 899 {
 900         int n = ether_crc(ETH_ALEN, addr) >> 26;
 901         mask[n >> 5] |= (1 << (n & 31));
 902 }
 903
 904 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 905 {
 906         int n = ether_crc(ETH_ALEN, addr) >> 26;
 907         return mask[n >> 5] & (1 << (n & 31));
 908 }
 909
 910 static int update_filter(struct tap_filter *filter, void __user *arg)
 911 {
 912         struct { u8 u[ETH_ALEN]; } *addr;
 913         struct tun_filter uf;
 914         int err, alen, n, nexact;
 915
 916         if (copy_from_user(&uf, arg, sizeof(uf)))
 917                 return -EFAULT;
 918
 919         if (!uf.count) {
 920                 /* Disabled */
 921                 filter->count = 0;
 922                 return 0;
 923         }
 924
 925         alen = ETH_ALEN * uf.count;
 926         addr = memdup_user(arg + sizeof(uf), alen);
 927         if (IS_ERR(addr))
 928                 return PTR_ERR(addr);
 929
 930         /* The filter is updated without holding any locks. Which is
 931          * perfectly safe. We disable it first and in the worst
 932          * case we'll accept a few undesired packets. */
 933         filter->count = 0;
 934         wmb();
 935
 936         /* Use first set of addresses as an exact filter */
 937         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 938                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 939
 940         nexact = n;
 941
 942         /* Remaining multicast addresses are hashed,
 943          * unicast will leave the filter disabled. */
 944         memset(filter->mask, 0, sizeof(filter->mask));
 945         for (; n < uf.count; n++) {
 946                 if (!is_multicast_ether_addr(addr[n].u)) {
 947                         err = 0; /* no filter */
 948                         goto free_addr;
 949                 }
 950                 addr_hash_set(filter->mask, addr[n].u);
 951         }
 952
 953         /* For ALLMULTI just set the mask to all ones.
 954          * This overrides the mask populated above. */
 955         if ((uf.flags & TUN_FLT_ALLMULTI))
 956                 memset(filter->mask, ~0, sizeof(filter->mask));
 957
 958         /* Now enable the filter */
 959         wmb();
 960         filter->count = nexact;
 961
 962         /* Return the number of exact filters */
 963         err = nexact;
 964 free_addr:
 965         kfree(addr);
 966         return err;
 967 }
 968
 969 /* Returns: 0 - drop, !=0 - accept */
 970 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 971 {
 972         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 973          * at this point. */
 974         struct ethhdr *eh = (struct ethhdr *) skb->data;
 975         int i;
 976
 977         /* Exact match */
 978         for (i = 0; i < filter->count; i++)
 979                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 980                         return 1;
 981
 982         /* Inexact match (multicast only) */
 983         if (is_multicast_ether_addr(eh->h_dest))
 984                 return addr_hash_test(filter->mask, eh->h_dest);
 985
 986         return 0;
 987 }
 988
 989 /*
 990  * Checks whether the packet is accepted or not.
 991  * Returns: 0 - drop, !=0 - accept
 992  */
 993 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 994 {
 995         if (!filter->count)
 996                 return 1;
 997
 998         return run_filter(filter, skb);
 999 }
1000
1001 /* Network device part of the driver */
1002
1003 static const struct ethtool_ops tun_ethtool_ops;
1004
1005 /* Net device detach from fd. */
1006 static void tun_net_uninit(struct net_device *dev)
1007 {
1008         tun_detach_all(dev);
1009 }
1010
1011 /* Net device open. */
1012 static int tun_net_open(struct net_device *dev)
1013 {
1014         struct tun_struct *tun = netdev_priv(dev);
1015         int i;
1016
1017         netif_tx_start_all_queues(dev);
1018
1019         for (i = 0; i < tun->numqueues; i++) {
1020                 struct tun_file *tfile;
1021
1022                 tfile = rtnl_dereference(tun->tfiles[i]);
1023                 tfile->socket.sk->sk_write_space(tfile->socket.sk);
1024         }
1025
1026         return 0;
1027 }
1028
1029 /* Net device close. */
1030 static int tun_net_close(struct net_device *dev)
1031 {
1032         netif_tx_stop_all_queues(dev);
1033         return 0;
1034 }
1035
1036 /* Net device start xmit */
1037 static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1038 {
1039 #ifdef CONFIG_RPS
1040         if (tun->numqueues == 1 && static_key_false(&rps_needed)) {
1041                 /* Select queue was not called for the skbuff, so we extract the
1042                  * RPS hash and save it into the flow_table here.
1043                  */
1044                 struct tun_flow_entry *e;
1045                 __u32 rxhash;
1046
1047                 rxhash = __skb_get_hash_symmetric(skb);
1048                 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
1049                 if (e)
1050                         tun_flow_save_rps_rxhash(e, rxhash);
1051         }
1052 #endif
1053 }
1054
1055 static unsigned int run_ebpf_filter(struct tun_struct *tun,
1056                                     struct sk_buff *skb,
1057                                     int len)
1058 {
1059         struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1060
1061         if (prog)
1062                 len = bpf_prog_run_clear_cb(prog->prog, skb);
1063
1064         return len;
1065 }
1066
1067 /* Net device start xmit */
1068 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1069 {
1070         struct tun_struct *tun = netdev_priv(dev);
1071         int txq = skb->queue_mapping;
1072         struct tun_file *tfile;
1073         int len = skb->len;
1074
1075         rcu_read_lock();
1076         tfile = rcu_dereference(tun->tfiles[txq]);
1077
1078         /* Drop packet if interface is not attached */
1079         if (txq >= tun->numqueues)
1080                 goto drop;
1081
1082         if (!rcu_dereference(tun->steering_prog))
1083                 tun_automq_xmit(tun, skb);
1084
1085         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
1086
1087         BUG_ON(!tfile);
1088
1089         /* Drop if the filter does not like it.
1090          * This is a noop if the filter is disabled.
1091          * Filter can be enabled only for the TAP devices. */
1092         if (!check_filter(&tun->txflt, skb))
1093                 goto drop;
1094
1095         if (tfile->socket.sk->sk_filter &&
1096             sk_filter(tfile->socket.sk, skb))
1097                 goto drop;
1098
1099         len = run_ebpf_filter(tun, skb, len);
1100         if (len == 0 || pskb_trim(skb, len))
1101                 goto drop;
1102
1103         if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1104                 goto drop;
1105
1106         skb_tx_timestamp(skb);
1107
1108         /* Orphan the skb - required as we might hang on to it
1109          * for indefinite time.
1110          */
1111         skb_orphan(skb);
1112
1113         nf_reset(skb);
1114
1115         if (ptr_ring_produce(&tfile->tx_ring, skb))
1116                 goto drop;
1117
1118         /* Notify and wake up reader process */
1119         if (tfile->flags & TUN_FASYNC)
1120                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1121         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1122
1123         rcu_read_unlock();
1124         return NETDEV_TX_OK;
1125
1126 drop:
1127         this_cpu_inc(tun->pcpu_stats->tx_dropped);
1128         skb_tx_error(skb);
1129         kfree_skb(skb);
1130         rcu_read_unlock();
1131         return NET_XMIT_DROP;
1132 }
1133
1134 static void tun_net_mclist(struct net_device *dev)
1135 {
1136         /*
1137          * This callback is supposed to deal with mc filter in
1138          * _rx_ path and has nothing to do with the _tx_ path.
1139          * In rx path we always accept everything userspace gives us.
1140          */
1141 }
1142
1143 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1144         netdev_features_t features)
1145 {
1146         struct tun_struct *tun = netdev_priv(dev);
1147
1148         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1149 }
1150
1151 static void tun_set_headroom(struct net_device *dev, int new_hr)
1152 {
1153         struct tun_struct *tun = netdev_priv(dev);
1154
1155         if (new_hr < NET_SKB_PAD)
1156                 new_hr = NET_SKB_PAD;
1157
1158         tun->align = new_hr;
1159 }
1160
1161 static void
1162 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1163 {
1164         u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1165         struct tun_struct *tun = netdev_priv(dev);
1166         struct tun_pcpu_stats *p;
1167         int i;
1168
1169         for_each_possible_cpu(i) {
1170                 u64 rxpackets, rxbytes, txpackets, txbytes;
1171                 unsigned int start;
1172
1173                 p = per_cpu_ptr(tun->pcpu_stats, i);
1174                 do {
1175                         start = u64_stats_fetch_begin(&p->syncp);
1176                         rxpackets       = p->rx_packets;
1177                         rxbytes         = p->rx_bytes;
1178                         txpackets       = p->tx_packets;
1179                         txbytes         = p->tx_bytes;
1180                 } while (u64_stats_fetch_retry(&p->syncp, start));
1181
1182                 stats->rx_packets       += rxpackets;
1183                 stats->rx_bytes         += rxbytes;
1184                 stats->tx_packets       += txpackets;
1185                 stats->tx_bytes         += txbytes;
1186
1187                 /* u32 counters */
1188                 rx_dropped      += p->rx_dropped;
1189                 rx_frame_errors += p->rx_frame_errors;
1190                 tx_dropped      += p->tx_dropped;
1191         }
1192         stats->rx_dropped  = rx_dropped;
1193         stats->rx_frame_errors = rx_frame_errors;
1194         stats->tx_dropped = tx_dropped;
1195 }
1196
1197 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1198                        struct netlink_ext_ack *extack)
1199 {
1200         struct tun_struct *tun = netdev_priv(dev);
1201         struct tun_file *tfile;
1202         struct bpf_prog *old_prog;
1203         int i;
1204
1205         old_prog = rtnl_dereference(tun->xdp_prog);
1206         rcu_assign_pointer(tun->xdp_prog, prog);
1207         if (old_prog)
1208                 bpf_prog_put(old_prog);
1209
1210         for (i = 0; i < tun->numqueues; i++) {
1211                 tfile = rtnl_dereference(tun->tfiles[i]);
1212                 if (prog)
1213                         sock_set_flag(&tfile->sk, SOCK_XDP);
1214                 else
1215                         sock_reset_flag(&tfile->sk, SOCK_XDP);
1216         }
1217         list_for_each_entry(tfile, &tun->disabled, next) {
1218                 if (prog)
1219                         sock_set_flag(&tfile->sk, SOCK_XDP);
1220                 else
1221                         sock_reset_flag(&tfile->sk, SOCK_XDP);
1222         }
1223
1224         return 0;
1225 }
1226
1227 static u32 tun_xdp_query(struct net_device *dev)
1228 {
1229         struct tun_struct *tun = netdev_priv(dev);
1230         const struct bpf_prog *xdp_prog;
1231
1232         xdp_prog = rtnl_dereference(tun->xdp_prog);
1233         if (xdp_prog)
1234                 return xdp_prog->aux->id;
1235
1236         return 0;
1237 }
1238
1239 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1240 {
1241         switch (xdp->command) {
1242         case XDP_SETUP_PROG:
1243                 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1244         case XDP_QUERY_PROG:
1245                 xdp->prog_id = tun_xdp_query(dev);
1246                 return 0;
1247         default:
1248                 return -EINVAL;
1249         }
1250 }
1251
1252 static const struct net_device_ops tun_netdev_ops = {
1253         .ndo_uninit             = tun_net_uninit,
1254         .ndo_open               = tun_net_open,
1255         .ndo_stop               = tun_net_close,
1256         .ndo_start_xmit         = tun_net_xmit,
1257         .ndo_fix_features       = tun_net_fix_features,
1258         .ndo_select_queue       = tun_select_queue,
1259         .ndo_set_rx_headroom    = tun_set_headroom,
1260         .ndo_get_stats64        = tun_net_get_stats64,
1261 };
1262
1263 static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1264 {
1265         /* Notify and wake up reader process */
1266         if (tfile->flags & TUN_FASYNC)
1267                 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1268         tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1269 }
1270
1271 static int tun_xdp_xmit(struct net_device *dev, int n,
1272                         struct xdp_frame **frames, u32 flags)
1273 {
1274         struct tun_struct *tun = netdev_priv(dev);
1275         struct tun_file *tfile;
1276         u32 numqueues;
1277         int drops = 0;
1278         int cnt = n;
1279         int i;
1280
1281         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1282                 return -EINVAL;
1283
1284         rcu_read_lock();
1285
1286         numqueues = READ_ONCE(tun->numqueues);
1287         if (!numqueues) {
1288                 rcu_read_unlock();
1289                 return -ENXIO; /* Caller will free/return all frames */
1290         }
1291
1292         tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1293                                             numqueues]);
1294
1295         spin_lock(&tfile->tx_ring.producer_lock);
1296         for (i = 0; i < n; i++) {
1297                 struct xdp_frame *xdp = frames[i];
1298                 /* Encode the XDP flag into lowest bit for consumer to differ
1299                  * XDP buffer from sk_buff.
1300                  */
1301                 void *frame = tun_xdp_to_ptr(xdp);
1302
1303                 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1304                         this_cpu_inc(tun->pcpu_stats->tx_dropped);
1305                         xdp_return_frame_rx_napi(xdp);
1306                         drops++;
1307                 }
1308         }
1309         spin_unlock(&tfile->tx_ring.producer_lock);
1310
1311         if (flags & XDP_XMIT_FLUSH)
1312                 __tun_xdp_flush_tfile(tfile);
1313
1314         rcu_read_unlock();
1315         return cnt - drops;
1316 }
1317
1318 static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1319 {
1320         struct xdp_frame *frame = convert_to_xdp_frame(xdp);
1321
1322         if (unlikely(!frame))
1323                 return -EOVERFLOW;
1324
1325         return tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1326 }
1327
1328 static const struct net_device_ops tap_netdev_ops = {
1329         .ndo_uninit             = tun_net_uninit,
1330         .ndo_open               = tun_net_open,
1331         .ndo_stop               = tun_net_close,
1332         .ndo_start_xmit         = tun_net_xmit,
1333         .ndo_fix_features       = tun_net_fix_features,
1334         .ndo_set_rx_mode        = tun_net_mclist,
1335         .ndo_set_mac_address    = eth_mac_addr,
1336         .ndo_validate_addr      = eth_validate_addr,
1337         .ndo_select_queue       = tun_select_queue,
1338         .ndo_features_check     = passthru_features_check,
1339         .ndo_set_rx_headroom    = tun_set_headroom,
1340         .ndo_get_stats64        = tun_net_get_stats64,
1341         .ndo_bpf                = tun_xdp,
1342         .ndo_xdp_xmit           = tun_xdp_xmit,
1343 };
1344
1345 static void tun_flow_init(struct tun_struct *tun)
1346 {
1347         int i;
1348
1349         for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1350                 INIT_HLIST_HEAD(&tun->flows[i]);
1351
1352         tun->ageing_time = TUN_FLOW_EXPIRE;
1353         timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1354         mod_timer(&tun->flow_gc_timer,
1355                   round_jiffies_up(jiffies + tun->ageing_time));
1356 }
1357
1358 static void tun_flow_uninit(struct tun_struct *tun)
1359 {
1360         del_timer_sync(&tun->flow_gc_timer);
1361         tun_flow_flush(tun);
1362 }
1363
1364 #define MIN_MTU 68
1365 #define MAX_MTU 65535
1366
1367 /* Initialize net device. */
1368 static void tun_net_init(struct net_device *dev)
1369 {
1370         struct tun_struct *tun = netdev_priv(dev);
1371
1372         switch (tun->flags & TUN_TYPE_MASK) {
1373         case IFF_TUN:
1374                 dev->netdev_ops = &tun_netdev_ops;
1375
1376                 /* Point-to-Point TUN Device */
1377                 dev->hard_header_len = 0;
1378                 dev->addr_len = 0;
1379                 dev->mtu = 1500;
1380
1381                 /* Zero header length */
1382                 dev->type = ARPHRD_NONE;
1383                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1384                 break;
1385
1386         case IFF_TAP:
1387                 dev->netdev_ops = &tap_netdev_ops;
1388                 /* Ethernet TAP Device */
1389                 ether_setup(dev);
1390                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1391                 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1392
1393                 eth_hw_addr_random(dev);
1394
1395                 break;
1396         }
1397
1398         dev->min_mtu = MIN_MTU;
1399         dev->max_mtu = MAX_MTU - dev->hard_header_len;
1400 }
1401
1402 static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1403 {
1404         struct sock *sk = tfile->socket.sk;
1405
1406         return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1407 }
1408
1409 /* Character device part */
1410
1411 /* Poll */
1412 static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1413 {
1414         struct tun_file *tfile = file->private_data;
1415         struct tun_struct *tun = tun_get(tfile);
1416         struct sock *sk;
1417         __poll_t mask = 0;
1418
1419         if (!tun)
1420                 return EPOLLERR;
1421
1422         sk = tfile->socket.sk;
1423
1424         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1425
1426         poll_wait(file, sk_sleep(sk), wait);
1427
1428         if (!ptr_ring_empty(&tfile->tx_ring))
1429                 mask |= EPOLLIN | EPOLLRDNORM;
1430
1431         /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1432          * guarantee EPOLLOUT to be raised by either here or
1433          * tun_sock_write_space(). Then process could get notification
1434          * after it writes to a down device and meets -EIO.
1435          */
1436         if (tun_sock_writeable(tun, tfile) ||
1437             (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1438              tun_sock_writeable(tun, tfile)))
1439                 mask |= EPOLLOUT | EPOLLWRNORM;
1440
1441         if (tun->dev->reg_state != NETREG_REGISTERED)
1442                 mask = EPOLLERR;
1443
1444         tun_put(tun);
1445         return mask;
1446 }
1447
1448 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1449                                             size_t len,
1450                                             const struct iov_iter *it)
1451 {
1452         struct sk_buff *skb;
1453         size_t linear;
1454         int err;
1455         int i;
1456
1457         if (it->nr_segs > MAX_SKB_FRAGS + 1)
1458                 return ERR_PTR(-ENOMEM);
1459
1460         local_bh_disable();
1461         skb = napi_get_frags(&tfile->napi);
1462         local_bh_enable();
1463         if (!skb)
1464                 return ERR_PTR(-ENOMEM);
1465
1466         linear = iov_iter_single_seg_count(it);
1467         err = __skb_grow(skb, linear);
1468         if (err)
1469                 goto free;
1470
1471         skb->len = len;
1472         skb->data_len = len - linear;
1473         skb->truesize += skb->data_len;
1474
1475         for (i = 1; i < it->nr_segs; i++) {
1476                 struct page_frag *pfrag = &current->task_frag;
1477                 size_t fragsz = it->iov[i].iov_len;
1478
1479                 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1480                         err = -EINVAL;
1481                         goto free;
1482                 }
1483
1484                 if (!skb_page_frag_refill(fragsz, pfrag, GFP_KERNEL)) {
1485                         err = -ENOMEM;
1486                         goto free;
1487                 }
1488
1489                 skb_fill_page_desc(skb, i - 1, pfrag->page,
1490                                    pfrag->offset, fragsz);
1491                 page_ref_inc(pfrag->page);
1492                 pfrag->offset += fragsz;
1493         }
1494
1495         return skb;
1496 free:
1497         /* frees skb and all frags allocated with napi_alloc_frag() */
1498         napi_free_frags(&tfile->napi);
1499         return ERR_PTR(err);
1500 }
1501
1502 /* prepad is the amount to reserve at front.  len is length after that.
1503  * linear is a hint as to how much to copy (usually headers). */
1504 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1505                                      size_t prepad, size_t len,
1506                                      size_t linear, int noblock)
1507 {
1508         struct sock *sk = tfile->socket.sk;
1509         struct sk_buff *skb;
1510         int err;
1511
1512         /* Under a page?  Don't bother with paged skb. */
1513         if (prepad + len < PAGE_SIZE || !linear)
1514                 linear = len;
1515
1516         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1517                                    &err, 0);
1518         if (!skb)
1519                 return ERR_PTR(err);
1520
1521         skb_reserve(skb, prepad);
1522         skb_put(skb, linear);
1523         skb->data_len = len - linear;
1524         skb->len += len - linear;
1525
1526         return skb;
1527 }
1528
1529 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1530                            struct sk_buff *skb, int more)
1531 {
1532         struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1533         struct sk_buff_head process_queue;
1534         u32 rx_batched = tun->rx_batched;
1535         bool rcv = false;
1536
1537         if (!rx_batched || (!more && skb_queue_empty(queue))) {
1538                 local_bh_disable();
1539                 netif_receive_skb(skb);
1540                 local_bh_enable();
1541                 return;
1542         }
1543
1544         spin_lock(&queue->lock);
1545         if (!more || skb_queue_len(queue) == rx_batched) {
1546                 __skb_queue_head_init(&process_queue);
1547                 skb_queue_splice_tail_init(queue, &process_queue);
1548                 rcv = true;
1549         } else {
1550                 __skb_queue_tail(queue, skb);
1551         }
1552         spin_unlock(&queue->lock);
1553
1554         if (rcv) {
1555                 struct sk_buff *nskb;
1556
1557                 local_bh_disable();
1558                 while ((nskb = __skb_dequeue(&process_queue)))
1559                         netif_receive_skb(nskb);
1560                 netif_receive_skb(skb);
1561                 local_bh_enable();
1562         }
1563 }
1564
1565 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1566                               int len, int noblock, bool zerocopy)
1567 {
1568         if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1569                 return false;
1570
1571         if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1572                 return false;
1573
1574         if (!noblock)
1575                 return false;
1576
1577         if (zerocopy)
1578                 return false;
1579
1580         if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1581             SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1582                 return false;
1583
1584         return true;
1585 }
1586
1587 static struct sk_buff *__tun_build_skb(struct page_frag *alloc_frag, char *buf,
1588                                        int buflen, int len, int pad)
1589 {
1590         struct sk_buff *skb = build_skb(buf, buflen);
1591
1592         if (!skb)
1593                 return ERR_PTR(-ENOMEM);
1594
1595         skb_reserve(skb, pad);
1596         skb_put(skb, len);
1597
1598         get_page(alloc_frag->page);
1599         alloc_frag->offset += buflen;
1600
1601         return skb;
1602 }
1603
1604 static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1605                        struct xdp_buff *xdp, u32 act)
1606 {
1607         int err;
1608
1609         switch (act) {
1610         case XDP_REDIRECT:
1611                 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1612                 if (err)
1613                         return err;
1614                 break;
1615         case XDP_TX:
1616                 err = tun_xdp_tx(tun->dev, xdp);
1617                 if (err < 0)
1618                         return err;
1619                 break;
1620         case XDP_PASS:
1621                 break;
1622         default:
1623                 bpf_warn_invalid_xdp_action(act);
1624                 /* fall through */
1625         case XDP_ABORTED:
1626                 trace_xdp_exception(tun->dev, xdp_prog, act);
1627                 /* fall through */
1628         case XDP_DROP:
1629                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1630                 break;
1631         }
1632
1633         return act;
1634 }
1635
1636 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1637                                      struct tun_file *tfile,
1638                                      struct iov_iter *from,
1639                                      struct virtio_net_hdr *hdr,
1640                                      int len, int *skb_xdp)
1641 {
1642         struct page_frag *alloc_frag = &current->task_frag;
1643         struct bpf_prog *xdp_prog;
1644         int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1645         char *buf;
1646         size_t copied;
1647         int pad = TUN_RX_PAD;
1648         int err = 0;
1649
1650         rcu_read_lock();
1651         xdp_prog = rcu_dereference(tun->xdp_prog);
1652         if (xdp_prog)
1653                 pad += XDP_PACKET_HEADROOM;
1654         buflen += SKB_DATA_ALIGN(len + pad);
1655         rcu_read_unlock();
1656
1657         alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1658         if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1659                 return ERR_PTR(-ENOMEM);
1660
1661         buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1662         copied = copy_page_from_iter(alloc_frag->page,
1663                                      alloc_frag->offset + pad,
1664                                      len, from);
1665         if (copied != len)
1666                 return ERR_PTR(-EFAULT);
1667
1668         /* There's a small window that XDP may be set after the check
1669          * of xdp_prog above, this should be rare and for simplicity
1670          * we do XDP on skb in case the headroom is not enough.
1671          */
1672         if (hdr->gso_type || !xdp_prog) {
1673                 *skb_xdp = 1;
1674                 return __tun_build_skb(alloc_frag, buf, buflen, len, pad);
1675         }
1676
1677         *skb_xdp = 0;
1678
1679         local_bh_disable();
1680         rcu_read_lock();
1681         xdp_prog = rcu_dereference(tun->xdp_prog);
1682         if (xdp_prog) {
1683                 struct xdp_buff xdp;
1684                 u32 act;
1685
1686                 xdp.data_hard_start = buf;
1687                 xdp.data = buf + pad;
1688                 xdp_set_data_meta_invalid(&xdp);
1689                 xdp.data_end = xdp.data + len;
1690                 xdp.rxq = &tfile->xdp_rxq;
1691
1692                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1693                 if (act == XDP_REDIRECT || act == XDP_TX) {
1694                         get_page(alloc_frag->page);
1695                         alloc_frag->offset += buflen;
1696                 }
1697                 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1698                 if (err < 0)
1699                         goto err_xdp;
1700                 if (err == XDP_REDIRECT)
1701                         xdp_do_flush_map();
1702                 if (err != XDP_PASS)
1703                         goto out;
1704
1705                 pad = xdp.data - xdp.data_hard_start;
1706                 len = xdp.data_end - xdp.data;
1707         }
1708         rcu_read_unlock();
1709         local_bh_enable();
1710
1711         return __tun_build_skb(alloc_frag, buf, buflen, len, pad);
1712
1713 err_xdp:
1714         put_page(alloc_frag->page);
1715 out:
1716         rcu_read_unlock();
1717         local_bh_enable();
1718         return NULL;
1719 }
1720
1721 /* Get packet from user space buffer */
1722 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1723                             void *msg_control, struct iov_iter *from,
1724                             int noblock, bool more)
1725 {
1726         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1727         struct sk_buff *skb;
1728         size_t total_len = iov_iter_count(from);
1729         size_t len = total_len, align = tun->align, linear;
1730         struct virtio_net_hdr gso = { 0 };
1731         struct tun_pcpu_stats *stats;
1732         int good_linear;
1733         int copylen;
1734         bool zerocopy = false;
1735         int err;
1736         u32 rxhash = 0;
1737         int skb_xdp = 1;
1738         bool frags = tun_napi_frags_enabled(tfile);
1739
1740         if (!(tun->dev->flags & IFF_UP))
1741                 return -EIO;
1742
1743         if (!(tun->flags & IFF_NO_PI)) {
1744                 if (len < sizeof(pi))
1745                         return -EINVAL;
1746                 len -= sizeof(pi);
1747
1748                 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1749                         return -EFAULT;
1750         }
1751
1752         if (tun->flags & IFF_VNET_HDR) {
1753                 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1754
1755                 if (len < vnet_hdr_sz)
1756                         return -EINVAL;
1757                 len -= vnet_hdr_sz;
1758
1759                 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1760                         return -EFAULT;
1761
1762                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1763                     tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1764                         gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1765
1766                 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1767                         return -EINVAL;
1768                 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1769         }
1770
1771         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1772                 align += NET_IP_ALIGN;
1773                 if (unlikely(len < ETH_HLEN ||
1774                              (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1775                         return -EINVAL;
1776         }
1777
1778         good_linear = SKB_MAX_HEAD(align);
1779
1780         if (msg_control) {
1781                 struct iov_iter i = *from;
1782
1783                 /* There are 256 bytes to be copied in skb, so there is
1784                  * enough room for skb expand head in case it is used.
1785                  * The rest of the buffer is mapped from userspace.
1786                  */
1787                 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1788                 if (copylen > good_linear)
1789                         copylen = good_linear;
1790                 linear = copylen;
1791                 iov_iter_advance(&i, copylen);
1792                 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1793                         zerocopy = true;
1794         }
1795
1796         if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1797                 /* For the packet that is not easy to be processed
1798                  * (e.g gso or jumbo packet), we will do it at after
1799                  * skb was created with generic XDP routine.
1800                  */
1801                 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1802                 if (IS_ERR(skb)) {
1803                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1804                         return PTR_ERR(skb);
1805                 }
1806                 if (!skb)
1807                         return total_len;
1808         } else {
1809                 if (!zerocopy) {
1810                         copylen = len;
1811                         if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1812                                 linear = good_linear;
1813                         else
1814                                 linear = tun16_to_cpu(tun, gso.hdr_len);
1815                 }
1816
1817                 if (frags) {
1818                         mutex_lock(&tfile->napi_mutex);
1819                         skb = tun_napi_alloc_frags(tfile, copylen, from);
1820                         /* tun_napi_alloc_frags() enforces a layout for the skb.
1821                          * If zerocopy is enabled, then this layout will be
1822                          * overwritten by zerocopy_sg_from_iter().
1823                          */
1824                         zerocopy = false;
1825                 } else {
1826                         skb = tun_alloc_skb(tfile, align, copylen, linear,
1827                                             noblock);
1828                 }
1829
1830                 if (IS_ERR(skb)) {
1831                         if (PTR_ERR(skb) != -EAGAIN)
1832                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1833                         if (frags)
1834                                 mutex_unlock(&tfile->napi_mutex);
1835                         return PTR_ERR(skb);
1836                 }
1837
1838                 if (zerocopy)
1839                         err = zerocopy_sg_from_iter(skb, from);
1840                 else
1841                         err = skb_copy_datagram_from_iter(skb, 0, from, len);
1842
1843                 if (err) {
1844                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1845                         kfree_skb(skb);
1846                         if (frags) {
1847                                 tfile->napi.skb = NULL;
1848                                 mutex_unlock(&tfile->napi_mutex);
1849                         }
1850
1851                         return -EFAULT;
1852                 }
1853         }
1854
1855         if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1856                 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1857                 kfree_skb(skb);
1858                 if (frags) {
1859                         tfile->napi.skb = NULL;
1860                         mutex_unlock(&tfile->napi_mutex);
1861                 }
1862
1863                 return -EINVAL;
1864         }
1865
1866         switch (tun->flags & TUN_TYPE_MASK) {
1867         case IFF_TUN:
1868                 if (tun->flags & IFF_NO_PI) {
1869                         u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1870
1871                         switch (ip_version) {
1872                         case 4:
1873                                 pi.proto = htons(ETH_P_IP);
1874                                 break;
1875                         case 6:
1876                                 pi.proto = htons(ETH_P_IPV6);
1877                                 break;
1878                         default:
1879                                 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1880                                 kfree_skb(skb);
1881                                 return -EINVAL;
1882                         }
1883                 }
1884
1885                 skb_reset_mac_header(skb);
1886                 skb->protocol = pi.proto;
1887                 skb->dev = tun->dev;
1888                 break;
1889         case IFF_TAP:
1890                 if (!frags)
1891                         skb->protocol = eth_type_trans(skb, tun->dev);
1892                 break;
1893         }
1894
1895         /* copy skb_ubuf_info for callback when skb has no error */
1896         if (zerocopy) {
1897                 skb_shinfo(skb)->destructor_arg = msg_control;
1898                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1899                 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1900         } else if (msg_control) {
1901                 struct ubuf_info *uarg = msg_control;
1902                 uarg->callback(uarg, false);
1903         }
1904
1905         skb_reset_network_header(skb);
1906         skb_probe_transport_header(skb, 0);
1907
1908         if (skb_xdp) {
1909                 struct bpf_prog *xdp_prog;
1910                 int ret;
1911
1912                 local_bh_disable();
1913                 rcu_read_lock();
1914                 xdp_prog = rcu_dereference(tun->xdp_prog);
1915                 if (xdp_prog) {
1916                         ret = do_xdp_generic(xdp_prog, skb);
1917                         if (ret != XDP_PASS) {
1918                                 rcu_read_unlock();
1919                                 local_bh_enable();
1920                                 return total_len;
1921                         }
1922                 }
1923                 rcu_read_unlock();
1924                 local_bh_enable();
1925         }
1926
1927         /* Compute the costly rx hash only if needed for flow updates.
1928          * We may get a very small possibility of OOO during switching, not
1929          * worth to optimize.
1930          */
1931         if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1932             !tfile->detached)
1933                 rxhash = __skb_get_hash_symmetric(skb);
1934
1935         if (frags) {
1936                 /* Exercise flow dissector code path. */
1937                 u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb));
1938
1939                 if (unlikely(headlen > skb_headlen(skb))) {
1940                         this_cpu_inc(tun->pcpu_stats->rx_dropped);
1941                         napi_free_frags(&tfile->napi);
1942                         mutex_unlock(&tfile->napi_mutex);
1943                         WARN_ON(1);
1944                         return -ENOMEM;
1945                 }
1946
1947                 local_bh_disable();
1948                 napi_gro_frags(&tfile->napi);
1949                 local_bh_enable();
1950                 mutex_unlock(&tfile->napi_mutex);
1951         } else if (tfile->napi_enabled) {
1952                 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1953                 int queue_len;
1954
1955                 spin_lock_bh(&queue->lock);
1956                 __skb_queue_tail(queue, skb);
1957                 queue_len = skb_queue_len(queue);
1958                 spin_unlock(&queue->lock);
1959
1960                 if (!more || queue_len > NAPI_POLL_WEIGHT)
1961                         napi_schedule(&tfile->napi);
1962
1963                 local_bh_enable();
1964         } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1965                 tun_rx_batched(tun, tfile, skb, more);
1966         } else {
1967                 netif_rx_ni(skb);
1968         }
1969
1970         stats = get_cpu_ptr(tun->pcpu_stats);
1971         u64_stats_update_begin(&stats->syncp);
1972         stats->rx_packets++;
1973         stats->rx_bytes += len;
1974         u64_stats_update_end(&stats->syncp);
1975         put_cpu_ptr(stats);
1976
1977         if (rxhash)
1978                 tun_flow_update(tun, rxhash, tfile);
1979
1980         return total_len;
1981 }
1982
1983 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1984 {
1985         struct file *file = iocb->ki_filp;
1986         struct tun_file *tfile = file->private_data;
1987         struct tun_struct *tun = tun_get(tfile);
1988         ssize_t result;
1989
1990         if (!tun)
1991                 return -EBADFD;
1992
1993         result = tun_get_user(tun, tfile, NULL, from,
1994                               file->f_flags & O_NONBLOCK, false);
1995
1996         tun_put(tun);
1997         return result;
1998 }
1999
2000 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2001                                 struct tun_file *tfile,
2002                                 struct xdp_frame *xdp_frame,
2003                                 struct iov_iter *iter)
2004 {
2005         int vnet_hdr_sz = 0;
2006         size_t size = xdp_frame->len;
2007         struct tun_pcpu_stats *stats;
2008         size_t ret;
2009
2010         if (tun->flags & IFF_VNET_HDR) {
2011                 struct virtio_net_hdr gso = { 0 };
2012
2013                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2014                 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2015                         return -EINVAL;
2016                 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2017                              sizeof(gso)))
2018                         return -EFAULT;
2019                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2020         }
2021
2022         ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2023
2024         stats = get_cpu_ptr(tun->pcpu_stats);
2025         u64_stats_update_begin(&stats->syncp);
2026         stats->tx_packets++;
2027         stats->tx_bytes += ret;
2028         u64_stats_update_end(&stats->syncp);
2029         put_cpu_ptr(tun->pcpu_stats);
2030
2031         return ret;
2032 }
2033
2034 /* Put packet to the user space buffer */
2035 static ssize_t tun_put_user(struct tun_struct *tun,
2036                             struct tun_file *tfile,
2037                             struct sk_buff *skb,
2038                             struct iov_iter *iter)
2039 {
2040         struct tun_pi pi = { 0, skb->protocol };
2041         struct tun_pcpu_stats *stats;
2042         ssize_t total;
2043         int vlan_offset = 0;
2044         int vlan_hlen = 0;
2045         int vnet_hdr_sz = 0;
2046
2047         if (skb_vlan_tag_present(skb))
2048                 vlan_hlen = VLAN_HLEN;
2049
2050         if (tun->flags & IFF_VNET_HDR)
2051                 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2052
2053         total = skb->len + vlan_hlen + vnet_hdr_sz;
2054
2055         if (!(tun->flags & IFF_NO_PI)) {
2056                 if (iov_iter_count(iter) < sizeof(pi))
2057                         return -EINVAL;
2058
2059                 total += sizeof(pi);
2060                 if (iov_iter_count(iter) < total) {
2061                         /* Packet will be striped */
2062                         pi.flags |= TUN_PKT_STRIP;
2063                 }
2064
2065                 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2066                         return -EFAULT;
2067         }
2068
2069         if (vnet_hdr_sz) {
2070                 struct virtio_net_hdr gso;
2071
2072                 if (iov_iter_count(iter) < vnet_hdr_sz)
2073                         return -EINVAL;
2074
2075                 if (virtio_net_hdr_from_skb(skb, &gso,
2076                                             tun_is_little_endian(tun), true,
2077                                             vlan_hlen)) {
2078                         struct skb_shared_info *sinfo = skb_shinfo(skb);
2079                         pr_err("unexpected GSO type: "
2080                                "0x%x, gso_size %d, hdr_len %d\n",
2081                                sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2082                                tun16_to_cpu(tun, gso.hdr_len));
2083                         print_hex_dump(KERN_ERR, "tun: ",
2084                                        DUMP_PREFIX_NONE,
2085                                        16, 1, skb->head,
2086                                        min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2087                         WARN_ON_ONCE(1);
2088                         return -EINVAL;
2089                 }
2090
2091                 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2092                         return -EFAULT;
2093
2094                 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2095         }
2096
2097         if (vlan_hlen) {
2098                 int ret;
2099                 struct veth veth;
2100
2101                 veth.h_vlan_proto = skb->vlan_proto;
2102                 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2103
2104                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2105
2106                 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2107                 if (ret || !iov_iter_count(iter))
2108                         goto done;
2109
2110                 ret = copy_to_iter(&veth, sizeof(veth), iter);
2111                 if (ret != sizeof(veth) || !iov_iter_count(iter))
2112                         goto done;
2113         }
2114
2115         skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2116
2117 done:
2118         /* caller is in process context, */
2119         stats = get_cpu_ptr(tun->pcpu_stats);
2120         u64_stats_update_begin(&stats->syncp);
2121         stats->tx_packets++;
2122         stats->tx_bytes += skb->len + vlan_hlen;
2123         u64_stats_update_end(&stats->syncp);
2124         put_cpu_ptr(tun->pcpu_stats);
2125
2126         return total;
2127 }
2128
2129 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2130 {
2131         DECLARE_WAITQUEUE(wait, current);
2132         void *ptr = NULL;
2133         int error = 0;
2134
2135         ptr = ptr_ring_consume(&tfile->tx_ring);
2136         if (ptr)
2137                 goto out;
2138         if (noblock) {
2139                 error = -EAGAIN;
2140                 goto out;
2141         }
2142
2143         add_wait_queue(&tfile->wq.wait, &wait);
2144         current->state = TASK_INTERRUPTIBLE;
2145
2146         while (1) {
2147                 ptr = ptr_ring_consume(&tfile->tx_ring);
2148                 if (ptr)
2149                         break;
2150                 if (signal_pending(current)) {
2151                         error = -ERESTARTSYS;
2152                         break;
2153                 }
2154                 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2155                         error = -EFAULT;
2156                         break;
2157                 }
2158
2159                 schedule();
2160         }
2161
2162         current->state = TASK_RUNNING;
2163         remove_wait_queue(&tfile->wq.wait, &wait);
2164
2165 out:
2166         *err = error;
2167         return ptr;
2168 }
2169
2170 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2171                            struct iov_iter *to,
2172                            int noblock, void *ptr)
2173 {
2174         ssize_t ret;
2175         int err;
2176
2177         tun_debug(KERN_INFO, tun, "tun_do_read\n");
2178
2179         if (!iov_iter_count(to)) {
2180                 tun_ptr_free(ptr);
2181                 return 0;
2182         }
2183
2184         if (!ptr) {
2185                 /* Read frames from ring */
2186                 ptr = tun_ring_recv(tfile, noblock, &err);
2187                 if (!ptr)
2188                         return err;
2189         }
2190
2191         if (tun_is_xdp_frame(ptr)) {
2192                 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2193
2194                 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2195                 xdp_return_frame(xdpf);
2196         } else {
2197                 struct sk_buff *skb = ptr;
2198
2199                 ret = tun_put_user(tun, tfile, skb, to);
2200                 if (unlikely(ret < 0))
2201                         kfree_skb(skb);
2202                 else
2203                         consume_skb(skb);
2204         }
2205
2206         return ret;
2207 }
2208
2209 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2210 {
2211         struct file *file = iocb->ki_filp;
2212         struct tun_file *tfile = file->private_data;
2213         struct tun_struct *tun = tun_get(tfile);
2214         ssize_t len = iov_iter_count(to), ret;
2215
2216         if (!tun)
2217                 return -EBADFD;
2218         ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2219         ret = min_t(ssize_t, ret, len);
2220         if (ret > 0)
2221                 iocb->ki_pos = ret;
2222         tun_put(tun);
2223         return ret;
2224 }
2225
2226 static void tun_prog_free(struct rcu_head *rcu)
2227 {
2228         struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2229
2230         bpf_prog_destroy(prog->prog);
2231         kfree(prog);
2232 }
2233
2234 static int __tun_set_ebpf(struct tun_struct *tun,
2235                           struct tun_prog __rcu **prog_p,
2236                           struct bpf_prog *prog)
2237 {
2238         struct tun_prog *old, *new = NULL;
2239
2240         if (prog) {
2241                 new = kmalloc(sizeof(*new), GFP_KERNEL);
2242                 if (!new)
2243                         return -ENOMEM;
2244                 new->prog = prog;
2245         }
2246
2247         spin_lock_bh(&tun->lock);
2248         old = rcu_dereference_protected(*prog_p,
2249                                         lockdep_is_held(&tun->lock));
2250         rcu_assign_pointer(*prog_p, new);
2251         spin_unlock_bh(&tun->lock);
2252
2253         if (old)
2254                 call_rcu(&old->rcu, tun_prog_free);
2255
2256         return 0;
2257 }
2258
2259 static void tun_free_netdev(struct net_device *dev)
2260 {
2261         struct tun_struct *tun = netdev_priv(dev);
2262
2263         BUG_ON(!(list_empty(&tun->disabled)));
2264         free_percpu(tun->pcpu_stats);
2265         tun_flow_uninit(tun);
2266         security_tun_dev_free_security(tun->security);
2267         __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2268         __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2269 }
2270
2271 static void tun_setup(struct net_device *dev)
2272 {
2273         struct tun_struct *tun = netdev_priv(dev);
2274
2275         tun->owner = INVALID_UID;
2276         tun->group = INVALID_GID;
2277         tun_default_link_ksettings(dev, &tun->link_ksettings);
2278
2279         dev->ethtool_ops = &tun_ethtool_ops;
2280         dev->needs_free_netdev = true;
2281         dev->priv_destructor = tun_free_netdev;
2282         /* We prefer our own queue length */
2283         dev->tx_queue_len = TUN_READQ_SIZE;
2284 }
2285
2286 /* Trivial set of netlink ops to allow deleting tun or tap
2287  * device with netlink.
2288  */
2289 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2290                         struct netlink_ext_ack *extack)
2291 {
2292         if (!data)
2293                 return 0;
2294         return -EINVAL;
2295 }
2296
2297 static size_t tun_get_size(const struct net_device *dev)
2298 {
2299         BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2300         BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2301
2302         return nla_total_size(sizeof(uid_t)) + /* OWNER */
2303                nla_total_size(sizeof(gid_t)) + /* GROUP */
2304                nla_total_size(sizeof(u8)) + /* TYPE */
2305                nla_total_size(sizeof(u8)) + /* PI */
2306                nla_total_size(sizeof(u8)) + /* VNET_HDR */
2307                nla_total_size(sizeof(u8)) + /* PERSIST */
2308                nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2309                nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2310                nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2311                0;
2312 }
2313
2314 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2315 {
2316         struct tun_struct *tun = netdev_priv(dev);
2317
2318         if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2319                 goto nla_put_failure;
2320         if (uid_valid(tun->owner) &&
2321             nla_put_u32(skb, IFLA_TUN_OWNER,
2322                         from_kuid_munged(current_user_ns(), tun->owner)))
2323                 goto nla_put_failure;
2324         if (gid_valid(tun->group) &&
2325             nla_put_u32(skb, IFLA_TUN_GROUP,
2326                         from_kgid_munged(current_user_ns(), tun->group)))
2327                 goto nla_put_failure;
2328         if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2329                 goto nla_put_failure;
2330         if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2331                 goto nla_put_failure;
2332         if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2333                 goto nla_put_failure;
2334         if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2335                        !!(tun->flags & IFF_MULTI_QUEUE)))
2336                 goto nla_put_failure;
2337         if (tun->flags & IFF_MULTI_QUEUE) {
2338                 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2339                         goto nla_put_failure;
2340                 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2341                                 tun->numdisabled))
2342                         goto nla_put_failure;
2343         }
2344
2345         return 0;
2346
2347 nla_put_failure:
2348         return -EMSGSIZE;
2349 }
2350
2351 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2352         .kind           = DRV_NAME,
2353         .priv_size      = sizeof(struct tun_struct),
2354         .setup          = tun_setup,
2355         .validate       = tun_validate,
2356         .get_size       = tun_get_size,
2357         .fill_info      = tun_fill_info,
2358 };
2359
2360 static void tun_sock_write_space(struct sock *sk)
2361 {
2362         struct tun_file *tfile;
2363         wait_queue_head_t *wqueue;
2364
2365         if (!sock_writeable(sk))
2366                 return;
2367
2368         if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2369                 return;
2370
2371         wqueue = sk_sleep(sk);
2372         if (wqueue && waitqueue_active(wqueue))
2373                 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2374                                                 EPOLLWRNORM | EPOLLWRBAND);
2375
2376         tfile = container_of(sk, struct tun_file, sk);
2377         kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2378 }
2379
2380 static int tun_xdp_one(struct tun_struct *tun,
2381                        struct tun_file *tfile,
2382                        struct xdp_buff *xdp, int *flush)
2383 {
2384         struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2385         struct virtio_net_hdr *gso = &hdr->gso;
2386         struct tun_pcpu_stats *stats;
2387         struct bpf_prog *xdp_prog;
2388         struct sk_buff *skb = NULL;
2389         u32 rxhash = 0, act;
2390         int buflen = hdr->buflen;
2391         int err = 0;
2392         bool skb_xdp = false;
2393
2394         xdp_prog = rcu_dereference(tun->xdp_prog);
2395         if (xdp_prog) {
2396                 if (gso->gso_type) {
2397                         skb_xdp = true;
2398                         goto build;
2399                 }
2400                 xdp_set_data_meta_invalid(xdp);
2401                 xdp->rxq = &tfile->xdp_rxq;
2402
2403                 act = bpf_prog_run_xdp(xdp_prog, xdp);
2404                 err = tun_xdp_act(tun, xdp_prog, xdp, act);
2405                 if (err < 0) {
2406                         put_page(virt_to_head_page(xdp->data));
2407                         return err;
2408                 }
2409
2410                 switch (err) {
2411                 case XDP_REDIRECT:
2412                         *flush = true;
2413                         /* fall through */
2414                 case XDP_TX:
2415                         return 0;
2416                 case XDP_PASS:
2417                         break;
2418                 default:
2419                         put_page(virt_to_head_page(xdp->data));
2420                         return 0;
2421                 }
2422         }
2423
2424 build:
2425         skb = build_skb(xdp->data_hard_start, buflen);
2426         if (!skb) {
2427                 err = -ENOMEM;
2428                 goto out;
2429         }
2430
2431         skb_reserve(skb, xdp->data - xdp->data_hard_start);
2432         skb_put(skb, xdp->data_end - xdp->data);
2433
2434         if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2435                 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
2436                 kfree_skb(skb);
2437                 err = -EINVAL;
2438                 goto out;
2439         }
2440
2441         skb->protocol = eth_type_trans(skb, tun->dev);
2442         skb_reset_network_header(skb);
2443         skb_probe_transport_header(skb, 0);
2444
2445         if (skb_xdp) {
2446                 err = do_xdp_generic(xdp_prog, skb);
2447                 if (err != XDP_PASS)
2448                         goto out;
2449         }
2450
2451         if (!rcu_dereference(tun->steering_prog))
2452                 rxhash = __skb_get_hash_symmetric(skb);
2453
2454         netif_receive_skb(skb);
2455
2456         stats = get_cpu_ptr(tun->pcpu_stats);
2457         u64_stats_update_begin(&stats->syncp);
2458         stats->rx_packets++;
2459         stats->rx_bytes += skb->len;
2460         u64_stats_update_end(&stats->syncp);
2461         put_cpu_ptr(stats);
2462
2463         if (rxhash)
2464                 tun_flow_update(tun, rxhash, tfile);
2465
2466 out:
2467         return err;
2468 }
2469
2470 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2471 {
2472         int ret, i;
2473         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2474         struct tun_struct *tun = tun_get(tfile);
2475         struct tun_msg_ctl *ctl = m->msg_control;
2476         struct xdp_buff *xdp;
2477
2478         if (!tun)
2479                 return -EBADFD;
2480
2481         if (ctl && (ctl->type == TUN_MSG_PTR)) {
2482                 int n = ctl->num;
2483                 int flush = 0;
2484
2485                 local_bh_disable();
2486                 rcu_read_lock();
2487
2488                 for (i = 0; i < n; i++) {
2489                         xdp = &((struct xdp_buff *)ctl->ptr)[i];
2490                         tun_xdp_one(tun, tfile, xdp, &flush);
2491                 }
2492
2493                 if (flush)
2494                         xdp_do_flush_map();
2495
2496                 rcu_read_unlock();
2497                 local_bh_enable();
2498
2499                 ret = total_len;
2500                 goto out;
2501         }
2502
2503         ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2504                            m->msg_flags & MSG_DONTWAIT,
2505                            m->msg_flags & MSG_MORE);
2506 out:
2507         tun_put(tun);
2508         return ret;
2509 }
2510
2511 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2512                        int flags)
2513 {
2514         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2515         struct tun_struct *tun = tun_get(tfile);
2516         void *ptr = m->msg_control;
2517         int ret;
2518
2519         if (!tun) {
2520                 ret = -EBADFD;
2521                 goto out_free;
2522         }
2523
2524         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2525                 ret = -EINVAL;
2526                 goto out_put_tun;
2527         }
2528         if (flags & MSG_ERRQUEUE) {
2529                 ret = sock_recv_errqueue(sock->sk, m, total_len,
2530                                          SOL_PACKET, TUN_TX_TIMESTAMP);
2531                 goto out;
2532         }
2533         ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2534         if (ret > (ssize_t)total_len) {
2535                 m->msg_flags |= MSG_TRUNC;
2536                 ret = flags & MSG_TRUNC ? ret : total_len;
2537         }
2538 out:
2539         tun_put(tun);
2540         return ret;
2541
2542 out_put_tun:
2543         tun_put(tun);
2544 out_free:
2545         tun_ptr_free(ptr);
2546         return ret;
2547 }
2548
2549 static int tun_ptr_peek_len(void *ptr)
2550 {
2551         if (likely(ptr)) {
2552                 if (tun_is_xdp_frame(ptr)) {
2553                         struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2554
2555                         return xdpf->len;
2556                 }
2557                 return __skb_array_len_with_tag(ptr);
2558         } else {
2559                 return 0;
2560         }
2561 }
2562
2563 static int tun_peek_len(struct socket *sock)
2564 {
2565         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2566         struct tun_struct *tun;
2567         int ret = 0;
2568
2569         tun = tun_get(tfile);
2570         if (!tun)
2571                 return 0;
2572
2573         ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2574         tun_put(tun);
2575
2576         return ret;
2577 }
2578
2579 /* Ops structure to mimic raw sockets with tun */
2580 static const struct proto_ops tun_socket_ops = {
2581         .peek_len = tun_peek_len,
2582         .sendmsg = tun_sendmsg,
2583         .recvmsg = tun_recvmsg,
2584 };
2585
2586 static struct proto tun_proto = {
2587         .name           = "tun",
2588         .owner          = THIS_MODULE,
2589         .obj_size       = sizeof(struct tun_file),
2590 };
2591
2592 static int tun_flags(struct tun_struct *tun)
2593 {
2594         return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2595 }
2596
2597 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2598                               char *buf)
2599 {
2600         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2601         return sprintf(buf, "0x%x\n", tun_flags(tun));
2602 }
2603
2604 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2605                               char *buf)
2606 {
2607         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2608         return uid_valid(tun->owner)?
2609                 sprintf(buf, "%u\n",
2610                         from_kuid_munged(current_user_ns(), tun->owner)):
2611                 sprintf(buf, "-1\n");
2612 }
2613
2614 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2615                               char *buf)
2616 {
2617         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2618         return gid_valid(tun->group) ?
2619                 sprintf(buf, "%u\n",
2620                         from_kgid_munged(current_user_ns(), tun->group)):
2621                 sprintf(buf, "-1\n");
2622 }
2623
2624 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2625 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2626 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2627
2628 static struct attribute *tun_dev_attrs[] = {
2629         &dev_attr_tun_flags.attr,
2630         &dev_attr_owner.attr,
2631         &dev_attr_group.attr,
2632         NULL
2633 };
2634
2635 static const struct attribute_group tun_attr_group = {
2636         .attrs = tun_dev_attrs
2637 };
2638
2639 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2640 {
2641         struct tun_struct *tun;
2642         struct tun_file *tfile = file->private_data;
2643         struct net_device *dev;
2644         int err;
2645
2646         if (tfile->detached)
2647                 return -EINVAL;
2648
2649         if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2650                 if (!capable(CAP_NET_ADMIN))
2651                         return -EPERM;
2652
2653                 if (!(ifr->ifr_flags & IFF_NAPI) ||
2654                     (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2655                         return -EINVAL;
2656         }
2657
2658         dev = __dev_get_by_name(net, ifr->ifr_name);
2659         if (dev) {
2660                 if (ifr->ifr_flags & IFF_TUN_EXCL)
2661                         return -EBUSY;
2662                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2663                         tun = netdev_priv(dev);
2664                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2665                         tun = netdev_priv(dev);
2666                 else
2667                         return -EINVAL;
2668
2669                 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2670                     !!(tun->flags & IFF_MULTI_QUEUE))
2671                         return -EINVAL;
2672
2673                 if (tun_not_capable(tun))
2674                         return -EPERM;
2675                 err = security_tun_dev_open(tun->security);
2676                 if (err < 0)
2677                         return err;
2678
2679                 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2680                                  ifr->ifr_flags & IFF_NAPI,
2681                                  ifr->ifr_flags & IFF_NAPI_FRAGS);
2682                 if (err < 0)
2683                         return err;
2684
2685                 if (tun->flags & IFF_MULTI_QUEUE &&
2686                     (tun->numqueues + tun->numdisabled > 1)) {
2687                         /* One or more queue has already been attached, no need
2688                          * to initialize the device again.
2689                          */
2690                         netdev_state_change(dev);
2691                         return 0;
2692                 }
2693
2694                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2695                               (ifr->ifr_flags & TUN_FEATURES);
2696
2697                 netdev_state_change(dev);
2698         } else {
2699                 char *name;
2700                 unsigned long flags = 0;
2701                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2702                              MAX_TAP_QUEUES : 1;
2703
2704                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2705                         return -EPERM;
2706                 err = security_tun_dev_create();
2707                 if (err < 0)
2708                         return err;
2709
2710                 /* Set dev type */
2711                 if (ifr->ifr_flags & IFF_TUN) {
2712                         /* TUN device */
2713                         flags |= IFF_TUN;
2714                         name = "tun%d";
2715                 } else if (ifr->ifr_flags & IFF_TAP) {
2716                         /* TAP device */
2717                         flags |= IFF_TAP;
2718                         name = "tap%d";
2719                 } else
2720                         return -EINVAL;
2721
2722                 if (*ifr->ifr_name)
2723                         name = ifr->ifr_name;
2724
2725                 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2726                                        NET_NAME_UNKNOWN, tun_setup, queues,
2727                                        queues);
2728
2729                 if (!dev)
2730                         return -ENOMEM;
2731                 err = dev_get_valid_name(net, dev, name);
2732                 if (err < 0)
2733                         goto err_free_dev;
2734
2735                 dev_net_set(dev, net);
2736                 dev->rtnl_link_ops = &tun_link_ops;
2737                 dev->ifindex = tfile->ifindex;
2738                 dev->sysfs_groups[0] = &tun_attr_group;
2739
2740                 tun = netdev_priv(dev);
2741                 tun->dev = dev;
2742                 tun->flags = flags;
2743                 tun->txflt.count = 0;
2744                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2745
2746                 tun->align = NET_SKB_PAD;
2747                 tun->filter_attached = false;
2748                 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2749                 tun->rx_batched = 0;
2750                 RCU_INIT_POINTER(tun->steering_prog, NULL);
2751
2752                 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2753                 if (!tun->pcpu_stats) {
2754                         err = -ENOMEM;
2755                         goto err_free_dev;
2756                 }
2757
2758                 spin_lock_init(&tun->lock);
2759
2760                 err = security_tun_dev_alloc_security(&tun->security);
2761                 if (err < 0)
2762                         goto err_free_stat;
2763
2764                 tun_net_init(dev);
2765                 tun_flow_init(tun);
2766
2767                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2768                                    TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2769                                    NETIF_F_HW_VLAN_STAG_TX;
2770                 dev->features = dev->hw_features | NETIF_F_LLTX;
2771                 dev->vlan_features = dev->features &
2772                                      ~(NETIF_F_HW_VLAN_CTAG_TX |
2773                                        NETIF_F_HW_VLAN_STAG_TX);
2774
2775                 tun->flags = (tun->flags & ~TUN_FEATURES) |
2776                               (ifr->ifr_flags & TUN_FEATURES);
2777
2778                 INIT_LIST_HEAD(&tun->disabled);
2779                 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI,
2780                                  ifr->ifr_flags & IFF_NAPI_FRAGS);
2781                 if (err < 0)
2782                         goto err_free_flow;
2783
2784                 err = register_netdevice(tun->dev);
2785                 if (err < 0)
2786                         goto err_detach;
2787         }
2788
2789         netif_carrier_on(tun->dev);
2790
2791         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2792
2793         /* Make sure persistent devices do not get stuck in
2794          * xoff state.
2795          */
2796         if (netif_running(tun->dev))
2797                 netif_tx_wake_all_queues(tun->dev);
2798
2799         strcpy(ifr->ifr_name, tun->dev->name);
2800         return 0;
2801
2802 err_detach:
2803         tun_detach_all(dev);
2804         /* register_netdevice() already called tun_free_netdev() */
2805         goto err_free_dev;
2806
2807 err_free_flow:
2808         tun_flow_uninit(tun);
2809         security_tun_dev_free_security(tun->security);
2810 err_free_stat:
2811         free_percpu(tun->pcpu_stats);
2812 err_free_dev:
2813         free_netdev(dev);
2814         return err;
2815 }
2816
2817 static void tun_get_iff(struct net *net, struct tun_struct *tun,
2818                        struct ifreq *ifr)
2819 {
2820         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2821
2822         strcpy(ifr->ifr_name, tun->dev->name);
2823
2824         ifr->ifr_flags = tun_flags(tun);
2825
2826 }
2827
2828 /* This is like a cut-down ethtool ops, except done via tun fd so no
2829  * privs required. */
2830 static int set_offload(struct tun_struct *tun, unsigned long arg)
2831 {
2832         netdev_features_t features = 0;
2833
2834         if (arg & TUN_F_CSUM) {
2835                 features |= NETIF_F_HW_CSUM;
2836                 arg &= ~TUN_F_CSUM;
2837
2838                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2839                         if (arg & TUN_F_TSO_ECN) {
2840                                 features |= NETIF_F_TSO_ECN;
2841                                 arg &= ~TUN_F_TSO_ECN;
2842                         }
2843                         if (arg & TUN_F_TSO4)
2844                                 features |= NETIF_F_TSO;
2845                         if (arg & TUN_F_TSO6)
2846                                 features |= NETIF_F_TSO6;
2847                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2848                 }
2849
2850                 arg &= ~TUN_F_UFO;
2851         }
2852
2853         /* This gives the user a way to test for new features in future by
2854          * trying to set them. */
2855         if (arg)
2856                 return -EINVAL;
2857
2858         tun->set_features = features;
2859         tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2860         tun->dev->wanted_features |= features;
2861         netdev_update_features(tun->dev);
2862
2863         return 0;
2864 }
2865
2866 static void tun_detach_filter(struct tun_struct *tun, int n)
2867 {
2868         int i;
2869         struct tun_file *tfile;
2870
2871         for (i = 0; i < n; i++) {
2872                 tfile = rtnl_dereference(tun->tfiles[i]);
2873                 lock_sock(tfile->socket.sk);
2874                 sk_detach_filter(tfile->socket.sk);
2875                 release_sock(tfile->socket.sk);
2876         }
2877
2878         tun->filter_attached = false;
2879 }
2880
2881 static int tun_attach_filter(struct tun_struct *tun)
2882 {
2883         int i, ret = 0;
2884         struct tun_file *tfile;
2885
2886         for (i = 0; i < tun->numqueues; i++) {
2887                 tfile = rtnl_dereference(tun->tfiles[i]);
2888                 lock_sock(tfile->socket.sk);
2889                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2890                 release_sock(tfile->socket.sk);
2891                 if (ret) {
2892                         tun_detach_filter(tun, i);
2893                         return ret;
2894                 }
2895         }
2896
2897         tun->filter_attached = true;
2898         return ret;
2899 }
2900
2901 static void tun_set_sndbuf(struct tun_struct *tun)
2902 {
2903         struct tun_file *tfile;
2904         int i;
2905
2906         for (i = 0; i < tun->numqueues; i++) {
2907                 tfile = rtnl_dereference(tun->tfiles[i]);
2908                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2909         }
2910 }
2911
2912 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2913 {
2914         struct tun_file *tfile = file->private_data;
2915         struct tun_struct *tun;
2916         int ret = 0;
2917
2918         rtnl_lock();
2919
2920         if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2921                 tun = tfile->detached;
2922                 if (!tun) {
2923                         ret = -EINVAL;
2924                         goto unlock;
2925                 }
2926                 ret = security_tun_dev_attach_queue(tun->security);
2927                 if (ret < 0)
2928                         goto unlock;
2929                 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2930                                  tun->flags & IFF_NAPI_FRAGS);
2931         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2932                 tun = rtnl_dereference(tfile->tun);
2933                 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2934                         ret = -EINVAL;
2935                 else
2936                         __tun_detach(tfile, false);
2937         } else
2938                 ret = -EINVAL;
2939
2940         if (ret >= 0)
2941                 netdev_state_change(tun->dev);
2942
2943 unlock:
2944         rtnl_unlock();
2945         return ret;
2946 }
2947
2948 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
2949                         void __user *data)
2950 {
2951         struct bpf_prog *prog;
2952         int fd;
2953
2954         if (copy_from_user(&fd, data, sizeof(fd)))
2955                 return -EFAULT;
2956
2957         if (fd == -1) {
2958                 prog = NULL;
2959         } else {
2960                 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
2961                 if (IS_ERR(prog))
2962                         return PTR_ERR(prog);
2963         }
2964
2965         return __tun_set_ebpf(tun, prog_p, prog);
2966 }
2967
2968 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2969                             unsigned long arg, int ifreq_len)
2970 {
2971         struct tun_file *tfile = file->private_data;
2972         struct net *net = sock_net(&tfile->sk);
2973         struct tun_struct *tun;
2974         void __user* argp = (void __user*)arg;
2975         struct ifreq ifr;
2976         kuid_t owner;
2977         kgid_t group;
2978         int sndbuf;
2979         int vnet_hdr_sz;
2980         unsigned int ifindex;
2981         int le;
2982         int ret;
2983         bool do_notify = false;
2984
2985         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
2986             (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
2987                 if (copy_from_user(&ifr, argp, ifreq_len))
2988                         return -EFAULT;
2989         } else {
2990                 memset(&ifr, 0, sizeof(ifr));
2991         }
2992         if (cmd == TUNGETFEATURES) {
2993                 /* Currently this just means: "what IFF flags are valid?".
2994                  * This is needed because we never checked for invalid flags on
2995                  * TUNSETIFF.
2996                  */
2997                 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2998                                 (unsigned int __user*)argp);
2999         } else if (cmd == TUNSETQUEUE) {
3000                 return tun_set_queue(file, &ifr);
3001         } else if (cmd == SIOCGSKNS) {
3002                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3003                         return -EPERM;
3004                 return open_related_ns(&net->ns, get_net_ns);
3005         }
3006
3007         ret = 0;
3008         rtnl_lock();
3009
3010         tun = tun_get(tfile);
3011         if (cmd == TUNSETIFF) {
3012                 ret = -EEXIST;
3013                 if (tun)
3014                         goto unlock;
3015
3016                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3017
3018                 ret = tun_set_iff(net, file, &ifr);
3019
3020                 if (ret)
3021                         goto unlock;
3022
3023                 if (copy_to_user(argp, &ifr, ifreq_len))
3024                         ret = -EFAULT;
3025                 goto unlock;
3026         }
3027         if (cmd == TUNSETIFINDEX) {
3028                 ret = -EPERM;
3029                 if (tun)
3030                         goto unlock;
3031
3032                 ret = -EFAULT;
3033                 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3034                         goto unlock;
3035
3036                 ret = 0;
3037                 tfile->ifindex = ifindex;
3038                 goto unlock;
3039         }
3040
3041         ret = -EBADFD;
3042         if (!tun)
3043                 goto unlock;
3044
3045         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
3046
3047         ret = 0;
3048         switch (cmd) {
3049         case TUNGETIFF:
3050                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
3051
3052                 if (tfile->detached)
3053                         ifr.ifr_flags |= IFF_DETACH_QUEUE;
3054                 if (!tfile->socket.sk->sk_filter)
3055                         ifr.ifr_flags |= IFF_NOFILTER;
3056
3057                 if (copy_to_user(argp, &ifr, ifreq_len))
3058                         ret = -EFAULT;
3059                 break;
3060
3061         case TUNSETNOCSUM:
3062                 /* Disable/Enable checksum */
3063
3064                 /* [unimplemented] */
3065                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
3066                           arg ? "disabled" : "enabled");
3067                 break;
3068
3069         case TUNSETPERSIST:
3070                 /* Disable/Enable persist mode. Keep an extra reference to the
3071                  * module to prevent the module being unprobed.
3072                  */
3073                 if (arg && !(tun->flags & IFF_PERSIST)) {
3074                         tun->flags |= IFF_PERSIST;
3075                         __module_get(THIS_MODULE);
3076                         do_notify = true;
3077                 }
3078                 if (!arg && (tun->flags & IFF_PERSIST)) {
3079                         tun->flags &= ~IFF_PERSIST;
3080                         module_put(THIS_MODULE);
3081                         do_notify = true;
3082                 }
3083
3084                 tun_debug(KERN_INFO, tun, "persist %s\n",
3085                           arg ? "enabled" : "disabled");
3086                 break;
3087
3088         case TUNSETOWNER:
3089                 /* Set owner of the device */
3090                 owner = make_kuid(current_user_ns(), arg);
3091                 if (!uid_valid(owner)) {
3092                         ret = -EINVAL;
3093                         break;
3094                 }
3095                 tun->owner = owner;
3096                 do_notify = true;
3097                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
3098                           from_kuid(&init_user_ns, tun->owner));
3099                 break;
3100
3101         case TUNSETGROUP:
3102                 /* Set group of the device */
3103                 group = make_kgid(current_user_ns(), arg);
3104                 if (!gid_valid(group)) {
3105                         ret = -EINVAL;
3106                         break;
3107                 }
3108                 tun->group = group;
3109                 do_notify = true;
3110                 tun_debug(KERN_INFO, tun, "group set to %u\n",
3111                           from_kgid(&init_user_ns, tun->group));
3112                 break;
3113
3114         case TUNSETLINK:
3115                 /* Only allow setting the type when the interface is down */
3116                 if (tun->dev->flags & IFF_UP) {
3117                         tun_debug(KERN_INFO, tun,
3118                                   "Linktype set failed because interface is up\n");
3119                         ret = -EBUSY;
3120                 } else {
3121                         tun->dev->type = (int) arg;
3122                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
3123                                   tun->dev->type);
3124                         ret = 0;
3125                 }
3126                 break;
3127
3128 #ifdef TUN_DEBUG
3129         case TUNSETDEBUG:
3130                 tun->debug = arg;
3131                 break;
3132 #endif
3133         case TUNSETOFFLOAD:
3134                 ret = set_offload(tun, arg);
3135                 break;
3136
3137         case TUNSETTXFILTER:
3138                 /* Can be set only for TAPs */
3139                 ret = -EINVAL;
3140                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3141                         break;
3142                 ret = update_filter(&tun->txflt, (void __user *)arg);
3143                 break;
3144
3145         case SIOCGIFHWADDR:
3146                 /* Get hw address */
3147                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3148                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3149                 if (copy_to_user(argp, &ifr, ifreq_len))
3150                         ret = -EFAULT;
3151                 break;
3152
3153         case SIOCSIFHWADDR:
3154                 /* Set hw address */
3155                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
3156                           ifr.ifr_hwaddr.sa_data);
3157
3158                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
3159                 break;
3160
3161         case TUNGETSNDBUF:
3162                 sndbuf = tfile->socket.sk->sk_sndbuf;
3163                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3164                         ret = -EFAULT;
3165                 break;
3166
3167         case TUNSETSNDBUF:
3168                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3169                         ret = -EFAULT;
3170                         break;
3171                 }
3172                 if (sndbuf <= 0) {
3173                         ret = -EINVAL;
3174                         break;
3175                 }
3176
3177                 tun->sndbuf = sndbuf;
3178                 tun_set_sndbuf(tun);
3179                 break;
3180
3181         case TUNGETVNETHDRSZ:
3182                 vnet_hdr_sz = tun->vnet_hdr_sz;
3183                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3184                         ret = -EFAULT;
3185                 break;
3186
3187         case TUNSETVNETHDRSZ:
3188                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3189                         ret = -EFAULT;
3190                         break;
3191                 }
3192                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3193                         ret = -EINVAL;
3194                         break;
3195                 }
3196
3197                 tun->vnet_hdr_sz = vnet_hdr_sz;
3198                 break;
3199
3200         case TUNGETVNETLE:
3201                 le = !!(tun->flags & TUN_VNET_LE);
3202                 if (put_user(le, (int __user *)argp))
3203                         ret = -EFAULT;
3204                 break;
3205
3206         case TUNSETVNETLE:
3207                 if (get_user(le, (int __user *)argp)) {
3208                         ret = -EFAULT;
3209                         break;
3210                 }
3211                 if (le)
3212                         tun->flags |= TUN_VNET_LE;
3213                 else
3214                         tun->flags &= ~TUN_VNET_LE;
3215                 break;
3216
3217         case TUNGETVNETBE:
3218                 ret = tun_get_vnet_be(tun, argp);
3219                 break;
3220
3221         case TUNSETVNETBE:
3222                 ret = tun_set_vnet_be(tun, argp);
3223                 break;
3224
3225         case TUNATTACHFILTER:
3226                 /* Can be set only for TAPs */
3227                 ret = -EINVAL;
3228                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3229                         break;
3230                 ret = -EFAULT;
3231                 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3232                         break;
3233
3234                 ret = tun_attach_filter(tun);
3235                 break;
3236
3237         case TUNDETACHFILTER:
3238                 /* Can be set only for TAPs */
3239                 ret = -EINVAL;
3240                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3241                         break;
3242                 ret = 0;
3243                 tun_detach_filter(tun, tun->numqueues);
3244                 break;
3245
3246         case TUNGETFILTER:
3247                 ret = -EINVAL;
3248                 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3249                         break;
3250                 ret = -EFAULT;
3251                 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3252                         break;
3253                 ret = 0;
3254                 break;
3255
3256         case TUNSETSTEERINGEBPF:
3257                 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3258                 break;
3259
3260         case TUNSETFILTEREBPF:
3261                 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3262                 break;
3263
3264         default:
3265                 ret = -EINVAL;
3266                 break;
3267         }
3268
3269         if (do_notify)
3270                 netdev_state_change(tun->dev);
3271
3272 unlock:
3273         rtnl_unlock();
3274         if (tun)
3275                 tun_put(tun);
3276         return ret;
3277 }
3278
3279 static long tun_chr_ioctl(struct file *file,
3280                           unsigned int cmd, unsigned long arg)
3281 {
3282         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3283 }
3284
3285 #ifdef CONFIG_COMPAT
3286 static long tun_chr_compat_ioctl(struct file *file,
3287                          unsigned int cmd, unsigned long arg)
3288 {
3289         switch (cmd) {
3290         case TUNSETIFF:
3291         case TUNGETIFF:
3292         case TUNSETTXFILTER:
3293         case TUNGETSNDBUF:
3294         case TUNSETSNDBUF:
3295         case SIOCGIFHWADDR:
3296         case SIOCSIFHWADDR:
3297                 arg = (unsigned long)compat_ptr(arg);
3298                 break;
3299         default:
3300                 arg = (compat_ulong_t)arg;
3301                 break;
3302         }
3303
3304         /*
3305          * compat_ifreq is shorter than ifreq, so we must not access beyond
3306          * the end of that structure. All fields that are used in this
3307          * driver are compatible though, we don't need to convert the
3308          * contents.
3309          */
3310         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3311 }
3312 #endif /* CONFIG_COMPAT */
3313
3314 static int tun_chr_fasync(int fd, struct file *file, int on)
3315 {
3316         struct tun_file *tfile = file->private_data;
3317         int ret;
3318
3319         if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3320                 goto out;
3321
3322         if (on) {
3323                 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3324                 tfile->flags |= TUN_FASYNC;
3325         } else
3326                 tfile->flags &= ~TUN_FASYNC;
3327         ret = 0;
3328 out:
3329         return ret;
3330 }
3331
3332 static int tun_chr_open(struct inode *inode, struct file * file)
3333 {
3334         struct net *net = current->nsproxy->net_ns;
3335         struct tun_file *tfile;
3336
3337         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
3338
3339         tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3340                                             &tun_proto, 0);
3341         if (!tfile)
3342                 return -ENOMEM;
3343         if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3344                 sk_free(&tfile->sk);
3345                 return -ENOMEM;
3346         }
3347
3348         mutex_init(&tfile->napi_mutex);
3349         RCU_INIT_POINTER(tfile->tun, NULL);
3350         tfile->flags = 0;
3351         tfile->ifindex = 0;
3352
3353         init_waitqueue_head(&tfile->wq.wait);
3354         RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
3355
3356         tfile->socket.file = file;
3357         tfile->socket.ops = &tun_socket_ops;
3358
3359         sock_init_data(&tfile->socket, &tfile->sk);
3360
3361         tfile->sk.sk_write_space = tun_sock_write_space;
3362         tfile->sk.sk_sndbuf = INT_MAX;
3363
3364         file->private_data = tfile;
3365         INIT_LIST_HEAD(&tfile->next);
3366
3367         sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3368
3369         return 0;
3370 }
3371
3372 static int tun_chr_close(struct inode *inode, struct file *file)
3373 {
3374         struct tun_file *tfile = file->private_data;
3375
3376         tun_detach(tfile, true);
3377
3378         return 0;
3379 }
3380
3381 #ifdef CONFIG_PROC_FS
3382 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3383 {
3384         struct tun_file *tfile = file->private_data;
3385         struct tun_struct *tun;
3386         struct ifreq ifr;
3387
3388         memset(&ifr, 0, sizeof(ifr));
3389
3390         rtnl_lock();
3391         tun = tun_get(tfile);
3392         if (tun)
3393                 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
3394         rtnl_unlock();
3395
3396         if (tun)
3397                 tun_put(tun);
3398
3399         seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3400 }
3401 #endif
3402
3403 static const struct file_operations tun_fops = {
3404         .owner  = THIS_MODULE,
3405         .llseek = no_llseek,
3406         .read_iter  = tun_chr_read_iter,
3407         .write_iter = tun_chr_write_iter,
3408         .poll   = tun_chr_poll,
3409         .unlocked_ioctl = tun_chr_ioctl,
3410 #ifdef CONFIG_COMPAT
3411         .compat_ioctl = tun_chr_compat_ioctl,
3412 #endif
3413         .open   = tun_chr_open,
3414         .release = tun_chr_close,
3415         .fasync = tun_chr_fasync,
3416 #ifdef CONFIG_PROC_FS
3417         .show_fdinfo = tun_chr_show_fdinfo,
3418 #endif
3419 };
3420
3421 static struct miscdevice tun_miscdev = {
3422         .minor = TUN_MINOR,
3423         .name = "tun",
3424         .nodename = "net/tun",
3425         .fops = &tun_fops,
3426 };
3427
3428 /* ethtool interface */
3429
3430 static void tun_default_link_ksettings(struct net_device *dev,
3431                                        struct ethtool_link_ksettings *cmd)
3432 {
3433         ethtool_link_ksettings_zero_link_mode(cmd, supported);
3434         ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3435         cmd->base.speed         = SPEED_10;
3436         cmd->base.duplex        = DUPLEX_FULL;
3437         cmd->base.port          = PORT_TP;
3438         cmd->base.phy_address   = 0;
3439         cmd->base.autoneg       = AUTONEG_DISABLE;
3440 }
3441
3442 static int tun_get_link_ksettings(struct net_device *dev,
3443                                   struct ethtool_link_ksettings *cmd)
3444 {
3445         struct tun_struct *tun = netdev_priv(dev);
3446
3447         memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3448         return 0;
3449 }
3450
3451 static int tun_set_link_ksettings(struct net_device *dev,
3452                                   const struct ethtool_link_ksettings *cmd)
3453 {
3454         struct tun_struct *tun = netdev_priv(dev);
3455
3456         memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3457         return 0;
3458 }
3459
3460 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3461 {
3462         struct tun_struct *tun = netdev_priv(dev);
3463
3464         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3465         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3466
3467         switch (tun->flags & TUN_TYPE_MASK) {
3468         case IFF_TUN:
3469                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3470                 break;
3471         case IFF_TAP:
3472                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3473                 break;
3474         }
3475 }
3476
3477 static u32 tun_get_msglevel(struct net_device *dev)
3478 {
3479 #ifdef TUN_DEBUG
3480         struct tun_struct *tun = netdev_priv(dev);
3481         return tun->debug;
3482 #else
3483         return -EOPNOTSUPP;
3484 #endif
3485 }
3486
3487 static void tun_set_msglevel(struct net_device *dev, u32 value)
3488 {
3489 #ifdef TUN_DEBUG
3490         struct tun_struct *tun = netdev_priv(dev);
3491         tun->debug = value;
3492 #endif
3493 }
3494
3495 static int tun_get_coalesce(struct net_device *dev,
3496                             struct ethtool_coalesce *ec)
3497 {
3498         struct tun_struct *tun = netdev_priv(dev);
3499
3500         ec->rx_max_coalesced_frames = tun->rx_batched;
3501
3502         return 0;
3503 }
3504
3505 static int tun_set_coalesce(struct net_device *dev,
3506                             struct ethtool_coalesce *ec)
3507 {
3508         struct tun_struct *tun = netdev_priv(dev);
3509
3510         if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3511                 tun->rx_batched = NAPI_POLL_WEIGHT;
3512         else
3513                 tun->rx_batched = ec->rx_max_coalesced_frames;
3514
3515         return 0;
3516 }
3517
3518 static const struct ethtool_ops tun_ethtool_ops = {
3519         .get_drvinfo    = tun_get_drvinfo,
3520         .get_msglevel   = tun_get_msglevel,
3521         .set_msglevel   = tun_set_msglevel,
3522         .get_link       = ethtool_op_get_link,
3523         .get_ts_info    = ethtool_op_get_ts_info,
3524         .get_coalesce   = tun_get_coalesce,
3525         .set_coalesce   = tun_set_coalesce,
3526         .get_link_ksettings = tun_get_link_ksettings,
3527         .set_link_ksettings = tun_set_link_ksettings,
3528 };
3529
3530 static int tun_queue_resize(struct tun_struct *tun)
3531 {
3532         struct net_device *dev = tun->dev;
3533         struct tun_file *tfile;
3534         struct ptr_ring **rings;
3535         int n = tun->numqueues + tun->numdisabled;
3536         int ret, i;
3537
3538         rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3539         if (!rings)
3540                 return -ENOMEM;
3541
3542         for (i = 0; i < tun->numqueues; i++) {
3543                 tfile = rtnl_dereference(tun->tfiles[i]);
3544                 rings[i] = &tfile->tx_ring;
3545         }
3546         list_for_each_entry(tfile, &tun->disabled, next)
3547                 rings[i++] = &tfile->tx_ring;
3548
3549         ret = ptr_ring_resize_multiple(rings, n,
3550                                        dev->tx_queue_len, GFP_KERNEL,
3551                                        tun_ptr_free);
3552
3553         kfree(rings);
3554         return ret;
3555 }
3556
3557 static int tun_device_event(struct notifier_block *unused,
3558                             unsigned long event, void *ptr)
3559 {
3560         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3561         struct tun_struct *tun = netdev_priv(dev);
3562
3563         if (dev->rtnl_link_ops != &tun_link_ops)
3564                 return NOTIFY_DONE;
3565
3566         switch (event) {
3567         case NETDEV_CHANGE_TX_QUEUE_LEN:
3568                 if (tun_queue_resize(tun))
3569                         return NOTIFY_BAD;
3570                 break;
3571         default:
3572                 break;
3573         }
3574
3575         return NOTIFY_DONE;
3576 }
3577
3578 static struct notifier_block tun_notifier_block __read_mostly = {
3579         .notifier_call  = tun_device_event,
3580 };
3581
3582 static int __init tun_init(void)
3583 {
3584         int ret = 0;
3585
3586         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3587
3588         ret = rtnl_link_register(&tun_link_ops);
3589         if (ret) {
3590                 pr_err("Can't register link_ops\n");
3591                 goto err_linkops;
3592         }
3593
3594         ret = misc_register(&tun_miscdev);
3595         if (ret) {
3596                 pr_err("Can't register misc device %d\n", TUN_MINOR);
3597                 goto err_misc;
3598         }
3599
3600         ret = register_netdevice_notifier(&tun_notifier_block);
3601         if (ret) {
3602                 pr_err("Can't register netdevice notifier\n");
3603                 goto err_notifier;
3604         }
3605
3606         return  0;
3607
3608 err_notifier:
3609         misc_deregister(&tun_miscdev);
3610 err_misc:
3611         rtnl_link_unregister(&tun_link_ops);
3612 err_linkops:
3613         return ret;
3614 }
3615
3616 static void tun_cleanup(void)
3617 {
3618         misc_deregister(&tun_miscdev);
3619         rtnl_link_unregister(&tun_link_ops);
3620         unregister_netdevice_notifier(&tun_notifier_block);
3621 }
3622
3623 /* Get an underlying socket object from tun file.  Returns error unless file is
3624  * attached to a device.  The returned object works like a packet socket, it
3625  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
3626  * holding a reference to the file for as long as the socket is in use. */
3627 struct socket *tun_get_socket(struct file *file)
3628 {
3629         struct tun_file *tfile;
3630         if (file->f_op != &tun_fops)
3631                 return ERR_PTR(-EINVAL);
3632         tfile = file->private_data;
3633         if (!tfile)
3634                 return ERR_PTR(-EBADFD);
3635         return &tfile->socket;
3636 }
3637 EXPORT_SYMBOL_GPL(tun_get_socket);
3638
3639 struct ptr_ring *tun_get_tx_ring(struct file *file)
3640 {
3641         struct tun_file *tfile;
3642
3643         if (file->f_op != &tun_fops)
3644                 return ERR_PTR(-EINVAL);
3645         tfile = file->private_data;
3646         if (!tfile)
3647                 return ERR_PTR(-EBADFD);
3648         return &tfile->tx_ring;
3649 }
3650 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3651
3652 module_init(tun_init);
3653 module_exit(tun_cleanup);
3654 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3655 MODULE_AUTHOR(DRV_COPYRIGHT);
3656 MODULE_LICENSE("GPL");
3657 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3658 MODULE_ALIAS("devname:net/tun");