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 <linux/seq_file.h> 74 #include <linux/uio.h> 75 #include <linux/skb_array.h> 76 #include <linux/bpf.h> 77 #include <linux/bpf_trace.h> 78 #include <linux/mutex.h> 79 80 #include <linux/uaccess.h> 81 #include <linux/proc_fs.h> 82 83 /* Uncomment to enable debugging */ 84 /* #define TUN_DEBUG 1 */ 85 86 #ifdef TUN_DEBUG 87 static int debug; 88 89 #define tun_debug(level, tun, fmt, args...) \ 90 do { \ 91 if (tun->debug) \ 92 netdev_printk(level, tun->dev, fmt, ##args); \ 93 } while (0) 94 #define DBG1(level, fmt, args...) \ 95 do { \ 96 if (debug == 2) \ 97 printk(level fmt, ##args); \ 98 } while (0) 99 #else 100 #define tun_debug(level, tun, fmt, args...) \ 101 do { \ 102 if (0) \ 103 netdev_printk(level, tun->dev, fmt, ##args); \ 104 } while (0) 105 #define DBG1(level, fmt, args...) \ 106 do { \ 107 if (0) \ 108 printk(level fmt, ##args); \ 109 } while (0) 110 #endif 111 112 #define TUN_HEADROOM 256 113 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD) 114 115 /* TUN device flags */ 116 117 /* IFF_ATTACH_QUEUE is never stored in device flags, 118 * overload it to mean fasync when stored there. 119 */ 120 #define TUN_FASYNC IFF_ATTACH_QUEUE 121 /* High bits in flags field are unused. */ 122 #define TUN_VNET_LE 0x80000000 123 #define TUN_VNET_BE 0x40000000 124 125 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \ 126 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS) 127 128 #define GOODCOPY_LEN 128 129 130 #define FLT_EXACT_COUNT 8 131 struct tap_filter { 132 unsigned int count; /* Number of addrs. Zero means disabled */ 133 u32 mask[2]; /* Mask of the hashed addrs */ 134 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 135 }; 136 137 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal 138 * to max number of VCPUs in guest. */ 139 #define MAX_TAP_QUEUES 256 140 #define MAX_TAP_FLOWS 4096 141 142 #define TUN_FLOW_EXPIRE (3 * HZ) 143 144 struct tun_pcpu_stats { 145 u64 rx_packets; 146 u64 rx_bytes; 147 u64 tx_packets; 148 u64 tx_bytes; 149 struct u64_stats_sync syncp; 150 u32 rx_dropped; 151 u32 tx_dropped; 152 u32 rx_frame_errors; 153 }; 154 155 /* A tun_file connects an open character device to a tuntap netdevice. It 156 * also contains all socket related structures (except sock_fprog and tap_filter) 157 * to serve as one transmit queue for tuntap device. The sock_fprog and 158 * tap_filter were kept in tun_struct since they were used for filtering for the 159 * netdevice not for a specific queue (at least I didn't see the requirement for 160 * this). 161 * 162 * RCU usage: 163 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 164 * other can only be read while rcu_read_lock or rtnl_lock is held. 165 */ 166 struct tun_file { 167 struct sock sk; 168 struct socket socket; 169 struct socket_wq wq; 170 struct tun_struct __rcu *tun; 171 struct fasync_struct *fasync; 172 /* only used for fasnyc */ 173 unsigned int flags; 174 union { 175 u16 queue_index; 176 unsigned int ifindex; 177 }; 178 struct napi_struct napi; 179 bool napi_enabled; 180 struct mutex napi_mutex; /* Protects access to the above napi */ 181 struct list_head next; 182 struct tun_struct *detached; 183 struct ptr_ring tx_ring; 184 struct xdp_rxq_info xdp_rxq; 185 int xdp_pending_pkts; 186 }; 187 188 struct tun_flow_entry { 189 struct hlist_node hash_link; 190 struct rcu_head rcu; 191 struct tun_struct *tun; 192 193 u32 rxhash; 194 u32 rps_rxhash; 195 int queue_index; 196 unsigned long updated; 197 }; 198 199 #define TUN_NUM_FLOW_ENTRIES 1024 200 201 struct tun_prog { 202 struct rcu_head rcu; 203 struct bpf_prog *prog; 204 }; 205 206 /* Since the socket were moved to tun_file, to preserve the behavior of persist 207 * device, socket filter, sndbuf and vnet header size were restore when the 208 * file were attached to a persist device. 209 */ 210 struct tun_struct { 211 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 212 unsigned int numqueues; 213 unsigned int flags; 214 kuid_t owner; 215 kgid_t group; 216 217 struct net_device *dev; 218 netdev_features_t set_features; 219 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 220 NETIF_F_TSO6) 221 222 int align; 223 int vnet_hdr_sz; 224 int sndbuf; 225 struct tap_filter txflt; 226 struct sock_fprog fprog; 227 /* protected by rtnl lock */ 228 bool filter_attached; 229 #ifdef TUN_DEBUG 230 int debug; 231 #endif 232 spinlock_t lock; 233 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 234 struct timer_list flow_gc_timer; 235 unsigned long ageing_time; 236 unsigned int numdisabled; 237 struct list_head disabled; 238 void *security; 239 u32 flow_count; 240 u32 rx_batched; 241 struct tun_pcpu_stats __percpu *pcpu_stats; 242 struct bpf_prog __rcu *xdp_prog; 243 struct tun_prog __rcu *steering_prog; 244 struct tun_prog __rcu *filter_prog; 245 }; 246 247 struct veth { 248 __be16 h_vlan_proto; 249 __be16 h_vlan_TCI; 250 }; 251 252 bool tun_is_xdp_buff(void *ptr) 253 { 254 return (unsigned long)ptr & TUN_XDP_FLAG; 255 } 256 EXPORT_SYMBOL(tun_is_xdp_buff); 257 258 void *tun_xdp_to_ptr(void *ptr) 259 { 260 return (void *)((unsigned long)ptr | TUN_XDP_FLAG); 261 } 262 EXPORT_SYMBOL(tun_xdp_to_ptr); 263 264 void *tun_ptr_to_xdp(void *ptr) 265 { 266 return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG); 267 } 268 EXPORT_SYMBOL(tun_ptr_to_xdp); 269 270 static int tun_napi_receive(struct napi_struct *napi, int budget) 271 { 272 struct tun_file *tfile = container_of(napi, struct tun_file, napi); 273 struct sk_buff_head *queue = &tfile->sk.sk_write_queue; 274 struct sk_buff_head process_queue; 275 struct sk_buff *skb; 276 int received = 0; 277 278 __skb_queue_head_init(&process_queue); 279 280 spin_lock(&queue->lock); 281 skb_queue_splice_tail_init(queue, &process_queue); 282 spin_unlock(&queue->lock); 283 284 while (received < budget && (skb = __skb_dequeue(&process_queue))) { 285 napi_gro_receive(napi, skb); 286 ++received; 287 } 288 289 if (!skb_queue_empty(&process_queue)) { 290 spin_lock(&queue->lock); 291 skb_queue_splice(&process_queue, queue); 292 spin_unlock(&queue->lock); 293 } 294 295 return received; 296 } 297 298 static int tun_napi_poll(struct napi_struct *napi, int budget) 299 { 300 unsigned int received; 301 302 received = tun_napi_receive(napi, budget); 303 304 if (received < budget) 305 napi_complete_done(napi, received); 306 307 return received; 308 } 309 310 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile, 311 bool napi_en) 312 { 313 tfile->napi_enabled = napi_en; 314 if (napi_en) { 315 netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll, 316 NAPI_POLL_WEIGHT); 317 napi_enable(&tfile->napi); 318 mutex_init(&tfile->napi_mutex); 319 } 320 } 321 322 static void tun_napi_disable(struct tun_struct *tun, struct tun_file *tfile) 323 { 324 if (tfile->napi_enabled) 325 napi_disable(&tfile->napi); 326 } 327 328 static void tun_napi_del(struct tun_struct *tun, struct tun_file *tfile) 329 { 330 if (tfile->napi_enabled) 331 netif_napi_del(&tfile->napi); 332 } 333 334 static bool tun_napi_frags_enabled(const struct tun_struct *tun) 335 { 336 return READ_ONCE(tun->flags) & IFF_NAPI_FRAGS; 337 } 338 339 #ifdef CONFIG_TUN_VNET_CROSS_LE 340 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun) 341 { 342 return tun->flags & TUN_VNET_BE ? false : 343 virtio_legacy_is_little_endian(); 344 } 345 346 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp) 347 { 348 int be = !!(tun->flags & TUN_VNET_BE); 349 350 if (put_user(be, argp)) 351 return -EFAULT; 352 353 return 0; 354 } 355 356 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp) 357 { 358 int be; 359 360 if (get_user(be, argp)) 361 return -EFAULT; 362 363 if (be) 364 tun->flags |= TUN_VNET_BE; 365 else 366 tun->flags &= ~TUN_VNET_BE; 367 368 return 0; 369 } 370 #else 371 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun) 372 { 373 return virtio_legacy_is_little_endian(); 374 } 375 376 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp) 377 { 378 return -EINVAL; 379 } 380 381 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp) 382 { 383 return -EINVAL; 384 } 385 #endif /* CONFIG_TUN_VNET_CROSS_LE */ 386 387 static inline bool tun_is_little_endian(struct tun_struct *tun) 388 { 389 return tun->flags & TUN_VNET_LE || 390 tun_legacy_is_little_endian(tun); 391 } 392 393 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) 394 { 395 return __virtio16_to_cpu(tun_is_little_endian(tun), val); 396 } 397 398 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val) 399 { 400 return __cpu_to_virtio16(tun_is_little_endian(tun), val); 401 } 402 403 static inline u32 tun_hashfn(u32 rxhash) 404 { 405 return rxhash & 0x3ff; 406 } 407 408 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 409 { 410 struct tun_flow_entry *e; 411 412 hlist_for_each_entry_rcu(e, head, hash_link) { 413 if (e->rxhash == rxhash) 414 return e; 415 } 416 return NULL; 417 } 418 419 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 420 struct hlist_head *head, 421 u32 rxhash, u16 queue_index) 422 { 423 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 424 425 if (e) { 426 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 427 rxhash, queue_index); 428 e->updated = jiffies; 429 e->rxhash = rxhash; 430 e->rps_rxhash = 0; 431 e->queue_index = queue_index; 432 e->tun = tun; 433 hlist_add_head_rcu(&e->hash_link, head); 434 ++tun->flow_count; 435 } 436 return e; 437 } 438 439 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 440 { 441 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 442 e->rxhash, e->queue_index); 443 hlist_del_rcu(&e->hash_link); 444 kfree_rcu(e, rcu); 445 --tun->flow_count; 446 } 447 448 static void tun_flow_flush(struct tun_struct *tun) 449 { 450 int i; 451 452 spin_lock_bh(&tun->lock); 453 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 454 struct tun_flow_entry *e; 455 struct hlist_node *n; 456 457 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 458 tun_flow_delete(tun, e); 459 } 460 spin_unlock_bh(&tun->lock); 461 } 462 463 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 464 { 465 int i; 466 467 spin_lock_bh(&tun->lock); 468 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 469 struct tun_flow_entry *e; 470 struct hlist_node *n; 471 472 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 473 if (e->queue_index == queue_index) 474 tun_flow_delete(tun, e); 475 } 476 } 477 spin_unlock_bh(&tun->lock); 478 } 479 480 static void tun_flow_cleanup(struct timer_list *t) 481 { 482 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer); 483 unsigned long delay = tun->ageing_time; 484 unsigned long next_timer = jiffies + delay; 485 unsigned long count = 0; 486 int i; 487 488 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 489 490 spin_lock(&tun->lock); 491 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 492 struct tun_flow_entry *e; 493 struct hlist_node *n; 494 495 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 496 unsigned long this_timer; 497 498 this_timer = e->updated + delay; 499 if (time_before_eq(this_timer, jiffies)) { 500 tun_flow_delete(tun, e); 501 continue; 502 } 503 count++; 504 if (time_before(this_timer, next_timer)) 505 next_timer = this_timer; 506 } 507 } 508 509 if (count) 510 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 511 spin_unlock(&tun->lock); 512 } 513 514 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 515 struct tun_file *tfile) 516 { 517 struct hlist_head *head; 518 struct tun_flow_entry *e; 519 unsigned long delay = tun->ageing_time; 520 u16 queue_index = tfile->queue_index; 521 522 if (!rxhash) 523 return; 524 else 525 head = &tun->flows[tun_hashfn(rxhash)]; 526 527 rcu_read_lock(); 528 529 /* We may get a very small possibility of OOO during switching, not 530 * worth to optimize.*/ 531 if (tun->numqueues == 1 || tfile->detached) 532 goto unlock; 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 unlock: 553 rcu_read_unlock(); 554 } 555 556 /** 557 * Save the hash received in the stack receive path and update the 558 * flow_hash table accordingly. 559 */ 560 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 561 { 562 if (unlikely(e->rps_rxhash != hash)) 563 e->rps_rxhash = hash; 564 } 565 566 /* We try to identify a flow through its rxhash first. The reason that 567 * we do not check rxq no. is because some cards(e.g 82599), chooses 568 * the rxq based on the txq where the last packet of the flow comes. As 569 * the userspace application move between processors, we may get a 570 * different rxq no. here. If we could not get rxhash, then we would 571 * hope the rxq no. may help here. 572 */ 573 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb) 574 { 575 struct tun_flow_entry *e; 576 u32 txq = 0; 577 u32 numqueues = 0; 578 579 numqueues = READ_ONCE(tun->numqueues); 580 581 txq = __skb_get_hash_symmetric(skb); 582 if (txq) { 583 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 584 if (e) { 585 tun_flow_save_rps_rxhash(e, txq); 586 txq = e->queue_index; 587 } else 588 /* use multiply and shift instead of expensive divide */ 589 txq = ((u64)txq * numqueues) >> 32; 590 } else if (likely(skb_rx_queue_recorded(skb))) { 591 txq = skb_get_rx_queue(skb); 592 while (unlikely(txq >= numqueues)) 593 txq -= numqueues; 594 } 595 596 return txq; 597 } 598 599 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb) 600 { 601 struct tun_prog *prog; 602 u16 ret = 0; 603 604 prog = rcu_dereference(tun->steering_prog); 605 if (prog) 606 ret = bpf_prog_run_clear_cb(prog->prog, skb); 607 608 return ret % tun->numqueues; 609 } 610 611 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, 612 void *accel_priv, select_queue_fallback_t fallback) 613 { 614 struct tun_struct *tun = netdev_priv(dev); 615 u16 ret; 616 617 rcu_read_lock(); 618 if (rcu_dereference(tun->steering_prog)) 619 ret = tun_ebpf_select_queue(tun, skb); 620 else 621 ret = tun_automq_select_queue(tun, skb); 622 rcu_read_unlock(); 623 624 return ret; 625 } 626 627 static inline bool tun_not_capable(struct tun_struct *tun) 628 { 629 const struct cred *cred = current_cred(); 630 struct net *net = dev_net(tun->dev); 631 632 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 633 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 634 !ns_capable(net->user_ns, CAP_NET_ADMIN); 635 } 636 637 static void tun_set_real_num_queues(struct tun_struct *tun) 638 { 639 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 640 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 641 } 642 643 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 644 { 645 tfile->detached = tun; 646 list_add_tail(&tfile->next, &tun->disabled); 647 ++tun->numdisabled; 648 } 649 650 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 651 { 652 struct tun_struct *tun = tfile->detached; 653 654 tfile->detached = NULL; 655 list_del_init(&tfile->next); 656 --tun->numdisabled; 657 return tun; 658 } 659 660 static void tun_ptr_free(void *ptr) 661 { 662 if (!ptr) 663 return; 664 if (tun_is_xdp_buff(ptr)) { 665 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr); 666 667 put_page(virt_to_head_page(xdp->data)); 668 } else { 669 __skb_array_destroy_skb(ptr); 670 } 671 } 672 673 static void tun_queue_purge(struct tun_file *tfile) 674 { 675 void *ptr; 676 677 while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL) 678 tun_ptr_free(ptr); 679 680 skb_queue_purge(&tfile->sk.sk_write_queue); 681 skb_queue_purge(&tfile->sk.sk_error_queue); 682 } 683 684 static void tun_cleanup_tx_ring(struct tun_file *tfile) 685 { 686 if (tfile->tx_ring.queue) { 687 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free); 688 xdp_rxq_info_unreg(&tfile->xdp_rxq); 689 memset(&tfile->tx_ring, 0, sizeof(tfile->tx_ring)); 690 } 691 } 692 693 static void __tun_detach(struct tun_file *tfile, bool clean) 694 { 695 struct tun_file *ntfile; 696 struct tun_struct *tun; 697 698 tun = rtnl_dereference(tfile->tun); 699 700 if (tun && clean) { 701 tun_napi_disable(tun, tfile); 702 tun_napi_del(tun, tfile); 703 } 704 705 if (tun && !tfile->detached) { 706 u16 index = tfile->queue_index; 707 BUG_ON(index >= tun->numqueues); 708 709 rcu_assign_pointer(tun->tfiles[index], 710 tun->tfiles[tun->numqueues - 1]); 711 ntfile = rtnl_dereference(tun->tfiles[index]); 712 ntfile->queue_index = index; 713 714 --tun->numqueues; 715 if (clean) { 716 RCU_INIT_POINTER(tfile->tun, NULL); 717 sock_put(&tfile->sk); 718 } else 719 tun_disable_queue(tun, tfile); 720 721 synchronize_net(); 722 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 723 /* Drop read queue */ 724 tun_queue_purge(tfile); 725 tun_set_real_num_queues(tun); 726 } else if (tfile->detached && clean) { 727 tun = tun_enable_queue(tfile); 728 sock_put(&tfile->sk); 729 } 730 731 if (clean) { 732 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 733 netif_carrier_off(tun->dev); 734 735 if (!(tun->flags & IFF_PERSIST) && 736 tun->dev->reg_state == NETREG_REGISTERED) 737 unregister_netdevice(tun->dev); 738 } 739 tun_cleanup_tx_ring(tfile); 740 sock_put(&tfile->sk); 741 } 742 } 743 744 static void tun_detach(struct tun_file *tfile, bool clean) 745 { 746 rtnl_lock(); 747 __tun_detach(tfile, clean); 748 rtnl_unlock(); 749 } 750 751 static void tun_detach_all(struct net_device *dev) 752 { 753 struct tun_struct *tun = netdev_priv(dev); 754 struct tun_file *tfile, *tmp; 755 int i, n = tun->numqueues; 756 757 for (i = 0; i < n; i++) { 758 tfile = rtnl_dereference(tun->tfiles[i]); 759 BUG_ON(!tfile); 760 tun_napi_disable(tun, tfile); 761 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN; 762 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 763 RCU_INIT_POINTER(tfile->tun, NULL); 764 --tun->numqueues; 765 } 766 list_for_each_entry(tfile, &tun->disabled, next) { 767 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN; 768 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 769 RCU_INIT_POINTER(tfile->tun, NULL); 770 } 771 BUG_ON(tun->numqueues != 0); 772 773 synchronize_net(); 774 for (i = 0; i < n; i++) { 775 tfile = rtnl_dereference(tun->tfiles[i]); 776 tun_napi_del(tun, tfile); 777 /* Drop read queue */ 778 tun_queue_purge(tfile); 779 sock_put(&tfile->sk); 780 tun_cleanup_tx_ring(tfile); 781 } 782 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 783 tun_enable_queue(tfile); 784 tun_queue_purge(tfile); 785 sock_put(&tfile->sk); 786 tun_cleanup_tx_ring(tfile); 787 } 788 BUG_ON(tun->numdisabled != 0); 789 790 if (tun->flags & IFF_PERSIST) 791 module_put(THIS_MODULE); 792 } 793 794 static int tun_attach(struct tun_struct *tun, struct file *file, 795 bool skip_filter, bool napi) 796 { 797 struct tun_file *tfile = file->private_data; 798 struct net_device *dev = tun->dev; 799 int err; 800 801 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 802 if (err < 0) 803 goto out; 804 805 err = -EINVAL; 806 if (rtnl_dereference(tfile->tun) && !tfile->detached) 807 goto out; 808 809 err = -EBUSY; 810 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1) 811 goto out; 812 813 err = -E2BIG; 814 if (!tfile->detached && 815 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 816 goto out; 817 818 err = 0; 819 820 /* Re-attach the filter to persist device */ 821 if (!skip_filter && (tun->filter_attached == true)) { 822 lock_sock(tfile->socket.sk); 823 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 824 release_sock(tfile->socket.sk); 825 if (!err) 826 goto out; 827 } 828 829 if (!tfile->detached && 830 ptr_ring_init(&tfile->tx_ring, dev->tx_queue_len, GFP_KERNEL)) { 831 err = -ENOMEM; 832 goto out; 833 } 834 835 tfile->queue_index = tun->numqueues; 836 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN; 837 838 if (tfile->detached) { 839 /* Re-attach detached tfile, updating XDP queue_index */ 840 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq)); 841 842 if (tfile->xdp_rxq.queue_index != tfile->queue_index) 843 tfile->xdp_rxq.queue_index = tfile->queue_index; 844 } else { 845 /* Setup XDP RX-queue info, for new tfile getting attached */ 846 err = xdp_rxq_info_reg(&tfile->xdp_rxq, 847 tun->dev, tfile->queue_index); 848 if (err < 0) 849 goto out; 850 err = 0; 851 } 852 853 rcu_assign_pointer(tfile->tun, tun); 854 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 855 tun->numqueues++; 856 857 if (tfile->detached) { 858 tun_enable_queue(tfile); 859 } else { 860 sock_hold(&tfile->sk); 861 tun_napi_init(tun, tfile, napi); 862 } 863 864 tun_set_real_num_queues(tun); 865 866 /* device is allowed to go away first, so no need to hold extra 867 * refcnt. 868 */ 869 870 out: 871 return err; 872 } 873 874 static struct tun_struct *tun_get(struct tun_file *tfile) 875 { 876 struct tun_struct *tun; 877 878 rcu_read_lock(); 879 tun = rcu_dereference(tfile->tun); 880 if (tun) 881 dev_hold(tun->dev); 882 rcu_read_unlock(); 883 884 return tun; 885 } 886 887 static void tun_put(struct tun_struct *tun) 888 { 889 dev_put(tun->dev); 890 } 891 892 /* TAP filtering */ 893 static void addr_hash_set(u32 *mask, const u8 *addr) 894 { 895 int n = ether_crc(ETH_ALEN, addr) >> 26; 896 mask[n >> 5] |= (1 << (n & 31)); 897 } 898 899 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 900 { 901 int n = ether_crc(ETH_ALEN, addr) >> 26; 902 return mask[n >> 5] & (1 << (n & 31)); 903 } 904 905 static int update_filter(struct tap_filter *filter, void __user *arg) 906 { 907 struct { u8 u[ETH_ALEN]; } *addr; 908 struct tun_filter uf; 909 int err, alen, n, nexact; 910 911 if (copy_from_user(&uf, arg, sizeof(uf))) 912 return -EFAULT; 913 914 if (!uf.count) { 915 /* Disabled */ 916 filter->count = 0; 917 return 0; 918 } 919 920 alen = ETH_ALEN * uf.count; 921 addr = memdup_user(arg + sizeof(uf), alen); 922 if (IS_ERR(addr)) 923 return PTR_ERR(addr); 924 925 /* The filter is updated without holding any locks. Which is 926 * perfectly safe. We disable it first and in the worst 927 * case we'll accept a few undesired packets. */ 928 filter->count = 0; 929 wmb(); 930 931 /* Use first set of addresses as an exact filter */ 932 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 933 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 934 935 nexact = n; 936 937 /* Remaining multicast addresses are hashed, 938 * unicast will leave the filter disabled. */ 939 memset(filter->mask, 0, sizeof(filter->mask)); 940 for (; n < uf.count; n++) { 941 if (!is_multicast_ether_addr(addr[n].u)) { 942 err = 0; /* no filter */ 943 goto free_addr; 944 } 945 addr_hash_set(filter->mask, addr[n].u); 946 } 947 948 /* For ALLMULTI just set the mask to all ones. 949 * This overrides the mask populated above. */ 950 if ((uf.flags & TUN_FLT_ALLMULTI)) 951 memset(filter->mask, ~0, sizeof(filter->mask)); 952 953 /* Now enable the filter */ 954 wmb(); 955 filter->count = nexact; 956 957 /* Return the number of exact filters */ 958 err = nexact; 959 free_addr: 960 kfree(addr); 961 return err; 962 } 963 964 /* Returns: 0 - drop, !=0 - accept */ 965 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 966 { 967 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 968 * at this point. */ 969 struct ethhdr *eh = (struct ethhdr *) skb->data; 970 int i; 971 972 /* Exact match */ 973 for (i = 0; i < filter->count; i++) 974 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 975 return 1; 976 977 /* Inexact match (multicast only) */ 978 if (is_multicast_ether_addr(eh->h_dest)) 979 return addr_hash_test(filter->mask, eh->h_dest); 980 981 return 0; 982 } 983 984 /* 985 * Checks whether the packet is accepted or not. 986 * Returns: 0 - drop, !=0 - accept 987 */ 988 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 989 { 990 if (!filter->count) 991 return 1; 992 993 return run_filter(filter, skb); 994 } 995 996 /* Network device part of the driver */ 997 998 static const struct ethtool_ops tun_ethtool_ops; 999 1000 /* Net device detach from fd. */ 1001 static void tun_net_uninit(struct net_device *dev) 1002 { 1003 tun_detach_all(dev); 1004 } 1005 1006 /* Net device open. */ 1007 static int tun_net_open(struct net_device *dev) 1008 { 1009 struct tun_struct *tun = netdev_priv(dev); 1010 int i; 1011 1012 netif_tx_start_all_queues(dev); 1013 1014 for (i = 0; i < tun->numqueues; i++) { 1015 struct tun_file *tfile; 1016 1017 tfile = rtnl_dereference(tun->tfiles[i]); 1018 tfile->socket.sk->sk_write_space(tfile->socket.sk); 1019 } 1020 1021 return 0; 1022 } 1023 1024 /* Net device close. */ 1025 static int tun_net_close(struct net_device *dev) 1026 { 1027 netif_tx_stop_all_queues(dev); 1028 return 0; 1029 } 1030 1031 /* Net device start xmit */ 1032 static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb) 1033 { 1034 #ifdef CONFIG_RPS 1035 if (tun->numqueues == 1 && static_key_false(&rps_needed)) { 1036 /* Select queue was not called for the skbuff, so we extract the 1037 * RPS hash and save it into the flow_table here. 1038 */ 1039 __u32 rxhash; 1040 1041 rxhash = __skb_get_hash_symmetric(skb); 1042 if (rxhash) { 1043 struct tun_flow_entry *e; 1044 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], 1045 rxhash); 1046 if (e) 1047 tun_flow_save_rps_rxhash(e, rxhash); 1048 } 1049 } 1050 #endif 1051 } 1052 1053 static unsigned int run_ebpf_filter(struct tun_struct *tun, 1054 struct sk_buff *skb, 1055 int len) 1056 { 1057 struct tun_prog *prog = rcu_dereference(tun->filter_prog); 1058 1059 if (prog) 1060 len = bpf_prog_run_clear_cb(prog->prog, skb); 1061 1062 return len; 1063 } 1064 1065 /* Net device start xmit */ 1066 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 1067 { 1068 struct tun_struct *tun = netdev_priv(dev); 1069 int txq = skb->queue_mapping; 1070 struct tun_file *tfile; 1071 int len = skb->len; 1072 1073 rcu_read_lock(); 1074 tfile = rcu_dereference(tun->tfiles[txq]); 1075 1076 /* Drop packet if interface is not attached */ 1077 if (txq >= tun->numqueues) 1078 goto drop; 1079 1080 if (!rcu_dereference(tun->steering_prog)) 1081 tun_automq_xmit(tun, skb); 1082 1083 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 1084 1085 BUG_ON(!tfile); 1086 1087 /* Drop if the filter does not like it. 1088 * This is a noop if the filter is disabled. 1089 * Filter can be enabled only for the TAP devices. */ 1090 if (!check_filter(&tun->txflt, skb)) 1091 goto drop; 1092 1093 if (tfile->socket.sk->sk_filter && 1094 sk_filter(tfile->socket.sk, skb)) 1095 goto drop; 1096 1097 len = run_ebpf_filter(tun, skb, len); 1098 1099 /* Trim extra bytes since we may insert vlan proto & TCI 1100 * in tun_put_user(). 1101 */ 1102 len -= skb_vlan_tag_present(skb) ? sizeof(struct veth) : 0; 1103 if (len <= 0 || pskb_trim(skb, len)) 1104 goto drop; 1105 1106 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) 1107 goto drop; 1108 1109 skb_tx_timestamp(skb); 1110 1111 /* Orphan the skb - required as we might hang on to it 1112 * for indefinite time. 1113 */ 1114 skb_orphan(skb); 1115 1116 nf_reset(skb); 1117 1118 if (ptr_ring_produce(&tfile->tx_ring, skb)) 1119 goto drop; 1120 1121 /* Notify and wake up reader process */ 1122 if (tfile->flags & TUN_FASYNC) 1123 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 1124 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 1125 1126 rcu_read_unlock(); 1127 return NETDEV_TX_OK; 1128 1129 drop: 1130 this_cpu_inc(tun->pcpu_stats->tx_dropped); 1131 skb_tx_error(skb); 1132 kfree_skb(skb); 1133 rcu_read_unlock(); 1134 return NET_XMIT_DROP; 1135 } 1136 1137 static void tun_net_mclist(struct net_device *dev) 1138 { 1139 /* 1140 * This callback is supposed to deal with mc filter in 1141 * _rx_ path and has nothing to do with the _tx_ path. 1142 * In rx path we always accept everything userspace gives us. 1143 */ 1144 } 1145 1146 static netdev_features_t tun_net_fix_features(struct net_device *dev, 1147 netdev_features_t features) 1148 { 1149 struct tun_struct *tun = netdev_priv(dev); 1150 1151 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 1152 } 1153 #ifdef CONFIG_NET_POLL_CONTROLLER 1154 static void tun_poll_controller(struct net_device *dev) 1155 { 1156 /* 1157 * Tun only receives frames when: 1158 * 1) the char device endpoint gets data from user space 1159 * 2) the tun socket gets a sendmsg call from user space 1160 * If NAPI is not enabled, since both of those are synchronous 1161 * operations, we are guaranteed never to have pending data when we poll 1162 * for it so there is nothing to do here but return. 1163 * We need this though so netpoll recognizes us as an interface that 1164 * supports polling, which enables bridge devices in virt setups to 1165 * still use netconsole 1166 * If NAPI is enabled, however, we need to schedule polling for all 1167 * queues unless we are using napi_gro_frags(), which we call in 1168 * process context and not in NAPI context. 1169 */ 1170 struct tun_struct *tun = netdev_priv(dev); 1171 1172 if (tun->flags & IFF_NAPI) { 1173 struct tun_file *tfile; 1174 int i; 1175 1176 if (tun_napi_frags_enabled(tun)) 1177 return; 1178 1179 rcu_read_lock(); 1180 for (i = 0; i < tun->numqueues; i++) { 1181 tfile = rcu_dereference(tun->tfiles[i]); 1182 if (tfile->napi_enabled) 1183 napi_schedule(&tfile->napi); 1184 } 1185 rcu_read_unlock(); 1186 } 1187 return; 1188 } 1189 #endif 1190 1191 static void tun_set_headroom(struct net_device *dev, int new_hr) 1192 { 1193 struct tun_struct *tun = netdev_priv(dev); 1194 1195 if (new_hr < NET_SKB_PAD) 1196 new_hr = NET_SKB_PAD; 1197 1198 tun->align = new_hr; 1199 } 1200 1201 static void 1202 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats) 1203 { 1204 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0; 1205 struct tun_struct *tun = netdev_priv(dev); 1206 struct tun_pcpu_stats *p; 1207 int i; 1208 1209 for_each_possible_cpu(i) { 1210 u64 rxpackets, rxbytes, txpackets, txbytes; 1211 unsigned int start; 1212 1213 p = per_cpu_ptr(tun->pcpu_stats, i); 1214 do { 1215 start = u64_stats_fetch_begin(&p->syncp); 1216 rxpackets = p->rx_packets; 1217 rxbytes = p->rx_bytes; 1218 txpackets = p->tx_packets; 1219 txbytes = p->tx_bytes; 1220 } while (u64_stats_fetch_retry(&p->syncp, start)); 1221 1222 stats->rx_packets += rxpackets; 1223 stats->rx_bytes += rxbytes; 1224 stats->tx_packets += txpackets; 1225 stats->tx_bytes += txbytes; 1226 1227 /* u32 counters */ 1228 rx_dropped += p->rx_dropped; 1229 rx_frame_errors += p->rx_frame_errors; 1230 tx_dropped += p->tx_dropped; 1231 } 1232 stats->rx_dropped = rx_dropped; 1233 stats->rx_frame_errors = rx_frame_errors; 1234 stats->tx_dropped = tx_dropped; 1235 } 1236 1237 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog, 1238 struct netlink_ext_ack *extack) 1239 { 1240 struct tun_struct *tun = netdev_priv(dev); 1241 struct bpf_prog *old_prog; 1242 1243 old_prog = rtnl_dereference(tun->xdp_prog); 1244 rcu_assign_pointer(tun->xdp_prog, prog); 1245 if (old_prog) 1246 bpf_prog_put(old_prog); 1247 1248 return 0; 1249 } 1250 1251 static u32 tun_xdp_query(struct net_device *dev) 1252 { 1253 struct tun_struct *tun = netdev_priv(dev); 1254 const struct bpf_prog *xdp_prog; 1255 1256 xdp_prog = rtnl_dereference(tun->xdp_prog); 1257 if (xdp_prog) 1258 return xdp_prog->aux->id; 1259 1260 return 0; 1261 } 1262 1263 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp) 1264 { 1265 switch (xdp->command) { 1266 case XDP_SETUP_PROG: 1267 return tun_xdp_set(dev, xdp->prog, xdp->extack); 1268 case XDP_QUERY_PROG: 1269 xdp->prog_id = tun_xdp_query(dev); 1270 xdp->prog_attached = !!xdp->prog_id; 1271 return 0; 1272 default: 1273 return -EINVAL; 1274 } 1275 } 1276 1277 static const struct net_device_ops tun_netdev_ops = { 1278 .ndo_uninit = tun_net_uninit, 1279 .ndo_open = tun_net_open, 1280 .ndo_stop = tun_net_close, 1281 .ndo_start_xmit = tun_net_xmit, 1282 .ndo_fix_features = tun_net_fix_features, 1283 .ndo_select_queue = tun_select_queue, 1284 #ifdef CONFIG_NET_POLL_CONTROLLER 1285 .ndo_poll_controller = tun_poll_controller, 1286 #endif 1287 .ndo_set_rx_headroom = tun_set_headroom, 1288 .ndo_get_stats64 = tun_net_get_stats64, 1289 }; 1290 1291 static int tun_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp) 1292 { 1293 struct tun_struct *tun = netdev_priv(dev); 1294 struct xdp_buff *buff = xdp->data_hard_start; 1295 int headroom = xdp->data - xdp->data_hard_start; 1296 struct tun_file *tfile; 1297 u32 numqueues; 1298 int ret = 0; 1299 1300 /* Assure headroom is available and buff is properly aligned */ 1301 if (unlikely(headroom < sizeof(*xdp) || tun_is_xdp_buff(xdp))) 1302 return -ENOSPC; 1303 1304 *buff = *xdp; 1305 1306 rcu_read_lock(); 1307 1308 numqueues = READ_ONCE(tun->numqueues); 1309 if (!numqueues) { 1310 ret = -ENOSPC; 1311 goto out; 1312 } 1313 1314 tfile = rcu_dereference(tun->tfiles[smp_processor_id() % 1315 numqueues]); 1316 /* Encode the XDP flag into lowest bit for consumer to differ 1317 * XDP buffer from sk_buff. 1318 */ 1319 if (ptr_ring_produce(&tfile->tx_ring, tun_xdp_to_ptr(buff))) { 1320 this_cpu_inc(tun->pcpu_stats->tx_dropped); 1321 ret = -ENOSPC; 1322 } 1323 1324 out: 1325 rcu_read_unlock(); 1326 return ret; 1327 } 1328 1329 static void tun_xdp_flush(struct net_device *dev) 1330 { 1331 struct tun_struct *tun = netdev_priv(dev); 1332 struct tun_file *tfile; 1333 u32 numqueues; 1334 1335 rcu_read_lock(); 1336 1337 numqueues = READ_ONCE(tun->numqueues); 1338 if (!numqueues) 1339 goto out; 1340 1341 tfile = rcu_dereference(tun->tfiles[smp_processor_id() % 1342 numqueues]); 1343 /* Notify and wake up reader process */ 1344 if (tfile->flags & TUN_FASYNC) 1345 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 1346 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 1347 1348 out: 1349 rcu_read_unlock(); 1350 } 1351 1352 static const struct net_device_ops tap_netdev_ops = { 1353 .ndo_uninit = tun_net_uninit, 1354 .ndo_open = tun_net_open, 1355 .ndo_stop = tun_net_close, 1356 .ndo_start_xmit = tun_net_xmit, 1357 .ndo_fix_features = tun_net_fix_features, 1358 .ndo_set_rx_mode = tun_net_mclist, 1359 .ndo_set_mac_address = eth_mac_addr, 1360 .ndo_validate_addr = eth_validate_addr, 1361 .ndo_select_queue = tun_select_queue, 1362 #ifdef CONFIG_NET_POLL_CONTROLLER 1363 .ndo_poll_controller = tun_poll_controller, 1364 #endif 1365 .ndo_features_check = passthru_features_check, 1366 .ndo_set_rx_headroom = tun_set_headroom, 1367 .ndo_get_stats64 = tun_net_get_stats64, 1368 .ndo_bpf = tun_xdp, 1369 .ndo_xdp_xmit = tun_xdp_xmit, 1370 .ndo_xdp_flush = tun_xdp_flush, 1371 }; 1372 1373 static void tun_flow_init(struct tun_struct *tun) 1374 { 1375 int i; 1376 1377 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 1378 INIT_HLIST_HEAD(&tun->flows[i]); 1379 1380 tun->ageing_time = TUN_FLOW_EXPIRE; 1381 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0); 1382 mod_timer(&tun->flow_gc_timer, 1383 round_jiffies_up(jiffies + tun->ageing_time)); 1384 } 1385 1386 static void tun_flow_uninit(struct tun_struct *tun) 1387 { 1388 del_timer_sync(&tun->flow_gc_timer); 1389 tun_flow_flush(tun); 1390 } 1391 1392 #define MIN_MTU 68 1393 #define MAX_MTU 65535 1394 1395 /* Initialize net device. */ 1396 static void tun_net_init(struct net_device *dev) 1397 { 1398 struct tun_struct *tun = netdev_priv(dev); 1399 1400 switch (tun->flags & TUN_TYPE_MASK) { 1401 case IFF_TUN: 1402 dev->netdev_ops = &tun_netdev_ops; 1403 1404 /* Point-to-Point TUN Device */ 1405 dev->hard_header_len = 0; 1406 dev->addr_len = 0; 1407 dev->mtu = 1500; 1408 1409 /* Zero header length */ 1410 dev->type = ARPHRD_NONE; 1411 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 1412 break; 1413 1414 case IFF_TAP: 1415 dev->netdev_ops = &tap_netdev_ops; 1416 /* Ethernet TAP Device */ 1417 ether_setup(dev); 1418 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 1419 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 1420 1421 eth_hw_addr_random(dev); 1422 1423 break; 1424 } 1425 1426 dev->min_mtu = MIN_MTU; 1427 dev->max_mtu = MAX_MTU - dev->hard_header_len; 1428 } 1429 1430 /* Character device part */ 1431 1432 /* Poll */ 1433 static __poll_t tun_chr_poll(struct file *file, poll_table *wait) 1434 { 1435 struct tun_file *tfile = file->private_data; 1436 struct tun_struct *tun = tun_get(tfile); 1437 struct sock *sk; 1438 __poll_t mask = 0; 1439 1440 if (!tun) 1441 return EPOLLERR; 1442 1443 sk = tfile->socket.sk; 1444 1445 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 1446 1447 poll_wait(file, sk_sleep(sk), wait); 1448 1449 if (!ptr_ring_empty(&tfile->tx_ring)) 1450 mask |= EPOLLIN | EPOLLRDNORM; 1451 1452 if (tun->dev->flags & IFF_UP && 1453 (sock_writeable(sk) || 1454 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) && 1455 sock_writeable(sk)))) 1456 mask |= EPOLLOUT | EPOLLWRNORM; 1457 1458 if (tun->dev->reg_state != NETREG_REGISTERED) 1459 mask = EPOLLERR; 1460 1461 tun_put(tun); 1462 return mask; 1463 } 1464 1465 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile, 1466 size_t len, 1467 const struct iov_iter *it) 1468 { 1469 struct sk_buff *skb; 1470 size_t linear; 1471 int err; 1472 int i; 1473 1474 if (it->nr_segs > MAX_SKB_FRAGS + 1) 1475 return ERR_PTR(-ENOMEM); 1476 1477 local_bh_disable(); 1478 skb = napi_get_frags(&tfile->napi); 1479 local_bh_enable(); 1480 if (!skb) 1481 return ERR_PTR(-ENOMEM); 1482 1483 linear = iov_iter_single_seg_count(it); 1484 err = __skb_grow(skb, linear); 1485 if (err) 1486 goto free; 1487 1488 skb->len = len; 1489 skb->data_len = len - linear; 1490 skb->truesize += skb->data_len; 1491 1492 for (i = 1; i < it->nr_segs; i++) { 1493 struct page_frag *pfrag = ¤t->task_frag; 1494 size_t fragsz = it->iov[i].iov_len; 1495 1496 if (fragsz == 0 || fragsz > PAGE_SIZE) { 1497 err = -EINVAL; 1498 goto free; 1499 } 1500 1501 if (!skb_page_frag_refill(fragsz, pfrag, GFP_KERNEL)) { 1502 err = -ENOMEM; 1503 goto free; 1504 } 1505 1506 skb_fill_page_desc(skb, i - 1, pfrag->page, 1507 pfrag->offset, fragsz); 1508 page_ref_inc(pfrag->page); 1509 pfrag->offset += fragsz; 1510 } 1511 1512 return skb; 1513 free: 1514 /* frees skb and all frags allocated with napi_alloc_frag() */ 1515 napi_free_frags(&tfile->napi); 1516 return ERR_PTR(err); 1517 } 1518 1519 /* prepad is the amount to reserve at front. len is length after that. 1520 * linear is a hint as to how much to copy (usually headers). */ 1521 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 1522 size_t prepad, size_t len, 1523 size_t linear, int noblock) 1524 { 1525 struct sock *sk = tfile->socket.sk; 1526 struct sk_buff *skb; 1527 int err; 1528 1529 /* Under a page? Don't bother with paged skb. */ 1530 if (prepad + len < PAGE_SIZE || !linear) 1531 linear = len; 1532 1533 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 1534 &err, 0); 1535 if (!skb) 1536 return ERR_PTR(err); 1537 1538 skb_reserve(skb, prepad); 1539 skb_put(skb, linear); 1540 skb->data_len = len - linear; 1541 skb->len += len - linear; 1542 1543 return skb; 1544 } 1545 1546 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile, 1547 struct sk_buff *skb, int more) 1548 { 1549 struct sk_buff_head *queue = &tfile->sk.sk_write_queue; 1550 struct sk_buff_head process_queue; 1551 u32 rx_batched = tun->rx_batched; 1552 bool rcv = false; 1553 1554 if (!rx_batched || (!more && skb_queue_empty(queue))) { 1555 local_bh_disable(); 1556 netif_receive_skb(skb); 1557 local_bh_enable(); 1558 return; 1559 } 1560 1561 spin_lock(&queue->lock); 1562 if (!more || skb_queue_len(queue) == rx_batched) { 1563 __skb_queue_head_init(&process_queue); 1564 skb_queue_splice_tail_init(queue, &process_queue); 1565 rcv = true; 1566 } else { 1567 __skb_queue_tail(queue, skb); 1568 } 1569 spin_unlock(&queue->lock); 1570 1571 if (rcv) { 1572 struct sk_buff *nskb; 1573 1574 local_bh_disable(); 1575 while ((nskb = __skb_dequeue(&process_queue))) 1576 netif_receive_skb(nskb); 1577 netif_receive_skb(skb); 1578 local_bh_enable(); 1579 } 1580 } 1581 1582 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile, 1583 int len, int noblock, bool zerocopy) 1584 { 1585 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 1586 return false; 1587 1588 if (tfile->socket.sk->sk_sndbuf != INT_MAX) 1589 return false; 1590 1591 if (!noblock) 1592 return false; 1593 1594 if (zerocopy) 1595 return false; 1596 1597 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) + 1598 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE) 1599 return false; 1600 1601 return true; 1602 } 1603 1604 static struct sk_buff *tun_build_skb(struct tun_struct *tun, 1605 struct tun_file *tfile, 1606 struct iov_iter *from, 1607 struct virtio_net_hdr *hdr, 1608 int len, int *skb_xdp) 1609 { 1610 struct page_frag *alloc_frag = ¤t->task_frag; 1611 struct sk_buff *skb; 1612 struct bpf_prog *xdp_prog; 1613 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 1614 unsigned int delta = 0; 1615 char *buf; 1616 size_t copied; 1617 bool xdp_xmit = false; 1618 int err, pad = TUN_RX_PAD; 1619 1620 rcu_read_lock(); 1621 xdp_prog = rcu_dereference(tun->xdp_prog); 1622 if (xdp_prog) 1623 pad += TUN_HEADROOM; 1624 buflen += SKB_DATA_ALIGN(len + pad); 1625 rcu_read_unlock(); 1626 1627 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES); 1628 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL))) 1629 return ERR_PTR(-ENOMEM); 1630 1631 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset; 1632 copied = copy_page_from_iter(alloc_frag->page, 1633 alloc_frag->offset + pad, 1634 len, from); 1635 if (copied != len) 1636 return ERR_PTR(-EFAULT); 1637 1638 /* There's a small window that XDP may be set after the check 1639 * of xdp_prog above, this should be rare and for simplicity 1640 * we do XDP on skb in case the headroom is not enough. 1641 */ 1642 if (hdr->gso_type || !xdp_prog) 1643 *skb_xdp = 1; 1644 else 1645 *skb_xdp = 0; 1646 1647 rcu_read_lock(); 1648 xdp_prog = rcu_dereference(tun->xdp_prog); 1649 if (xdp_prog && !*skb_xdp) { 1650 struct xdp_buff xdp; 1651 void *orig_data; 1652 u32 act; 1653 1654 xdp.data_hard_start = buf; 1655 xdp.data = buf + pad; 1656 xdp_set_data_meta_invalid(&xdp); 1657 xdp.data_end = xdp.data + len; 1658 xdp.rxq = &tfile->xdp_rxq; 1659 orig_data = xdp.data; 1660 act = bpf_prog_run_xdp(xdp_prog, &xdp); 1661 1662 switch (act) { 1663 case XDP_REDIRECT: 1664 get_page(alloc_frag->page); 1665 alloc_frag->offset += buflen; 1666 ++tfile->xdp_pending_pkts; 1667 err = xdp_do_redirect(tun->dev, &xdp, xdp_prog); 1668 if (err) 1669 goto err_redirect; 1670 rcu_read_unlock(); 1671 return NULL; 1672 case XDP_TX: 1673 xdp_xmit = true; 1674 /* fall through */ 1675 case XDP_PASS: 1676 delta = orig_data - xdp.data; 1677 break; 1678 default: 1679 bpf_warn_invalid_xdp_action(act); 1680 /* fall through */ 1681 case XDP_ABORTED: 1682 trace_xdp_exception(tun->dev, xdp_prog, act); 1683 /* fall through */ 1684 case XDP_DROP: 1685 goto err_xdp; 1686 } 1687 } 1688 1689 skb = build_skb(buf, buflen); 1690 if (!skb) { 1691 rcu_read_unlock(); 1692 return ERR_PTR(-ENOMEM); 1693 } 1694 1695 skb_reserve(skb, pad - delta); 1696 skb_put(skb, len + delta); 1697 get_page(alloc_frag->page); 1698 alloc_frag->offset += buflen; 1699 1700 if (xdp_xmit) { 1701 skb->dev = tun->dev; 1702 generic_xdp_tx(skb, xdp_prog); 1703 rcu_read_unlock(); 1704 return NULL; 1705 } 1706 1707 rcu_read_unlock(); 1708 1709 return skb; 1710 1711 err_redirect: 1712 put_page(alloc_frag->page); 1713 err_xdp: 1714 rcu_read_unlock(); 1715 this_cpu_inc(tun->pcpu_stats->rx_dropped); 1716 return NULL; 1717 } 1718 1719 /* Get packet from user space buffer */ 1720 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1721 void *msg_control, struct iov_iter *from, 1722 int noblock, bool more) 1723 { 1724 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1725 struct sk_buff *skb; 1726 size_t total_len = iov_iter_count(from); 1727 size_t len = total_len, align = tun->align, linear; 1728 struct virtio_net_hdr gso = { 0 }; 1729 struct tun_pcpu_stats *stats; 1730 int good_linear; 1731 int copylen; 1732 bool zerocopy = false; 1733 int err; 1734 u32 rxhash = 0; 1735 int skb_xdp = 1; 1736 bool frags = tun_napi_frags_enabled(tun); 1737 1738 if (!(tun->dev->flags & IFF_UP)) 1739 return -EIO; 1740 1741 if (!(tun->flags & IFF_NO_PI)) { 1742 if (len < sizeof(pi)) 1743 return -EINVAL; 1744 len -= sizeof(pi); 1745 1746 if (!copy_from_iter_full(&pi, sizeof(pi), from)) 1747 return -EFAULT; 1748 } 1749 1750 if (tun->flags & IFF_VNET_HDR) { 1751 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz); 1752 1753 if (len < vnet_hdr_sz) 1754 return -EINVAL; 1755 len -= vnet_hdr_sz; 1756 1757 if (!copy_from_iter_full(&gso, sizeof(gso), from)) 1758 return -EFAULT; 1759 1760 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1761 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len)) 1762 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2); 1763 1764 if (tun16_to_cpu(tun, gso.hdr_len) > len) 1765 return -EINVAL; 1766 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso)); 1767 } 1768 1769 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) { 1770 align += NET_IP_ALIGN; 1771 if (unlikely(len < ETH_HLEN || 1772 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN))) 1773 return -EINVAL; 1774 } 1775 1776 good_linear = SKB_MAX_HEAD(align); 1777 1778 if (msg_control) { 1779 struct iov_iter i = *from; 1780 1781 /* There are 256 bytes to be copied in skb, so there is 1782 * enough room for skb expand head in case it is used. 1783 * The rest of the buffer is mapped from userspace. 1784 */ 1785 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN; 1786 if (copylen > good_linear) 1787 copylen = good_linear; 1788 linear = copylen; 1789 iov_iter_advance(&i, copylen); 1790 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS) 1791 zerocopy = true; 1792 } 1793 1794 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) { 1795 /* For the packet that is not easy to be processed 1796 * (e.g gso or jumbo packet), we will do it at after 1797 * skb was created with generic XDP routine. 1798 */ 1799 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp); 1800 if (IS_ERR(skb)) { 1801 this_cpu_inc(tun->pcpu_stats->rx_dropped); 1802 return PTR_ERR(skb); 1803 } 1804 if (!skb) 1805 return total_len; 1806 } else { 1807 if (!zerocopy) { 1808 copylen = len; 1809 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear) 1810 linear = good_linear; 1811 else 1812 linear = tun16_to_cpu(tun, gso.hdr_len); 1813 } 1814 1815 if (frags) { 1816 mutex_lock(&tfile->napi_mutex); 1817 skb = tun_napi_alloc_frags(tfile, copylen, from); 1818 /* tun_napi_alloc_frags() enforces a layout for the skb. 1819 * If zerocopy is enabled, then this layout will be 1820 * overwritten by zerocopy_sg_from_iter(). 1821 */ 1822 zerocopy = false; 1823 } else { 1824 skb = tun_alloc_skb(tfile, align, copylen, linear, 1825 noblock); 1826 } 1827 1828 if (IS_ERR(skb)) { 1829 if (PTR_ERR(skb) != -EAGAIN) 1830 this_cpu_inc(tun->pcpu_stats->rx_dropped); 1831 if (frags) 1832 mutex_unlock(&tfile->napi_mutex); 1833 return PTR_ERR(skb); 1834 } 1835 1836 if (zerocopy) 1837 err = zerocopy_sg_from_iter(skb, from); 1838 else 1839 err = skb_copy_datagram_from_iter(skb, 0, from, len); 1840 1841 if (err) { 1842 this_cpu_inc(tun->pcpu_stats->rx_dropped); 1843 kfree_skb(skb); 1844 if (frags) { 1845 tfile->napi.skb = NULL; 1846 mutex_unlock(&tfile->napi_mutex); 1847 } 1848 1849 return -EFAULT; 1850 } 1851 } 1852 1853 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) { 1854 this_cpu_inc(tun->pcpu_stats->rx_frame_errors); 1855 kfree_skb(skb); 1856 if (frags) { 1857 tfile->napi.skb = NULL; 1858 mutex_unlock(&tfile->napi_mutex); 1859 } 1860 1861 return -EINVAL; 1862 } 1863 1864 switch (tun->flags & TUN_TYPE_MASK) { 1865 case IFF_TUN: 1866 if (tun->flags & IFF_NO_PI) { 1867 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0; 1868 1869 switch (ip_version) { 1870 case 4: 1871 pi.proto = htons(ETH_P_IP); 1872 break; 1873 case 6: 1874 pi.proto = htons(ETH_P_IPV6); 1875 break; 1876 default: 1877 this_cpu_inc(tun->pcpu_stats->rx_dropped); 1878 kfree_skb(skb); 1879 return -EINVAL; 1880 } 1881 } 1882 1883 skb_reset_mac_header(skb); 1884 skb->protocol = pi.proto; 1885 skb->dev = tun->dev; 1886 break; 1887 case IFF_TAP: 1888 if (!frags) 1889 skb->protocol = eth_type_trans(skb, tun->dev); 1890 break; 1891 } 1892 1893 /* copy skb_ubuf_info for callback when skb has no error */ 1894 if (zerocopy) { 1895 skb_shinfo(skb)->destructor_arg = msg_control; 1896 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1897 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1898 } else if (msg_control) { 1899 struct ubuf_info *uarg = msg_control; 1900 uarg->callback(uarg, false); 1901 } 1902 1903 skb_reset_network_header(skb); 1904 skb_probe_transport_header(skb, 0); 1905 1906 if (skb_xdp) { 1907 struct bpf_prog *xdp_prog; 1908 int ret; 1909 1910 rcu_read_lock(); 1911 xdp_prog = rcu_dereference(tun->xdp_prog); 1912 if (xdp_prog) { 1913 ret = do_xdp_generic(xdp_prog, skb); 1914 if (ret != XDP_PASS) { 1915 rcu_read_unlock(); 1916 return total_len; 1917 } 1918 } 1919 rcu_read_unlock(); 1920 } 1921 1922 rcu_read_lock(); 1923 if (!rcu_dereference(tun->steering_prog)) 1924 rxhash = __skb_get_hash_symmetric(skb); 1925 rcu_read_unlock(); 1926 1927 if (frags) { 1928 /* Exercise flow dissector code path. */ 1929 u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb)); 1930 1931 if (unlikely(headlen > skb_headlen(skb))) { 1932 this_cpu_inc(tun->pcpu_stats->rx_dropped); 1933 napi_free_frags(&tfile->napi); 1934 mutex_unlock(&tfile->napi_mutex); 1935 WARN_ON(1); 1936 return -ENOMEM; 1937 } 1938 1939 local_bh_disable(); 1940 napi_gro_frags(&tfile->napi); 1941 local_bh_enable(); 1942 mutex_unlock(&tfile->napi_mutex); 1943 } else if (tfile->napi_enabled) { 1944 struct sk_buff_head *queue = &tfile->sk.sk_write_queue; 1945 int queue_len; 1946 1947 spin_lock_bh(&queue->lock); 1948 __skb_queue_tail(queue, skb); 1949 queue_len = skb_queue_len(queue); 1950 spin_unlock(&queue->lock); 1951 1952 if (!more || queue_len > NAPI_POLL_WEIGHT) 1953 napi_schedule(&tfile->napi); 1954 1955 local_bh_enable(); 1956 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) { 1957 tun_rx_batched(tun, tfile, skb, more); 1958 } else { 1959 netif_rx_ni(skb); 1960 } 1961 1962 stats = get_cpu_ptr(tun->pcpu_stats); 1963 u64_stats_update_begin(&stats->syncp); 1964 stats->rx_packets++; 1965 stats->rx_bytes += len; 1966 u64_stats_update_end(&stats->syncp); 1967 put_cpu_ptr(stats); 1968 1969 if (rxhash) 1970 tun_flow_update(tun, rxhash, tfile); 1971 1972 return total_len; 1973 } 1974 1975 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from) 1976 { 1977 struct file *file = iocb->ki_filp; 1978 struct tun_file *tfile = file->private_data; 1979 struct tun_struct *tun = tun_get(tfile); 1980 ssize_t result; 1981 1982 if (!tun) 1983 return -EBADFD; 1984 1985 result = tun_get_user(tun, tfile, NULL, from, 1986 file->f_flags & O_NONBLOCK, false); 1987 1988 if (tfile->xdp_pending_pkts) { 1989 tfile->xdp_pending_pkts = 0; 1990 xdp_do_flush_map(); 1991 } 1992 1993 tun_put(tun); 1994 return result; 1995 } 1996 1997 static ssize_t tun_put_user_xdp(struct tun_struct *tun, 1998 struct tun_file *tfile, 1999 struct xdp_buff *xdp, 2000 struct iov_iter *iter) 2001 { 2002 int vnet_hdr_sz = 0; 2003 size_t size = xdp->data_end - xdp->data; 2004 struct tun_pcpu_stats *stats; 2005 size_t ret; 2006 2007 if (tun->flags & IFF_VNET_HDR) { 2008 struct virtio_net_hdr gso = { 0 }; 2009 2010 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz); 2011 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz)) 2012 return -EINVAL; 2013 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) != 2014 sizeof(gso))) 2015 return -EFAULT; 2016 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso)); 2017 } 2018 2019 ret = copy_to_iter(xdp->data, size, iter) + vnet_hdr_sz; 2020 2021 stats = get_cpu_ptr(tun->pcpu_stats); 2022 u64_stats_update_begin(&stats->syncp); 2023 stats->tx_packets++; 2024 stats->tx_bytes += ret; 2025 u64_stats_update_end(&stats->syncp); 2026 put_cpu_ptr(tun->pcpu_stats); 2027 2028 return ret; 2029 } 2030 2031 /* Put packet to the user space buffer */ 2032 static ssize_t tun_put_user(struct tun_struct *tun, 2033 struct tun_file *tfile, 2034 struct sk_buff *skb, 2035 struct iov_iter *iter) 2036 { 2037 struct tun_pi pi = { 0, skb->protocol }; 2038 struct tun_pcpu_stats *stats; 2039 ssize_t total; 2040 int vlan_offset = 0; 2041 int vlan_hlen = 0; 2042 int vnet_hdr_sz = 0; 2043 2044 if (skb_vlan_tag_present(skb)) 2045 vlan_hlen = VLAN_HLEN; 2046 2047 if (tun->flags & IFF_VNET_HDR) 2048 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz); 2049 2050 total = skb->len + vlan_hlen + vnet_hdr_sz; 2051 2052 if (!(tun->flags & IFF_NO_PI)) { 2053 if (iov_iter_count(iter) < sizeof(pi)) 2054 return -EINVAL; 2055 2056 total += sizeof(pi); 2057 if (iov_iter_count(iter) < total) { 2058 /* Packet will be striped */ 2059 pi.flags |= TUN_PKT_STRIP; 2060 } 2061 2062 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi)) 2063 return -EFAULT; 2064 } 2065 2066 if (vnet_hdr_sz) { 2067 struct virtio_net_hdr gso; 2068 2069 if (iov_iter_count(iter) < vnet_hdr_sz) 2070 return -EINVAL; 2071 2072 if (virtio_net_hdr_from_skb(skb, &gso, 2073 tun_is_little_endian(tun), true)) { 2074 struct skb_shared_info *sinfo = skb_shinfo(skb); 2075 pr_err("unexpected GSO type: " 2076 "0x%x, gso_size %d, hdr_len %d\n", 2077 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size), 2078 tun16_to_cpu(tun, gso.hdr_len)); 2079 print_hex_dump(KERN_ERR, "tun: ", 2080 DUMP_PREFIX_NONE, 2081 16, 1, skb->head, 2082 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true); 2083 WARN_ON_ONCE(1); 2084 return -EINVAL; 2085 } 2086 2087 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso)) 2088 return -EFAULT; 2089 2090 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso)); 2091 } 2092 2093 if (vlan_hlen) { 2094 int ret; 2095 struct veth veth; 2096 2097 veth.h_vlan_proto = skb->vlan_proto; 2098 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb)); 2099 2100 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 2101 2102 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset); 2103 if (ret || !iov_iter_count(iter)) 2104 goto done; 2105 2106 ret = copy_to_iter(&veth, sizeof(veth), iter); 2107 if (ret != sizeof(veth) || !iov_iter_count(iter)) 2108 goto done; 2109 } 2110 2111 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset); 2112 2113 done: 2114 /* caller is in process context, */ 2115 stats = get_cpu_ptr(tun->pcpu_stats); 2116 u64_stats_update_begin(&stats->syncp); 2117 stats->tx_packets++; 2118 stats->tx_bytes += skb->len + vlan_hlen; 2119 u64_stats_update_end(&stats->syncp); 2120 put_cpu_ptr(tun->pcpu_stats); 2121 2122 return total; 2123 } 2124 2125 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err) 2126 { 2127 DECLARE_WAITQUEUE(wait, current); 2128 void *ptr = NULL; 2129 int error = 0; 2130 2131 ptr = ptr_ring_consume(&tfile->tx_ring); 2132 if (ptr) 2133 goto out; 2134 if (noblock) { 2135 error = -EAGAIN; 2136 goto out; 2137 } 2138 2139 add_wait_queue(&tfile->wq.wait, &wait); 2140 current->state = TASK_INTERRUPTIBLE; 2141 2142 while (1) { 2143 ptr = ptr_ring_consume(&tfile->tx_ring); 2144 if (ptr) 2145 break; 2146 if (signal_pending(current)) { 2147 error = -ERESTARTSYS; 2148 break; 2149 } 2150 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) { 2151 error = -EFAULT; 2152 break; 2153 } 2154 2155 schedule(); 2156 } 2157 2158 current->state = TASK_RUNNING; 2159 remove_wait_queue(&tfile->wq.wait, &wait); 2160 2161 out: 2162 *err = error; 2163 return ptr; 2164 } 2165 2166 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 2167 struct iov_iter *to, 2168 int noblock, void *ptr) 2169 { 2170 ssize_t ret; 2171 int err; 2172 2173 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 2174 2175 if (!iov_iter_count(to)) { 2176 tun_ptr_free(ptr); 2177 return 0; 2178 } 2179 2180 if (!ptr) { 2181 /* Read frames from ring */ 2182 ptr = tun_ring_recv(tfile, noblock, &err); 2183 if (!ptr) 2184 return err; 2185 } 2186 2187 if (tun_is_xdp_buff(ptr)) { 2188 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr); 2189 2190 ret = tun_put_user_xdp(tun, tfile, xdp, to); 2191 put_page(virt_to_head_page(xdp->data)); 2192 } else { 2193 struct sk_buff *skb = ptr; 2194 2195 ret = tun_put_user(tun, tfile, skb, to); 2196 if (unlikely(ret < 0)) 2197 kfree_skb(skb); 2198 else 2199 consume_skb(skb); 2200 } 2201 2202 return ret; 2203 } 2204 2205 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 2206 { 2207 struct file *file = iocb->ki_filp; 2208 struct tun_file *tfile = file->private_data; 2209 struct tun_struct *tun = tun_get(tfile); 2210 ssize_t len = iov_iter_count(to), ret; 2211 2212 if (!tun) 2213 return -EBADFD; 2214 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL); 2215 ret = min_t(ssize_t, ret, len); 2216 if (ret > 0) 2217 iocb->ki_pos = ret; 2218 tun_put(tun); 2219 return ret; 2220 } 2221 2222 static void tun_prog_free(struct rcu_head *rcu) 2223 { 2224 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu); 2225 2226 bpf_prog_destroy(prog->prog); 2227 kfree(prog); 2228 } 2229 2230 static int __tun_set_ebpf(struct tun_struct *tun, 2231 struct tun_prog __rcu **prog_p, 2232 struct bpf_prog *prog) 2233 { 2234 struct tun_prog *old, *new = NULL; 2235 2236 if (prog) { 2237 new = kmalloc(sizeof(*new), GFP_KERNEL); 2238 if (!new) 2239 return -ENOMEM; 2240 new->prog = prog; 2241 } 2242 2243 spin_lock_bh(&tun->lock); 2244 old = rcu_dereference_protected(*prog_p, 2245 lockdep_is_held(&tun->lock)); 2246 rcu_assign_pointer(*prog_p, new); 2247 spin_unlock_bh(&tun->lock); 2248 2249 if (old) 2250 call_rcu(&old->rcu, tun_prog_free); 2251 2252 return 0; 2253 } 2254 2255 static void tun_free_netdev(struct net_device *dev) 2256 { 2257 struct tun_struct *tun = netdev_priv(dev); 2258 2259 BUG_ON(!(list_empty(&tun->disabled))); 2260 free_percpu(tun->pcpu_stats); 2261 tun_flow_uninit(tun); 2262 security_tun_dev_free_security(tun->security); 2263 __tun_set_ebpf(tun, &tun->steering_prog, NULL); 2264 __tun_set_ebpf(tun, &tun->filter_prog, NULL); 2265 } 2266 2267 static void tun_setup(struct net_device *dev) 2268 { 2269 struct tun_struct *tun = netdev_priv(dev); 2270 2271 tun->owner = INVALID_UID; 2272 tun->group = INVALID_GID; 2273 2274 dev->ethtool_ops = &tun_ethtool_ops; 2275 dev->needs_free_netdev = true; 2276 dev->priv_destructor = tun_free_netdev; 2277 /* We prefer our own queue length */ 2278 dev->tx_queue_len = TUN_READQ_SIZE; 2279 } 2280 2281 /* Trivial set of netlink ops to allow deleting tun or tap 2282 * device with netlink. 2283 */ 2284 static int tun_validate(struct nlattr *tb[], struct nlattr *data[], 2285 struct netlink_ext_ack *extack) 2286 { 2287 return -EINVAL; 2288 } 2289 2290 static size_t tun_get_size(const struct net_device *dev) 2291 { 2292 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t)); 2293 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t)); 2294 2295 return nla_total_size(sizeof(uid_t)) + /* OWNER */ 2296 nla_total_size(sizeof(gid_t)) + /* GROUP */ 2297 nla_total_size(sizeof(u8)) + /* TYPE */ 2298 nla_total_size(sizeof(u8)) + /* PI */ 2299 nla_total_size(sizeof(u8)) + /* VNET_HDR */ 2300 nla_total_size(sizeof(u8)) + /* PERSIST */ 2301 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */ 2302 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */ 2303 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */ 2304 0; 2305 } 2306 2307 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev) 2308 { 2309 struct tun_struct *tun = netdev_priv(dev); 2310 2311 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK)) 2312 goto nla_put_failure; 2313 if (uid_valid(tun->owner) && 2314 nla_put_u32(skb, IFLA_TUN_OWNER, 2315 from_kuid_munged(current_user_ns(), tun->owner))) 2316 goto nla_put_failure; 2317 if (gid_valid(tun->group) && 2318 nla_put_u32(skb, IFLA_TUN_GROUP, 2319 from_kgid_munged(current_user_ns(), tun->group))) 2320 goto nla_put_failure; 2321 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI))) 2322 goto nla_put_failure; 2323 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR))) 2324 goto nla_put_failure; 2325 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST))) 2326 goto nla_put_failure; 2327 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE, 2328 !!(tun->flags & IFF_MULTI_QUEUE))) 2329 goto nla_put_failure; 2330 if (tun->flags & IFF_MULTI_QUEUE) { 2331 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues)) 2332 goto nla_put_failure; 2333 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES, 2334 tun->numdisabled)) 2335 goto nla_put_failure; 2336 } 2337 2338 return 0; 2339 2340 nla_put_failure: 2341 return -EMSGSIZE; 2342 } 2343 2344 static struct rtnl_link_ops tun_link_ops __read_mostly = { 2345 .kind = DRV_NAME, 2346 .priv_size = sizeof(struct tun_struct), 2347 .setup = tun_setup, 2348 .validate = tun_validate, 2349 .get_size = tun_get_size, 2350 .fill_info = tun_fill_info, 2351 }; 2352 2353 static void tun_sock_write_space(struct sock *sk) 2354 { 2355 struct tun_file *tfile; 2356 wait_queue_head_t *wqueue; 2357 2358 if (!sock_writeable(sk)) 2359 return; 2360 2361 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags)) 2362 return; 2363 2364 wqueue = sk_sleep(sk); 2365 if (wqueue && waitqueue_active(wqueue)) 2366 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT | 2367 EPOLLWRNORM | EPOLLWRBAND); 2368 2369 tfile = container_of(sk, struct tun_file, sk); 2370 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 2371 } 2372 2373 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) 2374 { 2375 int ret; 2376 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 2377 struct tun_struct *tun = tun_get(tfile); 2378 2379 if (!tun) 2380 return -EBADFD; 2381 2382 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter, 2383 m->msg_flags & MSG_DONTWAIT, 2384 m->msg_flags & MSG_MORE); 2385 2386 if (tfile->xdp_pending_pkts >= NAPI_POLL_WEIGHT || 2387 !(m->msg_flags & MSG_MORE)) { 2388 tfile->xdp_pending_pkts = 0; 2389 xdp_do_flush_map(); 2390 } 2391 2392 tun_put(tun); 2393 return ret; 2394 } 2395 2396 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, 2397 int flags) 2398 { 2399 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 2400 struct tun_struct *tun = tun_get(tfile); 2401 void *ptr = m->msg_control; 2402 int ret; 2403 2404 if (!tun) { 2405 ret = -EBADFD; 2406 goto out_free; 2407 } 2408 2409 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 2410 ret = -EINVAL; 2411 goto out_put_tun; 2412 } 2413 if (flags & MSG_ERRQUEUE) { 2414 ret = sock_recv_errqueue(sock->sk, m, total_len, 2415 SOL_PACKET, TUN_TX_TIMESTAMP); 2416 goto out; 2417 } 2418 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr); 2419 if (ret > (ssize_t)total_len) { 2420 m->msg_flags |= MSG_TRUNC; 2421 ret = flags & MSG_TRUNC ? ret : total_len; 2422 } 2423 out: 2424 tun_put(tun); 2425 return ret; 2426 2427 out_put_tun: 2428 tun_put(tun); 2429 out_free: 2430 tun_ptr_free(ptr); 2431 return ret; 2432 } 2433 2434 static int tun_ptr_peek_len(void *ptr) 2435 { 2436 if (likely(ptr)) { 2437 if (tun_is_xdp_buff(ptr)) { 2438 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr); 2439 2440 return xdp->data_end - xdp->data; 2441 } 2442 return __skb_array_len_with_tag(ptr); 2443 } else { 2444 return 0; 2445 } 2446 } 2447 2448 static int tun_peek_len(struct socket *sock) 2449 { 2450 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 2451 struct tun_struct *tun; 2452 int ret = 0; 2453 2454 tun = tun_get(tfile); 2455 if (!tun) 2456 return 0; 2457 2458 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len); 2459 tun_put(tun); 2460 2461 return ret; 2462 } 2463 2464 /* Ops structure to mimic raw sockets with tun */ 2465 static const struct proto_ops tun_socket_ops = { 2466 .peek_len = tun_peek_len, 2467 .sendmsg = tun_sendmsg, 2468 .recvmsg = tun_recvmsg, 2469 }; 2470 2471 static struct proto tun_proto = { 2472 .name = "tun", 2473 .owner = THIS_MODULE, 2474 .obj_size = sizeof(struct tun_file), 2475 }; 2476 2477 static int tun_flags(struct tun_struct *tun) 2478 { 2479 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP); 2480 } 2481 2482 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 2483 char *buf) 2484 { 2485 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 2486 return sprintf(buf, "0x%x\n", tun_flags(tun)); 2487 } 2488 2489 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 2490 char *buf) 2491 { 2492 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 2493 return uid_valid(tun->owner)? 2494 sprintf(buf, "%u\n", 2495 from_kuid_munged(current_user_ns(), tun->owner)): 2496 sprintf(buf, "-1\n"); 2497 } 2498 2499 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 2500 char *buf) 2501 { 2502 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 2503 return gid_valid(tun->group) ? 2504 sprintf(buf, "%u\n", 2505 from_kgid_munged(current_user_ns(), tun->group)): 2506 sprintf(buf, "-1\n"); 2507 } 2508 2509 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 2510 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 2511 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 2512 2513 static struct attribute *tun_dev_attrs[] = { 2514 &dev_attr_tun_flags.attr, 2515 &dev_attr_owner.attr, 2516 &dev_attr_group.attr, 2517 NULL 2518 }; 2519 2520 static const struct attribute_group tun_attr_group = { 2521 .attrs = tun_dev_attrs 2522 }; 2523 2524 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 2525 { 2526 struct tun_struct *tun; 2527 struct tun_file *tfile = file->private_data; 2528 struct net_device *dev; 2529 int err; 2530 2531 if (tfile->detached) 2532 return -EINVAL; 2533 2534 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) { 2535 if (!capable(CAP_NET_ADMIN)) 2536 return -EPERM; 2537 2538 if (!(ifr->ifr_flags & IFF_NAPI) || 2539 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP) 2540 return -EINVAL; 2541 } 2542 2543 dev = __dev_get_by_name(net, ifr->ifr_name); 2544 if (dev) { 2545 if (ifr->ifr_flags & IFF_TUN_EXCL) 2546 return -EBUSY; 2547 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 2548 tun = netdev_priv(dev); 2549 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 2550 tun = netdev_priv(dev); 2551 else 2552 return -EINVAL; 2553 2554 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 2555 !!(tun->flags & IFF_MULTI_QUEUE)) 2556 return -EINVAL; 2557 2558 if (tun_not_capable(tun)) 2559 return -EPERM; 2560 err = security_tun_dev_open(tun->security); 2561 if (err < 0) 2562 return err; 2563 2564 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER, 2565 ifr->ifr_flags & IFF_NAPI); 2566 if (err < 0) 2567 return err; 2568 2569 if (tun->flags & IFF_MULTI_QUEUE && 2570 (tun->numqueues + tun->numdisabled > 1)) { 2571 /* One or more queue has already been attached, no need 2572 * to initialize the device again. 2573 */ 2574 return 0; 2575 } 2576 } 2577 else { 2578 char *name; 2579 unsigned long flags = 0; 2580 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 2581 MAX_TAP_QUEUES : 1; 2582 2583 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 2584 return -EPERM; 2585 err = security_tun_dev_create(); 2586 if (err < 0) 2587 return err; 2588 2589 /* Set dev type */ 2590 if (ifr->ifr_flags & IFF_TUN) { 2591 /* TUN device */ 2592 flags |= IFF_TUN; 2593 name = "tun%d"; 2594 } else if (ifr->ifr_flags & IFF_TAP) { 2595 /* TAP device */ 2596 flags |= IFF_TAP; 2597 name = "tap%d"; 2598 } else 2599 return -EINVAL; 2600 2601 if (*ifr->ifr_name) 2602 name = ifr->ifr_name; 2603 2604 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 2605 NET_NAME_UNKNOWN, tun_setup, queues, 2606 queues); 2607 2608 if (!dev) 2609 return -ENOMEM; 2610 err = dev_get_valid_name(net, dev, name); 2611 if (err < 0) 2612 goto err_free_dev; 2613 2614 dev_net_set(dev, net); 2615 dev->rtnl_link_ops = &tun_link_ops; 2616 dev->ifindex = tfile->ifindex; 2617 dev->sysfs_groups[0] = &tun_attr_group; 2618 2619 tun = netdev_priv(dev); 2620 tun->dev = dev; 2621 tun->flags = flags; 2622 tun->txflt.count = 0; 2623 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 2624 2625 tun->align = NET_SKB_PAD; 2626 tun->filter_attached = false; 2627 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 2628 tun->rx_batched = 0; 2629 RCU_INIT_POINTER(tun->steering_prog, NULL); 2630 2631 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats); 2632 if (!tun->pcpu_stats) { 2633 err = -ENOMEM; 2634 goto err_free_dev; 2635 } 2636 2637 spin_lock_init(&tun->lock); 2638 2639 err = security_tun_dev_alloc_security(&tun->security); 2640 if (err < 0) 2641 goto err_free_stat; 2642 2643 tun_net_init(dev); 2644 tun_flow_init(tun); 2645 2646 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 2647 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 2648 NETIF_F_HW_VLAN_STAG_TX; 2649 dev->features = dev->hw_features | NETIF_F_LLTX; 2650 dev->vlan_features = dev->features & 2651 ~(NETIF_F_HW_VLAN_CTAG_TX | 2652 NETIF_F_HW_VLAN_STAG_TX); 2653 2654 INIT_LIST_HEAD(&tun->disabled); 2655 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI); 2656 if (err < 0) 2657 goto err_free_flow; 2658 2659 err = register_netdevice(tun->dev); 2660 if (err < 0) 2661 goto err_detach; 2662 } 2663 2664 netif_carrier_on(tun->dev); 2665 2666 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 2667 2668 tun->flags = (tun->flags & ~TUN_FEATURES) | 2669 (ifr->ifr_flags & TUN_FEATURES); 2670 2671 /* Make sure persistent devices do not get stuck in 2672 * xoff state. 2673 */ 2674 if (netif_running(tun->dev)) 2675 netif_tx_wake_all_queues(tun->dev); 2676 2677 strcpy(ifr->ifr_name, tun->dev->name); 2678 return 0; 2679 2680 err_detach: 2681 tun_detach_all(dev); 2682 /* register_netdevice() already called tun_free_netdev() */ 2683 goto err_free_dev; 2684 2685 err_free_flow: 2686 tun_flow_uninit(tun); 2687 security_tun_dev_free_security(tun->security); 2688 err_free_stat: 2689 free_percpu(tun->pcpu_stats); 2690 err_free_dev: 2691 free_netdev(dev); 2692 return err; 2693 } 2694 2695 static void tun_get_iff(struct net *net, struct tun_struct *tun, 2696 struct ifreq *ifr) 2697 { 2698 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 2699 2700 strcpy(ifr->ifr_name, tun->dev->name); 2701 2702 ifr->ifr_flags = tun_flags(tun); 2703 2704 } 2705 2706 /* This is like a cut-down ethtool ops, except done via tun fd so no 2707 * privs required. */ 2708 static int set_offload(struct tun_struct *tun, unsigned long arg) 2709 { 2710 netdev_features_t features = 0; 2711 2712 if (arg & TUN_F_CSUM) { 2713 features |= NETIF_F_HW_CSUM; 2714 arg &= ~TUN_F_CSUM; 2715 2716 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 2717 if (arg & TUN_F_TSO_ECN) { 2718 features |= NETIF_F_TSO_ECN; 2719 arg &= ~TUN_F_TSO_ECN; 2720 } 2721 if (arg & TUN_F_TSO4) 2722 features |= NETIF_F_TSO; 2723 if (arg & TUN_F_TSO6) 2724 features |= NETIF_F_TSO6; 2725 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 2726 } 2727 2728 arg &= ~TUN_F_UFO; 2729 } 2730 2731 /* This gives the user a way to test for new features in future by 2732 * trying to set them. */ 2733 if (arg) 2734 return -EINVAL; 2735 2736 tun->set_features = features; 2737 tun->dev->wanted_features &= ~TUN_USER_FEATURES; 2738 tun->dev->wanted_features |= features; 2739 netdev_update_features(tun->dev); 2740 2741 return 0; 2742 } 2743 2744 static void tun_detach_filter(struct tun_struct *tun, int n) 2745 { 2746 int i; 2747 struct tun_file *tfile; 2748 2749 for (i = 0; i < n; i++) { 2750 tfile = rtnl_dereference(tun->tfiles[i]); 2751 lock_sock(tfile->socket.sk); 2752 sk_detach_filter(tfile->socket.sk); 2753 release_sock(tfile->socket.sk); 2754 } 2755 2756 tun->filter_attached = false; 2757 } 2758 2759 static int tun_attach_filter(struct tun_struct *tun) 2760 { 2761 int i, ret = 0; 2762 struct tun_file *tfile; 2763 2764 for (i = 0; i < tun->numqueues; i++) { 2765 tfile = rtnl_dereference(tun->tfiles[i]); 2766 lock_sock(tfile->socket.sk); 2767 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 2768 release_sock(tfile->socket.sk); 2769 if (ret) { 2770 tun_detach_filter(tun, i); 2771 return ret; 2772 } 2773 } 2774 2775 tun->filter_attached = true; 2776 return ret; 2777 } 2778 2779 static void tun_set_sndbuf(struct tun_struct *tun) 2780 { 2781 struct tun_file *tfile; 2782 int i; 2783 2784 for (i = 0; i < tun->numqueues; i++) { 2785 tfile = rtnl_dereference(tun->tfiles[i]); 2786 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 2787 } 2788 } 2789 2790 static int tun_set_queue(struct file *file, struct ifreq *ifr) 2791 { 2792 struct tun_file *tfile = file->private_data; 2793 struct tun_struct *tun; 2794 int ret = 0; 2795 2796 rtnl_lock(); 2797 2798 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 2799 tun = tfile->detached; 2800 if (!tun) { 2801 ret = -EINVAL; 2802 goto unlock; 2803 } 2804 ret = security_tun_dev_attach_queue(tun->security); 2805 if (ret < 0) 2806 goto unlock; 2807 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI); 2808 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 2809 tun = rtnl_dereference(tfile->tun); 2810 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached) 2811 ret = -EINVAL; 2812 else 2813 __tun_detach(tfile, false); 2814 } else 2815 ret = -EINVAL; 2816 2817 unlock: 2818 rtnl_unlock(); 2819 return ret; 2820 } 2821 2822 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p, 2823 void __user *data) 2824 { 2825 struct bpf_prog *prog; 2826 int fd; 2827 2828 if (copy_from_user(&fd, data, sizeof(fd))) 2829 return -EFAULT; 2830 2831 if (fd == -1) { 2832 prog = NULL; 2833 } else { 2834 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER); 2835 if (IS_ERR(prog)) 2836 return PTR_ERR(prog); 2837 } 2838 2839 return __tun_set_ebpf(tun, prog_p, prog); 2840 } 2841 2842 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 2843 unsigned long arg, int ifreq_len) 2844 { 2845 struct tun_file *tfile = file->private_data; 2846 struct tun_struct *tun; 2847 void __user* argp = (void __user*)arg; 2848 struct ifreq ifr; 2849 struct net *net; 2850 kuid_t owner; 2851 kgid_t group; 2852 int sndbuf; 2853 int vnet_hdr_sz; 2854 unsigned int ifindex; 2855 int le; 2856 int ret; 2857 2858 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || 2859 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) { 2860 if (copy_from_user(&ifr, argp, ifreq_len)) 2861 return -EFAULT; 2862 } else { 2863 memset(&ifr, 0, sizeof(ifr)); 2864 } 2865 if (cmd == TUNGETFEATURES) { 2866 /* Currently this just means: "what IFF flags are valid?". 2867 * This is needed because we never checked for invalid flags on 2868 * TUNSETIFF. 2869 */ 2870 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES, 2871 (unsigned int __user*)argp); 2872 } else if (cmd == TUNSETQUEUE) 2873 return tun_set_queue(file, &ifr); 2874 2875 ret = 0; 2876 rtnl_lock(); 2877 2878 tun = tun_get(tfile); 2879 net = sock_net(&tfile->sk); 2880 if (cmd == TUNSETIFF) { 2881 ret = -EEXIST; 2882 if (tun) 2883 goto unlock; 2884 2885 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 2886 2887 ret = tun_set_iff(net, file, &ifr); 2888 2889 if (ret) 2890 goto unlock; 2891 2892 if (copy_to_user(argp, &ifr, ifreq_len)) 2893 ret = -EFAULT; 2894 goto unlock; 2895 } 2896 if (cmd == TUNSETIFINDEX) { 2897 ret = -EPERM; 2898 if (tun) 2899 goto unlock; 2900 2901 ret = -EFAULT; 2902 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 2903 goto unlock; 2904 2905 ret = 0; 2906 tfile->ifindex = ifindex; 2907 goto unlock; 2908 } 2909 if (cmd == SIOCGSKNS) { 2910 ret = -EPERM; 2911 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 2912 goto unlock; 2913 2914 ret = open_related_ns(&net->ns, get_net_ns); 2915 goto unlock; 2916 } 2917 2918 ret = -EBADFD; 2919 if (!tun) 2920 goto unlock; 2921 2922 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 2923 2924 ret = 0; 2925 switch (cmd) { 2926 case TUNGETIFF: 2927 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 2928 2929 if (tfile->detached) 2930 ifr.ifr_flags |= IFF_DETACH_QUEUE; 2931 if (!tfile->socket.sk->sk_filter) 2932 ifr.ifr_flags |= IFF_NOFILTER; 2933 2934 if (copy_to_user(argp, &ifr, ifreq_len)) 2935 ret = -EFAULT; 2936 break; 2937 2938 case TUNSETNOCSUM: 2939 /* Disable/Enable checksum */ 2940 2941 /* [unimplemented] */ 2942 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 2943 arg ? "disabled" : "enabled"); 2944 break; 2945 2946 case TUNSETPERSIST: 2947 /* Disable/Enable persist mode. Keep an extra reference to the 2948 * module to prevent the module being unprobed. 2949 */ 2950 if (arg && !(tun->flags & IFF_PERSIST)) { 2951 tun->flags |= IFF_PERSIST; 2952 __module_get(THIS_MODULE); 2953 } 2954 if (!arg && (tun->flags & IFF_PERSIST)) { 2955 tun->flags &= ~IFF_PERSIST; 2956 module_put(THIS_MODULE); 2957 } 2958 2959 tun_debug(KERN_INFO, tun, "persist %s\n", 2960 arg ? "enabled" : "disabled"); 2961 break; 2962 2963 case TUNSETOWNER: 2964 /* Set owner of the device */ 2965 owner = make_kuid(current_user_ns(), arg); 2966 if (!uid_valid(owner)) { 2967 ret = -EINVAL; 2968 break; 2969 } 2970 tun->owner = owner; 2971 tun_debug(KERN_INFO, tun, "owner set to %u\n", 2972 from_kuid(&init_user_ns, tun->owner)); 2973 break; 2974 2975 case TUNSETGROUP: 2976 /* Set group of the device */ 2977 group = make_kgid(current_user_ns(), arg); 2978 if (!gid_valid(group)) { 2979 ret = -EINVAL; 2980 break; 2981 } 2982 tun->group = group; 2983 tun_debug(KERN_INFO, tun, "group set to %u\n", 2984 from_kgid(&init_user_ns, tun->group)); 2985 break; 2986 2987 case TUNSETLINK: 2988 /* Only allow setting the type when the interface is down */ 2989 if (tun->dev->flags & IFF_UP) { 2990 tun_debug(KERN_INFO, tun, 2991 "Linktype set failed because interface is up\n"); 2992 ret = -EBUSY; 2993 } else { 2994 tun->dev->type = (int) arg; 2995 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 2996 tun->dev->type); 2997 ret = 0; 2998 } 2999 break; 3000 3001 #ifdef TUN_DEBUG 3002 case TUNSETDEBUG: 3003 tun->debug = arg; 3004 break; 3005 #endif 3006 case TUNSETOFFLOAD: 3007 ret = set_offload(tun, arg); 3008 break; 3009 3010 case TUNSETTXFILTER: 3011 /* Can be set only for TAPs */ 3012 ret = -EINVAL; 3013 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 3014 break; 3015 ret = update_filter(&tun->txflt, (void __user *)arg); 3016 break; 3017 3018 case SIOCGIFHWADDR: 3019 /* Get hw address */ 3020 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 3021 ifr.ifr_hwaddr.sa_family = tun->dev->type; 3022 if (copy_to_user(argp, &ifr, ifreq_len)) 3023 ret = -EFAULT; 3024 break; 3025 3026 case SIOCSIFHWADDR: 3027 /* Set hw address */ 3028 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 3029 ifr.ifr_hwaddr.sa_data); 3030 3031 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 3032 break; 3033 3034 case TUNGETSNDBUF: 3035 sndbuf = tfile->socket.sk->sk_sndbuf; 3036 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 3037 ret = -EFAULT; 3038 break; 3039 3040 case TUNSETSNDBUF: 3041 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 3042 ret = -EFAULT; 3043 break; 3044 } 3045 if (sndbuf <= 0) { 3046 ret = -EINVAL; 3047 break; 3048 } 3049 3050 tun->sndbuf = sndbuf; 3051 tun_set_sndbuf(tun); 3052 break; 3053 3054 case TUNGETVNETHDRSZ: 3055 vnet_hdr_sz = tun->vnet_hdr_sz; 3056 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 3057 ret = -EFAULT; 3058 break; 3059 3060 case TUNSETVNETHDRSZ: 3061 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 3062 ret = -EFAULT; 3063 break; 3064 } 3065 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 3066 ret = -EINVAL; 3067 break; 3068 } 3069 3070 tun->vnet_hdr_sz = vnet_hdr_sz; 3071 break; 3072 3073 case TUNGETVNETLE: 3074 le = !!(tun->flags & TUN_VNET_LE); 3075 if (put_user(le, (int __user *)argp)) 3076 ret = -EFAULT; 3077 break; 3078 3079 case TUNSETVNETLE: 3080 if (get_user(le, (int __user *)argp)) { 3081 ret = -EFAULT; 3082 break; 3083 } 3084 if (le) 3085 tun->flags |= TUN_VNET_LE; 3086 else 3087 tun->flags &= ~TUN_VNET_LE; 3088 break; 3089 3090 case TUNGETVNETBE: 3091 ret = tun_get_vnet_be(tun, argp); 3092 break; 3093 3094 case TUNSETVNETBE: 3095 ret = tun_set_vnet_be(tun, argp); 3096 break; 3097 3098 case TUNATTACHFILTER: 3099 /* Can be set only for TAPs */ 3100 ret = -EINVAL; 3101 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 3102 break; 3103 ret = -EFAULT; 3104 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 3105 break; 3106 3107 ret = tun_attach_filter(tun); 3108 break; 3109 3110 case TUNDETACHFILTER: 3111 /* Can be set only for TAPs */ 3112 ret = -EINVAL; 3113 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 3114 break; 3115 ret = 0; 3116 tun_detach_filter(tun, tun->numqueues); 3117 break; 3118 3119 case TUNGETFILTER: 3120 ret = -EINVAL; 3121 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 3122 break; 3123 ret = -EFAULT; 3124 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 3125 break; 3126 ret = 0; 3127 break; 3128 3129 case TUNSETSTEERINGEBPF: 3130 ret = tun_set_ebpf(tun, &tun->steering_prog, argp); 3131 break; 3132 3133 case TUNSETFILTEREBPF: 3134 ret = tun_set_ebpf(tun, &tun->filter_prog, argp); 3135 break; 3136 3137 default: 3138 ret = -EINVAL; 3139 break; 3140 } 3141 3142 unlock: 3143 rtnl_unlock(); 3144 if (tun) 3145 tun_put(tun); 3146 return ret; 3147 } 3148 3149 static long tun_chr_ioctl(struct file *file, 3150 unsigned int cmd, unsigned long arg) 3151 { 3152 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 3153 } 3154 3155 #ifdef CONFIG_COMPAT 3156 static long tun_chr_compat_ioctl(struct file *file, 3157 unsigned int cmd, unsigned long arg) 3158 { 3159 switch (cmd) { 3160 case TUNSETIFF: 3161 case TUNGETIFF: 3162 case TUNSETTXFILTER: 3163 case TUNGETSNDBUF: 3164 case TUNSETSNDBUF: 3165 case SIOCGIFHWADDR: 3166 case SIOCSIFHWADDR: 3167 arg = (unsigned long)compat_ptr(arg); 3168 break; 3169 default: 3170 arg = (compat_ulong_t)arg; 3171 break; 3172 } 3173 3174 /* 3175 * compat_ifreq is shorter than ifreq, so we must not access beyond 3176 * the end of that structure. All fields that are used in this 3177 * driver are compatible though, we don't need to convert the 3178 * contents. 3179 */ 3180 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 3181 } 3182 #endif /* CONFIG_COMPAT */ 3183 3184 static int tun_chr_fasync(int fd, struct file *file, int on) 3185 { 3186 struct tun_file *tfile = file->private_data; 3187 int ret; 3188 3189 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 3190 goto out; 3191 3192 if (on) { 3193 __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 3194 tfile->flags |= TUN_FASYNC; 3195 } else 3196 tfile->flags &= ~TUN_FASYNC; 3197 ret = 0; 3198 out: 3199 return ret; 3200 } 3201 3202 static int tun_chr_open(struct inode *inode, struct file * file) 3203 { 3204 struct net *net = current->nsproxy->net_ns; 3205 struct tun_file *tfile; 3206 3207 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 3208 3209 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, 3210 &tun_proto, 0); 3211 if (!tfile) 3212 return -ENOMEM; 3213 RCU_INIT_POINTER(tfile->tun, NULL); 3214 tfile->flags = 0; 3215 tfile->ifindex = 0; 3216 3217 init_waitqueue_head(&tfile->wq.wait); 3218 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq); 3219 3220 tfile->socket.file = file; 3221 tfile->socket.ops = &tun_socket_ops; 3222 3223 sock_init_data(&tfile->socket, &tfile->sk); 3224 3225 tfile->sk.sk_write_space = tun_sock_write_space; 3226 tfile->sk.sk_sndbuf = INT_MAX; 3227 3228 file->private_data = tfile; 3229 INIT_LIST_HEAD(&tfile->next); 3230 3231 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 3232 3233 memset(&tfile->tx_ring, 0, sizeof(tfile->tx_ring)); 3234 tfile->xdp_pending_pkts = 0; 3235 3236 return 0; 3237 } 3238 3239 static int tun_chr_close(struct inode *inode, struct file *file) 3240 { 3241 struct tun_file *tfile = file->private_data; 3242 3243 tun_detach(tfile, true); 3244 3245 return 0; 3246 } 3247 3248 #ifdef CONFIG_PROC_FS 3249 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file) 3250 { 3251 struct tun_file *tfile = file->private_data; 3252 struct tun_struct *tun; 3253 struct ifreq ifr; 3254 3255 memset(&ifr, 0, sizeof(ifr)); 3256 3257 rtnl_lock(); 3258 tun = tun_get(tfile); 3259 if (tun) 3260 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 3261 rtnl_unlock(); 3262 3263 if (tun) 3264 tun_put(tun); 3265 3266 seq_printf(m, "iff:\t%s\n", ifr.ifr_name); 3267 } 3268 #endif 3269 3270 static const struct file_operations tun_fops = { 3271 .owner = THIS_MODULE, 3272 .llseek = no_llseek, 3273 .read_iter = tun_chr_read_iter, 3274 .write_iter = tun_chr_write_iter, 3275 .poll = tun_chr_poll, 3276 .unlocked_ioctl = tun_chr_ioctl, 3277 #ifdef CONFIG_COMPAT 3278 .compat_ioctl = tun_chr_compat_ioctl, 3279 #endif 3280 .open = tun_chr_open, 3281 .release = tun_chr_close, 3282 .fasync = tun_chr_fasync, 3283 #ifdef CONFIG_PROC_FS 3284 .show_fdinfo = tun_chr_show_fdinfo, 3285 #endif 3286 }; 3287 3288 static struct miscdevice tun_miscdev = { 3289 .minor = TUN_MINOR, 3290 .name = "tun", 3291 .nodename = "net/tun", 3292 .fops = &tun_fops, 3293 }; 3294 3295 /* ethtool interface */ 3296 3297 static int tun_get_link_ksettings(struct net_device *dev, 3298 struct ethtool_link_ksettings *cmd) 3299 { 3300 ethtool_link_ksettings_zero_link_mode(cmd, supported); 3301 ethtool_link_ksettings_zero_link_mode(cmd, advertising); 3302 cmd->base.speed = SPEED_10; 3303 cmd->base.duplex = DUPLEX_FULL; 3304 cmd->base.port = PORT_TP; 3305 cmd->base.phy_address = 0; 3306 cmd->base.autoneg = AUTONEG_DISABLE; 3307 return 0; 3308 } 3309 3310 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 3311 { 3312 struct tun_struct *tun = netdev_priv(dev); 3313 3314 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 3315 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 3316 3317 switch (tun->flags & TUN_TYPE_MASK) { 3318 case IFF_TUN: 3319 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 3320 break; 3321 case IFF_TAP: 3322 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 3323 break; 3324 } 3325 } 3326 3327 static u32 tun_get_msglevel(struct net_device *dev) 3328 { 3329 #ifdef TUN_DEBUG 3330 struct tun_struct *tun = netdev_priv(dev); 3331 return tun->debug; 3332 #else 3333 return -EOPNOTSUPP; 3334 #endif 3335 } 3336 3337 static void tun_set_msglevel(struct net_device *dev, u32 value) 3338 { 3339 #ifdef TUN_DEBUG 3340 struct tun_struct *tun = netdev_priv(dev); 3341 tun->debug = value; 3342 #endif 3343 } 3344 3345 static int tun_get_coalesce(struct net_device *dev, 3346 struct ethtool_coalesce *ec) 3347 { 3348 struct tun_struct *tun = netdev_priv(dev); 3349 3350 ec->rx_max_coalesced_frames = tun->rx_batched; 3351 3352 return 0; 3353 } 3354 3355 static int tun_set_coalesce(struct net_device *dev, 3356 struct ethtool_coalesce *ec) 3357 { 3358 struct tun_struct *tun = netdev_priv(dev); 3359 3360 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT) 3361 tun->rx_batched = NAPI_POLL_WEIGHT; 3362 else 3363 tun->rx_batched = ec->rx_max_coalesced_frames; 3364 3365 return 0; 3366 } 3367 3368 static const struct ethtool_ops tun_ethtool_ops = { 3369 .get_drvinfo = tun_get_drvinfo, 3370 .get_msglevel = tun_get_msglevel, 3371 .set_msglevel = tun_set_msglevel, 3372 .get_link = ethtool_op_get_link, 3373 .get_ts_info = ethtool_op_get_ts_info, 3374 .get_coalesce = tun_get_coalesce, 3375 .set_coalesce = tun_set_coalesce, 3376 .get_link_ksettings = tun_get_link_ksettings, 3377 }; 3378 3379 static int tun_queue_resize(struct tun_struct *tun) 3380 { 3381 struct net_device *dev = tun->dev; 3382 struct tun_file *tfile; 3383 struct ptr_ring **rings; 3384 int n = tun->numqueues + tun->numdisabled; 3385 int ret, i; 3386 3387 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL); 3388 if (!rings) 3389 return -ENOMEM; 3390 3391 for (i = 0; i < tun->numqueues; i++) { 3392 tfile = rtnl_dereference(tun->tfiles[i]); 3393 rings[i] = &tfile->tx_ring; 3394 } 3395 list_for_each_entry(tfile, &tun->disabled, next) 3396 rings[i++] = &tfile->tx_ring; 3397 3398 ret = ptr_ring_resize_multiple(rings, n, 3399 dev->tx_queue_len, GFP_KERNEL, 3400 tun_ptr_free); 3401 3402 kfree(rings); 3403 return ret; 3404 } 3405 3406 static int tun_device_event(struct notifier_block *unused, 3407 unsigned long event, void *ptr) 3408 { 3409 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 3410 struct tun_struct *tun = netdev_priv(dev); 3411 3412 if (dev->rtnl_link_ops != &tun_link_ops) 3413 return NOTIFY_DONE; 3414 3415 switch (event) { 3416 case NETDEV_CHANGE_TX_QUEUE_LEN: 3417 if (tun_queue_resize(tun)) 3418 return NOTIFY_BAD; 3419 break; 3420 default: 3421 break; 3422 } 3423 3424 return NOTIFY_DONE; 3425 } 3426 3427 static struct notifier_block tun_notifier_block __read_mostly = { 3428 .notifier_call = tun_device_event, 3429 }; 3430 3431 static int __init tun_init(void) 3432 { 3433 int ret = 0; 3434 3435 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 3436 3437 ret = rtnl_link_register(&tun_link_ops); 3438 if (ret) { 3439 pr_err("Can't register link_ops\n"); 3440 goto err_linkops; 3441 } 3442 3443 ret = misc_register(&tun_miscdev); 3444 if (ret) { 3445 pr_err("Can't register misc device %d\n", TUN_MINOR); 3446 goto err_misc; 3447 } 3448 3449 ret = register_netdevice_notifier(&tun_notifier_block); 3450 if (ret) { 3451 pr_err("Can't register netdevice notifier\n"); 3452 goto err_notifier; 3453 } 3454 3455 return 0; 3456 3457 err_notifier: 3458 misc_deregister(&tun_miscdev); 3459 err_misc: 3460 rtnl_link_unregister(&tun_link_ops); 3461 err_linkops: 3462 return ret; 3463 } 3464 3465 static void tun_cleanup(void) 3466 { 3467 misc_deregister(&tun_miscdev); 3468 rtnl_link_unregister(&tun_link_ops); 3469 unregister_netdevice_notifier(&tun_notifier_block); 3470 } 3471 3472 /* Get an underlying socket object from tun file. Returns error unless file is 3473 * attached to a device. The returned object works like a packet socket, it 3474 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 3475 * holding a reference to the file for as long as the socket is in use. */ 3476 struct socket *tun_get_socket(struct file *file) 3477 { 3478 struct tun_file *tfile; 3479 if (file->f_op != &tun_fops) 3480 return ERR_PTR(-EINVAL); 3481 tfile = file->private_data; 3482 if (!tfile) 3483 return ERR_PTR(-EBADFD); 3484 return &tfile->socket; 3485 } 3486 EXPORT_SYMBOL_GPL(tun_get_socket); 3487 3488 struct ptr_ring *tun_get_tx_ring(struct file *file) 3489 { 3490 struct tun_file *tfile; 3491 3492 if (file->f_op != &tun_fops) 3493 return ERR_PTR(-EINVAL); 3494 tfile = file->private_data; 3495 if (!tfile) 3496 return ERR_PTR(-EBADFD); 3497 return &tfile->tx_ring; 3498 } 3499 EXPORT_SYMBOL_GPL(tun_get_tx_ring); 3500 3501 module_init(tun_init); 3502 module_exit(tun_cleanup); 3503 MODULE_DESCRIPTION(DRV_DESCRIPTION); 3504 MODULE_AUTHOR(DRV_COPYRIGHT); 3505 MODULE_LICENSE("GPL"); 3506 MODULE_ALIAS_MISCDEV(TUN_MINOR); 3507 MODULE_ALIAS("devname:net/tun"); 3508