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 77 #include <linux/uaccess.h> 78 79 /* Uncomment to enable debugging */ 80 /* #define TUN_DEBUG 1 */ 81 82 #ifdef TUN_DEBUG 83 static int debug; 84 85 #define tun_debug(level, tun, fmt, args...) \ 86 do { \ 87 if (tun->debug) \ 88 netdev_printk(level, tun->dev, fmt, ##args); \ 89 } while (0) 90 #define DBG1(level, fmt, args...) \ 91 do { \ 92 if (debug == 2) \ 93 printk(level fmt, ##args); \ 94 } while (0) 95 #else 96 #define tun_debug(level, tun, fmt, args...) \ 97 do { \ 98 if (0) \ 99 netdev_printk(level, tun->dev, fmt, ##args); \ 100 } while (0) 101 #define DBG1(level, fmt, args...) \ 102 do { \ 103 if (0) \ 104 printk(level fmt, ##args); \ 105 } while (0) 106 #endif 107 108 /* TUN device flags */ 109 110 /* IFF_ATTACH_QUEUE is never stored in device flags, 111 * overload it to mean fasync when stored there. 112 */ 113 #define TUN_FASYNC IFF_ATTACH_QUEUE 114 /* High bits in flags field are unused. */ 115 #define TUN_VNET_LE 0x80000000 116 #define TUN_VNET_BE 0x40000000 117 118 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \ 119 IFF_MULTI_QUEUE) 120 #define GOODCOPY_LEN 128 121 122 #define FLT_EXACT_COUNT 8 123 struct tap_filter { 124 unsigned int count; /* Number of addrs. Zero means disabled */ 125 u32 mask[2]; /* Mask of the hashed addrs */ 126 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 127 }; 128 129 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal 130 * to max number of VCPUs in guest. */ 131 #define MAX_TAP_QUEUES 256 132 #define MAX_TAP_FLOWS 4096 133 134 #define TUN_FLOW_EXPIRE (3 * HZ) 135 136 struct tun_pcpu_stats { 137 u64 rx_packets; 138 u64 rx_bytes; 139 u64 tx_packets; 140 u64 tx_bytes; 141 struct u64_stats_sync syncp; 142 u32 rx_dropped; 143 u32 tx_dropped; 144 u32 rx_frame_errors; 145 }; 146 147 /* A tun_file connects an open character device to a tuntap netdevice. It 148 * also contains all socket related structures (except sock_fprog and tap_filter) 149 * to serve as one transmit queue for tuntap device. The sock_fprog and 150 * tap_filter were kept in tun_struct since they were used for filtering for the 151 * netdevice not for a specific queue (at least I didn't see the requirement for 152 * this). 153 * 154 * RCU usage: 155 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 156 * other can only be read while rcu_read_lock or rtnl_lock is held. 157 */ 158 struct tun_file { 159 struct sock sk; 160 struct socket socket; 161 struct socket_wq wq; 162 struct tun_struct __rcu *tun; 163 struct fasync_struct *fasync; 164 /* only used for fasnyc */ 165 unsigned int flags; 166 union { 167 u16 queue_index; 168 unsigned int ifindex; 169 }; 170 struct list_head next; 171 struct tun_struct *detached; 172 struct skb_array tx_array; 173 }; 174 175 struct tun_flow_entry { 176 struct hlist_node hash_link; 177 struct rcu_head rcu; 178 struct tun_struct *tun; 179 180 u32 rxhash; 181 u32 rps_rxhash; 182 int queue_index; 183 unsigned long updated; 184 }; 185 186 #define TUN_NUM_FLOW_ENTRIES 1024 187 188 /* Since the socket were moved to tun_file, to preserve the behavior of persist 189 * device, socket filter, sndbuf and vnet header size were restore when the 190 * file were attached to a persist device. 191 */ 192 struct tun_struct { 193 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 194 unsigned int numqueues; 195 unsigned int flags; 196 kuid_t owner; 197 kgid_t group; 198 199 struct net_device *dev; 200 netdev_features_t set_features; 201 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 202 NETIF_F_TSO6|NETIF_F_UFO) 203 204 int align; 205 int vnet_hdr_sz; 206 int sndbuf; 207 struct tap_filter txflt; 208 struct sock_fprog fprog; 209 /* protected by rtnl lock */ 210 bool filter_attached; 211 #ifdef TUN_DEBUG 212 int debug; 213 #endif 214 spinlock_t lock; 215 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 216 struct timer_list flow_gc_timer; 217 unsigned long ageing_time; 218 unsigned int numdisabled; 219 struct list_head disabled; 220 void *security; 221 u32 flow_count; 222 u32 rx_batched; 223 struct tun_pcpu_stats __percpu *pcpu_stats; 224 }; 225 226 #ifdef CONFIG_TUN_VNET_CROSS_LE 227 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun) 228 { 229 return tun->flags & TUN_VNET_BE ? false : 230 virtio_legacy_is_little_endian(); 231 } 232 233 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp) 234 { 235 int be = !!(tun->flags & TUN_VNET_BE); 236 237 if (put_user(be, argp)) 238 return -EFAULT; 239 240 return 0; 241 } 242 243 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp) 244 { 245 int be; 246 247 if (get_user(be, argp)) 248 return -EFAULT; 249 250 if (be) 251 tun->flags |= TUN_VNET_BE; 252 else 253 tun->flags &= ~TUN_VNET_BE; 254 255 return 0; 256 } 257 #else 258 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun) 259 { 260 return virtio_legacy_is_little_endian(); 261 } 262 263 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp) 264 { 265 return -EINVAL; 266 } 267 268 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp) 269 { 270 return -EINVAL; 271 } 272 #endif /* CONFIG_TUN_VNET_CROSS_LE */ 273 274 static inline bool tun_is_little_endian(struct tun_struct *tun) 275 { 276 return tun->flags & TUN_VNET_LE || 277 tun_legacy_is_little_endian(tun); 278 } 279 280 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) 281 { 282 return __virtio16_to_cpu(tun_is_little_endian(tun), val); 283 } 284 285 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val) 286 { 287 return __cpu_to_virtio16(tun_is_little_endian(tun), val); 288 } 289 290 static inline u32 tun_hashfn(u32 rxhash) 291 { 292 return rxhash & 0x3ff; 293 } 294 295 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 296 { 297 struct tun_flow_entry *e; 298 299 hlist_for_each_entry_rcu(e, head, hash_link) { 300 if (e->rxhash == rxhash) 301 return e; 302 } 303 return NULL; 304 } 305 306 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 307 struct hlist_head *head, 308 u32 rxhash, u16 queue_index) 309 { 310 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 311 312 if (e) { 313 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 314 rxhash, queue_index); 315 e->updated = jiffies; 316 e->rxhash = rxhash; 317 e->rps_rxhash = 0; 318 e->queue_index = queue_index; 319 e->tun = tun; 320 hlist_add_head_rcu(&e->hash_link, head); 321 ++tun->flow_count; 322 } 323 return e; 324 } 325 326 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 327 { 328 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 329 e->rxhash, e->queue_index); 330 hlist_del_rcu(&e->hash_link); 331 kfree_rcu(e, rcu); 332 --tun->flow_count; 333 } 334 335 static void tun_flow_flush(struct tun_struct *tun) 336 { 337 int i; 338 339 spin_lock_bh(&tun->lock); 340 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 341 struct tun_flow_entry *e; 342 struct hlist_node *n; 343 344 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 345 tun_flow_delete(tun, e); 346 } 347 spin_unlock_bh(&tun->lock); 348 } 349 350 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 351 { 352 int i; 353 354 spin_lock_bh(&tun->lock); 355 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 356 struct tun_flow_entry *e; 357 struct hlist_node *n; 358 359 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 360 if (e->queue_index == queue_index) 361 tun_flow_delete(tun, e); 362 } 363 } 364 spin_unlock_bh(&tun->lock); 365 } 366 367 static void tun_flow_cleanup(unsigned long data) 368 { 369 struct tun_struct *tun = (struct tun_struct *)data; 370 unsigned long delay = tun->ageing_time; 371 unsigned long next_timer = jiffies + delay; 372 unsigned long count = 0; 373 int i; 374 375 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 376 377 spin_lock_bh(&tun->lock); 378 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 379 struct tun_flow_entry *e; 380 struct hlist_node *n; 381 382 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 383 unsigned long this_timer; 384 count++; 385 this_timer = e->updated + delay; 386 if (time_before_eq(this_timer, jiffies)) 387 tun_flow_delete(tun, e); 388 else if (time_before(this_timer, next_timer)) 389 next_timer = this_timer; 390 } 391 } 392 393 if (count) 394 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 395 spin_unlock_bh(&tun->lock); 396 } 397 398 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 399 struct tun_file *tfile) 400 { 401 struct hlist_head *head; 402 struct tun_flow_entry *e; 403 unsigned long delay = tun->ageing_time; 404 u16 queue_index = tfile->queue_index; 405 406 if (!rxhash) 407 return; 408 else 409 head = &tun->flows[tun_hashfn(rxhash)]; 410 411 rcu_read_lock(); 412 413 /* We may get a very small possibility of OOO during switching, not 414 * worth to optimize.*/ 415 if (tun->numqueues == 1 || tfile->detached) 416 goto unlock; 417 418 e = tun_flow_find(head, rxhash); 419 if (likely(e)) { 420 /* TODO: keep queueing to old queue until it's empty? */ 421 e->queue_index = queue_index; 422 e->updated = jiffies; 423 sock_rps_record_flow_hash(e->rps_rxhash); 424 } else { 425 spin_lock_bh(&tun->lock); 426 if (!tun_flow_find(head, rxhash) && 427 tun->flow_count < MAX_TAP_FLOWS) 428 tun_flow_create(tun, head, rxhash, queue_index); 429 430 if (!timer_pending(&tun->flow_gc_timer)) 431 mod_timer(&tun->flow_gc_timer, 432 round_jiffies_up(jiffies + delay)); 433 spin_unlock_bh(&tun->lock); 434 } 435 436 unlock: 437 rcu_read_unlock(); 438 } 439 440 /** 441 * Save the hash received in the stack receive path and update the 442 * flow_hash table accordingly. 443 */ 444 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 445 { 446 if (unlikely(e->rps_rxhash != hash)) 447 e->rps_rxhash = hash; 448 } 449 450 /* We try to identify a flow through its rxhash first. The reason that 451 * we do not check rxq no. is because some cards(e.g 82599), chooses 452 * the rxq based on the txq where the last packet of the flow comes. As 453 * the userspace application move between processors, we may get a 454 * different rxq no. here. If we could not get rxhash, then we would 455 * hope the rxq no. may help here. 456 */ 457 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, 458 void *accel_priv, select_queue_fallback_t fallback) 459 { 460 struct tun_struct *tun = netdev_priv(dev); 461 struct tun_flow_entry *e; 462 u32 txq = 0; 463 u32 numqueues = 0; 464 465 rcu_read_lock(); 466 numqueues = ACCESS_ONCE(tun->numqueues); 467 468 txq = skb_get_hash(skb); 469 if (txq) { 470 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 471 if (e) { 472 tun_flow_save_rps_rxhash(e, txq); 473 txq = e->queue_index; 474 } else 475 /* use multiply and shift instead of expensive divide */ 476 txq = ((u64)txq * numqueues) >> 32; 477 } else if (likely(skb_rx_queue_recorded(skb))) { 478 txq = skb_get_rx_queue(skb); 479 while (unlikely(txq >= numqueues)) 480 txq -= numqueues; 481 } 482 483 rcu_read_unlock(); 484 return txq; 485 } 486 487 static inline bool tun_not_capable(struct tun_struct *tun) 488 { 489 const struct cred *cred = current_cred(); 490 struct net *net = dev_net(tun->dev); 491 492 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 493 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 494 !ns_capable(net->user_ns, CAP_NET_ADMIN); 495 } 496 497 static void tun_set_real_num_queues(struct tun_struct *tun) 498 { 499 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 500 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 501 } 502 503 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 504 { 505 tfile->detached = tun; 506 list_add_tail(&tfile->next, &tun->disabled); 507 ++tun->numdisabled; 508 } 509 510 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 511 { 512 struct tun_struct *tun = tfile->detached; 513 514 tfile->detached = NULL; 515 list_del_init(&tfile->next); 516 --tun->numdisabled; 517 return tun; 518 } 519 520 static void tun_queue_purge(struct tun_file *tfile) 521 { 522 struct sk_buff *skb; 523 524 while ((skb = skb_array_consume(&tfile->tx_array)) != NULL) 525 kfree_skb(skb); 526 527 skb_queue_purge(&tfile->sk.sk_write_queue); 528 skb_queue_purge(&tfile->sk.sk_error_queue); 529 } 530 531 static void __tun_detach(struct tun_file *tfile, bool clean) 532 { 533 struct tun_file *ntfile; 534 struct tun_struct *tun; 535 536 tun = rtnl_dereference(tfile->tun); 537 538 if (tun && !tfile->detached) { 539 u16 index = tfile->queue_index; 540 BUG_ON(index >= tun->numqueues); 541 542 rcu_assign_pointer(tun->tfiles[index], 543 tun->tfiles[tun->numqueues - 1]); 544 ntfile = rtnl_dereference(tun->tfiles[index]); 545 ntfile->queue_index = index; 546 547 --tun->numqueues; 548 if (clean) { 549 RCU_INIT_POINTER(tfile->tun, NULL); 550 sock_put(&tfile->sk); 551 } else 552 tun_disable_queue(tun, tfile); 553 554 synchronize_net(); 555 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 556 /* Drop read queue */ 557 tun_queue_purge(tfile); 558 tun_set_real_num_queues(tun); 559 } else if (tfile->detached && clean) { 560 tun = tun_enable_queue(tfile); 561 sock_put(&tfile->sk); 562 } 563 564 if (clean) { 565 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 566 netif_carrier_off(tun->dev); 567 568 if (!(tun->flags & IFF_PERSIST) && 569 tun->dev->reg_state == NETREG_REGISTERED) 570 unregister_netdevice(tun->dev); 571 } 572 if (tun) 573 skb_array_cleanup(&tfile->tx_array); 574 sock_put(&tfile->sk); 575 } 576 } 577 578 static void tun_detach(struct tun_file *tfile, bool clean) 579 { 580 rtnl_lock(); 581 __tun_detach(tfile, clean); 582 rtnl_unlock(); 583 } 584 585 static void tun_detach_all(struct net_device *dev) 586 { 587 struct tun_struct *tun = netdev_priv(dev); 588 struct tun_file *tfile, *tmp; 589 int i, n = tun->numqueues; 590 591 for (i = 0; i < n; i++) { 592 tfile = rtnl_dereference(tun->tfiles[i]); 593 BUG_ON(!tfile); 594 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN; 595 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 596 RCU_INIT_POINTER(tfile->tun, NULL); 597 --tun->numqueues; 598 } 599 list_for_each_entry(tfile, &tun->disabled, next) { 600 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN; 601 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 602 RCU_INIT_POINTER(tfile->tun, NULL); 603 } 604 BUG_ON(tun->numqueues != 0); 605 606 synchronize_net(); 607 for (i = 0; i < n; i++) { 608 tfile = rtnl_dereference(tun->tfiles[i]); 609 /* Drop read queue */ 610 tun_queue_purge(tfile); 611 sock_put(&tfile->sk); 612 } 613 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 614 tun_enable_queue(tfile); 615 tun_queue_purge(tfile); 616 sock_put(&tfile->sk); 617 } 618 BUG_ON(tun->numdisabled != 0); 619 620 if (tun->flags & IFF_PERSIST) 621 module_put(THIS_MODULE); 622 } 623 624 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) 625 { 626 struct tun_file *tfile = file->private_data; 627 struct net_device *dev = tun->dev; 628 int err; 629 630 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 631 if (err < 0) 632 goto out; 633 634 err = -EINVAL; 635 if (rtnl_dereference(tfile->tun) && !tfile->detached) 636 goto out; 637 638 err = -EBUSY; 639 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1) 640 goto out; 641 642 err = -E2BIG; 643 if (!tfile->detached && 644 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 645 goto out; 646 647 err = 0; 648 649 /* Re-attach the filter to persist device */ 650 if (!skip_filter && (tun->filter_attached == true)) { 651 lock_sock(tfile->socket.sk); 652 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 653 release_sock(tfile->socket.sk); 654 if (!err) 655 goto out; 656 } 657 658 if (!tfile->detached && 659 skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL)) { 660 err = -ENOMEM; 661 goto out; 662 } 663 664 tfile->queue_index = tun->numqueues; 665 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN; 666 rcu_assign_pointer(tfile->tun, tun); 667 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 668 tun->numqueues++; 669 670 if (tfile->detached) 671 tun_enable_queue(tfile); 672 else 673 sock_hold(&tfile->sk); 674 675 tun_set_real_num_queues(tun); 676 677 /* device is allowed to go away first, so no need to hold extra 678 * refcnt. 679 */ 680 681 out: 682 return err; 683 } 684 685 static struct tun_struct *__tun_get(struct tun_file *tfile) 686 { 687 struct tun_struct *tun; 688 689 rcu_read_lock(); 690 tun = rcu_dereference(tfile->tun); 691 if (tun) 692 dev_hold(tun->dev); 693 rcu_read_unlock(); 694 695 return tun; 696 } 697 698 static struct tun_struct *tun_get(struct file *file) 699 { 700 return __tun_get(file->private_data); 701 } 702 703 static void tun_put(struct tun_struct *tun) 704 { 705 dev_put(tun->dev); 706 } 707 708 /* TAP filtering */ 709 static void addr_hash_set(u32 *mask, const u8 *addr) 710 { 711 int n = ether_crc(ETH_ALEN, addr) >> 26; 712 mask[n >> 5] |= (1 << (n & 31)); 713 } 714 715 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 716 { 717 int n = ether_crc(ETH_ALEN, addr) >> 26; 718 return mask[n >> 5] & (1 << (n & 31)); 719 } 720 721 static int update_filter(struct tap_filter *filter, void __user *arg) 722 { 723 struct { u8 u[ETH_ALEN]; } *addr; 724 struct tun_filter uf; 725 int err, alen, n, nexact; 726 727 if (copy_from_user(&uf, arg, sizeof(uf))) 728 return -EFAULT; 729 730 if (!uf.count) { 731 /* Disabled */ 732 filter->count = 0; 733 return 0; 734 } 735 736 alen = ETH_ALEN * uf.count; 737 addr = memdup_user(arg + sizeof(uf), alen); 738 if (IS_ERR(addr)) 739 return PTR_ERR(addr); 740 741 /* The filter is updated without holding any locks. Which is 742 * perfectly safe. We disable it first and in the worst 743 * case we'll accept a few undesired packets. */ 744 filter->count = 0; 745 wmb(); 746 747 /* Use first set of addresses as an exact filter */ 748 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 749 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 750 751 nexact = n; 752 753 /* Remaining multicast addresses are hashed, 754 * unicast will leave the filter disabled. */ 755 memset(filter->mask, 0, sizeof(filter->mask)); 756 for (; n < uf.count; n++) { 757 if (!is_multicast_ether_addr(addr[n].u)) { 758 err = 0; /* no filter */ 759 goto free_addr; 760 } 761 addr_hash_set(filter->mask, addr[n].u); 762 } 763 764 /* For ALLMULTI just set the mask to all ones. 765 * This overrides the mask populated above. */ 766 if ((uf.flags & TUN_FLT_ALLMULTI)) 767 memset(filter->mask, ~0, sizeof(filter->mask)); 768 769 /* Now enable the filter */ 770 wmb(); 771 filter->count = nexact; 772 773 /* Return the number of exact filters */ 774 err = nexact; 775 free_addr: 776 kfree(addr); 777 return err; 778 } 779 780 /* Returns: 0 - drop, !=0 - accept */ 781 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 782 { 783 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 784 * at this point. */ 785 struct ethhdr *eh = (struct ethhdr *) skb->data; 786 int i; 787 788 /* Exact match */ 789 for (i = 0; i < filter->count; i++) 790 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 791 return 1; 792 793 /* Inexact match (multicast only) */ 794 if (is_multicast_ether_addr(eh->h_dest)) 795 return addr_hash_test(filter->mask, eh->h_dest); 796 797 return 0; 798 } 799 800 /* 801 * Checks whether the packet is accepted or not. 802 * Returns: 0 - drop, !=0 - accept 803 */ 804 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 805 { 806 if (!filter->count) 807 return 1; 808 809 return run_filter(filter, skb); 810 } 811 812 /* Network device part of the driver */ 813 814 static const struct ethtool_ops tun_ethtool_ops; 815 816 /* Net device detach from fd. */ 817 static void tun_net_uninit(struct net_device *dev) 818 { 819 tun_detach_all(dev); 820 } 821 822 /* Net device open. */ 823 static int tun_net_open(struct net_device *dev) 824 { 825 netif_tx_start_all_queues(dev); 826 return 0; 827 } 828 829 /* Net device close. */ 830 static int tun_net_close(struct net_device *dev) 831 { 832 netif_tx_stop_all_queues(dev); 833 return 0; 834 } 835 836 /* Net device start xmit */ 837 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 838 { 839 struct tun_struct *tun = netdev_priv(dev); 840 int txq = skb->queue_mapping; 841 struct tun_file *tfile; 842 u32 numqueues = 0; 843 844 rcu_read_lock(); 845 tfile = rcu_dereference(tun->tfiles[txq]); 846 numqueues = ACCESS_ONCE(tun->numqueues); 847 848 /* Drop packet if interface is not attached */ 849 if (txq >= numqueues) 850 goto drop; 851 852 #ifdef CONFIG_RPS 853 if (numqueues == 1 && static_key_false(&rps_needed)) { 854 /* Select queue was not called for the skbuff, so we extract the 855 * RPS hash and save it into the flow_table here. 856 */ 857 __u32 rxhash; 858 859 rxhash = skb_get_hash(skb); 860 if (rxhash) { 861 struct tun_flow_entry *e; 862 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], 863 rxhash); 864 if (e) 865 tun_flow_save_rps_rxhash(e, rxhash); 866 } 867 } 868 #endif 869 870 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 871 872 BUG_ON(!tfile); 873 874 /* Drop if the filter does not like it. 875 * This is a noop if the filter is disabled. 876 * Filter can be enabled only for the TAP devices. */ 877 if (!check_filter(&tun->txflt, skb)) 878 goto drop; 879 880 if (tfile->socket.sk->sk_filter && 881 sk_filter(tfile->socket.sk, skb)) 882 goto drop; 883 884 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 885 goto drop; 886 887 skb_tx_timestamp(skb); 888 889 /* Orphan the skb - required as we might hang on to it 890 * for indefinite time. 891 */ 892 skb_orphan(skb); 893 894 nf_reset(skb); 895 896 if (skb_array_produce(&tfile->tx_array, skb)) 897 goto drop; 898 899 /* Notify and wake up reader process */ 900 if (tfile->flags & TUN_FASYNC) 901 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 902 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 903 904 rcu_read_unlock(); 905 return NETDEV_TX_OK; 906 907 drop: 908 this_cpu_inc(tun->pcpu_stats->tx_dropped); 909 skb_tx_error(skb); 910 kfree_skb(skb); 911 rcu_read_unlock(); 912 return NET_XMIT_DROP; 913 } 914 915 static void tun_net_mclist(struct net_device *dev) 916 { 917 /* 918 * This callback is supposed to deal with mc filter in 919 * _rx_ path and has nothing to do with the _tx_ path. 920 * In rx path we always accept everything userspace gives us. 921 */ 922 } 923 924 static netdev_features_t tun_net_fix_features(struct net_device *dev, 925 netdev_features_t features) 926 { 927 struct tun_struct *tun = netdev_priv(dev); 928 929 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 930 } 931 #ifdef CONFIG_NET_POLL_CONTROLLER 932 static void tun_poll_controller(struct net_device *dev) 933 { 934 /* 935 * Tun only receives frames when: 936 * 1) the char device endpoint gets data from user space 937 * 2) the tun socket gets a sendmsg call from user space 938 * Since both of those are synchronous operations, we are guaranteed 939 * never to have pending data when we poll for it 940 * so there is nothing to do here but return. 941 * We need this though so netpoll recognizes us as an interface that 942 * supports polling, which enables bridge devices in virt setups to 943 * still use netconsole 944 */ 945 return; 946 } 947 #endif 948 949 static void tun_set_headroom(struct net_device *dev, int new_hr) 950 { 951 struct tun_struct *tun = netdev_priv(dev); 952 953 if (new_hr < NET_SKB_PAD) 954 new_hr = NET_SKB_PAD; 955 956 tun->align = new_hr; 957 } 958 959 static void 960 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats) 961 { 962 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0; 963 struct tun_struct *tun = netdev_priv(dev); 964 struct tun_pcpu_stats *p; 965 int i; 966 967 for_each_possible_cpu(i) { 968 u64 rxpackets, rxbytes, txpackets, txbytes; 969 unsigned int start; 970 971 p = per_cpu_ptr(tun->pcpu_stats, i); 972 do { 973 start = u64_stats_fetch_begin(&p->syncp); 974 rxpackets = p->rx_packets; 975 rxbytes = p->rx_bytes; 976 txpackets = p->tx_packets; 977 txbytes = p->tx_bytes; 978 } while (u64_stats_fetch_retry(&p->syncp, start)); 979 980 stats->rx_packets += rxpackets; 981 stats->rx_bytes += rxbytes; 982 stats->tx_packets += txpackets; 983 stats->tx_bytes += txbytes; 984 985 /* u32 counters */ 986 rx_dropped += p->rx_dropped; 987 rx_frame_errors += p->rx_frame_errors; 988 tx_dropped += p->tx_dropped; 989 } 990 stats->rx_dropped = rx_dropped; 991 stats->rx_frame_errors = rx_frame_errors; 992 stats->tx_dropped = tx_dropped; 993 } 994 995 static const struct net_device_ops tun_netdev_ops = { 996 .ndo_uninit = tun_net_uninit, 997 .ndo_open = tun_net_open, 998 .ndo_stop = tun_net_close, 999 .ndo_start_xmit = tun_net_xmit, 1000 .ndo_fix_features = tun_net_fix_features, 1001 .ndo_select_queue = tun_select_queue, 1002 #ifdef CONFIG_NET_POLL_CONTROLLER 1003 .ndo_poll_controller = tun_poll_controller, 1004 #endif 1005 .ndo_set_rx_headroom = tun_set_headroom, 1006 .ndo_get_stats64 = tun_net_get_stats64, 1007 }; 1008 1009 static const struct net_device_ops tap_netdev_ops = { 1010 .ndo_uninit = tun_net_uninit, 1011 .ndo_open = tun_net_open, 1012 .ndo_stop = tun_net_close, 1013 .ndo_start_xmit = tun_net_xmit, 1014 .ndo_fix_features = tun_net_fix_features, 1015 .ndo_set_rx_mode = tun_net_mclist, 1016 .ndo_set_mac_address = eth_mac_addr, 1017 .ndo_validate_addr = eth_validate_addr, 1018 .ndo_select_queue = tun_select_queue, 1019 #ifdef CONFIG_NET_POLL_CONTROLLER 1020 .ndo_poll_controller = tun_poll_controller, 1021 #endif 1022 .ndo_features_check = passthru_features_check, 1023 .ndo_set_rx_headroom = tun_set_headroom, 1024 .ndo_get_stats64 = tun_net_get_stats64, 1025 }; 1026 1027 static void tun_flow_init(struct tun_struct *tun) 1028 { 1029 int i; 1030 1031 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 1032 INIT_HLIST_HEAD(&tun->flows[i]); 1033 1034 tun->ageing_time = TUN_FLOW_EXPIRE; 1035 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 1036 mod_timer(&tun->flow_gc_timer, 1037 round_jiffies_up(jiffies + tun->ageing_time)); 1038 } 1039 1040 static void tun_flow_uninit(struct tun_struct *tun) 1041 { 1042 del_timer_sync(&tun->flow_gc_timer); 1043 tun_flow_flush(tun); 1044 } 1045 1046 #define MIN_MTU 68 1047 #define MAX_MTU 65535 1048 1049 /* Initialize net device. */ 1050 static void tun_net_init(struct net_device *dev) 1051 { 1052 struct tun_struct *tun = netdev_priv(dev); 1053 1054 switch (tun->flags & TUN_TYPE_MASK) { 1055 case IFF_TUN: 1056 dev->netdev_ops = &tun_netdev_ops; 1057 1058 /* Point-to-Point TUN Device */ 1059 dev->hard_header_len = 0; 1060 dev->addr_len = 0; 1061 dev->mtu = 1500; 1062 1063 /* Zero header length */ 1064 dev->type = ARPHRD_NONE; 1065 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 1066 break; 1067 1068 case IFF_TAP: 1069 dev->netdev_ops = &tap_netdev_ops; 1070 /* Ethernet TAP Device */ 1071 ether_setup(dev); 1072 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 1073 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 1074 1075 eth_hw_addr_random(dev); 1076 1077 break; 1078 } 1079 1080 dev->min_mtu = MIN_MTU; 1081 dev->max_mtu = MAX_MTU - dev->hard_header_len; 1082 } 1083 1084 /* Character device part */ 1085 1086 /* Poll */ 1087 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 1088 { 1089 struct tun_file *tfile = file->private_data; 1090 struct tun_struct *tun = __tun_get(tfile); 1091 struct sock *sk; 1092 unsigned int mask = 0; 1093 1094 if (!tun) 1095 return POLLERR; 1096 1097 sk = tfile->socket.sk; 1098 1099 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 1100 1101 poll_wait(file, sk_sleep(sk), wait); 1102 1103 if (!skb_array_empty(&tfile->tx_array)) 1104 mask |= POLLIN | POLLRDNORM; 1105 1106 if (sock_writeable(sk) || 1107 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) && 1108 sock_writeable(sk))) 1109 mask |= POLLOUT | POLLWRNORM; 1110 1111 if (tun->dev->reg_state != NETREG_REGISTERED) 1112 mask = POLLERR; 1113 1114 tun_put(tun); 1115 return mask; 1116 } 1117 1118 /* prepad is the amount to reserve at front. len is length after that. 1119 * linear is a hint as to how much to copy (usually headers). */ 1120 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 1121 size_t prepad, size_t len, 1122 size_t linear, int noblock) 1123 { 1124 struct sock *sk = tfile->socket.sk; 1125 struct sk_buff *skb; 1126 int err; 1127 1128 /* Under a page? Don't bother with paged skb. */ 1129 if (prepad + len < PAGE_SIZE || !linear) 1130 linear = len; 1131 1132 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 1133 &err, 0); 1134 if (!skb) 1135 return ERR_PTR(err); 1136 1137 skb_reserve(skb, prepad); 1138 skb_put(skb, linear); 1139 skb->data_len = len - linear; 1140 skb->len += len - linear; 1141 1142 return skb; 1143 } 1144 1145 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile, 1146 struct sk_buff *skb, int more) 1147 { 1148 struct sk_buff_head *queue = &tfile->sk.sk_write_queue; 1149 struct sk_buff_head process_queue; 1150 u32 rx_batched = tun->rx_batched; 1151 bool rcv = false; 1152 1153 if (!rx_batched || (!more && skb_queue_empty(queue))) { 1154 local_bh_disable(); 1155 netif_receive_skb(skb); 1156 local_bh_enable(); 1157 return; 1158 } 1159 1160 spin_lock(&queue->lock); 1161 if (!more || skb_queue_len(queue) == rx_batched) { 1162 __skb_queue_head_init(&process_queue); 1163 skb_queue_splice_tail_init(queue, &process_queue); 1164 rcv = true; 1165 } else { 1166 __skb_queue_tail(queue, skb); 1167 } 1168 spin_unlock(&queue->lock); 1169 1170 if (rcv) { 1171 struct sk_buff *nskb; 1172 1173 local_bh_disable(); 1174 while ((nskb = __skb_dequeue(&process_queue))) 1175 netif_receive_skb(nskb); 1176 netif_receive_skb(skb); 1177 local_bh_enable(); 1178 } 1179 } 1180 1181 /* Get packet from user space buffer */ 1182 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1183 void *msg_control, struct iov_iter *from, 1184 int noblock, bool more) 1185 { 1186 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1187 struct sk_buff *skb; 1188 size_t total_len = iov_iter_count(from); 1189 size_t len = total_len, align = tun->align, linear; 1190 struct virtio_net_hdr gso = { 0 }; 1191 struct tun_pcpu_stats *stats; 1192 int good_linear; 1193 int copylen; 1194 bool zerocopy = false; 1195 int err; 1196 u32 rxhash; 1197 1198 if (!(tun->dev->flags & IFF_UP)) 1199 return -EIO; 1200 1201 if (!(tun->flags & IFF_NO_PI)) { 1202 if (len < sizeof(pi)) 1203 return -EINVAL; 1204 len -= sizeof(pi); 1205 1206 if (!copy_from_iter_full(&pi, sizeof(pi), from)) 1207 return -EFAULT; 1208 } 1209 1210 if (tun->flags & IFF_VNET_HDR) { 1211 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz); 1212 1213 if (len < vnet_hdr_sz) 1214 return -EINVAL; 1215 len -= vnet_hdr_sz; 1216 1217 if (!copy_from_iter_full(&gso, sizeof(gso), from)) 1218 return -EFAULT; 1219 1220 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1221 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len)) 1222 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2); 1223 1224 if (tun16_to_cpu(tun, gso.hdr_len) > len) 1225 return -EINVAL; 1226 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso)); 1227 } 1228 1229 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) { 1230 align += NET_IP_ALIGN; 1231 if (unlikely(len < ETH_HLEN || 1232 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN))) 1233 return -EINVAL; 1234 } 1235 1236 good_linear = SKB_MAX_HEAD(align); 1237 1238 if (msg_control) { 1239 struct iov_iter i = *from; 1240 1241 /* There are 256 bytes to be copied in skb, so there is 1242 * enough room for skb expand head in case it is used. 1243 * The rest of the buffer is mapped from userspace. 1244 */ 1245 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN; 1246 if (copylen > good_linear) 1247 copylen = good_linear; 1248 linear = copylen; 1249 iov_iter_advance(&i, copylen); 1250 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS) 1251 zerocopy = true; 1252 } 1253 1254 if (!zerocopy) { 1255 copylen = len; 1256 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear) 1257 linear = good_linear; 1258 else 1259 linear = tun16_to_cpu(tun, gso.hdr_len); 1260 } 1261 1262 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1263 if (IS_ERR(skb)) { 1264 if (PTR_ERR(skb) != -EAGAIN) 1265 this_cpu_inc(tun->pcpu_stats->rx_dropped); 1266 return PTR_ERR(skb); 1267 } 1268 1269 if (zerocopy) 1270 err = zerocopy_sg_from_iter(skb, from); 1271 else 1272 err = skb_copy_datagram_from_iter(skb, 0, from, len); 1273 1274 if (err) { 1275 this_cpu_inc(tun->pcpu_stats->rx_dropped); 1276 kfree_skb(skb); 1277 return -EFAULT; 1278 } 1279 1280 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) { 1281 this_cpu_inc(tun->pcpu_stats->rx_frame_errors); 1282 kfree_skb(skb); 1283 return -EINVAL; 1284 } 1285 1286 switch (tun->flags & TUN_TYPE_MASK) { 1287 case IFF_TUN: 1288 if (tun->flags & IFF_NO_PI) { 1289 switch (skb->data[0] & 0xf0) { 1290 case 0x40: 1291 pi.proto = htons(ETH_P_IP); 1292 break; 1293 case 0x60: 1294 pi.proto = htons(ETH_P_IPV6); 1295 break; 1296 default: 1297 this_cpu_inc(tun->pcpu_stats->rx_dropped); 1298 kfree_skb(skb); 1299 return -EINVAL; 1300 } 1301 } 1302 1303 skb_reset_mac_header(skb); 1304 skb->protocol = pi.proto; 1305 skb->dev = tun->dev; 1306 break; 1307 case IFF_TAP: 1308 skb->protocol = eth_type_trans(skb, tun->dev); 1309 break; 1310 } 1311 1312 /* copy skb_ubuf_info for callback when skb has no error */ 1313 if (zerocopy) { 1314 skb_shinfo(skb)->destructor_arg = msg_control; 1315 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1316 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1317 } else if (msg_control) { 1318 struct ubuf_info *uarg = msg_control; 1319 uarg->callback(uarg, false); 1320 } 1321 1322 skb_reset_network_header(skb); 1323 skb_probe_transport_header(skb, 0); 1324 1325 rxhash = skb_get_hash(skb); 1326 #ifndef CONFIG_4KSTACKS 1327 tun_rx_batched(tun, tfile, skb, more); 1328 #else 1329 netif_rx_ni(skb); 1330 #endif 1331 1332 stats = get_cpu_ptr(tun->pcpu_stats); 1333 u64_stats_update_begin(&stats->syncp); 1334 stats->rx_packets++; 1335 stats->rx_bytes += len; 1336 u64_stats_update_end(&stats->syncp); 1337 put_cpu_ptr(stats); 1338 1339 tun_flow_update(tun, rxhash, tfile); 1340 return total_len; 1341 } 1342 1343 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from) 1344 { 1345 struct file *file = iocb->ki_filp; 1346 struct tun_struct *tun = tun_get(file); 1347 struct tun_file *tfile = file->private_data; 1348 ssize_t result; 1349 1350 if (!tun) 1351 return -EBADFD; 1352 1353 result = tun_get_user(tun, tfile, NULL, from, 1354 file->f_flags & O_NONBLOCK, false); 1355 1356 tun_put(tun); 1357 return result; 1358 } 1359 1360 /* Put packet to the user space buffer */ 1361 static ssize_t tun_put_user(struct tun_struct *tun, 1362 struct tun_file *tfile, 1363 struct sk_buff *skb, 1364 struct iov_iter *iter) 1365 { 1366 struct tun_pi pi = { 0, skb->protocol }; 1367 struct tun_pcpu_stats *stats; 1368 ssize_t total; 1369 int vlan_offset = 0; 1370 int vlan_hlen = 0; 1371 int vnet_hdr_sz = 0; 1372 1373 if (skb_vlan_tag_present(skb)) 1374 vlan_hlen = VLAN_HLEN; 1375 1376 if (tun->flags & IFF_VNET_HDR) 1377 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz); 1378 1379 total = skb->len + vlan_hlen + vnet_hdr_sz; 1380 1381 if (!(tun->flags & IFF_NO_PI)) { 1382 if (iov_iter_count(iter) < sizeof(pi)) 1383 return -EINVAL; 1384 1385 total += sizeof(pi); 1386 if (iov_iter_count(iter) < total) { 1387 /* Packet will be striped */ 1388 pi.flags |= TUN_PKT_STRIP; 1389 } 1390 1391 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi)) 1392 return -EFAULT; 1393 } 1394 1395 if (vnet_hdr_sz) { 1396 struct virtio_net_hdr gso; 1397 1398 if (iov_iter_count(iter) < vnet_hdr_sz) 1399 return -EINVAL; 1400 1401 if (virtio_net_hdr_from_skb(skb, &gso, 1402 tun_is_little_endian(tun), true)) { 1403 struct skb_shared_info *sinfo = skb_shinfo(skb); 1404 pr_err("unexpected GSO type: " 1405 "0x%x, gso_size %d, hdr_len %d\n", 1406 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size), 1407 tun16_to_cpu(tun, gso.hdr_len)); 1408 print_hex_dump(KERN_ERR, "tun: ", 1409 DUMP_PREFIX_NONE, 1410 16, 1, skb->head, 1411 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true); 1412 WARN_ON_ONCE(1); 1413 return -EINVAL; 1414 } 1415 1416 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso)) 1417 return -EFAULT; 1418 1419 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso)); 1420 } 1421 1422 if (vlan_hlen) { 1423 int ret; 1424 struct { 1425 __be16 h_vlan_proto; 1426 __be16 h_vlan_TCI; 1427 } veth; 1428 1429 veth.h_vlan_proto = skb->vlan_proto; 1430 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb)); 1431 1432 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1433 1434 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset); 1435 if (ret || !iov_iter_count(iter)) 1436 goto done; 1437 1438 ret = copy_to_iter(&veth, sizeof(veth), iter); 1439 if (ret != sizeof(veth) || !iov_iter_count(iter)) 1440 goto done; 1441 } 1442 1443 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset); 1444 1445 done: 1446 /* caller is in process context, */ 1447 stats = get_cpu_ptr(tun->pcpu_stats); 1448 u64_stats_update_begin(&stats->syncp); 1449 stats->tx_packets++; 1450 stats->tx_bytes += skb->len + vlan_hlen; 1451 u64_stats_update_end(&stats->syncp); 1452 put_cpu_ptr(tun->pcpu_stats); 1453 1454 return total; 1455 } 1456 1457 static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock, 1458 int *err) 1459 { 1460 DECLARE_WAITQUEUE(wait, current); 1461 struct sk_buff *skb = NULL; 1462 int error = 0; 1463 1464 skb = skb_array_consume(&tfile->tx_array); 1465 if (skb) 1466 goto out; 1467 if (noblock) { 1468 error = -EAGAIN; 1469 goto out; 1470 } 1471 1472 add_wait_queue(&tfile->wq.wait, &wait); 1473 current->state = TASK_INTERRUPTIBLE; 1474 1475 while (1) { 1476 skb = skb_array_consume(&tfile->tx_array); 1477 if (skb) 1478 break; 1479 if (signal_pending(current)) { 1480 error = -ERESTARTSYS; 1481 break; 1482 } 1483 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) { 1484 error = -EFAULT; 1485 break; 1486 } 1487 1488 schedule(); 1489 } 1490 1491 current->state = TASK_RUNNING; 1492 remove_wait_queue(&tfile->wq.wait, &wait); 1493 1494 out: 1495 *err = error; 1496 return skb; 1497 } 1498 1499 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1500 struct iov_iter *to, 1501 int noblock) 1502 { 1503 struct sk_buff *skb; 1504 ssize_t ret; 1505 int err; 1506 1507 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1508 1509 if (!iov_iter_count(to)) 1510 return 0; 1511 1512 /* Read frames from ring */ 1513 skb = tun_ring_recv(tfile, noblock, &err); 1514 if (!skb) 1515 return err; 1516 1517 ret = tun_put_user(tun, tfile, skb, to); 1518 if (unlikely(ret < 0)) 1519 kfree_skb(skb); 1520 else 1521 consume_skb(skb); 1522 1523 return ret; 1524 } 1525 1526 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1527 { 1528 struct file *file = iocb->ki_filp; 1529 struct tun_file *tfile = file->private_data; 1530 struct tun_struct *tun = __tun_get(tfile); 1531 ssize_t len = iov_iter_count(to), ret; 1532 1533 if (!tun) 1534 return -EBADFD; 1535 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK); 1536 ret = min_t(ssize_t, ret, len); 1537 if (ret > 0) 1538 iocb->ki_pos = ret; 1539 tun_put(tun); 1540 return ret; 1541 } 1542 1543 static void tun_free_netdev(struct net_device *dev) 1544 { 1545 struct tun_struct *tun = netdev_priv(dev); 1546 1547 BUG_ON(!(list_empty(&tun->disabled))); 1548 free_percpu(tun->pcpu_stats); 1549 tun_flow_uninit(tun); 1550 security_tun_dev_free_security(tun->security); 1551 free_netdev(dev); 1552 } 1553 1554 static void tun_setup(struct net_device *dev) 1555 { 1556 struct tun_struct *tun = netdev_priv(dev); 1557 1558 tun->owner = INVALID_UID; 1559 tun->group = INVALID_GID; 1560 1561 dev->ethtool_ops = &tun_ethtool_ops; 1562 dev->destructor = tun_free_netdev; 1563 /* We prefer our own queue length */ 1564 dev->tx_queue_len = TUN_READQ_SIZE; 1565 } 1566 1567 /* Trivial set of netlink ops to allow deleting tun or tap 1568 * device with netlink. 1569 */ 1570 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1571 { 1572 return -EINVAL; 1573 } 1574 1575 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1576 .kind = DRV_NAME, 1577 .priv_size = sizeof(struct tun_struct), 1578 .setup = tun_setup, 1579 .validate = tun_validate, 1580 }; 1581 1582 static void tun_sock_write_space(struct sock *sk) 1583 { 1584 struct tun_file *tfile; 1585 wait_queue_head_t *wqueue; 1586 1587 if (!sock_writeable(sk)) 1588 return; 1589 1590 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1591 return; 1592 1593 wqueue = sk_sleep(sk); 1594 if (wqueue && waitqueue_active(wqueue)) 1595 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1596 POLLWRNORM | POLLWRBAND); 1597 1598 tfile = container_of(sk, struct tun_file, sk); 1599 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1600 } 1601 1602 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) 1603 { 1604 int ret; 1605 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1606 struct tun_struct *tun = __tun_get(tfile); 1607 1608 if (!tun) 1609 return -EBADFD; 1610 1611 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter, 1612 m->msg_flags & MSG_DONTWAIT, 1613 m->msg_flags & MSG_MORE); 1614 tun_put(tun); 1615 return ret; 1616 } 1617 1618 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, 1619 int flags) 1620 { 1621 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1622 struct tun_struct *tun = __tun_get(tfile); 1623 int ret; 1624 1625 if (!tun) 1626 return -EBADFD; 1627 1628 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1629 ret = -EINVAL; 1630 goto out; 1631 } 1632 if (flags & MSG_ERRQUEUE) { 1633 ret = sock_recv_errqueue(sock->sk, m, total_len, 1634 SOL_PACKET, TUN_TX_TIMESTAMP); 1635 goto out; 1636 } 1637 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT); 1638 if (ret > (ssize_t)total_len) { 1639 m->msg_flags |= MSG_TRUNC; 1640 ret = flags & MSG_TRUNC ? ret : total_len; 1641 } 1642 out: 1643 tun_put(tun); 1644 return ret; 1645 } 1646 1647 static int tun_peek_len(struct socket *sock) 1648 { 1649 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1650 struct tun_struct *tun; 1651 int ret = 0; 1652 1653 tun = __tun_get(tfile); 1654 if (!tun) 1655 return 0; 1656 1657 ret = skb_array_peek_len(&tfile->tx_array); 1658 tun_put(tun); 1659 1660 return ret; 1661 } 1662 1663 /* Ops structure to mimic raw sockets with tun */ 1664 static const struct proto_ops tun_socket_ops = { 1665 .peek_len = tun_peek_len, 1666 .sendmsg = tun_sendmsg, 1667 .recvmsg = tun_recvmsg, 1668 }; 1669 1670 static struct proto tun_proto = { 1671 .name = "tun", 1672 .owner = THIS_MODULE, 1673 .obj_size = sizeof(struct tun_file), 1674 }; 1675 1676 static int tun_flags(struct tun_struct *tun) 1677 { 1678 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP); 1679 } 1680 1681 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1682 char *buf) 1683 { 1684 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1685 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1686 } 1687 1688 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1689 char *buf) 1690 { 1691 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1692 return uid_valid(tun->owner)? 1693 sprintf(buf, "%u\n", 1694 from_kuid_munged(current_user_ns(), tun->owner)): 1695 sprintf(buf, "-1\n"); 1696 } 1697 1698 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1699 char *buf) 1700 { 1701 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1702 return gid_valid(tun->group) ? 1703 sprintf(buf, "%u\n", 1704 from_kgid_munged(current_user_ns(), tun->group)): 1705 sprintf(buf, "-1\n"); 1706 } 1707 1708 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1709 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1710 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1711 1712 static struct attribute *tun_dev_attrs[] = { 1713 &dev_attr_tun_flags.attr, 1714 &dev_attr_owner.attr, 1715 &dev_attr_group.attr, 1716 NULL 1717 }; 1718 1719 static const struct attribute_group tun_attr_group = { 1720 .attrs = tun_dev_attrs 1721 }; 1722 1723 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1724 { 1725 struct tun_struct *tun; 1726 struct tun_file *tfile = file->private_data; 1727 struct net_device *dev; 1728 int err; 1729 1730 if (tfile->detached) 1731 return -EINVAL; 1732 1733 dev = __dev_get_by_name(net, ifr->ifr_name); 1734 if (dev) { 1735 if (ifr->ifr_flags & IFF_TUN_EXCL) 1736 return -EBUSY; 1737 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1738 tun = netdev_priv(dev); 1739 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1740 tun = netdev_priv(dev); 1741 else 1742 return -EINVAL; 1743 1744 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1745 !!(tun->flags & IFF_MULTI_QUEUE)) 1746 return -EINVAL; 1747 1748 if (tun_not_capable(tun)) 1749 return -EPERM; 1750 err = security_tun_dev_open(tun->security); 1751 if (err < 0) 1752 return err; 1753 1754 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1755 if (err < 0) 1756 return err; 1757 1758 if (tun->flags & IFF_MULTI_QUEUE && 1759 (tun->numqueues + tun->numdisabled > 1)) { 1760 /* One or more queue has already been attached, no need 1761 * to initialize the device again. 1762 */ 1763 return 0; 1764 } 1765 } 1766 else { 1767 char *name; 1768 unsigned long flags = 0; 1769 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1770 MAX_TAP_QUEUES : 1; 1771 1772 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1773 return -EPERM; 1774 err = security_tun_dev_create(); 1775 if (err < 0) 1776 return err; 1777 1778 /* Set dev type */ 1779 if (ifr->ifr_flags & IFF_TUN) { 1780 /* TUN device */ 1781 flags |= IFF_TUN; 1782 name = "tun%d"; 1783 } else if (ifr->ifr_flags & IFF_TAP) { 1784 /* TAP device */ 1785 flags |= IFF_TAP; 1786 name = "tap%d"; 1787 } else 1788 return -EINVAL; 1789 1790 if (*ifr->ifr_name) 1791 name = ifr->ifr_name; 1792 1793 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1794 NET_NAME_UNKNOWN, tun_setup, queues, 1795 queues); 1796 1797 if (!dev) 1798 return -ENOMEM; 1799 1800 dev_net_set(dev, net); 1801 dev->rtnl_link_ops = &tun_link_ops; 1802 dev->ifindex = tfile->ifindex; 1803 dev->sysfs_groups[0] = &tun_attr_group; 1804 1805 tun = netdev_priv(dev); 1806 tun->dev = dev; 1807 tun->flags = flags; 1808 tun->txflt.count = 0; 1809 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1810 1811 tun->align = NET_SKB_PAD; 1812 tun->filter_attached = false; 1813 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1814 tun->rx_batched = 0; 1815 1816 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats); 1817 if (!tun->pcpu_stats) { 1818 err = -ENOMEM; 1819 goto err_free_dev; 1820 } 1821 1822 spin_lock_init(&tun->lock); 1823 1824 err = security_tun_dev_alloc_security(&tun->security); 1825 if (err < 0) 1826 goto err_free_stat; 1827 1828 tun_net_init(dev); 1829 tun_flow_init(tun); 1830 1831 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1832 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1833 NETIF_F_HW_VLAN_STAG_TX; 1834 dev->features = dev->hw_features | NETIF_F_LLTX; 1835 dev->vlan_features = dev->features & 1836 ~(NETIF_F_HW_VLAN_CTAG_TX | 1837 NETIF_F_HW_VLAN_STAG_TX); 1838 1839 INIT_LIST_HEAD(&tun->disabled); 1840 err = tun_attach(tun, file, false); 1841 if (err < 0) 1842 goto err_free_flow; 1843 1844 err = register_netdevice(tun->dev); 1845 if (err < 0) 1846 goto err_detach; 1847 } 1848 1849 netif_carrier_on(tun->dev); 1850 1851 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1852 1853 tun->flags = (tun->flags & ~TUN_FEATURES) | 1854 (ifr->ifr_flags & TUN_FEATURES); 1855 1856 /* Make sure persistent devices do not get stuck in 1857 * xoff state. 1858 */ 1859 if (netif_running(tun->dev)) 1860 netif_tx_wake_all_queues(tun->dev); 1861 1862 strcpy(ifr->ifr_name, tun->dev->name); 1863 return 0; 1864 1865 err_detach: 1866 tun_detach_all(dev); 1867 err_free_flow: 1868 tun_flow_uninit(tun); 1869 security_tun_dev_free_security(tun->security); 1870 err_free_stat: 1871 free_percpu(tun->pcpu_stats); 1872 err_free_dev: 1873 free_netdev(dev); 1874 return err; 1875 } 1876 1877 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1878 struct ifreq *ifr) 1879 { 1880 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1881 1882 strcpy(ifr->ifr_name, tun->dev->name); 1883 1884 ifr->ifr_flags = tun_flags(tun); 1885 1886 } 1887 1888 /* This is like a cut-down ethtool ops, except done via tun fd so no 1889 * privs required. */ 1890 static int set_offload(struct tun_struct *tun, unsigned long arg) 1891 { 1892 netdev_features_t features = 0; 1893 1894 if (arg & TUN_F_CSUM) { 1895 features |= NETIF_F_HW_CSUM; 1896 arg &= ~TUN_F_CSUM; 1897 1898 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1899 if (arg & TUN_F_TSO_ECN) { 1900 features |= NETIF_F_TSO_ECN; 1901 arg &= ~TUN_F_TSO_ECN; 1902 } 1903 if (arg & TUN_F_TSO4) 1904 features |= NETIF_F_TSO; 1905 if (arg & TUN_F_TSO6) 1906 features |= NETIF_F_TSO6; 1907 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1908 } 1909 1910 if (arg & TUN_F_UFO) { 1911 features |= NETIF_F_UFO; 1912 arg &= ~TUN_F_UFO; 1913 } 1914 } 1915 1916 /* This gives the user a way to test for new features in future by 1917 * trying to set them. */ 1918 if (arg) 1919 return -EINVAL; 1920 1921 tun->set_features = features; 1922 netdev_update_features(tun->dev); 1923 1924 return 0; 1925 } 1926 1927 static void tun_detach_filter(struct tun_struct *tun, int n) 1928 { 1929 int i; 1930 struct tun_file *tfile; 1931 1932 for (i = 0; i < n; i++) { 1933 tfile = rtnl_dereference(tun->tfiles[i]); 1934 lock_sock(tfile->socket.sk); 1935 sk_detach_filter(tfile->socket.sk); 1936 release_sock(tfile->socket.sk); 1937 } 1938 1939 tun->filter_attached = false; 1940 } 1941 1942 static int tun_attach_filter(struct tun_struct *tun) 1943 { 1944 int i, ret = 0; 1945 struct tun_file *tfile; 1946 1947 for (i = 0; i < tun->numqueues; i++) { 1948 tfile = rtnl_dereference(tun->tfiles[i]); 1949 lock_sock(tfile->socket.sk); 1950 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1951 release_sock(tfile->socket.sk); 1952 if (ret) { 1953 tun_detach_filter(tun, i); 1954 return ret; 1955 } 1956 } 1957 1958 tun->filter_attached = true; 1959 return ret; 1960 } 1961 1962 static void tun_set_sndbuf(struct tun_struct *tun) 1963 { 1964 struct tun_file *tfile; 1965 int i; 1966 1967 for (i = 0; i < tun->numqueues; i++) { 1968 tfile = rtnl_dereference(tun->tfiles[i]); 1969 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1970 } 1971 } 1972 1973 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1974 { 1975 struct tun_file *tfile = file->private_data; 1976 struct tun_struct *tun; 1977 int ret = 0; 1978 1979 rtnl_lock(); 1980 1981 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1982 tun = tfile->detached; 1983 if (!tun) { 1984 ret = -EINVAL; 1985 goto unlock; 1986 } 1987 ret = security_tun_dev_attach_queue(tun->security); 1988 if (ret < 0) 1989 goto unlock; 1990 ret = tun_attach(tun, file, false); 1991 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1992 tun = rtnl_dereference(tfile->tun); 1993 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached) 1994 ret = -EINVAL; 1995 else 1996 __tun_detach(tfile, false); 1997 } else 1998 ret = -EINVAL; 1999 2000 unlock: 2001 rtnl_unlock(); 2002 return ret; 2003 } 2004 2005 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 2006 unsigned long arg, int ifreq_len) 2007 { 2008 struct tun_file *tfile = file->private_data; 2009 struct tun_struct *tun; 2010 void __user* argp = (void __user*)arg; 2011 struct ifreq ifr; 2012 kuid_t owner; 2013 kgid_t group; 2014 int sndbuf; 2015 int vnet_hdr_sz; 2016 unsigned int ifindex; 2017 int le; 2018 int ret; 2019 2020 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) { 2021 if (copy_from_user(&ifr, argp, ifreq_len)) 2022 return -EFAULT; 2023 } else { 2024 memset(&ifr, 0, sizeof(ifr)); 2025 } 2026 if (cmd == TUNGETFEATURES) { 2027 /* Currently this just means: "what IFF flags are valid?". 2028 * This is needed because we never checked for invalid flags on 2029 * TUNSETIFF. 2030 */ 2031 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES, 2032 (unsigned int __user*)argp); 2033 } else if (cmd == TUNSETQUEUE) 2034 return tun_set_queue(file, &ifr); 2035 2036 ret = 0; 2037 rtnl_lock(); 2038 2039 tun = __tun_get(tfile); 2040 if (cmd == TUNSETIFF) { 2041 ret = -EEXIST; 2042 if (tun) 2043 goto unlock; 2044 2045 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 2046 2047 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr); 2048 2049 if (ret) 2050 goto unlock; 2051 2052 if (copy_to_user(argp, &ifr, ifreq_len)) 2053 ret = -EFAULT; 2054 goto unlock; 2055 } 2056 if (cmd == TUNSETIFINDEX) { 2057 ret = -EPERM; 2058 if (tun) 2059 goto unlock; 2060 2061 ret = -EFAULT; 2062 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 2063 goto unlock; 2064 2065 ret = 0; 2066 tfile->ifindex = ifindex; 2067 goto unlock; 2068 } 2069 2070 ret = -EBADFD; 2071 if (!tun) 2072 goto unlock; 2073 2074 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 2075 2076 ret = 0; 2077 switch (cmd) { 2078 case TUNGETIFF: 2079 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 2080 2081 if (tfile->detached) 2082 ifr.ifr_flags |= IFF_DETACH_QUEUE; 2083 if (!tfile->socket.sk->sk_filter) 2084 ifr.ifr_flags |= IFF_NOFILTER; 2085 2086 if (copy_to_user(argp, &ifr, ifreq_len)) 2087 ret = -EFAULT; 2088 break; 2089 2090 case TUNSETNOCSUM: 2091 /* Disable/Enable checksum */ 2092 2093 /* [unimplemented] */ 2094 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 2095 arg ? "disabled" : "enabled"); 2096 break; 2097 2098 case TUNSETPERSIST: 2099 /* Disable/Enable persist mode. Keep an extra reference to the 2100 * module to prevent the module being unprobed. 2101 */ 2102 if (arg && !(tun->flags & IFF_PERSIST)) { 2103 tun->flags |= IFF_PERSIST; 2104 __module_get(THIS_MODULE); 2105 } 2106 if (!arg && (tun->flags & IFF_PERSIST)) { 2107 tun->flags &= ~IFF_PERSIST; 2108 module_put(THIS_MODULE); 2109 } 2110 2111 tun_debug(KERN_INFO, tun, "persist %s\n", 2112 arg ? "enabled" : "disabled"); 2113 break; 2114 2115 case TUNSETOWNER: 2116 /* Set owner of the device */ 2117 owner = make_kuid(current_user_ns(), arg); 2118 if (!uid_valid(owner)) { 2119 ret = -EINVAL; 2120 break; 2121 } 2122 tun->owner = owner; 2123 tun_debug(KERN_INFO, tun, "owner set to %u\n", 2124 from_kuid(&init_user_ns, tun->owner)); 2125 break; 2126 2127 case TUNSETGROUP: 2128 /* Set group of the device */ 2129 group = make_kgid(current_user_ns(), arg); 2130 if (!gid_valid(group)) { 2131 ret = -EINVAL; 2132 break; 2133 } 2134 tun->group = group; 2135 tun_debug(KERN_INFO, tun, "group set to %u\n", 2136 from_kgid(&init_user_ns, tun->group)); 2137 break; 2138 2139 case TUNSETLINK: 2140 /* Only allow setting the type when the interface is down */ 2141 if (tun->dev->flags & IFF_UP) { 2142 tun_debug(KERN_INFO, tun, 2143 "Linktype set failed because interface is up\n"); 2144 ret = -EBUSY; 2145 } else { 2146 tun->dev->type = (int) arg; 2147 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 2148 tun->dev->type); 2149 ret = 0; 2150 } 2151 break; 2152 2153 #ifdef TUN_DEBUG 2154 case TUNSETDEBUG: 2155 tun->debug = arg; 2156 break; 2157 #endif 2158 case TUNSETOFFLOAD: 2159 ret = set_offload(tun, arg); 2160 break; 2161 2162 case TUNSETTXFILTER: 2163 /* Can be set only for TAPs */ 2164 ret = -EINVAL; 2165 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2166 break; 2167 ret = update_filter(&tun->txflt, (void __user *)arg); 2168 break; 2169 2170 case SIOCGIFHWADDR: 2171 /* Get hw address */ 2172 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 2173 ifr.ifr_hwaddr.sa_family = tun->dev->type; 2174 if (copy_to_user(argp, &ifr, ifreq_len)) 2175 ret = -EFAULT; 2176 break; 2177 2178 case SIOCSIFHWADDR: 2179 /* Set hw address */ 2180 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 2181 ifr.ifr_hwaddr.sa_data); 2182 2183 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2184 break; 2185 2186 case TUNGETSNDBUF: 2187 sndbuf = tfile->socket.sk->sk_sndbuf; 2188 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2189 ret = -EFAULT; 2190 break; 2191 2192 case TUNSETSNDBUF: 2193 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2194 ret = -EFAULT; 2195 break; 2196 } 2197 2198 tun->sndbuf = sndbuf; 2199 tun_set_sndbuf(tun); 2200 break; 2201 2202 case TUNGETVNETHDRSZ: 2203 vnet_hdr_sz = tun->vnet_hdr_sz; 2204 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2205 ret = -EFAULT; 2206 break; 2207 2208 case TUNSETVNETHDRSZ: 2209 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2210 ret = -EFAULT; 2211 break; 2212 } 2213 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2214 ret = -EINVAL; 2215 break; 2216 } 2217 2218 tun->vnet_hdr_sz = vnet_hdr_sz; 2219 break; 2220 2221 case TUNGETVNETLE: 2222 le = !!(tun->flags & TUN_VNET_LE); 2223 if (put_user(le, (int __user *)argp)) 2224 ret = -EFAULT; 2225 break; 2226 2227 case TUNSETVNETLE: 2228 if (get_user(le, (int __user *)argp)) { 2229 ret = -EFAULT; 2230 break; 2231 } 2232 if (le) 2233 tun->flags |= TUN_VNET_LE; 2234 else 2235 tun->flags &= ~TUN_VNET_LE; 2236 break; 2237 2238 case TUNGETVNETBE: 2239 ret = tun_get_vnet_be(tun, argp); 2240 break; 2241 2242 case TUNSETVNETBE: 2243 ret = tun_set_vnet_be(tun, argp); 2244 break; 2245 2246 case TUNATTACHFILTER: 2247 /* Can be set only for TAPs */ 2248 ret = -EINVAL; 2249 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2250 break; 2251 ret = -EFAULT; 2252 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2253 break; 2254 2255 ret = tun_attach_filter(tun); 2256 break; 2257 2258 case TUNDETACHFILTER: 2259 /* Can be set only for TAPs */ 2260 ret = -EINVAL; 2261 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2262 break; 2263 ret = 0; 2264 tun_detach_filter(tun, tun->numqueues); 2265 break; 2266 2267 case TUNGETFILTER: 2268 ret = -EINVAL; 2269 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2270 break; 2271 ret = -EFAULT; 2272 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2273 break; 2274 ret = 0; 2275 break; 2276 2277 default: 2278 ret = -EINVAL; 2279 break; 2280 } 2281 2282 unlock: 2283 rtnl_unlock(); 2284 if (tun) 2285 tun_put(tun); 2286 return ret; 2287 } 2288 2289 static long tun_chr_ioctl(struct file *file, 2290 unsigned int cmd, unsigned long arg) 2291 { 2292 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2293 } 2294 2295 #ifdef CONFIG_COMPAT 2296 static long tun_chr_compat_ioctl(struct file *file, 2297 unsigned int cmd, unsigned long arg) 2298 { 2299 switch (cmd) { 2300 case TUNSETIFF: 2301 case TUNGETIFF: 2302 case TUNSETTXFILTER: 2303 case TUNGETSNDBUF: 2304 case TUNSETSNDBUF: 2305 case SIOCGIFHWADDR: 2306 case SIOCSIFHWADDR: 2307 arg = (unsigned long)compat_ptr(arg); 2308 break; 2309 default: 2310 arg = (compat_ulong_t)arg; 2311 break; 2312 } 2313 2314 /* 2315 * compat_ifreq is shorter than ifreq, so we must not access beyond 2316 * the end of that structure. All fields that are used in this 2317 * driver are compatible though, we don't need to convert the 2318 * contents. 2319 */ 2320 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2321 } 2322 #endif /* CONFIG_COMPAT */ 2323 2324 static int tun_chr_fasync(int fd, struct file *file, int on) 2325 { 2326 struct tun_file *tfile = file->private_data; 2327 int ret; 2328 2329 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2330 goto out; 2331 2332 if (on) { 2333 __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2334 tfile->flags |= TUN_FASYNC; 2335 } else 2336 tfile->flags &= ~TUN_FASYNC; 2337 ret = 0; 2338 out: 2339 return ret; 2340 } 2341 2342 static int tun_chr_open(struct inode *inode, struct file * file) 2343 { 2344 struct net *net = current->nsproxy->net_ns; 2345 struct tun_file *tfile; 2346 2347 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2348 2349 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, 2350 &tun_proto, 0); 2351 if (!tfile) 2352 return -ENOMEM; 2353 RCU_INIT_POINTER(tfile->tun, NULL); 2354 tfile->flags = 0; 2355 tfile->ifindex = 0; 2356 2357 init_waitqueue_head(&tfile->wq.wait); 2358 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq); 2359 2360 tfile->socket.file = file; 2361 tfile->socket.ops = &tun_socket_ops; 2362 2363 sock_init_data(&tfile->socket, &tfile->sk); 2364 2365 tfile->sk.sk_write_space = tun_sock_write_space; 2366 tfile->sk.sk_sndbuf = INT_MAX; 2367 2368 file->private_data = tfile; 2369 INIT_LIST_HEAD(&tfile->next); 2370 2371 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2372 2373 return 0; 2374 } 2375 2376 static int tun_chr_close(struct inode *inode, struct file *file) 2377 { 2378 struct tun_file *tfile = file->private_data; 2379 2380 tun_detach(tfile, true); 2381 2382 return 0; 2383 } 2384 2385 #ifdef CONFIG_PROC_FS 2386 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f) 2387 { 2388 struct tun_struct *tun; 2389 struct ifreq ifr; 2390 2391 memset(&ifr, 0, sizeof(ifr)); 2392 2393 rtnl_lock(); 2394 tun = tun_get(f); 2395 if (tun) 2396 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 2397 rtnl_unlock(); 2398 2399 if (tun) 2400 tun_put(tun); 2401 2402 seq_printf(m, "iff:\t%s\n", ifr.ifr_name); 2403 } 2404 #endif 2405 2406 static const struct file_operations tun_fops = { 2407 .owner = THIS_MODULE, 2408 .llseek = no_llseek, 2409 .read_iter = tun_chr_read_iter, 2410 .write_iter = tun_chr_write_iter, 2411 .poll = tun_chr_poll, 2412 .unlocked_ioctl = tun_chr_ioctl, 2413 #ifdef CONFIG_COMPAT 2414 .compat_ioctl = tun_chr_compat_ioctl, 2415 #endif 2416 .open = tun_chr_open, 2417 .release = tun_chr_close, 2418 .fasync = tun_chr_fasync, 2419 #ifdef CONFIG_PROC_FS 2420 .show_fdinfo = tun_chr_show_fdinfo, 2421 #endif 2422 }; 2423 2424 static struct miscdevice tun_miscdev = { 2425 .minor = TUN_MINOR, 2426 .name = "tun", 2427 .nodename = "net/tun", 2428 .fops = &tun_fops, 2429 }; 2430 2431 /* ethtool interface */ 2432 2433 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2434 { 2435 cmd->supported = 0; 2436 cmd->advertising = 0; 2437 ethtool_cmd_speed_set(cmd, SPEED_10); 2438 cmd->duplex = DUPLEX_FULL; 2439 cmd->port = PORT_TP; 2440 cmd->phy_address = 0; 2441 cmd->transceiver = XCVR_INTERNAL; 2442 cmd->autoneg = AUTONEG_DISABLE; 2443 cmd->maxtxpkt = 0; 2444 cmd->maxrxpkt = 0; 2445 return 0; 2446 } 2447 2448 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2449 { 2450 struct tun_struct *tun = netdev_priv(dev); 2451 2452 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2453 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2454 2455 switch (tun->flags & TUN_TYPE_MASK) { 2456 case IFF_TUN: 2457 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2458 break; 2459 case IFF_TAP: 2460 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2461 break; 2462 } 2463 } 2464 2465 static u32 tun_get_msglevel(struct net_device *dev) 2466 { 2467 #ifdef TUN_DEBUG 2468 struct tun_struct *tun = netdev_priv(dev); 2469 return tun->debug; 2470 #else 2471 return -EOPNOTSUPP; 2472 #endif 2473 } 2474 2475 static void tun_set_msglevel(struct net_device *dev, u32 value) 2476 { 2477 #ifdef TUN_DEBUG 2478 struct tun_struct *tun = netdev_priv(dev); 2479 tun->debug = value; 2480 #endif 2481 } 2482 2483 static int tun_get_coalesce(struct net_device *dev, 2484 struct ethtool_coalesce *ec) 2485 { 2486 struct tun_struct *tun = netdev_priv(dev); 2487 2488 ec->rx_max_coalesced_frames = tun->rx_batched; 2489 2490 return 0; 2491 } 2492 2493 static int tun_set_coalesce(struct net_device *dev, 2494 struct ethtool_coalesce *ec) 2495 { 2496 struct tun_struct *tun = netdev_priv(dev); 2497 2498 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT) 2499 tun->rx_batched = NAPI_POLL_WEIGHT; 2500 else 2501 tun->rx_batched = ec->rx_max_coalesced_frames; 2502 2503 return 0; 2504 } 2505 2506 static const struct ethtool_ops tun_ethtool_ops = { 2507 .get_settings = tun_get_settings, 2508 .get_drvinfo = tun_get_drvinfo, 2509 .get_msglevel = tun_get_msglevel, 2510 .set_msglevel = tun_set_msglevel, 2511 .get_link = ethtool_op_get_link, 2512 .get_ts_info = ethtool_op_get_ts_info, 2513 .get_coalesce = tun_get_coalesce, 2514 .set_coalesce = tun_set_coalesce, 2515 }; 2516 2517 static int tun_queue_resize(struct tun_struct *tun) 2518 { 2519 struct net_device *dev = tun->dev; 2520 struct tun_file *tfile; 2521 struct skb_array **arrays; 2522 int n = tun->numqueues + tun->numdisabled; 2523 int ret, i; 2524 2525 arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL); 2526 if (!arrays) 2527 return -ENOMEM; 2528 2529 for (i = 0; i < tun->numqueues; i++) { 2530 tfile = rtnl_dereference(tun->tfiles[i]); 2531 arrays[i] = &tfile->tx_array; 2532 } 2533 list_for_each_entry(tfile, &tun->disabled, next) 2534 arrays[i++] = &tfile->tx_array; 2535 2536 ret = skb_array_resize_multiple(arrays, n, 2537 dev->tx_queue_len, GFP_KERNEL); 2538 2539 kfree(arrays); 2540 return ret; 2541 } 2542 2543 static int tun_device_event(struct notifier_block *unused, 2544 unsigned long event, void *ptr) 2545 { 2546 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 2547 struct tun_struct *tun = netdev_priv(dev); 2548 2549 if (dev->rtnl_link_ops != &tun_link_ops) 2550 return NOTIFY_DONE; 2551 2552 switch (event) { 2553 case NETDEV_CHANGE_TX_QUEUE_LEN: 2554 if (tun_queue_resize(tun)) 2555 return NOTIFY_BAD; 2556 break; 2557 default: 2558 break; 2559 } 2560 2561 return NOTIFY_DONE; 2562 } 2563 2564 static struct notifier_block tun_notifier_block __read_mostly = { 2565 .notifier_call = tun_device_event, 2566 }; 2567 2568 static int __init tun_init(void) 2569 { 2570 int ret = 0; 2571 2572 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2573 pr_info("%s\n", DRV_COPYRIGHT); 2574 2575 ret = rtnl_link_register(&tun_link_ops); 2576 if (ret) { 2577 pr_err("Can't register link_ops\n"); 2578 goto err_linkops; 2579 } 2580 2581 ret = misc_register(&tun_miscdev); 2582 if (ret) { 2583 pr_err("Can't register misc device %d\n", TUN_MINOR); 2584 goto err_misc; 2585 } 2586 2587 register_netdevice_notifier(&tun_notifier_block); 2588 return 0; 2589 err_misc: 2590 rtnl_link_unregister(&tun_link_ops); 2591 err_linkops: 2592 return ret; 2593 } 2594 2595 static void tun_cleanup(void) 2596 { 2597 misc_deregister(&tun_miscdev); 2598 rtnl_link_unregister(&tun_link_ops); 2599 unregister_netdevice_notifier(&tun_notifier_block); 2600 } 2601 2602 /* Get an underlying socket object from tun file. Returns error unless file is 2603 * attached to a device. The returned object works like a packet socket, it 2604 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2605 * holding a reference to the file for as long as the socket is in use. */ 2606 struct socket *tun_get_socket(struct file *file) 2607 { 2608 struct tun_file *tfile; 2609 if (file->f_op != &tun_fops) 2610 return ERR_PTR(-EINVAL); 2611 tfile = file->private_data; 2612 if (!tfile) 2613 return ERR_PTR(-EBADFD); 2614 return &tfile->socket; 2615 } 2616 EXPORT_SYMBOL_GPL(tun_get_socket); 2617 2618 module_init(tun_init); 2619 module_exit(tun_cleanup); 2620 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2621 MODULE_AUTHOR(DRV_COPYRIGHT); 2622 MODULE_LICENSE("GPL"); 2623 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2624 MODULE_ALIAS("devname:net/tun"); 2625