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/major.h> 48 #include <linux/slab.h> 49 #include <linux/poll.h> 50 #include <linux/fcntl.h> 51 #include <linux/init.h> 52 #include <linux/skbuff.h> 53 #include <linux/netdevice.h> 54 #include <linux/etherdevice.h> 55 #include <linux/miscdevice.h> 56 #include <linux/ethtool.h> 57 #include <linux/rtnetlink.h> 58 #include <linux/compat.h> 59 #include <linux/if.h> 60 #include <linux/if_arp.h> 61 #include <linux/if_ether.h> 62 #include <linux/if_tun.h> 63 #include <linux/if_vlan.h> 64 #include <linux/crc32.h> 65 #include <linux/nsproxy.h> 66 #include <linux/virtio_net.h> 67 #include <linux/rcupdate.h> 68 #include <net/net_namespace.h> 69 #include <net/netns/generic.h> 70 #include <net/rtnetlink.h> 71 #include <net/sock.h> 72 73 #include <asm/uaccess.h> 74 75 /* Uncomment to enable debugging */ 76 /* #define TUN_DEBUG 1 */ 77 78 #ifdef TUN_DEBUG 79 static int debug; 80 81 #define tun_debug(level, tun, fmt, args...) \ 82 do { \ 83 if (tun->debug) \ 84 netdev_printk(level, tun->dev, fmt, ##args); \ 85 } while (0) 86 #define DBG1(level, fmt, args...) \ 87 do { \ 88 if (debug == 2) \ 89 printk(level fmt, ##args); \ 90 } while (0) 91 #else 92 #define tun_debug(level, tun, fmt, args...) \ 93 do { \ 94 if (0) \ 95 netdev_printk(level, tun->dev, fmt, ##args); \ 96 } while (0) 97 #define DBG1(level, fmt, args...) \ 98 do { \ 99 if (0) \ 100 printk(level fmt, ##args); \ 101 } while (0) 102 #endif 103 104 #define GOODCOPY_LEN 128 105 106 #define FLT_EXACT_COUNT 8 107 struct tap_filter { 108 unsigned int count; /* Number of addrs. Zero means disabled */ 109 u32 mask[2]; /* Mask of the hashed addrs */ 110 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 111 }; 112 113 /* DEFAULT_MAX_NUM_RSS_QUEUES were choosed to let the rx/tx queues allocated for 114 * the netdevice to be fit in one page. So we can make sure the success of 115 * memory allocation. TODO: increase the limit. */ 116 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES 117 #define MAX_TAP_FLOWS 4096 118 119 #define TUN_FLOW_EXPIRE (3 * HZ) 120 121 /* A tun_file connects an open character device to a tuntap netdevice. It 122 * also contains all socket related strctures (except sock_fprog and tap_filter) 123 * to serve as one transmit queue for tuntap device. The sock_fprog and 124 * tap_filter were kept in tun_struct since they were used for filtering for the 125 * netdevice not for a specific queue (at least I didn't see the requirement for 126 * this). 127 * 128 * RCU usage: 129 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 130 * other can only be read while rcu_read_lock or rtnl_lock is held. 131 */ 132 struct tun_file { 133 struct sock sk; 134 struct socket socket; 135 struct socket_wq wq; 136 struct tun_struct __rcu *tun; 137 struct net *net; 138 struct fasync_struct *fasync; 139 /* only used for fasnyc */ 140 unsigned int flags; 141 union { 142 u16 queue_index; 143 unsigned int ifindex; 144 }; 145 struct list_head next; 146 struct tun_struct *detached; 147 }; 148 149 struct tun_flow_entry { 150 struct hlist_node hash_link; 151 struct rcu_head rcu; 152 struct tun_struct *tun; 153 154 u32 rxhash; 155 int queue_index; 156 unsigned long updated; 157 }; 158 159 #define TUN_NUM_FLOW_ENTRIES 1024 160 161 /* Since the socket were moved to tun_file, to preserve the behavior of persist 162 * device, socket filter, sndbuf and vnet header size were restore when the 163 * file were attached to a persist device. 164 */ 165 struct tun_struct { 166 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 167 unsigned int numqueues; 168 unsigned int flags; 169 kuid_t owner; 170 kgid_t group; 171 172 struct net_device *dev; 173 netdev_features_t set_features; 174 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 175 NETIF_F_TSO6|NETIF_F_UFO) 176 177 int vnet_hdr_sz; 178 int sndbuf; 179 struct tap_filter txflt; 180 struct sock_fprog fprog; 181 /* protected by rtnl lock */ 182 bool filter_attached; 183 #ifdef TUN_DEBUG 184 int debug; 185 #endif 186 spinlock_t lock; 187 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 188 struct timer_list flow_gc_timer; 189 unsigned long ageing_time; 190 unsigned int numdisabled; 191 struct list_head disabled; 192 void *security; 193 u32 flow_count; 194 }; 195 196 static inline u32 tun_hashfn(u32 rxhash) 197 { 198 return rxhash & 0x3ff; 199 } 200 201 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 202 { 203 struct tun_flow_entry *e; 204 205 hlist_for_each_entry_rcu(e, head, hash_link) { 206 if (e->rxhash == rxhash) 207 return e; 208 } 209 return NULL; 210 } 211 212 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 213 struct hlist_head *head, 214 u32 rxhash, u16 queue_index) 215 { 216 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 217 218 if (e) { 219 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 220 rxhash, queue_index); 221 e->updated = jiffies; 222 e->rxhash = rxhash; 223 e->queue_index = queue_index; 224 e->tun = tun; 225 hlist_add_head_rcu(&e->hash_link, head); 226 ++tun->flow_count; 227 } 228 return e; 229 } 230 231 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 232 { 233 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 234 e->rxhash, e->queue_index); 235 hlist_del_rcu(&e->hash_link); 236 kfree_rcu(e, rcu); 237 --tun->flow_count; 238 } 239 240 static void tun_flow_flush(struct tun_struct *tun) 241 { 242 int i; 243 244 spin_lock_bh(&tun->lock); 245 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 246 struct tun_flow_entry *e; 247 struct hlist_node *n; 248 249 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 250 tun_flow_delete(tun, e); 251 } 252 spin_unlock_bh(&tun->lock); 253 } 254 255 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 256 { 257 int i; 258 259 spin_lock_bh(&tun->lock); 260 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 261 struct tun_flow_entry *e; 262 struct hlist_node *n; 263 264 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 265 if (e->queue_index == queue_index) 266 tun_flow_delete(tun, e); 267 } 268 } 269 spin_unlock_bh(&tun->lock); 270 } 271 272 static void tun_flow_cleanup(unsigned long data) 273 { 274 struct tun_struct *tun = (struct tun_struct *)data; 275 unsigned long delay = tun->ageing_time; 276 unsigned long next_timer = jiffies + delay; 277 unsigned long count = 0; 278 int i; 279 280 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 281 282 spin_lock_bh(&tun->lock); 283 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 284 struct tun_flow_entry *e; 285 struct hlist_node *n; 286 287 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 288 unsigned long this_timer; 289 count++; 290 this_timer = e->updated + delay; 291 if (time_before_eq(this_timer, jiffies)) 292 tun_flow_delete(tun, e); 293 else if (time_before(this_timer, next_timer)) 294 next_timer = this_timer; 295 } 296 } 297 298 if (count) 299 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 300 spin_unlock_bh(&tun->lock); 301 } 302 303 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 304 struct tun_file *tfile) 305 { 306 struct hlist_head *head; 307 struct tun_flow_entry *e; 308 unsigned long delay = tun->ageing_time; 309 u16 queue_index = tfile->queue_index; 310 311 if (!rxhash) 312 return; 313 else 314 head = &tun->flows[tun_hashfn(rxhash)]; 315 316 rcu_read_lock(); 317 318 /* We may get a very small possibility of OOO during switching, not 319 * worth to optimize.*/ 320 if (tun->numqueues == 1 || tfile->detached) 321 goto unlock; 322 323 e = tun_flow_find(head, rxhash); 324 if (likely(e)) { 325 /* TODO: keep queueing to old queue until it's empty? */ 326 e->queue_index = queue_index; 327 e->updated = jiffies; 328 } else { 329 spin_lock_bh(&tun->lock); 330 if (!tun_flow_find(head, rxhash) && 331 tun->flow_count < MAX_TAP_FLOWS) 332 tun_flow_create(tun, head, rxhash, queue_index); 333 334 if (!timer_pending(&tun->flow_gc_timer)) 335 mod_timer(&tun->flow_gc_timer, 336 round_jiffies_up(jiffies + delay)); 337 spin_unlock_bh(&tun->lock); 338 } 339 340 unlock: 341 rcu_read_unlock(); 342 } 343 344 /* We try to identify a flow through its rxhash first. The reason that 345 * we do not check rxq no. is becuase some cards(e.g 82599), chooses 346 * the rxq based on the txq where the last packet of the flow comes. As 347 * the userspace application move between processors, we may get a 348 * different rxq no. here. If we could not get rxhash, then we would 349 * hope the rxq no. may help here. 350 */ 351 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb) 352 { 353 struct tun_struct *tun = netdev_priv(dev); 354 struct tun_flow_entry *e; 355 u32 txq = 0; 356 u32 numqueues = 0; 357 358 rcu_read_lock(); 359 numqueues = ACCESS_ONCE(tun->numqueues); 360 361 txq = skb_get_rxhash(skb); 362 if (txq) { 363 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 364 if (e) 365 txq = e->queue_index; 366 else 367 /* use multiply and shift instead of expensive divide */ 368 txq = ((u64)txq * numqueues) >> 32; 369 } else if (likely(skb_rx_queue_recorded(skb))) { 370 txq = skb_get_rx_queue(skb); 371 while (unlikely(txq >= numqueues)) 372 txq -= numqueues; 373 } 374 375 rcu_read_unlock(); 376 return txq; 377 } 378 379 static inline bool tun_not_capable(struct tun_struct *tun) 380 { 381 const struct cred *cred = current_cred(); 382 struct net *net = dev_net(tun->dev); 383 384 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 385 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 386 !ns_capable(net->user_ns, CAP_NET_ADMIN); 387 } 388 389 static void tun_set_real_num_queues(struct tun_struct *tun) 390 { 391 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 392 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 393 } 394 395 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 396 { 397 tfile->detached = tun; 398 list_add_tail(&tfile->next, &tun->disabled); 399 ++tun->numdisabled; 400 } 401 402 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 403 { 404 struct tun_struct *tun = tfile->detached; 405 406 tfile->detached = NULL; 407 list_del_init(&tfile->next); 408 --tun->numdisabled; 409 return tun; 410 } 411 412 static void tun_queue_purge(struct tun_file *tfile) 413 { 414 skb_queue_purge(&tfile->sk.sk_receive_queue); 415 skb_queue_purge(&tfile->sk.sk_error_queue); 416 } 417 418 static void __tun_detach(struct tun_file *tfile, bool clean) 419 { 420 struct tun_file *ntfile; 421 struct tun_struct *tun; 422 423 tun = rtnl_dereference(tfile->tun); 424 425 if (tun && !tfile->detached) { 426 u16 index = tfile->queue_index; 427 BUG_ON(index >= tun->numqueues); 428 429 rcu_assign_pointer(tun->tfiles[index], 430 tun->tfiles[tun->numqueues - 1]); 431 ntfile = rtnl_dereference(tun->tfiles[index]); 432 ntfile->queue_index = index; 433 434 --tun->numqueues; 435 if (clean) { 436 rcu_assign_pointer(tfile->tun, NULL); 437 sock_put(&tfile->sk); 438 } else 439 tun_disable_queue(tun, tfile); 440 441 synchronize_net(); 442 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 443 /* Drop read queue */ 444 tun_queue_purge(tfile); 445 tun_set_real_num_queues(tun); 446 } else if (tfile->detached && clean) { 447 tun = tun_enable_queue(tfile); 448 sock_put(&tfile->sk); 449 } 450 451 if (clean) { 452 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 453 netif_carrier_off(tun->dev); 454 455 if (!(tun->flags & TUN_PERSIST) && 456 tun->dev->reg_state == NETREG_REGISTERED) 457 unregister_netdevice(tun->dev); 458 } 459 460 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 461 &tfile->socket.flags)); 462 sk_release_kernel(&tfile->sk); 463 } 464 } 465 466 static void tun_detach(struct tun_file *tfile, bool clean) 467 { 468 rtnl_lock(); 469 __tun_detach(tfile, clean); 470 rtnl_unlock(); 471 } 472 473 static void tun_detach_all(struct net_device *dev) 474 { 475 struct tun_struct *tun = netdev_priv(dev); 476 struct tun_file *tfile, *tmp; 477 int i, n = tun->numqueues; 478 479 for (i = 0; i < n; i++) { 480 tfile = rtnl_dereference(tun->tfiles[i]); 481 BUG_ON(!tfile); 482 wake_up_all(&tfile->wq.wait); 483 rcu_assign_pointer(tfile->tun, NULL); 484 --tun->numqueues; 485 } 486 list_for_each_entry(tfile, &tun->disabled, next) { 487 wake_up_all(&tfile->wq.wait); 488 rcu_assign_pointer(tfile->tun, NULL); 489 } 490 BUG_ON(tun->numqueues != 0); 491 492 synchronize_net(); 493 for (i = 0; i < n; i++) { 494 tfile = rtnl_dereference(tun->tfiles[i]); 495 /* Drop read queue */ 496 tun_queue_purge(tfile); 497 sock_put(&tfile->sk); 498 } 499 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 500 tun_enable_queue(tfile); 501 tun_queue_purge(tfile); 502 sock_put(&tfile->sk); 503 } 504 BUG_ON(tun->numdisabled != 0); 505 506 if (tun->flags & TUN_PERSIST) 507 module_put(THIS_MODULE); 508 } 509 510 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) 511 { 512 struct tun_file *tfile = file->private_data; 513 int err; 514 515 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 516 if (err < 0) 517 goto out; 518 519 err = -EINVAL; 520 if (rtnl_dereference(tfile->tun) && !tfile->detached) 521 goto out; 522 523 err = -EBUSY; 524 if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1) 525 goto out; 526 527 err = -E2BIG; 528 if (!tfile->detached && 529 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 530 goto out; 531 532 err = 0; 533 534 /* Re-attach the filter to presist device */ 535 if (!skip_filter && (tun->filter_attached == true)) { 536 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 537 if (!err) 538 goto out; 539 } 540 tfile->queue_index = tun->numqueues; 541 rcu_assign_pointer(tfile->tun, tun); 542 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 543 tun->numqueues++; 544 545 if (tfile->detached) 546 tun_enable_queue(tfile); 547 else 548 sock_hold(&tfile->sk); 549 550 tun_set_real_num_queues(tun); 551 552 /* device is allowed to go away first, so no need to hold extra 553 * refcnt. 554 */ 555 556 out: 557 return err; 558 } 559 560 static struct tun_struct *__tun_get(struct tun_file *tfile) 561 { 562 struct tun_struct *tun; 563 564 rcu_read_lock(); 565 tun = rcu_dereference(tfile->tun); 566 if (tun) 567 dev_hold(tun->dev); 568 rcu_read_unlock(); 569 570 return tun; 571 } 572 573 static struct tun_struct *tun_get(struct file *file) 574 { 575 return __tun_get(file->private_data); 576 } 577 578 static void tun_put(struct tun_struct *tun) 579 { 580 dev_put(tun->dev); 581 } 582 583 /* TAP filtering */ 584 static void addr_hash_set(u32 *mask, const u8 *addr) 585 { 586 int n = ether_crc(ETH_ALEN, addr) >> 26; 587 mask[n >> 5] |= (1 << (n & 31)); 588 } 589 590 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 591 { 592 int n = ether_crc(ETH_ALEN, addr) >> 26; 593 return mask[n >> 5] & (1 << (n & 31)); 594 } 595 596 static int update_filter(struct tap_filter *filter, void __user *arg) 597 { 598 struct { u8 u[ETH_ALEN]; } *addr; 599 struct tun_filter uf; 600 int err, alen, n, nexact; 601 602 if (copy_from_user(&uf, arg, sizeof(uf))) 603 return -EFAULT; 604 605 if (!uf.count) { 606 /* Disabled */ 607 filter->count = 0; 608 return 0; 609 } 610 611 alen = ETH_ALEN * uf.count; 612 addr = kmalloc(alen, GFP_KERNEL); 613 if (!addr) 614 return -ENOMEM; 615 616 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 617 err = -EFAULT; 618 goto done; 619 } 620 621 /* The filter is updated without holding any locks. Which is 622 * perfectly safe. We disable it first and in the worst 623 * case we'll accept a few undesired packets. */ 624 filter->count = 0; 625 wmb(); 626 627 /* Use first set of addresses as an exact filter */ 628 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 629 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 630 631 nexact = n; 632 633 /* Remaining multicast addresses are hashed, 634 * unicast will leave the filter disabled. */ 635 memset(filter->mask, 0, sizeof(filter->mask)); 636 for (; n < uf.count; n++) { 637 if (!is_multicast_ether_addr(addr[n].u)) { 638 err = 0; /* no filter */ 639 goto done; 640 } 641 addr_hash_set(filter->mask, addr[n].u); 642 } 643 644 /* For ALLMULTI just set the mask to all ones. 645 * This overrides the mask populated above. */ 646 if ((uf.flags & TUN_FLT_ALLMULTI)) 647 memset(filter->mask, ~0, sizeof(filter->mask)); 648 649 /* Now enable the filter */ 650 wmb(); 651 filter->count = nexact; 652 653 /* Return the number of exact filters */ 654 err = nexact; 655 656 done: 657 kfree(addr); 658 return err; 659 } 660 661 /* Returns: 0 - drop, !=0 - accept */ 662 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 663 { 664 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 665 * at this point. */ 666 struct ethhdr *eh = (struct ethhdr *) skb->data; 667 int i; 668 669 /* Exact match */ 670 for (i = 0; i < filter->count; i++) 671 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 672 return 1; 673 674 /* Inexact match (multicast only) */ 675 if (is_multicast_ether_addr(eh->h_dest)) 676 return addr_hash_test(filter->mask, eh->h_dest); 677 678 return 0; 679 } 680 681 /* 682 * Checks whether the packet is accepted or not. 683 * Returns: 0 - drop, !=0 - accept 684 */ 685 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 686 { 687 if (!filter->count) 688 return 1; 689 690 return run_filter(filter, skb); 691 } 692 693 /* Network device part of the driver */ 694 695 static const struct ethtool_ops tun_ethtool_ops; 696 697 /* Net device detach from fd. */ 698 static void tun_net_uninit(struct net_device *dev) 699 { 700 tun_detach_all(dev); 701 } 702 703 /* Net device open. */ 704 static int tun_net_open(struct net_device *dev) 705 { 706 netif_tx_start_all_queues(dev); 707 return 0; 708 } 709 710 /* Net device close. */ 711 static int tun_net_close(struct net_device *dev) 712 { 713 netif_tx_stop_all_queues(dev); 714 return 0; 715 } 716 717 /* Net device start xmit */ 718 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 719 { 720 struct tun_struct *tun = netdev_priv(dev); 721 int txq = skb->queue_mapping; 722 struct tun_file *tfile; 723 724 rcu_read_lock(); 725 tfile = rcu_dereference(tun->tfiles[txq]); 726 727 /* Drop packet if interface is not attached */ 728 if (txq >= tun->numqueues) 729 goto drop; 730 731 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 732 733 BUG_ON(!tfile); 734 735 /* Drop if the filter does not like it. 736 * This is a noop if the filter is disabled. 737 * Filter can be enabled only for the TAP devices. */ 738 if (!check_filter(&tun->txflt, skb)) 739 goto drop; 740 741 if (tfile->socket.sk->sk_filter && 742 sk_filter(tfile->socket.sk, skb)) 743 goto drop; 744 745 /* Limit the number of packets queued by dividing txq length with the 746 * number of queues. 747 */ 748 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) 749 >= dev->tx_queue_len / tun->numqueues) 750 goto drop; 751 752 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 753 goto drop; 754 755 if (skb->sk) { 756 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags); 757 sw_tx_timestamp(skb); 758 } 759 760 /* Orphan the skb - required as we might hang on to it 761 * for indefinite time. 762 */ 763 skb_orphan(skb); 764 765 nf_reset(skb); 766 767 /* Enqueue packet */ 768 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 769 770 /* Notify and wake up reader process */ 771 if (tfile->flags & TUN_FASYNC) 772 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 773 wake_up_interruptible_poll(&tfile->wq.wait, POLLIN | 774 POLLRDNORM | POLLRDBAND); 775 776 rcu_read_unlock(); 777 return NETDEV_TX_OK; 778 779 drop: 780 dev->stats.tx_dropped++; 781 skb_tx_error(skb); 782 kfree_skb(skb); 783 rcu_read_unlock(); 784 return NETDEV_TX_OK; 785 } 786 787 static void tun_net_mclist(struct net_device *dev) 788 { 789 /* 790 * This callback is supposed to deal with mc filter in 791 * _rx_ path and has nothing to do with the _tx_ path. 792 * In rx path we always accept everything userspace gives us. 793 */ 794 } 795 796 #define MIN_MTU 68 797 #define MAX_MTU 65535 798 799 static int 800 tun_net_change_mtu(struct net_device *dev, int new_mtu) 801 { 802 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 803 return -EINVAL; 804 dev->mtu = new_mtu; 805 return 0; 806 } 807 808 static netdev_features_t tun_net_fix_features(struct net_device *dev, 809 netdev_features_t features) 810 { 811 struct tun_struct *tun = netdev_priv(dev); 812 813 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 814 } 815 #ifdef CONFIG_NET_POLL_CONTROLLER 816 static void tun_poll_controller(struct net_device *dev) 817 { 818 /* 819 * Tun only receives frames when: 820 * 1) the char device endpoint gets data from user space 821 * 2) the tun socket gets a sendmsg call from user space 822 * Since both of those are syncronous operations, we are guaranteed 823 * never to have pending data when we poll for it 824 * so theres nothing to do here but return. 825 * We need this though so netpoll recognizes us as an interface that 826 * supports polling, which enables bridge devices in virt setups to 827 * still use netconsole 828 */ 829 return; 830 } 831 #endif 832 static const struct net_device_ops tun_netdev_ops = { 833 .ndo_uninit = tun_net_uninit, 834 .ndo_open = tun_net_open, 835 .ndo_stop = tun_net_close, 836 .ndo_start_xmit = tun_net_xmit, 837 .ndo_change_mtu = tun_net_change_mtu, 838 .ndo_fix_features = tun_net_fix_features, 839 .ndo_select_queue = tun_select_queue, 840 #ifdef CONFIG_NET_POLL_CONTROLLER 841 .ndo_poll_controller = tun_poll_controller, 842 #endif 843 }; 844 845 static const struct net_device_ops tap_netdev_ops = { 846 .ndo_uninit = tun_net_uninit, 847 .ndo_open = tun_net_open, 848 .ndo_stop = tun_net_close, 849 .ndo_start_xmit = tun_net_xmit, 850 .ndo_change_mtu = tun_net_change_mtu, 851 .ndo_fix_features = tun_net_fix_features, 852 .ndo_set_rx_mode = tun_net_mclist, 853 .ndo_set_mac_address = eth_mac_addr, 854 .ndo_validate_addr = eth_validate_addr, 855 .ndo_select_queue = tun_select_queue, 856 #ifdef CONFIG_NET_POLL_CONTROLLER 857 .ndo_poll_controller = tun_poll_controller, 858 #endif 859 }; 860 861 static void tun_flow_init(struct tun_struct *tun) 862 { 863 int i; 864 865 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 866 INIT_HLIST_HEAD(&tun->flows[i]); 867 868 tun->ageing_time = TUN_FLOW_EXPIRE; 869 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 870 mod_timer(&tun->flow_gc_timer, 871 round_jiffies_up(jiffies + tun->ageing_time)); 872 } 873 874 static void tun_flow_uninit(struct tun_struct *tun) 875 { 876 del_timer_sync(&tun->flow_gc_timer); 877 tun_flow_flush(tun); 878 } 879 880 /* Initialize net device. */ 881 static void tun_net_init(struct net_device *dev) 882 { 883 struct tun_struct *tun = netdev_priv(dev); 884 885 switch (tun->flags & TUN_TYPE_MASK) { 886 case TUN_TUN_DEV: 887 dev->netdev_ops = &tun_netdev_ops; 888 889 /* Point-to-Point TUN Device */ 890 dev->hard_header_len = 0; 891 dev->addr_len = 0; 892 dev->mtu = 1500; 893 894 /* Zero header length */ 895 dev->type = ARPHRD_NONE; 896 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 897 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 898 break; 899 900 case TUN_TAP_DEV: 901 dev->netdev_ops = &tap_netdev_ops; 902 /* Ethernet TAP Device */ 903 ether_setup(dev); 904 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 905 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 906 907 eth_hw_addr_random(dev); 908 909 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 910 break; 911 } 912 } 913 914 /* Character device part */ 915 916 /* Poll */ 917 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 918 { 919 struct tun_file *tfile = file->private_data; 920 struct tun_struct *tun = __tun_get(tfile); 921 struct sock *sk; 922 unsigned int mask = 0; 923 924 if (!tun) 925 return POLLERR; 926 927 sk = tfile->socket.sk; 928 929 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 930 931 poll_wait(file, &tfile->wq.wait, wait); 932 933 if (!skb_queue_empty(&sk->sk_receive_queue)) 934 mask |= POLLIN | POLLRDNORM; 935 936 if (sock_writeable(sk) || 937 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 938 sock_writeable(sk))) 939 mask |= POLLOUT | POLLWRNORM; 940 941 if (tun->dev->reg_state != NETREG_REGISTERED) 942 mask = POLLERR; 943 944 tun_put(tun); 945 return mask; 946 } 947 948 /* prepad is the amount to reserve at front. len is length after that. 949 * linear is a hint as to how much to copy (usually headers). */ 950 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 951 size_t prepad, size_t len, 952 size_t linear, int noblock) 953 { 954 struct sock *sk = tfile->socket.sk; 955 struct sk_buff *skb; 956 int err; 957 958 /* Under a page? Don't bother with paged skb. */ 959 if (prepad + len < PAGE_SIZE || !linear) 960 linear = len; 961 962 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 963 &err, 0); 964 if (!skb) 965 return ERR_PTR(err); 966 967 skb_reserve(skb, prepad); 968 skb_put(skb, linear); 969 skb->data_len = len - linear; 970 skb->len += len - linear; 971 972 return skb; 973 } 974 975 /* Get packet from user space buffer */ 976 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 977 void *msg_control, const struct iovec *iv, 978 size_t total_len, size_t count, int noblock) 979 { 980 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 981 struct sk_buff *skb; 982 size_t len = total_len, align = NET_SKB_PAD, linear; 983 struct virtio_net_hdr gso = { 0 }; 984 int good_linear; 985 int offset = 0; 986 int copylen; 987 bool zerocopy = false; 988 int err; 989 u32 rxhash; 990 991 if (!(tun->flags & TUN_NO_PI)) { 992 if (len < sizeof(pi)) 993 return -EINVAL; 994 len -= sizeof(pi); 995 996 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) 997 return -EFAULT; 998 offset += sizeof(pi); 999 } 1000 1001 if (tun->flags & TUN_VNET_HDR) { 1002 if (len < tun->vnet_hdr_sz) 1003 return -EINVAL; 1004 len -= tun->vnet_hdr_sz; 1005 1006 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) 1007 return -EFAULT; 1008 1009 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1010 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) 1011 gso.hdr_len = gso.csum_start + gso.csum_offset + 2; 1012 1013 if (gso.hdr_len > len) 1014 return -EINVAL; 1015 offset += tun->vnet_hdr_sz; 1016 } 1017 1018 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { 1019 align += NET_IP_ALIGN; 1020 if (unlikely(len < ETH_HLEN || 1021 (gso.hdr_len && gso.hdr_len < ETH_HLEN))) 1022 return -EINVAL; 1023 } 1024 1025 good_linear = SKB_MAX_HEAD(align); 1026 1027 if (msg_control) { 1028 /* There are 256 bytes to be copied in skb, so there is 1029 * enough room for skb expand head in case it is used. 1030 * The rest of the buffer is mapped from userspace. 1031 */ 1032 copylen = gso.hdr_len ? gso.hdr_len : GOODCOPY_LEN; 1033 if (copylen > good_linear) 1034 copylen = good_linear; 1035 linear = copylen; 1036 if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS) 1037 zerocopy = true; 1038 } 1039 1040 if (!zerocopy) { 1041 copylen = len; 1042 if (gso.hdr_len > good_linear) 1043 linear = good_linear; 1044 else 1045 linear = gso.hdr_len; 1046 } 1047 1048 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1049 if (IS_ERR(skb)) { 1050 if (PTR_ERR(skb) != -EAGAIN) 1051 tun->dev->stats.rx_dropped++; 1052 return PTR_ERR(skb); 1053 } 1054 1055 if (zerocopy) 1056 err = zerocopy_sg_from_iovec(skb, iv, offset, count); 1057 else { 1058 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len); 1059 if (!err && msg_control) { 1060 struct ubuf_info *uarg = msg_control; 1061 uarg->callback(uarg, false); 1062 } 1063 } 1064 1065 if (err) { 1066 tun->dev->stats.rx_dropped++; 1067 kfree_skb(skb); 1068 return -EFAULT; 1069 } 1070 1071 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1072 if (!skb_partial_csum_set(skb, gso.csum_start, 1073 gso.csum_offset)) { 1074 tun->dev->stats.rx_frame_errors++; 1075 kfree_skb(skb); 1076 return -EINVAL; 1077 } 1078 } 1079 1080 switch (tun->flags & TUN_TYPE_MASK) { 1081 case TUN_TUN_DEV: 1082 if (tun->flags & TUN_NO_PI) { 1083 switch (skb->data[0] & 0xf0) { 1084 case 0x40: 1085 pi.proto = htons(ETH_P_IP); 1086 break; 1087 case 0x60: 1088 pi.proto = htons(ETH_P_IPV6); 1089 break; 1090 default: 1091 tun->dev->stats.rx_dropped++; 1092 kfree_skb(skb); 1093 return -EINVAL; 1094 } 1095 } 1096 1097 skb_reset_mac_header(skb); 1098 skb->protocol = pi.proto; 1099 skb->dev = tun->dev; 1100 break; 1101 case TUN_TAP_DEV: 1102 skb->protocol = eth_type_trans(skb, tun->dev); 1103 break; 1104 } 1105 1106 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1107 pr_debug("GSO!\n"); 1108 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1109 case VIRTIO_NET_HDR_GSO_TCPV4: 1110 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1111 break; 1112 case VIRTIO_NET_HDR_GSO_TCPV6: 1113 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1114 break; 1115 case VIRTIO_NET_HDR_GSO_UDP: 1116 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1117 break; 1118 default: 1119 tun->dev->stats.rx_frame_errors++; 1120 kfree_skb(skb); 1121 return -EINVAL; 1122 } 1123 1124 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1125 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1126 1127 skb_shinfo(skb)->gso_size = gso.gso_size; 1128 if (skb_shinfo(skb)->gso_size == 0) { 1129 tun->dev->stats.rx_frame_errors++; 1130 kfree_skb(skb); 1131 return -EINVAL; 1132 } 1133 1134 /* Header must be checked, and gso_segs computed. */ 1135 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1136 skb_shinfo(skb)->gso_segs = 0; 1137 } 1138 1139 /* copy skb_ubuf_info for callback when skb has no error */ 1140 if (zerocopy) { 1141 skb_shinfo(skb)->destructor_arg = msg_control; 1142 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1143 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1144 } 1145 1146 skb_reset_network_header(skb); 1147 skb_probe_transport_header(skb, 0); 1148 1149 rxhash = skb_get_rxhash(skb); 1150 netif_rx_ni(skb); 1151 1152 tun->dev->stats.rx_packets++; 1153 tun->dev->stats.rx_bytes += len; 1154 1155 tun_flow_update(tun, rxhash, tfile); 1156 return total_len; 1157 } 1158 1159 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 1160 unsigned long count, loff_t pos) 1161 { 1162 struct file *file = iocb->ki_filp; 1163 struct tun_struct *tun = tun_get(file); 1164 struct tun_file *tfile = file->private_data; 1165 ssize_t result; 1166 1167 if (!tun) 1168 return -EBADFD; 1169 1170 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count); 1171 1172 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count), 1173 count, file->f_flags & O_NONBLOCK); 1174 1175 tun_put(tun); 1176 return result; 1177 } 1178 1179 /* Put packet to the user space buffer */ 1180 static ssize_t tun_put_user(struct tun_struct *tun, 1181 struct tun_file *tfile, 1182 struct sk_buff *skb, 1183 const struct iovec *iv, int len) 1184 { 1185 struct tun_pi pi = { 0, skb->protocol }; 1186 ssize_t total = 0; 1187 int vlan_offset = 0; 1188 1189 if (!(tun->flags & TUN_NO_PI)) { 1190 if ((len -= sizeof(pi)) < 0) 1191 return -EINVAL; 1192 1193 if (len < skb->len) { 1194 /* Packet will be striped */ 1195 pi.flags |= TUN_PKT_STRIP; 1196 } 1197 1198 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi))) 1199 return -EFAULT; 1200 total += sizeof(pi); 1201 } 1202 1203 if (tun->flags & TUN_VNET_HDR) { 1204 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1205 if ((len -= tun->vnet_hdr_sz) < 0) 1206 return -EINVAL; 1207 1208 if (skb_is_gso(skb)) { 1209 struct skb_shared_info *sinfo = skb_shinfo(skb); 1210 1211 /* This is a hint as to how much should be linear. */ 1212 gso.hdr_len = skb_headlen(skb); 1213 gso.gso_size = sinfo->gso_size; 1214 if (sinfo->gso_type & SKB_GSO_TCPV4) 1215 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1216 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1217 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1218 else if (sinfo->gso_type & SKB_GSO_UDP) 1219 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1220 else { 1221 pr_err("unexpected GSO type: " 1222 "0x%x, gso_size %d, hdr_len %d\n", 1223 sinfo->gso_type, gso.gso_size, 1224 gso.hdr_len); 1225 print_hex_dump(KERN_ERR, "tun: ", 1226 DUMP_PREFIX_NONE, 1227 16, 1, skb->head, 1228 min((int)gso.hdr_len, 64), true); 1229 WARN_ON_ONCE(1); 1230 return -EINVAL; 1231 } 1232 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1233 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1234 } else 1235 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1236 1237 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1238 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1239 gso.csum_start = skb_checksum_start_offset(skb); 1240 gso.csum_offset = skb->csum_offset; 1241 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1242 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1243 } /* else everything is zero */ 1244 1245 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, 1246 sizeof(gso)))) 1247 return -EFAULT; 1248 total += tun->vnet_hdr_sz; 1249 } 1250 1251 if (!vlan_tx_tag_present(skb)) { 1252 len = min_t(int, skb->len, len); 1253 } else { 1254 int copy, ret; 1255 struct { 1256 __be16 h_vlan_proto; 1257 __be16 h_vlan_TCI; 1258 } veth; 1259 1260 veth.h_vlan_proto = skb->vlan_proto; 1261 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 1262 1263 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1264 len = min_t(int, skb->len + VLAN_HLEN, len); 1265 1266 copy = min_t(int, vlan_offset, len); 1267 ret = skb_copy_datagram_const_iovec(skb, 0, iv, total, copy); 1268 len -= copy; 1269 total += copy; 1270 if (ret || !len) 1271 goto done; 1272 1273 copy = min_t(int, sizeof(veth), len); 1274 ret = memcpy_toiovecend(iv, (void *)&veth, total, copy); 1275 len -= copy; 1276 total += copy; 1277 if (ret || !len) 1278 goto done; 1279 } 1280 1281 skb_copy_datagram_const_iovec(skb, vlan_offset, iv, total, len); 1282 total += len; 1283 1284 done: 1285 tun->dev->stats.tx_packets++; 1286 tun->dev->stats.tx_bytes += len; 1287 1288 return total; 1289 } 1290 1291 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1292 struct kiocb *iocb, const struct iovec *iv, 1293 ssize_t len, int noblock) 1294 { 1295 DECLARE_WAITQUEUE(wait, current); 1296 struct sk_buff *skb; 1297 ssize_t ret = 0; 1298 1299 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1300 1301 if (unlikely(!noblock)) 1302 add_wait_queue(&tfile->wq.wait, &wait); 1303 while (len) { 1304 if (unlikely(!noblock)) 1305 current->state = TASK_INTERRUPTIBLE; 1306 1307 /* Read frames from the queue */ 1308 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) { 1309 if (noblock) { 1310 ret = -EAGAIN; 1311 break; 1312 } 1313 if (signal_pending(current)) { 1314 ret = -ERESTARTSYS; 1315 break; 1316 } 1317 if (tun->dev->reg_state != NETREG_REGISTERED) { 1318 ret = -EIO; 1319 break; 1320 } 1321 1322 /* Nothing to read, let's sleep */ 1323 schedule(); 1324 continue; 1325 } 1326 1327 ret = tun_put_user(tun, tfile, skb, iv, len); 1328 kfree_skb(skb); 1329 break; 1330 } 1331 1332 if (unlikely(!noblock)) { 1333 current->state = TASK_RUNNING; 1334 remove_wait_queue(&tfile->wq.wait, &wait); 1335 } 1336 1337 return ret; 1338 } 1339 1340 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 1341 unsigned long count, loff_t pos) 1342 { 1343 struct file *file = iocb->ki_filp; 1344 struct tun_file *tfile = file->private_data; 1345 struct tun_struct *tun = __tun_get(tfile); 1346 ssize_t len, ret; 1347 1348 if (!tun) 1349 return -EBADFD; 1350 len = iov_length(iv, count); 1351 if (len < 0) { 1352 ret = -EINVAL; 1353 goto out; 1354 } 1355 1356 ret = tun_do_read(tun, tfile, iocb, iv, len, 1357 file->f_flags & O_NONBLOCK); 1358 ret = min_t(ssize_t, ret, len); 1359 out: 1360 tun_put(tun); 1361 return ret; 1362 } 1363 1364 static void tun_free_netdev(struct net_device *dev) 1365 { 1366 struct tun_struct *tun = netdev_priv(dev); 1367 1368 BUG_ON(!(list_empty(&tun->disabled))); 1369 tun_flow_uninit(tun); 1370 security_tun_dev_free_security(tun->security); 1371 free_netdev(dev); 1372 } 1373 1374 static void tun_setup(struct net_device *dev) 1375 { 1376 struct tun_struct *tun = netdev_priv(dev); 1377 1378 tun->owner = INVALID_UID; 1379 tun->group = INVALID_GID; 1380 1381 dev->ethtool_ops = &tun_ethtool_ops; 1382 dev->destructor = tun_free_netdev; 1383 } 1384 1385 /* Trivial set of netlink ops to allow deleting tun or tap 1386 * device with netlink. 1387 */ 1388 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1389 { 1390 return -EINVAL; 1391 } 1392 1393 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1394 .kind = DRV_NAME, 1395 .priv_size = sizeof(struct tun_struct), 1396 .setup = tun_setup, 1397 .validate = tun_validate, 1398 }; 1399 1400 static void tun_sock_write_space(struct sock *sk) 1401 { 1402 struct tun_file *tfile; 1403 wait_queue_head_t *wqueue; 1404 1405 if (!sock_writeable(sk)) 1406 return; 1407 1408 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1409 return; 1410 1411 wqueue = sk_sleep(sk); 1412 if (wqueue && waitqueue_active(wqueue)) 1413 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1414 POLLWRNORM | POLLWRBAND); 1415 1416 tfile = container_of(sk, struct tun_file, sk); 1417 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1418 } 1419 1420 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1421 struct msghdr *m, size_t total_len) 1422 { 1423 int ret; 1424 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1425 struct tun_struct *tun = __tun_get(tfile); 1426 1427 if (!tun) 1428 return -EBADFD; 1429 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len, 1430 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); 1431 tun_put(tun); 1432 return ret; 1433 } 1434 1435 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1436 struct msghdr *m, size_t total_len, 1437 int flags) 1438 { 1439 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1440 struct tun_struct *tun = __tun_get(tfile); 1441 int ret; 1442 1443 if (!tun) 1444 return -EBADFD; 1445 1446 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1447 ret = -EINVAL; 1448 goto out; 1449 } 1450 if (flags & MSG_ERRQUEUE) { 1451 ret = sock_recv_errqueue(sock->sk, m, total_len, 1452 SOL_PACKET, TUN_TX_TIMESTAMP); 1453 goto out; 1454 } 1455 ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len, 1456 flags & MSG_DONTWAIT); 1457 if (ret > total_len) { 1458 m->msg_flags |= MSG_TRUNC; 1459 ret = flags & MSG_TRUNC ? ret : total_len; 1460 } 1461 out: 1462 tun_put(tun); 1463 return ret; 1464 } 1465 1466 static int tun_release(struct socket *sock) 1467 { 1468 if (sock->sk) 1469 sock_put(sock->sk); 1470 return 0; 1471 } 1472 1473 /* Ops structure to mimic raw sockets with tun */ 1474 static const struct proto_ops tun_socket_ops = { 1475 .sendmsg = tun_sendmsg, 1476 .recvmsg = tun_recvmsg, 1477 .release = tun_release, 1478 }; 1479 1480 static struct proto tun_proto = { 1481 .name = "tun", 1482 .owner = THIS_MODULE, 1483 .obj_size = sizeof(struct tun_file), 1484 }; 1485 1486 static int tun_flags(struct tun_struct *tun) 1487 { 1488 int flags = 0; 1489 1490 if (tun->flags & TUN_TUN_DEV) 1491 flags |= IFF_TUN; 1492 else 1493 flags |= IFF_TAP; 1494 1495 if (tun->flags & TUN_NO_PI) 1496 flags |= IFF_NO_PI; 1497 1498 /* This flag has no real effect. We track the value for backwards 1499 * compatibility. 1500 */ 1501 if (tun->flags & TUN_ONE_QUEUE) 1502 flags |= IFF_ONE_QUEUE; 1503 1504 if (tun->flags & TUN_VNET_HDR) 1505 flags |= IFF_VNET_HDR; 1506 1507 if (tun->flags & TUN_TAP_MQ) 1508 flags |= IFF_MULTI_QUEUE; 1509 1510 if (tun->flags & TUN_PERSIST) 1511 flags |= IFF_PERSIST; 1512 1513 return flags; 1514 } 1515 1516 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1517 char *buf) 1518 { 1519 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1520 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1521 } 1522 1523 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1524 char *buf) 1525 { 1526 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1527 return uid_valid(tun->owner)? 1528 sprintf(buf, "%u\n", 1529 from_kuid_munged(current_user_ns(), tun->owner)): 1530 sprintf(buf, "-1\n"); 1531 } 1532 1533 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1534 char *buf) 1535 { 1536 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1537 return gid_valid(tun->group) ? 1538 sprintf(buf, "%u\n", 1539 from_kgid_munged(current_user_ns(), tun->group)): 1540 sprintf(buf, "-1\n"); 1541 } 1542 1543 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1544 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1545 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1546 1547 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1548 { 1549 struct tun_struct *tun; 1550 struct tun_file *tfile = file->private_data; 1551 struct net_device *dev; 1552 int err; 1553 1554 if (tfile->detached) 1555 return -EINVAL; 1556 1557 dev = __dev_get_by_name(net, ifr->ifr_name); 1558 if (dev) { 1559 if (ifr->ifr_flags & IFF_TUN_EXCL) 1560 return -EBUSY; 1561 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1562 tun = netdev_priv(dev); 1563 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1564 tun = netdev_priv(dev); 1565 else 1566 return -EINVAL; 1567 1568 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1569 !!(tun->flags & TUN_TAP_MQ)) 1570 return -EINVAL; 1571 1572 if (tun_not_capable(tun)) 1573 return -EPERM; 1574 err = security_tun_dev_open(tun->security); 1575 if (err < 0) 1576 return err; 1577 1578 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1579 if (err < 0) 1580 return err; 1581 1582 if (tun->flags & TUN_TAP_MQ && 1583 (tun->numqueues + tun->numdisabled > 1)) { 1584 /* One or more queue has already been attached, no need 1585 * to initialize the device again. 1586 */ 1587 return 0; 1588 } 1589 } 1590 else { 1591 char *name; 1592 unsigned long flags = 0; 1593 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1594 MAX_TAP_QUEUES : 1; 1595 1596 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1597 return -EPERM; 1598 err = security_tun_dev_create(); 1599 if (err < 0) 1600 return err; 1601 1602 /* Set dev type */ 1603 if (ifr->ifr_flags & IFF_TUN) { 1604 /* TUN device */ 1605 flags |= TUN_TUN_DEV; 1606 name = "tun%d"; 1607 } else if (ifr->ifr_flags & IFF_TAP) { 1608 /* TAP device */ 1609 flags |= TUN_TAP_DEV; 1610 name = "tap%d"; 1611 } else 1612 return -EINVAL; 1613 1614 if (*ifr->ifr_name) 1615 name = ifr->ifr_name; 1616 1617 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1618 tun_setup, queues, queues); 1619 1620 if (!dev) 1621 return -ENOMEM; 1622 1623 dev_net_set(dev, net); 1624 dev->rtnl_link_ops = &tun_link_ops; 1625 dev->ifindex = tfile->ifindex; 1626 1627 tun = netdev_priv(dev); 1628 tun->dev = dev; 1629 tun->flags = flags; 1630 tun->txflt.count = 0; 1631 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1632 1633 tun->filter_attached = false; 1634 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1635 1636 spin_lock_init(&tun->lock); 1637 1638 err = security_tun_dev_alloc_security(&tun->security); 1639 if (err < 0) 1640 goto err_free_dev; 1641 1642 tun_net_init(dev); 1643 tun_flow_init(tun); 1644 1645 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1646 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1647 NETIF_F_HW_VLAN_STAG_TX; 1648 dev->features = dev->hw_features; 1649 dev->vlan_features = dev->features; 1650 1651 INIT_LIST_HEAD(&tun->disabled); 1652 err = tun_attach(tun, file, false); 1653 if (err < 0) 1654 goto err_free_flow; 1655 1656 err = register_netdevice(tun->dev); 1657 if (err < 0) 1658 goto err_detach; 1659 1660 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1661 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1662 device_create_file(&tun->dev->dev, &dev_attr_group)) 1663 pr_err("Failed to create tun sysfs files\n"); 1664 } 1665 1666 netif_carrier_on(tun->dev); 1667 1668 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1669 1670 if (ifr->ifr_flags & IFF_NO_PI) 1671 tun->flags |= TUN_NO_PI; 1672 else 1673 tun->flags &= ~TUN_NO_PI; 1674 1675 /* This flag has no real effect. We track the value for backwards 1676 * compatibility. 1677 */ 1678 if (ifr->ifr_flags & IFF_ONE_QUEUE) 1679 tun->flags |= TUN_ONE_QUEUE; 1680 else 1681 tun->flags &= ~TUN_ONE_QUEUE; 1682 1683 if (ifr->ifr_flags & IFF_VNET_HDR) 1684 tun->flags |= TUN_VNET_HDR; 1685 else 1686 tun->flags &= ~TUN_VNET_HDR; 1687 1688 if (ifr->ifr_flags & IFF_MULTI_QUEUE) 1689 tun->flags |= TUN_TAP_MQ; 1690 else 1691 tun->flags &= ~TUN_TAP_MQ; 1692 1693 /* Make sure persistent devices do not get stuck in 1694 * xoff state. 1695 */ 1696 if (netif_running(tun->dev)) 1697 netif_tx_wake_all_queues(tun->dev); 1698 1699 strcpy(ifr->ifr_name, tun->dev->name); 1700 return 0; 1701 1702 err_detach: 1703 tun_detach_all(dev); 1704 err_free_flow: 1705 tun_flow_uninit(tun); 1706 security_tun_dev_free_security(tun->security); 1707 err_free_dev: 1708 free_netdev(dev); 1709 return err; 1710 } 1711 1712 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1713 struct ifreq *ifr) 1714 { 1715 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1716 1717 strcpy(ifr->ifr_name, tun->dev->name); 1718 1719 ifr->ifr_flags = tun_flags(tun); 1720 1721 } 1722 1723 /* This is like a cut-down ethtool ops, except done via tun fd so no 1724 * privs required. */ 1725 static int set_offload(struct tun_struct *tun, unsigned long arg) 1726 { 1727 netdev_features_t features = 0; 1728 1729 if (arg & TUN_F_CSUM) { 1730 features |= NETIF_F_HW_CSUM; 1731 arg &= ~TUN_F_CSUM; 1732 1733 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1734 if (arg & TUN_F_TSO_ECN) { 1735 features |= NETIF_F_TSO_ECN; 1736 arg &= ~TUN_F_TSO_ECN; 1737 } 1738 if (arg & TUN_F_TSO4) 1739 features |= NETIF_F_TSO; 1740 if (arg & TUN_F_TSO6) 1741 features |= NETIF_F_TSO6; 1742 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1743 } 1744 1745 if (arg & TUN_F_UFO) { 1746 features |= NETIF_F_UFO; 1747 arg &= ~TUN_F_UFO; 1748 } 1749 } 1750 1751 /* This gives the user a way to test for new features in future by 1752 * trying to set them. */ 1753 if (arg) 1754 return -EINVAL; 1755 1756 tun->set_features = features; 1757 netdev_update_features(tun->dev); 1758 1759 return 0; 1760 } 1761 1762 static void tun_detach_filter(struct tun_struct *tun, int n) 1763 { 1764 int i; 1765 struct tun_file *tfile; 1766 1767 for (i = 0; i < n; i++) { 1768 tfile = rtnl_dereference(tun->tfiles[i]); 1769 sk_detach_filter(tfile->socket.sk); 1770 } 1771 1772 tun->filter_attached = false; 1773 } 1774 1775 static int tun_attach_filter(struct tun_struct *tun) 1776 { 1777 int i, ret = 0; 1778 struct tun_file *tfile; 1779 1780 for (i = 0; i < tun->numqueues; i++) { 1781 tfile = rtnl_dereference(tun->tfiles[i]); 1782 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1783 if (ret) { 1784 tun_detach_filter(tun, i); 1785 return ret; 1786 } 1787 } 1788 1789 tun->filter_attached = true; 1790 return ret; 1791 } 1792 1793 static void tun_set_sndbuf(struct tun_struct *tun) 1794 { 1795 struct tun_file *tfile; 1796 int i; 1797 1798 for (i = 0; i < tun->numqueues; i++) { 1799 tfile = rtnl_dereference(tun->tfiles[i]); 1800 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1801 } 1802 } 1803 1804 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1805 { 1806 struct tun_file *tfile = file->private_data; 1807 struct tun_struct *tun; 1808 int ret = 0; 1809 1810 rtnl_lock(); 1811 1812 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1813 tun = tfile->detached; 1814 if (!tun) { 1815 ret = -EINVAL; 1816 goto unlock; 1817 } 1818 ret = security_tun_dev_attach_queue(tun->security); 1819 if (ret < 0) 1820 goto unlock; 1821 ret = tun_attach(tun, file, false); 1822 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1823 tun = rtnl_dereference(tfile->tun); 1824 if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) 1825 ret = -EINVAL; 1826 else 1827 __tun_detach(tfile, false); 1828 } else 1829 ret = -EINVAL; 1830 1831 unlock: 1832 rtnl_unlock(); 1833 return ret; 1834 } 1835 1836 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1837 unsigned long arg, int ifreq_len) 1838 { 1839 struct tun_file *tfile = file->private_data; 1840 struct tun_struct *tun; 1841 void __user* argp = (void __user*)arg; 1842 struct ifreq ifr; 1843 kuid_t owner; 1844 kgid_t group; 1845 int sndbuf; 1846 int vnet_hdr_sz; 1847 unsigned int ifindex; 1848 int ret; 1849 1850 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1851 if (copy_from_user(&ifr, argp, ifreq_len)) 1852 return -EFAULT; 1853 } else { 1854 memset(&ifr, 0, sizeof(ifr)); 1855 } 1856 if (cmd == TUNGETFEATURES) { 1857 /* Currently this just means: "what IFF flags are valid?". 1858 * This is needed because we never checked for invalid flags on 1859 * TUNSETIFF. */ 1860 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | 1861 IFF_VNET_HDR | IFF_MULTI_QUEUE, 1862 (unsigned int __user*)argp); 1863 } else if (cmd == TUNSETQUEUE) 1864 return tun_set_queue(file, &ifr); 1865 1866 ret = 0; 1867 rtnl_lock(); 1868 1869 tun = __tun_get(tfile); 1870 if (cmd == TUNSETIFF && !tun) { 1871 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1872 1873 ret = tun_set_iff(tfile->net, file, &ifr); 1874 1875 if (ret) 1876 goto unlock; 1877 1878 if (copy_to_user(argp, &ifr, ifreq_len)) 1879 ret = -EFAULT; 1880 goto unlock; 1881 } 1882 if (cmd == TUNSETIFINDEX) { 1883 ret = -EPERM; 1884 if (tun) 1885 goto unlock; 1886 1887 ret = -EFAULT; 1888 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1889 goto unlock; 1890 1891 ret = 0; 1892 tfile->ifindex = ifindex; 1893 goto unlock; 1894 } 1895 1896 ret = -EBADFD; 1897 if (!tun) 1898 goto unlock; 1899 1900 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1901 1902 ret = 0; 1903 switch (cmd) { 1904 case TUNGETIFF: 1905 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1906 1907 if (tfile->detached) 1908 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1909 if (!tfile->socket.sk->sk_filter) 1910 ifr.ifr_flags |= IFF_NOFILTER; 1911 1912 if (copy_to_user(argp, &ifr, ifreq_len)) 1913 ret = -EFAULT; 1914 break; 1915 1916 case TUNSETNOCSUM: 1917 /* Disable/Enable checksum */ 1918 1919 /* [unimplemented] */ 1920 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1921 arg ? "disabled" : "enabled"); 1922 break; 1923 1924 case TUNSETPERSIST: 1925 /* Disable/Enable persist mode. Keep an extra reference to the 1926 * module to prevent the module being unprobed. 1927 */ 1928 if (arg && !(tun->flags & TUN_PERSIST)) { 1929 tun->flags |= TUN_PERSIST; 1930 __module_get(THIS_MODULE); 1931 } 1932 if (!arg && (tun->flags & TUN_PERSIST)) { 1933 tun->flags &= ~TUN_PERSIST; 1934 module_put(THIS_MODULE); 1935 } 1936 1937 tun_debug(KERN_INFO, tun, "persist %s\n", 1938 arg ? "enabled" : "disabled"); 1939 break; 1940 1941 case TUNSETOWNER: 1942 /* Set owner of the device */ 1943 owner = make_kuid(current_user_ns(), arg); 1944 if (!uid_valid(owner)) { 1945 ret = -EINVAL; 1946 break; 1947 } 1948 tun->owner = owner; 1949 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1950 from_kuid(&init_user_ns, tun->owner)); 1951 break; 1952 1953 case TUNSETGROUP: 1954 /* Set group of the device */ 1955 group = make_kgid(current_user_ns(), arg); 1956 if (!gid_valid(group)) { 1957 ret = -EINVAL; 1958 break; 1959 } 1960 tun->group = group; 1961 tun_debug(KERN_INFO, tun, "group set to %u\n", 1962 from_kgid(&init_user_ns, tun->group)); 1963 break; 1964 1965 case TUNSETLINK: 1966 /* Only allow setting the type when the interface is down */ 1967 if (tun->dev->flags & IFF_UP) { 1968 tun_debug(KERN_INFO, tun, 1969 "Linktype set failed because interface is up\n"); 1970 ret = -EBUSY; 1971 } else { 1972 tun->dev->type = (int) arg; 1973 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1974 tun->dev->type); 1975 ret = 0; 1976 } 1977 break; 1978 1979 #ifdef TUN_DEBUG 1980 case TUNSETDEBUG: 1981 tun->debug = arg; 1982 break; 1983 #endif 1984 case TUNSETOFFLOAD: 1985 ret = set_offload(tun, arg); 1986 break; 1987 1988 case TUNSETTXFILTER: 1989 /* Can be set only for TAPs */ 1990 ret = -EINVAL; 1991 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 1992 break; 1993 ret = update_filter(&tun->txflt, (void __user *)arg); 1994 break; 1995 1996 case SIOCGIFHWADDR: 1997 /* Get hw address */ 1998 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 1999 ifr.ifr_hwaddr.sa_family = tun->dev->type; 2000 if (copy_to_user(argp, &ifr, ifreq_len)) 2001 ret = -EFAULT; 2002 break; 2003 2004 case SIOCSIFHWADDR: 2005 /* Set hw address */ 2006 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 2007 ifr.ifr_hwaddr.sa_data); 2008 2009 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2010 break; 2011 2012 case TUNGETSNDBUF: 2013 sndbuf = tfile->socket.sk->sk_sndbuf; 2014 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2015 ret = -EFAULT; 2016 break; 2017 2018 case TUNSETSNDBUF: 2019 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2020 ret = -EFAULT; 2021 break; 2022 } 2023 2024 tun->sndbuf = sndbuf; 2025 tun_set_sndbuf(tun); 2026 break; 2027 2028 case TUNGETVNETHDRSZ: 2029 vnet_hdr_sz = tun->vnet_hdr_sz; 2030 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2031 ret = -EFAULT; 2032 break; 2033 2034 case TUNSETVNETHDRSZ: 2035 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2036 ret = -EFAULT; 2037 break; 2038 } 2039 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2040 ret = -EINVAL; 2041 break; 2042 } 2043 2044 tun->vnet_hdr_sz = vnet_hdr_sz; 2045 break; 2046 2047 case TUNATTACHFILTER: 2048 /* Can be set only for TAPs */ 2049 ret = -EINVAL; 2050 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2051 break; 2052 ret = -EFAULT; 2053 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2054 break; 2055 2056 ret = tun_attach_filter(tun); 2057 break; 2058 2059 case TUNDETACHFILTER: 2060 /* Can be set only for TAPs */ 2061 ret = -EINVAL; 2062 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2063 break; 2064 ret = 0; 2065 tun_detach_filter(tun, tun->numqueues); 2066 break; 2067 2068 case TUNGETFILTER: 2069 ret = -EINVAL; 2070 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2071 break; 2072 ret = -EFAULT; 2073 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2074 break; 2075 ret = 0; 2076 break; 2077 2078 default: 2079 ret = -EINVAL; 2080 break; 2081 } 2082 2083 unlock: 2084 rtnl_unlock(); 2085 if (tun) 2086 tun_put(tun); 2087 return ret; 2088 } 2089 2090 static long tun_chr_ioctl(struct file *file, 2091 unsigned int cmd, unsigned long arg) 2092 { 2093 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2094 } 2095 2096 #ifdef CONFIG_COMPAT 2097 static long tun_chr_compat_ioctl(struct file *file, 2098 unsigned int cmd, unsigned long arg) 2099 { 2100 switch (cmd) { 2101 case TUNSETIFF: 2102 case TUNGETIFF: 2103 case TUNSETTXFILTER: 2104 case TUNGETSNDBUF: 2105 case TUNSETSNDBUF: 2106 case SIOCGIFHWADDR: 2107 case SIOCSIFHWADDR: 2108 arg = (unsigned long)compat_ptr(arg); 2109 break; 2110 default: 2111 arg = (compat_ulong_t)arg; 2112 break; 2113 } 2114 2115 /* 2116 * compat_ifreq is shorter than ifreq, so we must not access beyond 2117 * the end of that structure. All fields that are used in this 2118 * driver are compatible though, we don't need to convert the 2119 * contents. 2120 */ 2121 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2122 } 2123 #endif /* CONFIG_COMPAT */ 2124 2125 static int tun_chr_fasync(int fd, struct file *file, int on) 2126 { 2127 struct tun_file *tfile = file->private_data; 2128 int ret; 2129 2130 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2131 goto out; 2132 2133 if (on) { 2134 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2135 if (ret) 2136 goto out; 2137 tfile->flags |= TUN_FASYNC; 2138 } else 2139 tfile->flags &= ~TUN_FASYNC; 2140 ret = 0; 2141 out: 2142 return ret; 2143 } 2144 2145 static int tun_chr_open(struct inode *inode, struct file * file) 2146 { 2147 struct tun_file *tfile; 2148 2149 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2150 2151 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2152 &tun_proto); 2153 if (!tfile) 2154 return -ENOMEM; 2155 rcu_assign_pointer(tfile->tun, NULL); 2156 tfile->net = get_net(current->nsproxy->net_ns); 2157 tfile->flags = 0; 2158 tfile->ifindex = 0; 2159 2160 rcu_assign_pointer(tfile->socket.wq, &tfile->wq); 2161 init_waitqueue_head(&tfile->wq.wait); 2162 2163 tfile->socket.file = file; 2164 tfile->socket.ops = &tun_socket_ops; 2165 2166 sock_init_data(&tfile->socket, &tfile->sk); 2167 sk_change_net(&tfile->sk, tfile->net); 2168 2169 tfile->sk.sk_write_space = tun_sock_write_space; 2170 tfile->sk.sk_sndbuf = INT_MAX; 2171 2172 file->private_data = tfile; 2173 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2174 INIT_LIST_HEAD(&tfile->next); 2175 2176 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2177 2178 return 0; 2179 } 2180 2181 static int tun_chr_close(struct inode *inode, struct file *file) 2182 { 2183 struct tun_file *tfile = file->private_data; 2184 struct net *net = tfile->net; 2185 2186 tun_detach(tfile, true); 2187 put_net(net); 2188 2189 return 0; 2190 } 2191 2192 static const struct file_operations tun_fops = { 2193 .owner = THIS_MODULE, 2194 .llseek = no_llseek, 2195 .read = do_sync_read, 2196 .aio_read = tun_chr_aio_read, 2197 .write = do_sync_write, 2198 .aio_write = tun_chr_aio_write, 2199 .poll = tun_chr_poll, 2200 .unlocked_ioctl = tun_chr_ioctl, 2201 #ifdef CONFIG_COMPAT 2202 .compat_ioctl = tun_chr_compat_ioctl, 2203 #endif 2204 .open = tun_chr_open, 2205 .release = tun_chr_close, 2206 .fasync = tun_chr_fasync 2207 }; 2208 2209 static struct miscdevice tun_miscdev = { 2210 .minor = TUN_MINOR, 2211 .name = "tun", 2212 .nodename = "net/tun", 2213 .fops = &tun_fops, 2214 }; 2215 2216 /* ethtool interface */ 2217 2218 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2219 { 2220 cmd->supported = 0; 2221 cmd->advertising = 0; 2222 ethtool_cmd_speed_set(cmd, SPEED_10); 2223 cmd->duplex = DUPLEX_FULL; 2224 cmd->port = PORT_TP; 2225 cmd->phy_address = 0; 2226 cmd->transceiver = XCVR_INTERNAL; 2227 cmd->autoneg = AUTONEG_DISABLE; 2228 cmd->maxtxpkt = 0; 2229 cmd->maxrxpkt = 0; 2230 return 0; 2231 } 2232 2233 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2234 { 2235 struct tun_struct *tun = netdev_priv(dev); 2236 2237 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2238 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2239 2240 switch (tun->flags & TUN_TYPE_MASK) { 2241 case TUN_TUN_DEV: 2242 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2243 break; 2244 case TUN_TAP_DEV: 2245 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2246 break; 2247 } 2248 } 2249 2250 static u32 tun_get_msglevel(struct net_device *dev) 2251 { 2252 #ifdef TUN_DEBUG 2253 struct tun_struct *tun = netdev_priv(dev); 2254 return tun->debug; 2255 #else 2256 return -EOPNOTSUPP; 2257 #endif 2258 } 2259 2260 static void tun_set_msglevel(struct net_device *dev, u32 value) 2261 { 2262 #ifdef TUN_DEBUG 2263 struct tun_struct *tun = netdev_priv(dev); 2264 tun->debug = value; 2265 #endif 2266 } 2267 2268 static const struct ethtool_ops tun_ethtool_ops = { 2269 .get_settings = tun_get_settings, 2270 .get_drvinfo = tun_get_drvinfo, 2271 .get_msglevel = tun_get_msglevel, 2272 .set_msglevel = tun_set_msglevel, 2273 .get_link = ethtool_op_get_link, 2274 .get_ts_info = ethtool_op_get_ts_info, 2275 }; 2276 2277 2278 static int __init tun_init(void) 2279 { 2280 int ret = 0; 2281 2282 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2283 pr_info("%s\n", DRV_COPYRIGHT); 2284 2285 ret = rtnl_link_register(&tun_link_ops); 2286 if (ret) { 2287 pr_err("Can't register link_ops\n"); 2288 goto err_linkops; 2289 } 2290 2291 ret = misc_register(&tun_miscdev); 2292 if (ret) { 2293 pr_err("Can't register misc device %d\n", TUN_MINOR); 2294 goto err_misc; 2295 } 2296 return 0; 2297 err_misc: 2298 rtnl_link_unregister(&tun_link_ops); 2299 err_linkops: 2300 return ret; 2301 } 2302 2303 static void tun_cleanup(void) 2304 { 2305 misc_deregister(&tun_miscdev); 2306 rtnl_link_unregister(&tun_link_ops); 2307 } 2308 2309 /* Get an underlying socket object from tun file. Returns error unless file is 2310 * attached to a device. The returned object works like a packet socket, it 2311 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2312 * holding a reference to the file for as long as the socket is in use. */ 2313 struct socket *tun_get_socket(struct file *file) 2314 { 2315 struct tun_file *tfile; 2316 if (file->f_op != &tun_fops) 2317 return ERR_PTR(-EINVAL); 2318 tfile = file->private_data; 2319 if (!tfile) 2320 return ERR_PTR(-EBADFD); 2321 return &tfile->socket; 2322 } 2323 EXPORT_SYMBOL_GPL(tun_get_socket); 2324 2325 module_init(tun_init); 2326 module_exit(tun_cleanup); 2327 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2328 MODULE_AUTHOR(DRV_COPYRIGHT); 2329 MODULE_LICENSE("GPL"); 2330 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2331 MODULE_ALIAS("devname:net/tun"); 2332