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 offset = 0; 985 int copylen; 986 bool zerocopy = false; 987 int err; 988 u32 rxhash; 989 990 if (!(tun->flags & TUN_NO_PI)) { 991 if (len < sizeof(pi)) 992 return -EINVAL; 993 len -= sizeof(pi); 994 995 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) 996 return -EFAULT; 997 offset += sizeof(pi); 998 } 999 1000 if (tun->flags & TUN_VNET_HDR) { 1001 if (len < tun->vnet_hdr_sz) 1002 return -EINVAL; 1003 len -= tun->vnet_hdr_sz; 1004 1005 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) 1006 return -EFAULT; 1007 1008 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1009 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) 1010 gso.hdr_len = gso.csum_start + gso.csum_offset + 2; 1011 1012 if (gso.hdr_len > len) 1013 return -EINVAL; 1014 offset += tun->vnet_hdr_sz; 1015 } 1016 1017 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { 1018 align += NET_IP_ALIGN; 1019 if (unlikely(len < ETH_HLEN || 1020 (gso.hdr_len && gso.hdr_len < ETH_HLEN))) 1021 return -EINVAL; 1022 } 1023 1024 if (msg_control) { 1025 /* There are 256 bytes to be copied in skb, so there is 1026 * enough room for skb expand head in case it is used. 1027 * The rest of the buffer is mapped from userspace. 1028 */ 1029 copylen = gso.hdr_len ? gso.hdr_len : GOODCOPY_LEN; 1030 linear = copylen; 1031 if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS) 1032 zerocopy = true; 1033 } 1034 1035 if (!zerocopy) { 1036 copylen = len; 1037 linear = gso.hdr_len; 1038 } 1039 1040 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1041 if (IS_ERR(skb)) { 1042 if (PTR_ERR(skb) != -EAGAIN) 1043 tun->dev->stats.rx_dropped++; 1044 return PTR_ERR(skb); 1045 } 1046 1047 if (zerocopy) 1048 err = zerocopy_sg_from_iovec(skb, iv, offset, count); 1049 else { 1050 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len); 1051 if (!err && msg_control) { 1052 struct ubuf_info *uarg = msg_control; 1053 uarg->callback(uarg, false); 1054 } 1055 } 1056 1057 if (err) { 1058 tun->dev->stats.rx_dropped++; 1059 kfree_skb(skb); 1060 return -EFAULT; 1061 } 1062 1063 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1064 if (!skb_partial_csum_set(skb, gso.csum_start, 1065 gso.csum_offset)) { 1066 tun->dev->stats.rx_frame_errors++; 1067 kfree_skb(skb); 1068 return -EINVAL; 1069 } 1070 } 1071 1072 switch (tun->flags & TUN_TYPE_MASK) { 1073 case TUN_TUN_DEV: 1074 if (tun->flags & TUN_NO_PI) { 1075 switch (skb->data[0] & 0xf0) { 1076 case 0x40: 1077 pi.proto = htons(ETH_P_IP); 1078 break; 1079 case 0x60: 1080 pi.proto = htons(ETH_P_IPV6); 1081 break; 1082 default: 1083 tun->dev->stats.rx_dropped++; 1084 kfree_skb(skb); 1085 return -EINVAL; 1086 } 1087 } 1088 1089 skb_reset_mac_header(skb); 1090 skb->protocol = pi.proto; 1091 skb->dev = tun->dev; 1092 break; 1093 case TUN_TAP_DEV: 1094 skb->protocol = eth_type_trans(skb, tun->dev); 1095 break; 1096 } 1097 1098 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1099 pr_debug("GSO!\n"); 1100 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1101 case VIRTIO_NET_HDR_GSO_TCPV4: 1102 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1103 break; 1104 case VIRTIO_NET_HDR_GSO_TCPV6: 1105 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1106 break; 1107 case VIRTIO_NET_HDR_GSO_UDP: 1108 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1109 break; 1110 default: 1111 tun->dev->stats.rx_frame_errors++; 1112 kfree_skb(skb); 1113 return -EINVAL; 1114 } 1115 1116 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1117 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1118 1119 skb_shinfo(skb)->gso_size = gso.gso_size; 1120 if (skb_shinfo(skb)->gso_size == 0) { 1121 tun->dev->stats.rx_frame_errors++; 1122 kfree_skb(skb); 1123 return -EINVAL; 1124 } 1125 1126 /* Header must be checked, and gso_segs computed. */ 1127 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1128 skb_shinfo(skb)->gso_segs = 0; 1129 } 1130 1131 /* copy skb_ubuf_info for callback when skb has no error */ 1132 if (zerocopy) { 1133 skb_shinfo(skb)->destructor_arg = msg_control; 1134 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1135 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1136 } 1137 1138 skb_reset_network_header(skb); 1139 skb_probe_transport_header(skb, 0); 1140 1141 rxhash = skb_get_rxhash(skb); 1142 netif_rx_ni(skb); 1143 1144 tun->dev->stats.rx_packets++; 1145 tun->dev->stats.rx_bytes += len; 1146 1147 tun_flow_update(tun, rxhash, tfile); 1148 return total_len; 1149 } 1150 1151 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 1152 unsigned long count, loff_t pos) 1153 { 1154 struct file *file = iocb->ki_filp; 1155 struct tun_struct *tun = tun_get(file); 1156 struct tun_file *tfile = file->private_data; 1157 ssize_t result; 1158 1159 if (!tun) 1160 return -EBADFD; 1161 1162 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count); 1163 1164 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count), 1165 count, file->f_flags & O_NONBLOCK); 1166 1167 tun_put(tun); 1168 return result; 1169 } 1170 1171 /* Put packet to the user space buffer */ 1172 static ssize_t tun_put_user(struct tun_struct *tun, 1173 struct tun_file *tfile, 1174 struct sk_buff *skb, 1175 const struct iovec *iv, int len) 1176 { 1177 struct tun_pi pi = { 0, skb->protocol }; 1178 ssize_t total = 0; 1179 int vlan_offset = 0; 1180 1181 if (!(tun->flags & TUN_NO_PI)) { 1182 if ((len -= sizeof(pi)) < 0) 1183 return -EINVAL; 1184 1185 if (len < skb->len) { 1186 /* Packet will be striped */ 1187 pi.flags |= TUN_PKT_STRIP; 1188 } 1189 1190 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi))) 1191 return -EFAULT; 1192 total += sizeof(pi); 1193 } 1194 1195 if (tun->flags & TUN_VNET_HDR) { 1196 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1197 if ((len -= tun->vnet_hdr_sz) < 0) 1198 return -EINVAL; 1199 1200 if (skb_is_gso(skb)) { 1201 struct skb_shared_info *sinfo = skb_shinfo(skb); 1202 1203 /* This is a hint as to how much should be linear. */ 1204 gso.hdr_len = skb_headlen(skb); 1205 gso.gso_size = sinfo->gso_size; 1206 if (sinfo->gso_type & SKB_GSO_TCPV4) 1207 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1208 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1209 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1210 else if (sinfo->gso_type & SKB_GSO_UDP) 1211 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1212 else { 1213 pr_err("unexpected GSO type: " 1214 "0x%x, gso_size %d, hdr_len %d\n", 1215 sinfo->gso_type, gso.gso_size, 1216 gso.hdr_len); 1217 print_hex_dump(KERN_ERR, "tun: ", 1218 DUMP_PREFIX_NONE, 1219 16, 1, skb->head, 1220 min((int)gso.hdr_len, 64), true); 1221 WARN_ON_ONCE(1); 1222 return -EINVAL; 1223 } 1224 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1225 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1226 } else 1227 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1228 1229 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1230 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1231 gso.csum_start = skb_checksum_start_offset(skb); 1232 gso.csum_offset = skb->csum_offset; 1233 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1234 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1235 } /* else everything is zero */ 1236 1237 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, 1238 sizeof(gso)))) 1239 return -EFAULT; 1240 total += tun->vnet_hdr_sz; 1241 } 1242 1243 if (!vlan_tx_tag_present(skb)) { 1244 len = min_t(int, skb->len, len); 1245 } else { 1246 int copy, ret; 1247 struct { 1248 __be16 h_vlan_proto; 1249 __be16 h_vlan_TCI; 1250 } veth; 1251 1252 veth.h_vlan_proto = skb->vlan_proto; 1253 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 1254 1255 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1256 len = min_t(int, skb->len + VLAN_HLEN, len); 1257 1258 copy = min_t(int, vlan_offset, len); 1259 ret = skb_copy_datagram_const_iovec(skb, 0, iv, total, copy); 1260 len -= copy; 1261 total += copy; 1262 if (ret || !len) 1263 goto done; 1264 1265 copy = min_t(int, sizeof(veth), len); 1266 ret = memcpy_toiovecend(iv, (void *)&veth, total, copy); 1267 len -= copy; 1268 total += copy; 1269 if (ret || !len) 1270 goto done; 1271 } 1272 1273 skb_copy_datagram_const_iovec(skb, vlan_offset, iv, total, len); 1274 total += len; 1275 1276 done: 1277 tun->dev->stats.tx_packets++; 1278 tun->dev->stats.tx_bytes += len; 1279 1280 return total; 1281 } 1282 1283 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1284 struct kiocb *iocb, const struct iovec *iv, 1285 ssize_t len, int noblock) 1286 { 1287 DECLARE_WAITQUEUE(wait, current); 1288 struct sk_buff *skb; 1289 ssize_t ret = 0; 1290 1291 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1292 1293 if (unlikely(!noblock)) 1294 add_wait_queue(&tfile->wq.wait, &wait); 1295 while (len) { 1296 if (unlikely(!noblock)) 1297 current->state = TASK_INTERRUPTIBLE; 1298 1299 /* Read frames from the queue */ 1300 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) { 1301 if (noblock) { 1302 ret = -EAGAIN; 1303 break; 1304 } 1305 if (signal_pending(current)) { 1306 ret = -ERESTARTSYS; 1307 break; 1308 } 1309 if (tun->dev->reg_state != NETREG_REGISTERED) { 1310 ret = -EIO; 1311 break; 1312 } 1313 1314 /* Nothing to read, let's sleep */ 1315 schedule(); 1316 continue; 1317 } 1318 1319 ret = tun_put_user(tun, tfile, skb, iv, len); 1320 kfree_skb(skb); 1321 break; 1322 } 1323 1324 if (unlikely(!noblock)) { 1325 current->state = TASK_RUNNING; 1326 remove_wait_queue(&tfile->wq.wait, &wait); 1327 } 1328 1329 return ret; 1330 } 1331 1332 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 1333 unsigned long count, loff_t pos) 1334 { 1335 struct file *file = iocb->ki_filp; 1336 struct tun_file *tfile = file->private_data; 1337 struct tun_struct *tun = __tun_get(tfile); 1338 ssize_t len, ret; 1339 1340 if (!tun) 1341 return -EBADFD; 1342 len = iov_length(iv, count); 1343 if (len < 0) { 1344 ret = -EINVAL; 1345 goto out; 1346 } 1347 1348 ret = tun_do_read(tun, tfile, iocb, iv, len, 1349 file->f_flags & O_NONBLOCK); 1350 ret = min_t(ssize_t, ret, len); 1351 out: 1352 tun_put(tun); 1353 return ret; 1354 } 1355 1356 static void tun_free_netdev(struct net_device *dev) 1357 { 1358 struct tun_struct *tun = netdev_priv(dev); 1359 1360 BUG_ON(!(list_empty(&tun->disabled))); 1361 tun_flow_uninit(tun); 1362 security_tun_dev_free_security(tun->security); 1363 free_netdev(dev); 1364 } 1365 1366 static void tun_setup(struct net_device *dev) 1367 { 1368 struct tun_struct *tun = netdev_priv(dev); 1369 1370 tun->owner = INVALID_UID; 1371 tun->group = INVALID_GID; 1372 1373 dev->ethtool_ops = &tun_ethtool_ops; 1374 dev->destructor = tun_free_netdev; 1375 } 1376 1377 /* Trivial set of netlink ops to allow deleting tun or tap 1378 * device with netlink. 1379 */ 1380 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1381 { 1382 return -EINVAL; 1383 } 1384 1385 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1386 .kind = DRV_NAME, 1387 .priv_size = sizeof(struct tun_struct), 1388 .setup = tun_setup, 1389 .validate = tun_validate, 1390 }; 1391 1392 static void tun_sock_write_space(struct sock *sk) 1393 { 1394 struct tun_file *tfile; 1395 wait_queue_head_t *wqueue; 1396 1397 if (!sock_writeable(sk)) 1398 return; 1399 1400 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1401 return; 1402 1403 wqueue = sk_sleep(sk); 1404 if (wqueue && waitqueue_active(wqueue)) 1405 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1406 POLLWRNORM | POLLWRBAND); 1407 1408 tfile = container_of(sk, struct tun_file, sk); 1409 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1410 } 1411 1412 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1413 struct msghdr *m, size_t total_len) 1414 { 1415 int ret; 1416 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1417 struct tun_struct *tun = __tun_get(tfile); 1418 1419 if (!tun) 1420 return -EBADFD; 1421 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len, 1422 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); 1423 tun_put(tun); 1424 return ret; 1425 } 1426 1427 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1428 struct msghdr *m, size_t total_len, 1429 int flags) 1430 { 1431 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1432 struct tun_struct *tun = __tun_get(tfile); 1433 int ret; 1434 1435 if (!tun) 1436 return -EBADFD; 1437 1438 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1439 ret = -EINVAL; 1440 goto out; 1441 } 1442 if (flags & MSG_ERRQUEUE) { 1443 ret = sock_recv_errqueue(sock->sk, m, total_len, 1444 SOL_PACKET, TUN_TX_TIMESTAMP); 1445 goto out; 1446 } 1447 ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len, 1448 flags & MSG_DONTWAIT); 1449 if (ret > total_len) { 1450 m->msg_flags |= MSG_TRUNC; 1451 ret = flags & MSG_TRUNC ? ret : total_len; 1452 } 1453 out: 1454 tun_put(tun); 1455 return ret; 1456 } 1457 1458 static int tun_release(struct socket *sock) 1459 { 1460 if (sock->sk) 1461 sock_put(sock->sk); 1462 return 0; 1463 } 1464 1465 /* Ops structure to mimic raw sockets with tun */ 1466 static const struct proto_ops tun_socket_ops = { 1467 .sendmsg = tun_sendmsg, 1468 .recvmsg = tun_recvmsg, 1469 .release = tun_release, 1470 }; 1471 1472 static struct proto tun_proto = { 1473 .name = "tun", 1474 .owner = THIS_MODULE, 1475 .obj_size = sizeof(struct tun_file), 1476 }; 1477 1478 static int tun_flags(struct tun_struct *tun) 1479 { 1480 int flags = 0; 1481 1482 if (tun->flags & TUN_TUN_DEV) 1483 flags |= IFF_TUN; 1484 else 1485 flags |= IFF_TAP; 1486 1487 if (tun->flags & TUN_NO_PI) 1488 flags |= IFF_NO_PI; 1489 1490 /* This flag has no real effect. We track the value for backwards 1491 * compatibility. 1492 */ 1493 if (tun->flags & TUN_ONE_QUEUE) 1494 flags |= IFF_ONE_QUEUE; 1495 1496 if (tun->flags & TUN_VNET_HDR) 1497 flags |= IFF_VNET_HDR; 1498 1499 if (tun->flags & TUN_TAP_MQ) 1500 flags |= IFF_MULTI_QUEUE; 1501 1502 if (tun->flags & TUN_PERSIST) 1503 flags |= IFF_PERSIST; 1504 1505 return flags; 1506 } 1507 1508 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1509 char *buf) 1510 { 1511 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1512 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1513 } 1514 1515 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1516 char *buf) 1517 { 1518 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1519 return uid_valid(tun->owner)? 1520 sprintf(buf, "%u\n", 1521 from_kuid_munged(current_user_ns(), tun->owner)): 1522 sprintf(buf, "-1\n"); 1523 } 1524 1525 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1526 char *buf) 1527 { 1528 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1529 return gid_valid(tun->group) ? 1530 sprintf(buf, "%u\n", 1531 from_kgid_munged(current_user_ns(), tun->group)): 1532 sprintf(buf, "-1\n"); 1533 } 1534 1535 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1536 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1537 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1538 1539 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1540 { 1541 struct tun_struct *tun; 1542 struct tun_file *tfile = file->private_data; 1543 struct net_device *dev; 1544 int err; 1545 1546 if (tfile->detached) 1547 return -EINVAL; 1548 1549 dev = __dev_get_by_name(net, ifr->ifr_name); 1550 if (dev) { 1551 if (ifr->ifr_flags & IFF_TUN_EXCL) 1552 return -EBUSY; 1553 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1554 tun = netdev_priv(dev); 1555 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1556 tun = netdev_priv(dev); 1557 else 1558 return -EINVAL; 1559 1560 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1561 !!(tun->flags & TUN_TAP_MQ)) 1562 return -EINVAL; 1563 1564 if (tun_not_capable(tun)) 1565 return -EPERM; 1566 err = security_tun_dev_open(tun->security); 1567 if (err < 0) 1568 return err; 1569 1570 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1571 if (err < 0) 1572 return err; 1573 1574 if (tun->flags & TUN_TAP_MQ && 1575 (tun->numqueues + tun->numdisabled > 1)) { 1576 /* One or more queue has already been attached, no need 1577 * to initialize the device again. 1578 */ 1579 return 0; 1580 } 1581 } 1582 else { 1583 char *name; 1584 unsigned long flags = 0; 1585 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1586 MAX_TAP_QUEUES : 1; 1587 1588 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1589 return -EPERM; 1590 err = security_tun_dev_create(); 1591 if (err < 0) 1592 return err; 1593 1594 /* Set dev type */ 1595 if (ifr->ifr_flags & IFF_TUN) { 1596 /* TUN device */ 1597 flags |= TUN_TUN_DEV; 1598 name = "tun%d"; 1599 } else if (ifr->ifr_flags & IFF_TAP) { 1600 /* TAP device */ 1601 flags |= TUN_TAP_DEV; 1602 name = "tap%d"; 1603 } else 1604 return -EINVAL; 1605 1606 if (*ifr->ifr_name) 1607 name = ifr->ifr_name; 1608 1609 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1610 tun_setup, queues, queues); 1611 1612 if (!dev) 1613 return -ENOMEM; 1614 1615 dev_net_set(dev, net); 1616 dev->rtnl_link_ops = &tun_link_ops; 1617 dev->ifindex = tfile->ifindex; 1618 1619 tun = netdev_priv(dev); 1620 tun->dev = dev; 1621 tun->flags = flags; 1622 tun->txflt.count = 0; 1623 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1624 1625 tun->filter_attached = false; 1626 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1627 1628 spin_lock_init(&tun->lock); 1629 1630 err = security_tun_dev_alloc_security(&tun->security); 1631 if (err < 0) 1632 goto err_free_dev; 1633 1634 tun_net_init(dev); 1635 tun_flow_init(tun); 1636 1637 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1638 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1639 NETIF_F_HW_VLAN_STAG_TX; 1640 dev->features = dev->hw_features; 1641 dev->vlan_features = dev->features; 1642 1643 INIT_LIST_HEAD(&tun->disabled); 1644 err = tun_attach(tun, file, false); 1645 if (err < 0) 1646 goto err_free_flow; 1647 1648 err = register_netdevice(tun->dev); 1649 if (err < 0) 1650 goto err_detach; 1651 1652 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1653 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1654 device_create_file(&tun->dev->dev, &dev_attr_group)) 1655 pr_err("Failed to create tun sysfs files\n"); 1656 } 1657 1658 netif_carrier_on(tun->dev); 1659 1660 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1661 1662 if (ifr->ifr_flags & IFF_NO_PI) 1663 tun->flags |= TUN_NO_PI; 1664 else 1665 tun->flags &= ~TUN_NO_PI; 1666 1667 /* This flag has no real effect. We track the value for backwards 1668 * compatibility. 1669 */ 1670 if (ifr->ifr_flags & IFF_ONE_QUEUE) 1671 tun->flags |= TUN_ONE_QUEUE; 1672 else 1673 tun->flags &= ~TUN_ONE_QUEUE; 1674 1675 if (ifr->ifr_flags & IFF_VNET_HDR) 1676 tun->flags |= TUN_VNET_HDR; 1677 else 1678 tun->flags &= ~TUN_VNET_HDR; 1679 1680 if (ifr->ifr_flags & IFF_MULTI_QUEUE) 1681 tun->flags |= TUN_TAP_MQ; 1682 else 1683 tun->flags &= ~TUN_TAP_MQ; 1684 1685 /* Make sure persistent devices do not get stuck in 1686 * xoff state. 1687 */ 1688 if (netif_running(tun->dev)) 1689 netif_tx_wake_all_queues(tun->dev); 1690 1691 strcpy(ifr->ifr_name, tun->dev->name); 1692 return 0; 1693 1694 err_detach: 1695 tun_detach_all(dev); 1696 err_free_flow: 1697 tun_flow_uninit(tun); 1698 security_tun_dev_free_security(tun->security); 1699 err_free_dev: 1700 free_netdev(dev); 1701 return err; 1702 } 1703 1704 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1705 struct ifreq *ifr) 1706 { 1707 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1708 1709 strcpy(ifr->ifr_name, tun->dev->name); 1710 1711 ifr->ifr_flags = tun_flags(tun); 1712 1713 } 1714 1715 /* This is like a cut-down ethtool ops, except done via tun fd so no 1716 * privs required. */ 1717 static int set_offload(struct tun_struct *tun, unsigned long arg) 1718 { 1719 netdev_features_t features = 0; 1720 1721 if (arg & TUN_F_CSUM) { 1722 features |= NETIF_F_HW_CSUM; 1723 arg &= ~TUN_F_CSUM; 1724 1725 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1726 if (arg & TUN_F_TSO_ECN) { 1727 features |= NETIF_F_TSO_ECN; 1728 arg &= ~TUN_F_TSO_ECN; 1729 } 1730 if (arg & TUN_F_TSO4) 1731 features |= NETIF_F_TSO; 1732 if (arg & TUN_F_TSO6) 1733 features |= NETIF_F_TSO6; 1734 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1735 } 1736 1737 if (arg & TUN_F_UFO) { 1738 features |= NETIF_F_UFO; 1739 arg &= ~TUN_F_UFO; 1740 } 1741 } 1742 1743 /* This gives the user a way to test for new features in future by 1744 * trying to set them. */ 1745 if (arg) 1746 return -EINVAL; 1747 1748 tun->set_features = features; 1749 netdev_update_features(tun->dev); 1750 1751 return 0; 1752 } 1753 1754 static void tun_detach_filter(struct tun_struct *tun, int n) 1755 { 1756 int i; 1757 struct tun_file *tfile; 1758 1759 for (i = 0; i < n; i++) { 1760 tfile = rtnl_dereference(tun->tfiles[i]); 1761 sk_detach_filter(tfile->socket.sk); 1762 } 1763 1764 tun->filter_attached = false; 1765 } 1766 1767 static int tun_attach_filter(struct tun_struct *tun) 1768 { 1769 int i, ret = 0; 1770 struct tun_file *tfile; 1771 1772 for (i = 0; i < tun->numqueues; i++) { 1773 tfile = rtnl_dereference(tun->tfiles[i]); 1774 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1775 if (ret) { 1776 tun_detach_filter(tun, i); 1777 return ret; 1778 } 1779 } 1780 1781 tun->filter_attached = true; 1782 return ret; 1783 } 1784 1785 static void tun_set_sndbuf(struct tun_struct *tun) 1786 { 1787 struct tun_file *tfile; 1788 int i; 1789 1790 for (i = 0; i < tun->numqueues; i++) { 1791 tfile = rtnl_dereference(tun->tfiles[i]); 1792 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1793 } 1794 } 1795 1796 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1797 { 1798 struct tun_file *tfile = file->private_data; 1799 struct tun_struct *tun; 1800 int ret = 0; 1801 1802 rtnl_lock(); 1803 1804 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1805 tun = tfile->detached; 1806 if (!tun) { 1807 ret = -EINVAL; 1808 goto unlock; 1809 } 1810 ret = security_tun_dev_attach_queue(tun->security); 1811 if (ret < 0) 1812 goto unlock; 1813 ret = tun_attach(tun, file, false); 1814 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1815 tun = rtnl_dereference(tfile->tun); 1816 if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) 1817 ret = -EINVAL; 1818 else 1819 __tun_detach(tfile, false); 1820 } else 1821 ret = -EINVAL; 1822 1823 unlock: 1824 rtnl_unlock(); 1825 return ret; 1826 } 1827 1828 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1829 unsigned long arg, int ifreq_len) 1830 { 1831 struct tun_file *tfile = file->private_data; 1832 struct tun_struct *tun; 1833 void __user* argp = (void __user*)arg; 1834 struct ifreq ifr; 1835 kuid_t owner; 1836 kgid_t group; 1837 int sndbuf; 1838 int vnet_hdr_sz; 1839 unsigned int ifindex; 1840 int ret; 1841 1842 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1843 if (copy_from_user(&ifr, argp, ifreq_len)) 1844 return -EFAULT; 1845 } else { 1846 memset(&ifr, 0, sizeof(ifr)); 1847 } 1848 if (cmd == TUNGETFEATURES) { 1849 /* Currently this just means: "what IFF flags are valid?". 1850 * This is needed because we never checked for invalid flags on 1851 * TUNSETIFF. */ 1852 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | 1853 IFF_VNET_HDR | IFF_MULTI_QUEUE, 1854 (unsigned int __user*)argp); 1855 } else if (cmd == TUNSETQUEUE) 1856 return tun_set_queue(file, &ifr); 1857 1858 ret = 0; 1859 rtnl_lock(); 1860 1861 tun = __tun_get(tfile); 1862 if (cmd == TUNSETIFF && !tun) { 1863 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1864 1865 ret = tun_set_iff(tfile->net, file, &ifr); 1866 1867 if (ret) 1868 goto unlock; 1869 1870 if (copy_to_user(argp, &ifr, ifreq_len)) 1871 ret = -EFAULT; 1872 goto unlock; 1873 } 1874 if (cmd == TUNSETIFINDEX) { 1875 ret = -EPERM; 1876 if (tun) 1877 goto unlock; 1878 1879 ret = -EFAULT; 1880 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1881 goto unlock; 1882 1883 ret = 0; 1884 tfile->ifindex = ifindex; 1885 goto unlock; 1886 } 1887 1888 ret = -EBADFD; 1889 if (!tun) 1890 goto unlock; 1891 1892 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1893 1894 ret = 0; 1895 switch (cmd) { 1896 case TUNGETIFF: 1897 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1898 1899 if (tfile->detached) 1900 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1901 if (!tfile->socket.sk->sk_filter) 1902 ifr.ifr_flags |= IFF_NOFILTER; 1903 1904 if (copy_to_user(argp, &ifr, ifreq_len)) 1905 ret = -EFAULT; 1906 break; 1907 1908 case TUNSETNOCSUM: 1909 /* Disable/Enable checksum */ 1910 1911 /* [unimplemented] */ 1912 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1913 arg ? "disabled" : "enabled"); 1914 break; 1915 1916 case TUNSETPERSIST: 1917 /* Disable/Enable persist mode. Keep an extra reference to the 1918 * module to prevent the module being unprobed. 1919 */ 1920 if (arg && !(tun->flags & TUN_PERSIST)) { 1921 tun->flags |= TUN_PERSIST; 1922 __module_get(THIS_MODULE); 1923 } 1924 if (!arg && (tun->flags & TUN_PERSIST)) { 1925 tun->flags &= ~TUN_PERSIST; 1926 module_put(THIS_MODULE); 1927 } 1928 1929 tun_debug(KERN_INFO, tun, "persist %s\n", 1930 arg ? "enabled" : "disabled"); 1931 break; 1932 1933 case TUNSETOWNER: 1934 /* Set owner of the device */ 1935 owner = make_kuid(current_user_ns(), arg); 1936 if (!uid_valid(owner)) { 1937 ret = -EINVAL; 1938 break; 1939 } 1940 tun->owner = owner; 1941 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1942 from_kuid(&init_user_ns, tun->owner)); 1943 break; 1944 1945 case TUNSETGROUP: 1946 /* Set group of the device */ 1947 group = make_kgid(current_user_ns(), arg); 1948 if (!gid_valid(group)) { 1949 ret = -EINVAL; 1950 break; 1951 } 1952 tun->group = group; 1953 tun_debug(KERN_INFO, tun, "group set to %u\n", 1954 from_kgid(&init_user_ns, tun->group)); 1955 break; 1956 1957 case TUNSETLINK: 1958 /* Only allow setting the type when the interface is down */ 1959 if (tun->dev->flags & IFF_UP) { 1960 tun_debug(KERN_INFO, tun, 1961 "Linktype set failed because interface is up\n"); 1962 ret = -EBUSY; 1963 } else { 1964 tun->dev->type = (int) arg; 1965 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1966 tun->dev->type); 1967 ret = 0; 1968 } 1969 break; 1970 1971 #ifdef TUN_DEBUG 1972 case TUNSETDEBUG: 1973 tun->debug = arg; 1974 break; 1975 #endif 1976 case TUNSETOFFLOAD: 1977 ret = set_offload(tun, arg); 1978 break; 1979 1980 case TUNSETTXFILTER: 1981 /* Can be set only for TAPs */ 1982 ret = -EINVAL; 1983 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 1984 break; 1985 ret = update_filter(&tun->txflt, (void __user *)arg); 1986 break; 1987 1988 case SIOCGIFHWADDR: 1989 /* Get hw address */ 1990 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 1991 ifr.ifr_hwaddr.sa_family = tun->dev->type; 1992 if (copy_to_user(argp, &ifr, ifreq_len)) 1993 ret = -EFAULT; 1994 break; 1995 1996 case SIOCSIFHWADDR: 1997 /* Set hw address */ 1998 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 1999 ifr.ifr_hwaddr.sa_data); 2000 2001 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2002 break; 2003 2004 case TUNGETSNDBUF: 2005 sndbuf = tfile->socket.sk->sk_sndbuf; 2006 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2007 ret = -EFAULT; 2008 break; 2009 2010 case TUNSETSNDBUF: 2011 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2012 ret = -EFAULT; 2013 break; 2014 } 2015 2016 tun->sndbuf = sndbuf; 2017 tun_set_sndbuf(tun); 2018 break; 2019 2020 case TUNGETVNETHDRSZ: 2021 vnet_hdr_sz = tun->vnet_hdr_sz; 2022 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2023 ret = -EFAULT; 2024 break; 2025 2026 case TUNSETVNETHDRSZ: 2027 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2028 ret = -EFAULT; 2029 break; 2030 } 2031 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2032 ret = -EINVAL; 2033 break; 2034 } 2035 2036 tun->vnet_hdr_sz = vnet_hdr_sz; 2037 break; 2038 2039 case TUNATTACHFILTER: 2040 /* Can be set only for TAPs */ 2041 ret = -EINVAL; 2042 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2043 break; 2044 ret = -EFAULT; 2045 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2046 break; 2047 2048 ret = tun_attach_filter(tun); 2049 break; 2050 2051 case TUNDETACHFILTER: 2052 /* Can be set only for TAPs */ 2053 ret = -EINVAL; 2054 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2055 break; 2056 ret = 0; 2057 tun_detach_filter(tun, tun->numqueues); 2058 break; 2059 2060 case TUNGETFILTER: 2061 ret = -EINVAL; 2062 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2063 break; 2064 ret = -EFAULT; 2065 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2066 break; 2067 ret = 0; 2068 break; 2069 2070 default: 2071 ret = -EINVAL; 2072 break; 2073 } 2074 2075 unlock: 2076 rtnl_unlock(); 2077 if (tun) 2078 tun_put(tun); 2079 return ret; 2080 } 2081 2082 static long tun_chr_ioctl(struct file *file, 2083 unsigned int cmd, unsigned long arg) 2084 { 2085 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2086 } 2087 2088 #ifdef CONFIG_COMPAT 2089 static long tun_chr_compat_ioctl(struct file *file, 2090 unsigned int cmd, unsigned long arg) 2091 { 2092 switch (cmd) { 2093 case TUNSETIFF: 2094 case TUNGETIFF: 2095 case TUNSETTXFILTER: 2096 case TUNGETSNDBUF: 2097 case TUNSETSNDBUF: 2098 case SIOCGIFHWADDR: 2099 case SIOCSIFHWADDR: 2100 arg = (unsigned long)compat_ptr(arg); 2101 break; 2102 default: 2103 arg = (compat_ulong_t)arg; 2104 break; 2105 } 2106 2107 /* 2108 * compat_ifreq is shorter than ifreq, so we must not access beyond 2109 * the end of that structure. All fields that are used in this 2110 * driver are compatible though, we don't need to convert the 2111 * contents. 2112 */ 2113 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2114 } 2115 #endif /* CONFIG_COMPAT */ 2116 2117 static int tun_chr_fasync(int fd, struct file *file, int on) 2118 { 2119 struct tun_file *tfile = file->private_data; 2120 int ret; 2121 2122 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2123 goto out; 2124 2125 if (on) { 2126 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2127 if (ret) 2128 goto out; 2129 tfile->flags |= TUN_FASYNC; 2130 } else 2131 tfile->flags &= ~TUN_FASYNC; 2132 ret = 0; 2133 out: 2134 return ret; 2135 } 2136 2137 static int tun_chr_open(struct inode *inode, struct file * file) 2138 { 2139 struct tun_file *tfile; 2140 2141 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2142 2143 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2144 &tun_proto); 2145 if (!tfile) 2146 return -ENOMEM; 2147 rcu_assign_pointer(tfile->tun, NULL); 2148 tfile->net = get_net(current->nsproxy->net_ns); 2149 tfile->flags = 0; 2150 tfile->ifindex = 0; 2151 2152 rcu_assign_pointer(tfile->socket.wq, &tfile->wq); 2153 init_waitqueue_head(&tfile->wq.wait); 2154 2155 tfile->socket.file = file; 2156 tfile->socket.ops = &tun_socket_ops; 2157 2158 sock_init_data(&tfile->socket, &tfile->sk); 2159 sk_change_net(&tfile->sk, tfile->net); 2160 2161 tfile->sk.sk_write_space = tun_sock_write_space; 2162 tfile->sk.sk_sndbuf = INT_MAX; 2163 2164 file->private_data = tfile; 2165 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2166 INIT_LIST_HEAD(&tfile->next); 2167 2168 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2169 2170 return 0; 2171 } 2172 2173 static int tun_chr_close(struct inode *inode, struct file *file) 2174 { 2175 struct tun_file *tfile = file->private_data; 2176 struct net *net = tfile->net; 2177 2178 tun_detach(tfile, true); 2179 put_net(net); 2180 2181 return 0; 2182 } 2183 2184 static const struct file_operations tun_fops = { 2185 .owner = THIS_MODULE, 2186 .llseek = no_llseek, 2187 .read = do_sync_read, 2188 .aio_read = tun_chr_aio_read, 2189 .write = do_sync_write, 2190 .aio_write = tun_chr_aio_write, 2191 .poll = tun_chr_poll, 2192 .unlocked_ioctl = tun_chr_ioctl, 2193 #ifdef CONFIG_COMPAT 2194 .compat_ioctl = tun_chr_compat_ioctl, 2195 #endif 2196 .open = tun_chr_open, 2197 .release = tun_chr_close, 2198 .fasync = tun_chr_fasync 2199 }; 2200 2201 static struct miscdevice tun_miscdev = { 2202 .minor = TUN_MINOR, 2203 .name = "tun", 2204 .nodename = "net/tun", 2205 .fops = &tun_fops, 2206 }; 2207 2208 /* ethtool interface */ 2209 2210 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2211 { 2212 cmd->supported = 0; 2213 cmd->advertising = 0; 2214 ethtool_cmd_speed_set(cmd, SPEED_10); 2215 cmd->duplex = DUPLEX_FULL; 2216 cmd->port = PORT_TP; 2217 cmd->phy_address = 0; 2218 cmd->transceiver = XCVR_INTERNAL; 2219 cmd->autoneg = AUTONEG_DISABLE; 2220 cmd->maxtxpkt = 0; 2221 cmd->maxrxpkt = 0; 2222 return 0; 2223 } 2224 2225 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2226 { 2227 struct tun_struct *tun = netdev_priv(dev); 2228 2229 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2230 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2231 2232 switch (tun->flags & TUN_TYPE_MASK) { 2233 case TUN_TUN_DEV: 2234 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2235 break; 2236 case TUN_TAP_DEV: 2237 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2238 break; 2239 } 2240 } 2241 2242 static u32 tun_get_msglevel(struct net_device *dev) 2243 { 2244 #ifdef TUN_DEBUG 2245 struct tun_struct *tun = netdev_priv(dev); 2246 return tun->debug; 2247 #else 2248 return -EOPNOTSUPP; 2249 #endif 2250 } 2251 2252 static void tun_set_msglevel(struct net_device *dev, u32 value) 2253 { 2254 #ifdef TUN_DEBUG 2255 struct tun_struct *tun = netdev_priv(dev); 2256 tun->debug = value; 2257 #endif 2258 } 2259 2260 static const struct ethtool_ops tun_ethtool_ops = { 2261 .get_settings = tun_get_settings, 2262 .get_drvinfo = tun_get_drvinfo, 2263 .get_msglevel = tun_get_msglevel, 2264 .set_msglevel = tun_set_msglevel, 2265 .get_link = ethtool_op_get_link, 2266 .get_ts_info = ethtool_op_get_ts_info, 2267 }; 2268 2269 2270 static int __init tun_init(void) 2271 { 2272 int ret = 0; 2273 2274 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2275 pr_info("%s\n", DRV_COPYRIGHT); 2276 2277 ret = rtnl_link_register(&tun_link_ops); 2278 if (ret) { 2279 pr_err("Can't register link_ops\n"); 2280 goto err_linkops; 2281 } 2282 2283 ret = misc_register(&tun_miscdev); 2284 if (ret) { 2285 pr_err("Can't register misc device %d\n", TUN_MINOR); 2286 goto err_misc; 2287 } 2288 return 0; 2289 err_misc: 2290 rtnl_link_unregister(&tun_link_ops); 2291 err_linkops: 2292 return ret; 2293 } 2294 2295 static void tun_cleanup(void) 2296 { 2297 misc_deregister(&tun_miscdev); 2298 rtnl_link_unregister(&tun_link_ops); 2299 } 2300 2301 /* Get an underlying socket object from tun file. Returns error unless file is 2302 * attached to a device. The returned object works like a packet socket, it 2303 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2304 * holding a reference to the file for as long as the socket is in use. */ 2305 struct socket *tun_get_socket(struct file *file) 2306 { 2307 struct tun_file *tfile; 2308 if (file->f_op != &tun_fops) 2309 return ERR_PTR(-EINVAL); 2310 tfile = file->private_data; 2311 if (!tfile) 2312 return ERR_PTR(-EBADFD); 2313 return &tfile->socket; 2314 } 2315 EXPORT_SYMBOL_GPL(tun_get_socket); 2316 2317 module_init(tun_init); 2318 module_exit(tun_cleanup); 2319 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2320 MODULE_AUTHOR(DRV_COPYRIGHT); 2321 MODULE_LICENSE("GPL"); 2322 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2323 MODULE_ALIAS("devname:net/tun"); 2324