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 current->state = TASK_INTERRUPTIBLE; 1297 1298 /* Read frames from the queue */ 1299 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) { 1300 if (noblock) { 1301 ret = -EAGAIN; 1302 break; 1303 } 1304 if (signal_pending(current)) { 1305 ret = -ERESTARTSYS; 1306 break; 1307 } 1308 if (tun->dev->reg_state != NETREG_REGISTERED) { 1309 ret = -EIO; 1310 break; 1311 } 1312 1313 /* Nothing to read, let's sleep */ 1314 schedule(); 1315 continue; 1316 } 1317 1318 ret = tun_put_user(tun, tfile, skb, iv, len); 1319 kfree_skb(skb); 1320 break; 1321 } 1322 1323 current->state = TASK_RUNNING; 1324 if (unlikely(!noblock)) 1325 remove_wait_queue(&tfile->wq.wait, &wait); 1326 1327 return ret; 1328 } 1329 1330 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 1331 unsigned long count, loff_t pos) 1332 { 1333 struct file *file = iocb->ki_filp; 1334 struct tun_file *tfile = file->private_data; 1335 struct tun_struct *tun = __tun_get(tfile); 1336 ssize_t len, ret; 1337 1338 if (!tun) 1339 return -EBADFD; 1340 len = iov_length(iv, count); 1341 if (len < 0) { 1342 ret = -EINVAL; 1343 goto out; 1344 } 1345 1346 ret = tun_do_read(tun, tfile, iocb, iv, len, 1347 file->f_flags & O_NONBLOCK); 1348 ret = min_t(ssize_t, ret, len); 1349 out: 1350 tun_put(tun); 1351 return ret; 1352 } 1353 1354 static void tun_free_netdev(struct net_device *dev) 1355 { 1356 struct tun_struct *tun = netdev_priv(dev); 1357 1358 BUG_ON(!(list_empty(&tun->disabled))); 1359 tun_flow_uninit(tun); 1360 security_tun_dev_free_security(tun->security); 1361 free_netdev(dev); 1362 } 1363 1364 static void tun_setup(struct net_device *dev) 1365 { 1366 struct tun_struct *tun = netdev_priv(dev); 1367 1368 tun->owner = INVALID_UID; 1369 tun->group = INVALID_GID; 1370 1371 dev->ethtool_ops = &tun_ethtool_ops; 1372 dev->destructor = tun_free_netdev; 1373 } 1374 1375 /* Trivial set of netlink ops to allow deleting tun or tap 1376 * device with netlink. 1377 */ 1378 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1379 { 1380 return -EINVAL; 1381 } 1382 1383 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1384 .kind = DRV_NAME, 1385 .priv_size = sizeof(struct tun_struct), 1386 .setup = tun_setup, 1387 .validate = tun_validate, 1388 }; 1389 1390 static void tun_sock_write_space(struct sock *sk) 1391 { 1392 struct tun_file *tfile; 1393 wait_queue_head_t *wqueue; 1394 1395 if (!sock_writeable(sk)) 1396 return; 1397 1398 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1399 return; 1400 1401 wqueue = sk_sleep(sk); 1402 if (wqueue && waitqueue_active(wqueue)) 1403 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1404 POLLWRNORM | POLLWRBAND); 1405 1406 tfile = container_of(sk, struct tun_file, sk); 1407 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1408 } 1409 1410 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1411 struct msghdr *m, size_t total_len) 1412 { 1413 int ret; 1414 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1415 struct tun_struct *tun = __tun_get(tfile); 1416 1417 if (!tun) 1418 return -EBADFD; 1419 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len, 1420 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); 1421 tun_put(tun); 1422 return ret; 1423 } 1424 1425 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1426 struct msghdr *m, size_t total_len, 1427 int flags) 1428 { 1429 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1430 struct tun_struct *tun = __tun_get(tfile); 1431 int ret; 1432 1433 if (!tun) 1434 return -EBADFD; 1435 1436 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1437 ret = -EINVAL; 1438 goto out; 1439 } 1440 if (flags & MSG_ERRQUEUE) { 1441 ret = sock_recv_errqueue(sock->sk, m, total_len, 1442 SOL_PACKET, TUN_TX_TIMESTAMP); 1443 goto out; 1444 } 1445 ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len, 1446 flags & MSG_DONTWAIT); 1447 if (ret > total_len) { 1448 m->msg_flags |= MSG_TRUNC; 1449 ret = flags & MSG_TRUNC ? ret : total_len; 1450 } 1451 out: 1452 tun_put(tun); 1453 return ret; 1454 } 1455 1456 static int tun_release(struct socket *sock) 1457 { 1458 if (sock->sk) 1459 sock_put(sock->sk); 1460 return 0; 1461 } 1462 1463 /* Ops structure to mimic raw sockets with tun */ 1464 static const struct proto_ops tun_socket_ops = { 1465 .sendmsg = tun_sendmsg, 1466 .recvmsg = tun_recvmsg, 1467 .release = tun_release, 1468 }; 1469 1470 static struct proto tun_proto = { 1471 .name = "tun", 1472 .owner = THIS_MODULE, 1473 .obj_size = sizeof(struct tun_file), 1474 }; 1475 1476 static int tun_flags(struct tun_struct *tun) 1477 { 1478 int flags = 0; 1479 1480 if (tun->flags & TUN_TUN_DEV) 1481 flags |= IFF_TUN; 1482 else 1483 flags |= IFF_TAP; 1484 1485 if (tun->flags & TUN_NO_PI) 1486 flags |= IFF_NO_PI; 1487 1488 /* This flag has no real effect. We track the value for backwards 1489 * compatibility. 1490 */ 1491 if (tun->flags & TUN_ONE_QUEUE) 1492 flags |= IFF_ONE_QUEUE; 1493 1494 if (tun->flags & TUN_VNET_HDR) 1495 flags |= IFF_VNET_HDR; 1496 1497 if (tun->flags & TUN_TAP_MQ) 1498 flags |= IFF_MULTI_QUEUE; 1499 1500 if (tun->flags & TUN_PERSIST) 1501 flags |= IFF_PERSIST; 1502 1503 return flags; 1504 } 1505 1506 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1507 char *buf) 1508 { 1509 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1510 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1511 } 1512 1513 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1514 char *buf) 1515 { 1516 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1517 return uid_valid(tun->owner)? 1518 sprintf(buf, "%u\n", 1519 from_kuid_munged(current_user_ns(), tun->owner)): 1520 sprintf(buf, "-1\n"); 1521 } 1522 1523 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1524 char *buf) 1525 { 1526 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1527 return gid_valid(tun->group) ? 1528 sprintf(buf, "%u\n", 1529 from_kgid_munged(current_user_ns(), tun->group)): 1530 sprintf(buf, "-1\n"); 1531 } 1532 1533 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1534 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1535 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1536 1537 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1538 { 1539 struct tun_struct *tun; 1540 struct tun_file *tfile = file->private_data; 1541 struct net_device *dev; 1542 int err; 1543 1544 if (tfile->detached) 1545 return -EINVAL; 1546 1547 dev = __dev_get_by_name(net, ifr->ifr_name); 1548 if (dev) { 1549 if (ifr->ifr_flags & IFF_TUN_EXCL) 1550 return -EBUSY; 1551 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1552 tun = netdev_priv(dev); 1553 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1554 tun = netdev_priv(dev); 1555 else 1556 return -EINVAL; 1557 1558 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1559 !!(tun->flags & TUN_TAP_MQ)) 1560 return -EINVAL; 1561 1562 if (tun_not_capable(tun)) 1563 return -EPERM; 1564 err = security_tun_dev_open(tun->security); 1565 if (err < 0) 1566 return err; 1567 1568 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1569 if (err < 0) 1570 return err; 1571 1572 if (tun->flags & TUN_TAP_MQ && 1573 (tun->numqueues + tun->numdisabled > 1)) { 1574 /* One or more queue has already been attached, no need 1575 * to initialize the device again. 1576 */ 1577 return 0; 1578 } 1579 } 1580 else { 1581 char *name; 1582 unsigned long flags = 0; 1583 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1584 MAX_TAP_QUEUES : 1; 1585 1586 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1587 return -EPERM; 1588 err = security_tun_dev_create(); 1589 if (err < 0) 1590 return err; 1591 1592 /* Set dev type */ 1593 if (ifr->ifr_flags & IFF_TUN) { 1594 /* TUN device */ 1595 flags |= TUN_TUN_DEV; 1596 name = "tun%d"; 1597 } else if (ifr->ifr_flags & IFF_TAP) { 1598 /* TAP device */ 1599 flags |= TUN_TAP_DEV; 1600 name = "tap%d"; 1601 } else 1602 return -EINVAL; 1603 1604 if (*ifr->ifr_name) 1605 name = ifr->ifr_name; 1606 1607 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1608 tun_setup, queues, queues); 1609 1610 if (!dev) 1611 return -ENOMEM; 1612 1613 dev_net_set(dev, net); 1614 dev->rtnl_link_ops = &tun_link_ops; 1615 dev->ifindex = tfile->ifindex; 1616 1617 tun = netdev_priv(dev); 1618 tun->dev = dev; 1619 tun->flags = flags; 1620 tun->txflt.count = 0; 1621 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1622 1623 tun->filter_attached = false; 1624 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1625 1626 spin_lock_init(&tun->lock); 1627 1628 err = security_tun_dev_alloc_security(&tun->security); 1629 if (err < 0) 1630 goto err_free_dev; 1631 1632 tun_net_init(dev); 1633 tun_flow_init(tun); 1634 1635 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1636 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1637 NETIF_F_HW_VLAN_STAG_TX; 1638 dev->features = dev->hw_features; 1639 dev->vlan_features = dev->features; 1640 1641 INIT_LIST_HEAD(&tun->disabled); 1642 err = tun_attach(tun, file, false); 1643 if (err < 0) 1644 goto err_free_dev; 1645 1646 err = register_netdevice(tun->dev); 1647 if (err < 0) 1648 goto err_free_dev; 1649 1650 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1651 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1652 device_create_file(&tun->dev->dev, &dev_attr_group)) 1653 pr_err("Failed to create tun sysfs files\n"); 1654 } 1655 1656 netif_carrier_on(tun->dev); 1657 1658 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1659 1660 if (ifr->ifr_flags & IFF_NO_PI) 1661 tun->flags |= TUN_NO_PI; 1662 else 1663 tun->flags &= ~TUN_NO_PI; 1664 1665 /* This flag has no real effect. We track the value for backwards 1666 * compatibility. 1667 */ 1668 if (ifr->ifr_flags & IFF_ONE_QUEUE) 1669 tun->flags |= TUN_ONE_QUEUE; 1670 else 1671 tun->flags &= ~TUN_ONE_QUEUE; 1672 1673 if (ifr->ifr_flags & IFF_VNET_HDR) 1674 tun->flags |= TUN_VNET_HDR; 1675 else 1676 tun->flags &= ~TUN_VNET_HDR; 1677 1678 if (ifr->ifr_flags & IFF_MULTI_QUEUE) 1679 tun->flags |= TUN_TAP_MQ; 1680 else 1681 tun->flags &= ~TUN_TAP_MQ; 1682 1683 /* Make sure persistent devices do not get stuck in 1684 * xoff state. 1685 */ 1686 if (netif_running(tun->dev)) 1687 netif_tx_wake_all_queues(tun->dev); 1688 1689 strcpy(ifr->ifr_name, tun->dev->name); 1690 return 0; 1691 1692 err_free_dev: 1693 free_netdev(dev); 1694 return err; 1695 } 1696 1697 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1698 struct ifreq *ifr) 1699 { 1700 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1701 1702 strcpy(ifr->ifr_name, tun->dev->name); 1703 1704 ifr->ifr_flags = tun_flags(tun); 1705 1706 } 1707 1708 /* This is like a cut-down ethtool ops, except done via tun fd so no 1709 * privs required. */ 1710 static int set_offload(struct tun_struct *tun, unsigned long arg) 1711 { 1712 netdev_features_t features = 0; 1713 1714 if (arg & TUN_F_CSUM) { 1715 features |= NETIF_F_HW_CSUM; 1716 arg &= ~TUN_F_CSUM; 1717 1718 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1719 if (arg & TUN_F_TSO_ECN) { 1720 features |= NETIF_F_TSO_ECN; 1721 arg &= ~TUN_F_TSO_ECN; 1722 } 1723 if (arg & TUN_F_TSO4) 1724 features |= NETIF_F_TSO; 1725 if (arg & TUN_F_TSO6) 1726 features |= NETIF_F_TSO6; 1727 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1728 } 1729 1730 if (arg & TUN_F_UFO) { 1731 features |= NETIF_F_UFO; 1732 arg &= ~TUN_F_UFO; 1733 } 1734 } 1735 1736 /* This gives the user a way to test for new features in future by 1737 * trying to set them. */ 1738 if (arg) 1739 return -EINVAL; 1740 1741 tun->set_features = features; 1742 netdev_update_features(tun->dev); 1743 1744 return 0; 1745 } 1746 1747 static void tun_detach_filter(struct tun_struct *tun, int n) 1748 { 1749 int i; 1750 struct tun_file *tfile; 1751 1752 for (i = 0; i < n; i++) { 1753 tfile = rtnl_dereference(tun->tfiles[i]); 1754 sk_detach_filter(tfile->socket.sk); 1755 } 1756 1757 tun->filter_attached = false; 1758 } 1759 1760 static int tun_attach_filter(struct tun_struct *tun) 1761 { 1762 int i, ret = 0; 1763 struct tun_file *tfile; 1764 1765 for (i = 0; i < tun->numqueues; i++) { 1766 tfile = rtnl_dereference(tun->tfiles[i]); 1767 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1768 if (ret) { 1769 tun_detach_filter(tun, i); 1770 return ret; 1771 } 1772 } 1773 1774 tun->filter_attached = true; 1775 return ret; 1776 } 1777 1778 static void tun_set_sndbuf(struct tun_struct *tun) 1779 { 1780 struct tun_file *tfile; 1781 int i; 1782 1783 for (i = 0; i < tun->numqueues; i++) { 1784 tfile = rtnl_dereference(tun->tfiles[i]); 1785 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1786 } 1787 } 1788 1789 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1790 { 1791 struct tun_file *tfile = file->private_data; 1792 struct tun_struct *tun; 1793 int ret = 0; 1794 1795 rtnl_lock(); 1796 1797 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1798 tun = tfile->detached; 1799 if (!tun) { 1800 ret = -EINVAL; 1801 goto unlock; 1802 } 1803 ret = security_tun_dev_attach_queue(tun->security); 1804 if (ret < 0) 1805 goto unlock; 1806 ret = tun_attach(tun, file, false); 1807 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1808 tun = rtnl_dereference(tfile->tun); 1809 if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) 1810 ret = -EINVAL; 1811 else 1812 __tun_detach(tfile, false); 1813 } else 1814 ret = -EINVAL; 1815 1816 unlock: 1817 rtnl_unlock(); 1818 return ret; 1819 } 1820 1821 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1822 unsigned long arg, int ifreq_len) 1823 { 1824 struct tun_file *tfile = file->private_data; 1825 struct tun_struct *tun; 1826 void __user* argp = (void __user*)arg; 1827 struct ifreq ifr; 1828 kuid_t owner; 1829 kgid_t group; 1830 int sndbuf; 1831 int vnet_hdr_sz; 1832 unsigned int ifindex; 1833 int ret; 1834 1835 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1836 if (copy_from_user(&ifr, argp, ifreq_len)) 1837 return -EFAULT; 1838 } else { 1839 memset(&ifr, 0, sizeof(ifr)); 1840 } 1841 if (cmd == TUNGETFEATURES) { 1842 /* Currently this just means: "what IFF flags are valid?". 1843 * This is needed because we never checked for invalid flags on 1844 * TUNSETIFF. */ 1845 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | 1846 IFF_VNET_HDR | IFF_MULTI_QUEUE, 1847 (unsigned int __user*)argp); 1848 } else if (cmd == TUNSETQUEUE) 1849 return tun_set_queue(file, &ifr); 1850 1851 ret = 0; 1852 rtnl_lock(); 1853 1854 tun = __tun_get(tfile); 1855 if (cmd == TUNSETIFF && !tun) { 1856 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1857 1858 ret = tun_set_iff(tfile->net, file, &ifr); 1859 1860 if (ret) 1861 goto unlock; 1862 1863 if (copy_to_user(argp, &ifr, ifreq_len)) 1864 ret = -EFAULT; 1865 goto unlock; 1866 } 1867 if (cmd == TUNSETIFINDEX) { 1868 ret = -EPERM; 1869 if (tun) 1870 goto unlock; 1871 1872 ret = -EFAULT; 1873 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1874 goto unlock; 1875 1876 ret = 0; 1877 tfile->ifindex = ifindex; 1878 goto unlock; 1879 } 1880 1881 ret = -EBADFD; 1882 if (!tun) 1883 goto unlock; 1884 1885 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1886 1887 ret = 0; 1888 switch (cmd) { 1889 case TUNGETIFF: 1890 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1891 1892 if (tfile->detached) 1893 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1894 if (!tfile->socket.sk->sk_filter) 1895 ifr.ifr_flags |= IFF_NOFILTER; 1896 1897 if (copy_to_user(argp, &ifr, ifreq_len)) 1898 ret = -EFAULT; 1899 break; 1900 1901 case TUNSETNOCSUM: 1902 /* Disable/Enable checksum */ 1903 1904 /* [unimplemented] */ 1905 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1906 arg ? "disabled" : "enabled"); 1907 break; 1908 1909 case TUNSETPERSIST: 1910 /* Disable/Enable persist mode. Keep an extra reference to the 1911 * module to prevent the module being unprobed. 1912 */ 1913 if (arg && !(tun->flags & TUN_PERSIST)) { 1914 tun->flags |= TUN_PERSIST; 1915 __module_get(THIS_MODULE); 1916 } 1917 if (!arg && (tun->flags & TUN_PERSIST)) { 1918 tun->flags &= ~TUN_PERSIST; 1919 module_put(THIS_MODULE); 1920 } 1921 1922 tun_debug(KERN_INFO, tun, "persist %s\n", 1923 arg ? "enabled" : "disabled"); 1924 break; 1925 1926 case TUNSETOWNER: 1927 /* Set owner of the device */ 1928 owner = make_kuid(current_user_ns(), arg); 1929 if (!uid_valid(owner)) { 1930 ret = -EINVAL; 1931 break; 1932 } 1933 tun->owner = owner; 1934 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1935 from_kuid(&init_user_ns, tun->owner)); 1936 break; 1937 1938 case TUNSETGROUP: 1939 /* Set group of the device */ 1940 group = make_kgid(current_user_ns(), arg); 1941 if (!gid_valid(group)) { 1942 ret = -EINVAL; 1943 break; 1944 } 1945 tun->group = group; 1946 tun_debug(KERN_INFO, tun, "group set to %u\n", 1947 from_kgid(&init_user_ns, tun->group)); 1948 break; 1949 1950 case TUNSETLINK: 1951 /* Only allow setting the type when the interface is down */ 1952 if (tun->dev->flags & IFF_UP) { 1953 tun_debug(KERN_INFO, tun, 1954 "Linktype set failed because interface is up\n"); 1955 ret = -EBUSY; 1956 } else { 1957 tun->dev->type = (int) arg; 1958 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1959 tun->dev->type); 1960 ret = 0; 1961 } 1962 break; 1963 1964 #ifdef TUN_DEBUG 1965 case TUNSETDEBUG: 1966 tun->debug = arg; 1967 break; 1968 #endif 1969 case TUNSETOFFLOAD: 1970 ret = set_offload(tun, arg); 1971 break; 1972 1973 case TUNSETTXFILTER: 1974 /* Can be set only for TAPs */ 1975 ret = -EINVAL; 1976 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 1977 break; 1978 ret = update_filter(&tun->txflt, (void __user *)arg); 1979 break; 1980 1981 case SIOCGIFHWADDR: 1982 /* Get hw address */ 1983 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 1984 ifr.ifr_hwaddr.sa_family = tun->dev->type; 1985 if (copy_to_user(argp, &ifr, ifreq_len)) 1986 ret = -EFAULT; 1987 break; 1988 1989 case SIOCSIFHWADDR: 1990 /* Set hw address */ 1991 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 1992 ifr.ifr_hwaddr.sa_data); 1993 1994 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 1995 break; 1996 1997 case TUNGETSNDBUF: 1998 sndbuf = tfile->socket.sk->sk_sndbuf; 1999 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2000 ret = -EFAULT; 2001 break; 2002 2003 case TUNSETSNDBUF: 2004 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2005 ret = -EFAULT; 2006 break; 2007 } 2008 2009 tun->sndbuf = sndbuf; 2010 tun_set_sndbuf(tun); 2011 break; 2012 2013 case TUNGETVNETHDRSZ: 2014 vnet_hdr_sz = tun->vnet_hdr_sz; 2015 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2016 ret = -EFAULT; 2017 break; 2018 2019 case TUNSETVNETHDRSZ: 2020 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2021 ret = -EFAULT; 2022 break; 2023 } 2024 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2025 ret = -EINVAL; 2026 break; 2027 } 2028 2029 tun->vnet_hdr_sz = vnet_hdr_sz; 2030 break; 2031 2032 case TUNATTACHFILTER: 2033 /* Can be set only for TAPs */ 2034 ret = -EINVAL; 2035 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2036 break; 2037 ret = -EFAULT; 2038 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2039 break; 2040 2041 ret = tun_attach_filter(tun); 2042 break; 2043 2044 case TUNDETACHFILTER: 2045 /* Can be set only for TAPs */ 2046 ret = -EINVAL; 2047 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2048 break; 2049 ret = 0; 2050 tun_detach_filter(tun, tun->numqueues); 2051 break; 2052 2053 case TUNGETFILTER: 2054 ret = -EINVAL; 2055 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2056 break; 2057 ret = -EFAULT; 2058 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2059 break; 2060 ret = 0; 2061 break; 2062 2063 default: 2064 ret = -EINVAL; 2065 break; 2066 } 2067 2068 unlock: 2069 rtnl_unlock(); 2070 if (tun) 2071 tun_put(tun); 2072 return ret; 2073 } 2074 2075 static long tun_chr_ioctl(struct file *file, 2076 unsigned int cmd, unsigned long arg) 2077 { 2078 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2079 } 2080 2081 #ifdef CONFIG_COMPAT 2082 static long tun_chr_compat_ioctl(struct file *file, 2083 unsigned int cmd, unsigned long arg) 2084 { 2085 switch (cmd) { 2086 case TUNSETIFF: 2087 case TUNGETIFF: 2088 case TUNSETTXFILTER: 2089 case TUNGETSNDBUF: 2090 case TUNSETSNDBUF: 2091 case SIOCGIFHWADDR: 2092 case SIOCSIFHWADDR: 2093 arg = (unsigned long)compat_ptr(arg); 2094 break; 2095 default: 2096 arg = (compat_ulong_t)arg; 2097 break; 2098 } 2099 2100 /* 2101 * compat_ifreq is shorter than ifreq, so we must not access beyond 2102 * the end of that structure. All fields that are used in this 2103 * driver are compatible though, we don't need to convert the 2104 * contents. 2105 */ 2106 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2107 } 2108 #endif /* CONFIG_COMPAT */ 2109 2110 static int tun_chr_fasync(int fd, struct file *file, int on) 2111 { 2112 struct tun_file *tfile = file->private_data; 2113 int ret; 2114 2115 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2116 goto out; 2117 2118 if (on) { 2119 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2120 if (ret) 2121 goto out; 2122 tfile->flags |= TUN_FASYNC; 2123 } else 2124 tfile->flags &= ~TUN_FASYNC; 2125 ret = 0; 2126 out: 2127 return ret; 2128 } 2129 2130 static int tun_chr_open(struct inode *inode, struct file * file) 2131 { 2132 struct tun_file *tfile; 2133 2134 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2135 2136 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2137 &tun_proto); 2138 if (!tfile) 2139 return -ENOMEM; 2140 rcu_assign_pointer(tfile->tun, NULL); 2141 tfile->net = get_net(current->nsproxy->net_ns); 2142 tfile->flags = 0; 2143 tfile->ifindex = 0; 2144 2145 rcu_assign_pointer(tfile->socket.wq, &tfile->wq); 2146 init_waitqueue_head(&tfile->wq.wait); 2147 2148 tfile->socket.file = file; 2149 tfile->socket.ops = &tun_socket_ops; 2150 2151 sock_init_data(&tfile->socket, &tfile->sk); 2152 sk_change_net(&tfile->sk, tfile->net); 2153 2154 tfile->sk.sk_write_space = tun_sock_write_space; 2155 tfile->sk.sk_sndbuf = INT_MAX; 2156 2157 file->private_data = tfile; 2158 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2159 INIT_LIST_HEAD(&tfile->next); 2160 2161 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2162 2163 return 0; 2164 } 2165 2166 static int tun_chr_close(struct inode *inode, struct file *file) 2167 { 2168 struct tun_file *tfile = file->private_data; 2169 struct net *net = tfile->net; 2170 2171 tun_detach(tfile, true); 2172 put_net(net); 2173 2174 return 0; 2175 } 2176 2177 static const struct file_operations tun_fops = { 2178 .owner = THIS_MODULE, 2179 .llseek = no_llseek, 2180 .read = do_sync_read, 2181 .aio_read = tun_chr_aio_read, 2182 .write = do_sync_write, 2183 .aio_write = tun_chr_aio_write, 2184 .poll = tun_chr_poll, 2185 .unlocked_ioctl = tun_chr_ioctl, 2186 #ifdef CONFIG_COMPAT 2187 .compat_ioctl = tun_chr_compat_ioctl, 2188 #endif 2189 .open = tun_chr_open, 2190 .release = tun_chr_close, 2191 .fasync = tun_chr_fasync 2192 }; 2193 2194 static struct miscdevice tun_miscdev = { 2195 .minor = TUN_MINOR, 2196 .name = "tun", 2197 .nodename = "net/tun", 2198 .fops = &tun_fops, 2199 }; 2200 2201 /* ethtool interface */ 2202 2203 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2204 { 2205 cmd->supported = 0; 2206 cmd->advertising = 0; 2207 ethtool_cmd_speed_set(cmd, SPEED_10); 2208 cmd->duplex = DUPLEX_FULL; 2209 cmd->port = PORT_TP; 2210 cmd->phy_address = 0; 2211 cmd->transceiver = XCVR_INTERNAL; 2212 cmd->autoneg = AUTONEG_DISABLE; 2213 cmd->maxtxpkt = 0; 2214 cmd->maxrxpkt = 0; 2215 return 0; 2216 } 2217 2218 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2219 { 2220 struct tun_struct *tun = netdev_priv(dev); 2221 2222 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2223 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2224 2225 switch (tun->flags & TUN_TYPE_MASK) { 2226 case TUN_TUN_DEV: 2227 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2228 break; 2229 case TUN_TAP_DEV: 2230 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2231 break; 2232 } 2233 } 2234 2235 static u32 tun_get_msglevel(struct net_device *dev) 2236 { 2237 #ifdef TUN_DEBUG 2238 struct tun_struct *tun = netdev_priv(dev); 2239 return tun->debug; 2240 #else 2241 return -EOPNOTSUPP; 2242 #endif 2243 } 2244 2245 static void tun_set_msglevel(struct net_device *dev, u32 value) 2246 { 2247 #ifdef TUN_DEBUG 2248 struct tun_struct *tun = netdev_priv(dev); 2249 tun->debug = value; 2250 #endif 2251 } 2252 2253 static const struct ethtool_ops tun_ethtool_ops = { 2254 .get_settings = tun_get_settings, 2255 .get_drvinfo = tun_get_drvinfo, 2256 .get_msglevel = tun_get_msglevel, 2257 .set_msglevel = tun_set_msglevel, 2258 .get_link = ethtool_op_get_link, 2259 .get_ts_info = ethtool_op_get_ts_info, 2260 }; 2261 2262 2263 static int __init tun_init(void) 2264 { 2265 int ret = 0; 2266 2267 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2268 pr_info("%s\n", DRV_COPYRIGHT); 2269 2270 ret = rtnl_link_register(&tun_link_ops); 2271 if (ret) { 2272 pr_err("Can't register link_ops\n"); 2273 goto err_linkops; 2274 } 2275 2276 ret = misc_register(&tun_miscdev); 2277 if (ret) { 2278 pr_err("Can't register misc device %d\n", TUN_MINOR); 2279 goto err_misc; 2280 } 2281 return 0; 2282 err_misc: 2283 rtnl_link_unregister(&tun_link_ops); 2284 err_linkops: 2285 return ret; 2286 } 2287 2288 static void tun_cleanup(void) 2289 { 2290 misc_deregister(&tun_miscdev); 2291 rtnl_link_unregister(&tun_link_ops); 2292 } 2293 2294 /* Get an underlying socket object from tun file. Returns error unless file is 2295 * attached to a device. The returned object works like a packet socket, it 2296 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2297 * holding a reference to the file for as long as the socket is in use. */ 2298 struct socket *tun_get_socket(struct file *file) 2299 { 2300 struct tun_file *tfile; 2301 if (file->f_op != &tun_fops) 2302 return ERR_PTR(-EINVAL); 2303 tfile = file->private_data; 2304 if (!tfile) 2305 return ERR_PTR(-EBADFD); 2306 return &tfile->socket; 2307 } 2308 EXPORT_SYMBOL_GPL(tun_get_socket); 2309 2310 module_init(tun_init); 2311 module_exit(tun_cleanup); 2312 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2313 MODULE_AUTHOR(DRV_COPYRIGHT); 2314 MODULE_LICENSE("GPL"); 2315 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2316 MODULE_ALIAS("devname:net/tun"); 2317