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/crc32.h> 64 #include <linux/nsproxy.h> 65 #include <linux/virtio_net.h> 66 #include <linux/rcupdate.h> 67 #include <net/net_namespace.h> 68 #include <net/netns/generic.h> 69 #include <net/rtnetlink.h> 70 #include <net/sock.h> 71 72 #include <asm/uaccess.h> 73 74 /* Uncomment to enable debugging */ 75 /* #define TUN_DEBUG 1 */ 76 77 #ifdef TUN_DEBUG 78 static int debug; 79 80 #define tun_debug(level, tun, fmt, args...) \ 81 do { \ 82 if (tun->debug) \ 83 netdev_printk(level, tun->dev, fmt, ##args); \ 84 } while (0) 85 #define DBG1(level, fmt, args...) \ 86 do { \ 87 if (debug == 2) \ 88 printk(level fmt, ##args); \ 89 } while (0) 90 #else 91 #define tun_debug(level, tun, fmt, args...) \ 92 do { \ 93 if (0) \ 94 netdev_printk(level, tun->dev, fmt, ##args); \ 95 } while (0) 96 #define DBG1(level, fmt, args...) \ 97 do { \ 98 if (0) \ 99 printk(level fmt, ##args); \ 100 } while (0) 101 #endif 102 103 #define GOODCOPY_LEN 128 104 105 #define FLT_EXACT_COUNT 8 106 struct tap_filter { 107 unsigned int count; /* Number of addrs. Zero means disabled */ 108 u32 mask[2]; /* Mask of the hashed addrs */ 109 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 110 }; 111 112 /* DEFAULT_MAX_NUM_RSS_QUEUES were choosed to let the rx/tx queues allocated for 113 * the netdevice to be fit in one page. So we can make sure the success of 114 * memory allocation. TODO: increase the limit. */ 115 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES 116 #define MAX_TAP_FLOWS 4096 117 118 #define TUN_FLOW_EXPIRE (3 * HZ) 119 120 /* A tun_file connects an open character device to a tuntap netdevice. It 121 * also contains all socket related strctures (except sock_fprog and tap_filter) 122 * to serve as one transmit queue for tuntap device. The sock_fprog and 123 * tap_filter were kept in tun_struct since they were used for filtering for the 124 * netdevice not for a specific queue (at least I didn't see the requirement for 125 * this). 126 * 127 * RCU usage: 128 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 129 * other can only be read while rcu_read_lock or rtnl_lock is held. 130 */ 131 struct tun_file { 132 struct sock sk; 133 struct socket socket; 134 struct socket_wq wq; 135 struct tun_struct __rcu *tun; 136 struct net *net; 137 struct fasync_struct *fasync; 138 /* only used for fasnyc */ 139 unsigned int flags; 140 u16 queue_index; 141 struct list_head next; 142 struct tun_struct *detached; 143 }; 144 145 struct tun_flow_entry { 146 struct hlist_node hash_link; 147 struct rcu_head rcu; 148 struct tun_struct *tun; 149 150 u32 rxhash; 151 int queue_index; 152 unsigned long updated; 153 }; 154 155 #define TUN_NUM_FLOW_ENTRIES 1024 156 157 /* Since the socket were moved to tun_file, to preserve the behavior of persist 158 * device, socket filter, sndbuf and vnet header size were restore when the 159 * file were attached to a persist device. 160 */ 161 struct tun_struct { 162 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 163 unsigned int numqueues; 164 unsigned int flags; 165 kuid_t owner; 166 kgid_t group; 167 168 struct net_device *dev; 169 netdev_features_t set_features; 170 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 171 NETIF_F_TSO6|NETIF_F_UFO) 172 173 int vnet_hdr_sz; 174 int sndbuf; 175 struct tap_filter txflt; 176 struct sock_fprog fprog; 177 /* protected by rtnl lock */ 178 bool filter_attached; 179 #ifdef TUN_DEBUG 180 int debug; 181 #endif 182 spinlock_t lock; 183 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 184 struct timer_list flow_gc_timer; 185 unsigned long ageing_time; 186 unsigned int numdisabled; 187 struct list_head disabled; 188 void *security; 189 u32 flow_count; 190 }; 191 192 static inline u32 tun_hashfn(u32 rxhash) 193 { 194 return rxhash & 0x3ff; 195 } 196 197 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 198 { 199 struct tun_flow_entry *e; 200 201 hlist_for_each_entry_rcu(e, head, hash_link) { 202 if (e->rxhash == rxhash) 203 return e; 204 } 205 return NULL; 206 } 207 208 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 209 struct hlist_head *head, 210 u32 rxhash, u16 queue_index) 211 { 212 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 213 214 if (e) { 215 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 216 rxhash, queue_index); 217 e->updated = jiffies; 218 e->rxhash = rxhash; 219 e->queue_index = queue_index; 220 e->tun = tun; 221 hlist_add_head_rcu(&e->hash_link, head); 222 ++tun->flow_count; 223 } 224 return e; 225 } 226 227 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 228 { 229 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 230 e->rxhash, e->queue_index); 231 hlist_del_rcu(&e->hash_link); 232 kfree_rcu(e, rcu); 233 --tun->flow_count; 234 } 235 236 static void tun_flow_flush(struct tun_struct *tun) 237 { 238 int i; 239 240 spin_lock_bh(&tun->lock); 241 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 242 struct tun_flow_entry *e; 243 struct hlist_node *n; 244 245 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 246 tun_flow_delete(tun, e); 247 } 248 spin_unlock_bh(&tun->lock); 249 } 250 251 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 252 { 253 int i; 254 255 spin_lock_bh(&tun->lock); 256 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 257 struct tun_flow_entry *e; 258 struct hlist_node *n; 259 260 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 261 if (e->queue_index == queue_index) 262 tun_flow_delete(tun, e); 263 } 264 } 265 spin_unlock_bh(&tun->lock); 266 } 267 268 static void tun_flow_cleanup(unsigned long data) 269 { 270 struct tun_struct *tun = (struct tun_struct *)data; 271 unsigned long delay = tun->ageing_time; 272 unsigned long next_timer = jiffies + delay; 273 unsigned long count = 0; 274 int i; 275 276 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 277 278 spin_lock_bh(&tun->lock); 279 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 280 struct tun_flow_entry *e; 281 struct hlist_node *n; 282 283 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 284 unsigned long this_timer; 285 count++; 286 this_timer = e->updated + delay; 287 if (time_before_eq(this_timer, jiffies)) 288 tun_flow_delete(tun, e); 289 else if (time_before(this_timer, next_timer)) 290 next_timer = this_timer; 291 } 292 } 293 294 if (count) 295 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 296 spin_unlock_bh(&tun->lock); 297 } 298 299 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 300 struct tun_file *tfile) 301 { 302 struct hlist_head *head; 303 struct tun_flow_entry *e; 304 unsigned long delay = tun->ageing_time; 305 u16 queue_index = tfile->queue_index; 306 307 if (!rxhash) 308 return; 309 else 310 head = &tun->flows[tun_hashfn(rxhash)]; 311 312 rcu_read_lock(); 313 314 /* We may get a very small possibility of OOO during switching, not 315 * worth to optimize.*/ 316 if (tun->numqueues == 1 || tfile->detached) 317 goto unlock; 318 319 e = tun_flow_find(head, rxhash); 320 if (likely(e)) { 321 /* TODO: keep queueing to old queue until it's empty? */ 322 e->queue_index = queue_index; 323 e->updated = jiffies; 324 } else { 325 spin_lock_bh(&tun->lock); 326 if (!tun_flow_find(head, rxhash) && 327 tun->flow_count < MAX_TAP_FLOWS) 328 tun_flow_create(tun, head, rxhash, queue_index); 329 330 if (!timer_pending(&tun->flow_gc_timer)) 331 mod_timer(&tun->flow_gc_timer, 332 round_jiffies_up(jiffies + delay)); 333 spin_unlock_bh(&tun->lock); 334 } 335 336 unlock: 337 rcu_read_unlock(); 338 } 339 340 /* We try to identify a flow through its rxhash first. The reason that 341 * we do not check rxq no. is becuase some cards(e.g 82599), chooses 342 * the rxq based on the txq where the last packet of the flow comes. As 343 * the userspace application move between processors, we may get a 344 * different rxq no. here. If we could not get rxhash, then we would 345 * hope the rxq no. may help here. 346 */ 347 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb) 348 { 349 struct tun_struct *tun = netdev_priv(dev); 350 struct tun_flow_entry *e; 351 u32 txq = 0; 352 u32 numqueues = 0; 353 354 rcu_read_lock(); 355 numqueues = ACCESS_ONCE(tun->numqueues); 356 357 txq = skb_get_rxhash(skb); 358 if (txq) { 359 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 360 if (e) 361 txq = e->queue_index; 362 else 363 /* use multiply and shift instead of expensive divide */ 364 txq = ((u64)txq * numqueues) >> 32; 365 } else if (likely(skb_rx_queue_recorded(skb))) { 366 txq = skb_get_rx_queue(skb); 367 while (unlikely(txq >= numqueues)) 368 txq -= numqueues; 369 } 370 371 rcu_read_unlock(); 372 return txq; 373 } 374 375 static inline bool tun_not_capable(struct tun_struct *tun) 376 { 377 const struct cred *cred = current_cred(); 378 struct net *net = dev_net(tun->dev); 379 380 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 381 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 382 !ns_capable(net->user_ns, CAP_NET_ADMIN); 383 } 384 385 static void tun_set_real_num_queues(struct tun_struct *tun) 386 { 387 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 388 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 389 } 390 391 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 392 { 393 tfile->detached = tun; 394 list_add_tail(&tfile->next, &tun->disabled); 395 ++tun->numdisabled; 396 } 397 398 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 399 { 400 struct tun_struct *tun = tfile->detached; 401 402 tfile->detached = NULL; 403 list_del_init(&tfile->next); 404 --tun->numdisabled; 405 return tun; 406 } 407 408 static void __tun_detach(struct tun_file *tfile, bool clean) 409 { 410 struct tun_file *ntfile; 411 struct tun_struct *tun; 412 413 tun = rtnl_dereference(tfile->tun); 414 415 if (tun && !tfile->detached) { 416 u16 index = tfile->queue_index; 417 BUG_ON(index >= tun->numqueues); 418 419 rcu_assign_pointer(tun->tfiles[index], 420 tun->tfiles[tun->numqueues - 1]); 421 ntfile = rtnl_dereference(tun->tfiles[index]); 422 ntfile->queue_index = index; 423 424 --tun->numqueues; 425 if (clean) { 426 rcu_assign_pointer(tfile->tun, NULL); 427 sock_put(&tfile->sk); 428 } else 429 tun_disable_queue(tun, tfile); 430 431 synchronize_net(); 432 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 433 /* Drop read queue */ 434 skb_queue_purge(&tfile->sk.sk_receive_queue); 435 tun_set_real_num_queues(tun); 436 } else if (tfile->detached && clean) { 437 tun = tun_enable_queue(tfile); 438 sock_put(&tfile->sk); 439 } 440 441 if (clean) { 442 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 443 netif_carrier_off(tun->dev); 444 445 if (!(tun->flags & TUN_PERSIST) && 446 tun->dev->reg_state == NETREG_REGISTERED) 447 unregister_netdevice(tun->dev); 448 } 449 450 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 451 &tfile->socket.flags)); 452 sk_release_kernel(&tfile->sk); 453 } 454 } 455 456 static void tun_detach(struct tun_file *tfile, bool clean) 457 { 458 rtnl_lock(); 459 __tun_detach(tfile, clean); 460 rtnl_unlock(); 461 } 462 463 static void tun_detach_all(struct net_device *dev) 464 { 465 struct tun_struct *tun = netdev_priv(dev); 466 struct tun_file *tfile, *tmp; 467 int i, n = tun->numqueues; 468 469 for (i = 0; i < n; i++) { 470 tfile = rtnl_dereference(tun->tfiles[i]); 471 BUG_ON(!tfile); 472 wake_up_all(&tfile->wq.wait); 473 rcu_assign_pointer(tfile->tun, NULL); 474 --tun->numqueues; 475 } 476 list_for_each_entry(tfile, &tun->disabled, next) { 477 wake_up_all(&tfile->wq.wait); 478 rcu_assign_pointer(tfile->tun, NULL); 479 } 480 BUG_ON(tun->numqueues != 0); 481 482 synchronize_net(); 483 for (i = 0; i < n; i++) { 484 tfile = rtnl_dereference(tun->tfiles[i]); 485 /* Drop read queue */ 486 skb_queue_purge(&tfile->sk.sk_receive_queue); 487 sock_put(&tfile->sk); 488 } 489 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 490 tun_enable_queue(tfile); 491 skb_queue_purge(&tfile->sk.sk_receive_queue); 492 sock_put(&tfile->sk); 493 } 494 BUG_ON(tun->numdisabled != 0); 495 496 if (tun->flags & TUN_PERSIST) 497 module_put(THIS_MODULE); 498 } 499 500 static int tun_attach(struct tun_struct *tun, struct file *file) 501 { 502 struct tun_file *tfile = file->private_data; 503 int err; 504 505 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 506 if (err < 0) 507 goto out; 508 509 err = -EINVAL; 510 if (rtnl_dereference(tfile->tun) && !tfile->detached) 511 goto out; 512 513 err = -EBUSY; 514 if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1) 515 goto out; 516 517 err = -E2BIG; 518 if (!tfile->detached && 519 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 520 goto out; 521 522 err = 0; 523 524 /* Re-attach the filter to presist device */ 525 if (tun->filter_attached == true) { 526 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 527 if (!err) 528 goto out; 529 } 530 tfile->queue_index = tun->numqueues; 531 rcu_assign_pointer(tfile->tun, tun); 532 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 533 tun->numqueues++; 534 535 if (tfile->detached) 536 tun_enable_queue(tfile); 537 else 538 sock_hold(&tfile->sk); 539 540 tun_set_real_num_queues(tun); 541 542 /* device is allowed to go away first, so no need to hold extra 543 * refcnt. 544 */ 545 546 out: 547 return err; 548 } 549 550 static struct tun_struct *__tun_get(struct tun_file *tfile) 551 { 552 struct tun_struct *tun; 553 554 rcu_read_lock(); 555 tun = rcu_dereference(tfile->tun); 556 if (tun) 557 dev_hold(tun->dev); 558 rcu_read_unlock(); 559 560 return tun; 561 } 562 563 static struct tun_struct *tun_get(struct file *file) 564 { 565 return __tun_get(file->private_data); 566 } 567 568 static void tun_put(struct tun_struct *tun) 569 { 570 dev_put(tun->dev); 571 } 572 573 /* TAP filtering */ 574 static void addr_hash_set(u32 *mask, const u8 *addr) 575 { 576 int n = ether_crc(ETH_ALEN, addr) >> 26; 577 mask[n >> 5] |= (1 << (n & 31)); 578 } 579 580 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 581 { 582 int n = ether_crc(ETH_ALEN, addr) >> 26; 583 return mask[n >> 5] & (1 << (n & 31)); 584 } 585 586 static int update_filter(struct tap_filter *filter, void __user *arg) 587 { 588 struct { u8 u[ETH_ALEN]; } *addr; 589 struct tun_filter uf; 590 int err, alen, n, nexact; 591 592 if (copy_from_user(&uf, arg, sizeof(uf))) 593 return -EFAULT; 594 595 if (!uf.count) { 596 /* Disabled */ 597 filter->count = 0; 598 return 0; 599 } 600 601 alen = ETH_ALEN * uf.count; 602 addr = kmalloc(alen, GFP_KERNEL); 603 if (!addr) 604 return -ENOMEM; 605 606 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 607 err = -EFAULT; 608 goto done; 609 } 610 611 /* The filter is updated without holding any locks. Which is 612 * perfectly safe. We disable it first and in the worst 613 * case we'll accept a few undesired packets. */ 614 filter->count = 0; 615 wmb(); 616 617 /* Use first set of addresses as an exact filter */ 618 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 619 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 620 621 nexact = n; 622 623 /* Remaining multicast addresses are hashed, 624 * unicast will leave the filter disabled. */ 625 memset(filter->mask, 0, sizeof(filter->mask)); 626 for (; n < uf.count; n++) { 627 if (!is_multicast_ether_addr(addr[n].u)) { 628 err = 0; /* no filter */ 629 goto done; 630 } 631 addr_hash_set(filter->mask, addr[n].u); 632 } 633 634 /* For ALLMULTI just set the mask to all ones. 635 * This overrides the mask populated above. */ 636 if ((uf.flags & TUN_FLT_ALLMULTI)) 637 memset(filter->mask, ~0, sizeof(filter->mask)); 638 639 /* Now enable the filter */ 640 wmb(); 641 filter->count = nexact; 642 643 /* Return the number of exact filters */ 644 err = nexact; 645 646 done: 647 kfree(addr); 648 return err; 649 } 650 651 /* Returns: 0 - drop, !=0 - accept */ 652 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 653 { 654 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 655 * at this point. */ 656 struct ethhdr *eh = (struct ethhdr *) skb->data; 657 int i; 658 659 /* Exact match */ 660 for (i = 0; i < filter->count; i++) 661 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 662 return 1; 663 664 /* Inexact match (multicast only) */ 665 if (is_multicast_ether_addr(eh->h_dest)) 666 return addr_hash_test(filter->mask, eh->h_dest); 667 668 return 0; 669 } 670 671 /* 672 * Checks whether the packet is accepted or not. 673 * Returns: 0 - drop, !=0 - accept 674 */ 675 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 676 { 677 if (!filter->count) 678 return 1; 679 680 return run_filter(filter, skb); 681 } 682 683 /* Network device part of the driver */ 684 685 static const struct ethtool_ops tun_ethtool_ops; 686 687 /* Net device detach from fd. */ 688 static void tun_net_uninit(struct net_device *dev) 689 { 690 tun_detach_all(dev); 691 } 692 693 /* Net device open. */ 694 static int tun_net_open(struct net_device *dev) 695 { 696 netif_tx_start_all_queues(dev); 697 return 0; 698 } 699 700 /* Net device close. */ 701 static int tun_net_close(struct net_device *dev) 702 { 703 netif_tx_stop_all_queues(dev); 704 return 0; 705 } 706 707 /* Net device start xmit */ 708 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 709 { 710 struct tun_struct *tun = netdev_priv(dev); 711 int txq = skb->queue_mapping; 712 struct tun_file *tfile; 713 714 rcu_read_lock(); 715 tfile = rcu_dereference(tun->tfiles[txq]); 716 717 /* Drop packet if interface is not attached */ 718 if (txq >= tun->numqueues) 719 goto drop; 720 721 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 722 723 BUG_ON(!tfile); 724 725 /* Drop if the filter does not like it. 726 * This is a noop if the filter is disabled. 727 * Filter can be enabled only for the TAP devices. */ 728 if (!check_filter(&tun->txflt, skb)) 729 goto drop; 730 731 if (tfile->socket.sk->sk_filter && 732 sk_filter(tfile->socket.sk, skb)) 733 goto drop; 734 735 /* Limit the number of packets queued by dividing txq length with the 736 * number of queues. 737 */ 738 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) 739 >= dev->tx_queue_len / tun->numqueues) 740 goto drop; 741 742 /* Orphan the skb - required as we might hang on to it 743 * for indefinite time. */ 744 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 745 goto drop; 746 skb_orphan(skb); 747 748 nf_reset(skb); 749 750 /* Enqueue packet */ 751 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 752 753 /* Notify and wake up reader process */ 754 if (tfile->flags & TUN_FASYNC) 755 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 756 wake_up_interruptible_poll(&tfile->wq.wait, POLLIN | 757 POLLRDNORM | POLLRDBAND); 758 759 rcu_read_unlock(); 760 return NETDEV_TX_OK; 761 762 drop: 763 dev->stats.tx_dropped++; 764 skb_tx_error(skb); 765 kfree_skb(skb); 766 rcu_read_unlock(); 767 return NETDEV_TX_OK; 768 } 769 770 static void tun_net_mclist(struct net_device *dev) 771 { 772 /* 773 * This callback is supposed to deal with mc filter in 774 * _rx_ path and has nothing to do with the _tx_ path. 775 * In rx path we always accept everything userspace gives us. 776 */ 777 } 778 779 #define MIN_MTU 68 780 #define MAX_MTU 65535 781 782 static int 783 tun_net_change_mtu(struct net_device *dev, int new_mtu) 784 { 785 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 786 return -EINVAL; 787 dev->mtu = new_mtu; 788 return 0; 789 } 790 791 static netdev_features_t tun_net_fix_features(struct net_device *dev, 792 netdev_features_t features) 793 { 794 struct tun_struct *tun = netdev_priv(dev); 795 796 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 797 } 798 #ifdef CONFIG_NET_POLL_CONTROLLER 799 static void tun_poll_controller(struct net_device *dev) 800 { 801 /* 802 * Tun only receives frames when: 803 * 1) the char device endpoint gets data from user space 804 * 2) the tun socket gets a sendmsg call from user space 805 * Since both of those are syncronous operations, we are guaranteed 806 * never to have pending data when we poll for it 807 * so theres nothing to do here but return. 808 * We need this though so netpoll recognizes us as an interface that 809 * supports polling, which enables bridge devices in virt setups to 810 * still use netconsole 811 */ 812 return; 813 } 814 #endif 815 static const struct net_device_ops tun_netdev_ops = { 816 .ndo_uninit = tun_net_uninit, 817 .ndo_open = tun_net_open, 818 .ndo_stop = tun_net_close, 819 .ndo_start_xmit = tun_net_xmit, 820 .ndo_change_mtu = tun_net_change_mtu, 821 .ndo_fix_features = tun_net_fix_features, 822 .ndo_select_queue = tun_select_queue, 823 #ifdef CONFIG_NET_POLL_CONTROLLER 824 .ndo_poll_controller = tun_poll_controller, 825 #endif 826 }; 827 828 static const struct net_device_ops tap_netdev_ops = { 829 .ndo_uninit = tun_net_uninit, 830 .ndo_open = tun_net_open, 831 .ndo_stop = tun_net_close, 832 .ndo_start_xmit = tun_net_xmit, 833 .ndo_change_mtu = tun_net_change_mtu, 834 .ndo_fix_features = tun_net_fix_features, 835 .ndo_set_rx_mode = tun_net_mclist, 836 .ndo_set_mac_address = eth_mac_addr, 837 .ndo_validate_addr = eth_validate_addr, 838 .ndo_select_queue = tun_select_queue, 839 #ifdef CONFIG_NET_POLL_CONTROLLER 840 .ndo_poll_controller = tun_poll_controller, 841 #endif 842 }; 843 844 static void tun_flow_init(struct tun_struct *tun) 845 { 846 int i; 847 848 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 849 INIT_HLIST_HEAD(&tun->flows[i]); 850 851 tun->ageing_time = TUN_FLOW_EXPIRE; 852 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 853 mod_timer(&tun->flow_gc_timer, 854 round_jiffies_up(jiffies + tun->ageing_time)); 855 } 856 857 static void tun_flow_uninit(struct tun_struct *tun) 858 { 859 del_timer_sync(&tun->flow_gc_timer); 860 tun_flow_flush(tun); 861 } 862 863 /* Initialize net device. */ 864 static void tun_net_init(struct net_device *dev) 865 { 866 struct tun_struct *tun = netdev_priv(dev); 867 868 switch (tun->flags & TUN_TYPE_MASK) { 869 case TUN_TUN_DEV: 870 dev->netdev_ops = &tun_netdev_ops; 871 872 /* Point-to-Point TUN Device */ 873 dev->hard_header_len = 0; 874 dev->addr_len = 0; 875 dev->mtu = 1500; 876 877 /* Zero header length */ 878 dev->type = ARPHRD_NONE; 879 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 880 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 881 break; 882 883 case TUN_TAP_DEV: 884 dev->netdev_ops = &tap_netdev_ops; 885 /* Ethernet TAP Device */ 886 ether_setup(dev); 887 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 888 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 889 890 eth_hw_addr_random(dev); 891 892 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 893 break; 894 } 895 } 896 897 /* Character device part */ 898 899 /* Poll */ 900 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 901 { 902 struct tun_file *tfile = file->private_data; 903 struct tun_struct *tun = __tun_get(tfile); 904 struct sock *sk; 905 unsigned int mask = 0; 906 907 if (!tun) 908 return POLLERR; 909 910 sk = tfile->socket.sk; 911 912 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 913 914 poll_wait(file, &tfile->wq.wait, wait); 915 916 if (!skb_queue_empty(&sk->sk_receive_queue)) 917 mask |= POLLIN | POLLRDNORM; 918 919 if (sock_writeable(sk) || 920 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 921 sock_writeable(sk))) 922 mask |= POLLOUT | POLLWRNORM; 923 924 if (tun->dev->reg_state != NETREG_REGISTERED) 925 mask = POLLERR; 926 927 tun_put(tun); 928 return mask; 929 } 930 931 /* prepad is the amount to reserve at front. len is length after that. 932 * linear is a hint as to how much to copy (usually headers). */ 933 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 934 size_t prepad, size_t len, 935 size_t linear, int noblock) 936 { 937 struct sock *sk = tfile->socket.sk; 938 struct sk_buff *skb; 939 int err; 940 941 /* Under a page? Don't bother with paged skb. */ 942 if (prepad + len < PAGE_SIZE || !linear) 943 linear = len; 944 945 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 946 &err); 947 if (!skb) 948 return ERR_PTR(err); 949 950 skb_reserve(skb, prepad); 951 skb_put(skb, linear); 952 skb->data_len = len - linear; 953 skb->len += len - linear; 954 955 return skb; 956 } 957 958 /* set skb frags from iovec, this can move to core network code for reuse */ 959 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, 960 int offset, size_t count) 961 { 962 int len = iov_length(from, count) - offset; 963 int copy = skb_headlen(skb); 964 int size, offset1 = 0; 965 int i = 0; 966 967 /* Skip over from offset */ 968 while (count && (offset >= from->iov_len)) { 969 offset -= from->iov_len; 970 ++from; 971 --count; 972 } 973 974 /* copy up to skb headlen */ 975 while (count && (copy > 0)) { 976 size = min_t(unsigned int, copy, from->iov_len - offset); 977 if (copy_from_user(skb->data + offset1, from->iov_base + offset, 978 size)) 979 return -EFAULT; 980 if (copy > size) { 981 ++from; 982 --count; 983 offset = 0; 984 } else 985 offset += size; 986 copy -= size; 987 offset1 += size; 988 } 989 990 if (len == offset1) 991 return 0; 992 993 while (count--) { 994 struct page *page[MAX_SKB_FRAGS]; 995 int num_pages; 996 unsigned long base; 997 unsigned long truesize; 998 999 len = from->iov_len - offset; 1000 if (!len) { 1001 offset = 0; 1002 ++from; 1003 continue; 1004 } 1005 base = (unsigned long)from->iov_base + offset; 1006 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; 1007 if (i + size > MAX_SKB_FRAGS) 1008 return -EMSGSIZE; 1009 num_pages = get_user_pages_fast(base, size, 0, &page[i]); 1010 if (num_pages != size) { 1011 int j; 1012 1013 for (j = 0; j < num_pages; j++) 1014 put_page(page[i + j]); 1015 return -EFAULT; 1016 } 1017 truesize = size * PAGE_SIZE; 1018 skb->data_len += len; 1019 skb->len += len; 1020 skb->truesize += truesize; 1021 atomic_add(truesize, &skb->sk->sk_wmem_alloc); 1022 while (len) { 1023 int off = base & ~PAGE_MASK; 1024 int size = min_t(int, len, PAGE_SIZE - off); 1025 __skb_fill_page_desc(skb, i, page[i], off, size); 1026 skb_shinfo(skb)->nr_frags++; 1027 /* increase sk_wmem_alloc */ 1028 base += size; 1029 len -= size; 1030 i++; 1031 } 1032 offset = 0; 1033 ++from; 1034 } 1035 return 0; 1036 } 1037 1038 static unsigned long iov_pages(const struct iovec *iv, int offset, 1039 unsigned long nr_segs) 1040 { 1041 unsigned long seg, base; 1042 int pages = 0, len, size; 1043 1044 while (nr_segs && (offset >= iv->iov_len)) { 1045 offset -= iv->iov_len; 1046 ++iv; 1047 --nr_segs; 1048 } 1049 1050 for (seg = 0; seg < nr_segs; seg++) { 1051 base = (unsigned long)iv[seg].iov_base + offset; 1052 len = iv[seg].iov_len - offset; 1053 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; 1054 pages += size; 1055 offset = 0; 1056 } 1057 1058 return pages; 1059 } 1060 1061 /* Get packet from user space buffer */ 1062 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1063 void *msg_control, const struct iovec *iv, 1064 size_t total_len, size_t count, int noblock) 1065 { 1066 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1067 struct sk_buff *skb; 1068 size_t len = total_len, align = NET_SKB_PAD, linear; 1069 struct virtio_net_hdr gso = { 0 }; 1070 int offset = 0; 1071 int copylen; 1072 bool zerocopy = false; 1073 int err; 1074 u32 rxhash; 1075 1076 if (!(tun->flags & TUN_NO_PI)) { 1077 if ((len -= sizeof(pi)) > total_len) 1078 return -EINVAL; 1079 1080 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) 1081 return -EFAULT; 1082 offset += sizeof(pi); 1083 } 1084 1085 if (tun->flags & TUN_VNET_HDR) { 1086 if ((len -= tun->vnet_hdr_sz) > total_len) 1087 return -EINVAL; 1088 1089 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) 1090 return -EFAULT; 1091 1092 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1093 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) 1094 gso.hdr_len = gso.csum_start + gso.csum_offset + 2; 1095 1096 if (gso.hdr_len > len) 1097 return -EINVAL; 1098 offset += tun->vnet_hdr_sz; 1099 } 1100 1101 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { 1102 align += NET_IP_ALIGN; 1103 if (unlikely(len < ETH_HLEN || 1104 (gso.hdr_len && gso.hdr_len < ETH_HLEN))) 1105 return -EINVAL; 1106 } 1107 1108 if (msg_control) { 1109 /* There are 256 bytes to be copied in skb, so there is 1110 * enough room for skb expand head in case it is used. 1111 * The rest of the buffer is mapped from userspace. 1112 */ 1113 copylen = gso.hdr_len ? gso.hdr_len : GOODCOPY_LEN; 1114 linear = copylen; 1115 if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS) 1116 zerocopy = true; 1117 } 1118 1119 if (!zerocopy) { 1120 copylen = len; 1121 linear = gso.hdr_len; 1122 } 1123 1124 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1125 if (IS_ERR(skb)) { 1126 if (PTR_ERR(skb) != -EAGAIN) 1127 tun->dev->stats.rx_dropped++; 1128 return PTR_ERR(skb); 1129 } 1130 1131 if (zerocopy) 1132 err = zerocopy_sg_from_iovec(skb, iv, offset, count); 1133 else { 1134 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len); 1135 if (!err && msg_control) { 1136 struct ubuf_info *uarg = msg_control; 1137 uarg->callback(uarg, false); 1138 } 1139 } 1140 1141 if (err) { 1142 tun->dev->stats.rx_dropped++; 1143 kfree_skb(skb); 1144 return -EFAULT; 1145 } 1146 1147 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1148 if (!skb_partial_csum_set(skb, gso.csum_start, 1149 gso.csum_offset)) { 1150 tun->dev->stats.rx_frame_errors++; 1151 kfree_skb(skb); 1152 return -EINVAL; 1153 } 1154 } 1155 1156 switch (tun->flags & TUN_TYPE_MASK) { 1157 case TUN_TUN_DEV: 1158 if (tun->flags & TUN_NO_PI) { 1159 switch (skb->data[0] & 0xf0) { 1160 case 0x40: 1161 pi.proto = htons(ETH_P_IP); 1162 break; 1163 case 0x60: 1164 pi.proto = htons(ETH_P_IPV6); 1165 break; 1166 default: 1167 tun->dev->stats.rx_dropped++; 1168 kfree_skb(skb); 1169 return -EINVAL; 1170 } 1171 } 1172 1173 skb_reset_mac_header(skb); 1174 skb->protocol = pi.proto; 1175 skb->dev = tun->dev; 1176 break; 1177 case TUN_TAP_DEV: 1178 skb->protocol = eth_type_trans(skb, tun->dev); 1179 break; 1180 } 1181 1182 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1183 pr_debug("GSO!\n"); 1184 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1185 case VIRTIO_NET_HDR_GSO_TCPV4: 1186 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1187 break; 1188 case VIRTIO_NET_HDR_GSO_TCPV6: 1189 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1190 break; 1191 case VIRTIO_NET_HDR_GSO_UDP: 1192 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1193 break; 1194 default: 1195 tun->dev->stats.rx_frame_errors++; 1196 kfree_skb(skb); 1197 return -EINVAL; 1198 } 1199 1200 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1201 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1202 1203 skb_shinfo(skb)->gso_size = gso.gso_size; 1204 if (skb_shinfo(skb)->gso_size == 0) { 1205 tun->dev->stats.rx_frame_errors++; 1206 kfree_skb(skb); 1207 return -EINVAL; 1208 } 1209 1210 /* Header must be checked, and gso_segs computed. */ 1211 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1212 skb_shinfo(skb)->gso_segs = 0; 1213 } 1214 1215 /* copy skb_ubuf_info for callback when skb has no error */ 1216 if (zerocopy) { 1217 skb_shinfo(skb)->destructor_arg = msg_control; 1218 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1219 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1220 } 1221 1222 skb_reset_network_header(skb); 1223 skb_probe_transport_header(skb, 0); 1224 1225 rxhash = skb_get_rxhash(skb); 1226 netif_rx_ni(skb); 1227 1228 tun->dev->stats.rx_packets++; 1229 tun->dev->stats.rx_bytes += len; 1230 1231 tun_flow_update(tun, rxhash, tfile); 1232 return total_len; 1233 } 1234 1235 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 1236 unsigned long count, loff_t pos) 1237 { 1238 struct file *file = iocb->ki_filp; 1239 struct tun_struct *tun = tun_get(file); 1240 struct tun_file *tfile = file->private_data; 1241 ssize_t result; 1242 1243 if (!tun) 1244 return -EBADFD; 1245 1246 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count); 1247 1248 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count), 1249 count, file->f_flags & O_NONBLOCK); 1250 1251 tun_put(tun); 1252 return result; 1253 } 1254 1255 /* Put packet to the user space buffer */ 1256 static ssize_t tun_put_user(struct tun_struct *tun, 1257 struct tun_file *tfile, 1258 struct sk_buff *skb, 1259 const struct iovec *iv, int len) 1260 { 1261 struct tun_pi pi = { 0, skb->protocol }; 1262 ssize_t total = 0; 1263 1264 if (!(tun->flags & TUN_NO_PI)) { 1265 if ((len -= sizeof(pi)) < 0) 1266 return -EINVAL; 1267 1268 if (len < skb->len) { 1269 /* Packet will be striped */ 1270 pi.flags |= TUN_PKT_STRIP; 1271 } 1272 1273 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi))) 1274 return -EFAULT; 1275 total += sizeof(pi); 1276 } 1277 1278 if (tun->flags & TUN_VNET_HDR) { 1279 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1280 if ((len -= tun->vnet_hdr_sz) < 0) 1281 return -EINVAL; 1282 1283 if (skb_is_gso(skb)) { 1284 struct skb_shared_info *sinfo = skb_shinfo(skb); 1285 1286 /* This is a hint as to how much should be linear. */ 1287 gso.hdr_len = skb_headlen(skb); 1288 gso.gso_size = sinfo->gso_size; 1289 if (sinfo->gso_type & SKB_GSO_TCPV4) 1290 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1291 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1292 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1293 else if (sinfo->gso_type & SKB_GSO_UDP) 1294 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1295 else { 1296 pr_err("unexpected GSO type: " 1297 "0x%x, gso_size %d, hdr_len %d\n", 1298 sinfo->gso_type, gso.gso_size, 1299 gso.hdr_len); 1300 print_hex_dump(KERN_ERR, "tun: ", 1301 DUMP_PREFIX_NONE, 1302 16, 1, skb->head, 1303 min((int)gso.hdr_len, 64), true); 1304 WARN_ON_ONCE(1); 1305 return -EINVAL; 1306 } 1307 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1308 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1309 } else 1310 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1311 1312 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1313 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1314 gso.csum_start = skb_checksum_start_offset(skb); 1315 gso.csum_offset = skb->csum_offset; 1316 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1317 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1318 } /* else everything is zero */ 1319 1320 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, 1321 sizeof(gso)))) 1322 return -EFAULT; 1323 total += tun->vnet_hdr_sz; 1324 } 1325 1326 len = min_t(int, skb->len, len); 1327 1328 skb_copy_datagram_const_iovec(skb, 0, iv, total, len); 1329 total += skb->len; 1330 1331 tun->dev->stats.tx_packets++; 1332 tun->dev->stats.tx_bytes += len; 1333 1334 return total; 1335 } 1336 1337 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1338 struct kiocb *iocb, const struct iovec *iv, 1339 ssize_t len, int noblock) 1340 { 1341 DECLARE_WAITQUEUE(wait, current); 1342 struct sk_buff *skb; 1343 ssize_t ret = 0; 1344 1345 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1346 1347 if (unlikely(!noblock)) 1348 add_wait_queue(&tfile->wq.wait, &wait); 1349 while (len) { 1350 current->state = TASK_INTERRUPTIBLE; 1351 1352 /* Read frames from the queue */ 1353 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) { 1354 if (noblock) { 1355 ret = -EAGAIN; 1356 break; 1357 } 1358 if (signal_pending(current)) { 1359 ret = -ERESTARTSYS; 1360 break; 1361 } 1362 if (tun->dev->reg_state != NETREG_REGISTERED) { 1363 ret = -EIO; 1364 break; 1365 } 1366 1367 /* Nothing to read, let's sleep */ 1368 schedule(); 1369 continue; 1370 } 1371 1372 ret = tun_put_user(tun, tfile, skb, iv, len); 1373 kfree_skb(skb); 1374 break; 1375 } 1376 1377 current->state = TASK_RUNNING; 1378 if (unlikely(!noblock)) 1379 remove_wait_queue(&tfile->wq.wait, &wait); 1380 1381 return ret; 1382 } 1383 1384 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 1385 unsigned long count, loff_t pos) 1386 { 1387 struct file *file = iocb->ki_filp; 1388 struct tun_file *tfile = file->private_data; 1389 struct tun_struct *tun = __tun_get(tfile); 1390 ssize_t len, ret; 1391 1392 if (!tun) 1393 return -EBADFD; 1394 len = iov_length(iv, count); 1395 if (len < 0) { 1396 ret = -EINVAL; 1397 goto out; 1398 } 1399 1400 ret = tun_do_read(tun, tfile, iocb, iv, len, 1401 file->f_flags & O_NONBLOCK); 1402 ret = min_t(ssize_t, ret, len); 1403 out: 1404 tun_put(tun); 1405 return ret; 1406 } 1407 1408 static void tun_free_netdev(struct net_device *dev) 1409 { 1410 struct tun_struct *tun = netdev_priv(dev); 1411 1412 BUG_ON(!(list_empty(&tun->disabled))); 1413 tun_flow_uninit(tun); 1414 security_tun_dev_free_security(tun->security); 1415 free_netdev(dev); 1416 } 1417 1418 static void tun_setup(struct net_device *dev) 1419 { 1420 struct tun_struct *tun = netdev_priv(dev); 1421 1422 tun->owner = INVALID_UID; 1423 tun->group = INVALID_GID; 1424 1425 dev->ethtool_ops = &tun_ethtool_ops; 1426 dev->destructor = tun_free_netdev; 1427 } 1428 1429 /* Trivial set of netlink ops to allow deleting tun or tap 1430 * device with netlink. 1431 */ 1432 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1433 { 1434 return -EINVAL; 1435 } 1436 1437 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1438 .kind = DRV_NAME, 1439 .priv_size = sizeof(struct tun_struct), 1440 .setup = tun_setup, 1441 .validate = tun_validate, 1442 }; 1443 1444 static void tun_sock_write_space(struct sock *sk) 1445 { 1446 struct tun_file *tfile; 1447 wait_queue_head_t *wqueue; 1448 1449 if (!sock_writeable(sk)) 1450 return; 1451 1452 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1453 return; 1454 1455 wqueue = sk_sleep(sk); 1456 if (wqueue && waitqueue_active(wqueue)) 1457 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1458 POLLWRNORM | POLLWRBAND); 1459 1460 tfile = container_of(sk, struct tun_file, sk); 1461 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1462 } 1463 1464 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1465 struct msghdr *m, size_t total_len) 1466 { 1467 int ret; 1468 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1469 struct tun_struct *tun = __tun_get(tfile); 1470 1471 if (!tun) 1472 return -EBADFD; 1473 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len, 1474 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); 1475 tun_put(tun); 1476 return ret; 1477 } 1478 1479 1480 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1481 struct msghdr *m, size_t total_len, 1482 int flags) 1483 { 1484 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1485 struct tun_struct *tun = __tun_get(tfile); 1486 int ret; 1487 1488 if (!tun) 1489 return -EBADFD; 1490 1491 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) { 1492 ret = -EINVAL; 1493 goto out; 1494 } 1495 ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len, 1496 flags & MSG_DONTWAIT); 1497 if (ret > total_len) { 1498 m->msg_flags |= MSG_TRUNC; 1499 ret = flags & MSG_TRUNC ? ret : total_len; 1500 } 1501 out: 1502 tun_put(tun); 1503 return ret; 1504 } 1505 1506 static int tun_release(struct socket *sock) 1507 { 1508 if (sock->sk) 1509 sock_put(sock->sk); 1510 return 0; 1511 } 1512 1513 /* Ops structure to mimic raw sockets with tun */ 1514 static const struct proto_ops tun_socket_ops = { 1515 .sendmsg = tun_sendmsg, 1516 .recvmsg = tun_recvmsg, 1517 .release = tun_release, 1518 }; 1519 1520 static struct proto tun_proto = { 1521 .name = "tun", 1522 .owner = THIS_MODULE, 1523 .obj_size = sizeof(struct tun_file), 1524 }; 1525 1526 static int tun_flags(struct tun_struct *tun) 1527 { 1528 int flags = 0; 1529 1530 if (tun->flags & TUN_TUN_DEV) 1531 flags |= IFF_TUN; 1532 else 1533 flags |= IFF_TAP; 1534 1535 if (tun->flags & TUN_NO_PI) 1536 flags |= IFF_NO_PI; 1537 1538 /* This flag has no real effect. We track the value for backwards 1539 * compatibility. 1540 */ 1541 if (tun->flags & TUN_ONE_QUEUE) 1542 flags |= IFF_ONE_QUEUE; 1543 1544 if (tun->flags & TUN_VNET_HDR) 1545 flags |= IFF_VNET_HDR; 1546 1547 if (tun->flags & TUN_TAP_MQ) 1548 flags |= IFF_MULTI_QUEUE; 1549 1550 if (tun->flags & TUN_PERSIST) 1551 flags |= IFF_PERSIST; 1552 1553 return flags; 1554 } 1555 1556 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1557 char *buf) 1558 { 1559 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1560 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1561 } 1562 1563 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1564 char *buf) 1565 { 1566 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1567 return uid_valid(tun->owner)? 1568 sprintf(buf, "%u\n", 1569 from_kuid_munged(current_user_ns(), tun->owner)): 1570 sprintf(buf, "-1\n"); 1571 } 1572 1573 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1574 char *buf) 1575 { 1576 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1577 return gid_valid(tun->group) ? 1578 sprintf(buf, "%u\n", 1579 from_kgid_munged(current_user_ns(), tun->group)): 1580 sprintf(buf, "-1\n"); 1581 } 1582 1583 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1584 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1585 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1586 1587 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1588 { 1589 struct tun_struct *tun; 1590 struct tun_file *tfile = file->private_data; 1591 struct net_device *dev; 1592 int err; 1593 1594 if (tfile->detached) 1595 return -EINVAL; 1596 1597 dev = __dev_get_by_name(net, ifr->ifr_name); 1598 if (dev) { 1599 if (ifr->ifr_flags & IFF_TUN_EXCL) 1600 return -EBUSY; 1601 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1602 tun = netdev_priv(dev); 1603 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1604 tun = netdev_priv(dev); 1605 else 1606 return -EINVAL; 1607 1608 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1609 !!(tun->flags & TUN_TAP_MQ)) 1610 return -EINVAL; 1611 1612 if (tun_not_capable(tun)) 1613 return -EPERM; 1614 err = security_tun_dev_open(tun->security); 1615 if (err < 0) 1616 return err; 1617 1618 err = tun_attach(tun, file); 1619 if (err < 0) 1620 return err; 1621 1622 if (tun->flags & TUN_TAP_MQ && 1623 (tun->numqueues + tun->numdisabled > 1)) { 1624 /* One or more queue has already been attached, no need 1625 * to initialize the device again. 1626 */ 1627 return 0; 1628 } 1629 } 1630 else { 1631 char *name; 1632 unsigned long flags = 0; 1633 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1634 MAX_TAP_QUEUES : 1; 1635 1636 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1637 return -EPERM; 1638 err = security_tun_dev_create(); 1639 if (err < 0) 1640 return err; 1641 1642 /* Set dev type */ 1643 if (ifr->ifr_flags & IFF_TUN) { 1644 /* TUN device */ 1645 flags |= TUN_TUN_DEV; 1646 name = "tun%d"; 1647 } else if (ifr->ifr_flags & IFF_TAP) { 1648 /* TAP device */ 1649 flags |= TUN_TAP_DEV; 1650 name = "tap%d"; 1651 } else 1652 return -EINVAL; 1653 1654 if (*ifr->ifr_name) 1655 name = ifr->ifr_name; 1656 1657 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1658 tun_setup, queues, queues); 1659 1660 if (!dev) 1661 return -ENOMEM; 1662 1663 dev_net_set(dev, net); 1664 dev->rtnl_link_ops = &tun_link_ops; 1665 1666 tun = netdev_priv(dev); 1667 tun->dev = dev; 1668 tun->flags = flags; 1669 tun->txflt.count = 0; 1670 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1671 1672 tun->filter_attached = false; 1673 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1674 1675 spin_lock_init(&tun->lock); 1676 1677 err = security_tun_dev_alloc_security(&tun->security); 1678 if (err < 0) 1679 goto err_free_dev; 1680 1681 tun_net_init(dev); 1682 tun_flow_init(tun); 1683 1684 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1685 TUN_USER_FEATURES; 1686 dev->features = dev->hw_features; 1687 dev->vlan_features = dev->features; 1688 1689 INIT_LIST_HEAD(&tun->disabled); 1690 err = tun_attach(tun, file); 1691 if (err < 0) 1692 goto err_free_dev; 1693 1694 err = register_netdevice(tun->dev); 1695 if (err < 0) 1696 goto err_free_dev; 1697 1698 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1699 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1700 device_create_file(&tun->dev->dev, &dev_attr_group)) 1701 pr_err("Failed to create tun sysfs files\n"); 1702 } 1703 1704 netif_carrier_on(tun->dev); 1705 1706 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1707 1708 if (ifr->ifr_flags & IFF_NO_PI) 1709 tun->flags |= TUN_NO_PI; 1710 else 1711 tun->flags &= ~TUN_NO_PI; 1712 1713 /* This flag has no real effect. We track the value for backwards 1714 * compatibility. 1715 */ 1716 if (ifr->ifr_flags & IFF_ONE_QUEUE) 1717 tun->flags |= TUN_ONE_QUEUE; 1718 else 1719 tun->flags &= ~TUN_ONE_QUEUE; 1720 1721 if (ifr->ifr_flags & IFF_VNET_HDR) 1722 tun->flags |= TUN_VNET_HDR; 1723 else 1724 tun->flags &= ~TUN_VNET_HDR; 1725 1726 if (ifr->ifr_flags & IFF_MULTI_QUEUE) 1727 tun->flags |= TUN_TAP_MQ; 1728 else 1729 tun->flags &= ~TUN_TAP_MQ; 1730 1731 /* Make sure persistent devices do not get stuck in 1732 * xoff state. 1733 */ 1734 if (netif_running(tun->dev)) 1735 netif_tx_wake_all_queues(tun->dev); 1736 1737 strcpy(ifr->ifr_name, tun->dev->name); 1738 return 0; 1739 1740 err_free_dev: 1741 free_netdev(dev); 1742 return err; 1743 } 1744 1745 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1746 struct ifreq *ifr) 1747 { 1748 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1749 1750 strcpy(ifr->ifr_name, tun->dev->name); 1751 1752 ifr->ifr_flags = tun_flags(tun); 1753 1754 } 1755 1756 /* This is like a cut-down ethtool ops, except done via tun fd so no 1757 * privs required. */ 1758 static int set_offload(struct tun_struct *tun, unsigned long arg) 1759 { 1760 netdev_features_t features = 0; 1761 1762 if (arg & TUN_F_CSUM) { 1763 features |= NETIF_F_HW_CSUM; 1764 arg &= ~TUN_F_CSUM; 1765 1766 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1767 if (arg & TUN_F_TSO_ECN) { 1768 features |= NETIF_F_TSO_ECN; 1769 arg &= ~TUN_F_TSO_ECN; 1770 } 1771 if (arg & TUN_F_TSO4) 1772 features |= NETIF_F_TSO; 1773 if (arg & TUN_F_TSO6) 1774 features |= NETIF_F_TSO6; 1775 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1776 } 1777 1778 if (arg & TUN_F_UFO) { 1779 features |= NETIF_F_UFO; 1780 arg &= ~TUN_F_UFO; 1781 } 1782 } 1783 1784 /* This gives the user a way to test for new features in future by 1785 * trying to set them. */ 1786 if (arg) 1787 return -EINVAL; 1788 1789 tun->set_features = features; 1790 netdev_update_features(tun->dev); 1791 1792 return 0; 1793 } 1794 1795 static void tun_detach_filter(struct tun_struct *tun, int n) 1796 { 1797 int i; 1798 struct tun_file *tfile; 1799 1800 for (i = 0; i < n; i++) { 1801 tfile = rtnl_dereference(tun->tfiles[i]); 1802 sk_detach_filter(tfile->socket.sk); 1803 } 1804 1805 tun->filter_attached = false; 1806 } 1807 1808 static int tun_attach_filter(struct tun_struct *tun) 1809 { 1810 int i, ret = 0; 1811 struct tun_file *tfile; 1812 1813 for (i = 0; i < tun->numqueues; i++) { 1814 tfile = rtnl_dereference(tun->tfiles[i]); 1815 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1816 if (ret) { 1817 tun_detach_filter(tun, i); 1818 return ret; 1819 } 1820 } 1821 1822 tun->filter_attached = true; 1823 return ret; 1824 } 1825 1826 static void tun_set_sndbuf(struct tun_struct *tun) 1827 { 1828 struct tun_file *tfile; 1829 int i; 1830 1831 for (i = 0; i < tun->numqueues; i++) { 1832 tfile = rtnl_dereference(tun->tfiles[i]); 1833 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1834 } 1835 } 1836 1837 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1838 { 1839 struct tun_file *tfile = file->private_data; 1840 struct tun_struct *tun; 1841 int ret = 0; 1842 1843 rtnl_lock(); 1844 1845 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1846 tun = tfile->detached; 1847 if (!tun) { 1848 ret = -EINVAL; 1849 goto unlock; 1850 } 1851 ret = security_tun_dev_attach_queue(tun->security); 1852 if (ret < 0) 1853 goto unlock; 1854 ret = tun_attach(tun, file); 1855 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1856 tun = rtnl_dereference(tfile->tun); 1857 if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) 1858 ret = -EINVAL; 1859 else 1860 __tun_detach(tfile, false); 1861 } else 1862 ret = -EINVAL; 1863 1864 unlock: 1865 rtnl_unlock(); 1866 return ret; 1867 } 1868 1869 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1870 unsigned long arg, int ifreq_len) 1871 { 1872 struct tun_file *tfile = file->private_data; 1873 struct tun_struct *tun; 1874 void __user* argp = (void __user*)arg; 1875 struct ifreq ifr; 1876 kuid_t owner; 1877 kgid_t group; 1878 int sndbuf; 1879 int vnet_hdr_sz; 1880 int ret; 1881 1882 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1883 if (copy_from_user(&ifr, argp, ifreq_len)) 1884 return -EFAULT; 1885 } else { 1886 memset(&ifr, 0, sizeof(ifr)); 1887 } 1888 if (cmd == TUNGETFEATURES) { 1889 /* Currently this just means: "what IFF flags are valid?". 1890 * This is needed because we never checked for invalid flags on 1891 * TUNSETIFF. */ 1892 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | 1893 IFF_VNET_HDR | IFF_MULTI_QUEUE, 1894 (unsigned int __user*)argp); 1895 } else if (cmd == TUNSETQUEUE) 1896 return tun_set_queue(file, &ifr); 1897 1898 ret = 0; 1899 rtnl_lock(); 1900 1901 tun = __tun_get(tfile); 1902 if (cmd == TUNSETIFF && !tun) { 1903 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1904 1905 ret = tun_set_iff(tfile->net, file, &ifr); 1906 1907 if (ret) 1908 goto unlock; 1909 1910 if (copy_to_user(argp, &ifr, ifreq_len)) 1911 ret = -EFAULT; 1912 goto unlock; 1913 } 1914 1915 ret = -EBADFD; 1916 if (!tun) 1917 goto unlock; 1918 1919 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1920 1921 ret = 0; 1922 switch (cmd) { 1923 case TUNGETIFF: 1924 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1925 1926 if (copy_to_user(argp, &ifr, ifreq_len)) 1927 ret = -EFAULT; 1928 break; 1929 1930 case TUNSETNOCSUM: 1931 /* Disable/Enable checksum */ 1932 1933 /* [unimplemented] */ 1934 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1935 arg ? "disabled" : "enabled"); 1936 break; 1937 1938 case TUNSETPERSIST: 1939 /* Disable/Enable persist mode. Keep an extra reference to the 1940 * module to prevent the module being unprobed. 1941 */ 1942 if (arg && !(tun->flags & TUN_PERSIST)) { 1943 tun->flags |= TUN_PERSIST; 1944 __module_get(THIS_MODULE); 1945 } 1946 if (!arg && (tun->flags & TUN_PERSIST)) { 1947 tun->flags &= ~TUN_PERSIST; 1948 module_put(THIS_MODULE); 1949 } 1950 1951 tun_debug(KERN_INFO, tun, "persist %s\n", 1952 arg ? "enabled" : "disabled"); 1953 break; 1954 1955 case TUNSETOWNER: 1956 /* Set owner of the device */ 1957 owner = make_kuid(current_user_ns(), arg); 1958 if (!uid_valid(owner)) { 1959 ret = -EINVAL; 1960 break; 1961 } 1962 tun->owner = owner; 1963 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1964 from_kuid(&init_user_ns, tun->owner)); 1965 break; 1966 1967 case TUNSETGROUP: 1968 /* Set group of the device */ 1969 group = make_kgid(current_user_ns(), arg); 1970 if (!gid_valid(group)) { 1971 ret = -EINVAL; 1972 break; 1973 } 1974 tun->group = group; 1975 tun_debug(KERN_INFO, tun, "group set to %u\n", 1976 from_kgid(&init_user_ns, tun->group)); 1977 break; 1978 1979 case TUNSETLINK: 1980 /* Only allow setting the type when the interface is down */ 1981 if (tun->dev->flags & IFF_UP) { 1982 tun_debug(KERN_INFO, tun, 1983 "Linktype set failed because interface is up\n"); 1984 ret = -EBUSY; 1985 } else { 1986 tun->dev->type = (int) arg; 1987 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1988 tun->dev->type); 1989 ret = 0; 1990 } 1991 break; 1992 1993 #ifdef TUN_DEBUG 1994 case TUNSETDEBUG: 1995 tun->debug = arg; 1996 break; 1997 #endif 1998 case TUNSETOFFLOAD: 1999 ret = set_offload(tun, arg); 2000 break; 2001 2002 case TUNSETTXFILTER: 2003 /* Can be set only for TAPs */ 2004 ret = -EINVAL; 2005 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2006 break; 2007 ret = update_filter(&tun->txflt, (void __user *)arg); 2008 break; 2009 2010 case SIOCGIFHWADDR: 2011 /* Get hw address */ 2012 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 2013 ifr.ifr_hwaddr.sa_family = tun->dev->type; 2014 if (copy_to_user(argp, &ifr, ifreq_len)) 2015 ret = -EFAULT; 2016 break; 2017 2018 case SIOCSIFHWADDR: 2019 /* Set hw address */ 2020 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 2021 ifr.ifr_hwaddr.sa_data); 2022 2023 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2024 break; 2025 2026 case TUNGETSNDBUF: 2027 sndbuf = tfile->socket.sk->sk_sndbuf; 2028 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2029 ret = -EFAULT; 2030 break; 2031 2032 case TUNSETSNDBUF: 2033 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2034 ret = -EFAULT; 2035 break; 2036 } 2037 2038 tun->sndbuf = sndbuf; 2039 tun_set_sndbuf(tun); 2040 break; 2041 2042 case TUNGETVNETHDRSZ: 2043 vnet_hdr_sz = tun->vnet_hdr_sz; 2044 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2045 ret = -EFAULT; 2046 break; 2047 2048 case TUNSETVNETHDRSZ: 2049 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2050 ret = -EFAULT; 2051 break; 2052 } 2053 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2054 ret = -EINVAL; 2055 break; 2056 } 2057 2058 tun->vnet_hdr_sz = vnet_hdr_sz; 2059 break; 2060 2061 case TUNATTACHFILTER: 2062 /* Can be set only for TAPs */ 2063 ret = -EINVAL; 2064 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2065 break; 2066 ret = -EFAULT; 2067 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2068 break; 2069 2070 ret = tun_attach_filter(tun); 2071 break; 2072 2073 case TUNDETACHFILTER: 2074 /* Can be set only for TAPs */ 2075 ret = -EINVAL; 2076 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2077 break; 2078 ret = 0; 2079 tun_detach_filter(tun, tun->numqueues); 2080 break; 2081 2082 default: 2083 ret = -EINVAL; 2084 break; 2085 } 2086 2087 unlock: 2088 rtnl_unlock(); 2089 if (tun) 2090 tun_put(tun); 2091 return ret; 2092 } 2093 2094 static long tun_chr_ioctl(struct file *file, 2095 unsigned int cmd, unsigned long arg) 2096 { 2097 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2098 } 2099 2100 #ifdef CONFIG_COMPAT 2101 static long tun_chr_compat_ioctl(struct file *file, 2102 unsigned int cmd, unsigned long arg) 2103 { 2104 switch (cmd) { 2105 case TUNSETIFF: 2106 case TUNGETIFF: 2107 case TUNSETTXFILTER: 2108 case TUNGETSNDBUF: 2109 case TUNSETSNDBUF: 2110 case SIOCGIFHWADDR: 2111 case SIOCSIFHWADDR: 2112 arg = (unsigned long)compat_ptr(arg); 2113 break; 2114 default: 2115 arg = (compat_ulong_t)arg; 2116 break; 2117 } 2118 2119 /* 2120 * compat_ifreq is shorter than ifreq, so we must not access beyond 2121 * the end of that structure. All fields that are used in this 2122 * driver are compatible though, we don't need to convert the 2123 * contents. 2124 */ 2125 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2126 } 2127 #endif /* CONFIG_COMPAT */ 2128 2129 static int tun_chr_fasync(int fd, struct file *file, int on) 2130 { 2131 struct tun_file *tfile = file->private_data; 2132 int ret; 2133 2134 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2135 goto out; 2136 2137 if (on) { 2138 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2139 if (ret) 2140 goto out; 2141 tfile->flags |= TUN_FASYNC; 2142 } else 2143 tfile->flags &= ~TUN_FASYNC; 2144 ret = 0; 2145 out: 2146 return ret; 2147 } 2148 2149 static int tun_chr_open(struct inode *inode, struct file * file) 2150 { 2151 struct tun_file *tfile; 2152 2153 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2154 2155 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2156 &tun_proto); 2157 if (!tfile) 2158 return -ENOMEM; 2159 rcu_assign_pointer(tfile->tun, NULL); 2160 tfile->net = get_net(current->nsproxy->net_ns); 2161 tfile->flags = 0; 2162 2163 rcu_assign_pointer(tfile->socket.wq, &tfile->wq); 2164 init_waitqueue_head(&tfile->wq.wait); 2165 2166 tfile->socket.file = file; 2167 tfile->socket.ops = &tun_socket_ops; 2168 2169 sock_init_data(&tfile->socket, &tfile->sk); 2170 sk_change_net(&tfile->sk, tfile->net); 2171 2172 tfile->sk.sk_write_space = tun_sock_write_space; 2173 tfile->sk.sk_sndbuf = INT_MAX; 2174 2175 file->private_data = tfile; 2176 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2177 INIT_LIST_HEAD(&tfile->next); 2178 2179 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2180 2181 return 0; 2182 } 2183 2184 static int tun_chr_close(struct inode *inode, struct file *file) 2185 { 2186 struct tun_file *tfile = file->private_data; 2187 struct net *net = tfile->net; 2188 2189 tun_detach(tfile, true); 2190 put_net(net); 2191 2192 return 0; 2193 } 2194 2195 static const struct file_operations tun_fops = { 2196 .owner = THIS_MODULE, 2197 .llseek = no_llseek, 2198 .read = do_sync_read, 2199 .aio_read = tun_chr_aio_read, 2200 .write = do_sync_write, 2201 .aio_write = tun_chr_aio_write, 2202 .poll = tun_chr_poll, 2203 .unlocked_ioctl = tun_chr_ioctl, 2204 #ifdef CONFIG_COMPAT 2205 .compat_ioctl = tun_chr_compat_ioctl, 2206 #endif 2207 .open = tun_chr_open, 2208 .release = tun_chr_close, 2209 .fasync = tun_chr_fasync 2210 }; 2211 2212 static struct miscdevice tun_miscdev = { 2213 .minor = TUN_MINOR, 2214 .name = "tun", 2215 .nodename = "net/tun", 2216 .fops = &tun_fops, 2217 }; 2218 2219 /* ethtool interface */ 2220 2221 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2222 { 2223 cmd->supported = 0; 2224 cmd->advertising = 0; 2225 ethtool_cmd_speed_set(cmd, SPEED_10); 2226 cmd->duplex = DUPLEX_FULL; 2227 cmd->port = PORT_TP; 2228 cmd->phy_address = 0; 2229 cmd->transceiver = XCVR_INTERNAL; 2230 cmd->autoneg = AUTONEG_DISABLE; 2231 cmd->maxtxpkt = 0; 2232 cmd->maxrxpkt = 0; 2233 return 0; 2234 } 2235 2236 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2237 { 2238 struct tun_struct *tun = netdev_priv(dev); 2239 2240 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2241 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2242 2243 switch (tun->flags & TUN_TYPE_MASK) { 2244 case TUN_TUN_DEV: 2245 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2246 break; 2247 case TUN_TAP_DEV: 2248 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2249 break; 2250 } 2251 } 2252 2253 static u32 tun_get_msglevel(struct net_device *dev) 2254 { 2255 #ifdef TUN_DEBUG 2256 struct tun_struct *tun = netdev_priv(dev); 2257 return tun->debug; 2258 #else 2259 return -EOPNOTSUPP; 2260 #endif 2261 } 2262 2263 static void tun_set_msglevel(struct net_device *dev, u32 value) 2264 { 2265 #ifdef TUN_DEBUG 2266 struct tun_struct *tun = netdev_priv(dev); 2267 tun->debug = value; 2268 #endif 2269 } 2270 2271 static const struct ethtool_ops tun_ethtool_ops = { 2272 .get_settings = tun_get_settings, 2273 .get_drvinfo = tun_get_drvinfo, 2274 .get_msglevel = tun_get_msglevel, 2275 .set_msglevel = tun_set_msglevel, 2276 .get_link = ethtool_op_get_link, 2277 }; 2278 2279 2280 static int __init tun_init(void) 2281 { 2282 int ret = 0; 2283 2284 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2285 pr_info("%s\n", DRV_COPYRIGHT); 2286 2287 ret = rtnl_link_register(&tun_link_ops); 2288 if (ret) { 2289 pr_err("Can't register link_ops\n"); 2290 goto err_linkops; 2291 } 2292 2293 ret = misc_register(&tun_miscdev); 2294 if (ret) { 2295 pr_err("Can't register misc device %d\n", TUN_MINOR); 2296 goto err_misc; 2297 } 2298 return 0; 2299 err_misc: 2300 rtnl_link_unregister(&tun_link_ops); 2301 err_linkops: 2302 return ret; 2303 } 2304 2305 static void tun_cleanup(void) 2306 { 2307 misc_deregister(&tun_miscdev); 2308 rtnl_link_unregister(&tun_link_ops); 2309 } 2310 2311 /* Get an underlying socket object from tun file. Returns error unless file is 2312 * attached to a device. The returned object works like a packet socket, it 2313 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2314 * holding a reference to the file for as long as the socket is in use. */ 2315 struct socket *tun_get_socket(struct file *file) 2316 { 2317 struct tun_file *tfile; 2318 if (file->f_op != &tun_fops) 2319 return ERR_PTR(-EINVAL); 2320 tfile = file->private_data; 2321 if (!tfile) 2322 return ERR_PTR(-EBADFD); 2323 return &tfile->socket; 2324 } 2325 EXPORT_SYMBOL_GPL(tun_get_socket); 2326 2327 module_init(tun_init); 2328 module_exit(tun_cleanup); 2329 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2330 MODULE_AUTHOR(DRV_COPYRIGHT); 2331 MODULE_LICENSE("GPL"); 2332 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2333 MODULE_ALIAS("devname:net/tun"); 2334