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 = 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 struct net_device *dev; 413 414 tun = rtnl_dereference(tfile->tun); 415 416 if (tun && !tfile->detached) { 417 u16 index = tfile->queue_index; 418 BUG_ON(index >= tun->numqueues); 419 dev = tun->dev; 420 421 rcu_assign_pointer(tun->tfiles[index], 422 tun->tfiles[tun->numqueues - 1]); 423 ntfile = rtnl_dereference(tun->tfiles[index]); 424 ntfile->queue_index = index; 425 426 --tun->numqueues; 427 if (clean) { 428 rcu_assign_pointer(tfile->tun, NULL); 429 sock_put(&tfile->sk); 430 } else 431 tun_disable_queue(tun, tfile); 432 433 synchronize_net(); 434 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 435 /* Drop read queue */ 436 skb_queue_purge(&tfile->sk.sk_receive_queue); 437 tun_set_real_num_queues(tun); 438 } else if (tfile->detached && clean) { 439 tun = tun_enable_queue(tfile); 440 sock_put(&tfile->sk); 441 } 442 443 if (clean) { 444 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 445 netif_carrier_off(tun->dev); 446 447 if (!(tun->flags & TUN_PERSIST) && 448 tun->dev->reg_state == NETREG_REGISTERED) 449 unregister_netdevice(tun->dev); 450 } 451 452 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 453 &tfile->socket.flags)); 454 sk_release_kernel(&tfile->sk); 455 } 456 } 457 458 static void tun_detach(struct tun_file *tfile, bool clean) 459 { 460 rtnl_lock(); 461 __tun_detach(tfile, clean); 462 rtnl_unlock(); 463 } 464 465 static void tun_detach_all(struct net_device *dev) 466 { 467 struct tun_struct *tun = netdev_priv(dev); 468 struct tun_file *tfile, *tmp; 469 int i, n = tun->numqueues; 470 471 for (i = 0; i < n; i++) { 472 tfile = rtnl_dereference(tun->tfiles[i]); 473 BUG_ON(!tfile); 474 wake_up_all(&tfile->wq.wait); 475 rcu_assign_pointer(tfile->tun, NULL); 476 --tun->numqueues; 477 } 478 list_for_each_entry(tfile, &tun->disabled, next) { 479 wake_up_all(&tfile->wq.wait); 480 rcu_assign_pointer(tfile->tun, NULL); 481 } 482 BUG_ON(tun->numqueues != 0); 483 484 synchronize_net(); 485 for (i = 0; i < n; i++) { 486 tfile = rtnl_dereference(tun->tfiles[i]); 487 /* Drop read queue */ 488 skb_queue_purge(&tfile->sk.sk_receive_queue); 489 sock_put(&tfile->sk); 490 } 491 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 492 tun_enable_queue(tfile); 493 skb_queue_purge(&tfile->sk.sk_receive_queue); 494 sock_put(&tfile->sk); 495 } 496 BUG_ON(tun->numdisabled != 0); 497 498 if (tun->flags & TUN_PERSIST) 499 module_put(THIS_MODULE); 500 } 501 502 static int tun_attach(struct tun_struct *tun, struct file *file) 503 { 504 struct tun_file *tfile = file->private_data; 505 int err; 506 507 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 508 if (err < 0) 509 goto out; 510 511 err = -EINVAL; 512 if (rtnl_dereference(tfile->tun) && !tfile->detached) 513 goto out; 514 515 err = -EBUSY; 516 if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1) 517 goto out; 518 519 err = -E2BIG; 520 if (!tfile->detached && 521 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 522 goto out; 523 524 err = 0; 525 526 /* Re-attach the filter to presist device */ 527 if (tun->filter_attached == true) { 528 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 529 if (!err) 530 goto out; 531 } 532 tfile->queue_index = tun->numqueues; 533 rcu_assign_pointer(tfile->tun, tun); 534 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 535 tun->numqueues++; 536 537 if (tfile->detached) 538 tun_enable_queue(tfile); 539 else 540 sock_hold(&tfile->sk); 541 542 tun_set_real_num_queues(tun); 543 544 /* device is allowed to go away first, so no need to hold extra 545 * refcnt. 546 */ 547 548 out: 549 return err; 550 } 551 552 static struct tun_struct *__tun_get(struct tun_file *tfile) 553 { 554 struct tun_struct *tun; 555 556 rcu_read_lock(); 557 tun = rcu_dereference(tfile->tun); 558 if (tun) 559 dev_hold(tun->dev); 560 rcu_read_unlock(); 561 562 return tun; 563 } 564 565 static struct tun_struct *tun_get(struct file *file) 566 { 567 return __tun_get(file->private_data); 568 } 569 570 static void tun_put(struct tun_struct *tun) 571 { 572 dev_put(tun->dev); 573 } 574 575 /* TAP filtering */ 576 static void addr_hash_set(u32 *mask, const u8 *addr) 577 { 578 int n = ether_crc(ETH_ALEN, addr) >> 26; 579 mask[n >> 5] |= (1 << (n & 31)); 580 } 581 582 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 583 { 584 int n = ether_crc(ETH_ALEN, addr) >> 26; 585 return mask[n >> 5] & (1 << (n & 31)); 586 } 587 588 static int update_filter(struct tap_filter *filter, void __user *arg) 589 { 590 struct { u8 u[ETH_ALEN]; } *addr; 591 struct tun_filter uf; 592 int err, alen, n, nexact; 593 594 if (copy_from_user(&uf, arg, sizeof(uf))) 595 return -EFAULT; 596 597 if (!uf.count) { 598 /* Disabled */ 599 filter->count = 0; 600 return 0; 601 } 602 603 alen = ETH_ALEN * uf.count; 604 addr = kmalloc(alen, GFP_KERNEL); 605 if (!addr) 606 return -ENOMEM; 607 608 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 609 err = -EFAULT; 610 goto done; 611 } 612 613 /* The filter is updated without holding any locks. Which is 614 * perfectly safe. We disable it first and in the worst 615 * case we'll accept a few undesired packets. */ 616 filter->count = 0; 617 wmb(); 618 619 /* Use first set of addresses as an exact filter */ 620 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 621 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 622 623 nexact = n; 624 625 /* Remaining multicast addresses are hashed, 626 * unicast will leave the filter disabled. */ 627 memset(filter->mask, 0, sizeof(filter->mask)); 628 for (; n < uf.count; n++) { 629 if (!is_multicast_ether_addr(addr[n].u)) { 630 err = 0; /* no filter */ 631 goto done; 632 } 633 addr_hash_set(filter->mask, addr[n].u); 634 } 635 636 /* For ALLMULTI just set the mask to all ones. 637 * This overrides the mask populated above. */ 638 if ((uf.flags & TUN_FLT_ALLMULTI)) 639 memset(filter->mask, ~0, sizeof(filter->mask)); 640 641 /* Now enable the filter */ 642 wmb(); 643 filter->count = nexact; 644 645 /* Return the number of exact filters */ 646 err = nexact; 647 648 done: 649 kfree(addr); 650 return err; 651 } 652 653 /* Returns: 0 - drop, !=0 - accept */ 654 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 655 { 656 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 657 * at this point. */ 658 struct ethhdr *eh = (struct ethhdr *) skb->data; 659 int i; 660 661 /* Exact match */ 662 for (i = 0; i < filter->count; i++) 663 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 664 return 1; 665 666 /* Inexact match (multicast only) */ 667 if (is_multicast_ether_addr(eh->h_dest)) 668 return addr_hash_test(filter->mask, eh->h_dest); 669 670 return 0; 671 } 672 673 /* 674 * Checks whether the packet is accepted or not. 675 * Returns: 0 - drop, !=0 - accept 676 */ 677 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 678 { 679 if (!filter->count) 680 return 1; 681 682 return run_filter(filter, skb); 683 } 684 685 /* Network device part of the driver */ 686 687 static const struct ethtool_ops tun_ethtool_ops; 688 689 /* Net device detach from fd. */ 690 static void tun_net_uninit(struct net_device *dev) 691 { 692 tun_detach_all(dev); 693 } 694 695 /* Net device open. */ 696 static int tun_net_open(struct net_device *dev) 697 { 698 netif_tx_start_all_queues(dev); 699 return 0; 700 } 701 702 /* Net device close. */ 703 static int tun_net_close(struct net_device *dev) 704 { 705 netif_tx_stop_all_queues(dev); 706 return 0; 707 } 708 709 /* Net device start xmit */ 710 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 711 { 712 struct tun_struct *tun = netdev_priv(dev); 713 int txq = skb->queue_mapping; 714 struct tun_file *tfile; 715 716 rcu_read_lock(); 717 tfile = rcu_dereference(tun->tfiles[txq]); 718 719 /* Drop packet if interface is not attached */ 720 if (txq >= tun->numqueues) 721 goto drop; 722 723 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 724 725 BUG_ON(!tfile); 726 727 /* Drop if the filter does not like it. 728 * This is a noop if the filter is disabled. 729 * Filter can be enabled only for the TAP devices. */ 730 if (!check_filter(&tun->txflt, skb)) 731 goto drop; 732 733 if (tfile->socket.sk->sk_filter && 734 sk_filter(tfile->socket.sk, skb)) 735 goto drop; 736 737 /* Limit the number of packets queued by dividing txq length with the 738 * number of queues. 739 */ 740 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) 741 >= dev->tx_queue_len / tun->numqueues) 742 goto drop; 743 744 /* Orphan the skb - required as we might hang on to it 745 * for indefinite time. */ 746 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 747 goto drop; 748 skb_orphan(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 int 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 return 0; 857 } 858 859 static void tun_flow_uninit(struct tun_struct *tun) 860 { 861 del_timer_sync(&tun->flow_gc_timer); 862 tun_flow_flush(tun); 863 } 864 865 /* Initialize net device. */ 866 static void tun_net_init(struct net_device *dev) 867 { 868 struct tun_struct *tun = netdev_priv(dev); 869 870 switch (tun->flags & TUN_TYPE_MASK) { 871 case TUN_TUN_DEV: 872 dev->netdev_ops = &tun_netdev_ops; 873 874 /* Point-to-Point TUN Device */ 875 dev->hard_header_len = 0; 876 dev->addr_len = 0; 877 dev->mtu = 1500; 878 879 /* Zero header length */ 880 dev->type = ARPHRD_NONE; 881 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 882 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 883 break; 884 885 case TUN_TAP_DEV: 886 dev->netdev_ops = &tap_netdev_ops; 887 /* Ethernet TAP Device */ 888 ether_setup(dev); 889 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 890 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 891 892 eth_hw_addr_random(dev); 893 894 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 895 break; 896 } 897 } 898 899 /* Character device part */ 900 901 /* Poll */ 902 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 903 { 904 struct tun_file *tfile = file->private_data; 905 struct tun_struct *tun = __tun_get(tfile); 906 struct sock *sk; 907 unsigned int mask = 0; 908 909 if (!tun) 910 return POLLERR; 911 912 sk = tfile->socket.sk; 913 914 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 915 916 poll_wait(file, &tfile->wq.wait, wait); 917 918 if (!skb_queue_empty(&sk->sk_receive_queue)) 919 mask |= POLLIN | POLLRDNORM; 920 921 if (sock_writeable(sk) || 922 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 923 sock_writeable(sk))) 924 mask |= POLLOUT | POLLWRNORM; 925 926 if (tun->dev->reg_state != NETREG_REGISTERED) 927 mask = POLLERR; 928 929 tun_put(tun); 930 return mask; 931 } 932 933 /* prepad is the amount to reserve at front. len is length after that. 934 * linear is a hint as to how much to copy (usually headers). */ 935 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 936 size_t prepad, size_t len, 937 size_t linear, int noblock) 938 { 939 struct sock *sk = tfile->socket.sk; 940 struct sk_buff *skb; 941 int err; 942 943 /* Under a page? Don't bother with paged skb. */ 944 if (prepad + len < PAGE_SIZE || !linear) 945 linear = len; 946 947 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 948 &err); 949 if (!skb) 950 return ERR_PTR(err); 951 952 skb_reserve(skb, prepad); 953 skb_put(skb, linear); 954 skb->data_len = len - linear; 955 skb->len += len - linear; 956 957 return skb; 958 } 959 960 /* set skb frags from iovec, this can move to core network code for reuse */ 961 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, 962 int offset, size_t count) 963 { 964 int len = iov_length(from, count) - offset; 965 int copy = skb_headlen(skb); 966 int size, offset1 = 0; 967 int i = 0; 968 969 /* Skip over from offset */ 970 while (count && (offset >= from->iov_len)) { 971 offset -= from->iov_len; 972 ++from; 973 --count; 974 } 975 976 /* copy up to skb headlen */ 977 while (count && (copy > 0)) { 978 size = min_t(unsigned int, copy, from->iov_len - offset); 979 if (copy_from_user(skb->data + offset1, from->iov_base + offset, 980 size)) 981 return -EFAULT; 982 if (copy > size) { 983 ++from; 984 --count; 985 offset = 0; 986 } else 987 offset += size; 988 copy -= size; 989 offset1 += size; 990 } 991 992 if (len == offset1) 993 return 0; 994 995 while (count--) { 996 struct page *page[MAX_SKB_FRAGS]; 997 int num_pages; 998 unsigned long base; 999 unsigned long truesize; 1000 1001 len = from->iov_len - offset; 1002 if (!len) { 1003 offset = 0; 1004 ++from; 1005 continue; 1006 } 1007 base = (unsigned long)from->iov_base + offset; 1008 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; 1009 if (i + size > MAX_SKB_FRAGS) 1010 return -EMSGSIZE; 1011 num_pages = get_user_pages_fast(base, size, 0, &page[i]); 1012 if (num_pages != size) { 1013 for (i = 0; i < num_pages; i++) 1014 put_page(page[i]); 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 /* Get packet from user space buffer */ 1039 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1040 void *msg_control, const struct iovec *iv, 1041 size_t total_len, size_t count, int noblock) 1042 { 1043 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1044 struct sk_buff *skb; 1045 size_t len = total_len, align = NET_SKB_PAD; 1046 struct virtio_net_hdr gso = { 0 }; 1047 int offset = 0; 1048 int copylen; 1049 bool zerocopy = false; 1050 int err; 1051 u32 rxhash; 1052 1053 if (!(tun->flags & TUN_NO_PI)) { 1054 if ((len -= sizeof(pi)) > total_len) 1055 return -EINVAL; 1056 1057 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) 1058 return -EFAULT; 1059 offset += sizeof(pi); 1060 } 1061 1062 if (tun->flags & TUN_VNET_HDR) { 1063 if ((len -= tun->vnet_hdr_sz) > total_len) 1064 return -EINVAL; 1065 1066 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) 1067 return -EFAULT; 1068 1069 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1070 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) 1071 gso.hdr_len = gso.csum_start + gso.csum_offset + 2; 1072 1073 if (gso.hdr_len > len) 1074 return -EINVAL; 1075 offset += tun->vnet_hdr_sz; 1076 } 1077 1078 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { 1079 align += NET_IP_ALIGN; 1080 if (unlikely(len < ETH_HLEN || 1081 (gso.hdr_len && gso.hdr_len < ETH_HLEN))) 1082 return -EINVAL; 1083 } 1084 1085 if (msg_control) 1086 zerocopy = true; 1087 1088 if (zerocopy) { 1089 /* Userspace may produce vectors with count greater than 1090 * MAX_SKB_FRAGS, so we need to linearize parts of the skb 1091 * to let the rest of data to be fit in the frags. 1092 */ 1093 if (count > MAX_SKB_FRAGS) { 1094 copylen = iov_length(iv, count - MAX_SKB_FRAGS); 1095 if (copylen < offset) 1096 copylen = 0; 1097 else 1098 copylen -= offset; 1099 } else 1100 copylen = 0; 1101 /* There are 256 bytes to be copied in skb, so there is enough 1102 * room for skb expand head in case it is used. 1103 * The rest of the buffer is mapped from userspace. 1104 */ 1105 if (copylen < gso.hdr_len) 1106 copylen = gso.hdr_len; 1107 if (!copylen) 1108 copylen = GOODCOPY_LEN; 1109 } else 1110 copylen = len; 1111 1112 skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, noblock); 1113 if (IS_ERR(skb)) { 1114 if (PTR_ERR(skb) != -EAGAIN) 1115 tun->dev->stats.rx_dropped++; 1116 return PTR_ERR(skb); 1117 } 1118 1119 if (zerocopy) 1120 err = zerocopy_sg_from_iovec(skb, iv, offset, count); 1121 else 1122 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len); 1123 1124 if (err) { 1125 tun->dev->stats.rx_dropped++; 1126 kfree_skb(skb); 1127 return -EFAULT; 1128 } 1129 1130 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1131 if (!skb_partial_csum_set(skb, gso.csum_start, 1132 gso.csum_offset)) { 1133 tun->dev->stats.rx_frame_errors++; 1134 kfree_skb(skb); 1135 return -EINVAL; 1136 } 1137 } 1138 1139 switch (tun->flags & TUN_TYPE_MASK) { 1140 case TUN_TUN_DEV: 1141 if (tun->flags & TUN_NO_PI) { 1142 switch (skb->data[0] & 0xf0) { 1143 case 0x40: 1144 pi.proto = htons(ETH_P_IP); 1145 break; 1146 case 0x60: 1147 pi.proto = htons(ETH_P_IPV6); 1148 break; 1149 default: 1150 tun->dev->stats.rx_dropped++; 1151 kfree_skb(skb); 1152 return -EINVAL; 1153 } 1154 } 1155 1156 skb_reset_mac_header(skb); 1157 skb->protocol = pi.proto; 1158 skb->dev = tun->dev; 1159 break; 1160 case TUN_TAP_DEV: 1161 skb->protocol = eth_type_trans(skb, tun->dev); 1162 break; 1163 } 1164 1165 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1166 pr_debug("GSO!\n"); 1167 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1168 case VIRTIO_NET_HDR_GSO_TCPV4: 1169 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1170 break; 1171 case VIRTIO_NET_HDR_GSO_TCPV6: 1172 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1173 break; 1174 case VIRTIO_NET_HDR_GSO_UDP: 1175 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1176 break; 1177 default: 1178 tun->dev->stats.rx_frame_errors++; 1179 kfree_skb(skb); 1180 return -EINVAL; 1181 } 1182 1183 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1184 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1185 1186 skb_shinfo(skb)->gso_size = gso.gso_size; 1187 if (skb_shinfo(skb)->gso_size == 0) { 1188 tun->dev->stats.rx_frame_errors++; 1189 kfree_skb(skb); 1190 return -EINVAL; 1191 } 1192 1193 /* Header must be checked, and gso_segs computed. */ 1194 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1195 skb_shinfo(skb)->gso_segs = 0; 1196 } 1197 1198 /* copy skb_ubuf_info for callback when skb has no error */ 1199 if (zerocopy) { 1200 skb_shinfo(skb)->destructor_arg = msg_control; 1201 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1202 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1203 } 1204 1205 skb_reset_network_header(skb); 1206 rxhash = skb_get_rxhash(skb); 1207 netif_rx_ni(skb); 1208 1209 tun->dev->stats.rx_packets++; 1210 tun->dev->stats.rx_bytes += len; 1211 1212 tun_flow_update(tun, rxhash, tfile); 1213 return total_len; 1214 } 1215 1216 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 1217 unsigned long count, loff_t pos) 1218 { 1219 struct file *file = iocb->ki_filp; 1220 struct tun_struct *tun = tun_get(file); 1221 struct tun_file *tfile = file->private_data; 1222 ssize_t result; 1223 1224 if (!tun) 1225 return -EBADFD; 1226 1227 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count); 1228 1229 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count), 1230 count, file->f_flags & O_NONBLOCK); 1231 1232 tun_put(tun); 1233 return result; 1234 } 1235 1236 /* Put packet to the user space buffer */ 1237 static ssize_t tun_put_user(struct tun_struct *tun, 1238 struct tun_file *tfile, 1239 struct sk_buff *skb, 1240 const struct iovec *iv, int len) 1241 { 1242 struct tun_pi pi = { 0, skb->protocol }; 1243 ssize_t total = 0; 1244 1245 if (!(tun->flags & TUN_NO_PI)) { 1246 if ((len -= sizeof(pi)) < 0) 1247 return -EINVAL; 1248 1249 if (len < skb->len) { 1250 /* Packet will be striped */ 1251 pi.flags |= TUN_PKT_STRIP; 1252 } 1253 1254 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi))) 1255 return -EFAULT; 1256 total += sizeof(pi); 1257 } 1258 1259 if (tun->flags & TUN_VNET_HDR) { 1260 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1261 if ((len -= tun->vnet_hdr_sz) < 0) 1262 return -EINVAL; 1263 1264 if (skb_is_gso(skb)) { 1265 struct skb_shared_info *sinfo = skb_shinfo(skb); 1266 1267 /* This is a hint as to how much should be linear. */ 1268 gso.hdr_len = skb_headlen(skb); 1269 gso.gso_size = sinfo->gso_size; 1270 if (sinfo->gso_type & SKB_GSO_TCPV4) 1271 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1272 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1273 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1274 else if (sinfo->gso_type & SKB_GSO_UDP) 1275 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1276 else { 1277 pr_err("unexpected GSO type: " 1278 "0x%x, gso_size %d, hdr_len %d\n", 1279 sinfo->gso_type, gso.gso_size, 1280 gso.hdr_len); 1281 print_hex_dump(KERN_ERR, "tun: ", 1282 DUMP_PREFIX_NONE, 1283 16, 1, skb->head, 1284 min((int)gso.hdr_len, 64), true); 1285 WARN_ON_ONCE(1); 1286 return -EINVAL; 1287 } 1288 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1289 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1290 } else 1291 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1292 1293 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1294 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1295 gso.csum_start = skb_checksum_start_offset(skb); 1296 gso.csum_offset = skb->csum_offset; 1297 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1298 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1299 } /* else everything is zero */ 1300 1301 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, 1302 sizeof(gso)))) 1303 return -EFAULT; 1304 total += tun->vnet_hdr_sz; 1305 } 1306 1307 len = min_t(int, skb->len, len); 1308 1309 skb_copy_datagram_const_iovec(skb, 0, iv, total, len); 1310 total += skb->len; 1311 1312 tun->dev->stats.tx_packets++; 1313 tun->dev->stats.tx_bytes += len; 1314 1315 return total; 1316 } 1317 1318 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1319 struct kiocb *iocb, const struct iovec *iv, 1320 ssize_t len, int noblock) 1321 { 1322 DECLARE_WAITQUEUE(wait, current); 1323 struct sk_buff *skb; 1324 ssize_t ret = 0; 1325 1326 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1327 1328 if (unlikely(!noblock)) 1329 add_wait_queue(&tfile->wq.wait, &wait); 1330 while (len) { 1331 current->state = TASK_INTERRUPTIBLE; 1332 1333 /* Read frames from the queue */ 1334 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) { 1335 if (noblock) { 1336 ret = -EAGAIN; 1337 break; 1338 } 1339 if (signal_pending(current)) { 1340 ret = -ERESTARTSYS; 1341 break; 1342 } 1343 if (tun->dev->reg_state != NETREG_REGISTERED) { 1344 ret = -EIO; 1345 break; 1346 } 1347 1348 /* Nothing to read, let's sleep */ 1349 schedule(); 1350 continue; 1351 } 1352 1353 ret = tun_put_user(tun, tfile, skb, iv, len); 1354 kfree_skb(skb); 1355 break; 1356 } 1357 1358 current->state = TASK_RUNNING; 1359 if (unlikely(!noblock)) 1360 remove_wait_queue(&tfile->wq.wait, &wait); 1361 1362 return ret; 1363 } 1364 1365 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 1366 unsigned long count, loff_t pos) 1367 { 1368 struct file *file = iocb->ki_filp; 1369 struct tun_file *tfile = file->private_data; 1370 struct tun_struct *tun = __tun_get(tfile); 1371 ssize_t len, ret; 1372 1373 if (!tun) 1374 return -EBADFD; 1375 len = iov_length(iv, count); 1376 if (len < 0) { 1377 ret = -EINVAL; 1378 goto out; 1379 } 1380 1381 ret = tun_do_read(tun, tfile, iocb, iv, len, 1382 file->f_flags & O_NONBLOCK); 1383 ret = min_t(ssize_t, ret, len); 1384 out: 1385 tun_put(tun); 1386 return ret; 1387 } 1388 1389 static void tun_free_netdev(struct net_device *dev) 1390 { 1391 struct tun_struct *tun = netdev_priv(dev); 1392 1393 BUG_ON(!(list_empty(&tun->disabled))); 1394 tun_flow_uninit(tun); 1395 security_tun_dev_free_security(tun->security); 1396 free_netdev(dev); 1397 } 1398 1399 static void tun_setup(struct net_device *dev) 1400 { 1401 struct tun_struct *tun = netdev_priv(dev); 1402 1403 tun->owner = INVALID_UID; 1404 tun->group = INVALID_GID; 1405 1406 dev->ethtool_ops = &tun_ethtool_ops; 1407 dev->destructor = tun_free_netdev; 1408 } 1409 1410 /* Trivial set of netlink ops to allow deleting tun or tap 1411 * device with netlink. 1412 */ 1413 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1414 { 1415 return -EINVAL; 1416 } 1417 1418 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1419 .kind = DRV_NAME, 1420 .priv_size = sizeof(struct tun_struct), 1421 .setup = tun_setup, 1422 .validate = tun_validate, 1423 }; 1424 1425 static void tun_sock_write_space(struct sock *sk) 1426 { 1427 struct tun_file *tfile; 1428 wait_queue_head_t *wqueue; 1429 1430 if (!sock_writeable(sk)) 1431 return; 1432 1433 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1434 return; 1435 1436 wqueue = sk_sleep(sk); 1437 if (wqueue && waitqueue_active(wqueue)) 1438 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1439 POLLWRNORM | POLLWRBAND); 1440 1441 tfile = container_of(sk, struct tun_file, sk); 1442 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1443 } 1444 1445 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1446 struct msghdr *m, size_t total_len) 1447 { 1448 int ret; 1449 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1450 struct tun_struct *tun = __tun_get(tfile); 1451 1452 if (!tun) 1453 return -EBADFD; 1454 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len, 1455 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); 1456 tun_put(tun); 1457 return ret; 1458 } 1459 1460 1461 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1462 struct msghdr *m, size_t total_len, 1463 int flags) 1464 { 1465 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1466 struct tun_struct *tun = __tun_get(tfile); 1467 int ret; 1468 1469 if (!tun) 1470 return -EBADFD; 1471 1472 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) 1473 return -EINVAL; 1474 ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len, 1475 flags & MSG_DONTWAIT); 1476 if (ret > total_len) { 1477 m->msg_flags |= MSG_TRUNC; 1478 ret = flags & MSG_TRUNC ? ret : total_len; 1479 } 1480 tun_put(tun); 1481 return ret; 1482 } 1483 1484 static int tun_release(struct socket *sock) 1485 { 1486 if (sock->sk) 1487 sock_put(sock->sk); 1488 return 0; 1489 } 1490 1491 /* Ops structure to mimic raw sockets with tun */ 1492 static const struct proto_ops tun_socket_ops = { 1493 .sendmsg = tun_sendmsg, 1494 .recvmsg = tun_recvmsg, 1495 .release = tun_release, 1496 }; 1497 1498 static struct proto tun_proto = { 1499 .name = "tun", 1500 .owner = THIS_MODULE, 1501 .obj_size = sizeof(struct tun_file), 1502 }; 1503 1504 static int tun_flags(struct tun_struct *tun) 1505 { 1506 int flags = 0; 1507 1508 if (tun->flags & TUN_TUN_DEV) 1509 flags |= IFF_TUN; 1510 else 1511 flags |= IFF_TAP; 1512 1513 if (tun->flags & TUN_NO_PI) 1514 flags |= IFF_NO_PI; 1515 1516 /* This flag has no real effect. We track the value for backwards 1517 * compatibility. 1518 */ 1519 if (tun->flags & TUN_ONE_QUEUE) 1520 flags |= IFF_ONE_QUEUE; 1521 1522 if (tun->flags & TUN_VNET_HDR) 1523 flags |= IFF_VNET_HDR; 1524 1525 if (tun->flags & TUN_TAP_MQ) 1526 flags |= IFF_MULTI_QUEUE; 1527 1528 return flags; 1529 } 1530 1531 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1532 char *buf) 1533 { 1534 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1535 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1536 } 1537 1538 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1539 char *buf) 1540 { 1541 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1542 return uid_valid(tun->owner)? 1543 sprintf(buf, "%u\n", 1544 from_kuid_munged(current_user_ns(), tun->owner)): 1545 sprintf(buf, "-1\n"); 1546 } 1547 1548 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1549 char *buf) 1550 { 1551 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1552 return gid_valid(tun->group) ? 1553 sprintf(buf, "%u\n", 1554 from_kgid_munged(current_user_ns(), tun->group)): 1555 sprintf(buf, "-1\n"); 1556 } 1557 1558 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1559 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1560 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1561 1562 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1563 { 1564 struct tun_struct *tun; 1565 struct tun_file *tfile = file->private_data; 1566 struct net_device *dev; 1567 int err; 1568 1569 if (tfile->detached) 1570 return -EINVAL; 1571 1572 dev = __dev_get_by_name(net, ifr->ifr_name); 1573 if (dev) { 1574 if (ifr->ifr_flags & IFF_TUN_EXCL) 1575 return -EBUSY; 1576 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1577 tun = netdev_priv(dev); 1578 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1579 tun = netdev_priv(dev); 1580 else 1581 return -EINVAL; 1582 1583 if (tun_not_capable(tun)) 1584 return -EPERM; 1585 err = security_tun_dev_open(tun->security); 1586 if (err < 0) 1587 return err; 1588 1589 err = tun_attach(tun, file); 1590 if (err < 0) 1591 return err; 1592 1593 if (tun->flags & TUN_TAP_MQ && 1594 (tun->numqueues + tun->numdisabled > 1)) 1595 return err; 1596 } 1597 else { 1598 char *name; 1599 unsigned long flags = 0; 1600 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1601 MAX_TAP_QUEUES : 1; 1602 1603 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1604 return -EPERM; 1605 err = security_tun_dev_create(); 1606 if (err < 0) 1607 return err; 1608 1609 /* Set dev type */ 1610 if (ifr->ifr_flags & IFF_TUN) { 1611 /* TUN device */ 1612 flags |= TUN_TUN_DEV; 1613 name = "tun%d"; 1614 } else if (ifr->ifr_flags & IFF_TAP) { 1615 /* TAP device */ 1616 flags |= TUN_TAP_DEV; 1617 name = "tap%d"; 1618 } else 1619 return -EINVAL; 1620 1621 if (*ifr->ifr_name) 1622 name = ifr->ifr_name; 1623 1624 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1625 tun_setup, queues, queues); 1626 1627 if (!dev) 1628 return -ENOMEM; 1629 1630 dev_net_set(dev, net); 1631 dev->rtnl_link_ops = &tun_link_ops; 1632 1633 tun = netdev_priv(dev); 1634 tun->dev = dev; 1635 tun->flags = flags; 1636 tun->txflt.count = 0; 1637 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1638 1639 tun->filter_attached = false; 1640 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1641 1642 spin_lock_init(&tun->lock); 1643 1644 err = security_tun_dev_alloc_security(&tun->security); 1645 if (err < 0) 1646 goto err_free_dev; 1647 1648 tun_net_init(dev); 1649 1650 err = tun_flow_init(tun); 1651 if (err < 0) 1652 goto err_free_dev; 1653 1654 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1655 TUN_USER_FEATURES; 1656 dev->features = dev->hw_features; 1657 1658 INIT_LIST_HEAD(&tun->disabled); 1659 err = tun_attach(tun, file); 1660 if (err < 0) 1661 goto err_free_dev; 1662 1663 err = register_netdevice(tun->dev); 1664 if (err < 0) 1665 goto err_free_dev; 1666 1667 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1668 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1669 device_create_file(&tun->dev->dev, &dev_attr_group)) 1670 pr_err("Failed to create tun sysfs files\n"); 1671 } 1672 1673 netif_carrier_on(tun->dev); 1674 1675 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1676 1677 if (ifr->ifr_flags & IFF_NO_PI) 1678 tun->flags |= TUN_NO_PI; 1679 else 1680 tun->flags &= ~TUN_NO_PI; 1681 1682 /* This flag has no real effect. We track the value for backwards 1683 * compatibility. 1684 */ 1685 if (ifr->ifr_flags & IFF_ONE_QUEUE) 1686 tun->flags |= TUN_ONE_QUEUE; 1687 else 1688 tun->flags &= ~TUN_ONE_QUEUE; 1689 1690 if (ifr->ifr_flags & IFF_VNET_HDR) 1691 tun->flags |= TUN_VNET_HDR; 1692 else 1693 tun->flags &= ~TUN_VNET_HDR; 1694 1695 if (ifr->ifr_flags & IFF_MULTI_QUEUE) 1696 tun->flags |= TUN_TAP_MQ; 1697 else 1698 tun->flags &= ~TUN_TAP_MQ; 1699 1700 /* Make sure persistent devices do not get stuck in 1701 * xoff state. 1702 */ 1703 if (netif_running(tun->dev)) 1704 netif_tx_wake_all_queues(tun->dev); 1705 1706 strcpy(ifr->ifr_name, tun->dev->name); 1707 return 0; 1708 1709 err_free_dev: 1710 free_netdev(dev); 1711 return err; 1712 } 1713 1714 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1715 struct ifreq *ifr) 1716 { 1717 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1718 1719 strcpy(ifr->ifr_name, tun->dev->name); 1720 1721 ifr->ifr_flags = tun_flags(tun); 1722 1723 } 1724 1725 /* This is like a cut-down ethtool ops, except done via tun fd so no 1726 * privs required. */ 1727 static int set_offload(struct tun_struct *tun, unsigned long arg) 1728 { 1729 netdev_features_t features = 0; 1730 1731 if (arg & TUN_F_CSUM) { 1732 features |= NETIF_F_HW_CSUM; 1733 arg &= ~TUN_F_CSUM; 1734 1735 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1736 if (arg & TUN_F_TSO_ECN) { 1737 features |= NETIF_F_TSO_ECN; 1738 arg &= ~TUN_F_TSO_ECN; 1739 } 1740 if (arg & TUN_F_TSO4) 1741 features |= NETIF_F_TSO; 1742 if (arg & TUN_F_TSO6) 1743 features |= NETIF_F_TSO6; 1744 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1745 } 1746 1747 if (arg & TUN_F_UFO) { 1748 features |= NETIF_F_UFO; 1749 arg &= ~TUN_F_UFO; 1750 } 1751 } 1752 1753 /* This gives the user a way to test for new features in future by 1754 * trying to set them. */ 1755 if (arg) 1756 return -EINVAL; 1757 1758 tun->set_features = features; 1759 netdev_update_features(tun->dev); 1760 1761 return 0; 1762 } 1763 1764 static void tun_detach_filter(struct tun_struct *tun, int n) 1765 { 1766 int i; 1767 struct tun_file *tfile; 1768 1769 for (i = 0; i < n; i++) { 1770 tfile = rtnl_dereference(tun->tfiles[i]); 1771 sk_detach_filter(tfile->socket.sk); 1772 } 1773 1774 tun->filter_attached = false; 1775 } 1776 1777 static int tun_attach_filter(struct tun_struct *tun) 1778 { 1779 int i, ret = 0; 1780 struct tun_file *tfile; 1781 1782 for (i = 0; i < tun->numqueues; i++) { 1783 tfile = rtnl_dereference(tun->tfiles[i]); 1784 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1785 if (ret) { 1786 tun_detach_filter(tun, i); 1787 return ret; 1788 } 1789 } 1790 1791 tun->filter_attached = true; 1792 return ret; 1793 } 1794 1795 static void tun_set_sndbuf(struct tun_struct *tun) 1796 { 1797 struct tun_file *tfile; 1798 int i; 1799 1800 for (i = 0; i < tun->numqueues; i++) { 1801 tfile = rtnl_dereference(tun->tfiles[i]); 1802 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1803 } 1804 } 1805 1806 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1807 { 1808 struct tun_file *tfile = file->private_data; 1809 struct tun_struct *tun; 1810 int ret = 0; 1811 1812 rtnl_lock(); 1813 1814 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1815 tun = tfile->detached; 1816 if (!tun) { 1817 ret = -EINVAL; 1818 goto unlock; 1819 } 1820 ret = security_tun_dev_attach_queue(tun->security); 1821 if (ret < 0) 1822 goto unlock; 1823 ret = tun_attach(tun, file); 1824 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1825 tun = rtnl_dereference(tfile->tun); 1826 if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) 1827 ret = -EINVAL; 1828 else 1829 __tun_detach(tfile, false); 1830 } else 1831 ret = -EINVAL; 1832 1833 unlock: 1834 rtnl_unlock(); 1835 return ret; 1836 } 1837 1838 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1839 unsigned long arg, int ifreq_len) 1840 { 1841 struct tun_file *tfile = file->private_data; 1842 struct tun_struct *tun; 1843 void __user* argp = (void __user*)arg; 1844 struct ifreq ifr; 1845 kuid_t owner; 1846 kgid_t group; 1847 int sndbuf; 1848 int vnet_hdr_sz; 1849 int ret; 1850 1851 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1852 if (copy_from_user(&ifr, argp, ifreq_len)) 1853 return -EFAULT; 1854 } else { 1855 memset(&ifr, 0, sizeof(ifr)); 1856 } 1857 if (cmd == TUNGETFEATURES) { 1858 /* Currently this just means: "what IFF flags are valid?". 1859 * This is needed because we never checked for invalid flags on 1860 * TUNSETIFF. */ 1861 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | 1862 IFF_VNET_HDR | IFF_MULTI_QUEUE, 1863 (unsigned int __user*)argp); 1864 } else if (cmd == TUNSETQUEUE) 1865 return tun_set_queue(file, &ifr); 1866 1867 ret = 0; 1868 rtnl_lock(); 1869 1870 tun = __tun_get(tfile); 1871 if (cmd == TUNSETIFF && !tun) { 1872 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1873 1874 ret = tun_set_iff(tfile->net, file, &ifr); 1875 1876 if (ret) 1877 goto unlock; 1878 1879 if (copy_to_user(argp, &ifr, ifreq_len)) 1880 ret = -EFAULT; 1881 goto unlock; 1882 } 1883 1884 ret = -EBADFD; 1885 if (!tun) 1886 goto unlock; 1887 1888 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1889 1890 ret = 0; 1891 switch (cmd) { 1892 case TUNGETIFF: 1893 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1894 1895 if (copy_to_user(argp, &ifr, ifreq_len)) 1896 ret = -EFAULT; 1897 break; 1898 1899 case TUNSETNOCSUM: 1900 /* Disable/Enable checksum */ 1901 1902 /* [unimplemented] */ 1903 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1904 arg ? "disabled" : "enabled"); 1905 break; 1906 1907 case TUNSETPERSIST: 1908 /* Disable/Enable persist mode. Keep an extra reference to the 1909 * module to prevent the module being unprobed. 1910 */ 1911 if (arg && !(tun->flags & TUN_PERSIST)) { 1912 tun->flags |= TUN_PERSIST; 1913 __module_get(THIS_MODULE); 1914 } 1915 if (!arg && (tun->flags & TUN_PERSIST)) { 1916 tun->flags &= ~TUN_PERSIST; 1917 module_put(THIS_MODULE); 1918 } 1919 1920 tun_debug(KERN_INFO, tun, "persist %s\n", 1921 arg ? "enabled" : "disabled"); 1922 break; 1923 1924 case TUNSETOWNER: 1925 /* Set owner of the device */ 1926 owner = make_kuid(current_user_ns(), arg); 1927 if (!uid_valid(owner)) { 1928 ret = -EINVAL; 1929 break; 1930 } 1931 tun->owner = owner; 1932 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1933 from_kuid(&init_user_ns, tun->owner)); 1934 break; 1935 1936 case TUNSETGROUP: 1937 /* Set group of the device */ 1938 group = make_kgid(current_user_ns(), arg); 1939 if (!gid_valid(group)) { 1940 ret = -EINVAL; 1941 break; 1942 } 1943 tun->group = group; 1944 tun_debug(KERN_INFO, tun, "group set to %u\n", 1945 from_kgid(&init_user_ns, tun->group)); 1946 break; 1947 1948 case TUNSETLINK: 1949 /* Only allow setting the type when the interface is down */ 1950 if (tun->dev->flags & IFF_UP) { 1951 tun_debug(KERN_INFO, tun, 1952 "Linktype set failed because interface is up\n"); 1953 ret = -EBUSY; 1954 } else { 1955 tun->dev->type = (int) arg; 1956 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1957 tun->dev->type); 1958 ret = 0; 1959 } 1960 break; 1961 1962 #ifdef TUN_DEBUG 1963 case TUNSETDEBUG: 1964 tun->debug = arg; 1965 break; 1966 #endif 1967 case TUNSETOFFLOAD: 1968 ret = set_offload(tun, arg); 1969 break; 1970 1971 case TUNSETTXFILTER: 1972 /* Can be set only for TAPs */ 1973 ret = -EINVAL; 1974 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 1975 break; 1976 ret = update_filter(&tun->txflt, (void __user *)arg); 1977 break; 1978 1979 case SIOCGIFHWADDR: 1980 /* Get hw address */ 1981 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 1982 ifr.ifr_hwaddr.sa_family = tun->dev->type; 1983 if (copy_to_user(argp, &ifr, ifreq_len)) 1984 ret = -EFAULT; 1985 break; 1986 1987 case SIOCSIFHWADDR: 1988 /* Set hw address */ 1989 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 1990 ifr.ifr_hwaddr.sa_data); 1991 1992 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 1993 break; 1994 1995 case TUNGETSNDBUF: 1996 sndbuf = tfile->socket.sk->sk_sndbuf; 1997 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 1998 ret = -EFAULT; 1999 break; 2000 2001 case TUNSETSNDBUF: 2002 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2003 ret = -EFAULT; 2004 break; 2005 } 2006 2007 tun->sndbuf = sndbuf; 2008 tun_set_sndbuf(tun); 2009 break; 2010 2011 case TUNGETVNETHDRSZ: 2012 vnet_hdr_sz = tun->vnet_hdr_sz; 2013 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2014 ret = -EFAULT; 2015 break; 2016 2017 case TUNSETVNETHDRSZ: 2018 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2019 ret = -EFAULT; 2020 break; 2021 } 2022 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2023 ret = -EINVAL; 2024 break; 2025 } 2026 2027 tun->vnet_hdr_sz = vnet_hdr_sz; 2028 break; 2029 2030 case TUNATTACHFILTER: 2031 /* Can be set only for TAPs */ 2032 ret = -EINVAL; 2033 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2034 break; 2035 ret = -EFAULT; 2036 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2037 break; 2038 2039 ret = tun_attach_filter(tun); 2040 break; 2041 2042 case TUNDETACHFILTER: 2043 /* Can be set only for TAPs */ 2044 ret = -EINVAL; 2045 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2046 break; 2047 ret = 0; 2048 tun_detach_filter(tun, tun->numqueues); 2049 break; 2050 2051 default: 2052 ret = -EINVAL; 2053 break; 2054 } 2055 2056 unlock: 2057 rtnl_unlock(); 2058 if (tun) 2059 tun_put(tun); 2060 return ret; 2061 } 2062 2063 static long tun_chr_ioctl(struct file *file, 2064 unsigned int cmd, unsigned long arg) 2065 { 2066 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2067 } 2068 2069 #ifdef CONFIG_COMPAT 2070 static long tun_chr_compat_ioctl(struct file *file, 2071 unsigned int cmd, unsigned long arg) 2072 { 2073 switch (cmd) { 2074 case TUNSETIFF: 2075 case TUNGETIFF: 2076 case TUNSETTXFILTER: 2077 case TUNGETSNDBUF: 2078 case TUNSETSNDBUF: 2079 case SIOCGIFHWADDR: 2080 case SIOCSIFHWADDR: 2081 arg = (unsigned long)compat_ptr(arg); 2082 break; 2083 default: 2084 arg = (compat_ulong_t)arg; 2085 break; 2086 } 2087 2088 /* 2089 * compat_ifreq is shorter than ifreq, so we must not access beyond 2090 * the end of that structure. All fields that are used in this 2091 * driver are compatible though, we don't need to convert the 2092 * contents. 2093 */ 2094 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2095 } 2096 #endif /* CONFIG_COMPAT */ 2097 2098 static int tun_chr_fasync(int fd, struct file *file, int on) 2099 { 2100 struct tun_file *tfile = file->private_data; 2101 int ret; 2102 2103 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2104 goto out; 2105 2106 if (on) { 2107 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2108 if (ret) 2109 goto out; 2110 tfile->flags |= TUN_FASYNC; 2111 } else 2112 tfile->flags &= ~TUN_FASYNC; 2113 ret = 0; 2114 out: 2115 return ret; 2116 } 2117 2118 static int tun_chr_open(struct inode *inode, struct file * file) 2119 { 2120 struct tun_file *tfile; 2121 2122 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2123 2124 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2125 &tun_proto); 2126 if (!tfile) 2127 return -ENOMEM; 2128 rcu_assign_pointer(tfile->tun, NULL); 2129 tfile->net = get_net(current->nsproxy->net_ns); 2130 tfile->flags = 0; 2131 2132 rcu_assign_pointer(tfile->socket.wq, &tfile->wq); 2133 init_waitqueue_head(&tfile->wq.wait); 2134 2135 tfile->socket.file = file; 2136 tfile->socket.ops = &tun_socket_ops; 2137 2138 sock_init_data(&tfile->socket, &tfile->sk); 2139 sk_change_net(&tfile->sk, tfile->net); 2140 2141 tfile->sk.sk_write_space = tun_sock_write_space; 2142 tfile->sk.sk_sndbuf = INT_MAX; 2143 2144 file->private_data = tfile; 2145 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2146 INIT_LIST_HEAD(&tfile->next); 2147 2148 return 0; 2149 } 2150 2151 static int tun_chr_close(struct inode *inode, struct file *file) 2152 { 2153 struct tun_file *tfile = file->private_data; 2154 struct net *net = tfile->net; 2155 2156 tun_detach(tfile, true); 2157 put_net(net); 2158 2159 return 0; 2160 } 2161 2162 static const struct file_operations tun_fops = { 2163 .owner = THIS_MODULE, 2164 .llseek = no_llseek, 2165 .read = do_sync_read, 2166 .aio_read = tun_chr_aio_read, 2167 .write = do_sync_write, 2168 .aio_write = tun_chr_aio_write, 2169 .poll = tun_chr_poll, 2170 .unlocked_ioctl = tun_chr_ioctl, 2171 #ifdef CONFIG_COMPAT 2172 .compat_ioctl = tun_chr_compat_ioctl, 2173 #endif 2174 .open = tun_chr_open, 2175 .release = tun_chr_close, 2176 .fasync = tun_chr_fasync 2177 }; 2178 2179 static struct miscdevice tun_miscdev = { 2180 .minor = TUN_MINOR, 2181 .name = "tun", 2182 .nodename = "net/tun", 2183 .fops = &tun_fops, 2184 }; 2185 2186 /* ethtool interface */ 2187 2188 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2189 { 2190 cmd->supported = 0; 2191 cmd->advertising = 0; 2192 ethtool_cmd_speed_set(cmd, SPEED_10); 2193 cmd->duplex = DUPLEX_FULL; 2194 cmd->port = PORT_TP; 2195 cmd->phy_address = 0; 2196 cmd->transceiver = XCVR_INTERNAL; 2197 cmd->autoneg = AUTONEG_DISABLE; 2198 cmd->maxtxpkt = 0; 2199 cmd->maxrxpkt = 0; 2200 return 0; 2201 } 2202 2203 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2204 { 2205 struct tun_struct *tun = netdev_priv(dev); 2206 2207 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2208 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2209 2210 switch (tun->flags & TUN_TYPE_MASK) { 2211 case TUN_TUN_DEV: 2212 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2213 break; 2214 case TUN_TAP_DEV: 2215 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2216 break; 2217 } 2218 } 2219 2220 static u32 tun_get_msglevel(struct net_device *dev) 2221 { 2222 #ifdef TUN_DEBUG 2223 struct tun_struct *tun = netdev_priv(dev); 2224 return tun->debug; 2225 #else 2226 return -EOPNOTSUPP; 2227 #endif 2228 } 2229 2230 static void tun_set_msglevel(struct net_device *dev, u32 value) 2231 { 2232 #ifdef TUN_DEBUG 2233 struct tun_struct *tun = netdev_priv(dev); 2234 tun->debug = value; 2235 #endif 2236 } 2237 2238 static const struct ethtool_ops tun_ethtool_ops = { 2239 .get_settings = tun_get_settings, 2240 .get_drvinfo = tun_get_drvinfo, 2241 .get_msglevel = tun_get_msglevel, 2242 .set_msglevel = tun_set_msglevel, 2243 .get_link = ethtool_op_get_link, 2244 }; 2245 2246 2247 static int __init tun_init(void) 2248 { 2249 int ret = 0; 2250 2251 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2252 pr_info("%s\n", DRV_COPYRIGHT); 2253 2254 ret = rtnl_link_register(&tun_link_ops); 2255 if (ret) { 2256 pr_err("Can't register link_ops\n"); 2257 goto err_linkops; 2258 } 2259 2260 ret = misc_register(&tun_miscdev); 2261 if (ret) { 2262 pr_err("Can't register misc device %d\n", TUN_MINOR); 2263 goto err_misc; 2264 } 2265 return 0; 2266 err_misc: 2267 rtnl_link_unregister(&tun_link_ops); 2268 err_linkops: 2269 return ret; 2270 } 2271 2272 static void tun_cleanup(void) 2273 { 2274 misc_deregister(&tun_miscdev); 2275 rtnl_link_unregister(&tun_link_ops); 2276 } 2277 2278 /* Get an underlying socket object from tun file. Returns error unless file is 2279 * attached to a device. The returned object works like a packet socket, it 2280 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2281 * holding a reference to the file for as long as the socket is in use. */ 2282 struct socket *tun_get_socket(struct file *file) 2283 { 2284 struct tun_file *tfile; 2285 if (file->f_op != &tun_fops) 2286 return ERR_PTR(-EINVAL); 2287 tfile = file->private_data; 2288 if (!tfile) 2289 return ERR_PTR(-EBADFD); 2290 return &tfile->socket; 2291 } 2292 EXPORT_SYMBOL_GPL(tun_get_socket); 2293 2294 module_init(tun_init); 2295 module_exit(tun_cleanup); 2296 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2297 MODULE_AUTHOR(DRV_COPYRIGHT); 2298 MODULE_LICENSE("GPL"); 2299 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2300 MODULE_ALIAS("devname:net/tun"); 2301