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