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