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