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