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/if_vlan.h> 64 #include <linux/crc32.h> 65 #include <linux/nsproxy.h> 66 #include <linux/virtio_net.h> 67 #include <linux/rcupdate.h> 68 #include <net/net_namespace.h> 69 #include <net/netns/generic.h> 70 #include <net/rtnetlink.h> 71 #include <net/sock.h> 72 73 #include <asm/uaccess.h> 74 75 /* Uncomment to enable debugging */ 76 /* #define TUN_DEBUG 1 */ 77 78 #ifdef TUN_DEBUG 79 static int debug; 80 81 #define tun_debug(level, tun, fmt, args...) \ 82 do { \ 83 if (tun->debug) \ 84 netdev_printk(level, tun->dev, fmt, ##args); \ 85 } while (0) 86 #define DBG1(level, fmt, args...) \ 87 do { \ 88 if (debug == 2) \ 89 printk(level fmt, ##args); \ 90 } while (0) 91 #else 92 #define tun_debug(level, tun, fmt, args...) \ 93 do { \ 94 if (0) \ 95 netdev_printk(level, tun->dev, fmt, ##args); \ 96 } while (0) 97 #define DBG1(level, fmt, args...) \ 98 do { \ 99 if (0) \ 100 printk(level fmt, ##args); \ 101 } while (0) 102 #endif 103 104 #define GOODCOPY_LEN 128 105 106 #define FLT_EXACT_COUNT 8 107 struct tap_filter { 108 unsigned int count; /* Number of addrs. Zero means disabled */ 109 u32 mask[2]; /* Mask of the hashed addrs */ 110 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 111 }; 112 113 /* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for 114 * the netdevice to be fit in one page. So we can make sure the success of 115 * memory allocation. TODO: increase the limit. */ 116 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES 117 #define MAX_TAP_FLOWS 4096 118 119 #define TUN_FLOW_EXPIRE (3 * HZ) 120 121 /* A tun_file connects an open character device to a tuntap netdevice. It 122 * also contains all socket related structures (except sock_fprog and tap_filter) 123 * to serve as one transmit queue for tuntap device. The sock_fprog and 124 * tap_filter were kept in tun_struct since they were used for filtering for the 125 * netdevice not for a specific queue (at least I didn't see the requirement for 126 * this). 127 * 128 * RCU usage: 129 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 130 * other can only be read while rcu_read_lock or rtnl_lock is held. 131 */ 132 struct tun_file { 133 struct sock sk; 134 struct socket socket; 135 struct socket_wq wq; 136 struct tun_struct __rcu *tun; 137 struct net *net; 138 struct fasync_struct *fasync; 139 /* only used for fasnyc */ 140 unsigned int flags; 141 union { 142 u16 queue_index; 143 unsigned int ifindex; 144 }; 145 struct list_head next; 146 struct tun_struct *detached; 147 }; 148 149 struct tun_flow_entry { 150 struct hlist_node hash_link; 151 struct rcu_head rcu; 152 struct tun_struct *tun; 153 154 u32 rxhash; 155 u32 rps_rxhash; 156 int queue_index; 157 unsigned long updated; 158 }; 159 160 #define TUN_NUM_FLOW_ENTRIES 1024 161 162 /* Since the socket were moved to tun_file, to preserve the behavior of persist 163 * device, socket filter, sndbuf and vnet header size were restore when the 164 * file were attached to a persist device. 165 */ 166 struct tun_struct { 167 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 168 unsigned int numqueues; 169 unsigned int flags; 170 kuid_t owner; 171 kgid_t group; 172 173 struct net_device *dev; 174 netdev_features_t set_features; 175 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 176 NETIF_F_TSO6|NETIF_F_UFO) 177 178 int vnet_hdr_sz; 179 int sndbuf; 180 struct tap_filter txflt; 181 struct sock_fprog fprog; 182 /* protected by rtnl lock */ 183 bool filter_attached; 184 #ifdef TUN_DEBUG 185 int debug; 186 #endif 187 spinlock_t lock; 188 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 189 struct timer_list flow_gc_timer; 190 unsigned long ageing_time; 191 unsigned int numdisabled; 192 struct list_head disabled; 193 void *security; 194 u32 flow_count; 195 }; 196 197 static inline u32 tun_hashfn(u32 rxhash) 198 { 199 return rxhash & 0x3ff; 200 } 201 202 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 203 { 204 struct tun_flow_entry *e; 205 206 hlist_for_each_entry_rcu(e, head, hash_link) { 207 if (e->rxhash == rxhash) 208 return e; 209 } 210 return NULL; 211 } 212 213 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 214 struct hlist_head *head, 215 u32 rxhash, u16 queue_index) 216 { 217 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 218 219 if (e) { 220 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 221 rxhash, queue_index); 222 e->updated = jiffies; 223 e->rxhash = rxhash; 224 e->rps_rxhash = 0; 225 e->queue_index = queue_index; 226 e->tun = tun; 227 hlist_add_head_rcu(&e->hash_link, head); 228 ++tun->flow_count; 229 } 230 return e; 231 } 232 233 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 234 { 235 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 236 e->rxhash, e->queue_index); 237 sock_rps_reset_flow_hash(e->rps_rxhash); 238 hlist_del_rcu(&e->hash_link); 239 kfree_rcu(e, rcu); 240 --tun->flow_count; 241 } 242 243 static void tun_flow_flush(struct tun_struct *tun) 244 { 245 int i; 246 247 spin_lock_bh(&tun->lock); 248 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 249 struct tun_flow_entry *e; 250 struct hlist_node *n; 251 252 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 253 tun_flow_delete(tun, e); 254 } 255 spin_unlock_bh(&tun->lock); 256 } 257 258 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 259 { 260 int i; 261 262 spin_lock_bh(&tun->lock); 263 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 264 struct tun_flow_entry *e; 265 struct hlist_node *n; 266 267 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 268 if (e->queue_index == queue_index) 269 tun_flow_delete(tun, e); 270 } 271 } 272 spin_unlock_bh(&tun->lock); 273 } 274 275 static void tun_flow_cleanup(unsigned long data) 276 { 277 struct tun_struct *tun = (struct tun_struct *)data; 278 unsigned long delay = tun->ageing_time; 279 unsigned long next_timer = jiffies + delay; 280 unsigned long count = 0; 281 int i; 282 283 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 284 285 spin_lock_bh(&tun->lock); 286 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 287 struct tun_flow_entry *e; 288 struct hlist_node *n; 289 290 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 291 unsigned long this_timer; 292 count++; 293 this_timer = e->updated + delay; 294 if (time_before_eq(this_timer, jiffies)) 295 tun_flow_delete(tun, e); 296 else if (time_before(this_timer, next_timer)) 297 next_timer = this_timer; 298 } 299 } 300 301 if (count) 302 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 303 spin_unlock_bh(&tun->lock); 304 } 305 306 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 307 struct tun_file *tfile) 308 { 309 struct hlist_head *head; 310 struct tun_flow_entry *e; 311 unsigned long delay = tun->ageing_time; 312 u16 queue_index = tfile->queue_index; 313 314 if (!rxhash) 315 return; 316 else 317 head = &tun->flows[tun_hashfn(rxhash)]; 318 319 rcu_read_lock(); 320 321 /* We may get a very small possibility of OOO during switching, not 322 * worth to optimize.*/ 323 if (tun->numqueues == 1 || tfile->detached) 324 goto unlock; 325 326 e = tun_flow_find(head, rxhash); 327 if (likely(e)) { 328 /* TODO: keep queueing to old queue until it's empty? */ 329 e->queue_index = queue_index; 330 e->updated = jiffies; 331 sock_rps_record_flow_hash(e->rps_rxhash); 332 } else { 333 spin_lock_bh(&tun->lock); 334 if (!tun_flow_find(head, rxhash) && 335 tun->flow_count < MAX_TAP_FLOWS) 336 tun_flow_create(tun, head, rxhash, queue_index); 337 338 if (!timer_pending(&tun->flow_gc_timer)) 339 mod_timer(&tun->flow_gc_timer, 340 round_jiffies_up(jiffies + delay)); 341 spin_unlock_bh(&tun->lock); 342 } 343 344 unlock: 345 rcu_read_unlock(); 346 } 347 348 /** 349 * Save the hash received in the stack receive path and update the 350 * flow_hash table accordingly. 351 */ 352 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 353 { 354 if (unlikely(e->rps_rxhash != hash)) { 355 sock_rps_reset_flow_hash(e->rps_rxhash); 356 e->rps_rxhash = hash; 357 } 358 } 359 360 /* We try to identify a flow through its rxhash first. The reason that 361 * we do not check rxq no. is because some cards(e.g 82599), chooses 362 * the rxq based on the txq where the last packet of the flow comes. As 363 * the userspace application move between processors, we may get a 364 * different rxq no. here. If we could not get rxhash, then we would 365 * hope the rxq no. may help here. 366 */ 367 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb) 368 { 369 struct tun_struct *tun = netdev_priv(dev); 370 struct tun_flow_entry *e; 371 u32 txq = 0; 372 u32 numqueues = 0; 373 374 rcu_read_lock(); 375 numqueues = ACCESS_ONCE(tun->numqueues); 376 377 txq = skb_get_hash(skb); 378 if (txq) { 379 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 380 if (e) { 381 txq = e->queue_index; 382 tun_flow_save_rps_rxhash(e, txq); 383 } else 384 /* use multiply and shift instead of expensive divide */ 385 txq = ((u64)txq * numqueues) >> 32; 386 } else if (likely(skb_rx_queue_recorded(skb))) { 387 txq = skb_get_rx_queue(skb); 388 while (unlikely(txq >= numqueues)) 389 txq -= numqueues; 390 } 391 392 rcu_read_unlock(); 393 return txq; 394 } 395 396 static inline bool tun_not_capable(struct tun_struct *tun) 397 { 398 const struct cred *cred = current_cred(); 399 struct net *net = dev_net(tun->dev); 400 401 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 402 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 403 !ns_capable(net->user_ns, CAP_NET_ADMIN); 404 } 405 406 static void tun_set_real_num_queues(struct tun_struct *tun) 407 { 408 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 409 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 410 } 411 412 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 413 { 414 tfile->detached = tun; 415 list_add_tail(&tfile->next, &tun->disabled); 416 ++tun->numdisabled; 417 } 418 419 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 420 { 421 struct tun_struct *tun = tfile->detached; 422 423 tfile->detached = NULL; 424 list_del_init(&tfile->next); 425 --tun->numdisabled; 426 return tun; 427 } 428 429 static void tun_queue_purge(struct tun_file *tfile) 430 { 431 skb_queue_purge(&tfile->sk.sk_receive_queue); 432 skb_queue_purge(&tfile->sk.sk_error_queue); 433 } 434 435 static void __tun_detach(struct tun_file *tfile, bool clean) 436 { 437 struct tun_file *ntfile; 438 struct tun_struct *tun; 439 440 tun = rtnl_dereference(tfile->tun); 441 442 if (tun && !tfile->detached) { 443 u16 index = tfile->queue_index; 444 BUG_ON(index >= tun->numqueues); 445 446 rcu_assign_pointer(tun->tfiles[index], 447 tun->tfiles[tun->numqueues - 1]); 448 ntfile = rtnl_dereference(tun->tfiles[index]); 449 ntfile->queue_index = index; 450 451 --tun->numqueues; 452 if (clean) { 453 rcu_assign_pointer(tfile->tun, NULL); 454 sock_put(&tfile->sk); 455 } else 456 tun_disable_queue(tun, tfile); 457 458 synchronize_net(); 459 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 460 /* Drop read queue */ 461 tun_queue_purge(tfile); 462 tun_set_real_num_queues(tun); 463 } else if (tfile->detached && clean) { 464 tun = tun_enable_queue(tfile); 465 sock_put(&tfile->sk); 466 } 467 468 if (clean) { 469 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 470 netif_carrier_off(tun->dev); 471 472 if (!(tun->flags & TUN_PERSIST) && 473 tun->dev->reg_state == NETREG_REGISTERED) 474 unregister_netdevice(tun->dev); 475 } 476 477 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 478 &tfile->socket.flags)); 479 sk_release_kernel(&tfile->sk); 480 } 481 } 482 483 static void tun_detach(struct tun_file *tfile, bool clean) 484 { 485 rtnl_lock(); 486 __tun_detach(tfile, clean); 487 rtnl_unlock(); 488 } 489 490 static void tun_detach_all(struct net_device *dev) 491 { 492 struct tun_struct *tun = netdev_priv(dev); 493 struct tun_file *tfile, *tmp; 494 int i, n = tun->numqueues; 495 496 for (i = 0; i < n; i++) { 497 tfile = rtnl_dereference(tun->tfiles[i]); 498 BUG_ON(!tfile); 499 wake_up_all(&tfile->wq.wait); 500 rcu_assign_pointer(tfile->tun, NULL); 501 --tun->numqueues; 502 } 503 list_for_each_entry(tfile, &tun->disabled, next) { 504 wake_up_all(&tfile->wq.wait); 505 rcu_assign_pointer(tfile->tun, NULL); 506 } 507 BUG_ON(tun->numqueues != 0); 508 509 synchronize_net(); 510 for (i = 0; i < n; i++) { 511 tfile = rtnl_dereference(tun->tfiles[i]); 512 /* Drop read queue */ 513 tun_queue_purge(tfile); 514 sock_put(&tfile->sk); 515 } 516 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 517 tun_enable_queue(tfile); 518 tun_queue_purge(tfile); 519 sock_put(&tfile->sk); 520 } 521 BUG_ON(tun->numdisabled != 0); 522 523 if (tun->flags & TUN_PERSIST) 524 module_put(THIS_MODULE); 525 } 526 527 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) 528 { 529 struct tun_file *tfile = file->private_data; 530 int err; 531 532 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 533 if (err < 0) 534 goto out; 535 536 err = -EINVAL; 537 if (rtnl_dereference(tfile->tun) && !tfile->detached) 538 goto out; 539 540 err = -EBUSY; 541 if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1) 542 goto out; 543 544 err = -E2BIG; 545 if (!tfile->detached && 546 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 547 goto out; 548 549 err = 0; 550 551 /* Re-attach the filter to persist device */ 552 if (!skip_filter && (tun->filter_attached == true)) { 553 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 554 if (!err) 555 goto out; 556 } 557 tfile->queue_index = tun->numqueues; 558 rcu_assign_pointer(tfile->tun, tun); 559 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 560 tun->numqueues++; 561 562 if (tfile->detached) 563 tun_enable_queue(tfile); 564 else 565 sock_hold(&tfile->sk); 566 567 tun_set_real_num_queues(tun); 568 569 /* device is allowed to go away first, so no need to hold extra 570 * refcnt. 571 */ 572 573 out: 574 return err; 575 } 576 577 static struct tun_struct *__tun_get(struct tun_file *tfile) 578 { 579 struct tun_struct *tun; 580 581 rcu_read_lock(); 582 tun = rcu_dereference(tfile->tun); 583 if (tun) 584 dev_hold(tun->dev); 585 rcu_read_unlock(); 586 587 return tun; 588 } 589 590 static struct tun_struct *tun_get(struct file *file) 591 { 592 return __tun_get(file->private_data); 593 } 594 595 static void tun_put(struct tun_struct *tun) 596 { 597 dev_put(tun->dev); 598 } 599 600 /* TAP filtering */ 601 static void addr_hash_set(u32 *mask, const u8 *addr) 602 { 603 int n = ether_crc(ETH_ALEN, addr) >> 26; 604 mask[n >> 5] |= (1 << (n & 31)); 605 } 606 607 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 608 { 609 int n = ether_crc(ETH_ALEN, addr) >> 26; 610 return mask[n >> 5] & (1 << (n & 31)); 611 } 612 613 static int update_filter(struct tap_filter *filter, void __user *arg) 614 { 615 struct { u8 u[ETH_ALEN]; } *addr; 616 struct tun_filter uf; 617 int err, alen, n, nexact; 618 619 if (copy_from_user(&uf, arg, sizeof(uf))) 620 return -EFAULT; 621 622 if (!uf.count) { 623 /* Disabled */ 624 filter->count = 0; 625 return 0; 626 } 627 628 alen = ETH_ALEN * uf.count; 629 addr = kmalloc(alen, GFP_KERNEL); 630 if (!addr) 631 return -ENOMEM; 632 633 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 634 err = -EFAULT; 635 goto done; 636 } 637 638 /* The filter is updated without holding any locks. Which is 639 * perfectly safe. We disable it first and in the worst 640 * case we'll accept a few undesired packets. */ 641 filter->count = 0; 642 wmb(); 643 644 /* Use first set of addresses as an exact filter */ 645 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 646 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 647 648 nexact = n; 649 650 /* Remaining multicast addresses are hashed, 651 * unicast will leave the filter disabled. */ 652 memset(filter->mask, 0, sizeof(filter->mask)); 653 for (; n < uf.count; n++) { 654 if (!is_multicast_ether_addr(addr[n].u)) { 655 err = 0; /* no filter */ 656 goto done; 657 } 658 addr_hash_set(filter->mask, addr[n].u); 659 } 660 661 /* For ALLMULTI just set the mask to all ones. 662 * This overrides the mask populated above. */ 663 if ((uf.flags & TUN_FLT_ALLMULTI)) 664 memset(filter->mask, ~0, sizeof(filter->mask)); 665 666 /* Now enable the filter */ 667 wmb(); 668 filter->count = nexact; 669 670 /* Return the number of exact filters */ 671 err = nexact; 672 673 done: 674 kfree(addr); 675 return err; 676 } 677 678 /* Returns: 0 - drop, !=0 - accept */ 679 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 680 { 681 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 682 * at this point. */ 683 struct ethhdr *eh = (struct ethhdr *) skb->data; 684 int i; 685 686 /* Exact match */ 687 for (i = 0; i < filter->count; i++) 688 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 689 return 1; 690 691 /* Inexact match (multicast only) */ 692 if (is_multicast_ether_addr(eh->h_dest)) 693 return addr_hash_test(filter->mask, eh->h_dest); 694 695 return 0; 696 } 697 698 /* 699 * Checks whether the packet is accepted or not. 700 * Returns: 0 - drop, !=0 - accept 701 */ 702 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 703 { 704 if (!filter->count) 705 return 1; 706 707 return run_filter(filter, skb); 708 } 709 710 /* Network device part of the driver */ 711 712 static const struct ethtool_ops tun_ethtool_ops; 713 714 /* Net device detach from fd. */ 715 static void tun_net_uninit(struct net_device *dev) 716 { 717 tun_detach_all(dev); 718 } 719 720 /* Net device open. */ 721 static int tun_net_open(struct net_device *dev) 722 { 723 netif_tx_start_all_queues(dev); 724 return 0; 725 } 726 727 /* Net device close. */ 728 static int tun_net_close(struct net_device *dev) 729 { 730 netif_tx_stop_all_queues(dev); 731 return 0; 732 } 733 734 /* Net device start xmit */ 735 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 736 { 737 struct tun_struct *tun = netdev_priv(dev); 738 int txq = skb->queue_mapping; 739 struct tun_file *tfile; 740 741 rcu_read_lock(); 742 tfile = rcu_dereference(tun->tfiles[txq]); 743 744 /* Drop packet if interface is not attached */ 745 if (txq >= tun->numqueues) 746 goto drop; 747 748 if (tun->numqueues == 1) { 749 /* Select queue was not called for the skbuff, so we extract the 750 * RPS hash and save it into the flow_table here. 751 */ 752 __u32 rxhash; 753 754 rxhash = skb_get_hash(skb); 755 if (rxhash) { 756 struct tun_flow_entry *e; 757 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], 758 rxhash); 759 if (e) 760 tun_flow_save_rps_rxhash(e, rxhash); 761 } 762 } 763 764 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 765 766 BUG_ON(!tfile); 767 768 /* Drop if the filter does not like it. 769 * This is a noop if the filter is disabled. 770 * Filter can be enabled only for the TAP devices. */ 771 if (!check_filter(&tun->txflt, skb)) 772 goto drop; 773 774 if (tfile->socket.sk->sk_filter && 775 sk_filter(tfile->socket.sk, skb)) 776 goto drop; 777 778 /* Limit the number of packets queued by dividing txq length with the 779 * number of queues. 780 */ 781 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) 782 >= dev->tx_queue_len / tun->numqueues) 783 goto drop; 784 785 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 786 goto drop; 787 788 if (skb->sk) { 789 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags); 790 sw_tx_timestamp(skb); 791 } 792 793 /* Orphan the skb - required as we might hang on to it 794 * for indefinite time. 795 */ 796 skb_orphan(skb); 797 798 nf_reset(skb); 799 800 /* Enqueue packet */ 801 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 802 803 /* Notify and wake up reader process */ 804 if (tfile->flags & TUN_FASYNC) 805 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 806 wake_up_interruptible_poll(&tfile->wq.wait, POLLIN | 807 POLLRDNORM | POLLRDBAND); 808 809 rcu_read_unlock(); 810 return NETDEV_TX_OK; 811 812 drop: 813 dev->stats.tx_dropped++; 814 skb_tx_error(skb); 815 kfree_skb(skb); 816 rcu_read_unlock(); 817 return NETDEV_TX_OK; 818 } 819 820 static void tun_net_mclist(struct net_device *dev) 821 { 822 /* 823 * This callback is supposed to deal with mc filter in 824 * _rx_ path and has nothing to do with the _tx_ path. 825 * In rx path we always accept everything userspace gives us. 826 */ 827 } 828 829 #define MIN_MTU 68 830 #define MAX_MTU 65535 831 832 static int 833 tun_net_change_mtu(struct net_device *dev, int new_mtu) 834 { 835 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 836 return -EINVAL; 837 dev->mtu = new_mtu; 838 return 0; 839 } 840 841 static netdev_features_t tun_net_fix_features(struct net_device *dev, 842 netdev_features_t features) 843 { 844 struct tun_struct *tun = netdev_priv(dev); 845 846 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 847 } 848 #ifdef CONFIG_NET_POLL_CONTROLLER 849 static void tun_poll_controller(struct net_device *dev) 850 { 851 /* 852 * Tun only receives frames when: 853 * 1) the char device endpoint gets data from user space 854 * 2) the tun socket gets a sendmsg call from user space 855 * Since both of those are synchronous operations, we are guaranteed 856 * never to have pending data when we poll for it 857 * so there is nothing to do here but return. 858 * We need this though so netpoll recognizes us as an interface that 859 * supports polling, which enables bridge devices in virt setups to 860 * still use netconsole 861 */ 862 return; 863 } 864 #endif 865 static const struct net_device_ops tun_netdev_ops = { 866 .ndo_uninit = tun_net_uninit, 867 .ndo_open = tun_net_open, 868 .ndo_stop = tun_net_close, 869 .ndo_start_xmit = tun_net_xmit, 870 .ndo_change_mtu = tun_net_change_mtu, 871 .ndo_fix_features = tun_net_fix_features, 872 .ndo_select_queue = tun_select_queue, 873 #ifdef CONFIG_NET_POLL_CONTROLLER 874 .ndo_poll_controller = tun_poll_controller, 875 #endif 876 }; 877 878 static const struct net_device_ops tap_netdev_ops = { 879 .ndo_uninit = tun_net_uninit, 880 .ndo_open = tun_net_open, 881 .ndo_stop = tun_net_close, 882 .ndo_start_xmit = tun_net_xmit, 883 .ndo_change_mtu = tun_net_change_mtu, 884 .ndo_fix_features = tun_net_fix_features, 885 .ndo_set_rx_mode = tun_net_mclist, 886 .ndo_set_mac_address = eth_mac_addr, 887 .ndo_validate_addr = eth_validate_addr, 888 .ndo_select_queue = tun_select_queue, 889 #ifdef CONFIG_NET_POLL_CONTROLLER 890 .ndo_poll_controller = tun_poll_controller, 891 #endif 892 }; 893 894 static void tun_flow_init(struct tun_struct *tun) 895 { 896 int i; 897 898 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 899 INIT_HLIST_HEAD(&tun->flows[i]); 900 901 tun->ageing_time = TUN_FLOW_EXPIRE; 902 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 903 mod_timer(&tun->flow_gc_timer, 904 round_jiffies_up(jiffies + tun->ageing_time)); 905 } 906 907 static void tun_flow_uninit(struct tun_struct *tun) 908 { 909 del_timer_sync(&tun->flow_gc_timer); 910 tun_flow_flush(tun); 911 } 912 913 /* Initialize net device. */ 914 static void tun_net_init(struct net_device *dev) 915 { 916 struct tun_struct *tun = netdev_priv(dev); 917 918 switch (tun->flags & TUN_TYPE_MASK) { 919 case TUN_TUN_DEV: 920 dev->netdev_ops = &tun_netdev_ops; 921 922 /* Point-to-Point TUN Device */ 923 dev->hard_header_len = 0; 924 dev->addr_len = 0; 925 dev->mtu = 1500; 926 927 /* Zero header length */ 928 dev->type = ARPHRD_NONE; 929 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 930 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 931 break; 932 933 case TUN_TAP_DEV: 934 dev->netdev_ops = &tap_netdev_ops; 935 /* Ethernet TAP Device */ 936 ether_setup(dev); 937 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 938 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 939 940 eth_hw_addr_random(dev); 941 942 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 943 break; 944 } 945 } 946 947 /* Character device part */ 948 949 /* Poll */ 950 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 951 { 952 struct tun_file *tfile = file->private_data; 953 struct tun_struct *tun = __tun_get(tfile); 954 struct sock *sk; 955 unsigned int mask = 0; 956 957 if (!tun) 958 return POLLERR; 959 960 sk = tfile->socket.sk; 961 962 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 963 964 poll_wait(file, &tfile->wq.wait, wait); 965 966 if (!skb_queue_empty(&sk->sk_receive_queue)) 967 mask |= POLLIN | POLLRDNORM; 968 969 if (sock_writeable(sk) || 970 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 971 sock_writeable(sk))) 972 mask |= POLLOUT | POLLWRNORM; 973 974 if (tun->dev->reg_state != NETREG_REGISTERED) 975 mask = POLLERR; 976 977 tun_put(tun); 978 return mask; 979 } 980 981 /* prepad is the amount to reserve at front. len is length after that. 982 * linear is a hint as to how much to copy (usually headers). */ 983 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 984 size_t prepad, size_t len, 985 size_t linear, int noblock) 986 { 987 struct sock *sk = tfile->socket.sk; 988 struct sk_buff *skb; 989 int err; 990 991 /* Under a page? Don't bother with paged skb. */ 992 if (prepad + len < PAGE_SIZE || !linear) 993 linear = len; 994 995 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 996 &err, 0); 997 if (!skb) 998 return ERR_PTR(err); 999 1000 skb_reserve(skb, prepad); 1001 skb_put(skb, linear); 1002 skb->data_len = len - linear; 1003 skb->len += len - linear; 1004 1005 return skb; 1006 } 1007 1008 /* Get packet from user space buffer */ 1009 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1010 void *msg_control, const struct iovec *iv, 1011 size_t total_len, size_t count, int noblock) 1012 { 1013 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1014 struct sk_buff *skb; 1015 size_t len = total_len, align = NET_SKB_PAD, linear; 1016 struct virtio_net_hdr gso = { 0 }; 1017 int good_linear; 1018 int offset = 0; 1019 int copylen; 1020 bool zerocopy = false; 1021 int err; 1022 u32 rxhash; 1023 1024 if (!(tun->flags & TUN_NO_PI)) { 1025 if (len < sizeof(pi)) 1026 return -EINVAL; 1027 len -= sizeof(pi); 1028 1029 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) 1030 return -EFAULT; 1031 offset += sizeof(pi); 1032 } 1033 1034 if (tun->flags & TUN_VNET_HDR) { 1035 if (len < tun->vnet_hdr_sz) 1036 return -EINVAL; 1037 len -= tun->vnet_hdr_sz; 1038 1039 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) 1040 return -EFAULT; 1041 1042 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1043 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) 1044 gso.hdr_len = gso.csum_start + gso.csum_offset + 2; 1045 1046 if (gso.hdr_len > len) 1047 return -EINVAL; 1048 offset += tun->vnet_hdr_sz; 1049 } 1050 1051 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { 1052 align += NET_IP_ALIGN; 1053 if (unlikely(len < ETH_HLEN || 1054 (gso.hdr_len && gso.hdr_len < ETH_HLEN))) 1055 return -EINVAL; 1056 } 1057 1058 good_linear = SKB_MAX_HEAD(align); 1059 1060 if (msg_control) { 1061 /* There are 256 bytes to be copied in skb, so there is 1062 * enough room for skb expand head in case it is used. 1063 * The rest of the buffer is mapped from userspace. 1064 */ 1065 copylen = gso.hdr_len ? gso.hdr_len : GOODCOPY_LEN; 1066 if (copylen > good_linear) 1067 copylen = good_linear; 1068 linear = copylen; 1069 if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS) 1070 zerocopy = true; 1071 } 1072 1073 if (!zerocopy) { 1074 copylen = len; 1075 if (gso.hdr_len > good_linear) 1076 linear = good_linear; 1077 else 1078 linear = gso.hdr_len; 1079 } 1080 1081 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1082 if (IS_ERR(skb)) { 1083 if (PTR_ERR(skb) != -EAGAIN) 1084 tun->dev->stats.rx_dropped++; 1085 return PTR_ERR(skb); 1086 } 1087 1088 if (zerocopy) 1089 err = zerocopy_sg_from_iovec(skb, iv, offset, count); 1090 else { 1091 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len); 1092 if (!err && msg_control) { 1093 struct ubuf_info *uarg = msg_control; 1094 uarg->callback(uarg, false); 1095 } 1096 } 1097 1098 if (err) { 1099 tun->dev->stats.rx_dropped++; 1100 kfree_skb(skb); 1101 return -EFAULT; 1102 } 1103 1104 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1105 if (!skb_partial_csum_set(skb, gso.csum_start, 1106 gso.csum_offset)) { 1107 tun->dev->stats.rx_frame_errors++; 1108 kfree_skb(skb); 1109 return -EINVAL; 1110 } 1111 } 1112 1113 switch (tun->flags & TUN_TYPE_MASK) { 1114 case TUN_TUN_DEV: 1115 if (tun->flags & TUN_NO_PI) { 1116 switch (skb->data[0] & 0xf0) { 1117 case 0x40: 1118 pi.proto = htons(ETH_P_IP); 1119 break; 1120 case 0x60: 1121 pi.proto = htons(ETH_P_IPV6); 1122 break; 1123 default: 1124 tun->dev->stats.rx_dropped++; 1125 kfree_skb(skb); 1126 return -EINVAL; 1127 } 1128 } 1129 1130 skb_reset_mac_header(skb); 1131 skb->protocol = pi.proto; 1132 skb->dev = tun->dev; 1133 break; 1134 case TUN_TAP_DEV: 1135 skb->protocol = eth_type_trans(skb, tun->dev); 1136 break; 1137 } 1138 1139 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1140 pr_debug("GSO!\n"); 1141 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1142 case VIRTIO_NET_HDR_GSO_TCPV4: 1143 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1144 break; 1145 case VIRTIO_NET_HDR_GSO_TCPV6: 1146 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1147 break; 1148 case VIRTIO_NET_HDR_GSO_UDP: 1149 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1150 break; 1151 default: 1152 tun->dev->stats.rx_frame_errors++; 1153 kfree_skb(skb); 1154 return -EINVAL; 1155 } 1156 1157 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1158 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1159 1160 skb_shinfo(skb)->gso_size = gso.gso_size; 1161 if (skb_shinfo(skb)->gso_size == 0) { 1162 tun->dev->stats.rx_frame_errors++; 1163 kfree_skb(skb); 1164 return -EINVAL; 1165 } 1166 1167 /* Header must be checked, and gso_segs computed. */ 1168 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1169 skb_shinfo(skb)->gso_segs = 0; 1170 } 1171 1172 /* copy skb_ubuf_info for callback when skb has no error */ 1173 if (zerocopy) { 1174 skb_shinfo(skb)->destructor_arg = msg_control; 1175 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1176 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1177 } 1178 1179 skb_reset_network_header(skb); 1180 skb_probe_transport_header(skb, 0); 1181 1182 rxhash = skb_get_hash(skb); 1183 netif_rx_ni(skb); 1184 1185 tun->dev->stats.rx_packets++; 1186 tun->dev->stats.rx_bytes += len; 1187 1188 tun_flow_update(tun, rxhash, tfile); 1189 return total_len; 1190 } 1191 1192 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 1193 unsigned long count, loff_t pos) 1194 { 1195 struct file *file = iocb->ki_filp; 1196 struct tun_struct *tun = tun_get(file); 1197 struct tun_file *tfile = file->private_data; 1198 ssize_t result; 1199 1200 if (!tun) 1201 return -EBADFD; 1202 1203 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count); 1204 1205 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count), 1206 count, file->f_flags & O_NONBLOCK); 1207 1208 tun_put(tun); 1209 return result; 1210 } 1211 1212 /* Put packet to the user space buffer */ 1213 static ssize_t tun_put_user(struct tun_struct *tun, 1214 struct tun_file *tfile, 1215 struct sk_buff *skb, 1216 const struct iovec *iv, int len) 1217 { 1218 struct tun_pi pi = { 0, skb->protocol }; 1219 ssize_t total = 0; 1220 int vlan_offset = 0, copied; 1221 1222 if (!(tun->flags & TUN_NO_PI)) { 1223 if ((len -= sizeof(pi)) < 0) 1224 return -EINVAL; 1225 1226 if (len < skb->len) { 1227 /* Packet will be striped */ 1228 pi.flags |= TUN_PKT_STRIP; 1229 } 1230 1231 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi))) 1232 return -EFAULT; 1233 total += sizeof(pi); 1234 } 1235 1236 if (tun->flags & TUN_VNET_HDR) { 1237 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1238 if ((len -= tun->vnet_hdr_sz) < 0) 1239 return -EINVAL; 1240 1241 if (skb_is_gso(skb)) { 1242 struct skb_shared_info *sinfo = skb_shinfo(skb); 1243 1244 /* This is a hint as to how much should be linear. */ 1245 gso.hdr_len = skb_headlen(skb); 1246 gso.gso_size = sinfo->gso_size; 1247 if (sinfo->gso_type & SKB_GSO_TCPV4) 1248 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1249 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1250 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1251 else if (sinfo->gso_type & SKB_GSO_UDP) 1252 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1253 else { 1254 pr_err("unexpected GSO type: " 1255 "0x%x, gso_size %d, hdr_len %d\n", 1256 sinfo->gso_type, gso.gso_size, 1257 gso.hdr_len); 1258 print_hex_dump(KERN_ERR, "tun: ", 1259 DUMP_PREFIX_NONE, 1260 16, 1, skb->head, 1261 min((int)gso.hdr_len, 64), true); 1262 WARN_ON_ONCE(1); 1263 return -EINVAL; 1264 } 1265 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1266 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1267 } else 1268 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1269 1270 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1271 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1272 gso.csum_start = skb_checksum_start_offset(skb); 1273 gso.csum_offset = skb->csum_offset; 1274 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1275 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1276 } /* else everything is zero */ 1277 1278 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, 1279 sizeof(gso)))) 1280 return -EFAULT; 1281 total += tun->vnet_hdr_sz; 1282 } 1283 1284 copied = total; 1285 total += skb->len; 1286 if (!vlan_tx_tag_present(skb)) { 1287 len = min_t(int, skb->len, len); 1288 } else { 1289 int copy, ret; 1290 struct { 1291 __be16 h_vlan_proto; 1292 __be16 h_vlan_TCI; 1293 } veth; 1294 1295 veth.h_vlan_proto = skb->vlan_proto; 1296 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 1297 1298 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1299 len = min_t(int, skb->len + VLAN_HLEN, len); 1300 total += VLAN_HLEN; 1301 1302 copy = min_t(int, vlan_offset, len); 1303 ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); 1304 len -= copy; 1305 copied += copy; 1306 if (ret || !len) 1307 goto done; 1308 1309 copy = min_t(int, sizeof(veth), len); 1310 ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy); 1311 len -= copy; 1312 copied += copy; 1313 if (ret || !len) 1314 goto done; 1315 } 1316 1317 skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len); 1318 1319 done: 1320 tun->dev->stats.tx_packets++; 1321 tun->dev->stats.tx_bytes += len; 1322 1323 return total; 1324 } 1325 1326 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1327 const struct iovec *iv, ssize_t len, int noblock) 1328 { 1329 DECLARE_WAITQUEUE(wait, current); 1330 struct sk_buff *skb; 1331 ssize_t ret = 0; 1332 1333 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1334 1335 if (unlikely(!noblock)) 1336 add_wait_queue(&tfile->wq.wait, &wait); 1337 while (len) { 1338 if (unlikely(!noblock)) 1339 current->state = TASK_INTERRUPTIBLE; 1340 1341 /* Read frames from the queue */ 1342 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) { 1343 if (noblock) { 1344 ret = -EAGAIN; 1345 break; 1346 } 1347 if (signal_pending(current)) { 1348 ret = -ERESTARTSYS; 1349 break; 1350 } 1351 if (tun->dev->reg_state != NETREG_REGISTERED) { 1352 ret = -EIO; 1353 break; 1354 } 1355 1356 /* Nothing to read, let's sleep */ 1357 schedule(); 1358 continue; 1359 } 1360 1361 ret = tun_put_user(tun, tfile, skb, iv, len); 1362 kfree_skb(skb); 1363 break; 1364 } 1365 1366 if (unlikely(!noblock)) { 1367 current->state = TASK_RUNNING; 1368 remove_wait_queue(&tfile->wq.wait, &wait); 1369 } 1370 1371 return ret; 1372 } 1373 1374 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 1375 unsigned long count, loff_t pos) 1376 { 1377 struct file *file = iocb->ki_filp; 1378 struct tun_file *tfile = file->private_data; 1379 struct tun_struct *tun = __tun_get(tfile); 1380 ssize_t len, ret; 1381 1382 if (!tun) 1383 return -EBADFD; 1384 len = iov_length(iv, count); 1385 if (len < 0) { 1386 ret = -EINVAL; 1387 goto out; 1388 } 1389 1390 ret = tun_do_read(tun, tfile, iv, len, 1391 file->f_flags & O_NONBLOCK); 1392 ret = min_t(ssize_t, ret, len); 1393 if (ret > 0) 1394 iocb->ki_pos = ret; 1395 out: 1396 tun_put(tun); 1397 return ret; 1398 } 1399 1400 static void tun_free_netdev(struct net_device *dev) 1401 { 1402 struct tun_struct *tun = netdev_priv(dev); 1403 1404 BUG_ON(!(list_empty(&tun->disabled))); 1405 tun_flow_uninit(tun); 1406 security_tun_dev_free_security(tun->security); 1407 free_netdev(dev); 1408 } 1409 1410 static void tun_setup(struct net_device *dev) 1411 { 1412 struct tun_struct *tun = netdev_priv(dev); 1413 1414 tun->owner = INVALID_UID; 1415 tun->group = INVALID_GID; 1416 1417 dev->ethtool_ops = &tun_ethtool_ops; 1418 dev->destructor = tun_free_netdev; 1419 } 1420 1421 /* Trivial set of netlink ops to allow deleting tun or tap 1422 * device with netlink. 1423 */ 1424 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1425 { 1426 return -EINVAL; 1427 } 1428 1429 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1430 .kind = DRV_NAME, 1431 .priv_size = sizeof(struct tun_struct), 1432 .setup = tun_setup, 1433 .validate = tun_validate, 1434 }; 1435 1436 static void tun_sock_write_space(struct sock *sk) 1437 { 1438 struct tun_file *tfile; 1439 wait_queue_head_t *wqueue; 1440 1441 if (!sock_writeable(sk)) 1442 return; 1443 1444 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1445 return; 1446 1447 wqueue = sk_sleep(sk); 1448 if (wqueue && waitqueue_active(wqueue)) 1449 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1450 POLLWRNORM | POLLWRBAND); 1451 1452 tfile = container_of(sk, struct tun_file, sk); 1453 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1454 } 1455 1456 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1457 struct msghdr *m, size_t total_len) 1458 { 1459 int ret; 1460 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1461 struct tun_struct *tun = __tun_get(tfile); 1462 1463 if (!tun) 1464 return -EBADFD; 1465 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len, 1466 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); 1467 tun_put(tun); 1468 return ret; 1469 } 1470 1471 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1472 struct msghdr *m, size_t total_len, 1473 int flags) 1474 { 1475 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1476 struct tun_struct *tun = __tun_get(tfile); 1477 int ret; 1478 1479 if (!tun) 1480 return -EBADFD; 1481 1482 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1483 ret = -EINVAL; 1484 goto out; 1485 } 1486 if (flags & MSG_ERRQUEUE) { 1487 ret = sock_recv_errqueue(sock->sk, m, total_len, 1488 SOL_PACKET, TUN_TX_TIMESTAMP); 1489 goto out; 1490 } 1491 ret = tun_do_read(tun, tfile, m->msg_iov, total_len, 1492 flags & MSG_DONTWAIT); 1493 if (ret > total_len) { 1494 m->msg_flags |= MSG_TRUNC; 1495 ret = flags & MSG_TRUNC ? ret : total_len; 1496 } 1497 out: 1498 tun_put(tun); 1499 return ret; 1500 } 1501 1502 static int tun_release(struct socket *sock) 1503 { 1504 if (sock->sk) 1505 sock_put(sock->sk); 1506 return 0; 1507 } 1508 1509 /* Ops structure to mimic raw sockets with tun */ 1510 static const struct proto_ops tun_socket_ops = { 1511 .sendmsg = tun_sendmsg, 1512 .recvmsg = tun_recvmsg, 1513 .release = tun_release, 1514 }; 1515 1516 static struct proto tun_proto = { 1517 .name = "tun", 1518 .owner = THIS_MODULE, 1519 .obj_size = sizeof(struct tun_file), 1520 }; 1521 1522 static int tun_flags(struct tun_struct *tun) 1523 { 1524 int flags = 0; 1525 1526 if (tun->flags & TUN_TUN_DEV) 1527 flags |= IFF_TUN; 1528 else 1529 flags |= IFF_TAP; 1530 1531 if (tun->flags & TUN_NO_PI) 1532 flags |= IFF_NO_PI; 1533 1534 /* This flag has no real effect. We track the value for backwards 1535 * compatibility. 1536 */ 1537 if (tun->flags & TUN_ONE_QUEUE) 1538 flags |= IFF_ONE_QUEUE; 1539 1540 if (tun->flags & TUN_VNET_HDR) 1541 flags |= IFF_VNET_HDR; 1542 1543 if (tun->flags & TUN_TAP_MQ) 1544 flags |= IFF_MULTI_QUEUE; 1545 1546 if (tun->flags & TUN_PERSIST) 1547 flags |= IFF_PERSIST; 1548 1549 return flags; 1550 } 1551 1552 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1553 char *buf) 1554 { 1555 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1556 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1557 } 1558 1559 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1560 char *buf) 1561 { 1562 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1563 return uid_valid(tun->owner)? 1564 sprintf(buf, "%u\n", 1565 from_kuid_munged(current_user_ns(), tun->owner)): 1566 sprintf(buf, "-1\n"); 1567 } 1568 1569 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1570 char *buf) 1571 { 1572 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1573 return gid_valid(tun->group) ? 1574 sprintf(buf, "%u\n", 1575 from_kgid_munged(current_user_ns(), tun->group)): 1576 sprintf(buf, "-1\n"); 1577 } 1578 1579 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1580 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1581 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1582 1583 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1584 { 1585 struct tun_struct *tun; 1586 struct tun_file *tfile = file->private_data; 1587 struct net_device *dev; 1588 int err; 1589 1590 if (tfile->detached) 1591 return -EINVAL; 1592 1593 dev = __dev_get_by_name(net, ifr->ifr_name); 1594 if (dev) { 1595 if (ifr->ifr_flags & IFF_TUN_EXCL) 1596 return -EBUSY; 1597 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1598 tun = netdev_priv(dev); 1599 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1600 tun = netdev_priv(dev); 1601 else 1602 return -EINVAL; 1603 1604 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1605 !!(tun->flags & TUN_TAP_MQ)) 1606 return -EINVAL; 1607 1608 if (tun_not_capable(tun)) 1609 return -EPERM; 1610 err = security_tun_dev_open(tun->security); 1611 if (err < 0) 1612 return err; 1613 1614 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1615 if (err < 0) 1616 return err; 1617 1618 if (tun->flags & TUN_TAP_MQ && 1619 (tun->numqueues + tun->numdisabled > 1)) { 1620 /* One or more queue has already been attached, no need 1621 * to initialize the device again. 1622 */ 1623 return 0; 1624 } 1625 } 1626 else { 1627 char *name; 1628 unsigned long flags = 0; 1629 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1630 MAX_TAP_QUEUES : 1; 1631 1632 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1633 return -EPERM; 1634 err = security_tun_dev_create(); 1635 if (err < 0) 1636 return err; 1637 1638 /* Set dev type */ 1639 if (ifr->ifr_flags & IFF_TUN) { 1640 /* TUN device */ 1641 flags |= TUN_TUN_DEV; 1642 name = "tun%d"; 1643 } else if (ifr->ifr_flags & IFF_TAP) { 1644 /* TAP device */ 1645 flags |= TUN_TAP_DEV; 1646 name = "tap%d"; 1647 } else 1648 return -EINVAL; 1649 1650 if (*ifr->ifr_name) 1651 name = ifr->ifr_name; 1652 1653 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1654 tun_setup, queues, queues); 1655 1656 if (!dev) 1657 return -ENOMEM; 1658 1659 dev_net_set(dev, net); 1660 dev->rtnl_link_ops = &tun_link_ops; 1661 dev->ifindex = tfile->ifindex; 1662 1663 tun = netdev_priv(dev); 1664 tun->dev = dev; 1665 tun->flags = flags; 1666 tun->txflt.count = 0; 1667 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1668 1669 tun->filter_attached = false; 1670 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1671 1672 spin_lock_init(&tun->lock); 1673 1674 err = security_tun_dev_alloc_security(&tun->security); 1675 if (err < 0) 1676 goto err_free_dev; 1677 1678 tun_net_init(dev); 1679 tun_flow_init(tun); 1680 1681 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1682 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1683 NETIF_F_HW_VLAN_STAG_TX; 1684 dev->features = dev->hw_features; 1685 dev->vlan_features = dev->features; 1686 1687 INIT_LIST_HEAD(&tun->disabled); 1688 err = tun_attach(tun, file, false); 1689 if (err < 0) 1690 goto err_free_flow; 1691 1692 err = register_netdevice(tun->dev); 1693 if (err < 0) 1694 goto err_detach; 1695 1696 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1697 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1698 device_create_file(&tun->dev->dev, &dev_attr_group)) 1699 pr_err("Failed to create tun sysfs files\n"); 1700 } 1701 1702 netif_carrier_on(tun->dev); 1703 1704 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1705 1706 if (ifr->ifr_flags & IFF_NO_PI) 1707 tun->flags |= TUN_NO_PI; 1708 else 1709 tun->flags &= ~TUN_NO_PI; 1710 1711 /* This flag has no real effect. We track the value for backwards 1712 * compatibility. 1713 */ 1714 if (ifr->ifr_flags & IFF_ONE_QUEUE) 1715 tun->flags |= TUN_ONE_QUEUE; 1716 else 1717 tun->flags &= ~TUN_ONE_QUEUE; 1718 1719 if (ifr->ifr_flags & IFF_VNET_HDR) 1720 tun->flags |= TUN_VNET_HDR; 1721 else 1722 tun->flags &= ~TUN_VNET_HDR; 1723 1724 if (ifr->ifr_flags & IFF_MULTI_QUEUE) 1725 tun->flags |= TUN_TAP_MQ; 1726 else 1727 tun->flags &= ~TUN_TAP_MQ; 1728 1729 /* Make sure persistent devices do not get stuck in 1730 * xoff state. 1731 */ 1732 if (netif_running(tun->dev)) 1733 netif_tx_wake_all_queues(tun->dev); 1734 1735 strcpy(ifr->ifr_name, tun->dev->name); 1736 return 0; 1737 1738 err_detach: 1739 tun_detach_all(dev); 1740 err_free_flow: 1741 tun_flow_uninit(tun); 1742 security_tun_dev_free_security(tun->security); 1743 err_free_dev: 1744 free_netdev(dev); 1745 return err; 1746 } 1747 1748 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1749 struct ifreq *ifr) 1750 { 1751 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1752 1753 strcpy(ifr->ifr_name, tun->dev->name); 1754 1755 ifr->ifr_flags = tun_flags(tun); 1756 1757 } 1758 1759 /* This is like a cut-down ethtool ops, except done via tun fd so no 1760 * privs required. */ 1761 static int set_offload(struct tun_struct *tun, unsigned long arg) 1762 { 1763 netdev_features_t features = 0; 1764 1765 if (arg & TUN_F_CSUM) { 1766 features |= NETIF_F_HW_CSUM; 1767 arg &= ~TUN_F_CSUM; 1768 1769 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1770 if (arg & TUN_F_TSO_ECN) { 1771 features |= NETIF_F_TSO_ECN; 1772 arg &= ~TUN_F_TSO_ECN; 1773 } 1774 if (arg & TUN_F_TSO4) 1775 features |= NETIF_F_TSO; 1776 if (arg & TUN_F_TSO6) 1777 features |= NETIF_F_TSO6; 1778 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1779 } 1780 1781 if (arg & TUN_F_UFO) { 1782 features |= NETIF_F_UFO; 1783 arg &= ~TUN_F_UFO; 1784 } 1785 } 1786 1787 /* This gives the user a way to test for new features in future by 1788 * trying to set them. */ 1789 if (arg) 1790 return -EINVAL; 1791 1792 tun->set_features = features; 1793 netdev_update_features(tun->dev); 1794 1795 return 0; 1796 } 1797 1798 static void tun_detach_filter(struct tun_struct *tun, int n) 1799 { 1800 int i; 1801 struct tun_file *tfile; 1802 1803 for (i = 0; i < n; i++) { 1804 tfile = rtnl_dereference(tun->tfiles[i]); 1805 sk_detach_filter(tfile->socket.sk); 1806 } 1807 1808 tun->filter_attached = false; 1809 } 1810 1811 static int tun_attach_filter(struct tun_struct *tun) 1812 { 1813 int i, ret = 0; 1814 struct tun_file *tfile; 1815 1816 for (i = 0; i < tun->numqueues; i++) { 1817 tfile = rtnl_dereference(tun->tfiles[i]); 1818 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1819 if (ret) { 1820 tun_detach_filter(tun, i); 1821 return ret; 1822 } 1823 } 1824 1825 tun->filter_attached = true; 1826 return ret; 1827 } 1828 1829 static void tun_set_sndbuf(struct tun_struct *tun) 1830 { 1831 struct tun_file *tfile; 1832 int i; 1833 1834 for (i = 0; i < tun->numqueues; i++) { 1835 tfile = rtnl_dereference(tun->tfiles[i]); 1836 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1837 } 1838 } 1839 1840 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1841 { 1842 struct tun_file *tfile = file->private_data; 1843 struct tun_struct *tun; 1844 int ret = 0; 1845 1846 rtnl_lock(); 1847 1848 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1849 tun = tfile->detached; 1850 if (!tun) { 1851 ret = -EINVAL; 1852 goto unlock; 1853 } 1854 ret = security_tun_dev_attach_queue(tun->security); 1855 if (ret < 0) 1856 goto unlock; 1857 ret = tun_attach(tun, file, false); 1858 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1859 tun = rtnl_dereference(tfile->tun); 1860 if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) 1861 ret = -EINVAL; 1862 else 1863 __tun_detach(tfile, false); 1864 } else 1865 ret = -EINVAL; 1866 1867 unlock: 1868 rtnl_unlock(); 1869 return ret; 1870 } 1871 1872 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1873 unsigned long arg, int ifreq_len) 1874 { 1875 struct tun_file *tfile = file->private_data; 1876 struct tun_struct *tun; 1877 void __user* argp = (void __user*)arg; 1878 struct ifreq ifr; 1879 kuid_t owner; 1880 kgid_t group; 1881 int sndbuf; 1882 int vnet_hdr_sz; 1883 unsigned int ifindex; 1884 int ret; 1885 1886 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1887 if (copy_from_user(&ifr, argp, ifreq_len)) 1888 return -EFAULT; 1889 } else { 1890 memset(&ifr, 0, sizeof(ifr)); 1891 } 1892 if (cmd == TUNGETFEATURES) { 1893 /* Currently this just means: "what IFF flags are valid?". 1894 * This is needed because we never checked for invalid flags on 1895 * TUNSETIFF. */ 1896 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | 1897 IFF_VNET_HDR | IFF_MULTI_QUEUE, 1898 (unsigned int __user*)argp); 1899 } else if (cmd == TUNSETQUEUE) 1900 return tun_set_queue(file, &ifr); 1901 1902 ret = 0; 1903 rtnl_lock(); 1904 1905 tun = __tun_get(tfile); 1906 if (cmd == TUNSETIFF && !tun) { 1907 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1908 1909 ret = tun_set_iff(tfile->net, file, &ifr); 1910 1911 if (ret) 1912 goto unlock; 1913 1914 if (copy_to_user(argp, &ifr, ifreq_len)) 1915 ret = -EFAULT; 1916 goto unlock; 1917 } 1918 if (cmd == TUNSETIFINDEX) { 1919 ret = -EPERM; 1920 if (tun) 1921 goto unlock; 1922 1923 ret = -EFAULT; 1924 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1925 goto unlock; 1926 1927 ret = 0; 1928 tfile->ifindex = ifindex; 1929 goto unlock; 1930 } 1931 1932 ret = -EBADFD; 1933 if (!tun) 1934 goto unlock; 1935 1936 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1937 1938 ret = 0; 1939 switch (cmd) { 1940 case TUNGETIFF: 1941 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1942 1943 if (tfile->detached) 1944 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1945 if (!tfile->socket.sk->sk_filter) 1946 ifr.ifr_flags |= IFF_NOFILTER; 1947 1948 if (copy_to_user(argp, &ifr, ifreq_len)) 1949 ret = -EFAULT; 1950 break; 1951 1952 case TUNSETNOCSUM: 1953 /* Disable/Enable checksum */ 1954 1955 /* [unimplemented] */ 1956 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1957 arg ? "disabled" : "enabled"); 1958 break; 1959 1960 case TUNSETPERSIST: 1961 /* Disable/Enable persist mode. Keep an extra reference to the 1962 * module to prevent the module being unprobed. 1963 */ 1964 if (arg && !(tun->flags & TUN_PERSIST)) { 1965 tun->flags |= TUN_PERSIST; 1966 __module_get(THIS_MODULE); 1967 } 1968 if (!arg && (tun->flags & TUN_PERSIST)) { 1969 tun->flags &= ~TUN_PERSIST; 1970 module_put(THIS_MODULE); 1971 } 1972 1973 tun_debug(KERN_INFO, tun, "persist %s\n", 1974 arg ? "enabled" : "disabled"); 1975 break; 1976 1977 case TUNSETOWNER: 1978 /* Set owner of the device */ 1979 owner = make_kuid(current_user_ns(), arg); 1980 if (!uid_valid(owner)) { 1981 ret = -EINVAL; 1982 break; 1983 } 1984 tun->owner = owner; 1985 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1986 from_kuid(&init_user_ns, tun->owner)); 1987 break; 1988 1989 case TUNSETGROUP: 1990 /* Set group of the device */ 1991 group = make_kgid(current_user_ns(), arg); 1992 if (!gid_valid(group)) { 1993 ret = -EINVAL; 1994 break; 1995 } 1996 tun->group = group; 1997 tun_debug(KERN_INFO, tun, "group set to %u\n", 1998 from_kgid(&init_user_ns, tun->group)); 1999 break; 2000 2001 case TUNSETLINK: 2002 /* Only allow setting the type when the interface is down */ 2003 if (tun->dev->flags & IFF_UP) { 2004 tun_debug(KERN_INFO, tun, 2005 "Linktype set failed because interface is up\n"); 2006 ret = -EBUSY; 2007 } else { 2008 tun->dev->type = (int) arg; 2009 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 2010 tun->dev->type); 2011 ret = 0; 2012 } 2013 break; 2014 2015 #ifdef TUN_DEBUG 2016 case TUNSETDEBUG: 2017 tun->debug = arg; 2018 break; 2019 #endif 2020 case TUNSETOFFLOAD: 2021 ret = set_offload(tun, arg); 2022 break; 2023 2024 case TUNSETTXFILTER: 2025 /* Can be set only for TAPs */ 2026 ret = -EINVAL; 2027 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2028 break; 2029 ret = update_filter(&tun->txflt, (void __user *)arg); 2030 break; 2031 2032 case SIOCGIFHWADDR: 2033 /* Get hw address */ 2034 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 2035 ifr.ifr_hwaddr.sa_family = tun->dev->type; 2036 if (copy_to_user(argp, &ifr, ifreq_len)) 2037 ret = -EFAULT; 2038 break; 2039 2040 case SIOCSIFHWADDR: 2041 /* Set hw address */ 2042 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 2043 ifr.ifr_hwaddr.sa_data); 2044 2045 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2046 break; 2047 2048 case TUNGETSNDBUF: 2049 sndbuf = tfile->socket.sk->sk_sndbuf; 2050 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2051 ret = -EFAULT; 2052 break; 2053 2054 case TUNSETSNDBUF: 2055 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2056 ret = -EFAULT; 2057 break; 2058 } 2059 2060 tun->sndbuf = sndbuf; 2061 tun_set_sndbuf(tun); 2062 break; 2063 2064 case TUNGETVNETHDRSZ: 2065 vnet_hdr_sz = tun->vnet_hdr_sz; 2066 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2067 ret = -EFAULT; 2068 break; 2069 2070 case TUNSETVNETHDRSZ: 2071 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2072 ret = -EFAULT; 2073 break; 2074 } 2075 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2076 ret = -EINVAL; 2077 break; 2078 } 2079 2080 tun->vnet_hdr_sz = vnet_hdr_sz; 2081 break; 2082 2083 case TUNATTACHFILTER: 2084 /* Can be set only for TAPs */ 2085 ret = -EINVAL; 2086 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2087 break; 2088 ret = -EFAULT; 2089 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2090 break; 2091 2092 ret = tun_attach_filter(tun); 2093 break; 2094 2095 case TUNDETACHFILTER: 2096 /* Can be set only for TAPs */ 2097 ret = -EINVAL; 2098 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2099 break; 2100 ret = 0; 2101 tun_detach_filter(tun, tun->numqueues); 2102 break; 2103 2104 case TUNGETFILTER: 2105 ret = -EINVAL; 2106 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2107 break; 2108 ret = -EFAULT; 2109 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2110 break; 2111 ret = 0; 2112 break; 2113 2114 default: 2115 ret = -EINVAL; 2116 break; 2117 } 2118 2119 unlock: 2120 rtnl_unlock(); 2121 if (tun) 2122 tun_put(tun); 2123 return ret; 2124 } 2125 2126 static long tun_chr_ioctl(struct file *file, 2127 unsigned int cmd, unsigned long arg) 2128 { 2129 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2130 } 2131 2132 #ifdef CONFIG_COMPAT 2133 static long tun_chr_compat_ioctl(struct file *file, 2134 unsigned int cmd, unsigned long arg) 2135 { 2136 switch (cmd) { 2137 case TUNSETIFF: 2138 case TUNGETIFF: 2139 case TUNSETTXFILTER: 2140 case TUNGETSNDBUF: 2141 case TUNSETSNDBUF: 2142 case SIOCGIFHWADDR: 2143 case SIOCSIFHWADDR: 2144 arg = (unsigned long)compat_ptr(arg); 2145 break; 2146 default: 2147 arg = (compat_ulong_t)arg; 2148 break; 2149 } 2150 2151 /* 2152 * compat_ifreq is shorter than ifreq, so we must not access beyond 2153 * the end of that structure. All fields that are used in this 2154 * driver are compatible though, we don't need to convert the 2155 * contents. 2156 */ 2157 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2158 } 2159 #endif /* CONFIG_COMPAT */ 2160 2161 static int tun_chr_fasync(int fd, struct file *file, int on) 2162 { 2163 struct tun_file *tfile = file->private_data; 2164 int ret; 2165 2166 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2167 goto out; 2168 2169 if (on) { 2170 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2171 if (ret) 2172 goto out; 2173 tfile->flags |= TUN_FASYNC; 2174 } else 2175 tfile->flags &= ~TUN_FASYNC; 2176 ret = 0; 2177 out: 2178 return ret; 2179 } 2180 2181 static int tun_chr_open(struct inode *inode, struct file * file) 2182 { 2183 struct tun_file *tfile; 2184 2185 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2186 2187 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2188 &tun_proto); 2189 if (!tfile) 2190 return -ENOMEM; 2191 rcu_assign_pointer(tfile->tun, NULL); 2192 tfile->net = get_net(current->nsproxy->net_ns); 2193 tfile->flags = 0; 2194 tfile->ifindex = 0; 2195 2196 rcu_assign_pointer(tfile->socket.wq, &tfile->wq); 2197 init_waitqueue_head(&tfile->wq.wait); 2198 2199 tfile->socket.file = file; 2200 tfile->socket.ops = &tun_socket_ops; 2201 2202 sock_init_data(&tfile->socket, &tfile->sk); 2203 sk_change_net(&tfile->sk, tfile->net); 2204 2205 tfile->sk.sk_write_space = tun_sock_write_space; 2206 tfile->sk.sk_sndbuf = INT_MAX; 2207 2208 file->private_data = tfile; 2209 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2210 INIT_LIST_HEAD(&tfile->next); 2211 2212 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2213 2214 return 0; 2215 } 2216 2217 static int tun_chr_close(struct inode *inode, struct file *file) 2218 { 2219 struct tun_file *tfile = file->private_data; 2220 struct net *net = tfile->net; 2221 2222 tun_detach(tfile, true); 2223 put_net(net); 2224 2225 return 0; 2226 } 2227 2228 static const struct file_operations tun_fops = { 2229 .owner = THIS_MODULE, 2230 .llseek = no_llseek, 2231 .read = do_sync_read, 2232 .aio_read = tun_chr_aio_read, 2233 .write = do_sync_write, 2234 .aio_write = tun_chr_aio_write, 2235 .poll = tun_chr_poll, 2236 .unlocked_ioctl = tun_chr_ioctl, 2237 #ifdef CONFIG_COMPAT 2238 .compat_ioctl = tun_chr_compat_ioctl, 2239 #endif 2240 .open = tun_chr_open, 2241 .release = tun_chr_close, 2242 .fasync = tun_chr_fasync 2243 }; 2244 2245 static struct miscdevice tun_miscdev = { 2246 .minor = TUN_MINOR, 2247 .name = "tun", 2248 .nodename = "net/tun", 2249 .fops = &tun_fops, 2250 }; 2251 2252 /* ethtool interface */ 2253 2254 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2255 { 2256 cmd->supported = 0; 2257 cmd->advertising = 0; 2258 ethtool_cmd_speed_set(cmd, SPEED_10); 2259 cmd->duplex = DUPLEX_FULL; 2260 cmd->port = PORT_TP; 2261 cmd->phy_address = 0; 2262 cmd->transceiver = XCVR_INTERNAL; 2263 cmd->autoneg = AUTONEG_DISABLE; 2264 cmd->maxtxpkt = 0; 2265 cmd->maxrxpkt = 0; 2266 return 0; 2267 } 2268 2269 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2270 { 2271 struct tun_struct *tun = netdev_priv(dev); 2272 2273 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2274 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2275 2276 switch (tun->flags & TUN_TYPE_MASK) { 2277 case TUN_TUN_DEV: 2278 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2279 break; 2280 case TUN_TAP_DEV: 2281 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2282 break; 2283 } 2284 } 2285 2286 static u32 tun_get_msglevel(struct net_device *dev) 2287 { 2288 #ifdef TUN_DEBUG 2289 struct tun_struct *tun = netdev_priv(dev); 2290 return tun->debug; 2291 #else 2292 return -EOPNOTSUPP; 2293 #endif 2294 } 2295 2296 static void tun_set_msglevel(struct net_device *dev, u32 value) 2297 { 2298 #ifdef TUN_DEBUG 2299 struct tun_struct *tun = netdev_priv(dev); 2300 tun->debug = value; 2301 #endif 2302 } 2303 2304 static const struct ethtool_ops tun_ethtool_ops = { 2305 .get_settings = tun_get_settings, 2306 .get_drvinfo = tun_get_drvinfo, 2307 .get_msglevel = tun_get_msglevel, 2308 .set_msglevel = tun_set_msglevel, 2309 .get_link = ethtool_op_get_link, 2310 .get_ts_info = ethtool_op_get_ts_info, 2311 }; 2312 2313 2314 static int __init tun_init(void) 2315 { 2316 int ret = 0; 2317 2318 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2319 pr_info("%s\n", DRV_COPYRIGHT); 2320 2321 ret = rtnl_link_register(&tun_link_ops); 2322 if (ret) { 2323 pr_err("Can't register link_ops\n"); 2324 goto err_linkops; 2325 } 2326 2327 ret = misc_register(&tun_miscdev); 2328 if (ret) { 2329 pr_err("Can't register misc device %d\n", TUN_MINOR); 2330 goto err_misc; 2331 } 2332 return 0; 2333 err_misc: 2334 rtnl_link_unregister(&tun_link_ops); 2335 err_linkops: 2336 return ret; 2337 } 2338 2339 static void tun_cleanup(void) 2340 { 2341 misc_deregister(&tun_miscdev); 2342 rtnl_link_unregister(&tun_link_ops); 2343 } 2344 2345 /* Get an underlying socket object from tun file. Returns error unless file is 2346 * attached to a device. The returned object works like a packet socket, it 2347 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2348 * holding a reference to the file for as long as the socket is in use. */ 2349 struct socket *tun_get_socket(struct file *file) 2350 { 2351 struct tun_file *tfile; 2352 if (file->f_op != &tun_fops) 2353 return ERR_PTR(-EINVAL); 2354 tfile = file->private_data; 2355 if (!tfile) 2356 return ERR_PTR(-EBADFD); 2357 return &tfile->socket; 2358 } 2359 EXPORT_SYMBOL_GPL(tun_get_socket); 2360 2361 module_init(tun_init); 2362 module_exit(tun_cleanup); 2363 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2364 MODULE_AUTHOR(DRV_COPYRIGHT); 2365 MODULE_LICENSE("GPL"); 2366 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2367 MODULE_ALIAS("devname:net/tun"); 2368