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 #include <linux/seq_file.h> 73 74 #include <asm/uaccess.h> 75 76 /* Uncomment to enable debugging */ 77 /* #define TUN_DEBUG 1 */ 78 79 #ifdef TUN_DEBUG 80 static int debug; 81 82 #define tun_debug(level, tun, fmt, args...) \ 83 do { \ 84 if (tun->debug) \ 85 netdev_printk(level, tun->dev, fmt, ##args); \ 86 } while (0) 87 #define DBG1(level, fmt, args...) \ 88 do { \ 89 if (debug == 2) \ 90 printk(level fmt, ##args); \ 91 } while (0) 92 #else 93 #define tun_debug(level, tun, fmt, args...) \ 94 do { \ 95 if (0) \ 96 netdev_printk(level, tun->dev, fmt, ##args); \ 97 } while (0) 98 #define DBG1(level, fmt, args...) \ 99 do { \ 100 if (0) \ 101 printk(level fmt, ##args); \ 102 } while (0) 103 #endif 104 105 #define GOODCOPY_LEN 128 106 107 #define FLT_EXACT_COUNT 8 108 struct tap_filter { 109 unsigned int count; /* Number of addrs. Zero means disabled */ 110 u32 mask[2]; /* Mask of the hashed addrs */ 111 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 112 }; 113 114 /* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for 115 * the netdevice to be fit in one page. So we can make sure the success of 116 * memory allocation. TODO: increase the limit. */ 117 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES 118 #define MAX_TAP_FLOWS 4096 119 120 #define TUN_FLOW_EXPIRE (3 * HZ) 121 122 /* A tun_file connects an open character device to a tuntap netdevice. It 123 * also contains all socket related structures (except sock_fprog and tap_filter) 124 * to serve as one transmit queue for tuntap device. The sock_fprog and 125 * tap_filter were kept in tun_struct since they were used for filtering for the 126 * netdevice not for a specific queue (at least I didn't see the requirement for 127 * this). 128 * 129 * RCU usage: 130 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 131 * other can only be read while rcu_read_lock or rtnl_lock is held. 132 */ 133 struct tun_file { 134 struct sock sk; 135 struct socket socket; 136 struct socket_wq wq; 137 struct tun_struct __rcu *tun; 138 struct net *net; 139 struct fasync_struct *fasync; 140 /* only used for fasnyc */ 141 unsigned int flags; 142 union { 143 u16 queue_index; 144 unsigned int ifindex; 145 }; 146 struct list_head next; 147 struct tun_struct *detached; 148 }; 149 150 struct tun_flow_entry { 151 struct hlist_node hash_link; 152 struct rcu_head rcu; 153 struct tun_struct *tun; 154 155 u32 rxhash; 156 u32 rps_rxhash; 157 int queue_index; 158 unsigned long updated; 159 }; 160 161 #define TUN_NUM_FLOW_ENTRIES 1024 162 163 /* Since the socket were moved to tun_file, to preserve the behavior of persist 164 * device, socket filter, sndbuf and vnet header size were restore when the 165 * file were attached to a persist device. 166 */ 167 struct tun_struct { 168 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 169 unsigned int numqueues; 170 unsigned int flags; 171 kuid_t owner; 172 kgid_t group; 173 174 struct net_device *dev; 175 netdev_features_t set_features; 176 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 177 NETIF_F_TSO6|NETIF_F_UFO) 178 179 int vnet_hdr_sz; 180 int sndbuf; 181 struct tap_filter txflt; 182 struct sock_fprog fprog; 183 /* protected by rtnl lock */ 184 bool filter_attached; 185 #ifdef TUN_DEBUG 186 int debug; 187 #endif 188 spinlock_t lock; 189 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 190 struct timer_list flow_gc_timer; 191 unsigned long ageing_time; 192 unsigned int numdisabled; 193 struct list_head disabled; 194 void *security; 195 u32 flow_count; 196 }; 197 198 static inline u32 tun_hashfn(u32 rxhash) 199 { 200 return rxhash & 0x3ff; 201 } 202 203 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 204 { 205 struct tun_flow_entry *e; 206 207 hlist_for_each_entry_rcu(e, head, hash_link) { 208 if (e->rxhash == rxhash) 209 return e; 210 } 211 return NULL; 212 } 213 214 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 215 struct hlist_head *head, 216 u32 rxhash, u16 queue_index) 217 { 218 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 219 220 if (e) { 221 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 222 rxhash, queue_index); 223 e->updated = jiffies; 224 e->rxhash = rxhash; 225 e->rps_rxhash = 0; 226 e->queue_index = queue_index; 227 e->tun = tun; 228 hlist_add_head_rcu(&e->hash_link, head); 229 ++tun->flow_count; 230 } 231 return e; 232 } 233 234 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 235 { 236 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 237 e->rxhash, e->queue_index); 238 sock_rps_reset_flow_hash(e->rps_rxhash); 239 hlist_del_rcu(&e->hash_link); 240 kfree_rcu(e, rcu); 241 --tun->flow_count; 242 } 243 244 static void tun_flow_flush(struct tun_struct *tun) 245 { 246 int i; 247 248 spin_lock_bh(&tun->lock); 249 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 250 struct tun_flow_entry *e; 251 struct hlist_node *n; 252 253 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 254 tun_flow_delete(tun, e); 255 } 256 spin_unlock_bh(&tun->lock); 257 } 258 259 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 260 { 261 int i; 262 263 spin_lock_bh(&tun->lock); 264 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 265 struct tun_flow_entry *e; 266 struct hlist_node *n; 267 268 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 269 if (e->queue_index == queue_index) 270 tun_flow_delete(tun, e); 271 } 272 } 273 spin_unlock_bh(&tun->lock); 274 } 275 276 static void tun_flow_cleanup(unsigned long data) 277 { 278 struct tun_struct *tun = (struct tun_struct *)data; 279 unsigned long delay = tun->ageing_time; 280 unsigned long next_timer = jiffies + delay; 281 unsigned long count = 0; 282 int i; 283 284 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 285 286 spin_lock_bh(&tun->lock); 287 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 288 struct tun_flow_entry *e; 289 struct hlist_node *n; 290 291 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 292 unsigned long this_timer; 293 count++; 294 this_timer = e->updated + delay; 295 if (time_before_eq(this_timer, jiffies)) 296 tun_flow_delete(tun, e); 297 else if (time_before(this_timer, next_timer)) 298 next_timer = this_timer; 299 } 300 } 301 302 if (count) 303 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 304 spin_unlock_bh(&tun->lock); 305 } 306 307 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 308 struct tun_file *tfile) 309 { 310 struct hlist_head *head; 311 struct tun_flow_entry *e; 312 unsigned long delay = tun->ageing_time; 313 u16 queue_index = tfile->queue_index; 314 315 if (!rxhash) 316 return; 317 else 318 head = &tun->flows[tun_hashfn(rxhash)]; 319 320 rcu_read_lock(); 321 322 /* We may get a very small possibility of OOO during switching, not 323 * worth to optimize.*/ 324 if (tun->numqueues == 1 || tfile->detached) 325 goto unlock; 326 327 e = tun_flow_find(head, rxhash); 328 if (likely(e)) { 329 /* TODO: keep queueing to old queue until it's empty? */ 330 e->queue_index = queue_index; 331 e->updated = jiffies; 332 sock_rps_record_flow_hash(e->rps_rxhash); 333 } else { 334 spin_lock_bh(&tun->lock); 335 if (!tun_flow_find(head, rxhash) && 336 tun->flow_count < MAX_TAP_FLOWS) 337 tun_flow_create(tun, head, rxhash, queue_index); 338 339 if (!timer_pending(&tun->flow_gc_timer)) 340 mod_timer(&tun->flow_gc_timer, 341 round_jiffies_up(jiffies + delay)); 342 spin_unlock_bh(&tun->lock); 343 } 344 345 unlock: 346 rcu_read_unlock(); 347 } 348 349 /** 350 * Save the hash received in the stack receive path and update the 351 * flow_hash table accordingly. 352 */ 353 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 354 { 355 if (unlikely(e->rps_rxhash != hash)) { 356 sock_rps_reset_flow_hash(e->rps_rxhash); 357 e->rps_rxhash = hash; 358 } 359 } 360 361 /* We try to identify a flow through its rxhash first. The reason that 362 * we do not check rxq no. is because some cards(e.g 82599), chooses 363 * the rxq based on the txq where the last packet of the flow comes. As 364 * the userspace application move between processors, we may get a 365 * different rxq no. here. If we could not get rxhash, then we would 366 * hope the rxq no. may help here. 367 */ 368 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, 369 void *accel_priv, select_queue_fallback_t fallback) 370 { 371 struct tun_struct *tun = netdev_priv(dev); 372 struct tun_flow_entry *e; 373 u32 txq = 0; 374 u32 numqueues = 0; 375 376 rcu_read_lock(); 377 numqueues = ACCESS_ONCE(tun->numqueues); 378 379 txq = skb_get_hash(skb); 380 if (txq) { 381 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 382 if (e) { 383 tun_flow_save_rps_rxhash(e, txq); 384 txq = e->queue_index; 385 } else 386 /* use multiply and shift instead of expensive divide */ 387 txq = ((u64)txq * numqueues) >> 32; 388 } else if (likely(skb_rx_queue_recorded(skb))) { 389 txq = skb_get_rx_queue(skb); 390 while (unlikely(txq >= numqueues)) 391 txq -= numqueues; 392 } 393 394 rcu_read_unlock(); 395 return txq; 396 } 397 398 static inline bool tun_not_capable(struct tun_struct *tun) 399 { 400 const struct cred *cred = current_cred(); 401 struct net *net = dev_net(tun->dev); 402 403 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 404 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 405 !ns_capable(net->user_ns, CAP_NET_ADMIN); 406 } 407 408 static void tun_set_real_num_queues(struct tun_struct *tun) 409 { 410 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 411 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 412 } 413 414 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 415 { 416 tfile->detached = tun; 417 list_add_tail(&tfile->next, &tun->disabled); 418 ++tun->numdisabled; 419 } 420 421 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 422 { 423 struct tun_struct *tun = tfile->detached; 424 425 tfile->detached = NULL; 426 list_del_init(&tfile->next); 427 --tun->numdisabled; 428 return tun; 429 } 430 431 static void tun_queue_purge(struct tun_file *tfile) 432 { 433 skb_queue_purge(&tfile->sk.sk_receive_queue); 434 skb_queue_purge(&tfile->sk.sk_error_queue); 435 } 436 437 static void __tun_detach(struct tun_file *tfile, bool clean) 438 { 439 struct tun_file *ntfile; 440 struct tun_struct *tun; 441 442 tun = rtnl_dereference(tfile->tun); 443 444 if (tun && !tfile->detached) { 445 u16 index = tfile->queue_index; 446 BUG_ON(index >= tun->numqueues); 447 448 rcu_assign_pointer(tun->tfiles[index], 449 tun->tfiles[tun->numqueues - 1]); 450 ntfile = rtnl_dereference(tun->tfiles[index]); 451 ntfile->queue_index = index; 452 453 --tun->numqueues; 454 if (clean) { 455 RCU_INIT_POINTER(tfile->tun, NULL); 456 sock_put(&tfile->sk); 457 } else 458 tun_disable_queue(tun, tfile); 459 460 synchronize_net(); 461 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 462 /* Drop read queue */ 463 tun_queue_purge(tfile); 464 tun_set_real_num_queues(tun); 465 } else if (tfile->detached && clean) { 466 tun = tun_enable_queue(tfile); 467 sock_put(&tfile->sk); 468 } 469 470 if (clean) { 471 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 472 netif_carrier_off(tun->dev); 473 474 if (!(tun->flags & TUN_PERSIST) && 475 tun->dev->reg_state == NETREG_REGISTERED) 476 unregister_netdevice(tun->dev); 477 } 478 479 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 480 &tfile->socket.flags)); 481 sk_release_kernel(&tfile->sk); 482 } 483 } 484 485 static void tun_detach(struct tun_file *tfile, bool clean) 486 { 487 rtnl_lock(); 488 __tun_detach(tfile, clean); 489 rtnl_unlock(); 490 } 491 492 static void tun_detach_all(struct net_device *dev) 493 { 494 struct tun_struct *tun = netdev_priv(dev); 495 struct tun_file *tfile, *tmp; 496 int i, n = tun->numqueues; 497 498 for (i = 0; i < n; i++) { 499 tfile = rtnl_dereference(tun->tfiles[i]); 500 BUG_ON(!tfile); 501 wake_up_all(&tfile->wq.wait); 502 RCU_INIT_POINTER(tfile->tun, NULL); 503 --tun->numqueues; 504 } 505 list_for_each_entry(tfile, &tun->disabled, next) { 506 wake_up_all(&tfile->wq.wait); 507 RCU_INIT_POINTER(tfile->tun, NULL); 508 } 509 BUG_ON(tun->numqueues != 0); 510 511 synchronize_net(); 512 for (i = 0; i < n; i++) { 513 tfile = rtnl_dereference(tun->tfiles[i]); 514 /* Drop read queue */ 515 tun_queue_purge(tfile); 516 sock_put(&tfile->sk); 517 } 518 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 519 tun_enable_queue(tfile); 520 tun_queue_purge(tfile); 521 sock_put(&tfile->sk); 522 } 523 BUG_ON(tun->numdisabled != 0); 524 525 if (tun->flags & TUN_PERSIST) 526 module_put(THIS_MODULE); 527 } 528 529 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) 530 { 531 struct tun_file *tfile = file->private_data; 532 int err; 533 534 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 535 if (err < 0) 536 goto out; 537 538 err = -EINVAL; 539 if (rtnl_dereference(tfile->tun) && !tfile->detached) 540 goto out; 541 542 err = -EBUSY; 543 if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1) 544 goto out; 545 546 err = -E2BIG; 547 if (!tfile->detached && 548 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 549 goto out; 550 551 err = 0; 552 553 /* Re-attach the filter to persist device */ 554 if (!skip_filter && (tun->filter_attached == true)) { 555 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 556 if (!err) 557 goto out; 558 } 559 tfile->queue_index = tun->numqueues; 560 rcu_assign_pointer(tfile->tun, tun); 561 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 562 tun->numqueues++; 563 564 if (tfile->detached) 565 tun_enable_queue(tfile); 566 else 567 sock_hold(&tfile->sk); 568 569 tun_set_real_num_queues(tun); 570 571 /* device is allowed to go away first, so no need to hold extra 572 * refcnt. 573 */ 574 575 out: 576 return err; 577 } 578 579 static struct tun_struct *__tun_get(struct tun_file *tfile) 580 { 581 struct tun_struct *tun; 582 583 rcu_read_lock(); 584 tun = rcu_dereference(tfile->tun); 585 if (tun) 586 dev_hold(tun->dev); 587 rcu_read_unlock(); 588 589 return tun; 590 } 591 592 static struct tun_struct *tun_get(struct file *file) 593 { 594 return __tun_get(file->private_data); 595 } 596 597 static void tun_put(struct tun_struct *tun) 598 { 599 dev_put(tun->dev); 600 } 601 602 /* TAP filtering */ 603 static void addr_hash_set(u32 *mask, const u8 *addr) 604 { 605 int n = ether_crc(ETH_ALEN, addr) >> 26; 606 mask[n >> 5] |= (1 << (n & 31)); 607 } 608 609 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 610 { 611 int n = ether_crc(ETH_ALEN, addr) >> 26; 612 return mask[n >> 5] & (1 << (n & 31)); 613 } 614 615 static int update_filter(struct tap_filter *filter, void __user *arg) 616 { 617 struct { u8 u[ETH_ALEN]; } *addr; 618 struct tun_filter uf; 619 int err, alen, n, nexact; 620 621 if (copy_from_user(&uf, arg, sizeof(uf))) 622 return -EFAULT; 623 624 if (!uf.count) { 625 /* Disabled */ 626 filter->count = 0; 627 return 0; 628 } 629 630 alen = ETH_ALEN * uf.count; 631 addr = kmalloc(alen, GFP_KERNEL); 632 if (!addr) 633 return -ENOMEM; 634 635 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 636 err = -EFAULT; 637 goto done; 638 } 639 640 /* The filter is updated without holding any locks. Which is 641 * perfectly safe. We disable it first and in the worst 642 * case we'll accept a few undesired packets. */ 643 filter->count = 0; 644 wmb(); 645 646 /* Use first set of addresses as an exact filter */ 647 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 648 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 649 650 nexact = n; 651 652 /* Remaining multicast addresses are hashed, 653 * unicast will leave the filter disabled. */ 654 memset(filter->mask, 0, sizeof(filter->mask)); 655 for (; n < uf.count; n++) { 656 if (!is_multicast_ether_addr(addr[n].u)) { 657 err = 0; /* no filter */ 658 goto done; 659 } 660 addr_hash_set(filter->mask, addr[n].u); 661 } 662 663 /* For ALLMULTI just set the mask to all ones. 664 * This overrides the mask populated above. */ 665 if ((uf.flags & TUN_FLT_ALLMULTI)) 666 memset(filter->mask, ~0, sizeof(filter->mask)); 667 668 /* Now enable the filter */ 669 wmb(); 670 filter->count = nexact; 671 672 /* Return the number of exact filters */ 673 err = nexact; 674 675 done: 676 kfree(addr); 677 return err; 678 } 679 680 /* Returns: 0 - drop, !=0 - accept */ 681 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 682 { 683 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 684 * at this point. */ 685 struct ethhdr *eh = (struct ethhdr *) skb->data; 686 int i; 687 688 /* Exact match */ 689 for (i = 0; i < filter->count; i++) 690 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 691 return 1; 692 693 /* Inexact match (multicast only) */ 694 if (is_multicast_ether_addr(eh->h_dest)) 695 return addr_hash_test(filter->mask, eh->h_dest); 696 697 return 0; 698 } 699 700 /* 701 * Checks whether the packet is accepted or not. 702 * Returns: 0 - drop, !=0 - accept 703 */ 704 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 705 { 706 if (!filter->count) 707 return 1; 708 709 return run_filter(filter, skb); 710 } 711 712 /* Network device part of the driver */ 713 714 static const struct ethtool_ops tun_ethtool_ops; 715 716 /* Net device detach from fd. */ 717 static void tun_net_uninit(struct net_device *dev) 718 { 719 tun_detach_all(dev); 720 } 721 722 /* Net device open. */ 723 static int tun_net_open(struct net_device *dev) 724 { 725 netif_tx_start_all_queues(dev); 726 return 0; 727 } 728 729 /* Net device close. */ 730 static int tun_net_close(struct net_device *dev) 731 { 732 netif_tx_stop_all_queues(dev); 733 return 0; 734 } 735 736 /* Net device start xmit */ 737 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 738 { 739 struct tun_struct *tun = netdev_priv(dev); 740 int txq = skb->queue_mapping; 741 struct tun_file *tfile; 742 u32 numqueues = 0; 743 744 rcu_read_lock(); 745 tfile = rcu_dereference(tun->tfiles[txq]); 746 numqueues = ACCESS_ONCE(tun->numqueues); 747 748 /* Drop packet if interface is not attached */ 749 if (txq >= numqueues) 750 goto drop; 751 752 if (numqueues == 1) { 753 /* Select queue was not called for the skbuff, so we extract the 754 * RPS hash and save it into the flow_table here. 755 */ 756 __u32 rxhash; 757 758 rxhash = skb_get_hash(skb); 759 if (rxhash) { 760 struct tun_flow_entry *e; 761 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], 762 rxhash); 763 if (e) 764 tun_flow_save_rps_rxhash(e, rxhash); 765 } 766 } 767 768 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 769 770 BUG_ON(!tfile); 771 772 /* Drop if the filter does not like it. 773 * This is a noop if the filter is disabled. 774 * Filter can be enabled only for the TAP devices. */ 775 if (!check_filter(&tun->txflt, skb)) 776 goto drop; 777 778 if (tfile->socket.sk->sk_filter && 779 sk_filter(tfile->socket.sk, skb)) 780 goto drop; 781 782 /* Limit the number of packets queued by dividing txq length with the 783 * number of queues. 784 */ 785 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues 786 >= dev->tx_queue_len) 787 goto drop; 788 789 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 790 goto drop; 791 792 if (skb->sk) { 793 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags); 794 sw_tx_timestamp(skb); 795 } 796 797 /* Orphan the skb - required as we might hang on to it 798 * for indefinite time. 799 */ 800 skb_orphan(skb); 801 802 nf_reset(skb); 803 804 /* Enqueue packet */ 805 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 806 807 /* Notify and wake up reader process */ 808 if (tfile->flags & TUN_FASYNC) 809 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 810 wake_up_interruptible_poll(&tfile->wq.wait, POLLIN | 811 POLLRDNORM | POLLRDBAND); 812 813 rcu_read_unlock(); 814 return NETDEV_TX_OK; 815 816 drop: 817 dev->stats.tx_dropped++; 818 skb_tx_error(skb); 819 kfree_skb(skb); 820 rcu_read_unlock(); 821 return NETDEV_TX_OK; 822 } 823 824 static void tun_net_mclist(struct net_device *dev) 825 { 826 /* 827 * This callback is supposed to deal with mc filter in 828 * _rx_ path and has nothing to do with the _tx_ path. 829 * In rx path we always accept everything userspace gives us. 830 */ 831 } 832 833 #define MIN_MTU 68 834 #define MAX_MTU 65535 835 836 static int 837 tun_net_change_mtu(struct net_device *dev, int new_mtu) 838 { 839 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 840 return -EINVAL; 841 dev->mtu = new_mtu; 842 return 0; 843 } 844 845 static netdev_features_t tun_net_fix_features(struct net_device *dev, 846 netdev_features_t features) 847 { 848 struct tun_struct *tun = netdev_priv(dev); 849 850 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 851 } 852 #ifdef CONFIG_NET_POLL_CONTROLLER 853 static void tun_poll_controller(struct net_device *dev) 854 { 855 /* 856 * Tun only receives frames when: 857 * 1) the char device endpoint gets data from user space 858 * 2) the tun socket gets a sendmsg call from user space 859 * Since both of those are synchronous operations, we are guaranteed 860 * never to have pending data when we poll for it 861 * so there is nothing to do here but return. 862 * We need this though so netpoll recognizes us as an interface that 863 * supports polling, which enables bridge devices in virt setups to 864 * still use netconsole 865 */ 866 return; 867 } 868 #endif 869 static const struct net_device_ops tun_netdev_ops = { 870 .ndo_uninit = tun_net_uninit, 871 .ndo_open = tun_net_open, 872 .ndo_stop = tun_net_close, 873 .ndo_start_xmit = tun_net_xmit, 874 .ndo_change_mtu = tun_net_change_mtu, 875 .ndo_fix_features = tun_net_fix_features, 876 .ndo_select_queue = tun_select_queue, 877 #ifdef CONFIG_NET_POLL_CONTROLLER 878 .ndo_poll_controller = tun_poll_controller, 879 #endif 880 }; 881 882 static const struct net_device_ops tap_netdev_ops = { 883 .ndo_uninit = tun_net_uninit, 884 .ndo_open = tun_net_open, 885 .ndo_stop = tun_net_close, 886 .ndo_start_xmit = tun_net_xmit, 887 .ndo_change_mtu = tun_net_change_mtu, 888 .ndo_fix_features = tun_net_fix_features, 889 .ndo_set_rx_mode = tun_net_mclist, 890 .ndo_set_mac_address = eth_mac_addr, 891 .ndo_validate_addr = eth_validate_addr, 892 .ndo_select_queue = tun_select_queue, 893 #ifdef CONFIG_NET_POLL_CONTROLLER 894 .ndo_poll_controller = tun_poll_controller, 895 #endif 896 }; 897 898 static void tun_flow_init(struct tun_struct *tun) 899 { 900 int i; 901 902 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 903 INIT_HLIST_HEAD(&tun->flows[i]); 904 905 tun->ageing_time = TUN_FLOW_EXPIRE; 906 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 907 mod_timer(&tun->flow_gc_timer, 908 round_jiffies_up(jiffies + tun->ageing_time)); 909 } 910 911 static void tun_flow_uninit(struct tun_struct *tun) 912 { 913 del_timer_sync(&tun->flow_gc_timer); 914 tun_flow_flush(tun); 915 } 916 917 /* Initialize net device. */ 918 static void tun_net_init(struct net_device *dev) 919 { 920 struct tun_struct *tun = netdev_priv(dev); 921 922 switch (tun->flags & TUN_TYPE_MASK) { 923 case TUN_TUN_DEV: 924 dev->netdev_ops = &tun_netdev_ops; 925 926 /* Point-to-Point TUN Device */ 927 dev->hard_header_len = 0; 928 dev->addr_len = 0; 929 dev->mtu = 1500; 930 931 /* Zero header length */ 932 dev->type = ARPHRD_NONE; 933 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 934 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 935 break; 936 937 case TUN_TAP_DEV: 938 dev->netdev_ops = &tap_netdev_ops; 939 /* Ethernet TAP Device */ 940 ether_setup(dev); 941 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 942 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 943 944 eth_hw_addr_random(dev); 945 946 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 947 break; 948 } 949 } 950 951 /* Character device part */ 952 953 /* Poll */ 954 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 955 { 956 struct tun_file *tfile = file->private_data; 957 struct tun_struct *tun = __tun_get(tfile); 958 struct sock *sk; 959 unsigned int mask = 0; 960 961 if (!tun) 962 return POLLERR; 963 964 sk = tfile->socket.sk; 965 966 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 967 968 poll_wait(file, &tfile->wq.wait, wait); 969 970 if (!skb_queue_empty(&sk->sk_receive_queue)) 971 mask |= POLLIN | POLLRDNORM; 972 973 if (sock_writeable(sk) || 974 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 975 sock_writeable(sk))) 976 mask |= POLLOUT | POLLWRNORM; 977 978 if (tun->dev->reg_state != NETREG_REGISTERED) 979 mask = POLLERR; 980 981 tun_put(tun); 982 return mask; 983 } 984 985 /* prepad is the amount to reserve at front. len is length after that. 986 * linear is a hint as to how much to copy (usually headers). */ 987 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 988 size_t prepad, size_t len, 989 size_t linear, int noblock) 990 { 991 struct sock *sk = tfile->socket.sk; 992 struct sk_buff *skb; 993 int err; 994 995 /* Under a page? Don't bother with paged skb. */ 996 if (prepad + len < PAGE_SIZE || !linear) 997 linear = len; 998 999 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 1000 &err, 0); 1001 if (!skb) 1002 return ERR_PTR(err); 1003 1004 skb_reserve(skb, prepad); 1005 skb_put(skb, linear); 1006 skb->data_len = len - linear; 1007 skb->len += len - linear; 1008 1009 return skb; 1010 } 1011 1012 /* Get packet from user space buffer */ 1013 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1014 void *msg_control, const struct iovec *iv, 1015 size_t total_len, size_t count, int noblock) 1016 { 1017 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1018 struct sk_buff *skb; 1019 size_t len = total_len, align = NET_SKB_PAD, linear; 1020 struct virtio_net_hdr gso = { 0 }; 1021 int good_linear; 1022 int offset = 0; 1023 int copylen; 1024 bool zerocopy = false; 1025 int err; 1026 u32 rxhash; 1027 1028 if (!(tun->flags & TUN_NO_PI)) { 1029 if (len < sizeof(pi)) 1030 return -EINVAL; 1031 len -= sizeof(pi); 1032 1033 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) 1034 return -EFAULT; 1035 offset += sizeof(pi); 1036 } 1037 1038 if (tun->flags & TUN_VNET_HDR) { 1039 if (len < tun->vnet_hdr_sz) 1040 return -EINVAL; 1041 len -= tun->vnet_hdr_sz; 1042 1043 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) 1044 return -EFAULT; 1045 1046 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1047 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) 1048 gso.hdr_len = gso.csum_start + gso.csum_offset + 2; 1049 1050 if (gso.hdr_len > len) 1051 return -EINVAL; 1052 offset += tun->vnet_hdr_sz; 1053 } 1054 1055 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { 1056 align += NET_IP_ALIGN; 1057 if (unlikely(len < ETH_HLEN || 1058 (gso.hdr_len && gso.hdr_len < ETH_HLEN))) 1059 return -EINVAL; 1060 } 1061 1062 good_linear = SKB_MAX_HEAD(align); 1063 1064 if (msg_control) { 1065 /* There are 256 bytes to be copied in skb, so there is 1066 * enough room for skb expand head in case it is used. 1067 * The rest of the buffer is mapped from userspace. 1068 */ 1069 copylen = gso.hdr_len ? gso.hdr_len : GOODCOPY_LEN; 1070 if (copylen > good_linear) 1071 copylen = good_linear; 1072 linear = copylen; 1073 if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS) 1074 zerocopy = true; 1075 } 1076 1077 if (!zerocopy) { 1078 copylen = len; 1079 if (gso.hdr_len > good_linear) 1080 linear = good_linear; 1081 else 1082 linear = gso.hdr_len; 1083 } 1084 1085 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1086 if (IS_ERR(skb)) { 1087 if (PTR_ERR(skb) != -EAGAIN) 1088 tun->dev->stats.rx_dropped++; 1089 return PTR_ERR(skb); 1090 } 1091 1092 if (zerocopy) 1093 err = zerocopy_sg_from_iovec(skb, iv, offset, count); 1094 else { 1095 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len); 1096 if (!err && msg_control) { 1097 struct ubuf_info *uarg = msg_control; 1098 uarg->callback(uarg, false); 1099 } 1100 } 1101 1102 if (err) { 1103 tun->dev->stats.rx_dropped++; 1104 kfree_skb(skb); 1105 return -EFAULT; 1106 } 1107 1108 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1109 if (!skb_partial_csum_set(skb, gso.csum_start, 1110 gso.csum_offset)) { 1111 tun->dev->stats.rx_frame_errors++; 1112 kfree_skb(skb); 1113 return -EINVAL; 1114 } 1115 } 1116 1117 switch (tun->flags & TUN_TYPE_MASK) { 1118 case TUN_TUN_DEV: 1119 if (tun->flags & TUN_NO_PI) { 1120 switch (skb->data[0] & 0xf0) { 1121 case 0x40: 1122 pi.proto = htons(ETH_P_IP); 1123 break; 1124 case 0x60: 1125 pi.proto = htons(ETH_P_IPV6); 1126 break; 1127 default: 1128 tun->dev->stats.rx_dropped++; 1129 kfree_skb(skb); 1130 return -EINVAL; 1131 } 1132 } 1133 1134 skb_reset_mac_header(skb); 1135 skb->protocol = pi.proto; 1136 skb->dev = tun->dev; 1137 break; 1138 case TUN_TAP_DEV: 1139 skb->protocol = eth_type_trans(skb, tun->dev); 1140 break; 1141 } 1142 1143 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1144 pr_debug("GSO!\n"); 1145 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1146 case VIRTIO_NET_HDR_GSO_TCPV4: 1147 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1148 break; 1149 case VIRTIO_NET_HDR_GSO_TCPV6: 1150 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1151 break; 1152 case VIRTIO_NET_HDR_GSO_UDP: 1153 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1154 break; 1155 default: 1156 tun->dev->stats.rx_frame_errors++; 1157 kfree_skb(skb); 1158 return -EINVAL; 1159 } 1160 1161 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1162 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1163 1164 skb_shinfo(skb)->gso_size = gso.gso_size; 1165 if (skb_shinfo(skb)->gso_size == 0) { 1166 tun->dev->stats.rx_frame_errors++; 1167 kfree_skb(skb); 1168 return -EINVAL; 1169 } 1170 1171 /* Header must be checked, and gso_segs computed. */ 1172 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1173 skb_shinfo(skb)->gso_segs = 0; 1174 } 1175 1176 /* copy skb_ubuf_info for callback when skb has no error */ 1177 if (zerocopy) { 1178 skb_shinfo(skb)->destructor_arg = msg_control; 1179 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1180 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1181 } 1182 1183 skb_reset_network_header(skb); 1184 skb_probe_transport_header(skb, 0); 1185 1186 rxhash = skb_get_hash(skb); 1187 netif_rx_ni(skb); 1188 1189 tun->dev->stats.rx_packets++; 1190 tun->dev->stats.rx_bytes += len; 1191 1192 tun_flow_update(tun, rxhash, tfile); 1193 return total_len; 1194 } 1195 1196 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 1197 unsigned long count, loff_t pos) 1198 { 1199 struct file *file = iocb->ki_filp; 1200 struct tun_struct *tun = tun_get(file); 1201 struct tun_file *tfile = file->private_data; 1202 ssize_t result; 1203 1204 if (!tun) 1205 return -EBADFD; 1206 1207 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count); 1208 1209 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count), 1210 count, file->f_flags & O_NONBLOCK); 1211 1212 tun_put(tun); 1213 return result; 1214 } 1215 1216 /* Put packet to the user space buffer */ 1217 static ssize_t tun_put_user(struct tun_struct *tun, 1218 struct tun_file *tfile, 1219 struct sk_buff *skb, 1220 const struct iovec *iv, int len) 1221 { 1222 struct tun_pi pi = { 0, skb->protocol }; 1223 ssize_t total = 0; 1224 int vlan_offset = 0, copied; 1225 1226 if (!(tun->flags & TUN_NO_PI)) { 1227 if ((len -= sizeof(pi)) < 0) 1228 return -EINVAL; 1229 1230 if (len < skb->len) { 1231 /* Packet will be striped */ 1232 pi.flags |= TUN_PKT_STRIP; 1233 } 1234 1235 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi))) 1236 return -EFAULT; 1237 total += sizeof(pi); 1238 } 1239 1240 if (tun->flags & TUN_VNET_HDR) { 1241 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1242 if ((len -= tun->vnet_hdr_sz) < 0) 1243 return -EINVAL; 1244 1245 if (skb_is_gso(skb)) { 1246 struct skb_shared_info *sinfo = skb_shinfo(skb); 1247 1248 /* This is a hint as to how much should be linear. */ 1249 gso.hdr_len = skb_headlen(skb); 1250 gso.gso_size = sinfo->gso_size; 1251 if (sinfo->gso_type & SKB_GSO_TCPV4) 1252 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1253 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1254 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1255 else if (sinfo->gso_type & SKB_GSO_UDP) 1256 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1257 else { 1258 pr_err("unexpected GSO type: " 1259 "0x%x, gso_size %d, hdr_len %d\n", 1260 sinfo->gso_type, gso.gso_size, 1261 gso.hdr_len); 1262 print_hex_dump(KERN_ERR, "tun: ", 1263 DUMP_PREFIX_NONE, 1264 16, 1, skb->head, 1265 min((int)gso.hdr_len, 64), true); 1266 WARN_ON_ONCE(1); 1267 return -EINVAL; 1268 } 1269 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1270 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1271 } else 1272 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1273 1274 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1275 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1276 gso.csum_start = skb_checksum_start_offset(skb); 1277 gso.csum_offset = skb->csum_offset; 1278 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1279 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1280 } /* else everything is zero */ 1281 1282 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, 1283 sizeof(gso)))) 1284 return -EFAULT; 1285 total += tun->vnet_hdr_sz; 1286 } 1287 1288 copied = total; 1289 total += skb->len; 1290 if (!vlan_tx_tag_present(skb)) { 1291 len = min_t(int, skb->len, len); 1292 } else { 1293 int copy, ret; 1294 struct { 1295 __be16 h_vlan_proto; 1296 __be16 h_vlan_TCI; 1297 } veth; 1298 1299 veth.h_vlan_proto = skb->vlan_proto; 1300 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 1301 1302 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1303 len = min_t(int, skb->len + VLAN_HLEN, len); 1304 total += VLAN_HLEN; 1305 1306 copy = min_t(int, vlan_offset, len); 1307 ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); 1308 len -= copy; 1309 copied += copy; 1310 if (ret || !len) 1311 goto done; 1312 1313 copy = min_t(int, sizeof(veth), len); 1314 ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy); 1315 len -= copy; 1316 copied += copy; 1317 if (ret || !len) 1318 goto done; 1319 } 1320 1321 skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len); 1322 1323 done: 1324 tun->dev->stats.tx_packets++; 1325 tun->dev->stats.tx_bytes += len; 1326 1327 return total; 1328 } 1329 1330 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1331 const struct iovec *iv, ssize_t len, int noblock) 1332 { 1333 DECLARE_WAITQUEUE(wait, current); 1334 struct sk_buff *skb; 1335 ssize_t ret = 0; 1336 1337 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1338 1339 if (unlikely(!noblock)) 1340 add_wait_queue(&tfile->wq.wait, &wait); 1341 while (len) { 1342 if (unlikely(!noblock)) 1343 current->state = TASK_INTERRUPTIBLE; 1344 1345 /* Read frames from the queue */ 1346 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) { 1347 if (noblock) { 1348 ret = -EAGAIN; 1349 break; 1350 } 1351 if (signal_pending(current)) { 1352 ret = -ERESTARTSYS; 1353 break; 1354 } 1355 if (tun->dev->reg_state != NETREG_REGISTERED) { 1356 ret = -EIO; 1357 break; 1358 } 1359 1360 /* Nothing to read, let's sleep */ 1361 schedule(); 1362 continue; 1363 } 1364 1365 ret = tun_put_user(tun, tfile, skb, iv, len); 1366 kfree_skb(skb); 1367 break; 1368 } 1369 1370 if (unlikely(!noblock)) { 1371 current->state = TASK_RUNNING; 1372 remove_wait_queue(&tfile->wq.wait, &wait); 1373 } 1374 1375 return ret; 1376 } 1377 1378 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 1379 unsigned long count, loff_t pos) 1380 { 1381 struct file *file = iocb->ki_filp; 1382 struct tun_file *tfile = file->private_data; 1383 struct tun_struct *tun = __tun_get(tfile); 1384 ssize_t len, ret; 1385 1386 if (!tun) 1387 return -EBADFD; 1388 len = iov_length(iv, count); 1389 if (len < 0) { 1390 ret = -EINVAL; 1391 goto out; 1392 } 1393 1394 ret = tun_do_read(tun, tfile, iv, len, 1395 file->f_flags & O_NONBLOCK); 1396 ret = min_t(ssize_t, ret, len); 1397 if (ret > 0) 1398 iocb->ki_pos = ret; 1399 out: 1400 tun_put(tun); 1401 return ret; 1402 } 1403 1404 static void tun_free_netdev(struct net_device *dev) 1405 { 1406 struct tun_struct *tun = netdev_priv(dev); 1407 1408 BUG_ON(!(list_empty(&tun->disabled))); 1409 tun_flow_uninit(tun); 1410 security_tun_dev_free_security(tun->security); 1411 free_netdev(dev); 1412 } 1413 1414 static void tun_setup(struct net_device *dev) 1415 { 1416 struct tun_struct *tun = netdev_priv(dev); 1417 1418 tun->owner = INVALID_UID; 1419 tun->group = INVALID_GID; 1420 1421 dev->ethtool_ops = &tun_ethtool_ops; 1422 dev->destructor = tun_free_netdev; 1423 } 1424 1425 /* Trivial set of netlink ops to allow deleting tun or tap 1426 * device with netlink. 1427 */ 1428 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1429 { 1430 return -EINVAL; 1431 } 1432 1433 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1434 .kind = DRV_NAME, 1435 .priv_size = sizeof(struct tun_struct), 1436 .setup = tun_setup, 1437 .validate = tun_validate, 1438 }; 1439 1440 static void tun_sock_write_space(struct sock *sk) 1441 { 1442 struct tun_file *tfile; 1443 wait_queue_head_t *wqueue; 1444 1445 if (!sock_writeable(sk)) 1446 return; 1447 1448 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1449 return; 1450 1451 wqueue = sk_sleep(sk); 1452 if (wqueue && waitqueue_active(wqueue)) 1453 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1454 POLLWRNORM | POLLWRBAND); 1455 1456 tfile = container_of(sk, struct tun_file, sk); 1457 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1458 } 1459 1460 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1461 struct msghdr *m, size_t total_len) 1462 { 1463 int ret; 1464 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1465 struct tun_struct *tun = __tun_get(tfile); 1466 1467 if (!tun) 1468 return -EBADFD; 1469 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len, 1470 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); 1471 tun_put(tun); 1472 return ret; 1473 } 1474 1475 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1476 struct msghdr *m, size_t total_len, 1477 int flags) 1478 { 1479 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1480 struct tun_struct *tun = __tun_get(tfile); 1481 int ret; 1482 1483 if (!tun) 1484 return -EBADFD; 1485 1486 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1487 ret = -EINVAL; 1488 goto out; 1489 } 1490 if (flags & MSG_ERRQUEUE) { 1491 ret = sock_recv_errqueue(sock->sk, m, total_len, 1492 SOL_PACKET, TUN_TX_TIMESTAMP); 1493 goto out; 1494 } 1495 ret = tun_do_read(tun, tfile, m->msg_iov, total_len, 1496 flags & MSG_DONTWAIT); 1497 if (ret > total_len) { 1498 m->msg_flags |= MSG_TRUNC; 1499 ret = flags & MSG_TRUNC ? ret : total_len; 1500 } 1501 out: 1502 tun_put(tun); 1503 return ret; 1504 } 1505 1506 static int tun_release(struct socket *sock) 1507 { 1508 if (sock->sk) 1509 sock_put(sock->sk); 1510 return 0; 1511 } 1512 1513 /* Ops structure to mimic raw sockets with tun */ 1514 static const struct proto_ops tun_socket_ops = { 1515 .sendmsg = tun_sendmsg, 1516 .recvmsg = tun_recvmsg, 1517 .release = tun_release, 1518 }; 1519 1520 static struct proto tun_proto = { 1521 .name = "tun", 1522 .owner = THIS_MODULE, 1523 .obj_size = sizeof(struct tun_file), 1524 }; 1525 1526 static int tun_flags(struct tun_struct *tun) 1527 { 1528 int flags = 0; 1529 1530 if (tun->flags & TUN_TUN_DEV) 1531 flags |= IFF_TUN; 1532 else 1533 flags |= IFF_TAP; 1534 1535 if (tun->flags & TUN_NO_PI) 1536 flags |= IFF_NO_PI; 1537 1538 /* This flag has no real effect. We track the value for backwards 1539 * compatibility. 1540 */ 1541 if (tun->flags & TUN_ONE_QUEUE) 1542 flags |= IFF_ONE_QUEUE; 1543 1544 if (tun->flags & TUN_VNET_HDR) 1545 flags |= IFF_VNET_HDR; 1546 1547 if (tun->flags & TUN_TAP_MQ) 1548 flags |= IFF_MULTI_QUEUE; 1549 1550 if (tun->flags & TUN_PERSIST) 1551 flags |= IFF_PERSIST; 1552 1553 return flags; 1554 } 1555 1556 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1557 char *buf) 1558 { 1559 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1560 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1561 } 1562 1563 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1564 char *buf) 1565 { 1566 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1567 return uid_valid(tun->owner)? 1568 sprintf(buf, "%u\n", 1569 from_kuid_munged(current_user_ns(), tun->owner)): 1570 sprintf(buf, "-1\n"); 1571 } 1572 1573 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1574 char *buf) 1575 { 1576 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1577 return gid_valid(tun->group) ? 1578 sprintf(buf, "%u\n", 1579 from_kgid_munged(current_user_ns(), tun->group)): 1580 sprintf(buf, "-1\n"); 1581 } 1582 1583 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1584 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1585 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1586 1587 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1588 { 1589 struct tun_struct *tun; 1590 struct tun_file *tfile = file->private_data; 1591 struct net_device *dev; 1592 int err; 1593 1594 if (tfile->detached) 1595 return -EINVAL; 1596 1597 dev = __dev_get_by_name(net, ifr->ifr_name); 1598 if (dev) { 1599 if (ifr->ifr_flags & IFF_TUN_EXCL) 1600 return -EBUSY; 1601 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1602 tun = netdev_priv(dev); 1603 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1604 tun = netdev_priv(dev); 1605 else 1606 return -EINVAL; 1607 1608 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1609 !!(tun->flags & TUN_TAP_MQ)) 1610 return -EINVAL; 1611 1612 if (tun_not_capable(tun)) 1613 return -EPERM; 1614 err = security_tun_dev_open(tun->security); 1615 if (err < 0) 1616 return err; 1617 1618 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1619 if (err < 0) 1620 return err; 1621 1622 if (tun->flags & TUN_TAP_MQ && 1623 (tun->numqueues + tun->numdisabled > 1)) { 1624 /* One or more queue has already been attached, no need 1625 * to initialize the device again. 1626 */ 1627 return 0; 1628 } 1629 } 1630 else { 1631 char *name; 1632 unsigned long flags = 0; 1633 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1634 MAX_TAP_QUEUES : 1; 1635 1636 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1637 return -EPERM; 1638 err = security_tun_dev_create(); 1639 if (err < 0) 1640 return err; 1641 1642 /* Set dev type */ 1643 if (ifr->ifr_flags & IFF_TUN) { 1644 /* TUN device */ 1645 flags |= TUN_TUN_DEV; 1646 name = "tun%d"; 1647 } else if (ifr->ifr_flags & IFF_TAP) { 1648 /* TAP device */ 1649 flags |= TUN_TAP_DEV; 1650 name = "tap%d"; 1651 } else 1652 return -EINVAL; 1653 1654 if (*ifr->ifr_name) 1655 name = ifr->ifr_name; 1656 1657 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1658 tun_setup, queues, queues); 1659 1660 if (!dev) 1661 return -ENOMEM; 1662 1663 dev_net_set(dev, net); 1664 dev->rtnl_link_ops = &tun_link_ops; 1665 dev->ifindex = tfile->ifindex; 1666 1667 tun = netdev_priv(dev); 1668 tun->dev = dev; 1669 tun->flags = flags; 1670 tun->txflt.count = 0; 1671 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1672 1673 tun->filter_attached = false; 1674 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1675 1676 spin_lock_init(&tun->lock); 1677 1678 err = security_tun_dev_alloc_security(&tun->security); 1679 if (err < 0) 1680 goto err_free_dev; 1681 1682 tun_net_init(dev); 1683 tun_flow_init(tun); 1684 1685 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1686 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1687 NETIF_F_HW_VLAN_STAG_TX; 1688 dev->features = dev->hw_features; 1689 dev->vlan_features = dev->features & 1690 ~(NETIF_F_HW_VLAN_CTAG_TX | 1691 NETIF_F_HW_VLAN_STAG_TX); 1692 1693 INIT_LIST_HEAD(&tun->disabled); 1694 err = tun_attach(tun, file, false); 1695 if (err < 0) 1696 goto err_free_flow; 1697 1698 err = register_netdevice(tun->dev); 1699 if (err < 0) 1700 goto err_detach; 1701 1702 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1703 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1704 device_create_file(&tun->dev->dev, &dev_attr_group)) 1705 pr_err("Failed to create tun sysfs files\n"); 1706 } 1707 1708 netif_carrier_on(tun->dev); 1709 1710 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1711 1712 if (ifr->ifr_flags & IFF_NO_PI) 1713 tun->flags |= TUN_NO_PI; 1714 else 1715 tun->flags &= ~TUN_NO_PI; 1716 1717 /* This flag has no real effect. We track the value for backwards 1718 * compatibility. 1719 */ 1720 if (ifr->ifr_flags & IFF_ONE_QUEUE) 1721 tun->flags |= TUN_ONE_QUEUE; 1722 else 1723 tun->flags &= ~TUN_ONE_QUEUE; 1724 1725 if (ifr->ifr_flags & IFF_VNET_HDR) 1726 tun->flags |= TUN_VNET_HDR; 1727 else 1728 tun->flags &= ~TUN_VNET_HDR; 1729 1730 if (ifr->ifr_flags & IFF_MULTI_QUEUE) 1731 tun->flags |= TUN_TAP_MQ; 1732 else 1733 tun->flags &= ~TUN_TAP_MQ; 1734 1735 /* Make sure persistent devices do not get stuck in 1736 * xoff state. 1737 */ 1738 if (netif_running(tun->dev)) 1739 netif_tx_wake_all_queues(tun->dev); 1740 1741 strcpy(ifr->ifr_name, tun->dev->name); 1742 return 0; 1743 1744 err_detach: 1745 tun_detach_all(dev); 1746 err_free_flow: 1747 tun_flow_uninit(tun); 1748 security_tun_dev_free_security(tun->security); 1749 err_free_dev: 1750 free_netdev(dev); 1751 return err; 1752 } 1753 1754 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1755 struct ifreq *ifr) 1756 { 1757 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1758 1759 strcpy(ifr->ifr_name, tun->dev->name); 1760 1761 ifr->ifr_flags = tun_flags(tun); 1762 1763 } 1764 1765 /* This is like a cut-down ethtool ops, except done via tun fd so no 1766 * privs required. */ 1767 static int set_offload(struct tun_struct *tun, unsigned long arg) 1768 { 1769 netdev_features_t features = 0; 1770 1771 if (arg & TUN_F_CSUM) { 1772 features |= NETIF_F_HW_CSUM; 1773 arg &= ~TUN_F_CSUM; 1774 1775 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1776 if (arg & TUN_F_TSO_ECN) { 1777 features |= NETIF_F_TSO_ECN; 1778 arg &= ~TUN_F_TSO_ECN; 1779 } 1780 if (arg & TUN_F_TSO4) 1781 features |= NETIF_F_TSO; 1782 if (arg & TUN_F_TSO6) 1783 features |= NETIF_F_TSO6; 1784 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1785 } 1786 1787 if (arg & TUN_F_UFO) { 1788 features |= NETIF_F_UFO; 1789 arg &= ~TUN_F_UFO; 1790 } 1791 } 1792 1793 /* This gives the user a way to test for new features in future by 1794 * trying to set them. */ 1795 if (arg) 1796 return -EINVAL; 1797 1798 tun->set_features = features; 1799 netdev_update_features(tun->dev); 1800 1801 return 0; 1802 } 1803 1804 static void tun_detach_filter(struct tun_struct *tun, int n) 1805 { 1806 int i; 1807 struct tun_file *tfile; 1808 1809 for (i = 0; i < n; i++) { 1810 tfile = rtnl_dereference(tun->tfiles[i]); 1811 sk_detach_filter(tfile->socket.sk); 1812 } 1813 1814 tun->filter_attached = false; 1815 } 1816 1817 static int tun_attach_filter(struct tun_struct *tun) 1818 { 1819 int i, ret = 0; 1820 struct tun_file *tfile; 1821 1822 for (i = 0; i < tun->numqueues; i++) { 1823 tfile = rtnl_dereference(tun->tfiles[i]); 1824 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1825 if (ret) { 1826 tun_detach_filter(tun, i); 1827 return ret; 1828 } 1829 } 1830 1831 tun->filter_attached = true; 1832 return ret; 1833 } 1834 1835 static void tun_set_sndbuf(struct tun_struct *tun) 1836 { 1837 struct tun_file *tfile; 1838 int i; 1839 1840 for (i = 0; i < tun->numqueues; i++) { 1841 tfile = rtnl_dereference(tun->tfiles[i]); 1842 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1843 } 1844 } 1845 1846 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1847 { 1848 struct tun_file *tfile = file->private_data; 1849 struct tun_struct *tun; 1850 int ret = 0; 1851 1852 rtnl_lock(); 1853 1854 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1855 tun = tfile->detached; 1856 if (!tun) { 1857 ret = -EINVAL; 1858 goto unlock; 1859 } 1860 ret = security_tun_dev_attach_queue(tun->security); 1861 if (ret < 0) 1862 goto unlock; 1863 ret = tun_attach(tun, file, false); 1864 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1865 tun = rtnl_dereference(tfile->tun); 1866 if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) 1867 ret = -EINVAL; 1868 else 1869 __tun_detach(tfile, false); 1870 } else 1871 ret = -EINVAL; 1872 1873 unlock: 1874 rtnl_unlock(); 1875 return ret; 1876 } 1877 1878 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1879 unsigned long arg, int ifreq_len) 1880 { 1881 struct tun_file *tfile = file->private_data; 1882 struct tun_struct *tun; 1883 void __user* argp = (void __user*)arg; 1884 struct ifreq ifr; 1885 kuid_t owner; 1886 kgid_t group; 1887 int sndbuf; 1888 int vnet_hdr_sz; 1889 unsigned int ifindex; 1890 int ret; 1891 1892 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1893 if (copy_from_user(&ifr, argp, ifreq_len)) 1894 return -EFAULT; 1895 } else { 1896 memset(&ifr, 0, sizeof(ifr)); 1897 } 1898 if (cmd == TUNGETFEATURES) { 1899 /* Currently this just means: "what IFF flags are valid?". 1900 * This is needed because we never checked for invalid flags on 1901 * TUNSETIFF. */ 1902 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | 1903 IFF_VNET_HDR | IFF_MULTI_QUEUE, 1904 (unsigned int __user*)argp); 1905 } else if (cmd == TUNSETQUEUE) 1906 return tun_set_queue(file, &ifr); 1907 1908 ret = 0; 1909 rtnl_lock(); 1910 1911 tun = __tun_get(tfile); 1912 if (cmd == TUNSETIFF && !tun) { 1913 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1914 1915 ret = tun_set_iff(tfile->net, file, &ifr); 1916 1917 if (ret) 1918 goto unlock; 1919 1920 if (copy_to_user(argp, &ifr, ifreq_len)) 1921 ret = -EFAULT; 1922 goto unlock; 1923 } 1924 if (cmd == TUNSETIFINDEX) { 1925 ret = -EPERM; 1926 if (tun) 1927 goto unlock; 1928 1929 ret = -EFAULT; 1930 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1931 goto unlock; 1932 1933 ret = 0; 1934 tfile->ifindex = ifindex; 1935 goto unlock; 1936 } 1937 1938 ret = -EBADFD; 1939 if (!tun) 1940 goto unlock; 1941 1942 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1943 1944 ret = 0; 1945 switch (cmd) { 1946 case TUNGETIFF: 1947 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1948 1949 if (tfile->detached) 1950 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1951 if (!tfile->socket.sk->sk_filter) 1952 ifr.ifr_flags |= IFF_NOFILTER; 1953 1954 if (copy_to_user(argp, &ifr, ifreq_len)) 1955 ret = -EFAULT; 1956 break; 1957 1958 case TUNSETNOCSUM: 1959 /* Disable/Enable checksum */ 1960 1961 /* [unimplemented] */ 1962 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1963 arg ? "disabled" : "enabled"); 1964 break; 1965 1966 case TUNSETPERSIST: 1967 /* Disable/Enable persist mode. Keep an extra reference to the 1968 * module to prevent the module being unprobed. 1969 */ 1970 if (arg && !(tun->flags & TUN_PERSIST)) { 1971 tun->flags |= TUN_PERSIST; 1972 __module_get(THIS_MODULE); 1973 } 1974 if (!arg && (tun->flags & TUN_PERSIST)) { 1975 tun->flags &= ~TUN_PERSIST; 1976 module_put(THIS_MODULE); 1977 } 1978 1979 tun_debug(KERN_INFO, tun, "persist %s\n", 1980 arg ? "enabled" : "disabled"); 1981 break; 1982 1983 case TUNSETOWNER: 1984 /* Set owner of the device */ 1985 owner = make_kuid(current_user_ns(), arg); 1986 if (!uid_valid(owner)) { 1987 ret = -EINVAL; 1988 break; 1989 } 1990 tun->owner = owner; 1991 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1992 from_kuid(&init_user_ns, tun->owner)); 1993 break; 1994 1995 case TUNSETGROUP: 1996 /* Set group of the device */ 1997 group = make_kgid(current_user_ns(), arg); 1998 if (!gid_valid(group)) { 1999 ret = -EINVAL; 2000 break; 2001 } 2002 tun->group = group; 2003 tun_debug(KERN_INFO, tun, "group set to %u\n", 2004 from_kgid(&init_user_ns, tun->group)); 2005 break; 2006 2007 case TUNSETLINK: 2008 /* Only allow setting the type when the interface is down */ 2009 if (tun->dev->flags & IFF_UP) { 2010 tun_debug(KERN_INFO, tun, 2011 "Linktype set failed because interface is up\n"); 2012 ret = -EBUSY; 2013 } else { 2014 tun->dev->type = (int) arg; 2015 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 2016 tun->dev->type); 2017 ret = 0; 2018 } 2019 break; 2020 2021 #ifdef TUN_DEBUG 2022 case TUNSETDEBUG: 2023 tun->debug = arg; 2024 break; 2025 #endif 2026 case TUNSETOFFLOAD: 2027 ret = set_offload(tun, arg); 2028 break; 2029 2030 case TUNSETTXFILTER: 2031 /* Can be set only for TAPs */ 2032 ret = -EINVAL; 2033 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2034 break; 2035 ret = update_filter(&tun->txflt, (void __user *)arg); 2036 break; 2037 2038 case SIOCGIFHWADDR: 2039 /* Get hw address */ 2040 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 2041 ifr.ifr_hwaddr.sa_family = tun->dev->type; 2042 if (copy_to_user(argp, &ifr, ifreq_len)) 2043 ret = -EFAULT; 2044 break; 2045 2046 case SIOCSIFHWADDR: 2047 /* Set hw address */ 2048 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 2049 ifr.ifr_hwaddr.sa_data); 2050 2051 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2052 break; 2053 2054 case TUNGETSNDBUF: 2055 sndbuf = tfile->socket.sk->sk_sndbuf; 2056 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2057 ret = -EFAULT; 2058 break; 2059 2060 case TUNSETSNDBUF: 2061 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2062 ret = -EFAULT; 2063 break; 2064 } 2065 2066 tun->sndbuf = sndbuf; 2067 tun_set_sndbuf(tun); 2068 break; 2069 2070 case TUNGETVNETHDRSZ: 2071 vnet_hdr_sz = tun->vnet_hdr_sz; 2072 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2073 ret = -EFAULT; 2074 break; 2075 2076 case TUNSETVNETHDRSZ: 2077 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2078 ret = -EFAULT; 2079 break; 2080 } 2081 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2082 ret = -EINVAL; 2083 break; 2084 } 2085 2086 tun->vnet_hdr_sz = vnet_hdr_sz; 2087 break; 2088 2089 case TUNATTACHFILTER: 2090 /* Can be set only for TAPs */ 2091 ret = -EINVAL; 2092 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2093 break; 2094 ret = -EFAULT; 2095 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2096 break; 2097 2098 ret = tun_attach_filter(tun); 2099 break; 2100 2101 case TUNDETACHFILTER: 2102 /* Can be set only for TAPs */ 2103 ret = -EINVAL; 2104 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2105 break; 2106 ret = 0; 2107 tun_detach_filter(tun, tun->numqueues); 2108 break; 2109 2110 case TUNGETFILTER: 2111 ret = -EINVAL; 2112 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2113 break; 2114 ret = -EFAULT; 2115 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2116 break; 2117 ret = 0; 2118 break; 2119 2120 default: 2121 ret = -EINVAL; 2122 break; 2123 } 2124 2125 unlock: 2126 rtnl_unlock(); 2127 if (tun) 2128 tun_put(tun); 2129 return ret; 2130 } 2131 2132 static long tun_chr_ioctl(struct file *file, 2133 unsigned int cmd, unsigned long arg) 2134 { 2135 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2136 } 2137 2138 #ifdef CONFIG_COMPAT 2139 static long tun_chr_compat_ioctl(struct file *file, 2140 unsigned int cmd, unsigned long arg) 2141 { 2142 switch (cmd) { 2143 case TUNSETIFF: 2144 case TUNGETIFF: 2145 case TUNSETTXFILTER: 2146 case TUNGETSNDBUF: 2147 case TUNSETSNDBUF: 2148 case SIOCGIFHWADDR: 2149 case SIOCSIFHWADDR: 2150 arg = (unsigned long)compat_ptr(arg); 2151 break; 2152 default: 2153 arg = (compat_ulong_t)arg; 2154 break; 2155 } 2156 2157 /* 2158 * compat_ifreq is shorter than ifreq, so we must not access beyond 2159 * the end of that structure. All fields that are used in this 2160 * driver are compatible though, we don't need to convert the 2161 * contents. 2162 */ 2163 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2164 } 2165 #endif /* CONFIG_COMPAT */ 2166 2167 static int tun_chr_fasync(int fd, struct file *file, int on) 2168 { 2169 struct tun_file *tfile = file->private_data; 2170 int ret; 2171 2172 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2173 goto out; 2174 2175 if (on) { 2176 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2177 if (ret) 2178 goto out; 2179 tfile->flags |= TUN_FASYNC; 2180 } else 2181 tfile->flags &= ~TUN_FASYNC; 2182 ret = 0; 2183 out: 2184 return ret; 2185 } 2186 2187 static int tun_chr_open(struct inode *inode, struct file * file) 2188 { 2189 struct tun_file *tfile; 2190 2191 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2192 2193 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2194 &tun_proto); 2195 if (!tfile) 2196 return -ENOMEM; 2197 RCU_INIT_POINTER(tfile->tun, NULL); 2198 tfile->net = get_net(current->nsproxy->net_ns); 2199 tfile->flags = 0; 2200 tfile->ifindex = 0; 2201 2202 rcu_assign_pointer(tfile->socket.wq, &tfile->wq); 2203 init_waitqueue_head(&tfile->wq.wait); 2204 2205 tfile->socket.file = file; 2206 tfile->socket.ops = &tun_socket_ops; 2207 2208 sock_init_data(&tfile->socket, &tfile->sk); 2209 sk_change_net(&tfile->sk, tfile->net); 2210 2211 tfile->sk.sk_write_space = tun_sock_write_space; 2212 tfile->sk.sk_sndbuf = INT_MAX; 2213 2214 file->private_data = tfile; 2215 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2216 INIT_LIST_HEAD(&tfile->next); 2217 2218 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2219 2220 return 0; 2221 } 2222 2223 static int tun_chr_close(struct inode *inode, struct file *file) 2224 { 2225 struct tun_file *tfile = file->private_data; 2226 struct net *net = tfile->net; 2227 2228 tun_detach(tfile, true); 2229 put_net(net); 2230 2231 return 0; 2232 } 2233 2234 #ifdef CONFIG_PROC_FS 2235 static int tun_chr_show_fdinfo(struct seq_file *m, struct file *f) 2236 { 2237 struct tun_struct *tun; 2238 struct ifreq ifr; 2239 2240 memset(&ifr, 0, sizeof(ifr)); 2241 2242 rtnl_lock(); 2243 tun = tun_get(f); 2244 if (tun) 2245 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 2246 rtnl_unlock(); 2247 2248 if (tun) 2249 tun_put(tun); 2250 2251 return seq_printf(m, "iff:\t%s\n", ifr.ifr_name); 2252 } 2253 #endif 2254 2255 static const struct file_operations tun_fops = { 2256 .owner = THIS_MODULE, 2257 .llseek = no_llseek, 2258 .read = do_sync_read, 2259 .aio_read = tun_chr_aio_read, 2260 .write = do_sync_write, 2261 .aio_write = tun_chr_aio_write, 2262 .poll = tun_chr_poll, 2263 .unlocked_ioctl = tun_chr_ioctl, 2264 #ifdef CONFIG_COMPAT 2265 .compat_ioctl = tun_chr_compat_ioctl, 2266 #endif 2267 .open = tun_chr_open, 2268 .release = tun_chr_close, 2269 .fasync = tun_chr_fasync, 2270 #ifdef CONFIG_PROC_FS 2271 .show_fdinfo = tun_chr_show_fdinfo, 2272 #endif 2273 }; 2274 2275 static struct miscdevice tun_miscdev = { 2276 .minor = TUN_MINOR, 2277 .name = "tun", 2278 .nodename = "net/tun", 2279 .fops = &tun_fops, 2280 }; 2281 2282 /* ethtool interface */ 2283 2284 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2285 { 2286 cmd->supported = 0; 2287 cmd->advertising = 0; 2288 ethtool_cmd_speed_set(cmd, SPEED_10); 2289 cmd->duplex = DUPLEX_FULL; 2290 cmd->port = PORT_TP; 2291 cmd->phy_address = 0; 2292 cmd->transceiver = XCVR_INTERNAL; 2293 cmd->autoneg = AUTONEG_DISABLE; 2294 cmd->maxtxpkt = 0; 2295 cmd->maxrxpkt = 0; 2296 return 0; 2297 } 2298 2299 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2300 { 2301 struct tun_struct *tun = netdev_priv(dev); 2302 2303 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2304 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2305 2306 switch (tun->flags & TUN_TYPE_MASK) { 2307 case TUN_TUN_DEV: 2308 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2309 break; 2310 case TUN_TAP_DEV: 2311 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2312 break; 2313 } 2314 } 2315 2316 static u32 tun_get_msglevel(struct net_device *dev) 2317 { 2318 #ifdef TUN_DEBUG 2319 struct tun_struct *tun = netdev_priv(dev); 2320 return tun->debug; 2321 #else 2322 return -EOPNOTSUPP; 2323 #endif 2324 } 2325 2326 static void tun_set_msglevel(struct net_device *dev, u32 value) 2327 { 2328 #ifdef TUN_DEBUG 2329 struct tun_struct *tun = netdev_priv(dev); 2330 tun->debug = value; 2331 #endif 2332 } 2333 2334 static const struct ethtool_ops tun_ethtool_ops = { 2335 .get_settings = tun_get_settings, 2336 .get_drvinfo = tun_get_drvinfo, 2337 .get_msglevel = tun_get_msglevel, 2338 .set_msglevel = tun_set_msglevel, 2339 .get_link = ethtool_op_get_link, 2340 .get_ts_info = ethtool_op_get_ts_info, 2341 }; 2342 2343 2344 static int __init tun_init(void) 2345 { 2346 int ret = 0; 2347 2348 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2349 pr_info("%s\n", DRV_COPYRIGHT); 2350 2351 ret = rtnl_link_register(&tun_link_ops); 2352 if (ret) { 2353 pr_err("Can't register link_ops\n"); 2354 goto err_linkops; 2355 } 2356 2357 ret = misc_register(&tun_miscdev); 2358 if (ret) { 2359 pr_err("Can't register misc device %d\n", TUN_MINOR); 2360 goto err_misc; 2361 } 2362 return 0; 2363 err_misc: 2364 rtnl_link_unregister(&tun_link_ops); 2365 err_linkops: 2366 return ret; 2367 } 2368 2369 static void tun_cleanup(void) 2370 { 2371 misc_deregister(&tun_miscdev); 2372 rtnl_link_unregister(&tun_link_ops); 2373 } 2374 2375 /* Get an underlying socket object from tun file. Returns error unless file is 2376 * attached to a device. The returned object works like a packet socket, it 2377 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2378 * holding a reference to the file for as long as the socket is in use. */ 2379 struct socket *tun_get_socket(struct file *file) 2380 { 2381 struct tun_file *tfile; 2382 if (file->f_op != &tun_fops) 2383 return ERR_PTR(-EINVAL); 2384 tfile = file->private_data; 2385 if (!tfile) 2386 return ERR_PTR(-EBADFD); 2387 return &tfile->socket; 2388 } 2389 EXPORT_SYMBOL_GPL(tun_get_socket); 2390 2391 module_init(tun_init); 2392 module_exit(tun_cleanup); 2393 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2394 MODULE_AUTHOR(DRV_COPYRIGHT); 2395 MODULE_LICENSE("GPL"); 2396 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2397 MODULE_ALIAS("devname:net/tun"); 2398