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 #include <linux/uio.h> 74 75 #include <asm/uaccess.h> 76 77 /* Uncomment to enable debugging */ 78 /* #define TUN_DEBUG 1 */ 79 80 #ifdef TUN_DEBUG 81 static int debug; 82 83 #define tun_debug(level, tun, fmt, args...) \ 84 do { \ 85 if (tun->debug) \ 86 netdev_printk(level, tun->dev, fmt, ##args); \ 87 } while (0) 88 #define DBG1(level, fmt, args...) \ 89 do { \ 90 if (debug == 2) \ 91 printk(level fmt, ##args); \ 92 } while (0) 93 #else 94 #define tun_debug(level, tun, fmt, args...) \ 95 do { \ 96 if (0) \ 97 netdev_printk(level, tun->dev, fmt, ##args); \ 98 } while (0) 99 #define DBG1(level, fmt, args...) \ 100 do { \ 101 if (0) \ 102 printk(level fmt, ##args); \ 103 } while (0) 104 #endif 105 106 /* TUN device flags */ 107 108 /* IFF_ATTACH_QUEUE is never stored in device flags, 109 * overload it to mean fasync when stored there. 110 */ 111 #define TUN_FASYNC IFF_ATTACH_QUEUE 112 /* High bits in flags field are unused. */ 113 #define TUN_VNET_LE 0x80000000 114 115 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \ 116 IFF_MULTI_QUEUE) 117 #define GOODCOPY_LEN 128 118 119 #define FLT_EXACT_COUNT 8 120 struct tap_filter { 121 unsigned int count; /* Number of addrs. Zero means disabled */ 122 u32 mask[2]; /* Mask of the hashed addrs */ 123 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 124 }; 125 126 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal 127 * to max number of VCPUs in guest. */ 128 #define MAX_TAP_QUEUES 256 129 #define MAX_TAP_FLOWS 4096 130 131 #define TUN_FLOW_EXPIRE (3 * HZ) 132 133 /* A tun_file connects an open character device to a tuntap netdevice. It 134 * also contains all socket related structures (except sock_fprog and tap_filter) 135 * to serve as one transmit queue for tuntap device. The sock_fprog and 136 * tap_filter were kept in tun_struct since they were used for filtering for the 137 * netdevice not for a specific queue (at least I didn't see the requirement for 138 * this). 139 * 140 * RCU usage: 141 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 142 * other can only be read while rcu_read_lock or rtnl_lock is held. 143 */ 144 struct tun_file { 145 struct sock sk; 146 struct socket socket; 147 struct socket_wq wq; 148 struct tun_struct __rcu *tun; 149 struct fasync_struct *fasync; 150 /* only used for fasnyc */ 151 unsigned int flags; 152 union { 153 u16 queue_index; 154 unsigned int ifindex; 155 }; 156 struct list_head next; 157 struct tun_struct *detached; 158 }; 159 160 struct tun_flow_entry { 161 struct hlist_node hash_link; 162 struct rcu_head rcu; 163 struct tun_struct *tun; 164 165 u32 rxhash; 166 u32 rps_rxhash; 167 int queue_index; 168 unsigned long updated; 169 }; 170 171 #define TUN_NUM_FLOW_ENTRIES 1024 172 173 /* Since the socket were moved to tun_file, to preserve the behavior of persist 174 * device, socket filter, sndbuf and vnet header size were restore when the 175 * file were attached to a persist device. 176 */ 177 struct tun_struct { 178 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 179 unsigned int numqueues; 180 unsigned int flags; 181 kuid_t owner; 182 kgid_t group; 183 184 struct net_device *dev; 185 netdev_features_t set_features; 186 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 187 NETIF_F_TSO6|NETIF_F_UFO) 188 189 int vnet_hdr_sz; 190 int sndbuf; 191 struct tap_filter txflt; 192 struct sock_fprog fprog; 193 /* protected by rtnl lock */ 194 bool filter_attached; 195 #ifdef TUN_DEBUG 196 int debug; 197 #endif 198 spinlock_t lock; 199 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 200 struct timer_list flow_gc_timer; 201 unsigned long ageing_time; 202 unsigned int numdisabled; 203 struct list_head disabled; 204 void *security; 205 u32 flow_count; 206 }; 207 208 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) 209 { 210 return __virtio16_to_cpu(tun->flags & TUN_VNET_LE, val); 211 } 212 213 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val) 214 { 215 return __cpu_to_virtio16(tun->flags & TUN_VNET_LE, val); 216 } 217 218 static inline u32 tun_hashfn(u32 rxhash) 219 { 220 return rxhash & 0x3ff; 221 } 222 223 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 224 { 225 struct tun_flow_entry *e; 226 227 hlist_for_each_entry_rcu(e, head, hash_link) { 228 if (e->rxhash == rxhash) 229 return e; 230 } 231 return NULL; 232 } 233 234 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 235 struct hlist_head *head, 236 u32 rxhash, u16 queue_index) 237 { 238 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 239 240 if (e) { 241 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 242 rxhash, queue_index); 243 e->updated = jiffies; 244 e->rxhash = rxhash; 245 e->rps_rxhash = 0; 246 e->queue_index = queue_index; 247 e->tun = tun; 248 hlist_add_head_rcu(&e->hash_link, head); 249 ++tun->flow_count; 250 } 251 return e; 252 } 253 254 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 255 { 256 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 257 e->rxhash, e->queue_index); 258 hlist_del_rcu(&e->hash_link); 259 kfree_rcu(e, rcu); 260 --tun->flow_count; 261 } 262 263 static void tun_flow_flush(struct tun_struct *tun) 264 { 265 int i; 266 267 spin_lock_bh(&tun->lock); 268 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 269 struct tun_flow_entry *e; 270 struct hlist_node *n; 271 272 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 273 tun_flow_delete(tun, e); 274 } 275 spin_unlock_bh(&tun->lock); 276 } 277 278 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 279 { 280 int i; 281 282 spin_lock_bh(&tun->lock); 283 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 284 struct tun_flow_entry *e; 285 struct hlist_node *n; 286 287 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 288 if (e->queue_index == queue_index) 289 tun_flow_delete(tun, e); 290 } 291 } 292 spin_unlock_bh(&tun->lock); 293 } 294 295 static void tun_flow_cleanup(unsigned long data) 296 { 297 struct tun_struct *tun = (struct tun_struct *)data; 298 unsigned long delay = tun->ageing_time; 299 unsigned long next_timer = jiffies + delay; 300 unsigned long count = 0; 301 int i; 302 303 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 304 305 spin_lock_bh(&tun->lock); 306 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 307 struct tun_flow_entry *e; 308 struct hlist_node *n; 309 310 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 311 unsigned long this_timer; 312 count++; 313 this_timer = e->updated + delay; 314 if (time_before_eq(this_timer, jiffies)) 315 tun_flow_delete(tun, e); 316 else if (time_before(this_timer, next_timer)) 317 next_timer = this_timer; 318 } 319 } 320 321 if (count) 322 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 323 spin_unlock_bh(&tun->lock); 324 } 325 326 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 327 struct tun_file *tfile) 328 { 329 struct hlist_head *head; 330 struct tun_flow_entry *e; 331 unsigned long delay = tun->ageing_time; 332 u16 queue_index = tfile->queue_index; 333 334 if (!rxhash) 335 return; 336 else 337 head = &tun->flows[tun_hashfn(rxhash)]; 338 339 rcu_read_lock(); 340 341 /* We may get a very small possibility of OOO during switching, not 342 * worth to optimize.*/ 343 if (tun->numqueues == 1 || tfile->detached) 344 goto unlock; 345 346 e = tun_flow_find(head, rxhash); 347 if (likely(e)) { 348 /* TODO: keep queueing to old queue until it's empty? */ 349 e->queue_index = queue_index; 350 e->updated = jiffies; 351 sock_rps_record_flow_hash(e->rps_rxhash); 352 } else { 353 spin_lock_bh(&tun->lock); 354 if (!tun_flow_find(head, rxhash) && 355 tun->flow_count < MAX_TAP_FLOWS) 356 tun_flow_create(tun, head, rxhash, queue_index); 357 358 if (!timer_pending(&tun->flow_gc_timer)) 359 mod_timer(&tun->flow_gc_timer, 360 round_jiffies_up(jiffies + delay)); 361 spin_unlock_bh(&tun->lock); 362 } 363 364 unlock: 365 rcu_read_unlock(); 366 } 367 368 /** 369 * Save the hash received in the stack receive path and update the 370 * flow_hash table accordingly. 371 */ 372 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 373 { 374 if (unlikely(e->rps_rxhash != hash)) 375 e->rps_rxhash = hash; 376 } 377 378 /* We try to identify a flow through its rxhash first. The reason that 379 * we do not check rxq no. is because some cards(e.g 82599), chooses 380 * the rxq based on the txq where the last packet of the flow comes. As 381 * the userspace application move between processors, we may get a 382 * different rxq no. here. If we could not get rxhash, then we would 383 * hope the rxq no. may help here. 384 */ 385 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, 386 void *accel_priv, select_queue_fallback_t fallback) 387 { 388 struct tun_struct *tun = netdev_priv(dev); 389 struct tun_flow_entry *e; 390 u32 txq = 0; 391 u32 numqueues = 0; 392 393 rcu_read_lock(); 394 numqueues = ACCESS_ONCE(tun->numqueues); 395 396 txq = skb_get_hash(skb); 397 if (txq) { 398 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 399 if (e) { 400 tun_flow_save_rps_rxhash(e, txq); 401 txq = e->queue_index; 402 } else 403 /* use multiply and shift instead of expensive divide */ 404 txq = ((u64)txq * numqueues) >> 32; 405 } else if (likely(skb_rx_queue_recorded(skb))) { 406 txq = skb_get_rx_queue(skb); 407 while (unlikely(txq >= numqueues)) 408 txq -= numqueues; 409 } 410 411 rcu_read_unlock(); 412 return txq; 413 } 414 415 static inline bool tun_not_capable(struct tun_struct *tun) 416 { 417 const struct cred *cred = current_cred(); 418 struct net *net = dev_net(tun->dev); 419 420 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 421 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 422 !ns_capable(net->user_ns, CAP_NET_ADMIN); 423 } 424 425 static void tun_set_real_num_queues(struct tun_struct *tun) 426 { 427 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 428 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 429 } 430 431 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 432 { 433 tfile->detached = tun; 434 list_add_tail(&tfile->next, &tun->disabled); 435 ++tun->numdisabled; 436 } 437 438 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 439 { 440 struct tun_struct *tun = tfile->detached; 441 442 tfile->detached = NULL; 443 list_del_init(&tfile->next); 444 --tun->numdisabled; 445 return tun; 446 } 447 448 static void tun_queue_purge(struct tun_file *tfile) 449 { 450 skb_queue_purge(&tfile->sk.sk_receive_queue); 451 skb_queue_purge(&tfile->sk.sk_error_queue); 452 } 453 454 static void __tun_detach(struct tun_file *tfile, bool clean) 455 { 456 struct tun_file *ntfile; 457 struct tun_struct *tun; 458 459 tun = rtnl_dereference(tfile->tun); 460 461 if (tun && !tfile->detached) { 462 u16 index = tfile->queue_index; 463 BUG_ON(index >= tun->numqueues); 464 465 rcu_assign_pointer(tun->tfiles[index], 466 tun->tfiles[tun->numqueues - 1]); 467 ntfile = rtnl_dereference(tun->tfiles[index]); 468 ntfile->queue_index = index; 469 470 --tun->numqueues; 471 if (clean) { 472 RCU_INIT_POINTER(tfile->tun, NULL); 473 sock_put(&tfile->sk); 474 } else 475 tun_disable_queue(tun, tfile); 476 477 synchronize_net(); 478 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 479 /* Drop read queue */ 480 tun_queue_purge(tfile); 481 tun_set_real_num_queues(tun); 482 } else if (tfile->detached && clean) { 483 tun = tun_enable_queue(tfile); 484 sock_put(&tfile->sk); 485 } 486 487 if (clean) { 488 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 489 netif_carrier_off(tun->dev); 490 491 if (!(tun->flags & IFF_PERSIST) && 492 tun->dev->reg_state == NETREG_REGISTERED) 493 unregister_netdevice(tun->dev); 494 } 495 sock_put(&tfile->sk); 496 } 497 } 498 499 static void tun_detach(struct tun_file *tfile, bool clean) 500 { 501 rtnl_lock(); 502 __tun_detach(tfile, clean); 503 rtnl_unlock(); 504 } 505 506 static void tun_detach_all(struct net_device *dev) 507 { 508 struct tun_struct *tun = netdev_priv(dev); 509 struct tun_file *tfile, *tmp; 510 int i, n = tun->numqueues; 511 512 for (i = 0; i < n; i++) { 513 tfile = rtnl_dereference(tun->tfiles[i]); 514 BUG_ON(!tfile); 515 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 516 RCU_INIT_POINTER(tfile->tun, NULL); 517 --tun->numqueues; 518 } 519 list_for_each_entry(tfile, &tun->disabled, next) { 520 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 521 RCU_INIT_POINTER(tfile->tun, NULL); 522 } 523 BUG_ON(tun->numqueues != 0); 524 525 synchronize_net(); 526 for (i = 0; i < n; i++) { 527 tfile = rtnl_dereference(tun->tfiles[i]); 528 /* Drop read queue */ 529 tun_queue_purge(tfile); 530 sock_put(&tfile->sk); 531 } 532 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 533 tun_enable_queue(tfile); 534 tun_queue_purge(tfile); 535 sock_put(&tfile->sk); 536 } 537 BUG_ON(tun->numdisabled != 0); 538 539 if (tun->flags & IFF_PERSIST) 540 module_put(THIS_MODULE); 541 } 542 543 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) 544 { 545 struct tun_file *tfile = file->private_data; 546 int err; 547 548 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 549 if (err < 0) 550 goto out; 551 552 err = -EINVAL; 553 if (rtnl_dereference(tfile->tun) && !tfile->detached) 554 goto out; 555 556 err = -EBUSY; 557 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1) 558 goto out; 559 560 err = -E2BIG; 561 if (!tfile->detached && 562 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 563 goto out; 564 565 err = 0; 566 567 /* Re-attach the filter to persist device */ 568 if (!skip_filter && (tun->filter_attached == true)) { 569 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 570 if (!err) 571 goto out; 572 } 573 tfile->queue_index = tun->numqueues; 574 rcu_assign_pointer(tfile->tun, tun); 575 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 576 tun->numqueues++; 577 578 if (tfile->detached) 579 tun_enable_queue(tfile); 580 else 581 sock_hold(&tfile->sk); 582 583 tun_set_real_num_queues(tun); 584 585 /* device is allowed to go away first, so no need to hold extra 586 * refcnt. 587 */ 588 589 out: 590 return err; 591 } 592 593 static struct tun_struct *__tun_get(struct tun_file *tfile) 594 { 595 struct tun_struct *tun; 596 597 rcu_read_lock(); 598 tun = rcu_dereference(tfile->tun); 599 if (tun) 600 dev_hold(tun->dev); 601 rcu_read_unlock(); 602 603 return tun; 604 } 605 606 static struct tun_struct *tun_get(struct file *file) 607 { 608 return __tun_get(file->private_data); 609 } 610 611 static void tun_put(struct tun_struct *tun) 612 { 613 dev_put(tun->dev); 614 } 615 616 /* TAP filtering */ 617 static void addr_hash_set(u32 *mask, const u8 *addr) 618 { 619 int n = ether_crc(ETH_ALEN, addr) >> 26; 620 mask[n >> 5] |= (1 << (n & 31)); 621 } 622 623 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 624 { 625 int n = ether_crc(ETH_ALEN, addr) >> 26; 626 return mask[n >> 5] & (1 << (n & 31)); 627 } 628 629 static int update_filter(struct tap_filter *filter, void __user *arg) 630 { 631 struct { u8 u[ETH_ALEN]; } *addr; 632 struct tun_filter uf; 633 int err, alen, n, nexact; 634 635 if (copy_from_user(&uf, arg, sizeof(uf))) 636 return -EFAULT; 637 638 if (!uf.count) { 639 /* Disabled */ 640 filter->count = 0; 641 return 0; 642 } 643 644 alen = ETH_ALEN * uf.count; 645 addr = kmalloc(alen, GFP_KERNEL); 646 if (!addr) 647 return -ENOMEM; 648 649 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 650 err = -EFAULT; 651 goto done; 652 } 653 654 /* The filter is updated without holding any locks. Which is 655 * perfectly safe. We disable it first and in the worst 656 * case we'll accept a few undesired packets. */ 657 filter->count = 0; 658 wmb(); 659 660 /* Use first set of addresses as an exact filter */ 661 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 662 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 663 664 nexact = n; 665 666 /* Remaining multicast addresses are hashed, 667 * unicast will leave the filter disabled. */ 668 memset(filter->mask, 0, sizeof(filter->mask)); 669 for (; n < uf.count; n++) { 670 if (!is_multicast_ether_addr(addr[n].u)) { 671 err = 0; /* no filter */ 672 goto done; 673 } 674 addr_hash_set(filter->mask, addr[n].u); 675 } 676 677 /* For ALLMULTI just set the mask to all ones. 678 * This overrides the mask populated above. */ 679 if ((uf.flags & TUN_FLT_ALLMULTI)) 680 memset(filter->mask, ~0, sizeof(filter->mask)); 681 682 /* Now enable the filter */ 683 wmb(); 684 filter->count = nexact; 685 686 /* Return the number of exact filters */ 687 err = nexact; 688 689 done: 690 kfree(addr); 691 return err; 692 } 693 694 /* Returns: 0 - drop, !=0 - accept */ 695 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 696 { 697 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 698 * at this point. */ 699 struct ethhdr *eh = (struct ethhdr *) skb->data; 700 int i; 701 702 /* Exact match */ 703 for (i = 0; i < filter->count; i++) 704 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 705 return 1; 706 707 /* Inexact match (multicast only) */ 708 if (is_multicast_ether_addr(eh->h_dest)) 709 return addr_hash_test(filter->mask, eh->h_dest); 710 711 return 0; 712 } 713 714 /* 715 * Checks whether the packet is accepted or not. 716 * Returns: 0 - drop, !=0 - accept 717 */ 718 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 719 { 720 if (!filter->count) 721 return 1; 722 723 return run_filter(filter, skb); 724 } 725 726 /* Network device part of the driver */ 727 728 static const struct ethtool_ops tun_ethtool_ops; 729 730 /* Net device detach from fd. */ 731 static void tun_net_uninit(struct net_device *dev) 732 { 733 tun_detach_all(dev); 734 } 735 736 /* Net device open. */ 737 static int tun_net_open(struct net_device *dev) 738 { 739 netif_tx_start_all_queues(dev); 740 return 0; 741 } 742 743 /* Net device close. */ 744 static int tun_net_close(struct net_device *dev) 745 { 746 netif_tx_stop_all_queues(dev); 747 return 0; 748 } 749 750 /* Net device start xmit */ 751 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 752 { 753 struct tun_struct *tun = netdev_priv(dev); 754 int txq = skb->queue_mapping; 755 struct tun_file *tfile; 756 u32 numqueues = 0; 757 758 rcu_read_lock(); 759 tfile = rcu_dereference(tun->tfiles[txq]); 760 numqueues = ACCESS_ONCE(tun->numqueues); 761 762 /* Drop packet if interface is not attached */ 763 if (txq >= numqueues) 764 goto drop; 765 766 if (numqueues == 1) { 767 /* Select queue was not called for the skbuff, so we extract the 768 * RPS hash and save it into the flow_table here. 769 */ 770 __u32 rxhash; 771 772 rxhash = skb_get_hash(skb); 773 if (rxhash) { 774 struct tun_flow_entry *e; 775 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], 776 rxhash); 777 if (e) 778 tun_flow_save_rps_rxhash(e, rxhash); 779 } 780 } 781 782 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 783 784 BUG_ON(!tfile); 785 786 /* Drop if the filter does not like it. 787 * This is a noop if the filter is disabled. 788 * Filter can be enabled only for the TAP devices. */ 789 if (!check_filter(&tun->txflt, skb)) 790 goto drop; 791 792 if (tfile->socket.sk->sk_filter && 793 sk_filter(tfile->socket.sk, skb)) 794 goto drop; 795 796 /* Limit the number of packets queued by dividing txq length with the 797 * number of queues. 798 */ 799 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues 800 >= dev->tx_queue_len) 801 goto drop; 802 803 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 804 goto drop; 805 806 if (skb->sk) { 807 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags); 808 sw_tx_timestamp(skb); 809 } 810 811 /* Orphan the skb - required as we might hang on to it 812 * for indefinite time. 813 */ 814 skb_orphan(skb); 815 816 nf_reset(skb); 817 818 /* Enqueue packet */ 819 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 820 821 /* Notify and wake up reader process */ 822 if (tfile->flags & TUN_FASYNC) 823 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 824 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 825 826 rcu_read_unlock(); 827 return NETDEV_TX_OK; 828 829 drop: 830 dev->stats.tx_dropped++; 831 skb_tx_error(skb); 832 kfree_skb(skb); 833 rcu_read_unlock(); 834 return NET_XMIT_DROP; 835 } 836 837 static void tun_net_mclist(struct net_device *dev) 838 { 839 /* 840 * This callback is supposed to deal with mc filter in 841 * _rx_ path and has nothing to do with the _tx_ path. 842 * In rx path we always accept everything userspace gives us. 843 */ 844 } 845 846 #define MIN_MTU 68 847 #define MAX_MTU 65535 848 849 static int 850 tun_net_change_mtu(struct net_device *dev, int new_mtu) 851 { 852 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 853 return -EINVAL; 854 dev->mtu = new_mtu; 855 return 0; 856 } 857 858 static netdev_features_t tun_net_fix_features(struct net_device *dev, 859 netdev_features_t features) 860 { 861 struct tun_struct *tun = netdev_priv(dev); 862 863 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 864 } 865 #ifdef CONFIG_NET_POLL_CONTROLLER 866 static void tun_poll_controller(struct net_device *dev) 867 { 868 /* 869 * Tun only receives frames when: 870 * 1) the char device endpoint gets data from user space 871 * 2) the tun socket gets a sendmsg call from user space 872 * Since both of those are synchronous operations, we are guaranteed 873 * never to have pending data when we poll for it 874 * so there is nothing to do here but return. 875 * We need this though so netpoll recognizes us as an interface that 876 * supports polling, which enables bridge devices in virt setups to 877 * still use netconsole 878 */ 879 return; 880 } 881 #endif 882 static const struct net_device_ops tun_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_select_queue = tun_select_queue, 890 #ifdef CONFIG_NET_POLL_CONTROLLER 891 .ndo_poll_controller = tun_poll_controller, 892 #endif 893 }; 894 895 static const struct net_device_ops tap_netdev_ops = { 896 .ndo_uninit = tun_net_uninit, 897 .ndo_open = tun_net_open, 898 .ndo_stop = tun_net_close, 899 .ndo_start_xmit = tun_net_xmit, 900 .ndo_change_mtu = tun_net_change_mtu, 901 .ndo_fix_features = tun_net_fix_features, 902 .ndo_set_rx_mode = tun_net_mclist, 903 .ndo_set_mac_address = eth_mac_addr, 904 .ndo_validate_addr = eth_validate_addr, 905 .ndo_select_queue = tun_select_queue, 906 #ifdef CONFIG_NET_POLL_CONTROLLER 907 .ndo_poll_controller = tun_poll_controller, 908 #endif 909 }; 910 911 static void tun_flow_init(struct tun_struct *tun) 912 { 913 int i; 914 915 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 916 INIT_HLIST_HEAD(&tun->flows[i]); 917 918 tun->ageing_time = TUN_FLOW_EXPIRE; 919 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 920 mod_timer(&tun->flow_gc_timer, 921 round_jiffies_up(jiffies + tun->ageing_time)); 922 } 923 924 static void tun_flow_uninit(struct tun_struct *tun) 925 { 926 del_timer_sync(&tun->flow_gc_timer); 927 tun_flow_flush(tun); 928 } 929 930 /* Initialize net device. */ 931 static void tun_net_init(struct net_device *dev) 932 { 933 struct tun_struct *tun = netdev_priv(dev); 934 935 switch (tun->flags & TUN_TYPE_MASK) { 936 case IFF_TUN: 937 dev->netdev_ops = &tun_netdev_ops; 938 939 /* Point-to-Point TUN Device */ 940 dev->hard_header_len = 0; 941 dev->addr_len = 0; 942 dev->mtu = 1500; 943 944 /* Zero header length */ 945 dev->type = ARPHRD_NONE; 946 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 947 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 948 break; 949 950 case IFF_TAP: 951 dev->netdev_ops = &tap_netdev_ops; 952 /* Ethernet TAP Device */ 953 ether_setup(dev); 954 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 955 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 956 957 eth_hw_addr_random(dev); 958 959 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 960 break; 961 } 962 } 963 964 /* Character device part */ 965 966 /* Poll */ 967 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 968 { 969 struct tun_file *tfile = file->private_data; 970 struct tun_struct *tun = __tun_get(tfile); 971 struct sock *sk; 972 unsigned int mask = 0; 973 974 if (!tun) 975 return POLLERR; 976 977 sk = tfile->socket.sk; 978 979 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 980 981 poll_wait(file, sk_sleep(sk), wait); 982 983 if (!skb_queue_empty(&sk->sk_receive_queue)) 984 mask |= POLLIN | POLLRDNORM; 985 986 if (sock_writeable(sk) || 987 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 988 sock_writeable(sk))) 989 mask |= POLLOUT | POLLWRNORM; 990 991 if (tun->dev->reg_state != NETREG_REGISTERED) 992 mask = POLLERR; 993 994 tun_put(tun); 995 return mask; 996 } 997 998 /* prepad is the amount to reserve at front. len is length after that. 999 * linear is a hint as to how much to copy (usually headers). */ 1000 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 1001 size_t prepad, size_t len, 1002 size_t linear, int noblock) 1003 { 1004 struct sock *sk = tfile->socket.sk; 1005 struct sk_buff *skb; 1006 int err; 1007 1008 /* Under a page? Don't bother with paged skb. */ 1009 if (prepad + len < PAGE_SIZE || !linear) 1010 linear = len; 1011 1012 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 1013 &err, 0); 1014 if (!skb) 1015 return ERR_PTR(err); 1016 1017 skb_reserve(skb, prepad); 1018 skb_put(skb, linear); 1019 skb->data_len = len - linear; 1020 skb->len += len - linear; 1021 1022 return skb; 1023 } 1024 1025 /* Get packet from user space buffer */ 1026 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1027 void *msg_control, struct iov_iter *from, 1028 int noblock) 1029 { 1030 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1031 struct sk_buff *skb; 1032 size_t total_len = iov_iter_count(from); 1033 size_t len = total_len, align = NET_SKB_PAD, linear; 1034 struct virtio_net_hdr gso = { 0 }; 1035 int good_linear; 1036 int copylen; 1037 bool zerocopy = false; 1038 int err; 1039 u32 rxhash; 1040 ssize_t n; 1041 1042 if (!(tun->flags & IFF_NO_PI)) { 1043 if (len < sizeof(pi)) 1044 return -EINVAL; 1045 len -= sizeof(pi); 1046 1047 n = copy_from_iter(&pi, sizeof(pi), from); 1048 if (n != sizeof(pi)) 1049 return -EFAULT; 1050 } 1051 1052 if (tun->flags & IFF_VNET_HDR) { 1053 if (len < tun->vnet_hdr_sz) 1054 return -EINVAL; 1055 len -= tun->vnet_hdr_sz; 1056 1057 n = copy_from_iter(&gso, sizeof(gso), from); 1058 if (n != sizeof(gso)) 1059 return -EFAULT; 1060 1061 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1062 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len)) 1063 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2); 1064 1065 if (tun16_to_cpu(tun, gso.hdr_len) > len) 1066 return -EINVAL; 1067 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso)); 1068 } 1069 1070 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) { 1071 align += NET_IP_ALIGN; 1072 if (unlikely(len < ETH_HLEN || 1073 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN))) 1074 return -EINVAL; 1075 } 1076 1077 good_linear = SKB_MAX_HEAD(align); 1078 1079 if (msg_control) { 1080 struct iov_iter i = *from; 1081 1082 /* There are 256 bytes to be copied in skb, so there is 1083 * enough room for skb expand head in case it is used. 1084 * The rest of the buffer is mapped from userspace. 1085 */ 1086 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN; 1087 if (copylen > good_linear) 1088 copylen = good_linear; 1089 linear = copylen; 1090 iov_iter_advance(&i, copylen); 1091 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS) 1092 zerocopy = true; 1093 } 1094 1095 if (!zerocopy) { 1096 copylen = len; 1097 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear) 1098 linear = good_linear; 1099 else 1100 linear = tun16_to_cpu(tun, gso.hdr_len); 1101 } 1102 1103 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1104 if (IS_ERR(skb)) { 1105 if (PTR_ERR(skb) != -EAGAIN) 1106 tun->dev->stats.rx_dropped++; 1107 return PTR_ERR(skb); 1108 } 1109 1110 if (zerocopy) 1111 err = zerocopy_sg_from_iter(skb, from); 1112 else { 1113 err = skb_copy_datagram_from_iter(skb, 0, from, len); 1114 if (!err && msg_control) { 1115 struct ubuf_info *uarg = msg_control; 1116 uarg->callback(uarg, false); 1117 } 1118 } 1119 1120 if (err) { 1121 tun->dev->stats.rx_dropped++; 1122 kfree_skb(skb); 1123 return -EFAULT; 1124 } 1125 1126 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1127 if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start), 1128 tun16_to_cpu(tun, gso.csum_offset))) { 1129 tun->dev->stats.rx_frame_errors++; 1130 kfree_skb(skb); 1131 return -EINVAL; 1132 } 1133 } 1134 1135 switch (tun->flags & TUN_TYPE_MASK) { 1136 case IFF_TUN: 1137 if (tun->flags & IFF_NO_PI) { 1138 switch (skb->data[0] & 0xf0) { 1139 case 0x40: 1140 pi.proto = htons(ETH_P_IP); 1141 break; 1142 case 0x60: 1143 pi.proto = htons(ETH_P_IPV6); 1144 break; 1145 default: 1146 tun->dev->stats.rx_dropped++; 1147 kfree_skb(skb); 1148 return -EINVAL; 1149 } 1150 } 1151 1152 skb_reset_mac_header(skb); 1153 skb->protocol = pi.proto; 1154 skb->dev = tun->dev; 1155 break; 1156 case IFF_TAP: 1157 skb->protocol = eth_type_trans(skb, tun->dev); 1158 break; 1159 } 1160 1161 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1162 pr_debug("GSO!\n"); 1163 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1164 case VIRTIO_NET_HDR_GSO_TCPV4: 1165 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1166 break; 1167 case VIRTIO_NET_HDR_GSO_TCPV6: 1168 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1169 break; 1170 case VIRTIO_NET_HDR_GSO_UDP: 1171 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1172 break; 1173 default: 1174 tun->dev->stats.rx_frame_errors++; 1175 kfree_skb(skb); 1176 return -EINVAL; 1177 } 1178 1179 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1180 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1181 1182 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size); 1183 if (skb_shinfo(skb)->gso_size == 0) { 1184 tun->dev->stats.rx_frame_errors++; 1185 kfree_skb(skb); 1186 return -EINVAL; 1187 } 1188 1189 /* Header must be checked, and gso_segs computed. */ 1190 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1191 skb_shinfo(skb)->gso_segs = 0; 1192 } 1193 1194 /* copy skb_ubuf_info for callback when skb has no error */ 1195 if (zerocopy) { 1196 skb_shinfo(skb)->destructor_arg = msg_control; 1197 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1198 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1199 } 1200 1201 skb_reset_network_header(skb); 1202 skb_probe_transport_header(skb, 0); 1203 1204 rxhash = skb_get_hash(skb); 1205 netif_rx_ni(skb); 1206 1207 tun->dev->stats.rx_packets++; 1208 tun->dev->stats.rx_bytes += len; 1209 1210 tun_flow_update(tun, rxhash, tfile); 1211 return total_len; 1212 } 1213 1214 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from) 1215 { 1216 struct file *file = iocb->ki_filp; 1217 struct tun_struct *tun = tun_get(file); 1218 struct tun_file *tfile = file->private_data; 1219 ssize_t result; 1220 1221 if (!tun) 1222 return -EBADFD; 1223 1224 result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK); 1225 1226 tun_put(tun); 1227 return result; 1228 } 1229 1230 /* Put packet to the user space buffer */ 1231 static ssize_t tun_put_user(struct tun_struct *tun, 1232 struct tun_file *tfile, 1233 struct sk_buff *skb, 1234 struct iov_iter *iter) 1235 { 1236 struct tun_pi pi = { 0, skb->protocol }; 1237 ssize_t total; 1238 int vlan_offset = 0; 1239 int vlan_hlen = 0; 1240 int vnet_hdr_sz = 0; 1241 1242 if (skb_vlan_tag_present(skb)) 1243 vlan_hlen = VLAN_HLEN; 1244 1245 if (tun->flags & IFF_VNET_HDR) 1246 vnet_hdr_sz = tun->vnet_hdr_sz; 1247 1248 total = skb->len + vlan_hlen + vnet_hdr_sz; 1249 1250 if (!(tun->flags & IFF_NO_PI)) { 1251 if (iov_iter_count(iter) < sizeof(pi)) 1252 return -EINVAL; 1253 1254 total += sizeof(pi); 1255 if (iov_iter_count(iter) < total) { 1256 /* Packet will be striped */ 1257 pi.flags |= TUN_PKT_STRIP; 1258 } 1259 1260 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi)) 1261 return -EFAULT; 1262 } 1263 1264 if (vnet_hdr_sz) { 1265 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1266 if (iov_iter_count(iter) < vnet_hdr_sz) 1267 return -EINVAL; 1268 1269 if (skb_is_gso(skb)) { 1270 struct skb_shared_info *sinfo = skb_shinfo(skb); 1271 1272 /* This is a hint as to how much should be linear. */ 1273 gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb)); 1274 gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size); 1275 if (sinfo->gso_type & SKB_GSO_TCPV4) 1276 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1277 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1278 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1279 else if (sinfo->gso_type & SKB_GSO_UDP) 1280 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1281 else { 1282 pr_err("unexpected GSO type: " 1283 "0x%x, gso_size %d, hdr_len %d\n", 1284 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size), 1285 tun16_to_cpu(tun, gso.hdr_len)); 1286 print_hex_dump(KERN_ERR, "tun: ", 1287 DUMP_PREFIX_NONE, 1288 16, 1, skb->head, 1289 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true); 1290 WARN_ON_ONCE(1); 1291 return -EINVAL; 1292 } 1293 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1294 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1295 } else 1296 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1297 1298 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1299 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1300 gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) + 1301 vlan_hlen); 1302 gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset); 1303 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1304 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1305 } /* else everything is zero */ 1306 1307 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso)) 1308 return -EFAULT; 1309 1310 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso)); 1311 } 1312 1313 if (vlan_hlen) { 1314 int ret; 1315 struct { 1316 __be16 h_vlan_proto; 1317 __be16 h_vlan_TCI; 1318 } veth; 1319 1320 veth.h_vlan_proto = skb->vlan_proto; 1321 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb)); 1322 1323 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1324 1325 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset); 1326 if (ret || !iov_iter_count(iter)) 1327 goto done; 1328 1329 ret = copy_to_iter(&veth, sizeof(veth), iter); 1330 if (ret != sizeof(veth) || !iov_iter_count(iter)) 1331 goto done; 1332 } 1333 1334 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset); 1335 1336 done: 1337 tun->dev->stats.tx_packets++; 1338 tun->dev->stats.tx_bytes += skb->len + vlan_hlen; 1339 1340 return total; 1341 } 1342 1343 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1344 struct iov_iter *to, 1345 int noblock) 1346 { 1347 struct sk_buff *skb; 1348 ssize_t ret; 1349 int peeked, err, off = 0; 1350 1351 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1352 1353 if (!iov_iter_count(to)) 1354 return 0; 1355 1356 if (tun->dev->reg_state != NETREG_REGISTERED) 1357 return -EIO; 1358 1359 /* Read frames from queue */ 1360 skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0, 1361 &peeked, &off, &err); 1362 if (!skb) 1363 return err; 1364 1365 ret = tun_put_user(tun, tfile, skb, to); 1366 if (unlikely(ret < 0)) 1367 kfree_skb(skb); 1368 else 1369 consume_skb(skb); 1370 1371 return ret; 1372 } 1373 1374 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1375 { 1376 struct file *file = iocb->ki_filp; 1377 struct tun_file *tfile = file->private_data; 1378 struct tun_struct *tun = __tun_get(tfile); 1379 ssize_t len = iov_iter_count(to), ret; 1380 1381 if (!tun) 1382 return -EBADFD; 1383 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK); 1384 ret = min_t(ssize_t, ret, len); 1385 if (ret > 0) 1386 iocb->ki_pos = ret; 1387 tun_put(tun); 1388 return ret; 1389 } 1390 1391 static void tun_free_netdev(struct net_device *dev) 1392 { 1393 struct tun_struct *tun = netdev_priv(dev); 1394 1395 BUG_ON(!(list_empty(&tun->disabled))); 1396 tun_flow_uninit(tun); 1397 security_tun_dev_free_security(tun->security); 1398 free_netdev(dev); 1399 } 1400 1401 static void tun_setup(struct net_device *dev) 1402 { 1403 struct tun_struct *tun = netdev_priv(dev); 1404 1405 tun->owner = INVALID_UID; 1406 tun->group = INVALID_GID; 1407 1408 dev->ethtool_ops = &tun_ethtool_ops; 1409 dev->destructor = tun_free_netdev; 1410 } 1411 1412 /* Trivial set of netlink ops to allow deleting tun or tap 1413 * device with netlink. 1414 */ 1415 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1416 { 1417 return -EINVAL; 1418 } 1419 1420 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1421 .kind = DRV_NAME, 1422 .priv_size = sizeof(struct tun_struct), 1423 .setup = tun_setup, 1424 .validate = tun_validate, 1425 }; 1426 1427 static void tun_sock_write_space(struct sock *sk) 1428 { 1429 struct tun_file *tfile; 1430 wait_queue_head_t *wqueue; 1431 1432 if (!sock_writeable(sk)) 1433 return; 1434 1435 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1436 return; 1437 1438 wqueue = sk_sleep(sk); 1439 if (wqueue && waitqueue_active(wqueue)) 1440 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1441 POLLWRNORM | POLLWRBAND); 1442 1443 tfile = container_of(sk, struct tun_file, sk); 1444 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1445 } 1446 1447 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) 1448 { 1449 int ret; 1450 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1451 struct tun_struct *tun = __tun_get(tfile); 1452 1453 if (!tun) 1454 return -EBADFD; 1455 1456 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter, 1457 m->msg_flags & MSG_DONTWAIT); 1458 tun_put(tun); 1459 return ret; 1460 } 1461 1462 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, 1463 int flags) 1464 { 1465 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1466 struct tun_struct *tun = __tun_get(tfile); 1467 int ret; 1468 1469 if (!tun) 1470 return -EBADFD; 1471 1472 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1473 ret = -EINVAL; 1474 goto out; 1475 } 1476 if (flags & MSG_ERRQUEUE) { 1477 ret = sock_recv_errqueue(sock->sk, m, total_len, 1478 SOL_PACKET, TUN_TX_TIMESTAMP); 1479 goto out; 1480 } 1481 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT); 1482 if (ret > (ssize_t)total_len) { 1483 m->msg_flags |= MSG_TRUNC; 1484 ret = flags & MSG_TRUNC ? ret : total_len; 1485 } 1486 out: 1487 tun_put(tun); 1488 return ret; 1489 } 1490 1491 /* Ops structure to mimic raw sockets with tun */ 1492 static const struct proto_ops tun_socket_ops = { 1493 .sendmsg = tun_sendmsg, 1494 .recvmsg = tun_recvmsg, 1495 }; 1496 1497 static struct proto tun_proto = { 1498 .name = "tun", 1499 .owner = THIS_MODULE, 1500 .obj_size = sizeof(struct tun_file), 1501 }; 1502 1503 static int tun_flags(struct tun_struct *tun) 1504 { 1505 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP); 1506 } 1507 1508 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1509 char *buf) 1510 { 1511 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1512 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1513 } 1514 1515 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1516 char *buf) 1517 { 1518 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1519 return uid_valid(tun->owner)? 1520 sprintf(buf, "%u\n", 1521 from_kuid_munged(current_user_ns(), tun->owner)): 1522 sprintf(buf, "-1\n"); 1523 } 1524 1525 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1526 char *buf) 1527 { 1528 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1529 return gid_valid(tun->group) ? 1530 sprintf(buf, "%u\n", 1531 from_kgid_munged(current_user_ns(), tun->group)): 1532 sprintf(buf, "-1\n"); 1533 } 1534 1535 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1536 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1537 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1538 1539 static struct attribute *tun_dev_attrs[] = { 1540 &dev_attr_tun_flags.attr, 1541 &dev_attr_owner.attr, 1542 &dev_attr_group.attr, 1543 NULL 1544 }; 1545 1546 static const struct attribute_group tun_attr_group = { 1547 .attrs = tun_dev_attrs 1548 }; 1549 1550 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1551 { 1552 struct tun_struct *tun; 1553 struct tun_file *tfile = file->private_data; 1554 struct net_device *dev; 1555 int err; 1556 1557 if (tfile->detached) 1558 return -EINVAL; 1559 1560 dev = __dev_get_by_name(net, ifr->ifr_name); 1561 if (dev) { 1562 if (ifr->ifr_flags & IFF_TUN_EXCL) 1563 return -EBUSY; 1564 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1565 tun = netdev_priv(dev); 1566 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1567 tun = netdev_priv(dev); 1568 else 1569 return -EINVAL; 1570 1571 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1572 !!(tun->flags & IFF_MULTI_QUEUE)) 1573 return -EINVAL; 1574 1575 if (tun_not_capable(tun)) 1576 return -EPERM; 1577 err = security_tun_dev_open(tun->security); 1578 if (err < 0) 1579 return err; 1580 1581 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1582 if (err < 0) 1583 return err; 1584 1585 if (tun->flags & IFF_MULTI_QUEUE && 1586 (tun->numqueues + tun->numdisabled > 1)) { 1587 /* One or more queue has already been attached, no need 1588 * to initialize the device again. 1589 */ 1590 return 0; 1591 } 1592 } 1593 else { 1594 char *name; 1595 unsigned long flags = 0; 1596 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1597 MAX_TAP_QUEUES : 1; 1598 1599 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1600 return -EPERM; 1601 err = security_tun_dev_create(); 1602 if (err < 0) 1603 return err; 1604 1605 /* Set dev type */ 1606 if (ifr->ifr_flags & IFF_TUN) { 1607 /* TUN device */ 1608 flags |= IFF_TUN; 1609 name = "tun%d"; 1610 } else if (ifr->ifr_flags & IFF_TAP) { 1611 /* TAP device */ 1612 flags |= IFF_TAP; 1613 name = "tap%d"; 1614 } else 1615 return -EINVAL; 1616 1617 if (*ifr->ifr_name) 1618 name = ifr->ifr_name; 1619 1620 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1621 NET_NAME_UNKNOWN, tun_setup, queues, 1622 queues); 1623 1624 if (!dev) 1625 return -ENOMEM; 1626 1627 dev_net_set(dev, net); 1628 dev->rtnl_link_ops = &tun_link_ops; 1629 dev->ifindex = tfile->ifindex; 1630 dev->sysfs_groups[0] = &tun_attr_group; 1631 1632 tun = netdev_priv(dev); 1633 tun->dev = dev; 1634 tun->flags = flags; 1635 tun->txflt.count = 0; 1636 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1637 1638 tun->filter_attached = false; 1639 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1640 1641 spin_lock_init(&tun->lock); 1642 1643 err = security_tun_dev_alloc_security(&tun->security); 1644 if (err < 0) 1645 goto err_free_dev; 1646 1647 tun_net_init(dev); 1648 tun_flow_init(tun); 1649 1650 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1651 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1652 NETIF_F_HW_VLAN_STAG_TX; 1653 dev->features = dev->hw_features; 1654 dev->vlan_features = dev->features & 1655 ~(NETIF_F_HW_VLAN_CTAG_TX | 1656 NETIF_F_HW_VLAN_STAG_TX); 1657 1658 INIT_LIST_HEAD(&tun->disabled); 1659 err = tun_attach(tun, file, false); 1660 if (err < 0) 1661 goto err_free_flow; 1662 1663 err = register_netdevice(tun->dev); 1664 if (err < 0) 1665 goto err_detach; 1666 } 1667 1668 netif_carrier_on(tun->dev); 1669 1670 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1671 1672 tun->flags = (tun->flags & ~TUN_FEATURES) | 1673 (ifr->ifr_flags & TUN_FEATURES); 1674 1675 /* Make sure persistent devices do not get stuck in 1676 * xoff state. 1677 */ 1678 if (netif_running(tun->dev)) 1679 netif_tx_wake_all_queues(tun->dev); 1680 1681 strcpy(ifr->ifr_name, tun->dev->name); 1682 return 0; 1683 1684 err_detach: 1685 tun_detach_all(dev); 1686 err_free_flow: 1687 tun_flow_uninit(tun); 1688 security_tun_dev_free_security(tun->security); 1689 err_free_dev: 1690 free_netdev(dev); 1691 return err; 1692 } 1693 1694 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1695 struct ifreq *ifr) 1696 { 1697 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1698 1699 strcpy(ifr->ifr_name, tun->dev->name); 1700 1701 ifr->ifr_flags = tun_flags(tun); 1702 1703 } 1704 1705 /* This is like a cut-down ethtool ops, except done via tun fd so no 1706 * privs required. */ 1707 static int set_offload(struct tun_struct *tun, unsigned long arg) 1708 { 1709 netdev_features_t features = 0; 1710 1711 if (arg & TUN_F_CSUM) { 1712 features |= NETIF_F_HW_CSUM; 1713 arg &= ~TUN_F_CSUM; 1714 1715 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1716 if (arg & TUN_F_TSO_ECN) { 1717 features |= NETIF_F_TSO_ECN; 1718 arg &= ~TUN_F_TSO_ECN; 1719 } 1720 if (arg & TUN_F_TSO4) 1721 features |= NETIF_F_TSO; 1722 if (arg & TUN_F_TSO6) 1723 features |= NETIF_F_TSO6; 1724 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1725 } 1726 1727 if (arg & TUN_F_UFO) { 1728 features |= NETIF_F_UFO; 1729 arg &= ~TUN_F_UFO; 1730 } 1731 } 1732 1733 /* This gives the user a way to test for new features in future by 1734 * trying to set them. */ 1735 if (arg) 1736 return -EINVAL; 1737 1738 tun->set_features = features; 1739 netdev_update_features(tun->dev); 1740 1741 return 0; 1742 } 1743 1744 static void tun_detach_filter(struct tun_struct *tun, int n) 1745 { 1746 int i; 1747 struct tun_file *tfile; 1748 1749 for (i = 0; i < n; i++) { 1750 tfile = rtnl_dereference(tun->tfiles[i]); 1751 sk_detach_filter(tfile->socket.sk); 1752 } 1753 1754 tun->filter_attached = false; 1755 } 1756 1757 static int tun_attach_filter(struct tun_struct *tun) 1758 { 1759 int i, ret = 0; 1760 struct tun_file *tfile; 1761 1762 for (i = 0; i < tun->numqueues; i++) { 1763 tfile = rtnl_dereference(tun->tfiles[i]); 1764 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1765 if (ret) { 1766 tun_detach_filter(tun, i); 1767 return ret; 1768 } 1769 } 1770 1771 tun->filter_attached = true; 1772 return ret; 1773 } 1774 1775 static void tun_set_sndbuf(struct tun_struct *tun) 1776 { 1777 struct tun_file *tfile; 1778 int i; 1779 1780 for (i = 0; i < tun->numqueues; i++) { 1781 tfile = rtnl_dereference(tun->tfiles[i]); 1782 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1783 } 1784 } 1785 1786 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1787 { 1788 struct tun_file *tfile = file->private_data; 1789 struct tun_struct *tun; 1790 int ret = 0; 1791 1792 rtnl_lock(); 1793 1794 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1795 tun = tfile->detached; 1796 if (!tun) { 1797 ret = -EINVAL; 1798 goto unlock; 1799 } 1800 ret = security_tun_dev_attach_queue(tun->security); 1801 if (ret < 0) 1802 goto unlock; 1803 ret = tun_attach(tun, file, false); 1804 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1805 tun = rtnl_dereference(tfile->tun); 1806 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached) 1807 ret = -EINVAL; 1808 else 1809 __tun_detach(tfile, false); 1810 } else 1811 ret = -EINVAL; 1812 1813 unlock: 1814 rtnl_unlock(); 1815 return ret; 1816 } 1817 1818 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1819 unsigned long arg, int ifreq_len) 1820 { 1821 struct tun_file *tfile = file->private_data; 1822 struct tun_struct *tun; 1823 void __user* argp = (void __user*)arg; 1824 struct ifreq ifr; 1825 kuid_t owner; 1826 kgid_t group; 1827 int sndbuf; 1828 int vnet_hdr_sz; 1829 unsigned int ifindex; 1830 int le; 1831 int ret; 1832 1833 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1834 if (copy_from_user(&ifr, argp, ifreq_len)) 1835 return -EFAULT; 1836 } else { 1837 memset(&ifr, 0, sizeof(ifr)); 1838 } 1839 if (cmd == TUNGETFEATURES) { 1840 /* Currently this just means: "what IFF flags are valid?". 1841 * This is needed because we never checked for invalid flags on 1842 * TUNSETIFF. 1843 */ 1844 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES, 1845 (unsigned int __user*)argp); 1846 } else if (cmd == TUNSETQUEUE) 1847 return tun_set_queue(file, &ifr); 1848 1849 ret = 0; 1850 rtnl_lock(); 1851 1852 tun = __tun_get(tfile); 1853 if (cmd == TUNSETIFF && !tun) { 1854 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1855 1856 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr); 1857 1858 if (ret) 1859 goto unlock; 1860 1861 if (copy_to_user(argp, &ifr, ifreq_len)) 1862 ret = -EFAULT; 1863 goto unlock; 1864 } 1865 if (cmd == TUNSETIFINDEX) { 1866 ret = -EPERM; 1867 if (tun) 1868 goto unlock; 1869 1870 ret = -EFAULT; 1871 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1872 goto unlock; 1873 1874 ret = 0; 1875 tfile->ifindex = ifindex; 1876 goto unlock; 1877 } 1878 1879 ret = -EBADFD; 1880 if (!tun) 1881 goto unlock; 1882 1883 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1884 1885 ret = 0; 1886 switch (cmd) { 1887 case TUNGETIFF: 1888 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1889 1890 if (tfile->detached) 1891 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1892 if (!tfile->socket.sk->sk_filter) 1893 ifr.ifr_flags |= IFF_NOFILTER; 1894 1895 if (copy_to_user(argp, &ifr, ifreq_len)) 1896 ret = -EFAULT; 1897 break; 1898 1899 case TUNSETNOCSUM: 1900 /* Disable/Enable checksum */ 1901 1902 /* [unimplemented] */ 1903 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1904 arg ? "disabled" : "enabled"); 1905 break; 1906 1907 case TUNSETPERSIST: 1908 /* Disable/Enable persist mode. Keep an extra reference to the 1909 * module to prevent the module being unprobed. 1910 */ 1911 if (arg && !(tun->flags & IFF_PERSIST)) { 1912 tun->flags |= IFF_PERSIST; 1913 __module_get(THIS_MODULE); 1914 } 1915 if (!arg && (tun->flags & IFF_PERSIST)) { 1916 tun->flags &= ~IFF_PERSIST; 1917 module_put(THIS_MODULE); 1918 } 1919 1920 tun_debug(KERN_INFO, tun, "persist %s\n", 1921 arg ? "enabled" : "disabled"); 1922 break; 1923 1924 case TUNSETOWNER: 1925 /* Set owner of the device */ 1926 owner = make_kuid(current_user_ns(), arg); 1927 if (!uid_valid(owner)) { 1928 ret = -EINVAL; 1929 break; 1930 } 1931 tun->owner = owner; 1932 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1933 from_kuid(&init_user_ns, tun->owner)); 1934 break; 1935 1936 case TUNSETGROUP: 1937 /* Set group of the device */ 1938 group = make_kgid(current_user_ns(), arg); 1939 if (!gid_valid(group)) { 1940 ret = -EINVAL; 1941 break; 1942 } 1943 tun->group = group; 1944 tun_debug(KERN_INFO, tun, "group set to %u\n", 1945 from_kgid(&init_user_ns, tun->group)); 1946 break; 1947 1948 case TUNSETLINK: 1949 /* Only allow setting the type when the interface is down */ 1950 if (tun->dev->flags & IFF_UP) { 1951 tun_debug(KERN_INFO, tun, 1952 "Linktype set failed because interface is up\n"); 1953 ret = -EBUSY; 1954 } else { 1955 tun->dev->type = (int) arg; 1956 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1957 tun->dev->type); 1958 ret = 0; 1959 } 1960 break; 1961 1962 #ifdef TUN_DEBUG 1963 case TUNSETDEBUG: 1964 tun->debug = arg; 1965 break; 1966 #endif 1967 case TUNSETOFFLOAD: 1968 ret = set_offload(tun, arg); 1969 break; 1970 1971 case TUNSETTXFILTER: 1972 /* Can be set only for TAPs */ 1973 ret = -EINVAL; 1974 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 1975 break; 1976 ret = update_filter(&tun->txflt, (void __user *)arg); 1977 break; 1978 1979 case SIOCGIFHWADDR: 1980 /* Get hw address */ 1981 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 1982 ifr.ifr_hwaddr.sa_family = tun->dev->type; 1983 if (copy_to_user(argp, &ifr, ifreq_len)) 1984 ret = -EFAULT; 1985 break; 1986 1987 case SIOCSIFHWADDR: 1988 /* Set hw address */ 1989 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 1990 ifr.ifr_hwaddr.sa_data); 1991 1992 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 1993 break; 1994 1995 case TUNGETSNDBUF: 1996 sndbuf = tfile->socket.sk->sk_sndbuf; 1997 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 1998 ret = -EFAULT; 1999 break; 2000 2001 case TUNSETSNDBUF: 2002 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2003 ret = -EFAULT; 2004 break; 2005 } 2006 2007 tun->sndbuf = sndbuf; 2008 tun_set_sndbuf(tun); 2009 break; 2010 2011 case TUNGETVNETHDRSZ: 2012 vnet_hdr_sz = tun->vnet_hdr_sz; 2013 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2014 ret = -EFAULT; 2015 break; 2016 2017 case TUNSETVNETHDRSZ: 2018 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2019 ret = -EFAULT; 2020 break; 2021 } 2022 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2023 ret = -EINVAL; 2024 break; 2025 } 2026 2027 tun->vnet_hdr_sz = vnet_hdr_sz; 2028 break; 2029 2030 case TUNGETVNETLE: 2031 le = !!(tun->flags & TUN_VNET_LE); 2032 if (put_user(le, (int __user *)argp)) 2033 ret = -EFAULT; 2034 break; 2035 2036 case TUNSETVNETLE: 2037 if (get_user(le, (int __user *)argp)) { 2038 ret = -EFAULT; 2039 break; 2040 } 2041 if (le) 2042 tun->flags |= TUN_VNET_LE; 2043 else 2044 tun->flags &= ~TUN_VNET_LE; 2045 break; 2046 2047 case TUNATTACHFILTER: 2048 /* Can be set only for TAPs */ 2049 ret = -EINVAL; 2050 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2051 break; 2052 ret = -EFAULT; 2053 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2054 break; 2055 2056 ret = tun_attach_filter(tun); 2057 break; 2058 2059 case TUNDETACHFILTER: 2060 /* Can be set only for TAPs */ 2061 ret = -EINVAL; 2062 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2063 break; 2064 ret = 0; 2065 tun_detach_filter(tun, tun->numqueues); 2066 break; 2067 2068 case TUNGETFILTER: 2069 ret = -EINVAL; 2070 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2071 break; 2072 ret = -EFAULT; 2073 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2074 break; 2075 ret = 0; 2076 break; 2077 2078 default: 2079 ret = -EINVAL; 2080 break; 2081 } 2082 2083 unlock: 2084 rtnl_unlock(); 2085 if (tun) 2086 tun_put(tun); 2087 return ret; 2088 } 2089 2090 static long tun_chr_ioctl(struct file *file, 2091 unsigned int cmd, unsigned long arg) 2092 { 2093 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2094 } 2095 2096 #ifdef CONFIG_COMPAT 2097 static long tun_chr_compat_ioctl(struct file *file, 2098 unsigned int cmd, unsigned long arg) 2099 { 2100 switch (cmd) { 2101 case TUNSETIFF: 2102 case TUNGETIFF: 2103 case TUNSETTXFILTER: 2104 case TUNGETSNDBUF: 2105 case TUNSETSNDBUF: 2106 case SIOCGIFHWADDR: 2107 case SIOCSIFHWADDR: 2108 arg = (unsigned long)compat_ptr(arg); 2109 break; 2110 default: 2111 arg = (compat_ulong_t)arg; 2112 break; 2113 } 2114 2115 /* 2116 * compat_ifreq is shorter than ifreq, so we must not access beyond 2117 * the end of that structure. All fields that are used in this 2118 * driver are compatible though, we don't need to convert the 2119 * contents. 2120 */ 2121 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2122 } 2123 #endif /* CONFIG_COMPAT */ 2124 2125 static int tun_chr_fasync(int fd, struct file *file, int on) 2126 { 2127 struct tun_file *tfile = file->private_data; 2128 int ret; 2129 2130 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2131 goto out; 2132 2133 if (on) { 2134 __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2135 tfile->flags |= TUN_FASYNC; 2136 } else 2137 tfile->flags &= ~TUN_FASYNC; 2138 ret = 0; 2139 out: 2140 return ret; 2141 } 2142 2143 static int tun_chr_open(struct inode *inode, struct file * file) 2144 { 2145 struct net *net = current->nsproxy->net_ns; 2146 struct tun_file *tfile; 2147 2148 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2149 2150 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, 2151 &tun_proto, 0); 2152 if (!tfile) 2153 return -ENOMEM; 2154 RCU_INIT_POINTER(tfile->tun, NULL); 2155 tfile->flags = 0; 2156 tfile->ifindex = 0; 2157 2158 init_waitqueue_head(&tfile->wq.wait); 2159 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq); 2160 2161 tfile->socket.file = file; 2162 tfile->socket.ops = &tun_socket_ops; 2163 2164 sock_init_data(&tfile->socket, &tfile->sk); 2165 2166 tfile->sk.sk_write_space = tun_sock_write_space; 2167 tfile->sk.sk_sndbuf = INT_MAX; 2168 2169 file->private_data = tfile; 2170 INIT_LIST_HEAD(&tfile->next); 2171 2172 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2173 2174 return 0; 2175 } 2176 2177 static int tun_chr_close(struct inode *inode, struct file *file) 2178 { 2179 struct tun_file *tfile = file->private_data; 2180 2181 tun_detach(tfile, true); 2182 2183 return 0; 2184 } 2185 2186 #ifdef CONFIG_PROC_FS 2187 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f) 2188 { 2189 struct tun_struct *tun; 2190 struct ifreq ifr; 2191 2192 memset(&ifr, 0, sizeof(ifr)); 2193 2194 rtnl_lock(); 2195 tun = tun_get(f); 2196 if (tun) 2197 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 2198 rtnl_unlock(); 2199 2200 if (tun) 2201 tun_put(tun); 2202 2203 seq_printf(m, "iff:\t%s\n", ifr.ifr_name); 2204 } 2205 #endif 2206 2207 static const struct file_operations tun_fops = { 2208 .owner = THIS_MODULE, 2209 .llseek = no_llseek, 2210 .read_iter = tun_chr_read_iter, 2211 .write_iter = tun_chr_write_iter, 2212 .poll = tun_chr_poll, 2213 .unlocked_ioctl = tun_chr_ioctl, 2214 #ifdef CONFIG_COMPAT 2215 .compat_ioctl = tun_chr_compat_ioctl, 2216 #endif 2217 .open = tun_chr_open, 2218 .release = tun_chr_close, 2219 .fasync = tun_chr_fasync, 2220 #ifdef CONFIG_PROC_FS 2221 .show_fdinfo = tun_chr_show_fdinfo, 2222 #endif 2223 }; 2224 2225 static struct miscdevice tun_miscdev = { 2226 .minor = TUN_MINOR, 2227 .name = "tun", 2228 .nodename = "net/tun", 2229 .fops = &tun_fops, 2230 }; 2231 2232 /* ethtool interface */ 2233 2234 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2235 { 2236 cmd->supported = 0; 2237 cmd->advertising = 0; 2238 ethtool_cmd_speed_set(cmd, SPEED_10); 2239 cmd->duplex = DUPLEX_FULL; 2240 cmd->port = PORT_TP; 2241 cmd->phy_address = 0; 2242 cmd->transceiver = XCVR_INTERNAL; 2243 cmd->autoneg = AUTONEG_DISABLE; 2244 cmd->maxtxpkt = 0; 2245 cmd->maxrxpkt = 0; 2246 return 0; 2247 } 2248 2249 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2250 { 2251 struct tun_struct *tun = netdev_priv(dev); 2252 2253 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2254 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2255 2256 switch (tun->flags & TUN_TYPE_MASK) { 2257 case IFF_TUN: 2258 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2259 break; 2260 case IFF_TAP: 2261 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2262 break; 2263 } 2264 } 2265 2266 static u32 tun_get_msglevel(struct net_device *dev) 2267 { 2268 #ifdef TUN_DEBUG 2269 struct tun_struct *tun = netdev_priv(dev); 2270 return tun->debug; 2271 #else 2272 return -EOPNOTSUPP; 2273 #endif 2274 } 2275 2276 static void tun_set_msglevel(struct net_device *dev, u32 value) 2277 { 2278 #ifdef TUN_DEBUG 2279 struct tun_struct *tun = netdev_priv(dev); 2280 tun->debug = value; 2281 #endif 2282 } 2283 2284 static const struct ethtool_ops tun_ethtool_ops = { 2285 .get_settings = tun_get_settings, 2286 .get_drvinfo = tun_get_drvinfo, 2287 .get_msglevel = tun_get_msglevel, 2288 .set_msglevel = tun_set_msglevel, 2289 .get_link = ethtool_op_get_link, 2290 .get_ts_info = ethtool_op_get_ts_info, 2291 }; 2292 2293 2294 static int __init tun_init(void) 2295 { 2296 int ret = 0; 2297 2298 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2299 pr_info("%s\n", DRV_COPYRIGHT); 2300 2301 ret = rtnl_link_register(&tun_link_ops); 2302 if (ret) { 2303 pr_err("Can't register link_ops\n"); 2304 goto err_linkops; 2305 } 2306 2307 ret = misc_register(&tun_miscdev); 2308 if (ret) { 2309 pr_err("Can't register misc device %d\n", TUN_MINOR); 2310 goto err_misc; 2311 } 2312 return 0; 2313 err_misc: 2314 rtnl_link_unregister(&tun_link_ops); 2315 err_linkops: 2316 return ret; 2317 } 2318 2319 static void tun_cleanup(void) 2320 { 2321 misc_deregister(&tun_miscdev); 2322 rtnl_link_unregister(&tun_link_ops); 2323 } 2324 2325 /* Get an underlying socket object from tun file. Returns error unless file is 2326 * attached to a device. The returned object works like a packet socket, it 2327 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2328 * holding a reference to the file for as long as the socket is in use. */ 2329 struct socket *tun_get_socket(struct file *file) 2330 { 2331 struct tun_file *tfile; 2332 if (file->f_op != &tun_fops) 2333 return ERR_PTR(-EINVAL); 2334 tfile = file->private_data; 2335 if (!tfile) 2336 return ERR_PTR(-EBADFD); 2337 return &tfile->socket; 2338 } 2339 EXPORT_SYMBOL_GPL(tun_get_socket); 2340 2341 module_init(tun_init); 2342 module_exit(tun_cleanup); 2343 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2344 MODULE_AUTHOR(DRV_COPYRIGHT); 2345 MODULE_LICENSE("GPL"); 2346 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2347 MODULE_ALIAS("devname:net/tun"); 2348