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 net *net; 150 struct fasync_struct *fasync; 151 /* only used for fasnyc */ 152 unsigned int flags; 153 union { 154 u16 queue_index; 155 unsigned int ifindex; 156 }; 157 struct list_head next; 158 struct tun_struct *detached; 159 }; 160 161 struct tun_flow_entry { 162 struct hlist_node hash_link; 163 struct rcu_head rcu; 164 struct tun_struct *tun; 165 166 u32 rxhash; 167 u32 rps_rxhash; 168 int queue_index; 169 unsigned long updated; 170 }; 171 172 #define TUN_NUM_FLOW_ENTRIES 1024 173 174 /* Since the socket were moved to tun_file, to preserve the behavior of persist 175 * device, socket filter, sndbuf and vnet header size were restore when the 176 * file were attached to a persist device. 177 */ 178 struct tun_struct { 179 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 180 unsigned int numqueues; 181 unsigned int flags; 182 kuid_t owner; 183 kgid_t group; 184 185 struct net_device *dev; 186 netdev_features_t set_features; 187 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 188 NETIF_F_TSO6|NETIF_F_UFO) 189 190 int vnet_hdr_sz; 191 int sndbuf; 192 struct tap_filter txflt; 193 struct sock_fprog fprog; 194 /* protected by rtnl lock */ 195 bool filter_attached; 196 #ifdef TUN_DEBUG 197 int debug; 198 #endif 199 spinlock_t lock; 200 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 201 struct timer_list flow_gc_timer; 202 unsigned long ageing_time; 203 unsigned int numdisabled; 204 struct list_head disabled; 205 void *security; 206 u32 flow_count; 207 }; 208 209 static inline bool tun_is_little_endian(struct tun_struct *tun) 210 { 211 return tun->flags & TUN_VNET_LE || 212 virtio_legacy_is_little_endian(); 213 } 214 215 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) 216 { 217 return __virtio16_to_cpu(tun_is_little_endian(tun), val); 218 } 219 220 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val) 221 { 222 return __cpu_to_virtio16(tun_is_little_endian(tun), val); 223 } 224 225 static inline u32 tun_hashfn(u32 rxhash) 226 { 227 return rxhash & 0x3ff; 228 } 229 230 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 231 { 232 struct tun_flow_entry *e; 233 234 hlist_for_each_entry_rcu(e, head, hash_link) { 235 if (e->rxhash == rxhash) 236 return e; 237 } 238 return NULL; 239 } 240 241 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 242 struct hlist_head *head, 243 u32 rxhash, u16 queue_index) 244 { 245 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 246 247 if (e) { 248 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 249 rxhash, queue_index); 250 e->updated = jiffies; 251 e->rxhash = rxhash; 252 e->rps_rxhash = 0; 253 e->queue_index = queue_index; 254 e->tun = tun; 255 hlist_add_head_rcu(&e->hash_link, head); 256 ++tun->flow_count; 257 } 258 return e; 259 } 260 261 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 262 { 263 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 264 e->rxhash, e->queue_index); 265 hlist_del_rcu(&e->hash_link); 266 kfree_rcu(e, rcu); 267 --tun->flow_count; 268 } 269 270 static void tun_flow_flush(struct tun_struct *tun) 271 { 272 int i; 273 274 spin_lock_bh(&tun->lock); 275 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 276 struct tun_flow_entry *e; 277 struct hlist_node *n; 278 279 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 280 tun_flow_delete(tun, e); 281 } 282 spin_unlock_bh(&tun->lock); 283 } 284 285 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 286 { 287 int i; 288 289 spin_lock_bh(&tun->lock); 290 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 291 struct tun_flow_entry *e; 292 struct hlist_node *n; 293 294 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 295 if (e->queue_index == queue_index) 296 tun_flow_delete(tun, e); 297 } 298 } 299 spin_unlock_bh(&tun->lock); 300 } 301 302 static void tun_flow_cleanup(unsigned long data) 303 { 304 struct tun_struct *tun = (struct tun_struct *)data; 305 unsigned long delay = tun->ageing_time; 306 unsigned long next_timer = jiffies + delay; 307 unsigned long count = 0; 308 int i; 309 310 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 311 312 spin_lock_bh(&tun->lock); 313 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 314 struct tun_flow_entry *e; 315 struct hlist_node *n; 316 317 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 318 unsigned long this_timer; 319 count++; 320 this_timer = e->updated + delay; 321 if (time_before_eq(this_timer, jiffies)) 322 tun_flow_delete(tun, e); 323 else if (time_before(this_timer, next_timer)) 324 next_timer = this_timer; 325 } 326 } 327 328 if (count) 329 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 330 spin_unlock_bh(&tun->lock); 331 } 332 333 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 334 struct tun_file *tfile) 335 { 336 struct hlist_head *head; 337 struct tun_flow_entry *e; 338 unsigned long delay = tun->ageing_time; 339 u16 queue_index = tfile->queue_index; 340 341 if (!rxhash) 342 return; 343 else 344 head = &tun->flows[tun_hashfn(rxhash)]; 345 346 rcu_read_lock(); 347 348 /* We may get a very small possibility of OOO during switching, not 349 * worth to optimize.*/ 350 if (tun->numqueues == 1 || tfile->detached) 351 goto unlock; 352 353 e = tun_flow_find(head, rxhash); 354 if (likely(e)) { 355 /* TODO: keep queueing to old queue until it's empty? */ 356 e->queue_index = queue_index; 357 e->updated = jiffies; 358 sock_rps_record_flow_hash(e->rps_rxhash); 359 } else { 360 spin_lock_bh(&tun->lock); 361 if (!tun_flow_find(head, rxhash) && 362 tun->flow_count < MAX_TAP_FLOWS) 363 tun_flow_create(tun, head, rxhash, queue_index); 364 365 if (!timer_pending(&tun->flow_gc_timer)) 366 mod_timer(&tun->flow_gc_timer, 367 round_jiffies_up(jiffies + delay)); 368 spin_unlock_bh(&tun->lock); 369 } 370 371 unlock: 372 rcu_read_unlock(); 373 } 374 375 /** 376 * Save the hash received in the stack receive path and update the 377 * flow_hash table accordingly. 378 */ 379 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 380 { 381 if (unlikely(e->rps_rxhash != hash)) 382 e->rps_rxhash = hash; 383 } 384 385 /* We try to identify a flow through its rxhash first. The reason that 386 * we do not check rxq no. is because some cards(e.g 82599), chooses 387 * the rxq based on the txq where the last packet of the flow comes. As 388 * the userspace application move between processors, we may get a 389 * different rxq no. here. If we could not get rxhash, then we would 390 * hope the rxq no. may help here. 391 */ 392 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, 393 void *accel_priv, select_queue_fallback_t fallback) 394 { 395 struct tun_struct *tun = netdev_priv(dev); 396 struct tun_flow_entry *e; 397 u32 txq = 0; 398 u32 numqueues = 0; 399 400 rcu_read_lock(); 401 numqueues = ACCESS_ONCE(tun->numqueues); 402 403 txq = skb_get_hash(skb); 404 if (txq) { 405 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 406 if (e) { 407 tun_flow_save_rps_rxhash(e, txq); 408 txq = e->queue_index; 409 } else 410 /* use multiply and shift instead of expensive divide */ 411 txq = ((u64)txq * numqueues) >> 32; 412 } else if (likely(skb_rx_queue_recorded(skb))) { 413 txq = skb_get_rx_queue(skb); 414 while (unlikely(txq >= numqueues)) 415 txq -= numqueues; 416 } 417 418 rcu_read_unlock(); 419 return txq; 420 } 421 422 static inline bool tun_not_capable(struct tun_struct *tun) 423 { 424 const struct cred *cred = current_cred(); 425 struct net *net = dev_net(tun->dev); 426 427 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 428 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 429 !ns_capable(net->user_ns, CAP_NET_ADMIN); 430 } 431 432 static void tun_set_real_num_queues(struct tun_struct *tun) 433 { 434 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 435 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 436 } 437 438 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 439 { 440 tfile->detached = tun; 441 list_add_tail(&tfile->next, &tun->disabled); 442 ++tun->numdisabled; 443 } 444 445 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 446 { 447 struct tun_struct *tun = tfile->detached; 448 449 tfile->detached = NULL; 450 list_del_init(&tfile->next); 451 --tun->numdisabled; 452 return tun; 453 } 454 455 static void tun_queue_purge(struct tun_file *tfile) 456 { 457 skb_queue_purge(&tfile->sk.sk_receive_queue); 458 skb_queue_purge(&tfile->sk.sk_error_queue); 459 } 460 461 static void __tun_detach(struct tun_file *tfile, bool clean) 462 { 463 struct tun_file *ntfile; 464 struct tun_struct *tun; 465 466 tun = rtnl_dereference(tfile->tun); 467 468 if (tun && !tfile->detached) { 469 u16 index = tfile->queue_index; 470 BUG_ON(index >= tun->numqueues); 471 472 rcu_assign_pointer(tun->tfiles[index], 473 tun->tfiles[tun->numqueues - 1]); 474 ntfile = rtnl_dereference(tun->tfiles[index]); 475 ntfile->queue_index = index; 476 477 --tun->numqueues; 478 if (clean) { 479 RCU_INIT_POINTER(tfile->tun, NULL); 480 sock_put(&tfile->sk); 481 } else 482 tun_disable_queue(tun, tfile); 483 484 synchronize_net(); 485 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 486 /* Drop read queue */ 487 tun_queue_purge(tfile); 488 tun_set_real_num_queues(tun); 489 } else if (tfile->detached && clean) { 490 tun = tun_enable_queue(tfile); 491 sock_put(&tfile->sk); 492 } 493 494 if (clean) { 495 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 496 netif_carrier_off(tun->dev); 497 498 if (!(tun->flags & IFF_PERSIST) && 499 tun->dev->reg_state == NETREG_REGISTERED) 500 unregister_netdevice(tun->dev); 501 } 502 503 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 504 &tfile->socket.flags)); 505 sk_release_kernel(&tfile->sk); 506 } 507 } 508 509 static void tun_detach(struct tun_file *tfile, bool clean) 510 { 511 rtnl_lock(); 512 __tun_detach(tfile, clean); 513 rtnl_unlock(); 514 } 515 516 static void tun_detach_all(struct net_device *dev) 517 { 518 struct tun_struct *tun = netdev_priv(dev); 519 struct tun_file *tfile, *tmp; 520 int i, n = tun->numqueues; 521 522 for (i = 0; i < n; i++) { 523 tfile = rtnl_dereference(tun->tfiles[i]); 524 BUG_ON(!tfile); 525 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 526 RCU_INIT_POINTER(tfile->tun, NULL); 527 --tun->numqueues; 528 } 529 list_for_each_entry(tfile, &tun->disabled, next) { 530 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 531 RCU_INIT_POINTER(tfile->tun, NULL); 532 } 533 BUG_ON(tun->numqueues != 0); 534 535 synchronize_net(); 536 for (i = 0; i < n; i++) { 537 tfile = rtnl_dereference(tun->tfiles[i]); 538 /* Drop read queue */ 539 tun_queue_purge(tfile); 540 sock_put(&tfile->sk); 541 } 542 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 543 tun_enable_queue(tfile); 544 tun_queue_purge(tfile); 545 sock_put(&tfile->sk); 546 } 547 BUG_ON(tun->numdisabled != 0); 548 549 if (tun->flags & IFF_PERSIST) 550 module_put(THIS_MODULE); 551 } 552 553 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) 554 { 555 struct tun_file *tfile = file->private_data; 556 int err; 557 558 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 559 if (err < 0) 560 goto out; 561 562 err = -EINVAL; 563 if (rtnl_dereference(tfile->tun) && !tfile->detached) 564 goto out; 565 566 err = -EBUSY; 567 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1) 568 goto out; 569 570 err = -E2BIG; 571 if (!tfile->detached && 572 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 573 goto out; 574 575 err = 0; 576 577 /* Re-attach the filter to persist device */ 578 if (!skip_filter && (tun->filter_attached == true)) { 579 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 580 if (!err) 581 goto out; 582 } 583 tfile->queue_index = tun->numqueues; 584 rcu_assign_pointer(tfile->tun, tun); 585 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 586 tun->numqueues++; 587 588 if (tfile->detached) 589 tun_enable_queue(tfile); 590 else 591 sock_hold(&tfile->sk); 592 593 tun_set_real_num_queues(tun); 594 595 /* device is allowed to go away first, so no need to hold extra 596 * refcnt. 597 */ 598 599 out: 600 return err; 601 } 602 603 static struct tun_struct *__tun_get(struct tun_file *tfile) 604 { 605 struct tun_struct *tun; 606 607 rcu_read_lock(); 608 tun = rcu_dereference(tfile->tun); 609 if (tun) 610 dev_hold(tun->dev); 611 rcu_read_unlock(); 612 613 return tun; 614 } 615 616 static struct tun_struct *tun_get(struct file *file) 617 { 618 return __tun_get(file->private_data); 619 } 620 621 static void tun_put(struct tun_struct *tun) 622 { 623 dev_put(tun->dev); 624 } 625 626 /* TAP filtering */ 627 static void addr_hash_set(u32 *mask, const u8 *addr) 628 { 629 int n = ether_crc(ETH_ALEN, addr) >> 26; 630 mask[n >> 5] |= (1 << (n & 31)); 631 } 632 633 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 634 { 635 int n = ether_crc(ETH_ALEN, addr) >> 26; 636 return mask[n >> 5] & (1 << (n & 31)); 637 } 638 639 static int update_filter(struct tap_filter *filter, void __user *arg) 640 { 641 struct { u8 u[ETH_ALEN]; } *addr; 642 struct tun_filter uf; 643 int err, alen, n, nexact; 644 645 if (copy_from_user(&uf, arg, sizeof(uf))) 646 return -EFAULT; 647 648 if (!uf.count) { 649 /* Disabled */ 650 filter->count = 0; 651 return 0; 652 } 653 654 alen = ETH_ALEN * uf.count; 655 addr = kmalloc(alen, GFP_KERNEL); 656 if (!addr) 657 return -ENOMEM; 658 659 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 660 err = -EFAULT; 661 goto done; 662 } 663 664 /* The filter is updated without holding any locks. Which is 665 * perfectly safe. We disable it first and in the worst 666 * case we'll accept a few undesired packets. */ 667 filter->count = 0; 668 wmb(); 669 670 /* Use first set of addresses as an exact filter */ 671 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 672 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 673 674 nexact = n; 675 676 /* Remaining multicast addresses are hashed, 677 * unicast will leave the filter disabled. */ 678 memset(filter->mask, 0, sizeof(filter->mask)); 679 for (; n < uf.count; n++) { 680 if (!is_multicast_ether_addr(addr[n].u)) { 681 err = 0; /* no filter */ 682 goto done; 683 } 684 addr_hash_set(filter->mask, addr[n].u); 685 } 686 687 /* For ALLMULTI just set the mask to all ones. 688 * This overrides the mask populated above. */ 689 if ((uf.flags & TUN_FLT_ALLMULTI)) 690 memset(filter->mask, ~0, sizeof(filter->mask)); 691 692 /* Now enable the filter */ 693 wmb(); 694 filter->count = nexact; 695 696 /* Return the number of exact filters */ 697 err = nexact; 698 699 done: 700 kfree(addr); 701 return err; 702 } 703 704 /* Returns: 0 - drop, !=0 - accept */ 705 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 706 { 707 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 708 * at this point. */ 709 struct ethhdr *eh = (struct ethhdr *) skb->data; 710 int i; 711 712 /* Exact match */ 713 for (i = 0; i < filter->count; i++) 714 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 715 return 1; 716 717 /* Inexact match (multicast only) */ 718 if (is_multicast_ether_addr(eh->h_dest)) 719 return addr_hash_test(filter->mask, eh->h_dest); 720 721 return 0; 722 } 723 724 /* 725 * Checks whether the packet is accepted or not. 726 * Returns: 0 - drop, !=0 - accept 727 */ 728 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 729 { 730 if (!filter->count) 731 return 1; 732 733 return run_filter(filter, skb); 734 } 735 736 /* Network device part of the driver */ 737 738 static const struct ethtool_ops tun_ethtool_ops; 739 740 /* Net device detach from fd. */ 741 static void tun_net_uninit(struct net_device *dev) 742 { 743 tun_detach_all(dev); 744 } 745 746 /* Net device open. */ 747 static int tun_net_open(struct net_device *dev) 748 { 749 netif_tx_start_all_queues(dev); 750 return 0; 751 } 752 753 /* Net device close. */ 754 static int tun_net_close(struct net_device *dev) 755 { 756 netif_tx_stop_all_queues(dev); 757 return 0; 758 } 759 760 /* Net device start xmit */ 761 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 762 { 763 struct tun_struct *tun = netdev_priv(dev); 764 int txq = skb->queue_mapping; 765 struct tun_file *tfile; 766 u32 numqueues = 0; 767 768 rcu_read_lock(); 769 tfile = rcu_dereference(tun->tfiles[txq]); 770 numqueues = ACCESS_ONCE(tun->numqueues); 771 772 /* Drop packet if interface is not attached */ 773 if (txq >= numqueues) 774 goto drop; 775 776 if (numqueues == 1) { 777 /* Select queue was not called for the skbuff, so we extract the 778 * RPS hash and save it into the flow_table here. 779 */ 780 __u32 rxhash; 781 782 rxhash = skb_get_hash(skb); 783 if (rxhash) { 784 struct tun_flow_entry *e; 785 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], 786 rxhash); 787 if (e) 788 tun_flow_save_rps_rxhash(e, rxhash); 789 } 790 } 791 792 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 793 794 BUG_ON(!tfile); 795 796 /* Drop if the filter does not like it. 797 * This is a noop if the filter is disabled. 798 * Filter can be enabled only for the TAP devices. */ 799 if (!check_filter(&tun->txflt, skb)) 800 goto drop; 801 802 if (tfile->socket.sk->sk_filter && 803 sk_filter(tfile->socket.sk, skb)) 804 goto drop; 805 806 /* Limit the number of packets queued by dividing txq length with the 807 * number of queues. 808 */ 809 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues 810 >= dev->tx_queue_len) 811 goto drop; 812 813 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 814 goto drop; 815 816 if (skb->sk) { 817 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags); 818 sw_tx_timestamp(skb); 819 } 820 821 /* Orphan the skb - required as we might hang on to it 822 * for indefinite time. 823 */ 824 skb_orphan(skb); 825 826 nf_reset(skb); 827 828 /* Enqueue packet */ 829 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 830 831 /* Notify and wake up reader process */ 832 if (tfile->flags & TUN_FASYNC) 833 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 834 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 835 836 rcu_read_unlock(); 837 return NETDEV_TX_OK; 838 839 drop: 840 dev->stats.tx_dropped++; 841 skb_tx_error(skb); 842 kfree_skb(skb); 843 rcu_read_unlock(); 844 return NET_XMIT_DROP; 845 } 846 847 static void tun_net_mclist(struct net_device *dev) 848 { 849 /* 850 * This callback is supposed to deal with mc filter in 851 * _rx_ path and has nothing to do with the _tx_ path. 852 * In rx path we always accept everything userspace gives us. 853 */ 854 } 855 856 #define MIN_MTU 68 857 #define MAX_MTU 65535 858 859 static int 860 tun_net_change_mtu(struct net_device *dev, int new_mtu) 861 { 862 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 863 return -EINVAL; 864 dev->mtu = new_mtu; 865 return 0; 866 } 867 868 static netdev_features_t tun_net_fix_features(struct net_device *dev, 869 netdev_features_t features) 870 { 871 struct tun_struct *tun = netdev_priv(dev); 872 873 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 874 } 875 #ifdef CONFIG_NET_POLL_CONTROLLER 876 static void tun_poll_controller(struct net_device *dev) 877 { 878 /* 879 * Tun only receives frames when: 880 * 1) the char device endpoint gets data from user space 881 * 2) the tun socket gets a sendmsg call from user space 882 * Since both of those are synchronous operations, we are guaranteed 883 * never to have pending data when we poll for it 884 * so there is nothing to do here but return. 885 * We need this though so netpoll recognizes us as an interface that 886 * supports polling, which enables bridge devices in virt setups to 887 * still use netconsole 888 */ 889 return; 890 } 891 #endif 892 static const struct net_device_ops tun_netdev_ops = { 893 .ndo_uninit = tun_net_uninit, 894 .ndo_open = tun_net_open, 895 .ndo_stop = tun_net_close, 896 .ndo_start_xmit = tun_net_xmit, 897 .ndo_change_mtu = tun_net_change_mtu, 898 .ndo_fix_features = tun_net_fix_features, 899 .ndo_select_queue = tun_select_queue, 900 #ifdef CONFIG_NET_POLL_CONTROLLER 901 .ndo_poll_controller = tun_poll_controller, 902 #endif 903 }; 904 905 static const struct net_device_ops tap_netdev_ops = { 906 .ndo_uninit = tun_net_uninit, 907 .ndo_open = tun_net_open, 908 .ndo_stop = tun_net_close, 909 .ndo_start_xmit = tun_net_xmit, 910 .ndo_change_mtu = tun_net_change_mtu, 911 .ndo_fix_features = tun_net_fix_features, 912 .ndo_set_rx_mode = tun_net_mclist, 913 .ndo_set_mac_address = eth_mac_addr, 914 .ndo_validate_addr = eth_validate_addr, 915 .ndo_select_queue = tun_select_queue, 916 #ifdef CONFIG_NET_POLL_CONTROLLER 917 .ndo_poll_controller = tun_poll_controller, 918 #endif 919 }; 920 921 static void tun_flow_init(struct tun_struct *tun) 922 { 923 int i; 924 925 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 926 INIT_HLIST_HEAD(&tun->flows[i]); 927 928 tun->ageing_time = TUN_FLOW_EXPIRE; 929 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 930 mod_timer(&tun->flow_gc_timer, 931 round_jiffies_up(jiffies + tun->ageing_time)); 932 } 933 934 static void tun_flow_uninit(struct tun_struct *tun) 935 { 936 del_timer_sync(&tun->flow_gc_timer); 937 tun_flow_flush(tun); 938 } 939 940 /* Initialize net device. */ 941 static void tun_net_init(struct net_device *dev) 942 { 943 struct tun_struct *tun = netdev_priv(dev); 944 945 switch (tun->flags & TUN_TYPE_MASK) { 946 case IFF_TUN: 947 dev->netdev_ops = &tun_netdev_ops; 948 949 /* Point-to-Point TUN Device */ 950 dev->hard_header_len = 0; 951 dev->addr_len = 0; 952 dev->mtu = 1500; 953 954 /* Zero header length */ 955 dev->type = ARPHRD_NONE; 956 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 957 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 958 break; 959 960 case IFF_TAP: 961 dev->netdev_ops = &tap_netdev_ops; 962 /* Ethernet TAP Device */ 963 ether_setup(dev); 964 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 965 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 966 967 eth_hw_addr_random(dev); 968 969 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 970 break; 971 } 972 } 973 974 /* Character device part */ 975 976 /* Poll */ 977 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 978 { 979 struct tun_file *tfile = file->private_data; 980 struct tun_struct *tun = __tun_get(tfile); 981 struct sock *sk; 982 unsigned int mask = 0; 983 984 if (!tun) 985 return POLLERR; 986 987 sk = tfile->socket.sk; 988 989 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 990 991 poll_wait(file, sk_sleep(sk), wait); 992 993 if (!skb_queue_empty(&sk->sk_receive_queue)) 994 mask |= POLLIN | POLLRDNORM; 995 996 if (sock_writeable(sk) || 997 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 998 sock_writeable(sk))) 999 mask |= POLLOUT | POLLWRNORM; 1000 1001 if (tun->dev->reg_state != NETREG_REGISTERED) 1002 mask = POLLERR; 1003 1004 tun_put(tun); 1005 return mask; 1006 } 1007 1008 /* prepad is the amount to reserve at front. len is length after that. 1009 * linear is a hint as to how much to copy (usually headers). */ 1010 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 1011 size_t prepad, size_t len, 1012 size_t linear, int noblock) 1013 { 1014 struct sock *sk = tfile->socket.sk; 1015 struct sk_buff *skb; 1016 int err; 1017 1018 /* Under a page? Don't bother with paged skb. */ 1019 if (prepad + len < PAGE_SIZE || !linear) 1020 linear = len; 1021 1022 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 1023 &err, 0); 1024 if (!skb) 1025 return ERR_PTR(err); 1026 1027 skb_reserve(skb, prepad); 1028 skb_put(skb, linear); 1029 skb->data_len = len - linear; 1030 skb->len += len - linear; 1031 1032 return skb; 1033 } 1034 1035 /* Get packet from user space buffer */ 1036 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1037 void *msg_control, struct iov_iter *from, 1038 int noblock) 1039 { 1040 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1041 struct sk_buff *skb; 1042 size_t total_len = iov_iter_count(from); 1043 size_t len = total_len, align = NET_SKB_PAD, linear; 1044 struct virtio_net_hdr gso = { 0 }; 1045 int good_linear; 1046 int copylen; 1047 bool zerocopy = false; 1048 int err; 1049 u32 rxhash; 1050 ssize_t n; 1051 1052 if (!(tun->flags & IFF_NO_PI)) { 1053 if (len < sizeof(pi)) 1054 return -EINVAL; 1055 len -= sizeof(pi); 1056 1057 n = copy_from_iter(&pi, sizeof(pi), from); 1058 if (n != sizeof(pi)) 1059 return -EFAULT; 1060 } 1061 1062 if (tun->flags & IFF_VNET_HDR) { 1063 if (len < tun->vnet_hdr_sz) 1064 return -EINVAL; 1065 len -= tun->vnet_hdr_sz; 1066 1067 n = copy_from_iter(&gso, sizeof(gso), from); 1068 if (n != sizeof(gso)) 1069 return -EFAULT; 1070 1071 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1072 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len)) 1073 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2); 1074 1075 if (tun16_to_cpu(tun, gso.hdr_len) > len) 1076 return -EINVAL; 1077 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso)); 1078 } 1079 1080 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) { 1081 align += NET_IP_ALIGN; 1082 if (unlikely(len < ETH_HLEN || 1083 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN))) 1084 return -EINVAL; 1085 } 1086 1087 good_linear = SKB_MAX_HEAD(align); 1088 1089 if (msg_control) { 1090 struct iov_iter i = *from; 1091 1092 /* There are 256 bytes to be copied in skb, so there is 1093 * enough room for skb expand head in case it is used. 1094 * The rest of the buffer is mapped from userspace. 1095 */ 1096 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN; 1097 if (copylen > good_linear) 1098 copylen = good_linear; 1099 linear = copylen; 1100 iov_iter_advance(&i, copylen); 1101 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS) 1102 zerocopy = true; 1103 } 1104 1105 if (!zerocopy) { 1106 copylen = len; 1107 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear) 1108 linear = good_linear; 1109 else 1110 linear = tun16_to_cpu(tun, gso.hdr_len); 1111 } 1112 1113 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1114 if (IS_ERR(skb)) { 1115 if (PTR_ERR(skb) != -EAGAIN) 1116 tun->dev->stats.rx_dropped++; 1117 return PTR_ERR(skb); 1118 } 1119 1120 if (zerocopy) 1121 err = zerocopy_sg_from_iter(skb, from); 1122 else { 1123 err = skb_copy_datagram_from_iter(skb, 0, from, len); 1124 if (!err && msg_control) { 1125 struct ubuf_info *uarg = msg_control; 1126 uarg->callback(uarg, false); 1127 } 1128 } 1129 1130 if (err) { 1131 tun->dev->stats.rx_dropped++; 1132 kfree_skb(skb); 1133 return -EFAULT; 1134 } 1135 1136 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1137 if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start), 1138 tun16_to_cpu(tun, gso.csum_offset))) { 1139 tun->dev->stats.rx_frame_errors++; 1140 kfree_skb(skb); 1141 return -EINVAL; 1142 } 1143 } 1144 1145 switch (tun->flags & TUN_TYPE_MASK) { 1146 case IFF_TUN: 1147 if (tun->flags & IFF_NO_PI) { 1148 switch (skb->data[0] & 0xf0) { 1149 case 0x40: 1150 pi.proto = htons(ETH_P_IP); 1151 break; 1152 case 0x60: 1153 pi.proto = htons(ETH_P_IPV6); 1154 break; 1155 default: 1156 tun->dev->stats.rx_dropped++; 1157 kfree_skb(skb); 1158 return -EINVAL; 1159 } 1160 } 1161 1162 skb_reset_mac_header(skb); 1163 skb->protocol = pi.proto; 1164 skb->dev = tun->dev; 1165 break; 1166 case IFF_TAP: 1167 skb->protocol = eth_type_trans(skb, tun->dev); 1168 break; 1169 } 1170 1171 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1172 pr_debug("GSO!\n"); 1173 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1174 case VIRTIO_NET_HDR_GSO_TCPV4: 1175 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1176 break; 1177 case VIRTIO_NET_HDR_GSO_TCPV6: 1178 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1179 break; 1180 case VIRTIO_NET_HDR_GSO_UDP: 1181 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1182 break; 1183 default: 1184 tun->dev->stats.rx_frame_errors++; 1185 kfree_skb(skb); 1186 return -EINVAL; 1187 } 1188 1189 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1190 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1191 1192 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size); 1193 if (skb_shinfo(skb)->gso_size == 0) { 1194 tun->dev->stats.rx_frame_errors++; 1195 kfree_skb(skb); 1196 return -EINVAL; 1197 } 1198 1199 /* Header must be checked, and gso_segs computed. */ 1200 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1201 skb_shinfo(skb)->gso_segs = 0; 1202 } 1203 1204 /* copy skb_ubuf_info for callback when skb has no error */ 1205 if (zerocopy) { 1206 skb_shinfo(skb)->destructor_arg = msg_control; 1207 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1208 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1209 } 1210 1211 skb_reset_network_header(skb); 1212 skb_probe_transport_header(skb, 0); 1213 1214 rxhash = skb_get_hash(skb); 1215 netif_rx_ni(skb); 1216 1217 tun->dev->stats.rx_packets++; 1218 tun->dev->stats.rx_bytes += len; 1219 1220 tun_flow_update(tun, rxhash, tfile); 1221 return total_len; 1222 } 1223 1224 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from) 1225 { 1226 struct file *file = iocb->ki_filp; 1227 struct tun_struct *tun = tun_get(file); 1228 struct tun_file *tfile = file->private_data; 1229 ssize_t result; 1230 1231 if (!tun) 1232 return -EBADFD; 1233 1234 result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK); 1235 1236 tun_put(tun); 1237 return result; 1238 } 1239 1240 /* Put packet to the user space buffer */ 1241 static ssize_t tun_put_user(struct tun_struct *tun, 1242 struct tun_file *tfile, 1243 struct sk_buff *skb, 1244 struct iov_iter *iter) 1245 { 1246 struct tun_pi pi = { 0, skb->protocol }; 1247 ssize_t total; 1248 int vlan_offset = 0; 1249 int vlan_hlen = 0; 1250 int vnet_hdr_sz = 0; 1251 1252 if (skb_vlan_tag_present(skb)) 1253 vlan_hlen = VLAN_HLEN; 1254 1255 if (tun->flags & IFF_VNET_HDR) 1256 vnet_hdr_sz = tun->vnet_hdr_sz; 1257 1258 total = skb->len + vlan_hlen + vnet_hdr_sz; 1259 1260 if (!(tun->flags & IFF_NO_PI)) { 1261 if (iov_iter_count(iter) < sizeof(pi)) 1262 return -EINVAL; 1263 1264 total += sizeof(pi); 1265 if (iov_iter_count(iter) < total) { 1266 /* Packet will be striped */ 1267 pi.flags |= TUN_PKT_STRIP; 1268 } 1269 1270 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi)) 1271 return -EFAULT; 1272 } 1273 1274 if (vnet_hdr_sz) { 1275 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1276 if (iov_iter_count(iter) < vnet_hdr_sz) 1277 return -EINVAL; 1278 1279 if (skb_is_gso(skb)) { 1280 struct skb_shared_info *sinfo = skb_shinfo(skb); 1281 1282 /* This is a hint as to how much should be linear. */ 1283 gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb)); 1284 gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size); 1285 if (sinfo->gso_type & SKB_GSO_TCPV4) 1286 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1287 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1288 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1289 else if (sinfo->gso_type & SKB_GSO_UDP) 1290 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1291 else { 1292 pr_err("unexpected GSO type: " 1293 "0x%x, gso_size %d, hdr_len %d\n", 1294 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size), 1295 tun16_to_cpu(tun, gso.hdr_len)); 1296 print_hex_dump(KERN_ERR, "tun: ", 1297 DUMP_PREFIX_NONE, 1298 16, 1, skb->head, 1299 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true); 1300 WARN_ON_ONCE(1); 1301 return -EINVAL; 1302 } 1303 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1304 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1305 } else 1306 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1307 1308 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1309 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1310 gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) + 1311 vlan_hlen); 1312 gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset); 1313 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1314 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1315 } /* else everything is zero */ 1316 1317 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso)) 1318 return -EFAULT; 1319 1320 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso)); 1321 } 1322 1323 if (vlan_hlen) { 1324 int ret; 1325 struct { 1326 __be16 h_vlan_proto; 1327 __be16 h_vlan_TCI; 1328 } veth; 1329 1330 veth.h_vlan_proto = skb->vlan_proto; 1331 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb)); 1332 1333 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1334 1335 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset); 1336 if (ret || !iov_iter_count(iter)) 1337 goto done; 1338 1339 ret = copy_to_iter(&veth, sizeof(veth), iter); 1340 if (ret != sizeof(veth) || !iov_iter_count(iter)) 1341 goto done; 1342 } 1343 1344 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset); 1345 1346 done: 1347 tun->dev->stats.tx_packets++; 1348 tun->dev->stats.tx_bytes += skb->len + vlan_hlen; 1349 1350 return total; 1351 } 1352 1353 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1354 struct iov_iter *to, 1355 int noblock) 1356 { 1357 struct sk_buff *skb; 1358 ssize_t ret; 1359 int peeked, err, off = 0; 1360 1361 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1362 1363 if (!iov_iter_count(to)) 1364 return 0; 1365 1366 if (tun->dev->reg_state != NETREG_REGISTERED) 1367 return -EIO; 1368 1369 /* Read frames from queue */ 1370 skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0, 1371 &peeked, &off, &err); 1372 if (!skb) 1373 return err; 1374 1375 ret = tun_put_user(tun, tfile, skb, to); 1376 if (unlikely(ret < 0)) 1377 kfree_skb(skb); 1378 else 1379 consume_skb(skb); 1380 1381 return ret; 1382 } 1383 1384 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1385 { 1386 struct file *file = iocb->ki_filp; 1387 struct tun_file *tfile = file->private_data; 1388 struct tun_struct *tun = __tun_get(tfile); 1389 ssize_t len = iov_iter_count(to), ret; 1390 1391 if (!tun) 1392 return -EBADFD; 1393 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK); 1394 ret = min_t(ssize_t, ret, len); 1395 if (ret > 0) 1396 iocb->ki_pos = ret; 1397 tun_put(tun); 1398 return ret; 1399 } 1400 1401 static void tun_free_netdev(struct net_device *dev) 1402 { 1403 struct tun_struct *tun = netdev_priv(dev); 1404 1405 BUG_ON(!(list_empty(&tun->disabled))); 1406 tun_flow_uninit(tun); 1407 security_tun_dev_free_security(tun->security); 1408 free_netdev(dev); 1409 } 1410 1411 static void tun_setup(struct net_device *dev) 1412 { 1413 struct tun_struct *tun = netdev_priv(dev); 1414 1415 tun->owner = INVALID_UID; 1416 tun->group = INVALID_GID; 1417 1418 dev->ethtool_ops = &tun_ethtool_ops; 1419 dev->destructor = tun_free_netdev; 1420 } 1421 1422 /* Trivial set of netlink ops to allow deleting tun or tap 1423 * device with netlink. 1424 */ 1425 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1426 { 1427 return -EINVAL; 1428 } 1429 1430 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1431 .kind = DRV_NAME, 1432 .priv_size = sizeof(struct tun_struct), 1433 .setup = tun_setup, 1434 .validate = tun_validate, 1435 }; 1436 1437 static void tun_sock_write_space(struct sock *sk) 1438 { 1439 struct tun_file *tfile; 1440 wait_queue_head_t *wqueue; 1441 1442 if (!sock_writeable(sk)) 1443 return; 1444 1445 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1446 return; 1447 1448 wqueue = sk_sleep(sk); 1449 if (wqueue && waitqueue_active(wqueue)) 1450 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1451 POLLWRNORM | POLLWRBAND); 1452 1453 tfile = container_of(sk, struct tun_file, sk); 1454 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1455 } 1456 1457 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) 1458 { 1459 int ret; 1460 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1461 struct tun_struct *tun = __tun_get(tfile); 1462 1463 if (!tun) 1464 return -EBADFD; 1465 1466 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter, 1467 m->msg_flags & MSG_DONTWAIT); 1468 tun_put(tun); 1469 return ret; 1470 } 1471 1472 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, 1473 int flags) 1474 { 1475 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1476 struct tun_struct *tun = __tun_get(tfile); 1477 int ret; 1478 1479 if (!tun) 1480 return -EBADFD; 1481 1482 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1483 ret = -EINVAL; 1484 goto out; 1485 } 1486 if (flags & MSG_ERRQUEUE) { 1487 ret = sock_recv_errqueue(sock->sk, m, total_len, 1488 SOL_PACKET, TUN_TX_TIMESTAMP); 1489 goto out; 1490 } 1491 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT); 1492 if (ret > (ssize_t)total_len) { 1493 m->msg_flags |= MSG_TRUNC; 1494 ret = flags & MSG_TRUNC ? ret : total_len; 1495 } 1496 out: 1497 tun_put(tun); 1498 return ret; 1499 } 1500 1501 static int tun_release(struct socket *sock) 1502 { 1503 if (sock->sk) 1504 sock_put(sock->sk); 1505 return 0; 1506 } 1507 1508 /* Ops structure to mimic raw sockets with tun */ 1509 static const struct proto_ops tun_socket_ops = { 1510 .sendmsg = tun_sendmsg, 1511 .recvmsg = tun_recvmsg, 1512 .release = tun_release, 1513 }; 1514 1515 static struct proto tun_proto = { 1516 .name = "tun", 1517 .owner = THIS_MODULE, 1518 .obj_size = sizeof(struct tun_file), 1519 }; 1520 1521 static int tun_flags(struct tun_struct *tun) 1522 { 1523 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP); 1524 } 1525 1526 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1527 char *buf) 1528 { 1529 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1530 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1531 } 1532 1533 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1534 char *buf) 1535 { 1536 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1537 return uid_valid(tun->owner)? 1538 sprintf(buf, "%u\n", 1539 from_kuid_munged(current_user_ns(), tun->owner)): 1540 sprintf(buf, "-1\n"); 1541 } 1542 1543 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1544 char *buf) 1545 { 1546 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1547 return gid_valid(tun->group) ? 1548 sprintf(buf, "%u\n", 1549 from_kgid_munged(current_user_ns(), tun->group)): 1550 sprintf(buf, "-1\n"); 1551 } 1552 1553 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1554 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1555 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1556 1557 static struct attribute *tun_dev_attrs[] = { 1558 &dev_attr_tun_flags.attr, 1559 &dev_attr_owner.attr, 1560 &dev_attr_group.attr, 1561 NULL 1562 }; 1563 1564 static const struct attribute_group tun_attr_group = { 1565 .attrs = tun_dev_attrs 1566 }; 1567 1568 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1569 { 1570 struct tun_struct *tun; 1571 struct tun_file *tfile = file->private_data; 1572 struct net_device *dev; 1573 int err; 1574 1575 if (tfile->detached) 1576 return -EINVAL; 1577 1578 dev = __dev_get_by_name(net, ifr->ifr_name); 1579 if (dev) { 1580 if (ifr->ifr_flags & IFF_TUN_EXCL) 1581 return -EBUSY; 1582 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1583 tun = netdev_priv(dev); 1584 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1585 tun = netdev_priv(dev); 1586 else 1587 return -EINVAL; 1588 1589 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1590 !!(tun->flags & IFF_MULTI_QUEUE)) 1591 return -EINVAL; 1592 1593 if (tun_not_capable(tun)) 1594 return -EPERM; 1595 err = security_tun_dev_open(tun->security); 1596 if (err < 0) 1597 return err; 1598 1599 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1600 if (err < 0) 1601 return err; 1602 1603 if (tun->flags & IFF_MULTI_QUEUE && 1604 (tun->numqueues + tun->numdisabled > 1)) { 1605 /* One or more queue has already been attached, no need 1606 * to initialize the device again. 1607 */ 1608 return 0; 1609 } 1610 } 1611 else { 1612 char *name; 1613 unsigned long flags = 0; 1614 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1615 MAX_TAP_QUEUES : 1; 1616 1617 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1618 return -EPERM; 1619 err = security_tun_dev_create(); 1620 if (err < 0) 1621 return err; 1622 1623 /* Set dev type */ 1624 if (ifr->ifr_flags & IFF_TUN) { 1625 /* TUN device */ 1626 flags |= IFF_TUN; 1627 name = "tun%d"; 1628 } else if (ifr->ifr_flags & IFF_TAP) { 1629 /* TAP device */ 1630 flags |= IFF_TAP; 1631 name = "tap%d"; 1632 } else 1633 return -EINVAL; 1634 1635 if (*ifr->ifr_name) 1636 name = ifr->ifr_name; 1637 1638 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1639 NET_NAME_UNKNOWN, tun_setup, queues, 1640 queues); 1641 1642 if (!dev) 1643 return -ENOMEM; 1644 1645 dev_net_set(dev, net); 1646 dev->rtnl_link_ops = &tun_link_ops; 1647 dev->ifindex = tfile->ifindex; 1648 dev->sysfs_groups[0] = &tun_attr_group; 1649 1650 tun = netdev_priv(dev); 1651 tun->dev = dev; 1652 tun->flags = flags; 1653 tun->txflt.count = 0; 1654 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1655 1656 tun->filter_attached = false; 1657 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1658 1659 spin_lock_init(&tun->lock); 1660 1661 err = security_tun_dev_alloc_security(&tun->security); 1662 if (err < 0) 1663 goto err_free_dev; 1664 1665 tun_net_init(dev); 1666 tun_flow_init(tun); 1667 1668 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1669 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1670 NETIF_F_HW_VLAN_STAG_TX; 1671 dev->features = dev->hw_features; 1672 dev->vlan_features = dev->features & 1673 ~(NETIF_F_HW_VLAN_CTAG_TX | 1674 NETIF_F_HW_VLAN_STAG_TX); 1675 1676 INIT_LIST_HEAD(&tun->disabled); 1677 err = tun_attach(tun, file, false); 1678 if (err < 0) 1679 goto err_free_flow; 1680 1681 err = register_netdevice(tun->dev); 1682 if (err < 0) 1683 goto err_detach; 1684 } 1685 1686 netif_carrier_on(tun->dev); 1687 1688 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1689 1690 tun->flags = (tun->flags & ~TUN_FEATURES) | 1691 (ifr->ifr_flags & TUN_FEATURES); 1692 1693 /* Make sure persistent devices do not get stuck in 1694 * xoff state. 1695 */ 1696 if (netif_running(tun->dev)) 1697 netif_tx_wake_all_queues(tun->dev); 1698 1699 strcpy(ifr->ifr_name, tun->dev->name); 1700 return 0; 1701 1702 err_detach: 1703 tun_detach_all(dev); 1704 err_free_flow: 1705 tun_flow_uninit(tun); 1706 security_tun_dev_free_security(tun->security); 1707 err_free_dev: 1708 free_netdev(dev); 1709 return err; 1710 } 1711 1712 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1713 struct ifreq *ifr) 1714 { 1715 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1716 1717 strcpy(ifr->ifr_name, tun->dev->name); 1718 1719 ifr->ifr_flags = tun_flags(tun); 1720 1721 } 1722 1723 /* This is like a cut-down ethtool ops, except done via tun fd so no 1724 * privs required. */ 1725 static int set_offload(struct tun_struct *tun, unsigned long arg) 1726 { 1727 netdev_features_t features = 0; 1728 1729 if (arg & TUN_F_CSUM) { 1730 features |= NETIF_F_HW_CSUM; 1731 arg &= ~TUN_F_CSUM; 1732 1733 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1734 if (arg & TUN_F_TSO_ECN) { 1735 features |= NETIF_F_TSO_ECN; 1736 arg &= ~TUN_F_TSO_ECN; 1737 } 1738 if (arg & TUN_F_TSO4) 1739 features |= NETIF_F_TSO; 1740 if (arg & TUN_F_TSO6) 1741 features |= NETIF_F_TSO6; 1742 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1743 } 1744 1745 if (arg & TUN_F_UFO) { 1746 features |= NETIF_F_UFO; 1747 arg &= ~TUN_F_UFO; 1748 } 1749 } 1750 1751 /* This gives the user a way to test for new features in future by 1752 * trying to set them. */ 1753 if (arg) 1754 return -EINVAL; 1755 1756 tun->set_features = features; 1757 netdev_update_features(tun->dev); 1758 1759 return 0; 1760 } 1761 1762 static void tun_detach_filter(struct tun_struct *tun, int n) 1763 { 1764 int i; 1765 struct tun_file *tfile; 1766 1767 for (i = 0; i < n; i++) { 1768 tfile = rtnl_dereference(tun->tfiles[i]); 1769 sk_detach_filter(tfile->socket.sk); 1770 } 1771 1772 tun->filter_attached = false; 1773 } 1774 1775 static int tun_attach_filter(struct tun_struct *tun) 1776 { 1777 int i, ret = 0; 1778 struct tun_file *tfile; 1779 1780 for (i = 0; i < tun->numqueues; i++) { 1781 tfile = rtnl_dereference(tun->tfiles[i]); 1782 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1783 if (ret) { 1784 tun_detach_filter(tun, i); 1785 return ret; 1786 } 1787 } 1788 1789 tun->filter_attached = true; 1790 return ret; 1791 } 1792 1793 static void tun_set_sndbuf(struct tun_struct *tun) 1794 { 1795 struct tun_file *tfile; 1796 int i; 1797 1798 for (i = 0; i < tun->numqueues; i++) { 1799 tfile = rtnl_dereference(tun->tfiles[i]); 1800 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1801 } 1802 } 1803 1804 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1805 { 1806 struct tun_file *tfile = file->private_data; 1807 struct tun_struct *tun; 1808 int ret = 0; 1809 1810 rtnl_lock(); 1811 1812 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1813 tun = tfile->detached; 1814 if (!tun) { 1815 ret = -EINVAL; 1816 goto unlock; 1817 } 1818 ret = security_tun_dev_attach_queue(tun->security); 1819 if (ret < 0) 1820 goto unlock; 1821 ret = tun_attach(tun, file, false); 1822 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1823 tun = rtnl_dereference(tfile->tun); 1824 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached) 1825 ret = -EINVAL; 1826 else 1827 __tun_detach(tfile, false); 1828 } else 1829 ret = -EINVAL; 1830 1831 unlock: 1832 rtnl_unlock(); 1833 return ret; 1834 } 1835 1836 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1837 unsigned long arg, int ifreq_len) 1838 { 1839 struct tun_file *tfile = file->private_data; 1840 struct tun_struct *tun; 1841 void __user* argp = (void __user*)arg; 1842 struct ifreq ifr; 1843 kuid_t owner; 1844 kgid_t group; 1845 int sndbuf; 1846 int vnet_hdr_sz; 1847 unsigned int ifindex; 1848 int le; 1849 int ret; 1850 1851 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1852 if (copy_from_user(&ifr, argp, ifreq_len)) 1853 return -EFAULT; 1854 } else { 1855 memset(&ifr, 0, sizeof(ifr)); 1856 } 1857 if (cmd == TUNGETFEATURES) { 1858 /* Currently this just means: "what IFF flags are valid?". 1859 * This is needed because we never checked for invalid flags on 1860 * TUNSETIFF. 1861 */ 1862 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES, 1863 (unsigned int __user*)argp); 1864 } else if (cmd == TUNSETQUEUE) 1865 return tun_set_queue(file, &ifr); 1866 1867 ret = 0; 1868 rtnl_lock(); 1869 1870 tun = __tun_get(tfile); 1871 if (cmd == TUNSETIFF && !tun) { 1872 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1873 1874 ret = tun_set_iff(tfile->net, file, &ifr); 1875 1876 if (ret) 1877 goto unlock; 1878 1879 if (copy_to_user(argp, &ifr, ifreq_len)) 1880 ret = -EFAULT; 1881 goto unlock; 1882 } 1883 if (cmd == TUNSETIFINDEX) { 1884 ret = -EPERM; 1885 if (tun) 1886 goto unlock; 1887 1888 ret = -EFAULT; 1889 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1890 goto unlock; 1891 1892 ret = 0; 1893 tfile->ifindex = ifindex; 1894 goto unlock; 1895 } 1896 1897 ret = -EBADFD; 1898 if (!tun) 1899 goto unlock; 1900 1901 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1902 1903 ret = 0; 1904 switch (cmd) { 1905 case TUNGETIFF: 1906 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1907 1908 if (tfile->detached) 1909 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1910 if (!tfile->socket.sk->sk_filter) 1911 ifr.ifr_flags |= IFF_NOFILTER; 1912 1913 if (copy_to_user(argp, &ifr, ifreq_len)) 1914 ret = -EFAULT; 1915 break; 1916 1917 case TUNSETNOCSUM: 1918 /* Disable/Enable checksum */ 1919 1920 /* [unimplemented] */ 1921 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1922 arg ? "disabled" : "enabled"); 1923 break; 1924 1925 case TUNSETPERSIST: 1926 /* Disable/Enable persist mode. Keep an extra reference to the 1927 * module to prevent the module being unprobed. 1928 */ 1929 if (arg && !(tun->flags & IFF_PERSIST)) { 1930 tun->flags |= IFF_PERSIST; 1931 __module_get(THIS_MODULE); 1932 } 1933 if (!arg && (tun->flags & IFF_PERSIST)) { 1934 tun->flags &= ~IFF_PERSIST; 1935 module_put(THIS_MODULE); 1936 } 1937 1938 tun_debug(KERN_INFO, tun, "persist %s\n", 1939 arg ? "enabled" : "disabled"); 1940 break; 1941 1942 case TUNSETOWNER: 1943 /* Set owner of the device */ 1944 owner = make_kuid(current_user_ns(), arg); 1945 if (!uid_valid(owner)) { 1946 ret = -EINVAL; 1947 break; 1948 } 1949 tun->owner = owner; 1950 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1951 from_kuid(&init_user_ns, tun->owner)); 1952 break; 1953 1954 case TUNSETGROUP: 1955 /* Set group of the device */ 1956 group = make_kgid(current_user_ns(), arg); 1957 if (!gid_valid(group)) { 1958 ret = -EINVAL; 1959 break; 1960 } 1961 tun->group = group; 1962 tun_debug(KERN_INFO, tun, "group set to %u\n", 1963 from_kgid(&init_user_ns, tun->group)); 1964 break; 1965 1966 case TUNSETLINK: 1967 /* Only allow setting the type when the interface is down */ 1968 if (tun->dev->flags & IFF_UP) { 1969 tun_debug(KERN_INFO, tun, 1970 "Linktype set failed because interface is up\n"); 1971 ret = -EBUSY; 1972 } else { 1973 tun->dev->type = (int) arg; 1974 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1975 tun->dev->type); 1976 ret = 0; 1977 } 1978 break; 1979 1980 #ifdef TUN_DEBUG 1981 case TUNSETDEBUG: 1982 tun->debug = arg; 1983 break; 1984 #endif 1985 case TUNSETOFFLOAD: 1986 ret = set_offload(tun, arg); 1987 break; 1988 1989 case TUNSETTXFILTER: 1990 /* Can be set only for TAPs */ 1991 ret = -EINVAL; 1992 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 1993 break; 1994 ret = update_filter(&tun->txflt, (void __user *)arg); 1995 break; 1996 1997 case SIOCGIFHWADDR: 1998 /* Get hw address */ 1999 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 2000 ifr.ifr_hwaddr.sa_family = tun->dev->type; 2001 if (copy_to_user(argp, &ifr, ifreq_len)) 2002 ret = -EFAULT; 2003 break; 2004 2005 case SIOCSIFHWADDR: 2006 /* Set hw address */ 2007 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 2008 ifr.ifr_hwaddr.sa_data); 2009 2010 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2011 break; 2012 2013 case TUNGETSNDBUF: 2014 sndbuf = tfile->socket.sk->sk_sndbuf; 2015 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2016 ret = -EFAULT; 2017 break; 2018 2019 case TUNSETSNDBUF: 2020 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2021 ret = -EFAULT; 2022 break; 2023 } 2024 2025 tun->sndbuf = sndbuf; 2026 tun_set_sndbuf(tun); 2027 break; 2028 2029 case TUNGETVNETHDRSZ: 2030 vnet_hdr_sz = tun->vnet_hdr_sz; 2031 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2032 ret = -EFAULT; 2033 break; 2034 2035 case TUNSETVNETHDRSZ: 2036 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2037 ret = -EFAULT; 2038 break; 2039 } 2040 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2041 ret = -EINVAL; 2042 break; 2043 } 2044 2045 tun->vnet_hdr_sz = vnet_hdr_sz; 2046 break; 2047 2048 case TUNGETVNETLE: 2049 le = !!(tun->flags & TUN_VNET_LE); 2050 if (put_user(le, (int __user *)argp)) 2051 ret = -EFAULT; 2052 break; 2053 2054 case TUNSETVNETLE: 2055 if (get_user(le, (int __user *)argp)) { 2056 ret = -EFAULT; 2057 break; 2058 } 2059 if (le) 2060 tun->flags |= TUN_VNET_LE; 2061 else 2062 tun->flags &= ~TUN_VNET_LE; 2063 break; 2064 2065 case TUNATTACHFILTER: 2066 /* Can be set only for TAPs */ 2067 ret = -EINVAL; 2068 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2069 break; 2070 ret = -EFAULT; 2071 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2072 break; 2073 2074 ret = tun_attach_filter(tun); 2075 break; 2076 2077 case TUNDETACHFILTER: 2078 /* Can be set only for TAPs */ 2079 ret = -EINVAL; 2080 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2081 break; 2082 ret = 0; 2083 tun_detach_filter(tun, tun->numqueues); 2084 break; 2085 2086 case TUNGETFILTER: 2087 ret = -EINVAL; 2088 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2089 break; 2090 ret = -EFAULT; 2091 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2092 break; 2093 ret = 0; 2094 break; 2095 2096 default: 2097 ret = -EINVAL; 2098 break; 2099 } 2100 2101 unlock: 2102 rtnl_unlock(); 2103 if (tun) 2104 tun_put(tun); 2105 return ret; 2106 } 2107 2108 static long tun_chr_ioctl(struct file *file, 2109 unsigned int cmd, unsigned long arg) 2110 { 2111 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2112 } 2113 2114 #ifdef CONFIG_COMPAT 2115 static long tun_chr_compat_ioctl(struct file *file, 2116 unsigned int cmd, unsigned long arg) 2117 { 2118 switch (cmd) { 2119 case TUNSETIFF: 2120 case TUNGETIFF: 2121 case TUNSETTXFILTER: 2122 case TUNGETSNDBUF: 2123 case TUNSETSNDBUF: 2124 case SIOCGIFHWADDR: 2125 case SIOCSIFHWADDR: 2126 arg = (unsigned long)compat_ptr(arg); 2127 break; 2128 default: 2129 arg = (compat_ulong_t)arg; 2130 break; 2131 } 2132 2133 /* 2134 * compat_ifreq is shorter than ifreq, so we must not access beyond 2135 * the end of that structure. All fields that are used in this 2136 * driver are compatible though, we don't need to convert the 2137 * contents. 2138 */ 2139 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2140 } 2141 #endif /* CONFIG_COMPAT */ 2142 2143 static int tun_chr_fasync(int fd, struct file *file, int on) 2144 { 2145 struct tun_file *tfile = file->private_data; 2146 int ret; 2147 2148 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2149 goto out; 2150 2151 if (on) { 2152 __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2153 tfile->flags |= TUN_FASYNC; 2154 } else 2155 tfile->flags &= ~TUN_FASYNC; 2156 ret = 0; 2157 out: 2158 return ret; 2159 } 2160 2161 static int tun_chr_open(struct inode *inode, struct file * file) 2162 { 2163 struct tun_file *tfile; 2164 2165 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2166 2167 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2168 &tun_proto); 2169 if (!tfile) 2170 return -ENOMEM; 2171 RCU_INIT_POINTER(tfile->tun, NULL); 2172 tfile->net = get_net(current->nsproxy->net_ns); 2173 tfile->flags = 0; 2174 tfile->ifindex = 0; 2175 2176 init_waitqueue_head(&tfile->wq.wait); 2177 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq); 2178 2179 tfile->socket.file = file; 2180 tfile->socket.ops = &tun_socket_ops; 2181 2182 sock_init_data(&tfile->socket, &tfile->sk); 2183 sk_change_net(&tfile->sk, tfile->net); 2184 2185 tfile->sk.sk_write_space = tun_sock_write_space; 2186 tfile->sk.sk_sndbuf = INT_MAX; 2187 2188 file->private_data = tfile; 2189 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2190 INIT_LIST_HEAD(&tfile->next); 2191 2192 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2193 2194 return 0; 2195 } 2196 2197 static int tun_chr_close(struct inode *inode, struct file *file) 2198 { 2199 struct tun_file *tfile = file->private_data; 2200 struct net *net = tfile->net; 2201 2202 tun_detach(tfile, true); 2203 put_net(net); 2204 2205 return 0; 2206 } 2207 2208 #ifdef CONFIG_PROC_FS 2209 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f) 2210 { 2211 struct tun_struct *tun; 2212 struct ifreq ifr; 2213 2214 memset(&ifr, 0, sizeof(ifr)); 2215 2216 rtnl_lock(); 2217 tun = tun_get(f); 2218 if (tun) 2219 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 2220 rtnl_unlock(); 2221 2222 if (tun) 2223 tun_put(tun); 2224 2225 seq_printf(m, "iff:\t%s\n", ifr.ifr_name); 2226 } 2227 #endif 2228 2229 static const struct file_operations tun_fops = { 2230 .owner = THIS_MODULE, 2231 .llseek = no_llseek, 2232 .read_iter = tun_chr_read_iter, 2233 .write_iter = tun_chr_write_iter, 2234 .poll = tun_chr_poll, 2235 .unlocked_ioctl = tun_chr_ioctl, 2236 #ifdef CONFIG_COMPAT 2237 .compat_ioctl = tun_chr_compat_ioctl, 2238 #endif 2239 .open = tun_chr_open, 2240 .release = tun_chr_close, 2241 .fasync = tun_chr_fasync, 2242 #ifdef CONFIG_PROC_FS 2243 .show_fdinfo = tun_chr_show_fdinfo, 2244 #endif 2245 }; 2246 2247 static struct miscdevice tun_miscdev = { 2248 .minor = TUN_MINOR, 2249 .name = "tun", 2250 .nodename = "net/tun", 2251 .fops = &tun_fops, 2252 }; 2253 2254 /* ethtool interface */ 2255 2256 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2257 { 2258 cmd->supported = 0; 2259 cmd->advertising = 0; 2260 ethtool_cmd_speed_set(cmd, SPEED_10); 2261 cmd->duplex = DUPLEX_FULL; 2262 cmd->port = PORT_TP; 2263 cmd->phy_address = 0; 2264 cmd->transceiver = XCVR_INTERNAL; 2265 cmd->autoneg = AUTONEG_DISABLE; 2266 cmd->maxtxpkt = 0; 2267 cmd->maxrxpkt = 0; 2268 return 0; 2269 } 2270 2271 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2272 { 2273 struct tun_struct *tun = netdev_priv(dev); 2274 2275 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2276 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2277 2278 switch (tun->flags & TUN_TYPE_MASK) { 2279 case IFF_TUN: 2280 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2281 break; 2282 case IFF_TAP: 2283 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2284 break; 2285 } 2286 } 2287 2288 static u32 tun_get_msglevel(struct net_device *dev) 2289 { 2290 #ifdef TUN_DEBUG 2291 struct tun_struct *tun = netdev_priv(dev); 2292 return tun->debug; 2293 #else 2294 return -EOPNOTSUPP; 2295 #endif 2296 } 2297 2298 static void tun_set_msglevel(struct net_device *dev, u32 value) 2299 { 2300 #ifdef TUN_DEBUG 2301 struct tun_struct *tun = netdev_priv(dev); 2302 tun->debug = value; 2303 #endif 2304 } 2305 2306 static const struct ethtool_ops tun_ethtool_ops = { 2307 .get_settings = tun_get_settings, 2308 .get_drvinfo = tun_get_drvinfo, 2309 .get_msglevel = tun_get_msglevel, 2310 .set_msglevel = tun_set_msglevel, 2311 .get_link = ethtool_op_get_link, 2312 .get_ts_info = ethtool_op_get_ts_info, 2313 }; 2314 2315 2316 static int __init tun_init(void) 2317 { 2318 int ret = 0; 2319 2320 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2321 pr_info("%s\n", DRV_COPYRIGHT); 2322 2323 ret = rtnl_link_register(&tun_link_ops); 2324 if (ret) { 2325 pr_err("Can't register link_ops\n"); 2326 goto err_linkops; 2327 } 2328 2329 ret = misc_register(&tun_miscdev); 2330 if (ret) { 2331 pr_err("Can't register misc device %d\n", TUN_MINOR); 2332 goto err_misc; 2333 } 2334 return 0; 2335 err_misc: 2336 rtnl_link_unregister(&tun_link_ops); 2337 err_linkops: 2338 return ret; 2339 } 2340 2341 static void tun_cleanup(void) 2342 { 2343 misc_deregister(&tun_miscdev); 2344 rtnl_link_unregister(&tun_link_ops); 2345 } 2346 2347 /* Get an underlying socket object from tun file. Returns error unless file is 2348 * attached to a device. The returned object works like a packet socket, it 2349 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2350 * holding a reference to the file for as long as the socket is in use. */ 2351 struct socket *tun_get_socket(struct file *file) 2352 { 2353 struct tun_file *tfile; 2354 if (file->f_op != &tun_fops) 2355 return ERR_PTR(-EINVAL); 2356 tfile = file->private_data; 2357 if (!tfile) 2358 return ERR_PTR(-EBADFD); 2359 return &tfile->socket; 2360 } 2361 EXPORT_SYMBOL_GPL(tun_get_socket); 2362 2363 module_init(tun_init); 2364 module_exit(tun_cleanup); 2365 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2366 MODULE_AUTHOR(DRV_COPYRIGHT); 2367 MODULE_LICENSE("GPL"); 2368 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2369 MODULE_ALIAS("devname:net/tun"); 2370