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 /* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for 127 * the netdevice to be fit in one page. So we can make sure the success of 128 * memory allocation. TODO: increase the limit. */ 129 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES 130 #define MAX_TAP_FLOWS 4096 131 132 #define TUN_FLOW_EXPIRE (3 * HZ) 133 134 /* A tun_file connects an open character device to a tuntap netdevice. It 135 * also contains all socket related structures (except sock_fprog and tap_filter) 136 * to serve as one transmit queue for tuntap device. The sock_fprog and 137 * tap_filter were kept in tun_struct since they were used for filtering for the 138 * netdevice not for a specific queue (at least I didn't see the requirement for 139 * this). 140 * 141 * RCU usage: 142 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 143 * other can only be read while rcu_read_lock or rtnl_lock is held. 144 */ 145 struct tun_file { 146 struct sock sk; 147 struct socket socket; 148 struct socket_wq wq; 149 struct tun_struct __rcu *tun; 150 struct net *net; 151 struct fasync_struct *fasync; 152 /* only used for fasnyc */ 153 unsigned int flags; 154 union { 155 u16 queue_index; 156 unsigned int ifindex; 157 }; 158 struct list_head next; 159 struct tun_struct *detached; 160 }; 161 162 struct tun_flow_entry { 163 struct hlist_node hash_link; 164 struct rcu_head rcu; 165 struct tun_struct *tun; 166 167 u32 rxhash; 168 u32 rps_rxhash; 169 int queue_index; 170 unsigned long updated; 171 }; 172 173 #define TUN_NUM_FLOW_ENTRIES 1024 174 175 /* Since the socket were moved to tun_file, to preserve the behavior of persist 176 * device, socket filter, sndbuf and vnet header size were restore when the 177 * file were attached to a persist device. 178 */ 179 struct tun_struct { 180 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 181 unsigned int numqueues; 182 unsigned int flags; 183 kuid_t owner; 184 kgid_t group; 185 186 struct net_device *dev; 187 netdev_features_t set_features; 188 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 189 NETIF_F_TSO6|NETIF_F_UFO) 190 191 int vnet_hdr_sz; 192 int sndbuf; 193 struct tap_filter txflt; 194 struct sock_fprog fprog; 195 /* protected by rtnl lock */ 196 bool filter_attached; 197 #ifdef TUN_DEBUG 198 int debug; 199 #endif 200 spinlock_t lock; 201 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 202 struct timer_list flow_gc_timer; 203 unsigned long ageing_time; 204 unsigned int numdisabled; 205 struct list_head disabled; 206 void *security; 207 u32 flow_count; 208 }; 209 210 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) 211 { 212 return __virtio16_to_cpu(tun->flags & TUN_VNET_LE, val); 213 } 214 215 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val) 216 { 217 return __cpu_to_virtio16(tun->flags & TUN_VNET_LE, val); 218 } 219 220 static inline u32 tun_hashfn(u32 rxhash) 221 { 222 return rxhash & 0x3ff; 223 } 224 225 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 226 { 227 struct tun_flow_entry *e; 228 229 hlist_for_each_entry_rcu(e, head, hash_link) { 230 if (e->rxhash == rxhash) 231 return e; 232 } 233 return NULL; 234 } 235 236 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 237 struct hlist_head *head, 238 u32 rxhash, u16 queue_index) 239 { 240 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 241 242 if (e) { 243 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 244 rxhash, queue_index); 245 e->updated = jiffies; 246 e->rxhash = rxhash; 247 e->rps_rxhash = 0; 248 e->queue_index = queue_index; 249 e->tun = tun; 250 hlist_add_head_rcu(&e->hash_link, head); 251 ++tun->flow_count; 252 } 253 return e; 254 } 255 256 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 257 { 258 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 259 e->rxhash, e->queue_index); 260 sock_rps_reset_flow_hash(e->rps_rxhash); 261 hlist_del_rcu(&e->hash_link); 262 kfree_rcu(e, rcu); 263 --tun->flow_count; 264 } 265 266 static void tun_flow_flush(struct tun_struct *tun) 267 { 268 int i; 269 270 spin_lock_bh(&tun->lock); 271 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 272 struct tun_flow_entry *e; 273 struct hlist_node *n; 274 275 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 276 tun_flow_delete(tun, e); 277 } 278 spin_unlock_bh(&tun->lock); 279 } 280 281 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 282 { 283 int i; 284 285 spin_lock_bh(&tun->lock); 286 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 287 struct tun_flow_entry *e; 288 struct hlist_node *n; 289 290 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 291 if (e->queue_index == queue_index) 292 tun_flow_delete(tun, e); 293 } 294 } 295 spin_unlock_bh(&tun->lock); 296 } 297 298 static void tun_flow_cleanup(unsigned long data) 299 { 300 struct tun_struct *tun = (struct tun_struct *)data; 301 unsigned long delay = tun->ageing_time; 302 unsigned long next_timer = jiffies + delay; 303 unsigned long count = 0; 304 int i; 305 306 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 307 308 spin_lock_bh(&tun->lock); 309 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 310 struct tun_flow_entry *e; 311 struct hlist_node *n; 312 313 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 314 unsigned long this_timer; 315 count++; 316 this_timer = e->updated + delay; 317 if (time_before_eq(this_timer, jiffies)) 318 tun_flow_delete(tun, e); 319 else if (time_before(this_timer, next_timer)) 320 next_timer = this_timer; 321 } 322 } 323 324 if (count) 325 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 326 spin_unlock_bh(&tun->lock); 327 } 328 329 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 330 struct tun_file *tfile) 331 { 332 struct hlist_head *head; 333 struct tun_flow_entry *e; 334 unsigned long delay = tun->ageing_time; 335 u16 queue_index = tfile->queue_index; 336 337 if (!rxhash) 338 return; 339 else 340 head = &tun->flows[tun_hashfn(rxhash)]; 341 342 rcu_read_lock(); 343 344 /* We may get a very small possibility of OOO during switching, not 345 * worth to optimize.*/ 346 if (tun->numqueues == 1 || tfile->detached) 347 goto unlock; 348 349 e = tun_flow_find(head, rxhash); 350 if (likely(e)) { 351 /* TODO: keep queueing to old queue until it's empty? */ 352 e->queue_index = queue_index; 353 e->updated = jiffies; 354 sock_rps_record_flow_hash(e->rps_rxhash); 355 } else { 356 spin_lock_bh(&tun->lock); 357 if (!tun_flow_find(head, rxhash) && 358 tun->flow_count < MAX_TAP_FLOWS) 359 tun_flow_create(tun, head, rxhash, queue_index); 360 361 if (!timer_pending(&tun->flow_gc_timer)) 362 mod_timer(&tun->flow_gc_timer, 363 round_jiffies_up(jiffies + delay)); 364 spin_unlock_bh(&tun->lock); 365 } 366 367 unlock: 368 rcu_read_unlock(); 369 } 370 371 /** 372 * Save the hash received in the stack receive path and update the 373 * flow_hash table accordingly. 374 */ 375 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 376 { 377 if (unlikely(e->rps_rxhash != hash)) { 378 sock_rps_reset_flow_hash(e->rps_rxhash); 379 e->rps_rxhash = hash; 380 } 381 } 382 383 /* We try to identify a flow through its rxhash first. The reason that 384 * we do not check rxq no. is because some cards(e.g 82599), chooses 385 * the rxq based on the txq where the last packet of the flow comes. As 386 * the userspace application move between processors, we may get a 387 * different rxq no. here. If we could not get rxhash, then we would 388 * hope the rxq no. may help here. 389 */ 390 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, 391 void *accel_priv, select_queue_fallback_t fallback) 392 { 393 struct tun_struct *tun = netdev_priv(dev); 394 struct tun_flow_entry *e; 395 u32 txq = 0; 396 u32 numqueues = 0; 397 398 rcu_read_lock(); 399 numqueues = ACCESS_ONCE(tun->numqueues); 400 401 txq = skb_get_hash(skb); 402 if (txq) { 403 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 404 if (e) { 405 tun_flow_save_rps_rxhash(e, txq); 406 txq = e->queue_index; 407 } else 408 /* use multiply and shift instead of expensive divide */ 409 txq = ((u64)txq * numqueues) >> 32; 410 } else if (likely(skb_rx_queue_recorded(skb))) { 411 txq = skb_get_rx_queue(skb); 412 while (unlikely(txq >= numqueues)) 413 txq -= numqueues; 414 } 415 416 rcu_read_unlock(); 417 return txq; 418 } 419 420 static inline bool tun_not_capable(struct tun_struct *tun) 421 { 422 const struct cred *cred = current_cred(); 423 struct net *net = dev_net(tun->dev); 424 425 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 426 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 427 !ns_capable(net->user_ns, CAP_NET_ADMIN); 428 } 429 430 static void tun_set_real_num_queues(struct tun_struct *tun) 431 { 432 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 433 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 434 } 435 436 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 437 { 438 tfile->detached = tun; 439 list_add_tail(&tfile->next, &tun->disabled); 440 ++tun->numdisabled; 441 } 442 443 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 444 { 445 struct tun_struct *tun = tfile->detached; 446 447 tfile->detached = NULL; 448 list_del_init(&tfile->next); 449 --tun->numdisabled; 450 return tun; 451 } 452 453 static void tun_queue_purge(struct tun_file *tfile) 454 { 455 skb_queue_purge(&tfile->sk.sk_receive_queue); 456 skb_queue_purge(&tfile->sk.sk_error_queue); 457 } 458 459 static void __tun_detach(struct tun_file *tfile, bool clean) 460 { 461 struct tun_file *ntfile; 462 struct tun_struct *tun; 463 464 tun = rtnl_dereference(tfile->tun); 465 466 if (tun && !tfile->detached) { 467 u16 index = tfile->queue_index; 468 BUG_ON(index >= tun->numqueues); 469 470 rcu_assign_pointer(tun->tfiles[index], 471 tun->tfiles[tun->numqueues - 1]); 472 ntfile = rtnl_dereference(tun->tfiles[index]); 473 ntfile->queue_index = index; 474 475 --tun->numqueues; 476 if (clean) { 477 RCU_INIT_POINTER(tfile->tun, NULL); 478 sock_put(&tfile->sk); 479 } else 480 tun_disable_queue(tun, tfile); 481 482 synchronize_net(); 483 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 484 /* Drop read queue */ 485 tun_queue_purge(tfile); 486 tun_set_real_num_queues(tun); 487 } else if (tfile->detached && clean) { 488 tun = tun_enable_queue(tfile); 489 sock_put(&tfile->sk); 490 } 491 492 if (clean) { 493 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 494 netif_carrier_off(tun->dev); 495 496 if (!(tun->flags & IFF_PERSIST) && 497 tun->dev->reg_state == NETREG_REGISTERED) 498 unregister_netdevice(tun->dev); 499 } 500 501 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 502 &tfile->socket.flags)); 503 sk_release_kernel(&tfile->sk); 504 } 505 } 506 507 static void tun_detach(struct tun_file *tfile, bool clean) 508 { 509 rtnl_lock(); 510 __tun_detach(tfile, clean); 511 rtnl_unlock(); 512 } 513 514 static void tun_detach_all(struct net_device *dev) 515 { 516 struct tun_struct *tun = netdev_priv(dev); 517 struct tun_file *tfile, *tmp; 518 int i, n = tun->numqueues; 519 520 for (i = 0; i < n; i++) { 521 tfile = rtnl_dereference(tun->tfiles[i]); 522 BUG_ON(!tfile); 523 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 524 RCU_INIT_POINTER(tfile->tun, NULL); 525 --tun->numqueues; 526 } 527 list_for_each_entry(tfile, &tun->disabled, next) { 528 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 529 RCU_INIT_POINTER(tfile->tun, NULL); 530 } 531 BUG_ON(tun->numqueues != 0); 532 533 synchronize_net(); 534 for (i = 0; i < n; i++) { 535 tfile = rtnl_dereference(tun->tfiles[i]); 536 /* Drop read queue */ 537 tun_queue_purge(tfile); 538 sock_put(&tfile->sk); 539 } 540 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 541 tun_enable_queue(tfile); 542 tun_queue_purge(tfile); 543 sock_put(&tfile->sk); 544 } 545 BUG_ON(tun->numdisabled != 0); 546 547 if (tun->flags & IFF_PERSIST) 548 module_put(THIS_MODULE); 549 } 550 551 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) 552 { 553 struct tun_file *tfile = file->private_data; 554 int err; 555 556 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 557 if (err < 0) 558 goto out; 559 560 err = -EINVAL; 561 if (rtnl_dereference(tfile->tun) && !tfile->detached) 562 goto out; 563 564 err = -EBUSY; 565 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1) 566 goto out; 567 568 err = -E2BIG; 569 if (!tfile->detached && 570 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 571 goto out; 572 573 err = 0; 574 575 /* Re-attach the filter to persist device */ 576 if (!skip_filter && (tun->filter_attached == true)) { 577 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 578 if (!err) 579 goto out; 580 } 581 tfile->queue_index = tun->numqueues; 582 rcu_assign_pointer(tfile->tun, tun); 583 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 584 tun->numqueues++; 585 586 if (tfile->detached) 587 tun_enable_queue(tfile); 588 else 589 sock_hold(&tfile->sk); 590 591 tun_set_real_num_queues(tun); 592 593 /* device is allowed to go away first, so no need to hold extra 594 * refcnt. 595 */ 596 597 out: 598 return err; 599 } 600 601 static struct tun_struct *__tun_get(struct tun_file *tfile) 602 { 603 struct tun_struct *tun; 604 605 rcu_read_lock(); 606 tun = rcu_dereference(tfile->tun); 607 if (tun) 608 dev_hold(tun->dev); 609 rcu_read_unlock(); 610 611 return tun; 612 } 613 614 static struct tun_struct *tun_get(struct file *file) 615 { 616 return __tun_get(file->private_data); 617 } 618 619 static void tun_put(struct tun_struct *tun) 620 { 621 dev_put(tun->dev); 622 } 623 624 /* TAP filtering */ 625 static void addr_hash_set(u32 *mask, const u8 *addr) 626 { 627 int n = ether_crc(ETH_ALEN, addr) >> 26; 628 mask[n >> 5] |= (1 << (n & 31)); 629 } 630 631 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 632 { 633 int n = ether_crc(ETH_ALEN, addr) >> 26; 634 return mask[n >> 5] & (1 << (n & 31)); 635 } 636 637 static int update_filter(struct tap_filter *filter, void __user *arg) 638 { 639 struct { u8 u[ETH_ALEN]; } *addr; 640 struct tun_filter uf; 641 int err, alen, n, nexact; 642 643 if (copy_from_user(&uf, arg, sizeof(uf))) 644 return -EFAULT; 645 646 if (!uf.count) { 647 /* Disabled */ 648 filter->count = 0; 649 return 0; 650 } 651 652 alen = ETH_ALEN * uf.count; 653 addr = kmalloc(alen, GFP_KERNEL); 654 if (!addr) 655 return -ENOMEM; 656 657 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 658 err = -EFAULT; 659 goto done; 660 } 661 662 /* The filter is updated without holding any locks. Which is 663 * perfectly safe. We disable it first and in the worst 664 * case we'll accept a few undesired packets. */ 665 filter->count = 0; 666 wmb(); 667 668 /* Use first set of addresses as an exact filter */ 669 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 670 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 671 672 nexact = n; 673 674 /* Remaining multicast addresses are hashed, 675 * unicast will leave the filter disabled. */ 676 memset(filter->mask, 0, sizeof(filter->mask)); 677 for (; n < uf.count; n++) { 678 if (!is_multicast_ether_addr(addr[n].u)) { 679 err = 0; /* no filter */ 680 goto done; 681 } 682 addr_hash_set(filter->mask, addr[n].u); 683 } 684 685 /* For ALLMULTI just set the mask to all ones. 686 * This overrides the mask populated above. */ 687 if ((uf.flags & TUN_FLT_ALLMULTI)) 688 memset(filter->mask, ~0, sizeof(filter->mask)); 689 690 /* Now enable the filter */ 691 wmb(); 692 filter->count = nexact; 693 694 /* Return the number of exact filters */ 695 err = nexact; 696 697 done: 698 kfree(addr); 699 return err; 700 } 701 702 /* Returns: 0 - drop, !=0 - accept */ 703 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 704 { 705 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 706 * at this point. */ 707 struct ethhdr *eh = (struct ethhdr *) skb->data; 708 int i; 709 710 /* Exact match */ 711 for (i = 0; i < filter->count; i++) 712 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 713 return 1; 714 715 /* Inexact match (multicast only) */ 716 if (is_multicast_ether_addr(eh->h_dest)) 717 return addr_hash_test(filter->mask, eh->h_dest); 718 719 return 0; 720 } 721 722 /* 723 * Checks whether the packet is accepted or not. 724 * Returns: 0 - drop, !=0 - accept 725 */ 726 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 727 { 728 if (!filter->count) 729 return 1; 730 731 return run_filter(filter, skb); 732 } 733 734 /* Network device part of the driver */ 735 736 static const struct ethtool_ops tun_ethtool_ops; 737 738 /* Net device detach from fd. */ 739 static void tun_net_uninit(struct net_device *dev) 740 { 741 tun_detach_all(dev); 742 } 743 744 /* Net device open. */ 745 static int tun_net_open(struct net_device *dev) 746 { 747 netif_tx_start_all_queues(dev); 748 return 0; 749 } 750 751 /* Net device close. */ 752 static int tun_net_close(struct net_device *dev) 753 { 754 netif_tx_stop_all_queues(dev); 755 return 0; 756 } 757 758 /* Net device start xmit */ 759 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 760 { 761 struct tun_struct *tun = netdev_priv(dev); 762 int txq = skb->queue_mapping; 763 struct tun_file *tfile; 764 u32 numqueues = 0; 765 766 rcu_read_lock(); 767 tfile = rcu_dereference(tun->tfiles[txq]); 768 numqueues = ACCESS_ONCE(tun->numqueues); 769 770 /* Drop packet if interface is not attached */ 771 if (txq >= numqueues) 772 goto drop; 773 774 if (numqueues == 1) { 775 /* Select queue was not called for the skbuff, so we extract the 776 * RPS hash and save it into the flow_table here. 777 */ 778 __u32 rxhash; 779 780 rxhash = skb_get_hash(skb); 781 if (rxhash) { 782 struct tun_flow_entry *e; 783 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], 784 rxhash); 785 if (e) 786 tun_flow_save_rps_rxhash(e, rxhash); 787 } 788 } 789 790 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 791 792 BUG_ON(!tfile); 793 794 /* Drop if the filter does not like it. 795 * This is a noop if the filter is disabled. 796 * Filter can be enabled only for the TAP devices. */ 797 if (!check_filter(&tun->txflt, skb)) 798 goto drop; 799 800 if (tfile->socket.sk->sk_filter && 801 sk_filter(tfile->socket.sk, skb)) 802 goto drop; 803 804 /* Limit the number of packets queued by dividing txq length with the 805 * number of queues. 806 */ 807 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues 808 >= dev->tx_queue_len) 809 goto drop; 810 811 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 812 goto drop; 813 814 if (skb->sk) { 815 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags); 816 sw_tx_timestamp(skb); 817 } 818 819 /* Orphan the skb - required as we might hang on to it 820 * for indefinite time. 821 */ 822 skb_orphan(skb); 823 824 nf_reset(skb); 825 826 /* Enqueue packet */ 827 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 828 829 /* Notify and wake up reader process */ 830 if (tfile->flags & TUN_FASYNC) 831 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 832 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 833 834 rcu_read_unlock(); 835 return NETDEV_TX_OK; 836 837 drop: 838 dev->stats.tx_dropped++; 839 skb_tx_error(skb); 840 kfree_skb(skb); 841 rcu_read_unlock(); 842 return NET_XMIT_DROP; 843 } 844 845 static void tun_net_mclist(struct net_device *dev) 846 { 847 /* 848 * This callback is supposed to deal with mc filter in 849 * _rx_ path and has nothing to do with the _tx_ path. 850 * In rx path we always accept everything userspace gives us. 851 */ 852 } 853 854 #define MIN_MTU 68 855 #define MAX_MTU 65535 856 857 static int 858 tun_net_change_mtu(struct net_device *dev, int new_mtu) 859 { 860 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 861 return -EINVAL; 862 dev->mtu = new_mtu; 863 return 0; 864 } 865 866 static netdev_features_t tun_net_fix_features(struct net_device *dev, 867 netdev_features_t features) 868 { 869 struct tun_struct *tun = netdev_priv(dev); 870 871 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 872 } 873 #ifdef CONFIG_NET_POLL_CONTROLLER 874 static void tun_poll_controller(struct net_device *dev) 875 { 876 /* 877 * Tun only receives frames when: 878 * 1) the char device endpoint gets data from user space 879 * 2) the tun socket gets a sendmsg call from user space 880 * Since both of those are synchronous operations, we are guaranteed 881 * never to have pending data when we poll for it 882 * so there is nothing to do here but return. 883 * We need this though so netpoll recognizes us as an interface that 884 * supports polling, which enables bridge devices in virt setups to 885 * still use netconsole 886 */ 887 return; 888 } 889 #endif 890 static const struct net_device_ops tun_netdev_ops = { 891 .ndo_uninit = tun_net_uninit, 892 .ndo_open = tun_net_open, 893 .ndo_stop = tun_net_close, 894 .ndo_start_xmit = tun_net_xmit, 895 .ndo_change_mtu = tun_net_change_mtu, 896 .ndo_fix_features = tun_net_fix_features, 897 .ndo_select_queue = tun_select_queue, 898 #ifdef CONFIG_NET_POLL_CONTROLLER 899 .ndo_poll_controller = tun_poll_controller, 900 #endif 901 }; 902 903 static const struct net_device_ops tap_netdev_ops = { 904 .ndo_uninit = tun_net_uninit, 905 .ndo_open = tun_net_open, 906 .ndo_stop = tun_net_close, 907 .ndo_start_xmit = tun_net_xmit, 908 .ndo_change_mtu = tun_net_change_mtu, 909 .ndo_fix_features = tun_net_fix_features, 910 .ndo_set_rx_mode = tun_net_mclist, 911 .ndo_set_mac_address = eth_mac_addr, 912 .ndo_validate_addr = eth_validate_addr, 913 .ndo_select_queue = tun_select_queue, 914 #ifdef CONFIG_NET_POLL_CONTROLLER 915 .ndo_poll_controller = tun_poll_controller, 916 #endif 917 }; 918 919 static void tun_flow_init(struct tun_struct *tun) 920 { 921 int i; 922 923 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 924 INIT_HLIST_HEAD(&tun->flows[i]); 925 926 tun->ageing_time = TUN_FLOW_EXPIRE; 927 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 928 mod_timer(&tun->flow_gc_timer, 929 round_jiffies_up(jiffies + tun->ageing_time)); 930 } 931 932 static void tun_flow_uninit(struct tun_struct *tun) 933 { 934 del_timer_sync(&tun->flow_gc_timer); 935 tun_flow_flush(tun); 936 } 937 938 /* Initialize net device. */ 939 static void tun_net_init(struct net_device *dev) 940 { 941 struct tun_struct *tun = netdev_priv(dev); 942 943 switch (tun->flags & TUN_TYPE_MASK) { 944 case IFF_TUN: 945 dev->netdev_ops = &tun_netdev_ops; 946 947 /* Point-to-Point TUN Device */ 948 dev->hard_header_len = 0; 949 dev->addr_len = 0; 950 dev->mtu = 1500; 951 952 /* Zero header length */ 953 dev->type = ARPHRD_NONE; 954 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 955 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 956 break; 957 958 case IFF_TAP: 959 dev->netdev_ops = &tap_netdev_ops; 960 /* Ethernet TAP Device */ 961 ether_setup(dev); 962 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 963 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 964 965 eth_hw_addr_random(dev); 966 967 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 968 break; 969 } 970 } 971 972 /* Character device part */ 973 974 /* Poll */ 975 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 976 { 977 struct tun_file *tfile = file->private_data; 978 struct tun_struct *tun = __tun_get(tfile); 979 struct sock *sk; 980 unsigned int mask = 0; 981 982 if (!tun) 983 return POLLERR; 984 985 sk = tfile->socket.sk; 986 987 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 988 989 poll_wait(file, sk_sleep(sk), wait); 990 991 if (!skb_queue_empty(&sk->sk_receive_queue)) 992 mask |= POLLIN | POLLRDNORM; 993 994 if (sock_writeable(sk) || 995 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 996 sock_writeable(sk))) 997 mask |= POLLOUT | POLLWRNORM; 998 999 if (tun->dev->reg_state != NETREG_REGISTERED) 1000 mask = POLLERR; 1001 1002 tun_put(tun); 1003 return mask; 1004 } 1005 1006 /* prepad is the amount to reserve at front. len is length after that. 1007 * linear is a hint as to how much to copy (usually headers). */ 1008 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 1009 size_t prepad, size_t len, 1010 size_t linear, int noblock) 1011 { 1012 struct sock *sk = tfile->socket.sk; 1013 struct sk_buff *skb; 1014 int err; 1015 1016 /* Under a page? Don't bother with paged skb. */ 1017 if (prepad + len < PAGE_SIZE || !linear) 1018 linear = len; 1019 1020 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 1021 &err, 0); 1022 if (!skb) 1023 return ERR_PTR(err); 1024 1025 skb_reserve(skb, prepad); 1026 skb_put(skb, linear); 1027 skb->data_len = len - linear; 1028 skb->len += len - linear; 1029 1030 return skb; 1031 } 1032 1033 /* Get packet from user space buffer */ 1034 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1035 void *msg_control, struct iov_iter *from, 1036 int noblock) 1037 { 1038 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1039 struct sk_buff *skb; 1040 size_t total_len = iov_iter_count(from); 1041 size_t len = total_len, align = NET_SKB_PAD, linear; 1042 struct virtio_net_hdr gso = { 0 }; 1043 int good_linear; 1044 int copylen; 1045 bool zerocopy = false; 1046 int err; 1047 u32 rxhash; 1048 ssize_t n; 1049 1050 if (!(tun->flags & IFF_NO_PI)) { 1051 if (len < sizeof(pi)) 1052 return -EINVAL; 1053 len -= sizeof(pi); 1054 1055 n = copy_from_iter(&pi, sizeof(pi), from); 1056 if (n != sizeof(pi)) 1057 return -EFAULT; 1058 } 1059 1060 if (tun->flags & IFF_VNET_HDR) { 1061 if (len < tun->vnet_hdr_sz) 1062 return -EINVAL; 1063 len -= tun->vnet_hdr_sz; 1064 1065 n = copy_from_iter(&gso, sizeof(gso), from); 1066 if (n != sizeof(gso)) 1067 return -EFAULT; 1068 1069 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1070 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len)) 1071 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2); 1072 1073 if (tun16_to_cpu(tun, gso.hdr_len) > len) 1074 return -EINVAL; 1075 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso)); 1076 } 1077 1078 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) { 1079 align += NET_IP_ALIGN; 1080 if (unlikely(len < ETH_HLEN || 1081 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN))) 1082 return -EINVAL; 1083 } 1084 1085 good_linear = SKB_MAX_HEAD(align); 1086 1087 if (msg_control) { 1088 struct iov_iter i = *from; 1089 1090 /* There are 256 bytes to be copied in skb, so there is 1091 * enough room for skb expand head in case it is used. 1092 * The rest of the buffer is mapped from userspace. 1093 */ 1094 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN; 1095 if (copylen > good_linear) 1096 copylen = good_linear; 1097 linear = copylen; 1098 iov_iter_advance(&i, copylen); 1099 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS) 1100 zerocopy = true; 1101 } 1102 1103 if (!zerocopy) { 1104 copylen = len; 1105 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear) 1106 linear = good_linear; 1107 else 1108 linear = tun16_to_cpu(tun, gso.hdr_len); 1109 } 1110 1111 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1112 if (IS_ERR(skb)) { 1113 if (PTR_ERR(skb) != -EAGAIN) 1114 tun->dev->stats.rx_dropped++; 1115 return PTR_ERR(skb); 1116 } 1117 1118 if (zerocopy) 1119 err = zerocopy_sg_from_iter(skb, from); 1120 else { 1121 err = skb_copy_datagram_from_iter(skb, 0, from, len); 1122 if (!err && msg_control) { 1123 struct ubuf_info *uarg = msg_control; 1124 uarg->callback(uarg, false); 1125 } 1126 } 1127 1128 if (err) { 1129 tun->dev->stats.rx_dropped++; 1130 kfree_skb(skb); 1131 return -EFAULT; 1132 } 1133 1134 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1135 if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start), 1136 tun16_to_cpu(tun, gso.csum_offset))) { 1137 tun->dev->stats.rx_frame_errors++; 1138 kfree_skb(skb); 1139 return -EINVAL; 1140 } 1141 } 1142 1143 switch (tun->flags & TUN_TYPE_MASK) { 1144 case IFF_TUN: 1145 if (tun->flags & IFF_NO_PI) { 1146 switch (skb->data[0] & 0xf0) { 1147 case 0x40: 1148 pi.proto = htons(ETH_P_IP); 1149 break; 1150 case 0x60: 1151 pi.proto = htons(ETH_P_IPV6); 1152 break; 1153 default: 1154 tun->dev->stats.rx_dropped++; 1155 kfree_skb(skb); 1156 return -EINVAL; 1157 } 1158 } 1159 1160 skb_reset_mac_header(skb); 1161 skb->protocol = pi.proto; 1162 skb->dev = tun->dev; 1163 break; 1164 case IFF_TAP: 1165 skb->protocol = eth_type_trans(skb, tun->dev); 1166 break; 1167 } 1168 1169 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1170 pr_debug("GSO!\n"); 1171 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1172 case VIRTIO_NET_HDR_GSO_TCPV4: 1173 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1174 break; 1175 case VIRTIO_NET_HDR_GSO_TCPV6: 1176 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1177 break; 1178 case VIRTIO_NET_HDR_GSO_UDP: 1179 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1180 break; 1181 default: 1182 tun->dev->stats.rx_frame_errors++; 1183 kfree_skb(skb); 1184 return -EINVAL; 1185 } 1186 1187 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1188 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1189 1190 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size); 1191 if (skb_shinfo(skb)->gso_size == 0) { 1192 tun->dev->stats.rx_frame_errors++; 1193 kfree_skb(skb); 1194 return -EINVAL; 1195 } 1196 1197 /* Header must be checked, and gso_segs computed. */ 1198 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1199 skb_shinfo(skb)->gso_segs = 0; 1200 } 1201 1202 /* copy skb_ubuf_info for callback when skb has no error */ 1203 if (zerocopy) { 1204 skb_shinfo(skb)->destructor_arg = msg_control; 1205 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1206 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1207 } 1208 1209 skb_reset_network_header(skb); 1210 skb_probe_transport_header(skb, 0); 1211 1212 rxhash = skb_get_hash(skb); 1213 netif_rx_ni(skb); 1214 1215 tun->dev->stats.rx_packets++; 1216 tun->dev->stats.rx_bytes += len; 1217 1218 tun_flow_update(tun, rxhash, tfile); 1219 return total_len; 1220 } 1221 1222 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from) 1223 { 1224 struct file *file = iocb->ki_filp; 1225 struct tun_struct *tun = tun_get(file); 1226 struct tun_file *tfile = file->private_data; 1227 ssize_t result; 1228 1229 if (!tun) 1230 return -EBADFD; 1231 1232 result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK); 1233 1234 tun_put(tun); 1235 return result; 1236 } 1237 1238 /* Put packet to the user space buffer */ 1239 static ssize_t tun_put_user(struct tun_struct *tun, 1240 struct tun_file *tfile, 1241 struct sk_buff *skb, 1242 struct iov_iter *iter) 1243 { 1244 struct tun_pi pi = { 0, skb->protocol }; 1245 ssize_t total; 1246 int vlan_offset = 0; 1247 int vlan_hlen = 0; 1248 int vnet_hdr_sz = 0; 1249 1250 if (vlan_tx_tag_present(skb)) 1251 vlan_hlen = VLAN_HLEN; 1252 1253 if (tun->flags & IFF_VNET_HDR) 1254 vnet_hdr_sz = tun->vnet_hdr_sz; 1255 1256 total = skb->len + vlan_hlen + vnet_hdr_sz; 1257 1258 if (!(tun->flags & IFF_NO_PI)) { 1259 if (iov_iter_count(iter) < sizeof(pi)) 1260 return -EINVAL; 1261 1262 total += sizeof(pi); 1263 if (iov_iter_count(iter) < total) { 1264 /* Packet will be striped */ 1265 pi.flags |= TUN_PKT_STRIP; 1266 } 1267 1268 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi)) 1269 return -EFAULT; 1270 } 1271 1272 if (vnet_hdr_sz) { 1273 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1274 if (iov_iter_count(iter) < vnet_hdr_sz) 1275 return -EINVAL; 1276 1277 if (skb_is_gso(skb)) { 1278 struct skb_shared_info *sinfo = skb_shinfo(skb); 1279 1280 /* This is a hint as to how much should be linear. */ 1281 gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb)); 1282 gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size); 1283 if (sinfo->gso_type & SKB_GSO_TCPV4) 1284 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1285 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1286 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1287 else if (sinfo->gso_type & SKB_GSO_UDP) 1288 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1289 else { 1290 pr_err("unexpected GSO type: " 1291 "0x%x, gso_size %d, hdr_len %d\n", 1292 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size), 1293 tun16_to_cpu(tun, gso.hdr_len)); 1294 print_hex_dump(KERN_ERR, "tun: ", 1295 DUMP_PREFIX_NONE, 1296 16, 1, skb->head, 1297 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true); 1298 WARN_ON_ONCE(1); 1299 return -EINVAL; 1300 } 1301 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1302 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1303 } else 1304 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1305 1306 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1307 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1308 gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) + 1309 vlan_hlen); 1310 gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset); 1311 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1312 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1313 } /* else everything is zero */ 1314 1315 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso)) 1316 return -EFAULT; 1317 1318 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso)); 1319 } 1320 1321 if (vlan_hlen) { 1322 int ret; 1323 struct { 1324 __be16 h_vlan_proto; 1325 __be16 h_vlan_TCI; 1326 } veth; 1327 1328 veth.h_vlan_proto = skb->vlan_proto; 1329 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 1330 1331 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1332 1333 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset); 1334 if (ret || !iov_iter_count(iter)) 1335 goto done; 1336 1337 ret = copy_to_iter(&veth, sizeof(veth), iter); 1338 if (ret != sizeof(veth) || !iov_iter_count(iter)) 1339 goto done; 1340 } 1341 1342 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset); 1343 1344 done: 1345 tun->dev->stats.tx_packets++; 1346 tun->dev->stats.tx_bytes += skb->len + vlan_hlen; 1347 1348 return total; 1349 } 1350 1351 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1352 struct iov_iter *to, 1353 int noblock) 1354 { 1355 struct sk_buff *skb; 1356 ssize_t ret; 1357 int peeked, err, off = 0; 1358 1359 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1360 1361 if (!iov_iter_count(to)) 1362 return 0; 1363 1364 if (tun->dev->reg_state != NETREG_REGISTERED) 1365 return -EIO; 1366 1367 /* Read frames from queue */ 1368 skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0, 1369 &peeked, &off, &err); 1370 if (!skb) 1371 return 0; 1372 1373 ret = tun_put_user(tun, tfile, skb, to); 1374 if (unlikely(ret < 0)) 1375 kfree_skb(skb); 1376 else 1377 consume_skb(skb); 1378 1379 return ret; 1380 } 1381 1382 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1383 { 1384 struct file *file = iocb->ki_filp; 1385 struct tun_file *tfile = file->private_data; 1386 struct tun_struct *tun = __tun_get(tfile); 1387 ssize_t len = iov_iter_count(to), ret; 1388 1389 if (!tun) 1390 return -EBADFD; 1391 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK); 1392 ret = min_t(ssize_t, ret, len); 1393 if (ret > 0) 1394 iocb->ki_pos = ret; 1395 tun_put(tun); 1396 return ret; 1397 } 1398 1399 static void tun_free_netdev(struct net_device *dev) 1400 { 1401 struct tun_struct *tun = netdev_priv(dev); 1402 1403 BUG_ON(!(list_empty(&tun->disabled))); 1404 tun_flow_uninit(tun); 1405 security_tun_dev_free_security(tun->security); 1406 free_netdev(dev); 1407 } 1408 1409 static void tun_setup(struct net_device *dev) 1410 { 1411 struct tun_struct *tun = netdev_priv(dev); 1412 1413 tun->owner = INVALID_UID; 1414 tun->group = INVALID_GID; 1415 1416 dev->ethtool_ops = &tun_ethtool_ops; 1417 dev->destructor = tun_free_netdev; 1418 } 1419 1420 /* Trivial set of netlink ops to allow deleting tun or tap 1421 * device with netlink. 1422 */ 1423 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1424 { 1425 return -EINVAL; 1426 } 1427 1428 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1429 .kind = DRV_NAME, 1430 .priv_size = sizeof(struct tun_struct), 1431 .setup = tun_setup, 1432 .validate = tun_validate, 1433 }; 1434 1435 static void tun_sock_write_space(struct sock *sk) 1436 { 1437 struct tun_file *tfile; 1438 wait_queue_head_t *wqueue; 1439 1440 if (!sock_writeable(sk)) 1441 return; 1442 1443 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1444 return; 1445 1446 wqueue = sk_sleep(sk); 1447 if (wqueue && waitqueue_active(wqueue)) 1448 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1449 POLLWRNORM | POLLWRBAND); 1450 1451 tfile = container_of(sk, struct tun_file, sk); 1452 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1453 } 1454 1455 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1456 struct msghdr *m, size_t total_len) 1457 { 1458 int ret; 1459 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1460 struct tun_struct *tun = __tun_get(tfile); 1461 1462 if (!tun) 1463 return -EBADFD; 1464 1465 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter, 1466 m->msg_flags & MSG_DONTWAIT); 1467 tun_put(tun); 1468 return ret; 1469 } 1470 1471 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1472 struct msghdr *m, size_t total_len, 1473 int flags) 1474 { 1475 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1476 struct tun_struct *tun = __tun_get(tfile); 1477 int ret; 1478 1479 if (!tun) 1480 return -EBADFD; 1481 1482 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1483 ret = -EINVAL; 1484 goto out; 1485 } 1486 if (flags & MSG_ERRQUEUE) { 1487 ret = sock_recv_errqueue(sock->sk, m, total_len, 1488 SOL_PACKET, TUN_TX_TIMESTAMP); 1489 goto out; 1490 } 1491 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT); 1492 if (ret > 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 int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1558 { 1559 struct tun_struct *tun; 1560 struct tun_file *tfile = file->private_data; 1561 struct net_device *dev; 1562 int err; 1563 1564 if (tfile->detached) 1565 return -EINVAL; 1566 1567 dev = __dev_get_by_name(net, ifr->ifr_name); 1568 if (dev) { 1569 if (ifr->ifr_flags & IFF_TUN_EXCL) 1570 return -EBUSY; 1571 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1572 tun = netdev_priv(dev); 1573 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1574 tun = netdev_priv(dev); 1575 else 1576 return -EINVAL; 1577 1578 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1579 !!(tun->flags & IFF_MULTI_QUEUE)) 1580 return -EINVAL; 1581 1582 if (tun_not_capable(tun)) 1583 return -EPERM; 1584 err = security_tun_dev_open(tun->security); 1585 if (err < 0) 1586 return err; 1587 1588 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1589 if (err < 0) 1590 return err; 1591 1592 if (tun->flags & IFF_MULTI_QUEUE && 1593 (tun->numqueues + tun->numdisabled > 1)) { 1594 /* One or more queue has already been attached, no need 1595 * to initialize the device again. 1596 */ 1597 return 0; 1598 } 1599 } 1600 else { 1601 char *name; 1602 unsigned long flags = 0; 1603 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1604 MAX_TAP_QUEUES : 1; 1605 1606 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1607 return -EPERM; 1608 err = security_tun_dev_create(); 1609 if (err < 0) 1610 return err; 1611 1612 /* Set dev type */ 1613 if (ifr->ifr_flags & IFF_TUN) { 1614 /* TUN device */ 1615 flags |= IFF_TUN; 1616 name = "tun%d"; 1617 } else if (ifr->ifr_flags & IFF_TAP) { 1618 /* TAP device */ 1619 flags |= IFF_TAP; 1620 name = "tap%d"; 1621 } else 1622 return -EINVAL; 1623 1624 if (*ifr->ifr_name) 1625 name = ifr->ifr_name; 1626 1627 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1628 NET_NAME_UNKNOWN, tun_setup, queues, 1629 queues); 1630 1631 if (!dev) 1632 return -ENOMEM; 1633 1634 dev_net_set(dev, net); 1635 dev->rtnl_link_ops = &tun_link_ops; 1636 dev->ifindex = tfile->ifindex; 1637 1638 tun = netdev_priv(dev); 1639 tun->dev = dev; 1640 tun->flags = flags; 1641 tun->txflt.count = 0; 1642 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1643 1644 tun->filter_attached = false; 1645 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1646 1647 spin_lock_init(&tun->lock); 1648 1649 err = security_tun_dev_alloc_security(&tun->security); 1650 if (err < 0) 1651 goto err_free_dev; 1652 1653 tun_net_init(dev); 1654 tun_flow_init(tun); 1655 1656 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1657 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1658 NETIF_F_HW_VLAN_STAG_TX; 1659 dev->features = dev->hw_features; 1660 dev->vlan_features = dev->features & 1661 ~(NETIF_F_HW_VLAN_CTAG_TX | 1662 NETIF_F_HW_VLAN_STAG_TX); 1663 1664 INIT_LIST_HEAD(&tun->disabled); 1665 err = tun_attach(tun, file, false); 1666 if (err < 0) 1667 goto err_free_flow; 1668 1669 err = register_netdevice(tun->dev); 1670 if (err < 0) 1671 goto err_detach; 1672 1673 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1674 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1675 device_create_file(&tun->dev->dev, &dev_attr_group)) 1676 pr_err("Failed to create tun sysfs files\n"); 1677 } 1678 1679 netif_carrier_on(tun->dev); 1680 1681 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1682 1683 tun->flags = (tun->flags & ~TUN_FEATURES) | 1684 (ifr->ifr_flags & TUN_FEATURES); 1685 1686 /* Make sure persistent devices do not get stuck in 1687 * xoff state. 1688 */ 1689 if (netif_running(tun->dev)) 1690 netif_tx_wake_all_queues(tun->dev); 1691 1692 strcpy(ifr->ifr_name, tun->dev->name); 1693 return 0; 1694 1695 err_detach: 1696 tun_detach_all(dev); 1697 err_free_flow: 1698 tun_flow_uninit(tun); 1699 security_tun_dev_free_security(tun->security); 1700 err_free_dev: 1701 free_netdev(dev); 1702 return err; 1703 } 1704 1705 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1706 struct ifreq *ifr) 1707 { 1708 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1709 1710 strcpy(ifr->ifr_name, tun->dev->name); 1711 1712 ifr->ifr_flags = tun_flags(tun); 1713 1714 } 1715 1716 /* This is like a cut-down ethtool ops, except done via tun fd so no 1717 * privs required. */ 1718 static int set_offload(struct tun_struct *tun, unsigned long arg) 1719 { 1720 netdev_features_t features = 0; 1721 1722 if (arg & TUN_F_CSUM) { 1723 features |= NETIF_F_HW_CSUM; 1724 arg &= ~TUN_F_CSUM; 1725 1726 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1727 if (arg & TUN_F_TSO_ECN) { 1728 features |= NETIF_F_TSO_ECN; 1729 arg &= ~TUN_F_TSO_ECN; 1730 } 1731 if (arg & TUN_F_TSO4) 1732 features |= NETIF_F_TSO; 1733 if (arg & TUN_F_TSO6) 1734 features |= NETIF_F_TSO6; 1735 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1736 } 1737 1738 if (arg & TUN_F_UFO) { 1739 features |= NETIF_F_UFO; 1740 arg &= ~TUN_F_UFO; 1741 } 1742 } 1743 1744 /* This gives the user a way to test for new features in future by 1745 * trying to set them. */ 1746 if (arg) 1747 return -EINVAL; 1748 1749 tun->set_features = features; 1750 netdev_update_features(tun->dev); 1751 1752 return 0; 1753 } 1754 1755 static void tun_detach_filter(struct tun_struct *tun, int n) 1756 { 1757 int i; 1758 struct tun_file *tfile; 1759 1760 for (i = 0; i < n; i++) { 1761 tfile = rtnl_dereference(tun->tfiles[i]); 1762 sk_detach_filter(tfile->socket.sk); 1763 } 1764 1765 tun->filter_attached = false; 1766 } 1767 1768 static int tun_attach_filter(struct tun_struct *tun) 1769 { 1770 int i, ret = 0; 1771 struct tun_file *tfile; 1772 1773 for (i = 0; i < tun->numqueues; i++) { 1774 tfile = rtnl_dereference(tun->tfiles[i]); 1775 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1776 if (ret) { 1777 tun_detach_filter(tun, i); 1778 return ret; 1779 } 1780 } 1781 1782 tun->filter_attached = true; 1783 return ret; 1784 } 1785 1786 static void tun_set_sndbuf(struct tun_struct *tun) 1787 { 1788 struct tun_file *tfile; 1789 int i; 1790 1791 for (i = 0; i < tun->numqueues; i++) { 1792 tfile = rtnl_dereference(tun->tfiles[i]); 1793 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1794 } 1795 } 1796 1797 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1798 { 1799 struct tun_file *tfile = file->private_data; 1800 struct tun_struct *tun; 1801 int ret = 0; 1802 1803 rtnl_lock(); 1804 1805 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1806 tun = tfile->detached; 1807 if (!tun) { 1808 ret = -EINVAL; 1809 goto unlock; 1810 } 1811 ret = security_tun_dev_attach_queue(tun->security); 1812 if (ret < 0) 1813 goto unlock; 1814 ret = tun_attach(tun, file, false); 1815 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1816 tun = rtnl_dereference(tfile->tun); 1817 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached) 1818 ret = -EINVAL; 1819 else 1820 __tun_detach(tfile, false); 1821 } else 1822 ret = -EINVAL; 1823 1824 unlock: 1825 rtnl_unlock(); 1826 return ret; 1827 } 1828 1829 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1830 unsigned long arg, int ifreq_len) 1831 { 1832 struct tun_file *tfile = file->private_data; 1833 struct tun_struct *tun; 1834 void __user* argp = (void __user*)arg; 1835 struct ifreq ifr; 1836 kuid_t owner; 1837 kgid_t group; 1838 int sndbuf; 1839 int vnet_hdr_sz; 1840 unsigned int ifindex; 1841 int le; 1842 int ret; 1843 1844 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1845 if (copy_from_user(&ifr, argp, ifreq_len)) 1846 return -EFAULT; 1847 } else { 1848 memset(&ifr, 0, sizeof(ifr)); 1849 } 1850 if (cmd == TUNGETFEATURES) { 1851 /* Currently this just means: "what IFF flags are valid?". 1852 * This is needed because we never checked for invalid flags on 1853 * TUNSETIFF. 1854 */ 1855 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES, 1856 (unsigned int __user*)argp); 1857 } else if (cmd == TUNSETQUEUE) 1858 return tun_set_queue(file, &ifr); 1859 1860 ret = 0; 1861 rtnl_lock(); 1862 1863 tun = __tun_get(tfile); 1864 if (cmd == TUNSETIFF && !tun) { 1865 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1866 1867 ret = tun_set_iff(tfile->net, file, &ifr); 1868 1869 if (ret) 1870 goto unlock; 1871 1872 if (copy_to_user(argp, &ifr, ifreq_len)) 1873 ret = -EFAULT; 1874 goto unlock; 1875 } 1876 if (cmd == TUNSETIFINDEX) { 1877 ret = -EPERM; 1878 if (tun) 1879 goto unlock; 1880 1881 ret = -EFAULT; 1882 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1883 goto unlock; 1884 1885 ret = 0; 1886 tfile->ifindex = ifindex; 1887 goto unlock; 1888 } 1889 1890 ret = -EBADFD; 1891 if (!tun) 1892 goto unlock; 1893 1894 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1895 1896 ret = 0; 1897 switch (cmd) { 1898 case TUNGETIFF: 1899 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1900 1901 if (tfile->detached) 1902 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1903 if (!tfile->socket.sk->sk_filter) 1904 ifr.ifr_flags |= IFF_NOFILTER; 1905 1906 if (copy_to_user(argp, &ifr, ifreq_len)) 1907 ret = -EFAULT; 1908 break; 1909 1910 case TUNSETNOCSUM: 1911 /* Disable/Enable checksum */ 1912 1913 /* [unimplemented] */ 1914 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1915 arg ? "disabled" : "enabled"); 1916 break; 1917 1918 case TUNSETPERSIST: 1919 /* Disable/Enable persist mode. Keep an extra reference to the 1920 * module to prevent the module being unprobed. 1921 */ 1922 if (arg && !(tun->flags & IFF_PERSIST)) { 1923 tun->flags |= IFF_PERSIST; 1924 __module_get(THIS_MODULE); 1925 } 1926 if (!arg && (tun->flags & IFF_PERSIST)) { 1927 tun->flags &= ~IFF_PERSIST; 1928 module_put(THIS_MODULE); 1929 } 1930 1931 tun_debug(KERN_INFO, tun, "persist %s\n", 1932 arg ? "enabled" : "disabled"); 1933 break; 1934 1935 case TUNSETOWNER: 1936 /* Set owner of the device */ 1937 owner = make_kuid(current_user_ns(), arg); 1938 if (!uid_valid(owner)) { 1939 ret = -EINVAL; 1940 break; 1941 } 1942 tun->owner = owner; 1943 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1944 from_kuid(&init_user_ns, tun->owner)); 1945 break; 1946 1947 case TUNSETGROUP: 1948 /* Set group of the device */ 1949 group = make_kgid(current_user_ns(), arg); 1950 if (!gid_valid(group)) { 1951 ret = -EINVAL; 1952 break; 1953 } 1954 tun->group = group; 1955 tun_debug(KERN_INFO, tun, "group set to %u\n", 1956 from_kgid(&init_user_ns, tun->group)); 1957 break; 1958 1959 case TUNSETLINK: 1960 /* Only allow setting the type when the interface is down */ 1961 if (tun->dev->flags & IFF_UP) { 1962 tun_debug(KERN_INFO, tun, 1963 "Linktype set failed because interface is up\n"); 1964 ret = -EBUSY; 1965 } else { 1966 tun->dev->type = (int) arg; 1967 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1968 tun->dev->type); 1969 ret = 0; 1970 } 1971 break; 1972 1973 #ifdef TUN_DEBUG 1974 case TUNSETDEBUG: 1975 tun->debug = arg; 1976 break; 1977 #endif 1978 case TUNSETOFFLOAD: 1979 ret = set_offload(tun, arg); 1980 break; 1981 1982 case TUNSETTXFILTER: 1983 /* Can be set only for TAPs */ 1984 ret = -EINVAL; 1985 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 1986 break; 1987 ret = update_filter(&tun->txflt, (void __user *)arg); 1988 break; 1989 1990 case SIOCGIFHWADDR: 1991 /* Get hw address */ 1992 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 1993 ifr.ifr_hwaddr.sa_family = tun->dev->type; 1994 if (copy_to_user(argp, &ifr, ifreq_len)) 1995 ret = -EFAULT; 1996 break; 1997 1998 case SIOCSIFHWADDR: 1999 /* Set hw address */ 2000 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 2001 ifr.ifr_hwaddr.sa_data); 2002 2003 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2004 break; 2005 2006 case TUNGETSNDBUF: 2007 sndbuf = tfile->socket.sk->sk_sndbuf; 2008 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2009 ret = -EFAULT; 2010 break; 2011 2012 case TUNSETSNDBUF: 2013 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2014 ret = -EFAULT; 2015 break; 2016 } 2017 2018 tun->sndbuf = sndbuf; 2019 tun_set_sndbuf(tun); 2020 break; 2021 2022 case TUNGETVNETHDRSZ: 2023 vnet_hdr_sz = tun->vnet_hdr_sz; 2024 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2025 ret = -EFAULT; 2026 break; 2027 2028 case TUNSETVNETHDRSZ: 2029 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2030 ret = -EFAULT; 2031 break; 2032 } 2033 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2034 ret = -EINVAL; 2035 break; 2036 } 2037 2038 tun->vnet_hdr_sz = vnet_hdr_sz; 2039 break; 2040 2041 case TUNGETVNETLE: 2042 le = !!(tun->flags & TUN_VNET_LE); 2043 if (put_user(le, (int __user *)argp)) 2044 ret = -EFAULT; 2045 break; 2046 2047 case TUNSETVNETLE: 2048 if (get_user(le, (int __user *)argp)) { 2049 ret = -EFAULT; 2050 break; 2051 } 2052 if (le) 2053 tun->flags |= TUN_VNET_LE; 2054 else 2055 tun->flags &= ~TUN_VNET_LE; 2056 break; 2057 2058 case TUNATTACHFILTER: 2059 /* Can be set only for TAPs */ 2060 ret = -EINVAL; 2061 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2062 break; 2063 ret = -EFAULT; 2064 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2065 break; 2066 2067 ret = tun_attach_filter(tun); 2068 break; 2069 2070 case TUNDETACHFILTER: 2071 /* Can be set only for TAPs */ 2072 ret = -EINVAL; 2073 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2074 break; 2075 ret = 0; 2076 tun_detach_filter(tun, tun->numqueues); 2077 break; 2078 2079 case TUNGETFILTER: 2080 ret = -EINVAL; 2081 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2082 break; 2083 ret = -EFAULT; 2084 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2085 break; 2086 ret = 0; 2087 break; 2088 2089 default: 2090 ret = -EINVAL; 2091 break; 2092 } 2093 2094 unlock: 2095 rtnl_unlock(); 2096 if (tun) 2097 tun_put(tun); 2098 return ret; 2099 } 2100 2101 static long tun_chr_ioctl(struct file *file, 2102 unsigned int cmd, unsigned long arg) 2103 { 2104 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2105 } 2106 2107 #ifdef CONFIG_COMPAT 2108 static long tun_chr_compat_ioctl(struct file *file, 2109 unsigned int cmd, unsigned long arg) 2110 { 2111 switch (cmd) { 2112 case TUNSETIFF: 2113 case TUNGETIFF: 2114 case TUNSETTXFILTER: 2115 case TUNGETSNDBUF: 2116 case TUNSETSNDBUF: 2117 case SIOCGIFHWADDR: 2118 case SIOCSIFHWADDR: 2119 arg = (unsigned long)compat_ptr(arg); 2120 break; 2121 default: 2122 arg = (compat_ulong_t)arg; 2123 break; 2124 } 2125 2126 /* 2127 * compat_ifreq is shorter than ifreq, so we must not access beyond 2128 * the end of that structure. All fields that are used in this 2129 * driver are compatible though, we don't need to convert the 2130 * contents. 2131 */ 2132 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2133 } 2134 #endif /* CONFIG_COMPAT */ 2135 2136 static int tun_chr_fasync(int fd, struct file *file, int on) 2137 { 2138 struct tun_file *tfile = file->private_data; 2139 int ret; 2140 2141 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2142 goto out; 2143 2144 if (on) { 2145 __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2146 tfile->flags |= TUN_FASYNC; 2147 } else 2148 tfile->flags &= ~TUN_FASYNC; 2149 ret = 0; 2150 out: 2151 return ret; 2152 } 2153 2154 static int tun_chr_open(struct inode *inode, struct file * file) 2155 { 2156 struct tun_file *tfile; 2157 2158 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2159 2160 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2161 &tun_proto); 2162 if (!tfile) 2163 return -ENOMEM; 2164 RCU_INIT_POINTER(tfile->tun, NULL); 2165 tfile->net = get_net(current->nsproxy->net_ns); 2166 tfile->flags = 0; 2167 tfile->ifindex = 0; 2168 2169 init_waitqueue_head(&tfile->wq.wait); 2170 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq); 2171 2172 tfile->socket.file = file; 2173 tfile->socket.ops = &tun_socket_ops; 2174 2175 sock_init_data(&tfile->socket, &tfile->sk); 2176 sk_change_net(&tfile->sk, tfile->net); 2177 2178 tfile->sk.sk_write_space = tun_sock_write_space; 2179 tfile->sk.sk_sndbuf = INT_MAX; 2180 2181 file->private_data = tfile; 2182 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2183 INIT_LIST_HEAD(&tfile->next); 2184 2185 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2186 2187 return 0; 2188 } 2189 2190 static int tun_chr_close(struct inode *inode, struct file *file) 2191 { 2192 struct tun_file *tfile = file->private_data; 2193 struct net *net = tfile->net; 2194 2195 tun_detach(tfile, true); 2196 put_net(net); 2197 2198 return 0; 2199 } 2200 2201 #ifdef CONFIG_PROC_FS 2202 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f) 2203 { 2204 struct tun_struct *tun; 2205 struct ifreq ifr; 2206 2207 memset(&ifr, 0, sizeof(ifr)); 2208 2209 rtnl_lock(); 2210 tun = tun_get(f); 2211 if (tun) 2212 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 2213 rtnl_unlock(); 2214 2215 if (tun) 2216 tun_put(tun); 2217 2218 seq_printf(m, "iff:\t%s\n", ifr.ifr_name); 2219 } 2220 #endif 2221 2222 static const struct file_operations tun_fops = { 2223 .owner = THIS_MODULE, 2224 .llseek = no_llseek, 2225 .read = new_sync_read, 2226 .write = new_sync_write, 2227 .read_iter = tun_chr_read_iter, 2228 .write_iter = tun_chr_write_iter, 2229 .poll = tun_chr_poll, 2230 .unlocked_ioctl = tun_chr_ioctl, 2231 #ifdef CONFIG_COMPAT 2232 .compat_ioctl = tun_chr_compat_ioctl, 2233 #endif 2234 .open = tun_chr_open, 2235 .release = tun_chr_close, 2236 .fasync = tun_chr_fasync, 2237 #ifdef CONFIG_PROC_FS 2238 .show_fdinfo = tun_chr_show_fdinfo, 2239 #endif 2240 }; 2241 2242 static struct miscdevice tun_miscdev = { 2243 .minor = TUN_MINOR, 2244 .name = "tun", 2245 .nodename = "net/tun", 2246 .fops = &tun_fops, 2247 }; 2248 2249 /* ethtool interface */ 2250 2251 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2252 { 2253 cmd->supported = 0; 2254 cmd->advertising = 0; 2255 ethtool_cmd_speed_set(cmd, SPEED_10); 2256 cmd->duplex = DUPLEX_FULL; 2257 cmd->port = PORT_TP; 2258 cmd->phy_address = 0; 2259 cmd->transceiver = XCVR_INTERNAL; 2260 cmd->autoneg = AUTONEG_DISABLE; 2261 cmd->maxtxpkt = 0; 2262 cmd->maxrxpkt = 0; 2263 return 0; 2264 } 2265 2266 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2267 { 2268 struct tun_struct *tun = netdev_priv(dev); 2269 2270 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2271 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2272 2273 switch (tun->flags & TUN_TYPE_MASK) { 2274 case IFF_TUN: 2275 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2276 break; 2277 case IFF_TAP: 2278 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2279 break; 2280 } 2281 } 2282 2283 static u32 tun_get_msglevel(struct net_device *dev) 2284 { 2285 #ifdef TUN_DEBUG 2286 struct tun_struct *tun = netdev_priv(dev); 2287 return tun->debug; 2288 #else 2289 return -EOPNOTSUPP; 2290 #endif 2291 } 2292 2293 static void tun_set_msglevel(struct net_device *dev, u32 value) 2294 { 2295 #ifdef TUN_DEBUG 2296 struct tun_struct *tun = netdev_priv(dev); 2297 tun->debug = value; 2298 #endif 2299 } 2300 2301 static const struct ethtool_ops tun_ethtool_ops = { 2302 .get_settings = tun_get_settings, 2303 .get_drvinfo = tun_get_drvinfo, 2304 .get_msglevel = tun_get_msglevel, 2305 .set_msglevel = tun_set_msglevel, 2306 .get_link = ethtool_op_get_link, 2307 .get_ts_info = ethtool_op_get_ts_info, 2308 }; 2309 2310 2311 static int __init tun_init(void) 2312 { 2313 int ret = 0; 2314 2315 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2316 pr_info("%s\n", DRV_COPYRIGHT); 2317 2318 ret = rtnl_link_register(&tun_link_ops); 2319 if (ret) { 2320 pr_err("Can't register link_ops\n"); 2321 goto err_linkops; 2322 } 2323 2324 ret = misc_register(&tun_miscdev); 2325 if (ret) { 2326 pr_err("Can't register misc device %d\n", TUN_MINOR); 2327 goto err_misc; 2328 } 2329 return 0; 2330 err_misc: 2331 rtnl_link_unregister(&tun_link_ops); 2332 err_linkops: 2333 return ret; 2334 } 2335 2336 static void tun_cleanup(void) 2337 { 2338 misc_deregister(&tun_miscdev); 2339 rtnl_link_unregister(&tun_link_ops); 2340 } 2341 2342 /* Get an underlying socket object from tun file. Returns error unless file is 2343 * attached to a device. The returned object works like a packet socket, it 2344 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2345 * holding a reference to the file for as long as the socket is in use. */ 2346 struct socket *tun_get_socket(struct file *file) 2347 { 2348 struct tun_file *tfile; 2349 if (file->f_op != &tun_fops) 2350 return ERR_PTR(-EINVAL); 2351 tfile = file->private_data; 2352 if (!tfile) 2353 return ERR_PTR(-EBADFD); 2354 return &tfile->socket; 2355 } 2356 EXPORT_SYMBOL_GPL(tun_get_socket); 2357 2358 module_init(tun_init); 2359 module_exit(tun_cleanup); 2360 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2361 MODULE_AUTHOR(DRV_COPYRIGHT); 2362 MODULE_LICENSE("GPL"); 2363 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2364 MODULE_ALIAS("devname:net/tun"); 2365