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/ipv6.h> 69 #include <net/net_namespace.h> 70 #include <net/netns/generic.h> 71 #include <net/rtnetlink.h> 72 #include <net/sock.h> 73 #include <linux/seq_file.h> 74 #include <linux/uio.h> 75 76 #include <asm/uaccess.h> 77 78 /* Uncomment to enable debugging */ 79 /* #define TUN_DEBUG 1 */ 80 81 #ifdef TUN_DEBUG 82 static int debug; 83 84 #define tun_debug(level, tun, fmt, args...) \ 85 do { \ 86 if (tun->debug) \ 87 netdev_printk(level, tun->dev, fmt, ##args); \ 88 } while (0) 89 #define DBG1(level, fmt, args...) \ 90 do { \ 91 if (debug == 2) \ 92 printk(level fmt, ##args); \ 93 } while (0) 94 #else 95 #define tun_debug(level, tun, fmt, args...) \ 96 do { \ 97 if (0) \ 98 netdev_printk(level, tun->dev, fmt, ##args); \ 99 } while (0) 100 #define DBG1(level, fmt, args...) \ 101 do { \ 102 if (0) \ 103 printk(level fmt, ##args); \ 104 } while (0) 105 #endif 106 107 /* TUN device flags */ 108 109 /* IFF_ATTACH_QUEUE is never stored in device flags, 110 * overload it to mean fasync when stored there. 111 */ 112 #define TUN_FASYNC IFF_ATTACH_QUEUE 113 /* High bits in flags field are unused. */ 114 #define TUN_VNET_LE 0x80000000 115 116 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \ 117 IFF_MULTI_QUEUE) 118 #define GOODCOPY_LEN 128 119 120 #define FLT_EXACT_COUNT 8 121 struct tap_filter { 122 unsigned int count; /* Number of addrs. Zero means disabled */ 123 u32 mask[2]; /* Mask of the hashed addrs */ 124 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 125 }; 126 127 /* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for 128 * the netdevice to be fit in one page. So we can make sure the success of 129 * memory allocation. TODO: increase the limit. */ 130 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES 131 #define MAX_TAP_FLOWS 4096 132 133 #define TUN_FLOW_EXPIRE (3 * HZ) 134 135 /* A tun_file connects an open character device to a tuntap netdevice. It 136 * also contains all socket related structures (except sock_fprog and tap_filter) 137 * to serve as one transmit queue for tuntap device. The sock_fprog and 138 * tap_filter were kept in tun_struct since they were used for filtering for the 139 * netdevice not for a specific queue (at least I didn't see the requirement for 140 * this). 141 * 142 * RCU usage: 143 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 144 * other can only be read while rcu_read_lock or rtnl_lock is held. 145 */ 146 struct tun_file { 147 struct sock sk; 148 struct socket socket; 149 struct socket_wq wq; 150 struct tun_struct __rcu *tun; 151 struct net *net; 152 struct fasync_struct *fasync; 153 /* only used for fasnyc */ 154 unsigned int flags; 155 union { 156 u16 queue_index; 157 unsigned int ifindex; 158 }; 159 struct list_head next; 160 struct tun_struct *detached; 161 }; 162 163 struct tun_flow_entry { 164 struct hlist_node hash_link; 165 struct rcu_head rcu; 166 struct tun_struct *tun; 167 168 u32 rxhash; 169 u32 rps_rxhash; 170 int queue_index; 171 unsigned long updated; 172 }; 173 174 #define TUN_NUM_FLOW_ENTRIES 1024 175 176 /* Since the socket were moved to tun_file, to preserve the behavior of persist 177 * device, socket filter, sndbuf and vnet header size were restore when the 178 * file were attached to a persist device. 179 */ 180 struct tun_struct { 181 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 182 unsigned int numqueues; 183 unsigned int flags; 184 kuid_t owner; 185 kgid_t group; 186 187 struct net_device *dev; 188 netdev_features_t set_features; 189 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 190 NETIF_F_TSO6) 191 192 int vnet_hdr_sz; 193 int sndbuf; 194 struct tap_filter txflt; 195 struct sock_fprog fprog; 196 /* protected by rtnl lock */ 197 bool filter_attached; 198 #ifdef TUN_DEBUG 199 int debug; 200 #endif 201 spinlock_t lock; 202 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 203 struct timer_list flow_gc_timer; 204 unsigned long ageing_time; 205 unsigned int numdisabled; 206 struct list_head disabled; 207 void *security; 208 u32 flow_count; 209 }; 210 211 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) 212 { 213 return __virtio16_to_cpu(tun->flags & TUN_VNET_LE, val); 214 } 215 216 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val) 217 { 218 return __cpu_to_virtio16(tun->flags & TUN_VNET_LE, val); 219 } 220 221 static inline u32 tun_hashfn(u32 rxhash) 222 { 223 return rxhash & 0x3ff; 224 } 225 226 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 227 { 228 struct tun_flow_entry *e; 229 230 hlist_for_each_entry_rcu(e, head, hash_link) { 231 if (e->rxhash == rxhash) 232 return e; 233 } 234 return NULL; 235 } 236 237 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 238 struct hlist_head *head, 239 u32 rxhash, u16 queue_index) 240 { 241 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 242 243 if (e) { 244 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 245 rxhash, queue_index); 246 e->updated = jiffies; 247 e->rxhash = rxhash; 248 e->rps_rxhash = 0; 249 e->queue_index = queue_index; 250 e->tun = tun; 251 hlist_add_head_rcu(&e->hash_link, head); 252 ++tun->flow_count; 253 } 254 return e; 255 } 256 257 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 258 { 259 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 260 e->rxhash, e->queue_index); 261 sock_rps_reset_flow_hash(e->rps_rxhash); 262 hlist_del_rcu(&e->hash_link); 263 kfree_rcu(e, rcu); 264 --tun->flow_count; 265 } 266 267 static void tun_flow_flush(struct tun_struct *tun) 268 { 269 int i; 270 271 spin_lock_bh(&tun->lock); 272 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 273 struct tun_flow_entry *e; 274 struct hlist_node *n; 275 276 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 277 tun_flow_delete(tun, e); 278 } 279 spin_unlock_bh(&tun->lock); 280 } 281 282 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 283 { 284 int i; 285 286 spin_lock_bh(&tun->lock); 287 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 288 struct tun_flow_entry *e; 289 struct hlist_node *n; 290 291 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 292 if (e->queue_index == queue_index) 293 tun_flow_delete(tun, e); 294 } 295 } 296 spin_unlock_bh(&tun->lock); 297 } 298 299 static void tun_flow_cleanup(unsigned long data) 300 { 301 struct tun_struct *tun = (struct tun_struct *)data; 302 unsigned long delay = tun->ageing_time; 303 unsigned long next_timer = jiffies + delay; 304 unsigned long count = 0; 305 int i; 306 307 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 308 309 spin_lock_bh(&tun->lock); 310 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 311 struct tun_flow_entry *e; 312 struct hlist_node *n; 313 314 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 315 unsigned long this_timer; 316 count++; 317 this_timer = e->updated + delay; 318 if (time_before_eq(this_timer, jiffies)) 319 tun_flow_delete(tun, e); 320 else if (time_before(this_timer, next_timer)) 321 next_timer = this_timer; 322 } 323 } 324 325 if (count) 326 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 327 spin_unlock_bh(&tun->lock); 328 } 329 330 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 331 struct tun_file *tfile) 332 { 333 struct hlist_head *head; 334 struct tun_flow_entry *e; 335 unsigned long delay = tun->ageing_time; 336 u16 queue_index = tfile->queue_index; 337 338 if (!rxhash) 339 return; 340 else 341 head = &tun->flows[tun_hashfn(rxhash)]; 342 343 rcu_read_lock(); 344 345 /* We may get a very small possibility of OOO during switching, not 346 * worth to optimize.*/ 347 if (tun->numqueues == 1 || tfile->detached) 348 goto unlock; 349 350 e = tun_flow_find(head, rxhash); 351 if (likely(e)) { 352 /* TODO: keep queueing to old queue until it's empty? */ 353 e->queue_index = queue_index; 354 e->updated = jiffies; 355 sock_rps_record_flow_hash(e->rps_rxhash); 356 } else { 357 spin_lock_bh(&tun->lock); 358 if (!tun_flow_find(head, rxhash) && 359 tun->flow_count < MAX_TAP_FLOWS) 360 tun_flow_create(tun, head, rxhash, queue_index); 361 362 if (!timer_pending(&tun->flow_gc_timer)) 363 mod_timer(&tun->flow_gc_timer, 364 round_jiffies_up(jiffies + delay)); 365 spin_unlock_bh(&tun->lock); 366 } 367 368 unlock: 369 rcu_read_unlock(); 370 } 371 372 /** 373 * Save the hash received in the stack receive path and update the 374 * flow_hash table accordingly. 375 */ 376 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 377 { 378 if (unlikely(e->rps_rxhash != hash)) { 379 sock_rps_reset_flow_hash(e->rps_rxhash); 380 e->rps_rxhash = hash; 381 } 382 } 383 384 /* We try to identify a flow through its rxhash first. The reason that 385 * we do not check rxq no. is because some cards(e.g 82599), chooses 386 * the rxq based on the txq where the last packet of the flow comes. As 387 * the userspace application move between processors, we may get a 388 * different rxq no. here. If we could not get rxhash, then we would 389 * hope the rxq no. may help here. 390 */ 391 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, 392 void *accel_priv, select_queue_fallback_t fallback) 393 { 394 struct tun_struct *tun = netdev_priv(dev); 395 struct tun_flow_entry *e; 396 u32 txq = 0; 397 u32 numqueues = 0; 398 399 rcu_read_lock(); 400 numqueues = ACCESS_ONCE(tun->numqueues); 401 402 txq = skb_get_hash(skb); 403 if (txq) { 404 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 405 if (e) { 406 tun_flow_save_rps_rxhash(e, txq); 407 txq = e->queue_index; 408 } else 409 /* use multiply and shift instead of expensive divide */ 410 txq = ((u64)txq * numqueues) >> 32; 411 } else if (likely(skb_rx_queue_recorded(skb))) { 412 txq = skb_get_rx_queue(skb); 413 while (unlikely(txq >= numqueues)) 414 txq -= numqueues; 415 } 416 417 rcu_read_unlock(); 418 return txq; 419 } 420 421 static inline bool tun_not_capable(struct tun_struct *tun) 422 { 423 const struct cred *cred = current_cred(); 424 struct net *net = dev_net(tun->dev); 425 426 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 427 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 428 !ns_capable(net->user_ns, CAP_NET_ADMIN); 429 } 430 431 static void tun_set_real_num_queues(struct tun_struct *tun) 432 { 433 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 434 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 435 } 436 437 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 438 { 439 tfile->detached = tun; 440 list_add_tail(&tfile->next, &tun->disabled); 441 ++tun->numdisabled; 442 } 443 444 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 445 { 446 struct tun_struct *tun = tfile->detached; 447 448 tfile->detached = NULL; 449 list_del_init(&tfile->next); 450 --tun->numdisabled; 451 return tun; 452 } 453 454 static void tun_queue_purge(struct tun_file *tfile) 455 { 456 skb_queue_purge(&tfile->sk.sk_receive_queue); 457 skb_queue_purge(&tfile->sk.sk_error_queue); 458 } 459 460 static void __tun_detach(struct tun_file *tfile, bool clean) 461 { 462 struct tun_file *ntfile; 463 struct tun_struct *tun; 464 465 tun = rtnl_dereference(tfile->tun); 466 467 if (tun && !tfile->detached) { 468 u16 index = tfile->queue_index; 469 BUG_ON(index >= tun->numqueues); 470 471 rcu_assign_pointer(tun->tfiles[index], 472 tun->tfiles[tun->numqueues - 1]); 473 ntfile = rtnl_dereference(tun->tfiles[index]); 474 ntfile->queue_index = index; 475 476 --tun->numqueues; 477 if (clean) { 478 RCU_INIT_POINTER(tfile->tun, NULL); 479 sock_put(&tfile->sk); 480 } else 481 tun_disable_queue(tun, tfile); 482 483 synchronize_net(); 484 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 485 /* Drop read queue */ 486 tun_queue_purge(tfile); 487 tun_set_real_num_queues(tun); 488 } else if (tfile->detached && clean) { 489 tun = tun_enable_queue(tfile); 490 sock_put(&tfile->sk); 491 } 492 493 if (clean) { 494 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 495 netif_carrier_off(tun->dev); 496 497 if (!(tun->flags & IFF_PERSIST) && 498 tun->dev->reg_state == NETREG_REGISTERED) 499 unregister_netdevice(tun->dev); 500 } 501 502 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 503 &tfile->socket.flags)); 504 sk_release_kernel(&tfile->sk); 505 } 506 } 507 508 static void tun_detach(struct tun_file *tfile, bool clean) 509 { 510 rtnl_lock(); 511 __tun_detach(tfile, clean); 512 rtnl_unlock(); 513 } 514 515 static void tun_detach_all(struct net_device *dev) 516 { 517 struct tun_struct *tun = netdev_priv(dev); 518 struct tun_file *tfile, *tmp; 519 int i, n = tun->numqueues; 520 521 for (i = 0; i < n; i++) { 522 tfile = rtnl_dereference(tun->tfiles[i]); 523 BUG_ON(!tfile); 524 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 525 RCU_INIT_POINTER(tfile->tun, NULL); 526 --tun->numqueues; 527 } 528 list_for_each_entry(tfile, &tun->disabled, next) { 529 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 530 RCU_INIT_POINTER(tfile->tun, NULL); 531 } 532 BUG_ON(tun->numqueues != 0); 533 534 synchronize_net(); 535 for (i = 0; i < n; i++) { 536 tfile = rtnl_dereference(tun->tfiles[i]); 537 /* Drop read queue */ 538 tun_queue_purge(tfile); 539 sock_put(&tfile->sk); 540 } 541 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 542 tun_enable_queue(tfile); 543 tun_queue_purge(tfile); 544 sock_put(&tfile->sk); 545 } 546 BUG_ON(tun->numdisabled != 0); 547 548 if (tun->flags & IFF_PERSIST) 549 module_put(THIS_MODULE); 550 } 551 552 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) 553 { 554 struct tun_file *tfile = file->private_data; 555 int err; 556 557 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 558 if (err < 0) 559 goto out; 560 561 err = -EINVAL; 562 if (rtnl_dereference(tfile->tun) && !tfile->detached) 563 goto out; 564 565 err = -EBUSY; 566 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1) 567 goto out; 568 569 err = -E2BIG; 570 if (!tfile->detached && 571 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 572 goto out; 573 574 err = 0; 575 576 /* Re-attach the filter to persist device */ 577 if (!skip_filter && (tun->filter_attached == true)) { 578 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 579 if (!err) 580 goto out; 581 } 582 tfile->queue_index = tun->numqueues; 583 rcu_assign_pointer(tfile->tun, tun); 584 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 585 tun->numqueues++; 586 587 if (tfile->detached) 588 tun_enable_queue(tfile); 589 else 590 sock_hold(&tfile->sk); 591 592 tun_set_real_num_queues(tun); 593 594 /* device is allowed to go away first, so no need to hold extra 595 * refcnt. 596 */ 597 598 out: 599 return err; 600 } 601 602 static struct tun_struct *__tun_get(struct tun_file *tfile) 603 { 604 struct tun_struct *tun; 605 606 rcu_read_lock(); 607 tun = rcu_dereference(tfile->tun); 608 if (tun) 609 dev_hold(tun->dev); 610 rcu_read_unlock(); 611 612 return tun; 613 } 614 615 static struct tun_struct *tun_get(struct file *file) 616 { 617 return __tun_get(file->private_data); 618 } 619 620 static void tun_put(struct tun_struct *tun) 621 { 622 dev_put(tun->dev); 623 } 624 625 /* TAP filtering */ 626 static void addr_hash_set(u32 *mask, const u8 *addr) 627 { 628 int n = ether_crc(ETH_ALEN, addr) >> 26; 629 mask[n >> 5] |= (1 << (n & 31)); 630 } 631 632 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 633 { 634 int n = ether_crc(ETH_ALEN, addr) >> 26; 635 return mask[n >> 5] & (1 << (n & 31)); 636 } 637 638 static int update_filter(struct tap_filter *filter, void __user *arg) 639 { 640 struct { u8 u[ETH_ALEN]; } *addr; 641 struct tun_filter uf; 642 int err, alen, n, nexact; 643 644 if (copy_from_user(&uf, arg, sizeof(uf))) 645 return -EFAULT; 646 647 if (!uf.count) { 648 /* Disabled */ 649 filter->count = 0; 650 return 0; 651 } 652 653 alen = ETH_ALEN * uf.count; 654 addr = kmalloc(alen, GFP_KERNEL); 655 if (!addr) 656 return -ENOMEM; 657 658 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 659 err = -EFAULT; 660 goto done; 661 } 662 663 /* The filter is updated without holding any locks. Which is 664 * perfectly safe. We disable it first and in the worst 665 * case we'll accept a few undesired packets. */ 666 filter->count = 0; 667 wmb(); 668 669 /* Use first set of addresses as an exact filter */ 670 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 671 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 672 673 nexact = n; 674 675 /* Remaining multicast addresses are hashed, 676 * unicast will leave the filter disabled. */ 677 memset(filter->mask, 0, sizeof(filter->mask)); 678 for (; n < uf.count; n++) { 679 if (!is_multicast_ether_addr(addr[n].u)) { 680 err = 0; /* no filter */ 681 goto done; 682 } 683 addr_hash_set(filter->mask, addr[n].u); 684 } 685 686 /* For ALLMULTI just set the mask to all ones. 687 * This overrides the mask populated above. */ 688 if ((uf.flags & TUN_FLT_ALLMULTI)) 689 memset(filter->mask, ~0, sizeof(filter->mask)); 690 691 /* Now enable the filter */ 692 wmb(); 693 filter->count = nexact; 694 695 /* Return the number of exact filters */ 696 err = nexact; 697 698 done: 699 kfree(addr); 700 return err; 701 } 702 703 /* Returns: 0 - drop, !=0 - accept */ 704 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 705 { 706 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 707 * at this point. */ 708 struct ethhdr *eh = (struct ethhdr *) skb->data; 709 int i; 710 711 /* Exact match */ 712 for (i = 0; i < filter->count; i++) 713 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 714 return 1; 715 716 /* Inexact match (multicast only) */ 717 if (is_multicast_ether_addr(eh->h_dest)) 718 return addr_hash_test(filter->mask, eh->h_dest); 719 720 return 0; 721 } 722 723 /* 724 * Checks whether the packet is accepted or not. 725 * Returns: 0 - drop, !=0 - accept 726 */ 727 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 728 { 729 if (!filter->count) 730 return 1; 731 732 return run_filter(filter, skb); 733 } 734 735 /* Network device part of the driver */ 736 737 static const struct ethtool_ops tun_ethtool_ops; 738 739 /* Net device detach from fd. */ 740 static void tun_net_uninit(struct net_device *dev) 741 { 742 tun_detach_all(dev); 743 } 744 745 /* Net device open. */ 746 static int tun_net_open(struct net_device *dev) 747 { 748 netif_tx_start_all_queues(dev); 749 return 0; 750 } 751 752 /* Net device close. */ 753 static int tun_net_close(struct net_device *dev) 754 { 755 netif_tx_stop_all_queues(dev); 756 return 0; 757 } 758 759 /* Net device start xmit */ 760 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 761 { 762 struct tun_struct *tun = netdev_priv(dev); 763 int txq = skb->queue_mapping; 764 struct tun_file *tfile; 765 u32 numqueues = 0; 766 767 rcu_read_lock(); 768 tfile = rcu_dereference(tun->tfiles[txq]); 769 numqueues = ACCESS_ONCE(tun->numqueues); 770 771 /* Drop packet if interface is not attached */ 772 if (txq >= numqueues) 773 goto drop; 774 775 if (numqueues == 1) { 776 /* Select queue was not called for the skbuff, so we extract the 777 * RPS hash and save it into the flow_table here. 778 */ 779 __u32 rxhash; 780 781 rxhash = skb_get_hash(skb); 782 if (rxhash) { 783 struct tun_flow_entry *e; 784 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], 785 rxhash); 786 if (e) 787 tun_flow_save_rps_rxhash(e, rxhash); 788 } 789 } 790 791 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 792 793 BUG_ON(!tfile); 794 795 /* Drop if the filter does not like it. 796 * This is a noop if the filter is disabled. 797 * Filter can be enabled only for the TAP devices. */ 798 if (!check_filter(&tun->txflt, skb)) 799 goto drop; 800 801 if (tfile->socket.sk->sk_filter && 802 sk_filter(tfile->socket.sk, skb)) 803 goto drop; 804 805 /* Limit the number of packets queued by dividing txq length with the 806 * number of queues. 807 */ 808 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues 809 >= dev->tx_queue_len) 810 goto drop; 811 812 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 813 goto drop; 814 815 if (skb->sk) { 816 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags); 817 sw_tx_timestamp(skb); 818 } 819 820 /* Orphan the skb - required as we might hang on to it 821 * for indefinite time. 822 */ 823 skb_orphan(skb); 824 825 nf_reset(skb); 826 827 /* Enqueue packet */ 828 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 829 830 /* Notify and wake up reader process */ 831 if (tfile->flags & TUN_FASYNC) 832 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 833 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 834 835 rcu_read_unlock(); 836 return NETDEV_TX_OK; 837 838 drop: 839 dev->stats.tx_dropped++; 840 skb_tx_error(skb); 841 kfree_skb(skb); 842 rcu_read_unlock(); 843 return NET_XMIT_DROP; 844 } 845 846 static void tun_net_mclist(struct net_device *dev) 847 { 848 /* 849 * This callback is supposed to deal with mc filter in 850 * _rx_ path and has nothing to do with the _tx_ path. 851 * In rx path we always accept everything userspace gives us. 852 */ 853 } 854 855 #define MIN_MTU 68 856 #define MAX_MTU 65535 857 858 static int 859 tun_net_change_mtu(struct net_device *dev, int new_mtu) 860 { 861 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 862 return -EINVAL; 863 dev->mtu = new_mtu; 864 return 0; 865 } 866 867 static netdev_features_t tun_net_fix_features(struct net_device *dev, 868 netdev_features_t features) 869 { 870 struct tun_struct *tun = netdev_priv(dev); 871 872 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 873 } 874 #ifdef CONFIG_NET_POLL_CONTROLLER 875 static void tun_poll_controller(struct net_device *dev) 876 { 877 /* 878 * Tun only receives frames when: 879 * 1) the char device endpoint gets data from user space 880 * 2) the tun socket gets a sendmsg call from user space 881 * Since both of those are synchronous operations, we are guaranteed 882 * never to have pending data when we poll for it 883 * so there is nothing to do here but return. 884 * We need this though so netpoll recognizes us as an interface that 885 * supports polling, which enables bridge devices in virt setups to 886 * still use netconsole 887 */ 888 return; 889 } 890 #endif 891 static const struct net_device_ops tun_netdev_ops = { 892 .ndo_uninit = tun_net_uninit, 893 .ndo_open = tun_net_open, 894 .ndo_stop = tun_net_close, 895 .ndo_start_xmit = tun_net_xmit, 896 .ndo_change_mtu = tun_net_change_mtu, 897 .ndo_fix_features = tun_net_fix_features, 898 .ndo_select_queue = tun_select_queue, 899 #ifdef CONFIG_NET_POLL_CONTROLLER 900 .ndo_poll_controller = tun_poll_controller, 901 #endif 902 }; 903 904 static const struct net_device_ops tap_netdev_ops = { 905 .ndo_uninit = tun_net_uninit, 906 .ndo_open = tun_net_open, 907 .ndo_stop = tun_net_close, 908 .ndo_start_xmit = tun_net_xmit, 909 .ndo_change_mtu = tun_net_change_mtu, 910 .ndo_fix_features = tun_net_fix_features, 911 .ndo_set_rx_mode = tun_net_mclist, 912 .ndo_set_mac_address = eth_mac_addr, 913 .ndo_validate_addr = eth_validate_addr, 914 .ndo_select_queue = tun_select_queue, 915 #ifdef CONFIG_NET_POLL_CONTROLLER 916 .ndo_poll_controller = tun_poll_controller, 917 #endif 918 }; 919 920 static void tun_flow_init(struct tun_struct *tun) 921 { 922 int i; 923 924 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 925 INIT_HLIST_HEAD(&tun->flows[i]); 926 927 tun->ageing_time = TUN_FLOW_EXPIRE; 928 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 929 mod_timer(&tun->flow_gc_timer, 930 round_jiffies_up(jiffies + tun->ageing_time)); 931 } 932 933 static void tun_flow_uninit(struct tun_struct *tun) 934 { 935 del_timer_sync(&tun->flow_gc_timer); 936 tun_flow_flush(tun); 937 } 938 939 /* Initialize net device. */ 940 static void tun_net_init(struct net_device *dev) 941 { 942 struct tun_struct *tun = netdev_priv(dev); 943 944 switch (tun->flags & TUN_TYPE_MASK) { 945 case IFF_TUN: 946 dev->netdev_ops = &tun_netdev_ops; 947 948 /* Point-to-Point TUN Device */ 949 dev->hard_header_len = 0; 950 dev->addr_len = 0; 951 dev->mtu = 1500; 952 953 /* Zero header length */ 954 dev->type = ARPHRD_NONE; 955 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 956 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 957 break; 958 959 case IFF_TAP: 960 dev->netdev_ops = &tap_netdev_ops; 961 /* Ethernet TAP Device */ 962 ether_setup(dev); 963 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 964 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 965 966 eth_hw_addr_random(dev); 967 968 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 969 break; 970 } 971 } 972 973 /* Character device part */ 974 975 /* Poll */ 976 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 977 { 978 struct tun_file *tfile = file->private_data; 979 struct tun_struct *tun = __tun_get(tfile); 980 struct sock *sk; 981 unsigned int mask = 0; 982 983 if (!tun) 984 return POLLERR; 985 986 sk = tfile->socket.sk; 987 988 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 989 990 poll_wait(file, sk_sleep(sk), wait); 991 992 if (!skb_queue_empty(&sk->sk_receive_queue)) 993 mask |= POLLIN | POLLRDNORM; 994 995 if (sock_writeable(sk) || 996 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 997 sock_writeable(sk))) 998 mask |= POLLOUT | POLLWRNORM; 999 1000 if (tun->dev->reg_state != NETREG_REGISTERED) 1001 mask = POLLERR; 1002 1003 tun_put(tun); 1004 return mask; 1005 } 1006 1007 /* prepad is the amount to reserve at front. len is length after that. 1008 * linear is a hint as to how much to copy (usually headers). */ 1009 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 1010 size_t prepad, size_t len, 1011 size_t linear, int noblock) 1012 { 1013 struct sock *sk = tfile->socket.sk; 1014 struct sk_buff *skb; 1015 int err; 1016 1017 /* Under a page? Don't bother with paged skb. */ 1018 if (prepad + len < PAGE_SIZE || !linear) 1019 linear = len; 1020 1021 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 1022 &err, 0); 1023 if (!skb) 1024 return ERR_PTR(err); 1025 1026 skb_reserve(skb, prepad); 1027 skb_put(skb, linear); 1028 skb->data_len = len - linear; 1029 skb->len += len - linear; 1030 1031 return skb; 1032 } 1033 1034 /* Get packet from user space buffer */ 1035 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1036 void *msg_control, struct iov_iter *from, 1037 int noblock) 1038 { 1039 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1040 struct sk_buff *skb; 1041 size_t total_len = iov_iter_count(from); 1042 size_t len = total_len, align = NET_SKB_PAD, linear; 1043 struct virtio_net_hdr gso = { 0 }; 1044 int good_linear; 1045 int copylen; 1046 bool zerocopy = false; 1047 int err; 1048 u32 rxhash; 1049 ssize_t n; 1050 1051 if (!(tun->flags & IFF_NO_PI)) { 1052 if (len < sizeof(pi)) 1053 return -EINVAL; 1054 len -= sizeof(pi); 1055 1056 n = copy_from_iter(&pi, sizeof(pi), from); 1057 if (n != sizeof(pi)) 1058 return -EFAULT; 1059 } 1060 1061 if (tun->flags & IFF_VNET_HDR) { 1062 if (len < tun->vnet_hdr_sz) 1063 return -EINVAL; 1064 len -= tun->vnet_hdr_sz; 1065 1066 n = copy_from_iter(&gso, sizeof(gso), from); 1067 if (n != sizeof(gso)) 1068 return -EFAULT; 1069 1070 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1071 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len)) 1072 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2); 1073 1074 if (tun16_to_cpu(tun, gso.hdr_len) > len) 1075 return -EINVAL; 1076 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso)); 1077 } 1078 1079 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) { 1080 align += NET_IP_ALIGN; 1081 if (unlikely(len < ETH_HLEN || 1082 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN))) 1083 return -EINVAL; 1084 } 1085 1086 good_linear = SKB_MAX_HEAD(align); 1087 1088 if (msg_control) { 1089 struct iov_iter i = *from; 1090 1091 /* There are 256 bytes to be copied in skb, so there is 1092 * enough room for skb expand head in case it is used. 1093 * The rest of the buffer is mapped from userspace. 1094 */ 1095 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN; 1096 if (copylen > good_linear) 1097 copylen = good_linear; 1098 linear = copylen; 1099 iov_iter_advance(&i, copylen); 1100 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS) 1101 zerocopy = true; 1102 } 1103 1104 if (!zerocopy) { 1105 copylen = len; 1106 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear) 1107 linear = good_linear; 1108 else 1109 linear = tun16_to_cpu(tun, gso.hdr_len); 1110 } 1111 1112 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1113 if (IS_ERR(skb)) { 1114 if (PTR_ERR(skb) != -EAGAIN) 1115 tun->dev->stats.rx_dropped++; 1116 return PTR_ERR(skb); 1117 } 1118 1119 if (zerocopy) 1120 err = zerocopy_sg_from_iter(skb, from); 1121 else { 1122 err = skb_copy_datagram_from_iter(skb, 0, from, len); 1123 if (!err && msg_control) { 1124 struct ubuf_info *uarg = msg_control; 1125 uarg->callback(uarg, false); 1126 } 1127 } 1128 1129 if (err) { 1130 tun->dev->stats.rx_dropped++; 1131 kfree_skb(skb); 1132 return -EFAULT; 1133 } 1134 1135 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1136 if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start), 1137 tun16_to_cpu(tun, gso.csum_offset))) { 1138 tun->dev->stats.rx_frame_errors++; 1139 kfree_skb(skb); 1140 return -EINVAL; 1141 } 1142 } 1143 1144 switch (tun->flags & TUN_TYPE_MASK) { 1145 case IFF_TUN: 1146 if (tun->flags & IFF_NO_PI) { 1147 switch (skb->data[0] & 0xf0) { 1148 case 0x40: 1149 pi.proto = htons(ETH_P_IP); 1150 break; 1151 case 0x60: 1152 pi.proto = htons(ETH_P_IPV6); 1153 break; 1154 default: 1155 tun->dev->stats.rx_dropped++; 1156 kfree_skb(skb); 1157 return -EINVAL; 1158 } 1159 } 1160 1161 skb_reset_mac_header(skb); 1162 skb->protocol = pi.proto; 1163 skb->dev = tun->dev; 1164 break; 1165 case IFF_TAP: 1166 skb->protocol = eth_type_trans(skb, tun->dev); 1167 break; 1168 } 1169 1170 skb_reset_network_header(skb); 1171 1172 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1173 pr_debug("GSO!\n"); 1174 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1175 case VIRTIO_NET_HDR_GSO_TCPV4: 1176 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1177 break; 1178 case VIRTIO_NET_HDR_GSO_TCPV6: 1179 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1180 break; 1181 case VIRTIO_NET_HDR_GSO_UDP: 1182 { 1183 static bool warned; 1184 1185 if (!warned) { 1186 warned = true; 1187 netdev_warn(tun->dev, 1188 "%s: using disabled UFO feature; please fix this program\n", 1189 current->comm); 1190 } 1191 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1192 if (skb->protocol == htons(ETH_P_IPV6)) 1193 ipv6_proxy_select_ident(skb); 1194 break; 1195 } 1196 default: 1197 tun->dev->stats.rx_frame_errors++; 1198 kfree_skb(skb); 1199 return -EINVAL; 1200 } 1201 1202 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1203 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1204 1205 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size); 1206 if (skb_shinfo(skb)->gso_size == 0) { 1207 tun->dev->stats.rx_frame_errors++; 1208 kfree_skb(skb); 1209 return -EINVAL; 1210 } 1211 1212 /* Header must be checked, and gso_segs computed. */ 1213 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1214 skb_shinfo(skb)->gso_segs = 0; 1215 } 1216 1217 /* copy skb_ubuf_info for callback when skb has no error */ 1218 if (zerocopy) { 1219 skb_shinfo(skb)->destructor_arg = msg_control; 1220 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1221 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1222 } 1223 1224 skb_probe_transport_header(skb, 0); 1225 1226 rxhash = skb_get_hash(skb); 1227 netif_rx_ni(skb); 1228 1229 tun->dev->stats.rx_packets++; 1230 tun->dev->stats.rx_bytes += len; 1231 1232 tun_flow_update(tun, rxhash, tfile); 1233 return total_len; 1234 } 1235 1236 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from) 1237 { 1238 struct file *file = iocb->ki_filp; 1239 struct tun_struct *tun = tun_get(file); 1240 struct tun_file *tfile = file->private_data; 1241 ssize_t result; 1242 1243 if (!tun) 1244 return -EBADFD; 1245 1246 result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK); 1247 1248 tun_put(tun); 1249 return result; 1250 } 1251 1252 /* Put packet to the user space buffer */ 1253 static ssize_t tun_put_user(struct tun_struct *tun, 1254 struct tun_file *tfile, 1255 struct sk_buff *skb, 1256 struct iov_iter *iter) 1257 { 1258 struct tun_pi pi = { 0, skb->protocol }; 1259 ssize_t total; 1260 int vlan_offset = 0; 1261 int vlan_hlen = 0; 1262 int vnet_hdr_sz = 0; 1263 1264 if (vlan_tx_tag_present(skb)) 1265 vlan_hlen = VLAN_HLEN; 1266 1267 if (tun->flags & IFF_VNET_HDR) 1268 vnet_hdr_sz = tun->vnet_hdr_sz; 1269 1270 total = skb->len + vlan_hlen + vnet_hdr_sz; 1271 1272 if (!(tun->flags & IFF_NO_PI)) { 1273 if (iov_iter_count(iter) < sizeof(pi)) 1274 return -EINVAL; 1275 1276 total += sizeof(pi); 1277 if (iov_iter_count(iter) < total) { 1278 /* Packet will be striped */ 1279 pi.flags |= TUN_PKT_STRIP; 1280 } 1281 1282 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi)) 1283 return -EFAULT; 1284 } 1285 1286 if (vnet_hdr_sz) { 1287 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1288 if (iov_iter_count(iter) < vnet_hdr_sz) 1289 return -EINVAL; 1290 1291 if (skb_is_gso(skb)) { 1292 struct skb_shared_info *sinfo = skb_shinfo(skb); 1293 1294 /* This is a hint as to how much should be linear. */ 1295 gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb)); 1296 gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size); 1297 if (sinfo->gso_type & SKB_GSO_TCPV4) 1298 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1299 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1300 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1301 else { 1302 pr_err("unexpected GSO type: " 1303 "0x%x, gso_size %d, hdr_len %d\n", 1304 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size), 1305 tun16_to_cpu(tun, gso.hdr_len)); 1306 print_hex_dump(KERN_ERR, "tun: ", 1307 DUMP_PREFIX_NONE, 1308 16, 1, skb->head, 1309 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true); 1310 WARN_ON_ONCE(1); 1311 return -EINVAL; 1312 } 1313 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1314 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1315 } else 1316 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1317 1318 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1319 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1320 gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) + 1321 vlan_hlen); 1322 gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset); 1323 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1324 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1325 } /* else everything is zero */ 1326 1327 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso)) 1328 return -EFAULT; 1329 1330 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso)); 1331 } 1332 1333 if (vlan_hlen) { 1334 int ret; 1335 struct { 1336 __be16 h_vlan_proto; 1337 __be16 h_vlan_TCI; 1338 } veth; 1339 1340 veth.h_vlan_proto = skb->vlan_proto; 1341 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 1342 1343 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1344 1345 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset); 1346 if (ret || !iov_iter_count(iter)) 1347 goto done; 1348 1349 ret = copy_to_iter(&veth, sizeof(veth), iter); 1350 if (ret != sizeof(veth) || !iov_iter_count(iter)) 1351 goto done; 1352 } 1353 1354 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset); 1355 1356 done: 1357 tun->dev->stats.tx_packets++; 1358 tun->dev->stats.tx_bytes += skb->len + vlan_hlen; 1359 1360 return total; 1361 } 1362 1363 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1364 struct iov_iter *to, 1365 int noblock) 1366 { 1367 struct sk_buff *skb; 1368 ssize_t ret; 1369 int peeked, err, off = 0; 1370 1371 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1372 1373 if (!iov_iter_count(to)) 1374 return 0; 1375 1376 if (tun->dev->reg_state != NETREG_REGISTERED) 1377 return -EIO; 1378 1379 /* Read frames from queue */ 1380 skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0, 1381 &peeked, &off, &err); 1382 if (!skb) 1383 return 0; 1384 1385 ret = tun_put_user(tun, tfile, skb, to); 1386 if (unlikely(ret < 0)) 1387 kfree_skb(skb); 1388 else 1389 consume_skb(skb); 1390 1391 return ret; 1392 } 1393 1394 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1395 { 1396 struct file *file = iocb->ki_filp; 1397 struct tun_file *tfile = file->private_data; 1398 struct tun_struct *tun = __tun_get(tfile); 1399 ssize_t len = iov_iter_count(to), ret; 1400 1401 if (!tun) 1402 return -EBADFD; 1403 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK); 1404 ret = min_t(ssize_t, ret, len); 1405 if (ret > 0) 1406 iocb->ki_pos = ret; 1407 tun_put(tun); 1408 return ret; 1409 } 1410 1411 static void tun_free_netdev(struct net_device *dev) 1412 { 1413 struct tun_struct *tun = netdev_priv(dev); 1414 1415 BUG_ON(!(list_empty(&tun->disabled))); 1416 tun_flow_uninit(tun); 1417 security_tun_dev_free_security(tun->security); 1418 free_netdev(dev); 1419 } 1420 1421 static void tun_setup(struct net_device *dev) 1422 { 1423 struct tun_struct *tun = netdev_priv(dev); 1424 1425 tun->owner = INVALID_UID; 1426 tun->group = INVALID_GID; 1427 1428 dev->ethtool_ops = &tun_ethtool_ops; 1429 dev->destructor = tun_free_netdev; 1430 } 1431 1432 /* Trivial set of netlink ops to allow deleting tun or tap 1433 * device with netlink. 1434 */ 1435 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1436 { 1437 return -EINVAL; 1438 } 1439 1440 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1441 .kind = DRV_NAME, 1442 .priv_size = sizeof(struct tun_struct), 1443 .setup = tun_setup, 1444 .validate = tun_validate, 1445 }; 1446 1447 static void tun_sock_write_space(struct sock *sk) 1448 { 1449 struct tun_file *tfile; 1450 wait_queue_head_t *wqueue; 1451 1452 if (!sock_writeable(sk)) 1453 return; 1454 1455 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1456 return; 1457 1458 wqueue = sk_sleep(sk); 1459 if (wqueue && waitqueue_active(wqueue)) 1460 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1461 POLLWRNORM | POLLWRBAND); 1462 1463 tfile = container_of(sk, struct tun_file, sk); 1464 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1465 } 1466 1467 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1468 struct msghdr *m, size_t total_len) 1469 { 1470 int ret; 1471 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1472 struct tun_struct *tun = __tun_get(tfile); 1473 1474 if (!tun) 1475 return -EBADFD; 1476 1477 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter, 1478 m->msg_flags & MSG_DONTWAIT); 1479 tun_put(tun); 1480 return ret; 1481 } 1482 1483 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1484 struct msghdr *m, size_t total_len, 1485 int flags) 1486 { 1487 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1488 struct tun_struct *tun = __tun_get(tfile); 1489 int ret; 1490 1491 if (!tun) 1492 return -EBADFD; 1493 1494 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1495 ret = -EINVAL; 1496 goto out; 1497 } 1498 if (flags & MSG_ERRQUEUE) { 1499 ret = sock_recv_errqueue(sock->sk, m, total_len, 1500 SOL_PACKET, TUN_TX_TIMESTAMP); 1501 goto out; 1502 } 1503 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT); 1504 if (ret > total_len) { 1505 m->msg_flags |= MSG_TRUNC; 1506 ret = flags & MSG_TRUNC ? ret : total_len; 1507 } 1508 out: 1509 tun_put(tun); 1510 return ret; 1511 } 1512 1513 static int tun_release(struct socket *sock) 1514 { 1515 if (sock->sk) 1516 sock_put(sock->sk); 1517 return 0; 1518 } 1519 1520 /* Ops structure to mimic raw sockets with tun */ 1521 static const struct proto_ops tun_socket_ops = { 1522 .sendmsg = tun_sendmsg, 1523 .recvmsg = tun_recvmsg, 1524 .release = tun_release, 1525 }; 1526 1527 static struct proto tun_proto = { 1528 .name = "tun", 1529 .owner = THIS_MODULE, 1530 .obj_size = sizeof(struct tun_file), 1531 }; 1532 1533 static int tun_flags(struct tun_struct *tun) 1534 { 1535 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP); 1536 } 1537 1538 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1539 char *buf) 1540 { 1541 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1542 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1543 } 1544 1545 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1546 char *buf) 1547 { 1548 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1549 return uid_valid(tun->owner)? 1550 sprintf(buf, "%u\n", 1551 from_kuid_munged(current_user_ns(), tun->owner)): 1552 sprintf(buf, "-1\n"); 1553 } 1554 1555 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1556 char *buf) 1557 { 1558 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1559 return gid_valid(tun->group) ? 1560 sprintf(buf, "%u\n", 1561 from_kgid_munged(current_user_ns(), tun->group)): 1562 sprintf(buf, "-1\n"); 1563 } 1564 1565 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1566 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1567 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1568 1569 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1570 { 1571 struct tun_struct *tun; 1572 struct tun_file *tfile = file->private_data; 1573 struct net_device *dev; 1574 int err; 1575 1576 if (tfile->detached) 1577 return -EINVAL; 1578 1579 dev = __dev_get_by_name(net, ifr->ifr_name); 1580 if (dev) { 1581 if (ifr->ifr_flags & IFF_TUN_EXCL) 1582 return -EBUSY; 1583 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1584 tun = netdev_priv(dev); 1585 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1586 tun = netdev_priv(dev); 1587 else 1588 return -EINVAL; 1589 1590 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1591 !!(tun->flags & IFF_MULTI_QUEUE)) 1592 return -EINVAL; 1593 1594 if (tun_not_capable(tun)) 1595 return -EPERM; 1596 err = security_tun_dev_open(tun->security); 1597 if (err < 0) 1598 return err; 1599 1600 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1601 if (err < 0) 1602 return err; 1603 1604 if (tun->flags & IFF_MULTI_QUEUE && 1605 (tun->numqueues + tun->numdisabled > 1)) { 1606 /* One or more queue has already been attached, no need 1607 * to initialize the device again. 1608 */ 1609 return 0; 1610 } 1611 } 1612 else { 1613 char *name; 1614 unsigned long flags = 0; 1615 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1616 MAX_TAP_QUEUES : 1; 1617 1618 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1619 return -EPERM; 1620 err = security_tun_dev_create(); 1621 if (err < 0) 1622 return err; 1623 1624 /* Set dev type */ 1625 if (ifr->ifr_flags & IFF_TUN) { 1626 /* TUN device */ 1627 flags |= IFF_TUN; 1628 name = "tun%d"; 1629 } else if (ifr->ifr_flags & IFF_TAP) { 1630 /* TAP device */ 1631 flags |= IFF_TAP; 1632 name = "tap%d"; 1633 } else 1634 return -EINVAL; 1635 1636 if (*ifr->ifr_name) 1637 name = ifr->ifr_name; 1638 1639 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1640 NET_NAME_UNKNOWN, tun_setup, queues, 1641 queues); 1642 1643 if (!dev) 1644 return -ENOMEM; 1645 1646 dev_net_set(dev, net); 1647 dev->rtnl_link_ops = &tun_link_ops; 1648 dev->ifindex = tfile->ifindex; 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 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1686 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1687 device_create_file(&tun->dev->dev, &dev_attr_group)) 1688 pr_err("Failed to create tun sysfs files\n"); 1689 } 1690 1691 netif_carrier_on(tun->dev); 1692 1693 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1694 1695 tun->flags = (tun->flags & ~TUN_FEATURES) | 1696 (ifr->ifr_flags & TUN_FEATURES); 1697 1698 /* Make sure persistent devices do not get stuck in 1699 * xoff state. 1700 */ 1701 if (netif_running(tun->dev)) 1702 netif_tx_wake_all_queues(tun->dev); 1703 1704 strcpy(ifr->ifr_name, tun->dev->name); 1705 return 0; 1706 1707 err_detach: 1708 tun_detach_all(dev); 1709 err_free_flow: 1710 tun_flow_uninit(tun); 1711 security_tun_dev_free_security(tun->security); 1712 err_free_dev: 1713 free_netdev(dev); 1714 return err; 1715 } 1716 1717 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1718 struct ifreq *ifr) 1719 { 1720 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1721 1722 strcpy(ifr->ifr_name, tun->dev->name); 1723 1724 ifr->ifr_flags = tun_flags(tun); 1725 1726 } 1727 1728 /* This is like a cut-down ethtool ops, except done via tun fd so no 1729 * privs required. */ 1730 static int set_offload(struct tun_struct *tun, unsigned long arg) 1731 { 1732 netdev_features_t features = 0; 1733 1734 if (arg & TUN_F_CSUM) { 1735 features |= NETIF_F_HW_CSUM; 1736 arg &= ~TUN_F_CSUM; 1737 1738 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1739 if (arg & TUN_F_TSO_ECN) { 1740 features |= NETIF_F_TSO_ECN; 1741 arg &= ~TUN_F_TSO_ECN; 1742 } 1743 if (arg & TUN_F_TSO4) 1744 features |= NETIF_F_TSO; 1745 if (arg & TUN_F_TSO6) 1746 features |= NETIF_F_TSO6; 1747 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 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 = new_sync_read, 2233 .write = new_sync_write, 2234 .read_iter = tun_chr_read_iter, 2235 .write_iter = tun_chr_write_iter, 2236 .poll = tun_chr_poll, 2237 .unlocked_ioctl = tun_chr_ioctl, 2238 #ifdef CONFIG_COMPAT 2239 .compat_ioctl = tun_chr_compat_ioctl, 2240 #endif 2241 .open = tun_chr_open, 2242 .release = tun_chr_close, 2243 .fasync = tun_chr_fasync, 2244 #ifdef CONFIG_PROC_FS 2245 .show_fdinfo = tun_chr_show_fdinfo, 2246 #endif 2247 }; 2248 2249 static struct miscdevice tun_miscdev = { 2250 .minor = TUN_MINOR, 2251 .name = "tun", 2252 .nodename = "net/tun", 2253 .fops = &tun_fops, 2254 }; 2255 2256 /* ethtool interface */ 2257 2258 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2259 { 2260 cmd->supported = 0; 2261 cmd->advertising = 0; 2262 ethtool_cmd_speed_set(cmd, SPEED_10); 2263 cmd->duplex = DUPLEX_FULL; 2264 cmd->port = PORT_TP; 2265 cmd->phy_address = 0; 2266 cmd->transceiver = XCVR_INTERNAL; 2267 cmd->autoneg = AUTONEG_DISABLE; 2268 cmd->maxtxpkt = 0; 2269 cmd->maxrxpkt = 0; 2270 return 0; 2271 } 2272 2273 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2274 { 2275 struct tun_struct *tun = netdev_priv(dev); 2276 2277 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2278 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2279 2280 switch (tun->flags & TUN_TYPE_MASK) { 2281 case IFF_TUN: 2282 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2283 break; 2284 case IFF_TAP: 2285 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2286 break; 2287 } 2288 } 2289 2290 static u32 tun_get_msglevel(struct net_device *dev) 2291 { 2292 #ifdef TUN_DEBUG 2293 struct tun_struct *tun = netdev_priv(dev); 2294 return tun->debug; 2295 #else 2296 return -EOPNOTSUPP; 2297 #endif 2298 } 2299 2300 static void tun_set_msglevel(struct net_device *dev, u32 value) 2301 { 2302 #ifdef TUN_DEBUG 2303 struct tun_struct *tun = netdev_priv(dev); 2304 tun->debug = value; 2305 #endif 2306 } 2307 2308 static const struct ethtool_ops tun_ethtool_ops = { 2309 .get_settings = tun_get_settings, 2310 .get_drvinfo = tun_get_drvinfo, 2311 .get_msglevel = tun_get_msglevel, 2312 .set_msglevel = tun_set_msglevel, 2313 .get_link = ethtool_op_get_link, 2314 .get_ts_info = ethtool_op_get_ts_info, 2315 }; 2316 2317 2318 static int __init tun_init(void) 2319 { 2320 int ret = 0; 2321 2322 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2323 pr_info("%s\n", DRV_COPYRIGHT); 2324 2325 ret = rtnl_link_register(&tun_link_ops); 2326 if (ret) { 2327 pr_err("Can't register link_ops\n"); 2328 goto err_linkops; 2329 } 2330 2331 ret = misc_register(&tun_miscdev); 2332 if (ret) { 2333 pr_err("Can't register misc device %d\n", TUN_MINOR); 2334 goto err_misc; 2335 } 2336 return 0; 2337 err_misc: 2338 rtnl_link_unregister(&tun_link_ops); 2339 err_linkops: 2340 return ret; 2341 } 2342 2343 static void tun_cleanup(void) 2344 { 2345 misc_deregister(&tun_miscdev); 2346 rtnl_link_unregister(&tun_link_ops); 2347 } 2348 2349 /* Get an underlying socket object from tun file. Returns error unless file is 2350 * attached to a device. The returned object works like a packet socket, it 2351 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2352 * holding a reference to the file for as long as the socket is in use. */ 2353 struct socket *tun_get_socket(struct file *file) 2354 { 2355 struct tun_file *tfile; 2356 if (file->f_op != &tun_fops) 2357 return ERR_PTR(-EINVAL); 2358 tfile = file->private_data; 2359 if (!tfile) 2360 return ERR_PTR(-EBADFD); 2361 return &tfile->socket; 2362 } 2363 EXPORT_SYMBOL_GPL(tun_get_socket); 2364 2365 module_init(tun_init); 2366 module_exit(tun_cleanup); 2367 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2368 MODULE_AUTHOR(DRV_COPYRIGHT); 2369 MODULE_LICENSE("GPL"); 2370 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2371 MODULE_ALIAS("devname:net/tun"); 2372