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 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 112 113 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \ 114 IFF_VNET_LE | IFF_MULTI_QUEUE) 115 #define GOODCOPY_LEN 128 116 117 #define FLT_EXACT_COUNT 8 118 struct tap_filter { 119 unsigned int count; /* Number of addrs. Zero means disabled */ 120 u32 mask[2]; /* Mask of the hashed addrs */ 121 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 122 }; 123 124 /* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for 125 * the netdevice to be fit in one page. So we can make sure the success of 126 * memory allocation. TODO: increase the limit. */ 127 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES 128 #define MAX_TAP_FLOWS 4096 129 130 #define TUN_FLOW_EXPIRE (3 * HZ) 131 132 /* A tun_file connects an open character device to a tuntap netdevice. It 133 * also contains all socket related structures (except sock_fprog and tap_filter) 134 * to serve as one transmit queue for tuntap device. The sock_fprog and 135 * tap_filter were kept in tun_struct since they were used for filtering for the 136 * netdevice not for a specific queue (at least I didn't see the requirement for 137 * this). 138 * 139 * RCU usage: 140 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 141 * other can only be read while rcu_read_lock or rtnl_lock is held. 142 */ 143 struct tun_file { 144 struct sock sk; 145 struct socket socket; 146 struct socket_wq wq; 147 struct tun_struct __rcu *tun; 148 struct net *net; 149 struct fasync_struct *fasync; 150 /* only used for fasnyc */ 151 unsigned int flags; 152 union { 153 u16 queue_index; 154 unsigned int ifindex; 155 }; 156 struct list_head next; 157 struct tun_struct *detached; 158 }; 159 160 struct tun_flow_entry { 161 struct hlist_node hash_link; 162 struct rcu_head rcu; 163 struct tun_struct *tun; 164 165 u32 rxhash; 166 u32 rps_rxhash; 167 int queue_index; 168 unsigned long updated; 169 }; 170 171 #define TUN_NUM_FLOW_ENTRIES 1024 172 173 /* Since the socket were moved to tun_file, to preserve the behavior of persist 174 * device, socket filter, sndbuf and vnet header size were restore when the 175 * file were attached to a persist device. 176 */ 177 struct tun_struct { 178 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 179 unsigned int numqueues; 180 unsigned int flags; 181 kuid_t owner; 182 kgid_t group; 183 184 struct net_device *dev; 185 netdev_features_t set_features; 186 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 187 NETIF_F_TSO6) 188 189 int vnet_hdr_sz; 190 int sndbuf; 191 struct tap_filter txflt; 192 struct sock_fprog fprog; 193 /* protected by rtnl lock */ 194 bool filter_attached; 195 #ifdef TUN_DEBUG 196 int debug; 197 #endif 198 spinlock_t lock; 199 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 200 struct timer_list flow_gc_timer; 201 unsigned long ageing_time; 202 unsigned int numdisabled; 203 struct list_head disabled; 204 void *security; 205 u32 flow_count; 206 }; 207 208 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) 209 { 210 return __virtio16_to_cpu(tun->flags & IFF_VNET_LE, val); 211 } 212 213 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val) 214 { 215 return __cpu_to_virtio16(tun->flags & IFF_VNET_LE, val); 216 } 217 218 static inline u32 tun_hashfn(u32 rxhash) 219 { 220 return rxhash & 0x3ff; 221 } 222 223 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 224 { 225 struct tun_flow_entry *e; 226 227 hlist_for_each_entry_rcu(e, head, hash_link) { 228 if (e->rxhash == rxhash) 229 return e; 230 } 231 return NULL; 232 } 233 234 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 235 struct hlist_head *head, 236 u32 rxhash, u16 queue_index) 237 { 238 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 239 240 if (e) { 241 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 242 rxhash, queue_index); 243 e->updated = jiffies; 244 e->rxhash = rxhash; 245 e->rps_rxhash = 0; 246 e->queue_index = queue_index; 247 e->tun = tun; 248 hlist_add_head_rcu(&e->hash_link, head); 249 ++tun->flow_count; 250 } 251 return e; 252 } 253 254 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 255 { 256 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 257 e->rxhash, e->queue_index); 258 sock_rps_reset_flow_hash(e->rps_rxhash); 259 hlist_del_rcu(&e->hash_link); 260 kfree_rcu(e, rcu); 261 --tun->flow_count; 262 } 263 264 static void tun_flow_flush(struct tun_struct *tun) 265 { 266 int i; 267 268 spin_lock_bh(&tun->lock); 269 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 270 struct tun_flow_entry *e; 271 struct hlist_node *n; 272 273 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 274 tun_flow_delete(tun, e); 275 } 276 spin_unlock_bh(&tun->lock); 277 } 278 279 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 280 { 281 int i; 282 283 spin_lock_bh(&tun->lock); 284 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 285 struct tun_flow_entry *e; 286 struct hlist_node *n; 287 288 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 289 if (e->queue_index == queue_index) 290 tun_flow_delete(tun, e); 291 } 292 } 293 spin_unlock_bh(&tun->lock); 294 } 295 296 static void tun_flow_cleanup(unsigned long data) 297 { 298 struct tun_struct *tun = (struct tun_struct *)data; 299 unsigned long delay = tun->ageing_time; 300 unsigned long next_timer = jiffies + delay; 301 unsigned long count = 0; 302 int i; 303 304 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 305 306 spin_lock_bh(&tun->lock); 307 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 308 struct tun_flow_entry *e; 309 struct hlist_node *n; 310 311 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 312 unsigned long this_timer; 313 count++; 314 this_timer = e->updated + delay; 315 if (time_before_eq(this_timer, jiffies)) 316 tun_flow_delete(tun, e); 317 else if (time_before(this_timer, next_timer)) 318 next_timer = this_timer; 319 } 320 } 321 322 if (count) 323 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 324 spin_unlock_bh(&tun->lock); 325 } 326 327 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 328 struct tun_file *tfile) 329 { 330 struct hlist_head *head; 331 struct tun_flow_entry *e; 332 unsigned long delay = tun->ageing_time; 333 u16 queue_index = tfile->queue_index; 334 335 if (!rxhash) 336 return; 337 else 338 head = &tun->flows[tun_hashfn(rxhash)]; 339 340 rcu_read_lock(); 341 342 /* We may get a very small possibility of OOO during switching, not 343 * worth to optimize.*/ 344 if (tun->numqueues == 1 || tfile->detached) 345 goto unlock; 346 347 e = tun_flow_find(head, rxhash); 348 if (likely(e)) { 349 /* TODO: keep queueing to old queue until it's empty? */ 350 e->queue_index = queue_index; 351 e->updated = jiffies; 352 sock_rps_record_flow_hash(e->rps_rxhash); 353 } else { 354 spin_lock_bh(&tun->lock); 355 if (!tun_flow_find(head, rxhash) && 356 tun->flow_count < MAX_TAP_FLOWS) 357 tun_flow_create(tun, head, rxhash, queue_index); 358 359 if (!timer_pending(&tun->flow_gc_timer)) 360 mod_timer(&tun->flow_gc_timer, 361 round_jiffies_up(jiffies + delay)); 362 spin_unlock_bh(&tun->lock); 363 } 364 365 unlock: 366 rcu_read_unlock(); 367 } 368 369 /** 370 * Save the hash received in the stack receive path and update the 371 * flow_hash table accordingly. 372 */ 373 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 374 { 375 if (unlikely(e->rps_rxhash != hash)) { 376 sock_rps_reset_flow_hash(e->rps_rxhash); 377 e->rps_rxhash = hash; 378 } 379 } 380 381 /* We try to identify a flow through its rxhash first. The reason that 382 * we do not check rxq no. is because some cards(e.g 82599), chooses 383 * the rxq based on the txq where the last packet of the flow comes. As 384 * the userspace application move between processors, we may get a 385 * different rxq no. here. If we could not get rxhash, then we would 386 * hope the rxq no. may help here. 387 */ 388 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, 389 void *accel_priv, select_queue_fallback_t fallback) 390 { 391 struct tun_struct *tun = netdev_priv(dev); 392 struct tun_flow_entry *e; 393 u32 txq = 0; 394 u32 numqueues = 0; 395 396 rcu_read_lock(); 397 numqueues = ACCESS_ONCE(tun->numqueues); 398 399 txq = skb_get_hash(skb); 400 if (txq) { 401 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 402 if (e) { 403 tun_flow_save_rps_rxhash(e, txq); 404 txq = e->queue_index; 405 } else 406 /* use multiply and shift instead of expensive divide */ 407 txq = ((u64)txq * numqueues) >> 32; 408 } else if (likely(skb_rx_queue_recorded(skb))) { 409 txq = skb_get_rx_queue(skb); 410 while (unlikely(txq >= numqueues)) 411 txq -= numqueues; 412 } 413 414 rcu_read_unlock(); 415 return txq; 416 } 417 418 static inline bool tun_not_capable(struct tun_struct *tun) 419 { 420 const struct cred *cred = current_cred(); 421 struct net *net = dev_net(tun->dev); 422 423 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 424 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 425 !ns_capable(net->user_ns, CAP_NET_ADMIN); 426 } 427 428 static void tun_set_real_num_queues(struct tun_struct *tun) 429 { 430 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 431 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 432 } 433 434 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 435 { 436 tfile->detached = tun; 437 list_add_tail(&tfile->next, &tun->disabled); 438 ++tun->numdisabled; 439 } 440 441 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 442 { 443 struct tun_struct *tun = tfile->detached; 444 445 tfile->detached = NULL; 446 list_del_init(&tfile->next); 447 --tun->numdisabled; 448 return tun; 449 } 450 451 static void tun_queue_purge(struct tun_file *tfile) 452 { 453 skb_queue_purge(&tfile->sk.sk_receive_queue); 454 skb_queue_purge(&tfile->sk.sk_error_queue); 455 } 456 457 static void __tun_detach(struct tun_file *tfile, bool clean) 458 { 459 struct tun_file *ntfile; 460 struct tun_struct *tun; 461 462 tun = rtnl_dereference(tfile->tun); 463 464 if (tun && !tfile->detached) { 465 u16 index = tfile->queue_index; 466 BUG_ON(index >= tun->numqueues); 467 468 rcu_assign_pointer(tun->tfiles[index], 469 tun->tfiles[tun->numqueues - 1]); 470 ntfile = rtnl_dereference(tun->tfiles[index]); 471 ntfile->queue_index = index; 472 473 --tun->numqueues; 474 if (clean) { 475 RCU_INIT_POINTER(tfile->tun, NULL); 476 sock_put(&tfile->sk); 477 } else 478 tun_disable_queue(tun, tfile); 479 480 synchronize_net(); 481 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 482 /* Drop read queue */ 483 tun_queue_purge(tfile); 484 tun_set_real_num_queues(tun); 485 } else if (tfile->detached && clean) { 486 tun = tun_enable_queue(tfile); 487 sock_put(&tfile->sk); 488 } 489 490 if (clean) { 491 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 492 netif_carrier_off(tun->dev); 493 494 if (!(tun->flags & IFF_PERSIST) && 495 tun->dev->reg_state == NETREG_REGISTERED) 496 unregister_netdevice(tun->dev); 497 } 498 499 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 500 &tfile->socket.flags)); 501 sk_release_kernel(&tfile->sk); 502 } 503 } 504 505 static void tun_detach(struct tun_file *tfile, bool clean) 506 { 507 rtnl_lock(); 508 __tun_detach(tfile, clean); 509 rtnl_unlock(); 510 } 511 512 static void tun_detach_all(struct net_device *dev) 513 { 514 struct tun_struct *tun = netdev_priv(dev); 515 struct tun_file *tfile, *tmp; 516 int i, n = tun->numqueues; 517 518 for (i = 0; i < n; i++) { 519 tfile = rtnl_dereference(tun->tfiles[i]); 520 BUG_ON(!tfile); 521 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 522 RCU_INIT_POINTER(tfile->tun, NULL); 523 --tun->numqueues; 524 } 525 list_for_each_entry(tfile, &tun->disabled, next) { 526 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 527 RCU_INIT_POINTER(tfile->tun, NULL); 528 } 529 BUG_ON(tun->numqueues != 0); 530 531 synchronize_net(); 532 for (i = 0; i < n; i++) { 533 tfile = rtnl_dereference(tun->tfiles[i]); 534 /* Drop read queue */ 535 tun_queue_purge(tfile); 536 sock_put(&tfile->sk); 537 } 538 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 539 tun_enable_queue(tfile); 540 tun_queue_purge(tfile); 541 sock_put(&tfile->sk); 542 } 543 BUG_ON(tun->numdisabled != 0); 544 545 if (tun->flags & IFF_PERSIST) 546 module_put(THIS_MODULE); 547 } 548 549 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) 550 { 551 struct tun_file *tfile = file->private_data; 552 int err; 553 554 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 555 if (err < 0) 556 goto out; 557 558 err = -EINVAL; 559 if (rtnl_dereference(tfile->tun) && !tfile->detached) 560 goto out; 561 562 err = -EBUSY; 563 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1) 564 goto out; 565 566 err = -E2BIG; 567 if (!tfile->detached && 568 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 569 goto out; 570 571 err = 0; 572 573 /* Re-attach the filter to persist device */ 574 if (!skip_filter && (tun->filter_attached == true)) { 575 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 576 if (!err) 577 goto out; 578 } 579 tfile->queue_index = tun->numqueues; 580 rcu_assign_pointer(tfile->tun, tun); 581 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 582 tun->numqueues++; 583 584 if (tfile->detached) 585 tun_enable_queue(tfile); 586 else 587 sock_hold(&tfile->sk); 588 589 tun_set_real_num_queues(tun); 590 591 /* device is allowed to go away first, so no need to hold extra 592 * refcnt. 593 */ 594 595 out: 596 return err; 597 } 598 599 static struct tun_struct *__tun_get(struct tun_file *tfile) 600 { 601 struct tun_struct *tun; 602 603 rcu_read_lock(); 604 tun = rcu_dereference(tfile->tun); 605 if (tun) 606 dev_hold(tun->dev); 607 rcu_read_unlock(); 608 609 return tun; 610 } 611 612 static struct tun_struct *tun_get(struct file *file) 613 { 614 return __tun_get(file->private_data); 615 } 616 617 static void tun_put(struct tun_struct *tun) 618 { 619 dev_put(tun->dev); 620 } 621 622 /* TAP filtering */ 623 static void addr_hash_set(u32 *mask, const u8 *addr) 624 { 625 int n = ether_crc(ETH_ALEN, addr) >> 26; 626 mask[n >> 5] |= (1 << (n & 31)); 627 } 628 629 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 630 { 631 int n = ether_crc(ETH_ALEN, addr) >> 26; 632 return mask[n >> 5] & (1 << (n & 31)); 633 } 634 635 static int update_filter(struct tap_filter *filter, void __user *arg) 636 { 637 struct { u8 u[ETH_ALEN]; } *addr; 638 struct tun_filter uf; 639 int err, alen, n, nexact; 640 641 if (copy_from_user(&uf, arg, sizeof(uf))) 642 return -EFAULT; 643 644 if (!uf.count) { 645 /* Disabled */ 646 filter->count = 0; 647 return 0; 648 } 649 650 alen = ETH_ALEN * uf.count; 651 addr = kmalloc(alen, GFP_KERNEL); 652 if (!addr) 653 return -ENOMEM; 654 655 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 656 err = -EFAULT; 657 goto done; 658 } 659 660 /* The filter is updated without holding any locks. Which is 661 * perfectly safe. We disable it first and in the worst 662 * case we'll accept a few undesired packets. */ 663 filter->count = 0; 664 wmb(); 665 666 /* Use first set of addresses as an exact filter */ 667 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 668 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 669 670 nexact = n; 671 672 /* Remaining multicast addresses are hashed, 673 * unicast will leave the filter disabled. */ 674 memset(filter->mask, 0, sizeof(filter->mask)); 675 for (; n < uf.count; n++) { 676 if (!is_multicast_ether_addr(addr[n].u)) { 677 err = 0; /* no filter */ 678 goto done; 679 } 680 addr_hash_set(filter->mask, addr[n].u); 681 } 682 683 /* For ALLMULTI just set the mask to all ones. 684 * This overrides the mask populated above. */ 685 if ((uf.flags & TUN_FLT_ALLMULTI)) 686 memset(filter->mask, ~0, sizeof(filter->mask)); 687 688 /* Now enable the filter */ 689 wmb(); 690 filter->count = nexact; 691 692 /* Return the number of exact filters */ 693 err = nexact; 694 695 done: 696 kfree(addr); 697 return err; 698 } 699 700 /* Returns: 0 - drop, !=0 - accept */ 701 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 702 { 703 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 704 * at this point. */ 705 struct ethhdr *eh = (struct ethhdr *) skb->data; 706 int i; 707 708 /* Exact match */ 709 for (i = 0; i < filter->count; i++) 710 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 711 return 1; 712 713 /* Inexact match (multicast only) */ 714 if (is_multicast_ether_addr(eh->h_dest)) 715 return addr_hash_test(filter->mask, eh->h_dest); 716 717 return 0; 718 } 719 720 /* 721 * Checks whether the packet is accepted or not. 722 * Returns: 0 - drop, !=0 - accept 723 */ 724 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 725 { 726 if (!filter->count) 727 return 1; 728 729 return run_filter(filter, skb); 730 } 731 732 /* Network device part of the driver */ 733 734 static const struct ethtool_ops tun_ethtool_ops; 735 736 /* Net device detach from fd. */ 737 static void tun_net_uninit(struct net_device *dev) 738 { 739 tun_detach_all(dev); 740 } 741 742 /* Net device open. */ 743 static int tun_net_open(struct net_device *dev) 744 { 745 netif_tx_start_all_queues(dev); 746 return 0; 747 } 748 749 /* Net device close. */ 750 static int tun_net_close(struct net_device *dev) 751 { 752 netif_tx_stop_all_queues(dev); 753 return 0; 754 } 755 756 /* Net device start xmit */ 757 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 758 { 759 struct tun_struct *tun = netdev_priv(dev); 760 int txq = skb->queue_mapping; 761 struct tun_file *tfile; 762 u32 numqueues = 0; 763 764 rcu_read_lock(); 765 tfile = rcu_dereference(tun->tfiles[txq]); 766 numqueues = ACCESS_ONCE(tun->numqueues); 767 768 /* Drop packet if interface is not attached */ 769 if (txq >= numqueues) 770 goto drop; 771 772 if (numqueues == 1) { 773 /* Select queue was not called for the skbuff, so we extract the 774 * RPS hash and save it into the flow_table here. 775 */ 776 __u32 rxhash; 777 778 rxhash = skb_get_hash(skb); 779 if (rxhash) { 780 struct tun_flow_entry *e; 781 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], 782 rxhash); 783 if (e) 784 tun_flow_save_rps_rxhash(e, rxhash); 785 } 786 } 787 788 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 789 790 BUG_ON(!tfile); 791 792 /* Drop if the filter does not like it. 793 * This is a noop if the filter is disabled. 794 * Filter can be enabled only for the TAP devices. */ 795 if (!check_filter(&tun->txflt, skb)) 796 goto drop; 797 798 if (tfile->socket.sk->sk_filter && 799 sk_filter(tfile->socket.sk, skb)) 800 goto drop; 801 802 /* Limit the number of packets queued by dividing txq length with the 803 * number of queues. 804 */ 805 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues 806 >= dev->tx_queue_len) 807 goto drop; 808 809 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 810 goto drop; 811 812 if (skb->sk) { 813 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags); 814 sw_tx_timestamp(skb); 815 } 816 817 /* Orphan the skb - required as we might hang on to it 818 * for indefinite time. 819 */ 820 skb_orphan(skb); 821 822 nf_reset(skb); 823 824 /* Enqueue packet */ 825 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 826 827 /* Notify and wake up reader process */ 828 if (tfile->flags & TUN_FASYNC) 829 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 830 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 831 832 rcu_read_unlock(); 833 return NETDEV_TX_OK; 834 835 drop: 836 dev->stats.tx_dropped++; 837 skb_tx_error(skb); 838 kfree_skb(skb); 839 rcu_read_unlock(); 840 return NETDEV_TX_OK; 841 } 842 843 static void tun_net_mclist(struct net_device *dev) 844 { 845 /* 846 * This callback is supposed to deal with mc filter in 847 * _rx_ path and has nothing to do with the _tx_ path. 848 * In rx path we always accept everything userspace gives us. 849 */ 850 } 851 852 #define MIN_MTU 68 853 #define MAX_MTU 65535 854 855 static int 856 tun_net_change_mtu(struct net_device *dev, int new_mtu) 857 { 858 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 859 return -EINVAL; 860 dev->mtu = new_mtu; 861 return 0; 862 } 863 864 static netdev_features_t tun_net_fix_features(struct net_device *dev, 865 netdev_features_t features) 866 { 867 struct tun_struct *tun = netdev_priv(dev); 868 869 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 870 } 871 #ifdef CONFIG_NET_POLL_CONTROLLER 872 static void tun_poll_controller(struct net_device *dev) 873 { 874 /* 875 * Tun only receives frames when: 876 * 1) the char device endpoint gets data from user space 877 * 2) the tun socket gets a sendmsg call from user space 878 * Since both of those are synchronous operations, we are guaranteed 879 * never to have pending data when we poll for it 880 * so there is nothing to do here but return. 881 * We need this though so netpoll recognizes us as an interface that 882 * supports polling, which enables bridge devices in virt setups to 883 * still use netconsole 884 */ 885 return; 886 } 887 #endif 888 static const struct net_device_ops tun_netdev_ops = { 889 .ndo_uninit = tun_net_uninit, 890 .ndo_open = tun_net_open, 891 .ndo_stop = tun_net_close, 892 .ndo_start_xmit = tun_net_xmit, 893 .ndo_change_mtu = tun_net_change_mtu, 894 .ndo_fix_features = tun_net_fix_features, 895 .ndo_select_queue = tun_select_queue, 896 #ifdef CONFIG_NET_POLL_CONTROLLER 897 .ndo_poll_controller = tun_poll_controller, 898 #endif 899 }; 900 901 static const struct net_device_ops tap_netdev_ops = { 902 .ndo_uninit = tun_net_uninit, 903 .ndo_open = tun_net_open, 904 .ndo_stop = tun_net_close, 905 .ndo_start_xmit = tun_net_xmit, 906 .ndo_change_mtu = tun_net_change_mtu, 907 .ndo_fix_features = tun_net_fix_features, 908 .ndo_set_rx_mode = tun_net_mclist, 909 .ndo_set_mac_address = eth_mac_addr, 910 .ndo_validate_addr = eth_validate_addr, 911 .ndo_select_queue = tun_select_queue, 912 #ifdef CONFIG_NET_POLL_CONTROLLER 913 .ndo_poll_controller = tun_poll_controller, 914 #endif 915 }; 916 917 static void tun_flow_init(struct tun_struct *tun) 918 { 919 int i; 920 921 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 922 INIT_HLIST_HEAD(&tun->flows[i]); 923 924 tun->ageing_time = TUN_FLOW_EXPIRE; 925 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 926 mod_timer(&tun->flow_gc_timer, 927 round_jiffies_up(jiffies + tun->ageing_time)); 928 } 929 930 static void tun_flow_uninit(struct tun_struct *tun) 931 { 932 del_timer_sync(&tun->flow_gc_timer); 933 tun_flow_flush(tun); 934 } 935 936 /* Initialize net device. */ 937 static void tun_net_init(struct net_device *dev) 938 { 939 struct tun_struct *tun = netdev_priv(dev); 940 941 switch (tun->flags & TUN_TYPE_MASK) { 942 case IFF_TUN: 943 dev->netdev_ops = &tun_netdev_ops; 944 945 /* Point-to-Point TUN Device */ 946 dev->hard_header_len = 0; 947 dev->addr_len = 0; 948 dev->mtu = 1500; 949 950 /* Zero header length */ 951 dev->type = ARPHRD_NONE; 952 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 953 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 954 break; 955 956 case IFF_TAP: 957 dev->netdev_ops = &tap_netdev_ops; 958 /* Ethernet TAP Device */ 959 ether_setup(dev); 960 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 961 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 962 963 eth_hw_addr_random(dev); 964 965 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 966 break; 967 } 968 } 969 970 /* Character device part */ 971 972 /* Poll */ 973 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 974 { 975 struct tun_file *tfile = file->private_data; 976 struct tun_struct *tun = __tun_get(tfile); 977 struct sock *sk; 978 unsigned int mask = 0; 979 980 if (!tun) 981 return POLLERR; 982 983 sk = tfile->socket.sk; 984 985 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 986 987 poll_wait(file, sk_sleep(sk), wait); 988 989 if (!skb_queue_empty(&sk->sk_receive_queue)) 990 mask |= POLLIN | POLLRDNORM; 991 992 if (sock_writeable(sk) || 993 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 994 sock_writeable(sk))) 995 mask |= POLLOUT | POLLWRNORM; 996 997 if (tun->dev->reg_state != NETREG_REGISTERED) 998 mask = POLLERR; 999 1000 tun_put(tun); 1001 return mask; 1002 } 1003 1004 /* prepad is the amount to reserve at front. len is length after that. 1005 * linear is a hint as to how much to copy (usually headers). */ 1006 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 1007 size_t prepad, size_t len, 1008 size_t linear, int noblock) 1009 { 1010 struct sock *sk = tfile->socket.sk; 1011 struct sk_buff *skb; 1012 int err; 1013 1014 /* Under a page? Don't bother with paged skb. */ 1015 if (prepad + len < PAGE_SIZE || !linear) 1016 linear = len; 1017 1018 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 1019 &err, 0); 1020 if (!skb) 1021 return ERR_PTR(err); 1022 1023 skb_reserve(skb, prepad); 1024 skb_put(skb, linear); 1025 skb->data_len = len - linear; 1026 skb->len += len - linear; 1027 1028 return skb; 1029 } 1030 1031 /* Get packet from user space buffer */ 1032 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1033 void *msg_control, const struct iovec *iv, 1034 size_t total_len, size_t count, int noblock) 1035 { 1036 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1037 struct sk_buff *skb; 1038 size_t len = total_len, align = NET_SKB_PAD, linear; 1039 struct virtio_net_hdr gso = { 0 }; 1040 int good_linear; 1041 int offset = 0; 1042 int copylen; 1043 bool zerocopy = false; 1044 int err; 1045 u32 rxhash; 1046 1047 if (!(tun->flags & IFF_NO_PI)) { 1048 if (len < sizeof(pi)) 1049 return -EINVAL; 1050 len -= sizeof(pi); 1051 1052 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) 1053 return -EFAULT; 1054 offset += sizeof(pi); 1055 } 1056 1057 if (tun->flags & IFF_VNET_HDR) { 1058 if (len < tun->vnet_hdr_sz) 1059 return -EINVAL; 1060 len -= tun->vnet_hdr_sz; 1061 1062 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) 1063 return -EFAULT; 1064 1065 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1066 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len)) 1067 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2); 1068 1069 if (tun16_to_cpu(tun, gso.hdr_len) > len) 1070 return -EINVAL; 1071 offset += tun->vnet_hdr_sz; 1072 } 1073 1074 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) { 1075 align += NET_IP_ALIGN; 1076 if (unlikely(len < ETH_HLEN || 1077 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN))) 1078 return -EINVAL; 1079 } 1080 1081 good_linear = SKB_MAX_HEAD(align); 1082 1083 if (msg_control) { 1084 /* There are 256 bytes to be copied in skb, so there is 1085 * enough room for skb expand head in case it is used. 1086 * The rest of the buffer is mapped from userspace. 1087 */ 1088 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN; 1089 if (copylen > good_linear) 1090 copylen = good_linear; 1091 linear = copylen; 1092 if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS) 1093 zerocopy = true; 1094 } 1095 1096 if (!zerocopy) { 1097 copylen = len; 1098 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear) 1099 linear = good_linear; 1100 else 1101 linear = tun16_to_cpu(tun, gso.hdr_len); 1102 } 1103 1104 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1105 if (IS_ERR(skb)) { 1106 if (PTR_ERR(skb) != -EAGAIN) 1107 tun->dev->stats.rx_dropped++; 1108 return PTR_ERR(skb); 1109 } 1110 1111 if (zerocopy) 1112 err = zerocopy_sg_from_iovec(skb, iv, offset, count); 1113 else { 1114 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len); 1115 if (!err && msg_control) { 1116 struct ubuf_info *uarg = msg_control; 1117 uarg->callback(uarg, false); 1118 } 1119 } 1120 1121 if (err) { 1122 tun->dev->stats.rx_dropped++; 1123 kfree_skb(skb); 1124 return -EFAULT; 1125 } 1126 1127 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1128 if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start), 1129 tun16_to_cpu(tun, gso.csum_offset))) { 1130 tun->dev->stats.rx_frame_errors++; 1131 kfree_skb(skb); 1132 return -EINVAL; 1133 } 1134 } 1135 1136 switch (tun->flags & TUN_TYPE_MASK) { 1137 case IFF_TUN: 1138 if (tun->flags & IFF_NO_PI) { 1139 switch (skb->data[0] & 0xf0) { 1140 case 0x40: 1141 pi.proto = htons(ETH_P_IP); 1142 break; 1143 case 0x60: 1144 pi.proto = htons(ETH_P_IPV6); 1145 break; 1146 default: 1147 tun->dev->stats.rx_dropped++; 1148 kfree_skb(skb); 1149 return -EINVAL; 1150 } 1151 } 1152 1153 skb_reset_mac_header(skb); 1154 skb->protocol = pi.proto; 1155 skb->dev = tun->dev; 1156 break; 1157 case IFF_TAP: 1158 skb->protocol = eth_type_trans(skb, tun->dev); 1159 break; 1160 } 1161 1162 skb_reset_network_header(skb); 1163 1164 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1165 pr_debug("GSO!\n"); 1166 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1167 case VIRTIO_NET_HDR_GSO_TCPV4: 1168 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1169 break; 1170 case VIRTIO_NET_HDR_GSO_TCPV6: 1171 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1172 break; 1173 case VIRTIO_NET_HDR_GSO_UDP: 1174 { 1175 static bool warned; 1176 1177 if (!warned) { 1178 warned = true; 1179 netdev_warn(tun->dev, 1180 "%s: using disabled UFO feature; please fix this program\n", 1181 current->comm); 1182 } 1183 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1184 if (skb->protocol == htons(ETH_P_IPV6)) 1185 ipv6_proxy_select_ident(skb); 1186 break; 1187 } 1188 default: 1189 tun->dev->stats.rx_frame_errors++; 1190 kfree_skb(skb); 1191 return -EINVAL; 1192 } 1193 1194 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1195 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1196 1197 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size); 1198 if (skb_shinfo(skb)->gso_size == 0) { 1199 tun->dev->stats.rx_frame_errors++; 1200 kfree_skb(skb); 1201 return -EINVAL; 1202 } 1203 1204 /* Header must be checked, and gso_segs computed. */ 1205 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1206 skb_shinfo(skb)->gso_segs = 0; 1207 } 1208 1209 /* copy skb_ubuf_info for callback when skb has no error */ 1210 if (zerocopy) { 1211 skb_shinfo(skb)->destructor_arg = msg_control; 1212 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1213 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1214 } 1215 1216 skb_probe_transport_header(skb, 0); 1217 1218 rxhash = skb_get_hash(skb); 1219 netif_rx_ni(skb); 1220 1221 tun->dev->stats.rx_packets++; 1222 tun->dev->stats.rx_bytes += len; 1223 1224 tun_flow_update(tun, rxhash, tfile); 1225 return total_len; 1226 } 1227 1228 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 1229 unsigned long count, loff_t pos) 1230 { 1231 struct file *file = iocb->ki_filp; 1232 struct tun_struct *tun = tun_get(file); 1233 struct tun_file *tfile = file->private_data; 1234 ssize_t result; 1235 1236 if (!tun) 1237 return -EBADFD; 1238 1239 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count); 1240 1241 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count), 1242 count, file->f_flags & O_NONBLOCK); 1243 1244 tun_put(tun); 1245 return result; 1246 } 1247 1248 /* Put packet to the user space buffer */ 1249 static ssize_t tun_put_user(struct tun_struct *tun, 1250 struct tun_file *tfile, 1251 struct sk_buff *skb, 1252 const struct iovec *iv, int len) 1253 { 1254 struct tun_pi pi = { 0, skb->protocol }; 1255 ssize_t total = 0; 1256 int vlan_offset = 0, copied; 1257 int vlan_hlen = 0; 1258 int vnet_hdr_sz = 0; 1259 1260 if (vlan_tx_tag_present(skb)) 1261 vlan_hlen = VLAN_HLEN; 1262 1263 if (tun->flags & IFF_VNET_HDR) 1264 vnet_hdr_sz = tun->vnet_hdr_sz; 1265 1266 if (!(tun->flags & IFF_NO_PI)) { 1267 if ((len -= sizeof(pi)) < 0) 1268 return -EINVAL; 1269 1270 if (len < skb->len + vlan_hlen + vnet_hdr_sz) { 1271 /* Packet will be striped */ 1272 pi.flags |= TUN_PKT_STRIP; 1273 } 1274 1275 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi))) 1276 return -EFAULT; 1277 total += sizeof(pi); 1278 } 1279 1280 if (vnet_hdr_sz) { 1281 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1282 if ((len -= vnet_hdr_sz) < 0) 1283 return -EINVAL; 1284 1285 if (skb_is_gso(skb)) { 1286 struct skb_shared_info *sinfo = skb_shinfo(skb); 1287 1288 /* This is a hint as to how much should be linear. */ 1289 gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb)); 1290 gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size); 1291 if (sinfo->gso_type & SKB_GSO_TCPV4) 1292 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1293 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1294 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1295 else { 1296 pr_err("unexpected GSO type: " 1297 "0x%x, gso_size %d, hdr_len %d\n", 1298 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size), 1299 tun16_to_cpu(tun, gso.hdr_len)); 1300 print_hex_dump(KERN_ERR, "tun: ", 1301 DUMP_PREFIX_NONE, 1302 16, 1, skb->head, 1303 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true); 1304 WARN_ON_ONCE(1); 1305 return -EINVAL; 1306 } 1307 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1308 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1309 } else 1310 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1311 1312 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1313 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1314 gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) + 1315 vlan_hlen); 1316 gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset); 1317 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1318 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1319 } /* else everything is zero */ 1320 1321 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, 1322 sizeof(gso)))) 1323 return -EFAULT; 1324 total += vnet_hdr_sz; 1325 } 1326 1327 copied = total; 1328 len = min_t(int, skb->len + vlan_hlen, len); 1329 total += skb->len + vlan_hlen; 1330 if (vlan_hlen) { 1331 int copy, ret; 1332 struct { 1333 __be16 h_vlan_proto; 1334 __be16 h_vlan_TCI; 1335 } veth; 1336 1337 veth.h_vlan_proto = skb->vlan_proto; 1338 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 1339 1340 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1341 1342 copy = min_t(int, vlan_offset, len); 1343 ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); 1344 len -= copy; 1345 copied += copy; 1346 if (ret || !len) 1347 goto done; 1348 1349 copy = min_t(int, sizeof(veth), len); 1350 ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy); 1351 len -= copy; 1352 copied += copy; 1353 if (ret || !len) 1354 goto done; 1355 } 1356 1357 skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len); 1358 1359 done: 1360 tun->dev->stats.tx_packets++; 1361 tun->dev->stats.tx_bytes += len; 1362 1363 return total; 1364 } 1365 1366 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1367 const struct iovec *iv, ssize_t len, int noblock) 1368 { 1369 struct sk_buff *skb; 1370 ssize_t ret = 0; 1371 int peeked, err, off = 0; 1372 1373 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1374 1375 if (!len) 1376 return ret; 1377 1378 if (tun->dev->reg_state != NETREG_REGISTERED) 1379 return -EIO; 1380 1381 /* Read frames from queue */ 1382 skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0, 1383 &peeked, &off, &err); 1384 if (skb) { 1385 ret = tun_put_user(tun, tfile, skb, iv, len); 1386 kfree_skb(skb); 1387 } else 1388 ret = err; 1389 1390 return ret; 1391 } 1392 1393 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 1394 unsigned long count, loff_t pos) 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, ret; 1400 1401 if (!tun) 1402 return -EBADFD; 1403 len = iov_length(iv, count); 1404 if (len < 0) { 1405 ret = -EINVAL; 1406 goto out; 1407 } 1408 1409 ret = tun_do_read(tun, tfile, iv, len, 1410 file->f_flags & O_NONBLOCK); 1411 ret = min_t(ssize_t, ret, len); 1412 if (ret > 0) 1413 iocb->ki_pos = ret; 1414 out: 1415 tun_put(tun); 1416 return ret; 1417 } 1418 1419 static void tun_free_netdev(struct net_device *dev) 1420 { 1421 struct tun_struct *tun = netdev_priv(dev); 1422 1423 BUG_ON(!(list_empty(&tun->disabled))); 1424 tun_flow_uninit(tun); 1425 security_tun_dev_free_security(tun->security); 1426 free_netdev(dev); 1427 } 1428 1429 static void tun_setup(struct net_device *dev) 1430 { 1431 struct tun_struct *tun = netdev_priv(dev); 1432 1433 tun->owner = INVALID_UID; 1434 tun->group = INVALID_GID; 1435 1436 dev->ethtool_ops = &tun_ethtool_ops; 1437 dev->destructor = tun_free_netdev; 1438 } 1439 1440 /* Trivial set of netlink ops to allow deleting tun or tap 1441 * device with netlink. 1442 */ 1443 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1444 { 1445 return -EINVAL; 1446 } 1447 1448 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1449 .kind = DRV_NAME, 1450 .priv_size = sizeof(struct tun_struct), 1451 .setup = tun_setup, 1452 .validate = tun_validate, 1453 }; 1454 1455 static void tun_sock_write_space(struct sock *sk) 1456 { 1457 struct tun_file *tfile; 1458 wait_queue_head_t *wqueue; 1459 1460 if (!sock_writeable(sk)) 1461 return; 1462 1463 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1464 return; 1465 1466 wqueue = sk_sleep(sk); 1467 if (wqueue && waitqueue_active(wqueue)) 1468 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1469 POLLWRNORM | POLLWRBAND); 1470 1471 tfile = container_of(sk, struct tun_file, sk); 1472 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1473 } 1474 1475 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1476 struct msghdr *m, size_t total_len) 1477 { 1478 int ret; 1479 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1480 struct tun_struct *tun = __tun_get(tfile); 1481 1482 if (!tun) 1483 return -EBADFD; 1484 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len, 1485 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); 1486 tun_put(tun); 1487 return ret; 1488 } 1489 1490 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1491 struct msghdr *m, size_t total_len, 1492 int flags) 1493 { 1494 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1495 struct tun_struct *tun = __tun_get(tfile); 1496 int ret; 1497 1498 if (!tun) 1499 return -EBADFD; 1500 1501 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1502 ret = -EINVAL; 1503 goto out; 1504 } 1505 if (flags & MSG_ERRQUEUE) { 1506 ret = sock_recv_errqueue(sock->sk, m, total_len, 1507 SOL_PACKET, TUN_TX_TIMESTAMP); 1508 goto out; 1509 } 1510 ret = tun_do_read(tun, tfile, m->msg_iov, total_len, 1511 flags & MSG_DONTWAIT); 1512 if (ret > total_len) { 1513 m->msg_flags |= MSG_TRUNC; 1514 ret = flags & MSG_TRUNC ? ret : total_len; 1515 } 1516 out: 1517 tun_put(tun); 1518 return ret; 1519 } 1520 1521 static int tun_release(struct socket *sock) 1522 { 1523 if (sock->sk) 1524 sock_put(sock->sk); 1525 return 0; 1526 } 1527 1528 /* Ops structure to mimic raw sockets with tun */ 1529 static const struct proto_ops tun_socket_ops = { 1530 .sendmsg = tun_sendmsg, 1531 .recvmsg = tun_recvmsg, 1532 .release = tun_release, 1533 }; 1534 1535 static struct proto tun_proto = { 1536 .name = "tun", 1537 .owner = THIS_MODULE, 1538 .obj_size = sizeof(struct tun_file), 1539 }; 1540 1541 static int tun_flags(struct tun_struct *tun) 1542 { 1543 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP); 1544 } 1545 1546 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1547 char *buf) 1548 { 1549 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1550 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1551 } 1552 1553 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1554 char *buf) 1555 { 1556 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1557 return uid_valid(tun->owner)? 1558 sprintf(buf, "%u\n", 1559 from_kuid_munged(current_user_ns(), tun->owner)): 1560 sprintf(buf, "-1\n"); 1561 } 1562 1563 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1564 char *buf) 1565 { 1566 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1567 return gid_valid(tun->group) ? 1568 sprintf(buf, "%u\n", 1569 from_kgid_munged(current_user_ns(), tun->group)): 1570 sprintf(buf, "-1\n"); 1571 } 1572 1573 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1574 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1575 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1576 1577 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1578 { 1579 struct tun_struct *tun; 1580 struct tun_file *tfile = file->private_data; 1581 struct net_device *dev; 1582 int err; 1583 1584 if (tfile->detached) 1585 return -EINVAL; 1586 1587 dev = __dev_get_by_name(net, ifr->ifr_name); 1588 if (dev) { 1589 if (ifr->ifr_flags & IFF_TUN_EXCL) 1590 return -EBUSY; 1591 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1592 tun = netdev_priv(dev); 1593 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1594 tun = netdev_priv(dev); 1595 else 1596 return -EINVAL; 1597 1598 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1599 !!(tun->flags & IFF_MULTI_QUEUE)) 1600 return -EINVAL; 1601 1602 if (tun_not_capable(tun)) 1603 return -EPERM; 1604 err = security_tun_dev_open(tun->security); 1605 if (err < 0) 1606 return err; 1607 1608 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1609 if (err < 0) 1610 return err; 1611 1612 if (tun->flags & IFF_MULTI_QUEUE && 1613 (tun->numqueues + tun->numdisabled > 1)) { 1614 /* One or more queue has already been attached, no need 1615 * to initialize the device again. 1616 */ 1617 return 0; 1618 } 1619 } 1620 else { 1621 char *name; 1622 unsigned long flags = 0; 1623 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1624 MAX_TAP_QUEUES : 1; 1625 1626 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1627 return -EPERM; 1628 err = security_tun_dev_create(); 1629 if (err < 0) 1630 return err; 1631 1632 /* Set dev type */ 1633 if (ifr->ifr_flags & IFF_TUN) { 1634 /* TUN device */ 1635 flags |= IFF_TUN; 1636 name = "tun%d"; 1637 } else if (ifr->ifr_flags & IFF_TAP) { 1638 /* TAP device */ 1639 flags |= IFF_TAP; 1640 name = "tap%d"; 1641 } else 1642 return -EINVAL; 1643 1644 if (*ifr->ifr_name) 1645 name = ifr->ifr_name; 1646 1647 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1648 NET_NAME_UNKNOWN, tun_setup, queues, 1649 queues); 1650 1651 if (!dev) 1652 return -ENOMEM; 1653 1654 dev_net_set(dev, net); 1655 dev->rtnl_link_ops = &tun_link_ops; 1656 dev->ifindex = tfile->ifindex; 1657 1658 tun = netdev_priv(dev); 1659 tun->dev = dev; 1660 tun->flags = flags; 1661 tun->txflt.count = 0; 1662 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1663 1664 tun->filter_attached = false; 1665 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1666 1667 spin_lock_init(&tun->lock); 1668 1669 err = security_tun_dev_alloc_security(&tun->security); 1670 if (err < 0) 1671 goto err_free_dev; 1672 1673 tun_net_init(dev); 1674 tun_flow_init(tun); 1675 1676 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1677 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1678 NETIF_F_HW_VLAN_STAG_TX; 1679 dev->features = dev->hw_features; 1680 dev->vlan_features = dev->features & 1681 ~(NETIF_F_HW_VLAN_CTAG_TX | 1682 NETIF_F_HW_VLAN_STAG_TX); 1683 1684 INIT_LIST_HEAD(&tun->disabled); 1685 err = tun_attach(tun, file, false); 1686 if (err < 0) 1687 goto err_free_flow; 1688 1689 err = register_netdevice(tun->dev); 1690 if (err < 0) 1691 goto err_detach; 1692 1693 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1694 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1695 device_create_file(&tun->dev->dev, &dev_attr_group)) 1696 pr_err("Failed to create tun sysfs files\n"); 1697 } 1698 1699 netif_carrier_on(tun->dev); 1700 1701 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1702 1703 tun->flags = (tun->flags & ~TUN_FEATURES) | 1704 (ifr->ifr_flags & TUN_FEATURES); 1705 1706 /* Make sure persistent devices do not get stuck in 1707 * xoff state. 1708 */ 1709 if (netif_running(tun->dev)) 1710 netif_tx_wake_all_queues(tun->dev); 1711 1712 strcpy(ifr->ifr_name, tun->dev->name); 1713 return 0; 1714 1715 err_detach: 1716 tun_detach_all(dev); 1717 err_free_flow: 1718 tun_flow_uninit(tun); 1719 security_tun_dev_free_security(tun->security); 1720 err_free_dev: 1721 free_netdev(dev); 1722 return err; 1723 } 1724 1725 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1726 struct ifreq *ifr) 1727 { 1728 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1729 1730 strcpy(ifr->ifr_name, tun->dev->name); 1731 1732 ifr->ifr_flags = tun_flags(tun); 1733 1734 } 1735 1736 /* This is like a cut-down ethtool ops, except done via tun fd so no 1737 * privs required. */ 1738 static int set_offload(struct tun_struct *tun, unsigned long arg) 1739 { 1740 netdev_features_t features = 0; 1741 1742 if (arg & TUN_F_CSUM) { 1743 features |= NETIF_F_HW_CSUM; 1744 arg &= ~TUN_F_CSUM; 1745 1746 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1747 if (arg & TUN_F_TSO_ECN) { 1748 features |= NETIF_F_TSO_ECN; 1749 arg &= ~TUN_F_TSO_ECN; 1750 } 1751 if (arg & TUN_F_TSO4) 1752 features |= NETIF_F_TSO; 1753 if (arg & TUN_F_TSO6) 1754 features |= NETIF_F_TSO6; 1755 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1756 } 1757 } 1758 1759 /* This gives the user a way to test for new features in future by 1760 * trying to set them. */ 1761 if (arg) 1762 return -EINVAL; 1763 1764 tun->set_features = features; 1765 netdev_update_features(tun->dev); 1766 1767 return 0; 1768 } 1769 1770 static void tun_detach_filter(struct tun_struct *tun, int n) 1771 { 1772 int i; 1773 struct tun_file *tfile; 1774 1775 for (i = 0; i < n; i++) { 1776 tfile = rtnl_dereference(tun->tfiles[i]); 1777 sk_detach_filter(tfile->socket.sk); 1778 } 1779 1780 tun->filter_attached = false; 1781 } 1782 1783 static int tun_attach_filter(struct tun_struct *tun) 1784 { 1785 int i, ret = 0; 1786 struct tun_file *tfile; 1787 1788 for (i = 0; i < tun->numqueues; i++) { 1789 tfile = rtnl_dereference(tun->tfiles[i]); 1790 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1791 if (ret) { 1792 tun_detach_filter(tun, i); 1793 return ret; 1794 } 1795 } 1796 1797 tun->filter_attached = true; 1798 return ret; 1799 } 1800 1801 static void tun_set_sndbuf(struct tun_struct *tun) 1802 { 1803 struct tun_file *tfile; 1804 int i; 1805 1806 for (i = 0; i < tun->numqueues; i++) { 1807 tfile = rtnl_dereference(tun->tfiles[i]); 1808 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1809 } 1810 } 1811 1812 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1813 { 1814 struct tun_file *tfile = file->private_data; 1815 struct tun_struct *tun; 1816 int ret = 0; 1817 1818 rtnl_lock(); 1819 1820 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1821 tun = tfile->detached; 1822 if (!tun) { 1823 ret = -EINVAL; 1824 goto unlock; 1825 } 1826 ret = security_tun_dev_attach_queue(tun->security); 1827 if (ret < 0) 1828 goto unlock; 1829 ret = tun_attach(tun, file, false); 1830 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1831 tun = rtnl_dereference(tfile->tun); 1832 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached) 1833 ret = -EINVAL; 1834 else 1835 __tun_detach(tfile, false); 1836 } else 1837 ret = -EINVAL; 1838 1839 unlock: 1840 rtnl_unlock(); 1841 return ret; 1842 } 1843 1844 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1845 unsigned long arg, int ifreq_len) 1846 { 1847 struct tun_file *tfile = file->private_data; 1848 struct tun_struct *tun; 1849 void __user* argp = (void __user*)arg; 1850 struct ifreq ifr; 1851 kuid_t owner; 1852 kgid_t group; 1853 int sndbuf; 1854 int vnet_hdr_sz; 1855 unsigned int ifindex; 1856 int ret; 1857 1858 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1859 if (copy_from_user(&ifr, argp, ifreq_len)) 1860 return -EFAULT; 1861 } else { 1862 memset(&ifr, 0, sizeof(ifr)); 1863 } 1864 if (cmd == TUNGETFEATURES) { 1865 /* Currently this just means: "what IFF flags are valid?". 1866 * This is needed because we never checked for invalid flags on 1867 * TUNSETIFF. 1868 */ 1869 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES, 1870 (unsigned int __user*)argp); 1871 } else if (cmd == TUNSETQUEUE) 1872 return tun_set_queue(file, &ifr); 1873 1874 ret = 0; 1875 rtnl_lock(); 1876 1877 tun = __tun_get(tfile); 1878 if (cmd == TUNSETIFF && !tun) { 1879 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1880 1881 ret = tun_set_iff(tfile->net, file, &ifr); 1882 1883 if (ret) 1884 goto unlock; 1885 1886 if (copy_to_user(argp, &ifr, ifreq_len)) 1887 ret = -EFAULT; 1888 goto unlock; 1889 } 1890 if (cmd == TUNSETIFINDEX) { 1891 ret = -EPERM; 1892 if (tun) 1893 goto unlock; 1894 1895 ret = -EFAULT; 1896 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1897 goto unlock; 1898 1899 ret = 0; 1900 tfile->ifindex = ifindex; 1901 goto unlock; 1902 } 1903 1904 ret = -EBADFD; 1905 if (!tun) 1906 goto unlock; 1907 1908 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1909 1910 ret = 0; 1911 switch (cmd) { 1912 case TUNGETIFF: 1913 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1914 1915 if (tfile->detached) 1916 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1917 if (!tfile->socket.sk->sk_filter) 1918 ifr.ifr_flags |= IFF_NOFILTER; 1919 1920 if (copy_to_user(argp, &ifr, ifreq_len)) 1921 ret = -EFAULT; 1922 break; 1923 1924 case TUNSETNOCSUM: 1925 /* Disable/Enable checksum */ 1926 1927 /* [unimplemented] */ 1928 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1929 arg ? "disabled" : "enabled"); 1930 break; 1931 1932 case TUNSETPERSIST: 1933 /* Disable/Enable persist mode. Keep an extra reference to the 1934 * module to prevent the module being unprobed. 1935 */ 1936 if (arg && !(tun->flags & IFF_PERSIST)) { 1937 tun->flags |= IFF_PERSIST; 1938 __module_get(THIS_MODULE); 1939 } 1940 if (!arg && (tun->flags & IFF_PERSIST)) { 1941 tun->flags &= ~IFF_PERSIST; 1942 module_put(THIS_MODULE); 1943 } 1944 1945 tun_debug(KERN_INFO, tun, "persist %s\n", 1946 arg ? "enabled" : "disabled"); 1947 break; 1948 1949 case TUNSETOWNER: 1950 /* Set owner of the device */ 1951 owner = make_kuid(current_user_ns(), arg); 1952 if (!uid_valid(owner)) { 1953 ret = -EINVAL; 1954 break; 1955 } 1956 tun->owner = owner; 1957 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1958 from_kuid(&init_user_ns, tun->owner)); 1959 break; 1960 1961 case TUNSETGROUP: 1962 /* Set group of the device */ 1963 group = make_kgid(current_user_ns(), arg); 1964 if (!gid_valid(group)) { 1965 ret = -EINVAL; 1966 break; 1967 } 1968 tun->group = group; 1969 tun_debug(KERN_INFO, tun, "group set to %u\n", 1970 from_kgid(&init_user_ns, tun->group)); 1971 break; 1972 1973 case TUNSETLINK: 1974 /* Only allow setting the type when the interface is down */ 1975 if (tun->dev->flags & IFF_UP) { 1976 tun_debug(KERN_INFO, tun, 1977 "Linktype set failed because interface is up\n"); 1978 ret = -EBUSY; 1979 } else { 1980 tun->dev->type = (int) arg; 1981 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1982 tun->dev->type); 1983 ret = 0; 1984 } 1985 break; 1986 1987 #ifdef TUN_DEBUG 1988 case TUNSETDEBUG: 1989 tun->debug = arg; 1990 break; 1991 #endif 1992 case TUNSETOFFLOAD: 1993 ret = set_offload(tun, arg); 1994 break; 1995 1996 case TUNSETTXFILTER: 1997 /* Can be set only for TAPs */ 1998 ret = -EINVAL; 1999 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2000 break; 2001 ret = update_filter(&tun->txflt, (void __user *)arg); 2002 break; 2003 2004 case SIOCGIFHWADDR: 2005 /* Get hw address */ 2006 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 2007 ifr.ifr_hwaddr.sa_family = tun->dev->type; 2008 if (copy_to_user(argp, &ifr, ifreq_len)) 2009 ret = -EFAULT; 2010 break; 2011 2012 case SIOCSIFHWADDR: 2013 /* Set hw address */ 2014 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 2015 ifr.ifr_hwaddr.sa_data); 2016 2017 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2018 break; 2019 2020 case TUNGETSNDBUF: 2021 sndbuf = tfile->socket.sk->sk_sndbuf; 2022 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2023 ret = -EFAULT; 2024 break; 2025 2026 case TUNSETSNDBUF: 2027 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2028 ret = -EFAULT; 2029 break; 2030 } 2031 2032 tun->sndbuf = sndbuf; 2033 tun_set_sndbuf(tun); 2034 break; 2035 2036 case TUNGETVNETHDRSZ: 2037 vnet_hdr_sz = tun->vnet_hdr_sz; 2038 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2039 ret = -EFAULT; 2040 break; 2041 2042 case TUNSETVNETHDRSZ: 2043 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2044 ret = -EFAULT; 2045 break; 2046 } 2047 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2048 ret = -EINVAL; 2049 break; 2050 } 2051 2052 tun->vnet_hdr_sz = vnet_hdr_sz; 2053 break; 2054 2055 case TUNATTACHFILTER: 2056 /* Can be set only for TAPs */ 2057 ret = -EINVAL; 2058 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2059 break; 2060 ret = -EFAULT; 2061 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2062 break; 2063 2064 ret = tun_attach_filter(tun); 2065 break; 2066 2067 case TUNDETACHFILTER: 2068 /* Can be set only for TAPs */ 2069 ret = -EINVAL; 2070 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2071 break; 2072 ret = 0; 2073 tun_detach_filter(tun, tun->numqueues); 2074 break; 2075 2076 case TUNGETFILTER: 2077 ret = -EINVAL; 2078 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2079 break; 2080 ret = -EFAULT; 2081 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2082 break; 2083 ret = 0; 2084 break; 2085 2086 default: 2087 ret = -EINVAL; 2088 break; 2089 } 2090 2091 unlock: 2092 rtnl_unlock(); 2093 if (tun) 2094 tun_put(tun); 2095 return ret; 2096 } 2097 2098 static long tun_chr_ioctl(struct file *file, 2099 unsigned int cmd, unsigned long arg) 2100 { 2101 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2102 } 2103 2104 #ifdef CONFIG_COMPAT 2105 static long tun_chr_compat_ioctl(struct file *file, 2106 unsigned int cmd, unsigned long arg) 2107 { 2108 switch (cmd) { 2109 case TUNSETIFF: 2110 case TUNGETIFF: 2111 case TUNSETTXFILTER: 2112 case TUNGETSNDBUF: 2113 case TUNSETSNDBUF: 2114 case SIOCGIFHWADDR: 2115 case SIOCSIFHWADDR: 2116 arg = (unsigned long)compat_ptr(arg); 2117 break; 2118 default: 2119 arg = (compat_ulong_t)arg; 2120 break; 2121 } 2122 2123 /* 2124 * compat_ifreq is shorter than ifreq, so we must not access beyond 2125 * the end of that structure. All fields that are used in this 2126 * driver are compatible though, we don't need to convert the 2127 * contents. 2128 */ 2129 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2130 } 2131 #endif /* CONFIG_COMPAT */ 2132 2133 static int tun_chr_fasync(int fd, struct file *file, int on) 2134 { 2135 struct tun_file *tfile = file->private_data; 2136 int ret; 2137 2138 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2139 goto out; 2140 2141 if (on) { 2142 __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2143 tfile->flags |= TUN_FASYNC; 2144 } else 2145 tfile->flags &= ~TUN_FASYNC; 2146 ret = 0; 2147 out: 2148 return ret; 2149 } 2150 2151 static int tun_chr_open(struct inode *inode, struct file * file) 2152 { 2153 struct tun_file *tfile; 2154 2155 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2156 2157 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2158 &tun_proto); 2159 if (!tfile) 2160 return -ENOMEM; 2161 RCU_INIT_POINTER(tfile->tun, NULL); 2162 tfile->net = get_net(current->nsproxy->net_ns); 2163 tfile->flags = 0; 2164 tfile->ifindex = 0; 2165 2166 init_waitqueue_head(&tfile->wq.wait); 2167 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq); 2168 2169 tfile->socket.file = file; 2170 tfile->socket.ops = &tun_socket_ops; 2171 2172 sock_init_data(&tfile->socket, &tfile->sk); 2173 sk_change_net(&tfile->sk, tfile->net); 2174 2175 tfile->sk.sk_write_space = tun_sock_write_space; 2176 tfile->sk.sk_sndbuf = INT_MAX; 2177 2178 file->private_data = tfile; 2179 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2180 INIT_LIST_HEAD(&tfile->next); 2181 2182 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2183 2184 return 0; 2185 } 2186 2187 static int tun_chr_close(struct inode *inode, struct file *file) 2188 { 2189 struct tun_file *tfile = file->private_data; 2190 struct net *net = tfile->net; 2191 2192 tun_detach(tfile, true); 2193 put_net(net); 2194 2195 return 0; 2196 } 2197 2198 #ifdef CONFIG_PROC_FS 2199 static int tun_chr_show_fdinfo(struct seq_file *m, struct file *f) 2200 { 2201 struct tun_struct *tun; 2202 struct ifreq ifr; 2203 2204 memset(&ifr, 0, sizeof(ifr)); 2205 2206 rtnl_lock(); 2207 tun = tun_get(f); 2208 if (tun) 2209 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 2210 rtnl_unlock(); 2211 2212 if (tun) 2213 tun_put(tun); 2214 2215 return seq_printf(m, "iff:\t%s\n", ifr.ifr_name); 2216 } 2217 #endif 2218 2219 static const struct file_operations tun_fops = { 2220 .owner = THIS_MODULE, 2221 .llseek = no_llseek, 2222 .read = do_sync_read, 2223 .aio_read = tun_chr_aio_read, 2224 .write = do_sync_write, 2225 .aio_write = tun_chr_aio_write, 2226 .poll = tun_chr_poll, 2227 .unlocked_ioctl = tun_chr_ioctl, 2228 #ifdef CONFIG_COMPAT 2229 .compat_ioctl = tun_chr_compat_ioctl, 2230 #endif 2231 .open = tun_chr_open, 2232 .release = tun_chr_close, 2233 .fasync = tun_chr_fasync, 2234 #ifdef CONFIG_PROC_FS 2235 .show_fdinfo = tun_chr_show_fdinfo, 2236 #endif 2237 }; 2238 2239 static struct miscdevice tun_miscdev = { 2240 .minor = TUN_MINOR, 2241 .name = "tun", 2242 .nodename = "net/tun", 2243 .fops = &tun_fops, 2244 }; 2245 2246 /* ethtool interface */ 2247 2248 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2249 { 2250 cmd->supported = 0; 2251 cmd->advertising = 0; 2252 ethtool_cmd_speed_set(cmd, SPEED_10); 2253 cmd->duplex = DUPLEX_FULL; 2254 cmd->port = PORT_TP; 2255 cmd->phy_address = 0; 2256 cmd->transceiver = XCVR_INTERNAL; 2257 cmd->autoneg = AUTONEG_DISABLE; 2258 cmd->maxtxpkt = 0; 2259 cmd->maxrxpkt = 0; 2260 return 0; 2261 } 2262 2263 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2264 { 2265 struct tun_struct *tun = netdev_priv(dev); 2266 2267 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2268 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2269 2270 switch (tun->flags & TUN_TYPE_MASK) { 2271 case IFF_TUN: 2272 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2273 break; 2274 case IFF_TAP: 2275 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2276 break; 2277 } 2278 } 2279 2280 static u32 tun_get_msglevel(struct net_device *dev) 2281 { 2282 #ifdef TUN_DEBUG 2283 struct tun_struct *tun = netdev_priv(dev); 2284 return tun->debug; 2285 #else 2286 return -EOPNOTSUPP; 2287 #endif 2288 } 2289 2290 static void tun_set_msglevel(struct net_device *dev, u32 value) 2291 { 2292 #ifdef TUN_DEBUG 2293 struct tun_struct *tun = netdev_priv(dev); 2294 tun->debug = value; 2295 #endif 2296 } 2297 2298 static const struct ethtool_ops tun_ethtool_ops = { 2299 .get_settings = tun_get_settings, 2300 .get_drvinfo = tun_get_drvinfo, 2301 .get_msglevel = tun_get_msglevel, 2302 .set_msglevel = tun_set_msglevel, 2303 .get_link = ethtool_op_get_link, 2304 .get_ts_info = ethtool_op_get_ts_info, 2305 }; 2306 2307 2308 static int __init tun_init(void) 2309 { 2310 int ret = 0; 2311 2312 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2313 pr_info("%s\n", DRV_COPYRIGHT); 2314 2315 ret = rtnl_link_register(&tun_link_ops); 2316 if (ret) { 2317 pr_err("Can't register link_ops\n"); 2318 goto err_linkops; 2319 } 2320 2321 ret = misc_register(&tun_miscdev); 2322 if (ret) { 2323 pr_err("Can't register misc device %d\n", TUN_MINOR); 2324 goto err_misc; 2325 } 2326 return 0; 2327 err_misc: 2328 rtnl_link_unregister(&tun_link_ops); 2329 err_linkops: 2330 return ret; 2331 } 2332 2333 static void tun_cleanup(void) 2334 { 2335 misc_deregister(&tun_miscdev); 2336 rtnl_link_unregister(&tun_link_ops); 2337 } 2338 2339 /* Get an underlying socket object from tun file. Returns error unless file is 2340 * attached to a device. The returned object works like a packet socket, it 2341 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2342 * holding a reference to the file for as long as the socket is in use. */ 2343 struct socket *tun_get_socket(struct file *file) 2344 { 2345 struct tun_file *tfile; 2346 if (file->f_op != &tun_fops) 2347 return ERR_PTR(-EINVAL); 2348 tfile = file->private_data; 2349 if (!tfile) 2350 return ERR_PTR(-EBADFD); 2351 return &tfile->socket; 2352 } 2353 EXPORT_SYMBOL_GPL(tun_get_socket); 2354 2355 module_init(tun_init); 2356 module_exit(tun_cleanup); 2357 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2358 MODULE_AUTHOR(DRV_COPYRIGHT); 2359 MODULE_LICENSE("GPL"); 2360 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2361 MODULE_ALIAS("devname:net/tun"); 2362