1 /* 2 * TUN - Universal TUN/TAP device driver. 3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $ 16 */ 17 18 /* 19 * Changes: 20 * 21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14 22 * Add TUNSETLINK ioctl to set the link encapsulation 23 * 24 * Mark Smith <markzzzsmith@yahoo.com.au> 25 * Use eth_random_addr() for tap MAC address. 26 * 27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20 28 * Fixes in packet dropping, queue length setting and queue wakeup. 29 * Increased default tx queue length. 30 * Added ethtool API. 31 * Minor cleanups 32 * 33 * Daniel Podlejski <underley@underley.eu.org> 34 * Modifications for 2.3.99-pre5 kernel. 35 */ 36 37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 38 39 #define DRV_NAME "tun" 40 #define DRV_VERSION "1.6" 41 #define DRV_DESCRIPTION "Universal TUN/TAP device driver" 42 #define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>" 43 44 #include <linux/module.h> 45 #include <linux/errno.h> 46 #include <linux/kernel.h> 47 #include <linux/major.h> 48 #include <linux/slab.h> 49 #include <linux/poll.h> 50 #include <linux/fcntl.h> 51 #include <linux/init.h> 52 #include <linux/skbuff.h> 53 #include <linux/netdevice.h> 54 #include <linux/etherdevice.h> 55 #include <linux/miscdevice.h> 56 #include <linux/ethtool.h> 57 #include <linux/rtnetlink.h> 58 #include <linux/compat.h> 59 #include <linux/if.h> 60 #include <linux/if_arp.h> 61 #include <linux/if_ether.h> 62 #include <linux/if_tun.h> 63 #include <linux/if_vlan.h> 64 #include <linux/crc32.h> 65 #include <linux/nsproxy.h> 66 #include <linux/virtio_net.h> 67 #include <linux/rcupdate.h> 68 #include <net/net_namespace.h> 69 #include <net/netns/generic.h> 70 #include <net/rtnetlink.h> 71 #include <net/sock.h> 72 #include <linux/seq_file.h> 73 #include <linux/uio.h> 74 75 #include <asm/uaccess.h> 76 77 /* Uncomment to enable debugging */ 78 /* #define TUN_DEBUG 1 */ 79 80 #ifdef TUN_DEBUG 81 static int debug; 82 83 #define tun_debug(level, tun, fmt, args...) \ 84 do { \ 85 if (tun->debug) \ 86 netdev_printk(level, tun->dev, fmt, ##args); \ 87 } while (0) 88 #define DBG1(level, fmt, args...) \ 89 do { \ 90 if (debug == 2) \ 91 printk(level fmt, ##args); \ 92 } while (0) 93 #else 94 #define tun_debug(level, tun, fmt, args...) \ 95 do { \ 96 if (0) \ 97 netdev_printk(level, tun->dev, fmt, ##args); \ 98 } while (0) 99 #define DBG1(level, fmt, args...) \ 100 do { \ 101 if (0) \ 102 printk(level fmt, ##args); \ 103 } while (0) 104 #endif 105 106 /* TUN device flags */ 107 108 /* IFF_ATTACH_QUEUE is never stored in device flags, 109 * overload it to mean fasync when stored there. 110 */ 111 #define TUN_FASYNC IFF_ATTACH_QUEUE 112 /* High bits in flags field are unused. */ 113 #define TUN_VNET_LE 0x80000000 114 115 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \ 116 IFF_MULTI_QUEUE) 117 #define GOODCOPY_LEN 128 118 119 #define FLT_EXACT_COUNT 8 120 struct tap_filter { 121 unsigned int count; /* Number of addrs. Zero means disabled */ 122 u32 mask[2]; /* Mask of the hashed addrs */ 123 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 124 }; 125 126 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal 127 * to max number of VCPUs in guest. */ 128 #define MAX_TAP_QUEUES 256 129 #define MAX_TAP_FLOWS 4096 130 131 #define TUN_FLOW_EXPIRE (3 * HZ) 132 133 /* A tun_file connects an open character device to a tuntap netdevice. It 134 * also contains all socket related structures (except sock_fprog and tap_filter) 135 * to serve as one transmit queue for tuntap device. The sock_fprog and 136 * tap_filter were kept in tun_struct since they were used for filtering for the 137 * netdevice not for a specific queue (at least I didn't see the requirement for 138 * this). 139 * 140 * RCU usage: 141 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 142 * other can only be read while rcu_read_lock or rtnl_lock is held. 143 */ 144 struct tun_file { 145 struct sock sk; 146 struct socket socket; 147 struct socket_wq wq; 148 struct tun_struct __rcu *tun; 149 struct net *net; 150 struct fasync_struct *fasync; 151 /* only used for fasnyc */ 152 unsigned int flags; 153 union { 154 u16 queue_index; 155 unsigned int ifindex; 156 }; 157 struct list_head next; 158 struct tun_struct *detached; 159 }; 160 161 struct tun_flow_entry { 162 struct hlist_node hash_link; 163 struct rcu_head rcu; 164 struct tun_struct *tun; 165 166 u32 rxhash; 167 u32 rps_rxhash; 168 int queue_index; 169 unsigned long updated; 170 }; 171 172 #define TUN_NUM_FLOW_ENTRIES 1024 173 174 /* Since the socket were moved to tun_file, to preserve the behavior of persist 175 * device, socket filter, sndbuf and vnet header size were restore when the 176 * file were attached to a persist device. 177 */ 178 struct tun_struct { 179 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 180 unsigned int numqueues; 181 unsigned int flags; 182 kuid_t owner; 183 kgid_t group; 184 185 struct net_device *dev; 186 netdev_features_t set_features; 187 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 188 NETIF_F_TSO6|NETIF_F_UFO) 189 190 int vnet_hdr_sz; 191 int sndbuf; 192 struct tap_filter txflt; 193 struct sock_fprog fprog; 194 /* protected by rtnl lock */ 195 bool filter_attached; 196 #ifdef TUN_DEBUG 197 int debug; 198 #endif 199 spinlock_t lock; 200 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 201 struct timer_list flow_gc_timer; 202 unsigned long ageing_time; 203 unsigned int numdisabled; 204 struct list_head disabled; 205 void *security; 206 u32 flow_count; 207 }; 208 209 static inline bool tun_is_little_endian(struct tun_struct *tun) 210 { 211 return tun->flags & TUN_VNET_LE; 212 } 213 214 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) 215 { 216 return __virtio16_to_cpu(tun_is_little_endian(tun), val); 217 } 218 219 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val) 220 { 221 return __cpu_to_virtio16(tun_is_little_endian(tun), val); 222 } 223 224 static inline u32 tun_hashfn(u32 rxhash) 225 { 226 return rxhash & 0x3ff; 227 } 228 229 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 230 { 231 struct tun_flow_entry *e; 232 233 hlist_for_each_entry_rcu(e, head, hash_link) { 234 if (e->rxhash == rxhash) 235 return e; 236 } 237 return NULL; 238 } 239 240 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 241 struct hlist_head *head, 242 u32 rxhash, u16 queue_index) 243 { 244 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 245 246 if (e) { 247 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 248 rxhash, queue_index); 249 e->updated = jiffies; 250 e->rxhash = rxhash; 251 e->rps_rxhash = 0; 252 e->queue_index = queue_index; 253 e->tun = tun; 254 hlist_add_head_rcu(&e->hash_link, head); 255 ++tun->flow_count; 256 } 257 return e; 258 } 259 260 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 261 { 262 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 263 e->rxhash, e->queue_index); 264 hlist_del_rcu(&e->hash_link); 265 kfree_rcu(e, rcu); 266 --tun->flow_count; 267 } 268 269 static void tun_flow_flush(struct tun_struct *tun) 270 { 271 int i; 272 273 spin_lock_bh(&tun->lock); 274 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 275 struct tun_flow_entry *e; 276 struct hlist_node *n; 277 278 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 279 tun_flow_delete(tun, e); 280 } 281 spin_unlock_bh(&tun->lock); 282 } 283 284 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 285 { 286 int i; 287 288 spin_lock_bh(&tun->lock); 289 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 290 struct tun_flow_entry *e; 291 struct hlist_node *n; 292 293 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 294 if (e->queue_index == queue_index) 295 tun_flow_delete(tun, e); 296 } 297 } 298 spin_unlock_bh(&tun->lock); 299 } 300 301 static void tun_flow_cleanup(unsigned long data) 302 { 303 struct tun_struct *tun = (struct tun_struct *)data; 304 unsigned long delay = tun->ageing_time; 305 unsigned long next_timer = jiffies + delay; 306 unsigned long count = 0; 307 int i; 308 309 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 310 311 spin_lock_bh(&tun->lock); 312 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 313 struct tun_flow_entry *e; 314 struct hlist_node *n; 315 316 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 317 unsigned long this_timer; 318 count++; 319 this_timer = e->updated + delay; 320 if (time_before_eq(this_timer, jiffies)) 321 tun_flow_delete(tun, e); 322 else if (time_before(this_timer, next_timer)) 323 next_timer = this_timer; 324 } 325 } 326 327 if (count) 328 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 329 spin_unlock_bh(&tun->lock); 330 } 331 332 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 333 struct tun_file *tfile) 334 { 335 struct hlist_head *head; 336 struct tun_flow_entry *e; 337 unsigned long delay = tun->ageing_time; 338 u16 queue_index = tfile->queue_index; 339 340 if (!rxhash) 341 return; 342 else 343 head = &tun->flows[tun_hashfn(rxhash)]; 344 345 rcu_read_lock(); 346 347 /* We may get a very small possibility of OOO during switching, not 348 * worth to optimize.*/ 349 if (tun->numqueues == 1 || tfile->detached) 350 goto unlock; 351 352 e = tun_flow_find(head, rxhash); 353 if (likely(e)) { 354 /* TODO: keep queueing to old queue until it's empty? */ 355 e->queue_index = queue_index; 356 e->updated = jiffies; 357 sock_rps_record_flow_hash(e->rps_rxhash); 358 } else { 359 spin_lock_bh(&tun->lock); 360 if (!tun_flow_find(head, rxhash) && 361 tun->flow_count < MAX_TAP_FLOWS) 362 tun_flow_create(tun, head, rxhash, queue_index); 363 364 if (!timer_pending(&tun->flow_gc_timer)) 365 mod_timer(&tun->flow_gc_timer, 366 round_jiffies_up(jiffies + delay)); 367 spin_unlock_bh(&tun->lock); 368 } 369 370 unlock: 371 rcu_read_unlock(); 372 } 373 374 /** 375 * Save the hash received in the stack receive path and update the 376 * flow_hash table accordingly. 377 */ 378 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 379 { 380 if (unlikely(e->rps_rxhash != hash)) 381 e->rps_rxhash = hash; 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 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1171 pr_debug("GSO!\n"); 1172 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1173 case VIRTIO_NET_HDR_GSO_TCPV4: 1174 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1175 break; 1176 case VIRTIO_NET_HDR_GSO_TCPV6: 1177 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1178 break; 1179 case VIRTIO_NET_HDR_GSO_UDP: 1180 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1181 break; 1182 default: 1183 tun->dev->stats.rx_frame_errors++; 1184 kfree_skb(skb); 1185 return -EINVAL; 1186 } 1187 1188 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1189 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1190 1191 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size); 1192 if (skb_shinfo(skb)->gso_size == 0) { 1193 tun->dev->stats.rx_frame_errors++; 1194 kfree_skb(skb); 1195 return -EINVAL; 1196 } 1197 1198 /* Header must be checked, and gso_segs computed. */ 1199 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1200 skb_shinfo(skb)->gso_segs = 0; 1201 } 1202 1203 /* copy skb_ubuf_info for callback when skb has no error */ 1204 if (zerocopy) { 1205 skb_shinfo(skb)->destructor_arg = msg_control; 1206 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1207 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1208 } 1209 1210 skb_reset_network_header(skb); 1211 skb_probe_transport_header(skb, 0); 1212 1213 rxhash = skb_get_hash(skb); 1214 netif_rx_ni(skb); 1215 1216 tun->dev->stats.rx_packets++; 1217 tun->dev->stats.rx_bytes += len; 1218 1219 tun_flow_update(tun, rxhash, tfile); 1220 return total_len; 1221 } 1222 1223 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from) 1224 { 1225 struct file *file = iocb->ki_filp; 1226 struct tun_struct *tun = tun_get(file); 1227 struct tun_file *tfile = file->private_data; 1228 ssize_t result; 1229 1230 if (!tun) 1231 return -EBADFD; 1232 1233 result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK); 1234 1235 tun_put(tun); 1236 return result; 1237 } 1238 1239 /* Put packet to the user space buffer */ 1240 static ssize_t tun_put_user(struct tun_struct *tun, 1241 struct tun_file *tfile, 1242 struct sk_buff *skb, 1243 struct iov_iter *iter) 1244 { 1245 struct tun_pi pi = { 0, skb->protocol }; 1246 ssize_t total; 1247 int vlan_offset = 0; 1248 int vlan_hlen = 0; 1249 int vnet_hdr_sz = 0; 1250 1251 if (skb_vlan_tag_present(skb)) 1252 vlan_hlen = VLAN_HLEN; 1253 1254 if (tun->flags & IFF_VNET_HDR) 1255 vnet_hdr_sz = tun->vnet_hdr_sz; 1256 1257 total = skb->len + vlan_hlen + vnet_hdr_sz; 1258 1259 if (!(tun->flags & IFF_NO_PI)) { 1260 if (iov_iter_count(iter) < sizeof(pi)) 1261 return -EINVAL; 1262 1263 total += sizeof(pi); 1264 if (iov_iter_count(iter) < total) { 1265 /* Packet will be striped */ 1266 pi.flags |= TUN_PKT_STRIP; 1267 } 1268 1269 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi)) 1270 return -EFAULT; 1271 } 1272 1273 if (vnet_hdr_sz) { 1274 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1275 if (iov_iter_count(iter) < vnet_hdr_sz) 1276 return -EINVAL; 1277 1278 if (skb_is_gso(skb)) { 1279 struct skb_shared_info *sinfo = skb_shinfo(skb); 1280 1281 /* This is a hint as to how much should be linear. */ 1282 gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb)); 1283 gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size); 1284 if (sinfo->gso_type & SKB_GSO_TCPV4) 1285 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1286 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1287 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1288 else if (sinfo->gso_type & SKB_GSO_UDP) 1289 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1290 else { 1291 pr_err("unexpected GSO type: " 1292 "0x%x, gso_size %d, hdr_len %d\n", 1293 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size), 1294 tun16_to_cpu(tun, gso.hdr_len)); 1295 print_hex_dump(KERN_ERR, "tun: ", 1296 DUMP_PREFIX_NONE, 1297 16, 1, skb->head, 1298 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true); 1299 WARN_ON_ONCE(1); 1300 return -EINVAL; 1301 } 1302 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1303 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1304 } else 1305 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1306 1307 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1308 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1309 gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) + 1310 vlan_hlen); 1311 gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset); 1312 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1313 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1314 } /* else everything is zero */ 1315 1316 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso)) 1317 return -EFAULT; 1318 1319 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso)); 1320 } 1321 1322 if (vlan_hlen) { 1323 int ret; 1324 struct { 1325 __be16 h_vlan_proto; 1326 __be16 h_vlan_TCI; 1327 } veth; 1328 1329 veth.h_vlan_proto = skb->vlan_proto; 1330 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb)); 1331 1332 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1333 1334 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset); 1335 if (ret || !iov_iter_count(iter)) 1336 goto done; 1337 1338 ret = copy_to_iter(&veth, sizeof(veth), iter); 1339 if (ret != sizeof(veth) || !iov_iter_count(iter)) 1340 goto done; 1341 } 1342 1343 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset); 1344 1345 done: 1346 tun->dev->stats.tx_packets++; 1347 tun->dev->stats.tx_bytes += skb->len + vlan_hlen; 1348 1349 return total; 1350 } 1351 1352 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1353 struct iov_iter *to, 1354 int noblock) 1355 { 1356 struct sk_buff *skb; 1357 ssize_t ret; 1358 int peeked, err, off = 0; 1359 1360 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1361 1362 if (!iov_iter_count(to)) 1363 return 0; 1364 1365 if (tun->dev->reg_state != NETREG_REGISTERED) 1366 return -EIO; 1367 1368 /* Read frames from queue */ 1369 skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0, 1370 &peeked, &off, &err); 1371 if (!skb) 1372 return err; 1373 1374 ret = tun_put_user(tun, tfile, skb, to); 1375 if (unlikely(ret < 0)) 1376 kfree_skb(skb); 1377 else 1378 consume_skb(skb); 1379 1380 return ret; 1381 } 1382 1383 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1384 { 1385 struct file *file = iocb->ki_filp; 1386 struct tun_file *tfile = file->private_data; 1387 struct tun_struct *tun = __tun_get(tfile); 1388 ssize_t len = iov_iter_count(to), ret; 1389 1390 if (!tun) 1391 return -EBADFD; 1392 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK); 1393 ret = min_t(ssize_t, ret, len); 1394 if (ret > 0) 1395 iocb->ki_pos = ret; 1396 tun_put(tun); 1397 return ret; 1398 } 1399 1400 static void tun_free_netdev(struct net_device *dev) 1401 { 1402 struct tun_struct *tun = netdev_priv(dev); 1403 1404 BUG_ON(!(list_empty(&tun->disabled))); 1405 tun_flow_uninit(tun); 1406 security_tun_dev_free_security(tun->security); 1407 free_netdev(dev); 1408 } 1409 1410 static void tun_setup(struct net_device *dev) 1411 { 1412 struct tun_struct *tun = netdev_priv(dev); 1413 1414 tun->owner = INVALID_UID; 1415 tun->group = INVALID_GID; 1416 1417 dev->ethtool_ops = &tun_ethtool_ops; 1418 dev->destructor = tun_free_netdev; 1419 } 1420 1421 /* Trivial set of netlink ops to allow deleting tun or tap 1422 * device with netlink. 1423 */ 1424 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1425 { 1426 return -EINVAL; 1427 } 1428 1429 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1430 .kind = DRV_NAME, 1431 .priv_size = sizeof(struct tun_struct), 1432 .setup = tun_setup, 1433 .validate = tun_validate, 1434 }; 1435 1436 static void tun_sock_write_space(struct sock *sk) 1437 { 1438 struct tun_file *tfile; 1439 wait_queue_head_t *wqueue; 1440 1441 if (!sock_writeable(sk)) 1442 return; 1443 1444 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1445 return; 1446 1447 wqueue = sk_sleep(sk); 1448 if (wqueue && waitqueue_active(wqueue)) 1449 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1450 POLLWRNORM | POLLWRBAND); 1451 1452 tfile = container_of(sk, struct tun_file, sk); 1453 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1454 } 1455 1456 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) 1457 { 1458 int ret; 1459 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1460 struct tun_struct *tun = __tun_get(tfile); 1461 1462 if (!tun) 1463 return -EBADFD; 1464 1465 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter, 1466 m->msg_flags & MSG_DONTWAIT); 1467 tun_put(tun); 1468 return ret; 1469 } 1470 1471 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, 1472 int flags) 1473 { 1474 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1475 struct tun_struct *tun = __tun_get(tfile); 1476 int ret; 1477 1478 if (!tun) 1479 return -EBADFD; 1480 1481 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1482 ret = -EINVAL; 1483 goto out; 1484 } 1485 if (flags & MSG_ERRQUEUE) { 1486 ret = sock_recv_errqueue(sock->sk, m, total_len, 1487 SOL_PACKET, TUN_TX_TIMESTAMP); 1488 goto out; 1489 } 1490 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT); 1491 if (ret > (ssize_t)total_len) { 1492 m->msg_flags |= MSG_TRUNC; 1493 ret = flags & MSG_TRUNC ? ret : total_len; 1494 } 1495 out: 1496 tun_put(tun); 1497 return ret; 1498 } 1499 1500 static int tun_release(struct socket *sock) 1501 { 1502 if (sock->sk) 1503 sock_put(sock->sk); 1504 return 0; 1505 } 1506 1507 /* Ops structure to mimic raw sockets with tun */ 1508 static const struct proto_ops tun_socket_ops = { 1509 .sendmsg = tun_sendmsg, 1510 .recvmsg = tun_recvmsg, 1511 .release = tun_release, 1512 }; 1513 1514 static struct proto tun_proto = { 1515 .name = "tun", 1516 .owner = THIS_MODULE, 1517 .obj_size = sizeof(struct tun_file), 1518 }; 1519 1520 static int tun_flags(struct tun_struct *tun) 1521 { 1522 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP); 1523 } 1524 1525 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1526 char *buf) 1527 { 1528 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1529 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1530 } 1531 1532 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1533 char *buf) 1534 { 1535 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1536 return uid_valid(tun->owner)? 1537 sprintf(buf, "%u\n", 1538 from_kuid_munged(current_user_ns(), tun->owner)): 1539 sprintf(buf, "-1\n"); 1540 } 1541 1542 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1543 char *buf) 1544 { 1545 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1546 return gid_valid(tun->group) ? 1547 sprintf(buf, "%u\n", 1548 from_kgid_munged(current_user_ns(), tun->group)): 1549 sprintf(buf, "-1\n"); 1550 } 1551 1552 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1553 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1554 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1555 1556 static struct attribute *tun_dev_attrs[] = { 1557 &dev_attr_tun_flags.attr, 1558 &dev_attr_owner.attr, 1559 &dev_attr_group.attr, 1560 NULL 1561 }; 1562 1563 static const struct attribute_group tun_attr_group = { 1564 .attrs = tun_dev_attrs 1565 }; 1566 1567 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1568 { 1569 struct tun_struct *tun; 1570 struct tun_file *tfile = file->private_data; 1571 struct net_device *dev; 1572 int err; 1573 1574 if (tfile->detached) 1575 return -EINVAL; 1576 1577 dev = __dev_get_by_name(net, ifr->ifr_name); 1578 if (dev) { 1579 if (ifr->ifr_flags & IFF_TUN_EXCL) 1580 return -EBUSY; 1581 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1582 tun = netdev_priv(dev); 1583 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1584 tun = netdev_priv(dev); 1585 else 1586 return -EINVAL; 1587 1588 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1589 !!(tun->flags & IFF_MULTI_QUEUE)) 1590 return -EINVAL; 1591 1592 if (tun_not_capable(tun)) 1593 return -EPERM; 1594 err = security_tun_dev_open(tun->security); 1595 if (err < 0) 1596 return err; 1597 1598 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1599 if (err < 0) 1600 return err; 1601 1602 if (tun->flags & IFF_MULTI_QUEUE && 1603 (tun->numqueues + tun->numdisabled > 1)) { 1604 /* One or more queue has already been attached, no need 1605 * to initialize the device again. 1606 */ 1607 return 0; 1608 } 1609 } 1610 else { 1611 char *name; 1612 unsigned long flags = 0; 1613 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1614 MAX_TAP_QUEUES : 1; 1615 1616 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1617 return -EPERM; 1618 err = security_tun_dev_create(); 1619 if (err < 0) 1620 return err; 1621 1622 /* Set dev type */ 1623 if (ifr->ifr_flags & IFF_TUN) { 1624 /* TUN device */ 1625 flags |= IFF_TUN; 1626 name = "tun%d"; 1627 } else if (ifr->ifr_flags & IFF_TAP) { 1628 /* TAP device */ 1629 flags |= IFF_TAP; 1630 name = "tap%d"; 1631 } else 1632 return -EINVAL; 1633 1634 if (*ifr->ifr_name) 1635 name = ifr->ifr_name; 1636 1637 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1638 NET_NAME_UNKNOWN, tun_setup, queues, 1639 queues); 1640 1641 if (!dev) 1642 return -ENOMEM; 1643 1644 dev_net_set(dev, net); 1645 dev->rtnl_link_ops = &tun_link_ops; 1646 dev->ifindex = tfile->ifindex; 1647 dev->sysfs_groups[0] = &tun_attr_group; 1648 1649 tun = netdev_priv(dev); 1650 tun->dev = dev; 1651 tun->flags = flags; 1652 tun->txflt.count = 0; 1653 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1654 1655 tun->filter_attached = false; 1656 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1657 1658 spin_lock_init(&tun->lock); 1659 1660 err = security_tun_dev_alloc_security(&tun->security); 1661 if (err < 0) 1662 goto err_free_dev; 1663 1664 tun_net_init(dev); 1665 tun_flow_init(tun); 1666 1667 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1668 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1669 NETIF_F_HW_VLAN_STAG_TX; 1670 dev->features = dev->hw_features; 1671 dev->vlan_features = dev->features & 1672 ~(NETIF_F_HW_VLAN_CTAG_TX | 1673 NETIF_F_HW_VLAN_STAG_TX); 1674 1675 INIT_LIST_HEAD(&tun->disabled); 1676 err = tun_attach(tun, file, false); 1677 if (err < 0) 1678 goto err_free_flow; 1679 1680 err = register_netdevice(tun->dev); 1681 if (err < 0) 1682 goto err_detach; 1683 } 1684 1685 netif_carrier_on(tun->dev); 1686 1687 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1688 1689 tun->flags = (tun->flags & ~TUN_FEATURES) | 1690 (ifr->ifr_flags & TUN_FEATURES); 1691 1692 /* Make sure persistent devices do not get stuck in 1693 * xoff state. 1694 */ 1695 if (netif_running(tun->dev)) 1696 netif_tx_wake_all_queues(tun->dev); 1697 1698 strcpy(ifr->ifr_name, tun->dev->name); 1699 return 0; 1700 1701 err_detach: 1702 tun_detach_all(dev); 1703 err_free_flow: 1704 tun_flow_uninit(tun); 1705 security_tun_dev_free_security(tun->security); 1706 err_free_dev: 1707 free_netdev(dev); 1708 return err; 1709 } 1710 1711 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1712 struct ifreq *ifr) 1713 { 1714 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1715 1716 strcpy(ifr->ifr_name, tun->dev->name); 1717 1718 ifr->ifr_flags = tun_flags(tun); 1719 1720 } 1721 1722 /* This is like a cut-down ethtool ops, except done via tun fd so no 1723 * privs required. */ 1724 static int set_offload(struct tun_struct *tun, unsigned long arg) 1725 { 1726 netdev_features_t features = 0; 1727 1728 if (arg & TUN_F_CSUM) { 1729 features |= NETIF_F_HW_CSUM; 1730 arg &= ~TUN_F_CSUM; 1731 1732 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1733 if (arg & TUN_F_TSO_ECN) { 1734 features |= NETIF_F_TSO_ECN; 1735 arg &= ~TUN_F_TSO_ECN; 1736 } 1737 if (arg & TUN_F_TSO4) 1738 features |= NETIF_F_TSO; 1739 if (arg & TUN_F_TSO6) 1740 features |= NETIF_F_TSO6; 1741 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1742 } 1743 1744 if (arg & TUN_F_UFO) { 1745 features |= NETIF_F_UFO; 1746 arg &= ~TUN_F_UFO; 1747 } 1748 } 1749 1750 /* This gives the user a way to test for new features in future by 1751 * trying to set them. */ 1752 if (arg) 1753 return -EINVAL; 1754 1755 tun->set_features = features; 1756 netdev_update_features(tun->dev); 1757 1758 return 0; 1759 } 1760 1761 static void tun_detach_filter(struct tun_struct *tun, int n) 1762 { 1763 int i; 1764 struct tun_file *tfile; 1765 1766 for (i = 0; i < n; i++) { 1767 tfile = rtnl_dereference(tun->tfiles[i]); 1768 sk_detach_filter(tfile->socket.sk); 1769 } 1770 1771 tun->filter_attached = false; 1772 } 1773 1774 static int tun_attach_filter(struct tun_struct *tun) 1775 { 1776 int i, ret = 0; 1777 struct tun_file *tfile; 1778 1779 for (i = 0; i < tun->numqueues; i++) { 1780 tfile = rtnl_dereference(tun->tfiles[i]); 1781 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1782 if (ret) { 1783 tun_detach_filter(tun, i); 1784 return ret; 1785 } 1786 } 1787 1788 tun->filter_attached = true; 1789 return ret; 1790 } 1791 1792 static void tun_set_sndbuf(struct tun_struct *tun) 1793 { 1794 struct tun_file *tfile; 1795 int i; 1796 1797 for (i = 0; i < tun->numqueues; i++) { 1798 tfile = rtnl_dereference(tun->tfiles[i]); 1799 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1800 } 1801 } 1802 1803 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1804 { 1805 struct tun_file *tfile = file->private_data; 1806 struct tun_struct *tun; 1807 int ret = 0; 1808 1809 rtnl_lock(); 1810 1811 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1812 tun = tfile->detached; 1813 if (!tun) { 1814 ret = -EINVAL; 1815 goto unlock; 1816 } 1817 ret = security_tun_dev_attach_queue(tun->security); 1818 if (ret < 0) 1819 goto unlock; 1820 ret = tun_attach(tun, file, false); 1821 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1822 tun = rtnl_dereference(tfile->tun); 1823 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached) 1824 ret = -EINVAL; 1825 else 1826 __tun_detach(tfile, false); 1827 } else 1828 ret = -EINVAL; 1829 1830 unlock: 1831 rtnl_unlock(); 1832 return ret; 1833 } 1834 1835 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1836 unsigned long arg, int ifreq_len) 1837 { 1838 struct tun_file *tfile = file->private_data; 1839 struct tun_struct *tun; 1840 void __user* argp = (void __user*)arg; 1841 struct ifreq ifr; 1842 kuid_t owner; 1843 kgid_t group; 1844 int sndbuf; 1845 int vnet_hdr_sz; 1846 unsigned int ifindex; 1847 int le; 1848 int ret; 1849 1850 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1851 if (copy_from_user(&ifr, argp, ifreq_len)) 1852 return -EFAULT; 1853 } else { 1854 memset(&ifr, 0, sizeof(ifr)); 1855 } 1856 if (cmd == TUNGETFEATURES) { 1857 /* Currently this just means: "what IFF flags are valid?". 1858 * This is needed because we never checked for invalid flags on 1859 * TUNSETIFF. 1860 */ 1861 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES, 1862 (unsigned int __user*)argp); 1863 } else if (cmd == TUNSETQUEUE) 1864 return tun_set_queue(file, &ifr); 1865 1866 ret = 0; 1867 rtnl_lock(); 1868 1869 tun = __tun_get(tfile); 1870 if (cmd == TUNSETIFF && !tun) { 1871 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1872 1873 ret = tun_set_iff(tfile->net, file, &ifr); 1874 1875 if (ret) 1876 goto unlock; 1877 1878 if (copy_to_user(argp, &ifr, ifreq_len)) 1879 ret = -EFAULT; 1880 goto unlock; 1881 } 1882 if (cmd == TUNSETIFINDEX) { 1883 ret = -EPERM; 1884 if (tun) 1885 goto unlock; 1886 1887 ret = -EFAULT; 1888 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1889 goto unlock; 1890 1891 ret = 0; 1892 tfile->ifindex = ifindex; 1893 goto unlock; 1894 } 1895 1896 ret = -EBADFD; 1897 if (!tun) 1898 goto unlock; 1899 1900 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1901 1902 ret = 0; 1903 switch (cmd) { 1904 case TUNGETIFF: 1905 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1906 1907 if (tfile->detached) 1908 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1909 if (!tfile->socket.sk->sk_filter) 1910 ifr.ifr_flags |= IFF_NOFILTER; 1911 1912 if (copy_to_user(argp, &ifr, ifreq_len)) 1913 ret = -EFAULT; 1914 break; 1915 1916 case TUNSETNOCSUM: 1917 /* Disable/Enable checksum */ 1918 1919 /* [unimplemented] */ 1920 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1921 arg ? "disabled" : "enabled"); 1922 break; 1923 1924 case TUNSETPERSIST: 1925 /* Disable/Enable persist mode. Keep an extra reference to the 1926 * module to prevent the module being unprobed. 1927 */ 1928 if (arg && !(tun->flags & IFF_PERSIST)) { 1929 tun->flags |= IFF_PERSIST; 1930 __module_get(THIS_MODULE); 1931 } 1932 if (!arg && (tun->flags & IFF_PERSIST)) { 1933 tun->flags &= ~IFF_PERSIST; 1934 module_put(THIS_MODULE); 1935 } 1936 1937 tun_debug(KERN_INFO, tun, "persist %s\n", 1938 arg ? "enabled" : "disabled"); 1939 break; 1940 1941 case TUNSETOWNER: 1942 /* Set owner of the device */ 1943 owner = make_kuid(current_user_ns(), arg); 1944 if (!uid_valid(owner)) { 1945 ret = -EINVAL; 1946 break; 1947 } 1948 tun->owner = owner; 1949 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1950 from_kuid(&init_user_ns, tun->owner)); 1951 break; 1952 1953 case TUNSETGROUP: 1954 /* Set group of the device */ 1955 group = make_kgid(current_user_ns(), arg); 1956 if (!gid_valid(group)) { 1957 ret = -EINVAL; 1958 break; 1959 } 1960 tun->group = group; 1961 tun_debug(KERN_INFO, tun, "group set to %u\n", 1962 from_kgid(&init_user_ns, tun->group)); 1963 break; 1964 1965 case TUNSETLINK: 1966 /* Only allow setting the type when the interface is down */ 1967 if (tun->dev->flags & IFF_UP) { 1968 tun_debug(KERN_INFO, tun, 1969 "Linktype set failed because interface is up\n"); 1970 ret = -EBUSY; 1971 } else { 1972 tun->dev->type = (int) arg; 1973 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1974 tun->dev->type); 1975 ret = 0; 1976 } 1977 break; 1978 1979 #ifdef TUN_DEBUG 1980 case TUNSETDEBUG: 1981 tun->debug = arg; 1982 break; 1983 #endif 1984 case TUNSETOFFLOAD: 1985 ret = set_offload(tun, arg); 1986 break; 1987 1988 case TUNSETTXFILTER: 1989 /* Can be set only for TAPs */ 1990 ret = -EINVAL; 1991 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 1992 break; 1993 ret = update_filter(&tun->txflt, (void __user *)arg); 1994 break; 1995 1996 case SIOCGIFHWADDR: 1997 /* Get hw address */ 1998 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 1999 ifr.ifr_hwaddr.sa_family = tun->dev->type; 2000 if (copy_to_user(argp, &ifr, ifreq_len)) 2001 ret = -EFAULT; 2002 break; 2003 2004 case SIOCSIFHWADDR: 2005 /* Set hw address */ 2006 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 2007 ifr.ifr_hwaddr.sa_data); 2008 2009 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2010 break; 2011 2012 case TUNGETSNDBUF: 2013 sndbuf = tfile->socket.sk->sk_sndbuf; 2014 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2015 ret = -EFAULT; 2016 break; 2017 2018 case TUNSETSNDBUF: 2019 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2020 ret = -EFAULT; 2021 break; 2022 } 2023 2024 tun->sndbuf = sndbuf; 2025 tun_set_sndbuf(tun); 2026 break; 2027 2028 case TUNGETVNETHDRSZ: 2029 vnet_hdr_sz = tun->vnet_hdr_sz; 2030 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2031 ret = -EFAULT; 2032 break; 2033 2034 case TUNSETVNETHDRSZ: 2035 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2036 ret = -EFAULT; 2037 break; 2038 } 2039 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2040 ret = -EINVAL; 2041 break; 2042 } 2043 2044 tun->vnet_hdr_sz = vnet_hdr_sz; 2045 break; 2046 2047 case TUNGETVNETLE: 2048 le = !!(tun->flags & TUN_VNET_LE); 2049 if (put_user(le, (int __user *)argp)) 2050 ret = -EFAULT; 2051 break; 2052 2053 case TUNSETVNETLE: 2054 if (get_user(le, (int __user *)argp)) { 2055 ret = -EFAULT; 2056 break; 2057 } 2058 if (le) 2059 tun->flags |= TUN_VNET_LE; 2060 else 2061 tun->flags &= ~TUN_VNET_LE; 2062 break; 2063 2064 case TUNATTACHFILTER: 2065 /* Can be set only for TAPs */ 2066 ret = -EINVAL; 2067 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2068 break; 2069 ret = -EFAULT; 2070 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2071 break; 2072 2073 ret = tun_attach_filter(tun); 2074 break; 2075 2076 case TUNDETACHFILTER: 2077 /* Can be set only for TAPs */ 2078 ret = -EINVAL; 2079 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2080 break; 2081 ret = 0; 2082 tun_detach_filter(tun, tun->numqueues); 2083 break; 2084 2085 case TUNGETFILTER: 2086 ret = -EINVAL; 2087 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2088 break; 2089 ret = -EFAULT; 2090 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2091 break; 2092 ret = 0; 2093 break; 2094 2095 default: 2096 ret = -EINVAL; 2097 break; 2098 } 2099 2100 unlock: 2101 rtnl_unlock(); 2102 if (tun) 2103 tun_put(tun); 2104 return ret; 2105 } 2106 2107 static long tun_chr_ioctl(struct file *file, 2108 unsigned int cmd, unsigned long arg) 2109 { 2110 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2111 } 2112 2113 #ifdef CONFIG_COMPAT 2114 static long tun_chr_compat_ioctl(struct file *file, 2115 unsigned int cmd, unsigned long arg) 2116 { 2117 switch (cmd) { 2118 case TUNSETIFF: 2119 case TUNGETIFF: 2120 case TUNSETTXFILTER: 2121 case TUNGETSNDBUF: 2122 case TUNSETSNDBUF: 2123 case SIOCGIFHWADDR: 2124 case SIOCSIFHWADDR: 2125 arg = (unsigned long)compat_ptr(arg); 2126 break; 2127 default: 2128 arg = (compat_ulong_t)arg; 2129 break; 2130 } 2131 2132 /* 2133 * compat_ifreq is shorter than ifreq, so we must not access beyond 2134 * the end of that structure. All fields that are used in this 2135 * driver are compatible though, we don't need to convert the 2136 * contents. 2137 */ 2138 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2139 } 2140 #endif /* CONFIG_COMPAT */ 2141 2142 static int tun_chr_fasync(int fd, struct file *file, int on) 2143 { 2144 struct tun_file *tfile = file->private_data; 2145 int ret; 2146 2147 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2148 goto out; 2149 2150 if (on) { 2151 __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2152 tfile->flags |= TUN_FASYNC; 2153 } else 2154 tfile->flags &= ~TUN_FASYNC; 2155 ret = 0; 2156 out: 2157 return ret; 2158 } 2159 2160 static int tun_chr_open(struct inode *inode, struct file * file) 2161 { 2162 struct tun_file *tfile; 2163 2164 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2165 2166 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2167 &tun_proto); 2168 if (!tfile) 2169 return -ENOMEM; 2170 RCU_INIT_POINTER(tfile->tun, NULL); 2171 tfile->net = get_net(current->nsproxy->net_ns); 2172 tfile->flags = 0; 2173 tfile->ifindex = 0; 2174 2175 init_waitqueue_head(&tfile->wq.wait); 2176 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq); 2177 2178 tfile->socket.file = file; 2179 tfile->socket.ops = &tun_socket_ops; 2180 2181 sock_init_data(&tfile->socket, &tfile->sk); 2182 sk_change_net(&tfile->sk, tfile->net); 2183 2184 tfile->sk.sk_write_space = tun_sock_write_space; 2185 tfile->sk.sk_sndbuf = INT_MAX; 2186 2187 file->private_data = tfile; 2188 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2189 INIT_LIST_HEAD(&tfile->next); 2190 2191 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2192 2193 return 0; 2194 } 2195 2196 static int tun_chr_close(struct inode *inode, struct file *file) 2197 { 2198 struct tun_file *tfile = file->private_data; 2199 struct net *net = tfile->net; 2200 2201 tun_detach(tfile, true); 2202 put_net(net); 2203 2204 return 0; 2205 } 2206 2207 #ifdef CONFIG_PROC_FS 2208 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f) 2209 { 2210 struct tun_struct *tun; 2211 struct ifreq ifr; 2212 2213 memset(&ifr, 0, sizeof(ifr)); 2214 2215 rtnl_lock(); 2216 tun = tun_get(f); 2217 if (tun) 2218 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 2219 rtnl_unlock(); 2220 2221 if (tun) 2222 tun_put(tun); 2223 2224 seq_printf(m, "iff:\t%s\n", ifr.ifr_name); 2225 } 2226 #endif 2227 2228 static const struct file_operations tun_fops = { 2229 .owner = THIS_MODULE, 2230 .llseek = no_llseek, 2231 .read_iter = tun_chr_read_iter, 2232 .write_iter = tun_chr_write_iter, 2233 .poll = tun_chr_poll, 2234 .unlocked_ioctl = tun_chr_ioctl, 2235 #ifdef CONFIG_COMPAT 2236 .compat_ioctl = tun_chr_compat_ioctl, 2237 #endif 2238 .open = tun_chr_open, 2239 .release = tun_chr_close, 2240 .fasync = tun_chr_fasync, 2241 #ifdef CONFIG_PROC_FS 2242 .show_fdinfo = tun_chr_show_fdinfo, 2243 #endif 2244 }; 2245 2246 static struct miscdevice tun_miscdev = { 2247 .minor = TUN_MINOR, 2248 .name = "tun", 2249 .nodename = "net/tun", 2250 .fops = &tun_fops, 2251 }; 2252 2253 /* ethtool interface */ 2254 2255 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2256 { 2257 cmd->supported = 0; 2258 cmd->advertising = 0; 2259 ethtool_cmd_speed_set(cmd, SPEED_10); 2260 cmd->duplex = DUPLEX_FULL; 2261 cmd->port = PORT_TP; 2262 cmd->phy_address = 0; 2263 cmd->transceiver = XCVR_INTERNAL; 2264 cmd->autoneg = AUTONEG_DISABLE; 2265 cmd->maxtxpkt = 0; 2266 cmd->maxrxpkt = 0; 2267 return 0; 2268 } 2269 2270 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2271 { 2272 struct tun_struct *tun = netdev_priv(dev); 2273 2274 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2275 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2276 2277 switch (tun->flags & TUN_TYPE_MASK) { 2278 case IFF_TUN: 2279 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2280 break; 2281 case IFF_TAP: 2282 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2283 break; 2284 } 2285 } 2286 2287 static u32 tun_get_msglevel(struct net_device *dev) 2288 { 2289 #ifdef TUN_DEBUG 2290 struct tun_struct *tun = netdev_priv(dev); 2291 return tun->debug; 2292 #else 2293 return -EOPNOTSUPP; 2294 #endif 2295 } 2296 2297 static void tun_set_msglevel(struct net_device *dev, u32 value) 2298 { 2299 #ifdef TUN_DEBUG 2300 struct tun_struct *tun = netdev_priv(dev); 2301 tun->debug = value; 2302 #endif 2303 } 2304 2305 static const struct ethtool_ops tun_ethtool_ops = { 2306 .get_settings = tun_get_settings, 2307 .get_drvinfo = tun_get_drvinfo, 2308 .get_msglevel = tun_get_msglevel, 2309 .set_msglevel = tun_set_msglevel, 2310 .get_link = ethtool_op_get_link, 2311 .get_ts_info = ethtool_op_get_ts_info, 2312 }; 2313 2314 2315 static int __init tun_init(void) 2316 { 2317 int ret = 0; 2318 2319 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2320 pr_info("%s\n", DRV_COPYRIGHT); 2321 2322 ret = rtnl_link_register(&tun_link_ops); 2323 if (ret) { 2324 pr_err("Can't register link_ops\n"); 2325 goto err_linkops; 2326 } 2327 2328 ret = misc_register(&tun_miscdev); 2329 if (ret) { 2330 pr_err("Can't register misc device %d\n", TUN_MINOR); 2331 goto err_misc; 2332 } 2333 return 0; 2334 err_misc: 2335 rtnl_link_unregister(&tun_link_ops); 2336 err_linkops: 2337 return ret; 2338 } 2339 2340 static void tun_cleanup(void) 2341 { 2342 misc_deregister(&tun_miscdev); 2343 rtnl_link_unregister(&tun_link_ops); 2344 } 2345 2346 /* Get an underlying socket object from tun file. Returns error unless file is 2347 * attached to a device. The returned object works like a packet socket, it 2348 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2349 * holding a reference to the file for as long as the socket is in use. */ 2350 struct socket *tun_get_socket(struct file *file) 2351 { 2352 struct tun_file *tfile; 2353 if (file->f_op != &tun_fops) 2354 return ERR_PTR(-EINVAL); 2355 tfile = file->private_data; 2356 if (!tfile) 2357 return ERR_PTR(-EBADFD); 2358 return &tfile->socket; 2359 } 2360 EXPORT_SYMBOL_GPL(tun_get_socket); 2361 2362 module_init(tun_init); 2363 module_exit(tun_cleanup); 2364 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2365 MODULE_AUTHOR(DRV_COPYRIGHT); 2366 MODULE_LICENSE("GPL"); 2367 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2368 MODULE_ALIAS("devname:net/tun"); 2369