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 74 #include <asm/uaccess.h> 75 76 /* Uncomment to enable debugging */ 77 /* #define TUN_DEBUG 1 */ 78 79 #ifdef TUN_DEBUG 80 static int debug; 81 82 #define tun_debug(level, tun, fmt, args...) \ 83 do { \ 84 if (tun->debug) \ 85 netdev_printk(level, tun->dev, fmt, ##args); \ 86 } while (0) 87 #define DBG1(level, fmt, args...) \ 88 do { \ 89 if (debug == 2) \ 90 printk(level fmt, ##args); \ 91 } while (0) 92 #else 93 #define tun_debug(level, tun, fmt, args...) \ 94 do { \ 95 if (0) \ 96 netdev_printk(level, tun->dev, fmt, ##args); \ 97 } while (0) 98 #define DBG1(level, fmt, args...) \ 99 do { \ 100 if (0) \ 101 printk(level fmt, ##args); \ 102 } while (0) 103 #endif 104 105 #define GOODCOPY_LEN 128 106 107 #define FLT_EXACT_COUNT 8 108 struct tap_filter { 109 unsigned int count; /* Number of addrs. Zero means disabled */ 110 u32 mask[2]; /* Mask of the hashed addrs */ 111 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 112 }; 113 114 /* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for 115 * the netdevice to be fit in one page. So we can make sure the success of 116 * memory allocation. TODO: increase the limit. */ 117 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES 118 #define MAX_TAP_FLOWS 4096 119 120 #define TUN_FLOW_EXPIRE (3 * HZ) 121 122 /* A tun_file connects an open character device to a tuntap netdevice. It 123 * also contains all socket related structures (except sock_fprog and tap_filter) 124 * to serve as one transmit queue for tuntap device. The sock_fprog and 125 * tap_filter were kept in tun_struct since they were used for filtering for the 126 * netdevice not for a specific queue (at least I didn't see the requirement for 127 * this). 128 * 129 * RCU usage: 130 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 131 * other can only be read while rcu_read_lock or rtnl_lock is held. 132 */ 133 struct tun_file { 134 struct sock sk; 135 struct socket socket; 136 struct socket_wq wq; 137 struct tun_struct __rcu *tun; 138 struct net *net; 139 struct fasync_struct *fasync; 140 /* only used for fasnyc */ 141 unsigned int flags; 142 union { 143 u16 queue_index; 144 unsigned int ifindex; 145 }; 146 struct list_head next; 147 struct tun_struct *detached; 148 }; 149 150 struct tun_flow_entry { 151 struct hlist_node hash_link; 152 struct rcu_head rcu; 153 struct tun_struct *tun; 154 155 u32 rxhash; 156 u32 rps_rxhash; 157 int queue_index; 158 unsigned long updated; 159 }; 160 161 #define TUN_NUM_FLOW_ENTRIES 1024 162 163 /* Since the socket were moved to tun_file, to preserve the behavior of persist 164 * device, socket filter, sndbuf and vnet header size were restore when the 165 * file were attached to a persist device. 166 */ 167 struct tun_struct { 168 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 169 unsigned int numqueues; 170 unsigned int flags; 171 kuid_t owner; 172 kgid_t group; 173 174 struct net_device *dev; 175 netdev_features_t set_features; 176 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 177 NETIF_F_TSO6|NETIF_F_UFO) 178 179 int vnet_hdr_sz; 180 int sndbuf; 181 struct tap_filter txflt; 182 struct sock_fprog fprog; 183 /* protected by rtnl lock */ 184 bool filter_attached; 185 #ifdef TUN_DEBUG 186 int debug; 187 #endif 188 spinlock_t lock; 189 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 190 struct timer_list flow_gc_timer; 191 unsigned long ageing_time; 192 unsigned int numdisabled; 193 struct list_head disabled; 194 void *security; 195 u32 flow_count; 196 }; 197 198 static inline u32 tun_hashfn(u32 rxhash) 199 { 200 return rxhash & 0x3ff; 201 } 202 203 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 204 { 205 struct tun_flow_entry *e; 206 207 hlist_for_each_entry_rcu(e, head, hash_link) { 208 if (e->rxhash == rxhash) 209 return e; 210 } 211 return NULL; 212 } 213 214 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 215 struct hlist_head *head, 216 u32 rxhash, u16 queue_index) 217 { 218 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 219 220 if (e) { 221 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 222 rxhash, queue_index); 223 e->updated = jiffies; 224 e->rxhash = rxhash; 225 e->rps_rxhash = 0; 226 e->queue_index = queue_index; 227 e->tun = tun; 228 hlist_add_head_rcu(&e->hash_link, head); 229 ++tun->flow_count; 230 } 231 return e; 232 } 233 234 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 235 { 236 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 237 e->rxhash, e->queue_index); 238 sock_rps_reset_flow_hash(e->rps_rxhash); 239 hlist_del_rcu(&e->hash_link); 240 kfree_rcu(e, rcu); 241 --tun->flow_count; 242 } 243 244 static void tun_flow_flush(struct tun_struct *tun) 245 { 246 int i; 247 248 spin_lock_bh(&tun->lock); 249 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 250 struct tun_flow_entry *e; 251 struct hlist_node *n; 252 253 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 254 tun_flow_delete(tun, e); 255 } 256 spin_unlock_bh(&tun->lock); 257 } 258 259 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 260 { 261 int i; 262 263 spin_lock_bh(&tun->lock); 264 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 265 struct tun_flow_entry *e; 266 struct hlist_node *n; 267 268 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 269 if (e->queue_index == queue_index) 270 tun_flow_delete(tun, e); 271 } 272 } 273 spin_unlock_bh(&tun->lock); 274 } 275 276 static void tun_flow_cleanup(unsigned long data) 277 { 278 struct tun_struct *tun = (struct tun_struct *)data; 279 unsigned long delay = tun->ageing_time; 280 unsigned long next_timer = jiffies + delay; 281 unsigned long count = 0; 282 int i; 283 284 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 285 286 spin_lock_bh(&tun->lock); 287 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 288 struct tun_flow_entry *e; 289 struct hlist_node *n; 290 291 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 292 unsigned long this_timer; 293 count++; 294 this_timer = e->updated + delay; 295 if (time_before_eq(this_timer, jiffies)) 296 tun_flow_delete(tun, e); 297 else if (time_before(this_timer, next_timer)) 298 next_timer = this_timer; 299 } 300 } 301 302 if (count) 303 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 304 spin_unlock_bh(&tun->lock); 305 } 306 307 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 308 struct tun_file *tfile) 309 { 310 struct hlist_head *head; 311 struct tun_flow_entry *e; 312 unsigned long delay = tun->ageing_time; 313 u16 queue_index = tfile->queue_index; 314 315 if (!rxhash) 316 return; 317 else 318 head = &tun->flows[tun_hashfn(rxhash)]; 319 320 rcu_read_lock(); 321 322 /* We may get a very small possibility of OOO during switching, not 323 * worth to optimize.*/ 324 if (tun->numqueues == 1 || tfile->detached) 325 goto unlock; 326 327 e = tun_flow_find(head, rxhash); 328 if (likely(e)) { 329 /* TODO: keep queueing to old queue until it's empty? */ 330 e->queue_index = queue_index; 331 e->updated = jiffies; 332 sock_rps_record_flow_hash(e->rps_rxhash); 333 } else { 334 spin_lock_bh(&tun->lock); 335 if (!tun_flow_find(head, rxhash) && 336 tun->flow_count < MAX_TAP_FLOWS) 337 tun_flow_create(tun, head, rxhash, queue_index); 338 339 if (!timer_pending(&tun->flow_gc_timer)) 340 mod_timer(&tun->flow_gc_timer, 341 round_jiffies_up(jiffies + delay)); 342 spin_unlock_bh(&tun->lock); 343 } 344 345 unlock: 346 rcu_read_unlock(); 347 } 348 349 /** 350 * Save the hash received in the stack receive path and update the 351 * flow_hash table accordingly. 352 */ 353 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 354 { 355 if (unlikely(e->rps_rxhash != hash)) { 356 sock_rps_reset_flow_hash(e->rps_rxhash); 357 e->rps_rxhash = hash; 358 } 359 } 360 361 /* We try to identify a flow through its rxhash first. The reason that 362 * we do not check rxq no. is because some cards(e.g 82599), chooses 363 * the rxq based on the txq where the last packet of the flow comes. As 364 * the userspace application move between processors, we may get a 365 * different rxq no. here. If we could not get rxhash, then we would 366 * hope the rxq no. may help here. 367 */ 368 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, 369 void *accel_priv, select_queue_fallback_t fallback) 370 { 371 struct tun_struct *tun = netdev_priv(dev); 372 struct tun_flow_entry *e; 373 u32 txq = 0; 374 u32 numqueues = 0; 375 376 rcu_read_lock(); 377 numqueues = ACCESS_ONCE(tun->numqueues); 378 379 txq = skb_get_hash(skb); 380 if (txq) { 381 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 382 if (e) { 383 tun_flow_save_rps_rxhash(e, txq); 384 txq = e->queue_index; 385 } else 386 /* use multiply and shift instead of expensive divide */ 387 txq = ((u64)txq * numqueues) >> 32; 388 } else if (likely(skb_rx_queue_recorded(skb))) { 389 txq = skb_get_rx_queue(skb); 390 while (unlikely(txq >= numqueues)) 391 txq -= numqueues; 392 } 393 394 rcu_read_unlock(); 395 return txq; 396 } 397 398 static inline bool tun_not_capable(struct tun_struct *tun) 399 { 400 const struct cred *cred = current_cred(); 401 struct net *net = dev_net(tun->dev); 402 403 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 404 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 405 !ns_capable(net->user_ns, CAP_NET_ADMIN); 406 } 407 408 static void tun_set_real_num_queues(struct tun_struct *tun) 409 { 410 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 411 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 412 } 413 414 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 415 { 416 tfile->detached = tun; 417 list_add_tail(&tfile->next, &tun->disabled); 418 ++tun->numdisabled; 419 } 420 421 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 422 { 423 struct tun_struct *tun = tfile->detached; 424 425 tfile->detached = NULL; 426 list_del_init(&tfile->next); 427 --tun->numdisabled; 428 return tun; 429 } 430 431 static void tun_queue_purge(struct tun_file *tfile) 432 { 433 skb_queue_purge(&tfile->sk.sk_receive_queue); 434 skb_queue_purge(&tfile->sk.sk_error_queue); 435 } 436 437 static void __tun_detach(struct tun_file *tfile, bool clean) 438 { 439 struct tun_file *ntfile; 440 struct tun_struct *tun; 441 442 tun = rtnl_dereference(tfile->tun); 443 444 if (tun && !tfile->detached) { 445 u16 index = tfile->queue_index; 446 BUG_ON(index >= tun->numqueues); 447 448 rcu_assign_pointer(tun->tfiles[index], 449 tun->tfiles[tun->numqueues - 1]); 450 ntfile = rtnl_dereference(tun->tfiles[index]); 451 ntfile->queue_index = index; 452 453 --tun->numqueues; 454 if (clean) { 455 RCU_INIT_POINTER(tfile->tun, NULL); 456 sock_put(&tfile->sk); 457 } else 458 tun_disable_queue(tun, tfile); 459 460 synchronize_net(); 461 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 462 /* Drop read queue */ 463 tun_queue_purge(tfile); 464 tun_set_real_num_queues(tun); 465 } else if (tfile->detached && clean) { 466 tun = tun_enable_queue(tfile); 467 sock_put(&tfile->sk); 468 } 469 470 if (clean) { 471 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 472 netif_carrier_off(tun->dev); 473 474 if (!(tun->flags & TUN_PERSIST) && 475 tun->dev->reg_state == NETREG_REGISTERED) 476 unregister_netdevice(tun->dev); 477 } 478 479 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 480 &tfile->socket.flags)); 481 sk_release_kernel(&tfile->sk); 482 } 483 } 484 485 static void tun_detach(struct tun_file *tfile, bool clean) 486 { 487 rtnl_lock(); 488 __tun_detach(tfile, clean); 489 rtnl_unlock(); 490 } 491 492 static void tun_detach_all(struct net_device *dev) 493 { 494 struct tun_struct *tun = netdev_priv(dev); 495 struct tun_file *tfile, *tmp; 496 int i, n = tun->numqueues; 497 498 for (i = 0; i < n; i++) { 499 tfile = rtnl_dereference(tun->tfiles[i]); 500 BUG_ON(!tfile); 501 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 502 RCU_INIT_POINTER(tfile->tun, NULL); 503 --tun->numqueues; 504 } 505 list_for_each_entry(tfile, &tun->disabled, next) { 506 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 507 RCU_INIT_POINTER(tfile->tun, NULL); 508 } 509 BUG_ON(tun->numqueues != 0); 510 511 synchronize_net(); 512 for (i = 0; i < n; i++) { 513 tfile = rtnl_dereference(tun->tfiles[i]); 514 /* Drop read queue */ 515 tun_queue_purge(tfile); 516 sock_put(&tfile->sk); 517 } 518 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 519 tun_enable_queue(tfile); 520 tun_queue_purge(tfile); 521 sock_put(&tfile->sk); 522 } 523 BUG_ON(tun->numdisabled != 0); 524 525 if (tun->flags & TUN_PERSIST) 526 module_put(THIS_MODULE); 527 } 528 529 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) 530 { 531 struct tun_file *tfile = file->private_data; 532 int err; 533 534 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 535 if (err < 0) 536 goto out; 537 538 err = -EINVAL; 539 if (rtnl_dereference(tfile->tun) && !tfile->detached) 540 goto out; 541 542 err = -EBUSY; 543 if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1) 544 goto out; 545 546 err = -E2BIG; 547 if (!tfile->detached && 548 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 549 goto out; 550 551 err = 0; 552 553 /* Re-attach the filter to persist device */ 554 if (!skip_filter && (tun->filter_attached == true)) { 555 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 556 if (!err) 557 goto out; 558 } 559 tfile->queue_index = tun->numqueues; 560 rcu_assign_pointer(tfile->tun, tun); 561 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 562 tun->numqueues++; 563 564 if (tfile->detached) 565 tun_enable_queue(tfile); 566 else 567 sock_hold(&tfile->sk); 568 569 tun_set_real_num_queues(tun); 570 571 /* device is allowed to go away first, so no need to hold extra 572 * refcnt. 573 */ 574 575 out: 576 return err; 577 } 578 579 static struct tun_struct *__tun_get(struct tun_file *tfile) 580 { 581 struct tun_struct *tun; 582 583 rcu_read_lock(); 584 tun = rcu_dereference(tfile->tun); 585 if (tun) 586 dev_hold(tun->dev); 587 rcu_read_unlock(); 588 589 return tun; 590 } 591 592 static struct tun_struct *tun_get(struct file *file) 593 { 594 return __tun_get(file->private_data); 595 } 596 597 static void tun_put(struct tun_struct *tun) 598 { 599 dev_put(tun->dev); 600 } 601 602 /* TAP filtering */ 603 static void addr_hash_set(u32 *mask, const u8 *addr) 604 { 605 int n = ether_crc(ETH_ALEN, addr) >> 26; 606 mask[n >> 5] |= (1 << (n & 31)); 607 } 608 609 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 610 { 611 int n = ether_crc(ETH_ALEN, addr) >> 26; 612 return mask[n >> 5] & (1 << (n & 31)); 613 } 614 615 static int update_filter(struct tap_filter *filter, void __user *arg) 616 { 617 struct { u8 u[ETH_ALEN]; } *addr; 618 struct tun_filter uf; 619 int err, alen, n, nexact; 620 621 if (copy_from_user(&uf, arg, sizeof(uf))) 622 return -EFAULT; 623 624 if (!uf.count) { 625 /* Disabled */ 626 filter->count = 0; 627 return 0; 628 } 629 630 alen = ETH_ALEN * uf.count; 631 addr = kmalloc(alen, GFP_KERNEL); 632 if (!addr) 633 return -ENOMEM; 634 635 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 636 err = -EFAULT; 637 goto done; 638 } 639 640 /* The filter is updated without holding any locks. Which is 641 * perfectly safe. We disable it first and in the worst 642 * case we'll accept a few undesired packets. */ 643 filter->count = 0; 644 wmb(); 645 646 /* Use first set of addresses as an exact filter */ 647 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 648 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 649 650 nexact = n; 651 652 /* Remaining multicast addresses are hashed, 653 * unicast will leave the filter disabled. */ 654 memset(filter->mask, 0, sizeof(filter->mask)); 655 for (; n < uf.count; n++) { 656 if (!is_multicast_ether_addr(addr[n].u)) { 657 err = 0; /* no filter */ 658 goto done; 659 } 660 addr_hash_set(filter->mask, addr[n].u); 661 } 662 663 /* For ALLMULTI just set the mask to all ones. 664 * This overrides the mask populated above. */ 665 if ((uf.flags & TUN_FLT_ALLMULTI)) 666 memset(filter->mask, ~0, sizeof(filter->mask)); 667 668 /* Now enable the filter */ 669 wmb(); 670 filter->count = nexact; 671 672 /* Return the number of exact filters */ 673 err = nexact; 674 675 done: 676 kfree(addr); 677 return err; 678 } 679 680 /* Returns: 0 - drop, !=0 - accept */ 681 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 682 { 683 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 684 * at this point. */ 685 struct ethhdr *eh = (struct ethhdr *) skb->data; 686 int i; 687 688 /* Exact match */ 689 for (i = 0; i < filter->count; i++) 690 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 691 return 1; 692 693 /* Inexact match (multicast only) */ 694 if (is_multicast_ether_addr(eh->h_dest)) 695 return addr_hash_test(filter->mask, eh->h_dest); 696 697 return 0; 698 } 699 700 /* 701 * Checks whether the packet is accepted or not. 702 * Returns: 0 - drop, !=0 - accept 703 */ 704 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 705 { 706 if (!filter->count) 707 return 1; 708 709 return run_filter(filter, skb); 710 } 711 712 /* Network device part of the driver */ 713 714 static const struct ethtool_ops tun_ethtool_ops; 715 716 /* Net device detach from fd. */ 717 static void tun_net_uninit(struct net_device *dev) 718 { 719 tun_detach_all(dev); 720 } 721 722 /* Net device open. */ 723 static int tun_net_open(struct net_device *dev) 724 { 725 netif_tx_start_all_queues(dev); 726 return 0; 727 } 728 729 /* Net device close. */ 730 static int tun_net_close(struct net_device *dev) 731 { 732 netif_tx_stop_all_queues(dev); 733 return 0; 734 } 735 736 /* Net device start xmit */ 737 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 738 { 739 struct tun_struct *tun = netdev_priv(dev); 740 int txq = skb->queue_mapping; 741 struct tun_file *tfile; 742 u32 numqueues = 0; 743 744 rcu_read_lock(); 745 tfile = rcu_dereference(tun->tfiles[txq]); 746 numqueues = ACCESS_ONCE(tun->numqueues); 747 748 /* Drop packet if interface is not attached */ 749 if (txq >= numqueues) 750 goto drop; 751 752 if (numqueues == 1) { 753 /* Select queue was not called for the skbuff, so we extract the 754 * RPS hash and save it into the flow_table here. 755 */ 756 __u32 rxhash; 757 758 rxhash = skb_get_hash(skb); 759 if (rxhash) { 760 struct tun_flow_entry *e; 761 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], 762 rxhash); 763 if (e) 764 tun_flow_save_rps_rxhash(e, rxhash); 765 } 766 } 767 768 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 769 770 BUG_ON(!tfile); 771 772 /* Drop if the filter does not like it. 773 * This is a noop if the filter is disabled. 774 * Filter can be enabled only for the TAP devices. */ 775 if (!check_filter(&tun->txflt, skb)) 776 goto drop; 777 778 if (tfile->socket.sk->sk_filter && 779 sk_filter(tfile->socket.sk, skb)) 780 goto drop; 781 782 /* Limit the number of packets queued by dividing txq length with the 783 * number of queues. 784 */ 785 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues 786 >= dev->tx_queue_len) 787 goto drop; 788 789 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 790 goto drop; 791 792 if (skb->sk) { 793 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags); 794 sw_tx_timestamp(skb); 795 } 796 797 /* Orphan the skb - required as we might hang on to it 798 * for indefinite time. 799 */ 800 skb_orphan(skb); 801 802 nf_reset(skb); 803 804 /* Enqueue packet */ 805 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 806 807 /* Notify and wake up reader process */ 808 if (tfile->flags & TUN_FASYNC) 809 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 810 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 811 812 rcu_read_unlock(); 813 return NETDEV_TX_OK; 814 815 drop: 816 dev->stats.tx_dropped++; 817 skb_tx_error(skb); 818 kfree_skb(skb); 819 rcu_read_unlock(); 820 return NETDEV_TX_OK; 821 } 822 823 static void tun_net_mclist(struct net_device *dev) 824 { 825 /* 826 * This callback is supposed to deal with mc filter in 827 * _rx_ path and has nothing to do with the _tx_ path. 828 * In rx path we always accept everything userspace gives us. 829 */ 830 } 831 832 #define MIN_MTU 68 833 #define MAX_MTU 65535 834 835 static int 836 tun_net_change_mtu(struct net_device *dev, int new_mtu) 837 { 838 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 839 return -EINVAL; 840 dev->mtu = new_mtu; 841 return 0; 842 } 843 844 static netdev_features_t tun_net_fix_features(struct net_device *dev, 845 netdev_features_t features) 846 { 847 struct tun_struct *tun = netdev_priv(dev); 848 849 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 850 } 851 #ifdef CONFIG_NET_POLL_CONTROLLER 852 static void tun_poll_controller(struct net_device *dev) 853 { 854 /* 855 * Tun only receives frames when: 856 * 1) the char device endpoint gets data from user space 857 * 2) the tun socket gets a sendmsg call from user space 858 * Since both of those are synchronous operations, we are guaranteed 859 * never to have pending data when we poll for it 860 * so there is nothing to do here but return. 861 * We need this though so netpoll recognizes us as an interface that 862 * supports polling, which enables bridge devices in virt setups to 863 * still use netconsole 864 */ 865 return; 866 } 867 #endif 868 static const struct net_device_ops tun_netdev_ops = { 869 .ndo_uninit = tun_net_uninit, 870 .ndo_open = tun_net_open, 871 .ndo_stop = tun_net_close, 872 .ndo_start_xmit = tun_net_xmit, 873 .ndo_change_mtu = tun_net_change_mtu, 874 .ndo_fix_features = tun_net_fix_features, 875 .ndo_select_queue = tun_select_queue, 876 #ifdef CONFIG_NET_POLL_CONTROLLER 877 .ndo_poll_controller = tun_poll_controller, 878 #endif 879 }; 880 881 static const struct net_device_ops tap_netdev_ops = { 882 .ndo_uninit = tun_net_uninit, 883 .ndo_open = tun_net_open, 884 .ndo_stop = tun_net_close, 885 .ndo_start_xmit = tun_net_xmit, 886 .ndo_change_mtu = tun_net_change_mtu, 887 .ndo_fix_features = tun_net_fix_features, 888 .ndo_set_rx_mode = tun_net_mclist, 889 .ndo_set_mac_address = eth_mac_addr, 890 .ndo_validate_addr = eth_validate_addr, 891 .ndo_select_queue = tun_select_queue, 892 #ifdef CONFIG_NET_POLL_CONTROLLER 893 .ndo_poll_controller = tun_poll_controller, 894 #endif 895 }; 896 897 static void tun_flow_init(struct tun_struct *tun) 898 { 899 int i; 900 901 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 902 INIT_HLIST_HEAD(&tun->flows[i]); 903 904 tun->ageing_time = TUN_FLOW_EXPIRE; 905 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 906 mod_timer(&tun->flow_gc_timer, 907 round_jiffies_up(jiffies + tun->ageing_time)); 908 } 909 910 static void tun_flow_uninit(struct tun_struct *tun) 911 { 912 del_timer_sync(&tun->flow_gc_timer); 913 tun_flow_flush(tun); 914 } 915 916 /* Initialize net device. */ 917 static void tun_net_init(struct net_device *dev) 918 { 919 struct tun_struct *tun = netdev_priv(dev); 920 921 switch (tun->flags & TUN_TYPE_MASK) { 922 case TUN_TUN_DEV: 923 dev->netdev_ops = &tun_netdev_ops; 924 925 /* Point-to-Point TUN Device */ 926 dev->hard_header_len = 0; 927 dev->addr_len = 0; 928 dev->mtu = 1500; 929 930 /* Zero header length */ 931 dev->type = ARPHRD_NONE; 932 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 933 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 934 break; 935 936 case TUN_TAP_DEV: 937 dev->netdev_ops = &tap_netdev_ops; 938 /* Ethernet TAP Device */ 939 ether_setup(dev); 940 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 941 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 942 943 eth_hw_addr_random(dev); 944 945 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 946 break; 947 } 948 } 949 950 /* Character device part */ 951 952 /* Poll */ 953 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 954 { 955 struct tun_file *tfile = file->private_data; 956 struct tun_struct *tun = __tun_get(tfile); 957 struct sock *sk; 958 unsigned int mask = 0; 959 960 if (!tun) 961 return POLLERR; 962 963 sk = tfile->socket.sk; 964 965 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 966 967 poll_wait(file, sk_sleep(sk), wait); 968 969 if (!skb_queue_empty(&sk->sk_receive_queue)) 970 mask |= POLLIN | POLLRDNORM; 971 972 if (sock_writeable(sk) || 973 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 974 sock_writeable(sk))) 975 mask |= POLLOUT | POLLWRNORM; 976 977 if (tun->dev->reg_state != NETREG_REGISTERED) 978 mask = POLLERR; 979 980 tun_put(tun); 981 return mask; 982 } 983 984 /* prepad is the amount to reserve at front. len is length after that. 985 * linear is a hint as to how much to copy (usually headers). */ 986 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 987 size_t prepad, size_t len, 988 size_t linear, int noblock) 989 { 990 struct sock *sk = tfile->socket.sk; 991 struct sk_buff *skb; 992 int err; 993 994 /* Under a page? Don't bother with paged skb. */ 995 if (prepad + len < PAGE_SIZE || !linear) 996 linear = len; 997 998 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 999 &err, 0); 1000 if (!skb) 1001 return ERR_PTR(err); 1002 1003 skb_reserve(skb, prepad); 1004 skb_put(skb, linear); 1005 skb->data_len = len - linear; 1006 skb->len += len - linear; 1007 1008 return skb; 1009 } 1010 1011 /* Get packet from user space buffer */ 1012 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1013 void *msg_control, const struct iovec *iv, 1014 size_t total_len, size_t count, int noblock) 1015 { 1016 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1017 struct sk_buff *skb; 1018 size_t len = total_len, align = NET_SKB_PAD, linear; 1019 struct virtio_net_hdr gso = { 0 }; 1020 int good_linear; 1021 int offset = 0; 1022 int copylen; 1023 bool zerocopy = false; 1024 int err; 1025 u32 rxhash; 1026 1027 if (!(tun->flags & TUN_NO_PI)) { 1028 if (len < sizeof(pi)) 1029 return -EINVAL; 1030 len -= sizeof(pi); 1031 1032 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) 1033 return -EFAULT; 1034 offset += sizeof(pi); 1035 } 1036 1037 if (tun->flags & TUN_VNET_HDR) { 1038 if (len < tun->vnet_hdr_sz) 1039 return -EINVAL; 1040 len -= tun->vnet_hdr_sz; 1041 1042 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) 1043 return -EFAULT; 1044 1045 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1046 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) 1047 gso.hdr_len = gso.csum_start + gso.csum_offset + 2; 1048 1049 if (gso.hdr_len > len) 1050 return -EINVAL; 1051 offset += tun->vnet_hdr_sz; 1052 } 1053 1054 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { 1055 align += NET_IP_ALIGN; 1056 if (unlikely(len < ETH_HLEN || 1057 (gso.hdr_len && gso.hdr_len < ETH_HLEN))) 1058 return -EINVAL; 1059 } 1060 1061 good_linear = SKB_MAX_HEAD(align); 1062 1063 if (msg_control) { 1064 /* There are 256 bytes to be copied in skb, so there is 1065 * enough room for skb expand head in case it is used. 1066 * The rest of the buffer is mapped from userspace. 1067 */ 1068 copylen = gso.hdr_len ? gso.hdr_len : GOODCOPY_LEN; 1069 if (copylen > good_linear) 1070 copylen = good_linear; 1071 linear = copylen; 1072 if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS) 1073 zerocopy = true; 1074 } 1075 1076 if (!zerocopy) { 1077 copylen = len; 1078 if (gso.hdr_len > good_linear) 1079 linear = good_linear; 1080 else 1081 linear = gso.hdr_len; 1082 } 1083 1084 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1085 if (IS_ERR(skb)) { 1086 if (PTR_ERR(skb) != -EAGAIN) 1087 tun->dev->stats.rx_dropped++; 1088 return PTR_ERR(skb); 1089 } 1090 1091 if (zerocopy) 1092 err = zerocopy_sg_from_iovec(skb, iv, offset, count); 1093 else { 1094 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len); 1095 if (!err && msg_control) { 1096 struct ubuf_info *uarg = msg_control; 1097 uarg->callback(uarg, false); 1098 } 1099 } 1100 1101 if (err) { 1102 tun->dev->stats.rx_dropped++; 1103 kfree_skb(skb); 1104 return -EFAULT; 1105 } 1106 1107 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1108 if (!skb_partial_csum_set(skb, gso.csum_start, 1109 gso.csum_offset)) { 1110 tun->dev->stats.rx_frame_errors++; 1111 kfree_skb(skb); 1112 return -EINVAL; 1113 } 1114 } 1115 1116 switch (tun->flags & TUN_TYPE_MASK) { 1117 case TUN_TUN_DEV: 1118 if (tun->flags & TUN_NO_PI) { 1119 switch (skb->data[0] & 0xf0) { 1120 case 0x40: 1121 pi.proto = htons(ETH_P_IP); 1122 break; 1123 case 0x60: 1124 pi.proto = htons(ETH_P_IPV6); 1125 break; 1126 default: 1127 tun->dev->stats.rx_dropped++; 1128 kfree_skb(skb); 1129 return -EINVAL; 1130 } 1131 } 1132 1133 skb_reset_mac_header(skb); 1134 skb->protocol = pi.proto; 1135 skb->dev = tun->dev; 1136 break; 1137 case TUN_TAP_DEV: 1138 skb->protocol = eth_type_trans(skb, tun->dev); 1139 break; 1140 } 1141 1142 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1143 pr_debug("GSO!\n"); 1144 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1145 case VIRTIO_NET_HDR_GSO_TCPV4: 1146 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1147 break; 1148 case VIRTIO_NET_HDR_GSO_TCPV6: 1149 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1150 break; 1151 case VIRTIO_NET_HDR_GSO_UDP: 1152 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1153 break; 1154 default: 1155 tun->dev->stats.rx_frame_errors++; 1156 kfree_skb(skb); 1157 return -EINVAL; 1158 } 1159 1160 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1161 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1162 1163 skb_shinfo(skb)->gso_size = gso.gso_size; 1164 if (skb_shinfo(skb)->gso_size == 0) { 1165 tun->dev->stats.rx_frame_errors++; 1166 kfree_skb(skb); 1167 return -EINVAL; 1168 } 1169 1170 /* Header must be checked, and gso_segs computed. */ 1171 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1172 skb_shinfo(skb)->gso_segs = 0; 1173 } 1174 1175 /* copy skb_ubuf_info for callback when skb has no error */ 1176 if (zerocopy) { 1177 skb_shinfo(skb)->destructor_arg = msg_control; 1178 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1179 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1180 } 1181 1182 skb_reset_network_header(skb); 1183 skb_probe_transport_header(skb, 0); 1184 1185 rxhash = skb_get_hash(skb); 1186 netif_rx_ni(skb); 1187 1188 tun->dev->stats.rx_packets++; 1189 tun->dev->stats.rx_bytes += len; 1190 1191 tun_flow_update(tun, rxhash, tfile); 1192 return total_len; 1193 } 1194 1195 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 1196 unsigned long count, loff_t pos) 1197 { 1198 struct file *file = iocb->ki_filp; 1199 struct tun_struct *tun = tun_get(file); 1200 struct tun_file *tfile = file->private_data; 1201 ssize_t result; 1202 1203 if (!tun) 1204 return -EBADFD; 1205 1206 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count); 1207 1208 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count), 1209 count, file->f_flags & O_NONBLOCK); 1210 1211 tun_put(tun); 1212 return result; 1213 } 1214 1215 /* Put packet to the user space buffer */ 1216 static ssize_t tun_put_user(struct tun_struct *tun, 1217 struct tun_file *tfile, 1218 struct sk_buff *skb, 1219 const struct iovec *iv, int len) 1220 { 1221 struct tun_pi pi = { 0, skb->protocol }; 1222 ssize_t total = 0; 1223 int vlan_offset = 0, copied; 1224 1225 if (!(tun->flags & TUN_NO_PI)) { 1226 if ((len -= sizeof(pi)) < 0) 1227 return -EINVAL; 1228 1229 if (len < skb->len) { 1230 /* Packet will be striped */ 1231 pi.flags |= TUN_PKT_STRIP; 1232 } 1233 1234 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi))) 1235 return -EFAULT; 1236 total += sizeof(pi); 1237 } 1238 1239 if (tun->flags & TUN_VNET_HDR) { 1240 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1241 if ((len -= tun->vnet_hdr_sz) < 0) 1242 return -EINVAL; 1243 1244 if (skb_is_gso(skb)) { 1245 struct skb_shared_info *sinfo = skb_shinfo(skb); 1246 1247 /* This is a hint as to how much should be linear. */ 1248 gso.hdr_len = skb_headlen(skb); 1249 gso.gso_size = sinfo->gso_size; 1250 if (sinfo->gso_type & SKB_GSO_TCPV4) 1251 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1252 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1253 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1254 else if (sinfo->gso_type & SKB_GSO_UDP) 1255 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1256 else { 1257 pr_err("unexpected GSO type: " 1258 "0x%x, gso_size %d, hdr_len %d\n", 1259 sinfo->gso_type, gso.gso_size, 1260 gso.hdr_len); 1261 print_hex_dump(KERN_ERR, "tun: ", 1262 DUMP_PREFIX_NONE, 1263 16, 1, skb->head, 1264 min((int)gso.hdr_len, 64), true); 1265 WARN_ON_ONCE(1); 1266 return -EINVAL; 1267 } 1268 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1269 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1270 } else 1271 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1272 1273 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1274 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1275 gso.csum_start = skb_checksum_start_offset(skb); 1276 gso.csum_offset = skb->csum_offset; 1277 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1278 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1279 } /* else everything is zero */ 1280 1281 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, 1282 sizeof(gso)))) 1283 return -EFAULT; 1284 total += tun->vnet_hdr_sz; 1285 } 1286 1287 copied = total; 1288 total += skb->len; 1289 if (!vlan_tx_tag_present(skb)) { 1290 len = min_t(int, skb->len, len); 1291 } else { 1292 int copy, ret; 1293 struct { 1294 __be16 h_vlan_proto; 1295 __be16 h_vlan_TCI; 1296 } veth; 1297 1298 veth.h_vlan_proto = skb->vlan_proto; 1299 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 1300 1301 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1302 len = min_t(int, skb->len + VLAN_HLEN, len); 1303 total += VLAN_HLEN; 1304 1305 copy = min_t(int, vlan_offset, len); 1306 ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); 1307 len -= copy; 1308 copied += copy; 1309 if (ret || !len) 1310 goto done; 1311 1312 copy = min_t(int, sizeof(veth), len); 1313 ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy); 1314 len -= copy; 1315 copied += copy; 1316 if (ret || !len) 1317 goto done; 1318 } 1319 1320 skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len); 1321 1322 done: 1323 tun->dev->stats.tx_packets++; 1324 tun->dev->stats.tx_bytes += len; 1325 1326 return total; 1327 } 1328 1329 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1330 const struct iovec *iv, ssize_t len, int noblock) 1331 { 1332 struct sk_buff *skb; 1333 ssize_t ret = 0; 1334 int peeked, err, off = 0; 1335 1336 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1337 1338 if (!len) 1339 return ret; 1340 1341 if (tun->dev->reg_state != NETREG_REGISTERED) 1342 return -EIO; 1343 1344 /* Read frames from queue */ 1345 skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0, 1346 &peeked, &off, &err); 1347 if (skb) { 1348 ret = tun_put_user(tun, tfile, skb, iv, len); 1349 kfree_skb(skb); 1350 } else 1351 ret = err; 1352 1353 return ret; 1354 } 1355 1356 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 1357 unsigned long count, loff_t pos) 1358 { 1359 struct file *file = iocb->ki_filp; 1360 struct tun_file *tfile = file->private_data; 1361 struct tun_struct *tun = __tun_get(tfile); 1362 ssize_t len, ret; 1363 1364 if (!tun) 1365 return -EBADFD; 1366 len = iov_length(iv, count); 1367 if (len < 0) { 1368 ret = -EINVAL; 1369 goto out; 1370 } 1371 1372 ret = tun_do_read(tun, tfile, iv, len, 1373 file->f_flags & O_NONBLOCK); 1374 ret = min_t(ssize_t, ret, len); 1375 if (ret > 0) 1376 iocb->ki_pos = ret; 1377 out: 1378 tun_put(tun); 1379 return ret; 1380 } 1381 1382 static void tun_free_netdev(struct net_device *dev) 1383 { 1384 struct tun_struct *tun = netdev_priv(dev); 1385 1386 BUG_ON(!(list_empty(&tun->disabled))); 1387 tun_flow_uninit(tun); 1388 security_tun_dev_free_security(tun->security); 1389 free_netdev(dev); 1390 } 1391 1392 static void tun_setup(struct net_device *dev) 1393 { 1394 struct tun_struct *tun = netdev_priv(dev); 1395 1396 tun->owner = INVALID_UID; 1397 tun->group = INVALID_GID; 1398 1399 dev->ethtool_ops = &tun_ethtool_ops; 1400 dev->destructor = tun_free_netdev; 1401 } 1402 1403 /* Trivial set of netlink ops to allow deleting tun or tap 1404 * device with netlink. 1405 */ 1406 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1407 { 1408 return -EINVAL; 1409 } 1410 1411 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1412 .kind = DRV_NAME, 1413 .priv_size = sizeof(struct tun_struct), 1414 .setup = tun_setup, 1415 .validate = tun_validate, 1416 }; 1417 1418 static void tun_sock_write_space(struct sock *sk) 1419 { 1420 struct tun_file *tfile; 1421 wait_queue_head_t *wqueue; 1422 1423 if (!sock_writeable(sk)) 1424 return; 1425 1426 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1427 return; 1428 1429 wqueue = sk_sleep(sk); 1430 if (wqueue && waitqueue_active(wqueue)) 1431 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1432 POLLWRNORM | POLLWRBAND); 1433 1434 tfile = container_of(sk, struct tun_file, sk); 1435 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1436 } 1437 1438 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1439 struct msghdr *m, size_t total_len) 1440 { 1441 int ret; 1442 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1443 struct tun_struct *tun = __tun_get(tfile); 1444 1445 if (!tun) 1446 return -EBADFD; 1447 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len, 1448 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); 1449 tun_put(tun); 1450 return ret; 1451 } 1452 1453 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1454 struct msghdr *m, size_t total_len, 1455 int flags) 1456 { 1457 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1458 struct tun_struct *tun = __tun_get(tfile); 1459 int ret; 1460 1461 if (!tun) 1462 return -EBADFD; 1463 1464 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1465 ret = -EINVAL; 1466 goto out; 1467 } 1468 if (flags & MSG_ERRQUEUE) { 1469 ret = sock_recv_errqueue(sock->sk, m, total_len, 1470 SOL_PACKET, TUN_TX_TIMESTAMP); 1471 goto out; 1472 } 1473 ret = tun_do_read(tun, tfile, m->msg_iov, total_len, 1474 flags & MSG_DONTWAIT); 1475 if (ret > total_len) { 1476 m->msg_flags |= MSG_TRUNC; 1477 ret = flags & MSG_TRUNC ? ret : total_len; 1478 } 1479 out: 1480 tun_put(tun); 1481 return ret; 1482 } 1483 1484 static int tun_release(struct socket *sock) 1485 { 1486 if (sock->sk) 1487 sock_put(sock->sk); 1488 return 0; 1489 } 1490 1491 /* Ops structure to mimic raw sockets with tun */ 1492 static const struct proto_ops tun_socket_ops = { 1493 .sendmsg = tun_sendmsg, 1494 .recvmsg = tun_recvmsg, 1495 .release = tun_release, 1496 }; 1497 1498 static struct proto tun_proto = { 1499 .name = "tun", 1500 .owner = THIS_MODULE, 1501 .obj_size = sizeof(struct tun_file), 1502 }; 1503 1504 static int tun_flags(struct tun_struct *tun) 1505 { 1506 int flags = 0; 1507 1508 if (tun->flags & TUN_TUN_DEV) 1509 flags |= IFF_TUN; 1510 else 1511 flags |= IFF_TAP; 1512 1513 if (tun->flags & TUN_NO_PI) 1514 flags |= IFF_NO_PI; 1515 1516 /* This flag has no real effect. We track the value for backwards 1517 * compatibility. 1518 */ 1519 if (tun->flags & TUN_ONE_QUEUE) 1520 flags |= IFF_ONE_QUEUE; 1521 1522 if (tun->flags & TUN_VNET_HDR) 1523 flags |= IFF_VNET_HDR; 1524 1525 if (tun->flags & TUN_TAP_MQ) 1526 flags |= IFF_MULTI_QUEUE; 1527 1528 if (tun->flags & TUN_PERSIST) 1529 flags |= IFF_PERSIST; 1530 1531 return flags; 1532 } 1533 1534 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1535 char *buf) 1536 { 1537 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1538 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1539 } 1540 1541 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1542 char *buf) 1543 { 1544 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1545 return uid_valid(tun->owner)? 1546 sprintf(buf, "%u\n", 1547 from_kuid_munged(current_user_ns(), tun->owner)): 1548 sprintf(buf, "-1\n"); 1549 } 1550 1551 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1552 char *buf) 1553 { 1554 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1555 return gid_valid(tun->group) ? 1556 sprintf(buf, "%u\n", 1557 from_kgid_munged(current_user_ns(), tun->group)): 1558 sprintf(buf, "-1\n"); 1559 } 1560 1561 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1562 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1563 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1564 1565 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1566 { 1567 struct tun_struct *tun; 1568 struct tun_file *tfile = file->private_data; 1569 struct net_device *dev; 1570 int err; 1571 1572 if (tfile->detached) 1573 return -EINVAL; 1574 1575 dev = __dev_get_by_name(net, ifr->ifr_name); 1576 if (dev) { 1577 if (ifr->ifr_flags & IFF_TUN_EXCL) 1578 return -EBUSY; 1579 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1580 tun = netdev_priv(dev); 1581 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1582 tun = netdev_priv(dev); 1583 else 1584 return -EINVAL; 1585 1586 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1587 !!(tun->flags & TUN_TAP_MQ)) 1588 return -EINVAL; 1589 1590 if (tun_not_capable(tun)) 1591 return -EPERM; 1592 err = security_tun_dev_open(tun->security); 1593 if (err < 0) 1594 return err; 1595 1596 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1597 if (err < 0) 1598 return err; 1599 1600 if (tun->flags & TUN_TAP_MQ && 1601 (tun->numqueues + tun->numdisabled > 1)) { 1602 /* One or more queue has already been attached, no need 1603 * to initialize the device again. 1604 */ 1605 return 0; 1606 } 1607 } 1608 else { 1609 char *name; 1610 unsigned long flags = 0; 1611 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1612 MAX_TAP_QUEUES : 1; 1613 1614 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1615 return -EPERM; 1616 err = security_tun_dev_create(); 1617 if (err < 0) 1618 return err; 1619 1620 /* Set dev type */ 1621 if (ifr->ifr_flags & IFF_TUN) { 1622 /* TUN device */ 1623 flags |= TUN_TUN_DEV; 1624 name = "tun%d"; 1625 } else if (ifr->ifr_flags & IFF_TAP) { 1626 /* TAP device */ 1627 flags |= TUN_TAP_DEV; 1628 name = "tap%d"; 1629 } else 1630 return -EINVAL; 1631 1632 if (*ifr->ifr_name) 1633 name = ifr->ifr_name; 1634 1635 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1636 NET_NAME_UNKNOWN, tun_setup, queues, 1637 queues); 1638 1639 if (!dev) 1640 return -ENOMEM; 1641 1642 dev_net_set(dev, net); 1643 dev->rtnl_link_ops = &tun_link_ops; 1644 dev->ifindex = tfile->ifindex; 1645 1646 tun = netdev_priv(dev); 1647 tun->dev = dev; 1648 tun->flags = flags; 1649 tun->txflt.count = 0; 1650 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1651 1652 tun->filter_attached = false; 1653 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1654 1655 spin_lock_init(&tun->lock); 1656 1657 err = security_tun_dev_alloc_security(&tun->security); 1658 if (err < 0) 1659 goto err_free_dev; 1660 1661 tun_net_init(dev); 1662 tun_flow_init(tun); 1663 1664 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1665 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1666 NETIF_F_HW_VLAN_STAG_TX; 1667 dev->features = dev->hw_features; 1668 dev->vlan_features = dev->features & 1669 ~(NETIF_F_HW_VLAN_CTAG_TX | 1670 NETIF_F_HW_VLAN_STAG_TX); 1671 1672 INIT_LIST_HEAD(&tun->disabled); 1673 err = tun_attach(tun, file, false); 1674 if (err < 0) 1675 goto err_free_flow; 1676 1677 err = register_netdevice(tun->dev); 1678 if (err < 0) 1679 goto err_detach; 1680 1681 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1682 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1683 device_create_file(&tun->dev->dev, &dev_attr_group)) 1684 pr_err("Failed to create tun sysfs files\n"); 1685 } 1686 1687 netif_carrier_on(tun->dev); 1688 1689 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1690 1691 if (ifr->ifr_flags & IFF_NO_PI) 1692 tun->flags |= TUN_NO_PI; 1693 else 1694 tun->flags &= ~TUN_NO_PI; 1695 1696 /* This flag has no real effect. We track the value for backwards 1697 * compatibility. 1698 */ 1699 if (ifr->ifr_flags & IFF_ONE_QUEUE) 1700 tun->flags |= TUN_ONE_QUEUE; 1701 else 1702 tun->flags &= ~TUN_ONE_QUEUE; 1703 1704 if (ifr->ifr_flags & IFF_VNET_HDR) 1705 tun->flags |= TUN_VNET_HDR; 1706 else 1707 tun->flags &= ~TUN_VNET_HDR; 1708 1709 if (ifr->ifr_flags & IFF_MULTI_QUEUE) 1710 tun->flags |= TUN_TAP_MQ; 1711 else 1712 tun->flags &= ~TUN_TAP_MQ; 1713 1714 /* Make sure persistent devices do not get stuck in 1715 * xoff state. 1716 */ 1717 if (netif_running(tun->dev)) 1718 netif_tx_wake_all_queues(tun->dev); 1719 1720 strcpy(ifr->ifr_name, tun->dev->name); 1721 return 0; 1722 1723 err_detach: 1724 tun_detach_all(dev); 1725 err_free_flow: 1726 tun_flow_uninit(tun); 1727 security_tun_dev_free_security(tun->security); 1728 err_free_dev: 1729 free_netdev(dev); 1730 return err; 1731 } 1732 1733 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1734 struct ifreq *ifr) 1735 { 1736 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1737 1738 strcpy(ifr->ifr_name, tun->dev->name); 1739 1740 ifr->ifr_flags = tun_flags(tun); 1741 1742 } 1743 1744 /* This is like a cut-down ethtool ops, except done via tun fd so no 1745 * privs required. */ 1746 static int set_offload(struct tun_struct *tun, unsigned long arg) 1747 { 1748 netdev_features_t features = 0; 1749 1750 if (arg & TUN_F_CSUM) { 1751 features |= NETIF_F_HW_CSUM; 1752 arg &= ~TUN_F_CSUM; 1753 1754 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1755 if (arg & TUN_F_TSO_ECN) { 1756 features |= NETIF_F_TSO_ECN; 1757 arg &= ~TUN_F_TSO_ECN; 1758 } 1759 if (arg & TUN_F_TSO4) 1760 features |= NETIF_F_TSO; 1761 if (arg & TUN_F_TSO6) 1762 features |= NETIF_F_TSO6; 1763 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1764 } 1765 1766 if (arg & TUN_F_UFO) { 1767 features |= NETIF_F_UFO; 1768 arg &= ~TUN_F_UFO; 1769 } 1770 } 1771 1772 /* This gives the user a way to test for new features in future by 1773 * trying to set them. */ 1774 if (arg) 1775 return -EINVAL; 1776 1777 tun->set_features = features; 1778 netdev_update_features(tun->dev); 1779 1780 return 0; 1781 } 1782 1783 static void tun_detach_filter(struct tun_struct *tun, int n) 1784 { 1785 int i; 1786 struct tun_file *tfile; 1787 1788 for (i = 0; i < n; i++) { 1789 tfile = rtnl_dereference(tun->tfiles[i]); 1790 sk_detach_filter(tfile->socket.sk); 1791 } 1792 1793 tun->filter_attached = false; 1794 } 1795 1796 static int tun_attach_filter(struct tun_struct *tun) 1797 { 1798 int i, ret = 0; 1799 struct tun_file *tfile; 1800 1801 for (i = 0; i < tun->numqueues; i++) { 1802 tfile = rtnl_dereference(tun->tfiles[i]); 1803 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1804 if (ret) { 1805 tun_detach_filter(tun, i); 1806 return ret; 1807 } 1808 } 1809 1810 tun->filter_attached = true; 1811 return ret; 1812 } 1813 1814 static void tun_set_sndbuf(struct tun_struct *tun) 1815 { 1816 struct tun_file *tfile; 1817 int i; 1818 1819 for (i = 0; i < tun->numqueues; i++) { 1820 tfile = rtnl_dereference(tun->tfiles[i]); 1821 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1822 } 1823 } 1824 1825 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1826 { 1827 struct tun_file *tfile = file->private_data; 1828 struct tun_struct *tun; 1829 int ret = 0; 1830 1831 rtnl_lock(); 1832 1833 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1834 tun = tfile->detached; 1835 if (!tun) { 1836 ret = -EINVAL; 1837 goto unlock; 1838 } 1839 ret = security_tun_dev_attach_queue(tun->security); 1840 if (ret < 0) 1841 goto unlock; 1842 ret = tun_attach(tun, file, false); 1843 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1844 tun = rtnl_dereference(tfile->tun); 1845 if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) 1846 ret = -EINVAL; 1847 else 1848 __tun_detach(tfile, false); 1849 } else 1850 ret = -EINVAL; 1851 1852 unlock: 1853 rtnl_unlock(); 1854 return ret; 1855 } 1856 1857 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1858 unsigned long arg, int ifreq_len) 1859 { 1860 struct tun_file *tfile = file->private_data; 1861 struct tun_struct *tun; 1862 void __user* argp = (void __user*)arg; 1863 struct ifreq ifr; 1864 kuid_t owner; 1865 kgid_t group; 1866 int sndbuf; 1867 int vnet_hdr_sz; 1868 unsigned int ifindex; 1869 int ret; 1870 1871 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1872 if (copy_from_user(&ifr, argp, ifreq_len)) 1873 return -EFAULT; 1874 } else { 1875 memset(&ifr, 0, sizeof(ifr)); 1876 } 1877 if (cmd == TUNGETFEATURES) { 1878 /* Currently this just means: "what IFF flags are valid?". 1879 * This is needed because we never checked for invalid flags on 1880 * TUNSETIFF. */ 1881 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | 1882 IFF_VNET_HDR | IFF_MULTI_QUEUE, 1883 (unsigned int __user*)argp); 1884 } else if (cmd == TUNSETQUEUE) 1885 return tun_set_queue(file, &ifr); 1886 1887 ret = 0; 1888 rtnl_lock(); 1889 1890 tun = __tun_get(tfile); 1891 if (cmd == TUNSETIFF && !tun) { 1892 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1893 1894 ret = tun_set_iff(tfile->net, file, &ifr); 1895 1896 if (ret) 1897 goto unlock; 1898 1899 if (copy_to_user(argp, &ifr, ifreq_len)) 1900 ret = -EFAULT; 1901 goto unlock; 1902 } 1903 if (cmd == TUNSETIFINDEX) { 1904 ret = -EPERM; 1905 if (tun) 1906 goto unlock; 1907 1908 ret = -EFAULT; 1909 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1910 goto unlock; 1911 1912 ret = 0; 1913 tfile->ifindex = ifindex; 1914 goto unlock; 1915 } 1916 1917 ret = -EBADFD; 1918 if (!tun) 1919 goto unlock; 1920 1921 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1922 1923 ret = 0; 1924 switch (cmd) { 1925 case TUNGETIFF: 1926 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1927 1928 if (tfile->detached) 1929 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1930 if (!tfile->socket.sk->sk_filter) 1931 ifr.ifr_flags |= IFF_NOFILTER; 1932 1933 if (copy_to_user(argp, &ifr, ifreq_len)) 1934 ret = -EFAULT; 1935 break; 1936 1937 case TUNSETNOCSUM: 1938 /* Disable/Enable checksum */ 1939 1940 /* [unimplemented] */ 1941 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1942 arg ? "disabled" : "enabled"); 1943 break; 1944 1945 case TUNSETPERSIST: 1946 /* Disable/Enable persist mode. Keep an extra reference to the 1947 * module to prevent the module being unprobed. 1948 */ 1949 if (arg && !(tun->flags & TUN_PERSIST)) { 1950 tun->flags |= TUN_PERSIST; 1951 __module_get(THIS_MODULE); 1952 } 1953 if (!arg && (tun->flags & TUN_PERSIST)) { 1954 tun->flags &= ~TUN_PERSIST; 1955 module_put(THIS_MODULE); 1956 } 1957 1958 tun_debug(KERN_INFO, tun, "persist %s\n", 1959 arg ? "enabled" : "disabled"); 1960 break; 1961 1962 case TUNSETOWNER: 1963 /* Set owner of the device */ 1964 owner = make_kuid(current_user_ns(), arg); 1965 if (!uid_valid(owner)) { 1966 ret = -EINVAL; 1967 break; 1968 } 1969 tun->owner = owner; 1970 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1971 from_kuid(&init_user_ns, tun->owner)); 1972 break; 1973 1974 case TUNSETGROUP: 1975 /* Set group of the device */ 1976 group = make_kgid(current_user_ns(), arg); 1977 if (!gid_valid(group)) { 1978 ret = -EINVAL; 1979 break; 1980 } 1981 tun->group = group; 1982 tun_debug(KERN_INFO, tun, "group set to %u\n", 1983 from_kgid(&init_user_ns, tun->group)); 1984 break; 1985 1986 case TUNSETLINK: 1987 /* Only allow setting the type when the interface is down */ 1988 if (tun->dev->flags & IFF_UP) { 1989 tun_debug(KERN_INFO, tun, 1990 "Linktype set failed because interface is up\n"); 1991 ret = -EBUSY; 1992 } else { 1993 tun->dev->type = (int) arg; 1994 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1995 tun->dev->type); 1996 ret = 0; 1997 } 1998 break; 1999 2000 #ifdef TUN_DEBUG 2001 case TUNSETDEBUG: 2002 tun->debug = arg; 2003 break; 2004 #endif 2005 case TUNSETOFFLOAD: 2006 ret = set_offload(tun, arg); 2007 break; 2008 2009 case TUNSETTXFILTER: 2010 /* Can be set only for TAPs */ 2011 ret = -EINVAL; 2012 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2013 break; 2014 ret = update_filter(&tun->txflt, (void __user *)arg); 2015 break; 2016 2017 case SIOCGIFHWADDR: 2018 /* Get hw address */ 2019 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 2020 ifr.ifr_hwaddr.sa_family = tun->dev->type; 2021 if (copy_to_user(argp, &ifr, ifreq_len)) 2022 ret = -EFAULT; 2023 break; 2024 2025 case SIOCSIFHWADDR: 2026 /* Set hw address */ 2027 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 2028 ifr.ifr_hwaddr.sa_data); 2029 2030 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2031 break; 2032 2033 case TUNGETSNDBUF: 2034 sndbuf = tfile->socket.sk->sk_sndbuf; 2035 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2036 ret = -EFAULT; 2037 break; 2038 2039 case TUNSETSNDBUF: 2040 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2041 ret = -EFAULT; 2042 break; 2043 } 2044 2045 tun->sndbuf = sndbuf; 2046 tun_set_sndbuf(tun); 2047 break; 2048 2049 case TUNGETVNETHDRSZ: 2050 vnet_hdr_sz = tun->vnet_hdr_sz; 2051 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2052 ret = -EFAULT; 2053 break; 2054 2055 case TUNSETVNETHDRSZ: 2056 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2057 ret = -EFAULT; 2058 break; 2059 } 2060 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2061 ret = -EINVAL; 2062 break; 2063 } 2064 2065 tun->vnet_hdr_sz = vnet_hdr_sz; 2066 break; 2067 2068 case TUNATTACHFILTER: 2069 /* Can be set only for TAPs */ 2070 ret = -EINVAL; 2071 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2072 break; 2073 ret = -EFAULT; 2074 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2075 break; 2076 2077 ret = tun_attach_filter(tun); 2078 break; 2079 2080 case TUNDETACHFILTER: 2081 /* Can be set only for TAPs */ 2082 ret = -EINVAL; 2083 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2084 break; 2085 ret = 0; 2086 tun_detach_filter(tun, tun->numqueues); 2087 break; 2088 2089 case TUNGETFILTER: 2090 ret = -EINVAL; 2091 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2092 break; 2093 ret = -EFAULT; 2094 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2095 break; 2096 ret = 0; 2097 break; 2098 2099 default: 2100 ret = -EINVAL; 2101 break; 2102 } 2103 2104 unlock: 2105 rtnl_unlock(); 2106 if (tun) 2107 tun_put(tun); 2108 return ret; 2109 } 2110 2111 static long tun_chr_ioctl(struct file *file, 2112 unsigned int cmd, unsigned long arg) 2113 { 2114 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2115 } 2116 2117 #ifdef CONFIG_COMPAT 2118 static long tun_chr_compat_ioctl(struct file *file, 2119 unsigned int cmd, unsigned long arg) 2120 { 2121 switch (cmd) { 2122 case TUNSETIFF: 2123 case TUNGETIFF: 2124 case TUNSETTXFILTER: 2125 case TUNGETSNDBUF: 2126 case TUNSETSNDBUF: 2127 case SIOCGIFHWADDR: 2128 case SIOCSIFHWADDR: 2129 arg = (unsigned long)compat_ptr(arg); 2130 break; 2131 default: 2132 arg = (compat_ulong_t)arg; 2133 break; 2134 } 2135 2136 /* 2137 * compat_ifreq is shorter than ifreq, so we must not access beyond 2138 * the end of that structure. All fields that are used in this 2139 * driver are compatible though, we don't need to convert the 2140 * contents. 2141 */ 2142 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2143 } 2144 #endif /* CONFIG_COMPAT */ 2145 2146 static int tun_chr_fasync(int fd, struct file *file, int on) 2147 { 2148 struct tun_file *tfile = file->private_data; 2149 int ret; 2150 2151 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2152 goto out; 2153 2154 if (on) { 2155 __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2156 tfile->flags |= TUN_FASYNC; 2157 } else 2158 tfile->flags &= ~TUN_FASYNC; 2159 ret = 0; 2160 out: 2161 return ret; 2162 } 2163 2164 static int tun_chr_open(struct inode *inode, struct file * file) 2165 { 2166 struct tun_file *tfile; 2167 2168 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2169 2170 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2171 &tun_proto); 2172 if (!tfile) 2173 return -ENOMEM; 2174 RCU_INIT_POINTER(tfile->tun, NULL); 2175 tfile->net = get_net(current->nsproxy->net_ns); 2176 tfile->flags = 0; 2177 tfile->ifindex = 0; 2178 2179 init_waitqueue_head(&tfile->wq.wait); 2180 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq); 2181 2182 tfile->socket.file = file; 2183 tfile->socket.ops = &tun_socket_ops; 2184 2185 sock_init_data(&tfile->socket, &tfile->sk); 2186 sk_change_net(&tfile->sk, tfile->net); 2187 2188 tfile->sk.sk_write_space = tun_sock_write_space; 2189 tfile->sk.sk_sndbuf = INT_MAX; 2190 2191 file->private_data = tfile; 2192 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2193 INIT_LIST_HEAD(&tfile->next); 2194 2195 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2196 2197 return 0; 2198 } 2199 2200 static int tun_chr_close(struct inode *inode, struct file *file) 2201 { 2202 struct tun_file *tfile = file->private_data; 2203 struct net *net = tfile->net; 2204 2205 tun_detach(tfile, true); 2206 put_net(net); 2207 2208 return 0; 2209 } 2210 2211 #ifdef CONFIG_PROC_FS 2212 static int tun_chr_show_fdinfo(struct seq_file *m, struct file *f) 2213 { 2214 struct tun_struct *tun; 2215 struct ifreq ifr; 2216 2217 memset(&ifr, 0, sizeof(ifr)); 2218 2219 rtnl_lock(); 2220 tun = tun_get(f); 2221 if (tun) 2222 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 2223 rtnl_unlock(); 2224 2225 if (tun) 2226 tun_put(tun); 2227 2228 return seq_printf(m, "iff:\t%s\n", ifr.ifr_name); 2229 } 2230 #endif 2231 2232 static const struct file_operations tun_fops = { 2233 .owner = THIS_MODULE, 2234 .llseek = no_llseek, 2235 .read = do_sync_read, 2236 .aio_read = tun_chr_aio_read, 2237 .write = do_sync_write, 2238 .aio_write = tun_chr_aio_write, 2239 .poll = tun_chr_poll, 2240 .unlocked_ioctl = tun_chr_ioctl, 2241 #ifdef CONFIG_COMPAT 2242 .compat_ioctl = tun_chr_compat_ioctl, 2243 #endif 2244 .open = tun_chr_open, 2245 .release = tun_chr_close, 2246 .fasync = tun_chr_fasync, 2247 #ifdef CONFIG_PROC_FS 2248 .show_fdinfo = tun_chr_show_fdinfo, 2249 #endif 2250 }; 2251 2252 static struct miscdevice tun_miscdev = { 2253 .minor = TUN_MINOR, 2254 .name = "tun", 2255 .nodename = "net/tun", 2256 .fops = &tun_fops, 2257 }; 2258 2259 /* ethtool interface */ 2260 2261 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2262 { 2263 cmd->supported = 0; 2264 cmd->advertising = 0; 2265 ethtool_cmd_speed_set(cmd, SPEED_10); 2266 cmd->duplex = DUPLEX_FULL; 2267 cmd->port = PORT_TP; 2268 cmd->phy_address = 0; 2269 cmd->transceiver = XCVR_INTERNAL; 2270 cmd->autoneg = AUTONEG_DISABLE; 2271 cmd->maxtxpkt = 0; 2272 cmd->maxrxpkt = 0; 2273 return 0; 2274 } 2275 2276 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2277 { 2278 struct tun_struct *tun = netdev_priv(dev); 2279 2280 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2281 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2282 2283 switch (tun->flags & TUN_TYPE_MASK) { 2284 case TUN_TUN_DEV: 2285 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2286 break; 2287 case TUN_TAP_DEV: 2288 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2289 break; 2290 } 2291 } 2292 2293 static u32 tun_get_msglevel(struct net_device *dev) 2294 { 2295 #ifdef TUN_DEBUG 2296 struct tun_struct *tun = netdev_priv(dev); 2297 return tun->debug; 2298 #else 2299 return -EOPNOTSUPP; 2300 #endif 2301 } 2302 2303 static void tun_set_msglevel(struct net_device *dev, u32 value) 2304 { 2305 #ifdef TUN_DEBUG 2306 struct tun_struct *tun = netdev_priv(dev); 2307 tun->debug = value; 2308 #endif 2309 } 2310 2311 static const struct ethtool_ops tun_ethtool_ops = { 2312 .get_settings = tun_get_settings, 2313 .get_drvinfo = tun_get_drvinfo, 2314 .get_msglevel = tun_get_msglevel, 2315 .set_msglevel = tun_set_msglevel, 2316 .get_link = ethtool_op_get_link, 2317 .get_ts_info = ethtool_op_get_ts_info, 2318 }; 2319 2320 2321 static int __init tun_init(void) 2322 { 2323 int ret = 0; 2324 2325 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2326 pr_info("%s\n", DRV_COPYRIGHT); 2327 2328 ret = rtnl_link_register(&tun_link_ops); 2329 if (ret) { 2330 pr_err("Can't register link_ops\n"); 2331 goto err_linkops; 2332 } 2333 2334 ret = misc_register(&tun_miscdev); 2335 if (ret) { 2336 pr_err("Can't register misc device %d\n", TUN_MINOR); 2337 goto err_misc; 2338 } 2339 return 0; 2340 err_misc: 2341 rtnl_link_unregister(&tun_link_ops); 2342 err_linkops: 2343 return ret; 2344 } 2345 2346 static void tun_cleanup(void) 2347 { 2348 misc_deregister(&tun_miscdev); 2349 rtnl_link_unregister(&tun_link_ops); 2350 } 2351 2352 /* Get an underlying socket object from tun file. Returns error unless file is 2353 * attached to a device. The returned object works like a packet socket, it 2354 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2355 * holding a reference to the file for as long as the socket is in use. */ 2356 struct socket *tun_get_socket(struct file *file) 2357 { 2358 struct tun_file *tfile; 2359 if (file->f_op != &tun_fops) 2360 return ERR_PTR(-EINVAL); 2361 tfile = file->private_data; 2362 if (!tfile) 2363 return ERR_PTR(-EBADFD); 2364 return &tfile->socket; 2365 } 2366 EXPORT_SYMBOL_GPL(tun_get_socket); 2367 2368 module_init(tun_init); 2369 module_exit(tun_cleanup); 2370 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2371 MODULE_AUTHOR(DRV_COPYRIGHT); 2372 MODULE_LICENSE("GPL"); 2373 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2374 MODULE_ALIAS("devname:net/tun"); 2375