1 /* 2 * TUN - Universal TUN/TAP device driver. 3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $ 16 */ 17 18 /* 19 * Changes: 20 * 21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14 22 * Add TUNSETLINK ioctl to set the link encapsulation 23 * 24 * Mark Smith <markzzzsmith@yahoo.com.au> 25 * Use eth_random_addr() for tap MAC address. 26 * 27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20 28 * Fixes in packet dropping, queue length setting and queue wakeup. 29 * Increased default tx queue length. 30 * Added ethtool API. 31 * Minor cleanups 32 * 33 * Daniel Podlejski <underley@underley.eu.org> 34 * Modifications for 2.3.99-pre5 kernel. 35 */ 36 37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 38 39 #define DRV_NAME "tun" 40 #define DRV_VERSION "1.6" 41 #define DRV_DESCRIPTION "Universal TUN/TAP device driver" 42 #define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>" 43 44 #include <linux/module.h> 45 #include <linux/errno.h> 46 #include <linux/kernel.h> 47 #include <linux/major.h> 48 #include <linux/slab.h> 49 #include <linux/poll.h> 50 #include <linux/fcntl.h> 51 #include <linux/init.h> 52 #include <linux/skbuff.h> 53 #include <linux/netdevice.h> 54 #include <linux/etherdevice.h> 55 #include <linux/miscdevice.h> 56 #include <linux/ethtool.h> 57 #include <linux/rtnetlink.h> 58 #include <linux/compat.h> 59 #include <linux/if.h> 60 #include <linux/if_arp.h> 61 #include <linux/if_ether.h> 62 #include <linux/if_tun.h> 63 #include <linux/if_vlan.h> 64 #include <linux/crc32.h> 65 #include <linux/nsproxy.h> 66 #include <linux/virtio_net.h> 67 #include <linux/rcupdate.h> 68 #include <net/ipv6.h> 69 #include <net/net_namespace.h> 70 #include <net/netns/generic.h> 71 #include <net/rtnetlink.h> 72 #include <net/sock.h> 73 #include <linux/seq_file.h> 74 75 #include <asm/uaccess.h> 76 77 /* Uncomment to enable debugging */ 78 /* #define TUN_DEBUG 1 */ 79 80 #ifdef TUN_DEBUG 81 static int debug; 82 83 #define tun_debug(level, tun, fmt, args...) \ 84 do { \ 85 if (tun->debug) \ 86 netdev_printk(level, tun->dev, fmt, ##args); \ 87 } while (0) 88 #define DBG1(level, fmt, args...) \ 89 do { \ 90 if (debug == 2) \ 91 printk(level fmt, ##args); \ 92 } while (0) 93 #else 94 #define tun_debug(level, tun, fmt, args...) \ 95 do { \ 96 if (0) \ 97 netdev_printk(level, tun->dev, fmt, ##args); \ 98 } while (0) 99 #define DBG1(level, fmt, args...) \ 100 do { \ 101 if (0) \ 102 printk(level fmt, ##args); \ 103 } while (0) 104 #endif 105 106 #define GOODCOPY_LEN 128 107 108 #define FLT_EXACT_COUNT 8 109 struct tap_filter { 110 unsigned int count; /* Number of addrs. Zero means disabled */ 111 u32 mask[2]; /* Mask of the hashed addrs */ 112 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 113 }; 114 115 /* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for 116 * the netdevice to be fit in one page. So we can make sure the success of 117 * memory allocation. TODO: increase the limit. */ 118 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES 119 #define MAX_TAP_FLOWS 4096 120 121 #define TUN_FLOW_EXPIRE (3 * HZ) 122 123 /* A tun_file connects an open character device to a tuntap netdevice. It 124 * also contains all socket related structures (except sock_fprog and tap_filter) 125 * to serve as one transmit queue for tuntap device. The sock_fprog and 126 * tap_filter were kept in tun_struct since they were used for filtering for the 127 * netdevice not for a specific queue (at least I didn't see the requirement for 128 * this). 129 * 130 * RCU usage: 131 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 132 * other can only be read while rcu_read_lock or rtnl_lock is held. 133 */ 134 struct tun_file { 135 struct sock sk; 136 struct socket socket; 137 struct socket_wq wq; 138 struct tun_struct __rcu *tun; 139 struct net *net; 140 struct fasync_struct *fasync; 141 /* only used for fasnyc */ 142 unsigned int flags; 143 union { 144 u16 queue_index; 145 unsigned int ifindex; 146 }; 147 struct list_head next; 148 struct tun_struct *detached; 149 }; 150 151 struct tun_flow_entry { 152 struct hlist_node hash_link; 153 struct rcu_head rcu; 154 struct tun_struct *tun; 155 156 u32 rxhash; 157 u32 rps_rxhash; 158 int queue_index; 159 unsigned long updated; 160 }; 161 162 #define TUN_NUM_FLOW_ENTRIES 1024 163 164 /* Since the socket were moved to tun_file, to preserve the behavior of persist 165 * device, socket filter, sndbuf and vnet header size were restore when the 166 * file were attached to a persist device. 167 */ 168 struct tun_struct { 169 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 170 unsigned int numqueues; 171 unsigned int flags; 172 kuid_t owner; 173 kgid_t group; 174 175 struct net_device *dev; 176 netdev_features_t set_features; 177 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 178 NETIF_F_TSO6) 179 180 int vnet_hdr_sz; 181 int sndbuf; 182 struct tap_filter txflt; 183 struct sock_fprog fprog; 184 /* protected by rtnl lock */ 185 bool filter_attached; 186 #ifdef TUN_DEBUG 187 int debug; 188 #endif 189 spinlock_t lock; 190 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 191 struct timer_list flow_gc_timer; 192 unsigned long ageing_time; 193 unsigned int numdisabled; 194 struct list_head disabled; 195 void *security; 196 u32 flow_count; 197 }; 198 199 static inline u32 tun_hashfn(u32 rxhash) 200 { 201 return rxhash & 0x3ff; 202 } 203 204 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 205 { 206 struct tun_flow_entry *e; 207 208 hlist_for_each_entry_rcu(e, head, hash_link) { 209 if (e->rxhash == rxhash) 210 return e; 211 } 212 return NULL; 213 } 214 215 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 216 struct hlist_head *head, 217 u32 rxhash, u16 queue_index) 218 { 219 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 220 221 if (e) { 222 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 223 rxhash, queue_index); 224 e->updated = jiffies; 225 e->rxhash = rxhash; 226 e->rps_rxhash = 0; 227 e->queue_index = queue_index; 228 e->tun = tun; 229 hlist_add_head_rcu(&e->hash_link, head); 230 ++tun->flow_count; 231 } 232 return e; 233 } 234 235 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 236 { 237 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 238 e->rxhash, e->queue_index); 239 sock_rps_reset_flow_hash(e->rps_rxhash); 240 hlist_del_rcu(&e->hash_link); 241 kfree_rcu(e, rcu); 242 --tun->flow_count; 243 } 244 245 static void tun_flow_flush(struct tun_struct *tun) 246 { 247 int i; 248 249 spin_lock_bh(&tun->lock); 250 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 251 struct tun_flow_entry *e; 252 struct hlist_node *n; 253 254 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 255 tun_flow_delete(tun, e); 256 } 257 spin_unlock_bh(&tun->lock); 258 } 259 260 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 261 { 262 int i; 263 264 spin_lock_bh(&tun->lock); 265 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 266 struct tun_flow_entry *e; 267 struct hlist_node *n; 268 269 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 270 if (e->queue_index == queue_index) 271 tun_flow_delete(tun, e); 272 } 273 } 274 spin_unlock_bh(&tun->lock); 275 } 276 277 static void tun_flow_cleanup(unsigned long data) 278 { 279 struct tun_struct *tun = (struct tun_struct *)data; 280 unsigned long delay = tun->ageing_time; 281 unsigned long next_timer = jiffies + delay; 282 unsigned long count = 0; 283 int i; 284 285 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 286 287 spin_lock_bh(&tun->lock); 288 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 289 struct tun_flow_entry *e; 290 struct hlist_node *n; 291 292 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 293 unsigned long this_timer; 294 count++; 295 this_timer = e->updated + delay; 296 if (time_before_eq(this_timer, jiffies)) 297 tun_flow_delete(tun, e); 298 else if (time_before(this_timer, next_timer)) 299 next_timer = this_timer; 300 } 301 } 302 303 if (count) 304 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 305 spin_unlock_bh(&tun->lock); 306 } 307 308 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 309 struct tun_file *tfile) 310 { 311 struct hlist_head *head; 312 struct tun_flow_entry *e; 313 unsigned long delay = tun->ageing_time; 314 u16 queue_index = tfile->queue_index; 315 316 if (!rxhash) 317 return; 318 else 319 head = &tun->flows[tun_hashfn(rxhash)]; 320 321 rcu_read_lock(); 322 323 /* We may get a very small possibility of OOO during switching, not 324 * worth to optimize.*/ 325 if (tun->numqueues == 1 || tfile->detached) 326 goto unlock; 327 328 e = tun_flow_find(head, rxhash); 329 if (likely(e)) { 330 /* TODO: keep queueing to old queue until it's empty? */ 331 e->queue_index = queue_index; 332 e->updated = jiffies; 333 sock_rps_record_flow_hash(e->rps_rxhash); 334 } else { 335 spin_lock_bh(&tun->lock); 336 if (!tun_flow_find(head, rxhash) && 337 tun->flow_count < MAX_TAP_FLOWS) 338 tun_flow_create(tun, head, rxhash, queue_index); 339 340 if (!timer_pending(&tun->flow_gc_timer)) 341 mod_timer(&tun->flow_gc_timer, 342 round_jiffies_up(jiffies + delay)); 343 spin_unlock_bh(&tun->lock); 344 } 345 346 unlock: 347 rcu_read_unlock(); 348 } 349 350 /** 351 * Save the hash received in the stack receive path and update the 352 * flow_hash table accordingly. 353 */ 354 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 355 { 356 if (unlikely(e->rps_rxhash != hash)) { 357 sock_rps_reset_flow_hash(e->rps_rxhash); 358 e->rps_rxhash = hash; 359 } 360 } 361 362 /* We try to identify a flow through its rxhash first. The reason that 363 * we do not check rxq no. is because some cards(e.g 82599), chooses 364 * the rxq based on the txq where the last packet of the flow comes. As 365 * the userspace application move between processors, we may get a 366 * different rxq no. here. If we could not get rxhash, then we would 367 * hope the rxq no. may help here. 368 */ 369 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, 370 void *accel_priv, select_queue_fallback_t fallback) 371 { 372 struct tun_struct *tun = netdev_priv(dev); 373 struct tun_flow_entry *e; 374 u32 txq = 0; 375 u32 numqueues = 0; 376 377 rcu_read_lock(); 378 numqueues = ACCESS_ONCE(tun->numqueues); 379 380 txq = skb_get_hash(skb); 381 if (txq) { 382 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 383 if (e) { 384 tun_flow_save_rps_rxhash(e, txq); 385 txq = e->queue_index; 386 } else 387 /* use multiply and shift instead of expensive divide */ 388 txq = ((u64)txq * numqueues) >> 32; 389 } else if (likely(skb_rx_queue_recorded(skb))) { 390 txq = skb_get_rx_queue(skb); 391 while (unlikely(txq >= numqueues)) 392 txq -= numqueues; 393 } 394 395 rcu_read_unlock(); 396 return txq; 397 } 398 399 static inline bool tun_not_capable(struct tun_struct *tun) 400 { 401 const struct cred *cred = current_cred(); 402 struct net *net = dev_net(tun->dev); 403 404 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 405 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 406 !ns_capable(net->user_ns, CAP_NET_ADMIN); 407 } 408 409 static void tun_set_real_num_queues(struct tun_struct *tun) 410 { 411 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 412 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 413 } 414 415 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 416 { 417 tfile->detached = tun; 418 list_add_tail(&tfile->next, &tun->disabled); 419 ++tun->numdisabled; 420 } 421 422 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 423 { 424 struct tun_struct *tun = tfile->detached; 425 426 tfile->detached = NULL; 427 list_del_init(&tfile->next); 428 --tun->numdisabled; 429 return tun; 430 } 431 432 static void tun_queue_purge(struct tun_file *tfile) 433 { 434 skb_queue_purge(&tfile->sk.sk_receive_queue); 435 skb_queue_purge(&tfile->sk.sk_error_queue); 436 } 437 438 static void __tun_detach(struct tun_file *tfile, bool clean) 439 { 440 struct tun_file *ntfile; 441 struct tun_struct *tun; 442 443 tun = rtnl_dereference(tfile->tun); 444 445 if (tun && !tfile->detached) { 446 u16 index = tfile->queue_index; 447 BUG_ON(index >= tun->numqueues); 448 449 rcu_assign_pointer(tun->tfiles[index], 450 tun->tfiles[tun->numqueues - 1]); 451 ntfile = rtnl_dereference(tun->tfiles[index]); 452 ntfile->queue_index = index; 453 454 --tun->numqueues; 455 if (clean) { 456 RCU_INIT_POINTER(tfile->tun, NULL); 457 sock_put(&tfile->sk); 458 } else 459 tun_disable_queue(tun, tfile); 460 461 synchronize_net(); 462 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 463 /* Drop read queue */ 464 tun_queue_purge(tfile); 465 tun_set_real_num_queues(tun); 466 } else if (tfile->detached && clean) { 467 tun = tun_enable_queue(tfile); 468 sock_put(&tfile->sk); 469 } 470 471 if (clean) { 472 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 473 netif_carrier_off(tun->dev); 474 475 if (!(tun->flags & TUN_PERSIST) && 476 tun->dev->reg_state == NETREG_REGISTERED) 477 unregister_netdevice(tun->dev); 478 } 479 480 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 481 &tfile->socket.flags)); 482 sk_release_kernel(&tfile->sk); 483 } 484 } 485 486 static void tun_detach(struct tun_file *tfile, bool clean) 487 { 488 rtnl_lock(); 489 __tun_detach(tfile, clean); 490 rtnl_unlock(); 491 } 492 493 static void tun_detach_all(struct net_device *dev) 494 { 495 struct tun_struct *tun = netdev_priv(dev); 496 struct tun_file *tfile, *tmp; 497 int i, n = tun->numqueues; 498 499 for (i = 0; i < n; i++) { 500 tfile = rtnl_dereference(tun->tfiles[i]); 501 BUG_ON(!tfile); 502 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 503 RCU_INIT_POINTER(tfile->tun, NULL); 504 --tun->numqueues; 505 } 506 list_for_each_entry(tfile, &tun->disabled, next) { 507 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 508 RCU_INIT_POINTER(tfile->tun, NULL); 509 } 510 BUG_ON(tun->numqueues != 0); 511 512 synchronize_net(); 513 for (i = 0; i < n; i++) { 514 tfile = rtnl_dereference(tun->tfiles[i]); 515 /* Drop read queue */ 516 tun_queue_purge(tfile); 517 sock_put(&tfile->sk); 518 } 519 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 520 tun_enable_queue(tfile); 521 tun_queue_purge(tfile); 522 sock_put(&tfile->sk); 523 } 524 BUG_ON(tun->numdisabled != 0); 525 526 if (tun->flags & TUN_PERSIST) 527 module_put(THIS_MODULE); 528 } 529 530 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) 531 { 532 struct tun_file *tfile = file->private_data; 533 int err; 534 535 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 536 if (err < 0) 537 goto out; 538 539 err = -EINVAL; 540 if (rtnl_dereference(tfile->tun) && !tfile->detached) 541 goto out; 542 543 err = -EBUSY; 544 if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1) 545 goto out; 546 547 err = -E2BIG; 548 if (!tfile->detached && 549 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 550 goto out; 551 552 err = 0; 553 554 /* Re-attach the filter to persist device */ 555 if (!skip_filter && (tun->filter_attached == true)) { 556 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 557 if (!err) 558 goto out; 559 } 560 tfile->queue_index = tun->numqueues; 561 rcu_assign_pointer(tfile->tun, tun); 562 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 563 tun->numqueues++; 564 565 if (tfile->detached) 566 tun_enable_queue(tfile); 567 else 568 sock_hold(&tfile->sk); 569 570 tun_set_real_num_queues(tun); 571 572 /* device is allowed to go away first, so no need to hold extra 573 * refcnt. 574 */ 575 576 out: 577 return err; 578 } 579 580 static struct tun_struct *__tun_get(struct tun_file *tfile) 581 { 582 struct tun_struct *tun; 583 584 rcu_read_lock(); 585 tun = rcu_dereference(tfile->tun); 586 if (tun) 587 dev_hold(tun->dev); 588 rcu_read_unlock(); 589 590 return tun; 591 } 592 593 static struct tun_struct *tun_get(struct file *file) 594 { 595 return __tun_get(file->private_data); 596 } 597 598 static void tun_put(struct tun_struct *tun) 599 { 600 dev_put(tun->dev); 601 } 602 603 /* TAP filtering */ 604 static void addr_hash_set(u32 *mask, const u8 *addr) 605 { 606 int n = ether_crc(ETH_ALEN, addr) >> 26; 607 mask[n >> 5] |= (1 << (n & 31)); 608 } 609 610 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 611 { 612 int n = ether_crc(ETH_ALEN, addr) >> 26; 613 return mask[n >> 5] & (1 << (n & 31)); 614 } 615 616 static int update_filter(struct tap_filter *filter, void __user *arg) 617 { 618 struct { u8 u[ETH_ALEN]; } *addr; 619 struct tun_filter uf; 620 int err, alen, n, nexact; 621 622 if (copy_from_user(&uf, arg, sizeof(uf))) 623 return -EFAULT; 624 625 if (!uf.count) { 626 /* Disabled */ 627 filter->count = 0; 628 return 0; 629 } 630 631 alen = ETH_ALEN * uf.count; 632 addr = kmalloc(alen, GFP_KERNEL); 633 if (!addr) 634 return -ENOMEM; 635 636 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 637 err = -EFAULT; 638 goto done; 639 } 640 641 /* The filter is updated without holding any locks. Which is 642 * perfectly safe. We disable it first and in the worst 643 * case we'll accept a few undesired packets. */ 644 filter->count = 0; 645 wmb(); 646 647 /* Use first set of addresses as an exact filter */ 648 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 649 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 650 651 nexact = n; 652 653 /* Remaining multicast addresses are hashed, 654 * unicast will leave the filter disabled. */ 655 memset(filter->mask, 0, sizeof(filter->mask)); 656 for (; n < uf.count; n++) { 657 if (!is_multicast_ether_addr(addr[n].u)) { 658 err = 0; /* no filter */ 659 goto done; 660 } 661 addr_hash_set(filter->mask, addr[n].u); 662 } 663 664 /* For ALLMULTI just set the mask to all ones. 665 * This overrides the mask populated above. */ 666 if ((uf.flags & TUN_FLT_ALLMULTI)) 667 memset(filter->mask, ~0, sizeof(filter->mask)); 668 669 /* Now enable the filter */ 670 wmb(); 671 filter->count = nexact; 672 673 /* Return the number of exact filters */ 674 err = nexact; 675 676 done: 677 kfree(addr); 678 return err; 679 } 680 681 /* Returns: 0 - drop, !=0 - accept */ 682 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 683 { 684 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 685 * at this point. */ 686 struct ethhdr *eh = (struct ethhdr *) skb->data; 687 int i; 688 689 /* Exact match */ 690 for (i = 0; i < filter->count; i++) 691 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 692 return 1; 693 694 /* Inexact match (multicast only) */ 695 if (is_multicast_ether_addr(eh->h_dest)) 696 return addr_hash_test(filter->mask, eh->h_dest); 697 698 return 0; 699 } 700 701 /* 702 * Checks whether the packet is accepted or not. 703 * Returns: 0 - drop, !=0 - accept 704 */ 705 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 706 { 707 if (!filter->count) 708 return 1; 709 710 return run_filter(filter, skb); 711 } 712 713 /* Network device part of the driver */ 714 715 static const struct ethtool_ops tun_ethtool_ops; 716 717 /* Net device detach from fd. */ 718 static void tun_net_uninit(struct net_device *dev) 719 { 720 tun_detach_all(dev); 721 } 722 723 /* Net device open. */ 724 static int tun_net_open(struct net_device *dev) 725 { 726 netif_tx_start_all_queues(dev); 727 return 0; 728 } 729 730 /* Net device close. */ 731 static int tun_net_close(struct net_device *dev) 732 { 733 netif_tx_stop_all_queues(dev); 734 return 0; 735 } 736 737 /* Net device start xmit */ 738 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 739 { 740 struct tun_struct *tun = netdev_priv(dev); 741 int txq = skb->queue_mapping; 742 struct tun_file *tfile; 743 u32 numqueues = 0; 744 745 rcu_read_lock(); 746 tfile = rcu_dereference(tun->tfiles[txq]); 747 numqueues = ACCESS_ONCE(tun->numqueues); 748 749 /* Drop packet if interface is not attached */ 750 if (txq >= numqueues) 751 goto drop; 752 753 if (numqueues == 1) { 754 /* Select queue was not called for the skbuff, so we extract the 755 * RPS hash and save it into the flow_table here. 756 */ 757 __u32 rxhash; 758 759 rxhash = skb_get_hash(skb); 760 if (rxhash) { 761 struct tun_flow_entry *e; 762 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], 763 rxhash); 764 if (e) 765 tun_flow_save_rps_rxhash(e, rxhash); 766 } 767 } 768 769 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 770 771 BUG_ON(!tfile); 772 773 /* Drop if the filter does not like it. 774 * This is a noop if the filter is disabled. 775 * Filter can be enabled only for the TAP devices. */ 776 if (!check_filter(&tun->txflt, skb)) 777 goto drop; 778 779 if (tfile->socket.sk->sk_filter && 780 sk_filter(tfile->socket.sk, skb)) 781 goto drop; 782 783 /* Limit the number of packets queued by dividing txq length with the 784 * number of queues. 785 */ 786 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues 787 >= dev->tx_queue_len) 788 goto drop; 789 790 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 791 goto drop; 792 793 if (skb->sk) { 794 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags); 795 sw_tx_timestamp(skb); 796 } 797 798 /* Orphan the skb - required as we might hang on to it 799 * for indefinite time. 800 */ 801 skb_orphan(skb); 802 803 nf_reset(skb); 804 805 /* Enqueue packet */ 806 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 807 808 /* Notify and wake up reader process */ 809 if (tfile->flags & TUN_FASYNC) 810 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 811 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 812 813 rcu_read_unlock(); 814 return NETDEV_TX_OK; 815 816 drop: 817 dev->stats.tx_dropped++; 818 skb_tx_error(skb); 819 kfree_skb(skb); 820 rcu_read_unlock(); 821 return NETDEV_TX_OK; 822 } 823 824 static void tun_net_mclist(struct net_device *dev) 825 { 826 /* 827 * This callback is supposed to deal with mc filter in 828 * _rx_ path and has nothing to do with the _tx_ path. 829 * In rx path we always accept everything userspace gives us. 830 */ 831 } 832 833 #define MIN_MTU 68 834 #define MAX_MTU 65535 835 836 static int 837 tun_net_change_mtu(struct net_device *dev, int new_mtu) 838 { 839 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 840 return -EINVAL; 841 dev->mtu = new_mtu; 842 return 0; 843 } 844 845 static netdev_features_t tun_net_fix_features(struct net_device *dev, 846 netdev_features_t features) 847 { 848 struct tun_struct *tun = netdev_priv(dev); 849 850 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 851 } 852 #ifdef CONFIG_NET_POLL_CONTROLLER 853 static void tun_poll_controller(struct net_device *dev) 854 { 855 /* 856 * Tun only receives frames when: 857 * 1) the char device endpoint gets data from user space 858 * 2) the tun socket gets a sendmsg call from user space 859 * Since both of those are synchronous operations, we are guaranteed 860 * never to have pending data when we poll for it 861 * so there is nothing to do here but return. 862 * We need this though so netpoll recognizes us as an interface that 863 * supports polling, which enables bridge devices in virt setups to 864 * still use netconsole 865 */ 866 return; 867 } 868 #endif 869 static const struct net_device_ops tun_netdev_ops = { 870 .ndo_uninit = tun_net_uninit, 871 .ndo_open = tun_net_open, 872 .ndo_stop = tun_net_close, 873 .ndo_start_xmit = tun_net_xmit, 874 .ndo_change_mtu = tun_net_change_mtu, 875 .ndo_fix_features = tun_net_fix_features, 876 .ndo_select_queue = tun_select_queue, 877 #ifdef CONFIG_NET_POLL_CONTROLLER 878 .ndo_poll_controller = tun_poll_controller, 879 #endif 880 }; 881 882 static const struct net_device_ops tap_netdev_ops = { 883 .ndo_uninit = tun_net_uninit, 884 .ndo_open = tun_net_open, 885 .ndo_stop = tun_net_close, 886 .ndo_start_xmit = tun_net_xmit, 887 .ndo_change_mtu = tun_net_change_mtu, 888 .ndo_fix_features = tun_net_fix_features, 889 .ndo_set_rx_mode = tun_net_mclist, 890 .ndo_set_mac_address = eth_mac_addr, 891 .ndo_validate_addr = eth_validate_addr, 892 .ndo_select_queue = tun_select_queue, 893 #ifdef CONFIG_NET_POLL_CONTROLLER 894 .ndo_poll_controller = tun_poll_controller, 895 #endif 896 }; 897 898 static void tun_flow_init(struct tun_struct *tun) 899 { 900 int i; 901 902 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 903 INIT_HLIST_HEAD(&tun->flows[i]); 904 905 tun->ageing_time = TUN_FLOW_EXPIRE; 906 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 907 mod_timer(&tun->flow_gc_timer, 908 round_jiffies_up(jiffies + tun->ageing_time)); 909 } 910 911 static void tun_flow_uninit(struct tun_struct *tun) 912 { 913 del_timer_sync(&tun->flow_gc_timer); 914 tun_flow_flush(tun); 915 } 916 917 /* Initialize net device. */ 918 static void tun_net_init(struct net_device *dev) 919 { 920 struct tun_struct *tun = netdev_priv(dev); 921 922 switch (tun->flags & TUN_TYPE_MASK) { 923 case TUN_TUN_DEV: 924 dev->netdev_ops = &tun_netdev_ops; 925 926 /* Point-to-Point TUN Device */ 927 dev->hard_header_len = 0; 928 dev->addr_len = 0; 929 dev->mtu = 1500; 930 931 /* Zero header length */ 932 dev->type = ARPHRD_NONE; 933 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 934 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 935 break; 936 937 case TUN_TAP_DEV: 938 dev->netdev_ops = &tap_netdev_ops; 939 /* Ethernet TAP Device */ 940 ether_setup(dev); 941 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 942 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 943 944 eth_hw_addr_random(dev); 945 946 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 947 break; 948 } 949 } 950 951 /* Character device part */ 952 953 /* Poll */ 954 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 955 { 956 struct tun_file *tfile = file->private_data; 957 struct tun_struct *tun = __tun_get(tfile); 958 struct sock *sk; 959 unsigned int mask = 0; 960 961 if (!tun) 962 return POLLERR; 963 964 sk = tfile->socket.sk; 965 966 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 967 968 poll_wait(file, sk_sleep(sk), wait); 969 970 if (!skb_queue_empty(&sk->sk_receive_queue)) 971 mask |= POLLIN | POLLRDNORM; 972 973 if (sock_writeable(sk) || 974 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 975 sock_writeable(sk))) 976 mask |= POLLOUT | POLLWRNORM; 977 978 if (tun->dev->reg_state != NETREG_REGISTERED) 979 mask = POLLERR; 980 981 tun_put(tun); 982 return mask; 983 } 984 985 /* prepad is the amount to reserve at front. len is length after that. 986 * linear is a hint as to how much to copy (usually headers). */ 987 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 988 size_t prepad, size_t len, 989 size_t linear, int noblock) 990 { 991 struct sock *sk = tfile->socket.sk; 992 struct sk_buff *skb; 993 int err; 994 995 /* Under a page? Don't bother with paged skb. */ 996 if (prepad + len < PAGE_SIZE || !linear) 997 linear = len; 998 999 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 1000 &err, 0); 1001 if (!skb) 1002 return ERR_PTR(err); 1003 1004 skb_reserve(skb, prepad); 1005 skb_put(skb, linear); 1006 skb->data_len = len - linear; 1007 skb->len += len - linear; 1008 1009 return skb; 1010 } 1011 1012 /* Get packet from user space buffer */ 1013 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1014 void *msg_control, const struct iovec *iv, 1015 size_t total_len, size_t count, int noblock) 1016 { 1017 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1018 struct sk_buff *skb; 1019 size_t len = total_len, align = NET_SKB_PAD, linear; 1020 struct virtio_net_hdr gso = { 0 }; 1021 int good_linear; 1022 int offset = 0; 1023 int copylen; 1024 bool zerocopy = false; 1025 int err; 1026 u32 rxhash; 1027 1028 if (!(tun->flags & TUN_NO_PI)) { 1029 if (len < sizeof(pi)) 1030 return -EINVAL; 1031 len -= sizeof(pi); 1032 1033 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) 1034 return -EFAULT; 1035 offset += sizeof(pi); 1036 } 1037 1038 if (tun->flags & TUN_VNET_HDR) { 1039 if (len < tun->vnet_hdr_sz) 1040 return -EINVAL; 1041 len -= tun->vnet_hdr_sz; 1042 1043 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) 1044 return -EFAULT; 1045 1046 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1047 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) 1048 gso.hdr_len = gso.csum_start + gso.csum_offset + 2; 1049 1050 if (gso.hdr_len > len) 1051 return -EINVAL; 1052 offset += tun->vnet_hdr_sz; 1053 } 1054 1055 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { 1056 align += NET_IP_ALIGN; 1057 if (unlikely(len < ETH_HLEN || 1058 (gso.hdr_len && gso.hdr_len < ETH_HLEN))) 1059 return -EINVAL; 1060 } 1061 1062 good_linear = SKB_MAX_HEAD(align); 1063 1064 if (msg_control) { 1065 /* There are 256 bytes to be copied in skb, so there is 1066 * enough room for skb expand head in case it is used. 1067 * The rest of the buffer is mapped from userspace. 1068 */ 1069 copylen = gso.hdr_len ? gso.hdr_len : GOODCOPY_LEN; 1070 if (copylen > good_linear) 1071 copylen = good_linear; 1072 linear = copylen; 1073 if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS) 1074 zerocopy = true; 1075 } 1076 1077 if (!zerocopy) { 1078 copylen = len; 1079 if (gso.hdr_len > good_linear) 1080 linear = good_linear; 1081 else 1082 linear = gso.hdr_len; 1083 } 1084 1085 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1086 if (IS_ERR(skb)) { 1087 if (PTR_ERR(skb) != -EAGAIN) 1088 tun->dev->stats.rx_dropped++; 1089 return PTR_ERR(skb); 1090 } 1091 1092 if (zerocopy) 1093 err = zerocopy_sg_from_iovec(skb, iv, offset, count); 1094 else { 1095 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len); 1096 if (!err && msg_control) { 1097 struct ubuf_info *uarg = msg_control; 1098 uarg->callback(uarg, false); 1099 } 1100 } 1101 1102 if (err) { 1103 tun->dev->stats.rx_dropped++; 1104 kfree_skb(skb); 1105 return -EFAULT; 1106 } 1107 1108 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1109 if (!skb_partial_csum_set(skb, gso.csum_start, 1110 gso.csum_offset)) { 1111 tun->dev->stats.rx_frame_errors++; 1112 kfree_skb(skb); 1113 return -EINVAL; 1114 } 1115 } 1116 1117 switch (tun->flags & TUN_TYPE_MASK) { 1118 case TUN_TUN_DEV: 1119 if (tun->flags & TUN_NO_PI) { 1120 switch (skb->data[0] & 0xf0) { 1121 case 0x40: 1122 pi.proto = htons(ETH_P_IP); 1123 break; 1124 case 0x60: 1125 pi.proto = htons(ETH_P_IPV6); 1126 break; 1127 default: 1128 tun->dev->stats.rx_dropped++; 1129 kfree_skb(skb); 1130 return -EINVAL; 1131 } 1132 } 1133 1134 skb_reset_mac_header(skb); 1135 skb->protocol = pi.proto; 1136 skb->dev = tun->dev; 1137 break; 1138 case TUN_TAP_DEV: 1139 skb->protocol = eth_type_trans(skb, tun->dev); 1140 break; 1141 } 1142 1143 skb_reset_network_header(skb); 1144 1145 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1146 pr_debug("GSO!\n"); 1147 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1148 case VIRTIO_NET_HDR_GSO_TCPV4: 1149 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1150 break; 1151 case VIRTIO_NET_HDR_GSO_TCPV6: 1152 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1153 break; 1154 case VIRTIO_NET_HDR_GSO_UDP: 1155 { 1156 static bool warned; 1157 1158 if (!warned) { 1159 warned = true; 1160 netdev_warn(tun->dev, 1161 "%s: using disabled UFO feature; please fix this program\n", 1162 current->comm); 1163 } 1164 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1165 if (skb->protocol == htons(ETH_P_IPV6)) 1166 ipv6_proxy_select_ident(skb); 1167 break; 1168 } 1169 default: 1170 tun->dev->stats.rx_frame_errors++; 1171 kfree_skb(skb); 1172 return -EINVAL; 1173 } 1174 1175 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1176 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1177 1178 skb_shinfo(skb)->gso_size = gso.gso_size; 1179 if (skb_shinfo(skb)->gso_size == 0) { 1180 tun->dev->stats.rx_frame_errors++; 1181 kfree_skb(skb); 1182 return -EINVAL; 1183 } 1184 1185 /* Header must be checked, and gso_segs computed. */ 1186 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1187 skb_shinfo(skb)->gso_segs = 0; 1188 } 1189 1190 /* copy skb_ubuf_info for callback when skb has no error */ 1191 if (zerocopy) { 1192 skb_shinfo(skb)->destructor_arg = msg_control; 1193 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1194 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1195 } 1196 1197 skb_probe_transport_header(skb, 0); 1198 1199 rxhash = skb_get_hash(skb); 1200 netif_rx_ni(skb); 1201 1202 tun->dev->stats.rx_packets++; 1203 tun->dev->stats.rx_bytes += len; 1204 1205 tun_flow_update(tun, rxhash, tfile); 1206 return total_len; 1207 } 1208 1209 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 1210 unsigned long count, loff_t pos) 1211 { 1212 struct file *file = iocb->ki_filp; 1213 struct tun_struct *tun = tun_get(file); 1214 struct tun_file *tfile = file->private_data; 1215 ssize_t result; 1216 1217 if (!tun) 1218 return -EBADFD; 1219 1220 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count); 1221 1222 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count), 1223 count, file->f_flags & O_NONBLOCK); 1224 1225 tun_put(tun); 1226 return result; 1227 } 1228 1229 /* Put packet to the user space buffer */ 1230 static ssize_t tun_put_user(struct tun_struct *tun, 1231 struct tun_file *tfile, 1232 struct sk_buff *skb, 1233 const struct iovec *iv, int len) 1234 { 1235 struct tun_pi pi = { 0, skb->protocol }; 1236 ssize_t total = 0; 1237 int vlan_offset = 0, copied; 1238 1239 if (!(tun->flags & TUN_NO_PI)) { 1240 if ((len -= sizeof(pi)) < 0) 1241 return -EINVAL; 1242 1243 if (len < skb->len) { 1244 /* Packet will be striped */ 1245 pi.flags |= TUN_PKT_STRIP; 1246 } 1247 1248 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi))) 1249 return -EFAULT; 1250 total += sizeof(pi); 1251 } 1252 1253 if (tun->flags & TUN_VNET_HDR) { 1254 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1255 if ((len -= tun->vnet_hdr_sz) < 0) 1256 return -EINVAL; 1257 1258 if (skb_is_gso(skb)) { 1259 struct skb_shared_info *sinfo = skb_shinfo(skb); 1260 1261 /* This is a hint as to how much should be linear. */ 1262 gso.hdr_len = skb_headlen(skb); 1263 gso.gso_size = sinfo->gso_size; 1264 if (sinfo->gso_type & SKB_GSO_TCPV4) 1265 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1266 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1267 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1268 else { 1269 pr_err("unexpected GSO type: " 1270 "0x%x, gso_size %d, hdr_len %d\n", 1271 sinfo->gso_type, gso.gso_size, 1272 gso.hdr_len); 1273 print_hex_dump(KERN_ERR, "tun: ", 1274 DUMP_PREFIX_NONE, 1275 16, 1, skb->head, 1276 min((int)gso.hdr_len, 64), true); 1277 WARN_ON_ONCE(1); 1278 return -EINVAL; 1279 } 1280 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1281 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1282 } else 1283 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1284 1285 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1286 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1287 gso.csum_start = skb_checksum_start_offset(skb); 1288 gso.csum_offset = skb->csum_offset; 1289 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1290 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1291 } /* else everything is zero */ 1292 1293 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, 1294 sizeof(gso)))) 1295 return -EFAULT; 1296 total += tun->vnet_hdr_sz; 1297 } 1298 1299 copied = total; 1300 total += skb->len; 1301 if (!vlan_tx_tag_present(skb)) { 1302 len = min_t(int, skb->len, len); 1303 } else { 1304 int copy, ret; 1305 struct { 1306 __be16 h_vlan_proto; 1307 __be16 h_vlan_TCI; 1308 } veth; 1309 1310 veth.h_vlan_proto = skb->vlan_proto; 1311 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 1312 1313 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1314 len = min_t(int, skb->len + VLAN_HLEN, len); 1315 total += VLAN_HLEN; 1316 1317 copy = min_t(int, vlan_offset, len); 1318 ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); 1319 len -= copy; 1320 copied += copy; 1321 if (ret || !len) 1322 goto done; 1323 1324 copy = min_t(int, sizeof(veth), len); 1325 ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy); 1326 len -= copy; 1327 copied += copy; 1328 if (ret || !len) 1329 goto done; 1330 } 1331 1332 skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len); 1333 1334 done: 1335 tun->dev->stats.tx_packets++; 1336 tun->dev->stats.tx_bytes += len; 1337 1338 return total; 1339 } 1340 1341 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1342 const struct iovec *iv, ssize_t len, int noblock) 1343 { 1344 struct sk_buff *skb; 1345 ssize_t ret = 0; 1346 int peeked, err, off = 0; 1347 1348 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1349 1350 if (!len) 1351 return ret; 1352 1353 if (tun->dev->reg_state != NETREG_REGISTERED) 1354 return -EIO; 1355 1356 /* Read frames from queue */ 1357 skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0, 1358 &peeked, &off, &err); 1359 if (skb) { 1360 ret = tun_put_user(tun, tfile, skb, iv, len); 1361 kfree_skb(skb); 1362 } else 1363 ret = err; 1364 1365 return ret; 1366 } 1367 1368 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 1369 unsigned long count, loff_t pos) 1370 { 1371 struct file *file = iocb->ki_filp; 1372 struct tun_file *tfile = file->private_data; 1373 struct tun_struct *tun = __tun_get(tfile); 1374 ssize_t len, ret; 1375 1376 if (!tun) 1377 return -EBADFD; 1378 len = iov_length(iv, count); 1379 if (len < 0) { 1380 ret = -EINVAL; 1381 goto out; 1382 } 1383 1384 ret = tun_do_read(tun, tfile, iv, len, 1385 file->f_flags & O_NONBLOCK); 1386 ret = min_t(ssize_t, ret, len); 1387 if (ret > 0) 1388 iocb->ki_pos = ret; 1389 out: 1390 tun_put(tun); 1391 return ret; 1392 } 1393 1394 static void tun_free_netdev(struct net_device *dev) 1395 { 1396 struct tun_struct *tun = netdev_priv(dev); 1397 1398 BUG_ON(!(list_empty(&tun->disabled))); 1399 tun_flow_uninit(tun); 1400 security_tun_dev_free_security(tun->security); 1401 free_netdev(dev); 1402 } 1403 1404 static void tun_setup(struct net_device *dev) 1405 { 1406 struct tun_struct *tun = netdev_priv(dev); 1407 1408 tun->owner = INVALID_UID; 1409 tun->group = INVALID_GID; 1410 1411 dev->ethtool_ops = &tun_ethtool_ops; 1412 dev->destructor = tun_free_netdev; 1413 } 1414 1415 /* Trivial set of netlink ops to allow deleting tun or tap 1416 * device with netlink. 1417 */ 1418 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1419 { 1420 return -EINVAL; 1421 } 1422 1423 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1424 .kind = DRV_NAME, 1425 .priv_size = sizeof(struct tun_struct), 1426 .setup = tun_setup, 1427 .validate = tun_validate, 1428 }; 1429 1430 static void tun_sock_write_space(struct sock *sk) 1431 { 1432 struct tun_file *tfile; 1433 wait_queue_head_t *wqueue; 1434 1435 if (!sock_writeable(sk)) 1436 return; 1437 1438 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1439 return; 1440 1441 wqueue = sk_sleep(sk); 1442 if (wqueue && waitqueue_active(wqueue)) 1443 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1444 POLLWRNORM | POLLWRBAND); 1445 1446 tfile = container_of(sk, struct tun_file, sk); 1447 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1448 } 1449 1450 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1451 struct msghdr *m, size_t total_len) 1452 { 1453 int ret; 1454 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1455 struct tun_struct *tun = __tun_get(tfile); 1456 1457 if (!tun) 1458 return -EBADFD; 1459 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len, 1460 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); 1461 tun_put(tun); 1462 return ret; 1463 } 1464 1465 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1466 struct msghdr *m, size_t total_len, 1467 int flags) 1468 { 1469 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1470 struct tun_struct *tun = __tun_get(tfile); 1471 int ret; 1472 1473 if (!tun) 1474 return -EBADFD; 1475 1476 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1477 ret = -EINVAL; 1478 goto out; 1479 } 1480 if (flags & MSG_ERRQUEUE) { 1481 ret = sock_recv_errqueue(sock->sk, m, total_len, 1482 SOL_PACKET, TUN_TX_TIMESTAMP); 1483 goto out; 1484 } 1485 ret = tun_do_read(tun, tfile, m->msg_iov, total_len, 1486 flags & MSG_DONTWAIT); 1487 if (ret > total_len) { 1488 m->msg_flags |= MSG_TRUNC; 1489 ret = flags & MSG_TRUNC ? ret : total_len; 1490 } 1491 out: 1492 tun_put(tun); 1493 return ret; 1494 } 1495 1496 static int tun_release(struct socket *sock) 1497 { 1498 if (sock->sk) 1499 sock_put(sock->sk); 1500 return 0; 1501 } 1502 1503 /* Ops structure to mimic raw sockets with tun */ 1504 static const struct proto_ops tun_socket_ops = { 1505 .sendmsg = tun_sendmsg, 1506 .recvmsg = tun_recvmsg, 1507 .release = tun_release, 1508 }; 1509 1510 static struct proto tun_proto = { 1511 .name = "tun", 1512 .owner = THIS_MODULE, 1513 .obj_size = sizeof(struct tun_file), 1514 }; 1515 1516 static int tun_flags(struct tun_struct *tun) 1517 { 1518 int flags = 0; 1519 1520 if (tun->flags & TUN_TUN_DEV) 1521 flags |= IFF_TUN; 1522 else 1523 flags |= IFF_TAP; 1524 1525 if (tun->flags & TUN_NO_PI) 1526 flags |= IFF_NO_PI; 1527 1528 /* This flag has no real effect. We track the value for backwards 1529 * compatibility. 1530 */ 1531 if (tun->flags & TUN_ONE_QUEUE) 1532 flags |= IFF_ONE_QUEUE; 1533 1534 if (tun->flags & TUN_VNET_HDR) 1535 flags |= IFF_VNET_HDR; 1536 1537 if (tun->flags & TUN_TAP_MQ) 1538 flags |= IFF_MULTI_QUEUE; 1539 1540 if (tun->flags & TUN_PERSIST) 1541 flags |= IFF_PERSIST; 1542 1543 return flags; 1544 } 1545 1546 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1547 char *buf) 1548 { 1549 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1550 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1551 } 1552 1553 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1554 char *buf) 1555 { 1556 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1557 return uid_valid(tun->owner)? 1558 sprintf(buf, "%u\n", 1559 from_kuid_munged(current_user_ns(), tun->owner)): 1560 sprintf(buf, "-1\n"); 1561 } 1562 1563 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1564 char *buf) 1565 { 1566 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1567 return gid_valid(tun->group) ? 1568 sprintf(buf, "%u\n", 1569 from_kgid_munged(current_user_ns(), tun->group)): 1570 sprintf(buf, "-1\n"); 1571 } 1572 1573 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1574 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1575 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1576 1577 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1578 { 1579 struct tun_struct *tun; 1580 struct tun_file *tfile = file->private_data; 1581 struct net_device *dev; 1582 int err; 1583 1584 if (tfile->detached) 1585 return -EINVAL; 1586 1587 dev = __dev_get_by_name(net, ifr->ifr_name); 1588 if (dev) { 1589 if (ifr->ifr_flags & IFF_TUN_EXCL) 1590 return -EBUSY; 1591 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1592 tun = netdev_priv(dev); 1593 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1594 tun = netdev_priv(dev); 1595 else 1596 return -EINVAL; 1597 1598 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1599 !!(tun->flags & TUN_TAP_MQ)) 1600 return -EINVAL; 1601 1602 if (tun_not_capable(tun)) 1603 return -EPERM; 1604 err = security_tun_dev_open(tun->security); 1605 if (err < 0) 1606 return err; 1607 1608 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1609 if (err < 0) 1610 return err; 1611 1612 if (tun->flags & TUN_TAP_MQ && 1613 (tun->numqueues + tun->numdisabled > 1)) { 1614 /* One or more queue has already been attached, no need 1615 * to initialize the device again. 1616 */ 1617 return 0; 1618 } 1619 } 1620 else { 1621 char *name; 1622 unsigned long flags = 0; 1623 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1624 MAX_TAP_QUEUES : 1; 1625 1626 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1627 return -EPERM; 1628 err = security_tun_dev_create(); 1629 if (err < 0) 1630 return err; 1631 1632 /* Set dev type */ 1633 if (ifr->ifr_flags & IFF_TUN) { 1634 /* TUN device */ 1635 flags |= TUN_TUN_DEV; 1636 name = "tun%d"; 1637 } else if (ifr->ifr_flags & IFF_TAP) { 1638 /* TAP device */ 1639 flags |= TUN_TAP_DEV; 1640 name = "tap%d"; 1641 } else 1642 return -EINVAL; 1643 1644 if (*ifr->ifr_name) 1645 name = ifr->ifr_name; 1646 1647 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1648 NET_NAME_UNKNOWN, tun_setup, queues, 1649 queues); 1650 1651 if (!dev) 1652 return -ENOMEM; 1653 1654 dev_net_set(dev, net); 1655 dev->rtnl_link_ops = &tun_link_ops; 1656 dev->ifindex = tfile->ifindex; 1657 1658 tun = netdev_priv(dev); 1659 tun->dev = dev; 1660 tun->flags = flags; 1661 tun->txflt.count = 0; 1662 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1663 1664 tun->filter_attached = false; 1665 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1666 1667 spin_lock_init(&tun->lock); 1668 1669 err = security_tun_dev_alloc_security(&tun->security); 1670 if (err < 0) 1671 goto err_free_dev; 1672 1673 tun_net_init(dev); 1674 tun_flow_init(tun); 1675 1676 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1677 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1678 NETIF_F_HW_VLAN_STAG_TX; 1679 dev->features = dev->hw_features; 1680 dev->vlan_features = dev->features & 1681 ~(NETIF_F_HW_VLAN_CTAG_TX | 1682 NETIF_F_HW_VLAN_STAG_TX); 1683 1684 INIT_LIST_HEAD(&tun->disabled); 1685 err = tun_attach(tun, file, false); 1686 if (err < 0) 1687 goto err_free_flow; 1688 1689 err = register_netdevice(tun->dev); 1690 if (err < 0) 1691 goto err_detach; 1692 1693 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1694 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1695 device_create_file(&tun->dev->dev, &dev_attr_group)) 1696 pr_err("Failed to create tun sysfs files\n"); 1697 } 1698 1699 netif_carrier_on(tun->dev); 1700 1701 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1702 1703 if (ifr->ifr_flags & IFF_NO_PI) 1704 tun->flags |= TUN_NO_PI; 1705 else 1706 tun->flags &= ~TUN_NO_PI; 1707 1708 /* This flag has no real effect. We track the value for backwards 1709 * compatibility. 1710 */ 1711 if (ifr->ifr_flags & IFF_ONE_QUEUE) 1712 tun->flags |= TUN_ONE_QUEUE; 1713 else 1714 tun->flags &= ~TUN_ONE_QUEUE; 1715 1716 if (ifr->ifr_flags & IFF_VNET_HDR) 1717 tun->flags |= TUN_VNET_HDR; 1718 else 1719 tun->flags &= ~TUN_VNET_HDR; 1720 1721 if (ifr->ifr_flags & IFF_MULTI_QUEUE) 1722 tun->flags |= TUN_TAP_MQ; 1723 else 1724 tun->flags &= ~TUN_TAP_MQ; 1725 1726 /* Make sure persistent devices do not get stuck in 1727 * xoff state. 1728 */ 1729 if (netif_running(tun->dev)) 1730 netif_tx_wake_all_queues(tun->dev); 1731 1732 strcpy(ifr->ifr_name, tun->dev->name); 1733 return 0; 1734 1735 err_detach: 1736 tun_detach_all(dev); 1737 err_free_flow: 1738 tun_flow_uninit(tun); 1739 security_tun_dev_free_security(tun->security); 1740 err_free_dev: 1741 free_netdev(dev); 1742 return err; 1743 } 1744 1745 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1746 struct ifreq *ifr) 1747 { 1748 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1749 1750 strcpy(ifr->ifr_name, tun->dev->name); 1751 1752 ifr->ifr_flags = tun_flags(tun); 1753 1754 } 1755 1756 /* This is like a cut-down ethtool ops, except done via tun fd so no 1757 * privs required. */ 1758 static int set_offload(struct tun_struct *tun, unsigned long arg) 1759 { 1760 netdev_features_t features = 0; 1761 1762 if (arg & TUN_F_CSUM) { 1763 features |= NETIF_F_HW_CSUM; 1764 arg &= ~TUN_F_CSUM; 1765 1766 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1767 if (arg & TUN_F_TSO_ECN) { 1768 features |= NETIF_F_TSO_ECN; 1769 arg &= ~TUN_F_TSO_ECN; 1770 } 1771 if (arg & TUN_F_TSO4) 1772 features |= NETIF_F_TSO; 1773 if (arg & TUN_F_TSO6) 1774 features |= NETIF_F_TSO6; 1775 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1776 } 1777 } 1778 1779 /* This gives the user a way to test for new features in future by 1780 * trying to set them. */ 1781 if (arg) 1782 return -EINVAL; 1783 1784 tun->set_features = features; 1785 netdev_update_features(tun->dev); 1786 1787 return 0; 1788 } 1789 1790 static void tun_detach_filter(struct tun_struct *tun, int n) 1791 { 1792 int i; 1793 struct tun_file *tfile; 1794 1795 for (i = 0; i < n; i++) { 1796 tfile = rtnl_dereference(tun->tfiles[i]); 1797 sk_detach_filter(tfile->socket.sk); 1798 } 1799 1800 tun->filter_attached = false; 1801 } 1802 1803 static int tun_attach_filter(struct tun_struct *tun) 1804 { 1805 int i, ret = 0; 1806 struct tun_file *tfile; 1807 1808 for (i = 0; i < tun->numqueues; i++) { 1809 tfile = rtnl_dereference(tun->tfiles[i]); 1810 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1811 if (ret) { 1812 tun_detach_filter(tun, i); 1813 return ret; 1814 } 1815 } 1816 1817 tun->filter_attached = true; 1818 return ret; 1819 } 1820 1821 static void tun_set_sndbuf(struct tun_struct *tun) 1822 { 1823 struct tun_file *tfile; 1824 int i; 1825 1826 for (i = 0; i < tun->numqueues; i++) { 1827 tfile = rtnl_dereference(tun->tfiles[i]); 1828 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1829 } 1830 } 1831 1832 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1833 { 1834 struct tun_file *tfile = file->private_data; 1835 struct tun_struct *tun; 1836 int ret = 0; 1837 1838 rtnl_lock(); 1839 1840 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1841 tun = tfile->detached; 1842 if (!tun) { 1843 ret = -EINVAL; 1844 goto unlock; 1845 } 1846 ret = security_tun_dev_attach_queue(tun->security); 1847 if (ret < 0) 1848 goto unlock; 1849 ret = tun_attach(tun, file, false); 1850 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1851 tun = rtnl_dereference(tfile->tun); 1852 if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) 1853 ret = -EINVAL; 1854 else 1855 __tun_detach(tfile, false); 1856 } else 1857 ret = -EINVAL; 1858 1859 unlock: 1860 rtnl_unlock(); 1861 return ret; 1862 } 1863 1864 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1865 unsigned long arg, int ifreq_len) 1866 { 1867 struct tun_file *tfile = file->private_data; 1868 struct tun_struct *tun; 1869 void __user* argp = (void __user*)arg; 1870 struct ifreq ifr; 1871 kuid_t owner; 1872 kgid_t group; 1873 int sndbuf; 1874 int vnet_hdr_sz; 1875 unsigned int ifindex; 1876 int ret; 1877 1878 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1879 if (copy_from_user(&ifr, argp, ifreq_len)) 1880 return -EFAULT; 1881 } else { 1882 memset(&ifr, 0, sizeof(ifr)); 1883 } 1884 if (cmd == TUNGETFEATURES) { 1885 /* Currently this just means: "what IFF flags are valid?". 1886 * This is needed because we never checked for invalid flags on 1887 * TUNSETIFF. */ 1888 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | 1889 IFF_VNET_HDR | IFF_MULTI_QUEUE, 1890 (unsigned int __user*)argp); 1891 } else if (cmd == TUNSETQUEUE) 1892 return tun_set_queue(file, &ifr); 1893 1894 ret = 0; 1895 rtnl_lock(); 1896 1897 tun = __tun_get(tfile); 1898 if (cmd == TUNSETIFF && !tun) { 1899 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1900 1901 ret = tun_set_iff(tfile->net, file, &ifr); 1902 1903 if (ret) 1904 goto unlock; 1905 1906 if (copy_to_user(argp, &ifr, ifreq_len)) 1907 ret = -EFAULT; 1908 goto unlock; 1909 } 1910 if (cmd == TUNSETIFINDEX) { 1911 ret = -EPERM; 1912 if (tun) 1913 goto unlock; 1914 1915 ret = -EFAULT; 1916 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1917 goto unlock; 1918 1919 ret = 0; 1920 tfile->ifindex = ifindex; 1921 goto unlock; 1922 } 1923 1924 ret = -EBADFD; 1925 if (!tun) 1926 goto unlock; 1927 1928 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1929 1930 ret = 0; 1931 switch (cmd) { 1932 case TUNGETIFF: 1933 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1934 1935 if (tfile->detached) 1936 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1937 if (!tfile->socket.sk->sk_filter) 1938 ifr.ifr_flags |= IFF_NOFILTER; 1939 1940 if (copy_to_user(argp, &ifr, ifreq_len)) 1941 ret = -EFAULT; 1942 break; 1943 1944 case TUNSETNOCSUM: 1945 /* Disable/Enable checksum */ 1946 1947 /* [unimplemented] */ 1948 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1949 arg ? "disabled" : "enabled"); 1950 break; 1951 1952 case TUNSETPERSIST: 1953 /* Disable/Enable persist mode. Keep an extra reference to the 1954 * module to prevent the module being unprobed. 1955 */ 1956 if (arg && !(tun->flags & TUN_PERSIST)) { 1957 tun->flags |= TUN_PERSIST; 1958 __module_get(THIS_MODULE); 1959 } 1960 if (!arg && (tun->flags & TUN_PERSIST)) { 1961 tun->flags &= ~TUN_PERSIST; 1962 module_put(THIS_MODULE); 1963 } 1964 1965 tun_debug(KERN_INFO, tun, "persist %s\n", 1966 arg ? "enabled" : "disabled"); 1967 break; 1968 1969 case TUNSETOWNER: 1970 /* Set owner of the device */ 1971 owner = make_kuid(current_user_ns(), arg); 1972 if (!uid_valid(owner)) { 1973 ret = -EINVAL; 1974 break; 1975 } 1976 tun->owner = owner; 1977 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1978 from_kuid(&init_user_ns, tun->owner)); 1979 break; 1980 1981 case TUNSETGROUP: 1982 /* Set group of the device */ 1983 group = make_kgid(current_user_ns(), arg); 1984 if (!gid_valid(group)) { 1985 ret = -EINVAL; 1986 break; 1987 } 1988 tun->group = group; 1989 tun_debug(KERN_INFO, tun, "group set to %u\n", 1990 from_kgid(&init_user_ns, tun->group)); 1991 break; 1992 1993 case TUNSETLINK: 1994 /* Only allow setting the type when the interface is down */ 1995 if (tun->dev->flags & IFF_UP) { 1996 tun_debug(KERN_INFO, tun, 1997 "Linktype set failed because interface is up\n"); 1998 ret = -EBUSY; 1999 } else { 2000 tun->dev->type = (int) arg; 2001 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 2002 tun->dev->type); 2003 ret = 0; 2004 } 2005 break; 2006 2007 #ifdef TUN_DEBUG 2008 case TUNSETDEBUG: 2009 tun->debug = arg; 2010 break; 2011 #endif 2012 case TUNSETOFFLOAD: 2013 ret = set_offload(tun, arg); 2014 break; 2015 2016 case TUNSETTXFILTER: 2017 /* Can be set only for TAPs */ 2018 ret = -EINVAL; 2019 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2020 break; 2021 ret = update_filter(&tun->txflt, (void __user *)arg); 2022 break; 2023 2024 case SIOCGIFHWADDR: 2025 /* Get hw address */ 2026 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 2027 ifr.ifr_hwaddr.sa_family = tun->dev->type; 2028 if (copy_to_user(argp, &ifr, ifreq_len)) 2029 ret = -EFAULT; 2030 break; 2031 2032 case SIOCSIFHWADDR: 2033 /* Set hw address */ 2034 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 2035 ifr.ifr_hwaddr.sa_data); 2036 2037 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2038 break; 2039 2040 case TUNGETSNDBUF: 2041 sndbuf = tfile->socket.sk->sk_sndbuf; 2042 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2043 ret = -EFAULT; 2044 break; 2045 2046 case TUNSETSNDBUF: 2047 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2048 ret = -EFAULT; 2049 break; 2050 } 2051 2052 tun->sndbuf = sndbuf; 2053 tun_set_sndbuf(tun); 2054 break; 2055 2056 case TUNGETVNETHDRSZ: 2057 vnet_hdr_sz = tun->vnet_hdr_sz; 2058 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2059 ret = -EFAULT; 2060 break; 2061 2062 case TUNSETVNETHDRSZ: 2063 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2064 ret = -EFAULT; 2065 break; 2066 } 2067 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2068 ret = -EINVAL; 2069 break; 2070 } 2071 2072 tun->vnet_hdr_sz = vnet_hdr_sz; 2073 break; 2074 2075 case TUNATTACHFILTER: 2076 /* Can be set only for TAPs */ 2077 ret = -EINVAL; 2078 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2079 break; 2080 ret = -EFAULT; 2081 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2082 break; 2083 2084 ret = tun_attach_filter(tun); 2085 break; 2086 2087 case TUNDETACHFILTER: 2088 /* Can be set only for TAPs */ 2089 ret = -EINVAL; 2090 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2091 break; 2092 ret = 0; 2093 tun_detach_filter(tun, tun->numqueues); 2094 break; 2095 2096 case TUNGETFILTER: 2097 ret = -EINVAL; 2098 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2099 break; 2100 ret = -EFAULT; 2101 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2102 break; 2103 ret = 0; 2104 break; 2105 2106 default: 2107 ret = -EINVAL; 2108 break; 2109 } 2110 2111 unlock: 2112 rtnl_unlock(); 2113 if (tun) 2114 tun_put(tun); 2115 return ret; 2116 } 2117 2118 static long tun_chr_ioctl(struct file *file, 2119 unsigned int cmd, unsigned long arg) 2120 { 2121 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2122 } 2123 2124 #ifdef CONFIG_COMPAT 2125 static long tun_chr_compat_ioctl(struct file *file, 2126 unsigned int cmd, unsigned long arg) 2127 { 2128 switch (cmd) { 2129 case TUNSETIFF: 2130 case TUNGETIFF: 2131 case TUNSETTXFILTER: 2132 case TUNGETSNDBUF: 2133 case TUNSETSNDBUF: 2134 case SIOCGIFHWADDR: 2135 case SIOCSIFHWADDR: 2136 arg = (unsigned long)compat_ptr(arg); 2137 break; 2138 default: 2139 arg = (compat_ulong_t)arg; 2140 break; 2141 } 2142 2143 /* 2144 * compat_ifreq is shorter than ifreq, so we must not access beyond 2145 * the end of that structure. All fields that are used in this 2146 * driver are compatible though, we don't need to convert the 2147 * contents. 2148 */ 2149 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2150 } 2151 #endif /* CONFIG_COMPAT */ 2152 2153 static int tun_chr_fasync(int fd, struct file *file, int on) 2154 { 2155 struct tun_file *tfile = file->private_data; 2156 int ret; 2157 2158 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2159 goto out; 2160 2161 if (on) { 2162 __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2163 tfile->flags |= TUN_FASYNC; 2164 } else 2165 tfile->flags &= ~TUN_FASYNC; 2166 ret = 0; 2167 out: 2168 return ret; 2169 } 2170 2171 static int tun_chr_open(struct inode *inode, struct file * file) 2172 { 2173 struct tun_file *tfile; 2174 2175 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2176 2177 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2178 &tun_proto); 2179 if (!tfile) 2180 return -ENOMEM; 2181 RCU_INIT_POINTER(tfile->tun, NULL); 2182 tfile->net = get_net(current->nsproxy->net_ns); 2183 tfile->flags = 0; 2184 tfile->ifindex = 0; 2185 2186 init_waitqueue_head(&tfile->wq.wait); 2187 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq); 2188 2189 tfile->socket.file = file; 2190 tfile->socket.ops = &tun_socket_ops; 2191 2192 sock_init_data(&tfile->socket, &tfile->sk); 2193 sk_change_net(&tfile->sk, tfile->net); 2194 2195 tfile->sk.sk_write_space = tun_sock_write_space; 2196 tfile->sk.sk_sndbuf = INT_MAX; 2197 2198 file->private_data = tfile; 2199 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2200 INIT_LIST_HEAD(&tfile->next); 2201 2202 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2203 2204 return 0; 2205 } 2206 2207 static int tun_chr_close(struct inode *inode, struct file *file) 2208 { 2209 struct tun_file *tfile = file->private_data; 2210 struct net *net = tfile->net; 2211 2212 tun_detach(tfile, true); 2213 put_net(net); 2214 2215 return 0; 2216 } 2217 2218 #ifdef CONFIG_PROC_FS 2219 static int tun_chr_show_fdinfo(struct seq_file *m, struct file *f) 2220 { 2221 struct tun_struct *tun; 2222 struct ifreq ifr; 2223 2224 memset(&ifr, 0, sizeof(ifr)); 2225 2226 rtnl_lock(); 2227 tun = tun_get(f); 2228 if (tun) 2229 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 2230 rtnl_unlock(); 2231 2232 if (tun) 2233 tun_put(tun); 2234 2235 return seq_printf(m, "iff:\t%s\n", ifr.ifr_name); 2236 } 2237 #endif 2238 2239 static const struct file_operations tun_fops = { 2240 .owner = THIS_MODULE, 2241 .llseek = no_llseek, 2242 .read = do_sync_read, 2243 .aio_read = tun_chr_aio_read, 2244 .write = do_sync_write, 2245 .aio_write = tun_chr_aio_write, 2246 .poll = tun_chr_poll, 2247 .unlocked_ioctl = tun_chr_ioctl, 2248 #ifdef CONFIG_COMPAT 2249 .compat_ioctl = tun_chr_compat_ioctl, 2250 #endif 2251 .open = tun_chr_open, 2252 .release = tun_chr_close, 2253 .fasync = tun_chr_fasync, 2254 #ifdef CONFIG_PROC_FS 2255 .show_fdinfo = tun_chr_show_fdinfo, 2256 #endif 2257 }; 2258 2259 static struct miscdevice tun_miscdev = { 2260 .minor = TUN_MINOR, 2261 .name = "tun", 2262 .nodename = "net/tun", 2263 .fops = &tun_fops, 2264 }; 2265 2266 /* ethtool interface */ 2267 2268 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2269 { 2270 cmd->supported = 0; 2271 cmd->advertising = 0; 2272 ethtool_cmd_speed_set(cmd, SPEED_10); 2273 cmd->duplex = DUPLEX_FULL; 2274 cmd->port = PORT_TP; 2275 cmd->phy_address = 0; 2276 cmd->transceiver = XCVR_INTERNAL; 2277 cmd->autoneg = AUTONEG_DISABLE; 2278 cmd->maxtxpkt = 0; 2279 cmd->maxrxpkt = 0; 2280 return 0; 2281 } 2282 2283 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2284 { 2285 struct tun_struct *tun = netdev_priv(dev); 2286 2287 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2288 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2289 2290 switch (tun->flags & TUN_TYPE_MASK) { 2291 case TUN_TUN_DEV: 2292 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2293 break; 2294 case TUN_TAP_DEV: 2295 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2296 break; 2297 } 2298 } 2299 2300 static u32 tun_get_msglevel(struct net_device *dev) 2301 { 2302 #ifdef TUN_DEBUG 2303 struct tun_struct *tun = netdev_priv(dev); 2304 return tun->debug; 2305 #else 2306 return -EOPNOTSUPP; 2307 #endif 2308 } 2309 2310 static void tun_set_msglevel(struct net_device *dev, u32 value) 2311 { 2312 #ifdef TUN_DEBUG 2313 struct tun_struct *tun = netdev_priv(dev); 2314 tun->debug = value; 2315 #endif 2316 } 2317 2318 static const struct ethtool_ops tun_ethtool_ops = { 2319 .get_settings = tun_get_settings, 2320 .get_drvinfo = tun_get_drvinfo, 2321 .get_msglevel = tun_get_msglevel, 2322 .set_msglevel = tun_set_msglevel, 2323 .get_link = ethtool_op_get_link, 2324 .get_ts_info = ethtool_op_get_ts_info, 2325 }; 2326 2327 2328 static int __init tun_init(void) 2329 { 2330 int ret = 0; 2331 2332 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2333 pr_info("%s\n", DRV_COPYRIGHT); 2334 2335 ret = rtnl_link_register(&tun_link_ops); 2336 if (ret) { 2337 pr_err("Can't register link_ops\n"); 2338 goto err_linkops; 2339 } 2340 2341 ret = misc_register(&tun_miscdev); 2342 if (ret) { 2343 pr_err("Can't register misc device %d\n", TUN_MINOR); 2344 goto err_misc; 2345 } 2346 return 0; 2347 err_misc: 2348 rtnl_link_unregister(&tun_link_ops); 2349 err_linkops: 2350 return ret; 2351 } 2352 2353 static void tun_cleanup(void) 2354 { 2355 misc_deregister(&tun_miscdev); 2356 rtnl_link_unregister(&tun_link_ops); 2357 } 2358 2359 /* Get an underlying socket object from tun file. Returns error unless file is 2360 * attached to a device. The returned object works like a packet socket, it 2361 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2362 * holding a reference to the file for as long as the socket is in use. */ 2363 struct socket *tun_get_socket(struct file *file) 2364 { 2365 struct tun_file *tfile; 2366 if (file->f_op != &tun_fops) 2367 return ERR_PTR(-EINVAL); 2368 tfile = file->private_data; 2369 if (!tfile) 2370 return ERR_PTR(-EBADFD); 2371 return &tfile->socket; 2372 } 2373 EXPORT_SYMBOL_GPL(tun_get_socket); 2374 2375 module_init(tun_init); 2376 module_exit(tun_cleanup); 2377 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2378 MODULE_AUTHOR(DRV_COPYRIGHT); 2379 MODULE_LICENSE("GPL"); 2380 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2381 MODULE_ALIAS("devname:net/tun"); 2382