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/crc32.h> 64 #include <linux/nsproxy.h> 65 #include <linux/virtio_net.h> 66 #include <linux/rcupdate.h> 67 #include <net/net_namespace.h> 68 #include <net/netns/generic.h> 69 #include <net/rtnetlink.h> 70 #include <net/sock.h> 71 72 #include <asm/uaccess.h> 73 74 /* Uncomment to enable debugging */ 75 /* #define TUN_DEBUG 1 */ 76 77 #ifdef TUN_DEBUG 78 static int debug; 79 80 #define tun_debug(level, tun, fmt, args...) \ 81 do { \ 82 if (tun->debug) \ 83 netdev_printk(level, tun->dev, fmt, ##args); \ 84 } while (0) 85 #define DBG1(level, fmt, args...) \ 86 do { \ 87 if (debug == 2) \ 88 printk(level fmt, ##args); \ 89 } while (0) 90 #else 91 #define tun_debug(level, tun, fmt, args...) \ 92 do { \ 93 if (0) \ 94 netdev_printk(level, tun->dev, fmt, ##args); \ 95 } while (0) 96 #define DBG1(level, fmt, args...) \ 97 do { \ 98 if (0) \ 99 printk(level fmt, ##args); \ 100 } while (0) 101 #endif 102 103 #define GOODCOPY_LEN 128 104 105 #define FLT_EXACT_COUNT 8 106 struct tap_filter { 107 unsigned int count; /* Number of addrs. Zero means disabled */ 108 u32 mask[2]; /* Mask of the hashed addrs */ 109 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 110 }; 111 112 /* 1024 is probably a high enough limit: modern hypervisors seem to support on 113 * the order of 100-200 CPUs so this leaves us some breathing space if we want 114 * to match a queue per guest CPU. 115 */ 116 #define MAX_TAP_QUEUES 1024 117 118 #define TUN_FLOW_EXPIRE (3 * HZ) 119 120 /* A tun_file connects an open character device to a tuntap netdevice. It 121 * also contains all socket related strctures (except sock_fprog and tap_filter) 122 * to serve as one transmit queue for tuntap device. The sock_fprog and 123 * tap_filter were kept in tun_struct since they were used for filtering for the 124 * netdevice not for a specific queue (at least I didn't see the requirement for 125 * this). 126 * 127 * RCU usage: 128 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 129 * other can only be read while rcu_read_lock or rtnl_lock is held. 130 */ 131 struct tun_file { 132 struct sock sk; 133 struct socket socket; 134 struct socket_wq wq; 135 struct tun_struct __rcu *tun; 136 struct net *net; 137 struct fasync_struct *fasync; 138 /* only used for fasnyc */ 139 unsigned int flags; 140 u16 queue_index; 141 struct list_head next; 142 struct tun_struct *detached; 143 }; 144 145 struct tun_flow_entry { 146 struct hlist_node hash_link; 147 struct rcu_head rcu; 148 struct tun_struct *tun; 149 150 u32 rxhash; 151 int queue_index; 152 unsigned long updated; 153 }; 154 155 #define TUN_NUM_FLOW_ENTRIES 1024 156 157 /* Since the socket were moved to tun_file, to preserve the behavior of persist 158 * device, socket filter, sndbuf and vnet header size were restore when the 159 * file were attached to a persist device. 160 */ 161 struct tun_struct { 162 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 163 unsigned int numqueues; 164 unsigned int flags; 165 kuid_t owner; 166 kgid_t group; 167 168 struct net_device *dev; 169 netdev_features_t set_features; 170 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 171 NETIF_F_TSO6|NETIF_F_UFO) 172 173 int vnet_hdr_sz; 174 int sndbuf; 175 struct tap_filter txflt; 176 struct sock_fprog fprog; 177 /* protected by rtnl lock */ 178 bool filter_attached; 179 #ifdef TUN_DEBUG 180 int debug; 181 #endif 182 spinlock_t lock; 183 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 184 struct timer_list flow_gc_timer; 185 unsigned long ageing_time; 186 unsigned int numdisabled; 187 struct list_head disabled; 188 }; 189 190 static inline u32 tun_hashfn(u32 rxhash) 191 { 192 return rxhash & 0x3ff; 193 } 194 195 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 196 { 197 struct tun_flow_entry *e; 198 struct hlist_node *n; 199 200 hlist_for_each_entry_rcu(e, n, head, hash_link) { 201 if (e->rxhash == rxhash) 202 return e; 203 } 204 return NULL; 205 } 206 207 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 208 struct hlist_head *head, 209 u32 rxhash, u16 queue_index) 210 { 211 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 212 213 if (e) { 214 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 215 rxhash, queue_index); 216 e->updated = jiffies; 217 e->rxhash = rxhash; 218 e->queue_index = queue_index; 219 e->tun = tun; 220 hlist_add_head_rcu(&e->hash_link, head); 221 } 222 return e; 223 } 224 225 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 226 { 227 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 228 e->rxhash, e->queue_index); 229 hlist_del_rcu(&e->hash_link); 230 kfree_rcu(e, rcu); 231 } 232 233 static void tun_flow_flush(struct tun_struct *tun) 234 { 235 int i; 236 237 spin_lock_bh(&tun->lock); 238 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 239 struct tun_flow_entry *e; 240 struct hlist_node *h, *n; 241 242 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link) 243 tun_flow_delete(tun, e); 244 } 245 spin_unlock_bh(&tun->lock); 246 } 247 248 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 249 { 250 int i; 251 252 spin_lock_bh(&tun->lock); 253 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 254 struct tun_flow_entry *e; 255 struct hlist_node *h, *n; 256 257 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link) { 258 if (e->queue_index == queue_index) 259 tun_flow_delete(tun, e); 260 } 261 } 262 spin_unlock_bh(&tun->lock); 263 } 264 265 static void tun_flow_cleanup(unsigned long data) 266 { 267 struct tun_struct *tun = (struct tun_struct *)data; 268 unsigned long delay = tun->ageing_time; 269 unsigned long next_timer = jiffies + delay; 270 unsigned long count = 0; 271 int i; 272 273 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 274 275 spin_lock_bh(&tun->lock); 276 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 277 struct tun_flow_entry *e; 278 struct hlist_node *h, *n; 279 280 hlist_for_each_entry_safe(e, h, n, &tun->flows[i], hash_link) { 281 unsigned long this_timer; 282 count++; 283 this_timer = e->updated + delay; 284 if (time_before_eq(this_timer, jiffies)) 285 tun_flow_delete(tun, e); 286 else if (time_before(this_timer, next_timer)) 287 next_timer = this_timer; 288 } 289 } 290 291 if (count) 292 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 293 spin_unlock_bh(&tun->lock); 294 } 295 296 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 297 u16 queue_index) 298 { 299 struct hlist_head *head; 300 struct tun_flow_entry *e; 301 unsigned long delay = tun->ageing_time; 302 303 if (!rxhash) 304 return; 305 else 306 head = &tun->flows[tun_hashfn(rxhash)]; 307 308 rcu_read_lock(); 309 310 if (tun->numqueues == 1) 311 goto unlock; 312 313 e = tun_flow_find(head, rxhash); 314 if (likely(e)) { 315 /* TODO: keep queueing to old queue until it's empty? */ 316 e->queue_index = queue_index; 317 e->updated = jiffies; 318 } else { 319 spin_lock_bh(&tun->lock); 320 if (!tun_flow_find(head, rxhash)) 321 tun_flow_create(tun, head, rxhash, queue_index); 322 323 if (!timer_pending(&tun->flow_gc_timer)) 324 mod_timer(&tun->flow_gc_timer, 325 round_jiffies_up(jiffies + delay)); 326 spin_unlock_bh(&tun->lock); 327 } 328 329 unlock: 330 rcu_read_unlock(); 331 } 332 333 /* We try to identify a flow through its rxhash first. The reason that 334 * we do not check rxq no. is becuase some cards(e.g 82599), chooses 335 * the rxq based on the txq where the last packet of the flow comes. As 336 * the userspace application move between processors, we may get a 337 * different rxq no. here. If we could not get rxhash, then we would 338 * hope the rxq no. may help here. 339 */ 340 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb) 341 { 342 struct tun_struct *tun = netdev_priv(dev); 343 struct tun_flow_entry *e; 344 u32 txq = 0; 345 u32 numqueues = 0; 346 347 rcu_read_lock(); 348 numqueues = tun->numqueues; 349 350 txq = skb_get_rxhash(skb); 351 if (txq) { 352 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 353 if (e) 354 txq = e->queue_index; 355 else 356 /* use multiply and shift instead of expensive divide */ 357 txq = ((u64)txq * numqueues) >> 32; 358 } else if (likely(skb_rx_queue_recorded(skb))) { 359 txq = skb_get_rx_queue(skb); 360 while (unlikely(txq >= numqueues)) 361 txq -= numqueues; 362 } 363 364 rcu_read_unlock(); 365 return txq; 366 } 367 368 static inline bool tun_not_capable(struct tun_struct *tun) 369 { 370 const struct cred *cred = current_cred(); 371 struct net *net = dev_net(tun->dev); 372 373 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 374 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 375 !ns_capable(net->user_ns, CAP_NET_ADMIN); 376 } 377 378 static void tun_set_real_num_queues(struct tun_struct *tun) 379 { 380 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 381 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 382 } 383 384 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 385 { 386 tfile->detached = tun; 387 list_add_tail(&tfile->next, &tun->disabled); 388 ++tun->numdisabled; 389 } 390 391 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 392 { 393 struct tun_struct *tun = tfile->detached; 394 395 tfile->detached = NULL; 396 list_del_init(&tfile->next); 397 --tun->numdisabled; 398 return tun; 399 } 400 401 static void __tun_detach(struct tun_file *tfile, bool clean) 402 { 403 struct tun_file *ntfile; 404 struct tun_struct *tun; 405 struct net_device *dev; 406 407 tun = rtnl_dereference(tfile->tun); 408 409 if (tun) { 410 u16 index = tfile->queue_index; 411 BUG_ON(index >= tun->numqueues); 412 dev = tun->dev; 413 414 rcu_assign_pointer(tun->tfiles[index], 415 tun->tfiles[tun->numqueues - 1]); 416 rcu_assign_pointer(tfile->tun, NULL); 417 ntfile = rtnl_dereference(tun->tfiles[index]); 418 ntfile->queue_index = index; 419 420 --tun->numqueues; 421 if (clean) 422 sock_put(&tfile->sk); 423 else 424 tun_disable_queue(tun, tfile); 425 426 synchronize_net(); 427 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 428 /* Drop read queue */ 429 skb_queue_purge(&tfile->sk.sk_receive_queue); 430 tun_set_real_num_queues(tun); 431 } else if (tfile->detached && clean) { 432 tun = tun_enable_queue(tfile); 433 sock_put(&tfile->sk); 434 } 435 436 if (clean) { 437 if (tun && tun->numqueues == 0 && tun->numdisabled == 0 && 438 !(tun->flags & TUN_PERSIST)) 439 if (tun->dev->reg_state == NETREG_REGISTERED) 440 unregister_netdevice(tun->dev); 441 442 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 443 &tfile->socket.flags)); 444 sk_release_kernel(&tfile->sk); 445 } 446 } 447 448 static void tun_detach(struct tun_file *tfile, bool clean) 449 { 450 rtnl_lock(); 451 __tun_detach(tfile, clean); 452 rtnl_unlock(); 453 } 454 455 static void tun_detach_all(struct net_device *dev) 456 { 457 struct tun_struct *tun = netdev_priv(dev); 458 struct tun_file *tfile, *tmp; 459 int i, n = tun->numqueues; 460 461 for (i = 0; i < n; i++) { 462 tfile = rtnl_dereference(tun->tfiles[i]); 463 BUG_ON(!tfile); 464 wake_up_all(&tfile->wq.wait); 465 rcu_assign_pointer(tfile->tun, NULL); 466 --tun->numqueues; 467 } 468 BUG_ON(tun->numqueues != 0); 469 470 synchronize_net(); 471 for (i = 0; i < n; i++) { 472 tfile = rtnl_dereference(tun->tfiles[i]); 473 /* Drop read queue */ 474 skb_queue_purge(&tfile->sk.sk_receive_queue); 475 sock_put(&tfile->sk); 476 } 477 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 478 tun_enable_queue(tfile); 479 skb_queue_purge(&tfile->sk.sk_receive_queue); 480 sock_put(&tfile->sk); 481 } 482 BUG_ON(tun->numdisabled != 0); 483 484 if (tun->flags & TUN_PERSIST) 485 module_put(THIS_MODULE); 486 } 487 488 static int tun_attach(struct tun_struct *tun, struct file *file) 489 { 490 struct tun_file *tfile = file->private_data; 491 int err; 492 493 err = -EINVAL; 494 if (rtnl_dereference(tfile->tun)) 495 goto out; 496 497 err = -EBUSY; 498 if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1) 499 goto out; 500 501 err = -E2BIG; 502 if (!tfile->detached && 503 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 504 goto out; 505 506 err = 0; 507 508 /* Re-attach the filter to presist device */ 509 if (tun->filter_attached == true) { 510 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 511 if (!err) 512 goto out; 513 } 514 tfile->queue_index = tun->numqueues; 515 rcu_assign_pointer(tfile->tun, tun); 516 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 517 tun->numqueues++; 518 519 if (tfile->detached) 520 tun_enable_queue(tfile); 521 else 522 sock_hold(&tfile->sk); 523 524 tun_set_real_num_queues(tun); 525 526 /* device is allowed to go away first, so no need to hold extra 527 * refcnt. 528 */ 529 530 out: 531 return err; 532 } 533 534 static struct tun_struct *__tun_get(struct tun_file *tfile) 535 { 536 struct tun_struct *tun; 537 538 rcu_read_lock(); 539 tun = rcu_dereference(tfile->tun); 540 if (tun) 541 dev_hold(tun->dev); 542 rcu_read_unlock(); 543 544 return tun; 545 } 546 547 static struct tun_struct *tun_get(struct file *file) 548 { 549 return __tun_get(file->private_data); 550 } 551 552 static void tun_put(struct tun_struct *tun) 553 { 554 dev_put(tun->dev); 555 } 556 557 /* TAP filtering */ 558 static void addr_hash_set(u32 *mask, const u8 *addr) 559 { 560 int n = ether_crc(ETH_ALEN, addr) >> 26; 561 mask[n >> 5] |= (1 << (n & 31)); 562 } 563 564 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 565 { 566 int n = ether_crc(ETH_ALEN, addr) >> 26; 567 return mask[n >> 5] & (1 << (n & 31)); 568 } 569 570 static int update_filter(struct tap_filter *filter, void __user *arg) 571 { 572 struct { u8 u[ETH_ALEN]; } *addr; 573 struct tun_filter uf; 574 int err, alen, n, nexact; 575 576 if (copy_from_user(&uf, arg, sizeof(uf))) 577 return -EFAULT; 578 579 if (!uf.count) { 580 /* Disabled */ 581 filter->count = 0; 582 return 0; 583 } 584 585 alen = ETH_ALEN * uf.count; 586 addr = kmalloc(alen, GFP_KERNEL); 587 if (!addr) 588 return -ENOMEM; 589 590 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 591 err = -EFAULT; 592 goto done; 593 } 594 595 /* The filter is updated without holding any locks. Which is 596 * perfectly safe. We disable it first and in the worst 597 * case we'll accept a few undesired packets. */ 598 filter->count = 0; 599 wmb(); 600 601 /* Use first set of addresses as an exact filter */ 602 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 603 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 604 605 nexact = n; 606 607 /* Remaining multicast addresses are hashed, 608 * unicast will leave the filter disabled. */ 609 memset(filter->mask, 0, sizeof(filter->mask)); 610 for (; n < uf.count; n++) { 611 if (!is_multicast_ether_addr(addr[n].u)) { 612 err = 0; /* no filter */ 613 goto done; 614 } 615 addr_hash_set(filter->mask, addr[n].u); 616 } 617 618 /* For ALLMULTI just set the mask to all ones. 619 * This overrides the mask populated above. */ 620 if ((uf.flags & TUN_FLT_ALLMULTI)) 621 memset(filter->mask, ~0, sizeof(filter->mask)); 622 623 /* Now enable the filter */ 624 wmb(); 625 filter->count = nexact; 626 627 /* Return the number of exact filters */ 628 err = nexact; 629 630 done: 631 kfree(addr); 632 return err; 633 } 634 635 /* Returns: 0 - drop, !=0 - accept */ 636 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 637 { 638 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 639 * at this point. */ 640 struct ethhdr *eh = (struct ethhdr *) skb->data; 641 int i; 642 643 /* Exact match */ 644 for (i = 0; i < filter->count; i++) 645 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 646 return 1; 647 648 /* Inexact match (multicast only) */ 649 if (is_multicast_ether_addr(eh->h_dest)) 650 return addr_hash_test(filter->mask, eh->h_dest); 651 652 return 0; 653 } 654 655 /* 656 * Checks whether the packet is accepted or not. 657 * Returns: 0 - drop, !=0 - accept 658 */ 659 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 660 { 661 if (!filter->count) 662 return 1; 663 664 return run_filter(filter, skb); 665 } 666 667 /* Network device part of the driver */ 668 669 static const struct ethtool_ops tun_ethtool_ops; 670 671 /* Net device detach from fd. */ 672 static void tun_net_uninit(struct net_device *dev) 673 { 674 tun_detach_all(dev); 675 } 676 677 /* Net device open. */ 678 static int tun_net_open(struct net_device *dev) 679 { 680 netif_tx_start_all_queues(dev); 681 return 0; 682 } 683 684 /* Net device close. */ 685 static int tun_net_close(struct net_device *dev) 686 { 687 netif_tx_stop_all_queues(dev); 688 return 0; 689 } 690 691 /* Net device start xmit */ 692 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 693 { 694 struct tun_struct *tun = netdev_priv(dev); 695 int txq = skb->queue_mapping; 696 struct tun_file *tfile; 697 698 rcu_read_lock(); 699 tfile = rcu_dereference(tun->tfiles[txq]); 700 701 /* Drop packet if interface is not attached */ 702 if (txq >= tun->numqueues) 703 goto drop; 704 705 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 706 707 BUG_ON(!tfile); 708 709 /* Drop if the filter does not like it. 710 * This is a noop if the filter is disabled. 711 * Filter can be enabled only for the TAP devices. */ 712 if (!check_filter(&tun->txflt, skb)) 713 goto drop; 714 715 if (tfile->socket.sk->sk_filter && 716 sk_filter(tfile->socket.sk, skb)) 717 goto drop; 718 719 /* Limit the number of packets queued by dividing txq length with the 720 * number of queues. 721 */ 722 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) 723 >= dev->tx_queue_len / tun->numqueues) 724 goto drop; 725 726 /* Orphan the skb - required as we might hang on to it 727 * for indefinite time. */ 728 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 729 goto drop; 730 skb_orphan(skb); 731 732 /* Enqueue packet */ 733 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 734 735 /* Notify and wake up reader process */ 736 if (tfile->flags & TUN_FASYNC) 737 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 738 wake_up_interruptible_poll(&tfile->wq.wait, POLLIN | 739 POLLRDNORM | POLLRDBAND); 740 741 rcu_read_unlock(); 742 return NETDEV_TX_OK; 743 744 drop: 745 dev->stats.tx_dropped++; 746 skb_tx_error(skb); 747 kfree_skb(skb); 748 rcu_read_unlock(); 749 return NETDEV_TX_OK; 750 } 751 752 static void tun_net_mclist(struct net_device *dev) 753 { 754 /* 755 * This callback is supposed to deal with mc filter in 756 * _rx_ path and has nothing to do with the _tx_ path. 757 * In rx path we always accept everything userspace gives us. 758 */ 759 } 760 761 #define MIN_MTU 68 762 #define MAX_MTU 65535 763 764 static int 765 tun_net_change_mtu(struct net_device *dev, int new_mtu) 766 { 767 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 768 return -EINVAL; 769 dev->mtu = new_mtu; 770 return 0; 771 } 772 773 static netdev_features_t tun_net_fix_features(struct net_device *dev, 774 netdev_features_t features) 775 { 776 struct tun_struct *tun = netdev_priv(dev); 777 778 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 779 } 780 #ifdef CONFIG_NET_POLL_CONTROLLER 781 static void tun_poll_controller(struct net_device *dev) 782 { 783 /* 784 * Tun only receives frames when: 785 * 1) the char device endpoint gets data from user space 786 * 2) the tun socket gets a sendmsg call from user space 787 * Since both of those are syncronous operations, we are guaranteed 788 * never to have pending data when we poll for it 789 * so theres nothing to do here but return. 790 * We need this though so netpoll recognizes us as an interface that 791 * supports polling, which enables bridge devices in virt setups to 792 * still use netconsole 793 */ 794 return; 795 } 796 #endif 797 static const struct net_device_ops tun_netdev_ops = { 798 .ndo_uninit = tun_net_uninit, 799 .ndo_open = tun_net_open, 800 .ndo_stop = tun_net_close, 801 .ndo_start_xmit = tun_net_xmit, 802 .ndo_change_mtu = tun_net_change_mtu, 803 .ndo_fix_features = tun_net_fix_features, 804 .ndo_select_queue = tun_select_queue, 805 #ifdef CONFIG_NET_POLL_CONTROLLER 806 .ndo_poll_controller = tun_poll_controller, 807 #endif 808 }; 809 810 static const struct net_device_ops tap_netdev_ops = { 811 .ndo_uninit = tun_net_uninit, 812 .ndo_open = tun_net_open, 813 .ndo_stop = tun_net_close, 814 .ndo_start_xmit = tun_net_xmit, 815 .ndo_change_mtu = tun_net_change_mtu, 816 .ndo_fix_features = tun_net_fix_features, 817 .ndo_set_rx_mode = tun_net_mclist, 818 .ndo_set_mac_address = eth_mac_addr, 819 .ndo_validate_addr = eth_validate_addr, 820 .ndo_select_queue = tun_select_queue, 821 #ifdef CONFIG_NET_POLL_CONTROLLER 822 .ndo_poll_controller = tun_poll_controller, 823 #endif 824 }; 825 826 static int tun_flow_init(struct tun_struct *tun) 827 { 828 int i; 829 830 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 831 INIT_HLIST_HEAD(&tun->flows[i]); 832 833 tun->ageing_time = TUN_FLOW_EXPIRE; 834 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 835 mod_timer(&tun->flow_gc_timer, 836 round_jiffies_up(jiffies + tun->ageing_time)); 837 838 return 0; 839 } 840 841 static void tun_flow_uninit(struct tun_struct *tun) 842 { 843 del_timer_sync(&tun->flow_gc_timer); 844 tun_flow_flush(tun); 845 } 846 847 /* Initialize net device. */ 848 static void tun_net_init(struct net_device *dev) 849 { 850 struct tun_struct *tun = netdev_priv(dev); 851 852 switch (tun->flags & TUN_TYPE_MASK) { 853 case TUN_TUN_DEV: 854 dev->netdev_ops = &tun_netdev_ops; 855 856 /* Point-to-Point TUN Device */ 857 dev->hard_header_len = 0; 858 dev->addr_len = 0; 859 dev->mtu = 1500; 860 861 /* Zero header length */ 862 dev->type = ARPHRD_NONE; 863 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 864 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 865 break; 866 867 case TUN_TAP_DEV: 868 dev->netdev_ops = &tap_netdev_ops; 869 /* Ethernet TAP Device */ 870 ether_setup(dev); 871 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 872 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 873 874 eth_hw_addr_random(dev); 875 876 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 877 break; 878 } 879 } 880 881 /* Character device part */ 882 883 /* Poll */ 884 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 885 { 886 struct tun_file *tfile = file->private_data; 887 struct tun_struct *tun = __tun_get(tfile); 888 struct sock *sk; 889 unsigned int mask = 0; 890 891 if (!tun) 892 return POLLERR; 893 894 sk = tfile->socket.sk; 895 896 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 897 898 poll_wait(file, &tfile->wq.wait, wait); 899 900 if (!skb_queue_empty(&sk->sk_receive_queue)) 901 mask |= POLLIN | POLLRDNORM; 902 903 if (sock_writeable(sk) || 904 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 905 sock_writeable(sk))) 906 mask |= POLLOUT | POLLWRNORM; 907 908 if (tun->dev->reg_state != NETREG_REGISTERED) 909 mask = POLLERR; 910 911 tun_put(tun); 912 return mask; 913 } 914 915 /* prepad is the amount to reserve at front. len is length after that. 916 * linear is a hint as to how much to copy (usually headers). */ 917 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 918 size_t prepad, size_t len, 919 size_t linear, int noblock) 920 { 921 struct sock *sk = tfile->socket.sk; 922 struct sk_buff *skb; 923 int err; 924 925 /* Under a page? Don't bother with paged skb. */ 926 if (prepad + len < PAGE_SIZE || !linear) 927 linear = len; 928 929 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 930 &err); 931 if (!skb) 932 return ERR_PTR(err); 933 934 skb_reserve(skb, prepad); 935 skb_put(skb, linear); 936 skb->data_len = len - linear; 937 skb->len += len - linear; 938 939 return skb; 940 } 941 942 /* set skb frags from iovec, this can move to core network code for reuse */ 943 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, 944 int offset, size_t count) 945 { 946 int len = iov_length(from, count) - offset; 947 int copy = skb_headlen(skb); 948 int size, offset1 = 0; 949 int i = 0; 950 951 /* Skip over from offset */ 952 while (count && (offset >= from->iov_len)) { 953 offset -= from->iov_len; 954 ++from; 955 --count; 956 } 957 958 /* copy up to skb headlen */ 959 while (count && (copy > 0)) { 960 size = min_t(unsigned int, copy, from->iov_len - offset); 961 if (copy_from_user(skb->data + offset1, from->iov_base + offset, 962 size)) 963 return -EFAULT; 964 if (copy > size) { 965 ++from; 966 --count; 967 offset = 0; 968 } else 969 offset += size; 970 copy -= size; 971 offset1 += size; 972 } 973 974 if (len == offset1) 975 return 0; 976 977 while (count--) { 978 struct page *page[MAX_SKB_FRAGS]; 979 int num_pages; 980 unsigned long base; 981 unsigned long truesize; 982 983 len = from->iov_len - offset; 984 if (!len) { 985 offset = 0; 986 ++from; 987 continue; 988 } 989 base = (unsigned long)from->iov_base + offset; 990 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; 991 if (i + size > MAX_SKB_FRAGS) 992 return -EMSGSIZE; 993 num_pages = get_user_pages_fast(base, size, 0, &page[i]); 994 if (num_pages != size) { 995 for (i = 0; i < num_pages; i++) 996 put_page(page[i]); 997 return -EFAULT; 998 } 999 truesize = size * PAGE_SIZE; 1000 skb->data_len += len; 1001 skb->len += len; 1002 skb->truesize += truesize; 1003 atomic_add(truesize, &skb->sk->sk_wmem_alloc); 1004 while (len) { 1005 int off = base & ~PAGE_MASK; 1006 int size = min_t(int, len, PAGE_SIZE - off); 1007 __skb_fill_page_desc(skb, i, page[i], off, size); 1008 skb_shinfo(skb)->nr_frags++; 1009 /* increase sk_wmem_alloc */ 1010 base += size; 1011 len -= size; 1012 i++; 1013 } 1014 offset = 0; 1015 ++from; 1016 } 1017 return 0; 1018 } 1019 1020 /* Get packet from user space buffer */ 1021 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1022 void *msg_control, const struct iovec *iv, 1023 size_t total_len, size_t count, int noblock) 1024 { 1025 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1026 struct sk_buff *skb; 1027 size_t len = total_len, align = NET_SKB_PAD; 1028 struct virtio_net_hdr gso = { 0 }; 1029 int offset = 0; 1030 int copylen; 1031 bool zerocopy = false; 1032 int err; 1033 u32 rxhash; 1034 1035 if (!(tun->flags & TUN_NO_PI)) { 1036 if ((len -= sizeof(pi)) > total_len) 1037 return -EINVAL; 1038 1039 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) 1040 return -EFAULT; 1041 offset += sizeof(pi); 1042 } 1043 1044 if (tun->flags & TUN_VNET_HDR) { 1045 if ((len -= tun->vnet_hdr_sz) > total_len) 1046 return -EINVAL; 1047 1048 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) 1049 return -EFAULT; 1050 1051 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1052 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) 1053 gso.hdr_len = gso.csum_start + gso.csum_offset + 2; 1054 1055 if (gso.hdr_len > len) 1056 return -EINVAL; 1057 offset += tun->vnet_hdr_sz; 1058 } 1059 1060 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { 1061 align += NET_IP_ALIGN; 1062 if (unlikely(len < ETH_HLEN || 1063 (gso.hdr_len && gso.hdr_len < ETH_HLEN))) 1064 return -EINVAL; 1065 } 1066 1067 if (msg_control) 1068 zerocopy = true; 1069 1070 if (zerocopy) { 1071 /* Userspace may produce vectors with count greater than 1072 * MAX_SKB_FRAGS, so we need to linearize parts of the skb 1073 * to let the rest of data to be fit in the frags. 1074 */ 1075 if (count > MAX_SKB_FRAGS) { 1076 copylen = iov_length(iv, count - MAX_SKB_FRAGS); 1077 if (copylen < offset) 1078 copylen = 0; 1079 else 1080 copylen -= offset; 1081 } else 1082 copylen = 0; 1083 /* There are 256 bytes to be copied in skb, so there is enough 1084 * room for skb expand head in case it is used. 1085 * The rest of the buffer is mapped from userspace. 1086 */ 1087 if (copylen < gso.hdr_len) 1088 copylen = gso.hdr_len; 1089 if (!copylen) 1090 copylen = GOODCOPY_LEN; 1091 } else 1092 copylen = len; 1093 1094 skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, noblock); 1095 if (IS_ERR(skb)) { 1096 if (PTR_ERR(skb) != -EAGAIN) 1097 tun->dev->stats.rx_dropped++; 1098 return PTR_ERR(skb); 1099 } 1100 1101 if (zerocopy) 1102 err = zerocopy_sg_from_iovec(skb, iv, offset, count); 1103 else 1104 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len); 1105 1106 if (err) { 1107 tun->dev->stats.rx_dropped++; 1108 kfree_skb(skb); 1109 return -EFAULT; 1110 } 1111 1112 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1113 if (!skb_partial_csum_set(skb, gso.csum_start, 1114 gso.csum_offset)) { 1115 tun->dev->stats.rx_frame_errors++; 1116 kfree_skb(skb); 1117 return -EINVAL; 1118 } 1119 } 1120 1121 switch (tun->flags & TUN_TYPE_MASK) { 1122 case TUN_TUN_DEV: 1123 if (tun->flags & TUN_NO_PI) { 1124 switch (skb->data[0] & 0xf0) { 1125 case 0x40: 1126 pi.proto = htons(ETH_P_IP); 1127 break; 1128 case 0x60: 1129 pi.proto = htons(ETH_P_IPV6); 1130 break; 1131 default: 1132 tun->dev->stats.rx_dropped++; 1133 kfree_skb(skb); 1134 return -EINVAL; 1135 } 1136 } 1137 1138 skb_reset_mac_header(skb); 1139 skb->protocol = pi.proto; 1140 skb->dev = tun->dev; 1141 break; 1142 case TUN_TAP_DEV: 1143 skb->protocol = eth_type_trans(skb, tun->dev); 1144 break; 1145 } 1146 1147 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1148 pr_debug("GSO!\n"); 1149 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1150 case VIRTIO_NET_HDR_GSO_TCPV4: 1151 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1152 break; 1153 case VIRTIO_NET_HDR_GSO_TCPV6: 1154 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1155 break; 1156 case VIRTIO_NET_HDR_GSO_UDP: 1157 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1158 break; 1159 default: 1160 tun->dev->stats.rx_frame_errors++; 1161 kfree_skb(skb); 1162 return -EINVAL; 1163 } 1164 1165 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1166 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1167 1168 skb_shinfo(skb)->gso_size = gso.gso_size; 1169 if (skb_shinfo(skb)->gso_size == 0) { 1170 tun->dev->stats.rx_frame_errors++; 1171 kfree_skb(skb); 1172 return -EINVAL; 1173 } 1174 1175 /* Header must be checked, and gso_segs computed. */ 1176 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1177 skb_shinfo(skb)->gso_segs = 0; 1178 } 1179 1180 /* copy skb_ubuf_info for callback when skb has no error */ 1181 if (zerocopy) { 1182 skb_shinfo(skb)->destructor_arg = msg_control; 1183 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1184 } 1185 1186 skb_reset_network_header(skb); 1187 rxhash = skb_get_rxhash(skb); 1188 netif_rx_ni(skb); 1189 1190 tun->dev->stats.rx_packets++; 1191 tun->dev->stats.rx_bytes += len; 1192 1193 tun_flow_update(tun, rxhash, tfile->queue_index); 1194 return total_len; 1195 } 1196 1197 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 1198 unsigned long count, loff_t pos) 1199 { 1200 struct file *file = iocb->ki_filp; 1201 struct tun_struct *tun = tun_get(file); 1202 struct tun_file *tfile = file->private_data; 1203 ssize_t result; 1204 1205 if (!tun) 1206 return -EBADFD; 1207 1208 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count); 1209 1210 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count), 1211 count, file->f_flags & O_NONBLOCK); 1212 1213 tun_put(tun); 1214 return result; 1215 } 1216 1217 /* Put packet to the user space buffer */ 1218 static ssize_t tun_put_user(struct tun_struct *tun, 1219 struct tun_file *tfile, 1220 struct sk_buff *skb, 1221 const struct iovec *iv, int len) 1222 { 1223 struct tun_pi pi = { 0, skb->protocol }; 1224 ssize_t total = 0; 1225 1226 if (!(tun->flags & TUN_NO_PI)) { 1227 if ((len -= sizeof(pi)) < 0) 1228 return -EINVAL; 1229 1230 if (len < skb->len) { 1231 /* Packet will be striped */ 1232 pi.flags |= TUN_PKT_STRIP; 1233 } 1234 1235 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi))) 1236 return -EFAULT; 1237 total += sizeof(pi); 1238 } 1239 1240 if (tun->flags & TUN_VNET_HDR) { 1241 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1242 if ((len -= tun->vnet_hdr_sz) < 0) 1243 return -EINVAL; 1244 1245 if (skb_is_gso(skb)) { 1246 struct skb_shared_info *sinfo = skb_shinfo(skb); 1247 1248 /* This is a hint as to how much should be linear. */ 1249 gso.hdr_len = skb_headlen(skb); 1250 gso.gso_size = sinfo->gso_size; 1251 if (sinfo->gso_type & SKB_GSO_TCPV4) 1252 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1253 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1254 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1255 else if (sinfo->gso_type & SKB_GSO_UDP) 1256 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1257 else { 1258 pr_err("unexpected GSO type: " 1259 "0x%x, gso_size %d, hdr_len %d\n", 1260 sinfo->gso_type, gso.gso_size, 1261 gso.hdr_len); 1262 print_hex_dump(KERN_ERR, "tun: ", 1263 DUMP_PREFIX_NONE, 1264 16, 1, skb->head, 1265 min((int)gso.hdr_len, 64), true); 1266 WARN_ON_ONCE(1); 1267 return -EINVAL; 1268 } 1269 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1270 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1271 } else 1272 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1273 1274 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1275 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1276 gso.csum_start = skb_checksum_start_offset(skb); 1277 gso.csum_offset = skb->csum_offset; 1278 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1279 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1280 } /* else everything is zero */ 1281 1282 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, 1283 sizeof(gso)))) 1284 return -EFAULT; 1285 total += tun->vnet_hdr_sz; 1286 } 1287 1288 len = min_t(int, skb->len, len); 1289 1290 skb_copy_datagram_const_iovec(skb, 0, iv, total, len); 1291 total += skb->len; 1292 1293 tun->dev->stats.tx_packets++; 1294 tun->dev->stats.tx_bytes += len; 1295 1296 return total; 1297 } 1298 1299 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1300 struct kiocb *iocb, const struct iovec *iv, 1301 ssize_t len, int noblock) 1302 { 1303 DECLARE_WAITQUEUE(wait, current); 1304 struct sk_buff *skb; 1305 ssize_t ret = 0; 1306 1307 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1308 1309 if (unlikely(!noblock)) 1310 add_wait_queue(&tfile->wq.wait, &wait); 1311 while (len) { 1312 current->state = TASK_INTERRUPTIBLE; 1313 1314 /* Read frames from the queue */ 1315 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) { 1316 if (noblock) { 1317 ret = -EAGAIN; 1318 break; 1319 } 1320 if (signal_pending(current)) { 1321 ret = -ERESTARTSYS; 1322 break; 1323 } 1324 if (tun->dev->reg_state != NETREG_REGISTERED) { 1325 ret = -EIO; 1326 break; 1327 } 1328 1329 /* Nothing to read, let's sleep */ 1330 schedule(); 1331 continue; 1332 } 1333 1334 ret = tun_put_user(tun, tfile, skb, iv, len); 1335 kfree_skb(skb); 1336 break; 1337 } 1338 1339 current->state = TASK_RUNNING; 1340 if (unlikely(!noblock)) 1341 remove_wait_queue(&tfile->wq.wait, &wait); 1342 1343 return ret; 1344 } 1345 1346 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 1347 unsigned long count, loff_t pos) 1348 { 1349 struct file *file = iocb->ki_filp; 1350 struct tun_file *tfile = file->private_data; 1351 struct tun_struct *tun = __tun_get(tfile); 1352 ssize_t len, ret; 1353 1354 if (!tun) 1355 return -EBADFD; 1356 len = iov_length(iv, count); 1357 if (len < 0) { 1358 ret = -EINVAL; 1359 goto out; 1360 } 1361 1362 ret = tun_do_read(tun, tfile, iocb, iv, len, 1363 file->f_flags & O_NONBLOCK); 1364 ret = min_t(ssize_t, ret, len); 1365 out: 1366 tun_put(tun); 1367 return ret; 1368 } 1369 1370 static void tun_free_netdev(struct net_device *dev) 1371 { 1372 struct tun_struct *tun = netdev_priv(dev); 1373 1374 BUG_ON(!(list_empty(&tun->disabled))); 1375 tun_flow_uninit(tun); 1376 free_netdev(dev); 1377 } 1378 1379 static void tun_setup(struct net_device *dev) 1380 { 1381 struct tun_struct *tun = netdev_priv(dev); 1382 1383 tun->owner = INVALID_UID; 1384 tun->group = INVALID_GID; 1385 1386 dev->ethtool_ops = &tun_ethtool_ops; 1387 dev->destructor = tun_free_netdev; 1388 } 1389 1390 /* Trivial set of netlink ops to allow deleting tun or tap 1391 * device with netlink. 1392 */ 1393 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1394 { 1395 return -EINVAL; 1396 } 1397 1398 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1399 .kind = DRV_NAME, 1400 .priv_size = sizeof(struct tun_struct), 1401 .setup = tun_setup, 1402 .validate = tun_validate, 1403 }; 1404 1405 static void tun_sock_write_space(struct sock *sk) 1406 { 1407 struct tun_file *tfile; 1408 wait_queue_head_t *wqueue; 1409 1410 if (!sock_writeable(sk)) 1411 return; 1412 1413 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1414 return; 1415 1416 wqueue = sk_sleep(sk); 1417 if (wqueue && waitqueue_active(wqueue)) 1418 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1419 POLLWRNORM | POLLWRBAND); 1420 1421 tfile = container_of(sk, struct tun_file, sk); 1422 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1423 } 1424 1425 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1426 struct msghdr *m, size_t total_len) 1427 { 1428 int ret; 1429 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1430 struct tun_struct *tun = __tun_get(tfile); 1431 1432 if (!tun) 1433 return -EBADFD; 1434 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len, 1435 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); 1436 tun_put(tun); 1437 return ret; 1438 } 1439 1440 1441 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1442 struct msghdr *m, size_t total_len, 1443 int flags) 1444 { 1445 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1446 struct tun_struct *tun = __tun_get(tfile); 1447 int ret; 1448 1449 if (!tun) 1450 return -EBADFD; 1451 1452 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) 1453 return -EINVAL; 1454 ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len, 1455 flags & MSG_DONTWAIT); 1456 if (ret > total_len) { 1457 m->msg_flags |= MSG_TRUNC; 1458 ret = flags & MSG_TRUNC ? ret : total_len; 1459 } 1460 tun_put(tun); 1461 return ret; 1462 } 1463 1464 static int tun_release(struct socket *sock) 1465 { 1466 if (sock->sk) 1467 sock_put(sock->sk); 1468 return 0; 1469 } 1470 1471 /* Ops structure to mimic raw sockets with tun */ 1472 static const struct proto_ops tun_socket_ops = { 1473 .sendmsg = tun_sendmsg, 1474 .recvmsg = tun_recvmsg, 1475 .release = tun_release, 1476 }; 1477 1478 static struct proto tun_proto = { 1479 .name = "tun", 1480 .owner = THIS_MODULE, 1481 .obj_size = sizeof(struct tun_file), 1482 }; 1483 1484 static int tun_flags(struct tun_struct *tun) 1485 { 1486 int flags = 0; 1487 1488 if (tun->flags & TUN_TUN_DEV) 1489 flags |= IFF_TUN; 1490 else 1491 flags |= IFF_TAP; 1492 1493 if (tun->flags & TUN_NO_PI) 1494 flags |= IFF_NO_PI; 1495 1496 /* This flag has no real effect. We track the value for backwards 1497 * compatibility. 1498 */ 1499 if (tun->flags & TUN_ONE_QUEUE) 1500 flags |= IFF_ONE_QUEUE; 1501 1502 if (tun->flags & TUN_VNET_HDR) 1503 flags |= IFF_VNET_HDR; 1504 1505 if (tun->flags & TUN_TAP_MQ) 1506 flags |= IFF_MULTI_QUEUE; 1507 1508 return flags; 1509 } 1510 1511 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1512 char *buf) 1513 { 1514 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1515 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1516 } 1517 1518 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1519 char *buf) 1520 { 1521 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1522 return uid_valid(tun->owner)? 1523 sprintf(buf, "%u\n", 1524 from_kuid_munged(current_user_ns(), tun->owner)): 1525 sprintf(buf, "-1\n"); 1526 } 1527 1528 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1529 char *buf) 1530 { 1531 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1532 return gid_valid(tun->group) ? 1533 sprintf(buf, "%u\n", 1534 from_kgid_munged(current_user_ns(), tun->group)): 1535 sprintf(buf, "-1\n"); 1536 } 1537 1538 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1539 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1540 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1541 1542 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1543 { 1544 struct tun_struct *tun; 1545 struct tun_file *tfile = file->private_data; 1546 struct net_device *dev; 1547 int err; 1548 1549 if (tfile->detached) 1550 return -EINVAL; 1551 1552 dev = __dev_get_by_name(net, ifr->ifr_name); 1553 if (dev) { 1554 if (ifr->ifr_flags & IFF_TUN_EXCL) 1555 return -EBUSY; 1556 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1557 tun = netdev_priv(dev); 1558 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1559 tun = netdev_priv(dev); 1560 else 1561 return -EINVAL; 1562 1563 if (tun_not_capable(tun)) 1564 return -EPERM; 1565 err = security_tun_dev_attach(tfile->socket.sk); 1566 if (err < 0) 1567 return err; 1568 1569 err = tun_attach(tun, file); 1570 if (err < 0) 1571 return err; 1572 1573 if (tun->flags & TUN_TAP_MQ && 1574 (tun->numqueues + tun->numdisabled > 1)) 1575 return err; 1576 } 1577 else { 1578 char *name; 1579 unsigned long flags = 0; 1580 1581 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1582 return -EPERM; 1583 err = security_tun_dev_create(); 1584 if (err < 0) 1585 return err; 1586 1587 /* Set dev type */ 1588 if (ifr->ifr_flags & IFF_TUN) { 1589 /* TUN device */ 1590 flags |= TUN_TUN_DEV; 1591 name = "tun%d"; 1592 } else if (ifr->ifr_flags & IFF_TAP) { 1593 /* TAP device */ 1594 flags |= TUN_TAP_DEV; 1595 name = "tap%d"; 1596 } else 1597 return -EINVAL; 1598 1599 if (*ifr->ifr_name) 1600 name = ifr->ifr_name; 1601 1602 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1603 tun_setup, 1604 MAX_TAP_QUEUES, MAX_TAP_QUEUES); 1605 if (!dev) 1606 return -ENOMEM; 1607 1608 dev_net_set(dev, net); 1609 dev->rtnl_link_ops = &tun_link_ops; 1610 1611 tun = netdev_priv(dev); 1612 tun->dev = dev; 1613 tun->flags = flags; 1614 tun->txflt.count = 0; 1615 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1616 1617 tun->filter_attached = false; 1618 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1619 1620 spin_lock_init(&tun->lock); 1621 1622 security_tun_dev_post_create(&tfile->sk); 1623 1624 tun_net_init(dev); 1625 1626 err = tun_flow_init(tun); 1627 if (err < 0) 1628 goto err_free_dev; 1629 1630 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1631 TUN_USER_FEATURES; 1632 dev->features = dev->hw_features; 1633 1634 INIT_LIST_HEAD(&tun->disabled); 1635 err = tun_attach(tun, file); 1636 if (err < 0) 1637 goto err_free_dev; 1638 1639 err = register_netdevice(tun->dev); 1640 if (err < 0) 1641 goto err_free_dev; 1642 1643 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1644 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1645 device_create_file(&tun->dev->dev, &dev_attr_group)) 1646 pr_err("Failed to create tun sysfs files\n"); 1647 1648 netif_carrier_on(tun->dev); 1649 } 1650 1651 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1652 1653 if (ifr->ifr_flags & IFF_NO_PI) 1654 tun->flags |= TUN_NO_PI; 1655 else 1656 tun->flags &= ~TUN_NO_PI; 1657 1658 /* This flag has no real effect. We track the value for backwards 1659 * compatibility. 1660 */ 1661 if (ifr->ifr_flags & IFF_ONE_QUEUE) 1662 tun->flags |= TUN_ONE_QUEUE; 1663 else 1664 tun->flags &= ~TUN_ONE_QUEUE; 1665 1666 if (ifr->ifr_flags & IFF_VNET_HDR) 1667 tun->flags |= TUN_VNET_HDR; 1668 else 1669 tun->flags &= ~TUN_VNET_HDR; 1670 1671 if (ifr->ifr_flags & IFF_MULTI_QUEUE) 1672 tun->flags |= TUN_TAP_MQ; 1673 else 1674 tun->flags &= ~TUN_TAP_MQ; 1675 1676 /* Make sure persistent devices do not get stuck in 1677 * xoff state. 1678 */ 1679 if (netif_running(tun->dev)) 1680 netif_tx_wake_all_queues(tun->dev); 1681 1682 strcpy(ifr->ifr_name, tun->dev->name); 1683 return 0; 1684 1685 err_free_dev: 1686 free_netdev(dev); 1687 return err; 1688 } 1689 1690 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1691 struct ifreq *ifr) 1692 { 1693 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1694 1695 strcpy(ifr->ifr_name, tun->dev->name); 1696 1697 ifr->ifr_flags = tun_flags(tun); 1698 1699 } 1700 1701 /* This is like a cut-down ethtool ops, except done via tun fd so no 1702 * privs required. */ 1703 static int set_offload(struct tun_struct *tun, unsigned long arg) 1704 { 1705 netdev_features_t features = 0; 1706 1707 if (arg & TUN_F_CSUM) { 1708 features |= NETIF_F_HW_CSUM; 1709 arg &= ~TUN_F_CSUM; 1710 1711 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1712 if (arg & TUN_F_TSO_ECN) { 1713 features |= NETIF_F_TSO_ECN; 1714 arg &= ~TUN_F_TSO_ECN; 1715 } 1716 if (arg & TUN_F_TSO4) 1717 features |= NETIF_F_TSO; 1718 if (arg & TUN_F_TSO6) 1719 features |= NETIF_F_TSO6; 1720 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1721 } 1722 1723 if (arg & TUN_F_UFO) { 1724 features |= NETIF_F_UFO; 1725 arg &= ~TUN_F_UFO; 1726 } 1727 } 1728 1729 /* This gives the user a way to test for new features in future by 1730 * trying to set them. */ 1731 if (arg) 1732 return -EINVAL; 1733 1734 tun->set_features = features; 1735 netdev_update_features(tun->dev); 1736 1737 return 0; 1738 } 1739 1740 static void tun_detach_filter(struct tun_struct *tun, int n) 1741 { 1742 int i; 1743 struct tun_file *tfile; 1744 1745 for (i = 0; i < n; i++) { 1746 tfile = rtnl_dereference(tun->tfiles[i]); 1747 sk_detach_filter(tfile->socket.sk); 1748 } 1749 1750 tun->filter_attached = false; 1751 } 1752 1753 static int tun_attach_filter(struct tun_struct *tun) 1754 { 1755 int i, ret = 0; 1756 struct tun_file *tfile; 1757 1758 for (i = 0; i < tun->numqueues; i++) { 1759 tfile = rtnl_dereference(tun->tfiles[i]); 1760 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1761 if (ret) { 1762 tun_detach_filter(tun, i); 1763 return ret; 1764 } 1765 } 1766 1767 tun->filter_attached = true; 1768 return ret; 1769 } 1770 1771 static void tun_set_sndbuf(struct tun_struct *tun) 1772 { 1773 struct tun_file *tfile; 1774 int i; 1775 1776 for (i = 0; i < tun->numqueues; i++) { 1777 tfile = rtnl_dereference(tun->tfiles[i]); 1778 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1779 } 1780 } 1781 1782 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1783 { 1784 struct tun_file *tfile = file->private_data; 1785 struct tun_struct *tun; 1786 int ret = 0; 1787 1788 rtnl_lock(); 1789 1790 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1791 tun = tfile->detached; 1792 if (!tun) 1793 ret = -EINVAL; 1794 else 1795 ret = tun_attach(tun, file); 1796 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1797 tun = rtnl_dereference(tfile->tun); 1798 if (!tun || !(tun->flags & TUN_TAP_MQ)) 1799 ret = -EINVAL; 1800 else 1801 __tun_detach(tfile, false); 1802 } else 1803 ret = -EINVAL; 1804 1805 rtnl_unlock(); 1806 return ret; 1807 } 1808 1809 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1810 unsigned long arg, int ifreq_len) 1811 { 1812 struct tun_file *tfile = file->private_data; 1813 struct tun_struct *tun; 1814 void __user* argp = (void __user*)arg; 1815 struct ifreq ifr; 1816 kuid_t owner; 1817 kgid_t group; 1818 int sndbuf; 1819 int vnet_hdr_sz; 1820 int ret; 1821 1822 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1823 if (copy_from_user(&ifr, argp, ifreq_len)) 1824 return -EFAULT; 1825 } else { 1826 memset(&ifr, 0, sizeof(ifr)); 1827 } 1828 if (cmd == TUNGETFEATURES) { 1829 /* Currently this just means: "what IFF flags are valid?". 1830 * This is needed because we never checked for invalid flags on 1831 * TUNSETIFF. */ 1832 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | 1833 IFF_VNET_HDR | IFF_MULTI_QUEUE, 1834 (unsigned int __user*)argp); 1835 } else if (cmd == TUNSETQUEUE) 1836 return tun_set_queue(file, &ifr); 1837 1838 ret = 0; 1839 rtnl_lock(); 1840 1841 tun = __tun_get(tfile); 1842 if (cmd == TUNSETIFF && !tun) { 1843 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1844 1845 ret = tun_set_iff(tfile->net, file, &ifr); 1846 1847 if (ret) 1848 goto unlock; 1849 1850 if (copy_to_user(argp, &ifr, ifreq_len)) 1851 ret = -EFAULT; 1852 goto unlock; 1853 } 1854 1855 ret = -EBADFD; 1856 if (!tun) 1857 goto unlock; 1858 1859 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1860 1861 ret = 0; 1862 switch (cmd) { 1863 case TUNGETIFF: 1864 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1865 1866 if (copy_to_user(argp, &ifr, ifreq_len)) 1867 ret = -EFAULT; 1868 break; 1869 1870 case TUNSETNOCSUM: 1871 /* Disable/Enable checksum */ 1872 1873 /* [unimplemented] */ 1874 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1875 arg ? "disabled" : "enabled"); 1876 break; 1877 1878 case TUNSETPERSIST: 1879 /* Disable/Enable persist mode. Keep an extra reference to the 1880 * module to prevent the module being unprobed. 1881 */ 1882 if (arg && !(tun->flags & TUN_PERSIST)) { 1883 tun->flags |= TUN_PERSIST; 1884 __module_get(THIS_MODULE); 1885 } 1886 if (!arg && (tun->flags & TUN_PERSIST)) { 1887 tun->flags &= ~TUN_PERSIST; 1888 module_put(THIS_MODULE); 1889 } 1890 1891 tun_debug(KERN_INFO, tun, "persist %s\n", 1892 arg ? "enabled" : "disabled"); 1893 break; 1894 1895 case TUNSETOWNER: 1896 /* Set owner of the device */ 1897 owner = make_kuid(current_user_ns(), arg); 1898 if (!uid_valid(owner)) { 1899 ret = -EINVAL; 1900 break; 1901 } 1902 tun->owner = owner; 1903 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1904 from_kuid(&init_user_ns, tun->owner)); 1905 break; 1906 1907 case TUNSETGROUP: 1908 /* Set group of the device */ 1909 group = make_kgid(current_user_ns(), arg); 1910 if (!gid_valid(group)) { 1911 ret = -EINVAL; 1912 break; 1913 } 1914 tun->group = group; 1915 tun_debug(KERN_INFO, tun, "group set to %u\n", 1916 from_kgid(&init_user_ns, tun->group)); 1917 break; 1918 1919 case TUNSETLINK: 1920 /* Only allow setting the type when the interface is down */ 1921 if (tun->dev->flags & IFF_UP) { 1922 tun_debug(KERN_INFO, tun, 1923 "Linktype set failed because interface is up\n"); 1924 ret = -EBUSY; 1925 } else { 1926 tun->dev->type = (int) arg; 1927 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1928 tun->dev->type); 1929 ret = 0; 1930 } 1931 break; 1932 1933 #ifdef TUN_DEBUG 1934 case TUNSETDEBUG: 1935 tun->debug = arg; 1936 break; 1937 #endif 1938 case TUNSETOFFLOAD: 1939 ret = set_offload(tun, arg); 1940 break; 1941 1942 case TUNSETTXFILTER: 1943 /* Can be set only for TAPs */ 1944 ret = -EINVAL; 1945 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 1946 break; 1947 ret = update_filter(&tun->txflt, (void __user *)arg); 1948 break; 1949 1950 case SIOCGIFHWADDR: 1951 /* Get hw address */ 1952 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 1953 ifr.ifr_hwaddr.sa_family = tun->dev->type; 1954 if (copy_to_user(argp, &ifr, ifreq_len)) 1955 ret = -EFAULT; 1956 break; 1957 1958 case SIOCSIFHWADDR: 1959 /* Set hw address */ 1960 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 1961 ifr.ifr_hwaddr.sa_data); 1962 1963 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 1964 break; 1965 1966 case TUNGETSNDBUF: 1967 sndbuf = tfile->socket.sk->sk_sndbuf; 1968 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 1969 ret = -EFAULT; 1970 break; 1971 1972 case TUNSETSNDBUF: 1973 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 1974 ret = -EFAULT; 1975 break; 1976 } 1977 1978 tun->sndbuf = sndbuf; 1979 tun_set_sndbuf(tun); 1980 break; 1981 1982 case TUNGETVNETHDRSZ: 1983 vnet_hdr_sz = tun->vnet_hdr_sz; 1984 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 1985 ret = -EFAULT; 1986 break; 1987 1988 case TUNSETVNETHDRSZ: 1989 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 1990 ret = -EFAULT; 1991 break; 1992 } 1993 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 1994 ret = -EINVAL; 1995 break; 1996 } 1997 1998 tun->vnet_hdr_sz = vnet_hdr_sz; 1999 break; 2000 2001 case TUNATTACHFILTER: 2002 /* Can be set only for TAPs */ 2003 ret = -EINVAL; 2004 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2005 break; 2006 ret = -EFAULT; 2007 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2008 break; 2009 2010 ret = tun_attach_filter(tun); 2011 break; 2012 2013 case TUNDETACHFILTER: 2014 /* Can be set only for TAPs */ 2015 ret = -EINVAL; 2016 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2017 break; 2018 ret = 0; 2019 tun_detach_filter(tun, tun->numqueues); 2020 break; 2021 2022 default: 2023 ret = -EINVAL; 2024 break; 2025 } 2026 2027 unlock: 2028 rtnl_unlock(); 2029 if (tun) 2030 tun_put(tun); 2031 return ret; 2032 } 2033 2034 static long tun_chr_ioctl(struct file *file, 2035 unsigned int cmd, unsigned long arg) 2036 { 2037 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2038 } 2039 2040 #ifdef CONFIG_COMPAT 2041 static long tun_chr_compat_ioctl(struct file *file, 2042 unsigned int cmd, unsigned long arg) 2043 { 2044 switch (cmd) { 2045 case TUNSETIFF: 2046 case TUNGETIFF: 2047 case TUNSETTXFILTER: 2048 case TUNGETSNDBUF: 2049 case TUNSETSNDBUF: 2050 case SIOCGIFHWADDR: 2051 case SIOCSIFHWADDR: 2052 arg = (unsigned long)compat_ptr(arg); 2053 break; 2054 default: 2055 arg = (compat_ulong_t)arg; 2056 break; 2057 } 2058 2059 /* 2060 * compat_ifreq is shorter than ifreq, so we must not access beyond 2061 * the end of that structure. All fields that are used in this 2062 * driver are compatible though, we don't need to convert the 2063 * contents. 2064 */ 2065 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2066 } 2067 #endif /* CONFIG_COMPAT */ 2068 2069 static int tun_chr_fasync(int fd, struct file *file, int on) 2070 { 2071 struct tun_file *tfile = file->private_data; 2072 int ret; 2073 2074 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2075 goto out; 2076 2077 if (on) { 2078 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2079 if (ret) 2080 goto out; 2081 tfile->flags |= TUN_FASYNC; 2082 } else 2083 tfile->flags &= ~TUN_FASYNC; 2084 ret = 0; 2085 out: 2086 return ret; 2087 } 2088 2089 static int tun_chr_open(struct inode *inode, struct file * file) 2090 { 2091 struct tun_file *tfile; 2092 2093 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2094 2095 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2096 &tun_proto); 2097 if (!tfile) 2098 return -ENOMEM; 2099 rcu_assign_pointer(tfile->tun, NULL); 2100 tfile->net = get_net(current->nsproxy->net_ns); 2101 tfile->flags = 0; 2102 2103 rcu_assign_pointer(tfile->socket.wq, &tfile->wq); 2104 init_waitqueue_head(&tfile->wq.wait); 2105 2106 tfile->socket.file = file; 2107 tfile->socket.ops = &tun_socket_ops; 2108 2109 sock_init_data(&tfile->socket, &tfile->sk); 2110 sk_change_net(&tfile->sk, tfile->net); 2111 2112 tfile->sk.sk_write_space = tun_sock_write_space; 2113 tfile->sk.sk_sndbuf = INT_MAX; 2114 2115 file->private_data = tfile; 2116 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2117 INIT_LIST_HEAD(&tfile->next); 2118 2119 return 0; 2120 } 2121 2122 static int tun_chr_close(struct inode *inode, struct file *file) 2123 { 2124 struct tun_file *tfile = file->private_data; 2125 struct net *net = tfile->net; 2126 2127 tun_detach(tfile, true); 2128 put_net(net); 2129 2130 return 0; 2131 } 2132 2133 static const struct file_operations tun_fops = { 2134 .owner = THIS_MODULE, 2135 .llseek = no_llseek, 2136 .read = do_sync_read, 2137 .aio_read = tun_chr_aio_read, 2138 .write = do_sync_write, 2139 .aio_write = tun_chr_aio_write, 2140 .poll = tun_chr_poll, 2141 .unlocked_ioctl = tun_chr_ioctl, 2142 #ifdef CONFIG_COMPAT 2143 .compat_ioctl = tun_chr_compat_ioctl, 2144 #endif 2145 .open = tun_chr_open, 2146 .release = tun_chr_close, 2147 .fasync = tun_chr_fasync 2148 }; 2149 2150 static struct miscdevice tun_miscdev = { 2151 .minor = TUN_MINOR, 2152 .name = "tun", 2153 .nodename = "net/tun", 2154 .fops = &tun_fops, 2155 }; 2156 2157 /* ethtool interface */ 2158 2159 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2160 { 2161 cmd->supported = 0; 2162 cmd->advertising = 0; 2163 ethtool_cmd_speed_set(cmd, SPEED_10); 2164 cmd->duplex = DUPLEX_FULL; 2165 cmd->port = PORT_TP; 2166 cmd->phy_address = 0; 2167 cmd->transceiver = XCVR_INTERNAL; 2168 cmd->autoneg = AUTONEG_DISABLE; 2169 cmd->maxtxpkt = 0; 2170 cmd->maxrxpkt = 0; 2171 return 0; 2172 } 2173 2174 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2175 { 2176 struct tun_struct *tun = netdev_priv(dev); 2177 2178 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2179 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2180 2181 switch (tun->flags & TUN_TYPE_MASK) { 2182 case TUN_TUN_DEV: 2183 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2184 break; 2185 case TUN_TAP_DEV: 2186 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2187 break; 2188 } 2189 } 2190 2191 static u32 tun_get_msglevel(struct net_device *dev) 2192 { 2193 #ifdef TUN_DEBUG 2194 struct tun_struct *tun = netdev_priv(dev); 2195 return tun->debug; 2196 #else 2197 return -EOPNOTSUPP; 2198 #endif 2199 } 2200 2201 static void tun_set_msglevel(struct net_device *dev, u32 value) 2202 { 2203 #ifdef TUN_DEBUG 2204 struct tun_struct *tun = netdev_priv(dev); 2205 tun->debug = value; 2206 #endif 2207 } 2208 2209 static const struct ethtool_ops tun_ethtool_ops = { 2210 .get_settings = tun_get_settings, 2211 .get_drvinfo = tun_get_drvinfo, 2212 .get_msglevel = tun_get_msglevel, 2213 .set_msglevel = tun_set_msglevel, 2214 .get_link = ethtool_op_get_link, 2215 }; 2216 2217 2218 static int __init tun_init(void) 2219 { 2220 int ret = 0; 2221 2222 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2223 pr_info("%s\n", DRV_COPYRIGHT); 2224 2225 ret = rtnl_link_register(&tun_link_ops); 2226 if (ret) { 2227 pr_err("Can't register link_ops\n"); 2228 goto err_linkops; 2229 } 2230 2231 ret = misc_register(&tun_miscdev); 2232 if (ret) { 2233 pr_err("Can't register misc device %d\n", TUN_MINOR); 2234 goto err_misc; 2235 } 2236 return 0; 2237 err_misc: 2238 rtnl_link_unregister(&tun_link_ops); 2239 err_linkops: 2240 return ret; 2241 } 2242 2243 static void tun_cleanup(void) 2244 { 2245 misc_deregister(&tun_miscdev); 2246 rtnl_link_unregister(&tun_link_ops); 2247 } 2248 2249 /* Get an underlying socket object from tun file. Returns error unless file is 2250 * attached to a device. The returned object works like a packet socket, it 2251 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2252 * holding a reference to the file for as long as the socket is in use. */ 2253 struct socket *tun_get_socket(struct file *file) 2254 { 2255 struct tun_file *tfile; 2256 if (file->f_op != &tun_fops) 2257 return ERR_PTR(-EINVAL); 2258 tfile = file->private_data; 2259 if (!tfile) 2260 return ERR_PTR(-EBADFD); 2261 return &tfile->socket; 2262 } 2263 EXPORT_SYMBOL_GPL(tun_get_socket); 2264 2265 module_init(tun_init); 2266 module_exit(tun_cleanup); 2267 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2268 MODULE_AUTHOR(DRV_COPYRIGHT); 2269 MODULE_LICENSE("GPL"); 2270 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2271 MODULE_ALIAS("devname:net/tun"); 2272