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