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 if (!(tun->flags & TUN_ONE_QUEUE)) { 695 /* Normal queueing mode. */ 696 /* Packet scheduler handles dropping of further packets. */ 697 netif_stop_subqueue(dev, txq); 698 699 /* We won't see all dropped packets individually, so overrun 700 * error is more appropriate. */ 701 dev->stats.tx_fifo_errors++; 702 } else { 703 /* Single queue mode. 704 * Driver handles dropping of all packets itself. */ 705 goto drop; 706 } 707 } 708 709 /* Orphan the skb - required as we might hang on to it 710 * for indefinite time. */ 711 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 712 goto drop; 713 skb_orphan(skb); 714 715 /* Enqueue packet */ 716 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 717 718 /* Notify and wake up reader process */ 719 if (tfile->flags & TUN_FASYNC) 720 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 721 wake_up_interruptible_poll(&tfile->wq.wait, POLLIN | 722 POLLRDNORM | POLLRDBAND); 723 724 rcu_read_unlock(); 725 return NETDEV_TX_OK; 726 727 drop: 728 dev->stats.tx_dropped++; 729 skb_tx_error(skb); 730 kfree_skb(skb); 731 rcu_read_unlock(); 732 return NETDEV_TX_OK; 733 } 734 735 static void tun_net_mclist(struct net_device *dev) 736 { 737 /* 738 * This callback is supposed to deal with mc filter in 739 * _rx_ path and has nothing to do with the _tx_ path. 740 * In rx path we always accept everything userspace gives us. 741 */ 742 } 743 744 #define MIN_MTU 68 745 #define MAX_MTU 65535 746 747 static int 748 tun_net_change_mtu(struct net_device *dev, int new_mtu) 749 { 750 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 751 return -EINVAL; 752 dev->mtu = new_mtu; 753 return 0; 754 } 755 756 static netdev_features_t tun_net_fix_features(struct net_device *dev, 757 netdev_features_t features) 758 { 759 struct tun_struct *tun = netdev_priv(dev); 760 761 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 762 } 763 #ifdef CONFIG_NET_POLL_CONTROLLER 764 static void tun_poll_controller(struct net_device *dev) 765 { 766 /* 767 * Tun only receives frames when: 768 * 1) the char device endpoint gets data from user space 769 * 2) the tun socket gets a sendmsg call from user space 770 * Since both of those are syncronous operations, we are guaranteed 771 * never to have pending data when we poll for it 772 * so theres nothing to do here but return. 773 * We need this though so netpoll recognizes us as an interface that 774 * supports polling, which enables bridge devices in virt setups to 775 * still use netconsole 776 */ 777 return; 778 } 779 #endif 780 static const struct net_device_ops tun_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_select_queue = tun_select_queue, 788 #ifdef CONFIG_NET_POLL_CONTROLLER 789 .ndo_poll_controller = tun_poll_controller, 790 #endif 791 }; 792 793 static const struct net_device_ops tap_netdev_ops = { 794 .ndo_uninit = tun_net_uninit, 795 .ndo_open = tun_net_open, 796 .ndo_stop = tun_net_close, 797 .ndo_start_xmit = tun_net_xmit, 798 .ndo_change_mtu = tun_net_change_mtu, 799 .ndo_fix_features = tun_net_fix_features, 800 .ndo_set_rx_mode = tun_net_mclist, 801 .ndo_set_mac_address = eth_mac_addr, 802 .ndo_validate_addr = eth_validate_addr, 803 .ndo_select_queue = tun_select_queue, 804 #ifdef CONFIG_NET_POLL_CONTROLLER 805 .ndo_poll_controller = tun_poll_controller, 806 #endif 807 }; 808 809 static int tun_flow_init(struct tun_struct *tun) 810 { 811 int i; 812 813 tun->flow_cache = kmem_cache_create("tun_flow_cache", 814 sizeof(struct tun_flow_entry), 0, 0, 815 NULL); 816 if (!tun->flow_cache) 817 return -ENOMEM; 818 819 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 820 INIT_HLIST_HEAD(&tun->flows[i]); 821 822 tun->ageing_time = TUN_FLOW_EXPIRE; 823 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 824 mod_timer(&tun->flow_gc_timer, 825 round_jiffies_up(jiffies + tun->ageing_time)); 826 827 return 0; 828 } 829 830 static void tun_flow_uninit(struct tun_struct *tun) 831 { 832 del_timer_sync(&tun->flow_gc_timer); 833 tun_flow_flush(tun); 834 835 /* Wait for completion of call_rcu()'s */ 836 rcu_barrier(); 837 kmem_cache_destroy(tun->flow_cache); 838 } 839 840 /* Initialize net device. */ 841 static void tun_net_init(struct net_device *dev) 842 { 843 struct tun_struct *tun = netdev_priv(dev); 844 845 switch (tun->flags & TUN_TYPE_MASK) { 846 case TUN_TUN_DEV: 847 dev->netdev_ops = &tun_netdev_ops; 848 849 /* Point-to-Point TUN Device */ 850 dev->hard_header_len = 0; 851 dev->addr_len = 0; 852 dev->mtu = 1500; 853 854 /* Zero header length */ 855 dev->type = ARPHRD_NONE; 856 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 857 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 858 break; 859 860 case TUN_TAP_DEV: 861 dev->netdev_ops = &tap_netdev_ops; 862 /* Ethernet TAP Device */ 863 ether_setup(dev); 864 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 865 866 eth_hw_addr_random(dev); 867 868 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 869 break; 870 } 871 } 872 873 /* Character device part */ 874 875 /* Poll */ 876 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 877 { 878 struct tun_file *tfile = file->private_data; 879 struct tun_struct *tun = __tun_get(tfile); 880 struct sock *sk; 881 unsigned int mask = 0; 882 883 if (!tun) 884 return POLLERR; 885 886 sk = tfile->socket.sk; 887 888 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 889 890 poll_wait(file, &tfile->wq.wait, wait); 891 892 if (!skb_queue_empty(&sk->sk_receive_queue)) 893 mask |= POLLIN | POLLRDNORM; 894 895 if (sock_writeable(sk) || 896 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 897 sock_writeable(sk))) 898 mask |= POLLOUT | POLLWRNORM; 899 900 if (tun->dev->reg_state != NETREG_REGISTERED) 901 mask = POLLERR; 902 903 tun_put(tun); 904 return mask; 905 } 906 907 /* prepad is the amount to reserve at front. len is length after that. 908 * linear is a hint as to how much to copy (usually headers). */ 909 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 910 size_t prepad, size_t len, 911 size_t linear, int noblock) 912 { 913 struct sock *sk = tfile->socket.sk; 914 struct sk_buff *skb; 915 int err; 916 917 /* Under a page? Don't bother with paged skb. */ 918 if (prepad + len < PAGE_SIZE || !linear) 919 linear = len; 920 921 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 922 &err); 923 if (!skb) 924 return ERR_PTR(err); 925 926 skb_reserve(skb, prepad); 927 skb_put(skb, linear); 928 skb->data_len = len - linear; 929 skb->len += len - linear; 930 931 return skb; 932 } 933 934 /* set skb frags from iovec, this can move to core network code for reuse */ 935 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, 936 int offset, size_t count) 937 { 938 int len = iov_length(from, count) - offset; 939 int copy = skb_headlen(skb); 940 int size, offset1 = 0; 941 int i = 0; 942 943 /* Skip over from offset */ 944 while (count && (offset >= from->iov_len)) { 945 offset -= from->iov_len; 946 ++from; 947 --count; 948 } 949 950 /* copy up to skb headlen */ 951 while (count && (copy > 0)) { 952 size = min_t(unsigned int, copy, from->iov_len - offset); 953 if (copy_from_user(skb->data + offset1, from->iov_base + offset, 954 size)) 955 return -EFAULT; 956 if (copy > size) { 957 ++from; 958 --count; 959 offset = 0; 960 } else 961 offset += size; 962 copy -= size; 963 offset1 += size; 964 } 965 966 if (len == offset1) 967 return 0; 968 969 while (count--) { 970 struct page *page[MAX_SKB_FRAGS]; 971 int num_pages; 972 unsigned long base; 973 unsigned long truesize; 974 975 len = from->iov_len - offset; 976 if (!len) { 977 offset = 0; 978 ++from; 979 continue; 980 } 981 base = (unsigned long)from->iov_base + offset; 982 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; 983 if (i + size > MAX_SKB_FRAGS) 984 return -EMSGSIZE; 985 num_pages = get_user_pages_fast(base, size, 0, &page[i]); 986 if (num_pages != size) { 987 for (i = 0; i < num_pages; i++) 988 put_page(page[i]); 989 return -EFAULT; 990 } 991 truesize = size * PAGE_SIZE; 992 skb->data_len += len; 993 skb->len += len; 994 skb->truesize += truesize; 995 atomic_add(truesize, &skb->sk->sk_wmem_alloc); 996 while (len) { 997 int off = base & ~PAGE_MASK; 998 int size = min_t(int, len, PAGE_SIZE - off); 999 __skb_fill_page_desc(skb, i, page[i], off, size); 1000 skb_shinfo(skb)->nr_frags++; 1001 /* increase sk_wmem_alloc */ 1002 base += size; 1003 len -= size; 1004 i++; 1005 } 1006 offset = 0; 1007 ++from; 1008 } 1009 return 0; 1010 } 1011 1012 /* Get packet from user space buffer */ 1013 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1014 void *msg_control, const struct iovec *iv, 1015 size_t total_len, size_t count, int noblock) 1016 { 1017 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1018 struct sk_buff *skb; 1019 size_t len = total_len, align = NET_SKB_PAD; 1020 struct virtio_net_hdr gso = { 0 }; 1021 int offset = 0; 1022 int copylen; 1023 bool zerocopy = false; 1024 int err; 1025 1026 if (!(tun->flags & TUN_NO_PI)) { 1027 if ((len -= sizeof(pi)) > total_len) 1028 return -EINVAL; 1029 1030 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) 1031 return -EFAULT; 1032 offset += sizeof(pi); 1033 } 1034 1035 if (tun->flags & TUN_VNET_HDR) { 1036 if ((len -= tun->vnet_hdr_sz) > total_len) 1037 return -EINVAL; 1038 1039 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) 1040 return -EFAULT; 1041 1042 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1043 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) 1044 gso.hdr_len = gso.csum_start + gso.csum_offset + 2; 1045 1046 if (gso.hdr_len > len) 1047 return -EINVAL; 1048 offset += tun->vnet_hdr_sz; 1049 } 1050 1051 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { 1052 align += NET_IP_ALIGN; 1053 if (unlikely(len < ETH_HLEN || 1054 (gso.hdr_len && gso.hdr_len < ETH_HLEN))) 1055 return -EINVAL; 1056 } 1057 1058 if (msg_control) 1059 zerocopy = true; 1060 1061 if (zerocopy) { 1062 /* Userspace may produce vectors with count greater than 1063 * MAX_SKB_FRAGS, so we need to linearize parts of the skb 1064 * to let the rest of data to be fit in the frags. 1065 */ 1066 if (count > MAX_SKB_FRAGS) { 1067 copylen = iov_length(iv, count - MAX_SKB_FRAGS); 1068 if (copylen < offset) 1069 copylen = 0; 1070 else 1071 copylen -= offset; 1072 } else 1073 copylen = 0; 1074 /* There are 256 bytes to be copied in skb, so there is enough 1075 * room for skb expand head in case it is used. 1076 * The rest of the buffer is mapped from userspace. 1077 */ 1078 if (copylen < gso.hdr_len) 1079 copylen = gso.hdr_len; 1080 if (!copylen) 1081 copylen = GOODCOPY_LEN; 1082 } else 1083 copylen = len; 1084 1085 skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, noblock); 1086 if (IS_ERR(skb)) { 1087 if (PTR_ERR(skb) != -EAGAIN) 1088 tun->dev->stats.rx_dropped++; 1089 return PTR_ERR(skb); 1090 } 1091 1092 if (zerocopy) 1093 err = zerocopy_sg_from_iovec(skb, iv, offset, count); 1094 else 1095 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len); 1096 1097 if (err) { 1098 tun->dev->stats.rx_dropped++; 1099 kfree_skb(skb); 1100 return -EFAULT; 1101 } 1102 1103 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1104 if (!skb_partial_csum_set(skb, gso.csum_start, 1105 gso.csum_offset)) { 1106 tun->dev->stats.rx_frame_errors++; 1107 kfree_skb(skb); 1108 return -EINVAL; 1109 } 1110 } 1111 1112 switch (tun->flags & TUN_TYPE_MASK) { 1113 case TUN_TUN_DEV: 1114 if (tun->flags & TUN_NO_PI) { 1115 switch (skb->data[0] & 0xf0) { 1116 case 0x40: 1117 pi.proto = htons(ETH_P_IP); 1118 break; 1119 case 0x60: 1120 pi.proto = htons(ETH_P_IPV6); 1121 break; 1122 default: 1123 tun->dev->stats.rx_dropped++; 1124 kfree_skb(skb); 1125 return -EINVAL; 1126 } 1127 } 1128 1129 skb_reset_mac_header(skb); 1130 skb->protocol = pi.proto; 1131 skb->dev = tun->dev; 1132 break; 1133 case TUN_TAP_DEV: 1134 skb->protocol = eth_type_trans(skb, tun->dev); 1135 break; 1136 } 1137 1138 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1139 pr_debug("GSO!\n"); 1140 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1141 case VIRTIO_NET_HDR_GSO_TCPV4: 1142 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1143 break; 1144 case VIRTIO_NET_HDR_GSO_TCPV6: 1145 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1146 break; 1147 case VIRTIO_NET_HDR_GSO_UDP: 1148 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1149 break; 1150 default: 1151 tun->dev->stats.rx_frame_errors++; 1152 kfree_skb(skb); 1153 return -EINVAL; 1154 } 1155 1156 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1157 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1158 1159 skb_shinfo(skb)->gso_size = gso.gso_size; 1160 if (skb_shinfo(skb)->gso_size == 0) { 1161 tun->dev->stats.rx_frame_errors++; 1162 kfree_skb(skb); 1163 return -EINVAL; 1164 } 1165 1166 /* Header must be checked, and gso_segs computed. */ 1167 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1168 skb_shinfo(skb)->gso_segs = 0; 1169 } 1170 1171 /* copy skb_ubuf_info for callback when skb has no error */ 1172 if (zerocopy) { 1173 skb_shinfo(skb)->destructor_arg = msg_control; 1174 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1175 } 1176 1177 netif_rx_ni(skb); 1178 1179 tun->dev->stats.rx_packets++; 1180 tun->dev->stats.rx_bytes += len; 1181 1182 tun_flow_update(tun, skb, tfile->queue_index); 1183 return total_len; 1184 } 1185 1186 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 1187 unsigned long count, loff_t pos) 1188 { 1189 struct file *file = iocb->ki_filp; 1190 struct tun_struct *tun = tun_get(file); 1191 struct tun_file *tfile = file->private_data; 1192 ssize_t result; 1193 1194 if (!tun) 1195 return -EBADFD; 1196 1197 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count); 1198 1199 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count), 1200 count, file->f_flags & O_NONBLOCK); 1201 1202 tun_put(tun); 1203 return result; 1204 } 1205 1206 /* Put packet to the user space buffer */ 1207 static ssize_t tun_put_user(struct tun_struct *tun, 1208 struct tun_file *tfile, 1209 struct sk_buff *skb, 1210 const struct iovec *iv, int len) 1211 { 1212 struct tun_pi pi = { 0, skb->protocol }; 1213 ssize_t total = 0; 1214 1215 if (!(tun->flags & TUN_NO_PI)) { 1216 if ((len -= sizeof(pi)) < 0) 1217 return -EINVAL; 1218 1219 if (len < skb->len) { 1220 /* Packet will be striped */ 1221 pi.flags |= TUN_PKT_STRIP; 1222 } 1223 1224 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi))) 1225 return -EFAULT; 1226 total += sizeof(pi); 1227 } 1228 1229 if (tun->flags & TUN_VNET_HDR) { 1230 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1231 if ((len -= tun->vnet_hdr_sz) < 0) 1232 return -EINVAL; 1233 1234 if (skb_is_gso(skb)) { 1235 struct skb_shared_info *sinfo = skb_shinfo(skb); 1236 1237 /* This is a hint as to how much should be linear. */ 1238 gso.hdr_len = skb_headlen(skb); 1239 gso.gso_size = sinfo->gso_size; 1240 if (sinfo->gso_type & SKB_GSO_TCPV4) 1241 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1242 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1243 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1244 else if (sinfo->gso_type & SKB_GSO_UDP) 1245 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1246 else { 1247 pr_err("unexpected GSO type: " 1248 "0x%x, gso_size %d, hdr_len %d\n", 1249 sinfo->gso_type, gso.gso_size, 1250 gso.hdr_len); 1251 print_hex_dump(KERN_ERR, "tun: ", 1252 DUMP_PREFIX_NONE, 1253 16, 1, skb->head, 1254 min((int)gso.hdr_len, 64), true); 1255 WARN_ON_ONCE(1); 1256 return -EINVAL; 1257 } 1258 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1259 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1260 } else 1261 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1262 1263 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1264 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1265 gso.csum_start = skb_checksum_start_offset(skb); 1266 gso.csum_offset = skb->csum_offset; 1267 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1268 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1269 } /* else everything is zero */ 1270 1271 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, 1272 sizeof(gso)))) 1273 return -EFAULT; 1274 total += tun->vnet_hdr_sz; 1275 } 1276 1277 len = min_t(int, skb->len, len); 1278 1279 skb_copy_datagram_const_iovec(skb, 0, iv, total, len); 1280 total += skb->len; 1281 1282 tun->dev->stats.tx_packets++; 1283 tun->dev->stats.tx_bytes += len; 1284 1285 return total; 1286 } 1287 1288 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1289 struct kiocb *iocb, const struct iovec *iv, 1290 ssize_t len, int noblock) 1291 { 1292 DECLARE_WAITQUEUE(wait, current); 1293 struct sk_buff *skb; 1294 ssize_t ret = 0; 1295 1296 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1297 1298 if (unlikely(!noblock)) 1299 add_wait_queue(&tfile->wq.wait, &wait); 1300 while (len) { 1301 current->state = TASK_INTERRUPTIBLE; 1302 1303 /* Read frames from the queue */ 1304 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) { 1305 if (noblock) { 1306 ret = -EAGAIN; 1307 break; 1308 } 1309 if (signal_pending(current)) { 1310 ret = -ERESTARTSYS; 1311 break; 1312 } 1313 if (tun->dev->reg_state != NETREG_REGISTERED) { 1314 ret = -EIO; 1315 break; 1316 } 1317 1318 /* Nothing to read, let's sleep */ 1319 schedule(); 1320 continue; 1321 } 1322 netif_wake_subqueue(tun->dev, tfile->queue_index); 1323 1324 ret = tun_put_user(tun, tfile, skb, iv, len); 1325 kfree_skb(skb); 1326 break; 1327 } 1328 1329 current->state = TASK_RUNNING; 1330 if (unlikely(!noblock)) 1331 remove_wait_queue(&tfile->wq.wait, &wait); 1332 1333 return ret; 1334 } 1335 1336 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 1337 unsigned long count, loff_t pos) 1338 { 1339 struct file *file = iocb->ki_filp; 1340 struct tun_file *tfile = file->private_data; 1341 struct tun_struct *tun = __tun_get(tfile); 1342 ssize_t len, ret; 1343 1344 if (!tun) 1345 return -EBADFD; 1346 len = iov_length(iv, count); 1347 if (len < 0) { 1348 ret = -EINVAL; 1349 goto out; 1350 } 1351 1352 ret = tun_do_read(tun, tfile, iocb, iv, len, 1353 file->f_flags & O_NONBLOCK); 1354 ret = min_t(ssize_t, ret, len); 1355 out: 1356 tun_put(tun); 1357 return ret; 1358 } 1359 1360 static void tun_free_netdev(struct net_device *dev) 1361 { 1362 struct tun_struct *tun = netdev_priv(dev); 1363 1364 tun_flow_uninit(tun); 1365 free_netdev(dev); 1366 } 1367 1368 static void tun_setup(struct net_device *dev) 1369 { 1370 struct tun_struct *tun = netdev_priv(dev); 1371 1372 tun->owner = INVALID_UID; 1373 tun->group = INVALID_GID; 1374 1375 dev->ethtool_ops = &tun_ethtool_ops; 1376 dev->destructor = tun_free_netdev; 1377 } 1378 1379 /* Trivial set of netlink ops to allow deleting tun or tap 1380 * device with netlink. 1381 */ 1382 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1383 { 1384 return -EINVAL; 1385 } 1386 1387 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1388 .kind = DRV_NAME, 1389 .priv_size = sizeof(struct tun_struct), 1390 .setup = tun_setup, 1391 .validate = tun_validate, 1392 }; 1393 1394 static void tun_sock_write_space(struct sock *sk) 1395 { 1396 struct tun_file *tfile; 1397 wait_queue_head_t *wqueue; 1398 1399 if (!sock_writeable(sk)) 1400 return; 1401 1402 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1403 return; 1404 1405 wqueue = sk_sleep(sk); 1406 if (wqueue && waitqueue_active(wqueue)) 1407 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1408 POLLWRNORM | POLLWRBAND); 1409 1410 tfile = container_of(sk, struct tun_file, sk); 1411 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1412 } 1413 1414 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1415 struct msghdr *m, size_t total_len) 1416 { 1417 int ret; 1418 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1419 struct tun_struct *tun = __tun_get(tfile); 1420 1421 if (!tun) 1422 return -EBADFD; 1423 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len, 1424 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); 1425 tun_put(tun); 1426 return ret; 1427 } 1428 1429 1430 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1431 struct msghdr *m, size_t total_len, 1432 int flags) 1433 { 1434 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1435 struct tun_struct *tun = __tun_get(tfile); 1436 int ret; 1437 1438 if (!tun) 1439 return -EBADFD; 1440 1441 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) 1442 return -EINVAL; 1443 ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len, 1444 flags & MSG_DONTWAIT); 1445 if (ret > total_len) { 1446 m->msg_flags |= MSG_TRUNC; 1447 ret = flags & MSG_TRUNC ? ret : total_len; 1448 } 1449 tun_put(tun); 1450 return ret; 1451 } 1452 1453 static int tun_release(struct socket *sock) 1454 { 1455 if (sock->sk) 1456 sock_put(sock->sk); 1457 return 0; 1458 } 1459 1460 /* Ops structure to mimic raw sockets with tun */ 1461 static const struct proto_ops tun_socket_ops = { 1462 .sendmsg = tun_sendmsg, 1463 .recvmsg = tun_recvmsg, 1464 .release = tun_release, 1465 }; 1466 1467 static struct proto tun_proto = { 1468 .name = "tun", 1469 .owner = THIS_MODULE, 1470 .obj_size = sizeof(struct tun_file), 1471 }; 1472 1473 static int tun_flags(struct tun_struct *tun) 1474 { 1475 int flags = 0; 1476 1477 if (tun->flags & TUN_TUN_DEV) 1478 flags |= IFF_TUN; 1479 else 1480 flags |= IFF_TAP; 1481 1482 if (tun->flags & TUN_NO_PI) 1483 flags |= IFF_NO_PI; 1484 1485 if (tun->flags & TUN_ONE_QUEUE) 1486 flags |= IFF_ONE_QUEUE; 1487 1488 if (tun->flags & TUN_VNET_HDR) 1489 flags |= IFF_VNET_HDR; 1490 1491 if (tun->flags & TUN_TAP_MQ) 1492 flags |= IFF_MULTI_QUEUE; 1493 1494 return flags; 1495 } 1496 1497 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1498 char *buf) 1499 { 1500 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1501 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1502 } 1503 1504 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1505 char *buf) 1506 { 1507 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1508 return uid_valid(tun->owner)? 1509 sprintf(buf, "%u\n", 1510 from_kuid_munged(current_user_ns(), tun->owner)): 1511 sprintf(buf, "-1\n"); 1512 } 1513 1514 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1515 char *buf) 1516 { 1517 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1518 return gid_valid(tun->group) ? 1519 sprintf(buf, "%u\n", 1520 from_kgid_munged(current_user_ns(), tun->group)): 1521 sprintf(buf, "-1\n"); 1522 } 1523 1524 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1525 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1526 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1527 1528 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1529 { 1530 struct tun_struct *tun; 1531 struct tun_file *tfile = file->private_data; 1532 struct net_device *dev; 1533 int err; 1534 1535 dev = __dev_get_by_name(net, ifr->ifr_name); 1536 if (dev) { 1537 if (ifr->ifr_flags & IFF_TUN_EXCL) 1538 return -EBUSY; 1539 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1540 tun = netdev_priv(dev); 1541 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1542 tun = netdev_priv(dev); 1543 else 1544 return -EINVAL; 1545 1546 if (tun_not_capable(tun)) 1547 return -EPERM; 1548 err = security_tun_dev_attach(tfile->socket.sk); 1549 if (err < 0) 1550 return err; 1551 1552 err = tun_attach(tun, file); 1553 if (err < 0) 1554 return err; 1555 } 1556 else { 1557 char *name; 1558 unsigned long flags = 0; 1559 1560 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1561 return -EPERM; 1562 err = security_tun_dev_create(); 1563 if (err < 0) 1564 return err; 1565 1566 /* Set dev type */ 1567 if (ifr->ifr_flags & IFF_TUN) { 1568 /* TUN device */ 1569 flags |= TUN_TUN_DEV; 1570 name = "tun%d"; 1571 } else if (ifr->ifr_flags & IFF_TAP) { 1572 /* TAP device */ 1573 flags |= TUN_TAP_DEV; 1574 name = "tap%d"; 1575 } else 1576 return -EINVAL; 1577 1578 if (*ifr->ifr_name) 1579 name = ifr->ifr_name; 1580 1581 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1582 tun_setup, 1583 MAX_TAP_QUEUES, MAX_TAP_QUEUES); 1584 if (!dev) 1585 return -ENOMEM; 1586 1587 dev_net_set(dev, net); 1588 dev->rtnl_link_ops = &tun_link_ops; 1589 1590 tun = netdev_priv(dev); 1591 tun->dev = dev; 1592 tun->flags = flags; 1593 tun->txflt.count = 0; 1594 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1595 1596 tun->filter_attached = false; 1597 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1598 1599 spin_lock_init(&tun->lock); 1600 1601 security_tun_dev_post_create(&tfile->sk); 1602 1603 tun_net_init(dev); 1604 1605 if (tun_flow_init(tun)) 1606 goto err_free_dev; 1607 1608 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1609 TUN_USER_FEATURES; 1610 dev->features = dev->hw_features; 1611 1612 err = tun_attach(tun, file); 1613 if (err < 0) 1614 goto err_free_dev; 1615 1616 err = register_netdevice(tun->dev); 1617 if (err < 0) 1618 goto err_free_dev; 1619 1620 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1621 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1622 device_create_file(&tun->dev->dev, &dev_attr_group)) 1623 pr_err("Failed to create tun sysfs files\n"); 1624 1625 netif_carrier_on(tun->dev); 1626 } 1627 1628 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1629 1630 if (ifr->ifr_flags & IFF_NO_PI) 1631 tun->flags |= TUN_NO_PI; 1632 else 1633 tun->flags &= ~TUN_NO_PI; 1634 1635 if (ifr->ifr_flags & IFF_ONE_QUEUE) 1636 tun->flags |= TUN_ONE_QUEUE; 1637 else 1638 tun->flags &= ~TUN_ONE_QUEUE; 1639 1640 if (ifr->ifr_flags & IFF_VNET_HDR) 1641 tun->flags |= TUN_VNET_HDR; 1642 else 1643 tun->flags &= ~TUN_VNET_HDR; 1644 1645 if (ifr->ifr_flags & IFF_MULTI_QUEUE) 1646 tun->flags |= TUN_TAP_MQ; 1647 else 1648 tun->flags &= ~TUN_TAP_MQ; 1649 1650 /* Make sure persistent devices do not get stuck in 1651 * xoff state. 1652 */ 1653 if (netif_running(tun->dev)) 1654 netif_tx_wake_all_queues(tun->dev); 1655 1656 strcpy(ifr->ifr_name, tun->dev->name); 1657 return 0; 1658 1659 err_free_dev: 1660 free_netdev(dev); 1661 return err; 1662 } 1663 1664 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1665 struct ifreq *ifr) 1666 { 1667 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1668 1669 strcpy(ifr->ifr_name, tun->dev->name); 1670 1671 ifr->ifr_flags = tun_flags(tun); 1672 1673 } 1674 1675 /* This is like a cut-down ethtool ops, except done via tun fd so no 1676 * privs required. */ 1677 static int set_offload(struct tun_struct *tun, unsigned long arg) 1678 { 1679 netdev_features_t features = 0; 1680 1681 if (arg & TUN_F_CSUM) { 1682 features |= NETIF_F_HW_CSUM; 1683 arg &= ~TUN_F_CSUM; 1684 1685 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1686 if (arg & TUN_F_TSO_ECN) { 1687 features |= NETIF_F_TSO_ECN; 1688 arg &= ~TUN_F_TSO_ECN; 1689 } 1690 if (arg & TUN_F_TSO4) 1691 features |= NETIF_F_TSO; 1692 if (arg & TUN_F_TSO6) 1693 features |= NETIF_F_TSO6; 1694 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1695 } 1696 1697 if (arg & TUN_F_UFO) { 1698 features |= NETIF_F_UFO; 1699 arg &= ~TUN_F_UFO; 1700 } 1701 } 1702 1703 /* This gives the user a way to test for new features in future by 1704 * trying to set them. */ 1705 if (arg) 1706 return -EINVAL; 1707 1708 tun->set_features = features; 1709 netdev_update_features(tun->dev); 1710 1711 return 0; 1712 } 1713 1714 static void tun_detach_filter(struct tun_struct *tun, int n) 1715 { 1716 int i; 1717 struct tun_file *tfile; 1718 1719 for (i = 0; i < n; i++) { 1720 tfile = rcu_dereference_protected(tun->tfiles[i], 1721 lockdep_rtnl_is_held()); 1722 sk_detach_filter(tfile->socket.sk); 1723 } 1724 1725 tun->filter_attached = false; 1726 } 1727 1728 static int tun_attach_filter(struct tun_struct *tun) 1729 { 1730 int i, ret = 0; 1731 struct tun_file *tfile; 1732 1733 for (i = 0; i < tun->numqueues; i++) { 1734 tfile = rcu_dereference_protected(tun->tfiles[i], 1735 lockdep_rtnl_is_held()); 1736 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1737 if (ret) { 1738 tun_detach_filter(tun, i); 1739 return ret; 1740 } 1741 } 1742 1743 tun->filter_attached = true; 1744 return ret; 1745 } 1746 1747 static void tun_set_sndbuf(struct tun_struct *tun) 1748 { 1749 struct tun_file *tfile; 1750 int i; 1751 1752 for (i = 0; i < tun->numqueues; i++) { 1753 tfile = rcu_dereference_protected(tun->tfiles[i], 1754 lockdep_rtnl_is_held()); 1755 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1756 } 1757 } 1758 1759 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1760 { 1761 struct tun_file *tfile = file->private_data; 1762 struct tun_struct *tun; 1763 struct net_device *dev; 1764 int ret = 0; 1765 1766 rtnl_lock(); 1767 1768 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1769 dev = __dev_get_by_name(tfile->net, ifr->ifr_name); 1770 if (!dev) { 1771 ret = -EINVAL; 1772 goto unlock; 1773 } 1774 1775 tun = netdev_priv(dev); 1776 if (dev->netdev_ops != &tap_netdev_ops && 1777 dev->netdev_ops != &tun_netdev_ops) 1778 ret = -EINVAL; 1779 else if (tun_not_capable(tun)) 1780 ret = -EPERM; 1781 else 1782 ret = tun_attach(tun, file); 1783 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) 1784 __tun_detach(tfile, false); 1785 else 1786 ret = -EINVAL; 1787 1788 unlock: 1789 rtnl_unlock(); 1790 return ret; 1791 } 1792 1793 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1794 unsigned long arg, int ifreq_len) 1795 { 1796 struct tun_file *tfile = file->private_data; 1797 struct tun_struct *tun; 1798 void __user* argp = (void __user*)arg; 1799 struct ifreq ifr; 1800 kuid_t owner; 1801 kgid_t group; 1802 int sndbuf; 1803 int vnet_hdr_sz; 1804 int ret; 1805 1806 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1807 if (copy_from_user(&ifr, argp, ifreq_len)) 1808 return -EFAULT; 1809 } else { 1810 memset(&ifr, 0, sizeof(ifr)); 1811 } 1812 if (cmd == TUNGETFEATURES) { 1813 /* Currently this just means: "what IFF flags are valid?". 1814 * This is needed because we never checked for invalid flags on 1815 * TUNSETIFF. */ 1816 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | 1817 IFF_VNET_HDR | IFF_MULTI_QUEUE, 1818 (unsigned int __user*)argp); 1819 } else if (cmd == TUNSETQUEUE) 1820 return tun_set_queue(file, &ifr); 1821 1822 ret = 0; 1823 rtnl_lock(); 1824 1825 tun = __tun_get(tfile); 1826 if (cmd == TUNSETIFF && !tun) { 1827 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1828 1829 ret = tun_set_iff(tfile->net, file, &ifr); 1830 1831 if (ret) 1832 goto unlock; 1833 1834 if (copy_to_user(argp, &ifr, ifreq_len)) 1835 ret = -EFAULT; 1836 goto unlock; 1837 } 1838 1839 ret = -EBADFD; 1840 if (!tun) 1841 goto unlock; 1842 1843 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1844 1845 ret = 0; 1846 switch (cmd) { 1847 case TUNGETIFF: 1848 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1849 1850 if (copy_to_user(argp, &ifr, ifreq_len)) 1851 ret = -EFAULT; 1852 break; 1853 1854 case TUNSETNOCSUM: 1855 /* Disable/Enable checksum */ 1856 1857 /* [unimplemented] */ 1858 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1859 arg ? "disabled" : "enabled"); 1860 break; 1861 1862 case TUNSETPERSIST: 1863 /* Disable/Enable persist mode. Keep an extra reference to the 1864 * module to prevent the module being unprobed. 1865 */ 1866 if (arg) { 1867 tun->flags |= TUN_PERSIST; 1868 __module_get(THIS_MODULE); 1869 } else { 1870 tun->flags &= ~TUN_PERSIST; 1871 module_put(THIS_MODULE); 1872 } 1873 1874 tun_debug(KERN_INFO, tun, "persist %s\n", 1875 arg ? "enabled" : "disabled"); 1876 break; 1877 1878 case TUNSETOWNER: 1879 /* Set owner of the device */ 1880 owner = make_kuid(current_user_ns(), arg); 1881 if (!uid_valid(owner)) { 1882 ret = -EINVAL; 1883 break; 1884 } 1885 tun->owner = owner; 1886 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1887 from_kuid(&init_user_ns, tun->owner)); 1888 break; 1889 1890 case TUNSETGROUP: 1891 /* Set group of the device */ 1892 group = make_kgid(current_user_ns(), arg); 1893 if (!gid_valid(group)) { 1894 ret = -EINVAL; 1895 break; 1896 } 1897 tun->group = group; 1898 tun_debug(KERN_INFO, tun, "group set to %u\n", 1899 from_kgid(&init_user_ns, tun->group)); 1900 break; 1901 1902 case TUNSETLINK: 1903 /* Only allow setting the type when the interface is down */ 1904 if (tun->dev->flags & IFF_UP) { 1905 tun_debug(KERN_INFO, tun, 1906 "Linktype set failed because interface is up\n"); 1907 ret = -EBUSY; 1908 } else { 1909 tun->dev->type = (int) arg; 1910 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1911 tun->dev->type); 1912 ret = 0; 1913 } 1914 break; 1915 1916 #ifdef TUN_DEBUG 1917 case TUNSETDEBUG: 1918 tun->debug = arg; 1919 break; 1920 #endif 1921 case TUNSETOFFLOAD: 1922 ret = set_offload(tun, arg); 1923 break; 1924 1925 case TUNSETTXFILTER: 1926 /* Can be set only for TAPs */ 1927 ret = -EINVAL; 1928 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 1929 break; 1930 ret = update_filter(&tun->txflt, (void __user *)arg); 1931 break; 1932 1933 case SIOCGIFHWADDR: 1934 /* Get hw address */ 1935 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 1936 ifr.ifr_hwaddr.sa_family = tun->dev->type; 1937 if (copy_to_user(argp, &ifr, ifreq_len)) 1938 ret = -EFAULT; 1939 break; 1940 1941 case SIOCSIFHWADDR: 1942 /* Set hw address */ 1943 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 1944 ifr.ifr_hwaddr.sa_data); 1945 1946 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 1947 break; 1948 1949 case TUNGETSNDBUF: 1950 sndbuf = tfile->socket.sk->sk_sndbuf; 1951 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 1952 ret = -EFAULT; 1953 break; 1954 1955 case TUNSETSNDBUF: 1956 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 1957 ret = -EFAULT; 1958 break; 1959 } 1960 1961 tun->sndbuf = sndbuf; 1962 tun_set_sndbuf(tun); 1963 break; 1964 1965 case TUNGETVNETHDRSZ: 1966 vnet_hdr_sz = tun->vnet_hdr_sz; 1967 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 1968 ret = -EFAULT; 1969 break; 1970 1971 case TUNSETVNETHDRSZ: 1972 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 1973 ret = -EFAULT; 1974 break; 1975 } 1976 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 1977 ret = -EINVAL; 1978 break; 1979 } 1980 1981 tun->vnet_hdr_sz = vnet_hdr_sz; 1982 break; 1983 1984 case TUNATTACHFILTER: 1985 /* Can be set only for TAPs */ 1986 ret = -EINVAL; 1987 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 1988 break; 1989 ret = -EFAULT; 1990 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 1991 break; 1992 1993 ret = tun_attach_filter(tun); 1994 break; 1995 1996 case TUNDETACHFILTER: 1997 /* Can be set only for TAPs */ 1998 ret = -EINVAL; 1999 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 2000 break; 2001 ret = 0; 2002 tun_detach_filter(tun, tun->numqueues); 2003 break; 2004 2005 default: 2006 ret = -EINVAL; 2007 break; 2008 } 2009 2010 unlock: 2011 rtnl_unlock(); 2012 if (tun) 2013 tun_put(tun); 2014 return ret; 2015 } 2016 2017 static long tun_chr_ioctl(struct file *file, 2018 unsigned int cmd, unsigned long arg) 2019 { 2020 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2021 } 2022 2023 #ifdef CONFIG_COMPAT 2024 static long tun_chr_compat_ioctl(struct file *file, 2025 unsigned int cmd, unsigned long arg) 2026 { 2027 switch (cmd) { 2028 case TUNSETIFF: 2029 case TUNGETIFF: 2030 case TUNSETTXFILTER: 2031 case TUNGETSNDBUF: 2032 case TUNSETSNDBUF: 2033 case SIOCGIFHWADDR: 2034 case SIOCSIFHWADDR: 2035 arg = (unsigned long)compat_ptr(arg); 2036 break; 2037 default: 2038 arg = (compat_ulong_t)arg; 2039 break; 2040 } 2041 2042 /* 2043 * compat_ifreq is shorter than ifreq, so we must not access beyond 2044 * the end of that structure. All fields that are used in this 2045 * driver are compatible though, we don't need to convert the 2046 * contents. 2047 */ 2048 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2049 } 2050 #endif /* CONFIG_COMPAT */ 2051 2052 static int tun_chr_fasync(int fd, struct file *file, int on) 2053 { 2054 struct tun_file *tfile = file->private_data; 2055 int ret; 2056 2057 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2058 goto out; 2059 2060 if (on) { 2061 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2062 if (ret) 2063 goto out; 2064 tfile->flags |= TUN_FASYNC; 2065 } else 2066 tfile->flags &= ~TUN_FASYNC; 2067 ret = 0; 2068 out: 2069 return ret; 2070 } 2071 2072 static int tun_chr_open(struct inode *inode, struct file * file) 2073 { 2074 struct tun_file *tfile; 2075 2076 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2077 2078 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2079 &tun_proto); 2080 if (!tfile) 2081 return -ENOMEM; 2082 rcu_assign_pointer(tfile->tun, NULL); 2083 tfile->net = get_net(current->nsproxy->net_ns); 2084 tfile->flags = 0; 2085 2086 rcu_assign_pointer(tfile->socket.wq, &tfile->wq); 2087 init_waitqueue_head(&tfile->wq.wait); 2088 2089 tfile->socket.file = file; 2090 tfile->socket.ops = &tun_socket_ops; 2091 2092 sock_init_data(&tfile->socket, &tfile->sk); 2093 sk_change_net(&tfile->sk, tfile->net); 2094 2095 tfile->sk.sk_write_space = tun_sock_write_space; 2096 tfile->sk.sk_sndbuf = INT_MAX; 2097 2098 file->private_data = tfile; 2099 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2100 2101 return 0; 2102 } 2103 2104 static int tun_chr_close(struct inode *inode, struct file *file) 2105 { 2106 struct tun_file *tfile = file->private_data; 2107 struct net *net = tfile->net; 2108 2109 tun_detach(tfile, true); 2110 put_net(net); 2111 2112 return 0; 2113 } 2114 2115 static const struct file_operations tun_fops = { 2116 .owner = THIS_MODULE, 2117 .llseek = no_llseek, 2118 .read = do_sync_read, 2119 .aio_read = tun_chr_aio_read, 2120 .write = do_sync_write, 2121 .aio_write = tun_chr_aio_write, 2122 .poll = tun_chr_poll, 2123 .unlocked_ioctl = tun_chr_ioctl, 2124 #ifdef CONFIG_COMPAT 2125 .compat_ioctl = tun_chr_compat_ioctl, 2126 #endif 2127 .open = tun_chr_open, 2128 .release = tun_chr_close, 2129 .fasync = tun_chr_fasync 2130 }; 2131 2132 static struct miscdevice tun_miscdev = { 2133 .minor = TUN_MINOR, 2134 .name = "tun", 2135 .nodename = "net/tun", 2136 .fops = &tun_fops, 2137 }; 2138 2139 /* ethtool interface */ 2140 2141 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2142 { 2143 cmd->supported = 0; 2144 cmd->advertising = 0; 2145 ethtool_cmd_speed_set(cmd, SPEED_10); 2146 cmd->duplex = DUPLEX_FULL; 2147 cmd->port = PORT_TP; 2148 cmd->phy_address = 0; 2149 cmd->transceiver = XCVR_INTERNAL; 2150 cmd->autoneg = AUTONEG_DISABLE; 2151 cmd->maxtxpkt = 0; 2152 cmd->maxrxpkt = 0; 2153 return 0; 2154 } 2155 2156 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2157 { 2158 struct tun_struct *tun = netdev_priv(dev); 2159 2160 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2161 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2162 2163 switch (tun->flags & TUN_TYPE_MASK) { 2164 case TUN_TUN_DEV: 2165 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2166 break; 2167 case TUN_TAP_DEV: 2168 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2169 break; 2170 } 2171 } 2172 2173 static u32 tun_get_msglevel(struct net_device *dev) 2174 { 2175 #ifdef TUN_DEBUG 2176 struct tun_struct *tun = netdev_priv(dev); 2177 return tun->debug; 2178 #else 2179 return -EOPNOTSUPP; 2180 #endif 2181 } 2182 2183 static void tun_set_msglevel(struct net_device *dev, u32 value) 2184 { 2185 #ifdef TUN_DEBUG 2186 struct tun_struct *tun = netdev_priv(dev); 2187 tun->debug = value; 2188 #endif 2189 } 2190 2191 static const struct ethtool_ops tun_ethtool_ops = { 2192 .get_settings = tun_get_settings, 2193 .get_drvinfo = tun_get_drvinfo, 2194 .get_msglevel = tun_get_msglevel, 2195 .set_msglevel = tun_set_msglevel, 2196 .get_link = ethtool_op_get_link, 2197 }; 2198 2199 2200 static int __init tun_init(void) 2201 { 2202 int ret = 0; 2203 2204 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2205 pr_info("%s\n", DRV_COPYRIGHT); 2206 2207 ret = rtnl_link_register(&tun_link_ops); 2208 if (ret) { 2209 pr_err("Can't register link_ops\n"); 2210 goto err_linkops; 2211 } 2212 2213 ret = misc_register(&tun_miscdev); 2214 if (ret) { 2215 pr_err("Can't register misc device %d\n", TUN_MINOR); 2216 goto err_misc; 2217 } 2218 return 0; 2219 err_misc: 2220 rtnl_link_unregister(&tun_link_ops); 2221 err_linkops: 2222 return ret; 2223 } 2224 2225 static void tun_cleanup(void) 2226 { 2227 misc_deregister(&tun_miscdev); 2228 rtnl_link_unregister(&tun_link_ops); 2229 } 2230 2231 /* Get an underlying socket object from tun file. Returns error unless file is 2232 * attached to a device. The returned object works like a packet socket, it 2233 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2234 * holding a reference to the file for as long as the socket is in use. */ 2235 struct socket *tun_get_socket(struct file *file) 2236 { 2237 struct tun_file *tfile; 2238 if (file->f_op != &tun_fops) 2239 return ERR_PTR(-EINVAL); 2240 tfile = file->private_data; 2241 if (!tfile) 2242 return ERR_PTR(-EBADFD); 2243 return &tfile->socket; 2244 } 2245 EXPORT_SYMBOL_GPL(tun_get_socket); 2246 2247 module_init(tun_init); 2248 module_exit(tun_cleanup); 2249 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2250 MODULE_AUTHOR(DRV_COPYRIGHT); 2251 MODULE_LICENSE("GPL"); 2252 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2253 MODULE_ALIAS("devname:net/tun"); 2254