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