1 /* 2 * TUN - Universal TUN/TAP device driver. 3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $ 16 */ 17 18 /* 19 * Changes: 20 * 21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14 22 * Add TUNSETLINK ioctl to set the link encapsulation 23 * 24 * Mark Smith <markzzzsmith@yahoo.com.au> 25 * Use eth_random_addr() for tap MAC address. 26 * 27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20 28 * Fixes in packet dropping, queue length setting and queue wakeup. 29 * Increased default tx queue length. 30 * Added ethtool API. 31 * Minor cleanups 32 * 33 * Daniel Podlejski <underley@underley.eu.org> 34 * Modifications for 2.3.99-pre5 kernel. 35 */ 36 37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 38 39 #define DRV_NAME "tun" 40 #define DRV_VERSION "1.6" 41 #define DRV_DESCRIPTION "Universal TUN/TAP device driver" 42 #define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>" 43 44 #include <linux/module.h> 45 #include <linux/errno.h> 46 #include <linux/kernel.h> 47 #include <linux/major.h> 48 #include <linux/slab.h> 49 #include <linux/poll.h> 50 #include <linux/fcntl.h> 51 #include <linux/init.h> 52 #include <linux/skbuff.h> 53 #include <linux/netdevice.h> 54 #include <linux/etherdevice.h> 55 #include <linux/miscdevice.h> 56 #include <linux/ethtool.h> 57 #include <linux/rtnetlink.h> 58 #include <linux/compat.h> 59 #include <linux/if.h> 60 #include <linux/if_arp.h> 61 #include <linux/if_ether.h> 62 #include <linux/if_tun.h> 63 #include <linux/if_vlan.h> 64 #include <linux/crc32.h> 65 #include <linux/nsproxy.h> 66 #include <linux/virtio_net.h> 67 #include <linux/rcupdate.h> 68 #include <net/ipv6.h> 69 #include <net/net_namespace.h> 70 #include <net/netns/generic.h> 71 #include <net/rtnetlink.h> 72 #include <net/sock.h> 73 #include <linux/seq_file.h> 74 #include <linux/uio.h> 75 76 #include <asm/uaccess.h> 77 78 /* Uncomment to enable debugging */ 79 /* #define TUN_DEBUG 1 */ 80 81 #ifdef TUN_DEBUG 82 static int debug; 83 84 #define tun_debug(level, tun, fmt, args...) \ 85 do { \ 86 if (tun->debug) \ 87 netdev_printk(level, tun->dev, fmt, ##args); \ 88 } while (0) 89 #define DBG1(level, fmt, args...) \ 90 do { \ 91 if (debug == 2) \ 92 printk(level fmt, ##args); \ 93 } while (0) 94 #else 95 #define tun_debug(level, tun, fmt, args...) \ 96 do { \ 97 if (0) \ 98 netdev_printk(level, tun->dev, fmt, ##args); \ 99 } while (0) 100 #define DBG1(level, fmt, args...) \ 101 do { \ 102 if (0) \ 103 printk(level fmt, ##args); \ 104 } while (0) 105 #endif 106 107 /* TUN device flags */ 108 109 /* IFF_ATTACH_QUEUE is never stored in device flags, 110 * overload it to mean fasync when stored there. 111 */ 112 #define TUN_FASYNC IFF_ATTACH_QUEUE 113 114 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \ 115 IFF_VNET_LE | IFF_MULTI_QUEUE) 116 #define GOODCOPY_LEN 128 117 118 #define FLT_EXACT_COUNT 8 119 struct tap_filter { 120 unsigned int count; /* Number of addrs. Zero means disabled */ 121 u32 mask[2]; /* Mask of the hashed addrs */ 122 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 123 }; 124 125 /* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for 126 * the netdevice to be fit in one page. So we can make sure the success of 127 * memory allocation. TODO: increase the limit. */ 128 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES 129 #define MAX_TAP_FLOWS 4096 130 131 #define TUN_FLOW_EXPIRE (3 * HZ) 132 133 /* A tun_file connects an open character device to a tuntap netdevice. It 134 * also contains all socket related structures (except sock_fprog and tap_filter) 135 * to serve as one transmit queue for tuntap device. The sock_fprog and 136 * tap_filter were kept in tun_struct since they were used for filtering for the 137 * netdevice not for a specific queue (at least I didn't see the requirement for 138 * this). 139 * 140 * RCU usage: 141 * The tun_file and tun_struct are loosely coupled, the pointer from one to the 142 * other can only be read while rcu_read_lock or rtnl_lock is held. 143 */ 144 struct tun_file { 145 struct sock sk; 146 struct socket socket; 147 struct socket_wq wq; 148 struct tun_struct __rcu *tun; 149 struct net *net; 150 struct fasync_struct *fasync; 151 /* only used for fasnyc */ 152 unsigned int flags; 153 union { 154 u16 queue_index; 155 unsigned int ifindex; 156 }; 157 struct list_head next; 158 struct tun_struct *detached; 159 }; 160 161 struct tun_flow_entry { 162 struct hlist_node hash_link; 163 struct rcu_head rcu; 164 struct tun_struct *tun; 165 166 u32 rxhash; 167 u32 rps_rxhash; 168 int queue_index; 169 unsigned long updated; 170 }; 171 172 #define TUN_NUM_FLOW_ENTRIES 1024 173 174 /* Since the socket were moved to tun_file, to preserve the behavior of persist 175 * device, socket filter, sndbuf and vnet header size were restore when the 176 * file were attached to a persist device. 177 */ 178 struct tun_struct { 179 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES]; 180 unsigned int numqueues; 181 unsigned int flags; 182 kuid_t owner; 183 kgid_t group; 184 185 struct net_device *dev; 186 netdev_features_t set_features; 187 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 188 NETIF_F_TSO6) 189 190 int vnet_hdr_sz; 191 int sndbuf; 192 struct tap_filter txflt; 193 struct sock_fprog fprog; 194 /* protected by rtnl lock */ 195 bool filter_attached; 196 #ifdef TUN_DEBUG 197 int debug; 198 #endif 199 spinlock_t lock; 200 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; 201 struct timer_list flow_gc_timer; 202 unsigned long ageing_time; 203 unsigned int numdisabled; 204 struct list_head disabled; 205 void *security; 206 u32 flow_count; 207 }; 208 209 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) 210 { 211 return __virtio16_to_cpu(tun->flags & IFF_VNET_LE, val); 212 } 213 214 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val) 215 { 216 return __cpu_to_virtio16(tun->flags & IFF_VNET_LE, val); 217 } 218 219 static inline u32 tun_hashfn(u32 rxhash) 220 { 221 return rxhash & 0x3ff; 222 } 223 224 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) 225 { 226 struct tun_flow_entry *e; 227 228 hlist_for_each_entry_rcu(e, head, hash_link) { 229 if (e->rxhash == rxhash) 230 return e; 231 } 232 return NULL; 233 } 234 235 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, 236 struct hlist_head *head, 237 u32 rxhash, u16 queue_index) 238 { 239 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); 240 241 if (e) { 242 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", 243 rxhash, queue_index); 244 e->updated = jiffies; 245 e->rxhash = rxhash; 246 e->rps_rxhash = 0; 247 e->queue_index = queue_index; 248 e->tun = tun; 249 hlist_add_head_rcu(&e->hash_link, head); 250 ++tun->flow_count; 251 } 252 return e; 253 } 254 255 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) 256 { 257 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", 258 e->rxhash, e->queue_index); 259 sock_rps_reset_flow_hash(e->rps_rxhash); 260 hlist_del_rcu(&e->hash_link); 261 kfree_rcu(e, rcu); 262 --tun->flow_count; 263 } 264 265 static void tun_flow_flush(struct tun_struct *tun) 266 { 267 int i; 268 269 spin_lock_bh(&tun->lock); 270 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 271 struct tun_flow_entry *e; 272 struct hlist_node *n; 273 274 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 275 tun_flow_delete(tun, e); 276 } 277 spin_unlock_bh(&tun->lock); 278 } 279 280 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 281 { 282 int i; 283 284 spin_lock_bh(&tun->lock); 285 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 286 struct tun_flow_entry *e; 287 struct hlist_node *n; 288 289 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 290 if (e->queue_index == queue_index) 291 tun_flow_delete(tun, e); 292 } 293 } 294 spin_unlock_bh(&tun->lock); 295 } 296 297 static void tun_flow_cleanup(unsigned long data) 298 { 299 struct tun_struct *tun = (struct tun_struct *)data; 300 unsigned long delay = tun->ageing_time; 301 unsigned long next_timer = jiffies + delay; 302 unsigned long count = 0; 303 int i; 304 305 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 306 307 spin_lock_bh(&tun->lock); 308 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 309 struct tun_flow_entry *e; 310 struct hlist_node *n; 311 312 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 313 unsigned long this_timer; 314 count++; 315 this_timer = e->updated + delay; 316 if (time_before_eq(this_timer, jiffies)) 317 tun_flow_delete(tun, e); 318 else if (time_before(this_timer, next_timer)) 319 next_timer = this_timer; 320 } 321 } 322 323 if (count) 324 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 325 spin_unlock_bh(&tun->lock); 326 } 327 328 static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 329 struct tun_file *tfile) 330 { 331 struct hlist_head *head; 332 struct tun_flow_entry *e; 333 unsigned long delay = tun->ageing_time; 334 u16 queue_index = tfile->queue_index; 335 336 if (!rxhash) 337 return; 338 else 339 head = &tun->flows[tun_hashfn(rxhash)]; 340 341 rcu_read_lock(); 342 343 /* We may get a very small possibility of OOO during switching, not 344 * worth to optimize.*/ 345 if (tun->numqueues == 1 || tfile->detached) 346 goto unlock; 347 348 e = tun_flow_find(head, rxhash); 349 if (likely(e)) { 350 /* TODO: keep queueing to old queue until it's empty? */ 351 e->queue_index = queue_index; 352 e->updated = jiffies; 353 sock_rps_record_flow_hash(e->rps_rxhash); 354 } else { 355 spin_lock_bh(&tun->lock); 356 if (!tun_flow_find(head, rxhash) && 357 tun->flow_count < MAX_TAP_FLOWS) 358 tun_flow_create(tun, head, rxhash, queue_index); 359 360 if (!timer_pending(&tun->flow_gc_timer)) 361 mod_timer(&tun->flow_gc_timer, 362 round_jiffies_up(jiffies + delay)); 363 spin_unlock_bh(&tun->lock); 364 } 365 366 unlock: 367 rcu_read_unlock(); 368 } 369 370 /** 371 * Save the hash received in the stack receive path and update the 372 * flow_hash table accordingly. 373 */ 374 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 375 { 376 if (unlikely(e->rps_rxhash != hash)) { 377 sock_rps_reset_flow_hash(e->rps_rxhash); 378 e->rps_rxhash = hash; 379 } 380 } 381 382 /* We try to identify a flow through its rxhash first. The reason that 383 * we do not check rxq no. is because some cards(e.g 82599), chooses 384 * the rxq based on the txq where the last packet of the flow comes. As 385 * the userspace application move between processors, we may get a 386 * different rxq no. here. If we could not get rxhash, then we would 387 * hope the rxq no. may help here. 388 */ 389 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, 390 void *accel_priv, select_queue_fallback_t fallback) 391 { 392 struct tun_struct *tun = netdev_priv(dev); 393 struct tun_flow_entry *e; 394 u32 txq = 0; 395 u32 numqueues = 0; 396 397 rcu_read_lock(); 398 numqueues = ACCESS_ONCE(tun->numqueues); 399 400 txq = skb_get_hash(skb); 401 if (txq) { 402 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 403 if (e) { 404 tun_flow_save_rps_rxhash(e, txq); 405 txq = e->queue_index; 406 } else 407 /* use multiply and shift instead of expensive divide */ 408 txq = ((u64)txq * numqueues) >> 32; 409 } else if (likely(skb_rx_queue_recorded(skb))) { 410 txq = skb_get_rx_queue(skb); 411 while (unlikely(txq >= numqueues)) 412 txq -= numqueues; 413 } 414 415 rcu_read_unlock(); 416 return txq; 417 } 418 419 static inline bool tun_not_capable(struct tun_struct *tun) 420 { 421 const struct cred *cred = current_cred(); 422 struct net *net = dev_net(tun->dev); 423 424 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 425 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 426 !ns_capable(net->user_ns, CAP_NET_ADMIN); 427 } 428 429 static void tun_set_real_num_queues(struct tun_struct *tun) 430 { 431 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 432 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 433 } 434 435 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 436 { 437 tfile->detached = tun; 438 list_add_tail(&tfile->next, &tun->disabled); 439 ++tun->numdisabled; 440 } 441 442 static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 443 { 444 struct tun_struct *tun = tfile->detached; 445 446 tfile->detached = NULL; 447 list_del_init(&tfile->next); 448 --tun->numdisabled; 449 return tun; 450 } 451 452 static void tun_queue_purge(struct tun_file *tfile) 453 { 454 skb_queue_purge(&tfile->sk.sk_receive_queue); 455 skb_queue_purge(&tfile->sk.sk_error_queue); 456 } 457 458 static void __tun_detach(struct tun_file *tfile, bool clean) 459 { 460 struct tun_file *ntfile; 461 struct tun_struct *tun; 462 463 tun = rtnl_dereference(tfile->tun); 464 465 if (tun && !tfile->detached) { 466 u16 index = tfile->queue_index; 467 BUG_ON(index >= tun->numqueues); 468 469 rcu_assign_pointer(tun->tfiles[index], 470 tun->tfiles[tun->numqueues - 1]); 471 ntfile = rtnl_dereference(tun->tfiles[index]); 472 ntfile->queue_index = index; 473 474 --tun->numqueues; 475 if (clean) { 476 RCU_INIT_POINTER(tfile->tun, NULL); 477 sock_put(&tfile->sk); 478 } else 479 tun_disable_queue(tun, tfile); 480 481 synchronize_net(); 482 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 483 /* Drop read queue */ 484 tun_queue_purge(tfile); 485 tun_set_real_num_queues(tun); 486 } else if (tfile->detached && clean) { 487 tun = tun_enable_queue(tfile); 488 sock_put(&tfile->sk); 489 } 490 491 if (clean) { 492 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 493 netif_carrier_off(tun->dev); 494 495 if (!(tun->flags & IFF_PERSIST) && 496 tun->dev->reg_state == NETREG_REGISTERED) 497 unregister_netdevice(tun->dev); 498 } 499 500 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 501 &tfile->socket.flags)); 502 sk_release_kernel(&tfile->sk); 503 } 504 } 505 506 static void tun_detach(struct tun_file *tfile, bool clean) 507 { 508 rtnl_lock(); 509 __tun_detach(tfile, clean); 510 rtnl_unlock(); 511 } 512 513 static void tun_detach_all(struct net_device *dev) 514 { 515 struct tun_struct *tun = netdev_priv(dev); 516 struct tun_file *tfile, *tmp; 517 int i, n = tun->numqueues; 518 519 for (i = 0; i < n; i++) { 520 tfile = rtnl_dereference(tun->tfiles[i]); 521 BUG_ON(!tfile); 522 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 523 RCU_INIT_POINTER(tfile->tun, NULL); 524 --tun->numqueues; 525 } 526 list_for_each_entry(tfile, &tun->disabled, next) { 527 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 528 RCU_INIT_POINTER(tfile->tun, NULL); 529 } 530 BUG_ON(tun->numqueues != 0); 531 532 synchronize_net(); 533 for (i = 0; i < n; i++) { 534 tfile = rtnl_dereference(tun->tfiles[i]); 535 /* Drop read queue */ 536 tun_queue_purge(tfile); 537 sock_put(&tfile->sk); 538 } 539 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 540 tun_enable_queue(tfile); 541 tun_queue_purge(tfile); 542 sock_put(&tfile->sk); 543 } 544 BUG_ON(tun->numdisabled != 0); 545 546 if (tun->flags & IFF_PERSIST) 547 module_put(THIS_MODULE); 548 } 549 550 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) 551 { 552 struct tun_file *tfile = file->private_data; 553 int err; 554 555 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 556 if (err < 0) 557 goto out; 558 559 err = -EINVAL; 560 if (rtnl_dereference(tfile->tun) && !tfile->detached) 561 goto out; 562 563 err = -EBUSY; 564 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1) 565 goto out; 566 567 err = -E2BIG; 568 if (!tfile->detached && 569 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 570 goto out; 571 572 err = 0; 573 574 /* Re-attach the filter to persist device */ 575 if (!skip_filter && (tun->filter_attached == true)) { 576 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 577 if (!err) 578 goto out; 579 } 580 tfile->queue_index = tun->numqueues; 581 rcu_assign_pointer(tfile->tun, tun); 582 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 583 tun->numqueues++; 584 585 if (tfile->detached) 586 tun_enable_queue(tfile); 587 else 588 sock_hold(&tfile->sk); 589 590 tun_set_real_num_queues(tun); 591 592 /* device is allowed to go away first, so no need to hold extra 593 * refcnt. 594 */ 595 596 out: 597 return err; 598 } 599 600 static struct tun_struct *__tun_get(struct tun_file *tfile) 601 { 602 struct tun_struct *tun; 603 604 rcu_read_lock(); 605 tun = rcu_dereference(tfile->tun); 606 if (tun) 607 dev_hold(tun->dev); 608 rcu_read_unlock(); 609 610 return tun; 611 } 612 613 static struct tun_struct *tun_get(struct file *file) 614 { 615 return __tun_get(file->private_data); 616 } 617 618 static void tun_put(struct tun_struct *tun) 619 { 620 dev_put(tun->dev); 621 } 622 623 /* TAP filtering */ 624 static void addr_hash_set(u32 *mask, const u8 *addr) 625 { 626 int n = ether_crc(ETH_ALEN, addr) >> 26; 627 mask[n >> 5] |= (1 << (n & 31)); 628 } 629 630 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 631 { 632 int n = ether_crc(ETH_ALEN, addr) >> 26; 633 return mask[n >> 5] & (1 << (n & 31)); 634 } 635 636 static int update_filter(struct tap_filter *filter, void __user *arg) 637 { 638 struct { u8 u[ETH_ALEN]; } *addr; 639 struct tun_filter uf; 640 int err, alen, n, nexact; 641 642 if (copy_from_user(&uf, arg, sizeof(uf))) 643 return -EFAULT; 644 645 if (!uf.count) { 646 /* Disabled */ 647 filter->count = 0; 648 return 0; 649 } 650 651 alen = ETH_ALEN * uf.count; 652 addr = kmalloc(alen, GFP_KERNEL); 653 if (!addr) 654 return -ENOMEM; 655 656 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 657 err = -EFAULT; 658 goto done; 659 } 660 661 /* The filter is updated without holding any locks. Which is 662 * perfectly safe. We disable it first and in the worst 663 * case we'll accept a few undesired packets. */ 664 filter->count = 0; 665 wmb(); 666 667 /* Use first set of addresses as an exact filter */ 668 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 669 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 670 671 nexact = n; 672 673 /* Remaining multicast addresses are hashed, 674 * unicast will leave the filter disabled. */ 675 memset(filter->mask, 0, sizeof(filter->mask)); 676 for (; n < uf.count; n++) { 677 if (!is_multicast_ether_addr(addr[n].u)) { 678 err = 0; /* no filter */ 679 goto done; 680 } 681 addr_hash_set(filter->mask, addr[n].u); 682 } 683 684 /* For ALLMULTI just set the mask to all ones. 685 * This overrides the mask populated above. */ 686 if ((uf.flags & TUN_FLT_ALLMULTI)) 687 memset(filter->mask, ~0, sizeof(filter->mask)); 688 689 /* Now enable the filter */ 690 wmb(); 691 filter->count = nexact; 692 693 /* Return the number of exact filters */ 694 err = nexact; 695 696 done: 697 kfree(addr); 698 return err; 699 } 700 701 /* Returns: 0 - drop, !=0 - accept */ 702 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 703 { 704 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 705 * at this point. */ 706 struct ethhdr *eh = (struct ethhdr *) skb->data; 707 int i; 708 709 /* Exact match */ 710 for (i = 0; i < filter->count; i++) 711 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 712 return 1; 713 714 /* Inexact match (multicast only) */ 715 if (is_multicast_ether_addr(eh->h_dest)) 716 return addr_hash_test(filter->mask, eh->h_dest); 717 718 return 0; 719 } 720 721 /* 722 * Checks whether the packet is accepted or not. 723 * Returns: 0 - drop, !=0 - accept 724 */ 725 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 726 { 727 if (!filter->count) 728 return 1; 729 730 return run_filter(filter, skb); 731 } 732 733 /* Network device part of the driver */ 734 735 static const struct ethtool_ops tun_ethtool_ops; 736 737 /* Net device detach from fd. */ 738 static void tun_net_uninit(struct net_device *dev) 739 { 740 tun_detach_all(dev); 741 } 742 743 /* Net device open. */ 744 static int tun_net_open(struct net_device *dev) 745 { 746 netif_tx_start_all_queues(dev); 747 return 0; 748 } 749 750 /* Net device close. */ 751 static int tun_net_close(struct net_device *dev) 752 { 753 netif_tx_stop_all_queues(dev); 754 return 0; 755 } 756 757 /* Net device start xmit */ 758 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 759 { 760 struct tun_struct *tun = netdev_priv(dev); 761 int txq = skb->queue_mapping; 762 struct tun_file *tfile; 763 u32 numqueues = 0; 764 765 rcu_read_lock(); 766 tfile = rcu_dereference(tun->tfiles[txq]); 767 numqueues = ACCESS_ONCE(tun->numqueues); 768 769 /* Drop packet if interface is not attached */ 770 if (txq >= numqueues) 771 goto drop; 772 773 if (numqueues == 1) { 774 /* Select queue was not called for the skbuff, so we extract the 775 * RPS hash and save it into the flow_table here. 776 */ 777 __u32 rxhash; 778 779 rxhash = skb_get_hash(skb); 780 if (rxhash) { 781 struct tun_flow_entry *e; 782 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], 783 rxhash); 784 if (e) 785 tun_flow_save_rps_rxhash(e, rxhash); 786 } 787 } 788 789 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 790 791 BUG_ON(!tfile); 792 793 /* Drop if the filter does not like it. 794 * This is a noop if the filter is disabled. 795 * Filter can be enabled only for the TAP devices. */ 796 if (!check_filter(&tun->txflt, skb)) 797 goto drop; 798 799 if (tfile->socket.sk->sk_filter && 800 sk_filter(tfile->socket.sk, skb)) 801 goto drop; 802 803 /* Limit the number of packets queued by dividing txq length with the 804 * number of queues. 805 */ 806 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues 807 >= dev->tx_queue_len) 808 goto drop; 809 810 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 811 goto drop; 812 813 if (skb->sk) { 814 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags); 815 sw_tx_timestamp(skb); 816 } 817 818 /* Orphan the skb - required as we might hang on to it 819 * for indefinite time. 820 */ 821 skb_orphan(skb); 822 823 nf_reset(skb); 824 825 /* Enqueue packet */ 826 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 827 828 /* Notify and wake up reader process */ 829 if (tfile->flags & TUN_FASYNC) 830 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 831 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 832 833 rcu_read_unlock(); 834 return NETDEV_TX_OK; 835 836 drop: 837 dev->stats.tx_dropped++; 838 skb_tx_error(skb); 839 kfree_skb(skb); 840 rcu_read_unlock(); 841 return NET_XMIT_DROP; 842 } 843 844 static void tun_net_mclist(struct net_device *dev) 845 { 846 /* 847 * This callback is supposed to deal with mc filter in 848 * _rx_ path and has nothing to do with the _tx_ path. 849 * In rx path we always accept everything userspace gives us. 850 */ 851 } 852 853 #define MIN_MTU 68 854 #define MAX_MTU 65535 855 856 static int 857 tun_net_change_mtu(struct net_device *dev, int new_mtu) 858 { 859 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 860 return -EINVAL; 861 dev->mtu = new_mtu; 862 return 0; 863 } 864 865 static netdev_features_t tun_net_fix_features(struct net_device *dev, 866 netdev_features_t features) 867 { 868 struct tun_struct *tun = netdev_priv(dev); 869 870 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 871 } 872 #ifdef CONFIG_NET_POLL_CONTROLLER 873 static void tun_poll_controller(struct net_device *dev) 874 { 875 /* 876 * Tun only receives frames when: 877 * 1) the char device endpoint gets data from user space 878 * 2) the tun socket gets a sendmsg call from user space 879 * Since both of those are synchronous operations, we are guaranteed 880 * never to have pending data when we poll for it 881 * so there is nothing to do here but return. 882 * We need this though so netpoll recognizes us as an interface that 883 * supports polling, which enables bridge devices in virt setups to 884 * still use netconsole 885 */ 886 return; 887 } 888 #endif 889 static const struct net_device_ops tun_netdev_ops = { 890 .ndo_uninit = tun_net_uninit, 891 .ndo_open = tun_net_open, 892 .ndo_stop = tun_net_close, 893 .ndo_start_xmit = tun_net_xmit, 894 .ndo_change_mtu = tun_net_change_mtu, 895 .ndo_fix_features = tun_net_fix_features, 896 .ndo_select_queue = tun_select_queue, 897 #ifdef CONFIG_NET_POLL_CONTROLLER 898 .ndo_poll_controller = tun_poll_controller, 899 #endif 900 }; 901 902 static const struct net_device_ops tap_netdev_ops = { 903 .ndo_uninit = tun_net_uninit, 904 .ndo_open = tun_net_open, 905 .ndo_stop = tun_net_close, 906 .ndo_start_xmit = tun_net_xmit, 907 .ndo_change_mtu = tun_net_change_mtu, 908 .ndo_fix_features = tun_net_fix_features, 909 .ndo_set_rx_mode = tun_net_mclist, 910 .ndo_set_mac_address = eth_mac_addr, 911 .ndo_validate_addr = eth_validate_addr, 912 .ndo_select_queue = tun_select_queue, 913 #ifdef CONFIG_NET_POLL_CONTROLLER 914 .ndo_poll_controller = tun_poll_controller, 915 #endif 916 }; 917 918 static void tun_flow_init(struct tun_struct *tun) 919 { 920 int i; 921 922 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 923 INIT_HLIST_HEAD(&tun->flows[i]); 924 925 tun->ageing_time = TUN_FLOW_EXPIRE; 926 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 927 mod_timer(&tun->flow_gc_timer, 928 round_jiffies_up(jiffies + tun->ageing_time)); 929 } 930 931 static void tun_flow_uninit(struct tun_struct *tun) 932 { 933 del_timer_sync(&tun->flow_gc_timer); 934 tun_flow_flush(tun); 935 } 936 937 /* Initialize net device. */ 938 static void tun_net_init(struct net_device *dev) 939 { 940 struct tun_struct *tun = netdev_priv(dev); 941 942 switch (tun->flags & TUN_TYPE_MASK) { 943 case IFF_TUN: 944 dev->netdev_ops = &tun_netdev_ops; 945 946 /* Point-to-Point TUN Device */ 947 dev->hard_header_len = 0; 948 dev->addr_len = 0; 949 dev->mtu = 1500; 950 951 /* Zero header length */ 952 dev->type = ARPHRD_NONE; 953 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 954 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 955 break; 956 957 case IFF_TAP: 958 dev->netdev_ops = &tap_netdev_ops; 959 /* Ethernet TAP Device */ 960 ether_setup(dev); 961 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 962 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 963 964 eth_hw_addr_random(dev); 965 966 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 967 break; 968 } 969 } 970 971 /* Character device part */ 972 973 /* Poll */ 974 static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 975 { 976 struct tun_file *tfile = file->private_data; 977 struct tun_struct *tun = __tun_get(tfile); 978 struct sock *sk; 979 unsigned int mask = 0; 980 981 if (!tun) 982 return POLLERR; 983 984 sk = tfile->socket.sk; 985 986 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 987 988 poll_wait(file, sk_sleep(sk), wait); 989 990 if (!skb_queue_empty(&sk->sk_receive_queue)) 991 mask |= POLLIN | POLLRDNORM; 992 993 if (sock_writeable(sk) || 994 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 995 sock_writeable(sk))) 996 mask |= POLLOUT | POLLWRNORM; 997 998 if (tun->dev->reg_state != NETREG_REGISTERED) 999 mask = POLLERR; 1000 1001 tun_put(tun); 1002 return mask; 1003 } 1004 1005 /* prepad is the amount to reserve at front. len is length after that. 1006 * linear is a hint as to how much to copy (usually headers). */ 1007 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 1008 size_t prepad, size_t len, 1009 size_t linear, int noblock) 1010 { 1011 struct sock *sk = tfile->socket.sk; 1012 struct sk_buff *skb; 1013 int err; 1014 1015 /* Under a page? Don't bother with paged skb. */ 1016 if (prepad + len < PAGE_SIZE || !linear) 1017 linear = len; 1018 1019 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 1020 &err, 0); 1021 if (!skb) 1022 return ERR_PTR(err); 1023 1024 skb_reserve(skb, prepad); 1025 skb_put(skb, linear); 1026 skb->data_len = len - linear; 1027 skb->len += len - linear; 1028 1029 return skb; 1030 } 1031 1032 /* Get packet from user space buffer */ 1033 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1034 void *msg_control, struct iov_iter *from, 1035 int noblock) 1036 { 1037 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1038 struct sk_buff *skb; 1039 size_t total_len = iov_iter_count(from); 1040 size_t len = total_len, align = NET_SKB_PAD, linear; 1041 struct virtio_net_hdr gso = { 0 }; 1042 int good_linear; 1043 int copylen; 1044 bool zerocopy = false; 1045 int err; 1046 u32 rxhash; 1047 ssize_t n; 1048 1049 if (!(tun->flags & IFF_NO_PI)) { 1050 if (len < sizeof(pi)) 1051 return -EINVAL; 1052 len -= sizeof(pi); 1053 1054 n = copy_from_iter(&pi, sizeof(pi), from); 1055 if (n != sizeof(pi)) 1056 return -EFAULT; 1057 } 1058 1059 if (tun->flags & IFF_VNET_HDR) { 1060 if (len < tun->vnet_hdr_sz) 1061 return -EINVAL; 1062 len -= tun->vnet_hdr_sz; 1063 1064 n = copy_from_iter(&gso, sizeof(gso), from); 1065 if (n != sizeof(gso)) 1066 return -EFAULT; 1067 1068 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1069 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len)) 1070 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2); 1071 1072 if (tun16_to_cpu(tun, gso.hdr_len) > len) 1073 return -EINVAL; 1074 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso)); 1075 } 1076 1077 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) { 1078 align += NET_IP_ALIGN; 1079 if (unlikely(len < ETH_HLEN || 1080 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN))) 1081 return -EINVAL; 1082 } 1083 1084 good_linear = SKB_MAX_HEAD(align); 1085 1086 if (msg_control) { 1087 struct iov_iter i = *from; 1088 1089 /* There are 256 bytes to be copied in skb, so there is 1090 * enough room for skb expand head in case it is used. 1091 * The rest of the buffer is mapped from userspace. 1092 */ 1093 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN; 1094 if (copylen > good_linear) 1095 copylen = good_linear; 1096 linear = copylen; 1097 iov_iter_advance(&i, copylen); 1098 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS) 1099 zerocopy = true; 1100 } 1101 1102 if (!zerocopy) { 1103 copylen = len; 1104 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear) 1105 linear = good_linear; 1106 else 1107 linear = tun16_to_cpu(tun, gso.hdr_len); 1108 } 1109 1110 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1111 if (IS_ERR(skb)) { 1112 if (PTR_ERR(skb) != -EAGAIN) 1113 tun->dev->stats.rx_dropped++; 1114 return PTR_ERR(skb); 1115 } 1116 1117 if (zerocopy) 1118 err = zerocopy_sg_from_iter(skb, from); 1119 else { 1120 err = skb_copy_datagram_from_iter(skb, 0, from, len); 1121 if (!err && msg_control) { 1122 struct ubuf_info *uarg = msg_control; 1123 uarg->callback(uarg, false); 1124 } 1125 } 1126 1127 if (err) { 1128 tun->dev->stats.rx_dropped++; 1129 kfree_skb(skb); 1130 return -EFAULT; 1131 } 1132 1133 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1134 if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start), 1135 tun16_to_cpu(tun, gso.csum_offset))) { 1136 tun->dev->stats.rx_frame_errors++; 1137 kfree_skb(skb); 1138 return -EINVAL; 1139 } 1140 } 1141 1142 switch (tun->flags & TUN_TYPE_MASK) { 1143 case IFF_TUN: 1144 if (tun->flags & IFF_NO_PI) { 1145 switch (skb->data[0] & 0xf0) { 1146 case 0x40: 1147 pi.proto = htons(ETH_P_IP); 1148 break; 1149 case 0x60: 1150 pi.proto = htons(ETH_P_IPV6); 1151 break; 1152 default: 1153 tun->dev->stats.rx_dropped++; 1154 kfree_skb(skb); 1155 return -EINVAL; 1156 } 1157 } 1158 1159 skb_reset_mac_header(skb); 1160 skb->protocol = pi.proto; 1161 skb->dev = tun->dev; 1162 break; 1163 case IFF_TAP: 1164 skb->protocol = eth_type_trans(skb, tun->dev); 1165 break; 1166 } 1167 1168 skb_reset_network_header(skb); 1169 1170 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1171 pr_debug("GSO!\n"); 1172 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1173 case VIRTIO_NET_HDR_GSO_TCPV4: 1174 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1175 break; 1176 case VIRTIO_NET_HDR_GSO_TCPV6: 1177 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1178 break; 1179 case VIRTIO_NET_HDR_GSO_UDP: 1180 { 1181 static bool warned; 1182 1183 if (!warned) { 1184 warned = true; 1185 netdev_warn(tun->dev, 1186 "%s: using disabled UFO feature; please fix this program\n", 1187 current->comm); 1188 } 1189 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1190 if (skb->protocol == htons(ETH_P_IPV6)) 1191 ipv6_proxy_select_ident(skb); 1192 break; 1193 } 1194 default: 1195 tun->dev->stats.rx_frame_errors++; 1196 kfree_skb(skb); 1197 return -EINVAL; 1198 } 1199 1200 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1201 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1202 1203 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size); 1204 if (skb_shinfo(skb)->gso_size == 0) { 1205 tun->dev->stats.rx_frame_errors++; 1206 kfree_skb(skb); 1207 return -EINVAL; 1208 } 1209 1210 /* Header must be checked, and gso_segs computed. */ 1211 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1212 skb_shinfo(skb)->gso_segs = 0; 1213 } 1214 1215 /* copy skb_ubuf_info for callback when skb has no error */ 1216 if (zerocopy) { 1217 skb_shinfo(skb)->destructor_arg = msg_control; 1218 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1219 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1220 } 1221 1222 skb_probe_transport_header(skb, 0); 1223 1224 rxhash = skb_get_hash(skb); 1225 netif_rx_ni(skb); 1226 1227 tun->dev->stats.rx_packets++; 1228 tun->dev->stats.rx_bytes += len; 1229 1230 tun_flow_update(tun, rxhash, tfile); 1231 return total_len; 1232 } 1233 1234 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from) 1235 { 1236 struct file *file = iocb->ki_filp; 1237 struct tun_struct *tun = tun_get(file); 1238 struct tun_file *tfile = file->private_data; 1239 ssize_t result; 1240 1241 if (!tun) 1242 return -EBADFD; 1243 1244 result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK); 1245 1246 tun_put(tun); 1247 return result; 1248 } 1249 1250 /* Put packet to the user space buffer */ 1251 static ssize_t tun_put_user(struct tun_struct *tun, 1252 struct tun_file *tfile, 1253 struct sk_buff *skb, 1254 struct iov_iter *iter) 1255 { 1256 struct tun_pi pi = { 0, skb->protocol }; 1257 ssize_t total; 1258 int vlan_offset = 0; 1259 int vlan_hlen = 0; 1260 int vnet_hdr_sz = 0; 1261 1262 if (vlan_tx_tag_present(skb)) 1263 vlan_hlen = VLAN_HLEN; 1264 1265 if (tun->flags & IFF_VNET_HDR) 1266 vnet_hdr_sz = tun->vnet_hdr_sz; 1267 1268 total = skb->len + vlan_hlen + vnet_hdr_sz; 1269 1270 if (!(tun->flags & IFF_NO_PI)) { 1271 if (iov_iter_count(iter) < sizeof(pi)) 1272 return -EINVAL; 1273 1274 total += sizeof(pi); 1275 if (iov_iter_count(iter) < total) { 1276 /* Packet will be striped */ 1277 pi.flags |= TUN_PKT_STRIP; 1278 } 1279 1280 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi)) 1281 return -EFAULT; 1282 } 1283 1284 if (vnet_hdr_sz) { 1285 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1286 if (iov_iter_count(iter) < vnet_hdr_sz) 1287 return -EINVAL; 1288 1289 if (skb_is_gso(skb)) { 1290 struct skb_shared_info *sinfo = skb_shinfo(skb); 1291 1292 /* This is a hint as to how much should be linear. */ 1293 gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb)); 1294 gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size); 1295 if (sinfo->gso_type & SKB_GSO_TCPV4) 1296 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1297 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1298 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1299 else { 1300 pr_err("unexpected GSO type: " 1301 "0x%x, gso_size %d, hdr_len %d\n", 1302 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size), 1303 tun16_to_cpu(tun, gso.hdr_len)); 1304 print_hex_dump(KERN_ERR, "tun: ", 1305 DUMP_PREFIX_NONE, 1306 16, 1, skb->head, 1307 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true); 1308 WARN_ON_ONCE(1); 1309 return -EINVAL; 1310 } 1311 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1312 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1313 } else 1314 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1315 1316 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1317 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1318 gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) + 1319 vlan_hlen); 1320 gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset); 1321 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1322 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1323 } /* else everything is zero */ 1324 1325 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso)) 1326 return -EFAULT; 1327 1328 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso)); 1329 } 1330 1331 if (vlan_hlen) { 1332 int ret; 1333 struct { 1334 __be16 h_vlan_proto; 1335 __be16 h_vlan_TCI; 1336 } veth; 1337 1338 veth.h_vlan_proto = skb->vlan_proto; 1339 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 1340 1341 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1342 1343 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset); 1344 if (ret || !iov_iter_count(iter)) 1345 goto done; 1346 1347 ret = copy_to_iter(&veth, sizeof(veth), iter); 1348 if (ret != sizeof(veth) || !iov_iter_count(iter)) 1349 goto done; 1350 } 1351 1352 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset); 1353 1354 done: 1355 tun->dev->stats.tx_packets++; 1356 tun->dev->stats.tx_bytes += skb->len + vlan_hlen; 1357 1358 return total; 1359 } 1360 1361 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1362 struct iov_iter *to, 1363 int noblock) 1364 { 1365 struct sk_buff *skb; 1366 ssize_t ret; 1367 int peeked, err, off = 0; 1368 1369 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1370 1371 if (!iov_iter_count(to)) 1372 return 0; 1373 1374 if (tun->dev->reg_state != NETREG_REGISTERED) 1375 return -EIO; 1376 1377 /* Read frames from queue */ 1378 skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0, 1379 &peeked, &off, &err); 1380 if (!skb) 1381 return 0; 1382 1383 ret = tun_put_user(tun, tfile, skb, to); 1384 if (unlikely(ret < 0)) 1385 kfree_skb(skb); 1386 else 1387 consume_skb(skb); 1388 1389 return ret; 1390 } 1391 1392 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1393 { 1394 struct file *file = iocb->ki_filp; 1395 struct tun_file *tfile = file->private_data; 1396 struct tun_struct *tun = __tun_get(tfile); 1397 ssize_t len = iov_iter_count(to), ret; 1398 1399 if (!tun) 1400 return -EBADFD; 1401 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK); 1402 ret = min_t(ssize_t, ret, len); 1403 if (ret > 0) 1404 iocb->ki_pos = ret; 1405 tun_put(tun); 1406 return ret; 1407 } 1408 1409 static void tun_free_netdev(struct net_device *dev) 1410 { 1411 struct tun_struct *tun = netdev_priv(dev); 1412 1413 BUG_ON(!(list_empty(&tun->disabled))); 1414 tun_flow_uninit(tun); 1415 security_tun_dev_free_security(tun->security); 1416 free_netdev(dev); 1417 } 1418 1419 static void tun_setup(struct net_device *dev) 1420 { 1421 struct tun_struct *tun = netdev_priv(dev); 1422 1423 tun->owner = INVALID_UID; 1424 tun->group = INVALID_GID; 1425 1426 dev->ethtool_ops = &tun_ethtool_ops; 1427 dev->destructor = tun_free_netdev; 1428 } 1429 1430 /* Trivial set of netlink ops to allow deleting tun or tap 1431 * device with netlink. 1432 */ 1433 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1434 { 1435 return -EINVAL; 1436 } 1437 1438 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1439 .kind = DRV_NAME, 1440 .priv_size = sizeof(struct tun_struct), 1441 .setup = tun_setup, 1442 .validate = tun_validate, 1443 }; 1444 1445 static void tun_sock_write_space(struct sock *sk) 1446 { 1447 struct tun_file *tfile; 1448 wait_queue_head_t *wqueue; 1449 1450 if (!sock_writeable(sk)) 1451 return; 1452 1453 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1454 return; 1455 1456 wqueue = sk_sleep(sk); 1457 if (wqueue && waitqueue_active(wqueue)) 1458 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1459 POLLWRNORM | POLLWRBAND); 1460 1461 tfile = container_of(sk, struct tun_file, sk); 1462 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1463 } 1464 1465 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1466 struct msghdr *m, size_t total_len) 1467 { 1468 int ret; 1469 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1470 struct tun_struct *tun = __tun_get(tfile); 1471 1472 if (!tun) 1473 return -EBADFD; 1474 1475 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter, 1476 m->msg_flags & MSG_DONTWAIT); 1477 tun_put(tun); 1478 return ret; 1479 } 1480 1481 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1482 struct msghdr *m, size_t total_len, 1483 int flags) 1484 { 1485 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1486 struct tun_struct *tun = __tun_get(tfile); 1487 int ret; 1488 1489 if (!tun) 1490 return -EBADFD; 1491 1492 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1493 ret = -EINVAL; 1494 goto out; 1495 } 1496 if (flags & MSG_ERRQUEUE) { 1497 ret = sock_recv_errqueue(sock->sk, m, total_len, 1498 SOL_PACKET, TUN_TX_TIMESTAMP); 1499 goto out; 1500 } 1501 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT); 1502 if (ret > total_len) { 1503 m->msg_flags |= MSG_TRUNC; 1504 ret = flags & MSG_TRUNC ? ret : total_len; 1505 } 1506 out: 1507 tun_put(tun); 1508 return ret; 1509 } 1510 1511 static int tun_release(struct socket *sock) 1512 { 1513 if (sock->sk) 1514 sock_put(sock->sk); 1515 return 0; 1516 } 1517 1518 /* Ops structure to mimic raw sockets with tun */ 1519 static const struct proto_ops tun_socket_ops = { 1520 .sendmsg = tun_sendmsg, 1521 .recvmsg = tun_recvmsg, 1522 .release = tun_release, 1523 }; 1524 1525 static struct proto tun_proto = { 1526 .name = "tun", 1527 .owner = THIS_MODULE, 1528 .obj_size = sizeof(struct tun_file), 1529 }; 1530 1531 static int tun_flags(struct tun_struct *tun) 1532 { 1533 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP); 1534 } 1535 1536 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1537 char *buf) 1538 { 1539 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1540 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1541 } 1542 1543 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1544 char *buf) 1545 { 1546 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1547 return uid_valid(tun->owner)? 1548 sprintf(buf, "%u\n", 1549 from_kuid_munged(current_user_ns(), tun->owner)): 1550 sprintf(buf, "-1\n"); 1551 } 1552 1553 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1554 char *buf) 1555 { 1556 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1557 return gid_valid(tun->group) ? 1558 sprintf(buf, "%u\n", 1559 from_kgid_munged(current_user_ns(), tun->group)): 1560 sprintf(buf, "-1\n"); 1561 } 1562 1563 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1564 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1565 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1566 1567 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1568 { 1569 struct tun_struct *tun; 1570 struct tun_file *tfile = file->private_data; 1571 struct net_device *dev; 1572 int err; 1573 1574 if (tfile->detached) 1575 return -EINVAL; 1576 1577 dev = __dev_get_by_name(net, ifr->ifr_name); 1578 if (dev) { 1579 if (ifr->ifr_flags & IFF_TUN_EXCL) 1580 return -EBUSY; 1581 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1582 tun = netdev_priv(dev); 1583 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1584 tun = netdev_priv(dev); 1585 else 1586 return -EINVAL; 1587 1588 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1589 !!(tun->flags & IFF_MULTI_QUEUE)) 1590 return -EINVAL; 1591 1592 if (tun_not_capable(tun)) 1593 return -EPERM; 1594 err = security_tun_dev_open(tun->security); 1595 if (err < 0) 1596 return err; 1597 1598 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1599 if (err < 0) 1600 return err; 1601 1602 if (tun->flags & IFF_MULTI_QUEUE && 1603 (tun->numqueues + tun->numdisabled > 1)) { 1604 /* One or more queue has already been attached, no need 1605 * to initialize the device again. 1606 */ 1607 return 0; 1608 } 1609 } 1610 else { 1611 char *name; 1612 unsigned long flags = 0; 1613 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1614 MAX_TAP_QUEUES : 1; 1615 1616 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1617 return -EPERM; 1618 err = security_tun_dev_create(); 1619 if (err < 0) 1620 return err; 1621 1622 /* Set dev type */ 1623 if (ifr->ifr_flags & IFF_TUN) { 1624 /* TUN device */ 1625 flags |= IFF_TUN; 1626 name = "tun%d"; 1627 } else if (ifr->ifr_flags & IFF_TAP) { 1628 /* TAP device */ 1629 flags |= IFF_TAP; 1630 name = "tap%d"; 1631 } else 1632 return -EINVAL; 1633 1634 if (*ifr->ifr_name) 1635 name = ifr->ifr_name; 1636 1637 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1638 NET_NAME_UNKNOWN, tun_setup, queues, 1639 queues); 1640 1641 if (!dev) 1642 return -ENOMEM; 1643 1644 dev_net_set(dev, net); 1645 dev->rtnl_link_ops = &tun_link_ops; 1646 dev->ifindex = tfile->ifindex; 1647 1648 tun = netdev_priv(dev); 1649 tun->dev = dev; 1650 tun->flags = flags; 1651 tun->txflt.count = 0; 1652 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1653 1654 tun->filter_attached = false; 1655 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1656 1657 spin_lock_init(&tun->lock); 1658 1659 err = security_tun_dev_alloc_security(&tun->security); 1660 if (err < 0) 1661 goto err_free_dev; 1662 1663 tun_net_init(dev); 1664 tun_flow_init(tun); 1665 1666 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1667 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1668 NETIF_F_HW_VLAN_STAG_TX; 1669 dev->features = dev->hw_features; 1670 dev->vlan_features = dev->features & 1671 ~(NETIF_F_HW_VLAN_CTAG_TX | 1672 NETIF_F_HW_VLAN_STAG_TX); 1673 1674 INIT_LIST_HEAD(&tun->disabled); 1675 err = tun_attach(tun, file, false); 1676 if (err < 0) 1677 goto err_free_flow; 1678 1679 err = register_netdevice(tun->dev); 1680 if (err < 0) 1681 goto err_detach; 1682 1683 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1684 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1685 device_create_file(&tun->dev->dev, &dev_attr_group)) 1686 pr_err("Failed to create tun sysfs files\n"); 1687 } 1688 1689 netif_carrier_on(tun->dev); 1690 1691 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1692 1693 tun->flags = (tun->flags & ~TUN_FEATURES) | 1694 (ifr->ifr_flags & TUN_FEATURES); 1695 1696 /* Make sure persistent devices do not get stuck in 1697 * xoff state. 1698 */ 1699 if (netif_running(tun->dev)) 1700 netif_tx_wake_all_queues(tun->dev); 1701 1702 strcpy(ifr->ifr_name, tun->dev->name); 1703 return 0; 1704 1705 err_detach: 1706 tun_detach_all(dev); 1707 err_free_flow: 1708 tun_flow_uninit(tun); 1709 security_tun_dev_free_security(tun->security); 1710 err_free_dev: 1711 free_netdev(dev); 1712 return err; 1713 } 1714 1715 static void tun_get_iff(struct net *net, struct tun_struct *tun, 1716 struct ifreq *ifr) 1717 { 1718 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1719 1720 strcpy(ifr->ifr_name, tun->dev->name); 1721 1722 ifr->ifr_flags = tun_flags(tun); 1723 1724 } 1725 1726 /* This is like a cut-down ethtool ops, except done via tun fd so no 1727 * privs required. */ 1728 static int set_offload(struct tun_struct *tun, unsigned long arg) 1729 { 1730 netdev_features_t features = 0; 1731 1732 if (arg & TUN_F_CSUM) { 1733 features |= NETIF_F_HW_CSUM; 1734 arg &= ~TUN_F_CSUM; 1735 1736 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1737 if (arg & TUN_F_TSO_ECN) { 1738 features |= NETIF_F_TSO_ECN; 1739 arg &= ~TUN_F_TSO_ECN; 1740 } 1741 if (arg & TUN_F_TSO4) 1742 features |= NETIF_F_TSO; 1743 if (arg & TUN_F_TSO6) 1744 features |= NETIF_F_TSO6; 1745 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1746 } 1747 } 1748 1749 /* This gives the user a way to test for new features in future by 1750 * trying to set them. */ 1751 if (arg) 1752 return -EINVAL; 1753 1754 tun->set_features = features; 1755 netdev_update_features(tun->dev); 1756 1757 return 0; 1758 } 1759 1760 static void tun_detach_filter(struct tun_struct *tun, int n) 1761 { 1762 int i; 1763 struct tun_file *tfile; 1764 1765 for (i = 0; i < n; i++) { 1766 tfile = rtnl_dereference(tun->tfiles[i]); 1767 sk_detach_filter(tfile->socket.sk); 1768 } 1769 1770 tun->filter_attached = false; 1771 } 1772 1773 static int tun_attach_filter(struct tun_struct *tun) 1774 { 1775 int i, ret = 0; 1776 struct tun_file *tfile; 1777 1778 for (i = 0; i < tun->numqueues; i++) { 1779 tfile = rtnl_dereference(tun->tfiles[i]); 1780 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1781 if (ret) { 1782 tun_detach_filter(tun, i); 1783 return ret; 1784 } 1785 } 1786 1787 tun->filter_attached = true; 1788 return ret; 1789 } 1790 1791 static void tun_set_sndbuf(struct tun_struct *tun) 1792 { 1793 struct tun_file *tfile; 1794 int i; 1795 1796 for (i = 0; i < tun->numqueues; i++) { 1797 tfile = rtnl_dereference(tun->tfiles[i]); 1798 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1799 } 1800 } 1801 1802 static int tun_set_queue(struct file *file, struct ifreq *ifr) 1803 { 1804 struct tun_file *tfile = file->private_data; 1805 struct tun_struct *tun; 1806 int ret = 0; 1807 1808 rtnl_lock(); 1809 1810 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1811 tun = tfile->detached; 1812 if (!tun) { 1813 ret = -EINVAL; 1814 goto unlock; 1815 } 1816 ret = security_tun_dev_attach_queue(tun->security); 1817 if (ret < 0) 1818 goto unlock; 1819 ret = tun_attach(tun, file, false); 1820 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1821 tun = rtnl_dereference(tfile->tun); 1822 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached) 1823 ret = -EINVAL; 1824 else 1825 __tun_detach(tfile, false); 1826 } else 1827 ret = -EINVAL; 1828 1829 unlock: 1830 rtnl_unlock(); 1831 return ret; 1832 } 1833 1834 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1835 unsigned long arg, int ifreq_len) 1836 { 1837 struct tun_file *tfile = file->private_data; 1838 struct tun_struct *tun; 1839 void __user* argp = (void __user*)arg; 1840 struct ifreq ifr; 1841 kuid_t owner; 1842 kgid_t group; 1843 int sndbuf; 1844 int vnet_hdr_sz; 1845 unsigned int ifindex; 1846 int ret; 1847 1848 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1849 if (copy_from_user(&ifr, argp, ifreq_len)) 1850 return -EFAULT; 1851 } else { 1852 memset(&ifr, 0, sizeof(ifr)); 1853 } 1854 if (cmd == TUNGETFEATURES) { 1855 /* Currently this just means: "what IFF flags are valid?". 1856 * This is needed because we never checked for invalid flags on 1857 * TUNSETIFF. 1858 */ 1859 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES, 1860 (unsigned int __user*)argp); 1861 } else if (cmd == TUNSETQUEUE) 1862 return tun_set_queue(file, &ifr); 1863 1864 ret = 0; 1865 rtnl_lock(); 1866 1867 tun = __tun_get(tfile); 1868 if (cmd == TUNSETIFF && !tun) { 1869 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1870 1871 ret = tun_set_iff(tfile->net, file, &ifr); 1872 1873 if (ret) 1874 goto unlock; 1875 1876 if (copy_to_user(argp, &ifr, ifreq_len)) 1877 ret = -EFAULT; 1878 goto unlock; 1879 } 1880 if (cmd == TUNSETIFINDEX) { 1881 ret = -EPERM; 1882 if (tun) 1883 goto unlock; 1884 1885 ret = -EFAULT; 1886 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1887 goto unlock; 1888 1889 ret = 0; 1890 tfile->ifindex = ifindex; 1891 goto unlock; 1892 } 1893 1894 ret = -EBADFD; 1895 if (!tun) 1896 goto unlock; 1897 1898 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1899 1900 ret = 0; 1901 switch (cmd) { 1902 case TUNGETIFF: 1903 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1904 1905 if (tfile->detached) 1906 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1907 if (!tfile->socket.sk->sk_filter) 1908 ifr.ifr_flags |= IFF_NOFILTER; 1909 1910 if (copy_to_user(argp, &ifr, ifreq_len)) 1911 ret = -EFAULT; 1912 break; 1913 1914 case TUNSETNOCSUM: 1915 /* Disable/Enable checksum */ 1916 1917 /* [unimplemented] */ 1918 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1919 arg ? "disabled" : "enabled"); 1920 break; 1921 1922 case TUNSETPERSIST: 1923 /* Disable/Enable persist mode. Keep an extra reference to the 1924 * module to prevent the module being unprobed. 1925 */ 1926 if (arg && !(tun->flags & IFF_PERSIST)) { 1927 tun->flags |= IFF_PERSIST; 1928 __module_get(THIS_MODULE); 1929 } 1930 if (!arg && (tun->flags & IFF_PERSIST)) { 1931 tun->flags &= ~IFF_PERSIST; 1932 module_put(THIS_MODULE); 1933 } 1934 1935 tun_debug(KERN_INFO, tun, "persist %s\n", 1936 arg ? "enabled" : "disabled"); 1937 break; 1938 1939 case TUNSETOWNER: 1940 /* Set owner of the device */ 1941 owner = make_kuid(current_user_ns(), arg); 1942 if (!uid_valid(owner)) { 1943 ret = -EINVAL; 1944 break; 1945 } 1946 tun->owner = owner; 1947 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1948 from_kuid(&init_user_ns, tun->owner)); 1949 break; 1950 1951 case TUNSETGROUP: 1952 /* Set group of the device */ 1953 group = make_kgid(current_user_ns(), arg); 1954 if (!gid_valid(group)) { 1955 ret = -EINVAL; 1956 break; 1957 } 1958 tun->group = group; 1959 tun_debug(KERN_INFO, tun, "group set to %u\n", 1960 from_kgid(&init_user_ns, tun->group)); 1961 break; 1962 1963 case TUNSETLINK: 1964 /* Only allow setting the type when the interface is down */ 1965 if (tun->dev->flags & IFF_UP) { 1966 tun_debug(KERN_INFO, tun, 1967 "Linktype set failed because interface is up\n"); 1968 ret = -EBUSY; 1969 } else { 1970 tun->dev->type = (int) arg; 1971 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1972 tun->dev->type); 1973 ret = 0; 1974 } 1975 break; 1976 1977 #ifdef TUN_DEBUG 1978 case TUNSETDEBUG: 1979 tun->debug = arg; 1980 break; 1981 #endif 1982 case TUNSETOFFLOAD: 1983 ret = set_offload(tun, arg); 1984 break; 1985 1986 case TUNSETTXFILTER: 1987 /* Can be set only for TAPs */ 1988 ret = -EINVAL; 1989 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 1990 break; 1991 ret = update_filter(&tun->txflt, (void __user *)arg); 1992 break; 1993 1994 case SIOCGIFHWADDR: 1995 /* Get hw address */ 1996 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 1997 ifr.ifr_hwaddr.sa_family = tun->dev->type; 1998 if (copy_to_user(argp, &ifr, ifreq_len)) 1999 ret = -EFAULT; 2000 break; 2001 2002 case SIOCSIFHWADDR: 2003 /* Set hw address */ 2004 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 2005 ifr.ifr_hwaddr.sa_data); 2006 2007 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2008 break; 2009 2010 case TUNGETSNDBUF: 2011 sndbuf = tfile->socket.sk->sk_sndbuf; 2012 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2013 ret = -EFAULT; 2014 break; 2015 2016 case TUNSETSNDBUF: 2017 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2018 ret = -EFAULT; 2019 break; 2020 } 2021 2022 tun->sndbuf = sndbuf; 2023 tun_set_sndbuf(tun); 2024 break; 2025 2026 case TUNGETVNETHDRSZ: 2027 vnet_hdr_sz = tun->vnet_hdr_sz; 2028 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2029 ret = -EFAULT; 2030 break; 2031 2032 case TUNSETVNETHDRSZ: 2033 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2034 ret = -EFAULT; 2035 break; 2036 } 2037 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2038 ret = -EINVAL; 2039 break; 2040 } 2041 2042 tun->vnet_hdr_sz = vnet_hdr_sz; 2043 break; 2044 2045 case TUNATTACHFILTER: 2046 /* Can be set only for TAPs */ 2047 ret = -EINVAL; 2048 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2049 break; 2050 ret = -EFAULT; 2051 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2052 break; 2053 2054 ret = tun_attach_filter(tun); 2055 break; 2056 2057 case TUNDETACHFILTER: 2058 /* Can be set only for TAPs */ 2059 ret = -EINVAL; 2060 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2061 break; 2062 ret = 0; 2063 tun_detach_filter(tun, tun->numqueues); 2064 break; 2065 2066 case TUNGETFILTER: 2067 ret = -EINVAL; 2068 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2069 break; 2070 ret = -EFAULT; 2071 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2072 break; 2073 ret = 0; 2074 break; 2075 2076 default: 2077 ret = -EINVAL; 2078 break; 2079 } 2080 2081 unlock: 2082 rtnl_unlock(); 2083 if (tun) 2084 tun_put(tun); 2085 return ret; 2086 } 2087 2088 static long tun_chr_ioctl(struct file *file, 2089 unsigned int cmd, unsigned long arg) 2090 { 2091 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2092 } 2093 2094 #ifdef CONFIG_COMPAT 2095 static long tun_chr_compat_ioctl(struct file *file, 2096 unsigned int cmd, unsigned long arg) 2097 { 2098 switch (cmd) { 2099 case TUNSETIFF: 2100 case TUNGETIFF: 2101 case TUNSETTXFILTER: 2102 case TUNGETSNDBUF: 2103 case TUNSETSNDBUF: 2104 case SIOCGIFHWADDR: 2105 case SIOCSIFHWADDR: 2106 arg = (unsigned long)compat_ptr(arg); 2107 break; 2108 default: 2109 arg = (compat_ulong_t)arg; 2110 break; 2111 } 2112 2113 /* 2114 * compat_ifreq is shorter than ifreq, so we must not access beyond 2115 * the end of that structure. All fields that are used in this 2116 * driver are compatible though, we don't need to convert the 2117 * contents. 2118 */ 2119 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2120 } 2121 #endif /* CONFIG_COMPAT */ 2122 2123 static int tun_chr_fasync(int fd, struct file *file, int on) 2124 { 2125 struct tun_file *tfile = file->private_data; 2126 int ret; 2127 2128 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2129 goto out; 2130 2131 if (on) { 2132 __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2133 tfile->flags |= TUN_FASYNC; 2134 } else 2135 tfile->flags &= ~TUN_FASYNC; 2136 ret = 0; 2137 out: 2138 return ret; 2139 } 2140 2141 static int tun_chr_open(struct inode *inode, struct file * file) 2142 { 2143 struct tun_file *tfile; 2144 2145 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2146 2147 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2148 &tun_proto); 2149 if (!tfile) 2150 return -ENOMEM; 2151 RCU_INIT_POINTER(tfile->tun, NULL); 2152 tfile->net = get_net(current->nsproxy->net_ns); 2153 tfile->flags = 0; 2154 tfile->ifindex = 0; 2155 2156 init_waitqueue_head(&tfile->wq.wait); 2157 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq); 2158 2159 tfile->socket.file = file; 2160 tfile->socket.ops = &tun_socket_ops; 2161 2162 sock_init_data(&tfile->socket, &tfile->sk); 2163 sk_change_net(&tfile->sk, tfile->net); 2164 2165 tfile->sk.sk_write_space = tun_sock_write_space; 2166 tfile->sk.sk_sndbuf = INT_MAX; 2167 2168 file->private_data = tfile; 2169 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2170 INIT_LIST_HEAD(&tfile->next); 2171 2172 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2173 2174 return 0; 2175 } 2176 2177 static int tun_chr_close(struct inode *inode, struct file *file) 2178 { 2179 struct tun_file *tfile = file->private_data; 2180 struct net *net = tfile->net; 2181 2182 tun_detach(tfile, true); 2183 put_net(net); 2184 2185 return 0; 2186 } 2187 2188 #ifdef CONFIG_PROC_FS 2189 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f) 2190 { 2191 struct tun_struct *tun; 2192 struct ifreq ifr; 2193 2194 memset(&ifr, 0, sizeof(ifr)); 2195 2196 rtnl_lock(); 2197 tun = tun_get(f); 2198 if (tun) 2199 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 2200 rtnl_unlock(); 2201 2202 if (tun) 2203 tun_put(tun); 2204 2205 seq_printf(m, "iff:\t%s\n", ifr.ifr_name); 2206 } 2207 #endif 2208 2209 static const struct file_operations tun_fops = { 2210 .owner = THIS_MODULE, 2211 .llseek = no_llseek, 2212 .read = new_sync_read, 2213 .write = new_sync_write, 2214 .read_iter = tun_chr_read_iter, 2215 .write_iter = tun_chr_write_iter, 2216 .poll = tun_chr_poll, 2217 .unlocked_ioctl = tun_chr_ioctl, 2218 #ifdef CONFIG_COMPAT 2219 .compat_ioctl = tun_chr_compat_ioctl, 2220 #endif 2221 .open = tun_chr_open, 2222 .release = tun_chr_close, 2223 .fasync = tun_chr_fasync, 2224 #ifdef CONFIG_PROC_FS 2225 .show_fdinfo = tun_chr_show_fdinfo, 2226 #endif 2227 }; 2228 2229 static struct miscdevice tun_miscdev = { 2230 .minor = TUN_MINOR, 2231 .name = "tun", 2232 .nodename = "net/tun", 2233 .fops = &tun_fops, 2234 }; 2235 2236 /* ethtool interface */ 2237 2238 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2239 { 2240 cmd->supported = 0; 2241 cmd->advertising = 0; 2242 ethtool_cmd_speed_set(cmd, SPEED_10); 2243 cmd->duplex = DUPLEX_FULL; 2244 cmd->port = PORT_TP; 2245 cmd->phy_address = 0; 2246 cmd->transceiver = XCVR_INTERNAL; 2247 cmd->autoneg = AUTONEG_DISABLE; 2248 cmd->maxtxpkt = 0; 2249 cmd->maxrxpkt = 0; 2250 return 0; 2251 } 2252 2253 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2254 { 2255 struct tun_struct *tun = netdev_priv(dev); 2256 2257 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2258 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2259 2260 switch (tun->flags & TUN_TYPE_MASK) { 2261 case IFF_TUN: 2262 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2263 break; 2264 case IFF_TAP: 2265 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2266 break; 2267 } 2268 } 2269 2270 static u32 tun_get_msglevel(struct net_device *dev) 2271 { 2272 #ifdef TUN_DEBUG 2273 struct tun_struct *tun = netdev_priv(dev); 2274 return tun->debug; 2275 #else 2276 return -EOPNOTSUPP; 2277 #endif 2278 } 2279 2280 static void tun_set_msglevel(struct net_device *dev, u32 value) 2281 { 2282 #ifdef TUN_DEBUG 2283 struct tun_struct *tun = netdev_priv(dev); 2284 tun->debug = value; 2285 #endif 2286 } 2287 2288 static const struct ethtool_ops tun_ethtool_ops = { 2289 .get_settings = tun_get_settings, 2290 .get_drvinfo = tun_get_drvinfo, 2291 .get_msglevel = tun_get_msglevel, 2292 .set_msglevel = tun_set_msglevel, 2293 .get_link = ethtool_op_get_link, 2294 .get_ts_info = ethtool_op_get_ts_info, 2295 }; 2296 2297 2298 static int __init tun_init(void) 2299 { 2300 int ret = 0; 2301 2302 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2303 pr_info("%s\n", DRV_COPYRIGHT); 2304 2305 ret = rtnl_link_register(&tun_link_ops); 2306 if (ret) { 2307 pr_err("Can't register link_ops\n"); 2308 goto err_linkops; 2309 } 2310 2311 ret = misc_register(&tun_miscdev); 2312 if (ret) { 2313 pr_err("Can't register misc device %d\n", TUN_MINOR); 2314 goto err_misc; 2315 } 2316 return 0; 2317 err_misc: 2318 rtnl_link_unregister(&tun_link_ops); 2319 err_linkops: 2320 return ret; 2321 } 2322 2323 static void tun_cleanup(void) 2324 { 2325 misc_deregister(&tun_miscdev); 2326 rtnl_link_unregister(&tun_link_ops); 2327 } 2328 2329 /* Get an underlying socket object from tun file. Returns error unless file is 2330 * attached to a device. The returned object works like a packet socket, it 2331 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2332 * holding a reference to the file for as long as the socket is in use. */ 2333 struct socket *tun_get_socket(struct file *file) 2334 { 2335 struct tun_file *tfile; 2336 if (file->f_op != &tun_fops) 2337 return ERR_PTR(-EINVAL); 2338 tfile = file->private_data; 2339 if (!tfile) 2340 return ERR_PTR(-EBADFD); 2341 return &tfile->socket; 2342 } 2343 EXPORT_SYMBOL_GPL(tun_get_socket); 2344 2345 module_init(tun_init); 2346 module_exit(tun_cleanup); 2347 MODULE_DESCRIPTION(DRV_DESCRIPTION); 2348 MODULE_AUTHOR(DRV_COPYRIGHT); 2349 MODULE_LICENSE("GPL"); 2350 MODULE_ALIAS_MISCDEV(TUN_MINOR); 2351 MODULE_ALIAS("devname:net/tun"); 2352