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/net_namespace.h> 69#include <net/netns/generic.h> 70#include <net/rtnetlink.h> 71#include <net/sock.h> 72#include <linux/seq_file.h> 73#include <linux/uio.h> 74 75#include <asm/uaccess.h> 76 77/* Uncomment to enable debugging */ 78/* #define TUN_DEBUG 1 */ 79 80#ifdef TUN_DEBUG 81static int debug; 82 83#define tun_debug(level, tun, fmt, args...) \ 84do { \ 85 if (tun->debug) \ 86 netdev_printk(level, tun->dev, fmt, ##args); \ 87} while (0) 88#define DBG1(level, fmt, args...) \ 89do { \ 90 if (debug == 2) \ 91 printk(level fmt, ##args); \ 92} while (0) 93#else 94#define tun_debug(level, tun, fmt, args...) \ 95do { \ 96 if (0) \ 97 netdev_printk(level, tun->dev, fmt, ##args); \ 98} while (0) 99#define DBG1(level, fmt, args...) \ 100do { \ 101 if (0) \ 102 printk(level fmt, ##args); \ 103} while (0) 104#endif 105 106/* TUN device flags */ 107 108/* IFF_ATTACH_QUEUE is never stored in device flags, 109 * overload it to mean fasync when stored there. 110 */ 111#define TUN_FASYNC IFF_ATTACH_QUEUE 112/* High bits in flags field are unused. */ 113#define TUN_VNET_LE 0x80000000 114 115#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \ 116 IFF_MULTI_QUEUE) 117#define GOODCOPY_LEN 128 118 119#define FLT_EXACT_COUNT 8 120struct tap_filter { 121 unsigned int count; /* Number of addrs. Zero means disabled */ 122 u32 mask[2]; /* Mask of the hashed addrs */ 123 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 124}; 125 126/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal 127 * to max number of VCPUs in guest. */ 128#define MAX_TAP_QUEUES 256 129#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 */ 144struct 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 161struct 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 */ 178struct 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|NETIF_F_UFO) 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 209static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) 210{ 211 return __virtio16_to_cpu(tun->flags & TUN_VNET_LE, val); 212} 213 214static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val) 215{ 216 return __cpu_to_virtio16(tun->flags & TUN_VNET_LE, val); 217} 218 219static inline u32 tun_hashfn(u32 rxhash) 220{ 221 return rxhash & 0x3ff; 222} 223 224static 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 235static 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 255static 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 hlist_del_rcu(&e->hash_link); 260 kfree_rcu(e, rcu); 261 --tun->flow_count; 262} 263 264static void tun_flow_flush(struct tun_struct *tun) 265{ 266 int i; 267 268 spin_lock_bh(&tun->lock); 269 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 270 struct tun_flow_entry *e; 271 struct hlist_node *n; 272 273 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) 274 tun_flow_delete(tun, e); 275 } 276 spin_unlock_bh(&tun->lock); 277} 278 279static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) 280{ 281 int i; 282 283 spin_lock_bh(&tun->lock); 284 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 285 struct tun_flow_entry *e; 286 struct hlist_node *n; 287 288 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 289 if (e->queue_index == queue_index) 290 tun_flow_delete(tun, e); 291 } 292 } 293 spin_unlock_bh(&tun->lock); 294} 295 296static void tun_flow_cleanup(unsigned long data) 297{ 298 struct tun_struct *tun = (struct tun_struct *)data; 299 unsigned long delay = tun->ageing_time; 300 unsigned long next_timer = jiffies + delay; 301 unsigned long count = 0; 302 int i; 303 304 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n"); 305 306 spin_lock_bh(&tun->lock); 307 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { 308 struct tun_flow_entry *e; 309 struct hlist_node *n; 310 311 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { 312 unsigned long this_timer; 313 count++; 314 this_timer = e->updated + delay; 315 if (time_before_eq(this_timer, jiffies)) 316 tun_flow_delete(tun, e); 317 else if (time_before(this_timer, next_timer)) 318 next_timer = this_timer; 319 } 320 } 321 322 if (count) 323 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer)); 324 spin_unlock_bh(&tun->lock); 325} 326 327static void tun_flow_update(struct tun_struct *tun, u32 rxhash, 328 struct tun_file *tfile) 329{ 330 struct hlist_head *head; 331 struct tun_flow_entry *e; 332 unsigned long delay = tun->ageing_time; 333 u16 queue_index = tfile->queue_index; 334 335 if (!rxhash) 336 return; 337 else 338 head = &tun->flows[tun_hashfn(rxhash)]; 339 340 rcu_read_lock(); 341 342 /* We may get a very small possibility of OOO during switching, not 343 * worth to optimize.*/ 344 if (tun->numqueues == 1 || tfile->detached) 345 goto unlock; 346 347 e = tun_flow_find(head, rxhash); 348 if (likely(e)) { 349 /* TODO: keep queueing to old queue until it's empty? */ 350 e->queue_index = queue_index; 351 e->updated = jiffies; 352 sock_rps_record_flow_hash(e->rps_rxhash); 353 } else { 354 spin_lock_bh(&tun->lock); 355 if (!tun_flow_find(head, rxhash) && 356 tun->flow_count < MAX_TAP_FLOWS) 357 tun_flow_create(tun, head, rxhash, queue_index); 358 359 if (!timer_pending(&tun->flow_gc_timer)) 360 mod_timer(&tun->flow_gc_timer, 361 round_jiffies_up(jiffies + delay)); 362 spin_unlock_bh(&tun->lock); 363 } 364 365unlock: 366 rcu_read_unlock(); 367} 368 369/** 370 * Save the hash received in the stack receive path and update the 371 * flow_hash table accordingly. 372 */ 373static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) 374{ 375 if (unlikely(e->rps_rxhash != hash)) 376 e->rps_rxhash = hash; 377} 378 379/* We try to identify a flow through its rxhash first. The reason that 380 * we do not check rxq no. is because some cards(e.g 82599), chooses 381 * the rxq based on the txq where the last packet of the flow comes. As 382 * the userspace application move between processors, we may get a 383 * different rxq no. here. If we could not get rxhash, then we would 384 * hope the rxq no. may help here. 385 */ 386static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, 387 void *accel_priv, select_queue_fallback_t fallback) 388{ 389 struct tun_struct *tun = netdev_priv(dev); 390 struct tun_flow_entry *e; 391 u32 txq = 0; 392 u32 numqueues = 0; 393 394 rcu_read_lock(); 395 numqueues = ACCESS_ONCE(tun->numqueues); 396 397 txq = skb_get_hash(skb); 398 if (txq) { 399 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); 400 if (e) { 401 tun_flow_save_rps_rxhash(e, txq); 402 txq = e->queue_index; 403 } else 404 /* use multiply and shift instead of expensive divide */ 405 txq = ((u64)txq * numqueues) >> 32; 406 } else if (likely(skb_rx_queue_recorded(skb))) { 407 txq = skb_get_rx_queue(skb); 408 while (unlikely(txq >= numqueues)) 409 txq -= numqueues; 410 } 411 412 rcu_read_unlock(); 413 return txq; 414} 415 416static inline bool tun_not_capable(struct tun_struct *tun) 417{ 418 const struct cred *cred = current_cred(); 419 struct net *net = dev_net(tun->dev); 420 421 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 422 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 423 !ns_capable(net->user_ns, CAP_NET_ADMIN); 424} 425 426static void tun_set_real_num_queues(struct tun_struct *tun) 427{ 428 netif_set_real_num_tx_queues(tun->dev, tun->numqueues); 429 netif_set_real_num_rx_queues(tun->dev, tun->numqueues); 430} 431 432static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) 433{ 434 tfile->detached = tun; 435 list_add_tail(&tfile->next, &tun->disabled); 436 ++tun->numdisabled; 437} 438 439static struct tun_struct *tun_enable_queue(struct tun_file *tfile) 440{ 441 struct tun_struct *tun = tfile->detached; 442 443 tfile->detached = NULL; 444 list_del_init(&tfile->next); 445 --tun->numdisabled; 446 return tun; 447} 448 449static void tun_queue_purge(struct tun_file *tfile) 450{ 451 skb_queue_purge(&tfile->sk.sk_receive_queue); 452 skb_queue_purge(&tfile->sk.sk_error_queue); 453} 454 455static void __tun_detach(struct tun_file *tfile, bool clean) 456{ 457 struct tun_file *ntfile; 458 struct tun_struct *tun; 459 460 tun = rtnl_dereference(tfile->tun); 461 462 if (tun && !tfile->detached) { 463 u16 index = tfile->queue_index; 464 BUG_ON(index >= tun->numqueues); 465 466 rcu_assign_pointer(tun->tfiles[index], 467 tun->tfiles[tun->numqueues - 1]); 468 ntfile = rtnl_dereference(tun->tfiles[index]); 469 ntfile->queue_index = index; 470 471 --tun->numqueues; 472 if (clean) { 473 RCU_INIT_POINTER(tfile->tun, NULL); 474 sock_put(&tfile->sk); 475 } else 476 tun_disable_queue(tun, tfile); 477 478 synchronize_net(); 479 tun_flow_delete_by_queue(tun, tun->numqueues + 1); 480 /* Drop read queue */ 481 tun_queue_purge(tfile); 482 tun_set_real_num_queues(tun); 483 } else if (tfile->detached && clean) { 484 tun = tun_enable_queue(tfile); 485 sock_put(&tfile->sk); 486 } 487 488 if (clean) { 489 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) { 490 netif_carrier_off(tun->dev); 491 492 if (!(tun->flags & IFF_PERSIST) && 493 tun->dev->reg_state == NETREG_REGISTERED) 494 unregister_netdevice(tun->dev); 495 } 496 497 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, 498 &tfile->socket.flags)); 499 sk_release_kernel(&tfile->sk); 500 } 501} 502 503static void tun_detach(struct tun_file *tfile, bool clean) 504{ 505 rtnl_lock(); 506 __tun_detach(tfile, clean); 507 rtnl_unlock(); 508} 509 510static void tun_detach_all(struct net_device *dev) 511{ 512 struct tun_struct *tun = netdev_priv(dev); 513 struct tun_file *tfile, *tmp; 514 int i, n = tun->numqueues; 515 516 for (i = 0; i < n; i++) { 517 tfile = rtnl_dereference(tun->tfiles[i]); 518 BUG_ON(!tfile); 519 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 520 RCU_INIT_POINTER(tfile->tun, NULL); 521 --tun->numqueues; 522 } 523 list_for_each_entry(tfile, &tun->disabled, next) { 524 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 525 RCU_INIT_POINTER(tfile->tun, NULL); 526 } 527 BUG_ON(tun->numqueues != 0); 528 529 synchronize_net(); 530 for (i = 0; i < n; i++) { 531 tfile = rtnl_dereference(tun->tfiles[i]); 532 /* Drop read queue */ 533 tun_queue_purge(tfile); 534 sock_put(&tfile->sk); 535 } 536 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { 537 tun_enable_queue(tfile); 538 tun_queue_purge(tfile); 539 sock_put(&tfile->sk); 540 } 541 BUG_ON(tun->numdisabled != 0); 542 543 if (tun->flags & IFF_PERSIST) 544 module_put(THIS_MODULE); 545} 546 547static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) 548{ 549 struct tun_file *tfile = file->private_data; 550 int err; 551 552 err = security_tun_dev_attach(tfile->socket.sk, tun->security); 553 if (err < 0) 554 goto out; 555 556 err = -EINVAL; 557 if (rtnl_dereference(tfile->tun) && !tfile->detached) 558 goto out; 559 560 err = -EBUSY; 561 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1) 562 goto out; 563 564 err = -E2BIG; 565 if (!tfile->detached && 566 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES) 567 goto out; 568 569 err = 0; 570 571 /* Re-attach the filter to persist device */ 572 if (!skip_filter && (tun->filter_attached == true)) { 573 err = sk_attach_filter(&tun->fprog, tfile->socket.sk); 574 if (!err) 575 goto out; 576 } 577 tfile->queue_index = tun->numqueues; 578 rcu_assign_pointer(tfile->tun, tun); 579 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); 580 tun->numqueues++; 581 582 if (tfile->detached) 583 tun_enable_queue(tfile); 584 else 585 sock_hold(&tfile->sk); 586 587 tun_set_real_num_queues(tun); 588 589 /* device is allowed to go away first, so no need to hold extra 590 * refcnt. 591 */ 592 593out: 594 return err; 595} 596 597static struct tun_struct *__tun_get(struct tun_file *tfile) 598{ 599 struct tun_struct *tun; 600 601 rcu_read_lock(); 602 tun = rcu_dereference(tfile->tun); 603 if (tun) 604 dev_hold(tun->dev); 605 rcu_read_unlock(); 606 607 return tun; 608} 609 610static struct tun_struct *tun_get(struct file *file) 611{ 612 return __tun_get(file->private_data); 613} 614 615static void tun_put(struct tun_struct *tun) 616{ 617 dev_put(tun->dev); 618} 619 620/* TAP filtering */ 621static void addr_hash_set(u32 *mask, const u8 *addr) 622{ 623 int n = ether_crc(ETH_ALEN, addr) >> 26; 624 mask[n >> 5] |= (1 << (n & 31)); 625} 626 627static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 628{ 629 int n = ether_crc(ETH_ALEN, addr) >> 26; 630 return mask[n >> 5] & (1 << (n & 31)); 631} 632 633static int update_filter(struct tap_filter *filter, void __user *arg) 634{ 635 struct { u8 u[ETH_ALEN]; } *addr; 636 struct tun_filter uf; 637 int err, alen, n, nexact; 638 639 if (copy_from_user(&uf, arg, sizeof(uf))) 640 return -EFAULT; 641 642 if (!uf.count) { 643 /* Disabled */ 644 filter->count = 0; 645 return 0; 646 } 647 648 alen = ETH_ALEN * uf.count; 649 addr = kmalloc(alen, GFP_KERNEL); 650 if (!addr) 651 return -ENOMEM; 652 653 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 654 err = -EFAULT; 655 goto done; 656 } 657 658 /* The filter is updated without holding any locks. Which is 659 * perfectly safe. We disable it first and in the worst 660 * case we'll accept a few undesired packets. */ 661 filter->count = 0; 662 wmb(); 663 664 /* Use first set of addresses as an exact filter */ 665 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 666 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 667 668 nexact = n; 669 670 /* Remaining multicast addresses are hashed, 671 * unicast will leave the filter disabled. */ 672 memset(filter->mask, 0, sizeof(filter->mask)); 673 for (; n < uf.count; n++) { 674 if (!is_multicast_ether_addr(addr[n].u)) { 675 err = 0; /* no filter */ 676 goto done; 677 } 678 addr_hash_set(filter->mask, addr[n].u); 679 } 680 681 /* For ALLMULTI just set the mask to all ones. 682 * This overrides the mask populated above. */ 683 if ((uf.flags & TUN_FLT_ALLMULTI)) 684 memset(filter->mask, ~0, sizeof(filter->mask)); 685 686 /* Now enable the filter */ 687 wmb(); 688 filter->count = nexact; 689 690 /* Return the number of exact filters */ 691 err = nexact; 692 693done: 694 kfree(addr); 695 return err; 696} 697 698/* Returns: 0 - drop, !=0 - accept */ 699static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 700{ 701 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 702 * at this point. */ 703 struct ethhdr *eh = (struct ethhdr *) skb->data; 704 int i; 705 706 /* Exact match */ 707 for (i = 0; i < filter->count; i++) 708 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 709 return 1; 710 711 /* Inexact match (multicast only) */ 712 if (is_multicast_ether_addr(eh->h_dest)) 713 return addr_hash_test(filter->mask, eh->h_dest); 714 715 return 0; 716} 717 718/* 719 * Checks whether the packet is accepted or not. 720 * Returns: 0 - drop, !=0 - accept 721 */ 722static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 723{ 724 if (!filter->count) 725 return 1; 726 727 return run_filter(filter, skb); 728} 729 730/* Network device part of the driver */ 731 732static const struct ethtool_ops tun_ethtool_ops; 733 734/* Net device detach from fd. */ 735static void tun_net_uninit(struct net_device *dev) 736{ 737 tun_detach_all(dev); 738} 739 740/* Net device open. */ 741static int tun_net_open(struct net_device *dev) 742{ 743 netif_tx_start_all_queues(dev); 744 return 0; 745} 746 747/* Net device close. */ 748static int tun_net_close(struct net_device *dev) 749{ 750 netif_tx_stop_all_queues(dev); 751 return 0; 752} 753 754/* Net device start xmit */ 755static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 756{ 757 struct tun_struct *tun = netdev_priv(dev); 758 int txq = skb->queue_mapping; 759 struct tun_file *tfile; 760 u32 numqueues = 0; 761 762 rcu_read_lock(); 763 tfile = rcu_dereference(tun->tfiles[txq]); 764 numqueues = ACCESS_ONCE(tun->numqueues); 765 766 /* Drop packet if interface is not attached */ 767 if (txq >= numqueues) 768 goto drop; 769 770 if (numqueues == 1) { 771 /* Select queue was not called for the skbuff, so we extract the 772 * RPS hash and save it into the flow_table here. 773 */ 774 __u32 rxhash; 775 776 rxhash = skb_get_hash(skb); 777 if (rxhash) { 778 struct tun_flow_entry *e; 779 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], 780 rxhash); 781 if (e) 782 tun_flow_save_rps_rxhash(e, rxhash); 783 } 784 } 785 786 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 787 788 BUG_ON(!tfile); 789 790 /* Drop if the filter does not like it. 791 * This is a noop if the filter is disabled. 792 * Filter can be enabled only for the TAP devices. */ 793 if (!check_filter(&tun->txflt, skb)) 794 goto drop; 795 796 if (tfile->socket.sk->sk_filter && 797 sk_filter(tfile->socket.sk, skb)) 798 goto drop; 799 800 /* Limit the number of packets queued by dividing txq length with the 801 * number of queues. 802 */ 803 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues 804 >= dev->tx_queue_len) 805 goto drop; 806 807 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 808 goto drop; 809 810 if (skb->sk) { 811 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags); 812 sw_tx_timestamp(skb); 813 } 814 815 /* Orphan the skb - required as we might hang on to it 816 * for indefinite time. 817 */ 818 skb_orphan(skb); 819 820 nf_reset(skb); 821 822 /* Enqueue packet */ 823 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); 824 825 /* Notify and wake up reader process */ 826 if (tfile->flags & TUN_FASYNC) 827 kill_fasync(&tfile->fasync, SIGIO, POLL_IN); 828 tfile->socket.sk->sk_data_ready(tfile->socket.sk); 829 830 rcu_read_unlock(); 831 return NETDEV_TX_OK; 832 833drop: 834 dev->stats.tx_dropped++; 835 skb_tx_error(skb); 836 kfree_skb(skb); 837 rcu_read_unlock(); 838 return NET_XMIT_DROP; 839} 840 841static void tun_net_mclist(struct net_device *dev) 842{ 843 /* 844 * This callback is supposed to deal with mc filter in 845 * _rx_ path and has nothing to do with the _tx_ path. 846 * In rx path we always accept everything userspace gives us. 847 */ 848} 849 850#define MIN_MTU 68 851#define MAX_MTU 65535 852 853static int 854tun_net_change_mtu(struct net_device *dev, int new_mtu) 855{ 856 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 857 return -EINVAL; 858 dev->mtu = new_mtu; 859 return 0; 860} 861 862static netdev_features_t tun_net_fix_features(struct net_device *dev, 863 netdev_features_t features) 864{ 865 struct tun_struct *tun = netdev_priv(dev); 866 867 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 868} 869#ifdef CONFIG_NET_POLL_CONTROLLER 870static void tun_poll_controller(struct net_device *dev) 871{ 872 /* 873 * Tun only receives frames when: 874 * 1) the char device endpoint gets data from user space 875 * 2) the tun socket gets a sendmsg call from user space 876 * Since both of those are synchronous operations, we are guaranteed 877 * never to have pending data when we poll for it 878 * so there is nothing to do here but return. 879 * We need this though so netpoll recognizes us as an interface that 880 * supports polling, which enables bridge devices in virt setups to 881 * still use netconsole 882 */ 883 return; 884} 885#endif 886static const struct net_device_ops tun_netdev_ops = { 887 .ndo_uninit = tun_net_uninit, 888 .ndo_open = tun_net_open, 889 .ndo_stop = tun_net_close, 890 .ndo_start_xmit = tun_net_xmit, 891 .ndo_change_mtu = tun_net_change_mtu, 892 .ndo_fix_features = tun_net_fix_features, 893 .ndo_select_queue = tun_select_queue, 894#ifdef CONFIG_NET_POLL_CONTROLLER 895 .ndo_poll_controller = tun_poll_controller, 896#endif 897}; 898 899static const struct net_device_ops tap_netdev_ops = { 900 .ndo_uninit = tun_net_uninit, 901 .ndo_open = tun_net_open, 902 .ndo_stop = tun_net_close, 903 .ndo_start_xmit = tun_net_xmit, 904 .ndo_change_mtu = tun_net_change_mtu, 905 .ndo_fix_features = tun_net_fix_features, 906 .ndo_set_rx_mode = tun_net_mclist, 907 .ndo_set_mac_address = eth_mac_addr, 908 .ndo_validate_addr = eth_validate_addr, 909 .ndo_select_queue = tun_select_queue, 910#ifdef CONFIG_NET_POLL_CONTROLLER 911 .ndo_poll_controller = tun_poll_controller, 912#endif 913}; 914 915static void tun_flow_init(struct tun_struct *tun) 916{ 917 int i; 918 919 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) 920 INIT_HLIST_HEAD(&tun->flows[i]); 921 922 tun->ageing_time = TUN_FLOW_EXPIRE; 923 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 924 mod_timer(&tun->flow_gc_timer, 925 round_jiffies_up(jiffies + tun->ageing_time)); 926} 927 928static void tun_flow_uninit(struct tun_struct *tun) 929{ 930 del_timer_sync(&tun->flow_gc_timer); 931 tun_flow_flush(tun); 932} 933 934/* Initialize net device. */ 935static void tun_net_init(struct net_device *dev) 936{ 937 struct tun_struct *tun = netdev_priv(dev); 938 939 switch (tun->flags & TUN_TYPE_MASK) { 940 case IFF_TUN: 941 dev->netdev_ops = &tun_netdev_ops; 942 943 /* Point-to-Point TUN Device */ 944 dev->hard_header_len = 0; 945 dev->addr_len = 0; 946 dev->mtu = 1500; 947 948 /* Zero header length */ 949 dev->type = ARPHRD_NONE; 950 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 951 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 952 break; 953 954 case IFF_TAP: 955 dev->netdev_ops = &tap_netdev_ops; 956 /* Ethernet TAP Device */ 957 ether_setup(dev); 958 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 959 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 960 961 eth_hw_addr_random(dev); 962 963 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 964 break; 965 } 966} 967 968/* Character device part */ 969 970/* Poll */ 971static unsigned int tun_chr_poll(struct file *file, poll_table *wait) 972{ 973 struct tun_file *tfile = file->private_data; 974 struct tun_struct *tun = __tun_get(tfile); 975 struct sock *sk; 976 unsigned int mask = 0; 977 978 if (!tun) 979 return POLLERR; 980 981 sk = tfile->socket.sk; 982 983 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 984 985 poll_wait(file, sk_sleep(sk), wait); 986 987 if (!skb_queue_empty(&sk->sk_receive_queue)) 988 mask |= POLLIN | POLLRDNORM; 989 990 if (sock_writeable(sk) || 991 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 992 sock_writeable(sk))) 993 mask |= POLLOUT | POLLWRNORM; 994 995 if (tun->dev->reg_state != NETREG_REGISTERED) 996 mask = POLLERR; 997 998 tun_put(tun); 999 return mask; 1000} 1001 1002/* prepad is the amount to reserve at front. len is length after that. 1003 * linear is a hint as to how much to copy (usually headers). */ 1004static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, 1005 size_t prepad, size_t len, 1006 size_t linear, int noblock) 1007{ 1008 struct sock *sk = tfile->socket.sk; 1009 struct sk_buff *skb; 1010 int err; 1011 1012 /* Under a page? Don't bother with paged skb. */ 1013 if (prepad + len < PAGE_SIZE || !linear) 1014 linear = len; 1015 1016 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 1017 &err, 0); 1018 if (!skb) 1019 return ERR_PTR(err); 1020 1021 skb_reserve(skb, prepad); 1022 skb_put(skb, linear); 1023 skb->data_len = len - linear; 1024 skb->len += len - linear; 1025 1026 return skb; 1027} 1028 1029/* Get packet from user space buffer */ 1030static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 1031 void *msg_control, struct iov_iter *from, 1032 int noblock) 1033{ 1034 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 1035 struct sk_buff *skb; 1036 size_t total_len = iov_iter_count(from); 1037 size_t len = total_len, align = NET_SKB_PAD, linear; 1038 struct virtio_net_hdr gso = { 0 }; 1039 int good_linear; 1040 int copylen; 1041 bool zerocopy = false; 1042 int err; 1043 u32 rxhash; 1044 ssize_t n; 1045 1046 if (!(tun->flags & IFF_NO_PI)) { 1047 if (len < sizeof(pi)) 1048 return -EINVAL; 1049 len -= sizeof(pi); 1050 1051 n = copy_from_iter(&pi, sizeof(pi), from); 1052 if (n != sizeof(pi)) 1053 return -EFAULT; 1054 } 1055 1056 if (tun->flags & IFF_VNET_HDR) { 1057 if (len < tun->vnet_hdr_sz) 1058 return -EINVAL; 1059 len -= tun->vnet_hdr_sz; 1060 1061 n = copy_from_iter(&gso, sizeof(gso), from); 1062 if (n != sizeof(gso)) 1063 return -EFAULT; 1064 1065 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 1066 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len)) 1067 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2); 1068 1069 if (tun16_to_cpu(tun, gso.hdr_len) > len) 1070 return -EINVAL; 1071 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso)); 1072 } 1073 1074 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) { 1075 align += NET_IP_ALIGN; 1076 if (unlikely(len < ETH_HLEN || 1077 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN))) 1078 return -EINVAL; 1079 } 1080 1081 good_linear = SKB_MAX_HEAD(align); 1082 1083 if (msg_control) { 1084 struct iov_iter i = *from; 1085 1086 /* There are 256 bytes to be copied in skb, so there is 1087 * enough room for skb expand head in case it is used. 1088 * The rest of the buffer is mapped from userspace. 1089 */ 1090 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN; 1091 if (copylen > good_linear) 1092 copylen = good_linear; 1093 linear = copylen; 1094 iov_iter_advance(&i, copylen); 1095 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS) 1096 zerocopy = true; 1097 } 1098 1099 if (!zerocopy) { 1100 copylen = len; 1101 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear) 1102 linear = good_linear; 1103 else 1104 linear = tun16_to_cpu(tun, gso.hdr_len); 1105 } 1106 1107 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); 1108 if (IS_ERR(skb)) { 1109 if (PTR_ERR(skb) != -EAGAIN) 1110 tun->dev->stats.rx_dropped++; 1111 return PTR_ERR(skb); 1112 } 1113 1114 if (zerocopy) 1115 err = zerocopy_sg_from_iter(skb, from); 1116 else { 1117 err = skb_copy_datagram_from_iter(skb, 0, from, len); 1118 if (!err && msg_control) { 1119 struct ubuf_info *uarg = msg_control; 1120 uarg->callback(uarg, false); 1121 } 1122 } 1123 1124 if (err) { 1125 tun->dev->stats.rx_dropped++; 1126 kfree_skb(skb); 1127 return -EFAULT; 1128 } 1129 1130 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 1131 if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start), 1132 tun16_to_cpu(tun, gso.csum_offset))) { 1133 tun->dev->stats.rx_frame_errors++; 1134 kfree_skb(skb); 1135 return -EINVAL; 1136 } 1137 } 1138 1139 switch (tun->flags & TUN_TYPE_MASK) { 1140 case IFF_TUN: 1141 if (tun->flags & IFF_NO_PI) { 1142 switch (skb->data[0] & 0xf0) { 1143 case 0x40: 1144 pi.proto = htons(ETH_P_IP); 1145 break; 1146 case 0x60: 1147 pi.proto = htons(ETH_P_IPV6); 1148 break; 1149 default: 1150 tun->dev->stats.rx_dropped++; 1151 kfree_skb(skb); 1152 return -EINVAL; 1153 } 1154 } 1155 1156 skb_reset_mac_header(skb); 1157 skb->protocol = pi.proto; 1158 skb->dev = tun->dev; 1159 break; 1160 case IFF_TAP: 1161 skb->protocol = eth_type_trans(skb, tun->dev); 1162 break; 1163 } 1164 1165 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 1166 pr_debug("GSO!\n"); 1167 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 1168 case VIRTIO_NET_HDR_GSO_TCPV4: 1169 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1170 break; 1171 case VIRTIO_NET_HDR_GSO_TCPV6: 1172 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1173 break; 1174 case VIRTIO_NET_HDR_GSO_UDP: 1175 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 1176 break; 1177 default: 1178 tun->dev->stats.rx_frame_errors++; 1179 kfree_skb(skb); 1180 return -EINVAL; 1181 } 1182 1183 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 1184 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 1185 1186 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size); 1187 if (skb_shinfo(skb)->gso_size == 0) { 1188 tun->dev->stats.rx_frame_errors++; 1189 kfree_skb(skb); 1190 return -EINVAL; 1191 } 1192 1193 /* Header must be checked, and gso_segs computed. */ 1194 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 1195 skb_shinfo(skb)->gso_segs = 0; 1196 } 1197 1198 /* copy skb_ubuf_info for callback when skb has no error */ 1199 if (zerocopy) { 1200 skb_shinfo(skb)->destructor_arg = msg_control; 1201 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 1202 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 1203 } 1204 1205 skb_reset_network_header(skb); 1206 skb_probe_transport_header(skb, 0); 1207 1208 rxhash = skb_get_hash(skb); 1209 netif_rx_ni(skb); 1210 1211 tun->dev->stats.rx_packets++; 1212 tun->dev->stats.rx_bytes += len; 1213 1214 tun_flow_update(tun, rxhash, tfile); 1215 return total_len; 1216} 1217 1218static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from) 1219{ 1220 struct file *file = iocb->ki_filp; 1221 struct tun_struct *tun = tun_get(file); 1222 struct tun_file *tfile = file->private_data; 1223 ssize_t result; 1224 1225 if (!tun) 1226 return -EBADFD; 1227 1228 result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK); 1229 1230 tun_put(tun); 1231 return result; 1232} 1233 1234/* Put packet to the user space buffer */ 1235static ssize_t tun_put_user(struct tun_struct *tun, 1236 struct tun_file *tfile, 1237 struct sk_buff *skb, 1238 struct iov_iter *iter) 1239{ 1240 struct tun_pi pi = { 0, skb->protocol }; 1241 ssize_t total; 1242 int vlan_offset = 0; 1243 int vlan_hlen = 0; 1244 int vnet_hdr_sz = 0; 1245 1246 if (skb_vlan_tag_present(skb)) 1247 vlan_hlen = VLAN_HLEN; 1248 1249 if (tun->flags & IFF_VNET_HDR) 1250 vnet_hdr_sz = tun->vnet_hdr_sz; 1251 1252 total = skb->len + vlan_hlen + vnet_hdr_sz; 1253 1254 if (!(tun->flags & IFF_NO_PI)) { 1255 if (iov_iter_count(iter) < sizeof(pi)) 1256 return -EINVAL; 1257 1258 total += sizeof(pi); 1259 if (iov_iter_count(iter) < total) { 1260 /* Packet will be striped */ 1261 pi.flags |= TUN_PKT_STRIP; 1262 } 1263 1264 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi)) 1265 return -EFAULT; 1266 } 1267 1268 if (vnet_hdr_sz) { 1269 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 1270 if (iov_iter_count(iter) < vnet_hdr_sz) 1271 return -EINVAL; 1272 1273 if (skb_is_gso(skb)) { 1274 struct skb_shared_info *sinfo = skb_shinfo(skb); 1275 1276 /* This is a hint as to how much should be linear. */ 1277 gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb)); 1278 gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size); 1279 if (sinfo->gso_type & SKB_GSO_TCPV4) 1280 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 1281 else if (sinfo->gso_type & SKB_GSO_TCPV6) 1282 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 1283 else if (sinfo->gso_type & SKB_GSO_UDP) 1284 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 1285 else { 1286 pr_err("unexpected GSO type: " 1287 "0x%x, gso_size %d, hdr_len %d\n", 1288 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size), 1289 tun16_to_cpu(tun, gso.hdr_len)); 1290 print_hex_dump(KERN_ERR, "tun: ", 1291 DUMP_PREFIX_NONE, 1292 16, 1, skb->head, 1293 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true); 1294 WARN_ON_ONCE(1); 1295 return -EINVAL; 1296 } 1297 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 1298 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 1299 } else 1300 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 1301 1302 if (skb->ip_summed == CHECKSUM_PARTIAL) { 1303 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 1304 gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) + 1305 vlan_hlen); 1306 gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset); 1307 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 1308 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 1309 } /* else everything is zero */ 1310 1311 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso)) 1312 return -EFAULT; 1313 1314 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso)); 1315 } 1316 1317 if (vlan_hlen) { 1318 int ret; 1319 struct { 1320 __be16 h_vlan_proto; 1321 __be16 h_vlan_TCI; 1322 } veth; 1323 1324 veth.h_vlan_proto = skb->vlan_proto; 1325 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb)); 1326 1327 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 1328 1329 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset); 1330 if (ret || !iov_iter_count(iter)) 1331 goto done; 1332 1333 ret = copy_to_iter(&veth, sizeof(veth), iter); 1334 if (ret != sizeof(veth) || !iov_iter_count(iter)) 1335 goto done; 1336 } 1337 1338 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset); 1339 1340done: 1341 tun->dev->stats.tx_packets++; 1342 tun->dev->stats.tx_bytes += skb->len + vlan_hlen; 1343 1344 return total; 1345} 1346 1347static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 1348 struct iov_iter *to, 1349 int noblock) 1350{ 1351 struct sk_buff *skb; 1352 ssize_t ret; 1353 int peeked, err, off = 0; 1354 1355 tun_debug(KERN_INFO, tun, "tun_do_read\n"); 1356 1357 if (!iov_iter_count(to)) 1358 return 0; 1359 1360 if (tun->dev->reg_state != NETREG_REGISTERED) 1361 return -EIO; 1362 1363 /* Read frames from queue */ 1364 skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0, 1365 &peeked, &off, &err); 1366 if (!skb) 1367 return err; 1368 1369 ret = tun_put_user(tun, tfile, skb, to); 1370 if (unlikely(ret < 0)) 1371 kfree_skb(skb); 1372 else 1373 consume_skb(skb); 1374 1375 return ret; 1376} 1377 1378static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1379{ 1380 struct file *file = iocb->ki_filp; 1381 struct tun_file *tfile = file->private_data; 1382 struct tun_struct *tun = __tun_get(tfile); 1383 ssize_t len = iov_iter_count(to), ret; 1384 1385 if (!tun) 1386 return -EBADFD; 1387 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK); 1388 ret = min_t(ssize_t, ret, len); 1389 if (ret > 0) 1390 iocb->ki_pos = ret; 1391 tun_put(tun); 1392 return ret; 1393} 1394 1395static void tun_free_netdev(struct net_device *dev) 1396{ 1397 struct tun_struct *tun = netdev_priv(dev); 1398 1399 BUG_ON(!(list_empty(&tun->disabled))); 1400 tun_flow_uninit(tun); 1401 security_tun_dev_free_security(tun->security); 1402 free_netdev(dev); 1403} 1404 1405static void tun_setup(struct net_device *dev) 1406{ 1407 struct tun_struct *tun = netdev_priv(dev); 1408 1409 tun->owner = INVALID_UID; 1410 tun->group = INVALID_GID; 1411 1412 dev->ethtool_ops = &tun_ethtool_ops; 1413 dev->destructor = tun_free_netdev; 1414} 1415 1416/* Trivial set of netlink ops to allow deleting tun or tap 1417 * device with netlink. 1418 */ 1419static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1420{ 1421 return -EINVAL; 1422} 1423 1424static struct rtnl_link_ops tun_link_ops __read_mostly = { 1425 .kind = DRV_NAME, 1426 .priv_size = sizeof(struct tun_struct), 1427 .setup = tun_setup, 1428 .validate = tun_validate, 1429}; 1430 1431static void tun_sock_write_space(struct sock *sk) 1432{ 1433 struct tun_file *tfile; 1434 wait_queue_head_t *wqueue; 1435 1436 if (!sock_writeable(sk)) 1437 return; 1438 1439 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1440 return; 1441 1442 wqueue = sk_sleep(sk); 1443 if (wqueue && waitqueue_active(wqueue)) 1444 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1445 POLLWRNORM | POLLWRBAND); 1446 1447 tfile = container_of(sk, struct tun_file, sk); 1448 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); 1449} 1450 1451static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) 1452{ 1453 int ret; 1454 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1455 struct tun_struct *tun = __tun_get(tfile); 1456 1457 if (!tun) 1458 return -EBADFD; 1459 1460 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter, 1461 m->msg_flags & MSG_DONTWAIT); 1462 tun_put(tun); 1463 return ret; 1464} 1465 1466static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, 1467 int flags) 1468{ 1469 struct tun_file *tfile = container_of(sock, struct tun_file, socket); 1470 struct tun_struct *tun = __tun_get(tfile); 1471 int ret; 1472 1473 if (!tun) 1474 return -EBADFD; 1475 1476 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { 1477 ret = -EINVAL; 1478 goto out; 1479 } 1480 if (flags & MSG_ERRQUEUE) { 1481 ret = sock_recv_errqueue(sock->sk, m, total_len, 1482 SOL_PACKET, TUN_TX_TIMESTAMP); 1483 goto out; 1484 } 1485 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT); 1486 if (ret > (ssize_t)total_len) { 1487 m->msg_flags |= MSG_TRUNC; 1488 ret = flags & MSG_TRUNC ? ret : total_len; 1489 } 1490out: 1491 tun_put(tun); 1492 return ret; 1493} 1494 1495static int tun_release(struct socket *sock) 1496{ 1497 if (sock->sk) 1498 sock_put(sock->sk); 1499 return 0; 1500} 1501 1502/* Ops structure to mimic raw sockets with tun */ 1503static const struct proto_ops tun_socket_ops = { 1504 .sendmsg = tun_sendmsg, 1505 .recvmsg = tun_recvmsg, 1506 .release = tun_release, 1507}; 1508 1509static struct proto tun_proto = { 1510 .name = "tun", 1511 .owner = THIS_MODULE, 1512 .obj_size = sizeof(struct tun_file), 1513}; 1514 1515static int tun_flags(struct tun_struct *tun) 1516{ 1517 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP); 1518} 1519 1520static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1521 char *buf) 1522{ 1523 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1524 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1525} 1526 1527static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1528 char *buf) 1529{ 1530 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1531 return uid_valid(tun->owner)? 1532 sprintf(buf, "%u\n", 1533 from_kuid_munged(current_user_ns(), tun->owner)): 1534 sprintf(buf, "-1\n"); 1535} 1536 1537static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1538 char *buf) 1539{ 1540 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1541 return gid_valid(tun->group) ? 1542 sprintf(buf, "%u\n", 1543 from_kgid_munged(current_user_ns(), tun->group)): 1544 sprintf(buf, "-1\n"); 1545} 1546 1547static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1548static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1549static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1550 1551static struct attribute *tun_dev_attrs[] = { 1552 &dev_attr_tun_flags.attr, 1553 &dev_attr_owner.attr, 1554 &dev_attr_group.attr, 1555 NULL 1556}; 1557 1558static const struct attribute_group tun_attr_group = { 1559 .attrs = tun_dev_attrs 1560}; 1561 1562static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1563{ 1564 struct tun_struct *tun; 1565 struct tun_file *tfile = file->private_data; 1566 struct net_device *dev; 1567 int err; 1568 1569 if (tfile->detached) 1570 return -EINVAL; 1571 1572 dev = __dev_get_by_name(net, ifr->ifr_name); 1573 if (dev) { 1574 if (ifr->ifr_flags & IFF_TUN_EXCL) 1575 return -EBUSY; 1576 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1577 tun = netdev_priv(dev); 1578 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1579 tun = netdev_priv(dev); 1580 else 1581 return -EINVAL; 1582 1583 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != 1584 !!(tun->flags & IFF_MULTI_QUEUE)) 1585 return -EINVAL; 1586 1587 if (tun_not_capable(tun)) 1588 return -EPERM; 1589 err = security_tun_dev_open(tun->security); 1590 if (err < 0) 1591 return err; 1592 1593 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); 1594 if (err < 0) 1595 return err; 1596 1597 if (tun->flags & IFF_MULTI_QUEUE && 1598 (tun->numqueues + tun->numdisabled > 1)) { 1599 /* One or more queue has already been attached, no need 1600 * to initialize the device again. 1601 */ 1602 return 0; 1603 } 1604 } 1605 else { 1606 char *name; 1607 unsigned long flags = 0; 1608 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? 1609 MAX_TAP_QUEUES : 1; 1610 1611 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1612 return -EPERM; 1613 err = security_tun_dev_create(); 1614 if (err < 0) 1615 return err; 1616 1617 /* Set dev type */ 1618 if (ifr->ifr_flags & IFF_TUN) { 1619 /* TUN device */ 1620 flags |= IFF_TUN; 1621 name = "tun%d"; 1622 } else if (ifr->ifr_flags & IFF_TAP) { 1623 /* TAP device */ 1624 flags |= IFF_TAP; 1625 name = "tap%d"; 1626 } else 1627 return -EINVAL; 1628 1629 if (*ifr->ifr_name) 1630 name = ifr->ifr_name; 1631 1632 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, 1633 NET_NAME_UNKNOWN, tun_setup, queues, 1634 queues); 1635 1636 if (!dev) 1637 return -ENOMEM; 1638 1639 dev_net_set(dev, net); 1640 dev->rtnl_link_ops = &tun_link_ops; 1641 dev->ifindex = tfile->ifindex; 1642 dev->sysfs_groups[0] = &tun_attr_group; 1643 1644 tun = netdev_priv(dev); 1645 tun->dev = dev; 1646 tun->flags = flags; 1647 tun->txflt.count = 0; 1648 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1649 1650 tun->filter_attached = false; 1651 tun->sndbuf = tfile->socket.sk->sk_sndbuf; 1652 1653 spin_lock_init(&tun->lock); 1654 1655 err = security_tun_dev_alloc_security(&tun->security); 1656 if (err < 0) 1657 goto err_free_dev; 1658 1659 tun_net_init(dev); 1660 tun_flow_init(tun); 1661 1662 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1663 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | 1664 NETIF_F_HW_VLAN_STAG_TX; 1665 dev->features = dev->hw_features; 1666 dev->vlan_features = dev->features & 1667 ~(NETIF_F_HW_VLAN_CTAG_TX | 1668 NETIF_F_HW_VLAN_STAG_TX); 1669 1670 INIT_LIST_HEAD(&tun->disabled); 1671 err = tun_attach(tun, file, false); 1672 if (err < 0) 1673 goto err_free_flow; 1674 1675 err = register_netdevice(tun->dev); 1676 if (err < 0) 1677 goto err_detach; 1678 } 1679 1680 netif_carrier_on(tun->dev); 1681 1682 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1683 1684 tun->flags = (tun->flags & ~TUN_FEATURES) | 1685 (ifr->ifr_flags & TUN_FEATURES); 1686 1687 /* Make sure persistent devices do not get stuck in 1688 * xoff state. 1689 */ 1690 if (netif_running(tun->dev)) 1691 netif_tx_wake_all_queues(tun->dev); 1692 1693 strcpy(ifr->ifr_name, tun->dev->name); 1694 return 0; 1695 1696err_detach: 1697 tun_detach_all(dev); 1698err_free_flow: 1699 tun_flow_uninit(tun); 1700 security_tun_dev_free_security(tun->security); 1701err_free_dev: 1702 free_netdev(dev); 1703 return err; 1704} 1705 1706static void tun_get_iff(struct net *net, struct tun_struct *tun, 1707 struct ifreq *ifr) 1708{ 1709 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1710 1711 strcpy(ifr->ifr_name, tun->dev->name); 1712 1713 ifr->ifr_flags = tun_flags(tun); 1714 1715} 1716 1717/* This is like a cut-down ethtool ops, except done via tun fd so no 1718 * privs required. */ 1719static int set_offload(struct tun_struct *tun, unsigned long arg) 1720{ 1721 netdev_features_t features = 0; 1722 1723 if (arg & TUN_F_CSUM) { 1724 features |= NETIF_F_HW_CSUM; 1725 arg &= ~TUN_F_CSUM; 1726 1727 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1728 if (arg & TUN_F_TSO_ECN) { 1729 features |= NETIF_F_TSO_ECN; 1730 arg &= ~TUN_F_TSO_ECN; 1731 } 1732 if (arg & TUN_F_TSO4) 1733 features |= NETIF_F_TSO; 1734 if (arg & TUN_F_TSO6) 1735 features |= NETIF_F_TSO6; 1736 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1737 } 1738 1739 if (arg & TUN_F_UFO) { 1740 features |= NETIF_F_UFO; 1741 arg &= ~TUN_F_UFO; 1742 } 1743 } 1744 1745 /* This gives the user a way to test for new features in future by 1746 * trying to set them. */ 1747 if (arg) 1748 return -EINVAL; 1749 1750 tun->set_features = features; 1751 netdev_update_features(tun->dev); 1752 1753 return 0; 1754} 1755 1756static void tun_detach_filter(struct tun_struct *tun, int n) 1757{ 1758 int i; 1759 struct tun_file *tfile; 1760 1761 for (i = 0; i < n; i++) { 1762 tfile = rtnl_dereference(tun->tfiles[i]); 1763 sk_detach_filter(tfile->socket.sk); 1764 } 1765 1766 tun->filter_attached = false; 1767} 1768 1769static int tun_attach_filter(struct tun_struct *tun) 1770{ 1771 int i, ret = 0; 1772 struct tun_file *tfile; 1773 1774 for (i = 0; i < tun->numqueues; i++) { 1775 tfile = rtnl_dereference(tun->tfiles[i]); 1776 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk); 1777 if (ret) { 1778 tun_detach_filter(tun, i); 1779 return ret; 1780 } 1781 } 1782 1783 tun->filter_attached = true; 1784 return ret; 1785} 1786 1787static void tun_set_sndbuf(struct tun_struct *tun) 1788{ 1789 struct tun_file *tfile; 1790 int i; 1791 1792 for (i = 0; i < tun->numqueues; i++) { 1793 tfile = rtnl_dereference(tun->tfiles[i]); 1794 tfile->socket.sk->sk_sndbuf = tun->sndbuf; 1795 } 1796} 1797 1798static int tun_set_queue(struct file *file, struct ifreq *ifr) 1799{ 1800 struct tun_file *tfile = file->private_data; 1801 struct tun_struct *tun; 1802 int ret = 0; 1803 1804 rtnl_lock(); 1805 1806 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { 1807 tun = tfile->detached; 1808 if (!tun) { 1809 ret = -EINVAL; 1810 goto unlock; 1811 } 1812 ret = security_tun_dev_attach_queue(tun->security); 1813 if (ret < 0) 1814 goto unlock; 1815 ret = tun_attach(tun, file, false); 1816 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { 1817 tun = rtnl_dereference(tfile->tun); 1818 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached) 1819 ret = -EINVAL; 1820 else 1821 __tun_detach(tfile, false); 1822 } else 1823 ret = -EINVAL; 1824 1825unlock: 1826 rtnl_unlock(); 1827 return ret; 1828} 1829 1830static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1831 unsigned long arg, int ifreq_len) 1832{ 1833 struct tun_file *tfile = file->private_data; 1834 struct tun_struct *tun; 1835 void __user* argp = (void __user*)arg; 1836 struct ifreq ifr; 1837 kuid_t owner; 1838 kgid_t group; 1839 int sndbuf; 1840 int vnet_hdr_sz; 1841 unsigned int ifindex; 1842 int le; 1843 int ret; 1844 1845 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 1846 if (copy_from_user(&ifr, argp, ifreq_len)) 1847 return -EFAULT; 1848 } else { 1849 memset(&ifr, 0, sizeof(ifr)); 1850 } 1851 if (cmd == TUNGETFEATURES) { 1852 /* Currently this just means: "what IFF flags are valid?". 1853 * This is needed because we never checked for invalid flags on 1854 * TUNSETIFF. 1855 */ 1856 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES, 1857 (unsigned int __user*)argp); 1858 } else if (cmd == TUNSETQUEUE) 1859 return tun_set_queue(file, &ifr); 1860 1861 ret = 0; 1862 rtnl_lock(); 1863 1864 tun = __tun_get(tfile); 1865 if (cmd == TUNSETIFF && !tun) { 1866 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1867 1868 ret = tun_set_iff(tfile->net, file, &ifr); 1869 1870 if (ret) 1871 goto unlock; 1872 1873 if (copy_to_user(argp, &ifr, ifreq_len)) 1874 ret = -EFAULT; 1875 goto unlock; 1876 } 1877 if (cmd == TUNSETIFINDEX) { 1878 ret = -EPERM; 1879 if (tun) 1880 goto unlock; 1881 1882 ret = -EFAULT; 1883 if (copy_from_user(&ifindex, argp, sizeof(ifindex))) 1884 goto unlock; 1885 1886 ret = 0; 1887 tfile->ifindex = ifindex; 1888 goto unlock; 1889 } 1890 1891 ret = -EBADFD; 1892 if (!tun) 1893 goto unlock; 1894 1895 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); 1896 1897 ret = 0; 1898 switch (cmd) { 1899 case TUNGETIFF: 1900 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1901 1902 if (tfile->detached) 1903 ifr.ifr_flags |= IFF_DETACH_QUEUE; 1904 if (!tfile->socket.sk->sk_filter) 1905 ifr.ifr_flags |= IFF_NOFILTER; 1906 1907 if (copy_to_user(argp, &ifr, ifreq_len)) 1908 ret = -EFAULT; 1909 break; 1910 1911 case TUNSETNOCSUM: 1912 /* Disable/Enable checksum */ 1913 1914 /* [unimplemented] */ 1915 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1916 arg ? "disabled" : "enabled"); 1917 break; 1918 1919 case TUNSETPERSIST: 1920 /* Disable/Enable persist mode. Keep an extra reference to the 1921 * module to prevent the module being unprobed. 1922 */ 1923 if (arg && !(tun->flags & IFF_PERSIST)) { 1924 tun->flags |= IFF_PERSIST; 1925 __module_get(THIS_MODULE); 1926 } 1927 if (!arg && (tun->flags & IFF_PERSIST)) { 1928 tun->flags &= ~IFF_PERSIST; 1929 module_put(THIS_MODULE); 1930 } 1931 1932 tun_debug(KERN_INFO, tun, "persist %s\n", 1933 arg ? "enabled" : "disabled"); 1934 break; 1935 1936 case TUNSETOWNER: 1937 /* Set owner of the device */ 1938 owner = make_kuid(current_user_ns(), arg); 1939 if (!uid_valid(owner)) { 1940 ret = -EINVAL; 1941 break; 1942 } 1943 tun->owner = owner; 1944 tun_debug(KERN_INFO, tun, "owner set to %u\n", 1945 from_kuid(&init_user_ns, tun->owner)); 1946 break; 1947 1948 case TUNSETGROUP: 1949 /* Set group of the device */ 1950 group = make_kgid(current_user_ns(), arg); 1951 if (!gid_valid(group)) { 1952 ret = -EINVAL; 1953 break; 1954 } 1955 tun->group = group; 1956 tun_debug(KERN_INFO, tun, "group set to %u\n", 1957 from_kgid(&init_user_ns, tun->group)); 1958 break; 1959 1960 case TUNSETLINK: 1961 /* Only allow setting the type when the interface is down */ 1962 if (tun->dev->flags & IFF_UP) { 1963 tun_debug(KERN_INFO, tun, 1964 "Linktype set failed because interface is up\n"); 1965 ret = -EBUSY; 1966 } else { 1967 tun->dev->type = (int) arg; 1968 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1969 tun->dev->type); 1970 ret = 0; 1971 } 1972 break; 1973 1974#ifdef TUN_DEBUG 1975 case TUNSETDEBUG: 1976 tun->debug = arg; 1977 break; 1978#endif 1979 case TUNSETOFFLOAD: 1980 ret = set_offload(tun, arg); 1981 break; 1982 1983 case TUNSETTXFILTER: 1984 /* Can be set only for TAPs */ 1985 ret = -EINVAL; 1986 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 1987 break; 1988 ret = update_filter(&tun->txflt, (void __user *)arg); 1989 break; 1990 1991 case SIOCGIFHWADDR: 1992 /* Get hw address */ 1993 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 1994 ifr.ifr_hwaddr.sa_family = tun->dev->type; 1995 if (copy_to_user(argp, &ifr, ifreq_len)) 1996 ret = -EFAULT; 1997 break; 1998 1999 case SIOCSIFHWADDR: 2000 /* Set hw address */ 2001 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 2002 ifr.ifr_hwaddr.sa_data); 2003 2004 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 2005 break; 2006 2007 case TUNGETSNDBUF: 2008 sndbuf = tfile->socket.sk->sk_sndbuf; 2009 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 2010 ret = -EFAULT; 2011 break; 2012 2013 case TUNSETSNDBUF: 2014 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 2015 ret = -EFAULT; 2016 break; 2017 } 2018 2019 tun->sndbuf = sndbuf; 2020 tun_set_sndbuf(tun); 2021 break; 2022 2023 case TUNGETVNETHDRSZ: 2024 vnet_hdr_sz = tun->vnet_hdr_sz; 2025 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 2026 ret = -EFAULT; 2027 break; 2028 2029 case TUNSETVNETHDRSZ: 2030 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 2031 ret = -EFAULT; 2032 break; 2033 } 2034 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 2035 ret = -EINVAL; 2036 break; 2037 } 2038 2039 tun->vnet_hdr_sz = vnet_hdr_sz; 2040 break; 2041 2042 case TUNGETVNETLE: 2043 le = !!(tun->flags & TUN_VNET_LE); 2044 if (put_user(le, (int __user *)argp)) 2045 ret = -EFAULT; 2046 break; 2047 2048 case TUNSETVNETLE: 2049 if (get_user(le, (int __user *)argp)) { 2050 ret = -EFAULT; 2051 break; 2052 } 2053 if (le) 2054 tun->flags |= TUN_VNET_LE; 2055 else 2056 tun->flags &= ~TUN_VNET_LE; 2057 break; 2058 2059 case TUNATTACHFILTER: 2060 /* Can be set only for TAPs */ 2061 ret = -EINVAL; 2062 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2063 break; 2064 ret = -EFAULT; 2065 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog))) 2066 break; 2067 2068 ret = tun_attach_filter(tun); 2069 break; 2070 2071 case TUNDETACHFILTER: 2072 /* Can be set only for TAPs */ 2073 ret = -EINVAL; 2074 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2075 break; 2076 ret = 0; 2077 tun_detach_filter(tun, tun->numqueues); 2078 break; 2079 2080 case TUNGETFILTER: 2081 ret = -EINVAL; 2082 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) 2083 break; 2084 ret = -EFAULT; 2085 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) 2086 break; 2087 ret = 0; 2088 break; 2089 2090 default: 2091 ret = -EINVAL; 2092 break; 2093 } 2094 2095unlock: 2096 rtnl_unlock(); 2097 if (tun) 2098 tun_put(tun); 2099 return ret; 2100} 2101 2102static long tun_chr_ioctl(struct file *file, 2103 unsigned int cmd, unsigned long arg) 2104{ 2105 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 2106} 2107 2108#ifdef CONFIG_COMPAT 2109static long tun_chr_compat_ioctl(struct file *file, 2110 unsigned int cmd, unsigned long arg) 2111{ 2112 switch (cmd) { 2113 case TUNSETIFF: 2114 case TUNGETIFF: 2115 case TUNSETTXFILTER: 2116 case TUNGETSNDBUF: 2117 case TUNSETSNDBUF: 2118 case SIOCGIFHWADDR: 2119 case SIOCSIFHWADDR: 2120 arg = (unsigned long)compat_ptr(arg); 2121 break; 2122 default: 2123 arg = (compat_ulong_t)arg; 2124 break; 2125 } 2126 2127 /* 2128 * compat_ifreq is shorter than ifreq, so we must not access beyond 2129 * the end of that structure. All fields that are used in this 2130 * driver are compatible though, we don't need to convert the 2131 * contents. 2132 */ 2133 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 2134} 2135#endif /* CONFIG_COMPAT */ 2136 2137static int tun_chr_fasync(int fd, struct file *file, int on) 2138{ 2139 struct tun_file *tfile = file->private_data; 2140 int ret; 2141 2142 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) 2143 goto out; 2144 2145 if (on) { 2146 __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 2147 tfile->flags |= TUN_FASYNC; 2148 } else 2149 tfile->flags &= ~TUN_FASYNC; 2150 ret = 0; 2151out: 2152 return ret; 2153} 2154 2155static int tun_chr_open(struct inode *inode, struct file * file) 2156{ 2157 struct tun_file *tfile; 2158 2159 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 2160 2161 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, 2162 &tun_proto); 2163 if (!tfile) 2164 return -ENOMEM; 2165 RCU_INIT_POINTER(tfile->tun, NULL); 2166 tfile->net = get_net(current->nsproxy->net_ns); 2167 tfile->flags = 0; 2168 tfile->ifindex = 0; 2169 2170 init_waitqueue_head(&tfile->wq.wait); 2171 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq); 2172 2173 tfile->socket.file = file; 2174 tfile->socket.ops = &tun_socket_ops; 2175 2176 sock_init_data(&tfile->socket, &tfile->sk); 2177 sk_change_net(&tfile->sk, tfile->net); 2178 2179 tfile->sk.sk_write_space = tun_sock_write_space; 2180 tfile->sk.sk_sndbuf = INT_MAX; 2181 2182 file->private_data = tfile; 2183 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 2184 INIT_LIST_HEAD(&tfile->next); 2185 2186 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); 2187 2188 return 0; 2189} 2190 2191static int tun_chr_close(struct inode *inode, struct file *file) 2192{ 2193 struct tun_file *tfile = file->private_data; 2194 struct net *net = tfile->net; 2195 2196 tun_detach(tfile, true); 2197 put_net(net); 2198 2199 return 0; 2200} 2201 2202#ifdef CONFIG_PROC_FS 2203static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f) 2204{ 2205 struct tun_struct *tun; 2206 struct ifreq ifr; 2207 2208 memset(&ifr, 0, sizeof(ifr)); 2209 2210 rtnl_lock(); 2211 tun = tun_get(f); 2212 if (tun) 2213 tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 2214 rtnl_unlock(); 2215 2216 if (tun) 2217 tun_put(tun); 2218 2219 seq_printf(m, "iff:\t%s\n", ifr.ifr_name); 2220} 2221#endif 2222 2223static const struct file_operations tun_fops = { 2224 .owner = THIS_MODULE, 2225 .llseek = no_llseek, 2226 .read_iter = tun_chr_read_iter, 2227 .write_iter = tun_chr_write_iter, 2228 .poll = tun_chr_poll, 2229 .unlocked_ioctl = tun_chr_ioctl, 2230#ifdef CONFIG_COMPAT 2231 .compat_ioctl = tun_chr_compat_ioctl, 2232#endif 2233 .open = tun_chr_open, 2234 .release = tun_chr_close, 2235 .fasync = tun_chr_fasync, 2236#ifdef CONFIG_PROC_FS 2237 .show_fdinfo = tun_chr_show_fdinfo, 2238#endif 2239}; 2240 2241static struct miscdevice tun_miscdev = { 2242 .minor = TUN_MINOR, 2243 .name = "tun", 2244 .nodename = "net/tun", 2245 .fops = &tun_fops, 2246}; 2247 2248/* ethtool interface */ 2249 2250static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 2251{ 2252 cmd->supported = 0; 2253 cmd->advertising = 0; 2254 ethtool_cmd_speed_set(cmd, SPEED_10); 2255 cmd->duplex = DUPLEX_FULL; 2256 cmd->port = PORT_TP; 2257 cmd->phy_address = 0; 2258 cmd->transceiver = XCVR_INTERNAL; 2259 cmd->autoneg = AUTONEG_DISABLE; 2260 cmd->maxtxpkt = 0; 2261 cmd->maxrxpkt = 0; 2262 return 0; 2263} 2264 2265static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 2266{ 2267 struct tun_struct *tun = netdev_priv(dev); 2268 2269 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 2270 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 2271 2272 switch (tun->flags & TUN_TYPE_MASK) { 2273 case IFF_TUN: 2274 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 2275 break; 2276 case IFF_TAP: 2277 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 2278 break; 2279 } 2280} 2281 2282static u32 tun_get_msglevel(struct net_device *dev) 2283{ 2284#ifdef TUN_DEBUG 2285 struct tun_struct *tun = netdev_priv(dev); 2286 return tun->debug; 2287#else 2288 return -EOPNOTSUPP; 2289#endif 2290} 2291 2292static void tun_set_msglevel(struct net_device *dev, u32 value) 2293{ 2294#ifdef TUN_DEBUG 2295 struct tun_struct *tun = netdev_priv(dev); 2296 tun->debug = value; 2297#endif 2298} 2299 2300static const struct ethtool_ops tun_ethtool_ops = { 2301 .get_settings = tun_get_settings, 2302 .get_drvinfo = tun_get_drvinfo, 2303 .get_msglevel = tun_get_msglevel, 2304 .set_msglevel = tun_set_msglevel, 2305 .get_link = ethtool_op_get_link, 2306 .get_ts_info = ethtool_op_get_ts_info, 2307}; 2308 2309 2310static int __init tun_init(void) 2311{ 2312 int ret = 0; 2313 2314 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 2315 pr_info("%s\n", DRV_COPYRIGHT); 2316 2317 ret = rtnl_link_register(&tun_link_ops); 2318 if (ret) { 2319 pr_err("Can't register link_ops\n"); 2320 goto err_linkops; 2321 } 2322 2323 ret = misc_register(&tun_miscdev); 2324 if (ret) { 2325 pr_err("Can't register misc device %d\n", TUN_MINOR); 2326 goto err_misc; 2327 } 2328 return 0; 2329err_misc: 2330 rtnl_link_unregister(&tun_link_ops); 2331err_linkops: 2332 return ret; 2333} 2334 2335static void tun_cleanup(void) 2336{ 2337 misc_deregister(&tun_miscdev); 2338 rtnl_link_unregister(&tun_link_ops); 2339} 2340 2341/* Get an underlying socket object from tun file. Returns error unless file is 2342 * attached to a device. The returned object works like a packet socket, it 2343 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 2344 * holding a reference to the file for as long as the socket is in use. */ 2345struct socket *tun_get_socket(struct file *file) 2346{ 2347 struct tun_file *tfile; 2348 if (file->f_op != &tun_fops) 2349 return ERR_PTR(-EINVAL); 2350 tfile = file->private_data; 2351 if (!tfile) 2352 return ERR_PTR(-EBADFD); 2353 return &tfile->socket; 2354} 2355EXPORT_SYMBOL_GPL(tun_get_socket); 2356 2357module_init(tun_init); 2358module_exit(tun_cleanup); 2359MODULE_DESCRIPTION(DRV_DESCRIPTION); 2360MODULE_AUTHOR(DRV_COPYRIGHT); 2361MODULE_LICENSE("GPL"); 2362MODULE_ALIAS_MISCDEV(TUN_MINOR); 2363MODULE_ALIAS("devname:net/tun"); 2364