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#define TUN_VNET_BE     0x40000000
 115
 116#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
 117		      IFF_MULTI_QUEUE)
 
 118#define GOODCOPY_LEN 128
 119
 120#define FLT_EXACT_COUNT 8
 121struct tap_filter {
 122	unsigned int    count;    /* Number of addrs. Zero means disabled */
 123	u32             mask[2];  /* Mask of the hashed addrs */
 124	unsigned char	addr[FLT_EXACT_COUNT][ETH_ALEN];
 125};
 126
 127/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
 128 * to max number of VCPUs in guest. */
 129#define MAX_TAP_QUEUES 256
 130#define MAX_TAP_FLOWS  4096
 131
 132#define TUN_FLOW_EXPIRE (3 * HZ)
 133
 134/* A tun_file connects an open character device to a tuntap netdevice. It
 135 * also contains all socket related structures (except sock_fprog and tap_filter)
 136 * to serve as one transmit queue for tuntap device. The sock_fprog and
 137 * tap_filter were kept in tun_struct since they were used for filtering for the
 138 * netdevice not for a specific queue (at least I didn't see the requirement for
 139 * this).
 140 *
 141 * RCU usage:
 142 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
 143 * other can only be read while rcu_read_lock or rtnl_lock is held.
 144 */
 145struct tun_file {
 146	struct sock sk;
 147	struct socket socket;
 148	struct socket_wq wq;
 149	struct tun_struct __rcu *tun;
 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			align;
 191	int			vnet_hdr_sz;
 192	int			sndbuf;
 193	struct tap_filter	txflt;
 194	struct sock_fprog	fprog;
 195	/* protected by rtnl lock */
 196	bool			filter_attached;
 197#ifdef TUN_DEBUG
 198	int debug;
 199#endif
 200	spinlock_t lock;
 201	struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
 202	struct timer_list flow_gc_timer;
 203	unsigned long ageing_time;
 204	unsigned int numdisabled;
 205	struct list_head disabled;
 206	void *security;
 207	u32 flow_count;
 
 
 
 
 
 
 
 
 
 208};
 209
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 210#ifdef CONFIG_TUN_VNET_CROSS_LE
 211static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 212{
 213	return tun->flags & TUN_VNET_BE ? false :
 214		virtio_legacy_is_little_endian();
 215}
 216
 217static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 218{
 219	int be = !!(tun->flags & TUN_VNET_BE);
 220
 221	if (put_user(be, argp))
 222		return -EFAULT;
 223
 224	return 0;
 225}
 226
 227static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 228{
 229	int be;
 230
 231	if (get_user(be, argp))
 232		return -EFAULT;
 233
 234	if (be)
 235		tun->flags |= TUN_VNET_BE;
 236	else
 237		tun->flags &= ~TUN_VNET_BE;
 238
 239	return 0;
 240}
 241#else
 242static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
 243{
 244	return virtio_legacy_is_little_endian();
 245}
 246
 247static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 248{
 249	return -EINVAL;
 250}
 251
 252static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 253{
 254	return -EINVAL;
 255}
 256#endif /* CONFIG_TUN_VNET_CROSS_LE */
 257
 258static inline bool tun_is_little_endian(struct tun_struct *tun)
 259{
 260	return tun->flags & TUN_VNET_LE ||
 261		tun_legacy_is_little_endian(tun);
 262}
 263
 264static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
 265{
 266	return __virtio16_to_cpu(tun_is_little_endian(tun), val);
 267}
 268
 269static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
 270{
 271	return __cpu_to_virtio16(tun_is_little_endian(tun), val);
 272}
 273
 274static inline u32 tun_hashfn(u32 rxhash)
 275{
 276	return rxhash & 0x3ff;
 277}
 278
 279static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
 280{
 281	struct tun_flow_entry *e;
 282
 283	hlist_for_each_entry_rcu(e, head, hash_link) {
 284		if (e->rxhash == rxhash)
 285			return e;
 286	}
 287	return NULL;
 288}
 289
 290static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
 291					      struct hlist_head *head,
 292					      u32 rxhash, u16 queue_index)
 293{
 294	struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
 295
 296	if (e) {
 297		tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
 298			  rxhash, queue_index);
 
 299		e->updated = jiffies;
 300		e->rxhash = rxhash;
 301		e->rps_rxhash = 0;
 302		e->queue_index = queue_index;
 303		e->tun = tun;
 304		hlist_add_head_rcu(&e->hash_link, head);
 305		++tun->flow_count;
 306	}
 307	return e;
 308}
 309
 310static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
 311{
 312	tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
 313		  e->rxhash, e->queue_index);
 314	hlist_del_rcu(&e->hash_link);
 315	kfree_rcu(e, rcu);
 316	--tun->flow_count;
 317}
 318
 319static void tun_flow_flush(struct tun_struct *tun)
 320{
 321	int i;
 322
 323	spin_lock_bh(&tun->lock);
 324	for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 325		struct tun_flow_entry *e;
 326		struct hlist_node *n;
 327
 328		hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
 329			tun_flow_delete(tun, e);
 330	}
 331	spin_unlock_bh(&tun->lock);
 332}
 333
 334static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
 335{
 336	int i;
 337
 338	spin_lock_bh(&tun->lock);
 339	for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 340		struct tun_flow_entry *e;
 341		struct hlist_node *n;
 342
 343		hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 344			if (e->queue_index == queue_index)
 345				tun_flow_delete(tun, e);
 346		}
 347	}
 348	spin_unlock_bh(&tun->lock);
 349}
 350
 351static void tun_flow_cleanup(unsigned long data)
 352{
 353	struct tun_struct *tun = (struct tun_struct *)data;
 354	unsigned long delay = tun->ageing_time;
 355	unsigned long next_timer = jiffies + delay;
 356	unsigned long count = 0;
 357	int i;
 358
 359	tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
 360
 361	spin_lock_bh(&tun->lock);
 362	for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
 363		struct tun_flow_entry *e;
 364		struct hlist_node *n;
 365
 366		hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
 367			unsigned long this_timer;
 368			count++;
 369			this_timer = e->updated + delay;
 370			if (time_before_eq(this_timer, jiffies))
 371				tun_flow_delete(tun, e);
 372			else if (time_before(this_timer, next_timer))
 
 
 
 373				next_timer = this_timer;
 374		}
 375	}
 376
 377	if (count)
 378		mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
 379	spin_unlock_bh(&tun->lock);
 380}
 381
 382static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
 383			    struct tun_file *tfile)
 384{
 385	struct hlist_head *head;
 386	struct tun_flow_entry *e;
 387	unsigned long delay = tun->ageing_time;
 388	u16 queue_index = tfile->queue_index;
 389
 390	if (!rxhash)
 391		return;
 392	else
 393		head = &tun->flows[tun_hashfn(rxhash)];
 394
 395	rcu_read_lock();
 396
 397	/* We may get a very small possibility of OOO during switching, not
 398	 * worth to optimize.*/
 399	if (tun->numqueues == 1 || tfile->detached)
 400		goto unlock;
 401
 402	e = tun_flow_find(head, rxhash);
 403	if (likely(e)) {
 404		/* TODO: keep queueing to old queue until it's empty? */
 405		e->queue_index = queue_index;
 406		e->updated = jiffies;
 
 
 407		sock_rps_record_flow_hash(e->rps_rxhash);
 408	} else {
 409		spin_lock_bh(&tun->lock);
 410		if (!tun_flow_find(head, rxhash) &&
 411		    tun->flow_count < MAX_TAP_FLOWS)
 412			tun_flow_create(tun, head, rxhash, queue_index);
 413
 414		if (!timer_pending(&tun->flow_gc_timer))
 415			mod_timer(&tun->flow_gc_timer,
 416				  round_jiffies_up(jiffies + delay));
 417		spin_unlock_bh(&tun->lock);
 418	}
 419
 420unlock:
 421	rcu_read_unlock();
 422}
 423
 424/**
 425 * Save the hash received in the stack receive path and update the
 426 * flow_hash table accordingly.
 427 */
 428static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
 429{
 430	if (unlikely(e->rps_rxhash != hash))
 431		e->rps_rxhash = hash;
 432}
 433
 434/* We try to identify a flow through its rxhash first. The reason that
 435 * we do not check rxq no. is because some cards(e.g 82599), chooses
 436 * the rxq based on the txq where the last packet of the flow comes. As
 437 * the userspace application move between processors, we may get a
 438 * different rxq no. here. If we could not get rxhash, then we would
 439 * hope the rxq no. may help here.
 440 */
 441static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
 442			    void *accel_priv, select_queue_fallback_t fallback)
 443{
 444	struct tun_struct *tun = netdev_priv(dev);
 445	struct tun_flow_entry *e;
 446	u32 txq = 0;
 447	u32 numqueues = 0;
 448
 449	rcu_read_lock();
 450	numqueues = ACCESS_ONCE(tun->numqueues);
 451
 452	txq = skb_get_hash(skb);
 453	if (txq) {
 454		e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 455		if (e) {
 456			tun_flow_save_rps_rxhash(e, txq);
 457			txq = e->queue_index;
 458		} else
 459			/* use multiply and shift instead of expensive divide */
 460			txq = ((u64)txq * numqueues) >> 32;
 461	} else if (likely(skb_rx_queue_recorded(skb))) {
 462		txq = skb_get_rx_queue(skb);
 463		while (unlikely(txq >= numqueues))
 464			txq -= numqueues;
 465	}
 466
 467	rcu_read_unlock();
 468	return txq;
 469}
 470
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 471static inline bool tun_not_capable(struct tun_struct *tun)
 472{
 473	const struct cred *cred = current_cred();
 474	struct net *net = dev_net(tun->dev);
 475
 476	return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
 477		  (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
 478		!ns_capable(net->user_ns, CAP_NET_ADMIN);
 479}
 480
 481static void tun_set_real_num_queues(struct tun_struct *tun)
 482{
 483	netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
 484	netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 485}
 486
 487static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
 488{
 489	tfile->detached = tun;
 490	list_add_tail(&tfile->next, &tun->disabled);
 491	++tun->numdisabled;
 492}
 493
 494static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
 495{
 496	struct tun_struct *tun = tfile->detached;
 497
 498	tfile->detached = NULL;
 499	list_del_init(&tfile->next);
 500	--tun->numdisabled;
 501	return tun;
 502}
 503
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 504static void tun_queue_purge(struct tun_file *tfile)
 505{
 506	skb_queue_purge(&tfile->sk.sk_receive_queue);
 
 
 
 
 
 507	skb_queue_purge(&tfile->sk.sk_error_queue);
 508}
 509
 510static void __tun_detach(struct tun_file *tfile, bool clean)
 511{
 512	struct tun_file *ntfile;
 513	struct tun_struct *tun;
 514
 515	tun = rtnl_dereference(tfile->tun);
 516
 
 
 
 
 
 
 517	if (tun && !tfile->detached) {
 518		u16 index = tfile->queue_index;
 519		BUG_ON(index >= tun->numqueues);
 520
 521		rcu_assign_pointer(tun->tfiles[index],
 522				   tun->tfiles[tun->numqueues - 1]);
 523		ntfile = rtnl_dereference(tun->tfiles[index]);
 524		ntfile->queue_index = index;
 
 
 525
 526		--tun->numqueues;
 527		if (clean) {
 528			RCU_INIT_POINTER(tfile->tun, NULL);
 529			sock_put(&tfile->sk);
 530		} else
 531			tun_disable_queue(tun, tfile);
 
 
 532
 533		synchronize_net();
 534		tun_flow_delete_by_queue(tun, tun->numqueues + 1);
 535		/* Drop read queue */
 536		tun_queue_purge(tfile);
 537		tun_set_real_num_queues(tun);
 538	} else if (tfile->detached && clean) {
 539		tun = tun_enable_queue(tfile);
 540		sock_put(&tfile->sk);
 541	}
 542
 543	if (clean) {
 544		if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
 545			netif_carrier_off(tun->dev);
 546
 547			if (!(tun->flags & IFF_PERSIST) &&
 548			    tun->dev->reg_state == NETREG_REGISTERED)
 549				unregister_netdevice(tun->dev);
 550		}
 551		sock_put(&tfile->sk);
 
 
 552	}
 553}
 554
 555static void tun_detach(struct tun_file *tfile, bool clean)
 556{
 
 
 
 557	rtnl_lock();
 
 
 558	__tun_detach(tfile, clean);
 
 
 559	rtnl_unlock();
 
 
 
 560}
 561
 562static void tun_detach_all(struct net_device *dev)
 563{
 564	struct tun_struct *tun = netdev_priv(dev);
 565	struct tun_file *tfile, *tmp;
 566	int i, n = tun->numqueues;
 567
 568	for (i = 0; i < n; i++) {
 569		tfile = rtnl_dereference(tun->tfiles[i]);
 570		BUG_ON(!tfile);
 
 
 571		tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 572		RCU_INIT_POINTER(tfile->tun, NULL);
 573		--tun->numqueues;
 574	}
 575	list_for_each_entry(tfile, &tun->disabled, next) {
 
 576		tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 577		RCU_INIT_POINTER(tfile->tun, NULL);
 578	}
 579	BUG_ON(tun->numqueues != 0);
 580
 581	synchronize_net();
 582	for (i = 0; i < n; i++) {
 583		tfile = rtnl_dereference(tun->tfiles[i]);
 
 584		/* Drop read queue */
 585		tun_queue_purge(tfile);
 
 586		sock_put(&tfile->sk);
 587	}
 588	list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
 
 589		tun_enable_queue(tfile);
 590		tun_queue_purge(tfile);
 
 591		sock_put(&tfile->sk);
 592	}
 593	BUG_ON(tun->numdisabled != 0);
 594
 595	if (tun->flags & IFF_PERSIST)
 596		module_put(THIS_MODULE);
 597}
 598
 599static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
 
 
 600{
 601	struct tun_file *tfile = file->private_data;
 
 602	int err;
 603
 604	err = security_tun_dev_attach(tfile->socket.sk, tun->security);
 605	if (err < 0)
 606		goto out;
 607
 608	err = -EINVAL;
 609	if (rtnl_dereference(tfile->tun) && !tfile->detached)
 610		goto out;
 611
 612	err = -EBUSY;
 613	if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
 614		goto out;
 615
 616	err = -E2BIG;
 617	if (!tfile->detached &&
 618	    tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
 619		goto out;
 620
 621	err = 0;
 622
 623	/* Re-attach the filter to persist device */
 624	if (!skip_filter && (tun->filter_attached == true)) {
 625		err = __sk_attach_filter(&tun->fprog, tfile->socket.sk,
 626					 lockdep_rtnl_is_held());
 
 627		if (!err)
 628			goto out;
 629	}
 
 
 
 
 
 
 
 
 630	tfile->queue_index = tun->numqueues;
 631	rcu_assign_pointer(tfile->tun, tun);
 632	rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 633	tun->numqueues++;
 634
 635	if (tfile->detached)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 636		tun_enable_queue(tfile);
 637	else
 
 638		sock_hold(&tfile->sk);
 
 
 639
 640	tun_set_real_num_queues(tun);
 
 641
 642	/* device is allowed to go away first, so no need to hold extra
 643	 * refcnt.
 644	 */
 645
 
 
 
 
 
 
 
 
 
 646out:
 647	return err;
 648}
 649
 650static struct tun_struct *__tun_get(struct tun_file *tfile)
 651{
 652	struct tun_struct *tun;
 653
 654	rcu_read_lock();
 655	tun = rcu_dereference(tfile->tun);
 656	if (tun)
 657		dev_hold(tun->dev);
 658	rcu_read_unlock();
 659
 660	return tun;
 661}
 662
 663static struct tun_struct *tun_get(struct file *file)
 664{
 665	return __tun_get(file->private_data);
 666}
 667
 668static void tun_put(struct tun_struct *tun)
 669{
 670	dev_put(tun->dev);
 671}
 672
 673/* TAP filtering */
 674static void addr_hash_set(u32 *mask, const u8 *addr)
 675{
 676	int n = ether_crc(ETH_ALEN, addr) >> 26;
 677	mask[n >> 5] |= (1 << (n & 31));
 678}
 679
 680static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 681{
 682	int n = ether_crc(ETH_ALEN, addr) >> 26;
 683	return mask[n >> 5] & (1 << (n & 31));
 684}
 685
 686static int update_filter(struct tap_filter *filter, void __user *arg)
 687{
 688	struct { u8 u[ETH_ALEN]; } *addr;
 689	struct tun_filter uf;
 690	int err, alen, n, nexact;
 691
 692	if (copy_from_user(&uf, arg, sizeof(uf)))
 693		return -EFAULT;
 694
 695	if (!uf.count) {
 696		/* Disabled */
 697		filter->count = 0;
 698		return 0;
 699	}
 700
 701	alen = ETH_ALEN * uf.count;
 702	addr = kmalloc(alen, GFP_KERNEL);
 703	if (!addr)
 704		return -ENOMEM;
 705
 706	if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 707		err = -EFAULT;
 708		goto done;
 709	}
 710
 711	/* The filter is updated without holding any locks. Which is
 712	 * perfectly safe. We disable it first and in the worst
 713	 * case we'll accept a few undesired packets. */
 714	filter->count = 0;
 715	wmb();
 716
 717	/* Use first set of addresses as an exact filter */
 718	for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 719		memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 720
 721	nexact = n;
 722
 723	/* Remaining multicast addresses are hashed,
 724	 * unicast will leave the filter disabled. */
 725	memset(filter->mask, 0, sizeof(filter->mask));
 726	for (; n < uf.count; n++) {
 727		if (!is_multicast_ether_addr(addr[n].u)) {
 728			err = 0; /* no filter */
 729			goto done;
 730		}
 731		addr_hash_set(filter->mask, addr[n].u);
 732	}
 733
 734	/* For ALLMULTI just set the mask to all ones.
 735	 * This overrides the mask populated above. */
 736	if ((uf.flags & TUN_FLT_ALLMULTI))
 737		memset(filter->mask, ~0, sizeof(filter->mask));
 738
 739	/* Now enable the filter */
 740	wmb();
 741	filter->count = nexact;
 742
 743	/* Return the number of exact filters */
 744	err = nexact;
 745
 746done:
 747	kfree(addr);
 748	return err;
 749}
 750
 751/* Returns: 0 - drop, !=0 - accept */
 752static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 753{
 754	/* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 755	 * at this point. */
 756	struct ethhdr *eh = (struct ethhdr *) skb->data;
 757	int i;
 758
 759	/* Exact match */
 760	for (i = 0; i < filter->count; i++)
 761		if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 762			return 1;
 763
 764	/* Inexact match (multicast only) */
 765	if (is_multicast_ether_addr(eh->h_dest))
 766		return addr_hash_test(filter->mask, eh->h_dest);
 767
 768	return 0;
 769}
 770
 771/*
 772 * Checks whether the packet is accepted or not.
 773 * Returns: 0 - drop, !=0 - accept
 774 */
 775static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 776{
 777	if (!filter->count)
 778		return 1;
 779
 780	return run_filter(filter, skb);
 781}
 782
 783/* Network device part of the driver */
 784
 785static const struct ethtool_ops tun_ethtool_ops;
 786
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 787/* Net device detach from fd. */
 788static void tun_net_uninit(struct net_device *dev)
 789{
 790	tun_detach_all(dev);
 791}
 792
 793/* Net device open. */
 794static int tun_net_open(struct net_device *dev)
 795{
 796	netif_tx_start_all_queues(dev);
 
 797	return 0;
 798}
 799
 800/* Net device close. */
 801static int tun_net_close(struct net_device *dev)
 802{
 803	netif_tx_stop_all_queues(dev);
 804	return 0;
 805}
 806
 807/* Net device start xmit */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 808static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 809{
 810	struct tun_struct *tun = netdev_priv(dev);
 
 811	int txq = skb->queue_mapping;
 
 812	struct tun_file *tfile;
 813	u32 numqueues = 0;
 814
 815	rcu_read_lock();
 816	tfile = rcu_dereference(tun->tfiles[txq]);
 817	numqueues = ACCESS_ONCE(tun->numqueues);
 818
 819	/* Drop packet if interface is not attached */
 820	if (txq >= numqueues)
 
 821		goto drop;
 822
 823	if (numqueues == 1) {
 824		/* Select queue was not called for the skbuff, so we extract the
 825		 * RPS hash and save it into the flow_table here.
 826		 */
 827		__u32 rxhash;
 828
 829		rxhash = skb_get_hash(skb);
 830		if (rxhash) {
 831			struct tun_flow_entry *e;
 832			e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
 833					rxhash);
 834			if (e)
 835				tun_flow_save_rps_rxhash(e, rxhash);
 836		}
 837	}
 838
 839	tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 
 840
 841	BUG_ON(!tfile);
 842
 843	/* Drop if the filter does not like it.
 844	 * This is a noop if the filter is disabled.
 845	 * Filter can be enabled only for the TAP devices. */
 846	if (!check_filter(&tun->txflt, skb))
 
 847		goto drop;
 
 848
 849	if (tfile->socket.sk->sk_filter &&
 850	    sk_filter(tfile->socket.sk, skb))
 
 851		goto drop;
 
 852
 853	/* Limit the number of packets queued by dividing txq length with the
 854	 * number of queues.
 855	 */
 856	if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues
 857			  >= dev->tx_queue_len)
 858		goto drop;
 
 859
 860	if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 
 861		goto drop;
 
 862
 863	if (skb->sk && sk_fullsock(skb->sk)) {
 864		sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags);
 865		sw_tx_timestamp(skb);
 866	}
 867
 
 
 868	/* Orphan the skb - required as we might hang on to it
 869	 * for indefinite time.
 870	 */
 871	skb_orphan(skb);
 872
 873	nf_reset(skb);
 874
 875	/* Enqueue packet */
 876	skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
 
 
 
 
 
 
 877
 878	/* Notify and wake up reader process */
 879	if (tfile->flags & TUN_FASYNC)
 880		kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
 881	tfile->socket.sk->sk_data_ready(tfile->socket.sk);
 882
 883	rcu_read_unlock();
 884	return NETDEV_TX_OK;
 885
 886drop:
 887	dev->stats.tx_dropped++;
 888	skb_tx_error(skb);
 889	kfree_skb(skb);
 890	rcu_read_unlock();
 891	return NET_XMIT_DROP;
 892}
 893
 894static void tun_net_mclist(struct net_device *dev)
 895{
 896	/*
 897	 * This callback is supposed to deal with mc filter in
 898	 * _rx_ path and has nothing to do with the _tx_ path.
 899	 * In rx path we always accept everything userspace gives us.
 900	 */
 901}
 902
 903#define MIN_MTU 68
 904#define MAX_MTU 65535
 905
 906static int
 907tun_net_change_mtu(struct net_device *dev, int new_mtu)
 908{
 909	if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 910		return -EINVAL;
 911	dev->mtu = new_mtu;
 912	return 0;
 913}
 914
 915static netdev_features_t tun_net_fix_features(struct net_device *dev,
 916	netdev_features_t features)
 917{
 918	struct tun_struct *tun = netdev_priv(dev);
 919
 920	return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 921}
 922#ifdef CONFIG_NET_POLL_CONTROLLER
 923static void tun_poll_controller(struct net_device *dev)
 924{
 925	/*
 926	 * Tun only receives frames when:
 927	 * 1) the char device endpoint gets data from user space
 928	 * 2) the tun socket gets a sendmsg call from user space
 929	 * Since both of those are synchronous operations, we are guaranteed
 930	 * never to have pending data when we poll for it
 931	 * so there is nothing to do here but return.
 932	 * We need this though so netpoll recognizes us as an interface that
 933	 * supports polling, which enables bridge devices in virt setups to
 934	 * still use netconsole
 935	 */
 936	return;
 937}
 938#endif
 939
 940static void tun_set_headroom(struct net_device *dev, int new_hr)
 941{
 942	struct tun_struct *tun = netdev_priv(dev);
 943
 944	if (new_hr < NET_SKB_PAD)
 945		new_hr = NET_SKB_PAD;
 946
 947	tun->align = new_hr;
 948}
 949
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 950static const struct net_device_ops tun_netdev_ops = {
 
 951	.ndo_uninit		= tun_net_uninit,
 952	.ndo_open		= tun_net_open,
 953	.ndo_stop		= tun_net_close,
 954	.ndo_start_xmit		= tun_net_xmit,
 955	.ndo_change_mtu		= tun_net_change_mtu,
 956	.ndo_fix_features	= tun_net_fix_features,
 957	.ndo_select_queue	= tun_select_queue,
 958#ifdef CONFIG_NET_POLL_CONTROLLER
 959	.ndo_poll_controller	= tun_poll_controller,
 960#endif
 961	.ndo_set_rx_headroom	= tun_set_headroom,
 
 
 962};
 963
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 964static const struct net_device_ops tap_netdev_ops = {
 
 965	.ndo_uninit		= tun_net_uninit,
 966	.ndo_open		= tun_net_open,
 967	.ndo_stop		= tun_net_close,
 968	.ndo_start_xmit		= tun_net_xmit,
 969	.ndo_change_mtu		= tun_net_change_mtu,
 970	.ndo_fix_features	= tun_net_fix_features,
 971	.ndo_set_rx_mode	= tun_net_mclist,
 972	.ndo_set_mac_address	= eth_mac_addr,
 973	.ndo_validate_addr	= eth_validate_addr,
 974	.ndo_select_queue	= tun_select_queue,
 975#ifdef CONFIG_NET_POLL_CONTROLLER
 976	.ndo_poll_controller	= tun_poll_controller,
 977#endif
 978	.ndo_features_check	= passthru_features_check,
 979	.ndo_set_rx_headroom	= tun_set_headroom,
 
 
 
 
 980};
 981
 982static void tun_flow_init(struct tun_struct *tun)
 983{
 984	int i;
 985
 986	for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
 987		INIT_HLIST_HEAD(&tun->flows[i]);
 988
 989	tun->ageing_time = TUN_FLOW_EXPIRE;
 990	setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
 991	mod_timer(&tun->flow_gc_timer,
 992		  round_jiffies_up(jiffies + tun->ageing_time));
 993}
 994
 995static void tun_flow_uninit(struct tun_struct *tun)
 996{
 997	del_timer_sync(&tun->flow_gc_timer);
 998	tun_flow_flush(tun);
 999}
1000
 
 
 
1001/* Initialize net device. */
1002static void tun_net_init(struct net_device *dev)
1003{
1004	struct tun_struct *tun = netdev_priv(dev);
1005
1006	switch (tun->flags & TUN_TYPE_MASK) {
1007	case IFF_TUN:
1008		dev->netdev_ops = &tun_netdev_ops;
 
1009
1010		/* Point-to-Point TUN Device */
1011		dev->hard_header_len = 0;
1012		dev->addr_len = 0;
1013		dev->mtu = 1500;
1014
1015		/* Zero header length */
1016		dev->type = ARPHRD_NONE;
1017		dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1018		break;
1019
1020	case IFF_TAP:
1021		dev->netdev_ops = &tap_netdev_ops;
1022		/* Ethernet TAP Device */
1023		ether_setup(dev);
1024		dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1025		dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1026
1027		eth_hw_addr_random(dev);
1028
1029		break;
1030	}
 
 
 
 
 
 
 
 
 
 
1031}
1032
1033/* Character device part */
1034
1035/* Poll */
1036static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1037{
1038	struct tun_file *tfile = file->private_data;
1039	struct tun_struct *tun = __tun_get(tfile);
1040	struct sock *sk;
1041	unsigned int mask = 0;
1042
1043	if (!tun)
1044		return POLLERR;
1045
1046	sk = tfile->socket.sk;
1047
1048	tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1049
1050	poll_wait(file, sk_sleep(sk), wait);
1051
1052	if (!skb_queue_empty(&sk->sk_receive_queue))
1053		mask |= POLLIN | POLLRDNORM;
1054
1055	if (sock_writeable(sk) ||
 
 
 
 
 
1056	    (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1057	     sock_writeable(sk)))
1058		mask |= POLLOUT | POLLWRNORM;
1059
1060	if (tun->dev->reg_state != NETREG_REGISTERED)
1061		mask = POLLERR;
1062
1063	tun_put(tun);
1064	return mask;
1065}
1066
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1067/* prepad is the amount to reserve at front.  len is length after that.
1068 * linear is a hint as to how much to copy (usually headers). */
1069static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1070				     size_t prepad, size_t len,
1071				     size_t linear, int noblock)
1072{
1073	struct sock *sk = tfile->socket.sk;
1074	struct sk_buff *skb;
1075	int err;
1076
1077	/* Under a page?  Don't bother with paged skb. */
1078	if (prepad + len < PAGE_SIZE || !linear)
1079		linear = len;
1080
1081	skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1082				   &err, 0);
1083	if (!skb)
1084		return ERR_PTR(err);
1085
1086	skb_reserve(skb, prepad);
1087	skb_put(skb, linear);
1088	skb->data_len = len - linear;
1089	skb->len += len - linear;
1090
1091	return skb;
1092}
1093
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1094/* Get packet from user space buffer */
1095static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1096			    void *msg_control, struct iov_iter *from,
1097			    int noblock)
1098{
1099	struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1100	struct sk_buff *skb;
1101	size_t total_len = iov_iter_count(from);
1102	size_t len = total_len, align = tun->align, linear;
1103	struct virtio_net_hdr gso = { 0 };
1104	int good_linear;
1105	int copylen;
1106	bool zerocopy = false;
1107	int err;
1108	u32 rxhash;
1109	ssize_t n;
1110
1111	if (!(tun->dev->flags & IFF_UP))
1112		return -EIO;
1113
1114	if (!(tun->flags & IFF_NO_PI)) {
1115		if (len < sizeof(pi))
1116			return -EINVAL;
1117		len -= sizeof(pi);
1118
1119		n = copy_from_iter(&pi, sizeof(pi), from);
1120		if (n != sizeof(pi))
1121			return -EFAULT;
1122	}
1123
1124	if (tun->flags & IFF_VNET_HDR) {
1125		if (len < tun->vnet_hdr_sz)
 
 
1126			return -EINVAL;
1127		len -= tun->vnet_hdr_sz;
1128
1129		n = copy_from_iter(&gso, sizeof(gso), from);
1130		if (n != sizeof(gso))
1131			return -EFAULT;
1132
1133		if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1134		    tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1135			gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1136
1137		if (tun16_to_cpu(tun, gso.hdr_len) > len)
1138			return -EINVAL;
1139		iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso));
1140	}
1141
1142	if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1143		align += NET_IP_ALIGN;
1144		if (unlikely(len < ETH_HLEN ||
1145			     (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1146			return -EINVAL;
1147	}
1148
1149	good_linear = SKB_MAX_HEAD(align);
1150
1151	if (msg_control) {
1152		struct iov_iter i = *from;
1153
1154		/* There are 256 bytes to be copied in skb, so there is
1155		 * enough room for skb expand head in case it is used.
1156		 * The rest of the buffer is mapped from userspace.
1157		 */
1158		copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1159		if (copylen > good_linear)
1160			copylen = good_linear;
1161		linear = copylen;
1162		iov_iter_advance(&i, copylen);
1163		if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1164			zerocopy = true;
1165	}
1166
1167	if (!zerocopy) {
1168		copylen = len;
1169		if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1170			linear = good_linear;
1171		else
1172			linear = tun16_to_cpu(tun, gso.hdr_len);
1173	}
1174
1175	skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1176	if (IS_ERR(skb)) {
1177		if (PTR_ERR(skb) != -EAGAIN)
1178			tun->dev->stats.rx_dropped++;
1179		return PTR_ERR(skb);
1180	}
 
 
 
 
 
1181
1182	if (zerocopy)
1183		err = zerocopy_sg_from_iter(skb, from);
1184	else {
1185		err = skb_copy_datagram_from_iter(skb, 0, from, len);
1186		if (!err && msg_control) {
1187			struct ubuf_info *uarg = msg_control;
1188			uarg->callback(uarg, false);
 
 
 
 
1189		}
1190	}
1191
1192	if (err) {
1193		tun->dev->stats.rx_dropped++;
1194		kfree_skb(skb);
1195		return -EFAULT;
1196	}
1197
1198	if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1199		if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start),
1200					  tun16_to_cpu(tun, gso.csum_offset))) {
1201			tun->dev->stats.rx_frame_errors++;
1202			kfree_skb(skb);
1203			return -EINVAL;
 
 
 
1204		}
1205	}
1206
 
 
 
 
 
 
1207	switch (tun->flags & TUN_TYPE_MASK) {
1208	case IFF_TUN:
1209		if (tun->flags & IFF_NO_PI) {
1210			switch (skb->data[0] & 0xf0) {
1211			case 0x40:
 
 
1212				pi.proto = htons(ETH_P_IP);
1213				break;
1214			case 0x60:
1215				pi.proto = htons(ETH_P_IPV6);
1216				break;
1217			default:
1218				tun->dev->stats.rx_dropped++;
1219				kfree_skb(skb);
1220				return -EINVAL;
1221			}
1222		}
1223
1224		skb_reset_mac_header(skb);
1225		skb->protocol = pi.proto;
1226		skb->dev = tun->dev;
1227		break;
1228	case IFF_TAP:
 
 
 
 
 
1229		skb->protocol = eth_type_trans(skb, tun->dev);
1230		break;
1231	}
1232
1233	if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1234		pr_debug("GSO!\n");
1235		switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1236		case VIRTIO_NET_HDR_GSO_TCPV4:
1237			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1238			break;
1239		case VIRTIO_NET_HDR_GSO_TCPV6:
1240			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1241			break;
1242		case VIRTIO_NET_HDR_GSO_UDP:
1243			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1244			break;
1245		default:
1246			tun->dev->stats.rx_frame_errors++;
1247			kfree_skb(skb);
1248			return -EINVAL;
1249		}
1250
1251		if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1252			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 
1253
1254		skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size);
1255		if (skb_shinfo(skb)->gso_size == 0) {
1256			tun->dev->stats.rx_frame_errors++;
1257			kfree_skb(skb);
1258			return -EINVAL;
1259		}
1260
1261		/* Header must be checked, and gso_segs computed. */
1262		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1263		skb_shinfo(skb)->gso_segs = 0;
 
 
 
 
 
 
 
 
 
 
1264	}
1265
1266	/* copy skb_ubuf_info for callback when skb has no error */
1267	if (zerocopy) {
1268		skb_shinfo(skb)->destructor_arg = msg_control;
1269		skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1270		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
 
 
 
 
 
 
 
 
 
1271	}
1272
1273	skb_reset_network_header(skb);
1274	skb_probe_transport_header(skb, 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1275
1276	rxhash = skb_get_hash(skb);
1277	netif_rx_ni(skb);
 
1278
1279	tun->dev->stats.rx_packets++;
1280	tun->dev->stats.rx_bytes += len;
1281
1282	tun_flow_update(tun, rxhash, tfile);
1283	return total_len;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1284}
1285
1286static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1287{
1288	struct file *file = iocb->ki_filp;
1289	struct tun_struct *tun = tun_get(file);
1290	struct tun_file *tfile = file->private_data;
 
1291	ssize_t result;
 
1292
1293	if (!tun)
1294		return -EBADFD;
1295
1296	result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);
 
 
 
1297
1298	tun_put(tun);
1299	return result;
1300}
1301
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1302/* Put packet to the user space buffer */
1303static ssize_t tun_put_user(struct tun_struct *tun,
1304			    struct tun_file *tfile,
1305			    struct sk_buff *skb,
1306			    struct iov_iter *iter)
1307{
1308	struct tun_pi pi = { 0, skb->protocol };
1309	ssize_t total;
1310	int vlan_offset = 0;
1311	int vlan_hlen = 0;
1312	int vnet_hdr_sz = 0;
1313
1314	if (skb_vlan_tag_present(skb))
1315		vlan_hlen = VLAN_HLEN;
1316
1317	if (tun->flags & IFF_VNET_HDR)
1318		vnet_hdr_sz = tun->vnet_hdr_sz;
1319
1320	total = skb->len + vlan_hlen + vnet_hdr_sz;
1321
1322	if (!(tun->flags & IFF_NO_PI)) {
1323		if (iov_iter_count(iter) < sizeof(pi))
1324			return -EINVAL;
1325
1326		total += sizeof(pi);
1327		if (iov_iter_count(iter) < total) {
1328			/* Packet will be striped */
1329			pi.flags |= TUN_PKT_STRIP;
1330		}
1331
1332		if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1333			return -EFAULT;
1334	}
1335
1336	if (vnet_hdr_sz) {
1337		struct virtio_net_hdr gso = { 0 }; /* no info leak */
 
1338		if (iov_iter_count(iter) < vnet_hdr_sz)
1339			return -EINVAL;
1340
1341		if (skb_is_gso(skb)) {
 
 
1342			struct skb_shared_info *sinfo = skb_shinfo(skb);
1343
1344			/* This is a hint as to how much should be linear. */
1345			gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb));
1346			gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size);
1347			if (sinfo->gso_type & SKB_GSO_TCPV4)
1348				gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1349			else if (sinfo->gso_type & SKB_GSO_TCPV6)
1350				gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1351			else if (sinfo->gso_type & SKB_GSO_UDP)
1352				gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1353			else {
1354				pr_err("unexpected GSO type: "
1355				       "0x%x, gso_size %d, hdr_len %d\n",
1356				       sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1357				       tun16_to_cpu(tun, gso.hdr_len));
1358				print_hex_dump(KERN_ERR, "tun: ",
1359					       DUMP_PREFIX_NONE,
1360					       16, 1, skb->head,
1361					       min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1362				WARN_ON_ONCE(1);
1363				return -EINVAL;
1364			}
1365			if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1366				gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1367		} else
1368			gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1369
1370		if (skb->ip_summed == CHECKSUM_PARTIAL) {
1371			gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1372			gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) +
1373						      vlan_hlen);
1374			gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset);
1375		} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1376			gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1377		} /* else everything is zero */
1378
1379		if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1380			return -EFAULT;
1381
1382		iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1383	}
1384
1385	if (vlan_hlen) {
1386		int ret;
1387		struct {
1388			__be16 h_vlan_proto;
1389			__be16 h_vlan_TCI;
1390		} veth;
1391
1392		veth.h_vlan_proto = skb->vlan_proto;
1393		veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1394
1395		vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1396
1397		ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1398		if (ret || !iov_iter_count(iter))
1399			goto done;
1400
1401		ret = copy_to_iter(&veth, sizeof(veth), iter);
1402		if (ret != sizeof(veth) || !iov_iter_count(iter))
1403			goto done;
1404	}
1405
1406	skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1407
1408done:
1409	tun->dev->stats.tx_packets++;
1410	tun->dev->stats.tx_bytes += skb->len + vlan_hlen;
 
 
1411
1412	return total;
1413}
1414
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1415static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1416			   struct iov_iter *to,
1417			   int noblock)
1418{
1419	struct sk_buff *skb;
1420	ssize_t ret;
1421	int peeked, err, off = 0;
1422
1423	tun_debug(KERN_INFO, tun, "tun_do_read\n");
1424
1425	if (!iov_iter_count(to))
 
1426		return 0;
 
1427
1428	if (tun->dev->reg_state != NETREG_REGISTERED)
1429		return -EIO;
 
 
 
 
1430
1431	/* Read frames from queue */
1432	skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0,
1433				  &peeked, &off, &err);
1434	if (!skb)
1435		return err;
1436
1437	ret = tun_put_user(tun, tfile, skb, to);
1438	if (unlikely(ret < 0))
1439		kfree_skb(skb);
1440	else
1441		consume_skb(skb);
 
 
 
 
 
 
1442
1443	return ret;
1444}
1445
1446static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1447{
1448	struct file *file = iocb->ki_filp;
1449	struct tun_file *tfile = file->private_data;
1450	struct tun_struct *tun = __tun_get(tfile);
1451	ssize_t len = iov_iter_count(to), ret;
 
1452
1453	if (!tun)
1454		return -EBADFD;
1455	ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
 
 
 
 
1456	ret = min_t(ssize_t, ret, len);
1457	if (ret > 0)
1458		iocb->ki_pos = ret;
1459	tun_put(tun);
1460	return ret;
1461}
1462
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1463static void tun_free_netdev(struct net_device *dev)
1464{
1465	struct tun_struct *tun = netdev_priv(dev);
1466
1467	BUG_ON(!(list_empty(&tun->disabled)));
 
 
1468	tun_flow_uninit(tun);
1469	security_tun_dev_free_security(tun->security);
1470	free_netdev(dev);
 
1471}
1472
1473static void tun_setup(struct net_device *dev)
1474{
1475	struct tun_struct *tun = netdev_priv(dev);
1476
1477	tun->owner = INVALID_UID;
1478	tun->group = INVALID_GID;
 
1479
1480	dev->ethtool_ops = &tun_ethtool_ops;
1481	dev->destructor = tun_free_netdev;
 
1482	/* We prefer our own queue length */
1483	dev->tx_queue_len = TUN_READQ_SIZE;
1484}
1485
1486/* Trivial set of netlink ops to allow deleting tun or tap
1487 * device with netlink.
1488 */
1489static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
 
1490{
1491	return -EINVAL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1492}
1493
1494static struct rtnl_link_ops tun_link_ops __read_mostly = {
1495	.kind		= DRV_NAME,
1496	.priv_size	= sizeof(struct tun_struct),
1497	.setup		= tun_setup,
1498	.validate	= tun_validate,
 
 
1499};
1500
1501static void tun_sock_write_space(struct sock *sk)
1502{
1503	struct tun_file *tfile;
1504	wait_queue_head_t *wqueue;
1505
1506	if (!sock_writeable(sk))
1507		return;
1508
1509	if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
1510		return;
1511
1512	wqueue = sk_sleep(sk);
1513	if (wqueue && waitqueue_active(wqueue))
1514		wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1515						POLLWRNORM | POLLWRBAND);
1516
1517	tfile = container_of(sk, struct tun_file, sk);
1518	kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1519}
1520
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1521static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1522{
1523	int ret;
1524	struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1525	struct tun_struct *tun = __tun_get(tfile);
 
 
1526
1527	if (!tun)
1528		return -EBADFD;
1529
1530	ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1531			   m->msg_flags & MSG_DONTWAIT);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1532	tun_put(tun);
1533	return ret;
1534}
1535
1536static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1537		       int flags)
1538{
1539	struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1540	struct tun_struct *tun = __tun_get(tfile);
 
1541	int ret;
1542
1543	if (!tun)
1544		return -EBADFD;
 
 
1545
1546	if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1547		ret = -EINVAL;
1548		goto out;
1549	}
1550	if (flags & MSG_ERRQUEUE) {
1551		ret = sock_recv_errqueue(sock->sk, m, total_len,
1552					 SOL_PACKET, TUN_TX_TIMESTAMP);
1553		goto out;
1554	}
1555	ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1556	if (ret > (ssize_t)total_len) {
1557		m->msg_flags |= MSG_TRUNC;
1558		ret = flags & MSG_TRUNC ? ret : total_len;
1559	}
1560out:
1561	tun_put(tun);
1562	return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1563}
1564
1565/* Ops structure to mimic raw sockets with tun */
1566static const struct proto_ops tun_socket_ops = {
 
1567	.sendmsg = tun_sendmsg,
1568	.recvmsg = tun_recvmsg,
1569};
1570
1571static struct proto tun_proto = {
1572	.name		= "tun",
1573	.owner		= THIS_MODULE,
1574	.obj_size	= sizeof(struct tun_file),
1575};
1576
1577static int tun_flags(struct tun_struct *tun)
1578{
1579	return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1580}
1581
1582static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1583			      char *buf)
1584{
1585	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1586	return sprintf(buf, "0x%x\n", tun_flags(tun));
1587}
1588
1589static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1590			      char *buf)
1591{
1592	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1593	return uid_valid(tun->owner)?
1594		sprintf(buf, "%u\n",
1595			from_kuid_munged(current_user_ns(), tun->owner)):
1596		sprintf(buf, "-1\n");
1597}
1598
1599static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1600			      char *buf)
1601{
1602	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1603	return gid_valid(tun->group) ?
1604		sprintf(buf, "%u\n",
1605			from_kgid_munged(current_user_ns(), tun->group)):
1606		sprintf(buf, "-1\n");
1607}
1608
1609static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1610static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1611static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1612
1613static struct attribute *tun_dev_attrs[] = {
1614	&dev_attr_tun_flags.attr,
1615	&dev_attr_owner.attr,
1616	&dev_attr_group.attr,
1617	NULL
1618};
1619
1620static const struct attribute_group tun_attr_group = {
1621	.attrs = tun_dev_attrs
1622};
1623
1624static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1625{
1626	struct tun_struct *tun;
1627	struct tun_file *tfile = file->private_data;
1628	struct net_device *dev;
1629	int err;
1630
1631	if (tfile->detached)
1632		return -EINVAL;
1633
 
 
 
 
 
 
 
 
 
1634	dev = __dev_get_by_name(net, ifr->ifr_name);
1635	if (dev) {
1636		if (ifr->ifr_flags & IFF_TUN_EXCL)
1637			return -EBUSY;
1638		if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1639			tun = netdev_priv(dev);
1640		else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1641			tun = netdev_priv(dev);
1642		else
1643			return -EINVAL;
1644
1645		if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1646		    !!(tun->flags & IFF_MULTI_QUEUE))
1647			return -EINVAL;
1648
1649		if (tun_not_capable(tun))
1650			return -EPERM;
1651		err = security_tun_dev_open(tun->security);
1652		if (err < 0)
1653			return err;
1654
1655		err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
 
 
1656		if (err < 0)
1657			return err;
1658
1659		if (tun->flags & IFF_MULTI_QUEUE &&
1660		    (tun->numqueues + tun->numdisabled > 1)) {
1661			/* One or more queue has already been attached, no need
1662			 * to initialize the device again.
1663			 */
 
1664			return 0;
1665		}
1666	}
1667	else {
 
 
 
 
1668		char *name;
1669		unsigned long flags = 0;
1670		int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1671			     MAX_TAP_QUEUES : 1;
1672
1673		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1674			return -EPERM;
1675		err = security_tun_dev_create();
1676		if (err < 0)
1677			return err;
1678
1679		/* Set dev type */
1680		if (ifr->ifr_flags & IFF_TUN) {
1681			/* TUN device */
1682			flags |= IFF_TUN;
1683			name = "tun%d";
1684		} else if (ifr->ifr_flags & IFF_TAP) {
1685			/* TAP device */
1686			flags |= IFF_TAP;
1687			name = "tap%d";
1688		} else
1689			return -EINVAL;
1690
1691		if (*ifr->ifr_name)
1692			name = ifr->ifr_name;
1693
1694		dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1695				       NET_NAME_UNKNOWN, tun_setup, queues,
1696				       queues);
1697
1698		if (!dev)
1699			return -ENOMEM;
1700
1701		dev_net_set(dev, net);
1702		dev->rtnl_link_ops = &tun_link_ops;
1703		dev->ifindex = tfile->ifindex;
1704		dev->sysfs_groups[0] = &tun_attr_group;
1705
1706		tun = netdev_priv(dev);
1707		tun->dev = dev;
1708		tun->flags = flags;
1709		tun->txflt.count = 0;
1710		tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1711
1712		tun->align = NET_SKB_PAD;
1713		tun->filter_attached = false;
1714		tun->sndbuf = tfile->socket.sk->sk_sndbuf;
 
 
1715
1716		spin_lock_init(&tun->lock);
 
1717
1718		err = security_tun_dev_alloc_security(&tun->security);
1719		if (err < 0)
1720			goto err_free_dev;
1721
1722		tun_net_init(dev);
1723		tun_flow_init(tun);
1724
1725		dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1726				   TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1727				   NETIF_F_HW_VLAN_STAG_TX;
1728		dev->features = dev->hw_features;
1729		dev->vlan_features = dev->features &
1730				     ~(NETIF_F_HW_VLAN_CTAG_TX |
1731				       NETIF_F_HW_VLAN_STAG_TX);
1732
1733		INIT_LIST_HEAD(&tun->disabled);
1734		err = tun_attach(tun, file, false);
1735		if (err < 0)
1736			goto err_free_flow;
1737
1738		err = register_netdevice(tun->dev);
1739		if (err < 0)
1740			goto err_detach;
 
 
 
 
 
 
1741	}
1742
1743	netif_carrier_on(tun->dev);
1744
1745	tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1746
1747	tun->flags = (tun->flags & ~TUN_FEATURES) |
1748		(ifr->ifr_flags & TUN_FEATURES);
1749
1750	/* Make sure persistent devices do not get stuck in
1751	 * xoff state.
1752	 */
1753	if (netif_running(tun->dev))
1754		netif_tx_wake_all_queues(tun->dev);
1755
1756	strcpy(ifr->ifr_name, tun->dev->name);
1757	return 0;
1758
1759err_detach:
1760	tun_detach_all(dev);
1761err_free_flow:
1762	tun_flow_uninit(tun);
1763	security_tun_dev_free_security(tun->security);
1764err_free_dev:
1765	free_netdev(dev);
1766	return err;
1767}
1768
1769static void tun_get_iff(struct net *net, struct tun_struct *tun,
1770		       struct ifreq *ifr)
1771{
1772	tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1773
1774	strcpy(ifr->ifr_name, tun->dev->name);
1775
1776	ifr->ifr_flags = tun_flags(tun);
1777
1778}
1779
1780/* This is like a cut-down ethtool ops, except done via tun fd so no
1781 * privs required. */
1782static int set_offload(struct tun_struct *tun, unsigned long arg)
1783{
1784	netdev_features_t features = 0;
1785
1786	if (arg & TUN_F_CSUM) {
1787		features |= NETIF_F_HW_CSUM;
1788		arg &= ~TUN_F_CSUM;
1789
1790		if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1791			if (arg & TUN_F_TSO_ECN) {
1792				features |= NETIF_F_TSO_ECN;
1793				arg &= ~TUN_F_TSO_ECN;
1794			}
1795			if (arg & TUN_F_TSO4)
1796				features |= NETIF_F_TSO;
1797			if (arg & TUN_F_TSO6)
1798				features |= NETIF_F_TSO6;
1799			arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1800		}
1801
1802		if (arg & TUN_F_UFO) {
1803			features |= NETIF_F_UFO;
1804			arg &= ~TUN_F_UFO;
 
 
 
1805		}
1806	}
1807
1808	/* This gives the user a way to test for new features in future by
1809	 * trying to set them. */
1810	if (arg)
1811		return -EINVAL;
1812
1813	tun->set_features = features;
 
 
1814	netdev_update_features(tun->dev);
1815
1816	return 0;
1817}
1818
1819static void tun_detach_filter(struct tun_struct *tun, int n)
1820{
1821	int i;
1822	struct tun_file *tfile;
1823
1824	for (i = 0; i < n; i++) {
1825		tfile = rtnl_dereference(tun->tfiles[i]);
1826		__sk_detach_filter(tfile->socket.sk, lockdep_rtnl_is_held());
 
 
1827	}
1828
1829	tun->filter_attached = false;
1830}
1831
1832static int tun_attach_filter(struct tun_struct *tun)
1833{
1834	int i, ret = 0;
1835	struct tun_file *tfile;
1836
1837	for (i = 0; i < tun->numqueues; i++) {
1838		tfile = rtnl_dereference(tun->tfiles[i]);
1839		ret = __sk_attach_filter(&tun->fprog, tfile->socket.sk,
1840					 lockdep_rtnl_is_held());
 
1841		if (ret) {
1842			tun_detach_filter(tun, i);
1843			return ret;
1844		}
1845	}
1846
1847	tun->filter_attached = true;
1848	return ret;
1849}
1850
1851static void tun_set_sndbuf(struct tun_struct *tun)
1852{
1853	struct tun_file *tfile;
1854	int i;
1855
1856	for (i = 0; i < tun->numqueues; i++) {
1857		tfile = rtnl_dereference(tun->tfiles[i]);
1858		tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1859	}
1860}
1861
1862static int tun_set_queue(struct file *file, struct ifreq *ifr)
1863{
1864	struct tun_file *tfile = file->private_data;
1865	struct tun_struct *tun;
1866	int ret = 0;
1867
1868	rtnl_lock();
1869
1870	if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1871		tun = tfile->detached;
1872		if (!tun) {
1873			ret = -EINVAL;
1874			goto unlock;
1875		}
1876		ret = security_tun_dev_attach_queue(tun->security);
1877		if (ret < 0)
1878			goto unlock;
1879		ret = tun_attach(tun, file, false);
 
1880	} else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1881		tun = rtnl_dereference(tfile->tun);
1882		if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1883			ret = -EINVAL;
1884		else
1885			__tun_detach(tfile, false);
1886	} else
1887		ret = -EINVAL;
1888
 
 
 
1889unlock:
1890	rtnl_unlock();
1891	return ret;
1892}
1893
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1894static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1895			    unsigned long arg, int ifreq_len)
1896{
1897	struct tun_file *tfile = file->private_data;
 
1898	struct tun_struct *tun;
1899	void __user* argp = (void __user*)arg;
 
1900	struct ifreq ifr;
1901	kuid_t owner;
1902	kgid_t group;
1903	int sndbuf;
1904	int vnet_hdr_sz;
1905	unsigned int ifindex;
1906	int le;
1907	int ret;
 
1908
1909	if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
 
1910		if (copy_from_user(&ifr, argp, ifreq_len))
1911			return -EFAULT;
1912	} else {
1913		memset(&ifr, 0, sizeof(ifr));
1914	}
1915	if (cmd == TUNGETFEATURES) {
1916		/* Currently this just means: "what IFF flags are valid?".
1917		 * This is needed because we never checked for invalid flags on
1918		 * TUNSETIFF.
1919		 */
1920		return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
1921				(unsigned int __user*)argp);
1922	} else if (cmd == TUNSETQUEUE)
1923		return tun_set_queue(file, &ifr);
 
 
 
 
 
1924
1925	ret = 0;
1926	rtnl_lock();
1927
1928	tun = __tun_get(tfile);
1929	if (cmd == TUNSETIFF && !tun) {
 
 
 
 
1930		ifr.ifr_name[IFNAMSIZ-1] = '\0';
1931
1932		ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
1933
1934		if (ret)
1935			goto unlock;
1936
1937		if (copy_to_user(argp, &ifr, ifreq_len))
1938			ret = -EFAULT;
1939		goto unlock;
1940	}
1941	if (cmd == TUNSETIFINDEX) {
1942		ret = -EPERM;
1943		if (tun)
1944			goto unlock;
1945
1946		ret = -EFAULT;
1947		if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
1948			goto unlock;
1949
1950		ret = 0;
1951		tfile->ifindex = ifindex;
1952		goto unlock;
1953	}
1954
1955	ret = -EBADFD;
1956	if (!tun)
1957		goto unlock;
1958
1959	tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1960
 
1961	ret = 0;
1962	switch (cmd) {
1963	case TUNGETIFF:
1964		tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1965
1966		if (tfile->detached)
1967			ifr.ifr_flags |= IFF_DETACH_QUEUE;
1968		if (!tfile->socket.sk->sk_filter)
1969			ifr.ifr_flags |= IFF_NOFILTER;
1970
1971		if (copy_to_user(argp, &ifr, ifreq_len))
1972			ret = -EFAULT;
1973		break;
1974
1975	case TUNSETNOCSUM:
1976		/* Disable/Enable checksum */
1977
1978		/* [unimplemented] */
1979		tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1980			  arg ? "disabled" : "enabled");
1981		break;
1982
1983	case TUNSETPERSIST:
1984		/* Disable/Enable persist mode. Keep an extra reference to the
1985		 * module to prevent the module being unprobed.
1986		 */
1987		if (arg && !(tun->flags & IFF_PERSIST)) {
1988			tun->flags |= IFF_PERSIST;
1989			__module_get(THIS_MODULE);
 
1990		}
1991		if (!arg && (tun->flags & IFF_PERSIST)) {
1992			tun->flags &= ~IFF_PERSIST;
1993			module_put(THIS_MODULE);
 
1994		}
1995
1996		tun_debug(KERN_INFO, tun, "persist %s\n",
1997			  arg ? "enabled" : "disabled");
1998		break;
1999
2000	case TUNSETOWNER:
2001		/* Set owner of the device */
2002		owner = make_kuid(current_user_ns(), arg);
2003		if (!uid_valid(owner)) {
2004			ret = -EINVAL;
2005			break;
2006		}
2007		tun->owner = owner;
2008		tun_debug(KERN_INFO, tun, "owner set to %u\n",
2009			  from_kuid(&init_user_ns, tun->owner));
 
2010		break;
2011
2012	case TUNSETGROUP:
2013		/* Set group of the device */
2014		group = make_kgid(current_user_ns(), arg);
2015		if (!gid_valid(group)) {
2016			ret = -EINVAL;
2017			break;
2018		}
2019		tun->group = group;
2020		tun_debug(KERN_INFO, tun, "group set to %u\n",
2021			  from_kgid(&init_user_ns, tun->group));
 
2022		break;
2023
2024	case TUNSETLINK:
2025		/* Only allow setting the type when the interface is down */
2026		if (tun->dev->flags & IFF_UP) {
2027			tun_debug(KERN_INFO, tun,
2028				  "Linktype set failed because interface is up\n");
2029			ret = -EBUSY;
2030		} else {
 
 
 
 
 
 
 
 
2031			tun->dev->type = (int) arg;
2032			tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2033				  tun->dev->type);
2034			ret = 0;
 
 
2035		}
2036		break;
2037
2038#ifdef TUN_DEBUG
2039	case TUNSETDEBUG:
2040		tun->debug = arg;
2041		break;
2042#endif
2043	case TUNSETOFFLOAD:
2044		ret = set_offload(tun, arg);
2045		break;
2046
2047	case TUNSETTXFILTER:
2048		/* Can be set only for TAPs */
2049		ret = -EINVAL;
2050		if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2051			break;
2052		ret = update_filter(&tun->txflt, (void __user *)arg);
2053		break;
2054
2055	case SIOCGIFHWADDR:
2056		/* Get hw address */
2057		memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2058		ifr.ifr_hwaddr.sa_family = tun->dev->type;
2059		if (copy_to_user(argp, &ifr, ifreq_len))
2060			ret = -EFAULT;
2061		break;
2062
2063	case SIOCSIFHWADDR:
2064		/* Set hw address */
2065		tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2066			  ifr.ifr_hwaddr.sa_data);
2067
2068		ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2069		break;
2070
2071	case TUNGETSNDBUF:
2072		sndbuf = tfile->socket.sk->sk_sndbuf;
2073		if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2074			ret = -EFAULT;
2075		break;
2076
2077	case TUNSETSNDBUF:
2078		if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2079			ret = -EFAULT;
2080			break;
2081		}
 
 
 
 
2082
2083		tun->sndbuf = sndbuf;
2084		tun_set_sndbuf(tun);
2085		break;
2086
2087	case TUNGETVNETHDRSZ:
2088		vnet_hdr_sz = tun->vnet_hdr_sz;
2089		if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2090			ret = -EFAULT;
2091		break;
2092
2093	case TUNSETVNETHDRSZ:
2094		if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2095			ret = -EFAULT;
2096			break;
2097		}
2098		if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2099			ret = -EINVAL;
2100			break;
2101		}
2102
2103		tun->vnet_hdr_sz = vnet_hdr_sz;
2104		break;
2105
2106	case TUNGETVNETLE:
2107		le = !!(tun->flags & TUN_VNET_LE);
2108		if (put_user(le, (int __user *)argp))
2109			ret = -EFAULT;
2110		break;
2111
2112	case TUNSETVNETLE:
2113		if (get_user(le, (int __user *)argp)) {
2114			ret = -EFAULT;
2115			break;
2116		}
2117		if (le)
2118			tun->flags |= TUN_VNET_LE;
2119		else
2120			tun->flags &= ~TUN_VNET_LE;
2121		break;
2122
2123	case TUNGETVNETBE:
2124		ret = tun_get_vnet_be(tun, argp);
2125		break;
2126
2127	case TUNSETVNETBE:
2128		ret = tun_set_vnet_be(tun, argp);
2129		break;
2130
2131	case TUNATTACHFILTER:
2132		/* Can be set only for TAPs */
2133		ret = -EINVAL;
2134		if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2135			break;
2136		ret = -EFAULT;
2137		if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2138			break;
2139
2140		ret = tun_attach_filter(tun);
2141		break;
2142
2143	case TUNDETACHFILTER:
2144		/* Can be set only for TAPs */
2145		ret = -EINVAL;
2146		if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2147			break;
2148		ret = 0;
2149		tun_detach_filter(tun, tun->numqueues);
2150		break;
2151
2152	case TUNGETFILTER:
2153		ret = -EINVAL;
2154		if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2155			break;
2156		ret = -EFAULT;
2157		if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2158			break;
2159		ret = 0;
2160		break;
2161
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2162	default:
2163		ret = -EINVAL;
2164		break;
2165	}
2166
 
 
 
2167unlock:
2168	rtnl_unlock();
2169	if (tun)
2170		tun_put(tun);
2171	return ret;
2172}
2173
2174static long tun_chr_ioctl(struct file *file,
2175			  unsigned int cmd, unsigned long arg)
2176{
2177	return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2178}
2179
2180#ifdef CONFIG_COMPAT
2181static long tun_chr_compat_ioctl(struct file *file,
2182			 unsigned int cmd, unsigned long arg)
2183{
2184	switch (cmd) {
2185	case TUNSETIFF:
2186	case TUNGETIFF:
2187	case TUNSETTXFILTER:
2188	case TUNGETSNDBUF:
2189	case TUNSETSNDBUF:
2190	case SIOCGIFHWADDR:
2191	case SIOCSIFHWADDR:
2192		arg = (unsigned long)compat_ptr(arg);
2193		break;
2194	default:
2195		arg = (compat_ulong_t)arg;
2196		break;
2197	}
2198
2199	/*
2200	 * compat_ifreq is shorter than ifreq, so we must not access beyond
2201	 * the end of that structure. All fields that are used in this
2202	 * driver are compatible though, we don't need to convert the
2203	 * contents.
2204	 */
2205	return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2206}
2207#endif /* CONFIG_COMPAT */
2208
2209static int tun_chr_fasync(int fd, struct file *file, int on)
2210{
2211	struct tun_file *tfile = file->private_data;
2212	int ret;
2213
2214	if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2215		goto out;
2216
2217	if (on) {
2218		__f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2219		tfile->flags |= TUN_FASYNC;
2220	} else
2221		tfile->flags &= ~TUN_FASYNC;
2222	ret = 0;
2223out:
2224	return ret;
2225}
2226
2227static int tun_chr_open(struct inode *inode, struct file * file)
2228{
2229	struct net *net = current->nsproxy->net_ns;
2230	struct tun_file *tfile;
2231
2232	DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2233
2234	tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2235					    &tun_proto, 0);
2236	if (!tfile)
2237		return -ENOMEM;
 
 
 
 
 
 
2238	RCU_INIT_POINTER(tfile->tun, NULL);
2239	tfile->flags = 0;
2240	tfile->ifindex = 0;
2241
2242	init_waitqueue_head(&tfile->wq.wait);
2243	RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2244
2245	tfile->socket.file = file;
2246	tfile->socket.ops = &tun_socket_ops;
2247
2248	sock_init_data(&tfile->socket, &tfile->sk);
2249
2250	tfile->sk.sk_write_space = tun_sock_write_space;
2251	tfile->sk.sk_sndbuf = INT_MAX;
2252
2253	file->private_data = tfile;
2254	INIT_LIST_HEAD(&tfile->next);
2255
2256	sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2257
2258	return 0;
2259}
2260
2261static int tun_chr_close(struct inode *inode, struct file *file)
2262{
2263	struct tun_file *tfile = file->private_data;
2264
2265	tun_detach(tfile, true);
2266
2267	return 0;
2268}
2269
2270#ifdef CONFIG_PROC_FS
2271static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2272{
 
2273	struct tun_struct *tun;
2274	struct ifreq ifr;
2275
2276	memset(&ifr, 0, sizeof(ifr));
2277
2278	rtnl_lock();
2279	tun = tun_get(f);
2280	if (tun)
2281		tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2282	rtnl_unlock();
2283
2284	if (tun)
2285		tun_put(tun);
2286
2287	seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2288}
2289#endif
2290
2291static const struct file_operations tun_fops = {
2292	.owner	= THIS_MODULE,
2293	.llseek = no_llseek,
2294	.read_iter  = tun_chr_read_iter,
2295	.write_iter = tun_chr_write_iter,
2296	.poll	= tun_chr_poll,
2297	.unlocked_ioctl	= tun_chr_ioctl,
2298#ifdef CONFIG_COMPAT
2299	.compat_ioctl = tun_chr_compat_ioctl,
2300#endif
2301	.open	= tun_chr_open,
2302	.release = tun_chr_close,
2303	.fasync = tun_chr_fasync,
2304#ifdef CONFIG_PROC_FS
2305	.show_fdinfo = tun_chr_show_fdinfo,
2306#endif
2307};
2308
2309static struct miscdevice tun_miscdev = {
2310	.minor = TUN_MINOR,
2311	.name = "tun",
2312	.nodename = "net/tun",
2313	.fops = &tun_fops,
2314};
2315
2316/* ethtool interface */
2317
2318static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2319{
2320	cmd->supported		= 0;
2321	cmd->advertising	= 0;
2322	ethtool_cmd_speed_set(cmd, SPEED_10);
2323	cmd->duplex		= DUPLEX_FULL;
2324	cmd->port		= PORT_TP;
2325	cmd->phy_address	= 0;
2326	cmd->transceiver	= XCVR_INTERNAL;
2327	cmd->autoneg		= AUTONEG_DISABLE;
2328	cmd->maxtxpkt		= 0;
2329	cmd->maxrxpkt		= 0;
2330	return 0;
2331}
2332
2333static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2334{
2335	struct tun_struct *tun = netdev_priv(dev);
2336
2337	strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2338	strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2339
2340	switch (tun->flags & TUN_TYPE_MASK) {
2341	case IFF_TUN:
2342		strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2343		break;
2344	case IFF_TAP:
2345		strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2346		break;
2347	}
2348}
2349
2350static u32 tun_get_msglevel(struct net_device *dev)
2351{
2352#ifdef TUN_DEBUG
2353	struct tun_struct *tun = netdev_priv(dev);
2354	return tun->debug;
2355#else
2356	return -EOPNOTSUPP;
2357#endif
2358}
2359
2360static void tun_set_msglevel(struct net_device *dev, u32 value)
2361{
2362#ifdef TUN_DEBUG
2363	struct tun_struct *tun = netdev_priv(dev);
2364	tun->debug = value;
2365#endif
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2366}
2367
2368static const struct ethtool_ops tun_ethtool_ops = {
2369	.get_settings	= tun_get_settings,
2370	.get_drvinfo	= tun_get_drvinfo,
2371	.get_msglevel	= tun_get_msglevel,
2372	.set_msglevel	= tun_set_msglevel,
2373	.get_link	= ethtool_op_get_link,
2374	.get_ts_info	= ethtool_op_get_ts_info,
 
 
 
 
2375};
2376
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2377
2378static int __init tun_init(void)
2379{
2380	int ret = 0;
2381
2382	pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2383	pr_info("%s\n", DRV_COPYRIGHT);
2384
2385	ret = rtnl_link_register(&tun_link_ops);
2386	if (ret) {
2387		pr_err("Can't register link_ops\n");
2388		goto err_linkops;
2389	}
2390
2391	ret = misc_register(&tun_miscdev);
2392	if (ret) {
2393		pr_err("Can't register misc device %d\n", TUN_MINOR);
2394		goto err_misc;
2395	}
 
 
 
 
 
 
 
2396	return  0;
 
 
 
2397err_misc:
2398	rtnl_link_unregister(&tun_link_ops);
2399err_linkops:
2400	return ret;
2401}
2402
2403static void tun_cleanup(void)
2404{
2405	misc_deregister(&tun_miscdev);
2406	rtnl_link_unregister(&tun_link_ops);
 
2407}
2408
2409/* Get an underlying socket object from tun file.  Returns error unless file is
2410 * attached to a device.  The returned object works like a packet socket, it
2411 * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2412 * holding a reference to the file for as long as the socket is in use. */
2413struct socket *tun_get_socket(struct file *file)
2414{
2415	struct tun_file *tfile;
2416	if (file->f_op != &tun_fops)
2417		return ERR_PTR(-EINVAL);
2418	tfile = file->private_data;
2419	if (!tfile)
2420		return ERR_PTR(-EBADFD);
2421	return &tfile->socket;
2422}
2423EXPORT_SYMBOL_GPL(tun_get_socket);
 
 
 
 
 
 
 
 
 
 
 
 
 
2424
2425module_init(tun_init);
2426module_exit(tun_cleanup);
2427MODULE_DESCRIPTION(DRV_DESCRIPTION);
2428MODULE_AUTHOR(DRV_COPYRIGHT);
2429MODULE_LICENSE("GPL");
2430MODULE_ALIAS_MISCDEV(TUN_MINOR);
2431MODULE_ALIAS("devname:net/tun");