linux/drivers/net/tun.c
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   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 random_ether_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 DRV_NAME        "tun"
  38#define DRV_VERSION     "1.6"
  39#define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  40#define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
  41
  42#include <linux/module.h>
  43#include <linux/errno.h>
  44#include <linux/kernel.h>
  45#include <linux/major.h>
  46#include <linux/slab.h>
  47#include <linux/poll.h>
  48#include <linux/fcntl.h>
  49#include <linux/init.h>
  50#include <linux/skbuff.h>
  51#include <linux/netdevice.h>
  52#include <linux/etherdevice.h>
  53#include <linux/miscdevice.h>
  54#include <linux/ethtool.h>
  55#include <linux/rtnetlink.h>
  56#include <linux/compat.h>
  57#include <linux/if.h>
  58#include <linux/if_arp.h>
  59#include <linux/if_ether.h>
  60#include <linux/if_tun.h>
  61#include <linux/crc32.h>
  62#include <linux/nsproxy.h>
  63#include <linux/virtio_net.h>
  64#include <linux/rcupdate.h>
  65#include <net/net_namespace.h>
  66#include <net/netns/generic.h>
  67#include <net/rtnetlink.h>
  68#include <net/sock.h>
  69
  70#include <asm/system.h>
  71#include <asm/uaccess.h>
  72
  73/* Uncomment to enable debugging */
  74/* #define TUN_DEBUG 1 */
  75
  76#ifdef TUN_DEBUG
  77static int debug;
  78
  79#define DBG  if(tun->debug)printk
  80#define DBG1 if(debug==2)printk
  81#else
  82#define DBG( a... )
  83#define DBG1( a... )
  84#endif
  85
  86#define FLT_EXACT_COUNT 8
  87struct tap_filter {
  88        unsigned int    count;    /* Number of addrs. Zero means disabled */
  89        u32             mask[2];  /* Mask of the hashed addrs */
  90        unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
  91};
  92
  93struct tun_file {
  94        atomic_t count;
  95        struct tun_struct *tun;
  96        struct net *net;
  97};
  98
  99struct tun_sock;
 100
 101struct tun_struct {
 102        struct tun_file         *tfile;
 103        unsigned int            flags;
 104        uid_t                   owner;
 105        gid_t                   group;
 106
 107        struct net_device       *dev;
 108        struct fasync_struct    *fasync;
 109
 110        struct tap_filter       txflt;
 111        struct socket           socket;
 112        struct socket_wq        wq;
 113
 114        int                     vnet_hdr_sz;
 115
 116#ifdef TUN_DEBUG
 117        int debug;
 118#endif
 119};
 120
 121struct tun_sock {
 122        struct sock             sk;
 123        struct tun_struct       *tun;
 124};
 125
 126static inline struct tun_sock *tun_sk(struct sock *sk)
 127{
 128        return container_of(sk, struct tun_sock, sk);
 129}
 130
 131static int tun_attach(struct tun_struct *tun, struct file *file)
 132{
 133        struct tun_file *tfile = file->private_data;
 134        int err;
 135
 136        ASSERT_RTNL();
 137
 138        netif_tx_lock_bh(tun->dev);
 139
 140        err = -EINVAL;
 141        if (tfile->tun)
 142                goto out;
 143
 144        err = -EBUSY;
 145        if (tun->tfile)
 146                goto out;
 147
 148        err = 0;
 149        tfile->tun = tun;
 150        tun->tfile = tfile;
 151        tun->socket.file = file;
 152        netif_carrier_on(tun->dev);
 153        dev_hold(tun->dev);
 154        sock_hold(tun->socket.sk);
 155        atomic_inc(&tfile->count);
 156
 157out:
 158        netif_tx_unlock_bh(tun->dev);
 159        return err;
 160}
 161
 162static void __tun_detach(struct tun_struct *tun)
 163{
 164        /* Detach from net device */
 165        netif_tx_lock_bh(tun->dev);
 166        netif_carrier_off(tun->dev);
 167        tun->tfile = NULL;
 168        tun->socket.file = NULL;
 169        netif_tx_unlock_bh(tun->dev);
 170
 171        /* Drop read queue */
 172        skb_queue_purge(&tun->socket.sk->sk_receive_queue);
 173
 174        /* Drop the extra count on the net device */
 175        dev_put(tun->dev);
 176}
 177
 178static void tun_detach(struct tun_struct *tun)
 179{
 180        rtnl_lock();
 181        __tun_detach(tun);
 182        rtnl_unlock();
 183}
 184
 185static struct tun_struct *__tun_get(struct tun_file *tfile)
 186{
 187        struct tun_struct *tun = NULL;
 188
 189        if (atomic_inc_not_zero(&tfile->count))
 190                tun = tfile->tun;
 191
 192        return tun;
 193}
 194
 195static struct tun_struct *tun_get(struct file *file)
 196{
 197        return __tun_get(file->private_data);
 198}
 199
 200static void tun_put(struct tun_struct *tun)
 201{
 202        struct tun_file *tfile = tun->tfile;
 203
 204        if (atomic_dec_and_test(&tfile->count))
 205                tun_detach(tfile->tun);
 206}
 207
 208/* TAP filterting */
 209static void addr_hash_set(u32 *mask, const u8 *addr)
 210{
 211        int n = ether_crc(ETH_ALEN, addr) >> 26;
 212        mask[n >> 5] |= (1 << (n & 31));
 213}
 214
 215static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 216{
 217        int n = ether_crc(ETH_ALEN, addr) >> 26;
 218        return mask[n >> 5] & (1 << (n & 31));
 219}
 220
 221static int update_filter(struct tap_filter *filter, void __user *arg)
 222{
 223        struct { u8 u[ETH_ALEN]; } *addr;
 224        struct tun_filter uf;
 225        int err, alen, n, nexact;
 226
 227        if (copy_from_user(&uf, arg, sizeof(uf)))
 228                return -EFAULT;
 229
 230        if (!uf.count) {
 231                /* Disabled */
 232                filter->count = 0;
 233                return 0;
 234        }
 235
 236        alen = ETH_ALEN * uf.count;
 237        addr = kmalloc(alen, GFP_KERNEL);
 238        if (!addr)
 239                return -ENOMEM;
 240
 241        if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 242                err = -EFAULT;
 243                goto done;
 244        }
 245
 246        /* The filter is updated without holding any locks. Which is
 247         * perfectly safe. We disable it first and in the worst
 248         * case we'll accept a few undesired packets. */
 249        filter->count = 0;
 250        wmb();
 251
 252        /* Use first set of addresses as an exact filter */
 253        for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 254                memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 255
 256        nexact = n;
 257
 258        /* Remaining multicast addresses are hashed,
 259         * unicast will leave the filter disabled. */
 260        memset(filter->mask, 0, sizeof(filter->mask));
 261        for (; n < uf.count; n++) {
 262                if (!is_multicast_ether_addr(addr[n].u)) {
 263                        err = 0; /* no filter */
 264                        goto done;
 265                }
 266                addr_hash_set(filter->mask, addr[n].u);
 267        }
 268
 269        /* For ALLMULTI just set the mask to all ones.
 270         * This overrides the mask populated above. */
 271        if ((uf.flags & TUN_FLT_ALLMULTI))
 272                memset(filter->mask, ~0, sizeof(filter->mask));
 273
 274        /* Now enable the filter */
 275        wmb();
 276        filter->count = nexact;
 277
 278        /* Return the number of exact filters */
 279        err = nexact;
 280
 281done:
 282        kfree(addr);
 283        return err;
 284}
 285
 286/* Returns: 0 - drop, !=0 - accept */
 287static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 288{
 289        /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 290         * at this point. */
 291        struct ethhdr *eh = (struct ethhdr *) skb->data;
 292        int i;
 293
 294        /* Exact match */
 295        for (i = 0; i < filter->count; i++)
 296                if (!compare_ether_addr(eh->h_dest, filter->addr[i]))
 297                        return 1;
 298
 299        /* Inexact match (multicast only) */
 300        if (is_multicast_ether_addr(eh->h_dest))
 301                return addr_hash_test(filter->mask, eh->h_dest);
 302
 303        return 0;
 304}
 305
 306/*
 307 * Checks whether the packet is accepted or not.
 308 * Returns: 0 - drop, !=0 - accept
 309 */
 310static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 311{
 312        if (!filter->count)
 313                return 1;
 314
 315        return run_filter(filter, skb);
 316}
 317
 318/* Network device part of the driver */
 319
 320static const struct ethtool_ops tun_ethtool_ops;
 321
 322/* Net device detach from fd. */
 323static void tun_net_uninit(struct net_device *dev)
 324{
 325        struct tun_struct *tun = netdev_priv(dev);
 326        struct tun_file *tfile = tun->tfile;
 327
 328        /* Inform the methods they need to stop using the dev.
 329         */
 330        if (tfile) {
 331                wake_up_all(&tun->wq.wait);
 332                if (atomic_dec_and_test(&tfile->count))
 333                        __tun_detach(tun);
 334        }
 335}
 336
 337static void tun_free_netdev(struct net_device *dev)
 338{
 339        struct tun_struct *tun = netdev_priv(dev);
 340
 341        sock_put(tun->socket.sk);
 342}
 343
 344/* Net device open. */
 345static int tun_net_open(struct net_device *dev)
 346{
 347        netif_start_queue(dev);
 348        return 0;
 349}
 350
 351/* Net device close. */
 352static int tun_net_close(struct net_device *dev)
 353{
 354        netif_stop_queue(dev);
 355        return 0;
 356}
 357
 358/* Net device start xmit */
 359static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 360{
 361        struct tun_struct *tun = netdev_priv(dev);
 362
 363        DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
 364
 365        /* Drop packet if interface is not attached */
 366        if (!tun->tfile)
 367                goto drop;
 368
 369        /* Drop if the filter does not like it.
 370         * This is a noop if the filter is disabled.
 371         * Filter can be enabled only for the TAP devices. */
 372        if (!check_filter(&tun->txflt, skb))
 373                goto drop;
 374
 375        if (tun->socket.sk->sk_filter &&
 376            sk_filter(tun->socket.sk, skb))
 377                goto drop;
 378
 379        if (skb_queue_len(&tun->socket.sk->sk_receive_queue) >= dev->tx_queue_len) {
 380                if (!(tun->flags & TUN_ONE_QUEUE)) {
 381                        /* Normal queueing mode. */
 382                        /* Packet scheduler handles dropping of further packets. */
 383                        netif_stop_queue(dev);
 384
 385                        /* We won't see all dropped packets individually, so overrun
 386                         * error is more appropriate. */
 387                        dev->stats.tx_fifo_errors++;
 388                } else {
 389                        /* Single queue mode.
 390                         * Driver handles dropping of all packets itself. */
 391                        goto drop;
 392                }
 393        }
 394
 395        /* Orphan the skb - required as we might hang on to it
 396         * for indefinite time. */
 397        skb_orphan(skb);
 398
 399        /* Enqueue packet */
 400        skb_queue_tail(&tun->socket.sk->sk_receive_queue, skb);
 401
 402        /* Notify and wake up reader process */
 403        if (tun->flags & TUN_FASYNC)
 404                kill_fasync(&tun->fasync, SIGIO, POLL_IN);
 405        wake_up_interruptible_poll(&tun->wq.wait, POLLIN |
 406                                   POLLRDNORM | POLLRDBAND);
 407        return NETDEV_TX_OK;
 408
 409drop:
 410        dev->stats.tx_dropped++;
 411        kfree_skb(skb);
 412        return NETDEV_TX_OK;
 413}
 414
 415static void tun_net_mclist(struct net_device *dev)
 416{
 417        /*
 418         * This callback is supposed to deal with mc filter in
 419         * _rx_ path and has nothing to do with the _tx_ path.
 420         * In rx path we always accept everything userspace gives us.
 421         */
 422}
 423
 424#define MIN_MTU 68
 425#define MAX_MTU 65535
 426
 427static int
 428tun_net_change_mtu(struct net_device *dev, int new_mtu)
 429{
 430        if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 431                return -EINVAL;
 432        dev->mtu = new_mtu;
 433        return 0;
 434}
 435
 436static const struct net_device_ops tun_netdev_ops = {
 437        .ndo_uninit             = tun_net_uninit,
 438        .ndo_open               = tun_net_open,
 439        .ndo_stop               = tun_net_close,
 440        .ndo_start_xmit         = tun_net_xmit,
 441        .ndo_change_mtu         = tun_net_change_mtu,
 442};
 443
 444static const struct net_device_ops tap_netdev_ops = {
 445        .ndo_uninit             = tun_net_uninit,
 446        .ndo_open               = tun_net_open,
 447        .ndo_stop               = tun_net_close,
 448        .ndo_start_xmit         = tun_net_xmit,
 449        .ndo_change_mtu         = tun_net_change_mtu,
 450        .ndo_set_multicast_list = tun_net_mclist,
 451        .ndo_set_mac_address    = eth_mac_addr,
 452        .ndo_validate_addr      = eth_validate_addr,
 453};
 454
 455/* Initialize net device. */
 456static void tun_net_init(struct net_device *dev)
 457{
 458        struct tun_struct *tun = netdev_priv(dev);
 459
 460        switch (tun->flags & TUN_TYPE_MASK) {
 461        case TUN_TUN_DEV:
 462                dev->netdev_ops = &tun_netdev_ops;
 463
 464                /* Point-to-Point TUN Device */
 465                dev->hard_header_len = 0;
 466                dev->addr_len = 0;
 467                dev->mtu = 1500;
 468
 469                /* Zero header length */
 470                dev->type = ARPHRD_NONE;
 471                dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 472                dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 473                break;
 474
 475        case TUN_TAP_DEV:
 476                dev->netdev_ops = &tap_netdev_ops;
 477                /* Ethernet TAP Device */
 478                ether_setup(dev);
 479
 480                random_ether_addr(dev->dev_addr);
 481
 482                dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 483                break;
 484        }
 485}
 486
 487/* Character device part */
 488
 489/* Poll */
 490static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
 491{
 492        struct tun_file *tfile = file->private_data;
 493        struct tun_struct *tun = __tun_get(tfile);
 494        struct sock *sk;
 495        unsigned int mask = 0;
 496
 497        if (!tun)
 498                return POLLERR;
 499
 500        sk = tun->socket.sk;
 501
 502        DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
 503
 504        poll_wait(file, &tun->wq.wait, wait);
 505
 506        if (!skb_queue_empty(&sk->sk_receive_queue))
 507                mask |= POLLIN | POLLRDNORM;
 508
 509        if (sock_writeable(sk) ||
 510            (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 511             sock_writeable(sk)))
 512                mask |= POLLOUT | POLLWRNORM;
 513
 514        if (tun->dev->reg_state != NETREG_REGISTERED)
 515                mask = POLLERR;
 516
 517        tun_put(tun);
 518        return mask;
 519}
 520
 521/* prepad is the amount to reserve at front.  len is length after that.
 522 * linear is a hint as to how much to copy (usually headers). */
 523static inline struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
 524                                            size_t prepad, size_t len,
 525                                            size_t linear, int noblock)
 526{
 527        struct sock *sk = tun->socket.sk;
 528        struct sk_buff *skb;
 529        int err;
 530
 531        sock_update_classid(sk);
 532
 533        /* Under a page?  Don't bother with paged skb. */
 534        if (prepad + len < PAGE_SIZE || !linear)
 535                linear = len;
 536
 537        skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 538                                   &err);
 539        if (!skb)
 540                return ERR_PTR(err);
 541
 542        skb_reserve(skb, prepad);
 543        skb_put(skb, linear);
 544        skb->data_len = len - linear;
 545        skb->len += len - linear;
 546
 547        return skb;
 548}
 549
 550/* Get packet from user space buffer */
 551static __inline__ ssize_t tun_get_user(struct tun_struct *tun,
 552                                       const struct iovec *iv, size_t count,
 553                                       int noblock)
 554{
 555        struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
 556        struct sk_buff *skb;
 557        size_t len = count, align = 0;
 558        struct virtio_net_hdr gso = { 0 };
 559        int offset = 0;
 560
 561        if (!(tun->flags & TUN_NO_PI)) {
 562                if ((len -= sizeof(pi)) > count)
 563                        return -EINVAL;
 564
 565                if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
 566                        return -EFAULT;
 567                offset += sizeof(pi);
 568        }
 569
 570        if (tun->flags & TUN_VNET_HDR) {
 571                if ((len -= tun->vnet_hdr_sz) > count)
 572                        return -EINVAL;
 573
 574                if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
 575                        return -EFAULT;
 576
 577                if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
 578                    gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
 579                        gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
 580
 581                if (gso.hdr_len > len)
 582                        return -EINVAL;
 583                offset += tun->vnet_hdr_sz;
 584        }
 585
 586        if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
 587                align = NET_IP_ALIGN;
 588                if (unlikely(len < ETH_HLEN ||
 589                             (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
 590                        return -EINVAL;
 591        }
 592
 593        skb = tun_alloc_skb(tun, align, len, gso.hdr_len, noblock);
 594        if (IS_ERR(skb)) {
 595                if (PTR_ERR(skb) != -EAGAIN)
 596                        tun->dev->stats.rx_dropped++;
 597                return PTR_ERR(skb);
 598        }
 599
 600        if (skb_copy_datagram_from_iovec(skb, 0, iv, offset, len)) {
 601                tun->dev->stats.rx_dropped++;
 602                kfree_skb(skb);
 603                return -EFAULT;
 604        }
 605
 606        if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 607                if (!skb_partial_csum_set(skb, gso.csum_start,
 608                                          gso.csum_offset)) {
 609                        tun->dev->stats.rx_frame_errors++;
 610                        kfree_skb(skb);
 611                        return -EINVAL;
 612                }
 613        } else if (tun->flags & TUN_NOCHECKSUM)
 614                skb->ip_summed = CHECKSUM_UNNECESSARY;
 615
 616        switch (tun->flags & TUN_TYPE_MASK) {
 617        case TUN_TUN_DEV:
 618                if (tun->flags & TUN_NO_PI) {
 619                        switch (skb->data[0] & 0xf0) {
 620                        case 0x40:
 621                                pi.proto = htons(ETH_P_IP);
 622                                break;
 623                        case 0x60:
 624                                pi.proto = htons(ETH_P_IPV6);
 625                                break;
 626                        default:
 627                                tun->dev->stats.rx_dropped++;
 628                                kfree_skb(skb);
 629                                return -EINVAL;
 630                        }
 631                }
 632
 633                skb_reset_mac_header(skb);
 634                skb->protocol = pi.proto;
 635                skb->dev = tun->dev;
 636                break;
 637        case TUN_TAP_DEV:
 638                skb->protocol = eth_type_trans(skb, tun->dev);
 639                break;
 640        };
 641
 642        if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 643                pr_debug("GSO!\n");
 644                switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 645                case VIRTIO_NET_HDR_GSO_TCPV4:
 646                        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 647                        break;
 648                case VIRTIO_NET_HDR_GSO_TCPV6:
 649                        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 650                        break;
 651                case VIRTIO_NET_HDR_GSO_UDP:
 652                        skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 653                        break;
 654                default:
 655                        tun->dev->stats.rx_frame_errors++;
 656                        kfree_skb(skb);
 657                        return -EINVAL;
 658                }
 659
 660                if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 661                        skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 662
 663                skb_shinfo(skb)->gso_size = gso.gso_size;
 664                if (skb_shinfo(skb)->gso_size == 0) {
 665                        tun->dev->stats.rx_frame_errors++;
 666                        kfree_skb(skb);
 667                        return -EINVAL;
 668                }
 669
 670                /* Header must be checked, and gso_segs computed. */
 671                skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 672                skb_shinfo(skb)->gso_segs = 0;
 673        }
 674
 675        netif_rx_ni(skb);
 676
 677        tun->dev->stats.rx_packets++;
 678        tun->dev->stats.rx_bytes += len;
 679
 680        return count;
 681}
 682
 683static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 684                              unsigned long count, loff_t pos)
 685{
 686        struct file *file = iocb->ki_filp;
 687        struct tun_struct *tun = tun_get(file);
 688        ssize_t result;
 689
 690        if (!tun)
 691                return -EBADFD;
 692
 693        DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 694
 695        result = tun_get_user(tun, iv, iov_length(iv, count),
 696                              file->f_flags & O_NONBLOCK);
 697
 698        tun_put(tun);
 699        return result;
 700}
 701
 702/* Put packet to the user space buffer */
 703static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
 704                                       struct sk_buff *skb,
 705                                       const struct iovec *iv, int len)
 706{
 707        struct tun_pi pi = { 0, skb->protocol };
 708        ssize_t total = 0;
 709
 710        if (!(tun->flags & TUN_NO_PI)) {
 711                if ((len -= sizeof(pi)) < 0)
 712                        return -EINVAL;
 713
 714                if (len < skb->len) {
 715                        /* Packet will be striped */
 716                        pi.flags |= TUN_PKT_STRIP;
 717                }
 718
 719                if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
 720                        return -EFAULT;
 721                total += sizeof(pi);
 722        }
 723
 724        if (tun->flags & TUN_VNET_HDR) {
 725                struct virtio_net_hdr gso = { 0 }; /* no info leak */
 726                if ((len -= tun->vnet_hdr_sz) < 0)
 727                        return -EINVAL;
 728
 729                if (skb_is_gso(skb)) {
 730                        struct skb_shared_info *sinfo = skb_shinfo(skb);
 731
 732                        /* This is a hint as to how much should be linear. */
 733                        gso.hdr_len = skb_headlen(skb);
 734                        gso.gso_size = sinfo->gso_size;
 735                        if (sinfo->gso_type & SKB_GSO_TCPV4)
 736                                gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 737                        else if (sinfo->gso_type & SKB_GSO_TCPV6)
 738                                gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 739                        else if (sinfo->gso_type & SKB_GSO_UDP)
 740                                gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 741                        else {
 742                                printk(KERN_ERR "tun: unexpected GSO type: "
 743                                       "0x%x, gso_size %d, hdr_len %d\n",
 744                                       sinfo->gso_type, gso.gso_size,
 745                                       gso.hdr_len);
 746                                print_hex_dump(KERN_ERR, "tun: ",
 747                                               DUMP_PREFIX_NONE,
 748                                               16, 1, skb->head,
 749                                               min((int)gso.hdr_len, 64), true);
 750                                WARN_ON_ONCE(1);
 751                                return -EINVAL;
 752                        }
 753                        if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 754                                gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 755                } else
 756                        gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 757
 758                if (skb->ip_summed == CHECKSUM_PARTIAL) {
 759                        gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 760                        gso.csum_start = skb->csum_start - skb_headroom(skb);
 761                        gso.csum_offset = skb->csum_offset;
 762                } /* else everything is zero */
 763
 764                if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
 765                                               sizeof(gso))))
 766                        return -EFAULT;
 767                total += tun->vnet_hdr_sz;
 768        }
 769
 770        len = min_t(int, skb->len, len);
 771
 772        skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
 773        total += skb->len;
 774
 775        tun->dev->stats.tx_packets++;
 776        tun->dev->stats.tx_bytes += len;
 777
 778        return total;
 779}
 780
 781static ssize_t tun_do_read(struct tun_struct *tun,
 782                           struct kiocb *iocb, const struct iovec *iv,
 783                           ssize_t len, int noblock)
 784{
 785        DECLARE_WAITQUEUE(wait, current);
 786        struct sk_buff *skb;
 787        ssize_t ret = 0;
 788
 789        DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 790
 791        add_wait_queue(&tun->wq.wait, &wait);
 792        while (len) {
 793                current->state = TASK_INTERRUPTIBLE;
 794
 795                /* Read frames from the queue */
 796                if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) {
 797                        if (noblock) {
 798                                ret = -EAGAIN;
 799                                break;
 800                        }
 801                        if (signal_pending(current)) {
 802                                ret = -ERESTARTSYS;
 803                                break;
 804                        }
 805                        if (tun->dev->reg_state != NETREG_REGISTERED) {
 806                                ret = -EIO;
 807                                break;
 808                        }
 809
 810                        /* Nothing to read, let's sleep */
 811                        schedule();
 812                        continue;
 813                }
 814                netif_wake_queue(tun->dev);
 815
 816                ret = tun_put_user(tun, skb, iv, len);
 817                kfree_skb(skb);
 818                break;
 819        }
 820
 821        current->state = TASK_RUNNING;
 822        remove_wait_queue(&tun->wq.wait, &wait);
 823
 824        return ret;
 825}
 826
 827static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 828                            unsigned long count, loff_t pos)
 829{
 830        struct file *file = iocb->ki_filp;
 831        struct tun_file *tfile = file->private_data;
 832        struct tun_struct *tun = __tun_get(tfile);
 833        ssize_t len, ret;
 834
 835        if (!tun)
 836                return -EBADFD;
 837        len = iov_length(iv, count);
 838        if (len < 0) {
 839                ret = -EINVAL;
 840                goto out;
 841        }
 842
 843        ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK);
 844        ret = min_t(ssize_t, ret, len);
 845out:
 846        tun_put(tun);
 847        return ret;
 848}
 849
 850static void tun_setup(struct net_device *dev)
 851{
 852        struct tun_struct *tun = netdev_priv(dev);
 853
 854        tun->owner = -1;
 855        tun->group = -1;
 856
 857        dev->ethtool_ops = &tun_ethtool_ops;
 858        dev->destructor = tun_free_netdev;
 859}
 860
 861/* Trivial set of netlink ops to allow deleting tun or tap
 862 * device with netlink.
 863 */
 864static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
 865{
 866        return -EINVAL;
 867}
 868
 869static struct rtnl_link_ops tun_link_ops __read_mostly = {
 870        .kind           = DRV_NAME,
 871        .priv_size      = sizeof(struct tun_struct),
 872        .setup          = tun_setup,
 873        .validate       = tun_validate,
 874};
 875
 876static void tun_sock_write_space(struct sock *sk)
 877{
 878        struct tun_struct *tun;
 879        wait_queue_head_t *wqueue;
 880
 881        if (!sock_writeable(sk))
 882                return;
 883
 884        if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
 885                return;
 886
 887        wqueue = sk_sleep(sk);
 888        if (wqueue && waitqueue_active(wqueue))
 889                wake_up_interruptible_sync_poll(wqueue, POLLOUT |
 890                                                POLLWRNORM | POLLWRBAND);
 891
 892        tun = tun_sk(sk)->tun;
 893        kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
 894}
 895
 896static void tun_sock_destruct(struct sock *sk)
 897{
 898        free_netdev(tun_sk(sk)->tun->dev);
 899}
 900
 901static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
 902                       struct msghdr *m, size_t total_len)
 903{
 904        struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
 905        return tun_get_user(tun, m->msg_iov, total_len,
 906                            m->msg_flags & MSG_DONTWAIT);
 907}
 908
 909static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
 910                       struct msghdr *m, size_t total_len,
 911                       int flags)
 912{
 913        struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
 914        int ret;
 915        if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
 916                return -EINVAL;
 917        ret = tun_do_read(tun, iocb, m->msg_iov, total_len,
 918                          flags & MSG_DONTWAIT);
 919        if (ret > total_len) {
 920                m->msg_flags |= MSG_TRUNC;
 921                ret = flags & MSG_TRUNC ? ret : total_len;
 922        }
 923        return ret;
 924}
 925
 926/* Ops structure to mimic raw sockets with tun */
 927static const struct proto_ops tun_socket_ops = {
 928        .sendmsg = tun_sendmsg,
 929        .recvmsg = tun_recvmsg,
 930};
 931
 932static struct proto tun_proto = {
 933        .name           = "tun",
 934        .owner          = THIS_MODULE,
 935        .obj_size       = sizeof(struct tun_sock),
 936};
 937
 938static int tun_flags(struct tun_struct *tun)
 939{
 940        int flags = 0;
 941
 942        if (tun->flags & TUN_TUN_DEV)
 943                flags |= IFF_TUN;
 944        else
 945                flags |= IFF_TAP;
 946
 947        if (tun->flags & TUN_NO_PI)
 948                flags |= IFF_NO_PI;
 949
 950        if (tun->flags & TUN_ONE_QUEUE)
 951                flags |= IFF_ONE_QUEUE;
 952
 953        if (tun->flags & TUN_VNET_HDR)
 954                flags |= IFF_VNET_HDR;
 955
 956        return flags;
 957}
 958
 959static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
 960                              char *buf)
 961{
 962        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
 963        return sprintf(buf, "0x%x\n", tun_flags(tun));
 964}
 965
 966static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
 967                              char *buf)
 968{
 969        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
 970        return sprintf(buf, "%d\n", tun->owner);
 971}
 972
 973static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
 974                              char *buf)
 975{
 976        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
 977        return sprintf(buf, "%d\n", tun->group);
 978}
 979
 980static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
 981static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
 982static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
 983
 984static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 985{
 986        struct sock *sk;
 987        struct tun_struct *tun;
 988        struct net_device *dev;
 989        int err;
 990
 991        dev = __dev_get_by_name(net, ifr->ifr_name);
 992        if (dev) {
 993                const struct cred *cred = current_cred();
 994
 995                if (ifr->ifr_flags & IFF_TUN_EXCL)
 996                        return -EBUSY;
 997                if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
 998                        tun = netdev_priv(dev);
 999                else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1000                        tun = netdev_priv(dev);
1001                else
1002                        return -EINVAL;
1003
1004                if (((tun->owner != -1 && cred->euid != tun->owner) ||
1005                     (tun->group != -1 && !in_egroup_p(tun->group))) &&
1006                    !capable(CAP_NET_ADMIN))
1007                        return -EPERM;
1008                err = security_tun_dev_attach(tun->socket.sk);
1009                if (err < 0)
1010                        return err;
1011
1012                err = tun_attach(tun, file);
1013                if (err < 0)
1014                        return err;
1015        }
1016        else {
1017                char *name;
1018                unsigned long flags = 0;
1019
1020                if (!capable(CAP_NET_ADMIN))
1021                        return -EPERM;
1022                err = security_tun_dev_create();
1023                if (err < 0)
1024                        return err;
1025
1026                /* Set dev type */
1027                if (ifr->ifr_flags & IFF_TUN) {
1028                        /* TUN device */
1029                        flags |= TUN_TUN_DEV;
1030                        name = "tun%d";
1031                } else if (ifr->ifr_flags & IFF_TAP) {
1032                        /* TAP device */
1033                        flags |= TUN_TAP_DEV;
1034                        name = "tap%d";
1035                } else
1036                        return -EINVAL;
1037
1038                if (*ifr->ifr_name)
1039                        name = ifr->ifr_name;
1040
1041                dev = alloc_netdev(sizeof(struct tun_struct), name,
1042                                   tun_setup);
1043                if (!dev)
1044                        return -ENOMEM;
1045
1046                dev_net_set(dev, net);
1047                dev->rtnl_link_ops = &tun_link_ops;
1048
1049                tun = netdev_priv(dev);
1050                tun->dev = dev;
1051                tun->flags = flags;
1052                tun->txflt.count = 0;
1053                tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1054
1055                err = -ENOMEM;
1056                sk = sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
1057                if (!sk)
1058                        goto err_free_dev;
1059
1060                tun->socket.wq = &tun->wq;
1061                init_waitqueue_head(&tun->wq.wait);
1062                tun->socket.ops = &tun_socket_ops;
1063                sock_init_data(&tun->socket, sk);
1064                sk->sk_write_space = tun_sock_write_space;
1065                sk->sk_sndbuf = INT_MAX;
1066
1067                tun_sk(sk)->tun = tun;
1068
1069                security_tun_dev_post_create(sk);
1070
1071                tun_net_init(dev);
1072
1073                if (strchr(dev->name, '%')) {
1074                        err = dev_alloc_name(dev, dev->name);
1075                        if (err < 0)
1076                                goto err_free_sk;
1077                }
1078
1079                err = register_netdevice(tun->dev);
1080                if (err < 0)
1081                        goto err_free_sk;
1082
1083                if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1084                    device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1085                    device_create_file(&tun->dev->dev, &dev_attr_group))
1086                        printk(KERN_ERR "Failed to create tun sysfs files\n");
1087
1088                sk->sk_destruct = tun_sock_destruct;
1089
1090                err = tun_attach(tun, file);
1091                if (err < 0)
1092                        goto failed;
1093        }
1094
1095        DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
1096
1097        if (ifr->ifr_flags & IFF_NO_PI)
1098                tun->flags |= TUN_NO_PI;
1099        else
1100                tun->flags &= ~TUN_NO_PI;
1101
1102        if (ifr->ifr_flags & IFF_ONE_QUEUE)
1103                tun->flags |= TUN_ONE_QUEUE;
1104        else
1105                tun->flags &= ~TUN_ONE_QUEUE;
1106
1107        if (ifr->ifr_flags & IFF_VNET_HDR)
1108                tun->flags |= TUN_VNET_HDR;
1109        else
1110                tun->flags &= ~TUN_VNET_HDR;
1111
1112        /* Make sure persistent devices do not get stuck in
1113         * xoff state.
1114         */
1115        if (netif_running(tun->dev))
1116                netif_wake_queue(tun->dev);
1117
1118        strcpy(ifr->ifr_name, tun->dev->name);
1119        return 0;
1120
1121 err_free_sk:
1122        sock_put(sk);
1123 err_free_dev:
1124        free_netdev(dev);
1125 failed:
1126        return err;
1127}
1128
1129static int tun_get_iff(struct net *net, struct tun_struct *tun,
1130                       struct ifreq *ifr)
1131{
1132        DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
1133
1134        strcpy(ifr->ifr_name, tun->dev->name);
1135
1136        ifr->ifr_flags = tun_flags(tun);
1137
1138        return 0;
1139}
1140
1141/* This is like a cut-down ethtool ops, except done via tun fd so no
1142 * privs required. */
1143static int set_offload(struct net_device *dev, unsigned long arg)
1144{
1145        unsigned int old_features, features;
1146
1147        old_features = dev->features;
1148        /* Unset features, set them as we chew on the arg. */
1149        features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
1150                                    |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6
1151                                    |NETIF_F_UFO));
1152
1153        if (arg & TUN_F_CSUM) {
1154                features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1155                arg &= ~TUN_F_CSUM;
1156
1157                if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1158                        if (arg & TUN_F_TSO_ECN) {
1159                                features |= NETIF_F_TSO_ECN;
1160                                arg &= ~TUN_F_TSO_ECN;
1161                        }
1162                        if (arg & TUN_F_TSO4)
1163                                features |= NETIF_F_TSO;
1164                        if (arg & TUN_F_TSO6)
1165                                features |= NETIF_F_TSO6;
1166                        arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1167                }
1168
1169                if (arg & TUN_F_UFO) {
1170                        features |= NETIF_F_UFO;
1171                        arg &= ~TUN_F_UFO;
1172                }
1173        }
1174
1175        /* This gives the user a way to test for new features in future by
1176         * trying to set them. */
1177        if (arg)
1178                return -EINVAL;
1179
1180        dev->features = features;
1181        if (old_features != dev->features)
1182                netdev_features_change(dev);
1183
1184        return 0;
1185}
1186
1187static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1188                            unsigned long arg, int ifreq_len)
1189{
1190        struct tun_file *tfile = file->private_data;
1191        struct tun_struct *tun;
1192        void __user* argp = (void __user*)arg;
1193        struct sock_fprog fprog;
1194        struct ifreq ifr;
1195        int sndbuf;
1196        int vnet_hdr_sz;
1197        int ret;
1198
1199        if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
1200                if (copy_from_user(&ifr, argp, ifreq_len))
1201                        return -EFAULT;
1202
1203        if (cmd == TUNGETFEATURES) {
1204                /* Currently this just means: "what IFF flags are valid?".
1205                 * This is needed because we never checked for invalid flags on
1206                 * TUNSETIFF. */
1207                return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1208                                IFF_VNET_HDR,
1209                                (unsigned int __user*)argp);
1210        }
1211
1212        rtnl_lock();
1213
1214        tun = __tun_get(tfile);
1215        if (cmd == TUNSETIFF && !tun) {
1216                ifr.ifr_name[IFNAMSIZ-1] = '\0';
1217
1218                ret = tun_set_iff(tfile->net, file, &ifr);
1219
1220                if (ret)
1221                        goto unlock;
1222
1223                if (copy_to_user(argp, &ifr, ifreq_len))
1224                        ret = -EFAULT;
1225                goto unlock;
1226        }
1227
1228        ret = -EBADFD;
1229        if (!tun)
1230                goto unlock;
1231
1232        DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
1233
1234        ret = 0;
1235        switch (cmd) {
1236        case TUNGETIFF:
1237                ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1238                if (ret)
1239                        break;
1240
1241                if (copy_to_user(argp, &ifr, ifreq_len))
1242                        ret = -EFAULT;
1243                break;
1244
1245        case TUNSETNOCSUM:
1246                /* Disable/Enable checksum */
1247                if (arg)
1248                        tun->flags |= TUN_NOCHECKSUM;
1249                else
1250                        tun->flags &= ~TUN_NOCHECKSUM;
1251
1252                DBG(KERN_INFO "%s: checksum %s\n",
1253                    tun->dev->name, arg ? "disabled" : "enabled");
1254                break;
1255
1256        case TUNSETPERSIST:
1257                /* Disable/Enable persist mode */
1258                if (arg)
1259                        tun->flags |= TUN_PERSIST;
1260                else
1261                        tun->flags &= ~TUN_PERSIST;
1262
1263                DBG(KERN_INFO "%s: persist %s\n",
1264                    tun->dev->name, arg ? "enabled" : "disabled");
1265                break;
1266
1267        case TUNSETOWNER:
1268                /* Set owner of the device */
1269                tun->owner = (uid_t) arg;
1270
1271                DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
1272                break;
1273
1274        case TUNSETGROUP:
1275                /* Set group of the device */
1276                tun->group= (gid_t) arg;
1277
1278                DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
1279                break;
1280
1281        case TUNSETLINK:
1282                /* Only allow setting the type when the interface is down */
1283                if (tun->dev->flags & IFF_UP) {
1284                        DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
1285                                tun->dev->name);
1286                        ret = -EBUSY;
1287                } else {
1288                        tun->dev->type = (int) arg;
1289                        DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
1290                        ret = 0;
1291                }
1292                break;
1293
1294#ifdef TUN_DEBUG
1295        case TUNSETDEBUG:
1296                tun->debug = arg;
1297                break;
1298#endif
1299        case TUNSETOFFLOAD:
1300                ret = set_offload(tun->dev, arg);
1301                break;
1302
1303        case TUNSETTXFILTER:
1304                /* Can be set only for TAPs */
1305                ret = -EINVAL;
1306                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1307                        break;
1308                ret = update_filter(&tun->txflt, (void __user *)arg);
1309                break;
1310
1311        case SIOCGIFHWADDR:
1312                /* Get hw addres */
1313                memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1314                ifr.ifr_hwaddr.sa_family = tun->dev->type;
1315                if (copy_to_user(argp, &ifr, ifreq_len))
1316                        ret = -EFAULT;
1317                break;
1318
1319        case SIOCSIFHWADDR:
1320                /* Set hw address */
1321                DBG(KERN_DEBUG "%s: set hw address: %pM\n",
1322                        tun->dev->name, ifr.ifr_hwaddr.sa_data);
1323
1324                ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1325                break;
1326
1327        case TUNGETSNDBUF:
1328                sndbuf = tun->socket.sk->sk_sndbuf;
1329                if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1330                        ret = -EFAULT;
1331                break;
1332
1333        case TUNSETSNDBUF:
1334                if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1335                        ret = -EFAULT;
1336                        break;
1337                }
1338
1339                tun->socket.sk->sk_sndbuf = sndbuf;
1340                break;
1341
1342        case TUNGETVNETHDRSZ:
1343                vnet_hdr_sz = tun->vnet_hdr_sz;
1344                if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
1345                        ret = -EFAULT;
1346                break;
1347
1348        case TUNSETVNETHDRSZ:
1349                if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
1350                        ret = -EFAULT;
1351                        break;
1352                }
1353                if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
1354                        ret = -EINVAL;
1355                        break;
1356                }
1357
1358                tun->vnet_hdr_sz = vnet_hdr_sz;
1359                break;
1360
1361        case TUNATTACHFILTER:
1362                /* Can be set only for TAPs */
1363                ret = -EINVAL;
1364                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1365                        break;
1366                ret = -EFAULT;
1367                if (copy_from_user(&fprog, argp, sizeof(fprog)))
1368                        break;
1369
1370                ret = sk_attach_filter(&fprog, tun->socket.sk);
1371                break;
1372
1373        case TUNDETACHFILTER:
1374                /* Can be set only for TAPs */
1375                ret = -EINVAL;
1376                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1377                        break;
1378                ret = sk_detach_filter(tun->socket.sk);
1379                break;
1380
1381        default:
1382                ret = -EINVAL;
1383                break;
1384        }
1385
1386unlock:
1387        rtnl_unlock();
1388        if (tun)
1389                tun_put(tun);
1390        return ret;
1391}
1392
1393static long tun_chr_ioctl(struct file *file,
1394                          unsigned int cmd, unsigned long arg)
1395{
1396        return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
1397}
1398
1399#ifdef CONFIG_COMPAT
1400static long tun_chr_compat_ioctl(struct file *file,
1401                         unsigned int cmd, unsigned long arg)
1402{
1403        switch (cmd) {
1404        case TUNSETIFF:
1405        case TUNGETIFF:
1406        case TUNSETTXFILTER:
1407        case TUNGETSNDBUF:
1408        case TUNSETSNDBUF:
1409        case SIOCGIFHWADDR:
1410        case SIOCSIFHWADDR:
1411                arg = (unsigned long)compat_ptr(arg);
1412                break;
1413        default:
1414                arg = (compat_ulong_t)arg;
1415                break;
1416        }
1417
1418        /*
1419         * compat_ifreq is shorter than ifreq, so we must not access beyond
1420         * the end of that structure. All fields that are used in this
1421         * driver are compatible though, we don't need to convert the
1422         * contents.
1423         */
1424        return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
1425}
1426#endif /* CONFIG_COMPAT */
1427
1428static int tun_chr_fasync(int fd, struct file *file, int on)
1429{
1430        struct tun_struct *tun = tun_get(file);
1431        int ret;
1432
1433        if (!tun)
1434                return -EBADFD;
1435
1436        DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
1437
1438        if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1439                goto out;
1440
1441        if (on) {
1442                ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1443                if (ret)
1444                        goto out;
1445                tun->flags |= TUN_FASYNC;
1446        } else
1447                tun->flags &= ~TUN_FASYNC;
1448        ret = 0;
1449out:
1450        tun_put(tun);
1451        return ret;
1452}
1453
1454static int tun_chr_open(struct inode *inode, struct file * file)
1455{
1456        struct tun_file *tfile;
1457
1458        DBG1(KERN_INFO "tunX: tun_chr_open\n");
1459
1460        tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1461        if (!tfile)
1462                return -ENOMEM;
1463        atomic_set(&tfile->count, 0);
1464        tfile->tun = NULL;
1465        tfile->net = get_net(current->nsproxy->net_ns);
1466        file->private_data = tfile;
1467        return 0;
1468}
1469
1470static int tun_chr_close(struct inode *inode, struct file *file)
1471{
1472        struct tun_file *tfile = file->private_data;
1473        struct tun_struct *tun;
1474
1475        tun = __tun_get(tfile);
1476        if (tun) {
1477                struct net_device *dev = tun->dev;
1478
1479                DBG(KERN_INFO "%s: tun_chr_close\n", dev->name);
1480
1481                __tun_detach(tun);
1482
1483                /* If desirable, unregister the netdevice. */
1484                if (!(tun->flags & TUN_PERSIST)) {
1485                        rtnl_lock();
1486                        if (dev->reg_state == NETREG_REGISTERED)
1487                                unregister_netdevice(dev);
1488                        rtnl_unlock();
1489                }
1490        }
1491
1492        tun = tfile->tun;
1493        if (tun)
1494                sock_put(tun->socket.sk);
1495
1496        put_net(tfile->net);
1497        kfree(tfile);
1498
1499        return 0;
1500}
1501
1502static const struct file_operations tun_fops = {
1503        .owner  = THIS_MODULE,
1504        .llseek = no_llseek,
1505        .read  = do_sync_read,
1506        .aio_read  = tun_chr_aio_read,
1507        .write = do_sync_write,
1508        .aio_write = tun_chr_aio_write,
1509        .poll   = tun_chr_poll,
1510        .unlocked_ioctl = tun_chr_ioctl,
1511#ifdef CONFIG_COMPAT
1512        .compat_ioctl = tun_chr_compat_ioctl,
1513#endif
1514        .open   = tun_chr_open,
1515        .release = tun_chr_close,
1516        .fasync = tun_chr_fasync
1517};
1518
1519static struct miscdevice tun_miscdev = {
1520        .minor = TUN_MINOR,
1521        .name = "tun",
1522        .nodename = "net/tun",
1523        .fops = &tun_fops,
1524};
1525
1526/* ethtool interface */
1527
1528static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1529{
1530        cmd->supported          = 0;
1531        cmd->advertising        = 0;
1532        cmd->speed              = SPEED_10;
1533        cmd->duplex             = DUPLEX_FULL;
1534        cmd->port               = PORT_TP;
1535        cmd->phy_address        = 0;
1536        cmd->transceiver        = XCVR_INTERNAL;
1537        cmd->autoneg            = AUTONEG_DISABLE;
1538        cmd->maxtxpkt           = 0;
1539        cmd->maxrxpkt           = 0;
1540        return 0;
1541}
1542
1543static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1544{
1545        struct tun_struct *tun = netdev_priv(dev);
1546
1547        strcpy(info->driver, DRV_NAME);
1548        strcpy(info->version, DRV_VERSION);
1549        strcpy(info->fw_version, "N/A");
1550
1551        switch (tun->flags & TUN_TYPE_MASK) {
1552        case TUN_TUN_DEV:
1553                strcpy(info->bus_info, "tun");
1554                break;
1555        case TUN_TAP_DEV:
1556                strcpy(info->bus_info, "tap");
1557                break;
1558        }
1559}
1560
1561static u32 tun_get_msglevel(struct net_device *dev)
1562{
1563#ifdef TUN_DEBUG
1564        struct tun_struct *tun = netdev_priv(dev);
1565        return tun->debug;
1566#else
1567        return -EOPNOTSUPP;
1568#endif
1569}
1570
1571static void tun_set_msglevel(struct net_device *dev, u32 value)
1572{
1573#ifdef TUN_DEBUG
1574        struct tun_struct *tun = netdev_priv(dev);
1575        tun->debug = value;
1576#endif
1577}
1578
1579static u32 tun_get_rx_csum(struct net_device *dev)
1580{
1581        struct tun_struct *tun = netdev_priv(dev);
1582        return (tun->flags & TUN_NOCHECKSUM) == 0;
1583}
1584
1585static int tun_set_rx_csum(struct net_device *dev, u32 data)
1586{
1587        struct tun_struct *tun = netdev_priv(dev);
1588        if (data)
1589                tun->flags &= ~TUN_NOCHECKSUM;
1590        else
1591                tun->flags |= TUN_NOCHECKSUM;
1592        return 0;
1593}
1594
1595static const struct ethtool_ops tun_ethtool_ops = {
1596        .get_settings   = tun_get_settings,
1597        .get_drvinfo    = tun_get_drvinfo,
1598        .get_msglevel   = tun_get_msglevel,
1599        .set_msglevel   = tun_set_msglevel,
1600        .get_link       = ethtool_op_get_link,
1601        .get_rx_csum    = tun_get_rx_csum,
1602        .set_rx_csum    = tun_set_rx_csum
1603};
1604
1605
1606static int __init tun_init(void)
1607{
1608        int ret = 0;
1609
1610        printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1611        printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
1612
1613        ret = rtnl_link_register(&tun_link_ops);
1614        if (ret) {
1615                printk(KERN_ERR "tun: Can't register link_ops\n");
1616                goto err_linkops;
1617        }
1618
1619        ret = misc_register(&tun_miscdev);
1620        if (ret) {
1621                printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
1622                goto err_misc;
1623        }
1624        return  0;
1625err_misc:
1626        rtnl_link_unregister(&tun_link_ops);
1627err_linkops:
1628        return ret;
1629}
1630
1631static void tun_cleanup(void)
1632{
1633        misc_deregister(&tun_miscdev);
1634        rtnl_link_unregister(&tun_link_ops);
1635}
1636
1637/* Get an underlying socket object from tun file.  Returns error unless file is
1638 * attached to a device.  The returned object works like a packet socket, it
1639 * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
1640 * holding a reference to the file for as long as the socket is in use. */
1641struct socket *tun_get_socket(struct file *file)
1642{
1643        struct tun_struct *tun;
1644        if (file->f_op != &tun_fops)
1645                return ERR_PTR(-EINVAL);
1646        tun = tun_get(file);
1647        if (!tun)
1648                return ERR_PTR(-EBADFD);
1649        tun_put(tun);
1650        return &tun->socket;
1651}
1652EXPORT_SYMBOL_GPL(tun_get_socket);
1653
1654module_init(tun_init);
1655module_exit(tun_cleanup);
1656MODULE_DESCRIPTION(DRV_DESCRIPTION);
1657MODULE_AUTHOR(DRV_COPYRIGHT);
1658MODULE_LICENSE("GPL");
1659MODULE_ALIAS_MISCDEV(TUN_MINOR);
1660MODULE_ALIAS("devname:net/tun");
1661
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