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 eth_random_addr() for tap MAC address.
  26 *
  27 *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
  28 *    Fixes in packet dropping, queue length setting and queue wakeup.
  29 *    Increased default tx queue length.
  30 *    Added ethtool API.
  31 *    Minor cleanups
  32 *
  33 *  Daniel Podlejski <underley@underley.eu.org>
  34 *    Modifications for 2.3.99-pre5 kernel.
  35 */
  36
  37#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  38
  39#define DRV_NAME        "tun"
  40#define DRV_VERSION     "1.6"
  41#define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  42#define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
  43
  44#include <linux/module.h>
  45#include <linux/errno.h>
  46#include <linux/kernel.h>
  47#include <linux/major.h>
  48#include <linux/slab.h>
  49#include <linux/poll.h>
  50#include <linux/fcntl.h>
  51#include <linux/init.h>
  52#include <linux/skbuff.h>
  53#include <linux/netdevice.h>
  54#include <linux/etherdevice.h>
  55#include <linux/miscdevice.h>
  56#include <linux/ethtool.h>
  57#include <linux/rtnetlink.h>
  58#include <linux/compat.h>
  59#include <linux/if.h>
  60#include <linux/if_arp.h>
  61#include <linux/if_ether.h>
  62#include <linux/if_tun.h>
  63#include <linux/crc32.h>
  64#include <linux/nsproxy.h>
  65#include <linux/virtio_net.h>
  66#include <linux/rcupdate.h>
  67#include <net/net_namespace.h>
  68#include <net/netns/generic.h>
  69#include <net/rtnetlink.h>
  70#include <net/sock.h>
  71
  72#include <asm/uaccess.h>
  73
  74/* Uncomment to enable debugging */
  75/* #define TUN_DEBUG 1 */
  76
  77#ifdef TUN_DEBUG
  78static int debug;
  79
  80#define tun_debug(level, tun, fmt, args...)                     \
  81do {                                                            \
  82        if (tun->debug)                                         \
  83                netdev_printk(level, tun->dev, fmt, ##args);    \
  84} while (0)
  85#define DBG1(level, fmt, args...)                               \
  86do {                                                            \
  87        if (debug == 2)                                         \
  88                printk(level fmt, ##args);                      \
  89} while (0)
  90#else
  91#define tun_debug(level, tun, fmt, args...)                     \
  92do {                                                            \
  93        if (0)                                                  \
  94                netdev_printk(level, tun->dev, fmt, ##args);    \
  95} while (0)
  96#define DBG1(level, fmt, args...)                               \
  97do {                                                            \
  98        if (0)                                                  \
  99                printk(level fmt, ##args);                      \
 100} while (0)
 101#endif
 102
 103#define GOODCOPY_LEN 128
 104
 105#define FLT_EXACT_COUNT 8
 106struct tap_filter {
 107        unsigned int    count;    /* Number of addrs. Zero means disabled */
 108        u32             mask[2];  /* Mask of the hashed addrs */
 109        unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 110};
 111
 112struct tun_file {
 113        atomic_t count;
 114        struct tun_struct *tun;
 115        struct net *net;
 116};
 117
 118struct tun_sock;
 119
 120struct tun_struct {
 121        struct tun_file         *tfile;
 122        unsigned int            flags;
 123        uid_t                   owner;
 124        gid_t                   group;
 125
 126        struct net_device       *dev;
 127        netdev_features_t       set_features;
 128#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 129                          NETIF_F_TSO6|NETIF_F_UFO)
 130        struct fasync_struct    *fasync;
 131
 132        struct tap_filter       txflt;
 133        struct socket           socket;
 134        struct socket_wq        wq;
 135
 136        int                     vnet_hdr_sz;
 137
 138#ifdef TUN_DEBUG
 139        int debug;
 140#endif
 141};
 142
 143struct tun_sock {
 144        struct sock             sk;
 145        struct tun_struct       *tun;
 146};
 147
 148static inline struct tun_sock *tun_sk(struct sock *sk)
 149{
 150        return container_of(sk, struct tun_sock, sk);
 151}
 152
 153static int tun_attach(struct tun_struct *tun, struct file *file)
 154{
 155        struct tun_file *tfile = file->private_data;
 156        int err;
 157
 158        ASSERT_RTNL();
 159
 160        netif_tx_lock_bh(tun->dev);
 161
 162        err = -EINVAL;
 163        if (tfile->tun)
 164                goto out;
 165
 166        err = -EBUSY;
 167        if (tun->tfile)
 168                goto out;
 169
 170        err = 0;
 171        tfile->tun = tun;
 172        tun->tfile = tfile;
 173        tun->socket.file = file;
 174        netif_carrier_on(tun->dev);
 175        dev_hold(tun->dev);
 176        sock_hold(tun->socket.sk);
 177        atomic_inc(&tfile->count);
 178
 179out:
 180        netif_tx_unlock_bh(tun->dev);
 181        return err;
 182}
 183
 184static void __tun_detach(struct tun_struct *tun)
 185{
 186        /* Detach from net device */
 187        netif_tx_lock_bh(tun->dev);
 188        netif_carrier_off(tun->dev);
 189        tun->tfile = NULL;
 190        netif_tx_unlock_bh(tun->dev);
 191
 192        /* Drop read queue */
 193        skb_queue_purge(&tun->socket.sk->sk_receive_queue);
 194
 195        /* Drop the extra count on the net device */
 196        dev_put(tun->dev);
 197}
 198
 199static void tun_detach(struct tun_struct *tun)
 200{
 201        rtnl_lock();
 202        __tun_detach(tun);
 203        rtnl_unlock();
 204}
 205
 206static struct tun_struct *__tun_get(struct tun_file *tfile)
 207{
 208        struct tun_struct *tun = NULL;
 209
 210        if (atomic_inc_not_zero(&tfile->count))
 211                tun = tfile->tun;
 212
 213        return tun;
 214}
 215
 216static struct tun_struct *tun_get(struct file *file)
 217{
 218        return __tun_get(file->private_data);
 219}
 220
 221static void tun_put(struct tun_struct *tun)
 222{
 223        struct tun_file *tfile = tun->tfile;
 224
 225        if (atomic_dec_and_test(&tfile->count))
 226                tun_detach(tfile->tun);
 227}
 228
 229/* TAP filtering */
 230static void addr_hash_set(u32 *mask, const u8 *addr)
 231{
 232        int n = ether_crc(ETH_ALEN, addr) >> 26;
 233        mask[n >> 5] |= (1 << (n & 31));
 234}
 235
 236static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 237{
 238        int n = ether_crc(ETH_ALEN, addr) >> 26;
 239        return mask[n >> 5] & (1 << (n & 31));
 240}
 241
 242static int update_filter(struct tap_filter *filter, void __user *arg)
 243{
 244        struct { u8 u[ETH_ALEN]; } *addr;
 245        struct tun_filter uf;
 246        int err, alen, n, nexact;
 247
 248        if (copy_from_user(&uf, arg, sizeof(uf)))
 249                return -EFAULT;
 250
 251        if (!uf.count) {
 252                /* Disabled */
 253                filter->count = 0;
 254                return 0;
 255        }
 256
 257        alen = ETH_ALEN * uf.count;
 258        addr = kmalloc(alen, GFP_KERNEL);
 259        if (!addr)
 260                return -ENOMEM;
 261
 262        if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 263                err = -EFAULT;
 264                goto done;
 265        }
 266
 267        /* The filter is updated without holding any locks. Which is
 268         * perfectly safe. We disable it first and in the worst
 269         * case we'll accept a few undesired packets. */
 270        filter->count = 0;
 271        wmb();
 272
 273        /* Use first set of addresses as an exact filter */
 274        for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 275                memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 276
 277        nexact = n;
 278
 279        /* Remaining multicast addresses are hashed,
 280         * unicast will leave the filter disabled. */
 281        memset(filter->mask, 0, sizeof(filter->mask));
 282        for (; n < uf.count; n++) {
 283                if (!is_multicast_ether_addr(addr[n].u)) {
 284                        err = 0; /* no filter */
 285                        goto done;
 286                }
 287                addr_hash_set(filter->mask, addr[n].u);
 288        }
 289
 290        /* For ALLMULTI just set the mask to all ones.
 291         * This overrides the mask populated above. */
 292        if ((uf.flags & TUN_FLT_ALLMULTI))
 293                memset(filter->mask, ~0, sizeof(filter->mask));
 294
 295        /* Now enable the filter */
 296        wmb();
 297        filter->count = nexact;
 298
 299        /* Return the number of exact filters */
 300        err = nexact;
 301
 302done:
 303        kfree(addr);
 304        return err;
 305}
 306
 307/* Returns: 0 - drop, !=0 - accept */
 308static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 309{
 310        /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 311         * at this point. */
 312        struct ethhdr *eh = (struct ethhdr *) skb->data;
 313        int i;
 314
 315        /* Exact match */
 316        for (i = 0; i < filter->count; i++)
 317                if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 318                        return 1;
 319
 320        /* Inexact match (multicast only) */
 321        if (is_multicast_ether_addr(eh->h_dest))
 322                return addr_hash_test(filter->mask, eh->h_dest);
 323
 324        return 0;
 325}
 326
 327/*
 328 * Checks whether the packet is accepted or not.
 329 * Returns: 0 - drop, !=0 - accept
 330 */
 331static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 332{
 333        if (!filter->count)
 334                return 1;
 335
 336        return run_filter(filter, skb);
 337}
 338
 339/* Network device part of the driver */
 340
 341static const struct ethtool_ops tun_ethtool_ops;
 342
 343/* Net device detach from fd. */
 344static void tun_net_uninit(struct net_device *dev)
 345{
 346        struct tun_struct *tun = netdev_priv(dev);
 347        struct tun_file *tfile = tun->tfile;
 348
 349        /* Inform the methods they need to stop using the dev.
 350         */
 351        if (tfile) {
 352                wake_up_all(&tun->wq.wait);
 353                if (atomic_dec_and_test(&tfile->count))
 354                        __tun_detach(tun);
 355        }
 356}
 357
 358static void tun_free_netdev(struct net_device *dev)
 359{
 360        struct tun_struct *tun = netdev_priv(dev);
 361
 362        BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags));
 363
 364        sk_release_kernel(tun->socket.sk);
 365}
 366
 367/* Net device open. */
 368static int tun_net_open(struct net_device *dev)
 369{
 370        netif_start_queue(dev);
 371        return 0;
 372}
 373
 374/* Net device close. */
 375static int tun_net_close(struct net_device *dev)
 376{
 377        netif_stop_queue(dev);
 378        return 0;
 379}
 380
 381/* Net device start xmit */
 382static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 383{
 384        struct tun_struct *tun = netdev_priv(dev);
 385
 386        tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 387
 388        /* Drop packet if interface is not attached */
 389        if (!tun->tfile)
 390                goto drop;
 391
 392        /* Drop if the filter does not like it.
 393         * This is a noop if the filter is disabled.
 394         * Filter can be enabled only for the TAP devices. */
 395        if (!check_filter(&tun->txflt, skb))
 396                goto drop;
 397
 398        if (tun->socket.sk->sk_filter &&
 399            sk_filter(tun->socket.sk, skb))
 400                goto drop;
 401
 402        if (skb_queue_len(&tun->socket.sk->sk_receive_queue) >= dev->tx_queue_len) {
 403                if (!(tun->flags & TUN_ONE_QUEUE)) {
 404                        /* Normal queueing mode. */
 405                        /* Packet scheduler handles dropping of further packets. */
 406                        netif_stop_queue(dev);
 407
 408                        /* We won't see all dropped packets individually, so overrun
 409                         * error is more appropriate. */
 410                        dev->stats.tx_fifo_errors++;
 411                } else {
 412                        /* Single queue mode.
 413                         * Driver handles dropping of all packets itself. */
 414                        goto drop;
 415                }
 416        }
 417
 418        /* Orphan the skb - required as we might hang on to it
 419         * for indefinite time. */
 420        if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 421                goto drop;
 422        skb_orphan(skb);
 423
 424        /* Enqueue packet */
 425        skb_queue_tail(&tun->socket.sk->sk_receive_queue, skb);
 426
 427        /* Notify and wake up reader process */
 428        if (tun->flags & TUN_FASYNC)
 429                kill_fasync(&tun->fasync, SIGIO, POLL_IN);
 430        wake_up_interruptible_poll(&tun->wq.wait, POLLIN |
 431                                   POLLRDNORM | POLLRDBAND);
 432        return NETDEV_TX_OK;
 433
 434drop:
 435        dev->stats.tx_dropped++;
 436        kfree_skb(skb);
 437        return NETDEV_TX_OK;
 438}
 439
 440static void tun_net_mclist(struct net_device *dev)
 441{
 442        /*
 443         * This callback is supposed to deal with mc filter in
 444         * _rx_ path and has nothing to do with the _tx_ path.
 445         * In rx path we always accept everything userspace gives us.
 446         */
 447}
 448
 449#define MIN_MTU 68
 450#define MAX_MTU 65535
 451
 452static int
 453tun_net_change_mtu(struct net_device *dev, int new_mtu)
 454{
 455        if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 456                return -EINVAL;
 457        dev->mtu = new_mtu;
 458        return 0;
 459}
 460
 461static netdev_features_t tun_net_fix_features(struct net_device *dev,
 462        netdev_features_t features)
 463{
 464        struct tun_struct *tun = netdev_priv(dev);
 465
 466        return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 467}
 468#ifdef CONFIG_NET_POLL_CONTROLLER
 469static void tun_poll_controller(struct net_device *dev)
 470{
 471        /*
 472         * Tun only receives frames when:
 473         * 1) the char device endpoint gets data from user space
 474         * 2) the tun socket gets a sendmsg call from user space
 475         * Since both of those are syncronous operations, we are guaranteed
 476         * never to have pending data when we poll for it
 477         * so theres nothing to do here but return.
 478         * We need this though so netpoll recognizes us as an interface that
 479         * supports polling, which enables bridge devices in virt setups to
 480         * still use netconsole
 481         */
 482        return;
 483}
 484#endif
 485static const struct net_device_ops tun_netdev_ops = {
 486        .ndo_uninit             = tun_net_uninit,
 487        .ndo_open               = tun_net_open,
 488        .ndo_stop               = tun_net_close,
 489        .ndo_start_xmit         = tun_net_xmit,
 490        .ndo_change_mtu         = tun_net_change_mtu,
 491        .ndo_fix_features       = tun_net_fix_features,
 492#ifdef CONFIG_NET_POLL_CONTROLLER
 493        .ndo_poll_controller    = tun_poll_controller,
 494#endif
 495};
 496
 497static const struct net_device_ops tap_netdev_ops = {
 498        .ndo_uninit             = tun_net_uninit,
 499        .ndo_open               = tun_net_open,
 500        .ndo_stop               = tun_net_close,
 501        .ndo_start_xmit         = tun_net_xmit,
 502        .ndo_change_mtu         = tun_net_change_mtu,
 503        .ndo_fix_features       = tun_net_fix_features,
 504        .ndo_set_rx_mode        = tun_net_mclist,
 505        .ndo_set_mac_address    = eth_mac_addr,
 506        .ndo_validate_addr      = eth_validate_addr,
 507#ifdef CONFIG_NET_POLL_CONTROLLER
 508        .ndo_poll_controller    = tun_poll_controller,
 509#endif
 510};
 511
 512/* Initialize net device. */
 513static void tun_net_init(struct net_device *dev)
 514{
 515        struct tun_struct *tun = netdev_priv(dev);
 516
 517        switch (tun->flags & TUN_TYPE_MASK) {
 518        case TUN_TUN_DEV:
 519                dev->netdev_ops = &tun_netdev_ops;
 520
 521                /* Point-to-Point TUN Device */
 522                dev->hard_header_len = 0;
 523                dev->addr_len = 0;
 524                dev->mtu = 1500;
 525
 526                /* Zero header length */
 527                dev->type = ARPHRD_NONE;
 528                dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 529                dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 530                break;
 531
 532        case TUN_TAP_DEV:
 533                dev->netdev_ops = &tap_netdev_ops;
 534                /* Ethernet TAP Device */
 535                ether_setup(dev);
 536                dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 537
 538                eth_hw_addr_random(dev);
 539
 540                dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 541                break;
 542        }
 543}
 544
 545/* Character device part */
 546
 547/* Poll */
 548static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
 549{
 550        struct tun_file *tfile = file->private_data;
 551        struct tun_struct *tun = __tun_get(tfile);
 552        struct sock *sk;
 553        unsigned int mask = 0;
 554
 555        if (!tun)
 556                return POLLERR;
 557
 558        sk = tun->socket.sk;
 559
 560        tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
 561
 562        poll_wait(file, &tun->wq.wait, wait);
 563
 564        if (!skb_queue_empty(&sk->sk_receive_queue))
 565                mask |= POLLIN | POLLRDNORM;
 566
 567        if (sock_writeable(sk) ||
 568            (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 569             sock_writeable(sk)))
 570                mask |= POLLOUT | POLLWRNORM;
 571
 572        if (tun->dev->reg_state != NETREG_REGISTERED)
 573                mask = POLLERR;
 574
 575        tun_put(tun);
 576        return mask;
 577}
 578
 579/* prepad is the amount to reserve at front.  len is length after that.
 580 * linear is a hint as to how much to copy (usually headers). */
 581static struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
 582                                     size_t prepad, size_t len,
 583                                     size_t linear, int noblock)
 584{
 585        struct sock *sk = tun->socket.sk;
 586        struct sk_buff *skb;
 587        int err;
 588
 589        sock_update_classid(sk);
 590
 591        /* Under a page?  Don't bother with paged skb. */
 592        if (prepad + len < PAGE_SIZE || !linear)
 593                linear = len;
 594
 595        skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 596                                   &err);
 597        if (!skb)
 598                return ERR_PTR(err);
 599
 600        skb_reserve(skb, prepad);
 601        skb_put(skb, linear);
 602        skb->data_len = len - linear;
 603        skb->len += len - linear;
 604
 605        return skb;
 606}
 607
 608/* set skb frags from iovec, this can move to core network code for reuse */
 609static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
 610                                  int offset, size_t count)
 611{
 612        int len = iov_length(from, count) - offset;
 613        int copy = skb_headlen(skb);
 614        int size, offset1 = 0;
 615        int i = 0;
 616
 617        /* Skip over from offset */
 618        while (count && (offset >= from->iov_len)) {
 619                offset -= from->iov_len;
 620                ++from;
 621                --count;
 622        }
 623
 624        /* copy up to skb headlen */
 625        while (count && (copy > 0)) {
 626                size = min_t(unsigned int, copy, from->iov_len - offset);
 627                if (copy_from_user(skb->data + offset1, from->iov_base + offset,
 628                                   size))
 629                        return -EFAULT;
 630                if (copy > size) {
 631                        ++from;
 632                        --count;
 633                        offset = 0;
 634                } else
 635                        offset += size;
 636                copy -= size;
 637                offset1 += size;
 638        }
 639
 640        if (len == offset1)
 641                return 0;
 642
 643        while (count--) {
 644                struct page *page[MAX_SKB_FRAGS];
 645                int num_pages;
 646                unsigned long base;
 647                unsigned long truesize;
 648
 649                len = from->iov_len - offset;
 650                if (!len) {
 651                        offset = 0;
 652                        ++from;
 653                        continue;
 654                }
 655                base = (unsigned long)from->iov_base + offset;
 656                size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
 657                if (i + size > MAX_SKB_FRAGS)
 658                        return -EMSGSIZE;
 659                num_pages = get_user_pages_fast(base, size, 0, &page[i]);
 660                if (num_pages != size) {
 661                        for (i = 0; i < num_pages; i++)
 662                                put_page(page[i]);
 663                        return -EFAULT;
 664                }
 665                truesize = size * PAGE_SIZE;
 666                skb->data_len += len;
 667                skb->len += len;
 668                skb->truesize += truesize;
 669                atomic_add(truesize, &skb->sk->sk_wmem_alloc);
 670                while (len) {
 671                        int off = base & ~PAGE_MASK;
 672                        int size = min_t(int, len, PAGE_SIZE - off);
 673                        __skb_fill_page_desc(skb, i, page[i], off, size);
 674                        skb_shinfo(skb)->nr_frags++;
 675                        /* increase sk_wmem_alloc */
 676                        base += size;
 677                        len -= size;
 678                        i++;
 679                }
 680                offset = 0;
 681                ++from;
 682        }
 683        return 0;
 684}
 685
 686/* Get packet from user space buffer */
 687static ssize_t tun_get_user(struct tun_struct *tun, void *msg_control,
 688                            const struct iovec *iv, size_t total_len,
 689                            size_t count, int noblock)
 690{
 691        struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
 692        struct sk_buff *skb;
 693        size_t len = total_len, align = NET_SKB_PAD;
 694        struct virtio_net_hdr gso = { 0 };
 695        int offset = 0;
 696        int copylen;
 697        bool zerocopy = false;
 698        int err;
 699
 700        if (!(tun->flags & TUN_NO_PI)) {
 701                if ((len -= sizeof(pi)) > total_len)
 702                        return -EINVAL;
 703
 704                if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
 705                        return -EFAULT;
 706                offset += sizeof(pi);
 707        }
 708
 709        if (tun->flags & TUN_VNET_HDR) {
 710                if ((len -= tun->vnet_hdr_sz) > total_len)
 711                        return -EINVAL;
 712
 713                if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
 714                        return -EFAULT;
 715
 716                if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
 717                    gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
 718                        gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
 719
 720                if (gso.hdr_len > len)
 721                        return -EINVAL;
 722                offset += tun->vnet_hdr_sz;
 723        }
 724
 725        if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
 726                align += NET_IP_ALIGN;
 727                if (unlikely(len < ETH_HLEN ||
 728                             (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
 729                        return -EINVAL;
 730        }
 731
 732        if (msg_control)
 733                zerocopy = true;
 734
 735        if (zerocopy) {
 736                /* Userspace may produce vectors with count greater than
 737                 * MAX_SKB_FRAGS, so we need to linearize parts of the skb
 738                 * to let the rest of data to be fit in the frags.
 739                 */
 740                if (count > MAX_SKB_FRAGS) {
 741                        copylen = iov_length(iv, count - MAX_SKB_FRAGS);
 742                        if (copylen < offset)
 743                                copylen = 0;
 744                        else
 745                                copylen -= offset;
 746                } else
 747                                copylen = 0;
 748                /* There are 256 bytes to be copied in skb, so there is enough
 749                 * room for skb expand head in case it is used.
 750                 * The rest of the buffer is mapped from userspace.
 751                 */
 752                if (copylen < gso.hdr_len)
 753                        copylen = gso.hdr_len;
 754                if (!copylen)
 755                        copylen = GOODCOPY_LEN;
 756        } else
 757                copylen = len;
 758
 759        skb = tun_alloc_skb(tun, align, copylen, gso.hdr_len, noblock);
 760        if (IS_ERR(skb)) {
 761                if (PTR_ERR(skb) != -EAGAIN)
 762                        tun->dev->stats.rx_dropped++;
 763                return PTR_ERR(skb);
 764        }
 765
 766        if (zerocopy)
 767                err = zerocopy_sg_from_iovec(skb, iv, offset, count);
 768        else
 769                err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
 770
 771        if (err) {
 772                tun->dev->stats.rx_dropped++;
 773                kfree_skb(skb);
 774                return -EFAULT;
 775        }
 776
 777        if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 778                if (!skb_partial_csum_set(skb, gso.csum_start,
 779                                          gso.csum_offset)) {
 780                        tun->dev->stats.rx_frame_errors++;
 781                        kfree_skb(skb);
 782                        return -EINVAL;
 783                }
 784        }
 785
 786        switch (tun->flags & TUN_TYPE_MASK) {
 787        case TUN_TUN_DEV:
 788                if (tun->flags & TUN_NO_PI) {
 789                        switch (skb->data[0] & 0xf0) {
 790                        case 0x40:
 791                                pi.proto = htons(ETH_P_IP);
 792                                break;
 793                        case 0x60:
 794                                pi.proto = htons(ETH_P_IPV6);
 795                                break;
 796                        default:
 797                                tun->dev->stats.rx_dropped++;
 798                                kfree_skb(skb);
 799                                return -EINVAL;
 800                        }
 801                }
 802
 803                skb_reset_mac_header(skb);
 804                skb->protocol = pi.proto;
 805                skb->dev = tun->dev;
 806                break;
 807        case TUN_TAP_DEV:
 808                skb->protocol = eth_type_trans(skb, tun->dev);
 809                break;
 810        }
 811
 812        if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 813                pr_debug("GSO!\n");
 814                switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 815                case VIRTIO_NET_HDR_GSO_TCPV4:
 816                        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 817                        break;
 818                case VIRTIO_NET_HDR_GSO_TCPV6:
 819                        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 820                        break;
 821                case VIRTIO_NET_HDR_GSO_UDP:
 822                        skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 823                        break;
 824                default:
 825                        tun->dev->stats.rx_frame_errors++;
 826                        kfree_skb(skb);
 827                        return -EINVAL;
 828                }
 829
 830                if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 831                        skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 832
 833                skb_shinfo(skb)->gso_size = gso.gso_size;
 834                if (skb_shinfo(skb)->gso_size == 0) {
 835                        tun->dev->stats.rx_frame_errors++;
 836                        kfree_skb(skb);
 837                        return -EINVAL;
 838                }
 839
 840                /* Header must be checked, and gso_segs computed. */
 841                skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 842                skb_shinfo(skb)->gso_segs = 0;
 843        }
 844
 845        /* copy skb_ubuf_info for callback when skb has no error */
 846        if (zerocopy) {
 847                skb_shinfo(skb)->destructor_arg = msg_control;
 848                skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
 849        }
 850
 851        netif_rx_ni(skb);
 852
 853        tun->dev->stats.rx_packets++;
 854        tun->dev->stats.rx_bytes += len;
 855
 856        return total_len;
 857}
 858
 859static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 860                              unsigned long count, loff_t pos)
 861{
 862        struct file *file = iocb->ki_filp;
 863        struct tun_struct *tun = tun_get(file);
 864        ssize_t result;
 865
 866        if (!tun)
 867                return -EBADFD;
 868
 869        tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
 870
 871        result = tun_get_user(tun, NULL, iv, iov_length(iv, count), count,
 872                              file->f_flags & O_NONBLOCK);
 873
 874        tun_put(tun);
 875        return result;
 876}
 877
 878/* Put packet to the user space buffer */
 879static ssize_t tun_put_user(struct tun_struct *tun,
 880                            struct sk_buff *skb,
 881                            const struct iovec *iv, int len)
 882{
 883        struct tun_pi pi = { 0, skb->protocol };
 884        ssize_t total = 0;
 885
 886        if (!(tun->flags & TUN_NO_PI)) {
 887                if ((len -= sizeof(pi)) < 0)
 888                        return -EINVAL;
 889
 890                if (len < skb->len) {
 891                        /* Packet will be striped */
 892                        pi.flags |= TUN_PKT_STRIP;
 893                }
 894
 895                if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
 896                        return -EFAULT;
 897                total += sizeof(pi);
 898        }
 899
 900        if (tun->flags & TUN_VNET_HDR) {
 901                struct virtio_net_hdr gso = { 0 }; /* no info leak */
 902                if ((len -= tun->vnet_hdr_sz) < 0)
 903                        return -EINVAL;
 904
 905                if (skb_is_gso(skb)) {
 906                        struct skb_shared_info *sinfo = skb_shinfo(skb);
 907
 908                        /* This is a hint as to how much should be linear. */
 909                        gso.hdr_len = skb_headlen(skb);
 910                        gso.gso_size = sinfo->gso_size;
 911                        if (sinfo->gso_type & SKB_GSO_TCPV4)
 912                                gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 913                        else if (sinfo->gso_type & SKB_GSO_TCPV6)
 914                                gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 915                        else if (sinfo->gso_type & SKB_GSO_UDP)
 916                                gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 917                        else {
 918                                pr_err("unexpected GSO type: "
 919                                       "0x%x, gso_size %d, hdr_len %d\n",
 920                                       sinfo->gso_type, gso.gso_size,
 921                                       gso.hdr_len);
 922                                print_hex_dump(KERN_ERR, "tun: ",
 923                                               DUMP_PREFIX_NONE,
 924                                               16, 1, skb->head,
 925                                               min((int)gso.hdr_len, 64), true);
 926                                WARN_ON_ONCE(1);
 927                                return -EINVAL;
 928                        }
 929                        if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 930                                gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 931                } else
 932                        gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 933
 934                if (skb->ip_summed == CHECKSUM_PARTIAL) {
 935                        gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 936                        gso.csum_start = skb_checksum_start_offset(skb);
 937                        gso.csum_offset = skb->csum_offset;
 938                } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
 939                        gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
 940                } /* else everything is zero */
 941
 942                if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
 943                                               sizeof(gso))))
 944                        return -EFAULT;
 945                total += tun->vnet_hdr_sz;
 946        }
 947
 948        len = min_t(int, skb->len, len);
 949
 950        skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
 951        total += skb->len;
 952
 953        tun->dev->stats.tx_packets++;
 954        tun->dev->stats.tx_bytes += len;
 955
 956        return total;
 957}
 958
 959static ssize_t tun_do_read(struct tun_struct *tun,
 960                           struct kiocb *iocb, const struct iovec *iv,
 961                           ssize_t len, int noblock)
 962{
 963        DECLARE_WAITQUEUE(wait, current);
 964        struct sk_buff *skb;
 965        ssize_t ret = 0;
 966
 967        tun_debug(KERN_INFO, tun, "tun_chr_read\n");
 968
 969        if (unlikely(!noblock))
 970                add_wait_queue(&tun->wq.wait, &wait);
 971        while (len) {
 972                current->state = TASK_INTERRUPTIBLE;
 973
 974                /* Read frames from the queue */
 975                if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) {
 976                        if (noblock) {
 977                                ret = -EAGAIN;
 978                                break;
 979                        }
 980                        if (signal_pending(current)) {
 981                                ret = -ERESTARTSYS;
 982                                break;
 983                        }
 984                        if (tun->dev->reg_state != NETREG_REGISTERED) {
 985                                ret = -EIO;
 986                                break;
 987                        }
 988
 989                        /* Nothing to read, let's sleep */
 990                        schedule();
 991                        continue;
 992                }
 993                netif_wake_queue(tun->dev);
 994
 995                ret = tun_put_user(tun, skb, iv, len);
 996                kfree_skb(skb);
 997                break;
 998        }
 999
1000        current->state = TASK_RUNNING;
1001        if (unlikely(!noblock))
1002                remove_wait_queue(&tun->wq.wait, &wait);
1003
1004        return ret;
1005}
1006
1007static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1008                            unsigned long count, loff_t pos)
1009{
1010        struct file *file = iocb->ki_filp;
1011        struct tun_file *tfile = file->private_data;
1012        struct tun_struct *tun = __tun_get(tfile);
1013        ssize_t len, ret;
1014
1015        if (!tun)
1016                return -EBADFD;
1017        len = iov_length(iv, count);
1018        if (len < 0) {
1019                ret = -EINVAL;
1020                goto out;
1021        }
1022
1023        ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK);
1024        ret = min_t(ssize_t, ret, len);
1025out:
1026        tun_put(tun);
1027        return ret;
1028}
1029
1030static void tun_setup(struct net_device *dev)
1031{
1032        struct tun_struct *tun = netdev_priv(dev);
1033
1034        tun->owner = -1;
1035        tun->group = -1;
1036
1037        dev->ethtool_ops = &tun_ethtool_ops;
1038        dev->destructor = tun_free_netdev;
1039}
1040
1041/* Trivial set of netlink ops to allow deleting tun or tap
1042 * device with netlink.
1043 */
1044static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1045{
1046        return -EINVAL;
1047}
1048
1049static struct rtnl_link_ops tun_link_ops __read_mostly = {
1050        .kind           = DRV_NAME,
1051        .priv_size      = sizeof(struct tun_struct),
1052        .setup          = tun_setup,
1053        .validate       = tun_validate,
1054};
1055
1056static void tun_sock_write_space(struct sock *sk)
1057{
1058        struct tun_struct *tun;
1059        wait_queue_head_t *wqueue;
1060
1061        if (!sock_writeable(sk))
1062                return;
1063
1064        if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1065                return;
1066
1067        wqueue = sk_sleep(sk);
1068        if (wqueue && waitqueue_active(wqueue))
1069                wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1070                                                POLLWRNORM | POLLWRBAND);
1071
1072        tun = tun_sk(sk)->tun;
1073        kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
1074}
1075
1076static void tun_sock_destruct(struct sock *sk)
1077{
1078        free_netdev(tun_sk(sk)->tun->dev);
1079}
1080
1081static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1082                       struct msghdr *m, size_t total_len)
1083{
1084        struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
1085        return tun_get_user(tun, m->msg_control, m->msg_iov, total_len,
1086                            m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1087}
1088
1089static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1090                       struct msghdr *m, size_t total_len,
1091                       int flags)
1092{
1093        struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
1094        int ret;
1095        if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1096                return -EINVAL;
1097        ret = tun_do_read(tun, iocb, m->msg_iov, total_len,
1098                          flags & MSG_DONTWAIT);
1099        if (ret > total_len) {
1100                m->msg_flags |= MSG_TRUNC;
1101                ret = flags & MSG_TRUNC ? ret : total_len;
1102        }
1103        return ret;
1104}
1105
1106static int tun_release(struct socket *sock)
1107{
1108        if (sock->sk)
1109                sock_put(sock->sk);
1110        return 0;
1111}
1112
1113/* Ops structure to mimic raw sockets with tun */
1114static const struct proto_ops tun_socket_ops = {
1115        .sendmsg = tun_sendmsg,
1116        .recvmsg = tun_recvmsg,
1117        .release = tun_release,
1118};
1119
1120static struct proto tun_proto = {
1121        .name           = "tun",
1122        .owner          = THIS_MODULE,
1123        .obj_size       = sizeof(struct tun_sock),
1124};
1125
1126static int tun_flags(struct tun_struct *tun)
1127{
1128        int flags = 0;
1129
1130        if (tun->flags & TUN_TUN_DEV)
1131                flags |= IFF_TUN;
1132        else
1133                flags |= IFF_TAP;
1134
1135        if (tun->flags & TUN_NO_PI)
1136                flags |= IFF_NO_PI;
1137
1138        if (tun->flags & TUN_ONE_QUEUE)
1139                flags |= IFF_ONE_QUEUE;
1140
1141        if (tun->flags & TUN_VNET_HDR)
1142                flags |= IFF_VNET_HDR;
1143
1144        return flags;
1145}
1146
1147static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1148                              char *buf)
1149{
1150        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1151        return sprintf(buf, "0x%x\n", tun_flags(tun));
1152}
1153
1154static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1155                              char *buf)
1156{
1157        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1158        return sprintf(buf, "%d\n", tun->owner);
1159}
1160
1161static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1162                              char *buf)
1163{
1164        struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1165        return sprintf(buf, "%d\n", tun->group);
1166}
1167
1168static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1169static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1170static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1171
1172static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1173{
1174        struct sock *sk;
1175        struct tun_struct *tun;
1176        struct net_device *dev;
1177        int err;
1178
1179        dev = __dev_get_by_name(net, ifr->ifr_name);
1180        if (dev) {
1181                const struct cred *cred = current_cred();
1182
1183                if (ifr->ifr_flags & IFF_TUN_EXCL)
1184                        return -EBUSY;
1185                if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1186                        tun = netdev_priv(dev);
1187                else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1188                        tun = netdev_priv(dev);
1189                else
1190                        return -EINVAL;
1191
1192                if (((tun->owner != -1 && cred->euid != tun->owner) ||
1193                     (tun->group != -1 && !in_egroup_p(tun->group))) &&
1194                    !capable(CAP_NET_ADMIN))
1195                        return -EPERM;
1196                err = security_tun_dev_attach(tun->socket.sk);
1197                if (err < 0)
1198                        return err;
1199
1200                err = tun_attach(tun, file);
1201                if (err < 0)
1202                        return err;
1203        }
1204        else {
1205                char *name;
1206                unsigned long flags = 0;
1207
1208                if (!capable(CAP_NET_ADMIN))
1209                        return -EPERM;
1210                err = security_tun_dev_create();
1211                if (err < 0)
1212                        return err;
1213
1214                /* Set dev type */
1215                if (ifr->ifr_flags & IFF_TUN) {
1216                        /* TUN device */
1217                        flags |= TUN_TUN_DEV;
1218                        name = "tun%d";
1219                } else if (ifr->ifr_flags & IFF_TAP) {
1220                        /* TAP device */
1221                        flags |= TUN_TAP_DEV;
1222                        name = "tap%d";
1223                } else
1224                        return -EINVAL;
1225
1226                if (*ifr->ifr_name)
1227                        name = ifr->ifr_name;
1228
1229                dev = alloc_netdev(sizeof(struct tun_struct), name,
1230                                   tun_setup);
1231                if (!dev)
1232                        return -ENOMEM;
1233
1234                dev_net_set(dev, net);
1235                dev->rtnl_link_ops = &tun_link_ops;
1236
1237                tun = netdev_priv(dev);
1238                tun->dev = dev;
1239                tun->flags = flags;
1240                tun->txflt.count = 0;
1241                tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1242                set_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags);
1243
1244                err = -ENOMEM;
1245                sk = sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
1246                if (!sk)
1247                        goto err_free_dev;
1248
1249                sk_change_net(sk, net);
1250                tun->socket.wq = &tun->wq;
1251                init_waitqueue_head(&tun->wq.wait);
1252                tun->socket.ops = &tun_socket_ops;
1253                sock_init_data(&tun->socket, sk);
1254                sk->sk_write_space = tun_sock_write_space;
1255                sk->sk_sndbuf = INT_MAX;
1256                sock_set_flag(sk, SOCK_ZEROCOPY);
1257
1258                tun_sk(sk)->tun = tun;
1259
1260                security_tun_dev_post_create(sk);
1261
1262                tun_net_init(dev);
1263
1264                dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1265                        TUN_USER_FEATURES;
1266                dev->features = dev->hw_features;
1267
1268                err = register_netdevice(tun->dev);
1269                if (err < 0)
1270                        goto err_free_sk;
1271
1272                if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1273                    device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1274                    device_create_file(&tun->dev->dev, &dev_attr_group))
1275                        pr_err("Failed to create tun sysfs files\n");
1276
1277                sk->sk_destruct = tun_sock_destruct;
1278
1279                err = tun_attach(tun, file);
1280                if (err < 0)
1281                        goto failed;
1282        }
1283
1284        tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1285
1286        if (ifr->ifr_flags & IFF_NO_PI)
1287                tun->flags |= TUN_NO_PI;
1288        else
1289                tun->flags &= ~TUN_NO_PI;
1290
1291        if (ifr->ifr_flags & IFF_ONE_QUEUE)
1292                tun->flags |= TUN_ONE_QUEUE;
1293        else
1294                tun->flags &= ~TUN_ONE_QUEUE;
1295
1296        if (ifr->ifr_flags & IFF_VNET_HDR)
1297                tun->flags |= TUN_VNET_HDR;
1298        else
1299                tun->flags &= ~TUN_VNET_HDR;
1300
1301        /* Make sure persistent devices do not get stuck in
1302         * xoff state.
1303         */
1304        if (netif_running(tun->dev))
1305                netif_wake_queue(tun->dev);
1306
1307        strcpy(ifr->ifr_name, tun->dev->name);
1308        return 0;
1309
1310 err_free_sk:
1311        tun_free_netdev(dev);
1312 err_free_dev:
1313        free_netdev(dev);
1314 failed:
1315        return err;
1316}
1317
1318static int tun_get_iff(struct net *net, struct tun_struct *tun,
1319                       struct ifreq *ifr)
1320{
1321        tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1322
1323        strcpy(ifr->ifr_name, tun->dev->name);
1324
1325        ifr->ifr_flags = tun_flags(tun);
1326
1327        return 0;
1328}
1329
1330/* This is like a cut-down ethtool ops, except done via tun fd so no
1331 * privs required. */
1332static int set_offload(struct tun_struct *tun, unsigned long arg)
1333{
1334        netdev_features_t features = 0;
1335
1336        if (arg & TUN_F_CSUM) {
1337                features |= NETIF_F_HW_CSUM;
1338                arg &= ~TUN_F_CSUM;
1339
1340                if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1341                        if (arg & TUN_F_TSO_ECN) {
1342                                features |= NETIF_F_TSO_ECN;
1343                                arg &= ~TUN_F_TSO_ECN;
1344                        }
1345                        if (arg & TUN_F_TSO4)
1346                                features |= NETIF_F_TSO;
1347                        if (arg & TUN_F_TSO6)
1348                                features |= NETIF_F_TSO6;
1349                        arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1350                }
1351
1352                if (arg & TUN_F_UFO) {
1353                        features |= NETIF_F_UFO;
1354                        arg &= ~TUN_F_UFO;
1355                }
1356        }
1357
1358        /* This gives the user a way to test for new features in future by
1359         * trying to set them. */
1360        if (arg)
1361                return -EINVAL;
1362
1363        tun->set_features = features;
1364        netdev_update_features(tun->dev);
1365
1366        return 0;
1367}
1368
1369static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1370                            unsigned long arg, int ifreq_len)
1371{
1372        struct tun_file *tfile = file->private_data;
1373        struct tun_struct *tun;
1374        void __user* argp = (void __user*)arg;
1375        struct sock_fprog fprog;
1376        struct ifreq ifr;
1377        int sndbuf;
1378        int vnet_hdr_sz;
1379        int ret;
1380
1381        if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) {
1382                if (copy_from_user(&ifr, argp, ifreq_len))
1383                        return -EFAULT;
1384        } else {
1385                memset(&ifr, 0, sizeof(ifr));
1386        }
1387        if (cmd == TUNGETFEATURES) {
1388                /* Currently this just means: "what IFF flags are valid?".
1389                 * This is needed because we never checked for invalid flags on
1390                 * TUNSETIFF. */
1391                return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1392                                IFF_VNET_HDR,
1393                                (unsigned int __user*)argp);
1394        }
1395
1396        rtnl_lock();
1397
1398        tun = __tun_get(tfile);
1399        if (cmd == TUNSETIFF && !tun) {
1400                ifr.ifr_name[IFNAMSIZ-1] = '\0';
1401
1402                ret = tun_set_iff(tfile->net, file, &ifr);
1403
1404                if (ret)
1405                        goto unlock;
1406
1407                if (copy_to_user(argp, &ifr, ifreq_len))
1408                        ret = -EFAULT;
1409                goto unlock;
1410        }
1411
1412        ret = -EBADFD;
1413        if (!tun)
1414                goto unlock;
1415
1416        tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %d\n", cmd);
1417
1418        ret = 0;
1419        switch (cmd) {
1420        case TUNGETIFF:
1421                ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1422                if (ret)
1423                        break;
1424
1425                if (copy_to_user(argp, &ifr, ifreq_len))
1426                        ret = -EFAULT;
1427                break;
1428
1429        case TUNSETNOCSUM:
1430                /* Disable/Enable checksum */
1431
1432                /* [unimplemented] */
1433                tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1434                          arg ? "disabled" : "enabled");
1435                break;
1436
1437        case TUNSETPERSIST:
1438                /* Disable/Enable persist mode */
1439                if (arg)
1440                        tun->flags |= TUN_PERSIST;
1441                else
1442                        tun->flags &= ~TUN_PERSIST;
1443
1444                tun_debug(KERN_INFO, tun, "persist %s\n",
1445                          arg ? "enabled" : "disabled");
1446                break;
1447
1448        case TUNSETOWNER:
1449                /* Set owner of the device */
1450                tun->owner = (uid_t) arg;
1451
1452                tun_debug(KERN_INFO, tun, "owner set to %d\n", tun->owner);
1453                break;
1454
1455        case TUNSETGROUP:
1456                /* Set group of the device */
1457                tun->group= (gid_t) arg;
1458
1459                tun_debug(KERN_INFO, tun, "group set to %d\n", tun->group);
1460                break;
1461
1462        case TUNSETLINK:
1463                /* Only allow setting the type when the interface is down */
1464                if (tun->dev->flags & IFF_UP) {
1465                        tun_debug(KERN_INFO, tun,
1466                                  "Linktype set failed because interface is up\n");
1467                        ret = -EBUSY;
1468                } else {
1469                        tun->dev->type = (int) arg;
1470                        tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1471                                  tun->dev->type);
1472                        ret = 0;
1473                }
1474                break;
1475
1476#ifdef TUN_DEBUG
1477        case TUNSETDEBUG:
1478                tun->debug = arg;
1479                break;
1480#endif
1481        case TUNSETOFFLOAD:
1482                ret = set_offload(tun, arg);
1483                break;
1484
1485        case TUNSETTXFILTER:
1486                /* Can be set only for TAPs */
1487                ret = -EINVAL;
1488                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1489                        break;
1490                ret = update_filter(&tun->txflt, (void __user *)arg);
1491                break;
1492
1493        case SIOCGIFHWADDR:
1494                /* Get hw address */
1495                memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1496                ifr.ifr_hwaddr.sa_family = tun->dev->type;
1497                if (copy_to_user(argp, &ifr, ifreq_len))
1498                        ret = -EFAULT;
1499                break;
1500
1501        case SIOCSIFHWADDR:
1502                /* Set hw address */
1503                tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1504                          ifr.ifr_hwaddr.sa_data);
1505
1506                ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1507                break;
1508
1509        case TUNGETSNDBUF:
1510                sndbuf = tun->socket.sk->sk_sndbuf;
1511                if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1512                        ret = -EFAULT;
1513                break;
1514
1515        case TUNSETSNDBUF:
1516                if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1517                        ret = -EFAULT;
1518                        break;
1519                }
1520
1521                tun->socket.sk->sk_sndbuf = sndbuf;
1522                break;
1523
1524        case TUNGETVNETHDRSZ:
1525                vnet_hdr_sz = tun->vnet_hdr_sz;
1526                if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
1527                        ret = -EFAULT;
1528                break;
1529
1530        case TUNSETVNETHDRSZ:
1531                if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
1532                        ret = -EFAULT;
1533                        break;
1534                }
1535                if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
1536                        ret = -EINVAL;
1537                        break;
1538                }
1539
1540                tun->vnet_hdr_sz = vnet_hdr_sz;
1541                break;
1542
1543        case TUNATTACHFILTER:
1544                /* Can be set only for TAPs */
1545                ret = -EINVAL;
1546                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1547                        break;
1548                ret = -EFAULT;
1549                if (copy_from_user(&fprog, argp, sizeof(fprog)))
1550                        break;
1551
1552                ret = sk_attach_filter(&fprog, tun->socket.sk);
1553                break;
1554
1555        case TUNDETACHFILTER:
1556                /* Can be set only for TAPs */
1557                ret = -EINVAL;
1558                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1559                        break;
1560                ret = sk_detach_filter(tun->socket.sk);
1561                break;
1562
1563        default:
1564                ret = -EINVAL;
1565                break;
1566        }
1567
1568unlock:
1569        rtnl_unlock();
1570        if (tun)
1571                tun_put(tun);
1572        return ret;
1573}
1574
1575static long tun_chr_ioctl(struct file *file,
1576                          unsigned int cmd, unsigned long arg)
1577{
1578        return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
1579}
1580
1581#ifdef CONFIG_COMPAT
1582static long tun_chr_compat_ioctl(struct file *file,
1583                         unsigned int cmd, unsigned long arg)
1584{
1585        switch (cmd) {
1586        case TUNSETIFF:
1587        case TUNGETIFF:
1588        case TUNSETTXFILTER:
1589        case TUNGETSNDBUF:
1590        case TUNSETSNDBUF:
1591        case SIOCGIFHWADDR:
1592        case SIOCSIFHWADDR:
1593                arg = (unsigned long)compat_ptr(arg);
1594                break;
1595        default:
1596                arg = (compat_ulong_t)arg;
1597                break;
1598        }
1599
1600        /*
1601         * compat_ifreq is shorter than ifreq, so we must not access beyond
1602         * the end of that structure. All fields that are used in this
1603         * driver are compatible though, we don't need to convert the
1604         * contents.
1605         */
1606        return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
1607}
1608#endif /* CONFIG_COMPAT */
1609
1610static int tun_chr_fasync(int fd, struct file *file, int on)
1611{
1612        struct tun_struct *tun = tun_get(file);
1613        int ret;
1614
1615        if (!tun)
1616                return -EBADFD;
1617
1618        tun_debug(KERN_INFO, tun, "tun_chr_fasync %d\n", on);
1619
1620        if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1621                goto out;
1622
1623        if (on) {
1624                ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1625                if (ret)
1626                        goto out;
1627                tun->flags |= TUN_FASYNC;
1628        } else
1629                tun->flags &= ~TUN_FASYNC;
1630        ret = 0;
1631out:
1632        tun_put(tun);
1633        return ret;
1634}
1635
1636static int tun_chr_open(struct inode *inode, struct file * file)
1637{
1638        struct tun_file *tfile;
1639
1640        DBG1(KERN_INFO, "tunX: tun_chr_open\n");
1641
1642        tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1643        if (!tfile)
1644                return -ENOMEM;
1645        atomic_set(&tfile->count, 0);
1646        tfile->tun = NULL;
1647        tfile->net = get_net(current->nsproxy->net_ns);
1648        file->private_data = tfile;
1649        return 0;
1650}
1651
1652static int tun_chr_close(struct inode *inode, struct file *file)
1653{
1654        struct tun_file *tfile = file->private_data;
1655        struct tun_struct *tun;
1656
1657        tun = __tun_get(tfile);
1658        if (tun) {
1659                struct net_device *dev = tun->dev;
1660
1661                tun_debug(KERN_INFO, tun, "tun_chr_close\n");
1662
1663                __tun_detach(tun);
1664
1665                /* If desirable, unregister the netdevice. */
1666                if (!(tun->flags & TUN_PERSIST)) {
1667                        rtnl_lock();
1668                        if (dev->reg_state == NETREG_REGISTERED)
1669                                unregister_netdevice(dev);
1670                        rtnl_unlock();
1671                }
1672        }
1673
1674        tun = tfile->tun;
1675        if (tun)
1676                sock_put(tun->socket.sk);
1677
1678        put_net(tfile->net);
1679        kfree(tfile);
1680
1681        return 0;
1682}
1683
1684static const struct file_operations tun_fops = {
1685        .owner  = THIS_MODULE,
1686        .llseek = no_llseek,
1687        .read  = do_sync_read,
1688        .aio_read  = tun_chr_aio_read,
1689        .write = do_sync_write,
1690        .aio_write = tun_chr_aio_write,
1691        .poll   = tun_chr_poll,
1692        .unlocked_ioctl = tun_chr_ioctl,
1693#ifdef CONFIG_COMPAT
1694        .compat_ioctl = tun_chr_compat_ioctl,
1695#endif
1696        .open   = tun_chr_open,
1697        .release = tun_chr_close,
1698        .fasync = tun_chr_fasync
1699};
1700
1701static struct miscdevice tun_miscdev = {
1702        .minor = TUN_MINOR,
1703        .name = "tun",
1704        .nodename = "net/tun",
1705        .fops = &tun_fops,
1706};
1707
1708/* ethtool interface */
1709
1710static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1711{
1712        cmd->supported          = 0;
1713        cmd->advertising        = 0;
1714        ethtool_cmd_speed_set(cmd, SPEED_10);
1715        cmd->duplex             = DUPLEX_FULL;
1716        cmd->port               = PORT_TP;
1717        cmd->phy_address        = 0;
1718        cmd->transceiver        = XCVR_INTERNAL;
1719        cmd->autoneg            = AUTONEG_DISABLE;
1720        cmd->maxtxpkt           = 0;
1721        cmd->maxrxpkt           = 0;
1722        return 0;
1723}
1724
1725static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1726{
1727        struct tun_struct *tun = netdev_priv(dev);
1728
1729        strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
1730        strlcpy(info->version, DRV_VERSION, sizeof(info->version));
1731
1732        switch (tun->flags & TUN_TYPE_MASK) {
1733        case TUN_TUN_DEV:
1734                strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
1735                break;
1736        case TUN_TAP_DEV:
1737                strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
1738                break;
1739        }
1740}
1741
1742static u32 tun_get_msglevel(struct net_device *dev)
1743{
1744#ifdef TUN_DEBUG
1745        struct tun_struct *tun = netdev_priv(dev);
1746        return tun->debug;
1747#else
1748        return -EOPNOTSUPP;
1749#endif
1750}
1751
1752static void tun_set_msglevel(struct net_device *dev, u32 value)
1753{
1754#ifdef TUN_DEBUG
1755        struct tun_struct *tun = netdev_priv(dev);
1756        tun->debug = value;
1757#endif
1758}
1759
1760static const struct ethtool_ops tun_ethtool_ops = {
1761        .get_settings   = tun_get_settings,
1762        .get_drvinfo    = tun_get_drvinfo,
1763        .get_msglevel   = tun_get_msglevel,
1764        .set_msglevel   = tun_set_msglevel,
1765        .get_link       = ethtool_op_get_link,
1766};
1767
1768
1769static int __init tun_init(void)
1770{
1771        int ret = 0;
1772
1773        pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1774        pr_info("%s\n", DRV_COPYRIGHT);
1775
1776        ret = rtnl_link_register(&tun_link_ops);
1777        if (ret) {
1778                pr_err("Can't register link_ops\n");
1779                goto err_linkops;
1780        }
1781
1782        ret = misc_register(&tun_miscdev);
1783        if (ret) {
1784                pr_err("Can't register misc device %d\n", TUN_MINOR);
1785                goto err_misc;
1786        }
1787        return  0;
1788err_misc:
1789        rtnl_link_unregister(&tun_link_ops);
1790err_linkops:
1791        return ret;
1792}
1793
1794static void tun_cleanup(void)
1795{
1796        misc_deregister(&tun_miscdev);
1797        rtnl_link_unregister(&tun_link_ops);
1798}
1799
1800/* Get an underlying socket object from tun file.  Returns error unless file is
1801 * attached to a device.  The returned object works like a packet socket, it
1802 * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
1803 * holding a reference to the file for as long as the socket is in use. */
1804struct socket *tun_get_socket(struct file *file)
1805{
1806        struct tun_struct *tun;
1807        if (file->f_op != &tun_fops)
1808                return ERR_PTR(-EINVAL);
1809        tun = tun_get(file);
1810        if (!tun)
1811                return ERR_PTR(-EBADFD);
1812        tun_put(tun);
1813        return &tun->socket;
1814}
1815EXPORT_SYMBOL_GPL(tun_get_socket);
1816
1817module_init(tun_init);
1818module_exit(tun_cleanup);
1819MODULE_DESCRIPTION(DRV_DESCRIPTION);
1820MODULE_AUTHOR(DRV_COPYRIGHT);
1821MODULE_LICENSE("GPL");
1822MODULE_ALIAS_MISCDEV(TUN_MINOR);
1823MODULE_ALIAS("devname:net/tun");
1824
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