Pileus Git - ~andy/linux/blob - drivers/net/tun.c

   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 #include <net/cls_cgroup.h>
  72
  73 #include <asm/uaccess.h>
  74
  75 /* Uncomment to enable debugging */
  76 /* #define TUN_DEBUG 1 */
  77
  78 #ifdef TUN_DEBUG
  79 static int debug;
  80
  81 #define tun_debug(level, tun, fmt, args...)                     \
  82 do {                                                            \
  83         if (tun->debug)                                         \
  84                 netdev_printk(level, tun->dev, fmt, ##args);    \
  85 } while (0)
  86 #define DBG1(level, fmt, args...)                               \
  87 do {                                                            \
  88         if (debug == 2)                                         \
  89                 printk(level fmt, ##args);                      \
  90 } while (0)
  91 #else
  92 #define tun_debug(level, tun, fmt, args...)                     \
  93 do {                                                            \
  94         if (0)                                                  \
  95                 netdev_printk(level, tun->dev, fmt, ##args);    \
  96 } while (0)
  97 #define DBG1(level, fmt, args...)                               \
  98 do {                                                            \
  99         if (0)                                                  \
 100                 printk(level fmt, ##args);                      \
 101 } while (0)
 102 #endif
 103
 104 #define GOODCOPY_LEN 128
 105
 106 #define FLT_EXACT_COUNT 8
 107 struct tap_filter {
 108         unsigned int    count;    /* Number of addrs. Zero means disabled */
 109         u32             mask[2];  /* Mask of the hashed addrs */
 110         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 111 };
 112
 113 struct tun_file {
 114         atomic_t count;
 115         struct tun_struct *tun;
 116         struct net *net;
 117 };
 118
 119 struct tun_sock;
 120
 121 struct tun_struct {
 122         struct tun_file         *tfile;
 123         unsigned int            flags;
 124         kuid_t                  owner;
 125         kgid_t                  group;
 126
 127         struct net_device       *dev;
 128         netdev_features_t       set_features;
 129 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 130                           NETIF_F_TSO6|NETIF_F_UFO)
 131         struct fasync_struct    *fasync;
 132
 133         struct tap_filter       txflt;
 134         struct socket           socket;
 135         struct socket_wq        wq;
 136
 137         int                     vnet_hdr_sz;
 138
 139 #ifdef TUN_DEBUG
 140         int debug;
 141 #endif
 142 };
 143
 144 struct tun_sock {
 145         struct sock             sk;
 146         struct tun_struct       *tun;
 147 };
 148
 149 static inline struct tun_sock *tun_sk(struct sock *sk)
 150 {
 151         return container_of(sk, struct tun_sock, sk);
 152 }
 153
 154 static int tun_attach(struct tun_struct *tun, struct file *file)
 155 {
 156         struct tun_file *tfile = file->private_data;
 157         int err;
 158
 159         ASSERT_RTNL();
 160
 161         netif_tx_lock_bh(tun->dev);
 162
 163         err = -EINVAL;
 164         if (tfile->tun)
 165                 goto out;
 166
 167         err = -EBUSY;
 168         if (tun->tfile)
 169                 goto out;
 170
 171         err = 0;
 172         tfile->tun = tun;
 173         tun->tfile = tfile;
 174         tun->socket.file = file;
 175         netif_carrier_on(tun->dev);
 176         dev_hold(tun->dev);
 177         sock_hold(tun->socket.sk);
 178         atomic_inc(&tfile->count);
 179
 180 out:
 181         netif_tx_unlock_bh(tun->dev);
 182         return err;
 183 }
 184
 185 static void __tun_detach(struct tun_struct *tun)
 186 {
 187         /* Detach from net device */
 188         netif_tx_lock_bh(tun->dev);
 189         netif_carrier_off(tun->dev);
 190         tun->tfile = NULL;
 191         netif_tx_unlock_bh(tun->dev);
 192
 193         /* Drop read queue */
 194         skb_queue_purge(&tun->socket.sk->sk_receive_queue);
 195
 196         /* Drop the extra count on the net device */
 197         dev_put(tun->dev);
 198 }
 199
 200 static void tun_detach(struct tun_struct *tun)
 201 {
 202         rtnl_lock();
 203         __tun_detach(tun);
 204         rtnl_unlock();
 205 }
 206
 207 static struct tun_struct *__tun_get(struct tun_file *tfile)
 208 {
 209         struct tun_struct *tun = NULL;
 210
 211         if (atomic_inc_not_zero(&tfile->count))
 212                 tun = tfile->tun;
 213
 214         return tun;
 215 }
 216
 217 static struct tun_struct *tun_get(struct file *file)
 218 {
 219         return __tun_get(file->private_data);
 220 }
 221
 222 static void tun_put(struct tun_struct *tun)
 223 {
 224         struct tun_file *tfile = tun->tfile;
 225
 226         if (atomic_dec_and_test(&tfile->count))
 227                 tun_detach(tfile->tun);
 228 }
 229
 230 /* TAP filtering */
 231 static void addr_hash_set(u32 *mask, const u8 *addr)
 232 {
 233         int n = ether_crc(ETH_ALEN, addr) >> 26;
 234         mask[n >> 5] |= (1 << (n & 31));
 235 }
 236
 237 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 238 {
 239         int n = ether_crc(ETH_ALEN, addr) >> 26;
 240         return mask[n >> 5] & (1 << (n & 31));
 241 }
 242
 243 static int update_filter(struct tap_filter *filter, void __user *arg)
 244 {
 245         struct { u8 u[ETH_ALEN]; } *addr;
 246         struct tun_filter uf;
 247         int err, alen, n, nexact;
 248
 249         if (copy_from_user(&uf, arg, sizeof(uf)))
 250                 return -EFAULT;
 251
 252         if (!uf.count) {
 253                 /* Disabled */
 254                 filter->count = 0;
 255                 return 0;
 256         }
 257
 258         alen = ETH_ALEN * uf.count;
 259         addr = kmalloc(alen, GFP_KERNEL);
 260         if (!addr)
 261                 return -ENOMEM;
 262
 263         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 264                 err = -EFAULT;
 265                 goto done;
 266         }
 267
 268         /* The filter is updated without holding any locks. Which is
 269          * perfectly safe. We disable it first and in the worst
 270          * case we'll accept a few undesired packets. */
 271         filter->count = 0;
 272         wmb();
 273
 274         /* Use first set of addresses as an exact filter */
 275         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 276                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 277
 278         nexact = n;
 279
 280         /* Remaining multicast addresses are hashed,
 281          * unicast will leave the filter disabled. */
 282         memset(filter->mask, 0, sizeof(filter->mask));
 283         for (; n < uf.count; n++) {
 284                 if (!is_multicast_ether_addr(addr[n].u)) {
 285                         err = 0; /* no filter */
 286                         goto done;
 287                 }
 288                 addr_hash_set(filter->mask, addr[n].u);
 289         }
 290
 291         /* For ALLMULTI just set the mask to all ones.
 292          * This overrides the mask populated above. */
 293         if ((uf.flags & TUN_FLT_ALLMULTI))
 294                 memset(filter->mask, ~0, sizeof(filter->mask));
 295
 296         /* Now enable the filter */
 297         wmb();
 298         filter->count = nexact;
 299
 300         /* Return the number of exact filters */
 301         err = nexact;
 302
 303 done:
 304         kfree(addr);
 305         return err;
 306 }
 307
 308 /* Returns: 0 - drop, !=0 - accept */
 309 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 310 {
 311         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 312          * at this point. */
 313         struct ethhdr *eh = (struct ethhdr *) skb->data;
 314         int i;
 315
 316         /* Exact match */
 317         for (i = 0; i < filter->count; i++)
 318                 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
 319                         return 1;
 320
 321         /* Inexact match (multicast only) */
 322         if (is_multicast_ether_addr(eh->h_dest))
 323                 return addr_hash_test(filter->mask, eh->h_dest);
 324
 325         return 0;
 326 }
 327
 328 /*
 329  * Checks whether the packet is accepted or not.
 330  * Returns: 0 - drop, !=0 - accept
 331  */
 332 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 333 {
 334         if (!filter->count)
 335                 return 1;
 336
 337         return run_filter(filter, skb);
 338 }
 339
 340 /* Network device part of the driver */
 341
 342 static const struct ethtool_ops tun_ethtool_ops;
 343
 344 /* Net device detach from fd. */
 345 static void tun_net_uninit(struct net_device *dev)
 346 {
 347         struct tun_struct *tun = netdev_priv(dev);
 348         struct tun_file *tfile = tun->tfile;
 349
 350         /* Inform the methods they need to stop using the dev.
 351          */
 352         if (tfile) {
 353                 wake_up_all(&tun->wq.wait);
 354                 if (atomic_dec_and_test(&tfile->count))
 355                         __tun_detach(tun);
 356         }
 357 }
 358
 359 static void tun_free_netdev(struct net_device *dev)
 360 {
 361         struct tun_struct *tun = netdev_priv(dev);
 362
 363         BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags));
 364
 365         sk_release_kernel(tun->socket.sk);
 366 }
 367
 368 /* Net device open. */
 369 static int tun_net_open(struct net_device *dev)
 370 {
 371         netif_start_queue(dev);
 372         return 0;
 373 }
 374
 375 /* Net device close. */
 376 static int tun_net_close(struct net_device *dev)
 377 {
 378         netif_stop_queue(dev);
 379         return 0;
 380 }
 381
 382 /* Net device start xmit */
 383 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 384 {
 385         struct tun_struct *tun = netdev_priv(dev);
 386
 387         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 388
 389         /* Drop packet if interface is not attached */
 390         if (!tun->tfile)
 391                 goto drop;
 392
 393         /* Drop if the filter does not like it.
 394          * This is a noop if the filter is disabled.
 395          * Filter can be enabled only for the TAP devices. */
 396         if (!check_filter(&tun->txflt, skb))
 397                 goto drop;
 398
 399         if (tun->socket.sk->sk_filter &&
 400             sk_filter(tun->socket.sk, skb))
 401                 goto drop;
 402
 403         if (skb_queue_len(&tun->socket.sk->sk_receive_queue) >= dev->tx_queue_len) {
 404                 if (!(tun->flags & TUN_ONE_QUEUE)) {
 405                         /* Normal queueing mode. */
 406                         /* Packet scheduler handles dropping of further packets. */
 407                         netif_stop_queue(dev);
 408
 409                         /* We won't see all dropped packets individually, so overrun
 410                          * error is more appropriate. */
 411                         dev->stats.tx_fifo_errors++;
 412                 } else {
 413                         /* Single queue mode.
 414                          * Driver handles dropping of all packets itself. */
 415                         goto drop;
 416                 }
 417         }
 418
 419         /* Orphan the skb - required as we might hang on to it
 420          * for indefinite time. */
 421         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
 422                 goto drop;
 423         skb_orphan(skb);
 424
 425         /* Enqueue packet */
 426         skb_queue_tail(&tun->socket.sk->sk_receive_queue, skb);
 427
 428         /* Notify and wake up reader process */
 429         if (tun->flags & TUN_FASYNC)
 430                 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
 431         wake_up_interruptible_poll(&tun->wq.wait, POLLIN |
 432                                    POLLRDNORM | POLLRDBAND);
 433         return NETDEV_TX_OK;
 434
 435 drop:
 436         dev->stats.tx_dropped++;
 437         kfree_skb(skb);
 438         return NETDEV_TX_OK;
 439 }
 440
 441 static void tun_net_mclist(struct net_device *dev)
 442 {
 443         /*
 444          * This callback is supposed to deal with mc filter in
 445          * _rx_ path and has nothing to do with the _tx_ path.
 446          * In rx path we always accept everything userspace gives us.
 447          */
 448 }
 449
 450 #define MIN_MTU 68
 451 #define MAX_MTU 65535
 452
 453 static int
 454 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 455 {
 456         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 457                 return -EINVAL;
 458         dev->mtu = new_mtu;
 459         return 0;
 460 }
 461
 462 static netdev_features_t tun_net_fix_features(struct net_device *dev,
 463         netdev_features_t features)
 464 {
 465         struct tun_struct *tun = netdev_priv(dev);
 466
 467         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 468 }
 469 #ifdef CONFIG_NET_POLL_CONTROLLER
 470 static void tun_poll_controller(struct net_device *dev)
 471 {
 472         /*
 473          * Tun only receives frames when:
 474          * 1) the char device endpoint gets data from user space
 475          * 2) the tun socket gets a sendmsg call from user space
 476          * Since both of those are syncronous operations, we are guaranteed
 477          * never to have pending data when we poll for it
 478          * so theres nothing to do here but return.
 479          * We need this though so netpoll recognizes us as an interface that
 480          * supports polling, which enables bridge devices in virt setups to
 481          * still use netconsole
 482          */
 483         return;
 484 }
 485 #endif
 486 static const struct net_device_ops tun_netdev_ops = {
 487         .ndo_uninit             = tun_net_uninit,
 488         .ndo_open               = tun_net_open,
 489         .ndo_stop               = tun_net_close,
 490         .ndo_start_xmit         = tun_net_xmit,
 491         .ndo_change_mtu         = tun_net_change_mtu,
 492         .ndo_fix_features       = tun_net_fix_features,
 493 #ifdef CONFIG_NET_POLL_CONTROLLER
 494         .ndo_poll_controller    = tun_poll_controller,
 495 #endif
 496 };
 497
 498 static const struct net_device_ops tap_netdev_ops = {
 499         .ndo_uninit             = tun_net_uninit,
 500         .ndo_open               = tun_net_open,
 501         .ndo_stop               = tun_net_close,
 502         .ndo_start_xmit         = tun_net_xmit,
 503         .ndo_change_mtu         = tun_net_change_mtu,
 504         .ndo_fix_features       = tun_net_fix_features,
 505         .ndo_set_rx_mode        = tun_net_mclist,
 506         .ndo_set_mac_address    = eth_mac_addr,
 507         .ndo_validate_addr      = eth_validate_addr,
 508 #ifdef CONFIG_NET_POLL_CONTROLLER
 509         .ndo_poll_controller    = tun_poll_controller,
 510 #endif
 511 };
 512
 513 /* Initialize net device. */
 514 static void tun_net_init(struct net_device *dev)
 515 {
 516         struct tun_struct *tun = netdev_priv(dev);
 517
 518         switch (tun->flags & TUN_TYPE_MASK) {
 519         case TUN_TUN_DEV:
 520                 dev->netdev_ops = &tun_netdev_ops;
 521
 522                 /* Point-to-Point TUN Device */
 523                 dev->hard_header_len = 0;
 524                 dev->addr_len = 0;
 525                 dev->mtu = 1500;
 526
 527                 /* Zero header length */
 528                 dev->type = ARPHRD_NONE;
 529                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 530                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 531                 break;
 532
 533         case TUN_TAP_DEV:
 534                 dev->netdev_ops = &tap_netdev_ops;
 535                 /* Ethernet TAP Device */
 536                 ether_setup(dev);
 537                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 538
 539                 eth_hw_addr_random(dev);
 540
 541                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 542                 break;
 543         }
 544 }
 545
 546 /* Character device part */
 547
 548 /* Poll */
 549 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
 550 {
 551         struct tun_file *tfile = file->private_data;
 552         struct tun_struct *tun = __tun_get(tfile);
 553         struct sock *sk;
 554         unsigned int mask = 0;
 555
 556         if (!tun)
 557                 return POLLERR;
 558
 559         sk = tun->socket.sk;
 560
 561         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
 562
 563         poll_wait(file, &tun->wq.wait, wait);
 564
 565         if (!skb_queue_empty(&sk->sk_receive_queue))
 566                 mask |= POLLIN | POLLRDNORM;
 567
 568         if (sock_writeable(sk) ||
 569             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 570              sock_writeable(sk)))
 571                 mask |= POLLOUT | POLLWRNORM;
 572
 573         if (tun->dev->reg_state != NETREG_REGISTERED)
 574                 mask = POLLERR;
 575
 576         tun_put(tun);
 577         return mask;
 578 }
 579
 580 /* prepad is the amount to reserve at front.  len is length after that.
 581  * linear is a hint as to how much to copy (usually headers). */
 582 static struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
 583                                      size_t prepad, size_t len,
 584                                      size_t linear, int noblock)
 585 {
 586         struct sock *sk = tun->socket.sk;
 587         struct sk_buff *skb;
 588         int err;
 589
 590         sock_update_classid(sk);
 591
 592         /* Under a page?  Don't bother with paged skb. */
 593         if (prepad + len < PAGE_SIZE || !linear)
 594                 linear = len;
 595
 596         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 597                                    &err);
 598         if (!skb)
 599                 return ERR_PTR(err);
 600
 601         skb_reserve(skb, prepad);
 602         skb_put(skb, linear);
 603         skb->data_len = len - linear;
 604         skb->len += len - linear;
 605
 606         return skb;
 607 }
 608
 609 /* set skb frags from iovec, this can move to core network code for reuse */
 610 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
 611                                   int offset, size_t count)
 612 {
 613         int len = iov_length(from, count) - offset;
 614         int copy = skb_headlen(skb);
 615         int size, offset1 = 0;
 616         int i = 0;
 617
 618         /* Skip over from offset */
 619         while (count && (offset >= from->iov_len)) {
 620                 offset -= from->iov_len;
 621                 ++from;
 622                 --count;
 623         }
 624
 625         /* copy up to skb headlen */
 626         while (count && (copy > 0)) {
 627                 size = min_t(unsigned int, copy, from->iov_len - offset);
 628                 if (copy_from_user(skb->data + offset1, from->iov_base + offset,
 629                                    size))
 630                         return -EFAULT;
 631                 if (copy > size) {
 632                         ++from;
 633                         --count;
 634                         offset = 0;
 635                 } else
 636                         offset += size;
 637                 copy -= size;
 638                 offset1 += size;
 639         }
 640
 641         if (len == offset1)
 642                 return 0;
 643
 644         while (count--) {
 645                 struct page *page[MAX_SKB_FRAGS];
 646                 int num_pages;
 647                 unsigned long base;
 648                 unsigned long truesize;
 649
 650                 len = from->iov_len - offset;
 651                 if (!len) {
 652                         offset = 0;
 653                         ++from;
 654                         continue;
 655                 }
 656                 base = (unsigned long)from->iov_base + offset;
 657                 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
 658                 if (i + size > MAX_SKB_FRAGS)
 659                         return -EMSGSIZE;
 660                 num_pages = get_user_pages_fast(base, size, 0, &page[i]);
 661                 if (num_pages != size) {
 662                         for (i = 0; i < num_pages; i++)
 663                                 put_page(page[i]);
 664                         return -EFAULT;
 665                 }
 666                 truesize = size * PAGE_SIZE;
 667                 skb->data_len += len;
 668                 skb->len += len;
 669                 skb->truesize += truesize;
 670                 atomic_add(truesize, &skb->sk->sk_wmem_alloc);
 671                 while (len) {
 672                         int off = base & ~PAGE_MASK;
 673                         int size = min_t(int, len, PAGE_SIZE - off);
 674                         __skb_fill_page_desc(skb, i, page[i], off, size);
 675                         skb_shinfo(skb)->nr_frags++;
 676                         /* increase sk_wmem_alloc */
 677                         base += size;
 678                         len -= size;
 679                         i++;
 680                 }
 681                 offset = 0;
 682                 ++from;
 683         }
 684         return 0;
 685 }
 686
 687 /* Get packet from user space buffer */
 688 static ssize_t tun_get_user(struct tun_struct *tun, void *msg_control,
 689                             const struct iovec *iv, size_t total_len,
 690                             size_t count, int noblock)
 691 {
 692         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
 693         struct sk_buff *skb;
 694         size_t len = total_len, align = NET_SKB_PAD;
 695         struct virtio_net_hdr gso = { 0 };
 696         int offset = 0;
 697         int copylen;
 698         bool zerocopy = false;
 699         int err;
 700
 701         if (!(tun->flags & TUN_NO_PI)) {
 702                 if ((len -= sizeof(pi)) > total_len)
 703                         return -EINVAL;
 704
 705                 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
 706                         return -EFAULT;
 707                 offset += sizeof(pi);
 708         }
 709
 710         if (tun->flags & TUN_VNET_HDR) {
 711                 if ((len -= tun->vnet_hdr_sz) > total_len)
 712                         return -EINVAL;
 713
 714                 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
 715                         return -EFAULT;
 716
 717                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
 718                     gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
 719                         gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
 720
 721                 if (gso.hdr_len > len)
 722                         return -EINVAL;
 723                 offset += tun->vnet_hdr_sz;
 724         }
 725
 726         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
 727                 align += NET_IP_ALIGN;
 728                 if (unlikely(len < ETH_HLEN ||
 729                              (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
 730                         return -EINVAL;
 731         }
 732
 733         if (msg_control)
 734                 zerocopy = true;
 735
 736         if (zerocopy) {
 737                 /* Userspace may produce vectors with count greater than
 738                  * MAX_SKB_FRAGS, so we need to linearize parts of the skb
 739                  * to let the rest of data to be fit in the frags.
 740                  */
 741                 if (count > MAX_SKB_FRAGS) {
 742                         copylen = iov_length(iv, count - MAX_SKB_FRAGS);
 743                         if (copylen < offset)
 744                                 copylen = 0;
 745                         else
 746                                 copylen -= offset;
 747                 } else
 748                                 copylen = 0;
 749                 /* There are 256 bytes to be copied in skb, so there is enough
 750                  * room for skb expand head in case it is used.
 751                  * The rest of the buffer is mapped from userspace.
 752                  */
 753                 if (copylen < gso.hdr_len)
 754                         copylen = gso.hdr_len;
 755                 if (!copylen)
 756                         copylen = GOODCOPY_LEN;
 757         } else
 758                 copylen = len;
 759
 760         skb = tun_alloc_skb(tun, align, copylen, gso.hdr_len, noblock);
 761         if (IS_ERR(skb)) {
 762                 if (PTR_ERR(skb) != -EAGAIN)
 763                         tun->dev->stats.rx_dropped++;
 764                 return PTR_ERR(skb);
 765         }
 766
 767         if (zerocopy)
 768                 err = zerocopy_sg_from_iovec(skb, iv, offset, count);
 769         else
 770                 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
 771
 772         if (err) {
 773                 tun->dev->stats.rx_dropped++;
 774                 kfree_skb(skb);
 775                 return -EFAULT;
 776         }
 777
 778         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 779                 if (!skb_partial_csum_set(skb, gso.csum_start,
 780                                           gso.csum_offset)) {
 781                         tun->dev->stats.rx_frame_errors++;
 782                         kfree_skb(skb);
 783                         return -EINVAL;
 784                 }
 785         }
 786
 787         switch (tun->flags & TUN_TYPE_MASK) {
 788         case TUN_TUN_DEV:
 789                 if (tun->flags & TUN_NO_PI) {
 790                         switch (skb->data[0] & 0xf0) {
 791                         case 0x40:
 792                                 pi.proto = htons(ETH_P_IP);
 793                                 break;
 794                         case 0x60:
 795                                 pi.proto = htons(ETH_P_IPV6);
 796                                 break;
 797                         default:
 798                                 tun->dev->stats.rx_dropped++;
 799                                 kfree_skb(skb);
 800                                 return -EINVAL;
 801                         }
 802                 }
 803
 804                 skb_reset_mac_header(skb);
 805                 skb->protocol = pi.proto;
 806                 skb->dev = tun->dev;
 807                 break;
 808         case TUN_TAP_DEV:
 809                 skb->protocol = eth_type_trans(skb, tun->dev);
 810                 break;
 811         }
 812
 813         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 814                 pr_debug("GSO!\n");
 815                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 816                 case VIRTIO_NET_HDR_GSO_TCPV4:
 817                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 818                         break;
 819                 case VIRTIO_NET_HDR_GSO_TCPV6:
 820                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 821                         break;
 822                 case VIRTIO_NET_HDR_GSO_UDP:
 823                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 824                         break;
 825                 default:
 826                         tun->dev->stats.rx_frame_errors++;
 827                         kfree_skb(skb);
 828                         return -EINVAL;
 829                 }
 830
 831                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 832                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 833
 834                 skb_shinfo(skb)->gso_size = gso.gso_size;
 835                 if (skb_shinfo(skb)->gso_size == 0) {
 836                         tun->dev->stats.rx_frame_errors++;
 837                         kfree_skb(skb);
 838                         return -EINVAL;
 839                 }
 840
 841                 /* Header must be checked, and gso_segs computed. */
 842                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 843                 skb_shinfo(skb)->gso_segs = 0;
 844         }
 845
 846         /* copy skb_ubuf_info for callback when skb has no error */
 847         if (zerocopy) {
 848                 skb_shinfo(skb)->destructor_arg = msg_control;
 849                 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
 850         }
 851
 852         netif_rx_ni(skb);
 853
 854         tun->dev->stats.rx_packets++;
 855         tun->dev->stats.rx_bytes += len;
 856
 857         return total_len;
 858 }
 859
 860 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 861                               unsigned long count, loff_t pos)
 862 {
 863         struct file *file = iocb->ki_filp;
 864         struct tun_struct *tun = tun_get(file);
 865         ssize_t result;
 866
 867         if (!tun)
 868                 return -EBADFD;
 869
 870         tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
 871
 872         result = tun_get_user(tun, NULL, iv, iov_length(iv, count), count,
 873                               file->f_flags & O_NONBLOCK);
 874
 875         tun_put(tun);
 876         return result;
 877 }
 878
 879 /* Put packet to the user space buffer */
 880 static ssize_t tun_put_user(struct tun_struct *tun,
 881                             struct sk_buff *skb,
 882                             const struct iovec *iv, int len)
 883 {
 884         struct tun_pi pi = { 0, skb->protocol };
 885         ssize_t total = 0;
 886
 887         if (!(tun->flags & TUN_NO_PI)) {
 888                 if ((len -= sizeof(pi)) < 0)
 889                         return -EINVAL;
 890
 891                 if (len < skb->len) {
 892                         /* Packet will be striped */
 893                         pi.flags |= TUN_PKT_STRIP;
 894                 }
 895
 896                 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
 897                         return -EFAULT;
 898                 total += sizeof(pi);
 899         }
 900
 901         if (tun->flags & TUN_VNET_HDR) {
 902                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
 903                 if ((len -= tun->vnet_hdr_sz) < 0)
 904                         return -EINVAL;
 905
 906                 if (skb_is_gso(skb)) {
 907                         struct skb_shared_info *sinfo = skb_shinfo(skb);
 908
 909                         /* This is a hint as to how much should be linear. */
 910                         gso.hdr_len = skb_headlen(skb);
 911                         gso.gso_size = sinfo->gso_size;
 912                         if (sinfo->gso_type & SKB_GSO_TCPV4)
 913                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 914                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
 915                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 916                         else if (sinfo->gso_type & SKB_GSO_UDP)
 917                                 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 918                         else {
 919                                 pr_err("unexpected GSO type: "
 920                                        "0x%x, gso_size %d, hdr_len %d\n",
 921                                        sinfo->gso_type, gso.gso_size,
 922                                        gso.hdr_len);
 923                                 print_hex_dump(KERN_ERR, "tun: ",
 924                                                DUMP_PREFIX_NONE,
 925                                                16, 1, skb->head,
 926                                                min((int)gso.hdr_len, 64), true);
 927                                 WARN_ON_ONCE(1);
 928                                 return -EINVAL;
 929                         }
 930                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 931                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 932                 } else
 933                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 934
 935                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
 936                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 937                         gso.csum_start = skb_checksum_start_offset(skb);
 938                         gso.csum_offset = skb->csum_offset;
 939                 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
 940                         gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
 941                 } /* else everything is zero */
 942
 943                 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
 944                                                sizeof(gso))))
 945                         return -EFAULT;
 946                 total += tun->vnet_hdr_sz;
 947         }
 948
 949         len = min_t(int, skb->len, len);
 950
 951         skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
 952         total += skb->len;
 953
 954         tun->dev->stats.tx_packets++;
 955         tun->dev->stats.tx_bytes += len;
 956
 957         return total;
 958 }
 959
 960 static ssize_t tun_do_read(struct tun_struct *tun,
 961                            struct kiocb *iocb, const struct iovec *iv,
 962                            ssize_t len, int noblock)
 963 {
 964         DECLARE_WAITQUEUE(wait, current);
 965         struct sk_buff *skb;
 966         ssize_t ret = 0;
 967
 968         tun_debug(KERN_INFO, tun, "tun_chr_read\n");
 969
 970         if (unlikely(!noblock))
 971                 add_wait_queue(&tun->wq.wait, &wait);
 972         while (len) {
 973                 current->state = TASK_INTERRUPTIBLE;
 974
 975                 /* Read frames from the queue */
 976                 if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) {
 977                         if (noblock) {
 978                                 ret = -EAGAIN;
 979                                 break;
 980                         }
 981                         if (signal_pending(current)) {
 982                                 ret = -ERESTARTSYS;
 983                                 break;
 984                         }
 985                         if (tun->dev->reg_state != NETREG_REGISTERED) {
 986                                 ret = -EIO;
 987                                 break;
 988                         }
 989
 990                         /* Nothing to read, let's sleep */
 991                         schedule();
 992                         continue;
 993                 }
 994                 netif_wake_queue(tun->dev);
 995
 996                 ret = tun_put_user(tun, skb, iv, len);
 997                 kfree_skb(skb);
 998                 break;
 999         }
1000
1001         current->state = TASK_RUNNING;
1002         if (unlikely(!noblock))
1003                 remove_wait_queue(&tun->wq.wait, &wait);
1004
1005         return ret;
1006 }
1007
1008 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1009                             unsigned long count, loff_t pos)
1010 {
1011         struct file *file = iocb->ki_filp;
1012         struct tun_file *tfile = file->private_data;
1013         struct tun_struct *tun = __tun_get(tfile);
1014         ssize_t len, ret;
1015
1016         if (!tun)
1017                 return -EBADFD;
1018         len = iov_length(iv, count);
1019         if (len < 0) {
1020                 ret = -EINVAL;
1021                 goto out;
1022         }
1023
1024         ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK);
1025         ret = min_t(ssize_t, ret, len);
1026 out:
1027         tun_put(tun);
1028         return ret;
1029 }
1030
1031 static void tun_setup(struct net_device *dev)
1032 {
1033         struct tun_struct *tun = netdev_priv(dev);
1034
1035         tun->owner = INVALID_UID;
1036         tun->group = INVALID_GID;
1037
1038         dev->ethtool_ops = &tun_ethtool_ops;
1039         dev->destructor = tun_free_netdev;
1040 }
1041
1042 /* Trivial set of netlink ops to allow deleting tun or tap
1043  * device with netlink.
1044  */
1045 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1046 {
1047         return -EINVAL;
1048 }
1049
1050 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1051         .kind           = DRV_NAME,
1052         .priv_size      = sizeof(struct tun_struct),
1053         .setup          = tun_setup,
1054         .validate       = tun_validate,
1055 };
1056
1057 static void tun_sock_write_space(struct sock *sk)
1058 {
1059         struct tun_struct *tun;
1060         wait_queue_head_t *wqueue;
1061
1062         if (!sock_writeable(sk))
1063                 return;
1064
1065         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1066                 return;
1067
1068         wqueue = sk_sleep(sk);
1069         if (wqueue && waitqueue_active(wqueue))
1070                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1071                                                 POLLWRNORM | POLLWRBAND);
1072
1073         tun = tun_sk(sk)->tun;
1074         kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
1075 }
1076
1077 static void tun_sock_destruct(struct sock *sk)
1078 {
1079         free_netdev(tun_sk(sk)->tun->dev);
1080 }
1081
1082 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1083                        struct msghdr *m, size_t total_len)
1084 {
1085         struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
1086         return tun_get_user(tun, m->msg_control, m->msg_iov, total_len,
1087                             m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1088 }
1089
1090 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1091                        struct msghdr *m, size_t total_len,
1092                        int flags)
1093 {
1094         struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
1095         int ret;
1096         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1097                 return -EINVAL;
1098         ret = tun_do_read(tun, iocb, m->msg_iov, total_len,
1099                           flags & MSG_DONTWAIT);
1100         if (ret > total_len) {
1101                 m->msg_flags |= MSG_TRUNC;
1102                 ret = flags & MSG_TRUNC ? ret : total_len;
1103         }
1104         return ret;
1105 }
1106
1107 static int tun_release(struct socket *sock)
1108 {
1109         if (sock->sk)
1110                 sock_put(sock->sk);
1111         return 0;
1112 }
1113
1114 /* Ops structure to mimic raw sockets with tun */
1115 static const struct proto_ops tun_socket_ops = {
1116         .sendmsg = tun_sendmsg,
1117         .recvmsg = tun_recvmsg,
1118         .release = tun_release,
1119 };
1120
1121 static struct proto tun_proto = {
1122         .name           = "tun",
1123         .owner          = THIS_MODULE,
1124         .obj_size       = sizeof(struct tun_sock),
1125 };
1126
1127 static int tun_flags(struct tun_struct *tun)
1128 {
1129         int flags = 0;
1130
1131         if (tun->flags & TUN_TUN_DEV)
1132                 flags |= IFF_TUN;
1133         else
1134                 flags |= IFF_TAP;
1135
1136         if (tun->flags & TUN_NO_PI)
1137                 flags |= IFF_NO_PI;
1138
1139         if (tun->flags & TUN_ONE_QUEUE)
1140                 flags |= IFF_ONE_QUEUE;
1141
1142         if (tun->flags & TUN_VNET_HDR)
1143                 flags |= IFF_VNET_HDR;
1144
1145         return flags;
1146 }
1147
1148 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1149                               char *buf)
1150 {
1151         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1152         return sprintf(buf, "0x%x\n", tun_flags(tun));
1153 }
1154
1155 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1156                               char *buf)
1157 {
1158         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1159         return uid_valid(tun->owner)?
1160                 sprintf(buf, "%u\n",
1161                         from_kuid_munged(current_user_ns(), tun->owner)):
1162                 sprintf(buf, "-1\n");
1163 }
1164
1165 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1166                               char *buf)
1167 {
1168         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1169         return gid_valid(tun->group) ?
1170                 sprintf(buf, "%u\n",
1171                         from_kgid_munged(current_user_ns(), tun->group)):
1172                 sprintf(buf, "-1\n");
1173 }
1174
1175 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1176 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1177 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1178
1179 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1180 {
1181         struct sock *sk;
1182         struct tun_struct *tun;
1183         struct net_device *dev;
1184         int err;
1185
1186         dev = __dev_get_by_name(net, ifr->ifr_name);
1187         if (dev) {
1188                 const struct cred *cred = current_cred();
1189
1190                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1191                         return -EBUSY;
1192                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1193                         tun = netdev_priv(dev);
1194                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1195                         tun = netdev_priv(dev);
1196                 else
1197                         return -EINVAL;
1198
1199                 if (((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
1200                      (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
1201                     !capable(CAP_NET_ADMIN))
1202                         return -EPERM;
1203                 err = security_tun_dev_attach(tun->socket.sk);
1204                 if (err < 0)
1205                         return err;
1206
1207                 err = tun_attach(tun, file);
1208                 if (err < 0)
1209                         return err;
1210         }
1211         else {
1212                 char *name;
1213                 unsigned long flags = 0;
1214
1215                 if (!capable(CAP_NET_ADMIN))
1216                         return -EPERM;
1217                 err = security_tun_dev_create();
1218                 if (err < 0)
1219                         return err;
1220
1221                 /* Set dev type */
1222                 if (ifr->ifr_flags & IFF_TUN) {
1223                         /* TUN device */
1224                         flags |= TUN_TUN_DEV;
1225                         name = "tun%d";
1226                 } else if (ifr->ifr_flags & IFF_TAP) {
1227                         /* TAP device */
1228                         flags |= TUN_TAP_DEV;
1229                         name = "tap%d";
1230                 } else
1231                         return -EINVAL;
1232
1233                 if (*ifr->ifr_name)
1234                         name = ifr->ifr_name;
1235
1236                 dev = alloc_netdev(sizeof(struct tun_struct), name,
1237                                    tun_setup);
1238                 if (!dev)
1239                         return -ENOMEM;
1240
1241                 dev_net_set(dev, net);
1242                 dev->rtnl_link_ops = &tun_link_ops;
1243
1244                 tun = netdev_priv(dev);
1245                 tun->dev = dev;
1246                 tun->flags = flags;
1247                 tun->txflt.count = 0;
1248                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1249                 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags);
1250
1251                 err = -ENOMEM;
1252                 sk = sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
1253                 if (!sk)
1254                         goto err_free_dev;
1255
1256                 sk_change_net(sk, net);
1257                 tun->socket.wq = &tun->wq;
1258                 init_waitqueue_head(&tun->wq.wait);
1259                 tun->socket.ops = &tun_socket_ops;
1260                 sock_init_data(&tun->socket, sk);
1261                 sk->sk_write_space = tun_sock_write_space;
1262                 sk->sk_sndbuf = INT_MAX;
1263                 sock_set_flag(sk, SOCK_ZEROCOPY);
1264
1265                 tun_sk(sk)->tun = tun;
1266
1267                 security_tun_dev_post_create(sk);
1268
1269                 tun_net_init(dev);
1270
1271                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1272                         TUN_USER_FEATURES;
1273                 dev->features = dev->hw_features;
1274
1275                 err = register_netdevice(tun->dev);
1276                 if (err < 0)
1277                         goto err_free_sk;
1278
1279                 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1280                     device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1281                     device_create_file(&tun->dev->dev, &dev_attr_group))
1282                         pr_err("Failed to create tun sysfs files\n");
1283
1284                 sk->sk_destruct = tun_sock_destruct;
1285
1286                 err = tun_attach(tun, file);
1287                 if (err < 0)
1288                         goto failed;
1289         }
1290
1291         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1292
1293         if (ifr->ifr_flags & IFF_NO_PI)
1294                 tun->flags |= TUN_NO_PI;
1295         else
1296                 tun->flags &= ~TUN_NO_PI;
1297
1298         if (ifr->ifr_flags & IFF_ONE_QUEUE)
1299                 tun->flags |= TUN_ONE_QUEUE;
1300         else
1301                 tun->flags &= ~TUN_ONE_QUEUE;
1302
1303         if (ifr->ifr_flags & IFF_VNET_HDR)
1304                 tun->flags |= TUN_VNET_HDR;
1305         else
1306                 tun->flags &= ~TUN_VNET_HDR;
1307
1308         /* Make sure persistent devices do not get stuck in
1309          * xoff state.
1310          */
1311         if (netif_running(tun->dev))
1312                 netif_wake_queue(tun->dev);
1313
1314         strcpy(ifr->ifr_name, tun->dev->name);
1315         return 0;
1316
1317  err_free_sk:
1318         tun_free_netdev(dev);
1319  err_free_dev:
1320         free_netdev(dev);
1321  failed:
1322         return err;
1323 }
1324
1325 static int tun_get_iff(struct net *net, struct tun_struct *tun,
1326                        struct ifreq *ifr)
1327 {
1328         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1329
1330         strcpy(ifr->ifr_name, tun->dev->name);
1331
1332         ifr->ifr_flags = tun_flags(tun);
1333
1334         return 0;
1335 }
1336
1337 /* This is like a cut-down ethtool ops, except done via tun fd so no
1338  * privs required. */
1339 static int set_offload(struct tun_struct *tun, unsigned long arg)
1340 {
1341         netdev_features_t features = 0;
1342
1343         if (arg & TUN_F_CSUM) {
1344                 features |= NETIF_F_HW_CSUM;
1345                 arg &= ~TUN_F_CSUM;
1346
1347                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1348                         if (arg & TUN_F_TSO_ECN) {
1349                                 features |= NETIF_F_TSO_ECN;
1350                                 arg &= ~TUN_F_TSO_ECN;
1351                         }
1352                         if (arg & TUN_F_TSO4)
1353                                 features |= NETIF_F_TSO;
1354                         if (arg & TUN_F_TSO6)
1355                                 features |= NETIF_F_TSO6;
1356                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1357                 }
1358
1359                 if (arg & TUN_F_UFO) {
1360                         features |= NETIF_F_UFO;
1361                         arg &= ~TUN_F_UFO;
1362                 }
1363         }
1364
1365         /* This gives the user a way to test for new features in future by
1366          * trying to set them. */
1367         if (arg)
1368                 return -EINVAL;
1369
1370         tun->set_features = features;
1371         netdev_update_features(tun->dev);
1372
1373         return 0;
1374 }
1375
1376 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1377                             unsigned long arg, int ifreq_len)
1378 {
1379         struct tun_file *tfile = file->private_data;
1380         struct tun_struct *tun;
1381         void __user* argp = (void __user*)arg;
1382         struct sock_fprog fprog;
1383         struct ifreq ifr;
1384         kuid_t owner;
1385         kgid_t group;
1386         int sndbuf;
1387         int vnet_hdr_sz;
1388         int ret;
1389
1390         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) {
1391                 if (copy_from_user(&ifr, argp, ifreq_len))
1392                         return -EFAULT;
1393         } else {
1394                 memset(&ifr, 0, sizeof(ifr));
1395         }
1396         if (cmd == TUNGETFEATURES) {
1397                 /* Currently this just means: "what IFF flags are valid?".
1398                  * This is needed because we never checked for invalid flags on
1399                  * TUNSETIFF. */
1400                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1401                                 IFF_VNET_HDR,
1402                                 (unsigned int __user*)argp);
1403         }
1404
1405         rtnl_lock();
1406
1407         tun = __tun_get(tfile);
1408         if (cmd == TUNSETIFF && !tun) {
1409                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1410
1411                 ret = tun_set_iff(tfile->net, file, &ifr);
1412
1413                 if (ret)
1414                         goto unlock;
1415
1416                 if (copy_to_user(argp, &ifr, ifreq_len))
1417                         ret = -EFAULT;
1418                 goto unlock;
1419         }
1420
1421         ret = -EBADFD;
1422         if (!tun)
1423                 goto unlock;
1424
1425         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %d\n", cmd);
1426
1427         ret = 0;
1428         switch (cmd) {
1429         case TUNGETIFF:
1430                 ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1431                 if (ret)
1432                         break;
1433
1434                 if (copy_to_user(argp, &ifr, ifreq_len))
1435                         ret = -EFAULT;
1436                 break;
1437
1438         case TUNSETNOCSUM:
1439                 /* Disable/Enable checksum */
1440
1441                 /* [unimplemented] */
1442                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1443                           arg ? "disabled" : "enabled");
1444                 break;
1445
1446         case TUNSETPERSIST:
1447                 /* Disable/Enable persist mode */
1448                 if (arg)
1449                         tun->flags |= TUN_PERSIST;
1450                 else
1451                         tun->flags &= ~TUN_PERSIST;
1452
1453                 tun_debug(KERN_INFO, tun, "persist %s\n",
1454                           arg ? "enabled" : "disabled");
1455                 break;
1456
1457         case TUNSETOWNER:
1458                 /* Set owner of the device */
1459                 owner = make_kuid(current_user_ns(), arg);
1460                 if (!uid_valid(owner)) {
1461                         ret = -EINVAL;
1462                         break;
1463                 }
1464                 tun->owner = owner;
1465                 tun_debug(KERN_INFO, tun, "owner set to %d\n",
1466                           from_kuid(&init_user_ns, tun->owner));
1467                 break;
1468
1469         case TUNSETGROUP:
1470                 /* Set group of the device */
1471                 group = make_kgid(current_user_ns(), arg);
1472                 if (!gid_valid(group)) {
1473                         ret = -EINVAL;
1474                         break;
1475                 }
1476                 tun->group = group;
1477                 tun_debug(KERN_INFO, tun, "group set to %d\n",
1478                           from_kgid(&init_user_ns, tun->group));
1479                 break;
1480
1481         case TUNSETLINK:
1482                 /* Only allow setting the type when the interface is down */
1483                 if (tun->dev->flags & IFF_UP) {
1484                         tun_debug(KERN_INFO, tun,
1485                                   "Linktype set failed because interface is up\n");
1486                         ret = -EBUSY;
1487                 } else {
1488                         tun->dev->type = (int) arg;
1489                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1490                                   tun->dev->type);
1491                         ret = 0;
1492                 }
1493                 break;
1494
1495 #ifdef TUN_DEBUG
1496         case TUNSETDEBUG:
1497                 tun->debug = arg;
1498                 break;
1499 #endif
1500         case TUNSETOFFLOAD:
1501                 ret = set_offload(tun, arg);
1502                 break;
1503
1504         case TUNSETTXFILTER:
1505                 /* Can be set only for TAPs */
1506                 ret = -EINVAL;
1507                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1508                         break;
1509                 ret = update_filter(&tun->txflt, (void __user *)arg);
1510                 break;
1511
1512         case SIOCGIFHWADDR:
1513                 /* Get hw address */
1514                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1515                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1516                 if (copy_to_user(argp, &ifr, ifreq_len))
1517                         ret = -EFAULT;
1518                 break;
1519
1520         case SIOCSIFHWADDR:
1521                 /* Set hw address */
1522                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1523                           ifr.ifr_hwaddr.sa_data);
1524
1525                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1526                 break;
1527
1528         case TUNGETSNDBUF:
1529                 sndbuf = tun->socket.sk->sk_sndbuf;
1530                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1531                         ret = -EFAULT;
1532                 break;
1533
1534         case TUNSETSNDBUF:
1535                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1536                         ret = -EFAULT;
1537                         break;
1538                 }
1539
1540                 tun->socket.sk->sk_sndbuf = sndbuf;
1541                 break;
1542
1543         case TUNGETVNETHDRSZ:
1544                 vnet_hdr_sz = tun->vnet_hdr_sz;
1545                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
1546                         ret = -EFAULT;
1547                 break;
1548
1549         case TUNSETVNETHDRSZ:
1550                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
1551                         ret = -EFAULT;
1552                         break;
1553                 }
1554                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
1555                         ret = -EINVAL;
1556                         break;
1557                 }
1558
1559                 tun->vnet_hdr_sz = vnet_hdr_sz;
1560                 break;
1561
1562         case TUNATTACHFILTER:
1563                 /* Can be set only for TAPs */
1564                 ret = -EINVAL;
1565                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1566                         break;
1567                 ret = -EFAULT;
1568                 if (copy_from_user(&fprog, argp, sizeof(fprog)))
1569                         break;
1570
1571                 ret = sk_attach_filter(&fprog, tun->socket.sk);
1572                 break;
1573
1574         case TUNDETACHFILTER:
1575                 /* Can be set only for TAPs */
1576                 ret = -EINVAL;
1577                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1578                         break;
1579                 ret = sk_detach_filter(tun->socket.sk);
1580                 break;
1581
1582         default:
1583                 ret = -EINVAL;
1584                 break;
1585         }
1586
1587 unlock:
1588         rtnl_unlock();
1589         if (tun)
1590                 tun_put(tun);
1591         return ret;
1592 }
1593
1594 static long tun_chr_ioctl(struct file *file,
1595                           unsigned int cmd, unsigned long arg)
1596 {
1597         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
1598 }
1599
1600 #ifdef CONFIG_COMPAT
1601 static long tun_chr_compat_ioctl(struct file *file,
1602                          unsigned int cmd, unsigned long arg)
1603 {
1604         switch (cmd) {
1605         case TUNSETIFF:
1606         case TUNGETIFF:
1607         case TUNSETTXFILTER:
1608         case TUNGETSNDBUF:
1609         case TUNSETSNDBUF:
1610         case SIOCGIFHWADDR:
1611         case SIOCSIFHWADDR:
1612                 arg = (unsigned long)compat_ptr(arg);
1613                 break;
1614         default:
1615                 arg = (compat_ulong_t)arg;
1616                 break;
1617         }
1618
1619         /*
1620          * compat_ifreq is shorter than ifreq, so we must not access beyond
1621          * the end of that structure. All fields that are used in this
1622          * driver are compatible though, we don't need to convert the
1623          * contents.
1624          */
1625         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
1626 }
1627 #endif /* CONFIG_COMPAT */
1628
1629 static int tun_chr_fasync(int fd, struct file *file, int on)
1630 {
1631         struct tun_struct *tun = tun_get(file);
1632         int ret;
1633
1634         if (!tun)
1635                 return -EBADFD;
1636
1637         tun_debug(KERN_INFO, tun, "tun_chr_fasync %d\n", on);
1638
1639         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1640                 goto out;
1641
1642         if (on) {
1643                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1644                 if (ret)
1645                         goto out;
1646                 tun->flags |= TUN_FASYNC;
1647         } else
1648                 tun->flags &= ~TUN_FASYNC;
1649         ret = 0;
1650 out:
1651         tun_put(tun);
1652         return ret;
1653 }
1654
1655 static int tun_chr_open(struct inode *inode, struct file * file)
1656 {
1657         struct tun_file *tfile;
1658
1659         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
1660
1661         tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1662         if (!tfile)
1663                 return -ENOMEM;
1664         atomic_set(&tfile->count, 0);
1665         tfile->tun = NULL;
1666         tfile->net = get_net(current->nsproxy->net_ns);
1667         file->private_data = tfile;
1668         return 0;
1669 }
1670
1671 static int tun_chr_close(struct inode *inode, struct file *file)
1672 {
1673         struct tun_file *tfile = file->private_data;
1674         struct tun_struct *tun;
1675
1676         tun = __tun_get(tfile);
1677         if (tun) {
1678                 struct net_device *dev = tun->dev;
1679
1680                 tun_debug(KERN_INFO, tun, "tun_chr_close\n");
1681
1682                 __tun_detach(tun);
1683
1684                 /* If desirable, unregister the netdevice. */
1685                 if (!(tun->flags & TUN_PERSIST)) {
1686                         rtnl_lock();
1687                         if (dev->reg_state == NETREG_REGISTERED)
1688                                 unregister_netdevice(dev);
1689                         rtnl_unlock();
1690                 }
1691         }
1692
1693         tun = tfile->tun;
1694         if (tun)
1695                 sock_put(tun->socket.sk);
1696
1697         put_net(tfile->net);
1698         kfree(tfile);
1699
1700         return 0;
1701 }
1702
1703 static const struct file_operations tun_fops = {
1704         .owner  = THIS_MODULE,
1705         .llseek = no_llseek,
1706         .read  = do_sync_read,
1707         .aio_read  = tun_chr_aio_read,
1708         .write = do_sync_write,
1709         .aio_write = tun_chr_aio_write,
1710         .poll   = tun_chr_poll,
1711         .unlocked_ioctl = tun_chr_ioctl,
1712 #ifdef CONFIG_COMPAT
1713         .compat_ioctl = tun_chr_compat_ioctl,
1714 #endif
1715         .open   = tun_chr_open,
1716         .release = tun_chr_close,
1717         .fasync = tun_chr_fasync
1718 };
1719
1720 static struct miscdevice tun_miscdev = {
1721         .minor = TUN_MINOR,
1722         .name = "tun",
1723         .nodename = "net/tun",
1724         .fops = &tun_fops,
1725 };
1726
1727 /* ethtool interface */
1728
1729 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1730 {
1731         cmd->supported          = 0;
1732         cmd->advertising        = 0;
1733         ethtool_cmd_speed_set(cmd, SPEED_10);
1734         cmd->duplex             = DUPLEX_FULL;
1735         cmd->port               = PORT_TP;
1736         cmd->phy_address        = 0;
1737         cmd->transceiver        = XCVR_INTERNAL;
1738         cmd->autoneg            = AUTONEG_DISABLE;
1739         cmd->maxtxpkt           = 0;
1740         cmd->maxrxpkt           = 0;
1741         return 0;
1742 }
1743
1744 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1745 {
1746         struct tun_struct *tun = netdev_priv(dev);
1747
1748         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
1749         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
1750
1751         switch (tun->flags & TUN_TYPE_MASK) {
1752         case TUN_TUN_DEV:
1753                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
1754                 break;
1755         case TUN_TAP_DEV:
1756                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
1757                 break;
1758         }
1759 }
1760
1761 static u32 tun_get_msglevel(struct net_device *dev)
1762 {
1763 #ifdef TUN_DEBUG
1764         struct tun_struct *tun = netdev_priv(dev);
1765         return tun->debug;
1766 #else
1767         return -EOPNOTSUPP;
1768 #endif
1769 }
1770
1771 static void tun_set_msglevel(struct net_device *dev, u32 value)
1772 {
1773 #ifdef TUN_DEBUG
1774         struct tun_struct *tun = netdev_priv(dev);
1775         tun->debug = value;
1776 #endif
1777 }
1778
1779 static const struct ethtool_ops tun_ethtool_ops = {
1780         .get_settings   = tun_get_settings,
1781         .get_drvinfo    = tun_get_drvinfo,
1782         .get_msglevel   = tun_get_msglevel,
1783         .set_msglevel   = tun_set_msglevel,
1784         .get_link       = ethtool_op_get_link,
1785 };
1786
1787
1788 static int __init tun_init(void)
1789 {
1790         int ret = 0;
1791
1792         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1793         pr_info("%s\n", DRV_COPYRIGHT);
1794
1795         ret = rtnl_link_register(&tun_link_ops);
1796         if (ret) {
1797                 pr_err("Can't register link_ops\n");
1798                 goto err_linkops;
1799         }
1800
1801         ret = misc_register(&tun_miscdev);
1802         if (ret) {
1803                 pr_err("Can't register misc device %d\n", TUN_MINOR);
1804                 goto err_misc;
1805         }
1806         return  0;
1807 err_misc:
1808         rtnl_link_unregister(&tun_link_ops);
1809 err_linkops:
1810         return ret;
1811 }
1812
1813 static void tun_cleanup(void)
1814 {
1815         misc_deregister(&tun_miscdev);
1816         rtnl_link_unregister(&tun_link_ops);
1817 }
1818
1819 /* Get an underlying socket object from tun file.  Returns error unless file is
1820  * attached to a device.  The returned object works like a packet socket, it
1821  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
1822  * holding a reference to the file for as long as the socket is in use. */
1823 struct socket *tun_get_socket(struct file *file)
1824 {
1825         struct tun_struct *tun;
1826         if (file->f_op != &tun_fops)
1827                 return ERR_PTR(-EINVAL);
1828         tun = tun_get(file);
1829         if (!tun)
1830                 return ERR_PTR(-EBADFD);
1831         tun_put(tun);
1832         return &tun->socket;
1833 }
1834 EXPORT_SYMBOL_GPL(tun_get_socket);
1835
1836 module_init(tun_init);
1837 module_exit(tun_cleanup);
1838 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1839 MODULE_AUTHOR(DRV_COPYRIGHT);
1840 MODULE_LICENSE("GPL");
1841 MODULE_ALIAS_MISCDEV(TUN_MINOR);
1842 MODULE_ALIAS("devname:net/tun");