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
  72 #include <asm/uaccess.h>
  73
  74 /* Uncomment to enable debugging */
  75 /* #define TUN_DEBUG 1 */
  76
  77 #ifdef TUN_DEBUG
  78 static int debug;
  79
  80 #define tun_debug(level, tun, fmt, args...)                     \
  81 do {                                                            \
  82         if (tun->debug)                                         \
  83                 netdev_printk(level, tun->dev, fmt, ##args);    \
  84 } while (0)
  85 #define DBG1(level, fmt, args...)                               \
  86 do {                                                            \
  87         if (debug == 2)                                         \
  88                 printk(level fmt, ##args);                      \
  89 } while (0)
  90 #else
  91 #define tun_debug(level, tun, fmt, args...)                     \
  92 do {                                                            \
  93         if (0)                                                  \
  94                 netdev_printk(level, tun->dev, fmt, ##args);    \
  95 } while (0)
  96 #define DBG1(level, fmt, args...)                               \
  97 do {                                                            \
  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
 106 struct 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
 112 struct tun_file {
 113         atomic_t count;
 114         struct tun_struct *tun;
 115         struct net *net;
 116 };
 117
 118 struct tun_sock;
 119
 120 struct 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
 143 struct tun_sock {
 144         struct sock             sk;
 145         struct tun_struct       *tun;
 146 };
 147
 148 static inline struct tun_sock *tun_sk(struct sock *sk)
 149 {
 150         return container_of(sk, struct tun_sock, sk);
 151 }
 152
 153 static 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
 179 out:
 180         netif_tx_unlock_bh(tun->dev);
 181         return err;
 182 }
 183
 184 static 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
 199 static void tun_detach(struct tun_struct *tun)
 200 {
 201         rtnl_lock();
 202         __tun_detach(tun);
 203         rtnl_unlock();
 204 }
 205
 206 static 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
 216 static struct tun_struct *tun_get(struct file *file)
 217 {
 218         return __tun_get(file->private_data);
 219 }
 220
 221 static 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 */
 230 static 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
 236 static 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
 242 static 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
 302 done:
 303         kfree(addr);
 304         return err;
 305 }
 306
 307 /* Returns: 0 - drop, !=0 - accept */
 308 static 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  */
 331 static 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
 341 static const struct ethtool_ops tun_ethtool_ops;
 342
 343 /* Net device detach from fd. */
 344 static 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
 358 static 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. */
 368 static int tun_net_open(struct net_device *dev)
 369 {
 370         netif_start_queue(dev);
 371         return 0;
 372 }
 373
 374 /* Net device close. */
 375 static int tun_net_close(struct net_device *dev)
 376 {
 377         netif_stop_queue(dev);
 378         return 0;
 379 }
 380
 381 /* Net device start xmit */
 382 static 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
 434 drop:
 435         dev->stats.tx_dropped++;
 436         kfree_skb(skb);
 437         return NETDEV_TX_OK;
 438 }
 439
 440 static 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
 452 static int
 453 tun_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
 461 static 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
 469 static 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
 485 static 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
 497 static 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. */
 513 static 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 */
 548 static 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). */
 581 static 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 */
 609 static 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 */
 687 static 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
 859 static 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 */
 879 static 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
 959 static 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
1007 static 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);
1025 out:
1026         tun_put(tun);
1027         return ret;
1028 }
1029
1030 static 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  */
1044 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1045 {
1046         return -EINVAL;
1047 }
1048
1049 static 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
1056 static 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
1076 static void tun_sock_destruct(struct sock *sk)
1077 {
1078         free_netdev(tun_sk(sk)->tun->dev);
1079 }
1080
1081 static 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
1089 static 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
1106 static 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 */
1114 static const struct proto_ops tun_socket_ops = {
1115         .sendmsg = tun_sendmsg,
1116         .recvmsg = tun_recvmsg,
1117         .release = tun_release,
1118 };
1119
1120 static struct proto tun_proto = {
1121         .name           = "tun",
1122         .owner          = THIS_MODULE,
1123         .obj_size       = sizeof(struct tun_sock),
1124 };
1125
1126 static 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
1147 static 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
1154 static 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
1161 static 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
1168 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1169 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1170 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1171
1172 static 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
1318 static 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. */
1332 static 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
1369 static 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
1568 unlock:
1569         rtnl_unlock();
1570         if (tun)
1571                 tun_put(tun);
1572         return ret;
1573 }
1574
1575 static 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
1582 static 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
1610 static 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;
1631 out:
1632         tun_put(tun);
1633         return ret;
1634 }
1635
1636 static 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
1652 static 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
1684 static 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
1701 static 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
1710 static 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
1725 static 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
1742 static 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
1752 static 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
1760 static 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
1769 static 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;
1788 err_misc:
1789         rtnl_link_unregister(&tun_link_ops);
1790 err_linkops:
1791         return ret;
1792 }
1793
1794 static 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. */
1804 struct 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 }
1815 EXPORT_SYMBOL_GPL(tun_get_socket);
1816
1817 module_init(tun_init);
1818 module_exit(tun_cleanup);
1819 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1820 MODULE_AUTHOR(DRV_COPYRIGHT);
1821 MODULE_LICENSE("GPL");
1822 MODULE_ALIAS_MISCDEV(TUN_MINOR);
1823 MODULE_ALIAS("devname:net/tun");