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   1 /*
   2  *  TUN - Universal TUN/TAP device driver.
   3  *  Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
  16  */
  17
  18 /*
  19  *  Changes:
  20  *
  21  *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
  22  *    Add TUNSETLINK ioctl to set the link encapsulation
  23  *
  24  *  Mark Smith <markzzzsmith@yahoo.com.au>
  25  *    Use random_ether_addr() for tap MAC address.
  26  *
  27  *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
  28  *    Fixes in packet dropping, queue length setting and queue wakeup.
  29  *    Increased default tx queue length.
  30  *    Added ethtool API.
  31  *    Minor cleanups
  32  *
  33  *  Daniel Podlejski <underley@underley.eu.org>
  34  *    Modifications for 2.3.99-pre5 kernel.
  35  */
  36
  37 #define DRV_NAME        "tun"
  38 #define DRV_VERSION     "1.6"
  39 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  40 #define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
  41
  42 #include <linux/module.h>
  43 #include <linux/errno.h>
  44 #include <linux/kernel.h>
  45 #include <linux/major.h>
  46 #include <linux/slab.h>
  47 #include <linux/smp_lock.h>
  48 #include <linux/poll.h>
  49 #include <linux/fcntl.h>
  50 #include <linux/init.h>
  51 #include <linux/skbuff.h>
  52 #include <linux/netdevice.h>
  53 #include <linux/etherdevice.h>
  54 #include <linux/miscdevice.h>
  55 #include <linux/ethtool.h>
  56 #include <linux/rtnetlink.h>
  57 #include <linux/if.h>
  58 #include <linux/if_arp.h>
  59 #include <linux/if_ether.h>
  60 #include <linux/if_tun.h>
  61 #include <linux/crc32.h>
  62 #include <linux/nsproxy.h>
  63 #include <linux/virtio_net.h>
  64 #include <net/net_namespace.h>
  65 #include <net/netns/generic.h>
  66
  67 #include <asm/system.h>
  68 #include <asm/uaccess.h>
  69
  70 /* Uncomment to enable debugging */
  71 /* #define TUN_DEBUG 1 */
  72
  73 #ifdef TUN_DEBUG
  74 static int debug;
  75
  76 #define DBG  if(tun->debug)printk
  77 #define DBG1 if(debug==2)printk
  78 #else
  79 #define DBG( a... )
  80 #define DBG1( a... )
  81 #endif
  82
  83 #define FLT_EXACT_COUNT 8
  84 struct tap_filter {
  85         unsigned int    count;    /* Number of addrs. Zero means disabled */
  86         u32             mask[2];  /* Mask of the hashed addrs */
  87         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
  88 };
  89
  90 struct tun_struct {
  91         struct list_head        list;
  92         unsigned int            flags;
  93         int                     attached;
  94         uid_t                   owner;
  95         gid_t                   group;
  96
  97         wait_queue_head_t       read_wait;
  98         struct sk_buff_head     readq;
  99
 100         struct net_device       *dev;
 101         struct fasync_struct    *fasync;
 102
 103         struct tap_filter       txflt;
 104
 105 #ifdef TUN_DEBUG
 106         int debug;
 107 #endif
 108 };
 109
 110 /* TAP filterting */
 111 static void addr_hash_set(u32 *mask, const u8 *addr)
 112 {
 113         int n = ether_crc(ETH_ALEN, addr) >> 26;
 114         mask[n >> 5] |= (1 << (n & 31));
 115 }
 116
 117 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 118 {
 119         int n = ether_crc(ETH_ALEN, addr) >> 26;
 120         return mask[n >> 5] & (1 << (n & 31));
 121 }
 122
 123 static int update_filter(struct tap_filter *filter, void __user *arg)
 124 {
 125         struct { u8 u[ETH_ALEN]; } *addr;
 126         struct tun_filter uf;
 127         int err, alen, n, nexact;
 128
 129         if (copy_from_user(&uf, arg, sizeof(uf)))
 130                 return -EFAULT;
 131
 132         if (!uf.count) {
 133                 /* Disabled */
 134                 filter->count = 0;
 135                 return 0;
 136         }
 137
 138         alen = ETH_ALEN * uf.count;
 139         addr = kmalloc(alen, GFP_KERNEL);
 140         if (!addr)
 141                 return -ENOMEM;
 142
 143         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 144                 err = -EFAULT;
 145                 goto done;
 146         }
 147
 148         /* The filter is updated without holding any locks. Which is
 149          * perfectly safe. We disable it first and in the worst
 150          * case we'll accept a few undesired packets. */
 151         filter->count = 0;
 152         wmb();
 153
 154         /* Use first set of addresses as an exact filter */
 155         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 156                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 157
 158         nexact = n;
 159
 160         /* The rest is hashed */
 161         memset(filter->mask, 0, sizeof(filter->mask));
 162         for (; n < uf.count; n++)
 163                 addr_hash_set(filter->mask, addr[n].u);
 164
 165         /* For ALLMULTI just set the mask to all ones.
 166          * This overrides the mask populated above. */
 167         if ((uf.flags & TUN_FLT_ALLMULTI))
 168                 memset(filter->mask, ~0, sizeof(filter->mask));
 169
 170         /* Now enable the filter */
 171         wmb();
 172         filter->count = nexact;
 173
 174         /* Return the number of exact filters */
 175         err = nexact;
 176
 177 done:
 178         kfree(addr);
 179         return err;
 180 }
 181
 182 /* Returns: 0 - drop, !=0 - accept */
 183 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 184 {
 185         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 186          * at this point. */
 187         struct ethhdr *eh = (struct ethhdr *) skb->data;
 188         int i;
 189
 190         /* Exact match */
 191         for (i = 0; i < filter->count; i++)
 192                 if (!compare_ether_addr(eh->h_dest, filter->addr[i]))
 193                         return 1;
 194
 195         /* Inexact match (multicast only) */
 196         if (is_multicast_ether_addr(eh->h_dest))
 197                 return addr_hash_test(filter->mask, eh->h_dest);
 198
 199         return 0;
 200 }
 201
 202 /*
 203  * Checks whether the packet is accepted or not.
 204  * Returns: 0 - drop, !=0 - accept
 205  */
 206 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 207 {
 208         if (!filter->count)
 209                 return 1;
 210
 211         return run_filter(filter, skb);
 212 }
 213
 214 /* Network device part of the driver */
 215
 216 static unsigned int tun_net_id;
 217 struct tun_net {
 218         struct list_head dev_list;
 219 };
 220
 221 static const struct ethtool_ops tun_ethtool_ops;
 222
 223 /* Net device open. */
 224 static int tun_net_open(struct net_device *dev)
 225 {
 226         netif_start_queue(dev);
 227         return 0;
 228 }
 229
 230 /* Net device close. */
 231 static int tun_net_close(struct net_device *dev)
 232 {
 233         netif_stop_queue(dev);
 234         return 0;
 235 }
 236
 237 /* Net device start xmit */
 238 static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 239 {
 240         struct tun_struct *tun = netdev_priv(dev);
 241
 242         DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
 243
 244         /* Drop packet if interface is not attached */
 245         if (!tun->attached)
 246                 goto drop;
 247
 248         /* Drop if the filter does not like it.
 249          * This is a noop if the filter is disabled.
 250          * Filter can be enabled only for the TAP devices. */
 251         if (!check_filter(&tun->txflt, skb))
 252                 goto drop;
 253
 254         if (skb_queue_len(&tun->readq) >= dev->tx_queue_len) {
 255                 if (!(tun->flags & TUN_ONE_QUEUE)) {
 256                         /* Normal queueing mode. */
 257                         /* Packet scheduler handles dropping of further packets. */
 258                         netif_stop_queue(dev);
 259
 260                         /* We won't see all dropped packets individually, so overrun
 261                          * error is more appropriate. */
 262                         dev->stats.tx_fifo_errors++;
 263                 } else {
 264                         /* Single queue mode.
 265                          * Driver handles dropping of all packets itself. */
 266                         goto drop;
 267                 }
 268         }
 269
 270         /* Enqueue packet */
 271         skb_queue_tail(&tun->readq, skb);
 272         dev->trans_start = jiffies;
 273
 274         /* Notify and wake up reader process */
 275         if (tun->flags & TUN_FASYNC)
 276                 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
 277         wake_up_interruptible(&tun->read_wait);
 278         return 0;
 279
 280 drop:
 281         dev->stats.tx_dropped++;
 282         kfree_skb(skb);
 283         return 0;
 284 }
 285
 286 static void tun_net_mclist(struct net_device *dev)
 287 {
 288         /*
 289          * This callback is supposed to deal with mc filter in
 290          * _rx_ path and has nothing to do with the _tx_ path.
 291          * In rx path we always accept everything userspace gives us.
 292          */
 293         return;
 294 }
 295
 296 #define MIN_MTU 68
 297 #define MAX_MTU 65535
 298
 299 static int
 300 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 301 {
 302         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 303                 return -EINVAL;
 304         dev->mtu = new_mtu;
 305         return 0;
 306 }
 307
 308 /* Initialize net device. */
 309 static void tun_net_init(struct net_device *dev)
 310 {
 311         struct tun_struct *tun = netdev_priv(dev);
 312
 313         switch (tun->flags & TUN_TYPE_MASK) {
 314         case TUN_TUN_DEV:
 315                 /* Point-to-Point TUN Device */
 316                 dev->hard_header_len = 0;
 317                 dev->addr_len = 0;
 318                 dev->mtu = 1500;
 319                 dev->change_mtu = tun_net_change_mtu;
 320
 321                 /* Zero header length */
 322                 dev->type = ARPHRD_NONE;
 323                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 324                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 325                 break;
 326
 327         case TUN_TAP_DEV:
 328                 /* Ethernet TAP Device */
 329                 ether_setup(dev);
 330                 dev->change_mtu         = tun_net_change_mtu;
 331                 dev->set_multicast_list = tun_net_mclist;
 332
 333                 random_ether_addr(dev->dev_addr);
 334
 335                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 336                 break;
 337         }
 338 }
 339
 340 /* Character device part */
 341
 342 /* Poll */
 343 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
 344 {
 345         struct tun_struct *tun = file->private_data;
 346         unsigned int mask = POLLOUT | POLLWRNORM;
 347
 348         if (!tun)
 349                 return -EBADFD;
 350
 351         DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
 352
 353         poll_wait(file, &tun->read_wait, wait);
 354
 355         if (!skb_queue_empty(&tun->readq))
 356                 mask |= POLLIN | POLLRDNORM;
 357
 358         return mask;
 359 }
 360
 361 /* Get packet from user space buffer */
 362 static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
 363 {
 364         struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
 365         struct sk_buff *skb;
 366         size_t len = count, align = 0;
 367         struct virtio_net_hdr gso = { 0 };
 368
 369         if (!(tun->flags & TUN_NO_PI)) {
 370                 if ((len -= sizeof(pi)) > count)
 371                         return -EINVAL;
 372
 373                 if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
 374                         return -EFAULT;
 375         }
 376
 377         if (tun->flags & TUN_VNET_HDR) {
 378                 if ((len -= sizeof(gso)) > count)
 379                         return -EINVAL;
 380
 381                 if (memcpy_fromiovec((void *)&gso, iv, sizeof(gso)))
 382                         return -EFAULT;
 383
 384                 if (gso.hdr_len > len)
 385                         return -EINVAL;
 386         }
 387
 388         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
 389                 align = NET_IP_ALIGN;
 390                 if (unlikely(len < ETH_HLEN))
 391                         return -EINVAL;
 392         }
 393
 394         if (!(skb = alloc_skb(len + align, GFP_KERNEL))) {
 395                 tun->dev->stats.rx_dropped++;
 396                 return -ENOMEM;
 397         }
 398
 399         if (align)
 400                 skb_reserve(skb, align);
 401         if (memcpy_fromiovec(skb_put(skb, len), iv, len)) {
 402                 tun->dev->stats.rx_dropped++;
 403                 kfree_skb(skb);
 404                 return -EFAULT;
 405         }
 406
 407         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 408                 if (!skb_partial_csum_set(skb, gso.csum_start,
 409                                           gso.csum_offset)) {
 410                         tun->dev->stats.rx_frame_errors++;
 411                         kfree_skb(skb);
 412                         return -EINVAL;
 413                 }
 414         } else if (tun->flags & TUN_NOCHECKSUM)
 415                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 416
 417         switch (tun->flags & TUN_TYPE_MASK) {
 418         case TUN_TUN_DEV:
 419                 if (tun->flags & TUN_NO_PI) {
 420                         switch (skb->data[0] & 0xf0) {
 421                         case 0x40:
 422                                 pi.proto = htons(ETH_P_IP);
 423                                 break;
 424                         case 0x60:
 425                                 pi.proto = htons(ETH_P_IPV6);
 426                                 break;
 427                         default:
 428                                 tun->dev->stats.rx_dropped++;
 429                                 kfree_skb(skb);
 430                                 return -EINVAL;
 431                         }
 432                 }
 433
 434                 skb_reset_mac_header(skb);
 435                 skb->protocol = pi.proto;
 436                 skb->dev = tun->dev;
 437                 break;
 438         case TUN_TAP_DEV:
 439                 skb->protocol = eth_type_trans(skb, tun->dev);
 440                 break;
 441         };
 442
 443         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 444                 pr_debug("GSO!\n");
 445                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 446                 case VIRTIO_NET_HDR_GSO_TCPV4:
 447                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 448                         break;
 449                 case VIRTIO_NET_HDR_GSO_TCPV6:
 450                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 451                         break;
 452                 default:
 453                         tun->dev->stats.rx_frame_errors++;
 454                         kfree_skb(skb);
 455                         return -EINVAL;
 456                 }
 457
 458                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 459                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 460
 461                 skb_shinfo(skb)->gso_size = gso.gso_size;
 462                 if (skb_shinfo(skb)->gso_size == 0) {
 463                         tun->dev->stats.rx_frame_errors++;
 464                         kfree_skb(skb);
 465                         return -EINVAL;
 466                 }
 467
 468                 /* Header must be checked, and gso_segs computed. */
 469                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 470                 skb_shinfo(skb)->gso_segs = 0;
 471         }
 472
 473         netif_rx_ni(skb);
 474         tun->dev->last_rx = jiffies;
 475
 476         tun->dev->stats.rx_packets++;
 477         tun->dev->stats.rx_bytes += len;
 478
 479         return count;
 480 }
 481
 482 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 483                               unsigned long count, loff_t pos)
 484 {
 485         struct tun_struct *tun = iocb->ki_filp->private_data;
 486
 487         if (!tun)
 488                 return -EBADFD;
 489
 490         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 491
 492         return tun_get_user(tun, (struct iovec *) iv, iov_length(iv, count));
 493 }
 494
 495 /* Put packet to the user space buffer */
 496 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
 497                                        struct sk_buff *skb,
 498                                        struct iovec *iv, int len)
 499 {
 500         struct tun_pi pi = { 0, skb->protocol };
 501         ssize_t total = 0;
 502
 503         if (!(tun->flags & TUN_NO_PI)) {
 504                 if ((len -= sizeof(pi)) < 0)
 505                         return -EINVAL;
 506
 507                 if (len < skb->len) {
 508                         /* Packet will be striped */
 509                         pi.flags |= TUN_PKT_STRIP;
 510                 }
 511
 512                 if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
 513                         return -EFAULT;
 514                 total += sizeof(pi);
 515         }
 516
 517         if (tun->flags & TUN_VNET_HDR) {
 518                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
 519                 if ((len -= sizeof(gso)) < 0)
 520                         return -EINVAL;
 521
 522                 if (skb_is_gso(skb)) {
 523                         struct skb_shared_info *sinfo = skb_shinfo(skb);
 524
 525                         /* This is a hint as to how much should be linear. */
 526                         gso.hdr_len = skb_headlen(skb);
 527                         gso.gso_size = sinfo->gso_size;
 528                         if (sinfo->gso_type & SKB_GSO_TCPV4)
 529                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 530                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
 531                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 532                         else
 533                                 BUG();
 534                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 535                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 536                 } else
 537                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 538
 539                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
 540                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 541                         gso.csum_start = skb->csum_start - skb_headroom(skb);
 542                         gso.csum_offset = skb->csum_offset;
 543                 } /* else everything is zero */
 544
 545                 if (unlikely(memcpy_toiovec(iv, (void *)&gso, sizeof(gso))))
 546                         return -EFAULT;
 547                 total += sizeof(gso);
 548         }
 549
 550         len = min_t(int, skb->len, len);
 551
 552         skb_copy_datagram_iovec(skb, 0, iv, len);
 553         total += len;
 554
 555         tun->dev->stats.tx_packets++;
 556         tun->dev->stats.tx_bytes += len;
 557
 558         return total;
 559 }
 560
 561 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 562                             unsigned long count, loff_t pos)
 563 {
 564         struct file *file = iocb->ki_filp;
 565         struct tun_struct *tun = file->private_data;
 566         DECLARE_WAITQUEUE(wait, current);
 567         struct sk_buff *skb;
 568         ssize_t len, ret = 0;
 569
 570         if (!tun)
 571                 return -EBADFD;
 572
 573         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 574
 575         len = iov_length(iv, count);
 576         if (len < 0)
 577                 return -EINVAL;
 578
 579         add_wait_queue(&tun->read_wait, &wait);
 580         while (len) {
 581                 current->state = TASK_INTERRUPTIBLE;
 582
 583                 /* Read frames from the queue */
 584                 if (!(skb=skb_dequeue(&tun->readq))) {
 585                         if (file->f_flags & O_NONBLOCK) {
 586                                 ret = -EAGAIN;
 587                                 break;
 588                         }
 589                         if (signal_pending(current)) {
 590                                 ret = -ERESTARTSYS;
 591                                 break;
 592                         }
 593
 594                         /* Nothing to read, let's sleep */
 595                         schedule();
 596                         continue;
 597                 }
 598                 netif_wake_queue(tun->dev);
 599
 600                 ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
 601                 kfree_skb(skb);
 602                 break;
 603         }
 604
 605         current->state = TASK_RUNNING;
 606         remove_wait_queue(&tun->read_wait, &wait);
 607
 608         return ret;
 609 }
 610
 611 static void tun_setup(struct net_device *dev)
 612 {
 613         struct tun_struct *tun = netdev_priv(dev);
 614
 615         skb_queue_head_init(&tun->readq);
 616         init_waitqueue_head(&tun->read_wait);
 617
 618         tun->owner = -1;
 619         tun->group = -1;
 620
 621         dev->open = tun_net_open;
 622         dev->hard_start_xmit = tun_net_xmit;
 623         dev->stop = tun_net_close;
 624         dev->ethtool_ops = &tun_ethtool_ops;
 625         dev->destructor = free_netdev;
 626         dev->features |= NETIF_F_NETNS_LOCAL;
 627 }
 628
 629 static struct tun_struct *tun_get_by_name(struct tun_net *tn, const char *name)
 630 {
 631         struct tun_struct *tun;
 632
 633         ASSERT_RTNL();
 634         list_for_each_entry(tun, &tn->dev_list, list) {
 635                 if (!strncmp(tun->dev->name, name, IFNAMSIZ))
 636                     return tun;
 637         }
 638
 639         return NULL;
 640 }
 641
 642 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 643 {
 644         struct tun_net *tn;
 645         struct tun_struct *tun;
 646         struct net_device *dev;
 647         int err;
 648
 649         tn = net_generic(net, tun_net_id);
 650         tun = tun_get_by_name(tn, ifr->ifr_name);
 651         if (tun) {
 652                 if (tun->attached)
 653                         return -EBUSY;
 654
 655                 /* Check permissions */
 656                 if (((tun->owner != -1 &&
 657                       current->euid != tun->owner) ||
 658                      (tun->group != -1 &&
 659                       current->egid != tun->group)) &&
 660                      !capable(CAP_NET_ADMIN))
 661                         return -EPERM;
 662         }
 663         else if (__dev_get_by_name(net, ifr->ifr_name))
 664                 return -EINVAL;
 665         else {
 666                 char *name;
 667                 unsigned long flags = 0;
 668
 669                 err = -EINVAL;
 670
 671                 if (!capable(CAP_NET_ADMIN))
 672                         return -EPERM;
 673
 674                 /* Set dev type */
 675                 if (ifr->ifr_flags & IFF_TUN) {
 676                         /* TUN device */
 677                         flags |= TUN_TUN_DEV;
 678                         name = "tun%d";
 679                 } else if (ifr->ifr_flags & IFF_TAP) {
 680                         /* TAP device */
 681                         flags |= TUN_TAP_DEV;
 682                         name = "tap%d";
 683                 } else
 684                         goto failed;
 685
 686                 if (*ifr->ifr_name)
 687                         name = ifr->ifr_name;
 688
 689                 dev = alloc_netdev(sizeof(struct tun_struct), name,
 690                                    tun_setup);
 691                 if (!dev)
 692                         return -ENOMEM;
 693
 694                 dev_net_set(dev, net);
 695                 tun = netdev_priv(dev);
 696                 tun->dev = dev;
 697                 tun->flags = flags;
 698                 tun->txflt.count = 0;
 699
 700                 tun_net_init(dev);
 701
 702                 if (strchr(dev->name, '%')) {
 703                         err = dev_alloc_name(dev, dev->name);
 704                         if (err < 0)
 705                                 goto err_free_dev;
 706                 }
 707
 708                 err = register_netdevice(tun->dev);
 709                 if (err < 0)
 710                         goto err_free_dev;
 711
 712                 list_add(&tun->list, &tn->dev_list);
 713         }
 714
 715         DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
 716
 717         if (ifr->ifr_flags & IFF_NO_PI)
 718                 tun->flags |= TUN_NO_PI;
 719         else
 720                 tun->flags &= ~TUN_NO_PI;
 721
 722         if (ifr->ifr_flags & IFF_ONE_QUEUE)
 723                 tun->flags |= TUN_ONE_QUEUE;
 724         else
 725                 tun->flags &= ~TUN_ONE_QUEUE;
 726
 727         if (ifr->ifr_flags & IFF_VNET_HDR)
 728                 tun->flags |= TUN_VNET_HDR;
 729         else
 730                 tun->flags &= ~TUN_VNET_HDR;
 731
 732         file->private_data = tun;
 733         tun->attached = 1;
 734         get_net(dev_net(tun->dev));
 735
 736         /* Make sure persistent devices do not get stuck in
 737          * xoff state.
 738          */
 739         if (netif_running(tun->dev))
 740                 netif_wake_queue(tun->dev);
 741
 742         strcpy(ifr->ifr_name, tun->dev->name);
 743         return 0;
 744
 745  err_free_dev:
 746         free_netdev(dev);
 747  failed:
 748         return err;
 749 }
 750
 751 static int tun_get_iff(struct net *net, struct file *file, struct ifreq *ifr)
 752 {
 753         struct tun_struct *tun = file->private_data;
 754
 755         if (!tun)
 756                 return -EBADFD;
 757
 758         DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
 759
 760         strcpy(ifr->ifr_name, tun->dev->name);
 761
 762         ifr->ifr_flags = 0;
 763
 764         if (ifr->ifr_flags & TUN_TUN_DEV)
 765                 ifr->ifr_flags |= IFF_TUN;
 766         else
 767                 ifr->ifr_flags |= IFF_TAP;
 768
 769         if (tun->flags & TUN_NO_PI)
 770                 ifr->ifr_flags |= IFF_NO_PI;
 771
 772         if (tun->flags & TUN_ONE_QUEUE)
 773                 ifr->ifr_flags |= IFF_ONE_QUEUE;
 774
 775         if (tun->flags & TUN_VNET_HDR)
 776                 ifr->ifr_flags |= IFF_VNET_HDR;
 777
 778         return 0;
 779 }
 780
 781 /* This is like a cut-down ethtool ops, except done via tun fd so no
 782  * privs required. */
 783 static int set_offload(struct net_device *dev, unsigned long arg)
 784 {
 785         unsigned int old_features, features;
 786
 787         old_features = dev->features;
 788         /* Unset features, set them as we chew on the arg. */
 789         features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
 790                                     |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6));
 791
 792         if (arg & TUN_F_CSUM) {
 793                 features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
 794                 arg &= ~TUN_F_CSUM;
 795
 796                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
 797                         if (arg & TUN_F_TSO_ECN) {
 798                                 features |= NETIF_F_TSO_ECN;
 799                                 arg &= ~TUN_F_TSO_ECN;
 800                         }
 801                         if (arg & TUN_F_TSO4)
 802                                 features |= NETIF_F_TSO;
 803                         if (arg & TUN_F_TSO6)
 804                                 features |= NETIF_F_TSO6;
 805                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
 806                 }
 807         }
 808
 809         /* This gives the user a way to test for new features in future by
 810          * trying to set them. */
 811         if (arg)
 812                 return -EINVAL;
 813
 814         dev->features = features;
 815         if (old_features != dev->features)
 816                 netdev_features_change(dev);
 817
 818         return 0;
 819 }
 820
 821 static int tun_chr_ioctl(struct inode *inode, struct file *file,
 822                          unsigned int cmd, unsigned long arg)
 823 {
 824         struct tun_struct *tun = file->private_data;
 825         void __user* argp = (void __user*)arg;
 826         struct ifreq ifr;
 827         int ret;
 828         DECLARE_MAC_BUF(mac);
 829
 830         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
 831                 if (copy_from_user(&ifr, argp, sizeof ifr))
 832                         return -EFAULT;
 833
 834         if (cmd == TUNSETIFF && !tun) {
 835                 int err;
 836
 837                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
 838
 839                 rtnl_lock();
 840                 err = tun_set_iff(current->nsproxy->net_ns, file, &ifr);
 841                 rtnl_unlock();
 842
 843                 if (err)
 844                         return err;
 845
 846                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
 847                         return -EFAULT;
 848                 return 0;
 849         }
 850
 851         if (cmd == TUNGETFEATURES) {
 852                 /* Currently this just means: "what IFF flags are valid?".
 853                  * This is needed because we never checked for invalid flags on
 854                  * TUNSETIFF. */
 855                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
 856                                 IFF_VNET_HDR,
 857                                 (unsigned int __user*)argp);
 858         }
 859
 860         if (!tun)
 861                 return -EBADFD;
 862
 863         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
 864
 865         switch (cmd) {
 866         case TUNGETIFF:
 867                 ret = tun_get_iff(current->nsproxy->net_ns, file, &ifr);
 868                 if (ret)
 869                         return ret;
 870
 871                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
 872                         return -EFAULT;
 873                 break;
 874
 875         case TUNSETNOCSUM:
 876                 /* Disable/Enable checksum */
 877                 if (arg)
 878                         tun->flags |= TUN_NOCHECKSUM;
 879                 else
 880                         tun->flags &= ~TUN_NOCHECKSUM;
 881
 882                 DBG(KERN_INFO "%s: checksum %s\n",
 883                     tun->dev->name, arg ? "disabled" : "enabled");
 884                 break;
 885
 886         case TUNSETPERSIST:
 887                 /* Disable/Enable persist mode */
 888                 if (arg)
 889                         tun->flags |= TUN_PERSIST;
 890                 else
 891                         tun->flags &= ~TUN_PERSIST;
 892
 893                 DBG(KERN_INFO "%s: persist %s\n",
 894                     tun->dev->name, arg ? "enabled" : "disabled");
 895                 break;
 896
 897         case TUNSETOWNER:
 898                 /* Set owner of the device */
 899                 tun->owner = (uid_t) arg;
 900
 901                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
 902                 break;
 903
 904         case TUNSETGROUP:
 905                 /* Set group of the device */
 906                 tun->group= (gid_t) arg;
 907
 908                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
 909                 break;
 910
 911         case TUNSETLINK:
 912                 /* Only allow setting the type when the interface is down */
 913                 rtnl_lock();
 914                 if (tun->dev->flags & IFF_UP) {
 915                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
 916                                 tun->dev->name);
 917                         ret = -EBUSY;
 918                 } else {
 919                         tun->dev->type = (int) arg;
 920                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
 921                         ret = 0;
 922                 }
 923                 rtnl_unlock();
 924                 return ret;
 925
 926 #ifdef TUN_DEBUG
 927         case TUNSETDEBUG:
 928                 tun->debug = arg;
 929                 break;
 930 #endif
 931         case TUNSETOFFLOAD:
 932                 rtnl_lock();
 933                 ret = set_offload(tun->dev, arg);
 934                 rtnl_unlock();
 935                 return ret;
 936
 937         case TUNSETTXFILTER:
 938                 /* Can be set only for TAPs */
 939                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
 940                         return -EINVAL;
 941                 rtnl_lock();
 942                 ret = update_filter(&tun->txflt, (void __user *)arg);
 943                 rtnl_unlock();
 944                 return ret;
 945
 946         case SIOCGIFHWADDR:
 947                 /* Get hw addres */
 948                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
 949                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
 950                 if (copy_to_user(argp, &ifr, sizeof ifr))
 951                         return -EFAULT;
 952                 return 0;
 953
 954         case SIOCSIFHWADDR:
 955                 /* Set hw address */
 956                 DBG(KERN_DEBUG "%s: set hw address: %s\n",
 957                         tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
 958
 959                 rtnl_lock();
 960                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
 961                 rtnl_unlock();
 962                 return ret;
 963
 964         default:
 965                 return -EINVAL;
 966         };
 967
 968         return 0;
 969 }
 970
 971 static int tun_chr_fasync(int fd, struct file *file, int on)
 972 {
 973         struct tun_struct *tun = file->private_data;
 974         int ret;
 975
 976         if (!tun)
 977                 return -EBADFD;
 978
 979         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
 980
 981         lock_kernel();
 982         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
 983                 goto out;
 984
 985         if (on) {
 986                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
 987                 if (ret)
 988                         goto out;
 989                 tun->flags |= TUN_FASYNC;
 990         } else
 991                 tun->flags &= ~TUN_FASYNC;
 992         ret = 0;
 993 out:
 994         unlock_kernel();
 995         return ret;
 996 }
 997
 998 static int tun_chr_open(struct inode *inode, struct file * file)
 999 {
1000         cycle_kernel_lock();
1001         DBG1(KERN_INFO "tunX: tun_chr_open\n");
1002         file->private_data = NULL;
1003         return 0;
1004 }
1005
1006 static int tun_chr_close(struct inode *inode, struct file *file)
1007 {
1008         struct tun_struct *tun = file->private_data;
1009
1010         if (!tun)
1011                 return 0;
1012
1013         DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
1014
1015         tun_chr_fasync(-1, file, 0);
1016
1017         rtnl_lock();
1018
1019         /* Detach from net device */
1020         file->private_data = NULL;
1021         tun->attached = 0;
1022         put_net(dev_net(tun->dev));
1023
1024         /* Drop read queue */
1025         skb_queue_purge(&tun->readq);
1026
1027         if (!(tun->flags & TUN_PERSIST)) {
1028                 list_del(&tun->list);
1029                 unregister_netdevice(tun->dev);
1030         }
1031
1032         rtnl_unlock();
1033
1034         return 0;
1035 }
1036
1037 static const struct file_operations tun_fops = {
1038         .owner  = THIS_MODULE,
1039         .llseek = no_llseek,
1040         .read  = do_sync_read,
1041         .aio_read  = tun_chr_aio_read,
1042         .write = do_sync_write,
1043         .aio_write = tun_chr_aio_write,
1044         .poll   = tun_chr_poll,
1045         .ioctl  = tun_chr_ioctl,
1046         .open   = tun_chr_open,
1047         .release = tun_chr_close,
1048         .fasync = tun_chr_fasync
1049 };
1050
1051 static struct miscdevice tun_miscdev = {
1052         .minor = TUN_MINOR,
1053         .name = "tun",
1054         .fops = &tun_fops,
1055 };
1056
1057 /* ethtool interface */
1058
1059 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1060 {
1061         cmd->supported          = 0;
1062         cmd->advertising        = 0;
1063         cmd->speed              = SPEED_10;
1064         cmd->duplex             = DUPLEX_FULL;
1065         cmd->port               = PORT_TP;
1066         cmd->phy_address        = 0;
1067         cmd->transceiver        = XCVR_INTERNAL;
1068         cmd->autoneg            = AUTONEG_DISABLE;
1069         cmd->maxtxpkt           = 0;
1070         cmd->maxrxpkt           = 0;
1071         return 0;
1072 }
1073
1074 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1075 {
1076         struct tun_struct *tun = netdev_priv(dev);
1077
1078         strcpy(info->driver, DRV_NAME);
1079         strcpy(info->version, DRV_VERSION);
1080         strcpy(info->fw_version, "N/A");
1081
1082         switch (tun->flags & TUN_TYPE_MASK) {
1083         case TUN_TUN_DEV:
1084                 strcpy(info->bus_info, "tun");
1085                 break;
1086         case TUN_TAP_DEV:
1087                 strcpy(info->bus_info, "tap");
1088                 break;
1089         }
1090 }
1091
1092 static u32 tun_get_msglevel(struct net_device *dev)
1093 {
1094 #ifdef TUN_DEBUG
1095         struct tun_struct *tun = netdev_priv(dev);
1096         return tun->debug;
1097 #else
1098         return -EOPNOTSUPP;
1099 #endif
1100 }
1101
1102 static void tun_set_msglevel(struct net_device *dev, u32 value)
1103 {
1104 #ifdef TUN_DEBUG
1105         struct tun_struct *tun = netdev_priv(dev);
1106         tun->debug = value;
1107 #endif
1108 }
1109
1110 static u32 tun_get_link(struct net_device *dev)
1111 {
1112         struct tun_struct *tun = netdev_priv(dev);
1113         return tun->attached;
1114 }
1115
1116 static u32 tun_get_rx_csum(struct net_device *dev)
1117 {
1118         struct tun_struct *tun = netdev_priv(dev);
1119         return (tun->flags & TUN_NOCHECKSUM) == 0;
1120 }
1121
1122 static int tun_set_rx_csum(struct net_device *dev, u32 data)
1123 {
1124         struct tun_struct *tun = netdev_priv(dev);
1125         if (data)
1126                 tun->flags &= ~TUN_NOCHECKSUM;
1127         else
1128                 tun->flags |= TUN_NOCHECKSUM;
1129         return 0;
1130 }
1131
1132 static const struct ethtool_ops tun_ethtool_ops = {
1133         .get_settings   = tun_get_settings,
1134         .get_drvinfo    = tun_get_drvinfo,
1135         .get_msglevel   = tun_get_msglevel,
1136         .set_msglevel   = tun_set_msglevel,
1137         .get_link       = tun_get_link,
1138         .get_rx_csum    = tun_get_rx_csum,
1139         .set_rx_csum    = tun_set_rx_csum
1140 };
1141
1142 static int tun_init_net(struct net *net)
1143 {
1144         struct tun_net *tn;
1145
1146         tn = kmalloc(sizeof(*tn), GFP_KERNEL);
1147         if (tn == NULL)
1148                 return -ENOMEM;
1149
1150         INIT_LIST_HEAD(&tn->dev_list);
1151
1152         if (net_assign_generic(net, tun_net_id, tn)) {
1153                 kfree(tn);
1154                 return -ENOMEM;
1155         }
1156
1157         return 0;
1158 }
1159
1160 static void tun_exit_net(struct net *net)
1161 {
1162         struct tun_net *tn;
1163         struct tun_struct *tun, *nxt;
1164
1165         tn = net_generic(net, tun_net_id);
1166
1167         rtnl_lock();
1168         list_for_each_entry_safe(tun, nxt, &tn->dev_list, list) {
1169                 DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
1170                 unregister_netdevice(tun->dev);
1171         }
1172         rtnl_unlock();
1173
1174         kfree(tn);
1175 }
1176
1177 static struct pernet_operations tun_net_ops = {
1178         .init = tun_init_net,
1179         .exit = tun_exit_net,
1180 };
1181
1182 static int __init tun_init(void)
1183 {
1184         int ret = 0;
1185
1186         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1187         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
1188
1189         ret = register_pernet_gen_device(&tun_net_id, &tun_net_ops);
1190         if (ret) {
1191                 printk(KERN_ERR "tun: Can't register pernet ops\n");
1192                 goto err_pernet;
1193         }
1194
1195         ret = misc_register(&tun_miscdev);
1196         if (ret) {
1197                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
1198                 goto err_misc;
1199         }
1200         return 0;
1201
1202 err_misc:
1203         unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
1204 err_pernet:
1205         return ret;
1206 }
1207
1208 static void tun_cleanup(void)
1209 {
1210         misc_deregister(&tun_miscdev);
1211         unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
1212 }
1213
1214 module_init(tun_init);
1215 module_exit(tun_cleanup);
1216 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1217 MODULE_AUTHOR(DRV_COPYRIGHT);
1218 MODULE_LICENSE("GPL");
1219 MODULE_ALIAS_MISCDEV(TUN_MINOR);