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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 /* This is like a cut-down ethtool ops, except done via tun fd so no
 752  * privs required. */
 753 static int set_offload(struct net_device *dev, unsigned long arg)
 754 {
 755         unsigned int old_features, features;
 756
 757         old_features = dev->features;
 758         /* Unset features, set them as we chew on the arg. */
 759         features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
 760                                     |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6));
 761
 762         if (arg & TUN_F_CSUM) {
 763                 features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
 764                 arg &= ~TUN_F_CSUM;
 765
 766                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
 767                         if (arg & TUN_F_TSO_ECN) {
 768                                 features |= NETIF_F_TSO_ECN;
 769                                 arg &= ~TUN_F_TSO_ECN;
 770                         }
 771                         if (arg & TUN_F_TSO4)
 772                                 features |= NETIF_F_TSO;
 773                         if (arg & TUN_F_TSO6)
 774                                 features |= NETIF_F_TSO6;
 775                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
 776                 }
 777         }
 778
 779         /* This gives the user a way to test for new features in future by
 780          * trying to set them. */
 781         if (arg)
 782                 return -EINVAL;
 783
 784         dev->features = features;
 785         if (old_features != dev->features)
 786                 netdev_features_change(dev);
 787
 788         return 0;
 789 }
 790
 791 static int tun_chr_ioctl(struct inode *inode, struct file *file,
 792                          unsigned int cmd, unsigned long arg)
 793 {
 794         struct tun_struct *tun = file->private_data;
 795         void __user* argp = (void __user*)arg;
 796         struct ifreq ifr;
 797         int ret;
 798         DECLARE_MAC_BUF(mac);
 799
 800         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
 801                 if (copy_from_user(&ifr, argp, sizeof ifr))
 802                         return -EFAULT;
 803
 804         if (cmd == TUNSETIFF && !tun) {
 805                 int err;
 806
 807                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
 808
 809                 rtnl_lock();
 810                 err = tun_set_iff(current->nsproxy->net_ns, file, &ifr);
 811                 rtnl_unlock();
 812
 813                 if (err)
 814                         return err;
 815
 816                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
 817                         return -EFAULT;
 818                 return 0;
 819         }
 820
 821         if (cmd == TUNGETFEATURES) {
 822                 /* Currently this just means: "what IFF flags are valid?".
 823                  * This is needed because we never checked for invalid flags on
 824                  * TUNSETIFF. */
 825                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
 826                                 IFF_VNET_HDR,
 827                                 (unsigned int __user*)argp);
 828         }
 829
 830         if (!tun)
 831                 return -EBADFD;
 832
 833         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
 834
 835         switch (cmd) {
 836         case TUNSETNOCSUM:
 837                 /* Disable/Enable checksum */
 838                 if (arg)
 839                         tun->flags |= TUN_NOCHECKSUM;
 840                 else
 841                         tun->flags &= ~TUN_NOCHECKSUM;
 842
 843                 DBG(KERN_INFO "%s: checksum %s\n",
 844                     tun->dev->name, arg ? "disabled" : "enabled");
 845                 break;
 846
 847         case TUNSETPERSIST:
 848                 /* Disable/Enable persist mode */
 849                 if (arg)
 850                         tun->flags |= TUN_PERSIST;
 851                 else
 852                         tun->flags &= ~TUN_PERSIST;
 853
 854                 DBG(KERN_INFO "%s: persist %s\n",
 855                     tun->dev->name, arg ? "enabled" : "disabled");
 856                 break;
 857
 858         case TUNSETOWNER:
 859                 /* Set owner of the device */
 860                 tun->owner = (uid_t) arg;
 861
 862                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
 863                 break;
 864
 865         case TUNSETGROUP:
 866                 /* Set group of the device */
 867                 tun->group= (gid_t) arg;
 868
 869                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
 870                 break;
 871
 872         case TUNSETLINK:
 873                 /* Only allow setting the type when the interface is down */
 874                 rtnl_lock();
 875                 if (tun->dev->flags & IFF_UP) {
 876                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
 877                                 tun->dev->name);
 878                         ret = -EBUSY;
 879                 } else {
 880                         tun->dev->type = (int) arg;
 881                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
 882                         ret = 0;
 883                 }
 884                 rtnl_unlock();
 885                 return ret;
 886
 887 #ifdef TUN_DEBUG
 888         case TUNSETDEBUG:
 889                 tun->debug = arg;
 890                 break;
 891 #endif
 892         case TUNSETOFFLOAD:
 893                 rtnl_lock();
 894                 ret = set_offload(tun->dev, arg);
 895                 rtnl_unlock();
 896                 return ret;
 897
 898         case TUNSETTXFILTER:
 899                 /* Can be set only for TAPs */
 900                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
 901                         return -EINVAL;
 902                 rtnl_lock();
 903                 ret = update_filter(&tun->txflt, (void *) __user arg);
 904                 rtnl_unlock();
 905                 return ret;
 906
 907         case SIOCGIFHWADDR:
 908                 /* Get hw addres */
 909                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
 910                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
 911                 if (copy_to_user(argp, &ifr, sizeof ifr))
 912                         return -EFAULT;
 913                 return 0;
 914
 915         case SIOCSIFHWADDR:
 916                 /* Set hw address */
 917                 DBG(KERN_DEBUG "%s: set hw address: %s\n",
 918                         tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
 919
 920                 rtnl_lock();
 921                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
 922                 rtnl_unlock();
 923                 return ret;
 924
 925         default:
 926                 return -EINVAL;
 927         };
 928
 929         return 0;
 930 }
 931
 932 static int tun_chr_fasync(int fd, struct file *file, int on)
 933 {
 934         struct tun_struct *tun = file->private_data;
 935         int ret;
 936
 937         if (!tun)
 938                 return -EBADFD;
 939
 940         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
 941
 942         lock_kernel();
 943         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
 944                 goto out;
 945
 946         if (on) {
 947                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
 948                 if (ret)
 949                         goto out;
 950                 tun->flags |= TUN_FASYNC;
 951         } else
 952                 tun->flags &= ~TUN_FASYNC;
 953         ret = 0;
 954 out:
 955         unlock_kernel();
 956         return ret;
 957 }
 958
 959 static int tun_chr_open(struct inode *inode, struct file * file)
 960 {
 961         cycle_kernel_lock();
 962         DBG1(KERN_INFO "tunX: tun_chr_open\n");
 963         file->private_data = NULL;
 964         return 0;
 965 }
 966
 967 static int tun_chr_close(struct inode *inode, struct file *file)
 968 {
 969         struct tun_struct *tun = file->private_data;
 970
 971         if (!tun)
 972                 return 0;
 973
 974         DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
 975
 976         tun_chr_fasync(-1, file, 0);
 977
 978         rtnl_lock();
 979
 980         /* Detach from net device */
 981         file->private_data = NULL;
 982         tun->attached = 0;
 983         put_net(dev_net(tun->dev));
 984
 985         /* Drop read queue */
 986         skb_queue_purge(&tun->readq);
 987
 988         if (!(tun->flags & TUN_PERSIST)) {
 989                 list_del(&tun->list);
 990                 unregister_netdevice(tun->dev);
 991         }
 992
 993         rtnl_unlock();
 994
 995         return 0;
 996 }
 997
 998 static const struct file_operations tun_fops = {
 999         .owner  = THIS_MODULE,
1000         .llseek = no_llseek,
1001         .read  = do_sync_read,
1002         .aio_read  = tun_chr_aio_read,
1003         .write = do_sync_write,
1004         .aio_write = tun_chr_aio_write,
1005         .poll   = tun_chr_poll,
1006         .ioctl  = tun_chr_ioctl,
1007         .open   = tun_chr_open,
1008         .release = tun_chr_close,
1009         .fasync = tun_chr_fasync
1010 };
1011
1012 static struct miscdevice tun_miscdev = {
1013         .minor = TUN_MINOR,
1014         .name = "tun",
1015         .fops = &tun_fops,
1016 };
1017
1018 /* ethtool interface */
1019
1020 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1021 {
1022         cmd->supported          = 0;
1023         cmd->advertising        = 0;
1024         cmd->speed              = SPEED_10;
1025         cmd->duplex             = DUPLEX_FULL;
1026         cmd->port               = PORT_TP;
1027         cmd->phy_address        = 0;
1028         cmd->transceiver        = XCVR_INTERNAL;
1029         cmd->autoneg            = AUTONEG_DISABLE;
1030         cmd->maxtxpkt           = 0;
1031         cmd->maxrxpkt           = 0;
1032         return 0;
1033 }
1034
1035 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1036 {
1037         struct tun_struct *tun = netdev_priv(dev);
1038
1039         strcpy(info->driver, DRV_NAME);
1040         strcpy(info->version, DRV_VERSION);
1041         strcpy(info->fw_version, "N/A");
1042
1043         switch (tun->flags & TUN_TYPE_MASK) {
1044         case TUN_TUN_DEV:
1045                 strcpy(info->bus_info, "tun");
1046                 break;
1047         case TUN_TAP_DEV:
1048                 strcpy(info->bus_info, "tap");
1049                 break;
1050         }
1051 }
1052
1053 static u32 tun_get_msglevel(struct net_device *dev)
1054 {
1055 #ifdef TUN_DEBUG
1056         struct tun_struct *tun = netdev_priv(dev);
1057         return tun->debug;
1058 #else
1059         return -EOPNOTSUPP;
1060 #endif
1061 }
1062
1063 static void tun_set_msglevel(struct net_device *dev, u32 value)
1064 {
1065 #ifdef TUN_DEBUG
1066         struct tun_struct *tun = netdev_priv(dev);
1067         tun->debug = value;
1068 #endif
1069 }
1070
1071 static u32 tun_get_link(struct net_device *dev)
1072 {
1073         struct tun_struct *tun = netdev_priv(dev);
1074         return tun->attached;
1075 }
1076
1077 static u32 tun_get_rx_csum(struct net_device *dev)
1078 {
1079         struct tun_struct *tun = netdev_priv(dev);
1080         return (tun->flags & TUN_NOCHECKSUM) == 0;
1081 }
1082
1083 static int tun_set_rx_csum(struct net_device *dev, u32 data)
1084 {
1085         struct tun_struct *tun = netdev_priv(dev);
1086         if (data)
1087                 tun->flags &= ~TUN_NOCHECKSUM;
1088         else
1089                 tun->flags |= TUN_NOCHECKSUM;
1090         return 0;
1091 }
1092
1093 static const struct ethtool_ops tun_ethtool_ops = {
1094         .get_settings   = tun_get_settings,
1095         .get_drvinfo    = tun_get_drvinfo,
1096         .get_msglevel   = tun_get_msglevel,
1097         .set_msglevel   = tun_set_msglevel,
1098         .get_link       = tun_get_link,
1099         .get_rx_csum    = tun_get_rx_csum,
1100         .set_rx_csum    = tun_set_rx_csum
1101 };
1102
1103 static int tun_init_net(struct net *net)
1104 {
1105         struct tun_net *tn;
1106
1107         tn = kmalloc(sizeof(*tn), GFP_KERNEL);
1108         if (tn == NULL)
1109                 return -ENOMEM;
1110
1111         INIT_LIST_HEAD(&tn->dev_list);
1112
1113         if (net_assign_generic(net, tun_net_id, tn)) {
1114                 kfree(tn);
1115                 return -ENOMEM;
1116         }
1117
1118         return 0;
1119 }
1120
1121 static void tun_exit_net(struct net *net)
1122 {
1123         struct tun_net *tn;
1124         struct tun_struct *tun, *nxt;
1125
1126         tn = net_generic(net, tun_net_id);
1127
1128         rtnl_lock();
1129         list_for_each_entry_safe(tun, nxt, &tn->dev_list, list) {
1130                 DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
1131                 unregister_netdevice(tun->dev);
1132         }
1133         rtnl_unlock();
1134
1135         kfree(tn);
1136 }
1137
1138 static struct pernet_operations tun_net_ops = {
1139         .init = tun_init_net,
1140         .exit = tun_exit_net,
1141 };
1142
1143 static int __init tun_init(void)
1144 {
1145         int ret = 0;
1146
1147         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1148         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
1149
1150         ret = register_pernet_gen_device(&tun_net_id, &tun_net_ops);
1151         if (ret) {
1152                 printk(KERN_ERR "tun: Can't register pernet ops\n");
1153                 goto err_pernet;
1154         }
1155
1156         ret = misc_register(&tun_miscdev);
1157         if (ret) {
1158                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
1159                 goto err_misc;
1160         }
1161         return 0;
1162
1163 err_misc:
1164         unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
1165 err_pernet:
1166         return ret;
1167 }
1168
1169 static void tun_cleanup(void)
1170 {
1171         misc_deregister(&tun_miscdev);
1172         unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
1173 }
1174
1175 module_init(tun_init);
1176 module_exit(tun_cleanup);
1177 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1178 MODULE_AUTHOR(DRV_COPYRIGHT);
1179 MODULE_LICENSE("GPL");
1180 MODULE_ALIAS_MISCDEV(TUN_MINOR);