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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 /* prepad is the amount to reserve at front.  len is length after that.
 362  * linear is a hint as to how much to copy (usually headers). */
 363 static struct sk_buff *tun_alloc_skb(size_t prepad, size_t len, size_t linear,
 364                                      gfp_t gfp)
 365 {
 366         struct sk_buff *skb;
 367         unsigned int i;
 368
 369         skb = alloc_skb(prepad + len, gfp|__GFP_NOWARN);
 370         if (skb) {
 371                 skb_reserve(skb, prepad);
 372                 skb_put(skb, len);
 373                 return skb;
 374         }
 375
 376         /* Under a page?  Don't bother with paged skb. */
 377         if (prepad + len < PAGE_SIZE)
 378                 return NULL;
 379
 380         /* Start with a normal skb, and add pages. */
 381         skb = alloc_skb(prepad + linear, gfp);
 382         if (!skb)
 383                 return NULL;
 384
 385         skb_reserve(skb, prepad);
 386         skb_put(skb, linear);
 387
 388         len -= linear;
 389
 390         for (i = 0; i < MAX_SKB_FRAGS; i++) {
 391                 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
 392
 393                 f->page = alloc_page(gfp|__GFP_ZERO);
 394                 if (!f->page)
 395                         break;
 396
 397                 f->page_offset = 0;
 398                 f->size = PAGE_SIZE;
 399
 400                 skb->data_len += PAGE_SIZE;
 401                 skb->len += PAGE_SIZE;
 402                 skb->truesize += PAGE_SIZE;
 403                 skb_shinfo(skb)->nr_frags++;
 404
 405                 if (len < PAGE_SIZE) {
 406                         len = 0;
 407                         break;
 408                 }
 409                 len -= PAGE_SIZE;
 410         }
 411
 412         /* Too large, or alloc fail? */
 413         if (unlikely(len)) {
 414                 kfree_skb(skb);
 415                 skb = NULL;
 416         }
 417
 418         return skb;
 419 }
 420
 421 /* Get packet from user space buffer */
 422 static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
 423 {
 424         struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
 425         struct sk_buff *skb;
 426         size_t len = count, align = 0;
 427         struct virtio_net_hdr gso = { 0 };
 428
 429         if (!(tun->flags & TUN_NO_PI)) {
 430                 if ((len -= sizeof(pi)) > count)
 431                         return -EINVAL;
 432
 433                 if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
 434                         return -EFAULT;
 435         }
 436
 437         if (tun->flags & TUN_VNET_HDR) {
 438                 if ((len -= sizeof(gso)) > count)
 439                         return -EINVAL;
 440
 441                 if (memcpy_fromiovec((void *)&gso, iv, sizeof(gso)))
 442                         return -EFAULT;
 443
 444                 if (gso.hdr_len > len)
 445                         return -EINVAL;
 446         }
 447
 448         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
 449                 align = NET_IP_ALIGN;
 450                 if (unlikely(len < ETH_HLEN))
 451                         return -EINVAL;
 452         }
 453
 454         if (!(skb = tun_alloc_skb(align, len, gso.hdr_len, GFP_KERNEL))) {
 455                 tun->dev->stats.rx_dropped++;
 456                 return -ENOMEM;
 457         }
 458
 459         if (skb_copy_datagram_from_iovec(skb, 0, iv, len)) {
 460                 tun->dev->stats.rx_dropped++;
 461                 kfree_skb(skb);
 462                 return -EFAULT;
 463         }
 464
 465         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 466                 if (!skb_partial_csum_set(skb, gso.csum_start,
 467                                           gso.csum_offset)) {
 468                         tun->dev->stats.rx_frame_errors++;
 469                         kfree_skb(skb);
 470                         return -EINVAL;
 471                 }
 472         } else if (tun->flags & TUN_NOCHECKSUM)
 473                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 474
 475         switch (tun->flags & TUN_TYPE_MASK) {
 476         case TUN_TUN_DEV:
 477                 if (tun->flags & TUN_NO_PI) {
 478                         switch (skb->data[0] & 0xf0) {
 479                         case 0x40:
 480                                 pi.proto = htons(ETH_P_IP);
 481                                 break;
 482                         case 0x60:
 483                                 pi.proto = htons(ETH_P_IPV6);
 484                                 break;
 485                         default:
 486                                 tun->dev->stats.rx_dropped++;
 487                                 kfree_skb(skb);
 488                                 return -EINVAL;
 489                         }
 490                 }
 491
 492                 skb_reset_mac_header(skb);
 493                 skb->protocol = pi.proto;
 494                 skb->dev = tun->dev;
 495                 break;
 496         case TUN_TAP_DEV:
 497                 skb->protocol = eth_type_trans(skb, tun->dev);
 498                 break;
 499         };
 500
 501         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 502                 pr_debug("GSO!\n");
 503                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 504                 case VIRTIO_NET_HDR_GSO_TCPV4:
 505                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 506                         break;
 507                 case VIRTIO_NET_HDR_GSO_TCPV6:
 508                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 509                         break;
 510                 default:
 511                         tun->dev->stats.rx_frame_errors++;
 512                         kfree_skb(skb);
 513                         return -EINVAL;
 514                 }
 515
 516                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 517                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 518
 519                 skb_shinfo(skb)->gso_size = gso.gso_size;
 520                 if (skb_shinfo(skb)->gso_size == 0) {
 521                         tun->dev->stats.rx_frame_errors++;
 522                         kfree_skb(skb);
 523                         return -EINVAL;
 524                 }
 525
 526                 /* Header must be checked, and gso_segs computed. */
 527                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 528                 skb_shinfo(skb)->gso_segs = 0;
 529         }
 530
 531         netif_rx_ni(skb);
 532         tun->dev->last_rx = jiffies;
 533
 534         tun->dev->stats.rx_packets++;
 535         tun->dev->stats.rx_bytes += len;
 536
 537         return count;
 538 }
 539
 540 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 541                               unsigned long count, loff_t pos)
 542 {
 543         struct tun_struct *tun = iocb->ki_filp->private_data;
 544
 545         if (!tun)
 546                 return -EBADFD;
 547
 548         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 549
 550         return tun_get_user(tun, (struct iovec *) iv, iov_length(iv, count));
 551 }
 552
 553 /* Put packet to the user space buffer */
 554 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
 555                                        struct sk_buff *skb,
 556                                        struct iovec *iv, int len)
 557 {
 558         struct tun_pi pi = { 0, skb->protocol };
 559         ssize_t total = 0;
 560
 561         if (!(tun->flags & TUN_NO_PI)) {
 562                 if ((len -= sizeof(pi)) < 0)
 563                         return -EINVAL;
 564
 565                 if (len < skb->len) {
 566                         /* Packet will be striped */
 567                         pi.flags |= TUN_PKT_STRIP;
 568                 }
 569
 570                 if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
 571                         return -EFAULT;
 572                 total += sizeof(pi);
 573         }
 574
 575         if (tun->flags & TUN_VNET_HDR) {
 576                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
 577                 if ((len -= sizeof(gso)) < 0)
 578                         return -EINVAL;
 579
 580                 if (skb_is_gso(skb)) {
 581                         struct skb_shared_info *sinfo = skb_shinfo(skb);
 582
 583                         /* This is a hint as to how much should be linear. */
 584                         gso.hdr_len = skb_headlen(skb);
 585                         gso.gso_size = sinfo->gso_size;
 586                         if (sinfo->gso_type & SKB_GSO_TCPV4)
 587                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 588                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
 589                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 590                         else
 591                                 BUG();
 592                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 593                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 594                 } else
 595                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 596
 597                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
 598                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 599                         gso.csum_start = skb->csum_start - skb_headroom(skb);
 600                         gso.csum_offset = skb->csum_offset;
 601                 } /* else everything is zero */
 602
 603                 if (unlikely(memcpy_toiovec(iv, (void *)&gso, sizeof(gso))))
 604                         return -EFAULT;
 605                 total += sizeof(gso);
 606         }
 607
 608         len = min_t(int, skb->len, len);
 609
 610         skb_copy_datagram_iovec(skb, 0, iv, len);
 611         total += len;
 612
 613         tun->dev->stats.tx_packets++;
 614         tun->dev->stats.tx_bytes += len;
 615
 616         return total;
 617 }
 618
 619 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 620                             unsigned long count, loff_t pos)
 621 {
 622         struct file *file = iocb->ki_filp;
 623         struct tun_struct *tun = file->private_data;
 624         DECLARE_WAITQUEUE(wait, current);
 625         struct sk_buff *skb;
 626         ssize_t len, ret = 0;
 627
 628         if (!tun)
 629                 return -EBADFD;
 630
 631         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 632
 633         len = iov_length(iv, count);
 634         if (len < 0)
 635                 return -EINVAL;
 636
 637         add_wait_queue(&tun->read_wait, &wait);
 638         while (len) {
 639                 current->state = TASK_INTERRUPTIBLE;
 640
 641                 /* Read frames from the queue */
 642                 if (!(skb=skb_dequeue(&tun->readq))) {
 643                         if (file->f_flags & O_NONBLOCK) {
 644                                 ret = -EAGAIN;
 645                                 break;
 646                         }
 647                         if (signal_pending(current)) {
 648                                 ret = -ERESTARTSYS;
 649                                 break;
 650                         }
 651
 652                         /* Nothing to read, let's sleep */
 653                         schedule();
 654                         continue;
 655                 }
 656                 netif_wake_queue(tun->dev);
 657
 658                 ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
 659                 kfree_skb(skb);
 660                 break;
 661         }
 662
 663         current->state = TASK_RUNNING;
 664         remove_wait_queue(&tun->read_wait, &wait);
 665
 666         return ret;
 667 }
 668
 669 static void tun_setup(struct net_device *dev)
 670 {
 671         struct tun_struct *tun = netdev_priv(dev);
 672
 673         skb_queue_head_init(&tun->readq);
 674         init_waitqueue_head(&tun->read_wait);
 675
 676         tun->owner = -1;
 677         tun->group = -1;
 678
 679         dev->open = tun_net_open;
 680         dev->hard_start_xmit = tun_net_xmit;
 681         dev->stop = tun_net_close;
 682         dev->ethtool_ops = &tun_ethtool_ops;
 683         dev->destructor = free_netdev;
 684         dev->features |= NETIF_F_NETNS_LOCAL;
 685 }
 686
 687 static struct tun_struct *tun_get_by_name(struct tun_net *tn, const char *name)
 688 {
 689         struct tun_struct *tun;
 690
 691         ASSERT_RTNL();
 692         list_for_each_entry(tun, &tn->dev_list, list) {
 693                 if (!strncmp(tun->dev->name, name, IFNAMSIZ))
 694                     return tun;
 695         }
 696
 697         return NULL;
 698 }
 699
 700 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 701 {
 702         struct tun_net *tn;
 703         struct tun_struct *tun;
 704         struct net_device *dev;
 705         int err;
 706
 707         tn = net_generic(net, tun_net_id);
 708         tun = tun_get_by_name(tn, ifr->ifr_name);
 709         if (tun) {
 710                 if (tun->attached)
 711                         return -EBUSY;
 712
 713                 /* Check permissions */
 714                 if (((tun->owner != -1 &&
 715                       current->euid != tun->owner) ||
 716                      (tun->group != -1 &&
 717                       current->egid != tun->group)) &&
 718                      !capable(CAP_NET_ADMIN))
 719                         return -EPERM;
 720         }
 721         else if (__dev_get_by_name(net, ifr->ifr_name))
 722                 return -EINVAL;
 723         else {
 724                 char *name;
 725                 unsigned long flags = 0;
 726
 727                 err = -EINVAL;
 728
 729                 if (!capable(CAP_NET_ADMIN))
 730                         return -EPERM;
 731
 732                 /* Set dev type */
 733                 if (ifr->ifr_flags & IFF_TUN) {
 734                         /* TUN device */
 735                         flags |= TUN_TUN_DEV;
 736                         name = "tun%d";
 737                 } else if (ifr->ifr_flags & IFF_TAP) {
 738                         /* TAP device */
 739                         flags |= TUN_TAP_DEV;
 740                         name = "tap%d";
 741                 } else
 742                         goto failed;
 743
 744                 if (*ifr->ifr_name)
 745                         name = ifr->ifr_name;
 746
 747                 dev = alloc_netdev(sizeof(struct tun_struct), name,
 748                                    tun_setup);
 749                 if (!dev)
 750                         return -ENOMEM;
 751
 752                 dev_net_set(dev, net);
 753                 tun = netdev_priv(dev);
 754                 tun->dev = dev;
 755                 tun->flags = flags;
 756                 tun->txflt.count = 0;
 757
 758                 tun_net_init(dev);
 759
 760                 if (strchr(dev->name, '%')) {
 761                         err = dev_alloc_name(dev, dev->name);
 762                         if (err < 0)
 763                                 goto err_free_dev;
 764                 }
 765
 766                 err = register_netdevice(tun->dev);
 767                 if (err < 0)
 768                         goto err_free_dev;
 769
 770                 list_add(&tun->list, &tn->dev_list);
 771         }
 772
 773         DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
 774
 775         if (ifr->ifr_flags & IFF_NO_PI)
 776                 tun->flags |= TUN_NO_PI;
 777         else
 778                 tun->flags &= ~TUN_NO_PI;
 779
 780         if (ifr->ifr_flags & IFF_ONE_QUEUE)
 781                 tun->flags |= TUN_ONE_QUEUE;
 782         else
 783                 tun->flags &= ~TUN_ONE_QUEUE;
 784
 785         if (ifr->ifr_flags & IFF_VNET_HDR)
 786                 tun->flags |= TUN_VNET_HDR;
 787         else
 788                 tun->flags &= ~TUN_VNET_HDR;
 789
 790         file->private_data = tun;
 791         tun->attached = 1;
 792         get_net(dev_net(tun->dev));
 793
 794         /* Make sure persistent devices do not get stuck in
 795          * xoff state.
 796          */
 797         if (netif_running(tun->dev))
 798                 netif_wake_queue(tun->dev);
 799
 800         strcpy(ifr->ifr_name, tun->dev->name);
 801         return 0;
 802
 803  err_free_dev:
 804         free_netdev(dev);
 805  failed:
 806         return err;
 807 }
 808
 809 static int tun_get_iff(struct net *net, struct file *file, struct ifreq *ifr)
 810 {
 811         struct tun_struct *tun = file->private_data;
 812
 813         if (!tun)
 814                 return -EBADFD;
 815
 816         DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
 817
 818         strcpy(ifr->ifr_name, tun->dev->name);
 819
 820         ifr->ifr_flags = 0;
 821
 822         if (ifr->ifr_flags & TUN_TUN_DEV)
 823                 ifr->ifr_flags |= IFF_TUN;
 824         else
 825                 ifr->ifr_flags |= IFF_TAP;
 826
 827         if (tun->flags & TUN_NO_PI)
 828                 ifr->ifr_flags |= IFF_NO_PI;
 829
 830         if (tun->flags & TUN_ONE_QUEUE)
 831                 ifr->ifr_flags |= IFF_ONE_QUEUE;
 832
 833         if (tun->flags & TUN_VNET_HDR)
 834                 ifr->ifr_flags |= IFF_VNET_HDR;
 835
 836         return 0;
 837 }
 838
 839 /* This is like a cut-down ethtool ops, except done via tun fd so no
 840  * privs required. */
 841 static int set_offload(struct net_device *dev, unsigned long arg)
 842 {
 843         unsigned int old_features, features;
 844
 845         old_features = dev->features;
 846         /* Unset features, set them as we chew on the arg. */
 847         features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
 848                                     |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6));
 849
 850         if (arg & TUN_F_CSUM) {
 851                 features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
 852                 arg &= ~TUN_F_CSUM;
 853
 854                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
 855                         if (arg & TUN_F_TSO_ECN) {
 856                                 features |= NETIF_F_TSO_ECN;
 857                                 arg &= ~TUN_F_TSO_ECN;
 858                         }
 859                         if (arg & TUN_F_TSO4)
 860                                 features |= NETIF_F_TSO;
 861                         if (arg & TUN_F_TSO6)
 862                                 features |= NETIF_F_TSO6;
 863                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
 864                 }
 865         }
 866
 867         /* This gives the user a way to test for new features in future by
 868          * trying to set them. */
 869         if (arg)
 870                 return -EINVAL;
 871
 872         dev->features = features;
 873         if (old_features != dev->features)
 874                 netdev_features_change(dev);
 875
 876         return 0;
 877 }
 878
 879 static int tun_chr_ioctl(struct inode *inode, struct file *file,
 880                          unsigned int cmd, unsigned long arg)
 881 {
 882         struct tun_struct *tun = file->private_data;
 883         void __user* argp = (void __user*)arg;
 884         struct ifreq ifr;
 885         int ret;
 886         DECLARE_MAC_BUF(mac);
 887
 888         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
 889                 if (copy_from_user(&ifr, argp, sizeof ifr))
 890                         return -EFAULT;
 891
 892         if (cmd == TUNSETIFF && !tun) {
 893                 int err;
 894
 895                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
 896
 897                 rtnl_lock();
 898                 err = tun_set_iff(current->nsproxy->net_ns, file, &ifr);
 899                 rtnl_unlock();
 900
 901                 if (err)
 902                         return err;
 903
 904                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
 905                         return -EFAULT;
 906                 return 0;
 907         }
 908
 909         if (cmd == TUNGETFEATURES) {
 910                 /* Currently this just means: "what IFF flags are valid?".
 911                  * This is needed because we never checked for invalid flags on
 912                  * TUNSETIFF. */
 913                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
 914                                 IFF_VNET_HDR,
 915                                 (unsigned int __user*)argp);
 916         }
 917
 918         if (!tun)
 919                 return -EBADFD;
 920
 921         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
 922
 923         switch (cmd) {
 924         case TUNGETIFF:
 925                 ret = tun_get_iff(current->nsproxy->net_ns, file, &ifr);
 926                 if (ret)
 927                         return ret;
 928
 929                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
 930                         return -EFAULT;
 931                 break;
 932
 933         case TUNSETNOCSUM:
 934                 /* Disable/Enable checksum */
 935                 if (arg)
 936                         tun->flags |= TUN_NOCHECKSUM;
 937                 else
 938                         tun->flags &= ~TUN_NOCHECKSUM;
 939
 940                 DBG(KERN_INFO "%s: checksum %s\n",
 941                     tun->dev->name, arg ? "disabled" : "enabled");
 942                 break;
 943
 944         case TUNSETPERSIST:
 945                 /* Disable/Enable persist mode */
 946                 if (arg)
 947                         tun->flags |= TUN_PERSIST;
 948                 else
 949                         tun->flags &= ~TUN_PERSIST;
 950
 951                 DBG(KERN_INFO "%s: persist %s\n",
 952                     tun->dev->name, arg ? "enabled" : "disabled");
 953                 break;
 954
 955         case TUNSETOWNER:
 956                 /* Set owner of the device */
 957                 tun->owner = (uid_t) arg;
 958
 959                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
 960                 break;
 961
 962         case TUNSETGROUP:
 963                 /* Set group of the device */
 964                 tun->group= (gid_t) arg;
 965
 966                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
 967                 break;
 968
 969         case TUNSETLINK:
 970                 /* Only allow setting the type when the interface is down */
 971                 rtnl_lock();
 972                 if (tun->dev->flags & IFF_UP) {
 973                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
 974                                 tun->dev->name);
 975                         ret = -EBUSY;
 976                 } else {
 977                         tun->dev->type = (int) arg;
 978                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
 979                         ret = 0;
 980                 }
 981                 rtnl_unlock();
 982                 return ret;
 983
 984 #ifdef TUN_DEBUG
 985         case TUNSETDEBUG:
 986                 tun->debug = arg;
 987                 break;
 988 #endif
 989         case TUNSETOFFLOAD:
 990                 rtnl_lock();
 991                 ret = set_offload(tun->dev, arg);
 992                 rtnl_unlock();
 993                 return ret;
 994
 995         case TUNSETTXFILTER:
 996                 /* Can be set only for TAPs */
 997                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
 998                         return -EINVAL;
 999                 rtnl_lock();
1000                 ret = update_filter(&tun->txflt, (void __user *)arg);
1001                 rtnl_unlock();
1002                 return ret;
1003
1004         case SIOCGIFHWADDR:
1005                 /* Get hw addres */
1006                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1007                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1008                 if (copy_to_user(argp, &ifr, sizeof ifr))
1009                         return -EFAULT;
1010                 return 0;
1011
1012         case SIOCSIFHWADDR:
1013                 /* Set hw address */
1014                 DBG(KERN_DEBUG "%s: set hw address: %s\n",
1015                         tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
1016
1017                 rtnl_lock();
1018                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1019                 rtnl_unlock();
1020                 return ret;
1021
1022         default:
1023                 return -EINVAL;
1024         };
1025
1026         return 0;
1027 }
1028
1029 static int tun_chr_fasync(int fd, struct file *file, int on)
1030 {
1031         struct tun_struct *tun = file->private_data;
1032         int ret;
1033
1034         if (!tun)
1035                 return -EBADFD;
1036
1037         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
1038
1039         lock_kernel();
1040         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1041                 goto out;
1042
1043         if (on) {
1044                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1045                 if (ret)
1046                         goto out;
1047                 tun->flags |= TUN_FASYNC;
1048         } else
1049                 tun->flags &= ~TUN_FASYNC;
1050         ret = 0;
1051 out:
1052         unlock_kernel();
1053         return ret;
1054 }
1055
1056 static int tun_chr_open(struct inode *inode, struct file * file)
1057 {
1058         cycle_kernel_lock();
1059         DBG1(KERN_INFO "tunX: tun_chr_open\n");
1060         file->private_data = NULL;
1061         return 0;
1062 }
1063
1064 static int tun_chr_close(struct inode *inode, struct file *file)
1065 {
1066         struct tun_struct *tun = file->private_data;
1067
1068         if (!tun)
1069                 return 0;
1070
1071         DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
1072
1073         rtnl_lock();
1074
1075         /* Detach from net device */
1076         file->private_data = NULL;
1077         tun->attached = 0;
1078         put_net(dev_net(tun->dev));
1079
1080         /* Drop read queue */
1081         skb_queue_purge(&tun->readq);
1082
1083         if (!(tun->flags & TUN_PERSIST)) {
1084                 list_del(&tun->list);
1085                 unregister_netdevice(tun->dev);
1086         }
1087
1088         rtnl_unlock();
1089
1090         return 0;
1091 }
1092
1093 static const struct file_operations tun_fops = {
1094         .owner  = THIS_MODULE,
1095         .llseek = no_llseek,
1096         .read  = do_sync_read,
1097         .aio_read  = tun_chr_aio_read,
1098         .write = do_sync_write,
1099         .aio_write = tun_chr_aio_write,
1100         .poll   = tun_chr_poll,
1101         .ioctl  = tun_chr_ioctl,
1102         .open   = tun_chr_open,
1103         .release = tun_chr_close,
1104         .fasync = tun_chr_fasync
1105 };
1106
1107 static struct miscdevice tun_miscdev = {
1108         .minor = TUN_MINOR,
1109         .name = "tun",
1110         .fops = &tun_fops,
1111 };
1112
1113 /* ethtool interface */
1114
1115 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1116 {
1117         cmd->supported          = 0;
1118         cmd->advertising        = 0;
1119         cmd->speed              = SPEED_10;
1120         cmd->duplex             = DUPLEX_FULL;
1121         cmd->port               = PORT_TP;
1122         cmd->phy_address        = 0;
1123         cmd->transceiver        = XCVR_INTERNAL;
1124         cmd->autoneg            = AUTONEG_DISABLE;
1125         cmd->maxtxpkt           = 0;
1126         cmd->maxrxpkt           = 0;
1127         return 0;
1128 }
1129
1130 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1131 {
1132         struct tun_struct *tun = netdev_priv(dev);
1133
1134         strcpy(info->driver, DRV_NAME);
1135         strcpy(info->version, DRV_VERSION);
1136         strcpy(info->fw_version, "N/A");
1137
1138         switch (tun->flags & TUN_TYPE_MASK) {
1139         case TUN_TUN_DEV:
1140                 strcpy(info->bus_info, "tun");
1141                 break;
1142         case TUN_TAP_DEV:
1143                 strcpy(info->bus_info, "tap");
1144                 break;
1145         }
1146 }
1147
1148 static u32 tun_get_msglevel(struct net_device *dev)
1149 {
1150 #ifdef TUN_DEBUG
1151         struct tun_struct *tun = netdev_priv(dev);
1152         return tun->debug;
1153 #else
1154         return -EOPNOTSUPP;
1155 #endif
1156 }
1157
1158 static void tun_set_msglevel(struct net_device *dev, u32 value)
1159 {
1160 #ifdef TUN_DEBUG
1161         struct tun_struct *tun = netdev_priv(dev);
1162         tun->debug = value;
1163 #endif
1164 }
1165
1166 static u32 tun_get_link(struct net_device *dev)
1167 {
1168         struct tun_struct *tun = netdev_priv(dev);
1169         return tun->attached;
1170 }
1171
1172 static u32 tun_get_rx_csum(struct net_device *dev)
1173 {
1174         struct tun_struct *tun = netdev_priv(dev);
1175         return (tun->flags & TUN_NOCHECKSUM) == 0;
1176 }
1177
1178 static int tun_set_rx_csum(struct net_device *dev, u32 data)
1179 {
1180         struct tun_struct *tun = netdev_priv(dev);
1181         if (data)
1182                 tun->flags &= ~TUN_NOCHECKSUM;
1183         else
1184                 tun->flags |= TUN_NOCHECKSUM;
1185         return 0;
1186 }
1187
1188 static const struct ethtool_ops tun_ethtool_ops = {
1189         .get_settings   = tun_get_settings,
1190         .get_drvinfo    = tun_get_drvinfo,
1191         .get_msglevel   = tun_get_msglevel,
1192         .set_msglevel   = tun_set_msglevel,
1193         .get_link       = tun_get_link,
1194         .get_rx_csum    = tun_get_rx_csum,
1195         .set_rx_csum    = tun_set_rx_csum
1196 };
1197
1198 static int tun_init_net(struct net *net)
1199 {
1200         struct tun_net *tn;
1201
1202         tn = kmalloc(sizeof(*tn), GFP_KERNEL);
1203         if (tn == NULL)
1204                 return -ENOMEM;
1205
1206         INIT_LIST_HEAD(&tn->dev_list);
1207
1208         if (net_assign_generic(net, tun_net_id, tn)) {
1209                 kfree(tn);
1210                 return -ENOMEM;
1211         }
1212
1213         return 0;
1214 }
1215
1216 static void tun_exit_net(struct net *net)
1217 {
1218         struct tun_net *tn;
1219         struct tun_struct *tun, *nxt;
1220
1221         tn = net_generic(net, tun_net_id);
1222
1223         rtnl_lock();
1224         list_for_each_entry_safe(tun, nxt, &tn->dev_list, list) {
1225                 DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
1226                 unregister_netdevice(tun->dev);
1227         }
1228         rtnl_unlock();
1229
1230         kfree(tn);
1231 }
1232
1233 static struct pernet_operations tun_net_ops = {
1234         .init = tun_init_net,
1235         .exit = tun_exit_net,
1236 };
1237
1238 static int __init tun_init(void)
1239 {
1240         int ret = 0;
1241
1242         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1243         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
1244
1245         ret = register_pernet_gen_device(&tun_net_id, &tun_net_ops);
1246         if (ret) {
1247                 printk(KERN_ERR "tun: Can't register pernet ops\n");
1248                 goto err_pernet;
1249         }
1250
1251         ret = misc_register(&tun_miscdev);
1252         if (ret) {
1253                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
1254                 goto err_misc;
1255         }
1256         return 0;
1257
1258 err_misc:
1259         unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
1260 err_pernet:
1261         return ret;
1262 }
1263
1264 static void tun_cleanup(void)
1265 {
1266         misc_deregister(&tun_miscdev);
1267         unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
1268 }
1269
1270 module_init(tun_init);
1271 module_exit(tun_cleanup);
1272 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1273 MODULE_AUTHOR(DRV_COPYRIGHT);
1274 MODULE_LICENSE("GPL");
1275 MODULE_ALIAS_MISCDEV(TUN_MINOR);