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 /* Remaining multicast addresses are hashed, 161 * unicast will leave the filter disabled. */ 162 memset(filter->mask, 0, sizeof(filter->mask)); 163 for (; n < uf.count; n++) { 164 if (!is_multicast_ether_addr(addr[n].u)) { 165 err = 0; /* no filter */ 166 goto done; 167 } 168 addr_hash_set(filter->mask, addr[n].u); 169 } 170 171 /* For ALLMULTI just set the mask to all ones. 172 * This overrides the mask populated above. */ 173 if ((uf.flags & TUN_FLT_ALLMULTI)) 174 memset(filter->mask, ~0, sizeof(filter->mask)); 175 176 /* Now enable the filter */ 177 wmb(); 178 filter->count = nexact; 179 180 /* Return the number of exact filters */ 181 err = nexact; 182 183 done: 184 kfree(addr); 185 return err; 186 } 187 188 /* Returns: 0 - drop, !=0 - accept */ 189 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 190 { 191 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 192 * at this point. */ 193 struct ethhdr *eh = (struct ethhdr *) skb->data; 194 int i; 195 196 /* Exact match */ 197 for (i = 0; i < filter->count; i++) 198 if (!compare_ether_addr(eh->h_dest, filter->addr[i])) 199 return 1; 200 201 /* Inexact match (multicast only) */ 202 if (is_multicast_ether_addr(eh->h_dest)) 203 return addr_hash_test(filter->mask, eh->h_dest); 204 205 return 0; 206 } 207 208 /* 209 * Checks whether the packet is accepted or not. 210 * Returns: 0 - drop, !=0 - accept 211 */ 212 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 213 { 214 if (!filter->count) 215 return 1; 216 217 return run_filter(filter, skb); 218 } 219 220 /* Network device part of the driver */ 221 222 static int tun_net_id; 223 struct tun_net { 224 struct list_head dev_list; 225 }; 226 227 static const struct ethtool_ops tun_ethtool_ops; 228 229 /* Net device open. */ 230 static int tun_net_open(struct net_device *dev) 231 { 232 netif_start_queue(dev); 233 return 0; 234 } 235 236 /* Net device close. */ 237 static int tun_net_close(struct net_device *dev) 238 { 239 netif_stop_queue(dev); 240 return 0; 241 } 242 243 /* Net device start xmit */ 244 static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 245 { 246 struct tun_struct *tun = netdev_priv(dev); 247 248 DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len); 249 250 /* Drop packet if interface is not attached */ 251 if (!tun->attached) 252 goto drop; 253 254 /* Drop if the filter does not like it. 255 * This is a noop if the filter is disabled. 256 * Filter can be enabled only for the TAP devices. */ 257 if (!check_filter(&tun->txflt, skb)) 258 goto drop; 259 260 if (skb_queue_len(&tun->readq) >= dev->tx_queue_len) { 261 if (!(tun->flags & TUN_ONE_QUEUE)) { 262 /* Normal queueing mode. */ 263 /* Packet scheduler handles dropping of further packets. */ 264 netif_stop_queue(dev); 265 266 /* We won't see all dropped packets individually, so overrun 267 * error is more appropriate. */ 268 dev->stats.tx_fifo_errors++; 269 } else { 270 /* Single queue mode. 271 * Driver handles dropping of all packets itself. */ 272 goto drop; 273 } 274 } 275 276 /* Enqueue packet */ 277 skb_queue_tail(&tun->readq, skb); 278 dev->trans_start = jiffies; 279 280 /* Notify and wake up reader process */ 281 if (tun->flags & TUN_FASYNC) 282 kill_fasync(&tun->fasync, SIGIO, POLL_IN); 283 wake_up_interruptible(&tun->read_wait); 284 return 0; 285 286 drop: 287 dev->stats.tx_dropped++; 288 kfree_skb(skb); 289 return 0; 290 } 291 292 static void tun_net_mclist(struct net_device *dev) 293 { 294 /* 295 * This callback is supposed to deal with mc filter in 296 * _rx_ path and has nothing to do with the _tx_ path. 297 * In rx path we always accept everything userspace gives us. 298 */ 299 return; 300 } 301 302 #define MIN_MTU 68 303 #define MAX_MTU 65535 304 305 static int 306 tun_net_change_mtu(struct net_device *dev, int new_mtu) 307 { 308 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 309 return -EINVAL; 310 dev->mtu = new_mtu; 311 return 0; 312 } 313 314 static const struct net_device_ops tun_netdev_ops = { 315 .ndo_open = tun_net_open, 316 .ndo_stop = tun_net_close, 317 .ndo_start_xmit = tun_net_xmit, 318 .ndo_change_mtu = tun_net_change_mtu, 319 }; 320 321 static const struct net_device_ops tap_netdev_ops = { 322 .ndo_open = tun_net_open, 323 .ndo_stop = tun_net_close, 324 .ndo_start_xmit = tun_net_xmit, 325 .ndo_change_mtu = tun_net_change_mtu, 326 .ndo_set_multicast_list = tun_net_mclist, 327 .ndo_set_mac_address = eth_mac_addr, 328 .ndo_validate_addr = eth_validate_addr, 329 }; 330 331 /* Initialize net device. */ 332 static void tun_net_init(struct net_device *dev) 333 { 334 struct tun_struct *tun = netdev_priv(dev); 335 336 switch (tun->flags & TUN_TYPE_MASK) { 337 case TUN_TUN_DEV: 338 dev->netdev_ops = &tun_netdev_ops; 339 340 /* Point-to-Point TUN Device */ 341 dev->hard_header_len = 0; 342 dev->addr_len = 0; 343 dev->mtu = 1500; 344 345 /* Zero header length */ 346 dev->type = ARPHRD_NONE; 347 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 348 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 349 break; 350 351 case TUN_TAP_DEV: 352 dev->netdev_ops = &tap_netdev_ops; 353 /* Ethernet TAP Device */ 354 ether_setup(dev); 355 356 random_ether_addr(dev->dev_addr); 357 358 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 359 break; 360 } 361 } 362 363 /* Character device part */ 364 365 /* Poll */ 366 static unsigned int tun_chr_poll(struct file *file, poll_table * wait) 367 { 368 struct tun_struct *tun = file->private_data; 369 unsigned int mask = POLLOUT | POLLWRNORM; 370 371 if (!tun) 372 return -EBADFD; 373 374 DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name); 375 376 poll_wait(file, &tun->read_wait, wait); 377 378 if (!skb_queue_empty(&tun->readq)) 379 mask |= POLLIN | POLLRDNORM; 380 381 return mask; 382 } 383 384 /* prepad is the amount to reserve at front. len is length after that. 385 * linear is a hint as to how much to copy (usually headers). */ 386 static struct sk_buff *tun_alloc_skb(size_t prepad, size_t len, size_t linear, 387 gfp_t gfp) 388 { 389 struct sk_buff *skb; 390 unsigned int i; 391 392 skb = alloc_skb(prepad + len, gfp|__GFP_NOWARN); 393 if (skb) { 394 skb_reserve(skb, prepad); 395 skb_put(skb, len); 396 return skb; 397 } 398 399 /* Under a page? Don't bother with paged skb. */ 400 if (prepad + len < PAGE_SIZE) 401 return NULL; 402 403 /* Start with a normal skb, and add pages. */ 404 skb = alloc_skb(prepad + linear, gfp); 405 if (!skb) 406 return NULL; 407 408 skb_reserve(skb, prepad); 409 skb_put(skb, linear); 410 411 len -= linear; 412 413 for (i = 0; i < MAX_SKB_FRAGS; i++) { 414 skb_frag_t *f = &skb_shinfo(skb)->frags[i]; 415 416 f->page = alloc_page(gfp|__GFP_ZERO); 417 if (!f->page) 418 break; 419 420 f->page_offset = 0; 421 f->size = PAGE_SIZE; 422 423 skb->data_len += PAGE_SIZE; 424 skb->len += PAGE_SIZE; 425 skb->truesize += PAGE_SIZE; 426 skb_shinfo(skb)->nr_frags++; 427 428 if (len < PAGE_SIZE) { 429 len = 0; 430 break; 431 } 432 len -= PAGE_SIZE; 433 } 434 435 /* Too large, or alloc fail? */ 436 if (unlikely(len)) { 437 kfree_skb(skb); 438 skb = NULL; 439 } 440 441 return skb; 442 } 443 444 /* Get packet from user space buffer */ 445 static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count) 446 { 447 struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) }; 448 struct sk_buff *skb; 449 size_t len = count, align = 0; 450 struct virtio_net_hdr gso = { 0 }; 451 452 if (!(tun->flags & TUN_NO_PI)) { 453 if ((len -= sizeof(pi)) > count) 454 return -EINVAL; 455 456 if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi))) 457 return -EFAULT; 458 } 459 460 if (tun->flags & TUN_VNET_HDR) { 461 if ((len -= sizeof(gso)) > count) 462 return -EINVAL; 463 464 if (memcpy_fromiovec((void *)&gso, iv, sizeof(gso))) 465 return -EFAULT; 466 467 if (gso.hdr_len > len) 468 return -EINVAL; 469 } 470 471 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { 472 align = NET_IP_ALIGN; 473 if (unlikely(len < ETH_HLEN)) 474 return -EINVAL; 475 } 476 477 if (!(skb = tun_alloc_skb(align, len, gso.hdr_len, GFP_KERNEL))) { 478 tun->dev->stats.rx_dropped++; 479 return -ENOMEM; 480 } 481 482 if (skb_copy_datagram_from_iovec(skb, 0, iv, len)) { 483 tun->dev->stats.rx_dropped++; 484 kfree_skb(skb); 485 return -EFAULT; 486 } 487 488 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 489 if (!skb_partial_csum_set(skb, gso.csum_start, 490 gso.csum_offset)) { 491 tun->dev->stats.rx_frame_errors++; 492 kfree_skb(skb); 493 return -EINVAL; 494 } 495 } else if (tun->flags & TUN_NOCHECKSUM) 496 skb->ip_summed = CHECKSUM_UNNECESSARY; 497 498 switch (tun->flags & TUN_TYPE_MASK) { 499 case TUN_TUN_DEV: 500 if (tun->flags & TUN_NO_PI) { 501 switch (skb->data[0] & 0xf0) { 502 case 0x40: 503 pi.proto = htons(ETH_P_IP); 504 break; 505 case 0x60: 506 pi.proto = htons(ETH_P_IPV6); 507 break; 508 default: 509 tun->dev->stats.rx_dropped++; 510 kfree_skb(skb); 511 return -EINVAL; 512 } 513 } 514 515 skb_reset_mac_header(skb); 516 skb->protocol = pi.proto; 517 skb->dev = tun->dev; 518 break; 519 case TUN_TAP_DEV: 520 skb->protocol = eth_type_trans(skb, tun->dev); 521 break; 522 }; 523 524 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 525 pr_debug("GSO!\n"); 526 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 527 case VIRTIO_NET_HDR_GSO_TCPV4: 528 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 529 break; 530 case VIRTIO_NET_HDR_GSO_TCPV6: 531 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 532 break; 533 default: 534 tun->dev->stats.rx_frame_errors++; 535 kfree_skb(skb); 536 return -EINVAL; 537 } 538 539 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 540 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 541 542 skb_shinfo(skb)->gso_size = gso.gso_size; 543 if (skb_shinfo(skb)->gso_size == 0) { 544 tun->dev->stats.rx_frame_errors++; 545 kfree_skb(skb); 546 return -EINVAL; 547 } 548 549 /* Header must be checked, and gso_segs computed. */ 550 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 551 skb_shinfo(skb)->gso_segs = 0; 552 } 553 554 netif_rx_ni(skb); 555 556 tun->dev->stats.rx_packets++; 557 tun->dev->stats.rx_bytes += len; 558 559 return count; 560 } 561 562 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 563 unsigned long count, loff_t pos) 564 { 565 struct tun_struct *tun = iocb->ki_filp->private_data; 566 567 if (!tun) 568 return -EBADFD; 569 570 DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count); 571 572 return tun_get_user(tun, (struct iovec *) iv, iov_length(iv, count)); 573 } 574 575 /* Put packet to the user space buffer */ 576 static __inline__ ssize_t tun_put_user(struct tun_struct *tun, 577 struct sk_buff *skb, 578 struct iovec *iv, int len) 579 { 580 struct tun_pi pi = { 0, skb->protocol }; 581 ssize_t total = 0; 582 583 if (!(tun->flags & TUN_NO_PI)) { 584 if ((len -= sizeof(pi)) < 0) 585 return -EINVAL; 586 587 if (len < skb->len) { 588 /* Packet will be striped */ 589 pi.flags |= TUN_PKT_STRIP; 590 } 591 592 if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi))) 593 return -EFAULT; 594 total += sizeof(pi); 595 } 596 597 if (tun->flags & TUN_VNET_HDR) { 598 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 599 if ((len -= sizeof(gso)) < 0) 600 return -EINVAL; 601 602 if (skb_is_gso(skb)) { 603 struct skb_shared_info *sinfo = skb_shinfo(skb); 604 605 /* This is a hint as to how much should be linear. */ 606 gso.hdr_len = skb_headlen(skb); 607 gso.gso_size = sinfo->gso_size; 608 if (sinfo->gso_type & SKB_GSO_TCPV4) 609 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 610 else if (sinfo->gso_type & SKB_GSO_TCPV6) 611 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 612 else 613 BUG(); 614 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 615 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 616 } else 617 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 618 619 if (skb->ip_summed == CHECKSUM_PARTIAL) { 620 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 621 gso.csum_start = skb->csum_start - skb_headroom(skb); 622 gso.csum_offset = skb->csum_offset; 623 } /* else everything is zero */ 624 625 if (unlikely(memcpy_toiovec(iv, (void *)&gso, sizeof(gso)))) 626 return -EFAULT; 627 total += sizeof(gso); 628 } 629 630 len = min_t(int, skb->len, len); 631 632 skb_copy_datagram_iovec(skb, 0, iv, len); 633 total += len; 634 635 tun->dev->stats.tx_packets++; 636 tun->dev->stats.tx_bytes += len; 637 638 return total; 639 } 640 641 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 642 unsigned long count, loff_t pos) 643 { 644 struct file *file = iocb->ki_filp; 645 struct tun_struct *tun = file->private_data; 646 DECLARE_WAITQUEUE(wait, current); 647 struct sk_buff *skb; 648 ssize_t len, ret = 0; 649 650 if (!tun) 651 return -EBADFD; 652 653 DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name); 654 655 len = iov_length(iv, count); 656 if (len < 0) 657 return -EINVAL; 658 659 add_wait_queue(&tun->read_wait, &wait); 660 while (len) { 661 current->state = TASK_INTERRUPTIBLE; 662 663 /* Read frames from the queue */ 664 if (!(skb=skb_dequeue(&tun->readq))) { 665 if (file->f_flags & O_NONBLOCK) { 666 ret = -EAGAIN; 667 break; 668 } 669 if (signal_pending(current)) { 670 ret = -ERESTARTSYS; 671 break; 672 } 673 674 /* Nothing to read, let's sleep */ 675 schedule(); 676 continue; 677 } 678 netif_wake_queue(tun->dev); 679 680 ret = tun_put_user(tun, skb, (struct iovec *) iv, len); 681 kfree_skb(skb); 682 break; 683 } 684 685 current->state = TASK_RUNNING; 686 remove_wait_queue(&tun->read_wait, &wait); 687 688 return ret; 689 } 690 691 static void tun_setup(struct net_device *dev) 692 { 693 struct tun_struct *tun = netdev_priv(dev); 694 695 skb_queue_head_init(&tun->readq); 696 init_waitqueue_head(&tun->read_wait); 697 698 tun->owner = -1; 699 tun->group = -1; 700 701 dev->ethtool_ops = &tun_ethtool_ops; 702 dev->destructor = free_netdev; 703 dev->features |= NETIF_F_NETNS_LOCAL; 704 } 705 706 static struct tun_struct *tun_get_by_name(struct tun_net *tn, const char *name) 707 { 708 struct tun_struct *tun; 709 710 ASSERT_RTNL(); 711 list_for_each_entry(tun, &tn->dev_list, list) { 712 if (!strncmp(tun->dev->name, name, IFNAMSIZ)) 713 return tun; 714 } 715 716 return NULL; 717 } 718 719 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 720 { 721 struct tun_net *tn; 722 struct tun_struct *tun; 723 struct net_device *dev; 724 const struct cred *cred = current_cred(); 725 int err; 726 727 tn = net_generic(net, tun_net_id); 728 tun = tun_get_by_name(tn, ifr->ifr_name); 729 if (tun) { 730 if (tun->attached) 731 return -EBUSY; 732 733 /* Check permissions */ 734 if (((tun->owner != -1 && 735 cred->euid != tun->owner) || 736 (tun->group != -1 && 737 cred->egid != tun->group)) && 738 !capable(CAP_NET_ADMIN)) { 739 return -EPERM; 740 } 741 } 742 else if (__dev_get_by_name(net, ifr->ifr_name)) 743 return -EINVAL; 744 else { 745 char *name; 746 unsigned long flags = 0; 747 748 err = -EINVAL; 749 750 if (!capable(CAP_NET_ADMIN)) 751 return -EPERM; 752 753 /* Set dev type */ 754 if (ifr->ifr_flags & IFF_TUN) { 755 /* TUN device */ 756 flags |= TUN_TUN_DEV; 757 name = "tun%d"; 758 } else if (ifr->ifr_flags & IFF_TAP) { 759 /* TAP device */ 760 flags |= TUN_TAP_DEV; 761 name = "tap%d"; 762 } else 763 goto failed; 764 765 if (*ifr->ifr_name) 766 name = ifr->ifr_name; 767 768 dev = alloc_netdev(sizeof(struct tun_struct), name, 769 tun_setup); 770 if (!dev) 771 return -ENOMEM; 772 773 dev_net_set(dev, net); 774 775 tun = netdev_priv(dev); 776 tun->dev = dev; 777 tun->flags = flags; 778 tun->txflt.count = 0; 779 780 tun_net_init(dev); 781 782 if (strchr(dev->name, '%')) { 783 err = dev_alloc_name(dev, dev->name); 784 if (err < 0) 785 goto err_free_dev; 786 } 787 788 err = register_netdevice(tun->dev); 789 if (err < 0) 790 goto err_free_dev; 791 792 list_add(&tun->list, &tn->dev_list); 793 } 794 795 DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name); 796 797 if (ifr->ifr_flags & IFF_NO_PI) 798 tun->flags |= TUN_NO_PI; 799 else 800 tun->flags &= ~TUN_NO_PI; 801 802 if (ifr->ifr_flags & IFF_ONE_QUEUE) 803 tun->flags |= TUN_ONE_QUEUE; 804 else 805 tun->flags &= ~TUN_ONE_QUEUE; 806 807 if (ifr->ifr_flags & IFF_VNET_HDR) 808 tun->flags |= TUN_VNET_HDR; 809 else 810 tun->flags &= ~TUN_VNET_HDR; 811 812 file->private_data = tun; 813 tun->attached = 1; 814 get_net(dev_net(tun->dev)); 815 816 /* Make sure persistent devices do not get stuck in 817 * xoff state. 818 */ 819 if (netif_running(tun->dev)) 820 netif_wake_queue(tun->dev); 821 822 strcpy(ifr->ifr_name, tun->dev->name); 823 return 0; 824 825 err_free_dev: 826 free_netdev(dev); 827 failed: 828 return err; 829 } 830 831 static int tun_get_iff(struct net *net, struct file *file, struct ifreq *ifr) 832 { 833 struct tun_struct *tun = file->private_data; 834 835 if (!tun) 836 return -EBADFD; 837 838 DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name); 839 840 strcpy(ifr->ifr_name, tun->dev->name); 841 842 ifr->ifr_flags = 0; 843 844 if (ifr->ifr_flags & TUN_TUN_DEV) 845 ifr->ifr_flags |= IFF_TUN; 846 else 847 ifr->ifr_flags |= IFF_TAP; 848 849 if (tun->flags & TUN_NO_PI) 850 ifr->ifr_flags |= IFF_NO_PI; 851 852 if (tun->flags & TUN_ONE_QUEUE) 853 ifr->ifr_flags |= IFF_ONE_QUEUE; 854 855 if (tun->flags & TUN_VNET_HDR) 856 ifr->ifr_flags |= IFF_VNET_HDR; 857 858 return 0; 859 } 860 861 /* This is like a cut-down ethtool ops, except done via tun fd so no 862 * privs required. */ 863 static int set_offload(struct net_device *dev, unsigned long arg) 864 { 865 unsigned int old_features, features; 866 867 old_features = dev->features; 868 /* Unset features, set them as we chew on the arg. */ 869 features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST 870 |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6)); 871 872 if (arg & TUN_F_CSUM) { 873 features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST; 874 arg &= ~TUN_F_CSUM; 875 876 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 877 if (arg & TUN_F_TSO_ECN) { 878 features |= NETIF_F_TSO_ECN; 879 arg &= ~TUN_F_TSO_ECN; 880 } 881 if (arg & TUN_F_TSO4) 882 features |= NETIF_F_TSO; 883 if (arg & TUN_F_TSO6) 884 features |= NETIF_F_TSO6; 885 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 886 } 887 } 888 889 /* This gives the user a way to test for new features in future by 890 * trying to set them. */ 891 if (arg) 892 return -EINVAL; 893 894 dev->features = features; 895 if (old_features != dev->features) 896 netdev_features_change(dev); 897 898 return 0; 899 } 900 901 static int tun_chr_ioctl(struct inode *inode, struct file *file, 902 unsigned int cmd, unsigned long arg) 903 { 904 struct tun_struct *tun = file->private_data; 905 void __user* argp = (void __user*)arg; 906 struct ifreq ifr; 907 int ret; 908 909 if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) 910 if (copy_from_user(&ifr, argp, sizeof ifr)) 911 return -EFAULT; 912 913 if (cmd == TUNSETIFF && !tun) { 914 int err; 915 916 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 917 918 rtnl_lock(); 919 err = tun_set_iff(current->nsproxy->net_ns, file, &ifr); 920 rtnl_unlock(); 921 922 if (err) 923 return err; 924 925 if (copy_to_user(argp, &ifr, sizeof(ifr))) 926 return -EFAULT; 927 return 0; 928 } 929 930 if (cmd == TUNGETFEATURES) { 931 /* Currently this just means: "what IFF flags are valid?". 932 * This is needed because we never checked for invalid flags on 933 * TUNSETIFF. */ 934 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | 935 IFF_VNET_HDR, 936 (unsigned int __user*)argp); 937 } 938 939 if (!tun) 940 return -EBADFD; 941 942 DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd); 943 944 switch (cmd) { 945 case TUNGETIFF: 946 ret = tun_get_iff(current->nsproxy->net_ns, file, &ifr); 947 if (ret) 948 return ret; 949 950 if (copy_to_user(argp, &ifr, sizeof(ifr))) 951 return -EFAULT; 952 break; 953 954 case TUNSETNOCSUM: 955 /* Disable/Enable checksum */ 956 if (arg) 957 tun->flags |= TUN_NOCHECKSUM; 958 else 959 tun->flags &= ~TUN_NOCHECKSUM; 960 961 DBG(KERN_INFO "%s: checksum %s\n", 962 tun->dev->name, arg ? "disabled" : "enabled"); 963 break; 964 965 case TUNSETPERSIST: 966 /* Disable/Enable persist mode */ 967 if (arg) 968 tun->flags |= TUN_PERSIST; 969 else 970 tun->flags &= ~TUN_PERSIST; 971 972 DBG(KERN_INFO "%s: persist %s\n", 973 tun->dev->name, arg ? "enabled" : "disabled"); 974 break; 975 976 case TUNSETOWNER: 977 /* Set owner of the device */ 978 tun->owner = (uid_t) arg; 979 980 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner); 981 break; 982 983 case TUNSETGROUP: 984 /* Set group of the device */ 985 tun->group= (gid_t) arg; 986 987 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group); 988 break; 989 990 case TUNSETLINK: 991 /* Only allow setting the type when the interface is down */ 992 rtnl_lock(); 993 if (tun->dev->flags & IFF_UP) { 994 DBG(KERN_INFO "%s: Linktype set failed because interface is up\n", 995 tun->dev->name); 996 ret = -EBUSY; 997 } else { 998 tun->dev->type = (int) arg; 999 DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type); 1000 ret = 0; 1001 } 1002 rtnl_unlock(); 1003 return ret; 1004 1005 #ifdef TUN_DEBUG 1006 case TUNSETDEBUG: 1007 tun->debug = arg; 1008 break; 1009 #endif 1010 case TUNSETOFFLOAD: 1011 rtnl_lock(); 1012 ret = set_offload(tun->dev, arg); 1013 rtnl_unlock(); 1014 return ret; 1015 1016 case TUNSETTXFILTER: 1017 /* Can be set only for TAPs */ 1018 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 1019 return -EINVAL; 1020 rtnl_lock(); 1021 ret = update_filter(&tun->txflt, (void __user *)arg); 1022 rtnl_unlock(); 1023 return ret; 1024 1025 case SIOCGIFHWADDR: 1026 /* Get hw addres */ 1027 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 1028 ifr.ifr_hwaddr.sa_family = tun->dev->type; 1029 if (copy_to_user(argp, &ifr, sizeof ifr)) 1030 return -EFAULT; 1031 return 0; 1032 1033 case SIOCSIFHWADDR: 1034 /* Set hw address */ 1035 DBG(KERN_DEBUG "%s: set hw address: %pM\n", 1036 tun->dev->name, ifr.ifr_hwaddr.sa_data); 1037 1038 rtnl_lock(); 1039 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 1040 rtnl_unlock(); 1041 return ret; 1042 1043 default: 1044 return -EINVAL; 1045 }; 1046 1047 return 0; 1048 } 1049 1050 static int tun_chr_fasync(int fd, struct file *file, int on) 1051 { 1052 struct tun_struct *tun = file->private_data; 1053 int ret; 1054 1055 if (!tun) 1056 return -EBADFD; 1057 1058 DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on); 1059 1060 lock_kernel(); 1061 if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0) 1062 goto out; 1063 1064 if (on) { 1065 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 1066 if (ret) 1067 goto out; 1068 tun->flags |= TUN_FASYNC; 1069 } else 1070 tun->flags &= ~TUN_FASYNC; 1071 ret = 0; 1072 out: 1073 unlock_kernel(); 1074 return ret; 1075 } 1076 1077 static int tun_chr_open(struct inode *inode, struct file * file) 1078 { 1079 cycle_kernel_lock(); 1080 DBG1(KERN_INFO "tunX: tun_chr_open\n"); 1081 file->private_data = NULL; 1082 return 0; 1083 } 1084 1085 static int tun_chr_close(struct inode *inode, struct file *file) 1086 { 1087 struct tun_struct *tun = file->private_data; 1088 1089 if (!tun) 1090 return 0; 1091 1092 DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name); 1093 1094 rtnl_lock(); 1095 1096 /* Detach from net device */ 1097 file->private_data = NULL; 1098 tun->attached = 0; 1099 put_net(dev_net(tun->dev)); 1100 1101 /* Drop read queue */ 1102 skb_queue_purge(&tun->readq); 1103 1104 if (!(tun->flags & TUN_PERSIST)) { 1105 list_del(&tun->list); 1106 unregister_netdevice(tun->dev); 1107 } 1108 1109 rtnl_unlock(); 1110 1111 return 0; 1112 } 1113 1114 static const struct file_operations tun_fops = { 1115 .owner = THIS_MODULE, 1116 .llseek = no_llseek, 1117 .read = do_sync_read, 1118 .aio_read = tun_chr_aio_read, 1119 .write = do_sync_write, 1120 .aio_write = tun_chr_aio_write, 1121 .poll = tun_chr_poll, 1122 .ioctl = tun_chr_ioctl, 1123 .open = tun_chr_open, 1124 .release = tun_chr_close, 1125 .fasync = tun_chr_fasync 1126 }; 1127 1128 static struct miscdevice tun_miscdev = { 1129 .minor = TUN_MINOR, 1130 .name = "tun", 1131 .fops = &tun_fops, 1132 }; 1133 1134 /* ethtool interface */ 1135 1136 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 1137 { 1138 cmd->supported = 0; 1139 cmd->advertising = 0; 1140 cmd->speed = SPEED_10; 1141 cmd->duplex = DUPLEX_FULL; 1142 cmd->port = PORT_TP; 1143 cmd->phy_address = 0; 1144 cmd->transceiver = XCVR_INTERNAL; 1145 cmd->autoneg = AUTONEG_DISABLE; 1146 cmd->maxtxpkt = 0; 1147 cmd->maxrxpkt = 0; 1148 return 0; 1149 } 1150 1151 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 1152 { 1153 struct tun_struct *tun = netdev_priv(dev); 1154 1155 strcpy(info->driver, DRV_NAME); 1156 strcpy(info->version, DRV_VERSION); 1157 strcpy(info->fw_version, "N/A"); 1158 1159 switch (tun->flags & TUN_TYPE_MASK) { 1160 case TUN_TUN_DEV: 1161 strcpy(info->bus_info, "tun"); 1162 break; 1163 case TUN_TAP_DEV: 1164 strcpy(info->bus_info, "tap"); 1165 break; 1166 } 1167 } 1168 1169 static u32 tun_get_msglevel(struct net_device *dev) 1170 { 1171 #ifdef TUN_DEBUG 1172 struct tun_struct *tun = netdev_priv(dev); 1173 return tun->debug; 1174 #else 1175 return -EOPNOTSUPP; 1176 #endif 1177 } 1178 1179 static void tun_set_msglevel(struct net_device *dev, u32 value) 1180 { 1181 #ifdef TUN_DEBUG 1182 struct tun_struct *tun = netdev_priv(dev); 1183 tun->debug = value; 1184 #endif 1185 } 1186 1187 static u32 tun_get_link(struct net_device *dev) 1188 { 1189 struct tun_struct *tun = netdev_priv(dev); 1190 return tun->attached; 1191 } 1192 1193 static u32 tun_get_rx_csum(struct net_device *dev) 1194 { 1195 struct tun_struct *tun = netdev_priv(dev); 1196 return (tun->flags & TUN_NOCHECKSUM) == 0; 1197 } 1198 1199 static int tun_set_rx_csum(struct net_device *dev, u32 data) 1200 { 1201 struct tun_struct *tun = netdev_priv(dev); 1202 if (data) 1203 tun->flags &= ~TUN_NOCHECKSUM; 1204 else 1205 tun->flags |= TUN_NOCHECKSUM; 1206 return 0; 1207 } 1208 1209 static const struct ethtool_ops tun_ethtool_ops = { 1210 .get_settings = tun_get_settings, 1211 .get_drvinfo = tun_get_drvinfo, 1212 .get_msglevel = tun_get_msglevel, 1213 .set_msglevel = tun_set_msglevel, 1214 .get_link = tun_get_link, 1215 .get_rx_csum = tun_get_rx_csum, 1216 .set_rx_csum = tun_set_rx_csum 1217 }; 1218 1219 static int tun_init_net(struct net *net) 1220 { 1221 struct tun_net *tn; 1222 1223 tn = kmalloc(sizeof(*tn), GFP_KERNEL); 1224 if (tn == NULL) 1225 return -ENOMEM; 1226 1227 INIT_LIST_HEAD(&tn->dev_list); 1228 1229 if (net_assign_generic(net, tun_net_id, tn)) { 1230 kfree(tn); 1231 return -ENOMEM; 1232 } 1233 1234 return 0; 1235 } 1236 1237 static void tun_exit_net(struct net *net) 1238 { 1239 struct tun_net *tn; 1240 struct tun_struct *tun, *nxt; 1241 1242 tn = net_generic(net, tun_net_id); 1243 1244 rtnl_lock(); 1245 list_for_each_entry_safe(tun, nxt, &tn->dev_list, list) { 1246 DBG(KERN_INFO "%s cleaned up\n", tun->dev->name); 1247 unregister_netdevice(tun->dev); 1248 } 1249 rtnl_unlock(); 1250 1251 kfree(tn); 1252 } 1253 1254 static struct pernet_operations tun_net_ops = { 1255 .init = tun_init_net, 1256 .exit = tun_exit_net, 1257 }; 1258 1259 static int __init tun_init(void) 1260 { 1261 int ret = 0; 1262 1263 printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 1264 printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT); 1265 1266 ret = register_pernet_gen_device(&tun_net_id, &tun_net_ops); 1267 if (ret) { 1268 printk(KERN_ERR "tun: Can't register pernet ops\n"); 1269 goto err_pernet; 1270 } 1271 1272 ret = misc_register(&tun_miscdev); 1273 if (ret) { 1274 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR); 1275 goto err_misc; 1276 } 1277 return 0; 1278 1279 err_misc: 1280 unregister_pernet_gen_device(tun_net_id, &tun_net_ops); 1281 err_pernet: 1282 return ret; 1283 } 1284 1285 static void tun_cleanup(void) 1286 { 1287 misc_deregister(&tun_miscdev); 1288 unregister_pernet_gen_device(tun_net_id, &tun_net_ops); 1289 } 1290 1291 module_init(tun_init); 1292 module_exit(tun_cleanup); 1293 MODULE_DESCRIPTION(DRV_DESCRIPTION); 1294 MODULE_AUTHOR(DRV_COPYRIGHT); 1295 MODULE_LICENSE("GPL"); 1296 MODULE_ALIAS_MISCDEV(TUN_MINOR); 1297