1 /* 2 * TUN - Universal TUN/TAP device driver. 3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $ 16 */ 17 18 /* 19 * Changes: 20 * 21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14 22 * Add TUNSETLINK ioctl to set the link encapsulation 23 * 24 * Mark Smith <markzzzsmith@yahoo.com.au> 25 * Use eth_random_addr() for tap MAC address. 26 * 27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20 28 * Fixes in packet dropping, queue length setting and queue wakeup. 29 * Increased default tx queue length. 30 * Added ethtool API. 31 * Minor cleanups 32 * 33 * Daniel Podlejski <underley@underley.eu.org> 34 * Modifications for 2.3.99-pre5 kernel. 35 */ 36 37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 38 39 #define DRV_NAME "tun" 40 #define DRV_VERSION "1.6" 41 #define DRV_DESCRIPTION "Universal TUN/TAP device driver" 42 #define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>" 43 44 #include <linux/module.h> 45 #include <linux/errno.h> 46 #include <linux/kernel.h> 47 #include <linux/major.h> 48 #include <linux/slab.h> 49 #include <linux/poll.h> 50 #include <linux/fcntl.h> 51 #include <linux/init.h> 52 #include <linux/skbuff.h> 53 #include <linux/netdevice.h> 54 #include <linux/etherdevice.h> 55 #include <linux/miscdevice.h> 56 #include <linux/ethtool.h> 57 #include <linux/rtnetlink.h> 58 #include <linux/compat.h> 59 #include <linux/if.h> 60 #include <linux/if_arp.h> 61 #include <linux/if_ether.h> 62 #include <linux/if_tun.h> 63 #include <linux/crc32.h> 64 #include <linux/nsproxy.h> 65 #include <linux/virtio_net.h> 66 #include <linux/rcupdate.h> 67 #include <net/net_namespace.h> 68 #include <net/netns/generic.h> 69 #include <net/rtnetlink.h> 70 #include <net/sock.h> 71 #include <net/cls_cgroup.h> 72 73 #include <asm/uaccess.h> 74 75 /* Uncomment to enable debugging */ 76 /* #define TUN_DEBUG 1 */ 77 78 #ifdef TUN_DEBUG 79 static int debug; 80 81 #define tun_debug(level, tun, fmt, args...) \ 82 do { \ 83 if (tun->debug) \ 84 netdev_printk(level, tun->dev, fmt, ##args); \ 85 } while (0) 86 #define DBG1(level, fmt, args...) \ 87 do { \ 88 if (debug == 2) \ 89 printk(level fmt, ##args); \ 90 } while (0) 91 #else 92 #define tun_debug(level, tun, fmt, args...) \ 93 do { \ 94 if (0) \ 95 netdev_printk(level, tun->dev, fmt, ##args); \ 96 } while (0) 97 #define DBG1(level, fmt, args...) \ 98 do { \ 99 if (0) \ 100 printk(level fmt, ##args); \ 101 } while (0) 102 #endif 103 104 #define GOODCOPY_LEN 128 105 106 #define FLT_EXACT_COUNT 8 107 struct tap_filter { 108 unsigned int count; /* Number of addrs. Zero means disabled */ 109 u32 mask[2]; /* Mask of the hashed addrs */ 110 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; 111 }; 112 113 struct tun_file { 114 atomic_t count; 115 struct tun_struct *tun; 116 struct net *net; 117 }; 118 119 struct tun_sock; 120 121 struct tun_struct { 122 struct tun_file *tfile; 123 unsigned int flags; 124 kuid_t owner; 125 kgid_t group; 126 127 struct net_device *dev; 128 netdev_features_t set_features; 129 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ 130 NETIF_F_TSO6|NETIF_F_UFO) 131 struct fasync_struct *fasync; 132 133 struct tap_filter txflt; 134 struct socket socket; 135 struct socket_wq wq; 136 137 int vnet_hdr_sz; 138 139 #ifdef TUN_DEBUG 140 int debug; 141 #endif 142 }; 143 144 struct tun_sock { 145 struct sock sk; 146 struct tun_struct *tun; 147 }; 148 149 static inline struct tun_sock *tun_sk(struct sock *sk) 150 { 151 return container_of(sk, struct tun_sock, sk); 152 } 153 154 static int tun_attach(struct tun_struct *tun, struct file *file) 155 { 156 struct tun_file *tfile = file->private_data; 157 int err; 158 159 ASSERT_RTNL(); 160 161 netif_tx_lock_bh(tun->dev); 162 163 err = -EINVAL; 164 if (tfile->tun) 165 goto out; 166 167 err = -EBUSY; 168 if (tun->tfile) 169 goto out; 170 171 err = 0; 172 tfile->tun = tun; 173 tun->tfile = tfile; 174 tun->socket.file = file; 175 netif_carrier_on(tun->dev); 176 dev_hold(tun->dev); 177 sock_hold(tun->socket.sk); 178 atomic_inc(&tfile->count); 179 180 out: 181 netif_tx_unlock_bh(tun->dev); 182 return err; 183 } 184 185 static void __tun_detach(struct tun_struct *tun) 186 { 187 /* Detach from net device */ 188 netif_tx_lock_bh(tun->dev); 189 netif_carrier_off(tun->dev); 190 tun->tfile = NULL; 191 netif_tx_unlock_bh(tun->dev); 192 193 /* Drop read queue */ 194 skb_queue_purge(&tun->socket.sk->sk_receive_queue); 195 196 /* Drop the extra count on the net device */ 197 dev_put(tun->dev); 198 } 199 200 static void tun_detach(struct tun_struct *tun) 201 { 202 rtnl_lock(); 203 __tun_detach(tun); 204 rtnl_unlock(); 205 } 206 207 static struct tun_struct *__tun_get(struct tun_file *tfile) 208 { 209 struct tun_struct *tun = NULL; 210 211 if (atomic_inc_not_zero(&tfile->count)) 212 tun = tfile->tun; 213 214 return tun; 215 } 216 217 static struct tun_struct *tun_get(struct file *file) 218 { 219 return __tun_get(file->private_data); 220 } 221 222 static void tun_put(struct tun_struct *tun) 223 { 224 struct tun_file *tfile = tun->tfile; 225 226 if (atomic_dec_and_test(&tfile->count)) 227 tun_detach(tfile->tun); 228 } 229 230 /* TAP filtering */ 231 static void addr_hash_set(u32 *mask, const u8 *addr) 232 { 233 int n = ether_crc(ETH_ALEN, addr) >> 26; 234 mask[n >> 5] |= (1 << (n & 31)); 235 } 236 237 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) 238 { 239 int n = ether_crc(ETH_ALEN, addr) >> 26; 240 return mask[n >> 5] & (1 << (n & 31)); 241 } 242 243 static int update_filter(struct tap_filter *filter, void __user *arg) 244 { 245 struct { u8 u[ETH_ALEN]; } *addr; 246 struct tun_filter uf; 247 int err, alen, n, nexact; 248 249 if (copy_from_user(&uf, arg, sizeof(uf))) 250 return -EFAULT; 251 252 if (!uf.count) { 253 /* Disabled */ 254 filter->count = 0; 255 return 0; 256 } 257 258 alen = ETH_ALEN * uf.count; 259 addr = kmalloc(alen, GFP_KERNEL); 260 if (!addr) 261 return -ENOMEM; 262 263 if (copy_from_user(addr, arg + sizeof(uf), alen)) { 264 err = -EFAULT; 265 goto done; 266 } 267 268 /* The filter is updated without holding any locks. Which is 269 * perfectly safe. We disable it first and in the worst 270 * case we'll accept a few undesired packets. */ 271 filter->count = 0; 272 wmb(); 273 274 /* Use first set of addresses as an exact filter */ 275 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) 276 memcpy(filter->addr[n], addr[n].u, ETH_ALEN); 277 278 nexact = n; 279 280 /* Remaining multicast addresses are hashed, 281 * unicast will leave the filter disabled. */ 282 memset(filter->mask, 0, sizeof(filter->mask)); 283 for (; n < uf.count; n++) { 284 if (!is_multicast_ether_addr(addr[n].u)) { 285 err = 0; /* no filter */ 286 goto done; 287 } 288 addr_hash_set(filter->mask, addr[n].u); 289 } 290 291 /* For ALLMULTI just set the mask to all ones. 292 * This overrides the mask populated above. */ 293 if ((uf.flags & TUN_FLT_ALLMULTI)) 294 memset(filter->mask, ~0, sizeof(filter->mask)); 295 296 /* Now enable the filter */ 297 wmb(); 298 filter->count = nexact; 299 300 /* Return the number of exact filters */ 301 err = nexact; 302 303 done: 304 kfree(addr); 305 return err; 306 } 307 308 /* Returns: 0 - drop, !=0 - accept */ 309 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) 310 { 311 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect 312 * at this point. */ 313 struct ethhdr *eh = (struct ethhdr *) skb->data; 314 int i; 315 316 /* Exact match */ 317 for (i = 0; i < filter->count; i++) 318 if (ether_addr_equal(eh->h_dest, filter->addr[i])) 319 return 1; 320 321 /* Inexact match (multicast only) */ 322 if (is_multicast_ether_addr(eh->h_dest)) 323 return addr_hash_test(filter->mask, eh->h_dest); 324 325 return 0; 326 } 327 328 /* 329 * Checks whether the packet is accepted or not. 330 * Returns: 0 - drop, !=0 - accept 331 */ 332 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) 333 { 334 if (!filter->count) 335 return 1; 336 337 return run_filter(filter, skb); 338 } 339 340 /* Network device part of the driver */ 341 342 static const struct ethtool_ops tun_ethtool_ops; 343 344 /* Net device detach from fd. */ 345 static void tun_net_uninit(struct net_device *dev) 346 { 347 struct tun_struct *tun = netdev_priv(dev); 348 struct tun_file *tfile = tun->tfile; 349 350 /* Inform the methods they need to stop using the dev. 351 */ 352 if (tfile) { 353 wake_up_all(&tun->wq.wait); 354 if (atomic_dec_and_test(&tfile->count)) 355 __tun_detach(tun); 356 } 357 } 358 359 static void tun_free_netdev(struct net_device *dev) 360 { 361 struct tun_struct *tun = netdev_priv(dev); 362 363 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags)); 364 365 sk_release_kernel(tun->socket.sk); 366 } 367 368 /* Net device open. */ 369 static int tun_net_open(struct net_device *dev) 370 { 371 netif_start_queue(dev); 372 return 0; 373 } 374 375 /* Net device close. */ 376 static int tun_net_close(struct net_device *dev) 377 { 378 netif_stop_queue(dev); 379 return 0; 380 } 381 382 /* Net device start xmit */ 383 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 384 { 385 struct tun_struct *tun = netdev_priv(dev); 386 387 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); 388 389 /* Drop packet if interface is not attached */ 390 if (!tun->tfile) 391 goto drop; 392 393 /* Drop if the filter does not like it. 394 * This is a noop if the filter is disabled. 395 * Filter can be enabled only for the TAP devices. */ 396 if (!check_filter(&tun->txflt, skb)) 397 goto drop; 398 399 if (tun->socket.sk->sk_filter && 400 sk_filter(tun->socket.sk, skb)) 401 goto drop; 402 403 if (skb_queue_len(&tun->socket.sk->sk_receive_queue) >= dev->tx_queue_len) { 404 if (!(tun->flags & TUN_ONE_QUEUE)) { 405 /* Normal queueing mode. */ 406 /* Packet scheduler handles dropping of further packets. */ 407 netif_stop_queue(dev); 408 409 /* We won't see all dropped packets individually, so overrun 410 * error is more appropriate. */ 411 dev->stats.tx_fifo_errors++; 412 } else { 413 /* Single queue mode. 414 * Driver handles dropping of all packets itself. */ 415 goto drop; 416 } 417 } 418 419 /* Orphan the skb - required as we might hang on to it 420 * for indefinite time. */ 421 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) 422 goto drop; 423 skb_orphan(skb); 424 425 /* Enqueue packet */ 426 skb_queue_tail(&tun->socket.sk->sk_receive_queue, skb); 427 428 /* Notify and wake up reader process */ 429 if (tun->flags & TUN_FASYNC) 430 kill_fasync(&tun->fasync, SIGIO, POLL_IN); 431 wake_up_interruptible_poll(&tun->wq.wait, POLLIN | 432 POLLRDNORM | POLLRDBAND); 433 return NETDEV_TX_OK; 434 435 drop: 436 dev->stats.tx_dropped++; 437 kfree_skb(skb); 438 return NETDEV_TX_OK; 439 } 440 441 static void tun_net_mclist(struct net_device *dev) 442 { 443 /* 444 * This callback is supposed to deal with mc filter in 445 * _rx_ path and has nothing to do with the _tx_ path. 446 * In rx path we always accept everything userspace gives us. 447 */ 448 } 449 450 #define MIN_MTU 68 451 #define MAX_MTU 65535 452 453 static int 454 tun_net_change_mtu(struct net_device *dev, int new_mtu) 455 { 456 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) 457 return -EINVAL; 458 dev->mtu = new_mtu; 459 return 0; 460 } 461 462 static netdev_features_t tun_net_fix_features(struct net_device *dev, 463 netdev_features_t features) 464 { 465 struct tun_struct *tun = netdev_priv(dev); 466 467 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); 468 } 469 #ifdef CONFIG_NET_POLL_CONTROLLER 470 static void tun_poll_controller(struct net_device *dev) 471 { 472 /* 473 * Tun only receives frames when: 474 * 1) the char device endpoint gets data from user space 475 * 2) the tun socket gets a sendmsg call from user space 476 * Since both of those are syncronous operations, we are guaranteed 477 * never to have pending data when we poll for it 478 * so theres nothing to do here but return. 479 * We need this though so netpoll recognizes us as an interface that 480 * supports polling, which enables bridge devices in virt setups to 481 * still use netconsole 482 */ 483 return; 484 } 485 #endif 486 static const struct net_device_ops tun_netdev_ops = { 487 .ndo_uninit = tun_net_uninit, 488 .ndo_open = tun_net_open, 489 .ndo_stop = tun_net_close, 490 .ndo_start_xmit = tun_net_xmit, 491 .ndo_change_mtu = tun_net_change_mtu, 492 .ndo_fix_features = tun_net_fix_features, 493 #ifdef CONFIG_NET_POLL_CONTROLLER 494 .ndo_poll_controller = tun_poll_controller, 495 #endif 496 }; 497 498 static const struct net_device_ops tap_netdev_ops = { 499 .ndo_uninit = tun_net_uninit, 500 .ndo_open = tun_net_open, 501 .ndo_stop = tun_net_close, 502 .ndo_start_xmit = tun_net_xmit, 503 .ndo_change_mtu = tun_net_change_mtu, 504 .ndo_fix_features = tun_net_fix_features, 505 .ndo_set_rx_mode = tun_net_mclist, 506 .ndo_set_mac_address = eth_mac_addr, 507 .ndo_validate_addr = eth_validate_addr, 508 #ifdef CONFIG_NET_POLL_CONTROLLER 509 .ndo_poll_controller = tun_poll_controller, 510 #endif 511 }; 512 513 /* Initialize net device. */ 514 static void tun_net_init(struct net_device *dev) 515 { 516 struct tun_struct *tun = netdev_priv(dev); 517 518 switch (tun->flags & TUN_TYPE_MASK) { 519 case TUN_TUN_DEV: 520 dev->netdev_ops = &tun_netdev_ops; 521 522 /* Point-to-Point TUN Device */ 523 dev->hard_header_len = 0; 524 dev->addr_len = 0; 525 dev->mtu = 1500; 526 527 /* Zero header length */ 528 dev->type = ARPHRD_NONE; 529 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 530 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 531 break; 532 533 case TUN_TAP_DEV: 534 dev->netdev_ops = &tap_netdev_ops; 535 /* Ethernet TAP Device */ 536 ether_setup(dev); 537 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 538 539 eth_hw_addr_random(dev); 540 541 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ 542 break; 543 } 544 } 545 546 /* Character device part */ 547 548 /* Poll */ 549 static unsigned int tun_chr_poll(struct file *file, poll_table * wait) 550 { 551 struct tun_file *tfile = file->private_data; 552 struct tun_struct *tun = __tun_get(tfile); 553 struct sock *sk; 554 unsigned int mask = 0; 555 556 if (!tun) 557 return POLLERR; 558 559 sk = tun->socket.sk; 560 561 tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); 562 563 poll_wait(file, &tun->wq.wait, wait); 564 565 if (!skb_queue_empty(&sk->sk_receive_queue)) 566 mask |= POLLIN | POLLRDNORM; 567 568 if (sock_writeable(sk) || 569 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && 570 sock_writeable(sk))) 571 mask |= POLLOUT | POLLWRNORM; 572 573 if (tun->dev->reg_state != NETREG_REGISTERED) 574 mask = POLLERR; 575 576 tun_put(tun); 577 return mask; 578 } 579 580 /* prepad is the amount to reserve at front. len is length after that. 581 * linear is a hint as to how much to copy (usually headers). */ 582 static struct sk_buff *tun_alloc_skb(struct tun_struct *tun, 583 size_t prepad, size_t len, 584 size_t linear, int noblock) 585 { 586 struct sock *sk = tun->socket.sk; 587 struct sk_buff *skb; 588 int err; 589 590 sock_update_classid(sk); 591 592 /* Under a page? Don't bother with paged skb. */ 593 if (prepad + len < PAGE_SIZE || !linear) 594 linear = len; 595 596 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 597 &err); 598 if (!skb) 599 return ERR_PTR(err); 600 601 skb_reserve(skb, prepad); 602 skb_put(skb, linear); 603 skb->data_len = len - linear; 604 skb->len += len - linear; 605 606 return skb; 607 } 608 609 /* set skb frags from iovec, this can move to core network code for reuse */ 610 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, 611 int offset, size_t count) 612 { 613 int len = iov_length(from, count) - offset; 614 int copy = skb_headlen(skb); 615 int size, offset1 = 0; 616 int i = 0; 617 618 /* Skip over from offset */ 619 while (count && (offset >= from->iov_len)) { 620 offset -= from->iov_len; 621 ++from; 622 --count; 623 } 624 625 /* copy up to skb headlen */ 626 while (count && (copy > 0)) { 627 size = min_t(unsigned int, copy, from->iov_len - offset); 628 if (copy_from_user(skb->data + offset1, from->iov_base + offset, 629 size)) 630 return -EFAULT; 631 if (copy > size) { 632 ++from; 633 --count; 634 offset = 0; 635 } else 636 offset += size; 637 copy -= size; 638 offset1 += size; 639 } 640 641 if (len == offset1) 642 return 0; 643 644 while (count--) { 645 struct page *page[MAX_SKB_FRAGS]; 646 int num_pages; 647 unsigned long base; 648 unsigned long truesize; 649 650 len = from->iov_len - offset; 651 if (!len) { 652 offset = 0; 653 ++from; 654 continue; 655 } 656 base = (unsigned long)from->iov_base + offset; 657 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; 658 if (i + size > MAX_SKB_FRAGS) 659 return -EMSGSIZE; 660 num_pages = get_user_pages_fast(base, size, 0, &page[i]); 661 if (num_pages != size) { 662 for (i = 0; i < num_pages; i++) 663 put_page(page[i]); 664 return -EFAULT; 665 } 666 truesize = size * PAGE_SIZE; 667 skb->data_len += len; 668 skb->len += len; 669 skb->truesize += truesize; 670 atomic_add(truesize, &skb->sk->sk_wmem_alloc); 671 while (len) { 672 int off = base & ~PAGE_MASK; 673 int size = min_t(int, len, PAGE_SIZE - off); 674 __skb_fill_page_desc(skb, i, page[i], off, size); 675 skb_shinfo(skb)->nr_frags++; 676 /* increase sk_wmem_alloc */ 677 base += size; 678 len -= size; 679 i++; 680 } 681 offset = 0; 682 ++from; 683 } 684 return 0; 685 } 686 687 /* Get packet from user space buffer */ 688 static ssize_t tun_get_user(struct tun_struct *tun, void *msg_control, 689 const struct iovec *iv, size_t total_len, 690 size_t count, int noblock) 691 { 692 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; 693 struct sk_buff *skb; 694 size_t len = total_len, align = NET_SKB_PAD; 695 struct virtio_net_hdr gso = { 0 }; 696 int offset = 0; 697 int copylen; 698 bool zerocopy = false; 699 int err; 700 701 if (!(tun->flags & TUN_NO_PI)) { 702 if ((len -= sizeof(pi)) > total_len) 703 return -EINVAL; 704 705 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) 706 return -EFAULT; 707 offset += sizeof(pi); 708 } 709 710 if (tun->flags & TUN_VNET_HDR) { 711 if ((len -= tun->vnet_hdr_sz) > total_len) 712 return -EINVAL; 713 714 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) 715 return -EFAULT; 716 717 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 718 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) 719 gso.hdr_len = gso.csum_start + gso.csum_offset + 2; 720 721 if (gso.hdr_len > len) 722 return -EINVAL; 723 offset += tun->vnet_hdr_sz; 724 } 725 726 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { 727 align += NET_IP_ALIGN; 728 if (unlikely(len < ETH_HLEN || 729 (gso.hdr_len && gso.hdr_len < ETH_HLEN))) 730 return -EINVAL; 731 } 732 733 if (msg_control) 734 zerocopy = true; 735 736 if (zerocopy) { 737 /* Userspace may produce vectors with count greater than 738 * MAX_SKB_FRAGS, so we need to linearize parts of the skb 739 * to let the rest of data to be fit in the frags. 740 */ 741 if (count > MAX_SKB_FRAGS) { 742 copylen = iov_length(iv, count - MAX_SKB_FRAGS); 743 if (copylen < offset) 744 copylen = 0; 745 else 746 copylen -= offset; 747 } else 748 copylen = 0; 749 /* There are 256 bytes to be copied in skb, so there is enough 750 * room for skb expand head in case it is used. 751 * The rest of the buffer is mapped from userspace. 752 */ 753 if (copylen < gso.hdr_len) 754 copylen = gso.hdr_len; 755 if (!copylen) 756 copylen = GOODCOPY_LEN; 757 } else 758 copylen = len; 759 760 skb = tun_alloc_skb(tun, align, copylen, gso.hdr_len, noblock); 761 if (IS_ERR(skb)) { 762 if (PTR_ERR(skb) != -EAGAIN) 763 tun->dev->stats.rx_dropped++; 764 return PTR_ERR(skb); 765 } 766 767 if (zerocopy) 768 err = zerocopy_sg_from_iovec(skb, iv, offset, count); 769 else 770 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len); 771 772 if (err) { 773 tun->dev->stats.rx_dropped++; 774 kfree_skb(skb); 775 return -EFAULT; 776 } 777 778 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 779 if (!skb_partial_csum_set(skb, gso.csum_start, 780 gso.csum_offset)) { 781 tun->dev->stats.rx_frame_errors++; 782 kfree_skb(skb); 783 return -EINVAL; 784 } 785 } 786 787 switch (tun->flags & TUN_TYPE_MASK) { 788 case TUN_TUN_DEV: 789 if (tun->flags & TUN_NO_PI) { 790 switch (skb->data[0] & 0xf0) { 791 case 0x40: 792 pi.proto = htons(ETH_P_IP); 793 break; 794 case 0x60: 795 pi.proto = htons(ETH_P_IPV6); 796 break; 797 default: 798 tun->dev->stats.rx_dropped++; 799 kfree_skb(skb); 800 return -EINVAL; 801 } 802 } 803 804 skb_reset_mac_header(skb); 805 skb->protocol = pi.proto; 806 skb->dev = tun->dev; 807 break; 808 case TUN_TAP_DEV: 809 skb->protocol = eth_type_trans(skb, tun->dev); 810 break; 811 } 812 813 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { 814 pr_debug("GSO!\n"); 815 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 816 case VIRTIO_NET_HDR_GSO_TCPV4: 817 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 818 break; 819 case VIRTIO_NET_HDR_GSO_TCPV6: 820 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 821 break; 822 case VIRTIO_NET_HDR_GSO_UDP: 823 skb_shinfo(skb)->gso_type = SKB_GSO_UDP; 824 break; 825 default: 826 tun->dev->stats.rx_frame_errors++; 827 kfree_skb(skb); 828 return -EINVAL; 829 } 830 831 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) 832 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 833 834 skb_shinfo(skb)->gso_size = gso.gso_size; 835 if (skb_shinfo(skb)->gso_size == 0) { 836 tun->dev->stats.rx_frame_errors++; 837 kfree_skb(skb); 838 return -EINVAL; 839 } 840 841 /* Header must be checked, and gso_segs computed. */ 842 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 843 skb_shinfo(skb)->gso_segs = 0; 844 } 845 846 /* copy skb_ubuf_info for callback when skb has no error */ 847 if (zerocopy) { 848 skb_shinfo(skb)->destructor_arg = msg_control; 849 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 850 } 851 852 netif_rx_ni(skb); 853 854 tun->dev->stats.rx_packets++; 855 tun->dev->stats.rx_bytes += len; 856 857 return total_len; 858 } 859 860 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 861 unsigned long count, loff_t pos) 862 { 863 struct file *file = iocb->ki_filp; 864 struct tun_struct *tun = tun_get(file); 865 ssize_t result; 866 867 if (!tun) 868 return -EBADFD; 869 870 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count); 871 872 result = tun_get_user(tun, NULL, iv, iov_length(iv, count), count, 873 file->f_flags & O_NONBLOCK); 874 875 tun_put(tun); 876 return result; 877 } 878 879 /* Put packet to the user space buffer */ 880 static ssize_t tun_put_user(struct tun_struct *tun, 881 struct sk_buff *skb, 882 const struct iovec *iv, int len) 883 { 884 struct tun_pi pi = { 0, skb->protocol }; 885 ssize_t total = 0; 886 887 if (!(tun->flags & TUN_NO_PI)) { 888 if ((len -= sizeof(pi)) < 0) 889 return -EINVAL; 890 891 if (len < skb->len) { 892 /* Packet will be striped */ 893 pi.flags |= TUN_PKT_STRIP; 894 } 895 896 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi))) 897 return -EFAULT; 898 total += sizeof(pi); 899 } 900 901 if (tun->flags & TUN_VNET_HDR) { 902 struct virtio_net_hdr gso = { 0 }; /* no info leak */ 903 if ((len -= tun->vnet_hdr_sz) < 0) 904 return -EINVAL; 905 906 if (skb_is_gso(skb)) { 907 struct skb_shared_info *sinfo = skb_shinfo(skb); 908 909 /* This is a hint as to how much should be linear. */ 910 gso.hdr_len = skb_headlen(skb); 911 gso.gso_size = sinfo->gso_size; 912 if (sinfo->gso_type & SKB_GSO_TCPV4) 913 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 914 else if (sinfo->gso_type & SKB_GSO_TCPV6) 915 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 916 else if (sinfo->gso_type & SKB_GSO_UDP) 917 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; 918 else { 919 pr_err("unexpected GSO type: " 920 "0x%x, gso_size %d, hdr_len %d\n", 921 sinfo->gso_type, gso.gso_size, 922 gso.hdr_len); 923 print_hex_dump(KERN_ERR, "tun: ", 924 DUMP_PREFIX_NONE, 925 16, 1, skb->head, 926 min((int)gso.hdr_len, 64), true); 927 WARN_ON_ONCE(1); 928 return -EINVAL; 929 } 930 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 931 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; 932 } else 933 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; 934 935 if (skb->ip_summed == CHECKSUM_PARTIAL) { 936 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 937 gso.csum_start = skb_checksum_start_offset(skb); 938 gso.csum_offset = skb->csum_offset; 939 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 940 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; 941 } /* else everything is zero */ 942 943 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, 944 sizeof(gso)))) 945 return -EFAULT; 946 total += tun->vnet_hdr_sz; 947 } 948 949 len = min_t(int, skb->len, len); 950 951 skb_copy_datagram_const_iovec(skb, 0, iv, total, len); 952 total += skb->len; 953 954 tun->dev->stats.tx_packets++; 955 tun->dev->stats.tx_bytes += len; 956 957 return total; 958 } 959 960 static ssize_t tun_do_read(struct tun_struct *tun, 961 struct kiocb *iocb, const struct iovec *iv, 962 ssize_t len, int noblock) 963 { 964 DECLARE_WAITQUEUE(wait, current); 965 struct sk_buff *skb; 966 ssize_t ret = 0; 967 968 tun_debug(KERN_INFO, tun, "tun_chr_read\n"); 969 970 if (unlikely(!noblock)) 971 add_wait_queue(&tun->wq.wait, &wait); 972 while (len) { 973 current->state = TASK_INTERRUPTIBLE; 974 975 /* Read frames from the queue */ 976 if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) { 977 if (noblock) { 978 ret = -EAGAIN; 979 break; 980 } 981 if (signal_pending(current)) { 982 ret = -ERESTARTSYS; 983 break; 984 } 985 if (tun->dev->reg_state != NETREG_REGISTERED) { 986 ret = -EIO; 987 break; 988 } 989 990 /* Nothing to read, let's sleep */ 991 schedule(); 992 continue; 993 } 994 netif_wake_queue(tun->dev); 995 996 ret = tun_put_user(tun, skb, iv, len); 997 kfree_skb(skb); 998 break; 999 } 1000 1001 current->state = TASK_RUNNING; 1002 if (unlikely(!noblock)) 1003 remove_wait_queue(&tun->wq.wait, &wait); 1004 1005 return ret; 1006 } 1007 1008 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 1009 unsigned long count, loff_t pos) 1010 { 1011 struct file *file = iocb->ki_filp; 1012 struct tun_file *tfile = file->private_data; 1013 struct tun_struct *tun = __tun_get(tfile); 1014 ssize_t len, ret; 1015 1016 if (!tun) 1017 return -EBADFD; 1018 len = iov_length(iv, count); 1019 if (len < 0) { 1020 ret = -EINVAL; 1021 goto out; 1022 } 1023 1024 ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK); 1025 ret = min_t(ssize_t, ret, len); 1026 out: 1027 tun_put(tun); 1028 return ret; 1029 } 1030 1031 static void tun_setup(struct net_device *dev) 1032 { 1033 struct tun_struct *tun = netdev_priv(dev); 1034 1035 tun->owner = INVALID_UID; 1036 tun->group = INVALID_GID; 1037 1038 dev->ethtool_ops = &tun_ethtool_ops; 1039 dev->destructor = tun_free_netdev; 1040 } 1041 1042 /* Trivial set of netlink ops to allow deleting tun or tap 1043 * device with netlink. 1044 */ 1045 static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) 1046 { 1047 return -EINVAL; 1048 } 1049 1050 static struct rtnl_link_ops tun_link_ops __read_mostly = { 1051 .kind = DRV_NAME, 1052 .priv_size = sizeof(struct tun_struct), 1053 .setup = tun_setup, 1054 .validate = tun_validate, 1055 }; 1056 1057 static void tun_sock_write_space(struct sock *sk) 1058 { 1059 struct tun_struct *tun; 1060 wait_queue_head_t *wqueue; 1061 1062 if (!sock_writeable(sk)) 1063 return; 1064 1065 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 1066 return; 1067 1068 wqueue = sk_sleep(sk); 1069 if (wqueue && waitqueue_active(wqueue)) 1070 wake_up_interruptible_sync_poll(wqueue, POLLOUT | 1071 POLLWRNORM | POLLWRBAND); 1072 1073 tun = tun_sk(sk)->tun; 1074 kill_fasync(&tun->fasync, SIGIO, POLL_OUT); 1075 } 1076 1077 static void tun_sock_destruct(struct sock *sk) 1078 { 1079 free_netdev(tun_sk(sk)->tun->dev); 1080 } 1081 1082 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, 1083 struct msghdr *m, size_t total_len) 1084 { 1085 struct tun_struct *tun = container_of(sock, struct tun_struct, socket); 1086 return tun_get_user(tun, m->msg_control, m->msg_iov, total_len, 1087 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); 1088 } 1089 1090 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, 1091 struct msghdr *m, size_t total_len, 1092 int flags) 1093 { 1094 struct tun_struct *tun = container_of(sock, struct tun_struct, socket); 1095 int ret; 1096 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) 1097 return -EINVAL; 1098 ret = tun_do_read(tun, iocb, m->msg_iov, total_len, 1099 flags & MSG_DONTWAIT); 1100 if (ret > total_len) { 1101 m->msg_flags |= MSG_TRUNC; 1102 ret = flags & MSG_TRUNC ? ret : total_len; 1103 } 1104 return ret; 1105 } 1106 1107 static int tun_release(struct socket *sock) 1108 { 1109 if (sock->sk) 1110 sock_put(sock->sk); 1111 return 0; 1112 } 1113 1114 /* Ops structure to mimic raw sockets with tun */ 1115 static const struct proto_ops tun_socket_ops = { 1116 .sendmsg = tun_sendmsg, 1117 .recvmsg = tun_recvmsg, 1118 .release = tun_release, 1119 }; 1120 1121 static struct proto tun_proto = { 1122 .name = "tun", 1123 .owner = THIS_MODULE, 1124 .obj_size = sizeof(struct tun_sock), 1125 }; 1126 1127 static int tun_flags(struct tun_struct *tun) 1128 { 1129 int flags = 0; 1130 1131 if (tun->flags & TUN_TUN_DEV) 1132 flags |= IFF_TUN; 1133 else 1134 flags |= IFF_TAP; 1135 1136 if (tun->flags & TUN_NO_PI) 1137 flags |= IFF_NO_PI; 1138 1139 if (tun->flags & TUN_ONE_QUEUE) 1140 flags |= IFF_ONE_QUEUE; 1141 1142 if (tun->flags & TUN_VNET_HDR) 1143 flags |= IFF_VNET_HDR; 1144 1145 return flags; 1146 } 1147 1148 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, 1149 char *buf) 1150 { 1151 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1152 return sprintf(buf, "0x%x\n", tun_flags(tun)); 1153 } 1154 1155 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, 1156 char *buf) 1157 { 1158 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1159 return uid_valid(tun->owner)? 1160 sprintf(buf, "%u\n", 1161 from_kuid_munged(current_user_ns(), tun->owner)): 1162 sprintf(buf, "-1\n"); 1163 } 1164 1165 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, 1166 char *buf) 1167 { 1168 struct tun_struct *tun = netdev_priv(to_net_dev(dev)); 1169 return gid_valid(tun->group) ? 1170 sprintf(buf, "%u\n", 1171 from_kgid_munged(current_user_ns(), tun->group)): 1172 sprintf(buf, "-1\n"); 1173 } 1174 1175 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); 1176 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); 1177 static DEVICE_ATTR(group, 0444, tun_show_group, NULL); 1178 1179 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 1180 { 1181 struct sock *sk; 1182 struct tun_struct *tun; 1183 struct net_device *dev; 1184 int err; 1185 1186 dev = __dev_get_by_name(net, ifr->ifr_name); 1187 if (dev) { 1188 const struct cred *cred = current_cred(); 1189 1190 if (ifr->ifr_flags & IFF_TUN_EXCL) 1191 return -EBUSY; 1192 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) 1193 tun = netdev_priv(dev); 1194 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) 1195 tun = netdev_priv(dev); 1196 else 1197 return -EINVAL; 1198 1199 if (((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || 1200 (gid_valid(tun->group) && !in_egroup_p(tun->group))) && 1201 !capable(CAP_NET_ADMIN)) 1202 return -EPERM; 1203 err = security_tun_dev_attach(tun->socket.sk); 1204 if (err < 0) 1205 return err; 1206 1207 err = tun_attach(tun, file); 1208 if (err < 0) 1209 return err; 1210 } 1211 else { 1212 char *name; 1213 unsigned long flags = 0; 1214 1215 if (!capable(CAP_NET_ADMIN)) 1216 return -EPERM; 1217 err = security_tun_dev_create(); 1218 if (err < 0) 1219 return err; 1220 1221 /* Set dev type */ 1222 if (ifr->ifr_flags & IFF_TUN) { 1223 /* TUN device */ 1224 flags |= TUN_TUN_DEV; 1225 name = "tun%d"; 1226 } else if (ifr->ifr_flags & IFF_TAP) { 1227 /* TAP device */ 1228 flags |= TUN_TAP_DEV; 1229 name = "tap%d"; 1230 } else 1231 return -EINVAL; 1232 1233 if (*ifr->ifr_name) 1234 name = ifr->ifr_name; 1235 1236 dev = alloc_netdev(sizeof(struct tun_struct), name, 1237 tun_setup); 1238 if (!dev) 1239 return -ENOMEM; 1240 1241 dev_net_set(dev, net); 1242 dev->rtnl_link_ops = &tun_link_ops; 1243 1244 tun = netdev_priv(dev); 1245 tun->dev = dev; 1246 tun->flags = flags; 1247 tun->txflt.count = 0; 1248 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 1249 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags); 1250 1251 err = -ENOMEM; 1252 sk = sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, &tun_proto); 1253 if (!sk) 1254 goto err_free_dev; 1255 1256 sk_change_net(sk, net); 1257 tun->socket.wq = &tun->wq; 1258 init_waitqueue_head(&tun->wq.wait); 1259 tun->socket.ops = &tun_socket_ops; 1260 sock_init_data(&tun->socket, sk); 1261 sk->sk_write_space = tun_sock_write_space; 1262 sk->sk_sndbuf = INT_MAX; 1263 sock_set_flag(sk, SOCK_ZEROCOPY); 1264 1265 tun_sk(sk)->tun = tun; 1266 1267 security_tun_dev_post_create(sk); 1268 1269 tun_net_init(dev); 1270 1271 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | 1272 TUN_USER_FEATURES; 1273 dev->features = dev->hw_features; 1274 1275 err = register_netdevice(tun->dev); 1276 if (err < 0) 1277 goto err_free_sk; 1278 1279 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || 1280 device_create_file(&tun->dev->dev, &dev_attr_owner) || 1281 device_create_file(&tun->dev->dev, &dev_attr_group)) 1282 pr_err("Failed to create tun sysfs files\n"); 1283 1284 sk->sk_destruct = tun_sock_destruct; 1285 1286 err = tun_attach(tun, file); 1287 if (err < 0) 1288 goto failed; 1289 } 1290 1291 tun_debug(KERN_INFO, tun, "tun_set_iff\n"); 1292 1293 if (ifr->ifr_flags & IFF_NO_PI) 1294 tun->flags |= TUN_NO_PI; 1295 else 1296 tun->flags &= ~TUN_NO_PI; 1297 1298 if (ifr->ifr_flags & IFF_ONE_QUEUE) 1299 tun->flags |= TUN_ONE_QUEUE; 1300 else 1301 tun->flags &= ~TUN_ONE_QUEUE; 1302 1303 if (ifr->ifr_flags & IFF_VNET_HDR) 1304 tun->flags |= TUN_VNET_HDR; 1305 else 1306 tun->flags &= ~TUN_VNET_HDR; 1307 1308 /* Make sure persistent devices do not get stuck in 1309 * xoff state. 1310 */ 1311 if (netif_running(tun->dev)) 1312 netif_wake_queue(tun->dev); 1313 1314 strcpy(ifr->ifr_name, tun->dev->name); 1315 return 0; 1316 1317 err_free_sk: 1318 tun_free_netdev(dev); 1319 err_free_dev: 1320 free_netdev(dev); 1321 failed: 1322 return err; 1323 } 1324 1325 static int tun_get_iff(struct net *net, struct tun_struct *tun, 1326 struct ifreq *ifr) 1327 { 1328 tun_debug(KERN_INFO, tun, "tun_get_iff\n"); 1329 1330 strcpy(ifr->ifr_name, tun->dev->name); 1331 1332 ifr->ifr_flags = tun_flags(tun); 1333 1334 return 0; 1335 } 1336 1337 /* This is like a cut-down ethtool ops, except done via tun fd so no 1338 * privs required. */ 1339 static int set_offload(struct tun_struct *tun, unsigned long arg) 1340 { 1341 netdev_features_t features = 0; 1342 1343 if (arg & TUN_F_CSUM) { 1344 features |= NETIF_F_HW_CSUM; 1345 arg &= ~TUN_F_CSUM; 1346 1347 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { 1348 if (arg & TUN_F_TSO_ECN) { 1349 features |= NETIF_F_TSO_ECN; 1350 arg &= ~TUN_F_TSO_ECN; 1351 } 1352 if (arg & TUN_F_TSO4) 1353 features |= NETIF_F_TSO; 1354 if (arg & TUN_F_TSO6) 1355 features |= NETIF_F_TSO6; 1356 arg &= ~(TUN_F_TSO4|TUN_F_TSO6); 1357 } 1358 1359 if (arg & TUN_F_UFO) { 1360 features |= NETIF_F_UFO; 1361 arg &= ~TUN_F_UFO; 1362 } 1363 } 1364 1365 /* This gives the user a way to test for new features in future by 1366 * trying to set them. */ 1367 if (arg) 1368 return -EINVAL; 1369 1370 tun->set_features = features; 1371 netdev_update_features(tun->dev); 1372 1373 return 0; 1374 } 1375 1376 static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 1377 unsigned long arg, int ifreq_len) 1378 { 1379 struct tun_file *tfile = file->private_data; 1380 struct tun_struct *tun; 1381 void __user* argp = (void __user*)arg; 1382 struct sock_fprog fprog; 1383 struct ifreq ifr; 1384 kuid_t owner; 1385 kgid_t group; 1386 int sndbuf; 1387 int vnet_hdr_sz; 1388 int ret; 1389 1390 if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) { 1391 if (copy_from_user(&ifr, argp, ifreq_len)) 1392 return -EFAULT; 1393 } else { 1394 memset(&ifr, 0, sizeof(ifr)); 1395 } 1396 if (cmd == TUNGETFEATURES) { 1397 /* Currently this just means: "what IFF flags are valid?". 1398 * This is needed because we never checked for invalid flags on 1399 * TUNSETIFF. */ 1400 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | 1401 IFF_VNET_HDR, 1402 (unsigned int __user*)argp); 1403 } 1404 1405 rtnl_lock(); 1406 1407 tun = __tun_get(tfile); 1408 if (cmd == TUNSETIFF && !tun) { 1409 ifr.ifr_name[IFNAMSIZ-1] = '\0'; 1410 1411 ret = tun_set_iff(tfile->net, file, &ifr); 1412 1413 if (ret) 1414 goto unlock; 1415 1416 if (copy_to_user(argp, &ifr, ifreq_len)) 1417 ret = -EFAULT; 1418 goto unlock; 1419 } 1420 1421 ret = -EBADFD; 1422 if (!tun) 1423 goto unlock; 1424 1425 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %d\n", cmd); 1426 1427 ret = 0; 1428 switch (cmd) { 1429 case TUNGETIFF: 1430 ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr); 1431 if (ret) 1432 break; 1433 1434 if (copy_to_user(argp, &ifr, ifreq_len)) 1435 ret = -EFAULT; 1436 break; 1437 1438 case TUNSETNOCSUM: 1439 /* Disable/Enable checksum */ 1440 1441 /* [unimplemented] */ 1442 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", 1443 arg ? "disabled" : "enabled"); 1444 break; 1445 1446 case TUNSETPERSIST: 1447 /* Disable/Enable persist mode */ 1448 if (arg) 1449 tun->flags |= TUN_PERSIST; 1450 else 1451 tun->flags &= ~TUN_PERSIST; 1452 1453 tun_debug(KERN_INFO, tun, "persist %s\n", 1454 arg ? "enabled" : "disabled"); 1455 break; 1456 1457 case TUNSETOWNER: 1458 /* Set owner of the device */ 1459 owner = make_kuid(current_user_ns(), arg); 1460 if (!uid_valid(owner)) { 1461 ret = -EINVAL; 1462 break; 1463 } 1464 tun->owner = owner; 1465 tun_debug(KERN_INFO, tun, "owner set to %d\n", 1466 from_kuid(&init_user_ns, tun->owner)); 1467 break; 1468 1469 case TUNSETGROUP: 1470 /* Set group of the device */ 1471 group = make_kgid(current_user_ns(), arg); 1472 if (!gid_valid(group)) { 1473 ret = -EINVAL; 1474 break; 1475 } 1476 tun->group = group; 1477 tun_debug(KERN_INFO, tun, "group set to %d\n", 1478 from_kgid(&init_user_ns, tun->group)); 1479 break; 1480 1481 case TUNSETLINK: 1482 /* Only allow setting the type when the interface is down */ 1483 if (tun->dev->flags & IFF_UP) { 1484 tun_debug(KERN_INFO, tun, 1485 "Linktype set failed because interface is up\n"); 1486 ret = -EBUSY; 1487 } else { 1488 tun->dev->type = (int) arg; 1489 tun_debug(KERN_INFO, tun, "linktype set to %d\n", 1490 tun->dev->type); 1491 ret = 0; 1492 } 1493 break; 1494 1495 #ifdef TUN_DEBUG 1496 case TUNSETDEBUG: 1497 tun->debug = arg; 1498 break; 1499 #endif 1500 case TUNSETOFFLOAD: 1501 ret = set_offload(tun, arg); 1502 break; 1503 1504 case TUNSETTXFILTER: 1505 /* Can be set only for TAPs */ 1506 ret = -EINVAL; 1507 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 1508 break; 1509 ret = update_filter(&tun->txflt, (void __user *)arg); 1510 break; 1511 1512 case SIOCGIFHWADDR: 1513 /* Get hw address */ 1514 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); 1515 ifr.ifr_hwaddr.sa_family = tun->dev->type; 1516 if (copy_to_user(argp, &ifr, ifreq_len)) 1517 ret = -EFAULT; 1518 break; 1519 1520 case SIOCSIFHWADDR: 1521 /* Set hw address */ 1522 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", 1523 ifr.ifr_hwaddr.sa_data); 1524 1525 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); 1526 break; 1527 1528 case TUNGETSNDBUF: 1529 sndbuf = tun->socket.sk->sk_sndbuf; 1530 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) 1531 ret = -EFAULT; 1532 break; 1533 1534 case TUNSETSNDBUF: 1535 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { 1536 ret = -EFAULT; 1537 break; 1538 } 1539 1540 tun->socket.sk->sk_sndbuf = sndbuf; 1541 break; 1542 1543 case TUNGETVNETHDRSZ: 1544 vnet_hdr_sz = tun->vnet_hdr_sz; 1545 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) 1546 ret = -EFAULT; 1547 break; 1548 1549 case TUNSETVNETHDRSZ: 1550 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { 1551 ret = -EFAULT; 1552 break; 1553 } 1554 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { 1555 ret = -EINVAL; 1556 break; 1557 } 1558 1559 tun->vnet_hdr_sz = vnet_hdr_sz; 1560 break; 1561 1562 case TUNATTACHFILTER: 1563 /* Can be set only for TAPs */ 1564 ret = -EINVAL; 1565 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 1566 break; 1567 ret = -EFAULT; 1568 if (copy_from_user(&fprog, argp, sizeof(fprog))) 1569 break; 1570 1571 ret = sk_attach_filter(&fprog, tun->socket.sk); 1572 break; 1573 1574 case TUNDETACHFILTER: 1575 /* Can be set only for TAPs */ 1576 ret = -EINVAL; 1577 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 1578 break; 1579 ret = sk_detach_filter(tun->socket.sk); 1580 break; 1581 1582 default: 1583 ret = -EINVAL; 1584 break; 1585 } 1586 1587 unlock: 1588 rtnl_unlock(); 1589 if (tun) 1590 tun_put(tun); 1591 return ret; 1592 } 1593 1594 static long tun_chr_ioctl(struct file *file, 1595 unsigned int cmd, unsigned long arg) 1596 { 1597 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); 1598 } 1599 1600 #ifdef CONFIG_COMPAT 1601 static long tun_chr_compat_ioctl(struct file *file, 1602 unsigned int cmd, unsigned long arg) 1603 { 1604 switch (cmd) { 1605 case TUNSETIFF: 1606 case TUNGETIFF: 1607 case TUNSETTXFILTER: 1608 case TUNGETSNDBUF: 1609 case TUNSETSNDBUF: 1610 case SIOCGIFHWADDR: 1611 case SIOCSIFHWADDR: 1612 arg = (unsigned long)compat_ptr(arg); 1613 break; 1614 default: 1615 arg = (compat_ulong_t)arg; 1616 break; 1617 } 1618 1619 /* 1620 * compat_ifreq is shorter than ifreq, so we must not access beyond 1621 * the end of that structure. All fields that are used in this 1622 * driver are compatible though, we don't need to convert the 1623 * contents. 1624 */ 1625 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); 1626 } 1627 #endif /* CONFIG_COMPAT */ 1628 1629 static int tun_chr_fasync(int fd, struct file *file, int on) 1630 { 1631 struct tun_struct *tun = tun_get(file); 1632 int ret; 1633 1634 if (!tun) 1635 return -EBADFD; 1636 1637 tun_debug(KERN_INFO, tun, "tun_chr_fasync %d\n", on); 1638 1639 if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0) 1640 goto out; 1641 1642 if (on) { 1643 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0); 1644 if (ret) 1645 goto out; 1646 tun->flags |= TUN_FASYNC; 1647 } else 1648 tun->flags &= ~TUN_FASYNC; 1649 ret = 0; 1650 out: 1651 tun_put(tun); 1652 return ret; 1653 } 1654 1655 static int tun_chr_open(struct inode *inode, struct file * file) 1656 { 1657 struct tun_file *tfile; 1658 1659 DBG1(KERN_INFO, "tunX: tun_chr_open\n"); 1660 1661 tfile = kmalloc(sizeof(*tfile), GFP_KERNEL); 1662 if (!tfile) 1663 return -ENOMEM; 1664 atomic_set(&tfile->count, 0); 1665 tfile->tun = NULL; 1666 tfile->net = get_net(current->nsproxy->net_ns); 1667 file->private_data = tfile; 1668 return 0; 1669 } 1670 1671 static int tun_chr_close(struct inode *inode, struct file *file) 1672 { 1673 struct tun_file *tfile = file->private_data; 1674 struct tun_struct *tun; 1675 1676 tun = __tun_get(tfile); 1677 if (tun) { 1678 struct net_device *dev = tun->dev; 1679 1680 tun_debug(KERN_INFO, tun, "tun_chr_close\n"); 1681 1682 __tun_detach(tun); 1683 1684 /* If desirable, unregister the netdevice. */ 1685 if (!(tun->flags & TUN_PERSIST)) { 1686 rtnl_lock(); 1687 if (dev->reg_state == NETREG_REGISTERED) 1688 unregister_netdevice(dev); 1689 rtnl_unlock(); 1690 } 1691 } 1692 1693 tun = tfile->tun; 1694 if (tun) 1695 sock_put(tun->socket.sk); 1696 1697 put_net(tfile->net); 1698 kfree(tfile); 1699 1700 return 0; 1701 } 1702 1703 static const struct file_operations tun_fops = { 1704 .owner = THIS_MODULE, 1705 .llseek = no_llseek, 1706 .read = do_sync_read, 1707 .aio_read = tun_chr_aio_read, 1708 .write = do_sync_write, 1709 .aio_write = tun_chr_aio_write, 1710 .poll = tun_chr_poll, 1711 .unlocked_ioctl = tun_chr_ioctl, 1712 #ifdef CONFIG_COMPAT 1713 .compat_ioctl = tun_chr_compat_ioctl, 1714 #endif 1715 .open = tun_chr_open, 1716 .release = tun_chr_close, 1717 .fasync = tun_chr_fasync 1718 }; 1719 1720 static struct miscdevice tun_miscdev = { 1721 .minor = TUN_MINOR, 1722 .name = "tun", 1723 .nodename = "net/tun", 1724 .fops = &tun_fops, 1725 }; 1726 1727 /* ethtool interface */ 1728 1729 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) 1730 { 1731 cmd->supported = 0; 1732 cmd->advertising = 0; 1733 ethtool_cmd_speed_set(cmd, SPEED_10); 1734 cmd->duplex = DUPLEX_FULL; 1735 cmd->port = PORT_TP; 1736 cmd->phy_address = 0; 1737 cmd->transceiver = XCVR_INTERNAL; 1738 cmd->autoneg = AUTONEG_DISABLE; 1739 cmd->maxtxpkt = 0; 1740 cmd->maxrxpkt = 0; 1741 return 0; 1742 } 1743 1744 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) 1745 { 1746 struct tun_struct *tun = netdev_priv(dev); 1747 1748 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 1749 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 1750 1751 switch (tun->flags & TUN_TYPE_MASK) { 1752 case TUN_TUN_DEV: 1753 strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); 1754 break; 1755 case TUN_TAP_DEV: 1756 strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); 1757 break; 1758 } 1759 } 1760 1761 static u32 tun_get_msglevel(struct net_device *dev) 1762 { 1763 #ifdef TUN_DEBUG 1764 struct tun_struct *tun = netdev_priv(dev); 1765 return tun->debug; 1766 #else 1767 return -EOPNOTSUPP; 1768 #endif 1769 } 1770 1771 static void tun_set_msglevel(struct net_device *dev, u32 value) 1772 { 1773 #ifdef TUN_DEBUG 1774 struct tun_struct *tun = netdev_priv(dev); 1775 tun->debug = value; 1776 #endif 1777 } 1778 1779 static const struct ethtool_ops tun_ethtool_ops = { 1780 .get_settings = tun_get_settings, 1781 .get_drvinfo = tun_get_drvinfo, 1782 .get_msglevel = tun_get_msglevel, 1783 .set_msglevel = tun_set_msglevel, 1784 .get_link = ethtool_op_get_link, 1785 }; 1786 1787 1788 static int __init tun_init(void) 1789 { 1790 int ret = 0; 1791 1792 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); 1793 pr_info("%s\n", DRV_COPYRIGHT); 1794 1795 ret = rtnl_link_register(&tun_link_ops); 1796 if (ret) { 1797 pr_err("Can't register link_ops\n"); 1798 goto err_linkops; 1799 } 1800 1801 ret = misc_register(&tun_miscdev); 1802 if (ret) { 1803 pr_err("Can't register misc device %d\n", TUN_MINOR); 1804 goto err_misc; 1805 } 1806 return 0; 1807 err_misc: 1808 rtnl_link_unregister(&tun_link_ops); 1809 err_linkops: 1810 return ret; 1811 } 1812 1813 static void tun_cleanup(void) 1814 { 1815 misc_deregister(&tun_miscdev); 1816 rtnl_link_unregister(&tun_link_ops); 1817 } 1818 1819 /* Get an underlying socket object from tun file. Returns error unless file is 1820 * attached to a device. The returned object works like a packet socket, it 1821 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 1822 * holding a reference to the file for as long as the socket is in use. */ 1823 struct socket *tun_get_socket(struct file *file) 1824 { 1825 struct tun_struct *tun; 1826 if (file->f_op != &tun_fops) 1827 return ERR_PTR(-EINVAL); 1828 tun = tun_get(file); 1829 if (!tun) 1830 return ERR_PTR(-EBADFD); 1831 tun_put(tun); 1832 return &tun->socket; 1833 } 1834 EXPORT_SYMBOL_GPL(tun_get_socket); 1835 1836 module_init(tun_init); 1837 module_exit(tun_cleanup); 1838 MODULE_DESCRIPTION(DRV_DESCRIPTION); 1839 MODULE_AUTHOR(DRV_COPYRIGHT); 1840 MODULE_LICENSE("GPL"); 1841 MODULE_ALIAS_MISCDEV(TUN_MINOR); 1842 MODULE_ALIAS("devname:net/tun"); 1843