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