/* * TUN - Universal TUN/TAP device driver. * Copyright (C) 1999-2002 Maxim Krasnyansky * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $ */ /* * Changes: * * Mike Kershaw 2005/08/14 * Add TUNSETLINK ioctl to set the link encapsulation * * Mark Smith * Use eth_random_addr() for tap MAC address. * * Harald Roelle 2004/04/20 * Fixes in packet dropping, queue length setting and queue wakeup. * Increased default tx queue length. * Added ethtool API. * Minor cleanups * * Daniel Podlejski * Modifications for 2.3.99-pre5 kernel. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #define DRV_NAME "tun" #define DRV_VERSION "1.6" #define DRV_DESCRIPTION "Universal TUN/TAP device driver" #define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky " #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* Uncomment to enable debugging */ /* #define TUN_DEBUG 1 */ #ifdef TUN_DEBUG static int debug; #define tun_debug(level, tun, fmt, args...) \ do { \ if (tun->debug) \ netdev_printk(level, tun->dev, fmt, ##args); \ } while (0) #define DBG1(level, fmt, args...) \ do { \ if (debug == 2) \ printk(level fmt, ##args); \ } while (0) #else #define tun_debug(level, tun, fmt, args...) \ do { \ if (0) \ netdev_printk(level, tun->dev, fmt, ##args); \ } while (0) #define DBG1(level, fmt, args...) \ do { \ if (0) \ printk(level fmt, ##args); \ } while (0) #endif #define GOODCOPY_LEN 128 #define FLT_EXACT_COUNT 8 struct tap_filter { unsigned int count; /* Number of addrs. Zero means disabled */ u32 mask[2]; /* Mask of the hashed addrs */ unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; }; struct tun_file { atomic_t count; struct tun_struct *tun; struct net *net; }; struct tun_sock; struct tun_struct { struct tun_file *tfile; unsigned int flags; kuid_t owner; kgid_t group; struct net_device *dev; netdev_features_t set_features; #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ NETIF_F_TSO6|NETIF_F_UFO) struct fasync_struct *fasync; struct tap_filter txflt; struct socket socket; struct socket_wq wq; int vnet_hdr_sz; #ifdef TUN_DEBUG int debug; #endif }; struct tun_sock { struct sock sk; struct tun_struct *tun; }; static inline struct tun_sock *tun_sk(struct sock *sk) { return container_of(sk, struct tun_sock, sk); } static int tun_attach(struct tun_struct *tun, struct file *file) { struct tun_file *tfile = file->private_data; int err; ASSERT_RTNL(); netif_tx_lock_bh(tun->dev); err = -EINVAL; if (tfile->tun) goto out; err = -EBUSY; if (tun->tfile) goto out; err = 0; tfile->tun = tun; tun->tfile = tfile; tun->socket.file = file; netif_carrier_on(tun->dev); dev_hold(tun->dev); sock_hold(tun->socket.sk); atomic_inc(&tfile->count); out: netif_tx_unlock_bh(tun->dev); return err; } static void __tun_detach(struct tun_struct *tun) { /* Detach from net device */ netif_tx_lock_bh(tun->dev); netif_carrier_off(tun->dev); tun->tfile = NULL; netif_tx_unlock_bh(tun->dev); /* Drop read queue */ skb_queue_purge(&tun->socket.sk->sk_receive_queue); /* Drop the extra count on the net device */ dev_put(tun->dev); } static void tun_detach(struct tun_struct *tun) { rtnl_lock(); __tun_detach(tun); rtnl_unlock(); } static struct tun_struct *__tun_get(struct tun_file *tfile) { struct tun_struct *tun = NULL; if (atomic_inc_not_zero(&tfile->count)) tun = tfile->tun; return tun; } static struct tun_struct *tun_get(struct file *file) { return __tun_get(file->private_data); } static void tun_put(struct tun_struct *tun) { struct tun_file *tfile = tun->tfile; if (atomic_dec_and_test(&tfile->count)) tun_detach(tfile->tun); } /* TAP filtering */ static void addr_hash_set(u32 *mask, const u8 *addr) { int n = ether_crc(ETH_ALEN, addr) >> 26; mask[n >> 5] |= (1 << (n & 31)); } static unsigned int addr_hash_test(const u32 *mask, const u8 *addr) { int n = ether_crc(ETH_ALEN, addr) >> 26; return mask[n >> 5] & (1 << (n & 31)); } static int update_filter(struct tap_filter *filter, void __user *arg) { struct { u8 u[ETH_ALEN]; } *addr; struct tun_filter uf; int err, alen, n, nexact; if (copy_from_user(&uf, arg, sizeof(uf))) return -EFAULT; if (!uf.count) { /* Disabled */ filter->count = 0; return 0; } alen = ETH_ALEN * uf.count; addr = kmalloc(alen, GFP_KERNEL); if (!addr) return -ENOMEM; if (copy_from_user(addr, arg + sizeof(uf), alen)) { err = -EFAULT; goto done; } /* The filter is updated without holding any locks. Which is * perfectly safe. We disable it first and in the worst * case we'll accept a few undesired packets. */ filter->count = 0; wmb(); /* Use first set of addresses as an exact filter */ for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++) memcpy(filter->addr[n], addr[n].u, ETH_ALEN); nexact = n; /* Remaining multicast addresses are hashed, * unicast will leave the filter disabled. */ memset(filter->mask, 0, sizeof(filter->mask)); for (; n < uf.count; n++) { if (!is_multicast_ether_addr(addr[n].u)) { err = 0; /* no filter */ goto done; } addr_hash_set(filter->mask, addr[n].u); } /* For ALLMULTI just set the mask to all ones. * This overrides the mask populated above. */ if ((uf.flags & TUN_FLT_ALLMULTI)) memset(filter->mask, ~0, sizeof(filter->mask)); /* Now enable the filter */ wmb(); filter->count = nexact; /* Return the number of exact filters */ err = nexact; done: kfree(addr); return err; } /* Returns: 0 - drop, !=0 - accept */ static int run_filter(struct tap_filter *filter, const struct sk_buff *skb) { /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect * at this point. */ struct ethhdr *eh = (struct ethhdr *) skb->data; int i; /* Exact match */ for (i = 0; i < filter->count; i++) if (ether_addr_equal(eh->h_dest, filter->addr[i])) return 1; /* Inexact match (multicast only) */ if (is_multicast_ether_addr(eh->h_dest)) return addr_hash_test(filter->mask, eh->h_dest); return 0; } /* * Checks whether the packet is accepted or not. * Returns: 0 - drop, !=0 - accept */ static int check_filter(struct tap_filter *filter, const struct sk_buff *skb) { if (!filter->count) return 1; return run_filter(filter, skb); } /* Network device part of the driver */ static const struct ethtool_ops tun_ethtool_ops; /* Net device detach from fd. */ static void tun_net_uninit(struct net_device *dev) { struct tun_struct *tun = netdev_priv(dev); struct tun_file *tfile = tun->tfile; /* Inform the methods they need to stop using the dev. */ if (tfile) { wake_up_all(&tun->wq.wait); if (atomic_dec_and_test(&tfile->count)) __tun_detach(tun); } } static void tun_free_netdev(struct net_device *dev) { struct tun_struct *tun = netdev_priv(dev); BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags)); sk_release_kernel(tun->socket.sk); } /* Net device open. */ static int tun_net_open(struct net_device *dev) { netif_start_queue(dev); return 0; } /* Net device close. */ static int tun_net_close(struct net_device *dev) { netif_stop_queue(dev); return 0; } /* Net device start xmit */ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) { struct tun_struct *tun = netdev_priv(dev); tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); /* Drop packet if interface is not attached */ if (!tun->tfile) goto drop; /* Drop if the filter does not like it. * This is a noop if the filter is disabled. * Filter can be enabled only for the TAP devices. */ if (!check_filter(&tun->txflt, skb)) goto drop; if (tun->socket.sk->sk_filter && sk_filter(tun->socket.sk, skb)) goto drop; if (skb_queue_len(&tun->socket.sk->sk_receive_queue) >= dev->tx_queue_len) { if (!(tun->flags & TUN_ONE_QUEUE)) { /* Normal queueing mode. */ /* Packet scheduler handles dropping of further packets. */ netif_stop_queue(dev); /* We won't see all dropped packets individually, so overrun * error is more appropriate. */ dev->stats.tx_fifo_errors++; } else { /* Single queue mode. * Driver handles dropping of all packets itself. */ goto drop; } } /* Orphan the skb - required as we might hang on to it * for indefinite time. */ if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) goto drop; skb_orphan(skb); /* Enqueue packet */ skb_queue_tail(&tun->socket.sk->sk_receive_queue, skb); /* Notify and wake up reader process */ if (tun->flags & TUN_FASYNC) kill_fasync(&tun->fasync, SIGIO, POLL_IN); wake_up_interruptible_poll(&tun->wq.wait, POLLIN | POLLRDNORM | POLLRDBAND); return NETDEV_TX_OK; drop: dev->stats.tx_dropped++; kfree_skb(skb); return NETDEV_TX_OK; } static void tun_net_mclist(struct net_device *dev) { /* * This callback is supposed to deal with mc filter in * _rx_ path and has nothing to do with the _tx_ path. * In rx path we always accept everything userspace gives us. */ } #define MIN_MTU 68 #define MAX_MTU 65535 static int tun_net_change_mtu(struct net_device *dev, int new_mtu) { if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) return -EINVAL; dev->mtu = new_mtu; return 0; } static netdev_features_t tun_net_fix_features(struct net_device *dev, netdev_features_t features) { struct tun_struct *tun = netdev_priv(dev); return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); } #ifdef CONFIG_NET_POLL_CONTROLLER static void tun_poll_controller(struct net_device *dev) { /* * Tun only receives frames when: * 1) the char device endpoint gets data from user space * 2) the tun socket gets a sendmsg call from user space * Since both of those are syncronous operations, we are guaranteed * never to have pending data when we poll for it * so theres nothing to do here but return. * We need this though so netpoll recognizes us as an interface that * supports polling, which enables bridge devices in virt setups to * still use netconsole */ return; } #endif static const struct net_device_ops tun_netdev_ops = { .ndo_uninit = tun_net_uninit, .ndo_open = tun_net_open, .ndo_stop = tun_net_close, .ndo_start_xmit = tun_net_xmit, .ndo_change_mtu = tun_net_change_mtu, .ndo_fix_features = tun_net_fix_features, #ifdef CONFIG_NET_POLL_CONTROLLER .ndo_poll_controller = tun_poll_controller, #endif }; static const struct net_device_ops tap_netdev_ops = { .ndo_uninit = tun_net_uninit, .ndo_open = tun_net_open, .ndo_stop = tun_net_close, .ndo_start_xmit = tun_net_xmit, .ndo_change_mtu = tun_net_change_mtu, .ndo_fix_features = tun_net_fix_features, .ndo_set_rx_mode = tun_net_mclist, .ndo_set_mac_address = eth_mac_addr, .ndo_validate_addr = eth_validate_addr, #ifdef CONFIG_NET_POLL_CONTROLLER .ndo_poll_controller = tun_poll_controller, #endif }; /* Initialize net device. */ static void tun_net_init(struct net_device *dev) { struct tun_struct *tun = netdev_priv(dev); switch (tun->flags & TUN_TYPE_MASK) { case TUN_TUN_DEV: dev->netdev_ops = &tun_netdev_ops; /* Point-to-Point TUN Device */ dev->hard_header_len = 0; dev->addr_len = 0; dev->mtu = 1500; /* Zero header length */ dev->type = ARPHRD_NONE; dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ break; case TUN_TAP_DEV: dev->netdev_ops = &tap_netdev_ops; /* Ethernet TAP Device */ ether_setup(dev); dev->priv_flags &= ~IFF_TX_SKB_SHARING; eth_hw_addr_random(dev); dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ break; } } /* Character device part */ /* Poll */ static unsigned int tun_chr_poll(struct file *file, poll_table * wait) { struct tun_file *tfile = file->private_data; struct tun_struct *tun = __tun_get(tfile); struct sock *sk; unsigned int mask = 0; if (!tun) return POLLERR; sk = tun->socket.sk; tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); poll_wait(file, &tun->wq.wait, wait); if (!skb_queue_empty(&sk->sk_receive_queue)) mask |= POLLIN | POLLRDNORM; if (sock_writeable(sk) || (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && sock_writeable(sk))) mask |= POLLOUT | POLLWRNORM; if (tun->dev->reg_state != NETREG_REGISTERED) mask = POLLERR; tun_put(tun); return mask; } /* prepad is the amount to reserve at front. len is length after that. * linear is a hint as to how much to copy (usually headers). */ static struct sk_buff *tun_alloc_skb(struct tun_struct *tun, size_t prepad, size_t len, size_t linear, int noblock) { struct sock *sk = tun->socket.sk; struct sk_buff *skb; int err; sock_update_classid(sk, current); /* Under a page? Don't bother with paged skb. */ if (prepad + len < PAGE_SIZE || !linear) linear = len; skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, &err); if (!skb) return ERR_PTR(err); skb_reserve(skb, prepad); skb_put(skb, linear); skb->data_len = len - linear; skb->len += len - linear; return skb; } /* set skb frags from iovec, this can move to core network code for reuse */ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, int offset, size_t count) { int len = iov_length(from, count) - offset; int copy = skb_headlen(skb); int size, offset1 = 0; int i = 0; /* Skip over from offset */ while (count && (offset >= from->iov_len)) { offset -= from->iov_len; ++from; --count; } /* copy up to skb headlen */ while (count && (copy > 0)) { size = min_t(unsigned int, copy, from->iov_len - offset); if (copy_from_user(skb->data + offset1, from->iov_base + offset, size)) return -EFAULT; if (copy > size) { ++from; --count; offset = 0; } else offset += size; copy -= size; offset1 += size; } if (len == offset1) return 0; while (count--) { struct page *page[MAX_SKB_FRAGS]; int num_pages; unsigned long base; unsigned long truesize; len = from->iov_len - offset; if (!len) { offset = 0; ++from; continue; } base = (unsigned long)from->iov_base + offset; size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; if (i + size > MAX_SKB_FRAGS) return -EMSGSIZE; num_pages = get_user_pages_fast(base, size, 0, &page[i]); if (num_pages != size) { for (i = 0; i < num_pages; i++) put_page(page[i]); return -EFAULT; } truesize = size * PAGE_SIZE; skb->data_len += len; skb->len += len; skb->truesize += truesize; atomic_add(truesize, &skb->sk->sk_wmem_alloc); while (len) { int off = base & ~PAGE_MASK; int size = min_t(int, len, PAGE_SIZE - off); __skb_fill_page_desc(skb, i, page[i], off, size); skb_shinfo(skb)->nr_frags++; /* increase sk_wmem_alloc */ base += size; len -= size; i++; } offset = 0; ++from; } return 0; } /* Get packet from user space buffer */ static ssize_t tun_get_user(struct tun_struct *tun, void *msg_control, const struct iovec *iv, size_t total_len, size_t count, int noblock) { struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; struct sk_buff *skb; size_t len = total_len, align = NET_SKB_PAD; struct virtio_net_hdr gso = { 0 }; int offset = 0; int copylen; bool zerocopy = false; int err; if (!(tun->flags & TUN_NO_PI)) { if ((len -= sizeof(pi)) > total_len) return -EINVAL; if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) return -EFAULT; offset += sizeof(pi); } if (tun->flags & TUN_VNET_HDR) { if ((len -= tun->vnet_hdr_sz) > total_len) return -EINVAL; if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) return -EFAULT; if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) gso.hdr_len = gso.csum_start + gso.csum_offset + 2; if (gso.hdr_len > len) return -EINVAL; offset += tun->vnet_hdr_sz; } if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { align += NET_IP_ALIGN; if (unlikely(len < ETH_HLEN || (gso.hdr_len && gso.hdr_len < ETH_HLEN))) return -EINVAL; } if (msg_control) zerocopy = true; if (zerocopy) { /* Userspace may produce vectors with count greater than * MAX_SKB_FRAGS, so we need to linearize parts of the skb * to let the rest of data to be fit in the frags. */ if (count > MAX_SKB_FRAGS) { copylen = iov_length(iv, count - MAX_SKB_FRAGS); if (copylen < offset) copylen = 0; else copylen -= offset; } else copylen = 0; /* There are 256 bytes to be copied in skb, so there is enough * room for skb expand head in case it is used. * The rest of the buffer is mapped from userspace. */ if (copylen < gso.hdr_len) copylen = gso.hdr_len; if (!copylen) copylen = GOODCOPY_LEN; } else copylen = len; skb = tun_alloc_skb(tun, align, copylen, gso.hdr_len, noblock); if (IS_ERR(skb)) { if (PTR_ERR(skb) != -EAGAIN) tun->dev->stats.rx_dropped++; return PTR_ERR(skb); } if (zerocopy) err = zerocopy_sg_from_iovec(skb, iv, offset, count); else err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len); if (err) { tun->dev->stats.rx_dropped++; kfree_skb(skb); return -EFAULT; } if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { if (!skb_partial_csum_set(skb, gso.csum_start, gso.csum_offset)) { tun->dev->stats.rx_frame_errors++; kfree_skb(skb); return -EINVAL; } } switch (tun->flags & TUN_TYPE_MASK) { case TUN_TUN_DEV: if (tun->flags & TUN_NO_PI) { switch (skb->data[0] & 0xf0) { case 0x40: pi.proto = htons(ETH_P_IP); break; case 0x60: pi.proto = htons(ETH_P_IPV6); break; default: tun->dev->stats.rx_dropped++; kfree_skb(skb); return -EINVAL; } } skb_reset_mac_header(skb); skb->protocol = pi.proto; skb->dev = tun->dev; break; case TUN_TAP_DEV: skb->protocol = eth_type_trans(skb, tun->dev); break; } if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { pr_debug("GSO!\n"); switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { case VIRTIO_NET_HDR_GSO_TCPV4: skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; break; case VIRTIO_NET_HDR_GSO_TCPV6: skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; break; case VIRTIO_NET_HDR_GSO_UDP: skb_shinfo(skb)->gso_type = SKB_GSO_UDP; break; default: tun->dev->stats.rx_frame_errors++; kfree_skb(skb); return -EINVAL; } if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; skb_shinfo(skb)->gso_size = gso.gso_size; if (skb_shinfo(skb)->gso_size == 0) { tun->dev->stats.rx_frame_errors++; kfree_skb(skb); return -EINVAL; } /* Header must be checked, and gso_segs computed. */ skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; skb_shinfo(skb)->gso_segs = 0; } /* copy skb_ubuf_info for callback when skb has no error */ if (zerocopy) { skb_shinfo(skb)->destructor_arg = msg_control; skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; } netif_rx_ni(skb); tun->dev->stats.rx_packets++; tun->dev->stats.rx_bytes += len; return total_len; } static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, unsigned long count, loff_t pos) { struct file *file = iocb->ki_filp; struct tun_struct *tun = tun_get(file); ssize_t result; if (!tun) return -EBADFD; tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count); result = tun_get_user(tun, NULL, iv, iov_length(iv, count), count, file->f_flags & O_NONBLOCK); tun_put(tun); return result; } /* Put packet to the user space buffer */ static ssize_t tun_put_user(struct tun_struct *tun, struct sk_buff *skb, const struct iovec *iv, int len) { struct tun_pi pi = { 0, skb->protocol }; ssize_t total = 0; if (!(tun->flags & TUN_NO_PI)) { if ((len -= sizeof(pi)) < 0) return -EINVAL; if (len < skb->len) { /* Packet will be striped */ pi.flags |= TUN_PKT_STRIP; } if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi))) return -EFAULT; total += sizeof(pi); } if (tun->flags & TUN_VNET_HDR) { struct virtio_net_hdr gso = { 0 }; /* no info leak */ if ((len -= tun->vnet_hdr_sz) < 0) return -EINVAL; if (skb_is_gso(skb)) { struct skb_shared_info *sinfo = skb_shinfo(skb); /* This is a hint as to how much should be linear. */ gso.hdr_len = skb_headlen(skb); gso.gso_size = sinfo->gso_size; if (sinfo->gso_type & SKB_GSO_TCPV4) gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; else if (sinfo->gso_type & SKB_GSO_TCPV6) gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; else if (sinfo->gso_type & SKB_GSO_UDP) gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; else { pr_err("unexpected GSO type: " "0x%x, gso_size %d, hdr_len %d\n", sinfo->gso_type, gso.gso_size, gso.hdr_len); print_hex_dump(KERN_ERR, "tun: ", DUMP_PREFIX_NONE, 16, 1, skb->head, min((int)gso.hdr_len, 64), true); WARN_ON_ONCE(1); return -EINVAL; } if (sinfo->gso_type & SKB_GSO_TCP_ECN) gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; } else gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; if (skb->ip_summed == CHECKSUM_PARTIAL) { gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; gso.csum_start = skb_checksum_start_offset(skb); gso.csum_offset = skb->csum_offset; } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; } /* else everything is zero */ if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, sizeof(gso)))) return -EFAULT; total += tun->vnet_hdr_sz; } len = min_t(int, skb->len, len); skb_copy_datagram_const_iovec(skb, 0, iv, total, len); total += skb->len; tun->dev->stats.tx_packets++; tun->dev->stats.tx_bytes += len; return total; } static ssize_t tun_do_read(struct tun_struct *tun, struct kiocb *iocb, const struct iovec *iv, ssize_t len, int noblock) { DECLARE_WAITQUEUE(wait, current); struct sk_buff *skb; ssize_t ret = 0; tun_debug(KERN_INFO, tun, "tun_chr_read\n"); if (unlikely(!noblock)) add_wait_queue(&tun->wq.wait, &wait); while (len) { current->state = TASK_INTERRUPTIBLE; /* Read frames from the queue */ if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) { if (noblock) { ret = -EAGAIN; break; } if (signal_pending(current)) { ret = -ERESTARTSYS; break; } if (tun->dev->reg_state != NETREG_REGISTERED) { ret = -EIO; break; } /* Nothing to read, let's sleep */ schedule(); continue; } netif_wake_queue(tun->dev); ret = tun_put_user(tun, skb, iv, len); kfree_skb(skb); break; } current->state = TASK_RUNNING; if (unlikely(!noblock)) remove_wait_queue(&tun->wq.wait, &wait); return ret; } static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, unsigned long count, loff_t pos) { struct file *file = iocb->ki_filp; struct tun_file *tfile = file->private_data; struct tun_struct *tun = __tun_get(tfile); ssize_t len, ret; if (!tun) return -EBADFD; len = iov_length(iv, count); if (len < 0) { ret = -EINVAL; goto out; } ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK); ret = min_t(ssize_t, ret, len); out: tun_put(tun); return ret; } static void tun_setup(struct net_device *dev) { struct tun_struct *tun = netdev_priv(dev); tun->owner = INVALID_UID; tun->group = INVALID_GID; dev->ethtool_ops = &tun_ethtool_ops; dev->destructor = tun_free_netdev; } /* Trivial set of netlink ops to allow deleting tun or tap * device with netlink. */ static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) { return -EINVAL; } static struct rtnl_link_ops tun_link_ops __read_mostly = { .kind = DRV_NAME, .priv_size = sizeof(struct tun_struct), .setup = tun_setup, .validate = tun_validate, }; static void tun_sock_write_space(struct sock *sk) { struct tun_struct *tun; wait_queue_head_t *wqueue; if (!sock_writeable(sk)) return; if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) return; wqueue = sk_sleep(sk); if (wqueue && waitqueue_active(wqueue)) wake_up_interruptible_sync_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND); tun = tun_sk(sk)->tun; kill_fasync(&tun->fasync, SIGIO, POLL_OUT); } static void tun_sock_destruct(struct sock *sk) { free_netdev(tun_sk(sk)->tun->dev); } static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m, size_t total_len) { struct tun_struct *tun = container_of(sock, struct tun_struct, socket); return tun_get_user(tun, m->msg_control, m->msg_iov, total_len, m->msg_iovlen, m->msg_flags & MSG_DONTWAIT); } static int tun_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m, size_t total_len, int flags) { struct tun_struct *tun = container_of(sock, struct tun_struct, socket); int ret; if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) return -EINVAL; ret = tun_do_read(tun, iocb, m->msg_iov, total_len, flags & MSG_DONTWAIT); if (ret > total_len) { m->msg_flags |= MSG_TRUNC; ret = flags & MSG_TRUNC ? ret : total_len; } return ret; } static int tun_release(struct socket *sock) { if (sock->sk) sock_put(sock->sk); return 0; } /* Ops structure to mimic raw sockets with tun */ static const struct proto_ops tun_socket_ops = { .sendmsg = tun_sendmsg, .recvmsg = tun_recvmsg, .release = tun_release, }; static struct proto tun_proto = { .name = "tun", .owner = THIS_MODULE, .obj_size = sizeof(struct tun_sock), }; static int tun_flags(struct tun_struct *tun) { int flags = 0; if (tun->flags & TUN_TUN_DEV) flags |= IFF_TUN; else flags |= IFF_TAP; if (tun->flags & TUN_NO_PI) flags |= IFF_NO_PI; if (tun->flags & TUN_ONE_QUEUE) flags |= IFF_ONE_QUEUE; if (tun->flags & TUN_VNET_HDR) flags |= IFF_VNET_HDR; return flags; } static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, char *buf) { struct tun_struct *tun = netdev_priv(to_net_dev(dev)); return sprintf(buf, "0x%x\n", tun_flags(tun)); } static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, char *buf) { struct tun_struct *tun = netdev_priv(to_net_dev(dev)); return uid_valid(tun->owner)? sprintf(buf, "%u\n", from_kuid_munged(current_user_ns(), tun->owner)): sprintf(buf, "-1\n"); } static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, char *buf) { struct tun_struct *tun = netdev_priv(to_net_dev(dev)); return gid_valid(tun->group) ? sprintf(buf, "%u\n", from_kgid_munged(current_user_ns(), tun->group)): sprintf(buf, "-1\n"); } static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); static DEVICE_ATTR(group, 0444, tun_show_group, NULL); static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) { struct sock *sk; struct tun_struct *tun; struct net_device *dev; int err; dev = __dev_get_by_name(net, ifr->ifr_name); if (dev) { const struct cred *cred = current_cred(); if (ifr->ifr_flags & IFF_TUN_EXCL) return -EBUSY; if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) tun = netdev_priv(dev); else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops) tun = netdev_priv(dev); else return -EINVAL; if (((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || (gid_valid(tun->group) && !in_egroup_p(tun->group))) && !capable(CAP_NET_ADMIN)) return -EPERM; err = security_tun_dev_attach(tun->socket.sk); if (err < 0) return err; err = tun_attach(tun, file); if (err < 0) return err; } else { char *name; unsigned long flags = 0; if (!capable(CAP_NET_ADMIN)) return -EPERM; err = security_tun_dev_create(); if (err < 0) return err; /* Set dev type */ if (ifr->ifr_flags & IFF_TUN) { /* TUN device */ flags |= TUN_TUN_DEV; name = "tun%d"; } else if (ifr->ifr_flags & IFF_TAP) { /* TAP device */ flags |= TUN_TAP_DEV; name = "tap%d"; } else return -EINVAL; if (*ifr->ifr_name) name = ifr->ifr_name; dev = alloc_netdev(sizeof(struct tun_struct), name, tun_setup); if (!dev) return -ENOMEM; dev_net_set(dev, net); dev->rtnl_link_ops = &tun_link_ops; tun = netdev_priv(dev); tun->dev = dev; tun->flags = flags; tun->txflt.count = 0; tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); set_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags); err = -ENOMEM; sk = sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, &tun_proto); if (!sk) goto err_free_dev; sk_change_net(sk, net); tun->socket.wq = &tun->wq; init_waitqueue_head(&tun->wq.wait); tun->socket.ops = &tun_socket_ops; sock_init_data(&tun->socket, sk); sk->sk_write_space = tun_sock_write_space; sk->sk_sndbuf = INT_MAX; sock_set_flag(sk, SOCK_ZEROCOPY); tun_sk(sk)->tun = tun; security_tun_dev_post_create(sk); tun_net_init(dev); dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | TUN_USER_FEATURES; dev->features = dev->hw_features; err = register_netdevice(tun->dev); if (err < 0) goto err_free_sk; if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || device_create_file(&tun->dev->dev, &dev_attr_owner) || device_create_file(&tun->dev->dev, &dev_attr_group)) pr_err("Failed to create tun sysfs files\n"); sk->sk_destruct = tun_sock_destruct; err = tun_attach(tun, file); if (err < 0) goto failed; } tun_debug(KERN_INFO, tun, "tun_set_iff\n"); if (ifr->ifr_flags & IFF_NO_PI) tun->flags |= TUN_NO_PI; else tun->flags &= ~TUN_NO_PI; if (ifr->ifr_flags & IFF_ONE_QUEUE) tun->flags |= TUN_ONE_QUEUE; else tun->flags &= ~TUN_ONE_QUEUE; if (ifr->ifr_flags & IFF_VNET_HDR) tun->flags |= TUN_VNET_HDR; else tun->flags &= ~TUN_VNET_HDR; /* Make sure persistent devices do not get stuck in * xoff state. */ if (netif_running(tun->dev)) netif_wake_queue(tun->dev); strcpy(ifr->ifr_name, tun->dev->name); return 0; err_free_sk: tun_free_netdev(dev); err_free_dev: free_netdev(dev); failed: return err; } static int tun_get_iff(struct net *net, struct tun_struct *tun, struct ifreq *ifr) { tun_debug(KERN_INFO, tun, "tun_get_iff\n"); strcpy(ifr->ifr_name, tun->dev->name); ifr->ifr_flags = tun_flags(tun); return 0; } /* This is like a cut-down ethtool ops, except done via tun fd so no * privs required. */ static int set_offload(struct tun_struct *tun, unsigned long arg) { netdev_features_t features = 0; if (arg & TUN_F_CSUM) { features |= NETIF_F_HW_CSUM; arg &= ~TUN_F_CSUM; if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { if (arg & TUN_F_TSO_ECN) { features |= NETIF_F_TSO_ECN; arg &= ~TUN_F_TSO_ECN; } if (arg & TUN_F_TSO4) features |= NETIF_F_TSO; if (arg & TUN_F_TSO6) features |= NETIF_F_TSO6; arg &= ~(TUN_F_TSO4|TUN_F_TSO6); } if (arg & TUN_F_UFO) { features |= NETIF_F_UFO; arg &= ~TUN_F_UFO; } } /* This gives the user a way to test for new features in future by * trying to set them. */ if (arg) return -EINVAL; tun->set_features = features; netdev_update_features(tun->dev); return 0; } static long __tun_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg, int ifreq_len) { struct tun_file *tfile = file->private_data; struct tun_struct *tun; void __user* argp = (void __user*)arg; struct sock_fprog fprog; struct ifreq ifr; kuid_t owner; kgid_t group; int sndbuf; int vnet_hdr_sz; int ret; if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) { if (copy_from_user(&ifr, argp, ifreq_len)) return -EFAULT; } else { memset(&ifr, 0, sizeof(ifr)); } if (cmd == TUNGETFEATURES) { /* Currently this just means: "what IFF flags are valid?". * This is needed because we never checked for invalid flags on * TUNSETIFF. */ return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR, (unsigned int __user*)argp); } rtnl_lock(); tun = __tun_get(tfile); if (cmd == TUNSETIFF && !tun) { ifr.ifr_name[IFNAMSIZ-1] = '\0'; ret = tun_set_iff(tfile->net, file, &ifr); if (ret) goto unlock; if (copy_to_user(argp, &ifr, ifreq_len)) ret = -EFAULT; goto unlock; } ret = -EBADFD; if (!tun) goto unlock; tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %d\n", cmd); ret = 0; switch (cmd) { case TUNGETIFF: ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr); if (ret) break; if (copy_to_user(argp, &ifr, ifreq_len)) ret = -EFAULT; break; case TUNSETNOCSUM: /* Disable/Enable checksum */ /* [unimplemented] */ tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", arg ? "disabled" : "enabled"); break; case TUNSETPERSIST: /* Disable/Enable persist mode */ if (arg) tun->flags |= TUN_PERSIST; else tun->flags &= ~TUN_PERSIST; tun_debug(KERN_INFO, tun, "persist %s\n", arg ? "enabled" : "disabled"); break; case TUNSETOWNER: /* Set owner of the device */ owner = make_kuid(current_user_ns(), arg); if (!uid_valid(owner)) { ret = -EINVAL; break; } tun->owner = owner; tun_debug(KERN_INFO, tun, "owner set to %d\n", from_kuid(&init_user_ns, tun->owner)); break; case TUNSETGROUP: /* Set group of the device */ group = make_kgid(current_user_ns(), arg); if (!gid_valid(group)) { ret = -EINVAL; break; } tun->group = group; tun_debug(KERN_INFO, tun, "group set to %d\n", from_kgid(&init_user_ns, tun->group)); break; case TUNSETLINK: /* Only allow setting the type when the interface is down */ if (tun->dev->flags & IFF_UP) { tun_debug(KERN_INFO, tun, "Linktype set failed because interface is up\n"); ret = -EBUSY; } else { tun->dev->type = (int) arg; tun_debug(KERN_INFO, tun, "linktype set to %d\n", tun->dev->type); ret = 0; } break; #ifdef TUN_DEBUG case TUNSETDEBUG: tun->debug = arg; break; #endif case TUNSETOFFLOAD: ret = set_offload(tun, arg); break; case TUNSETTXFILTER: /* Can be set only for TAPs */ ret = -EINVAL; if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) break; ret = update_filter(&tun->txflt, (void __user *)arg); break; case SIOCGIFHWADDR: /* Get hw address */ memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); ifr.ifr_hwaddr.sa_family = tun->dev->type; if (copy_to_user(argp, &ifr, ifreq_len)) ret = -EFAULT; break; case SIOCSIFHWADDR: /* Set hw address */ tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", ifr.ifr_hwaddr.sa_data); ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); break; case TUNGETSNDBUF: sndbuf = tun->socket.sk->sk_sndbuf; if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) ret = -EFAULT; break; case TUNSETSNDBUF: if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { ret = -EFAULT; break; } tun->socket.sk->sk_sndbuf = sndbuf; break; case TUNGETVNETHDRSZ: vnet_hdr_sz = tun->vnet_hdr_sz; if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz))) ret = -EFAULT; break; case TUNSETVNETHDRSZ: if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) { ret = -EFAULT; break; } if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) { ret = -EINVAL; break; } tun->vnet_hdr_sz = vnet_hdr_sz; break; case TUNATTACHFILTER: /* Can be set only for TAPs */ ret = -EINVAL; if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) break; ret = -EFAULT; if (copy_from_user(&fprog, argp, sizeof(fprog))) break; ret = sk_attach_filter(&fprog, tun->socket.sk); break; case TUNDETACHFILTER: /* Can be set only for TAPs */ ret = -EINVAL; if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) break; ret = sk_detach_filter(tun->socket.sk); break; default: ret = -EINVAL; break; } unlock: rtnl_unlock(); if (tun) tun_put(tun); return ret; } static long tun_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); } #ifdef CONFIG_COMPAT static long tun_chr_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { switch (cmd) { case TUNSETIFF: case TUNGETIFF: case TUNSETTXFILTER: case TUNGETSNDBUF: case TUNSETSNDBUF: case SIOCGIFHWADDR: case SIOCSIFHWADDR: arg = (unsigned long)compat_ptr(arg); break; default: arg = (compat_ulong_t)arg; break; } /* * compat_ifreq is shorter than ifreq, so we must not access beyond * the end of that structure. All fields that are used in this * driver are compatible though, we don't need to convert the * contents. */ return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); } #endif /* CONFIG_COMPAT */ static int tun_chr_fasync(int fd, struct file *file, int on) { struct tun_struct *tun = tun_get(file); int ret; if (!tun) return -EBADFD; tun_debug(KERN_INFO, tun, "tun_chr_fasync %d\n", on); if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0) goto out; if (on) { ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0); if (ret) goto out; tun->flags |= TUN_FASYNC; } else tun->flags &= ~TUN_FASYNC; ret = 0; out: tun_put(tun); return ret; } static int tun_chr_open(struct inode *inode, struct file * file) { struct tun_file *tfile; DBG1(KERN_INFO, "tunX: tun_chr_open\n"); tfile = kmalloc(sizeof(*tfile), GFP_KERNEL); if (!tfile) return -ENOMEM; atomic_set(&tfile->count, 0); tfile->tun = NULL; tfile->net = get_net(current->nsproxy->net_ns); file->private_data = tfile; return 0; } static int tun_chr_close(struct inode *inode, struct file *file) { struct tun_file *tfile = file->private_data; struct tun_struct *tun; tun = __tun_get(tfile); if (tun) { struct net_device *dev = tun->dev; tun_debug(KERN_INFO, tun, "tun_chr_close\n"); __tun_detach(tun); /* If desirable, unregister the netdevice. */ if (!(tun->flags & TUN_PERSIST)) { rtnl_lock(); if (dev->reg_state == NETREG_REGISTERED) unregister_netdevice(dev); rtnl_unlock(); } } tun = tfile->tun; if (tun) sock_put(tun->socket.sk); put_net(tfile->net); kfree(tfile); return 0; } static const struct file_operations tun_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .read = do_sync_read, .aio_read = tun_chr_aio_read, .write = do_sync_write, .aio_write = tun_chr_aio_write, .poll = tun_chr_poll, .unlocked_ioctl = tun_chr_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = tun_chr_compat_ioctl, #endif .open = tun_chr_open, .release = tun_chr_close, .fasync = tun_chr_fasync }; static struct miscdevice tun_miscdev = { .minor = TUN_MINOR, .name = "tun", .nodename = "net/tun", .fops = &tun_fops, }; /* ethtool interface */ static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) { cmd->supported = 0; cmd->advertising = 0; ethtool_cmd_speed_set(cmd, SPEED_10); cmd->duplex = DUPLEX_FULL; cmd->port = PORT_TP; cmd->phy_address = 0; cmd->transceiver = XCVR_INTERNAL; cmd->autoneg = AUTONEG_DISABLE; cmd->maxtxpkt = 0; cmd->maxrxpkt = 0; return 0; } static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) { struct tun_struct *tun = netdev_priv(dev); strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); strlcpy(info->version, DRV_VERSION, sizeof(info->version)); switch (tun->flags & TUN_TYPE_MASK) { case TUN_TUN_DEV: strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); break; case TUN_TAP_DEV: strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); break; } } static u32 tun_get_msglevel(struct net_device *dev) { #ifdef TUN_DEBUG struct tun_struct *tun = netdev_priv(dev); return tun->debug; #else return -EOPNOTSUPP; #endif } static void tun_set_msglevel(struct net_device *dev, u32 value) { #ifdef TUN_DEBUG struct tun_struct *tun = netdev_priv(dev); tun->debug = value; #endif } static const struct ethtool_ops tun_ethtool_ops = { .get_settings = tun_get_settings, .get_drvinfo = tun_get_drvinfo, .get_msglevel = tun_get_msglevel, .set_msglevel = tun_set_msglevel, .get_link = ethtool_op_get_link, }; static int __init tun_init(void) { int ret = 0; pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); pr_info("%s\n", DRV_COPYRIGHT); ret = rtnl_link_register(&tun_link_ops); if (ret) { pr_err("Can't register link_ops\n"); goto err_linkops; } ret = misc_register(&tun_miscdev); if (ret) { pr_err("Can't register misc device %d\n", TUN_MINOR); goto err_misc; } return 0; err_misc: rtnl_link_unregister(&tun_link_ops); err_linkops: return ret; } static void tun_cleanup(void) { misc_deregister(&tun_miscdev); rtnl_link_unregister(&tun_link_ops); } /* Get an underlying socket object from tun file. Returns error unless file is * attached to a device. The returned object works like a packet socket, it * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for * holding a reference to the file for as long as the socket is in use. */ struct socket *tun_get_socket(struct file *file) { struct tun_struct *tun; if (file->f_op != &tun_fops) return ERR_PTR(-EINVAL); tun = tun_get(file); if (!tun) return ERR_PTR(-EBADFD); tun_put(tun); return &tun->socket; } EXPORT_SYMBOL_GPL(tun_get_socket); module_init(tun_init); module_exit(tun_cleanup); MODULE_DESCRIPTION(DRV_DESCRIPTION); MODULE_AUTHOR(DRV_COPYRIGHT); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(TUN_MINOR); MODULE_ALIAS("devname:net/tun");