diff options
Diffstat (limited to 'drivers/net/tun.c')
| -rw-r--r-- | drivers/net/tun.c | 1689 |
1 files changed, 1689 insertions, 0 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c new file mode 100644 index 00000000..76b86506 --- /dev/null +++ b/drivers/net/tun.c @@ -0,0 +1,1689 @@ +/* + * TUN - Universal TUN/TAP device driver. + * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com> + * + * 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 <dragorn@kismetwireless.net> 2005/08/14 + * Add TUNSETLINK ioctl to set the link encapsulation + * + * Mark Smith <markzzzsmith@yahoo.com.au> + * Use random_ether_addr() for tap MAC address. + * + * Harald Roelle <harald.roelle@ifi.lmu.de> 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 <underley@underley.eu.org> + * 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 <maxk@qualcomm.com>" + +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/major.h> +#include <linux/slab.h> +#include <linux/poll.h> +#include <linux/fcntl.h> +#include <linux/init.h> +#include <linux/skbuff.h> +#include <linux/netdevice.h> +#include <linux/etherdevice.h> +#include <linux/miscdevice.h> +#include <linux/ethtool.h> +#include <linux/rtnetlink.h> +#include <linux/compat.h> +#include <linux/if.h> +#include <linux/if_arp.h> +#include <linux/if_ether.h> +#include <linux/if_tun.h> +#include <linux/crc32.h> +#include <linux/nsproxy.h> +#include <linux/virtio_net.h> +#include <linux/rcupdate.h> +#include <net/net_namespace.h> +#include <net/netns/generic.h> +#include <net/rtnetlink.h> +#include <net/sock.h> + +#include <asm/system.h> +#include <asm/uaccess.h> + +/* 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 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; + uid_t owner; + gid_t group; + + struct net_device *dev; + u32 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; + tun->socket.file = 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 (!compare_ether_addr(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); + + sock_put(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. */ + 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 u32 tun_net_fix_features(struct net_device *dev, u32 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_multicast_list = 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; + + random_ether_addr(dev->dev_addr); + + 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 inline 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); + + /* 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; +} + +/* Get packet from user space buffer */ +static __inline__ ssize_t tun_get_user(struct tun_struct *tun, + const struct iovec *iv, size_t count, + int noblock) +{ + struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; + struct sk_buff *skb; + size_t len = count, align = 0; + struct virtio_net_hdr gso = { 0 }; + int offset = 0; + + if (!(tun->flags & TUN_NO_PI)) { + if ((len -= sizeof(pi)) > count) + 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) > count) + 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; + } + + skb = tun_alloc_skb(tun, align, len, gso.hdr_len, noblock); + if (IS_ERR(skb)) { + if (PTR_ERR(skb) != -EAGAIN) + tun->dev->stats.rx_dropped++; + return PTR_ERR(skb); + } + + if (skb_copy_datagram_from_iovec(skb, 0, iv, offset, len)) { + 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; + } + + netif_rx_ni(skb); + + tun->dev->stats.rx_packets++; + tun->dev->stats.rx_bytes += len; + + return count; +} + +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, iv, iov_length(iv, count), + file->f_flags & O_NONBLOCK); + + tun_put(tun); + return result; +} + +/* Put packet to the user space buffer */ +static __inline__ 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 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"); + + 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; + 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 = -1; + tun->group = -1; + + 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_iov, total_len, + 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; +} + +/* Ops structure to mimic raw sockets with tun */ +static const struct proto_ops tun_socket_ops = { + .sendmsg = tun_sendmsg, + .recvmsg = tun_recvmsg, +}; + +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 sprintf(buf, "%d\n", tun->owner); +} + +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 sprintf(buf, "%d\n", tun->group); +} + +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 (((tun->owner != -1 && cred->euid != tun->owner) || + (tun->group != -1 && !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); + + err = -ENOMEM; + sk = sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &tun_proto); + if (!sk) + goto err_free_dev; + + 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; + + 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: + sock_put(sk); + 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) +{ + u32 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; + int sndbuf; + int vnet_hdr_sz; + int ret; + +#ifdef CONFIG_ANDROID_PARANOID_NETWORK + if (cmd != TUNGETIFF && !capable(CAP_NET_ADMIN)) { + return -EPERM; + } +#endif + + if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) + if (copy_from_user(&ifr, argp, ifreq_len)) + return -EFAULT; + + 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 */ + tun->owner = (uid_t) arg; + + tun_debug(KERN_INFO, tun, "owner set to %d\n", tun->owner); + break; + + case TUNSETGROUP: + /* Set group of the device */ + tun->group= (gid_t) arg; + + tun_debug(KERN_INFO, tun, "group set to %d\n", 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); + + strcpy(info->driver, DRV_NAME); + strcpy(info->version, DRV_VERSION); + strcpy(info->fw_version, "N/A"); + + switch (tun->flags & TUN_TYPE_MASK) { + case TUN_TUN_DEV: + strcpy(info->bus_info, "tun"); + break; + case TUN_TAP_DEV: + strcpy(info->bus_info, "tap"); + 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"); |