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kernel-fxtec-pro1x/drivers/net/tun.c
Herbert Xu 33dccbb050 tun: Limit amount of queued packets per device 
Unlike a normal socket path, the tuntap device send path does
not have any accounting.  This means that the user-space sender
may be able to pin down arbitrary amounts of kernel memory by
continuing to send data to an end-point that is congested.

Even when this isn't an issue because of limited queueing at
most end points, this can also be a problem because its only
response to congestion is packet loss.  That is, when those
local queues at the end-point fills up, the tuntap device will
start wasting system time because it will continue to send
data there which simply gets dropped straight away.

Of course one could argue that everybody should do congestion
control end-to-end, unfortunately there are people in this world
still hooked on UDP, and they don't appear to be going away
anywhere fast.  In fact, we've always helped them by performing
accounting in our UDP code, the sole purpose of which is to
provide congestion feedback other than through packet loss.

This patch attempts to apply the same bandaid to the tuntap device.
It creates a pseudo-socket object which is used to account our
packets just as a normal socket does for UDP.  Of course things
are a little complex because we're actually reinjecting traffic
back into the stack rather than out of the stack.

The stack complexities however should have been resolved by preceding
patches.  So this one can simply start using skb_set_owner_w.

For now the accounting is essentially disabled by default for
backwards compatibility.  In particular, we set the cap to INT_MAX.
This is so that existing applications don't get confused by the
sudden arrival EAGAIN errors.

In future we may wish (or be forced to) do this by default.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-05 21:25:32 -08:00

1436 lines
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/*
* 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 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/smp_lock.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/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 <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 DBG if(tun->debug)printk
#define DBG1 if(debug==2)printk
#else
#define DBG( a... )
#define DBG1( a... )
#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;
wait_queue_head_t read_wait;
};
struct tun_sock;
struct tun_struct {
struct tun_file *tfile;
unsigned int flags;
uid_t owner;
gid_t group;
struct sk_buff_head readq;
struct net_device *dev;
struct fasync_struct *fasync;
struct tap_filter txflt;
struct sock *sk;
struct socket socket;
#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;
const struct cred *cred = current_cred();
int err;
ASSERT_RTNL();
/* Check permissions */
if (((tun->owner != -1 && cred->euid != tun->owner) ||
(tun->group != -1 && !in_egroup_p(tun->group))) &&
!capable(CAP_NET_ADMIN))
return -EPERM;
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;
dev_hold(tun->dev);
atomic_inc(&tfile->count);
out:
netif_tx_unlock_bh(tun->dev);
return err;
}
static void __tun_detach(struct tun_struct *tun)
{
struct tun_file *tfile = tun->tfile;
/* Detach from net device */
netif_tx_lock_bh(tun->dev);
tfile->tun = NULL;
tun->tfile = NULL;
netif_tx_unlock_bh(tun->dev);
/* Drop read queue */
skb_queue_purge(&tun->readq);
/* 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 filterting */
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;
/* The rest is hashed */
memset(filter->mask, 0, sizeof(filter->mask));
for (; n < uf.count; n++)
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(&tfile->read_wait);
if (atomic_dec_and_test(&tfile->count))
__tun_detach(tun);
}
}
/* 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 int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, 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 (skb_queue_len(&tun->readq) >= 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;
}
}
/* Enqueue packet */
skb_queue_tail(&tun->readq, skb);
dev->trans_start = jiffies;
/* Notify and wake up reader process */
if (tun->flags & TUN_FASYNC)
kill_fasync(&tun->fasync, SIGIO, POLL_IN);
wake_up_interruptible(&tun->tfile->read_wait);
return 0;
drop:
dev->stats.tx_dropped++;
kfree_skb(skb);
return 0;
}
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.
*/
return;
}
#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 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,
};
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_set_multicast_list = tun_net_mclist,
.ndo_set_mac_address = eth_mac_addr,
.ndo_validate_addr = eth_validate_addr,
};
/* 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);
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 = tun->sk;
unsigned int mask = 0;
if (!tun)
return POLLERR;
DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
poll_wait(file, &tfile->read_wait, wait);
if (!skb_queue_empty(&tun->readq))
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->sk;
struct sk_buff *skb;
int err;
/* Under a page? Don't bother with paged skb. */
if (prepad + len < PAGE_SIZE)
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,
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 };
if (!(tun->flags & TUN_NO_PI)) {
if ((len -= sizeof(pi)) > count)
return -EINVAL;
if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
return -EFAULT;
}
if (tun->flags & TUN_VNET_HDR) {
if ((len -= sizeof(gso)) > count)
return -EINVAL;
if (memcpy_fromiovec((void *)&gso, iv, sizeof(gso)))
return -EFAULT;
if (gso.hdr_len > len)
return -EINVAL;
}
if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
align = NET_IP_ALIGN;
if (unlikely(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, 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;
}
} else if (tun->flags & TUN_NOCHECKSUM)
skb->ip_summed = CHECKSUM_UNNECESSARY;
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;
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 = file->private_data;
ssize_t result;
if (!tun)
return -EBADFD;
DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
result = tun_get_user(tun, (struct iovec *)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,
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_toiovec(iv, (void *) &pi, sizeof(pi)))
return -EFAULT;
total += sizeof(pi);
}
if (tun->flags & TUN_VNET_HDR) {
struct virtio_net_hdr gso = { 0 }; /* no info leak */
if ((len -= sizeof(gso)) < 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
BUG();
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->csum_start - skb_headroom(skb);
gso.csum_offset = skb->csum_offset;
} /* else everything is zero */
if (unlikely(memcpy_toiovec(iv, (void *)&gso, sizeof(gso))))
return -EFAULT;
total += sizeof(gso);
}
len = min_t(int, skb->len, len);
skb_copy_datagram_iovec(skb, 0, iv, len);
total += len;
tun->dev->stats.tx_packets++;
tun->dev->stats.tx_bytes += len;
return total;
}
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);
DECLARE_WAITQUEUE(wait, current);
struct sk_buff *skb;
ssize_t len, ret = 0;
if (!tun)
return -EBADFD;
DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
len = iov_length(iv, count);
if (len < 0) {
ret = -EINVAL;
goto out;
}
add_wait_queue(&tfile->read_wait, &wait);
while (len) {
current->state = TASK_INTERRUPTIBLE;
/* Read frames from the queue */
if (!(skb=skb_dequeue(&tun->readq))) {
if (file->f_flags & O_NONBLOCK) {
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, (struct iovec *) iv, len);
kfree_skb(skb);
break;
}
current->state = TASK_RUNNING;
remove_wait_queue(&tfile->read_wait, &wait);
out:
tun_put(tun);
return ret;
}
static void tun_setup(struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
skb_queue_head_init(&tun->readq);
tun->owner = -1;
tun->group = -1;
dev->ethtool_ops = &tun_ethtool_ops;
dev->destructor = 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;
if (!sock_writeable(sk))
return;
if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
wake_up_interruptible_sync(sk->sk_sleep);
if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
return;
tun = container_of(sk, struct tun_sock, sk)->tun;
kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
}
static void tun_sock_destruct(struct sock *sk)
{
dev_put(container_of(sk, struct tun_sock, sk)->tun->dev);
}
static struct proto tun_proto = {
.name = "tun",
.owner = THIS_MODULE,
.obj_size = sizeof(struct tun_sock),
};
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;
struct tun_file *tfile = file->private_data;
int err;
dev = __dev_get_by_name(net, ifr->ifr_name);
if (dev) {
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;
err = tun_attach(tun, file);
if (err < 0)
return err;
}
else {
char *name;
unsigned long flags = 0;
err = -EINVAL;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
/* 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
goto failed;
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;
err = -ENOMEM;
sk = sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
if (!sk)
goto err_free_dev;
/* This ref count is for tun->sk. */
dev_hold(dev);
sock_init_data(&tun->socket, sk);
sk->sk_write_space = tun_sock_write_space;
sk->sk_destruct = tun_sock_destruct;
sk->sk_sndbuf = INT_MAX;
sk->sk_sleep = &tfile->read_wait;
tun->sk = sk;
container_of(sk, struct tun_sock, sk)->tun = tun;
tun_net_init(dev);
if (strchr(dev->name, '%')) {
err = dev_alloc_name(dev, dev->name);
if (err < 0)
goto err_free_sk;
}
err = -EINVAL;
err = register_netdevice(tun->dev);
if (err < 0)
goto err_free_dev;
err = tun_attach(tun, file);
if (err < 0)
goto err_free_dev;
}
DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
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 file *file, struct ifreq *ifr)
{
struct tun_struct *tun = tun_get(file);
if (!tun)
return -EBADFD;
DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
strcpy(ifr->ifr_name, tun->dev->name);
ifr->ifr_flags = 0;
if (ifr->ifr_flags & TUN_TUN_DEV)
ifr->ifr_flags |= IFF_TUN;
else
ifr->ifr_flags |= IFF_TAP;
if (tun->flags & TUN_NO_PI)
ifr->ifr_flags |= IFF_NO_PI;
if (tun->flags & TUN_ONE_QUEUE)
ifr->ifr_flags |= IFF_ONE_QUEUE;
if (tun->flags & TUN_VNET_HDR)
ifr->ifr_flags |= IFF_VNET_HDR;
tun_put(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 net_device *dev, unsigned long arg)
{
unsigned int old_features, features;
old_features = dev->features;
/* Unset features, set them as we chew on the arg. */
features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
|NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6));
if (arg & TUN_F_CSUM) {
features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
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);
}
}
/* This gives the user a way to test for new features in future by
* trying to set them. */
if (arg)
return -EINVAL;
dev->features = features;
if (old_features != dev->features)
netdev_features_change(dev);
return 0;
}
static int tun_chr_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct tun_file *tfile = file->private_data;
struct tun_struct *tun;
void __user* argp = (void __user*)arg;
struct ifreq ifr;
int sndbuf;
int ret;
if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
if (copy_from_user(&ifr, argp, sizeof ifr))
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);
}
tun = __tun_get(tfile);
if (cmd == TUNSETIFF && !tun) {
int err;
ifr.ifr_name[IFNAMSIZ-1] = '\0';
rtnl_lock();
err = tun_set_iff(tfile->net, file, &ifr);
rtnl_unlock();
if (err)
return err;
if (copy_to_user(argp, &ifr, sizeof(ifr)))
return -EFAULT;
return 0;
}
if (!tun)
return -EBADFD;
DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
ret = 0;
switch (cmd) {
case TUNGETIFF:
ret = tun_get_iff(current->nsproxy->net_ns, file, &ifr);
if (ret)
break;
if (copy_to_user(argp, &ifr, sizeof(ifr)))
ret = -EFAULT;
break;
case TUNSETNOCSUM:
/* Disable/Enable checksum */
if (arg)
tun->flags |= TUN_NOCHECKSUM;
else
tun->flags &= ~TUN_NOCHECKSUM;
DBG(KERN_INFO "%s: checksum %s\n",
tun->dev->name, arg ? "disabled" : "enabled");
break;
case TUNSETPERSIST:
/* Disable/Enable persist mode */
if (arg)
tun->flags |= TUN_PERSIST;
else
tun->flags &= ~TUN_PERSIST;
DBG(KERN_INFO "%s: persist %s\n",
tun->dev->name, arg ? "enabled" : "disabled");
break;
case TUNSETOWNER:
/* Set owner of the device */
tun->owner = (uid_t) arg;
DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
break;
case TUNSETGROUP:
/* Set group of the device */
tun->group= (gid_t) arg;
DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
break;
case TUNSETLINK:
/* Only allow setting the type when the interface is down */
rtnl_lock();
if (tun->dev->flags & IFF_UP) {
DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
tun->dev->name);
ret = -EBUSY;
} else {
tun->dev->type = (int) arg;
DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
ret = 0;
}
rtnl_unlock();
break;
#ifdef TUN_DEBUG
case TUNSETDEBUG:
tun->debug = arg;
break;
#endif
case TUNSETOFFLOAD:
rtnl_lock();
ret = set_offload(tun->dev, arg);
rtnl_unlock();
break;
case TUNSETTXFILTER:
/* Can be set only for TAPs */
ret = -EINVAL;
if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
break;
rtnl_lock();
ret = update_filter(&tun->txflt, (void __user *)arg);
rtnl_unlock();
break;
case SIOCGIFHWADDR:
/* Get hw addres */
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, sizeof ifr))
ret = -EFAULT;
break;
case SIOCSIFHWADDR:
/* Set hw address */
DBG(KERN_DEBUG "%s: set hw address: %pM\n",
tun->dev->name, ifr.ifr_hwaddr.sa_data);
rtnl_lock();
ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
rtnl_unlock();
break;
case TUNGETSNDBUF:
sndbuf = tun->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->sk->sk_sndbuf = sndbuf;
break;
default:
ret = -EINVAL;
break;
};
tun_put(tun);
return ret;
}
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;
DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
lock_kernel();
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:
unlock_kernel();
tun_put(tun);
return ret;
}
static int tun_chr_open(struct inode *inode, struct file * file)
{
struct tun_file *tfile;
cycle_kernel_lock();
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);
init_waitqueue_head(&tfile->read_wait);
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_get(tfile);
if (tun) {
DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
rtnl_lock();
__tun_detach(tun);
/* If desireable, unregister the netdevice. */
if (!(tun->flags & TUN_PERSIST)) {
sock_put(tun->sk);
unregister_netdevice(tun->dev);
}
rtnl_unlock();
}
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,
.ioctl = tun_chr_ioctl,
.open = tun_chr_open,
.release = tun_chr_close,
.fasync = tun_chr_fasync
};
static struct miscdevice tun_miscdev = {
.minor = TUN_MINOR,
.name = "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;
cmd->speed = 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 u32 tun_get_link(struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
return !!tun->tfile;
}
static u32 tun_get_rx_csum(struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
return (tun->flags & TUN_NOCHECKSUM) == 0;
}
static int tun_set_rx_csum(struct net_device *dev, u32 data)
{
struct tun_struct *tun = netdev_priv(dev);
if (data)
tun->flags &= ~TUN_NOCHECKSUM;
else
tun->flags |= TUN_NOCHECKSUM;
return 0;
}
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 = tun_get_link,
.get_rx_csum = tun_get_rx_csum,
.set_rx_csum = tun_set_rx_csum
};
static int __init tun_init(void)
{
int ret = 0;
printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
ret = rtnl_link_register(&tun_link_ops);
if (ret) {
printk(KERN_ERR "tun: Can't register link_ops\n");
goto err_linkops;
}
ret = misc_register(&tun_miscdev);
if (ret) {
printk(KERN_ERR "tun: 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);
}
module_init(tun_init);
module_exit(tun_cleanup);
MODULE_DESCRIPTION(DRV_DESCRIPTION);
MODULE_AUTHOR(DRV_COPYRIGHT);
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(TUN_MINOR);
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