tun.c 27.9 KB
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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:
 *
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 *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
 *    Add TUNSETLINK ioctl to set the link encapsulation
 *
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 *  Mark Smith <markzzzsmith@yahoo.com.au>
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 *    Use random_ether_addr() for tap MAC address.
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 *
 *  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>
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#include <linux/smp_lock.h>
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#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>
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#include <linux/nsproxy.h>
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#include <linux/virtio_net.h>
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#include <net/net_namespace.h>
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#include <net/netns/generic.h>
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#include <asm/system.h>
#include <asm/uaccess.h>

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/* Uncomment to enable debugging */
/* #define TUN_DEBUG 1 */

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#ifdef TUN_DEBUG
static int debug;
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#define DBG  if(tun->debug)printk
#define DBG1 if(debug==2)printk
#else
#define DBG( a... )
#define DBG1( a... )
#endif

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#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];
};

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struct tun_struct {
	struct list_head        list;
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	unsigned int 		flags;
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	int			attached;
	uid_t			owner;
	gid_t			group;

	wait_queue_head_t	read_wait;
	struct sk_buff_head	readq;

	struct net_device	*dev;
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	struct fasync_struct	*fasync;
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	struct tap_filter       txflt;
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#ifdef TUN_DEBUG
	int debug;
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#endif
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};
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/* 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);
}

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/* Network device part of the driver */

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static unsigned int tun_net_id;
struct tun_net {
	struct list_head dev_list;
};

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static const struct ethtool_ops tun_ethtool_ops;
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/* 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->attached)
		goto drop;

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	/* 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;

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	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. */
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			dev->stats.tx_fifo_errors++;
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		} else {
			/* Single queue mode.
			 * Driver handles dropping of all packets itself. */
			goto drop;
		}
	}

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	/* Enqueue packet */
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	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->read_wait);
	return 0;

drop:
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	dev->stats.tx_dropped++;
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	kfree_skb(skb);
	return 0;
}

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static void tun_net_mclist(struct net_device *dev)
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{
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	/*
	 * 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;
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}

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#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;
}

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/* Initialize net device. */
static void tun_net_init(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);
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	switch (tun->flags & TUN_TYPE_MASK) {
	case TUN_TUN_DEV:
		/* Point-to-Point TUN Device */
		dev->hard_header_len = 0;
		dev->addr_len = 0;
		dev->mtu = 1500;
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		dev->change_mtu = tun_net_change_mtu;
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		/* Zero header length */
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		dev->type = ARPHRD_NONE;
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		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:
		/* Ethernet TAP Device */
		ether_setup(dev);
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		dev->change_mtu         = tun_net_change_mtu;
		dev->set_multicast_list = tun_net_mclist;
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		random_ether_addr(dev->dev_addr);
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		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)
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{
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	struct tun_struct *tun = file->private_data;
	unsigned int mask = POLLOUT | POLLWRNORM;

	if (!tun)
		return -EBADFD;

	DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);

	poll_wait(file, &tun->read_wait, wait);
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	if (!skb_queue_empty(&tun->readq))
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		mask |= POLLIN | POLLRDNORM;

	return mask;
}

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/* 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(size_t prepad, size_t len, size_t linear,
				     gfp_t gfp)
{
	struct sk_buff *skb;
	unsigned int i;

	skb = alloc_skb(prepad + len, gfp|__GFP_NOWARN);
	if (skb) {
		skb_reserve(skb, prepad);
		skb_put(skb, len);
		return skb;
	}

	/* Under a page?  Don't bother with paged skb. */
	if (prepad + len < PAGE_SIZE)
		return NULL;

	/* Start with a normal skb, and add pages. */
	skb = alloc_skb(prepad + linear, gfp);
	if (!skb)
		return NULL;

	skb_reserve(skb, prepad);
	skb_put(skb, linear);

	len -= linear;

	for (i = 0; i < MAX_SKB_FRAGS; i++) {
		skb_frag_t *f = &skb_shinfo(skb)->frags[i];

		f->page = alloc_page(gfp|__GFP_ZERO);
		if (!f->page)
			break;

		f->page_offset = 0;
		f->size = PAGE_SIZE;

		skb->data_len += PAGE_SIZE;
		skb->len += PAGE_SIZE;
		skb->truesize += PAGE_SIZE;
		skb_shinfo(skb)->nr_frags++;

		if (len < PAGE_SIZE) {
			len = 0;
			break;
		}
		len -= PAGE_SIZE;
	}

	/* Too large, or alloc fail? */
	if (unlikely(len)) {
		kfree_skb(skb);
		skb = NULL;
	}

	return skb;
}

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/* Get packet from user space buffer */
static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
{
	struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
	struct sk_buff *skb;
	size_t len = count, align = 0;
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	struct virtio_net_hdr gso = { 0 };
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	if (!(tun->flags & TUN_NO_PI)) {
		if ((len -= sizeof(pi)) > count)
			return -EINVAL;

		if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
			return -EFAULT;
	}

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	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;
	}

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	if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
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		align = NET_IP_ALIGN;
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		if (unlikely(len < ETH_HLEN))
			return -EINVAL;
	}
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	if (!(skb = tun_alloc_skb(align, len, gso.hdr_len, GFP_KERNEL))) {
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		tun->dev->stats.rx_dropped++;
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		return -ENOMEM;
	}

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	if (skb_copy_datagram_from_iovec(skb, 0, iv, len)) {
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		tun->dev->stats.rx_dropped++;
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		kfree_skb(skb);
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		return -EFAULT;
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	}
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	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;

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	switch (tun->flags & TUN_TYPE_MASK) {
	case TUN_TUN_DEV:
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		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;
			}
		}

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		skb_reset_mac_header(skb);
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		skb->protocol = pi.proto;
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		skb->dev = tun->dev;
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		break;
	case TUN_TAP_DEV:
		skb->protocol = eth_type_trans(skb, tun->dev);
		break;
	};

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	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;
	}
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	netif_rx_ni(skb);
	tun->dev->last_rx = jiffies;
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	tun->dev->stats.rx_packets++;
	tun->dev->stats.rx_bytes += len;
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	return count;
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}
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static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
			      unsigned long count, loff_t pos)
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{
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	struct tun_struct *tun = iocb->ki_filp->private_data;
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	if (!tun)
		return -EBADFD;

	DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);

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	return tun_get_user(tun, (struct iovec *) iv, iov_length(iv, count));
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}

/* 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;
		}
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		if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
			return -EFAULT;
		total += sizeof(pi);
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	}
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	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);
	}

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	len = min_t(int, skb->len, len);

	skb_copy_datagram_iovec(skb, 0, iv, len);
	total += len;

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	tun->dev->stats.tx_packets++;
	tun->dev->stats.tx_bytes += len;
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	return total;
}

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static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
			    unsigned long count, loff_t pos)
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{
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	struct file *file = iocb->ki_filp;
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	struct tun_struct *tun = file->private_data;
	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);

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	len = iov_length(iv, count);
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	if (len < 0)
		return -EINVAL;

	add_wait_queue(&tun->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;
			}

			/* Nothing to read, let's sleep */
			schedule();
			continue;
		}
		netif_wake_queue(tun->dev);

658 659 660
		ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
		kfree_skb(skb);
		break;
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	}

	current->state = TASK_RUNNING;
	remove_wait_queue(&tun->read_wait, &wait);

	return ret;
}

static void tun_setup(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);

	skb_queue_head_init(&tun->readq);
	init_waitqueue_head(&tun->read_wait);

	tun->owner = -1;
677
	tun->group = -1;
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	dev->open = tun_net_open;
	dev->hard_start_xmit = tun_net_xmit;
	dev->stop = tun_net_close;
	dev->ethtool_ops = &tun_ethtool_ops;
	dev->destructor = free_netdev;
684
	dev->features |= NETIF_F_NETNS_LOCAL;
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}

687
static struct tun_struct *tun_get_by_name(struct tun_net *tn, const char *name)
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{
	struct tun_struct *tun;

	ASSERT_RTNL();
692
	list_for_each_entry(tun, &tn->dev_list, list) {
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		if (!strncmp(tun->dev->name, name, IFNAMSIZ))
		    return tun;
	}

	return NULL;
}

700
static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
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{
702
	struct tun_net *tn;
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	struct tun_struct *tun;
	struct net_device *dev;
	int err;

707 708
	tn = net_generic(net, tun_net_id);
	tun = tun_get_by_name(tn, ifr->ifr_name);
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	if (tun) {
		if (tun->attached)
			return -EBUSY;

		/* Check permissions */
714 715 716 717 718
		if (((tun->owner != -1 &&
		      current->euid != tun->owner) ||
		     (tun->group != -1 &&
		      current->egid != tun->group)) &&
		     !capable(CAP_NET_ADMIN))
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			return -EPERM;
720
	}
721
	else if (__dev_get_by_name(net, ifr->ifr_name))
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		return -EINVAL;
	else {
		char *name;
		unsigned long flags = 0;

		err = -EINVAL;

729 730 731
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;

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		/* 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";
741
		} else
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			goto failed;
743

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		if (*ifr->ifr_name)
			name = ifr->ifr_name;

		dev = alloc_netdev(sizeof(struct tun_struct), name,
				   tun_setup);
		if (!dev)
			return -ENOMEM;

752
		dev_net_set(dev, net);
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		tun = netdev_priv(dev);
		tun->dev = dev;
		tun->flags = flags;
756
		tun->txflt.count = 0;
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		tun_net_init(dev);

		if (strchr(dev->name, '%')) {
			err = dev_alloc_name(dev, dev->name);
			if (err < 0)
				goto err_free_dev;
		}

		err = register_netdevice(tun->dev);
		if (err < 0)
			goto err_free_dev;
769

770
		list_add(&tun->list, &tn->dev_list);
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	}

	DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);

	if (ifr->ifr_flags & IFF_NO_PI)
		tun->flags |= TUN_NO_PI;
777 778
	else
		tun->flags &= ~TUN_NO_PI;
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	if (ifr->ifr_flags & IFF_ONE_QUEUE)
		tun->flags |= TUN_ONE_QUEUE;
782 783
	else
		tun->flags &= ~TUN_ONE_QUEUE;
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785 786 787 788 789
	if (ifr->ifr_flags & IFF_VNET_HDR)
		tun->flags |= TUN_VNET_HDR;
	else
		tun->flags &= ~TUN_VNET_HDR;

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	file->private_data = tun;
	tun->attached = 1;
792
	get_net(dev_net(tun->dev));
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794 795 796 797 798 799
	/* Make sure persistent devices do not get stuck in
	 * xoff state.
	 */
	if (netif_running(tun->dev))
		netif_wake_queue(tun->dev);

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	strcpy(ifr->ifr_name, tun->dev->name);
	return 0;

 err_free_dev:
	free_netdev(dev);
 failed:
	return err;
}

809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838
static int tun_get_iff(struct net *net, struct file *file, struct ifreq *ifr)
{
	struct tun_struct *tun = file->private_data;

	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;

	return 0;
}

839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878
/* 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;
}

879
static int tun_chr_ioctl(struct inode *inode, struct file *file,
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			 unsigned int cmd, unsigned long arg)
{
	struct tun_struct *tun = file->private_data;
	void __user* argp = (void __user*)arg;
	struct ifreq ifr;
885
	int ret;
886
	DECLARE_MAC_BUF(mac);
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	if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
		if (copy_from_user(&ifr, argp, sizeof ifr))
			return -EFAULT;

	if (cmd == TUNSETIFF && !tun) {
		int err;

		ifr.ifr_name[IFNAMSIZ-1] = '\0';

		rtnl_lock();
898
		err = tun_set_iff(current->nsproxy->net_ns, file, &ifr);
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		rtnl_unlock();

		if (err)
			return err;

		if (copy_to_user(argp, &ifr, sizeof(ifr)))
			return -EFAULT;
		return 0;
	}

909 910 911 912
	if (cmd == TUNGETFEATURES) {
		/* Currently this just means: "what IFF flags are valid?".
		 * This is needed because we never checked for invalid flags on
		 * TUNSETIFF. */
913 914
		return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
				IFF_VNET_HDR,
915 916 917
				(unsigned int __user*)argp);
	}

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	if (!tun)
		return -EBADFD;

	DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);

	switch (cmd) {
924 925 926 927 928 929 930 931 932
	case TUNGETIFF:
		ret = tun_get_iff(current->nsproxy->net_ns, file, &ifr);
		if (ret)
			return ret;

		if (copy_to_user(argp, &ifr, sizeof(ifr)))
			return -EFAULT;
		break;

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	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",
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		    tun->dev->name, arg ? "enabled" : "disabled");
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		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;

962 963 964 965 966 967 968
	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;

969 970
	case TUNSETLINK:
		/* Only allow setting the type when the interface is down */
971
		rtnl_lock();
972 973 974
		if (tun->dev->flags & IFF_UP) {
			DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
				tun->dev->name);
975
			ret = -EBUSY;
976 977 978
		} else {
			tun->dev->type = (int) arg;
			DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
979
			ret = 0;
980
		}
981 982
		rtnl_unlock();
		return ret;
983

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#ifdef TUN_DEBUG
	case TUNSETDEBUG:
		tun->debug = arg;
		break;
#endif
989 990 991 992 993 994
	case TUNSETOFFLOAD:
		rtnl_lock();
		ret = set_offload(tun->dev, arg);
		rtnl_unlock();
		return ret;

995 996 997 998 999
	case TUNSETTXFILTER:
		/* Can be set only for TAPs */
		if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
			return -EINVAL;
		rtnl_lock();
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		ret = update_filter(&tun->txflt, (void __user *)arg);
1001 1002
		rtnl_unlock();
		return ret;
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	case SIOCGIFHWADDR:
1005 1006 1007 1008
		/* 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))
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			return -EFAULT;
		return 0;

	case SIOCSIFHWADDR:
1013 1014 1015
		/* Set hw address */
		DBG(KERN_DEBUG "%s: set hw address: %s\n",
			tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
1016 1017 1018 1019

		rtnl_lock();
		ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
		rtnl_unlock();
1020
		return ret;
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	default:
		return -EINVAL;
	};

	return 0;
}

static int tun_chr_fasync(int fd, struct file *file, int on)
{
	struct tun_struct *tun = file->private_data;
	int ret;

	if (!tun)
		return -EBADFD;

	DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);

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	lock_kernel();
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	if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
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		goto out;
1042

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	if (on) {
1044
		ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
L
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		if (ret)
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			goto out;
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		tun->flags |= TUN_FASYNC;
1048
	} else
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		tun->flags &= ~TUN_FASYNC;
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	ret = 0;
out:
	unlock_kernel();
	return ret;
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}

static int tun_chr_open(struct inode *inode, struct file * file)
{
A
Arnd Bergmann 已提交
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	cycle_kernel_lock();
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	DBG1(KERN_INFO "tunX: tun_chr_open\n");
	file->private_data = NULL;
	return 0;
}

static int tun_chr_close(struct inode *inode, struct file *file)
{
	struct tun_struct *tun = file->private_data;

	if (!tun)
		return 0;

	DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);

	tun_chr_fasync(-1, file, 0);

	rtnl_lock();

	/* Detach from net device */
	file->private_data = NULL;
	tun->attached = 0;
1080
	put_net(dev_net(tun->dev));
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	/* Drop read queue */
	skb_queue_purge(&tun->readq);

	if (!(tun->flags & TUN_PERSIST)) {
		list_del(&tun->list);
		unregister_netdevice(tun->dev);
	}

	rtnl_unlock();

	return 0;
}

1095
static const struct file_operations tun_fops = {
1096
	.owner	= THIS_MODULE,
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	.llseek = no_llseek,
1098 1099 1100 1101
	.read  = do_sync_read,
	.aio_read  = tun_chr_aio_read,
	.write = do_sync_write,
	.aio_write = tun_chr_aio_write,
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	.poll	= tun_chr_poll,
	.ioctl	= tun_chr_ioctl,
	.open	= tun_chr_open,
	.release = tun_chr_close,
1106
	.fasync = tun_chr_fasync
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1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189
};

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->attached;
}

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;
}

1190
static const struct ethtool_ops tun_ethtool_ops = {
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	.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
};

1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220
static int tun_init_net(struct net *net)
{
	struct tun_net *tn;

	tn = kmalloc(sizeof(*tn), GFP_KERNEL);
	if (tn == NULL)
		return -ENOMEM;

	INIT_LIST_HEAD(&tn->dev_list);

	if (net_assign_generic(net, tun_net_id, tn)) {
		kfree(tn);
		return -ENOMEM;
	}

	return 0;
}

static void tun_exit_net(struct net *net)
{
	struct tun_net *tn;
1221
	struct tun_struct *tun, *nxt;
1222 1223

	tn = net_generic(net, tun_net_id);
1224 1225 1226 1227 1228 1229 1230 1231

	rtnl_lock();
	list_for_each_entry_safe(tun, nxt, &tn->dev_list, list) {
		DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
		unregister_netdevice(tun->dev);
	}
	rtnl_unlock();

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	kfree(tn);
}

static struct pernet_operations tun_net_ops = {
	.init = tun_init_net,
	.exit = tun_exit_net,
};

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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);

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	ret = register_pernet_gen_device(&tun_net_id, &tun_net_ops);
	if (ret) {
		printk(KERN_ERR "tun: Can't register pernet ops\n");
		goto err_pernet;
	}

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	ret = misc_register(&tun_miscdev);
1254
	if (ret) {
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		printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
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		goto err_misc;
	}
	return 0;

err_misc:
	unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
err_pernet:
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	return ret;
}

static void tun_cleanup(void)
{
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	misc_deregister(&tun_miscdev);
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	unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
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}

module_init(tun_init);
module_exit(tun_cleanup);
MODULE_DESCRIPTION(DRV_DESCRIPTION);
MODULE_AUTHOR(DRV_COPYRIGHT);
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(TUN_MINOR);