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tuntap: add ioctl to attach or detach a file form tuntap device

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Sometimes usespace may need to active/deactive a queue, this could be done by
detaching and attaching a file from tuntap device.

This patch introduces a new ioctls - TUNSETQUEUE which could be used to do
this. Flag IFF_ATTACH_QUEUE were introduced to do attaching while
IFF_DETACH_QUEUE were introduced to do the detaching.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jason Wang 2012-10-31 19:46:01 +00:00 • committed by David S. Miller
parent c8d68e6be1
commit cde8b15f1a
2 changed files with 51 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

56
drivers/net/tun.c
View file

@ -195,6 +195,15 @@ static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb)
return txq; return txq;
} }
static inline bool tun_not_capable(struct tun_struct *tun)
{
const struct cred *cred = current_cred();
return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
(gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
!capable(CAP_NET_ADMIN);
}
static void tun_set_real_num_queues(struct tun_struct *tun) static void tun_set_real_num_queues(struct tun_struct *tun)
{ {
netif_set_real_num_tx_queues(tun->dev, tun->numqueues); netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
@ -1310,8 +1319,6 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
dev = __dev_get_by_name(net, ifr->ifr_name); dev = __dev_get_by_name(net, ifr->ifr_name);
if (dev) { if (dev) {
const struct cred *cred = current_cred();
if (ifr->ifr_flags & IFF_TUN_EXCL) if (ifr->ifr_flags & IFF_TUN_EXCL)
return -EBUSY; return -EBUSY;
if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
@ -1321,9 +1328,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
else else
return -EINVAL; return -EINVAL;
if (((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || if (tun_not_capable(tun))
(gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
!capable(CAP_NET_ADMIN))
return -EPERM; return -EPERM;
err = security_tun_dev_attach(tfile->socket.sk); err = security_tun_dev_attach(tfile->socket.sk);
if (err < 0) if (err < 0)
@ -1530,6 +1535,40 @@ static void tun_set_sndbuf(struct tun_struct *tun)
} }
} }
static int tun_set_queue(struct file *file, struct ifreq *ifr)
{
struct tun_file *tfile = file->private_data;
struct tun_struct *tun;
struct net_device *dev;
int ret = 0;
rtnl_lock();
if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
dev = __dev_get_by_name(tfile->net, ifr->ifr_name);
if (!dev) {
ret = -EINVAL;
goto unlock;
}
tun = netdev_priv(dev);
if (dev->netdev_ops != &tap_netdev_ops &&
dev->netdev_ops != &tun_netdev_ops)
ret = -EINVAL;
else if (tun_not_capable(tun))
ret = -EPERM;
else
ret = tun_attach(tun, file);
} else if (ifr->ifr_flags & IFF_DETACH_QUEUE)
__tun_detach(tfile, false);
else
ret = -EINVAL;
unlock:
rtnl_unlock();
return ret;
}
static long __tun_chr_ioctl(struct file *file, unsigned int cmd, static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
unsigned long arg, int ifreq_len) unsigned long arg, int ifreq_len)
{ {
@ -1543,7 +1582,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
int vnet_hdr_sz; int vnet_hdr_sz;
int ret; int ret;
if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) { if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
if (copy_from_user(&ifr, argp, ifreq_len)) if (copy_from_user(&ifr, argp, ifreq_len))
return -EFAULT; return -EFAULT;
} else { } else {
@ -1554,9 +1593,10 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
* This is needed because we never checked for invalid flags on * This is needed because we never checked for invalid flags on
* TUNSETIFF. */ * TUNSETIFF. */
return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
IFF_VNET_HDR, IFF_VNET_HDR | IFF_MULTI_QUEUE,
(unsigned int __user*)argp); (unsigned int __user*)argp);
} } else if (cmd == TUNSETQUEUE)
return tun_set_queue(file, &ifr);
ret = 0; ret = 0;
rtnl_lock(); rtnl_lock();

3
include/uapi/linux/if_tun.h
View file

@ -54,6 +54,7 @@
#define TUNDETACHFILTER _IOW('T', 214, struct sock_fprog) #define TUNDETACHFILTER _IOW('T', 214, struct sock_fprog)
#define TUNGETVNETHDRSZ _IOR('T', 215, int) #define TUNGETVNETHDRSZ _IOR('T', 215, int)
#define TUNSETVNETHDRSZ _IOW('T', 216, int) #define TUNSETVNETHDRSZ _IOW('T', 216, int)
#define TUNSETQUEUE _IOW('T', 217, int)
/* TUNSETIFF ifr flags */ /* TUNSETIFF ifr flags */
#define IFF_TUN 0x0001 #define IFF_TUN 0x0001
@ -63,6 +64,8 @@
#define IFF_VNET_HDR 0x4000 #define IFF_VNET_HDR 0x4000
#define IFF_TUN_EXCL 0x8000 #define IFF_TUN_EXCL 0x8000
#define IFF_MULTI_QUEUE 0x0100 #define IFF_MULTI_QUEUE 0x0100
#define IFF_ATTACH_QUEUE 0x0200
#define IFF_DETACH_QUEUE 0x0400
/* Features for GSO (TUNSETOFFLOAD). */ /* Features for GSO (TUNSETOFFLOAD). */
#define TUN_F_CSUM 0x01 /* You can hand me unchecksummed packets. */ #define TUN_F_CSUM 0x01 /* You can hand me unchecksummed packets. */