[net-next v5 6/7] tuntap: add ioctl to attach or detach a file form tuntap device

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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@xxxxxxxxxx>
 drivers/net/tun.c           |   56 ++++++++++++++++++++++++++++++++++++------
 include/uapi/linux/if_tun.h |    3 ++
 2 files changed, 51 insertions(+), 8 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 2762c55..79b6f9e 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -195,6 +195,15 @@ static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb)
 	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)
 	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);
 	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)
@@ -1321,9 +1328,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 			return -EINVAL;
-		if (((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
-		     (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
-		    !capable(CAP_NET_ADMIN))
+		if (tun_not_capable(tun))
 			return -EPERM;
 		err = security_tun_dev_attach(tfile->socket.sk);
 		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;
+	rtnl_unlock();
+	return ret;
 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
 			    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 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))
 			return -EFAULT;
 	} 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
 		 * TUNSETIFF. */
 		return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
 				(unsigned int __user*)argp);
-	}
+	} else if (cmd == TUNSETQUEUE)
+		return tun_set_queue(file, &ifr);
 	ret = 0;
diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h
index 8ef3a87..958497a 100644
--- a/include/uapi/linux/if_tun.h
+++ b/include/uapi/linux/if_tun.h
@@ -54,6 +54,7 @@
 #define TUNDETACHFILTER _IOW('T', 214, struct sock_fprog)
 #define TUNGETVNETHDRSZ _IOR('T', 215, int)
 #define TUNSETVNETHDRSZ _IOW('T', 216, int)
+#define TUNSETQUEUE  _IOW('T', 217, int)
 /* TUNSETIFF ifr flags */
 #define IFF_TUN		0x0001
@@ -63,6 +64,8 @@
 #define IFF_VNET_HDR	0x4000
 #define IFF_TUN_EXCL	0x8000
 #define IFF_MULTI_QUEUE 0x0100
+#define IFF_ATTACH_QUEUE 0x0200
+#define IFF_DETACH_QUEUE 0x0400
 /* Features for GSO (TUNSETOFFLOAD). */
 #define TUN_F_CSUM	0x01	/* You can hand me unchecksummed packets. */

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Other Archives]     [Linux Kernel Newbies]     [Linux Driver Development]     [Linux EFI]     [Linux Backports]     [Linux Kbuild]     [Fedora Kernel]     [Linux Kernel Testers]     [Linux SH]     [Linux Omap]     [Linux Tape]     [Linux Input]     [Linux LEDS]     [Linux Kernel Janitors]     [Linux Kernel Packagers]     [Linux Doc]     [Linux Man Pages]     [Linux API]     [Linux Memory Management]     [Linux Modules]     [Linux Standards]     [Kernel Announce]     [Netdev]     [Git]     [Linux PCI]     Linux CAN Development     [Linux I2C]     [Linux RDMA]     [Linux NUMA]     [Netfilter]     [Netfilter Devel]     [SELinux]     [Bugtraq]     [FIO]     [Linux Perf Users]     [Linux Serial]     [Linux PPP]     [Linux ISDN]     [Linux Next]     [Kernel Stable Commits]     [Linux Tip Commits]     [Kernel MM Commits]     [Linux Security Module]     [AutoFS]     [Filesystem Development]     [Ext3 Filesystem]     [Linux bcache]     [Ext4 Filesystem]     [Linux BTRFS]     [Linux CEPH Filesystem]     [Linux XFS]     [XFS]     [Linux NFS]     [Linux CIFS]     [Ecryptfs]     [Linux NILFS]     [Linux Cachefs]     [Reiser FS]     [Initramfs]     [Linux FB Devel]     [Linux OpenGL]     [DRI Devel]     [Fastboot]     [Linux RT Users]     [Linux RT Stable]     [eCos]     [Corosync]     [Linux Clusters]     [LVS Devel]     [Hot Plug]     [Linux Virtualization]     [KVM]     [KVM PPC]     [KVM ia64]     [Linux Containers]     [Linux Hexagon]     [Linux Cgroups]     [Util Linux]     [Wireless]     [Linux Bluetooth]     [Bluez Devel]     [Ethernet Bridging]     [Embedded Linux]     [Barebox]     [Linux MMC]     [Linux IIO]     [Sparse]     [Smatch]     [Linux Arch]     [x86 Platform Driver]     [Linux ACPI]     [Linux IBM ACPI]     [LM Sensors]     [CPU Freq]     [Linux Power Management]     [Linmodems]     [Linux DCCP]     [Linux SCTP]     [ALSA Devel]     [Linux USB]     [Linux PA RISC]     [Linux Samsung SOC]     [MIPS Linux]     [IBM S/390 Linux]     [ARM Linux]     [ARM Kernel]     [ARM MSM]     [Tegra Devel]     [Sparc Linux]     [Linux Security]     [Linux Sound]     [Linux Media]     [Video 4 Linux]     [Linux IRDA Users]     [Linux for the blind]     [Linux RAID]     [Linux ATA RAID]     [Device Mapper]     [Linux SCSI]     [SCSI Target Devel]     [Linux SCSI Target Infrastructure]     [Linux IDE]     [Linux SMP]     [Linux AXP]     [Linux Alpha]     [Linux M68K]     [Linux ia64]     [Linux 8086]     [Linux x86_64]     [Linux Config]     [Linux Apps]     [Linux MSDOS]     [Linux X.25]     [Linux Crypto]     [DM Crypt]     [Linux Trace Users]     [Linux Btrace]     [Linux Watchdog]     [Utrace Devel]     [Linux C Programming]     [Linux Assembly]     [Dash]     [DWARVES]     [Hail Devel]     [Linux Kernel Debugger]     [Linux gcc]     [Gcc Help]     [X.Org]     [Wine]

Add to Google Powered by Linux

[Older Kernel Discussion]     [Yosemite National Park Forum]     [Large Format Photos]     [Gimp]     [Yosemite Photos]     [Stuff]