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authorMark McLoughlin <markmc@redhat.com>2008-08-15 15:09:56 -0700
committerDavid S. Miller <davem@davemloft.net>2008-08-15 19:52:19 -0700
commite3b99556975907530aeb9745e7b3945a0da48f17 (patch)
tree97f764e5c8587efcba64ad8d0edce9fee094e143
parent04a0551c87363f100b04d28d7a15a632b70e18e7 (diff)
tun: TUNGETIFF interface to query name and flags
Add a TUNGETIFF interface so that userspace can query a tun/tap descriptor for its name and flags. This is needed because it is common for one app to create a tap interface, exec another app and pass it the file descriptor for the interface. Without TUNGETIFF the spawned app has no way of detecting wheter the interface has e.g. IFF_VNET_HDR set. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Acked-by: Max Krasnyansky <maxk@qualcomm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/tun.c39
-rw-r--r--include/linux/if_tun.h1
2 files changed, 40 insertions, 0 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index e6bbc639c2d0..95931a5a9883 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -748,6 +748,36 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
return err;
}
+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;
+}
+
/* 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)
@@ -833,6 +863,15 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
switch (cmd) {
+ 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;
+
case TUNSETNOCSUM:
/* Disable/Enable checksum */
if (arg)
diff --git a/include/linux/if_tun.h b/include/linux/if_tun.h
index 4c6307ad9fdb..8529f57ba263 100644
--- a/include/linux/if_tun.h
+++ b/include/linux/if_tun.h
@@ -45,6 +45,7 @@
#define TUNGETFEATURES _IOR('T', 207, unsigned int)
#define TUNSETOFFLOAD _IOW('T', 208, unsigned int)
#define TUNSETTXFILTER _IOW('T', 209, unsigned int)
+#define TUNGETIFF _IOR('T', 210, unsigned int)
/* TUNSETIFF ifr flags */
#define IFF_TUN 0x0001

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