[PATCH net-next v2] net: tuntap: add ioctl() TUNGETQUEUEINDEX to fetch queue index

From: Randy Li
Date: Thu Aug 01 2024 - 09:49:58 EST


We need the queue index in qdisc mapping rule. There is no way to
fetch that.

Changelog:
v2:
Fixes the flow when the queue is disabled in the tap type device.
Put this ioctl() under the lock protection for the tun device.

Signed-off-by: Randy Li <ayaka@xxxxxxxxxxx>
---
drivers/net/tap.c | 10 ++++++++++
drivers/net/tun.c | 13 +++++++++++++
include/uapi/linux/if_tun.h | 1 +
3 files changed, 24 insertions(+)

diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index 77574f7a3bd4..bbd717cf78a5 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -1120,6 +1120,16 @@ static long tap_ioctl(struct file *file, unsigned int cmd,
rtnl_unlock();
return ret;

+ case TUNGETQUEUEINDEX:
+ rtnl_lock();
+ if (!q->enabled)
+ ret = -EINVAL;
+ else
+ ret = put_user(q->queue_index, up);
+
+ rtnl_unlock();
+ return ret;
+
case SIOCGIFHWADDR:
rtnl_lock();
tap = tap_get_tap_dev(q);
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 1d06c560c5e6..05fa9727721e 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -3151,6 +3151,19 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
tfile->ifindex = ifindex;
goto unlock;
}
+ if (cmd == TUNGETQUEUEINDEX) {
+ ret = -EINVAL;
+ if (tfile->detached)
+ goto unlock;
+
+ ret = -EFAULT;
+ if(put_user(tfile->queue_index, (unsigned int __user*)argp))
+ goto unlock;
+
+ ret = 0;
+ goto unlock;
+ }
+

ret = -EBADFD;
if (!tun)
diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h
index 287cdc81c939..2668ca3b06a5 100644
--- a/include/uapi/linux/if_tun.h
+++ b/include/uapi/linux/if_tun.h
@@ -61,6 +61,7 @@
#define TUNSETFILTEREBPF _IOR('T', 225, int)
#define TUNSETCARRIER _IOW('T', 226, int)
#define TUNGETDEVNETNS _IO('T', 227)
+#define TUNGETQUEUEINDEX _IOR('T', 228, unsigned int)

/* TUNSETIFF ifr flags */
#define IFF_TUN 0x0001
--
2.45.2