ip tuntap del

[Zenaan Harkness <zen@freedbms.net>]

Anyone know why ip tuntap del requires the "mode"?

# ifconfig tapz
tapz: error fetching interface information: Device not found
# ip tuntap add mode tap tapz
# ifconfig tapz
tapz      Link encap:Ethernet  HWaddr 06:b8:f7:41:bf:08
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:500
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

# ip tuntap del tapz
ioctl(TUNSETIFF): Invalid argument
# ifconfig tapz
tapz      Link encap:Ethernet  HWaddr 06:b8:f7:41:bf:08
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:500
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

# ip tuntap del mode tap tapz
# ifconfig tapz
tapz: error fetching interface information: Device not found

We see that when deleting a tap device, we still have to include the
mode. From a user perspective that ought to be superfluous. Perhaps it
is some kernel driver optimization thing, which has not bee papered
over by ip command. A minor point in the scheme of things I guess.

So could the Usage output be made a little more accurate (possibly
not, without duplicating it for each of add and del subcommands):

# ip tuntap help
Usage: ip tuntap { add | del } [ dev PHYS_DEV ]
          [ mode { tun | tap } ] [ user USER ] [ group GROUP ]
          [ one_queue ] [ pi ] [ vnet_hdr ]

Where: USER  := { STRING | NUMBER }
       GROUP := { STRING | NUMBER }

Also, how can I find out what one_queue, pi and vnet_hdr options could be?

I am wondering if this interface of command "ip" could be made more
discoverable for users like myself, and how to go about 'suggesting'
that in an appropriate way?

TIA
Zenaan