RFC: L2TPv3 interface

[Kengo NAKAHARA <k-nakahara%iij.ad.jp@localhost>]

Hi,

My co-workers implemented L2TPv3(RFC3931) interface for old version NetBSD.
And then, I port the inteface to NetBSD-current and MP-ify. Here is the patch.
    http://netbsd.org/~knakahara/if-l2tp/if-l2tp.patch

The L2TPv3 interface implementation is named l2tp(4), which can send/receive
L2TPv3 data packet and control packet. Above patch include ifconfig(8)
extension, so we can create L2TPv3 tunnel between hostA and hostB as below.
========== host A ==========
# ifconfig wm0 inet 192.168.0.1/24
# ifconfig l2tp0 create
# ifconfig l2tp0 tunnel 192.168.0.1 192.168.0.2
# ifconfig l2tp0 session 1234 4321
# ifconfig bridge0 create
# brconfig bridge0 add wm1
# brconfig bridge0 add l2tp0
# ifconfig l2tp0 up
# ifconfig wm1 up
# ifconfig bridge0 up
========== host A ==========

========== host B ==========
# ifconfig l2tp0 create
# ifconfig l2tp0 tunnel 192.168.0.2 192.168.0.1
# ifconfig l2tp0 session 4321 1234
# ifconfig bridge0 create
# brconfig bridge0 add wm1
# brconfig bridge0 add l2tp0
# ifconfig l2tp0 up
# ifconfig wm1 up
# ifconfig bridge0 up
========== host B ==========

As l2tp(4) interface can send/receive L2TPv3 control packet, we can implement
userland daemon which manage sessions, that is, authentication, keepalive, and
so on. That's future work.

Could you comment this patch?


Thanks,

-- 
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Internet Initiative Japan Inc.

Device Engineering Section,
IoT Platform Development Department,
Network Division,
Technology Unit

Kengo NAKAHARA <k-nakahara%iij.ad.jp@localhost>