iproute2: add l2spec_type param to l2tp add session

When unmanaged L2TP sessions are created using "ip l2tp add session",
there is no option to allow the session's Layer2SpecificHeader type to
be selected - the kernel's default setting is always used. For
interopability with some vendor equipment, it might be necessary to
use a different setting. So add a new l2spec_type parameter to the "ip
l2tp add session" parameter list, allowing operators to set a specific
Layer2SpecificHeader type. The kernel already exposes the setting as a
netlink attribute so it is straightforward to add support for it in

This change allows unmanaged L2TP sessions to be configured between
Linux and some Cisco equipment by specifying "l2spec_type none" in "ip
l2tp add session" command parameters.

Signed-off-by: James Chapman <jchapman@katalix.com>
1 file changed