UPnP device architecture specification requires all evented variables to
be included in the initial event message after subscription. Since this
can happen before we have seen any events, generated a dummy event
(WSC_ACK with all-zeros nonces) if needed.
This will notify control points of the services going away and allows
them to notice this without having to wait timeout on the
initial advertisements.
This is the first step in adding support for using wpa_supplicant as a
WPS External Registrar to manage APs over UPnP. Only the device
discovery part is implemented in this commit.
This adds mostly feature complete external Registrar support with the
main missing part being proper support for multiple external Registrars
working at the same time and processing of concurrent registrations when
using an external Registrar.
This code is based on Sony/Saice implementation
(https://www.saice-wpsnfc.bz/) and the changes made by Ted Merrill
(Atheros) to make it more suitable for hostapd design and embedded
systems. Some of the UPnP code is based on Intel's libupnp. Copyrights
and licensing are explained in src/wps/wps_upnp.c in more detail.
