to be compliant with UPnP UDA 1.0, 1.1 and 2.0
fixes#698
UDA 1.0 1.2.3 Discovery: Search: Response (p21) :
CACHE-CONTROL
Required. Must have max-age directive that specifies number of seconds
the advertisement is valid. After this duration, control points should
assume the device (or service) is no longer available. Should be greater
than or equal to 1800 seconds (30 minutes), although exceptions are defined
in the text above. Specified by UPnP vendor. Integer.
UDA 1.1 1.3.3 Search response (p34) :
CACHE-CONTROL
REQUIRED. Field value MUST have the max-age directive (“max-age=”) followed
by an integer that specifies the number of seconds the advertisement
is valid. After this duration, control points SHOULD assume the device
(or service) is no longer available; as long as a control point has
received at least one advertisement that is still valid from a root
device, any of its embedded devices or any of its services, then the
control point can assume that all are available. The number of seconds
SHOULD be greater than or equal to 1800 seconds (30 minutes), although
exceptions are defined in the text above. Specified by UPnP vendor.
Other directives MUST NOT be sent and MUST be ignored when received.
UDA 2.0 1.3.3 Search response (p40) :
CACHE-CONTROL
Required. Field value shall have the max-age directive (“max-age=”) followed
by an integer that specifies the number of seconds the advertisement
is valid. After this duration, control points should assume the device
(or service) is no longer available; as long as a control point has
received at least one advertisement that is still valid from a root
device, any of its embedded devices or any of its services, then the
control point can assume that all are available. The number of seconds
should be greater than or equal to 1800 seconds (30 minutes), although
exceptions are defined in the text above. Specified by UPnP vendor.
Other directives shall not be sent and shall be ignored when received.
upnp_update_inboundpinhole() takes the leasetime as an argument,
not the timestamp (= current_time + leasetime).
That was resulting in havin a timestamp very far in the future
see https://miniupnp.tuxfamily.org/forum/viewtopic.php?p=5840#
