Currently, if multiple bss share are bridge and tagged vlan interface,
only the first instance of struct hostapd_vlan for this vlanid will have
the DVLAN_CLEAN_VLAN flag added. Thus, when this instance is removed,
the tagged vlan interface will be removed from bridge, thought other bss
might still need it. Similarily, the bridge will be left over, as the
does not have zero ports when the first instance of a struct
hostapd_vlan is freed.
This patch fixes this by having a global (per process) reference counter
for dynamic tagged vlan and dynamically created bridge interfaces, so
they are only removed after all local users are freed. (struct
hapd_interfaces *)->vlan_priv is used to hold src/ap/vlan_init.c global
per-process data like drv_priv does; right now this is only used for the
interface reference counting, but could get extended when needed. Then
possibly some vlan_global_init / vlan_global_deinit should be added, but
this is not required right now.
Additionally, vlan->configured is checked to avoid reference counter
decreasing before vlan_newlink increased them.
In order to avoid race conditions, vlan_dellink is called explicitly
after hostapd_vlan_if_remove. Otherwise there would be a short timeframe
between hostapd_vlan_if_remove and vlan_dellink during which the struct
hostapd_vlan still exists, so ap_sta_bind_vlan would try to attach
stations to it.
Signed-off-by: Michael Braun <michael-dev@fami-braun.de>