What I want is not to hide the SSID, but just to ignore broadcast probe requests
I'm thinking that parameter is not well named in hostapd, and better named in openwrt
hide_ssid sets ignore_broadcast_ssid to 1 in hostapd... so there is a type 2 for that parameter but I think it still hides ssid...
I'm in a busy area, and got an esp8266 running a probe sniffer and can see, at times, absolute floods of probes... most of them broadcast probes, well about 10,000 cars a day pass within 10 metres of the access point, and already a crowded wifi area.
Now, I am a high traffic user, lots of nodes, grabbing lots of images and data and streams (swiss radio and their 192kbit/s streams eh) across wifi, so part of the problem to an extent is my devices so been working to minimise my impact.
So, I got the pi's to passive scan, but with hide_ssid, those devices cannot see their own network and so do not connect, the reason I have them passive scanning is because if I take the wifi down overnight I discovered all my pi's are probing permanently and a lot... so can do scan_ssid in supplicant but still if the wifi is down still flooding probe requests. (up to 12 pi's on at once)
So what I would like is ignore broadcast probes but keep sending out the ssid in broadcasts, that way passive scanning on the client stops the probes until it sees a broadcast.
So could be a ignore_broadcast_ssid=3 type added to hostapd to just ignore broadcast_ssid probe requests, and leave the ssid in your own broadcasts.
But, I discovered you can pass extra hostapd parameters using
uci add_list wireless.radio1.hostapd_options="ignore_broadcast_ssid=2"
but when I checked it adds this at the top of hostapd, and it is then redefined again by the default openwrt set up of hostapd based on hide_ssid
(I have a hunch there is some trick involving probes to jack your connection on outlying weak signal nodes, so also why been looking into it... the raspberry pops up as wifi direct unless you physically disable the option in wpa_supplicant (though that should be default), so spotted and fixed that, but may still be a window of opportunity, because still seeing probe requests when you would not expect them, and observing with my esp8266 device rssi of some probes different to suspicious probes.... so working on a wifi guard chip idea for esp-01 which are quite good little devices)
but anyway, just to ignore broadcast probes would save some traffic...
I mean I have not really got time for this "Spy vs. Spy" crap, but makes you realise how dependent on wi-fi you are.... and as that seems to be the name of the game... war for the nature of the world eh!
an interesting dichotomy, either your nodes start announcing here I am looking for this AP when the AP is not available with scan_ssid set in wpa_supplicant or they are quiet when AP not available with passive_scan but you cannot ignore broadcast probes to the AP on the AP