On Wed, Apr 08, 2020 at 11:09:25AM -0500, Mariya Krovatkina wrote: > Our project team is planning to use hostapd to create a wifi access point > at the oilfield, but we've been having questions and concerns related to > regulatory compliance, as this will be enterprise use, not personal use. > I guess, we weren't able to find clear information on how hostapd deals > with the country settings and how the regulatory compliance information > is being updated. > So far I see at least 4 levels of where the impact can happen: > - NIC hardware - supported channels and modes > - NIC firmware > - Linux drivers (in our case brcmsmac) > - Hostapd configuration (uses nl80211 to configure the driver) It is the first three that are expected to enforce regulatory requirements. > 1. When we set a country and dot11CountryString, does hostapd use a certain > database with current regulatory details for the country and translate > to driver commands? hostapd notifies the driver about the configured country code and fetches the allowed channel list from the driver, so no, hostapd does not do such database processing; the database is in the driver (or well, somewhere in the kernel, e.g., in cfg80211 regulatory that can be shared by multiple drivers). > 2. Where is this database stored and can we update it if some unusual > country decides to change regulations (which happens quite rarely though)? That depends on the driver. It might be in cfg80211 and loaded from /lib/firmware/regulatory.db or built into the kernel image. Or it might be in the driver/firmware/hardware calibration data. > 3. Is it possible that hostapd will report the country as set correctly, > but the driver will not accept all of the settings, so resulting frequencies > on the NIC will not be compliant? hostapd will refuse to start AP if the configured channel is not shown as being available in the channel list fetched from the driver, but the main enforcement of non-compliant parameters is expected to be done in the driver. > 4. I think, worldwide regulatory domain is set on our NIC by default. > Will hostapd always be able to change it using the Country setting? > If not, will it impact the regulatory profile? That depends on the driver. Number of drivers enforce local configuration and refuse to enable new channels based on country code provided from user space. In such cases, the driver may, e.g., not allow any 5 GHz channels to be used if the hardware is configured to use worldwide roaming defaults. > 5. What troubleshooting commands can be helpful to make sure the right > profile is applied? (e.g. iw reg get, iw list, etc.) That's also driver specific, but looking at what those commands return is quite useful part of this for cfg80211-based drivers. -- Jouni Malinen PGP id EFC895FA _______________________________________________ Hostap mailing list Hostap@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/hostap
