Previously, the scan results were disregarded once the new
ones were available. To enable the scan scenarios where the
new scan results are delivered in parts, we introduce a
concept of aging BSSs and will remove them based on
retention time.
This is not used by any of the scan notify callback implementations and
for P2P we're going to need to scan on an interface without an ifindex
so without this the other changes should be mostly contained in scan.
This adds support for parsing the VHT IE, which allows a BSS supporting
VHT (80211ac) to be ranked higher than a BSS supporting only HT/basic
rates. Now, with basic/HT/VHT parsing we can calculate the theoretical
maximum data rate for all three and rank the BSS based on that.
This adds HT IE parsing and data rate calculation for HT (80211n)
rates. Now, a BSS supporting HT rates will be ranked higher than
a basic rate BSS, assuming the RSSI is at an acceptable level.
The spec dictates RSSI thresholds for different modulation schemes, which
correlate to different data rates. Until now were were ranking a BSS with
only looking at its advertised data rate, which may not even be possible
if the RSSI does not meet the threshold.
Now, RSSI is taken into consideration and the data rate returned from
parsing (Ext) Supported Rates IE(s) will reflect that.
If there are Ad-hoc BSSes they should be present in the scan results
together with regular APs as far as scan.c is concerned. But in
station mode we can't connect to them -- the Connect method will fail and
autoconnect would fail. Since we have no property to indicate a
network is an IBSS just filter these results out for now. There are
perhaps better solutions but the benefit is very low.
Pass an additional parameter to the scan results notify functions to
tell them whether the scan was successful. If it wasn't don't bother
passing an empty bss_list queue, pass NULL as bss_list. This way the
callbacks can tell whether the scan indicates there are no BSSes in
range or simply was aborted and the old scan results should be kept.
Add a flush flag to scan_parameters to tell the kernel to flush the
cache of scan results before the new scan. Use this flag in the
active scan during roaming.
Add a version of scan_active that accepts a struct with the scan
parameters so we can more easily add new parameters. Since the genl
message is now built within scan_active_start the extra_ie memory
can be freed by the caller at any time.
Don't decide on the AKM suite to use when the bss entries are received
and processed, instead select the suite when the connection is triggered
using a new function device_select_akm_suite, similar to
wiphy_select_cipher(). Describing the AKM suite through flags will be
more difficult when more than 2 suites per security type are supported.
Also handle the wiphy_select_cipher 0 return value when no cipher can be
selected.
In many cases the pairwise and group cipher information is not the only
information needed from the BSS RSN/WPA elements in order to make a
decision. For example, th MFPC/MFPR bits might be needed, or
pre-authentication capability bits, group management ciphers, etc.
This patch refactors bss_get_supported_ciphers into the more general
scan_bss_get_rsn_info function
This function takes an Operating Channel and a Country String to convert
it into a band. Using scan_oper_class_to_band and scan_channel_to_freq,
an Operating Channel, a Country String and a Channel Number together can
be converted into an actual frequency. EU and US country codes based on
wpa_supplicant's tables.
Tim Kourt