Specifically OWE networks with multiple open/hidden BSS's are troublesome
to scan for with the current APIs. The scan parameters are limited to a
single SSID and even if that was changed we have the potential of hitting
the max SSID's per scan limit. In all, it puts the burden onto the caller
to sort out the SSIDs/frequencies to scan for.
Rather than requiring station to handle this a new scan API was added,
scan_owe_hidden() which takes a list of open BSS's and will automatically
scan for the SSIDs in the OWE transition IE for each.
It is slightly optimized to first check if all the hidden SSID's are the
same. This is the most likely case (e.g. single pair or single network)
and a single scan command can be used. Otherwise individual scan commands
are queued for each SSID/frequency combo.
IWD has restricted SSIDs to only utf8 so they can be displayed but
with the addition of OWE transition networks this is an unneeded
restriction (for these networks). The SSID of an OWE transition
network is never displayed to the user so limiting to utf8 isn't
required.
Allow non-utf8 SSIDs to be scanned for by including the length in
the scan parameters and not relying on strlen().
Adds support for getting firmware scan results from the kernel.
This is intended to be used after the firmware roamed automatically
and the scan result is require for handshake initialization.
The scan 'request' is competely separate from the normal scan
queue, though scan_results, scan_request, and the scan_context
are all used for consistency and code reuse.
Handle situations where the BSS we're trying to connect to is no longer
in the kernel scan result cache. Normally, the kernel will re-scan the
target frequency if this happens on the CMD_CONNECT path, and retry the
connection.
Unfortunately, CMD_AUTHENTICATE path used for WPA3, OWE and FILS does
not have this scanning behavior. CMD_AUTHENTICATE simply fails with
a -ENOENT error. Work around this by trying a limited scan of the
target frequency and re-trying CMD_AUTHENTICATE once.
To use the wiphy radio work queue, scanning mostly remained the same.
start_next_scan_request was modified to be used as the work callback,
as well as not start the next scan if the current one was done
(since this is taken care of by wiphy work queue now). All
calls to start_next_scan_request were removed, and more or less
replaced with wiphy_radio_work_done.
scan_{suspend,resume} were both removed since radio management
priorities solve this for us. ANQP requests can be inserted ahead of
scan requests, which accomplishes the same thing.
Save the source frame type in struct scan_bss as it may affect how some
of the data in the struct will be parsed. Also replace the P2P IE
payload data in that struct with a union containing pre-parsed p2p
attributes corresponding to the frame type.
This means users don't have to call the parsers in p2putil.c on that
data, which wouldn't have worked anyway because those parsers assume
input is the raw IE sequence rather than just the "payload".
The kernel sends NL80211_ATTR_SCAN_START_TIME_TSF with CMD_TRIGGER and
RRM requires this value for beacon measurement reports.
The start time is parsed during CMD_TRIGGER and set into the scan request.
A getter was added to obtain this time value for an already triggered
scan.
After making the change, the SCAN_ABORTED case was cleaned up a bit to
remove the local scan_request usage in favor of the one used for all the
other cases.
The kernel allows a scan duration and duration mandatory flag to be
set in scan requests. RRM requests can contain these values so they
have been added to scan_parameters.
Scanning with drivers which do not support EXT_FEATURE_SET_SCAN_DWELL
will not include these values in scan requests.
For (Re)Association the HS20 indication element was passed exactly as
it was found in the scan results. The spec defines what bits can be
set and what cannot when this IE is used in (Re)Association. Instead
of assuming the AP's IE conforms to the spec, we now parse the IE and
re-build it for use with (Re)Association.
Since the full IE is no longer used, it was removed from scan_bss, and
replaced with a bit for HS20 support (hs20_capable). This member is
now used the same as hs20_ie was.
The version parsed during scan results is now used when building the
(Re)Association IE.
The HS20 indication element should always be included during
(Re)Association per the spec. This removes the need for a
dedicated boolean, and now the hs20_ie can be used instead.
P2P probe requests are to be sent at min 6.0 Mb/s using OFDM,
specifically the 802.11b rates are prohibited (section 2.4.1 in Wi-Fi
P2p Technical Spec v1.7), some of which use CCK modulation. This is
already the default for 5G but for 2.4G the drivers generally do this
if we set the NL80211_ATTR_TX_NO_CCK_RATE flags with
NL80211_CMD_TRIGGER_SCAN.
The ifindex is used to index the netdevs in the system (wlan, ethernet,
etc.) but we can also do wifi scanning on interfaces that have no
corresponding netdev object, like the P2P-device virtual interfaces.
Use the wdev id's to reference interfaces, the nl80211 api doesn't care
whether we use a NL80211_ATTR_IFINDEX or NL80211_ATTR_WDEV. Only
wireless interfaces have a wdev id.
In order to do ANQP efficiently IWD needs the ability to suspend scanning
temporarily. This is because both scanning and ANQP go offchannel and must
remain off channel for some amount of time. This cannot be done
simultaneously and if e.g. ANQP is requested after a scan is already
pending, the kernel will wait till that scan finishes before sending out
the frame.
This IE tells us what Advertisement Protocols the AP supports. This
is only here to look for ANQP support, so all this does is iterate
through all other Advertisement Protocol tuples looking for ANQP.
If found, anqp_capable is set in the scan_bss
The vendor specific IE was being parsed only to check if the AP supported
WPA, which used a Microsoft OUI. Hotspot/OSEN uses neither WPA or RSN
(although its nearly identical to RSN) so the we also need to check for
this Wifi-Alliance OUI and set bss->osen (new) if found.
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.
