If IWD is connecting to a SAE/WPA3 BSS and Auth/Assoc commands
are not supported the only option is SAE offload. At this point
network_connect should have verified that the extended feature
for SAE offload exists so we can simply enable offload if these
commands are not supported.
If the hardware roams automatically we want to be sure to not
react to CQM events and attempt to roam/disconnect on our own.
Note: this is only important for very new kernels where CQM
events were recently added to brcmfmac.
Roaming on a full mac card is quite different than soft mac
and needs to be specially handled. The process starts with
the CMD_ROAM event, which tells us the driver is already
roamed and associated with a new AP. After this it expects
the 4-way handshake to be initiated. This in itself is quite
simple, the complexity comes with how this is piped into IWD.
After CMD_ROAM fires its assumed that a scan result is
available in the kernel, which is obtained using a newly
added scan API scan_get_firmware_scan. The only special
bit of this is that it does not 'schedule' a scan but simply
calls GET_SCAN. This is treated special and will not be
queued behind any other pending scan requests. This lets us
reuse some parsing code paths in scan and initialize a
scan_bss object which ultimately gets handed to station so
it can update connected_bss/bss_list.
For consistency station must also transition to a roaming state.
Since this roam is all handled by netdev two new events were
added, NETDEV_EVENT_ROAMING and NETDEV_EVENT_ROAMED. Both allow
station to transition between roaming/connected states, and ROAMED
provides station with the new scan_bss to replace connected_bss.
An earlier patch fixed a problem where a queued quick scan would
be triggered and fail once already connected, resulting in a state
transition from connected --> autoconnect_full. This fixed the
Connect() path but this could also happen via autoconnect. Starting
from a connected state, the sequence goes:
- DBus scan is triggered
- AP disconnects IWD
- State transition from disconnected --> autoconnect_quick
- Queue quick scan
- DBus scan results come in and used to autoconnect
- A connect work item is inserted ahead of all others, transition
from autoconnect_quick --> connecting.
- Connect completes, transition from connecting --> connected
- Quick scan can finally get triggered, which the kernel fails to
do since IWD is connected, transition from connected -->
autoconnect_full.
This can be fixed by checking for a pending quick scan in the
autoconnect path.
Commit eac2410c83 ("station: Take scanned frequencies into account")
has made it unnecessary to explicitly invoke station_set_scan_results
with the expire to true in case a dbus scan finished prematurely or a
subset was not able to be started. Remove this no-longer needed logic.
Fixes: eac2410c83 ("station: Take scanned frequencies into account")
The diagnostic interface returns an error anyways if station is
not connected so it makes more sense to only bring the interface
up when its actually usable. This also removes the interface
when station disconnects, which was never done before (the
interface stayed up indefinitely due to a forgotten remove call).
When we're auto-connecting and have hidden networks configured, use
active scans regardless of whether we see any hidden BSSes in our
existing scan results.
This allows us to more effectively see/connect to hidden networks
when first powering up or after suspend.
Kernel might report hidden BSSes that are reported from beacon frames
separately than ones reported due to probe responses. This may confuse
the station network collation logic since the scan_bss generated by the
probe response might be removed erroneously when processing the scan_bss
that was generated due to a beacon.
Make sure that bss_match also takes the SSID into account and only
matches scan_bss structures that have the same BSSID and SSID contents.
Instead of manually managing whether to expire BSSes or not, use the
scanned frequency set instead. This makes the API slightly easier to
understand (dropping two boolean arguments in a row) and also a bit more
future-proof.
Commit d372d59bea checks whether a hidden network had a previous
connection attempt and re-tries. However, it inadvertently dropped
handling of a condition where a non-hidden network SSID is provided to
ConnectHiddenNetwork. Fix that.
Fixes: d372d59bea ("station: Allow ConnectHiddenNetwork to be retried")
Now that ConnectHiddenNetwork can be invoked while we're connected, set
the mac randomization hint parameter properly. The kernel will reject
requests if randomization is enabled while we're connected to a network.
If we forget a hidden network, then make sure to remove it from the
network list completely. Otherwise it would be possible to still
issue a Network.Connect to that particular object, but the fact that the
network is hidden would be lost.
==17639== 72 (16 direct, 56 indirect) bytes in 1 blocks are definitely
lost in loss record 3 of 3
==17639== at 0x4C2F0CF: malloc (vg_replace_malloc.c:299)
==17639== by 0x4670AD: l_malloc (util.c:61)
==17639== by 0x4215AA: scan_freq_set_new (scan.c:1906)
==17639== by 0x412A9C: parse_neighbor_report (station.c:1910)
==17639== by 0x407335: netdev_neighbor_report_frame_event
(netdev.c:3522)
==17639== by 0x44BBE6: frame_watch_unicast_notify (frame-xchg.c:233)
==17639== by 0x470C04: dispatch_unicast_watches (genl.c:961)
==17639== by 0x470C04: process_unicast (genl.c:980)
==17639== by 0x470C04: received_data (genl.c:1101)
==17639== by 0x46D9DB: io_callback (io.c:118)
==17639== by 0x46CC0C: l_main_iterate (main.c:477)
==17639== by 0x46CCDB: l_main_run (main.c:524)
==17639== by 0x46CF01: l_main_run_with_signal (main.c:656)
==17639== by 0x403EDE: main (main.c:490)
In the case that ConnectHiddenNetwork scans successfully, but fails for
some other reason, the network object is left in the scan results until
it expires. This will prevent subsequent attempts to use
ConnectHiddenNetwork with a .NotHidden error. Fix that by checking
whether a found network is hidden, and if so, allow the request to
proceed.
Rework the logic slightly so that this function returns an error message
on error and NULL on success, just like other D-Bus method
implementations. This also simplifies the code slightly.
We used to not allow to connect to a different network while already
connected. One had to disconnect first. This also applied to
ConnectHiddenNetwork calls.
This restriction can be dropped now. station will intelligently
disconnect from the current AP when a station_connect_network() is
issued.
If the disconnect fails and station_disconnect_onconnect_cb is called
with an error, we reply to the original message accordingly.
Unfortunately pending_connect is not unrefed or cleared in this case.
Fix that.
Fixes: d0ee923dda ("station: Disconnect, if needed, on a new connection attempt")
At some point the non-interactive client tests began failing.
This was due to a bug in station where it would transition from
'connected' to 'autoconnect' due to a failed scan request. This
happened because a quick scan got scheduled during an ongoing
scan, then a Connect() gets issued. The work queue treats the
Connect as a priority so it delays the quick scan until after the
connection succeeds. This results in a failed quick scan which
IWD does not expect to happen when in a 'connected' state. This
failed scan actually triggers a state transition which then
gets IWD into a strange state where its connected from the
kernel point of view but does not think it is:
src/station.c:station_connect_cb() 13, result: 0
src/station.c:station_enter_state() Old State: connecting, new state: connected
src/wiphy.c:wiphy_radio_work_done() Work item 6 done
src/wiphy.c:wiphy_radio_work_next() Starting work item 5
src/station.c:station_quick_scan_triggered() Quick scan trigger failed: -95
src/station.c:station_enter_state() Old State: connected, new state: autoconnect_full
To fix this IWD should simply cancel any pending quick scans
if/when a Connect() call comes in.
With AP now getting its own diagnostic interface it made sense
to move the netdev_station_info struct definition into its own
header which eventually can be accompanied by utilities in
diagnostic.c. These utilities can then be shared with AP and
station as needed.
Following a successful roaming sequence, schedule another attempt unless
the driver has sent a high RSSI notification. This makes the behaviour
analogous to a failed roaming attempt where we remained connected to the
same BSS.
This makes iwd compatible with wireless drivers which do not necessarily
send out a duplicate low RSSI notification upon reassociation. Without
this change, iwd risks getting indefinitely stuck to a BSS with low
signal strength, even though a better BSS might later become available.
In the case of a high RSSI notification, the minimum roam time will also
be reset to zero. This preserves the original behaviour in the case
where a high RSSI notification is processed after station_roamed().
Doing so also gives a chance for faster roaming action in the following
example scenario:
1. RSSI LOW
2. schedule roam in 5 seconds
(5 seconds pass)
3. try roaming
4. roaming fails, same BSS
5. schedule roam in 60 seconds
(20 seconds pass)
6. RSSI HIGH
7. cancel scheduled roam
(20 seconds pass)
8. RSSI LOW
9. schedule roam in 5 seconds or 20 seconds?
By resetting the minimum roam time, we can avoid waiting 20 seconds when
the station may have moved considerably. And since the high/low RSSI
notifications are configured with a hysteresis, we should still be
protected against too frequent spurious roaming attempts.
Add a parameter to station_set_scan_results to allow skipping the
removal of old BSSes. In the DBus-triggered scan only expire BSSes
after having gone through the full supported frequency set.
It should be safe to pass partial scan results to
station_set_scan_results() when not expiring BSSes so using this new
parameter I guess we could also call it for roam scan results.
A scan normally takes about 2 seconds on my dual-band wifi adapter when
connected. The drivers will normally probe on each supported channel in
some unspecified order and will have new partial results after each step
but the kernel sends NL80211_CMD_NEW_SCAN_RESULTS only when the full
scan request finishes, and for segmented scans we will wait for all
segments to finish before calling back from scan_active() or
scan_passive().
To improve user experience define our own channel order favouring the
2.4 channels 1, 6 and 11 and probe those as an individual scan request
so we can update most our DBus org.connman.iwd.Network objects more
quickly, before continuing with 5GHz band channels, updating DBus
objects again and finally the other 2.4GHz band channels.
The overall DBus-triggered scan on my wifi adapter takes about the same
time but my measurements were not very strict, and were not very
consistent with and without this change. With the change most Network
objects are updated after about 200ms though, meaning that I get most
of the network updates in the nm-applet UI 200ms from opening the
network list. The 5GHz band channels take another 1 to 1.5s to scan and
remaining 2.4GHz band channels another ~300ms.
Hopefully this is similar when using other drivers although I can easily
imagine a driver that parallelizes 2.4GHz and 5GHz channel probing using
two radios, or uses 2, 4 or another number of dual-band radios to probe
2, 4, ... channels simultanously. We'd then lose some of the
performance benefit. The faster scan results may be worth the longer
overall scan time anyway.
I'm also assuming that the wiphy's supported frequency list is exactly
what was scanned when we passed no frequency list to
NL80211_CMD_TRIGGER_SCAN and we won't get errors for passing some
frequency that shouldn't have been scanned.
Waiting to request neighbor reports until we are in need of a roam
delays the roam time, and probably isn't as reliable since we are
most likely in a low RSSI state. Instead the neighbor report can
be requested immediately after connecting, saved, and used if/when
a roam is needed. The existing behavior is maintained if the early
neighbor report fails where a neighbor report is requested at the
time of the roam.
The code which parses the reports was factored out and shared
between the existing (late) neighbor report callback and the early
neighbor report callback.
Modern kernels ~5.4+ have changed the way lost beacons are
reported and effectively make the lost beacon event useless
because it is immediately followed by a disconnect event. This
does not allow IWD enough time to do much of anything before
the disconnect comes in and we are forced to fully re-connect
to a different AP.
periodic_scan_stop is called whenever we exit the autoscan state but a
periodic scan may not be running at the time. If we have a
user-triggered scan running, or the autoconnect_quick scan, and we reset
Scanning to false before that scan finished, a client could en up
calling GetOrderedNetwork too early and not receiving the scan results.
ConnectHiddenNetwork can be seen a triggering this sequence:
1. the active scan,
2. the optional agent request,
3. the Authentication/Association/4-Way Handshake/netconfig,
4. connected state
Currently Disconnect() interrupts 3 and 4, allow it to also interrupt
state 1. It's difficult to tell whether we're in state 2 from within
station.c.
For multi-bss networks its nice to know which BSS is being connected
to. The ranking can hint at it, but blacklisting or network capabilities
could effect which network is actually chosen. An explicit debug print
makes debugging much easier.
Move the update of station->networks_sorted order to before we set
station->connected_network NULL to avoid a crash when we attempt to
use the NULL pointer.
Besides being undefined behaviour, signed integer overflow can cause
unexpected comparison results. In the case of network_rank_compare(),
a connected network with rank INT_MAX would cause newly inserted
networks with negative rank to be inserted earlier in the ordered
network list. This is reflected in the GetOrderedMethods() DBus method
as can be seen in the following iwctl output:
[iwd]# station wlan0 get-networks
Network name Security Signal
----------------------------------------------------
BEOLAN 8021x **** }
BeoBlue psk *** } all unknown,
UI_Test_Network psk *** } hence assigned
deneb_2G psk *** } negative rank
BEOGUEST open **** }
> titan psk ****
Linksys05274_5GHz_dmt psk ****
Lyngby-4G-4 5GHz psk ****
Doing so ensures that the currently connected network is always at the
beginning of the list. Previously, the list would only get updated after
a scan.
This fixes the documented behaviour of GetOrderedNetworks() DBus method,
which states that the currently connected network is always at the
beginning of the returned array.
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.
Before connecting to a hidden network we must scan. During this scan
if another connection attempt comes in the expected behavior is to
abort the original connection. Rather than waiting for the scan to
complete, then canceling the original hidden connection we can just
cancel the hidden scan immediately, reply to dbus, and continue with
the new connection attempt.
The new frame-xchg module now handles a lot of what ANQP used to do. ANQP
now does not need to depend on nl80211/netdev for building and sending
frames. It also no longer needs any of the request lookups, frame watches
or to maintain a queue of requests because frame-xchg filters this for us.
From an API perspective:
- anqp_request() was changed to take the wdev_id rather than ifindex.
- anqp_cancel() was added so that station can properly clean up ANQP
requests if the device disappears.
During testing a bug was also fixed in station on the timeout path
where the request queue would get popped twice.
When roaming, iwd tries to scan a limited number of frequencies to keep
the roaming latency down. Ideally the frequency list would come in from
a neighbor report, but if neighbor reports are not supported, we fall
back to our internal database for known frequencies of this network.
iwd tries to keep the number of scans down to a bare minimum, which
means that we might miss APs that are in range. This could happen
because the user might have moved physically and our frequency list is
no longer up to date, or if the AP frequencies have been reconfigured.
If a limited scan fails to find any good roaming candidates, re-attempt
a full scan right away.
James Prestwood