FT-over-DS is a way to do a Fast BSS Transition using action frames for
the authenticate step. This allows a station to start a fast transition
to a target AP while still being connected to the original AP. This,
in theory, can result in less carrier downtime.
The existing ft_sm_new was removed, and two new constructors were added;
one for over-air, and another for over-ds. The internals of ft.c mostly
remain the same. A flag to distinguish between air/ds was added along
with a new parser to parse the action frames rather than authenticate
frames. The IE parsing is identical.
Netdev now just initializes the auth-proto differently depending on if
its doing over-air or over-ds. A new TX authenticate function was added
and used for over-ds. This will send out the IEs from ft.c with an
FT Request action frame.
The FT Response action frame is then recieved from the AP and fed into
the auth-proto state machine. After this point ft-over-ds behaves the
same as ft-over-air (associate to the target AP).
Some simple code was added in station.c to determine if over-air or
over-ds should be used. FT-over-DS can be beneficial in cases where the
AP is directing us to roam, or if the RSSI falls below a threshold.
It should not be used if we have lost communication to the AP all
(beacon lost) as it only works while we can still talk to the original
AP.
wiphy_select_akm needed to be updated to take a flag, which can be
set to true if there are known reauth keys for this connection. If
we have reauth keys, and FILS is available we will choose it.
Quick scan uses a set of frequencies associated with the
known networks. This allows to reduce the scan latency.
At this time, the frequency selection follows a very simple
logic by taking all known frequencies from the top 5 most
recently connected networks.
If connection isn't established after the quick scan attempt,
we fall back to the full periodic scan.
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.
The auto-connect state will now consist of the two phases:
STATION_STATE_AUTOCONNECT_QUICK and STATION_STATE_AUTOCONNECT_FULL.
The auto-connect will always start with STATION_STATE_AUTOCONNECT_QUICK
and then transition into STATION_STATE_AUTOCONNECT_FULL if no
connection has been established. During STATION_STATE_AUTOCONNECT_QUICK
phase we take advantage of the wireless scans with the limited number
of channels on which the known networks have been observed before.
This approach allows to shorten the time required for the network
sweeps, therefore decreases the connection latency if the connection
is possible. Thereafter, if no connection has been established after
the first phase we transition into STATION_STATE_AUTOCONNECT_FULL and
do the periodic scan just like we did before the split in
STATION_STATE_AUTOCONNECT state.
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.
Several Auth/Assoc failure status codes indicate that the connection
failed for reasons such as bandwidth issues, poor channel conditions
etc. These conditions should not result in the BSS being blacklisted
since its likely only a temporary issue and the AP is not actually
"broken" per-se.
This adds support in station.c to temporarily blacklist these BSS's
on a per-network basis. After the connection has completed we clear
out these blacklist entries.
Several netdev events benefit from including event data in the callback.
This is similar to how the connect callback works as well. The content
of the event data is documented in netdev.h (netdev_event_func_t).
By including event data for the two disconnect events, we can pass the
reason code to better handle the failure in station.c. Now, inside
station_disconnect_event, we still check if there is a pending connection,
and if so we can call the connect callback directly with HANDSHAKE_FAILED.
Doing it this way unifies the code path into a single switch statment to
handle all failures.
In addition, we pass the RSSI level index as event data to
RSSI_LEVEL_NOTIFY. This removes the need for a getter to be exposed in
netdev.h.
This change cleans up the mess of status vs reason codes. The two
types of codes have already been separated into different enumerations,
but netdev was still treating them the same (with last_status_code).
A new 'event_data' argument was added to the connect callback, which
has a different meaning depending on the result of the connection
(described inside netdev.h, netdev_connect_cb_t). This allows for the
removal of netdev_get_last_status_code since the status or reason
code is now passed via event_data.
Inside the netdev object last_status_code was renamed to last_code, for
the purpose of storing either status or reason. This is only used when
a disconnect needs to be emitted before failing the connection. In all
other cases we just pass the code directly into the connect_cb and do
not store it.
All ocurrences of netdev_connect_failed were updated to use the proper
code depending on the netdev result. Most of these simply changed from
REASON_CODE_UNSPECIFIED to STATUS_CODE_UNSPECIFIED. This was simply for
consistency (both codes have the same value).
netdev_[authenticate|associate]_event's were updated to parse the
status code and, if present, use that if their was a failure rather
than defaulting to UNSPECIFIED.
If we have a BSS list where all BSS's have been blacklisted we still
need a way to force a connection to that network, instead of having
to wait for the blacklist entry to expire. network_bss_select now
takes a boolean 'fallback_to_blacklist' which causes the selection
to still return a connectable BSS even if the entire list was
blacklisted.
In most cases this is set to true, as these cases are initiated by
DBus calls. The only case where this is not true is inside
station_try_next_bss, where we do want to honor the blacklist.
This both prevents an explicit connect call (where all BSS's are
blacklisted) from trying all the blacklisted BSS's, as well as the
autoconnect case where we simply should not try to connect if all
the BSS's are blacklisted.
There are is some implied behavior here that may not be obvious:
On an explicit DBus connect call IWD will attempt to connect to
any non-blacklisted BSS found under the network. If unsuccessful,
the current BSS will be blacklisted and IWD will try the next
in the list. This will repeat until all BSS's are blacklisted,
and in this case the connect call will fail.
If a connect is tried again when all BSS's are blacklisted IWD
will attempt to connect to the first connectable blacklisted
BSS, and if this fails the connect call will fail. No more
connection attempts will happen until the next DBus call.
If IWD fails to connect to a BSS we can attempt to connect to a different
BSS under the same network and blacklist the first BSS. In the case of an
incorrect PSK (MMPDU code 2 or 23) we will still fail the connection.
station_connect_cb was refactored to better handle the dbus case. Now the
netdev result switch statement is handled before deciding whether to send
a dbus reply. This allows for both cases where we are trying to connect
to the next BSS in autoconnect, as well as in the dbus case.
This makes __station_connect_network even less intelligent by JUST
making it connect to a network, without any state changes. This makes
the rekey logic much cleaner.
We were also changing dbus properties when setting the state to
CONNECTING, so those dbus property change calls were moved into
station_enter_state.
A new driver extended feature bit was added signifying if the driver
supports PTK replacement/rekeying. During a connect, netdev checks
for the driver feature and sets the handshakes 'no_rekey' flag
accordingly.
At some point the AP will decide to rekey which is handled inside
eapol. If no_rekey is unset we rekey as normal and the connection
remains open. If we have set no_rekey eapol will emit
HANDSHAKE_EVENT_REKEY_FAILED, which is now caught inside station. If
this happens our only choice is to fully disconnect and reconnect.
The changes to station.c are minor. Specifically,
station_build_handshake_rsn was modified to always build up the RSN
information, not just for SECURITY_8021X and SECURITY_PSK. This is
because OWE needs this RSN information, even though it is still
SECURITY_NONE. Since "regular" open networks don't need this, a check
was added (security == NONE && akm != OWE) which skips the RSN
building.
netdev.c needed to be changed in nearly the same manor as it was for
SAE. When connecting, we check if the AKM is for OWE, and if so create
a new OWE SM and start it. OWE handles all the ECDH, and netdev handles
sending CMD_AUTHENTICATE and CMD_ASSOCIATE when triggered by OWE. The
incoming authenticate/associate events just get forwarded to OWE as they
do with SAE.
During the handshake setup, if security != SECURITY_PSK then 8021x settings
would get set in the handshake object. This didn't appear to break anything
(e.g. Open/WEP) but its better to explicitly check that we are setting up
an 8021x network.
A sorted list of hidden network BSSs observed in the recent scan
is kept for the informational purposes of the clients. In addition,
it has deprecated the usage of seen_hidden_networks variable.
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.
This is a replacement for station's static select_akm_suite. This was
done because wiphy can make a much more intellegent decision about the
akm suite by checking the wiphy supported features e.g. SAE support.
This allows a connection to hybrid WPA2/WPA3 AP's if SAE is not
supported in the kernel.
As a consequence of the previous commit, netdev watches are always
called when the device object is valid. As a result, we can drop the
netdev_get_device calls and checks from individual AP/AdHoc/Station/WSC
netdev watches
Instead of creating the Station interface in device.c create it directly
on the netdev watch event the same way that the AP and AdHoc interfaces
are created and freed. This fixes some minor incosistencies, for
example station_free was previously called twice, once from device.c and
once from the netdev watch.
device.c would previously keep the pointer returned by station_create()
but that pointer was not actually useful so remove it. Autotests still
seem to pass.
Call netdev_disconnect() to make netdev forget any of station.c's
callbacks for connections or transitions in progress or established.
Otherwise station.c will crash as soon as we're connected and try to
change interface mode:
==17601== Invalid read of size 8
==17601== at 0x11DFA0: station_disconnect_event (station.c:775)
==17601== by 0x11DFA0: station_netdev_event (station.c:1570)
==17601== by 0x115D18: netdev_disconnect_event (netdev.c:868)
==17601== by 0x115D18: netdev_mlme_notify (netdev.c:3403)
==17601== by 0x14E287: l_queue_foreach (queue.c:441)
==17601== by 0x1558B4: process_multicast (genl.c:469)
==17601== by 0x1558B4: received_data (genl.c:532)
==17601== by 0x152888: io_callback (io.c:123)
==17601== by 0x151BCD: l_main_iterate (main.c:376)
==17601== by 0x151C9B: l_main_run (main.c:423)
==17601== by 0x10FE20: main (main.c:489)
Boiled down, FT over SAE is no different than FT over PSK, apart from
the different AKM suite. The bulk of this change fixes the current
netdev/station logic related to SAE by rebuilding the RSNE and adding
the MDE if present in the handshake to match what the PSK logic does.
A common function was introduced into station which will rebuild the
handshake rsne's for a target network. This is used for both new
network connections as well as fast transitions.
To prepare for FT over SAE, several case/if statements needed to include
IE_RSN_AKM_SUITE_FT_OVER_SAE. Also a new macro was introduced to remove
duplicate if statement code checking for both FT_OVER_SAE and SAE AKM's.
The ifindex as reported by netdev is unsigned, so make sure that it is
printed as such. It is astronomically unlikely that this causes any
actual issues, but lets be paranoid.
Move the roam initiation (signal loss, ap directed roaming) and scanning
details into station from device. Certain device functions have been
exposed temporarily to make this possible.
