This command uses GetDiagnostics to show a list of connected
clients and some information about them. The information
contained for each connected station nearly maps 1:1 with the
station diagnostics information shown in "station <wlan> show"
apart from "ConnectedBss" which is now "Address".
For now this module serves as a helper for printing diagnostic
dictionary values. The new API (diagnostic_display) takes a
Dbus iterator which has been entered into a dictionary and
prints out each key and value. A mapping struct was defined
which maps keys to types and units. For simple cases the mapping
will consist of a dbus type character and a units string,
e.g. dBm, Kbit/s etc. For more complex printing which requires
processing the value the 'units' void* cant be set to a
function which can be custom written to handle the value.
This adds a new AccessPointDiagnostic interface. This interface
provides similar low level functionality as StationDiagnostic, but
for when IWD is in AP mode. This uses netdev_get_all_stations
which will dump all stations, parse, and return each station in
an individual callback. Once the dump is complete the destroy is
called and all data is packaged as an array of dictionaries.
AP mode will use the same structure for its diagnostic interface
and mostly the same dictionary keys. Apart from ConnectedBss and
Address being different, the remainder are the same so the
diagnostic_station_info to DBus dictionary conversion has been made
common so both station and AP can use it to build its diagnostic
dictionaries.
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.
systemd specifies a special passive target unit 'network-pre.target'
which may be pulled in by services that want to run before any network
interface is brought up or configured. Correspondingly, network
management services such as iwd and ead should specify
After=network-pre.target to ensure a proper ordering with respect to
this special target. For more information on network-pre.target, see
systemd.special(7).
Two examples to explain the rationale of this change:
1. On one of our embedded systems running iwd, a oneshot service is
run on startup to configure - among other things - the MAC address of
the wireless network interface based on some data in an EEPROM.
Following the systemd documentation, the oneshot service specifies:
Before=network-pre.target
Wants=network-pre.target
... to ensure that it is run before any network management software
starts. In practice, before this change, iwd was starting up and
connecting to an AP before the service had finished. iwd would then
get kicked off by the AP when the MAC address got changed. By
specifying After=network-pre.target, systemd will take care to avoid
this situation.
2. An administrator may wish to use network-pre.target to ensure
firewall rules are applied before any network management software is
started. This use-case is described in the systemd documentation[1].
Since iwd can be used for IP configuration, it should also respect
the After=network-pre.target convention.
Note that network-pre.target is a passive unit that is only pulled in if
another unit specifies e.g. Wants=network-pre.target. If no such unit
exists, this change will have no effect on the order in which systemd
starts iwd or ead.
[1] https://www.freedesktop.org/wiki/Software/systemd/NetworkTarget/
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.
This takes a Dbus iterator which has been entered into a
dictionary and prints out each key and value. It requires
a mapping which maps keys to types and units. For simple
cases the mapping will consist of a dbus type character
and a units string, e.g. dBm, Kbit/s etc. For more complex
printing which requires processing the value the 'units'
void* cant be set to a function which can be custom written
to handle the value.
This is a nl80211 dump version of netdev_get_station aimed at
AP mode. This will dump all stations, parse into
netdev_station_info structs, and call the callback for each
individual station found. Once the dump is completed the destroy
callback is called.
The information requested with GetDiagnostics will now appear in
the "station <iface> show" command. If IWD is not connected, or
there is no diagnostic interface (older IWD version) 'show' will
behave as it always has, only showing scanning/connected.
Some elements, though unlikely, are not required to be included
with the GET_STATION call that GetDiagnostics relies on. mac80211
based drivers include most of these, but other drivers may not.
To be on the safe side all properties except ConnectedBss are now
optional and may not be included.
This adds a generalized API for GET_STATION. This API handles
calling and parsing the results into a new structure,
netdev_station_info. This results structure will hold any
data needed by consumers of netdev_get_station. A helper API
(netdev_get_current_station) was added as a convenience which
automatically passes handshake->aa as the MAC.
For now only the RSSI is parsed as this is already being
done for RSSI polling/events. Looking further more info will
be added such as rx/tx rates and estimated throughput.
Arrays of dictionaries are quite common, and for basic
types this API makes things much more convenient by
putting all the enter/append/leave calls in one place.
Retrieve the dependencies of readline through pkg-config (and fallback
to -lreadline) to avoid the following build failure:
/nvme/rc-buildroot-test/scripts/instance-0/output-1/host/opt/ext-toolchain/bin/../lib/gcc/x86_64-buildroot-linux-uclibc/8.3.0/../../../../x86_64-buildroot-linux-uclibc/bin/ld: /nvme/rc-buildroot-test/scripts/instance-0/output-1/host/bin/../x86_64-buildroot-linux-uclibc/sysroot/usr/lib/libreadline.a(display.o): in function `cr':
display.c:(.text+0x1ab): undefined reference to `tputs'
Fixes:
- http://autobuild.buildroot.org/results/8fb1341f2f5094c346456b43b4fc04996c2e1485
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.
Use the hwsim DBus API rather than command line. This both is
faster and more dynamic than doing so with the command line.
This also avoids tracking the radio ID since we can just hang
on to the radio Dbus object directly.
