Commit graph

29 commits

Author SHA1 Message Date
John Crispin
39b9d059cd HE: Remove vht_ prefix from acs_adjust_vht_center_freq()
This is used for both VHT and HE, so remove the misleading prefix.

Signed-off-by: Shashidhar Lakkavalli <slakkavalli@datto.com>
Signed-off-by: John Crispin <john@phrozen.org>
2019-05-27 16:30:05 +03:00
John Crispin
464dcfd030 HE: Remove VHT_ prefix from CHANWITDH_* define
The bandwidth values are shared between VHT and HE mode so remove the
VHT specific prefix.

Signed-off-by: Shashidhar Lakkavalli <slakkavalli@datto.com>
Signed-off-by: John Crispin <john@phrozen.org>
2019-05-27 16:27:49 +03:00
Dmitry Lebed
75ce63e063 ACS: Add supported channel bandwidth checking
While doing automatic channel selection we need to take into account
supported bandwidth for each channel provided via nl80211. Without this
modification hostapd might select an unsupported channel which would
fail during AP startup.

Signed-off-by: Dmitry Lebed <dlebed@quantenna.com>
2019-01-06 12:04:15 +02:00
Dmitry Lebed
22dcafc20c ACS: Add support for 160 MHz bandwidth
Add support for 160 MHz BW channels to automatic channel selection
algorithm. Only 36 and 100 channels are supported as 160 MHz channels.

Signed-off-by: Dmitry Lebed <lebed.dmitry@gmail.com>
2019-01-06 01:44:06 +02:00
Karthikeyan Periyasamy
c4dd3afa3c ACS: Avoid invalid interference factor when survey channel time is zero
When the channel time is zero the interference factor calculation falls
under divide by zero operation which results in invalid (NaN =
not-a-number) interference factor value. This leads to wrong ideal
channel selection in ACS during the scenario described below.

Scenario:

In VHT80 mode, the channel 36 (first channel) gets the channel time as
zero which causes the interfactor factor to be an invalid number (NaN).
Any operations (like addition, mulitplication, divide, etc.) with NaN
value results in a NaN value, so that average factor for the primary
channel 36 got the invalid value (NaN). Since channel 36 is the first
channel, ideal factor is assigned as NaN in the first iteration. The
following iteration condition check (factor < ideal_factor) with a NaN
value fail for all other primary channels. This results in channel 36
being chosen as the ideal channel in ACS which holds a NaN value.

Logs:

ACS: Survey analysis for channel 36 (5180 MHz)
ACS: 1: min_nf=-103 interference_factor=nan nf=0 time=0 busy=0 rx=0
ACS: 2: min_nf=-103 interference_factor=0.615385 nf=-102 time=13 busy=8 rx=0
ACS: 3: min_nf=-103 interference_factor=2.45455 nf=0 time=22 busy=16 rx=0
ACS: 4: min_nf=-103 interference_factor=0.785714 nf=-103 time=42 busy=33 rx=0
ACS: 5: min_nf=-103 interference_factor=nan nf=0 time=0 busy=0 rx=0
ACS:  * interference factor average: nan
...
ACS:  * channel 36: total interference = nan
..
ACS:  * channel 149: total interference = 5.93174e-21
..
ACS: Ideal channel is 36 (5180 MHz) with total interference factor of nan

Signed-off-by: Karthikeyan Periyasamy <periyasa@codeaurora.org>
2018-05-16 01:16:54 +03:00
Jouni Malinen
4c803dfcd7 ACS: Fix memory leak if interface is disabled during scan
The survey data was not freed if hostapd interface got disabled during
an ACS scan.

Signed-off-by: Jouni Malinen <j@w1.fi>
2017-03-04 17:30:15 +02:00
Jouni Malinen
29be2c090e ACS: Simplify code paths
This removes some unnecessarily duplicated return paths and simplifies
code paths.

Signed-off-by: Jouni Malinen <j@w1.fi>
2017-03-04 17:30:10 +02:00
Jouni Malinen
12a81b64e1 ACS: Remove unreachable case from a debug print
n_chans can have only values 1, 2, or 4 in this function, so the -1 case
could never be reached. Remove the unreachable case to get rid of static
analyzer warnings.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
2016-01-07 16:50:53 +02:00
Jouni Malinen
a95cc47a92 ACS: Be more consistent with iface->current_mode checks
Offloading of ACS to the driver changed the design a bit in a way that
iface->current_mode could actually be NULL when the offloaded ACS
mechanism supports band selection in addition to channel selection. This
resulted in a combination that is too complex for static analyzers to
notice. While acs_init() can be called with iface->current_mode == NULL
that is only in the case where WPA_DRIVER_FLAGS_ACS_OFFLOAD is in use.
In other words, the actual ACS functions like acs_cleanup() that would
dereference iface->current_mode are not used in such a case.

Get rid of static analyzer warnings by explicitly checking
iface->current_mode in acs_init() for the case where ACS offloading is
not used.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
2016-01-07 16:39:10 +02:00
Srinivasa Duvvuri
567098ec74 ACS: Scan only channels specified in the channel list
The ACS code part of hostapd scans all the channels even if the channel
list is specified in the hostapd.conf. Limit the ACS scan channels to
the list specified in the config file.

Signed-off-by: Srinivasa Duvvuri<sduvvuri@chromium.org>
2015-05-24 10:38:27 +03:00
Manikandan Mohan
857d94225a Extend offloaded ACS QCA vendor command to support VHT
Update ACS driver offload feature for VHT configuration. In addition,
this allows the chanlist parameter to be used to specify which channels
are included as options for the offloaded ACS case.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
2015-03-23 12:18:05 +02:00
Jouni Malinen
0d7eb4344f ACS: Accept channel if any (rather than all) survey results are valid
Previously, a channel with even a single scan/survey result missing
information was skipped in ACS. This may not be desirable in cases when
multiple scan iterations are used (which is the case by default in
hostapd). Instead, use all channels that provided at least one complete
set of results. Calculate the average interference factor as an average
of the iterations that did provide complete values.

This seems to help with some cases, e.g., when ath9k may not be able to
report the noise floor for all channels from the first scan iteration
immediately after the driver has been loaded, but then returns it for
all other scan iterations.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
2015-02-06 21:26:32 +02:00
Jouni Malinen
68fa00c341 ACS: Allow specific channels to be preferred
The new acs_chan_bias configuration parameter is a space-separated list
of <channel>:<bias> pairs. It can be used to increase (or decrease) the
likelihood of a specific channel to be selected by the ACS algorithm.
The total interference factor for each channel gets multiplied by the
specified bias value before finding the channel with the lowest value.
In other words, values between 0.0 and 1.0 can be used to make a channel
more likely to be picked while values larger than 1.0 make the specified
channel less likely to be picked. This can be used, e.g., to prefer the
commonly used 2.4 GHz band channels 1, 6, and 11 (which is the default
behavior on 2.4 GHz band if no acs_chan_bias parameter is specified).

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
2015-02-06 17:59:57 +02:00
Jouni Malinen
6f41a25805 ACS: Use weighted average for 2.4 GHz adjacent channel interference
The interference factors for adjacent 2.4 GHz channels were summed
together without doing any kind of weighted average on them. This
resulted in the channels at the band edges getting undue preference due
to only including interference factors from three channels vs. five for
the channels in the middle of the band.

While it is somewhat unclear whether the design here was supposed to
count overlapping channels together in this way or whether that is
already covered in channel survey results, it is clear that this summing
of three to five values together and then comparing the sum rather than
average of some kind gives too much preference to the channels at the
edges of the band by assuming that there is no interference whatsoever
outside the band.

Use weighted average of the interference factors rather than a sum from
different number of values. For now, the adjacent 2.4 GHz channels get
weight of 0.85 (1.0 for the main channel itself) and the neighboring
channels to those adjacent ones get 0.55 weight. Band-edge channels are
handled in a way that takes average over the channels that were actually
considered instead of assuming zero interference from neighboring bands.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
2015-02-06 17:21:17 +02:00
Adrien Decostre
1648cc6427 ACS: Allow subset of channels to be configured
Add the possibility to define a subset of channels used by the ACS
engine when not operating on DFS channels.

Signed-off-by: Adrien Decostre <ad.decostre@gmail.com>
2015-01-19 02:35:43 +02:00
Peng Xu
16689c7cfc hostapd: Allow ACS to be offloaded to the driver
Using QCA vendor command, allow ACS function to be offloaded to the
driver. Once channels are selected, hostapd is notified to perform OBSS
operation.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
2014-12-03 22:31:53 +02:00
Jouni Malinen
4d1e38be9e ACS: Fix number of error path issues
Especially when multiple BSSes are used with ACS, number of the error
paths were not cleaning up driver initialization properly. This could
result in using freed memory and crashing the process if ACS failed.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
2014-03-25 13:12:29 +02:00
Michal Kazior
c3722e1241 ACS: Fix VHT20
The center segment0 calculation for VHT20 ACS was incorrect. This caused
ACS to fail with: "Could not set channel for kernel driver".

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
2014-03-15 19:04:31 +02:00
Pawel Kulakowski
185677b74c Disable interface if ACS fails
In case of Automatic Channel Selection (ACS) failure, we do not have a
real fallback path. Interface still remains in ACS state. To reflect we
did not succeed with ACS, simply disable the interface and indicate this
to user/upper layer entity so that a suitable recovery or error
notification can be performed.

Signed-off-by: Pawel Kulakowski <pawel.kulakowski@tieto.com>
2014-03-06 23:12:33 +02:00
Michal Kazior
89de64c5c0 ACS: Fix VHT80 segment picking
For example, the previous implementation considered [44, 48, 52, 56] to
be a valid VHT80 channel -- which it is not. This resulted in, e.g.,
failure to start CAC when channels on overlapped segments included DFS
channels.

Add a check similar to the HT40 one to prevent that. The check is
performed this way as the ACS implementation assumes the primary channel
to be the first channel in a given segment.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
2014-03-06 00:01:29 +02:00
Jouni Malinen
f7fb676633 ACS: Mark acs_fail() static
This function is not used outside acs.c.

Signed-hostap: Jouni Malinen <j@w1.fi>
2013-12-31 22:30:49 +02:00
Jouni Malinen
e1c5faf007 hostapd: Track interface state
The new hostapd_iface::state enum is used to track the current state of
the hostapd interface (a radio/wiphy).

Signed-hostap: Jouni Malinen <j@w1.fi>
2013-11-03 19:51:06 +02:00
Jouni Malinen
ae134e1d2b hostapd: Add ctrl_iface events for ACS
These give status information to external observers from automatic
channel selection operations.

Signed-hostap: Jouni Malinen <j@w1.fi>
2013-11-03 19:51:06 +02:00
Helmut Schaa
770ecdf27c ACS: Do not get stuck while failing to do a subsequent scan
Return control flow to hostapd by calling hostapd_acs_completed()
if requesting a scan from the underlying device fails.

Signed-hostapd: Helmut Schaa <helmut.schaa@googlemail.com>
2013-10-31 15:12:21 +02:00
Jouni Malinen
e7ecab4a3b Use ARRAY_SIZE() macro
Replace the common sizeof(a)/sizeof(a[0]) constructions with a more
readable version.

Signed-hostap: Jouni Malinen <j@w1.fi>
2013-10-26 17:49:05 +03:00
Helmut Schaa
677cf19091 hostapd: Select any supported channel if ACS fails
Signed-hostap: Helmut Schaa <helmut.schaa@googlemail.com>
2013-10-23 00:44:48 +03:00
Helmut Schaa
20f9cb1842 hostapd: Allow ACS to deal with partial survey data
Previously ACS required valid survey data on all available channels.
This can however not be guaranteed. Instead of just failing, fall back
to the subset of channels that have valid ACS data.

Signed-hostap: Helmut Schaa <helmut.schaa@googlemail.com>
2013-10-23 00:44:41 +03:00
Helmut Schaa
3645fd5aae hostapd: Propagate ACS errors to iface setup
Otherwise hostapd might hang doing nothing anymore. Propagate ACS
errors so we can fail gracefully.

Signed-hostap: Helmut Schaa <helmut.schaa@googlemail.com>
2013-10-23 00:44:36 +03:00
Michal Kazior
50f4f2a066 hostapd: Add Automatic Channel Selection (ACS) support
This adds ACS support to hostapd. Currently only survey-based
algorithm is available.

To use ACS you need to enable CONFIG_ACS=y in .config and use
channel=0 (or channel=acs_survey) in hostapd.conf.

For more details see wiki page [1] or comments in src/ap/acs.c.

[1]: http://wireless.kernel.org/en/users/Documentation/acs

Signed-hostap: Michal Kazior <michal.kazior@tieto.com>
2013-08-31 11:51:06 +03:00