Commit graph

601 commits

Author SHA1 Message Date
Arowa Suliman
b829b7003a wpa_supplicant: Notify freq change on CH_SWITCH
wpa_supplicant does not send a D-Bus notification of the BSS frequency
change when a CSA happens. Sending a PropertyChanged signal with the
updated frequency will notify the network manager quickly, instead of
waiting for the next scan results.

Signed-off-by: Arowa Suliman <arowa@chromium.org>
Reviewed-by: Brian Norris <briannorris@chromium.org>
2021-02-06 16:50:19 +02:00
David Su
11355a122d Reset external_scan_running on interface deletion
Currently, the external_scan_running flag is not reset when an interface
is removed. Thus, if a connection attempt is made on another iface, it
will fail due to wpa_supplicant incorrectly assuming the radio is still
busy due to the ongoing scan.

To fix this, convert external_scan_running to a pointer to the interface
that started the scan. If this interface is removed, also reset the
pointer to NULL so that other operations may continue on this radio.

Test:
  1. Start scan on wlan0
  2. Remove wlan0
  3. Can connect to a network on wlan1

Signed-off-by: David Su <dysu@google.com>
2021-02-02 23:48:14 +02:00
Ilan Peer
363768c8ac PASN: Add support for PASN processing to wpa_supplicant
Add PASN implementation to wpa_supplicant

1. Add functions to initialize and clear PASN data.
2. Add functions to construct PASN Authentication frames.
3. Add function to process PASN Authentication frame.
4. Add function to handle PASN frame TX status.
5. Implement the station side flow processing for PASN.

The implementation is missing support for wrapped data and PMKSA
establishment for base AKMs, and only supports PASN authentication or
base AKM with PMKSA caching.

The missing parts will be added in later patches.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
2021-01-25 19:15:44 +02:00
Ilan Peer
d70060f966 WPA: Add PTKSA cache to wpa_supplicant for PASN
PASN requires to store the PTK derived during PASN authentication
so it can later be used for secure LTF etc. This is also true
for a PTK derived during regular connection.

Add an instance of a PTKSA cache for each wpa_supplicant
interface when PASN is enabled in build configuration.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
2021-01-25 18:36:40 +02:00
Sunil Dutt
f39d6aacbb P2P: Recover p2p_find operation in case of failure to fetch scan results
Add a handler to notify failures to fetch the scan results and provide
an option to override default behavior of requesting a new scan in one
second in such an error condition. Use this new handler mechanism to
continue the p2p_find operation (by invoking p2p_scan_res_handled) for
an interim scenario where the p2p_scan attempt fails to get the scan
results from the driver which can happen, e.g., if there are parallel
updates to the cfg80211 scan results.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-12-21 23:04:54 +02:00
Vamsi Krishna
084b3d2f8a Drop unexpected connection event while disconnected
If there is a disconnect command from wpa_supplicant immediately after
the driver sends a connection event to userspace but before that event
is received and processed by wpa_supplicant, wpa_supplicant processes
the disconnect command and a self-generated disconnected event first
followed by the connected event received from the driver. As a result
wpa_supplicant moves to the WPA_COMPLETED state.  Whereas the driver
processes the disconnect command received from wpa_supplicant after it
sends the connected event and moves to the disconnected state. Due to
this race between the disconnect command from wpa_supplicant and the
connected event from the driver, wpa_supplicant is moving to the
connected state though the driver is moving to the disconnected state
which results in abnormal functionality.

Ignore the connection event coming from the driver when wpa_supplicant
is not trying to connect after a disconnect command is issued but before
the next connect command is issued to fix the above mentioned race
condition.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-12-21 14:06:52 +02:00
Jouni Malinen
be7ee264f6 BSS: Use wrapper function for getting a pointer to the IE buffer
This makes it easier to change the internal struct wpa_bss design for
storing the variable length IE buffers.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-11-16 16:21:56 +02:00
Vinita S. Maloo
60c902f408 Add connect fail reason code from the driver to assoc reject event
Add support to report a vendor specific connect fail reason code fetched
from the driver to users by adding the reason code to the event
CTRL-EVENT-ASSOC-REJECT. Fetch the connect fail reason code when the
driver sends a failure connection result and append the reason code, if
available, to assoc reject event.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-11-16 13:15:28 +02:00
Kevin Lund
d530110028 wpa_supplicant: Implement time-based blacklisting
wpa_supplicant keeps a blacklist of BSSs in order to prevent repeated
associations to problematic APs*. Currently, this blacklist is
completely cleared whenever we successfully connect to any AP. This
causes problematic behavior when in the presence of both a bad AP and
a good AP. The device can repeatedly attempt to roam to the bad AP
because it is clearing the blacklist every time it connects to the good
AP. This results in the connection constantly ping-ponging between the
APs, leaving the user stuck without connection.

Instead of clearing the blacklist, implement timeout functionality which
allows association attempts to blacklisted APs after some time has
passed. Each time a BSS would be added to the blacklist, increase the
duration of this timeout exponentially, up to a cap of 1800 seconds.
This means that the device will no longer be able to immediately attempt
to roam back to a bad AP whenever it successfully connects to any other
AP.

Other details:
The algorithm for building up the blacklist count and timeout duration
on a given AP has been designed to be minimally obtrusive. Starting with
a fresh blacklist, the device may attempt to connect to a problematic AP
no more than 6 times in any ~45 minute period. Once an AP has reached a
blacklist count >= 6, the device may attempt to connect to it no more
than once every 30 minutes. The goal of these limits is to find an
ideal balance between minimizing connection attempts to bad APs while
still trying them out occasionally to see if the problems have stopped.

The only exception to the above limits is that the blacklist is still
completely cleared whenever there are no APs available in a scan. This
means that if all nearby APs have been blacklisted, all APs will be
completely exonerated regardless of their blacklist counts or how close
their blacklist entries are to expiring. When all nearby APs have been
blacklisted we know that every nearby AP is in some way problematic.
Once we know that every AP is causing problems, it doesn't really make
sense to sort them beyond that because the blacklist count and timeout
duration don't necessarily reflect the degree to which an AP is
problematic (i.e. they can be manipulated by external factors such as
the user physically moving around). Instead, its best to restart the
blacklist and let the normal roaming algorithm take over to maximize
our chance of getting the best possible connection quality.

As stated above, the time-based blacklisting algorithm is designed to
be minimally obtrusive to user experience, so occasionally restarting
the process is not too impactful on the user.

*problematic AP: rejects new clients, frequently de-auths clients, very
poor connection quality, etc.

Signed-off-by: Kevin Lund <kglund@google.com>
Signed-off-by: Brian Norris <briannorris@chromium.org>
2020-10-10 18:34:59 +03:00
Roy Marples
e8b85c078e iface match: Unspecified matched interfaces should not log driver fails
If there is no matching interface given, but interface matching is
enabled, all interfaces on the system will try to be initialized. Non
wireless interfaces will fail and the loopback device will be one of
these, so just log a diagnostic rather than an error.

Signed-off-by: Roy Marples <roy@marples.name>
2020-10-09 16:50:36 +03:00
Jouni Malinen
90e478aa0a DPP2: Use the PFS fallback if multiple key_mgmt values are enabled
Previously this fallback from PFS enabled to disabled (and back to
enabled) was used only if the local network profile used key_mgmt=DPP,
i.e., did not enable another other AKM. That leaves out some valid cases
since the local network profile could actually enable both DPP and SAE.
Extend this check to accept cases DPP AKM is enabled and it was selected
for the connection even if there other enabled AKMs.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-09-23 23:06:55 +03:00
Vinita S. Maloo
af8ab3208d MSCS: Parse result of MSCS setup in (Re)Association Response frames
Add support to parse the (Re)Association Response frames to check if the
AP has accepted/declined the MSCS request in response to the
corresponding (Re)Association Request frame. AP indicates the result by
setting it in the optional MSCS Status subelement of MSCS Descriptor
element in (Re)Association Response frame.

This MSCS Status subelement is defined in the process of being added
into P802.11-REVmd/D4.0 (11-20-0516-17-000m-cr-mscs-and-cid4158).

Signed-off-by: Vinita S. Maloo <vmaloo@codeaurora.org>
2020-08-14 11:53:37 +03:00
Vinita S. Maloo
bbd3178af4 MSCS: Add support to process MSCS Response frames
Add support to receive and process MSCS Response frames from the AP and
indicate the status to upper layers.

Signed-off-by: Vinita S. Maloo <vmaloo@codeaurora.org>
2020-08-14 11:53:37 +03:00
Veerendranath Jakkam
596d99567a SME: Process channel switch event in SME only when supplicant's SME is used
Do not process channel switch event in wpa_supplicant's SME when SME is
offloaded to the driver/firmware to avoid SA Query initiation from both
wpa_supplicant and the driver/firmware for the OCV case.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-08-13 21:39:49 +03:00
Veerendranath Jakkam
dbe485a35a SAE-PK: Check psk param also to look for SAE-PK acceptable BSS
SAE-PK password can be set using psk parameter also in case of mixed
SAE+PSK networks, so look for acceptable SAE-PK BSS when SAE password
not set and psk parameter meets SAE-PK password criteria.

Signed-off-by: Veerendranath Jakkam <vjakkam@codeaurora.org>
2020-08-13 17:31:38 +03:00
Matthew Wang
b97aa038b7 Add WPA_EVENT_{DO,SKIP}_ROAM events
Add events for within-ESS reassociation. This allows us to monitor roam
events, both skipped and allowed, in tests.

Signed-off-by: Matthew Wang <matthewmwang@chromium.org>
2020-06-19 18:34:26 +03:00
Matthew Wang
d6b450e890 Refactor wpa_supplicant_need_to_roam()
Pull all the within-ESS roam code out of wpa_supplicant_need_to_roam()
and into its own function, wpa_supplicant_need_to_roam_within_ess().
This way, we avoid interleaving several #ifndef's in the original
function and wrap the new function in one big #ifndef. This also
modularizes the within-ESS roam code and makes it easier to test.

Signed-off-by: Matthew Wang <matthewmwang@chromium.org>
2020-06-19 18:30:08 +03:00
Jouni Malinen
fcef598ea2 Do not try to connect with zero-length SSID
It was possible to find a BSS to local network profile match for a BSS
entry that has no known SSID when going through some of the SSID
wildcard cases. At leas the OWE transition mode case without BSSID match
could result in hitting this. Zero-length SSID (i.e., wildcard SSID) is
not valid in (Re)Association Request frame, so such an association will
fail. Skip such a BSS to avoid known-to-be-failing association attempts.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-06-08 21:40:56 +03:00
Jouni Malinen
5f48d36b4a SAE-PK: Select SAE-PK network over SAE without PK
If there is an acceptable BSS with SAE-PK enabled in the same ESS,
select that over a BSS that does not enable SAE-PK when the network
profile uses automatic SAE-PK selection.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-06-07 16:49:07 +03:00
Jouni Malinen
d654ca24de Clean up wpa_scan_res_match()
Move the BSS-against-SSID matching into a separate helper function to
make this overly long function a bit more readable and to allow that
helper function to be used for other purposes.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-06-07 16:30:32 +03:00
Jouni Malinen
9ad010c290 SAE-PK: Allow automatic SAE-PK to be disabled
This replaces the previously used sae_pk_only configuration parameter
with a more generic sae_pk that can be used to specify how SAE-PK is
negotiated. The default behavior (sae_pk=0) is to automatically
negotiate SAE-PK whenever the AP supports it and the password is in
appropriate format. sae_pk=1 allows only SAE-PK to be used and sae_pk=2
disables SAE-PK completely.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-06-07 11:55:16 +03:00
Jouni Malinen
1c846d647e SAE-PK: Allow SAE authentication without PK to be disabled
The new wpa_supplicant network profile parameter sae_pk_only=1 can now
be used to disable use of SAE authentication without SAE-PK.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-06-06 15:18:13 +03:00
Jouni Malinen
c2080e8657 Clear current PMKSA cache selection on association/roam
It was possible for the RSN state machine to maintain old PMKSA cache
selection (sm->cur_pmksa) when roaming to another BSS based on
driver-based roaming indication. This could result in mismatching state
and unexpected behavior, e.g., with not generating a Suite B PMKSA cache
entry.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-05-25 16:25:50 +03:00
Jouni Malinen
0a488ef35c DPP: Track ending time for remain-on-channel operations
This may be needed to optimize use of offchannel TX operations with
wait-for-response when near the end of a pending remain-on-channel
operation.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-05-09 17:32:26 +03:00
Jouni Malinen
12c8eacf73 DPP: Allow version number to be overridden for testing purposes
"SET dpp_version_override <ver>" can now be used to request
wpa_supplicant and hostapd to support a subset of DPP versions. In
practice, the only valid case for now is to fall back from DPP version 2
support to version 1 in builds that include CONFIG_DPP2=y.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-05-04 00:37:45 +03:00
Jouni Malinen
da8478a1ab EAPOL supp: Convert Boolean to C99 bool
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-04-24 17:06:50 +03:00
Jouni Malinen
0e794989e5 Beacon frame protection event for incorrect protection
Define a driver interface event for Beacon frame protection failures.
Report such events over the control interface and send a
WNM-Notification Request frame to the AP as well.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-04-01 16:22:48 +03:00
Jouni Malinen
5058f771d9 DPP2: Allow station to require or not allow PFS
The new wpa_supplicant network profile parameter dpp_pfs can be used to
specify how PFS is applied to associations. The default behavior
(dpp_pfs=0) remains same as it was previously, i.e., try to use PFS if
the AP supports it. PFS use can now be required (dpp_pfs=1) or disabled
(dpp_pfs=2).

This is also working around an interoperability issue of DPP R2 STA with
certain hostapd builds that included both OWE and DPP functionality.
That issue was introduced by commit 09368515d1 ("OWE: Process
Diffie-Hellman Parameter element in AP mode") and removed by commit
16a4e931f0 ("OWE: Allow Diffie-Hellman Parameter element to be
included with DPP"). hostapd builds between those two commits would
reject DPP association attempt with PFS. The new wpa_supplicant default
(dpp_pfs=0) behavior is to automatically try to connect again with PFS
disabled if that happens.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-03-28 17:23:22 +02:00
Jouni Malinen
d2d16e3100 Use size_t instead of int or unsigned int for configuration items
While int and unsigned int are not going overflow in practice as 32-bit
values, these could at least in theory hit an integer overflow with
16-bit int. Use size_t to avoid such potential issue cases.

Signed-off-by: Jouni Malinen <j@w1.fi>
2020-03-22 18:50:04 +02:00
Jouni Malinen
fab94f16e6 Indicate scan completion in active AP mode even when ignoring results
This is needed to avoid leaving external components (through control
interface or D-Bus) timing out while waiting for the scan completion
events. This was already taken care of for the scan-only case
("TYPE=only"), but the scan-and-allow-roaming case did not report the
scan completion event when operating in AP mode.

Signed-off-by: Jouni Malinen <j@w1.fi>
2020-03-15 21:18:16 +02:00
Jouni Malinen
f21fbfb977 Allow RSNE in EAPOL-Key msg 2/4 to be overridden for testing purposes
The new wpa_supplicant control interface parameter rsne_override_eapol
can be used similarly to the earlier rsnxe_override_eapol to override
the RSNE value added into EAPOL-Key msg 2/4.

Signed-off-by: Jouni Malinen <j@w1.fi>
2020-03-15 11:11:38 +02:00
Gurumoorthi Gnanasambandhan
1d9cff86bd Multi-AP: Set 4-address mode after network selection
Split multi_ap_process_assoc_resp() to set 4-address mode after network
selection. Previously, wpa_s->current_ssid might have been NULL in some
cases and that would have resulted in 4-address mode not getting enabled
properly.

Signed-off-by: Gurumoorthi Gnanasambandhan <gguru@codeaurora.org>
2020-03-13 17:00:19 +02:00
Jouni Malinen
3c73811507 OWE: Mark BSS for transition mode based on active OWE network profiles
It is possible for the hidden OWE BSS to be found based on SSID-specific
scan (e.g., from the special OWE scan mechanism). In that sequence, the
previously used learning of OWE BSS was skipped since the SSID was
already present in the BSS entry. This could result in not being able to
find a matching BSS entry for the OWE BSS in transition mode.

Fix this by adding the BSS flag for transition mode based on SSID
matching against currently enabled OWE network profiles in addition to
the previous mechanism.

Signed-off-by: Jouni Malinen <j@w1.fi>
2020-03-08 16:16:11 +02:00
Jouni Malinen
ecb5219d8c OWE: Avoid incorrect profile update in transition mode
The "unexpected" change of SSID between the current network profile
(which uses the SSID from the open BSS in OWE transition mode) and the
association with the OWE BSS (which uses a random, hidden SSID) resulted
in wpa_supplicant incorrectly determining that this was a
driver-initiated BSS selection ("Driver-initiated BSS selection changed
the SSID to <the random SSID from OWE BSS>" in debug log).

This ended up with updating security parameters based on the network
profile inwpa_supplicant_set_suites() instead of using the already
discovered information from scan results. In particular, this cleared
the RSN supplicant state machine information of AP RSNE and resulted in
having to fetch the scan results for the current BSS when processing
EAPOL-Key msg 3/4.

Fix this by recognizing the special case for OWE transition mode where
the SSID for the associated AP does not actually match the SSID in the
network profile.

Signed-off-by: Jouni Malinen <j@w1.fi>
2020-03-07 18:03:32 +02:00
Jouni Malinen
200c7693c9 Make WEP functionality an optional build parameter
WEP should not be used for anything anymore. As a step towards removing
it completely, move all WEP related functionality to be within
CONFIG_WEP blocks. This will be included in builds only if CONFIG_WEP=y
is explicitly set in build configuration.

Signed-off-by: Jouni Malinen <j@w1.fi>
2020-02-29 17:45:25 +02:00
Alexander Wetzel
1f90a49d02 STA: Allow PTK rekeying without Ext KeyID to be disabled as a workaround
Rekeying a pairwise key using only keyid 0 (PTK0 rekey) has many broken
implementations and should be avoided when using or interacting with
one. The effects can be triggered by either end of the connection and
range from hardly noticeable disconnects over long connection freezes up
to leaking clear text MPDUs.

To allow affected users to mitigate the issues, add a new configuration
option "wpa_deny_ptk0_rekey" to replace all PTK0 rekeys with fast
reconnects.

Signed-off-by: Alexander Wetzel <alexander@wetzel-home.de>
2020-02-23 13:05:19 +02:00
Veerendranath Jakkam
adf3de44ca Add check to consider band in enabling connection_vht flag
connection_vht flag was set to true when both Association Request and
Response frame IEs have VHT capability. Thus all devices that have
support for the vendor specific partial VHT support in the 2.4 GHz band
were also being reported as VHT capable. However, IEEE Std 802.11ac-2013
defines VHT STA to operate in frequency bands below 6 GHz excluding the
2.4 GHz band.

Do not set connection_vht when the operating band is 2.4 GHz. This
avoids reporting wifi_generation 5 on the 2.4 GHz band and reserves the
generation value 5 for full VHT as defined in the IEEE 802.11 standard.

Signed-off-by: Veerendranath Jakkam <vjakkam@codeaurora.org>
2020-02-11 05:19:16 +02:00
Jouni Malinen
641d79f165 SAE: Special test mode sae_pwe=3 for looping with password identifier
The new sae_pwe=3 mode can be used to test non-compliant behavior with
SAE Password Identifiers. This can be used to force use of
hunting-and-pecking loop for PWE derivation when Password Identifier is
used. This is not allowed by the standard and as such, this
functionality is aimed at compliance testing.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-02-10 05:13:13 +02:00
Jouni Malinen
e36a5894d0 SAE: Use H2E whenever Password Identifier is used
IEEE P802.11-REVmd was modified to require H2E to be used whenever
Password Identifier is used with SAE.

See this document for more details of the approved changes:
https://mentor.ieee.org/802.11/dcn/19/11-19-2154-02-000m-sae-anti-clogging-token.docx

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-01-21 13:13:56 +02:00
Jouni Malinen
29dd0b3164 SAE H2E: Check H2E-only BSS membership selector only if SAE is enabled
This BSS membership selector has impact only for SAE functionality, so
ignore it when configured not to use SAE. This allows WPA-PSK connection
to and AP that advertises WPA-PSK and SAE while requiring H2E for SAE.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-01-20 21:17:28 +02:00
Jouni Malinen
dd530b8739 Silence compiler warning with CONFIG_NO_ROAMING=y
Comment out unused static functions if CONFIG_NO_ROAMING is defined.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-01-09 12:40:17 +02:00
Vamsi Krishna
33c8a10498 Do not select APs found on disabled channels for connection
If a channel list changed event is received after a scan and before
selecting a BSS for connection, a BSS found on a now disabled channel
may get selected for connection. The connect request issued with the BSS
found on a disabled channel is rejected by cfg80211. Filter out the BSSs
found on disabled channels and select from the other BSSs found on
enabled channels to avoid unnecessary connection attempts that are bound
to fail.

The channel list information will be updated by the driver in cases like
country code update, disabling/enabling specific bands, etc. which can
occur between the scan and connection attempt.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
2020-01-08 16:19:47 +02:00
Jouni Malinen
c8eb7fe66c Fix signal_poll based roaming skip
Fix a rebasing issue in the signal difference calculation. The older
patch was not updated to use the new cur_level local variable to get the
possibly updated signal level for the current BSS.

Fixes: a2c1bebd43 ("Improve roaming logic")
Signed-off-by: Jouni Malinen <j@w1.fi>
2020-01-02 20:34:39 +02:00
Jouni Malinen
ad2f096609 Maintain BSS entries for 5 seconds after interface is disabled
This is targeting the case of MAC address change for an association
which may require the interface to be set down for a short moment.
Previously, this ended up flushing the BSS table that wpa_supplicant
maintained and that resulted in having to scan again if the MAC address
was changed between the previous scan and the connection attempt. This
is unnecessary extra latency, so maintain the BSS entries for 5 seconds
(i.e., the same time that the old scan results are consider valid for a
new connection attempt) after an interface goes down.

Signed-off-by: Jouni Malinen <j@w1.fi>
2020-01-02 12:58:58 +02:00
Jouni Malinen
988f14448a Indicated if the selected BSS is the current BSS
This makes scan result processing a bit more readable in debug log.

Signed-off-by: Jouni Malinen <j@w1.fi>
2020-01-01 17:55:26 +02:00
Jouni Malinen
a8ad9c31db Make min_diff determination from cur_level more readable
This handles both the dBm and unspecified unit cases.

Signed-off-by: Jouni Malinen <j@w1.fi>
2020-01-01 17:46:03 +02:00
Jouni Malinen
41f72d7356 Use sel_est consistently with cur_sel in wpa_supplicant_need_to_roam()
This makes the code a bit easier to read.

Signed-off-by: Jouni Malinen <j@w1.fi>
2020-01-01 17:37:58 +02:00
Matthew Wang
a2c1bebd43 Improve roaming logic
Currently, wpa_supplicant may roam too aggressively; the need_to_roam()
function will return early with a roaming decision if the difference in
signal level or throughput between the current and selected APs is
"sufficiently large." In particular, if the selected AP's estimated
throughput is more than 5k greater than the current AP's estimated
throughput, wpa_supplicant will decide to roam. Otherwise, if the
selected AP's signal level is less than the current AP's signal level,
or the selected AP's estimated throughput is at least 5k less than the
current AP's estimated throughput, wpa_supplicant will skip the roam.
These decisions are based only on one factor and can lead to poor
roaming choices (e.g., a roam should not happen if the selected AP's
estimated throughput meets the threshold but the current signal and
throughput are already good, whereas a roam should happen if the signal
is slightly worse but the estimated throughput is significantly better).

This change standardizes the roaming heuristic for signal strength
difference requirements and will hopefully improve user experience. The
change can be summarized as follows: based on the current signal level,
a certain roaming difficulty is assigned. Based on the selected AP's
estimated throughput relative to the current AP's estimated throughput,
the difficulty is adjusted up or down. If the difference in signal level
meets the threshold, a roam happens.

The hard-coded values were selected purely based on the previous version
of this function. They may eventually need to be fine-tuned for optimal
performance.

Signed-off-by: Matthew Wang <matthewmwang@chromium.org>
2020-01-01 17:33:51 +02:00
Jouni Malinen
9c8d550b77 Allow roam to lower signal level if throughput benefit is significant
Do not prevent roam to a different BSS based only on the signal level
with the current BSS being higher than with the selected BSS. If the
estimated throughput is significantly higher (> 20%), allow roaming if
the following conditions are met.

Signed-off-by: Jouni Malinen <j@w1.fi>
2020-01-01 17:09:18 +02:00
Jouni Malinen
9fafefb9e5 Skip roaming based on signal level difference if current SNR is good
If the current SNR with the associated BSS is sufficiently good (better
than GREAT_SNR = 25), there is limited benefit from moving to another
BSS even if that BSS were to have a higher signal level. As such, skip
roaming based on the signal level difference between the selected BSS
from scan results and the current BSS for such cases.

Signed-off-by: Jouni Malinen <j@w1.fi>
2020-01-01 16:56:40 +02:00