These events are sent if IWD fails to authentiate
(ft-over-air-roam-failed) or if it falls back to over air after
failing to use FT-over-DS (try-ft-over-air)
If IPv4 setup fails and the netconfig logic gives up, continue as if the
connection had failed at earlier stages so that autoconnect can try the
next available network.
Certain drivers support/require probe response offloading which
IWD did not check for or properly handle. If probe response
offloading is required the probe response frame watch will not
be added and instead the ATTR_PROBE_RESP will be included with
START_AP.
The head/tail builders were reused but slightly modified to check
if the probe request frame is NULL, since it will be for use with
START_AP.
Parse the AP probe response offload attribute during the dump. If
set this indicates the driver expects the probe response attribute
to be included with START_AP.
Clearing all authentications during ft_authenticate was a very large
hammer and may remove cached authentications that could be used if
the current auth attempt fails.
For example the best BSS may have a problem and fail to authenticate
early with FT-over-DS, then fail with FT-over-Air. But another BSS
may have succeeded early with FT-over-DS. If ft_authenticate clears
all ft_infos that successful authentication will be lost.
AP roaming was structured such that any AP roam request would
force IWD to roam (assuming BSS's were found in scan results).
This isn't always the best behavior since IWD may be connected
to the best BSS in range.
Only force a roam if the AP includes one of the 3 disassociation/
termination bits. Otherwise attempt to roam but don't set the
ap_directed_roaming flag which will allows IWD to stay with the
current BSS if no better candidates are found.
There are a few checks that can be done prior to parsing the
request, in addition the explicit check for preparing_roam was
removed since this is taken care of by station_cannot_roam().
Once offchannel completes we can check if the info structure was
parsed, indicating authentication succeeded. If not there is no
reason to keep it around since IWD will either try another BSS or
fail.
This both adds proper handling to the new roaming logic and fixes
a potential bug with firmware roams.
The new way roaming works doesn't use a connect callback. This
means that any disconnect event or call to netdev_connect_failed
will result in the event handler being called, where before the
connect callback would. This means we need to handle the ROAMING
state in the station disconnect event so IWD properly disassociates
and station goes out of ROAMING.
With firmware roams netdev gets an event which transitions station
into ROAMING. Then netdev issues GET_SCAN. During this time a
disconnect event could come in which would end up in
station_disconnect_event since there is no connect callback. This
needs to be handled the same and let IWD transition out of the
ROAMING state.
This finalizes the refactor by moving all the handshake prep
into FT itself (most was already in there). The netdev-specific
flags and state were added into netdev_ft_tx_associate which
now avoids any need for a netdev API related to FT.
The NETDEV_EVENT_FT_ROAMED event is now emitted once FT completes
(netdev_connect_ok). This did require moving the 'in_ft' flag
setting until after the keys are set into the kernel otherwise
netdev_connect_ok has no context as to if this was FT or some
other connection attempt.
In addition the prev_snonce was removed from netdev. Restoring
the snonce has no value once association begins. If association
fails it will result in a disconnect regardless which requires
a new snonce to be generated
This converts station to using ft_action/ft_authenticate and
ft_associate and dropping the use of the netdev-only/auth-proto
logic.
Doing this allows for more flexibility if FT fails by letting
IWD try another roam candidate instead of disconnecting.
Now the full action frame including the header is provided to ft
which breaks the existing parser since it assumes the buffer starts
at the body of the message.
This forwards Action, Authentication and Association frames to
ft.c via their new hooks in netdev.
Note that this will break FT-over-Air temporarily since the
auth-proto still is in use.
The current behavior is to only find the best roam candidate, which
generally is fine. But if for whatever reason IWD fails to roam it
would be nice having a few backup BSS's rather than having to
re-scan, or worse disassociate and reconnect entirely.
This patch doesn't change the roam behavior, just prepares for
using a roam candidate list. One difference though is any roam
candidates are added to station->bss_list, rather than just the
best BSS. This shouldn't effect any external behavior.
The candidate list is built based on scan_bss rank. First we establish
a base rank, the rank of the current BSS (or zero if AP roaming). Any
BSS in the results with a higher rank, excluding the current BSS, will
be added to the sorted station->roam_bss_list (as a new 'roam_bss'
entry) as well as stations overall BSS list. If the resulting list is
empty there were no better BSS's, otherwise station can now try to roam
starting with the best candidate (head of the roam list).
A new API was added, ft_authenticate, which will send an
authentication frame offchannel via CMD_FRAME. This bypasses
the kernel's authentication state allowing multiple auth
attempts to take place without disconnecting.
Currently netdev handles caching FT auth information and uses FT
parsers/auth-proto to manage the protocol. This sets up to remove
this state machine from netdev and isolate it into ft.c.
This does not break the existing auth-proto (hence the slight
modifications, which will be removed soon).
Eventually the auth-proto will be removed from FT entirely, replaced
just by an FT state machine, similar to how EAPoL works (netdev hooks
to TX/RX frames).
There may be situations (due to Multi-BSS operation) where an AP might
be advertising multiple SSIDs on the same BSSID. It is thus more
correct to lookup the preauthentication target on the network object
instead of the station bss_list. It used to be that the network list of
bsses was not updated when roam scan was performed. Hence the lookup
was always performed on the station bss_list. But this is no longer the
case, so it is safer to lookup on the network object directly on the
network.
The warnings in the authenticate and connect events were identical
so it could be difficult knowing which print it was if IWD is not
in debug mode (to see more context). The prints were changed to
indicate which event it was and for the connect event the reason
attribute is also parsed.
Note the resp_ies_len is also initialized to zero now. After making
the changes gcc was throwing a warning.
FT is special in that it really should not be interrupted. Since
FRAME/OFFCHANNEL have the highest priority we run the risk of
DPP or some other offchannel operation interfering with FT.
FT is now driven (mostly) by station which removes the connect
callback. Instead once FT is completed, keys set, etc. netdev
will send an event to notify station.
Since l_netconfig's DHCPv6 client instance no longer sets parameters on
the l_icmp6_client instance, call l_icmp6_client_set_nodelay() and
l_icmp6_client_set_debug() directly. Also enable optimistic DAD to
speed up IPv6 setup if available.
All uses of frame-xchg were for action frames, and the frame type
was hard coded. Soon other frame types will be needed so the type
must now be specified in the frame_xchg_prefix structure.
This will make the debug API more robust as well as fix issues
certain drivers have when trying to roam. Some of these drivers
may flush scan results after CMD_CONNECT which results in -ENOENT
when trying to roam with CMD_AUTHENTICATE unless you rescan
explicitly.
Now this will be taken care of automatically and station will first
scan for the BSS (or full scan if not already in results) and
attempt to roam once the BSS is seen in a fresh scan.
The logic to replace the old BSS object was factored out into its
own function to be shared by the non-debug roam scan. It was also
simplified to just update the network since this will remove the
old BSS if it exists.
Add a second netconfig-commit backend which, if enabled, doesn't
directly send any of the network configuration to the kernel or system
files but delegates the operation to an interested client's D-Bus
method as described in doc/agent-api.txt. This backend is switched to
when a client registers a netconfig agent object and is swiched away
from when the client disconnects or unregisters the agent. Only one
netconfig agent can be registered any given time.
Add netconfig_event_handler() that responds to events emitted by
the l_netconfig object by calling netconfig_commit, tracking whether
we're connected for either address family and emitting
NETCONFIG_EVENT_CONNECTED or NETCONFIG_EVENT_FAILED as necessary.
NETCONFIG_EVENT_FAILED is a new event as until now failures would cause
the netconfig state machine to stop but no event emitted so that
station.c could take action. As before, these events are only
emitted based on the IPv4 configuration state, not IPv6.
Add netconfig-commit.c whose main method, netconfig_commit actually sets
the configuration obtained by l_netconfig to the system netdev,
specifically it sets local addresses on the interface, adds routes to the
routing table, sets DNS related data and may add entries to the neighbor
cache. netconfig-commit.c uses a backend-ops type structure to allow
for switching backends. In this commit there's only a default backend
that uses l_netconfig_rtnl_apply() and a struct resolve object to write
the configuration.
netconfig_gateway_to_arp is moved from netconfig.c to netconfig-commit.c
(and renamed.) The struct netconfig definition is moved to netconfig.h
so that both files can access the settings stored in the struct.
To avoid repeated lookups by ifindex, replace the ifindex member in
struct netconfig with a struct netdev pointer. A struct netconfig
always lives shorter than the struct netdev.
* make the error handling simpler,
* make error messages more consistent,
* validate address families,
* for IPv4 skip l_rtnl_address_set_noprefixroute()
as l_netconfig will do this internally as needed.
* for IPv6 set the default prefix length to 64 as that's going to be
used for the local prefix route's prefix length and is a more
practical value.
Drop all the struct netconfig members where we were keeping the parsed
netconfig settings and add a struct l_netconfig object. In
netconfig_load_settings load all of the settings once parsed directly
into the l_netconfig object. Only preserve the mdns configuration and
save some boolean values needed to properly handle static configuration
and FILS. Update functions to use the new set of struct netconfig
members.
These booleans mirroring the l_netconfig state could be replaced by
adding l_netconfig getters for settings which currently only have
setters.
In anticipation of switching to use the l_netconfig API, which
internally handles DHCPv4, DHCPv6, ACD, etc., drop pointers to
instances of l_dhcp_client, l_dhcp6_client and l_acd from struct
netconfig. Also drop all code used for handling events from these
APIs, including code to commit the received configurations to the
system. Committing the final settings to the system netdevs is going to
be handled by a new set of utilities in a new file.
