I was aware that this code is not reachable. But for consistency, it
seems better to be explict about it (to avoid future bugs when refactoring).
Anyway, Coverity complains about it. So assert instead.
(cherry picked from commit 643bc4ca22)
When we set the same JSON config twice in a row, the second time has
indeed no effect and we can just return right away (indicating that
no attributes changed).
However, that is not true, if we are in strict validating mode and
the JSON string just happens to be the same. In this case, we still
want to switch from strict validating mode to relaxed mode. Hence,
we should not return early but continue setting the property.
When parsing a NMSettingTeam/NMSettingTeamPort from GVariant, the JSON
"config" is always preferred. If that field is present, all other
attributes are ignored (aside from validating that the individual fields
are as expected).
The idea is that the JSON config anyway must contain everything that artificial
properties could. In this mode, also no validation is performed and the setting is
always accepted (regardless whether libnm thinks the setting verifies).
When a libnm client created the setting via the artificial properties,
only send them via D-Bus and exclude the JSON config. This turns on
strict validation server side.
Now we actually get validation of the settings:
$ nmcli connection add type team team.runner-tx-hash l3
Error: Failed to add 'team' connection: team.runner: runner-tx-hash is only allowed for runners loadbalance,lacp
this is obviously a change in behavior as previously all settings
would have been accepted, regardless whether they made sense.
For each artifical team property we need to track whether it was
explicitly set (i.e., present in JSON/GVariant or set by the user
via NMSettingTeam/NMSettingTeamPort API).
--
As a plus, libnm is now no longer concerned with the underling default values
that teamd uses. For example, the effective default value for "notify_peers.count"
depends on the selected runner. But libnm does not need to care, it only cares
wheher the property is set in JSON or not. This also means that the default (e.g. as
interesting to `nmcli -o con show $PROFILE`) is independent from other properties
(like the runner).
Also change the default value for the GObject properties of
NMSettingTeam and NMSettingTeamPort to indicate the "unset" value.
For most properties, the default value is a special value that is
not a valid configuration itself.
For some properties the default value is itself a valid value, namely,
"runner.active", "runner.fast_rate", "port.sticky" and "port.prio".
As far as NMTeamSetting is concerned, it distinguishes between unset
value and set value (including the default value). That means,
when it parses a JSON or GVariant, it will remember whether the property
was present or not.
When using API of NMSettingTeam/NMSettingTeamPort to set a property to the
default value, it marks the property as unset. For example, setting
NM_SETTING_TEAM_RUNNER_ACTIVE to TRUE (the default), means that the
value will not be serialized to JSON/GVariant. For the above 4
properties (where the default value is itself a valid value) this is a
limitation of libnm API, as it does not allow to explicitly set
'"runner": { "active": true }'. See SET_FIELD_MODE_SET_UNLESS_DEFAULT,
Note that changing the default value for properties of NMSetting is problematic,
because it changes behavior for how settings are parsed from keyfile/GVariant.
For team settings that's not the case, because if a JSON "config" is
present, all other properties are ignore. Also, we serialize properties
to JSON/GVariant depending on whether it's marked as present, and not
whether the value is set to the default (_nm_team_settings_property_to_dbus()).
--
While at it, sticter validate the settings. Note that if a setting is
initialized from JSON, the strict validation is not not performed. That
means, such a setting will always validate, regardless whether the values
in JSON are invalid according to libnm. Only when using the extended
properties, strict validation is turned on.
Note that libnm serializes the properties to GVariant both as JSON "config"
and extended properties. Since when parsing a setting from GVariant will
prefer the "config" (if present), in most cases also validation is
performed.
Likewise, settings plugins (keyfile, ifcfg-rh) only persist the JSON
config to disk. When loading a setting from file, strict validation is
also not performed.
The stricter validation only happens if as last operation one of the
artificial properties was set, or if the setting was created from a
GVariant that has no "config" field.
--
This is a (another) change in behavior.
The order of the fields in the JSON object does not really matter.
Note that with the recent rework the order changed. Before it was
arbitrarily, now it still is arbitrary.
Reorder again, to follow the same order as `man teamd.conf`.
- re-use the existing meta-data. That is, don't duplicate the
dbus-names, the types, or the default value. Instead, parse the
settings according to these flags.
- notice and return if there are any suspicious/wrong keys in the
variant. For strict parsing, we should not silently ignore them.
- previously, the code used g_variant_lookup() to search for the
expected keys. As the number of keys that we look up is fixed, this
still had O(n). But if we want to detect and reject invalid keys,
we cannot use g_variant_lookup() but need to iterate the entire variant
once.
Completely refactor the team/JSON handling in libnm's NMSettingTeam and
NMSettingTeamPort.
- team handling was added as rh#1398925. The goal is to have a more
convenient way to set properties than constructing JSON. This requires
libnm to implement the hard task of parsing JSON (and exposing well-understood
properties) and generating JSON (based on these "artificial" properties).
But not only libnm. In particular nmcli and the D-Bus API must make this
"simpler" API accessible.
- since NMSettingTeam and NMSettingTeamPort are conceptually the same,
add "libnm-core/nm-team-utils.h" and NMTeamSetting that tries to
handle the similar code side-by-sdie.
The setting classes now just delegate for everything to NMTeamSetting.
- Previously, there was a very fuzzy understanding of the provided
JSON config. Tighten that up, when setting a JSON config it
regenerates/parses all other properties and tries to make the
best of it. When modifying any abstraction property, the entire
JSON config gets regenerated. In particular, don't try to merge
existing JSON config with the new fields. If the user uses the
abstraction API, then the entire JSON gets replaced.
For example note that nm_setting_team_add_link_watcher() would not
be reflected in the JSON config (a bug). That only accidentally worked
because client would serializing the changed link watcher to
GVariant/D-Bus, then NetworkManager would set it via g_object_set(),
which would renerate the JSON, and finally persist it to disk. But
as far as libnm is concerned, nm_setting_team_add_link_watcher() would
bring the settings instance in an inconsistent state where JSON and
the link watcher property disagree. Setting any property must
immediately update both the JSON and the abstraction API.
- when constucting a team setting from D-Bus, we would previously parse
both "config" and abstraction properties. That is wrong. Since our
settings plugins only support JSON, all information must be present
in the JSON config anyway. So, when "config" is present, only the JSON
must be parsed. In the best case, the other information is redudant and
contributes nothing. In the worse case, they information differs
(which might happen if the client version differs from the server
version). As the settings plugin only supports JSON, it's wrong to
consider redundant, differing information from D-Bus.
- we now only convert string to JSON or back when needed. Previously,
setting a property resulted in parsing several JSON multiple times
(per property). All operations should now scale well and be reasonably
efficient.
- also the property-changed signals are now handled correctly. Since
NMTeamSetting knows the current state of all attributes, it can emit
the exact property changed signals for what changed.
- we no longer use libjansson to generate the JSON. JSON is supposed
to be a machine readable exchange format, hence a major goal is
to be easily handled by applications. While parsing JSON is not so
trivial, writing a well-known set of values to JSON is.
The advantage is that when you build libnm without libjansson support,
then we still can convert the artificial properties to JSON.
- Requiring libjansson in libnm is a burden, because most of the time
it is not needed (as most users don't create team configurations). With
this change we only require it to parse the team settings (no longer to
write them). It should be reasonably simple to use a more minimalistic
JSON parser that is sufficient for us, so that we can get rid of the
libjansson dependency (for libnm). This also avoids the pain that we have
due to the symbol collision of libjansson and libjson-glib.
https://bugzilla.redhat.com/show_bug.cgi?id=1691619
