LLMNR and mDNS settings can have their global default value configured
in "NetworkManager.conf".
Global default values should work the way that all regular values of the property
can be configured explicitly in the connection profile. The special "default" value
only indicates to allow lookup of the global default, but it should not have a
meaning of its own.
Note that if mDNS/LLMNR settings are left unspecified, we will set the
argument to SetLinkMulticastDNS() and SetLinkLLMNR() functions to "",
which means that systemd-resolved decides on a default. Also, depending
on the DNS plugin, the default value differs. This is all fine however.
In this case, the ultimate default value depends on other things (like
the DNS plugin), but each possible value is in fact explicitly
configurable. We also do that for "ipv6.ip6-privacy".
Anyway, cleanup the documentation a bit and try to better explain what
the default is.
Not being able to compare two NMIPAddress instances is a major
limitation. Add nm_ip_address_cmp_full(). The choice here for adding
a "cmp()" function instead of a "equals()" function is that cmp is
more useful. We only want to add one of the two, so choose the
more powerful one. Yes, usually its also not the variant we want
or the variant that is convenient to use, such is life.
Compare this to:
- nm_ip_route_equal_full(), which is an equal() method and not
a cmp().
- nm_ip_route_equal_full() which has a guint flags argument,
instead of a typedef for an enum, with a proper generated
GType.
- systemd-networkd and initscripts both support it.
- it seems suggested to configure routes with scope "link" on AWS.
- the scope is only supported for IPv4 routes. Kernel ignores the
attribute for IPv6 routes.
- we don't support the aliases like "link" or "global". Instead
only the numeric value is supported. This is different from
systemd-networkd, which accepts names like "global" and "link",
but no numerical values. I think restricting ourself only to
the aliases unnecessarily limits what is possible on netlink.
The alternative would be to allow aliases and numbers both,
but that causes multiple ways to define something and has
thus downsides. So, only numeric values.
- when setting rtm_scope to RT_SCOPE_NOWHERE (0, the default), kernel
will coerce that to RT_SCOPE_LINK. This ambiguity of nowhere vs. link
is a problem, but we don't do anything about it.
- The other problem is, that when deleting a route with scope RT_SCOPE_NOWHERE,
this acts as a wild care and removes the first route that matches (given the
other route attributes). That means, NetworkManager has no meaningful
way to delete a route with scope zero, there is always the danger that
we might delete the wrong route. But this is nothing new to this
patch. The problem existed already previously, except that
NetworkManager could only add routes with scope nowhere (i.e. link).
We will rework NMClient entirely. Then, the synchronous initialization will also use
the asynchronous code paths. The difference will be that with synchronous initialization,
all D-Bus interaction will be done with an internal GMainContext as current thread default,
and that internal context will run until initialization completes.
Note that even after initialization completes, it cannot be swapped back to the user's
(outer) GMainContext. That is because contexts are essentially the queue for our
D-Bus events, and we cannot swap from one queue to the other in a race
free manner (or a full resync). In other words, the two contexts are not in sync,
so after using the internal context NMClient needs to stick to that (at least, until
the name owner gets lost, which gives an opportunity to resync and switch back to the
user's main context).
We thus need to hook the internal (inner) GMainContext with the user's (outer) context,
so when the user iterates the outer context, events on the inner context get dispatched.
Add nm_utils_g_main_context_create_integrate_source() to create such a GSource for
integrating two contexts.
Note that the use-case here is limited: the integrated, inner main context must
not be explicitly iterated except from being dispatched by the integrating
source. Otherwise, you'd get recursive runs, possible deadlocks and general
ugliness. NMClient must show restrain how to use the inner context while it is
integrated.
Add a new 'carrier' flag to the InterfaceFlags property of devices to
indicate the current carrier state.
The new flag is equivalent to the 'lower-up' flag for all devices
except the ones that use a non-standard carrier detection mechanism
like NMDeviceAdsl.
Add a new read-only "InterfaceFlags" property to the Device interface
to export via D-Bus kernel flags and possibly other NM specific
flags. At the moment IFF_UP and IFF_LOWERUP are implemented.
This essentially aligns the implementation with the documentation.
It is also rather useful, since it allows us to use the value returned
by nm_setting_wired_get_mac_address() directly, and that one can indeed
be NULL.
The only contributors to this code are Red Hat employees who agree
with this license change.
$ git log --pretty=format:'%Cred%h%Creset - %Cgreen(%ai)%Creset [%C(yellow)%an%Creset] %s%C(yellow)%d%Creset' --no-merges -- 'libnm-core/nm-json.?' 'libnm-core/nm-jansson.?'
...
$ git shortlog -s --no-merges -- 'libnm-core/nm-json.?' 'libnm-core/nm-jansson.?'
1 Beniamino Galvani
1 Lubomir Rintel
8 Thomas Haller
Signed-off-by: Beniamino Galvani <bgalvani@redhat.com>
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Thomas Haller <thaller@redhat.com>
The library should not print to stdout/stderr. This function is used to
convert untrusted(!!) input to a normalized and sanitized strv array.
g_warning() is essentially an assertion, and it's wrong to do that
for untrusted data. If the caller had to pre-validate the array, then
having this function would be pointless.
Note that D-Bus is fundamentally asynchronous. Doing blocking calls
on top of D-Bus is odd, especially for libnm's NMClient. That is because
NMClient essentially is a client-side cache of the objects from the D-Bus
interface. This cache should be filled exclusively by (asynchronous) D-Bus
events (PropertiesChanged). So, making a blocking D-Bus call means to wait
for a response and return it, while queuing all messages that are received
in the meantime.
Basically there are three ways how a synchronous API on NMClient could behave:
1) the call just calls g_dbus_connection_call_sync(). This means
that libnm sends a D-Bus request via GDBusConnection, and blockingly
waits for the response. All D-Bus messages that get received in the
meantime are queued in the GMainContext that belongs to NMClient.
That means, none of these D-Bus events are processed until we
iterate the GMainContext after the call returns. The effect is,
that NMClient (and all cached objects in there) are unaffected by
the D-Bus request.
Most of the synchronous API calls in libnm are of this kind.
The problem is that the strict ordering of D-Bus events gets
violated.
For some API this is not an immediate problem. Take for example
nm_device_wifi_request_scan(). The call merely blockingly tells
NetworkManager to start scanning, but since NetworkManager's D-Bus
API does not directly expose any state that tells whether we are
currently scanning, this out of order processing of the D-Bus
request is a small issue.
The problem is more obvious for nm_client_networking_set_enabled().
After calling it, NM_CLIENT_NETWORKING_ENABLED is still unaffected
and unchanged, because the PropertiesChanged signal from D-Bus
is not yet processed.
This means, while you make such a blocking call, NMClient's state
does not change. But usually you perform the synchronous call
to change some state. In this form, the blocking call is not useful,
because NMClient only changes the state after iterating the GMainContext,
and not after the blocking call returns.
2) like 1), but after making the blocking g_dbus_connection_call_sync(),
update the NMClient cache artificially. This is what
nm_manager_check_connectivity() does, to "fix" bgo#784629.
This also has the problem of out-of-order events, but it kinda
solves the problem of not changing the state during the blocking
call. But it does so by hacking the state of the cache. I think
this is really wrong because the state should only be updated from
the ordered stream of D-Bus messages (PropertiesChanged signal and
similar). When libnm decides to modify the state, there may be already
D-Bus messages queued that affect this very state.
3) instead of calling g_dbus_connection_call_sync(), use the
asynchronous g_dbus_connection_call(). If we would use a sepaate
GMainContext for all D-Bus related calls, we could ensure that
while we block for the response, we iterate that internal main context.
This might be nice, because all events are processed in order and
after the blocking call returns, the NMClient state is up to date.
The are problems however: current blocking API does not do this,
so it's a significant change in behavior. Also, it might be
unexpected to the user that during the blocking call the entire
content of NMClient's cache might change and all pointers to the
cache might be invalidated. Also, of course NMClient would invoke
signals for all the changes that happen.
Another problem is that this would be more effort to implement
and it involves a small performance overhead for all D-Bus related
calls (because we have to serialize all events in an internal
GMainContext first and then invoke them on the caller's context).
Also, if the users wants this behavior, they could implement it themself
by running libnm in their own GMainContext. Note that libnm might
have bugs to make that really working, but that should be fixed
instead of adding such synchrnous API behavior.
Read also [1], for why blocking calls are wrong.
[1] https://smcv.pseudorandom.co.uk/2008/11/nonblocking/
So, all possible behaviors for synchronous API have severe behavioural
issues. Mark all this API as deprecated. Also, this serves the purpose of
identifying blocking D-Bus calls in libnm.
Note that "deprecated" here does not really mean that the API is going
to be removed. We don't break API. The user may:
- continue to use this API. It's deprecated, awkward and discouraged,
but if it works, by all means use it.
- use asynchronous API. That's the only sensible way to use D-Bus.
If libnm lacks a certain asynchronous counterpart, it should be
added.
- use GDBusConnection directly. There really isn't anything wrong
with D-Bus or GDBusConnection. This deprecated API is just a wrapper
around g_dbus_connection_call_sync(). You may call it directly
without feeling dirty.
---
The only other remainging API is the synchronous GInitable call for
NMClient. That is an entirely separate beast and not particularly
wrong (from an API point of view).
Note that synchronous API in NMSecretAgentOld, NMVpnPluginOld and
NMVpnServicePlugin as not deprecated here. These types are not part
of the D-Bus cache and while they have similar issues, it's less severe
because they have less state.
There are different enum files created that make use of different
template files. However, `mkenums_simple` method allows the creation
of the same enum files without the need of template files.
The creation of the `nm-core-enum-types` and
`nm-core-tests-enum-types` use now `mkenums_simple` so template
files are now unnecessary.
All variables used in every test have been moved to the start of the
build file.
Generated enum sources variable has been renamed to `enum_sources`
to clearly specify what it is holding.
The `libnm-core` build file has been improved by applying a set of
changes:
- Indentation has been fixed to be consistent.
- Library variable names have been changed to `lib{name}` pattern
following their filename pattern.
- `shared` prefix has been removed from all variables using it.
- Dependencies have been reviewed to store the necessary data.
- The use of the libraries and dependencies created in this file
has been reviewed through the entire source code. This has
required the addition or the removal of different libraries and
dependencies in different targets.
- Some files used directly with the `files` function have been moved
to their nearest path build file because meson stores their full
path seamessly and they can be used anywhere later.
There are multiple conditional steps for building encryption
support. This is because the support varies from `gnutls` or `nss`.
This has been improved to reduce the number of used conditions.
The `nm-default.h` header is used widely in the code by many
targets. This header includes different headers and needs different
libraries depending the compilation flags.
A new set of `*nm_default_dep` dependencies have been created to
ease the inclusion of different directorires and libraries.
This allows cleaner build files and avoiding linking unnecessary
libraries so this has been applied allowing the removal of some
dependencies involving the linking of unnecessary libraries.
The `shared` build file has been improved by applying a set of
changes:
- Indentation has been fixed to be consistent.
- Unused libraries and dependencies have been removed.
- Dependencies have been reviewed to store the necessary data.
- Set of objects used in targets have been grouped together.
- Header files have been removed from sources lists as it's
unnecessary.
- Library variable names have been changed to `lib{name}` pattern
following their filename pattern.
- `shared` prefix has been removed from all variables using it.
- `version_header` its related configuration `version_conf`
variables have been renamed to `nm_version_macro*` following
its input and final file names.
"nm-setting.c" (and property_to_dbus()) should stay independent of
actualy settings implementations. Instead, the property-info should
control the behavior.
What I like about this change is also that the generic handling is not a
flags "handle_secrets_for_vpn", but it just says to skip checking the
param-spec flags and directly call the to_dbus_fcn(). It's just a
generally useful thing to do, to let the to_dbus_fcn() function also
handle checking the property flags. The fact that only vpn.secrets
properties uses this for a certain pupose, is abstracted in a way that
makes sense.
The idea was that properties that are implemented via GENDATA still
could have a GObject property. As such, they would be marked with
this flag.
Currently, gendata properties are only implemented by NMSettingEthtool,
and there are no GObject properties where this flag is used. While it
might make sense in theory or in the future, it is unused.
Drop it.
We use the "properties_override" GArray to construct the list of property infos.
But as we append values to the GArray, the buffer grows exponentially and likely
is larger than the actually used number of values.
As this data is kept until the end of the program, let's not waste the over-allocated
memory and instead copy it to a buffer of the right size.
We have too many _properties_override_add*() variants. They basically are all the
same. Drop _properties_override_add_dbus_only() and use _properties_override_add_virt()
instead.
Also, I am always confused by the term "synth". We shouldn't treat
non-GObject-based properties as somehow odd that need to be synthesized.
In total, we register 447 property informations. Out of these,
326 are plain, GObject property based without special implementations.
The NMSettInfoProperty had all function pointers directly embedded,
currently this amounts to 5 function pointers and the "dbus_type" field.
That means, at runtime we have 326 times trivial implementations with
waste 326*6*8 bytes of NULL pointers. We can compact these by moving
them to a separate structure.
Before:
447 * 5 function pointers
447 * "dbus_type" pointer
= 2682 pointers
After:
447 * 1 pointers (for NMSettInfoProperty.property_type)
89 * 6 pointers (for the distinct NMSettInfoPropertType data)
= 981 pointers
So, in total this saves 13608 byes of runtime memory (on 64 bit arch).
The 89 NMSettInfoPropertType instances are the remaining distinct instances.
Note that every NMSettInfoProperty has a "property_type" pointer, but most of them are
shared. That is because the underlying type and the operations are the same.
Also nice is that the NMSettInfoPropertType are actually constant,
static fields and initialized very early.
This change also makes sense form a design point of view. Previously,
NMSettInfoProperty contained both per-property data (the "name") but
also the behavior. Now, the "behavioral" part is moved to a separate
structure (where it is also shared). That means, the parts that are
concerned with the type of the property (the behavior) are separate
from the actual data of the property.
