With g_return() we try to catch wrong invocations of a function
or passing invalid arguments.
Having ~forgot~ to overwrite a virtual function is such a serious
and fundamental issue, that checking for it at runtime is wasteful
and unnessesary.
If we ever hit such a situation, just crash.
Link related functions should have a "nm_platform_link" prefix. Rename.
Naming is a subjective matter and one might argue that omitting
the "link" part from the name is shorter and even preferred.
However, I think functions related to links should have a common
prefix as the underlyings are strongly related.
Let the link-add functions return the internal pointer to the platform
link object. Similar to link-get, which doesn't copy the link either.
Also adjust the sole users of the add-functions (create-and-realize)
to take the pointer.
Eventually we still copy the returned data, because accessing platform can
invalidate the returned pointer. Thus we don't actually safe any copying
by this (at least every use of the function currently leads to the data
being copied).
Still change it, because I think the API of NMPlatform should look like that.
We potentially emit a lot of signals. Don't look up the
signal by name because that adds quite some additional
overhead, like peeking for a GQuark.
Instead pass the numeric signal-id directly.
This enum was unused and meaningless because the platform signals
are emitted as a consequence of netlink messages. It is not clear
whether a netlink message was received due to an external event
or an internal action.
Previsously, _LOGT() could be disabled at compile time. Thus it
was different then the other macros _LOGD(), _LOGI(), etc.
OTOH, _LOGt() was the macro that always was compiled in.
Swap the name of the macros. Now the upper-case macros are always
enabled, while the lower-case macro _LOGt() is enabled depending
on compile configuration.
Previously, we could only set the ingress-qos-mappings/egress-qos-mappings.
Now also cache the mappings and expose them from the platform cache.
Also, support changing the vlan flags not only when creating the vlan
interface.
Instead of using libnl-route-3 library to serialize netlink messages,
construct the netlink messages ourselves.
This has several advantages:
- Creating the netlink message ourself is actually more straight
forward then having an intermediate layer between NM and the kernel.
Now it is immediately clear, how a platform request translates to
a netlink/kernel request.
You can look at the kernel sources how a certain netlink attribute
behaves, and then it's immediately clear how to set that (and vice
versa).
- Older libnl versions might have bugs or missing features for which
we needed to workaround (often by offering a reduced/broken/untested
functionality). Now we can get rid or workaround like _nl_has_capability(),
check_support_libnl_extended_ifa_flags(), HAVE_LIBNL_INET6_TOKEN.
Another example is a libnl bug when setting vlan ingress map which
isn't even yet fixed in libnl upstream.
- We no longer need libnl-route-3 at all and can drop that runtime
requirement, saving some 400k.
Constructing the messages ourselves also gives better performance
because we don't have to create the intermediate libnl object.
- In the future we will add more link-type support which is easier
to support by basing directly on the plain kernel/netlink API,
instead of requiring also libnl3 to expose this functionality.
E.g. adding macvtap support: we already parsed macvtap properties
ourselves because of missing libnl support. To *add* macvtap
support, we also would have to do it ourself (or extend libnl).
Having a static string buffer for convenience is useful not only
for platform. Define the string buffer in NetworkManagerUtils.h,
so that all to-string functions can reuse *one* buffer.
Of course, this has the potential danger, that different
to-string method might reuse the same buffer. Hence, low-level
library functions are adviced to use their own buffer, because
an upper level might already use the global buffer for another
string.
The peer-address (IFA_ADDRESS) can also be all-zero (0.0.0.0).
That is distinct from an usual address without explicit peer-address,
which implicitly has the same peer and local address.
Previously, we treated an all-zero peer_address as having peer and
local address equal. This is especially grave, because the peer is part
of the primary key for an IPv4 address. So we not only get a property of
the address wrong, but we wrongly consider two different addresses as
one and the same.
To properly handle these addresses, we always must explicitly set the peer.
We already have nm_platform_tun_get_properties(). Rename the function
as they both sidestep the platform cache to lookup some link-specific
properties.
For recent kernels, the peer-ifindex of veths is reported as
parent (IFA_LINK). Prefer that over the ethtool lookup.
For one, this avoids the extra ethtool call which has the
downside of sidestepping the platform cache. Also, looking
up the peer-ifindex in ethtool does not report whether the
peer lifes in another netns (NM_PLATFORM_LINK_OTHER_NETNS).
Only use ethtool as fallback for older kernels.
Constructing the libnl3 object only to parse the message
is wasteful. It involves several memory allocations, thread
synchronization and parsing fields that we don't care about.
But moreover, older libnl version might not support all the
fields we are interested in, hence we have workarounds like
_nl_link_parse_info_data(). Certain features might not fully
work unless libnl supports it too (although kernel would).
As we already parse the data ourselves sometimes, just go
all they way and don't construct the intermediate libnl object.
This will allow us to drop the _nl_link_parse_info_data() workarounds
in next commits. That is important, because _nl_link_parse_info_data()
sidesteps our platform cache and is not in sync with the cache (not to
mention the extra work to explicitly refetch the data on every lookup).
Also, it gets us 60% on the way to no longer needing 'libnl-route-3.so'
at all and eventually drop requiring the library.
This function only accesses sysctl function to retrieve the tun-properties.
sysctl is already defined in the base class and equally inherited by linux
and fake platform. Move the implementation there.
Arguably, it is more convenient to use the static buffer as
it saves typing.
But having such a low-level function use a static buffer also
limits the way how to use it. As it was, you could not avoid
using the static buffer.
E.g. you cannot do:
char buf[100];
_LOGD ("nmp-object: %s; platform-link: %s",
nmp_object_to_string (nmpobj, buf, sizeof(buf)),
nm_platform_link_to_string (link));
This will fail for non-obvious reasons because both
to-string functions end up using the same static buffer.
Also change the to-string implementations to accept NULL
as valid and return it as "(null)".
https://bugzilla.gnome.org/show_bug.cgi?id=756427
Kernel allows to add the same IPv4 address that only differs by
peer-address (IFL_ADDRESS):
$ ip link add dummy type dummy
$ ip address add 1.1.1.1 peer 1.1.1.3/24 dev dummy
$ ip address add 1.1.1.1 peer 1.1.1.4/24 dev dummy
RTNETLINK answers: File exists
$ ip address add 1.1.1.1 peer 1.1.2.3/24 dev dummy
$ ip address show dev dummy
2: dummy@NONE: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default
link/ether 52:58:a7:1e:e8:93 brd ff:ff:ff:ff:ff:ff
inet 1.1.1.1 peer 1.1.1.3/24 scope global dummy
valid_lft forever preferred_lft forever
inet 1.1.1.1 peer 1.1.2.3/24 scope global dummy
valid_lft forever preferred_lft forever
We must also consider peer-address, otherwise platform will treat
two different addresses as one and the same.
https://bugzilla.gnome.org/show_bug.cgi?id=756356
The peer-address seems less important then the prefix-length.
Also, nm_platform_ip4_address_delete() has the peer-address
argument as last.
Soon ip4_address_get() also receives a peer-address argument,
so get the order right first.
The parent of a link (IFLA_LINK) can be in another network namespace and
thus invisible to NM.
This requires the netlink attribute IFLA_LINK_NETNSID which is supported
by recent versions of kernel and libnl.
In this case, set the parent field to NM_PLATFORM_LINK_OTHER_NETNS
and properly handle this special case.
The logging macros _LOGD(), etc. are specific to each
file as they format the message according to their context.
Still, they were cumbersome to define and their implementation
was repeated over and over (slightly different at times).
Move the declaration of these macros to "nm-logging.h".
The source file now only needs to define _NMLOG(), and either
_NMLOG_ENABLED() or _NMLOG_DOMAIN.
This reduces code duplication and encourages a common implementation
and usage of these macros.
