This shall contain type definitions, with similar use
to "nm-core-internal.h".
However, it should contain a minimal set, so that we can include this
header in other headers under "src/", without including the whole
"nm-core-internal.h" in headers.
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.
Usually, the peer-address is the same as the local address.
In case where it is not, it is the peer-address that determines
the IPv4 device-route. So we must use the peer-address.
Also, don't consider device-routes with the first octet of zero,
just like kernel does.
Also, nm_ip4_config_get_subnet_for_host() is effectively the same
as nm_ip4_config_destination_is_direct(). So drop it.
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.
The program ran over the platform links and printed them.
Our to-string methods of platform objects are already supposed
to print all fields. So this only duplicates code to print a link.
If you want to see what links were picked up by platfrom run:
NMTST_DEBUG=log-level=TRACE ./src/platform/tests/monitor
or just
./src/platform/tests/monitor
Yes, this has less the iproute2 feeling, but it gives you a more
native access to the platform objects -- which is what you want
for debugging platform.
Previously, while detecting the link type we would lookup the
@kind in case it was missing.
Now, go one step further, and also prefer the link-type from the
cache.
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.
For link objects, nmp_object_cmp() did not consider the private fields and
thus behaved different then nmp_object_equal(). This is wrong.
Implement nmp_object_equal() based on compare.
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
