Implements IPv4LL with respect to RFC 3927
(http://tools.ietf.org/rfc/rfc3927.txt) and integrates it
with networkd. Majority of the IPv4LL state machine is
taken from avahi (http://avahi.org/) project's autoip.
IPv4LL can be enabled by IPv4LL=yes under [Network]
section of .network file.
IPv4LL works independent of DHCP but if DHCP lease is
aquired, then LL address will be dropped.
[tomegun: removed a trailing newline and a compiler warning]
This is mostly a proof of concept to try sd-network, so we don't
hook it up with a .service file quite yet. We probably want it to
be more clever about deciding when we are 'online'.
The binary will wait for at least one network managed by networkd,
and until all networks managed by networkd are configured.
Previously the returned object of constructor functions where sometimes
returned as last, sometimes as first and sometimes as second parameter.
Let's clean this up a bit. Here are the new rules:
1. The object the new object is derived from is put first, if there is any
2. The object we are creating will be returned in the next arguments
3. This is followed by any additional arguments
Rationale:
For functions that operate on an object we always put that object first.
Constructors should probably not be too different in this regard. Also,
if the additional parameters might want to use varargs which suggests to
put them last.
Note that this new scheme only applies to constructor functions, not to
all other functions. We do give a lot of freedom for those.
Note that this commit only changes the order of the new functions we
added, for old ones we accept the wrong order and leave it like that.
If -flto is used then gcc will generate a lot more warnings than before,
among them a number of use-without-initialization warnings. Most of them
without are false positives, but let's make them go away, because it
doesn't really matter.
Don't set set **ret when returning r < 0, as matching on the errno may easily
give false positives in the future leading to null pointer dereference.
Reported-by: David Herrmann <dh.herrmann@gmail.com>
So far we followed the rule to always indicate the "flavour" of
constructors after the "_new_" or "_open_" in the function name, so
let's keep things in sync here for rtnl and do the same.
The "sd_" prefix is supposed to be used on exported symbols only, and
not in the middle of names. Let's drop it from the cleanup macros hence,
to make things simpler.
The bus cleanup macros don't carry the "sd_" either, so this brings the
APIs a bit nearer.
Udev does not run in containers, so instead of relying on it to tell us when a
network device is ready to be used by networkd, we simply assume that any
device was fully initialized before being added to the container.
Also limit the range of vlan ids. Other implementations and
documentation use the ranges {0,1}-{4094,4095}, but we use
the one accepted by the kernel: 0-4094.
Reported-by: Oleksii Shevchuk <alxchk@gmail.com>
This allows us users of the library to keep copies of old leases. This is
used by networkd to know what addresses to drop (if any) when the lease
expires.
In the future this may be used by DNAv4 and sd-dhcp-server.
The kernel will not be changed to support this, so drop the code. Listening
for all RTM_NEWLINK messages and filtering on name is reliable, so it is not
a problem.
When creating a new link, the kernel will not inform us about the new ifindex
in its ack. We have to listen for newly created devices and deduce the new
ifindex by matching on the ifname.
We used to do this by waiting for a new device from libudev, but that is asking
for trouble, as udev will happily rename the device before handing it to us.
Listen on rtnl instead, the chance of the name being changed before reaching us
is much smaller (if not nil).
Kernel patch in the works to make this unneccessary.
These connections are never torn down, even when the DHCP specifications say that
they should be. This is useful/necessary when the rootfs (or another critical fs)
is mounted over this network connection, and dataloss would result if the connection
is lost.
This option defaults to off, but our initrd generator (TBD) will enable it when
applicable.
Umut Tezduyar Lindskog