Increase the chance of using the same link local address between reboots. The
pseudo random sequence of addresses we attempt is now seeded with data that is
very likely to stay the same between reboots, but at the same time be unique
to the specific machine/nic.
First we try to use the ID_NET_NAME_* data from the udev db combined with the
machin-id, which is guaranteed to be unique and persistent, if available. If
that is not possible (e.g., in containers where we don't have access to the
udev db) we fallback to using the MAC address of the interface, which is
guaranteed to be unique, and likely to be persistent.
[tomegun: three minor changes:
- don't expose HASH_KEY in the siphash24 header
- get rid of some compile-warnings (and some casts at the same time),
by using uint8_t[8] rather than uint64_t in the api
- added commit message]
Some DHCP servers gives you a netmask of 255.255.255.255 so the gateway is not
routable. Other DHCP client implementations look through the existing routes to
figure out if they should add an explicit host route. See below for a link.
However, it makes sense to just create the route explicitly whether it is
needed or not since it is explicit, makes the dhcp route entries independent of
other entries and saves us from knowing the state of the kernel tables.
After patch route table on a machine with a network (common case):
default via 10.0.2.2 dev ens3
10.0.2.0/24 dev ens3 proto kernel scope link src 10.0.2.15
10.0.2.2 dev ens3 scope link
After patch route table on a machine without a network (this case):
default via 10.240.0.1 dev ens4v1
10.240.0.1 dev ens4v1 scope link
The code from dhcpcd that works around this issue is on line 637.
https://android.googlesource.com/platform/external/dhcpcd/+/master/configure.c
Pass the mac address on to ipv4ll and dhcp clients so they always have
up-to-date information, and may react appropriately to the change.
Also drop setting the mac address from uevent, and only log when the
address actually changes.
safe_close() automatically becomes a NOP when a negative fd is passed,
and returns -1 unconditionally. This makes it easy to write lines like
this:
fd = safe_close(fd);
Which will close an fd if it is open, and reset the fd variable
correctly.
By making use of this new scheme we can drop a > 200 lines of code that
was required to test for non-negative fds or to reset the closed fd
variable afterwards.
Bring some arrays that are used for DEFINE_STRING_TABLE_LOOKUP() in the
same order than the enums they reference.
Also, pass the corresponding _MAX value to the array initalizer where
appropriate.
Bridges will change their MAC address when other devices are enslaved. We need
the correct MAC address to acquire a DHCP lease, so take note of it whenever
it changes.
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.
