Otherwise:
eth0: unknown link flags gained: 0x00040 (ignoring)
[tomegun: hiding these messages is ok, as IFF_RUNNING is redundant
and can be deduced from operstate and IFF_LOWER_UP]
To make sure we don't delay boot on systems where (some) network links are managed by someone else
we don't block if something else has successfully brought up a link.
We will still block until all links we are aware of that are managed by networkd have been
configured, but if no such links exist, and someone else have configured a link sufficiently
that it has a carrier, it may be that the link is ready so we should no longer block.
Note that in all likelyhood the link is not ready (no addresses/routes configured),
so whatever network managment daemon configured it should provide a similar wait-online
service to block network-online.target until it is ready.
The aim is to block as long as we know networking is not fully configured, but no longer. This
will allow systemd-networkd-wait-online.service to be enabled on any system, even if we don't
know whether networkd is the main/only network manager.
Even in the case networking is fully configured by networkd, the default behavior may not be
sufficient: if two links need to be configured, but the first is fully configured before the
second one appears we will assume the network is up. To work around that, we allow specifying
specific devices to wait for before considering the network up.
This unit is enabled by default, just like systemd-networkd, but will only be pulled in if
anyone pulls in network-online.target.
This properly detects the state of the link based on both the link flags and the
operstate.
Moreover, always log state-changes even if we are not yet managing the link.
Avoid having two code-paths racing with eacother to do the same thing. The change
of flags will be detected in the normal way, so only use the link_up_handler
to detect if the 'up' failed and in that case fail the link.
This essentially swaps the roles of rtnl and udev in networkd. After this
change libudev is only used for waiting for udev to initialize devices and
to get udev-specific information needed for some [Match] attributes.
This in particular simplifies the code in containers where udev is not really
useful, but also simplifies things and reduces round-trips in the non-container
case.
Usually RUNNING implies LOWER_UP, but for drivers that don't support oper state, RUNNING can
also mean that the state is unknown. In that case we should just trust LOWER_UP directly.
The interface is not fully ready until it enterns RUNNING. This was causing
problems with sending out DHCP messages before the interface was ready, so they
would get lost. In particular this affected DHCP INIT-REBOOT, as it relies on
the first package sent being successful (or it will fall back to a full reboot).
Also improve the logging a lot, to make future debugging of link state a lot
easier.
This error should never happen, so replace the check with an assert. The check
was anyway broken due to an uninitialized return value.
Reported by Thomas Hindoe Paaboel Andersen <phomes@gmail.com>.
Similar to DHCP, the IPv4LL library user can decide to free the LL
client any time the callback is called. Guard against freeing the
LL client in the callback by introducing proper reference counting.
Also update code using the IPv4LL library to properly handle a
returned NULL from the notify and stop functions if the IPv4LL
client was freed.
The DHCP library user can decide to free the DHCP client any time
the callback is called. After the callback has been called, other
computations may still be needed - the best example being a full
restart of the DHCP procedure in case of lease expiry.
Fix this by introducing proper reference counting. Properly handle
a returned NULL from the notify and stop functions if the DHCP
client was freed.
Currently when both ipv4ll and dhcp are enabled, ipv4ll
address (if one has been claimed) is removed when dhcp
address is aquired. This is not the best thing to do
since there might be clients unaware of the removal
trying to communicate.
This patch provides a smooth transition between ipv4ll
and dhcp. If ipv4ll address was claimed [1] before dhcp,
address is marked as deprecated. Deprecated address is still
a valid address and packets can be received on it but address
cannot be selected as a source address. If dhcp lease cannot
be extended, then ipv4ll address is marked as valid again.
[1] If there is no collision, claiming IPv4LL takes between 4 to
7 seconds.
This does not belong in shared as it is mostly a detail of our networking subsystem.
Moreover, now we can use libudev here, which will simplify things.
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.
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]
