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]
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.
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.
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.
Make them more simiar to sd_bus and friends. Also factor out the event attachment. In the future,
we will likely want to support external main-loops, so this is a first step. For the time being,
we are still requiring an sd_event to be attached though.
We may not have a dbus daemon in the initrd (until we can rely on kdbus). In
this case, simply ignore any attempts at using the bus. There is only one user
for now, but surely more to come.
In order to work reliably in the real root without kdbus, but at the same time
don't delay boot when kdbus is in use, order ourselves after dbus.service.
This adds support to generate a basic resolv.conf in /run/systemd/network.
This file will not take any effect unless a symlink is created from
/etc/resolv.conf.
Nameservers received over DHCP takes precedence over statically configured ones.
Note: /etc/resolv.conf is severely limited, so in the future we will likely
rather provide a much more powerfull nss plugin (or something to that effect),
but this should allow current users to function without any loss of
functionality.
It seems that networkd stores in_addr.s_addr contents in reverse
order (little-endian, not network order). This is a bit confusing,
but sd_rtnl evidently likes this order.
This adds basic DHCPv4 support. Link-sense is enabled unconditionally,
but the plan is to make that configurable.
I tested this in a VM with lots of NICs and over wifi in the various
coffee shops I found this Christmas, but more testing would definitely
be appreciated.
Static addresses/routes are associated with a network. Dynamic
addresses/routes are associtade with links (as the corresponding network
may be shared by several links).
This listens to rtnetlink for changes to IFF_UP and IFF_LOWER_UP (link sense). The latter
is simply logged at the moment, but will be useful once we add dhcp support.
A bridge is specified in a .netdev file with a section [Bridge]
and at least the entry Name=.
A link may be joined to a bridge if the .network applied to it has
a Bridge= entry giving the name of the bridge in its [Network] section.
We eagerly create all bridges on startup, and links are added to
bridges as soon as they both appear.
This daemon listens for and configures network devices tagged with
'systemd-networkd'. By default, no devices are tagged so this daemon
can safely run in parallel with existing network daemons/scripts.
Networks are configured in /etc/systemd/network/*.network. The first .network
file that matches a given link is applied. The matching logic is similar to
the one for .link files, but additionally supports matching on interface name.
The mid-term aim is to provide an alternative to ad-hoc scripts currently used
in initrd's and for wired setups that don't change much (e.g., as seen on
servers/and some embedded systems).
Currently, static addresses and a gateway can be configured.
Example .network file:
[Match]
Name=wlp2s0
[Network]
Description=My Network
Gateway=192.168.1.1
Address=192.168.1.23/24
Address=fe80::9aee:94ff:fe3f:c618/64
Tom Gundersen