Support managing the loopback interface through NM as the users want to
set the proper mtu for loopback interface when forwarding the packets.
Additionally, the IP addresses, DNS, route and routing rules are also
allowed to configure for the loopback connection profiles.
https://bugzilla.redhat.com/show_bug.cgi?id=2060905
DHCP leases for a given interface are already exported on D-Bus
through DHCP4Config and DHCP6Config objects. It is useful to have the
same information also available on the filesystem so that it can be
easily used by scripts.
NM already saves some information about DHCP leases in /var, however
that directory can only be accessed by root, for good reasons.
Append lease options to the existing state file
/run/NetworkManager/devices/$ifindex. Contrary to /var this directory
is not persistent, but it seems more correct to expose the lease only
when it is active and not after it expired or after a reboot.
Since the file is in keyfile format, we add new [dhcp4] and [dhcp6]
sections; however, since some options have the same name for DHCPv4
and DHCPv6, we add a "dhcp4." or "dhcp6." prefix to make the parsing
by scripts (e.g. via "grep") easier.
The option name is the same we use on D-Bus. Since some DHCPv6 options
also have a "dhcp6_" prefix, the key name can contain "dhcp6" twice.
The new sections look like this:
[dhcp4]
dhcp4.broadcast_address=172.25.1.255
dhcp4.dhcp_lease_time=120
dhcp4.dhcp_server_identifier=172.25.1.4
dhcp4.domain_name_servers=172.25.1.4
dhcp4.domain_search=example.com
dhcp4.expiry=1641214444
dhcp4.ip_address=172.25.1.182
dhcp4.next_server=172.25.1.4
dhcp4.routers=172.25.1.4
dhcp4.subnet_mask=255.255.255.0
[dhcp6]
dhcp6.dhcp6_name_servers=fd01::1
dhcp6.dhcp6_ntp_servers=ntp.example.com
dhcp6.ip6_address=fd01::1aa
The order of addresses matters. For "ipv4.addresses", the list
contains the primary address first. For "ipv6.addresses", the
order was reverted. This was also documented behavior.
The previous patch just changed behavior with respect to relative order
of static IPv6 addresses and autoconf6/DHCPv6. As we seem in the mood
for changing behavior, here is another one.
Now the addresses are interpreted in an order consistent with IPv4 and
how one might expect: preferred addresses first.
The order of addresses can matter for source address selection.
This is described in RFC 6724 section 5, but if the rules don't
determine a clear winner, the order matters.
Change the relative order of IPv6 addresses. Previously, we would prefer
autoconf6, over DHCPv6, over manual addresses. Now that got reverted
to make more sense and be consistent with IPv4.
Also, if we had multiple autoconf6 addresses (received at different
moments in time), then previously a newly received address would be
added with highest priority. Now, the older address will be preferred
and that order will be enforced (this can be a problem, see (*) below).
For IPv4, it's all simple and sensible. When we add addresses in kernel
via netlink, the first address (of a subnet) becomes the primary.
Note that we only control the order of addresses of the same subnet.
The addresses in ipv4.addresses" are sorted with primary address first.
In the same way is the order for addresses in NML3ConfigData and for
@known_addresses in nm_platform_ip_address_sync(), all primary-first.
Also, manual addresses are sorted with higher priority compared to DHCPv4
addresses (at least since NetworkManager 1.36). That means the way how we
merge NML3ConfigData makes sense (nm_l3_config_data_merge()) because we first
merge the static configuration, then the DHCPv4 configuration, where we just
append the lower priority DHCPv4 addresses.
For IPv6, the address priority is messed up. On netlink/kernel, the last added
address becomes the preferred one (we thus need to add them in the order of
lowest priority first). Consequently and historically, the IPv6 addresses in
@known_addresses parameter to nm_platform_ip_address_sync() were
lowest priority first. And so they were tracked in NML3ConfigData
and in the profile ("ipv6.addresses"). That is confusing.
Also, we usually want to merge NML3ConfigData with different priorities
(e.g. static configuration from the profile before autoconf6/DHCPv6),
as we do with IPv4. However, since internally IPv6 addresses are tracked in
reverse order, it means later NML3ConfigData would be appended and get effectively
a higher priority. That means, autoconf6 addresses were preferred over DHCPv6 and
over manual "ipv6.addresses", respectively. That seems undesirable and inconsistent
with IPv4. Change that. This is a change in behavior.
Note that changing the order of addresses means to remove and re-add
them in the right (inverse) order, with lease important first. This
means, when we add a new address with lower priority, we need to remove
all higher priority addresses temporarily, before readding them. That
is a problem(*).
Note that in the profile, "ipv6.addresses" is still tracked in reverse
order. This did not change, but might change later.
This adds a global "--offline" option and allows its use with "add" and
"modify" commands. The "add" looks like this:
$ nmcli --offline conn add type ethernet ens3 ipv4.dns 192.168.1.1 \
>output.nmconnection
The "modify" is essentially implementing what's been suggested by
Beniamino in bugzilla ticked (referred to below):
$ nmcli --offline connection modify ens3 ipv4.dns 192.168.1.1 \
<input.nmconnection >output.nmconnection
Other commands don't support the argument at the moment:
$ nmcli --offline c up ens3
Error: 'up' command doesn't support --offline mode.
https://bugzilla.redhat.com/show_bug.cgi?id=1361145
This is long replaced by nettools' n-dhcp4 client.
Drop it.
We still require NMDhcpSystemd for the DHCPv6 client.
Note that "[main].dhcp=systemd" now falls back to the internal client.
But this option was undocumented and internal anyway.
Currently it is possible to specify a list of default settings plugins
to be used when configuration doesn't contain the main.plugins key.
We want to add a mechanism that allows to automatically load any
plugin found in the plugins directory without needing
configuration. This mechanism is useful when plugins are shipped in a
different, optional subpackage, to automatically use them.
With such mechanism, the actual list of plugins will be determined
(in order of evaluation):
1. via explicit user configuration in /etc, if any
2. via distro configuration in /usr, if any
3. using the build-time default, if any
4. looking for known plugins in /usr/lib
This paragraph that "it's likely that" some changes will be backported
to 1.34 branch seems unnecessary. Whenever we backport things to 1.34
we will add them to the NEWS file for nm-1-34, and then also mention
them in nm-1-36 and newer. But we don't need to announce that.
