Allow configuration for IPv6 discovered routes to be ignored instead of
adding them as a route. This can be used to block unwanted routes, for
example, you may wish to not receive some set of routes on an interface
if they are causing issues.
Let's clean up hostname_is_valid() a bit: let's turn the second boolean
argument into a more explanatory flags field, and add a flag that
accepts the special name ".host" as valid. This is useful for the
container logic, where the special hostname ".host" refers to the "root
container", i.e. the host system itself, and can be specified at various
places.
let's also get rid of machine_name_is_valid(). It was just an alias,
which is confusing and even more so now that we have the flags param.
They are not really boolean, because we have both ipv4 and ipv6, but
for each protocol we have either unset, no, and yes.
From https://github.com/systemd/systemd/issues/13316#issuecomment-582906817:
LinkLocalAddressing must be a boolean option, at least for ipv4:
- LinkLocalAddressing=no => no LL at all.
- LinkLocalAddressing=yes + Static Address => invalid configuration, warn and
interpret as LinkLocalAddressing=no, no LL at all.
(we check that during parsing and reject)
- LinkLocalAddressing=yes + DHCP => LL process should be subordinated to the
DHCP one, an LL address must be acquired at start or after a short N
unsuccessful DHCP attemps, and must not stop DHCP to keeping trying. When a
DHCP address is acquired, drop the LL address. If the DHCP address is lost,
re-adquire a new LL address.
(next patch will move in this direction)
- LinkLocalAddressing=fallback has no reason to exist, because LL address must
always be allocated as a fallback option when using DHCP. Having both DHCP
and LL address at the same time is an RFC violation, so
LinkLocalAdressing=yes correctly implemented is already the "fallback"
behavior. The fallback option must be deprecated and if present in older
configs must be interpreted as LinkLocalAddressing=yes.
(removed)
- And for IPv6, the LinkLocalAddress option has any sense at all? IPv6-LL
address aren't required to be always set for every IPv6 enabled interface (in
this case, coexisting with static or dynamic address if any)? Shouldn't be
always =yes?
(good question)
This effectively reverts 29e81083bd. There is no
special "fallback" mode now, so the check doesn't make sense anymore.
The configuration of networkd has a DHCPv6Client setting in its
[IPv6AcceptRA] section, which, according to the man page, can be
a boolean, or the special value "always". The man page states
that "true" is the default.
The default value is implemented in src/network/networkd-network.c
by setting field ipv6_accept_ra_start_dhcp6_client of network to
true. However, this field is not a boolean, but an enum type
IPv6AcceptRAStartDHCP6Client (src/network/networkd-ndisc.h).
Setting ipv6_accept_ra_start_dhcp6_client to true effectively
corresponds to the enum value IPV6_ACCEPT_RA_START_DHCP6_CLIENT_ALWAYS,
resulting in the DHCPv6Client setting having the default value
"always".
This patch changes the initialisation to the correct enum value
IPV6_ACCEPT_RA_START_DHCP6_CLIENT_YES.
Susant Sahani