link_radv_enabled() and link_ndisc_enabled() use
link_ipv6ll_enabled_harder(), which considers a static fe80:: address
in [Address] sufficient to run radv/ndisc even when LinkLocalAddressing=
(or IPv6LinkLocalAddressGenerationMode=none, which network_verify()
folds into the same flag) disables the kernel-generated link-local.
network_adjust_radv()/ndisc()/dhcp() however only check the raw
link_local flag and zero router_prefix_delegation / ndisc / dhcp&IPV6
at parse time, so the runtime gate never gets a chance to fire.
Factor the static-LL lookup out of link_ipv6ll_enabled_harder() into a
Network-level helper and use it in the three network_adjust_*()
functions, bringing parse-time and runtime behaviour in line.
Let's introduce these for the following two reasons:
- Using them makes sure the parameter names match between declaration
and definition (if both use the corresponding macros).
- They make sure developers can't forget the _const_ and _pure_
attributes for the declarations.
This commit also includes some include sorting fixes
This renames and splits link_may_have_ipv6ll() into
link_ipv6ll_enabled_harder() and link_multicast_enabled(),
as they are completely irrelevant to each other.
Also, this makes link_ipv6ll_enabled_harder() work non-Wireguard
interfaces.
Try to ensure kernel IPv6 link local address generation occurs by
setting the per-if addr_gen_mode sysctl when the link is already up,
instead of the netlink interface (IFLA_INET6_ADDR_GEN_MODE).
The netlink setting is sufficient in cases where the interface is not
yet up when networkd configures an interface - bringing the interface
up will trigger in-kernel address generation.
If the interface is already up, yet the interface has no IPv6LL assigned
setting IFLA_INET6_ADDR_GEN_MODE has no effect.
Writing the addr_gen_mode sysctl is a best effort attempt at triggering
address generation regardless of interface state because it also works
in cases where the interface is already up.
Fixes#22424.
r-vdp
Daan De Meyer
Yu Watanabe
Joerie de Gram