It is redundant to store 'hash' and 'compare' function pointers in
struct Hashmap separately. The functions always comprise a pair.
Store a single pointer to struct hash_ops instead.
systemd keeps hundreds of hashmaps, so this saves a little bit of
memory.
THis was accidentally broken, as we truned off LLMNR far to frequently,
where we only wanted to turn off LLMNr on IPV6 on kernels lacking
support for it.
We now maintain two lists of DNS servers: system servers and fallback
servers.
system servers are used in combination with any per-link servers.
fallback servers are only used if there are no system servers or
per-link servers configured.
The system server list is supposed to be populated from a foreign tool's
/etc/resolv.conf (not implemented yet).
Also adds a configuration switch for LLMNR, that allows configuring
whether LLMNR shall be used simply for resolving or also for responding.
This avoids having to distinguish between IPv4 and IPv6, allowing us
to keep their internal orderings. The consumers now has to turn the
strings into addresses.
networkd will expose both statically configured DNS servers and servers
receieved over DHCP in sd_network_get_dns(), so no need to keep
the distinction in resolved.
Let's settle on a single type for all address family values, even if
UNIX is very inconsitent on the precise type otherwise. Given that
socket() is the primary entrypoint for the sockets API, and that uses
"int", and "int" is relatively simple and generic, we settle on "int"
for this.
As long as the number of array entries is relatively small it's nicer to
simply return the number of entries directly, instead of using a size_t*
return parameter for it.
Let's turn resolved into a something truly useful: a fully asynchronous
DNS stub resolver that subscribes to network changes.
(More to come: caching, LLMNR, mDNS/DNS-SD, DNSSEC, IDN, NSS module)
