libnss_adguard: libnss bridge to improve performance even more on localhost

[kuvaldini]

it is convenient to have local dns resolver with local cache and local configurations. AdGuard is cool solution.

there is one more way to improve dns performance with locally serviced dns resolver.
most of apps written in any language fall to glibc's function call gethostbyname() which in its order goes to libnss which is configured by

# Name Service Switch configuration file.
# See nsswitch.conf(5) for details.

passwd: files systemd
group: files [SUCCESS=merge] systemd
shadow: files systemd
gshadow: files systemd

publickey: files

#hosts: mymachines resolve [!UNAVAIL=return] files myhostname dns
hosts: mymachines files myhostname dns
networks: files

protocols: files
services: files
ethers: files
rpc: files

netgroup: files

for those who have like systemd-resolved provides libnss_resolve.so which is commented here in line #hosts

my question-suggestion is add libnss_adguardhome to make it even more faster. If you are aware about performance improvement possible using this approach please share.

here is implementation of systemd's nss-resolve https://github.com/systemd/systemd/blob/main/src/nss-resolve/nss-resolve.c