Package resolvconf provides utility code to query and update DNS configuration in /etc/resolv.conf
GetNameservers returns nameservers (if any) listed in /etc/resolv.conf
GetNameserversAsCIDR returns nameservers (if any) listed in /etc/resolv.conf as CIDR blocks (e.g., "188.8.131.52/32") This function's output is intended for net.ParseCIDR
GetOptions returns options (if any) listed in /etc/resolv.conf If more than one options line is encountered, only the contents of the last one is returned.
GetSearchDomains returns search domains (if any) listed in /etc/resolv.conf If more than one search line is encountered, only the contents of the last one is returned.
Path returns the path to the resolv.conf file that libnetwork should use.
When /etc/resolv.conf contains 127.0.0.53 as the only nameserver, then it is assumed systemd-resolved manages DNS. Because inside the container 127.0.0.53 is not a valid DNS server, Path() returns /run/systemd/resolve/resolv.conf which is the resolv.conf that systemd-resolved generates and manages. Otherwise Path() returns /etc/resolv.conf.
Errors are silenced as they will inevitably resurface at future open/read calls.
File contains the resolv.conf content and its hash
Build writes a configuration file to path containing a "nameserver" entry for every element in dns, a "search" entry for every element in dnsSearch, and an "options" entry for every element in dnsOptions.
FilterResolvDNS cleans up the config in resolvConf. It has two main jobs: 1. It looks for localhost (127.*|::1) entries in the provided
resolv.conf, removing local nameserver entries, and, if the resulting cleaned config has no defined nameservers left, adds default DNS entries
2. Given the caller provides the enable/disable state of IPv6, the filter
code will remove all IPv6 nameservers if it is not enabled for containers
Get returns the contents of /etc/resolv.conf and its hash
GetIfChanged retrieves the host /etc/resolv.conf file, checks against the last hash and, if modified since last check, returns the bytes and new hash. This feature is used by the resolv.conf updater for containers
GetLastModified retrieves the last used contents and hash of the host resolv.conf. Used by containers updating on restart
GetSpecific returns the contents of the user specified resolv.conf file and its hash