nerves_network

v0.5.5

nerves_network v0.5.5 Nerves.Network.Resolvconf

This module manages the contents of “/etc/resolv.conf”. This file is used by the C library for resolving domain names and must be kept up-to-date as links go up and down. This module assumes exclusive ownership on “/etc/resolv.conf”, so if any other code in the system tries to modify the file, their changes will be lost on the next update.

Link to this section Summary

Types

ifmap()

Settings for resolvconf

resolvconf()
state()

State of the server

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor

clear(resolv_conf, ifname)

Clear all entries in “/etc/resolv.conf” that are associated with the specified interface

clear_all(resolv_conf)

Completely clear out “/etc/resolv.conf”

default_resolvconf_path()

Default resolv.conf path for this system

init(filename)

Invoked when the server is started. start_link/3 or start/3 will block until it returns

set_domain(resolv_conf, ifname, domain)

Set the search domain for non fully qualified domain name lookups

set_nameservers(resolv_conf, ifname, servers)

Set the nameservers that were configured on this interface. These will be added to “/etc/resolv.conf” and replace any entries that were previously added for the specified interface

setup(resolv_conf, ifname, options)

Set all of the options for this interface in one shot. The following options are available

start_link(resolvconf_path \\ "/etc/resolv.conf", opts \\ [])

Start the resolv.conf manager

Link to this section Types

Link to this type ifmap() 
ifmap() :: %{
  domain: String.t(),
  nameservers: [Nerves.Network.Types.ip_address()]
}

Settings for resolvconf

Link to this type resolvconf() 
resolvconf() :: GenServer.server()
Link to this type state() 
state() :: %{ifname: Nerves.Network.Types.ifname(), ifmap: ifmap()}

State of the server.

Link to this section Functions

Link to this function child_spec(init_arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

Link to this function clear(resolv_conf, ifname) 
clear(resolvconf(), Nerves.Network.Types.ifname()) :: :ok

Clear all entries in “/etc/resolv.conf” that are associated with the specified interface.

Link to this function clear_all(resolv_conf) 
clear_all(resolvconf()) :: :ok

Completely clear out “/etc/resolv.conf”.

Link to this function default_resolvconf_path() 
default_resolvconf_path() :: Path.t()

Default resolv.conf path for this system.

Link to this function init(filename)

Invoked when the server is started. start_link/3 or start/3 will block until it returns.

init_arg is the argument term (second argument) passed to start_link/3.

Returning {:ok, state} will cause start_link/3 to return {:ok, pid} and the process to enter its loop.

Returning {:ok, state, timeout} is similar to {:ok, state} except handle_info(:timeout, state) will be called after timeout milliseconds if no messages are received within the timeout.

Returning {:ok, state, :hibernate} is similar to {:ok, state} except the process is hibernated before entering the loop. See c:handle_call/3 for more information on hibernation.

Returning {:ok, state, {:continue, continue}} is similar to {:ok, state} except that immediately after entering the loop the c:handle_continue/2 callback will be invoked with the value continue as first argument.

Returning :ignore will cause start_link/3 to return :ignore and the process will exit normally without entering the loop or calling c:terminate/2. If used when part of a supervision tree the parent supervisor will not fail to start nor immediately try to restart the GenServer. The remainder of the supervision tree will be started and so the GenServer should not be required by other processes. It can be started later with Supervisor.restart_child/2 as the child specification is saved in the parent supervisor. The main use cases for this are:

  • The GenServer is disabled by configuration but might be enabled later.
  • An error occurred and it will be handled by a different mechanism than the Supervisor. Likely this approach involves calling Supervisor.restart_child/2 after a delay to attempt a restart.

Returning {:stop, reason} will cause start_link/3 to return {:error, reason} and the process to exit with reason reason without entering the loop or calling c:terminate/2.

Callback implementation for GenServer.init/1.

Link to this function set_domain(resolv_conf, ifname, domain) 
set_domain(resolvconf(), Nerves.Network.Types.ifname(), String.t()) :: :ok

Set the search domain for non fully qualified domain name lookups.

Link to this function set_nameservers(resolv_conf, ifname, servers) 
set_nameservers(resolvconf(), Nerves.Network.Types.ifname(), [
  Nerves.Network.Types.ip_address()
]) :: :ok

Set the nameservers that were configured on this interface. These will be added to “/etc/resolv.conf” and replace any entries that were previously added for the specified interface.

Link to this function setup(resolv_conf, ifname, options) 
setup(
  resolvconf(),
  Nerves.Network.Types.ifname(),
  Nerves.Network.setup_settings() | Nerves.Network.Types.udhcp_info()
) :: :ok

Set all of the options for this interface in one shot. The following options are available:

  • :domain - the local domain name
  • :nameservers - a list of IP addresses of name servers

Options can be specified either as a keyword list or as a map. E.g.,

%{domain: “example.com”, nameservers: [“8.8.8.8”, “8.8.4.4”]}

Link to this function start_link(resolvconf_path \\ "/etc/resolv.conf", opts \\ []) 
start_link(Path.t(), GenServer.options()) :: GenServer.on_start()

Start the resolv.conf manager.