DNS
DNS library for Elixir.
Currently, the package provides:
- Elixir structs to interface with
:inet_dnsmodule DNS.Serverbehavior- DNS client
Note: the :inet_dns module is considered internal to Erlang and subject to
change. If this happened this library will be updated to accommodate for that,
but for now :inet_dns is simple and worked for me.
Installation
Make sure you have the Erlang/OTP source files installed, otherwise the
compilation will fail with an {:error, :enoent} message. On Ubuntu, this can
be done using apt-get install erlang-src.
Add :dns to your list of dependencies in mix.exs:
def deps do
[
{:dns, "~> 2.4.0"}
]
endUsage
DNS client
iex> DNS.resolve("google.com")
{:ok, [{216, 58, 221, 110}]}
iex> DNS.resolve("notfound.domain")
{:error, :not_found}
iex> DNS.query("google.com")
%DNS.Record{anlist: [%DNS.Resource{bm: [], class: :in, cnt: 0,
data: {216, 58, 221, 110}, domain: 'google.com', func: false, tm: :undefined,
ttl: 129, type: :a}], arlist: [],
header: %DNS.Header{aa: false, id: 0, opcode: :query, pr: false, qr: true,
ra: true, rcode: 0, rd: false, tc: false}, nslist: [],
qdlist: [%DNS.Query{class: :in, domain: 'google.com', type: :a}]}
iex> DNS.resolve("google.com", :a, {"8.8.8.8", 53})
...DNS server
defmodule ServerExample do
@moduledoc """
Example implementing DNS.Server behaviour
"""
@behaviour DNS.Server
use DNS.Server
def handle(record, _cl) do
Logger.info(fn -> "#{inspect(record)}" end)
query = hd(record.qdlist)
result =
case query.type do
:a -> {127, 0, 0, 1}
:cname -> 'your.domain.com'
:txt -> ['your txt value']
_ -> nil
end
resource = %DNS.Resource{
domain: query.domain,
class: query.class,
type: query.type,
ttl: 0,
data: result
}
%{record | anlist: [resource], header: %{record.header | qr: true}}
end
endTo run the example server in iex:
iex> c "example/test_server.ex"
[ServerExample]
iex> {:ok, server_pid} = ServerExample.start_link 8000
Server listening at 8000
{:ok, #PID<0.180.0>}
iex> Process.exit(server_pid, :normal)
Copyright and License
Copyright (c) 2016-2022 Tung Dao and contributors.
This library is released under the BSD 3-Clause "New" or "Revised" License. See the LICENSE.md file for further details.