Merge c480887d16 into c93be153e6

farmbot_os/config/target/dev.exs

@@ -10,22 +10,7 @@ config :vintage_net,
   persistence: VintageNet.Persistence.Null,
   config: [
     {"wlan0", %{type: VintageNet.Technology.Null}},
-    {"usb0",
-     %{
-       type: FarmbotOS.Platform.Target.Configurator.CaptivePortal,
-       ipv4: %{
-         method: :static,
-         address: "192.168.25.1",
-         netmask: "255.255.255.0"
-       },
-       dnsmasq: %{
-         domain: "farmbot",
-         server: "192.168.25.1",
-         address: "192.168.25.1",
-         start: "192.168.25.2",
-         end: "192.168.25.10"
-       }
-     }}
+    {"usb0", %{type: VintageNetDirect}}
   ]
 
 config :mdns_lite,

farmbot_os/config/target/prod.exs

@@ -10,22 +10,7 @@ config :vintage_net,
   persistence: VintageNet.Persistence.Null,
   config: [
     {"wlan0", %{type: VintageNet.Technology.Null}},
-    {"usb0",
-     %{
-       type: FarmbotOS.Platform.Target.Configurator.CaptivePortal,
-       ipv4: %{
-         method: :static,
-         address: "192.168.25.1",
-         netmask: "255.255.255.0"
-       },
-       dnsmasq: %{
-         domain: "farmbot",
-         server: "192.168.25.1",
-         address: "192.168.25.1",
-         start: "192.168.25.2",
-         end: "192.168.25.10"
-       }
-     }}
+    {"usb0", %{type: VintageNetDirect}}
   ]
 
 config :mdns_lite,

farmbot_os/lib/farmbot_os/configurator/captive_dns.ex

@@ -0,0 +1,79 @@
+defmodule FarmbotOS.Configurator.CaptiveDNS do
+  use GenServer
+  alias __MODULE__, as: State
+
+  defstruct [:dns_socket, :dns_port, :ifname]
+
+  def start_link(ifname, port) do
+    GenServer.start_link(__MODULE__, [ifname, port])
+  end
+
+  @impl GenServer
+  def init([ifname, port]) do
+    send(self(), :open_dns)
+    # use charlist here because :inet module works with charlists
+    {:ok, %State{dns_port: port, ifname: to_charlist(ifname)}}
+  end
+
+  @impl GenServer
+  # open a UDP socket on port 53
+  def handle_info(:open_dns, state) do
+    case :gen_udp.open(state.dns_port, [:binary, active: true, reuseaddr: true]) do
+      {:ok, socket} ->
+        {:noreply, %State{state | dns_socket: socket}}
+
+      error ->
+        {:stop, error, state}
+    end
+  end
+
+  # binary dns message from the socket
+  def handle_info(
+        {:udp, socket, ip, port, packet},
+        %{dns_socket: socket} = state
+      ) do
+    record = DNS.Record.decode(packet)
+    {answers, state} = handle_dns(record.qdlist, [], state)
+    response = DNS.Record.encode(%{record | anlist: answers})
+    _ = :gen_udp.send(socket, ip, port, response)
+    {:noreply, state}
+  end
+
+  # recursively check for dns queries, respond to each of them with the local ip address.
+
+  # respond to `a` with our current ip address
+  defp handle_dns(
+         [%{type: :a} = q | rest],
+         answers,
+         state
+       ) do
+    ifname = state.ifname
+    {:ok, interfaces} = :inet.getifaddrs()
+    {^ifname, ifinfo} = List.keyfind(interfaces, ifname, 0)
+
+    addr =
+      Enum.find_value(ifinfo, fn
+        {:addr, {_, _, _, _} = ipv4_addr} -> ipv4_addr
+        _ -> false
+      end)
+
+    answer = make_record(q.domain, q.type, 120, addr)
+    handle_dns(rest, [answer | answers], state)
+  end
+
+  # stop recursing when qdlist is fully enumerated
+  defp handle_dns([], answers, state) do
+    {Enum.reverse(answers), state}
+  end
+
+  defp make_record(domain, type, ttl, data) do
+    %DNS.Resource{
+      domain: domain,
+      class: :in,
+      type: type,
+      ttl: ttl,
+      data: data
+    }
+  end
+end
+FarmbotOS.Configurator.CaptiveDNS.start_link("lo0", 4040)

farmbot_os/mix.exs

@@ -92,6 +92,7 @@ defmodule FarmbotOS.MixProject do
       {:cors_plug, "~> 2.0"},
       {:plug_cowboy, "~> 2.1"},
       {:phoenix_html, "~> 2.13"},
+      {:dns, "~> 2.1"},
 
       # Nerves stuff.
       {:nerves, "~> 1.5", runtime: false},

farmbot_os/platform/target/configurator/captive_portal.ex

@@ -6,6 +6,7 @@ defmodule FarmbotOS.Platform.Target.Configurator.CaptivePortal do
 
   @behaviour VintageNet.Technology
   require FarmbotCore.Logger
+  alias FarmbotOS.Configurator.CaptiveDNS
 
   @impl VintageNet.Technology
   def normalize(%{vintage_net_wifi: _} = config) do
@@ -24,7 +25,7 @@ defmodule FarmbotOS.Platform.Target.Configurator.CaptivePortal do
 
     ifname
     |> vintage_wifi(normalized, opts)
-    |> dnsmasq(opts)
+    |> add_captive_dns()
   end
 
   def to_raw_config(ifname, config, opts) do
@@ -32,7 +33,7 @@ defmodule FarmbotOS.Platform.Target.Configurator.CaptivePortal do
 
     ifname
     |> vintage_ethernet(normalized, opts)
-    |> dnsmasq(opts)
+    |> add_captive_dns()
   end
 
   @impl VintageNet.Technology
@@ -45,67 +46,12 @@ defmodule FarmbotOS.Platform.Target.Configurator.CaptivePortal do
     VintageNetWiFi.ioctl(ifname, ioctl, args)
   end
 
-  defp dnsmasq(
-         %{ifname: ifname, source_config: %{dnsmasq: config}} = raw_config,
-         opts
-       ) do
-    tmpdir = Keyword.fetch!(opts, :tmpdir)
-    killall = Keyword.fetch!(opts, :bin_killall)
-    dnsmasq = System.find_executable("dnsmasq")
-    dnsmasq_conf_path = Path.join(tmpdir, "dnsmasq.conf.#{ifname}")
-    dnsmasq_lease_file = Path.join(tmpdir, "dnsmasq.leases.#{ifname}")
-    dnsmasq_pid_file = Path.join(tmpdir, "dnsmasq.pid.#{ifname}")
-
-    dnsmasq_conf_contents = """
-    interface=#{ifname}
-    except-interface=lo
-    localise-queries
-    bogus-priv
-    bind-interfaces
-    listen-address=#{config[:address]}
-    server=#{config[:address]}
-    address=/#/#{config[:address]}
-    dhcp-option=6,#{config[:address]}
-    dhcp-range=#{config[:start]},#{config[:end]},12h
-    """
-
-    files = [
-      {dnsmasq_conf_path, dnsmasq_conf_contents}
+  defp add_captive_dns(%{ifname: ifname} = raw_config) do
+    child_specs = [
+      {CaptiveDNS, [ifname, 53]}
     ]
 
-    up_cmds = [
-      {:run, dnsmasq,
-       [
-         "-K",
-         "-l",
-         dnsmasq_lease_file,
-         "-x",
-         dnsmasq_pid_file,
-         "-C",
-         dnsmasq_conf_path
-       ]}
-    ]
-
-    down_cmds = [
-      {:run, killall, ["-q", "-9", "dnsmasq"]}
-    ]
-
-    updated_raw_config = %{
-      raw_config
-      | files: raw_config.files ++ files,
-        up_cmds: raw_config.up_cmds ++ up_cmds,
-        down_cmds: raw_config.down_cmds ++ down_cmds,
-        cleanup_files:
-          raw_config.cleanup_files ++
-            [dnsmasq_conf_path, dnsmasq_lease_file, dnsmasq_pid_file]
-    }
-
-    updated_raw_config
-  end
-
-  defp dnsmasq(%{} = raw_config, _opts) do
-    FarmbotCore.Logger.error(1, "DNSMASQ Disabled")
-    raw_config
+    %{raw_config | child_specs: raw_config.child_specs ++ child_specs}
   end
 
   defp vintage_wifi(ifname, config, opts) do

farmbot_os/platform/target/network.ex

@@ -36,10 +36,7 @@ defmodule FarmbotOS.Platform.Target.Network do
         address: "192.168.24.1",
         netmask: "255.255.255.0"
       },
-      dnsmasq: %{
-        domain: "farmbot",
-        server: "192.168.24.1",
-        address: "192.168.24.1",
+      dhcpd: %{
         start: "192.168.24.2",
         end: "192.168.24.10"
       }

farmbot_os/test/farmbot_os/captive_dns_test.exs

@@ -0,0 +1,13 @@
+defmodule FarmbotOS.Configurator.CaptiveDNSTest do
+  use ExUnit.Case, async: false
+
+  @dig System.find_executable("dig")
+  if @dig do
+    test "all dns queries resolve to local ip address" do
+      {:ok, dns_server} = FarmbotOS.Configurator.CaptiveDNS.start_link("lo0", 4040)
+      res = :os.cmd('dig -p 4040')
+      refute String.contains?(to_string(res), "no servers could be reached")
+    end
+  end
+
+end