VPN over Erlang Distribution Protocol

vpwn.erl

-module(vpwn).
-export([start/3]).


start(Node, SrcIP, DstIP) ->
    Pid = peer(Node, SrcIP, DstIP),

    {ok, Dev} = tuncer:create(),    
    ok = tuncer:up(Dev, SrcIP),

    spawn_link(fun() -> read(Dev, Pid) end),
    write(Dev).

% Parent
peer(N, SrcIP, DstIP) when is_atom(N) ->
    pong = net_adm:ping(N),
    Self = self(),
    spawn_link(N, vpwn, start, [Self, DstIP, SrcIP]);
% Child
peer(N, _, _) when is_pid(N) ->
    N.

read(Dev, Pid) ->
    case tuncer:read(Dev, 16#FFFF) of
        {error,eagain} ->
            timer:sleep(10),
            read(Dev, Pid);
        {ok, Data} ->
            Pid ! {data, Data},
            read(Dev, Pid)
    end.

write(Dev) ->
    receive
        {data, Data} ->
            ok = tuncer:write(Dev, Data),
            write(Dev);
        Error ->
            error_logger:error_report([{write_error, Error}])
    end.