117 lines
4.3 KiB
Erlang
117 lines
4.3 KiB
Erlang
%%%-------------------------------------------------------------------
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%%% @author anlicheng
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%%% @copyright (C) 2026, <COMPANY>
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%%% @doc
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%%%
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%%% @end
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%%% Created : 22. 1月 2026 16:01
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%%%-------------------------------------------------------------------
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-module(sdlan_stun_peer_assist).
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-author("anlicheng").
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-behaviour(gen_server).
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%% API
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-export([start_link/0]).
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-export([stun_relay/3]).
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%% gen_server callbacks
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-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
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-define(SERVER, ?MODULE).
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-record(state, {
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socket :: inet:socket(),
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assist_ip :: inet:ip4_address(),
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assist_port :: integer()
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}).
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%%%===================================================================
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%%% API
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%%%===================================================================
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-spec stun_relay(Ip :: inet:ip_address(), Port :: integer(), Reply :: binary()) -> no_return().
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stun_relay(Ip, Port, Reply) when is_integer(Port), is_binary(Reply) ->
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gen_server:cast(?SERVER, {stun_relay, Ip, Port, Reply}).
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%% @doc Spawns the server and registers the local name (unique)
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-spec(start_link() ->
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{ok, Pid :: pid()} | ignore | {error, Reason :: term()}).
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start_link() ->
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gen_server:start_link({local, ?SERVER}, ?MODULE, [], []).
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%%%===================================================================
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%%% gen_server callbacks
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%%%===================================================================
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%% @private
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%% @doc Initializes the server
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-spec(init(Args :: term()) ->
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{ok, State :: #state{}} | {ok, State :: #state{}, timeout() | hibernate} |
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{stop, Reason :: term()} | ignore).
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init([]) ->
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{ok, Props} = application:get_env(sdlan, stun_peer_assist),
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AssistIp = proplists:get_value(ip, Props),
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AssistPort = proplists:get_value(port, Props),
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Opts = [binary, {reuseaddr, true}],
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{ok, Socket} = gen_udp:open(0, Opts),
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inet_udp:controlling_process(Socket, self()),
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logger:debug("[sdlan_stun_peer_assist] started"),
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{ok, #state{socket = Socket, assist_ip = AssistIp, assist_port = AssistPort}}.
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%% @private
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%% @doc Handling call messages
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-spec(handle_call(Request :: term(), From :: {pid(), Tag :: term()},
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State :: #state{}) ->
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{reply, Reply :: term(), NewState :: #state{}} |
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{reply, Reply :: term(), NewState :: #state{}, timeout() | hibernate} |
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{noreply, NewState :: #state{}} |
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{noreply, NewState :: #state{}, timeout() | hibernate} |
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{stop, Reason :: term(), Reply :: term(), NewState :: #state{}} |
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{stop, Reason :: term(), NewState :: #state{}}).
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handle_call(_Request, _From, State = #state{}) ->
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{reply, ok, State}.
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%% @private
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%% @doc Handling cast messages
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-spec(handle_cast(Request :: term(), State :: #state{}) ->
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{noreply, NewState :: #state{}} |
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{noreply, NewState :: #state{}, timeout() | hibernate} |
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{stop, Reason :: term(), NewState :: #state{}}).
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handle_cast({stun_relay, _Ip = {Ip0, Ip1, Ip2, Ip3}, Port, Reply}, State = #state{socket = Sock, assist_ip = AssistIp, assist_port = AssistPort}) ->
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Packet = <<Ip0, Ip1, Ip2, Ip3, Port:16, Reply/binary>>,
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ok = gen_udp:send(Sock, AssistIp, AssistPort, Packet),
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{noreply, State}.
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%% @private
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%% @doc Handling all non call/cast messages
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-spec(handle_info(Info :: timeout() | term(), State :: #state{}) ->
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{noreply, NewState :: #state{}} |
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{noreply, NewState :: #state{}, timeout() | hibernate} |
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{stop, Reason :: term(), NewState :: #state{}}).
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handle_info(_Info, State = #state{}) ->
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{noreply, State}.
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%% @private
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%% @doc This function is called by a gen_server when it is about to
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%% terminate. It should be the opposite of Module:init/1 and do any
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%% necessary cleaning up. When it returns, the gen_server terminates
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%% with Reason. The return value is ignored.
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-spec(terminate(Reason :: (normal | shutdown | {shutdown, term()} | term()),
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State :: #state{}) -> term()).
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terminate(_Reason, _State = #state{}) ->
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ok.
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%% @private
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%% @doc Convert process state when code is changed
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-spec(code_change(OldVsn :: term() | {down, term()}, State :: #state{},
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Extra :: term()) ->
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{ok, NewState :: #state{}} | {error, Reason :: term()}).
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code_change(_OldVsn, State = #state{}, _Extra) ->
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{ok, State}.
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%%%===================================================================
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%%% Internal functions
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%%%===================================================================
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