iot_cloud/apps/iot/src/transport/udp_server.erl
2026-05-30 15:25:40 +08:00

142 lines
5.3 KiB
Erlang

%%%-------------------------------------------------------------------
%%% @author anlicheng
%%% @copyright (C) 2026, <COMPANY>
%%% @doc
%%%
%%% @end
%%% Created : 09. 5月 2026 18:02
%%%-------------------------------------------------------------------
-module(udp_server).
-author("anlicheng").
-behaviour(gen_server).
-define(HEARTBEAT_VERSION, 1).
-define(HEARTBEAT_NONCE_BYTES, 16).
-define(HEARTBEAT_MAC_BYTES, 32).
%% API
-export([start_link/0]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
-define(SERVER, ?MODULE).
-record(state, {
socket :: gen_udp:socket()
}).
%%%===================================================================
%%% API
%%%===================================================================
%% @doc Spawns the server and registers the local name (unique)
-spec(start_link() ->
{ok, Pid :: pid()} | ignore | {error, Reason :: term()}).
start_link() ->
gen_server:start_link({local, ?SERVER}, ?MODULE, [], []).
%%%===================================================================
%%% gen_server callbacks
%%%===================================================================
%% @private
%% @doc Initializes the server
-spec(init(Args :: term()) ->
{ok, State :: #state{}} | {ok, State :: #state{}, timeout() | hibernate} |
{stop, Reason :: term()} | ignore).
init([]) ->
ok = iot_log:set_metadata(),
{ok, UdpServerProps} = application:get_env(iot, udp_server),
Port = proplists:get_value(port, UdpServerProps),
logger:debug("[udp_server] start at port: ~p", [Port]),
{ok, Socket} = gen_udp:open(Port, [binary, {active, true}]),
{ok, #state{socket = Socket}}.
%% @private
%% @doc Handling call messages
-spec(handle_call(Request :: term(), From :: {pid(), Tag :: term()},
State :: #state{}) ->
{reply, Reply :: term(), NewState :: #state{}} |
{reply, Reply :: term(), NewState :: #state{}, timeout() | hibernate} |
{noreply, NewState :: #state{}} |
{noreply, NewState :: #state{}, timeout() | hibernate} |
{stop, Reason :: term(), Reply :: term(), NewState :: #state{}} |
{stop, Reason :: term(), NewState :: #state{}}).
handle_call(_Request, _From, State = #state{}) ->
{reply, ok, State}.
%% @private
%% @doc Handling cast messages
-spec(handle_cast(Request :: term(), State :: #state{}) ->
{noreply, NewState :: #state{}} |
{noreply, NewState :: #state{}, timeout() | hibernate} |
{stop, Reason :: term(), NewState :: #state{}}).
handle_cast(_Request, State = #state{}) ->
{noreply, State}.
%% @private
%% @doc Handling all non call/cast messages
-spec(handle_info(Info :: timeout() | term(), State :: #state{}) ->
{noreply, NewState :: #state{}} |
{noreply, NewState :: #state{}, timeout() | hibernate} |
{stop, Reason :: term(), NewState :: #state{}}).
handle_info({udp, Socket, Ip, Port, Packet}, State = #state{socket = Socket}) ->
handle_heartbeat_packet(Packet, {Ip, Port}),
{noreply, State};
handle_info(Info, State = #state{}) ->
logger:warning("[udp_server] ignore unknown info: ~p", [Info]),
{noreply, State}.
%% @private
%% @doc This function is called by a gen_server when it is about to
%% terminate. It should be the opposite of Module:init/1 and do any
%% necessary cleaning up. When it returns, the gen_server terminates
%% with Reason. The return value is ignored.
-spec(terminate(Reason :: (normal | shutdown | {shutdown, term()} | term()),
State :: #state{}) -> term()).
terminate(_Reason, _State = #state{socket = Socket}) ->
gen_udp:close(Socket),
ok.
%% @private
%% @doc Convert process state when code is changed
-spec(code_change(OldVsn :: term() | {down, term()}, State :: #state{},
Extra :: term()) ->
{ok, NewState :: #state{}} | {error, Reason :: term()}).
code_change(_OldVsn, State = #state{}, _Extra) ->
{ok, State}.
%%%===================================================================
%%% Internal functions
%%%===================================================================
-spec handle_heartbeat_packet(binary(), term()) -> ok.
handle_heartbeat_packet(Packet, Peer) when is_binary(Packet) ->
case decode_heartbeat_packet(Packet) of
{ok, UUID, Timestamp, Payload, Mac} ->
case efka_client_store:verify_heartbeat(UUID, Timestamp, Payload, Mac) of
true ->
Pid = iot_host:get_pid(UUID),
iot_host:heartbeat(Pid);
false ->
logger:warning("[udp_server] ignore invalid heartbeat auth from peer: ~p, uuid: ~p", [Peer, UUID]),
ok
end;
error ->
logger:warning("[udp_server] ignore invalid heartbeat packet from peer: ~p, packet: ~p", [Peer, Packet]),
ok
end.
-spec decode_heartbeat_packet(binary()) ->
{ok, UUID :: binary(), Timestamp :: integer(), Payload :: binary(), Mac :: binary()} | error.
decode_heartbeat_packet(Packet = <<?HEARTBEAT_VERSION:8, UUIDLen:16, UUID:UUIDLen/binary,
Timestamp:64/unsigned-big, _Nonce:?HEARTBEAT_NONCE_BYTES/binary, _Mac:?HEARTBEAT_MAC_BYTES/binary>>)
when UUIDLen > 0 ->
PayloadSize = byte_size(Packet) - ?HEARTBEAT_MAC_BYTES,
<<Payload:PayloadSize/binary, Mac:?HEARTBEAT_MAC_BYTES/binary>> = Packet,
{ok, UUID, Timestamp, Payload, Mac};
decode_heartbeat_packet(_Packet) ->
error.