Remove MQTT processor field peer_addr

as it seems to always match peer_host.

Commit 7e09b85426959883c2cbe5f409aeaa299427fd8e adds peer address
provided by WebMQTT plugin.

However, this seems unnecessary since function rabbit_net:peername/1 on
the unwrapped socket provides the same address.

The peer address was the address of the proxy if the proxy protocol is
enabled.

This commit simplifies code and reduces memory consumption.

3 files changed, 35 insertions, 36 deletions

diff --git a/deps/rabbitmq_mqtt/src/rabbit_mqtt_processor.erl b/deps/rabbitmq_mqtt/src/rabbit_mqtt_processor.erl
index 58bccaa2f5..952b26e961 100644
--- a/deps/rabbitmq_mqtt/src/rabbit_mqtt_processor.erl
+++ b/deps/rabbitmq_mqtt/src/rabbit_mqtt_processor.erl
@@ -8,7 +8,7 @@
 %% This module contains code that is common to MQTT and Web MQTT connections.
 -module(rabbit_mqtt_processor).
 
--export([info/2, initial_state/2, initial_state/4,
+-export([info/2, initial_state/2, initial_state/3,
          process_packet/2, serialise/2,
          terminate/4, handle_pre_hibernate/0,
          handle_ra_event/2, handle_down/2, handle_queue_event/2,
@@ -21,7 +21,8 @@
 -export_type([state/0]).
 
 -import(rabbit_mqtt_util, [mqtt_to_amqp/1,
-                           amqp_to_mqtt/1]).
+                           amqp_to_mqtt/1,
+                           ip_address_to_binary/1]).
 
 -include_lib("kernel/include/logger.hrl").
 -include_lib("rabbit_common/include/rabbit.hrl").
@@ -57,7 +58,6 @@
          prefetch :: non_neg_integer(),
          client_id :: option(binary()),
          conn_name :: option(binary()),
-         peer_addr :: inet:ip_address(),
          host :: inet:ip_address(),
          port :: inet:port_number(),
          peer_host :: inet:ip_address(),
@@ -87,21 +87,19 @@
 
 -opaque state() :: #state{}.
 
--spec initial_state(Socket :: any(), ConnectionName :: binary()) ->
+-spec initial_state(Socket :: rabbit_net:socket(),
+                    ConnectionName :: binary()) ->
     state().
 initial_state(Socket, ConnectionName) ->
-    {ok, {PeerAddr, _PeerPort}} = rabbit_net:peername(Socket),
     initial_state(Socket,
                   ConnectionName,
-                  fun serialise_and_send_to_client/2,
-                  PeerAddr).
+                  fun serialise_and_send_to_client/2).
 
--spec initial_state(Socket :: any(),
+-spec initial_state(Socket :: rabbit_net:socket(),
                     ConnectionName :: binary(),
-                    SendFun :: fun((mqtt_packet(), state()) -> any()),
-                    PeerAddr :: inet:ip_address()) ->
+                    SendFun :: fun((mqtt_packet(), state()) -> any())) ->
     state().
-initial_state(Socket, ConnectionName, SendFun, PeerAddr) ->
+initial_state(Socket, ConnectionName, SendFun) ->
     Flow = case rabbit_misc:get_env(rabbit, mirroring_flow_control, true) of
                true   -> flow;
                false  -> noflow
@@ -114,7 +112,6 @@ initial_state(Socket, ConnectionName, SendFun, PeerAddr) ->
                       prefetch       = rabbit_mqtt_util:env(prefetch),
                       delivery_flow  = Flow,
                       connected_at   = os:system_time(milli_seconds),
-                      peer_addr      = PeerAddr,
                       peer_host      = PeerHost,
                       peer_port      = PeerPort,
                       host           = Host,
@@ -393,8 +390,8 @@ check_client_id(_) ->
 check_credentials(Packet = #mqtt_packet_connect{username = Username,
                                                 password = Password},
                   State = #state{cfg = #cfg{ssl_login_name = SslLoginName,
-                                            peer_addr = PeerAddr}}) ->
-    Ip = list_to_binary(inet:ntoa(PeerAddr)),
+                                            peer_host = PeerHost}}) ->
+    Ip = ip_address_to_binary(PeerHost),
     case creds(Username, Password, SslLoginName) of
         nocreds ->
             rabbit_core_metrics:auth_attempt_failed(Ip, <<>>, mqtt),
@@ -699,13 +696,15 @@ make_will_msg(#mqtt_packet_connect{will_retain = Retain,
               payload = Msg}.
 
 process_login(_UserBin, _PassBin, ClientId,
-              #state{cfg = #cfg{peer_addr  = Addr},
+              #state{cfg = #cfg{peer_host = PeerHost},
                      auth_state = #auth_state{username = Username,
                                               user = User,
                                               vhost = VHost
                                              }} = State)
   when Username =/= undefined, User =/= undefined, VHost =/= underfined ->
-    rabbit_core_metrics:auth_attempt_failed(list_to_binary(inet:ntoa(Addr)), Username, mqtt),
+    rabbit_core_metrics:auth_attempt_failed(ip_address_to_binary(PeerHost),
+                                            Username,
+                                            mqtt),
     ?LOG_ERROR(
        "MQTT detected duplicate connect attempt for client ID '~ts', user '~ts', vhost '~ts'",
        [ClientId, Username, VHost]),
@@ -714,13 +713,13 @@ process_login(UserBin, PassBin, ClientId,
               #state{auth_state = undefined,
                      cfg = #cfg{socket = Sock,
                                 ssl_login_name = SslLoginName,
-                                peer_addr = Addr
+                                peer_host = PeerHost
                                }} = State0) ->
     {ok, {_PeerHost, _PeerPort, _Host, Port}} = rabbit_net:socket_ends(Sock, inbound),
     {VHostPickedUsing, {VHost, UsernameBin}} = get_vhost(UserBin, SslLoginName, Port),
     ?LOG_DEBUG("MQTT vhost picked using ~s",
                [human_readable_vhost_lookup_strategy(VHostPickedUsing)]),
-    RemoteIpAddressBin = list_to_binary(inet:ntoa(Addr)),
+    Ip = ip_address_to_binary(PeerHost),
     Input = #{vhost => VHost,
               username_bin => UsernameBin,
               pass_bin => PassBin,
@@ -736,10 +735,10 @@ process_login(UserBin, PassBin, ClientId,
            ],
            Input, State0) of
         {ok, _Output, State} ->
-            rabbit_core_metrics:auth_attempt_succeeded(RemoteIpAddressBin, UsernameBin, mqtt),
+            rabbit_core_metrics:auth_attempt_succeeded(Ip, UsernameBin, mqtt),
             {ok, State};
         {error, _ConnectionRefusedReturnCode, _State} = Err ->
-            rabbit_core_metrics:auth_attempt_failed(RemoteIpAddressBin, UsernameBin, mqtt),
+            rabbit_core_metrics:auth_attempt_failed(Ip, UsernameBin, mqtt),
             Err
     end.
 
@@ -837,12 +836,12 @@ check_vhost_access(#{vhost := VHost,
                      client_id := ClientId,
                      user := User = #user{username = Username}
                     } = In,
-                   #state{cfg = #cfg{peer_addr = PeerAddr}} = State) ->
+                   #state{cfg = #cfg{peer_host = PeerHost}} = State) ->
     AuthzCtx = #{<<"client_id">> => ClientId},
     try rabbit_access_control:check_vhost_access(
           User,
           VHost,
-          {ip, PeerAddr},
+          {ip, PeerHost},
           AuthzCtx) of
         ok ->
             {ok, maps:put(authz_ctx, AuthzCtx, In), State}
@@ -859,8 +858,8 @@ check_user_loopback(#{vhost := VHost,
                       user := User,
                       authz_ctx := AuthzCtx
                      },
-                    #state{cfg = #cfg{peer_addr = PeerAddr}} = State) ->
-    case rabbit_access_control:check_user_loopback(UsernameBin, PeerAddr) of
+                    #state{cfg = #cfg{peer_host = PeerHost}} = State) ->
+    case rabbit_access_control:check_user_loopback(UsernameBin, PeerHost) of
         ok ->
             AuthState = #auth_state{user = User,
                                     username = UsernameBin,
@@ -1964,7 +1963,6 @@ format_status(
                   prefetch = Prefetch,
                   client_id = ClientID,
                   conn_name = ConnName,
-                  peer_addr = PeerAddr,
                   host = Host,
                   port = Port,
                   peer_host = PeerHost,
@@ -1986,7 +1984,6 @@ format_status(
             prefetch => Prefetch,
             client_id => ClientID,
             conn_name => ConnName,
-            peer_addr => PeerAddr,
             host => Host,
             port => Port,
             peer_host => PeerHost,
diff --git a/deps/rabbitmq_mqtt/src/rabbit_mqtt_util.erl b/deps/rabbitmq_mqtt/src/rabbit_mqtt_util.erl
index d098d3ff93..75637dc95d 100644
--- a/deps/rabbitmq_mqtt/src/rabbit_mqtt_util.erl
+++ b/deps/rabbitmq_mqtt/src/rabbit_mqtt_util.erl
@@ -23,7 +23,8 @@
          init_sparkplug/0,
          mqtt_to_amqp/1,
          amqp_to_mqtt/1,
-         truncate_binary/2
+         truncate_binary/2,
+         ip_address_to_binary/1
         ]).
 
 -define(MAX_TOPIC_TRANSLATION_CACHE_SIZE, 12).
@@ -209,3 +210,7 @@ truncate_binary(Bin, Size)
 truncate_binary(Bin, Size)
   when is_binary(Bin) ->
     binary:part(Bin, 0, Size).
+
+-spec ip_address_to_binary(inet:ip_address()) -> binary().
+ip_address_to_binary(IpAddress) ->
+    list_to_binary(inet:ntoa(IpAddress)).
diff --git a/deps/rabbitmq_web_mqtt/src/rabbit_web_mqtt_handler.erl b/deps/rabbitmq_web_mqtt/src/rabbit_web_mqtt_handler.erl
index 1fb022ee44..31e823dae3 100644
--- a/deps/rabbitmq_web_mqtt/src/rabbit_web_mqtt_handler.erl
+++ b/deps/rabbitmq_web_mqtt/src/rabbit_web_mqtt_handler.erl
@@ -57,7 +57,7 @@ upgrade(Req, Env, Handler, HandlerState) ->
 upgrade(Req, Env, Handler, HandlerState, Opts) ->
     cowboy_websocket:upgrade(Req, Env, Handler, HandlerState, Opts).
 
-takeover(Parent, Ref, Socket, Transport, Opts, Buffer, {Handler, {HandlerState, PeerAddr}}) ->
+takeover(Parent, Ref, Socket, Transport, Opts, Buffer, {Handler, HandlerState}) ->
     Sock = case HandlerState#state.socket of
                undefined ->
                    Socket;
@@ -65,7 +65,7 @@ takeover(Parent, Ref, Socket, Transport, Opts, Buffer, {Handler, {HandlerState,
                    {rabbit_proxy_socket, Socket, ProxyInfo}
            end,
     cowboy_websocket:takeover(Parent, Ref, Socket, Transport, Opts, Buffer,
-                              {Handler, {HandlerState#state{socket = Sock}, PeerAddr}}).
+                              {Handler, HandlerState#state{socket = Sock}}).
 
 %% cowboy_websocket
 init(Req, Opts) ->
@@ -73,7 +73,6 @@ init(Req, Opts) ->
         undefined ->
             no_supported_sub_protocol(undefined, Req);
         Protocol ->
-            {PeerAddr, _PeerPort} = maps:get(peer, Req),
             WsOpts0 = proplists:get_value(ws_opts, Opts, #{}),
             WsOpts  = maps:merge(#{compress => true}, WsOpts0),
             case lists:member(<<"mqtt">>, Protocol) of
@@ -82,16 +81,15 @@ init(Req, Opts) ->
                 true ->
                     {?MODULE,
                      cowboy_req:set_resp_header(<<"sec-websocket-protocol">>, <<"mqtt">>, Req),
-                     {#state{socket = maps:get(proxy_header, Req, undefined)},
-                      PeerAddr},
+                     #state{socket = maps:get(proxy_header, Req, undefined)},
                      WsOpts}
             end
     end.
 
--spec websocket_init({state(), PeerAddr :: binary()}) ->
+-spec websocket_init(state()) ->
     {cowboy_websocket:commands(), state()} |
     {cowboy_websocket:commands(), state(), hibernate}.
-websocket_init({State0 = #state{socket = Sock}, PeerAddr}) ->
+websocket_init(State0 = #state{socket = Sock}) ->
     logger:set_process_metadata(#{domain => ?RMQLOG_DOMAIN_CONN ++ [web_mqtt]}),
     ok = file_handle_cache:obtain(),
     case rabbit_net:connection_string(Sock, inbound) of
@@ -102,8 +100,7 @@ websocket_init({State0 = #state{socket = Sock}, PeerAddr}) ->
             PState = rabbit_mqtt_processor:initial_state(
                        rabbit_net:unwrap_socket(Sock),
                        ConnName,
-                       fun send_reply/2,
-                       PeerAddr),
+                       fun send_reply/2),
             State1 = State0#state{conn_name = ConnName,
                                   proc_state = PState},
             State = rabbit_event:init_stats_timer(State1, #state.stats_timer),