socket_dist: add listen/2 with opts map

Add listen/2 accepting a generic options map instead of a raw port
number, making the interface transport-agnostic per dist module
convention. Port range iteration (dist_listen_min/dist_listen_max)
is now handled inside socket_dist rather than net_kernel.

Signed-off-by: Peter M <petermm@gmail.com>

Author: petermm

libs/estdlib/src/net_kernel.erl

@@ -211,16 +211,14 @@ init(Options) ->
     process_flag(trap_exit, true),
     LongNames = maps:get(name_domain, Options, longnames) =:= longnames,
     ProtoDist = maps:get(proto_dist, Options, socket_dist),
-    DistPortMin = maps:get(dist_listen_min, Options, 0),
-    DistPortMax = maps:get(dist_listen_max, Options, 0),
+    ListenOpts = maps:with([dist_listen_min, dist_listen_max], Options),
     Name = maps:get(name, Options),
     Node = maps:get(node, Options),
     Cookie = crypto:strong_rand_bytes(16),
     TickInterval = (?NET_TICK_TIME * 1000) div ?NET_TICK_INTENSITY,
     Self = self(),
     Ticker = spawn_link(fun() -> ticker(Self, TickInterval) end),
-    % Try ports in range until one succeeds
-    case try_listen_ports(ProtoDist, Name, DistPortMin, DistPortMax) of
+    case ProtoDist:listen(Name, ListenOpts) of
         {ok, {Listen, _Address, Creation}} ->
             true = erlang:setnode(Node, Creation),
             AcceptPid = ProtoDist:accept(Listen),
@@ -239,18 +237,6 @@ init(Options) ->
             {stop, Reason}
     end.
 
-%% @hidden
-try_listen_ports(ProtoDist, Name, DistPortMin, DistPortMax) ->
-    try_listen_ports(ProtoDist, Name, DistPortMin, DistPortMax, DistPortMin).
-
-try_listen_ports(_ProtoDist, _Name, _DistPortMin, DistPortMax, Port) when Port > DistPortMax ->
-    {error, no_port_available};
-try_listen_ports(ProtoDist, Name, DistPortMin, DistPortMax, Port) ->
-    case ProtoDist:listen(Name, Port) of
-        {ok, _} = Success -> Success;
-        {error, _} -> try_listen_ports(ProtoDist, Name, DistPortMin, DistPortMax, Port + 1)
-    end.
-
 %% @hidden
 handle_call(get_state, _From, #state{longnames = Longnames} = State) ->
     NameDomain =

libs/estdlib/src/socket_dist.erl

@@ -38,19 +38,30 @@
 
 -spec listen(string()) -> {ok, {any(), #net_address{}, pos_integer()}} | {error, any()}.
 listen(Name) ->
-    listen(Name, 0).
+    listen(Name, #{}).
 
--spec listen(string(), non_neg_integer()) ->
+-spec listen(string(), map()) ->
     {ok, {any(), #net_address{}, pos_integer()}} | {error, any()}.
-listen(Name, SocketPort) ->
+listen(Name, Opts) ->
+    PortMin = maps:get(dist_listen_min, Opts, 0),
+    PortMax = maps:get(dist_listen_max, Opts, 0),
+    try_listen_port(Name, PortMin, PortMax).
+
+try_listen_port(_Name, Port, PortMax) when Port > PortMax ->
+    {error, no_port_available};
+try_listen_port(Name, Port, PortMax) ->
+    case do_listen(Name, Port) of
+        {ok, _} = Ok -> Ok;
+        {error, _} when Port < PortMax -> try_listen_port(Name, Port + 1, PortMax);
+        {error, _} = Error -> Error
+    end.
+
+do_listen(Name, SocketPort) ->
     case socket:open(inet, stream, tcp) of
         {ok, LSock} ->
-            try do_listen(Name, LSock, SocketPort) of
-                {ok, _} = Ok ->
-                    Ok;
-                Error ->
-                    socket:close(LSock),
-                    Error
+            try do_listen_bind(Name, LSock, SocketPort) of
+                {ok, _} = Ok -> Ok;
+                Error -> socket:close(LSock), Error
             catch
                 Class:Reason:Stack ->
                     socket:close(LSock),
@@ -60,7 +71,7 @@ listen(Name, SocketPort) ->
             Error
     end.
 
-do_listen(Name, LSock, SocketPort) ->
+do_listen_bind(Name, LSock, SocketPort) ->
     case socket:bind(LSock, #{family => inet, port => SocketPort, addr => {0, 0, 0, 0}}) of
         ok -> do_listen_bound(Name, LSock);
         {error, _} = Error -> Error