PoC for dist min max

Needs handling of port collision and probably use random instead of sequential.

Author: petermm

libs/estdlib/src/net_kernel.erl

@@ -64,6 +64,9 @@
 -define(SETUPTIME, 7000).
 -define(NET_TICK_INTENSITY, 4).
 -define(NET_TICK_TIME, 60).
+% Define distribution port range
+-define(DIST_PORT_MIN, 5001).
+-define(DIST_PORT_MAX, 5003).
 
 %%-----------------------------------------------------------------------------
 %% @doc Start erlang distribution
@@ -179,7 +182,9 @@ init(Options) ->
     TickInterval = (?NET_TICK_TIME * 1000) div ?NET_TICK_INTENSITY,
     Self = self(),
     Ticker = spawn_link(fun() -> ticker(Self, TickInterval) end),
-    case ProtoDist:listen(Name) of
+    %-    case ProtoDist:listen(Name) of
+    % Try ports in range until one succeeds
+    case try_listen_ports(ProtoDist, Name) of
         {ok, {Listen, _Address, Creation}} ->
             true = erlang:setnode(Node, Creation),
             AcceptPid = ProtoDist:accept(Listen),
@@ -198,6 +203,18 @@ init(Options) ->
             {stop, Reason}
     end.
 
+% Add new function to try ports in range
+try_listen_ports(ProtoDist, Name) ->
+    try_listen_ports(ProtoDist, Name, ?DIST_PORT_MIN).
+
+try_listen_ports(_ProtoDist, _Name, Port) when Port > ?DIST_PORT_MAX ->
+    {error, no_port_available};
+try_listen_ports(ProtoDist, Name, Port) ->
+    case ProtoDist:listen(Name, Port) of
+        {ok, _} = Success -> Success;
+        {error, _} -> try_listen_ports(ProtoDist, Name, Port + 1)
+    end.
+
 %% @hidden
 handle_call(get_state, _From, #state{longnames = Longnames} = State) ->
     NameDomain =

libs/estdlib/src/socket_dist.erl

@@ -22,6 +22,8 @@
 % dist interface
 -export([
     listen/1,
+    % Add new export
+    listen/2,
     accept/1,
     accept_connection/5,
     setup/5,
@@ -37,10 +39,15 @@
 
 -spec listen(string()) -> {ok, {any(), #net_address{}, pos_integer()}} | {error, any()}.
 listen(Name) ->
+    listen(Name, 0).
+
+-spec listen(string(), non_neg_integer()) ->
+    {ok, {any(), #net_address{}, pos_integer()}} | {error, any()}.
+listen(Name, Port) ->
     {ok, LSock} = socket:open(inet, stream, tcp),
     ok = socket:bind(LSock, #{
         family => inet,
-        port => 0,
+        port => Port,
         addr => {0, 0, 0, 0}
     }),
     ok = socket:listen(LSock),