Merge 0.9->0.10
[prosody.git] / net / server_event.lua
index 882d10ed95d0e45d3436ed663c73c84258bd4ddb..1329a43d67abc0933f234b3af829763afaf28453 100644 (file)
@@ -11,6 +11,7 @@
                        -- when using luasec, there are 4 cases of timeout errors: wantread or wantwrite during reading or writing
 
 --]]
+-- luacheck: ignore 212/self 431/err 211/ret
 
 local SCRIPT_NAME           = "server_event.lua"
 local SCRIPT_VERSION        = "0.05"
@@ -32,27 +33,32 @@ local cfg = {
        DEBUG                 = true,  -- show debug messages
 }
 
-local function use(x) return rawget(_G, x); end
-local ipairs = use "ipairs"
-local string = use "string"
-local select = use "select"
-local require = use "require"
-local tostring = use "tostring"
-local coroutine = use "coroutine"
-local setmetatable = use "setmetatable"
+local pairs = pairs
+local select = select
+local require = require
+local tostring = tostring
+local setmetatable = setmetatable
 
 local t_insert = table.insert
 local t_concat = table.concat
+local s_sub = string.sub
 
-local ssl = use "ssl"
-local socket = use "socket" or require "socket"
+local coroutine_wrap = coroutine.wrap
+local coroutine_yield = coroutine.yield
+
+local has_luasec, ssl = pcall ( require , "ssl" )
+local socket = require "socket"
+local levent = require "luaevent.core"
+
+local socket_gettime = socket.gettime
+local getaddrinfo = socket.dns.getaddrinfo
 
 local log = require ("util.logger").init("socket")
 
 local function debug(...)
        return log("debug", ("%s "):rep(select('#', ...)), ...)
 end
-local vdebug = debug;
+-- local vdebug = debug;
 
 local bitor = ( function( ) -- thx Rici Lake
        local hasbit = function( x, p )
@@ -72,741 +78,680 @@ local bitor = ( function( ) -- thx Rici Lake
        end
 end )( )
 
-local event = require "luaevent.core"
-local base = event.new( )
-local EV_READ = event.EV_READ
-local EV_WRITE = event.EV_WRITE
-local EV_TIMEOUT = event.EV_TIMEOUT
-local EV_SIGNAL = event.EV_SIGNAL
+local base = levent.new( )
+local addevent = base.addevent
+local EV_READ = levent.EV_READ
+local EV_WRITE = levent.EV_WRITE
+local EV_TIMEOUT = levent.EV_TIMEOUT
+local EV_SIGNAL = levent.EV_SIGNAL
 
 local EV_READWRITE = bitor( EV_READ, EV_WRITE )
 
-local interfacelist = ( function( )  -- holds the interfaces for sockets
-       local array = { }
-       local len = 0
-       return function( method, arg )
-               if "add" == method then
-                       len = len + 1
-                       array[ len ] = arg
-                       arg:_position( len )
-                       return len
-               elseif "delete" == method then
-                       if len <= 0 then
-                               return nil, "array is already empty"
+local interfacelist = { }
+
+-- Client interface methods
+local interface_mt = {}; interface_mt.__index = interface_mt;
+
+-- Private methods
+function interface_mt:_close()
+       return self:_destroy();
+end
+
+function interface_mt:_start_connection(plainssl) -- called from wrapclient
+       local callback = function( event )
+               if EV_TIMEOUT == event then  -- timeout during connection
+                       self.fatalerror = "connection timeout"
+                       self:ontimeout()  -- call timeout listener
+                       self:_close()
+                       debug( "new connection failed. id:", self.id, "error:", self.fatalerror )
+               else
+                       if plainssl and has_luasec then  -- start ssl session
+                               self:starttls(self._sslctx, true)
+                       else  -- normal connection
+                               self:_start_session(true)
                        end
-                       local position = arg:_position()  -- get position in array
-                       if position ~= len then
-                               local interface = array[ len ]  -- get last interface
-                               array[ position ] = interface  -- copy it into free position
-                               array[ len ] = nil  -- free last position
-                               interface:_position( position )  -- set new position in array
-                       else  -- free last position
-                               array[ len ] = nil
+                       debug( "new connection established. id:", self.id )
+               end
+               self.eventconnect = nil
+               return -1
+       end
+       self.eventconnect = addevent( base, self.conn, EV_WRITE, callback, cfg.CONNECT_TIMEOUT )
+       return true
+end
+function interface_mt:_start_session(call_onconnect) -- new session, for example after startssl
+       if self.type == "client" then
+               local callback = function( )
+                       self:_lock( false,  false, false )
+                       --vdebug( "start listening on client socket with id:", self.id )
+                       self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
+                       if call_onconnect then
+                               self:onconnect()
                        end
-                       len = len - 1
-                       return len
-               else
-                       return array
+                       self.eventsession = nil
+                       return -1
                end
+               self.eventsession = addevent( base, nil, EV_TIMEOUT, callback, 0 )
+       else
+               self:_lock( false )
+               --vdebug( "start listening on server socket with id:", self.id )
+               self.eventread = addevent( base, self.conn, EV_READ, self.readcallback )  -- register callback
        end
-end )( )
-
--- Client interface methods
-local interface_mt
-do
-       interface_mt = {}; interface_mt.__index = interface_mt;
-       
-       local addevent = base.addevent
-       local coroutine_wrap, coroutine_yield = coroutine.wrap,coroutine.yield
-       
-       -- Private methods
-       function interface_mt:_position(new_position)
-                       self.position = new_position or self.position
-                       return self.position;
-       end
-       function interface_mt:_close()
-               return self:_destroy();
-       end
-       
-       function interface_mt:_start_connection(plainssl) -- should be called from addclient
-                       local callback = function( event )
-                               if EV_TIMEOUT == event then  -- timeout during connection
-                                       self.fatalerror = "connection timeout"
-                                       self:ontimeout()  -- call timeout listener
-                                       self:_close()
-                                       debug( "new connection failed. id:", self.id, "error:", self.fatalerror )
-                               else
-                                       if plainssl and ssl then  -- start ssl session
-                                               self:starttls(self._sslctx, true)
-                                       else  -- normal connection
-                                               self:_start_session(true)
+       return true
+end
+function interface_mt:_start_ssl(call_onconnect) -- old socket will be destroyed, therefore we have to close read/write events first
+       --vdebug( "starting ssl session with client id:", self.id )
+       local _
+       _ = self.eventread and self.eventread:close( )  -- close events; this must be called outside of the event callbacks!
+       _ = self.eventwrite and self.eventwrite:close( )
+       self.eventread, self.eventwrite = nil, nil
+       local err
+       self.conn, err = ssl.wrap( self.conn, self._sslctx )
+       if err then
+               self.fatalerror = err
+               self.conn = nil  -- cannot be used anymore
+               if call_onconnect then
+                       self.ondisconnect = nil  -- dont call this when client isnt really connected
+               end
+               self:_close()
+               debug( "fatal error while ssl wrapping:", err )
+               return false
+       end
+       self.conn:settimeout( 0 )  -- set non blocking
+       local handshakecallback = coroutine_wrap(function( event )
+               local _, err
+               local attempt = 0
+               local maxattempt = cfg.MAX_HANDSHAKE_ATTEMPTS
+               while attempt < maxattempt do  -- no endless loop
+                       attempt = attempt + 1
+                       debug( "ssl handshake of client with id:"..tostring(self)..", attempt:"..attempt )
+                       if attempt > maxattempt then
+                               self.fatalerror = "max handshake attempts exceeded"
+                       elseif EV_TIMEOUT == event then
+                               self.fatalerror = "timeout during handshake"
+                       else
+                               _, err = self.conn:dohandshake( )
+                               if not err then
+                                       self:_lock( false, false, false )  -- unlock the interface; sending, closing etc allowed
+                                       self.send = self.conn.send  -- caching table lookups with new client object
+                                       self.receive = self.conn.receive
+                                       if not call_onconnect then  -- trigger listener
+                                               self:onstatus("ssl-handshake-complete");
                                        end
-                                       debug( "new connection established. id:", self.id )
+                                       self:_start_session( call_onconnect )
+                                       debug( "ssl handshake done" )
+                                       self.eventhandshake = nil
+                                       return -1
                                end
-                               self.eventconnect = nil
-                               return -1
-                       end
-                       self.eventconnect = addevent( base, self.conn, EV_WRITE, callback, cfg.CONNECT_TIMEOUT )
-                       return true
-       end
-       function interface_mt:_start_session(call_onconnect) -- new session, for example after startssl
-               if self.type == "client" then
-                       local callback = function( )
-                               self:_lock( false,  false, false )
-                               --vdebug( "start listening on client socket with id:", self.id )
-                               self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
-                               if call_onconnect then
-                                       self:onconnect()
+                               if err == "wantwrite" then
+                                       event = EV_WRITE
+                               elseif err == "wantread" then
+                                       event = EV_READ
+                               else
+                                       debug( "ssl handshake error:", err )
+                                       self.fatalerror = err
                                end
-                               self.eventsession = nil
-                               return -1
                        end
-                       self.eventsession = addevent( base, nil, EV_TIMEOUT, callback, 0 )
-               else
-                       self:_lock( false )
-                       --vdebug( "start listening on server socket with id:", self.id )
-                       self.eventread = addevent( base, self.conn, EV_READ, self.readcallback )  -- register callback
-               end
-               return true
-       end
-       function interface_mt:_start_ssl(call_onconnect) -- old socket will be destroyed, therefore we have to close read/write events first
-                       --vdebug( "starting ssl session with client id:", self.id )
-                       local _
-                       _ = self.eventread and self.eventread:close( )  -- close events; this must be called outside of the event callbacks!
-                       _ = self.eventwrite and self.eventwrite:close( )
-                       self.eventread, self.eventwrite = nil, nil
-                       local err
-                       self.conn, err = ssl.wrap( self.conn, self._sslctx )
-                       if err then
-                               self.fatalerror = err
-                               self.conn = nil  -- cannot be used anymore
+                       if self.fatalerror then
                                if call_onconnect then
                                        self.ondisconnect = nil  -- dont call this when client isnt really connected
                                end
                                self:_close()
-                               debug( "fatal error while ssl wrapping:", err )
-                               return false
-                       end
-                       self.conn:settimeout( 0 )  -- set non blocking
-                       local handshakecallback = coroutine_wrap(
-                               function( event )
-                                       local _, err
-                                       local attempt = 0
-                                       local maxattempt = cfg.MAX_HANDSHAKE_ATTEMPTS
-                                       while attempt < maxattempt do  -- no endless loop
-                                               attempt = attempt + 1
-                                               debug( "ssl handshake of client with id:"..tostring(self)..", attempt:"..attempt )
-                                               if attempt > maxattempt then
-                                                       self.fatalerror = "max handshake attempts exceeded"
-                                               elseif EV_TIMEOUT == event then
-                                                       self.fatalerror = "timeout during handshake"
-                                               else
-                                                       _, err = self.conn:dohandshake( )
-                                                       if not err then
-                                                               self:_lock( false, false, false )  -- unlock the interface; sending, closing etc allowed
-                                                               self.send = self.conn.send  -- caching table lookups with new client object
-                                                               self.receive = self.conn.receive
-                                                               if not call_onconnect then  -- trigger listener
-                                                                       self:onstatus("ssl-handshake-complete");
-                                                               end
-                                                               self:_start_session( call_onconnect )
-                                                               debug( "ssl handshake done" )
-                                                               self.eventhandshake = nil
-                                                               return -1
-                                                       end
-                                                       if err == "wantwrite" then
-                                                               event = EV_WRITE
-                                                       elseif err == "wantread" then
-                                                               event = EV_READ
-                                                       else
-                                                               debug( "ssl handshake error:", err )
-                                                               self.fatalerror = err
-                                                       end
-                                               end
-                                               if self.fatalerror then
-                                                       if call_onconnect then
-                                                               self.ondisconnect = nil  -- dont call this when client isnt really connected
-                                                       end
-                                                       self:_close()
-                                                       debug( "handshake failed because:", self.fatalerror )
-                                                       self.eventhandshake = nil
-                                                       return -1
-                                               end
-                                               event = coroutine_yield( event, cfg.HANDSHAKE_TIMEOUT )  -- yield this monster...
-                                       end
-                               end
-                       )
-                       debug "starting handshake..."
-                       self:_lock( false, true, true )  -- unlock read/write events, but keep interface locked
-                       self.eventhandshake = addevent( base, self.conn, EV_READWRITE, handshakecallback, cfg.HANDSHAKE_TIMEOUT )
-                       return true
-       end
-       function interface_mt:_destroy()  -- close this interface + events and call last listener
-                       debug( "closing client with id:", self.id, self.fatalerror )
-                       self:_lock( true, true, true )  -- first of all, lock the interface to avoid further actions
-                       local _
-                       _ = self.eventread and self.eventread:close( )
-                       if self.type == "client" then
-                               _ = self.eventwrite and self.eventwrite:close( )
-                               _ = self.eventhandshake and self.eventhandshake:close( )
-                               _ = self.eventstarthandshake and self.eventstarthandshake:close( )
-                               _ = self.eventconnect and self.eventconnect:close( )
-                               _ = self.eventsession and self.eventsession:close( )
-                               _ = self.eventwritetimeout and self.eventwritetimeout:close( )
-                               _ = self.eventreadtimeout and self.eventreadtimeout:close( )
-                               _ = self.ondisconnect and self:ondisconnect( self.fatalerror ~= "client to close" and self.fatalerror)  -- call ondisconnect listener (wont be the case if handshake failed on connect)
-                               _ = self.conn and self.conn:close( ) -- close connection
-                               _ = self._server and self._server:counter(-1);
-                               self.eventread, self.eventwrite = nil, nil
-                               self.eventstarthandshake, self.eventhandshake, self.eventclose = nil, nil, nil
-                               self.readcallback, self.writecallback = nil, nil
-                       else
-                               self.conn:close( )
-                               self.eventread, self.eventclose = nil, nil
-                               self.interface, self.readcallback = nil, nil
+                               debug( "handshake failed because:", self.fatalerror )
+                               self.eventhandshake = nil
+                               return -1
                        end
-                       interfacelist( "delete", self )
-                       return true
-       end
-       
-       function interface_mt:_lock(nointerface, noreading, nowriting)  -- lock or unlock this interface or events
-                       self.nointerface, self.noreading, self.nowriting = nointerface, noreading, nowriting
-                       return nointerface, noreading, nowriting
-       end
-       
-       --TODO: Deprecate
-       function interface_mt:lock_read(switch)
-               if switch then
-                       return self:pause();
-               else
-                       return self:resume();
+                       event = coroutine_yield( event, cfg.HANDSHAKE_TIMEOUT )  -- yield this monster...
                end
        end
+       )
+       debug "starting handshake..."
+       self:_lock( false, true, true )  -- unlock read/write events, but keep interface locked
+       self.eventhandshake = addevent( base, self.conn, EV_READWRITE, handshakecallback, cfg.HANDSHAKE_TIMEOUT )
+       return true
+end
+function interface_mt:_destroy()  -- close this interface + events and call last listener
+       debug( "closing client with id:", self.id, self.fatalerror )
+       self:_lock( true, true, true )  -- first of all, lock the interface to avoid further actions
+       local _
+       _ = self.eventread and self.eventread:close( )
+       if self.type == "client" then
+               _ = self.eventwrite and self.eventwrite:close( )
+               _ = self.eventhandshake and self.eventhandshake:close( )
+               _ = self.eventstarthandshake and self.eventstarthandshake:close( )
+               _ = self.eventconnect and self.eventconnect:close( )
+               _ = self.eventsession and self.eventsession:close( )
+               _ = self.eventwritetimeout and self.eventwritetimeout:close( )
+               _ = self.eventreadtimeout and self.eventreadtimeout:close( )
+               _ = self.ondisconnect and self:ondisconnect( self.fatalerror ~= "client to close" and self.fatalerror)  -- call ondisconnect listener (wont be the case if handshake failed on connect)
+               _ = self.conn and self.conn:close( ) -- close connection
+               _ = self._server and self._server:counter(-1);
+               self.eventread, self.eventwrite = nil, nil
+               self.eventstarthandshake, self.eventhandshake, self.eventclose = nil, nil, nil
+               self.readcallback, self.writecallback = nil, nil
+       else
+               self.conn:close( )
+               self.eventread, self.eventclose = nil, nil
+               self.interface, self.readcallback = nil, nil
+       end
+       interfacelist[ self ] = nil
+       return true
+end
 
-       function interface_mt:pause()
-               return self:_lock(self.nointerface, true, self.nowriting);
-       end
+function interface_mt:_lock(nointerface, noreading, nowriting)  -- lock or unlock this interface or events
+       self.nointerface, self.noreading, self.nowriting = nointerface, noreading, nowriting
+       return nointerface, noreading, nowriting
+end
 
-       function interface_mt:resume()
-               self:_lock(self.nointerface, false, self.nowriting);
-               if self.readcallback and not self.eventread then
-                       self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
-                       return true;
-               end
+--TODO: Deprecate
+function interface_mt:lock_read(switch)
+       if switch then
+               return self:pause();
+       else
+               return self:resume();
        end
+end
 
-       function interface_mt:counter(c)
-               if c then
-                       self._connections = self._connections + c
-               end
-               return self._connections
-       end
-       
-       -- Public methods
-       function interface_mt:write(data)
-               if self.nowriting then return nil, "locked" end
-               --vdebug( "try to send data to client, id/data:", self.id, data )
-               data = tostring( data )
-               local len = #data
-               local total = len + self.writebufferlen
-               if total > cfg.MAX_SEND_LENGTH then  -- check buffer length
-                       local err = "send buffer exceeded"
-                       debug( "error:", err )  -- to much, check your app
-                       return nil, err
-               end
-               t_insert(self.writebuffer, data) -- new buffer
-               self.writebufferlen = total
-               if not self.eventwrite then  -- register new write event
-                       --vdebug( "register new write event" )
-                       self.eventwrite = addevent( base, self.conn, EV_WRITE, self.writecallback, cfg.WRITE_TIMEOUT )
-               end
-               return true
-       end
-       function interface_mt:close()
-               if self.nointerface then return nil, "locked"; end
-               debug( "try to close client connection with id:", self.id )
-               if self.type == "client" then
-                       self.fatalerror = "client to close"
-                       if self.eventwrite then -- wait for incomplete write request
-                               self:_lock( true, true, false )
-                               debug "closing delayed until writebuffer is empty"
-                               return nil, "writebuffer not empty, waiting"
-                       else -- close now
-                               self:_lock( true, true, true )
-                               self:_close()
-                               return true
-                       end
-               else
-                       debug( "try to close server with id:", tostring(self.id))
-                       self.fatalerror = "server to close"
-                       self:_lock( true )
-                       self:_close( 0 )
-                       return true
-               end
-       end
-       
-       function interface_mt:socket()
-               return self.conn
-       end
-       
-       function interface_mt:server()
-               return self._server or self;
-       end
-       
-       function interface_mt:port()
-               return self._port
-       end
-       
-       function interface_mt:serverport()
-               return self._serverport
-       end
-       
-       function interface_mt:ip()
-               return self._ip
-       end
-       
-       function interface_mt:ssl()
-               return self._usingssl
-       end
-       interface_mt.clientport = interface_mt.port -- COMPAT server_select
+function interface_mt:pause()
+       return self:_lock(self.nointerface, true, self.nowriting);
+end
 
-       function interface_mt:type()
-               return self._type or "client"
-       end
-       
-       function interface_mt:connections()
-               return self._connections
-       end
-       
-       function interface_mt:address()
-               return self.addr
+function interface_mt:resume()
+       self:_lock(self.nointerface, false, self.nowriting);
+       if self.readcallback and not self.eventread then
+               self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
+               return true;
        end
-       
-       function interface_mt:set_sslctx(sslctx)
-               self._sslctx = sslctx;
-               if sslctx then
-                       self.starttls = nil; -- use starttls() of interface_mt
-               else
-                       self.starttls = false; -- prevent starttls()
-               end
+end
+
+function interface_mt:counter(c)
+       if c then
+               self._connections = self._connections + c
        end
+       return self._connections
+end
 
-       function interface_mt:set_mode(pattern)
-               if pattern then
-                       self._pattern = pattern;
-               end
-               return self._pattern;
-       end
-       
-       function interface_mt:set_send(new_send)
-               -- No-op, we always use the underlying connection's send
-       end
-       
-       function interface_mt:starttls(sslctx, call_onconnect)
-               debug( "try to start ssl at client id:", self.id )
-               local err
-               self._sslctx = sslctx;
-               if self._usingssl then  -- startssl was already called
-                       err = "ssl already active"
-               end
-               if err then
-                       debug( "error:", err )
-                       return nil, err
-               end
-               self._usingssl = true
-               self.startsslcallback = function( )  -- we have to start the handshake outside of a read/write event
-                       self.startsslcallback = nil
-                       self:_start_ssl(call_onconnect);
-                       self.eventstarthandshake = nil
-                       return -1
-               end
-               if not self.eventwrite then
-                       self:_lock( true, true, true )  -- lock the interface, to not disturb the handshake
-                       self.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, self.startsslcallback, 0 )  -- add event to start handshake
-               else  -- wait until writebuffer is empty
+-- Public methods
+function interface_mt:write(data)
+       if self.nowriting then return nil, "locked" end
+       --vdebug( "try to send data to client, id/data:", self.id, data )
+       data = tostring( data )
+       local len = #data
+       local total = len + self.writebufferlen
+       if total > cfg.MAX_SEND_LENGTH then  -- check buffer length
+               local err = "send buffer exceeded"
+               debug( "error:", err )  -- to much, check your app
+               return nil, err
+       end
+       t_insert(self.writebuffer, data) -- new buffer
+       self.writebufferlen = total
+       if not self.eventwrite then  -- register new write event
+               --vdebug( "register new write event" )
+               self.eventwrite = addevent( base, self.conn, EV_WRITE, self.writecallback, cfg.WRITE_TIMEOUT )
+       end
+       return true
+end
+function interface_mt:close()
+       if self.nointerface then return nil, "locked"; end
+       debug( "try to close client connection with id:", self.id )
+       if self.type == "client" then
+               self.fatalerror = "client to close"
+               if self.eventwrite then -- wait for incomplete write request
                        self:_lock( true, true, false )
-                       debug "ssl session delayed until writebuffer is empty..."
+                       debug "closing delayed until writebuffer is empty"
+                       return nil, "writebuffer not empty, waiting"
+               else -- close now
+                       self:_lock( true, true, true )
+                       self:_close()
+                       return true
                end
-               self.starttls = false;
+       else
+               debug( "try to close server with id:", tostring(self.id))
+               self.fatalerror = "server to close"
+               self:_lock( true )
+               self:_close( 0 )
                return true
        end
-       
-       function interface_mt:setoption(option, value)
-               if self.conn.setoption then
-                       return self.conn:setoption(option, value);
-               end
-               return false, "setoption not implemented";
-       end
-       
-       function interface_mt:setlistener(listener)
-               self:ondetach(); -- Notify listener that it is no longer responsible for this connection
-               self.onconnect, self.ondisconnect, self.onincoming,
-               self.ontimeout, self.onstatus, self.ondetach
-                       = listener.onconnect, listener.ondisconnect, listener.onincoming,
-                       listener.ontimeout, listener.onstatus, listener.ondetach;
-       end
-       
-       -- Stub handlers
-       function interface_mt:onconnect()
-       end
-       function interface_mt:onincoming()
-       end
-       function interface_mt:ondisconnect()
-       end
-       function interface_mt:ontimeout()
-       end
-       function interface_mt:ondrain()
+end
+
+function interface_mt:socket()
+       return self.conn
+end
+
+function interface_mt:server()
+       return self._server or self;
+end
+
+function interface_mt:port()
+       return self._port
+end
+
+function interface_mt:serverport()
+       return self._serverport
+end
+
+function interface_mt:ip()
+       return self._ip
+end
+
+function interface_mt:ssl()
+       return self._usingssl
+end
+interface_mt.clientport = interface_mt.port -- COMPAT server_select
+
+function interface_mt:type()
+       return self._type or "client"
+end
+
+function interface_mt:connections()
+       return self._connections
+end
+
+function interface_mt:address()
+       return self.addr
+end
+
+function interface_mt:set_sslctx(sslctx)
+       self._sslctx = sslctx;
+       if sslctx then
+               self.starttls = nil; -- use starttls() of interface_mt
+       else
+               self.starttls = false; -- prevent starttls()
        end
-       function interface_mt:ondetach()
+end
+
+function interface_mt:set_mode(pattern)
+       if pattern then
+               self._pattern = pattern;
        end
-       function interface_mt:onstatus()
+       return self._pattern;
+end
+
+function interface_mt:set_send(new_send) -- luacheck: ignore 212
+       -- No-op, we always use the underlying connection's send
+end
+
+function interface_mt:starttls(sslctx, call_onconnect)
+       debug( "try to start ssl at client id:", self.id )
+       local err
+       self._sslctx = sslctx;
+       if self._usingssl then  -- startssl was already called
+               err = "ssl already active"
+       end
+       if err then
+               debug( "error:", err )
+               return nil, err
+       end
+       self._usingssl = true
+       self.startsslcallback = function( )  -- we have to start the handshake outside of a read/write event
+               self.startsslcallback = nil
+               self:_start_ssl(call_onconnect);
+               self.eventstarthandshake = nil
+               return -1
+       end
+       if not self.eventwrite then
+               self:_lock( true, true, true )  -- lock the interface, to not disturb the handshake
+               self.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, self.startsslcallback, 0 )  -- add event to start handshake
+       else
+               -- wait until writebuffer is empty
+               self:_lock( true, true, false )
+               debug "ssl session delayed until writebuffer is empty..."
+       end
+       self.starttls = false;
+       return true
+end
+
+function interface_mt:setoption(option, value)
+       if self.conn.setoption then
+               return self.conn:setoption(option, value);
        end
+       return false, "setoption not implemented";
+end
+
+function interface_mt:setlistener(listener)
+       self:ondetach(); -- Notify listener that it is no longer responsible for this connection
+       self.onconnect = listener.onconnect;
+       self.ondisconnect = listener.ondisconnect;
+       self.onincoming = listener.onincoming;
+       self.ontimeout = listener.ontimeout;
+       self.onreadtimeout = listener.onreadtimeout;
+       self.onstatus = listener.onstatus;
+       self.ondetach = listener.ondetach;
+end
+
+-- Stub handlers
+function interface_mt:onconnect()
+end
+function interface_mt:onincoming()
+end
+function interface_mt:ondisconnect()
+end
+function interface_mt:ontimeout()
+end
+function interface_mt:onreadtimeout()
+       self.fatalerror = "timeout during receiving"
+       debug( "connection failed:", self.fatalerror )
+       self:_close()
+       self.eventread = nil
+end
+function interface_mt:ondrain()
+end
+function interface_mt:ondetach()
+end
+function interface_mt:onstatus()
 end
 
 -- End of client interface methods
 
-local handleclient;
-do
-       local string_sub = string.sub  -- caching table lookups
-       local addevent = base.addevent
-       local socket_gettime = socket.gettime
-       function handleclient( client, ip, port, server, pattern, listener, sslctx )  -- creates an client interface
-               --vdebug("creating client interfacce...")
-               local interface = {
-                       type = "client";
-                       conn = client;
-                       currenttime = socket_gettime( );  -- safe the origin
-                       writebuffer = {};  -- writebuffer
-                       writebufferlen = 0;  -- length of writebuffer
-                       send = client.send;  -- caching table lookups
-                       receive = client.receive;
-                       onconnect = listener.onconnect;  -- will be called when client disconnects
-                       ondisconnect = listener.ondisconnect;  -- will be called when client disconnects
-                       onincoming = listener.onincoming;  -- will be called when client sends data
-                       ontimeout = listener.ontimeout; -- called when fatal socket timeout occurs
-                       ondrain = listener.ondrain; -- called when writebuffer is empty
-                       ondetach = listener.ondetach; -- called when disassociating this listener from this connection
-                       onstatus = listener.onstatus; -- called for status changes (e.g. of SSL/TLS)
-                       eventread = false, eventwrite = false, eventclose = false,
-                       eventhandshake = false, eventstarthandshake = false;  -- event handler
-                       eventconnect = false, eventsession = false;  -- more event handler...
-                       eventwritetimeout = false;  -- even more event handler...
-                       eventreadtimeout = false;
-                       fatalerror = false;  -- error message
-                       writecallback = false;  -- will be called on write events
-                       readcallback = false;  -- will be called on read events
-                       nointerface = true;  -- lock/unlock parameter of this interface
-                       noreading = false, nowriting = false;  -- locks of the read/writecallback
-                       startsslcallback = false;  -- starting handshake callback
-                       position = false;  -- position of client in interfacelist
-                       
-                       -- Properties
-                       _ip = ip, _port = port, _server = server, _pattern = pattern,
-                       _serverport = (server and server:port() or nil),
-                       _sslctx = sslctx; -- parameters
-                       _usingssl = false;  -- client is using ssl;
-               }
-               if not ssl then interface.starttls = false; end
-               interface.id = tostring(interface):match("%x+$");
-               interface.writecallback = function( event )  -- called on write events
-                       --vdebug( "new client write event, id/ip/port:", interface, ip, port )
-                       if interface.nowriting or ( interface.fatalerror and ( "client to close" ~= interface.fatalerror ) ) then  -- leave this event
-                               --vdebug( "leaving this event because:", interface.nowriting or interface.fatalerror )
-                               interface.eventwrite = false
-                               return -1
-                       end
-                       if EV_TIMEOUT == event then  -- took too long to write some data to socket -> disconnect
-                               interface.fatalerror = "timeout during writing"
-                               debug( "writing failed:", interface.fatalerror )
-                               interface:_close()
-                               interface.eventwrite = false
-                               return -1
-                       else  -- can write :)
-                               if interface._usingssl then  -- handle luasec
-                                       if interface.eventreadtimeout then  -- we have to read first
-                                               local ret = interface.readcallback( )  -- call readcallback
-                                               --vdebug( "tried to read in writecallback, result:", ret )
-                                       end
-                                       if interface.eventwritetimeout then  -- luasec only
-                                               interface.eventwritetimeout:close( )  -- first we have to close timeout event which where regged after a wantread error
-                                               interface.eventwritetimeout = false
-                                       end
+local function handleclient( client, ip, port, server, pattern, listener, sslctx )  -- creates an client interface
+       --vdebug("creating client interfacce...")
+       local interface = {
+               type = "client";
+               conn = client;
+               currenttime = socket_gettime( );  -- safe the origin
+               writebuffer = {};  -- writebuffer
+               writebufferlen = 0;  -- length of writebuffer
+               send = client.send;  -- caching table lookups
+               receive = client.receive;
+               onconnect = listener.onconnect;  -- will be called when client disconnects
+               ondisconnect = listener.ondisconnect;  -- will be called when client disconnects
+               onincoming = listener.onincoming;  -- will be called when client sends data
+               ontimeout = listener.ontimeout; -- called when fatal socket timeout occurs
+               onreadtimeout = listener.onreadtimeout; -- called when socket inactivity timeout occurs
+               ondrain = listener.ondrain; -- called when writebuffer is empty
+               ondetach = listener.ondetach; -- called when disassociating this listener from this connection
+               onstatus = listener.onstatus; -- called for status changes (e.g. of SSL/TLS)
+               eventread = false, eventwrite = false, eventclose = false,
+               eventhandshake = false, eventstarthandshake = false;  -- event handler
+               eventconnect = false, eventsession = false;  -- more event handler...
+               eventwritetimeout = false;  -- even more event handler...
+               eventreadtimeout = false;
+               fatalerror = false;  -- error message
+               writecallback = false;  -- will be called on write events
+               readcallback = false;  -- will be called on read events
+               nointerface = true;  -- lock/unlock parameter of this interface
+               noreading = false, nowriting = false;  -- locks of the read/writecallback
+               startsslcallback = false;  -- starting handshake callback
+               position = false;  -- position of client in interfacelist
+
+               -- Properties
+               _ip = ip, _port = port, _server = server, _pattern = pattern,
+               _serverport = (server and server:port() or nil),
+               _sslctx = sslctx; -- parameters
+               _usingssl = false;  -- client is using ssl;
+       }
+       if not has_luasec then interface.starttls = false; end
+       interface.id = tostring(interface):match("%x+$");
+       interface.writecallback = function( event )  -- called on write events
+               --vdebug( "new client write event, id/ip/port:", interface, ip, port )
+               if interface.nowriting or ( interface.fatalerror and ( "client to close" ~= interface.fatalerror ) ) then  -- leave this event
+                       --vdebug( "leaving this event because:", interface.nowriting or interface.fatalerror )
+                       interface.eventwrite = false
+                       return -1
+               end
+               if EV_TIMEOUT == event then  -- took too long to write some data to socket -> disconnect
+                       interface.fatalerror = "timeout during writing"
+                       debug( "writing failed:", interface.fatalerror )
+                       interface:_close()
+                       interface.eventwrite = false
+                       return -1
+               else  -- can write :)
+                       if interface._usingssl then  -- handle luasec
+                               if interface.eventreadtimeout then  -- we have to read first
+                                       local ret = interface.readcallback( )  -- call readcallback
+                                       --vdebug( "tried to read in writecallback, result:", ret )
                                end
-                               interface.writebuffer = { t_concat(interface.writebuffer) }
-                               local succ, err, byte = interface.conn:send( interface.writebuffer[1], 1, interface.writebufferlen )
-                               --vdebug( "write data:", interface.writebuffer, "error:", err, "part:", byte )
-                               if succ then  -- writing succesful
-                                       interface.writebuffer[1] = nil
-                                       interface.writebufferlen = 0
-                                       interface:ondrain();
-                                       if interface.fatalerror then
-                                               debug "closing client after writing"
-                                               interface:_close()  -- close interface if needed
-                                       elseif interface.startsslcallback then  -- start ssl connection if needed
-                                               debug "starting ssl handshake after writing"
-                                               interface.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, interface.startsslcallback, 0 )
-                                       elseif interface.writebufferlen ~= 0 then
-                                               -- data possibly written from ondrain
-                                               return EV_WRITE, cfg.WRITE_TIMEOUT
-                                       elseif interface.eventreadtimeout then
-                                               return EV_WRITE, cfg.WRITE_TIMEOUT
-                                       end
-                                       interface.eventwrite = nil
-                                       return -1
-                               elseif byte and (err == "timeout" or err == "wantwrite") then  -- want write again
-                                       --vdebug( "writebuffer is not empty:", err )
-                                       interface.writebuffer[1] = string_sub( interface.writebuffer[1], byte + 1, interface.writebufferlen )  -- new buffer
-                                       interface.writebufferlen = interface.writebufferlen - byte
-                                       if "wantread" == err then  -- happens only with luasec
-                                               local callback = function( )
-                                                       interface:_close()
-                                                       interface.eventwritetimeout = nil
-                                                       return -1;
-                                               end
-                                               interface.eventwritetimeout = addevent( base, nil, EV_TIMEOUT, callback, cfg.WRITE_TIMEOUT )  -- reg a new timeout event
-                                               debug( "wantread during write attempt, reg it in readcallback but dont know what really happens next..." )
-                                               -- hopefully this works with luasec; its simply not possible to use 2 different write events on a socket in luaevent
-                                               return -1
-                                       end
-                                       return EV_WRITE, cfg.WRITE_TIMEOUT
-                               else  -- connection was closed during writing or fatal error
-                                       interface.fatalerror = err or "fatal error"
-                                       debug( "connection failed in write event:", interface.fatalerror )
-                                       interface:_close()
-                                       interface.eventwrite = nil
-                                       return -1
+                               if interface.eventwritetimeout then  -- luasec only
+                                       interface.eventwritetimeout:close( )  -- first we have to close timeout event which where regged after a wantread error
+                                       interface.eventwritetimeout = false
                                end
                        end
-               end
-               
-               interface.readcallback = function( event )  -- called on read events
-                       --vdebug( "new client read event, id/ip/port:", tostring(interface.id), tostring(ip), tostring(port) )
-                       if interface.noreading or interface.fatalerror then  -- leave this event
-                               --vdebug( "leaving this event because:", tostring(interface.noreading or interface.fatalerror) )
-                               interface.eventread = nil
-                               return -1
-                       end
-                       if EV_TIMEOUT == event then  -- took too long to get some data from client -> disconnect
-                               interface.fatalerror = "timeout during receiving"
-                               debug( "connection failed:", interface.fatalerror )
-                               interface:_close()
-                               interface.eventread = nil
-                               return -1
-                       else -- can read
-                               if interface._usingssl then  -- handle luasec
-                                       if interface.eventwritetimeout then  -- ok, in the past writecallback was regged
-                                               local ret = interface.writecallback( )  -- call it
-                                               --vdebug( "tried to write in readcallback, result:", tostring(ret) )
-                                       end
-                                       if interface.eventreadtimeout then
-                                               interface.eventreadtimeout:close( )
-                                               interface.eventreadtimeout = nil
-                                       end
-                               end
-                               local buffer, err, part = interface.conn:receive( interface._pattern )  -- receive buffer with "pattern"
-                               --vdebug( "read data:", tostring(buffer), "error:", tostring(err), "part:", tostring(part) )
-                               buffer = buffer or part
-                               if buffer and #buffer > cfg.MAX_READ_LENGTH then  -- check buffer length
-                                       interface.fatalerror = "receive buffer exceeded"
-                                       debug( "fatal error:", interface.fatalerror )
-                                       interface:_close()
-                                       interface.eventread = nil
-                                       return -1
+                       interface.writebuffer = { t_concat(interface.writebuffer) }
+                       local succ, err, byte = interface.conn:send( interface.writebuffer[1], 1, interface.writebufferlen )
+                       --vdebug( "write data:", interface.writebuffer, "error:", err, "part:", byte )
+                       if succ then  -- writing succesful
+                               interface.writebuffer[1] = nil
+                               interface.writebufferlen = 0
+                               interface:ondrain();
+                               if interface.fatalerror then
+                                       debug "closing client after writing"
+                                       interface:_close()  -- close interface if needed
+                               elseif interface.startsslcallback then  -- start ssl connection if needed
+                                       debug "starting ssl handshake after writing"
+                                       interface.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, interface.startsslcallback, 0 )
+                               elseif interface.writebufferlen ~= 0 then
+                                       -- data possibly written from ondrain
+                                       return EV_WRITE, cfg.WRITE_TIMEOUT
+                               elseif interface.eventreadtimeout then
+                                       return EV_WRITE, cfg.WRITE_TIMEOUT
                                end
-                               if err and ( err ~= "timeout" and err ~= "wantread" ) then
-                                       if "wantwrite" == err then -- need to read on write event
-                                               if not interface.eventwrite then  -- register new write event if needed
-                                                       interface.eventwrite = addevent( base, interface.conn, EV_WRITE, interface.writecallback, cfg.WRITE_TIMEOUT )
-                                               end
-                                               interface.eventreadtimeout = addevent( base, nil, EV_TIMEOUT,
-                                                       function( )
-                                                               interface:_close()
-                                                       end, cfg.READ_TIMEOUT
-                                               )
-                                               debug( "wantwrite during read attempt, reg it in writecallback but dont know what really happens next..." )
-                                               -- to be honest i dont know what happens next, if it is allowed to first read, the write etc...
-                                       else  -- connection was closed or fatal error
-                                               interface.fatalerror = err
-                                               debug( "connection failed in read event:", interface.fatalerror )
+                               interface.eventwrite = nil
+                               return -1
+                       elseif byte and (err == "timeout" or err == "wantwrite") then  -- want write again
+                               --vdebug( "writebuffer is not empty:", err )
+                               interface.writebuffer[1] = s_sub( interface.writebuffer[1], byte + 1, interface.writebufferlen )  -- new buffer
+                               interface.writebufferlen = interface.writebufferlen - byte
+                               if "wantread" == err then  -- happens only with luasec
+                                       local callback = function( )
                                                interface:_close()
-                                               interface.eventread = nil
-                                               return -1
+                                               interface.eventwritetimeout = nil
+                                               return -1;
                                        end
-                               else
-                                       interface.onincoming( interface, buffer, err )  -- send new data to listener
-                               end
-                               if interface.noreading then
-                                       interface.eventread = nil;
-                                       return -1;
+                                       interface.eventwritetimeout = addevent( base, nil, EV_TIMEOUT, callback, cfg.WRITE_TIMEOUT )  -- reg a new timeout event
+                                       debug( "wantread during write attempt, reg it in readcallback but dont know what really happens next..." )
+                                       -- hopefully this works with luasec; its simply not possible to use 2 different write events on a socket in luaevent
+                                       return -1
                                end
-                               return EV_READ, cfg.READ_TIMEOUT
+                               return EV_WRITE, cfg.WRITE_TIMEOUT
+                       else  -- connection was closed during writing or fatal error
+                               interface.fatalerror = err or "fatal error"
+                               debug( "connection failed in write event:", interface.fatalerror )
+                               interface:_close()
+                               interface.eventwrite = nil
+                               return -1
                        end
                end
+       end
 
-               client:settimeout( 0 )  -- set non blocking
-               setmetatable(interface, interface_mt)
-               interfacelist( "add", interface )  -- add to interfacelist
-               return interface
-       end
-end
-
-local handleserver
-do
-       function handleserver( server, addr, port, pattern, listener, sslctx )  -- creates an server interface
-               debug "creating server interface..."
-               local interface = {
-                       _connections = 0;
-                       
-                       conn = server;
-                       onconnect = listener.onconnect;  -- will be called when new client connected
-                       eventread = false;  -- read event handler
-                       eventclose = false; -- close event handler
-                       readcallback = false; -- read event callback
-                       fatalerror = false; -- error message
-                       nointerface = true;  -- lock/unlock parameter
-                       
-                       _ip = addr, _port = port, _pattern = pattern,
-                       _sslctx = sslctx;
-               }
-               interface.id = tostring(interface):match("%x+$");
-               interface.readcallback = function( event )  -- server handler, called on incoming connections
-                       --vdebug( "server can accept, id/addr/port:", interface, addr, port )
-                       if interface.fatalerror then
-                               --vdebug( "leaving this event because:", self.fatalerror )
-                               interface.eventread = nil
-                               return -1
-                       end
-                       local delay = cfg.ACCEPT_DELAY
-                       if EV_TIMEOUT == event then
-                               if interface._connections >= cfg.MAX_CONNECTIONS then  -- check connection count
-                                       debug( "to many connections, seconds to wait for next accept:", delay )
-                                       return EV_TIMEOUT, delay  -- timeout...
-                               else
-                                       return EV_READ  -- accept again
-                               end
+       interface.readcallback = function( event )  -- called on read events
+               --vdebug( "new client read event, id/ip/port:", tostring(interface.id), tostring(ip), tostring(port) )
+               if interface.noreading or interface.fatalerror then  -- leave this event
+                       --vdebug( "leaving this event because:", tostring(interface.noreading or interface.fatalerror) )
+                       interface.eventread = nil
+                       return -1
+               end
+               if EV_TIMEOUT == event and interface:onreadtimeout() ~= true then
+                       return -1 -- took too long to get some data from client -> disconnect
+               end
+               if interface._usingssl then  -- handle luasec
+                       if interface.eventwritetimeout then  -- ok, in the past writecallback was regged
+                               local ret = interface.writecallback( )  -- call it
+                               --vdebug( "tried to write in readcallback, result:", tostring(ret) )
                        end
-                       --vdebug("max connection check ok, accepting...")
-                       local client, err = server:accept()    -- try to accept; TODO: check err
-                       while client do
-                               if interface._connections >= cfg.MAX_CONNECTIONS then
-                                       client:close( )  -- refuse connection
-                                       debug( "maximal connections reached, refuse client connection; accept delay:", delay )
-                                       return EV_TIMEOUT, delay  -- delay for next accept attempt
-                               end
-                               local client_ip, client_port = client:getpeername( )
-                               interface._connections = interface._connections + 1  -- increase connection count
-                               local clientinterface = handleclient( client, client_ip, client_port, interface, pattern, listener, sslctx )
-                               --vdebug( "client id:", clientinterface, "startssl:", startssl )
-                               if ssl and sslctx then
-                                       clientinterface:starttls(sslctx, true)
-                               else
-                                       clientinterface:_start_session( true )
-                               end
-                               debug( "accepted incoming client connection from:", client_ip or "<unknown IP>", client_port or "<unknown port>", "to", port or "<unknown port>");
-                               
-                               client, err = server:accept()    -- try to accept again
+                       if interface.eventreadtimeout then
+                               interface.eventreadtimeout:close( )
+                               interface.eventreadtimeout = nil
                        end
-                       return EV_READ
                end
-               
-               server:settimeout( 0 )
-               setmetatable(interface, interface_mt)
-               interfacelist( "add", interface )
-               interface:_start_session()
-               return interface
-       end
-end
-
-local addserver = ( function( )
-       return function( addr, port, listener, pattern, sslcfg, startssl )  -- TODO: check arguments
-               --vdebug( "creating new tcp server with following parameters:", addr or "nil", port or "nil", sslcfg or "nil", startssl or "nil")
-               local server, err = socket.bind( addr, port, cfg.ACCEPT_QUEUE )  -- create server socket
-               if not server then
-                       debug( "creating server socket on "..addr.." port "..port.." failed:", err )
-                       return nil, err
+               local buffer, err, part = interface.conn:receive( interface._pattern )  -- receive buffer with "pattern"
+               --vdebug( "read data:", tostring(buffer), "error:", tostring(err), "part:", tostring(part) )
+               buffer = buffer or part
+               if buffer and #buffer > cfg.MAX_READ_LENGTH then  -- check buffer length
+                       interface.fatalerror = "receive buffer exceeded"
+                       debug( "fatal error:", interface.fatalerror )
+                       interface:_close()
+                       interface.eventread = nil
+                       return -1
                end
-               local sslctx
-               if sslcfg then
-                       if not ssl then
-                               debug "fatal error: luasec not found"
-                               return nil, "luasec not found"
-                       end
-                       sslctx, err = sslcfg
-                       if err then
-                               debug( "error while creating new ssl context for server socket:", err )
-                               return nil, err
+               if err and ( err ~= "timeout" and err ~= "wantread" ) then
+                       if "wantwrite" == err then -- need to read on write event
+                               if not interface.eventwrite then  -- register new write event if needed
+                                       interface.eventwrite = addevent( base, interface.conn, EV_WRITE, interface.writecallback, cfg.WRITE_TIMEOUT )
+                               end
+                               interface.eventreadtimeout = addevent( base, nil, EV_TIMEOUT,
+                               function( )
+                                       interface:_close()
+                               end, cfg.READ_TIMEOUT
+                               )
+                               debug( "wantwrite during read attempt, reg it in writecallback but dont know what really happens next..." )
+                               -- to be honest i dont know what happens next, if it is allowed to first read, the write etc...
+                       else  -- connection was closed or fatal error
+                               interface.fatalerror = err
+                               debug( "connection failed in read event:", interface.fatalerror )
+                               interface:_close()
+                               interface.eventread = nil
+                               return -1
                        end
+               else
+                       interface.onincoming( interface, buffer, err )  -- send new data to listener
+               end
+               if interface.noreading then
+                       interface.eventread = nil;
+                       return -1;
                end
-               local interface = handleserver( server, addr, port, pattern, listener, sslctx, startssl )  -- new server handler
-               debug( "new server created with id:", tostring(interface))
-               return interface
+               return EV_READ, cfg.READ_TIMEOUT
        end
-end )( )
 
-local addclient, wrapclient
-do
-       function wrapclient( client, ip, port, listeners, pattern, sslctx )
-               local interface = handleclient( client, ip, port, nil, pattern, listeners, sslctx )
-               interface:_start_connection(sslctx)
-               return interface, client
-               --function handleclient( client, ip, port, server, pattern, listener, _, sslctx )  -- creates an client interface
-       end
-       
-       function addclient( addr, serverport, listener, pattern, localaddr, localport, sslcfg, startssl )
-               local client, err = socket.tcp()  -- creating new socket
-               if not client then
-                       debug( "cannot create socket:", err )
-                       return nil, err
+       client:settimeout( 0 )  -- set non blocking
+       setmetatable(interface, interface_mt)
+       interfacelist[ interface ] = true  -- add to interfacelist
+       return interface
+end
+
+local function handleserver( server, addr, port, pattern, listener, sslctx )  -- creates an server interface
+       debug "creating server interface..."
+       local interface = {
+               _connections = 0;
+
+               type = "server";
+               conn = server;
+               onconnect = listener.onconnect;  -- will be called when new client connected
+               eventread = false;  -- read event handler
+               eventclose = false; -- close event handler
+               readcallback = false; -- read event callback
+               fatalerror = false; -- error message
+               nointerface = true;  -- lock/unlock parameter
+
+               _ip = addr, _port = port, _pattern = pattern,
+               _sslctx = sslctx;
+       }
+       interface.id = tostring(interface):match("%x+$");
+       interface.readcallback = function( event )  -- server handler, called on incoming connections
+               --vdebug( "server can accept, id/addr/port:", interface, addr, port )
+               if interface.fatalerror then
+                       --vdebug( "leaving this event because:", self.fatalerror )
+                       interface.eventread = nil
+                       return -1
                end
-               client:settimeout( 0 )  -- set nonblocking
-               if localaddr then
-                       local res, err = client:bind( localaddr, localport, -1 )
-                       if not res then
-                               debug( "cannot bind client:", err )
-                               return nil, err
+               local delay = cfg.ACCEPT_DELAY
+               if EV_TIMEOUT == event then
+                       if interface._connections >= cfg.MAX_CONNECTIONS then  -- check connection count
+                               debug( "to many connections, seconds to wait for next accept:", delay )
+                               return EV_TIMEOUT, delay  -- timeout...
+                       else
+                               return EV_READ  -- accept again
                        end
                end
-               local sslctx
-               if sslcfg then  -- handle ssl/new context
-                       if not ssl then
-                               debug "need luasec, but not available"
-                               return nil, "luasec not found"
+               --vdebug("max connection check ok, accepting...")
+               local client, err = server:accept()    -- try to accept; TODO: check err
+               while client do
+                       if interface._connections >= cfg.MAX_CONNECTIONS then
+                               client:close( )  -- refuse connection
+                               debug( "maximal connections reached, refuse client connection; accept delay:", delay )
+                               return EV_TIMEOUT, delay  -- delay for next accept attempt
                        end
-                       sslctx, err = sslcfg
-                       if err then
-                               debug( "cannot create new ssl context:", err )
-                               return nil, err
+                       local client_ip, client_port = client:getpeername( )
+                       interface._connections = interface._connections + 1  -- increase connection count
+                       local clientinterface = handleclient( client, client_ip, client_port, interface, pattern, listener, sslctx )
+                       --vdebug( "client id:", clientinterface, "startssl:", startssl )
+                       if has_luasec and sslctx then
+                               clientinterface:starttls(sslctx, true)
+                       else
+                               clientinterface:_start_session( true )
                        end
+                       debug( "accepted incoming client connection from:", client_ip or "<unknown IP>", client_port or "<unknown port>", "to", port or "<unknown port>");
+
+                       client, err = server:accept()    -- try to accept again
                end
-               local res, err = client:connect( addr, serverport )  -- connect
-               if res or ( err == "timeout" ) then
-                       local ip, port = client:getsockname( )
-                       local interface = wrapclient( client, ip, serverport, listener, pattern, sslctx, startssl )
-                       interface:_start_connection( startssl )
-                       debug( "new connection id:", interface.id )
-                       return interface, err
+               return EV_READ
+       end
+
+       server:settimeout( 0 )
+       setmetatable(interface, interface_mt)
+       interfacelist[ interface ] = true
+       interface:_start_session()
+       return interface
+end
+
+local function addserver( addr, port, listener, pattern, sslctx, startssl )  -- TODO: check arguments
+       --vdebug( "creating new tcp server with following parameters:", addr or "nil", port or "nil", sslctx or "nil", startssl or "nil")
+       if sslctx and not has_luasec then
+               debug "fatal error: luasec not found"
+               return nil, "luasec not found"
+       end
+       local server, err = socket.bind( addr, port, cfg.ACCEPT_QUEUE )  -- create server socket
+       if not server then
+               debug( "creating server socket on "..addr.." port "..port.." failed:", err )
+               return nil, err
+       end
+       local interface = handleserver( server, addr, port, pattern, listener, sslctx, startssl )  -- new server handler
+       debug( "new server created with id:", tostring(interface))
+       return interface
+end
+
+local function wrapclient( client, ip, port, listeners, pattern, sslctx )
+       local interface = handleclient( client, ip, port, nil, pattern, listeners, sslctx )
+       interface:_start_connection(sslctx)
+       return interface, client
+       --function handleclient( client, ip, port, server, pattern, listener, _, sslctx )  -- creates an client interface
+end
+
+local function addclient( addr, serverport, listener, pattern, sslctx, typ )
+       if sslctx and not has_luasec then
+               debug "need luasec, but not available"
+               return nil, "luasec not found"
+       end
+       if not typ then
+               local addrinfo, err = getaddrinfo(addr)
+               if not addrinfo then return nil, err end
+               if addrinfo[1] and addrinfo[1].family == "inet6" then
+                       typ = "tcp6"
                else
-                       debug( "new connection failed:", err )
-                       return nil, err
+                       typ = "tcp"
                end
        end
+       local create = socket[typ]
+       if type( create ) ~= "function"  then
+               return nil, "invalid socket type"
+       end
+       local client, err = create()  -- creating new socket
+       if not client then
+               debug( "cannot create socket:", err )
+               return nil, err
+       end
+       client:settimeout( 0 )  -- set nonblocking
+       local res, err = client:connect( addr, serverport )  -- connect
+       if res or ( err == "timeout" ) then
+               local ip, port = client:getsockname( )
+               local interface = wrapclient( client, ip, serverport, listener, pattern, sslctx )
+               debug( "new connection id:", interface.id )
+               return interface, err
+       else
+               debug( "new connection failed:", err )
+               return nil, err
+       end
 end
 
-
-local loop = function( )  -- starts the event loop
+local function loop( )  -- starts the event loop
        base:loop( )
        return "quitting";
 end
 
-local newevent = ( function( )
-       local add = base.addevent
-       return function( ... )
-               return add( base, ... )
-       end
-end )( )
+local function newevent( ... )
+       return addevent( base, ... )
+end
 
-local closeallservers = function( arg )
-       for _, item in ipairs( interfacelist( ) ) do
+local function closeallservers ( arg )
+       for item in pairs( interfacelist ) do
                if item.type == "server" then
                        item:close( arg )
                end
@@ -815,9 +760,9 @@ end
 
 local function setquitting(yes)
        if yes then
-                -- Quit now
-                closeallservers();
-                base:loopexit();
+               -- Quit now
+               closeallservers();
+               base:loopexit();
        end
 end
 
@@ -829,7 +774,7 @@ end
 -- being garbage-collected
 local signal_events = {}; -- [signal_num] -> event object
 local function hook_signal(signal_num, handler)
-       local function _handler(event)
+       local function _handler()
                local ret = handler();
                if ret ~= false then -- Continue handling this signal?
                        return EV_SIGNAL; -- Yes
@@ -842,14 +787,14 @@ end
 
 local function link(sender, receiver, buffersize)
        local sender_locked;
-       
+
        function receiver:ondrain()
                if sender_locked then
                        sender:resume();
                        sender_locked = nil;
                end
        end
-       
+
        function sender:onincoming(data)
                receiver:write(data);
                if receiver.writebufferlen >= buffersize then
@@ -861,12 +806,11 @@ local function link(sender, receiver, buffersize)
 end
 
 return {
-
        cfg = cfg,
        base = base,
        loop = loop,
        link = link,
-       event = event,
+       event = levent,
        event_base = base,
        addevent = newevent,
        addserver = addserver,