2 -- server.lua by blastbeat of the luadch project
3 -- Re-used here under the MIT/X Consortium License
5 -- Modifications (C) 2008-2010 Matthew Wild, Waqas Hussain
8 -- // wrapping luadch stuff // --
10 local use = function( what )
14 local log, table_concat = require ("util.logger").init("socket"), table.concat;
15 local out_put = function (...) return log("debug", table_concat{...}); end
16 local out_error = function (...) return log("warn", table_concat{...}); end
18 ----------------------------------// DECLARATION //--
22 local STAT_UNIT = 1 -- byte
24 --// lua functions //--
26 local type = use "type"
27 local pairs = use "pairs"
28 local ipairs = use "ipairs"
29 local tonumber = use "tonumber"
30 local tostring = use "tostring"
35 local table = use "table"
36 local string = use "string"
37 local coroutine = use "coroutine"
39 --// lua lib methods //--
41 local os_difftime = os.difftime
42 local math_min = math.min
43 local math_huge = math.huge
44 local table_concat = table.concat
45 local string_sub = string.sub
46 local coroutine_wrap = coroutine.wrap
47 local coroutine_yield = coroutine.yield
51 local luasec = use "ssl"
52 local luasocket = use "socket" or require "socket"
53 local luasocket_gettime = luasocket.gettime
55 --// extern lib methods //--
57 local ssl_wrap = ( luasec and luasec.wrap )
58 local socket_bind = luasocket.bind
59 local socket_sleep = luasocket.sleep
60 local socket_select = luasocket.select
92 --// simple data types //--
121 local _maxsslhandshake
123 ----------------------------------// DEFINITION //--
125 _server = { } -- key = port, value = table; list of listening servers
126 _readlist = { } -- array with sockets to read from
127 _sendlist = { } -- arrary with sockets to write to
128 _timerlist = { } -- array of timer functions
129 _socketlist = { } -- key = socket, value = wrapped socket (handlers)
130 _readtimes = { } -- key = handler, value = timestamp of last data reading
131 _writetimes = { } -- key = handler, value = timestamp of last data writing/sending
132 _closelist = { } -- handlers to close
134 _readlistlen = 0 -- length of readlist
135 _sendlistlen = 0 -- length of sendlist
136 _timerlistlen = 0 -- lenght of timerlist
138 _sendtraffic = 0 -- some stats
141 _selecttimeout = 1 -- timeout of socket.select
142 _sleeptime = 0 -- time to wait at the end of every loop
143 _tcpbacklog = 128 -- some kind of hint to the OS
145 _maxsendlen = 51000 * 1024 -- max len of send buffer
146 _maxreadlen = 25000 * 1024 -- max len of read buffer
148 _checkinterval = 30 -- interval in secs to check idle clients
149 _sendtimeout = 60000 -- allowed send idle time in secs
150 _readtimeout = 6 * 60 * 60 -- allowed read idle time in secs
152 local is_windows = package.config:sub(1,1) == "\\" -- check the directory separator, to detemine whether this is Windows
153 _maxfd = (is_windows and math.huge) or luasocket._SETSIZE or 1024 -- max fd number, limit to 1024 by default to prevent glibc buffer overflow, but not on Windows
154 _maxselectlen = luasocket._SETSIZE or 1024 -- But this still applies on Windows
156 _maxsslhandshake = 30 -- max handshake round-trips
158 ----------------------------------// PRIVATE //--
160 wrapserver = function( listeners, socket, ip, serverport, pattern, sslctx ) -- this function wraps a server -- FIXME Make sure FD < _maxfd
162 if socket:getfd() >= _maxfd then
163 out_error("server.lua: Disallowed FD number: "..socket:getfd())
165 return nil, "fd-too-large"
168 local connections = 0
170 local dispatch, disconnect = listeners.onconnect, listeners.ondisconnect
172 local accept = socket.accept
174 --// public methods of the object //--
178 handler.shutdown = function( ) end
180 handler.ssl = function( )
183 handler.sslctx = function( )
186 handler.remove = function( )
187 connections = connections - 1
192 handler.close = function()
194 _sendlistlen = removesocket( _sendlist, socket, _sendlistlen )
195 _readlistlen = removesocket( _readlist, socket, _readlistlen )
196 _server[ip..":"..serverport] = nil;
197 _socketlist[ socket ] = nil
201 out_put "server.lua: closed server handler and removed sockets from list"
203 handler.pause = function( hard )
204 if not handler.paused then
205 _readlistlen = removesocket( _readlist, socket, _readlistlen )
207 _socketlist[ socket ] = nil
211 handler.paused = true;
214 handler.resume = function( )
215 if handler.paused then
217 socket = socket_bind( ip, serverport, _tcpbacklog );
218 socket:settimeout( 0 )
220 _readlistlen = addsocket(_readlist, socket, _readlistlen)
221 _socketlist[ socket ] = handler
222 handler.paused = false;
225 handler.ip = function( )
228 handler.serverport = function( )
231 handler.socket = function( )
234 handler.readbuffer = function( )
235 if _readlistlen >= _maxselectlen or _sendlistlen >= _maxselectlen then
237 out_put( "server.lua: refused new client connection: server full" )
240 local client, err = accept( socket ) -- try to accept
242 local ip, clientport = client:getpeername( )
243 local handler, client, err = wrapconnection( handler, listeners, client, ip, serverport, clientport, pattern, sslctx ) -- wrap new client socket
244 if err then -- error while wrapping ssl socket
247 connections = connections + 1
248 out_put( "server.lua: accepted new client connection from ", tostring(ip), ":", tostring(clientport), " to ", tostring(serverport))
249 if dispatch and not sslctx then -- SSL connections will notify onconnect when handshake completes
250 return dispatch( handler );
253 elseif err then -- maybe timeout or something else
254 out_put( "server.lua: error with new client connection: ", tostring(err) )
261 wrapconnection = function( server, listeners, socket, ip, serverport, clientport, pattern, sslctx ) -- this function wraps a client to a handler object
263 if socket:getfd() >= _maxfd then
264 out_error("server.lua: Disallowed FD number: "..socket:getfd()) -- PROTIP: Switch to libevent
265 socket:close( ) -- Should we send some kind of error here?
269 return nil, nil, "fd-too-large"
271 socket:settimeout( 0 )
273 --// local import of socket methods //--
279 --// private closures of the object //--
283 local dispatch = listeners.onincoming
284 local status = listeners.onstatus
285 local disconnect = listeners.ondisconnect
286 local drain = listeners.ondrain
287 local onreadtimeout = listeners.onreadtimeout;
289 local bufferqueue = { } -- buffer array
290 local bufferqueuelen = 0 -- end of buffer array
301 local sendtraffic, readtraffic = 0, 0
303 local maxsendlen = _maxsendlen
304 local maxreadlen = _maxreadlen
306 --// public methods of the object //--
308 local handler = bufferqueue -- saves a table ^_^
310 handler.dispatch = function( )
313 handler.disconnect = function( )
316 handler.onreadtimeout = onreadtimeout;
318 handler.setlistener = function( self, listeners )
319 dispatch = listeners.onincoming
320 disconnect = listeners.ondisconnect
321 status = listeners.onstatus
322 drain = listeners.ondrain
323 handler.onreadtimeout = listeners.onreadtimeout
325 handler.getstats = function( )
326 return readtraffic, sendtraffic
328 handler.ssl = function( )
331 handler.sslctx = function ( )
334 handler.send = function( _, data, i, j )
335 return send( socket, data, i, j )
337 handler.receive = function( pattern, prefix )
338 return receive( socket, pattern, prefix )
340 handler.shutdown = function( pattern )
341 return shutdown( socket, pattern )
343 handler.setoption = function (self, option, value)
344 if socket.setoption then
345 return socket:setoption(option, value);
347 return false, "setoption not implemented";
349 handler.force_close = function ( self, err )
350 if bufferqueuelen ~= 0 then
351 out_put("server.lua: discarding unwritten data for ", tostring(ip), ":", tostring(clientport))
354 return self:close(err);
356 handler.close = function( self, err )
357 if not handler then return true; end
358 _readlistlen = removesocket( _readlist, socket, _readlistlen )
359 _readtimes[ handler ] = nil
360 if bufferqueuelen ~= 0 then
361 handler.sendbuffer() -- Try now to send any outstanding data
362 if bufferqueuelen ~= 0 then -- Still not empty, so we'll try again later
364 handler.write = nil -- ... but no further writing allowed
371 _ = shutdown and shutdown( socket )
373 _sendlistlen = removesocket( _sendlist, socket, _sendlistlen )
374 _socketlist[ socket ] = nil
377 out_put "server.lua: socket already closed"
380 _writetimes[ handler ] = nil
381 _closelist[ handler ] = nil
382 local _handler = handler;
385 disconnect(_handler, err or false);
392 out_put "server.lua: closed client handler and removed socket from list"
395 handler.ip = function( )
398 handler.serverport = function( )
401 handler.clientport = function( )
404 handler.port = handler.clientport -- COMPAT server_event
405 local write = function( self, data )
406 bufferlen = bufferlen + #data
407 if bufferlen > maxsendlen then
408 _closelist[ handler ] = "send buffer exceeded" -- cannot close the client at the moment, have to wait to the end of the cycle
409 handler.write = idfalse -- dont write anymore
411 elseif socket and not _sendlist[ socket ] then
412 _sendlistlen = addsocket(_sendlist, socket, _sendlistlen)
414 bufferqueuelen = bufferqueuelen + 1
415 bufferqueue[ bufferqueuelen ] = data
417 _writetimes[ handler ] = _writetimes[ handler ] or _currenttime
421 handler.write = write
422 handler.bufferqueue = function( self )
425 handler.socket = function( self )
428 handler.set_mode = function( self, new )
429 pattern = new or pattern
432 handler.set_send = function ( self, newsend )
433 send = newsend or send
436 handler.bufferlen = function( self, readlen, sendlen )
437 maxsendlen = sendlen or maxsendlen
438 maxreadlen = readlen or maxreadlen
439 return bufferlen, maxreadlen, maxsendlen
442 handler.lock_read = function (self, switch)
443 if switch == true then
444 local tmp = _readlistlen
445 _readlistlen = removesocket( _readlist, socket, _readlistlen )
446 _readtimes[ handler ] = nil
447 if _readlistlen ~= tmp then
450 elseif switch == false then
453 _readlistlen = addsocket(_readlist, socket, _readlistlen)
454 _readtimes[ handler ] = _currenttime
459 handler.pause = function (self)
460 return self:lock_read(true);
462 handler.resume = function (self)
463 return self:lock_read(false);
465 handler.lock = function( self, switch )
466 handler.lock_read (switch)
467 if switch == true then
468 handler.write = idfalse
469 local tmp = _sendlistlen
470 _sendlistlen = removesocket( _sendlist, socket, _sendlistlen )
471 _writetimes[ handler ] = nil
472 if _sendlistlen ~= tmp then
475 elseif switch == false then
476 handler.write = write
482 return noread, nosend
484 local _readbuffer = function( ) -- this function reads data
485 local buffer, err, part = receive( socket, pattern ) -- receive buffer with "pattern"
486 if not err or (err == "wantread" or err == "timeout") then -- received something
487 local buffer = buffer or part or ""
489 if len > maxreadlen then
490 handler:close( "receive buffer exceeded" )
493 local count = len * STAT_UNIT
494 readtraffic = readtraffic + count
495 _readtraffic = _readtraffic + count
496 _readtimes[ handler ] = _currenttime
497 --out_put( "server.lua: read data '", buffer:gsub("[^%w%p ]", "."), "', error: ", err )
498 return dispatch( handler, buffer, err )
499 else -- connections was closed or fatal error
500 out_put( "server.lua: client ", tostring(ip), ":", tostring(clientport), " read error: ", tostring(err) )
502 _ = handler and handler:force_close( err )
506 local _sendbuffer = function( ) -- this function sends data
507 local succ, err, byte, buffer, count;
509 buffer = table_concat( bufferqueue, "", 1, bufferqueuelen )
510 succ, err, byte = send( socket, buffer, 1, bufferlen )
511 count = ( succ or byte or 0 ) * STAT_UNIT
512 sendtraffic = sendtraffic + count
513 _sendtraffic = _sendtraffic + count
514 for i = bufferqueuelen,1,-1 do
515 bufferqueue[ i ] = nil
517 --out_put( "server.lua: sended '", buffer, "', bytes: ", tostring(succ), ", error: ", tostring(err), ", part: ", tostring(byte), ", to: ", tostring(ip), ":", tostring(clientport) )
519 succ, err, count = false, "unexpected close", 0;
521 if succ then -- sending succesful
524 _sendlistlen = removesocket( _sendlist, socket, _sendlistlen ) -- delete socket from writelist
525 _writetimes[ handler ] = nil
529 _ = needtls and handler:starttls(nil)
530 _ = toclose and handler:force_close( )
532 elseif byte and ( err == "timeout" or err == "wantwrite" ) then -- want write
533 buffer = string_sub( buffer, byte + 1, bufferlen ) -- new buffer
534 bufferqueue[ 1 ] = buffer -- insert new buffer in queue
536 bufferlen = bufferlen - byte
537 _writetimes[ handler ] = _currenttime
539 else -- connection was closed during sending or fatal error
540 out_put( "server.lua: client ", tostring(ip), ":", tostring(clientport), " write error: ", tostring(err) )
542 _ = handler and handler:force_close( err )
549 function handler.set_sslctx(self, new_sslctx)
552 handshake = coroutine_wrap( function( client ) -- create handshake coroutine
554 for i = 1, _maxsslhandshake do
555 _sendlistlen = ( wrote and removesocket( _sendlist, client, _sendlistlen ) ) or _sendlistlen
556 _readlistlen = ( read and removesocket( _readlist, client, _readlistlen ) ) or _readlistlen
557 read, wrote = nil, nil
558 _, err = client:dohandshake( )
560 out_put( "server.lua: ssl handshake done" )
561 handler.readbuffer = _readbuffer -- when handshake is done, replace the handshake function with regular functions
562 handler.sendbuffer = _sendbuffer
563 _ = status and status( handler, "ssl-handshake-complete" )
564 if self.autostart_ssl and listeners.onconnect then
565 listeners.onconnect(self);
567 _readlistlen = addsocket(_readlist, client, _readlistlen)
570 if err == "wantwrite" then
571 _sendlistlen = addsocket(_sendlist, client, _sendlistlen)
573 elseif err == "wantread" then
574 _readlistlen = addsocket(_readlist, client, _readlistlen)
580 coroutine_yield( ) -- handshake not finished
583 out_put( "server.lua: ssl handshake error: ", tostring(err or "handshake too long") )
584 _ = handler and handler:force_close("ssl handshake failed")
585 return false, err -- handshake failed
590 handler.starttls = function( self, _sslctx)
592 handler:set_sslctx(_sslctx);
594 if bufferqueuelen > 0 then
595 out_put "server.lua: we need to do tls, but delaying until send buffer empty"
599 out_put( "server.lua: attempting to start tls on " .. tostring( socket ) )
600 local oldsocket, err = socket
601 socket, err = ssl_wrap( socket, sslctx ) -- wrap socket
603 out_put( "server.lua: error while starting tls on client: ", tostring(err or "unknown error") )
604 return nil, err -- fatal error
607 socket:settimeout( 0 )
609 -- add the new socket to our system
611 receive = socket.receive
613 _socketlist[ socket ] = handler
614 _readlistlen = addsocket(_readlist, socket, _readlistlen)
616 -- remove traces of the old socket
617 _readlistlen = removesocket( _readlist, oldsocket, _readlistlen )
618 _sendlistlen = removesocket( _sendlist, oldsocket, _sendlistlen )
619 _socketlist[ oldsocket ] = nil
621 handler.starttls = nil
624 -- Secure now (if handshake fails connection will close)
627 handler.readbuffer = handshake
628 handler.sendbuffer = handshake
629 return handshake( socket ) -- do handshake
633 handler.readbuffer = _readbuffer
634 handler.sendbuffer = _sendbuffer
636 receive = socket.receive
637 shutdown = ( ssl and id ) or socket.shutdown
639 _socketlist[ socket ] = handler
640 _readlistlen = addsocket(_readlist, socket, _readlistlen)
642 if sslctx and luasec then
643 out_put "server.lua: auto-starting ssl negotiation..."
644 handler.autostart_ssl = true;
645 local ok, err = handler:starttls(sslctx);
651 return handler, socket
657 idfalse = function( )
661 addsocket = function( list, socket, len )
662 if not list[ socket ] then
670 removesocket = function( list, socket, len ) -- this function removes sockets from a list ( copied from copas )
671 local pos = list[ socket ]
674 local last = list[ len ]
676 if last ~= socket then
685 closesocket = function( socket )
686 _sendlistlen = removesocket( _sendlist, socket, _sendlistlen )
687 _readlistlen = removesocket( _readlist, socket, _readlistlen )
688 _socketlist[ socket ] = nil
693 local function link(sender, receiver, buffersize)
695 local _sendbuffer = receiver.sendbuffer;
696 function receiver.sendbuffer()
698 if sender_locked and receiver.bufferlen() < buffersize then
699 sender:lock_read(false); -- Unlock now
704 local _readbuffer = sender.readbuffer;
705 function sender.readbuffer()
707 if not sender_locked and receiver.bufferlen() >= buffersize then
708 sender_locked = true;
709 sender:lock_read(true);
714 ----------------------------------// PUBLIC //--
716 addserver = function( addr, port, listeners, pattern, sslctx ) -- this function provides a way for other scripts to reg a server
718 if type( listeners ) ~= "table" then
719 err = "invalid listener table"
721 if type( port ) ~= "number" or not ( port >= 0 and port <= 65535 ) then
723 elseif _server[ addr..":"..port ] then
724 err = "listeners on '[" .. addr .. "]:" .. port .. "' already exist"
725 elseif sslctx and not luasec then
726 err = "luasec not found"
729 out_error( "server.lua, [", addr, "]:", port, ": ", err )
733 local server, err = socket_bind( addr, port, _tcpbacklog )
735 out_error( "server.lua, [", addr, "]:", port, ": ", err )
738 local handler, err = wrapserver( listeners, server, addr, port, pattern, sslctx ) -- wrap new server socket
743 server:settimeout( 0 )
744 _readlistlen = addsocket(_readlist, server, _readlistlen)
745 _server[ addr..":"..port ] = handler
746 _socketlist[ server ] = handler
747 out_put( "server.lua: new "..(sslctx and "ssl " or "").."server listener on '[", addr, "]:", port, "'" )
751 getserver = function ( addr, port )
752 return _server[ addr..":"..port ];
755 removeserver = function( addr, port )
756 local handler = _server[ addr..":"..port ]
758 return nil, "no server found on '[" .. addr .. "]:" .. tostring( port ) .. "'"
761 _server[ addr..":"..port ] = nil
765 closeall = function( )
766 for _, handler in pairs( _socketlist ) do
768 _socketlist[ _ ] = nil
781 getsettings = function( )
783 select_timeout = _selecttimeout;
784 select_sleep_time = _sleeptime;
785 tcp_backlog = _tcpbacklog;
786 max_send_buffer_size = _maxsendlen;
787 max_receive_buffer_size = _maxreadlen;
788 select_idle_check_interval = _checkinterval;
789 send_timeout = _sendtimeout;
790 read_timeout = _readtimeout;
791 max_connections = _maxselectlen;
792 max_ssl_handshake_roundtrips = _maxsslhandshake;
793 highest_allowed_fd = _maxfd;
797 changesettings = function( new )
798 if type( new ) ~= "table" then
799 return nil, "invalid settings table"
801 _selecttimeout = tonumber( new.select_timeout ) or _selecttimeout
802 _sleeptime = tonumber( new.select_sleep_time ) or _sleeptime
803 _maxsendlen = tonumber( new.max_send_buffer_size ) or _maxsendlen
804 _maxreadlen = tonumber( new.max_receive_buffer_size ) or _maxreadlen
805 _checkinterval = tonumber( new.select_idle_check_interval ) or _checkinterval
806 _tcpbacklog = tonumber( new.tcp_backlog ) or _tcpbacklog
807 _sendtimeout = tonumber( new.send_timeout ) or _sendtimeout
808 _readtimeout = tonumber( new.read_timeout ) or _readtimeout
809 _maxselectlen = new.max_connections or _maxselectlen
810 _maxsslhandshake = new.max_ssl_handshake_roundtrips or _maxsslhandshake
811 _maxfd = new.highest_allowed_fd or _maxfd
815 addtimer = function( listener )
816 if type( listener ) ~= "function" then
817 return nil, "invalid listener function"
819 _timerlistlen = _timerlistlen + 1
820 _timerlist[ _timerlistlen ] = listener
825 return _readtraffic, _sendtraffic, _readlistlen, _sendlistlen, _timerlistlen
830 local function setquitting(quit)
831 quitting = not not quit;
834 loop = function(once) -- this is the main loop of the program
835 if quitting then return "quitting"; end
836 if once then quitting = "once"; end
837 local next_timer_time = math_huge;
839 local read, write, err = socket_select( _readlist, _sendlist, math_min(_selecttimeout, next_timer_time) )
840 for i, socket in ipairs( write ) do -- send data waiting in writequeues
841 local handler = _socketlist[ socket ]
843 handler.sendbuffer( )
845 closesocket( socket )
846 out_put "server.lua: found no handler and closed socket (writelist)" -- this should not happen
849 for i, socket in ipairs( read ) do -- receive data
850 local handler = _socketlist[ socket ]
852 handler.readbuffer( )
854 closesocket( socket )
855 out_put "server.lua: found no handler and closed socket (readlist)" -- this can happen
858 for handler, err in pairs( _closelist ) do
859 handler.disconnect( )( handler, err )
860 handler:force_close() -- forced disconnect
861 _closelist[ handler ] = nil;
863 _currenttime = luasocket_gettime( )
865 -- Check for socket timeouts
866 local difftime = os_difftime( _currenttime - _starttime )
867 if difftime > _checkinterval then
868 _starttime = _currenttime
869 for handler, timestamp in pairs( _writetimes ) do
870 if os_difftime( _currenttime - timestamp ) > _sendtimeout then
871 handler.disconnect( )( handler, "send timeout" )
872 handler:force_close() -- forced disconnect
875 for handler, timestamp in pairs( _readtimes ) do
876 if os_difftime( _currenttime - timestamp ) > _readtimeout then
877 if not(handler.onreadtimeout) or handler:onreadtimeout() ~= true then
878 handler.disconnect( )( handler, "read timeout" )
879 handler:close( ) -- forced disconnect?
886 if _currenttime - _timer >= math_min(next_timer_time, 1) then
887 next_timer_time = math_huge;
888 for i = 1, _timerlistlen do
889 local t = _timerlist[ i ]( _currenttime ) -- fire timers
890 if t then next_timer_time = math_min(next_timer_time, t); end
892 _timer = _currenttime
894 next_timer_time = next_timer_time - (_currenttime - _timer);
897 -- wait some time (0 by default)
898 socket_sleep( _sleeptime )
900 if once and quitting == "once" then quitting = nil; return; end
904 local function step()
908 local function get_backend()
912 --// EXPERIMENTAL //--
914 local wrapclient = function( socket, ip, serverport, listeners, pattern, sslctx )
915 local handler, socket, err = wrapconnection( nil, listeners, socket, ip, serverport, "clientport", pattern, sslctx )
916 if not handler then return nil, err end
917 _socketlist[ socket ] = handler
919 _sendlistlen = addsocket(_sendlist, socket, _sendlistlen)
920 if listeners.onconnect then
921 -- When socket is writeable, call onconnect
922 local _sendbuffer = handler.sendbuffer;
923 handler.sendbuffer = function ()
924 handler.sendbuffer = _sendbuffer;
925 listeners.onconnect(handler);
926 return _sendbuffer(); -- Send any queued outgoing data
930 return handler, socket
933 local addclient = function( address, port, listeners, pattern, sslctx )
934 local client, err = luasocket.tcp( )
938 client:settimeout( 0 )
939 _, err = client:connect( address, port )
940 if err then -- try again
941 return wrapclient( client, address, port, listeners, pattern, sslctx )
943 return wrapconnection( nil, listeners, client, address, port, "clientport", pattern, sslctx )
947 --// EXPERIMENTAL //--
949 ----------------------------------// BEGIN //--
951 use "setmetatable" ( _socketlist, { __mode = "k" } )
952 use "setmetatable" ( _readtimes, { __mode = "k" } )
953 use "setmetatable" ( _writetimes, { __mode = "k" } )
955 _timer = luasocket_gettime( )
956 _starttime = luasocket_gettime( )
958 local function setlogger(new_logger)
959 local old_logger = log;
966 ----------------------------------// PUBLIC INTERFACE //--
969 _addtimer = addtimer,
971 addclient = addclient,
972 wrapclient = wrapclient,
979 addserver = addserver,
980 getserver = getserver,
981 setlogger = setlogger,
982 getsettings = getsettings,
983 setquitting = setquitting,
984 removeserver = removeserver,
985 get_backend = get_backend,
986 changesettings = changesettings,