Merge 0.6->0.7
[prosody.git] / net / server_event.lua
1 --[[
2
3
4                         server.lua based on lua/libevent by blastbeat
5
6                         notes:
7                         -- when using luaevent, never register 2 or more EV_READ at one socket, same for EV_WRITE
8                         -- you cant even register a new EV_READ/EV_WRITE callback inside another one
9                         -- never call eventcallback:close( ) from inside eventcallback
10                         -- to do some of the above, use timeout events or something what will called from outside
11                         -- dont let garbagecollect eventcallbacks, as long they are running
12                         -- when using luasec, there are 4 cases of timeout errors: wantread or wantwrite during reading or writing
13
14 --]]
15
16 local SCRIPT_NAME           = "server_event.lua"
17 local SCRIPT_VERSION        = "0.05"
18 local SCRIPT_AUTHOR         = "blastbeat"
19 local LAST_MODIFIED         = "2009/11/20"
20
21 local cfg = {
22         MAX_CONNECTIONS       = 100000,  -- max per server connections (use "ulimit -n" on *nix)
23         MAX_HANDSHAKE_ATTEMPTS= 1000,  -- attempts to finish ssl handshake
24         HANDSHAKE_TIMEOUT     = 60,  -- timeout in seconds per handshake attempt
25         MAX_READ_LENGTH       = 1024 * 1024 * 1024 * 1024,  -- max bytes allowed to read from sockets
26         MAX_SEND_LENGTH       = 1024 * 1024 * 1024 * 1024,  -- max bytes size of write buffer (for writing on sockets)
27         ACCEPT_DELAY          = 10,  -- seconds to wait until the next attempt of a full server to accept
28         READ_TIMEOUT          = 60 * 60 * 6,  -- timeout in seconds for read data from socket
29         WRITE_TIMEOUT         = 180,  -- timeout in seconds for write data on socket
30         CONNECT_TIMEOUT       = 20,  -- timeout in seconds for connection attempts
31         CLEAR_DELAY           = 5,  -- seconds to wait for clearing interface list (and calling ondisconnect listeners)
32         DEBUG                 = true,  -- show debug messages
33 }
34
35 local function use(x) return rawget(_G, x); end
36 local print = use "print"
37 local pcall = use "pcall"
38 local ipairs = use "ipairs"
39 local string = use "string"
40 local select = use "select"
41 local require = use "require"
42 local tostring = use "tostring"
43 local coroutine = use "coroutine"
44 local setmetatable = use "setmetatable"
45
46 local ssl = use "ssl"
47 local socket = use "socket" or require "socket"
48
49 local log = require ("util.logger").init("socket")
50
51 local function debug(...)
52         return log("debug", ("%s "):rep(select('#', ...)), ...)
53 end
54 local vdebug = debug;
55
56 local bitor = ( function( ) -- thx Rici Lake
57         local hasbit = function( x, p )
58                 return x % ( p + p ) >= p
59         end
60         return function( x, y )
61                 local p = 1
62                 local z = 0
63                 local limit = x > y and x or y
64                 while p <= limit do
65                         if hasbit( x, p ) or hasbit( y, p ) then
66                                 z = z + p
67                         end
68                         p = p + p
69                 end
70                 return z
71         end
72 end )( )
73
74 local event = require "luaevent.core"
75 local base = event.new( )
76 local EV_READ = event.EV_READ
77 local EV_WRITE = event.EV_WRITE
78 local EV_TIMEOUT = event.EV_TIMEOUT
79 local EV_SIGNAL = event.EV_SIGNAL
80
81 local EV_READWRITE = bitor( EV_READ, EV_WRITE )
82
83 local interfacelist = ( function( )  -- holds the interfaces for sockets
84         local array = { }
85         local len = 0
86         return function( method, arg )
87                 if "add" == method then
88                         len = len + 1
89                         array[ len ] = arg
90                         arg:_position( len )
91                         return len
92                 elseif "delete" == method then
93                         if len <= 0 then
94                                 return nil, "array is already empty"
95                         end
96                         local position = arg:_position()  -- get position in array
97                         if position ~= len then
98                                 local interface = array[ len ]  -- get last interface
99                                 array[ position ] = interface  -- copy it into free position
100                                 array[ len ] = nil  -- free last position
101                                 interface:_position( position )  -- set new position in array
102                         else  -- free last position
103                                 array[ len ] = nil
104                         end
105                         len = len - 1
106                         return len
107                 else
108                         return array
109                 end
110         end
111 end )( )
112
113 -- Client interface methods
114 local interface_mt
115 do
116         interface_mt = {}; interface_mt.__index = interface_mt;
117         
118         local addevent = base.addevent
119         local coroutine_wrap, coroutine_yield = coroutine.wrap,coroutine.yield
120         local string_len = string.len
121         
122         -- Private methods
123         function interface_mt:_position(new_position)
124                         self.position = new_position or self.position
125                         return self.position;
126         end
127         function interface_mt:_close() -- regs event to start self:_destroy()
128                         local callback = function( )
129                                 self:_destroy();
130                                 self.eventclose = nil
131                                 return -1
132                         end
133                         self.eventclose = addevent( base, nil, EV_TIMEOUT, callback, 0 )
134                         return true
135         end
136         
137         function interface_mt:_start_connection(plainssl) -- should be called from addclient
138                         local callback = function( event )
139                                 if EV_TIMEOUT == event then  -- timeout during connection
140                                         self.fatalerror = "connection timeout"
141                                         self:ontimeout()  -- call timeout listener
142                                         self:_close()
143                                         debug( "new connection failed. id:", self.id, "error:", self.fatalerror )
144                                 else
145                                         if plainssl and ssl then  -- start ssl session
146                                                 self:starttls()
147                                         else  -- normal connection
148                                                 self:_start_session( self.listener.onconnect )
149                                         end
150                                         debug( "new connection established. id:", self.id )
151                                 end
152                                 self.eventconnect = nil
153                                 return -1
154                         end
155                         self.eventconnect = addevent( base, self.conn, EV_WRITE, callback, cfg.CONNECT_TIMEOUT )
156                         return true
157         end
158         function interface_mt:_start_session(onconnect) -- new session, for example after startssl
159                 if self.type == "client" then
160                         local callback = function( )
161                                 self:_lock( false,  false, false )
162                                 --vdebug( "start listening on client socket with id:", self.id )
163                                 self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
164                                 self:onconnect()
165                                 self.eventsession = nil
166                                 return -1
167                         end
168                         self.eventsession = addevent( base, nil, EV_TIMEOUT, callback, 0 )
169                 else
170                         self:_lock( false )
171                         --vdebug( "start listening on server socket with id:", self.id )
172                         self.eventread = addevent( base, self.conn, EV_READ, self.readcallback )  -- register callback
173                 end
174                 return true
175         end
176         function interface_mt:_start_ssl(arg) -- old socket will be destroyed, therefore we have to close read/write events first
177                         --vdebug( "starting ssl session with client id:", self.id )
178                         local _
179                         _ = self.eventread and self.eventread:close( )  -- close events; this must be called outside of the event callbacks!
180                         _ = self.eventwrite and self.eventwrite:close( )
181                         self.eventread, self.eventwrite = nil, nil
182                         local err
183                         self.conn, err = ssl.wrap( self.conn, self._sslctx )
184                         if err then
185                                 self.fatalerror = err
186                                 self.conn = nil  -- cannot be used anymore
187                                 if "onconnect" == arg then
188                                         self.ondisconnect = nil  -- dont call this when client isnt really connected
189                                 end
190                                 self:_close()
191                                 debug( "fatal error while ssl wrapping:", err )
192                                 return false
193                         end
194                         self.conn:settimeout( 0 )  -- set non blocking
195                         local handshakecallback = coroutine_wrap(
196                                 function( event )
197                                         local _, err
198                                         local attempt = 0
199                                         local maxattempt = cfg.MAX_HANDSHAKE_ATTEMPTS
200                                         while attempt < maxattempt do  -- no endless loop
201                                                 attempt = attempt + 1
202                                                 debug( "ssl handshake of client with id:"..tostring(self)..", attempt:"..attempt )
203                                                 if attempt > maxattempt then
204                                                         self.fatalerror = "max handshake attempts exceeded"
205                                                 elseif EV_TIMEOUT == event then
206                                                         self.fatalerror = "timeout during handshake"
207                                                 else
208                                                         _, err = self.conn:dohandshake( )
209                                                         if not err then
210                                                                 self:_lock( false, false, false )  -- unlock the interface; sending, closing etc allowed
211                                                                 self.send = self.conn.send  -- caching table lookups with new client object
212                                                                 self.receive = self.conn.receive
213                                                                 local onsomething
214                                                                 if "onconnect" == arg then  -- trigger listener
215                                                                         onsomething = self.onconnect
216                                                                 else
217                                                                         onsomething = self.onsslconnection
218                                                                 end
219                                                                 self:_start_session( onsomething )
220                                                                 debug( "ssl handshake done" )
221                                                                 self:onstatus("ssl-handshake-complete");
222                                                                 self.eventhandshake = nil
223                                                                 return -1
224                                                         end
225                                                         debug( "error during ssl handshake:", err )
226                                                         if err == "wantwrite" then
227                                                                 event = EV_WRITE
228                                                         elseif err == "wantread" then
229                                                                 event = EV_READ
230                                                         else
231                                                                 self.fatalerror = err
232                                                         end
233                                                 end
234                                                 if self.fatalerror then
235                                                         if "onconnect" == arg then
236                                                                 self.ondisconnect = nil  -- dont call this when client isnt really connected
237                                                         end
238                                                         self:_close()
239                                                         debug( "handshake failed because:", self.fatalerror )
240                                                         self.eventhandshake = nil
241                                                         return -1
242                                                 end
243                                                 event = coroutine_yield( event, cfg.HANDSHAKE_TIMEOUT )  -- yield this monster...
244                                         end
245                                 end
246                         )
247                         debug "starting handshake..."
248                         self:_lock( false, true, true )  -- unlock read/write events, but keep interface locked
249                         self.eventhandshake = addevent( base, self.conn, EV_READWRITE, handshakecallback, cfg.HANDSHAKE_TIMEOUT )
250                         return true
251         end
252         function interface_mt:_destroy()  -- close this interface + events and call last listener
253                         debug( "closing client with id:", self.id )
254                         self:_lock( true, true, true )  -- first of all, lock the interface to avoid further actions
255                         local _
256                         _ = self.eventread and self.eventread:close( )  -- close events; this must be called outside of the event callbacks!
257                         if self.type == "client" then
258                                 _ = self.eventwrite and self.eventwrite:close( )
259                                 _ = self.eventhandshake and self.eventhandshake:close( )
260                                 _ = self.eventstarthandshake and self.eventstarthandshake:close( )
261                                 _ = self.eventconnect and self.eventconnect:close( )
262                                 _ = self.eventsession and self.eventsession:close( )
263                                 _ = self.eventwritetimeout and self.eventwritetimeout:close( )
264                                 _ = self.eventreadtimeout and self.eventreadtimeout:close( )
265                                 _ = 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)
266                                 _ = self.conn and self.conn:close( ) -- close connection, must also be called outside of any socket registered events!
267                                 _ = self._server and self._server:counter(-1);
268                                 self.eventread, self.eventwrite = nil, nil
269                                 self.eventstarthandshake, self.eventhandshake, self.eventclose = nil, nil, nil
270                                 self.readcallback, self.writecallback = nil, nil
271                         else
272                                 self.conn:close( )
273                                 self.eventread, self.eventclose = nil, nil
274                                 self.interface, self.readcallback = nil, nil
275                         end
276                         interfacelist( "delete", self )
277                         return true
278         end
279         
280         function interface_mt:_lock(nointerface, noreading, nowriting)  -- lock or unlock this interface or events
281                         self.nointerface, self.noreading, self.nowriting = nointerface, noreading, nowriting
282                         return nointerface, noreading, nowriting
283         end
284         
285         --TODO: Deprecate
286         function interface_mt:lock_read(switch)
287                 if switch then
288                         return self:pause();
289                 else
290                         return self:resume();
291                 end
292         end
293
294         function interface_mt:pause()
295                 return self:_lock(self.nointerface, true, self.nowriting);
296         end
297
298         function interface_mt:resume()
299                 return self:_lock(self.nointerface, false, self.nowriting);
300         end
301
302         function interface_mt:counter(c)
303                 if c then
304                         self._connections = self._connections + c
305                 end
306                 return self._connections
307         end
308         
309         -- Public methods
310         function interface_mt:write(data)
311                 if self.nowriting then return nil, "locked" end
312                 --vdebug( "try to send data to client, id/data:", self.id, data )
313                 data = tostring( data )
314                 local len = string_len( data )
315                 local total = len + self.writebufferlen
316                 if total > cfg.MAX_SEND_LENGTH then  -- check buffer length
317                         local err = "send buffer exceeded"
318                         debug( "error:", err )  -- to much, check your app
319                         return nil, err
320                 end
321                 self.writebuffer = self.writebuffer .. data -- new buffer
322                 self.writebufferlen = total
323                 if not self.eventwrite then  -- register new write event
324                         --vdebug( "register new write event" )
325                         self.eventwrite = addevent( base, self.conn, EV_WRITE, self.writecallback, cfg.WRITE_TIMEOUT )
326                 end
327                 return true
328         end
329         function interface_mt:close(now)
330                 if self.nointerface then return nil, "locked"; end
331                 debug( "try to close client connection with id:", self.id )
332                 if self.type == "client" then
333                         self.fatalerror = "client to close"
334                         if ( not self.eventwrite ) or now then  -- try to close immediately
335                                 self:_lock( true, true, true )
336                                 self:_close()
337                                 return true
338                         else  -- wait for incomplete write request
339                                 self:_lock( true, true, false )
340                                 debug "closing delayed until writebuffer is empty"
341                                 return nil, "writebuffer not empty, waiting"
342                         end
343                 else
344                         debug( "try to close server with id:", self.id, "args:", now )
345                         self.fatalerror = "server to close"
346                         self:_lock( true )
347                         local count = 0
348                         for _, item in ipairs( interfacelist( ) ) do
349                                 if ( item.type ~= "server" ) and ( item._server == self ) then  -- client/server match
350                                         if item:close( now ) then  -- writebuffer was empty
351                                                 count = count + 1
352                                         end
353                                 end
354                         end
355                         local timeout = 0  -- dont wait for unfinished writebuffers of clients...
356                         if not now then
357                                 timeout = cfg.WRITE_TIMEOUT  -- ...or wait for it
358                         end
359                         self:_close( timeout )  -- add new event to remove the server interface
360                         debug( "seconds remained until server is closed:", timeout )
361                         return count  -- returns finished clients with empty writebuffer
362                 end
363         end
364         
365         function interface_mt:server()
366                 return self._server or self;
367         end
368         
369         function interface_mt:port()
370                 return self._port
371         end
372         
373         function interface_mt:serverport()
374                 return self._serverport
375         end
376         
377         function interface_mt:ip()
378                 return self._ip
379         end
380         
381         function interface_mt:ssl()
382                 return self._usingssl
383         end
384
385         function interface_mt:type()
386                 return self._type or "client"
387         end
388         
389         function interface_mt:connections()
390                 return self._connections
391         end
392         
393         function interface_mt:address()
394                 return self.addr
395         end
396         
397         function interface_mt:set_sslctx(sslctx)
398                 self._sslctx = sslctx;
399                 if sslctx then
400                         self.starttls = nil; -- use starttls() of interface_mt
401                 else
402                         self.starttls = false; -- prevent starttls()
403                 end
404         end
405
406         function interface_mt:set_mode(pattern)
407                 if pattern then
408                         self._pattern = pattern;
409                 end
410                 return self._pattern;
411         end
412         
413         function interface_mt:set_send(new_send)
414                 -- No-op, we always use the underlying connection's send
415         end
416         
417         function interface_mt:starttls(sslctx)
418                 debug( "try to start ssl at client id:", self.id )
419                 local err
420                 self._sslctx = sslctx;
421                 if self._usingssl then  -- startssl was already called
422                         err = "ssl already active"
423                 end
424                 if err then
425                         debug( "error:", err )
426                         return nil, err
427                 end
428                 self._usingssl = true
429                 self.startsslcallback = function( )  -- we have to start the handshake outside of a read/write event
430                         self.startsslcallback = nil
431                         self:_start_ssl();
432                         self.eventstarthandshake = nil
433                         return -1
434                 end
435                 if not self.eventwrite then
436                         self:_lock( true, true, true )  -- lock the interface, to not disturb the handshake
437                         self.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, self.startsslcallback, 0 )  -- add event to start handshake
438                 else  -- wait until writebuffer is empty
439                         self:_lock( true, true, false )
440                         debug "ssl session delayed until writebuffer is empty..."
441                 end
442                 self.starttls = false;
443                 return true
444         end
445         
446         function interface_mt:setoption(option, value)
447                 if self.conn.setoption then
448                         return self.conn:setoption(option, value);
449                 end
450                 return false, "setoption not implemented";
451         end
452         
453         function interface_mt:setlistener(listener)
454                 self.onconnect, self.ondisconnect, self.onincoming, self.ontimeout, self.onstatus
455                         = listener.onconnect, listener.ondisconnect, listener.onincoming, listener.ontimeout, listener.onstatus;
456         end
457         
458         -- Stub handlers
459         function interface_mt:onconnect()
460                 return self:onincoming(nil);
461         end
462         function interface_mt:onincoming()
463         end
464         function interface_mt:ondisconnect()
465         end
466         function interface_mt:ontimeout()
467         end
468         function interface_mt:ondrain()
469         end
470         function interface_mt:onstatus()
471                 debug("server.lua: Dummy onstatus()")
472         end
473 end
474
475 -- End of client interface methods
476
477 local handleclient;
478 do
479         local string_sub = string.sub  -- caching table lookups
480         local string_len = string.len
481         local addevent = base.addevent
482         local coroutine_wrap = coroutine.wrap
483         local socket_gettime = socket.gettime
484         local coroutine_yield = coroutine.yield
485         function handleclient( client, ip, port, server, pattern, listener, _, sslctx )  -- creates an client interface
486                 --vdebug("creating client interfacce...")
487                 local interface = {
488                         type = "client";
489                         conn = client;
490                         currenttime = socket_gettime( );  -- safe the origin
491                         writebuffer = "";  -- writebuffer
492                         writebufferlen = 0;  -- length of writebuffer
493                         send = client.send;  -- caching table lookups
494                         receive = client.receive;
495                         onconnect = listener.onconnect;  -- will be called when client disconnects
496                         ondisconnect = listener.ondisconnect;  -- will be called when client disconnects
497                         onincoming = listener.onincoming;  -- will be called when client sends data
498                         ontimeout = listener.ontimeout; -- called when fatal socket timeout occurs
499                         onstatus = listener.onstatus; -- called for status changes (e.g. of SSL/TLS)
500                         eventread = false, eventwrite = false, eventclose = false,
501                         eventhandshake = false, eventstarthandshake = false;  -- event handler
502                         eventconnect = false, eventsession = false;  -- more event handler...
503                         eventwritetimeout = false;  -- even more event handler...
504                         eventreadtimeout = false;
505                         fatalerror = false;  -- error message
506                         writecallback = false;  -- will be called on write events
507                         readcallback = false;  -- will be called on read events
508                         nointerface = true;  -- lock/unlock parameter of this interface
509                         noreading = false, nowriting = false;  -- locks of the read/writecallback
510                         startsslcallback = false;  -- starting handshake callback
511                         position = false;  -- position of client in interfacelist
512                         
513                         -- Properties
514                         _ip = ip, _port = port, _server = server, _pattern = pattern,
515                         _serverport = (server and server:port() or nil),
516                         _sslctx = sslctx; -- parameters
517                         _usingssl = false;  -- client is using ssl;
518                 }
519                 if not ssl then interface.starttls = false; end
520                 interface.id = tostring(interface):match("%x+$");
521                 interface.writecallback = function( event )  -- called on write events
522                         --vdebug( "new client write event, id/ip/port:", interface, ip, port )
523                         if interface.nowriting or ( interface.fatalerror and ( "client to close" ~= interface.fatalerror ) ) then  -- leave this event
524                                 --vdebug( "leaving this event because:", interface.nowriting or interface.fatalerror )
525                                 interface.eventwrite = false
526                                 return -1
527                         end
528                         if EV_TIMEOUT == event then  -- took too long to write some data to socket -> disconnect
529                                 interface.fatalerror = "timeout during writing"
530                                 debug( "writing failed:", interface.fatalerror )
531                                 interface:_close()
532                                 interface.eventwrite = false
533                                 return -1
534                         else  -- can write :)
535                                 if interface._usingssl then  -- handle luasec
536                                         if interface.eventreadtimeout then  -- we have to read first
537                                                 local ret = interface.readcallback( )  -- call readcallback
538                                                 --vdebug( "tried to read in writecallback, result:", ret )
539                                         end
540                                         if interface.eventwritetimeout then  -- luasec only
541                                                 interface.eventwritetimeout:close( )  -- first we have to close timeout event which where regged after a wantread error
542                                                 interface.eventwritetimeout = false
543                                         end
544                                 end
545                                 local succ, err, byte = interface.conn:send( interface.writebuffer, 1, interface.writebufferlen )
546                                 --vdebug( "write data:", interface.writebuffer, "error:", err, "part:", byte )
547                                 if succ then  -- writing succesful
548                                         interface.writebuffer = ""
549                                         interface.writebufferlen = 0
550                                         interface:ondrain();
551                                         if interface.fatalerror then
552                                                 debug "closing client after writing"
553                                                 interface:_close()  -- close interface if needed
554                                         elseif interface.startsslcallback then  -- start ssl connection if needed
555                                                 debug "starting ssl handshake after writing"
556                                                 interface.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, interface.startsslcallback, 0 )
557                                         elseif interface.eventreadtimeout then
558                                                 return EV_WRITE, EV_TIMEOUT
559                                         end
560                                         interface.eventwrite = nil
561                                         return -1
562                                 elseif byte and (err == "timeout" or err == "wantwrite") then  -- want write again
563                                         --vdebug( "writebuffer is not empty:", err )
564                                         interface.writebuffer = string_sub( interface.writebuffer, byte + 1, interface.writebufferlen )  -- new buffer
565                                         interface.writebufferlen = interface.writebufferlen - byte
566                                         if "wantread" == err then  -- happens only with luasec
567                                                 local callback = function( )
568                                                         interface:_close()
569                                                         interface.eventwritetimeout = nil
570                                                         return -1;
571                                                 end
572                                                 interface.eventwritetimeout = addevent( base, nil, EV_TIMEOUT, callback, cfg.WRITE_TIMEOUT )  -- reg a new timeout event
573                                                 debug( "wantread during write attempt, reg it in readcallback but dont know what really happens next..." )
574                                                 -- hopefully this works with luasec; its simply not possible to use 2 different write events on a socket in luaevent
575                                                 return -1
576                                         end
577                                         return EV_WRITE, cfg.WRITE_TIMEOUT
578                                 else  -- connection was closed during writing or fatal error
579                                         interface.fatalerror = err or "fatal error"
580                                         debug( "connection failed in write event:", interface.fatalerror )
581                                         interface:_close()
582                                         interface.eventwrite = nil
583                                         return -1
584                                 end
585                         end
586                 end
587                 
588                 interface.readcallback = function( event )  -- called on read events
589                         --vdebug( "new client read event, id/ip/port:", tostring(interface.id), tostring(ip), tostring(port) )
590                         if interface.noreading or interface.fatalerror then  -- leave this event
591                                 --vdebug( "leaving this event because:", tostring(interface.noreading or interface.fatalerror) )
592                                 interface.eventread = nil
593                                 return -1
594                         end
595                         if EV_TIMEOUT == event then  -- took too long to get some data from client -> disconnect
596                                 interface.fatalerror = "timeout during receiving"
597                                 debug( "connection failed:", interface.fatalerror )
598                                 interface:_close()
599                                 interface.eventread = nil
600                                 return -1
601                         else -- can read
602                                 if interface._usingssl then  -- handle luasec
603                                         if interface.eventwritetimeout then  -- ok, in the past writecallback was regged
604                                                 local ret = interface.writecallback( )  -- call it
605                                                 --vdebug( "tried to write in readcallback, result:", tostring(ret) )
606                                         end
607                                         if interface.eventreadtimeout then
608                                                 interface.eventreadtimeout:close( )
609                                                 interface.eventreadtimeout = nil
610                                         end
611                                 end
612                                 local buffer, err, part = interface.conn:receive( interface._pattern )  -- receive buffer with "pattern"
613                                 --vdebug( "read data:", tostring(buffer), "error:", tostring(err), "part:", tostring(part) )
614                                 buffer = buffer or part or ""
615                                 local len = string_len( buffer )
616                                 if len > cfg.MAX_READ_LENGTH then  -- check buffer length
617                                         interface.fatalerror = "receive buffer exceeded"
618                                         debug( "fatal error:", interface.fatalerror )
619                                         interface:_close()
620                                         interface.eventread = nil
621                                         return -1
622                                 end
623                                 interface.onincoming( interface, buffer, err )  -- send new data to listener
624                                 if err and ( err ~= "timeout" and err ~= "wantread" ) then
625                                         if "wantwrite" == err then -- need to read on write event
626                                                 if not interface.eventwrite then  -- register new write event if needed
627                                                         interface.eventwrite = addevent( base, interface.conn, EV_WRITE, interface.writecallback, cfg.WRITE_TIMEOUT )
628                                                 end
629                                                 interface.eventreadtimeout = addevent( base, nil, EV_TIMEOUT,
630                                                         function( )
631                                                                 interface:_close()
632                                                         end, cfg.READ_TIMEOUT
633                                                 )
634                                                 debug( "wantwrite during read attempt, reg it in writecallback but dont know what really happens next..." )
635                                                 -- to be honest i dont know what happens next, if it is allowed to first read, the write etc...
636                                         else  -- connection was closed or fatal error
637                                                 interface.fatalerror = err
638                                                 debug( "connection failed in read event:", interface.fatalerror )
639                                                 interface:_close()
640                                                 interface.eventread = nil
641                                                 return -1
642                                         end
643                                 end
644                                 return EV_READ, cfg.READ_TIMEOUT
645                         end
646                 end
647
648                 client:settimeout( 0 )  -- set non blocking
649                 setmetatable(interface, interface_mt)
650                 interfacelist( "add", interface )  -- add to interfacelist
651                 return interface
652         end
653 end
654
655 local handleserver
656 do
657         function handleserver( server, addr, port, pattern, listener, sslctx )  -- creates an server interface
658                 debug "creating server interface..."
659                 local interface = {
660                         _connections = 0;
661                         
662                         conn = server;
663                         onconnect = listener.onconnect;  -- will be called when new client connected
664                         eventread = false;  -- read event handler
665                         eventclose = false; -- close event handler
666                         readcallback = false; -- read event callback
667                         fatalerror = false; -- error message
668                         nointerface = true;  -- lock/unlock parameter
669                         
670                         _ip = addr, _port = port, _pattern = pattern,
671                         _sslctx = sslctx;
672                 }
673                 interface.id = tostring(interface):match("%x+$");
674                 interface.readcallback = function( event )  -- server handler, called on incoming connections
675                         --vdebug( "server can accept, id/addr/port:", interface, addr, port )
676                         if interface.fatalerror then
677                                 --vdebug( "leaving this event because:", self.fatalerror )
678                                 interface.eventread = nil
679                                 return -1
680                         end
681                         local delay = cfg.ACCEPT_DELAY
682                         if EV_TIMEOUT == event then
683                                 if interface._connections >= cfg.MAX_CONNECTIONS then  -- check connection count
684                                         debug( "to many connections, seconds to wait for next accept:", delay )
685                                         return EV_TIMEOUT, delay  -- timeout...
686                                 else
687                                         return EV_READ  -- accept again
688                                 end
689                         end
690                         --vdebug("max connection check ok, accepting...")
691                         local client, err = server:accept()    -- try to accept; TODO: check err
692                         while client do
693                                 if interface._connections >= cfg.MAX_CONNECTIONS then
694                                         client:close( )  -- refuse connection
695                                         debug( "maximal connections reached, refuse client connection; accept delay:", delay )
696                                         return EV_TIMEOUT, delay  -- delay for next accept attempt
697                                 end
698                                 local client_ip, client_port = client:getpeername( )
699                                 interface._connections = interface._connections + 1  -- increase connection count
700                                 local clientinterface = handleclient( client, client_ip, client_port, interface, pattern, listener, nil, sslctx )
701                                 --vdebug( "client id:", clientinterface, "startssl:", startssl )
702                                 if ssl and sslctx then
703                                         clientinterface:starttls(sslctx)
704                                 else
705                                         clientinterface:_start_session( clientinterface.onconnect )
706                                 end
707                                 debug( "accepted incoming client connection from:", client_ip or "<unknown IP>", client_port or "<unknown port>", "to", port or "<unknown port>");
708                                 
709                                 client, err = server:accept()    -- try to accept again
710                         end
711                         return EV_READ
712                 end
713                 
714                 server:settimeout( 0 )
715                 setmetatable(interface, interface_mt)
716                 interfacelist( "add", interface )
717                 interface:_start_session()
718                 return interface
719         end
720 end
721
722 local addserver = ( function( )
723         return function( addr, port, listener, pattern, sslcfg, startssl )  -- TODO: check arguments
724                 --vdebug( "creating new tcp server with following parameters:", addr or "nil", port or "nil", sslcfg or "nil", startssl or "nil")
725                 local server, err = socket.bind( addr, port, cfg.ACCEPT_QUEUE )  -- create server socket
726                 if not server then
727                         debug( "creating server socket failed because:", err )
728                         return nil, err
729                 end
730                 local sslctx
731                 if sslcfg then
732                         if not ssl then
733                                 debug "fatal error: luasec not found"
734                                 return nil, "luasec not found"
735                         end
736                         sslctx, err = sslcfg
737                         if err then
738                                 debug( "error while creating new ssl context for server socket:", err )
739                                 return nil, err
740                         end
741                 end
742                 local interface = handleserver( server, addr, port, pattern, listener, sslctx, startssl )  -- new server handler
743                 debug( "new server created with id:", tostring(interface))
744                 return interface
745         end
746 end )( )
747
748 local addclient, wrapclient
749 do
750         function wrapclient( client, ip, port, listeners, pattern, sslctx, startssl )
751                 local interface = handleclient( client, ip, port, nil, pattern, listeners, sslctx )
752                 interface:_start_session()
753                 return interface, client
754                 --function handleclient( client, ip, port, server, pattern, listener, _, sslctx )  -- creates an client interface
755         end
756         
757         function addclient( addr, serverport, listener, pattern, localaddr, localport, sslcfg, startssl )
758                 local client, err = socket.tcp()  -- creating new socket
759                 if not client then
760                         debug( "cannot create socket:", err )
761                         return nil, err
762                 end
763                 client:settimeout( 0 )  -- set nonblocking
764                 if localaddr then
765                         local res, err = client:bind( localaddr, localport, -1 )
766                         if not res then
767                                 debug( "cannot bind client:", err )
768                                 return nil, err
769                         end
770                 end
771                 local sslctx
772                 if sslcfg then  -- handle ssl/new context
773                         if not ssl then
774                                 debug "need luasec, but not available"
775                                 return nil, "luasec not found"
776                         end
777                         sslctx, err = sslcfg
778                         if err then
779                                 debug( "cannot create new ssl context:", err )
780                                 return nil, err
781                         end
782                 end
783                 local res, err = client:connect( addr, serverport )  -- connect
784                 if res or ( err == "timeout" ) then
785                         local ip, port = client:getsockname( )
786                         local server = function( )
787                                 return nil, "this is a dummy server interface"
788                         end
789                         local interface = wrapclient( client, ip, serverport, listener, pattern, sslctx, startssl )
790                         interface:_start_connection( startssl )
791                         debug( "new connection id:", interface.id )
792                         return interface, err
793                 else
794                         debug( "new connection failed:", err )
795                         return nil, err
796                 end
797         end
798 end
799
800
801 local loop = function( )  -- starts the event loop
802         base:loop( )
803         return "quitting";
804 end
805
806 local newevent = ( function( )
807         local add = base.addevent
808         return function( ... )
809                 return add( base, ... )
810         end
811 end )( )
812
813 local closeallservers = function( arg )
814         for _, item in ipairs( interfacelist( ) ) do
815                 if item.type == "server" then
816                         item:close( arg )
817                 end
818         end
819 end
820
821 local function setquitting(yes)
822         if yes then
823                  -- Quit now
824                  closeallservers();
825                  base:loopexit();
826         end
827 end
828
829 function get_backend()
830         return base:method();
831 end
832
833 -- We need to hold onto the events to stop them
834 -- being garbage-collected
835 local signal_events = {}; -- [signal_num] -> event object
836 function hook_signal(signal_num, handler)
837         local function _handler(event)
838                 local ret = handler();
839                 if ret ~= false then -- Continue handling this signal?
840                         return EV_SIGNAL; -- Yes
841                 end
842                 return -1; -- Close this event
843         end
844         signal_events[signal_num] = base:addevent(signal_num, EV_SIGNAL, _handler);
845         return signal_events[signal_num];
846 end
847
848 local function link(sender, receiver, buffersize)
849         sender:set_mode(buffersize);
850         local sender_locked;
851         
852         function receiver:ondrain()
853                 if sender_locked then
854                         sender:resume();
855                         sender_locked = nil;
856                 end
857         end
858         
859         function sender:onincoming(data)
860                 receiver:write(data);
861                 if receiver.writebufferlen >= buffersize then
862                         sender_locked = true;
863                         sender:pause();
864                 end
865         end
866 end
867
868 return {
869
870         cfg = cfg,
871         base = base,
872         loop = loop,
873         link = link,
874         event = event,
875         event_base = base,
876         addevent = newevent,
877         addserver = addserver,
878         addclient = addclient,
879         wrapclient = wrapclient,
880         setquitting = setquitting,
881         closeall = closeallservers,
882         get_backend = get_backend,
883         hook_signal = hook_signal,
884
885         __NAME = SCRIPT_NAME,
886         __DATE = LAST_MODIFIED,
887         __AUTHOR = SCRIPT_AUTHOR,
888         __VERSION = SCRIPT_VERSION,
889
890 }