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