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 -- luacheck: ignore 212/self 431/err 211/ret
  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_QUEUE          = 128,  -- might influence the length of the pending sockets queue
  28         ACCEPT_DELAY          = 10,  -- seconds to wait until the next attempt of a full server to accept
  29         READ_TIMEOUT          = 60 * 60 * 6,  -- timeout in seconds for read data from socket
  30         WRITE_TIMEOUT         = 180,  -- timeout in seconds for write data on socket
  31         CONNECT_TIMEOUT       = 20,  -- timeout in seconds for connection attempts
  32         CLEAR_DELAY           = 5,  -- seconds to wait for clearing interface list (and calling ondisconnect listeners)
  33         DEBUG                 = true,  -- show debug messages
  34 }
  35
  36 local pairs = pairs
  37 local select = select
  38 local require = require
  39 local tostring = tostring
  40 local setmetatable = setmetatable
  41
  42 local t_insert = table.insert
  43 local t_concat = table.concat
  44 local s_sub = string.sub
  45
  46 local coroutine_wrap = coroutine.wrap
  47 local coroutine_yield = coroutine.yield
  48
  49 local has_luasec, ssl = pcall ( require , "ssl" )
  50 local socket = require "socket"
  51 local levent = require "luaevent.core"
  52
  53 local socket_gettime = socket.gettime
  54 local getaddrinfo = socket.dns.getaddrinfo
  55
  56 local log = require ("util.logger").init("socket")
  57
  58 local function debug(...)
  59         return log("debug", ("%s "):rep(select('#', ...)), ...)
  60 end
  61 -- local vdebug = debug;
  62
  63 local bitor = ( function( ) -- thx Rici Lake
  64         local hasbit = function( x, p )
  65                 return x % ( p + p ) >= p
  66         end
  67         return function( x, y )
  68                 local p = 1
  69                 local z = 0
  70                 local limit = x > y and x or y
  71                 while p <= limit do
  72                         if hasbit( x, p ) or hasbit( y, p ) then
  73                                 z = z + p
  74                         end
  75                         p = p + p
  76                 end
  77                 return z
  78         end
  79 end )( )
  80
  81 local base = levent.new( )
  82 local addevent = base.addevent
  83 local EV_READ = levent.EV_READ
  84 local EV_WRITE = levent.EV_WRITE
  85 local EV_TIMEOUT = levent.EV_TIMEOUT
  86 local EV_SIGNAL = levent.EV_SIGNAL
  87
  88 local EV_READWRITE = bitor( EV_READ, EV_WRITE )
  89
  90 local interfacelist = { }
  91
  92 -- Client interface methods
  93 local interface_mt = {}; interface_mt.__index = interface_mt;
  94
  95 -- Private methods
  96 function interface_mt:_close()
  97         return self:_destroy();
  98 end
  99
 100 function interface_mt:_start_connection(plainssl) -- called from wrapclient
 101         local callback = function( event )
 102                 if EV_TIMEOUT == event then  -- timeout during connection
 103                         self.fatalerror = "connection timeout"
 104                         self:ontimeout()  -- call timeout listener
 105                         self:_close()
 106                         debug( "new connection failed. id:", self.id, "error:", self.fatalerror )
 107                 else
 108                         if plainssl and has_luasec then  -- start ssl session
 109                                 self:starttls(self._sslctx, true)
 110                         else  -- normal connection
 111                                 self:_start_session(true)
 112                         end
 113                         debug( "new connection established. id:", self.id )
 114                 end
 115                 self.eventconnect = nil
 116                 return -1
 117         end
 118         self.eventconnect = addevent( base, self.conn, EV_WRITE, callback, cfg.CONNECT_TIMEOUT )
 119         return true
 120 end
 121 function interface_mt:_start_session(call_onconnect) -- new session, for example after startssl
 122         if self.type == "client" then
 123                 local callback = function( )
 124                         self:_lock( false,  false, false )
 125                         --vdebug( "start listening on client socket with id:", self.id )
 126                         self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
 127                         if call_onconnect then
 128                                 self:onconnect()
 129                         end
 130                         self.eventsession = nil
 131                         return -1
 132                 end
 133                 self.eventsession = addevent( base, nil, EV_TIMEOUT, callback, 0 )
 134         else
 135                 self:_lock( false )
 136                 --vdebug( "start listening on server socket with id:", self.id )
 137                 self.eventread = addevent( base, self.conn, EV_READ, self.readcallback )  -- register callback
 138         end
 139         return true
 140 end
 141 function interface_mt:_start_ssl(call_onconnect) -- old socket will be destroyed, therefore we have to close read/write events first
 142         --vdebug( "starting ssl session with client id:", self.id )
 143         local _
 144         _ = self.eventread and self.eventread:close( )  -- close events; this must be called outside of the event callbacks!
 145         _ = self.eventwrite and self.eventwrite:close( )
 146         self.eventread, self.eventwrite = nil, nil
 147         local err
 148         self.conn, err = ssl.wrap( self.conn, self._sslctx )
 149         if err then
 150                 self.fatalerror = err
 151                 self.conn = nil  -- cannot be used anymore
 152                 if call_onconnect then
 153                         self.ondisconnect = nil  -- dont call this when client isnt really connected
 154                 end
 155                 self:_close()
 156                 debug( "fatal error while ssl wrapping:", err )
 157                 return false
 158         end
 159         self.conn:settimeout( 0 )  -- set non blocking
 160         local handshakecallback = coroutine_wrap(function( event )
 161                 local _, err
 162                 local attempt = 0
 163                 local maxattempt = cfg.MAX_HANDSHAKE_ATTEMPTS
 164                 while attempt < maxattempt do  -- no endless loop
 165                         attempt = attempt + 1
 166                         debug( "ssl handshake of client with id:"..tostring(self)..", attempt:"..attempt )
 167                         if attempt > maxattempt then
 168                                 self.fatalerror = "max handshake attempts exceeded"
 169                         elseif EV_TIMEOUT == event then
 170                                 self.fatalerror = "timeout during handshake"
 171                         else
 172                                 _, err = self.conn:dohandshake( )
 173                                 if not err then
 174                                         self:_lock( false, false, false )  -- unlock the interface; sending, closing etc allowed
 175                                         self.send = self.conn.send  -- caching table lookups with new client object
 176                                         self.receive = self.conn.receive
 177                                         if not call_onconnect then  -- trigger listener
 178                                                 self:onstatus("ssl-handshake-complete");
 179                                         end
 180                                         self:_start_session( call_onconnect )
 181                                         debug( "ssl handshake done" )
 182                                         self.eventhandshake = nil
 183                                         return -1
 184                                 end
 185                                 if err == "wantwrite" then
 186                                         event = EV_WRITE
 187                                 elseif err == "wantread" then
 188                                         event = EV_READ
 189                                 else
 190                                         debug( "ssl handshake error:", err )
 191                                         self.fatalerror = err
 192                                 end
 193                         end
 194                         if self.fatalerror then
 195                                 if call_onconnect then
 196                                         self.ondisconnect = nil  -- dont call this when client isnt really connected
 197                                 end
 198                                 self:_close()
 199                                 debug( "handshake failed because:", self.fatalerror )
 200                                 self.eventhandshake = nil
 201                                 return -1
 202                         end
 203                         event = coroutine_yield( event, cfg.HANDSHAKE_TIMEOUT )  -- yield this monster...
 204                 end
 205         end
 206         )
 207         debug "starting handshake..."
 208         self:_lock( false, true, true )  -- unlock read/write events, but keep interface locked
 209         self.eventhandshake = addevent( base, self.conn, EV_READWRITE, handshakecallback, cfg.HANDSHAKE_TIMEOUT )
 210         return true
 211 end
 212 function interface_mt:_destroy()  -- close this interface + events and call last listener
 213         debug( "closing client with id:", self.id, self.fatalerror )
 214         self:_lock( true, true, true )  -- first of all, lock the interface to avoid further actions
 215         local _
 216         _ = self.eventread and self.eventread:close( )
 217         if self.type == "client" then
 218                 _ = self.eventwrite and self.eventwrite:close( )
 219                 _ = self.eventhandshake and self.eventhandshake:close( )
 220                 _ = self.eventstarthandshake and self.eventstarthandshake:close( )
 221                 _ = self.eventconnect and self.eventconnect:close( )
 222                 _ = self.eventsession and self.eventsession:close( )
 223                 _ = self.eventwritetimeout and self.eventwritetimeout:close( )
 224                 _ = self.eventreadtimeout and self.eventreadtimeout:close( )
 225                 _ = 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)
 226                 _ = self.conn and self.conn:close( ) -- close connection
 227                 _ = self._server and self._server:counter(-1);
 228                 self.eventread, self.eventwrite = nil, nil
 229                 self.eventstarthandshake, self.eventhandshake, self.eventclose = nil, nil, nil
 230                 self.readcallback, self.writecallback = nil, nil
 231         else
 232                 self.conn:close( )
 233                 self.eventread, self.eventclose = nil, nil
 234                 self.interface, self.readcallback = nil, nil
 235         end
 236         interfacelist[ self ] = nil
 237         return true
 238 end
 239
 240 function interface_mt:_lock(nointerface, noreading, nowriting)  -- lock or unlock this interface or events
 241         self.nointerface, self.noreading, self.nowriting = nointerface, noreading, nowriting
 242         return nointerface, noreading, nowriting
 243 end
 244
 245 --TODO: Deprecate
 246 function interface_mt:lock_read(switch)
 247         if switch then
 248                 return self:pause();
 249         else
 250                 return self:resume();
 251         end
 252 end
 253
 254 function interface_mt:pause()
 255         return self:_lock(self.nointerface, true, self.nowriting);
 256 end
 257
 258 function interface_mt:resume()
 259         self:_lock(self.nointerface, false, self.nowriting);
 260         if self.readcallback and not self.eventread then
 261                 self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
 262                 return true;
 263         end
 264 end
 265
 266 function interface_mt:counter(c)
 267         if c then
 268                 self._connections = self._connections + c
 269         end
 270         return self._connections
 271 end
 272
 273 -- Public methods
 274 function interface_mt:write(data)
 275         if self.nowriting then return nil, "locked" end
 276         --vdebug( "try to send data to client, id/data:", self.id, data )
 277         data = tostring( data )
 278         local len = #data
 279         local total = len + self.writebufferlen
 280         if total > cfg.MAX_SEND_LENGTH then  -- check buffer length
 281                 local err = "send buffer exceeded"
 282                 debug( "error:", err )  -- to much, check your app
 283                 return nil, err
 284         end
 285         t_insert(self.writebuffer, data) -- new buffer
 286         self.writebufferlen = total
 287         if not self.eventwrite then  -- register new write event
 288                 --vdebug( "register new write event" )
 289                 self.eventwrite = addevent( base, self.conn, EV_WRITE, self.writecallback, cfg.WRITE_TIMEOUT )
 290         end
 291         return true
 292 end
 293 function interface_mt:close()
 294         if self.nointerface then return nil, "locked"; end
 295         debug( "try to close client connection with id:", self.id )
 296         if self.type == "client" then
 297                 self.fatalerror = "client to close"
 298                 if self.eventwrite then -- wait for incomplete write request
 299                         self:_lock( true, true, false )
 300                         debug "closing delayed until writebuffer is empty"
 301                         return nil, "writebuffer not empty, waiting"
 302                 else -- close now
 303                         self:_lock( true, true, true )
 304                         self:_close()
 305                         return true
 306                 end
 307         else
 308                 debug( "try to close server with id:", tostring(self.id))
 309                 self.fatalerror = "server to close"
 310                 self:_lock( true )
 311                 self:_close( 0 )
 312                 return true
 313         end
 314 end
 315
 316 function interface_mt:socket()
 317         return self.conn
 318 end
 319
 320 function interface_mt:server()
 321         return self._server or self;
 322 end
 323
 324 function interface_mt:port()
 325         return self._port
 326 end
 327
 328 function interface_mt:serverport()
 329         return self._serverport
 330 end
 331
 332 function interface_mt:ip()
 333         return self._ip
 334 end
 335
 336 function interface_mt:ssl()
 337         return self._usingssl
 338 end
 339 interface_mt.clientport = interface_mt.port -- COMPAT server_select
 340
 341 function interface_mt:type()
 342         return self._type or "client"
 343 end
 344
 345 function interface_mt:connections()
 346         return self._connections
 347 end
 348
 349 function interface_mt:address()
 350         return self.addr
 351 end
 352
 353 function interface_mt:set_sslctx(sslctx)
 354         self._sslctx = sslctx;
 355         if sslctx then
 356                 self.starttls = nil; -- use starttls() of interface_mt
 357         else
 358                 self.starttls = false; -- prevent starttls()
 359         end
 360 end
 361
 362 function interface_mt:set_mode(pattern)
 363         if pattern then
 364                 self._pattern = pattern;
 365         end
 366         return self._pattern;
 367 end
 368
 369 function interface_mt:set_send(new_send) -- luacheck: ignore 212
 370         -- No-op, we always use the underlying connection's send
 371 end
 372
 373 function interface_mt:starttls(sslctx, call_onconnect)
 374         debug( "try to start ssl at client id:", self.id )
 375         local err
 376         self._sslctx = sslctx;
 377         if self._usingssl then  -- startssl was already called
 378                 err = "ssl already active"
 379         end
 380         if err then
 381                 debug( "error:", err )
 382                 return nil, err
 383         end
 384         self._usingssl = true
 385         self.startsslcallback = function( )  -- we have to start the handshake outside of a read/write event
 386                 self.startsslcallback = nil
 387                 self:_start_ssl(call_onconnect);
 388                 self.eventstarthandshake = nil
 389                 return -1
 390         end
 391         if not self.eventwrite then
 392                 self:_lock( true, true, true )  -- lock the interface, to not disturb the handshake
 393                 self.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, self.startsslcallback, 0 )  -- add event to start handshake
 394         else
 395                 -- wait until writebuffer is empty
 396                 self:_lock( true, true, false )
 397                 debug "ssl session delayed until writebuffer is empty..."
 398         end
 399         self.starttls = false;
 400         return true
 401 end
 402
 403 function interface_mt:setoption(option, value)
 404         if self.conn.setoption then
 405                 return self.conn:setoption(option, value);
 406         end
 407         return false, "setoption not implemented";
 408 end
 409
 410 function interface_mt:setlistener(listener)
 411         self:ondetach(); -- Notify listener that it is no longer responsible for this connection
 412         self.onconnect = listener.onconnect;
 413         self.ondisconnect = listener.ondisconnect;
 414         self.onincoming = listener.onincoming;
 415         self.ontimeout = listener.ontimeout;
 416         self.onreadtimeout = listener.onreadtimeout;
 417         self.onstatus = listener.onstatus;
 418         self.ondetach = listener.ondetach;
 419 end
 420
 421 -- Stub handlers
 422 function interface_mt:onconnect()
 423 end
 424 function interface_mt:onincoming()
 425 end
 426 function interface_mt:ondisconnect()
 427 end
 428 function interface_mt:ontimeout()
 429 end
 430 function interface_mt:onreadtimeout()
 431         self.fatalerror = "timeout during receiving"
 432         debug( "connection failed:", self.fatalerror )
 433         self:_close()
 434         self.eventread = nil
 435 end
 436 function interface_mt:ondrain()
 437 end
 438 function interface_mt:ondetach()
 439 end
 440 function interface_mt:onstatus()
 441 end
 442
 443 -- End of client interface methods
 444
 445 local function handleclient( client, ip, port, server, pattern, listener, sslctx )  -- creates an client interface
 446         --vdebug("creating client interfacce...")
 447         local interface = {
 448                 type = "client";
 449                 conn = client;
 450                 currenttime = socket_gettime( );  -- safe the origin
 451                 writebuffer = {};  -- writebuffer
 452                 writebufferlen = 0;  -- length of writebuffer
 453                 send = client.send;  -- caching table lookups
 454                 receive = client.receive;
 455                 onconnect = listener.onconnect;  -- will be called when client disconnects
 456                 ondisconnect = listener.ondisconnect;  -- will be called when client disconnects
 457                 onincoming = listener.onincoming;  -- will be called when client sends data
 458                 ontimeout = listener.ontimeout; -- called when fatal socket timeout occurs
 459                 onreadtimeout = listener.onreadtimeout; -- called when socket inactivity timeout occurs
 460                 ondrain = listener.ondrain; -- called when writebuffer is empty
 461                 ondetach = listener.ondetach; -- called when disassociating this listener from this connection
 462                 onstatus = listener.onstatus; -- called for status changes (e.g. of SSL/TLS)
 463                 eventread = false, eventwrite = false, eventclose = false,
 464                 eventhandshake = false, eventstarthandshake = false;  -- event handler
 465                 eventconnect = false, eventsession = false;  -- more event handler...
 466                 eventwritetimeout = false;  -- even more event handler...
 467                 eventreadtimeout = false;
 468                 fatalerror = false;  -- error message
 469                 writecallback = false;  -- will be called on write events
 470                 readcallback = false;  -- will be called on read events
 471                 nointerface = true;  -- lock/unlock parameter of this interface
 472                 noreading = false, nowriting = false;  -- locks of the read/writecallback
 473                 startsslcallback = false;  -- starting handshake callback
 474                 position = false;  -- position of client in interfacelist
 475
 476                 -- Properties
 477                 _ip = ip, _port = port, _server = server, _pattern = pattern,
 478                 _serverport = (server and server:port() or nil),
 479                 _sslctx = sslctx; -- parameters
 480                 _usingssl = false;  -- client is using ssl;
 481         }
 482         if not has_luasec then interface.starttls = false; end
 483         interface.id = tostring(interface):match("%x+$");
 484         interface.writecallback = function( event )  -- called on write events
 485                 --vdebug( "new client write event, id/ip/port:", interface, ip, port )
 486                 if interface.nowriting or ( interface.fatalerror and ( "client to close" ~= interface.fatalerror ) ) then  -- leave this event
 487                         --vdebug( "leaving this event because:", interface.nowriting or interface.fatalerror )
 488                         interface.eventwrite = false
 489                         return -1
 490                 end
 491                 if EV_TIMEOUT == event then  -- took too long to write some data to socket -> disconnect
 492                         interface.fatalerror = "timeout during writing"
 493                         debug( "writing failed:", interface.fatalerror )
 494                         interface:_close()
 495                         interface.eventwrite = false
 496                         return -1
 497                 else  -- can write :)
 498                         if interface._usingssl then  -- handle luasec
 499                                 if interface.eventreadtimeout then  -- we have to read first
 500                                         local ret = interface.readcallback( )  -- call readcallback
 501                                         --vdebug( "tried to read in writecallback, result:", ret )
 502                                 end
 503                                 if interface.eventwritetimeout then  -- luasec only
 504                                         interface.eventwritetimeout:close( )  -- first we have to close timeout event which where regged after a wantread error
 505                                         interface.eventwritetimeout = false
 506                                 end
 507                         end
 508                         interface.writebuffer = { t_concat(interface.writebuffer) }
 509                         local succ, err, byte = interface.conn:send( interface.writebuffer[1], 1, interface.writebufferlen )
 510                         --vdebug( "write data:", interface.writebuffer, "error:", err, "part:", byte )
 511                         if succ then  -- writing succesful
 512                                 interface.writebuffer[1] = nil
 513                                 interface.writebufferlen = 0
 514                                 interface:ondrain();
 515                                 if interface.fatalerror then
 516                                         debug "closing client after writing"
 517                                         interface:_close()  -- close interface if needed
 518                                 elseif interface.startsslcallback then  -- start ssl connection if needed
 519                                         debug "starting ssl handshake after writing"
 520                                         interface.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, interface.startsslcallback, 0 )
 521                                 elseif interface.writebufferlen ~= 0 then
 522                                         -- data possibly written from ondrain
 523                                         return EV_WRITE, cfg.WRITE_TIMEOUT
 524                                 elseif interface.eventreadtimeout then
 525                                         return EV_WRITE, cfg.WRITE_TIMEOUT
 526                                 end
 527                                 interface.eventwrite = nil
 528                                 return -1
 529                         elseif byte and (err == "timeout" or err == "wantwrite") then  -- want write again
 530                                 --vdebug( "writebuffer is not empty:", err )
 531                                 interface.writebuffer[1] = s_sub( interface.writebuffer[1], byte + 1, interface.writebufferlen )  -- new buffer
 532                                 interface.writebufferlen = interface.writebufferlen - byte
 533                                 if "wantread" == err then  -- happens only with luasec
 534                                         local callback = function( )
 535                                                 interface:_close()
 536                                                 interface.eventwritetimeout = nil
 537                                                 return -1;
 538                                         end
 539                                         interface.eventwritetimeout = addevent( base, nil, EV_TIMEOUT, callback, cfg.WRITE_TIMEOUT )  -- reg a new timeout event
 540                                         debug( "wantread during write attempt, reg it in readcallback but dont know what really happens next..." )
 541                                         -- hopefully this works with luasec; its simply not possible to use 2 different write events on a socket in luaevent
 542                                         return -1
 543                                 end
 544                                 return EV_WRITE, cfg.WRITE_TIMEOUT
 545                         else  -- connection was closed during writing or fatal error
 546                                 interface.fatalerror = err or "fatal error"
 547                                 debug( "connection failed in write event:", interface.fatalerror )
 548                                 interface:_close()
 549                                 interface.eventwrite = nil
 550                                 return -1
 551                         end
 552                 end
 553         end
 554
 555         interface.readcallback = function( event )  -- called on read events
 556                 --vdebug( "new client read event, id/ip/port:", tostring(interface.id), tostring(ip), tostring(port) )
 557                 if interface.noreading or interface.fatalerror then  -- leave this event
 558                         --vdebug( "leaving this event because:", tostring(interface.noreading or interface.fatalerror) )
 559                         interface.eventread = nil
 560                         return -1
 561                 end
 562                 if EV_TIMEOUT == event and interface:onreadtimeout() ~= true then
 563                         return -1 -- took too long to get some data from client -> disconnect
 564                 end
 565                 if interface._usingssl then  -- handle luasec
 566                         if interface.eventwritetimeout then  -- ok, in the past writecallback was regged
 567                                 local ret = interface.writecallback( )  -- call it
 568                                 --vdebug( "tried to write in readcallback, result:", tostring(ret) )
 569                         end
 570                         if interface.eventreadtimeout then
 571                                 interface.eventreadtimeout:close( )
 572                                 interface.eventreadtimeout = nil
 573                         end
 574                 end
 575                 local buffer, err, part = interface.conn:receive( interface._pattern )  -- receive buffer with "pattern"
 576                 --vdebug( "read data:", tostring(buffer), "error:", tostring(err), "part:", tostring(part) )
 577                 buffer = buffer or part
 578                 if buffer and #buffer > cfg.MAX_READ_LENGTH then  -- check buffer length
 579                         interface.fatalerror = "receive buffer exceeded"
 580                         debug( "fatal error:", interface.fatalerror )
 581                         interface:_close()
 582                         interface.eventread = nil
 583                         return -1
 584                 end
 585                 if err and ( err ~= "timeout" and err ~= "wantread" ) then
 586                         if "wantwrite" == err then -- need to read on write event
 587                                 if not interface.eventwrite then  -- register new write event if needed
 588                                         interface.eventwrite = addevent( base, interface.conn, EV_WRITE, interface.writecallback, cfg.WRITE_TIMEOUT )
 589                                 end
 590                                 interface.eventreadtimeout = addevent( base, nil, EV_TIMEOUT,
 591                                 function( )
 592                                         interface:_close()
 593                                 end, cfg.READ_TIMEOUT
 594                                 )
 595                                 debug( "wantwrite during read attempt, reg it in writecallback but dont know what really happens next..." )
 596                                 -- to be honest i dont know what happens next, if it is allowed to first read, the write etc...
 597                         else  -- connection was closed or fatal error
 598                                 interface.fatalerror = err
 599                                 debug( "connection failed in read event:", interface.fatalerror )
 600                                 interface:_close()
 601                                 interface.eventread = nil
 602                                 return -1
 603                         end
 604                 else
 605                         interface.onincoming( interface, buffer, err )  -- send new data to listener
 606                 end
 607                 if interface.noreading then
 608                         interface.eventread = nil;
 609                         return -1;
 610                 end
 611                 return EV_READ, cfg.READ_TIMEOUT
 612         end
 613
 614         client:settimeout( 0 )  -- set non blocking
 615         setmetatable(interface, interface_mt)
 616         interfacelist[ interface ] = true  -- add to interfacelist
 617         return interface
 618 end
 619
 620 local function handleserver( server, addr, port, pattern, listener, sslctx )  -- creates an server interface
 621         debug "creating server interface..."
 622         local interface = {
 623                 _connections = 0;
 624
 625                 type = "server";
 626                 conn = server;
 627                 onconnect = listener.onconnect;  -- will be called when new client connected
 628                 eventread = false;  -- read event handler
 629                 eventclose = false; -- close event handler
 630                 readcallback = false; -- read event callback
 631                 fatalerror = false; -- error message
 632                 nointerface = true;  -- lock/unlock parameter
 633
 634                 _ip = addr, _port = port, _pattern = pattern,
 635                 _sslctx = sslctx;
 636         }
 637         interface.id = tostring(interface):match("%x+$");
 638         interface.readcallback = function( event )  -- server handler, called on incoming connections
 639                 --vdebug( "server can accept, id/addr/port:", interface, addr, port )
 640                 if interface.fatalerror then
 641                         --vdebug( "leaving this event because:", self.fatalerror )
 642                         interface.eventread = nil
 643                         return -1
 644                 end
 645                 local delay = cfg.ACCEPT_DELAY
 646                 if EV_TIMEOUT == event then
 647                         if interface._connections >= cfg.MAX_CONNECTIONS then  -- check connection count
 648                                 debug( "to many connections, seconds to wait for next accept:", delay )
 649                                 return EV_TIMEOUT, delay  -- timeout...
 650                         else
 651                                 return EV_READ  -- accept again
 652                         end
 653                 end
 654                 --vdebug("max connection check ok, accepting...")
 655                 local client, err = server:accept()    -- try to accept; TODO: check err
 656                 while client do
 657                         if interface._connections >= cfg.MAX_CONNECTIONS then
 658                                 client:close( )  -- refuse connection
 659                                 debug( "maximal connections reached, refuse client connection; accept delay:", delay )
 660                                 return EV_TIMEOUT, delay  -- delay for next accept attempt
 661                         end
 662                         local client_ip, client_port = client:getpeername( )
 663                         interface._connections = interface._connections + 1  -- increase connection count
 664                         local clientinterface = handleclient( client, client_ip, client_port, interface, pattern, listener, sslctx )
 665                         --vdebug( "client id:", clientinterface, "startssl:", startssl )
 666                         if has_luasec and sslctx then
 667                                 clientinterface:starttls(sslctx, true)
 668                         else
 669                                 clientinterface:_start_session( true )
 670                         end
 671                         debug( "accepted incoming client connection from:", client_ip or "<unknown IP>", client_port or "<unknown port>", "to", port or "<unknown port>");
 672
 673                         client, err = server:accept()    -- try to accept again
 674                 end
 675                 return EV_READ
 676         end
 677
 678         server:settimeout( 0 )
 679         setmetatable(interface, interface_mt)
 680         interfacelist[ interface ] = true
 681         interface:_start_session()
 682         return interface
 683 end
 684
 685 local function addserver( addr, port, listener, pattern, sslctx, startssl )  -- TODO: check arguments
 686         --vdebug( "creating new tcp server with following parameters:", addr or "nil", port or "nil", sslctx or "nil", startssl or "nil")
 687         if sslctx and not has_luasec then
 688                 debug "fatal error: luasec not found"
 689                 return nil, "luasec not found"
 690         end
 691         local server, err = socket.bind( addr, port, cfg.ACCEPT_QUEUE )  -- create server socket
 692         if not server then
 693                 debug( "creating server socket on "..addr.." port "..port.." failed:", err )
 694                 return nil, err
 695         end
 696         local interface = handleserver( server, addr, port, pattern, listener, sslctx, startssl )  -- new server handler
 697         debug( "new server created with id:", tostring(interface))
 698         return interface
 699 end
 700
 701 local function wrapclient( client, ip, port, listeners, pattern, sslctx )
 702         local interface = handleclient( client, ip, port, nil, pattern, listeners, sslctx )
 703         interface:_start_connection(sslctx)
 704         return interface, client
 705         --function handleclient( client, ip, port, server, pattern, listener, _, sslctx )  -- creates an client interface
 706 end
 707
 708 local function addclient( addr, serverport, listener, pattern, sslctx, typ )
 709         if sslctx and not has_luasec then
 710                 debug "need luasec, but not available"
 711                 return nil, "luasec not found"
 712         end
 713         if not typ then
 714                 local addrinfo, err = getaddrinfo(addr)
 715                 if not addrinfo then return nil, err end
 716                 if addrinfo[1] and addrinfo[1].family == "inet6" then
 717                         typ = "tcp6"
 718                 else
 719                         typ = "tcp"
 720                 end
 721         end
 722         local create = socket[typ]
 723         if type( create ) ~= "function"  then
 724                 return nil, "invalid socket type"
 725         end
 726         local client, err = create()  -- creating new socket
 727         if not client then
 728                 debug( "cannot create socket:", err )
 729                 return nil, err
 730         end
 731         client:settimeout( 0 )  -- set nonblocking
 732         local res, err = client:connect( addr, serverport )  -- connect
 733         if res or ( err == "timeout" ) then
 734                 local ip, port = client:getsockname( )
 735                 local interface = wrapclient( client, ip, serverport, listener, pattern, sslctx )
 736                 debug( "new connection id:", interface.id )
 737                 return interface, err
 738         else
 739                 debug( "new connection failed:", err )
 740                 return nil, err
 741         end
 742 end
 743
 744 local function loop( )  -- starts the event loop
 745         base:loop( )
 746         return "quitting";
 747 end
 748
 749 local function newevent( ... )
 750         return addevent( base, ... )
 751 end
 752
 753 local function closeallservers ( arg )
 754         for item in pairs( interfacelist ) do
 755                 if item.type == "server" then
 756                         item:close( arg )
 757                 end
 758         end
 759 end
 760
 761 local function setquitting(yes)
 762         if yes then
 763                 -- Quit now
 764                 closeallservers();
 765                 base:loopexit();
 766         end
 767 end
 768
 769 local function get_backend()
 770         return base:method();
 771 end
 772
 773 -- We need to hold onto the events to stop them
 774 -- being garbage-collected
 775 local signal_events = {}; -- [signal_num] -> event object
 776 local function hook_signal(signal_num, handler)
 777         local function _handler()
 778                 local ret = handler();
 779                 if ret ~= false then -- Continue handling this signal?
 780                         return EV_SIGNAL; -- Yes
 781                 end
 782                 return -1; -- Close this event
 783         end
 784         signal_events[signal_num] = base:addevent(signal_num, EV_SIGNAL, _handler);
 785         return signal_events[signal_num];
 786 end
 787
 788 local function link(sender, receiver, buffersize)
 789         local sender_locked;
 790
 791         function receiver:ondrain()
 792                 if sender_locked then
 793                         sender:resume();
 794                         sender_locked = nil;
 795                 end
 796         end
 797
 798         function sender:onincoming(data)
 799                 receiver:write(data);
 800                 if receiver.writebufferlen >= buffersize then
 801                         sender_locked = true;
 802                         sender:pause();
 803                 end
 804         end
 805         sender:set_mode("*a");
 806 end
 807
 808 local function add_task(delay, callback)
 809         local event_handle;
 810         event_handle = base:addevent(nil, 0, function ()
 811                 local ret = callback(socket_gettime());
 812                 if ret then
 813                         return 0, ret;
 814                 elseif event_handle then
 815                         return -1;
 816                 end
 817         end
 818         , delay);
 819         return event_handle;
 820 end
 821
 822 return {
 823         cfg = cfg,
 824         base = base,
 825         loop = loop,
 826         link = link,
 827         event = levent,
 828         event_base = base,
 829         addevent = newevent,
 830         addserver = addserver,
 831         addclient = addclient,
 832         wrapclient = wrapclient,
 833         setquitting = setquitting,
 834         closeall = closeallservers,
 835         get_backend = get_backend,
 836         hook_signal = hook_signal,
 837         add_task = add_task,
 838
 839         __NAME = SCRIPT_NAME,
 840         __DATE = LAST_MODIFIED,
 841         __AUTHOR = SCRIPT_AUTHOR,
 842         __VERSION = SCRIPT_VERSION,
 843
 844 }