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 not self.eventread then
 261                 self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
 262         end
 263 end
 264
 265 function interface_mt:counter(c)
 266         if c then
 267                 self._connections = self._connections + c
 268         end
 269         return self._connections
 270 end
 271
 272 -- Public methods
 273 function interface_mt:write(data)
 274         if self.nowriting then return nil, "locked" end
 275         --vdebug( "try to send data to client, id/data:", self.id, data )
 276         data = tostring( data )
 277         local len = #data
 278         local total = len + self.writebufferlen
 279         if total > cfg.MAX_SEND_LENGTH then  -- check buffer length
 280                 local err = "send buffer exceeded"
 281                 debug( "error:", err )  -- to much, check your app
 282                 return nil, err
 283         end
 284         t_insert(self.writebuffer, data) -- new buffer
 285         self.writebufferlen = total
 286         if not self.eventwrite then  -- register new write event
 287                 --vdebug( "register new write event" )
 288                 self.eventwrite = addevent( base, self.conn, EV_WRITE, self.writecallback, cfg.WRITE_TIMEOUT )
 289         end
 290         return true
 291 end
 292 function interface_mt:close()
 293         if self.nointerface then return nil, "locked"; end
 294         debug( "try to close client connection with id:", self.id )
 295         if self.type == "client" then
 296                 self.fatalerror = "client to close"
 297                 if self.eventwrite then -- wait for incomplete write request
 298                         self:_lock( true, true, false )
 299                         debug "closing delayed until writebuffer is empty"
 300                         return nil, "writebuffer not empty, waiting"
 301                 else -- close now
 302                         self:_lock( true, true, true )
 303                         self:_close()
 304                         return true
 305                 end
 306         else
 307                 debug( "try to close server with id:", tostring(self.id))
 308                 self.fatalerror = "server to close"
 309                 self:_lock( true )
 310                 self:_close( 0 )
 311                 return true
 312         end
 313 end
 314
 315 function interface_mt:socket()
 316         return self.conn
 317 end
 318
 319 function interface_mt:server()
 320         return self._server or self;
 321 end
 322
 323 function interface_mt:port()
 324         return self._port
 325 end
 326
 327 function interface_mt:serverport()
 328         return self._serverport
 329 end
 330
 331 function interface_mt:ip()
 332         return self._ip
 333 end
 334
 335 function interface_mt:ssl()
 336         return self._usingssl
 337 end
 338 interface_mt.clientport = interface_mt.port -- COMPAT server_select
 339
 340 function interface_mt:type()
 341         return self._type or "client"
 342 end
 343
 344 function interface_mt:connections()
 345         return self._connections
 346 end
 347
 348 function interface_mt:address()
 349         return self.addr
 350 end
 351
 352 function interface_mt:set_sslctx(sslctx)
 353         self._sslctx = sslctx;
 354         if sslctx then
 355                 self.starttls = nil; -- use starttls() of interface_mt
 356         else
 357                 self.starttls = false; -- prevent starttls()
 358         end
 359 end
 360
 361 function interface_mt:set_mode(pattern)
 362         if pattern then
 363                 self._pattern = pattern;
 364         end
 365         return self._pattern;
 366 end
 367
 368 function interface_mt:set_send(new_send) -- luacheck: ignore 212
 369         -- No-op, we always use the underlying connection's send
 370 end
 371
 372 function interface_mt:starttls(sslctx, call_onconnect)
 373         debug( "try to start ssl at client id:", self.id )
 374         local err
 375         self._sslctx = sslctx;
 376         if self._usingssl then  -- startssl was already called
 377                 err = "ssl already active"
 378         end
 379         if err then
 380                 debug( "error:", err )
 381                 return nil, err
 382         end
 383         self._usingssl = true
 384         self.startsslcallback = function( )  -- we have to start the handshake outside of a read/write event
 385                 self.startsslcallback = nil
 386                 self:_start_ssl(call_onconnect);
 387                 self.eventstarthandshake = nil
 388                 return -1
 389         end
 390         if not self.eventwrite then
 391                 self:_lock( true, true, true )  -- lock the interface, to not disturb the handshake
 392                 self.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, self.startsslcallback, 0 )  -- add event to start handshake
 393         else  -- wait until writebuffer is empty
 394                 self:_lock( true, true, false )
 395                 debug "ssl session delayed until writebuffer is empty..."
 396         end
 397         self.starttls = false;
 398         return true
 399 end
 400
 401 function interface_mt:setoption(option, value)
 402         if self.conn.setoption then
 403                 return self.conn:setoption(option, value);
 404         end
 405         return false, "setoption not implemented";
 406 end
 407
 408 function interface_mt:setlistener(listener)
 409         self:ondetach(); -- Notify listener that it is no longer responsible for this connection
 410         self.onconnect, self.ondisconnect, self.onincoming, self.ontimeout,
 411         self.onreadtimeout, self.onstatus, self.ondetach
 412                 = listener.onconnect, listener.ondisconnect, listener.onincoming, listener.ontimeout,
 413                   listener.onreadtimeout, listener.onstatus, listener.ondetach;
 414 end
 415
 416 -- Stub handlers
 417 function interface_mt:onconnect()
 418 end
 419 function interface_mt:onincoming()
 420 end
 421 function interface_mt:ondisconnect()
 422 end
 423 function interface_mt:ontimeout()
 424 end
 425 function interface_mt:onreadtimeout()
 426         self.fatalerror = "timeout during receiving"
 427         debug( "connection failed:", self.fatalerror )
 428         self:_close()
 429         self.eventread = nil
 430 end
 431 function interface_mt:ondrain()
 432 end
 433 function interface_mt:ondetach()
 434 end
 435 function interface_mt:onstatus()
 436 end
 437
 438 -- End of client interface methods
 439
 440 local function handleclient( client, ip, port, server, pattern, listener, sslctx )  -- creates an client interface
 441         --vdebug("creating client interfacce...")
 442         local interface = {
 443                 type = "client";
 444                 conn = client;
 445                 currenttime = socket_gettime( );  -- safe the origin
 446                 writebuffer = {};  -- writebuffer
 447                 writebufferlen = 0;  -- length of writebuffer
 448                 send = client.send;  -- caching table lookups
 449                 receive = client.receive;
 450                 onconnect = listener.onconnect;  -- will be called when client disconnects
 451                 ondisconnect = listener.ondisconnect;  -- will be called when client disconnects
 452                 onincoming = listener.onincoming;  -- will be called when client sends data
 453                 ontimeout = listener.ontimeout; -- called when fatal socket timeout occurs
 454                 onreadtimeout = listener.onreadtimeout; -- called when socket inactivity timeout occurs
 455                 ondrain = listener.ondrain; -- called when writebuffer is empty
 456                 ondetach = listener.ondetach; -- called when disassociating this listener from this connection
 457                 onstatus = listener.onstatus; -- called for status changes (e.g. of SSL/TLS)
 458                 eventread = false, eventwrite = false, eventclose = false,
 459                 eventhandshake = false, eventstarthandshake = false;  -- event handler
 460                 eventconnect = false, eventsession = false;  -- more event handler...
 461                 eventwritetimeout = false;  -- even more event handler...
 462                 eventreadtimeout = false;
 463                 fatalerror = false;  -- error message
 464                 writecallback = false;  -- will be called on write events
 465                 readcallback = false;  -- will be called on read events
 466                 nointerface = true;  -- lock/unlock parameter of this interface
 467                 noreading = false, nowriting = false;  -- locks of the read/writecallback
 468                 startsslcallback = false;  -- starting handshake callback
 469                 position = false;  -- position of client in interfacelist
 470
 471                 -- Properties
 472                 _ip = ip, _port = port, _server = server, _pattern = pattern,
 473                 _serverport = (server and server:port() or nil),
 474                 _sslctx = sslctx; -- parameters
 475                 _usingssl = false;  -- client is using ssl;
 476         }
 477         if not has_luasec then interface.starttls = false; end
 478         interface.id = tostring(interface):match("%x+$");
 479         interface.writecallback = function( event )  -- called on write events
 480                 --vdebug( "new client write event, id/ip/port:", interface, ip, port )
 481                 if interface.nowriting or ( interface.fatalerror and ( "client to close" ~= interface.fatalerror ) ) then  -- leave this event
 482                         --vdebug( "leaving this event because:", interface.nowriting or interface.fatalerror )
 483                         interface.eventwrite = false
 484                         return -1
 485                 end
 486                 if EV_TIMEOUT == event then  -- took too long to write some data to socket -> disconnect
 487                         interface.fatalerror = "timeout during writing"
 488                         debug( "writing failed:", interface.fatalerror )
 489                         interface:_close()
 490                         interface.eventwrite = false
 491                         return -1
 492                 else  -- can write :)
 493                         if interface._usingssl then  -- handle luasec
 494                                 if interface.eventreadtimeout then  -- we have to read first
 495                                         local ret = interface.readcallback( )  -- call readcallback
 496                                         --vdebug( "tried to read in writecallback, result:", ret )
 497                                 end
 498                                 if interface.eventwritetimeout then  -- luasec only
 499                                         interface.eventwritetimeout:close( )  -- first we have to close timeout event which where regged after a wantread error
 500                                         interface.eventwritetimeout = false
 501                                 end
 502                         end
 503                         interface.writebuffer = { t_concat(interface.writebuffer) }
 504                         local succ, err, byte = interface.conn:send( interface.writebuffer[1], 1, interface.writebufferlen )
 505                         --vdebug( "write data:", interface.writebuffer, "error:", err, "part:", byte )
 506                         if succ then  -- writing succesful
 507                                 interface.writebuffer[1] = nil
 508                                 interface.writebufferlen = 0
 509                                 interface:ondrain();
 510                                 if interface.fatalerror then
 511                                         debug "closing client after writing"
 512                                         interface:_close()  -- close interface if needed
 513                                 elseif interface.startsslcallback then  -- start ssl connection if needed
 514                                         debug "starting ssl handshake after writing"
 515                                         interface.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, interface.startsslcallback, 0 )
 516                                 elseif interface.eventreadtimeout then
 517                                         return EV_WRITE, EV_TIMEOUT
 518                                 end
 519                                 interface.eventwrite = nil
 520                                 return -1
 521                         elseif byte and (err == "timeout" or err == "wantwrite") then  -- want write again
 522                                 --vdebug( "writebuffer is not empty:", err )
 523                                 interface.writebuffer[1] = s_sub( interface.writebuffer[1], byte + 1, interface.writebufferlen )  -- new buffer
 524                                 interface.writebufferlen = interface.writebufferlen - byte
 525                                 if "wantread" == err then  -- happens only with luasec
 526                                         local callback = function( )
 527                                                 interface:_close()
 528                                                 interface.eventwritetimeout = nil
 529                                                 return -1;
 530                                         end
 531                                         interface.eventwritetimeout = addevent( base, nil, EV_TIMEOUT, callback, cfg.WRITE_TIMEOUT )  -- reg a new timeout event
 532                                         debug( "wantread during write attempt, reg it in readcallback but dont know what really happens next..." )
 533                                         -- hopefully this works with luasec; its simply not possible to use 2 different write events on a socket in luaevent
 534                                         return -1
 535                                 end
 536                                 return EV_WRITE, cfg.WRITE_TIMEOUT
 537                         else  -- connection was closed during writing or fatal error
 538                                 interface.fatalerror = err or "fatal error"
 539                                 debug( "connection failed in write event:", interface.fatalerror )
 540                                 interface:_close()
 541                                 interface.eventwrite = nil
 542                                 return -1
 543                         end
 544                 end
 545         end
 546
 547         interface.readcallback = function( event )  -- called on read events
 548                 --vdebug( "new client read event, id/ip/port:", tostring(interface.id), tostring(ip), tostring(port) )
 549                 if interface.noreading or interface.fatalerror then  -- leave this event
 550                         --vdebug( "leaving this event because:", tostring(interface.noreading or interface.fatalerror) )
 551                         interface.eventread = nil
 552                         return -1
 553                 end
 554                 if EV_TIMEOUT == event and interface:onreadtimeout() ~= true then
 555                         return -1 -- took too long to get some data from client -> disconnect
 556                 end
 557                 if interface._usingssl then  -- handle luasec
 558                         if interface.eventwritetimeout then  -- ok, in the past writecallback was regged
 559                                 local ret = interface.writecallback( )  -- call it
 560                                 --vdebug( "tried to write in readcallback, result:", tostring(ret) )
 561                         end
 562                         if interface.eventreadtimeout then
 563                                 interface.eventreadtimeout:close( )
 564                                 interface.eventreadtimeout = nil
 565                         end
 566                 end
 567                 local buffer, err, part = interface.conn:receive( interface._pattern )  -- receive buffer with "pattern"
 568                 --vdebug( "read data:", tostring(buffer), "error:", tostring(err), "part:", tostring(part) )
 569                 buffer = buffer or part
 570                 if buffer and #buffer > cfg.MAX_READ_LENGTH then  -- check buffer length
 571                         interface.fatalerror = "receive buffer exceeded"
 572                         debug( "fatal error:", interface.fatalerror )
 573                         interface:_close()
 574                         interface.eventread = nil
 575                         return -1
 576                 end
 577                 if err and ( err ~= "timeout" and err ~= "wantread" ) then
 578                         if "wantwrite" == err then -- need to read on write event
 579                                 if not interface.eventwrite then  -- register new write event if needed
 580                                         interface.eventwrite = addevent( base, interface.conn, EV_WRITE, interface.writecallback, cfg.WRITE_TIMEOUT )
 581                                 end
 582                                 interface.eventreadtimeout = addevent( base, nil, EV_TIMEOUT,
 583                                         function( )
 584                                                 interface:_close()
 585                                         end, cfg.READ_TIMEOUT
 586                                 )
 587                                 debug( "wantwrite during read attempt, reg it in writecallback but dont know what really happens next..." )
 588                                 -- to be honest i dont know what happens next, if it is allowed to first read, the write etc...
 589                         else  -- connection was closed or fatal error
 590                                 interface.fatalerror = err
 591                                 debug( "connection failed in read event:", interface.fatalerror )
 592                                 interface:_close()
 593                                 interface.eventread = nil
 594                                 return -1
 595                         end
 596                 else
 597                         interface.onincoming( interface, buffer, err )  -- send new data to listener
 598                 end
 599                 if interface.noreading then
 600                         interface.eventread = nil;
 601                         return -1;
 602                 end
 603                 return EV_READ, cfg.READ_TIMEOUT
 604         end
 605
 606         client:settimeout( 0 )  -- set non blocking
 607         setmetatable(interface, interface_mt)
 608         interfacelist[ interface ] = true  -- add to interfacelist
 609         return interface
 610 end
 611
 612 local function handleserver( server, addr, port, pattern, listener, sslctx )  -- creates an server interface
 613         debug "creating server interface..."
 614         local interface = {
 615                 _connections = 0;
 616
 617                 type = "server";
 618                 conn = server;
 619                 onconnect = listener.onconnect;  -- will be called when new client connected
 620                 eventread = false;  -- read event handler
 621                 eventclose = false; -- close event handler
 622                 readcallback = false; -- read event callback
 623                 fatalerror = false; -- error message
 624                 nointerface = true;  -- lock/unlock parameter
 625
 626                 _ip = addr, _port = port, _pattern = pattern,
 627                 _sslctx = sslctx;
 628         }
 629         interface.id = tostring(interface):match("%x+$");
 630         interface.readcallback = function( event )  -- server handler, called on incoming connections
 631                 --vdebug( "server can accept, id/addr/port:", interface, addr, port )
 632                 if interface.fatalerror then
 633                         --vdebug( "leaving this event because:", self.fatalerror )
 634                         interface.eventread = nil
 635                         return -1
 636                 end
 637                 local delay = cfg.ACCEPT_DELAY
 638                 if EV_TIMEOUT == event then
 639                         if interface._connections >= cfg.MAX_CONNECTIONS then  -- check connection count
 640                                 debug( "to many connections, seconds to wait for next accept:", delay )
 641                                 return EV_TIMEOUT, delay  -- timeout...
 642                         else
 643                                 return EV_READ  -- accept again
 644                         end
 645                 end
 646                 --vdebug("max connection check ok, accepting...")
 647                 local client, err = server:accept()    -- try to accept; TODO: check err
 648                 while client do
 649                         if interface._connections >= cfg.MAX_CONNECTIONS then
 650                                 client:close( )  -- refuse connection
 651                                 debug( "maximal connections reached, refuse client connection; accept delay:", delay )
 652                                 return EV_TIMEOUT, delay  -- delay for next accept attempt
 653                         end
 654                         local client_ip, client_port = client:getpeername( )
 655                         interface._connections = interface._connections + 1  -- increase connection count
 656                         local clientinterface = handleclient( client, client_ip, client_port, interface, pattern, listener, sslctx )
 657                         --vdebug( "client id:", clientinterface, "startssl:", startssl )
 658                         if has_luasec and sslctx then
 659                                 clientinterface:starttls(sslctx, true)
 660                         else
 661                                 clientinterface:_start_session( true )
 662                         end
 663                         debug( "accepted incoming client connection from:", client_ip or "<unknown IP>", client_port or "<unknown port>", "to", port or "<unknown port>");
 664
 665                         client, err = server:accept()    -- try to accept again
 666                 end
 667                 return EV_READ
 668         end
 669
 670         server:settimeout( 0 )
 671         setmetatable(interface, interface_mt)
 672         interfacelist[ interface ] = true
 673         interface:_start_session()
 674         return interface
 675 end
 676
 677 local function addserver( addr, port, listener, pattern, sslctx, startssl )  -- TODO: check arguments
 678         --vdebug( "creating new tcp server with following parameters:", addr or "nil", port or "nil", sslctx or "nil", startssl or "nil")
 679         if sslctx and not has_luasec then
 680                 debug "fatal error: luasec not found"
 681                 return nil, "luasec not found"
 682         end
 683         local server, err = socket.bind( addr, port, cfg.ACCEPT_QUEUE )  -- create server socket
 684         if not server then
 685                 debug( "creating server socket on "..addr.." port "..port.." failed:", err )
 686                 return nil, err
 687         end
 688         local interface = handleserver( server, addr, port, pattern, listener, sslctx, startssl )  -- new server handler
 689         debug( "new server created with id:", tostring(interface))
 690         return interface
 691 end
 692
 693 local function wrapclient( client, ip, port, listeners, pattern, sslctx )
 694         local interface = handleclient( client, ip, port, nil, pattern, listeners, sslctx )
 695         interface:_start_connection(sslctx)
 696         return interface, client
 697         --function handleclient( client, ip, port, server, pattern, listener, _, sslctx )  -- creates an client interface
 698 end
 699
 700 local function addclient( addr, serverport, listener, pattern, sslctx, typ )
 701         if sslctx and not has_luasec then
 702                 debug "need luasec, but not available"
 703                 return nil, "luasec not found"
 704         end
 705         if getaddrinfo and not typ then
 706                 local addrinfo, err = getaddrinfo(addr)
 707                 if not addrinfo then return nil, err end
 708                 if addrinfo[1] and addrinfo[1].family == "inet6" then
 709                         typ = "tcp6"
 710                 end
 711         end
 712         local create = socket[typ or "tcp"]
 713         if type( create ) ~= "function"  then
 714                 return nil, "invalid socket type"
 715         end
 716         local client, err = create()  -- creating new socket
 717         if not client then
 718                 debug( "cannot create socket:", err )
 719                 return nil, err
 720         end
 721         client:settimeout( 0 )  -- set nonblocking
 722         local res, err = client:connect( addr, serverport )  -- connect
 723         if res or ( err == "timeout" or err == "Operation already in progress" ) then
 724                 if client.getsockname then
 725                         addr = client:getsockname( )
 726                 end
 727                 local interface = wrapclient( client, addr, serverport, listener, pattern, sslctx )
 728                 debug( "new connection id:", interface.id )
 729                 return interface, err
 730         else
 731                 debug( "new connection failed:", err )
 732                 return nil, err
 733         end
 734 end
 735
 736 local function loop( )  -- starts the event loop
 737         base:loop( )
 738         return "quitting";
 739 end
 740
 741 local function newevent( ... )
 742         return addevent( base, ... )
 743         end
 744
 745 local function closeallservers ( arg )
 746         for item in pairs( interfacelist ) do
 747                 if item.type == "server" then
 748                         item:close( arg )
 749                 end
 750         end
 751 end
 752
 753 local function setquitting(yes)
 754         if yes then
 755                  -- Quit now
 756                  closeallservers();
 757                  base:loopexit();
 758         end
 759 end
 760
 761 local function get_backend()
 762         return base:method();
 763 end
 764
 765 -- We need to hold onto the events to stop them
 766 -- being garbage-collected
 767 local signal_events = {}; -- [signal_num] -> event object
 768 local function hook_signal(signal_num, handler)
 769         local function _handler()
 770                 local ret = handler();
 771                 if ret ~= false then -- Continue handling this signal?
 772                         return EV_SIGNAL; -- Yes
 773                 end
 774                 return -1; -- Close this event
 775         end
 776         signal_events[signal_num] = base:addevent(signal_num, EV_SIGNAL, _handler);
 777         return signal_events[signal_num];
 778 end
 779
 780 local function link(sender, receiver, buffersize)
 781         local sender_locked;
 782
 783         function receiver:ondrain()
 784                 if sender_locked then
 785                         sender:resume();
 786                         sender_locked = nil;
 787                 end
 788         end
 789
 790         function sender:onincoming(data)
 791                 receiver:write(data);
 792                 if receiver.writebufferlen >= buffersize then
 793                         sender_locked = true;
 794                         sender:pause();
 795                 end
 796         end
 797         sender:set_mode("*a");
 798 end
 799
 800 local function add_task(delay, callback)
 801         local event_handle;
 802         event_handle = base:addevent(nil, 0, function ()
 803                 local ret = callback(socket_gettime());
 804                 if ret then
 805                         return 0, ret;
 806                 elseif event_handle then
 807                         return -1;
 808                 end
 809         end
 810         , delay);
 811         return event_handle;
 812 end
 813
 814 return {
 815         cfg = cfg,
 816         base = base,
 817         loop = loop,
 818         link = link,
 819         event = levent,
 820         event_base = base,
 821         addevent = newevent,
 822         addserver = addserver,
 823         addclient = addclient,
 824         wrapclient = wrapclient,
 825         setquitting = setquitting,
 826         closeall = closeallservers,
 827         get_backend = get_backend,
 828         hook_signal = hook_signal,
 829         add_task = add_task,
 830
 831         __NAME = SCRIPT_NAME,
 832         __DATE = LAST_MODIFIED,
 833         __AUTHOR = SCRIPT_AUTHOR,
 834         __VERSION = SCRIPT_VERSION,
 835
 836 }