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 can't 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                         -- don't 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          = 14 * 60,  -- 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         READ_RETRY_DELAY      = 1e-06, -- if, after reading, there is still data in buffer, wait this long and continue reading
  34         DEBUG                 = true,  -- show debug messages
  35 }
  36
  37 local pairs = pairs
  38 local select = select
  39 local require = require
  40 local tostring = tostring
  41 local setmetatable = setmetatable
  42
  43 local t_insert = table.insert
  44 local t_concat = table.concat
  45 local s_sub = string.sub
  46
  47 local coroutine_wrap = coroutine.wrap
  48 local coroutine_yield = coroutine.yield
  49
  50 local has_luasec, ssl = pcall ( require , "ssl" )
  51 local socket = require "socket"
  52 local levent = require "luaevent.core"
  53 local inet = require "util.net";
  54 local inet_pton = inet.pton;
  55
  56 local socket_gettime = socket.gettime
  57
  58 local log = require ("util.logger").init("socket")
  59
  60 local function debug(...)
  61         return log("debug", ("%s "):rep(select('#', ...)), ...)
  62 end
  63 -- local vdebug = debug;
  64
  65 local bitor = ( function( ) -- thx Rici Lake
  66         local hasbit = function( x, p )
  67                 return x % ( p + p ) >= p
  68         end
  69         return function( x, y )
  70                 local p = 1
  71                 local z = 0
  72                 local limit = x > y and x or y
  73                 while p <= limit do
  74                         if hasbit( x, p ) or hasbit( y, p ) then
  75                                 z = z + p
  76                         end
  77                         p = p + p
  78                 end
  79                 return z
  80         end
  81 end )( )
  82
  83 local base = levent.new( )
  84 local addevent = base.addevent
  85 local EV_READ = levent.EV_READ
  86 local EV_WRITE = levent.EV_WRITE
  87 local EV_TIMEOUT = levent.EV_TIMEOUT
  88 local EV_SIGNAL = levent.EV_SIGNAL
  89
  90 local EV_READWRITE = bitor( EV_READ, EV_WRITE )
  91
  92 local interfacelist = { }
  93
  94 -- Client interface methods
  95 local interface_mt = {}; interface_mt.__index = interface_mt;
  96
  97 -- Private methods
  98 function interface_mt:_close()
  99         return self:_destroy();
 100 end
 101
 102 function interface_mt:_start_connection(plainssl) -- called from wrapclient
 103         local callback = function( event )
 104                 if EV_TIMEOUT == event then  -- timeout during connection
 105                         self.fatalerror = "connection timeout"
 106                         self:ontimeout()  -- call timeout listener
 107                         self:_close()
 108                         debug( "new connection failed. id:", self.id, "error:", self.fatalerror )
 109                 else
 110                         if EV_READWRITE == event then
 111                                 if self.readcallback(event) == -1 then
 112                                         -- Fatal error occurred
 113                                         return -1;
 114                                 end
 115                         end
 116                         if plainssl and has_luasec then  -- start ssl session
 117                                 self:starttls(self._sslctx, true)
 118                         else  -- normal connection
 119                                 self:_start_session(true)
 120                         end
 121                         debug( "new connection established. id:", self.id )
 122                 end
 123                 self.eventconnect = nil
 124                 return -1
 125         end
 126         self.eventconnect = addevent( base, self.conn, EV_READWRITE, callback, cfg.CONNECT_TIMEOUT )
 127         return true
 128 end
 129 function interface_mt:_start_session(call_onconnect) -- new session, for example after startssl
 130         if self.type == "client" then
 131                 local callback = function( )
 132                         self:_lock( false,  false, false )
 133                         --vdebug( "start listening on client socket with id:", self.id )
 134                         self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
 135                         if call_onconnect then
 136                                 self:onconnect()
 137                         end
 138                         self.eventsession = nil
 139                         return -1
 140                 end
 141                 self.eventsession = addevent( base, nil, EV_TIMEOUT, callback, 0 )
 142         else
 143                 self:_lock( false )
 144                 --vdebug( "start listening on server socket with id:", self.id )
 145                 self.eventread = addevent( base, self.conn, EV_READ, self.readcallback )  -- register callback
 146         end
 147         return true
 148 end
 149 function interface_mt:_start_ssl(call_onconnect) -- old socket will be destroyed, therefore we have to close read/write events first
 150         --vdebug( "starting ssl session with client id:", self.id )
 151         local _
 152         _ = self.eventread and self.eventread:close( )  -- close events; this must be called outside of the event callbacks!
 153         _ = self.eventwrite and self.eventwrite:close( )
 154         self.eventread, self.eventwrite = nil, nil
 155         local err
 156         self.conn, err = ssl.wrap( self.conn, self._sslctx )
 157         if err then
 158                 self.fatalerror = err
 159                 self.conn = nil  -- cannot be used anymore
 160                 if call_onconnect then
 161                         self.ondisconnect = nil  -- don't call this when client isn't really connected
 162                 end
 163                 self:_close()
 164                 debug( "fatal error while ssl wrapping:", err )
 165                 return false
 166         end
 167
 168         if self.conn.sni then
 169                 if self.servername then
 170                         self.conn:sni(self.servername);
 171                 elseif self._server and type(self._server.hosts) == "table" and next(self._server.hosts) ~= nil then
 172                         self.conn:sni(self._server.hosts, true);
 173                 end
 174         end
 175
 176         self.conn:settimeout( 0 )  -- set non blocking
 177         local handshakecallback = coroutine_wrap(function( event )
 178                 local _, err
 179                 local attempt = 0
 180                 local maxattempt = cfg.MAX_HANDSHAKE_ATTEMPTS
 181                 while attempt < maxattempt do  -- no endless loop
 182                         attempt = attempt + 1
 183                         debug( "ssl handshake of client with id:"..tostring(self)..", attempt:"..attempt )
 184                         if attempt > maxattempt then
 185                                 self.fatalerror = "max handshake attempts exceeded"
 186                         elseif EV_TIMEOUT == event then
 187                                 self.fatalerror = "timeout during handshake"
 188                         else
 189                                 _, err = self.conn:dohandshake( )
 190                                 if not err then
 191                                         self:_lock( false, false, false )  -- unlock the interface; sending, closing etc allowed
 192                                         self.send = self.conn.send  -- caching table lookups with new client object
 193                                         self.receive = self.conn.receive
 194                                         if not call_onconnect then  -- trigger listener
 195                                                 self:onstatus("ssl-handshake-complete");
 196                                         end
 197                                         self:_start_session( call_onconnect )
 198                                         debug( "ssl handshake done" )
 199                                         self.eventhandshake = nil
 200                                         return -1
 201                                 end
 202                                 if err == "wantwrite" then
 203                                         event = EV_WRITE
 204                                 elseif err == "wantread" then
 205                                         event = EV_READ
 206                                 else
 207                                         debug( "ssl handshake error:", err )
 208                                         self.fatalerror = err
 209                                 end
 210                         end
 211                         if self.fatalerror then
 212                                 if call_onconnect then
 213                                         self.ondisconnect = nil  -- don't call this when client isn't really connected
 214                                 end
 215                                 self:_close()
 216                                 debug( "handshake failed because:", self.fatalerror )
 217                                 self.eventhandshake = nil
 218                                 return -1
 219                         end
 220                         event = coroutine_yield( event, cfg.HANDSHAKE_TIMEOUT )  -- yield this monster...
 221                 end
 222         end
 223         )
 224         debug "starting handshake..."
 225         self:_lock( false, true, true )  -- unlock read/write events, but keep interface locked
 226         self.eventhandshake = addevent( base, self.conn, EV_READWRITE, handshakecallback, cfg.HANDSHAKE_TIMEOUT )
 227         return true
 228 end
 229 function interface_mt:_destroy()  -- close this interface + events and call last listener
 230         debug( "closing client with id:", self.id, self.fatalerror )
 231         self:_lock( true, true, true )  -- first of all, lock the interface to avoid further actions
 232         local _
 233         _ = self.eventread and self.eventread:close( )
 234         if self.type == "client" then
 235                 _ = self.eventwrite and self.eventwrite:close( )
 236                 _ = self.eventhandshake and self.eventhandshake:close( )
 237                 _ = self.eventstarthandshake and self.eventstarthandshake:close( )
 238                 _ = self.eventconnect and self.eventconnect:close( )
 239                 _ = self.eventsession and self.eventsession:close( )
 240                 _ = self.eventwritetimeout and self.eventwritetimeout:close( )
 241                 _ = self.eventreadtimeout and self.eventreadtimeout:close( )
 242                 -- call ondisconnect listener (won't be the case if handshake failed on connect)
 243                 _ = self.ondisconnect and self:ondisconnect( self.fatalerror ~= "client to close" and self.fatalerror)
 244                 _ = self.conn and self.conn:close( ) -- close connection
 245                 _ = self._server and self._server:counter(-1);
 246                 self.eventread, self.eventwrite = nil, nil
 247                 self.eventstarthandshake, self.eventhandshake, self.eventclose = nil, nil, nil
 248                 self.readcallback, self.writecallback = nil, nil
 249         else
 250                 self.conn:close( )
 251                 self.eventread, self.eventclose = nil, nil
 252                 self.interface, self.readcallback = nil, nil
 253         end
 254         interfacelist[ self ] = nil
 255         return true
 256 end
 257
 258 function interface_mt:_lock(nointerface, noreading, nowriting)  -- lock or unlock this interface or events
 259         self.nointerface, self.noreading, self.nowriting = nointerface, noreading, nowriting
 260         return nointerface, noreading, nowriting
 261 end
 262
 263 --TODO: Deprecate
 264 function interface_mt:lock_read(switch)
 265         log("warn", ":lock_read is deprecated, use :pasue() and :resume()");
 266         if switch then
 267                 return self:pause();
 268         else
 269                 return self:resume();
 270         end
 271 end
 272
 273 function interface_mt:pause()
 274         return self:_lock(self.nointerface, true, self.nowriting);
 275 end
 276
 277 function interface_mt:resume()
 278         self:_lock(self.nointerface, false, self.nowriting);
 279         if self.readcallback and not self.eventread then
 280                 self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
 281                 return true;
 282         end
 283 end
 284
 285 function interface_mt:pause_writes()
 286         return self:_lock(self.nointerface, self.noreading, true);
 287 end
 288
 289 function interface_mt:resume_writes()
 290         self:_lock(self.nointerface, self.noreading, false);
 291         if self.writecallback and not self.eventwrite then
 292                 self.eventwrite = addevent( base, self.conn, EV_WRITE, self.writecallback, cfg.WRITE_TIMEOUT );  -- register callback
 293                 return true;
 294         end
 295 end
 296
 297
 298 function interface_mt:counter(c)
 299         if c then
 300                 self._connections = self._connections + c
 301         end
 302         return self._connections
 303 end
 304
 305 -- Public methods
 306 function interface_mt:write(data)
 307         if self.nointerface then return nil, "locked"; end
 308         --vdebug( "try to send data to client, id/data:", self.id, data )
 309         data = tostring( data )
 310         local len = #data
 311         local total = len + self.writebufferlen
 312         if total > cfg.MAX_SEND_LENGTH then  -- check buffer length
 313                 local err = "send buffer exceeded"
 314                 debug( "error:", err )  -- to much, check your app
 315                 return nil, err
 316         end
 317         t_insert(self.writebuffer, data) -- new buffer
 318         self.writebufferlen = total
 319         if not self.eventwrite and not self.nowriting  then  -- register new write event
 320                 --vdebug( "register new write event" )
 321                 self.eventwrite = addevent( base, self.conn, EV_WRITE, self.writecallback, cfg.WRITE_TIMEOUT )
 322         end
 323         return true
 324 end
 325 function interface_mt:close()
 326         if self.nointerface then return nil, "locked"; end
 327         debug( "try to close client connection with id:", self.id )
 328         if self.type == "client" then
 329                 self.fatalerror = "client to close"
 330                 if self.eventwrite then -- wait for incomplete write request
 331                         self:_lock( true, true, false )
 332                         debug "closing delayed until writebuffer is empty"
 333                         return nil, "writebuffer not empty, waiting"
 334                 else -- close now
 335                         self:_lock( true, true, true )
 336                         self:_close()
 337                         return true
 338                 end
 339         else
 340                 debug( "try to close server with id:", tostring(self.id))
 341                 self.fatalerror = "server to close"
 342                 self:_lock( true )
 343                 self:_close( 0 )
 344                 return true
 345         end
 346 end
 347
 348 function interface_mt:socket()
 349         return self.conn
 350 end
 351
 352 function interface_mt:server()
 353         return self._server or self;
 354 end
 355
 356 function interface_mt:port()
 357         return self._port
 358 end
 359
 360 function interface_mt:serverport()
 361         return self._serverport
 362 end
 363
 364 function interface_mt:ip()
 365         return self._ip
 366 end
 367
 368 function interface_mt:ssl()
 369         return self._usingssl
 370 end
 371 interface_mt.clientport = interface_mt.port -- COMPAT server_select
 372
 373 function interface_mt:type()
 374         return self._type or "client"
 375 end
 376
 377 function interface_mt:connections()
 378         return self._connections
 379 end
 380
 381 function interface_mt:address()
 382         return self.addr
 383 end
 384
 385 function interface_mt:set_sslctx(sslctx)
 386         self._sslctx = sslctx;
 387         if sslctx then
 388                 self.starttls = nil; -- use starttls() of interface_mt
 389         else
 390                 self.starttls = false; -- prevent starttls()
 391         end
 392 end
 393
 394 function interface_mt:set_mode(pattern)
 395         if pattern then
 396                 self._pattern = pattern;
 397         end
 398         return self._pattern;
 399 end
 400
 401 function interface_mt:set_send(new_send) -- luacheck: ignore 212
 402         -- No-op, we always use the underlying connection's send
 403 end
 404
 405 function interface_mt:starttls(sslctx, call_onconnect)
 406         debug( "try to start ssl at client id:", self.id )
 407         local err
 408         self._sslctx = sslctx;
 409         if self._usingssl then  -- startssl was already called
 410                 err = "ssl already active"
 411         end
 412         if err then
 413                 debug( "error:", err )
 414                 return nil, err
 415         end
 416         self._usingssl = true
 417         self.startsslcallback = function( )  -- we have to start the handshake outside of a read/write event
 418                 self.startsslcallback = nil
 419                 self:_start_ssl(call_onconnect);
 420                 self.eventstarthandshake = nil
 421                 return -1
 422         end
 423         if not self.eventwrite then
 424                 self:_lock( true, true, true )  -- lock the interface, to not disturb the handshake
 425                 self.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, self.startsslcallback, 0 )  -- add event to start handshake
 426         else
 427                 -- wait until writebuffer is empty
 428                 self:_lock( true, true, false )
 429                 debug "ssl session delayed until writebuffer is empty..."
 430         end
 431         self.starttls = false;
 432         return true
 433 end
 434
 435 function interface_mt:setoption(option, value)
 436         if self.conn.setoption then
 437                 return self.conn:setoption(option, value);
 438         end
 439         return false, "setoption not implemented";
 440 end
 441
 442 function interface_mt:setlistener(listener, data)
 443         self:ondetach(); -- Notify listener that it is no longer responsible for this connection
 444         self.onconnect = listener.onconnect;
 445         self.ondisconnect = listener.ondisconnect;
 446         self.onincoming = listener.onincoming;
 447         self.ontimeout = listener.ontimeout;
 448         self.onreadtimeout = listener.onreadtimeout;
 449         self.onstatus = listener.onstatus;
 450         self.ondetach = listener.ondetach;
 451         self.onattach = listener.onattach;
 452         self.ondrain = listener.ondrain;
 453         self:onattach(data);
 454 end
 455
 456 -- Stub handlers
 457 function interface_mt:onconnect()
 458 end
 459 function interface_mt:onincoming()
 460 end
 461 function interface_mt:ondisconnect()
 462 end
 463 function interface_mt:ontimeout()
 464 end
 465 function interface_mt:onreadtimeout()
 466         self.fatalerror = "timeout during receiving"
 467         debug( "connection failed:", self.fatalerror )
 468         self:_close()
 469         self.eventread = nil
 470 end
 471 function interface_mt:ondrain()
 472 end
 473 function interface_mt:ondetach()
 474 end
 475 function interface_mt:onattach()
 476 end
 477 function interface_mt:onstatus()
 478 end
 479
 480 -- End of client interface methods
 481
 482 local function handleclient( client, ip, port, server, pattern, listener, sslctx, extra )  -- creates an client interface
 483         --vdebug("creating client interfacce...")
 484         local interface = {
 485                 type = "client";
 486                 conn = client;
 487                 currenttime = socket_gettime( );  -- safe the origin
 488                 writebuffer = {};  -- writebuffer
 489                 writebufferlen = 0;  -- length of writebuffer
 490                 send = client.send;  -- caching table lookups
 491                 receive = client.receive;
 492                 onconnect = listener.onconnect;  -- will be called when client disconnects
 493                 ondisconnect = listener.ondisconnect;  -- will be called when client disconnects
 494                 onincoming = listener.onincoming;  -- will be called when client sends data
 495                 ontimeout = listener.ontimeout; -- called when fatal socket timeout occurs
 496                 onreadtimeout = listener.onreadtimeout; -- called when socket inactivity timeout occurs
 497                 ondrain = listener.ondrain; -- called when writebuffer is empty
 498                 ondetach = listener.ondetach; -- called when disassociating this listener from this connection
 499                 onstatus = listener.onstatus; -- called for status changes (e.g. of SSL/TLS)
 500                 eventread = false, eventwrite = false, eventclose = false,
 501                 eventhandshake = false, eventstarthandshake = false;  -- event handler
 502                 eventconnect = false, eventsession = false;  -- more event handler...
 503                 eventwritetimeout = false;  -- even more event handler...
 504                 eventreadtimeout = false;
 505                 fatalerror = false;  -- error message
 506                 writecallback = false;  -- will be called on write events
 507                 readcallback = false;  -- will be called on read events
 508                 nointerface = true;  -- lock/unlock parameter of this interface
 509                 noreading = false, nowriting = false;  -- locks of the read/writecallback
 510                 startsslcallback = false;  -- starting handshake callback
 511                 position = false;  -- position of client in interfacelist
 512
 513                 -- Properties
 514                 _ip = ip, _port = port, _server = server, _pattern = pattern,
 515                 _serverport = (server and server:port() or nil),
 516                 _sslctx = sslctx; -- parameters
 517                 _usingssl = false;  -- client is using ssl;
 518                 extra = extra;
 519                 servername = extra and extra.servername;
 520         }
 521         if not has_luasec then interface.starttls = false; end
 522         interface.id = tostring(interface):match("%x+$");
 523         interface.writecallback = function( event )  -- called on write events
 524                 --vdebug( "new client write event, id/ip/port:", interface, ip, port )
 525                 if interface.nowriting or ( interface.fatalerror and ( "client to close" ~= interface.fatalerror ) ) then  -- leave this event
 526                         --vdebug( "leaving this event because:", interface.nowriting or interface.fatalerror )
 527                         interface.eventwrite = false
 528                         return -1
 529                 end
 530                 if EV_TIMEOUT == event then  -- took too long to write some data to socket -> disconnect
 531                         interface.fatalerror = "timeout during writing"
 532                         debug( "writing failed:", interface.fatalerror )
 533                         interface:_close()
 534                         interface.eventwrite = false
 535                         return -1
 536                 else  -- can write :)
 537                         if interface._usingssl then  -- handle luasec
 538                                 if interface.eventreadtimeout then  -- we have to read first
 539                                         local ret = interface.readcallback( )  -- call readcallback
 540                                         --vdebug( "tried to read in writecallback, result:", ret )
 541                                 end
 542                                 if interface.eventwritetimeout then  -- luasec only
 543                                         interface.eventwritetimeout:close( )  -- first we have to close timeout event which where regged after a wantread error
 544                                         interface.eventwritetimeout = false
 545                                 end
 546                         end
 547                         interface.writebuffer = { t_concat(interface.writebuffer) }
 548                         local succ, err, byte = interface.conn:send( interface.writebuffer[1], 1, interface.writebufferlen )
 549                         --vdebug( "write data:", interface.writebuffer, "error:", err, "part:", byte )
 550                         if succ then  -- writing successful
 551                                 interface.writebuffer[1] = nil
 552                                 interface.writebufferlen = 0
 553                                 interface:ondrain();
 554                                 if interface.fatalerror then
 555                                         debug "closing client after writing"
 556                                         interface:_close()  -- close interface if needed
 557                                 elseif interface.startsslcallback then  -- start ssl connection if needed
 558                                         debug "starting ssl handshake after writing"
 559                                         interface.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, interface.startsslcallback, 0 )
 560                                 elseif interface.writebufferlen ~= 0 then
 561                                         -- data possibly written from ondrain
 562                                         return EV_WRITE, cfg.WRITE_TIMEOUT
 563                                 elseif interface.eventreadtimeout then
 564                                         return EV_WRITE, cfg.WRITE_TIMEOUT
 565                                 end
 566                                 interface.eventwrite = nil
 567                                 return -1
 568                         elseif byte and (err == "timeout" or err == "wantwrite") then  -- want write again
 569                                 --vdebug( "writebuffer is not empty:", err )
 570                                 interface.writebuffer[1] = s_sub( interface.writebuffer[1], byte + 1, interface.writebufferlen )  -- new buffer
 571                                 interface.writebufferlen = interface.writebufferlen - byte
 572                                 if "wantread" == err then  -- happens only with luasec
 573                                         local callback = function( )
 574                                                 interface:_close()
 575                                                 interface.eventwritetimeout = nil
 576                                                 return -1;
 577                                         end
 578                                         interface.eventwritetimeout = addevent( base, nil, EV_TIMEOUT, callback, cfg.WRITE_TIMEOUT )  -- reg a new timeout event
 579                                         debug( "wantread during write attempt, reg it in readcallback but don't know what really happens next..." )
 580                                         -- hopefully this works with luasec; its simply not possible to use 2 different write events on a socket in luaevent
 581                                         return -1
 582                                 end
 583                                 return EV_WRITE, cfg.WRITE_TIMEOUT
 584                         else  -- connection was closed during writing or fatal error
 585                                 interface.fatalerror = err or "fatal error"
 586                                 debug( "connection failed in write event:", interface.fatalerror )
 587                                 interface:_close()
 588                                 interface.eventwrite = nil
 589                                 return -1
 590                         end
 591                 end
 592         end
 593
 594         interface.readcallback = function( event )  -- called on read events
 595                 --vdebug( "new client read event, id/ip/port:", tostring(interface.id), tostring(ip), tostring(port) )
 596                 if interface.noreading or interface.fatalerror then  -- leave this event
 597                         --vdebug( "leaving this event because:", tostring(interface.noreading or interface.fatalerror) )
 598                         interface.eventread = nil
 599                         return -1
 600                 end
 601                 if EV_TIMEOUT == event and not interface.conn:dirty() and interface:onreadtimeout() ~= true then
 602                         interface.fatalerror = "timeout during receiving"
 603                         debug( "connection failed:", interface.fatalerror )
 604                         interface:_close()
 605                         interface.eventread = nil
 606                         return -1 -- took too long to get some data from client -> disconnect
 607                 end
 608                 if interface._usingssl then  -- handle luasec
 609                         if interface.eventwritetimeout then  -- ok, in the past writecallback was regged
 610                                 local ret = interface.writecallback( )  -- call it
 611                                 --vdebug( "tried to write in readcallback, result:", tostring(ret) )
 612                         end
 613                         if interface.eventreadtimeout then
 614                                 interface.eventreadtimeout:close( )
 615                                 interface.eventreadtimeout = nil
 616                         end
 617                 end
 618                 local buffer, err, part = interface.conn:receive( interface._pattern )  -- receive buffer with "pattern"
 619                 --vdebug( "read data:", tostring(buffer), "error:", tostring(err), "part:", tostring(part) )
 620                 buffer = buffer or part
 621                 if buffer and #buffer > cfg.MAX_READ_LENGTH then  -- check buffer length
 622                         interface.fatalerror = "receive buffer exceeded"
 623                         debug( "fatal error:", interface.fatalerror )
 624                         interface:_close()
 625                         interface.eventread = nil
 626                         return -1
 627                 end
 628                 if err and ( err ~= "timeout" and err ~= "wantread" ) then
 629                         if "wantwrite" == err then -- need to read on write event
 630                                 if not interface.eventwrite then  -- register new write event if needed
 631                                         interface.eventwrite = addevent( base, interface.conn, EV_WRITE, interface.writecallback, cfg.WRITE_TIMEOUT )
 632                                 end
 633                                 interface.eventreadtimeout = addevent( base, nil, EV_TIMEOUT,
 634                                         function( ) interface:_close() end, cfg.READ_TIMEOUT)
 635                                 debug( "wantwrite during read attempt, reg it in writecallback but don't know what really happens next..." )
 636                                 -- to be honest i don't know what happens next, if it is allowed to first read, the write etc...
 637                         else  -- connection was closed or fatal error
 638                                 interface.fatalerror = err
 639                                 debug( "connection failed in read event:", interface.fatalerror )
 640                                 interface:_close()
 641                                 interface.eventread = nil
 642                                 return -1
 643                         end
 644                 else
 645                         interface.onincoming( interface, buffer, err )  -- send new data to listener
 646                 end
 647                 if interface.noreading then
 648                         interface.eventread = nil;
 649                         return -1;
 650                 end
 651                 if interface.conn:dirty() then -- still data left in buffer
 652                         return EV_TIMEOUT, cfg.READ_RETRY_DELAY;
 653                 end
 654                 return EV_READ, cfg.READ_TIMEOUT
 655         end
 656
 657         client:settimeout( 0 )  -- set non blocking
 658         setmetatable(interface, interface_mt)
 659         interfacelist[ interface ] = true  -- add to interfacelist
 660         return interface
 661 end
 662
 663 local function handleserver( server, addr, port, pattern, listener, sslctx, startssl )  -- creates a server interface
 664         debug "creating server interface..."
 665         local interface = {
 666                 _connections = 0;
 667
 668                 type = "server";
 669                 conn = server;
 670                 onconnect = listener.onconnect;  -- will be called when new client connected
 671                 eventread = false;  -- read event handler
 672                 eventclose = false; -- close event handler
 673                 readcallback = false; -- read event callback
 674                 fatalerror = false; -- error message
 675                 nointerface = true;  -- lock/unlock parameter
 676
 677                 _ip = addr, _port = port, _pattern = pattern,
 678                 _sslctx = sslctx;
 679                 hosts = {};
 680         }
 681         interface.id = tostring(interface):match("%x+$");
 682         interface.readcallback = function( event )  -- server handler, called on incoming connections
 683                 --vdebug( "server can accept, id/addr/port:", interface, addr, port )
 684                 if interface.fatalerror then
 685                         --vdebug( "leaving this event because:", self.fatalerror )
 686                         interface.eventread = nil
 687                         return -1
 688                 end
 689                 local delay = cfg.ACCEPT_DELAY
 690                 if EV_TIMEOUT == event then
 691                         if interface._connections >= cfg.MAX_CONNECTIONS then  -- check connection count
 692                                 debug( "to many connections, seconds to wait for next accept:", delay )
 693                                 return EV_TIMEOUT, delay  -- timeout...
 694                         else
 695                                 return EV_READ  -- accept again
 696                         end
 697                 end
 698                 --vdebug("max connection check ok, accepting...")
 699                 local client, err = server:accept()    -- try to accept; TODO: check err
 700                 while client do
 701                         if interface._connections >= cfg.MAX_CONNECTIONS then
 702                                 client:close( )  -- refuse connection
 703                                 debug( "maximal connections reached, refuse client connection; accept delay:", delay )
 704                                 return EV_TIMEOUT, delay  -- delay for next accept attempt
 705                         end
 706                         local client_ip, client_port = client:getpeername( )
 707                         interface._connections = interface._connections + 1  -- increase connection count
 708                         local clientinterface = handleclient( client, client_ip, client_port, interface, pattern, listener, sslctx )
 709                         --vdebug( "client id:", clientinterface, "startssl:", startssl )
 710                         if has_luasec and startssl then
 711                                 clientinterface:starttls(sslctx, true)
 712                         else
 713                                 clientinterface:_start_session( true )
 714                         end
 715                         debug( "accepted incoming client connection from:", client_ip or "<unknown IP>", client_port or "<unknown port>", "to", port or "<unknown port>");
 716
 717                         client, err = server:accept()    -- try to accept again
 718                 end
 719                 return EV_READ
 720         end
 721
 722         server:settimeout( 0 )
 723         setmetatable(interface, interface_mt)
 724         interfacelist[ interface ] = true
 725         interface:_start_session()
 726         return interface
 727 end
 728
 729 local function listen(addr, port, listener, config)
 730         config = config or {}
 731         if config.sslctx and not has_luasec then
 732                 debug "fatal error: luasec not found"
 733                 return nil, "luasec not found"
 734         end
 735         local server, err = socket.bind( addr, port, cfg.ACCEPT_QUEUE )  -- create server socket
 736         if not server then
 737                 debug( "creating server socket on "..addr.." port "..port.." failed:", err )
 738                 return nil, err
 739         end
 740         local interface = handleserver( server, addr, port, config.read_size, listener, config.tls_ctx, config.tls_direct)  -- new server handler
 741         debug( "new server created with id:", tostring(interface))
 742         return interface
 743 end
 744
 745 local function addserver( addr, port, listener, pattern, sslctx )  -- TODO: check arguments
 746         --vdebug( "creating new tcp server with following parameters:", addr or "nil", port or "nil", sslctx or "nil", startssl or "nil")
 747         return listen( addr, port, listener, {
 748                 read_size = pattern,
 749                 tls_ctx = sslctx,
 750                 tls_direct = not not sslctx,
 751         });
 752 end
 753
 754 local function wrapclient( client, ip, port, listeners, pattern, sslctx, extra )
 755         local interface = handleclient( client, ip, port, nil, pattern, listeners, sslctx, extra )
 756         interface:_start_connection(sslctx)
 757         return interface, client
 758         --function handleclient( client, ip, port, server, pattern, listener, _, sslctx )  -- creates an client interface
 759 end
 760
 761 local function addclient( addr, serverport, listener, pattern, sslctx, typ, extra )
 762         if sslctx and not has_luasec then
 763                 debug "need luasec, but not available"
 764                 return nil, "luasec not found"
 765         end
 766         if not typ then
 767                 local n = inet_pton(addr);
 768                 if not n then return nil, "invalid-ip"; end
 769                 if #n == 16 then
 770                         typ = "tcp6";
 771                 elseif #n == 4 then
 772                         typ = "tcp4";
 773                 end
 774         end
 775         local create = socket[typ];
 776         if type( create ) ~= "function"  then
 777                 return nil, "invalid socket type"
 778         end
 779         local client, err = create()  -- creating new socket
 780         if not client then
 781                 debug( "cannot create socket:", err )
 782                 return nil, err
 783         end
 784         client:settimeout( 0 )  -- set nonblocking
 785         local res, err = client:setpeername( addr, serverport )  -- connect
 786         if res or ( err == "timeout" ) then
 787                 local ip, port = client:getsockname( )
 788                 local interface = wrapclient( client, ip, serverport, listener, pattern, sslctx, extra )
 789                 debug( "new connection id:", interface.id )
 790                 return interface, err
 791         else
 792                 debug( "new connection failed:", err )
 793                 return nil, err
 794         end
 795 end
 796
 797 local function loop( )  -- starts the event loop
 798         base:loop( )
 799         return "quitting";
 800 end
 801
 802 local function newevent( ... )
 803         return addevent( base, ... )
 804 end
 805
 806 local function closeallservers ( arg )
 807         for item in pairs( interfacelist ) do
 808                 if item.type == "server" then
 809                         item:close( arg )
 810                 end
 811         end
 812 end
 813
 814 local function setquitting(yes)
 815         if yes then
 816                 -- Quit now
 817                 if yes ~= "once" then
 818                         closeallservers();
 819                 end
 820                 base:loopexit();
 821         end
 822 end
 823
 824 local function get_backend()
 825         return "libevent " .. base:method();
 826 end
 827
 828 -- We need to hold onto the events to stop them
 829 -- being garbage-collected
 830 local signal_events = {}; -- [signal_num] -> event object
 831 local function hook_signal(signal_num, handler)
 832         local function _handler()
 833                 local ret = handler();
 834                 if ret ~= false then -- Continue handling this signal?
 835                         return EV_SIGNAL; -- Yes
 836                 end
 837                 return -1; -- Close this event
 838         end
 839         signal_events[signal_num] = base:addevent(signal_num, EV_SIGNAL, _handler);
 840         return signal_events[signal_num];
 841 end
 842
 843 local function link(sender, receiver, buffersize)
 844         local sender_locked;
 845
 846         function receiver:ondrain()
 847                 if sender_locked then
 848                         sender:resume();
 849                         sender_locked = nil;
 850                 end
 851         end
 852
 853         function sender:onincoming(data)
 854                 receiver:write(data);
 855                 if receiver.writebufferlen >= buffersize then
 856                         sender_locked = true;
 857                         sender:pause();
 858                 end
 859         end
 860         sender:set_mode("*a");
 861 end
 862
 863 local function add_task(delay, callback)
 864         local event_handle;
 865         event_handle = base:addevent(nil, 0, function ()
 866                 local ret = callback(socket_gettime());
 867                 if ret then
 868                         return 0, ret;
 869                 elseif event_handle then
 870                         return -1;
 871                 end
 872         end
 873         , delay);
 874         return event_handle;
 875 end
 876
 877 local function watchfd(fd, onreadable, onwriteable)
 878         local handle = {};
 879         function handle:setflags(r,w)
 880                 if r ~= nil then
 881                         if r and not self.wantread then
 882                                 self.wantread = base:addevent(fd, EV_READ, function ()
 883                                         onreadable(self);
 884                                 end);
 885                         elseif not r and self.wantread then
 886                                 self.wantread:close();
 887                                 self.wantread = nil;
 888                         end
 889                 end
 890                 if w ~= nil then
 891                         if w and not self.wantwrite then
 892                                 self.wantwrite = base:addevent(fd, EV_WRITE, function ()
 893                                         onwriteable(self);
 894                                 end);
 895                         elseif not r and self.wantread then
 896                                 self.wantwrite:close();
 897                                 self.wantwrite = nil;
 898                         end
 899                 end
 900         end
 901         handle:setflags(onreadable, onwriteable);
 902         return handle;
 903 end
 904
 905 return {
 906         cfg = cfg,
 907         base = base,
 908         loop = loop,
 909         link = link,
 910         event = levent,
 911         event_base = base,
 912         addevent = newevent,
 913         addserver = addserver,
 914         listen = listen,
 915         addclient = addclient,
 916         wrapclient = wrapclient,
 917         setquitting = setquitting,
 918         closeall = closeallservers,
 919         get_backend = get_backend,
 920         hook_signal = hook_signal,
 921         add_task = add_task,
 922         watchfd = watchfd,
 923
 924         __NAME = SCRIPT_NAME,
 925         __DATE = LAST_MODIFIED,
 926         __AUTHOR = SCRIPT_AUTHOR,
 927         __VERSION = SCRIPT_VERSION,
 928
 929 }