net/server_event.lua

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