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
  17 local SCRIPT_NAME           = "server_event.lua"
  18 local SCRIPT_VERSION        = "0.05"
  19 local SCRIPT_AUTHOR         = "blastbeat"
  20 local LAST_MODIFIED         = "2009/11/20"
  21
  22 local cfg = {
  23         MAX_CONNECTIONS       = 100000,  -- max per server connections (use "ulimit -n" on *nix)
  24         MAX_HANDSHAKE_ATTEMPS = 10,  -- attemps to finish ssl handshake
  25         HANDSHAKE_TIMEOUT     = 1,  -- timout in seconds per handshake attemp
  26         MAX_READ_LENGTH       = 1024 * 1024 * 1024 * 1024,  -- max bytes allowed to read from sockets
  27         MAX_SEND_LENGTH       = 1024 * 1024 * 1024 * 1024,  -- max bytes size of write buffer (for writing on sockets)
  28         ACCEPT_DELAY          = 10,  -- seconds to wait until the next attemp of a full server to accept
  29         READ_TIMEOUT          = 60 * 30,  -- timeout in seconds for read data from socket
  30         WRITE_TIMEOUT         = 30,  -- timeout in seconds for write data on socket
  31         CONNECT_TIMEOUT       = 10,  -- timeout in seconds for connection attemps
  32         CLEAR_DELAY           = 5,  -- seconds to wait for clearing interface list (and calling ondisconnect listeners)
  33         DEBUG                 = true,  -- show debug messages
  34 }
  35
  36 local function use(x) return rawget(_G, x); end
  37 local print = use "print"
  38 local pcall = use "pcall"
  39 local ipairs = use "ipairs"
  40 local string = use "string"
  41 local select = use "select"
  42 local require = use "require"
  43 local tostring = use "tostring"
  44 local coroutine = use "coroutine"
  45 local setmetatable = use "setmetatable"
  46
  47 local ssl = use "ssl" or require "ssl"
  48 local socket = use "socket" or require "socket"
  49
  50 local log = require ("util.logger").init("socket")
  51
  52 local function debug(...)
  53         return log("debug", ("%s "):rep(select('#', ...)), ...)
  54 end
  55 local vdebug = debug;
  56
  57 local bitor = ( function( ) -- thx Rici Lake
  58         local hasbit = function( x, p )
  59                 return x % ( p + p ) >= p
  60         end
  61         return function( x, y )
  62                 local p = 1
  63                 local z = 0
  64                 local limit = x > y and x or y
  65                 while p <= limit do
  66                         if hasbit( x, p ) or hasbit( y, p ) then
  67                                 z = z + p
  68                         end
  69                         p = p + p
  70                 end
  71                 return z
  72         end
  73 end )( )
  74
  75 local event = require "luaevent.core"
  76 local base = event.new( )
  77 local EV_READ = event.EV_READ
  78 local EV_WRITE = event.EV_WRITE
  79 local EV_TIMEOUT = event.EV_TIMEOUT
  80
  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  -- timout 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 then  -- start ssl session
 146                                                 self:_start_ssl( self.listener.onconnect )
 147                                         else  -- normal connection
 148                                                 self:_start_session( self.listener.onconnect )
 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(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                                 self:onconnect()
 165                                 self.eventsession = nil
 166                                 return -1
 167                         end
 168                         self.eventsession = addevent( base, nil, EV_TIMEOUT, callback, 0 )
 169                 else
 170                         self:_lock( false )
 171                         --vdebug( "start listening on server socket with id:", self.id )
 172                         self.eventread = addevent( base, self.conn, EV_READ, self.readcallback )  -- register callback
 173                 end
 174                 return true
 175         end
 176         function interface_mt:_start_ssl(arg) -- old socket will be destroyed, therefore we have to close read/write events first
 177                         --vdebug( "starting ssl session with client id:", self.id )
 178                         local _
 179                         _ = self.eventread and self.eventread:close( )  -- close events; this must be called outside of the event callbacks!
 180                         _ = self.eventwrite and self.eventwrite:close( )
 181                         self.eventread, self.eventwrite = nil, nil
 182                         local err
 183                         self.conn, err = ssl.wrap( self.conn, self._sslctx )
 184                         if err then
 185                                 self.fatalerror = err
 186                                 self.conn = nil  -- cannot be used anymore
 187                                 if "onconnect" == arg then
 188                                         self.ondisconnect = nil  -- dont call this when client isnt really connected
 189                                 end
 190                                 self:_close()
 191                                 debug( "fatal error while ssl wrapping:", err )
 192                                 return false
 193                         end
 194                         self.conn:settimeout( 0 )  -- set non blocking
 195                         local handshakecallback = coroutine_wrap(
 196                                 function( event )
 197                                         local _, err
 198                                         local attempt = 0
 199                                         local maxattempt = cfg.MAX_HANDSHAKE_ATTEMPS
 200                                         while attempt < 1000 do  -- no endless loop
 201                                                 attempt = attempt + 1
 202                                                 debug( "ssl handshake of client with id:"..tostring(self).."attemp:"..attempt )
 203                                                 if attempt > maxattempt then
 204                                                         self.fatalerror = "max handshake attemps exceeded"
 205                                                 elseif EV_TIMEOUT == event then
 206                                                         self.fatalerror = "timeout during handshake"
 207                                                 else
 208                                                         _, err = self.conn:dohandshake( )
 209                                                         if not err then
 210                                                                 self:_lock( false, false, false )  -- unlock the interface; sending, closing etc allowed
 211                                                                 self.send = self.conn.send  -- caching table lookups with new client object
 212                                                                 self.receive = self.conn.receive
 213                                                                 local onsomething
 214                                                                 if "onconnect" == arg then  -- trigger listener
 215                                                                         onsomething = self.onconnect
 216                                                                 else
 217                                                                         onsomething = self.onsslconnection
 218                                                                 end
 219                                                                 self:_start_session( onsomething )
 220                                                                 debug( "ssl handshake done" )
 221                                                                 self.eventhandshake = nil
 222                                                                 return -1
 223                                                         end
 224                                                         debug( "error during ssl handshake:", err )
 225                                                         if err == "wantwrite" then
 226                                                                 event = EV_WRITE
 227                                                         elseif err == "wantread" then
 228                                                                 event = EV_READ
 229                                                         else
 230                                                                 self.fatalerror = err
 231                                                         end
 232                                                 end
 233                                                 if self.fatalerror then
 234                                                         if "onconnect" == arg 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 )  -- 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         function interface_mt:counter(c)
 285                 if c then
 286                         self._connections = self._connections + c
 287                 end
 288                 return self._connections
 289         end
 290
 291         -- Public methods
 292         function interface_mt:write(data)
 293                 if self.nowriting then return nil, "locked" end
 294                 --vdebug( "try to send data to client, id/data:", self.id, data )
 295                 data = tostring( data )
 296                 local len = string_len( data )
 297                 local total = len + self.writebufferlen
 298                 if total > cfg.MAX_SEND_LENGTH then  -- check buffer length
 299                         local err = "send buffer exceeded"
 300                         debug( "error:", err )  -- to much, check your app
 301                         return nil, err
 302                 end
 303                 self.writebuffer = self.writebuffer .. data -- new buffer
 304                 self.writebufferlen = total
 305                 if not self.eventwrite then  -- register new write event
 306                         --vdebug( "register new write event" )
 307                         self.eventwrite = addevent( base, self.conn, EV_WRITE, self.writecallback, cfg.WRITE_TIMEOUT )
 308                 end
 309                 return true
 310         end
 311         function interface_mt:close(now)
 312                 if self.nointerface then return nil, "locked"; end
 313                 debug( "try to close client connection with id:", self.id )
 314                 if self.type == "client" then
 315                         self.fatalerror = "client to close"
 316                         if ( not self.eventwrite ) or now then  -- try to close immediately
 317                                 self:_lock( true, true, true )
 318                                 self:_close()
 319                                 return true
 320                         else  -- wait for incomplete write request
 321                                 self:_lock( true, true, false )
 322                                 debug "closing delayed until writebuffer is empty"
 323                                 return nil, "writebuffer not empty, waiting"
 324                         end
 325                 else
 326                         debug( "try to close server with id:", self.id, "args:", now )
 327                         self.fatalerror = "server to close"
 328                         self:_lock( true )
 329                         local count = 0
 330                         for _, item in ipairs( interfacelist( ) ) do
 331                                 if ( item.type ~= "server" ) and ( item._server == self ) then  -- client/server match
 332                                         if item:close( now ) then  -- writebuffer was empty
 333                                                 count = count + 1
 334                                         end
 335                                 end
 336                         end
 337                         local timeout = 0  -- dont wait for unfinished writebuffers of clients...
 338                         if not now then
 339                                 timeout = cfg.WRITE_TIMEOUT  -- ...or wait for it
 340                         end
 341                         self:_close( timeout )  -- add new event to remove the server interface
 342                         debug( "seconds remained until server is closed:", timeout )
 343                         return count  -- returns finished clients with empty writebuffer
 344                 end
 345         end
 346
 347         function interface_mt:server()
 348                 return self._server or self;
 349         end
 350
 351         function interface_mt:port()
 352                 return self._port
 353         end
 354
 355         function interface_mt:serverport()
 356                 return self._serverport
 357         end
 358
 359         function interface_mt:ip()
 360                 return self._ip
 361         end
 362
 363         function interface_mt:ssl()
 364                 return self._usingssl
 365         end
 366
 367         function interface_mt:type()
 368                 return self._type or "client"
 369         end
 370
 371         function interface_mt:connections()
 372                 return self._connections
 373         end
 374
 375         function interface_mt:address()
 376                 return self.addr
 377         end
 378
 379         function interface_mt:set_sslctx(sslctx)
 380                 self._sslctx = sslctx;
 381                 if sslctx then
 382                         self.starttls = nil; -- use starttls() of interface_mt
 383                 else
 384                         self.starttls = false; -- prevent starttls()
 385                 end
 386         end
 387
 388         function interface_mt:set_send(new_send)
 389                 -- No-op, we always use the underlying connection's send
 390         end
 391
 392         function interface_mt:starttls()
 393                 debug( "try to start ssl at client id:", self.id )
 394                 local err
 395                 if not self._sslctx then  -- no ssl available
 396                         err = "no ssl context available"
 397                 elseif self._usingssl then  -- startssl was already called
 398                         err = "ssl already active"
 399                 end
 400                 if err then
 401                         debug( "error:", err )
 402                         return nil, err
 403                 end
 404                 self._usingssl = true
 405                 self.startsslcallback = function( )  -- we have to start the handshake outside of a read/write event
 406                         self.startsslcallback = nil
 407                         self:_start_ssl();
 408                         self.eventstarthandshake = nil
 409                         return -1
 410                 end
 411                 if not self.eventwrite then
 412                         self:_lock( true, true, true )  -- lock the interface, to not disturb the handshake
 413                         self.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, self.startsslcallback, 0 )  -- add event to start handshake
 414                 else  -- wait until writebuffer is empty
 415                         self:_lock( true, true, false )
 416                         debug "ssl session delayed until writebuffer is empty..."
 417                 end
 418                 return true
 419         end
 420
 421         -- Stub handlers
 422         function interface_mt:onconnect()
 423         end
 424         function interface_mt:onincoming()
 425         end
 426         function interface_mt:ondisconnect()
 427         end
 428         function interface_mt:ontimeout()
 429         end
 430 end
 431
 432 -- End of client interface methods
 433
 434 local handleclient;
 435 do
 436         local string_sub = string.sub  -- caching table lookups
 437         local string_len = string.len
 438         local addevent = base.addevent
 439         local coroutine_wrap = coroutine.wrap
 440         local socket_gettime = socket.gettime
 441         local coroutine_yield = coroutine.yield
 442         function handleclient( client, ip, port, server, pattern, listener, _, sslctx )  -- creates an client interface
 443                 --vdebug("creating client interfacce...")
 444                 local interface = {
 445                         type = "client";
 446                         conn = client;
 447                         currenttime = socket_gettime( );  -- safe the origin
 448                         writebuffer = "";  -- writebuffer
 449                         writebufferlen = 0;  -- length of writebuffer
 450                         send = client.send;  -- caching table lookups
 451                         receive = client.receive;
 452                         onconnect = listener.onconnect;  -- will be called when client disconnects
 453                         ondisconnect = listener.ondisconnect;  -- will be called when client disconnects
 454                         onincoming = listener.onincoming;  -- will be called when client sends data
 455                         ontimeout = listener.ontimeout; -- called when fatal socket timeout occurs
 456                         eventread = false, eventwrite = false, eventclose = false,
 457                         eventhandshake = false, eventstarthandshake = false;  -- event handler
 458                         eventconnect = false, eventsession = false;  -- more event handler...
 459                         eventwritetimeout = false;  -- even more event handler...
 460                         eventreadtimeout = false;
 461                         fatalerror = false;  -- error message
 462                         writecallback = false;  -- will be called on write events
 463                         readcallback = false;  -- will be called on read events
 464                         nointerface = true;  -- lock/unlock parameter of this interface
 465                         noreading = false, nowriting = false;  -- locks of the read/writecallback
 466                         startsslcallback = false;  -- starting handshake callback
 467                         position = false;  -- position of client in interfacelist
 468
 469                         -- Properties
 470                         _ip = ip, _port = port, _server = server, _pattern = pattern,
 471                         _serverport = (server and server:port() or nil),
 472                         _sslctx = sslctx; -- parameters
 473                         _usingssl = false;  -- client is using ssl;
 474                 }
 475                 if not sslctx then
 476                         interface.starttls = false -- don't allow TLS
 477                 end
 478                 interface.id = tostring(interface):match("%x+$");
 479                 interface.writecallback = function( event )  -- called on write events
 480                         --vdebug( "new client write event, id/ip/port:", interface, ip, port )
 481                         if interface.nowriting or ( interface.fatalerror and ( "client to close" ~= interface.fatalerror ) ) then  -- leave this event
 482                                 --vdebug( "leaving this event because:", interface.nowriting or interface.fatalerror )
 483                                 interface.eventwrite = false
 484                                 return -1
 485                         end
 486                         if EV_TIMEOUT == event then  -- took too long to write some data to socket -> disconnect
 487                                 interface.fatalerror = "timeout during writing"
 488                                 debug( "writing failed:", interface.fatalerror )
 489                                 interface:_close()
 490                                 interface.eventwrite = false
 491                                 return -1
 492                         else  -- can write :)
 493                                 if interface._usingssl then  -- handle luasec
 494                                         if interface.eventreadtimeout then  -- we have to read first
 495                                                 local ret = interface.readcallback( )  -- call readcallback
 496                                                 --vdebug( "tried to read in writecallback, result:", ret )
 497                                         end
 498                                         if interface.eventwritetimeout then  -- luasec only
 499                                                 interface.eventwritetimeout:close( )  -- first we have to close timeout event which where regged after a wantread error
 500                                                 interface.eventwritetimeout = false
 501                                         end
 502                                 end
 503                                 local succ, err, byte = interface.conn:send( interface.writebuffer, 1, interface.writebufferlen )
 504                                 --vdebug( "write data:", interface.writebuffer, "error:", err, "part:", byte )
 505                                 if succ then  -- writing succesful
 506                                         interface.writebuffer = ""
 507                                         interface.writebufferlen = 0
 508                                         if interface.fatalerror then
 509                                                 debug "closing client after writing"
 510                                                 interface:_close()  -- close interface if needed
 511                                         elseif interface.startsslcallback then  -- start ssl connection if needed
 512                                                 debug "starting ssl handshake after writing"
 513                                                 interface.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, interface.startsslcallback, 0 )
 514                                         elseif interface.eventreadtimeout then
 515                                                 return EV_WRITE, EV_TIMEOUT
 516                                         end
 517                                         interface.eventwrite = nil
 518                                         return -1
 519                                 elseif byte then  -- want write again
 520                                         --vdebug( "writebuffer is not empty:", err )
 521                                         interface.writebuffer = string_sub( interface.writebuffer, byte + 1, interface.writebufferlen )  -- new buffer
 522                                         interface.writebufferlen = interface.writebufferlen - byte
 523                                         if "wantread" == err then  -- happens only with luasec
 524                                                 local callback = function( )
 525                                                         interface:_close()
 526                                                         interface.eventwritetimeout = nil
 527                                                         return evreturn, evtimeout
 528                                                 end
 529                                                 interface.eventwritetimeout = addevent( base, nil, EV_TIMEOUT, callback, cfg.WRITE_TIMEOUT )  -- reg a new timeout event
 530                                                 debug( "wantread during write attemp, reg it in readcallback but dont know what really happens next..." )
 531                                                 -- hopefully this works with luasec; its simply not possible to use 2 different write events on a socket in luaevent
 532                                                 return -1
 533                                         end
 534                                         return EV_WRITE, cfg.WRITE_TIMEOUT
 535                                 else  -- connection was closed during writing or fatal error
 536                                         interface.fatalerror = err or "fatal error"
 537                                         debug( "connection failed in write event:", interface.fatalerror )
 538                                         interface:_close()
 539                                         interface.eventwrite = nil
 540                                         return -1
 541                                 end
 542                         end
 543                 end
 544
 545                 interface.readcallback = function( event )  -- called on read events
 546                         --vdebug( "new client read event, id/ip/port:", tostring(interface.id), tostring(ip), tostring(port) )
 547                         if interface.noreading or interface.fatalerror then  -- leave this event
 548                                 --vdebug( "leaving this event because:", tostring(interface.noreading or interface.fatalerror) )
 549                                 interface.eventread = nil
 550                                 return -1
 551                         end
 552                         if EV_TIMEOUT == event then  -- took too long to get some data from client -> disconnect
 553                                 interface.fatalerror = "timeout during receiving"
 554                                 debug( "connection failed:", interface.fatalerror )
 555                                 interface:_close()
 556                                 interface.eventread = nil
 557                                 return -1
 558                         else -- can read
 559                                 if interface._usingssl then  -- handle luasec
 560                                         if interface.eventwritetimeout then  -- ok, in the past writecallback was regged
 561                                                 local ret = interface.writecallback( )  -- call it
 562                                                 --vdebug( "tried to write in readcallback, result:", tostring(ret) )
 563                                         end
 564                                         if interface.eventreadtimeout then
 565                                                 interface.eventreadtimeout:close( )
 566                                                 interface.eventreadtimeout = nil
 567                                         end
 568                                 end
 569                                 local buffer, err, part = interface.conn:receive( pattern )  -- receive buffer with "pattern"
 570                                 --vdebug( "read data:", tostring(buffer), "error:", tostring(err), "part:", tostring(part) )
 571                                 buffer = buffer or part or ""
 572                                 local len = string_len( buffer )
 573                                 if len > cfg.MAX_READ_LENGTH then  -- check buffer length
 574                                         interface.fatalerror = "receive buffer exceeded"
 575                                         debug( "fatal error:", interface.fatalerror )
 576                                         interface:_close()
 577                                         interface.eventread = nil
 578                                         return -1
 579                                 end
 580                                 interface.onincoming( interface, buffer, err )  -- send new data to listener
 581                                 if err and ( err ~= "timeout" and err ~= "wantread" ) then
 582                                         if "wantwrite" == err then -- need to read on write event
 583                                                 if not interface.eventwrite then  -- register new write event if needed
 584                                                         interface.eventwrite = addevent( base, interface.conn, EV_WRITE, interface.writecallback, cfg.WRITE_TIMEOUT )
 585                                                 end
 586                                                 interface.eventreadtimeout = addevent( base, nil, EV_TIMEOUT,
 587                                                         function( )
 588                                                                 interface:_close()
 589                                                         end, cfg.READ_TIMEOUT
 590                                                 )
 591                                                 debug( "wantwrite during read attemp, reg it in writecallback but dont know what really happens next..." )
 592                                                 -- to be honest i dont know what happens next, if it is allowed to first read, the write etc...
 593                                         else  -- connection was closed or fatal error
 594                                                 interface.fatalerror = err
 595                                                 debug( "connection failed in read event:", interface.fatalerror )
 596                                                 interface:_close()
 597                                                 interface.eventread = nil
 598                                                 return -1
 599                                         end
 600                                 end
 601                                 return EV_READ, cfg.READ_TIMEOUT
 602                         end
 603                 end
 604
 605                 client:settimeout( 0 )  -- set non blocking
 606                 setmetatable(interface, interface_mt)
 607                 interfacelist( "add", interface )  -- add to interfacelist
 608                 return interface
 609         end
 610 end
 611
 612 local handleserver
 613 do
 614         function handleserver( server, addr, port, pattern, listener, sslctx, startssl )  -- creates an server interface
 615                 debug "creating server interface..."
 616                 local interface = {
 617                         _connections = 0;
 618
 619                         conn = server;
 620                         onconnect = listener.onconnect;  -- will be called when new client connected
 621                         eventread = false;  -- read event handler
 622                         eventclose = false; -- close event handler
 623                         readcallback = false; -- read event callback
 624                         fatalerror = false; -- error message
 625                         nointerface = true;  -- lock/unlock parameter
 626                 }
 627                 interface.id = tostring(interface):match("%x+$");
 628                 interface.readcallback = function( event )  -- server handler, called on incoming connections
 629                         --vdebug( "server can accept, id/addr/port:", interface, addr, port )
 630                         if interface.fatalerror then
 631                                 --vdebug( "leaving this event because:", self.fatalerror )
 632                                 interface.eventread = nil
 633                                 return -1
 634                         end
 635                         local delay = cfg.ACCEPT_DELAY
 636                         if EV_TIMEOUT == event then
 637                                 if interface._connections >= cfg.MAX_CONNECTIONS then  -- check connection count
 638                                         debug( "to many connections, seconds to wait for next accept:", delay )
 639                                         return EV_TIMEOUT, delay  -- timeout...
 640                                 else
 641                                         return EV_READ  -- accept again
 642                                 end
 643                         end
 644                         --vdebug("max connection check ok, accepting...")
 645                         local client, err = server:accept()    -- try to accept; TODO: check err
 646                         while client do
 647                                 if interface._connections >= cfg.MAX_CONNECTIONS then
 648                                         client:close( )  -- refuse connection
 649                                         debug( "maximal connections reached, refuse client connection; accept delay:", delay )
 650                                         return EV_TIMEOUT, delay  -- delay for next accept attemp
 651                                 end
 652                                 local ip, port = client:getpeername( )
 653                                 interface._connections = interface._connections + 1  -- increase connection count
 654                                 local clientinterface = handleclient( client, ip, port, interface, pattern, listener, nil, sslctx )
 655                                 --vdebug( "client id:", clientinterface, "startssl:", startssl )
 656                                 if startssl then
 657                                         clientinterface:_start_ssl( clientinterface.onconnect )
 658                                 else
 659                                         clientinterface:_start_session( clientinterface.onconnect )
 660                                 end
 661                                 debug( "accepted incoming client connection from:", ip, port )
 662                                 client, err = server:accept()    -- try to accept again
 663                         end
 664                         return EV_READ
 665                 end
 666
 667                 server:settimeout( 0 )
 668                 setmetatable(interface, interface_mt)
 669                 interfacelist( "add", interface )
 670                 interface:_start_session()
 671                 return interface
 672         end
 673 end
 674
 675 local addserver = ( function( )
 676         return function( addr, port, listener, pattern, sslcfg, startssl )  -- TODO: check arguments
 677                 --vdebug( "creating new tcp server with following parameters:", addr or "nil", port or "nil", sslcfg or "nil", startssl or "nil")
 678                 local server, err = socket.bind( addr, port, cfg.ACCEPT_QUEUE )  -- create server socket
 679                 if not server then
 680                         debug( "creating server socket failed because:", err )
 681                         return nil, err
 682                 end
 683                 local sslctx
 684                 if sslcfg then
 685                         if not ssl then
 686                                 debug "fatal error: luasec not found"
 687                                 return nil, "luasec not found"
 688                         end
 689                         sslctx, err = ssl.newcontext( sslcfg )
 690                         if err then
 691                                 debug( "error while creating new ssl context for server socket:", err )
 692                                 return nil, err
 693                         end
 694                 end
 695                 local interface = handleserver( server, addr, port, pattern, listener, sslctx, startssl )  -- new server handler
 696                 debug( "new server created with id:", tostring(interface))
 697                 return interface
 698         end
 699 end )( )
 700
 701 local addclient, wrapclient
 702 do
 703         function wrapclient( client, ip, port, listeners, pattern, sslctx, startssl )
 704                 local interface = handleclient( client, ip, port, nil, pattern, listeners, sslctx )
 705                 interface:_start_session()
 706                 return interface
 707                 --function handleclient( client, ip, port, server, pattern, listener, _, sslctx )  -- creates an client interface
 708         end
 709
 710         function addclient( addr, serverport, listener, pattern, localaddr, localport, sslcfg, startssl )
 711                 local client, err = socket.tcp()  -- creating new socket
 712                 if not client then
 713                         debug( "cannot create socket:", err )
 714                         return nil, err
 715                 end
 716                 client:settimeout( 0 )  -- set nonblocking
 717                 if localaddr then
 718                         local res, err = client:bind( localaddr, localport, -1 )
 719                         if not res then
 720                                 debug( "cannot bind client:", err )
 721                                 return nil, err
 722                         end
 723                 end
 724                 local sslctx
 725                 if sslcfg then  -- handle ssl/new context
 726                         if not ssl then
 727                                 debug "need luasec, but not available"
 728                                 return nil, "luasec not found"
 729                         end
 730                         sslctx, err = ssl.newcontext( sslcfg )
 731                         if err then
 732                                 debug( "cannot create new ssl context:", err )
 733                                 return nil, err
 734                         end
 735                 end
 736                 local res, err = client:connect( addr, serverport )  -- connect
 737                 if res or ( err == "timeout" ) then
 738                         local ip, port = client:getsockname( )
 739                         local server = function( )
 740                                 return nil, "this is a dummy server interface"
 741                         end
 742                         local interface = wrapclient( client, ip, serverport, listeners, pattern, sslctx, startssl )
 743                         interface:_start_connection( startssl )
 744                         debug( "new connection id:", interface.id )
 745                         return interface, err
 746                 else
 747                         debug( "new connection failed:", err )
 748                         return nil, err
 749                 end
 750         end
 751 end
 752
 753
 754 local loop = function( )  -- starts the event loop
 755         base:loop( )
 756         return "quitting";
 757 end
 758
 759 local newevent = ( function( )
 760         local add = base.addevent
 761         return function( ... )
 762                 return add( base, ... )
 763         end
 764 end )( )
 765
 766 local closeallservers = function( arg )
 767         for _, item in ipairs( interfacelist( ) ) do
 768                 if item.type == "server" then
 769                         item:close( arg )
 770                 end
 771         end
 772 end
 773
 774 local function setquitting(yes)
 775         if yes then
 776                  -- Quit now
 777                  closeallservers();
 778                  base:loopexit();
 779         end
 780 end
 781
 782 function get_backend()
 783         return base:method();
 784 end
 785
 786 return {
 787
 788         cfg = cfg,
 789         base = base,
 790         loop = loop,
 791         event = event,
 792         event_base = base,
 793         addevent = newevent,
 794         addserver = addserver,
 795         addclient = addclient,
 796         wrapclient = wrapclient,
 797         setquitting = setquitting,
 798         closeall = closeallservers,
 799         get_backend = get_backend,
 800
 801         __NAME = SCRIPT_NAME,
 802         __DATE = LAST_MODIFIED,
 803         __AUTHOR = SCRIPT_AUTHOR,
 804         __VERSION = SCRIPT_VERSION,
 805
 806 }