net/server_select.lua

   1 --
   2 -- server.lua by blastbeat of the luadch project
   3 -- Re-used here under the MIT/X Consortium License
   4 --
   5 -- Modifications (C) 2008-2010 Matthew Wild, Waqas Hussain
   6 --
   7
   8 -- // wrapping luadch stuff // --
   9
  10 local use = function( what )
  11         return _G[ what ]
  12 end
  13
  14 local log, table_concat = require ("util.logger").init("socket"), table.concat;
  15 local out_put = function (...) return log("debug", table_concat{...}); end
  16 local out_error = function (...) return log("warn", table_concat{...}); end
  17
  18 ----------------------------------// DECLARATION //--
  19
  20 --// constants //--
  21
  22 local STAT_UNIT = 1 -- byte
  23
  24 --// lua functions //--
  25
  26 local type = use "type"
  27 local pairs = use "pairs"
  28 local ipairs = use "ipairs"
  29 local tonumber = use "tonumber"
  30 local tostring = use "tostring"
  31
  32 --// lua libs //--
  33
  34 local os = use "os"
  35 local table = use "table"
  36 local string = use "string"
  37 local coroutine = use "coroutine"
  38
  39 --// lua lib methods //--
  40
  41 local os_difftime = os.difftime
  42 local math_min = math.min
  43 local math_huge = math.huge
  44 local table_concat = table.concat
  45 local string_sub = string.sub
  46 local coroutine_wrap = coroutine.wrap
  47 local coroutine_yield = coroutine.yield
  48
  49 --// extern libs //--
  50
  51 local luasec = use "ssl"
  52 local luasocket = use "socket" or require "socket"
  53 local luasocket_gettime = luasocket.gettime
  54
  55 --// extern lib methods //--
  56
  57 local ssl_wrap = ( luasec and luasec.wrap )
  58 local socket_bind = luasocket.bind
  59 local socket_sleep = luasocket.sleep
  60 local socket_select = luasocket.select
  61
  62 --// functions //--
  63
  64 local id
  65 local loop
  66 local stats
  67 local idfalse
  68 local closeall
  69 local addsocket
  70 local addserver
  71 local addtimer
  72 local getserver
  73 local wrapserver
  74 local getsettings
  75 local closesocket
  76 local removesocket
  77 local removeserver
  78 local wrapconnection
  79 local changesettings
  80
  81 --// tables //--
  82
  83 local _server
  84 local _readlist
  85 local _timerlist
  86 local _sendlist
  87 local _socketlist
  88 local _closelist
  89 local _readtimes
  90 local _writetimes
  91
  92 --// simple data types //--
  93
  94 local _
  95 local _readlistlen
  96 local _sendlistlen
  97 local _timerlistlen
  98
  99 local _sendtraffic
 100 local _readtraffic
 101
 102 local _selecttimeout
 103 local _sleeptime
 104 local _tcpbacklog
 105
 106 local _starttime
 107 local _currenttime
 108
 109 local _maxsendlen
 110 local _maxreadlen
 111
 112 local _checkinterval
 113 local _sendtimeout
 114 local _readtimeout
 115
 116 local _timer
 117
 118 local _maxselectlen
 119 local _maxfd
 120
 121 local _maxsslhandshake
 122
 123 ----------------------------------// DEFINITION //--
 124
 125 _server = { } -- key = port, value = table; list of listening servers
 126 _readlist = { } -- array with sockets to read from
 127 _sendlist = { } -- arrary with sockets to write to
 128 _timerlist = { } -- array of timer functions
 129 _socketlist = { } -- key = socket, value = wrapped socket (handlers)
 130 _readtimes = { } -- key = handler, value = timestamp of last data reading
 131 _writetimes = { } -- key = handler, value = timestamp of last data writing/sending
 132 _closelist = { } -- handlers to close
 133
 134 _readlistlen = 0 -- length of readlist
 135 _sendlistlen = 0 -- length of sendlist
 136 _timerlistlen = 0 -- lenght of timerlist
 137
 138 _sendtraffic = 0 -- some stats
 139 _readtraffic = 0
 140
 141 _selecttimeout = 1 -- timeout of socket.select
 142 _sleeptime = 0 -- time to wait at the end of every loop
 143 _tcpbacklog = 128 -- some kind of hint to the OS
 144
 145 _maxsendlen = 51000 * 1024 -- max len of send buffer
 146 _maxreadlen = 25000 * 1024 -- max len of read buffer
 147
 148 _checkinterval = 30 -- interval in secs to check idle clients
 149 _sendtimeout = 60000 -- allowed send idle time in secs
 150 _readtimeout = 6 * 60 * 60 -- allowed read idle time in secs
 151
 152 local is_windows = package.config:sub(1,1) == "\\" -- check the directory separator, to detemine whether this is Windows
 153 _maxfd = (is_windows and math.huge) or luasocket._SETSIZE or 1024 -- max fd number, limit to 1024 by default to prevent glibc buffer overflow, but not on Windows
 154 _maxselectlen = luasocket._SETSIZE or 1024 -- But this still applies on Windows
 155
 156 _maxsslhandshake = 30 -- max handshake round-trips
 157
 158 ----------------------------------// PRIVATE //--
 159
 160 wrapserver = function( listeners, socket, ip, serverport, pattern, sslctx ) -- this function wraps a server -- FIXME Make sure FD < _maxfd
 161
 162         if socket:getfd() >= _maxfd then
 163                 out_error("server.lua: Disallowed FD number: "..socket:getfd())
 164                 socket:close()
 165                 return nil, "fd-too-large"
 166         end
 167
 168         local connections = 0
 169
 170         local dispatch, disconnect = listeners.onconnect, listeners.ondisconnect
 171
 172         local accept = socket.accept
 173
 174         --// public methods of the object //--
 175
 176         local handler = { }
 177
 178         handler.shutdown = function( ) end
 179
 180         handler.ssl = function( )
 181                 return sslctx ~= nil
 182         end
 183         handler.sslctx = function( )
 184                 return sslctx
 185         end
 186         handler.remove = function( )
 187                 connections = connections - 1
 188                 if handler then
 189                         handler.resume( )
 190                 end
 191         end
 192         handler.close = function()
 193                 socket:close( )
 194                 _sendlistlen = removesocket( _sendlist, socket, _sendlistlen )
 195                 _readlistlen = removesocket( _readlist, socket, _readlistlen )
 196                 _server[ip..":"..serverport] = nil;
 197                 _socketlist[ socket ] = nil
 198                 handler = nil
 199                 socket = nil
 200                 --mem_free( )
 201                 out_put "server.lua: closed server handler and removed sockets from list"
 202         end
 203         handler.pause = function( hard )
 204                 if not handler.paused then
 205                         _readlistlen = removesocket( _readlist, socket, _readlistlen )
 206                         if hard then
 207                                 _socketlist[ socket ] = nil
 208                                 socket:close( )
 209                                 socket = nil;
 210                         end
 211                         handler.paused = true;
 212                 end
 213         end
 214         handler.resume = function( )
 215                 if handler.paused then
 216                         if not socket then
 217                                 socket = socket_bind( ip, serverport, _tcpbacklog );
 218                                 socket:settimeout( 0 )
 219                         end
 220                         _readlistlen = addsocket(_readlist, socket, _readlistlen)
 221                         _socketlist[ socket ] = handler
 222                         handler.paused = false;
 223                 end
 224         end
 225         handler.ip = function( )
 226                 return ip
 227         end
 228         handler.serverport = function( )
 229                 return serverport
 230         end
 231         handler.socket = function( )
 232                 return socket
 233         end
 234         handler.readbuffer = function( )
 235                 if _readlistlen >= _maxselectlen or _sendlistlen >= _maxselectlen then
 236                         handler.pause( )
 237                         out_put( "server.lua: refused new client connection: server full" )
 238                         return false
 239                 end
 240                 local client, err = accept( socket )    -- try to accept
 241                 if client then
 242                         local ip, clientport = client:getpeername( )
 243                         local handler, client, err = wrapconnection( handler, listeners, client, ip, serverport, clientport, pattern, sslctx ) -- wrap new client socket
 244                         if err then -- error while wrapping ssl socket
 245                                 return false
 246                         end
 247                         connections = connections + 1
 248                         out_put( "server.lua: accepted new client connection from ", tostring(ip), ":", tostring(clientport), " to ", tostring(serverport))
 249                         if dispatch and not sslctx then -- SSL connections will notify onconnect when handshake completes
 250                                 return dispatch( handler );
 251                         end
 252                         return;
 253                 elseif err then -- maybe timeout or something else
 254                         out_put( "server.lua: error with new client connection: ", tostring(err) )
 255                         return false
 256                 end
 257         end
 258         return handler
 259 end
 260
 261 wrapconnection = function( server, listeners, socket, ip, serverport, clientport, pattern, sslctx ) -- this function wraps a client to a handler object
 262
 263         if socket:getfd() >= _maxfd then
 264                 out_error("server.lua: Disallowed FD number: "..socket:getfd()) -- PROTIP: Switch to libevent
 265                 socket:close( ) -- Should we send some kind of error here?
 266                 if server then
 267                         server.pause( )
 268                 end
 269                 return nil, nil, "fd-too-large"
 270         end
 271         socket:settimeout( 0 )
 272
 273         --// local import of socket methods //--
 274
 275         local send
 276         local receive
 277         local shutdown
 278
 279         --// private closures of the object //--
 280
 281         local ssl
 282
 283         local dispatch = listeners.onincoming
 284         local status = listeners.onstatus
 285         local disconnect = listeners.ondisconnect
 286         local drain = listeners.ondrain
 287         local onreadtimeout = listeners.onreadtimeout;
 288
 289         local bufferqueue = { } -- buffer array
 290         local bufferqueuelen = 0        -- end of buffer array
 291
 292         local toclose
 293         local fatalerror
 294         local needtls
 295
 296         local bufferlen = 0
 297
 298         local noread = false
 299         local nosend = false
 300
 301         local sendtraffic, readtraffic = 0, 0
 302
 303         local maxsendlen = _maxsendlen
 304         local maxreadlen = _maxreadlen
 305
 306         --// public methods of the object //--
 307
 308         local handler = bufferqueue -- saves a table ^_^
 309
 310         handler.dispatch = function( )
 311                 return dispatch
 312         end
 313         handler.disconnect = function( )
 314                 return disconnect
 315         end
 316         handler.onreadtimeout = onreadtimeout;
 317
 318         handler.setlistener = function( self, listeners )
 319                 dispatch = listeners.onincoming
 320                 disconnect = listeners.ondisconnect
 321                 status = listeners.onstatus
 322                 drain = listeners.ondrain
 323                 handler.onreadtimeout = listeners.onreadtimeout
 324         end
 325         handler.getstats = function( )
 326                 return readtraffic, sendtraffic
 327         end
 328         handler.ssl = function( )
 329                 return ssl
 330         end
 331         handler.sslctx = function ( )
 332                 return sslctx
 333         end
 334         handler.send = function( _, data, i, j )
 335                 return send( socket, data, i, j )
 336         end
 337         handler.receive = function( pattern, prefix )
 338                 return receive( socket, pattern, prefix )
 339         end
 340         handler.shutdown = function( pattern )
 341                 return shutdown( socket, pattern )
 342         end
 343         handler.setoption = function (self, option, value)
 344                 if socket.setoption then
 345                         return socket:setoption(option, value);
 346                 end
 347                 return false, "setoption not implemented";
 348         end
 349         handler.force_close = function ( self, err )
 350                 if bufferqueuelen ~= 0 then
 351                         out_put("server.lua: discarding unwritten data for ", tostring(ip), ":", tostring(clientport))
 352                         bufferqueuelen = 0;
 353                 end
 354                 return self:close(err);
 355         end
 356         handler.close = function( self, err )
 357                 if not handler then return true; end
 358                 _readlistlen = removesocket( _readlist, socket, _readlistlen )
 359                 _readtimes[ handler ] = nil
 360                 if bufferqueuelen ~= 0 then
 361                         handler.sendbuffer() -- Try now to send any outstanding data
 362                         if bufferqueuelen ~= 0 then -- Still not empty, so we'll try again later
 363                                 if handler then
 364                                         handler.write = nil -- ... but no further writing allowed
 365                                 end
 366                                 toclose = true
 367                                 return false
 368                         end
 369                 end
 370                 if socket then
 371                         _ = shutdown and shutdown( socket )
 372                         socket:close( )
 373                         _sendlistlen = removesocket( _sendlist, socket, _sendlistlen )
 374                         _socketlist[ socket ] = nil
 375                         socket = nil
 376                 else
 377                         out_put "server.lua: socket already closed"
 378                 end
 379                 if handler then
 380                         _writetimes[ handler ] = nil
 381                         _closelist[ handler ] = nil
 382                         local _handler = handler;
 383                         handler = nil
 384                         if disconnect then
 385                                 disconnect(_handler, err or false);
 386                                 disconnect = nil
 387                         end
 388                 end
 389                 if server then
 390                         server.remove( )
 391                 end
 392                 out_put "server.lua: closed client handler and removed socket from list"
 393                 return true
 394         end
 395         handler.ip = function( )
 396                 return ip
 397         end
 398         handler.serverport = function( )
 399                 return serverport
 400         end
 401         handler.clientport = function( )
 402                 return clientport
 403         end
 404         local write = function( self, data )
 405                 bufferlen = bufferlen + #data
 406                 if bufferlen > maxsendlen then
 407                         _closelist[ handler ] = "send buffer exceeded"   -- cannot close the client at the moment, have to wait to the end of the cycle
 408                         handler.write = idfalse -- dont write anymore
 409                         return false
 410                 elseif socket and not _sendlist[ socket ] then
 411                         _sendlistlen = addsocket(_sendlist, socket, _sendlistlen)
 412                 end
 413                 bufferqueuelen = bufferqueuelen + 1
 414                 bufferqueue[ bufferqueuelen ] = data
 415                 if handler then
 416                         _writetimes[ handler ] = _writetimes[ handler ] or _currenttime
 417                 end
 418                 return true
 419         end
 420         handler.write = write
 421         handler.bufferqueue = function( self )
 422                 return bufferqueue
 423         end
 424         handler.socket = function( self )
 425                 return socket
 426         end
 427         handler.set_mode = function( self, new )
 428                 pattern = new or pattern
 429                 return pattern
 430         end
 431         handler.set_send = function ( self, newsend )
 432                 send = newsend or send
 433                 return send
 434         end
 435         handler.bufferlen = function( self, readlen, sendlen )
 436                 maxsendlen = sendlen or maxsendlen
 437                 maxreadlen = readlen or maxreadlen
 438                 return bufferlen, maxreadlen, maxsendlen
 439         end
 440         --TODO: Deprecate
 441         handler.lock_read = function (self, switch)
 442                 if switch == true then
 443                         local tmp = _readlistlen
 444                         _readlistlen = removesocket( _readlist, socket, _readlistlen )
 445                         _readtimes[ handler ] = nil
 446                         if _readlistlen ~= tmp then
 447                                 noread = true
 448                         end
 449                 elseif switch == false then
 450                         if noread then
 451                                 noread = false
 452                                 _readlistlen = addsocket(_readlist, socket, _readlistlen)
 453                                 _readtimes[ handler ] = _currenttime
 454                         end
 455                 end
 456                 return noread
 457         end
 458         handler.pause = function (self)
 459                 return self:lock_read(true);
 460         end
 461         handler.resume = function (self)
 462                 return self:lock_read(false);
 463         end
 464         handler.lock = function( self, switch )
 465                 handler.lock_read (switch)
 466                 if switch == true then
 467                         handler.write = idfalse
 468                         local tmp = _sendlistlen
 469                         _sendlistlen = removesocket( _sendlist, socket, _sendlistlen )
 470                         _writetimes[ handler ] = nil
 471                         if _sendlistlen ~= tmp then
 472                                 nosend = true
 473                         end
 474                 elseif switch == false then
 475                         handler.write = write
 476                         if nosend then
 477                                 nosend = false
 478                                 write( "" )
 479                         end
 480                 end
 481                 return noread, nosend
 482         end
 483         local _readbuffer = function( ) -- this function reads data
 484                 local buffer, err, part = receive( socket, pattern )    -- receive buffer with "pattern"
 485                 if not err or (err == "wantread" or err == "timeout") then -- received something
 486                         local buffer = buffer or part or ""
 487                         local len = #buffer
 488                         if len > maxreadlen then
 489                                 handler:close( "receive buffer exceeded" )
 490                                 return false
 491                         end
 492                         local count = len * STAT_UNIT
 493                         readtraffic = readtraffic + count
 494                         _readtraffic = _readtraffic + count
 495                         _readtimes[ handler ] = _currenttime
 496                         --out_put( "server.lua: read data '", buffer:gsub("[^%w%p ]", "."), "', error: ", err )
 497                         return dispatch( handler, buffer, err )
 498                 else    -- connections was closed or fatal error
 499                         out_put( "server.lua: client ", tostring(ip), ":", tostring(clientport), " read error: ", tostring(err) )
 500                         fatalerror = true
 501                         _ = handler and handler:force_close( err )
 502                         return false
 503                 end
 504         end
 505         local _sendbuffer = function( ) -- this function sends data
 506                 local succ, err, byte, buffer, count;
 507                 if socket then
 508                         buffer = table_concat( bufferqueue, "", 1, bufferqueuelen )
 509                         succ, err, byte = send( socket, buffer, 1, bufferlen )
 510                         count = ( succ or byte or 0 ) * STAT_UNIT
 511                         sendtraffic = sendtraffic + count
 512                         _sendtraffic = _sendtraffic + count
 513                         for i = bufferqueuelen,1,-1 do
 514                                 bufferqueue[ i ] = nil
 515                         end
 516                         --out_put( "server.lua: sended '", buffer, "', bytes: ", tostring(succ), ", error: ", tostring(err), ", part: ", tostring(byte), ", to: ", tostring(ip), ":", tostring(clientport) )
 517                 else
 518                         succ, err, count = false, "unexpected close", 0;
 519                 end
 520                 if succ then    -- sending succesful
 521                         bufferqueuelen = 0
 522                         bufferlen = 0
 523                         _sendlistlen = removesocket( _sendlist, socket, _sendlistlen ) -- delete socket from writelist
 524                         _writetimes[ handler ] = nil
 525                         if drain then
 526                                 drain(handler)
 527                         end
 528                         _ = needtls and handler:starttls(nil)
 529                         _ = toclose and handler:force_close( )
 530                         return true
 531                 elseif byte and ( err == "timeout" or err == "wantwrite" ) then -- want write
 532                         buffer = string_sub( buffer, byte + 1, bufferlen ) -- new buffer
 533                         bufferqueue[ 1 ] = buffer        -- insert new buffer in queue
 534                         bufferqueuelen = 1
 535                         bufferlen = bufferlen - byte
 536                         _writetimes[ handler ] = _currenttime
 537                         return true
 538                 else    -- connection was closed during sending or fatal error
 539                         out_put( "server.lua: client ", tostring(ip), ":", tostring(clientport), " write error: ", tostring(err) )
 540                         fatalerror = true
 541                         _ = handler and handler:force_close( err )
 542                         return false
 543                 end
 544         end
 545
 546         -- Set the sslctx
 547         local handshake;
 548         function handler.set_sslctx(self, new_sslctx)
 549                 sslctx = new_sslctx;
 550                 local read, wrote
 551                 handshake = coroutine_wrap( function( client ) -- create handshake coroutine
 552                                 local err
 553                                 for i = 1, _maxsslhandshake do
 554                                         _sendlistlen = ( wrote and removesocket( _sendlist, client, _sendlistlen ) ) or _sendlistlen
 555                                         _readlistlen = ( read and removesocket( _readlist, client, _readlistlen ) ) or _readlistlen
 556                                         read, wrote = nil, nil
 557                                         _, err = client:dohandshake( )
 558                                         if not err then
 559                                                 out_put( "server.lua: ssl handshake done" )
 560                                                 handler.readbuffer = _readbuffer        -- when handshake is done, replace the handshake function with regular functions
 561                                                 handler.sendbuffer = _sendbuffer
 562                                                 _ = status and status( handler, "ssl-handshake-complete" )
 563                                                 if self.autostart_ssl and listeners.onconnect then
 564                                                         listeners.onconnect(self);
 565                                                 end
 566                                                 _readlistlen = addsocket(_readlist, client, _readlistlen)
 567                                                 return true
 568                                         else
 569                                                 if err == "wantwrite" then
 570                                                         _sendlistlen = addsocket(_sendlist, client, _sendlistlen)
 571                                                         wrote = true
 572                                                 elseif err == "wantread" then
 573                                                         _readlistlen = addsocket(_readlist, client, _readlistlen)
 574                                                         read = true
 575                                                 else
 576                                                         break;
 577                                                 end
 578                                                 err = nil;
 579                                                 coroutine_yield( ) -- handshake not finished
 580                                         end
 581                                 end
 582                                 out_put( "server.lua: ssl handshake error: ", tostring(err or "handshake too long") )
 583                                 _ = handler and handler:force_close("ssl handshake failed")
 584                                 return false, err -- handshake failed
 585                         end
 586                 )
 587         end
 588         if luasec then
 589                 handler.starttls = function( self, _sslctx)
 590                         if _sslctx then
 591                                 handler:set_sslctx(_sslctx);
 592                         end
 593                         if bufferqueuelen > 0 then
 594                                 out_put "server.lua: we need to do tls, but delaying until send buffer empty"
 595                                 needtls = true
 596                                 return
 597                         end
 598                         out_put( "server.lua: attempting to start tls on " .. tostring( socket ) )
 599                         local oldsocket, err = socket
 600                         socket, err = ssl_wrap( socket, sslctx )        -- wrap socket
 601                         if not socket then
 602                                 out_put( "server.lua: error while starting tls on client: ", tostring(err or "unknown error") )
 603                                 return nil, err -- fatal error
 604                         end
 605
 606                         socket:settimeout( 0 )
 607
 608                         -- add the new socket to our system
 609                         send = socket.send
 610                         receive = socket.receive
 611                         shutdown = id
 612                         _socketlist[ socket ] = handler
 613                         _readlistlen = addsocket(_readlist, socket, _readlistlen)
 614
 615                         -- remove traces of the old socket
 616                         _readlistlen = removesocket( _readlist, oldsocket, _readlistlen )
 617                         _sendlistlen = removesocket( _sendlist, oldsocket, _sendlistlen )
 618                         _socketlist[ oldsocket ] = nil
 619
 620                         handler.starttls = nil
 621                         needtls = nil
 622
 623                         -- Secure now (if handshake fails connection will close)
 624                         ssl = true
 625
 626                         handler.readbuffer = handshake
 627                         handler.sendbuffer = handshake
 628                         return handshake( socket ) -- do handshake
 629                 end
 630         end
 631
 632         handler.readbuffer = _readbuffer
 633         handler.sendbuffer = _sendbuffer
 634         send = socket.send
 635         receive = socket.receive
 636         shutdown = ( ssl and id ) or socket.shutdown
 637
 638         _socketlist[ socket ] = handler
 639         _readlistlen = addsocket(_readlist, socket, _readlistlen)
 640
 641         if sslctx and luasec then
 642                 out_put "server.lua: auto-starting ssl negotiation..."
 643                 handler.autostart_ssl = true;
 644                 local ok, err = handler:starttls(sslctx);
 645                 if ok == false then
 646                         return nil, nil, err
 647                 end
 648         end
 649
 650         return handler, socket
 651 end
 652
 653 id = function( )
 654 end
 655
 656 idfalse = function( )
 657         return false
 658 end
 659
 660 addsocket = function( list, socket, len )
 661         if not list[ socket ] then
 662                 len = len + 1
 663                 list[ len ] = socket
 664                 list[ socket ] = len
 665         end
 666         return len;
 667 end
 668
 669 removesocket = function( list, socket, len )    -- this function removes sockets from a list ( copied from copas )
 670         local pos = list[ socket ]
 671         if pos then
 672                 list[ socket ] = nil
 673                 local last = list[ len ]
 674                 list[ len ] = nil
 675                 if last ~= socket then
 676                         list[ last ] = pos
 677                         list[ pos ] = last
 678                 end
 679                 return len - 1
 680         end
 681         return len
 682 end
 683
 684 closesocket = function( socket )
 685         _sendlistlen = removesocket( _sendlist, socket, _sendlistlen )
 686         _readlistlen = removesocket( _readlist, socket, _readlistlen )
 687         _socketlist[ socket ] = nil
 688         socket:close( )
 689         --mem_free( )
 690 end
 691
 692 local function link(sender, receiver, buffersize)
 693         local sender_locked;
 694         local _sendbuffer = receiver.sendbuffer;
 695         function receiver.sendbuffer()
 696                 _sendbuffer();
 697                 if sender_locked and receiver.bufferlen() < buffersize then
 698                         sender:lock_read(false); -- Unlock now
 699                         sender_locked = nil;
 700                 end
 701         end
 702
 703         local _readbuffer = sender.readbuffer;
 704         function sender.readbuffer()
 705                 _readbuffer();
 706                 if not sender_locked and receiver.bufferlen() >= buffersize then
 707                         sender_locked = true;
 708                         sender:lock_read(true);
 709                 end
 710         end
 711 end
 712
 713 ----------------------------------// PUBLIC //--
 714
 715 addserver = function( addr, port, listeners, pattern, sslctx ) -- this function provides a way for other scripts to reg a server
 716         local err
 717         if type( listeners ) ~= "table" then
 718                 err = "invalid listener table"
 719         end
 720         if type( port ) ~= "number" or not ( port >= 0 and port <= 65535 ) then
 721                 err = "invalid port"
 722         elseif _server[ addr..":"..port ] then
 723                 err = "listeners on '[" .. addr .. "]:" .. port .. "' already exist"
 724         elseif sslctx and not luasec then
 725                 err = "luasec not found"
 726         end
 727         if err then
 728                 out_error( "server.lua, [", addr, "]:", port, ": ", err )
 729                 return nil, err
 730         end
 731         addr = addr or "*"
 732         local server, err = socket_bind( addr, port, _tcpbacklog )
 733         if err then
 734                 out_error( "server.lua, [", addr, "]:", port, ": ", err )
 735                 return nil, err
 736         end
 737         local handler, err = wrapserver( listeners, server, addr, port, pattern, sslctx ) -- wrap new server socket
 738         if not handler then
 739                 server:close( )
 740                 return nil, err
 741         end
 742         server:settimeout( 0 )
 743         _readlistlen = addsocket(_readlist, server, _readlistlen)
 744         _server[ addr..":"..port ] = handler
 745         _socketlist[ server ] = handler
 746         out_put( "server.lua: new "..(sslctx and "ssl " or "").."server listener on '[", addr, "]:", port, "'" )
 747         return handler
 748 end
 749
 750 getserver = function ( addr, port )
 751         return _server[ addr..":"..port ];
 752 end
 753
 754 removeserver = function( addr, port )
 755         local handler = _server[ addr..":"..port ]
 756         if not handler then
 757                 return nil, "no server found on '[" .. addr .. "]:" .. tostring( port ) .. "'"
 758         end
 759         handler:close( )
 760         _server[ addr..":"..port ] = nil
 761         return true
 762 end
 763
 764 closeall = function( )
 765         for _, handler in pairs( _socketlist ) do
 766                 handler:close( )
 767                 _socketlist[ _ ] = nil
 768         end
 769         _readlistlen = 0
 770         _sendlistlen = 0
 771         _timerlistlen = 0
 772         _server = { }
 773         _readlist = { }
 774         _sendlist = { }
 775         _timerlist = { }
 776         _socketlist = { }
 777         --mem_free( )
 778 end
 779
 780 getsettings = function( )
 781         return {
 782                 select_timeout = _selecttimeout;
 783                 select_sleep_time = _sleeptime;
 784                 tcp_backlog = _tcpbacklog;
 785                 max_send_buffer_size = _maxsendlen;
 786                 max_receive_buffer_size = _maxreadlen;
 787                 select_idle_check_interval = _checkinterval;
 788                 send_timeout = _sendtimeout;
 789                 read_timeout = _readtimeout;
 790                 max_connections = _maxselectlen;
 791                 max_ssl_handshake_roundtrips = _maxsslhandshake;
 792                 highest_allowed_fd = _maxfd;
 793         }
 794 end
 795
 796 changesettings = function( new )
 797         if type( new ) ~= "table" then
 798                 return nil, "invalid settings table"
 799         end
 800         _selecttimeout = tonumber( new.select_timeout ) or _selecttimeout
 801         _sleeptime = tonumber( new.select_sleep_time ) or _sleeptime
 802         _maxsendlen = tonumber( new.max_send_buffer_size ) or _maxsendlen
 803         _maxreadlen = tonumber( new.max_receive_buffer_size ) or _maxreadlen
 804         _checkinterval = tonumber( new.select_idle_check_interval ) or _checkinterval
 805         _tcpbacklog = tonumber( new.tcp_backlog ) or _tcpbacklog
 806         _sendtimeout = tonumber( new.send_timeout ) or _sendtimeout
 807         _readtimeout = tonumber( new.read_timeout ) or _readtimeout
 808         _maxselectlen = new.max_connections or _maxselectlen
 809         _maxsslhandshake = new.max_ssl_handshake_roundtrips or _maxsslhandshake
 810         _maxfd = new.highest_allowed_fd or _maxfd
 811         return true
 812 end
 813
 814 addtimer = function( listener )
 815         if type( listener ) ~= "function" then
 816                 return nil, "invalid listener function"
 817         end
 818         _timerlistlen = _timerlistlen + 1
 819         _timerlist[ _timerlistlen ] = listener
 820         return true
 821 end
 822
 823 stats = function( )
 824         return _readtraffic, _sendtraffic, _readlistlen, _sendlistlen, _timerlistlen
 825 end
 826
 827 local quitting;
 828
 829 local function setquitting(quit)
 830         quitting = not not quit;
 831 end
 832
 833 loop = function(once) -- this is the main loop of the program
 834         if quitting then return "quitting"; end
 835         if once then quitting = "once"; end
 836         local next_timer_time = math_huge;
 837         repeat
 838                 local read, write, err = socket_select( _readlist, _sendlist, math_min(_selecttimeout, next_timer_time) )
 839                 for i, socket in ipairs( write ) do -- send data waiting in writequeues
 840                         local handler = _socketlist[ socket ]
 841                         if handler then
 842                                 handler.sendbuffer( )
 843                         else
 844                                 closesocket( socket )
 845                                 out_put "server.lua: found no handler and closed socket (writelist)"    -- this should not happen
 846                         end
 847                 end
 848                 for i, socket in ipairs( read ) do -- receive data
 849                         local handler = _socketlist[ socket ]
 850                         if handler then
 851                                 handler.readbuffer( )
 852                         else
 853                                 closesocket( socket )
 854                                 out_put "server.lua: found no handler and closed socket (readlist)" -- this can happen
 855                         end
 856                 end
 857                 for handler, err in pairs( _closelist ) do
 858                         handler.disconnect( )( handler, err )
 859                         handler:force_close()    -- forced disconnect
 860                         _closelist[ handler ] = nil;
 861                 end
 862                 _currenttime = luasocket_gettime( )
 863
 864                 -- Check for socket timeouts
 865                 local difftime = os_difftime( _currenttime - _starttime )
 866                 if difftime > _checkinterval then
 867                         _starttime = _currenttime
 868                         for handler, timestamp in pairs( _writetimes ) do
 869                                 if os_difftime( _currenttime - timestamp ) > _sendtimeout then
 870                                         handler.disconnect( )( handler, "send timeout" )
 871                                         handler:force_close()    -- forced disconnect
 872                                 end
 873                         end
 874                         for handler, timestamp in pairs( _readtimes ) do
 875                                 if os_difftime( _currenttime - timestamp ) > _readtimeout then
 876                                         if not(handler.onreadtimeout) or handler:onreadtimeout() ~= true then
 877                                                 handler.disconnect( )( handler, "read timeout" )
 878                                                 handler:close( )        -- forced disconnect?
 879                                         end
 880                                 end
 881                         end
 882                 end
 883
 884                 -- Fire timers
 885                 if _currenttime - _timer >= math_min(next_timer_time, 1) then
 886                         next_timer_time = math_huge;
 887                         for i = 1, _timerlistlen do
 888                                 local t = _timerlist[ i ]( _currenttime ) -- fire timers
 889                                 if t then next_timer_time = math_min(next_timer_time, t); end
 890                         end
 891                         _timer = _currenttime
 892                 else
 893                         next_timer_time = next_timer_time - (_currenttime - _timer);
 894                 end
 895
 896                 -- wait some time (0 by default)
 897                 socket_sleep( _sleeptime )
 898         until quitting;
 899         if once and quitting == "once" then quitting = nil; return; end
 900         return "quitting"
 901 end
 902
 903 local function step()
 904         return loop(true);
 905 end
 906
 907 local function get_backend()
 908         return "select";
 909 end
 910
 911 --// EXPERIMENTAL //--
 912
 913 local wrapclient = function( socket, ip, serverport, listeners, pattern, sslctx )
 914         local handler, socket, err = wrapconnection( nil, listeners, socket, ip, serverport, "clientport", pattern, sslctx )
 915         if not handler then return nil, err end
 916         _socketlist[ socket ] = handler
 917         if not sslctx then
 918                 _sendlistlen = addsocket(_sendlist, socket, _sendlistlen)
 919                 if listeners.onconnect then
 920                         -- When socket is writeable, call onconnect
 921                         local _sendbuffer = handler.sendbuffer;
 922                         handler.sendbuffer = function ()
 923                                 handler.sendbuffer = _sendbuffer;
 924                                 listeners.onconnect(handler);
 925                                 return _sendbuffer(); -- Send any queued outgoing data
 926                         end
 927                 end
 928         end
 929         return handler, socket
 930 end
 931
 932 local addclient = function( address, port, listeners, pattern, sslctx )
 933         local client, err = luasocket.tcp( )
 934         if err then
 935                 return nil, err
 936         end
 937         client:settimeout( 0 )
 938         _, err = client:connect( address, port )
 939         if err then -- try again
 940                 return wrapclient( client, address, port, listeners, pattern, sslctx )
 941         else
 942                 return wrapconnection( nil, listeners, client, address, port, "clientport", pattern, sslctx )
 943         end
 944 end
 945
 946 --// EXPERIMENTAL //--
 947
 948 ----------------------------------// BEGIN //--
 949
 950 use "setmetatable" ( _socketlist, { __mode = "k" } )
 951 use "setmetatable" ( _readtimes, { __mode = "k" } )
 952 use "setmetatable" ( _writetimes, { __mode = "k" } )
 953
 954 _timer = luasocket_gettime( )
 955 _starttime = luasocket_gettime( )
 956
 957 local function setlogger(new_logger)
 958         local old_logger = log;
 959         if new_logger then
 960                 log = new_logger;
 961         end
 962         return old_logger;
 963 end
 964
 965 ----------------------------------// PUBLIC INTERFACE //--
 966
 967 return {
 968         _addtimer = addtimer,
 969
 970         addclient = addclient,
 971         wrapclient = wrapclient,
 972
 973         loop = loop,
 974         link = link,
 975         step = step,
 976         stats = stats,
 977         closeall = closeall,
 978         addserver = addserver,
 979         getserver = getserver,
 980         setlogger = setlogger,
 981         getsettings = getsettings,
 982         setquitting = setquitting,
 983         removeserver = removeserver,
 984         get_backend = get_backend,
 985         changesettings = changesettings,
 986 }