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         handler.port = handler.clientport -- COMPAT server_event
 405         local write = function( self, data )
 406                 bufferlen = bufferlen + #data
 407                 if bufferlen > maxsendlen then
 408                         _closelist[ handler ] = "send buffer exceeded"   -- cannot close the client at the moment, have to wait to the end of the cycle
 409                         handler.write = idfalse -- dont write anymore
 410                         return false
 411                 elseif socket and not _sendlist[ socket ] then
 412                         _sendlistlen = addsocket(_sendlist, socket, _sendlistlen)
 413                 end
 414                 bufferqueuelen = bufferqueuelen + 1
 415                 bufferqueue[ bufferqueuelen ] = data
 416                 if handler then
 417                         _writetimes[ handler ] = _writetimes[ handler ] or _currenttime
 418                 end
 419                 return true
 420         end
 421         handler.write = write
 422         handler.bufferqueue = function( self )
 423                 return bufferqueue
 424         end
 425         handler.socket = function( self )
 426                 return socket
 427         end
 428         handler.set_mode = function( self, new )
 429                 pattern = new or pattern
 430                 return pattern
 431         end
 432         handler.set_send = function ( self, newsend )
 433                 send = newsend or send
 434                 return send
 435         end
 436         handler.bufferlen = function( self, readlen, sendlen )
 437                 maxsendlen = sendlen or maxsendlen
 438                 maxreadlen = readlen or maxreadlen
 439                 return bufferlen, maxreadlen, maxsendlen
 440         end
 441         --TODO: Deprecate
 442         handler.lock_read = function (self, switch)
 443                 if switch == true then
 444                         local tmp = _readlistlen
 445                         _readlistlen = removesocket( _readlist, socket, _readlistlen )
 446                         _readtimes[ handler ] = nil
 447                         if _readlistlen ~= tmp then
 448                                 noread = true
 449                         end
 450                 elseif switch == false then
 451                         if noread then
 452                                 noread = false
 453                                 _readlistlen = addsocket(_readlist, socket, _readlistlen)
 454                                 _readtimes[ handler ] = _currenttime
 455                         end
 456                 end
 457                 return noread
 458         end
 459         handler.pause = function (self)
 460                 return self:lock_read(true);
 461         end
 462         handler.resume = function (self)
 463                 return self:lock_read(false);
 464         end
 465         handler.lock = function( self, switch )
 466                 handler.lock_read (switch)
 467                 if switch == true then
 468                         handler.write = idfalse
 469                         local tmp = _sendlistlen
 470                         _sendlistlen = removesocket( _sendlist, socket, _sendlistlen )
 471                         _writetimes[ handler ] = nil
 472                         if _sendlistlen ~= tmp then
 473                                 nosend = true
 474                         end
 475                 elseif switch == false then
 476                         handler.write = write
 477                         if nosend then
 478                                 nosend = false
 479                                 write( "" )
 480                         end
 481                 end
 482                 return noread, nosend
 483         end
 484         local _readbuffer = function( ) -- this function reads data
 485                 local buffer, err, part = receive( socket, pattern )    -- receive buffer with "pattern"
 486                 if not err or (err == "wantread" or err == "timeout") then -- received something
 487                         local buffer = buffer or part or ""
 488                         local len = #buffer
 489                         if len > maxreadlen then
 490                                 handler:close( "receive buffer exceeded" )
 491                                 return false
 492                         end
 493                         local count = len * STAT_UNIT
 494                         readtraffic = readtraffic + count
 495                         _readtraffic = _readtraffic + count
 496                         _readtimes[ handler ] = _currenttime
 497                         --out_put( "server.lua: read data '", buffer:gsub("[^%w%p ]", "."), "', error: ", err )
 498                         return dispatch( handler, buffer, err )
 499                 else    -- connections was closed or fatal error
 500                         out_put( "server.lua: client ", tostring(ip), ":", tostring(clientport), " read error: ", tostring(err) )
 501                         fatalerror = true
 502                         _ = handler and handler:force_close( err )
 503                         return false
 504                 end
 505         end
 506         local _sendbuffer = function( ) -- this function sends data
 507                 local succ, err, byte, buffer, count;
 508                 if socket then
 509                         buffer = table_concat( bufferqueue, "", 1, bufferqueuelen )
 510                         succ, err, byte = send( socket, buffer, 1, bufferlen )
 511                         count = ( succ or byte or 0 ) * STAT_UNIT
 512                         sendtraffic = sendtraffic + count
 513                         _sendtraffic = _sendtraffic + count
 514                         for i = bufferqueuelen,1,-1 do
 515                                 bufferqueue[ i ] = nil
 516                         end
 517                         --out_put( "server.lua: sended '", buffer, "', bytes: ", tostring(succ), ", error: ", tostring(err), ", part: ", tostring(byte), ", to: ", tostring(ip), ":", tostring(clientport) )
 518                 else
 519                         succ, err, count = false, "unexpected close", 0;
 520                 end
 521                 if succ then    -- sending succesful
 522                         bufferqueuelen = 0
 523                         bufferlen = 0
 524                         _sendlistlen = removesocket( _sendlist, socket, _sendlistlen ) -- delete socket from writelist
 525                         _writetimes[ handler ] = nil
 526                         if drain then
 527                                 drain(handler)
 528                         end
 529                         _ = needtls and handler:starttls(nil)
 530                         _ = toclose and handler:force_close( )
 531                         return true
 532                 elseif byte and ( err == "timeout" or err == "wantwrite" ) then -- want write
 533                         buffer = string_sub( buffer, byte + 1, bufferlen ) -- new buffer
 534                         bufferqueue[ 1 ] = buffer        -- insert new buffer in queue
 535                         bufferqueuelen = 1
 536                         bufferlen = bufferlen - byte
 537                         _writetimes[ handler ] = _currenttime
 538                         return true
 539                 else    -- connection was closed during sending or fatal error
 540                         out_put( "server.lua: client ", tostring(ip), ":", tostring(clientport), " write error: ", tostring(err) )
 541                         fatalerror = true
 542                         _ = handler and handler:force_close( err )
 543                         return false
 544                 end
 545         end
 546
 547         -- Set the sslctx
 548         local handshake;
 549         function handler.set_sslctx(self, new_sslctx)
 550                 sslctx = new_sslctx;
 551                 local read, wrote
 552                 handshake = coroutine_wrap( function( client ) -- create handshake coroutine
 553                                 local err
 554                                 for i = 1, _maxsslhandshake do
 555                                         _sendlistlen = ( wrote and removesocket( _sendlist, client, _sendlistlen ) ) or _sendlistlen
 556                                         _readlistlen = ( read and removesocket( _readlist, client, _readlistlen ) ) or _readlistlen
 557                                         read, wrote = nil, nil
 558                                         _, err = client:dohandshake( )
 559                                         if not err then
 560                                                 out_put( "server.lua: ssl handshake done" )
 561                                                 handler.readbuffer = _readbuffer        -- when handshake is done, replace the handshake function with regular functions
 562                                                 handler.sendbuffer = _sendbuffer
 563                                                 _ = status and status( handler, "ssl-handshake-complete" )
 564                                                 if self.autostart_ssl and listeners.onconnect then
 565                                                         listeners.onconnect(self);
 566                                                 end
 567                                                 _readlistlen = addsocket(_readlist, client, _readlistlen)
 568                                                 return true
 569                                         else
 570                                                 if err == "wantwrite" then
 571                                                         _sendlistlen = addsocket(_sendlist, client, _sendlistlen)
 572                                                         wrote = true
 573                                                 elseif err == "wantread" then
 574                                                         _readlistlen = addsocket(_readlist, client, _readlistlen)
 575                                                         read = true
 576                                                 else
 577                                                         break;
 578                                                 end
 579                                                 err = nil;
 580                                                 coroutine_yield( ) -- handshake not finished
 581                                         end
 582                                 end
 583                                 out_put( "server.lua: ssl handshake error: ", tostring(err or "handshake too long") )
 584                                 _ = handler and handler:force_close("ssl handshake failed")
 585                                 return false, err -- handshake failed
 586                         end
 587                 )
 588         end
 589         if luasec then
 590                 handler.starttls = function( self, _sslctx)
 591                         if _sslctx then
 592                                 handler:set_sslctx(_sslctx);
 593                         end
 594                         if bufferqueuelen > 0 then
 595                                 out_put "server.lua: we need to do tls, but delaying until send buffer empty"
 596                                 needtls = true
 597                                 return
 598                         end
 599                         out_put( "server.lua: attempting to start tls on " .. tostring( socket ) )
 600                         local oldsocket, err = socket
 601                         socket, err = ssl_wrap( socket, sslctx )        -- wrap socket
 602                         if not socket then
 603                                 out_put( "server.lua: error while starting tls on client: ", tostring(err or "unknown error") )
 604                                 return nil, err -- fatal error
 605                         end
 606
 607                         socket:settimeout( 0 )
 608
 609                         -- add the new socket to our system
 610                         send = socket.send
 611                         receive = socket.receive
 612                         shutdown = id
 613                         _socketlist[ socket ] = handler
 614                         _readlistlen = addsocket(_readlist, socket, _readlistlen)
 615
 616                         -- remove traces of the old socket
 617                         _readlistlen = removesocket( _readlist, oldsocket, _readlistlen )
 618                         _sendlistlen = removesocket( _sendlist, oldsocket, _sendlistlen )
 619                         _socketlist[ oldsocket ] = nil
 620
 621                         handler.starttls = nil
 622                         needtls = nil
 623
 624                         -- Secure now (if handshake fails connection will close)
 625                         ssl = true
 626
 627                         handler.readbuffer = handshake
 628                         handler.sendbuffer = handshake
 629                         return handshake( socket ) -- do handshake
 630                 end
 631         end
 632
 633         handler.readbuffer = _readbuffer
 634         handler.sendbuffer = _sendbuffer
 635         send = socket.send
 636         receive = socket.receive
 637         shutdown = ( ssl and id ) or socket.shutdown
 638
 639         _socketlist[ socket ] = handler
 640         _readlistlen = addsocket(_readlist, socket, _readlistlen)
 641
 642         if sslctx and luasec then
 643                 out_put "server.lua: auto-starting ssl negotiation..."
 644                 handler.autostart_ssl = true;
 645                 local ok, err = handler:starttls(sslctx);
 646                 if ok == false then
 647                         return nil, nil, err
 648                 end
 649         end
 650
 651         return handler, socket
 652 end
 653
 654 id = function( )
 655 end
 656
 657 idfalse = function( )
 658         return false
 659 end
 660
 661 addsocket = function( list, socket, len )
 662         if not list[ socket ] then
 663                 len = len + 1
 664                 list[ len ] = socket
 665                 list[ socket ] = len
 666         end
 667         return len;
 668 end
 669
 670 removesocket = function( list, socket, len )    -- this function removes sockets from a list ( copied from copas )
 671         local pos = list[ socket ]
 672         if pos then
 673                 list[ socket ] = nil
 674                 local last = list[ len ]
 675                 list[ len ] = nil
 676                 if last ~= socket then
 677                         list[ last ] = pos
 678                         list[ pos ] = last
 679                 end
 680                 return len - 1
 681         end
 682         return len
 683 end
 684
 685 closesocket = function( socket )
 686         _sendlistlen = removesocket( _sendlist, socket, _sendlistlen )
 687         _readlistlen = removesocket( _readlist, socket, _readlistlen )
 688         _socketlist[ socket ] = nil
 689         socket:close( )
 690         --mem_free( )
 691 end
 692
 693 local function link(sender, receiver, buffersize)
 694         local sender_locked;
 695         local _sendbuffer = receiver.sendbuffer;
 696         function receiver.sendbuffer()
 697                 _sendbuffer();
 698                 if sender_locked and receiver.bufferlen() < buffersize then
 699                         sender:lock_read(false); -- Unlock now
 700                         sender_locked = nil;
 701                 end
 702         end
 703
 704         local _readbuffer = sender.readbuffer;
 705         function sender.readbuffer()
 706                 _readbuffer();
 707                 if not sender_locked and receiver.bufferlen() >= buffersize then
 708                         sender_locked = true;
 709                         sender:lock_read(true);
 710                 end
 711         end
 712 end
 713
 714 ----------------------------------// PUBLIC //--
 715
 716 addserver = function( addr, port, listeners, pattern, sslctx ) -- this function provides a way for other scripts to reg a server
 717         local err
 718         if type( listeners ) ~= "table" then
 719                 err = "invalid listener table"
 720         end
 721         if type( port ) ~= "number" or not ( port >= 0 and port <= 65535 ) then
 722                 err = "invalid port"
 723         elseif _server[ addr..":"..port ] then
 724                 err = "listeners on '[" .. addr .. "]:" .. port .. "' already exist"
 725         elseif sslctx and not luasec then
 726                 err = "luasec not found"
 727         end
 728         if err then
 729                 out_error( "server.lua, [", addr, "]:", port, ": ", err )
 730                 return nil, err
 731         end
 732         addr = addr or "*"
 733         local server, err = socket_bind( addr, port, _tcpbacklog )
 734         if err then
 735                 out_error( "server.lua, [", addr, "]:", port, ": ", err )
 736                 return nil, err
 737         end
 738         local handler, err = wrapserver( listeners, server, addr, port, pattern, sslctx ) -- wrap new server socket
 739         if not handler then
 740                 server:close( )
 741                 return nil, err
 742         end
 743         server:settimeout( 0 )
 744         _readlistlen = addsocket(_readlist, server, _readlistlen)
 745         _server[ addr..":"..port ] = handler
 746         _socketlist[ server ] = handler
 747         out_put( "server.lua: new "..(sslctx and "ssl " or "").."server listener on '[", addr, "]:", port, "'" )
 748         return handler
 749 end
 750
 751 getserver = function ( addr, port )
 752         return _server[ addr..":"..port ];
 753 end
 754
 755 removeserver = function( addr, port )
 756         local handler = _server[ addr..":"..port ]
 757         if not handler then
 758                 return nil, "no server found on '[" .. addr .. "]:" .. tostring( port ) .. "'"
 759         end
 760         handler:close( )
 761         _server[ addr..":"..port ] = nil
 762         return true
 763 end
 764
 765 closeall = function( )
 766         for _, handler in pairs( _socketlist ) do
 767                 handler:close( )
 768                 _socketlist[ _ ] = nil
 769         end
 770         _readlistlen = 0
 771         _sendlistlen = 0
 772         _timerlistlen = 0
 773         _server = { }
 774         _readlist = { }
 775         _sendlist = { }
 776         _timerlist = { }
 777         _socketlist = { }
 778         --mem_free( )
 779 end
 780
 781 getsettings = function( )
 782         return {
 783                 select_timeout = _selecttimeout;
 784                 select_sleep_time = _sleeptime;
 785                 tcp_backlog = _tcpbacklog;
 786                 max_send_buffer_size = _maxsendlen;
 787                 max_receive_buffer_size = _maxreadlen;
 788                 select_idle_check_interval = _checkinterval;
 789                 send_timeout = _sendtimeout;
 790                 read_timeout = _readtimeout;
 791                 max_connections = _maxselectlen;
 792                 max_ssl_handshake_roundtrips = _maxsslhandshake;
 793                 highest_allowed_fd = _maxfd;
 794         }
 795 end
 796
 797 changesettings = function( new )
 798         if type( new ) ~= "table" then
 799                 return nil, "invalid settings table"
 800         end
 801         _selecttimeout = tonumber( new.select_timeout ) or _selecttimeout
 802         _sleeptime = tonumber( new.select_sleep_time ) or _sleeptime
 803         _maxsendlen = tonumber( new.max_send_buffer_size ) or _maxsendlen
 804         _maxreadlen = tonumber( new.max_receive_buffer_size ) or _maxreadlen
 805         _checkinterval = tonumber( new.select_idle_check_interval ) or _checkinterval
 806         _tcpbacklog = tonumber( new.tcp_backlog ) or _tcpbacklog
 807         _sendtimeout = tonumber( new.send_timeout ) or _sendtimeout
 808         _readtimeout = tonumber( new.read_timeout ) or _readtimeout
 809         _maxselectlen = new.max_connections or _maxselectlen
 810         _maxsslhandshake = new.max_ssl_handshake_roundtrips or _maxsslhandshake
 811         _maxfd = new.highest_allowed_fd or _maxfd
 812         return true
 813 end
 814
 815 addtimer = function( listener )
 816         if type( listener ) ~= "function" then
 817                 return nil, "invalid listener function"
 818         end
 819         _timerlistlen = _timerlistlen + 1
 820         _timerlist[ _timerlistlen ] = listener
 821         return true
 822 end
 823
 824 stats = function( )
 825         return _readtraffic, _sendtraffic, _readlistlen, _sendlistlen, _timerlistlen
 826 end
 827
 828 local quitting;
 829
 830 local function setquitting(quit)
 831         quitting = not not quit;
 832 end
 833
 834 loop = function(once) -- this is the main loop of the program
 835         if quitting then return "quitting"; end
 836         if once then quitting = "once"; end
 837         local next_timer_time = math_huge;
 838         repeat
 839                 local read, write, err = socket_select( _readlist, _sendlist, math_min(_selecttimeout, next_timer_time) )
 840                 for i, socket in ipairs( write ) do -- send data waiting in writequeues
 841                         local handler = _socketlist[ socket ]
 842                         if handler then
 843                                 handler.sendbuffer( )
 844                         else
 845                                 closesocket( socket )
 846                                 out_put "server.lua: found no handler and closed socket (writelist)"    -- this should not happen
 847                         end
 848                 end
 849                 for i, socket in ipairs( read ) do -- receive data
 850                         local handler = _socketlist[ socket ]
 851                         if handler then
 852                                 handler.readbuffer( )
 853                         else
 854                                 closesocket( socket )
 855                                 out_put "server.lua: found no handler and closed socket (readlist)" -- this can happen
 856                         end
 857                 end
 858                 for handler, err in pairs( _closelist ) do
 859                         handler.disconnect( )( handler, err )
 860                         handler:force_close()    -- forced disconnect
 861                         _closelist[ handler ] = nil;
 862                 end
 863                 _currenttime = luasocket_gettime( )
 864
 865                 -- Check for socket timeouts
 866                 local difftime = os_difftime( _currenttime - _starttime )
 867                 if difftime > _checkinterval then
 868                         _starttime = _currenttime
 869                         for handler, timestamp in pairs( _writetimes ) do
 870                                 if os_difftime( _currenttime - timestamp ) > _sendtimeout then
 871                                         handler.disconnect( )( handler, "send timeout" )
 872                                         handler:force_close()    -- forced disconnect
 873                                 end
 874                         end
 875                         for handler, timestamp in pairs( _readtimes ) do
 876                                 if os_difftime( _currenttime - timestamp ) > _readtimeout then
 877                                         if not(handler.onreadtimeout) or handler:onreadtimeout() ~= true then
 878                                                 handler.disconnect( )( handler, "read timeout" )
 879                                                 handler:close( )        -- forced disconnect?
 880                                         end
 881                                 end
 882                         end
 883                 end
 884
 885                 -- Fire timers
 886                 if _currenttime - _timer >= math_min(next_timer_time, 1) then
 887                         next_timer_time = math_huge;
 888                         for i = 1, _timerlistlen do
 889                                 local t = _timerlist[ i ]( _currenttime ) -- fire timers
 890                                 if t then next_timer_time = math_min(next_timer_time, t); end
 891                         end
 892                         _timer = _currenttime
 893                 else
 894                         next_timer_time = next_timer_time - (_currenttime - _timer);
 895                 end
 896
 897                 -- wait some time (0 by default)
 898                 socket_sleep( _sleeptime )
 899         until quitting;
 900         if once and quitting == "once" then quitting = nil; return; end
 901         return "quitting"
 902 end
 903
 904 local function step()
 905         return loop(true);
 906 end
 907
 908 local function get_backend()
 909         return "select";
 910 end
 911
 912 --// EXPERIMENTAL //--
 913
 914 local wrapclient = function( socket, ip, serverport, listeners, pattern, sslctx )
 915         local handler, socket, err = wrapconnection( nil, listeners, socket, ip, serverport, "clientport", pattern, sslctx )
 916         if not handler then return nil, err end
 917         _socketlist[ socket ] = handler
 918         if not sslctx then
 919                 _sendlistlen = addsocket(_sendlist, socket, _sendlistlen)
 920                 if listeners.onconnect then
 921                         -- When socket is writeable, call onconnect
 922                         local _sendbuffer = handler.sendbuffer;
 923                         handler.sendbuffer = function ()
 924                                 handler.sendbuffer = _sendbuffer;
 925                                 listeners.onconnect(handler);
 926                                 return _sendbuffer(); -- Send any queued outgoing data
 927                         end
 928                 end
 929         end
 930         return handler, socket
 931 end
 932
 933 local addclient = function( address, port, listeners, pattern, sslctx )
 934         local client, err = luasocket.tcp( )
 935         if err then
 936                 return nil, err
 937         end
 938         client:settimeout( 0 )
 939         _, err = client:connect( address, port )
 940         if err then -- try again
 941                 return wrapclient( client, address, port, listeners, pattern, sslctx )
 942         else
 943                 return wrapconnection( nil, listeners, client, address, port, "clientport", pattern, sslctx )
 944         end
 945 end
 946
 947 --// EXPERIMENTAL //--
 948
 949 ----------------------------------// BEGIN //--
 950
 951 use "setmetatable" ( _socketlist, { __mode = "k" } )
 952 use "setmetatable" ( _readtimes, { __mode = "k" } )
 953 use "setmetatable" ( _writetimes, { __mode = "k" } )
 954
 955 _timer = luasocket_gettime( )
 956 _starttime = luasocket_gettime( )
 957
 958 local function setlogger(new_logger)
 959         local old_logger = log;
 960         if new_logger then
 961                 log = new_logger;
 962         end
 963         return old_logger;
 964 end
 965
 966 ----------------------------------// PUBLIC INTERFACE //--
 967
 968 return {
 969         _addtimer = addtimer,
 970
 971         addclient = addclient,
 972         wrapclient = wrapclient,
 973
 974         loop = loop,
 975         link = link,
 976         step = step,
 977         stats = stats,
 978         closeall = closeall,
 979         addserver = addserver,
 980         getserver = getserver,
 981         setlogger = setlogger,
 982         getsettings = getsettings,
 983         setquitting = setquitting,
 984         removeserver = removeserver,
 985         get_backend = get_backend,
 986         changesettings = changesettings,
 987 }