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                         -- to do some of the above, use timeout events or something what will called from outside
  10                         -- dont let garbagecollect eventcallbacks, as long they are running
  11                         -- when using luasec, there are 4 cases of timeout errors: wantread or wantwrite during reading or writing
  12
  13 --]]
  14
  15 local SCRIPT_NAME           = "server_event.lua"
  16 local SCRIPT_VERSION        = "0.05"
  17 local SCRIPT_AUTHOR         = "blastbeat"
  18 local LAST_MODIFIED         = "2009/11/20"
  19
  20 local cfg = {
  21         MAX_CONNECTIONS       = 100000,  -- max per server connections (use "ulimit -n" on *nix)
  22         MAX_HANDSHAKE_ATTEMPTS= 1000,  -- attempts to finish ssl handshake
  23         HANDSHAKE_TIMEOUT     = 60,  -- timeout in seconds per handshake attempt
  24         MAX_READ_LENGTH       = 1024 * 1024 * 1024 * 1024,  -- max bytes allowed to read from sockets
  25         MAX_SEND_LENGTH       = 1024 * 1024 * 1024 * 1024,  -- max bytes size of write buffer (for writing on sockets)
  26         ACCEPT_QUEUE          = 128,  -- might influence the length of the pending sockets queue
  27         ACCEPT_DELAY          = 10,  -- seconds to wait until the next attempt of a full server to accept
  28         READ_TIMEOUT          = 60 * 60 * 6,  -- timeout in seconds for read data from socket
  29         WRITE_TIMEOUT         = 180,  -- timeout in seconds for write data on socket
  30         CONNECT_TIMEOUT       = 20,  -- timeout in seconds for connection attempts
  31         CLEAR_DELAY           = 5,  -- seconds to wait for clearing interface list (and calling ondisconnect listeners)
  32         DEBUG                 = true,  -- show debug messages
  33 }
  34
  35 local function use(x) return rawget(_G, x); end
  36 local ipairs = use "ipairs"
  37 local string = use "string"
  38 local select = use "select"
  39 local require = use "require"
  40 local tostring = use "tostring"
  41 local coroutine = use "coroutine"
  42 local setmetatable = use "setmetatable"
  43
  44 local t_insert = table.insert
  45 local t_concat = table.concat
  46
  47 local has_luasec, ssl = pcall ( require , "ssl" )
  48 local socket = use "socket" or require "socket"
  49 local getaddrinfo = socket.dns.getaddrinfo
  50
  51 local log = require ("util.logger").init("socket")
  52
  53 local function debug(...)
  54         return log("debug", ("%s "):rep(select('#', ...)), ...)
  55 end
  56 local vdebug = debug;
  57
  58 local bitor = ( function( ) -- thx Rici Lake
  59         local hasbit = function( x, p )
  60                 return x % ( p + p ) >= p
  61         end
  62         return function( x, y )
  63                 local p = 1
  64                 local z = 0
  65                 local limit = x > y and x or y
  66                 while p <= limit do
  67                         if hasbit( x, p ) or hasbit( y, p ) then
  68                                 z = z + p
  69                         end
  70                         p = p + p
  71                 end
  72                 return z
  73         end
  74 end )( )
  75
  76 local event = require "luaevent.core"
  77 local base = event.new( )
  78 local EV_READ = event.EV_READ
  79 local EV_WRITE = event.EV_WRITE
  80 local EV_TIMEOUT = event.EV_TIMEOUT
  81 local EV_SIGNAL = event.EV_SIGNAL
  82
  83 local EV_READWRITE = bitor( EV_READ, EV_WRITE )
  84
  85 local interfacelist = ( function( )  -- holds the interfaces for sockets
  86         local array = { }
  87         local len = 0
  88         return function( method, arg )
  89                 if "add" == method then
  90                         len = len + 1
  91                         array[ len ] = arg
  92                         arg:_position( len )
  93                         return len
  94                 elseif "delete" == method then
  95                         if len <= 0 then
  96                                 return nil, "array is already empty"
  97                         end
  98                         local position = arg:_position()  -- get position in array
  99                         if position ~= len then
 100                                 local interface = array[ len ]  -- get last interface
 101                                 array[ position ] = interface  -- copy it into free position
 102                                 array[ len ] = nil  -- free last position
 103                                 interface:_position( position )  -- set new position in array
 104                         else  -- free last position
 105                                 array[ len ] = nil
 106                         end
 107                         len = len - 1
 108                         return len
 109                 else
 110                         return array
 111                 end
 112         end
 113 end )( )
 114
 115 -- Client interface methods
 116 local interface_mt
 117 do
 118         interface_mt = {}; interface_mt.__index = interface_mt;
 119
 120         local addevent = base.addevent
 121         local coroutine_wrap, coroutine_yield = coroutine.wrap,coroutine.yield
 122
 123         -- Private methods
 124         function interface_mt:_position(new_position)
 125                         self.position = new_position or self.position
 126                         return self.position;
 127         end
 128         function interface_mt:_close()
 129                 return self:_destroy();
 130         end
 131
 132         function interface_mt:_start_connection(plainssl) -- should be called from addclient
 133                         local callback = function( event )
 134                                 if EV_TIMEOUT == event then  -- timeout during connection
 135                                         self.fatalerror = "connection timeout"
 136                                         self:ontimeout()  -- call timeout listener
 137                                         self:_close()
 138                                         debug( "new connection failed. id:", self.id, "error:", self.fatalerror )
 139                                 else
 140                                         if plainssl and has_luasec then  -- start ssl session
 141                                                 self:starttls(self._sslctx, true)
 142                                         else  -- normal connection
 143                                                 self:_start_session(true)
 144                                         end
 145                                         debug( "new connection established. id:", self.id )
 146                                 end
 147                                 self.eventconnect = nil
 148                                 return -1
 149                         end
 150                         self.eventconnect = addevent( base, self.conn, EV_WRITE, callback, cfg.CONNECT_TIMEOUT )
 151                         return true
 152         end
 153         function interface_mt:_start_session(call_onconnect) -- new session, for example after startssl
 154                 if self.type == "client" then
 155                         local callback = function( )
 156                                 self:_lock( false,  false, false )
 157                                 --vdebug( "start listening on client socket with id:", self.id )
 158                                 self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
 159                                 if call_onconnect then
 160                                         self:onconnect()
 161                                 end
 162                                 self.eventsession = nil
 163                                 return -1
 164                         end
 165                         self.eventsession = addevent( base, nil, EV_TIMEOUT, callback, 0 )
 166                 else
 167                         self:_lock( false )
 168                         --vdebug( "start listening on server socket with id:", self.id )
 169                         self.eventread = addevent( base, self.conn, EV_READ, self.readcallback )  -- register callback
 170                 end
 171                 return true
 172         end
 173         function interface_mt:_start_ssl(call_onconnect) -- old socket will be destroyed, therefore we have to close read/write events first
 174                         --vdebug( "starting ssl session with client id:", self.id )
 175                         local _
 176                         _ = self.eventread and self.eventread:close( )  -- close events; this must be called outside of the event callbacks!
 177                         _ = self.eventwrite and self.eventwrite:close( )
 178                         self.eventread, self.eventwrite = nil, nil
 179                         local err
 180                         self.conn, err = ssl.wrap( self.conn, self._sslctx )
 181                         if err then
 182                                 self.fatalerror = err
 183                                 self.conn = nil  -- cannot be used anymore
 184                                 if call_onconnect then
 185                                         self.ondisconnect = nil  -- dont call this when client isnt really connected
 186                                 end
 187                                 self:_close()
 188                                 debug( "fatal error while ssl wrapping:", err )
 189                                 return false
 190                         end
 191                         self.conn:settimeout( 0 )  -- set non blocking
 192                         local handshakecallback = coroutine_wrap(
 193                                 function( event )
 194                                         local _, err
 195                                         local attempt = 0
 196                                         local maxattempt = cfg.MAX_HANDSHAKE_ATTEMPTS
 197                                         while attempt < maxattempt do  -- no endless loop
 198                                                 attempt = attempt + 1
 199                                                 debug( "ssl handshake of client with id:"..tostring(self)..", attempt:"..attempt )
 200                                                 if attempt > maxattempt then
 201                                                         self.fatalerror = "max handshake attempts exceeded"
 202                                                 elseif EV_TIMEOUT == event then
 203                                                         self.fatalerror = "timeout during handshake"
 204                                                 else
 205                                                         _, err = self.conn:dohandshake( )
 206                                                         if not err then
 207                                                                 self:_lock( false, false, false )  -- unlock the interface; sending, closing etc allowed
 208                                                                 self.send = self.conn.send  -- caching table lookups with new client object
 209                                                                 self.receive = self.conn.receive
 210                                                                 if not call_onconnect then  -- trigger listener
 211                                                                         self:onstatus("ssl-handshake-complete");
 212                                                                 end
 213                                                                 self:_start_session( call_onconnect )
 214                                                                 debug( "ssl handshake done" )
 215                                                                 self.eventhandshake = nil
 216                                                                 return -1
 217                                                         end
 218                                                         if err == "wantwrite" then
 219                                                                 event = EV_WRITE
 220                                                         elseif err == "wantread" then
 221                                                                 event = EV_READ
 222                                                         else
 223                                                                 debug( "ssl handshake error:", err )
 224                                                                 self.fatalerror = err
 225                                                         end
 226                                                 end
 227                                                 if self.fatalerror then
 228                                                         if call_onconnect then
 229                                                                 self.ondisconnect = nil  -- dont call this when client isnt really connected
 230                                                         end
 231                                                         self:_close()
 232                                                         debug( "handshake failed because:", self.fatalerror )
 233                                                         self.eventhandshake = nil
 234                                                         return -1
 235                                                 end
 236                                                 event = coroutine_yield( event, cfg.HANDSHAKE_TIMEOUT )  -- yield this monster...
 237                                         end
 238                                 end
 239                         )
 240                         debug "starting handshake..."
 241                         self:_lock( false, true, true )  -- unlock read/write events, but keep interface locked
 242                         self.eventhandshake = addevent( base, self.conn, EV_READWRITE, handshakecallback, cfg.HANDSHAKE_TIMEOUT )
 243                         return true
 244         end
 245         function interface_mt:_destroy()  -- close this interface + events and call last listener
 246                         debug( "closing client with id:", self.id, self.fatalerror )
 247                         self:_lock( true, true, true )  -- first of all, lock the interface to avoid further actions
 248                         local _
 249                         _ = self.eventread and self.eventread:close( )
 250                         if self.type == "client" then
 251                                 _ = self.eventwrite and self.eventwrite:close( )
 252                                 _ = self.eventhandshake and self.eventhandshake:close( )
 253                                 _ = self.eventstarthandshake and self.eventstarthandshake:close( )
 254                                 _ = self.eventconnect and self.eventconnect:close( )
 255                                 _ = self.eventsession and self.eventsession:close( )
 256                                 _ = self.eventwritetimeout and self.eventwritetimeout:close( )
 257                                 _ = self.eventreadtimeout and self.eventreadtimeout:close( )
 258                                 _ = self.ondisconnect and self:ondisconnect( self.fatalerror ~= "client to close" and self.fatalerror)  -- call ondisconnect listener (wont be the case if handshake failed on connect)
 259                                 _ = self.conn and self.conn:close( ) -- close connection
 260                                 _ = self._server and self._server:counter(-1);
 261                                 self.eventread, self.eventwrite = nil, nil
 262                                 self.eventstarthandshake, self.eventhandshake, self.eventclose = nil, nil, nil
 263                                 self.readcallback, self.writecallback = nil, nil
 264                         else
 265                                 self.conn:close( )
 266                                 self.eventread, self.eventclose = nil, nil
 267                                 self.interface, self.readcallback = nil, nil
 268                         end
 269                         interfacelist( "delete", self )
 270                         return true
 271         end
 272
 273         function interface_mt:_lock(nointerface, noreading, nowriting)  -- lock or unlock this interface or events
 274                         self.nointerface, self.noreading, self.nowriting = nointerface, noreading, nowriting
 275                         return nointerface, noreading, nowriting
 276         end
 277
 278         --TODO: Deprecate
 279         function interface_mt:lock_read(switch)
 280                 if switch then
 281                         return self:pause();
 282                 else
 283                         return self:resume();
 284                 end
 285         end
 286
 287         function interface_mt:pause()
 288                 return self:_lock(self.nointerface, true, self.nowriting);
 289         end
 290
 291         function interface_mt:resume()
 292                 self:_lock(self.nointerface, false, self.nowriting);
 293                 if not self.eventread then
 294                         self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
 295                 end
 296         end
 297
 298         function interface_mt:counter(c)
 299                 if c then
 300                         self._connections = self._connections + c
 301                 end
 302                 return self._connections
 303         end
 304
 305         -- Public methods
 306         function interface_mt:write(data)
 307                 if self.nowriting then return nil, "locked" end
 308                 --vdebug( "try to send data to client, id/data:", self.id, data )
 309                 data = tostring( data )
 310                 local len = #data
 311                 local total = len + self.writebufferlen
 312                 if total > cfg.MAX_SEND_LENGTH then  -- check buffer length
 313                         local err = "send buffer exceeded"
 314                         debug( "error:", err )  -- to much, check your app
 315                         return nil, err
 316                 end
 317                 t_insert(self.writebuffer, data) -- new buffer
 318                 self.writebufferlen = total
 319                 if not self.eventwrite then  -- register new write event
 320                         --vdebug( "register new write event" )
 321                         self.eventwrite = addevent( base, self.conn, EV_WRITE, self.writecallback, cfg.WRITE_TIMEOUT )
 322                 end
 323                 return true
 324         end
 325         function interface_mt:close()
 326                 if self.nointerface then return nil, "locked"; end
 327                 debug( "try to close client connection with id:", self.id )
 328                 if self.type == "client" then
 329                         self.fatalerror = "client to close"
 330                         if self.eventwrite then -- wait for incomplete write request
 331                                 self:_lock( true, true, false )
 332                                 debug "closing delayed until writebuffer is empty"
 333                                 return nil, "writebuffer not empty, waiting"
 334                         else -- close now
 335                                 self:_lock( true, true, true )
 336                                 self:_close()
 337                                 return true
 338                         end
 339                 else
 340                         debug( "try to close server with id:", tostring(self.id))
 341                         self.fatalerror = "server to close"
 342                         self:_lock( true )
 343                         self:_close( 0 )
 344                         return true
 345                 end
 346         end
 347
 348         function interface_mt:socket()
 349                 return self.conn
 350         end
 351
 352         function interface_mt:server()
 353                 return self._server or self;
 354         end
 355
 356         function interface_mt:port()
 357                 return self._port
 358         end
 359
 360         function interface_mt:serverport()
 361                 return self._serverport
 362         end
 363
 364         function interface_mt:ip()
 365                 return self._ip
 366         end
 367
 368         function interface_mt:ssl()
 369                 return self._usingssl
 370         end
 371         interface_mt.clientport = interface_mt.port -- COMPAT server_select
 372
 373         function interface_mt:type()
 374                 return self._type or "client"
 375         end
 376
 377         function interface_mt:connections()
 378                 return self._connections
 379         end
 380
 381         function interface_mt:address()
 382                 return self.addr
 383         end
 384
 385         function interface_mt:set_sslctx(sslctx)
 386                 self._sslctx = sslctx;
 387                 if sslctx then
 388                         self.starttls = nil; -- use starttls() of interface_mt
 389                 else
 390                         self.starttls = false; -- prevent starttls()
 391                 end
 392         end
 393
 394         function interface_mt:set_mode(pattern)
 395                 if pattern then
 396                         self._pattern = pattern;
 397                 end
 398                 return self._pattern;
 399         end
 400
 401         function interface_mt:set_send(new_send)
 402                 -- No-op, we always use the underlying connection's send
 403         end
 404
 405         function interface_mt:starttls(sslctx, call_onconnect)
 406                 debug( "try to start ssl at client id:", self.id )
 407                 local err
 408                 self._sslctx = sslctx;
 409                 if self._usingssl then  -- startssl was already called
 410                         err = "ssl already active"
 411                 end
 412                 if err then
 413                         debug( "error:", err )
 414                         return nil, err
 415                 end
 416                 self._usingssl = true
 417                 self.startsslcallback = function( )  -- we have to start the handshake outside of a read/write event
 418                         self.startsslcallback = nil
 419                         self:_start_ssl(call_onconnect);
 420                         self.eventstarthandshake = nil
 421                         return -1
 422                 end
 423                 if not self.eventwrite then
 424                         self:_lock( true, true, true )  -- lock the interface, to not disturb the handshake
 425                         self.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, self.startsslcallback, 0 )  -- add event to start handshake
 426                 else  -- wait until writebuffer is empty
 427                         self:_lock( true, true, false )
 428                         debug "ssl session delayed until writebuffer is empty..."
 429                 end
 430                 self.starttls = false;
 431                 return true
 432         end
 433
 434         function interface_mt:setoption(option, value)
 435                 if self.conn.setoption then
 436                         return self.conn:setoption(option, value);
 437                 end
 438                 return false, "setoption not implemented";
 439         end
 440
 441         function interface_mt:setlistener(listener)
 442                 self:ondetach(); -- Notify listener that it is no longer responsible for this connection
 443                 self.onconnect, self.ondisconnect, self.onincoming, self.ontimeout,
 444                 self.onreadtimeout, self.onstatus, self.ondetach
 445                         = listener.onconnect, listener.ondisconnect, listener.onincoming, listener.ontimeout,
 446                           listener.onreadtimeout, listener.onstatus, listener.ondetach;
 447         end
 448
 449         -- Stub handlers
 450         function interface_mt:onconnect()
 451         end
 452         function interface_mt:onincoming()
 453         end
 454         function interface_mt:ondisconnect()
 455         end
 456         function interface_mt:ontimeout()
 457         end
 458         function interface_mt:onreadtimeout()
 459                 self.fatalerror = "timeout during receiving"
 460                 debug( "connection failed:", self.fatalerror )
 461                 self:_close()
 462                 self.eventread = nil
 463         end
 464         function interface_mt:ondrain()
 465         end
 466         function interface_mt:ondetach()
 467         end
 468         function interface_mt:onstatus()
 469         end
 470 end
 471
 472 -- End of client interface methods
 473
 474 local handleclient;
 475 do
 476         local string_sub = string.sub  -- caching table lookups
 477         local addevent = base.addevent
 478         local socket_gettime = socket.gettime
 479         function handleclient( client, ip, port, server, pattern, listener, sslctx )  -- creates an client interface
 480                 --vdebug("creating client interfacce...")
 481                 local interface = {
 482                         type = "client";
 483                         conn = client;
 484                         currenttime = socket_gettime( );  -- safe the origin
 485                         writebuffer = {};  -- writebuffer
 486                         writebufferlen = 0;  -- length of writebuffer
 487                         send = client.send;  -- caching table lookups
 488                         receive = client.receive;
 489                         onconnect = listener.onconnect;  -- will be called when client disconnects
 490                         ondisconnect = listener.ondisconnect;  -- will be called when client disconnects
 491                         onincoming = listener.onincoming;  -- will be called when client sends data
 492                         ontimeout = listener.ontimeout; -- called when fatal socket timeout occurs
 493                         onreadtimeout = listener.onreadtimeout; -- called when socket inactivity timeout occurs
 494                         ondrain = listener.ondrain; -- called when writebuffer is empty
 495                         ondetach = listener.ondetach; -- called when disassociating this listener from this connection
 496                         onstatus = listener.onstatus; -- called for status changes (e.g. of SSL/TLS)
 497                         eventread = false, eventwrite = false, eventclose = false,
 498                         eventhandshake = false, eventstarthandshake = false;  -- event handler
 499                         eventconnect = false, eventsession = false;  -- more event handler...
 500                         eventwritetimeout = false;  -- even more event handler...
 501                         eventreadtimeout = false;
 502                         fatalerror = false;  -- error message
 503                         writecallback = false;  -- will be called on write events
 504                         readcallback = false;  -- will be called on read events
 505                         nointerface = true;  -- lock/unlock parameter of this interface
 506                         noreading = false, nowriting = false;  -- locks of the read/writecallback
 507                         startsslcallback = false;  -- starting handshake callback
 508                         position = false;  -- position of client in interfacelist
 509
 510                         -- Properties
 511                         _ip = ip, _port = port, _server = server, _pattern = pattern,
 512                         _serverport = (server and server:port() or nil),
 513                         _sslctx = sslctx; -- parameters
 514                         _usingssl = false;  -- client is using ssl;
 515                 }
 516                 if not has_luasec then interface.starttls = false; end
 517                 interface.id = tostring(interface):match("%x+$");
 518                 interface.writecallback = function( event )  -- called on write events
 519                         --vdebug( "new client write event, id/ip/port:", interface, ip, port )
 520                         if interface.nowriting or ( interface.fatalerror and ( "client to close" ~= interface.fatalerror ) ) then  -- leave this event
 521                                 --vdebug( "leaving this event because:", interface.nowriting or interface.fatalerror )
 522                                 interface.eventwrite = false
 523                                 return -1
 524                         end
 525                         if EV_TIMEOUT == event then  -- took too long to write some data to socket -> disconnect
 526                                 interface.fatalerror = "timeout during writing"
 527                                 debug( "writing failed:", interface.fatalerror )
 528                                 interface:_close()
 529                                 interface.eventwrite = false
 530                                 return -1
 531                         else  -- can write :)
 532                                 if interface._usingssl then  -- handle luasec
 533                                         if interface.eventreadtimeout then  -- we have to read first
 534                                                 local ret = interface.readcallback( )  -- call readcallback
 535                                                 --vdebug( "tried to read in writecallback, result:", ret )
 536                                         end
 537                                         if interface.eventwritetimeout then  -- luasec only
 538                                                 interface.eventwritetimeout:close( )  -- first we have to close timeout event which where regged after a wantread error
 539                                                 interface.eventwritetimeout = false
 540                                         end
 541                                 end
 542                                 interface.writebuffer = { t_concat(interface.writebuffer) }
 543                                 local succ, err, byte = interface.conn:send( interface.writebuffer[1], 1, interface.writebufferlen )
 544                                 --vdebug( "write data:", interface.writebuffer, "error:", err, "part:", byte )
 545                                 if succ then  -- writing succesful
 546                                         interface.writebuffer[1] = nil
 547                                         interface.writebufferlen = 0
 548                                         interface:ondrain();
 549                                         if interface.fatalerror then
 550                                                 debug "closing client after writing"
 551                                                 interface:_close()  -- close interface if needed
 552                                         elseif interface.startsslcallback then  -- start ssl connection if needed
 553                                                 debug "starting ssl handshake after writing"
 554                                                 interface.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, interface.startsslcallback, 0 )
 555                                         elseif interface.eventreadtimeout then
 556                                                 return EV_WRITE, EV_TIMEOUT
 557                                         end
 558                                         interface.eventwrite = nil
 559                                         return -1
 560                                 elseif byte and (err == "timeout" or err == "wantwrite") then  -- want write again
 561                                         --vdebug( "writebuffer is not empty:", err )
 562                                         interface.writebuffer[1] = string_sub( interface.writebuffer[1], byte + 1, interface.writebufferlen )  -- new buffer
 563                                         interface.writebufferlen = interface.writebufferlen - byte
 564                                         if "wantread" == err then  -- happens only with luasec
 565                                                 local callback = function( )
 566                                                         interface:_close()
 567                                                         interface.eventwritetimeout = nil
 568                                                         return -1;
 569                                                 end
 570                                                 interface.eventwritetimeout = addevent( base, nil, EV_TIMEOUT, callback, cfg.WRITE_TIMEOUT )  -- reg a new timeout event
 571                                                 debug( "wantread during write attempt, reg it in readcallback but dont know what really happens next..." )
 572                                                 -- hopefully this works with luasec; its simply not possible to use 2 different write events on a socket in luaevent
 573                                                 return -1
 574                                         end
 575                                         return EV_WRITE, cfg.WRITE_TIMEOUT
 576                                 else  -- connection was closed during writing or fatal error
 577                                         interface.fatalerror = err or "fatal error"
 578                                         debug( "connection failed in write event:", interface.fatalerror )
 579                                         interface:_close()
 580                                         interface.eventwrite = nil
 581                                         return -1
 582                                 end
 583                         end
 584                 end
 585
 586                 interface.readcallback = function( event )  -- called on read events
 587                         --vdebug( "new client read event, id/ip/port:", tostring(interface.id), tostring(ip), tostring(port) )
 588                         if interface.noreading or interface.fatalerror then  -- leave this event
 589                                 --vdebug( "leaving this event because:", tostring(interface.noreading or interface.fatalerror) )
 590                                 interface.eventread = nil
 591                                 return -1
 592                         end
 593                         if EV_TIMEOUT == event and interface:onreadtimeout() ~= true then
 594                                 return -1 -- took too long to get some data from client -> disconnect
 595                         end
 596                         if interface._usingssl then  -- handle luasec
 597                                 if interface.eventwritetimeout then  -- ok, in the past writecallback was regged
 598                                         local ret = interface.writecallback( )  -- call it
 599                                         --vdebug( "tried to write in readcallback, result:", tostring(ret) )
 600                                 end
 601                                 if interface.eventreadtimeout then
 602                                         interface.eventreadtimeout:close( )
 603                                         interface.eventreadtimeout = nil
 604                                 end
 605                         end
 606                         local buffer, err, part = interface.conn:receive( interface._pattern )  -- receive buffer with "pattern"
 607                         --vdebug( "read data:", tostring(buffer), "error:", tostring(err), "part:", tostring(part) )
 608                         buffer = buffer or part
 609                         if buffer and #buffer > cfg.MAX_READ_LENGTH then  -- check buffer length
 610                                 interface.fatalerror = "receive buffer exceeded"
 611                                 debug( "fatal error:", interface.fatalerror )
 612                                 interface:_close()
 613                                 interface.eventread = nil
 614                                 return -1
 615                         end
 616                         if err and ( err ~= "timeout" and err ~= "wantread" ) then
 617                                 if "wantwrite" == err then -- need to read on write event
 618                                         if not interface.eventwrite then  -- register new write event if needed
 619                                                 interface.eventwrite = addevent( base, interface.conn, EV_WRITE, interface.writecallback, cfg.WRITE_TIMEOUT )
 620                                         end
 621                                         interface.eventreadtimeout = addevent( base, nil, EV_TIMEOUT,
 622                                                 function( )
 623                                                         interface:_close()
 624                                                 end, cfg.READ_TIMEOUT
 625                                         )
 626                                         debug( "wantwrite during read attempt, reg it in writecallback but dont know what really happens next..." )
 627                                         -- to be honest i dont know what happens next, if it is allowed to first read, the write etc...
 628                                 else  -- connection was closed or fatal error
 629                                         interface.fatalerror = err
 630                                         debug( "connection failed in read event:", interface.fatalerror )
 631                                         interface:_close()
 632                                         interface.eventread = nil
 633                                         return -1
 634                                 end
 635                         else
 636                                 interface.onincoming( interface, buffer, err )  -- send new data to listener
 637                         end
 638                         if interface.noreading then
 639                                 interface.eventread = nil;
 640                                 return -1;
 641                         end
 642                         return EV_READ, cfg.READ_TIMEOUT
 643                 end
 644
 645                 client:settimeout( 0 )  -- set non blocking
 646                 setmetatable(interface, interface_mt)
 647                 interfacelist( "add", interface )  -- add to interfacelist
 648                 return interface
 649         end
 650 end
 651
 652 local handleserver
 653 do
 654         function handleserver( server, addr, port, pattern, listener, sslctx )  -- creates an server interface
 655                 debug "creating server interface..."
 656                 local interface = {
 657                         _connections = 0;
 658
 659                         conn = server;
 660                         onconnect = listener.onconnect;  -- will be called when new client connected
 661                         eventread = false;  -- read event handler
 662                         eventclose = false; -- close event handler
 663                         readcallback = false; -- read event callback
 664                         fatalerror = false; -- error message
 665                         nointerface = true;  -- lock/unlock parameter
 666
 667                         _ip = addr, _port = port, _pattern = pattern,
 668                         _sslctx = sslctx;
 669                 }
 670                 interface.id = tostring(interface):match("%x+$");
 671                 interface.readcallback = function( event )  -- server handler, called on incoming connections
 672                         --vdebug( "server can accept, id/addr/port:", interface, addr, port )
 673                         if interface.fatalerror then
 674                                 --vdebug( "leaving this event because:", self.fatalerror )
 675                                 interface.eventread = nil
 676                                 return -1
 677                         end
 678                         local delay = cfg.ACCEPT_DELAY
 679                         if EV_TIMEOUT == event then
 680                                 if interface._connections >= cfg.MAX_CONNECTIONS then  -- check connection count
 681                                         debug( "to many connections, seconds to wait for next accept:", delay )
 682                                         return EV_TIMEOUT, delay  -- timeout...
 683                                 else
 684                                         return EV_READ  -- accept again
 685                                 end
 686                         end
 687                         --vdebug("max connection check ok, accepting...")
 688                         local client, err = server:accept()    -- try to accept; TODO: check err
 689                         while client do
 690                                 if interface._connections >= cfg.MAX_CONNECTIONS then
 691                                         client:close( )  -- refuse connection
 692                                         debug( "maximal connections reached, refuse client connection; accept delay:", delay )
 693                                         return EV_TIMEOUT, delay  -- delay for next accept attempt
 694                                 end
 695                                 local client_ip, client_port = client:getpeername( )
 696                                 interface._connections = interface._connections + 1  -- increase connection count
 697                                 local clientinterface = handleclient( client, client_ip, client_port, interface, pattern, listener, sslctx )
 698                                 --vdebug( "client id:", clientinterface, "startssl:", startssl )
 699                                 if has_luasec and sslctx then
 700                                         clientinterface:starttls(sslctx, true)
 701                                 else
 702                                         clientinterface:_start_session( true )
 703                                 end
 704                                 debug( "accepted incoming client connection from:", client_ip or "<unknown IP>", client_port or "<unknown port>", "to", port or "<unknown port>");
 705
 706                                 client, err = server:accept()    -- try to accept again
 707                         end
 708                         return EV_READ
 709                 end
 710
 711                 server:settimeout( 0 )
 712                 setmetatable(interface, interface_mt)
 713                 interfacelist( "add", interface )
 714                 interface:_start_session()
 715                 return interface
 716         end
 717 end
 718
 719 local addserver = ( function( )
 720         return function( addr, port, listener, pattern, sslctx, startssl )  -- TODO: check arguments
 721                 --vdebug( "creating new tcp server with following parameters:", addr or "nil", port or "nil", sslctx or "nil", startssl or "nil")
 722                 if sslctx and not has_luasec then
 723                         debug "fatal error: luasec not found"
 724                         return nil, "luasec not found"
 725                 end
 726                 local server, err = socket.bind( addr, port, cfg.ACCEPT_QUEUE )  -- create server socket
 727                 if not server then
 728                         debug( "creating server socket on "..addr.." port "..port.." failed:", err )
 729                         return nil, err
 730                 end
 731                 local interface = handleserver( server, addr, port, pattern, listener, sslctx, startssl )  -- new server handler
 732                 debug( "new server created with id:", tostring(interface))
 733                 return interface
 734         end
 735 end )( )
 736
 737 local addclient, wrapclient
 738 do
 739         function wrapclient( client, ip, port, listeners, pattern, sslctx )
 740                 local interface = handleclient( client, ip, port, nil, pattern, listeners, sslctx )
 741                 interface:_start_connection(sslctx)
 742                 return interface, client
 743                 --function handleclient( client, ip, port, server, pattern, listener, _, sslctx )  -- creates an client interface
 744         end
 745
 746         function addclient( addr, serverport, listener, pattern, sslctx, typ )
 747                 if sslctx and not has_luasec then
 748                         debug "need luasec, but not available"
 749                         return nil, "luasec not found"
 750                 end
 751                 if not typ then
 752                         local addrinfo, err = getaddrinfo(addr)
 753                         if not addrinfo then return nil, err end
 754                         if addrinfo[1] and addrinfo[1].family == "inet6" then
 755                                 typ = "tcp6"
 756                         else
 757                                 typ = "tcp"
 758                         end
 759                 end
 760                 local create = socket[typ]
 761                 if type( create ) ~= "function"  then
 762                         return nil, "invalid socket type"
 763                 end
 764                 local client, err = create()  -- creating new socket
 765                 if not client then
 766                         debug( "cannot create socket:", err )
 767                         return nil, err
 768                 end
 769                 client:settimeout( 0 )  -- set nonblocking
 770                 local res, err = client:connect( addr, serverport )  -- connect
 771                 if res or ( err == "timeout" ) then
 772                         local ip, port = client:getsockname( )
 773                         local interface = wrapclient( client, ip, serverport, listener, pattern, sslctx )
 774                         interface:_start_connection( startssl )
 775                         debug( "new connection id:", interface.id )
 776                         return interface, err
 777                 else
 778                         debug( "new connection failed:", err )
 779                         return nil, err
 780                 end
 781         end
 782 end
 783
 784
 785 local loop = function( )  -- starts the event loop
 786         base:loop( )
 787         return "quitting";
 788 end
 789
 790 local newevent = ( function( )
 791         local add = base.addevent
 792         return function( ... )
 793                 return add( base, ... )
 794         end
 795 end )( )
 796
 797 local closeallservers = function( arg )
 798         for _, item in ipairs( interfacelist( ) ) do
 799                 if item.type == "server" then
 800                         item:close( arg )
 801                 end
 802         end
 803 end
 804
 805 local function setquitting(yes)
 806         if yes then
 807                  -- Quit now
 808                  closeallservers();
 809                  base:loopexit();
 810         end
 811 end
 812
 813 local function get_backend()
 814         return base:method();
 815 end
 816
 817 -- We need to hold onto the events to stop them
 818 -- being garbage-collected
 819 local signal_events = {}; -- [signal_num] -> event object
 820 local function hook_signal(signal_num, handler)
 821         local function _handler(event)
 822                 local ret = handler();
 823                 if ret ~= false then -- Continue handling this signal?
 824                         return EV_SIGNAL; -- Yes
 825                 end
 826                 return -1; -- Close this event
 827         end
 828         signal_events[signal_num] = base:addevent(signal_num, EV_SIGNAL, _handler);
 829         return signal_events[signal_num];
 830 end
 831
 832 local function link(sender, receiver, buffersize)
 833         local sender_locked;
 834
 835         function receiver:ondrain()
 836                 if sender_locked then
 837                         sender:resume();
 838                         sender_locked = nil;
 839                 end
 840         end
 841
 842         function sender:onincoming(data)
 843                 receiver:write(data);
 844                 if receiver.writebufferlen >= buffersize then
 845                         sender_locked = true;
 846                         sender:pause();
 847                 end
 848         end
 849         sender:set_mode("*a");
 850 end
 851
 852 return {
 853
 854         cfg = cfg,
 855         base = base,
 856         loop = loop,
 857         link = link,
 858         event = event,
 859         event_base = base,
 860         addevent = newevent,
 861         addserver = addserver,
 862         addclient = addclient,
 863         wrapclient = wrapclient,
 864         setquitting = setquitting,
 865         closeall = closeallservers,
 866         get_backend = get_backend,
 867         hook_signal = hook_signal,
 868
 869         __NAME = SCRIPT_NAME,
 870         __DATE = LAST_MODIFIED,
 871         __AUTHOR = SCRIPT_AUTHOR,
 872         __VERSION = SCRIPT_VERSION,
 873
 874 }