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 -- luacheck: ignore 212/self 431/err 211/ret
  15
  16 local SCRIPT_NAME           = "server_event.lua"
  17 local SCRIPT_VERSION        = "0.05"
  18 local SCRIPT_AUTHOR         = "blastbeat"
  19 local LAST_MODIFIED         = "2009/11/20"
  20
  21 local cfg = {
  22         MAX_CONNECTIONS       = 100000,  -- max per server connections (use "ulimit -n" on *nix)
  23         MAX_HANDSHAKE_ATTEMPTS= 1000,  -- attempts to finish ssl handshake
  24         HANDSHAKE_TIMEOUT     = 60,  -- timeout in seconds per handshake attempt
  25         MAX_READ_LENGTH       = 1024 * 1024 * 1024 * 1024,  -- max bytes allowed to read from sockets
  26         MAX_SEND_LENGTH       = 1024 * 1024 * 1024 * 1024,  -- max bytes size of write buffer (for writing on sockets)
  27         ACCEPT_QUEUE          = 128,  -- might influence the length of the pending sockets queue
  28         ACCEPT_DELAY          = 10,  -- seconds to wait until the next attempt of a full server to accept
  29         READ_TIMEOUT          = 60 * 60 * 6,  -- timeout in seconds for read data from socket
  30         WRITE_TIMEOUT         = 180,  -- timeout in seconds for write data on socket
  31         CONNECT_TIMEOUT       = 20,  -- timeout in seconds for connection attempts
  32         CLEAR_DELAY           = 5,  -- seconds to wait for clearing interface list (and calling ondisconnect listeners)
  33         READ_RETRY_DELAY      = 1e-06, -- if, after reading, there is still data in buffer, wait this long and continue reading
  34         DEBUG                 = true,  -- show debug messages
  35 }
  36
  37 local pairs = pairs
  38 local select = select
  39 local require = require
  40 local tostring = tostring
  41 local setmetatable = setmetatable
  42
  43 local t_insert = table.insert
  44 local t_concat = table.concat
  45 local s_sub = string.sub
  46
  47 local coroutine_wrap = coroutine.wrap
  48 local coroutine_yield = coroutine.yield
  49
  50 local has_luasec, ssl = pcall ( require , "ssl" )
  51 local socket = require "socket"
  52 local levent = require "luaevent.core"
  53
  54 local socket_gettime = socket.gettime
  55 local getaddrinfo = socket.dns.getaddrinfo
  56
  57 local log = require ("util.logger").init("socket")
  58
  59 local function debug(...)
  60         return log("debug", ("%s "):rep(select('#', ...)), ...)
  61 end
  62 -- local vdebug = debug;
  63
  64 local bitor = ( function( ) -- thx Rici Lake
  65         local hasbit = function( x, p )
  66                 return x % ( p + p ) >= p
  67         end
  68         return function( x, y )
  69                 local p = 1
  70                 local z = 0
  71                 local limit = x > y and x or y
  72                 while p <= limit do
  73                         if hasbit( x, p ) or hasbit( y, p ) then
  74                                 z = z + p
  75                         end
  76                         p = p + p
  77                 end
  78                 return z
  79         end
  80 end )( )
  81
  82 local base = levent.new( )
  83 local addevent = base.addevent
  84 local EV_READ = levent.EV_READ
  85 local EV_WRITE = levent.EV_WRITE
  86 local EV_TIMEOUT = levent.EV_TIMEOUT
  87 local EV_SIGNAL = levent.EV_SIGNAL
  88
  89 local EV_READWRITE = bitor( EV_READ, EV_WRITE )
  90
  91 local interfacelist = { }
  92
  93 -- Client interface methods
  94 local interface_mt = {}; interface_mt.__index = interface_mt;
  95
  96 -- Private methods
  97 function interface_mt:_close()
  98         return self:_destroy();
  99 end
 100
 101 function interface_mt:_start_connection(plainssl) -- called from wrapclient
 102         local callback = function( event )
 103                 if EV_TIMEOUT == event then  -- timeout during connection
 104                         self.fatalerror = "connection timeout"
 105                         self:ontimeout()  -- call timeout listener
 106                         self:_close()
 107                         debug( "new connection failed. id:", self.id, "error:", self.fatalerror )
 108                 else
 109                         if plainssl and has_luasec then  -- start ssl session
 110                                 self:starttls(self._sslctx, true)
 111                         else  -- normal connection
 112                                 self:_start_session(true)
 113                         end
 114                         debug( "new connection established. id:", self.id )
 115                 end
 116                 self.eventconnect = nil
 117                 return -1
 118         end
 119         self.eventconnect = addevent( base, self.conn, EV_WRITE, callback, cfg.CONNECT_TIMEOUT )
 120         return true
 121 end
 122 function interface_mt:_start_session(call_onconnect) -- new session, for example after startssl
 123         if self.type == "client" then
 124                 local callback = function( )
 125                         self:_lock( false,  false, false )
 126                         --vdebug( "start listening on client socket with id:", self.id )
 127                         self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
 128                         if call_onconnect then
 129                                 self:onconnect()
 130                         end
 131                         self.eventsession = nil
 132                         return -1
 133                 end
 134                 self.eventsession = addevent( base, nil, EV_TIMEOUT, callback, 0 )
 135         else
 136                 self:_lock( false )
 137                 --vdebug( "start listening on server socket with id:", self.id )
 138                 self.eventread = addevent( base, self.conn, EV_READ, self.readcallback )  -- register callback
 139         end
 140         return true
 141 end
 142 function interface_mt:_start_ssl(call_onconnect) -- old socket will be destroyed, therefore we have to close read/write events first
 143         --vdebug( "starting ssl session with client id:", self.id )
 144         local _
 145         _ = self.eventread and self.eventread:close( )  -- close events; this must be called outside of the event callbacks!
 146         _ = self.eventwrite and self.eventwrite:close( )
 147         self.eventread, self.eventwrite = nil, nil
 148         local err
 149         self.conn, err = ssl.wrap( self.conn, self._sslctx )
 150         if err then
 151                 self.fatalerror = err
 152                 self.conn = nil  -- cannot be used anymore
 153                 if call_onconnect then
 154                         self.ondisconnect = nil  -- dont call this when client isnt really connected
 155                 end
 156                 self:_close()
 157                 debug( "fatal error while ssl wrapping:", err )
 158                 return false
 159         end
 160         self.conn:settimeout( 0 )  -- set non blocking
 161         local handshakecallback = coroutine_wrap(function( event )
 162                 local _, err
 163                 local attempt = 0
 164                 local maxattempt = cfg.MAX_HANDSHAKE_ATTEMPTS
 165                 while attempt < maxattempt do  -- no endless loop
 166                         attempt = attempt + 1
 167                         debug( "ssl handshake of client with id:"..tostring(self)..", attempt:"..attempt )
 168                         if attempt > maxattempt then
 169                                 self.fatalerror = "max handshake attempts exceeded"
 170                         elseif EV_TIMEOUT == event then
 171                                 self.fatalerror = "timeout during handshake"
 172                         else
 173                                 _, err = self.conn:dohandshake( )
 174                                 if not err then
 175                                         self:_lock( false, false, false )  -- unlock the interface; sending, closing etc allowed
 176                                         self.send = self.conn.send  -- caching table lookups with new client object
 177                                         self.receive = self.conn.receive
 178                                         if not call_onconnect then  -- trigger listener
 179                                                 self:onstatus("ssl-handshake-complete");
 180                                         end
 181                                         self:_start_session( call_onconnect )
 182                                         debug( "ssl handshake done" )
 183                                         self.eventhandshake = nil
 184                                         return -1
 185                                 end
 186                                 if err == "wantwrite" then
 187                                         event = EV_WRITE
 188                                 elseif err == "wantread" then
 189                                         event = EV_READ
 190                                 else
 191                                         debug( "ssl handshake error:", err )
 192                                         self.fatalerror = err
 193                                 end
 194                         end
 195                         if self.fatalerror then
 196                                 if call_onconnect then
 197                                         self.ondisconnect = nil  -- dont call this when client isnt really connected
 198                                 end
 199                                 self:_close()
 200                                 debug( "handshake failed because:", self.fatalerror )
 201                                 self.eventhandshake = nil
 202                                 return -1
 203                         end
 204                         event = coroutine_yield( event, cfg.HANDSHAKE_TIMEOUT )  -- yield this monster...
 205                 end
 206         end
 207         )
 208         debug "starting handshake..."
 209         self:_lock( false, true, true )  -- unlock read/write events, but keep interface locked
 210         self.eventhandshake = addevent( base, self.conn, EV_READWRITE, handshakecallback, cfg.HANDSHAKE_TIMEOUT )
 211         return true
 212 end
 213 function interface_mt:_destroy()  -- close this interface + events and call last listener
 214         debug( "closing client with id:", self.id, self.fatalerror )
 215         self:_lock( true, true, true )  -- first of all, lock the interface to avoid further actions
 216         local _
 217         _ = self.eventread and self.eventread:close( )
 218         if self.type == "client" then
 219                 _ = self.eventwrite and self.eventwrite:close( )
 220                 _ = self.eventhandshake and self.eventhandshake:close( )
 221                 _ = self.eventstarthandshake and self.eventstarthandshake:close( )
 222                 _ = self.eventconnect and self.eventconnect:close( )
 223                 _ = self.eventsession and self.eventsession:close( )
 224                 _ = self.eventwritetimeout and self.eventwritetimeout:close( )
 225                 _ = self.eventreadtimeout and self.eventreadtimeout:close( )
 226                 _ = 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)
 227                 _ = self.conn and self.conn:close( ) -- close connection
 228                 _ = self._server and self._server:counter(-1);
 229                 self.eventread, self.eventwrite = nil, nil
 230                 self.eventstarthandshake, self.eventhandshake, self.eventclose = nil, nil, nil
 231                 self.readcallback, self.writecallback = nil, nil
 232         else
 233                 self.conn:close( )
 234                 self.eventread, self.eventclose = nil, nil
 235                 self.interface, self.readcallback = nil, nil
 236         end
 237         interfacelist[ self ] = nil
 238         return true
 239 end
 240
 241 function interface_mt:_lock(nointerface, noreading, nowriting)  -- lock or unlock this interface or events
 242         self.nointerface, self.noreading, self.nowriting = nointerface, noreading, nowriting
 243         return nointerface, noreading, nowriting
 244 end
 245
 246 --TODO: Deprecate
 247 function interface_mt:lock_read(switch)
 248         if switch then
 249                 return self:pause();
 250         else
 251                 return self:resume();
 252         end
 253 end
 254
 255 function interface_mt:pause()
 256         return self:_lock(self.nointerface, true, self.nowriting);
 257 end
 258
 259 function interface_mt:resume()
 260         self:_lock(self.nointerface, false, self.nowriting);
 261         if self.readcallback and not self.eventread then
 262                 self.eventread = addevent( base, self.conn, EV_READ, self.readcallback, cfg.READ_TIMEOUT );  -- register callback
 263                 return true;
 264         end
 265 end
 266
 267 function interface_mt:counter(c)
 268         if c then
 269                 self._connections = self._connections + c
 270         end
 271         return self._connections
 272 end
 273
 274 -- Public methods
 275 function interface_mt:write(data)
 276         if self.nowriting then return nil, "locked" end
 277         --vdebug( "try to send data to client, id/data:", self.id, data )
 278         data = tostring( data )
 279         local len = #data
 280         local total = len + self.writebufferlen
 281         if total > cfg.MAX_SEND_LENGTH then  -- check buffer length
 282                 local err = "send buffer exceeded"
 283                 debug( "error:", err )  -- to much, check your app
 284                 return nil, err
 285         end
 286         t_insert(self.writebuffer, data) -- new buffer
 287         self.writebufferlen = total
 288         if not self.eventwrite then  -- register new write event
 289                 --vdebug( "register new write event" )
 290                 self.eventwrite = addevent( base, self.conn, EV_WRITE, self.writecallback, cfg.WRITE_TIMEOUT )
 291         end
 292         return true
 293 end
 294 function interface_mt:close()
 295         if self.nointerface then return nil, "locked"; end
 296         debug( "try to close client connection with id:", self.id )
 297         if self.type == "client" then
 298                 self.fatalerror = "client to close"
 299                 if self.eventwrite then -- wait for incomplete write request
 300                         self:_lock( true, true, false )
 301                         debug "closing delayed until writebuffer is empty"
 302                         return nil, "writebuffer not empty, waiting"
 303                 else -- close now
 304                         self:_lock( true, true, true )
 305                         self:_close()
 306                         return true
 307                 end
 308         else
 309                 debug( "try to close server with id:", tostring(self.id))
 310                 self.fatalerror = "server to close"
 311                 self:_lock( true )
 312                 self:_close( 0 )
 313                 return true
 314         end
 315 end
 316
 317 function interface_mt:socket()
 318         return self.conn
 319 end
 320
 321 function interface_mt:server()
 322         return self._server or self;
 323 end
 324
 325 function interface_mt:port()
 326         return self._port
 327 end
 328
 329 function interface_mt:serverport()
 330         return self._serverport
 331 end
 332
 333 function interface_mt:ip()
 334         return self._ip
 335 end
 336
 337 function interface_mt:ssl()
 338         return self._usingssl
 339 end
 340 interface_mt.clientport = interface_mt.port -- COMPAT server_select
 341
 342 function interface_mt:type()
 343         return self._type or "client"
 344 end
 345
 346 function interface_mt:connections()
 347         return self._connections
 348 end
 349
 350 function interface_mt:address()
 351         return self.addr
 352 end
 353
 354 function interface_mt:set_sslctx(sslctx)
 355         self._sslctx = sslctx;
 356         if sslctx then
 357                 self.starttls = nil; -- use starttls() of interface_mt
 358         else
 359                 self.starttls = false; -- prevent starttls()
 360         end
 361 end
 362
 363 function interface_mt:set_mode(pattern)
 364         if pattern then
 365                 self._pattern = pattern;
 366         end
 367         return self._pattern;
 368 end
 369
 370 function interface_mt:set_send(new_send) -- luacheck: ignore 212
 371         -- No-op, we always use the underlying connection's send
 372 end
 373
 374 function interface_mt:starttls(sslctx, call_onconnect)
 375         debug( "try to start ssl at client id:", self.id )
 376         local err
 377         self._sslctx = sslctx;
 378         if self._usingssl then  -- startssl was already called
 379                 err = "ssl already active"
 380         end
 381         if err then
 382                 debug( "error:", err )
 383                 return nil, err
 384         end
 385         self._usingssl = true
 386         self.startsslcallback = function( )  -- we have to start the handshake outside of a read/write event
 387                 self.startsslcallback = nil
 388                 self:_start_ssl(call_onconnect);
 389                 self.eventstarthandshake = nil
 390                 return -1
 391         end
 392         if not self.eventwrite then
 393                 self:_lock( true, true, true )  -- lock the interface, to not disturb the handshake
 394                 self.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, self.startsslcallback, 0 )  -- add event to start handshake
 395         else
 396                 -- wait until writebuffer is empty
 397                 self:_lock( true, true, false )
 398                 debug "ssl session delayed until writebuffer is empty..."
 399         end
 400         self.starttls = false;
 401         return true
 402 end
 403
 404 function interface_mt:setoption(option, value)
 405         if self.conn.setoption then
 406                 return self.conn:setoption(option, value);
 407         end
 408         return false, "setoption not implemented";
 409 end
 410
 411 function interface_mt:setlistener(listener)
 412         self:ondetach(); -- Notify listener that it is no longer responsible for this connection
 413         self.onconnect = listener.onconnect;
 414         self.ondisconnect = listener.ondisconnect;
 415         self.onincoming = listener.onincoming;
 416         self.ontimeout = listener.ontimeout;
 417         self.onreadtimeout = listener.onreadtimeout;
 418         self.onstatus = listener.onstatus;
 419         self.ondetach = listener.ondetach;
 420 end
 421
 422 -- Stub handlers
 423 function interface_mt:onconnect()
 424 end
 425 function interface_mt:onincoming()
 426 end
 427 function interface_mt:ondisconnect()
 428 end
 429 function interface_mt:ontimeout()
 430 end
 431 function interface_mt:onreadtimeout()
 432         self.fatalerror = "timeout during receiving"
 433         debug( "connection failed:", self.fatalerror )
 434         self:_close()
 435         self.eventread = nil
 436 end
 437 function interface_mt:ondrain()
 438 end
 439 function interface_mt:ondetach()
 440 end
 441 function interface_mt:onstatus()
 442 end
 443
 444 -- End of client interface methods
 445
 446 local function handleclient( client, ip, port, server, pattern, listener, sslctx )  -- creates an client interface
 447         --vdebug("creating client interfacce...")
 448         local interface = {
 449                 type = "client";
 450                 conn = client;
 451                 currenttime = socket_gettime( );  -- safe the origin
 452                 writebuffer = {};  -- writebuffer
 453                 writebufferlen = 0;  -- length of writebuffer
 454                 send = client.send;  -- caching table lookups
 455                 receive = client.receive;
 456                 onconnect = listener.onconnect;  -- will be called when client disconnects
 457                 ondisconnect = listener.ondisconnect;  -- will be called when client disconnects
 458                 onincoming = listener.onincoming;  -- will be called when client sends data
 459                 ontimeout = listener.ontimeout; -- called when fatal socket timeout occurs
 460                 onreadtimeout = listener.onreadtimeout; -- called when socket inactivity timeout occurs
 461                 ondrain = listener.ondrain; -- called when writebuffer is empty
 462                 ondetach = listener.ondetach; -- called when disassociating this listener from this connection
 463                 onstatus = listener.onstatus; -- called for status changes (e.g. of SSL/TLS)
 464                 eventread = false, eventwrite = false, eventclose = false,
 465                 eventhandshake = false, eventstarthandshake = false;  -- event handler
 466                 eventconnect = false, eventsession = false;  -- more event handler...
 467                 eventwritetimeout = false;  -- even more event handler...
 468                 eventreadtimeout = false;
 469                 fatalerror = false;  -- error message
 470                 writecallback = false;  -- will be called on write events
 471                 readcallback = false;  -- will be called on read events
 472                 nointerface = true;  -- lock/unlock parameter of this interface
 473                 noreading = false, nowriting = false;  -- locks of the read/writecallback
 474                 startsslcallback = false;  -- starting handshake callback
 475                 position = false;  -- position of client in interfacelist
 476
 477                 -- Properties
 478                 _ip = ip, _port = port, _server = server, _pattern = pattern,
 479                 _serverport = (server and server:port() or nil),
 480                 _sslctx = sslctx; -- parameters
 481                 _usingssl = false;  -- client is using ssl;
 482         }
 483         if not has_luasec then interface.starttls = false; end
 484         interface.id = tostring(interface):match("%x+$");
 485         interface.writecallback = function( event )  -- called on write events
 486                 --vdebug( "new client write event, id/ip/port:", interface, ip, port )
 487                 if interface.nowriting or ( interface.fatalerror and ( "client to close" ~= interface.fatalerror ) ) then  -- leave this event
 488                         --vdebug( "leaving this event because:", interface.nowriting or interface.fatalerror )
 489                         interface.eventwrite = false
 490                         return -1
 491                 end
 492                 if EV_TIMEOUT == event then  -- took too long to write some data to socket -> disconnect
 493                         interface.fatalerror = "timeout during writing"
 494                         debug( "writing failed:", interface.fatalerror )
 495                         interface:_close()
 496                         interface.eventwrite = false
 497                         return -1
 498                 else  -- can write :)
 499                         if interface._usingssl then  -- handle luasec
 500                                 if interface.eventreadtimeout then  -- we have to read first
 501                                         local ret = interface.readcallback( )  -- call readcallback
 502                                         --vdebug( "tried to read in writecallback, result:", ret )
 503                                 end
 504                                 if interface.eventwritetimeout then  -- luasec only
 505                                         interface.eventwritetimeout:close( )  -- first we have to close timeout event which where regged after a wantread error
 506                                         interface.eventwritetimeout = false
 507                                 end
 508                         end
 509                         interface.writebuffer = { t_concat(interface.writebuffer) }
 510                         local succ, err, byte = interface.conn:send( interface.writebuffer[1], 1, interface.writebufferlen )
 511                         --vdebug( "write data:", interface.writebuffer, "error:", err, "part:", byte )
 512                         if succ then  -- writing succesful
 513                                 interface.writebuffer[1] = nil
 514                                 interface.writebufferlen = 0
 515                                 interface:ondrain();
 516                                 if interface.fatalerror then
 517                                         debug "closing client after writing"
 518                                         interface:_close()  -- close interface if needed
 519                                 elseif interface.startsslcallback then  -- start ssl connection if needed
 520                                         debug "starting ssl handshake after writing"
 521                                         interface.eventstarthandshake = addevent( base, nil, EV_TIMEOUT, interface.startsslcallback, 0 )
 522                                 elseif interface.writebufferlen ~= 0 then
 523                                         -- data possibly written from ondrain
 524                                         return EV_WRITE, cfg.WRITE_TIMEOUT
 525                                 elseif interface.eventreadtimeout then
 526                                         return EV_WRITE, cfg.WRITE_TIMEOUT
 527                                 end
 528                                 interface.eventwrite = nil
 529                                 return -1
 530                         elseif byte and (err == "timeout" or err == "wantwrite") then  -- want write again
 531                                 --vdebug( "writebuffer is not empty:", err )
 532                                 interface.writebuffer[1] = s_sub( interface.writebuffer[1], byte + 1, interface.writebufferlen )  -- new buffer
 533                                 interface.writebufferlen = interface.writebufferlen - byte
 534                                 if "wantread" == err then  -- happens only with luasec
 535                                         local callback = function( )
 536                                                 interface:_close()
 537                                                 interface.eventwritetimeout = nil
 538                                                 return -1;
 539                                         end
 540                                         interface.eventwritetimeout = addevent( base, nil, EV_TIMEOUT, callback, cfg.WRITE_TIMEOUT )  -- reg a new timeout event
 541                                         debug( "wantread during write attempt, reg it in readcallback but dont know what really happens next..." )
 542                                         -- hopefully this works with luasec; its simply not possible to use 2 different write events on a socket in luaevent
 543                                         return -1
 544                                 end
 545                                 return EV_WRITE, cfg.WRITE_TIMEOUT
 546                         else  -- connection was closed during writing or fatal error
 547                                 interface.fatalerror = err or "fatal error"
 548                                 debug( "connection failed in write event:", interface.fatalerror )
 549                                 interface:_close()
 550                                 interface.eventwrite = nil
 551                                 return -1
 552                         end
 553                 end
 554         end
 555
 556         interface.readcallback = function( event )  -- called on read events
 557                 --vdebug( "new client read event, id/ip/port:", tostring(interface.id), tostring(ip), tostring(port) )
 558                 if interface.noreading or interface.fatalerror then  -- leave this event
 559                         --vdebug( "leaving this event because:", tostring(interface.noreading or interface.fatalerror) )
 560                         interface.eventread = nil
 561                         return -1
 562                 end
 563                 if EV_TIMEOUT == event and not interface.conn:dirty() and interface:onreadtimeout() ~= true then
 564                         return -1 -- took too long to get some data from client -> disconnect
 565                 end
 566                 if interface._usingssl then  -- handle luasec
 567                         if interface.eventwritetimeout then  -- ok, in the past writecallback was regged
 568                                 local ret = interface.writecallback( )  -- call it
 569                                 --vdebug( "tried to write in readcallback, result:", tostring(ret) )
 570                         end
 571                         if interface.eventreadtimeout then
 572                                 interface.eventreadtimeout:close( )
 573                                 interface.eventreadtimeout = nil
 574                         end
 575                 end
 576                 local buffer, err, part = interface.conn:receive( interface._pattern )  -- receive buffer with "pattern"
 577                 --vdebug( "read data:", tostring(buffer), "error:", tostring(err), "part:", tostring(part) )
 578                 buffer = buffer or part
 579                 if buffer and #buffer > cfg.MAX_READ_LENGTH then  -- check buffer length
 580                         interface.fatalerror = "receive buffer exceeded"
 581                         debug( "fatal error:", interface.fatalerror )
 582                         interface:_close()
 583                         interface.eventread = nil
 584                         return -1
 585                 end
 586                 if err and ( err ~= "timeout" and err ~= "wantread" ) then
 587                         if "wantwrite" == err then -- need to read on write event
 588                                 if not interface.eventwrite then  -- register new write event if needed
 589                                         interface.eventwrite = addevent( base, interface.conn, EV_WRITE, interface.writecallback, cfg.WRITE_TIMEOUT )
 590                                 end
 591                                 interface.eventreadtimeout = addevent( base, nil, EV_TIMEOUT,
 592                                         function( ) interface:_close() end, cfg.READ_TIMEOUT)
 593                                 debug( "wantwrite during read attempt, reg it in writecallback but dont know what really happens next..." )
 594                                 -- to be honest i dont know what happens next, if it is allowed to first read, the write etc...
 595                         else  -- connection was closed or fatal error
 596                                 interface.fatalerror = err
 597                                 debug( "connection failed in read event:", interface.fatalerror )
 598                                 interface:_close()
 599                                 interface.eventread = nil
 600                                 return -1
 601                         end
 602                 else
 603                         interface.onincoming( interface, buffer, err )  -- send new data to listener
 604                 end
 605                 if interface.noreading then
 606                         interface.eventread = nil;
 607                         return -1;
 608                 end
 609                 if interface.conn:dirty() then -- still data left in buffer
 610                         return EV_TIMEOUT, cfg.READ_RETRY_DELAY;
 611                 end
 612                 return EV_READ, cfg.READ_TIMEOUT
 613         end
 614
 615         client:settimeout( 0 )  -- set non blocking
 616         setmetatable(interface, interface_mt)
 617         interfacelist[ interface ] = true  -- add to interfacelist
 618         return interface
 619 end
 620
 621 local function handleserver( server, addr, port, pattern, listener, sslctx )  -- creates an server interface
 622         debug "creating server interface..."
 623         local interface = {
 624                 _connections = 0;
 625
 626                 type = "server";
 627                 conn = server;
 628                 onconnect = listener.onconnect;  -- will be called when new client connected
 629                 eventread = false;  -- read event handler
 630                 eventclose = false; -- close event handler
 631                 readcallback = false; -- read event callback
 632                 fatalerror = false; -- error message
 633                 nointerface = true;  -- lock/unlock parameter
 634
 635                 _ip = addr, _port = port, _pattern = pattern,
 636                 _sslctx = sslctx;
 637         }
 638         interface.id = tostring(interface):match("%x+$");
 639         interface.readcallback = function( event )  -- server handler, called on incoming connections
 640                 --vdebug( "server can accept, id/addr/port:", interface, addr, port )
 641                 if interface.fatalerror then
 642                         --vdebug( "leaving this event because:", self.fatalerror )
 643                         interface.eventread = nil
 644                         return -1
 645                 end
 646                 local delay = cfg.ACCEPT_DELAY
 647                 if EV_TIMEOUT == event then
 648                         if interface._connections >= cfg.MAX_CONNECTIONS then  -- check connection count
 649                                 debug( "to many connections, seconds to wait for next accept:", delay )
 650                                 return EV_TIMEOUT, delay  -- timeout...
 651                         else
 652                                 return EV_READ  -- accept again
 653                         end
 654                 end
 655                 --vdebug("max connection check ok, accepting...")
 656                 local client, err = server:accept()    -- try to accept; TODO: check err
 657                 while client do
 658                         if interface._connections >= cfg.MAX_CONNECTIONS then
 659                                 client:close( )  -- refuse connection
 660                                 debug( "maximal connections reached, refuse client connection; accept delay:", delay )
 661                                 return EV_TIMEOUT, delay  -- delay for next accept attempt
 662                         end
 663                         local client_ip, client_port = client:getpeername( )
 664                         interface._connections = interface._connections + 1  -- increase connection count
 665                         local clientinterface = handleclient( client, client_ip, client_port, interface, pattern, listener, sslctx )
 666                         --vdebug( "client id:", clientinterface, "startssl:", startssl )
 667                         if has_luasec and sslctx then
 668                                 clientinterface:starttls(sslctx, true)
 669                         else
 670                                 clientinterface:_start_session( true )
 671                         end
 672                         debug( "accepted incoming client connection from:", client_ip or "<unknown IP>", client_port or "<unknown port>", "to", port or "<unknown port>");
 673
 674                         client, err = server:accept()    -- try to accept again
 675                 end
 676                 return EV_READ
 677         end
 678
 679         server:settimeout( 0 )
 680         setmetatable(interface, interface_mt)
 681         interfacelist[ interface ] = true
 682         interface:_start_session()
 683         return interface
 684 end
 685
 686 local function addserver( addr, port, listener, pattern, sslctx, startssl )  -- TODO: check arguments
 687         --vdebug( "creating new tcp server with following parameters:", addr or "nil", port or "nil", sslctx or "nil", startssl or "nil")
 688         if sslctx and not has_luasec then
 689                 debug "fatal error: luasec not found"
 690                 return nil, "luasec not found"
 691         end
 692         local server, err = socket.bind( addr, port, cfg.ACCEPT_QUEUE )  -- create server socket
 693         if not server then
 694                 debug( "creating server socket on "..addr.." port "..port.." failed:", err )
 695                 return nil, err
 696         end
 697         local interface = handleserver( server, addr, port, pattern, listener, sslctx, startssl )  -- new server handler
 698         debug( "new server created with id:", tostring(interface))
 699         return interface
 700 end
 701
 702 local function wrapclient( client, ip, port, listeners, pattern, sslctx )
 703         local interface = handleclient( client, ip, port, nil, pattern, listeners, sslctx )
 704         interface:_start_connection(sslctx)
 705         return interface, client
 706         --function handleclient( client, ip, port, server, pattern, listener, _, sslctx )  -- creates an client interface
 707 end
 708
 709 local function addclient( addr, serverport, listener, pattern, sslctx, typ )
 710         if sslctx and not has_luasec then
 711                 debug "need luasec, but not available"
 712                 return nil, "luasec not found"
 713         end
 714         if not typ then
 715                 local addrinfo, err = getaddrinfo(addr)
 716                 if not addrinfo then return nil, err end
 717                 if addrinfo[1] and addrinfo[1].family == "inet6" then
 718                         typ = "tcp6"
 719                 else
 720                         typ = "tcp"
 721                 end
 722         end
 723         local create = socket[typ]
 724         if type( create ) ~= "function"  then
 725                 return nil, "invalid socket type"
 726         end
 727         local client, err = create()  -- creating new socket
 728         if not client then
 729                 debug( "cannot create socket:", err )
 730                 return nil, err
 731         end
 732         client:settimeout( 0 )  -- set nonblocking
 733         local res, err = client:connect( addr, serverport )  -- connect
 734         if res or ( err == "timeout" ) then
 735                 local ip, port = client:getsockname( )
 736                 local interface = wrapclient( client, ip, serverport, listener, pattern, sslctx )
 737                 debug( "new connection id:", interface.id )
 738                 return interface, err
 739         else
 740                 debug( "new connection failed:", err )
 741                 return nil, err
 742         end
 743 end
 744
 745 local function loop( )  -- starts the event loop
 746         base:loop( )
 747         return "quitting";
 748 end
 749
 750 local function newevent( ... )
 751         return addevent( base, ... )
 752 end
 753
 754 local function closeallservers ( arg )
 755         for item in pairs( interfacelist ) do
 756                 if item.type == "server" then
 757                         item:close( arg )
 758                 end
 759         end
 760 end
 761
 762 local function setquitting(yes)
 763         if yes then
 764                 -- Quit now
 765                 closeallservers();
 766                 base:loopexit();
 767         end
 768 end
 769
 770 local function get_backend()
 771         return base:method();
 772 end
 773
 774 -- We need to hold onto the events to stop them
 775 -- being garbage-collected
 776 local signal_events = {}; -- [signal_num] -> event object
 777 local function hook_signal(signal_num, handler)
 778         local function _handler()
 779                 local ret = handler();
 780                 if ret ~= false then -- Continue handling this signal?
 781                         return EV_SIGNAL; -- Yes
 782                 end
 783                 return -1; -- Close this event
 784         end
 785         signal_events[signal_num] = base:addevent(signal_num, EV_SIGNAL, _handler);
 786         return signal_events[signal_num];
 787 end
 788
 789 local function link(sender, receiver, buffersize)
 790         local sender_locked;
 791
 792         function receiver:ondrain()
 793                 if sender_locked then
 794                         sender:resume();
 795                         sender_locked = nil;
 796                 end
 797         end
 798
 799         function sender:onincoming(data)
 800                 receiver:write(data);
 801                 if receiver.writebufferlen >= buffersize then
 802                         sender_locked = true;
 803                         sender:pause();
 804                 end
 805         end
 806         sender:set_mode("*a");
 807 end
 808
 809 return {
 810         cfg = cfg,
 811         base = base,
 812         loop = loop,
 813         link = link,
 814         event = levent,
 815         event_base = base,
 816         addevent = newevent,
 817         addserver = addserver,
 818         addclient = addclient,
 819         wrapclient = wrapclient,
 820         setquitting = setquitting,
 821         closeall = closeallservers,
 822         get_backend = get_backend,
 823         hook_signal = hook_signal,
 824
 825         __NAME = SCRIPT_NAME,
 826         __DATE = LAST_MODIFIED,
 827         __AUTHOR = SCRIPT_AUTHOR,
 828         __VERSION = SCRIPT_VERSION,
 829
 830 }