Some metaserver logic.

build.sh

@@ -0,0 +1,10 @@
+
+SRC_DIR="src"
+LOVE_DIR="../../love"
+BUILD_DIR="build"
+
+cp -r $SRC_DIR/ $BUILD_DIR/
+cd $BUILD_DIR/
+zip -9 -r vision.love
+
+cat ../../love/love.exe vision.love > vision.exe

src/metaserver.lua

@@ -1,20 +1,86 @@
+local SERVERTIMEOUT = 30
+local CLIENTTIMEOUT = 1
+
 local shared = assert( require 'shared' )
 local socket = assert( require 'socket' )
+local packet = assert( shared.packet )
 local udp = assert( socket.udp() )
 
 --Servers broadcast their information here.
 --The metaserver builds a list of available servers. ( available meaning, "broadcasted in last ten heartbeats" )
 --Clients ask the metaserver for this list ( maybe with some filter? )
+local servers = {}
+local clients = {}
 
-local serverInfo = {}
-local serverIPs = {}
-local clientIPs = {}
+local handlers = setmetatable({
 
-local function Parse( packet, ip, port )
-  
+    serverInfo = function( svInfo, ip, port )
+      if ip ~= tostring( svInfo.ip ) then return print("Server IP mismatch:", ip, svInfo.ip) end
+      local t = socket.gettime()
+      if not servers[ip] then servers[ip] = { ip = ip, port = port, info = svInfo } end
+      servers[ip].time = t
+      packet.advertised{ time = t }
+      
+      local p = packet.get()
+      for i = 1, 10 do udp:sendto( p, ip, port ) end
+    end,
+    
+    default = function( s, ip, port )
+      print( ip, port, "Malformed message: ", s )
+    end,
+
+    metaServer = function()
+
+    end,
+
+    clientInfo = function( clientInfo, ip, port )
+      if ip ~= tostring( clientInfo.ip ) then 
+        return print( ip, port, "Client IP mismatch:", clientInfo.ip )
+      end
+      
+      if clients[ip] then print( ip, port, "Client request timeout." ) end
+      
+      local t = socket.gettime()
+      clients[ip].time = t
+      
+      for i, server in ipairs( servers ) do
+        packet.serverInfo( server.info )
+      end
+      
+      local p = packet.get()
+      for i = 1, 10 do udp:sendto( p, ip, port ) end
+    end
+  },
+
+  {
+    __index = function(t) return t.default end
+  })
+
+local function read(msg, ip, port)
+  if not msg then return end
+  local msgs, types = packet.deserialise( msg )
+  if types[1] ~= "metaServer" then 
+    print( ip, port, "Dropped packet, no padding." )
+    return read( udp:receivefrom() )
+  end
+  for i = 1, #msgs do
+    handlers[ types[i] ]( msgs[i], ip, port )
+  end
+  return read( udp:receivefrom() )
+end
+
+local function prune( t )
+  print( "Pruning", socket.gettime() )
+  for ip, server in pairs(servers) do
+    if server.time < t - SERVERTIMEOUT then
+      servers[ip] = nil
+    end
+  end
 end
 
 print( "Starting Metaserver", socket.gettime() )
-repeat
-  
-until socket.sleep( 2.0 - (socket.gettime() % 2.0) )
+repeat 
+  read( udp:receivefrom() )
+  prune( socket.gettime() )
+  io.flush()
+until socket.sleep( 2.0 )

src/server.lua

@@ -14,7 +14,7 @@ local svInfo = { version = 13,
 
 local server = { tick = 0 }
 
-local msIP, msPort
+local msIP, msPort = "127.0.0.0", 8
 
 local clients = {}
 
@@ -35,7 +35,10 @@ function server.StartLocalClient()
 end
 
 function server.Advertise()
-  udp:sendto( packet.get( packet.serverInfo( svInfo ) ) , msIP, msPort )
+  print( socket.gettime(), "Advertise." )
+  packet.metaServer{ padding = "" }
+  packet.serverInfo( svInfo )
+  udp:sendto( packet.get() , msIP, msPort )
 end
 
 --Incoming packet.
@@ -61,10 +64,14 @@ function server.Start()
   server.SetIP( socket.dns.toip(socket.dns.gethostname()), 51312 )
   assert( udp:setsockname( tostring( svInfo.ip ), svInfo.port ))
   server.StartLocalClient()
+  print( socket.gettime(), "Start." )
   repeat
     server.Parse( udp:receivefrom() )
     server.Advance()
-  until socket.sleep( 0.1 - (socket.gettime() % 0.1) )
+    if server.tick % 20 == 0 then
+      server.Advertise()
+    end
+  until socket.sleep( 0.1 )
 end
 
 function server.Advance()

src/shared/packet.lua

@@ -8,9 +8,10 @@ local function newStruct( t )
   assert( not( packet[ t.name ] or packet[ t.netname ] ))
   packet[ t.name ] = t
   packet[ t.netname ] = t
-  ffi.cdef( ("typedef struct {uint8_t netname;\n%s;\n} %s;"):format( table.concat( t, ";\n" ) , t.name ) )
+  ffi.cdef(("typedef struct {uint8_t netname;\n%s;\n} %s;"):format( table.concat( t, ";\n" ), t.name ))
   t.ct = ffi.typeof( ffi.new( t.name ) )
   t.size = ffi.sizeof( t.ct )
+  assert( t.size < 500, t.name )
   setmetatable( t, mt )
 
   --print( "Packet:", t.name, "Members:", #t + 1, "Size:", t.size, "Alignment:", ffi.alignof( t.ct ) )
@@ -29,9 +30,15 @@ newStruct{
 }
 
 newStruct{
-  name = "requestServers",
+  name = "clientInfo",
+  netname =        22,
+  "char username[31]",
+}
+
+newStruct{
+  name = "metaServer",
   netname =       123,
-  "char   padding[999]"
+  "char   padding[300]" --Just a bunch of padding to mitigate amplification. 
 }
 
 newStruct{
@@ -84,6 +91,12 @@ newStruct{
   "char   command",
 }
 
+newStruct{
+  name =  "advertised",
+  netname =        144,
+  "uint32_t      time",
+}
+
 local readBuffer = buffer.new( 1024 )
 function packet.deserialise( str )
   readBuffer:set( str )
@@ -117,7 +130,7 @@ end
 
 local writeBuffer = buffer.new( 1024 )
 function packet.add( struct, data )
-  local str = ffi.new( struct.ct, data )
+  local str = ffi.new( struct.ct, data or 0 )
   str.netname = assert( struct.netname )
   writeBuffer:putcdata( str, struct.size )
   return writeBuffer
@@ -129,7 +142,7 @@ end
 
 mt.__call = packet.add
 
-local testing = true
+local testing = testing
 --TESTS--
 if testing then