source/texk/web2c/luatexdir/luasocket/etc/forward.lua

   1 -- load our favourite library
   2 local dispatch = require("dispatch")
   3 local handler = dispatch.newhandler()
   4
   5 -- make sure the user knows how to invoke us
   6 if table.getn(arg) < 1 then
   7     print("Usage")
   8     print("    lua forward.lua <iport:ohost:oport> ...")
   9     os.exit(1)
  10 end
  11
  12 -- function to move data from one socket to the other
  13 local function move(foo, bar)
  14     local live
  15     while 1 do
  16         local data, error, partial = foo:receive(2048)
  17         live = data or error == "timeout"
  18         data = data or partial
  19         local result, error = bar:send(data)
  20         if not live or not result then
  21             foo:close()
  22             bar:close()
  23             break
  24         end
  25     end
  26 end
  27
  28 -- for each tunnel, start a new server
  29 for i, v in ipairs(arg) do
  30     -- capture forwarding parameters
  31     local _, _, iport, ohost, oport = string.find(v, "([^:]+):([^:]+):([^:]+)")
  32     assert(iport, "invalid arguments")
  33     -- create our server socket
  34     local server = assert(handler.tcp())
  35     assert(server:setoption("reuseaddr", true))
  36     assert(server:bind("*", iport))
  37     assert(server:listen(32))
  38     -- handler for the server object loops accepting new connections
  39     handler:start(function()
  40         while 1 do
  41             local client = assert(server:accept())
  42             assert(client:settimeout(0))
  43             -- for each new connection, start a new client handler
  44             handler:start(function()
  45                 -- handler tries to connect to peer
  46                 local peer = assert(handler.tcp())
  47                 assert(peer:settimeout(0))
  48                 assert(peer:connect(ohost, oport))
  49                 -- if sucessful, starts a new handler to send data from
  50                 -- client to peer
  51                 handler:start(function()
  52                     move(client, peer)
  53                 end)
  54                 -- afte starting new handler, enter in loop sending data from
  55                 -- peer to client
  56                 move(peer, client)
  57             end)
  58         end
  59     end)
  60 end
  61
  62 -- simply loop stepping the server
  63 while 1 do
  64     handler:step()
  65 end