Lua Socket

LuaSocket is a development branch of spring:

config settings

All LuaSocket related config is readonly for LuaWidgets. They can be only changed through unitsync.

LuaSocketEnabled = 1	Default is 0 means, all Socket functions are disabled
TCPAllowConnect	allow TCP-connections to the listed hosts, for example: "springrts.com:80 springfiles.com:80"
TCPAllowListen	Server TCP-sockets are allowed on this port, for example: "localhost:1234 0.0.0.0:12345"
UDPAllowConnect	see TCPAllowConnect
UDPAllowConnect	see TCPAllowListen

dns resolving is blocking, solutions: worker thread or some lib:
- adns http://www.chiark.greenend.org.uk/~ian/adns/
- dns.c http://25thandclement.com/~william/projects/dns.c.html
- tadns http://adns.sourceforge.net/
- or a lua implementation? biggest problem would be to find the local dns-server
allow rules have exactly match the host:port in script. currently its not possible to use host:port in a lua widget and use the resolved hostname for connecting (and vice versa) (simple workaround, add both as rule)
socket=require("socket") is needed
most lua scripts from luasocket won't work as they are blocking! rewriting them non-blocking is required! (should be in most cases few work, as parsing stuff can be reused)
udp sendto isn't checked, only binding the udp-socket
config file should be better protected, see https://github.com/spring/spring/blob/develop/rts/System/Config/ConfigHandler.cpp#L289 + https://github.com/spring/spring/commit/948d6fb9d1c95b99b5cc7929cf3e0de0f9d6d93e maybe just locking the file is best?! see also http://springrts.com/mantis/view.php?id=2891 (private report)