Basic Rednet relay/forwarding/remote file server/gps host program

local tArgs = { ... }
local function opnmdm()
	for i,v in pairs(rs.getSides()) do	
		if peripheral.getType(v) == "modem" then
			if not rednet.isOpen(v) then rednet.open(v) end
		return true end
	end
return false end
local dmnlst,rlylst,hstID,sndr,mssg,dstnc,cmnd,prm1,xclst = {},{},os.computerID(),tonumber(tArgs[5])
local hstfnc = {
PING = function() rednet.send(sndr,textutils.serialize({xPos,yPos,zPos})) end,
access = function(acsdx) if dmnlst[sndr] then
	local tp = {acsdx:match("(%S+)%s*(%S+)%s*(.*)")}
	tp[4] = tonumber(tp[2])
	if tp[1] == "add" then tp[5] = true elseif tp[1] ~= "ban" then acsdx = nil end
	if tp[3] == "dmnlst" then tp[6] = dmnlst elseif tp[3] == "xclst" then
		if not xclst then xclst = {} end tp[6] = xclst
	else acsdx = nil end
	if tp[4] and acsdx then tp[6][tp[4]] = tp[5]
	tp[7] = fs.open(tp[3],"w") tp[7].writeLine(textutils.serialize(tp[6])) tp[7].close()
	else rednet.send(sndr,"Usage 'access add/ban ID dmnlst/xclst'") end
end end,
bcst = function(bmssg) if dmnlst[sndr] then
	if bmssg then rednet.send(nil,bmssg) end
end end,
del = function(flnm) if dmnlst[sndr] then
	flnm = flnm:match("%S+")
	if fs.exists(flnm) and not flnm == "/" then fs.delete(flnm) rednet.send(sndr,flnm.." deleted")
	else rednet.send(sndr,"File not found") end
end end,
dir = function(flnm)
	flnm = flnm:match("%S+")
	local tdir = fs.list(flnm)
	for i = 1,#tdir do rednet.send(sndr,tdir[i]) end
end,
drp = function()
	local rID = rlylst[sndr]
	rlylst[sndr],rlylst[rID] = nil
	local hndl = fs.open("rlylst","w")
	hndl.write(textutils.serialize(rlylst)) hndl.close()
	rednet.send(sndr,"Relay to ID"..rID.." dropped")
end,
fwd = function(frwd)
	local rID,fmssg = frwd:match("(%d+)%s*(.*)$")
	rID = tonumber(rID)
	if rID and fmssg then rednet.send(rID,fmssg) end
end,
hsts = function() if dmnlst[sndr] then
	local ndx,hstlst = 0,{}
	rednet.broadcast("PING")
	repeat ndx = ndx+1
		hstlst[ndx] = {rednet.receive(0.5)}
	until not hstlst[ndx][1]
	rednet.send(sndr,textutils.serialize(hstlst))
end end,
reboot = function() if dmnlst[sndr] then shell.run("reboot") end end,
rly = function(rlyID)
	local rID = tonumber(rlyID)
	rlylst[sndr],rlylst[rID] = rID,sndr
	local hndl = fs.open("rlylst","w")
	hndl.write(textutils.serialize(rlylst)) hndl.close()
	rednet.send(sndr,"Relaying to ID"..rlylst[sndr])
end,
rcvfl = function(flnm) if dmnlst[sndr] then
	local tp = {flnm:match("(%S+)%s*(.*)")}
	 tp[3] = fs.open(tp[1],"w") if tp[3] then tp[3].write(tp[2]) tp[3].close()
	rednet.send(sndr,tp[1].." Updated")
	else rednet.send(sndr,"File is Read Only") end
end end,
srvfl = function(flnm)
	flnm = flnm:match("%S+")
	local hndl = fs.open(flnm,"r")
	if hndl then rednet.send(sndr,hndl.readAll()) hndl.close()
	else rednet.send(sndr,"File not found") end
end,
}

if opnmdm() then
	xPos,yPos,zPos = gps.locate(2,true )
	if tArgs[1] == "host" then
		if not xPos then xPos,yPos,zPos = tArgs[2],tArgs[3],tArgs[4]
			local itr8 = 0
			while not (xPos and yPos and zPos) do
				write("Enter x coordinate: ") xPos = tonumber(read())
				write("Enter y coordinate: ") yPos = tonumber(read())
				write("Enter z coordinate: ") zPos = tonumber(read())
				itr8 = itr8+1
				if itr8 > 3 then print("Invalid input") return false end
			end
		end
		print("GPS/Relay Node position "..xPos..","..yPos..","..zPos)
		local hndl = fs.open("startup","w")
		hndl.writeLine("shell.run("rnhst","host","..xPos..","..yPos..","..zPos..")")
		hndl.close()
		if sndr then hndl,xclst,dmnlst = fs.open("xclst","w"),{[sndr] = true},{[sndr] = true}
			hndl.writeLine(textutils.serialize(xclst)) hndl.close()
		elseif fs.exists("xclst") then hndl = fs.open("xclst","r")
			xclst = textutils.unserialize(hndl.readAll()) hndl.close()
		end
		if fs.exists("rlylst") then hndl = fs.open("rlylst","r")
			rlylst = textutils.unserialize(hndl.readAll()) hndl.close()
		end
		if fs.exists("dmnlst") then hndl = fs.open("dmnlst","r")
			dmnlst = textutils.unserialize(hndl.readAll()) hndl.close()
		else hndl = fs.open("dmnlst","w") hndl.writeLine(textutils.serialize(dmnlst)) hndl.close()end
		repeat sndr,mssg,dstnc = rednet.receive()
			if rlylst[hstID] then rednet.send(rlylst[hstID],sndr..":"..mssg) end
			if xclst and not xclst[sndr] then cmnd = "none" else
				cmnd,prm1 = mssg:match("^(%S+)%s*(.*)")
				if prm1 == "" then prm1 = "/" end
				if hstfnc[cmnd] then hstfnc[cmnd](prm1) end
			end
			if rlylst[sndr] and not hstfnc[cmnd] then rednet.send(rlylst[sndr],mssg) end
		until not hstID
	return true end
else print("could not open modem") return false
end