133 lines
3.6 KiB
Lua
133 lines
3.6 KiB
Lua
-- I, 20kdc, release this into the public domain.
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-- No warranty is provided, implied or otherwise.
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-- Copper Hierarchial Gateway implementation for OpenComputers.
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-- Best run in a Server with two modems,
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-- but can be run with a support program on another computer with a modem,
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-- one modem in the main computer, and a LC pair.
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-- The only reason this isn't run on two microcontrollers is because
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-- they're inconvenient to use and cdlib needs to be there -
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-- I'm sure you can port it yourself.
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local args = {...}
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if #args ~= 2 then
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error("Expecting args: outboundModem (or 'relay' to use Linked Cards), network-name")
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end
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-- What is the name of this division, including forward-slash?
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local netname = args[2] .. "/"
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local outboundModemAdr = args[1]
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-- These names are chosen by sending direction.
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local outboundModem, inboundModem
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if outboundModemAdr == "relay" then outboundModemAdr = nil end
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local event = require("event")
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local component = require("component")
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local cdlib = require("cdlib")
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for a, _ in component.list("modem") do
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if outboundModemAdr and (a:sub(1, outboundModemAdr:len()) == outboundModemAdr) then
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if outboundModem then error("Outbound modem ambiguous.") end
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outboundModem = component.proxy(a)
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else
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if inboundModem then error("More than one internal-side modem.") end
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inboundModem = component.proxy(a)
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end
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end
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inboundModem.open(4957)
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if not outboundModem then
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local tunnel = component.tunnel
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-- Implement just enough of an outbound modem to be useful.
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outboundModem = {
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address = tunnel.address,
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broadcast = function (port, ...)
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tunnel.send(...)
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end
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}
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else
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outboundModem.open(4957)
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end
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------ By this point, inboundModem and outboundModem must be:
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-- 1. non-nil
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-- 2. have the address and broadcast(port, ...) fields
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-- (Also, if outboundModemAdr == nil then the port will be ignored for it.)
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-- Rules used on messages coming in from the 'modem' side.
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-- (This implies Tunnel packets are trusted absolutely - which is correct.)
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local processFrom, processTo
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-- Implementation of the rules described in protocol.1 for more or
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-- less unambiguous name translation.
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-- "incoming" is parent-side, incoming being false means child-side.
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processFrom = function (incoming, from)
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if incoming then
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if from:sub(1, netname:len()) == netname then
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return
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end
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return "<" .. from
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else
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if from:sub(1, 1) == "<" then
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return
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end
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return netname .. from
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end
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end
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processTo = function (incoming, nto)
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if incoming then
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if nto:sub(1, netname:len()) ~= netname then
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return
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end
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return nto:sub(netname:len() + 1)
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else
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if nto:sub(1, 1) ~= "<" then
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return
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end
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return nto:sub(2)
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end
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end
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local function checkLen(s)
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if not s then return end
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if s:len() == 0 then return end
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if s:len() > 256 then return end
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return s
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end
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local function handlePacket(incoming, dat)
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local hops, nfrom, nto, data = cdlib.decode(dat)
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if not data then return end -- corrupt packet
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if hops == 255 then return end
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local tfrom, tto = checkLen(processFrom(nfrom)), checkLen(processTo(nto))
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if tfrom and tto then
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local resdata = cdlib.encode(hops + 1, tfrom, tto, data)
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if incoming then
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inboundModem.broadcast(4957, "copper", resdata)
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else
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outboundModem.broadcast(4957, "copper", resdata)
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end
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end
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end
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while true do
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local e = {event.pull("modem_message")}
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if e[1] == "modem_message" then
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-- type, receiver, sender, port, dist, magic, data
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if (e[2] == inboundModem.address) or (e[2] == outboundModem.address) then
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local incoming = e[2] == outboundModem.address
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if (e[4] == 4957) or (incoming and (outboundModemAdr == nil)) then
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if (e[6] == "copper") and e[7] then
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handlePacket(incoming, e[7])
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end
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end
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end
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end
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end
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