114 lines
3.2 KiB
Lua
114 lines
3.2 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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-- Should be run in a Server Rack, with two servers, connected by Linked Cards.
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-- Each should be responsible for "it's" side.
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-- This is a piece of dedicated hardware for a specific purpose.
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-- The only reason it's not 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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-- Does the single modem connected to this server connect to the outside world?
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local outbound = false
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if #args ~= 2 then error("Expecting args: outbound ('true'/'false'), network-name") end
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if args[1] == "true" then
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outbound = true
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elseif args[1] ~= "false" then
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error("Only 'true' or 'false' are allowed for the 'outbound' argument.")
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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 event = require("event")
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local component = require("component")
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local cdlib = require("cdlib")
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local modem = component.modem
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local tunnel = component.tunnel
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-- It is possible that this is meant to be used
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-- on public wireless infrastructure -
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-- for example, if this was a server-level domain,
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-- perhaps solely connected via wireless...
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-- Oh well. It's the sysadmin's decision to connect it this way.
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-- Any wireless-abuse is the local regulator's decision.
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if modem.isWireless() then
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modem.setStrength(400)
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end
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modem.open(4957)
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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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if outbound then
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processFrom = function (from)
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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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end
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processTo = function (nto)
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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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end
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else
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processFrom = function (from)
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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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processTo = function (nto)
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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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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, to, from, port, dist, magic[6], data[7]
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if ((e[2] == tunnel.address) or (e[4] == 4957)) then
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if e[6] == "copper" then
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if type(e[7]) == "string" then
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local hops, nfrom, nto, data = cdlib.decode(e[7])
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if data then
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if e[2] == tunnel.address then
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-- Pass it on as given.
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modem.broadcast(4957, "copper", e[7])
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elseif e[2] == modem.address then
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-- Process it, then give to tunnel
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if hops ~= 255 then
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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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tunnel.send("copper", cdlib.encode(hops + 1, tfrom, tto, data))
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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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end
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end
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end
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end
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