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dsnet
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dsnet
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// message:
// source
// dest
// message_id
// message
local sOpenedSide = nil
local bDebug = true
local iMyId = os.getComputerId()
local function debug(msg)
if bDebug then
print(msg)
end
end
function open(sSide)
local bOpen, sFreeSide = false, nil
if sSide != nil then
if peripheral.getType( sSide ) == "modem" then
debug( "Opening "..sSide.." modem" )
rednet.open( sSide )
if rednet.isOpen( sSide ) then
debug("Rednet open on "..sSide)
bOpen = true
else
debug("Rednet did not open on "..sSide)
bOpen = false
end
end
return bOpen
else
for n,sSide in pairs(rs.getSides()) do
if peripheral.getType( sSide ) == "modem" then
sFreeSide = sSide
if rednet.isOpen( sSide ) then
bOpen = true
break
end
end
end
end
if not bOpen then
if sFreeSide then
print( "No modem active. Opening "..sFreeSide.." modem" )
rednet.open( sFreeSide )
sOpenedSide = sFreeSide
return true
else
print( "No modem attached" )
return false
end
end
return true
end
local iLastMsgId = 0
local iTimeout = 2
local iLastGateway = -1
local fLastGatewayClock = -1
local fGatewayUpdateTimeout = 5 * 60 -- 5 real minutes
local function createMsg(type, data)
return { msgType: type, data: data}
end
local function msgToString(msg)
local sMsg = nil
if type(msg) == "table" then
sMsg = textutils.serialize(msg)
else
sMsg = tostring(msg)
end
return sMsg
end
local function broadcast(msg)
rednet.broadcast("DSNET " .. msgToString(msg))
end
local function route(gw, msg)
rednet.send(gw, "DSNET " .. msgToString(createMsg("ROUTE",msg)))
end
local function parseMessage(msg)
if string.find(msg, "DSNET") != 1 then
return false
end
return true, textutils.unserialize(string.sub(msg, 7))
end
local function getGateway()
local fClock = os.clock()
if fClock > fLastGatewayClock + fGatewayUpdateTimeout then
broadcast(createMsg("GATEWAY_DISCOVERY"))
local iBestGateway = -1
local fBestGatewayDistance = -1
local fStartClock = os.clock()
while os.clock < fStartClock + iTimeout do
local sender,message,distance = rednet.receive()
local isMsg, msg = parseMessage(message)
if isMsg && msg["msgType"] == "GATEWAY_OFFER" then
if fBestGatewayDistance == -1 || fBestGatewayDistance > distance then
fBestGatewayDistance = distance
iBestGateway = sender
end
end
end
if iBestGateway == -1 then
debug("couldnt find a gateway")
iLastGateway = -1
else
debug("using gateway " .. iBestGateway)
iLastGateway = iBestGateway
end
end
return iLastGateway
end
// message:
// msgId
// src
// dest
// msg
function send(dest, msg)
local tMsg = {}
iLastMsgId = iLastMsgId + 1
tMsg["msgId"] = iLastMsgId
tMsg["src"] = iMyId
tMsg["dest"] = dest
tMsg["msg"] = msg
local gw = getGateway()
if gw > 0 then
route(tMsg)
else
debug("couldn't find gateway")
end
end
local msgBuffer = {}
function clientLoop()
while true do
sender, msg, distance = rednet.receive()
isMsg, m = parseMessage(msg)
if isMsg then
if m["msgType"] == "PING" then
rednet.send(sender, "DSNET " .. msgToString(createMsg("PONG")))
else
table.insert(m)
end
end
end
end
function receive(wait)
repeat
m = table.remove(msgBuffer,1)
until !wait || m
end
local tLocalClients = {}
local fPingTimeout = 2 -- seconds
local fClientStale = 5*60 -- 5 real minutes
local fFindHopTimeout = 8 -- seconds
local function pingClient(id)
rednet.send(id, "DSNET " .. msgToString(createMsg("PING")))
local startTime = os.clock()
while os.clock() < startTime + fPingTimeout do
sender, msg, distance = rednet.receive()
isMsg, m = parseMessage(msg)
if isMsg then
if m["msgType"] == "PONG" then
tLocalClients[id] = os.clock()
return true
end
handleMsg(sender, m, distance)
end
end
return false
end
local function findHop(dest)
rednet.broadcast("DSNET " .. msgToSTring(createMsg("FINDHOP", dest)))
local startTime = os.clock()
local bestHop = -1
local bestHopDist = -1
while os.clock() < startTime + fFindHopTimeout do
sender, msg, distance = rednet.receive()
isMsg, m = parseMessage(msg)
if isMsg then
if m["msgType"] == "HOP" then
if bestHopDist == -1 || m["data"] < bestHopDist then
bestHopDist = innerMsg["data"]
bestHop = m["src"]
end
else
handleMsg(sender, m, distance)
end
end
end
if bestHop > 0 then
tRemoteClients[dest] = { ping: os.clock(), hop: bestHop}
else
tRemoteClients[dest] = nil
end
end
local function handleMsg(sender, msg, distance)
if isMsg then
local msgType = m["msgType"]
if msgType == "ROUTE" then
dest = m["dest"]
lastPing = tLocalClients[dest]
if !lastPing then
if tRemoteClients[dest] then
lastPing = tRemoteClients[dest]["ping"]
end
end
if !lastPing || lastPing + fClientStale < os.clock() then
if pingClient(dest) then
rednet.send(dest, "DSNET " .. msgToString(msg))
else
hop = findHop(dest)
if hop then
rednet.send(hop, "DSNET " .. msgToString(msg))
else
debug("couldn't find next hop")
end
end
else
rednet.send(dest, "DSNET " .. msgToString(msg))
end
elseif msgType == "FINDHOP" then
end
end
end
function routerLoop()
while true do
sender, msg, distance = rednet.receive()
isMsg, m = parseMessage(msg)
if isMsg then
handleMsg(sender, m, distance)
end
end
end
-- vim: ft=lua