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opus/sys/services/transort.lua
2017-05-12 01:12:58 -04:00

106 lines
2.6 KiB
Lua

--[[
Low level socket protocol implementation.
* sequencing
* write acknowledgements
* background read buffering
]]--
multishell.setTitle(multishell.getCurrent(), 'Net transport')
local computerId = os.getComputerID()
_G.transport = {
timers = { },
sockets = { },
}
function transport.open(socket)
transport.sockets[socket.sport] = socket
end
function transport.read(socket)
local data = table.remove(socket.messages, 1)
if data then
return unpack(data)
end
end
function transport.write(socket, data)
--debug('>> ' .. Util.tostring({ type = 'DATA', seq = socket.wseq }))
socket.transmit(socket.dport, socket.dhost, data)
local timerId = os.startTimer(2)
transport.timers[timerId] = socket
socket.timers[socket.wseq] = timerId
socket.wseq = socket.wseq + 1
end
function transport.close(socket)
transport.sockets[socket.sport] = nil
end
print('Net transport started')
while true do
local e, timerId, dport, dhost, msg, distance = os.pullEvent()
if e == 'timer' then
local socket = transport.timers[timerId]
if socket and socket.connected then
print('transport timeout - closing socket ' .. socket.sport)
socket:close()
transport.timers[timerId] = nil
end
elseif e == 'modem_message' and dhost == computerId and msg then
local socket = transport.sockets[dport]
if socket and socket.connected then
--if msg.type then debug('<< ' .. Util.tostring(msg)) end
if msg.type == 'DISC' then
-- received disconnect from other end
socket.connected = false
socket:close()
elseif msg.type == 'ACK' then
local timerId = socket.timers[msg.seq]
os.cancelTimer(timerId)
socket.timers[msg.seq] = nil
transport.timers[timerId] = nil
elseif msg.type == 'PING' then
socket.transmit(socket.dport, socket.dhost, {
type = 'ACK',
seq = msg.seq,
})
elseif msg.type == 'DATA' and msg.data then
if msg.seq ~= socket.rseq then
print('transport seq error - closing socket ' .. socket.sport)
socket:close()
else
socket.rseq = socket.rseq + 1
table.insert(socket.messages, { msg.data, distance })
-- use resume instead ??
if not socket.messages[2] then -- table size is 1
os.queueEvent('transport_' .. socket.sport)
end
--debug('>> ' .. Util.tostring({ type = 'ACK', seq = msg.seq }))
socket.transmit(socket.dport, socket.dhost, {
type = 'ACK',
seq = msg.seq,
})
end
end
end
end
end