cc-mek-scada/rtu/rtu.lua
2022-06-05 11:16:25 -04:00

420 lines
14 KiB
Lua

local comms = require("scada-common.comms")
local ppm = require("scada-common.ppm")
local log = require("scada-common.log")
local types = require("scada-common.types")
local util = require("scada-common.util")
local modbus = require("rtu.modbus")
local rtu = {}
local rtu_t = types.rtu_t
local PROTOCOLS = comms.PROTOCOLS
local SCADA_MGMT_TYPES = comms.SCADA_MGMT_TYPES
local RTU_UNIT_TYPES = comms.RTU_UNIT_TYPES
local print = util.print
local println = util.println
local print_ts = util.print_ts
local println_ts = util.println_ts
-- create a new RTU
function rtu.init_unit()
local self = {
discrete_inputs = {},
coils = {},
input_regs = {},
holding_regs = {},
io_count_cache = { 0, 0, 0, 0 }
}
local insert = table.insert
---@class rtu_device
local public = {}
---@class rtu
local protected = {}
-- refresh IO count
local function _count_io()
self.io_count_cache = { #self.discrete_inputs, #self.coils, #self.input_regs, #self.holding_regs }
end
-- return IO count
---@return integer discrete_inputs, integer coils, integer input_regs, integer holding_regs
function public.io_count()
return self.io_count_cache[1], self.io_count_cache[2], self.io_count_cache[3], self.io_count_cache[4]
end
-- discrete inputs: single bit read-only
-- connect discrete input
---@param f function
---@return integer count count of discrete inputs
function protected.connect_di(f)
insert(self.discrete_inputs, { read = f })
_count_io()
return #self.discrete_inputs
end
-- read discrete input
---@param di_addr integer
---@return any value, boolean access_fault
function public.read_di(di_addr)
ppm.clear_fault()
local value = self.discrete_inputs[di_addr].read()
return value, ppm.is_faulted()
end
-- coils: single bit read-write
-- connect coil
---@param f_read function
---@param f_write function
---@return integer count count of coils
function protected.connect_coil(f_read, f_write)
insert(self.coils, { read = f_read, write = f_write })
_count_io()
return #self.coils
end
-- read coil
---@param coil_addr integer
---@return any value, boolean access_fault
function public.read_coil(coil_addr)
ppm.clear_fault()
local value = self.coils[coil_addr].read()
return value, ppm.is_faulted()
end
-- write coil
---@param coil_addr integer
---@param value any
---@return boolean access_fault
function public.write_coil(coil_addr, value)
ppm.clear_fault()
self.coils[coil_addr].write(value)
return ppm.is_faulted()
end
-- input registers: multi-bit read-only
-- connect input register
---@param f function
---@return integer count count of input registers
function protected.connect_input_reg(f)
insert(self.input_regs, { read = f })
_count_io()
return #self.input_regs
end
-- read input register
---@param reg_addr integer
---@return any value, boolean access_fault
function public.read_input_reg(reg_addr)
ppm.clear_fault()
local value = self.input_regs[reg_addr].read()
return value, ppm.is_faulted()
end
-- holding registers: multi-bit read-write
-- connect holding register
---@param f_read function
---@param f_write function
---@return integer count count of holding registers
function protected.connect_holding_reg(f_read, f_write)
insert(self.holding_regs, { read = f_read, write = f_write })
_count_io()
return #self.holding_regs
end
-- read holding register
---@param reg_addr integer
---@return any value, boolean access_fault
function public.read_holding_reg(reg_addr)
ppm.clear_fault()
local value = self.holding_regs[reg_addr].read()
return value, ppm.is_faulted()
end
-- write holding register
---@param reg_addr integer
---@param value any
---@return boolean access_fault
function public.write_holding_reg(reg_addr, value)
ppm.clear_fault()
self.holding_regs[reg_addr].write(value)
return ppm.is_faulted()
end
-- public RTU device access
-- get the public interface to this RTU
function protected.interface()
return public
end
return protected
end
-- RTU Communications
---@param version string
---@param modem table
---@param local_port integer
---@param server_port integer
---@param conn_watchdog watchdog
function rtu.comms(version, modem, local_port, server_port, conn_watchdog)
local self = {
version = version,
seq_num = 0,
r_seq_num = nil,
txn_id = 0,
modem = modem,
s_port = server_port,
l_port = local_port,
conn_watchdog = conn_watchdog
}
---@class rtu_comms
local public = {}
local insert = table.insert
-- open modem
if not self.modem.isOpen(self.l_port) then
self.modem.open(self.l_port)
end
-- PRIVATE FUNCTIONS --
-- send a scada management packet
---@param msg_type SCADA_MGMT_TYPES
---@param msg table
local function _send(msg_type, msg)
local s_pkt = comms.scada_packet()
local m_pkt = comms.mgmt_packet()
m_pkt.make(msg_type, msg)
s_pkt.make(self.seq_num, PROTOCOLS.SCADA_MGMT, m_pkt.raw_sendable())
self.modem.transmit(self.s_port, self.l_port, s_pkt.raw_sendable())
self.seq_num = self.seq_num + 1
end
-- keep alive ack
---@param srv_time integer
local function _send_keep_alive_ack(srv_time)
_send(SCADA_MGMT_TYPES.KEEP_ALIVE, { srv_time, util.time() })
end
-- PUBLIC FUNCTIONS --
-- send a MODBUS TCP packet
---@param m_pkt modbus_packet
function public.send_modbus(m_pkt)
local s_pkt = comms.scada_packet()
s_pkt.make(self.seq_num, PROTOCOLS.MODBUS_TCP, m_pkt.raw_sendable())
self.modem.transmit(self.s_port, self.l_port, s_pkt.raw_sendable())
self.seq_num = self.seq_num + 1
end
-- reconnect a newly connected modem
---@param modem table
---@diagnostic disable-next-line: redefined-local
function public.reconnect_modem(modem)
self.modem = modem
-- open modem
if not self.modem.isOpen(self.l_port) then
self.modem.open(self.l_port)
end
end
-- unlink from the server
---@param rtu_state rtu_state
function public.unlink(rtu_state)
rtu_state.linked = false
self.r_seq_num = nil
end
-- close the connection to the server
---@param rtu_state rtu_state
function public.close(rtu_state)
self.conn_watchdog.cancel()
public.unlink(rtu_state)
_send(SCADA_MGMT_TYPES.CLOSE, {})
end
-- send capability advertisement
---@param units table
function public.send_advertisement(units)
local advertisement = { self.version }
for i = 1, #units do
local unit = units[i] --@type rtu_unit_registry_entry
local type = comms.rtu_t_to_unit_type(unit.type)
if type ~= nil then
local advert = {
type,
unit.index,
unit.reactor
}
if type == RTU_UNIT_TYPES.REDSTONE then
insert(advert, unit.device)
end
insert(advertisement, advert)
end
end
_send(SCADA_MGMT_TYPES.RTU_ADVERT, advertisement)
end
-- parse a MODBUS/SCADA packet
---@param side string
---@param sender integer
---@param reply_to integer
---@param message any
---@param distance integer
---@return modbus_frame|mgmt_frame|nil packet
function public.parse_packet(side, sender, reply_to, message, distance)
local pkt = nil
local s_pkt = comms.scada_packet()
-- parse packet as generic SCADA packet
s_pkt.receive(side, sender, reply_to, message, distance)
if s_pkt.is_valid() then
-- get as MODBUS TCP packet
if s_pkt.protocol() == PROTOCOLS.MODBUS_TCP then
local m_pkt = comms.modbus_packet()
if m_pkt.decode(s_pkt) then
pkt = m_pkt.get()
end
-- get as SCADA management packet
elseif s_pkt.protocol() == PROTOCOLS.SCADA_MGMT then
local mgmt_pkt = comms.mgmt_packet()
if mgmt_pkt.decode(s_pkt) then
pkt = mgmt_pkt.get()
end
else
log.error("illegal packet type " .. s_pkt.protocol(), true)
end
end
return pkt
end
-- handle a MODBUS/SCADA packet
---@param packet modbus_frame|mgmt_frame
---@param units table
---@param rtu_state rtu_state
function public.handle_packet(packet, units, rtu_state)
if packet ~= nil then
-- check sequence number
if self.r_seq_num == nil then
self.r_seq_num = packet.scada_frame.seq_num()
elseif rtu_state.linked and self.r_seq_num >= packet.scada_frame.seq_num() then
log.warning("sequence out-of-order: last = " .. self.r_seq_num .. ", new = " .. packet.scada_frame.seq_num())
return
else
self.r_seq_num = packet.scada_frame.seq_num()
end
-- feed watchdog on valid sequence number
self.conn_watchdog.feed()
local protocol = packet.scada_frame.protocol()
if protocol == PROTOCOLS.MODBUS_TCP then
local return_code = false
local reply = modbus.reply__neg_ack(packet)
-- handle MODBUS instruction
if packet.unit_id <= #units then
local unit = units[packet.unit_id] ---@type rtu_unit_registry_entry
local unit_dbg_tag = " (unit " .. packet.unit_id .. ")"
if unit.name == "redstone_io" then
-- immediately execute redstone RTU requests
return_code, reply = unit.modbus_io.handle_packet(packet)
if not return_code then
log.warning("requested MODBUS operation failed" .. unit_dbg_tag)
end
else
-- check validity then pass off to unit comms thread
return_code, reply = unit.modbus_io.check_request(packet)
if return_code then
-- check if there are more than 3 active transactions
-- still queue the packet, but this may indicate a problem
if unit.pkt_queue.length() > 3 then
reply = unit.modbus_io.reply__srv_device_busy(packet)
log.debug("queueing new request with " .. unit.pkt_queue.length() ..
" transactions already in the queue" .. unit_dbg_tag)
end
-- always queue the command even if busy
unit.pkt_queue.push_packet(packet)
else
log.warning("cannot perform requested MODBUS operation" .. unit_dbg_tag)
end
end
else
-- unit ID out of range?
reply = modbus.reply__gw_unavailable(packet)
log.error("received MODBUS packet for non-existent unit")
end
public.send_modbus(reply)
elseif protocol == PROTOCOLS.SCADA_MGMT then
-- SCADA management packet
if packet.type == SCADA_MGMT_TYPES.KEEP_ALIVE then
-- keep alive request received, echo back
if packet.length == 1 then
local timestamp = packet.data[1]
local trip_time = util.time() - timestamp
if trip_time > 500 then
log.warning("RTU KEEP_ALIVE trip time > 500ms (" .. trip_time .. "ms)")
end
-- log.debug("RTU RTT = " .. trip_time .. "ms")
_send_keep_alive_ack(timestamp)
else
log.debug("SCADA keep alive packet length mismatch")
end
elseif packet.type == SCADA_MGMT_TYPES.CLOSE then
-- close connection
self.conn_watchdog.cancel()
public.unlink(rtu_state)
println_ts("server connection closed by remote host")
log.warning("server connection closed by remote host")
elseif packet.type == SCADA_MGMT_TYPES.REMOTE_LINKED then
-- acknowledgement
rtu_state.linked = true
self.r_seq_num = nil
elseif packet.type == SCADA_MGMT_TYPES.RTU_ADVERT then
-- request for capabilities again
public.send_advertisement(units)
else
-- not supported
log.warning("RTU got unexpected SCADA message type " .. packet.type)
end
else
-- should be unreachable assuming packet is from parse_packet()
log.error("illegal packet type " .. protocol, true)
end
end
end
return public
end
return rtu