Move common code to knx.lua, remove bin.lua dependency

nselib/knx.lua

@@ -0,0 +1,83 @@
+--- Functions for communicating with Konnex (KNX) devices
+
+
+local ipOps = require "ipOps"
+local string = require "string"
+local _ENV = {}
+
+knxServiceFamilies = {
+  [0x02]="KNXnet/IP Core",
+  [0x03]="KNXnet/IP Device Management",
+  [0x04]="KNXnet/IP Tunnelling",
+  [0x05]="KNXnet/IP Routing",
+  [0x06]="KNXnet/IP Remote Logging",
+  [0x08]="KNXnet/IP Object Server",
+  [0x07]="KNXnet/IP Remote Configuration and Diagnosis"
+}
+
+knxDibDescriptionTypes = {
+  [0x01]="Device Information",
+  [0x02]="Supp_Svc_families",
+  [0x03]="IP_Config",
+  [0x04]="IP_Cur_Config",
+  [0x05]="IP_Config"
+}
+
+knxMediumTypes = {
+  [0x01]="reserved",
+  [0x02]="KNX TP1",
+  [0x04]="KNX PL110",
+  [0x08]="reserved",
+  [0x10]="KNX RF",
+  [0x20]="KNX IP"
+}
+
+--- Returns a raw knx request
+-- @param service KNX service type of the request
+-- @param ip_address IP address of the sending host
+-- @param port Port where gateways should respond to
+query = function(service, ip_address, port)
+  return string.pack(">BB I2 I2 BB I4 I2",
+    0x06, -- Header length
+    0x10, -- Protocol version
+    service, -- Service type
+    0x000e, -- Total length
+    0x08, -- Structure length
+    0x01, -- Host protocol
+    ipOps.todword(ip_address),
+    port
+  )
+end
+
+--- Parse a KNX address from raw bytes
+-- @param addr Unpacked 2 bytes
+-- @return KNX address in dotted-decimal format
+parseKnxAddress = function(addr)
+  local a = (addr & 0xf000) >> 12
+  local b = (addr & 0x0f00) >>  8
+  local c = addr & 0xff
+  return a..'.'..b..'.'..c
+end
+
+--- Parse a KNX header
+-- @param knxMessage A KNX message packet as a string
+-- @return knx_header_length, or nil on error
+-- @return knx_protocol_version, or error message
+-- @return knx_service_type
+-- @return knx_total_length
+-- @return pos The position just after the header
+parseHeader = function(knxMessage)
+  if #knxMessage < 6 then
+    return nil, "Message too short for KNX header"
+  end
+  local knx_header_length, knx_protocol_version, knx_service_type, knx_total_length, pos = string.unpack(">BB I2 I2", knxMessage)
+
+  -- TODO: Should this be 'or' instead of 'and'?
+  if knx_header_length ~= 0x06 and knx_protocol_version ~= 0x10 and  knx_service_type ~= 0x0204 then
+    return nil, "Unknown KNX header format"
+  end
+
+  return knx_header_length, knx_protocol_version, knx_service_type, knx_total_length, pos
+end
+
+return _ENV