Timeserver: filter gateway with ms timestamp
This commit is contained in:
parent
f7aede199d
commit
d4ddb4811f
@ -153,7 +153,7 @@
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"y": 200,
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"wires": [
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[
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"f868bce2.dde67"
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"831ab883.d6a238"
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]
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]
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},
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@ -182,37 +182,12 @@
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"y": 40,
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"wires": []
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},
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{
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"id": "f868bce2.dde67",
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"type": "switch",
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"z": "449c1517.e25f4c",
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"name": "Timechecker",
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"property": "payload.metadata.gateways[0].time",
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"propertyType": "msg",
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"rules": [
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{
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"t": "lte",
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"v": "payload.metadata.time",
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"vt": "msg"
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}
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],
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"checkall": "true",
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"repair": false,
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"outputs": 1,
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"x": 590,
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"y": 200,
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"wires": [
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[
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"831ab883.d6a238"
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]
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]
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},
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{
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"id": "831ab883.d6a238",
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"type": "function",
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"z": "449c1517.e25f4c",
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"name": "Generate Time Answer",
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"func": "/* LoRaWAN Timeserver\n\nconstruct 6 byte timesync_answer from gateway timestamp and node's time_sync_req\n\nbyte meaning\n0 sequence number (taken from node's time_sync_req)\n1..4 current second (from epoch time 1970)\n5 1/250ths fractions of current second\n\n*/\n\nfunction timecompare(a, b) {\n \n const timeA = a.time;\n const timeB = b.time;\n\n let comparison = 0;\n if (timeA > timeB) {\n comparison = 1;\n } else if (timeA < timeB) {\n comparison = -1;\n }\n return comparison;\n}\n\nlet confidence = 2000; // max millisecond diff gateway time to server time\n\nvar deviceMsg = { payload: msg.payload.dev_id };\nvar gateways = msg.payload.metadata.gateways;\nvar gateway_time = gateways.map(gw => {\n return {\n time: new Date(gw.time),\n eui: gw.gtw_id,\n }\n });\nvar server_time = new Date(msg.payload.metadata.time);\n\n// validate all gateway timestamps against lorawan server_time (which is assumed to be recent)\nvar gw_timestamps = gateway_time.filter(function (element) {\n return ((element.time > (server_time - confidence) && element.time <= server_time));\n});\n\n// if no timestamp left, we have no valid one and exit\nif (gw_timestamps.length === 0) return [\"n/a\", \"n/a\", deviceMsg, 0xff];\n\n// sort time array in ascending order to find most recent timestamp for time answer\ngw_timestamps.sort(timecompare);\n\nvar timestamp = gw_timestamps[0].time;\nvar eui = gw_timestamps[0].eui;\nvar offset = server_time - timestamp;\n\nvar seconds = Math.floor(timestamp/1000);\nvar fractions = (timestamp % 1000) / 4;\nvar seqno = msg.payload.payload_raw[0];\n\nlet buf = new ArrayBuffer(6);\nnew DataView(buf).setUint8(0, seqno);\nnew DataView(buf).setUint32(1, seconds);\nnew DataView(buf).setUint8(5, fractions);\n\nmsg.payload = new Buffer(new Uint8Array(buf));\nvar euiMsg = { payload: eui };\nvar offsetMsg = { payload: offset };\n\nreturn [euiMsg, offsetMsg, deviceMsg, msg];",
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"func": "/* LoRaWAN Timeserver\n\nconstruct 6 byte timesync_answer from gateway timestamp and node's time_sync_req\n\nbyte meaning\n0 sequence number (taken from node's time_sync_req)\n1..4 current second (from epoch time 1970)\n5 1/250ths fractions of current second\n\n*/\n\nfunction timecompare(a, b) {\n \n const timeA = a.time;\n const timeB = b.time;\n\n let comparison = 0;\n if (timeA > timeB) {\n comparison = 1;\n } else if (timeA < timeB) {\n comparison = -1;\n }\n return comparison;\n}\n\nlet confidence = 2000; // max millisecond diff gateway time to server time\n\nvar deviceMsg = { payload: msg.payload.dev_id };\nvar gateway_list = msg.payload.metadata.gateways;\n\n// filter all gateway timestamps that have milliseconds part (which we assume have a \".\")\nvar gateways = gateway_list.filter(function (element) {\n return (element.time.includes(\".\"));\n});\n\nvar gateway_time = gateways.map(gw => {\n return {\n time: new Date(gw.time),\n eui: gw.gtw_id,\n }\n });\nvar server_time = new Date(msg.payload.metadata.time);\n\n// validate all gateway timestamps against lorawan server_time (which is assumed to be recent)\nvar gw_timestamps = gateway_time.filter(function (element) {\n return ((element.time > (server_time - confidence) && element.time <= server_time));\n});\n\n// if no timestamp left, we have no valid one and exit\nif (gw_timestamps.length === 0) return [\"n/a\", \"n/a\", deviceMsg, 0xff];\n\n// sort time array in ascending order to find most recent timestamp for time answer\ngw_timestamps.sort(timecompare);\n\nvar timestamp = gw_timestamps[0].time;\nvar eui = gw_timestamps[0].eui;\nvar offset = server_time - timestamp;\n\nvar seconds = Math.floor(timestamp/1000);\nvar fractions = (timestamp % 1000) / 4;\nvar seqno = msg.payload.payload_raw[0];\n\nlet buf = new ArrayBuffer(6);\nnew DataView(buf).setUint8(0, seqno);\nnew DataView(buf).setUint32(1, seconds);\nnew DataView(buf).setUint8(5, fractions);\n\nmsg.payload = new Buffer(new Uint8Array(buf));\nvar euiMsg = { payload: eui };\nvar offsetMsg = { payload: offset };\n\nreturn [euiMsg, offsetMsg, deviceMsg, msg];",
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"outputs": 4,
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"noerr": 0,
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"x": 360,
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@ -251,7 +226,7 @@
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"tostatus": true,
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"complete": "payload",
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"x": 700,
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"y": 280,
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"y": 240,
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"wires": [],
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"icon": "node-red/bridge.png"
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},
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@ -268,7 +243,7 @@
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"format": "{{msg.payload}}",
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"layout": "col-center",
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"x": 810,
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"y": 336,
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"y": 300,
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"wires": []
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},
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{
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@ -294,7 +269,7 @@
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"seg1": "",
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"seg2": "",
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"x": 710,
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"y": 416,
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"y": 380,
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"wires": []
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},
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{
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@ -310,7 +285,7 @@
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"format": "{{msg.payload}}",
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"layout": "col-center",
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"x": 700,
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"y": 376,
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"y": 340,
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"wires": []
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},
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{
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@ -322,7 +297,7 @@
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"outputs": 1,
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"noerr": 0,
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"x": 670,
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"y": 336,
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"y": 300,
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"wires": [
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[
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"8712a5ac.ed18e8"
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@ -342,7 +317,7 @@
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"format": "{{msg.payload}}",
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"layout": "col-center",
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"x": 700,
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"y": 456,
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"y": 420,
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"wires": []
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},
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{
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