335 lines
9.6 KiB
JavaScript
335 lines
9.6 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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"use strict";
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this.EXPORTED_SYMBOLS = [
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"Sntp",
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];
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const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
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// Set to true to see debug messages.
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var DEBUG = false;
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/**
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* Constructor of Sntp.
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*
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* @param dataAvailableCb
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* Callback function gets called when SNTP offset available. Signature
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* is function dataAvailableCb(offsetInMS).
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* @param maxRetryCount
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* Maximum retry count when SNTP failed to connect to server; set to
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* zero to disable the retry.
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* @param refreshPeriodInSecs
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* Refresh period; set to zero to disable refresh.
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* @param timeoutInSecs
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* Timeout value used for connection.
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* @param pools
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* SNTP server lists separated by ';'.
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* @param port
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* SNTP port.
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*/
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this.Sntp = function Sntp(dataAvailableCb, maxRetryCount, refreshPeriodInSecs,
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timeoutInSecs, pools, port) {
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if (dataAvailableCb != null) {
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this._dataAvailableCb = dataAvailableCb;
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}
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if (maxRetryCount != null) {
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this._maxRetryCount = maxRetryCount;
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}
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if (refreshPeriodInSecs != null) {
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this._refreshPeriodInMS = refreshPeriodInSecs * 1000;
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}
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if (timeoutInSecs != null) {
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this._timeoutInMS = timeoutInSecs * 1000;
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}
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if (pools != null && Array.isArray(pools) && pools.length > 0) {
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this._pools = pools;
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}
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if (port != null) {
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this._port = port;
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}
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}
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Sntp.prototype = {
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isAvailable: function isAvailable() {
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return this._cachedOffset != null;
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},
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isExpired: function isExpired() {
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let valid = this._cachedOffset != null && this._cachedTimeInMS != null;
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if (this._refreshPeriodInMS > 0) {
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valid = valid && Date.now() < this._cachedTimeInMS +
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this._refreshPeriodInMS;
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}
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return !valid;
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},
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request: function request() {
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this._request();
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},
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getOffset: function getOffset() {
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return this._cachedOffset;
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},
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/**
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* Indicates the system clock has been changed by [offset]ms so we need to
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* adjust the stored value.
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*/
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updateOffset: function updateOffset(offset) {
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if (this._cachedOffset != null) {
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this._cachedOffset -= offset;
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}
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},
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/**
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* Used to schedule a retry or periodic updates.
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*/
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_schedule: function _schedule(timeInMS) {
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if (this._updateTimer == null) {
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this._updateTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
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}
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this._updateTimer.initWithCallback(this._request.bind(this),
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timeInMS,
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Ci.nsITimer.TYPE_ONE_SHOT);
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debug("Scheduled SNTP request in " + timeInMS + "ms");
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},
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/**
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* Handle the SNTP response.
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*/
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_handleSntp: function _handleSntp(originateTimeInMS, receiveTimeInMS,
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transmitTimeInMS, respondTimeInMS) {
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let clockOffset = Math.floor(((receiveTimeInMS - originateTimeInMS) +
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(transmitTimeInMS - respondTimeInMS)) / 2);
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debug("Clock offset: " + clockOffset);
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// We've succeeded so clear the retry status.
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this._retryCount = 0;
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this._retryPeriodInMS = 0;
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// Cache the latest SNTP offset whenever receiving it.
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this._cachedOffset = clockOffset;
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this._cachedTimeInMS = respondTimeInMS;
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if (this._dataAvailableCb != null) {
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this._dataAvailableCb(clockOffset);
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}
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this._schedule(this._refreshPeriodInMS);
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},
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/**
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* Used for retry SNTP requests.
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*/
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_retry: function _retry() {
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this._retryCount++;
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if (this._retryCount > this._maxRetryCount) {
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debug ("stop retrying SNTP");
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// Clear so we can start with clean status next time we have network.
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this._retryCount = 0;
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this._retryPeriodInMS = 0;
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return;
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}
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this._retryPeriodInMS = Math.max(1000, this._retryPeriodInMS * 2);
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this._schedule(this._retryPeriodInMS);
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},
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/**
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* Request SNTP.
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*/
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_request: function _request() {
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function GetRequest() {
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let NTP_PACKET_SIZE = 48;
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let NTP_MODE_CLIENT = 3;
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let NTP_VERSION = 3;
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let TRANSMIT_TIME_OFFSET = 40;
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// Send the NTP request.
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let requestTimeInMS = Date.now();
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let s = requestTimeInMS / 1000;
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let ms = requestTimeInMS % 1000;
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// NTP time is relative to 1900.
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s += OFFSET_1900_TO_1970;
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let f = ms * 0x100000000 / 1000;
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s = Math.floor(s);
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f = Math.floor(f);
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let buffer = new ArrayBuffer(NTP_PACKET_SIZE);
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let data = new DataView(buffer);
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data.setUint8(0, NTP_MODE_CLIENT | (NTP_VERSION << 3));
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data.setUint32(TRANSMIT_TIME_OFFSET, s, false);
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data.setUint32(TRANSMIT_TIME_OFFSET + 4, f, false);
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return String.fromCharCode.apply(null, new Uint8Array(buffer));
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}
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function SNTPListener() {};
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SNTPListener.prototype = {
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onStartRequest: function onStartRequest(request, context) {
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},
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onStopRequest: function onStopRequest(request, context, status) {
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if (!Components.isSuccessCode(status)) {
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debug ("Connection failed");
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this._requesting = false;
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this._retry();
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}
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}.bind(this),
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onDataAvailable: function onDataAvailable(request, context, inputStream,
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offset, count) {
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function GetTimeStamp(binaryInputStream) {
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let s = binaryInputStream.read32();
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let f = binaryInputStream.read32();
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return Math.floor(
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((s - OFFSET_1900_TO_1970) * 1000) + ((f * 1000) / 0x100000000)
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);
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}
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debug ("Data available: " + count + " bytes");
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try {
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let binaryInputStream = Cc["@mozilla.org/binaryinputstream;1"]
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.createInstance(Ci.nsIBinaryInputStream);
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binaryInputStream.setInputStream(inputStream);
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// We don't need first 24 bytes.
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for (let i = 0; i < 6; i++) {
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binaryInputStream.read32();
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}
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// Offset 24: originate time.
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let originateTimeInMS = GetTimeStamp(binaryInputStream);
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// Offset 32: receive time.
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let receiveTimeInMS = GetTimeStamp(binaryInputStream);
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// Offset 40: transmit time.
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let transmitTimeInMS = GetTimeStamp(binaryInputStream);
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let respondTimeInMS = Date.now();
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this._handleSntp(originateTimeInMS, receiveTimeInMS,
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transmitTimeInMS, respondTimeInMS);
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this._requesting = false;
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} catch (e) {
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debug ("SNTPListener Error: " + e.message);
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this._requesting = false;
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this._retry();
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}
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inputStream.close();
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}.bind(this)
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};
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function SNTPRequester() {}
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SNTPRequester.prototype = {
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onOutputStreamReady: function(stream) {
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try {
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let data = GetRequest();
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let bytes_write = stream.write(data, data.length);
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debug ("SNTP: sent " + bytes_write + " bytes");
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stream.close();
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} catch (e) {
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debug ("SNTPRequester Error: " + e.message);
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this._requesting = false;
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this._retry();
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}
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}.bind(this)
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};
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// Number of seconds between Jan 1, 1900 and Jan 1, 1970.
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// 70 years plus 17 leap days.
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let OFFSET_1900_TO_1970 = ((365 * 70) + 17) * 24 * 60 * 60;
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if (this._requesting) {
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return;
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}
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if (this._pools.length < 1) {
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debug("No server defined");
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return;
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}
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if (this._updateTimer) {
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this._updateTimer.cancel();
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}
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debug ("Making request");
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this._requesting = true;
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let currentThread = Cc["@mozilla.org/thread-manager;1"]
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.getService().currentThread;
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let socketTransportService =
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Cc["@mozilla.org/network/socket-transport-service;1"]
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.getService(Ci.nsISocketTransportService);
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let pump = Cc["@mozilla.org/network/input-stream-pump;1"]
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.createInstance(Ci.nsIInputStreamPump);
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let transport = socketTransportService
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.createTransport(["udp"],
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1,
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this._pools[Math.floor(this._pools.length * Math.random())],
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this._port,
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null);
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transport.setTimeout(Ci.nsISocketTransport.TIMEOUT_CONNECT, this._timeoutInMS);
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transport.setTimeout(Ci.nsISocketTransport.TIMEOUT_READ_WRITE, this._timeoutInMS);
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let outStream = transport.openOutputStream(0, 0, 0)
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.QueryInterface(Ci.nsIAsyncOutputStream);
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let inStream = transport.openInputStream(0, 0, 0);
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pump.init(inStream, -1, -1, 0, 0, false);
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pump.asyncRead(new SNTPListener(), null);
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outStream.asyncWait(new SNTPRequester(), 0, 0, currentThread);
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},
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// Callback function.
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_dataAvailableCb: null,
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// Sntp servers.
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_pools: [
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"0.pool.ntp.org",
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"1.pool.ntp.org",
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"2.pool.ntp.org",
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"3.pool.ntp.org"
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],
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// The SNTP port.
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_port: 123,
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// Maximum retry count allowed when request failed.
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_maxRetryCount: 0,
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// Refresh period.
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_refreshPeriodInMS: 0,
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// Timeout value used for connecting.
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_timeoutInMS: 30 * 1000,
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// Cached SNTP offset.
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_cachedOffset: null,
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// The time point when we cache the offset.
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_cachedTimeInMS: null,
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// Flag to avoid redundant requests.
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_requesting: false,
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// Retry counter.
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_retryCount: 0,
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// Retry time offset (in seconds).
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_retryPeriodInMS: 0,
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// Timer used for retries & daily updates.
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_updateTimer: null
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};
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var debug;
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if (DEBUG) {
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debug = function (s) {
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dump("-*- Sntp: " + s + "\n");
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};
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} else {
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debug = function (s) {};
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}
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