michael@0: // -*- Mode: js2; tab-width: 2; indent-tabs-mode: nil; js2-basic-offset: 2; js2-skip-preprocessor-directives: t; -*-
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["SimpleServiceDiscovery"];
michael@0: 
michael@0: const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
michael@0: 
michael@0: Cu.import("resource://gre/modules/Services.jsm");
michael@0: Cu.import("resource://gre/modules/XPCOMUtils.jsm");
michael@0: 
michael@0: function log(msg) {
michael@0:   Services.console.logStringMessage("[SSDP] " + msg);
michael@0: }
michael@0: 
michael@0: XPCOMUtils.defineLazyGetter(this, "converter", function () {
michael@0:   let conv = Cc["@mozilla.org/intl/scriptableunicodeconverter"].createInstance(Ci.nsIScriptableUnicodeConverter);
michael@0:   conv.charset = "utf8";
michael@0:   return conv;
michael@0: });
michael@0: 
michael@0: // Spec information:
michael@0: // https://tools.ietf.org/html/draft-cai-ssdp-v1-03
michael@0: // http://www.dial-multiscreen.org/dial-protocol-specification
michael@0: const SSDP_PORT = 1900;
michael@0: const SSDP_ADDRESS = "239.255.255.250";
michael@0: 
michael@0: const SSDP_DISCOVER_PACKET =
michael@0:   "M-SEARCH * HTTP/1.1\r\n" +
michael@0:   "HOST: " + SSDP_ADDRESS + ":" + SSDP_PORT + "\r\n" +
michael@0:   "MAN: \"ssdp:discover\"\r\n" +
michael@0:   "MX: 2\r\n" +
michael@0:   "ST: %SEARCH_TARGET%\r\n\r\n";
michael@0: 
michael@0: const SSDP_DISCOVER_TIMEOUT = 10000;
michael@0: 
michael@0: /*
michael@0:  * SimpleServiceDiscovery manages any discovered SSDP services. It uses a UDP
michael@0:  * broadcast to locate available services on the local network.
michael@0:  */
michael@0: var SimpleServiceDiscovery = {
michael@0:   _targets: new Map(),
michael@0:   _services: new Map(),
michael@0:   _searchSocket: null,
michael@0:   _searchInterval: 0,
michael@0:   _searchTimestamp: 0,
michael@0:   _searchTimeout: Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer),
michael@0:   _searchRepeat: Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer),
michael@0: 
michael@0:   _forceTrailingSlash: function(aURL) {
michael@0:     // Some devices add the trailing '/' and some don't. Let's make sure
michael@0:     // it's there for consistency.
michael@0:     if (!aURL.endsWith("/")) {
michael@0:       aURL += "/";
michael@0:     }
michael@0:     return aURL;
michael@0:   },
michael@0: 
michael@0:   // nsIUDPSocketListener implementation
michael@0:   onPacketReceived: function(aSocket, aMessage) {
michael@0:     // Listen for responses from specific targets. There could be more than one
michael@0:     // available.
michael@0:     let response = aMessage.data.split("\n");
michael@0:     let location;
michael@0:     let target;
michael@0:     let valid = false;
michael@0:     response.some(function(row) {
michael@0:       let header = row.toUpperCase();
michael@0:       if (header.startsWith("LOCATION")) {
michael@0:         location = row.substr(10).trim();
michael@0:       } else if (header.startsWith("ST")) {
michael@0:         target = row.substr(4).trim();
michael@0:         if (this._targets.has(target)) {
michael@0:           valid = true;
michael@0:         }
michael@0:       }
michael@0: 
michael@0:       if (location && valid) {
michael@0:         location = this._forceTrailingSlash(location);
michael@0: 
michael@0:         // When we find a valid response, package up the service information
michael@0:         // and pass it on.
michael@0:         let service = {
michael@0:           location: location,
michael@0:           target: target
michael@0:         };
michael@0: 
michael@0:         try {
michael@0:           this._processService(service);
michael@0:         } catch (e) {}
michael@0: 
michael@0:         return true;
michael@0:       }
michael@0:       return false;
michael@0:     }.bind(this));
michael@0:   },
michael@0: 
michael@0:   onStopListening: function(aSocket, aStatus) {
michael@0:     // This is fired when the socket is closed expectedly or unexpectedly.
michael@0:     // nsITimer.cancel() is a no-op if the timer is not active.
michael@0:     this._searchTimeout.cancel();
michael@0:     this._searchSocket = null;
michael@0:   },
michael@0: 
michael@0:   // Start a search. Make it continuous by passing an interval (in milliseconds).
michael@0:   // This will stop a current search loop because the timer resets itself.
michael@0:   search: function search(aInterval) {
michael@0:     if (aInterval > 0) {
michael@0:       this._searchInterval = aInterval || 0;
michael@0:       this._searchRepeat.initWithCallback(this._search.bind(this), this._searchInterval, Ci.nsITimer.TYPE_REPEATING_SLACK);
michael@0:     }
michael@0:     this._search();
michael@0:   },
michael@0: 
michael@0:   // Stop the current continuous search
michael@0:   stopSearch: function stopSearch() {
michael@0:     this._searchRepeat.cancel();
michael@0:   },
michael@0: 
michael@0:   _usingLAN: function() {
michael@0:     let network = Cc["@mozilla.org/network/network-link-service;1"].getService(Ci.nsINetworkLinkService);
michael@0:     return (network.linkType == Ci.nsINetworkLinkService.LINK_TYPE_WIFI || network.linkType == Ci.nsINetworkLinkService.LINK_TYPE_ETHERNET);
michael@0:   },
michael@0: 
michael@0:   _search: function _search() {
michael@0:     // If a search is already active, shut it down.
michael@0:     this._searchShutdown();
michael@0: 
michael@0:     // We only search if on local network
michael@0:     if (!this._usingLAN()) {
michael@0:       return;
michael@0:     }
michael@0: 
michael@0:     // Update the timestamp so we can use it to clean out stale services the
michael@0:     // next time we search.
michael@0:     this._searchTimestamp = Date.now();
michael@0: 
michael@0:     // Look for any fixed IP targets. Some routers might be configured to block
michael@0:     // UDP broadcasts, so this is a way to skip discovery.
michael@0:     this._searchFixedTargets();
michael@0: 
michael@0:     // Perform a UDP broadcast to search for SSDP devices
michael@0:     let socket = Cc["@mozilla.org/network/udp-socket;1"].createInstance(Ci.nsIUDPSocket);
michael@0:     try {
michael@0:       socket.init(SSDP_PORT, false);
michael@0:       socket.asyncListen(this);
michael@0:     } catch (e) {
michael@0:       // We were unable to create the broadcast socket. Just return, but don't
michael@0:       // kill the interval timer. This might work next time.
michael@0:       log("failed to start socket: " + e);
michael@0:       return;
michael@0:     }
michael@0: 
michael@0:     this._searchSocket = socket;
michael@0:     this._searchTimeout.initWithCallback(this._searchShutdown.bind(this), SSDP_DISCOVER_TIMEOUT, Ci.nsITimer.TYPE_ONE_SHOT);
michael@0: 
michael@0:     let data = SSDP_DISCOVER_PACKET;
michael@0:     for (let [key, target] of this._targets) {
michael@0:       let msgData = data.replace("%SEARCH_TARGET%", target.target);
michael@0:       try {
michael@0:         let msgRaw = converter.convertToByteArray(msgData);
michael@0:         socket.send(SSDP_ADDRESS, SSDP_PORT, msgRaw, msgRaw.length);
michael@0:       } catch (e) {
michael@0:         log("failed to convert to byte array: " + e);
michael@0:       }
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   _searchFixedTargets: function _searchFixedTargets() {
michael@0:     let fixedTargets = null;
michael@0:     try {
michael@0:       fixedTargets = Services.prefs.getCharPref("browser.casting.fixedTargets");
michael@0:     } catch (e) {}
michael@0: 
michael@0:     if (!fixedTargets) {
michael@0:       return;
michael@0:     }
michael@0: 
michael@0:     fixedTargets = JSON.parse(fixedTargets);
michael@0:     for (let fixedTarget of fixedTargets) {
michael@0:       // Verify we have the right data
michael@0:       if (!"location" in fixedTarget || !"target" in fixedTarget) {
michael@0:         continue;
michael@0:       }
michael@0: 
michael@0:       fixedTarget.location = this._forceTrailingSlash(fixedTarget.location);
michael@0: 
michael@0:       let service = {
michael@0:         location: fixedTarget.location,
michael@0:         target: fixedTarget.target
michael@0:       };
michael@0: 
michael@0:       // We don't assume the fixed target is ready. We still need to ping it.
michael@0:       try {
michael@0:         this._processService(service);
michael@0:       } catch (e) {}
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   // Called when the search timeout is hit. We use it to cleanup the socket and
michael@0:   // perform some post-processing on the services list.
michael@0:   _searchShutdown: function _searchShutdown() {
michael@0:     if (this._searchSocket) {
michael@0:       // This will call onStopListening.
michael@0:       this._searchSocket.close();
michael@0: 
michael@0:       // Clean out any stale services
michael@0:       for (let [key, service] of this._services) {
michael@0:         if (service.lastPing != this._searchTimestamp) {
michael@0:           Services.obs.notifyObservers(null, "ssdp-service-lost", service.location);
michael@0:           this._services.delete(service.location);
michael@0:         }
michael@0:       }
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   registerTarget: function registerTarget(aTarget, aAppFactory) {
michael@0:     // Only add if we don't already know about this target
michael@0:     if (!this._targets.has(aTarget)) {
michael@0:       this._targets.set(aTarget, { target: aTarget, factory: aAppFactory });
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   findAppForService: function findAppForService(aService, aApp) {
michael@0:     if (!aService || !aService.target) {
michael@0:       return null;
michael@0:     }
michael@0: 
michael@0:     // Find the registration for the target
michael@0:     if (this._targets.has(aService.target)) {
michael@0:       return this._targets.get(aService.target).factory(aService, aApp);
michael@0:     }
michael@0:     return null;
michael@0:   },
michael@0: 
michael@0:   findServiceForLocation: function findServiceForLocation(aLocation) {
michael@0:     if (this._services.has(aLocation)) {
michael@0:       return this._services.get(aLocation);
michael@0:     }
michael@0:     return null;
michael@0:   },
michael@0: 
michael@0:   // Returns an array copy of the active services
michael@0:   get services() {
michael@0:     let array = [];
michael@0:     for (let [key, service] of this._services) {
michael@0:       array.push(service);
michael@0:     }
michael@0:     return array;
michael@0:   },
michael@0: 
michael@0:   _processService: function _processService(aService) {
michael@0:     // Use the REST api to request more information about this service
michael@0:     let xhr = Cc["@mozilla.org/xmlextras/xmlhttprequest;1"].createInstance(Ci.nsIXMLHttpRequest);
michael@0:     xhr.open("GET", aService.location, true);
michael@0:     xhr.channel.loadFlags |= Ci.nsIRequest.INHIBIT_CACHING;
michael@0:     xhr.overrideMimeType("text/xml");
michael@0: 
michael@0:     xhr.addEventListener("load", (function() {
michael@0:       if (xhr.status == 200) {
michael@0:         let doc = xhr.responseXML;
michael@0:         aService.appsURL = xhr.getResponseHeader("Application-URL");
michael@0:         if (aService.appsURL && !aService.appsURL.endsWith("/"))
michael@0:           aService.appsURL += "/";
michael@0:         aService.friendlyName = doc.querySelector("friendlyName").textContent;
michael@0:         aService.uuid = doc.querySelector("UDN").textContent;
michael@0:         aService.manufacturer = doc.querySelector("manufacturer").textContent;
michael@0:         aService.modelName = doc.querySelector("modelName").textContent;
michael@0: 
michael@0:         // Only add and notify if we don't already know about this service
michael@0:         if (!this._services.has(aService.location)) {
michael@0:           this._services.set(aService.location, aService);
michael@0:           Services.obs.notifyObservers(null, "ssdp-service-found", aService.location);
michael@0:         }
michael@0: 
michael@0:         // Make sure we remember this service is not stale
michael@0:         this._services.get(aService.location).lastPing = this._searchTimestamp;
michael@0:       }
michael@0:     }).bind(this), false);
michael@0: 
michael@0:     xhr.send(null);
michael@0:   }
michael@0: }