/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.sling.discovery.impl.topology.connector;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.zip.GZIPOutputStream;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.felix.scr.annotations.Activate;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Deactivate;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.Service;
import org.apache.sling.commons.json.JSONException;
import org.apache.sling.discovery.ClusterView;
import org.apache.sling.discovery.impl.Config;
import org.apache.sling.discovery.impl.cluster.ClusterViewService;
import org.apache.sling.discovery.impl.common.heartbeat.HeartbeatHandler;
import org.apache.sling.discovery.impl.topology.announcement.Announcement;
import org.apache.sling.discovery.impl.topology.announcement.AnnouncementFilter;
import org.apache.sling.discovery.impl.topology.announcement.AnnouncementRegistry;
import org.apache.sling.discovery.impl.topology.connector.wl.SubnetWhitelistEntry;
import org.apache.sling.discovery.impl.topology.connector.wl.WhitelistEntry;
import org.apache.sling.discovery.impl.topology.connector.wl.WildcardWhitelistEntry;
import org.osgi.service.component.ComponentContext;
import org.osgi.service.http.HttpService;
import org.osgi.service.http.NamespaceException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Servlet which receives topology announcements at
* /libs/sling/topology/connector*
* without authorization (authorization is handled either via
* hmac-signature with a shared key or via a flexible whitelist)
*/
@SuppressWarnings("serial")
@Component(immediate = true)
@Service(value=TopologyConnectorServlet.class)
public class TopologyConnectorServlet extends HttpServlet {
/**
* prefix under which the topology connector servlet is registered -
* the URL will consist of this prefix + "connector.slingId.json"
*/
private static final String TOPOLOGY_CONNECTOR_PREFIX = "/libs/sling/topology";
private final Logger logger = LoggerFactory.getLogger(this.getClass());
@Reference
private AnnouncementRegistry announcementRegistry;
@Reference
private ClusterViewService clusterViewService;
@Reference
private HeartbeatHandler heartbeatHandler;
@Reference
private HttpService httpService;
@Reference
private Config config;
/**
* This list contains WhitelistEntry (ips/hostnames, cidr, wildcards),
* each filtering some hostname/addresses that are allowed to connect to this servlet.
**/
private final List<WhitelistEntry> whitelist = new ArrayList<WhitelistEntry>();
/** Set of plaintext whitelist entries - for faster lookups **/
private final Set<String> plaintextWhitelist = new HashSet<String>();
private TopologyRequestValidator requestValidator;
@Activate
protected void activate(final ComponentContext context) {
whitelist.clear();
if (!config.isHmacEnabled()) {
String[] whitelistConfig = config.getTopologyConnectorWhitelist();
initWhitelist(whitelistConfig);
}
requestValidator = new TopologyRequestValidator(config);
try {
httpService.registerServlet(TopologyConnectorServlet.TOPOLOGY_CONNECTOR_PREFIX,
this, null, null);
logger.info("activate: connector servlet registered at "+
TopologyConnectorServlet.TOPOLOGY_CONNECTOR_PREFIX);
} catch (ServletException e) {
logger.error("activate: ServletException while registering topology connector servlet: "+e, e);
} catch (NamespaceException e) {
logger.error("activate: NamespaceException while registering topology connector servlet: "+e, e);
}
}
@Deactivate
protected void deactivate() {
httpService.unregister(TOPOLOGY_CONNECTOR_PREFIX);
}
void initWhitelist(String[] whitelistConfig) {
if (whitelistConfig==null) {
return;
}
for (int i = 0; i < whitelistConfig.length; i++) {
String aWhitelistEntry = whitelistConfig[i];
WhitelistEntry whitelistEntry = null;
if (aWhitelistEntry.contains(".") && aWhitelistEntry.contains("/")) {
// then this is a CIDR notation
try{
whitelistEntry = new SubnetWhitelistEntry(aWhitelistEntry);
} catch(Exception e) {
logger.error("activate: wrongly formatted CIDR subnet definition. Expected eg '1.2.3.4/24'. ignoring: "+aWhitelistEntry);
continue;
}
} else if (aWhitelistEntry.contains(".") && aWhitelistEntry.contains(" ")) {
// then this is a IP/subnet-mask notation
try{
final StringTokenizer st = new StringTokenizer(aWhitelistEntry, " ");
final String ip = st.nextToken();
if (st.hasMoreTokens()) {
final String mask = st.nextToken();
if (st.hasMoreTokens()) {
logger.error("activate: wrongly formatted ip subnet definition. Expected '10.1.2.3 255.0.0.0'. Ignoring: "+aWhitelistEntry);
continue;
}
whitelistEntry = new SubnetWhitelistEntry(ip, mask);
}
} catch(Exception e) {
logger.error("activate: wrongly formatted ip subnet definition. Expected '10.1.2.3 255.0.0.0'. Ignoring: "+aWhitelistEntry);
continue;
}
}
if (whitelistEntry==null) {
if (aWhitelistEntry.contains("*") || aWhitelistEntry.contains("?")) {
whitelistEntry = new WildcardWhitelistEntry(aWhitelistEntry);
} else {
plaintextWhitelist.add(aWhitelistEntry);
}
}
logger.info("activate: adding whitelist entry: " + aWhitelistEntry);
if (whitelistEntry!=null) {
whitelist.add(whitelistEntry);
}
}
}
@Override
protected void doDelete(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
if (!isWhitelisted(request)) {
// in theory it would be 403==forbidden, but that would reveal that
// a resource would exist there in the first place
response.sendError(HttpServletResponse.SC_NOT_FOUND);
return;
}
final String[] pathInfo = request.getPathInfo().split("\\.");
final String extension = pathInfo.length==3 ? pathInfo[2] : "";
if (!"json".equals(extension)) {
response.sendError(HttpServletResponse.SC_NOT_FOUND);
return;
}
final String selector = pathInfo.length==3 ? pathInfo[1] : "";
announcementRegistry.unregisterAnnouncement(selector);
}
@Override
protected void doPut(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
if (!isWhitelisted(request)) {
// in theory it would be 403==forbidden, but that would reveal that
// a resource would exist there in the first place
response.sendError(HttpServletResponse.SC_NOT_FOUND);
return;
}
final String[] pathInfo = request.getPathInfo().split("\\.");
final String extension = pathInfo.length==3 ? pathInfo[2] : "";
if (!"json".equals(extension)) {
response.sendError(HttpServletResponse.SC_NOT_FOUND);
return;
}
final String selector = pathInfo.length==3 ? pathInfo[1] : "";
String topologyAnnouncementJSON = requestValidator.decodeMessage(request);
if (logger.isDebugEnabled()) {
logger.debug("doPost: incoming topology announcement is: "
+ topologyAnnouncementJSON);
}
final Announcement incomingTopologyAnnouncement;
try {
incomingTopologyAnnouncement = Announcement
.fromJSON(topologyAnnouncementJSON);
if (!incomingTopologyAnnouncement.getOwnerId().equals(selector)) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST);
return;
}
String slingId = clusterViewService.getSlingId();
if (slingId==null) {
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
logger.info("doPut: no slingId available. Service not ready as expected at the moment.");
return;
}
incomingTopologyAnnouncement.removeInherited(slingId);
final Announcement replyAnnouncement = new Announcement(
slingId);
long backoffInterval = -1;
if (!incomingTopologyAnnouncement.isCorrectVersion()) {
logger.warn("doPost: rejecting an announcement from an incompatible connector protocol version: "
+ incomingTopologyAnnouncement);
response.sendError(HttpServletResponse.SC_BAD_REQUEST);
return;
} else if (clusterViewService.contains(incomingTopologyAnnouncement
.getOwnerId())) {
if (logger.isDebugEnabled()) {
logger.debug("doPost: rejecting an announcement from an instance that is part of my cluster: "
+ incomingTopologyAnnouncement);
}
// marking as 'loop'
replyAnnouncement.setLoop(true);
backoffInterval = config.getBackoffStandbyInterval();
} else if (clusterViewService.containsAny(incomingTopologyAnnouncement
.listInstances())) {
if (logger.isDebugEnabled()) {
logger.debug("doPost: rejecting an announcement as it contains instance(s) that is/are part of my cluster: "
+ incomingTopologyAnnouncement);
}
// marking as 'loop'
replyAnnouncement.setLoop(true);
backoffInterval = config.getBackoffStandbyInterval();
} else {
backoffInterval = announcementRegistry
.registerAnnouncement(incomingTopologyAnnouncement);
if (logger.isDebugEnabled()) {
logger.debug("doPost: backoffInterval after registration: "+backoffInterval);
}
if (backoffInterval==-1) {
if (logger.isDebugEnabled()) {
logger.debug("doPost: rejecting an announcement from an instance that I already see in my topology: "
+ incomingTopologyAnnouncement);
}
// marking as 'loop'
replyAnnouncement.setLoop(true);
backoffInterval = config.getBackoffStandbyInterval();
} else {
// normal, successful case: replying with the part of the topology which this instance sees
final ClusterView clusterView = clusterViewService
.getClusterView();
replyAnnouncement.setLocalCluster(clusterView);
announcementRegistry.addAllExcept(replyAnnouncement, clusterView,
new AnnouncementFilter() {
public boolean accept(final String receivingSlingId, Announcement announcement) {
if (announcement.getPrimaryKey().equals(
incomingTopologyAnnouncement
.getPrimaryKey())) {
return false;
}
return true;
}
});
}
}
if (backoffInterval>0) {
replyAnnouncement.setBackoffInterval(backoffInterval);
if (logger.isDebugEnabled()) {
logger.debug("doPost: backoffInterval for client set to "+replyAnnouncement.getBackoffInterval());
}
}
final String p = requestValidator.encodeMessage(replyAnnouncement.asJSON());
requestValidator.trustMessage(response, request, p);
// gzip the response if the client accepts this
final String acceptEncodingHeader = request.getHeader("Accept-Encoding");
if (acceptEncodingHeader!=null && acceptEncodingHeader.contains("gzip")) {
// tell the client that the content is gzipped:
response.setHeader("Content-Encoding", "gzip");
// then gzip the body
final GZIPOutputStream gzipOut = new GZIPOutputStream(response.getOutputStream());
gzipOut.write(p.getBytes("UTF-8"));
gzipOut.close();
} else {
// otherwise plaintext
final PrintWriter pw = response.getWriter();
pw.print(p);
pw.flush();
}
} catch (JSONException e) {
logger.error("doPost: Got a JSONException: " + e, e);
response.sendError(500);
}
}
/** Checks if the provided request's remote server is whitelisted **/
boolean isWhitelisted(final HttpServletRequest request) {
if (config.isHmacEnabled()) {
final boolean isTrusted = requestValidator.isTrusted(request);
if (!isTrusted) {
logger.info("isWhitelisted: rejecting distrusted " + request.getRemoteAddr()
+ ", " + request.getRemoteHost());
}
return isTrusted;
}
if (plaintextWhitelist.contains(request.getRemoteHost()) ||
plaintextWhitelist.contains(request.getRemoteAddr())) {
return true;
}
for (Iterator<WhitelistEntry> it = whitelist.iterator(); it.hasNext();) {
WhitelistEntry whitelistEntry = it.next();
if (whitelistEntry.accepts(request)) {
return true;
}
}
logger.info("isWhitelisted: rejecting " + request.getRemoteAddr()
+ ", " + request.getRemoteHost());
return false;
}
}