Merge remote-tracking branch 'apache/master' into ZOOKEEPER-3188

README_packaging.md

@@ -65,26 +65,3 @@ The compiled C client can be found here:
 - `zookeeper-client/zookeeper-client-c/target/c/include/zookeeper`   - Native library headers
 
 The same folders gets archived to the `zookeeper-assembly/target/apache-zookeeper-<version>-lib.tar.gz` file, assuming you activated the `full-build` maven profile.
-
-## Package build command (using ant)
-
-**Command to build tarball package:** `ant tar`
-
-`zookeeper-<version>.tar.gz` tarball file structure layout:
-
-- `/bin`              - User executable
-- `/sbin`             - System executable
-- `/libexec`          - Configuration boot trap script
-- `/lib`              - Library dependencies
-- `/docs`             - Documents
-- `/share/zookeeper`  - Project files
-
-
-**Command to build tarball package with native components:** `ant package-native tar`
-
-`zookeeper-<version>-lib.tar.gz` tarball file structure layout:
-
-- `/bin`                 - User executable
-- `/lib`                 - Native libraries
-- `/include/zookeeper`   - Native library headers
-

zookeeper-assembly/src/main/assembly/source-package.xml

@@ -107,9 +107,6 @@
       <outputDirectory>.</outputDirectory>
       <includes>
         <include>pom.xml</include>
-        <include>build.xml</include>
-        <include>ivy.xml</include>
-        <include>ivysettings.xml</include>
         <include>excludeFindBugsFilter.xml</include>
         <include>owaspSuppressions.xml</include>
         <include>checktyle.xml</include>

zookeeper-docs/src/main/resources/markdown/zookeeperAdmin.md

@@ -667,6 +667,15 @@ property, when available, is noted below.
     recommended to set the value to N * **preAllocSize**
     where N >= 2.
 
+* *maxCnxns* :
+    (Java system property: **zookeeper.maxCnxns**)
+    Limits the total number of concurrent connections that can be made to a
+    zookeeper server (per client Port of each server ). This is used to prevent certain
+    classes of DoS attacks. The default is 0 and setting it to 0 entirely removes
+    the limit on total number of concurrent connections.  Accounting for the
+    number of connections for serverCnxnFactory and a secureServerCnxnFactory is done
+    separately, so a peer is allowed to host up to 2*maxCnxns provided they are of appropriate types.
+
 * *maxClientCnxns* :
     (No Java system property)
     Limits the number of concurrent connections (at the socket

zookeeper-server/src/main/java/org/apache/zookeeper/server/ExitCode.java

@@ -48,10 +48,7 @@ public enum ExitCode {
     QUORUM_PACKET_ERROR(13),
 
     /** Unable to bind to the quorum (election) port after multiple retry */
-    UNABLE_TO_BIND_QUORUM_PORT(14),
-
-    /** Failed to shutdown the request processor pipeline gracefully **/
-    SHUTDOWN_UNGRACEFULLY(16);
+    UNABLE_TO_BIND_QUORUM_PORT(14);
 
     private final int value;
 

zookeeper-server/src/main/java/org/apache/zookeeper/server/NIOServerCnxnFactory.java

@@ -273,6 +273,9 @@ private boolean doAccept() {
             try {
                 sc = acceptSocket.accept();
                 accepted = true;
+                if (limitTotalNumberOfCnxns()) {
+                    throw new IOException("Too many connections max allowed is " + maxCnxns);
+                }
                 InetAddress ia = sc.socket().getInetAddress();
                 int cnxncount = getClientCnxnCount(ia);
 
@@ -634,6 +637,7 @@ public void configure(InetSocketAddress addr, int maxcc, int backlog, boolean se
         configureSaslLogin();
 
         maxClientCnxns = maxcc;
+        initMaxCnxns();
         sessionlessCnxnTimeout = Integer.getInteger(ZOOKEEPER_NIO_SESSIONLESS_CNXN_TIMEOUT, 10000);
         // We also use the sessionlessCnxnTimeout as expiring interval for
         // cnxnExpiryQueue. These don't need to be the same, but the expiring

zookeeper-server/src/main/java/org/apache/zookeeper/server/NettyServerCnxnFactory.java

@@ -186,6 +186,11 @@ public void channelActive(ChannelHandlerContext ctx) throws Exception {
             }
 
             final Channel channel = ctx.channel();
+            if (limitTotalNumberOfCnxns()) {
+                ServerMetrics.getMetrics().CONNECTION_REJECTED.add(1);
+                channel.close();
+                return;
+            }
             InetAddress addr = ((InetSocketAddress) channel.remoteAddress()).getAddress();
             if (maxClientCnxns > 0 && getClientCnxnCount(addr) >= maxClientCnxns) {
                 ServerMetrics.getMetrics().CONNECTION_REJECTED.add(1);
@@ -524,6 +529,7 @@ public void closeAll(ServerCnxn.DisconnectReason reason) {
     @Override
     public void configure(InetSocketAddress addr, int maxClientCnxns, int backlog, boolean secure) throws IOException {
         configureSaslLogin();
+        initMaxCnxns();
         localAddress = addr;
         this.maxClientCnxns = maxClientCnxns;
         this.secure = secure;

zookeeper-server/src/main/java/org/apache/zookeeper/server/ServerCnxnFactory.java

@@ -40,6 +40,8 @@
 public abstract class ServerCnxnFactory {
 
     public static final String ZOOKEEPER_SERVER_CNXN_FACTORY = "zookeeper.serverCnxnFactory";
+    private static final String ZOOKEEPER_MAX_CONNECTION = "zookeeper.maxCnxns";
+    public static final int ZOOKEEPER_MAX_CONNECTION_DEFAULT = 0;
 
     private static final Logger LOG = LoggerFactory.getLogger(ServerCnxnFactory.class);
 
@@ -51,6 +53,9 @@ public abstract class ServerCnxnFactory {
      */
     static final ByteBuffer closeConn = ByteBuffer.allocate(0);
 
+    // total number of connections accepted by the ZooKeeper server
+    protected int maxCnxns;
+
     // sessionMap is used by closeSession()
     final ConcurrentHashMap<Long, ServerCnxn> sessionMap = new ConcurrentHashMap<Long, ServerCnxn>();
 
@@ -287,4 +292,40 @@ public static String getUserName() {
         return loginUser;
     }
 
+    /**
+     * Maximum number of connections allowed in the ZooKeeper system
+     */
+    public int getMaxCnxns() {
+        return maxCnxns;
+    }
+
+    protected void initMaxCnxns() {
+        maxCnxns = Integer.getInteger(ZOOKEEPER_MAX_CONNECTION, ZOOKEEPER_MAX_CONNECTION_DEFAULT);
+        if (maxCnxns < 0) {
+            maxCnxns = ZOOKEEPER_MAX_CONNECTION_DEFAULT;
+            LOG.warn("maxCnxns should be greater than or equal to 0, using default vlaue {}.",
+                    ZOOKEEPER_MAX_CONNECTION_DEFAULT);
+        } else if (maxCnxns == ZOOKEEPER_MAX_CONNECTION_DEFAULT) {
+            LOG.warn("maxCnxns is not configured, using default value {}.",
+                    ZOOKEEPER_MAX_CONNECTION_DEFAULT);
+        } else {
+            LOG.info("maxCnxns configured value is {}.", maxCnxns);
+        }
+    }
+
+    /**
+     * Ensure total number of connections are less than the maxCnxns
+     */
+    protected boolean limitTotalNumberOfCnxns() {
+        if (maxCnxns <= 0) {
+            // maxCnxns limit is disabled
+            return false;
+        }
+        int cnxns = getNumAliveConnections();
+        if (cnxns >= maxCnxns) {
+            LOG.error("Too many connections " + cnxns + " - max is " + maxCnxns);
+            return true;
+        }
+        return false;
+    }
 }