1 /*

     2  * Copyright (c) 2008, 2009, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package sun.nio.ch;

    27 

    28 import java.nio.channels.*;

    29 import java.net.InetAddress;

    30 import java.net.NetworkInterface;

    31 import java.util.*;

    32 

    33 /**

    34  * Simple registry of membership keys for a MulticastChannel.

    35  *

    36  * Instances of this object are not safe by multiple concurrent threads.

    37  */

    38 

    39 class MembershipRegistry {

    40 

    41     // map multicast group to keys

    42     private Map<InetAddress,List<MembershipKeyImpl>> groups = null;

    43 

    44     MembershipRegistry() {

    45     }

    46 

    47     /**

    48      * Checks registry for membership of the group on the given

    49      * network interface.

    50      */

    51     MembershipKey checkMembership(InetAddress group, NetworkInterface interf,

    52                                   InetAddress source)

    53     {

    54         if (groups != null) {

    55             List<MembershipKeyImpl> keys = groups.get(group);

    56             if (keys != null) {

    57                 for (MembershipKeyImpl key: keys) {

    58                     if (key.networkInterface().equals(interf)) {

    59                         // already a member to receive all packets so return

    60                         // existing key or detect conflict

    61                         if (source == null) {

    62                             if (key.sourceAddress() == null)

    63                                 return key;

    64                             throw new IllegalStateException("Already a member to receive all packets");

    65                         }

    66 

    67                         // already have source-specific membership so return key

    68                         // or detect conflict

    69                         if (key.sourceAddress() == null)

    70                             throw new IllegalStateException("Already have source-specific membership");

    71                         if (source.equals(key.sourceAddress()))

    72                             return key;

    73                     }

    74                 }

    75             }

    76         }

    77         return null;

    78     }

    79 

    80     /**

    81      * Add membership to the registry, returning a new membership key.

    82      */

    83     void add(MembershipKeyImpl key) {

    84         InetAddress group = key.group();

    85         List<MembershipKeyImpl> keys;

    86         if (groups == null) {

    87             groups = new HashMap<>();

    88             keys = null;

    89         } else {

    90             keys = groups.get(group);

    91         }

    92         if (keys == null) {

    93             keys = new LinkedList<>();

    94             groups.put(group, keys);

    95         }

    96         keys.add(key);

    97     }

    98 

    99     /**

   100      * Remove a key from the registry

   101      */

   102     void remove(MembershipKeyImpl key) {

   103         InetAddress group = key.group();

   104         List<MembershipKeyImpl> keys = groups.get(group);

   105         if (keys != null) {

   106             Iterator<MembershipKeyImpl> i = keys.iterator();

   107             while (i.hasNext()) {

   108                 if (i.next() == key) {

   109                     i.remove();

   110                     break;

   111                 }

   112             }

   113             if (keys.isEmpty()) {

   114                 groups.remove(group);

   115             }

   116         }

   117     }

   118 

   119     /**

   120      * Invalidate all keys in the registry

   121      */

   122     void invalidateAll() {

   123         if (groups != null) {

   124             for (InetAddress group: groups.keySet()) {

   125                 for (MembershipKeyImpl key: groups.get(group)) {

   126                     key.invalidate();

   127                 }

   128             }

   129         }

   130     }

   131 }