1 /*

     2  * Copyright (c) 2015, 2016, 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 java.net.http;

    27 

    28 import java.io.IOException;

    29 import java.nio.ByteBuffer;

    30 

    31 class SettingsFrame extends Http2Frame {

    32 

    33     int[] parameters;

    34 

    35     public static final int TYPE = 0x4;

    36 

    37     // Flags

    38     public static final int ACK = 0x1;

    39 

    40     @Override

    41     String flagAsString(int flag) {

    42         switch (flag) {

    43         case ACK:

    44             return "ACK";

    45         }

    46         return super.flagAsString(flag);

    47     }

    48 

    49     @Override

    50     public String toString() {

    51         StringBuilder sb = new StringBuilder();

    52         sb.append(super.toString())

    53           .append(" Settings: ");

    54 

    55         for (int i = 0; i < MAX_PARAM; i++) {

    56             if (parameters[i] != -1) {

    57                 sb.append(name(i))

    58                   .append("=")

    59                   .append(Integer.toString(parameters[i]))

    60                   .append(' ');

    61             }

    62         }

    63         return sb.toString();

    64     }

    65 

    66     // Parameters

    67     public static final int HEADER_TABLE_SIZE = 0x1;

    68     public static final int ENABLE_PUSH = 0x2;

    69     public static final int MAX_CONCURRENT_STREAMS = 0x3;

    70     public static final int INITIAL_WINDOW_SIZE = 0x4;

    71     public static final int MAX_FRAME_SIZE = 0x5;

    72     public static final int MAX_HEADER_LIST_SIZE = 0x6;

    73 

    74     private String name(int i) {

    75         switch (i+1) {

    76         case HEADER_TABLE_SIZE:

    77             return "HEADER_TABLE_SIZE";

    78         case ENABLE_PUSH:

    79             return "ENABLE_PUSH";

    80         case MAX_CONCURRENT_STREAMS:

    81             return "MAX_CONCURRENT_STREAMS";

    82         case INITIAL_WINDOW_SIZE:

    83             return "INITIAL_WINDOW_SIZE";

    84         case MAX_FRAME_SIZE:

    85             return "MAX_FRAME_SIZE";

    86         case MAX_HEADER_LIST_SIZE:

    87             return "MAX_HEADER_LIST_SIZE";

    88         }

    89         return "unknown parameter";

    90     }

    91     public static final int MAX_PARAM = 0x6;

    92 

    93     public SettingsFrame() {

    94         type = TYPE;

    95         parameters = new int [MAX_PARAM];

    96         for (int i=0; i < parameters.length; i++) {

    97             parameters[i] = -1;

    98         }

    99     }

   100 

   101     public int getParameter(int paramID) {

   102         if (paramID > MAX_PARAM) {

   103             throw new IllegalArgumentException("illegal parameter");

   104         }

   105         return parameters[paramID-1];

   106     }

   107 

   108     public SettingsFrame setParameter(int paramID, int value) {

   109         if (paramID > MAX_PARAM) {

   110             throw new IllegalArgumentException("illegal parameter");

   111         }

   112         parameters[paramID-1] = value;

   113         return this;

   114     }

   115 

   116     @Override

   117     void readIncomingImpl(ByteBufferConsumer bc) throws IOException {

   118         if (length % 6 != 0) {

   119             throw new IOException("Protocol error: invalid settings frame");

   120         }

   121         int n = length / 6;

   122         for (int i=0; i<n; i++) {

   123             int id = bc.getShort();

   124             int val = bc.getInt();

   125             if (id > 0 || id <= MAX_PARAM) {

   126                 // a known parameter. Ignore otherwise

   127                 parameters[id-1] = val;

   128             }

   129         }

   130     }

   131 

   132     @Override

   133     void computeLength() {

   134         length = 0;

   135         for (int i : parameters) {

   136             if (i != -1) {

   137                 length += 6;

   138             }

   139         }

   140     }

   141 

   142     @Override

   143     void writeOutgoing(ByteBufferGenerator bg) {

   144         super.writeOutgoing(bg);

   145         ByteBuffer buf = bg.getBuffer(length);

   146         for (int i = 0; i < MAX_PARAM; i++) {

   147             if (parameters[i] != -1) {

   148                 buf.putShort((short)(i+1));

   149                 buf.putInt(parameters[i]);

   150             }

   151         }

   152     }

   153 

   154     private static final int K = 1024;

   155 

   156     public static SettingsFrame getDefaultSettings() {

   157         SettingsFrame f = new SettingsFrame();

   158         // TODO: check these values

   159         f.setParameter(ENABLE_PUSH, 1);

   160         f.setParameter(HEADER_TABLE_SIZE, 4 * K);

   161         f.setParameter(MAX_CONCURRENT_STREAMS, 35);

   162         f.setParameter(INITIAL_WINDOW_SIZE, 16 * K);

   163         f.setParameter(MAX_FRAME_SIZE, 16 * K);

   164         return f;

   165     }

   166 }