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  */

    24 

    25 package java.net.http;

    26 

    27 import java.io.IOException;

    28 import java.nio.ByteBuffer;

    29 

    30 class SettingsFrame extends Http2Frame {

    31 

    32     int[] parameters;

    33 

    34     public static final int TYPE = 0x4;

    35 

    36     // Flags

    37     public static final int ACK = 0x1;

    38 

    39     @Override

    40     String flagAsString(int flag) {

    41         switch (flag) {

    42         case ACK:

    43             return "ACK";

    44         }

    45         return super.flagAsString(flag);

    46     }

    47 

    48     @Override

    49     public String toString() {

    50         StringBuilder sb = new StringBuilder();

    51         sb.append(super.toString())

    52           .append(" Settings: ");

    53 

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

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

    56                 sb.append(name(i))

    57                   .append("=")

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

    59                   .append(' ');

    60             }

    61         }

    62         return sb.toString();

    63     }

    64 

    65     // Parameters

    66     public static final int HEADER_TABLE_SIZE = 0x1;

    67     public static final int ENABLE_PUSH = 0x2;

    68     public static final int MAX_CONCURRENT_STREAMS = 0x3;

    69     public static final int INITIAL_WINDOW_SIZE = 0x4;

    70     public static final int MAX_FRAME_SIZE = 0x5;

    71     public static final int MAX_HEADER_LIST_SIZE = 0x6;

    72 

    73     private String name(int i) {

    74         switch (i+1) {

    75         case HEADER_TABLE_SIZE:

    76             return "HEADER_TABLE_SIZE";

    77         case ENABLE_PUSH:

    78             return "ENABLE_PUSH";

    79         case MAX_CONCURRENT_STREAMS:

    80             return "MAX_CONCURRENT_STREAMS";

    81         case INITIAL_WINDOW_SIZE:

    82             return "INITIAL_WINDOW_SIZE";

    83         case MAX_FRAME_SIZE:

    84             return "MAX_FRAME_SIZE";

    85         case MAX_HEADER_LIST_SIZE:

    86             return "MAX_HEADER_LIST_SIZE";

    87         }

    88         return "unknown parameter";

    89     }

    90     public static final int MAX_PARAM = 0x6;

    91 

    92     public SettingsFrame() {

    93         type = TYPE;

    94         parameters = new int [MAX_PARAM];

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

    96             parameters[i] = -1;

    97         }

    98     }

    99 

   100     public int getParameter(int paramID) {

   101         if (paramID > MAX_PARAM) {

   102             throw new IllegalArgumentException("illegal parameter");

   103         }

   104         return parameters[paramID-1];

   105     }

   106 

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

   108         if (paramID > MAX_PARAM) {

   109             throw new IllegalArgumentException("illegal parameter");

   110         }

   111         parameters[paramID-1] = value;

   112         return this;

   113     }

   114 

   115     @Override

   116     void readIncomingImpl(ByteBufferConsumer bc) throws IOException {

   117         if (length % 6 != 0) {

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

   119         }

   120         int n = length / 6;

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

   122             int id = bc.getShort();

   123             int val = bc.getInt();

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

   125                 // a known parameter. Ignore otherwise

   126                 parameters[id-1] = val;

   127             }

   128         }

   129     }

   130 

   131     @Override

   132     void computeLength() {

   133         length = 0;

   134         for (int i : parameters) {

   135             if (i != -1) {

   136                 length += 6;

   137             }

   138         }

   139     }

   140 

   141     @Override

   142     void writeOutgoing(ByteBufferGenerator bg) {

   143         super.writeOutgoing(bg);

   144         ByteBuffer buf = bg.getBuffer(length);

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

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

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

   148                 buf.putInt(parameters[i]);

   149             }

   150         }

   151     }

   152 

   153     private static final int K = 1024;

   154 

   155     public static SettingsFrame getDefaultSettings() {

   156         SettingsFrame f = new SettingsFrame();

   157         // TODO: check these values

   158         f.setParameter(ENABLE_PUSH, 1);

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

   160         f.setParameter(MAX_CONCURRENT_STREAMS, 35);

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

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

   163         return f;

   164     }

   165 }