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 final static 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 setLength() {
 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 }