content: /*
   * Copyright (C) 2015 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package android.net.netlink;
  
  import android.net.netlink.NetlinkConstants;
  import android.system.OsConstants;
  import java.nio.ByteBuffer;
  
  
  /**
   * struct ndmsg
   *
   * see: &lt;linux_src&gt;/include/uapi/linux/neighbour.h
   *
   * @hide
   */
  public class StructNdMsg {
      // Already aligned.
      public static final int STRUCT_SIZE = 12;
  
      // Neighbor Cache Entry States
      public static final short NUD_NONE        = 0x00;
      public static final short NUD_INCOMPLETE  = 0x01;
      public static final short NUD_REACHABLE   = 0x02;
      public static final short NUD_STALE       = 0x04;
      public static final short NUD_DELAY       = 0x08;
      public static final short NUD_PROBE       = 0x10;
      public static final short NUD_FAILED      = 0x20;
      public static final short NUD_NOARP       = 0x40;
      public static final short NUD_PERMANENT   = 0x80;
  
      public static String stringForNudState(short nudState) {
          switch (nudState) {
              case NUD_NONE: return "NUD_NONE";
              case NUD_INCOMPLETE: return "NUD_INCOMPLETE";
              case NUD_REACHABLE: return "NUD_REACHABLE";
              case NUD_STALE: return "NUD_STALE";
              case NUD_DELAY: return "NUD_DELAY";
              case NUD_PROBE: return "NUD_PROBE";
              case NUD_FAILED: return "NUD_FAILED";
              case NUD_NOARP: return "NUD_NOARP";
              case NUD_PERMANENT: return "NUD_PERMANENT";
              default:
                  return "unknown NUD state: " + String.valueOf(nudState);
          }
      }
  
      public static boolean isNudStateConnected(short nudState) {
          return ((nudState & (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)) != 0);
      }
  
      public static boolean isNudStateValid(short nudState) {
          return (isNudStateConnected(nudState) ||
                  ((nudState & (NUD_PROBE|NUD_STALE|NUD_DELAY)) != 0));
      }
  
      // Neighbor Cache Entry Flags
      public static byte NTF_USE       = (byte) 0x01;
      public static byte NTF_SELF      = (byte) 0x02;
      public static byte NTF_MASTER    = (byte) 0x04;
      public static byte NTF_PROXY     = (byte) 0x08;
      public static byte NTF_ROUTER    = (byte) 0x80;
  
      public static String stringForNudFlags(byte flags) {
          final StringBuilder sb = new StringBuilder();
          if ((flags & NTF_USE) != 0) {
              sb.append("NTF_USE");
          }
          if ((flags & NTF_SELF) != 0) {
              if (sb.length() > 0) { sb.append("|"); }
              sb.append("NTF_SELF");
          }
          if ((flags & NTF_MASTER) != 0) {
              if (sb.length() > 0) { sb.append("|"); }
              sb.append("NTF_MASTER");
          }
          if ((flags & NTF_PROXY) != 0) {
              if (sb.length() > 0) { sb.append("|");
          }
              sb.append("NTF_PROXY"); }
          if ((flags & NTF_ROUTER) != 0) {
              if (sb.length() > 0) { sb.append("|"); }
              sb.append("NTF_ROUTER");
          }
          return sb.toString();
      }
  
      private static boolean hasAvailableSpace(ByteBuffer byteBuffer) {
          return byteBuffer != null && byteBuffer.remaining() >= STRUCT_SIZE;
      }
  
      public static StructNdMsg parse(ByteBuffer byteBuffer) {
          if (!hasAvailableSpace(byteBuffer)) { return null; }
  
          // The ByteOrder must have already been set by the caller.  In most
          // cases ByteOrder.nativeOrder() is correct, with the possible
          // exception of usage within unittests.
          final StructNdMsg struct = new StructNdMsg();
          struct.ndm_family = byteBuffer.get();
          final byte pad1 = byteBuffer.get();
          final short pad2 = byteBuffer.getShort();
          struct.ndm_ifindex = byteBuffer.getInt();
          struct.ndm_state = byteBuffer.getShort();
          struct.ndm_flags = byteBuffer.get();
          struct.ndm_type = byteBuffer.get();
          return struct;
      }
  
      public byte ndm_family;
      public int ndm_ifindex;
      public short ndm_state;
      public byte ndm_flags;
      public byte ndm_type;
  
      public StructNdMsg() {
          ndm_family = (byte) OsConstants.AF_UNSPEC;
      }
  
      public void pack(ByteBuffer byteBuffer) {
          // The ByteOrder must have already been set by the caller.  In most
          // cases ByteOrder.nativeOrder() is correct, with the exception
          // of usage within unittests.
          byteBuffer.put(ndm_family);
          byteBuffer.put((byte) 0);         // pad1
          byteBuffer.putShort((short) 0);   // pad2
          byteBuffer.putInt(ndm_ifindex);
          byteBuffer.putShort(ndm_state);
          byteBuffer.put(ndm_flags);
          byteBuffer.put(ndm_type);
      }
  
      public boolean nudConnected() {
          return isNudStateConnected(ndm_state);
      }
  
      public boolean nudValid() {
          return isNudStateValid(ndm_state);
      }
  
      @Override
      public String toString() {
          final String stateStr = "" + ndm_state + " (" + stringForNudState(ndm_state) + ")";
          final String flagsStr = "" + ndm_flags + " (" + stringForNudFlags(ndm_flags) + ")";
          return "StructNdMsg{ "
                  + "family{" + NetlinkConstants.stringForAddressFamily((int) ndm_family) + "}, "
                  + "ifindex{" + ndm_ifindex + "}, "
                  + "state{" + stateStr + "}, "
                  + "flags{" + flagsStr + "}, "
                  + "type{" + ndm_type + "} "
                  + "}";
      }
  }
  