1 /* 2 * Copyright (C) 2019 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License 15 */ 16 17 package android.net.netlink; 18 19 import android.system.OsConstants; 20 import java.nio.ByteBuffer; 21 22 23 /** 24 * struct ndmsg 25 * 26 * see: <linux_src>/include/uapi/linux/neighbour.h 27 * 28 * @hide 29 */ 30 public class StructNdMsg { 31 // Already aligned. 32 public static final int STRUCT_SIZE = 12; 33 34 // Neighbor Cache Entry States 35 public static final short NUD_NONE = 0x00; 36 public static final short NUD_INCOMPLETE = 0x01; 37 public static final short NUD_REACHABLE = 0x02; 38 public static final short NUD_STALE = 0x04; 39 public static final short NUD_DELAY = 0x08; 40 public static final short NUD_PROBE = 0x10; 41 public static final short NUD_FAILED = 0x20; 42 public static final short NUD_NOARP = 0x40; 43 public static final short NUD_PERMANENT = 0x80; 44 stringForNudState(short nudState)45 public static String stringForNudState(short nudState) { 46 switch (nudState) { 47 case NUD_NONE: return "NUD_NONE"; 48 case NUD_INCOMPLETE: return "NUD_INCOMPLETE"; 49 case NUD_REACHABLE: return "NUD_REACHABLE"; 50 case NUD_STALE: return "NUD_STALE"; 51 case NUD_DELAY: return "NUD_DELAY"; 52 case NUD_PROBE: return "NUD_PROBE"; 53 case NUD_FAILED: return "NUD_FAILED"; 54 case NUD_NOARP: return "NUD_NOARP"; 55 case NUD_PERMANENT: return "NUD_PERMANENT"; 56 default: 57 return "unknown NUD state: " + String.valueOf(nudState); 58 } 59 } 60 isNudStateConnected(short nudState)61 public static boolean isNudStateConnected(short nudState) { 62 return ((nudState & (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)) != 0); 63 } 64 isNudStateValid(short nudState)65 public static boolean isNudStateValid(short nudState) { 66 return (isNudStateConnected(nudState) || 67 ((nudState & (NUD_PROBE|NUD_STALE|NUD_DELAY)) != 0)); 68 } 69 70 // Neighbor Cache Entry Flags 71 public static byte NTF_USE = (byte) 0x01; 72 public static byte NTF_SELF = (byte) 0x02; 73 public static byte NTF_MASTER = (byte) 0x04; 74 public static byte NTF_PROXY = (byte) 0x08; 75 public static byte NTF_ROUTER = (byte) 0x80; 76 stringForNudFlags(byte flags)77 public static String stringForNudFlags(byte flags) { 78 final StringBuilder sb = new StringBuilder(); 79 if ((flags & NTF_USE) != 0) { 80 sb.append("NTF_USE"); 81 } 82 if ((flags & NTF_SELF) != 0) { 83 if (sb.length() > 0) { sb.append("|"); } 84 sb.append("NTF_SELF"); 85 } 86 if ((flags & NTF_MASTER) != 0) { 87 if (sb.length() > 0) { sb.append("|"); } 88 sb.append("NTF_MASTER"); 89 } 90 if ((flags & NTF_PROXY) != 0) { 91 if (sb.length() > 0) { sb.append("|"); 92 } 93 sb.append("NTF_PROXY"); } 94 if ((flags & NTF_ROUTER) != 0) { 95 if (sb.length() > 0) { sb.append("|"); } 96 sb.append("NTF_ROUTER"); 97 } 98 return sb.toString(); 99 } 100 hasAvailableSpace(ByteBuffer byteBuffer)101 private static boolean hasAvailableSpace(ByteBuffer byteBuffer) { 102 return byteBuffer != null && byteBuffer.remaining() >= STRUCT_SIZE; 103 } 104 parse(ByteBuffer byteBuffer)105 public static StructNdMsg parse(ByteBuffer byteBuffer) { 106 if (!hasAvailableSpace(byteBuffer)) { return null; } 107 108 // The ByteOrder must have already been set by the caller. In most 109 // cases ByteOrder.nativeOrder() is correct, with the possible 110 // exception of usage within unittests. 111 final StructNdMsg struct = new StructNdMsg(); 112 struct.ndm_family = byteBuffer.get(); 113 final byte pad1 = byteBuffer.get(); 114 final short pad2 = byteBuffer.getShort(); 115 struct.ndm_ifindex = byteBuffer.getInt(); 116 struct.ndm_state = byteBuffer.getShort(); 117 struct.ndm_flags = byteBuffer.get(); 118 struct.ndm_type = byteBuffer.get(); 119 return struct; 120 } 121 122 public byte ndm_family; 123 public int ndm_ifindex; 124 public short ndm_state; 125 public byte ndm_flags; 126 public byte ndm_type; 127 StructNdMsg()128 public StructNdMsg() { 129 ndm_family = (byte) OsConstants.AF_UNSPEC; 130 } 131 pack(ByteBuffer byteBuffer)132 public void pack(ByteBuffer byteBuffer) { 133 // The ByteOrder must have already been set by the caller. In most 134 // cases ByteOrder.nativeOrder() is correct, with the exception 135 // of usage within unittests. 136 byteBuffer.put(ndm_family); 137 byteBuffer.put((byte) 0); // pad1 138 byteBuffer.putShort((short) 0); // pad2 139 byteBuffer.putInt(ndm_ifindex); 140 byteBuffer.putShort(ndm_state); 141 byteBuffer.put(ndm_flags); 142 byteBuffer.put(ndm_type); 143 } 144 nudConnected()145 public boolean nudConnected() { 146 return isNudStateConnected(ndm_state); 147 } 148 nudValid()149 public boolean nudValid() { 150 return isNudStateValid(ndm_state); 151 } 152 153 @Override toString()154 public String toString() { 155 final String stateStr = "" + ndm_state + " (" + stringForNudState(ndm_state) + ")"; 156 final String flagsStr = "" + ndm_flags + " (" + stringForNudFlags(ndm_flags) + ")"; 157 return "StructNdMsg{ " 158 + "family{" + NetlinkConstants.stringForAddressFamily((int) ndm_family) + "}, " 159 + "ifindex{" + ndm_ifindex + "}, " 160 + "state{" + stateStr + "}, " 161 + "flags{" + flagsStr + "}, " 162 + "type{" + ndm_type + "} " 163 + "}"; 164 } 165 } 166