| /* |
| * 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 libcore.io.SizeOf; |
| |
| import java.net.InetAddress; |
| import java.net.UnknownHostException; |
| import java.nio.ByteOrder; |
| import java.nio.ByteBuffer; |
| |
| |
| /** |
| * struct nlattr |
| * |
| * see: <linux_src>/include/uapi/linux/netlink.h |
| * |
| * @hide |
| */ |
| public class StructNlAttr { |
| // Already aligned. |
| public static final int NLA_HEADERLEN = 4; |
| |
| // Return a (length, type) object only, without consuming any bytes in |
| // |byteBuffer| and without copying or interpreting any value bytes. |
| // This is used for scanning over a packed set of struct nlattr's, |
| // looking for instances of a particular type. |
| public static StructNlAttr peek(ByteBuffer byteBuffer) { |
| if (byteBuffer == null || byteBuffer.remaining() < NLA_HEADERLEN) { |
| return null; |
| } |
| final int baseOffset = byteBuffer.position(); |
| |
| final StructNlAttr struct = new StructNlAttr(); |
| struct.nla_len = byteBuffer.getShort(); |
| struct.nla_type = byteBuffer.getShort(); |
| struct.mByteOrder = byteBuffer.order(); |
| |
| byteBuffer.position(baseOffset); |
| if (struct.nla_len < NLA_HEADERLEN) { |
| // Malformed. |
| return null; |
| } |
| return struct; |
| } |
| |
| public static StructNlAttr parse(ByteBuffer byteBuffer) { |
| final StructNlAttr struct = peek(byteBuffer); |
| if (struct == null || byteBuffer.remaining() < struct.getAlignedLength()) { |
| return null; |
| } |
| |
| final int baseOffset = byteBuffer.position(); |
| byteBuffer.position(baseOffset + NLA_HEADERLEN); |
| |
| int valueLen = ((int) struct.nla_len) & 0xffff; |
| valueLen -= NLA_HEADERLEN; |
| if (valueLen > 0) { |
| struct.nla_value = new byte[valueLen]; |
| byteBuffer.get(struct.nla_value, 0, valueLen); |
| byteBuffer.position(baseOffset + struct.getAlignedLength()); |
| } |
| return struct; |
| } |
| |
| public short nla_len; |
| public short nla_type; |
| public byte[] nla_value; |
| public ByteOrder mByteOrder; |
| |
| public StructNlAttr() { |
| mByteOrder = ByteOrder.nativeOrder(); |
| } |
| |
| public int getAlignedLength() { |
| return NetlinkConstants.alignedLengthOf(nla_len); |
| } |
| |
| public ByteBuffer getValueAsByteBuffer() { |
| if (nla_value == null) { return null; } |
| final ByteBuffer byteBuffer = ByteBuffer.wrap(nla_value); |
| byteBuffer.order(mByteOrder); |
| return byteBuffer; |
| } |
| |
| public int getValueAsInt(int defaultValue) { |
| final ByteBuffer byteBuffer = getValueAsByteBuffer(); |
| if (byteBuffer == null || byteBuffer.remaining() != SizeOf.INT) { |
| return defaultValue; |
| } |
| return getValueAsByteBuffer().getInt(); |
| } |
| |
| public InetAddress getValueAsInetAddress() { |
| if (nla_value == null) { return null; } |
| |
| try { |
| return InetAddress.getByAddress(nla_value); |
| } catch (UnknownHostException ignored) { |
| return null; |
| } |
| } |
| |
| public void pack(ByteBuffer byteBuffer) { |
| final int originalPosition = byteBuffer.position(); |
| byteBuffer.putShort(nla_len); |
| byteBuffer.putShort(nla_type); |
| byteBuffer.put(nla_value); |
| byteBuffer.position(originalPosition + getAlignedLength()); |
| } |
| |
| @Override |
| public String toString() { |
| return "StructNlAttr{ " |
| + "nla_len{" + nla_len + "}, " |
| + "nla_type{" + nla_type + "}, " |
| + "nla_value{" + NetlinkConstants.hexify(nla_value) + "}, " |
| + "}"; |
| } |
| } |