content: /*
   * Copyright (C) 2017 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 static android.net.netlink.StructNlMsgHdr.NLM_F_ACK;
  import static android.net.netlink.StructNlMsgHdr.NLM_F_REPLACE;
  import static android.net.netlink.StructNlMsgHdr.NLM_F_REQUEST;
  
  import static java.nio.ByteOrder.BIG_ENDIAN;
  
  import android.system.OsConstants;
  
  import java.net.Inet4Address;
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  
  
  /**
   * A NetlinkMessage subclass for netlink conntrack messages.
   *
   * see also: &lt;linux_src&gt;/include/uapi/linux/netfilter/nfnetlink_conntrack.h
   *
   * @hide
   */
  public class ConntrackMessage extends NetlinkMessage {
      public static final int STRUCT_SIZE = StructNlMsgHdr.STRUCT_SIZE + StructNfGenMsg.STRUCT_SIZE;
  
      public static final short NFNL_SUBSYS_CTNETLINK = 1;
      public static final short IPCTNL_MSG_CT_NEW = 0;
  
      // enum ctattr_type
      public static final short CTA_TUPLE_ORIG  = 1;
      public static final short CTA_TUPLE_REPLY = 2;
      public static final short CTA_TIMEOUT     = 7;
  
      // enum ctattr_tuple
      public static final short CTA_TUPLE_IP    = 1;
      public static final short CTA_TUPLE_PROTO = 2;
  
      // enum ctattr_ip
      public static final short CTA_IP_V4_SRC = 1;
      public static final short CTA_IP_V4_DST = 2;
  
      // enum ctattr_l4proto
      public static final short CTA_PROTO_NUM      = 1;
      public static final short CTA_PROTO_SRC_PORT = 2;
      public static final short CTA_PROTO_DST_PORT = 3;
  
      public static byte[] newIPv4TimeoutUpdateRequest(
              int proto, Inet4Address src, int sport, Inet4Address dst, int dport, int timeoutSec) {
          // *** STYLE WARNING ***
          //
          // Code below this point uses extra block indentation to highlight the
          // packing of nested tuple netlink attribute types.
          final StructNlAttr ctaTupleOrig = new StructNlAttr(CTA_TUPLE_ORIG,
                  new StructNlAttr(CTA_TUPLE_IP,
                          new StructNlAttr(CTA_IP_V4_SRC, src),
                          new StructNlAttr(CTA_IP_V4_DST, dst)),
                  new StructNlAttr(CTA_TUPLE_PROTO,
                          new StructNlAttr(CTA_PROTO_NUM, (byte) proto),
                          new StructNlAttr(CTA_PROTO_SRC_PORT, (short) sport, BIG_ENDIAN),
                          new StructNlAttr(CTA_PROTO_DST_PORT, (short) dport, BIG_ENDIAN)));
  
          final StructNlAttr ctaTimeout = new StructNlAttr(CTA_TIMEOUT, timeoutSec, BIG_ENDIAN);
  
          final int payloadLength = ctaTupleOrig.getAlignedLength() + ctaTimeout.getAlignedLength();
          final byte[] bytes = new byte[STRUCT_SIZE + payloadLength];
          final ByteBuffer byteBuffer = ByteBuffer.wrap(bytes);
          byteBuffer.order(ByteOrder.nativeOrder());
  
          final ConntrackMessage ctmsg = new ConntrackMessage();
          ctmsg.mHeader.nlmsg_len = bytes.length;
          ctmsg.mHeader.nlmsg_type = (NFNL_SUBSYS_CTNETLINK << 8) | IPCTNL_MSG_CT_NEW;
          ctmsg.mHeader.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_REPLACE;
          ctmsg.mHeader.nlmsg_seq = 1;
          ctmsg.pack(byteBuffer);
  
          ctaTupleOrig.pack(byteBuffer);
          ctaTimeout.pack(byteBuffer);
  
          return bytes;
      }
  
      protected StructNfGenMsg mNfGenMsg;
  
      private ConntrackMessage() {
          super(new StructNlMsgHdr());
          mNfGenMsg = new StructNfGenMsg((byte) OsConstants.AF_INET);
      }
  
      public void pack(ByteBuffer byteBuffer) {
          mHeader.pack(byteBuffer);
          mNfGenMsg.pack(byteBuffer);
      }
  }
  