ConntrackMessage.java revision 7a65bc62fbe0391f88834ab27b32033d6b957c8b 
1/*
2 * Copyright (C) 2017 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
17package android.net.netlink;
18
19import static android.net.netlink.NetlinkConstants.alignedLengthOf;
20import static android.net.netlink.StructNlAttr.makeNestedType;
21import static android.net.netlink.StructNlAttr.NLA_HEADERLEN;
22import static android.net.netlink.StructNlMsgHdr.NLM_F_ACK;
23import static android.net.netlink.StructNlMsgHdr.NLM_F_DUMP;
24import static android.net.netlink.StructNlMsgHdr.NLM_F_REPLACE;
25import static android.net.netlink.StructNlMsgHdr.NLM_F_REQUEST;
26import static android.net.util.NetworkConstants.IPV4_ADDR_LEN;
27import static java.nio.ByteOrder.BIG_ENDIAN;
28
29import android.system.OsConstants;
30import android.util.Log;
31import libcore.io.SizeOf;
32
33import java.net.Inet4Address;
34import java.net.Inet6Address;
35import java.net.InetAddress;
36import java.nio.ByteBuffer;
37import java.nio.ByteOrder;
38
39
40/**
41 * A NetlinkMessage subclass for netlink conntrack messages.
42 *
43 * see also: <linux_src>/include/uapi/linux/netfilter/nfnetlink_conntrack.h
44 *
45 * @hide
46 */
47public class ConntrackMessage extends NetlinkMessage {
48    public static final int STRUCT_SIZE = StructNlMsgHdr.STRUCT_SIZE + StructNfGenMsg.STRUCT_SIZE;
49
50    public static final short NFNL_SUBSYS_CTNETLINK = 1;
51    public static final short IPCTNL_MSG_CT_NEW = 0;
52
53    // enum ctattr_type
54    public static final short CTA_TUPLE_ORIG  = 1;
55    public static final short CTA_TUPLE_REPLY = 2;
56    public static final short CTA_TIMEOUT     = 7;
57
58    // enum ctattr_tuple
59    public static final short CTA_TUPLE_IP    = 1;
60    public static final short CTA_TUPLE_PROTO = 2;
61
62    // enum ctattr_ip
63    public static final short CTA_IP_V4_SRC = 1;
64    public static final short CTA_IP_V4_DST = 2;
65
66    // enum ctattr_l4proto
67    public static final short CTA_PROTO_NUM      = 1;
68    public static final short CTA_PROTO_SRC_PORT = 2;
69    public static final short CTA_PROTO_DST_PORT = 3;
70
71    public static byte[] newIPv4TimeoutUpdateRequest(
72            int proto, Inet4Address src, int sport, Inet4Address dst, int dport, int timeoutSec) {
73        // *** STYLE WARNING ***
74        //
75        // Code below this point uses extra block indentation to highlight the
76        // packing of nested tuple netlink attribute types.
77        final StructNlAttr ctaTupleOrig = new StructNlAttr(CTA_TUPLE_ORIG,
78                new StructNlAttr(CTA_TUPLE_IP,
79                        new StructNlAttr(CTA_IP_V4_SRC, src),
80                        new StructNlAttr(CTA_IP_V4_DST, dst)),
81                new StructNlAttr(CTA_TUPLE_PROTO,
82                        new StructNlAttr(CTA_PROTO_NUM, (byte) proto),
83                        new StructNlAttr(CTA_PROTO_SRC_PORT, (short) sport, BIG_ENDIAN),
84                        new StructNlAttr(CTA_PROTO_DST_PORT, (short) dport, BIG_ENDIAN)));
85
86        final StructNlAttr ctaTimeout = new StructNlAttr(CTA_TIMEOUT, timeoutSec, BIG_ENDIAN);
87
88        final int payloadLength = ctaTupleOrig.getAlignedLength() + ctaTimeout.getAlignedLength();
89        final byte[] bytes = new byte[STRUCT_SIZE + payloadLength];
90        final ByteBuffer byteBuffer = ByteBuffer.wrap(bytes);
91        byteBuffer.order(ByteOrder.nativeOrder());
92
93        final ConntrackMessage ctmsg = new ConntrackMessage();
94        ctmsg.mHeader.nlmsg_len = bytes.length;
95        ctmsg.mHeader.nlmsg_type = (NFNL_SUBSYS_CTNETLINK << 8) | IPCTNL_MSG_CT_NEW;
96        ctmsg.mHeader.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_REPLACE;
97        ctmsg.mHeader.nlmsg_seq = 1;
98        ctmsg.pack(byteBuffer);
99
100        ctaTupleOrig.pack(byteBuffer);
101        ctaTimeout.pack(byteBuffer);
102
103        return bytes;
104    }
105
106    protected StructNfGenMsg mNfGenMsg;
107
108    private ConntrackMessage() {
109        super(new StructNlMsgHdr());
110        mNfGenMsg = new StructNfGenMsg((byte) OsConstants.AF_INET);
111    }
112
113    public void pack(ByteBuffer byteBuffer) {
114        mHeader.pack(byteBuffer);
115        mNfGenMsg.pack(byteBuffer);
116    }
117}
118