1 /*
2 * Copyright 2020 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * https://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, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.handler.pcap;
17
18 import io.netty.buffer.ByteBuf;
19
20 final class PcapHeaders {
21
22 /**
23 * Pcap Global Header built from:
24 * <ol>
25 * <li> magic_number </li>
26 * <li> version_major </li>
27 * <li> version_minor </li>
28 * <li> thiszone </li>
29 * <li> sigfigs </li>
30 * <li> snaplen </li>
31 * <li> network </li>
32 * </ol>
33 */
34 private static final byte[] GLOBAL_HEADER = new byte[]{-95, -78, -61, -44, 0, 2, 0, 4, 0, 0,
35 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 0, 0, 0, 1};
36
37 private PcapHeaders() {
38 // Prevent outside initialization
39 }
40
41 /**
42 * Write Pcap Global Header
43 *
44 * @param byteBuf byteBuf where we'll write header data
45 */
46 public static void writeGlobalHeader(ByteBuf byteBuf) {
47 byteBuf.writeBytes(GLOBAL_HEADER);
48 }
49
50 /**
51 * Write Pcap Packet Header
52 *
53 * @param byteBuf ByteBuf where we'll write header data
54 * @param ts_sec timestamp seconds
55 * @param ts_usec timestamp microseconds
56 * @param incl_len number of octets of packet saved in file
57 * @param orig_len actual length of packet
58 */
59 static void writePacketHeader(ByteBuf byteBuf, int ts_sec, int ts_usec, int incl_len, int orig_len) {
60 byteBuf.writeInt(ts_sec);
61 byteBuf.writeInt(ts_usec);
62 byteBuf.writeInt(incl_len);
63 byteBuf.writeInt(orig_len);
64 }
65 }