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 EthernetPacket {
21
22 /**
23 * MAC Address: 00:00:5E:00:53:00
24 */
25 private static final byte[] DUMMY_SOURCE_MAC_ADDRESS = new byte[]{0, 0, 94, 0, 83, 0};
26
27 /**
28 * MAC Address: 00:00:5E:00:53:FF
29 */
30 private static final byte[] DUMMY_DESTINATION_MAC_ADDRESS = new byte[]{0, 0, 94, 0, 83, -1};
31
32 /**
33 * IPv4
34 */
35 private static final int V4 = 0x0800;
36
37 /**
38 * IPv6
39 */
40 private static final int V6 = 0x86dd;
41
42 private EthernetPacket() {
43 // Prevent outside initialization
44 }
45
46 /**
47 * Write IPv4 Ethernet Packet. It uses a dummy MAC address for both source and destination.
48 *
49 * @param byteBuf ByteBuf where Ethernet Packet data will be set
50 * @param payload Payload of IPv4
51 */
52 static void writeIPv4(ByteBuf byteBuf, ByteBuf payload) {
53 writePacket(byteBuf, payload, DUMMY_SOURCE_MAC_ADDRESS, DUMMY_DESTINATION_MAC_ADDRESS, V4);
54 }
55
56 /**
57 * Write IPv6 Ethernet Packet. It uses a dummy MAC address for both source and destination.
58 *
59 * @param byteBuf ByteBuf where Ethernet Packet data will be set
60 * @param payload Payload of IPv6
61 */
62 static void writeIPv6(ByteBuf byteBuf, ByteBuf payload) {
63 writePacket(byteBuf, payload, DUMMY_SOURCE_MAC_ADDRESS, DUMMY_DESTINATION_MAC_ADDRESS, V6);
64 }
65
66 /**
67 * Write IPv6 Ethernet Packet
68 *
69 * @param byteBuf ByteBuf where Ethernet Packet data will be set
70 * @param payload Payload of IPv6
71 * @param srcAddress Source MAC Address
72 * @param dstAddress Destination MAC Address
73 * @param type Type of Frame
74 */
75 private static void writePacket(ByteBuf byteBuf, ByteBuf payload, byte[] srcAddress, byte[] dstAddress, int type) {
76 byteBuf.writeBytes(dstAddress); // Destination MAC Address
77 byteBuf.writeBytes(srcAddress); // Source MAC Address
78 byteBuf.writeShort(type); // Frame Type (IPv4 or IPv6)
79 byteBuf.writeBytes(payload); // Payload of L3
80 }
81 }