1 package org.metricshub.ipmi.core.coding.rmcp;
2
3 /*-
4 * ╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲
5 * IPMI Java Client
6 * ჻჻჻჻჻჻
7 * Copyright 2023 Verax Systems, MetricsHub
8 * ჻჻჻჻჻჻
9 * This program is free software: you can redistribute it and/or modify
10 * it under the terms of the GNU Lesser General Public License as
11 * published by the Free Software Foundation, either version 3 of the
12 * License, or (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Lesser Public License for more details.
18 *
19 * You should have received a copy of the GNU General Lesser Public
20 * License along with this program. If not, see
21 * <http://www.gnu.org/licenses/lgpl-3.0.html>.
22 * ╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱
23 */
24
25 import org.metricshub.ipmi.core.common.TypeConverter;
26
27 /**
28 * Decodes RMCP packet from raw data.
29 */
30 public final class RmcpDecoder {
31
32 private RmcpDecoder() {
33 }
34
35 /**
36 * Decodes the RMCP packet from raw data.
37 * @param rawMessage
38 * - packet data in a byte form
39 * @return RMCPMessage
40 * @throws IllegalArgumentException
41 * - occurs when message is too short or contains invalid data
42 */
43 public static RmcpMessage decode(byte[] rawMessage) {
44 RmcpMessage message = new RmcpMessage();
45
46 if (rawMessage.length < 4) {
47 throw new IllegalArgumentException("Message is corrupted");
48 }
49
50 message.setVersion(decodeVersion(rawMessage[0]));
51
52 // byte 1 is reserved
53
54 message.setSequenceNumber(decodeSequenceNumber(rawMessage[2]));
55
56 message.setClassOfMessage(decodeClassOfMessage(rawMessage[3]));
57
58 message.setData(decodeData(rawMessage));
59
60 return message;
61 }
62
63 private static RmcpVersion decodeVersion(byte version) {
64 if (version == RmcpConstants.RMCP_V1_0) {
65 return RmcpVersion.RMCP1_0;
66 }
67
68 throw new IllegalArgumentException("Illegal RMCP version");
69 }
70
71 private static int decodeSequenceNumber(byte sequenceNumber) {
72 return TypeConverter.byteToInt(sequenceNumber);
73 }
74
75 private static RmcpClassOfMessage decodeClassOfMessage(byte classOfMessage) {
76 return RmcpClassOfMessage.parseInt(TypeConverter.byteToInt(classOfMessage) & 0x9f);
77 // bits 5 and 6 are reserved so we need to get rid of them
78 }
79
80 private static byte[] decodeData(byte[] rawMessage) {
81 byte[] data = new byte[rawMessage.length - 4];
82 System.arraycopy(rawMessage, 4, data, 0, data.length);
83 return data;
84 }
85
86 }