com.veraxsystems.vxipmi.coding.protocol.encoder.Protocolv15Encoder Maven / Gradle / Ivy

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/*
 * Protocolv15Encoder.java 
 * Created on 2011-07-21
 *
 * Copyright (c) Verax Systems 2011.
 * All rights reserved.
 *
 * This software is furnished under a license. Use, duplication,
 * disclosure and all other uses are restricted to the rights
 * specified in the written license agreement.
 */
package com.veraxsystems.vxipmi.coding.protocol.encoder;

import com.veraxsystems.vxipmi.coding.protocol.AuthenticationType;
import com.veraxsystems.vxipmi.coding.protocol.IpmiMessage;
import com.veraxsystems.vxipmi.coding.protocol.Ipmiv15Message;
import com.veraxsystems.vxipmi.common.TypeConverter;

import java.security.InvalidKeyException;

/**
 * Encodes IPMI v1.5 message
 */
public class Protocolv15Encoder extends ProtocolEncoder {

    /**
     * @param ipmiMessage
     *            - IPMI message to be encoded. Must be {@link Ipmiv15Message}.
     * @throws InvalidKeyException
     *             - when initiation of the confidentiality algorithm fails
     * @throws IllegalArgumentException
     *             when IPMI protocol version is incorrect.
     * @see Ipmiv15Message
     */
    @Override
    public byte[] encode(IpmiMessage ipmiMessage) throws InvalidKeyException {
        if (!(ipmiMessage instanceof Ipmiv15Message)) {
            throw new IllegalArgumentException(
                    "IPMIMessage must be in 1.5 version.");
        }
        Ipmiv15Message message = (Ipmiv15Message) ipmiMessage;

        byte[] raw = new byte[getMessageLength(message)];

        raw[0] = encodeAuthenticationType(message.getAuthenticationType());

        int offset = 1;

        encodeSessionSequenceNumber(message.getSessionSequenceNumber(), raw,
                offset);
        offset += 4;

        encodeSessionId(message.getSessionID(), raw, offset);
        offset += 4;

        if (message.getAuthenticationType() != AuthenticationType.None) {
            encodeAuthenticationCode(message.getAuthCode(), raw, offset);
            offset += message.getAuthCode().length;
        }

        byte[] payload = message.getPayload().getEncryptedPayload();

        if (payload == null) {
            message.getPayload().encryptPayload(
                    message.getConfidentialityAlgorithm());
            payload = message.getPayload().getEncryptedPayload();
        }

        encodePayloadLength(payload.length, raw, offset);
        ++offset;

        offset = encodePayload(payload, raw, offset);

        encodeSessionTrailer(raw, offset);

        return raw;
    }

    private int getMessageLength(IpmiMessage ipmiMessage) {
        int length = 11
                + ipmiMessage.getConfidentialityAlgorithm()
                        .getConfidentialityOverheadSize(
                                ipmiMessage.getPayloadLength())
                + ipmiMessage.getPayloadLength();

        if (ipmiMessage.getAuthenticationType() != AuthenticationType.None) {
            length += 16;
        }

        return length;
    }

    /**
     * Inserts authentication code into message at given offset.
     *
     * @param authCode
     * @param message
     *            - message being encoded
     * @param offset
     * @throws IndexOutOfBoundsException
     *             when message is too short to hold value at given offset
     */
    private void encodeAuthenticationCode(byte[] authCode, byte[] message, int offset) {
        if (authCode.length + offset > message.length) {
            throw new IndexOutOfBoundsException("Message is too short");
        }
        System.arraycopy(authCode, 0, message, offset, authCode.length);
    }

    @Override
    protected void encodePayloadLength(int value, byte[] message, int offset) {
        message[offset] = TypeConverter.intToByte(value);
    }

    /**
     * Creates session trailer. 

     * Creates an inserts Legacy PAD.
     *
     * @param message
     *            - IPMI message being created
     * @param offset
     *            - Should point at the beginning of the session trailer.
     * @throws IndexOutOfBoundsException
     *             when message is too short to hold value at given offset
     * @return Offset pointing after Authorization Code
     */
    private int encodeSessionTrailer(byte[] message, int offset) {
        if (1 + offset > message.length) {
            throw new IndexOutOfBoundsException("Message is too short");
        }

        message[offset] = 0;

        return offset + 1;
    }
}