/*
* Copyright (C)2009 - SSHJ Contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.schmizz.sshj.transport;
import net.schmizz.sshj.transport.cipher.Cipher;
import net.schmizz.sshj.transport.cipher.NoneCipher;
import net.schmizz.sshj.transport.compression.Compression;
import net.schmizz.sshj.transport.mac.MAC;
/**
* Base class for {@link Encoder} and {@link Decoder}.
* <p/>
* From RFC 4253, p. 6
* <p/>
* <pre>
* Each packet is in the following format:
*
* uint32 packet_length
* byte padding_length
* byte[n1] payload; n1 = packet_length - padding_length - 1
* byte[n2] random padding; n2 = padding_length
* byte[m] mac (Message Authentication Code - MAC); m = mac_length
* </pre>
*/
abstract class Converter {
protected Cipher cipher = new NoneCipher();
protected MAC mac = null;
protected Compression compression = null;
protected int cipherSize = 8;
protected long seq = -1;
protected boolean authed;
long getSequenceNumber() {
return seq;
}
void setAlgorithms(Cipher cipher, MAC mac, Compression compression) {
this.cipher = cipher;
this.mac = mac;
this.compression = compression;
if (compression != null)
compression.init(getCompressionType());
this.cipherSize = cipher.getIVSize();
}
void setAuthenticated() {
this.authed = true;
}
boolean usingCompression() {
return compression != null && (authed || !compression.isDelayed());
}
abstract Compression.Mode getCompressionType();
}