Class Decoder

java.lang.Object

net.schmizz.sshj.transport.Converter

net.schmizz.sshj.transport.Decoder

final class Decoder
extends Converter

Decodes packets from the SSH binary protocol per the current algorithms.

Field Summary

Fields

Modifier and Type	Field	Description
private final SSHPacket	inputBuffer	Buffer where as-yet undecoded data lives
private final org.slf4j.Logger	log
private byte[]	macResult	MAC result is stored here
private static final int	MAX_PACKET_LEN
private int	needed	How many bytes do we need, before a call to decode() can succeed at decoding at least packet length, OR the whole packet?
private final SSHPacketHandler	packetHandler	What we pass decoded packets to
private int	packetLength	-1 if packet length not yet been decoded, else the packet length
private final SSHPacket	uncompressBuffer	Used in case compression is active to store the uncompressed data

Fields inherited from class Converter

authed, authMode, cipher, cipherSize, compression, etm, mac, seq

Constructor Summary

Constructors

Constructor	Description
Decoder(Transport packetHandler)

Method Summary

Modifier and Type	Method	Description
private void	checkMAC(byte[] data)
private void	checkPacketLength(int len)
private int	decode()	Returns advised number of bytes that should be made available in decoderBuffer before the method should be called again.
private SSHPacket	decompressed()
private void	decryptBuffer(int offset, int length)
private int	decryptLength()
private int	decryptLengthAAD()
(package private) Compression.Mode	getCompressionType()
(package private) int	getMaxPacketLength()
(package private) int	received(byte[] b, int len)	Adds len bytes from b to the decoder buffer.
(package private) void	setAlgorithms(Cipher cipher, MAC mac, Compression compression)

Methods inherited from class Converter

getSequenceNumber, isSequenceNumberAtMax, resetSequenceNumber, setAuthenticated, usingCompression

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

MAX_PACKET_LEN

private static final int MAX_PACKET_LEN

See Also:

• Constant Field Values

log

private final org.slf4j.Logger log

packetHandler

private final SSHPacketHandler packetHandler

What we pass decoded packets to

inputBuffer

private final SSHPacket inputBuffer

Buffer where as-yet undecoded data lives

uncompressBuffer

private final SSHPacket uncompressBuffer

Used in case compression is active to store the uncompressed data

macResult

private byte[] macResult

MAC result is stored here

packetLength

private int packetLength

-1 if packet length not yet been decoded, else the packet length

needed

private int needed

How many bytes do we need, before a call to decode() can succeed at decoding at least packet length, OR the whole packet?

Constructor Details

Decoder

Decoder(Transport packetHandler)

Method Details

decode

private int decode()
            throws SSHException

Returns advised number of bytes that should be made available in decoderBuffer before the method should be called again.

Returns:

number of bytes needed before further decoding possible

Throws:

SSHException

checkMAC

private void checkMAC(byte[] data)
               throws TransportException

Throws:

TransportException

decompressed

private SSHPacket decompressed()
                        throws TransportException

Throws:

TransportException

decryptLengthAAD

private int decryptLengthAAD()
                      throws TransportException

Throws:

TransportException

decryptLength

private int decryptLength()
                   throws TransportException

Throws:

TransportException

decryptBuffer

private void decryptBuffer(int offset,
 int length)

checkPacketLength

private void checkPacketLength(int len)
                        throws TransportException

Throws:

TransportException

received

int received(byte[] b,
 int len)
      throws SSHException

Adds len bytes from b to the decoder buffer. When a packet has been successfully decoded, hooks in to SSHPacketHandler.handle(Message, SSHPacket) of the SSHPacketHandler this decoder was initialized with.

Returns the number of bytes expected in the next call in order to decode the packet length, and if the packet length has already been decoded; to decode the payload. This number is accurate and should be taken to heart.

Throws:

SSHException

setAlgorithms

void setAlgorithms(Cipher cipher,
 MAC mac,
 Compression compression)

Overrides:

setAlgorithms in class Converter

getCompressionType

Compression.Mode getCompressionType()

Specified by:

getCompressionType in class Converter

getMaxPacketLength

int getMaxPacketLength()