Class ClientHello

java.lang.Object

tech.kwik.agent15.handshake.HandshakeMessage

tech.kwik.agent15.handshake.ClientHello

public class ClientHello
extends HandshakeMessage

https://datatracker.ietf.org/doc/html/rfc8446#section-4.1.2

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	ClientHello.PskKeyEstablishmentMode

Field Summary

Fields

Modifier and Type	Field	Description
static final List<TlsConstants.CipherSuite>	SUPPORTED_CIPHERS

Constructor Summary

Constructors

Constructor	Description
ClientHello(byte[] clientRandom, byte[] sessionId, List<TlsConstants.CipherSuite> cipherSuites, List<Extension> extensions, byte[] transcriptPrefix, BinderCalculator binderCalculator)	Creates a ClientHello message from its constituent parts, with a transcript prefix for computing the binder of a pre-shared key extension.
ClientHello(byte[] clientRandom, byte[] sessionId, List<TlsConstants.CipherSuite> cipherSuites, List<Extension> extensions, BinderCalculator binderCalculator)	Creates a ClientHello message from its constituent parts.
ClientHello(String serverName, List<KeyShareExtension.KeyShareEntry> keyShares, boolean compatibilityMode, List<TlsConstants.CipherSuite> supportedCiphers, List<TlsConstants.SignatureScheme> supportedSignatures, List<TlsConstants.NamedGroup> supportedGroups, List<Extension> extraExtensions, BinderCalculator binderCalculator, ClientHello.PskKeyEstablishmentMode pskKeyEstablishmentMode)	Creates a (first) ClientHello that offers a key share for each of the given groups.

Method Summary

Modifier and Type	Method	Description
byte[]	getBytes()
List<TlsConstants.CipherSuite>	getCipherSuites()
byte[]	getClientRandom()
List<Extension>	getExtensions()
int	getPskExtensionStartPosition()	Returns the start position of the PreSharedKeyExtension in the serialized ClientHello.
byte[]	getSessionId()
TlsConstants.HandshakeType	getType()
static ClientHello	parse(ByteBuffer buffer, ExtensionParser customExtensionParser)	Parses a ClientHello message from a byte stream.
String	toString()

Methods inherited from class HandshakeMessage

parseHandshakeHeader

Methods inherited from class Object

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

Field Details

SUPPORTED_CIPHERS

public static final List<TlsConstants.CipherSuite> SUPPORTED_CIPHERS

Constructor Details

ClientHello

public ClientHello(String serverName,
 List<KeyShareExtension.KeyShareEntry> keyShares,
 boolean compatibilityMode,
 List<TlsConstants.CipherSuite> supportedCiphers,
 List<TlsConstants.SignatureScheme> supportedSignatures,
 List<TlsConstants.NamedGroup> supportedGroups,
 List<Extension> extraExtensions,
 BinderCalculator binderCalculator,
 ClientHello.PskKeyEstablishmentMode pskKeyEstablishmentMode)

Creates a (first) ClientHello that offers a key share for each of the given groups. https://datatracker.ietf.org/doc/html/rfc8446#section-4.2.8 "Clients MAY send an empty client_shares vector in order to request group selection from the server, at the cost of an additional round trip"; this implementation always sends at least one key share.

Parameters:

serverName -

keyShares - the key shares to offer, in descending order of preference; must not be empty and each of its groups must occur in supportedGroups, in the same order.

compatibilityMode -

supportedCiphers -

supportedSignatures -

supportedGroups -

extraExtensions -

binderCalculator - can be null when no ClientHelloPreSharedKeyExtension is present, must be non-null when ClientHelloPreSharedKeyExtension is present.

pskKeyEstablishmentMode -

ClientHello

public ClientHello(byte[] clientRandom,
 byte[] sessionId,
 List<TlsConstants.CipherSuite> cipherSuites,
 List<Extension> extensions,
 BinderCalculator binderCalculator)

Creates a ClientHello message from its constituent parts. In contrast to the other constructors, this one does not add any extension by itself: the given extensions are serialized as they are, in the order given. This is what makes it possible to create the second ClientHello that must be sent in response to a HelloRetryRequest, which must be identical to the first one except for a limited set of changes, see https://datatracker.ietf.org/doc/html/rfc8446#section-4.1.2.

Parameters:

clientRandom - the client random; 32 bytes

sessionId - the legacy session id; empty when not using compatibility mode

cipherSuites - the symmetric cipher options supported, in descending order of preference

extensions - the extensions, in the order in which they must be serialized

binderCalculator - can be null when no ClientHelloPreSharedKeyExtension is present, must be non-null when ClientHelloPreSharedKeyExtension is present.

ClientHello

public ClientHello(byte[] clientRandom,
 byte[] sessionId,
 List<TlsConstants.CipherSuite> cipherSuites,
 List<Extension> extensions,
 byte[] transcriptPrefix,
 BinderCalculator binderCalculator)

Creates a ClientHello message from its constituent parts, with a transcript prefix for computing the binder of a pre-shared key extension. This is what the second ClientHello (the one sent in response to a HelloRetryRequest) needs, see https://datatracker.ietf.org/doc/html/rfc8446#section-4.2.11.2.

Parameters:

clientRandom - the client random; 32 bytes

sessionId - the legacy session id; empty when not using compatibility mode

cipherSuites - the symmetric cipher options supported, in descending order of preference

extensions - the extensions, in the order in which they must be serialized

transcriptPrefix - the transcript that precedes this client hello; empty for a first client hello

binderCalculator - can be null when no ClientHelloPreSharedKeyExtension is present, must be non-null when ClientHelloPreSharedKeyExtension is present.

Method Details

parse

public static ClientHello parse(ByteBuffer buffer,
 ExtensionParser customExtensionParser)
                         throws TlsProtocolException,
IllegalParameterAlert

Parses a ClientHello message from a byte stream.

Parameters:

buffer - the buffer to read the message from

customExtensionParser - parser for extensions not known to this implementation; may be null

Throws:

TlsProtocolException

IllegalParameterAlert

getType

public TlsConstants.HandshakeType getType()

Specified by:

getType in class HandshakeMessage

getBytes

public byte[] getBytes()

Specified by:

getBytes in class HandshakeMessage

getClientRandom

public byte[] getClientRandom()

getSessionId

public byte[] getSessionId()

getCipherSuites

public List<TlsConstants.CipherSuite> getCipherSuites()

getExtensions

public List<Extension> getExtensions()

getPskExtensionStartPosition

public int getPskExtensionStartPosition()

Returns the start position of the PreSharedKeyExtension in the serialized ClientHello. This is needed for computing binders.

Returns:

the start position or -1 if not present.

toString

public String toString()

Overrides:

toString in class Object