Method handshake

gmtls/gm_handshake_client_double.go:67–158

Does the handshake, either a full one or resumes old session. Requires hs.c, hs.hello, and, optionally, hs.session to be set.

()

// Does the handshake, either a full one or resumes old session.
// Requires hs.c, hs.hello, and, optionally, hs.session to be set.
func (hs *clientHandshakeStateGM) handshake() error {
	c := hs.c

	// send ClientHello
	if _, err := c.writeRecord(recordTypeHandshake, hs.hello.marshal()); err != nil {
		return err
	}

	msg, err := c.readHandshake()
	if err != nil {
		return err
	}

	var ok bool
	if hs.serverHello, ok = msg.(*serverHelloMsg); !ok {
		c.sendAlert(alertUnexpectedMessage)
		return unexpectedMessageError(hs.serverHello, msg)
	}

	if hs.serverHello.vers != VersionGMSSL {
		hs.c.sendAlert(alertProtocolVersion)
		return fmt.Errorf("tls: server selected unsupported protocol version %x, while expecting %x", hs.serverHello.vers, VersionGMSSL)
	}

	if err = hs.pickCipherSuite(); err != nil {
		return err
	}

	isResume, err := hs.processServerHello()
	if err != nil {
		return err
	}

	hs.finishedHash = newFinishedHashGM(hs.suite)

	// No signatures of the handshake are needed in a resumption.
	// Otherwise, in a full handshake, if we don't have any certificates
	// configured then we will never send a CertificateVerify message and
	// thus no signatures are needed in that case either.
	if isResume || (len(c.config.Certificates) == 0 && c.config.GetClientCertificate == nil) {
		hs.finishedHash.discardHandshakeBuffer()
	}

	hs.finishedHash.Write(hs.hello.marshal())
	hs.finishedHash.Write(hs.serverHello.marshal())

	c.buffering = true
	if isResume {
		if err := hs.establishKeys(); err != nil {
			return err
		}
		if err := hs.readSessionTicket(); err != nil {
			return err
		}
		if err := hs.readFinished(c.serverFinished[:]); err != nil {
			return err
		}
		c.clientFinishedIsFirst = false