Golang MessageStream.WriteMessage方法代码示例

func sendError(err error, ms *util.MessageStream) {
	var errStr = ""
	if err != nil {
		errStr = err.Error()
	}
	resp := &domain_service.DomainServiceResponse{ErrorMessage: &errStr}
	if _, err := ms.WriteMessage(resp); err != nil {
		log.Printf("domain_server: Error sending resp on the channel: %s\n ", err)
	}
}

func (conn *Conn) sendCredentials(ms util.MessageStream) {
	if conn.Authenticate && conn.delegation != nil {
		ms.WriteString("delegation")
		ms.WriteMessage(conn.delegation)
	} else if conn.Authenticate {
		ms.WriteString("key")
	} else {
		ms.WriteString("anonymous")
	}
}

// SetCounter sets the remote counter for this program.
func SetCounter(ms *util.MessageStream, counter uint64) error {
	rm := &RollbackMessage{
		Type: RollbackMessageType_SET_COUNTER.Enum(),
		Data: EncodeCounter(counter),
	}
	if _, err := ms.WriteMessage(rm); err != nil {
		return err
	}

	// TODO(tmroeder): we currently ignore the value of the counter returned
	// by the server.
	return checkResponse(ms)
}

// sendResult sends an OperationResult with the given value on the given stream.
func sendResult(ms util.MessageStream, result bool) error {
	res := &OperationResult{Result: proto.Bool(result)}
	ar := &Message{
		Type: MessageType_OP_RES.Enum(),
	}
	var err error
	if ar.Data, err = proto.Marshal(res); err != nil {
		return err
	}

	if _, err := ms.WriteMessage(ar); err != nil {
		return err
	}

	return nil
}

// SetHash sets the value of a hash for a given item for this program.
func SetHash(ms *util.MessageStream, item string, hash []byte) error {
	rh := &RollbackHash{
		Item: proto.String(item),
		Hash: hash,
	}
	rhb, err := proto.Marshal(rh)
	if err != nil {
		return err
	}
	rm := &RollbackMessage{
		Type: RollbackMessageType_SET_HASH.Enum(),
		Data: rhb,
	}
	if _, err := ms.WriteMessage(rm); err != nil {
		return err
	}

	return checkResponse(ms)
}

// AuthenticatePrincipal is a client method used to send a request to a
// ResourceMaster to authenticate a principal with a given certificate and a
// given set of keys.
func AuthenticatePrincipal(ms util.MessageStream, key *tao.Keys, derCert []byte) error {
	// Send the authentication request, which supposes that a server is
	// waiting to receive this request.
	c := &Message{
		Type: MessageType_AUTH_CERT.Enum(),
		Data: derCert,
	}
	if _, err := ms.WriteMessage(c); err != nil {
		return err
	}

	// Receive a challenge nonce from the server.
	var nc Message
	if err := ms.ReadMessage(&nc); err != nil {
		return err
	}
	if *nc.Type != MessageType_NONCE_CHALL {
		return fmt.Errorf("didn't receive NONCE_CHALL from the server")
	}

	// Sign the nonce.
	sn := &Message{
		Type: MessageType_SIGNED_NONCE.Enum(),
	}
	var err error
	if sn.Data, err = key.SigningKey.Sign(nc.Data, ChallengeContext); err != nil {
		return err
	}
	if _, err := ms.WriteMessage(sn); err != nil {
		return err
	}

	// Get the result from the server after verificaton.
	res, err := readResult(ms)
	if err != nil {
		return err
	}

	if !res {
		return fmt.Errorf("the signed nonce failed verification")
	}
	return nil
}

// GetCounter implements RollbackMessageType_GET_COUNTER and returns the current
// value of a counter to the requestor.
func (r *RollbackMaster) GetCounter(ms *util.MessageStream, name string) error {
	var emptyData []byte
	rr := &RollbackResponse{
		Type: RollbackMessageType_ERROR.Enum(),
		Data: emptyData,
	}

	p := r.FindRollbackProgram(name)
	if p == nil {
		if _, err := ms.WriteMessage(rr); err != nil {
			return err
		}
		return fmt.Errorf("couldn't find a rollback program with name %s", name)
	}

	rr.Type = RollbackMessageType_GET_COUNTER.Enum()
	rr.Data = EncodeCounter(p.MonotonicCounter)
	_, err := ms.WriteMessage(rr)
	return err
}

// GetHashedVerifier gets the hash of the counter and the item hash for a given
// item.
func GetHashedVerifier(ms *util.MessageStream, item string) ([]byte, error) {
	rm := &RollbackMessage{
		Type: RollbackMessageType_GET_HASHED_VERIFIER.Enum(),
		Data: []byte(item),
	}
	if _, err := ms.WriteMessage(rm); err != nil {
		return nil, err
	}

	// We can't use checkResponse here since we need to get the value out of
	// the response to read the hash.
	var rr RollbackResponse
	if err := ms.ReadMessage(&rr); err != nil {
		return nil, err
	}
	if *rr.Type == RollbackMessageType_ERROR {
		return nil, fmt.Errorf("couldn't set the counter on the remote server")
	}

	return rr.Data, nil
}

// sendOperation is a helper method that sets up the data structures needed for
// a FileOperation message like CREATE, WRITE, or READ, and sends this message
// on the MessageStream.
func sendOperation(ms util.MessageStream, mt MessageType, cert []byte, name string) error {
	fop := &FileOperation{
		Subject: cert,
		Name:    proto.String(name),
	}

	fopb, err := proto.Marshal(fop)
	if err != nil {
		return err
	}
	m := &Message{
		Type: mt.Enum(),
		Data: fopb,
	}

	if _, err := ms.WriteMessage(m); err != nil {
		return err
	}

	return nil
}

func sendResponse(ms util.MessageStream, resp *taoca.Response) {
	_, err := ms.WriteMessage(resp)
	if err != nil {
		fmt.Printf("error writing response: %s\n", err)
	}
}

//.........这里部分代码省略.........
		ctr = cipher.NewCTR(dec, iv)
		if ctr == nil {
			return fmt.Errorf("can't create AES-CTR encryption")
		}

		// Remove the HMAC-SHA256 output from the bytes to check.
		left = left - int64(hmacSize)

		// Secure decryption in this case requires reading the file
		// twice: once to check the MAC, and once to decrypt the bytes.
		// The MAC must be checked before *any* decryption occurs and
		// before *any* decrypted bytes are sent to the receiver.
		for {
			// Figure out how many bytes to read on this iteration.
			readSize := int64(bufferSize)
			final := false
			if left <= bufferSize {
				readSize = left
				final = true
			}

			// Read the (maybe encrypted) bytes from the file.
			n, err := file.Read(buf[:readSize])
			if err != nil {
				return err
			}
			left = left - int64(n)
			hm.Write(buf[:n])
			if final {
				break
			}
		}
		computed := hm.Sum(nil)
		original := buf[:hmacSize]

		// Read the file's version of the HMAC and check it securely
		// against the computed version.
		if _, err := file.Read(original); err != nil {
			return err
		}
		if !hmac.Equal(computed, original) {
			return fmt.Errorf("invalid file HMAC on decryption for file '%s'", fullpath)
		}

		// Go back to the beginning of the file (minus the IV) for
		// decryption.
		if _, err := file.Seek(ivSize, 0); err != nil {
			return fmt.Errorf("couldn't seek back to the beginning of file '%s': %s", fullpath, err)
		}

		// Reset the number of bytes so it only includes the encrypted
		// bytes.
		left = fileInfo.Size() - int64(ivSize+hmacSize)
	}

	// The input buffer, and a temporary buffer for holding decrypted
	// plaintext.
	temp := make([]byte, bufferSize)

	// Set up a framing message to use to send the data.
	m := &Message{
		Type: MessageType_FILE_NEXT.Enum(),
	}

	// Now that the integrity of the data has been verified, if needed, send
	// the data (after decryption, if necessary) to the receiver.
	for {
		// Figure out how many bytes to read on this iteration.
		readSize := int64(bufferSize)
		final := false
		if left <= bufferSize {
			readSize = left
			final = true
			m.Type = MessageType_FILE_LAST.Enum()
		}

		// Read the (maybe encrypted) bytes from the file.
		n, err := file.Read(buf[:readSize])
		if err != nil {
			return err
		}
		left = left - int64(n)

		if hasKeys {
			ctr.XORKeyStream(temp[:n], buf[:n])
			m.Data = temp[:n]
		} else {
			m.Data = buf[:n]
		}

		// Send the decrypted data to the receiver.
		if _, err := ms.WriteMessage(m); err != nil {
			return err
		}
		if final {
			break
		}
	}
	return nil
}