noise_frame_helper.hpp

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#pragma once
 
 
#include <esphome/api/bytes.hpp>
#include <esphome/api/crypto/cipher_state.hpp>
#include <esphome/api/crypto/noise_handshake.hpp>
#include <esphome/api/crypto/primitives.hpp>
#include <esphome/api/frame/frame_helper.hpp>
 
#include <cstddef>
#include <cstdint>
#include <string>
 
namespace esphome::api {
 
struct NoiseConfig {
    std::string psk_base64;
    std::string expected_name;
};
 
class NoiseFrameHelper final : public FrameHelper {
public:
    static constexpr std::uint8_t indicator = 0x01;
 
    explicit NoiseFrameHelper(const NoiseConfig& config);
 
    void encode(std::uint32_t msg_type, ByteView payload, ByteBuffer& out) override;
    void feed(ByteView data) override;
    FrameStatus next(std::uint32_t& out_type, ByteView& out_payload) override;
 
    [[nodiscard]] bool needs_handshake() const override {
        return true;
    }
    ByteBuffer connect_bytes() override;
    void set_handshake_handlers(HandshakeReady on_ready, HandshakeError on_error) override;
 
    [[nodiscard]] const std::string& server_name() const noexcept {
        return server_name_;
    }
 
private:
    enum class State { ExpectServerHello, ExpectHandshake, Ready, Failed };
 
    FrameStatus next_raw(ByteView& out_payload);
    void compact();
    void handle_server_hello(ByteView payload);
    void handle_server_handshake(ByteView payload);
    void report_error(const std::string& what);
 
    noise::SymmetricKey psk_{};
    std::string expected_name_;
    std::string server_name_;
 
    noise::NoiseHandshake handshake_;
    noise::CipherState encrypt_;
    noise::CipherState decrypt_;
    State state_ = State::ExpectServerHello;
 
    HandshakeReady on_ready_;
    HandshakeError on_error_;
 
    ByteBuffer buffer_;
    std::size_t consumed_ = 0;
    ByteBuffer plaintext_;
};
 
}  // namespace esphome::api