/*
* (C) 2021 Jack Lloyd
*     2021, 2022 René Meusel, Hannes Rantzsch - neXenio GmbH
*     2022       René Meusel - Rohde & Schwarz Cybersecurity GmbH
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include "tests.h"
#include <fstream>
#include <memory>
#include <utility>

// Since RFC 8448 uses a specific set of cipher suites we can only run this
// test if all of them are enabled.
#if defined(BOTAN_HAS_TLS_12) && defined(BOTAN_HAS_TLS_13) && defined(BOTAN_HAS_AEAD_CHACHA20_POLY1305) &&             \
   defined(BOTAN_HAS_AEAD_GCM) && defined(BOTAN_HAS_AES) && defined(BOTAN_HAS_X25519) && defined(BOTAN_HAS_SHA2_32) && \
   defined(BOTAN_HAS_SHA2_64) && defined(BOTAN_HAS_ECDSA) && defined(BOTAN_HAS_PSS)
   #define BOTAN_CAN_RUN_TEST_TLS_RFC8448
#endif

#if defined(BOTAN_CAN_RUN_TEST_TLS_RFC8448)
   #include "test_rng.h"

   #include <botan/assert.h>
   #include <botan/credentials_manager.h>
   #include <botan/data_src.h>
   #include <botan/dl_group.h>
   #include <botan/ec_group.h>
   #include <botan/hex.h>
   #include <botan/pk_algs.h>
   #include <botan/pkcs8.h>
   #include <botan/tls_callbacks.h>
   #include <botan/tls_client.h>
   #include <botan/tls_extensions_12.h>
   #include <botan/tls_extensions_13.h>
   #include <botan/tls_messages.h>
   #include <botan/tls_policy.h>
   #include <botan/tls_server.h>
   #include <botan/tls_session_manager.h>
   #include <botan/x509_key.h>
   #include <botan/x509cert.h>
   #include <botan/internal/concat_util.h>
   #include <botan/internal/fmt.h>
   #include <botan/internal/stl_util.h>
#endif

namespace Botan_Tests {

namespace {

#if defined(BOTAN_CAN_RUN_TEST_TLS_RFC8448)

void add_entropy(Fixed_Output_RNG& rng, const std::vector<uint8_t>& bin) {
   rng.add_entropy(bin.data(), bin.size());
}

Botan::X509_Certificate server_certificate() {
   // self-signed certificate with an RSA1024 public key valid until:
   //   Jul 30 01:23:59 2026 GMT
   Botan::DataSource_Memory in(Test::read_data_file("tls_13_rfc8448/server_certificate.pem"));
   return Botan::X509_Certificate(in);
}

Botan::X509_Certificate alternative_server_certificate() {
   // self-signed certificate with a P-256 public key valid until:
   //   Jul 30 01:24:00 2026 GMT
   //
   // This certificate is presented by the server in the "Client Authentication"
   // test case. Why the certificate differs in that case remains unclear.
   Botan::DataSource_Memory in(Test::read_data_file("tls_13_rfc8448/server_certificate_client_auth.pem"));
   return Botan::X509_Certificate(in);
}

Botan::X509_Certificate client_certificate() {
   // self-signed certificate with an RSA1024 public key valid until:
   //   Jul 30 01:23:59 2026 GMT
   Botan::DataSource_Memory in(Test::read_data_file("tls_13_rfc8448/client_certificate.pem"));
   return Botan::X509_Certificate(in);
}

std::unique_ptr<Botan::Private_Key> client_raw_public_key_pair() {
   // P-256 private key (independently generated)
   Botan::DataSource_Memory in(Test::read_data_file("tls_13_rfc8448/client_raw_public_keypair.pem"));
   return Botan::PKCS8::load_key(in);
}

std::unique_ptr<Botan::Private_Key> server_raw_public_key_pair() {
   // P-256 private key (independently generated)
   Botan::DataSource_Memory in(Test::read_data_file("tls_13_rfc8448/server_raw_public_keypair.pem"));
   return Botan::PKCS8::load_key(in);
}

/**
* Simple version of the Padding extension (RFC 7685) to reproduce the
* 2nd Client_Hello in RFC8448 Section 5 (HelloRetryRequest)
*/
class Padding final : public Botan::TLS::Extension {
   public:
      static Botan::TLS::Extension_Code static_type() {
         // NOLINTNEXTLINE(clang-analyzer-optin.core.EnumCastOutOfRange)
         return Botan::TLS::Extension_Code(21);
      }

      Botan::TLS::Extension_Code type() const override { return static_type(); }

      explicit Padding(const size_t padding_bytes) : m_padding_bytes(padding_bytes) {}

      std::vector<uint8_t> serialize(Botan::TLS::Connection_Side /*whoami*/) const override {
         return std::vector<uint8_t>(m_padding_bytes, 0x00);
      }

      bool empty() const override { return m_padding_bytes == 0; }

   private:
      size_t m_padding_bytes;
};

using namespace Botan;
using namespace Botan::TLS;

std::chrono::system_clock::time_point from_milliseconds_since_epoch(uint64_t msecs) {
   const int64_t secs_since_epoch = msecs / 1000;
   const uint32_t additional_millis = msecs % 1000;

   BOTAN_ASSERT_NOMSG(secs_since_epoch <= std::numeric_limits<time_t>::max());
   return std::chrono::system_clock::from_time_t(static_cast<time_t>(secs_since_epoch)) +
          std::chrono::milliseconds(additional_millis);
}

using Modify_Exts_Fn =
   std::function<void(Botan::TLS::Extensions&, Botan::TLS::Connection_Side, Botan::TLS::Handshake_Type)>;

/**
 * We cannot actually reproduce the signatures stated in RFC 8448 as their
 * signature scheme is probabilistic and we're lacking the correct RNG
 * input. Hence, signatures are know beforehand and just reproduced by the
 * TLS callback when requested.
 */
struct MockSignature {
      std::vector<uint8_t> message_to_sign;
      std::vector<uint8_t> signature_to_produce;
};

/**
 * Subclass of the Botan::TLS::Callbacks instrumenting all available callbacks.
 * The invocation counts can be checked in the integration tests to make sure
 * all expected callbacks are hit. Furthermore collects the received application
 * data and sent record bytes for further inspection by the test cases.
 */
class Test_TLS_13_Callbacks : public Botan::TLS::Callbacks {
   public:
      Test_TLS_13_Callbacks(Modify_Exts_Fn modify_exts_cb,
                            std::vector<MockSignature> mock_signatures,
                            uint64_t timestamp) :
            session_activated_called(false),
            m_modify_exts(std::move(modify_exts_cb)),
            m_mock_signatures(std::move(mock_signatures)),
            m_timestamp(from_milliseconds_since_epoch(timestamp)) {}

      void tls_emit_data(std::span<const uint8_t> data) override {
         count_callback_invocation("tls_emit_data");
         send_buffer.insert(send_buffer.end(), data.begin(), data.end());
      }

      void tls_record_received(uint64_t seq_no, std::span<const uint8_t> data) override {
         count_callback_invocation("tls_record_received");
         received_seq_no = seq_no;
         receive_buffer.insert(receive_buffer.end(), data.begin(), data.end());
      }

      void tls_alert(Botan::TLS::Alert alert) override {
         count_callback_invocation("tls_alert");
         BOTAN_UNUSED(alert);
         // handle a tls alert received from the tls server
      }

      bool tls_peer_closed_connection() override {
         count_callback_invocation("tls_peer_closed_connection");
         // we want to handle the closure ourselves
         return false;
      }

      void tls_session_established(const Botan::TLS::Session_Summary& summary) override {
         if(const auto& psk_id = summary.external_psk_identity()) {
            negotiated_psk_identity = *psk_id;
         }
         count_callback_invocation("tls_session_established");
      }

      void tls_session_activated() override {
         count_callback_invocation("tls_session_activated");
         session_activated_called = true;
      }

      bool tls_should_persist_resumption_information(const Session& /*session*/) override {
         count_callback_invocation("tls_should_persist_resumption_information");
         return true;  // should always store the session
      }

      void tls_verify_cert_chain(const std::vector<Botan::X509_Certificate>& cert_chain,
                                 const std::vector<std::optional<Botan::OCSP::Response>>& /*ocsp*/,
                                 const std::vector<Botan::Certificate_Store*>& /*trusted*/,
                                 Botan::Usage_Type /*usage*/,
                                 std::string_view /*hostname*/,
                                 const Botan::TLS::Policy& /*policy*/) override {
         count_callback_invocation("tls_verify_cert_chain");
         certificate_chain = cert_chain;
      }

      void tls_verify_raw_public_key(const Public_Key& raw_pk,
                                     Usage_Type /*usage*/,
                                     std::string_view /*hostname*/,
                                     const TLS::Policy& /*policy*/) override {
         count_callback_invocation("tls_verify_raw_public_key");
         // TODO: is there a better way to copy a generic public key?
         raw_public_key = Botan::X509::load_key(raw_pk.subject_public_key());
      }

      std::chrono::milliseconds tls_verify_cert_chain_ocsp_timeout() const override {
         count_callback_invocation("tls_verify_cert_chain");
         return std::chrono::milliseconds(0);
      }

      std::vector<uint8_t> tls_provide_cert_status(const std::vector<X509_Certificate>& chain,
                                                   const Certificate_Status_Request& csr) override {
         count_callback_invocation("tls_provide_cert_status");
         return Callbacks::tls_provide_cert_status(chain, csr);
      }

      std::vector<uint8_t> tls_sign_message(const Private_Key& key,
                                            RandomNumberGenerator& rng,
                                            std::string_view padding,
                                            Signature_Format format,
                                            const std::vector<uint8_t>& msg) override {
         BOTAN_UNUSED(key, rng);
         count_callback_invocation("tls_sign_message");

         if(key.algo_name() == "RSA") {
            if(format != Signature_Format::Standard) {
               throw Test_Error("TLS implementation selected unexpected signature format for RSA");
            }

            if(padding != "PSS(SHA-256,MGF1,32)") {
               throw Test_Error("TLS implementation selected unexpected padding for RSA: " + std::string(padding));
            }
         } else if(key.algo_name() == "ECDSA") {
            if(format != Signature_Format::DerSequence) {
               throw Test_Error("TLS implementation selected unexpected signature format for ECDSA");
            }

            if(padding != "SHA-256") {
               throw Test_Error("TLS implementation selected unexpected padding for ECDSA: " + std::string(padding));
            }
         } else {
            throw Test_Error("TLS implementation trying to sign with unexpected algorithm (" + key.algo_name() + ")");
         }

         for(const auto& mock : m_mock_signatures) {
            if(mock.message_to_sign == msg) {
               return mock.signature_to_produce;
            }
         }

         throw Test_Error("TLS implementation produced an unexpected message to be signed: " + Botan::hex_encode(msg));
      }

      bool tls_verify_message(const Public_Key& key,
                              std::string_view padding,
                              Signature_Format format,
                              const std::vector<uint8_t>& msg,
                              const std::vector<uint8_t>& sig) override {
         count_callback_invocation("tls_verify_message");
         return Callbacks::tls_verify_message(key, padding, format, msg, sig);
      }

      std::unique_ptr<PK_Key_Agreement_Key> tls_generate_ephemeral_key(
         const std::variant<TLS::Group_Params, DL_Group>& group, RandomNumberGenerator& rng) override {
         count_callback_invocation("tls_generate_ephemeral_key");
         return Callbacks::tls_generate_ephemeral_key(group, rng);
      }

      secure_vector<uint8_t> tls_ephemeral_key_agreement(const std::variant<TLS::Group_Params, DL_Group>& group,
                                                         const PK_Key_Agreement_Key& private_key,
                                                         const std::vector<uint8_t>& public_value,
                                                         RandomNumberGenerator& rng,
                                                         const Policy& policy) override {
         count_callback_invocation("tls_ephemeral_key_agreement");
         return Callbacks::tls_ephemeral_key_agreement(group, private_key, public_value, rng, policy);
      }

      void tls_inspect_handshake_msg(const Handshake_Message& message) override {
         count_callback_invocation("tls_inspect_handshake_msg_" + message.type_string());

         try {
            auto serialized_message = message.serialize();

            serialized_messages.try_emplace(message.type_string())
               .first->second.emplace_back(std::move(serialized_message));
         } catch(const Not_Implemented&) {
            // TODO: Once the server implementation is finished, this crutch
            //       can likely be removed, as all message types will have a
            //       serialization method with actual business logic. :o)
         }

         return Callbacks::tls_inspect_handshake_msg(message);
      }

      std::string tls_server_choose_app_protocol(const std::vector<std::string>& client_protos) override {
         count_callback_invocation("tls_server_choose_app_protocol");
         return Callbacks::tls_server_choose_app_protocol(client_protos);
      }

      void tls_modify_extensions(Botan::TLS::Extensions& exts,
                                 Botan::TLS::Connection_Side side,
                                 Botan::TLS::Handshake_Type which_message) override {
         count_callback_invocation(std::string("tls_modify_extensions_") + handshake_type_to_string(which_message));
         m_modify_exts(exts, side, which_message);
         Callbacks::tls_modify_extensions(exts, side, which_message);
      }

      void tls_examine_extensions(const Botan::TLS::Extensions& extn,
                                  Connection_Side which_side,
                                  Botan::TLS::Handshake_Type which_message) override {
         count_callback_invocation(std::string("tls_examine_extensions_") + handshake_type_to_string(which_message));
         return Callbacks::tls_examine_extensions(extn, which_side, which_message);
      }

      std::string tls_peer_network_identity() override {
         count_callback_invocation("tls_peer_network_identity");
         return Callbacks::tls_peer_network_identity();
      }

      std::chrono::system_clock::time_point tls_current_timestamp() override {
         count_callback_invocation("tls_current_timestamp");
         return m_timestamp;
      }

      std::vector<uint8_t> pull_send_buffer() { return std::exchange(send_buffer, std::vector<uint8_t>()); }

      std::vector<uint8_t> pull_receive_buffer() { return std::exchange(receive_buffer, std::vector<uint8_t>()); }

      uint64_t last_received_seq_no() const { return received_seq_no; }

      const std::map<std::string, unsigned int>& callback_invocations() const { return m_callback_invocations; }

      void reset_callback_invocation_counters() { m_callback_invocations.clear(); }

   private:
      void count_callback_invocation(const std::string& callback_name) const {
         if(!m_callback_invocations.contains(callback_name)) {
            m_callback_invocations[callback_name] = 0;
         }

         m_callback_invocations[callback_name]++;
      }

   public:
      bool session_activated_called;                           // NOLINT(*-non-private-member-variable*)
      std::vector<Botan::X509_Certificate> certificate_chain;  // NOLINT(*-non-private-member-variable*)
      std::unique_ptr<Botan::Public_Key> raw_public_key;       // NOLINT(*-non-private-member-variable*)
      std::string negotiated_psk_identity;                     // NOLINT(*-non-private-member-variable*)
      std::map<std::string, std::vector<std::vector<uint8_t>>>
         serialized_messages;  // NOLINT(*-non-private-member-variable*)

   private:
      std::vector<uint8_t> send_buffer;
      std::vector<uint8_t> receive_buffer;
      uint64_t received_seq_no = 0;
      Modify_Exts_Fn m_modify_exts;
      std::vector<MockSignature> m_mock_signatures;
      std::chrono::system_clock::time_point m_timestamp;

      mutable std::map<std::string, unsigned int> m_callback_invocations;
};

class Test_Credentials : public Botan::Credentials_Manager {
   public:
      explicit Test_Credentials(bool use_alternative_server_certificate, std::optional<ExternalPSK> external_psk) :
            m_alternative_server_certificate(use_alternative_server_certificate),
            m_external_psk(std::move(external_psk)) {
         Botan::DataSource_Memory in(Test::read_data_file("tls_13_rfc8448/server_key.pem"));
         m_server_private_key.reset(Botan::PKCS8::load_key(in).release());

         // RFC 8448 does not actually provide these keys. Hence we generate one on the
         // fly as a stand-in. Instead of actually using it, the signatures generated
         // by this private key must be hard-coded in `Callbacks::sign_message()`; see
         // `MockSignature_Fn` for more details.
         auto rng = Test::new_rng(__func__);
         m_bogus_alternative_server_private_key.reset(create_private_key("ECDSA", *rng, "secp256r1").release());

         m_client_private_key.reset(create_private_key("RSA", *rng, "1024").release());
      }

      std::vector<Botan::X509_Certificate> cert_chain(const std::vector<std::string>& cert_key_types,
                                                      const std::vector<AlgorithmIdentifier>& cert_signature_schemes,
                                                      const std::string& type,
                                                      const std::string& context) override {
         BOTAN_UNUSED(cert_key_types, cert_signature_schemes, context);
         if(type == "tls-client") {
            return {client_certificate()};
         } else if(m_alternative_server_certificate) {
            return {alternative_server_certificate()};
         } else {
            return {server_certificate()};
         }
      }

      std::shared_ptr<Public_Key> find_raw_public_key(const std::vector<std::string>& key_types,
                                                      const std::string& type,
                                                      const std::string& context) override {
         BOTAN_UNUSED(key_types, type, context);
         return (type == "tls-client") ? client_raw_public_key_pair()->public_key()
                                       : server_raw_public_key_pair()->public_key();
      }

      std::shared_ptr<Botan::Private_Key> private_key_for(const Botan::X509_Certificate& cert,
                                                          const std::string& type,
                                                          const std::string& context) override {
         BOTAN_UNUSED(cert, context);

         if(type == "tls-client") {
            return m_client_private_key;
         }

         if(m_alternative_server_certificate) {
            return m_bogus_alternative_server_private_key;
         }

         return m_server_private_key;
      }

      std::shared_ptr<Botan::Private_Key> private_key_for(const Public_Key& raw_public_key,
                                                          const std::string& type,
                                                          const std::string& context) override {
         BOTAN_UNUSED(type, context);
         std::vector<std::unique_ptr<Botan::Private_Key>> keys;
         keys.emplace_back(client_raw_public_key_pair());
         keys.emplace_back(server_raw_public_key_pair());
         for(auto& key : keys) {
            if(key->fingerprint_public() == raw_public_key.fingerprint_public()) {
               return std::move(key);
            }
         }
         return nullptr;
      }

      std::vector<TLS::ExternalPSK> find_preshared_keys(std::string_view /* host */,
                                                        TLS::Connection_Side /* whoami */,
                                                        const std::vector<std::string>& identities,
                                                        const std::optional<std::string>& prf) override {
         if(!m_external_psk.has_value()) {
            return {};
         }

         ExternalPSK& epsk = m_external_psk.value();
         const auto found = std::find(identities.begin(), identities.end(), epsk.identity());
         if(!identities.empty() && found == identities.end()) {
            return {};
         }

         if(prf && prf != epsk.prf_algo()) {
            return {};
         }

         // ExternalPSK has a deleted copy constructor. We need to do some gymnastics
         // to copy it and leave the data in m_external_psk intact
         const auto secret = epsk.extract_master_secret();
         m_external_psk = ExternalPSK(epsk.identity(), epsk.prf_algo(), secret);
         std::vector<ExternalPSK> psks;
         psks.emplace_back(epsk.identity(), epsk.prf_algo(), secret);
         return psks;
      }

   private:
      bool m_alternative_server_certificate;
      std::optional<ExternalPSK> m_external_psk;
      std::shared_ptr<Private_Key> m_client_private_key;
      std::shared_ptr<Private_Key> m_bogus_alternative_server_private_key;
      std::shared_ptr<Private_Key> m_server_private_key;
};

class RFC8448_Text_Policy : public Botan::TLS::Text_Policy {
   private:
      Botan::TLS::Text_Policy read_policy(const std::string& policy_file) {
         const std::string fspath = Test::data_file("tls-policy/" + policy_file + ".txt");

         std::ifstream is(fspath.c_str());
         if(!is.good()) {
            throw Test_Error("Missing policy file " + fspath);
         }

         return Botan::TLS::Text_Policy(is);
      }

   public:
      explicit RFC8448_Text_Policy(const std::string& policy_file, bool rfc8448 = true) :
            Botan::TLS::Text_Policy(read_policy(policy_file)), m_rfc8448(rfc8448) {}

      std::vector<Botan::TLS::Signature_Scheme> allowed_signature_schemes() const override {
         if(!m_rfc8448) {
            return Botan::TLS::Text_Policy::allowed_signature_schemes();
         }

         // We extend the allowed signature schemes with algorithms that we don't
         // actually support. The nature of the RFC 8448 test forces us to generate
         // bit-compatible TLS messages. Unfortunately, the test data offers all
         // those algorithms in its Client Hellos.
         return {
            Botan::TLS::Signature_Scheme::ECDSA_SHA256,
            Botan::TLS::Signature_Scheme::ECDSA_SHA384,
            Botan::TLS::Signature_Scheme::ECDSA_SHA512,
            Botan::TLS::Signature_Scheme::ECDSA_SHA1,  // not actually supported
            Botan::TLS::Signature_Scheme::RSA_PSS_SHA256,
            Botan::TLS::Signature_Scheme::RSA_PSS_SHA384,
            Botan::TLS::Signature_Scheme::RSA_PSS_SHA512,
            Botan::TLS::Signature_Scheme::RSA_PKCS1_SHA256,
            Botan::TLS::Signature_Scheme::RSA_PKCS1_SHA384,
            Botan::TLS::Signature_Scheme::RSA_PKCS1_SHA512,
            Botan::TLS::Signature_Scheme::RSA_PKCS1_SHA1,  // not actually supported
            Botan::TLS::Signature_Scheme(0x0402),          // DSA_SHA256, not actually supported
            Botan::TLS::Signature_Scheme(0x0502),          // DSA_SHA384, not actually supported
            Botan::TLS::Signature_Scheme(0x0602),          // DSA_SHA512, not actually supported
            Botan::TLS::Signature_Scheme(0x0202),          // DSA_SHA1, not actually supported
         };
      }

      // Overriding the key exchange group selection to favour the server's key
      // exchange group preference. This is required to enforce a Hello Retry Request
      // when testing RFC 8448 5. from the server side.
      Named_Group choose_key_exchange_group(const std::vector<Group_Params>& supported_by_peer,
                                            const std::vector<Group_Params>& offered_by_peer) const override {
         BOTAN_UNUSED(offered_by_peer);

         const auto supported_by_us = key_exchange_groups();
         const auto selected_group =
            std::find_if(supported_by_us.begin(), supported_by_us.end(), [&](const auto group) {
               return value_exists(supported_by_peer, group);
            });

         return selected_group != supported_by_us.end() ? *selected_group : Named_Group::NONE;
      }

   private:
      bool m_rfc8448;
};

/**
 * In-Memory Session Manager that stores sessions verbatim, without encryption.
 * Therefor it is not dependent on a random number generator and can easily be
 * instrumented for test inspection.
 */
class RFC8448_Session_Manager : public Botan::TLS::Session_Manager {
   private:
      decltype(auto) find_by_handle(const Session_Handle& handle) {
         return [=](const Session_with_Handle& session) {
            if(session.handle.id().has_value() && handle.id().has_value() &&
               session.handle.id().value() == handle.id().value()) {
               return true;
            }
            if(session.handle.ticket().has_value() && handle.ticket().has_value() &&
               session.handle.ticket().value() == handle.ticket().value()) {
               return true;
            }
            return false;
         };
      }

   public:
      RFC8448_Session_Manager() : Session_Manager(std::make_shared<Botan::Null_RNG>()) {}

      const std::vector<Session_with_Handle>& all_sessions() const { return m_sessions; }

      void store(const Session& session, const Session_Handle& handle) override {
         m_sessions.push_back({session, handle});
      }

      std::optional<Session_Handle> establish(const Session& session,
                                              const std::optional<Session_ID>& /*session*/,
                                              bool /*no_ticket*/) override {
         // we assume that the 'mocked' session is already stored in the manager,
         // verify that it is equivalent to the one created by the testee and
         // return the associated handle stored with it

         if(m_sessions.size() != 1) {
            throw Test_Error("No mocked session handle available; Test bug?");
         }

         const auto& [mocked_session, handle] = m_sessions.front();
         if(mocked_session.master_secret() != session.master_secret()) {
            throw Test_Error("Generated session object does not match the expected mock");
         }

         return handle;
      }

      std::optional<Session> retrieve_one(const Session_Handle& handle) override {
         auto itr = std::find_if(m_sessions.begin(), m_sessions.end(), find_by_handle(handle));
         if(itr == m_sessions.end()) {
            return std::nullopt;
         } else {
            return itr->session;
         }
      }

      std::vector<Session_with_Handle> find_some(const Server_Information& info,
                                                 const size_t /*max_sessions_hint*/) override {
         std::vector<Session_with_Handle> found_sessions;
         for(const auto& [session, handle] : m_sessions) {
            if(session.server_info() == info) {
               found_sessions.emplace_back(Session_with_Handle{session, handle});
            }
         }

         return found_sessions;
      }

      size_t remove(const Session_Handle& handle) override { return std::erase_if(m_sessions, find_by_handle(handle)); }

      size_t remove_all() override {
         const auto sessions = m_sessions.size();
         m_sessions.clear();
         return sessions;
      }

   private:
      std::vector<Session_with_Handle> m_sessions;
};

/**
 * This steers the TLS client handle and is the central entry point for the
 * test cases to interact with the TLS 1.3 implementation.
 *
 * Note: This class is abstract to be subclassed for both client and server tests.
 */
class TLS_Context {
   protected:
      TLS_Context(std::shared_ptr<Botan::RandomNumberGenerator> rng_in,
                  std::shared_ptr<const RFC8448_Text_Policy> policy,
                  Modify_Exts_Fn modify_exts_cb,
                  std::vector<MockSignature> mock_signatures,
                  uint64_t timestamp,
                  std::optional<std::pair<Session, Session_Ticket>> session_and_ticket,
                  std::optional<ExternalPSK> external_psk,
                  bool use_alternative_server_certificate) :
            m_callbacks(std::make_shared<Test_TLS_13_Callbacks>(
               std::move(modify_exts_cb), std::move(mock_signatures), timestamp)),
            m_creds(std::make_shared<Test_Credentials>(use_alternative_server_certificate, std::move(external_psk))),
            m_rng(std::move(rng_in)),
            m_session_mgr(std::make_shared<RFC8448_Session_Manager>()),
            m_policy(std::move(policy)) {
         if(session_and_ticket.has_value()) {
            m_session_mgr->store(std::get<Session>(session_and_ticket.value()),
                                 Botan::TLS::Session_Handle(std::get<Session_Ticket>(session_and_ticket.value())));
         }
      }

   public:
      virtual ~TLS_Context() = default;

      TLS_Context(TLS_Context&) = delete;
      TLS_Context& operator=(const TLS_Context&) = delete;

      TLS_Context(TLS_Context&&) = delete;
      TLS_Context& operator=(TLS_Context&&) = delete;

      std::vector<uint8_t> pull_send_buffer() { return m_callbacks->pull_send_buffer(); }

      std::vector<uint8_t> pull_receive_buffer() { return m_callbacks->pull_receive_buffer(); }

      uint64_t last_received_seq_no() const { return m_callbacks->last_received_seq_no(); }

      /**
       * Checks that all of the listed callbacks were called at least once, no other
       * callbacks were called in addition to the expected ones. After the checks are
       * done, the callback invocation counters are reset.
       */
      void check_callback_invocations(Test::Result& result,
                                      const std::string& context,
                                      const std::vector<std::string>& callback_names) {
         const auto& invokes = m_callbacks->callback_invocations();
         for(const auto& cbn : callback_names) {
            result.test_is_true(Botan::fmt("{} was invoked (Context: {})", cbn, context),
                                invokes.contains(cbn) && invokes.at(cbn) > 0);
         }

         for(const auto& invoke : invokes) {
            if(invoke.second == 0) {
               continue;
            }
            result.test_is_true(
               invoke.first + " was expected (Context: " + context + ")",
               std::find(callback_names.cbegin(), callback_names.cend(), invoke.first) != callback_names.cend());
         }

         m_callbacks->reset_callback_invocation_counters();
      }

      const std::vector<Session_with_Handle>& stored_sessions() const { return m_session_mgr->all_sessions(); }

      const std::vector<Botan::X509_Certificate>& certs_verified() const { return m_callbacks->certificate_chain; }

      const std::string& psk_identity_negotiated() const { return m_callbacks->negotiated_psk_identity; }

      decltype(auto) observed_handshake_messages() const { return m_callbacks->serialized_messages; }

      /**
       * Send application data through the secure channel
       */
      virtual void send(const std::vector<uint8_t>& data) = 0;

   protected:
      std::shared_ptr<Test_TLS_13_Callbacks> m_callbacks;  // NOLINT(*-non-private-member-variable*)
      std::shared_ptr<Test_Credentials> m_creds;           // NOLINT(*-non-private-member-variable*)

      std::shared_ptr<Botan::RandomNumberGenerator> m_rng;     // NOLINT(*-non-private-member-variable*)
      std::shared_ptr<RFC8448_Session_Manager> m_session_mgr;  // NOLINT(*-non-private-member-variable*)
      std::shared_ptr<const RFC8448_Text_Policy> m_policy;     // NOLINT(*-non-private-member-variable*)
};

class Client_Context : public TLS_Context {
   public:
      Client_Context(std::shared_ptr<Botan::RandomNumberGenerator> rng_in,
                     std::shared_ptr<const RFC8448_Text_Policy> policy,
                     uint64_t timestamp,
                     Modify_Exts_Fn modify_exts_cb,
                     std::optional<std::pair<Session, Session_Ticket>> session_and_ticket = std::nullopt,
                     std::optional<ExternalPSK> external_psk = std::nullopt,
                     std::vector<MockSignature> mock_signatures = {}) :
            TLS_Context(std::move(rng_in),
                        std::move(policy),
                        std::move(modify_exts_cb),
                        std::move(mock_signatures),
                        timestamp,
                        std::move(session_and_ticket),
                        std::move(external_psk),
                        false),
            client(m_callbacks,
                   m_session_mgr,
                   m_creds,
                   m_policy,
                   m_rng,
                   Botan::TLS::Server_Information("server"),
                   Botan::TLS::Protocol_Version::TLS_V13) {}

      void send(const std::vector<uint8_t>& data) override { client.send(data.data(), data.size()); }

      Botan::TLS::Client client;  // NOLINT(*-non-private-member-variable*)
};

class Server_Context : public TLS_Context {
   public:
      Server_Context(std::shared_ptr<Botan::RandomNumberGenerator> rng,
                     std::shared_ptr<const RFC8448_Text_Policy> policy,
                     uint64_t timestamp,
                     Modify_Exts_Fn modify_exts_cb,
                     std::vector<MockSignature> mock_signatures,
                     bool use_alternative_server_certificate = false,
                     std::optional<std::pair<Session, Session_Ticket>> session_and_ticket = std::nullopt,
                     std::optional<ExternalPSK> external_psk = std::nullopt) :
            TLS_Context(std::move(rng),
                        std::move(policy),
                        std::move(modify_exts_cb),
                        std::move(mock_signatures),
                        timestamp,
                        std::move(session_and_ticket),
                        std::move(external_psk),
                        use_alternative_server_certificate),
            server(m_callbacks, m_session_mgr, m_creds, m_policy, m_rng, false /* DTLS NYI */) {}

      void send(const std::vector<uint8_t>& data) override { server.send(data.data(), data.size()); }

      Botan::TLS::Server server;  // NOLINT(*-non-private-member-variable*)
};

/**
 * Because of the nature of the RFC 8448 test data we need to produce bit-compatible
 * TLS messages. Hence we sort the generated TLS extensions exactly as expected.
 */
void sort_rfc8448_extensions(Botan::TLS::Extensions& exts,
                             Botan::TLS::Connection_Side side,
                             Botan::TLS::Handshake_Type /*type*/ = Botan::TLS::Handshake_Type::ClientHello) {
   if(side == Botan::TLS::Connection_Side::Client) {
      exts.reorder({
         Botan::TLS::Extension_Code::ServerNameIndication,
         Botan::TLS::Extension_Code::SafeRenegotiation,
         Botan::TLS::Extension_Code::SupportedGroups,
         Botan::TLS::Extension_Code::SessionTicket,
         Botan::TLS::Extension_Code::KeyShare,
         Botan::TLS::Extension_Code::EarlyData,
         Botan::TLS::Extension_Code::SupportedVersions,
         Botan::TLS::Extension_Code::SignatureAlgorithms,
         Botan::TLS::Extension_Code::Cookie,
         Botan::TLS::Extension_Code::PskKeyExchangeModes,
         Botan::TLS::Extension_Code::RecordSizeLimit,
         Padding::static_type(),
         Botan::TLS::Extension_Code::PresharedKey,
      });
   } else {
      exts.reorder({
         Botan::TLS::Extension_Code::SupportedGroups,
         Botan::TLS::Extension_Code::KeyShare,
         Botan::TLS::Extension_Code::Cookie,
         Botan::TLS::Extension_Code::SupportedVersions,
         Botan::TLS::Extension_Code::SignatureAlgorithms,
         Botan::TLS::Extension_Code::RecordSizeLimit,
         Botan::TLS::Extension_Code::ServerNameIndication,
         Botan::TLS::Extension_Code::EarlyData,
      });
   }
}

void add_renegotiation_extension(Botan::TLS::Extensions& exts) {
   // Renegotiation is not possible in TLS 1.3. Nevertheless, RFC 8448 requires
   // to add this to the Client Hello for reasons.
   exts.add(new Renegotiation_Extension());  // NOLINT(*-owning-memory)
}

void add_early_data_indication(Botan::TLS::Extensions& exts) {
   exts.add(new Botan::TLS::EarlyDataIndication());  // NOLINT(*-owning-memory)
}

std::vector<uint8_t> strip_message_header(const std::vector<uint8_t>& msg) {
   BOTAN_ASSERT_NOMSG(msg.size() >= 4);
   return {msg.begin() + 4, msg.end()};
}

std::vector<MockSignature> make_mock_signatures(const VarMap& vars) {
   std::vector<MockSignature> result;

   auto mock = [&](const std::string& msg, const std::string& sig) {
      if(vars.has_key(msg) && vars.has_key(sig)) {
         result.push_back({vars.get_opt_bin(msg), vars.get_opt_bin(sig)});
      }
   };

   mock("Server_MessageToSign", "Server_MessageSignature");
   mock("Client_MessageToSign", "Client_MessageSignature");

   return result;
}

/**
 * Traffic transcripts and supporting data for the TLS RFC 8448 and TLS policy
 * configuration is kept in data files (accessible via `Test:::data_file()`).
 *
 * tls_13_rfc8448/transcripts.vec
 *   The record transcripts and RNG outputs as defined/required in RFC 8448 in
 *   Botan's Text_Based_Test vector format. Data from each RFC 8448 section is
 *   placed in a sub-section of the *.vec file. Each of those sections needs a
 *   specific test case implementation that is dispatched in `run_one_test()`.
 *
 * tls_13_rfc8448/client_certificate.pem
 *   The client certificate provided in RFC 8448 used to perform client auth.
 *   Note that RFC 8448 _does not_ provide the associated private key but only
 *   the resulting signature in the client's CertificateVerify message.
 *
 * tls_13_rfc8448/server_certificate.pem
 * tls_13_rfc8448/server_key.pem
 *   The server certificate and its associated private key.
 *
 * tls_13_rfc8448/server_certificate_client_auth.pem
 *   The server certificate used in the Client Authentication test case.
 *
 * tls_13_rfc8448/client_raw_public_keypair.pem
 * tls_13_rfc8448/server_raw_public_keypair.pem
 *   The raw public key pairs for client and server authentication in the
 *   equally named test cases.
 *
 * tls-policy/rfc8448_*.txt
 *   Each RFC 8448 section test required a slightly adapted Botan TLS policy
 *   to enable/disable certain features under test.
 *
 * While the test cases are split into Client-side and Server-side tests, the
 * transcript data is reused. See the concrete implementations of the abstract
 * Test_TLS_RFC8448 test class.
 */
class Test_TLS_RFC8448 : public Text_Based_Test {
   protected:
      // Those tests are based on the test vectors in RFC8448.
      virtual std::vector<Test::Result> simple_1_rtt(const VarMap& vars) = 0;
      virtual std::vector<Test::Result> resumed_handshake_with_0_rtt(const VarMap& vars) = 0;
      virtual std::vector<Test::Result> hello_retry_request(const VarMap& vars) = 0;
      virtual std::vector<Test::Result> client_authentication(const VarMap& vars) = 0;
      virtual std::vector<Test::Result> middlebox_compatibility(const VarMap& vars) = 0;

      // Those tests provide the same information as RFC8448 test vectors but
      // were sourced otherwise. Typically by temporarily instrumenting our implementation.
      virtual std::vector<Test::Result> externally_provided_psk_with_ephemeral_key(const VarMap& vars) = 0;
      virtual std::vector<Test::Result> raw_public_key_with_client_authentication(const VarMap& vars) = 0;

      virtual std::string side() const = 0;

   public:
      Test_TLS_RFC8448() :
            Text_Based_Test("tls_13_rfc8448/transcripts.vec",
                            // mandatory data fields
                            "Client_RNG_Pool,"
                            "Server_RNG_Pool,"
                            "CurrentTimestamp,"
                            "Record_ClientHello_1,"
                            "Record_ServerHello,"
                            "Record_ServerHandshakeMessages,"
                            "Record_ClientFinished,"
                            "Record_Client_CloseNotify,"
                            "Record_Server_CloseNotify",
                            // optional data fields
                            "Message_ServerHello,"
                            "Message_EncryptedExtensions,"
                            "Message_CertificateRequest,"
                            "Message_Server_Certificate,"
                            "Message_Server_CertificateVerify,"
                            "Message_Server_Finished,"
                            "Record_HelloRetryRequest,"
                            "Record_ClientHello_2,"
                            "Record_NewSessionTicket,"
                            "Client_AppData,"
                            "Record_Client_AppData,"
                            "Server_AppData,"
                            "Record_Server_AppData,"
                            "Client_EarlyAppData,"
                            "Record_Client_EarlyAppData,"
                            "SessionTicket,"
                            "Client_SessionData,"
                            "Server_MessageToSign,"
                            "Server_MessageSignature,"
                            "Client_MessageToSign,"
                            "Client_MessageSignature,"
                            "HelloRetryRequest_Cookie,"
                            "PskIdentity,"
                            "PskPRF,"
                            "PskSecret") {}

      Test::Result run_one_test(const std::string& header, const VarMap& vars) override {
         if(header == "Simple_1RTT_Handshake") {
            return Test::Result("Simple 1-RTT (" + side() + " side)", simple_1_rtt(vars));
         } else if(header == "Resumed_0RTT_Handshake") {
            return Test::Result("Resumption with 0-RTT data (" + side() + " side)", resumed_handshake_with_0_rtt(vars));
         } else if(header == "HelloRetryRequest_Handshake") {
            return Test::Result("Handshake involving Hello Retry Request (" + side() + " side)",
                                hello_retry_request(vars));
         } else if(header == "Client_Authentication_Handshake") {
            return Test::Result("Client Authentication (" + side() + " side)", client_authentication(vars));
         } else if(header == "Middlebox_Compatibility_Mode") {
            return Test::Result("Middlebox Compatibility Mode (" + side() + " side)", middlebox_compatibility(vars));
         } else if(header == "Externally_Provided_PSK_with_Ephemeral_Key") {
            return Test::Result("Externally Provided PSK with ephemeral key (" + side() + " side)",
                                externally_provided_psk_with_ephemeral_key(vars));
         } else if(header == "RawPublicKey_With_Client_Authentication") {
            return Test::Result("RawPublicKey with Client Authentication (" + side() + " side)",
                                raw_public_key_with_client_authentication(vars));
         } else {
            return Test::Result::Failure("test dispatcher", "unknown sub-test: " + header);
         }
      }
};

class Test_TLS_RFC8448_Client : public Test_TLS_RFC8448 {
   private:
      std::string side() const override { return "Client"; }

      std::vector<Test::Result> simple_1_rtt(const VarMap& vars) override {
         auto rng = std::make_shared<Fixed_Output_RNG>("");

         // 32 - for client hello random
         // 32 - for KeyShare (eph. x25519 key pair)
         add_entropy(*rng, vars.get_req_bin("Client_RNG_Pool"));

         auto add_extensions_and_sort = [](Botan::TLS::Extensions& exts,
                                           Botan::TLS::Connection_Side side,
                                           Botan::TLS::Handshake_Type which_message) {
            if(which_message == Handshake_Type::ClientHello) {
               // For some reason, presumably checking compatibility, the RFC 8448 Client
               // Hello includes a (TLS 1.2) Session_Ticket extension. We don't normally add
               // this obsoleted extension in a TLS 1.3 client.
               exts.add(new Botan::TLS::Session_Ticket_Extension());  // NOLINT(*-owning-memory)

               add_renegotiation_extension(exts);
               sort_rfc8448_extensions(exts, side);
            }
         };

         std::unique_ptr<Client_Context> ctx;

         return {
            CHECK("Client Hello",
                  [&](Test::Result& result) {
                     ctx = std::make_unique<Client_Context>(rng,
                                                            std::make_shared<RFC8448_Text_Policy>("rfc8448_1rtt"),
                                                            vars.get_req_u64("CurrentTimestamp"),
                                                            add_extensions_and_sort);

                     result.test_is_true("client not closed", !ctx->client.is_closed());
                     ctx->check_callback_invocations(result,
                                                     "client hello prepared",
                                                     {
                                                        "tls_emit_data",
                                                        "tls_inspect_handshake_msg_client_hello",
                                                        "tls_modify_extensions_client_hello",
                                                        "tls_generate_ephemeral_key",
                                                        "tls_current_timestamp",
                                                     });

                     result.test_bin_eq(
                        "TLS client hello", ctx->pull_send_buffer(), vars.get_req_bin("Record_ClientHello_1"));
                  }),

            CHECK("Server Hello",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     const auto server_hello = vars.get_req_bin("Record_ServerHello");
                     // splitting the input data to test partial reads
                     const std::vector<uint8_t> server_hello_a(server_hello.begin(), server_hello.begin() + 20);
                     const std::vector<uint8_t> server_hello_b(server_hello.begin() + 20, server_hello.end());

                     ctx->client.received_data(server_hello_a);
                     ctx->check_callback_invocations(result, "server hello partially received", {});

                     ctx->client.received_data(server_hello_b);
                     ctx->check_callback_invocations(result,
                                                     "server hello received",
                                                     {"tls_inspect_handshake_msg_server_hello",
                                                      "tls_examine_extensions_server_hello",
                                                      "tls_ephemeral_key_agreement"});

                     result.test_is_true("client is not yet active", !ctx->client.is_active());
                     result.test_is_true("handshake is not yet complete", !ctx->client.is_handshake_complete());
                  }),

            CHECK("Server HS messages .. Client Finished",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.received_data(vars.get_req_bin("Record_ServerHandshakeMessages"));

                     ctx->check_callback_invocations(result,
                                                     "encrypted handshake messages received",
                                                     {"tls_inspect_handshake_msg_encrypted_extensions",
                                                      "tls_inspect_handshake_msg_certificate",
                                                      "tls_inspect_handshake_msg_certificate_verify",
                                                      "tls_inspect_handshake_msg_finished",
                                                      "tls_examine_extensions_encrypted_extensions",
                                                      "tls_examine_extensions_certificate",
                                                      "tls_emit_data",
                                                      "tls_current_timestamp",
                                                      "tls_session_established",
                                                      "tls_session_activated",
                                                      "tls_verify_cert_chain",
                                                      "tls_verify_message"});
                     result.require("certificate exists", !ctx->certs_verified().empty());
                     result.require("correct certificate", ctx->certs_verified().front() == server_certificate());
                     result.require("client is active", ctx->client.is_active());
                     result.test_is_true("handshake is complete", ctx->client.is_handshake_complete());

                     result.test_bin_eq("correct handshake finished",
                                        ctx->pull_send_buffer(),
                                        vars.get_req_bin("Record_ClientFinished"));
                  }),

            CHECK("Post-Handshake: NewSessionTicket",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     result.require("no sessions so far", ctx->stored_sessions().empty());
                     ctx->client.received_data(vars.get_req_bin("Record_NewSessionTicket"));

                     ctx->check_callback_invocations(result,
                                                     "new session ticket received",
                                                     {"tls_examine_extensions_new_session_ticket",
                                                      "tls_should_persist_resumption_information",
                                                      "tls_current_timestamp"});
                     if(result.test_sz_eq("session was stored", ctx->stored_sessions().size(), 1)) {
                        const auto& [stored_session, stored_handle] = ctx->stored_sessions().front();
                        result.require("session handle contains a ticket", stored_handle.ticket().has_value());
                        result.test_bin_eq("session was serialized as expected",
                                           stored_session.DER_encode(),
                                           vars.get_req_bin("Client_SessionData"));
                     }
                  }),

            CHECK("Send Application Data",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->send(vars.get_req_bin("Client_AppData"));

                     ctx->check_callback_invocations(result, "application data sent", {"tls_emit_data"});

                     result.test_bin_eq("correct client application data",
                                        ctx->pull_send_buffer(),
                                        vars.get_req_bin("Record_Client_AppData"));
                  }),

            CHECK("Receive Application Data",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.received_data(vars.get_req_bin("Record_Server_AppData"));

                     ctx->check_callback_invocations(result, "application data sent", {"tls_record_received"});

                     const auto rcvd = ctx->pull_receive_buffer();
                     result.test_bin_eq("decrypted application traffic", rcvd, vars.get_req_bin("Server_AppData"));
                     result.test_u64_eq("sequence number", ctx->last_received_seq_no(), uint64_t(1));
                  }),

            CHECK("Close Connection",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.close();

                     result.test_bin_eq(
                        "close payload", ctx->pull_send_buffer(), vars.get_req_bin("Record_Client_CloseNotify"));
                     ctx->check_callback_invocations(result, "CLOSE_NOTIFY sent", {"tls_emit_data"});

                     ctx->client.received_data(vars.get_req_bin("Record_Server_CloseNotify"));
                     ctx->check_callback_invocations(
                        result, "CLOSE_NOTIFY received", {"tls_alert", "tls_peer_closed_connection"});

                     result.test_is_true("connection is closed", ctx->client.is_closed());
                  }),
         };
      }

      std::vector<Test::Result> resumed_handshake_with_0_rtt(const VarMap& vars) override {
         auto rng = std::make_unique<Fixed_Output_RNG>("");

         // 32 - for client hello random
         // 32 - for KeyShare (eph. x25519 key pair)
         add_entropy(*rng, vars.get_req_bin("Client_RNG_Pool"));

         auto add_extensions_and_sort = [](Botan::TLS::Extensions& exts,
                                           Botan::TLS::Connection_Side side,
                                           Botan::TLS::Handshake_Type which_message) {
            if(which_message == Handshake_Type::ClientHello) {
               exts.add(new Padding(87));  // NOLINT(*-owning-memory)

               add_renegotiation_extension(exts);

               // TODO: Implement early data support and remove this 'hack'.
               //
               // Currently, the production implementation will never add this
               // extension even if the resumed session would allow early data.
               add_early_data_indication(exts);
               sort_rfc8448_extensions(exts, side);
            }
         };

         std::unique_ptr<Client_Context> ctx;

         return {
            CHECK("Client Hello",
                  [&](Test::Result& result) {
                     ctx = std::make_unique<Client_Context>(
                        std::move(rng),
                        std::make_shared<RFC8448_Text_Policy>("rfc8448_1rtt"),
                        vars.get_req_u64("CurrentTimestamp"),
                        add_extensions_and_sort,
                        std::pair{Botan::TLS::Session(vars.get_req_bin("Client_SessionData")),
                                  Botan::TLS::Session_Ticket(vars.get_req_bin("SessionTicket"))});

                     result.test_is_true("client not closed", !ctx->client.is_closed());
                     ctx->check_callback_invocations(result,
                                                     "client hello prepared",
                                                     {
                                                        "tls_emit_data",
                                                        "tls_inspect_handshake_msg_client_hello",
                                                        "tls_modify_extensions_client_hello",
                                                        "tls_current_timestamp",
                                                        "tls_generate_ephemeral_key",
                                                     });

                     result.test_bin_eq(
                        "TLS client hello", ctx->pull_send_buffer(), vars.get_req_bin("Record_ClientHello_1"));
                  })

            // TODO: The rest of this test vector requires 0-RTT which is not
            //       yet implemented. For now we can only test the client's
            //       ability to offer a session resumption via PSK.
         };
      }

      std::vector<Test::Result> hello_retry_request(const VarMap& vars) override {
         auto add_extensions_and_sort = [flights = 0](Botan::TLS::Extensions& exts,
                                                      Botan::TLS::Connection_Side side,
                                                      Botan::TLS::Handshake_Type which_message) mutable {
            if(which_message == Handshake_Type::ClientHello) {
               ++flights;

               if(flights == 1) {
                  add_renegotiation_extension(exts);
               }

               // For some reason RFC8448 decided to require this (fairly obscure) extension
               // in the second flight of the Client_Hello.
               if(flights == 2) {
                  exts.add(new Padding(175));  // NOLINT(*-owning-memory)
               }

               sort_rfc8448_extensions(exts, side);
            }
         };

         // Fallback RNG is required to for blinding in ECDH with P-256
         auto& fallback_rng = this->rng();
         auto rng = std::make_unique<Fixed_Output_RNG>(fallback_rng);

         // 32 - client hello random
         // 32 - eph. x25519 key pair
         // 32 - eph. P-256 key pair
         add_entropy(*rng, vars.get_req_bin("Client_RNG_Pool"));

         std::unique_ptr<Client_Context> ctx;

         return {
            CHECK("Client Hello",
                  [&](Test::Result& result) {
                     ctx = std::make_unique<Client_Context>(std::move(rng),
                                                            std::make_shared<RFC8448_Text_Policy>("rfc8448_hrr_client"),
                                                            vars.get_req_u64("CurrentTimestamp"),
                                                            add_extensions_and_sort);
                     result.test_is_true("client not closed", !ctx->client.is_closed());

                     ctx->check_callback_invocations(result,
                                                     "client hello prepared",
                                                     {
                                                        "tls_emit_data",
                                                        "tls_inspect_handshake_msg_client_hello",
                                                        "tls_modify_extensions_client_hello",
                                                        "tls_generate_ephemeral_key",
                                                        "tls_current_timestamp",
                                                     });

                     result.test_bin_eq(
                        "TLS client hello (1)", ctx->pull_send_buffer(), vars.get_req_bin("Record_ClientHello_1"));
                  }),

            CHECK("Hello Retry Request .. second Client Hello",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.received_data(vars.get_req_bin("Record_HelloRetryRequest"));

                     ctx->check_callback_invocations(result,
                                                     "hello retry request received",
                                                     {
                                                        "tls_emit_data",
                                                        "tls_inspect_handshake_msg_hello_retry_request",
                                                        "tls_examine_extensions_hello_retry_request",
                                                        "tls_inspect_handshake_msg_client_hello",
                                                        "tls_modify_extensions_client_hello",
                                                        "tls_generate_ephemeral_key",
                                                     });

                     result.test_bin_eq(
                        "TLS client hello (2)", ctx->pull_send_buffer(), vars.get_req_bin("Record_ClientHello_2"));
                  }),

            CHECK("Server Hello",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.received_data(vars.get_req_bin("Record_ServerHello"));

                     ctx->check_callback_invocations(result,
                                                     "server hello received",
                                                     {
                                                        "tls_inspect_handshake_msg_server_hello",
                                                        "tls_examine_extensions_server_hello",
                                                        "tls_ephemeral_key_agreement",
                                                     });
                  }),

            CHECK("Server HS Messages .. Client Finished",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.received_data(vars.get_req_bin("Record_ServerHandshakeMessages"));

                     ctx->check_callback_invocations(result,
                                                     "encrypted handshake messages received",
                                                     {"tls_inspect_handshake_msg_encrypted_extensions",
                                                      "tls_inspect_handshake_msg_certificate",
                                                      "tls_inspect_handshake_msg_certificate_verify",
                                                      "tls_inspect_handshake_msg_finished",
                                                      "tls_examine_extensions_encrypted_extensions",
                                                      "tls_examine_extensions_certificate",
                                                      "tls_emit_data",
                                                      "tls_current_timestamp",
                                                      "tls_session_established",
                                                      "tls_session_activated",
                                                      "tls_verify_cert_chain",
                                                      "tls_verify_message"});

                     result.test_bin_eq(
                        "client finished", ctx->pull_send_buffer(), vars.get_req_bin("Record_ClientFinished"));
                  }),

            CHECK("Close Connection",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.close();
                     ctx->check_callback_invocations(
                        result, "encrypted handshake messages received", {"tls_emit_data"});
                     result.test_bin_eq(
                        "client close notify", ctx->pull_send_buffer(), vars.get_req_bin("Record_Client_CloseNotify"));

                     ctx->client.received_data(vars.get_req_bin("Record_Server_CloseNotify"));
                     ctx->check_callback_invocations(
                        result, "encrypted handshake messages received", {"tls_alert", "tls_peer_closed_connection"});

                     result.test_is_true("connection is closed", ctx->client.is_closed());
                  }),
         };
      }

      std::vector<Test::Result> client_authentication(const VarMap& vars) override {
         auto rng = std::make_unique<Fixed_Output_RNG>("");

         // 32 - for client hello random
         // 32 - for eph. x25519 key pair
         add_entropy(*rng, vars.get_req_bin("Client_RNG_Pool"));

         auto add_extensions_and_sort = [&](Botan::TLS::Extensions& exts,
                                            Botan::TLS::Connection_Side side,
                                            Botan::TLS::Handshake_Type which_message) {
            if(which_message == Handshake_Type::ClientHello) {
               add_renegotiation_extension(exts);
               sort_rfc8448_extensions(exts, side);
            }
         };

         std::unique_ptr<Client_Context> ctx;

         return {
            CHECK("Client Hello",
                  [&](Test::Result& result) {
                     ctx = std::make_unique<Client_Context>(std::move(rng),
                                                            std::make_shared<RFC8448_Text_Policy>("rfc8448_1rtt"),
                                                            vars.get_req_u64("CurrentTimestamp"),
                                                            add_extensions_and_sort,
                                                            std::nullopt,
                                                            std::nullopt,
                                                            make_mock_signatures(vars));

                     ctx->check_callback_invocations(result,
                                                     "initial callbacks",
                                                     {
                                                        "tls_emit_data",
                                                        "tls_inspect_handshake_msg_client_hello",
                                                        "tls_modify_extensions_client_hello",
                                                        "tls_generate_ephemeral_key",
                                                        "tls_current_timestamp",
                                                     });

                     result.test_bin_eq(
                        "Client Hello", ctx->pull_send_buffer(), vars.get_req_bin("Record_ClientHello_1"));
                  }),

            CHECK("Server Hello",
                  [&](auto& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.received_data(vars.get_req_bin("Record_ServerHello"));

                     ctx->check_callback_invocations(result,
                                                     "callbacks after server hello",
                                                     {
                                                        "tls_examine_extensions_server_hello",
                                                        "tls_inspect_handshake_msg_server_hello",
                                                        "tls_ephemeral_key_agreement",
                                                     });
                  }),

            CHECK("other handshake messages and client auth",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.received_data(vars.get_req_bin("Record_ServerHandshakeMessages"));

                     ctx->check_callback_invocations(result,
                                                     "signing callbacks invoked",
                                                     {
                                                        "tls_sign_message",
                                                        "tls_emit_data",
                                                        "tls_examine_extensions_encrypted_extensions",
                                                        "tls_examine_extensions_certificate",
                                                        "tls_examine_extensions_certificate_request",
                                                        "tls_modify_extensions_certificate",
                                                        "tls_inspect_handshake_msg_certificate",
                                                        "tls_inspect_handshake_msg_certificate_request",
                                                        "tls_inspect_handshake_msg_certificate_verify",
                                                        "tls_inspect_handshake_msg_encrypted_extensions",
                                                        "tls_inspect_handshake_msg_finished",
                                                        "tls_current_timestamp",
                                                        "tls_session_established",
                                                        "tls_session_activated",
                                                        "tls_verify_cert_chain",
                                                        "tls_verify_message",
                                                     });

                     // ClientFinished contains the entire coalesced client authentication flight
                     // Messages: Certificate, CertificateVerify, Finished
                     result.test_bin_eq(
                        "Client Auth and Finished", ctx->pull_send_buffer(), vars.get_req_bin("Record_ClientFinished"));
                  }),

            CHECK("Close Connection",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.close();
                     result.test_bin_eq(
                        "Client close_notify", ctx->pull_send_buffer(), vars.get_req_bin("Record_Client_CloseNotify"));

                     ctx->check_callback_invocations(result,
                                                     "after sending close notify",
                                                     {
                                                        "tls_emit_data",
                                                     });

                     ctx->client.received_data(vars.get_req_bin("Record_Server_CloseNotify"));
                     result.test_is_true("connection closed", ctx->client.is_closed());

                     ctx->check_callback_invocations(
                        result, "after receiving close notify", {"tls_alert", "tls_peer_closed_connection"});
                  }),
         };
      }

      std::vector<Test::Result> middlebox_compatibility(const VarMap& vars) override {
         auto rng = std::make_unique<Fixed_Output_RNG>("");

         // 32 - client hello random
         // 32 - legacy session ID
         // 32 - eph. x25519 key pair
         add_entropy(*rng, vars.get_req_bin("Client_RNG_Pool"));

         auto add_extensions_and_sort = [&](Botan::TLS::Extensions& exts,
                                            Botan::TLS::Connection_Side side,
                                            Botan::TLS::Handshake_Type which_message) {
            if(which_message == Handshake_Type::ClientHello) {
               add_renegotiation_extension(exts);
               sort_rfc8448_extensions(exts, side);
            }
         };

         std::unique_ptr<Client_Context> ctx;

         return {
            CHECK(
               "Client Hello",
               [&](Test::Result& result) {
                  ctx = std::make_unique<Client_Context>(std::move(rng),
                                                         std::make_shared<RFC8448_Text_Policy>("rfc8448_compat_client"),
                                                         vars.get_req_u64("CurrentTimestamp"),
                                                         add_extensions_and_sort);

                  result.test_bin_eq("Client Hello", ctx->pull_send_buffer(), vars.get_req_bin("Record_ClientHello_1"));

                  ctx->check_callback_invocations(result,
                                                  "client hello prepared",
                                                  {
                                                     "tls_emit_data",
                                                     "tls_inspect_handshake_msg_client_hello",
                                                     "tls_modify_extensions_client_hello",
                                                     "tls_generate_ephemeral_key",
                                                     "tls_current_timestamp",
                                                  });
               }),

            CHECK("Server Hello + other handshake messages",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.received_data(
                        Botan::concat(vars.get_req_bin("Record_ServerHello"),
                                      // ServerHandshakeMessages contains the expected ChangeCipherSpec record
                                      vars.get_req_bin("Record_ServerHandshakeMessages")));

                     ctx->check_callback_invocations(result,
                                                     "callbacks after server's first flight",
                                                     {
                                                        "tls_inspect_handshake_msg_server_hello",
                                                        "tls_inspect_handshake_msg_encrypted_extensions",
                                                        "tls_inspect_handshake_msg_certificate",
                                                        "tls_inspect_handshake_msg_certificate_verify",
                                                        "tls_inspect_handshake_msg_finished",
                                                        "tls_examine_extensions_server_hello",
                                                        "tls_examine_extensions_encrypted_extensions",
                                                        "tls_examine_extensions_certificate",
                                                        "tls_emit_data",
                                                        "tls_current_timestamp",
                                                        "tls_session_established",
                                                        "tls_session_activated",
                                                        "tls_verify_cert_chain",
                                                        "tls_verify_message",
                                                        "tls_ephemeral_key_agreement",
                                                     });

                     result.test_bin_eq("CCS + Client Finished",
                                        ctx->pull_send_buffer(),
                                        // ClientFinished contains the expected ChangeCipherSpec record
                                        vars.get_req_bin("Record_ClientFinished"));

                     result.test_is_true("client is ready to send application traffic", ctx->client.is_active());
                     result.test_is_true("handshake is complete", ctx->client.is_handshake_complete());
                  }),

            CHECK("Close connection",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.close();

                     result.test_bin_eq(
                        "Client close_notify", ctx->pull_send_buffer(), vars.get_req_bin("Record_Client_CloseNotify"));

                     result.require("client cannot send application traffic anymore", !ctx->client.is_active());
                     result.require("client is not fully closed yet", !ctx->client.is_closed());
                     result.test_is_true("handshake stays completed", ctx->client.is_handshake_complete());

                     ctx->client.received_data(vars.get_req_bin("Record_Server_CloseNotify"));

                     result.test_is_true("client connection was terminated", ctx->client.is_closed());
                  }),
         };
      }

      std::vector<Test::Result> externally_provided_psk_with_ephemeral_key(const VarMap& vars) override {
         auto rng = std::make_unique<Fixed_Output_RNG>("");

         // 32 - for client hello random
         // 32 - for KeyShare (eph. x25519 key pair)
         add_entropy(*rng, vars.get_req_bin("Client_RNG_Pool"));

         auto sort_our_extensions = [](Botan::TLS::Extensions& exts,
                                       Botan::TLS::Connection_Side /* side */,
                                       Botan::TLS::Handshake_Type /* which_message */) {
            // This is the order of extensions when we first introduced the PSK
            // implementation and generated the transcript. To stay compatible
            // with the now hard-coded transcript, we pin the extension order.
            exts.reorder({
               Botan::TLS::Extension_Code::ServerNameIndication,
               Botan::TLS::Extension_Code::SupportedGroups,
               Botan::TLS::Extension_Code::KeyShare,
               Botan::TLS::Extension_Code::SupportedVersions,
               Botan::TLS::Extension_Code::SignatureAlgorithms,
               Botan::TLS::Extension_Code::PskKeyExchangeModes,
               Botan::TLS::Extension_Code::RecordSizeLimit,
               Botan::TLS::Extension_Code::PresharedKey,
            });
         };

         std::unique_ptr<Client_Context> ctx;

         return {
            CHECK("Client Hello",
                  [&](Test::Result& result) {
                     ctx = std::make_unique<Client_Context>(
                        std::move(rng),
                        std::make_shared<RFC8448_Text_Policy>("rfc8448_psk_dhe", false /* no rfc8448 */),
                        vars.get_req_u64("CurrentTimestamp"),
                        sort_our_extensions,
                        std::nullopt,
                        ExternalPSK(vars.get_req_str("PskIdentity"),
                                    vars.get_req_str("PskPRF"),
                                    lock(vars.get_req_bin("PskSecret"))));

                     result.test_is_true("client not closed", !ctx->client.is_closed());
                     ctx->check_callback_invocations(result,
                                                     "client hello prepared",
                                                     {
                                                        "tls_emit_data",
                                                        "tls_inspect_handshake_msg_client_hello",
                                                        "tls_modify_extensions_client_hello",
                                                        "tls_current_timestamp",
                                                        "tls_generate_ephemeral_key",
                                                     });

                     result.test_bin_eq(
                        "TLS client hello", ctx->pull_send_buffer(), vars.get_req_bin("Record_ClientHello_1"));
                  }),

            CHECK("Server Hello",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     const auto server_hello = vars.get_req_bin("Record_ServerHello");
                     ctx->client.received_data(server_hello);
                     ctx->check_callback_invocations(result,
                                                     "server hello received",
                                                     {"tls_inspect_handshake_msg_server_hello",
                                                      "tls_examine_extensions_server_hello",
                                                      "tls_ephemeral_key_agreement"});

                     result.test_is_true("client is not yet active", !ctx->client.is_active());
                     result.test_is_true("handshake is not yet complete", !ctx->client.is_handshake_complete());
                  }),

            CHECK(
               "Server HS messages .. Client Finished",
               [&](Test::Result& result) {
                  result.require("ctx is available", ctx != nullptr);
                  ctx->client.received_data(vars.get_req_bin("Record_ServerHandshakeMessages"));

                  ctx->check_callback_invocations(result,
                                                  "encrypted handshake messages received",
                                                  {"tls_inspect_handshake_msg_encrypted_extensions",
                                                   "tls_inspect_handshake_msg_finished",
                                                   "tls_examine_extensions_encrypted_extensions",
                                                   "tls_emit_data",
                                                   "tls_current_timestamp",
                                                   "tls_session_established",
                                                   "tls_session_activated"});
                  result.require("PSK negotiated", ctx->psk_identity_negotiated() == vars.get_req_str("PskIdentity"));
                  result.require("client is active", ctx->client.is_active());
                  result.test_is_true("handshake is complete", ctx->client.is_handshake_complete());

                  result.test_bin_eq(
                     "correct handshake finished", ctx->pull_send_buffer(), vars.get_req_bin("Record_ClientFinished"));
               }),

            CHECK("Send Application Data",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->send(vars.get_req_bin("Client_AppData"));

                     ctx->check_callback_invocations(result, "application data sent", {"tls_emit_data"});

                     result.test_bin_eq("correct client application data",
                                        ctx->pull_send_buffer(),
                                        vars.get_req_bin("Record_Client_AppData"));
                  }),

            CHECK("Receive Application Data",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.received_data(vars.get_req_bin("Record_Server_AppData"));

                     ctx->check_callback_invocations(result, "application data sent", {"tls_record_received"});

                     const auto rcvd = ctx->pull_receive_buffer();
                     result.test_bin_eq("decrypted application traffic", rcvd, vars.get_req_bin("Server_AppData"));
                     result.test_u64_eq("sequence number", ctx->last_received_seq_no(), uint64_t(0));
                  }),

            CHECK("Close Connection",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.close();

                     result.test_bin_eq(
                        "close payload", ctx->pull_send_buffer(), vars.get_req_bin("Record_Client_CloseNotify"));
                     ctx->check_callback_invocations(result, "CLOSE_NOTIFY sent", {"tls_emit_data"});

                     ctx->client.received_data(vars.get_req_bin("Record_Server_CloseNotify"));
                     ctx->check_callback_invocations(
                        result, "CLOSE_NOTIFY received", {"tls_alert", "tls_peer_closed_connection"});

                     result.test_is_true("connection is closed", ctx->client.is_closed());
                  }),
         };
      }

      std::vector<Test::Result> raw_public_key_with_client_authentication(const VarMap& vars) override {
         auto rng = std::make_unique<Fixed_Output_RNG>("");

         // 32 - for client hello random
         // 32 - for KeyShare (eph. x25519 key pair)
         add_entropy(*rng, vars.get_req_bin("Client_RNG_Pool"));

         auto sort_our_extensions = [&](Botan::TLS::Extensions& exts,
                                        Botan::TLS::Connection_Side /* side */,
                                        Botan::TLS::Handshake_Type /* which_message */) {
            // This is the order of extensions when we first introduced the raw
            // public key authentication implementation and generated the transcript.
            // To stay compatible with the now hard-coded transcript, we pin the
            // extension order.
            exts.reorder({
               Botan::TLS::Extension_Code::ServerNameIndication,
               Botan::TLS::Extension_Code::SupportedGroups,
               Botan::TLS::Extension_Code::KeyShare,
               Botan::TLS::Extension_Code::SupportedVersions,
               Botan::TLS::Extension_Code::SignatureAlgorithms,
               Botan::TLS::Extension_Code::PskKeyExchangeModes,
               Botan::TLS::Extension_Code::RecordSizeLimit,
               Botan::TLS::Extension_Code::ClientCertificateType,
               Botan::TLS::Extension_Code::ServerCertificateType,
            });
         };

         std::unique_ptr<Client_Context> ctx;

         return {
            CHECK("Client Hello",
                  [&](Test::Result& result) {
                     ctx = std::make_unique<Client_Context>(std::move(rng),
                                                            std::make_shared<RFC8448_Text_Policy>("rfc8448_rawpubkey"),
                                                            vars.get_req_u64("CurrentTimestamp"),
                                                            sort_our_extensions,
                                                            std::nullopt,
                                                            std::nullopt,
                                                            make_mock_signatures(vars));

                     ctx->check_callback_invocations(result,
                                                     "initial callbacks",
                                                     {
                                                        "tls_emit_data",
                                                        "tls_inspect_handshake_msg_client_hello",
                                                        "tls_modify_extensions_client_hello",
                                                        "tls_generate_ephemeral_key",
                                                        "tls_current_timestamp",
                                                     });

                     result.test_bin_eq(
                        "Client Hello", ctx->pull_send_buffer(), vars.get_req_bin("Record_ClientHello_1"));
                  }),

            CHECK("Server Hello",
                  [&](auto& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.received_data(vars.get_req_bin("Record_ServerHello"));

                     ctx->check_callback_invocations(result,
                                                     "callbacks after server hello",
                                                     {
                                                        "tls_examine_extensions_server_hello",
                                                        "tls_inspect_handshake_msg_server_hello",
                                                        "tls_ephemeral_key_agreement",
                                                     });
                  }),

            CHECK("other handshake messages and client auth",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.received_data(vars.get_req_bin("Record_ServerHandshakeMessages"));

                     ctx->check_callback_invocations(result,
                                                     "signing callbacks invoked",
                                                     {
                                                        "tls_sign_message",
                                                        "tls_emit_data",
                                                        "tls_examine_extensions_encrypted_extensions",
                                                        "tls_examine_extensions_certificate",
                                                        "tls_examine_extensions_certificate_request",
                                                        "tls_modify_extensions_certificate",
                                                        "tls_inspect_handshake_msg_certificate",
                                                        "tls_inspect_handshake_msg_certificate_request",
                                                        "tls_inspect_handshake_msg_certificate_verify",
                                                        "tls_inspect_handshake_msg_encrypted_extensions",
                                                        "tls_inspect_handshake_msg_finished",
                                                        "tls_current_timestamp",
                                                        "tls_session_established",
                                                        "tls_session_activated",
                                                        "tls_verify_raw_public_key",
                                                        "tls_verify_message",
                                                     });

                     const auto raw_pk = ctx->client.peer_raw_public_key();
                     result.test_is_true(
                        "Received server's raw public key",
                        raw_pk && raw_pk->fingerprint_public() == server_raw_public_key_pair()->fingerprint_public());

                     // ClientFinished contains the entire coalesced client authentication flight
                     // Messages: Certificate, CertificateVerify, Finished
                     result.test_bin_eq(
                        "Client Auth and Finished", ctx->pull_send_buffer(), vars.get_req_bin("Record_ClientFinished"));
                  }),

            CHECK("Close Connection",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->client.close();
                     result.test_bin_eq(
                        "Client close_notify", ctx->pull_send_buffer(), vars.get_req_bin("Record_Client_CloseNotify"));

                     ctx->check_callback_invocations(result,
                                                     "after sending close notify",
                                                     {
                                                        "tls_emit_data",
                                                     });

                     ctx->client.received_data(vars.get_req_bin("Record_Server_CloseNotify"));
                     result.test_is_true("connection closed", ctx->client.is_closed());

                     ctx->check_callback_invocations(
                        result, "after receiving close notify", {"tls_alert", "tls_peer_closed_connection"});
                  }),
         };
      }
};

class Test_TLS_RFC8448_Server : public Test_TLS_RFC8448 {
   private:
      std::string side() const override { return "Server"; }

      std::vector<Test::Result> simple_1_rtt(const VarMap& vars) override {
         auto rng = std::make_unique<Fixed_Output_RNG>("");

         // 32 - for server hello random
         // 32 - for KeyShare (eph. x25519 key pair)  --  I guess?
         //  4 - for ticket_age_add (in New Session Ticket)
         add_entropy(*rng, vars.get_req_bin("Server_RNG_Pool"));

         std::unique_ptr<Server_Context> ctx;

         return {
            CHECK("Send Client Hello",
                  [&](Test::Result& result) {
                     auto add_early_data_and_sort = [&](Botan::TLS::Extensions& exts,
                                                        Botan::TLS::Connection_Side side,
                                                        Botan::TLS::Handshake_Type type) {
                        if(type == Handshake_Type::NewSessionTicket) {
                           exts.add(new EarlyDataIndication(1024));  // NOLINT(*-owning-memory)
                        }
                        sort_rfc8448_extensions(exts, side, type);
                     };

                     ctx = std::make_unique<Server_Context>(
                        std::move(rng),
                        std::make_shared<RFC8448_Text_Policy>("rfc8448_1rtt"),
                        vars.get_req_u64("CurrentTimestamp"),
                        add_early_data_and_sort,
                        make_mock_signatures(vars),
                        false,
                        std::pair{Botan::TLS::Session(vars.get_req_bin("Client_SessionData")),
                                  Botan::TLS::Session_Ticket(vars.get_req_bin("SessionTicket"))});
                     result.test_is_true("server not closed", !ctx->server.is_closed());

                     ctx->server.received_data(vars.get_req_bin("Record_ClientHello_1"));

                     ctx->check_callback_invocations(result,
                                                     "client hello received",
                                                     {"tls_emit_data",
                                                      "tls_examine_extensions_client_hello",
                                                      "tls_modify_extensions_server_hello",
                                                      "tls_modify_extensions_encrypted_extensions",
                                                      "tls_modify_extensions_certificate",
                                                      "tls_sign_message",
                                                      "tls_generate_ephemeral_key",
                                                      "tls_ephemeral_key_agreement",
                                                      "tls_inspect_handshake_msg_client_hello",
                                                      "tls_inspect_handshake_msg_server_hello",
                                                      "tls_inspect_handshake_msg_encrypted_extensions",
                                                      "tls_inspect_handshake_msg_certificate",
                                                      "tls_inspect_handshake_msg_certificate_verify",
                                                      "tls_inspect_handshake_msg_finished"});
                  }),

            CHECK("Verify generated messages in server's first flight",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     const auto& msgs = ctx->observed_handshake_messages();

                     result.test_bin_eq("Server Hello",
                                        msgs.at("server_hello")[0],
                                        strip_message_header(vars.get_opt_bin("Message_ServerHello")));
                     result.test_bin_eq("Encrypted Extensions",
                                        msgs.at("encrypted_extensions")[0],
                                        strip_message_header(vars.get_opt_bin("Message_EncryptedExtensions")));
                     result.test_bin_eq("Certificate",
                                        msgs.at("certificate")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_Certificate")));
                     result.test_bin_eq("CertificateVerify",
                                        msgs.at("certificate_verify")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_CertificateVerify")));

                     result.test_bin_eq("Server's entire first flight",
                                        ctx->pull_send_buffer(),
                                        concat(vars.get_req_bin("Record_ServerHello"),
                                               vars.get_req_bin("Record_ServerHandshakeMessages")));

                     // Note: is_active() defines that we can send application data.
                     //       RFC 8446 Section 4.4.4 explicitly allows that for servers
                     //       that did not receive the client's Finished message, yet.
                     //       However, before receiving and validating this message,
                     //       the handshake is not yet finished.
                     result.test_is_true("Server can now send application data", ctx->server.is_active());
                     result.test_is_true("handshake is not yet complete", !ctx->server.is_handshake_complete());
                  }),

            CHECK("Send Client Finished",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.received_data(vars.get_req_bin("Record_ClientFinished"));

                     ctx->check_callback_invocations(result,
                                                     "client finished received",
                                                     {"tls_inspect_handshake_msg_finished",
                                                      "tls_current_timestamp",
                                                      "tls_session_established",
                                                      "tls_session_activated"});
                  }),

            CHECK("Send Session Ticket",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     const auto new_tickets = ctx->server.send_new_session_tickets(1);

                     result.test_sz_eq("session ticket was sent", new_tickets, 1);

                     ctx->check_callback_invocations(result,
                                                     "issued new session ticket",
                                                     {"tls_inspect_handshake_msg_new_session_ticket",
                                                      "tls_current_timestamp",
                                                      "tls_emit_data",
                                                      "tls_modify_extensions_new_session_ticket",
                                                      "tls_should_persist_resumption_information"});
                  }),

            CHECK("Verify generated new session ticket message",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     result.test_bin_eq(
                        "New Session Ticket", ctx->pull_send_buffer(), vars.get_req_bin("Record_NewSessionTicket"));
                  }),

            CHECK("Receive Application Data",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.received_data(vars.get_req_bin("Record_Client_AppData"));
                     ctx->check_callback_invocations(result, "application data received", {"tls_record_received"});

                     const auto rcvd = ctx->pull_receive_buffer();
                     result.test_bin_eq("decrypted application traffic", rcvd, vars.get_req_bin("Client_AppData"));
                     result.test_u64_eq("sequence number", ctx->last_received_seq_no(), uint64_t(0));
                  }),

            CHECK("Send Application Data",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->send(vars.get_req_bin("Server_AppData"));

                     ctx->check_callback_invocations(result, "application data sent", {"tls_emit_data"});

                     result.test_bin_eq("correct server application data",
                                        ctx->pull_send_buffer(),
                                        vars.get_req_bin("Record_Server_AppData"));
                  }),

            CHECK("Receive Client's close_notify",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.received_data(vars.get_req_bin("Record_Client_CloseNotify"));

                     ctx->check_callback_invocations(
                        result, "client finished received", {"tls_alert", "tls_peer_closed_connection"});

                     result.test_is_true("connection is not yet closed", !ctx->server.is_closed());
                     result.test_is_true("connection is still active", ctx->server.is_active());
                     result.test_is_true("handshake is still finished", ctx->server.is_handshake_complete());
                  }),

            CHECK("Expect Server close_notify",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.close();

                     result.test_is_true("connection is now inactive", !ctx->server.is_active());
                     result.test_is_true("connection is now closed", ctx->server.is_closed());
                     result.test_is_true("handshake is still finished", ctx->server.is_handshake_complete());
                     result.test_bin_eq("Server's close notify",
                                        ctx->pull_send_buffer(),
                                        vars.get_req_bin("Record_Server_CloseNotify"));
                  }),
         };
      }

      std::vector<Test::Result> resumed_handshake_with_0_rtt(const VarMap& vars) override {
         auto rng = std::make_unique<Fixed_Output_RNG>();

         // 32 - for server hello random
         // 32 - for KeyShare (eph. x25519 key pair)
         add_entropy(*rng, vars.get_req_bin("Server_RNG_Pool"));

         std::unique_ptr<Server_Context> ctx;

         return {
            CHECK("Receive Client Hello",
                  [&](Test::Result& result) {
                     auto add_cookie_and_sort = [&](Botan::TLS::Extensions& exts,
                                                    Botan::TLS::Connection_Side side,
                                                    Botan::TLS::Handshake_Type type) {
                        if(type == Handshake_Type::EncryptedExtensions) {
                           exts.add(new EarlyDataIndication());  // NOLINT(*-owning-memory)
                        }
                        sort_rfc8448_extensions(exts, side, type);
                     };

                     ctx = std::make_unique<Server_Context>(
                        std::move(rng),
                        std::make_shared<RFC8448_Text_Policy>("rfc8448_1rtt"),
                        vars.get_req_u64("CurrentTimestamp"),
                        add_cookie_and_sort,
                        make_mock_signatures(vars),
                        false,
                        std::pair{Botan::TLS::Session(vars.get_req_bin("Client_SessionData")),
                                  Botan::TLS::Session_Ticket(vars.get_req_bin("SessionTicket"))});
                     result.test_is_true("server not closed", !ctx->server.is_closed());

                     ctx->server.received_data(vars.get_req_bin("Record_ClientHello_1"));

                     ctx->check_callback_invocations(result,
                                                     "client hello received",
                                                     {
                                                        "tls_emit_data",
                                                        "tls_current_timestamp",
                                                        "tls_generate_ephemeral_key",
                                                        "tls_ephemeral_key_agreement",
                                                        "tls_examine_extensions_client_hello",
                                                        "tls_modify_extensions_server_hello",
                                                        "tls_modify_extensions_encrypted_extensions",
                                                        "tls_inspect_handshake_msg_client_hello",
                                                        "tls_inspect_handshake_msg_server_hello",
                                                        "tls_inspect_handshake_msg_encrypted_extensions",
                                                        "tls_inspect_handshake_msg_finished",
                                                     });
                  }),

            CHECK("Verify generated messages in server's first flight",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     const auto& msgs = ctx->observed_handshake_messages();

                     result.test_bin_eq("Server Hello",
                                        msgs.at("server_hello")[0],
                                        strip_message_header(vars.get_opt_bin("Message_ServerHello")));
                     result.test_bin_eq("Encrypted Extensions",
                                        msgs.at("encrypted_extensions")[0],
                                        strip_message_header(vars.get_opt_bin("Message_EncryptedExtensions")));

                     result.test_bin_eq("Server's entire first flight",
                                        ctx->pull_send_buffer(),
                                        concat(vars.get_req_bin("Record_ServerHello"),
                                               vars.get_req_bin("Record_ServerHandshakeMessages")));

                     // Note: is_active() defines that we can send application data.
                     //       RFC 8446 Section 4.4.4 explicitly allows that for servers
                     //       that did not receive the client's Finished message, yet.
                     //       However, before receiving and validating this message,
                     //       the handshake is not yet finished.
                     result.test_is_true("Server can now send application data", ctx->server.is_active());
                     result.test_is_true("handshake is not yet complete", !ctx->server.is_handshake_complete());
                  }),

            // TODO: The rest of this test vector requires 0-RTT which is not
            //       yet implemented. For now we can only test the server's
            //       ability to acknowledge a session resumption via PSK.
         };
      }

      std::vector<Test::Result> hello_retry_request(const VarMap& vars) override {
         // Fallback RNG is required to for blinding in ECDH with P-256
         auto& fallback_rng = this->rng();
         auto rng = std::make_unique<Fixed_Output_RNG>(fallback_rng);

         // 32 - for server hello random
         // 32 - for KeyShare (eph. P-256 key pair)
         add_entropy(*rng, vars.get_req_bin("Server_RNG_Pool"));

         std::unique_ptr<Server_Context> ctx;

         return {
            CHECK("Receive Client Hello",
                  [&](Test::Result& result) {
                     auto add_cookie_and_sort = [&](Botan::TLS::Extensions& exts,
                                                    Botan::TLS::Connection_Side side,
                                                    Botan::TLS::Handshake_Type type) {
                        if(type == Handshake_Type::HelloRetryRequest) {
                           // This cookie needs to be mocked into the HRR since RFC 8448 contains it.
                           exts.add(
                              new Cookie(vars.get_opt_bin("HelloRetryRequest_Cookie")));  // NOLINT(*-owning-memory)
                        }
                        sort_rfc8448_extensions(exts, side, type);
                     };

                     ctx = std::make_unique<Server_Context>(std::move(rng),
                                                            std::make_shared<RFC8448_Text_Policy>("rfc8448_hrr_server"),
                                                            vars.get_req_u64("CurrentTimestamp"),
                                                            add_cookie_and_sort,
                                                            make_mock_signatures(vars));
                     result.test_is_true("server not closed", !ctx->server.is_closed());

                     ctx->server.received_data(vars.get_req_bin("Record_ClientHello_1"));

                     ctx->check_callback_invocations(result,
                                                     "client hello received",
                                                     {"tls_emit_data",
                                                      "tls_examine_extensions_client_hello",
                                                      "tls_modify_extensions_hello_retry_request",
                                                      "tls_inspect_handshake_msg_client_hello",
                                                      "tls_inspect_handshake_msg_hello_retry_request"});
                  }),

            CHECK("Verify generated Hello Retry Request message",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     result.test_bin_eq("Server's Hello Retry Request record",
                                        ctx->pull_send_buffer(),
                                        vars.get_req_bin("Record_HelloRetryRequest"));
                     result.test_is_true("TLS handshake not yet finished", !ctx->server.is_active());
                     result.test_is_true("handshake is not yet complete", !ctx->server.is_handshake_complete());
                  }),

            CHECK("Receive updated Client Hello message",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.received_data(vars.get_req_bin("Record_ClientHello_2"));

                     ctx->check_callback_invocations(result,
                                                     "updated client hello received",
                                                     {"tls_emit_data",
                                                      "tls_examine_extensions_client_hello",
                                                      "tls_modify_extensions_server_hello",
                                                      "tls_modify_extensions_encrypted_extensions",
                                                      "tls_modify_extensions_certificate",
                                                      "tls_sign_message",
                                                      "tls_generate_ephemeral_key",
                                                      "tls_ephemeral_key_agreement",
                                                      "tls_inspect_handshake_msg_client_hello",
                                                      "tls_inspect_handshake_msg_server_hello",
                                                      "tls_inspect_handshake_msg_encrypted_extensions",
                                                      "tls_inspect_handshake_msg_certificate",
                                                      "tls_inspect_handshake_msg_certificate_verify",
                                                      "tls_inspect_handshake_msg_finished"});
                  }),

            CHECK("Verify generated messages in server's second flight",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     const auto& msgs = ctx->observed_handshake_messages();

                     result.test_bin_eq("Server Hello",
                                        msgs.at("server_hello")[0],
                                        strip_message_header(vars.get_opt_bin("Message_ServerHello")));
                     result.test_bin_eq("Encrypted Extensions",
                                        msgs.at("encrypted_extensions")[0],
                                        strip_message_header(vars.get_opt_bin("Message_EncryptedExtensions")));
                     result.test_bin_eq("Certificate",
                                        msgs.at("certificate")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_Certificate")));
                     result.test_bin_eq("CertificateVerify",
                                        msgs.at("certificate_verify")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_CertificateVerify")));
                     result.test_bin_eq("Finished",
                                        msgs.at("finished")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_Finished")));

                     result.test_bin_eq("Server's entire second flight",
                                        ctx->pull_send_buffer(),
                                        concat(vars.get_req_bin("Record_ServerHello"),
                                               vars.get_req_bin("Record_ServerHandshakeMessages")));
                     result.test_is_true("Server could now send application data", ctx->server.is_active());
                     result.test_is_true("handshake is not yet complete",
                                         !ctx->server.is_handshake_complete());  // See RFC 8446 4.4.4
                  }),

            CHECK("Receive Client Finished",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.received_data(vars.get_req_bin("Record_ClientFinished"));

                     ctx->check_callback_invocations(result,
                                                     "client finished received",
                                                     {"tls_inspect_handshake_msg_finished",
                                                      "tls_current_timestamp",
                                                      "tls_session_established",
                                                      "tls_session_activated"});

                     result.test_is_true("TLS handshake finished", ctx->server.is_active());
                     result.test_is_true("handshake is complete", ctx->server.is_handshake_complete());
                  }),

            CHECK("Receive Client close_notify",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.received_data(vars.get_req_bin("Record_Client_CloseNotify"));

                     ctx->check_callback_invocations(
                        result, "client finished received", {"tls_alert", "tls_peer_closed_connection"});

                     result.test_is_true("connection is not yet closed", !ctx->server.is_closed());
                     result.test_is_true("connection is still active", ctx->server.is_active());
                     result.test_is_true("handshake is still complete", ctx->server.is_handshake_complete());
                  }),

            CHECK("Expect Server close_notify",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.close();

                     result.test_is_true("connection is now inactive", !ctx->server.is_active());
                     result.test_is_true("connection is now closed", ctx->server.is_closed());
                     result.test_is_true("handshake is still complete", ctx->server.is_handshake_complete());
                     result.test_bin_eq("Server's close notify",
                                        ctx->pull_send_buffer(),
                                        vars.get_req_bin("Record_Server_CloseNotify"));
                  }),

         };
      }

      std::vector<Test::Result> client_authentication(const VarMap& vars) override {
         auto rng = std::make_unique<Fixed_Output_RNG>("");

         // 32 - for server hello random
         // 32 - for KeyShare (eph. x25519 pair)
         add_entropy(*rng, vars.get_req_bin("Server_RNG_Pool"));

         std::unique_ptr<Server_Context> ctx;

         return {
            CHECK("Receive Client Hello",
                  [&](Test::Result& result) {
                     ctx = std::make_unique<Server_Context>(
                        std::move(rng),
                        std::make_shared<RFC8448_Text_Policy>("rfc8448_client_auth_server"),
                        vars.get_req_u64("CurrentTimestamp"),
                        sort_rfc8448_extensions,
                        make_mock_signatures(vars),
                        true /* use alternative certificate */);
                     result.test_is_true("server not closed", !ctx->server.is_closed());

                     ctx->server.received_data(vars.get_req_bin("Record_ClientHello_1"));

                     ctx->check_callback_invocations(result,
                                                     "client hello received",
                                                     {"tls_emit_data",
                                                      "tls_examine_extensions_client_hello",
                                                      "tls_modify_extensions_server_hello",
                                                      "tls_modify_extensions_encrypted_extensions",
                                                      "tls_modify_extensions_certificate_request",
                                                      "tls_modify_extensions_certificate",
                                                      "tls_sign_message",
                                                      "tls_generate_ephemeral_key",
                                                      "tls_ephemeral_key_agreement",
                                                      "tls_inspect_handshake_msg_client_hello",
                                                      "tls_inspect_handshake_msg_server_hello",
                                                      "tls_inspect_handshake_msg_encrypted_extensions",
                                                      "tls_inspect_handshake_msg_certificate_request",
                                                      "tls_inspect_handshake_msg_certificate",
                                                      "tls_inspect_handshake_msg_certificate_verify",
                                                      "tls_inspect_handshake_msg_finished"});
                  }),

            CHECK("Verify server's generated handshake messages",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     const auto& msgs = ctx->observed_handshake_messages();

                     result.test_bin_eq("Server Hello",
                                        msgs.at("server_hello")[0],
                                        strip_message_header(vars.get_opt_bin("Message_ServerHello")));
                     result.test_bin_eq("Encrypted Extensions",
                                        msgs.at("encrypted_extensions")[0],
                                        strip_message_header(vars.get_opt_bin("Message_EncryptedExtensions")));
                     result.test_bin_eq("Certificate Request",
                                        msgs.at("certificate_request")[0],
                                        strip_message_header(vars.get_opt_bin("Message_CertificateRequest")));
                     result.test_bin_eq("Certificate",
                                        msgs.at("certificate")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_Certificate")));
                     result.test_bin_eq("CertificateVerify",
                                        msgs.at("certificate_verify")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_CertificateVerify")));
                     result.test_bin_eq("Finished",
                                        msgs.at("finished")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_Finished")));

                     result.test_bin_eq("Server's entire first flight",
                                        ctx->pull_send_buffer(),
                                        concat(vars.get_req_bin("Record_ServerHello"),
                                               vars.get_req_bin("Record_ServerHandshakeMessages")));

                     result.test_is_true("Not yet aware of client's cert chain", ctx->server.peer_cert_chain().empty());
                     result.test_is_true("Server could now send application data", ctx->server.is_active());
                     result.test_is_true("handshake is not yet complete",
                                         !ctx->server.is_handshake_complete());  // See RFC 8446 4.4.4
                  }),

            CHECK("Receive Client's second flight",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     // This encrypted message contains the following messages:
                     // * client's Certificate message
                     // * client's Certificate_Verify message
                     // * client's Finished message
                     ctx->server.received_data(vars.get_req_bin("Record_ClientFinished"));

                     ctx->check_callback_invocations(result,
                                                     "client finished received",
                                                     {"tls_inspect_handshake_msg_certificate",
                                                      "tls_inspect_handshake_msg_certificate_verify",
                                                      "tls_inspect_handshake_msg_finished",
                                                      "tls_examine_extensions_certificate",
                                                      "tls_verify_cert_chain",
                                                      "tls_verify_message",
                                                      "tls_current_timestamp",
                                                      "tls_session_established",
                                                      "tls_session_activated"});

                     const auto cert_chain = ctx->server.peer_cert_chain();
                     result.test_is_true("Received client's cert chain",
                                         !cert_chain.empty() && cert_chain.front() == client_certificate());

                     result.test_is_true("TLS handshake finished", ctx->server.is_active());
                     result.test_is_true("handshake is complete", ctx->server.is_handshake_complete());
                  }),

            CHECK("Receive Client close_notify",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.received_data(vars.get_req_bin("Record_Client_CloseNotify"));

                     ctx->check_callback_invocations(
                        result, "client finished received", {"tls_alert", "tls_peer_closed_connection"});

                     result.test_is_true("connection is not yet closed", !ctx->server.is_closed());
                     result.test_is_true("connection is still active", ctx->server.is_active());
                     result.test_is_true("handshake is still complete", ctx->server.is_handshake_complete());
                  }),

            CHECK("Expect Server close_notify",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.close();

                     result.test_is_true("connection is now inactive", !ctx->server.is_active());
                     result.test_is_true("connection is now closed", ctx->server.is_closed());
                     result.test_is_true("handshake is still complete", ctx->server.is_handshake_complete());
                     result.test_bin_eq("Server's close notify",
                                        ctx->pull_send_buffer(),
                                        vars.get_req_bin("Record_Server_CloseNotify"));
                  }),

         };
      }

      std::vector<Test::Result> middlebox_compatibility(const VarMap& vars) override {
         auto rng = std::make_unique<Fixed_Output_RNG>("");

         // 32 - for server hello random
         // 32 - for KeyShare (eph. x25519 pair)
         add_entropy(*rng, vars.get_req_bin("Server_RNG_Pool"));

         std::unique_ptr<Server_Context> ctx;

         return {
            CHECK("Receive Client Hello",
                  [&](Test::Result& result) {
                     ctx =
                        std::make_unique<Server_Context>(std::move(rng),
                                                         std::make_shared<RFC8448_Text_Policy>("rfc8448_compat_server"),
                                                         vars.get_req_u64("CurrentTimestamp"),
                                                         sort_rfc8448_extensions,
                                                         make_mock_signatures(vars));
                     result.test_is_true("server not closed", !ctx->server.is_closed());

                     ctx->server.received_data(vars.get_req_bin("Record_ClientHello_1"));

                     ctx->check_callback_invocations(result,
                                                     "client hello received",
                                                     {"tls_emit_data",
                                                      "tls_examine_extensions_client_hello",
                                                      "tls_modify_extensions_server_hello",
                                                      "tls_modify_extensions_encrypted_extensions",
                                                      "tls_modify_extensions_certificate",
                                                      "tls_sign_message",
                                                      "tls_generate_ephemeral_key",
                                                      "tls_ephemeral_key_agreement",
                                                      "tls_inspect_handshake_msg_client_hello",
                                                      "tls_inspect_handshake_msg_server_hello",
                                                      "tls_inspect_handshake_msg_encrypted_extensions",
                                                      "tls_inspect_handshake_msg_certificate",
                                                      "tls_inspect_handshake_msg_certificate_verify",
                                                      "tls_inspect_handshake_msg_finished"});
                  }),

            CHECK("Verify server's generated handshake messages",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     const auto& msgs = ctx->observed_handshake_messages();

                     result.test_bin_eq("Server Hello",
                                        msgs.at("server_hello")[0],
                                        strip_message_header(vars.get_opt_bin("Message_ServerHello")));
                     result.test_bin_eq("Encrypted Extensions",
                                        msgs.at("encrypted_extensions")[0],
                                        strip_message_header(vars.get_opt_bin("Message_EncryptedExtensions")));
                     result.test_bin_eq("Certificate",
                                        msgs.at("certificate")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_Certificate")));
                     result.test_bin_eq("CertificateVerify",
                                        msgs.at("certificate_verify")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_CertificateVerify")));
                     result.test_bin_eq("Finished",
                                        msgs.at("finished")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_Finished")));

                     // Those records contain the required Change Cipher Spec message the server must produce for compatibility mode compliance
                     result.test_bin_eq("Server's entire first flight",
                                        ctx->pull_send_buffer(),
                                        concat(vars.get_req_bin("Record_ServerHello"),
                                               vars.get_req_bin("Record_ServerHandshakeMessages")));

                     result.test_is_true("Server could now send application data", ctx->server.is_active());
                     result.test_is_true("handshake is not yet complete",
                                         !ctx->server.is_handshake_complete());  // See RFC 8446 4.4.4
                  }),

            CHECK("Receive Client Finished",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.received_data(vars.get_req_bin("Record_ClientFinished"));

                     ctx->check_callback_invocations(result,
                                                     "client finished received",
                                                     {"tls_inspect_handshake_msg_finished",
                                                      "tls_current_timestamp",
                                                      "tls_session_established",
                                                      "tls_session_activated"});

                     result.test_is_true("TLS handshake fully finished", ctx->server.is_active());
                     result.test_is_true("handshake is complete", ctx->server.is_handshake_complete());
                  }),

            CHECK("Receive Client close_notify",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.received_data(vars.get_req_bin("Record_Client_CloseNotify"));

                     ctx->check_callback_invocations(
                        result, "client finished received", {"tls_alert", "tls_peer_closed_connection"});

                     result.test_is_true("connection is not yet closed", !ctx->server.is_closed());
                     result.test_is_true("connection is still active", ctx->server.is_active());
                     result.test_is_true("handshake is still complete", ctx->server.is_handshake_complete());
                  }),

            CHECK("Expect Server close_notify",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.close();

                     result.test_is_true("connection is now inactive", !ctx->server.is_active());
                     result.test_is_true("connection is now closed", ctx->server.is_closed());
                     result.test_is_true("handshake is still complete", ctx->server.is_handshake_complete());
                     result.test_bin_eq("Server's close notify",
                                        ctx->pull_send_buffer(),
                                        vars.get_req_bin("Record_Server_CloseNotify"));
                  }),

         };
      }

      std::vector<Test::Result> externally_provided_psk_with_ephemeral_key(const VarMap& vars) override {
         auto rng = std::make_unique<Fixed_Output_RNG>("");

         // 32 - for server hello random
         // 32 - for KeyShare (eph. x25519 key pair)
         add_entropy(*rng, vars.get_req_bin("Server_RNG_Pool"));

         std::unique_ptr<Server_Context> ctx;

         return {
            CHECK("Send Client Hello",
                  [&](Test::Result& result) {
                     auto sort_our_extensions = [&](Botan::TLS::Extensions& exts,
                                                    Botan::TLS::Connection_Side /* side */,
                                                    Botan::TLS::Handshake_Type type) {
                        // This is the order of extensions when we first introduced the PSK
                        // implementation and generated the transcript. To stay compatible
                        // with the now hard-coded transcript, we pin the extension order.
                        if(type == Botan::TLS::Handshake_Type::EncryptedExtensions) {
                           exts.reorder({
                              Botan::TLS::Extension_Code::SupportedGroups,
                              Botan::TLS::Extension_Code::RecordSizeLimit,
                              Botan::TLS::Extension_Code::ServerNameIndication,
                           });
                        } else if(type == Botan::TLS::Handshake_Type::ServerHello) {
                           exts.reorder({
                              Botan::TLS::Extension_Code::SupportedVersions,
                              Botan::TLS::Extension_Code::KeyShare,
                              Botan::TLS::Extension_Code::PresharedKey,
                           });
                        }
                     };

                     ctx = std::make_unique<Server_Context>(
                        std::move(rng),
                        std::make_shared<RFC8448_Text_Policy>("rfc8448_psk_dhe", false /* no rfc8448 */),
                        vars.get_req_u64("CurrentTimestamp"),
                        sort_our_extensions,
                        make_mock_signatures(vars),
                        false,
                        std::nullopt,
                        ExternalPSK(vars.get_req_str("PskIdentity"),
                                    vars.get_req_str("PskPRF"),
                                    lock(vars.get_req_bin("PskSecret"))));
                     result.test_is_true("server not closed", !ctx->server.is_closed());

                     ctx->server.received_data(vars.get_req_bin("Record_ClientHello_1"));

                     ctx->check_callback_invocations(result,
                                                     "client hello received",
                                                     {"tls_emit_data",
                                                      "tls_examine_extensions_client_hello",
                                                      "tls_modify_extensions_server_hello",
                                                      "tls_modify_extensions_encrypted_extensions",
                                                      "tls_generate_ephemeral_key",
                                                      "tls_ephemeral_key_agreement",
                                                      "tls_inspect_handshake_msg_client_hello",
                                                      "tls_inspect_handshake_msg_server_hello",
                                                      "tls_inspect_handshake_msg_encrypted_extensions",
                                                      "tls_inspect_handshake_msg_finished"});
                  }),

            CHECK("Verify generated messages in server's first flight",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     const auto& msgs = ctx->observed_handshake_messages();

                     result.test_bin_eq("Server Hello",
                                        msgs.at("server_hello")[0],
                                        strip_message_header(vars.get_opt_bin("Message_ServerHello")));
                     result.test_bin_eq("Encrypted Extensions",
                                        msgs.at("encrypted_extensions")[0],
                                        strip_message_header(vars.get_opt_bin("Message_EncryptedExtensions")));
                     result.test_bin_eq("Server Finished",
                                        msgs.at("finished")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_Finished")));

                     result.test_bin_eq("Server's entire first flight",
                                        ctx->pull_send_buffer(),
                                        concat(vars.get_req_bin("Record_ServerHello"),
                                               vars.get_req_bin("Record_ServerHandshakeMessages")));

                     result.test_is_true("Server can now send application data", ctx->server.is_active());
                     result.test_is_true("handshake is not yet complete",
                                         !ctx->server.is_handshake_complete());  // See RFC 8446 4.4.4
                  }),

            CHECK("Send Client Finished",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.received_data(vars.get_req_bin("Record_ClientFinished"));
                     result.require("PSK negotiated",
                                    ctx->psk_identity_negotiated() == vars.get_req_str("PskIdentity"));

                     ctx->check_callback_invocations(result,
                                                     "client finished received",
                                                     {"tls_inspect_handshake_msg_finished",
                                                      "tls_current_timestamp",
                                                      "tls_session_established",
                                                      "tls_session_activated"});
                  }),

            CHECK("Exchange Application Data",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.received_data(vars.get_req_bin("Record_Client_AppData"));
                     ctx->check_callback_invocations(result, "application data received", {"tls_record_received"});

                     const auto rcvd = ctx->pull_receive_buffer();
                     result.test_bin_eq("decrypted application traffic", rcvd, vars.get_req_bin("Client_AppData"));
                     result.test_u64_eq("sequence number", ctx->last_received_seq_no(), uint64_t(0));

                     ctx->send(vars.get_req_bin("Server_AppData"));
                     ctx->check_callback_invocations(result, "application data sent", {"tls_emit_data"});
                     result.test_bin_eq("correct server application data",
                                        ctx->pull_send_buffer(),
                                        vars.get_req_bin("Record_Server_AppData"));
                  }),

            CHECK("Terminate Connection",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.received_data(vars.get_req_bin("Record_Client_CloseNotify"));

                     ctx->check_callback_invocations(
                        result, "client finished received", {"tls_alert", "tls_peer_closed_connection"});

                     result.test_is_true("connection is not yet closed", !ctx->server.is_closed());
                     result.test_is_true("connection is still active", ctx->server.is_active());
                     result.test_is_true("handshake is still complete", ctx->server.is_handshake_complete());

                     ctx->server.close();

                     result.test_is_true("connection is now inactive", !ctx->server.is_active());
                     result.test_is_true("connection is now closed", ctx->server.is_closed());
                     result.test_is_true("handshake is still complete", ctx->server.is_handshake_complete());
                     result.test_bin_eq("Server's close notify",
                                        ctx->pull_send_buffer(),
                                        vars.get_req_bin("Record_Server_CloseNotify"));
                  }),
         };
      }

      std::vector<Test::Result> raw_public_key_with_client_authentication(const VarMap& vars) override {
         auto rng = std::make_unique<Fixed_Output_RNG>("");

         // 32 - for server hello random
         // 32 - for KeyShare (eph. x25519 key pair)
         add_entropy(*rng, vars.get_req_bin("Server_RNG_Pool"));

         auto sort_our_extensions =
            [&](Botan::TLS::Extensions& exts, Botan::TLS::Connection_Side /* side */, Botan::TLS::Handshake_Type type) {
               // This is the order of extensions when we first introduced the raw
               // public key authentication implementation and generated the transcript.
               // To stay compatible with the now hard-coded transcript, we pin the
               // extension order.
               if(type == Botan::TLS::Handshake_Type::EncryptedExtensions) {
                  exts.reorder({
                     Botan::TLS::Extension_Code::ClientCertificateType,
                     Botan::TLS::Extension_Code::ServerCertificateType,
                     Botan::TLS::Extension_Code::SupportedGroups,
                     Botan::TLS::Extension_Code::RecordSizeLimit,
                     Botan::TLS::Extension_Code::ServerNameIndication,
                  });
               } else if(type == Botan::TLS::Handshake_Type::ServerHello) {
                  exts.reorder({
                     Botan::TLS::Extension_Code::KeyShare,
                     Botan::TLS::Extension_Code::SupportedVersions,
                  });
               }
            };

         std::unique_ptr<Server_Context> ctx;

         return {
            CHECK("Receive Client Hello",
                  [&](Test::Result& result) {
                     ctx = std::make_unique<Server_Context>(std::move(rng),
                                                            std::make_shared<RFC8448_Text_Policy>("rfc8448_rawpubkey"),
                                                            vars.get_req_u64("CurrentTimestamp"),
                                                            sort_our_extensions,
                                                            make_mock_signatures(vars));
                     result.test_is_true("server not closed", !ctx->server.is_closed());

                     ctx->server.received_data(vars.get_req_bin("Record_ClientHello_1"));

                     ctx->check_callback_invocations(result,
                                                     "client hello received",
                                                     {"tls_emit_data",
                                                      "tls_examine_extensions_client_hello",
                                                      "tls_modify_extensions_server_hello",
                                                      "tls_modify_extensions_encrypted_extensions",
                                                      "tls_modify_extensions_certificate_request",
                                                      "tls_modify_extensions_certificate",
                                                      "tls_sign_message",
                                                      "tls_generate_ephemeral_key",
                                                      "tls_ephemeral_key_agreement",
                                                      "tls_inspect_handshake_msg_client_hello",
                                                      "tls_inspect_handshake_msg_server_hello",
                                                      "tls_inspect_handshake_msg_encrypted_extensions",
                                                      "tls_inspect_handshake_msg_certificate_request",
                                                      "tls_inspect_handshake_msg_certificate",
                                                      "tls_inspect_handshake_msg_certificate_verify",
                                                      "tls_inspect_handshake_msg_finished"});
                  }),

            CHECK("Verify server's generated handshake messages",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     const auto& msgs = ctx->observed_handshake_messages();

                     result.test_bin_eq("Server Hello",
                                        msgs.at("server_hello")[0],
                                        strip_message_header(vars.get_opt_bin("Message_ServerHello")));
                     result.test_bin_eq("Encrypted Extensions",
                                        msgs.at("encrypted_extensions")[0],
                                        strip_message_header(vars.get_opt_bin("Message_EncryptedExtensions")));
                     result.test_bin_eq("Certificate Request",
                                        msgs.at("certificate_request")[0],
                                        strip_message_header(vars.get_opt_bin("Message_CertificateRequest")));
                     result.test_bin_eq("Certificate",
                                        msgs.at("certificate")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_Certificate")));
                     result.test_bin_eq("CertificateVerify",
                                        msgs.at("certificate_verify")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_CertificateVerify")));
                     result.test_bin_eq("Finished",
                                        msgs.at("finished")[0],
                                        strip_message_header(vars.get_opt_bin("Message_Server_Finished")));

                     result.test_bin_eq("Server's entire first flight",
                                        ctx->pull_send_buffer(),
                                        concat(vars.get_req_bin("Record_ServerHello"),
                                               vars.get_req_bin("Record_ServerHandshakeMessages")));

                     result.test_is_true("Not yet aware of client's cert chain", ctx->server.peer_cert_chain().empty());
                     result.test_is_true("Server could now send application data", ctx->server.is_active());
                     result.test_is_true("handshake is not yet complete",
                                         !ctx->server.is_handshake_complete());  // See RFC 8446 4.4.4
                  }),

            CHECK("Receive Client's second flight",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     // This encrypted message contains the following messages:
                     // * client's Certificate message
                     // * client's Certificate_Verify message
                     // * client's Finished message
                     ctx->server.received_data(vars.get_req_bin("Record_ClientFinished"));

                     ctx->check_callback_invocations(result,
                                                     "client finished received",
                                                     {"tls_inspect_handshake_msg_certificate",
                                                      "tls_inspect_handshake_msg_certificate_verify",
                                                      "tls_inspect_handshake_msg_finished",
                                                      "tls_examine_extensions_certificate",
                                                      "tls_verify_raw_public_key",
                                                      "tls_verify_message",
                                                      "tls_current_timestamp",
                                                      "tls_session_established",
                                                      "tls_session_activated"});

                     const auto raw_pk = ctx->server.peer_raw_public_key();
                     result.test_is_true(
                        "Received client's raw public key",
                        raw_pk && raw_pk->fingerprint_public() == client_raw_public_key_pair()->fingerprint_public());

                     result.test_is_true("TLS handshake finished", ctx->server.is_active());
                     result.test_is_true("handshake is complete", ctx->server.is_handshake_complete());
                  }),

            CHECK("Receive Client close_notify",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.received_data(vars.get_req_bin("Record_Client_CloseNotify"));

                     ctx->check_callback_invocations(
                        result, "client finished received", {"tls_alert", "tls_peer_closed_connection"});

                     result.test_is_true("connection is not yet closed", !ctx->server.is_closed());
                     result.test_is_true("connection is still active", ctx->server.is_active());
                     result.test_is_true("handshake is still complete", ctx->server.is_handshake_complete());
                  }),

            CHECK("Expect Server close_notify",
                  [&](Test::Result& result) {
                     result.require("ctx is available", ctx != nullptr);
                     ctx->server.close();

                     result.test_is_true("connection is now inactive", !ctx->server.is_active());
                     result.test_is_true("connection is now closed", ctx->server.is_closed());
                     result.test_is_true("handshake is still complete", ctx->server.is_handshake_complete());
                     result.test_bin_eq("Server's close notify",
                                        ctx->pull_send_buffer(),
                                        vars.get_req_bin("Record_Server_CloseNotify"));
                  }),
         };
      }
};

BOTAN_REGISTER_TEST("tls", "tls_rfc8448_client", Test_TLS_RFC8448_Client);
BOTAN_REGISTER_TEST("tls", "tls_rfc8448_server", Test_TLS_RFC8448_Server);

#endif

}  // namespace

}  // namespace Botan_Tests
