//
//
// Copyright 2015 gRPC authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//

#ifndef GRPC_SRC_CORE_TSI_TRANSPORT_SECURITY_H
#define GRPC_SRC_CORE_TSI_TRANSPORT_SECURITY_H

#include <grpc/support/port_platform.h>
#include <stdbool.h>

#include "src/core/lib/debug/trace.h"
#include "src/core/tsi/transport_security_interface.h"

// Base for tsi_frame_protector implementations.
// See transport_security_interface.h for documentation.
// All methods must be implemented.
// Implementations must provide the following thread-safety guarantees:
// - protect and unprotect can be called concurrently,
// - protect_flush and unprotect can be called concurrently.
struct tsi_frame_protector_vtable {
  tsi_result (*protect)(tsi_frame_protector* self,
                        const unsigned char* unprotected_bytes,
                        size_t* unprotected_bytes_size,
                        unsigned char* protected_output_frames,
                        size_t* protected_output_frames_size);
  tsi_result (*protect_flush)(tsi_frame_protector* self,
                              unsigned char* protected_output_frames,
                              size_t* protected_output_frames_size,
                              size_t* still_pending_size);
  tsi_result (*unprotect)(tsi_frame_protector* self,
                          const unsigned char* protected_frames_bytes,
                          size_t* protected_frames_bytes_size,
                          unsigned char* unprotected_bytes,
                          size_t* unprotected_bytes_size);
  void (*destroy)(tsi_frame_protector* self);
};
struct tsi_frame_protector {
  const tsi_frame_protector_vtable* vtable;
};

// Base for tsi_handshaker implementations.
// See transport_security_interface.h for documentation.
struct tsi_handshaker_vtable {
  // Methods for supporting the old synchronous API.
  // These can be null if the TSI impl supports only the new
  // async-capable API.
  tsi_result (*get_bytes_to_send_to_peer)(tsi_handshaker* self,
                                          unsigned char* bytes,
                                          size_t* bytes_size);
  tsi_result (*process_bytes_from_peer)(tsi_handshaker* self,
                                        const unsigned char* bytes,
                                        size_t* bytes_size);
  tsi_result (*get_result)(tsi_handshaker* self);
  tsi_result (*extract_peer)(tsi_handshaker* self, tsi_peer* peer);
  tsi_result (*create_frame_protector)(tsi_handshaker* self,
                                       size_t* max_protected_frame_size,
                                       tsi_frame_protector** protector);
  // Must be implemented by all TSI impls.
  void (*destroy)(tsi_handshaker* self);
  // Methods for supporting the new async-capable API.
  // These can be null if the TSI impl supports only the old sync API.
  tsi_result (*next)(tsi_handshaker* self, const unsigned char* received_bytes,
                     size_t received_bytes_size,
                     const unsigned char** bytes_to_send,
                     size_t* bytes_to_send_size,
                     tsi_handshaker_result** handshaker_result,
                     tsi_handshaker_on_next_done_cb cb, void* user_data,
                     std::string* error);
  void (*shutdown)(tsi_handshaker* self);
};
struct tsi_handshaker {
  const tsi_handshaker_vtable* vtable;
  bool frame_protector_created;
  bool handshaker_result_created;
  bool handshake_shutdown;
};

// Base for tsi_handshaker_result implementations.
// See transport_security_interface.h for documentation.
// The exec_ctx parameter in create_zero_copy_grpc_protector is supposed to be
// of type grpc_exec_ctx*, but we're using void* instead to avoid making the TSI
// API depend on grpc. The create_zero_copy_grpc_protector() method is only used
// in grpc, where we do need the exec_ctx passed through, but the API still
// needs to compile in other applications, where grpc_exec_ctx is not defined.
// All methods must be non-null, except where noted below.
//
struct tsi_handshaker_result_vtable {
  tsi_result (*extract_peer)(const tsi_handshaker_result* self, tsi_peer* peer);
  tsi_result (*get_frame_protector_type)(
      const tsi_handshaker_result* self,
      tsi_frame_protector_type* frame_protector_type);
  // May be null if get_frame_protector_type() returns
  // TSI_FRAME_PROTECTOR_NORMAL or TSI_FRAME_PROTECTOR_NONE.
  tsi_result (*create_zero_copy_grpc_protector)(
      const tsi_handshaker_result* self,
      size_t* max_output_protected_frame_size,
      tsi_zero_copy_grpc_protector** protector);
  // May be null if get_frame_protector_type() returns
  // TSI_FRAME_PROTECTOR_ZERO_COPY or TSI_FRAME_PROTECTOR_NONE.
  tsi_result (*create_frame_protector)(const tsi_handshaker_result* self,
                                       size_t* max_output_protected_frame_size,
                                       tsi_frame_protector** protector);
  tsi_result (*get_unused_bytes)(const tsi_handshaker_result* self,
                                 const unsigned char** bytes,
                                 size_t* bytes_size);
  void (*destroy)(tsi_handshaker_result* self);
};
struct tsi_handshaker_result {
  const tsi_handshaker_result_vtable* vtable;
};

// Peer and property construction/destruction functions.
tsi_result tsi_construct_peer(size_t property_count, tsi_peer* peer);
tsi_peer_property tsi_init_peer_property(void);
void tsi_peer_property_destruct(tsi_peer_property* property);
tsi_result tsi_construct_string_peer_property(const char* name,
                                              const char* value,
                                              size_t value_length,
                                              tsi_peer_property* property);
tsi_result tsi_construct_allocated_string_peer_property(
    const char* name, size_t value_length, tsi_peer_property* property);
tsi_result tsi_construct_string_peer_property_from_cstring(
    const char* name, const char* value, tsi_peer_property* property);
const tsi_peer_property* tsi_peer_get_property_by_name(const tsi_peer* peer,
                                                       const char* name);
// Utils.
char* tsi_strdup(const char* src);  // Sadly, no strdup in C89.

#endif  // GRPC_SRC_CORE_TSI_TRANSPORT_SECURITY_H
