/*
 *
 * 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_CORE_TSI_TRANSPORT_SECURITY_H
#define GRPC_CORE_TSI_TRANSPORT_SECURITY_H

#include <stdbool.h>

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

#ifdef __cplusplus
extern "C" {
#endif

extern grpc_core::Tracer tsi_tracing_enabled;

/* Base for tsi_frame_protector implementations.
   See transport_security_interface.h for documentation. */
typedef struct {
  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);
} tsi_frame_protector_vtable;

struct tsi_frame_protector {
  const tsi_frame_protector_vtable *vtable;
};

/* Base for tsi_handshaker implementations.
   See transport_security_interface.h for documentation. */
typedef struct {
  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);
  void (*destroy)(tsi_handshaker *self);
  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);
} tsi_handshaker_vtable;

struct tsi_handshaker {
  const tsi_handshaker_vtable *vtable;
  bool frame_protector_created;
  bool handshaker_result_created;
};

/* 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.
*/
typedef struct {
  tsi_result (*extract_peer)(const tsi_handshaker_result *self, tsi_peer *peer);
  tsi_result (*create_zero_copy_grpc_protector)(
      void *exec_ctx, const tsi_handshaker_result *self,
      size_t *max_output_protected_frame_size,
      tsi_zero_copy_grpc_protector **protector);
  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);
} tsi_handshaker_result_vtable;

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);

/* Utils. */
char *tsi_strdup(const char *src); /* Sadly, no strdup in C89. */

#ifdef __cplusplus
}
#endif

#endif /* GRPC_CORE_TSI_TRANSPORT_SECURITY_H */