/*
 * Copyright (c) 2018 Intel and/or its affiliates.
 * 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.
 */
#include <vnet/vnet.h>
#include <vnet/api_errno.h>
#include <vlib/node_funcs.h>
#include <openssl/engine.h>
#include <tlsopenssl/tls_openssl.h>

#define SSL_ASYNC_INFLIGHT    1
#define SSL_ASYNC_READY       2
#define SSL_ASYNC_REENTER     3
#define MAX_VECTOR_ASYNC    256

typedef struct openssl_tls_callback_arg_
{
  int thread_index;
  int event_index;
} openssl_tls_callback_arg_t;

typedef struct openssl_event_
{
  u32 ctx_index;
  int session_index;
  u8 status;

  openssl_resume_handler *handler;
  openssl_tls_callback_arg_t cb_args;
#define thread_idx cb_args.thread_index
#define event_idx cb_args.event_index
  int next;
} openssl_evt_t;

typedef struct openssl_async_queue_
{
  int evt_run_head;
  int evt_run_tail;
} openssl_async_queue_t;

typedef struct openssl_async_
{
  openssl_evt_t ***evt_pool;
  openssl_async_queue_t *queue;
  void (*polling) (void);
  u8 start_polling;
  ENGINE *engine;

} openssl_async_t;

void qat_polling ();
void qat_pre_init ();
void qat_polling_config ();
void dasync_polling ();

struct engine_polling
{
  char *engine;
  void (*polling) (void);
  void (*pre_init) (void);
  void (*thread_init) (void *);
};

void qat_init_thread (void *arg);

struct engine_polling engine_list[] = {
  {"qat", qat_polling, qat_pre_init, qat_init_thread},
  {"dasync", dasync_polling, NULL, NULL}
};

openssl_async_t openssl_async_main;
static vlib_node_registration_t tls_async_process_node;

/* to avoid build warning */
void session_send_rpc_evt_to_thread (u32 thread_index, void *fp,
				     void *rpc_args);

void
evt_pool_init (vlib_main_t * vm)
{
  vlib_thread_main_t *vtm = vlib_get_thread_main ();
  openssl_async_t *om = &openssl_async_main;
  int i, num_threads;

  num_threads = 1 /* main thread */  + vtm->n_threads;

  TLS_DBG (2, "Totally there is %d thread\n", num_threads);

  vec_validate (om->evt_pool, num_threads - 1);
  vec_validate (om->queue, num_threads - 1);

  om->start_polling = 0;
  om->engine = 0;

  for (i = 0; i < num_threads; i++)
    {
      om->queue[i].evt_run_head = -1;
      om->queue[i].evt_run_tail = -1;
    }
  om->polling = NULL;

  return;
}

int
openssl_engine_register (char *engine_name, char *algorithm, int async)
{
  int i, registered = -1;
  openssl_async_t *om = &openssl_async_main;
  void (*p) (void);
  ENGINE *engine;

  for (i = 0; i < ARRAY_LEN (engine_list); i++)
    {
      if (!strcmp (engine_list[i].engine, engine_name))
	{
	  om->polling = engine_list[i].polling;
	  registered = i;
	}
    }
  if (registered < 0)
    {
      clib_error ("engine %s is not regisered in VPP", engine_name);
      return -1;
    }

  ENGINE_load_builtin_engines ();
  ENGINE_load_dynamic ();
  engine = ENGINE_by_id (engine_name);

  if (engine == NULL)
    {
      clib_warning ("Failed to find engine ENGINE_by_id %s", engine_name);
      return -1;
    }

  om->engine = engine;
  /* call pre-init */
  p = engine_list[registered].pre_init;
  if (p)
    (*p) ();

  if (algorithm)
    {
      if (!ENGINE_set_default_string (engine, algorithm))
	{
	  clib_warning ("Failed to set engine %s algorithm %s\n",
			engine_name, algorithm);
	  return -1;
	}
    }
  else
    {
      if (!ENGINE_set_default (engine, ENGINE_METHOD_ALL))
	{
	  clib_warning ("Failed to set engine %s to all algorithm",
			engine_name);
	  return -1;
	}
    }

  if (async)
    {
      openssl_async_node_enable_disable (1);
    }

  for (i = 0; i < vlib_num_workers (); i++)
    {
      if (engine_list[registered].thread_init)
	session_send_rpc_evt_to_thread (i + 1,
					engine_list[registered].thread_init,
					uword_to_pointer (i, void *));
    }

  om->start_polling = 1;

  return 0;

}

static openssl_evt_t *
openssl_evt_get (u32 evt_index)
{
  openssl_evt_t **evt;
  evt =
    pool_elt_at_index (openssl_async_main.evt_pool[vlib_get_thread_index ()],
		       evt_index);
  return *evt;
}

static openssl_evt_t *
openssl_evt_get_w_thread (int evt_index, u8 thread_index)
{
  openssl_evt_t **evt;

  evt =
    pool_elt_at_index (openssl_async_main.evt_pool[thread_index], evt_index);
  return *evt;
}

int
openssl_evt_free (int event_index, u8 thread_index)
{
  openssl_async_t *om = &openssl_async_main;

  /*pool operation */
  pool_put_index (om->evt_pool[thread_index], event_index);

  return 1;
}

static u32
openssl_evt_alloc (void)
{
  u8 thread_index = vlib_get_thread_index ();
  openssl_async_t *tm = &openssl_async_main;
  openssl_evt_t **evt;

  pool_get (tm->evt_pool[thread_index], evt);
  if (!(*evt))
    *evt = clib_mem_alloc (sizeof (openssl_evt_t));

  clib_memset (*evt, 0, sizeof (openssl_evt_t));
  (*evt)->event_idx = evt - tm->evt_pool[thread_index];
  return ((*evt)->event_idx);
}


/* In most cases, tls_async_openssl_callback is called by HW to make event active
 * When EAGAIN received, VPP will call this callback to retry
 */
int
tls_async_openssl_callback (SSL * s, void *cb_arg)
{
  openssl_evt_t *event, *event_tail;
  openssl_async_t *om = &openssl_async_main;
  openssl_tls_callback_arg_t *args = (openssl_tls_callback_arg_t *) cb_arg;
  int thread_index = args->thread_index;
  int event_index = args->event_index;
  int *evt_run_tail = &om->queue[thread_index].evt_run_tail;
  int *evt_run_head = &om->queue[thread_index].evt_run_head;

  TLS_DBG (2, "Set event %d to run\n", event_index);
  event = openssl_evt_get_w_thread (event_index, thread_index);

  /* Happend when a recursive case, especially in SW simulation */
  if (PREDICT_FALSE (event->status == SSL_ASYNC_READY))
    {
      event->status = SSL_ASYNC_REENTER;
      return 0;
    }
  event->status = SSL_ASYNC_READY;
  event->next = -1;

  if (*evt_run_tail >= 0)
    {
      event_tail = openssl_evt_get_w_thread (*evt_run_tail, thread_index);
      event_tail->next = event_index;
    }
  *evt_run_tail = event_index;
  if (*evt_run_head < 0)
    {
      *evt_run_head = event_index;
    }

  return 1;
}

int
vpp_tls_async_init_event (tls_ctx_t * ctx,
			  openssl_resume_handler * handler,
			  session_t * session)
{
  u32 eidx;
  openssl_evt_t *event;
  openssl_ctx_t *oc = (openssl_ctx_t *) ctx;
  u32 thread_id = ctx->c_thread_index;

  eidx = openssl_evt_alloc ();
  event = openssl_evt_get (eidx);
  event->ctx_index = oc->openssl_ctx_index;
  event->event_idx = eidx;
  event->thread_idx = thread_id;
  event->handler = handler;
  event->session_index = session->session_index;
  event->status = 0;
  ctx->evt_index = eidx;
#ifdef HAVE_OPENSSL_ASYNC
  SSL_set_async_callback_arg (oc->ssl, &event->cb_args);
#endif

  return 1;
}

int
vpp_openssl_is_inflight (tls_ctx_t * ctx)
{
  u32 eidx;
  openssl_evt_t *event;
  eidx = ctx->evt_index;
  event = openssl_evt_get (eidx);

  if (event->status == SSL_ASYNC_INFLIGHT)
    return 1;
  return 0;
}

int
vpp_tls_async_update_event (tls_ctx_t * ctx, int eagain)
{
  u32 eidx;
  openssl_evt_t *event;

  eidx = ctx->evt_index;
  event = openssl_evt_get (eidx);
  event->status = SSL_ASYNC_INFLIGHT;
  if (eagain)
    return tls_async_openssl_callback (0, &event->cb_args);

  return 1;
}

void
event_handler (void *tls_async)
{
  openssl_resume_handler *handler;
  openssl_evt_t *event;
  session_t *session;
  int thread_index;
  tls_ctx_t *ctx;

  event = (openssl_evt_t *) tls_async;
  thread_index = event->thread_idx;
  ctx = openssl_ctx_get_w_thread (event->ctx_index, thread_index);
  handler = event->handler;
  session = session_get (event->session_index, thread_index);

  if (handler)
    {
      (*handler) (ctx, session);
    }

  return;
}

 /* engine specific code to polling the response ring */
void
dasync_polling ()
{
/* dasync is a fake async device, and could not be polled.
 * We have added code in the dasync engine to triggered the callback already,
 * so nothing can be done here
 */
}

void
qat_pre_init ()
{
  openssl_async_t *om = &openssl_async_main;

  ENGINE_ctrl_cmd (om->engine, "ENABLE_EXTERNAL_POLLING", 0, NULL, NULL, 0);
}

/* Below code is spefic to QAT engine, and other vendors can refer to this code to enable a new engine */
void
qat_init_thread (void *arg)
{
  openssl_async_t *om = &openssl_async_main;
  int thread_index = pointer_to_uword (arg);

  ENGINE_ctrl_cmd (om->engine, "SET_INSTANCE_FOR_THREAD", thread_index,
		   NULL, NULL, 0);

  TLS_DBG (2, "set thread %d and instance %d mapping\n", thread_index,
	   thread_index);

}

void
qat_polling ()
{
  openssl_async_t *om = &openssl_async_main;
  int poll_status = 0;

  if (om->start_polling)
    {
      ENGINE_ctrl_cmd (om->engine, "POLL", 0, &poll_status, NULL, 0);
    }
}

void
openssl_async_polling ()
{
  openssl_async_t *om = &openssl_async_main;
  if (om->polling)
    {
      (*om->polling) ();
    }
}

void
openssl_async_node_enable_disable (u8 is_en)
{
  u8 state = is_en ? VLIB_NODE_STATE_POLLING : VLIB_NODE_STATE_DISABLED;
  vlib_thread_main_t *vtm = vlib_get_thread_main ();
  u8 have_workers = vtm->n_threads != 0;

  foreach_vlib_main ()
    {
      if (have_workers && this_vlib_main->thread_index)
	{
	  vlib_node_set_state (this_vlib_main, tls_async_process_node.index,
			       state);
	}
    }
}

int
tls_async_do_job (int eidx, u32 thread_index)
{
  tls_ctx_t *ctx;
  openssl_evt_t *event;

  /* do the real job */
  event = openssl_evt_get_w_thread (eidx, thread_index);
  ctx = openssl_ctx_get_w_thread (event->ctx_index, thread_index);

  if (ctx)
    {
      ctx->flags |= TLS_CONN_F_RESUME;
      session_send_rpc_evt_to_thread (thread_index, event_handler, event);
    }
  return 1;
}

int
tls_resume_from_crypto (int thread_index)
{
  int i;

  openssl_async_t *om = &openssl_async_main;
  openssl_evt_t *event;
  int *evt_run_head = &om->queue[thread_index].evt_run_head;
  int *evt_run_tail = &om->queue[thread_index].evt_run_tail;

  if (*evt_run_head < 0)
    return 0;

  for (i = 0; i < MAX_VECTOR_ASYNC; i++)
    {
      if (*evt_run_head >= 0)
	{
	  event = openssl_evt_get_w_thread (*evt_run_head, thread_index);
	  tls_async_do_job (*evt_run_head, thread_index);
	  if (PREDICT_FALSE (event->status == SSL_ASYNC_REENTER))
	    {
	      /* recusive event triggered */
	      event->status = SSL_ASYNC_READY;
	      continue;
	    }

	  event->status = 0;
	  *evt_run_head = event->next;

	  if (event->next < 0)
	    {
	      *evt_run_tail = -1;
	      break;
	    }
	}
    }

  return 0;

}

static clib_error_t *
tls_async_init (vlib_main_t * vm)
{
  evt_pool_init (vm);
  return 0;
}

static uword
tls_async_process (vlib_main_t * vm, vlib_node_runtime_t * rt,
		   vlib_frame_t * f)
{
  u8 thread_index;
  openssl_async_t *om = &openssl_async_main;

  thread_index = vlib_get_thread_index ();
  if (pool_elts (om->evt_pool[thread_index]) > 0)
    {
      openssl_async_polling ();
      tls_resume_from_crypto (thread_index);
    }

  return 0;
}

VLIB_INIT_FUNCTION (tls_async_init);

VLIB_REGISTER_NODE (tls_async_process_node,static) = {
    .function = tls_async_process,
    .type = VLIB_NODE_TYPE_INPUT,
    .name = "tls-async-process",
    .state = VLIB_NODE_STATE_DISABLED,
};


/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */