/*
* Copyright (c) 2015-2017 Cisco 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 <vlibmemory/api.h>
#include <vnet/session/application.h>
#include <vnet/session/application_interface.h>
#include <vnet/tcp/builtin_proxy.h>

builtin_proxy_main_t builtin_proxy_main;

static void
delete_proxy_session (stream_session_t * s, int is_active_open)
{
  builtin_proxy_main_t *bpm = &builtin_proxy_main;
  proxy_session_t *ps = 0;
  vnet_disconnect_args_t _a, *a = &_a;
  stream_session_t *active_open_session = 0;
  stream_session_t *server_session = 0;
  uword *p;
  u64 handle;

  handle = session_handle (s);

  clib_spinlock_lock_if_init (&bpm->sessions_lock);
  if (is_active_open)
    {
      active_open_session = s;

      p = hash_get (bpm->proxy_session_by_active_open_handle, handle);
      if (p == 0)
	{
	  clib_warning ("proxy session for %s handle %lld (%llx) AWOL",
			is_active_open ? "active open" : "server",
			handle, handle);
	}
      else
	{
	  ps = pool_elt_at_index (bpm->sessions, p[0]);
	  if (ps->vpp_server_handle != ~0)
	    server_session = session_get_from_handle (ps->vpp_server_handle);
	  else
	    server_session = 0;
	}
    }
  else
    {
      server_session = s;

      p = hash_get (bpm->proxy_session_by_server_handle, handle);
      if (p == 0)
	{
	  clib_warning ("proxy session for %s handle %lld (%llx) AWOL",
			is_active_open ? "active open" : "server",
			handle, handle);
	}
      else
	{
	  ps = pool_elt_at_index (bpm->sessions, p[0]);
	  if (ps->vpp_server_handle != ~0)
	    active_open_session = session_get_from_handle
	      (ps->vpp_server_handle);
	  else
	    active_open_session = 0;
	}
    }

  if (ps)
    {
      if (CLIB_DEBUG > 0)
	memset (ps, 0xFE, sizeof (*ps));
      pool_put (bpm->sessions, ps);
    }

  clib_spinlock_unlock_if_init (&bpm->sessions_lock);

  if (active_open_session)
    {
      a->handle = session_handle (active_open_session);
      a->app_index = bpm->active_open_app_index;
      hash_unset (bpm->proxy_session_by_active_open_handle,
		  session_handle (active_open_session));
      vnet_disconnect_session (a);
    }

  if (server_session)
    {
      a->handle = session_handle (server_session);
      a->app_index = bpm->server_app_index;
      hash_unset (bpm->proxy_session_by_server_handle,
		  session_handle (server_session));
      vnet_disconnect_session (a);
    }
}

static int
server_accept_callback (stream_session_t * s)
{
  builtin_proxy_main_t *bpm = &builtin_proxy_main;

  s->session_state = SESSION_STATE_READY;

  clib_spinlock_lock_if_init (&bpm->sessions_lock);

  return 0;
}

static void
server_disconnect_callback (stream_session_t * s)
{
  delete_proxy_session (s, 0 /* is_active_open */ );
}

static void
server_reset_callback (stream_session_t * s)
{
  clib_warning ("Reset session %U", format_stream_session, s, 2);
  delete_proxy_session (s, 0 /* is_active_open */ );
}

static int
server_connected_callback (u32 app_index, u32 api_context,
			   stream_session_t * s, u8 is_fail)
{
  clib_warning ("called...");
  return -1;
}

static int
server_add_segment_callback (u32 client_index,
			     const u8 * seg_name, u32 seg_size)
{
  clib_warning ("called...");
  return -1;
}

static int
server_redirect_connect_callback (u32 client_index, void *mp)
{
  clib_warning ("called...");
  return -1;
}

static int
server_rx_callback (stream_session_t * s)
{
  u32 max_dequeue;
  int actual_transfer __attribute__ ((unused));
  svm_fifo_t *tx_fifo, *rx_fifo;
  builtin_proxy_main_t *bpm = &builtin_proxy_main;
  u32 thread_index = vlib_get_thread_index ();
  vnet_connect_args_t _a, *a = &_a;
  proxy_session_t *ps;
  int proxy_index;
  uword *p;
  svm_fifo_t *active_open_tx_fifo;
  session_fifo_event_t evt;

  ASSERT (s->thread_index == thread_index);

  clib_spinlock_lock_if_init (&bpm->sessions_lock);
  p = hash_get (bpm->proxy_session_by_server_handle, session_handle (s));

  if (PREDICT_TRUE (p != 0))
    {
      clib_spinlock_unlock_if_init (&bpm->sessions_lock);
      active_open_tx_fifo = s->server_rx_fifo;

      /*
       * Send event for active open tx fifo
       */
      if (svm_fifo_set_event (active_open_tx_fifo))
	{
	  evt.fifo = active_open_tx_fifo;
	  evt.event_type = FIFO_EVENT_APP_TX;
	  if (svm_queue_add
	      (bpm->active_open_event_queue[thread_index], (u8 *) & evt,
	       0 /* do wait for mutex */ ))
	    clib_warning ("failed to enqueue tx evt");
	}
    }
  else
    {
      rx_fifo = s->server_rx_fifo;
      tx_fifo = s->server_tx_fifo;

      ASSERT (rx_fifo->master_thread_index == thread_index);
      ASSERT (tx_fifo->master_thread_index == thread_index);

      max_dequeue = svm_fifo_max_dequeue (s->server_rx_fifo);

      if (PREDICT_FALSE (max_dequeue == 0))
	return 0;

      actual_transfer = svm_fifo_peek (rx_fifo, 0 /* relative_offset */ ,
				       max_dequeue,
				       bpm->rx_buf[thread_index]);

      /* $$$ your message in this space: parse url, etc. */

      memset (a, 0, sizeof (*a));

      clib_spinlock_lock_if_init (&bpm->sessions_lock);
      pool_get (bpm->sessions, ps);
      memset (ps, 0, sizeof (*ps));
      ps->server_rx_fifo = rx_fifo;
      ps->server_tx_fifo = tx_fifo;
      ps->vpp_server_handle = session_handle (s);

      proxy_index = ps - bpm->sessions;

      hash_set (bpm->proxy_session_by_server_handle, ps->vpp_server_handle,
		proxy_index);

      clib_spinlock_unlock_if_init (&bpm->sessions_lock);

      a->uri = "tcp://6.0.2.2/23";
      a->api_context = proxy_index;
      a->app_index = bpm->active_open_app_index;
      a->mp = 0;
      vnet_connect_uri (a);
    }

  return 0;
}

static session_cb_vft_t builtin_session_cb_vft = {
  .session_accept_callback = server_accept_callback,
  .session_disconnect_callback = server_disconnect_callback,
  .session_connected_callback = server_connected_callback,
  .add_segment_callback = server_add_segment_callback,
  .redirect_connect_callback = server_redirect_connect_callback,
  .builtin_server_rx_callback = server_rx_callback,
  .session_reset_callback = server_reset_callback
};

static int
active_open_connected_callback (u32 app_index, u32 opaque,
				stream_session_t * s, u8 is_fail)
{
  builtin_proxy_main_t *bpm = &builtin_proxy_main;
  proxy_session_t *ps;
  u8 thread_index = vlib_get_thread_index ();
  session_fifo_event_t evt;

  if (is_fail)
    {
      clib_warning ("connection %d failed!", opaque);
      return 0;
    }

  /*
   * Setup proxy session handle.
   */
  clib_spinlock_lock_if_init (&bpm->sessions_lock);

  ps = pool_elt_at_index (bpm->sessions, opaque);
  ps->vpp_active_open_handle = session_handle (s);

  s->server_tx_fifo = ps->server_rx_fifo;
  s->server_rx_fifo = ps->server_tx_fifo;

  /*
   * Reset the active-open tx-fifo master indices so the active-open session
   * will receive data, etc.
   */
  s->server_tx_fifo->master_session_index = s->session_index;
  s->server_tx_fifo->master_thread_index = s->thread_index;

  /*
   * Account for the active-open session's use of the fifos
   * so they won't disappear until the last session which uses
   * them disappears
   */
  s->server_tx_fifo->refcnt++;
  s->server_rx_fifo->refcnt++;

  hash_set (bpm->proxy_session_by_active_open_handle,
	    ps->vpp_active_open_handle, opaque);

  clib_spinlock_unlock_if_init (&bpm->sessions_lock);

  /*
   * Send event for active open tx fifo
   */
  if (svm_fifo_set_event (s->server_tx_fifo))
    {
      evt.fifo = s->server_tx_fifo;
      evt.event_type = FIFO_EVENT_APP_TX;
      if (svm_queue_add
	  (bpm->active_open_event_queue[thread_index], (u8 *) & evt,
	   0 /* do wait for mutex */ ))
	clib_warning ("failed to enqueue tx evt");
    }

  return 0;
}

static void
active_open_reset_callback (stream_session_t * s)
{
  delete_proxy_session (s, 1 /* is_active_open */ );
}

static int
active_open_create_callback (stream_session_t * s)
{
  return 0;
}

static void
active_open_disconnect_callback (stream_session_t * s)
{
  delete_proxy_session (s, 1 /* is_active_open */ );
}

static int
active_open_rx_callback (stream_session_t * s)
{
  builtin_proxy_main_t *bpm = &builtin_proxy_main;
  session_fifo_event_t evt;
  svm_fifo_t *server_rx_fifo;
  u32 thread_index = vlib_get_thread_index ();

  server_rx_fifo = s->server_rx_fifo;

  /*
   * Send event for server tx fifo
   */
  if (svm_fifo_set_event (server_rx_fifo))
    {
      evt.fifo = server_rx_fifo;
      evt.event_type = FIFO_EVENT_APP_TX;
      if (svm_queue_add
	  (bpm->server_event_queue[thread_index], (u8 *) & evt,
	   0 /* do wait for mutex */ ))
	clib_warning ("failed to enqueue server rx evt");
    }

  return 0;
}

/* *INDENT-OFF* */
static session_cb_vft_t builtin_clients = {
  .session_reset_callback = active_open_reset_callback,
  .session_connected_callback = active_open_connected_callback,
  .session_accept_callback = active_open_create_callback,
  .session_disconnect_callback = active_open_disconnect_callback,
  .builtin_server_rx_callback = active_open_rx_callback
};
/* *INDENT-ON* */


static void
create_api_loopbacks (vlib_main_t * vm)
{
  builtin_proxy_main_t *bpm = &builtin_proxy_main;
  api_main_t *am = &api_main;
  vl_shmem_hdr_t *shmem_hdr;

  shmem_hdr = am->shmem_hdr;
  bpm->vl_input_queue = shmem_hdr->vl_input_queue;
  bpm->server_client_index =
    vl_api_memclnt_create_internal ("proxy_server", bpm->vl_input_queue);
  bpm->active_open_client_index =
    vl_api_memclnt_create_internal ("proxy_active_open", bpm->vl_input_queue);
}

static int
server_attach ()
{
  builtin_proxy_main_t *bpm = &builtin_proxy_main;
  u8 segment_name[128];
  u64 options[APP_OPTIONS_N_OPTIONS];
  vnet_app_attach_args_t _a, *a = &_a;
  u32 segment_size = 512 << 20;

  memset (a, 0, sizeof (*a));
  memset (options, 0, sizeof (options));

  if (bpm->private_segment_size)
    segment_size = bpm->private_segment_size;
  a->api_client_index = bpm->server_client_index;
  a->session_cb_vft = &builtin_session_cb_vft;
  a->options = options;
  a->options[APP_OPTIONS_SEGMENT_SIZE] = segment_size;
  a->options[APP_OPTIONS_RX_FIFO_SIZE] = bpm->fifo_size;
  a->options[APP_OPTIONS_TX_FIFO_SIZE] = bpm->fifo_size;
  a->options[APP_OPTIONS_PRIVATE_SEGMENT_COUNT] = bpm->private_segment_count;
  a->options[APP_OPTIONS_PREALLOC_FIFO_PAIRS] =
    bpm->prealloc_fifos ? bpm->prealloc_fifos : 1;

  a->options[APP_OPTIONS_FLAGS] = APP_OPTIONS_FLAGS_IS_BUILTIN;

  a->segment_name = segment_name;
  a->segment_name_length = ARRAY_LEN (segment_name);

  if (vnet_application_attach (a))
    {
      clib_warning ("failed to attach server");
      return -1;
    }
  bpm->server_app_index = a->app_index;

  return 0;
}

static int
active_open_attach (void)
{
  builtin_proxy_main_t *bpm = &builtin_proxy_main;
  vnet_app_attach_args_t _a, *a = &_a;
  u8 segment_name[128];
  u32 segment_name_length;
  u64 options[16];

  segment_name_length = ARRAY_LEN (segment_name);

  memset (a, 0, sizeof (*a));
  memset (options, 0, sizeof (options));

  a->api_client_index = bpm->active_open_client_index;
  a->segment_name = segment_name;
  a->segment_name_length = segment_name_length;
  a->session_cb_vft = &builtin_clients;

  options[APP_OPTIONS_ACCEPT_COOKIE] = 0x12345678;
  options[APP_OPTIONS_SEGMENT_SIZE] = 512 << 20;
  options[APP_OPTIONS_RX_FIFO_SIZE] = bpm->fifo_size;
  options[APP_OPTIONS_TX_FIFO_SIZE] = bpm->fifo_size;
  options[APP_OPTIONS_PRIVATE_SEGMENT_COUNT] = bpm->private_segment_count;
  options[APP_OPTIONS_PREALLOC_FIFO_PAIRS] =
    bpm->prealloc_fifos ? bpm->prealloc_fifos : 1;

  options[APP_OPTIONS_FLAGS] = APP_OPTIONS_FLAGS_IS_BUILTIN
    | APP_OPTIONS_FLAGS_IS_PROXY;

  a->options = options;

  if (vnet_application_attach (a))
    return -1;

  bpm->active_open_app_index = a->app_index;

  return 0;
}

static int
server_listen ()
{
  builtin_proxy_main_t *bpm = &builtin_proxy_main;
  vnet_bind_args_t _a, *a = &_a;
  memset (a, 0, sizeof (*a));
  a->app_index = bpm->server_app_index;
  a->uri = "tcp://0.0.0.0/23";
  return vnet_bind_uri (a);
}

static int
server_create (vlib_main_t * vm)
{
  builtin_proxy_main_t *bpm = &builtin_proxy_main;
  vlib_thread_main_t *vtm = vlib_get_thread_main ();
  u32 num_threads;
  int i;

  if (bpm->server_client_index == (u32) ~ 0)
    create_api_loopbacks (vm);

  num_threads = 1 /* main thread */  + vtm->n_threads;
  vec_validate (builtin_proxy_main.server_event_queue, num_threads - 1);
  vec_validate (builtin_proxy_main.active_open_event_queue, num_threads - 1);
  vec_validate (bpm->rx_buf, num_threads - 1);

  for (i = 0; i < num_threads; i++)
    vec_validate (bpm->rx_buf[i], bpm->rcv_buffer_size);

  if (server_attach ())
    {
      clib_warning ("failed to attach server app");
      return -1;
    }
  if (server_listen ())
    {
      clib_warning ("failed to start listening");
      return -1;
    }
  if (active_open_attach ())
    {
      clib_warning ("failed to attach active open app");
      return -1;
    }

  for (i = 0; i < num_threads; i++)
    {
      bpm->active_open_event_queue[i] =
	session_manager_get_vpp_event_queue (i);

      ASSERT (bpm->active_open_event_queue[i]);

      bpm->server_event_queue[i] = session_manager_get_vpp_event_queue (i);
    }

  return 0;
}

static clib_error_t *
proxy_server_create_command_fn (vlib_main_t * vm, unformat_input_t * input,
				vlib_cli_command_t * cmd)
{
  builtin_proxy_main_t *bpm = &builtin_proxy_main;
  int rv;
  u64 tmp;

  bpm->fifo_size = 64 << 10;
  bpm->rcv_buffer_size = 1024;
  bpm->prealloc_fifos = 0;
  bpm->private_segment_count = 0;
  bpm->private_segment_size = 0;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (input, "fifo-size %d", &bpm->fifo_size))
	bpm->fifo_size <<= 10;
      else if (unformat (input, "rcv-buf-size %d", &bpm->rcv_buffer_size))
	;
      else if (unformat (input, "prealloc-fifos %d", &bpm->prealloc_fifos))
	;
      else if (unformat (input, "private-segment-count %d",
			 &bpm->private_segment_count))
	;
      else if (unformat (input, "private-segment-size %U",
			 unformat_memory_size, &tmp))
	{
	  if (tmp >= 0x100000000ULL)
	    return clib_error_return
	      (0, "private segment size %lld (%llu) too large", tmp, tmp);
	  bpm->private_segment_size = tmp;
	}
      else
	return clib_error_return (0, "unknown input `%U'",
				  format_unformat_error, input);
    }

  vnet_session_enable_disable (vm, 1 /* turn on TCP, etc. */ );

  rv = server_create (vm);
  switch (rv)
    {
    case 0:
      break;
    default:
      return clib_error_return (0, "server_create returned %d", rv);
    }

  return 0;
}

/* *INDENT-OFF* */
VLIB_CLI_COMMAND (server_create_command, static) =
{
  .path = "test proxy server",
  .short_help = "test proxy server",
  .function = proxy_server_create_command_fn,
};
/* *INDENT-ON* */

clib_error_t *
builtin_tcp_proxy_main_init (vlib_main_t * vm)
{
  builtin_proxy_main_t *bpm = &builtin_proxy_main;
  bpm->server_client_index = ~0;
  bpm->active_open_client_index = ~0;
  bpm->proxy_session_by_active_open_handle = hash_create (0, sizeof (uword));
  bpm->proxy_session_by_server_handle = hash_create (0, sizeof (uword));

  return 0;
}

VLIB_INIT_FUNCTION (builtin_tcp_proxy_main_init);

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