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/*
 * Copyright (c) 2015 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.
 */
#ifndef included_clib_mhash_h
#define included_clib_mhash_h

/*
  Copyright (c) 2010 Eliot Dresselhaus

  Permission is hereby granted, free of charge, to any person obtaining
  a copy of this software and associated documentation files (the
  "Software"), to deal in the Software without restriction, including
  without limitation the rights to use, copy, modify, merge, publish,
  distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so, subject to
  the following conditions:

  The above copyright notice and this permission notice shall be
  included in all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#include <vppinfra/format.h>
#include <vppinfra/hash.h>
#include <vppinfra/heap.h>

/* Hash table plus vector of keys. */
typedef struct
{
  /* Vector or heap used to store keys.  Hash table stores keys as byte
     offsets into this vector. */
  u8 *key_vector_or_heap;

  /* Byte offsets of free keys in vector (used to store free keys when
     n_key_bytes > 1). */
  u32 *key_vector_free_indices;

  u8 **key_tmps;

  /* Possibly fixed size of key.
     0 means keys are vectors of u8's.
     1 means keys are null terminated c strings. */
#define MHASH_VEC_STRING_KEY 0
#define MHASH_C_STRING_KEY 1
  u32 n_key_bytes;

  /* Seed value for Jenkins hash. */
  u32 hash_seed;

  /* Hash table mapping key -> value. */
  uword *hash;

  /* Format function for keys. */
  format_function_t *format_key;
} mhash_t;

void mhash_init (mhash_t * h, uword n_value_bytes, uword n_key_bytes);

always_inline void
mhash_init_c_string (mhash_t * h, uword n_value_bytes)
{
  mhash_init (h, n_value_bytes, MHASH_C_STRING_KEY);
}

always_inline void
mhash_init_vec_string (mhash_t * h, uword n_value_bytes)
{
  mhash_init (h, n_value_bytes, MHASH_VEC_STRING_KEY);
}

always_inline void *
mhash_key_to_mem (mhash_t * h, uword key)
{
  if (key == ~0)
    {
      u8 *key_tmp;

      int my_cpu = os_get_thread_index ();
      vec_validate (h->key_tmps, my_cpu);
      key_tmp = h->key_tmps[my_cpu];
      return key_tmp;
    }
  return vec_elt_at_index (h->key_vector_or_heap, key);
}

hash_pair_t *mhash_get_pair (mhash_t * h, const void *key);
uword mhash_set_mem (mhash_t * h, void *key, uword * new_value,
		     uword * old_value);
uword mhash_unset (mhash_t * h, void *key, uword * old_value);

always_inline uword *
mhash_get (mhash_t * h, const void *key)
{
  hash_pair_t *p = mhash_get_pair (h, key);
  return p ? &p->value[0] : 0;
}

always_inline uword
mhash_set (mhash_t * h, void *key, uword new_value, uword * old_value)
{
  return mhash_set_mem (h, key, &new_value, old_value);
}

always_inline uword
mhash_unset_key (mhash_t * h, uword key, uword * old_value)
{
  void *k = mhash_key_to_mem (h, key);
  return mhash_unset (h, k, old_value);
}

always_inline uword
mhash_value_bytes (mhash_t * m)
{
  hash_t *h = hash_header (m->hash);
  return hash_value_bytes (h);
}

always_inline uword
mhash_elts (mhash_t * m)
{
  return hash_elts (m->hash);
}

always_inline uword
mhash_key_vector_is_heap (mhash_t * h)
{
  return h->n_key_bytes <= 1;
}

always_inline void
mhash_free (mhash_t * h)
{
  if (mhash_key_vector_is_heap (h))
    heap_free (h->key_vector_or_heap);
  else
    vec_free (h->key_vector_or_heap);
  vec_free (h->key_vector_free_indices);
  hash_free (h->hash);
}

#define mhash_foreach(k,v,mh,body)				\
do {								\
  hash_pair_t * _mhash_foreach_p;				\
  hash_foreach_pair (_mhash_foreach_p, (mh)->hash, ({		\
    (k) = mhash_key_to_mem ((mh), _mhash_foreach_p->key);	\
    (v) = &_mhash_foreach_p->value[0];				\
    body;							\
  }));								\
} while (0)

format_function_t format_mhash_key;

#endif /* included_clib_mhash_h */

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/*
 * Copyright (c) 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.
 */
/**
 * @file
 * @brief Session and session manager
 */

#include <vnet/session/session.h>
#include <vnet/session/session_debug.h>
#include <vnet/session/application.h>
#include <vlibmemory/api.h>
#include <vnet/dpo/load_balance.h>
#include <vnet/fib/ip4_fib.h>
#include <vnet/tcp/tcp.h>

session_manager_main_t session_manager_main;
extern transport_proto_vft_t *tp_vfts;

int
stream_session_create_i (segment_manager_t * sm, transport_connection_t * tc,
			 stream_session_t ** ret_s)
{
  session_manager_main_t *smm = &session_manager_main;
  svm_fifo_t *server_rx_fifo = 0, *server_tx_fifo = 0;
  u32 fifo_segment_index;
  u32 pool_index;
  stream_session_t *s;
  u64 value;
  u32 thread_index = tc->thread_index;
  int rv;

  ASSERT (thread_index == vlib_get_thread_index ());

  if ((rv = segment_manager_alloc_session_fifos (sm, &server_rx_fifo,
						 &server_tx_fifo,
						 &fifo_segment_index)))
    return rv;

  /* Create the session */
  pool_get_aligned (smm->sessions[thread_index], s, CLIB_CACHE_LINE_BYTES);
  memset (s, 0, sizeof (*s));

  /* Initialize backpointers */
  pool_index = s - smm->sessions[thread_index];
  server_rx_fifo->master_session_index = pool_index;
  server_rx_fifo->master_thread_index = thread_index;

  server_tx_fifo->master_session_index = pool_index;
  server_tx_fifo->master_thread_index = thread_index;

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

  /* Initialize state machine, such as it is... */
  s->session_type = tc->proto;
  s->session_state = SESSION_STATE_CONNECTING;
  s->svm_segment_index = fifo_segment_index;
  s->thread_index = thread_index;
  s->session_index = pool_index;

  /* Attach transport to session */
  s->connection_index = tc->c_index;

  /* Attach session to transport */
  tc->s_index = s->session_index;

  /* Add to the main lookup table */
  value = stream_session_handle (s);
  stream_session_table_add_for_tc (tc, value);

  *ret_s = s;

  return 0;
}

/** Enqueue buffer chain tail */
always_inline int
session_enqueue_chain_tail (stream_session_t * s, vlib_buffer_t * b,
			    u32 offset, u8 is_in_order)
{
  vlib_buffer_t *chain_b;
  u32 chain_bi = b->next_buffer;
  vlib_main_t *vm = vlib_get_main ();
  u8 *data, len;
  u16 written = 0;
  int rv = 0;

  do
    {
      chain_b = vlib_get_buffer (vm, chain_bi);
      data = vlib_buffer_get_current (chain_b);
      len = chain_b->current_length;
      if (is_in_order)
	{
	  rv = svm_fifo_enqueue_nowait (s->server_rx_fifo, len, data);
	  if (rv < len)
	    {
	      return (rv > 0) ? (written + rv) : written;
	    }
	  written += rv;
	}
      else
	{
	  rv = svm_fifo_enqueue_with_offset (s->server_rx_fifo, offset, len,
					     data);
	  if (rv)
	    return -1;
	  offset += len;
	}
    }
  while ((chain_bi = (chain_b->flags & VLIB_BUFFER_NEXT_PRESENT)
	  ? chain_b->next_buffer : 0));

  if (is_in_order)
    return written;

  return 0;
}

/*
 * Enqueue data for delivery to session peer. Does not notify peer of enqueue
 * event but on request can queue notification events for later delivery by
 * calling stream_server_flush_enqueue_events().
 *
 * @param tc Transport connection which is to be enqueued data
 * @param b Buffer to be enqueued
 * @param offset Offset at which to start enqueueing if out-of-order
 * @param queue_event Flag to indicate if peer is to be notified or if event
 *                    is to be queued. The former is useful when more data is
 *                    enqueued and only one event is to be generated.
 * @param is_in_order Flag to indicate if data is in order
 * @return Number of bytes enqueued or a negative value if enqueueing failed.
 */
int
stream_session_enqueue_data (transport_connection_t * tc, vlib_buffer_t * b,
			     u32 offset, u8 queue_event, u8 is_in_order)
{
  stream_session_t *s;
  int enqueued = 0, rv;

  s = stream_session_get (tc->s_index, tc->thread_index);

  if (is_in_order)
    {
      enqueued =
	svm_fifo_enqueue_nowait (s->server_rx_fifo, b->current_length,
				 vlib_buffer_get_current (b));
      if (PREDICT_FALSE
	  ((b->flags & VLIB_BUFFER_NEXT_PRESENT) && enqueued > 0))
	{
	  rv = session_enqueue_chain_tail (s, b, 0, 1);
	  if (rv <= 0)
	    return enqueued;
	  enqueued += rv;
	}
    }
  else
    {
      rv = svm_fifo_enqueue_with_offset (s->server_rx_fifo, offset,
					 b->current_length,
					 vlib_buffer_get_current (b));
      if (PREDICT_FALSE ((b->flags & VLIB_BUFFER_NEXT_PRESENT) && !rv))
	rv = session_enqueue_chain_tail (s, b, offset + b->current_length, 0);
      if (rv)
	return -1;
    }

  if (queue_event)
    {
      /* Queue RX event on this fifo. Eventually these will need to be flushed
       * by calling stream_server_flush_enqueue_events () */
      session_manager_main_t *smm = vnet_get_session_manager_main ();
      u32 thread_index = s->thread_index;
      u32 my_enqueue_epoch = smm->current_enqueue_epoch[thread_index];

      if (s->enqueue_epoch != my_enqueue_epoch)
	{
	  s->enqueue_epoch = my_enqueue_epoch;
	  vec_add1 (smm->session_indices_to_enqueue_by_thread[thread_index],
		    s - smm->sessions[thread_index]);
	}
    }

  if (is_in_order)
    return enqueued;

  return 0;
}

/** Check if we have space in rx fifo to push more bytes */
u8
stream_session_no_space (transport_connection_t * tc, u32 thread_index,
			 u16 data_len)
{
  stream_session_t *s = stream_session_get (tc->s_index, thread_index);

  if (PREDICT_FALSE (s->session_state != SESSION_STATE_READY))
    return 1;

  if (data_len > svm_fifo_max_enqueue (s->server_rx_fifo))
    return 1;

  return 0;
}

u32
stream_session_tx_fifo_max_dequeue (transport_connection_t * tc)
{
  stream_session_t *s = stream_session_get (tc->s_index, tc->thread_index);
  if (s->session_state != SESSION_STATE_READY)
    return 0;
  return svm_fifo_max_dequeue (s->server_tx_fifo);
}

int
stream_session_peek_bytes (transport_connection_t * tc, u8 * buffer,
			   u32 offset, u32 max_bytes)
{
  stream_session_t *s = stream_session_get (tc->s_index, tc->thread_index);
  return svm_fifo_peek (s->server_tx_fifo, offset, max_bytes, buffer);
}

u32
stream_session_dequeue_drop (transport_connection_t * tc, u32 max_bytes)
{
  stream_session_t *s = stream_session_get (tc->s_index, tc->thread_index);
  return svm_fifo_dequeue_drop (s->server_tx_fifo, max_bytes);
}

/**
 * Notify session peer that new data has been enqueued.
 *
 * @param s Stream session for which the event is to be generated.
 * @param block Flag to indicate if call should block if event queue is full.
 *
 * @return 0 on succes or negative number if failed to send notification.
 */
static int
stream_session_enqueue_notify (stream_session_t * s, u8 block)
{
  application_t *app;
  session_fifo_event_t evt;
  unix_shared_memory_queue_t *q;
  static u32 serial_number;

  if (PREDICT_FALSE (s->session_state == SESSION_STATE_CLOSED))
    return 0;

  /* Get session's server */
  app = application_get (s->app_index);

  /* Built-in server? Hand event to the callback... */
  if (app->cb_fns.builtin_server_rx_callback)
    return app->cb_fns.builtin_server_rx_callback (s);

  /* If no event, send one */
  if (svm_fifo_set_event (s->server_rx_fifo))
    {
      /* Fabricate event */
      evt.fifo = s->server_rx_fifo;
      evt.event_type = FIFO_EVENT_APP_RX;
      evt.event_id = serial_number++;

      /* Add event to server's event queue */
      q = app->event_queue;

      /* Based on request block (or not) for lack of space */
      if (block || PREDICT_TRUE (q->cursize < q->maxsize))
	unix_shared_memory_queue_add (app->event_queue, (u8 *) & evt,
				      0 /* do wait for mutex */ );
      else
	{
	  clib_warning ("fifo full");
	  return -1;
	}
    }

  /* *INDENT-OFF* */
  SESSION_EVT_DBG(SESSION_EVT_ENQ, s, ({
      ed->data[0] = evt.event_id;
      ed->data[1] = svm_fifo_max_dequeue (s->server_rx_fifo);
  }));
  /* *INDENT-ON* */

  return 0;
}

/**
 * Flushes queue of sessions that are to be notified of new data
 * enqueued events.
 *
 * @param thread_index Thread index for which the flush is to be performed.
 * @return 0 on success or a positive number indicating the number of
 *         failures due to API queue being full.
 */
int
session_manager_flush_enqueue_events (u32 thread_index)
{
  session_manager_main_t *smm = &session_manager_main;
  u32 *session_indices_to_enqueue;
  int i, errors = 0;

  session_indices_to_enqueue =
    smm->session_indices_to_enqueue_by_thread[thread_index];

  for (i = 0; i < vec_len (session_indices_to_enqueue); i++)
    {
      stream_session_t *s0;

      /* Get session */
      s0 = stream_session_get (session_indices_to_enqueue[i], thread_index);
      if (stream_session_enqueue_notify (s0, 0 /* don't block */ ))
	{
	  errors++;
	}
    }

  vec_reset_length (session_indices_to_enqueue);

  smm->session_indices_to_enqueue_by_thread[thread_index] =
    session_indices_to_enqueue;

  /* Increment enqueue epoch for next round */
  smm->current_enqueue_epoch[thread_index]++;

  return errors;
}

/**
 * Init fifo tail and head pointers
 *
 * Useful if transport uses absolute offsets for tracking ooo segments.
 */
void
stream_session_init_fifos_pointers (transport_connection_t * tc,
				    u32 rx_pointer, u32 tx_pointer)
{
  stream_session_t *s;
  s = stream_session_get (tc->s_index, tc->thread_index);
  svm_fifo_init_pointers (s->server_rx_fifo, rx_pointer);
  svm_fifo_init_pointers (s->server_tx_fifo, tx_pointer);
}

int
stream_session_connect_notify (transport_connection_t * tc, u8 sst,
			       u8 is_fail)
{
  application_t *app;
  stream_session_t *new_s = 0;
  u64 handle;
  u32 api_context = 0;
  int error = 0;

  handle = stream_session_half_open_lookup_handle (&tc->lcl_ip, &tc->rmt_ip,
						   tc->lcl_port, tc->rmt_port,
						   tc->proto);
  if (handle == HALF_OPEN_LOOKUP_INVALID_VALUE)
    {
      clib_warning ("This can't be good!");
      return -1;
    }

  /* Get the app's index from the handle we stored when opening connection */
  app = application_get (handle >> 32);
  api_context = tc->s_index;

  if (!is_fail)
    {
      segment_manager_t *sm;
      sm = application_get_connect_segment_manager (app);

      /* Create new session (svm segments are allocated if needed) */
      if (stream_session_create_i (sm, tc, &new_s))
	{
	  is_fail = 1;
	  error = -1;
	}
      else
	new_s->app_index = app->index;
    }

  /* Notify client */
  if (app->cb_fns.session_connected_callback (app->index, api_context, new_s,
					      is_fail))
    {
      clib_warning ("failed to notify app");
      if (!is_fail)
	stream_session_disconnect (new_s);
    }
  else
    {
      if (!is_fail)
	new_s->session_state = SESSION_STATE_READY;
    }

  /* Cleanup session lookup */
  stream_session_half_open_table_del (sst, tc);

  return error;
}

void
stream_session_accept_notify (transport_connection_t * tc)
{
  application_t *server;
  stream_session_t *s;

  s = stream_session_get (tc->s_index, tc->thread_index);
  server = application_get (s->app_index);
  server->cb_fns.session_accept_callback (s);
}

/**
 * Notification from transport that connection is being closed.
 *
 * A disconnect is sent to application but state is not removed. Once
 * disconnect is acknowledged by application, session disconnect is called.
 * Ultimately this leads to close being called on transport (passive close).
 */
void
stream_session_disconnect_notify (transport_connection_t * tc)
{
  application_t *server;
  stream_session_t *s;

  s = stream_session_get (tc->s_index, tc->thread_index);
  server = application_get (s->app_index);
  server->cb_fns.session_disconnect_callback (s);
}

/**
 * Cleans up session and associated app if needed.
 */
void
stream_session_delete (stream_session_t * s)
{
  session_manager_main_t *smm = vnet_get_session_manager_main ();
  int rv;

  /* Delete from the main lookup table. */
  if ((rv = stream_session_table_del (s)))
    clib_warning ("hash delete error, rv %d", rv);

  /* Cleanup fifo segments */
  segment_manager_dealloc_fifos (s->svm_segment_index, s->server_rx_fifo,
				 s->server_tx_fifo);

  pool_put (smm->sessions[s->thread_index], s);
  if (CLIB_DEBUG)
    memset (s, 0xFA, sizeof (*s));
}

/**
 * Notification from transport that connection is being deleted
 *
 * This should be called only on previously fully established sessions. For
 * instance failed connects should call stream_session_connect_notify and
 * indicate that the connect has failed.
 */
void
stream_session_delete_notify (transport_connection_t * tc)
{
  stream_session_t *s;

  /* App might've been removed already */
  s = stream_session_get_if_valid (tc->s_index, tc->thread_index);
  if (!s)
    {
      return;
    }
  stream_session_delete (s);
}

/**
 * Notify application that connection has been reset.
 */
void
stream_session_reset_notify (transport_connection_t * tc)
{
  stream_session_t *s;
  application_t *app;
  s = stream_session_get (tc->s_index, tc->thread_index);

  app = application_get (s->app_index);
  app->cb_fns.session_reset_callback (s);
}

/**
 * Accept a stream session. Optionally ping the server by callback.
 */
int
stream_session_accept (transport_connection_t * tc, u32 listener_index,
		       u8 sst, u8 notify)
{
  application_t *server;
  stream_session_t *s, *listener;
  segment_manager_t *sm;

  int rv;

  /* Find the server */
  listener = listen_session_get (sst, listener_index);
  server = application_get (listener->app_index);

  sm = application_get_listen_segment_manager (server, listener);
  if ((rv = stream_session_create_i (sm, tc, &s)))
    return rv;

  s->app_index = server->index;
  s->listener_index = listener_index;
  s->session_state = SESSION_STATE_ACCEPTING;

  /* Shoulder-tap the server */
  if (notify)
    {
      server->cb_fns.session_accept_callback (s);
    }

  return 0;
}

/**
 * Ask transport to open connection to remote transport endpoint.
 *
 * Stores handle for matching request with reply since the call can be
 * asynchronous. For instance, for TCP the 3-way handshake must complete
 * before reply comes. Session is only created once connection is established.
 *
 * @param app_index Index of the application requesting the connect
 * @param st Session type requested.
 * @param tep Remote transport endpoint
 * @param res Resulting transport connection .
 */
int
stream_session_open (u32 app_index, session_type_t st,
		     transport_endpoint_t * rmt,
		     transport_connection_t ** res)
{
  transport_connection_t *tc;
  int rv;
  u64 handle;

  rv = tp_vfts[st].open (rmt);
  if (rv < 0)
    {
      clib_warning ("Transport failed to open connection.");
      return VNET_API_ERROR_SESSION_CONNECT_FAIL;
    }

  tc = tp_vfts[st].get_half_open ((u32) rv);

  /* Save app and tc index. The latter is needed to help establish the
   * connection while the former is needed when the connect notify comes
   * and we have to notify the external app */
  handle = (((u64) app_index) << 32) | (u64) tc->c_index;

  /* Add to the half-open lookup table */
  stream_session_half_open_table_add (st, tc, handle);

  *res = tc;

  return 0;
}

/**
 * Ask transport to listen on local transport endpoint.
 *
 * @param s Session for which listen will be called. Note that unlike
 * 	    established sessions, listen sessions are not associated to a
 * 	    thread.
 * @param tep Local endpoint to be listened on.
 */
int
stream_session_listen (stream_session_t * s, transport_endpoint_t * tep)
{
  transport_connection_t *tc;
  u32 tci;

  /* Transport bind/listen  */
  tci = tp_vfts[s->session_type].bind (s->session_index, tep);

  if (tci == (u32) ~ 0)
    return -1;

  /* Attach transport to session */
  s->connection_index = tci;
  tc = tp_vfts[s->session_type].get_listener (tci);

  /* Weird but handle it ... */
  if (tc == 0)
    return -1;

  /* Add to the main lookup table */
  stream_session_table_add_for_tc (tc, s->session_index);

  return 0;
}

/**
 * Ask transport to stop listening on local transport endpoint.
 *
 * @param s Session to stop listening on. It must be in state LISTENING.
 */
int
stream_session_stop_listen (stream_session_t * s)
{
  transport_connection_t *tc;

  if (s->session_state != SESSION_STATE_LISTENING)
    {
      clib_warning ("not a listening session");
      return -1;
    }

  tc = tp_vfts[s->session_type].get_listener (s->connection_index);
  if (!tc)
    {
      clib_warning ("no transport");
      return VNET_API_ERROR_ADDRESS_NOT_IN_USE;
    }

  stream_session_table_del_for_tc (tc);
  tp_vfts[s->session_type].unbind (s->connection_index);
  return 0;
}

void
session_send_session_evt_to_thread (u64 session_handle,
				    fifo_event_type_t evt_type,
				    u32 thread_index)
{
  static u16 serial_number = 0;
  session_fifo_event_t evt;
  unix_shared_memory_queue_t *q;

  /* Fabricate event */
  evt.session_handle = session_handle;
  evt.event_type = evt_type;
  evt.event_id = serial_number++;

  q = session_manager_get_vpp_event_queue (thread_index);

  /* Based on request block (or not) for lack of space */
  if (PREDICT_TRUE (q->cursize < q->maxsize))
    {
      if (unix_shared_memory_queue_add (q, (u8 *) & evt,
					1 /* do wait for mutex */ ))
	{
	  clib_warning ("failed to enqueue evt");
	}
    }
  else
    {
      clib_warning ("queue full");
      return;
    }
}

/**
 * Disconnect session and propagate to transport. This should eventually
 * result in a delete notification that allows us to cleanup session state.
 * Called for both active/passive disconnects.
 *
 * Should be called from the session's thread.
 */
void
stream_session_disconnect (stream_session_t * s)
{
  s->session_state = SESSION_STATE_CLOSED;
  tp_vfts[s->session_type].close (s->connection_index, s->thread_index);
}

/**
 * Cleanup transport and session state.
 *
 * Notify transport of the cleanup, wait for a delete notify to actually
 * remove the session state.
 */
void
stream_session_cleanup (stream_session_t * s)
{
  int rv;

  s->session_state = SESSION_STATE_CLOSED;

  /* Delete from the main lookup table to avoid more enqueues */
  rv = stream_session_table_del (s);
  if (rv)
    clib_warning ("hash delete error, rv %d", rv);

  tp_vfts[s->session_type].cleanup (s->connection_index, s->thread_index);
}

/**
 * Allocate vpp event queue (once) per worker thread
 */
void
session_vpp_event_queue_allocate (session_manager_main_t * smm,
				  u32 thread_index)
{
  api_main_t *am = &api_main;
  void *oldheap;
  u32 event_queue_length = 2048;

  if (smm->vpp_event_queues[thread_index] == 0)
    {
      /* Allocate event fifo in the /vpe-api shared-memory segment */
      oldheap = svm_push_data_heap (am->vlib_rp);

      if (smm->configured_event_queue_length)
	event_queue_length = smm->configured_event_queue_length;

      smm->vpp_event_queues[thread_index] =
	unix_shared_memory_queue_init
	(event_queue_length,
	 sizeof (session_fifo_event_t), 0 /* consumer pid */ ,
	 0 /* (do not) send signal when queue non-empty */ );

      svm_pop_heap (oldheap);
    }
}

session_type_t
session_type_from_proto_and_ip (transport_proto_t proto, u8 is_ip4)
{
  if (proto == TRANSPORT_PROTO_TCP)
    {
      if (is_ip4)
	return SESSION_TYPE_IP4_TCP;
      else
	return SESSION_TYPE_IP6_TCP;
    }
  else
    {
      if (is_ip4)
	return SESSION_TYPE_IP4_UDP;
      else
	return SESSION_TYPE_IP6_UDP;
    }

  return SESSION_N_TYPES;
}

static clib_error_t *
session_manager_main_enable (vlib_main_t * vm)
{
  session_manager_main_t *smm = &session_manager_main;
  vlib_thread_main_t *vtm = vlib_get_thread_main ();
  u32 num_threads;
  int i;

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

  if (num_threads < 1)
    return clib_error_return (0, "n_thread_stacks not set");

  /* $$$ config parameters */
  svm_fifo_segment_init (0x200000000ULL /* first segment base VA */ ,
			 20 /* timeout in seconds */ );

  /* configure per-thread ** vectors */
  vec_validate (smm->sessions, num_threads - 1);
  vec_validate (smm->session_indices_to_enqueue_by_thread, num_threads - 1);
  vec_validate (smm->tx_buffers, num_threads - 1);
  vec_validate (smm->pending_event_vector, num_threads - 1);
  vec_validate (smm->free_event_vector, num_threads - 1);
  vec_validate (smm->current_enqueue_epoch, num_threads - 1);
  vec_validate (smm->vpp_event_queues, num_threads - 1);

  for (i = 0; i < num_threads; i++)
    {
      vec_validate (smm->free_event_vector[i], 0);
      _vec_len (smm->free_event_vector[i]) = 0;
      vec_validate (smm->pending_event_vector[i], 0);
      _vec_len (smm->pending_event_vector[i]) = 0;
    }

#if SESSION_DBG
  vec_validate (smm->last_event_poll_by_thread, num_threads - 1);
#endif

  /* Allocate vpp event queues */
  for (i = 0; i < vec_len (smm->vpp_event_queues); i++)
    session_vpp_event_queue_allocate (smm, i);

  /* $$$$ preallocate hack config parameter */
  for (i = 0; i < smm->preallocated_sessions; i++)
    {
      stream_session_t *ss __attribute__ ((unused));
      pool_get_aligned (smm->sessions[0], ss, CLIB_CACHE_LINE_BYTES);
    }

  for (i = 0; i < smm->preallocated_sessions; i++)
    pool_put_index (smm->sessions[0], i);

  session_lookup_init ();

  smm->is_enabled = 1;

  /* Enable TCP transport */
  vnet_tcp_enable_disable (vm, 1);

  return 0;
}

void
session_node_enable_disable (u8 is_en)
{
  u8 state = is_en ? VLIB_NODE_STATE_POLLING : VLIB_NODE_STATE_DISABLED;
  /* *INDENT-OFF* */
  foreach_vlib_main (({
    vlib_node_set_state (this_vlib_main, session_queue_node.index,
                         state);
  }));
  /* *INDENT-ON* */
}

clib_error_t *
vnet_session_enable_disable (vlib_main_t * vm, u8 is_en)
{
  if (is_en)
    {
      if (session_manager_main.is_enabled)
	return 0;

      session_node_enable_disable (is_en);

      return session_manager_main_enable (vm);
    }
  else
    {
      session_manager_main.is_enabled = 0;
      session_node_enable_disable (is_en);
    }

  return 0;
}

clib_error_t *
session_manager_main_init (vlib_main_t * vm)
{
  session_manager_main_t *smm = &session_manager_main;
  smm->is_enabled = 0;
  return 0;
}

VLIB_INIT_FUNCTION (session_manager_main_init);

static clib_error_t *
session_config_fn (vlib_main_t * vm, unformat_input_t * input)
{
  session_manager_main_t *smm = &session_manager_main;
  u32 nitems;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (input, "event-queue-length %d", &nitems))
	{
	  if (nitems >= 2048)
	    smm->configured_event_queue_length = nitems;
	  else
	    clib_warning ("event queue length %d too small, ignored", nitems);
	}
      if (unformat (input, "preallocated-sessions %d",
		    &smm->preallocated_sessions))
	;
      else
	return clib_error_return (0, "unknown input `%U'",
				  format_unformat_error, input);
    }
  return 0;
}

VLIB_CONFIG_FUNCTION (session_config_fn, "session");

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