text: /*
   * 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.
   */
  #ifndef __included_session_h__
  #define __included_session_h__
  
  #include <vnet/session/stream_session.h>
  #include <vnet/session/session_lookup.h>
  #include <vnet/session/transport_interface.h>
  #include <vlibmemory/unix_shared_memory_queue.h>
  #include <vnet/session/session_debug.h>
  #include <vnet/session/segment_manager.h>
  
  #define HALF_OPEN_LOOKUP_INVALID_VALUE ((u64)~0)
  #define INVALID_INDEX ((u32)~0)
  #define SESSION_PROXY_LISTENER_INDEX ((u32)~0 - 1)
  
  /* TODO decide how much since we have pre-data as well */
  #define MAX_HDRS_LEN    100	/* Max number of bytes for headers */
  
  typedef enum
  {
    FIFO_EVENT_APP_RX,
    FIFO_EVENT_APP_TX,
    FIFO_EVENT_TIMEOUT,
    FIFO_EVENT_DISCONNECT,
    FIFO_EVENT_BUILTIN_RX,
    FIFO_EVENT_RPC,
  } fifo_event_type_t;
  
  static inline const char *
  fifo_event_type_str (fifo_event_type_t et)
  {
    switch (et)
      {
      case FIFO_EVENT_APP_RX:
        return "FIFO_EVENT_APP_RX";
      case FIFO_EVENT_APP_TX:
        return "FIFO_EVENT_APP_TX";
      case FIFO_EVENT_TIMEOUT:
        return "FIFO_EVENT_TIMEOUT";
      case FIFO_EVENT_DISCONNECT:
        return "FIFO_EVENT_DISCONNECT";
      case FIFO_EVENT_BUILTIN_RX:
        return "FIFO_EVENT_BUILTIN_RX";
      case FIFO_EVENT_RPC:
        return "FIFO_EVENT_RPC";
      default:
        return "UNKNOWN FIFO EVENT";
      }
  }
  
  #define foreach_session_input_error                                    	\
  _(NO_SESSION, "No session drops")                                       \
  _(NO_LISTENER, "No listener for dst port drops")                        \
  _(ENQUEUED, "Packets pushed into rx fifo")                              \
  _(NOT_READY, "Session not ready packets")                               \
  _(FIFO_FULL, "Packets dropped for lack of rx fifo space")               \
  _(EVENT_FIFO_FULL, "Events not sent for lack of event fifo space")      \
  _(API_QUEUE_FULL, "Sessions not created for lack of API queue space")   \
  _(NEW_SEG_NO_SPACE, "Created segment, couldn't allocate a fifo pair")   \
  _(NO_SPACE, "Couldn't allocate a fifo pair")
  
  typedef enum
  {
  #define _(sym,str) SESSION_ERROR_##sym,
    foreach_session_input_error
  #undef _
      SESSION_N_ERROR,
  } session_error_t;
  
  typedef struct
  {
    void *fp;
    void *arg;
  } rpc_args_t;
  
  /* *INDENT-OFF* */
  typedef CLIB_PACKED (struct {
    union
      {
        svm_fifo_t * fifo;
        u64 session_handle;
        rpc_args_t rpc_args;
      };
    u8 event_type;
    u8 postponed;
  }) session_fifo_event_t;
  /* *INDENT-ON* */
  
  /* Forward definition */
  typedef struct _session_manager_main session_manager_main_t;
  
  typedef int
    (session_fifo_rx_fn) (vlib_main_t * vm, vlib_node_runtime_t * node,
  			session_manager_main_t * smm,
  			session_fifo_event_t * e0, stream_session_t * s0,
  			u32 thread_index, int *n_tx_pkts);
  
  extern session_fifo_rx_fn session_tx_fifo_peek_and_snd;
  extern session_fifo_rx_fn session_tx_fifo_dequeue_and_snd;
  
  u8 session_node_lookup_fifo_event (svm_fifo_t * f, session_fifo_event_t * e);
  
  struct _session_manager_main
  {
    /** Per worker thread session pools */
    stream_session_t **sessions;
  
    /** Per worker-thread count of threads peeking into the session pool */
    u32 *session_peekers;
  
    /** Per worker-thread rw peekers locks */
    clib_spinlock_t *peekers_readers_locks;
    clib_spinlock_t *peekers_write_locks;
  
    /** Pool of listen sessions. Same type as stream sessions to ease lookups */
    stream_session_t **listen_sessions;
  
    /** Per-proto, per-worker enqueue epoch counters */
    u32 *current_enqueue_epoch[TRANSPORT_N_PROTO];
  
    /** Per-proto, per-worker thread vector of sessions to enqueue */
    u32 **session_to_enqueue[TRANSPORT_N_PROTO];
  
    /** per-worker tx buffer free lists */
    u32 **tx_buffers;
  
    /** Per worker-thread vector of partially read events */
    session_fifo_event_t **free_event_vector;
  
    /** per-worker active event vectors */
    session_fifo_event_t **pending_event_vector;
  
    /** per-worker postponed disconnects */
    session_fifo_event_t **pending_disconnects;
  
    /** vpp fifo event queue */
    unix_shared_memory_queue_t **vpp_event_queues;
  
    /** Unique segment name counter */
    u32 unique_segment_name_counter;
  
    /** Per transport rx function that can either dequeue or peek */
    session_fifo_rx_fn **session_tx_fns;
  
    /** Per session type output nodes. Could optimize to group nodes by
     * fib but lookup would then require session type parsing in session node.
     * Trade memory for speed, for now */
    u32 *session_type_to_next;
  
    /** Session manager is enabled */
    u8 is_enabled;
  
    /** vpp fifo event queue configured length */
    u32 configured_event_queue_length;
  
    /*
     * Config parameters
     */
  
    /** session table size parameters */
    u32 configured_v4_session_table_buckets;
    u32 configured_v4_session_table_memory;
    u32 configured_v4_halfopen_table_buckets;
    u32 configured_v4_halfopen_table_memory;
    u32 configured_v6_session_table_buckets;
    u32 configured_v6_session_table_memory;
    u32 configured_v6_halfopen_table_buckets;
    u32 configured_v6_halfopen_table_memory;
  
    /** Transport table (preallocation) size parameters */
    u32 local_endpoints_table_memory;
    u32 local_endpoints_table_buckets;
  
    /** Preallocate session config parameter */
    u32 preallocated_sessions;
  
  #if SESSION_DBG
    /**
     * last event poll time by thread
     * Debug only. Will cause false cache-line sharing as-is
     */
    f64 *last_event_poll_by_thread;
  #endif
  
  };
  
  extern session_manager_main_t session_manager_main;
  extern vlib_node_registration_t session_queue_node;
  
  /*
   * Session manager function
   */
  always_inline session_manager_main_t *
  vnet_get_session_manager_main ()
  {
    return &session_manager_main;
  }
  
  always_inline u8
  stream_session_is_valid (u32 si, u8 thread_index)
  {
    stream_session_t *s;
    s = pool_elt_at_index (session_manager_main.sessions[thread_index], si);
    if (s->thread_index != thread_index || s->session_index != si
        /* || s->server_rx_fifo->master_session_index != si
           || s->server_tx_fifo->master_session_index != si
           || s->server_rx_fifo->master_thread_index != thread_index
           || s->server_tx_fifo->master_thread_index != thread_index */ )
      return 0;
    return 1;
  }
  
  stream_session_t *session_alloc (u32 thread_index);
  
  always_inline stream_session_t *
  session_get (u32 si, u32 thread_index)
  {
    ASSERT (stream_session_is_valid (si, thread_index));
    return pool_elt_at_index (session_manager_main.sessions[thread_index], si);
  }
  
  always_inline stream_session_t *
  session_get_if_valid (u64 si, u32 thread_index)
  {
    if (thread_index >= vec_len (session_manager_main.sessions))
      return 0;
  
    if (pool_is_free_index (session_manager_main.sessions[thread_index], si))
      return 0;
  
    ASSERT (stream_session_is_valid (si, thread_index));
    return pool_elt_at_index (session_manager_main.sessions[thread_index], si);
  }
  
  always_inline u64
  session_handle (stream_session_t * s)
  {
    return ((u64) s->thread_index << 32) | (u64) s->session_index;
  }
  
  always_inline u32
  session_index_from_handle (u64 handle)
  {
    return handle & 0xFFFFFFFF;
  }
  
  always_inline u32
  session_thread_from_handle (u64 handle)
  {
    return handle >> 32;
  }
  
  always_inline void
  session_parse_handle (u64 handle, u32 * index, u32 * thread_index)
  {
    *index = session_index_from_handle (handle);
    *thread_index = session_thread_from_handle (handle);
  }
  
  always_inline stream_session_t *
  session_get_from_handle (u64 handle)
  {
    session_manager_main_t *smm = &session_manager_main;
    return
      pool_elt_at_index (smm->sessions[session_thread_from_handle (handle)],
  		       session_index_from_handle (handle));
  }
  
  always_inline transport_proto_t
  session_get_transport_proto (stream_session_t * s)
  {
    return (s->session_type >> 1);
  }
  
  always_inline session_type_t
  session_type_from_proto_and_ip (transport_proto_t proto, u8 is_ip4)
  {
    return (proto << 1 | is_ip4);
  }
  
  /**
   * Acquires a lock that blocks a session pool from expanding.
   *
   * This is typically used for safely peeking into other threads'
   * pools in order to clone elements. Lock should be dropped as soon
   * as possible by calling @ref session_pool_remove_peeker.
   *
   * NOTE: Avoid using pool_elt_at_index while the lock is held because
   * it may lead to free elt bitmap expansion/contraction!
   */
  always_inline void
  session_pool_add_peeker (u32 thread_index)
  {
    session_manager_main_t *smm = &session_manager_main;
    if (thread_index == vlib_get_thread_index ())
      return;
    clib_spinlock_lock_if_init (&smm->peekers_readers_locks[thread_index]);
    smm->session_peekers[thread_index] += 1;
    if (smm->session_peekers[thread_index] == 1)
      clib_spinlock_lock_if_init (&smm->peekers_write_locks[thread_index]);
    clib_spinlock_unlock_if_init (&smm->peekers_readers_locks[thread_index]);
  }
  
  always_inline void
  session_pool_remove_peeker (u32 thread_index)
  {
    session_manager_main_t *smm = &session_manager_main;
    if (thread_index == vlib_get_thread_index ())
      return;
    ASSERT (session_manager_main.session_peekers[thread_index] > 0);
    clib_spinlock_lock_if_init (&smm->peekers_readers_locks[thread_index]);
    smm->session_peekers[thread_index] -= 1;
    if (smm->session_peekers[thread_index] == 0)
      clib_spinlock_unlock_if_init (&smm->peekers_write_locks[thread_index]);
    clib_spinlock_unlock_if_init (&smm->peekers_readers_locks[thread_index]);
  }
  
  /**
   * Get session from handle and 'lock' pool resize if not in same thread
   *
   * Caller should drop the peek 'lock' as soon as possible.
   */
  always_inline stream_session_t *
  session_get_from_handle_safe (u64 handle)
  {
    session_manager_main_t *smm = &session_manager_main;
    u32 thread_index = session_thread_from_handle (handle);
    if (thread_index == vlib_get_thread_index ())
      {
        return pool_elt_at_index (smm->sessions[thread_index],
  				session_index_from_handle (handle));
      }
    else
      {
        session_pool_add_peeker (thread_index);
        /* Don't use pool_elt_at index. See @ref session_pool_add_peeker */
        return smm->sessions[thread_index] + session_index_from_handle (handle);
      }
  }
  
  always_inline stream_session_t *
  stream_session_listener_get (u8 sst, u64 si)
  {
    return pool_elt_at_index (session_manager_main.listen_sessions[sst], si);
  }
  
  always_inline u32
  stream_session_get_index (stream_session_t * s)
  {
    if (s->session_state == SESSION_STATE_LISTENING)
      return s - session_manager_main.listen_sessions[s->session_type];
  
    return s - session_manager_main.sessions[s->thread_index];
  }
  
  always_inline u32
  stream_session_max_rx_enqueue (transport_connection_t * tc)
  {
    stream_session_t *s = session_get (tc->s_index, tc->thread_index);
    return svm_fifo_max_enqueue (s->server_rx_fifo);
  }
  
  always_inline u32
  stream_session_rx_fifo_size (transport_connection_t * tc)
  {
    stream_session_t *s = session_get (tc->s_index, tc->thread_index);
    return s->server_rx_fifo->nitems;
  }
  
  always_inline u32
  session_get_index (stream_session_t * s)
  {
    return (s - session_manager_main.sessions[s->thread_index]);
  }
  
  always_inline stream_session_t *
  session_clone_safe (u32 session_index, u32 thread_index)
  {
    stream_session_t *old_s, *new_s;
    u32 current_thread_index = vlib_get_thread_index ();
  
    /* If during the memcpy pool is reallocated AND the memory allocator
     * decides to give the old chunk of memory to somebody in a hurry to
     * scribble something on it, we have a problem. So add this thread as
     * a session pool peeker.
     */
    session_pool_add_peeker (thread_index);
    new_s = session_alloc (current_thread_index);
    old_s = session_manager_main.sessions[thread_index] + session_index;
    clib_memcpy (new_s, old_s, sizeof (*new_s));
    session_pool_remove_peeker (thread_index);
    new_s->thread_index = current_thread_index;
    new_s->session_index = session_get_index (new_s);
    return new_s;
  }
  
  transport_connection_t *session_get_transport (stream_session_t * s);
  
  u32 stream_session_tx_fifo_max_dequeue (transport_connection_t * tc);
  
  stream_session_t *session_alloc (u32 thread_index);
  int
  session_enqueue_stream_connection (transport_connection_t * tc,
  				   vlib_buffer_t * b, u32 offset,
  				   u8 queue_event, u8 is_in_order);
  int session_enqueue_dgram_connection (stream_session_t * s, vlib_buffer_t * b,
  				      u8 proto, u8 queue_event);
  int stream_session_peek_bytes (transport_connection_t * tc, u8 * buffer,
  			       u32 offset, u32 max_bytes);
  u32 stream_session_dequeue_drop (transport_connection_t * tc, u32 max_bytes);
  
  int session_stream_connect_notify (transport_connection_t * tc, u8 is_fail);
  int session_dgram_connect_notify (transport_connection_t * tc,
  				  u32 old_thread_index,
  				  stream_session_t ** new_session);
  void stream_session_init_fifos_pointers (transport_connection_t * tc,
  					 u32 rx_pointer, u32 tx_pointer);
  
  void stream_session_accept_notify (transport_connection_t * tc);
  void stream_session_disconnect_notify (transport_connection_t * tc);
  void stream_session_delete_notify (transport_connection_t * tc);
  void stream_session_reset_notify (transport_connection_t * tc);
  int stream_session_accept (transport_connection_t * tc, u32 listener_index,
  			   u8 notify);
  int session_open (u32 app_index, session_endpoint_t * tep, u32 opaque);
  int stream_session_listen (stream_session_t * s, session_endpoint_t * tep);
  int stream_session_stop_listen (stream_session_t * s);
  void stream_session_disconnect (stream_session_t * s);
  void stream_session_cleanup (stream_session_t * s);
  void session_send_session_evt_to_thread (u64 session_handle,
  					 fifo_event_type_t evt_type,
  					 u32 thread_index);
  
  u8 *format_stream_session (u8 * s, va_list * args);
  uword unformat_stream_session (unformat_input_t * input, va_list * args);
  uword unformat_transport_connection (unformat_input_t * input,
  				     va_list * args);
  
  void session_register_transport (transport_proto_t transport_proto,
  				 const transport_proto_vft_t * vft, u8 is_ip4,
  				 u32 output_node);
  
  clib_error_t *vnet_session_enable_disable (vlib_main_t * vm, u8 is_en);
  
  always_inline unix_shared_memory_queue_t *
  session_manager_get_vpp_event_queue (u32 thread_index)
  {
    return session_manager_main.vpp_event_queues[thread_index];
  }
  
  int session_manager_flush_enqueue_events (u8 proto, u32 thread_index);
  
  always_inline u64
  listen_session_get_handle (stream_session_t * s)
  {
    ASSERT (s->session_state == SESSION_STATE_LISTENING);
    return ((u64) s->session_type << 32) | s->session_index;
  }
  
  always_inline stream_session_t *
  listen_session_get_from_handle (u64 handle)
  {
    session_manager_main_t *smm = &session_manager_main;
    stream_session_t *s;
    u32 type, index;
    type = handle >> 32;
    index = handle & 0xFFFFFFFF;
  
    if (pool_is_free_index (smm->listen_sessions[type], index))
      return 0;
  
    s = pool_elt_at_index (smm->listen_sessions[type], index);
    ASSERT (s->session_state == SESSION_STATE_LISTENING);
    return s;
  }
  
  always_inline stream_session_t *
  listen_session_new (session_type_t type)
  {
    stream_session_t *s;
    pool_get_aligned (session_manager_main.listen_sessions[type], s,
  		    CLIB_CACHE_LINE_BYTES);
    memset (s, 0, sizeof (*s));
  
    s->session_type = type;
    s->session_state = SESSION_STATE_LISTENING;
    s->session_index = s - session_manager_main.listen_sessions[type];
  
    return s;
  }
  
  always_inline stream_session_t *
  listen_session_get (session_type_t type, u32 index)
  {
    return pool_elt_at_index (session_manager_main.listen_sessions[type],
  			    index);
  }
  
  always_inline void
  listen_session_del (stream_session_t * s)
  {
    pool_put (session_manager_main.listen_sessions[s->session_type], s);
  }
  
  transport_connection_t *listen_session_get_transport (stream_session_t * s);
  
  int
  listen_session_get_local_session_endpoint (stream_session_t * listener,
  					   session_endpoint_t * sep);
  
  always_inline stream_session_t *
  session_manager_get_listener (u8 session_type, u32 index)
  {
    return
      pool_elt_at_index (session_manager_main.listen_sessions[session_type],
  		       index);
  }
  
  /**
   * Set peek or dequeue function for given session type
   *
   * Reliable transport protocols will probably want to use a peek function
   */
  always_inline void
  session_manager_set_transport_rx_fn (session_type_t type, u8 is_peek)
  {
    session_manager_main.session_tx_fns[type] = (is_peek) ?
      session_tx_fifo_peek_and_snd : session_tx_fifo_dequeue_and_snd;
  }
  
  always_inline u8
  session_manager_is_enabled ()
  {
    return session_manager_main.is_enabled == 1;
  }
  
  #define session_cli_return_if_not_enabled()				\
  do {									\
      if (!session_manager_main.is_enabled)				\
        return clib_error_return(0, "session layer is not enabled");	\
  } while (0)
  
  void session_node_enable_disable (u8 is_en);
  
  #endif /* __included_session_h__ */
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  