udp: refactor udp code

Change-Id: I44d5c9df7c49b8d4d5677c6d319033b2da3e6b80
Signed-off-by: Florin Coras <fcoras@cisco.com>
diff --git a/src/vnet/session/session.h b/src/vnet/session/session.h
index b1a03d2..bd854d4 100644
--- a/src/vnet/session/session.h
+++ b/src/vnet/session/session.h
@@ -105,7 +105,7 @@
       rpc_args_t rpc_args;
     };
   u8 event_type;
-  u16 event_id;
+  u8 postponed;
 }) session_fifo_event_t;
 /* *INDENT-ON* */
 
@@ -128,17 +128,21 @@
   /** 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[SESSION_N_TYPES];
 
-  /** Sparse vector to map dst port to stream server  */
-  u16 *stream_server_by_dst_port[SESSION_N_TYPES];
+  /** Per-proto, per-worker enqueue epoch counters */
+  u8 *current_enqueue_epoch[TRANSPORT_N_PROTO];
 
-  /** per-worker enqueue epoch counters */
-  u8 *current_enqueue_epoch;
-
-  /** Per-worker thread vector of sessions to enqueue */
-  u32 **session_indices_to_enqueue_by_thread;
+  /** 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;
@@ -149,6 +153,9 @@
   /** 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;
 
@@ -213,6 +220,8 @@
   return 1;
 }
 
+stream_session_t *session_alloc (u32 thread_index);
+
 always_inline stream_session_t *
 session_get (u32 si, u32 thread_index)
 {
@@ -221,7 +230,7 @@
 }
 
 always_inline stream_session_t *
-stream_session_get_if_valid (u64 si, u32 thread_index)
+session_get_if_valid (u64 si, u32 thread_index)
 {
   if (thread_index >= vec_len (session_manager_main.sessions))
     return 0;
@@ -234,7 +243,7 @@
 }
 
 always_inline u64
-stream_session_handle (stream_session_t * s)
+session_handle (stream_session_t * s)
 {
   return ((u64) s->thread_index << 32) | (u64) s->session_index;
 }
@@ -267,6 +276,66 @@
 		       session_index_from_handle (handle));
 }
 
+/**
+ * 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)
 {
@@ -296,17 +365,52 @@
   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
-stream_session_enqueue_data (transport_connection_t * tc, vlib_buffer_t * b,
-			     u32 offset, u8 queue_event, u8 is_in_order);
-int
-stream_session_peek_bytes (transport_connection_t * tc, u8 * buffer,
-			   u32 offset, u32 max_bytes);
+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 stream_session_connect_notify (transport_connection_t * tc, u8 is_fail);
+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);
 
@@ -314,12 +418,9 @@
 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
-stream_session_open (u32 app_index, session_endpoint_t * tep,
-		     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);
@@ -346,7 +447,7 @@
   return session_manager_main.vpp_event_queues[thread_index];
 }
 
-int session_manager_flush_enqueue_events (u32 thread_index);
+int session_manager_flush_enqueue_events (u8 proto, u32 thread_index);
 
 always_inline u64
 listen_session_get_handle (stream_session_t * s)
@@ -400,6 +501,8 @@
   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);