VCL async event handler

- provides async handling of events such as accept/connect

Change-Id: Id95947237ef16629371b3c99822059d423e2f918
Signed-off-by: Keith Burns (alagalah) <alagalah@gmail.com>

1 files changed, 154 insertions, 0 deletions

diff --git a/src/vcl/vcl_event.h b/src/vcl/vcl_event.h
new file mode 100644
index 00000000000..9380f73f77d
--- /dev/null
+++ b/src/vcl/vcl_event.h
@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2018 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this
+ * 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 VPP_VCL_EVENT_H
+#define VPP_VCL_EVENT_H
+
+/**
+ * @file
+ * @brief VPP Communications Library (VCL) event handler.
+ *
+ * Declarations for generic event handling in VCL.
+ */
+
+#include <vppinfra/types.h>
+#include <vppinfra/lock.h>
+#include <pthread.h>
+
+typedef union vce_event_key_
+{
+  struct {
+    u32 eid;
+    u32 session_index;
+  };
+  u64 as_u64;
+} vce_event_key_t;
+
+typedef struct vce_event_
+{
+  vce_event_key_t evk;
+  u32 refcnt;
+  void *data;
+} vce_event_t;
+
+typedef void (*vce_event_callback_t) (void *reg /*vce_event_handler_reg_t* */);
+
+typedef struct vce_event_handler_reg_
+{
+  vce_event_callback_t handler_fn;
+  pthread_mutex_t handler_lock;
+  pthread_cond_t handler_cond;
+  u32 ev_idx;
+  u32 replaced_handler_idx;
+} vce_event_handler_reg_t;
+
+typedef struct vce_event_thread_
+{
+  pthread_t thread;
+  pthread_mutex_t generator_lock;
+  pthread_cond_t generator_cond;
+  u32 *event_index_fifo;
+  u8 recycle_event;
+  clib_spinlock_t events_lockp;
+  vce_event_t *vce_events; //pool
+  clib_spinlock_t handlers_lockp;
+  vce_event_handler_reg_t *vce_event_handlers; //pool
+  uword *handlers_index_by_event_key; //hash
+} vce_event_thread_t;
+
+/**
+ * @brief vce_generate_event
+ * - used to trigger an event in the event thread so that registered
+ *   handlers are notified
+ *
+ * @param evt - vce_event_thread_t - event system state
+ * @param ev_idx - index to vce_event_thread_t vce_event pool
+ *
+ * @return success/failure rv
+ */
+int vce_generate_event (vce_event_thread_t *evt, u32 ev_idx);
+
+/**
+ * @brief vce_clear_event()
+ * - removes event from event_pool
+ *
+ * @param evt - vce_event_thread_t - event system state
+ * @param ev  - vce_event_t - event to remove
+ */
+void vce_clear_event (vce_event_thread_t *evt, vce_event_t *ev);
+
+/**
+ * @brief vce_get_event_from_index()
+ *
+ * @param evt - vce_event_thread_t - event system state
+ * @param ev_idx - index to vce_event_thread_t vce_event pool
+ *
+ * @return vce_event_t *
+ */
+vce_event_t * vce_get_event_from_index(vce_event_thread_t *evt, u32 ev_idx);
+
+/**
+ * @brief vce_register_handler
+ * - used by functions who need to be notified that an event has occurred
+ *   on a vce_event_key_t (i.e. event type (enum) and sessionID)
+ * - if a handler already exists, the index to the old handler is stored
+ *   inside the new handler for re-instatement on vce_unregister_handler()
+
+ * @param evt - vce_event_thread_t - event system state
+ * @param evk - vce_event_key_t current an eventID from enum in consumer and
+ * 		sessionID
+ * @param cb  - vce_event_callback_t function to handle event
+ * @return vce_handler_reg_t - the function that needs event notification
+ *   needs to block on a condvar mutex to reduce spin. That is in here.
+ */
+vce_event_handler_reg_t * vce_register_handler (vce_event_thread_t *evt,
+						vce_event_key_t *evk,
+						vce_event_callback_t cb);
+
+/**
+ * @brief vce_unregister_handler
+ * - used by functions to remove need to be notified that an event has occurred
+ *   on a vce_event_key_t (i.e. event type (enum) and sessionID)
+ * - if this handler replaced an existing one, re-instate it.
+ *
+ * @param evt - vce_event_thread_t - event system state
+ * @param ev  - vce_event_t - event to remove
+ * @return success/failure rv
+ */
+int vce_unregister_handler (vce_event_thread_t *evt, vce_event_t *ev);
+
+/**
+ * @brief vce_event_thread_fn
+ * - main event thread that waits on a generic condvar/mutex that a signal
+ *   has been generated.
+ *   - loops through all registered handlers for that vce_event_key_t
+ *   (event enum + sessionID)
+ *
+ * @param arg - cast to type of event defined in consuming program.
+ * @return
+ */
+extern void * vce_event_thread_fn (void *arg);
+
+/**
+ * @brief vce_start_event_thread
+ * - as name suggests. What is important is that vce_event_thread_t is allocated
+ * on the same heap as "everything else". ie use clib_mem_alloc.
+ * @param evt - vce_event_thread_t - event system state
+ * @param max_events - depth of event FIFO for max number of outstanding events.
+ * @return succes/failure
+ */
+int vce_start_event_thread (vce_event_thread_t *evt, u8 max_events);
+
+#endif //VPP_VCL_EVENT_H