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>
diff --git a/src/vcl/vcl_event.c b/src/vcl/vcl_event.c
new file mode 100644
index 0000000..b706a93
--- /dev/null
+++ b/src/vcl/vcl_event.c
@@ -0,0 +1,267 @@
+/*
+ * Copyright (c) 2019 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.
+ */
+
+#include <vppinfra/fifo.h>
+#include <vppinfra/pool.h>
+#include <vppinfra/hash.h>
+#include <vnet/api_errno.h>
+
+#include <vcl/vcl_event.h>
+/**
+ * @file
+ * @brief VPP Communications Library (VCL) event handler.
+ *
+ * Definitions for generic event handling in VCL.
+ */
+
+int
+vce_generate_event (vce_event_thread_t *evt, u32 ev_idx)
+{
+ int elts, rv = 0;
+ vce_event_t *p;
+
+ pthread_mutex_lock (&(evt->generator_lock));
+
+ /* Check there is event data for this event */
+
+ clib_spinlock_lock (&(evt->events_lockp));
+ p = pool_elt_at_index (evt->vce_events, ev_idx);
+ ASSERT(p);
+
+ elts = (int) clib_fifo_free_elts (evt->event_index_fifo);
+ if (PREDICT_TRUE (elts))
+ {
+ /* Add event to queue */
+ clib_fifo_add1 (evt->event_index_fifo, ev_idx);
+ pthread_cond_signal (&(evt->generator_cond));
+ }
+ else
+ {
+ rv = VNET_API_ERROR_QUEUE_FULL;
+ }
+
+ clib_spinlock_unlock (&(evt->events_lockp));
+ pthread_mutex_unlock (&(evt->generator_lock));
+
+ return rv;
+}
+
+void
+vce_clear_event (vce_event_thread_t *evt, vce_event_t *ev)
+{
+ clib_spinlock_lock (&(evt->events_lockp));
+ pool_put (evt->vce_events, ev);
+ clib_spinlock_unlock (&(evt->events_lockp));
+}
+
+vce_event_t *
+vce_get_event_from_index(vce_event_thread_t *evt, u32 ev_idx)
+{
+ vce_event_t *ev;
+
+ clib_spinlock_lock (&(evt->events_lockp));
+ ev = pool_elt_at_index (evt->vce_events, ev_idx);
+ clib_spinlock_unlock (&(evt->events_lockp));
+
+ return ev;
+
+}
+
+vce_event_handler_reg_t *
+vce_register_handler (vce_event_thread_t *evt, vce_event_key_t *evk,
+ vce_event_callback_t cb)
+{
+ vce_event_handler_reg_t *handler;
+ vce_event_handler_reg_t *old_handler = 0;
+ uword *p;
+ u32 handler_index;
+ u64 adj_key;
+
+ /* TODO - multiple handler support. For now we can replace
+ * and re-instate, which is useful for event recycling */
+
+ adj_key = evk->as_u64 | (1LL << 63); //evk can be 0, which won't hash
+
+ clib_spinlock_lock (&evt->handlers_lockp);
+
+ p = hash_get (evt->handlers_index_by_event_key, adj_key);
+ if (p)
+ {
+ old_handler = pool_elt_at_index (evt->vce_event_handlers, p[0]);
+ /* If we are just re-registering, ignore and move on
+ * else store the old handler_fn for unregister to re-instate */
+ if (old_handler->handler_fn == cb)
+ {
+
+ clib_spinlock_unlock (&evt->handlers_lockp);
+
+ /* Signal event thread that a handler exists in case any
+ * recycled events requiring this handler are pending */
+ pthread_mutex_lock (&(evt->generator_lock));
+ pthread_cond_signal (&(evt->generator_cond));
+ pthread_mutex_unlock (&(evt->generator_lock));
+ return old_handler;
+ }
+ }
+
+ pool_get (evt->vce_event_handlers, handler);
+ handler_index = (u32) (handler - evt->vce_event_handlers);
+
+ handler->handler_fn = cb;
+ handler->replaced_handler_idx = (p) ? p[0] : ~0;
+
+ hash_set (evt->handlers_index_by_event_key, adj_key, handler_index);
+
+ pthread_cond_init (&(handler->handler_cond), NULL);
+ pthread_mutex_init (&(handler->handler_lock), NULL);
+
+ clib_spinlock_unlock (&evt->handlers_lockp);
+
+ /* Signal event thread that a new handler exists in case any
+ * recycled events requiring this handler are pending */
+ pthread_mutex_lock (&(evt->generator_lock));
+ pthread_cond_signal (&(evt->generator_cond));
+ pthread_mutex_unlock (&(evt->generator_lock));
+
+ return handler;
+}
+
+int
+vce_unregister_handler (vce_event_thread_t *evt, vce_event_t *ev)
+{
+ vce_event_handler_reg_t *handler;
+ uword *p;
+ u64 adj_key = ev->evk.as_u64 | (1LL << 63);
+ u8 generate_signal = 0;
+
+ clib_spinlock_lock (&evt->handlers_lockp);
+
+ p = hash_get (evt->handlers_index_by_event_key, adj_key);
+ if (!p)
+ {
+ clib_spinlock_unlock (&evt->handlers_lockp);
+
+ return VNET_API_ERROR_NO_SUCH_ENTRY;
+ }
+
+ handler = pool_elt_at_index (evt->vce_event_handlers, p[0]);
+
+ /* If this handler replaced another handler, re-instate it */
+ if (handler->replaced_handler_idx != ~0)
+ {
+ hash_set (evt->handlers_index_by_event_key, adj_key,
+ handler->replaced_handler_idx);
+ generate_signal = 1;
+ }
+ else
+ {
+ hash_unset (evt->handlers_index_by_event_key, adj_key);
+ }
+
+ pthread_mutex_destroy (&(handler->handler_lock));
+ pthread_cond_destroy (&(handler->handler_cond));
+ pool_put (evt->vce_event_handlers, handler);
+
+ clib_spinlock_unlock (&evt->handlers_lockp);
+
+ if (generate_signal)
+ {
+ /* Signal event thread that a new handler exists in case any
+ * recycled events requiring this handler are pending */
+ pthread_mutex_lock (&(evt->generator_lock));
+ pthread_cond_signal (&(evt->generator_cond));
+ pthread_mutex_unlock (&(evt->generator_lock));
+ }
+
+ return 0;
+}
+
+void *
+vce_event_thread_fn (void *arg)
+{
+ vce_event_thread_t *evt = (vce_event_thread_t *) arg;
+ vce_event_t *ev;
+ u32 ev_idx;
+ vce_event_handler_reg_t *handler;
+ uword *p;
+ u64 adj_key;
+
+ evt->recycle_event = 1; // Used for recycling events with no handlers
+
+
+ do
+ {
+ pthread_mutex_lock (&(evt->generator_lock));
+ while ( (clib_fifo_elts (evt->event_index_fifo) == 0) ||
+ evt->recycle_event)
+ {
+ evt->recycle_event = 0;
+ pthread_cond_wait (&(evt->generator_cond),
+ &(evt->generator_lock));
+ }
+
+ /* Remove event */
+ clib_spinlock_lock (&(evt->events_lockp));
+
+ clib_fifo_sub1 (evt->event_index_fifo, ev_idx);
+ ev = pool_elt_at_index (evt->vce_events, ev_idx);
+
+ clib_spinlock_unlock (&(evt->events_lockp));
+
+ ASSERT(ev);
+ adj_key = ev->evk.as_u64 | (1LL << 63);
+
+ clib_spinlock_lock (&evt->handlers_lockp);
+
+ p = hash_get (evt->handlers_index_by_event_key, adj_key);
+ if (!p)
+ {
+ /* If an event falls in the woods, and there is no handler to hear it,
+ * does it make any sound?
+ * I don't know either, so lets try recycling the event */
+ clib_fifo_add1 (evt->event_index_fifo, ev_idx);
+ evt->recycle_event = 1;
+ clib_spinlock_unlock (&evt->handlers_lockp);
+ goto unlock;
+ }
+ handler = pool_elt_at_index (evt->vce_event_handlers, p[0]);
+ handler->ev_idx = ev_idx;
+
+ clib_spinlock_unlock (&evt->handlers_lockp);
+
+ (handler->handler_fn)(handler);
+
+ unlock:
+ pthread_mutex_unlock (&(evt->generator_lock));
+ }
+ while (1);
+ return NULL;
+}
+
+int
+vce_start_event_thread (vce_event_thread_t *evt, u8 max_events)
+{
+ clib_fifo_validate (evt->event_index_fifo, max_events);
+ evt->handlers_index_by_event_key = hash_create (0, sizeof (uword));
+
+ pthread_cond_init (&(evt->generator_cond), NULL);
+ pthread_mutex_init (&(evt->generator_lock), NULL);
+
+ clib_spinlock_init (&(evt->events_lockp));
+ clib_spinlock_init (&(evt->handlers_lockp));
+
+ return pthread_create (&(evt->thread), NULL /* attr */ ,
+ vce_event_thread_fn, evt);
+}
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