vapi: add vapi_stop_rx_thread()

Type: improvement

Allow vapi to signal to an application's RX thread that it should wake
up and exit.

Before disconnecting from VPP's API, libvlibmemoryclient inserts an
rx_thread_exit message into the client's own input queue to cause its
RX thread to wake up from its blocking dequeue and exit cleanly. Add a
function to vapi's API which will allow libvapi client applications
which have an RX thread waiting for incoming messages using vapi_wait()
to do the same thing.

The existing libvlibmemoryclient code which does this was moved to a
separate function and made available for vapi_stop_rx_thread() to call.

Also fixed some inconsistencies in indentation of function prototypes in
vapi.h to make checkstyle.sh happy.

Signed-off-by: Matthew Smith <mgsmith@netgate.com>
Change-Id: I7bbb73470807123cc63ef313cfb91d1fd31b34e5

4 files changed, 47 insertions, 18 deletions

diff --git a/src/vlibmemory/memory_client.c b/src/vlibmemory/memory_client.c
index d2323de0034..c66c71c43b1 100644
--- a/src/vlibmemory/memory_client.c
+++ b/src/vlibmemory/memory_client.c
@@ -510,6 +510,14 @@ vl_client_connect_to_vlib_thread_fn (const char *svm_name,
 				   thread_fn, arg, 1 /* do map */ );
 }
 
+void
+vl_client_stop_rx_thread (svm_queue_t *vl_input_queue)
+{
+  vl_api_rx_thread_exit_t *ep;
+  ep = vl_msg_api_alloc (sizeof (*ep));
+  ep->_vl_msg_id = ntohs (VL_API_RX_THREAD_EXIT);
+  vl_msg_api_send_shmem (vl_input_queue, (u8 *) &ep);
+}
 
 static void
 disconnect_from_vlib_internal (u8 do_unmap)
@@ -520,10 +528,7 @@ disconnect_from_vlib_internal (u8 do_unmap)
 
   if (mm->rx_thread_jmpbuf_valid)
     {
-      vl_api_rx_thread_exit_t *ep;
-      ep = vl_msg_api_alloc (sizeof (*ep));
-      ep->_vl_msg_id = ntohs (VL_API_RX_THREAD_EXIT);
-      vl_msg_api_send_shmem (am->vl_input_queue, (u8 *) & ep);
+      vl_client_stop_rx_thread (am->vl_input_queue);
       pthread_join (mm->rx_thread_handle, (void **) &junk);
     }
   if (mm->connected_to_vlib)
diff --git a/src/vlibmemory/memory_client.h b/src/vlibmemory/memory_client.h
index 3b8f671415c..3b9b2d8d959 100644
--- a/src/vlibmemory/memory_client.h
+++ b/src/vlibmemory/memory_client.h
@@ -62,6 +62,7 @@ int vl_client_connect_to_vlib_no_rx_pthread_no_map (const char *svm_name,
 						    int rx_queue_size);
 void vl_client_install_client_message_handlers (void);
 u8 vl_mem_client_is_connected (void);
+void vl_client_stop_rx_thread (svm_queue_t *vl_input_queue);
 
 always_inline memory_client_main_t *
 vlibapi_get_memory_client_main (void)
diff --git a/src/vpp-api/vapi/vapi.c b/src/vpp-api/vapi/vapi.c
index 3bf56cf64cd..7700eb06d3a 100644
--- a/src/vpp-api/vapi/vapi.c
+++ b/src/vpp-api/vapi/vapi.c
@@ -1420,6 +1420,16 @@ vapi_get_msg_name (vapi_msg_id_t id)
   return __vapi_metadata.msgs[id]->name;
 }
 
+void
+vapi_stop_rx_thread (vapi_ctx_t ctx)
+{
+  if (!ctx || !ctx->connected || !ctx->vl_input_queue)
+    {
+      return;
+    }
+
+  vl_client_stop_rx_thread (ctx->vl_input_queue);
+}
 /*
  * fd.io coding-style-patch-verification: ON
  *
diff --git a/src/vpp-api/vapi/vapi.h b/src/vpp-api/vapi/vapi.h
index f4e060b0180..c131920a88f 100644
--- a/src/vpp-api/vapi/vapi.h
+++ b/src/vpp-api/vapi/vapi.h
@@ -208,7 +208,7 @@ vapi_error_e vapi_wait (vapi_ctx_t ctx);
  *
  * @return VAPI_OK on success, other error code on error
  */
-  vapi_error_e vapi_dispatch_one (vapi_ctx_t ctx);
+vapi_error_e vapi_dispatch_one (vapi_ctx_t ctx);
 
 /**
  * @brief loop vapi_dispatch_one until responses to all currently outstanding
@@ -224,11 +224,11 @@ vapi_error_e vapi_wait (vapi_ctx_t ctx);
  *
  * @return VAPI_OK on success, other error code on error
  */
-  vapi_error_e vapi_dispatch (vapi_ctx_t ctx);
+vapi_error_e vapi_dispatch (vapi_ctx_t ctx);
 
 /** generic vapi event callback */
-  typedef vapi_error_e (*vapi_event_cb) (vapi_ctx_t ctx, void *callback_ctx,
-					 void *payload);
+typedef vapi_error_e (*vapi_event_cb) (vapi_ctx_t ctx, void *callback_ctx,
+				       void *payload);
 
 /**
  * @brief set event callback to call when message with given id is dispatched
@@ -238,8 +238,8 @@ vapi_error_e vapi_wait (vapi_ctx_t ctx);
  * @param callback callback
  * @param callback_ctx context pointer stored and passed to callback
  */
-  void vapi_set_event_cb (vapi_ctx_t ctx, vapi_msg_id_t id,
-			  vapi_event_cb callback, void *callback_ctx);
+void vapi_set_event_cb (vapi_ctx_t ctx, vapi_msg_id_t id,
+			vapi_event_cb callback, void *callback_ctx);
 
 /**
  * @brief clear event callback for given message id
@@ -247,12 +247,12 @@ vapi_error_e vapi_wait (vapi_ctx_t ctx);
  * @param ctx opaque vapi context
  * @param id message id
  */
-  void vapi_clear_event_cb (vapi_ctx_t ctx, vapi_msg_id_t id);
+void vapi_clear_event_cb (vapi_ctx_t ctx, vapi_msg_id_t id);
 
 /** generic vapi event callback */
-  typedef vapi_error_e (*vapi_generic_event_cb) (vapi_ctx_t ctx,
-						 void *callback_ctx,
-						 vapi_msg_id_t id, void *msg);
+typedef vapi_error_e (*vapi_generic_event_cb) (vapi_ctx_t ctx,
+					       void *callback_ctx,
+					       vapi_msg_id_t id, void *msg);
 /**
  * @brief set generic event callback
  *
@@ -263,16 +263,29 @@ vapi_error_e vapi_wait (vapi_ctx_t ctx);
  * @param callback callback
  * @param callback_ctx context pointer stored and passed to callback
  */
-  void vapi_set_generic_event_cb (vapi_ctx_t ctx,
-				  vapi_generic_event_cb callback,
-				  void *callback_ctx);
+void vapi_set_generic_event_cb (vapi_ctx_t ctx, vapi_generic_event_cb callback,
+				void *callback_ctx);
 
 /**
  * @brief clear generic event callback
  *
  * @param ctx opaque vapi context
  */
-  void vapi_clear_generic_event_cb (vapi_ctx_t ctx);
+void vapi_clear_generic_event_cb (vapi_ctx_t ctx);
+
+/**
+ * @brief signal RX thread to exit
+ *
+ * @note This adds a message to the client input queue that indicates that
+ * an RX thread should stop processing incoming messages and exit. If an
+ * application has an RX thread which sleeps while waiting for incoming
+ * messages using vapi_wait(), this call will allow the application to
+ * wake up from the vapi_wait() call and figure out that it should stop
+ * running.
+ *
+ * @param ctx opaque vapi context
+ */
+void vapi_stop_rx_thread (vapi_ctx_t ctx);
 
 #ifdef __cplusplus
 }