From 18c37974253c7406f4aab3a16c45b11e0be2f832 Mon Sep 17 00:00:00 2001
From: Mark Stapp <mjs@voltanet.io>
Date: Tue, 7 Aug 2018 16:00:33 -0400
Subject: [PATCH] zebra: add shutdown callback for dplane providers

Support fini or shutdown callback for dplane modules, to give
them an opportunity to cleanup.

Signed-off-by: Mark Stapp <mjs@voltanet.io>
---
 zebra/zebra_dplane.c | 30 +++++++++++++++++++++++++++---
 zebra/zebra_dplane.h |  6 +++++-
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/zebra/zebra_dplane.c b/zebra/zebra_dplane.c
index 7bc623fdf0..5e3aa6a4e9 100644
--- a/zebra/zebra_dplane.c
+++ b/zebra/zebra_dplane.c
@@ -18,6 +18,7 @@
  */
 
 #include "lib/zebra.h"
+#include "lib/libfrr.h"
 #include "lib/memory.h"
 #include "lib/frr_pthread.h"
 #include "lib/queue.h"
@@ -128,6 +129,8 @@ struct zebra_dplane_provider_s {
 
 	dplane_provider_process_fp dp_fp;
 
+	dplane_provider_fini_fp dp_fini;
+
 	/* Embedded list linkage */
 	TAILQ_ENTRY(zebra_dplane_provider_s) dp_q_providers;
 
@@ -728,7 +731,8 @@ static int dplane_route_process(struct thread *event)
  */
 int dplane_provider_register(const char *name,
 			     enum dplane_provider_prio_e prio,
-			     dplane_provider_process_fp fp)
+			     dplane_provider_process_fp fp,
+			     dplane_provider_fini_fp fini_fp)
 {
 	int ret = 0;
 	struct zebra_dplane_provider_s *p, *last;
@@ -753,10 +757,14 @@ int dplane_provider_register(const char *name,
 	}
 
 	strncpy(p->dp_name, name, DPLANE_PROVIDER_NAMELEN);
-	p->dp_name[DPLANE_PROVIDER_NAMELEN] = '\0';
+	p->dp_name[DPLANE_PROVIDER_NAMELEN] = '\0'; /* Belt-and-suspenders */
 
 	p->dp_priority = prio;
 	p->dp_fp = fp;
+	p->dp_fini = fini_fp;
+
+	/* Lock the lock - the dplane pthread may be running */
+	DPLANE_LOCK();
 
 	p->dp_id = ++zdplane_g.dg_provider_id;
 
@@ -771,6 +779,9 @@ int dplane_provider_register(const char *name,
 	else
 		TAILQ_INSERT_TAIL(&zdplane_g.dg_providers_q, p, dp_q_providers);
 
+	/* And unlock */
+	DPLANE_UNLOCK();
+
 done:
 	return ret;
 }
@@ -796,7 +807,7 @@ static void zebra_dplane_init_internal(struct zebra_t *zebra)
 	TAILQ_INIT(&zdplane_g.dg_route_ctx_q);
 	TAILQ_INIT(&zdplane_g.dg_providers_q);
 
-	/* TODO -- register kernel 'provider' during init */
+	/* TODO -- register default kernel 'provider' during init */
 
 	/* TODO -- start dataplane pthread. We're using the zebra
 	 * core/main thread temporarily
@@ -804,10 +815,23 @@ static void zebra_dplane_init_internal(struct zebra_t *zebra)
 	zdplane_g.dg_master = zebra->master;
 }
 
+/*
+ * Shutdown, de-init hook callback. This runs pretty early during shutdown.
+ */
+static int zebra_dplane_fini(void)
+{
+	/* TODO -- stop thread, clean queues */
+
+	return 0;
+}
+
 /*
  * Initialize the dataplane module at startup; called by zebra rib_init()
  */
 void zebra_dplane_init(void)
 {
 	zebra_dplane_init_internal(&zebrad);
+
+	/* Register for shutdown/de-init */
+	hook_register(frr_early_fini, zebra_dplane_fini);
 }
diff --git a/zebra/zebra_dplane.h b/zebra/zebra_dplane.h
index 2bcc85c36b..49c98879fe 100644
--- a/zebra/zebra_dplane.h
+++ b/zebra/zebra_dplane.h
@@ -200,10 +200,14 @@ enum dplane_provider_prio_e {
 /* Provider's entry-point to process a context block */
 typedef int (*dplane_provider_process_fp)(dplane_ctx_h ctx);
 
+/* Provider's entry-point for shutdown and cleanup */
+typedef int (*dplane_provider_fini_fp)(void);
+
 /* Provider registration */
 int dplane_provider_register(const char *name,
 			     enum dplane_provider_prio_e prio,
-			     dplane_provider_process_fp fp);
+			     dplane_provider_process_fp fp,
+			     dplane_provider_fini_fp fini_fp);
 
 /*
  * Results are returned to zebra core via a callback
-- 
2.39.5