isisd: Add overload timer and overload on startup functionality

Signed-off-by: Isabella de Leon <ideleon@microsoft.com>

4 files changed, 31 insertions, 2 deletions

diff --git a/isisd/isis_lsp.c b/isisd/isis_lsp.c
index 5387f3703..fbf559713 100644
--- a/isisd/isis_lsp.c
+++ b/isisd/isis_lsp.c
@@ -68,6 +68,8 @@ static void lsp_l2_refresh_pseudo(struct thread *thread);
 
 static void lsp_destroy(struct isis_lsp *lsp);
 
+static bool device_startup;
+
 int lsp_id_cmp(uint8_t *id1, uint8_t *id2)
 {
 	return memcmp(id1, id2, ISIS_SYS_ID_LEN + 2);
@@ -437,6 +439,18 @@ bool isis_level2_adj_up(struct isis_area *area)
 	return false;
 }
 
+/*
+ * Unset the overload bit after the timer expires
+ */
+void set_overload_on_start_timer(struct thread *thread)
+{
+	struct isis_area *area = THREAD_ARG(thread);
+	assert(area);
+
+	area->t_overload_on_startup_timer = NULL;
+	isis_area_overload_bit_set(area, false);
+}
+
 static void isis_reset_attach_bit(struct isis_adjacency *adj)
 {
 	struct isis_area *area = adj->circuit->area;
@@ -1431,6 +1445,20 @@ static int lsp_regenerate(struct isis_area *area, int level)
 	if ((area == NULL) || (area->is_type & level) != level)
 		return ISIS_ERROR;
 
+	/*
+	 * Check if the device is initializing and set overload bit on startup
+	 * is configured.
+	 */
+	if (device_startup) {
+		if (area->overload_on_startup_time > 0) {
+			isis_area_overload_bit_set(area, true);
+			thread_add_timer(master, set_overload_on_start_timer,
+					 area, area->overload_on_startup_time,
+					 &area->t_overload_on_startup_timer);
+		}
+		device_startup = false;
+	}
+
 	head = &area->lspdb[level - 1];
 	memset(lspid, 0, ISIS_SYS_ID_LEN + 2);
 	memcpy(lspid, area->isis->sysid, ISIS_SYS_ID_LEN);
@@ -2373,6 +2401,7 @@ int isis_lsp_iterate_is_reach(struct isis_lsp *lsp, uint16_t mtid,
 
 void lsp_init(void)
 {
+	device_startup = true;
 	hook_register(isis_adj_state_change_hook,
 		      lsp_handle_adj_state_change);
 }
diff --git a/isisd/isis_lsp.h b/isisd/isis_lsp.h
index b13b2a35e..d7762324d 100644
--- a/isisd/isis_lsp.h
+++ b/isisd/isis_lsp.h
@@ -66,6 +66,7 @@ DECLARE_RBTREE_UNIQ(lspdb, struct isis_lsp, dbe, lspdb_compare);
 void lsp_db_init(struct lspdb_head *head);
 void lsp_db_fini(struct lspdb_head *head);
 void lsp_tick(struct thread *thread);
+void set_overload_on_start_timer(struct thread *thread);
 
 int lsp_generate(struct isis_area *area, int level);
 #define lsp_regenerate_schedule(area, level, all_pseudo) \
diff --git a/isisd/isisd.c b/isisd/isisd.c
index 7a631128a..3ba00e6bf 100644
--- a/isisd/isisd.c
+++ b/isisd/isisd.c
@@ -3210,8 +3210,6 @@ void isis_area_overload_on_startup_set(struct isis_area *area,
 {
 	if (area->overload_on_startup_time != startup_time)
 		area->overload_on_startup_time = startup_time;
-
-	// TODO: Implement overload on startup functionality
 }
 
 void isis_area_attached_bit_send_set(struct isis_area *area, bool attached_bit)
diff --git a/isisd/isisd.h b/isisd/isisd.h
index 316f979e1..f1f92b365 100644
--- a/isisd/isisd.h
+++ b/isisd/isisd.h
@@ -142,6 +142,7 @@ struct isis_area {
 	struct flags flags;
 	struct thread *t_tick; /* LSP walker */
 	struct thread *t_lsp_refresh[ISIS_LEVELS];
+	struct thread *t_overload_on_startup_timer;
 	struct timeval last_lsp_refresh_event[ISIS_LEVELS];
 	struct thread *t_rlfa_rib_update;
 	/* t_lsp_refresh is used in two ways: