From be418160a7695ae2b003ec0e42418d8cbd29bb84 Mon Sep 17 00:00:00 2001
From: rgirada <rgirada@vmware.com>
Date: Tue, 20 Jul 2021 03:24:56 -0700
Subject: [PATCH] ospfd: OSPF hello packets not sent with configured hello
 timer

Description :
	ospf hello timer is not getting refelcted upon
	changing the hello interval.

Signed-off-by: Rajesh Girada <rgirada@vmware.com>
---
 ospfd/ospf_interface.c | 52 ++++++++++++++++++++++++++++++++++++++++++
 ospfd/ospf_interface.h |  3 ++-
 ospfd/ospf_vty.c       | 15 ++++++++++--
 3 files changed, 67 insertions(+), 3 deletions(-)

diff --git a/ospfd/ospf_interface.c b/ospfd/ospf_interface.c
index 029f929c11..e0e61a2664 100644
--- a/ospfd/ospf_interface.c
+++ b/ospfd/ospf_interface.c
@@ -1447,6 +1447,58 @@ static int ospf_ifp_destroy(struct interface *ifp)
 	return 0;
 }
 
+/* Resetting ospf hello timer */
+void ospf_reset_hello_timer(struct interface *ifp, struct in_addr addr,
+			    bool is_addr)
+{
+	struct route_node *rn;
+
+	if (is_addr) {
+		struct prefix p;
+		struct ospf_interface *oi = NULL;
+
+		p.u.prefix4 = addr;
+		p.family = AF_INET;
+
+		oi = ospf_if_table_lookup(ifp, &p);
+
+		if (oi) {
+			/* Send hello before restart the hello timer
+			 * to avoid session flaps in case of bigger
+			 * hello interval configurations.
+			 */
+			ospf_hello_send(oi);
+
+			/* Restart hello timer for this interface */
+			OSPF_ISM_TIMER_OFF(oi->t_hello);
+			OSPF_HELLO_TIMER_ON(oi);
+		}
+
+		return;
+	}
+
+	for (rn = route_top(IF_OIFS(ifp)); rn; rn = route_next(rn)) {
+		struct ospf_interface *oi = rn->info;
+
+		if (!oi)
+			continue;
+
+		/* If hello interval configured on this oi, don't restart. */
+		if (OSPF_IF_PARAM_CONFIGURED(oi->params, v_hello))
+			continue;
+
+		/* Send hello before restart the hello timer
+		 * to avoid session flaps in case of bigger
+		 * hello interval configurations.
+		 */
+		ospf_hello_send(oi);
+
+		/* Restart the hello timer. */
+		OSPF_ISM_TIMER_OFF(oi->t_hello);
+		OSPF_HELLO_TIMER_ON(oi);
+	}
+}
+
 void ospf_if_init(void)
 {
 	if_zapi_callbacks(ospf_ifp_create, ospf_ifp_up,
diff --git a/ospfd/ospf_interface.h b/ospfd/ospf_interface.h
index 4a21147246..7ba6a2b6d7 100644
--- a/ospfd/ospf_interface.h
+++ b/ospfd/ospf_interface.h
@@ -345,7 +345,8 @@ extern void ospf_if_set_multicast(struct ospf_interface *);
 extern void ospf_if_interface(struct interface *ifp);
 
 extern uint32_t ospf_if_count_area_params(struct interface *ifp);
-
+extern void ospf_reset_hello_timer(struct interface *ifp, struct in_addr addr,
+				   bool is_addr);
 DECLARE_HOOK(ospf_vl_add, (struct ospf_vl_data * vd), (vd));
 DECLARE_HOOK(ospf_vl_delete, (struct ospf_vl_data * vd), (vd));
 
diff --git a/ospfd/ospf_vty.c b/ospfd/ospf_vty.c
index 2cb3ec0894..a148a85628 100644
--- a/ospfd/ospf_vty.c
+++ b/ospfd/ospf_vty.c
@@ -8305,10 +8305,12 @@ DEFUN (ip_ospf_hello_interval,
 {
 	VTY_DECLVAR_CONTEXT(interface, ifp);
 	int idx = 0;
-	struct in_addr addr;
+	struct in_addr addr = {.s_addr = 0L};
 	struct ospf_if_params *params;
 	params = IF_DEF_PARAMS(ifp);
 	uint32_t seconds = 0;
+	bool is_addr = false;
+	uint32_t old_interval = 0;
 
 	argv_find(argv, argc, "(1-65535)", &idx);
 	seconds = strtol(argv[idx]->arg, NULL, 10);
@@ -8322,8 +8324,15 @@ DEFUN (ip_ospf_hello_interval,
 
 		params = ospf_get_if_params(ifp, addr);
 		ospf_if_update_params(ifp, addr);
+		is_addr = true;
 	}
 
+	old_interval = params->v_hello;
+
+	/* Return, if same interval is configured. */
+	if (old_interval == seconds)
+		return CMD_SUCCESS;
+
 	SET_IF_PARAM(params, v_hello);
 	params->v_hello = seconds;
 
@@ -8338,6 +8347,8 @@ DEFUN (ip_ospf_hello_interval,
 		params->v_wait	= 4 * seconds;
 	}
 
+	ospf_reset_hello_timer(ifp, addr, is_addr);
+
 	return CMD_SUCCESS;
 }
 
@@ -8364,7 +8375,7 @@ DEFUN (no_ip_ospf_hello_interval,
 {
 	VTY_DECLVAR_CONTEXT(interface, ifp);
 	int idx = 0;
-	struct in_addr addr;
+	struct in_addr addr = {.s_addr = 0L};
 	struct ospf_if_params *params;
 	struct route_node *rn;
 
-- 
2.39.5