pimd: inherit MLAG DF role from the parent (*, G) entry

DF election is only run for (*,G) entries i.e. election is skipped
for (S,G) entries that are setup as a result of SPT switchover. (S,G)
entries inherit the DF role from the parent (*,G) entry. So the DF is
responsible for terminating all sources associated with a group.

Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>

3 files changed, 55 insertions, 0 deletions

diff --git a/pimd/pim_upstream.c b/pimd/pim_upstream.c
index 2d3a44b646..8f7e1741e7 100644
--- a/pimd/pim_upstream.c
+++ b/pimd/pim_upstream.c
@@ -194,6 +194,9 @@ struct pim_upstream *pim_upstream_del(struct pim_instance *pim,
 		zlog_debug("pim_upstream free vrf:%s %s flags 0x%x",
 			   pim->vrf->name, up->sg_str, up->flags);
 
+	if (pim_up_mlag_is_local(up))
+		pim_mlag_up_local_del(pim, up);
+
 	THREAD_OFF(up->t_ka_timer);
 	THREAD_OFF(up->t_rs_timer);
 	THREAD_OFF(up->t_msdp_reg_timer);
@@ -884,6 +887,18 @@ static struct pim_upstream *pim_upstream_new(struct pim_instance *pim,
 		}
 	}
 
+	/* If (S, G) inherit the MLAG_VXLAN from the parent
+	 * (*, G) entry.
+	 */
+	if ((up->sg.src.s_addr != INADDR_ANY) &&
+		up->parent &&
+		PIM_UPSTREAM_FLAG_TEST_MLAG_VXLAN(up->parent->flags)) {
+		PIM_UPSTREAM_FLAG_SET_MLAG_VXLAN(up->flags);
+		if (PIM_DEBUG_VXLAN)
+			zlog_debug("upstream %s inherited mlag vxlan flag from parent",
+					up->sg_str);
+	}
+
 	/* send the entry to the MLAG peer */
 	/* XXX - duplicate send is possible here if pim_rpf_update
 	 * successfully resolved the nexthop
diff --git a/pimd/pim_vxlan.c b/pimd/pim_vxlan.c
index f1f5c81c00..58d988e920 100644
--- a/pimd/pim_vxlan.c
+++ b/pimd/pim_vxlan.c
@@ -551,6 +551,37 @@ static void pim_vxlan_term_mr_oif_del(struct pim_vxlan_sg *vxlan_sg)
 	pim_ifchannel_local_membership_del(vxlan_sg->term_oif, &vxlan_sg->sg);
 }
 
+static void pim_vxlan_update_sg_entry_mlag(struct pim_instance *pim,
+		struct pim_upstream *up, bool inherit)
+{
+	bool is_df = true;
+
+	if (inherit && up->parent &&
+			PIM_UPSTREAM_FLAG_TEST_MLAG_VXLAN(up->parent->flags) &&
+			PIM_UPSTREAM_FLAG_TEST_MLAG_NON_DF(up->parent->flags))
+		is_df = false;
+
+	pim_mlag_up_df_role_update(pim, up, is_df, "inherit_xg_df");
+}
+
+/* We run MLAG DF election only on mroutes that have the termination
+ * device ipmr-lo in the immediate OIL. This is only (*, G) entries at the
+ * moment. For (S, G) entries that (with ipmr-lo in the inherited OIL) we
+ * inherit the DF role from the (*, G) entry.
+ */
+void pim_vxlan_inherit_mlag_flags(struct pim_instance *pim,
+		struct pim_upstream *up, bool inherit)
+{
+	struct listnode *listnode;
+	struct pim_upstream *child;
+
+	for (ALL_LIST_ELEMENTS_RO(up->sources, listnode,
+				child)) {
+		pim_vxlan_update_sg_entry_mlag(pim,
+				child, true /* inherit */);
+	}
+}
+
 static void pim_vxlan_term_mr_up_add(struct pim_vxlan_sg *vxlan_sg)
 {
 	struct pim_upstream *up;
@@ -577,7 +608,11 @@ static void pim_vxlan_term_mr_up_add(struct pim_vxlan_sg *vxlan_sg)
 	if (!up) {
 		zlog_warn("vxlan SG %s term mroute-up add failed",
 			vxlan_sg->sg_str);
+		return;
 	}
+
+	/* update existing SG entries with the parent's MLAG flag */
+	pim_vxlan_inherit_mlag_flags(vxlan_sg->pim, up, true /*enable*/);
 }
 
 static void pim_vxlan_term_mr_up_del(struct pim_vxlan_sg *vxlan_sg)
@@ -592,6 +627,9 @@ static void pim_vxlan_term_mr_up_del(struct pim_vxlan_sg *vxlan_sg)
 			vxlan_sg->sg_str);
 	vxlan_sg->up = NULL;
 	if (up->flags & PIM_UPSTREAM_FLAG_MASK_SRC_VXLAN_TERM) {
+		/* update SG entries that are inheriting from this XG entry */
+		pim_vxlan_inherit_mlag_flags(vxlan_sg->pim, up,
+				false /*enable*/);
 		/* clear out all the vxlan related flags */
 		up->flags &= ~(PIM_UPSTREAM_FLAG_MASK_SRC_VXLAN_TERM |
 			PIM_UPSTREAM_FLAG_MASK_MLAG_VXLAN);
diff --git a/pimd/pim_vxlan.h b/pimd/pim_vxlan.h
index 4495dca6d7..7adba2eee2 100644
--- a/pimd/pim_vxlan.h
+++ b/pimd/pim_vxlan.h
@@ -139,5 +139,7 @@ extern void pim_vxlan_mlag_update(bool enable, bool peer_state, uint32_t role,
 				struct interface *peerlink_rif,
 				struct in_addr *reg_addr);
 extern bool pim_vxlan_do_mlag_reg(void);
+extern void pim_vxlan_inherit_mlag_flags(struct pim_instance *pim,
+		struct pim_upstream *up, bool inherit);
 
 #endif /* PIM_VXLAN_H */