From 742341e1443d8162e44020101bf93d22b11ce549 Mon Sep 17 00:00:00 2001
From: Stephen Worley <sworley@nvidia.com>
Date: Thu, 8 Apr 2021 19:20:53 -0400
Subject: [PATCH] bgpd: add mpath label stack helper functions for dvni

Add some bgp_path_info helper functions for getting the correct l3vni
label, getting the vni from the label stack, and determinging if
the mpath is D-VNI based.

Signed-off-by: Stephen Worley <sworley@nvidia.com>
---
 bgpd/bgp_evpn.c  | 64 ++++++++++++++++++++++++++++++++++++++++++++++++
 bgpd/bgp_evpn.h  |  5 ++++
 bgpd/bgp_zebra.c | 10 +++-----
 3 files changed, 72 insertions(+), 7 deletions(-)

diff --git a/bgpd/bgp_evpn.c b/bgpd/bgp_evpn.c
index d8acbcd19a..5fdf021104 100644
--- a/bgpd/bgp_evpn.c
+++ b/bgpd/bgp_evpn.c
@@ -55,6 +55,7 @@
 #include "bgpd/bgp_vty.h"
 #include "bgpd/bgp_nht.h"
 #include "bgpd/bgp_trace.h"
+#include "bgpd/bgp_mpath.h"
 
 /*
  * Definitions and external declarations.
@@ -7178,3 +7179,66 @@ void bgp_evpn_handle_resolve_overlay_index_unset(struct hash_bucket *bucket,
 
 	bgp_evpn_remote_ip_hash_destroy(vpn);
 }
+
+/*
+ * Helper function for getting the correct label index for l3vni.
+ *
+ * Returns the label with the l3vni of the path's label stack.
+ *
+ * L3vni is always last label. Type5 will only
+ * have one label, Type2 will have two.
+ *
+ */
+mpls_label_t *bgp_evpn_path_info_labels_get_l3vni(mpls_label_t *labels,
+						  uint32_t num_labels)
+{
+	if (!labels)
+		return NULL;
+
+	if (!num_labels)
+		return NULL;
+
+	return &labels[num_labels - 1];
+}
+
+/*
+ * Returns the l3vni of the path converted from the label stack.
+ */
+vni_t bgp_evpn_path_info_get_l3vni(const struct bgp_path_info *pi)
+{
+	if (!pi->extra)
+		return 0;
+
+	return label2vni(bgp_evpn_path_info_labels_get_l3vni(
+		pi->extra->label, pi->extra->num_labels));
+}
+
+/*
+ * Returns true if the l3vni of any of this path doesn't match vrf's l3vni.
+ */
+static bool bgp_evpn_path_is_dvni(const struct bgp *bgp_vrf,
+				  const struct bgp_path_info *pi)
+{
+	vni_t vni = 0;
+
+	vni = bgp_evpn_path_info_get_l3vni(pi);
+
+	if ((vni > 0) && (vni != bgp_vrf->l3vni))
+		return true;
+
+	return false;
+}
+
+/*
+ * Returns true if the l3vni of any of the mpath's doesn't match vrf's l3vni.
+ */
+bool bgp_evpn_mpath_has_dvni(const struct bgp *bgp_vrf,
+			     struct bgp_path_info *mpinfo)
+{
+	for (; mpinfo; mpinfo = bgp_path_info_mpath_next(mpinfo)) {
+		if (bgp_evpn_path_is_dvni(bgp_vrf, mpinfo))
+			return true;
+	}
+
+	return false;
+}
diff --git a/bgpd/bgp_evpn.h b/bgpd/bgp_evpn.h
index 3c980eb1da..4f95b71b1d 100644
--- a/bgpd/bgp_evpn.h
+++ b/bgpd/bgp_evpn.h
@@ -208,5 +208,10 @@ bgp_evpn_handle_resolve_overlay_index_set(struct hash_bucket *bucket,
 extern void
 bgp_evpn_handle_resolve_overlay_index_unset(struct hash_bucket *bucket,
 					    void *arg);
+extern mpls_label_t *bgp_evpn_path_info_labels_get_l3vni(mpls_label_t *labels,
+							 uint32_t num_labels);
+extern vni_t bgp_evpn_path_info_get_l3vni(const struct bgp_path_info *pi);
+extern bool bgp_evpn_mpath_has_dvni(const struct bgp *bgp_vrf,
+				    struct bgp_path_info *mpinfo);
 
 #endif /* _QUAGGA_BGP_EVPN_H */
diff --git a/bgpd/bgp_zebra.c b/bgpd/bgp_zebra.c
index fc2df44ac6..c1b27688dd 100644
--- a/bgpd/bgp_zebra.c
+++ b/bgpd/bgp_zebra.c
@@ -1523,14 +1523,10 @@ void bgp_zebra_announce(struct bgp_dest *dest, const struct prefix *p,
 			enum lsp_types_t nh_label_type = ZEBRA_LSP_NONE;
 
 			if (is_evpn) {
-				/*
-				 * L3VNI is always last label. Type5 will only
-				 * have one label, Type2 will have two.
-				 */
-				nh_label = labels[num_labels - 1];
+				nh_label = *bgp_evpn_path_info_labels_get_l3vni(
+					labels, num_labels);
 				nh_label_type = ZEBRA_LSP_EVPN;
-
-			} else if (bgp_is_valid_label(&labels[0])) {
+			} else {
 				mpls_lse_decode(labels[0], &nh_label, &ttl,
 						&exp, &bos);
 			}
-- 
2.39.5