From 611042a90f8f6991e32c7a7a394cbf63b82a3385 Mon Sep 17 00:00:00 2001
From: Naveen Thanikachalam <nthanikachal@vmware.com>
Date: Thu, 9 Apr 2020 00:27:54 -0700
Subject: [PATCH] bgpd: Enforce self-next-hop check in next-hop update.

When BGP receives a connected route from Zebra, it processes the
routes for the next-hop update.
While doing so, BGP must ignore routes whose next-hop address matches
the address of the connected route for which Zebra sent the next-hop update
message.

Signed-off-by: NaveenThanikachalam <nthanikachal@vmware.com>
---
 bgpd/bgp_nht.c   | 12 ++++++++++--
 bgpd/bgp_route.c |  6 +++---
 bgpd/bgp_route.h |  3 +++
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/bgpd/bgp_nht.c b/bgpd/bgp_nht.c
index 0531542a38f0..6ed2b63b51f4 100644
--- a/bgpd/bgp_nht.c
+++ b/bgpd/bgp_nht.c
@@ -745,8 +745,16 @@ static void evaluate_paths(struct bgp_nexthop_cache *bnc)
 			bnc_is_valid_nexthop =
 				bgp_isvalid_labeled_nexthop(bnc) ? 1 : 0;
 		} else {
-			bnc_is_valid_nexthop =
-				bgp_isvalid_nexthop(bnc) ? 1 : 0;
+			if (bgp_update_martian_nexthop(
+				    bnc->bgp, afi, safi, path->type,
+				    path->sub_type, path->attr, rn)) {
+				zlog_debug(
+					"Prefix %pRN, ignoring path due to martian or self-next-hop",
+					rn);
+			} else {
+				bnc_is_valid_nexthop =
+					bgp_isvalid_nexthop(bnc) ? 1 : 0;
+			}
 		}
 
 		if (BGP_DEBUG(nht, NHT))
diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index a11e1d7c693c..95b18f4e6dbb 100644
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -3226,9 +3226,9 @@ static bool overlay_index_equal(afi_t afi, struct bgp_path_info *path,
 }
 
 /* Check if received nexthop is valid or not. */
-static bool bgp_update_martian_nexthop(struct bgp *bgp, afi_t afi, safi_t safi,
-				       uint8_t type, uint8_t stype,
-				       struct attr *attr, struct bgp_node *rn)
+bool bgp_update_martian_nexthop(struct bgp *bgp, afi_t afi, safi_t safi,
+				uint8_t type, uint8_t stype, struct attr *attr,
+				struct bgp_node *rn)
 {
 	bool ret = 0;
 
diff --git a/bgpd/bgp_route.h b/bgpd/bgp_route.h
index ad08bbf44024..7532dc123aec 100644
--- a/bgpd/bgp_route.h
+++ b/bgpd/bgp_route.h
@@ -677,4 +677,7 @@ extern int bgp_show_table_rd(struct vty *vty, struct bgp *bgp, safi_t safi,
 			     enum bgp_show_type type, void *output_arg,
 			     bool use_json);
 extern int bgp_best_path_select_defer(struct bgp *bgp, afi_t afi, safi_t safi);
+extern bool bgp_update_martian_nexthop(struct bgp *bgp, afi_t afi, safi_t safi,
+				       uint8_t type, uint8_t stype,
+				       struct attr *attr, struct bgp_node *rn);
 #endif /* _QUAGGA_BGP_ROUTE_H */