From b1ab2876fa8d02fbb84feafde8e321456409ec1a Mon Sep 17 00:00:00 2001
From: rgirada <rgirada@vmware.com>
Date: Thu, 9 May 2019 22:35:48 -0700
Subject: [PATCH] staticd: static route config should fail if gw configured as
 its local ip.

Fix:
Added a check in staticd upon receiving nexthop update from zebra such that
it will fail to resolve the nexthop if the connected address added as nexthop.

But still allowing to add to staticd database and appears in running config.
Throwing an warning massage to user if such misconfig issued.

Signed-off-by: Rajesh Girada <rgirada@vmware.com>
---
 staticd/static_vty.c   | 18 +++++++++++++++++-
 staticd/static_zebra.c | 25 +++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/staticd/static_vty.c b/staticd/static_vty.c
index 3a9e4e8fa4..f926e1d9cd 100644
--- a/staticd/static_vty.c
+++ b/staticd/static_vty.c
@@ -35,7 +35,6 @@
 #ifndef VTYSH_EXTRACT_PL
 #include "staticd/static_vty_clippy.c"
 #endif
-
 static struct static_vrf *static_vty_get_unknown_vrf(struct vty *vty,
 						     const char *vrf_name)
 {
@@ -479,6 +478,23 @@ static int static_route_leak(
 			return CMD_WARNING_CONFIG_FAILED;
 		}
 		gatep = &gate;
+
+		if (afi == AFI_IP && !negate) {
+			if (if_lookup_exact_address(&gatep->ipv4, AF_INET,
+							svrf->vrf->vrf_id))
+				if (vty)
+					vty_out(vty,
+						"%% Warning!! Local connected address is configured as Gateway IP(%s)\n",
+						gate_str);
+		} else if (afi == AFI_IP6 && !negate) {
+			if (if_lookup_exact_address(&gatep->ipv6, AF_INET6,
+							svrf->vrf->vrf_id))
+				if (vty)
+					vty_out(vty,
+						"%% Warning!! Local connected address is configured as Gateway IPv6(%s)\n",
+						gate_str);
+		}
+
 	}
 
 	if (gate_str == NULL && ifname == NULL)
diff --git a/staticd/static_zebra.c b/staticd/static_zebra.c
index 27605da63f..1965c2968e 100644
--- a/staticd/static_zebra.c
+++ b/staticd/static_zebra.c
@@ -200,6 +200,25 @@ struct static_nht_data {
 	uint8_t nh_num;
 };
 
+/* API to check whether the configured nexthop address is
+ * one of its local connected address or not.
+ */
+static bool
+static_nexthop_is_local(vrf_id_t vrfid, struct prefix *addr, int family)
+{
+	if (family == AF_INET) {
+		if (if_lookup_exact_address(&addr->u.prefix4,
+					AF_INET,
+					vrfid))
+			return true;
+	} else if (family == AF_INET6) {
+		if (if_lookup_exact_address(&addr->u.prefix6,
+					AF_INET6,
+					vrfid))
+			return true;
+	}
+	return false;
+}
 static int static_zebra_nexthop_update(ZAPI_CALLBACK_ARGS)
 {
 	struct static_nht_data *nhtd, lookup;
@@ -214,6 +233,12 @@ static int static_zebra_nexthop_update(ZAPI_CALLBACK_ARGS)
 	if (nhr.prefix.family == AF_INET6)
 		afi = AFI_IP6;
 
+	if (nhr.type == ZEBRA_ROUTE_CONNECT) {
+		if (static_nexthop_is_local(vrf_id, &nhr.prefix,
+					nhr.prefix.family))
+			nhr.nexthop_num = 0;
+	}
+
 	memset(&lookup, 0, sizeof(lookup));
 	lookup.nh = &nhr.prefix;
 	lookup.nh_vrf_id = vrf_id;
-- 
2.39.5