From fec4ca191ef4e7d9576feba756f728b21819ec45 Mon Sep 17 00:00:00 2001
From: Don Slice <dslice@cumulusnetworks.com>
Date: Tue, 21 Aug 2018 18:03:00 +0000
Subject: [PATCH] zebra: if multiple connecteds, select loopback or vrf if
 present

Signed-off-by: Don Slice <dslice@cumulusnetworks.com>
---
 lib/if.c          |  8 ++++++++
 lib/if.h          |  1 +
 pimd/pim_iface.c  |  8 --------
 pimd/pim_iface.h  |  2 --
 pimd/pim_pim.c    |  4 ++--
 zebra/zebra_rib.c | 26 +++++++++++++++++++++++---
 6 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/lib/if.c b/lib/if.c
index 943436f356..2bf0c6e6b5 100644
--- a/lib/if.c
+++ b/lib/if.c
@@ -472,6 +472,14 @@ int if_is_vrf(struct interface *ifp)
 	return CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_VRF_LOOPBACK);
 }
 
+bool if_is_loopback_or_vrf(struct interface *ifp)
+{
+	if (if_is_loopback(ifp) || if_is_vrf(ifp))
+		return true;
+
+	return false;
+}
+
 /* Does this interface support broadcast ? */
 int if_is_broadcast(struct interface *ifp)
 {
diff --git a/lib/if.h b/lib/if.h
index 3a9c4af848..a861cf2d85 100644
--- a/lib/if.h
+++ b/lib/if.h
@@ -497,6 +497,7 @@ extern int if_is_operative(struct interface *);
 extern int if_is_no_ptm_operative(struct interface *);
 extern int if_is_loopback(struct interface *);
 extern int if_is_vrf(struct interface *ifp);
+extern bool if_is_loopback_or_vrf(struct interface *ifp);
 extern int if_is_broadcast(struct interface *);
 extern int if_is_pointopoint(struct interface *);
 extern int if_is_multicast(struct interface *);
diff --git a/pimd/pim_iface.c b/pimd/pim_iface.c
index e79e91d7df..72ccf3ab1e 100644
--- a/pimd/pim_iface.c
+++ b/pimd/pim_iface.c
@@ -1495,14 +1495,6 @@ int pim_if_connected_to_source(struct interface *ifp, struct in_addr src)
 	return 0;
 }
 
-bool pim_if_is_loopback(struct interface *ifp)
-{
-	if (if_is_loopback(ifp) || if_is_vrf(ifp))
-		return true;
-
-	return false;
-}
-
 bool pim_if_is_vrf_device(struct interface *ifp)
 {
 	if (if_is_vrf(ifp))
diff --git a/pimd/pim_iface.h b/pimd/pim_iface.h
index cf025cbd4a..02926a6973 100644
--- a/pimd/pim_iface.h
+++ b/pimd/pim_iface.h
@@ -207,8 +207,6 @@ void pim_if_create_pimreg(struct pim_instance *pim);
 int pim_if_connected_to_source(struct interface *ifp, struct in_addr src);
 int pim_update_source_set(struct interface *ifp, struct in_addr source);
 
-bool pim_if_is_loopback(struct interface *ifp);
-
 bool pim_if_is_vrf_device(struct interface *ifp);
 
 int pim_if_ifchannel_count(struct pim_interface *pim_ifp);
diff --git a/pimd/pim_pim.c b/pimd/pim_pim.c
index b103da2e1b..7113d5405e 100644
--- a/pimd/pim_pim.c
+++ b/pimd/pim_pim.c
@@ -655,7 +655,7 @@ static int pim_hello_send(struct interface *ifp, uint16_t holdtime)
 {
 	struct pim_interface *pim_ifp = ifp->info;
 
-	if (pim_if_is_loopback(ifp))
+	if (if_is_loopback_or_vrf(ifp))
 		return 0;
 
 	if (hello_send(ifp, holdtime)) {
@@ -757,7 +757,7 @@ void pim_hello_restart_triggered(struct interface *ifp)
 	/*
 	 * No need to ever start loopback or vrf device hello's
 	 */
-	if (pim_if_is_loopback(ifp))
+	if (if_is_loopback_or_vrf(ifp))
 		return;
 
 	/*
diff --git a/zebra/zebra_rib.c b/zebra/zebra_rib.c
index 99b83d5cd9..ab07549ec2 100644
--- a/zebra/zebra_rib.c
+++ b/zebra/zebra_rib.c
@@ -1501,17 +1501,37 @@ static struct route_entry *rib_choose_best(struct route_entry *current,
 
 	/* filter route selection in following order:
 	 * - connected beats other types
+	 * - if both connected, loopback or vrf wins
 	 * - lower distance beats higher
 	 * - lower metric beats higher for equal distance
 	 * - last, hence oldest, route wins tie break.
 	 */
 
-	/* Connected routes. Pick the last connected
+	/* Connected routes. Check to see if either are a vrf
+	 * or loopback interface.  If not, pick the last connected
 	 * route of the set of lowest metric connected routes.
 	 */
 	if (alternate->type == ZEBRA_ROUTE_CONNECT) {
-		if (current->type != ZEBRA_ROUTE_CONNECT
-		    || alternate->metric <= current->metric)
+		if (current->type != ZEBRA_ROUTE_CONNECT)
+			return alternate;
+
+		/* both are connected.  are either loop or vrf? */
+		struct nexthop *nexthop = NULL;
+
+		for (ALL_NEXTHOPS(alternate->ng, nexthop)) {
+			if (if_is_loopback_or_vrf(if_lookup_by_index(
+				    nexthop->ifindex, alternate->vrf_id)))
+				return alternate;
+		}
+
+		for (ALL_NEXTHOPS(current->ng, nexthop)) {
+			if (if_is_loopback_or_vrf(if_lookup_by_index(
+				    nexthop->ifindex, current->vrf_id)))
+				return current;
+		}
+
+		/* Neither are loop or vrf so pick best metric  */
+		if (alternate->metric <= current->metric)
 			return alternate;
 
 		return current;