From 1fddcd0a9b05258475a8ad6e106f59887a989044 Mon Sep 17 00:00:00 2001
From: Karen Schoener <karen@volta.io>
Date: Wed, 27 May 2020 12:10:30 -0400
Subject: [PATCH] zebra: Every time zebra receives a ZEBRA_PW_SET, zebra should
 evaluate nh

Every time zebra receives a ZEBRA_PW_SET, zebra should call
zebra_evaluate_rnh.

This fixes a race condition where zebra sometimes fails to install a
pseudowire that is 'up', and has a reachable next hop.

Signed-off-by: Karen Schoener <karen@voltanet.io>
---
 zebra/zebra_pw.c  |  9 ++++++---
 zebra/zebra_rnh.c | 13 ++++++++++---
 zebra/zebra_rnh.h |  2 +-
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/zebra/zebra_pw.c b/zebra/zebra_pw.c
index 273843baa2..59d69e7a36 100644
--- a/zebra/zebra_pw.c
+++ b/zebra/zebra_pw.c
@@ -125,9 +125,12 @@ void zebra_pw_change(struct zebra_pw *pw, ifindex_t ifindex, int type, int af,
 	pw->flags = flags;
 	pw->data = *data;
 
-	if (zebra_pw_enabled(pw))
-		zebra_register_rnh_pseudowire(pw->vrf_id, pw);
-	else {
+	if (zebra_pw_enabled(pw)) {
+		bool nht_exists;
+		zebra_register_rnh_pseudowire(pw->vrf_id, pw, &nht_exists);
+		if (nht_exists)
+			zebra_pw_update(pw);
+	} else {
 		if (pw->protocol == ZEBRA_ROUTE_STATIC)
 			zebra_deregister_rnh_pseudowire(pw->vrf_id, pw);
 		zebra_pw_uninstall(pw);
diff --git a/zebra/zebra_rnh.c b/zebra/zebra_rnh.c
index ad2e00b1ec..1692a47f3e 100644
--- a/zebra/zebra_rnh.c
+++ b/zebra/zebra_rnh.c
@@ -343,25 +343,32 @@ static void addr2hostprefix(int af, const union g_addr *addr,
 	}
 }
 
-void zebra_register_rnh_pseudowire(vrf_id_t vrf_id, struct zebra_pw *pw)
+void zebra_register_rnh_pseudowire(vrf_id_t vrf_id, struct zebra_pw *pw,
+				   bool *nht_exists)
 {
 	struct prefix nh;
 	struct rnh *rnh;
 	bool exists;
 	struct zebra_vrf *zvrf;
 
+	*nht_exists = false;
+
 	zvrf = vrf_info_lookup(vrf_id);
 	if (!zvrf)
 		return;
 
 	addr2hostprefix(pw->af, &pw->nexthop, &nh);
 	rnh = zebra_add_rnh(&nh, vrf_id, RNH_NEXTHOP_TYPE, &exists);
-	if (rnh && !listnode_lookup(rnh->zebra_pseudowire_list, pw)) {
+	if (!rnh)
+		return;
+
+	if (!listnode_lookup(rnh->zebra_pseudowire_list, pw)) {
 		listnode_add(rnh->zebra_pseudowire_list, pw);
 		pw->rnh = rnh;
 		zebra_evaluate_rnh(zvrf, family2afi(pw->af), 1,
 				   RNH_NEXTHOP_TYPE, &nh);
-	}
+	} else
+		*nht_exists = true;
 }
 
 void zebra_deregister_rnh_pseudowire(vrf_id_t vrf_id, struct zebra_pw *pw)
diff --git a/zebra/zebra_rnh.h b/zebra/zebra_rnh.h
index f07e5bc791..e744504920 100644
--- a/zebra/zebra_rnh.h
+++ b/zebra/zebra_rnh.h
@@ -50,7 +50,7 @@ extern struct rnh *zebra_lookup_rnh(struct prefix *p, vrf_id_t vrfid,
 extern void zebra_free_rnh(struct rnh *rnh);
 extern void zebra_add_rnh_client(struct rnh *rnh, struct zserv *client,
 				 enum rnh_type type, vrf_id_t vrfid);
-extern void zebra_register_rnh_pseudowire(vrf_id_t, struct zebra_pw *);
+extern void zebra_register_rnh_pseudowire(vrf_id_t, struct zebra_pw *, bool *);
 extern void zebra_deregister_rnh_pseudowire(vrf_id_t, struct zebra_pw *);
 extern void zebra_remove_rnh_client(struct rnh *rnh, struct zserv *client,
 				    enum rnh_type type);