From 2485fd1a70c9d2931bb681763258fcf7666632c1 Mon Sep 17 00:00:00 2001
From: dlg <dlg@openbsd.org>
Date: Thu, 8 Feb 2018 22:11:06 +0000
Subject: [PATCH] ttl 0 is not valid on the wire, so dont accept it.

---
 sys/net/if_gre.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sys/net/if_gre.c b/sys/net/if_gre.c
index 36e545b6a03..95dfe5056e7 100644
--- a/sys/net/if_gre.c
+++ b/sys/net/if_gre.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: if_gre.c,v 1.94 2018/02/08 22:08:18 dlg Exp $ */
+/*      $OpenBSD: if_gre.c,v 1.95 2018/02/08 22:11:06 dlg Exp $ */
 /*	$NetBSD: if_gre.c,v 1.9 1999/10/25 19:18:11 drochner Exp $ */
 
 /*
@@ -1056,7 +1056,7 @@ gre_tunnel_ioctl(struct ifnet *ifp, struct gre_tunnel *tunnel,
 		break;
 
 	case SIOCSLIFPHYTTL:
-		if (ifr->ifr_ttl < 0 || ifr->ifr_ttl > 0xff) {
+		if (ifr->ifr_ttl < 1 || ifr->ifr_ttl > 0xff) {
 			error = EINVAL;
 			break;
 		}
-- 
2.20.1