ttl 0 is not valid on the wire, so dont accept it.

diff --git a/sys/net/if_gre.c b/sys/net/if_gre.c
index 36e545b..95dfe50 100644 (file)
--- 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;
                }