diff --git a/src/vnet/ipsec/esp_encrypt.c b/src/vnet/ipsec/esp_encrypt.c
index 7f9b5ed..86f9094 100644
--- a/src/vnet/ipsec/esp_encrypt.c
+++ b/src/vnet/ipsec/esp_encrypt.c
@@ -182,9 +182,9 @@
 
   return !u8x16_is_all_zero (ext_hdr_types == u8x16_splat (nexthdr));
 #else
-  return ((nexthdr ^ IP_PROTOCOL_IP6_HOP_BY_HOP_OPTIONS) |
-	  (nexthdr ^ IP_PROTOCOL_IPV6_ROUTE) |
-	  ((nexthdr ^ IP_PROTOCOL_IPV6_FRAGMENTATION) != 0));
+  return (!(nexthdr ^ IP_PROTOCOL_IP6_HOP_BY_HOP_OPTIONS) ||
+	  !(nexthdr ^ IP_PROTOCOL_IPV6_ROUTE) ||
+	  !(nexthdr ^ IP_PROTOCOL_IPV6_FRAGMENTATION));
 #endif
 }