Add grease controls to the view structure

lib/dns/include/dns/message.h

@@ -99,7 +99,8 @@
 #define DNS_MESSAGEFLAG_CD 0x0010U
 
 /*%< EDNS0 extended message flags */
-#define DNS_MESSAGEEXTFLAG_DO 0x8000U
+#define DNS_MESSAGEEXTFLAG_DO	       0x8000U
+#define DNS_MESSAGEEXTFLAG_KNOWN_FLAGS DNS_MESSAGEEXTFLAG_DO
 
 /*%< EDNS0 extended OPT codes */
 

lib/dns/include/dns/view.h

@@ -186,6 +186,20 @@ struct dns_view {
 	uint16_t	      max_queries;
 	uint8_t		      max_restarts;
 
+	/*
+	 * Grease the protocol by sending possible future
+	 * changes and checking the result matches defined
+	 * behaviour.
+	 */
+	bool	     grease_dns_flags;	      /* DNS flag 0x40 */
+	bool	     grease_edns_flags;	      /* EDNS Unknown flags */
+	bool	     grease_edns_neg;	      /* EDNS version negotiation */
+	bool	     grease_nsid;	      /* Request NSID */
+	uint8_t	     grease_edns_max_version; /* Currently 0 */
+	uint16_t     grease_edns_known_flags; /* Don't grease these flags */
+	unsigned int grease_rate;	      /* Grease this % of queries */
+	time_t	     grease_until; /* Turn off flags greasing at this time */
+
 	/*
 	 * Configurable data for server use only,
 	 * locked by server configuration lock.

lib/dns/view.c

@@ -120,6 +120,7 @@ dns_view_create(isc_mem_t *mctx, isc_loopmgr_t *loopmgr,
 		.root_key_sentinel = true,
 		.udpsize = DEFAULT_EDNS_BUFSIZE,
 		.max_restarts = DEFAULT_MAX_RESTARTS,
+		.grease_edns_known_flags = DNS_MESSAGEEXTFLAG_KNOWN_FLAGS,
 	};
 
 	isc_refcount_init(&view->references, 1);