utils: add union inaddr

It will be a useful idiom for IP address storage and correct conversion
of sockaddr* pointers.

daemon/worker.h

@@ -120,14 +120,8 @@ struct qr_task
 	worker_cb_t on_complete;
 	void *baton;
 	struct {
-		union {
-			struct sockaddr_in ip4;
-			struct sockaddr_in6 ip6;
-		} addr;
-		union {
-			struct sockaddr_in ip4;
-			struct sockaddr_in6 ip6;
-		} dst_addr;
+		union inaddr addr;
+		union inaddr dst_addr;
 		uv_handle_t *handle;
 	} source;
 	uint32_t refs;

lib/nsrep.h

@@ -78,11 +78,7 @@ struct kr_nsrep
 	unsigned reputation;             /**< NS reputation */
 	const knot_dname_t *name;        /**< NS name */
 	struct kr_context *ctx;          /**< Resolution context */
-	union {
-		struct sockaddr ip;
-		struct sockaddr_in ip4;
-		struct sockaddr_in6 ip6;
-	} addr[KR_NSREP_MAXADDR];        /**< NS address(es) */
+	union inaddr addr[KR_NSREP_MAXADDR];        /**< NS address(es) */
 };
 
 /** @internal Address bytes for given family. */

lib/utils.h

@@ -137,6 +137,13 @@ KR_EXPORT
 int kr_pkt_put(knot_pkt_t *pkt, const knot_dname_t *name, uint32_t ttl,
                uint16_t rclass, uint16_t rtype, const uint8_t *rdata, uint16_t rdlen);
 
+/** Simple storage for IPx address or AF_UNSPEC. */
+union inaddr {
+	struct sockaddr ip;
+	struct sockaddr_in ip4;
+	struct sockaddr_in6 ip6;
+};
+
 /** Address bytes for given family. */
 KR_EXPORT KR_PURE
 const char *kr_inaddr(const struct sockaddr *addr);