dispatcher: flag 16 (1<<4) for destinations with host not having A/AAAA record

- use it for addresses that should not be resolved with an A/AAAA query
at startup (e.g., it is a NAPTR or SRV only record for that specific
hostname)
- such addresses will not match when using ds_is_from_list(...)
- GH #1743

src/modules/dispatcher/dispatch.c

@@ -424,11 +424,17 @@ ds_dest_t *pack_dest(str iuri, int flags, int priority, str *attrs)
 	/* Do a DNS-Lookup for the Host-Name: */
 	he = resolvehost(hn);
 	if(he == 0) {
-		LM_ERR("could not resolve %.*s\n", puri.host.len, puri.host.s);
-		goto err;
+		if(dp->flags & DS_NODNSARES_DST) {
+			dp->irmode |= DS_IRMODE_NOIPADDR;
+		} else {
+			LM_ERR("could not resolve %.*s (missing no-probing flag?!?)\n",
+					puri.host.len, puri.host.s);
+			goto err;
+		}
+	} else {
+		/* Store hostent in the dispatcher structure */
+		hostent2ip_addr(&dp->ip_address, he, 0);
 	}
-	/* Free the hostname */
-	hostent2ip_addr(&dp->ip_address, he, 0);
 
 	/* Copy the port out of the URI */
 	dp->port = puri.port_no;
@@ -2957,8 +2963,8 @@ int ds_is_addr_from_list(sip_msg_t *_m, int group, str *uri, int mode)
 
 
 	if(group == -1) {
-		rc = ds_is_addr_from_set_r(
-				_m, pipaddr, tport, tproto, _ds_list, mode, 1);
+		rc = ds_is_addr_from_set_r(_m, pipaddr, tport, tproto, _ds_list,
+				mode, 1);
 	} else {
 		list = ds_avl_find(_ds_list, group);
 		if(list) {

src/modules/dispatcher/dispatch.h

@@ -44,7 +44,8 @@
 #define DS_TRYING_DST		2  /*!< temporary trying destination */
 #define DS_DISABLED_DST		4  /*!< admin disabled destination */
 #define DS_PROBING_DST		8  /*!< checking destination */
-#define DS_STATES_ALL		15  /*!< all bits for the states of destination */
+#define DS_NODNSARES_DST	16 /*!< no DNS A/AAAA resolve for host in uri */
+#define DS_STATES_ALL		31 /*!< all bits for the states of destination */
 
 #define ds_skip_dst(flags)	((flags) & (DS_INACTIVE_DST|DS_DISABLED_DST))
 
@@ -68,6 +69,8 @@
 
 #define DS_XAVP_CTX_SKIP_CNT	1
 
+#define DS_IRMODE_NOIPADDR	1
+
 /* clang-format on */
 
 extern str ds_db_url;
@@ -185,16 +188,17 @@ typedef struct _ds_latency_stats {
 } ds_latency_stats_t;
 
 typedef struct _ds_dest {
-	str uri;
-	int flags;
-	int priority;
-	int dload;
-	ds_attrs_t attrs;
-	ds_latency_stats_t latency_stats;
-	struct socket_info * sock;
-	struct ip_addr ip_address; 	/*!< IP-Address of the entry */
-	unsigned short int port; 	/*!< Port of the URI */
-	unsigned short int proto; 	/*!< Protocol of the URI */
+	str uri;          /*!< address/uri */
+	int flags;        /*!< flags */
+	int priority;     /*!< priority */
+	int dload;        /*!< load */
+	ds_attrs_t attrs; /*!< the atttributes */
+	ds_latency_stats_t latency_stats; /*!< latency statistics */
+	int irmode;       /*!< internal runtime mode (flags) */
+	struct socket_info *sock; /*!< pointer to local socket */
+	struct ip_addr ip_address; 	/*!< IP of the address */
+	unsigned short int port; 	/*!< port of the URI */
+	unsigned short int proto; 	/*!< protocol of the URI */
 	int message_count;
 	struct _ds_dest *next;
 } ds_dest_t;