[PATCH 4/5] dns: Use compile time defined DNS for listener

Drop use of hardcoded DNSs with listener and use ones defined in
compile time to fully work with systemd-resolved.
---
 src/shared/dns.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/src/shared/dns.c b/src/shared/dns.c
index 930234fc..8f806536 100644
--- a/src/shared/dns.c
+++ b/src/shared/dns.c
@@ -2336,11 +2336,20 @@ static int create_listener(struct dns_listener_data *ifdata,
 
 	index = connman_inet_ifindex("lo");
 	if (ifdata->index == index && !ifdata->lo_exclude) {
+#ifdef SYSTEMD_RESOLVED_DNS_BACKEND
+		if (((err & IPv6_FAILED) != IPv6_FAILED) ||
+					((err & IPv4_FAILED) != IPv4_FAILED))
+			__connman_resolvfile_append(index, NULL,
+								DNS_BACKEND_V4);
+#else
 		if ((err & IPv6_FAILED) != IPv6_FAILED)
-			__connman_resolvfile_append(index, NULL, "::1");
+			__connman_resolvfile_append(index, NULL,
+								DNS_BACKEND_V6);
 
 		if ((err & IPv4_FAILED) != IPv4_FAILED)
-			__connman_resolvfile_append(index, NULL, "127.0.0.1");
+			__connman_resolvfile_append(index, NULL,
+								DNS_BACKEND_V4);
+#endif
 	}
 
 	return 0;
@@ -2351,8 +2360,13 @@ static void destroy_listener(struct dns_listener_data *ifdata)
 	int index = connman_inet_ifindex("lo");
 
 	if (ifdata->index == index && !ifdata->lo_exclude) {
-		__connman_resolvfile_remove(index, NULL, "127.0.0.1");
-		__connman_resolvfile_remove(index, NULL, "::1");
+
+		__connman_resolvfile_remove(index, NULL, DNS_BACKEND_V4);
+
+// With internal DNS this is defined, with systemd-resolved it is not.
+#ifndef SYSTEMD_RESOLVED_DNS_BACKEND
+		__connman_resolvfile_remove(index, NULL, DNS_BACKEND_V6);
+#endif
 	}
 
 	for (GSList *list = request_list; list; list = list->next) {
-- 
2.47.3