4 files changed, 63 insertions, 11 deletions

diff --git a/src/resolve/resolved-conf.c b/src/resolve/resolved-conf.c
index 7e3b613816..c11a8badd9 100644
--- a/src/resolve/resolved-conf.c
+++ b/src/resolve/resolved-conf.c
@@ -48,7 +48,7 @@ int manager_add_dns_server_by_string(Manager *m, DnsServerType type, const char
                  * manager_mark_dns_servers() and
                  * manager_flush_marked_dns_servers().
                  */
-                s->marked = false;
+                dns_server_move_back_and_unmark(s);
                 return 0;
         }
 
diff --git a/src/resolve/resolved-dns-server.c b/src/resolve/resolved-dns-server.c
index 371594c710..81301ab800 100644
--- a/src/resolve/resolved-dns-server.c
+++ b/src/resolve/resolved-dns-server.c
@@ -48,25 +48,34 @@ int dns_server_new(
                 return -ENOMEM;
 
         s->n_ref = 1;
+        s->manager = m;
         s->type = type;
         s->family = family;
         s->address = *in_addr;
         s->resend_timeout = DNS_TIMEOUT_MIN_USEC;
 
-        if (type == DNS_SERVER_LINK) {
+        switch (type) {
+
+        case DNS_SERVER_LINK:
+                s->link = l;
                 LIST_FIND_TAIL(servers, l->dns_servers, tail);
                 LIST_INSERT_AFTER(servers, l->dns_servers, tail, s);
-                s->link = l;
-        } else if (type == DNS_SERVER_SYSTEM) {
+                break;
+
+        case DNS_SERVER_SYSTEM:
                 LIST_FIND_TAIL(servers, m->dns_servers, tail);
                 LIST_INSERT_AFTER(servers, m->dns_servers, tail, s);
-        } else if (type == DNS_SERVER_FALLBACK) {
+                break;
+
+        case DNS_SERVER_FALLBACK:
                 LIST_FIND_TAIL(servers, m->fallback_dns_servers, tail);
                 LIST_INSERT_AFTER(servers, m->fallback_dns_servers, tail, s);
-        } else
+                break;
+
+        default:
                 assert_not_reached("Unknown server type");
+        }
 
-        s->manager = m;
         s->linked = true;
 
         /* A new DNS server that isn't fallback is added and the one
@@ -145,6 +154,48 @@ void dns_server_unlink(DnsServer *s) {
         dns_server_unref(s);
 }
 
+void dns_server_move_back_and_unmark(DnsServer *s) {
+        DnsServer *tail;
+
+        assert(s);
+
+        if (!s->marked)
+                return;
+
+        s->marked = false;
+
+        if (!s->linked || !s->servers_next)
+                return;
+
+        /* Move us to the end of the list, so that the order is
+         * strictly kept, if we are not at the end anyway. */
+
+        switch (s->type) {
+
+        case DNS_SERVER_LINK:
+                assert(s->link);
+                LIST_FIND_TAIL(servers, s, tail);
+                LIST_REMOVE(servers, s->link->dns_servers, s);
+                LIST_INSERT_AFTER(servers, s->link->dns_servers, tail, s);
+                break;
+
+        case DNS_SERVER_SYSTEM:
+                LIST_FIND_TAIL(servers, s, tail);
+                LIST_REMOVE(servers, s->manager->dns_servers, s);
+                LIST_INSERT_AFTER(servers, s->manager->dns_servers, tail, s);
+                break;
+
+        case DNS_SERVER_FALLBACK:
+                LIST_FIND_TAIL(servers, s, tail);
+                LIST_REMOVE(servers, s->manager->fallback_dns_servers, s);
+                LIST_INSERT_AFTER(servers, s->manager->fallback_dns_servers, tail, s);
+                break;
+
+        default:
+                assert_not_reached("Unknown server type");
+        }
+}
+
 void dns_server_packet_received(DnsServer *s, usec_t rtt) {
         assert(s);
 
diff --git a/src/resolve/resolved-dns-server.h b/src/resolve/resolved-dns-server.h
index 9fed8f74a2..0077456cbc 100644
--- a/src/resolve/resolved-dns-server.h
+++ b/src/resolve/resolved-dns-server.h
@@ -31,6 +31,7 @@ typedef enum DnsServerType {
         DNS_SERVER_LINK,
 } DnsServerType;
 
+#include "resolved-manager.h"
 #include "resolved-link.h"
 
 struct DnsServer {
@@ -39,7 +40,6 @@ struct DnsServer {
         unsigned n_ref;
 
         DnsServerType type;
-
         Link *link;
 
         int family;
@@ -57,9 +57,9 @@ struct DnsServer {
 
 int dns_server_new(
                 Manager *m,
-                DnsServer **s,
+                DnsServer **ret,
                 DnsServerType type,
-                Link *l,
+                Link *link,
                 int family,
                 const union in_addr_union *address);
 
@@ -67,6 +67,7 @@ DnsServer* dns_server_ref(DnsServer *s);
 DnsServer* dns_server_unref(DnsServer *s);
 
 void dns_server_unlink(DnsServer *s);
+void dns_server_move_back_and_unmark(DnsServer *s);
 
 void dns_server_packet_received(DnsServer *s, usec_t rtt);
 void dns_server_packet_lost(DnsServer *s, usec_t usec);
diff --git a/src/resolve/resolved-link.c b/src/resolve/resolved-link.c
index ef3db773fd..4931fc9d3b 100644
--- a/src/resolve/resolved-link.c
+++ b/src/resolve/resolved-link.c
@@ -174,7 +174,7 @@ static int link_update_dns_servers(Link *l) {
 
                 s = link_find_dns_server(l, family, &a);
                 if (s)
-                        s->marked = false;
+                        dns_server_move_back_and_unmark(s);
                 else {
                         r = dns_server_new(l->manager, NULL, DNS_SERVER_LINK, l, family, &a);
                         if (r < 0)