resolved: automatically forget all learnt DNS server information when the network configuration changes

When the network configuration changes we should relearn everything
there is to know about the configured DNS servers, because we might talk
to the same addresses, but there might be different servers behind them.

1 files changed, 30 insertions, 5 deletions

diff --git a/src/resolve/resolved-dns-server.c b/src/resolve/resolved-dns-server.c
index b3d37525f4..f0822d1f72 100644
--- a/src/resolve/resolved-dns-server.c
+++ b/src/resolve/resolved-dns-server.c
@@ -70,15 +70,12 @@ int dns_server_new(
 
         s->n_ref = 1;
         s->manager = m;
-        s->verified_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID;
-        s->possible_feature_level = DNS_SERVER_FEATURE_LEVEL_BEST;
-        s->features_grace_period_usec = DNS_SERVER_FEATURE_GRACE_PERIOD_MIN_USEC;
-        s->received_udp_packet_max = DNS_PACKET_UNICAST_SIZE_MAX;
         s->type = type;
         s->family = family;
         s->address = *in_addr;
         s->ifindex = ifindex;
-        s->resend_timeout = DNS_TIMEOUT_MIN_USEC;
+
+        dns_server_reset_features(s);
 
         switch (type) {
 
@@ -828,6 +825,34 @@ void dns_server_flush_cache(DnsServer *s) {
         dns_cache_flush(&scope->cache);
 }
 
+void dns_server_reset_features(DnsServer *s) {
+        assert(s);
+
+        s->max_rtt = 0;
+        s->resend_timeout = DNS_TIMEOUT_MIN_USEC;
+
+        s->verified_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID;
+        s->possible_feature_level = DNS_SERVER_FEATURE_LEVEL_BEST;
+
+        s->received_udp_packet_max = DNS_PACKET_UNICAST_SIZE_MAX;
+
+        s->packet_bad_opt = false;
+        s->packet_rrsig_missing = false;
+
+        s->features_grace_period_usec = DNS_SERVER_FEATURE_GRACE_PERIOD_MIN_USEC;
+
+        s->warned_downgrade = false;
+
+        dns_server_reset_counters(s);
+}
+
+void dns_server_reset_features_all(DnsServer *s) {
+        DnsServer *i;
+
+        LIST_FOREACH(servers, i, s)
+                dns_server_reset_features(i);
+}
+
 static const char* const dns_server_type_table[_DNS_SERVER_TYPE_MAX] = {
         [DNS_SERVER_SYSTEM] = "system",
         [DNS_SERVER_FALLBACK] = "fallback",