From: Lennart Poettering <lennart@poettering.net>
Date: Thu, 26 Nov 2015 23:23:32 +0000 (+0100)
Subject: resolved: flush the global DNS cache if /etc/resolv.conf is touched
X-Git-Tag: v229~264^2~2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=452b4e327d23b9e468d3198f4c91e8efd0b52a71;p=thirdparty%2Fsystemd.git

resolved: flush the global DNS cache if /etc/resolv.conf is touched

After all /etc/resolv.conf is usually done when the network
configuration changes, which is a good reason to flush the global cache.

See: #2038
---

diff --git a/src/resolve/resolved-resolv-conf.c b/src/resolve/resolved-resolv-conf.c
index 63bde1c2f41..956f380f3c8 100644
--- a/src/resolve/resolved-resolv-conf.c
+++ b/src/resolve/resolved-resolv-conf.c
@@ -129,6 +129,15 @@ int manager_read_resolv_conf(Manager *m) {
          * resolve VPN domains. */
         manager_set_dns_server(m, m->dns_servers);
 
+        /* Unconditionally flush the cache when /etc/resolv.conf is
+         * modified, even if the data it contained was completely
+         * identical to the previous version we used. We do this
+         * because altering /etc/resolv.conf is typically done when
+         * the network configuration changes, and that should be
+         * enough to flush the global unicast DNS cache. */
+        if (m->unicast_scope)
+                dns_cache_flush(&m->unicast_scope->cache);
+
         return 0;
 
 clear: