policy: ignore nameservers when starting lookup thread (rh #1031763)

When generating connections at startup for active interfaces, the
generation code may not always be able to read DNS information for
the connection.  Thus, the device's IP4Config won't have any
nameservers and the device won't be considered for reverse-address
lookup.  However, since any device that gets this far is already
the "best" device and has the default route, and thus should be the
one used for reverse-address lookup.

Second, reorganize the code better handle dual-stack in the
future by checking the IP configs directly, instead of the
devices.  Since 'best4' and 'best6' may be different devices,
we want to operate on the IP configs, not devices, to handle
situations where the best IP4Config may not be suitable for
reverse lookup, but the best IP6Config is.

https://bugzilla.redhat.com/show_bug.cgi?id=1031763

1 files changed, 19 insertions, 22 deletions

diff --git a/src/nm-policy.c b/src/nm-policy.c
index fe21d40e51..677f8f9e9e 100644
--- a/src/nm-policy.c
+++ b/src/nm-policy.c
@@ -369,6 +369,8 @@ update_system_hostname (NMPolicy *policy, NMDevice *best4, NMDevice *best6)
 	NMPolicyPrivate *priv = NM_POLICY_GET_PRIVATE (policy);
 	char *configured_hostname = NULL;
 	const char *dhcp_hostname, *p;
+	NMIP4Config *ip4_config;
+	NMIP6Config *ip6_config;
 
 	g_return_if_fail (policy != NULL);
 
@@ -459,42 +461,37 @@ update_system_hostname (NMPolicy *policy, NMDevice *best4, NMDevice *best6)
 	/* No configured hostname, no automatically determined hostname, and no
 	 * bootup hostname. Start reverse DNS of the current IPv4 or IPv6 address.
 	 */
-	if (best4) {
-		NMIP4Config *ip4_config;
-		const NMPlatformIP4Address *addr4;
+	ip4_config = best4 ? nm_device_get_ip4_config (best4) : NULL;
+	ip6_config = best6 ? nm_device_get_ip6_config (best6) : NULL;
 
-		ip4_config = nm_device_get_ip4_config (best4);
-		if (   !ip4_config
-		    || (nm_ip4_config_get_num_nameservers (ip4_config) == 0)
-		    || (nm_ip4_config_get_num_addresses (ip4_config) == 0)) {
-			/* No valid IP4 config (!!); fall back to localhost.localdomain */
-			_set_hostname (policy, NULL, "no IPv4 config");
-			return;
-		}
+	if (   (!ip4_config || (nm_ip4_config_get_num_addresses (ip4_config) == 0))
+	    && (!ip6_config || (nm_ip6_config_get_num_addresses (ip6_config) == 0))) {
+		/* No valid IP config; fall back to localhost.localdomain */
+		_set_hostname (policy, NULL, "no IP config");
+		return;
+	}
+
+	if (ip4_config) {
+		const NMPlatformIP4Address *addr4;
 
 		addr4 = nm_ip4_config_get_address (ip4_config, 0);
 		g_assert (addr4); /* checked for > 1 address above */
 
 		priv->lookup_addr = g_inet_address_new_from_bytes ((guint8 *) &addr4->address,
 		                                                     G_SOCKET_FAMILY_IPV4);
-	} else {
-		NMIP6Config *ip6_config;
+	} else if (ip6_config) {
 		const NMPlatformIP6Address *addr6;
 
-		ip6_config = nm_device_get_ip6_config (best6);
-		if (   !ip6_config
-		    || (nm_ip6_config_get_num_nameservers (ip6_config) == 0)
-		    || (nm_ip6_config_get_num_addresses (ip6_config) == 0)) {
-			/* No valid IP6 config (!!); fall back to localhost.localdomain */
-			_set_hostname (policy, NULL, "no IPv6 config");
-			return;
-		}
-
 		addr6 = nm_ip6_config_get_address (ip6_config, 0);
 		g_assert (addr6); /* checked for > 1 address above */
 
 		priv->lookup_addr = g_inet_address_new_from_bytes ((guint8 *) &addr6->address,
 		                                                     G_SOCKET_FAMILY_IPV6);
+	} else {
+		/* Should never get here... */
+		g_warn_if_reached ();
+		_set_hostname (policy, NULL, "no IP config");
+		return;
 	}
 
 	priv->lookup_cancellable = g_cancellable_new ();