[PATCH 1.4 backport] device: cleanup setting of ip-iface

[Dan Williams <dcbw redhat com>]

From: Thomas Haller <thaller redhat com>
Date: Mon, 26 Dec 2016 18:11:03 +0100

Move the updating/setting of the ip-ifindex/ip-iface to one place.

Properties should be for the most part immutable/read-only, and only
at particular places modified. That way, it's easier to track who
changes a property.

Also, add a logging line with "ip-ifname" prefix.

(cherry picked from commit 78017f1bdc300656bba2d45e079fd638d285e909)
---
 src/devices/nm-device.c | 99 +++++++++++++++++++++++++++++++++----------------
 1 file changed, 67 insertions(+), 32 deletions(-)

diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index 2676aac..e934766 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -742,39 +742,83 @@ void
 nm_device_set_ip_iface (NMDevice *self, const char *iface)
 {
        NMDevicePrivate *priv;
-       char *old_ip_iface;
+       int ifindex;
 
        g_return_if_fail (NM_IS_DEVICE (self));
 
        priv = NM_DEVICE_GET_PRIVATE (self);
-       if (!g_strcmp0 (iface, priv->ip_iface))
-               return;
+       if (nm_streq0 (iface, priv->ip_iface)) {
+               if (!iface)
+                       return;
+               ifindex = nm_platform_link_get_ifindex (NM_PLATFORM_GET, iface);
+               if (   ifindex <= 0
+                   || priv->ip_ifindex == ifindex)
+                       return;
 
-       old_ip_iface = priv->ip_iface;
-       priv->ip_ifindex = 0;
+               priv->ip_ifindex = ifindex;
+               _LOGD (LOGD_DEVICE, "ip-ifname: update ifindex for ifname '%s': %d", iface, priv->ip_ifindex);
+       } else {
+               g_free (priv->ip_iface);
+               priv->ip_iface = g_strdup (iface);
 
-       priv->ip_iface = g_strdup (iface);
-       if (priv->ip_iface) {
-               priv->ip_ifindex = nm_platform_link_get_ifindex (NM_PLATFORM_GET, priv->ip_iface);
-               if (priv->ip_ifindex > 0) {
-                       if (nm_platform_check_support_user_ipv6ll (NM_PLATFORM_GET))
-                               nm_platform_link_set_user_ipv6ll_enabled (NM_PLATFORM_GET, priv->ip_ifindex, 
TRUE);
-
-                       if (!nm_platform_link_is_up (NM_PLATFORM_GET, priv->ip_ifindex))
-                               nm_platform_link_set_up (NM_PLATFORM_GET, priv->ip_ifindex, NULL);
+               if (iface) {
+                       /* The @iface name is not in sync with the platform cache.
+                        * So, there is no point asking the platform cache to resolve
+                        * the ifindex. Instead, we can only hope that the interface
+                        * with this name still exists and we resolve the ifindex
+                        * anew.
+                        */
+                       priv->ip_ifindex = nm_platform_link_get_ifindex (NM_PLATFORM_GET, iface);
+                       if (priv->ip_ifindex > 0)
+                               _LOGD (LOGD_DEVICE, "ip-ifname: set ifname '%s', ifindex %d", iface, 
priv->ip_ifindex);
+                       else
+                               _LOGW (LOGD_DEVICE, "ip-ifname: set ifname '%s', unknown ifindex", iface);
                } else {
-                       /* Device IP interface must always be a kernel network interface */
-                       _LOGW (LOGD_PLATFORM, "failed to look up interface index");
+                       priv->ip_ifindex = 0;
+                       _LOGD (LOGD_DEVICE, "ip-ifname: clear ifname");
                }
        }
 
+       if (priv->ip_ifindex > 0) {
+               if (nm_platform_check_support_user_ipv6ll (NM_PLATFORM_GET))
+                       nm_platform_link_set_user_ipv6ll_enabled (NM_PLATFORM_GET, priv->ip_ifindex, TRUE);
+
+               if (!nm_platform_link_is_up (NM_PLATFORM_GET, priv->ip_ifindex))
+                       nm_platform_link_set_up (NM_PLATFORM_GET, priv->ip_ifindex, NULL);
+       }
+
        /* We don't care about any saved values from the old iface */
        g_hash_table_remove_all (priv->ip6_saved_properties);
 
-       /* Emit change notification */
-       if (g_strcmp0 (old_ip_iface, priv->ip_iface))
-               _notify (self, PROP_IP_IFACE);
-       g_free (old_ip_iface);
+       _notify (self, PROP_IP_IFACE);
+}
+
+static gboolean
+_ip_iface_update (NMDevice *self, const char *ip_iface)
+{
+       NMDevicePrivate *priv;
+
+       g_return_val_if_fail (NM_IS_DEVICE (self), FALSE);
+
+       priv = NM_DEVICE_GET_PRIVATE (self);
+
+       g_return_val_if_fail (priv->ip_iface, FALSE);
+       g_return_val_if_fail (priv->ip_ifindex > 0, FALSE);
+       g_return_val_if_fail (ip_iface, FALSE);
+
+       if (!ip_iface[0])
+               return FALSE;
+
+       if (nm_streq (priv->ip_iface, ip_iface))
+               return FALSE;
+
+       _LOGI (LOGD_DEVICE, "ip-ifname: interface index %d renamed ip_iface (%d) from '%s' to '%s'",
+              priv->ifindex, priv->ip_ifindex,
+              priv->ip_iface, ip_iface);
+       g_free (priv->ip_iface);
+       priv->ip_iface = g_strdup (ip_iface);
+       _notify (self, PROP_IP_IFACE);
+       return TRUE;
 }
 
 /*****************************************************************************/
@@ -1953,16 +1997,8 @@ device_ip_link_changed (NMDevice *self)
 
        _stats_update_counters_from_pllink (self, pllink);
 
-       if (pllink->name[0] && g_strcmp0 (priv->ip_iface, pllink->name)) {
-               _LOGI (LOGD_DEVICE, "interface index %d renamed ip_iface (%d) from '%s' to '%s'",
-                      priv->ifindex, nm_device_get_ip_ifindex (self),
-                      priv->ip_iface, pllink->name);
-               g_free (priv->ip_iface);
-               priv->ip_iface = g_strdup (pllink->name);
-
-               _notify (self, PROP_IP_IFACE);
+       if (_ip_iface_update (self, pllink->name))
                nm_device_update_dynamic_ip_setup (self);
-       }
 
        return G_SOURCE_REMOVE;
 }
@@ -2465,10 +2501,9 @@ nm_device_unrealize (NMDevice *self, gboolean remove_resources, GError **error)
                _notify (self, PROP_IFINDEX);
        }
        priv->ip_ifindex = 0;
-       if (priv->ip_iface) {
-               g_clear_pointer (&priv->ip_iface, g_free);
+       if (nm_clear_g_free (&priv->ip_iface))
                _notify (self, PROP_IP_IFACE);
-       }
+
        if (priv->driver_version) {
                g_clear_pointer (&priv->driver_version, g_free);
                _notify (self, PROP_DRIVER_VERSION);
-- 
2.9.3