Re: Getting NM to re-try DHCP

[Jirka Klimes <jklimes redhat com>]

On Thursday 07 of April 2011 00:24:44 Dan Williams wrote:
> On Tue, 2011-04-05 at 11:37 -0400, Derek Atkins wrote:
> > Hey all,
> > 
> > I have a strange issue.  I lost power last night and one of my systems
> > came up before my DHCP server did (which is surprising, because my DHCP
> > server usually comes up pretty quick!)  This "client" system was
> > supposed to get itself on the network (it has an auto-logon system).
> > However, NM didn't succeed because my DHCP server wasn't responding,
> > yet.
> > 
> > This is a hard-wired system (not wireless).  Is there any way to get NM
> > to periodically retry DHCP if at first it does not succeed?
> > 
> > I realize that DHCP has its own retry mechanism, but if the whole
> > process times out, can I set NM to retry every, say, 5 minutes?
> 
> We'd need some code changes in NM; basically for wired connections if
> the activation attempt fails a certain number of times (currently 3)
> then the connection is marked "invalid".  What probably should happen is
> that internally, in nm-policy.c, a timeout handler should be scheduled
> for the connection (using g_timeout_add_seconds()) that triggers after 5
> minutes or so and if the connection isn't currently active (ie check the
> NMManager's active connection list) then the invalid flag is cleared
> from the connection, which will let it be automatically retried.
> 
> It's pretty simple from a code perspective, just hasn't been done yet in
> the run-up to 0.9 and 0.8.4.  Any takers?
> 
> Dan

A patch doing that is in the attachment.

Jirka

From d3e1968ff94e735a0761036cb795cbee4c06937e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ji=C5=99=C3=AD=20Klime=C5=A1?= <jklimes redhat com>
Date: Fri, 20 May 2011 13:45:12 +0200
Subject: [PATCH] policy: remove connection "invalid mark" after 5 mins to
 auto-activate again
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

When there is a temporary connection failure (e.g. due to unavailable DHCP),
auto-activated connection is marked as invalid after several retries. Reset the
flag after 5 mins to allow next auto-reconnection.

Signed-off-by: Jiří Klimeš <jklimes redhat com>
---
 src/nm-policy.c |   56 ++++++++++++++++++++++++++++++++++++++++++++----------
 1 files changed, 45 insertions(+), 11 deletions(-)

diff --git a/src/nm-policy.c b/src/nm-policy.c
index 194d111..5b13fff 100644
--- a/src/nm-policy.c
+++ b/src/nm-policy.c
@@ -72,6 +72,7 @@ struct NMPolicy {
 
 #define RETRIES_TAG "autoconnect-retries"
 #define RETRIES_DEFAULT	4
+#define RESET_RETRIES_TIMEOUT 300
 
 static NMDevice *
 get_best_ip4_device (NMManager *manager, NMActRequest **out_req)
@@ -864,6 +865,38 @@ schedule_activate_check (NMPolicy *policy, NMDevice *device, guint delay_seconds
 	}
 }
 
+static void
+schedule_activate_all (NMPolicy *policy)
+{
+	GSList *iter, *devices;
+
+	devices = nm_manager_get_devices (policy->manager);
+	for (iter = devices; iter; iter = g_slist_next (iter))
+		schedule_activate_check (policy, NM_DEVICE (iter->data), 0);
+}
+
+typedef struct {
+	NMConnection *connection;
+	NMPolicy *policy;
+} ResetRetriesData;
+
+static gboolean
+reset_connection_retries (gpointer user_data)
+{
+	ResetRetriesData *data = (ResetRetriesData *) user_data;
+	NMConnection *connection = NM_CONNECTION (data->connection);
+	NMPolicy *policy = (NMPolicy *) data->policy;
+
+	/* If the connection is still invalid, reset auto retries back to default */
+	if (get_connection_auto_retries (connection) == 0)
+		set_connection_auto_retries (connection, RETRIES_DEFAULT);
+
+	schedule_activate_all (policy);
+
+	g_free (user_data);
+	return FALSE;
+}
+
 static NMConnection *
 get_device_connection (NMDevice *device)
 {
@@ -908,8 +941,19 @@ device_state_changed (NMDevice *device,
 				set_connection_auto_retries (connection, tries - 1);
 			}
 
-			if (get_connection_auto_retries (connection) == 0)
+			if (get_connection_auto_retries (connection) == 0) {
+				ResetRetriesData *reset_data;
+
 				nm_log_info (LOGD_DEVICE, "Marking connection '%s' invalid.", nm_connection_get_id (connection));
+
+				reset_data = g_malloc0 (sizeof (ResetRetriesData));
+				reset_data->connection = connection;
+				reset_data->policy = policy;
+
+				/* Schedule timeout for resetting RETRIES_TAG so that the connection can be auto-activated again.
+				 * That handles e.g. temporary unavailable DHCP server, and such cases. */
+				g_timeout_add_seconds (RESET_RETRIES_TIMEOUT, reset_connection_retries, reset_data);
+			}
 			nm_connection_clear_secrets (connection);
 		}
 		schedule_activate_check (policy, device, 3);
@@ -1032,16 +1076,6 @@ device_removed (NMManager *manager, NMDevice *device, gpointer user_data)
 }
 
 static void
-schedule_activate_all (NMPolicy *policy)
-{
-	GSList *iter, *devices;
-
-	devices = nm_manager_get_devices (policy->manager);
-	for (iter = devices; iter; iter = g_slist_next (iter))
-		schedule_activate_check (policy, NM_DEVICE (iter->data), 0);
-}
-
-static void
 connection_added (NMSettings *settings,
                   NMConnection *connection,
                   gpointer user_data)
-- 
1.7.5.1