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-rw-r--r--src/sync-alarm.c104
1 files changed, 104 insertions, 0 deletions
diff --git a/src/sync-alarm.c b/src/sync-alarm.c
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+++ b/src/sync-alarm.c
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+/*
+ * (C) 2006-2007 by Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "conntrackd.h"
+#include "sync.h"
+#include "network.h"
+#include "us-conntrack.h"
+#include "alarm.h"
+
+static void refresher(struct alarm_list *a, void *data)
+{
+ int len;
+ struct nethdr *net;
+ struct us_conntrack *u = data;
+
+ debug_ct(u->ct, "persistence update");
+
+ a->expires = random() % CONFIG(refresh) + 1;
+ net = BUILD_NETMSG(u->ct, NFCT_Q_UPDATE);
+ len = prepare_send_netmsg(STATE_SYNC(mcast_client), net);
+ mcast_buffered_send_netmsg(STATE_SYNC(mcast_client), net, len);
+}
+
+static void cache_alarm_add(struct us_conntrack *u, void *data)
+{
+ struct alarm_list *alarm = data;
+
+ init_alarm(alarm);
+ set_alarm_expiration(alarm, (random() % conf.refresh) + 1);
+ set_alarm_data(alarm, u);
+ set_alarm_function(alarm, refresher);
+ add_alarm(alarm);
+}
+
+static void cache_alarm_update(struct us_conntrack *u, void *data)
+{
+ struct alarm_list *alarm = data;
+ mod_alarm(alarm, (random() % conf.refresh) + 1);
+}
+
+static void cache_alarm_destroy(struct us_conntrack *u, void *data)
+{
+ struct alarm_list *alarm = data;
+ del_alarm(alarm);
+}
+
+static struct cache_extra cache_alarm_extra = {
+ .size = sizeof(struct alarm_list),
+ .add = cache_alarm_add,
+ .update = cache_alarm_update,
+ .destroy = cache_alarm_destroy
+};
+
+static int alarm_recv(const struct nethdr *net)
+{
+ unsigned int exp_seq;
+
+ /*
+ * Ignore error messages: Although this message type is not ever
+ * generated in alarm mode, we don't want to crash the daemon
+ * if someone nuts mixes ftfw and alarm.
+ */
+ if (net->flags)
+ return 1;
+
+ /*
+ * Multicast sequence tracking: we keep track of multicast messages
+ * although we don't do any explicit message recovery. So, why do
+ * we do sequence tracking? Just to let know the sysadmin.
+ *
+ * Let t be 1 < t < RefreshTime. To ensure consistency, conntrackd
+ * retransmit every t seconds a message with the state of a certain
+ * entry even if such entry did not change. This mechanism also
+ * provides passive resynchronization, in other words, there is
+ * no facility to request a full synchronization from new nodes that
+ * just joined the cluster, instead they just get resynchronized in
+ * RefreshTime seconds at worst case.
+ */
+ mcast_track_seq(net->seq, &exp_seq);
+
+ return 0;
+}
+
+struct sync_mode alarm = {
+ .internal_cache_flags = LIFETIME,
+ .external_cache_flags = TIMER | LIFETIME,
+ .internal_cache_extra = &cache_alarm_extra,
+ .recv = alarm_recv,
+};