1 files changed, 234 insertions, 0 deletions
diff --git a/ctdb/server/ctdb_keepalive.c b/ctdb/server/ctdb_keepalive.c
new file mode 100644
index 0000000..9155ade
--- /dev/null
+++ b/ctdb/server/ctdb_keepalive.c
@@ -0,0 +1,234 @@
+/* 
+   monitoring links to all other nodes to detect dead nodes
+
+
+   Copyright (C) Ronnie Sahlberg 2007
+
+   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 3 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, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "replace.h"
+#include "system/filesys.h"
+#include "system/network.h"
+#include "system/time.h"
+#include "system/wait.h"
+
+#include <talloc.h>
+#include <tevent.h>
+
+#include "lib/util/debug.h"
+#include "lib/util/samba_util.h"
+
+#include "ctdb_private.h"
+#include "version.h"
+
+#include "common/common.h"
+#include "common/logging.h"
+
+
+static uint32_t keepalive_version(void)
+{
+	static uint32_t version = 0;
+
+	if (version == 0) {
+		const char *t;
+
+		version = (SAMBA_VERSION_MAJOR << 16) | SAMBA_VERSION_MINOR;
+
+		t = getenv("CTDB_TEST_SAMBA_VERSION");
+		if (t != NULL) {
+			int v;
+
+			v = atoi(t);
+			if (v <= 0) {
+				DBG_WARNING("Failed to parse env var: %s\n", t);
+			} else {
+				version = v;
+			}
+		}
+	}
+
+	return version;
+}
+
+static uint32_t keepalive_uptime(struct ctdb_context *ctdb)
+{
+	struct timeval current = tevent_timeval_current();
+
+	return current.tv_sec - ctdb->ctdbd_start_time.tv_sec;
+}
+
+/*
+   send a keepalive packet to the other node
+*/
+static void ctdb_send_keepalive(struct ctdb_context *ctdb, uint32_t destnode)
+{
+	struct ctdb_req_keepalive_old *r;
+
+	if (ctdb->methods == NULL) {
+		DEBUG(DEBUG_INFO,
+		      ("Failed to send keepalive. Transport is DOWN\n"));
+		return;
+	}
+
+	r = ctdb_transport_allocate(ctdb, ctdb, CTDB_REQ_KEEPALIVE,
+				    sizeof(struct ctdb_req_keepalive_old),
+				    struct ctdb_req_keepalive_old);
+	CTDB_NO_MEMORY_FATAL(ctdb, r);
+	r->hdr.destnode  = destnode;
+	r->hdr.reqid     = 0;
+
+	r->version = keepalive_version();
+	r->uptime = keepalive_uptime(ctdb);
+
+	CTDB_INCREMENT_STAT(ctdb, keepalive_packets_sent);
+
+	ctdb_queue_packet(ctdb, &r->hdr);
+
+	talloc_free(r);
+}
+
+/*
+  see if any nodes are dead
+ */
+static void ctdb_check_for_dead_nodes(struct tevent_context *ev,
+				      struct tevent_timer *te,
+				      struct timeval t, void *private_data)
+{
+	struct ctdb_context *ctdb = talloc_get_type(private_data, struct ctdb_context);
+	unsigned int i;
+
+	/* send a keepalive to all other nodes, unless */
+	for (i=0;i<ctdb->num_nodes;i++) {
+		struct ctdb_node *node = ctdb->nodes[i];
+
+		if (node->flags & NODE_FLAGS_DELETED) {
+			continue;
+		}
+
+		if (node->pnn == ctdb->pnn) {
+			continue;
+		}
+		
+		if (node->flags & NODE_FLAGS_DISCONNECTED) {
+			/* it might have come alive again */
+			if (node->rx_cnt != 0) {
+				ctdb_node_connected(node);
+			}
+			continue;
+		}
+
+
+		if (node->rx_cnt == 0) {
+			node->dead_count++;
+		} else {
+			node->dead_count = 0;
+		}
+
+		node->rx_cnt = 0;
+
+		if (node->dead_count >= ctdb->tunable.keepalive_limit) {
+			DEBUG(DEBUG_NOTICE,("dead count reached for node %u\n", node->pnn));
+			ctdb_node_dead(node);
+			ctdb_send_keepalive(ctdb, node->pnn);
+			/* maybe tell the transport layer to kill the
+			   sockets as well?
+			*/
+			continue;
+		}
+		
+		DEBUG(DEBUG_DEBUG,("sending keepalive to %u\n", node->pnn));
+		ctdb_send_keepalive(ctdb, node->pnn);
+
+		node->tx_cnt = 0;
+	}
+
+	tevent_add_timer(ctdb->ev, ctdb->keepalive_ctx,
+			 timeval_current_ofs(ctdb->tunable.keepalive_interval, 0),
+			 ctdb_check_for_dead_nodes, ctdb);
+}
+
+
+void ctdb_start_keepalive(struct ctdb_context *ctdb)
+{
+	struct tevent_timer *te;
+
+	ctdb->keepalive_ctx = talloc_new(ctdb);
+	CTDB_NO_MEMORY_FATAL(ctdb, ctdb->keepalive_ctx);
+
+	te = tevent_add_timer(ctdb->ev, ctdb->keepalive_ctx,
+			      timeval_current_ofs(ctdb->tunable.keepalive_interval, 0),
+			      ctdb_check_for_dead_nodes, ctdb);
+	CTDB_NO_MEMORY_FATAL(ctdb, te);
+
+	DEBUG(DEBUG_NOTICE,("Keepalive monitoring has been started\n"));
+
+	if (ctdb->tunable.allow_mixed_versions == 1) {
+		DEBUG(DEBUG_WARNING,
+		      ("CTDB cluster with mixed versions configured\n"));
+	}
+}
+
+void ctdb_stop_keepalive(struct ctdb_context *ctdb)
+{
+	talloc_free(ctdb->keepalive_ctx);
+	ctdb->keepalive_ctx = NULL;
+}
+
+void ctdb_request_keepalive(struct ctdb_context *ctdb,
+			    struct ctdb_req_header *hdr)
+{
+	struct ctdb_req_keepalive_old *c =
+		(struct ctdb_req_keepalive_old *)hdr;
+	uint32_t my_version = keepalive_version();
+	uint32_t my_uptime = keepalive_uptime(ctdb);
+
+	/* Don't check anything if mixed versions are allowed */
+	if (ctdb->tunable.allow_mixed_versions == 1) {
+		return;
+	}
+
+	if (hdr->length == sizeof(struct ctdb_req_header)) {
+		/* Old keepalive */
+		goto fail1;
+	}
+
+	if (c->version != my_version) {
+		if (c->uptime > my_uptime) {
+			goto fail2;
+		} else if (c->uptime == my_uptime) {
+			if (c->version > my_version) {
+				goto fail2;
+			}
+		}
+	}
+
+	return;
+
+fail1:
+	DEBUG(DEBUG_ERR,
+	      ("Keepalive version missing from node %u\n", hdr->srcnode));
+	goto shutdown;
+
+fail2:
+	DEBUG(DEBUG_ERR,
+	      ("Keepalive version mismatch 0x%08x != 0x%08x from node %u\n",
+	       my_version, c->version, hdr->srcnode));
+	goto shutdown;
+
+shutdown:
+	DEBUG(DEBUG_ERR,
+	      ("CTDB Cluster with mixed versions, cannot continue\n"));
+	ctdb_shutdown_sequence(ctdb, 0);
+}