[Sheepdog] [PATCH v2 1/6] sheep: define cluster driver interface

[MORITA Kazutaka]

This patch abstracts out a cluster management of Sheepdog, and
introduces a cluster driver interface.

Signed-off-by: MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp>
---
 sheep/cluster.h |  157 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 157 insertions(+), 0 deletions(-)
 create mode 100644 sheep/cluster.h

diff --git a/sheep/cluster.h b/sheep/cluster.h
new file mode 100644
index 0000000..ce1074d
--- /dev/null
+++ b/sheep/cluster.h
@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2011 Nippon Telegraph and Telephone Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef __CLUSTER_H__
+#define __CLUSTER_H__
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <memory.h>
+
+#include "sheepdog_proto.h"
+#include "sheep.h"
+#include "logger.h"
+
+struct sheepid {
+	uint8_t addr[16];
+	uint64_t pid;
+};
+
+struct cdrv_handlers {
+	void (*join_handler)(struct sheepid *joined, struct sheepid *members,
+			     size_t nr_members);
+	void (*leave_handler)(struct sheepid *left, struct sheepid *members,
+			      size_t nr_members);
+	void (*notify_handler)(struct sheepid *sender, void *msg, size_t msg_len);
+};
+
+struct cluster_driver {
+	const char *name;
+
+	/*
+	 * Initialize the cluster driver
+	 *
+	 * On success, this function returns the file descriptor that
+	 * may be used with the poll(2) to monitor cluster events.  On
+	 * error, returns -1.
+	 */
+	int (*init)(struct cdrv_handlers *handlers, struct sheepid *myid);
+
+	/*
+	 * Join the cluster
+	 *
+	 * This function is used to join the cluster, and notifies a
+	 * join event to all the nodes.
+	 *
+	 * Returns zero on success, -1 on error
+	 */
+	int (*join)(void);
+
+	/*
+	 * Leave the cluster
+	 *
+	 * This function is used to leave the cluster, and notifies a
+	 * leave event to all the nodes.
+	 *
+	 * Returns zero on success, -1 on error
+	 */
+	int (*leave)(void);
+
+	/*
+	 * Notify a message to all nodes in the cluster
+	 *
+	 * This function sends 'msg' to all the nodes.  The notified
+	 * messages can be read through notify_handler() in
+	 * cdrv_handlers.
+	 *
+	 * Returns zero on success, -1 on error
+	 */
+	int (*notify)(void *msg, size_t msg_len);
+
+	/*
+	 * Dispatch handlers
+	 *
+	 * This function dispatches handlers according to the
+	 * delivered events (join/leave/notify) in the cluster.
+	 *
+	 * Note that the events sequence is totally ordered; all nodes
+	 * call the handlers in the same sequence.
+	 *
+	 * Returns zero on success, -1 on error
+	 */
+	int (*dispatch)(void);
+
+	struct list_head list;
+};
+
+extern struct list_head cluster_drivers;
+
+#define cdrv_register(driver)						\
+static void __attribute__((constructor)) regist_ ## driver(void) {	\
+	list_add(&driver.list, &cluster_drivers);			\
+}
+
+#define FOR_EACH_CLUSTER_DRIVER(driver) \
+	list_for_each_entry(driver, &cluster_drivers, list)
+
+
+static inline int sheepid_find(struct sheepid *sheeps, size_t nr_sheeps,
+			       struct sheepid *key)
+{
+	int i;
+
+	for (i = 0; i < nr_sheeps; i++) {
+		if (memcmp(sheeps + i, key, sizeof(*key)) == 0)
+			return i;
+	}
+	return -1;
+}
+
+static inline void sheepid_add(struct sheepid *sheeps1, size_t nr_sheeps1,
+			       struct sheepid *sheeps2, size_t nr_sheeps2)
+{
+	memcpy(sheeps1 + nr_sheeps1, sheeps2, sizeof(*sheeps2) * nr_sheeps2);
+}
+
+static inline void sheepid_del(struct sheepid *sheeps1, size_t nr_sheeps1,
+			       struct sheepid *sheeps2, size_t nr_sheeps2)
+{
+	int i, idx;
+
+	for (i = 0; i < nr_sheeps2; i++) {
+		idx = sheepid_find(sheeps1, nr_sheeps1, sheeps2 + i);
+		if (idx < 0)
+			panic("internal error: cannot find sheepid\n");
+
+		nr_sheeps1--;
+		memmove(sheeps1 + idx, sheeps1 + idx + 1,
+			sizeof(*sheeps1) * nr_sheeps1 - idx);
+	}
+}
+
+static inline char *sheepid_to_str(struct sheepid *id)
+{
+	static char str[256];
+	char name[256];
+
+	snprintf(str, sizeof(str), "ip: %s, pid: %" PRIu64,
+		 addr_to_str(name, sizeof(name), id->addr, 0), id->pid);
+
+	return str;
+}
+
+static inline int sheepid_cmp(struct sheepid *id1, struct sheepid *id2)
+{
+	return memcmp(id1, id2, sizeof(*id1));
+}
+
+#endif
-- 
1.7.2.5