/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * 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 version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 */

#define DEBUG_SUBSYSTEM S_SEC
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/dcache.h>
#include <linux/fs.h>
#include <linux/mutex.h>

#include <obd.h>
#include <obd_class.h>
#include <obd_support.h>
#include <lustre/lustre_idl.h>
#include <lustre_net.h>
#include <lustre_import.h>
#include <lprocfs_status.h>
#include <lustre_sec.h>

#include "gss_err.h"
#include "gss_internal.h"
#include "gss_api.h"

static struct proc_dir_entry *gss_proc_root = NULL;
static struct proc_dir_entry *gss_proc_lk = NULL;

/*
 * statistic of "out-of-sequence-window"
 */
static struct {
	spinlock_t  oos_lock;
	atomic_t    oos_cli_count;       /* client occurrence */
	int	     oos_cli_behind;      /* client max seqs behind */
	atomic_t    oos_svc_replay[3];   /* server replay detected */
	atomic_t    oos_svc_pass[3];     /* server verified ok */
} gss_stat_oos = {
	.oos_cli_count  = ATOMIC_INIT(0),
	.oos_cli_behind = 0,
	.oos_svc_replay = { ATOMIC_INIT(0), },
	.oos_svc_pass   = { ATOMIC_INIT(0), },
};

void gss_stat_oos_record_cli(int behind)
{
	atomic_inc(&gss_stat_oos.oos_cli_count);

	spin_lock(&gss_stat_oos.oos_lock);
	if (behind > gss_stat_oos.oos_cli_behind)
		gss_stat_oos.oos_cli_behind = behind;
	spin_unlock(&gss_stat_oos.oos_lock);
}

void gss_stat_oos_record_svc(int phase, int replay)
{
	LASSERT(phase >= 0 && phase <= 2);

	if (replay)
		atomic_inc(&gss_stat_oos.oos_svc_replay[phase]);
	else
		atomic_inc(&gss_stat_oos.oos_svc_pass[phase]);
}

static int gss_proc_oos_seq_show(struct seq_file *m, void *v)
{
	return seq_printf(m,
			"seqwin:		%u\n"
			"backwin:	       %u\n"
			"client fall behind seqwin\n"
			"  occurrence:	  %d\n"
			"  max seq behind:      %d\n"
			"server replay detected:\n"
			"  phase 0:	     %d\n"
			"  phase 1:	     %d\n"
			"  phase 2:	     %d\n"
			"server verify ok:\n"
			"  phase 2:	     %d\n",
			GSS_SEQ_WIN_MAIN,
			GSS_SEQ_WIN_BACK,
			atomic_read(&gss_stat_oos.oos_cli_count),
			gss_stat_oos.oos_cli_behind,
			atomic_read(&gss_stat_oos.oos_svc_replay[0]),
			atomic_read(&gss_stat_oos.oos_svc_replay[1]),
			atomic_read(&gss_stat_oos.oos_svc_replay[2]),
			atomic_read(&gss_stat_oos.oos_svc_pass[2]));
}
LPROC_SEQ_FOPS_RO(gss_proc_oos);

static int gss_proc_write_secinit(struct file *file, const char *buffer,
				  size_t count, off_t *off)
{
	int rc;

	rc = gss_do_ctx_init_rpc((char *) buffer, count);
	if (rc) {
		LASSERT(rc < 0);
		return rc;
	}

	return count;
}

static const struct file_operations gss_proc_secinit = {
	.write = gss_proc_write_secinit,
};

static struct lprocfs_vars gss_lprocfs_vars[] = {
	{ "replays", &gss_proc_oos_fops },
	{ "init_channel", &gss_proc_secinit, NULL, 0222 },
	{ NULL }
};

/*
 * for userspace helper lgss_keyring.
 *
 * debug_level: [0, 4], defined in utils/gss/lgss_utils.h
 */
static int gss_lk_debug_level = 1;

static int gss_lk_proc_dl_seq_show(struct seq_file *m, void *v)
{
	return seq_printf(m, "%u\n", gss_lk_debug_level);
}

static int gss_lk_proc_dl_seq_write(struct file *file, const char *buffer,
				    size_t count, off_t *off)
{
	int     val, rc;

	rc = lprocfs_write_helper(buffer, count, &val);
	if (rc < 0)
		return rc;

	if (val < 0 || val > 4)
		return -ERANGE;

	gss_lk_debug_level = val;
	return count;
}
LPROC_SEQ_FOPS(gss_lk_proc_dl);

static struct lprocfs_vars gss_lk_lprocfs_vars[] = {
	{ "debug_level", &gss_lk_proc_dl_fops },
	{ NULL }
};

void gss_exit_lproc(void)
{
	if (gss_proc_lk) {
		lprocfs_remove(&gss_proc_lk);
		gss_proc_lk = NULL;
	}

	if (gss_proc_root) {
		lprocfs_remove(&gss_proc_root);
		gss_proc_root = NULL;
	}
}

int gss_init_lproc(void)
{
	int     rc;

	spin_lock_init(&gss_stat_oos.oos_lock);

	gss_proc_root = lprocfs_register("gss", sptlrpc_proc_root,
					 gss_lprocfs_vars, NULL);
	if (IS_ERR(gss_proc_root)) {
		rc = PTR_ERR(gss_proc_root);
		gss_proc_root = NULL;
		GOTO(err_out, rc);
	}

	gss_proc_lk = lprocfs_register("lgss_keyring", gss_proc_root,
				       gss_lk_lprocfs_vars, NULL);
	if (IS_ERR(gss_proc_lk)) {
		rc = PTR_ERR(gss_proc_lk);
		gss_proc_lk = NULL;
		GOTO(err_out, rc);
	}

	return 0;

err_out:
	CERROR("failed to initialize gss lproc entries: %d\n", rc);
	gss_exit_lproc();
	return rc;
}