/*******************************************************************************
 * Filename:  tcm_fc.c
 *
 * This file contains the configfs implementation for TCM_fc fabric node.
 * Based on tcm_loop_configfs.c
 *
 * Copyright (c) 2010 Cisco Systems, Inc.
 * Copyright (c) 2009,2010 Rising Tide, Inc.
 * Copyright (c) 2009,2010 Linux-iSCSI.org
 *
 * Copyright (c) 2009,2010 Nicholas A. Bellinger <nab@linux-iscsi.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.
 ****************************************************************************/

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <generated/utsrelease.h>
#include <linux/utsname.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/configfs.h>
#include <linux/kernel.h>
#include <linux/ctype.h>
#include <asm/unaligned.h>
#include <scsi/libfc.h>

#include <target/target_core_base.h>
#include <target/target_core_fabric.h>

#include "tcm_fc.h"

static LIST_HEAD(ft_wwn_list);
DEFINE_MUTEX(ft_lport_lock);

unsigned int ft_debug_logging;
module_param_named(debug_logging, ft_debug_logging, int, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(debug_logging, "a bit mask of logging levels");

/*
 * Parse WWN.
 * If strict, we require lower-case hex and colon separators to be sure
 * the name is the same as what would be generated by ft_format_wwn()
 * so the name and wwn are mapped one-to-one.
 */
static ssize_t ft_parse_wwn(const char *name, u64 *wwn, int strict)
{
	const char *cp;
	char c;
	u32 byte = 0;
	u32 pos = 0;
	u32 err;
	int val;

	*wwn = 0;
	for (cp = name; cp < &name[FT_NAMELEN - 1]; cp++) {
		c = *cp;
		if (c == '\n' && cp[1] == '\0')
			continue;
		if (strict && pos++ == 2 && byte++ < 7) {
			pos = 0;
			if (c == ':')
				continue;
			err = 1;
			goto fail;
		}
		if (c == '\0') {
			err = 2;
			if (strict && byte != 8)
				goto fail;
			return cp - name;
		}
		err = 3;
		val = hex_to_bin(c);
		if (val < 0 || (strict && isupper(c)))
			goto fail;
		*wwn = (*wwn << 4) | val;
	}
	err = 4;
fail:
	pr_debug("err %u len %zu pos %u byte %u\n",
		    err, cp - name, pos, byte);
	return -1;
}

ssize_t ft_format_wwn(char *buf, size_t len, u64 wwn)
{
	u8 b[8];

	put_unaligned_be64(wwn, b);
	return snprintf(buf, len,
		 "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x",
		 b[0], b[1], b[2], b[3], b[4], b[5], b[6], b[7]);
}

static ssize_t ft_wwn_show(void *arg, char *buf)
{
	u64 *wwn = arg;
	ssize_t len;

	len = ft_format_wwn(buf, PAGE_SIZE - 2, *wwn);
	buf[len++] = '\n';
	return len;
}

static ssize_t ft_wwn_store(void *arg, const char *buf, size_t len)
{
	ssize_t ret;
	u64 wwn;

	ret = ft_parse_wwn(buf, &wwn, 0);
	if (ret > 0)
		*(u64 *)arg = wwn;
	return ret;
}

/*
 * ACL auth ops.
 */

static ssize_t ft_nacl_port_name_show(struct config_item *item, char *page)
{
	struct se_node_acl *se_nacl = acl_to_nacl(item);
	struct ft_node_acl *acl = container_of(se_nacl,
			struct ft_node_acl, se_node_acl);

	return ft_wwn_show(&acl->node_auth.port_name, page);
}

static ssize_t ft_nacl_port_name_store(struct config_item *item,
		const char *page, size_t count)
{
	struct se_node_acl *se_nacl = acl_to_nacl(item);
	struct ft_node_acl *acl = container_of(se_nacl,
			struct ft_node_acl, se_node_acl);

	return ft_wwn_store(&acl->node_auth.port_name, page, count);
}

static ssize_t ft_nacl_node_name_show(struct config_item *item,
		char *page)
{
	struct se_node_acl *se_nacl = acl_to_nacl(item);
	struct ft_node_acl *acl = container_of(se_nacl,
			struct ft_node_acl, se_node_acl);

	return ft_wwn_show(&acl->node_auth.node_name, page);
}

static ssize_t ft_nacl_node_name_store(struct config_item *item,
		const char *page, size_t count)
{
	struct se_node_acl *se_nacl = acl_to_nacl(item);
	struct ft_node_acl *acl = container_of(se_nacl,
			struct ft_node_acl, se_node_acl);

	return ft_wwn_store(&acl->node_auth.node_name, page, count);
}

CONFIGFS_ATTR(ft_nacl_, node_name);
CONFIGFS_ATTR(ft_nacl_, port_name);

static ssize_t ft_nacl_tag_show(struct config_item *item,
		char *page)
{
	return snprintf(page, PAGE_SIZE, "%s", acl_to_nacl(item)->acl_tag);
}

static ssize_t ft_nacl_tag_store(struct config_item *item,
		const char *page, size_t count)
{
	struct se_node_acl *se_nacl = acl_to_nacl(item);
	int ret;

	ret = core_tpg_set_initiator_node_tag(se_nacl->se_tpg, se_nacl, page);

	if (ret < 0)
		return ret;
	return count;
}

CONFIGFS_ATTR(ft_nacl_, tag);

static struct configfs_attribute *ft_nacl_base_attrs[] = {
	&ft_nacl_attr_port_name,
	&ft_nacl_attr_node_name,
	&ft_nacl_attr_tag,
	NULL,
};

/*
 * ACL ops.
 */

/*
 * Add ACL for an initiator.  The ACL is named arbitrarily.
 * The port_name and/or node_name are attributes.
 */
static int ft_init_nodeacl(struct se_node_acl *nacl, const char *name)
{
	struct ft_node_acl *acl =
		container_of(nacl, struct ft_node_acl, se_node_acl);
	u64 wwpn;

	if (ft_parse_wwn(name, &wwpn, 1) < 0)
		return -EINVAL;

	acl->node_auth.port_name = wwpn;
	return 0;
}

/*
 * local_port port_group (tpg) ops.
 */
static struct se_portal_group *ft_add_tpg(
	struct se_wwn *wwn,
	struct config_group *group,
	const char *name)
{
	struct ft_lport_wwn *ft_wwn;
	struct ft_tpg *tpg;
	struct workqueue_struct *wq;
	unsigned long index;
	int ret;

	pr_debug("tcm_fc: add tpg %s\n", name);

	/*
	 * Name must be "tpgt_" followed by the index.
	 */
	if (strstr(name, "tpgt_") != name)
		return NULL;

	ret = kstrtoul(name + 5, 10, &index);
	if (ret)
		return NULL;
	if (index > UINT_MAX)
		return NULL;

	if ((index != 1)) {
		pr_err("Error, a single TPG=1 is used for HW port mappings\n");
		return ERR_PTR(-ENOSYS);
	}

	ft_wwn = container_of(wwn, struct ft_lport_wwn, se_wwn);
	tpg = kzalloc(sizeof(*tpg), GFP_KERNEL);
	if (!tpg)
		return NULL;
	tpg->index = index;
	tpg->lport_wwn = ft_wwn;
	INIT_LIST_HEAD(&tpg->lun_list);

	wq = alloc_workqueue("tcm_fc", 0, 1);
	if (!wq) {
		kfree(tpg);
		return NULL;
	}

	ret = core_tpg_register(wwn, &tpg->se_tpg, SCSI_PROTOCOL_FCP);
	if (ret < 0) {
		destroy_workqueue(wq);
		kfree(tpg);
		return NULL;
	}
	tpg->workqueue = wq;

	mutex_lock(&ft_lport_lock);
	ft_wwn->tpg = tpg;
	mutex_unlock(&ft_lport_lock);

	return &tpg->se_tpg;
}

static void ft_del_tpg(struct se_portal_group *se_tpg)
{
	struct ft_tpg *tpg = container_of(se_tpg, struct ft_tpg, se_tpg);
	struct ft_lport_wwn *ft_wwn = tpg->lport_wwn;

	pr_debug("del tpg %s\n",
		    config_item_name(&tpg->se_tpg.tpg_group.cg_item));

	destroy_workqueue(tpg->workqueue);

	/* Wait for sessions to be freed thru RCU, for BUG_ON below */
	synchronize_rcu();

	mutex_lock(&ft_lport_lock);
	ft_wwn->tpg = NULL;
	if (tpg->tport) {
		tpg->tport->tpg = NULL;
		tpg->tport = NULL;
	}
	mutex_unlock(&ft_lport_lock);

	core_tpg_deregister(se_tpg);
	kfree(tpg);
}

/*
 * Verify that an lport is configured to use the tcm_fc module, and return
 * the target port group that should be used.
 *
 * The caller holds ft_lport_lock.
 */
struct ft_tpg *ft_lport_find_tpg(struct fc_lport *lport)
{
	struct ft_lport_wwn *ft_wwn;

	list_for_each_entry(ft_wwn, &ft_wwn_list, ft_wwn_node) {
		if (ft_wwn->wwpn == lport->wwpn)
			return ft_wwn->tpg;
	}
	return NULL;
}

/*
 * target config instance ops.
 */

/*
 * Add lport to allowed config.
 * The name is the WWPN in lower-case ASCII, colon-separated bytes.
 */
static struct se_wwn *ft_add_wwn(
	struct target_fabric_configfs *tf,
	struct config_group *group,
	const char *name)
{
	struct ft_lport_wwn *ft_wwn;
	struct ft_lport_wwn *old_ft_wwn;
	u64 wwpn;

	pr_debug("add wwn %s\n", name);
	if (ft_parse_wwn(name, &wwpn, 1) < 0)
		return NULL;
	ft_wwn = kzalloc(sizeof(*ft_wwn), GFP_KERNEL);
	if (!ft_wwn)
		return NULL;
	ft_wwn->wwpn = wwpn;

	mutex_lock(&ft_lport_lock);
	list_for_each_entry(old_ft_wwn, &ft_wwn_list, ft_wwn_node) {
		if (old_ft_wwn->wwpn == wwpn) {
			mutex_unlock(&ft_lport_lock);
			kfree(ft_wwn);
			return NULL;
		}
	}
	list_add_tail(&ft_wwn->ft_wwn_node, &ft_wwn_list);
	ft_format_wwn(ft_wwn->name, sizeof(ft_wwn->name), wwpn);
	mutex_unlock(&ft_lport_lock);

	return &ft_wwn->se_wwn;
}

static void ft_del_wwn(struct se_wwn *wwn)
{
	struct ft_lport_wwn *ft_wwn = container_of(wwn,
				struct ft_lport_wwn, se_wwn);

	pr_debug("del wwn %s\n", ft_wwn->name);
	mutex_lock(&ft_lport_lock);
	list_del(&ft_wwn->ft_wwn_node);
	mutex_unlock(&ft_lport_lock);

	kfree(ft_wwn);
}

static ssize_t ft_wwn_version_show(struct config_item *item, char *page)
{
	return sprintf(page, "TCM FC " FT_VERSION " on %s/%s on "
		""UTS_RELEASE"\n",  utsname()->sysname, utsname()->machine);
}

CONFIGFS_ATTR_RO(ft_wwn_, version);

static struct configfs_attribute *ft_wwn_attrs[] = {
	&ft_wwn_attr_version,
	NULL,
};

static inline struct ft_tpg *ft_tpg(struct se_portal_group *se_tpg)
{
	return container_of(se_tpg, struct ft_tpg, se_tpg);
}

static char *ft_get_fabric_name(void)
{
	return "fc";
}

static char *ft_get_fabric_wwn(struct se_portal_group *se_tpg)
{
	return ft_tpg(se_tpg)->lport_wwn->name;
}

static u16 ft_get_tag(struct se_portal_group *se_tpg)
{
	/*
	 * This tag is used when forming SCSI Name identifier in EVPD=1 0x83
	 * to represent the SCSI Target Port.
	 */
	return ft_tpg(se_tpg)->index;
}

static int ft_check_false(struct se_portal_group *se_tpg)
{
	return 0;
}

static void ft_set_default_node_attr(struct se_node_acl *se_nacl)
{
}

static u32 ft_tpg_get_inst_index(struct se_portal_group *se_tpg)
{
	return ft_tpg(se_tpg)->index;
}

static const struct target_core_fabric_ops ft_fabric_ops = {
	.module =			THIS_MODULE,
	.name =				"fc",
	.node_acl_size =		sizeof(struct ft_node_acl),
	.get_fabric_name =		ft_get_fabric_name,
	.tpg_get_wwn =			ft_get_fabric_wwn,
	.tpg_get_tag =			ft_get_tag,
	.tpg_check_demo_mode =		ft_check_false,
	.tpg_check_demo_mode_cache =	ft_check_false,
	.tpg_check_demo_mode_write_protect = ft_check_false,
	.tpg_check_prod_mode_write_protect = ft_check_false,
	.tpg_get_inst_index =		ft_tpg_get_inst_index,
	.check_stop_free =		ft_check_stop_free,
	.release_cmd =			ft_release_cmd,
	.shutdown_session =		ft_sess_shutdown,
	.close_session =		ft_sess_close,
	.sess_get_index =		ft_sess_get_index,
	.sess_get_initiator_sid =	NULL,
	.write_pending =		ft_write_pending,
	.write_pending_status =		ft_write_pending_status,
	.set_default_node_attributes =	ft_set_default_node_attr,
	.get_cmd_state =		ft_get_cmd_state,
	.queue_data_in =		ft_queue_data_in,
	.queue_status =			ft_queue_status,
	.queue_tm_rsp =			ft_queue_tm_resp,
	.aborted_task =			ft_aborted_task,
	/*
	 * Setup function pointers for generic logic in
	 * target_core_fabric_configfs.c
	 */
	.fabric_make_wwn =		&ft_add_wwn,
	.fabric_drop_wwn =		&ft_del_wwn,
	.fabric_make_tpg =		&ft_add_tpg,
	.fabric_drop_tpg =		&ft_del_tpg,
	.fabric_init_nodeacl =		&ft_init_nodeacl,

	.tfc_wwn_attrs			= ft_wwn_attrs,
	.tfc_tpg_nacl_base_attrs	= ft_nacl_base_attrs,
};

static struct notifier_block ft_notifier = {
	.notifier_call = ft_lport_notify
};

static int __init ft_init(void)
{
	int ret;

	ret = target_register_template(&ft_fabric_ops);
	if (ret)
		goto out;

	ret = fc_fc4_register_provider(FC_TYPE_FCP, &ft_prov);
	if (ret)
		goto out_unregister_template;

	blocking_notifier_chain_register(&fc_lport_notifier_head, &ft_notifier);
	fc_lport_iterate(ft_lport_add, NULL);
	return 0;

out_unregister_template:
	target_unregister_template(&ft_fabric_ops);
out:
	return ret;
}

static void __exit ft_exit(void)
{
	blocking_notifier_chain_unregister(&fc_lport_notifier_head,
					   &ft_notifier);
	fc_fc4_deregister_provider(FC_TYPE_FCP, &ft_prov);
	fc_lport_iterate(ft_lport_del, NULL);
	target_unregister_template(&ft_fabric_ops);
	synchronize_rcu();
}

MODULE_DESCRIPTION("FC TCM fabric driver " FT_VERSION);
MODULE_LICENSE("GPL");
module_init(ft_init);
module_exit(ft_exit);