/*******************************************************************************
 * 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 <linux/version.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/ctype.h>
#include <asm/unaligned.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/libfc.h>

#include <target/target_core_base.h>
#include <target/target_core_transport.h>
#include <target/target_core_fabric_ops.h>
#include <target/target_core_fabric_configfs.h>
#include <target/target_core_fabric_lib.h>
#include <target/target_core_device.h>
#include <target/target_core_tpg.h>
#include <target/target_core_configfs.h>
#include <target/configfs_macros.h>

#include "tcm_fc.h"

struct target_fabric_configfs *ft_configfs;

LIST_HEAD(ft_lport_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 nibble;
	u32 byte = 0;
	u32 pos = 0;
	u32 err;

	*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;
		if (isdigit(c))
			nibble = c - '0';
		else if (isxdigit(c) && (islower(c) || !strict))
			nibble = tolower(c) - 'a' + 10;
		else
			goto fail;
		*wwn = (*wwn << 4) | nibble;
	}
	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_show_port_name(
	struct se_node_acl *se_nacl,
	char *page)
{
	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_store_port_name(
	struct se_node_acl *se_nacl,
	const char *page,
	size_t count)
{
	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);
}

TF_NACL_BASE_ATTR(ft, port_name, S_IRUGO | S_IWUSR);

static ssize_t ft_nacl_show_node_name(
	struct se_node_acl *se_nacl,
	char *page)
{
	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_store_node_name(
	struct se_node_acl *se_nacl,
	const char *page,
	size_t count)
{
	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);
}

TF_NACL_BASE_ATTR(ft, node_name, S_IRUGO | S_IWUSR);

static struct configfs_attribute *ft_nacl_base_attrs[] = {
	&ft_nacl_port_name.attr,
	&ft_nacl_node_name.attr,
	NULL,
};

/*
 * ACL ops.
 */

/*
 * Add ACL for an initiator.  The ACL is named arbitrarily.
 * The port_name and/or node_name are attributes.
 */
static struct se_node_acl *ft_add_acl(
	struct se_portal_group *se_tpg,
	struct config_group *group,
	const char *name)
{
	struct ft_node_acl *acl;
	struct ft_tpg *tpg;
	u64 wwpn;
	u32 q_depth;

	pr_debug("add acl %s\n", name);
	tpg = container_of(se_tpg, struct ft_tpg, se_tpg);

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

	acl = kzalloc(sizeof(struct ft_node_acl), GFP_KERNEL);
	if (!acl)
		return ERR_PTR(-ENOMEM);
	acl->node_auth.port_name = wwpn;

	q_depth = 32;		/* XXX bogus default - get from tpg? */
	return core_tpg_add_initiator_node_acl(&tpg->se_tpg,
				&acl->se_node_acl, name, q_depth);
}

static void ft_del_acl(struct se_node_acl *se_acl)
{
	struct se_portal_group *se_tpg = se_acl->se_tpg;
	struct ft_tpg *tpg;
	struct ft_node_acl *acl = container_of(se_acl,
				struct ft_node_acl, se_node_acl);

	pr_debug("del acl %s\n",
		config_item_name(&se_acl->acl_group.cg_item));

	tpg = container_of(se_tpg, struct ft_tpg, se_tpg);
	pr_debug("del acl %p se_acl %p tpg %p se_tpg %p\n",
		    acl, se_acl, tpg, &tpg->se_tpg);

	core_tpg_del_initiator_node_acl(&tpg->se_tpg, se_acl, 1);
	kfree(acl);
}

struct ft_node_acl *ft_acl_get(struct ft_tpg *tpg, struct fc_rport_priv *rdata)
{
	struct ft_node_acl *found = NULL;
	struct ft_node_acl *acl;
	struct se_portal_group *se_tpg = &tpg->se_tpg;
	struct se_node_acl *se_acl;

	spin_lock_irq(&se_tpg->acl_node_lock);
	list_for_each_entry(se_acl, &se_tpg->acl_node_list, acl_list) {
		acl = container_of(se_acl, struct ft_node_acl, se_node_acl);
		pr_debug("acl %p port_name %llx\n",
			acl, (unsigned long long)acl->node_auth.port_name);
		if (acl->node_auth.port_name == rdata->ids.port_name ||
		    acl->node_auth.node_name == rdata->ids.node_name) {
			pr_debug("acl %p port_name %llx matched\n", acl,
				    (unsigned long long)rdata->ids.port_name);
			found = acl;
			/* XXX need to hold onto ACL */
			break;
		}
	}
	spin_unlock_irq(&se_tpg->acl_node_lock);
	return found;
}

struct se_node_acl *ft_tpg_alloc_fabric_acl(struct se_portal_group *se_tpg)
{
	struct ft_node_acl *acl;

	acl = kzalloc(sizeof(*acl), GFP_KERNEL);
	if (!acl) {
		pr_err("Unable to allocate struct ft_node_acl\n");
		return NULL;
	}
	pr_debug("acl %p\n", acl);
	return &acl->se_node_acl;
}

static void ft_tpg_release_fabric_acl(struct se_portal_group *se_tpg,
				      struct se_node_acl *se_acl)
{
	struct ft_node_acl *acl = container_of(se_acl,
				struct ft_node_acl, se_node_acl);

	pr_debug("acl %p\n", acl);
	kfree(acl);
}

/*
 * 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_acl *lacl;
	struct ft_tpg *tpg;
	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;
	if (strict_strtoul(name + 5, 10, &index) || index > UINT_MAX)
		return NULL;

	lacl = container_of(wwn, struct ft_lport_acl, fc_lport_wwn);
	tpg = kzalloc(sizeof(*tpg), GFP_KERNEL);
	if (!tpg)
		return NULL;
	tpg->index = index;
	tpg->lport_acl = lacl;
	INIT_LIST_HEAD(&tpg->lun_list);

	ret = core_tpg_register(&ft_configfs->tf_ops, wwn, &tpg->se_tpg,
				tpg, TRANSPORT_TPG_TYPE_NORMAL);
	if (ret < 0) {
		kfree(tpg);
		return NULL;
	}

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

	mutex_lock(&ft_lport_lock);
	list_add_tail(&tpg->list, &lacl->tpg_list);
	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);

	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);
	list_del(&tpg->list);
	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_acl *lacl;
	struct ft_tpg *tpg;

	list_for_each_entry(lacl, &ft_lport_list, list) {
		if (lacl->wwpn == lport->wwpn) {
			list_for_each_entry(tpg, &lacl->tpg_list, list)
				return tpg; /* XXX for now return first entry */
			return NULL;
		}
	}
	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_lport(
	struct target_fabric_configfs *tf,
	struct config_group *group,
	const char *name)
{
	struct ft_lport_acl *lacl;
	struct ft_lport_acl *old_lacl;
	u64 wwpn;

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

	mutex_lock(&ft_lport_lock);
	list_for_each_entry(old_lacl, &ft_lport_list, list) {
		if (old_lacl->wwpn == wwpn) {
			mutex_unlock(&ft_lport_lock);
			kfree(lacl);
			return NULL;
		}
	}
	list_add_tail(&lacl->list, &ft_lport_list);
	ft_format_wwn(lacl->name, sizeof(lacl->name), wwpn);
	mutex_unlock(&ft_lport_lock);

	return &lacl->fc_lport_wwn;
}

static void ft_del_lport(struct se_wwn *wwn)
{
	struct ft_lport_acl *lacl = container_of(wwn,
				struct ft_lport_acl, fc_lport_wwn);

	pr_debug("del lport %s\n",
			config_item_name(&wwn->wwn_group.cg_item));
	mutex_lock(&ft_lport_lock);
	list_del(&lacl->list);
	mutex_unlock(&ft_lport_lock);

	kfree(lacl);
}

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

TF_WWN_ATTR_RO(ft, version);

static struct configfs_attribute *ft_wwn_attrs[] = {
	&ft_wwn_version.attr,
	NULL,
};

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

static char *ft_get_fabric_wwn(struct se_portal_group *se_tpg)
{
	struct ft_tpg *tpg = se_tpg->se_tpg_fabric_ptr;

	return tpg->lport_acl->name;
}

static u16 ft_get_tag(struct se_portal_group *se_tpg)
{
	struct ft_tpg *tpg = se_tpg->se_tpg_fabric_ptr;

	/*
	 * This tag is used when forming SCSI Name identifier in EVPD=1 0x83
	 * to represent the SCSI Target Port.
	 */
	return tpg->index;
}

static u32 ft_get_default_depth(struct se_portal_group *se_tpg)
{
	return 1;
}

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 u16 ft_get_fabric_sense_len(void)
{
	return 0;
}

static u16 ft_set_fabric_sense_len(struct se_cmd *se_cmd, u32 sense_len)
{
	return 0;
}

static u32 ft_tpg_get_inst_index(struct se_portal_group *se_tpg)
{
	struct ft_tpg *tpg = se_tpg->se_tpg_fabric_ptr;

	return tpg->index;
}

static struct target_core_fabric_ops ft_fabric_ops = {
	.get_fabric_name =		ft_get_fabric_name,
	.get_fabric_proto_ident =	fc_get_fabric_proto_ident,
	.tpg_get_wwn =			ft_get_fabric_wwn,
	.tpg_get_tag =			ft_get_tag,
	.tpg_get_default_depth =	ft_get_default_depth,
	.tpg_get_pr_transport_id =	fc_get_pr_transport_id,
	.tpg_get_pr_transport_id_len =	fc_get_pr_transport_id_len,
	.tpg_parse_pr_out_transport_id = fc_parse_pr_out_transport_id,
	.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_alloc_fabric_acl =		ft_tpg_alloc_fabric_acl,
	.tpg_release_fabric_acl =	ft_tpg_release_fabric_acl,
	.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,
	.stop_session =			ft_sess_stop,
	.fall_back_to_erl0 =		ft_sess_set_erl0,
	.sess_logged_in =		ft_sess_logged_in,
	.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_task_tag =			ft_get_task_tag,
	.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,
	.get_fabric_sense_len =		ft_get_fabric_sense_len,
	.set_fabric_sense_len =		ft_set_fabric_sense_len,
	.is_state_remove =		ft_is_state_remove,
	/*
	 * Setup function pointers for generic logic in
	 * target_core_fabric_configfs.c
	 */
	.fabric_make_wwn =		&ft_add_lport,
	.fabric_drop_wwn =		&ft_del_lport,
	.fabric_make_tpg =		&ft_add_tpg,
	.fabric_drop_tpg =		&ft_del_tpg,
	.fabric_post_link =		NULL,
	.fabric_pre_unlink =		NULL,
	.fabric_make_np =		NULL,
	.fabric_drop_np =		NULL,
	.fabric_make_nodeacl =		&ft_add_acl,
	.fabric_drop_nodeacl =		&ft_del_acl,
};

int ft_register_configfs(void)
{
	struct target_fabric_configfs *fabric;
	int ret;

	/*
	 * Register the top level struct config_item_type with TCM core
	 */
	fabric = target_fabric_configfs_init(THIS_MODULE, "fc");
	if (IS_ERR(fabric)) {
		pr_err("%s: target_fabric_configfs_init() failed!\n",
		       __func__);
		return PTR_ERR(fabric);
	}
	fabric->tf_ops = ft_fabric_ops;

	/* Allowing support for task_sg_chaining */
	fabric->tf_ops.task_sg_chaining = 1;

	/*
	 * Setup default attribute lists for various fabric->tf_cit_tmpl
	 */
	TF_CIT_TMPL(fabric)->tfc_wwn_cit.ct_attrs = ft_wwn_attrs;
	TF_CIT_TMPL(fabric)->tfc_tpg_base_cit.ct_attrs = NULL;
	TF_CIT_TMPL(fabric)->tfc_tpg_attrib_cit.ct_attrs = NULL;
	TF_CIT_TMPL(fabric)->tfc_tpg_param_cit.ct_attrs = NULL;
	TF_CIT_TMPL(fabric)->tfc_tpg_np_base_cit.ct_attrs = NULL;
	TF_CIT_TMPL(fabric)->tfc_tpg_nacl_base_cit.ct_attrs =
						    ft_nacl_base_attrs;
	TF_CIT_TMPL(fabric)->tfc_tpg_nacl_attrib_cit.ct_attrs = NULL;
	TF_CIT_TMPL(fabric)->tfc_tpg_nacl_auth_cit.ct_attrs = NULL;
	TF_CIT_TMPL(fabric)->tfc_tpg_nacl_param_cit.ct_attrs = NULL;
	/*
	 * register the fabric for use within TCM
	 */
	ret = target_fabric_configfs_register(fabric);
	if (ret < 0) {
		pr_debug("target_fabric_configfs_register() for"
			    " FC Target failed!\n");
		target_fabric_configfs_free(fabric);
		return -1;
	}

	/*
	 * Setup our local pointer to *fabric.
	 */
	ft_configfs = fabric;
	return 0;
}

void ft_deregister_configfs(void)
{
	if (!ft_configfs)
		return;
	target_fabric_configfs_deregister(ft_configfs);
	ft_configfs = NULL;
}

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

static int __init ft_init(void)
{
	if (ft_register_configfs())
		return -1;
	if (fc_fc4_register_provider(FC_TYPE_FCP, &ft_prov)) {
		ft_deregister_configfs();
		return -1;
	}
	blocking_notifier_chain_register(&fc_lport_notifier_head, &ft_notifier);
	fc_lport_iterate(ft_lport_add, NULL);
	return 0;
}

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);
	ft_deregister_configfs();
	synchronize_rcu();
}

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