// SPDX-License-Identifier: GPL-2.0-or-later
/*******************************************************************************
 * 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>
 *
 ****************************************************************************/

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <generated/utsrelease.h>
#include <linux/utsname.h>
#include <linux/hex.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 <linux/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, 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_obj(*tpg);
        if (!tpg)
                return NULL;
        tpg->index = index;
        tpg->lport_wwn = ft_wwn;
        INIT_LIST_HEAD(&tpg->lun_list);

        wq = alloc_workqueue("tcm_fc", WQ_PERCPU, 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_obj(*ft_wwn);
        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_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 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,
        .fabric_name =                  "fc",
        .node_acl_size =                sizeof(struct ft_node_acl),
        .tpg_get_wwn =                  ft_get_fabric_wwn,
        .tpg_get_tag =                  ft_get_tag,
        .tpg_get_inst_index =           ft_tpg_get_inst_index,
        .check_stop_free =              ft_check_stop_free,
        .release_cmd =                  ft_release_cmd,
        .close_session =                ft_sess_close,
        .sess_get_index =               ft_sess_get_index,
        .sess_get_initiator_sid =       NULL,
        .write_pending =                ft_write_pending,
        .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,

        .default_submit_type            = TARGET_DIRECT_SUBMIT,
        .direct_submit_supp             = 1,
};

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);