/*******************************************************************************
 * 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/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_fabric.h>
#include <target/target_core_fabric_configfs.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 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_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;
        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;
        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);

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

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

        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", lacl->name);
        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,
        .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,
        /*
         * 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);